Modified polymer and manufacturing method therefor

Abstract

A modified polymer and a manufacturing method therefor. A part of the molecular chain of a polymer is opened, and changed into a resin intermediate containing a molecular fragment, of the initial polymer, having an active group or a modified resin containing a molecular fragment, of the initial polymer, having a chain extension group, or, by means of a grafting reaction, the resin intermediate is changed into a modified resin containing a molecular fragment, of the initial polymer, having a chain extension group; and the modified resin is then cured into a modified polymer, or, the modified resin and a curing agent are mixed to prepare a semi-cured material, or a filler or a fiber is added during the process of manufacturing the semi-cured material, so as to prepare a semi-cured material of a composite material, and the semi-cured material is then cured to prepare a modified polymer or a modified polymer composite material. During the process, the molecular weight and molecular structure of the initial polymer are adjusted by means of the design and control of a chemical reaction, and the modified polymer having the target performance is obtained by means of the design and control of an additive.

Description

A modified polymer and a method for producing the same

[0001] This application claims: Chinese Patent Application No. CN202311128682.X filed on September 1, 2023, Chinese Patent Application No. CN202410237427.7 filed on March 1, 2024, Chinese Patent Application No. CN202410237428.1 filed on March 1, 2024, Chinese Patent Application No. CN202410237429.6 filed on March 1, 2024, Chinese Patent Application No. CN202410236493.2 filed on March 1, 2024, Chinese Patent Application No. CN202411202588.9 filed on August 29, 2024, Chinese Patent Application No. The present invention claims priority to Chinese patent application No. CN202411202586.X, priority to Chinese patent application No. CN202411207579.9 filed on August 29, 2024, priority to Chinese patent application No. CN202411205184.5 filed on August 29, 2024, priority to Chinese patent application No. CN202411207649.0 filed on August 29, 2024, priority to Chinese patent application No. CN202411205199.1 filed on August 29, 2024, and priority to Chinese patent application No. CN202411205168.6 filed on August 29, 2024, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] This patent relates to the field of polymer material technology, and involves a modified polymer and a method for manufacturing the same. Background Art

[0003] "Progress in the Development of Raw Materials or Chemical Recycling of Waste Polymers" (Liu Chun. Nanjing Research Institute of Sinopec Yangzi Petrochemical Co., Ltd., Nanjing, 210048, Plastic Additives, Issue 4, 2020 (Total Issue 142)) introduces that the chemical recycling of polymers includes raw material recycling and chemical recycling. Raw material recycling is to turn waste plastics into petroleum raw materials for the production of petrochemicals or plastics. It usually does not cause the deterioration of the performance of chemicals or plastics, and there are no restrictions on their performance. The thermal recovery of raw materials uses high temperatures to break the chemical bonds of the polymer skeleton. This decomposition is called high-temperature degradation or thermal cracking when it is carried out in the absence of air, hydrogenation when it is carried out in a hydrogen atmosphere, and gasification when a controllable amount of oxygen is present. Depending on the change route, the quality and composition of the final product are also different. Chemical recycling is to convert polymers into monomers or monomer fragments through chemical reactions, and polymerize them again. The new polymers obtained are no different in essence from the original polymers.

[0004] Disadvantages of chemical polymer recycling include compositional fluctuations, impurities, mechanical property loss due to degradation, and a lack of standardized and variable raw material supply. Even a single polymer (such as PE) has a wide range of melt indices and thermal stability. Separating waste plastics into their individual components is essential before raw material or chemical recycling, and is an essential process step, followed by the removal of impurities.

[0005] Existing polymer recycling has problems such as high energy consumption, high cost, and by-product pollution caused by impurity removal and purification. Improvements are urgently needed to overcome the disadvantages of polymer recycling and obtain polymers that better meet production standards.

[0006] Summary of the Invention

[0007] The present invention provides a modified polymer and a preparation method thereof, which can solve the key problems of existing polymer recovery, namely, high energy consumption, high cost and by-product pollution caused by impurity removal and purification.

[0008] The present invention provides a method for producing a modified polymer. The modified polymer is obtained by treating an initial polymer, the treatment comprising the following steps:

[0009] Step A: The initial polymer reacts with a degradation agent containing an active group to break at least a portion of the molecular chain of the initial polymer to form a resin intermediate containing molecular chain fragments of the initial polymer with active groups;

[0010] Step C: reacting the resin intermediate with a grafting agent having a grafting group to prepare a modified resin containing an initial polymer molecular chain segment having a chain extending group, that is, a modified resin containing an initial polymer molecular chain segment having a chain extending group, wherein the chain extending group can be on the degradation agent molecule or on the grafting agent molecule;

[0011] Step I: The modified resin is then mixed with a curing agent, and the initial polymer molecular chain fragments in the modified resin are reconnected into new macromolecules through the reaction between the curing agent and the chain extending groups or through the curing agent initiating the reaction between the chain extending groups to prepare a modified polymer.

[0012] The present invention also provides another method for producing a modified polymer, wherein the modified polymer is obtained by treating an initial polymer, the treatment comprising the following steps:

[0013] Step C: first reacting the initial polymer with a grafting agent containing a chain extending group to break the polymer molecular chain to form a modified resin containing the initial polymer molecular chain fragments with the chain extending group, that is, a modified resin containing the initial polymer molecular chain fragments with the chain extending group;

[0014] Step I: mixing the modified resin with a curing agent, and reconnecting the initial polymer molecular chain fragments in the modified resin into new macromolecules through the reaction between the curing agent and the chain extending groups or through the curing agent initiating the reaction between the chain extending groups, thereby preparing a modified polymer.

[0015] The present invention also provides another method for producing a modified polymer, wherein the modified polymer is obtained by treating an initial polymer, the treatment comprising the following steps:

[0016] Step 5: then mixing the modified resin prepared according to the aforementioned method for preparing a modified polymer with a curing agent, and then cooling the mixed resin to prepare a semi-cured material containing the curing agent.

[0017] Step g: heating the semi-cured material to cause the curing agent to react with the chain extending groups or the curing agent to induce the chain extending groups to react with each other so that the initial polymer molecular chain fragments in the modified resin are reconnected to form new macromolecules to prepare a modified polymer.

[0018] Furthermore, the heating method includes one or more combinations of conduction, infrared, microwave, irradiation, ultraviolet, ultrasonic, heat medium, hot air or electromagnetic wave heating methods.

[0019] Optionally, in the method for manufacturing a modified polymer in the first to third aspects above, step 1 also includes the step of adding a filler or other additive to the modified resin and / or the step of impregnating the modified resin into the fiber, thereby preparing a composite semi-cured material, and then preparing a composite material with the modified polymer as the matrix; the filler includes a solid or liquid additive that does not chemically react with the initial polymer.

[0020] Optionally, the initial polymer contains fillers or fibers, and in steps a to f, at least a portion of the fillers or fibers in the initial polymer are retained to prepare a composite semi-cured material. Further, in step g, a modified polymer containing fillers and / or reinforcing materials that meets the target application requirements is prepared, that is, a composite material with the modified polymer as a matrix.

[0021] Part 1 Aspect 2

[0022] The second aspect of the first part of the present invention further provides a modified polyurethane resin, a prepreg, a composite material, and a preparation method thereof. These can address key challenges in existing polyurethane solid waste recycling, namely, the high energy consumption, high costs, and byproduct pollution caused by impurity removal and purification.

[0023] The present invention provides a method for preparing a modified polyurethane resin. The modified polyurethane is obtained by treating an initial polyurethane, and the treatment comprises the following steps:

[0024] Step A: subjecting the initial polyurethane to a degradation reaction with a degradation agent having an active group to break at least a portion of the molecular chain of the initial polyurethane to produce a resin intermediate containing molecular fragments of the initial polyurethane and the active group; wherein the initial polyurethane includes a thermoplastic polyurethane having a linear or branched molecular structure and a thermosetting polyurethane having a cross-linked network molecular structure, and the molecular weight of the initial polyurethane is not less than 10,000 g / mol;

[0025] Step C: reacting the resin intermediate with a grafting agent having a grafting group to prepare a modified polyurethane resin containing an initial polymer molecular chain segment having a chain extending group, that is, preparing a modified polyurethane resin containing an initial polymer molecular chain segment having a chain extending group.

[0026] Furthermore, the initial polyurethane includes pure polyurethane and / or polyurethane composite; the polyurethane composite contains fillers and / or fibers, and the fillers include solid or liquid additives that do not chemically react with the initial polyurethane.

[0027] Furthermore, the initial polyurethane includes at least one polyurethane waste that has lost its use function, or the resin intermediate is prepared by compounding multiple resin intermediates made from the initial polyurethane.

[0028] Furthermore, in the step A, the initial polyurethane comprises a thermoplastic polyurethane having a linear or branched molecular structure and / or a thermosetting polyurethane having a cross-linked network molecular structure.

[0029] Furthermore, the degradation reaction includes one or more combinations of thermal decomposition, hydrolysis, alcoholysis, esterification, transesterification, aminolysis, acidolysis, alkaline hydrolysis, alcohol-alkali reaction, hydrogenolysis or acylation reaction.

[0030] Furthermore, in step A, the degradation agent carries a chain-extending group having a chain growth or cross-linking function, and the chain-extending group can react with other groups or itself to achieve molecular chain growth or cross-linking; the grafting group includes a combination of one or more of an amide group, an amine group, a urea group, a hydroxyl group, a carboxyl group, an anhydride group or an epoxy group, and the chain-extending group includes a combination of one or more of an amide group, an urea group, an amine group, a hydroxyl group, a carboxyl group, a carboxylate, an unsaturated double bond, an ester group, an epoxy group or an aldehyde group.

[0031] Furthermore, the degradation agent contains at least one active group, which includes a combination of one or more of a hydroxyl group, an amide group, an acyl salt group, a urea group, an amine group, a carboxyl group, an anhydride group, a carboxylate group, an unsaturated double bond or triple bond, an ester group, a cyano group, a nitro group, a carbonyl group or an epoxy group.

[0032] Furthermore, the degradation agent is an alcoholysis agent, the degradation agent includes a polyol, the polyol includes a diol and / or a high-functionality polyol; the alcoholysis reaction temperature is 110-150°C, 150-170°C, 170-180°C, 180-200°C, 200-220°C or 220-250°C; the alcoholysis reaction time is 0.5-2h, 2-3h, 3-6h, 6-12h, 12-24h, 24-48h or 48-64h; the alcoholysis reaction yield is 50-60%, 60-70%, 70-80%, 80-95%, 95-100%; the resin intermediate adopts RID and VWD (2 The number average molecular weight measured by two detectors (54 nm) is 150-200; 200-350; 350-700; 700-1000, 700-1000, 1000-1800, 1800-3000, 3000-5000, 5000-10000, 10000-30000 or 30000-60000 g / mol; the viscosity at room temperature (25°C) is 50-200 mPa·s, 200-500 mPa·s, 500-1000 mPa·s, 1000-2000 mPa·s, 2000-10000 mPa·s, 10000-20000 mPa·s, 20000~60000mPa·s, 60000~200000mPa·s, 200000~600000mPa·s or 600000~1800000mPa·s.

[0033] Furthermore, in the step A, the initial polyurethane molecular chain carries a chain-breaking group, and in the step A, the molecular chain of the initial polyurethane is broken at the chain-breaking group.

[0034] Furthermore, in step A, the chain-scissoring group includes one or more combinations of -N(H)n-, -NH-(CO)-O-, -C=C-, -C≡C-, -O-, -HN-(CO)-NH-, -(CO)-NH-, -NH-(CS)-O-, -C=C-, -S-, -HN-(CS)-NH-, -(CS)-NH-, heterocycle, paracycle, aromatic ring, hexylcycle, macrocycle, polyhedron, isomer or polypeptide.

[0035] Furthermore, after step A is completed, there is a step of removing at least a portion of the degradation products, wherein the removal step comprises a combination of one or more of reduced pressure distillation, separation, filtration, extraction, and fractionation; and the degradation products include at least a portion of the degradation agent and / or solvent that did not participate in the reaction.

[0036] Furthermore, the method further comprises the following steps: Step B: removing and recovering the excess degradation agent in the resin intermediate prepared in Step A.

[0037] Furthermore, in the step B, the removal method includes the reduced pressure distillation.

[0038] Furthermore, in the step C, it further includes: reacting the resin intermediate with a grafting agent having a grafting group, and performing the reduced pressure distillation on the reaction product to prepare a modified polyurethane resin containing an initial polymer molecular chain fragment with a chain extending group, that is, preparing a modified polyurethane resin containing an initial polymer molecular chain fragment with a chain extending group.

[0039] Furthermore, the temperature of the reduced pressure distillation is 65-95°C, 95-120°C, 120-150°C or 150-200°C; the pressure of the reduced pressure distillation is 0.01-2 mmHg, 2-5 mmHg, 5-20 mmHg, 20-100 mmHg or 100-400 mmHg.

[0040] Furthermore, in the step C, the grafting reaction includes a chemical bonding reaction with a substance containing an active double bond.

[0041] Furthermore, the grafting reaction is an esterification reaction.

[0042] Further, the grafting agent includes one or more selected from acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, mono-2-(acryloyloxy)ethyl phthalate, mono-2-(methacryloyloxy)ethyl phthalate, N-(carboxyphenyl)maleimide, N-(carboxyphenyl)methacrylamide, N-(carboxyphenyl)acrylamide or methacryloyl chloride;

[0043] Furthermore, the grafting reaction is an esterification reaction with acrylic acid and / or methacrylic acid.

[0044] The present invention claims protection for the modified polyurethane resin prepared by any one of the above preparation methods.

[0045] The present invention also claims protection for a composite material using any one of the above-mentioned modified polyurethane resins as a matrix.

[0046] Furthermore, the composite material includes a modified polyurethane resin and a reinforcing material, wherein the reinforcing material includes fibers;

[0047] The fibers include one or a combination of fiber fabrics, continuous fiber yarns, short-cut fibers, pelletized fibers, powdered fibers, or fillers.

[0048] The present invention further provides a method for preparing the composite material, comprising the following steps: Step e, impregnating fibers with a modified polyurethane resin at 0-150° C. to produce the composite material.

[0049] Furthermore, the method further includes the following steps:

[0050] Step H-1: adding a curing agent to the composite material to carry out a curing reaction to obtain a cured resin;

[0051] The curing agent contains a compound capable of reacting with a chain extending group, or a compound capable of initiating a mutual reaction between chain extending groups. Furthermore, the reactive functional group of the compound that reacts includes one or a combination of free radical initiators, isocyanate groups, acid anhydrides, carboxyl groups, epoxy groups, amine groups, amide groups or aldehydes; the free radical initiator includes a thermosensitive free radical initiator; the thermosensitive free radical initiator includes peroxides, persulfides, peroxycarbonates, peroxyboric acid, azo compounds or other suitable free radical initiators that can initiate the curing of double bond-containing compounds.

[0052] The present invention further provides a method for preparing the modified polyurethane resin as a semi-cured material for curing the modified polyurethane resin, comprising the following steps:

[0053] Step 2: Add a curing agent to the modified polyurethane resin and mix them to prepare a semi-cured material.

[0054] Furthermore, the curing agent contains a compound capable of reacting with a chain extending group, or a compound capable of initiating a mutual reaction between chain extending groups. Furthermore, the reactive functional group of the compound that reacts includes one or a combination of free radical initiators, isocyanate groups, acid anhydrides, carboxyl groups, epoxy groups, amine groups, amide groups or aldehydes; free radical initiators include thermosensitive free radical initiators; thermosensitive free radical initiators include peroxides, persulfides, peroxycarbonates, peroxyboric acid, azo compounds or other suitable free radical initiators that can initiate the curing of double bond-containing compounds.

[0055] Furthermore, the semi-cured material is obtained by a free radical polymerization reaction of the modified polyurethane in the presence of the free radical initiator; the free radical initiator includes tert-butyl peroxyisopropyl carbonate, methyl ethyl ketone peroxide, potassium persulfate, cumene hydroperoxide, dibenzoyl peroxide, tert-butyl peroxybenzoate or 2,4-di-tert-butyl peroxide isopropylbenzene; the curing agent also includes an accelerator compatible with the free radical initiator; the accelerator includes a metal salt, an organic amine, including a cobalt salt, a copper salt, a zinc salt or an aniline accelerator.

[0056] Furthermore, in step 2, the modified polymer is heated to 50° C. to 180° C.

[0057] The present invention claims protection for a semi-cured material prepared by any one of the above preparation methods.

[0058] The present invention further provides a composite material based on the above-mentioned semi-cured material, namely, a composite material semi-cured material.

[0059] Furthermore, the composite material, i.e., the composite semi-cured material includes a semi-cured material and a reinforcing material, wherein the reinforcing material includes fibers and / or fillers; the fiber morphology includes one or a combination of fiber fabric, continuous fiber yarn, chopped fiber, lumped fiber, and powdered fiber; the composite material is prepared under reaction conditions where free radical polymerization occurs, and together with the reinforcing material, forms a composite material based on the semi-cured material, i.e., a composite semi-cured material.

[0060] The present invention also provides an application of the composite material, namely, a composite semi-cured material, in a composite prepreg, a sheet molding compound (SMC), or a bulk molding compound (BMC).

[0061] The present invention claims a method for preparing the composite material according to the above, comprising the following steps:

[0062] Step g: heating the semi-cured material to 50-160° C. and impregnating the fibers and / or fillers to produce the composite material, namely the composite semi-cured material.

[0063] Furthermore, the composite material, that is, the composite material semi-cured material includes a semi-cured material and a reinforcing material, and the reinforcing material includes fibers; the form of the fibers includes one or a combination of fiber fabrics, continuous fiber yarns, chopped fibers, lumped fibers, powdered fibers, and fillers; the composite material is prepared under reaction conditions where free radical polymerization occurs, and together with the reinforcing material, forms a composite material based on the semi-cured material; the process of impregnating fibers and / or fillers includes: one or more combinations of methods such as high-speed stirring, centrifugal stirring, screw mixing, rubber roller kneading, stirring and kneading, making a rubber film composite roller pressing, diluting and then impregnating, and composite and then rolling.

[0064] The composite material, i.e., the composite semi-cured material, is prepared by one or more combinations of pultrusion, prepreg, SMC / BMC, winding, resin transfer, vacuum infusion, hand lay-up, compression molding, and injection molding, i.e., a composite product.

[0065] The present invention provides a method for producing modified polyurethane, wherein the modified polyurethane is obtained by treating initial polyurethane (the initial polyurethane is a solidified polyurethane that needs to be recycled for reuse), and the treatment comprises the following steps:

[0066] Step A: The initial polyurethane reacts with a degradation agent containing an active group to break at least a portion of the molecular chain of the initial polyurethane to form a resin intermediate containing initial polyurethane molecular chain fragments with active groups;

[0067] Step C: reacting the resin intermediate with a grafting agent having a grafting group to prepare a modified polyurethane resin containing an initial polyurethane molecular chain segment with a chain extending group, that is, preparing a modified polyurethane resin containing an initial polymer molecular chain segment with a chain extending group. The chain extending group can be on the degradation agent molecule or on the grafting agent molecule.

[0068] Step 1: The modified polyurethane is then cured, and the initial polyurethane molecular chain fragments in the resin intermediate are reconnected into new macromolecules through the reaction of the curing agent with the chain extending group or through the curing agent initiating the reaction of the chain extending groups to each other, thereby preparing a cured modified polyurethane resin material.

[0069] The present invention also provides another method for manufacturing a composite material based on a modified polyurethane resin material. The modified polyurethane resin material is obtained by grafting a resin intermediate obtained by treating an initial polyurethane, and the resin intermediate is obtained by reacting a polyurethane solid with a degradation agent containing active groups. The specific reaction process is to interrupt at least a portion of the initial polyurethane molecular chain, thereby forming a resin intermediate containing initial polyurethane molecular chain fragments with active groups. The polyurethane solid is mainly sourced from polyurethane solid waste:

[0070] According to the aforementioned method for producing modified polyurethane and composite materials, the resin intermediate for preparing the modified polyurethane resin material is preferably obtained by alcoholysis reaction of the initial polyurethane solid.

[0071] According to the aforementioned method for producing modified polyurethane and composite materials, the modified polyurethane resin material is obtained by grafting acrylic acid and / or methacrylic acid ester groups onto a resin intermediate through an esterification reaction.

[0072] According to the aforementioned method for manufacturing modified polyurethane and composite materials, the cured modified polyurethane resin material is obtained by adding a free radical initiator to cause free radical polymerization of the modified polyurethane resin.

[0073] According to the aforementioned method for manufacturing modified polyurethane and composite materials, optionally, a composite material can be prepared by adding fillers or other additives to the modified polyurethane resin and / or impregnating the modified polyurethane resin into fibers, thereby preparing a composite material and further preparing a composite material with the modified polyurethane as the matrix; the filler includes a solid or liquid additive that does not chemically react with the initial polyurethane.

[0074] The thermosetting polyurethane resin composite material can be prepared by various composite material preparation processes, including but not limited to pultrusion process, prepreg process, SMC / BMC process, winding process, resin transfer process, vacuum infusion process, hand lay-up process, compression molding process, injection molding process, etc. or a combination thereof.

[0075] Optionally, the initial polyurethane contains fillers or fibers, and in steps A to F, at least a portion of the fillers or fibers in the initial polyurethane is retained to prepare a composite semi-cured material. Further, through the curing step in step F, a modified polyurethane containing fillers and / or reinforcing materials that meets the target application requirements is prepared, that is, a composite material with the modified polyurethane as a matrix.

[0076] This method can not only avoid the purification step of the initial polymer, reduce costs, and avoid contamination by purification by-products, but also fully retain and utilize the structure and performance of the original filler and / or reinforcement material, to produce a modified polymer containing fillers and / or reinforcement materials that meets the target application requirements, that is, a composite material with the modified polymer as the matrix.

[0077] In the industrial-scale implementation of this method, a standard initial degradation agent and / or grafting agent is first used to perform initial modification on an initial polymer mixed waste of unknown composition to obtain an initial modified resin, and then the initial modified resin is solidified to form an initial modified polymer. The initial modified polymer is then compared with the performance of the target polymer, and the initial modified resin is molecularly characterized and compared with the native precursor resin of the target polymer. Then, adjustments are made through different degradation agents, grafting agents, curing agents, reactive diluents, other types of resins, and other additives in steps A to F, including but not limited to adjusting one or more of the types, proportions, and contents of the aforementioned factors, so that the performance of the modified polymer resin is ultimately not lower than that of the target polymer resin, thereby achieving the performance requirements of the target application for the modified polymer.

[0078] Preferably, in step A or C, the molecular structure of the modified resin can be adjusted by combining different types of initial polymers, thereby adjusting the properties of the modified polymer.

[0079] More preferably, a compounding step can be added between step A and step C. By compounding different resin intermediates prepared using different types of initial polymers to obtain a mixed modified resin intermediate, the molecular structure of the modified resin can be adjusted, thereby adjusting the properties of the modified polymer.

[0080] Another preferred method is to add a compounding step between step C and step F, and to obtain a mixed modified resin by compounding different modified resins made from different types of initial polymers, thereby adjusting the molecular structure of the modified resin and further adjusting the properties of the modified polymer.

[0081] All three priority methods can utilize different types of polymer waste as initial polymers and change their proportions to adjust the molecular structure of the modified resin, thereby improving the performance of the modified polymer. Compared with adjusting the molecular structure of the modified resin by adding other fresh chemical raw materials, this method reduces costs and increases the consumption of polymer waste.

[0082] Another preferred method is to further add a mixture after step C to produce a modified resin mixture. By adjusting the type and content of the mixture, the molecular structure and composition of the modified resin, and thus the properties of the modified polymer, can be adjusted. Preferably, the mixture includes a combination of one or more of a diluent, another type of resin, a filler, and fiber.

[0083] Furthermore, the initial polymer may be an unfilled polymer or a polymer containing fillers, additives or reinforcing materials, and may be a thermoplastic polymer or a thermosetting polymer. Thermoplastic polymers include but are not limited to polyethylene, polypropylene, polyolefin, polyvinyl chloride, polyester, polyamide or thermoplastic polyurethane; thermosetting polymers include but are not limited to rubber, polyurethane, unsaturated polyester resin, epoxy resin, vinyl resin, acrylic resin or silicone resin.

[0084] Furthermore, the initial polymer includes a thermoplastic polymer with a linear or branched molecular structure, a thermosetting polymer with a cross-linked network molecular structure, a pure polymer or a polymer composite containing fillers and / or fibers, and the molecular weight of the initial polymer is not less than 10,000 g / mol.

[0085] In another aspect, the present invention claims a modified polymer prepared by any one of the above methods.

[0086] The principles of resin modification methods based on other polymers and their products and applications are the same and also fall within the scope of protection of the present invention.

[0087] The present invention also claims a method for producing a modified polymer as a resin intermediate, wherein the modified polymer is obtained by treating an initial polymer, the treatment comprising the following steps:

[0088] A: The initial polymer is subjected to a degradation reaction with a degradation agent having an active group, thereby breaking at least a portion of the molecular chain of the initial polymer and preparing a resin intermediate containing molecular chain fragments of the initial polymer having an active group.

[0089] The initial polymer includes a thermoplastic polymer with a linear or branched molecular structure and a thermosetting polymer with a cross-linked network molecular structure, and the molecular weight of the initial polymer is not less than 10,000 g / mol.

[0090] Furthermore, the thermoplastic polymer includes polyethylene, polypropylene, polyolefin, polyvinyl chloride, polyester, polyamide or thermoplastic polyurethane, and the thermosetting polymer includes rubber, polyurethane, unsaturated polyester resin, epoxy resin, vinyl resin, acrylic resin or silicone resin. Preferably, the initial polymer molecular chain carries a chain-breaking group, and in step A, the molecular backbone of the initial polymer is disconnected from the chain-breaking group, and the chain-breaking group includes one or more combinations of -N(H)n-, -NH-(CO)-O-, -C=C-, -C≡C-, -C≡CN-, -(CO)-, -(CO)-O-, -O-, -HN-(CO)-NH-, -(CO)-NH-, -NH-(CS)-O-, -C=C-, -S-, -HN-CS-NH-, -CS-NH-, heterocycle, cyclic ring, aromatic ring, hexyl ring, macrocycle, polyhedron, isomer or polypeptide. Preferably, the initial polymer molecular chain has pendant groups that do not include hydrogen atoms. The pendant groups react synergistically with the degradation agent to help break the initial polymer molecules. The degradation reaction in step (a) above includes one or more combinations of thermal decomposition, hydrolysis, alcoholysis, aminolysis, acidolysis, alkaline hydrolysis, alcohol-alkali reaction, hydrogenolysis, or acidolysis.

[0091] Preferably, the degradation reaction comprises the following reaction: R1-A-(R2S)+R3-B-→R1-(A1)-R3-B1-+(R2S)-B2-

[0092] Among them, -R1-A-(R2S)- is the initial polymer, A is the chain-breaking group, S is the side group, R3-B- is the degradant, and -B- is the active group of the degradant; R1-(A1)-R3-B1- and (R2S)-B2- are initial polymer molecular fragments formed after the initial polymer chain breaks, -A1- is the group formed after the degradation reaction of the chain-breaking group A, -B1- and -B2- are respectively active groups formed by the active end group B of the degradant at the two ends of the broken molecular chain, and the active groups A1 or B1 or B2 participate in subsequent reactions.

[0093] Preferably, the weight ratio of the initial polymer to the degradation agent is 1:0.1-0.4, 1:0.4-2, 1:2-5 or 1:5-15.

[0094] Polyurethane (PU), a typical application of the present invention, is a prime example of a starting polymer. It ranks fifth in total polymer production volume based on production scale and has a large market. Therefore, the present invention utilizes polyurethane as the starting polymer for recycling and modification. The present invention provides a method for modifying polyurethane, utilizing solidified starting polymers, particularly polyurethane waste, to produce the modified polymer. This method reduces the use of isocyanates in the polyurethane resin manufacturing process, reduces moisture sensitivity, and extends process life. Furthermore, the polyurethane molecular structure is optimized, significantly improving the overall performance of the modified polymer.

[0095] Existing polyurethanes are materials produced by reacting isocyanate groups with isocyanate reactants containing active hydrogen atoms that react with the isocyanate groups. Commonly used isocyanate reactants include hydroxyl-containing polyols, amine-containing polyamines, thiol compounds containing mercapto groups, and combinations thereof. Based on performance characteristics, polyurethanes are primarily categorized into three main categories: rigid polyurethanes, flexible polyurethanes, and polyurethane elastomers. By product and application, polyurethane rigid foam insulation materials, polyurethane soft foam cushioning materials, and polyurethane elastomer wear-resistant materials account for the majority. Polyurethanes are also widely used in coatings, adhesives, fibers, thermoplastics, and other specialty polymers. Polyurethane resins are typically prepared and used as two-component resin systems. The component containing isocyanate groups is often referred to as the isocyanate component, also known as the black component; the component containing isocyanate-reactive functional groups is often referred to as the polyol component, also known as the white component. Existing polyurethane production methods involve directly formulating a two-component resin made from a polyol component and an isocyanate component for use in the production of polyurethane. However, because the isocyanate group readily reacts with water to form carbon dioxide and urea, the resulting polymer produces bubbles, resulting in reduced performance. Furthermore, the gel time is too fast, requiring rapid production operations. This limits process time, and the process is often carried out in a sealed, high-temperature, and high-pressure environment, placing high demands on production equipment. This is particularly true in the composite materials industry, such as in traditional pultrusion, winding, hand lay-up, spraying, and vacuum infusion processes, where the resin must be moisture-insensitive, have a process time of more than four hours, and cure at room temperature or below 80°C. These properties are unattainable with existing polyurethane resins, requiring specialized processes that utilize complex equipment and molds to shorten operation times and isolate moisture in order to produce polyurethane composites. This severely limits the scope of polyurethane applications.

[0096] Based on the problems existing in the existing polyurethane manufacturing methods, the solution of the present invention is that in step A, the initial polymer adopts a thermoplastic polyurethane TPU with a linear or branched molecular structure and / or a thermosetting polyurethane with a cross-linked network molecular structure; wherein, the initial polymer molecular chain has a chain-breaking group, and in step A, the initial polymer is reacted with a degradation agent to break the molecular weight of the initial polymer from the chain-breaking group.

[0097] Furthermore, in step A, the initial polyurethane is mixed with a degradation agent to undergo a degradation reaction, thereby producing a resin intermediate containing molecular fragments and active groups of the initial polyurethane. Preferably, the initial polyurethane is subjected to a pulverization process, which includes but is not limited to one or more combinations of crushing, shearing, grinding, ball milling, grinding, air flow milling, and ultrasonic milling; the mixing method of the initial polyurethane and the degradation agent includes but is not limited to one or more combinations of high-speed stirring, centrifugal stirring, kneading, mixing, screw extrusion, grinding, and ball milling;

[0098] Furthermore, the chain-breaking groups include -N(H)n-, -NH-(CO)-O-, -HN-(CO)-NH-, The degradation reaction includes one or more of alcoholysis, alkaline hydrolysis, hydrolysis, aminolysis, thermal decomposition, alcohol-glaze reaction, hydrogenolysis or acidolysis; the degradation reaction may include the following reactions:

[0099] Alcoholysis: PU+HO-R-OH to obtain a polyol mixture

[0100] Hydrolysis method: PU + water to obtain polyol + polyamine

[0101] Alkaline hydrolysis: PU + NaOH to obtain amine + alcohol + Na2CO3

[0102] Ammonolysis: PU + NH3 to obtain polyol + amine + urea

[0103] Pyrolysis: PU + high temperature to obtain a mixture of gaseous and liquid fractions

[0104] Hydrocracking method: PU+H2 high temperature and high pressure to obtain a mixture of oil and gas

[0105] Furthermore, in step A, the initial polyurethane as the initial polymer is a polymer compound containing a chain-breaking group (AB), a main chain X, and a Y, and is prepared by the initial isocyanate XA a and initial polyol YB b The reaction generates; the degradation agent is MC cThe active group C of the degradation agent reacts with the chain-scission group (AB) to break the initial polyurethane molecules, forming a resin intermediate containing initial polymer molecular fragments with new active groups B and C. The degradation reaction is as follows (schematic diagram):

[0106] Where A is the isocyanate group in the initial polyurethane, B is the hydroxyl group in the initial polyurethane, (AB) is the carbamate group in the initial polyurethane; X is the initial isocyanate backbone; Y is the initial polyol backbone; M is the degradation agent backbone; C is the active group of the degradation agent, including hydroxyl, active hydrogen, amine, or alkali metal groups; a, b, and c are functional groups. The above is a typical degradation reaction mechanism, where a=2, b=3, and c=1 or 2. Other combinations of a, b, and c functional groups have similar degradation reactions and fall within the scope of protection of this invention.

[0107] Furthermore, in step A, the degradation agent contains at least one active end group, and the active end group includes one or more of a hydroxyl group, an amide group, an acyl salt group, a urea group, an amine group, a carboxyl group, an anhydride group, a carboxylate group, an unsaturated double bond or triple bond, an ester group, a cyano group, a nitro group, a carbonyl group, or an epoxy group.

[0108] Preferably, the initial polyurethane includes carbamate groups, and the degradation agent includes hydroxyl groups. In the degradation reaction, the hydroxyl groups react with the carbamate groups and open at least a portion of the carbamate bonds to generate a resin intermediate containing initial polyurethane molecular fragments with active amino and hydroxyl groups.

[0109] As a typical example of the present invention, the initial polymer is a polyurethane whose molecular backbone contains urethane groups. The degradation reaction includes an alcoholysis reaction. The active end group contained in the degradation agent is a hydroxyl group. During the degradation reaction, the hydroxyl group reacts with the chain-scission group and breaks at least a portion of the urethane bonds on the initial polymer molecular chain, generating a resin intermediate having a linear or branched molecular structure containing the initial polyurethane molecular fragment and the active hydroxyl group. The degradation reaction includes the following reaction: -R1NHCOOR2-+R3(OH)n→-R1NHCOOR3(OH) (n-1) -+-R2OH

[0110] Among them, -NHCOO- is a carbamate group; R3(OH)n is a degradant, and n is greater than 1; -R1NHCOOR3(OH)(n-1)- is a molecular chain fragment containing R1 and a carbamate group and an active group hydroxyl group in the initial polyurethane molecular chain, and -R2OH is a molecular chain fragment containing R2 and at least one active group hydroxyl group in the initial polyurethane molecular chain.

[0111] Furthermore, since the chemical structure of polyurethane contains urea chains -NHCONHR- in addition to the carbamate chain -NHCOOR-, the following side reactions also occur during the degradation reaction:

[0112] Side reaction of urea group: -R1-NH-CO-NH-R1-+HO-R3-OH→-R1NHCOOR3OH+-R1NH2

[0113] There are also side reactions such as thermal degradation of carbamate and urea groups: -R1-NH-CO-OR2-→-RNCO+HOR2 -R1NH-CO-O-(CH2)2-R2-→-R1NH2+CO2+CH2=CHR2 -R1-NH-CO-OO-R2-→-R1NHR2-+CO2 -R1-NH-CO-NH-R4-→-R1-NCO+R4NH2

[0114] The above side reactions will eventually generate compounds with hydroxyl or amine groups.

[0115] The above-mentioned side reactions will eventually generate compounds with hydroxyl or amine groups, which can allow the grafting agent to react with the amine-containing compound, so that there is no need to take the steps of separating and purifying the amino compound and the polyol for the resin intermediate.

[0116] Furthermore, the amines in the resin intermediates are further functionalized through a Michael addition reaction, which allows a 1,4-conjugate addition reaction to occur between the amino groups of the amines and reactive double bonds. These reactive double bonds originate from substances such as α,β-unsaturated aldehydes, ketones, esters, nitriles, and nitro compounds. The amino groups undergo a Michael addition reaction between their reactive hydrogens and reactive double bonds, as follows:

[0117] Y=CHO,C=O,COOR,NO2,CN

[0118] X=H, alkyl, aryl

[0119] R 1 =alkyl, aryl

[0120] R 2 、R 3 , R4=H, alkyl, aryl

[0121] Preferably, the molar ratio of the active double bond to the active hydrogen of the amino group is 0-100, preferably 0.01-50, preferably 0.05-20, preferably 0.1-5, preferably 0.2-3, preferably 0.3-2, preferably 0.4-1.5, preferably 0.5-1.1, preferably 0.7-1.

[0122] Furthermore, among the grafting agents, representative compounds based on such α,β-unsaturated aldehydes, ketones, esters, nitriles, and nitro compounds include, but are not limited to, hydroxypropyl methacrylate, acrylonitrile, ethyl acrylate, nitroethylene, acrolein, or propylene ethyl ketone.

[0123] Furthermore, the degradation agent includes a polyol, which includes a diol and / or a high-functionality polyol. The diol includes a low molecular weight C2-C6 diol, preferably ethylene glycol, propylene glycol, 1,4-butanediol monoethylene glycol, propylene glycol monoether, or neopentyl glycol. The high-functionality polyol includes glycerol, trimethylolethane, pentaerythritol, sucrose polyol, or sorbitol, and also includes various polyether polyols based on small molecule initiators, such as NJ-301, NJ-303, NJ-3063, NJ-430H, NJ-6305C, NJ-403, NJ-4110, NJ-330N, NJ-204, etc.

[0124] Furthermore, the polyol is used as an alcoholysis agent in combination with an alcoholysis co-agent, and the alcoholysis co-agent is a tertiary amine.

[0125] Furthermore, the alcoholysis agent is used in combination with a metal organic compound as a catalyst to effectively promote the alcoholysis reaction and reduce the content of polyamines in the product; preferably, the metal organic compound as a catalyst includes Ti[O(CH2)3CH3]4 or CH3COOK, and most preferably, Ti[O(CH2)3CH3]4 is selected, and the hydroxyl value and viscosity of the obtained product are more moderate.

[0126] Furthermore, a catalyst is added to the alcoholysis agent to accelerate the degradation reaction, and the catalyst is selected from one or more of guanidines, amidines, tins or amines, and the catalyst includes one or more of triethylamine, 1,5,7-triazidobicyclo(4.4.0)dec-5-ene, 1,8-diazabicycloundec-7-ene, benzenesulfonic acid, (4-methylphenyl)diphenylsulfoniumtrifluoromethanesulfonic acid, tin salts, zinc salts, calcium salts, magnesium salts or cobalt salts; preferably, the amount of the catalyst added is 0.01wt%-10wt% of the initial polyurethane.

[0127] Preferably, the alcoholysis agent comprises one or a combination of a diol and a high-functionality polyol, and the weight ratio of the diol to the high-functionality polyester polyol is 1:0-0.3, 1:0.3-0.6, 1:0.6-1, 1:1-2 or 1:2-4. If the ratio of the diol is too high, more diol will remain in the product, making the post-processing of the product difficult. At the same time, the alcoholysis product containing free diol is difficult to completely remove, resulting in problems such as excessively high hydroxyl value or difficulty in adjustment.

[0128] Preferably, the initial polymer is polyurethane waste, including rigid foam for refrigerator insulation, cold storage insulation, refrigerated truck and refrigerated container insulation, building insulation, and other rigid foams, sofas, seats, mattress soft foam, packaging cushioning sponge, shoe soles, roller coverings, screens, conveyor belts, other elastomers, spandex, or TPU products. The method for producing modified polyurethane using a resin intermediate obtained through a degradation reaction can be used to manufacture polyurethane products, coatings, adhesives, and other chemicals, including rigid and flexible PU foams, elastomers, composite materials, epoxy resin crosslinkers, unsaturated resins, vinyl resin modifiers, and crosslinkers for polyurethane rubber.

[0129] Preferably, the weight ratio of polyurethane waste PU as the initial polymer to the degradation agent is 1:0.1-0.3, 1:0.3-0.5, 1:0.5-1, 1:1-2, 1:2-4, 1:4-8 or 1:8-15. If the proportion of PU is too large, only a partial reaction will occur, and the density and viscosity of the product will also increase accordingly. If it is too small, the cost of removing the unreacted degradation agent will be too high.

[0130] Preferably, the alcoholysis reaction temperature is 110-150°C, 150-170°C, 170-180°C, 180-200°C, 200-220°C or 220-250°C. A too low reaction temperature prolongs the reaction time. Although an increase in the reaction temperature is beneficial to increasing the alcoholysis reaction speed and shortening the reaction time, it increases the content of free amines in the final product and makes the amine value or hydroxyl value of the final product too high.

[0131] The alcoholysis reaction time is 0.5 h to 64 h, preferably, 0.5 to 2 h, 2 to 3 h, 3 to 6 h, 6 to 12 h, 12 to 24 h, 24 to 48 h or 48 to 64 h.

[0132] Preferably, the yield of the alcoholysis reaction is 50-60%, 60-70%, 70-80%, 80-95% or 95-100%.

[0133] Furthermore, in step A, the degradation reaction includes an alcohol reaction or an alkaline hydrolysis reaction. It includes the following reactions:

[0134] Preferably, the base in the alkaline hydrolysis reaction can be an alkali metal hydroxide and an alkaline earth metal hydroxide, and in addition to NaO, it can also be a mixture of one or more of LiOH, KOH, and Ca(OH)2.

[0135] Furthermore, in step A, the degradation reaction includes a hydrolysis reaction or a steam cracking method, and the degradation reaction includes the following reaction under high pressure steam and high temperature conditions: R1-NH-CO-O-R2+H2O→-R1NH2+R2OH+CO2

[0136] The steam cracking temperature during the degradation reaction is 200-410°C, preferably 220-380°C.

[0137] Furthermore, the hydroxyl value of the resin intermediate obtained in step A is 10-50 mg KOH / g, 50-100 mg KOH / g, 100-180 mg KOH / g, 180-300 mg KOH / g, 300-500 mg KOH / g, 500-700 mg KOH / g or 700-1000 mg KOH / g.

[0138] Furthermore, the viscosity (25°C) of the resin intermediate obtained in step A is 50-200mPa·s, 200-500mPa·s, 500-1000mPa·s, 1000-2000mPa·s, 2000-10000mPa·s, 10000-20000mPa·s, 20000-60000mPa·s, 60000-200000mPa·s, 200000-600000mPa·s or 600000-1800000mPa·s.

[0139] Furthermore, the total amine value (KOH dosage) of the resin intermediate prepared in step A is 0-40 mg / g, 40-80 mg / g, 80-120 mg / g, 120-200 mg / g or 200-1000 mg / g.

[0140] Furthermore, in step A, the degradation reaction includes a pyrolysis reaction of the polyurethane waste, and the pyrolysis reaction includes cracking the initial polymer polyurethane waste at 180-400° C., and the products are isocyanate and recovered polyol, and the isocyanate and recovered polyol are fractionated and collected.

[0141] Furthermore, step A further comprises removing at least a portion of the degradation products, which removal step comprises a combination of one or more of vacuum distillation, separation, filtration, extraction, and fractionation. Preferably, a vacuum distillation step is included to remove at least a portion of the unreacted degradation agent, which can be collected, recovered, and reused. More preferably, the vacuum distillation temperature is 65-95°C, 95-120°C, 120-150°C, or 150-200°C; and the vacuum distillation pressure is 0.01-2 mmHg, 2-5 mmHg, 5-20 mmHg, 20-100 mmHg, or 100-400 mmHg. Preferably, in step A, a diol is used as a degradation agent, and other high-functionality polyols are added to the degradation product to reduce the viscosity of the reaction product. All or part of the diol is then removed by vacuum distillation for recovery. The weight ratio of diol to high-functionality polyol is 1:0-0.3, 1:0.3-0.6, 1:0.6-1, 1:1-2, 1:2-4, or 1:4-9. If the ratio of diol is too high, more diol will remain in the product, making post-processing of the product difficult. Furthermore, alcoholysis products containing free diols are difficult to completely remove, resulting in problems such as excessively high hydroxyl values ​​or difficulty adjusting them. Preferably, the diol is ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, diethylene glycol, or dipropylene glycol. The resulting resin intermediate has good performance and low viscosity.

[0142] On the other hand, the present invention claims a modified polymer prepared by any one of the above methods as a resin intermediate.

[0143] The present invention also provides a method for obtaining a modified polymer by subjecting a resin intermediate prepared by any of the above methods or a resin intermediate prepared by other methods to a grafting reaction. The modified polymer is obtained by treating an initial polymer, and the treatment comprises the following steps:

[0144] C: In step A, the degradation agent carries both an active group and a chain-extending group, so that a grafting reaction is carried out simultaneously with the degradation reaction to prepare a modified polymer containing molecular fragments of the initial polymer and chain-extending groups as a modified resin.

[0145] Furthermore, the chain extension group is a functional group that can react with other groups or react with each other. Furthermore, step C includes the following reaction: R1-A-(R2S)+(R3C)-B-→R1-(A1C)-R3-B1-+(CR2S)-B2-

[0146] Wherein, -R1-A-(R2S)- is an initial polymer, A is a chain-breaking group, S is a side group, (R3C)-B- is a degradation agent having both an active group and a chain-extending group, -C- is a chain-extending group; -B- is the active group of the degradation agent; R1-(A1)-R3-B1- and (R2S)-B2- are initial polymer molecular fragments formed after the initial polymer chain is broken, -A1- is a group formed after the degradation reaction of the chain-breaking group A, -B1- and -B2- are respectively active groups formed by the active end group B of the degradation agent at the two ends of the broken molecular chain, and the initial polymer molecular fragments R1-(A1C)-R3-B1- and (CR2S)-B2- with the chain-extending group C can achieve molecular chain growth and / or cross-linking through the reaction of the chain-extending group C with other groups or the mutual reaction between the chain-extending groups C to prepare a modified polymer.

[0147] On the other hand, the present invention can also provide a method for obtaining a modified polymer by subjecting the resin intermediate prepared by any of the above methods to a grafting reaction treatment, wherein the modified polymer is obtained by treating the initial polymer, and the treatment comprises the following steps:

[0148] C: After step A, the obtained resin intermediate is subjected to a grafting reaction with a grafting agent having both a grafting group and a chain extending group to prepare a modified polymer containing molecular fragments of the initial polymer and a chain extending group as a modified resin.

[0149] Furthermore, the grafting group is a functional group that can react with the active end group in the resin intermediate, and the chain extension group is a functional group that can react with other groups or react with each other.

[0150] Further, the production of the modified polymer includes the following reaction: R1-A-(R2S)+(R3)-B-→R1-(A1)-R3-B1-+(R2S)-B2-+(R4D)-C-→R1-(A1)-R3-(B1DR4)-C-+(R2S)-(B2DR4)-C-

[0151] Among them, -R1-A-(R2S)- is the initial polymer, A is the chain-breaking group, S is the side group, R3-B- is the degradant, and -B- is the active group of the degradant; R1-(A1)-R3-B1- and (R2S)-B2- are initial polymer molecular fragments formed after the initial polymer chain breaks, -A1- is the group formed after the degradation reaction of the chain-breaking group A, -B1- and -B2- are respectively active groups formed by the active end group B of the degradant at the two ends of the broken molecular chain, and the active groups A1 or B1 or B2 participate in subsequent reactions.

[0152] (R4D)-C- is a grafting agent, and D is a grafting group, which is used to react with the active groups A1, B1, and B2 in the resin intermediate to connect the initial polymer molecular fragments in the resin intermediate to the grafting agent molecules with the chain extender C, so that these initial polymer molecular fragments can be reconnected through the chain growth and / or cross-linking reaction of the chain extender group C to prepare a modified polymer; C is a chain extender group, and D can be a side group or on the main chain, and can be connected to a direct grafting group or a chain extender group, or it can be not connected to a grafting group or a chain extender group.

[0153] According to any of the above methods for obtaining a modified polymer resin by grafting reaction, the present invention further provides the following preferred embodiments.

[0154] Furthermore, the degradation reaction includes an esterification reaction, an ester exchange reaction, an aminolysis reaction or a hydrolysis reaction, and the grafting reaction includes an esterification reaction, an acylation reaction or an ester exchange reaction.

[0155] Preferably, the esterification reaction comprises direct esterification of an acid with an alcohol or phenol, comprising the following reaction:

[0156] Wherein, R′ can be aliphatic or aromatic, i.e., alcohol or phenol, and R″COZ is an acylating agent, wherein Z can represent -OH, -X, -OR, -OCOR, -NHR, etc. R′ and R″ in the resulting carboxylate molecule can be the same or different.

[0157] Preferably, the esterification reaction can also be the esterification of an acid derivative with an alcohol. The esterification of an acid derivative with an alcohol mainly includes the reaction of an alcohol with an acyl chloride, an alcohol with an acid anhydride, an alcohol with a carboxylate, etc. The equation is as follows: R′OH+R″COCl→R″COOR′+HCl R′X+R″COOM→R″COOR+MX

[0158] Preferably, the transesterification reaction mainly includes the exchange reaction between ester and alcohol, ester and acid, and ester and ester, and the chemical equation is as follows:

[0159] Preferably, the esterification reaction also includes other esterification reactions, including esterification of ketene and alcohol, alcoholysis of nitrile, alcoholysis of amide, and reaction of ether and carbon monoxide to synthesize ester. For example: ROH+CH2=CO→CH3COOR CH3O CH3+CO→CH3COOCH3

[0160] Furthermore, in step A, the initial polymer is a polyurethane, including thermoplastic polyurethane (TPU) having a linear or branched molecular structure and thermosetting polyurethane having a cross-linked network molecular structure. The polyurethane's molecular backbone contains carbamate groups, and the degradation agent contains hydroxyl groups. During the degradation reaction, the hydroxyl groups react with the carbamate groups and break at least a portion of the carbamate bonds on the initial polymer molecular chain, generating linear or branched molecular chain fragments containing carbamate groups and / or hydroxyl groups.

[0161] Furthermore, the initial polymer molecular chain has chain-breaking groups, including -N(H)n-, -NH-(CO)-O-, -HN-(CO)-NH-, The degradation reaction includes one or more combinations of alcoholysis, alkaline hydrolysis, hydrolysis, aminolysis, thermal decomposition or acidolysis; the degradation agent includes one or more combinations of polyols, alkaline solutions, water, ammonia water, acids, acid anhydrides, carboxylates, carboxylates, polar or non-polar solvents.

[0162] Furthermore, in step C, the grafting group includes a combination of one or more of an amide group, an amine group, a urea group, a hydroxyl group, a carboxyl group, an acid anhydride group or an epoxy group, and the chain extension group includes a combination of one or more of an amide group, an urea group, an amine group, a hydroxyl group, a carboxyl group, a carboxylate group, an unsaturated double bond, an ester group, an epoxy group or an aldehyde group.

[0163] Furthermore, the solvent is selected from one or a combination of formamide, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, trifluoroacetic acid, acetonitrile, hexamethylphosphoramide, cyclohexane, dichloromethane, pyridine, furan, chloroform, toluene, tetramethylethylenediamine or N-methylpyrrolidone;

[0164] Preferably, in the esterification reaction of step A, the acid is a linear carboxylic acid, preferably the hydroxyl group is a primary hydroxyl group, and preferably, a catalyst is used to accelerate the esterification reaction or reduce the reaction temperature. The catalyst includes a strong acid. The strong acid catalyst can reduce the activation energy of the reaction and thus accelerate the reaction. The reaction includes the following acyloxy bond cleavage mechanism:

[0165] Strong acid catalysts include concentrated sulfuric acid, dry hydrogen chloride, p-toluenesulfonic acid, methanesulfonic acid, sulfonic acid type cation exchange resin, solid acid, dicyclohexylcarbodiimide or tetrachloroaluminum ether complex, etc. Preferably, the strong acid catalyst is p-toluenesulfonic acid, sulfonic acid type cation exchange resin, dicyclohexylcarbodiimide or tetrachloroaluminum ether complex.

[0166] Preferably, the esterification reaction includes a water removal step, including physical and chemical methods. The physical method can be azeotropic distillation, that is, adding a water-immiscible solvent such as one or more of benzene, toluene, xylene, chloroform, and carbon tetrachloride to the reaction system (acid, alcohol, catalyst), performing distillation, and removing water by fractionation. Chemical dehydration methods include using anhydrous salts to absorb the water generated by the reaction. Anhydrous salts include copper sulfate, anhydrous hydrogen chloride, acetyl chloride, thionyl chloride, chlorosulfonic acid, carbodiimide (RN=C=NR), or boron trifluoride and its ether complex.

[0167] Furthermore, the esterification reaction in step A also includes a reaction between an acid anhydride and an alcohol or phenol. The acid anhydride includes acetic anhydride and maleic anhydride. Preferably, a small amount of an acidic or alkaline catalyst is added to the reaction to accelerate the reaction. Preferably, the catalyst includes sulfuric acid, perchloric acid, zinc chloride, ferric chloride, pyridine, anhydrous sodium ethanol, p-toluenesulfonic acid or a tertiary amine. The catalytic effect of a strong acid may be that the hydrogen proton first reacts with the acid anhydride to form an acyl cation with strong acylation ability. The catalytic effect of pyridine is generally believed to be that pyridine forms an active complex with the acid anhydride, which includes the following mechanisms: RC + O+R1OH→RCOOR1+H +

[0168] Furthermore, the esterification reaction in step A also includes a reaction between an acyl chloride and an alcohol or phenol, and the reaction mechanism includes: R′OH+R″COCl→R″COOR′+HCl

[0169] Preferably, hexamethylphosphoric acid triamide is used as a solvent or magnesium chips in the esterification reaction of step A;

[0170] Alternatively, it is not necessary to prepare the acid chloride first, and only the alcohol (phenol) and the acid are mixed, and thionyl chloride and phosphorus trichloride are added to react.

[0171] Preferably, N,N'-dimethylformamide (DMF) is added to the esterification reaction in step A, so that the reaction product SO2 or the remaining strong acid is absorbed by DMF.

[0172] Preferably, N,N'-dimethylformamide (DMF) is added to the grafting reaction in step C. DMF prevents the molecular chains of the product obtained by the esterification reaction from agglomerating due to hydrogen bonds between molecules.

[0173] Further, in step A, the initial polyurethane is Y(BA) (b-a) X(AB) a Y, composed of the initial isocyanate XA a and initial polyol YB b The reaction generates; the degradation agent is MCc ; The degradation reaction includes the following reactions:

[0174] Further, in step C, the grafting agent is D d NE e ; The grafting reaction includes the following reactions:

[0175] Wherein, A is the isocyanate group in the initial polyurethane, B is the hydroxyl group in the initial polyurethane, (AB) is the carbamate group in the initial polyurethane; X is the initial isocyanate main chain; Y is the initial polyol main chain; M is the main chain of the degradation agent; C is the active group of the degradation agent, including hydroxyl, active hydrogen, amine, and alkali metal groups; the chain-breaking group of the initial polyurethane is (AB); N is the main chain of the grafting agent, which can participate in the molecular morphology modification of the cured polyurethane resin; D is a grafting group, which can react with (AC) and B to generate (ACD) and (BD) so that the initial polymer molecular fragments in the resin intermediate are connected to the grafting agent molecules with the chain extender E; E is a chain extender group, which can enable the initial polymer molecular fragments to be reconnected through chain growth and / or cross-linking reactions of the chain extender group E to prepare a modified polymer; a, b, c, d, and e are functional groups, respectively. The above is a typical degradation reaction mechanism, where a=2, b=3, c=1, d=1, and e=1. The degradation reactions of other a, b, c, d, and e functional combinations are similar and fall within the scope of protection of the present invention.

[0176] Furthermore, in step A, the initial polymer contains -R1NHCOOR2- units; the degradation agent includes a compound R3(OH)n having a hydroxyl group; and the degradation reaction includes the following reaction: -R1NHCOOR2-+R3(OH)n→-R1NHCOOR3(OH) (n-1) -+-R2OH

[0177] Furthermore, in step C, the chain extension group of the grafting agent includes an unsaturated double bond, and the grafting group of the grafting agent includes a carboxyl group or an acid anhydride group; the grafting reaction includes the following reaction: -R1NHCOOR3(OH) (n-1) -+-R2OH+R4-(C=C) a -(CR5) b -(COOH)m→-R1NHCOOR3O-(CO) -(CR5) b -(C=C) a -R4+R2-O-(CO)-(CR5) b -(C=C) a -R4+H2O

[0178] or -R1NHCOOR3(OH) (n-1)-+-R2OH+-R4-(C=C) a -(CR5) b -(CO)O(CO)-→-R1NHCOOR3O- (CO)-(CR5) b -(C=C) a -R4-+-R2-O-(CO)-(CR5) b -(C=C) a -R4-

[0179] Among them, -R2OH+R4-(C=C)a-(CR5)b-(COOH)m and R4-(C=C)a-(CR5)b-(CO)O(CO)- are grafting agents with grafting groups, and the grafting groups include carboxyl groups -(COOH)m or acid anhydride groups -(CO)O(CO)-. Preferably, a=1-6, which is the functionality of the unsaturated double bond functional group -(C=C)a- of the grafting agent. More preferably, b=0-6, which is the number of carbon atoms from the unsaturated double bond to the grafting group. -R4- and R5 are side groups of the grafting agent main chain, including H atoms, methyl groups and other organic groups. The grafting agent includes acrylates, methacrylates, acids with unsaturated double bonds, acid anhydrides or carboxylates.

[0180] Furthermore, in step A, the initial polymer contains -R1NHCOOR2- units; the degradation agent includes an acid, anhydride, or anhydride salt with an unsaturated double bond; and the degradation reaction comprises the following reaction: -R1NHCOOR2-+R4-(C=C) a -(CR5) b -(COOH)m→R1-NH-(CO)-(CR5) b -(C=C) a -R4+ R2-O-(CO)-(CR5) b -(C=C) a -R4+CO2

[0181] or -R1NHCOOR2-+-R4-(C=C) a -(CR5) b -(CO)O(CO)-→-R1NH-(CO)-(CR5) b -(C=C) a - R4-+-R2-O-(CO)-(CR5) b -(C=C) a -R4-+CO2

[0182] Wherein, R4-(C=C)a-(CR5)b-(COOH)m and R4-(C=C)a-(CR5)b-(CO)O(CO)- are grafting agents with grafting groups, including carboxyl groups -(COOH)m or acid anhydride groups -(CO)O(CO)-, a=1-6, representing the functionality of the unsaturated double bond functional group -(C=C)a- of the grafting agent, b=0-6, representing the number of carbon atoms from the unsaturated double bond to the grafting group, -R4- and R5 are side groups of the grafting agent backbone, including H atoms, methyl groups, and other organic groups. Grafting agents include acrylates, maleic anhydride, and esters, acids, anhydrides, or carboxylates with unsaturated double bonds.

[0183] Furthermore, in step C, when the initial polymer contains -R1NHCOOR2- units; the grafting agent includes an acid, anhydride, or anhydride salt with an unsaturated double bond; the grafting reaction also includes an amide condensation reaction, including the following reaction: -R-NH-R'+R4-(C=C) a -(CR5) b -(COOH)m→R-NR'-(CO)-(CR5) b -(C=C) a -R4

[0184] or -R-NH-R'+-R4-(C=C) a -(CR5) b -(CO)O(CO)-→R-NR'-(CO)-(CR5) b -(C=C) a -R4

[0185] Among them, R4-(C=C)a-(CR5)b-(COOH)m and R4-(C=C)a-(CR5)b-(CO)O(CO)- are grafting agents with grafting groups, including carboxyl groups -(COOH)m or anhydride groups -(CO)O(CO)-. a = 1 to 6 represents the functionality of the unsaturated double bond functional group -(C=C)a- carried by the grafting agent, and b = 0 to 6 represents the number of carbon atoms between the unsaturated double bond and the grafting group. -RN-R' represents an amine-containing compound, with R as the main chain and R' as a pendant group attached to the nitrogen atom, including an H atom, a methyl group, or other organic group. Grafting agents include acrylates, maleic anhydride, esters with unsaturated double bonds, acids, anhydrides, or carboxylates. The amide condensation reaction allows the grafting groups to react simultaneously with hydroxyl and amine groups, eliminating the need to separate and purify the amino compound and polyol in the resin intermediate.

[0186] On the other hand, the present invention claims protection for a modified polymer prepared by any of the above-mentioned methods through grafting reaction treatment.

[0187] The present invention also provides a method for preparing a modified polymer for a semi-cured material by mixing and treating the modified resin prepared by any of the above methods, wherein the modified polymer is obtained by treating the initial polymer, and the treatment comprises the following steps:

[0188] F: Add a curing agent to the modified polymer and mix them to prepare a semi-cured material.

[0189] Furthermore, the curing agent is a compound that can react with the chain extending group, or a compound that can induce the chain extending groups to react with each other. Furthermore, the reactive functional groups of the compound that react include one or a combination of free radical initiators, isocyanate groups, acid anhydrides, carboxyl groups, epoxy groups, amine groups, amide groups or aldehydes.

[0190] Furthermore, in step A, the initial polymer is polyurethane, including thermoplastic polyurethane TPU with a linear or branched molecular structure and thermosetting polyurethane with a cross-linked network molecular structure. The initial polymer molecular chain has chain-breaking groups, which include -N(H)n-, -NH-(CO)-O-, -HN-(CO)-NH-, The degradation reaction includes one or more combinations of alcoholysis, alkaline hydrolysis, hydrolysis, aminolysis, thermal decomposition or acidolysis; further, the degradation agent includes one or more combinations of polyols, alkaline solutions, water, ammonia water, acids, acid anhydrides, carboxylates, polar and non-polar solvents;

[0191] Preferably, in step C, the grafting group includes one or more combinations of amide groups, amine groups, urea groups, amino groups, hydroxyl groups, carboxyl groups, acid anhydrides, carboxylates or epoxy groups, and the chain extension group includes one or more combinations of amide groups, urea groups, amino groups, hydroxyl groups, carboxyl groups, unsaturated double bonds, ester groups, epoxy groups or aldehydes.

[0192] Preferably, in step C, the chain extending group comprises an unsaturated double bond.

[0193] Preferably, in step 1, the curing agent includes a thermosensitive curing agent, the thermosensitive curing agent includes a thermosensitive free radical initiator and a blocked isocyanate, and the thermosensitive free radical initiator includes a peroxide, a persulfide, a peroxycarbonate, a peroxyboric acid, an azo compound or other suitable free radical initiator that can initiate the curing of a double bond-containing compound.

[0194] More preferably, the free radical initiator includes tert-butyl peroxyisopropyl carbonate, methyl ethyl ketone peroxide, potassium persulfate, cumene hydroperoxide, dibenzoyl peroxide, tert-butyl perbenzoate or 2,4-di-tert-butyl peroxide isopropylbenzene.

[0195] Furthermore, in step 1, the modified polymer is heated to 50° C. to 180° C., and then a curing agent is added to reduce its viscosity and make the resin and the curing agent uniformly mixed.

[0196] Furthermore, the method further comprises the step G:

[0197] G: The semi-cured material obtained in step G is heated to 50-160° C. and impregnated with fibers and / or fillers to produce a reinforced or filled semi-cured material, wherein the fiber form includes one or a combination of fiber fabric, continuous fiber yarn, chopped fiber, lumped fiber, powdered fiber, and filler. Filling the reinforcing material (i.e., fiber) and filler with the modified polymer under heating conditions can help improve the impregnation quality of the reinforcing material with the modified polymer. The process of impregnating the fibers and fillers includes one or more combinations of methods such as high-speed stirring, centrifugal stirring, screw mixing, rubber roller kneading, stirring and kneading, forming a rubber film and composite rolling, diluting and then impregnating, and composite and then rolling.

[0198] Non-reinforced prepregs can be used to make films for bonding plates, sheets, honeycombs, foams, and other materials. The prepregs containing reinforcing or filling materials obtained in step g include composite prepregs, sheet molding compounds (SMC), and bulk molding compounds (BMC). The manufacturing process used can be selected from the equipment and processes for manufacturing composite prepregs, sheet molding compounds (SMC), and bulk molding compounds (BMC). Reference can be made to "Composite Material Molding Technology and Application" (edited by Xu Zhu, published by National Defense Industry Press). The fiber materials used include metal fibers, non-metallic fibers, polymer fibers, and natural fibers, including steel fibers, aluminum fibers, copper fibers, glass fibers, basalt fibers, ceramic fibers, alumina fibers, carbon fibers, polyester fibers, nylon fibers, polyvinyl alcohol fibers, ultra-high molecular weight polyethylene fibers, polypropylene fibers, spandex, bamboo fibers, hemp fibers, palm fibers, cotton fibers, and silk. Preferably, the weight ratio of fiber to modified resin is 0-0.1:1, 0.1-0.25:1, 0.25-0.4:1, 0.4-0.8:1, 0.8-1:1, 1.5:1, 1.5-2:1, 2-3:1, 3-4:1, 4-6:1 or 6-8:1; the semi-cured material obtained in step g of the present invention can further enhance its mechanical properties, and can be used to manufacture composite materials according to traditional composite material semi-cured material molding processes and equipment, including prepreg composite material manufacturing processes, sheet molding compound composite material manufacturing processes, and bulk molding compound composite material manufacturing processes. In addition, forming processes including hand lay-up, injection, vacuum infusion, RTM, winding, pultrusion, molding, continuous plate, etc. can be used, and the forming pressure is 0.05~0.1MPa, 0.1~0.5MPa, 0.5~1MPa, 1~2MPa, 2~5MPa, 5~10MPa, 10~20MPa, 20~30MPa or 30~50MPa.

[0199] Furthermore, in step H or step G, a cooling step is included, wherein the semi-cured material is cooled to below 50° C. for storage, preferably, cooled to below 35° C. for storage.

[0200] On the other hand, the present invention claims protection for a modified polymer prepared as a semi-cured material by any one of the above mixing methods.

[0201] As another embodiment, the present invention also provides a method for preparing a modified polymer of a cured resin by subjecting the modified resin or semi-cured material prepared by any of the above methods to a curing reaction, wherein the modified polymer is obtained by treating the initial polymer, and the treatment comprises the following steps:

[0202] Step E: Impregnating the modified polymer into fibers at 0-150° C. to produce a composite material, wherein the fibers include one or a combination of fiber fabrics, continuous fiber yarns, chopped fibers, pelletized fibers, powdered fibers, or fillers.

[0203] Step (i): Add a curing agent to the composite material to carry out a curing reaction to obtain a cured resin.

[0204] Furthermore, the curing agent comprises a compound capable of reacting with a chain extender group, or a compound capable of initiating a reaction between the chain extenders. Furthermore, the curing agent molecule must contain at least two or more chain extender-reactive functional groups to achieve chain extension and curing of the modified polymer. Chain extender-reactive functional groups include, but are not limited to, free radical initiators, isocyanate groups, acid anhydrides, carboxyl groups, epoxy groups, amine groups, and amide groups.

[0205] Furthermore, in step 1, the added curing agent also includes an accelerator compatible with the free radical initiator to promote the initiator to generate free radicals. The accelerator includes a metal salt, an organic amine, including a cobalt salt, a copper salt, a zinc salt, or an aniline accelerator. The addition of the accelerator can lower the initiation temperature of the initiator and improve the initiation efficiency of the initiator, thereby achieving low-temperature curing of the modified resin or rapid curing of the modified resin.

[0206] Preferably, in step 1, the curing agent includes a thermosensitive curing agent, the thermosensitive curing agent includes a thermosensitive free radical initiator and a blocked isocyanate, and the thermosensitive free radical initiator includes a peroxide, a persulfide, a peroxycarbonate, a peroxyboric acid, an azo compound or other suitable free radical initiator that can initiate the curing of a double bond-containing compound.

[0207] More preferably, the free radical initiator includes tert-butyl peroxyisopropyl carbonate, methyl ethyl ketone peroxide, potassium persulfate, cumene hydroperoxide, dibenzoyl peroxide, tert-butyl perbenzoate or 2,4-di-tert-butyl peroxide isopropylbenzene.

[0208] Furthermore, in step A, the initial polymer is a polyurethane, including thermoplastic polyurethane TPU with a linear or branched molecular structure and thermosetting polyurethane with a cross-linked network molecular structure. The main chain of the molecule contains a carbamate group, and the degradation agent contains a hydroxyl group. In the degradation reaction, the hydroxyl group reacts with the carbamate group and opens at least a portion of the carbamate bond on the initial polymer molecular chain to generate a molecular chain fragment with a linear or branched molecular structure containing carbamate groups and / or hydroxyl groups. The initial polymer molecular chain carries a chain-breaking group, and the chain-breaking group includes -N(H)n-, -NH-(CO)-O-, -HN-(CO)-NH-, The degradation reaction includes one or more combinations of alcoholysis, alkaline hydrolysis, hydrolysis, aminolysis, thermal decomposition or acidolysis; the degradation agent includes one or more combinations of polyols, alkaline solutions, water, ammonia water, acids, acid anhydrides, carboxylates, polar and non-polar solvents;

[0209] Preferably, in step C, the grafting group includes one or more combinations of amide groups, amine groups, urea groups, amino groups, hydroxyl groups, carboxyl groups, acid anhydrides, carboxylates or epoxy groups, and the chain extension group includes one or more combinations of amide groups, urea groups, amino groups, hydroxyl groups, carboxyl groups, unsaturated double bonds, ester groups, epoxy groups or aldehydes.

[0210] Preferably, in step A, the initial polymer is a polyurethane, the main molecular chain of which contains carbamate groups, and the degradation agent contains hydroxyl groups. In the degradation reaction, the hydroxyl groups react with the carbamate groups and open at least a portion of the carbamate bonds on the initial polymer molecular chain to generate molecular chain fragments with a linear or branched molecular structure containing carbamate groups and / or hydroxyl groups.

[0211] Preferably, in step C, the chain extending group comprises an unsaturated double bond.

[0212] According to any of the above methods for performing a curing reaction to obtain a modified polymer resin, the present invention further provides the following preferred embodiments.

[0213] Further, the process of the curing reaction is as follows:

[0214] Further, the process of the curing reaction is as follows:

[0215] Among them, the grafting agent is D d NE eA is the isocyanate group in the initial polyurethane, B is the hydroxyl group in the initial polyurethane, and (AB) is the carbamate group in the initial polyurethane; X is the initial isocyanate main chain; Y is the initial polyol main chain; M is the degradant main chain; C is the active group of the degradant, including hydroxyl, active hydrogen, amine, and alkali metal groups; the chain-breaking group of the initial polyurethane is (AB); N is the main chain of the grafting agent, which can participate in the molecular morphology modification of the cured polyurethane resin; D is a grafting group, which can react with (AC) and B to generate (ACD) and (BD) so that the initial polymer molecular fragments in the resin intermediate are connected to the grafting agent molecules with the chain extender E; E is a chain extender group, which can enable the initial polymer molecular fragments to be reconnected through the chain growth and / or cross-linking reaction of the chain extender group E to obtain a modified polymer; a, b, c, d, and e are functional groups, respectively.

[0216] As another embodiment, the process of the curing reaction is as follows:

[0217] Among them, A is the isocyanate group in the initial polyurethane, B is the hydroxyl group in the initial polyurethane, (AB) is the carbamate group in the initial polyurethane; X is the initial isocyanate backbone; Y is the initial polyol backbone; M is the degradation agent backbone; C is the active group of the degradation agent, including hydroxyl, active hydrogen, amine, and alkali metal groups; Y(AB)(ba)X(AC)aM(a-c+1) is a carbamate-based polyol; Y(B)a is a recycled polyol; (AC) is the active end group generated by the active group of the degradation agent and one side of the carbamate group; D is a grafting group that can react with (AC) and B; E is a chain extending group that can extend or cross-link the polyurethane resin molecules to form a cured polyurethane resin; N is the backbone of the grafting agent, which can participate in the molecular morphology modification of the cured polyurethane resin; a, b, c, d, and e are functional groups, respectively.

[0218] Furthermore, in step A, the following reaction is included: -R1NHCOOR2-+R3(OH)n→-R1NHCOOR3(OH) (n-1) -+-R2OH

[0219] Furthermore, in step C, the following reaction is included: -R1NHCOOR3(OH) (n-1) -+-R2OH+R4-(C=C) a -(CR5) b -(COOH)m→-R1NHCOOR3O-(CO) -(CR5) b -(C=C) a -R4+R2-O-(CO)-(CR5) b -(C=C) a -R4+H2O

[0220] or -R1NHCOOR3(OH) (n-D -+-R2OH+-R4-(C=C) a -(CR5) b -(CO)O(CO)-→-R1NHCOOR3O- (Co)-(CR5) b -(C=C) a -R4-+-R2-O-(CO)-(CR5) b -(C=C) a -R4-

[0221] In step 1, the free radical initiator generates active free radicals to open the unsaturated double bonds to form free radicals to initiate the crosslinking and curing reaction between the unsaturated double bonds.

[0222] Specifically, it includes the following reaction: -R1NHCOOR3O-(CO)-(CR5) b -(C=C) a -R4-+-R2-O-(CO)-(CR5) b -(C=C) a -R4-+M1- O-OM2 (heating or accelerator initiation) → -R1NHCOOR3O-(CO)-(CR5) b -(C M1-C) a -R4- -R2-O-(CO)-(CR5) b -(C M2-C) a -R4-→

[0223] M1-OO-M2 is a peroxidation initiator, which generates free radicals under heating conditions or catalytic conditions of a promoter, and reacts with unsaturated double bonds to form chain growth points at the unsaturated double bonds.

[0224] In another embodiment, in step C, the initial polymer contains -R1NHCOOR2- units; the grafting agent includes esters, acids, anhydrides, and carboxylates with unsaturated double bonds; and the grafting reaction further includes an amide condensation reaction, including the following reaction: -R-NH-R'+R4-(C=C) a -(CR5) b -(COOH)m→R-NR'-(CO)-(CR5) b -(C=C) a -R4

[0225] or -R-NH-R'+-R4-(C=C) a -(CR5) b-(CO)O(CO)-→R-NR'-(CO)-(CR5) b -(C=C) a -R4

[0226] Furthermore, in step 1, the free radical initiator generates active free radicals to open the unsaturated double bonds to form free radicals to initiate a crosslinking and curing reaction between the unsaturated double bonds.

[0227] Specifically, it includes the following reaction: R-NR'-(CO)-(CR5) b -(C=C) a -R or R-NR'-(CO)-(CR5) b -(C=C) a -R4+M1-O-OM2 (heating or accelerator initiation) → R-NR'-(CO)-(CR5) b -(CC) a -R4 or R-NR'-(CO)-(CR5) b -(CC) a -R4→

[0228] or

[0229] M1-OO-M2 is a peroxidation initiator, which generates free radicals under heating conditions or catalytic conditions of a promoter, and reacts with unsaturated double bonds to form chain growth points at the unsaturated double bonds.

[0230] On the other hand, the present invention claims protection for a modified polymer prepared by any of the above methods through a curing reaction treatment.

[0231] According to any one of the above methods for preparing a modified polymer, the present invention further provides the following preferred embodiments.

[0232] As a preferred embodiment, the resin intermediate, modified polymer, semi-cured material and cured resin do not contain isocyanate groups, so that the prepared resin intermediate, modified polymer, semi-cured material and cured resin can be stored for a long time and the toxicity of the product is reduced.

[0233] As a preferred embodiment, the curing agent does not contain compounds containing isocyanate groups to prevent premature curing and hardening of the semi-cured material and foaming of the cured resin, thereby extending the process operation time. The production process operation time of the resin intermediate, modified polymer, semi-cured material, and cured resin is not less than 5 minutes, preferably, not less than 30 minutes, more preferably, not less than 2 hours, more preferably, not less than 4 hours, more preferably, not less than 8 hours, more preferably, not less than 12 hours, and more preferably, not less than 24 hours.

[0234] As a preferred embodiment, the semi-cured material can be stored at 25°C for not less than 4 hours, preferably, not less than 24 hours, more preferably, not less than 3 days, more preferably, not less than 7 days, more preferably, not less than 21 days, more preferably, not less than 1 month, more preferably, not less than 2 months, more preferably, not less than 3 months, more preferably, not less than 6 months, more preferably, not less than 12 months.

[0235] As a preferred embodiment, step A further comprises the following steps:

[0236] Step B: removing and recovering excess degradation agent from the resin intermediate obtained in step A. Furthermore, the removal method includes one or more combinations of reduced pressure distillation, thin film evaporation, extraction purification, fractionation, rectification, and precipitation.

[0237] As a preferred embodiment, the step C further includes the following steps:

[0238] Step D: Filter, remove impurities, and dry the modified resin obtained in Step C. Furthermore, the filtration method includes press filtration and vacuum filtration; the impurity removal method includes one or more combinations of extraction purification, fractionation, rectification, and precipitation; and the drying method includes one or more combinations of ultrasonic, microwave, heating, and vacuum-assisted drying methods.

[0239] As a preferred embodiment, in step A, the degradation reaction includes one or more of alcoholysis reaction, alcohol-alkali reaction, alkaline hydrolysis reaction, hydrolysis reaction, aminolysis reaction or thermal decomposition reaction.

[0240] As a preferred embodiment, the degradation agent is an alcoholysis agent, and the alcoholysis agent includes a single molecule, oligomer or polymer with 1 to 6 hydroxyl groups.

[0241] As a preferred embodiment, the degradation agent is an alcoholysis agent which is a polyol with a functionality of 2 to 6 and a main chain containing 2 to 10 methylene groups.

[0242] As a preferred embodiment, the degradation agent is an alcoholysis agent which is a polyol with a functionality of 2-4, a main chain containing 2 to 6 methylene groups and an ether bond, which can improve the toughness of the polyurethane while maintaining its strength.

[0243] As a preferred embodiment, the degradation agent includes one or more selected from 1,2-propylene glycol, ethylene glycol, butanediol, pentanediol, hexanediol, diethylene glycol, 1,6-hexanediol, polyether polyols with a molecular weight of less than 700, or polyether polyols with a molecular weight of greater than 800. Preferably, the degradation agent is selected from ethylene glycol, diethylene glycol, dipropylene glycol, or glycerol, and has a molecular weight of 200-700 and a functionality of 2-4. This can produce a homogeneous resin intermediate that can be used directly without separation or purification.

[0244] As a preferred embodiment, the active end groups in the resin intermediate include one or more of amide groups, urea groups, amine groups, hydroxyl groups, carboxyl groups, unsaturated double bonds, ester groups or epoxy groups.

[0245] As a preferred embodiment, the grafting agent contains unsaturated double bonds and compounds including but not limited to one or more of amide groups, amine groups, urea groups, amino groups, hydroxyl groups, carboxyl groups, acid anhydrides, and epoxy groups.

[0246] As a preferred embodiment, the free radical initiator includes but is not limited to a peroxide initiator and a accelerator thereof.

[0247] As a preferred embodiment, the initial polymer comprises one or more cured polyurethanes, and the cured polyurethanes comprise polyurethane waste.

[0248] As another preferred embodiment, the resin intermediate is compounded from different polymer resin intermediates made from different initial polymers.

[0249] Preferably, the initial polymer accounts for no less than 20% of the resin intermediate, more preferably no less than 40%, more preferably no less than 60%, more preferably no less than 70%, more preferably no less than 80%, which can reduce costs and improve the elongation at break of the modified resin.

[0250] As a preferred embodiment, the number average molecular weight of the resin intermediate measured by RID and VWD (254 nm) detectors is 150-200; 200-350; 350-700; 700-1000, 700-1000, 1000-1800, 1800-3000, 3000-5000, 5000-10000, 10000-30000 or 30000-60000 g / mol.

[0251] As a preferred embodiment, the hydroxyl value of the modified resin is 0-50, 50-100, 100-200, 200-500 or 500-800 mgKOH / g.

[0252] As a preferred embodiment, the acid value of the modified resin is 0-8, 8-16, 16-30, 30-100 or 100-200 mgkoH / g.

[0253] As a preferred embodiment, the amine value of the modified resin is 0-20, 20-40, 40-80 or 80-150 mg KOH / g.

[0254] As a preferred embodiment, the amine value of the resin intermediate is 0-20, 20-30, 30-40, 40-60, 60-80, 80-120, 120-150, 150-180, 180-200, 200-230, 230-280 or 280-500 mg KOH / g.

[0255] As a preferred embodiment, an infrared spectrometer is used to measure the infrared spectrum of the resin intermediate or modified resin at 1690 cm-1 to 1780 cm-1. -1 There is an absorption peak at , which can confirm that the resin intermediate or modified resin contains carbamate functional groups.

[0256] In a preferred embodiment, in the grafting reaction, the chain-extending groups of the grafting agent include unsaturated double bonds, and the grafting groups are selected from one or more of amide, urea, hydroxyl, carboxyl, anhydride, or epoxy groups. Because the unsaturated bonds can react with each other without introducing new polar groups, they have minimal impact on the initial polymer chain and are relatively easy to control when adjusting the modified polymer chain. Furthermore, the unsaturated double bonds are initiated by an initiator, and the resin remains unreactive below the initiator's initiation temperature, enabling long-term storage and operation. Once the initiator's initiation temperature is reached, the resin rapidly cures, further improving the curing efficiency of the resin.

[0257] As a preferred embodiment, in the grafting reaction, the grafting agent includes one or more selected from acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, mono-2-(acryloyloxy)ethyl phthalate, mono-2-(methacryloyloxy)ethyl phthalate, N-(carboxyphenyl)maleimide, N-(carboxyphenyl)methacrylamide, N-(carboxyphenyl)acrylamide or methacryloyl chloride. These grafting groups can effectively react with the active terminal hydroxyl groups and / or amine groups on the resin intermediate.

[0258] As a preferred embodiment, in the degradation reaction, the total mass of the degradation agent is 0.5-10 times that of the initial polymer. This range of degradation agent can achieve the reaction without causing too much workload for the subsequent vacuum distillation.

[0259] As a preferred embodiment, the total mass of the unsaturated carboxylic acid or unsaturated carboxylic anhydride used as the grafting agent is 0.2-10 times that of the polymer resin intermediate, thereby achieving a higher reaction yield.

[0260] In a preferred embodiment, during the reaction between the grafting agent and the resin intermediate, the ratio of the total number of moles of carboxylic acid / carboxylic anhydride of the unsaturated carboxylic acid or unsaturated carboxylic anhydride serving as the grafting agent to the number of moles of hydroxyl groups in the resin intermediate is 0.8-1.2. In this case, the unsaturated carboxylic acid reacts substantially completely with the hydroxyl groups in the resin intermediate, eliminating the need for vacuum distillation to remove excess acid, anhydride, or carboxylate, thereby reducing the number of process steps.

[0261] As a preferred embodiment, the modified resin is blended with a reactive diluent having an unsaturated double bond or an unsaturated resin. The reactive diluent includes one or more of styrene, methacrylate, hydroxyacrylate, polyol or acrylate; the unsaturated resin includes unsaturated polyester resin, acrylic resin, vinyl resin, etc., among which representative substances include but are not limited to methyl methacrylate, isobornyl methacrylate, isooctyl acrylate, cyclohexane acrylate, decyl methacrylate, 2-ethylhexyl methacrylate, dihydrocyclopentadiene acrylate, ethoxylated phenoxyethyl acrylate, hydroxypropyl methacrylate, ethylene glycol diacrylate, propylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1.6-hexanediol diacrylate, cyclohexane dimethacrylate, diallyl phthalate, diethylene glycol dimethacrylate, tripropylene glycol diacrylate, hydroxybutyl acrylate, pentaerythritol tetraacrylate, pentaerythritol trimethacrylate, glycerol triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane trimethacrylate or glycerol diacrylate, etc., which can adjust the viscosity and properties of the modified resin.

[0262] As a preferred embodiment, it can be used to prepare composite materials by various other composite material processes, including pultrusion, winding, infusion, hand lay-up, spraying, RTM, etc.

[0263] As a preferred embodiment, the semi-cured material can be stored at 25°C for not less than 4 hours, preferably, not less than 24 hours, more preferably, not less than 3 days, more preferably, not less than 7 days, more preferably, not less than 21 days, more preferably, not less than 1 month, more preferably, not less than 2 months, more preferably, not less than 3 months, more preferably, not less than 6 months, more preferably, not less than 12 months.

[0264] As a preferred embodiment, the curing agent used to cure the modified resin includes a free radical initiator, and the free radical initiator includes but is not limited to a peroxide initiator and an accelerator thereof.

[0265] In a preferred embodiment, the initial polymer comprises one or more cured polyurethanes. The cured polyurethanes may comprise polyurethane waste, or the modified resin may be a composite of different resins made from different initial polymers. Preferably, the initial polymer accounts for no less than 20% of the modified resin, more preferably no less than 40%. More preferably, no less than 60%, and even more preferably, no less than 70%, thereby reducing costs and improving the properties of the modified resin, such as elongation at break.

[0266] As a preferred embodiment, the initial polymer comprises one or more cured polyurethanes, and the cured polyurethanes comprise polyurethane waste.

[0267] As a preferred embodiment, the initial polymer resin can be obtained from a wide range of sources. It can not only be prepared by direct curing of black and white materials, but can also be obtained from polyurethane waste, such as the insulation rigid foam commonly used in refrigerators and containers, polyurethane soft foam used in mattresses and sofas, polyurethane elastomer screens used in mines, polyurethane elastomer rollers, etc. The use of polyurethane waste not only reduces the cost of new polyurethane but also increases the utilization value of polyurethane waste, helping to improve the recycling level of polyurethane. The present invention is applied to the recycling of polyurethane and can solve key technical problems in existing polyurethane recycling. Because existing polyurethane recycling technology must convert the initial polymer into standard chemical raw materials to produce polyurethane that meets performance requirements, this requires complex decomposition and purification steps, which are technically complex, energy-intensive, and cause byproduct pollution. The present technology does not require these steps.

[0268] As a preferred embodiment, the tensile strength of the modified polymer is not less than 20 MPa, not less than 35 MPa, not less than 50 MPa, preferably, the tensile strength is not less than 60 MPa, more preferably, the tensile strength is not less than 70 MPa.

[0269] As a preferred embodiment, the modified polymer has a flexural strength of not less than 30 MPa, not less than 45 MPa, preferably, not less than 55 MPa, more preferably, a flexural strength of not less than 65 MPa, more preferably, a flexural strength of not less than 75 MPa, more preferably, a flexural strength of not less than 85 MPa, more preferably, a flexural strength of not less than 95 MPa, more preferably, a flexural strength of not less than 105 MPa, more preferably, a flexural strength of not less than 120 MPa.

[0270] As a preferred embodiment, the elongation at break of the modified polymer is not less than 2%, preferably, the elongation at break is not less than 3%, more preferably, the elongation at break is not less than 4%, more preferably, the elongation at break is not less than 5%, more preferably, the elongation at break is not less than 20%, more preferably, the elongation at break is not less than 50%, more preferably, the elongation at break is not less than 100%, more preferably, the elongation at break is not less than 150%.

[0271] As a preferred embodiment, the heating methods used in the degradation reaction and / or grafting reaction include microwave heating, ultrasonic heating, and electromagnetic heating. Preferably, microwave-absorbing materials are added to the reaction materials during the microwave heating reaction. Microwave-absorbing materials include ferrite powder, carbonyl iron powder, silicon carbide powder, silicon carbide fiber, and composite ferrite. These materials rapidly convert microwaves into heat energy during microwave heating, thereby improving reaction efficiency.

[0272] As a preferred embodiment, the degradation reaction and / or grafting reaction is carried out using a microchannel reactor, which can improve the reaction efficiency and reduce the reaction safety risk.

[0273] In another aspect, the present invention claims a modified polymer resin prepared by any one of the above methods.

[0274] The present invention discloses a modified polyurethane and a method for manufacturing the same. A portion of an initial polyurethane molecular chain is opened to form a resin intermediate containing initial polyurethane molecular fragments with active groups or containing initial polyurethane molecular fragments with chain extension groups. The resin intermediate is then transformed into a liquid modified polyurethane resin containing initial polyurethane molecular fragments with active double bond groups through a grafting reaction. The modified polyurethane resin is then cured to form a plate-cured material, or the modified polyurethane is mixed with reinforcing materials such as fillers or fibers and then cured to form a composite material based on a thermosetting modified polyurethane resin. In this process, the molecular weight and molecular structure of the initial polyurethane are adjusted by designing and controlling the chemical reaction, and additives are designed and controlled to obtain a modified polyurethane with target properties, a semi-cured material serving as a thermosetting modified polyurethane resin, and a composite material based on the resin.

[0275] The present invention has found that only a portion of the energy of the existing polyurethane degradation method is needed to open a portion of the polyurethane molecular chain to convert it into a polymer resin intermediate, and then the resin intermediate is finally subjected to a grafting reaction to become a liquid modified polyurethane resin. During this process, the molecular weight and molecular structure of the initial polyurethane are adjusted to meet the performance requirements of the use environment for the polyurethane.

[0276] The present invention provides a modified polyurethane, a semi-cured material, a composite material and a preparation method thereof. By designing and adjusting the chemical reactions in each production step, a cured initial polyurethane is reacted with a degradation agent to prepare a resin intermediate with an active end group. A reactant and a cross-linking group, specifically an unsaturated carboxylic acid or an unsaturated carboxylic anhydride as a grafting agent, are introduced to react with the active end group to prepare a modified polyurethane with a chain extension or cross-linking reaction group, i.e., an unsaturated double bond. A free radical initiator is added to initiate a mutual reaction of the unsaturated double bonds in the modified polyurethane to cause molecular chain extension and cross-linking curing reactions to obtain a cured polyurethane resin as the semi-cured material. The use of isocyanate directly involved in the reaction to produce the polyurethane is reduced or avoided, thereby avoiding the water sensitivity and high activity of the isocyanate group that causes the resin to foam and gel prematurely, and extending the resin's process life. The modified polyurethane, as a composite material processing raw material, can be adapted to conventional composite material processing techniques, whereas conventional polyurethane resins require complex equipment to produce composite materials. Furthermore, the present invention can optimize the molecular structure of the initial polyurethane, thereby significantly improving the comprehensive mechanical properties of the cured polyurethane resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0277] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0278] FIG1 is a CJ-3-56 infrared spectrum of the third comparative example Beta-1;

[0279] FIG2 is a CJ-3-1 infrared spectrum of Example Beta-E1 of the third part;

[0280] FIG3 is a CJ-3-2 infrared spectrum of Example Beta-E1 of the third part;

[0281] FIG4 is a CJ-3-3 infrared spectrum of Example Beta-E1 of the third part;

[0282] FIG5 is a CJ-3-4 infrared spectrum of Example Beta-E1 of the third part;

[0283] FIG6 is a CJ-3-5 infrared spectrum of Example Beta-E1 of the third part;

[0284] FIG7 is a CJ-2-1 infrared spectrum of Beta-E2 of the third embodiment;

[0285] FIG8 is a CJ-2-2 infrared spectrum of Beta-E2 of the third embodiment;

[0286] FIG9 is a CJ-2-3 infrared spectrum of Beta-E2 of the third embodiment;

[0287] FIG10 is a CJ-2-4 infrared spectrum of Beta-E2 of the third embodiment;

[0288] FIG11 is a CJ-2-5 infrared spectrum of Beta-E2 of the third embodiment;

[0289] FIG12 is a CJ-2-6 infrared spectrum of Beta-E2 of the third embodiment;

[0290] FIG13a is a RID spectrum of CJ-3-1 of Beta-E1 of the third embodiment;

[0291] FIG13 b is a VWD spectrum of CJ-3-1 of Example Beta-E1 of the third part;

[0292] FIG14a is a RID spectrum of CJ-3-2 of Beta-E1 of the third embodiment;

[0293] FIG14 b is a VWD spectrum of CJ-3-2 of Beta-E1 of the third embodiment;

[0294] Figure 15a is the RID spectrum of CJ-3-3 of Beta-E1 of the third embodiment;

[0295] FIG15 b is a VWD spectrum of CJ-3-3 of Beta-E1 of the third embodiment;

[0296] Figure 16a is the RID spectrum of CJ-3-4 of Beta-E1 of the third embodiment;

[0297] FIG16 b is a VWD spectrum of CJ-3-4 of Beta-E1 of the third embodiment;

[0298] Figure 17a is the RID spectrum of CJ-3-5 of Beta-E1 of the third embodiment;

[0299] FIG17 b is a VWD spectrum of CJ-3-5 of Beta-E1 of the third embodiment;

[0300] FIG18a is a RID spectrum of CJ-2-1 of Beta-E2 of the third embodiment;

[0301] FIG18 b is a VWD spectrum of CJ-2-1 of Beta-E2 of the third embodiment;

[0302] FIG19a is a RID spectrum of CJ-2-2 of Beta-E2 of the third embodiment;

[0303] FIG19b is a VWD spectrum of CJ-2-2 of Beta-E2 of the third embodiment;

[0304] Figure 20a is the RID spectrum of CJ-2-3 of Beta-E2 of the third embodiment;

[0305] FIG20 b is a VWD spectrum of CJ-2-3 of Beta-E2 of the third embodiment;

[0306] Figure 21a is the RID spectrum of CJ-2-4 of Beta-E2 of the third embodiment;

[0307] FIG21 b is a VWD spectrum of CJ-2-4 of Beta-E2 of the third embodiment;

[0308] Figure 22a is the RID spectrum of CJ-2-5 of Beta-E2 of the third embodiment;

[0309] FIG22 b is a VWD spectrum of CJ-2-5 of Beta-E2 of the third embodiment;

[0310] Figure 23a is the RID spectrum of CJ-2-6 of Beta-E2 of the third embodiment;

[0311] Figure 23b is the VWD spectrum of CJ-2-6 of Beta-E2 of the third embodiment.

[0312] Figure 24a is the RID spectrum of JS-01B of the third comparative example Beta-3;

[0313] FIG24 b is a VWD spectrum of JS-01B of the third comparative example Beta-3;

[0314] FIG25 is a CJ-3-56 infrared spectrum of the second comparative example Alpha-1;

[0315] FIG26 is an infrared spectrum of JJ / CJ-3 / SJZH-2 of Example Gamma-1 of the fourth part;

[0316] FIG27 is a CJ35 / H12 infrared spectrum of Example Gamma-2 of the fourth part;

[0317] FIG28 is an MB1C infrared spectrum of Example Gamma-6 of the fourth part;

[0318] FIG29 is an infrared spectrum of MB1 of Example Gamma-7 of the fourth part;

[0319] FIG30 is a process flow chart of the seventh embodiment;

[0320] FIG31 is a schematic diagram of the internal mixer of the seventh section;

[0321] FIG32 is a side sectional view of the internal mixer of the seventh section;

[0322] FIG33 is a schematic diagram of the mixing rotor in the seventh section of the internal mixer;

[0323] FIG34 is a schematic diagram of the combination of the internal mixer and the screw extruder of the seventh part.

[0324] The description of the accompanying drawings is as follows:

[0325] Nitrogen tube: 1

[0326] Cooling water pipe: 2

[0327] Mixing plate: 3

[0328] Refining Chamber: 4

[0329] Mixing rotor: 5

[0330] Screw extruder: 6 DETAILED DESCRIPTION

[0331] The detailed features and advantages of this patent are described in detail below in the specific implementation method. The content is sufficient to enable any technical personnel in this field to understand the technical content of this patent and implement it accordingly. Based on the description and claims disclosed in this specification, technical personnel in this field can easily understand the relevant purposes and advantages of this patent.

[0332] In order to make the purpose, technical solutions and advantages of this patent clearer, the implementation methods of this patent will be further described in detail below.

[0333] Part I: Basic Example Group - Modified Polyurethane

[0334] Unless otherwise specified below, the polymer refers to a polyurethane polymer.

[0335] The raw materials used in this embodiment are commercially available. PMDI (trade name 44V20L) was purchased from Covestro; polyols NJ-303 and NJ-204 were purchased from Ningwu New Materials Company in Jurong; dibenzoyl peroxide was purchased from Nouryon; dicumyl peroxide (brand name PdBC-ff) was purchased from Nouryon; butanediol (BDO) and methacrylic acid (MAA) were purchased from Sinopharm Group; woven fabric (brand name EWR400) was purchased from Chongqing International Composite Materials Co., Ltd.; methyl ethyl ketone peroxide (MEKP), blue water (cobalt isooctanoate), and ethylene glycol diacrylate were purchased from Sinopharm Group; and a mold release agent (brand name Loctite 55-NC) was purchased from Henkel AG in Germany.

[0336] Comparative Example 1

[0337] At 25°C and 60% relative humidity, 100 grams of NJ-303 and 113 grams of PMDI were mixed and stirred for 30 seconds. The mixture was then poured into a mold preheated to 70°C in an oven. The oven temperature was then raised to 120°C over 20 minutes and maintained at this temperature for 30 minutes. The oven was then turned off to allow the polyurethane resin formed in the mold to cool naturally to room temperature. The mold was removed to obtain a solidified polyurethane resin plate.

[0338] Comparative Example 2

[0339] At 25°C and 60% relative humidity, 60g of NJ-303, 40g of NJ-204, and 95g of PMDI were mixed and stirred for 30 seconds. The mixture was then poured into a mold preheated to 70°C in an oven. The oven temperature was then raised to 120°C over 20 minutes and maintained for 30 minutes. The oven was then turned off to stop heating and the polyurethane resin formed in the mold was allowed to cool naturally to room temperature. The mold was removed to obtain a cured polyurethane resin plate.

[0340] Comparative Example 3

[0341] 90 g of NJ-303, 10 g of BDO, and 95 g of PMDI were mixed at 25°C and 60% relative humidity, stirred for 30 seconds, and poured into a mold preheated to 70°C in an oven. The oven temperature was then raised to 120°C over 20 minutes and maintained at this temperature for 30 minutes. The oven was then turned off to stop heating, and the polyurethane resin formed in the mold was allowed to cool naturally to room temperature. The mold was then removed to obtain a cured polyurethane resin sheet.

[0342] The polyurethane resin plates obtained in Comparative Examples 1-3 were observed for their appearance, and samples were cut and tested for their bending mechanical properties according to GB / T 2567-2008 Test Methods for Properties of Cast Resin Bodies.

[0343] Gel time: Mix all raw material components, stir for 30 seconds, and test the gel time according to the test standard "GB / T 7193-2008".

[0344] Table 1: Polyurethane resin reactivity, cured sheet quality and mechanical properties

[0345] As shown in Table 1, due to water sensitivity, the polyurethane resin sheets produced in Comparative Examples 1-3 all contained bubbles, resulting in poor overall mechanical properties. Comparative Examples 1-2 exhibited short gel times and subpar mechanical properties. While mechanical properties improved somewhat in Comparative Example 3, the gel time was significantly shortened, and elongation at break was not significantly improved. This is because the isocyanate groups in PMDI readily react with water to form carbon dioxide and urea, resulting in bubbles in the resulting polymer and reduced performance. Furthermore, the high reactivity and rapid reaction rate of isocyanate groups can lead to rapid gelation of the polyurethane resin, rendering it inoperable in the process.

[0346] In addition, the PMDI used directly in Comparative Examples 1 to 3 contains an isocyanate component (black material component) at the end as a curing agent to react with a hydroxyl-containing reaction precursor to form a carbamate to cure the polyurethane resin to obtain an initial polymer, that is, to generate a polymer containing a carbamate group. This cannot avoid the potential risk of isocyanate toxicity. Due to the high toxicity of isocyanate groups, directly handling compounds containing isocyanate end groups poses risks to human health. In particular, the manufacture of isocyanates requires phosgene, a highly toxic reaction precursor, so the production process requires very strict control, resulting in high production costs. Therefore, the production of polyurethane in Comparative Examples 1 to 3 must adopt strict process control methods and complex equipment to avoid the above problems, resulting in high costs.

[0347] In order to solve the problems existing in the above-mentioned prior art, the present invention provides a polyurethane resin which is modified to obtain a polyurethane resin with better performance and structure.

[0348] Example 1

[0349] The solidified polyurethane resin of Comparative Example 1 was used as the initial polymer for modification. The initial polymer was crushed with a crusher, 100 grams of powder was taken and poured into a round-bottom flask, and 500 grams of 1,2-propylene glycol was added and mixed; the mixture was heated under reflux for 16 hours under mechanical stirring, then cooled to room temperature, filtered, and the filtrate was distilled under reduced pressure to remove excess 1,2-propylene glycol to obtain a liquid polymer resin intermediate. The distillation fraction collected can be reused; the liquid polymer resin intermediate and 100 grams of methyl acrylate were mixed. Add enoyl chloride, 300 ml of dichloromethane and 50 g of triethylamine into a round-bottom flask, add 0.2 g of hydroquinone, stir at 0°C for 3 hours, then naturally raise the temperature to 25°C and continue stirring for 12 hours. Then filter, remove the liquid by rotary evaporation, and then redissolve in 300 ml of dichloromethane. Wash three times with 80 ml of 10% sodium carbonate aqueous solution and saturated brine respectively. Dry the organic layer with anhydrous sodium sulfate for 3 hours, filter again, and evaporate the solvent from the filtrate to obtain a liquid modified polymer.

[0350] Example 2

[0351] The solidified polyurethane resin of Comparative Example 2 was used as the initial polymer for modification. The initial polymer was crushed with a crusher, and 100 g of the powder was poured into a round-bottom flask. 500 g of ethylene glycol was then added and mixed. The mixture was heated under reflux for 16 hours with mechanical stirring, then cooled to room temperature, filtered, and the filtrate was distilled under reduced pressure to a hydroxyl value of 400 to obtain a liquid polymer resin intermediate. The distilled fraction was reused. The liquid polymer resin intermediate and 300 g of acrylic acid were added to a round-bottom flask, and 0.2 g of hydroquinone was added. The mixture was stirred at 140° C. for less than 2 hours. If the mixture was stirred for more than 2 hours, the modified polymer would crosslink. Nitrogen was continuously bubbled through the flask to blow out generated water vapor through a condenser at the upper end of the flask. The mixture was cooled to 90° C. and distilled under reduced pressure to obtain a liquid modified polymer. The distilled fraction was reused.

[0352] Example 3

[0353] The rigid foam contained in discarded Haier refrigerator housings contains polyurethane, which is used as the starting polymer material for modification. The starting polymer is crushed in a crusher, and 100 grams of the powder is poured into a round-bottom flask. 350 grams of diethylene glycol is then added. The mixture is heated under reflux for 12 hours with mechanical stirring, then cooled to room temperature, filtered, and the filtrate is distilled under reduced pressure to remove excess diethylene glycol, yielding a liquid polymer resin intermediate. The distilled fraction can be reused. The liquid polymer resin intermediate and 300 grams of methacrylic acid are added to a round-bottom flask, along with 0.2 grams of phenothiazine. The mixture is stirred at 140°C for 3 hours while bubbling nitrogen. The generated water vapor is blown out through a condenser at the top of the flask. The mixture is then cooled to 90°C and distilled under reduced pressure to yield a modified polymer. The distilled fraction can be reused.

[0354] Example 4

[0355] The rigid foam contained in discarded Haier refrigerator housings contains polyurethane, which is used as the starting polymer material for modification. The starting polymer is crushed in a crusher, and 100 grams of the powder is poured into a round-bottom flask. 350 grams of diethylene glycol is then added. The mixture is heated under reflux for 12 hours with mechanical stirring, then cooled to room temperature, filtered, and the filtrate is distilled under reduced pressure to remove excess diethylene glycol, yielding a liquid polymer resin intermediate. The distilled fraction can be reused. 100 grams of the liquid polymer resin intermediate is removed and mixed with 30 grams of NJ-204 and 300 grams of methacrylic acid in a round-bottom flask. 0.2 grams of hydroquinone is added, and the mixture is stirred at 140°C for 3 hours while bubbling nitrogen to remove generated water vapor through a condenser at the top of the flask. The mixture is then cooled to 90°C and distilled under reduced pressure to yield a modified polymer. The distilled fraction can be reused.

[0356] Example 5

[0357] The hard foam inside discarded Haier refrigerator casings and the soft foam underneath discarded Iris sofa cushions, both containing polyurethane, were crushed separately. 75 grams of the hard foam powder and 25 grams of the soft foam powder were mixed to form an initial polymer material for modification. The initial polymer was poured into a round-bottom flask, and 350 grams of 1,6-hexanediol was added. The mixture was heated under reflux for 8 hours with mechanical stirring, then cooled to room temperature and filtered. The filtrate was then distilled under reduced pressure to remove excess small-molecule alcohol, namely 1,6-hexanediol, to obtain a liquid polymer resin intermediate. The liquid polymer resin intermediate and 300 grams of methacrylic acid were added to a round-bottom flask, and 0.2 grams of hydroquinone were added. The mixture was stirred at 140°C for 3 hours while bubbling nitrogen to remove generated water vapor through a condenser at the top of the flask. The mixture was then cooled to 90°C and distilled under reduced pressure to obtain the modified polymer. The collected fraction can be reused.

[0358] Comparative Example 4

[0359] 140g of NJ-303 and 400g of methacrylic acid were added to a round-bottom flask, along with 0.2g of hydroquinone. The mixture was stirred at 140°C for 3 hours while bubbling nitrogen through it. The generated water vapor was blown out through the condenser at the top of the flask. The mixture was then cooled to 90°C and distilled under reduced pressure to obtain a liquid polyacrylate resin. The collected fractions can be reused.

[0360] The modified polymers obtained in Examples 1-5 and the polyacrylate resin of Comparative Example 4 were added with a certain amount of hydroxyethyl methacrylate, followed by the addition of 2% by weight of the modified polymer as a free radical initiator, dibenzoyl peroxide (PdL). After stirring to dissolve into a uniform solution, a portion was used to test the gel time, while the remaining portion was poured into a mold preheated to 70°C. The temperature was then raised to 120°C over 20 minutes and maintained for 30 minutes. This yielded a cured polyurethane resin plate (i.e., a semi-cured material). The mechanical properties of the pre-cured material were tested according to GB / T 2567-2008, Test Methods for Properties of Cast Resins. The test results are shown in Table 2 below:

[0361] Table 2: Resin reactivity, cured sheet quality and mechanical properties obtained in Examples 1 to 5 and Comparative Example 5

[0362] As can be seen from the test data in Table 2, the polyurethane resin obtained by the present invention poses no risk of isocyanate exposure during operation. The resin is also moisture-sensitive and free of foaming issues. Therefore, the resulting polyurethane resin sheet avoids potential quality risks associated with foaming. The gel time is significantly longer than that of conventional polyurethane resins, resulting in excellent composite material processing and operability. Furthermore, after curing, the modified polymer exhibits significantly better mechanical properties than conventional polyurethane resins. Compared to Comparative Example 4, which does not contain polyurethane, the modified polymer exhibits improved performance, particularly in terms of elongation at break, demonstrating enhanced toughness and fully utilizing the advantages of polyurethane.

[0363] The difference between Example 2 and Example 1 lies in the different components of the polyol used to prepare the initial polymer and the different degradation agents used. Example 2 uses a bifunctional, long-chain, low-hydroxyl polyol NJ-204 to replace a portion of the trifunctional, short-chain, high-hydroxyl polyol NJ-303, thereby improving the toughness of the manufactured polyurethane resin.

[0364] Furthermore, because Example 2 uses a lower molecular weight ethylene glycol with all primary terminal hydroxyl groups instead of 1,2-propylene glycol, which has half secondary terminal hydroxyl groups, as the degradation agent, and primary hydroxyl groups are far more reactive than secondary hydroxyl groups, the degradation rate is significantly accelerated, significantly shortening the reaction time. Thus, Example 2 replaces a portion of the trifunctional, short-chain, high-hydroxyl polyol NJ-303 with a difunctional, long-chain, low-hydroxyl polyol NJ-204. This modifies the molecular chain of the initial polymer from Example 1, increasing its flexibility and improving the toughness of the resulting polyurethane resin. This demonstrates that the method of the present invention can improve the performance of the resulting polyurethane resin by simply modifying the molecular properties of the initial polymer.

[0365] Example 3 differs from Examples 1 and 2 in that the initial polymer is derived from a different raw material source and a different degradation agent. The initial polymer in Example 3 was modified using common polyurethane waste instead of virgin polyurethane produced using the prior art. The results demonstrate that the polyurethane resin produced using this waste material according to the method of the present invention exhibits similar properties to the virgin polyurethane, and both exhibit superior properties to polyurethanes produced using isocyanates in the prior art, as well as to the acrylic polymer produced using degradation agents and unsaturated acids, as in Comparative Example 4, which contains no polyurethane.

[0366] Because the molecular structure and content of characteristic carbamate groups in polyurethane waste are similar to those of polyurethane made from virgin material, if it contains only ester and acrylate groups and no carbamate groups, it will lack the properties of carbamate groups, such as toughness. In Example 3, by replacing ethylene glycol with diethylene glycol, which has higher flexibility and all primary hydroxyl groups, the flexibility of the initial polymer's molecular chain is improved, thereby enhancing the toughness of the polyurethane resin.

[0367] Example 4 differs from Example 3 in that polyol NJ-204 is added for esterification with a resin intermediate, namely an unsaturated acid, resulting in a polyurethane resin with even greater toughness. Because the initial polymer is a rigid foam, the resulting resin intermediate, produced after degradation, has a short molecular chain and a high degree of branching. Therefore, the polyurethane resin produced in Example 3 still lacks toughness. However, the addition of the long-chain, bifunctional polyol NJ-204 results in the polyurethane resin produced in Example 4 containing flexible polyester molecules with unsaturated double bonds. The reaction of the unsaturated double bonds connects the soft segments of the flexible polyester molecules to the hard segments of the rigid polyurethane molecules, improving the molecular structure of the initial polymer and imparting even greater toughness to the polyurethane resin.

[0368] The difference between Example 5 and Example 3 is that polyurethane soft foam waste is used to replace a part of polyurethane rigid foam waste as the initial polymer, and long-chain 1,6-hexanediol is used instead of diethylene glycol, and a polyurethane resin with higher toughness is obtained.

[0369] Since polyurethane flexible foam waste is manufactured from isocyanates and long-chain polyols, long-chain polyols are generated in the resin intermediate after degradation, which is equivalent to introducing long-chain polyols into the resin intermediate. Based on principles similar to those described in Example 4, the toughness of the polyurethane resin can be improved. Furthermore, 1,6-hexanediol does not contain ether bonds, making it less susceptible to oxidative decomposition of the degradation agent during high-temperature degradation. This helps reduce byproducts during the degradation process and allows the degradation agent to be repeatedly reused after collection by vacuum distillation.

[0370] Example 6

[0371] The hard foam inside the discarded Haier refrigerator shell and the soft foam under the discarded Iris sofa cushion both contain polyurethane. They are crushed separately, and 75 grams of powder from the hard foam and 25 grams of powder from the soft foam are taken and mixed to form an initial polymer material for modification. The initial polymer is poured into a round-bottom flask, and 350 grams of 1,6-hexanediol is added. Under mechanical stirring, it is heated under reflux for 8 hours, then cooled to room temperature and filtered to obtain a liquid polymer resin intermediate. The hydroxyl value of the liquid polymer resin intermediate is tested, and then 0.95 moles of methacrylic acid are added according to the molar number of hydroxyl groups, and 0.075% of hydroquinone by weight of methacrylic acid is added. The mixture is stirred at 140°C for 3 hours, and nitrogen is bubbled through the mixture continuously to blow out the generated water vapor from the condenser at the top of the flask. The mixture is then cooled to 90°C and distilled under reduced pressure to obtain a modified polymer.

[0372] Example 7

[0373] The hard foam inside discarded Haier refrigerator casings and the soft foam underneath discarded Iris sofa cushions, both containing polyurethane, were crushed separately. 75 grams of the hard foam powder and 25 grams of the soft foam powder were mixed to form an initial polymer material for modification. The initial polymer was poured into a round-bottom flask, and 350 grams of 1,6-hexanediol was added. The mixture was heated under reflux for 8 hours with mechanical stirring, then cooled to room temperature and filtered to obtain a liquid polymer resin intermediate. The hydroxyl value of the liquid polymer resin intermediate was tested, and then 0.95 moles of methacrylic acid and 0.075% hydroquinone (based on the weight of the methacrylic acid) were added. The mixture was stirred at 140°C for 3 hours while bubbling nitrogen to remove generated water vapor through a condenser at the top of the flask. The mixture was then cooled to 90°C to obtain a modified polymer.

[0374] The components were mixed according to the proportions in Table 3 and stirred to form a uniform solution. A portion was used to test the gel time, while the remaining portion was poured into a mold preheated to 70°C. The temperature was then raised to 120°C over 20 minutes and maintained for 30 minutes. This yielded a cured polymer plate (i.e., prepreg). The mechanical properties (TBPB) of the plate were tested according to GB / T 2567-2008, Test Methods for Properties of Cast Resin Bodies. The test results are shown in Table 3 below:

[0375] Table 3: Resin reactivity, cured sheet quality and mechanical properties obtained in Examples 6-7

[0376] Example 6 eliminates the reduced pressure distillation step after the degradation reaction, thereby obtaining a high-viscosity polymer resin intermediate with a high carbamate content and a reactive diluent.

[0377] Example 7 eliminates the vacuum distillation steps after the degradation reaction and after the esterification reaction, simplifying the reaction and producing a low-viscosity polyurethane resin without sacrificing performance. This is because the elimination of the vacuum distillation step allows the degradation agent to participate in the esterification reaction as part of the resin intermediate. The short-chain degradation agent reacts with the unsaturated acid ester to produce a short-chain acrylate with low viscosity, which becomes a reactive diluent for the polymer resin intermediate and participates in the curing reaction, becoming part of the cured polyurethane resin. Thus, this embodiment completes the preparation of the reactive diluent and the preparation of the modified polyurethane in a single step. The modified polymers produced in Examples 6 and 7 each have independent properties and uses, expanding the product's application areas.

[0378] The present invention further provides a process for using the polyurethane resin to prepare a composite material.

[0379] Example 8

[0380] The modified polymer obtained in Example 3 was heated to 90° C. to reduce the viscosity, and then 1% dicumyl peroxide by weight of the resin was added and stirred for 20 minutes to promote the dissolution of dicumyl peroxide in the modified polymer to obtain a resin mixture (i.e., a semi-cured material).

[0381] Place a polyethylene (PE) film on a hot plate heated to 90°C, and then place a layer of 400 g / m 2Pour the hot resin mixture onto a heavy gingham cloth, then layer another layer of the same cloth on top, followed by a layer of PE film. Use a roller to roll the PE film and expel air trapped between the fiberglass crevices, ensuring the resin mixture fully saturates all four layers of gingham cloth. The impregnated fiberglass cloth, along with the two layers of PE film, is then transferred to a flat table and allowed to cool to room temperature, resulting in a prepreg. After 24 hours at room temperature, the prepreg becomes soft and malleable, making it easy to cut. After removing the PE film, it remains slightly sticky but not tacky, meeting the processing requirements for prepreg materials.

[0382] Furthermore, the prepreg material is cured, the PE film is torn off the prepreg, 3 prepregs are stacked together (a total of 6 layers of gingham cloth), and hot pressed on a press. The temperature of the lower layer of the press is 150°C, the temperature of the upper layer is 160°C, and the pressure is 3MPa maintained for 10 minutes. After cooling to less than 50°C, demoulding is carried out to obtain a cured polyurethane resin composite material plate with a thickness of 1.9mm.

[0383] Example 9

[0384] The modified polymer obtained in Example 5 was obtained, and 20% of the resin weight of ethylene glycol diacrylate, 2% of methyl ethyl ketone peroxide (MEKP) and 0.3% of blue water (cobalt isooctanoate) were added and stirred and mixed uniformly to obtain a resin mixture (i.e., a semi-cured material).

[0385] The resin mixture is brushed on a layer of 400-gram gingham cloth. After the resin fully impregnates the glass fiber cloth, another layer of glass fiber cloth is stacked on the glass fiber cloth, and then the resin mixture is brushed on it to fully impregnate the second layer of glass fiber cloth. The operation is carried out sequentially, and a total of 6 layers of glass fiber cloth are stacked to obtain a hand-laid fiber impregnation material. This hand-laid fiber impregnation material is then sandwiched between two layers of flat tempered glass plates with a release agent, with a thickness limit of 1.9 mm. It is placed for 24 hours to cure at room temperature, and then placed in a 100°C oven for curing for 1 hour, and then cooled to room temperature to obtain a cured polyurethane resin composite material plate. Among them, the release agent can be used based on the type of release agent commonly used in the prior art, and the present invention will not be repeated here.

[0386] Comparative Example 5

[0387] The polyurethane resin prepared in Comparative Example 1 was obtained, heated to 90° C. to reduce the viscosity, and then 1% dicumyl peroxide by weight of the resin was added and stirred for 20 minutes to promote the dissolution of dicumyl peroxide in the modified polymer to obtain a resin mixture.

[0388] Place a polyethylene (PE) film on a hot plate heated to 90°C, and then place a layer of 400 g / m 2The resin mixture, while still hot, was poured onto a heavy gingham cloth. A second layer of the same cloth was then placed on top, followed by a layer of PE film. A roller was used to roll the PE film over the cloth to expel air trapped between the fiberglass layers, ensuring that the resin mixture fully impregnated all four layers of gingham cloth. The impregnated fiberglass cloth, along with the two layers of PE film, was then transferred to a flat table and allowed to cool to room temperature, resulting in a prepreg. After leaving the prepreg at room temperature for 24 hours, it was found to be highly bubbly and hard to the touch, lacking formability and making it difficult to cut. This made it unsuitable for use as a prepreg, let alone for the subsequent curing step.

[0389] Comparative Example 6

[0390] The polyurethane resin prepared in Comparative Example 2 was obtained, and 20% of the resin weight of ethylene glycol diacrylate, 2% of methyl ethyl ketone peroxide (MEKP) and 0.3% of blue water (cobalt isooctanoate) were added and stirred and mixed uniformly to obtain a resin mixture.

[0391] The resin mixture was applied to a layer of 400g gingham cloth. After the resin fully impregnated the fiberglass cloth, another layer of fiberglass cloth was stacked on top, and the resin mixture was applied again to fully impregnate the second layer. This process was repeated for a total of six layers of fiberglass cloth, resulting in a hand-layup fiber impregnation. This hand-layup fiber impregnation was then sandwiched between two layers of flat tempered glass sheets with a release agent, with a maximum thickness of 1.9mm. The impregnation was allowed to cure at room temperature for 24 hours, then post-cured in a 100°C oven for 1 hour, and then cooled to room temperature to produce a cured composite material. However, after 24 hours at room temperature, it was observed that the composite material, while cured, contained numerous bubbles. Even after post-curing in a 100°C oven for 1 hour, numerous bubbles were still present. This indicates that conventional polyurethane, due to its water sensitivity, is not suitable for preparing qualified composite materials using conventional composite material processing.

[0392] Tensile tests were performed on the composite material plate samples of Example 8, Example 9 and Comparative Example 6 (test standard GB / T1447-2005). The results are listed in Table 4:

[0393] Table 4: Composite material board properties

[0394] Example 8 demonstrates a process for preparing a composite material from a high-viscosity, high-carbamate-content polyurethane resin, used for the preparation of a prepreg. This method utilizes heating to reduce the viscosity of the polyurethane resin. This method enables the use of resins with high polyurethane content, reducing the cost of the polyurethane resin during the modification process while also improving its performance. This is because a higher initial polymer waste content leads to a higher carbamate content, resulting in better performance and lower production costs.

[0395] Example 9 demonstrates a method for adapting the modified polymer obtained in Example 5 to the low-viscosity composite material process requirements, using low-viscosity ethylene glycol diacrylate as an active diluent to reduce the viscosity of the material with a high polyurethane content so that it can adapt to the requirements of various composite material processes.

[0396] The test data in Tables 1-4 above demonstrate that the polyurethane resin obtained by the present invention is moisture-sensitive and foam-free, even without strict, sealed curing conditions. Consequently, the resulting resin sheets avoid potential quality risks associated with foaming and exhibit significantly longer gel times than existing polyurethane resins, significantly improving the processing convenience of polyurethane resins in composite material processing. After curing, the modified polymer exhibits significantly superior mechanical properties to existing polyurethane resins. Furthermore, compared to Comparative Examples 4 and 6 employing prior art, the performance of the polyurethane resin and its composite material of the present invention is also improved, particularly in terms of elongation at break, demonstrating enhanced toughness and fully utilizing the advantages of polyurethane.

[0397] The present invention reduces or even avoids the direct use of the polyurethane black component MDI in the reaction to prepare the polyurethane resin material. Instead, it further processes the existing solidified polyurethane resin to modify and prepare a polyurethane resin with better performance. The polyurethane resin provided by the present invention can not only maintain the unique advantages of polyurethane itself, but also alleviate or even avoid the above-mentioned problems of the prior art. In addition, it can also optimize the original polyurethane molecular structure by introducing new reactants and cross-linking groups, so that the resin has a longer process operation time and the comprehensive mechanical properties of the cured resin can also be significantly improved. The introduced new reactants and cross-linking groups can be acids, acid anhydrides or carboxylates, which undergo esterification reaction with the hydroxyl groups of the resin intermediate to form ester bonds. Accordingly, the main chain segments of the reactants are also introduced into the molecular main chain of the initial polymer, thereby optimizing the original polyurethane molecular structure. Furthermore, through the active groups on the reactants, such as the unsaturated double bonds on the acid, acid anhydride or carboxylate compound, the generated new resin has new cross-linking groups, such as unsaturated double bonds. In this way, the modified polymer can be cross-linked through the new cross-linking groups. New cross-linking groups such as unsaturated double bonds are more controllable than isocyanate groups. They may not react at low temperatures or room temperatures, but only react at a certain temperature. Their practicality is far superior to isocyanate groups, and they will react with polyols even at extremely low temperatures. Therefore, the working performance of the modified polymer can be greatly improved.

[0398] Furthermore, the present invention utilizes much lower-cost polyurethane waste for degradation, employing an unsaturated carboxylic acid and alcoholysis product for esterification. This not only introduces new unsaturated double bonds as crosslinking groups, but also modifies the polyurethane molecular chain through the use of degradation agents and unsaturated carboxylic acids with different structures, improving its mechanical properties and processability. Furthermore, the polyurethane resin produced by this method can be further used to manufacture composite prepregs and composite materials, significantly improving existing composite materials.

[0399] It should be noted that there are other options for the steps of using alcoholysis to degrade the initial polymer to produce a resin intermediate, then introducing unsaturated double bond cross-linking groups through esterification to modify the polyurethane resin, and finally using an initiator to cure the resin to produce polyurethane, such as:

[0400] Using compounds containing both hydroxyl groups and unsaturated groups to decompose initial polymers to make new resins;

[0401] Degrading the initial polymer using other methods to create a new resin with cross-linking groups;

[0402] Other methods are used to degrade the initial polymer to produce a resin intermediate with active groups, and then new reactants are introduced through the reaction of the active groups to make a modified polymer. Finally, the modified polymer is cured by the reaction of the active groups on the new reactants to produce a cured polyurethane resin with better performance.

[0403] Part II: Derivative Example Group Alpha-Recovery Polyols

[0404] The second aspect of the present invention relates to a method for treating an alcohol mixture.

[0405] Because polyurethane is widely used in the market of household and daily necessities, end consumer produces a large amount of polyurethane material and needs to recycle after use.And in the process of chemical degradation treatment polyurethane material, often produce polyol mixture with high amine value, affect subsequent use, if wherein amino compound with high amine value and polyol with low amine value are separated, just can obtain high-value amino compound and polyol with low amine value, yet there is no ready-made technology to achieve this purpose.Therefore, the present invention provides a kind of processing method of the high amine value alcohol mixture containing amino compound phenylamino group, realizes the alcohol mixture separation process to purify out multiple components and recycle the purpose.

[0406] In order to solve the above technical problems, the second part of the present invention adopts the following technical solutions:

[0407] A method for treating an alcohol mixture, wherein the alcohol mixture contains an amino compound and a low-amine-value alcohol, wherein the amine-value of the alcohol is 0 to 200 mgKOH / g, and the alcohol mixture is titrated automatically by a potentiometric titrator using a perchloric acid and glacial acetic acid titration method and calculated after the analysis is completed. The method is characterized in that the method comprises the following steps:

[0408] Step Alpha-A: dissolving the alcohol mixture in a first organic solvent to obtain an alcohol mixture;

[0409] Step Alpha-B: reacting the alcohol mixture obtained in step Alpha-A with an organic acid to obtain a reaction mixture.

[0410] The amino compound contained in the alcohol mixture reacts with the organic acid as follows:

[0411] Among them, R-NH2 is an amino compound, HA is an organic acid, and R-NH3A is an ammonium salt product;

[0412] Step Alpha-C: The reaction mixture is added to a second organic solvent, mixed evenly, and then filtered to obtain a filter cake and a filtrate. The ammonium salt product is insoluble in the second organic solvent and is present in the filter cake, while the low amine value alcohol is soluble in the second organic solvent and is present in the filtrate.

[0413] Furthermore, the amino compound includes a polyol containing an amine group and a hydroxyl group.

[0414] Furthermore, the amino compound includes a phenylamino compound, preferably a phenylamino alcohol.

[0415] Furthermore, the amino compound includes substances containing a phenylamino group.

[0416] Furthermore, the organic acid is a linear carboxylic acid and / or a polycarboxylic acid, and the carboxyl equivalent of the organic acid is not less than the amino equivalent of the alcohol mixture.

[0417] Furthermore, the polycarboxylic acid includes dicarboxylic acid.

[0418] Furthermore, the carboxyl functionality of the organic acid is not less than 2.

[0419] Furthermore, the first organic solvent is one or more selected from methanol, ethanol or isopropanol.

[0420] Further, the alcohol mixture is recovered alcohol,

[0421] Furthermore, the recovered alcohol is a recovered alcohol product produced by degradation of polyurethane waste.

[0422] Furthermore, the second organic solvent is dichloromethane.

[0423] Furthermore, the ratio of the first organic solvent to the second organic solvent is 1:1 to 10 in parts by weight.

[0424] Furthermore, the processing method further comprises:

[0425] Step Alpha-D: The filtrate obtained in step Alpha-C is evaporated to obtain a low amine value alcohol component.

[0426] Furthermore, the processing method further comprises:

[0427] Step Alpha-E: Recovering the amino compound from the filter cake obtained in Step Alpha-C.

[0428] Furthermore, step Alpha-E includes:

[0429] Step Alpha-E1: The filter cake obtained in step Alpha-C is dissolved in water and adjusted to pH ≥ 10 with an alkaline solution. The ammonium salt product in the filter cake reacts with the alkaline substance to produce an amino compound and an organic acid salt.

[0430] Step Alpha-E2: extracting and separating the product obtained in step Alpha-E1 to obtain an amino compound;

[0431] Furthermore, in step Alpha-E1, the alkaline solution is a NaOH aqueous solution, and the reaction is as follows:

[0432] Among them, NaA is an organic acid salt.

[0433] Furthermore, in step Alpha-E2, the product obtained in step Alpha-E1 is extracted with ethyl acetate, the ethyl acetate phases are combined, and distilled under reduced pressure to obtain an amino compound with a high amine value.

[0434] Furthermore, step Alpha-E further comprises:

[0435] Step Alpha-E3: The aqueous phase after extraction in step Alpha-E2 is adjusted with an acidic solution to convert the organic acid salt into an organic acid and recover it.

[0436] In step Alpha-E3, the acidic solution is hydrochloric acid, and the reaction is as follows: NaA+HCl→HA+NaCl.

[0437] Furthermore, in step Alpha-B, the reaction temperature is 20-65°C.

[0438] The second part of the present invention further claims protection for the low amine value alcohol obtained by any one of the above schemes.

[0439] The second part of the present invention further claims protection for the amino compound obtained by any one of the above schemes.

[0440] The second part of the present invention provides a convenient method for obtaining low amine value recovery alcohol (i.e., low amine value alcohol component) while separating high amine value by-products (amino compounds). The overall process of the present invention is as follows:

[0441] In a first organic solvent, the alkalinity of the phenylamino group in the recovered alcohol is utilized to cause an amino compound with a high amine value to react with a suitable organic acid at room temperature or under heating conditions to undergo an acid-base neutralization reaction to generate an ammonium salt product. Due to the difference in solubility between the amino compound in the high amine value alcohol that is reacted to form an ammonium salt product and the low amine value alcohol in the solvent, the low amine value alcohol component can be separated.

[0442] The general formula for acid-base neutralization reaction is:

[0443] Among them, R-NH2 is an amino compound, HA is an organic acid, It is an ammonium salt product.

[0444] Since the ammonium salt product has a high polarity and is difficult to dissolve in the second organic solvent, it can be filtered out, while the low amine value alcohol will remain in the second organic solvent. Therefore, the two can be separated by filtration.

[0445] After filtration and separation, the filter cake is dissolved in water and alkali is added to adjust the pH value to alkaline, that is, the ammonium salt product in the filter cake can be reduced to an amino compound and an alkali metal organic acid salt with alkali solution, and the reaction is as follows:

[0446] Among them, NaA is an organic acid salt. The ammonium salt product reacts under alkaline conditions to recover amino compounds, which are then extracted and separated to obtain amino compounds with high amine values. Amino compounds with high amine values ​​are high-value chemical products with a wide range of uses.

[0447] The organic acid salt in the remaining aqueous phase mixture is adjusted to acidity with hydrochloric acid, that is, the alkali metal organic acid salt can react with the strong acid to generate inorganic salt and organic acid, thereby recovering the organic acid. The reaction is as follows: NaA+HCl→HA+NaCl

[0448] Then, the organic acid is recovered through extraction and other steps.

[0449] On the other hand, the second part of this invention also claims protection for the low amine value alcohol component produced by steps Alpha-C and Alpha-D. Due to the reduction in amine value, the recovered alcohol can meet specifications similar to those of native alcohol, and its product value is greatly improved.

[0450] On the other hand, the second part of the present invention also claims the amino compounds prepared in step Alpha-E, including free amines and amino-containing polyols.

[0451] The second part of the present invention has the following beneficial effects compared with the prior art:

[0452] (1) The high amine value alcohol mixture is separated and purified into high amine value amino compounds and low amine value alcohol components. The two components are more valuable when used separately. The high amine value amine alcohol can be used as a curing agent and catalyst, etc., and the low amine value alcohol component can be re-involved in the process of manufacturing polyurethane, opening up different sales markets.

[0453] (2) The recovered alcohol with low amine value can be used in large proportion to manufacture polyurethane, thereby increasing the utilization ratio of polyurethane solid waste, improving production efficiency and meeting market demand;

[0454] (3) Mild reaction conditions and low production costs;

[0455] (4) The first organic solvent, the second organic solvent, the organic acid, the ethyl acetate and other media involved can be recycled and reused, thereby reducing the cost of the process;

[0456] (5) No amide groups are generated in the reaction products, which avoids the poor compatibility of amide groups with alcohols, resulting in phase separation and precipitation, and insufficient product uniformity.

[0457] The raw materials used in this embodiment can be purchased on the market. Diphenylmethane diisocyanate (PMDI): trade name 44V20L, purchased from Covestro; polyol is NJ-303, purchased from Jurong Ningwu New Materials Company.

[0458] Test Case Alpha-1

[0459] The test method for amine value used in the second part of the present invention is: measuring amine value by potentiometric titrator.

[0460] The amine value is the amount of acid required to neutralize one gram of alkaline amine, expressed in milligrams of potassium hydroxide. Amine value is often used to indicate the functionality of polyols. This experiment uses the perchloric acid / glacial acetic acid titration method, using a potentiometric titrator for automated titration. The amine value of the sample is calculated after analysis.

[0461] 1. Prepare reagents and instruments

[0462] Sample: Hydroxyl-containing compound (i.e. modified polyurethane)

[0463] Titrant: 0.1 mol / L perchloric acid glacial acetic acid standard solution

[0464] Solvent: glacial acetic acid and acetonitrile

[0465] Instruments: Thunder magnetic potentiometric titrator (model ZDJ-4B), titration stirring table, non-aqueous electrode (filling liquid is ethanol-saturated lithium chloride), 4.100mL titration cup, electronic balance (accurate to 0.1mg), beaker, graduated cylinder, volumetric flask, etc.

[0466] 2. Determination method

[0467] Weigh approximately 0.2 g of sample and dissolve it in 20 mL of glacial acetic acid. Then add 20 mL of acetonitrile to dilute it. Stir until the sample is dissolved, then transfer it to a titration cup and place it on the titration table. Set the instrument titration method according to the following parameters and perform titration analysis with a 0.1 mol / L standard perchloric acid-acetic acid solution. Obtain the results after the analysis is completed.

[0468] Titrator instrument parameters are as follows:

[0469] End point mode: differential judgment;

[0470] End point judgment volume: 5 before; 0.3 after;

[0471] Minimum drop volume: 10uL;

[0472] Maximum drop volume: 1000uL;

[0473] End point judgment differential value: 200;

[0474] Pre-titration: No;

[0475] Stirring speed: 200;

[0476] Interval between each drop: 2000m / s;

[0477] Result calculation formula: Amine value = C*V*56.11 / m

[0478] Where: V is the volume at the titration endpoint (ml); C is the concentration of the perchloric acid / glacial acetic acid standard solution (mol / L); m is the sample amount (g); 56.11 is the molar mass of potassium hydroxide (g / mol).

[0479] Test Case Alpha-2

[0480] The method for testing the hydroxyl value used in the present invention is: ASTM E1899-2016.

[0481] Test Case Alpha-3

[0482] The infrared spectroscopy analysis methods used in the present invention all refer to: General rules for infrared spectroscopy analysis methods GB / T 6040.

[0483] Comparative Example Alpha-1

[0484] Step 1: Prepare 400 g of ethylene glycol as a degradation agent;

[0485] Step 2: First, heat the degradation agent to 190°C under nitrogen protection, add 80g of polyurethane refrigerator insulation layer polyurethane rigid foam waste powder into the degradation agent and stir for alcoholysis for 12 hours;

[0486] Step 3: While hot, the mixed solution is filtered through a rapid filter paper with a pore size of 20 μm. The filtrate is subjected to vacuum distillation to obtain 81 g of modified polyurethane CJ-3-56 as a modified resin intermediate or modified resin, i.e., the recovered alcohol solution. The filter cake is dissolved in methanol and filtered through a rapid filter paper. The filter cake is then subjected to vacuum distillation until no fraction appears. After drying, 16 g is weighed. The content of the initial polyurethane in the modified polyurethane is (80-16) / 81=79%. The tested amine value is 255 mgKOH / g; the tested hydroxyl value is 540 mgKOH / g; and the viscosity is greater than 30,000 mPa·s.

[0487] According to the general rules of infrared spectroscopy analysis method GB / T 6040, the infrared spectrum of modified polyurethane CJ-3-56 is shown in Figure 25. It can be found that at 1680 cm -1 ~1780cm -1 1706cm in the wavenumber range -1 The appearance of an infrared absorption peak with an intensity of only about 0.05 indicates that the content of carbamate bonds is already low and most of the carbamate groups are degraded into amino compounds.

[0488] Step 4: The modified polyurethane resin obtained in step 3 was mixed with PMDI in a weight ratio of 1:1. The reaction began to release heat within 5 seconds, and it was impossible to prepare a cured polyurethane of uniform quality.

[0489] Step 5: The filter cake obtained in step 3 is mixed with an equal weight of N303 to form component B, with an amine value of 130 mgKOH / g, and then mixed with the curing agent PMDI in a weight ratio of component B: curing agent = 1:0.75. The reaction begins to release heat within 30 seconds, and uniform quality cured polyurethane cannot be prepared. It can only become hazardous waste or require additional processing and re-modification before use, which increases the production process and production cost.

[0490] From comparative example Alpha-1, it can be seen that the high amine value polyol mixture CJ-3-56 is difficult to apply due to its high amine value.

[0491] Example Alpha-1

[0492] Step 1: Dissolution: Take 30 g of the recovered polyol CJ-3-56 obtained in Comparative Example Alpha-1, add it to 100 mL of methanol (the first organic solvent), and stir at room temperature (25° C.) until it is completely dissolved.

[0493] Step 2: Add an organic acid to react with the phenylamino compound. Add 12.5 g of oxalic acid (at least an amino equivalent) to the solution obtained in Step 1. Stir at room temperature for 1 hour to allow the oxalic acid and phenylamino compound to fully react, yielding a reaction mixture containing an ammonium salt product and a low-amine-value polyol component.

[0494] Step 3: Extraction and Isolation of Low-Amine-Value Polyols. The reaction mixture from Step 2 is added to an excess of dichloromethane (500 mL of dichloromethane) relative to the amount of methanol solvent used in Step 1. The dichloromethane forms the second organic solvent. After stirring for 10 minutes, filter the mixture using a quick filter paper (20 μm pore size) to obtain a filter cake containing the ammonium salt product and a filtrate containing a low-amino compound content. The filter cake contains the ammonium salt product, while the filtrate contains the low-amine-value polyol component (i.e., low-amine-value alcohol). The filtrate is rotary evaporated to dryness to obtain 15 g of a refined low-amine-value polyol component with an amine value of 54 mg KOH / g and dichloromethane, as shown in Table Alpha-1. The dichloromethane can be collected via a condenser and reused.

[0495] Step 4: Recovering the amino compound. The filter cake obtained in step 3 was thoroughly dried and dissolved in 100 mL of water. The pH was adjusted to greater than 10 with a 40% aqueous NaOH solution. The mixture was then thoroughly mixed with ethyl acetate three times the volume of the water and poured into a separatory funnel for separation and extraction (100 mL x 3). The oil phase, i.e., the ethyl acetate phase, was taken and combined, thoroughly mixed, and then distilled under reduced pressure. The ethyl acetate was recovered through a condenser to obtain 14.5 g of a high-amine-value amino compound with an amine value of 441 mgKOH / g.

[0496] Table Alpha-1: Alcohol mixture reaction conditions and test results

[0497] Example Alpha-2

[0498] The difference between this embodiment and embodiment Alpha-1 is that isopropyl alcohol is used as the first organic solvent to obtain 14 g of a low amine value polyol with an amine value of 59 mgKOH / g and 15 g of an amino compound with a high amine value.

[0499] Comparative Example Alpha-2

[0500] The difference between this comparative example and Example Alpha-1 is that p-toluenesulfonic acid with the same carboxyl equivalent is used instead of oxalic acid to participate in the reaction. As a result, it is found that the reaction product does not produce a filter cake when filtered, and the separation effect cannot be achieved.

[0501] This shows that monofunctional organic acids cannot achieve the separation effect, and organic acids with a functionality of not less than 2 are required to achieve the separation effect.

[0502] Part III: Derivative Example Group Beta-Modified Polyurethane Continuous Separation

[0503] The third aspect of the present invention relates to a resin intermediate and a method for producing the resin intermediate.

[0504] According to the "Progress in the Development of Raw Materials or Chemical Recycling of Waste Polymers" (Liu Chun, Sinopec Yangzi Petrochemical Co., Ltd. Nanjing Research Institute, Nanjing, 210048, Plastic Additives, Issue 4, 2020, Issue 142), since the chemical recycling of polymers includes raw material recycling and chemical recycling, raw material recycling is to convert waste plastics into petroleum raw materials for the production of petrochemicals or plastics. It usually does not cause the performance of the chemicals or plastics to deteriorate, and there are no restrictions on their performance. Thermal recovery of raw materials uses high temperatures to break the chemical bonds of the polymer backbone. This decomposition is called high-temperature degradation or thermal cracking when carried out in the absence of air, hydrogenation when carried out in a hydrogen atmosphere, and gasification when carried out in a controlled amount of oxygen. Depending on the different transformation routes, the quality and composition of the final product are also different. Chemical recycling converts polymers into monomers or monomer fragments through chemical reactions and repolymerizes them. The goal is to obtain a new polymer that is essentially the same as the original polymer. Existing polymer recycling has the problem of excessively high impurities in degradation products and by-products. Improvements are urgently needed to overcome the disadvantages of polymer recycling and obtain polymers that better meet production standards. Therefore, the third part of the present invention provides a resin intermediate and a method for producing the resin intermediate, which can optimize the key problems of existing polymer recycling, namely high cost and by-product pollution.

[0505] The third part of the present invention provides a resin intermediate, which contains a carbamate molecular fragment and a hydroxyl group. According to the ASTM E1899-2016 method, the hydroxyl value of the resin intermediate is 5 to 800 mg KOH / g, and the amine value of the resin intermediate is 0 to 20, 20 to 30, 30 to 40, 40 to 60, 60 to 80 or 80 to 120 mg KOH / g.

[0506] Preferably, the resin intermediate has a hydroxyl value of 10 to 800 mg KOH / g. A hydroxyl value greater than 10 provides initial activity when reacting with a grafting agent or curing agent. Otherwise, the activity is too low, resulting in a slow reaction or poor performance of the cured modified polymer. Furthermore, the amine value of the resin intermediate is 0 to 120 mg KOH / g. The higher the hydroxyl value of the resin intermediate, the greater the activity, the lower the number average molecular weight (Mn), and the higher the crosslink density of the resulting cured polyurethane. The opposite is true. When the hydroxyl value exceeds 800 mgKOH / g, the average number average molecular weight Mn is too small, which will lead to the molecular weight of the modified resin obtained by further grafting being too small, making the cured polyurethane obtained by further reaction with a curing agent too brittle, or the cured polyurethane obtained by directly reacting the resin intermediate with a curing agent is too brittle; if the hydroxyl value is lower than 5 mgKOH / g, due to the lack of active hydroxyl groups, the activity of reacting with the grafting agent or curing agent is insufficient, and it is impossible to fully react with the grafting agent or curing agent so that the molecular segment characteristics of the resin intermediate contribute to the cured polyurethane to improve or enhance its performance.

[0507] If the curing agent is a compound containing isocyanate, the higher the amine value of the resin intermediate, the faster the reaction rate of the resin intermediate with isocyanate. Modified polyol products with different amine values ​​have different reaction rates with isocyanate. If the amine value is greater than 120 mg KOH / g, the reaction with the reactant containing isocyanate will be too fast, and the process operation time requirement will become higher, and there may be a situation where there is no time for the process operation. Resin intermediates with an amine value of 200-500 mgKOH / g cannot directly react with isocyanate to produce cured polyurethane because the reaction speed is too fast to operate. They can only be added in a small proportion to polyols with low amine values. Resin intermediates with an amine value of 80-200 mgKOH / g cannot directly react with isocyanate to produce cured polyurethane, but can be added in a larger proportion to polyols with low amine values. Resin intermediates with an amine value of 40-80 mg KOH / g can directly react with isocyanate to produce cured polyurethane, but can only be used in fast-curing polyurethane production processes. Resin intermediates with an amine value of 20-40 mg KOH / g can directly react with isocyanate to produce cured polyurethane and can be used in molding-curing polyurethane production processes. Resin intermediates with an amine value of 0-20 mg KOH / g can directly react with isocyanate to produce cured polyurethane and can be used in slow-curing polyurethane production processes.

[0508] Furthermore, the resin intermediate does not contain R1-NH-CO-R2 amide groups. Compared to the degradation products produced by the method disclosed in the existing patent US11124623B2, the products contain R1-NH-CO-R2 groups because acid or anhydride is used in the degradation process. This method not only prolongs the degradation time, but also requires the addition of acid or anhydride as an amine removal agent, which increases the raw material cost. Furthermore, according to the method disclosed in US11124623B2, the reaction and combination of the acid anhydride and the degradation product increases the molecular weight of the degradation product, impairs its compatibility with the polyol, and increases its particle size, resulting in poor compatibility with the polyol.

[0509] Furthermore, according to the infrared spectrum test of GB / T6040-2019, the resin intermediate has a -1 ~1780cm - 1 There is an obvious infrared absorption peak in the wavenumber range.

[0510] Further, 1690cm -1 ~1780cm -1 The ratio of the peak intensity within the wavenumber range to the peak intensity within the range of 1480-1570 is in the range of 1.5-1.2, 1.2-1.0, 1.0-0.95, 0.95-0.67, 0.67-0.66, 0.66-0.65, and 0.65-0.60. Furthermore, the peak intensity ratio is preferably in the range of 1.5-0.6, more preferably 1.2-0.65, more preferably 1-0.66, and most preferably 0.95-0.67.

[0511] Furthermore, there is no obvious infrared absorption peak in the wavenumber range of 1090 to 1210 cm-1.

[0512] Furthermore, the number average molecular weight (Mn) of the resin intermediate measured using both RID and VWD (254 nm) detectors is distributed in the range of 150-200; 200-350; 350-700; 700-1000, 700-1000, 1000-1800, 1800-3000, 3000-5000, 5000-10000, 10000-30000, and 30000-60000 g / mol. Preferably, the area percentage of the peak corresponding to the portion of the molecular weight (Mn) exceeding 30000 measured by RID and VWD does not exceed 22%. Compared with the activated polyurethane micropowder disclosed in the existing patent, because it has only undergone less than 30 screw shearing cycles and no degradation agent is used, the degradation product has a large molecular weight and poor miscibility with the polyol. It can only be suspended in the polyol as particles, or even phase and stratify, affecting the performance of further polyurethane manufacturing. The present invention adopts a specific method to control the molecular weight distribution of most molecules of the modified polymer used as a resin intermediate to be within 30,000, preferably, within 5,000. From the test data, the area of ​​the molecular weight Mn peak below 30,000 in the RID and VWD tests is controlled to be not less than 80%, and more preferably, the area of ​​the molecular weight Mn peak below 5,000 in the RID and VWD tests is controlled to be not less than 80%.

[0513] Furthermore, the resin intermediate has a viscosity greater than 20,000 mPa·s or is solid, and is in the form of one or more of a paste, granules, flakes, powder, or strips, with the powder having a particle size of no less than 50 μm. Compared to activated polyurethane micropowders disclosed in prior patents, the modified polymer used as a resin intermediate in the present invention is easier to store, package, and transport. However, due to the hydroxyl group's high moisture absorption, excessively fine particles can absorb moisture and affect further use. Furthermore, excessively fine dust can cause environmental pollution and affect the health of operators.

[0514] Furthermore, the resin intermediate can be dissolved in a solvent and can pass through a sieve of 50 mesh to 800 mesh. The solvent includes one or more of methanol, ethanol, isopropanol, polyols, methyl ethyl ketone, acetone, cyclohexanone, DMF, DMSO, DMAC, and toluene. The temperature at which the resin intermediate is dissolved in the solvent is 40 to 150° C.

[0515] Further, the resin intermediate is prepared by the following steps:

[0516] Step A: subjecting the initial polymer to a degradation reaction with a degradation agent having an active group, thereby breaking at least a portion of the molecular chain of the initial polymer and obtaining a resin intermediate containing molecular fragments of the initial polymer and active groups;

[0517] The initial polymer includes a thermoplastic polymer having a linear or branched molecular structure or a thermosetting polymer having a cross-linked network molecular structure, and the molecular weight of the initial polymer is not less than 10,000 g / mol.

[0518] The initial polymer is polyurethane waste, the initial polyurethane is polyurethane waste,

[0519] The degradation reaction time is 0.5~2h, 2~3h, 3~6h.

[0520] Furthermore, the content of the initial polymer component in the resin intermediate is preferably not less than 50% by weight, more preferably not less than 60% by weight, and most preferably not less than 70% by weight. On the one hand, this can reduce costs, and on the other hand, it can increase the utilization rate of solid waste as much as possible, and also retain as many molecular fragments and its characteristics of the initial polymer as possible.

[0521] Further provided is a modified cured polyurethane, which is prepared by reacting any one of the above resin intermediates with a curing agent.

[0522] The solidified polyurethane can be used as the initial polyurethane to be degraded into a modified polyol product using the method of the present invention, thereby realizing the recycling of polyurethane.

[0523] In the prior art, polyurethane solid waste recycling can be categorized into physical and chemical methods. The most commonly used chemical method involves alcoholysis of polyurethane solids to release polyols, which are then blended with conventional polyols to produce new polyurethane products. However, the polyols produced by this alcoholysis method typically contain amino groups. These amino groups are generally undesirable byproducts in the industry, primarily because most of these amino groups are aromatic amines, which are toxic. Furthermore, these amines catalyze polyurethane reactions, interfering with normal polyurethane formulation adjustments and product manufacturing. Therefore, reducing the amine value of these modified polyol products from polyurethane alcoholysis has long been a challenge for the industry. A common approach is to separate and purify these polyols to minimize the amine content. However, this method adds an additional purification step, which increases the cost and reduces the yield of the polyurethane solid waste alcoholysis process. Furthermore, the purification process also generates additional waste liquids, exhaust gases, and energy consumption.

[0524] There are literature reports that use epoxy compounds to further process the alcoholysis product, and the aromatic amine is converted into a secondary amine through the ring-opening reaction of aromatic amine and epoxy. Although this method reduces the toxicity of aromatic amines, the catalytic activity problem of amines is still not solved. There are also literature reports that in the process of alcoholysis of polyurethane foam, by adding polyols, anhydrides (or acids), water or hydrogen peroxide or free radical initiators in sequence and heating for a period of time, and then adding polyurethane solids, water, anhydrides, water, alcohols, etc. in sequence, the amine value of the polyol product obtained by alcoholysis can be effectively reduced, but this method has many steps, is time-consuming, and the particle size of the obtained product is relatively large. The method of the present invention solves this problem concisely and efficiently. The present invention also provides a method for manufacturing a resin intermediate, comprising the following steps:

[0525] Step A: subjecting the initial polymer to a degradation reaction with a degradation agent having an active group, thereby breaking at least a portion of the molecular chain of the initial polymer and obtaining a resin intermediate containing molecular fragments of the initial polymer and active groups;

[0526] The initial polymer includes a thermoplastic polymer with a linear or branched molecular structure or a thermosetting polymer with a cross-linked network molecular structure, and the molecular weight of the initial polymer is not less than 10,000 g / mol.

[0527] Furthermore, the degradation reaction time is 0.5 to 2 hours, 2 to 3 hours or 3 to 6 hours.

[0528] Furthermore, step A further comprises a step of removing at least a portion of the degradation products, the removal step comprising a reduced pressure distillation step and / or an evaporation step, for removing at least a portion of the unreacted degradation agent, which can be collected, recovered and reused after removal;

[0529] Furthermore, the reduced pressure temperature of the reduced pressure distillation step is 65-95°C, 95-120°C, 120-150°C or 150-200°C; the reduced pressure distillation step is 0.01-2 mmHg, 2-5 mmHg, 5-20 mmHg, 20-100 mmHg or 100-400 mmHg.

[0530] Furthermore, the weight ratio of the initial polymer to the degradation agent is 1:0.1-0.4, 1:0.4-2, 1:2-5, 1:5-15, the initial polymer is polyurethane,

[0531] Furthermore, the degradation agent contains at least one active end group, the active end group including a hydroxyl group,

[0532] Furthermore, the degradation reaction includes an alcoholysis reaction; in the degradation reaction, the hydroxyl group of the degradation agent reacts with the chain-breaking group contained in the polyurethane, and at least a portion of the urethane bonds on the initial polymer molecular chain are opened to generate a resin intermediate having a linear or branched molecular chain structure containing a polyurethane molecular fragment and an active hydroxyl group. The degradation reaction includes the following reaction: -R1NHCOOR2-+R3(OH)n→-R1NHCOOR3(OH) (n-1) -+-R2OH

[0533] Among them, -NHCOO- is a carbamate group; R3(OH)n is a degradant, and n is greater than 1; -R1NHCOOR3(OH)(n-1)- is a molecular chain fragment containing R1 and a carbamate group and an active group hydroxyl group in the initial polyurethane molecular chain, and -R2OH is a molecular chain fragment containing R2 and at least one active group hydroxyl group in the initial polyurethane molecular chain.

[0534] Furthermore, the amine value of the resin intermediate prepared in step A is 0-20, 20-30, 30-40, 40-60, 60-80 or 80-120 mg KOH / g, the degradation agent includes a polyol, the polyol includes a diol and / or a high-functionality polyol, the diol includes a low molecular weight C2-C6 diol, the low molecular weight C2-C6 diol includes one or more combinations of ethylene glycol, propylene glycol, 1,4-butanediol, monoethylene glycol, monopropylene glycol or neopentyl glycol, and the high-functionality polyol includes glycerol, trimethylolethane, pentaerythritol, sucrose polyol, sorbitol or polyether polyol.

[0535] Furthermore, the alcoholysis reaction temperature is 110-150°C, 150-170°C, 170-180°C, 180-200°C, 200-220°C, 220-250°C; the alcoholysis reaction time is 0.5-2h, 2-3h, 3-6h, 6-12h, 12-24h, 24-48h, 48-64h. Preferably, the alcoholysis reaction temperature is 180-200°C, and the reaction time is 0.5-2h.

[0536] Furthermore, step A further includes a removal step of removing at least a portion of the degradation products, the removal step includes a filtration step, the filtration step includes: filtering the degradation products, and re-degrading the filter cake obtained by filtration as the initial polymer; the filtrate obtained by filtration contains the resin intermediate.

[0537] Furthermore, the method for manufacturing the resin intermediate includes N cyclic degradation reactions, where N is an integer greater than 1, and the N cyclic degradation reactions specifically include:

[0538] The first degradation reaction comprises: performing a first degradation reaction on the initial polymer and the degradation agent, separating a first filter cake and a first filtrate through a first filtration, and obtaining a first resin intermediate through vacuum distillation of the first filtrate;

[0539] When n is 2 to N, the nth degradation reaction is as follows: the n-1th filter cake is subjected to the nth degradation reaction with the degradation agent, the nth filter cake and the nth filtrate are separated by n filtrations, and the nth filtrate is subjected to reduced pressure distillation to obtain the nth resin intermediate.

[0540] Furthermore, the evaporation step adopts a multi-stage multi-effect evaporator, and the filtrate is cooled step by step from the heating temperature of the reaction in the degradation step in the multi-stage multi-effect evaporator while the pressure is reduced step by step. The degradation agent vapor releases heat during the step-by-step condensation process and heats the filtrate in the next stage evaporator.

[0541] Furthermore, the evaporation step uses a heat exchange part to condense and recover the degradation agent vapor, and the same degradation agent is used as a refrigerant in the heat exchange part to perform heat exchange and tail gas absorption on the degradation agent vapor.

[0542] Furthermore, the first to N resin intermediates are uniformly mixed, and the obtained mixture is reacted with a curing agent to obtain a modified polymer (ie, a modified cured polyurethane).

[0543] The raw materials used in the third part of the present invention can be purchased on the market. Diphenylmethane diisocyanate (PMDI): trade name 44V20L, purchased from Covestro; polyol is NJ-303, purchased from Jurong Ningwu New Materials Company

[0544] Test Case Beta-1

[0545] The test methods for amine value used in the third part of the present invention are all: amine value measured by potentiometric titrator.

[0546] The amine value is the amount of acid required to neutralize one gram of alkaline amine, expressed in milligrams of potassium hydroxide. Amine value is often used to indicate the functionality of polyols. This experiment uses the perchloric acid / glacial acetic acid titration method, using a potentiometric titrator for automated titration. The amine value of the sample is calculated after analysis.

[0547] 1. Prepare reagents and instruments

[0548] Sample: Hydroxyl-containing compounds (i.e., various degradation products in this patent)

[0549] Titrant: 0.1 mol / L perchloric acid glacial acetic acid standard solution

[0550] Solvent: glacial acetic acid and acetonitrile

[0551] Instruments: Thunder magnetic potentiometric titrator (model ZDJ-4B), titration stirring table, non-aqueous electrode (filling liquid is ethanol-saturated lithium chloride), 4.100mL titration cup, electronic balance (accurate to 0.1mg), beaker, graduated cylinder, volumetric flask, etc.

[0552] 2. Determination method

[0553] Weigh approximately 0.2 g of sample and dissolve it in 20 mL of glacial acetic acid. Then add 20 mL of acetonitrile to dilute it. Stir until the sample is dissolved, then transfer it to a titration cup and place it on the titration table. Set the instrument titration method according to the following parameters and perform titration analysis with a 0.1 mol / L standard perchloric acid-acetic acid solution. Obtain the results after the analysis is completed.

[0554] Titrator instrument parameters are as follows:

[0555] End point mode: differential judgment;

[0556] End point judgment volume: 5 before; 0.3 after;

[0557] Minimum drop volume: 10uL;

[0558] Maximum drop volume: 1000uL;

[0559] End point judgment differential value: 200;

[0560] Pre-titration: No;

[0561] Stirring speed: 200;

[0562] Interval between each drop: 2000m / s;

[0563] Result calculation formula: Amine value = C*V*56.11 / m

[0564] Where: V is the volume at the titration endpoint (ml); C is the concentration of the perchloric acid / glacial acetic acid standard solution (mol / L); m is the sample amount (g); 56.11 is the molar mass of potassium hydroxide (g / mol).

[0565] Test Case Beta-2

[0566] The method for testing the hydroxyl value used in the third part of the present invention is: ASTM E1899-2016.

[0567] Test Case Beta-3

[0568] The infrared spectrum analysis method used in the third part of the present invention is based on the general rules of infrared spectrum analysis method GB / T6040.

[0569] Test Case Beta-4

[0570] The third part of the molecular weight distribution test experimental method of the present invention: tetrahydrofuran is used as the solvent.

[0571] Table Beta-1: GPC analysis test parameters

[0572] Comparative Example Beta-1

[0573] Step 1: Prepare 400 g of ethylene glycol as a degradation agent;

[0574] Step 2: First, heat the degradation agent to 190°C under nitrogen protection, add 80g of polyurethane refrigerator insulation layer polyurethane rigid foam waste powder into the degradation agent and stir to react with alcoholysis for 12 hours;

[0575] Step 3: Filter the mixed solution while hot through a quick filter paper with a pore size of 20 μm. The filtrate is subjected to reduced pressure distillation to obtain 81 g of a modified polyurethane CJ-3-56 as a modified resin intermediate or as a modified resin. The filter cake is dissolved in methanol and filtered through a quick filter paper. The filter cake is then subjected to reduced pressure distillation at -1 bar and 60° C. After drying, 16 g is obtained by weighing. The content of the initial polyurethane in the modified polyurethane is (80-16) / 81=79%. The amine value of the modified polyurethane CJ-3-56 is measured to be 251 mgKOH / g; the hydroxyl value is tested to be 540 mgKOH / g, and the viscosity is greater than 30,000 mPa·s.

[0576] Step 4: Mix 80g of CJ-3-56 and 20g of NJ-303 at 120°C to obtain CJ-3-56-80 with a test amine value of 200mgKOH / g;

[0577] Step 5: Mix 60g of CJ-3-56 and 40g of NJ-303 at 120°C to obtain CJ-3-56-60 with a test amine value of 150mgKOH / g;

[0578] According to the general rules of infrared spectroscopy analysis method GB / T 6040, the infrared spectrum of modified polyurethane CJ-3-56 is shown in Figure 1. It can be found that at 1690 cm -1 ~1780cm -1 There is an obvious absorption peak in the wavenumber range, but its peak intensity is significantly lower than the peak in the range of 1480-1570, and the peak intensity is significantly lower than the peak in the range of 1090-1210 cm -1 There is no obvious single absorption peak with an intensity greater than 0.2 in the wavenumber range.

[0579] Step 6: The modified polyurethane resin CJ-3-56 obtained in step 3 was mixed with PMDI in a weight ratio of 1:1. The reaction began to release heat within 5 seconds, and it was impossible to prepare a cured polyurethane of uniform quality.

[0580] Step 7: The modified polyurethane resin CJ-3-56-80 obtained in step 4 was mixed with PMDI in a weight ratio of 1:1. The reaction began to release heat within 10 seconds, and it was impossible to prepare a cured polyurethane of uniform quality.

[0581] Step 8: Mix the modified polyurethane resin CJ-3-56-60 obtained in step 5 with PMDI in a weight ratio of 1:1. The reaction will begin to release heat within 30 seconds, and cured polyurethane can be barely produced.

[0582] Step 9: The filter cake obtained in step 3 is mixed with an equal weight of N303 to form component B, and then mixed with the curing agent PMDI in a weight ratio of B: curing agent = 1:0.75. The reaction begins to release heat within 30 seconds, and uniform quality cured polyurethane cannot be prepared. It can only become hazardous waste or require additional processing and modification before use, which increases the production process and production costs.

[0583] Comparative Example Beta-2

[0584] In this comparative example, modified polyurethane was prepared by the method disclosed in US Pat. No. 11124623B2 of H&S.

[0585] Step 1: Add 44 g of diethylene glycol, 13.5 g of maleic anhydride, and 2 g of deionized water to a four-necked flask with a condenser, evacuate the flask and replace it with nitrogen five times. Stir at 350 rpm under nitrogen protection, raise the temperature to 150°C, and stir for 90 minutes to obtain a degradation mixture.

[0586] Step 2: The degradation mixture is heated to 165° C., and 39 g of Haier refrigerator insulation layer polyurethane rigid foam powder is gradually added to the degradation mixture over 2 hours to uniformly mix the powder and the degradation mixture to obtain a reactant;

[0587] Step 3: The reactants were heated to 160° C., stirred for 16 hours, and cooled to 120° C., filtered through a 50-mesh sieve with a pore size of 270 μm. The filter cake weighed 1.2 g, yielding a degraded product, namely, a modified polyurethane, which was a dark brown fluid with a hydroxyl value of 360 mgKOH / g, an amine value of 54 mgKOH / g, and a viscosity of 12,000 mPa·s. The weight ratio of the initial polymer to the modified polymer was 39 / (44+13.5+2+39)=39.6%. According to the infrared spectroscopy analysis method general rules GB / T 6040, the results showed that at 1680 cm -1 ~1780cm -1 There is an absorption peak with high intensity in the wavenumber range of 1090~1210cm -1 There is also a single absorption peak with relatively high intensity in the wavenumber range.

[0588] Step 4: The modified polyurethane resin obtained in step 3 is mixed with PMDI in a weight ratio of 1:1. The reaction exothermic time can be extended to more than 5 minutes, and there is sufficient operation time to prepare uniform quality cured polyurethane. Therefore, it can be seen that the amine value of the modified polyurethane resin directly affects its reaction rate with the curing agent PMDI.

[0589] However, since too many reactants were added in Comparative Example 2, the reaction time was long, resulting in high costs and excessively large product particle size, which affected the promotion of the degradation technology.

[0590] Comparative Example Beta-3

[0591] Production of activated micropowder according to patent CN 113773549A

[0592] Step 1: Extruder Haier refrigerator insulation polyurethane rigid foam waste powder was placed into a twin-screw extruder (HK26MT, Nanjing Keya Chemical Equipment Co., Ltd., screw diameter 26mm, aspect ratio 68, die head with a 5.2mm diameter hole). The equipment temperatures were set to 50°C, 85°C, 85°C, and 85°C for the input, compression, shear, and extrusion sections, respectively. The screw speed was set to 80 rpm, and the number of threads was greater than 10.

[0593] The first extrusion product (brown-yellow solid) is continued to be fed into the feeding port of the screw machine to obtain the second extrusion product (brown-yellow solid), and then the second extrusion product is continued to be fed into the feeding port of the screw machine to obtain the third extrusion product (brown-yellow solid), and then the third extrusion product is continued to be fed into the feeding port of the screw machine to obtain the fourth extrusion product (brown-yellow solid). At this time, the initial polyurethane has undergone shear friction of the screw teeth more than 30 times.

[0594] The obtained products were dissolved in methanol and filtered through a 400-mesh sieve. The filtrate was vacuum distilled at -1 bar and 60°C to obtain a brown-yellow powder JS-01B with a particle size of less than 40 mesh. The tested hydroxyl value was 4 mgKOH / g and the amine value was 2.3KOH / g, indicating that although the amine value was low, the reaction activity was also low.

[0595] JS-01B was mixed evenly with an equal weight of NJ303 and placed in a colorimetric tube. It was found that the liquid film attached to the tube wall was very turbid, indicating that the solubility of the degradation product in the polyol was poor, which would affect the performance of products made from polyols containing the degradation product.

[0596] To address the technical problem of high amine values ​​in existing polyurethane solid waste degradation products, the present invention provides an optimized polyurethane modification process. Generally, at least a portion of the degraded products are removed from the reactants, and the remaining reactants continue to react to avoid excessive reaction and the increase of by-products. The process specifically comprises the following steps:

[0597] Step 1: Heat the degradation agent and polyurethane (PU) solid waste in a mixing kettle at 140-230°C for 5-180 minutes to react, and filter the degradation products. Preferably, the heating time is 10-60 minutes, more preferably 20-40 minutes. This reaction time provides high degradation efficiency and prevents excessive increases in the amine value. Furthermore, preferably, the filtration method is pressurized filtration, which provides better filtration results. Preferably, the degradation products are filtered under heating conditions to accelerate filtration and reduce cooling energy consumption.

[0598] Step 2: Multiple degradation methods can be used to filter the first degradation product, and the resulting filter cake is used as the next initial polymer for further degradation. The filtrate is evaporated and concentrated to obtain a degradation product, and the degradation agent collected by evaporation can continue to participate in the degradation reaction. Preferably, the filter cake of the first degradation product and the collected degradation agent are returned to the original reactor for degradation reaction. More preferably, the evaporation step uses a multi-stage multi-effect evaporator, and the filtrate is cooled from the heating temperature of 140-230°C in the reaction in step 1 to 60-160°C in the multi-stage multi-effect evaporator, and the pressure is reduced step by step. The degradation agent vapor releases heat during the step-by-step condensation process and heats the filtrate in the next evaporator to promote the vaporization of the degradation agent therein, and finally obtains the degradation product (modified polymer as a resin intermediate) and is packaged for storage.

[0599] Preferably, the degradation products obtained in step 2 are subjected to graded filtration to obtain products with different particle sizes.

[0600] Optionally, the fractional degradation steps in steps 1 and 2 can be performed in batches or continuously, allowing the degradation products to be separated promptly and preventing them from remaining in the mixing vessel for an extended period of time and causing side reactions, thereby improving the quality of the degradation products. For example, in one embodiment, the initial polymer is polyurethane, the degradation agent is a hydroxyl-containing compound, and the degradation reaction is an alcoholysis reaction. Prolonged alcoholysis can produce side reactions such as aniline groups, which can reduce the quality of the modified polyurethane used as a resin intermediate or modified resin. This method can simultaneously reduce the amine value and obtain a sufficient hydroxyl value to ensure sufficient reactivity of the modified polyurethane.

[0601] Step 3: The degradation agent vapor separated during the evaporation step is condensed and recovered in a heat exchange section. More preferably, the same degradation agent is used as the refrigerant in the heat exchange section for both heat exchange and tail gas absorption. The heated degradation agent and the condensed and recovered degradation agent are then fed together into a mixing kettle for reaction. This allows for the recovery of heat from condensation and tail gas absorption, saving energy.

[0602] As a specific embodiment of the present method, the present invention provides an optimized method for producing modified polyurethane, which generally comprises the following steps:

[0603] The degradation agent, ethylene glycol, is stirred and heated to 140-230°C in a reactor under nitrogen. Initial polyurethane (PU) solid waste is added and stirred and heated for 5-120 minutes to react. The first batch is then discharged and filtered while hot to obtain a filter cake. The filtrate is then concentrated in an evaporator to obtain the degradation product, modified polyurethane polyol, and to recover the degradation agent. The recovered degradation agent and filter cake are then returned to the reactor for further degradation, while new PU solid waste and degradation agent are added. This maintains the ratio of degradation agent to PU solid waste, improves degradation efficiency, and forms a continuous cycle reaction. This ensures that the degraded product remains at 140-230°C for only a short time before cooling for filtration and distillation, preventing further degradation reactions. This reduces the occurrence of side reactions and the formation of byproduct aniline compounds, allowing for the continuous production of degradation products with low amine values. Testing has shown that the amine value of the resulting degradation product is significantly lower than that of alcoholysis products produced using existing technologies. The distillation can be performed at atmospheric pressure or at reduced pressure to remove at least a portion or all of the unreacted degradation agent, which can then be collected, recovered, and reused. If the distillation is performed at reduced pressure, the reduced pressure temperature is 65-95°C, 95-120°C, 120-150°C, or 150-200°C, and the reduced pressure is 0.01-2 mmHg, 2-5 mmHg, 5-20 mmHg, 20-100 mmHg, or 100-400 mmHg.

[0604] Among them, the degradation products can be filtered in a graded manner to obtain degradation products of different particle sizes.

[0605] Preferably, the thermal degradation agent separated by vaporization in the distillation step is condensed and recovered in a heat exchange section. Preferably, more preferably, the same degradation agent is used as the refrigerant in the heat exchange section for heat exchange and tail gas absorption. The heated refrigerant degradation agent and the condensed and collected recovered degradation agent are fed together into a mixing kettle for reaction. This can recover the heat during condensation and tail gas absorption, saving energy. For example, if both the degradation agent and the refrigerant are ethylene glycol, the degradation agent is vaporized at atmospheric pressure from 194°C in a multi-effect multi-stage evaporator and cooled step by step to 140°C. The refrigerant is also heated from room temperature of 25°C to 120°C. The recovered degradation agent and a portion of the heated refrigerant are then fed together into a mixing kettle to continue the degradation reaction.

[0606] The detailed test process and results of Examples Beta-1-5 are given below for illustrative purposes:

[0607] Example Beta-1

[0608] Step 1: Prepare 400 g of ethylene glycol as a degradation agent.

[0609] Step 2.1: First Reaction Heating Degradation: Ethylene glycol was heated to 190°C, 40 g of polyurethane foam waste from the polyurethane refrigerator insulation layer was added, and an alcoholysis reaction was carried out at 190°C for 30 minutes under nitrogen protection to degrade a portion of the initial polyurethane to obtain a first reaction mixture;

[0610] Step 2.2: Filtration, stopping the reaction, and filtering the first reaction mixture while hot using rapid filter paper under reduced pressure. The filter paper has a pore size of 20 μm, obtaining 51 g of a filter cake. The filtrate is concentrated by distillation at 125° C. under reduced pressure at 0.01 mmHg to obtain 14 g of the first resin intermediate as a degradation product, i.e., the first modified polyurethane CJ-3-1. The amine value of the first modified polyurethane is measured to be 65 mgKOH / g, the hydroxyl value is 390 mgKOH / g, and the viscosity is greater than 30,000 mPa·s.

[0611] Step 3.1: Second reaction heating degradation: the degradation solution recovered in step 2.2 is heated to 190°C, the filter cake obtained in step 2.2 is re-added to the degradation solution, and the mixture is reacted at 190°C for 30 minutes under nitrogen protection to allow the filter cake to continue to degrade, thereby obtaining a second reaction mixture;

[0612] Step 3.2: Filter and stop the reaction. The second reaction mixture was filtered under reduced pressure while hot. Filtered with rapid filter paper with a pore size of 20 μm to obtain 41 g of filter cake. The filtrate was concentrated by reduced pressure distillation at 0.05 mmHg at 125°C to obtain 13 g of the second modified polyurethane CJ-3-2 (second resin intermediate). The amine value of the second modified polyurethane was 51 mgKOH / g, the hydroxyl value was 410 mgKOH / g, the viscosity was greater than 30,000 mPa·s, and it was a dark brown paste.

[0613] Step 4.1: Third reaction heating degradation: The degradation solution recovered in step 3.2 is heated to 190° C., the filter cake obtained in step 3.2 is re-added to the degradation solution, and the mixture is reacted at 190° C. under nitrogen protection for 30 minutes to allow the filter cake to continue to degrade, thereby obtaining a third reaction mixture;

[0614] Step 4.2: Stop the reaction and filter the third reaction mixture under reduced pressure while hot. Filter it with fast filter paper with a pore size of 20 μm to obtain 19 g of filter cake. The filtrate is concentrated by reduced pressure distillation at 0.5 mmHg at 125°C to obtain 21 g of a third modified polyurethane CJ-3-3 (third resin intermediate). The amine value of the third modified polyurethane is 40 mgKOH / g, the hydroxyl value is 385 mgKOH / g, the viscosity is greater than 30,000 mPa·s, and it is a dark brown paste.

[0615] Step 5.1: Fourth reaction heating degradation: The degradation solution recovered in step 4.2 is heated to 190° C., and the filter cake obtained in step 3.2 is re-added to the degradation solution. The mixture is reacted at 190° C. under nitrogen protection for 30 minutes to allow the filter cake to continue to degrade, thereby obtaining a fourth reaction mixture;

[0616] Step 5.2: Stop the reaction and filter the fourth reaction mixture under reduced pressure while hot. Filter it with fast filter paper with a pore size of 20 μm to obtain 6 g of filter cake. The filtrate is concentrated by reduced pressure distillation at 125°C under 1 mmHg to obtain 3 g of the fourth modified polyurethane CJ-3-4 (the fourth resin intermediate). The amine value of the fourth modified polyurethane is 40 mgKOH / g, the hydroxyl value is 390 mgKOH / g, the viscosity is greater than 30,000 mPa·s, and it is a dark brown paste.

[0617] Step 6.1: Fifth reaction heating degradation: The degradation solution recovered in step 5.2 is heated to 190° C., the filter cake obtained in step 5.2 is added back into the degradation solution, and the mixture is reacted at 190° C. under nitrogen protection for 30 minutes to allow the filter cake to continue to degrade, thereby obtaining a fifth reaction mixture;

[0618] Step 6.2: Stop the reaction and filter the fifth reaction mixture under reduced pressure while hot. Filter it through a 50-mesh sieve with a pore size of 270 μm to obtain 2 g of filter cake. The filtrate is concentrated by reduced pressure distillation at 125° C. and 2 mmHg at 2 mmHg to obtain 1 g of the fifth modified polyurethane CJ-3-5 (fifth resin intermediate). Testing shows that the amine value of the fifth modified polyurethane is 40 mgKOH / g, the hydroxyl value is 394 mgKOH / g, the viscosity is greater than 30,000 mPa·s, and it is a dark brown paste.

[0619] Step 7: The first modified polyurethane obtained in step 2.2, the second modified polyurethane obtained in step 3.2, the third modified polyurethane obtained in step 4.2, the fourth modified polyurethane obtained in step 5.2, and the fifth modified polyurethane obtained in step 6.2 are mixed uniformly to obtain a modified polyurethane (i.e., a modified polymer). The amine value of the modified polyurethane is measured to be 48 mgKOH / g, the hydroxyl value is 390, and the viscosity is greater than 30,000 mPa·s. The initial polyurethane content = (40-2) / (14+13+21+3+1) = 73%

[0620] Step 8: The first modified polyurethane CJ-3-1 obtained in step 2.2 is mixed as a modified resin with the curing agent PMDI in a weight ratio of 1:1, and the reaction exothermic time is extended to 100 seconds to make the preparation of the cured polyurethane operable.

[0621] Step 9: The second modified polyurethane CJ-3-2 obtained in step 3.2 is mixed as a modified resin with the curing agent PMDI in a weight ratio of 1:1, and the reaction exothermic time is extended to 2 minutes to make the preparation of the cured polyurethane operable.

[0622] Step 10: The third modified polyurethane CJ-3-3 obtained in step 4.2 is mixed as a modified resin with the curing agent PMDI in a weight ratio of 1:1, and the reaction exothermic time is extended to 4 minutes to make the preparation of the cured polyurethane more operable.

[0623] Step 11: The modified polyurethane obtained in step 7 is mixed as a modified resin with the curing agent PMDI in a weight ratio of 1:1, and the reaction exothermic time is extended to 4 minutes to make the preparation of the cured polyurethane more operable.

[0624] The infrared spectra measured for CJ-3-1 to 5 according to the general rules for infrared spectroscopy analysis methods GB / T 6040 are shown in Figures 2 to 6, and the infrared spectrum peak data are shown in Tables E2 to E6.

[0625] Table Beta-2: Infrared spectrum peak data of the first modified polyurethane CJ-3-1

[0626] Table Beta-3: Infrared spectrum peak data of the second modified polyurethane CJ-3-2

[0627] Table Beta-4: Infrared spectrum peak data of the third modified polyurethane CJ-3-3

[0628] Table Beta-5: Infrared spectrum peak data of the fourth modified polyurethane CJ-3-4

[0629] Table Beta-6: Infrared spectrum peak data of the fifth modified polyurethane CJ-3-5

[0630] From the above, it can be found that at 1690cm -1 ~1780cm -1 An obvious absorption peak with high intensity appears in the wavenumber range, and its peak intensity is significantly close to 1480-1570cm -1 The peak intensity in the range of 1090-1210 cm-1 indicates the existence of the initial polymer carbamate molecular fragments, and the concentration is high, and no large proportion of amino groups are broken down. -1 There is no obvious single absorption peak within the wavenumber range, indicating that this compound and the compound prepared by the method in Comparative Example 2 have different molecular structure characteristics due to the different reaction components. Since the positions of other infrared absorption peaks of this compound and Comparative Example 2 are similar, combined with the characteristics of other infrared absorption peaks, it can be seen that this compound does not contain the amide group produced in Comparative Example 2.

[0631] Example Beta-2

[0632] Step 1: Prepare 400 g of 1,2-propylene glycol as a degradation agent.

[0633] Step 2.1: First Reaction Heating Degradation: 1.2-propylene glycol was heated to 180°C, 40 g of polyurethane foam waste from the polyurethane refrigerator insulation layer was added, and the mixture was reacted at 180°C for 30 minutes under nitrogen protection to degrade a portion of the initial polyurethane to obtain a first reaction mixture;

[0634] Step 2.2: Filtration, stopping the reaction, and filtering the first reaction mixture while hot using rapid filter paper with a pore size of 20 μm to obtain 66 g of filter cake. The filtrate was concentrated by vacuum distillation at 125° C. and 3 mmHg at 3° C. to obtain 14 g of a degradation product as a first resin intermediate, namely, the first modified polyurethane CJ-2-1. The amine value of the first modified polyurethane was measured to be 56 mgKOH / g, the hydroxyl value was 426 mgKOH / g, the viscosity was greater than 30,000 mPa·s, and it was a brown solid.

[0635] Step 3.1: Second reaction heating degradation: the degradation solution recovered in step 2.2 is heated to 184°C, the filter cake obtained in step 2.2 is re-added to the degradation solution, and the mixture is reacted at 180°C for 30 minutes under nitrogen protection to allow the filter cake to continue to degrade, thereby obtaining a second reaction mixture;

[0636] Step 3.2: Filter and stop the reaction. Reduce the pressure and filter the second reaction mixture while hot. Filter it with fast filter paper with a pore size of 20 μm to obtain 41 g of filter cake. The filtrate is concentrated by reduced pressure distillation at 125°C to obtain 13 g of the second resin modified polyurethane CJ-2-2 (second resin intermediate). The test results show that the amine value of the second modified polyurethane is 43 mgKOH / g, the hydroxyl value is 405 mgKOH / g, the viscosity is greater than 30,000 mPa·s, and it is a brown solid.

[0637] Step 4.1: Third reaction heating degradation: The degradation solution recovered in step 3.2 is heated to 184°C, and the filter cake obtained in step 3.2 is re-added to the degradation solution. The mixture is reacted at 180°C for 30 minutes under nitrogen protection to allow the filter cake to continue to degrade, thereby obtaining a third reaction mixture;

[0638] Step 4.2: Stop the reaction and filter the third reaction mixture under reduced pressure while hot. Filter it with fast filter paper with a pore size of 20 μm to obtain 19 g of filter cake. The filtrate is concentrated by vacuum distillation to obtain 23 g of a third modified polyurethane CJ-2-3 (third resin intermediate). The amine value of the third modified polyurethane is 38 mgKOH / g, the hydroxyl value is 391 mgKOH / g, the viscosity is greater than 30,000 mPa·s, and it is a brown solid.

[0639] Step 5.1: Fourth reaction heating degradation: The degradation solution recovered in step 4.2 is heated to 184°C, and the filter cake obtained in step 3.2 is re-added to the degradation solution. The mixture is reacted at 180°C for 30 minutes under nitrogen protection to allow the filter cake to continue to degrade, thereby obtaining a fourth reaction mixture;

[0640] Step 5.2: Stop the reaction and filter the fourth reaction mixture under reduced pressure while hot using fast filter paper with a pore size of 20 μm to obtain 7 g of filter cake. The filtrate is concentrated by vacuum distillation to obtain 3 g of the fourth modified polyurethane CJ-2-4 (the fourth resin intermediate). The amine value of the fourth modified polyurethane is tested to be 40 mgKOH / g.

[0641] Step 6.1: Fifth reaction heating degradation: The degradation solution recovered in step 5.2 is heated to 180° C., the filter cake obtained in step 5.2 is added back into the degradation solution, and the mixture is reacted at 180° C. under nitrogen protection for 30 minutes to allow the filter cake to continue to degrade, thereby obtaining a fifth reaction mixture;

[0642] Step 6.2: Stop the reaction and filter the fifth reaction mixture under reduced pressure while it is hot. Filter it through fast filter paper with a pore size of 20 μm to obtain 3 g of filter cake. The filtrate is concentrated by reduced pressure distillation to obtain 1 g of the fifth modified polyurethane CJ-2-5 (fifth resin intermediate). The amine value of the fifth modified polyurethane is tested to be 38 mgKOH / g.

[0643] Step 7.1: Sixth reaction heating degradation: The degradation solution recovered in step 6.2 is heated to 180° C., the filter cake obtained in step 6.2 is added back into the degradation solution, and the mixture is reacted at 180° C. under nitrogen protection for 10 hours to allow the filter cake to continue to degrade, thereby obtaining a sixth reaction mixture;

[0644] Step 7.2: Stop the reaction and filter the sixth reaction mixture under reduced pressure while hot. Filter it through a 50-mesh sieve with a pore size of 270 μm to obtain 1.5 g of filter cake. The filtrate is concentrated by reduced pressure distillation to obtain 0.4 g of the sixth modified polyurethane CJ-2-6 (sixth resin intermediate). The amine value of the sixth modified polyurethane is tested to be 40 mgKOH / g.

[0645] Step 8: The first modified polyurethane obtained in step 2.2, the second modified polyurethane obtained in step 3.2, the third modified polyurethane obtained in step 4.2, the fourth modified polyurethane obtained in step 5.2, the fifth modified polyurethane obtained in step 6.2, and the sixth modified polyurethane obtained in step 7.2 are mixed uniformly to obtain a modified polyurethane (i.e., a modified polymer). The amine value of the modified polyurethane is measured to be 45 mgKOH / g, the hydroxyl value is 400, and the viscosity is greater than 30,000 mPa·s. The initial polyurethane content = (40-1.5) / (14+13+23+3+1+0.4) = 70.8%

[0646] Step 9: The first modified polyurethane CJ-2-1 obtained in step 2.2 is mixed as a modified resin with the curing agent PMDI in a weight ratio of 1:1, and the reaction exothermic time is extended to 100 seconds to make the preparation of the cured polyurethane operable.

[0647] Step 10: The second modified polyurethane CJ-2-2 obtained in step 3.2 is mixed as a modified resin with the curing agent PMDI in a weight ratio of 1:1, and the reaction exothermic time is extended to 2 minutes to make the preparation of the cured polyurethane operable.

[0648] Step 11: The third modified polyurethane CJ-2-3 obtained in step 4.2 is mixed as a modified resin with the curing agent PMDI in a weight ratio of 1:1, and the reaction exothermic time is extended to 4 minutes to make the preparation of the cured polyurethane more operable.

[0649] Step 12: The modified polyurethane obtained in step 8 is mixed as a modified resin with the curing agent PMDI in a weight ratio of 1:1, and the reaction exothermic time is extended to 4 minutes to make the preparation of the cured polyurethane more operable.

[0650] For modified polyurethanes CJ-2-1 to 6, the infrared spectra measured according to the general rules for infrared spectroscopy analysis methods GB / T 6040 are shown in Figures Beta-7 to 12, and the infrared spectrum peak data are shown in Tables Beta-7 to 12.

[0651] Table Beta-7: Infrared spectrum peak data of the first modified polyurethane CJ-2-1

[0652] Table Beta-8: Infrared spectrum peak data of the second modified polyurethane CJ-2-2

[0653] Table Beta-9: Infrared spectrum peak data of the third modified polyurethane CJ-2-3

[0654] Table Beta-10: Infrared spectrum peak data of the fourth modified polyurethane CJ-2-4

[0655] Table Beta-11: Infrared spectrum peak data of the fifth modified polyurethane CJ-2-5

[0656] Table Beta-12: Infrared spectrum peak data of the sixth modified polyurethane CJ-2-6

[0657] Can be found at 1690cm -1 ~1780cm -1An obvious absorption peak with high intensity appears in the wavenumber range, and its peak intensity is significantly close to 1480-1570cm -1 The peak intensity in the range of 1090-1210 cm -1 There is no obvious single absorption peak in the wavenumber range. This compound and the compound prepared by the method in the comparative example reflect different molecular structural characteristics due to the different reaction components.

[0658] The properties of CJ-3-1 to 5 in Example Beta-1, CJ-2-1 to 6 in Example Beta-2, and JS-01B in Comparative Example Beta-3 are described in Table Beta-13.

[0659] Table Beta-13: Sample Properties

[0660] In order to further illustrate the advantages of the present invention, molecular weight distribution analysis was performed on CJ-3-1 to 5 in Example Beta-1 and CJ-2-1 to 6 in Example Beta-2. The molecular weight distribution test of JS-01B, CJ-2-1 to 6 series, and CJ-3-1 to 5 series was mainly performed by GPC with reference to Test Example 4.

[0661] The RID and VWD detection diagrams of CJ-3-1 to 5 in Example Beta-1, CJ-2-1 to 6 in Example Beta-2, and JS-01B in Comparative Example 3 are shown in Figures 13 to 24, and the relative molecular weight distribution statistical tables are shown in Tables Beta-14 to 25.

[0662] Table Beta-14: CJ-3-1 relative molecular weight distribution statistics

[0663] Table Beta-15: CJ-3-2 relative molecular weight distribution statistics

[0664] Table Beta-16: CJ-3-3 relative molecular weight distribution statistics

[0665] Table Beta-17: CJ-3-4 relative molecular weight distribution statistics

[0666] Table Beta-18: CJ-3-5 relative molecular weight distribution statistics

[0667] Table Beta-19: CJ-2-1 relative molecular weight distribution statistics

[0668] Table Beta-20: CJ-2-2 relative molecular weight distribution statistics

[0669] Table Beta-21: CJ-2-3 relative molecular weight distribution statistics

[0670] Table Beta-22: CJ-2-4 relative molecular weight distribution statistics

[0671] Table Beta-23: CJ-2-5 relative molecular weight distribution statistics

[0672] Table Beta-24: CJ-2-6 relative molecular weight distribution statistics

[0673] Table Beta-25: JS-01B relative molecular weight distribution statistics:

[0674] It can be seen that the number average molecular weight Mn distribution of the degradation products of Examples Beta-1 and Beta-2 is mostly within 20,000, and the area percentage of the peak corresponding to the number average molecular weight exceeding 30,000 in the RID and VWD tests does not exceed 22% at the same time. This indicates that the particle size of the degradation products is small, which is beneficial to improving the reactivity of the next step of modification or curing to form cured polyurethane or the uniform dispersion with other compounds.

[0675] The area ratio of the number average molecular weight of JS-01B of the comparative example Beta-3 measured by RID is greater than 30%, indicating that the particles are obviously large and easily incompatible with polyols, thus affecting their performance.

[0676] Example Beta-3

[0677] The difference between this embodiment and embodiment Beta-1 is that the modified polyurethane in step 7 of embodiment Beta-1 is heated to 120° C. and then drawn into filaments with a diameter of 1 mm. The filaments are cut while hot under cold air blowing into pellets with a length of 2 mm and a diameter of 1 mm, which has the advantage of convenient packaging, storage and transportation.

[0678] Example Beta-4

[0679] The difference between this embodiment and embodiment Beta-2 is that the modified polyurethane in step 8 of embodiment Beta-2 is heated to 120° C. and then cast onto a rotating polytetrafluoroethylene roller. The sheet is formed into a 1 mm thick sheet under cold air blowing. The sheet is placed in a crusher and crushed to screen out fragments with a diameter of 1 to 5 mm and powder with a particle size greater than 40 μm. This embodiment has the advantage of convenient packaging, storage and transportation.

[0680] Example Beta-5

[0681] The difference between this embodiment and embodiment Beta-2 is that the modified polyurethane in step 8 of embodiment Beta-2 is heated to 130° C. and red pigment paste is added to change the dark brown modified polyurethane into reddish brown, which has the advantage of being aesthetically pleasing.

[0682] In Examples Beta-1 to 5, the modified polyurethanes (CJ-3-1 to 5 and CJ-2-1 to 6) as degradation products can be used as intermediate products to further react with a modified grafting agent to form a modified resin. Because of their low amine value, fewer reactants are required for the grafting reaction, reducing costs. Alternatively, the modified resin can be directly reacted with a curing agent containing an isocyanate group without causing an overly rapid reaction and loss of process operability.

[0683] Part 4: Derivatization Example Group Gamma-anhydride Reaction to Reduce Amine Value

[0684] The fourth aspect of the present invention relates to a modified polyol product and a method for producing the modified polyol product.

[0685] Due to the alcoholysis recovery of polyurethane solid materials, including polyurethane solid waste, scraps generated during the production of polyurethane products, retired polyurethane materials (refrigerator container insulation rigid foam, mattress sofa soft foam, sole materials, polyurethane elastomers, polyurethane semi-rigid foam, polyurethane adhesives, etc.) and polyurethane composite materials (window frames, beams, solar frames, sleepers, cable boxes, battery shells, brackets, etc.), some side reactions will occur during the alcoholysis recovery process, which makes the modified polyol product have a higher amine value. This is mainly because in the alcoholysis process, along with producing a large amount of aromatic amines (polyurethane materials based on aromatic isocyanates such as MDI, TDI) or aliphatic amines (polyurethane materials based on aliphatic isocyanates such as IPDI, HDI) class substances produce, this class substance has certain toxicity, the polyurethane containing this class substance and direct contact with human body can have certain infringement to human health, simultaneously, if the modified polyol product of degraded contains this class substance amount too high, namely amine value is too high, also can cause it and isocyanate reaction when making solidified polyurethane too fast, the process operation time is greatly shortened, even make process operation can't be realized, if the amine value of degraded polyol can be reduced, will both can improve the safety of modified polyurethane, can prolong the process operation time of preparing solidified polyurethane again. But how to reduce the content of these aminated substances in the modified polyol product concisely and efficiently, has been the huge challenge of polyurethane solid waste chemical degradation recovery always. Part four of the present invention provides a kind of modified polyol product and the method for manufacturing modified polyol product, can solve how to reduce the aminated substance content in the polyol product concisely and efficiently, further realize the problem of optimization of degradation process step.

[0686] First, the fourth part of the present invention provides a modified polyol product, which contains a carbamate molecular fragment and a hydroxyl group. According to the ASTM E1899-2016 method, the hydroxyl value of the modified polyol product is 5-800 mg KOH / g, and the amine value of the modified polyol product is 0-20, 20-30, 30-40, 40-50, 50-60, 60-80, 80-100, 100-120, 120-150, 150-180, 180-230, 230-280, 280-500 mg KOH / g.

[0687] Preferably, the hydroxyl value of the modified polyol product is 10 to 800 mg KOH / g, and the hydroxyl value is greater than 10. Furthermore, the amine value of the modified polyol product is 0 to 150 mg KOH / g.

[0688] The higher the hydroxyl value of the modified polyol product, the greater its activity, the smaller its average number-average molecular weight (Mn), and the higher the crosslinking density of the resulting cured polyurethane. The opposite is true. When the hydroxyl value exceeds 800 mgKOH / g, the average number-average molecular weight (Mn) is too low, which can result in the molecular weight of the modified resin obtained by further grafting being too low, making the cured polyurethane obtained by further reaction with a curing agent too brittle. Alternatively, the cured polyurethane obtained by directly reacting the modified polyol product with a curing agent is too brittle. If the hydroxyl value is less than 5 mgKOH / g, the modified polyol product has too few active hydroxyl groups and insufficient reaction activity with the grafting agent or curing agent. Consequently, the modified polyol cannot fully react with the grafting agent or curing agent, allowing the molecular segment characteristics of the modified polyol to contribute to the cured polyurethane, thereby improving or enhancing its performance.

[0689] If the curing agent is a compound containing isocyanate, the higher the amine value of the polyol product, the faster the reaction rate of the polyol and isocyanate. Modified polyol products with different amine values ​​have different reaction rates with isocyanate. If the amine value is greater than 150 mg KOH / g, the reaction with the reactant containing isocyanate will be too fast, the process operation time requirement will become higher, and there may be a situation where there is not enough time for the process operation. Modified polyols with an amine value of 180-500 mgKOH / g cannot directly react with isocyanate to produce cured polyurethane because the reaction speed is too fast to operate. They can only be added in small proportions to polyols with low amine values. Modified polyols with an amine value of 80-180 mgKOH / g cannot directly react with isocyanate to produce cured polyurethane, but can be added in larger proportions to polyols with low amine values. Modified polyols with an amine value of 40-80 mgKOH / g can directly react with isocyanate to produce cured polyurethane, but can only be used in fast-curing polyurethane production processes. Modified polyols with an amine value of 20-40 mgKOH / g can directly react with isocyanate to produce cured polyurethane, and can be used in molding-curing polyurethane production processes. Modified polyols with an amine value of 0-20 mgKOH / g can directly react with isocyanate to produce cured polyurethane, and can be used in slow-curing polyurethane production processes.

[0690] Furthermore, the modified polyol product contains an R1-NH-CO-R2 amide group. This amide group forms a highly polar bond, which is beneficial for improving the mechanical properties of the cured polyurethane prepared by reacting the modified polyol product with a curing agent.

[0691] Furthermore, according to the infrared spectrum test of GB / T 6040-2019, the absolute threshold of the infrared spectrum test is 0.001, the sensitivity is 50, and the difference between the absorbance intensity of the top and bottom of the measured infrared absorption peak is not less than 0.03. The modified polyol product measured according to the test standard is -1~1780cm -1 、1480cm -1 ~1570cm -1 and 1100cm -1 ~1210cm -1 There is an infrared absorption peak in the wavenumber range, and 1680cm - 1 ~1780cm -1 The peak height of the infrared absorption peak within the wavenumber range is not less than 1480cm -1 ~1570cm -1 The infrared absorption peak is 70% of the peak height of the infrared absorption peak in the wave number range, and there is also an infrared absorption peak in the wave number range of 1090 to 1210 cm-1, more preferably, there is an infrared absorption peak in the wave number range of 1110 to 1200 cm-1, and most preferably, there is an infrared absorption peak at 1100 cm-1. -1 ~1210cm -1 There is an infrared absorption peak in the wavenumber range. This feature, combined with other infrared spectral features, can indicate that the modified polyol product contains R1-NH-CO-R2 groups. In the present invention, preferably, 1680cm -1 ~1780cm -1 The characteristic peak absorption intensity in the range of 1480 cm -1 ~1570cm -1 The characteristic peak absorbance intensity ratio (ie, height ratio) within the range is in the range of 0.7 / 1-2.5 / 1. This feature can indicate that the proportion of phenylamino groups generated by degradation of carbamate functional groups in the modified polyol product is relatively small, and has a low amine value feature.

[0692] Furthermore, the number average molecular weight Mn peak distribution regions of the modified polyol product measured by RID and VWD (254 nm) detectors include 150-200; 200-350; 350-700; 700-1000, 700-1000, 1000-1800, 1800-3000, 3000-5000, 5000-10000, 10000-30000, and 30000-60000 g / mol. Preferably, the area ratio of Mn greater than 30000 g / mol measured by the method is not greater than 20%. The modified polyol product thus obtained has a smaller molecular weight, greater reactivity, and is distributed in various molecular weight regions, thereby achieving better compatibility when mixed with other polyols.

[0693] Furthermore, the modified polyol product has a viscosity (at 25°C, all viscosities hereafter refer to viscosities at 25°C) greater than 20,000 mPa·s or is solid. The modified polyol product is in one or more of the following forms: paste, granules, flakes, powder, or strips, with the powder having a particle size of no less than 50 μm. Compared to the activated polyurethane micropowder disclosed in CN 113773549A, which has a particle size of less than 40 μm, the modified polyol product is easier to store, package, and transport. Because hydroxyl groups are highly hygroscopic, particles that are too fine can absorb moisture and affect further use. Furthermore, excessively fine dust can cause environmental pollution and affect the health of operators.

[0694] Furthermore, the modified polyol product can be dissolved in a solvent and pass through a 50-800 mesh sieve. The solvent includes one or more of methanol, ethanol, isopropanol, polyols, methyl ethyl ketone, acetone, cyclohexanone, DMF, DMSO, DMAC, and toluene. The temperature at which the modified polyol product dissolves in the solvent is 40-150°C. This step can produce a modified polyol product solution having a particle size of 40-270 μm. Within this particle size range, the modified polyol product has good compatibility with the solvent.

[0695] Preferably, the modified polyol product is dissolved in the polyol and filtered through sieves of different mesh sizes to obtain a graded polyol composition. The solution of the modified polyol product with a small particle size and the polyol is clarified to become a refined modified polyol composition. The solution of the modified polyol product with a large particle size and the polyol is a suspension with slightly inferior performance, but can still be used in specific applications.

[0696] The polyols described in the fourth part of the present invention are all hydroxyl-containing compounds with a hydroxyl functionality greater than 1.

[0697] Further, the modified polyol product is prepared by the following steps:

[0698] Step A: subjecting the initial polymer to a degradation reaction with a degradation agent having an active group, thereby breaking at least a portion of the molecular chain of the initial polymer and obtaining a modified polyol product containing molecular fragments of the initial polymer and active groups;

[0699] The initial polymer includes a thermoplastic polymer having a linear or branched molecular structure or a thermosetting polymer having a cross-linked network molecular structure, and the molecular weight of the initial polymer is not less than 10,000 g / mol;

[0700] The initial polyurethane is polyurethane waste,

[0701] The degradation agent includes a combination of one or more of polyols, acid anhydrides, compounds containing carboxyl groups, and compounds containing both carboxyl groups and hydroxyl groups. The carboxyl group-containing compound described in the present invention can be a single compound or a reaction product of an acid anhydride and a compound containing a hydroxyl group or an amino group, and can be a synthetic product or a natural product. When the degradation agent includes polyols and acid anhydrides, the polyols and acid anhydrides react completely or partially to form a composite degradation agent containing at least one of polyols, acid anhydrides, compounds containing carboxyl groups, and compounds containing both carboxyl groups and hydroxyl groups, or a combination of more than one of the following:

[0702] The degradation reaction time is 4 to 30 minutes, 0.5 to 2 hours, 2 to 3 hours, 3 to 6 hours, 6 to 12 hours or 12 to 24 hours.

[0703] The modified polyol product of the present invention is a resin intermediate. The modified polyol product as a resin intermediate in the present invention can be subjected to a grafting reaction to generate a modified resin and then reacted with a curing agent to form a cured polyurethane, or can be directly reacted with a curing agent to form a cured polyurethane.

[0704] The degradation reaction time is related to the degradation reaction temperature, degradation mixing process, and the selection of degradation agent and catalyst. Under the premise of ensuring the quality and yield of the modified polyol product, the shorter the degradation reaction time, the lower the energy consumption and the lower the cost.

[0705] Furthermore, the degradation reaction does not include the step of adding water, hydrogen peroxide, or a free radical initiator. In the present invention, the step of not adding water means that no additional free water is added to the reaction, and no moisture is added to the normally dry polyurethane solid waste and chemical raw materials. Typically, polyurethane solid waste and chemical raw materials are used with a moisture content of less than 10 wt %, preferably less than 5 wt %, and more preferably less than 2 wt %. Optionally, the polyurethane waste is dried to reduce its moisture content.

[0706] In the prior art, it is often necessary to add water, hydrogen peroxide, or a free radical initiator to the mixture of polyol and acid anhydride to accelerate the degradation efficiency of the mixture on polyurethane waste. Even then, the degradation time can be as long as 13 hours or more. The present inventors surprisingly discovered that, using the above method, even without the addition of water, hydrogen peroxide, or a free radical initiator, a modified polyol product with a low amine value can still be obtained, and the time required can be shortened. This not only reduces raw material costs but also improves production safety and efficiency.

[0707] Furthermore, the acid anhydride or the compound containing a carboxyl group preferably contains a double bond, and the acid anhydride preferably includes maleic anhydride. This allows the modified polyol molecule to contain a double bond, which can be initiated by free radicals to increase the crosslinking density and improve mechanical properties.

[0708] Furthermore, the modified polyol product contains at least 25% by weight of the initial polyurethane component, preferably at least 40% by weight, preferably at least 50% by weight, preferably at least 60% by weight, and more preferably at least 70% by weight. This reduces costs while maximizing solid waste utilization and preserving as many of the molecular fragments and properties of the initial polymer as possible.

[0709] Furthermore, the present invention provides a modified cured polyurethane, which is prepared by reacting the modified polyol product of any one of the above schemes with a curing agent.

[0710] Furthermore, in step A, the degradation agent carries both an active group and a chain-extending group. Since the degradation agent carries both an active group and a chain-extending group, any of the above-mentioned modified polyol products carries a chain-extending group. Therefore, it can be used as a resin intermediate to react with a grafting agent to generate a cured polyurethane, and can also be directly used as a modified resin to react with a curing agent through its chain-extending group to produce a cured polyurethane.

[0711] Furthermore, the chain extending group includes a hydroxyl group.

[0712] Furthermore, the curing agent contains a reactive functional group capable of reacting with the chain extender group, and the reactive functional group includes one or a combination of an isocyanate group, an acid anhydride group, a carboxyl group, an epoxy group, an amine group, an amide group, or an aldehyde group. Preferably, the curing agent contains an isocyanate group, so that the modified polyol product can react with the curing agent to form a cured polyurethane, which can then be used as the initial polyurethane to be degraded into the modified polyol product using the method of the present invention, thereby achieving the recycling of the polyurethane.

[0713] In the prior art, polyurethane solid waste recycling can be categorized into physical and chemical methods. The most commonly used chemical method involves alcoholysis of polyurethane solids to release polyols, which are then blended with conventional polyols to produce new polyurethane products. However, the polyols produced by this alcoholysis method typically contain amino groups. These amino groups are generally undesirable byproducts in the industry, primarily because most of these amino groups are aromatic amines, which are toxic. Furthermore, these amines catalyze polyurethane reactions, interfering with normal polyurethane formulation adjustments and product manufacturing. Therefore, reducing the amine value of these modified polyol products from polyurethane alcoholysis has long been a challenge for the industry. A common approach is to separate and purify these polyols to minimize the amine content. However, this method adds an additional purification step, which increases the cost and reduces the yield of the polyurethane solid waste alcoholysis process. Furthermore, the purification process also generates additional waste liquids, exhaust gases, and energy consumption.

[0714] There are literature reports that use epoxy compounds to further process the alcoholysis product, converting the aromatic amine into a secondary amine through an aromatic amine and epoxy ring-opening reaction. Although this method reduces the toxicity of aromatic amines, the catalytic activity problem of amines remains unsolved. There are also literature reports that in the process of alcoholysis of polyurethane foam, by sequentially adding polyols, anhydrides (or acids), water or hydrogen peroxide or free radical initiators and heating for a period of time, and then sequentially adding polyurethane solids, water, anhydrides, water, alcohols, etc., the amine value of the polyol product obtained by alcoholysis can be effectively reduced. However, this method has many steps, is time-consuming, and the resulting product particle size is relatively large. The method of the present invention solves this problem concisely and efficiently.

[0715] The fourth aspect of the present invention also provides a method for producing a modified polyol product, comprising the following steps:

[0716] Step A: subjecting the initial polymer to a degradation reaction with a degradation agent having an active group, thereby breaking at least a portion of the molecular chain of the initial polymer to obtain a modified polyol product containing molecular fragments of the initial polymer and a modified polyol product having an active group;

[0717] The initial polymer includes a thermoplastic polymer having a linear or branched molecular structure or a thermosetting polymer having a cross-linked network molecular structure, and the molecular weight of the initial polymer is not less than 10,000 g / mol;

[0718] The initial polyurethane is polyurethane waste,

[0719] The degradation agent includes one or more combinations of polyols, acid anhydrides, compounds containing carboxyl groups, compounds containing hydroxyl groups, and compounds containing both carboxyl groups and hydroxyl groups.

[0720] The degradation reaction does not involve the addition of water, hydrogen peroxide or free radical initiators;

[0721] The degradation reaction time is 4 to 30 minutes, 0.5 to 2 hours, 2 to 3 hours, 3 to 6 hours, 6 to 12 hours or 12 to 24 hours;

[0722] The temperature of the degradation reaction is 110-150°C, 150-170°C, 170-180°C, 180-200°C, 200-220°C or 220-250°C.

[0723] Furthermore, the degradation agent is prepared by reacting a polyol and an acid anhydride, including a mixture of the polyol and the acid anhydride as an unreacted or partially reacted mixture or a product of a complete reaction of the polyol and the acid anhydride.

[0724] Furthermore, the polyol is a diol. The diol reacts with an acid anhydride to form a monocarboxyl and monohydroxy compound, which not only reduces the risk of crosslinking with degradation products, but also allows the carboxyl group to react with the amine group to block the amine group and reduce the amine value. At the same time, the degradation product is connected to the hydroxyl chain extension group and can react with the curing agent for curing.

[0725] Furthermore, the degradation reaction does not contain the step of adding water, hydrogen peroxide or free radical initiator.

[0726] Furthermore, the acid anhydride or the compound containing a carboxyl group preferably contains a double bond, and the acid anhydride preferably includes maleic anhydride.

[0727] Furthermore, step A includes step Gamma-A1, step Gamma-B1 and step Gamma-C1.

[0728] Step Gamma-A1: mixing an acid anhydride and a polyol to react to obtain a degradation agent, wherein the mixed reaction does not contain additional water;

[0729] Step Gamma-B1: adding polyurethane to the degradation agent obtained in step Gamma-A1, heating and mixing to allow the polyurethane to undergo a degradation reaction to obtain a reaction mixture, wherein the reaction mixture contains a modified polyol product, and the degradation reaction does not include the step of adding water, hydrogen peroxide, or a free radical initiator.

[0730] Step Gamma-C1: Filtering the reaction mixture obtained in step Gamma-B1 to obtain a filtrate and a filter cake containing a modified polyol product, wherein the filter cake can be used as a crude modified polyol product with active groups;

[0731] Optionally, the filtrate is distilled to obtain a modified polyol product, or is directly used as a modified polyol product.

[0732] Furthermore, in step Gamma-A1, the temperature of the mixing reaction is 30°C to 140°C; the mixing reaction time is 30 to 480 minutes; a temperature below 30°C results in an inefficient reduction in the amine value, and a temperature above 140°C causes a side reaction of the acid anhydride and reduces the efficiency of the acid anhydride in removing amines.

[0733] In step Gamma-B1, the degradation reaction temperature is 110 to 250° C.; the degradation reaction time is 30 minutes to 24 hours. A degradation temperature below 110° C. will result in an excessively long degradation time, while a temperature above 250° C. will cause a large number of side reactions, reduce the molecular weight of the modified polyol product, and cause the performance of the cured polyurethane to deteriorate and the process operability to deteriorate.

[0734] In step Gamma-C1, the reaction mixture is cooled to 100-180° C. If the temperature is too low, the viscosity of the reaction mixture increases and it is difficult to filter. If the temperature is too high, new side reactions will occur and new by-products will be generated.

[0735] Furthermore, the modified polyol product contains amide groups.

[0736] As another embodiment of the method disclosed in the fourth part of the present invention, polyurethane and polyol are first subjected to degradation reaction, and then anhydride or carboxylic acid is added to remove the amine value. Specifically, step A includes:

[0737] Step Gamma-A2: adding the polyurethane to the degradation agent, heating and stirring to allow the polyurethane to undergo the degradation reaction to obtain a reaction mixture, wherein the degradation reaction does not include the step of additionally adding water, hydrogen peroxide, or a free radical initiator;

[0738] Step Gamma-B2: mixing the acid anhydride and / or carboxyl-containing compound with the reaction mixture obtained in step Gamma-A2 for reaction, wherein the mixing reaction does not include the step of additionally adding water, hydrogen peroxide or free radical initiator.

[0739] Step Gamma-C2: Cooling the reaction mixture obtained in step Gamma-B2, and filtering to obtain a filtrate and a filter cake containing the modified polyol product, wherein the filter cake can be used as a crude modified polyol product with active groups;

[0740] Optionally, the filtrate is distilled to obtain a modified polyol product, or is directly used as a modified polyol product;

[0741] In step Gamma-A2, the temperature of the degradation reaction is 110 to 250° C.; the time of the degradation reaction is 30 minutes to 24 hours;

[0742] In the step Gamma-B2, the temperature of the degradation reaction is 30° C. to 180° C., and the time of the mixing reaction is 30 to 480 minutes.

[0743] As a preferred embodiment, the weight ratio of the acid anhydride to the alcoholysis agent is 0 to 1 / 100, 1 / 100 to 1 / 75, 1 / 75 to 1 / 50, 1 / 50 to 1 / 35, 1 / 35 to 1 / 25 or 1 / 25 to 1 / 20.

[0744] The fourth part of the present invention also provides an application of a modified polyol product obtained by the method of any one of the above technical solutions in the preparation of polyurethane rigid foam, which can improve its compressive strength.

[0745] The fourth part of the present invention also provides an application of a modified polyol product obtained according to any one of the methods in the above technical solutions in the preparation of polyurethane soft foam, which can improve its tear strength.

[0746] The fourth part of the present invention also provides an application of a modified polyol product obtained by the method according to any one of the above technical solutions in the preparation of a polyurethane elastomer, which can improve its tensile strength.

[0747] The fourth aspect of the present invention provides a method for treating an initial polymer, further obtaining a polyol product with a low amine value through a simple and efficient polyurethane degradation method, particularly by optimizing the alcoholysis method. In the polyurethane alcoholysis process, the present invention employs a method of adding a certain amount of anhydride or a corresponding acid to an alcohol reagent before carrying out a degradation reaction with polyurethane waste, efficiently obtaining an alcoholysis polyol product with a low amine value. The anhydride can be an anhydride of a monocarboxylic acid, such as acetic anhydride, hexanoic anhydride, or benzoic anhydride; or a cyclic anhydride, which can be selected from a wide range of monofunctional anhydrides, difunctional anhydrides, or free acid anhydrides, or mixtures thereof, such as succinic anhydride, methylhexahydrophthalic anhydride, chlorendic anhydride, pyromellitic anhydride, and trimellitic anhydride.

[0748] Furthermore, the modified polyol product prepared by the alcoholysis reaction can be reused in the preparation of new polyurethane products with common polyols (i.e., polyols obtained by conventional industrial ring opening of ethylene oxide, propane, or butane, or polyester polyols, etc.) at a mass ratio of 5 / 95 to 55 / 45. The modified polyol product has similar performance to the original PU product (i.e., obtained by common polyol without adding any recycled products), thus realizing a closed loop from the production of polyurethane products to recycling and re-making into new products, improving the production efficiency and economic value of the industry, and having broad market application prospects.

[0749] In addition, the inventors unexpectedly discovered that if the degradation reaction does not involve water, hydrogen peroxide, and free radical initiators, and only anhydrides or acids are added during the alcoholysis process, the amine value of the polyol product can be further reduced, and the particle size of the polyol product will also be smaller, making it more suitable as a polyol raw material for the preparation of new polyurethane materials.

[0750] The raw materials used in the specific embodiments of the fourth part of the present invention are commercially available: diphenylmethane diisocyanate (PMDI): trade name 44V20L, purchased from Covestro; polyols NJ-303 and NJ-204, purchased from Jurong Ningwu New Materials Company.

[0751] Test Case Gamma-1

[0752] The hydroxyl value test methods used in this section are all ASTM E1899-2016.

[0753] Test Case Gamma-2

[0754] The test methods for amine values ​​used in this section are: amine values ​​measured by potentiometric titrator.

[0755] The amine value is the amount of acid required to neutralize one gram of alkaline amine, expressed in milligrams of potassium hydroxide. Amine value is often used to indicate the functionality of polyols. This experiment uses the perchloric acid / glacial acetic acid titration method, using a potentiometric titrator for automated titration. The amine value of the sample is calculated after analysis.

[0756] 1. Prepare reagents and instruments

[0757] Sample: Hydroxyl-containing compound (i.e. modified polyol product)

[0758] Titrant: 0.1 mol / L perchloric acid glacial acetic acid standard solution

[0759] Solvent: glacial acetic acid and acetonitrile

[0760] Instruments: Thunder magnetic potentiometric titrator (model ZDJ-4B), titration stirring table, non-aqueous electrode (filling liquid is ethanol-saturated lithium chloride), 4.100mL titration cup, electronic balance (accurate to 0.1mg), beaker, graduated cylinder, volumetric flask, etc.

[0761] 2. Determination method

[0762] Weigh approximately 0.2 g of sample and dissolve it in 20 mL of glacial acetic acid. Then add 20 mL of acetonitrile to dilute it. Stir until the sample is dissolved, then transfer it to a titration cup and place it on the titration table. Set the instrument titration method according to the following parameters and perform titration analysis with a 0.1 mol / L standard perchloric acid-acetic acid solution. Obtain the results after the analysis is completed.

[0763] Titrator instrument parameters are as follows:

[0764] End point mode: differential judgment;

[0765] End point judgment volume: 5 before; 0.3 after;

[0766] Minimum drop volume: 10uL;

[0767] Maximum drop volume: 1000uL;

[0768] End point judgment differential value: 200;

[0769] Pre-titration: No;

[0770] Stirring speed: 200;

[0771] Interval between each drop: 2000m / s;

[0772] Result calculation formula: Amine value = C × V × 56.11 / m

[0773] Where: V is the volume at the titration endpoint (ml); C is the concentration of the perchloric acid / glacial acetic acid standard solution (mol / L); m is the sample amount (g); 56.11 is the molar mass of potassium hydroxide (g / mol).

[0774] Test Case Gamma-3

[0775] The method for testing the hydroxyl value used in the present invention is: ASTM E1899-2016.

[0776] Example Gamma-1

[0777] Under nitrogen protection, 80 grams of maleic anhydride and 800 grams of ethylene glycol are mixed, heated to 50°C and stirred for 1 hour to dissolve them evenly to obtain a degradation agent; then 200 grams of polyurethane waste (recycled refrigerator rigid foam waste) is added to the degradation agent, heated and stirred for 12 hours until the polyurethane solid is dissolved, wherein the heating temperature is maintained at 184°C to obtain a reaction mixture; then the reaction mixture is cooled to 120°C, filtered through a filter (pore size 60um) and cooled to room temperature to obtain a filtrate containing a modified polyol product and a filter cake, the obtained filter cake is dissolved in 10 times methanol and filtered with a slow filter paper with a pore size of 13um, and the remaining solid on the filter paper is dried and weighed to 20g. The resulting filtrate was subjected to reduced pressure distillation to remove excess ethylene glycol to obtain 330 g of a modified polyol product numbered JJ / CJ-3 / SJZH-2, having a viscosity greater than 30,000 mPa·s and a brown paste at room temperature. The initial polyurethane content in the modified polyol product was (200-20) / 330=54.5 wt%. The obtained product contained amide groups. The amine value of the modified polyol product was tested to be 16 mgKOH / g, and the hydroxyl value was 360 mgKOH / g. The modified polyol product can be used to manufacture polyurethane rigid foam.

[0778] The modified polyol product prepared in this example was mixed with PMDI in a weight ratio of 1:1 to prepare a cured polyurethane with uniform quality.

[0779] The infrared spectrum of the modified polyol product JJ / CJ-3 / SJZH-2 was measured according to the general rules for infrared spectroscopy analysis GB / T 6040, as shown in Figure 26. The infrared spectrum peak data are shown in Table Gamma-1. It can be found that at 1680 cm - 1 ~1780cm -1 1713.25cm in the wave number range -1 There is an obvious absorption peak at 1090~1210cm -1 1172.18cm in the wave number range -1There is an obvious single absorption peak at 1610 cm -1 and 1480cm -1 ~1570cm -1 1510 cm in the wavenumber range -1 There is also an obvious absorption peak nearby.

[0780] Table Gamma-1: Infrared spectrum peak data of modified polyol products JJ / CJ-3 / SJZH-2

[0781] According to Table Gamma-1, the height ratio of the 1713.25 peak to the 1513.07 peak is 1.67 / 1.

[0782] Example Gamma-2

[0783] Under nitrogen protection, 80 grams of succinic anhydride and 600 grams of propylene glycol are mixed, then heated to 95°C and stirred for 1 hour to dissolve them evenly to obtain a degradation agent; then 200 grams of polyurethane waste (recycled container rigid foam waste) is added to the degradation agent, heated and stirred for 10 hours until the polyurethane solid is dissolved, wherein the temperature is maintained at 180°C to obtain a reaction mixture; then the reaction mixture is cooled to 120°C, filtered through a filter (75um) and cooled to room temperature to obtain a filtrate containing a modified polyol product and a filter cake. The filter cake was dissolved in 10 times the amount of methanol and filtered through a slow filter paper with a pore size of 13 μm. The remaining solid on the filter paper was dried and weighed to 18 g. The filter cake had an amine value of 14 mgKOH / g and a hydroxyl value of 140 mgKOH / g, which can be used as an active filler for polyols. The filtrate was decompressed and distilled to remove excess propylene glycol to obtain 360 g of a modified polyol product numbered CJ35 / H12, with a viscosity greater than 30,000 mPa.s and a brown paste at room temperature. The initial polyurethane content in the modified polyol product was (200-18) / 360 = 50.5 wt%. The product contained amide groups. The amine value of the modified polyol product was tested to be 23 mgKOH / g and the hydroxyl value was 380 mgKOH / g, as determined according to DIN 53176. The modified polyol product prepared in this example was mixed with PMDI in a weight ratio of 1:1 to prepare a cured polyurethane of uniform quality.

[0784] The modified polyol product can be used to prepare polyurethane rigid foam.

[0785] The infrared spectrum of the CJ35 / H12 modified polyol product was measured according to the general rules for infrared spectroscopy analysis methods GB / T 6040, as shown in Figure 27. The infrared spectrum peak data are shown in Table Gamma-2. It can be found that at 1680 cm -1 ~1780cm -1 1719.34cm in the wave number range-1 There is an obvious absorption peak at 1090~1210cm -1 1184.74cm in the wave number range -1 There is an obvious single absorption peak at 1610 cm -1 and 1480cm -1 ~1570cm -1 1510 cm in the wavenumber range -1 There is also an obvious absorption peak nearby.

[0786] Table Gamma-2: Infrared spectrum peak data of modified polyol product CJ35 / H12

[0787] According to Table Gamma-2, the height ratio of the 1719.34 peak to the 1510.43 peak is 0.73 / 1.

[0788] Example Gamma-3

[0789] Under nitrogen protection, 80 grams of phthalic anhydride and 300 grams of diethylene glycol were mixed, then heated to 80°C and stirred for 1 hour to dissolve them evenly to obtain a degradation agent; then 600 grams of polyurethane waste (recycled polyurethane soft foam waste) was added to the degradation agent, heated and stirred for 16 hours until the polyurethane solid dissolved, wherein the temperature was maintained in the range of 200°C to obtain a reaction mixture; then the reaction mixture was cooled to 140°C, filtered through a filter (270um) and cooled to room temperature to obtain a filtrate containing a modified polyol product and a filter cake, the filter cake was dissolved in 10 times of methanol and filtered with a slow filter paper with a pore size of 13um, the remaining solid on the filter paper was dried and weighed to 226g, the hydroxyl value of the filter cake was 16mgKOH / g, and the hydroxyl value was 16mgKOH / g. The filtrate is subjected to reduced pressure distillation to remove excess diethylene glycol to obtain 530 g of a modified polyol product having a viscosity greater than 20,000 mPa·s and a brown paste at room temperature. The initial polyurethane content in the modified polyol product is (600-226) / 530=70.6 wt%. The obtained product contains amide groups. According to DIN53176, the amine value of the modified polyol product is 54 mgKOH / g and the hydroxyl value is 156 mgKOH / g. The amine value of the modified polyol product of this embodiment is lower than that of the modified polyol product obtained by the prior art method, indicating that the process optimization of the present invention further has the effect of reducing the amine value of the modified polyol product. Furthermore, the infrared spectrum of the modified polyol product of this embodiment can be measured according to the general rules for infrared spectroscopy analysis methods GB / T 6040. The modified polyol product has an amine value of 54 mgKOH / g and a hydroxyl value of 156 mgKOH / g at 1680 cm -1 ~1780cm -1 、1480cm -1~1570cm -1 and 1100cm -1 ~1210cm -1 There is an infrared absorption peak in the wavenumber range and at 1680 cm -1 ~1780cm -1 The peak height of the infrared absorption peak within the wavenumber range is not less than 1480cm -1 ~1570cm -1 The wavenumber range is 70% of the peak height of the infrared absorption peak.

[0790] The modified polyol product prepared in this example was mixed with PMDI in a weight ratio of 1:1 to prepare a cured polyurethane with uniform quality.

[0791] The modified polyol product can be used to manufacture polyurethane soft foam. Specifically, the modified polyol product can be reacted with a commercially available diisocyanate as a raw material, and a catalyst, a foaming agent, and a foam stabilizer are added. After mixing and stirring, the mixture is foamed and matured. According to the GB / T10802-2023 general soft polyurethane foam plastic test standard, the tensile strength and tensile modulus of the polyurethane soft foam will increase, and the tensile strength, tear strength and rebound rate of the soft foam will increase. Due to its low amine value characteristic, the polyurethane soft foam has good safety.

[0792] Example Gamma-4

[0793] Under nitrogen protection, 80 grams of methyltetrahydrophthalic anhydride, 200 grams of ethylene glycol and 200 grams of NJ204 (hydroxyl value 280) were mixed, then heated to 70°C and stirred for 1 hour to dissolve them evenly to obtain a degradation agent; then 300 grams of polyurethane waste (recycled shoe sole material) was added to the degradation agent, heated and stirred for 6 hours until the polyurethane solid was dissolved, wherein the temperature was maintained in the range of 210°C to obtain a reaction mixture; then the reaction mixture was cooled to 120°C, filtered through a filter (20um) and cooled to room temperature to obtain a mixture containing modified polyurethane. The filtrate and filter cake of the polyol product were dissolved in 10 times the amount of methanol and then filtered with a slow filter paper with a pore size of 13 μm. The remaining solid on the filter paper was dried and weighed to 115 g. The filter cake had a hydroxyl value of 12 mgKOH / g and an amine value of 85 mgKOH / g, which can be used as an active filler for polyols. The filtrate was distilled under reduced pressure to remove excess ethylene glycol to obtain 525 g of a modified polyol product with a viscosity greater than 10,000 mPa·s and a brown paste at room temperature. The initial polyurethane content in the modified polyol product was (300-115) / 525=32.5 wt%. The obtained product contained amide groups. According to DIN 53176, the amine value of the modified polyol product was 45 mgKOH / g and the hydroxyl value was 171 mgKOH / g. The amine value of the modified polyol product of this embodiment was reduced compared to the amine value of the modified polyol product obtained by the prior art method, indicating that the process optimization of the present invention further has the effect of reducing the amine value of the modified polyol product. Furthermore, the modified polyol product of this embodiment can be measured for infrared spectrum according to the general rules for infrared spectrum analysis method GB / T 6040. The modified polyol product has an infrared spectrum at 1680 cm -1 ~1780cm -1 、1480cm -1 ~1570cm -1 and 1100cm -1 ~1210cm -1 The infrared absorption peak has a wave number range of 1680cm-1 to 1780cm-1, and the peak height of the infrared absorption peak in the wave number range of 1480cm-1 is not less than that in the wave number range of 1480cm-1. -1 ~1570cm -1 The wavenumber range is 70% of the peak height of the infrared absorption peak.

[0794] The modified polyol product prepared in this example was mixed with PMDI in a weight ratio of 1:1 to prepare a cured polyurethane with uniform quality.

[0795] The modified polyol product can be used to manufacture elastomers such as polyurethane soles. Specifically, the modified polyol product can be reacted with a commercially available diisocyanate prepolymer as a raw material, and after mixing and stirring, foaming and aging, a polyurethane elastomer is obtained. According to the ASTM D412-16 (2021) elastomer test standard, the tensile strength and tensile modulus of the polyurethane elastomer will increase. Due to its low amine value, the polyurethane elastomer has good safety.

[0796] Example Gamma-5

[0797] Under nitrogen protection, 30 grams of maleic anhydride, 20 grams of succinic anhydride, 30 grams of phthalic acid, 300 grams of ethylene glycol, 300 grams of propylene glycol and 6 grams of tetrabutyl titanate are mixed, then heated to 95° C. and stirred for 1 hour to dissolve evenly to obtain a degradation solution; then 200 grams of polyurethane waste (recycled building insulation rigid foam waste) is added to the degradation solution, heated and stirred for 4 hours until the polyurethane solid is dissolved, wherein the temperature is maintained in the range of 190° C.; then the reaction mixture is cooled to 120° C., filtered through a filter (20 μm) and cooled to room temperature to obtain a filtrate containing a modified polyol product and a filter cake, the filter cake is dissolved in 10 times methanol and then filtered using a slow filter paper with a pore size of 13 μm, the remaining solid on the filter paper is dried and weighed to 85 g, and the hydroxyl value of the filter cake is 17 m gKOH / g, hydroxyl value is 167mgKOH / g, and can be used as an active filler for polyols; the obtained filtrate is subjected to reduced pressure distillation to remove excess propylene glycol to obtain 265g of modified polyol product, with a viscosity greater than 10000mPa·s, and a brown paste at room temperature. The initial polyurethane content in the modified polyol product is (200-85) / 265=43.4wt%. The obtained product contains amide groups. According to DIN53176, the amine value of the modified polyol product is 51mgKOH / g, and the hydroxyl value is 420mgKOH / g. The amine value of the modified polyol product of this embodiment is lower than that of the modified polyol product obtained by the prior art method, indicating that the process optimization of the present invention further has the effect of reducing the amine value of the modified polyol product. Further, the infrared spectrum of the modified polyol product of this embodiment can be measured according to the general rules for infrared spectroscopy analysis methods GB / T 6040. The modified polyol product has an amine value of 51mgKOH / g and a hydroxyl value of 420mgKOH / g. -1 ~1780cm -1 , it has infrared absorption peaks in the wave number ranges of 1480cm-1~1570cm-1 and 1100cm-1~1210cm-1, and the peak height of the infrared absorption peak in the wave number range of 1680cm-1~1780cm-1 is not less than 70% of the peak height of the infrared absorption peak in the wave number range of 1480cm-1~1570cm-1.

[0798] The modified polyol product prepared in this example was mixed with PMDI in a weight ratio of 1:1 to prepare a cured polyurethane with uniform quality.

[0799] The modified polyol product can be used to prepare polyurethane rigid foam.

[0800] Example Gamma-6

[0801] The difference between this embodiment and embodiment Gamma-1 is that: ethylene glycol and initial polyurethane are first mixed uniformly at 190° C. under nitrogen protection, reacted for 8 hours, then cooled to 120° C., maleic anhydride is added, and stirred for 1 hour to obtain a degradation product, and then the reaction mixture is filtered through a filter (60 μm) to obtain a filtrate containing a modified polyol product and a filter cake, the filter cake is dissolved in 10 times methanol and then filtered with a slow filter paper with a pore size of 13 μm, the remaining solid on the filter paper is dried and weighed to be 55 g, and the filter cake is filtered. The cake had an amine value of 11 mgKOH / g and a hydroxyl value of 105 mgKOH / g, and could be used as an active filler in polyols. The filtrate was distilled under reduced pressure to remove excess ethylene glycol, yielding 281 g of a modified polyol product designated MB1C, having a viscosity greater than 20,000 mPa·s and a brown paste at room temperature. The initial polyurethane content in the modified polyol product was (200-55) / 281 = 51.6 wt %, an amine value of 54 mgKOH / g, and a hydroxyl value of 410 mgKOH / g.

[0802] The infrared spectrum of the MB1C modified polyol product was measured according to the general rules for infrared spectroscopy analysis methods GB / T 6040 as shown in Figure 28. The infrared spectrum peak data are shown in Table Gamma-6. It can be found that at 1680 cm -1 ~1780cm - 1 1714.99cm in the wave number range -1 There is an obvious absorption peak at 1090~1210cm -1 1162.00cm in the wavenumber range -1 There is an obvious single absorption peak at 1610 cm -1 and 1480cm -1 ~1570cm -1 1510 cm in the wavenumber range -1 There is also an obvious absorption peak nearby.

[0803] Table Gamma-6: Infrared spectrum peak data of modified polyol product MB1C

[0804] According to Table Gamma-6, the height ratio of the 1713.25 peak to the 1513.07 peak is 1.07 / 1.

[0805] Example Gamma-7

[0806] The difference between this example and example Gamma-2 is that: under nitrogen protection, propylene glycol and initial polyurethane are first uniformly mixed at 180° C. and reacted for 6 hours, then cooled to 120° C., succinic anhydride is added, and stirred for 1 hour to obtain a degradation product, and then the reaction mixture is filtered through a filter (60 μm) to obtain a filtrate containing a modified polyol product and a filter cake, the filter cake is dissolved in 10 times the amount of methanol and then filtered through a slow filter paper with a pore size of 13 μm, and the remaining solid on the filter paper is dried and weighed to 30 g. The filter cake had an amine value of 20 mgKOH / g and a hydroxyl value of 170 mgKOH / g, and could be used as an active filler in polyols. The filtrate was distilled under reduced pressure to remove excess propylene glycol, yielding 265 g of a modified polyol product designated MB1. The product had a viscosity greater than 20,000 mPa·s and was a brown paste at room temperature. The initial polyurethane content in the modified polyol product was (200-30) / 265 = 64.2 wt %. The measured amine value was 51 mgKOH / g, and the hydroxyl value was 397 mgKOH / g.

[0807] The infrared spectrum of the modified polyol product of MB1 measured according to the general rules for infrared spectroscopy analysis methods GB / T 6040 is shown in Figure 29. The infrared spectrum peak data are shown in Table Gamma-7. It can be found that the peak value of the product is between 1680 and 1780 cm -1 1713.12cm in the wave number range -1 There is an obvious absorption peak at 1090~1210cm -1 1177.27cm within the wavenumber range -1 There is an obvious single absorption peak at 1610 cm -1 and 1480~1570cm -1 1510 cm in the wavenumber range -1 There is also an obvious absorption peak nearby.

[0808] Table Gamma-7: Infrared spectrum peak data of modified polyol product MB1

[0809] According to Table Gamma-7, the height ratio of the 1713.25 peak to the 1513.07 peak is 0.98 / 1.

[0810] Example Gamma-8

[0811] The difference between this embodiment and embodiment Gamma-3 is that: under nitrogen protection, diethylene glycol and initial polyurethane are first uniformly mixed at 210° C. and reacted for 18 hours, then the temperature is lowered to 120° C., phthalic anhydride is added, and stirred for 8 hours to obtain a degradation product, and then the reaction mixture is filtered through a filter (60 μm), the filter cake is dissolved in 10 times the amount of methanol, and then filtered with a slow filter paper with a pore size of 13 μm. The remaining solid on the filter paper is dried and weighed to 106 g. The filter cake has an amine value of 21 mgKOH / g and a hydroxyl value of 45 mgKOH / g, which can be used as an active filler for polyols; the filtrate is distilled under reduced pressure to remove excess diethylene glycol to obtain 623 g of degraded polyol, which has a viscosity greater than 20,000 mPa·s and is a brown paste at room temperature. The initial polyurethane content in the modified polyol product is (600-106) / 623=79.3wt%, and the measured amine value is 48 mgKOH / g and the hydroxyl value is 124 mgKOH / g.

[0812] Example Gamma-9

[0813] Under nitrogen protection, 200 grams of ethylene glycol and 200 grams of NJ204 (hydroxyl value 280) were mixed and then heated to 210°C to obtain a degradation agent; 300 grams of polyurethane waste (recycled shoe sole material) was then added to the degradation agent, heated and stirred for 6 hours until the polyurethane solid dissolved, wherein the temperature was maintained in the range of 210°C to obtain a reaction mixture; the reaction mixture was then cooled to 80°C, 80 grams of methyltetrahydrophthalic anhydride was added, stirred for 4 hours, filtered through a filter (60 μm) and cooled to room temperature to obtain a filtrate containing a modified polyol product and a filter cake. The filter cake was dissolved in 10 times methanol and then filtered with a slow filter paper with a pore size of 13 μm. The remaining solid on the filter paper was dried and weighed to 75 g. The hydroxyl value of the filter cake was 16 mgKOH / g, and the amine value was 16 mgKOH / g. The hydroxyl value is 95 mgKOH / g, which can be used as an active filler in polyols. The resulting filtrate is subjected to reduced pressure distillation to remove excess ethylene glycol, yielding 561 g of a modified polyol product with a viscosity greater than 10,000 mPa·s and a brown paste at room temperature. The initial polyurethane content in the modified polyol product is (300-75) / 561 = 40.1 wt%. The resulting product contains amide groups. According to DIN 53176, the amine value of the modified polyol product is 56 mgKOH / g, and the hydroxyl value is 189 mgKOH / g. The amine value of the modified polyol product of this example is lower than that of the modified polyol product obtained by the prior art method, indicating that the process optimization of the present invention further reduces the amine value of the modified polyol product. The modified polyol product obtained in this example is mixed with PMDI in a weight ratio of 1:1 to prepare a uniform quality cured polyurethane.

[0814] Furthermore, the modified polyol product of this embodiment can be measured for infrared spectrum according to the general rules for infrared spectrum analysis method GB / T 6040. The modified polyol product has an infrared spectrum at 1680 cm -1 ~1780cm -1 、1480cm -1 ~1570cm -1 and 1100cm -1 ~1210cm -1 There is an infrared absorption peak in the wavenumber range and at 1680 cm -1 ~1780cm -1 The peak height of the infrared absorption peak within the wavenumber range is not less than 1480cm -1 ~1570cm -1 The wavenumber range is 70% of the peak height of the infrared absorption peak.

[0815] Example Gamma-10

[0816] Under nitrogen protection, 300 grams of ethylene glycol, 300 grams of propylene glycol and 6 grams of tetrabutyl titanate were mixed, then heated to 190°C and stirred for 1 hour to dissolve them evenly to obtain a degradation solution; then 200 grams of polyurethane waste (recycled building insulation rigid foam waste) was added to the degradation solution, heated and stirred for 3 hours until the polyurethane solid dissolved, wherein the temperature was maintained in the range of 190°C; then the reaction mixture was cooled to 50°C, 30 grams of maleic anhydride, 20 grams of succinic anhydride, and 30 grams of phthalic acid were added, stirred for 6 hours, filtered through a filter (60um) and cooled to room temperature to obtain a filtrate containing a modified polyol product and a filter cake, the filter cake was dissolved in 10 times of methanol and filtered with a slow filter paper with a pore size of 13um, the remaining solid on the filter paper was dried and weighed to 38g, and the hydroxyl value of the filter cake was 1:1. The filtrate was subjected to reduced pressure distillation to remove excess propylene glycol and ethylene glycol to obtain 236 g of a modified polyol product having a viscosity greater than 10,000 mPa·s and a brown paste at room temperature. The initial polyurethane content in the modified polyol product was (200-38) / 236 = 68.6 wt%. The product contained amide groups and had an amine value of 48 mgKOH / g and a hydroxyl value of 390 mgKOH / g according to DIN 53176. The amine value of the modified polyol product of this embodiment was lower than that of the modified polyol product obtained by the prior art method, indicating that the process optimization of the present invention further reduces the amine value of the modified polyol product. The modified polyol product obtained in this embodiment was mixed with PMDI in a weight ratio of 1:1 to prepare a cured polyurethane of uniform quality.

[0817] Furthermore, the modified polyol product of this embodiment can be measured for infrared spectrum according to the general rules for infrared spectrum analysis method GB / T 6040. The modified polyol product has an infrared spectrum at 1680 cm -1 ~1780cm -1 、1480cm -1 ~1570cm -1 and 1100cm -1 ~1210cm -1 There is an infrared absorption peak in the wavenumber range and at 1680 cm -1 ~1780cm -1 The peak height of the infrared absorption peak within the wavenumber range is not less than 1480cm -1 ~1570cm -1 The wavenumber range is 70% of the peak height of the infrared absorption peak.

[0818] Comparative Example Gamma-1

[0819] Under nitrogen, 300 grams of diethylene glycol was heated to 80°C, followed by the addition of 600 grams of polyurethane waste (recycled polyurethane flexible foam). The mixture was heated and stirred for 18 hours until the polyurethane solids dissolved, maintaining the temperature within the range of 210°C. The mixture was then cooled to 80°C, filtered through a 30 μm filter, and cooled to room temperature. The resulting filtrate was then distilled under reduced pressure to remove excess diethylene glycol, yielding a modified polyol product. The amine value of the modified polyol product was measured to be 270 mgKOH / g, and the hydroxyl value was 119 mgKOH / g.

[0820] Comparative Example Gamma-2

[0821] Under nitrogen, 800 grams of ethylene glycol was heated to 50°C. 200 grams of polyurethane waste (recycled refrigerator rigid foam) was then added and heated with stirring for 16 hours until the polyurethane solids dissolved, maintaining the temperature within the 190°C range. The mixture was then cooled to 120°C, filtered through a 60 μm filter, and cooled to room temperature. The resulting filtrate was then distilled under reduced pressure to remove excess ethylene glycol, yielding a modified polyol product. The amine value of the modified polyol product was measured to be 235 mgKOH / g, and the hydroxyl value was 537 mgKOH / g.

[0822] Comparative Example Gamma-3

[0823] Under nitrogen protection, 80 grams of maleic anhydride, 28 grams of water and 800 grams of ethylene glycol were mixed, then heated to 150°C and stirred for 90 minutes to dissolve them evenly; then 200 grams of polyurethane waste (recycled refrigerator rigid foam) was added, and heated and stirred for 16 hours until the polyurethane solid dissolved, with the temperature maintained in the range of 160°C; then cooled to 120°C and filtered through a filter (60μm), but filtration was very difficult and normal process operation could not be achieved.

[0824] Comparative Example Gamma-4

[0825] 80 grams of maleic anhydride, 28 grams of water, and 800 grams of ethylene glycol were mixed, heated to 150°C, and stirred for 90 minutes to uniformly dissolve. 200 grams of polyurethane waste (recycled refrigerator hard foam) was then added, and the mixture was heated and stirred for 20 hours until the polyurethane solids dissolved, with the temperature maintained at 180°C. The mixture was then cooled to 120°C, filtered through a 60 μm filter, and if difficult to filter, filtered through a 300 μm filter and cooled to room temperature. The resulting filtrate was then distilled under reduced pressure to remove excess ethylene glycol to obtain a modified polyol product. The amine value of the resulting modified polyol product was determined to be 19 mgKOH / g and the hydroxyl value was 389 mgKOH / g according to DIN 53176.

[0826] Comparative Example Gamma-5

[0827] 80 grams of maleic anhydride, 370 grams of diethylene glycol, and 20 grams of water were mixed and heated to 150°C over 90 minutes with stirring for dissolution. 400 grams of polyurethane waste (recycled polyurethane soft foam material) were then added and heated with stirring for 16 hours until the polyurethane solid dissolved, wherein the temperature was maintained at 180°C. 20 grams of water were added during the polyurethane solid dissolution process, and after stirring for another hour, 70 grams of ethylene glycol were added, followed by stirring at 220°C for 1 hour. 20 grams of phthalic anhydride were then added, and while stirring was maintained, 20 grams of dipropylene glycol were added after 10 minutes. Stirring was continued at 220°C for half an hour, and then stirring was continued until the mixture was cooled to 80°C to obtain a reaction mixture. The reaction mixture was filtered through a 60 μm filter, but filtration was very difficult and normal process operation could not be achieved.

[0828] Comparative Example Gamma-6

[0829] 80 grams of maleic anhydride, 370 grams of diethylene glycol and 20 grams of water were mixed and heated to 150°C and stirred for dissolution within 90 minutes. Then, 400 grams of polyurethane waste (recycled polyurethane soft foam material) was added and heated with stirring for 25 hours until the polyurethane solid dissolved, wherein the temperature remained in the range of 210°C. During the polyurethane solid dissolution process, 20 grams of water were added simultaneously. After stirring for another hour, 70 grams of ethylene glycol were added and then stirred at 220°C for 1 hour. Then, 20 grams of phthalic anhydride was added. While stirring was maintained, 20 grams of dipropylene glycol was added after 10 minutes. Stirring was continued at 220°C for half an hour, and then stirring was continued until it was cooled to 80°C to obtain a reaction mixture. The reaction mixture was filtered through a filter (60 μm). If the reaction mixture was difficult to filter, it was filtered through a filter (200 μm). The filtrate was distilled under reduced pressure to remove excess alcoholysis agent to obtain a modified polyol product. The amine value of the modified polyol product was determined to be 23 mgKOH / g and the hydroxyl value was 95 mgKOH / g according to DIN 53176.

[0830] Comparison of Examples Gamma-1 to 10 and Comparative Examples Gamma-1 to 2 shows that if anhydride is not used to participate in the degradation reaction, the amine value of the resulting alcoholysis-modified polyol product is relatively high, resulting in not only toxicity of the modified polyol product but also excessively rapid reaction with isocyanate, poor process operability, and hindrance to subsequent adjustment of the combined material formula and product preparation.

[0831] Comparison of Examples Gamma-1 to Gamma-9 and Comparative Examples Gamma-3 to Gamma-4 reveals that, although the addition of anhydride can effectively reduce the amine value of the degraded modified polyol product, the reaction system in which water is added still results in an excessively large particle size of the resulting modified polyol product, even if the process flow is increased as shown in Comparative Examples Gamma-5 to Gamma-6. The small particle size of the modified polyol products of Examples Gamma-1 to Gamma-8 facilitates filtration during the production process and subsequent formulation operations.

[0832] The modified polyol product obtained by degrading polyurethane waste according to the method of the present invention can be used as a degraded polyol, which can be used in a weight ratio (degraded polyol / ordinary polyol) of 5 / 95 to 55 / 45 and mixed with ordinary polyols (i.e., polyols obtained by conventional industrial ring opening of ethylene oxide, propylene oxide or butane, or polyester polyols, etc.) to prepare a new polyurethane product in combination, and its performance is not significantly reduced compared with the original polyurethane product (i.e., without adding any recycled polyols).

[0833] Taking the modified polyol product obtained in Example Gamma-1 (measured hydroxyl value 360 ​​mgKOH / g) as an example, the degraded polyol obtained from the degradation reaction was mixed with a conventional polyol in a certain proportion to prepare rigid foam products, and the corresponding rigid foam properties were tested. The conventional polyether polyol was selected from Jurong Ningwu NJ-303, 44V20 was selected from Covestro Polymers, catalysts PC-5, T9, and TMR-2 were selected from Air Products, cyclopentane was commercially available, and the surfactant was selected from Meside. Three rigid foam products were prepared according to the ratios shown in Table Gamma-8.

[0834] Table Gamma-8: Formula ratio of rigid foam products

[0835] The physical properties of rigid foam products are tested based on the GBT40363-2021 standard. The specific results are shown in Table Gamma-9 below.

[0836] Table Gamma-9: Physical property test results of Examples Gamma-1a, 1b and Comparative Example Gamma-1c

[0837] As can be seen from Table Gamma-9, the degraded polyols of Examples Gamma-1a and 1b can replace a portion of conventional polyol products for the manufacture of new polyurethane products. Furthermore, the physical properties achieved are similar to those of conventional polyol products. This fully utilizes the recycled products in new products, helps reduce production costs, further increases the advantages of waste recycling, and provides strong support for environmental protection.

[0838] The technical point of the fourth part of the present invention is that the polyurethane solid can be alcoholyzed by only adding anhydride. The resulting modified polyol product has two advantages: (1) small particle size and easy filtration; (2) low amine value. This method effectively solves the problem of high amine value in traditional polyurethane alcoholysis methods. Although there are methods reported to add anhydride to reduce the amine value of polyurethane solid alcoholysis products, it is often required that the added anhydride must be used together with water rather than alone. Secondly, the anhydride, water, polyol and small molecule alcohol must be added stepwise multiple times during the degradation process to achieve the purpose of reducing the amine value of the alcoholysis product. Not only does it increase the complexity of the process steps, but the particle size of the resulting degradation product is also large, which is not conducive to separation and subsequent use.

[0839] The fourth part of the present invention innovatively discovers that adding anhydride at the beginning of the alcoholysis process simplifies the process and directly reduces the amine value of the alcoholysis product. Furthermore, the present invention eliminates the need for the additional addition of water. If both anhydride and water are used (Comparative Examples Gamma-3 to Gamma-6), the resulting modified polyol product has a very large particle size, which is unfavorable for separation and subsequent use.

[0840] Part V: Derivative Example Group Delta-Toughening Agents and Modified Resins

[0841] Part V Aspect 1

[0842] The first aspect of the fifth part of the present invention relates to a toughening auxiliary agent and a modified epoxy resin. Alcoholysis recovery of polyurethane solid materials is one of the most commonly used chemical recovery methods for polyurethane degradation and recovery. Polyurethane solid materials include alcoholysis of solids such as polyurethane solid waste, scraps generated during the production of polyurethane products, retired polyurethane materials (refrigerator container insulation rigid foam, mattress sofa soft foam, sole materials, polyurethane elastomers, polyurethane semi-rigid foam, polyurethane adhesives, etc.) and polyurethane composite materials (window frames, beams, solar frames, sleepers, cable boxes, battery shells, brackets, etc.).

[0843] But the alcoholysis of these solid polyurethanes, comprise the alcoholysis of various polyurethane solid wastes (soft foam, hard foam, semi-hard foam, elastomer, adhesive, cast body, composite material etc.), recycling under normal circumstances is only the polyol product obtained by polyurethane degradation, again by back-mixing mode in common polyol (i.e. conventional industrialization according to the polyol of open-loop gained such as ethylene oxide, propane or butane, or polyester polyol etc.) component with a certain proportion, re-prepare all kinds of polyurethane products, such as foam, elastomer, adhesive etc..This recycling mode is only to focus on the polyol product obtained by the complete degradation of polyurethane and not do more further research and effectively utilize to other component relevant to isocyanate, and can generate new waste again in the purification process of degraded polyol product.Therefore this recycling mode institute's recovered product accounts for the useful ratio of solid waste on the low side, and economic value is limited, and purposes is also limited, is unfavorable for the economic and efficient recycling of polyurethane solid waste.

[0844] Commonly used thermosetting resins are widely used in our daily lives. While they offer the advantages of high strength, they also come with the disadvantages of low toughness and brittleness. Therefore, how to maintain the high strength of thermosetting resins while overcoming their shortcomings in toughness has always been a key requirement.

[0845] The fifth purpose of the present invention is to provide a resin intermediate, a thermosetting resin product and a preparation method thereof, such as epoxy resin, vinyl resin, unsaturated resin, etc., which uses initial polyurethane for degradation, thereby improving the recycling rate of polyurethane solid waste and achieving the purpose of improving the toughness of thermosetting resin products. To solve the above technical problems:

[0846] The present invention also provides a method for preparing a toughening additive, comprising the following steps:

[0847] Step A: subjecting the initial polyurethane to a degradation reaction with a degradation agent having an active group, thereby breaking at least a portion of the molecular chains of the initial polymer to obtain a polyol product containing molecular fragments of the initial polymer;

[0848] Step B: performing a ring-opening reaction on the cyclic acid anhydride and the polyol product to obtain a toughening agent containing a carboxyl group.

[0849] Furthermore, in step B, the cyclic acid anhydride includes one or more combinations of monofunctional acid anhydride, difunctional acid anhydride or free acid anhydride.

[0850] Furthermore, in step B, the cyclic anhydride includes one or more combinations of succinic anhydride, maleic anhydride, phthalic anhydride, nadic anhydride, methylhexahydrophthalic anhydride, chlorendic anhydride, pyromellitic anhydride or trimellitic anhydride;

[0851] The ring-opening reaction is as follows:

[0852] in, represents the polyol product, represents a cyclic anhydride, represents a toughening agent, R1, R2, R3, and R4 are H, C1-C16 alkyl, cycloalkyl, alkenyl, cycloalkenyl, or aromatic groups (wherein R2 and R3 can be connected to form a ring called a cycloalkyl, aromatic ring, etc., such as structures such as methyltetrahydrophthalic anhydride and phthalic anhydride). The active hydrogen (hydroxyl and amino) in the polyol product is converted into an ester bond and an amide bond respectively by ring opening with anhydride, and the other end of the bond is the carboxyl group obtained by ring opening with anhydride, thereby obtaining a carboxyl derivative toughening agent. The present invention has found that there are multiple options for the structure of the toughening agent in organic chemical reactions, but the method of ring opening with anhydride is the most concise and effective way to solve the technical problem in the present invention.

[0853] Furthermore, when the two carbonyl groups of the cyclic anhydride are connected by a carbon-carbon unsaturated double bond, there are no R1 and R4, only R2 and R3 groups, and R2 and R3 groups can still be H, C1-C16 alkyl, cycloalkyl, cycloalkenyl, alkenyl, aromatic groups, etc. (where R2 and R3 can be connected to form a ring called a cycloalkyl, aromatic ring, etc., such as structures such as methyltetrahydrophthalic anhydride and phthalic anhydride). Cyclic anhydride becomes This representative structure. The above anhydride ring-opening reaction can be represented by the following general formula:

[0854] in, represents the polyol product, is a cyclic anhydride, Stands for toughening additive.

[0855] Furthermore, during the ring-opening reaction, it is not ruled out that some cis-anhydride structures will be converted into trans structures.

[0856] The ring-opening reaction of active hydrogen (hydroxyl or amino) with cyclic anhydrides is a common reaction in organic chemistry. The two reaction equations above are merely schematic diagrams to illustrate that the reaction product has a newly formed ester or amide bond at one end and a newly formed carboxylic acid group at the other. For example, the following structure is obtained using phthalic anhydride:

[0857] In the ring-opening reaction of the active hydrogen (hydroxyl or amino) of the polyol product with these cyclic anhydrides, due to steric hindrance and other reasons, some hydroxyl or amino groups will not participate in the reaction and remain in the form of active hydrogen, but this will not affect the efficacy of the final product as a toughening agent.

[0858] Furthermore, in step A, the degradation reaction is an alcoholysis reaction.

[0859] Furthermore, the degradation agent includes polyols, and the polyols include diols and / or high-functionality polyols.

[0860] Furthermore, the diol includes a low molecular weight C2-C6 diol.

[0861] Furthermore, the low molecular weight C2-C6 diol includes one or a combination of ethylene glycol, propylene glycol, 1,4-butanediol, ethylene glycol ether, propylene glycol ether or neopentyl glycol.

[0862] Furthermore, the high-functionality polyol includes glycerol, trimethylolethane, pentaerythritol, sucrose polyol, sorbitol or polyether polyol.

[0863] Furthermore, the alcoholysis reaction temperature is 110-150° C., 150-170° C., 170-180° C., 180-200° C., 200-220° C., or 220-250° C. Preferably, the alcoholysis reaction temperature is 150-220° C.; more preferably, the alcoholysis reaction temperature is 170-220° C.

[0864] Furthermore, the alcoholysis reaction time is 0.5 to 2 hours, 2 to 3 hours, 3 to 6 hours, 6 to 12 hours, 12 to 24 hours, 24 to 48 hours or 48 to 64 hours. Preferably, the alcoholysis reaction time is 0.5 to 6 hours; more preferably, the alcoholysis reaction time is 0.5 to 3 hours.

[0865] Alcoholysis reaction among the present invention is that polyurethane solid material is added alcohols degradation agent (middle and long chain polyol, small molecule polyol etc.), then by the mode of heating, its interior macromolecular chain is degraded and its depolymerization is become the liquid polyol material containing polyhydroxyl and amino.These liquid polyol materials can be directly reused as the polyol product of doping recovery, also can before being reused, first through further separation, purification and classification, for example deamination, removal particle etc.Actual alcoholysis process can add a certain amount of co-alcoholization agent and / or catalyzer etc. according to specific needs, for example one or more combinations in amine, phosphoric acid ester, alcoholamines, alkali metal and alkaline earth metal carboxylate and hydroxide or other metallic salt (tin, titanium etc.).

[0866] Furthermore, in step B, the temperature of the ring-opening reaction is 40-60° C., 60-80° C., 80-100° C., 100-120° C., 120-130° C., 130-140° C., 140-160° C., 160-180° C. or 180-200° C. Preferably, the temperature of the ring-opening reaction is 100-160° C.; more preferably, the temperature of the ring-opening reaction is 100-140° C.

[0867] Furthermore, the ring-opening reaction time is 0.5 to 2 hours, 2 to 3 hours, 3 to 6 hours, 6 to 12 hours, 12 to 24 hours or 24 to 48 hours. Preferably, the ring-opening reaction time is 2 to 12 hours, more preferably, the ring-opening reaction time is 3 to 6 hours.

[0868] The fifth part of the present invention also provides a toughening aid obtained by the preparation method of any of the above toughening aids.

[0869] Furthermore, the toughening aid obtained by any of the above-mentioned methods for preparing the toughening aid is used to prepare a modified epoxy resin.

[0870] The inventors unexpectedly discovered that the degraded polyurethane material obtained by alcoholysis, namely the polyol product, does not require additional separation and purification, but can be directly modified with carboxyl functional groups through a simple chemical reaction. This alcoholysis product modified with carboxyl functional groups can be used as a toughening agent to toughen anhydride-cured epoxy resin, and while improving its toughness, it does not damage other properties of the epoxy resin.

[0871] The fifth part of the present invention also provides a method for preparing a modified epoxy resin using any of the above toughening additives, comprising the following steps:

[0872] Step C: uniformly mixing the epoxy resin, the acid anhydride curing agent, the toughening agent and the catalyst to obtain a mixture;

[0873] Step D: heating and curing the mixture,

[0874] Step E: Cooling the heated and cured mixture to obtain the modified epoxy resin.

[0875] Furthermore, in step C, the weight percentage of the toughening agent to the anhydride curing agent is 3 to 75%;

[0876] The fifth part of the present invention also provides a modified epoxy resin obtained by any one of the above methods for preparing a modified epoxy resin.

[0877] The fifth part of the present invention provides a new toughening agent system in an innovative way. It can be introduced into the anhydride / epoxy system in a certain proportion by direct addition. It achieves the toughening effect without affecting the other properties of the cured epoxy resin, effectively overcoming the pain points of existing toughening agent systems and meeting the needs of the industry. The resulting modified epoxy resin has similar application scenarios as conventional epoxy resins, including but not limited to the preparation of various composite materials such as blade components, window frames, frames, various pultruded profiles, cable boxes, various parts of automobiles and ships, sports and leisure products, etc. through infusion, pultrusion, winding, spraying, hand lay-up, prepreg, SMC / BMC and other process methods.

[0878] The fifth part of the present invention is based on the use of a degraded polyurethane product obtained from polyurethane as a polyol product. The polyol product usually contains active hydrogens such as hydroxyl groups and amino groups. Cyclic acid anhydride is added to cause a ring-opening reaction with the active hydrogen (hydroxyl groups, amino groups) in the polyol product to obtain a substance containing terminal carboxyl groups, which can be used as a toughening auxiliary component. Moreover, the toughening auxiliary component can be used as an epoxy resin toughening auxiliary component and added to an epoxy system cured by anhydride. It can not only improve the toughness of the cured epoxy resin, but also will not affect other properties of the resin, such as heat resistance and strength.

[0879] The raw materials used in the specific implementation methods of the first aspect described in Part V can be purchased commercially. Liquid nitrile rubber DY-065 was purchased from Guangzhou Weilina Chemical Co., Ltd.; epoxy resin 127 was purchased from Nanya Chemical; various anhydride curing agents were purchased from Alibaba.com; and other reagents were purchased from Sinopharm or Alibaba.com.

[0880] First, a specific implementation method for the preparation of a toughening agent is provided, which includes the following steps: Step A: subjecting the initial polyurethane to a degradation reaction with a degradation agent having an active group to break the molecular chain of at least a portion of the initial polymer to obtain a polyol product containing molecular fragments of the initial polymer; Step B: subjecting the cyclic acid anhydride to a ring-opening reaction with the polyol product to obtain a toughening agent containing a carboxyl group.

[0881] The detailed test process and results of Examples Delta-1 to Delta-3 are given below for illustrative purposes:

[0882] Example Delta-1

[0883] Step 1: Take 300 grams of polyurethane waste (post-consumer container rigid foam) and 600 grams of ethylene glycol, add 0.3 grams of catalyst tetrabutyl titanate, and then heat and stir until the polyurethane solid dissolves to perform a degradation reaction, wherein the temperature is maintained in the range of 190°C (170°C-220°C) to obtain a degradation reaction liquid.

[0884] Step 2: After cooling the degradation reaction liquid to 120° C., the undegraded solid residue was separated by filtration. The filtrate was subjected to reduced pressure distillation to remove excess ethylene glycol to obtain the polyol product Delta-A1. The hydroxyl value of the obtained polyol product Delta-A1 was 450 mgKOH / g, as determined according to ASTM E1899-2016.

[0885] Step 3: Take 100 grams of the polyol product Delta-A1, add 80 grams of succinic anhydride, 2 grams of catalyst p-toluenesulfonic acid and 200 ml of dimethyl sulfoxide, and carry out a ring-opening reaction at 120°C for 6 hours. Remove the solvent dimethyl sulfoxide by vacuum distillation to obtain the target product, the toughening agent Delta-S1.

[0886] Example Delta-2

[0887] Step 1: 400 g of polyurethane waste (post-consumer polyurethane soft foam material), 100 g of polyurethane waste (post-consumer refrigerator hard foam) and 300 g of diethylene glycol are mixed, and then heated and stirred until the polyurethane solid is dissolved to perform a degradation reaction, wherein the temperature is maintained in the range of 190° C. (160° C.-210° C.) to obtain a degradation reaction liquid.

[0888] Step 2: The degradation reaction solution was cooled to 50°C and filtered to remove any undegraded solid residue. The resulting filtrate was then distilled under reduced pressure to remove excess diethylene glycol to obtain the polyol product Delta-A2. The resulting polyol product Delta-A2 had a hydroxyl number of 270 mgKOH / g, as determined according to ASTM E1899-2016.

[0889] Step 3: Take 100 grams of the polyol product Delta-A2, add 28 grams of maleic anhydride and 28 grams of phthalic anhydride, 2 grams of p-toluenesulfonic acid and 200 ml of dimethyl sulfoxide, and carry out a ring-opening reaction at 120°C for 6 hours. The solvent ...

Claims

1. A modified polymer, characterized in that The modified polymer is obtained by treating the initial polymer, wherein the treatment comprises the following steps: Step A: subjecting the initial polymer to a degradation reaction with a degradation agent having an active group, thereby breaking at least a portion of the molecular chains of the initial polymer and obtaining a resin intermediate containing molecular fragments of the initial polymer and the active group; The initial polymer includes a thermoplastic polymer with a linear or branched molecular structure and a thermosetting polymer with a cross-linked network molecular structure, and the molecular weight of the initial polymer is not less than 10000 g / mol.

2. The modified polymer according to claim 1, characterized in that The initial polymer includes pure polymer and polymer composite, the polymer composite contains filler and / or fiber, the filler includes solid or liquid additives that do not chemically react with the initial polymer.

3. The modified polymer according to claim 1, characterized in that In the step A, the initial polymer molecular chain carries a chain-breaking group, and in the step A, the molecular chain of the initial polymer is broken from the chain-breaking group.

4. The modified polymer according to claim 1, characterized in that In step A, the degradation agent carries a chain extension group having a chain growth or cross-linking function, and the chain extension group can react with other groups or itself to achieve molecular chain growth or cross-linking.

5. The modified polymer according to claim 4, characterized in that The degradation agent contains at least one active group, which includes a combination of one or more of a hydroxyl group, an amide group, an acyl salt group, a urea group, an amine group, a carboxyl group, an anhydride group, a carboxylate group, an unsaturated double bond or triple bond, an ester group, a cyano group, a nitro group, a carbonyl group or an epoxy group.

6. The modified polymer according to claim 2, characterized in that In step A, the chain-breaking group includes one or more combinations of -N(H)n-, -NH-(CO)-O-, -C=C-, -C≡C-, -O-, -HN-(CO)-NH-, -(CO)-NH-, -NH-(CS)-O-, -C=C-, -S-, -HN-(CS)-NH-, -(CS)-NH-, heterocycle, cyclic ring, aromatic ring, hexyl ring, macrocycle, polyhedron, isomer or polypeptide.

7. The modified polymer according to claim 1, characterized in that After the step A is completed, there is a step of removing at least a portion of the degradation agent and / or solvent that has not participated in the reaction.

8. The modified polymer according to claim 1, characterized in that The initial polymer includes at least one polymer waste that has lost its use function, or the resin intermediate is prepared by compounding multiple resin intermediates made from the initial polymer.

9. The modified polymer according to any one of claims 1 to 8, characterized in that In step A, the initial polymer includes a thermoplastic polyurethane having a linear or branched molecular structure and / or a thermosetting polyurethane having a cross-linked network molecular structure; the degradation reaction includes a combination of one or more of pyrolysis, hydrolysis, alcoholysis, esterification, transesterification, aminolysis, acidolysis, alkaline hydrolysis, alcohol-alkali reaction, hydrogenolysis or acylation reaction.

10. The modified polymer according to claim 9, characterized in that The degradation agent is an alcoholysis agent, and the degradation agent includes a polyol, and the polyol includes a diol and / or a high-functionality polyol; the alcoholysis reaction temperature is 110-150°C, 150-170°C, 170-180°C, 180-200°C, 200-220°C or 220-250°C; the alcoholysis reaction time is 0.5-2h, 2-3h, 3-6h, 6-12h, 12-24h, 24-48h or 48-64h; the alcoholysis reaction yield is 50-60%, 60-70%, 70-80%, 80-95% or 95-100%; the resin intermediate has a number average molecular weight measured by two detectors, RID and VWD (254nm), ranging from 150 to 200; 200 to 350; 350 to 700; 700~1000, 700~1000, 1000~1800, 1800~3000, 3000~5000, 5000~10000, 10000~30000 or 30000~60000 g / mol; the viscosity at room temperature (25°C) is 50~200 mPa·s, 200~500 mPa·s, 500~10 00mPa·s, 1000~2000mPa·s, 2000~10000mPa·s, 10000~20000mPa·s, 20000~600 00mPa·s, 60000~200000mPa·s, 200000~600000mPa·s or 600000~1800000mPa·s.

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