Resin intermediate, thermosetting resin product and preparation method thereof

Abstract

The invention discloses a resin intermediate, a thermosetting resin product and a preparation method thereof, and the preparation method comprises the following steps: step 1, carrying out degradation reaction on an initial polymer and a degradation agent with an active group to break at least a part of molecular chains of the initial polymer, preparing a resin intermediate containing an initial polymer molecular chain fragment with an active group; the initial polymer is initial polyurethane; in the step A, the degradation reaction is alcoholysis reaction, the degradation agent comprises polyhydric alcohol, and the polyhydric alcohol comprises dihydric alcohol and / or high-functionality polyhydric alcohol. The polyhydric alcohol product (namely the resin intermediate) obtained after degradation of the polyurethane waste is used for preparing the thermosetting resin product, toughness can be improved, the polyhydric alcohol product can be introduced into various thermosetting resin systems according to a certain proportion in a direct adding mode, the toughening effect is achieved, other properties of the cured thermosetting resin cannot be affected, and the thermosetting resin product is suitable for large-scale popularization and application. The pain point of an existing flexibilizer system is effectively overcome, and the requirements of the industrial circle are met.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a resin intermediate, a thermosetting resin product and a preparation method thereof. Background Art

[0002] Alcohol hydrolysis recovery of polyurethane solid materials is one of the most commonly used chemical recycling methods for polyurethane degradation and recycling. Polyurethane solid materials include 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.) and other solid alcoholysis.

[0003] But the alcoholysis of these solid polyurethanes, including the alcoholysis of various polyurethane solid wastes (soft foam, hard foam, semi-hard foam, elastomer, adhesive, cast body, composite material, etc.), the recycling under the normal situation is only the polyol product obtained by polyurethane degradation, and then by a certain proportion in common polyol (i.e. conventional industrialization according to the polyol obtained by ring opening such as ethylene oxide, propane or butane, or polyester polyol, etc.) The mode of back-mixing, re-preparing various types of polyurethane products, such as foam, elastomer, adhesive, etc.. This recycling mode is only focused on the polyol product obtained by the complete degradation of polyurethane and other components related to isocyanate are not further studied and effectively utilized, and new waste can be generated again in the purification process of the degraded polyol product. Therefore, the product recovered by this recycling mode accounts for a low useful ratio of solid waste, and the economic value is limited, and the purposes are also limited, which is unfavorable for the economic and efficient recycling of polyurethane solid waste.

[0004] Various commonly used thermosetting resins are widely used in our daily lives. They usually have the advantage of high strength, but also have the disadvantages of low toughness and brittleness. Therefore, how to retain the high strength of thermosetting resins while overcoming the disadvantage of poor toughness has always been an important demand. Summary of the invention

[0005] The 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, on the one hand to improve the recycling rate of polyurethane solid waste, and on the other hand to achieve the purpose of improving the toughness of thermosetting resin products.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for preparing a resin intermediate comprises the following steps: step A: subjecting an initial polymer to a degradation reaction with a degradation agent having an active group, breaking at least a portion of the molecular chain of the initial polymer, and obtaining a resin intermediate containing molecular chain fragments of the initial polymer having the active group; the initial polymer is an initial polyurethane; in step A, the degradation reaction is an alcoholysis reaction, the degradation agent comprises a polyol, and the polyol comprises a diol and / or a high-functionality polyol.

[0008] Furthermore, the initial polyurethane is polyurethane solid waste, and the diol includes low molecular weight C2-C6 diol.

[0009] Further, 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;

[0010] Further, the low molecular weight C2-C6 diol includes one or more combinations of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, diethylene glycol, dipropylene glycol, ethylene glycol ketone, propylene glycol ketone or neopentyl glycol.

[0011] Further, the high-functionality polyol includes glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, sucrose polyol, sorbitol or polyether polyol.

[0012] Further, the temperature of the alcoholysis reaction is 110-150°C, 150-170°C, 170-180°C, 180-200°C, 200-220°C or 220-250°C.

[0013] Furthermore, the alcoholysis reaction time is 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.

[0014] The present invention claims protection for the resin intermediate prepared by any one of the above methods.

[0015] Furthermore, the resin intermediate is used to manufacture thermosetting resin products and to improve the toughness of the thermosetting resin products, that is, it can be used as a toughening aid, and can also be called a toughness improving modifier or a high-toughness cross-linking agent, etc. Thermosetting resin products are thermosetting resin products, and the thermosetting resin products are epoxy resins, unsaturated resins or vinyl resins.

[0016] The resin intermediate obtained by degradation reaction can be used to manufacture thermosetting resin products with improved toughness, coatings, adhesives, structural adhesives and other chemicals, including PU rigid foams, soft foams, elastomers, composite materials, epoxy resin crosslinking agents, epoxy resins, unsaturated resins, vinyl resin modifiers and crosslinking agents for polyurethane rubbers.

[0017] The present invention further claims to protect the use of any one of the resin intermediates in improving the toughness of thermosetting resin products, wherein the thermosetting resin products are epoxy resins, unsaturated resins or vinyl resins.

[0018] Alcoholysis reaction in the present invention is to add alcohol degradation agent (middle and long chain polyol, small molecule polyol etc.) to the polyurethane solid material, and then degrade the macromolecular chain in it by heating mode to make it depolymerize into the liquid polyol material (i.e. resin intermediate) containing polyhydroxyl and amino. These liquid polyol materials can be directly reused as the polyol product of doping recovery, and can also be reused before further separation, purification and classification, such as deamination, removal of particles etc. The actual alcoholysis process can add a certain amount of co-alcoholization agent and / or catalyst etc. according to specific needs, such as one or more combinations in amines, phosphates, alcoholamines, alkali metal and alkaline earth metal carboxylates and hydroxides or other metal salts (tin, titanium etc.).

[0019] The present invention further provides a method for preparing a modified epoxy resin based on a resin intermediate prepared by any one of the above methods, comprising the following steps:

[0020] Step A1: uniformly mixing epoxy resin, curing agent and resin intermediate to obtain epoxy mixture;

[0021] Step A2: Heat and cure the epoxy mixture.

[0022] Step A3: Cooling the epoxy mixture after heating and curing to obtain a modified epoxy resin.

[0023] Furthermore, the modified epoxy resin can be used as a semi-curing material to participate in the preparation of derivatives such as thermosetting epoxy composites.

[0024] In step A1, the resin intermediate accounts for 1-2%, 2-3%, 3-5%, 5-10%, 10-15%, 15-20%, 20-25%, 25-30%, 30-35% or 35-40% of the total weight of the epoxy mixture;

[0025] In step A2, the temperature of heating and curing is 10-60°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.

[0026] In step A3, the epoxy mixture after heating and curing is cooled to below 50° C.; preferably, it is cooled to below 35° C. and stored.

[0027] Furthermore, step A1 further includes: uniformly mixing the epoxy resin, the curing agent, the resin intermediate and the catalyst to obtain an epoxy mixture.

[0028] Furthermore, the curing agent is a compound that can react with the chain extending group, or a compound that can induce the chain extending group to react with each other.

[0029] Furthermore, the reactive functional groups of the compound for reacting include one or a combination of free radical initiators, isocyanate groups, acid anhydrides, carboxyl groups, epoxy groups, amine groups, amide groups or aldehydes.

[0030] Furthermore, the curing agent also includes an accelerator compatible with the free radical initiator;

[0031] The accelerator includes metal salts, organic amines, including cobalt salts, copper salts, zinc salts or aniline accelerators.

[0032] Furthermore, the curing agent contains anhydride or amine reactive functional groups.

[0033] The present invention further claims protection for the modified epoxy resin prepared by any one of the above methods.

[0034] Furthermore, the impact strength of the modified epoxy resin is increased by at least 20%, 30%, 40%, 50%, 60%, 70% or 80% relative to the epoxy resin; the tensile elongation at break of the modified epoxy resin is increased by at least 8%, 15%, 20%, 30%, 40%, 50%, 75% or 100% relative to the epoxy resin.

[0035] The characteristic of epoxy resin material is high strength, but poor toughness, belonging to high-strength thermosetting resin with large brittleness. Therefore, the toughening of epoxy resin has been one of the most urgent needs of its application field. The toughening of epoxy resin, except transforming the molecular structure of epoxy itself to increase the toughness of its cured product, the most effective method is to add various toughening aids, such as adding auxiliary agents such as core-shell particles, rubber particles, liquid rubber, thermoplastic resin to effectively improve the toughness of epoxy, but these toughening aids can also significantly reduce the heat resistance of epoxy at the same time. Therefore, in the epoxy industry, excellent toughening aids are always sought, which can effectively improve the toughness of epoxy, and can not reduce the performances such as strength and heat resistance. The present invention is surprisingly found that the degraded polyurethane material obtained based on the alcoholysis mode is used as a polyol product (i.e., resin intermediate), and does not need to be separated and purified through extra separation, just can be directly used as a toughening agent to improve the toughening of epoxy resin, and can not damage other properties of epoxy resin while improving its toughness. The present invention is based on the use of a degraded polyurethane product obtained from an initial polyurethane as a polyol product. The polyol product generally contains active hydrogen such as hydroxyl groups and amino groups. The polyol product can be used as an epoxy resin toughening agent and added to an epoxy system cured by amines and anhydrides. It can improve the toughness of the cured epoxy resin while not affecting other properties of the resin, such as heat resistance and strength.

[0036] The present invention provides a new toughening agent system in an innovative way, which can be introduced into the epoxy system in a certain proportion by direct addition, achieving the toughening effect without affecting other properties of the cured epoxy resin, effectively overcoming the pain points of the existing toughening agent system and meeting the needs of the industry. And the obtained modified epoxy resin has similar application scenarios as conventional epoxy resin, including but not limited to preparing various composite materials by infusion, pultrusion, winding, spraying, hand lay-up, prepreg, SMC / BMC and other process methods, such as blade parts, window frames, frames, various pultruded profiles, cable boxes, various parts of automobiles and ships, sports and leisure products, etc.

[0037] The present invention further provides a method for preparing a modified vinyl resin using a resin intermediate prepared by any one of the above methods, comprising the following steps:

[0038] Step B1: uniformly mixing a vinyl resin, a free radical initiator, a resin intermediate and an accelerator to obtain a resin mixture;

[0039] Step B2: Heat and cure the resin mixture.

[0040] Step B3: Cooling the heated and cured resin mixture to obtain a modified vinyl resin.

[0041] Furthermore, the modified vinyl resin can be used as a semi-cured material to participate in the preparation of derivatives such as thermosetting vinyl resin composites.

[0042] Further, in step B1, the weight percentage of the resin intermediate to the total weight of the resin mixture is 1-2%, 2-3%, 3-5%, 5-10%, 10-15%, 15-20%, 20-25%, 25-30%, 30-35% or 35-40%;

[0043] In step B2, the temperature of heating and curing is 10-60°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.

[0044] In step B3, the resin mixture after heating and curing is cooled to below 50° C. and stored, preferably, cooled to below 35° C. and stored.

[0045] The present invention further claims to protect the modified vinyl resin prepared by any one of the above methods.

[0046] Furthermore, the impact strength of the modified vinyl resin is increased by at least 20%, 30%, 40%, 50%, 60%, 70% or 80% relative to the vinyl resin; the tensile elongation at break of the modified vinyl resin is increased by at least 8%, 15%, 20%, 30%, 40%, 50%, 75% or 100% relative to the vinyl resin.

[0047] The present invention further provides a method for preparing a modified unsaturated resin using a resin intermediate prepared by any one of the above methods, comprising the following steps:

[0048] Step C1: uniformly mixing an unsaturated resin, a free radical initiator, a resin intermediate and an accelerator to obtain an unsaturated resin mixture;

[0049] Step C2: heat and cure the unsaturated resin mixture.

[0050] Step C3: Cooling the heated and cured unsaturated resin mixture to obtain a modified unsaturated resin.

[0051] Furthermore, the modified unsaturated resin can be used as a semi-cured material to participate in the preparation of derivatives such as thermosetting unsaturated composites.

[0052] In step C1, the resin intermediate accounts for 1-2%, 2-3%, 3-5%, 5-10%, 10-15%, 15-20%, 20-25%, 25-30%, 30-35% or 35-40% of the total weight of the unsaturated resin mixture;

[0053] In step C2, the temperature of heating and curing is 10-60°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.

[0054] In step C3, the unsaturated resin mixture after heating and curing is cooled to below 50°C.

[0055] The present invention further claims protection for the modified unsaturated resin prepared by any one of the above methods.

[0056] Furthermore, the impact strength of the modified unsaturated resin is increased by at least 20%, 30%, 40%, 50%, 60%, 70% or 80% relative to the unsaturated resin; the tensile elongation at break of the modified unsaturated resin is increased by at least 8%, 15%, 20%, 30%, 40%, 50%, 75% or 100% relative to the unsaturated resin.

[0057] The present invention provides a new toughening agent system in an innovative way, and uses the polyol product (i.e., resin intermediate) after the degradation of polyurethane waste to prepare thermosetting resin products and improve toughness. Therefore, it actually plays the role of a toughening agent and can be introduced into various thermosetting resin systems in a certain proportion by direct addition, which not only achieves the toughening effect, but also does not affect other properties of the cured thermosetting resin, effectively overcomes the pain points of the existing toughening agent system, and meets the needs of the industry. And the obtained modified thermosetting resin has similar application scenarios to conventional thermosetting resins, including but not limited to preparing various composite materials by infusion, pultrusion, winding, RTM, spraying, hand lay-up, prepreg, SMC / BMC and other process methods, such as blade parts, window frames, frames, various pultruded profiles, cable boxes, various parts of automobiles and ships, sports and leisure products, and various products and application scenarios such as adhesives and structural adhesives.

[0058] The present invention is based on the use of a degraded polyurethane product obtained from an initial polyurethane as a polyol product. The polyol product generally contains active hydrogen such as hydroxyl groups and amino groups. The polyol product can be used as a thermosetting resin toughening aid and added to a liquid thermosetting resin system before curing, thereby improving the toughness of the cured resin and not affecting other properties of the resin, such as heat resistance and mechanical strength. DETAILED DESCRIPTION

[0059] The detailed features and advantages of the present invention are described in detail in the specific implementation modes below, and the contents are sufficient to enable any person skilled in the art to understand the technical contents of the present invention and implement them accordingly. Moreover, according to the description and claims disclosed in this specification, those skilled in the art can easily understand the relevant objects and advantages of the present invention.

[0060] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below.

[0061] The raw materials used in this embodiment can be purchased on the market. Among them, liquid nitrile rubber DY-065 is purchased from Guangzhou Weilina Chemical Co., Ltd.; epoxy resin 127 and epoxy resin 128 are purchased from Nanya Chemical; cobalt water accelerator HL-88B and methyl ethyl ketone peroxide MEKP are purchased from Guangzhou Hongli Chemical; unsaturated resin uses 191 type o-phthalic polyester resin, and vinyl resin uses the most commonly used bisphenol A type 901 resin; various anhydrides and amine curing agents are purchased from Alibaba website; other reagents are purchased from Sinopharm or Alibaba website.

[0062] The present invention provides a method for preparing a resin intermediate used as a toughening aid, comprising the following steps:

[0063] Step A: The initial polyurethane is subjected 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 polymer to obtain a polyol product containing molecular fragments of the initial polymer; the polyol product can be added to a thermosetting resin system such as epoxy to participate in the curing process of the liquid resin as a toughening auxiliary component.

[0064] The detailed test process and results of Examples E1, E2 and E3 are given below for exemplary illustration:

[0065] Embodiment E1:

[0066] Step E1: 300 g of polyurethane waste (post-consumer refrigerator hard foam), 60 g of polyurethane waste (post-consumer polyurethane mattress foam material) and 400 g of diethylene glycol are mixed, 0.3 g of catalyst tetrabutyl titanate is added, 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 230° C. (210° C.-240° C.) to obtain a degradation reaction liquid.

[0067] Step E2: After the degradation reaction liquid is cooled to 120° C., it is filtered and separated to remove the undegraded solid residue, and the obtained filtrate is distilled under reduced pressure to remove excess ethylene glycol to obtain a polyol product E1. The hydroxyl value of the obtained polyol product E1 is 430 mgKOH / g, which is determined according to GB / T 12008.3-2009.

[0068] Embodiment E2:

[0069] Step E1: 200 g of polyurethane waste (post-consumer polyurethane soft foam material), 300 g of polyurethane waste (post-consumer container rigid foam) and 700 g of ethylene 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.

[0070] Step E2: The degradation reaction liquid is cooled to 50°C, and then filtered to separate and remove the undegraded solid residue. The obtained filtrate is subjected to reduced pressure distillation to remove excess ethylene glycol to obtain a polyol product E2, and the hydroxyl value of the obtained polyol product E2 is 260 mgKOH / g, which is determined according to GB / T 12008.3-2009.

[0071] Embodiment E3:

[0072] Step E1: 400 g of polyurethane waste (post-consumer polyurethane shoe outsole material), 200 g of propylene glycol and 100 g of DDL-1000 (hydroxyl value 110 mgKOH / g) 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 180° C. (170° C.-200° C.) to obtain a degradation reaction liquid.

[0073] Step E2: Cool the degradation reaction liquid to 80°C and filter to separate and remove the undegraded solid residue. The filtrate is distilled under reduced pressure to remove excess propylene glycol to obtain a polyol product E3. The hydroxyl value of the polyol product E3 is 150 mgKOH / g, as determined in GB / T 12008.3-2009.

[0074] As a further illustration of the toughening aid of the present invention, the active hydrogen in the polyol product is derived from groups such as hydroxyl and amino, and the hydroxyl value measured using GB / T 12008.3-2009 may actually correspond to the value of active hydrogen.

[0075] The present invention further provides a method for preparing a modified epoxy resin using a toughening aid, comprising the following steps:

[0076] Step 1: epoxy resin, anhydride curing agent, toughening agent, catalyst, DMP-30 and other raw materials are mixed evenly to obtain a mixture;

[0077] Step 2: pouring the mixture into a flat mold and then placing it in an oven for heating and curing, wherein the heating and curing is carried out under the following conditions: heating to 150°C at a rate of 80°C / 0.5 hour and maintaining at 150°C for 2 hours;

[0078] Step 3: Turn off the oven heating and allow the heated and cured mixture to cool naturally to room temperature (25° C.) to obtain a cured resin plate (modified epoxy resin).

[0079] The detailed test process and results of Examples 1 to 5 and Comparative Examples 1 to 3 are given below for exemplary description:

[0080] Example 1

[0081] 108 g of epoxy resin (Nan Ya 127), 100 g of methyltetrahydrophthalic anhydride (i.e., anhydride curing agent), 5 g of toughening agent E1 and 2 g of catalyst DMP-30 were mixed evenly to obtain a mixture; the mixture was cured according to steps 2 and 3 to obtain a cured resin plate (modified epoxy resin).

[0082] Example 2

[0083] 122 g of epoxy resin (Nan Ya 127), 100 g of phthalic anhydride (i.e., anhydride curing agent), 20 g of toughening agent E2 and 2 g of catalyst DMP-30 were mixed evenly to obtain a mixture; the mixture was cured according to steps 2 and 3 to obtain a cured resin plate (modified epoxy resin).

[0084] Example 3

[0085] 113 g of epoxy resin (Nan Ya 127), 100 g of methyltetrahydrophthalic anhydride (i.e., anhydride curing agent), 30 g of toughening agent E3 and 2 g of catalyst DMP-30 were mixed evenly to obtain a mixture; the mixture was cured according to steps 2 and 3 to obtain a cured resin plate (modified epoxy resin).

[0086] Example 4

[0087] 119 g of epoxy resin (Nan Ya 127), 100 g of methyltetrahydrophthalic anhydride (i.e., anhydride curing agent), 5 g of toughening agent E1, 30 g of toughening agent E3 and 2 g of catalyst DMP-30 were mixed evenly to obtain a mixture; the mixture was cured according to steps 2 and 3 to obtain a cured resin plate (modified epoxy resin).

[0088] Example 5

[0089] 115 g of epoxy resin (Nan Ya 127), 50 g of phthalic anhydride and 50 g of methyltetrahydrophthalic anhydride (i.e., anhydride curing agent), 25 g of toughening aid E2, 15 g of toughening aid E3 and 2 g of catalyst DMP-30 were mixed evenly to obtain a mixture; the mixture was cured according to steps 2 and 3 to obtain a cured resin plate (modified epoxy resin).

[0090] Comparative Example 1

[0091] 108 g of epoxy resin (Nan Ya 127), 100 g of methyltetrahydrophthalic anhydride (i.e., anhydride curing agent) and 2 g of catalyst DMP-30 were mixed evenly to obtain a mixture; the mixture was cured according to steps 2 and 3 to obtain a cured resin plate (cured epoxy resin).

[0092] Comparative Example 2

[0093] 122 g of epoxy resin (Nan Ya 127), 100 g of phthalic anhydride (i.e., anhydride curing agent) and 2 g of catalyst DMP-30 were mixed evenly to obtain a mixture; the mixture was cured according to steps 2 and 3 to obtain a cured resin plate (cured epoxy resin).

[0094] Comparative Example 3

[0095] 108 g of epoxy resin (Nan Ya 127), 100 g of methyltetrahydrophthalic anhydride (i.e., anhydride curing agent), 20 g of toughening agent (liquid nitrile rubber DY-065) and 2 g of catalyst DMP-30 were mixed evenly to obtain a mixture; the mixture was cured according to steps 2 and 3 to obtain a cured resin plate (cured epoxy resin).

[0096] The cured resin plates obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were tested according to the impact performance test standard ASTM D4812, and the DSC Tg was tested according to the glass transition temperature test standard ASTM D7426. The test results are shown in Tables 1 and 2.

[0097] Table 1: Properties of cured resin plates of Examples 1 to 5

[0098] sample Example 1 Example 2 Example 3 Example 4 Example 5 DSC Tg℃ 138 150 133 132 141 Impact strength (KJ / m2) 33 31 41 48 49

[0099] Table 2: Properties of Cured Resin Plates in Comparative Examples 1 to 3

[0100] sample Comparative Example 1 Comparative Example 2 Comparative Example 3 DSC Tg℃ 135 151 114 Impact strength (KJ / m2) 21 17 31

[0101] As can be seen from Table 1 and Table 2, the impact strength of the modified epoxy resin obtained by adding toughening agents in Examples 1 to 5 is greatly improved, indicating that its toughness has been significantly improved; but at the same time, the glass transition temperature Tg of Examples 1 to 5 and Comparative Examples 1 to 3 changes very little or even slightly increases, indicating that its heat resistance does not decrease due to the change of the toughening system of the present invention. Therefore, the modified epoxy resin obtained by the toughening agent of the present invention can effectively solve the disadvantage that the traditional toughening agent will reduce the physical properties of the toughened material.

[0102] The present invention further provides a method for obtaining a modified resin product by heating and curing with an amine curing agent. The detailed test process and results of Examples 6 to 7 and Comparative Examples 4 to 7 are given below for exemplary illustration:

[0103] Example 6

[0104] 100 g of epoxy resin (Nan Ya 128), 24 g of isophorone diamine (i.e., amine curing agent), 5 g of toughening aid E1, and 5 g of toughening aid E2 are mixed together to obtain a mixture; the mixture is first placed at room temperature for 0.5 hour, then placed at 60° C. for 2 hours, and then heated to 80° C. and maintained for 6 hours; the product is naturally cooled to room temperature and solidified to obtain a cured resin plate (modified epoxy resin).

[0105] Comparative Example 4

[0106] 100 g of epoxy resin (Nan Ya 128) and 24 g of isophorone diamine (i.e., an amine curing agent) were mixed together to obtain a mixture; the mixture was first placed at room temperature for 0.5 hour, then placed at 60° C. for 2 hours, and then heated to 80° C. and maintained for 6 hours; the product was naturally cooled to room temperature and solidified, and a cured resin plate (cured epoxy resin) was obtained after curing.

[0107] Comparative Example 5

[0108] 100 g of epoxy resin (Nan Ya 128), 24 g of isophorone diamine and 10 g of toughening agent (liquid nitrile rubber DY-065) were mixed together to obtain a mixture; the mixture was first placed at room temperature for 0.5 hour, then placed at 60° C. for 2 hours, and then heated to 80° C. and maintained for 6 hours; the product was naturally cooled to room temperature and solidified, and a cured resin plate (toughened and cured epoxy resin) was obtained after curing.

[0109] The cured resin plates obtained in Example 6 and Comparative Examples 4-5 were tested according to the impact performance test standard ASTM D4812, and the DSC Tg was tested according to the glass transition temperature test standard ASTM D7426. The test results are shown in Table 3.

[0110] Table 3: Properties of cured resin plates of Example 6 and Comparative Examples 4-5

[0111] sample Example 6 Comparative Example 4 Comparative Example 5 DSC Tg℃ 91 95 75 Impact strength (KJ / m2) 41 23 36

[0112] Comparative Example 6

[0113] 100 g of epoxy resin (Nan Ya 128) and 40 g of butanone were mixed and stirred into a uniform solution, and then 4 g of dicyandiamide and 0.1 g of 2-methylimidazole were added as curing agents, and stirred vigorously to obtain a uniform mixture; the mixture was poured into a horizontally placed flat mold, placed in an oven and heated to 140°C and maintained for 30 minutes; the product was naturally cooled to room temperature and solidified, and a cured resin plate (modified epoxy resin) was obtained after curing.

[0114] Comparative Example 7

[0115] 100 g of epoxy resin (Nan Ya 128), 8 g of toughening agent (liquid nitrile rubber DY-065) and 40 g of butanone were mixed and stirred into a uniform solution, and then 4 g of dicyandiamide and 0.1 g of 2-methylimidazole were added, and the mixture was vigorously stirred to obtain a uniform mixture; the mixture was poured into a horizontally placed flat plate mold, placed in an oven and heated to 140° C. and maintained for 30 minutes; the product was naturally cooled to room temperature and solidified, and a cured resin plate (modified epoxy resin) was obtained after solidification.

[0116] Example 7

[0117] 100 g of epoxy resin (Nan Ya 128), 5 g of E2, 7 g of E3, and 40 g of butanone were mixed and stirred into a uniform solution, and then 4 g of dicyandiamide and 0.1 g of 2-methylimidazole were added as curing agents, and stirred vigorously to obtain a uniform mixture; the mixture was poured into a horizontally placed flat plate mold, placed in an oven and heated to 140° C. and maintained for 30 minutes; the product was naturally cooled to room temperature, and a cured resin plate (modified epoxy resin) was obtained after curing.

[0118] The cured resin plates obtained in Example 7 and Comparative Examples 6-7 were tested according to the impact performance test standard ASTM D4812, and the DSC Tg was tested according to the glass transition temperature test standard ASTM D7426. The test results are shown in Table 4.

[0119] Table 4: Properties of cured resin plates of Example 7 and Comparative Examples 6-7

[0120] sample Example 7 Comparative Example 6 Comparative Example 7 DSC Tg℃ 130 135 117 Impact strength (KJ / m2) 39 20 34

[0121] Table 3 and Table 4 represent different epoxy curing systems. It can be seen from Table 3 and Table 4 that the impact strength of the modified epoxy resin obtained by adding toughening aids in Examples 6-7 is greatly improved, indicating that its toughness has been significantly improved; but at the same time, the glass transition temperature Tg of Examples 6-7 is very small compared with that of Comparative Examples 4 and 6, indicating that its heat resistance will not decrease due to the change of the toughening system of the present invention. In contrast, although the addition of conventional toughening agents to Comparative Examples 5 and 7 will appropriately improve toughness, the glass transition temperature Tg will be significantly reduced. Therefore, the modified epoxy resin obtained by the toughening aid of the present invention can effectively solve the disadvantage that traditional toughening agents will reduce other physical properties of the toughened material.

[0122] The polyol product of the present invention can also be added as a toughening agent component to other types of thermosetting resins, such as vinyl resins, unsaturated resins, phenolic resins and the like, to effectively improve the toughness of such thermosetting resins after curing without reducing other properties.

[0123] The present invention further provides a method for using such resin intermediates as toughening modifiers to prepare other types of thermosetting resins with improved toughness, such as vinyl resins, unsaturated resins, phenolic resins, etc., which can effectively improve the toughness of such thermosetting resins after curing without reducing other properties. The detailed test process and results of Examples 8 to 9 and Comparative Examples 8 to 9 are given below for exemplary explanation:

[0124] Comparative Example 8

[0125] 100 g of orthophthalic unsaturated resin 191, 1.5 g of MEKP and 1 g of cobalt water accelerator HL-88B were added and stirred to form a uniform solution, which was allowed to stand at room temperature for 16 hours and then placed in an oven at 80°C for 4 hours to obtain a cured resin plate.

[0126] Comparative Example 9

[0127] 100 g of vinyl resin 901 was added with 1.5 g of MEKP and 1 g of cobalt water accelerator HL-88B, and the mixture was stirred to form a uniform solution. The solution was allowed to stand at room temperature for 16 hours, and then placed in an oven at 80°C for 4 hours to obtain a cured resin plate.

[0128] Example 8

[0129] 100 g of orthophthalic unsaturated resin 191, 1.5 g of MEKP, 1 g of cobalt water accelerator HL-88B, and 8 g of E3 were added and stirred to form a uniform solution, which was allowed to stand at room temperature for 16 hours and then placed in an oven at 80°C for 4 hours to obtain a cured resin plate (modified unsaturated resin plate).

[0130] Example 9

[0131] Add 1.5 g MEKP, 1 g cobalt water accelerator HL-88B, 3 g E2 and 3 g E3 to 100 g vinyl resin 901, mix and stir to form a uniform solution, let stand at room temperature for 16 hours, and then place in an oven at 80°C for 4 hours to obtain a cured resin plate (modified vinyl resin plate).

[0132] The cured resin plates obtained in Examples 8 to 9 and Comparative Examples 8 to 9 were tested. The test results are shown in Table 5.

[0133] Table 5: Properties of Cured Resin Plates of Examples 8-9 and Comparative Examples 8-9

[0134] sample Test Standards Comparative Example 8 Comparative Example 9 Example 8 Example 9 DSC Tg℃ ASTM D7426 101 104 99 105 Impact strength (KJ / m2) ASTM D4812 15 19 26 32 Tensile strength MPa ASTM D638 70 81 73 82 Tensile modulus GPa ASTM D638 3.5 3.4 3.3 3.5 Tensile elongation at break % ASTM D638 2.3 4.9 5.1 5.3

[0135] As can be seen from Table 5, the toughening agent of the present invention can also effectively improve the toughness of thermosetting vinyl resins and unsaturated resins without reducing other properties. Preferably, the curing reaction temperature is 100-160°C; more preferably, the curing reaction temperature is 100-140°C.

[0136] The terms and expressions used herein are for descriptive purposes only, and the present invention should not be limited to these terms and expressions. The use of these terms and expressions does not mean to exclude any equivalent features of the illustrations and descriptions (or parts thereof), and it should be recognized that various modifications that may exist should also be included in the scope of the claims. Other modifications, variations and substitutions may also exist. Accordingly, the claims should be deemed to cover all such equivalents.

[0137] Likewise, it should be pointed out that although the present invention has been described with reference to the current specific embodiments, those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and various equivalent changes or substitutions may be made without departing from the spirit of the present invention. For example, it may also be used to toughen other thermosetting resins, including but not limited to phenolic resins, urea-formaldehyde resins, etc. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present invention, they will fall within the scope of the claims of the present invention.

Claims

1. A method for preparing a resin intermediate, characterized in that: The following steps are involved: Step A: subjecting the initial polymer to a degradation agent with an active group for degradation reaction, breaking at least a portion of the molecular chain of the initial polymer, and obtaining the resin intermediate containing the molecular chain fragments of the initial polymer with an active group; the initial polymer is an initial polyurethane; In the step A, the degradation reaction is an alcoholysis reaction, the degradation agent includes a polyol, and the polyol includes a diol and / or a high-functionality polyol.

2. The method for preparing a resin intermediate according to claim 1, characterized in that: The weight ratio of the initial polyurethane to the degradation agent is 1:0.1-0.4, 1:0.4-2, 1:2-5 or 1:5-15; The diols include low molecular weight C2-C6 diols; The low molecular weight C2-C6 diol includes one or more combinations of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, diethylene glycol, dipropylene glycol, ethylene glycol ketone, propylene glycol ketone or neopentyl glycol. The high-functionality polyol includes glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, sucrose polyol, sorbitol or polyether polyol. The temperature of the alcoholysis reaction 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 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.

3. A resin intermediate prepared according to any one of the preparation methods of claims 1 to 2.

4. The resin intermediate according to claim 3, characterized in that: The resin intermediate is used for manufacturing thermosetting resin products and for improving the toughness of the thermosetting resin products. The thermosetting resin products are epoxy resins, unsaturated resins or vinyl resins.

5. Use of the resin intermediate according to claim 3 in improving the toughness of a thermosetting resin product, wherein the thermosetting resin product is an epoxy resin, an unsaturated resin or a vinyl resin.

6. A method for preparing a modified epoxy resin using the resin intermediate according to claim 3, characterized in that: The following steps are involved: Step A1: uniformly mixing the epoxy resin, the curing agent and the resin intermediate to obtain an epoxy mixture; Step A2: heating and curing the epoxy mixture. Step A3: Cooling the epoxy mixture after heating and curing to obtain the modified epoxy resin.

7. The method for preparing a modified epoxy resin according to claim 6, characterized in that: In the step A1, the resin intermediate accounts for 1-2%, 2-3%, 3-5%, 5-10%, 10-15%, 15-20%, 20-25%, 25-30%, 30-35% or 35-40% of the total weight of the epoxy mixture; In the step A2, the temperature of the heating and curing is 10-60°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. In the step A3, the epoxy mixture after heating and curing is cooled to below 50°C.

8. The method for preparing a modified epoxy resin according to claim 6, characterized in that: The step A1 further comprises: The epoxy resin, the curing agent, the resin intermediate and the catalyst are uniformly mixed to obtain an epoxy mixture.

9. The method for preparing a modified epoxy resin according to claim 6, characterized in that: The curing agent is a compound that can react with the chain extending group, or a compound that can induce the chain extending group to react with each other. The reactive functional groups of the compound to react include one or a combination of free radical initiators, isocyanate groups, acid anhydrides, carboxyl groups, epoxy groups, amine groups, amide groups or aldehydes; The curing agent also includes an accelerator compatible with the free radical initiator; The accelerator includes metal salts, organic amines, including cobalt salts, copper salts, zinc salts or aniline accelerators.

10. The method for preparing a modified epoxy resin according to claim 9, characterized in that: The curing agent contains anhydride or amine reactive functional groups.

11. A modified epoxy resin prepared according to the method for preparing a modified epoxy resin according to claim 6, wherein the impact strength of the modified epoxy resin is increased by at least 20%, 30%, 40%, 50%, 60%, 70% or 80% relative to that of the epoxy resin; and the tensile elongation at break of the modified epoxy resin is increased by at least 8%, 15%, 20%, 30%, 40%, 50%, 75% or 100% relative to that of the epoxy resin.

12. A method for preparing a modified vinyl resin using the resin intermediate according to claim 3, characterized in that: The following steps are involved: Step B1: uniformly mixing a vinyl resin, a free radical initiator, the resin intermediate and an accelerator to obtain a resin mixture; Step B2: heating and curing the resin mixture. Step B3: Cooling the resin mixture after heating and curing to obtain the modified vinyl resin.

13. The method for preparing a modified vinyl resin according to claim 12, characterized in that: In the step B1, the resin intermediate accounts for 1-2%, 2-3%, 3-5%, 5-10%, 10-15%, 15-20%, 20-25%, 25-30%, 30-35% or 35-40% of the total weight of the resin mixture; In the step B2, the heating and curing temperature is 10-60°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. In the step B3, the resin mixture after heating and curing is cooled to below 50°C.

14. A modified vinyl resin obtained according to the method for preparing a modified vinyl resin according to claim 12, wherein the impact strength of the modified vinyl resin is increased by at least 20%, 30%, 40%, 50%, 60%, 70% or 80% relative to that of the vinyl resin; and the tensile elongation at break of the modified vinyl resin is increased by at least 8%, 15%, 20%, 30%, 40%, 50%, 75% or 100% relative to that of the vinyl resin.

15. A method for preparing a modified unsaturated resin using the resin intermediate according to claim 3, characterized in that: The following steps are involved: Step C1: uniformly mixing an unsaturated resin, a free radical initiator, the resin intermediate and an accelerator to obtain an unsaturated resin mixture; Step C2: heating and curing the unsaturated resin mixture, Step C3: Cooling the unsaturated resin mixture after heating and curing to obtain the modified unsaturated resin.

16. The method for preparing a modified unsaturated resin according to claim 15, characterized in that: In the step C1, the resin intermediate accounts for 1-2%, 2-3%, 3-5%, 5-10%, 10-15%, 15-20%, 20-25%, 25-30%, 30-35% or 35-40% of the total weight of the unsaturated resin mixture; In the step C2, the temperature of the heating and curing is 10-60°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. In the step C3, the unsaturated resin mixture after heating and curing is cooled to below 50°C.

17. A modified unsaturated resin obtained by the method for preparing a modified unsaturated resin according to claim 15, wherein the impact strength of the modified unsaturated resin is increased by at least 20%, 30%, 40%, 50%, 60%, 70% or 80% relative to that of the unsaturated resin; and the tensile elongation at break of the modified unsaturated resin is increased by at least 8%, 15%, 20%, 30%, 40%, 50%, 75% or 100% relative to that of the unsaturated resin.