Method for preparing hydroxyl-terminated macromolecular polyester polyol without metal catalyst and polyester polyol

Abstract

The invention discloses a method for preparing hydroxyl-terminated macromolecular polyester polyol without a metal catalyst and polyester polyol, and the method comprises the following steps: step 1, esterification stage: carrying out esterification reaction on a dihydric alcohol monomer and an excessive molar ratio of cyclization dicarboxylic acid or anhydride as raw materials in the absence of a catalyst to obtain a carboxyl-terminated prepolymer; step 2, polyester polycondensation stage: carrying out reduced pressure distillation on the product in the step 1, and reacting at the temperature not lower than the boiling point temperature of anhydride to obtain a carboxyl-terminated macromolecular polyester product; step 3, carboxyl substitution stage: adding a solvent and thionyl chloride in a preset proportion into the product in the step 2, and reacting at preset temperature for preset time to obtain a diacyl chloride polymer; and step 4, a hydroxyl end-capping stage: adding excessive diol monomers and a proper amount of a non-metal catalyst into the product obtained in the step 3, reacting at a preset temperature for a preset time, and distilling out the excessive diol monomers and small molecular byproducts through reduced pressure distillation to obtain the hydroxyl-terminated high-molecular polyester polyol. The invention widens the way of synthesizing high-molecular polyester polyol by condensation polymerization.

Description

Technical Field

[0001] The invention relates to the technical field of polymer material preparation, and in particular to a method for preparing hydroxyl-terminated polymer polyester polyol without a metal catalyst and the polyester polyol. Background Art

[0002] Polyester polyols generally refer to a class of compounds with repeated ester groups in the molecular chain and hydroxyl end-capping. Depending on whether they contain aromatic rings, they can be divided into aromatic polyester polyols and aliphatic polyester polyols. Polyester polyols are usually synthesized by esterification-transesterification condensation of polycarboxylic acids (anhydrides or esters) and polyols (including hydroxy acids), or by ring-opening synthesis of lactones and polyols.

[0003] Polyester polyols for polyurethane materials generally refer to special polyester polyols with a molecular weight of 5000-30000g / mol and are easily soluble in organic solvents such as ethyl acetate. They are generally used as the main agent of two-component polyurethane adhesives for bonding composite films and aluminum-plastic laminates. They can also be used for baking polyurethane coatings, metal protective coatings, etc. Compared with traditional polyester polyols, polyester polyols have the advantages of high toughness, high strength, high weather resistance, etc., and therefore have higher added value.

[0004] At present, the technology of high molecular weight polyester polyols for adhesives is mainly provided by large multinational companies in developed countries such as Japan, Germany, and the United States. For example, Japan's Toyobo Group has a relatively comprehensive product range. The VYLON series of non-crystalline copolyesters covers high, medium, and low glass transition temperatures, and has excellent bonding properties to substrates such as PET and metal, and is widely used in functionalized solvent-based polyurethane adhesives.

[0005] In the traditional synthesis process of high molecular weight polyester polyols, a large amount of metal catalysts are generally used to reduce the activation energy and promote the reaction. Heavy metal catalysts such as organic titanium, organic antimony, organic cobalt, and organic lead are generally used. These heavy metal catalysts will bring hazards such as environmental pollution and long-term chronic toxicity to the human body. The addition of a large amount of catalysts will also increase the risk of degradation of the synthesized high molecular weight polyester resin.

[0006] At present, Chinese patents CN110790906A, CN111978528A and CN112831033A have published a series of catalyst-free methods for synthesizing carboxyl-terminated polymer polyester polyols. Compared with traditional methods, heavy metal catalysts with physiological toxicity to the human body are removed, and they can be better applied in the fields of biomedicine. However, since the prepared polymer polyester resin is carboxyl-terminated and does not have the reactivity with isocyanate groups, it is difficult to be applied in the field of polyurethane materials.

[0007] Therefore, how to develop a method for preparing hydroxyl-terminated high molecular weight polyester polyols without metal catalyst is a problem that needs to be solved.

[0008] In view of this, the present invention is proposed. Summary of the invention

[0009] The purpose of the present invention is to provide a method for preparing a terminal hydroxyl polymer polyester polyol without a metal catalyst and a polyester polyol, which can produce a polymer polyester polyol that has reaction activity with isocyanate groups and meets the requirements of polyurethane adhesive application, thereby solving the above-mentioned technical problems existing in the prior art.

[0010] The objective of the present invention is achieved through the following technical solutions:

[0011] A method for preparing hydroxyl-terminated high molecular weight polyester polyol without a metal catalyst comprises:

[0012] Step 1, esterification stage: using a diol monomer and an excess molar ratio of component one as raw materials, wherein component one is a cyclic dicarboxylic acid or anhydride, an esterification reaction is carried out in a reactor at a predetermined reaction temperature and reaction time in the absence of a catalyst to obtain a carboxyl-terminated prepolymer;

[0013] Step 2, polyester polycondensation stage: performing reduced pressure distillation on the carboxyl-terminated prepolymer obtained in step 1 for a predetermined time in a reactor at a temperature not lower than the boiling point of the anhydride formed by the cyclic dicarboxylic acid to obtain a carboxyl-terminated high molecular weight polyester product;

[0014] Step 3, carboxyl substitution stage: adding a predetermined ratio of solvent and a predetermined ratio of thionyl chloride to the carboxyl-terminated high molecular weight polyester product obtained in step 2, and reacting at a predetermined reaction temperature and time to obtain a diacyl chloride polymer;

[0015] Step 4, hydroxyl-terminated stage: add an excess of diol monomer and an appropriate amount of non-metallic catalyst to the diacyl chloride polymer obtained in step 3 to react at a predetermined reaction temperature and time, and then distill off the excess diol monomer and small molecular by-products under reduced pressure to obtain a hydroxyl-terminated high molecular weight polyester polyol.

[0016] Further, in step 1 of the above method, the diol monomer is any one or more of ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, dipropylene glycol, 2-methyl-1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol;

[0017] The cyclic dicarboxylic acid is a dicarboxylic acid that is easy to form a five-membered cyclic anhydride or a dicarboxylic acid that is easy to form a six-membered cyclic anhydride;

[0018] The acid anhydride is any one or more of succinic anhydride, 2-methylsuccinic anhydride, 2-phenylsuccinic anhydride, 2-benzylsuccinic anhydride, 2,2-dimethylsuccinic anhydride, 2,3-dimethylsuccinic anhydride, 2,3-diphenylsuccinic anhydride, 1,2-cyclosuccinic anhydride, 2,2,3,3-tetramethylsuccinic anhydride, maleic anhydride, glutaric anhydride, 2-ketoglutaric anhydride, 1,3-acetone dicarboxylic anhydride, 2-methylglutaric anhydride, 3-methylglutaric anhydride, 3-phenylglutaric anhydride, 2,2-dimethylglutaric anhydride, 3,3-dimethylglutaric anhydride, 3-ethyl-3-methylglutaric anhydride, 3,3-tetramethyleneglutaric anhydride, phthalic anhydride, 1,2,5,6-tetrahydrophthalic anhydride, and 1,2-cyclohexanedicarboxylic anhydride.

[0019] Furthermore, in the above method, the cyclic dicarboxylic acid is any one or more of succinic acid, 2-methylsuccinic acid, 2-phenylsuccinic acid, 2-benzylsuccinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylsuccinic acid, 2,3-diphenylsuccinic acid, 1,2-cyclobutanedicarboxylic acid, 2,2,3,3-tetramethylsuccinic acid, maleic acid, glutaric acid, 2-ketoglutaric acid, 1,3-acetonedicarboxylic acid, 2-methylglutaric acid, 3-methylglutaric acid, 3-phenylglutaric acid, 2,2-dimethylglutaric acid, 3,3-dimethylglutaric acid, 3-ethyl-3-methylglutaric acid, 3,3-tetramethyleneglutaric acid, phthalic acid, 1,2,5,6-tetrahydrophthalic acid, and 1,2-cyclohexanedicarboxylic acid.

[0020] Furthermore, in step 1 of the above method, the molar ratio of the excess molar ratio of component 1 to the diol monomer is 1.2 to 2.0;

[0021] The predetermined reaction temperature in step 1 is 100-300° C., and the reaction time is 6-48 hours.

[0022] Furthermore, in step 2 of the above method, the temperature not lower than the boiling point of the anhydride formed by the cyclic dicarboxylic acid is 100 to 300°C;

[0023] The reaction pressure of the reduced pressure distillation is ≤300Pa, and the reaction time is 4 to 48 hours.

[0024] Furthermore, in step 3 of the above method, the predetermined ratio of solvent added is: the mass ratio of the carboxyl-terminated high molecular weight polyester product in the reactor to the solvent is 100:1000 to 100:10;

[0025] The solvent is any one or more of ethyl acetate, butyl acetate, acetone, butanone, tetrahydrofuran, dichloromethane, chloroform, carbon tetrachloride, N,N-dimethylamide, and tetrachloroethane;

[0026] The predetermined ratio of thionyl chloride is added: the mass ratio of the carboxyl-terminated high molecular weight polyester product in the reactor to thionyl chloride is 100:1 to 100:50;

[0027] The predetermined reaction temperature is 50-90° C.; the reaction time is 2-6 hours.

[0028] Furthermore, in step 4 of the above method, the excess diol monomer is: the amount of diol monomer used is greater than the amount required to react with the high molecular weight terminal acyl chloride group of the diacid chloride polymer and the remaining thionyl chloride in step 2;

[0029] The diol monomer is any one or more of ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, dipropylene glycol, 2-methyl-1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol;

[0030] The mass ratio of the diacid chloride polymer to the diol monomer in the reactor is 100:10 to 100:50;

[0031] The catalyst is any one or more of triethylamine, tetramethylbutylene diamine, triethylene diamine, tetramethylbutylene diamine, N-ethylmorpholine, and N,N'-diethylpiperazine;

[0032] The catalyst dosage is 0.01-1% of the total solid weight content.

[0033] The predetermined reaction temperature is -50 to 80°C, and the reaction time is 2 to 6 hours;

[0034] The reduced pressure distillation temperature is 100-150° C., the pressure is ≤300 Pa, and the duration is 2-6 hours.

[0035] A hydroxyl-terminated high molecular polyester polyol is prepared by the method for preparing hydroxyl-terminated high molecular polyester polyol using a metal-free catalyst according to the present invention. The hydroxyl value of the hydroxyl-terminated high molecular polyester polyol is 4-20 mgKOH / g and the acid value is ≤0.5 mgKOH / g.

[0036] Compared with the prior art, the method for preparing hydroxyl-terminated high molecular weight polyester polyol using a metal-free catalyst and the polyester polyol provided by the present invention have the following beneficial effects:

[0037] By first preparing a carboxyl-terminated polymer polyester, and then modifying the carboxyl-terminated polymer polyester to terminate the diol monomer, the preparation and synthesis of hydroxyl-terminated polymer polyester polyols is achieved, providing a new idea for synthesizing polymer polyester polyols for polyurethane materials, and broadening the method of synthesizing polymer polyester polyols by condensation polymerization; since there is no metal catalyst, the reverse reaction of polyester decomposition catalyzed by metal catalysts can be avoided or weakened, which is helpful for the stability of subsequent polyurethane products. This method is more compatible with the current traditional synthesis of polyester polyols, and is more convenient for subsequent pilot and industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The reaction mechanism diagram of the method provided in the embodiment of the present invention. DETAILED DESCRIPTION

[0039] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in combination with the specific content of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, which does not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present invention.

[0040] First, the terms that may be used in this article are explained as follows:

[0041] The term “and / or” means that either or both of them can be realized at the same time. For example, X and / or Y means both “X” or “Y” and “X and Y”.

[0042] The terms "include", "comprises", "contains", "has" or other descriptions with similar semantics should be interpreted as non-exclusive inclusion. For example, including certain technical feature elements (such as raw materials, components, ingredients, carriers, dosage forms, materials, dimensions, parts, components, mechanisms, devices, steps, procedures, methods, reaction conditions, processing conditions, parameters, algorithms, signals, data, products or products, etc.) should be interpreted as including not only certain technical feature elements explicitly listed, but also other technical feature elements known in the art that are not explicitly listed.

[0043] The term "consisting of..." means excluding any technical feature elements not explicitly listed. If this term is used in a claim, it will make the claim closed, so that it does not contain technical feature elements other than the technical feature elements explicitly listed, except for the conventional impurities related to them. If this term only appears in a clause of a claim, it only limits the elements explicitly listed in the clause, and the elements recorded in other clauses are not excluded from the overall claim.

[0044] The term "parts by mass" refers to the mass ratio relationship between multiple components. For example, if it is described that component X is x parts by mass and component Y is y parts by mass, then the mass ratio of component X to component Y is x:y. 1 part by mass can represent any mass, for example, 1 part by mass can be represented as 1 kg or 3.1415926 kg. The sum of the parts by mass of all components is not necessarily 100 parts, but can be greater than 100 parts, less than 100 parts or equal to 100 parts. Unless otherwise specified, the parts, proportions and percentages described herein are all measured by mass.

[0045] When concentration, temperature, pressure, size or other parameters are expressed in the form of a numerical range, the numerical range should be understood to specifically disclose all ranges formed by the pairing of any upper limit, lower limit, and preferred value in the numerical range, regardless of whether the range is explicitly stated; for example, if a numerical range of "2 to 8" is stated, the numerical range should be interpreted as including ranges such as "2 to 7", "2 to 6", "5 to 7", "3 to 4 and 6 to 7", "3 to 5 and 7", "2 and 5 to 7", etc. Unless otherwise specified, the numerical ranges stated herein include both their end values ​​and all integers and fractions within the numerical range.

[0046] The scheme provided by the present invention is described in detail below. The contents not described in detail in the embodiments of the present invention belong to the prior art known to professionals in the field. If the specific conditions are not specified in the embodiments of the present invention, they are carried out according to the conventional conditions in the field or the conditions recommended by the manufacturer. If the manufacturers are not specified in the reagents or instruments used in the embodiments of the present invention, they are all conventional products that can be purchased commercially.

[0047] like Figure 1 As shown in the reaction mechanism, the embodiment of the present invention provides a method for preparing a hydroxy-terminated polymer polyester polyol without a metal catalyst, which is a method for synthesizing a polyester polyol that can be used for polyurethane materials and can accurately control the molecular weight and hydroxyl value, comprising:

[0048] Step 1, esterification stage: using a diol monomer and an excess molar ratio of component one as raw materials, component one adopts a cyclic dicarboxylic acid or a corresponding acid anhydride, and performing an esterification reaction at a predetermined reaction temperature and reaction time in the absence of a catalyst to obtain a carboxyl-terminated prepolymer;

[0049] Step 2, polyester polycondensation stage: subjecting the carboxyl-terminated prepolymer obtained in step 1 to reduced pressure distillation at a temperature not lower than the boiling point of the anhydride formed by the cyclic dicarboxylic acid for a certain period of time to obtain a carboxyl-terminated high molecular weight polyester product;

[0050] Step 3, carboxyl substitution stage: adding a predetermined ratio of solvent and a predetermined ratio of thionyl chloride to the carboxyl-terminated high molecular weight polyester product obtained in step 2, and reacting at a predetermined reaction temperature and time to obtain a diacyl chloride polymer;

[0051] Step 4, hydroxyl-terminated stage: add an excess of diol monomer and an appropriate amount of non-metallic catalyst to the diacyl chloride polymer obtained in step 3 to react at a predetermined reaction temperature and time, and then distill off the excess diol monomer and small molecular by-products under reduced pressure to obtain a hydroxyl-terminated high molecular weight polyester polyol product.

[0052] In a preferred embodiment, the diol monomer in step 1 is any one or more of ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, dipropylene glycol, 2-methyl-1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol;

[0053] The cyclic dicarboxylic acid refers to a dicarboxylic acid that is easy to form a five-membered or six-membered cyclic anhydride, and can be selected from any one or more of succinic acid, 2-methylsuccinic acid, 2-phenylsuccinic acid, 2-benzylsuccinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylsuccinic acid, 2,3-diphenylsuccinic acid, 1,2-cyclobutanedicarboxylic acid, 2,2,3,3-tetramethylsuccinic acid, maleic acid, glutaric acid, 2-ketoglutaric acid, 1,3-acetonedicarboxylic acid, 2-methylglutaric acid, 3-methylglutaric acid, 3-phenylglutaric acid, 2,2-dimethylglutaric acid, 3,3-dimethylglutaric acid, 3-ethyl-3-methylglutaric acid, 3,3-tetramethyleneglutaric acid, phthalic acid, 1,2,5,6-tetrahydrophthalic acid, and 1,2-cyclohexanedicarboxylic acid;

[0054] The acid anhydride is selected from any one or more of succinic anhydride, 2-methylsuccinic anhydride, 2-phenylsuccinic anhydride, 2-benzylsuccinic anhydride, 2,2-dimethylsuccinic anhydride, 2,3-dimethylsuccinic anhydride, 2,3-diphenylsuccinic anhydride, 1,2-cyclosuccinic anhydride, 2,2,3,3-tetramethylsuccinic anhydride, maleic anhydride, glutaric anhydride, 2-ketoglutaric anhydride, 1,3-acetone dicarboxylic anhydride, 2-methylglutaric anhydride, 3-methylglutaric anhydride, 3-phenylglutaric anhydride, 2,2-dimethylglutaric anhydride, 3,3-dimethylglutaric anhydride, 3-ethyl-3-methylglutaric anhydride, 3,3-tetramethyleneglutaric anhydride, phthalic anhydride, 1,2,5,6-tetrahydrophthalic anhydride, and 1,2-cyclohexanedicarboxylic anhydride.

[0055] In a preferred embodiment, the excess molar ratio of the cyclic dicarboxylic acid or anhydride in step 1 means that the molar ratio of the cyclic dicarboxylic acid or anhydride diol monomer is greater than 1, preferably 1.2 to 2.0;

[0056] The predetermined reaction temperature is 100-300° C., preferably 150-250° C.; the reaction time is 6-48 hours, preferably 8-24 hours.

[0057] In a preferred embodiment, in the polyester polycondensation stage in step 2, the product in step 1 is subjected to reduced pressure distillation at a temperature not lower than the boiling point of the anhydride formed by the cyclic dicarboxylic acid, and the anhydride is formed by "biting back" at the end of the molecular chain and evaporated, so that the system spontaneously approaches the condition of an equimolar ratio of alkyd and acid, thereby obtaining a high molecular weight aliphatic polyester or copolyester.

[0058] In step 2, the reaction pressure of the reduced pressure distillation is ≤300 Pa, the predetermined reaction temperature is 100-300° C., preferably 150-250° C.; the reaction time is 4-48 hours, preferably 6-24 hours.

[0059] In a preferred embodiment, in step 3,

[0060] The predetermined ratio of solvent added is that the mass ratio of the carboxyl-terminated high molecular weight polyester product to the solvent in the reactor is 100:1000 to 100:10, preferably 100:100 to 100:10;

[0061] The solvent type is one or more of ethyl acetate, butyl acetate, acetone, butanone, tetrahydrofuran, dichloromethane, chloroform, carbon tetrachloride, N,N-dimethylamide, and tetrachloroethane.

[0062] The predetermined ratio of thionyl chloride added is: the mass ratio of the carboxyl-terminated high molecular polyester product in the reactor to thionyl chloride is 100:1 to 100:50, preferably 100:5 to 100:20.

[0063] In step 3, the predetermined reaction temperature is 50 to 90° C.; and the reaction time is 2 to 6 hours.

[0064] In a preferred embodiment, in step 2, the excess diol monomer means that the amount of diol monomer is greater than the amount required to react with the high molecular weight terminal acyl chloride groups of the diacid chloride polymer and the remaining thionyl chloride in step 2.

[0065] The diol monomer used is any one or more of ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, dipropylene glycol, 2-methyl-1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol;

[0066] The mass ratio of the diacid chloride polymer to the diol monomer in the reactor is 100:10 to 100:50;

[0067] The catalyst is any one or more of triethylamine, tetramethylbutylene diamine, triethylene diamine, tetramethylbutylene diamine, N-ethylmorpholine, and N,N'-diethylpiperazine.

[0068] The amount of the catalyst is 0.01-1% of the total solid mass content, preferably 0.1-0.5%;

[0069] The predetermined reaction temperature is -50 to 80°C, preferably -20 to 50°C; the reaction time is 2 to 6 hours;

[0070] The reduced pressure distillation temperature is 100-150° C., the pressure is ≤300 Pa, and the duration is 2-6 hours.

[0071] The present invention also provides a terminal hydroxyl high molecular polyester polyol prepared by using the above raw materials and method in the absence of a metal catalyst.

[0072] In summary, compared with the prior art, the method of the present invention has at least the following beneficial effects:

[0073] (1) The preparation and synthesis of terminal hydroxyl polymer polyester polyols is achieved by first preparing terminal carboxyl polymer polyesters and then modifying the terminal carboxyl polymer polyesters to terminate diol monomers, providing a new idea for synthesizing polymer polyester polyols for polyurethane materials and broadening the method for synthesizing polymer polyester polyols by condensation polymerization;

[0074] (2) Since the metal-free catalyst can avoid or weaken the reverse reaction of polyester decomposition catalyzed by the metal catalyst, it is helpful for the stability of subsequent polyurethane products.

[0075] (3) This method is more compatible with the current traditional equipment for synthesizing polyester polyols, and is more convenient for subsequent pilot production and industrialization.

[0076] In order to more clearly demonstrate the technical solution and technical effects provided by the present invention, the solution provided by the embodiment of the present invention is described in detail with specific embodiments below.

[0077] The raw materials used in the examples are all conventional commercially available raw materials.

[0078] Test method:

[0079] Acid value titration of polyester polyols, according to HG / T 2708-95;

[0080] Hydroxyl value titration of polyester polyols is based on HG / T 2709-95.

[0081] Example 1

[0082] This embodiment provides a method for preparing hydroxyl-terminated high molecular weight polyester polyol without a metal catalyst, comprising the following steps:

[0083] Step 1, add succinic acid (141.7 g, 1.2 mol), phthalic anhydride (177.7 g, 1.2 mol), ethylene glycol (62.1 g, 1.0 mol), diethylene glycol (106.1 g, 1.0 mol) into a reactor with rotation torque and stirring power, the molar ratio of diacid to diol is 1.2:1, and gradually increase the temperature from 150°C at the beginning of esterification to 250°C, and collect the theoretical fraction to obtain the terminal carboxyl esterified product.

[0084] Step 2, maintaining the temperature at 240° C. for vacuum distillation to ensure that the system pressure is ≤300 Pa, polycondensing for about 10 hours, reaching a predetermined current A, completing the polyester polycondensation stage, and obtaining a carboxyl-terminated high molecular weight polyester.

[0085] Step 3, cooling the system to below 100°C, adding 250g of ethyl acetate, stirring and mixing evenly, keeping the temperature at 80°C, adding 100g of thionyl chloride into the system, keeping the temperature at 80°C for 6h, completing the carboxyl substitution stage, and obtaining a mixture of a high molecular weight polyester terminated with acyl chloride and excess thionyl chloride and ethyl acetate.

[0086] Step 4, add 240g ethylene glycol and 3g triethylamine into the system, react at 50°C for 6h, then heat to 120°C, distill out the excess solvent first, then distill out the excess ethylene glycol and small molecular by-products by reduced pressure distillation, and finally obtain terminal hydroxyl polymer polyester polyol.

[0087] Example 2

[0088] This embodiment provides a method for preparing hydroxyl-terminated high molecular weight polyester polyol without a metal catalyst, comprising the following steps:

[0089] Step 1, add succinic acid (177.1g, 1.5mol), phthalic anhydride (222.2g, 1.5mol), ethylene glycol (62.1g, 1.0mol), diethylene glycol (106.1g, 1.0mol) into a reactor with rotation torque and stirring power, the molar ratio of diacid to diol is 1.5:1, and gradually increase the temperature from 150°C at the beginning of esterification to 250°C, and collect the theoretical fraction to obtain the terminal carboxyl esterified product.

[0090] Steps 2 to 4 are the same as those in Example 1, please refer to Example 1.

[0091] Example 3

[0092] This embodiment provides a method for preparing hydroxyl-terminated high molecular weight polyester polyol without a metal catalyst, comprising the following steps:

[0093] Step 1 is the same as step 1 of Example 2, please refer to Example 2;

[0094] Step 2, maintaining the temperature at 240° C. for vacuum distillation to ensure that the system pressure is ≤300 Pa, polycondensing for about 20 hours, reaching a predetermined current B, completing the polyester polycondensation stage, and obtaining a carboxyl-terminated high molecular polyester;

[0095] Step 3, cooling the system to below 100° C., adding 500 g of ethyl acetate, stirring and mixing, and keeping the temperature at 80° C., adding 30 g of thionyl chloride to the system, and keeping the temperature at 80° C. for 4 hours to complete the carboxyl substitution stage, and obtaining a mixture of a high molecular weight polyester terminated with acyl chloride and excess thionyl chloride and ethyl acetate;

[0096] Step 4, add 60g ethylene glycol and 1g triethylamine into the system, react at 20°C for 6h, then heat to 150°C, distill out the excess solvent first, then distill under reduced pressure to distill out the excess ethylene glycol and small molecular by-products, and finally obtain terminal hydroxyl polymer polyester polyol.

[0097] Example 4

[0098] This embodiment provides a method for preparing hydroxyl-terminated high molecular weight polyester polyol without a metal catalyst, comprising the following steps:

[0099] Steps 1 to 3 are the same as those in Example 3, please refer to Example 3;

[0100] Step 4, add 60g 1,4-butanediol and 1g triethylamine into the system, react at 20°C for 6h, then heat to 150°C, distill out the excess solvent first, then distill out the excess 1,4-butanediol and small molecular by-products by reduced pressure distillation, and finally obtain terminal hydroxyl polymer polyester polyol.

[0101] Example 5

[0102] This embodiment provides a method for preparing hydroxyl-terminated high molecular weight polyester polyol without a metal catalyst, comprising the following steps:

[0103] Step 1, add succinic anhydride (120.1g, 1.2mol), glutaric acid (158.6g, 1.2mol), neopentyl glycol (104.2g, 1.0mol), 1,6-hexanediol (118.2g, 1.0mol) into a reactor with rotation torque and stirring power, the molar ratio of diacid to diol is 1.2:1, and gradually increase the temperature from 150°C at the beginning of esterification to 250°C, and collect the theoretical fraction to obtain the terminal carboxyl esterified product.

[0104] Steps 2 to 4 are the same as those in Example 1, please refer to Example 1.

[0105] Example 6

[0106] This embodiment provides a method for preparing hydroxyl-terminated high molecular weight polyester polyol without a metal catalyst, comprising the following steps:

[0107] Step 1 is the same as step 1 of Example 5, please refer to Example 5;

[0108] Steps 2 to 4 are the same as those in Example 3, please refer to Example 3.

[0109] Comparative Example 1

[0110] This comparative example is a hydroxy-terminated high molecular weight polyester polyol prepared by a conventional condensation polymerization method and having the same main structure and similar molecular weight as Example 1.

[0111] Specifically, succinic acid (141.7 g, 1.2 mol), phthalic anhydride (177.7 g, 1.2 mol), ethylene glycol (89.4 g, 1.44 mol), and diethylene glycol (152.8 g, 1.44 mol) were added to a reactor with rotation torque and stirring power, and the ratio of diacid to diol was set to 1:2.2. The temperature was gradually increased from 150°C at the beginning of esterification to 250°C, and the terminal hydroxyl ester was obtained after the theoretical fraction was collected.

[0112] After the esterification was completed, the temperature was maintained at 240°C, and about 400 ppm of tetrabutyl titanate was added to the system for polyester polycondensation. The final polycondensation took about 4 hours to reach the predetermined current A, and then the reaction was stopped.

[0113] Comparative Example 2

[0114] This comparative example is a hydroxy-terminated high molecular weight polyester polyol having the same main structure and similar molecular weight as Example 3, which is prepared by a traditional condensation polymerization method.

[0115] Succinic acid (141.7 g, 1.2 mol), phthalic anhydride (177.7 g, 1.2 mol), ethylene glycol (89.4 g, 1.44 mol), and diethylene glycol (152.8 g, 1.44 mol) were added to a reactor with rotation torque and stirring power. The ratio of diacid to diol was set to 1:2.2, and the temperature was gradually increased from 150°C at the beginning of esterification to 250°C, and the terminal hydroxyl ester was obtained after the theoretical fraction was collected.

[0116] After the esterification was completed, the temperature was maintained at 240°C, and about 400 ppm of tetrabutyl titanate was added to the system for polyester polycondensation. The final polycondensation took about 6 hours to reach the predetermined current B, and the reaction was stopped.

[0117] Table 1 is the titration results of hydroxyl value and acid value of Examples 1 to 6 and Comparative Examples 1 to 2

[0118] Hydroxyl value (HV) / (mgKOH / g) Acid value (AV) / (mgKOH / g) Example 1 12.1 0.1 Example 2 12.5 0.1 Example 3 6.6 0.1 Example 4 6.8 0.1 Example 5 8.6 0.1 Example 6 5.3 0.1 Comparative Example 1 12.3 0.2 Comparative Example 2 6.5 0.3

[0119] The acid value and hydroxyl value of the obtained terminal hydroxyl polymer polyester polyol are titrated according to the corresponding industry standards. The method of the present invention can successfully synthesize a polymer polyester product similar to that of the traditional method.

[0120] The terminal hydroxyl high molecular polyester polyol prepared by the invention can be used in polyurethane materials such as two-component polyurethane adhesives, polyurethane coatings and metal protective coatings.

[0121] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims. The information disclosed in the background technology section of this article is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or in any form that the information constitutes prior art known to those skilled in the art.

Claims

1. A method for preparing hydroxyl-terminated polymer polyester polyols without metal catalyst, characterized in that: include: Step 1, esterification stage: using a diol monomer and an excess molar ratio of component one as raw materials, wherein component one is a cyclic dicarboxylic acid or anhydride, an esterification reaction is carried out in a reactor at a predetermined reaction temperature and reaction time in the absence of a catalyst to obtain a carboxyl-terminated prepolymer; Step 2, polyester polycondensation stage: performing reduced pressure distillation on the carboxyl-terminated prepolymer obtained in step 1 for a predetermined time in a reactor at a temperature not lower than the boiling point of the anhydride formed by the cyclic dicarboxylic acid to obtain a carboxyl-terminated high molecular weight polyester product; Step 3, carboxyl substitution stage: adding a predetermined ratio of solvent and a predetermined ratio of thionyl chloride to the carboxyl-terminated high molecular weight polyester product obtained in step 2, and reacting at a predetermined reaction temperature and time to obtain a diacyl chloride polymer; Step 4, hydroxyl-terminated stage: add an excess of diol monomer and an appropriate amount of non-metallic catalyst to the diacyl chloride polymer obtained in step 3 to react at a predetermined reaction temperature and time, and then distill off the excess diol monomer and small molecular by-products under reduced pressure to obtain a hydroxyl-terminated high molecular weight polyester polyol.

2. The method for preparing hydroxyl-terminated high molecular weight polyester polyols using a metal-free catalyst as claimed in claim 1, characterized in that: In the step 1, the diol monomer is any one or more of ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, dipropylene glycol, 2-methyl-1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol; The cyclic dicarboxylic acid is a dicarboxylic acid that is easy to form a five-membered cyclic anhydride or a dicarboxylic acid that is easy to form a six-membered cyclic anhydride; The acid anhydride is any one or more of succinic anhydride, 2-methylsuccinic anhydride, 2-phenylsuccinic anhydride, 2-benzylsuccinic anhydride, 2,2-dimethylsuccinic anhydride, 2,3-dimethylsuccinic anhydride, 2,3-diphenylsuccinic anhydride, 1,2-cyclosuccinic anhydride, 2,2,3,3-tetramethylsuccinic anhydride, maleic anhydride, glutaric anhydride, 2-ketoglutaric anhydride, 1,3-acetone dicarboxylic anhydride, 2-methylglutaric anhydride, 3-methylglutaric anhydride, 3-phenylglutaric anhydride, 2,2-dimethylglutaric anhydride, 3,3-dimethylglutaric anhydride, 3-ethyl-3-methylglutaric anhydride, 3,3-tetramethyleneglutaric anhydride, phthalic anhydride, 1,2,5,6-tetrahydrophthalic anhydride, and 1,2-cyclohexanedicarboxylic anhydride.

3. The method for preparing hydroxyl-terminated high molecular weight polyester polyols using a metal-free catalyst as claimed in claim 2, characterized in that: The cyclic dicarboxylic acid is any one or more of succinic acid, 2-methylsuccinic acid, 2-phenylsuccinic acid, 2-benzylsuccinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylsuccinic acid, 2,3-diphenylsuccinic acid, 1,2-cyclobutanedicarboxylic acid, 2,2,3,3-tetramethylsuccinic acid, maleic acid, glutaric acid, 2-ketoglutaric acid, 1,3-acetonedicarboxylic acid, 2-methylglutaric acid, 3-methylglutaric acid, 3-phenylglutaric acid, 2,2-dimethylglutaric acid, 3,3-dimethylglutaric acid, 3-ethyl-3-methylglutaric acid, 3,3-tetramethyleneglutaric acid, phthalic acid, 1,2,5,6-tetrahydrophthalic acid, and 1,2-cyclohexanedicarboxylic acid.

4. The method for preparing hydroxyl-terminated high molecular weight polyester polyols using a metal-free catalyst as claimed in any one of claims 1 to 3, characterized in that: In the step 1, the molar ratio of the excess molar ratio of component 1 to the diol monomer is 1.2 to 2.0; The predetermined reaction temperature in step 1 is 100-300° C., and the reaction time is 6-48 hours.

5. The method for preparing hydroxyl-terminated polymer polyester polyols using a metal-free catalyst as claimed in any one of claims 1 to 3, characterized in that: In the step 2, the temperature not lower than the boiling point of the anhydride formed by the cyclic dicarboxylic acid is 100 to 300°C; The reaction pressure of the reduced pressure distillation is ≤300Pa, and the reaction time is 4 to 48 hours.

6. The method for preparing hydroxyl-terminated high molecular weight polyester polyol using a metal-free catalyst as claimed in any one of claims 1 to 3, characterized in that: In the step 3, the predetermined ratio of solvent added is: the mass ratio of the carboxyl-terminated high molecular weight polyester product in the reactor to the solvent is 100:1000 to 100:10; The solvent is any one or more of ethyl acetate, butyl acetate, acetone, butanone, tetrahydrofuran, dichloromethane, chloroform, carbon tetrachloride, N,N-dimethylamide, and tetrachloroethane; The predetermined ratio of thionyl chloride is added: the mass ratio of the carboxyl-terminated high molecular weight polyester product in the reactor to thionyl chloride is 100:1 to 100:50; The predetermined reaction temperature is 50-90° C.; the reaction time is 2-6 hours.

7. The method for preparing hydroxyl-terminated polymer polyester polyols using a metal-free catalyst as claimed in any one of claims 1 to 3, characterized in that: In step 4, the excess diol monomer is: the amount of diol monomer used is greater than the amount required to react with the high molecular weight terminal acyl chloride group of the diacid chloride polymer and the remaining thionyl chloride in step 2; The diol monomer is any one or more of ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, dipropylene glycol, 2-methyl-1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol; The mass ratio of the diacid chloride polymer to the diol monomer in the reactor is 100:10 to 100:50; The catalyst is any one or more of triethylamine, tetramethylbutylene diamine, triethylene diamine, tetramethylbutylene diamine, N-ethylmorpholine, and N,N'-diethylpiperazine; The catalyst dosage is 0.01-1% of the total solid weight content. The predetermined reaction temperature is -50 to 80°C, and the reaction time is 2 to 6 hours; The reduced pressure distillation temperature is 100-150° C., the pressure is ≤300 Pa, and the duration is 2-6 hours.

8. A hydroxy-terminated polymer polyester polyol, characterized in that: The present invention is prepared by the method for preparing hydroxy-terminated high molecular weight polyester polyol without metal catalyst as claimed in any one of claims 1 to 7, wherein the hydroxy-terminated high molecular weight polyester polyol has a hydroxyl value of 4 to 20 mgKOH / g and an acid value of ≤0.5 mgKOH / g.

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