Waterborne polyester resin as well as preparation method and application thereof

Abstract

The invention relates to a preparation method of hydrolysis-resistant polyester resin, which specifically comprises the following steps: in the presence of a catalyst, carrying out esterification reaction on dihydric alcohol, dibasic acid or ester thereof, and organic acid or acid anhydride containing carbon-carbon double bonds, carrying out condensation polymerization reaction after the esterification reaction is finished, and then in the presence of a catalyst, carrying out condensation polymerization reaction to obtain the hydrolysis-resistant polyester resin. And adding amino acid with 6-16 carbon atoms into the reaction system for reaction. The prepared polyester resin has the advantages of hydrolysis resistance and good storage stability.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a water-based polyester resin and a preparation method and application thereof. Background Art

[0002] Because coatings prepared from solvent-based polyester resins contain large amounts of volatile organic compounds (VOCs), their volatilization during film formation leads to environmental pollution and resource waste. Water-based polyester resins inherit the advantages of oil-based polyester resins, such as excellent film fullness, high gloss, weather resistance, gloss retention, and excellent flexibility, making them widely used in various industries such as automobiles, canned goods, building materials, and home appliances. However, traditional water-based polyesters have poor hydrolysis resistance. The ester bonds are easily hydrolyzed and scissioned to form alcohols and carboxylic acids. The resulting carboxylic acids further catalyze the hydrolysis reaction, accelerating chain scission, and rapidly deteriorating the physical, chemical, and mechanical properties of the polyester. This severely limits the environmentally friendly upgrade and widespread application of water-based polyesters.

[0003] Patent CN104629034A provides a hydrolysis-resistant polyester. This patent finds that polyesters with a primary alcohol-carboxylic acid ester bond ratio of less than or equal to 75% exhibit superior hydrolysis resistance compared to polyesters with ester bonds composed entirely of primary alcohols and carboxylic acids. Polyesters with a primary alcohol-carboxylic acid ester bond ratio of less than or equal to 50% are more hydrolysis-resistant. Polyesters with a primary alcohol-carboxylic acid ester bond ratio of less than or equal to 30% are particularly hydrolysis-resistant, and the most hydrolysis-resistant polyesters are those with no primary alcohol-carboxylic acid ester bonds. However, this patent imposes strict requirements on the ratio of primary alcohol to carboxylic acid, which to some extent limits the freedom of choice of the monomeric alcohol component in the polyester.

[0004] Patent CN101215730A uses a method of modifying polyester by adding a hydrolysis inhibitor, carbodiimide. While this method improves hydrolysis resistance, it also results in high production costs and the generation of a large amount of harmful volatiles during the production process, impacting the environment and human health.

[0005] Patent CN111378102A discloses a hydrolysis-resistant water-based polyester resin, primarily produced by reacting the following raw materials: an organic sulfonate, a dibasic alcohol, a dibasic ester, a catalyst, a polyhydroxyalkane, and a dibasic acid, the dibasic acid including at least isophthalic acid. The introduction of a small amount of sulfonic acid groups imparts excellent water-dispersibility to the polyester resin. The symmetrical polymer formed by the dibasic ester (e.g., dimethyl terephthalate) and the dibasic alcohol (e.g., neopentyl glycol) generates van der Waals hydrogen bonds between the molecules, reducing the intrusion of water molecules and improving the hydrolysis resistance of the ester bonds. However, the esterification process, involving a stepwise temperature increase reaction, is costly and unsuitable for large-scale production. Summary of the Invention

[0006] In order to solve the above problems, the purpose of the present invention is to provide a water-based polyester resin with good hydrolysis resistance and storage stability.

[0007] Solutions for solving problems In one aspect, the present invention provides a method for preparing a hydrolysis-resistant water-based polyester resin, the method comprising: (1) Adding diol, dibasic acid or its ester, organic acid or acid anhydride containing carbon-carbon double bond and catalyst into a reactor to carry out esterification reaction to obtain a prepolymer; (2) After the esterification reaction is completed, the prepolymer is subjected to a polycondensation reaction; (3) adding an amino acid having 6 to 16 carbon atoms and a catalyst to the reaction system and continuing the reaction to obtain the hydrolysis-resistant water-soluble polyester resin; The molar amount of the organic acid or anhydride containing a carbon-carbon double bond is 10 to 35% of the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond; The molar amount of the amino acid with 6 to 16 carbon atoms is 5 to 30% of the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond.

[0008] Preferably, in step (1), the dibasic acid or its ester is selected from one or more of terephthalic acid or its ester, phthalic acid or its ester, adipic acid and sebacic acid.

[0009] Preferably, the dibasic acid or its ester is a mixture of terephthalic acid or its ester, phthalic acid or its ester and sebacic acid; the molar ratio of terephthalic acid or its ester, phthalic acid or its ester and sebacic acid is 1:1:(0.1-2); preferably 1:1:(0.5-1.5).

[0010] Preferably, the dibasic acid or its ester is a mixture of terephthalic acid or its ester, phthalic acid or its ester and adipic acid, and the molar ratio of terephthalic acid or its ester, phthalic acid or its ester and adipic acid is 1:1:(0.1-2); preferably 1:1:(0.5-1).

[0011] Preferably, in step (1), the diol is selected from one or more of ethylene glycol, neopentyl glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol and 2-methyl-1,3-propanediol, preferably one or more of ethylene glycol, neopentyl glycol and 2-methyl-1,3-propanediol.

[0012] Preferably, the diol is a mixture of ethylene glycol and neopentyl glycol, and the molar ratio of the ethylene glycol to the neopentyl glycol is (3-5):1, preferably 4:1.

[0013] Preferably, the diol is a mixture of 2-methyl-1,3-propanediol and neopentyl glycol, and the molar ratio of the 2-methyl-1,3-propanediol to the neopentyl glycol is (0.5-2):1, preferably 1:1.

[0014] Preferably, in step (1), the organic acid or anhydride containing a carbon-carbon double bond is selected from one or more of maleic anhydride, fumaric acid and itaconic acid, preferably maleic anhydride.

[0015] Preferably, in step (1), the catalyst is selected from one or more of tetrabutyl titanate, tetraethyl titanate, dibutyltin oxide, tin chloride, stannous octoate, dibutyltin maleate, and acetates of Na, Zn, Mn, Mg, Ca, and Co, and is more preferably one or more of acetates of Na, Zn, and tetrabutyl titanate.

[0016] Preferably, in step (1), the molar ratio of the diol to the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond is (1-2):1.

[0017] Preferably, in step (1), the reaction system is heated at a rate of 0.4-0.6°C / min to carry out the esterification reaction, and the esterification reaction temperature is controlled to be 220-240°C.

[0018] Preferably, in step (1), the esterification reaction is carried out at a stirring rate of 60-150 rpm.

[0019] Preferably, in step (1), the pressure of the esterification reaction is controlled to be 0.1 MPa.

[0020] Preferably, in step (2), the polycondensation reaction occurs in the presence of an auxiliary agent, and the auxiliary agent is selected from trimethyl phosphate and / or triethyl phosphate.

[0021] Preferably, in step (2), the temperature of the polycondensation reaction is controlled to be 230-250° C., and the time of the polycondensation reaction is 60-150 min.

[0022] Preferably, in step (2), the polycondensation reaction is carried out at a stirring rate of 30 to 100 rpm.

[0023] Preferably, in step (2), the pressure of the polycondensation reaction is controlled to be below 100 Pa.

[0024] Preferably, in step (3), the amino acid having 6 to 16 carbon atoms is selected from one or more of 6-aminohexanoic acid, 8-aminooctanoic acid, 10-aminodecanoic acid, 12-aminododecanoic acid, 14-aminotetradecanoic acid or 16-aminohexadecanoic acid, preferably one or more of 10-aminodecanoic acid, 12-aminododecanoic acid, 14-aminotetradecanoic acid and 16-aminohexadecanoic acid.

[0025] Preferably, in step (3), the catalyst is selected from one or more of tetramethylguanidine, 1,8-diazabicycloundec-7-ene, N,N-dimethylcyclohexylamine, dimethylethylene glycolamine and triethylenediamine.

[0026] Preferably, the molar amount of the amino acid having 6 to 16 carbon atoms is 10 to 25% of the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond.

[0027] Preferably, in step (3), the reaction temperature is controlled to be 80-180° C., and the reaction time is 30-100 min.

[0028] Preferably, the reaction in step (3) is carried out at a stirring rate of 60 to 150 rpm.

[0029] Preferably, the method specifically comprises: adding a diol, a dibasic acid or an ester thereof, an organic acid or anhydride containing a carbon-carbon double bond, and an organic metal catalyst into a reactor, heating to 220-240° C. for esterification reaction, cooling to 180-220° C. when the amount of the esterification distillate reaches more than 90% of the theoretical value, adding an auxiliary agent, then maintaining the polycondensation temperature at 230-250° C., controlling the vacuum degree of the reaction system to below 100 Pa, reacting for 60-150 minutes, cooling the reaction system to 80-180° C., adding an amino acid with 6-16 carbon atoms and an organic base catalyst, and reacting for 30-100 minutes to obtain the hydrolysis-resistant water-based polyester resin.

[0030] In one aspect, the present invention provides a hydrolysis-resistant water-soluble polyester resin obtained according to any one of the preparation methods described above.

[0031] In one aspect, the present invention provides a composition comprising a hydrolysis-resistant polyester resin obtained by any of the preparation methods described above or a hydrolysis-resistant water-soluble polyester resin described above.

[0032] In one aspect, the present invention provides a hydrolysis-resistant polyester resin obtained by any of the preparation methods described above, or use of the hydrolysis-resistant polyester resin described above in a water-based coating or a water-based adhesive.

[0033] Effects of the Invention This invention utilizes melt copolymerization and Michael addition reactions to introduce carbon-carbon double bonds and long carboxyl side chains into the polyester backbone, making the resin water-based. The long side chains protect the ester groups on the backbone, imparting hydrolysis resistance to the polyester. This method not only improves the hydrolysis resistance of the water-based resin but also maintains other properties (such as viscosity, hardness, and heat resistance), ensuring its effectiveness. The method is simple and easy to implement, requiring no specialized equipment and reducing production costs. Compared to existing methods that require specialized equipment and complex procedures, the present invention is more practical and economical. The water-based resin of the present invention exhibits excellent hydrolysis resistance, meeting the requirements of specialized applications, such as those in high-temperature and high-humidity environments or those requiring long-term storage, such as food and pharmaceutical packaging. Compared to existing water-based resins, the water-based resin of the present invention offers broader application prospects. DETAILED DESCRIPTION

[0034] To make the technical solutions and beneficial effects of the present invention more clearly understood, the following is a detailed description by listing specific embodiments. Unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application belongs.

[0035] If no specific techniques or conditions are specified in the following examples, the experiments were generally carried out in accordance with conventional techniques or conditions described in the literature in the art, or in accordance with the product instructions and the conditions recommended by the manufacturer.

[0036] Unless otherwise indicated, various starting materials, materials and reagents were either commercially available or synthesized according to known methods.

[0037] After extensive and in-depth research, the inventors designed a resin structure with larger side groups and increased the hydrophobic groups around the ester bonds, thereby reducing the hydrolysis of the ester bonds and solving the problems of easy hydrolysis and poor storage stability of water-based polyester resins. The inventors used a melt condensation method to synthesize a water-based polyester resin that is resistant to hydrolysis and has good storage stability.

[0038] In one aspect, the present invention provides a method for preparing a hydrolysis-resistant polyester resin, the method comprising: (1) Adding diol, dibasic acid or its ester, organic acid or acid anhydride containing carbon-carbon double bond and catalyst into a reactor to carry out esterification reaction to obtain a prepolymer; (2) After the esterification reaction is completed, the prepolymer is subjected to a polycondensation reaction; (3) adding an amino acid having 6 to 16 carbon atoms and a catalyst to the reaction system and continuing the reaction to obtain the hydrolysis-resistant water-soluble polyester resin; The molar amount of the organic acid or anhydride containing a carbon-carbon double bond is 10 to 35% of the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond; The molar amount of the amino acid with 6 to 16 carbon atoms is 5 to 30% of the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond.

[0039] The present invention has found through research that the number of carbon atoms in long-chain amino acids is 6 to 16 carbon atoms. If the number of carbon atoms is less than 6, the side chain has a poor protection effect on the main chain ester group, and the resin has poor hydrolysis resistance; if the number of carbon atoms is greater than 16, the water solubility of the resin is affected, making the resin difficult to be water-based.

[0040] In certain embodiments, in step (1), the dibasic acid or its ester is selected from one or more of terephthalic acid or its ester, phthalic acid or its ester, adipic acid and sebacic acid.

[0041] In certain embodiments, the dibasic acid or its ester is a mixture of terephthalic acid or its ester, phthalic acid or its ester and sebacic acid; the molar ratio of terephthalic acid or its ester, phthalic acid or its ester and sebacic acid is 1:1:(0.1~2), for example, 1:1:0.2, 1:1:0.3, 1:1:0.4, 1:1:0.5, 1:1:0.6, 1:1:0.7, 1:1:0.8, 1:1:0.9, 1:1:1, 1:1:1.1, 1:1:1.2, 1:1:1.3, 1:1:1.4, 1:1:1.5, 1:1:1.6, 1:1:1.7, 1:1:1.8, 1:1:1.9, etc.

[0042] In certain embodiments, the molar ratio of terephthalic acid or its ester, phthalic acid or its ester, and sebacic acid is 1:1:(0.5-1.5).

[0043] In certain embodiments, the molar ratio of terephthalic acid or its ester, phthalic acid or its ester, and sebacic acid is 1:1:(0.5-1).

[0044] In certain embodiments, the dibasic acid or its ester is a mixture of terephthalic acid or its ester, phthalic acid or its ester and adipic acid, and the molar ratio of terephthalic acid or its ester, phthalic acid or its ester and adipic acid is 1:1:(0.1~2), for example, 1:1:0.2, 1:1:0.3, 1:1:0.4, 1:1:0.5, 1:1:0.6, 1:1:0.7, 1:1:0.8, 1:1:0.9, 1:1:1, 1:1:1.1, 1:1:1.2, 1:1:1.3, 1:1:1.4, 1:1:1.5, 1:1:1.6, 1:1:1.7, 1:1:1.8, 1:1:1.9, etc.

[0045] In certain embodiments, the molar ratio of terephthalic acid or its ester, phthalic acid or its ester, and adipic acid is 1:1:(0.5-1).

[0046] In certain embodiments, in step (1), the diol is selected from one or more of ethylene glycol, neopentyl glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol and 2-methyl-1,3-propanediol.

[0047] In certain embodiments, the diol is selected from one or more of ethylene glycol, neopentyl glycol, and 2-methyl-1,3-propanediol.

[0048] In certain embodiments, the diol is a mixture of ethylene glycol and neopentyl glycol, and the molar ratio of the ethylene glycol to the neopentyl glycol is (3-5):1, for example, 3.5:1, 4:1, 4.5:1, 5:1, etc.

[0049] In certain embodiments, the molar ratio of the ethylene glycol to the neopentyl glycol is 4:1.

[0050] In certain embodiments, the diol is a mixture of 2-methyl-1,3-propanediol and neopentyl glycol, and the molar ratio of the 2-methyl-1,3-propanediol to the neopentyl glycol is (0.5-2):1, for example, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, etc.

[0051] In certain embodiments, the molar ratio of the 2-methyl-1,3-propanediol to the neopentyl glycol is 1:1.

[0052] In certain embodiments, in step (1), the organic acid or anhydride containing a carbon-carbon double bond is selected from one or more of maleic anhydride, fumaric acid and itaconic acid.

[0053] In certain embodiments, the organic acid or anhydride containing a carbon-carbon double bond is selected from maleic anhydride.

[0054] In certain embodiments, in step (1), the catalyst is an organometallic catalyst.

[0055] In certain embodiments, in step (1), the catalyst is selected from one or more of tetrabutyl titanate, tetraethyl titanate, dibutyltin oxide, tin chloride, stannous octoate, dibutyltin maleate, and acetates of Na, Zn, Mn, Mg, Ca, and Co.

[0056] In certain embodiments, in step (1), the catalyst is selected from one or more of Na, Zn acetate and tetrabutyl titanate.

[0057] In certain embodiments, in step (1), the catalyst is selected from a mixture of Na, Zn acetate and tetrabutyl titanate.

[0058] In certain embodiments, the amount of the catalyst is 250-400 ppm of the total mass of the diol, the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond, for example, 260 ppm, 270 ppm, 280 ppm, 290 ppm, 300 ppm, 310 ppm, 320 ppm, 330 ppm, 340 ppm, 350 ppm, 360 ppm, 370 ppm, 380 ppm, 390 ppm, 400 ppm, etc.

[0059] In certain embodiments, the amount of the catalyst is 300-400 ppm based on the total mass of the diol, the dibasic acid or its ester, and the organic acid or anhydride containing a carbon-carbon double bond.

[0060] In certain embodiments, in step (1), the molar ratio of the diol to the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond is (1-2):1, for example, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, etc.

[0061] In certain embodiments, in step (1), the molar ratio of the diol to the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond is (1.2-1.8):1.

[0062] In certain embodiments, the molar amount of the organic acid or anhydride containing a carbon-carbon double bond is 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, etc., of the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond.

[0063] In certain embodiments, the molar amount of the organic acid or anhydride containing a carbon-carbon double bond is 10-30% of the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond.

[0064] In certain embodiments, in step (1), the reaction system is heated at a rate of 0.4-0.6°C / min to carry out the esterification reaction, and the esterification reaction temperature is controlled to be 220-240°C (e.g., 225°C, 230°C, 235°C, 240°C, etc.).

[0065] In certain embodiments, in step (1), the reaction system is heated at a rate of 0.5°C / min to carry out the esterification reaction.

[0066] In certain embodiments, in step (1), the esterification reaction is carried out at a stirring rate of 60 to 150 rpm (e.g., 70 rpm, 80 rpm, 90 rpm, 100 rpm, 110 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm, etc.).

[0067] In certain embodiments, in step (1), the pressure of the esterification reaction is controlled to be 0.1 MPa.

[0068] In certain embodiments, step (1) specifically comprises: adding a diol, a dibasic acid or an ester thereof, an organic acid or anhydride containing a carbon-carbon double bond, and a catalyst into a reactor, heating the reactor to 100-150° C. for the first time, stirring the reactor, heating the reactor to 220-240° C. for the second time at a rate of 0.4-0.6° C. / min, and performing an esterification reaction. When the amount of the esterification distillate reaches more than 90% of the theoretical value, the esterification reaction is terminated.

[0069] In certain embodiments, in step (2), the polycondensation reaction occurs in the presence of an auxiliary agent, and the auxiliary agent is selected from trimethyl phosphate and / or triethyl phosphate.

[0070] In certain embodiments, in step (2), the amount of the auxiliary agent is 100-200 ppm of the total mass of the diol, the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond, for example, 100 ppm, 105 ppm, 110 ppm, 115 ppm, 120 ppm, 125 ppm, 130 ppm, 140 ppm, 145 ppm, 150 ppm, 155 ppm, 160 ppm, 165 ppm, 170 ppm, 175 ppm, 180 ppm, 185 ppm, 190 ppm, 195 ppm, 200 ppm, etc.

[0071] In certain embodiments, in step (2), the temperature of the polycondensation reaction is controlled to be 2300-250° C., and the time of the polycondensation reaction is 60-150 min.

[0072] In certain embodiments, in step (2), the polycondensation reaction is carried out at a stirring rate of 30 to 100 rpm (e.g., 40 rpm, 50 rpm, 60 rpm, 70 rpm, 80 rpm, 90 rpm, 100 rpm, etc.).

[0073] In certain embodiments, in step (2), the pressure of the polycondensation reaction is controlled to be below 100 Pa.

[0074] In certain embodiments, in step (3), the amino acid having 6 to 16 carbon atoms is selected from one or more of 6-aminohexanoic acid, 8-aminooctanoic acid, 10-aminodecanoic acid, 12-aminododecanoic acid, 14-aminotetradecanoic acid, or 16-aminohexadecanoic acid.

[0075] In certain embodiments, in step (3), the amino acid having 6 to 16 carbon atoms is selected from one or more of 10-aminodecanoic acid, 12-aminododecanoic acid, 14-aminotetradecanoic acid, and 16-aminohexadecanoic acid.

[0076] In certain embodiments, in step (3), the catalyst is an organic base catalyst.

[0077] In certain embodiments, in step (3), the catalyst is selected from one or more of tetramethylguanidine, 1,8-diazabicycloundec-7-ene, N,N-dimethylcyclohexylamine, dimethylethylene glycolamine, and triethylenediamine.

[0078] In certain embodiments, in step (3), the catalyst is selected from tetramethylguanidine.

[0079] In certain embodiments, in step (3), the amount of the catalyst used is 100-200 ppm of the total mass of the diol, the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond, for example, 100 ppm, 105 ppm, 110 ppm, 115 ppm, 120 ppm, 125 ppm, 130 ppm, 140 ppm, 145 ppm, 150 ppm, 155 ppm, 160 ppm, 165 ppm, 170 ppm, 175 ppm, 180 ppm, 185 ppm, 190 ppm, 195 ppm, 200 ppm, etc.

[0080] In certain embodiments, in step (3), the amount of the catalyst used is 100-150 ppm of the total mass of the diol, the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond.

[0081] In certain embodiments, the molar amount of the amino acid having 6 to 16 carbon atoms is 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, etc., of the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond. The addition amount of the long-chain amino acid is 5 to 30% by mole of the dibasic acid. If it is less than 5 mol%, effective protection of the main chain ester group cannot be formed, resulting in poor hydrolysis resistance of the resin. If it exceeds 30 mol%, because the introduction of the long-chain amino acid relies on the dibasic acid / anhydride containing a carbon-carbon double bond, and the long-chain amino acid reacts with the carbon-carbon double bond in a 1:1 ratio, the reaction requires more than 30% of the dibasic acid / anhydride containing a carbon-carbon double bond, which can lead to easy crosslinking during the resin synthesis process.

[0082] In certain embodiments, the molar amount of the amino acid having 6 to 16 carbon atoms is 5 to 25% of the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond.

[0083] In certain embodiments, in step (3), the reaction temperature is controlled to be 80-180°C (e.g., 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, etc.), and the reaction time is 30-100 min (e.g., 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, etc.).

[0084] In certain embodiments, the reaction in step (3) is carried out at a stirring rate of 60 to 150 rpm (e.g., 70 rpm, 80 rpm, 90 rpm, 100 rpm, 110 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm, etc.).

[0085] In certain embodiments, the method specifically includes: adding a diol, a dibasic acid or its ester, an organic acid or anhydride containing a carbon-carbon double bond, and an organic metal catalyst into a reactor, heating to 220-240° C. for an esterification reaction, when the amount of the esterification distillate reaches more than 90% of the theoretical value, cooling to 180-220° C., adding an auxiliary agent, maintaining the polycondensation temperature at 230-250° C., controlling the vacuum degree of the reaction system to below 100 Pa, reacting for 60-150 minutes, cooling the reaction system to 80-180° C., adding an amino acid with a carbon number of 6-16 and an organic base catalyst, and reacting for 30-100 minutes to obtain the hydrolysis-resistant polyester resin.

[0086] The present invention proposes a novel method for improving the hydrolysis resistance of waterborne resins, which can effectively improve the hydrolysis resistance of the resin and ensure the resin's performance. Furthermore, the waterborne polyester resin provided by the present invention can reduce the performance degradation of the waterborne resin caused by hydrolysis during use, extend its service life, and meet the market demand for high-performance waterborne resins. Finally, the technical solution is simple to operate, low in cost, conducive to large-scale production, and has broad market application prospects.

[0087] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present invention and are not intended to limit the scope of the invention. The experimental methods in the following examples, for which no specific conditions are specified, are generally based on conventional conditions or the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are by weight. Example 1

[0088] Under nitrogen protection, 251.89 g of terephthalic acid, 251.89 g of isophthalic acid, 204.43 g of sebacic acid, 99.01 g of maleic anhydride, 376.44 g of ethylene glycol, 157.91 g of neopentyl glycol, 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate and 0.16 g of zinc acetate were added to a 2 L stainless steel reactor at the same time. The system pressure was maintained at 0.1 MPa. The reaction temperature was raised to 120 ° C. Stirring was started and the stirring rate was set to 1. 00rpm, then program the temperature, set the heating rate to 0.5℃ / min, the temperature reaches 235℃, and maintain the temperature until the amount of by-products reaches more than 90% of the theoretical value to end the esterification; cool the system to 200℃, add 0.2g of trimethyl phosphate, stir for 30min and then start polycondensation, the stirring rate is 60rpm, the polycondensation temperature is 240℃, the vacuum degree is 100Pa, and the polycondensation time is 120min; then cool the system to 150℃, add 163.24g of 12-aminododecanoic acid and 0.16g of tetramethylguanidine, stir at a rate of 100rpm, stir for 60min and then remove from the kettle. Example 2

[0089] Under nitrogen protection, 255.28 g of terephthalic acid, 255.28 g of isophthalic acid, 207.19 g of sebacic acid, 100.37 g of maleic anhydride, 381.51 g of ethylene glycol, 160.04 g of neopentyl glycol, 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate and 0.16 g of zinc acetate were added to a 2 L stainless steel reactor at the same time. The system pressure was maintained at 0.1 MPa, the reaction temperature was raised to 120 ° C, stirring was started, and the stirring rate was set to 1. 00rpm, then program the temperature, set the heating rate to 0.5℃ / min, the temperature reaches 235℃, maintain the temperature until the amount of by-products reaches more than 90% of the theoretical value to end the esterification; cool the system to 200℃, add 0.2g of trimethyl phosphate, stir for 30min and then start polycondensation, the stirring rate is 60rpm, the polycondensation temperature is 240℃, the vacuum degree is 100Pa, and the polycondensation time is 120min; then cool the system to 150℃, add 143.89g of 10-aminodecanoic acid and 0.16g of tetramethylguanidine, stir at a rate of 100rpm, stir for 60min and then remove from the kettle. Example 3

[0090] Under nitrogen protection, 247.43 g of terephthalic acid, 247.43 g of isophthalic acid, 200.82 g of sebacic acid, 97.29 g of maleic anhydride, 369.78 g of ethylene glycol, 155.12 g of neopentyl glycol, 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate and 0.16 g of zinc acetate were added to a 2 L stainless steel reactor at the same time. The system pressure was maintained at 0.1 MPa. The reaction temperature was raised to 120 ° C. Stirring was started and the stirring rate was set to 1. 00rpm, then program the temperature, set the heating rate to 0.5℃ / min, the temperature reaches 235℃, and maintain the temperature until the amount of by-products reaches more than 90% of the theoretical value to end the esterification; cool the system to 200℃, add 0.2g of trimethyl phosphate, stir for 30min and then start polycondensation, the stirring rate is 60rpm, the polycondensation temperature is 240℃, the vacuum degree is 100Pa, and the polycondensation time is 120min; then cool the system to 150℃, add 163.24g of 16-aminohexadecanoic acid and 0.16g of tetramethylguanidine, stir at a rate of 100rpm, stir for 60min and then remove from the kettle. Example 4

[0091] Under nitrogen protection, 246.13 g of terephthalic acid, 246.13 g of isophthalic acid, 199.97 g of sebacic acid, 96.88 g of maleic anhydride, 368.23 g of ethylene glycol, 154.47 g of neopentyl glycol, 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate and 0.16 g of zinc acetate were added to a 2 L stainless steel reactor at the same time. The system pressure was maintained at 0.1 MPa, the reaction temperature was raised to 120 ° C, stirring was started, and the stirring rate was set to 1. 00rpm, then program the temperature, set the heating rate to 0.5℃ / min, the temperature reaches 235℃, and maintain the temperature until the amount of by-products reaches more than 90% of the theoretical value to end the esterification; cool the system to 200℃, add 0.2g of trimethyl phosphate, stir for 30min and then start polycondensation, the stirring rate is 60rpm, the polycondensation temperature is 240℃, the vacuum degree is 100Pa, and the polycondensation time is 120min; then cool the system to 150℃, add 100.64g of 16-aminohexadecanoic acid, 93.93g of 14-aminotetradecanoic acid, and 0.16g of tetramethylguanidine, the stirring rate is 100rpm, and stir for 60min before unloading. Example 5

[0092] Under nitrogen protection, 264.53 g of terephthalic acid, 264.53 g of isophthalic acid, 322.08 g of sebacic acid, 52.11 g of maleic anhydride, 395.34 g of ethylene glycol, 165.84 g of neopentyl glycol, 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate and 0.16 g of zinc acetate were added to a 2 L stainless steel reactor at the same time. The system pressure was maintained at 0.1 MPa. The reaction temperature was raised to 120 ° C. Stirring was started and the stirring rate was set to 1. 00rpm, then program the temperature, set the heating rate to 0.5℃ / min, the temperature reaches 235℃, and maintain the temperature until the amount of by-products reaches more than 90% of the theoretical value to end the esterification; cool the system to 200℃, add 0.2g of trimethyl phosphate, stir for 30min and start polycondensation, the stirring rate is 60rpm, the polycondensation temperature is 240℃, the vacuum degree is 100Pa, and the polycondensation time is 120min; then cool the system to 150℃, add 85.72g of 12-aminododecanoic acid and 0.16g of tetramethylguanidine, stir at a rate of 100rpm, stir for 60min and then remove from the kettle. Example 6

[0093] Under nitrogen protection, 198.17 g of terephthalic acid, 198.17 g of isophthalic acid, 193.00 g of sebacic acid, 140.26 g of maleic anhydride, 355.39 g of ethylene glycol, 149.08 g of neopentyl glycol, 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate and 0.16 g of zinc acetate were added to a 2 L stainless steel reactor at the same time. The system pressure was maintained at 0.1 MPa. The reaction temperature was raised to 120 ° C. Stirring was started and the stirring rate was set to 1. 00rpm, then program the temperature, set the heating rate to 0.5℃ / min, the temperature reaches 235℃, maintain the temperature until the amount of by-products reaches more than 90% of the theoretical value to end the esterification; cool the system to 200℃, add 0.2g of trimethyl phosphate, stir for 30min and then start polycondensation, the stirring rate is 60rpm, the polycondensation temperature is 240℃, the vacuum degree is 100Pa, and the polycondensation time is 120min; then cool the system to 150℃, add 231.17g of 12-aminododecanoic acid and 0.16g of tetramethylguanidine, stir at a rate of 100rpm, stir for 30min and then remove from the kettle. Example 7

[0094] Under nitrogen protection, 257.36 g of dimethyl terephthalate, 257.36 g of dimethyl isophthalate, 129.13 g of adipic acid, 86.58 g of maleic anhydride, 298.60 g of 2-methyl-1,3-propanediol, 345.09 g of neopentyl glycol, and 0.16 g of catalyst were added to a 2 L stainless steel reactor. g tetrabutyl titanate, 0.16 g sodium acetate and 0.16 g zinc acetate were added simultaneously, maintaining the system pressure at 0.1 MPa, the reaction temperature was raised to 120° C., stirring was started, the stirring rate was set to 100 rpm, and then the temperature was programmed to rise at a heating rate of 0.5° C. / min until the temperature reached 235° C. and the temperature was maintained until the amount of by-products reached more than 90% of the theoretical value to terminate the esterification; the system was cooled to 200° C., 0.2 g trimethyl phosphate was added, and after stirring for 30 min, polycondensation was started at a stirring rate of 60 rpm, the polycondensation temperature was 240° C., the vacuum degree was 100 Pa, and the polycondensation time was 120 min; the system was then cooled to 150° C., 231.17 g 12-aminododecanoic acid and 0.16 g tetramethylguanidine were added, the stirring rate was 100 rpm, and the mixture was stirred for 60 min before being discharged from the kettle.

[0095] Comparative Example 1 On the basis of Example 1, the amounts of maleic anhydride and 12-aminododecanoic acid were reduced to 1 / 5 of those in Example 1, while the rest remained unchanged.

[0096] Comparative Example 2 On the basis of Example 1, the amounts of maleic anhydride and 12-aminododecanoic acid were increased to 2.5 times of those in Example 1, and the polycondensation time was reduced from 120 min to 60 min, while the rest remained unchanged.

[0097] The performance of the waterborne polyester resins prepared in Examples 1 to 7 and Comparative Examples 1 to 2 was characterized.

[0098] Glass transition temperature (Tg): The test was conducted using a TA Q20 differential scanning calorimeter with a nitrogen atmosphere flow rate of 20 mL / min. During the test, a 5 mg sample was placed in an alumina sample pan. The test process was as follows: the sample was heated from 30°C to 180°C at a heating rate of 10°C / min and maintained in this state for 2 minutes to eliminate the thermal history. The sample was then cooled to 30°C at a cooling rate of 10°C / min. Subsequently, the sample underwent a second heating process from 30°C to 180°C at a heating rate of 10°C / min. The glass transition temperature of the sample was obtained by the second heating process.

[0099] Intrinsic viscosity test (IV): using an Ubbelohde viscometer, using o-chlorophenol as the solvent, measured at a temperature of 35°C. The intrinsic viscosity is calculated as follows:

[0100] Where: η: intrinsic viscosity, mL / g; : specific viscosity; : viscosity ratio; c: polymer concentration, mol / L; t: sample elution time, s; t0: blank sample elution time, s.

[0101] The acid value test refers to the national standard GB / T 6743-2008 "Determination of partial acid value and total acid value of polyester resins for plastics, paints and varnishes".

[0102] Preparation method of aqueous polyester dispersion: take 30g of the polyester prepared above, add 70g of deionized water, add 5g of N,N-dimethylethanolamine and stir evenly to obtain an aqueous polyester dispersion with a solid content of 30%.

[0103] Table 1: Test results of intrinsic viscosity, Tg and acid value of the waterborne polyester resins prepared in Examples 1-7 and Comparative Examples 1-2.

[0104] Table 1

[0105] In Comparative Example 2, since the amount of maleic anhydride added was relatively large, the system was easily cross-linked during the polycondensation process, and therefore it was difficult to obtain a sample with a relatively large intrinsic viscosity.

[0106] The above samples (except Comparative Example 2) were dissolved and their acid value changes during storage were monitored. Polyester hydrolysis produces acids and alcohols, so monitoring the acid value changes can be used to determine their hydrolysis resistance. Storage conditions were a constant temperature of 50°C. The hydrolysis resistance test results of the water-based polyester resins prepared in Examples 1-7 and Comparative Example 1 are shown in Table 2.

[0107] Table 2

[0108] Table 2 shows that the acid values ​​of the aqueous polyester dispersions prepared in Examples 1-7 remained essentially unchanged after three weeks of storage at 50°C. Comparative Example 1 showed a significant increase in acid value after prolonged storage. Furthermore, the solution became slightly turbid after one week of storage, and stratified after two weeks. Its storage stability was significantly inferior to that of the Examples. In contrast, the solution state and appearance of Examples 1-7 remained unchanged after three weeks of storage.

[0109] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations of the claims. Various modifications and variations may be made to the above embodiments without departing from the scope of this disclosure. Similarly, the various technical features of the above embodiments may be arbitrarily combined to form additional embodiments of the present invention that may not be explicitly described. Therefore, the above embodiments merely illustrate several implementations of the present invention and do not limit the scope of protection of the patent of this invention.

Claims

1. A method for preparing a hydrolysis-resistant water-based polyester resin, characterized in that: The method comprises: (1) Adding diol, dibasic acid or its ester, organic acid or acid anhydride containing carbon-carbon double bond and catalyst into a reactor to carry out esterification reaction to obtain a prepolymer; (2) after the esterification reaction is completed, subjecting the prepolymer to a condensation reaction; (3) adding an amino acid having a carbon number of 6 to 16 and a catalyst into the reaction system to continue the reaction to obtain the hydrolysis-resistant water-based polyester resin; The molar amount of the organic acid or anhydride containing a carbon-carbon double bond is 10-35% of the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond; The molar amount of the amino acid having 6 to 16 carbon atoms is 5 to 30% of the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond.

2. The preparation method according to claim 1, characterized in that: In step (1), the dibasic acid or its ester is selected from one or more of terephthalic acid or its ester, phthalic acid or its ester, adipic acid and sebacic acid; And / or, in step (1), the diol is selected from one or more of ethylene glycol, neopentyl glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol and 2-methyl-1,3-propanediol; And / or, in step (1), the organic acid or anhydride containing a carbon-carbon double bond is selected from one or more of maleic anhydride, fumaric acid and itaconic acid; And / or, in step (1), the catalyst is selected from one or more of tetrabutyl titanate, tetraethyl titanate, dibutyltin oxide, tin chloride, stannous octoate, dibutyltin maleate and Na, Zn, Mn, Mg, Ca, and Co acetates.

3. The preparation method according to claim 1 or 2, characterized in that: In step (1), the molar ratio of the diol to the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond is (1-2):

1.

4. The preparation method according to claim 1, characterized in that: In step (2), the polycondensation reaction occurs in the presence of an auxiliary agent, and the auxiliary agent is selected from trimethyl phosphate and / or triethyl phosphate.

5. The preparation method according to claim 1, characterized in that: In step (3), the amino acid having 6 to 16 carbon atoms is selected from one or more of 6-aminocaproic acid, 8-aminooctanoic acid, 10-aminodecanoic acid, 12-aminododecanoic acid, 14-aminotetradecanoic acid or 16-aminohexadecanoic acid.

6. The preparation method according to claim 1, characterized in that: The molar amount of the amino acid having 6 to 16 carbon atoms is 5 to 25% of the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond.

7. The preparation method according to claim 1, characterized in that: In step (3), the catalyst is selected from one or more of tetramethylguanidine, 1,8-diazabicycloundec-7-ene, N,N-dimethylcyclohexylamine, dimethylethylene glycolamine and triethylenediamine.

8. A hydrolysis-resistant water-based polyester resin obtained according to the preparation method according to any one of claims 1 to 7.

9. A composition, characterized in that The composition comprises the hydrolysis-resistant water-soluble polyester resin obtained by the preparation method according to any one of claims 1 to 7 or the hydrolysis-resistant water-soluble polyester resin according to claim 8.

10. Use of the hydrolysis-resistant water-based polyester resin obtained by the preparation method according to any one of claims 1 to 7 or the hydrolysis-resistant water-based polyester resin according to claim 8 in water-based coatings or water-based adhesives.

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