An aqueous polyester resin, its preparation method and application

Abstract

The present invention relates to a preparation method of a hydrolysis-resistant polyester resin, which specifically includes: in the presence of a catalyst, a diol, a dicarboxylic acid or its ester, and an organic acid or anhydride containing a carbon-carbon double bond undergo an esterification reaction. After the esterification reaction is completed, a polycondensation reaction is carried out. Subsequently, in the presence of a catalyst, an amino acid with 6 to 16 carbon atoms is added to the reaction system for reaction. The polyester resin prepared by the present invention 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 particularly relates to an aqueous polyester resin, a preparation method thereof, and an application thereof Background Art

[0002] Since the coatings prepared from solvent-based polyester resins contain a large amount of volatile organic compounds (VOCs), when forming a film, their volatilization brings problems such as environmental pollution and waste of resources. Aqueous polyester resins inherit the advantages of oily polyester resins, such as good film fullness, high gloss, weather resistance, light retention, and excellent flexibility, etc., making them widely used in various industries such as automobiles, cans, building materials, and household appliances. However, traditional aqueous polyesters have poor hydrolysis resistance. The ester bonds are easily hydrolyzed and broken to form alcohols and carboxylic acids, and the generated carboxylic acids further catalyze the hydrolysis reaction, accelerating the chain breakage, thus rapidly causing the deterioration of the physical and chemical properties and mechanical properties of the polyester, seriously restricting the environmental protection upgrade and popularization and application of the polyester in aqueous form

[0003] Patent CN104629034A provides a hydrolysis-resistant polyester. This patent finds that when the proportion of primary alcohol-carboxylic acid ester bonds in the ester bonds of the polyester is less than or equal to 75%, the polyester has more excellent hydrolysis resistance than when all the ester bonds of the polyester are formed by primary alcohols and carboxylic acids. A more hydrolysis-resistant polyester is when the proportion of primary alcohol-carboxylic acid ester bonds in the ester bonds of the polyester is less than or equal to 50%. A particularly hydrolysis-resistant polyester is when the proportion of primary alcohol-carboxylic acid ester bonds in the ester bonds of the polyester is less than or equal to 30%. The most hydrolysis-resistant polyester is when the polyester does not contain primary alcohol-carboxylic acid ester bonds. However, this patent has strict requirements on the ratio of primary alcohol to carboxylic acid, which limits the free selection of monomer alcohol components in the polyester to a certain extent

[0004] Patent CN101215730A modifies the polyester by adding an anti-hydrolysis agent - carbodiimide. Although the hydrolysis resistance of the modified polyester obtained by this method is improved, the production cost is relatively high, and at the same time, a large amount of harmful volatile substances are generated during the production process, which has an impact on the environment and the health of personnel

[0005] Patent CN111378102A discloses a hydrolysis-resistant aqueous polyester resin, which is mainly prepared by reacting the following raw materials: organic sulfonate, diol, diester, catalyst, polyhydroxyalkane, dicarboxylic acid, and the dicarboxylic acid at least includes isophthalic acid. By introducing a small amount of sulfonic acid groups, the polyester resin has excellent water dispersion characteristics. The symmetrical polymer molecules formed by the diester (such as dimethyl terephthalate) and the diol (such as neopentyl glycol) have van der Waals hydrogen bond forces, which can reduce the intrusion of water molecules and improve the hydrolysis resistance of the ester bonds. However, the esterification process of gradually increasing the temperature has complex operation steps and high costs, which is not conducive to large-scale production Summary of the Invention

[0006] To solve the above problems, the object of the present invention is to provide an aqueous polyester resin with hydrolysis resistance and good storage stability.

[0007] Solutions for solving the problems

[0008] On the one hand, the present invention provides a method for preparing a hydrolysis-resistant aqueous polyester resin, the method comprising:

[0009] (1) Adding a diol, a dicarboxylic acid or its ester, an organic acid or anhydride containing a carbon-carbon double bond, and a catalyst into a reactor, and carrying out an esterification reaction to obtain a prepolymer;

[0010] (2) After the esterification reaction is completed, carrying out a polycondensation reaction on the prepolymer;

[0011] (3) Adding an amino acid having 6 to 16 carbon atoms and a catalyst into the reaction system and continuing the reaction to obtain the hydrolysis-resistant aqueous polyester resin;

[0012] 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 dicarboxylic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond;

[0013] The molar amount of the amino acid having 6 to 16 carbon atoms is 5-30% of the total molar amount of the dicarboxylic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond.

[0014] Preferably, in step (1), the dicarboxylic 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.

[0015] Preferably, the dicarboxylic 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).

[0016] Preferably, the dicarboxylic acid or its ester is a mixture of terephthalic acid or its ester, phthalic acid or its esterified product, 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).

[0017] Preferably, in step (1), the diol is selected from one or more of ethylene glycol, neopentyl glycol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, and 2-methyl-1,3-propanediol, and preferably one or more of ethylene glycol, neopentyl glycol, and 2-methyl-1,3-propanediol.

[0018] Preferably, the diol is a mixture of ethylene glycol and neopentyl glycol, and the molar ratio of ethylene glycol to neopentyl glycol is (3 - 5):1, preferably 4:1.

[0019] Preferably, the diol is a mixture of 2 - methyl - 1,3 - propanediol and neopentyl glycol, and the molar ratio of 2 - methyl - 1,3 - propanediol to neopentyl glycol is (0.5 - 2):1, preferably 1:1.

[0020] Preferably, in step (1), the organic acid or acid anhydride containing a carbon - carbon double bond is selected from one or more of maleic anhydride, fumaric acid, and itaconic acid, preferably maleic anhydride.

[0021] Preferably, in step (1), the catalyst is selected from one or more of tetrabutyl titanate, tetraethyl titanate, dibutyltin oxide, tin chloride, stannous octanoate, dibutyltin maleate, and Na, Zn, Mn, Mg, Ca acetate salts, and more preferably one or more of Na, Zn acetate salts and tetrabutyl titanate.

[0022] Preferably, in step (1), the ratio of the molar amount of the diol to the total molar amount of the dicarboxylic acid or its ester and the organic acid or acid anhydride containing a carbon - carbon double bond is (1 - 2):1.

[0023] Preferably, in step (1), the reaction system is heated at a rate of 0.4 - 0.6 °C / min for the esterification reaction, and the esterification reaction temperature is controlled at 220 - 240 °C.

[0024] Preferably, in step (1), the esterification reaction is carried out at a stirring rate of 60 - 150 rpm.

[0025] Preferably, in step (1), the pressure of the esterification reaction is controlled at 0.1 MPa.

[0026] 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.

[0027] Preferably, in step (2), the temperature of the polycondensation reaction is controlled at 230 - 250 °C, and the time of the polycondensation reaction is 60 - 150 min.

[0028] Preferably, in step (2), the polycondensation reaction is carried out at a stirring rate of 30 - 100 rpm.

[0029] Preferably, in step (2), the pressure of the polycondensation reaction is controlled below 100 Pa.

[0030] 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.

[0031] Preferably, in step (3), the catalyst is selected from one or more of tetramethylguanidine, 1,8 - diazabicycloundec - 7 - ene, N,N - dimethylcyclohexylamine, dimethylethylene glycol amine, and triethylenediamine.

[0032] Preferably, the molar amount of the amino acid having 6 to 16 carbon atoms is 10 - 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.

[0033] Preferably, in step (3), the temperature of the reaction is controlled to be 80 - 180 °C, and the reaction time is 30 - 100 min.

[0034] Preferably, the reaction in step (3) is carried out at a stirring rate of 60 - 150 rpm.

[0035] Preferably, the method specifically includes: adding diol, dibasic acid or its ester, organic acid or anhydride containing a carbon - carbon double bond, and an organometallic 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, then maintaining the polycondensation temperature at 230 - 250 °C, controlling the vacuum degree of the reaction system to be below 100 Pa, reacting for 60 - 150 min, cooling the reaction system to 80 - 180 °C, adding an amino acid having 6 to 16 carbon atoms and an organic base catalyst, and reacting for 30 - 100 min to obtain the hydrolysis - resistant water - based polyester resin.

[0036] On the one hand, the present invention provides a hydrolysis - resistant water - based polyester resin obtained by the preparation method according to any one of the above.

[0037] On the one hand, the present invention provides a composition, which includes a hydrolysis - resistant polyester resin obtained by the preparation method according to any one of the above or the hydrolysis - resistant water - based polyester resin according to the above.

[0038] On the one hand, the present invention provides the application of the hydrolysis - resistant polyester resin obtained by the preparation method according to any one of the above or the hydrolysis - resistant polyester resin according to the above in a water - based coating or a water - based adhesive.

[0039] Effects of the Invention

[0040] The present invention adopts the melt copolymerization method and Michael addition reaction. By introducing carbon-carbon double bond structures and long side chains with carboxyl groups into the polyester main chain, the resin can be made water-based, and the long side chains can protect the ester groups on the main chain, enabling the polyester to have hydrolysis resistance. This method not only improves the hydrolysis resistance of the water-based resin but also does not change other properties of the resin (such as viscosity, hardness, heat resistance, etc.), ensuring its use effect; the method of the present invention is simple and feasible, does not require special equipment, and reduces production costs. Compared with the methods in the prior art that require special equipment and complex operation processes, the present invention is more practical and economical; the water-based resin of the present invention has excellent hydrolysis resistance and can meet the requirements of some special application scenarios, such as in high-temperature and high-humidity environments or in occasions that require long-term storage, such as food packaging, pharmaceutical packaging, etc. Compared with the water-based resins in the prior art, the water-based resin of the present invention has a broader application prospect. Detailed Embodiments

[0041] To make the technical solutions and beneficial effects of the present invention more obvious and understandable, the following will be described in detail by listing specific embodiments. Unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical and scientific terms in the technical field to which this application belongs.

[0042] For those not specified in the following embodiments regarding specific technologies or conditions, they are generally carried out according to the conventional technologies or conditions described in the literature in this field, or according to the conditions described in the product specifications and recommended by the manufacturer.

[0043] Unless otherwise specified, various starting materials, materials, and reagents are commercially available or synthesized according to known methods.

[0044] Through extensive and in-depth research, the inventor of the present invention designed a resin structure with larger side groups, increased the hydrophobic groups around the ester bonds, thereby reducing the hydrolysis of the ester bonds, and solved the problems of easy hydrolysis and poor storage stability of water-based polyester resins, and synthesized a water-based polyester resin with hydrolysis resistance and good storage stability by the melt polycondensation method.

[0045] On the one hand, the present invention provides a method for preparing a hydrolysis-resistant polyester resin, and the method includes:

[0046] (1) Add diols, dicarboxylic acids or their esters, organic acids or anhydrides containing carbon-carbon double bonds, and catalysts into a reactor, and carry out an esterification reaction to obtain a prepolymer;

[0047] (2) After the esterification reaction is completed, carry out a polycondensation reaction on the prepolymer;

[0048] (3) Add amino acids with 6 to 16 carbon atoms and a catalyst into the reaction system and continue the reaction to obtain the hydrolysis-resistant water-based polyester resin;

[0049] The molar amount of the organic acid or acid anhydride containing a carbon-carbon double bond is 10-35% of the total molar amount of the dicarboxylic acid or its ester and the organic acid or acid anhydride containing a carbon-carbon double bond;

[0050] The molar amount of the amino acid having 6-16 carbon atoms is 5-30% of the total molar amount of the dicarboxylic acid or its ester and the organic acid or acid anhydride containing a carbon-carbon double bond.

[0051] The inventors of the present invention found through research that the long-chain amino acid has 6-16 carbon atoms. If the number of carbon atoms is less than 6, the side chain has a poor protective effect on the main-chain ester group, and the hydrolysis resistance of the resin is poor; if the number of carbon atoms is more than 16, it affects the water solubility of the resin, making it difficult to waterize the resin.

[0052] In some embodiments, in step (1), the dicarboxylic 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.

[0053] In some embodiments, the dicarboxylic 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), such as 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.

[0054] In some 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).

[0055] In some embodiments, the molar ratio of terephthalic acid or its ester, phthalic acid or its ester, and sebacic acid is 1:1:(0.5-1).

[0056] In certain embodiments, the dibasic acid or its ester is a mixture of terephthalic acid or its ester, phthalic acid or its esterified product, 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 to 2), such as 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.

[0057] 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 to 1).

[0058] In certain embodiments, in step (1), the diol is selected from one or more of ethylene glycol, neopentyl glycol, 1,2 - propanediol, 1,4 - butanediol, 1,6 - hexanediol, and 2 - methyl - 1,3 - propanediol.

[0059] In certain embodiments, the diol is selected from one or more of ethylene glycol, neopentyl glycol, and 2 - methyl - 1,3 - propanediol.

[0060] In certain embodiments, the diol is a mixture of ethylene glycol and neopentyl glycol, and the molar ratio of ethylene glycol to neopentyl glycol is (3 to 5):1, such as 3.5:1, 4:1, 4.5:1, 5:1, etc.

[0061] In certain embodiments, the molar ratio of ethylene glycol to neopentyl glycol is 4:1.

[0062] In certain embodiments, the diol is a mixture of 2 - methyl - 1,3 - propanediol and neopentyl glycol, and the molar ratio of 2 - methyl - 1,3 - propanediol to neopentyl glycol is (0.5 to 2):1, such as 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.

[0063] In certain embodiments, the molar ratio of 2 - methyl - 1,3 - propanediol to neopentyl glycol is 1:1.

[0064] In certain embodiments, in step (1), the organic acid or acid anhydride containing a carbon - carbon double bond is selected from one or more of maleic anhydride, fumaric acid, and itaconic acid.

[0065] In some embodiments, the organic acid or anhydride containing a carbon-carbon double bond is selected from maleic anhydride.

[0066] In some embodiments, in step (1), the catalyst is an organometallic catalyst.

[0067] In some 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 Na, Zn, Mn, Mg, Ca, Co acetates.

[0068] In some embodiments, in step (1), the catalyst is selected from one or more of Na, Zn acetates, and tetrabutyl titanate.

[0069] In some embodiments, in step (1), the catalyst is a mixture selected from Na, Zn acetates, and tetrabutyl titanate.

[0070] In some embodiments, the amount of the catalyst is 250 - 400 ppm of the total mass of the diol, the dicarboxylic acid or its ester, and the organic acid or anhydride containing a carbon-carbon double bond, such as 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.

[0071] In some embodiments, the amount of the catalyst is 300 - 400 ppm of the total mass of the diol, the dicarboxylic acid or its ester, and the organic acid or anhydride containing a carbon-carbon double bond.

[0072] In some embodiments, in step (1), the molar ratio of the diol to the total molar amount of the dicarboxylic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond is (1 - 2):1, such as 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, etc.

[0073] In some embodiments, in step (1), the molar ratio of the diol to the total molar amount of the dicarboxylic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond is (1.2 - 1.8):1.

[0074] In some 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 dicarboxylic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond.

[0075] In some 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 dicarboxylic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond.

[0076] In some 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 at 220 - 240 °C (such as 225 °C, 230 °C, 235 °C, 240 °C, etc.).

[0077] In some embodiments, in step (1), the reaction system is heated at a rate of 0.5 °C / min to carry out the esterification reaction.

[0078] In some embodiments, in step (1), the esterification reaction is carried out at a stirring rate of 60 - 150 rpm (such as 70 rpm, 80 rpm, 90 rpm, 100 rpm, 110 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm, etc.).

[0079] In some embodiments, in step (1), the pressure of the esterification reaction is controlled at 0.1 MPa.

[0080] In some embodiments, step (1) is specifically: adding a diol, a dicarboxylic acid or its ester, an organic acid or anhydride containing a carbon-carbon double bond, and a catalyst into a reactor, heating to 100 - 150 °C for the first time, stirring, and heating to 220 - 240 °C at a rate of 0.4 - 0.6 °C / min for the second time to carry out the esterification reaction, and ending the esterification reaction when the amount of the esterification distillate reaches more than 90% of the theoretical value.

[0081] In some 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.

[0082] In some embodiments, in step (2), the dosage of the auxiliary agent is 100 to 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, such as 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.

[0083] In some embodiments, in step (2), the temperature of the polycondensation reaction is controlled to be 230 to 250 °C, and the time of the polycondensation reaction is 60 to 150 min.

[0084] In some embodiments, in step (2), the polycondensation reaction is carried out at a stirring rate of 30 to 100 rpm (such as 40 rpm, 50 rpm, 60 rpm, 70 rpm, 80 rpm, 90 rpm, 100 rpm, etc.).

[0085] In some embodiments, in step (2), the pressure of the polycondensation reaction is controlled to be below 100 Pa.

[0086] In some embodiments, 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.

[0087] In some 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.

[0088] In some embodiments, in step (3), the catalyst is an organic base catalyst.

[0089] In some embodiments, in step (3), the catalyst is selected from one or more of tetramethylguanidine, 1,8 - diazabicyclo[5.4.0]undec - 7 - ene, N,N - dimethylcyclohexylamine, dimethylethylene glycol amine, and triethylenediamine.

[0090] In some embodiments, in step (3), the catalyst is selected from tetramethylguanidine.

[0091] In some embodiments, in step (3), the dosage of the catalyst 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, such as 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.

[0092] In some embodiments, in step (3), the dosage of the catalyst 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.

[0093] In some 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 5-30% molar amount 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%, since the introduction of the long-chain amino acid depends 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 will cause easy cross-linking during the resin synthesis process.

[0094] In some embodiments, the molar amount of the amino acid having 6 to 16 carbon atoms is 5-25% of the total molar amount of the dibasic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond.

[0095] In some embodiments, in step (3), the temperature of the reaction is controlled to be 80-180 °C (such as 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, etc.), and the time of the reaction is 30-100 min (such as 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, etc.).

[0096] In some embodiments, the reaction in step (3) is carried out at a stirring rate of 60 to 150 rpm (such as 70 rpm, 80 rpm, 90 rpm, 100 rpm, 110 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm, etc.).

[0097] In some embodiments, the method specifically includes: adding a diol, a dicarboxylic acid or its ester, an organic acid or anhydride containing a carbon-carbon double bond, and an organometallic catalyst into a reactor, heating to 220 to 240 °C for an esterification reaction. When the amount of the esterification distillate reaches more than 90% of the theoretical value, cooling to 180 to 220 °C, adding an auxiliary agent, maintaining the polycondensation temperature at 230 to 250 °C, controlling the vacuum degree of the reaction system below 100 Pa, reacting for 60 to 150 min, cooling the reaction system to 80 to 180 °C, adding an amino acid with 6 to 16 carbon atoms and an organic base catalyst, and reacting for 30 to 100 min to obtain the hydrolysis-resistant polyester resin.

[0098] A new method for improving the hydrolysis resistance of a waterborne resin proposed by the present invention can effectively improve the hydrolysis resistance of the resin and ensure the use effect of the resin. Secondly, the waterborne polyester resin provided by the present invention can reduce the performance degradation of the waterborne resin caused by hydrolysis reaction during use, extend its service life, and meet the market demand for high-performance waterborne resins. Finally, the operation of this technical solution is simple, the cost is low, it is conducive to large-scale production, and has broad market application prospects.

[0099] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific conditions noted in the following embodiments are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are weight percentages and weight parts. Example 1

[0100] 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 were added into a 2 L stainless steel reactor. 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate and 0.16 g of zinc acetate as catalysts were added simultaneously. The system pressure was maintained at 0.1 Mpa, and the reaction temperature was raised to 120 °C. Stirring was started, and the stirring rate was set at 100 rpm. Then, programmed heating was carried out, and the heating rate was set at 0.5 °C / min. When the temperature reached 235 °C, the temperature was maintained until the by-product output reached more than 90% of the theoretical value to end the esterification; the system was cooled to 200 °C, 0.2 g of trimethyl phosphate was added, and after stirring for 30 min, polycondensation was started. The stirring rate was 60 rpm, the polycondensation temperature was 240 °C, the vacuum degree was 100 Pa, and the polycondensation time was 120 min; then the system was cooled to 150 °C, 163.24 g of 12-aminododecanoic acid and 0.16 g of tetramethylguanidine were added, the stirring rate was 100 rpm, and after stirring for 60 min, the product could be taken out of the reactor. Example 2

[0101] 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 were added into a 2 L stainless steel reactor. 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate and 0.16 g of zinc acetate as catalysts were added simultaneously. The system pressure was maintained at 0.1 Mpa, and the reaction temperature was raised to 120 °C. Stirring was started, and the stirring rate was set at 100 rpm. Then, programmed heating was carried out, and the heating rate was set at 0.5 °C / min. When the temperature reached 235 °C, the temperature was maintained until the by-product output reached more than 90% of the theoretical value to end the esterification; the system was cooled to 200 °C, 0.2 g of trimethyl phosphate was added, and after stirring for 30 min, polycondensation was started. The stirring rate was 60 rpm, the polycondensation temperature was 240 °C, the vacuum degree was 100 Pa, and the polycondensation time was 120 min; then the system was cooled to 150 °C, 143.89 g of 10-aminodecanoic acid and 0.16 g of tetramethylguanidine were added, the stirring rate was 100 rpm, and after stirring for 60 min, the product could be taken out of the reactor. Example 3

[0102] 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 were added into a 2 L stainless steel reactor. 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate and 0.16 g of zinc acetate as catalysts were added simultaneously. The system pressure was maintained at 0.1 Mpa, and the reaction temperature was raised to 120 °C. Stirring was started, and the stirring rate was set at 100 rpm. Then, programmed heating was carried out with a heating rate of 0.5 °C / min. When the temperature reached 235 °C, the temperature was maintained until the by-product output reached more than 90% of the theoretical value to end the esterification. The system was cooled to 200 °C, 0.2 g of trimethyl phosphate was added, and after stirring for 30 min, polycondensation was started. The stirring rate was 60 rpm, the polycondensation temperature was 240 °C, the vacuum degree was 100 Pa, and the polycondensation time was 120 min. Subsequently, the system was cooled to 150 °C, 163.24 g of 16-aminohexadecanoic acid and 0.16 g of tetramethylguanidine were added, the stirring rate was 100 rpm, and stirring for 60 min was carried out before discharging from the reactor. Example 4

[0103] 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 were added into a 2 L stainless steel reactor. 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate and 0.16 g of zinc acetate as catalysts were added simultaneously. The system pressure was maintained at 0.1 Mpa, and the reaction temperature was raised to 120 °C. Stirring was started, and the stirring rate was set at 100 rpm. Then, programmed heating was carried out with a heating rate of 0.5 °C / min. When the temperature reached 235 °C, the temperature was maintained until the by-product output reached more than 90% of the theoretical value to end the esterification. The system was cooled to 200 °C, 0.2 g of trimethyl phosphate was added, and after stirring for 30 min, polycondensation was started. The stirring rate was 60 rpm, the polycondensation temperature was 240 °C, the vacuum degree was 100 Pa, and the polycondensation time was 120 min. Subsequently, the system was cooled to 150 °C, 100.64 g of 16-aminohexadecanoic acid, 93.93 g of 14-aminotetradecanoic acid and 0.16 g of tetramethylguanidine were added, the stirring rate was 100 rpm, and stirring for 60 min was carried out before discharging from the reactor. Example 5

[0104] 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 were added into a 2 L stainless steel reactor. 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate and 0.16 g of zinc acetate as catalysts were added simultaneously. 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 at 100 rpm. Then, programmed heating was carried out with a heating rate of 0.5 °C / min. When the temperature reached 235 °C, the temperature was maintained until the by-product yield reached more than 90% of the theoretical value to end the esterification; the system was cooled to 200 °C, 0.2 g of trimethyl phosphate was added, and after stirring for 30 min, polycondensation was started with a stirring rate of 60 rpm, a polycondensation temperature of 240 °C, a vacuum degree of 100 Pa, and a polycondensation time of 120 min; subsequently, the system was cooled to 150 °C, 85.72 g of 12-aminododecanoic acid and 0.16 g of tetramethylguanidine were added, and after stirring at a rate of 100 rpm for 60 min, the product could be discharged from the reactor. Example 6

[0105] 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 were added into a 2 L stainless steel reactor. 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate and 0.16 g of zinc acetate as catalysts were added simultaneously. 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 at 100 rpm. Then, programmed heating was carried out with a heating rate of 0.5 °C / min. When the temperature reached 235 °C, the temperature was maintained until the by-product yield reached more than 90% of the theoretical value to end the esterification; the system was cooled to 200 °C, 0.2 g of trimethyl phosphate was added, and after stirring for 30 min, polycondensation was started with a stirring rate of 60 rpm, a polycondensation temperature of 240 °C, a vacuum degree of 100 Pa, and a polycondensation time of 120 min; subsequently, the system was cooled to 150 °C, 231.17 g of 12-aminododecanoic acid and 0.16 g of tetramethylguanidine were added, and after stirring at a rate of 100 rpm for 30 min, the product could be discharged from the reactor. Example 7

[0106] 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, and 345.09 g of neopentyl glycol were added to a 2 L stainless steel reactor. 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate, and 0.16 g of zinc acetate as catalysts were added simultaneously. The system pressure was maintained at 0.1 Mpa, and the reaction temperature was raised to 120 °C. Stirring was started, and the stirring rate was set at 100 rpm. Then, programmed temperature increase was carried out, with the heating rate set at 0.5 °C / min. When the temperature reached 235 °C, the temperature was maintained until the by-product output reached more than 90% of the theoretical value, and then the esterification was ended. The system was cooled to 200 °C, 0.2 g of trimethyl phosphate was added, and after stirring for 30 min, polycondensation was started. The stirring rate was 60 rpm, the polycondensation temperature was 240 °C, the vacuum degree was 100 Pa, and the polycondensation time was 120 min. Subsequently, the system was cooled to 150 °C, 231.17 g of 12-aminododecanoic acid and 0.16 g of tetramethylguanidine were added, the stirring rate was 100 rpm, and stirring for 60 min was carried out before discharging from the reactor.

[0107] Comparative Example 1

[0108] On the basis of Example 1, the dosages of maleic anhydride and 12-aminododecanoic acid were reduced to 1 / 5 of the dosages in Example 1, and the rest remained unchanged.

[0109] Comparative Example 2

[0110] On the basis of Example 1, the dosages of maleic anhydride and 12-aminododecanoic acid were increased to 2.5 times the dosages in Example 1, and the polycondensation time was reduced from 120 min to 60 min, while the rest remained unchanged.

[0111] The waterborne polyester resins prepared in Examples 1 - 7 and Comparative Examples 1 - 2 were subjected to performance characterization.

[0112] Glass transition temperature (Tg): It was measured using a TA Q20 differential scanning calorimeter. During the test, the flow rate of nitrogen atmosphere was 20 mL / min, and 5 mg of the 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, held for 2 min in this state to eliminate the thermal history, then cooled to 30 °C at a cooling rate of 10 °C / min. Subsequently, the sample underwent a second heating process, rising from 30 °C to 180 °C at a heating rate of 10 °C / min, and the glass transition temperature of the sample was obtained from the second heating.

[0113] Intrinsic viscosity test (IV): It was measured using an Ubbelohde viscometer with o-chlorophenol as the solvent at a temperature of 35 °C. The calculation formula for the intrinsic viscosity is:

[0114]

[0115] In the formula: η: intrinsic viscosity, mL / g; : specific viscosity; : viscosity ratio; c: polymer concentration, mol / L; t: sample efflux time, s; t0: blank sample efflux time, s.

[0116] The acid value test refers to the national standard GB / T 6743-2008 "Determination of Part Acid Value and Total Acid Value of Polyester Resins for Plastics, Resin Bases for Paints and Varnishes".

[0117] Preparation method of the aqueous polyester dispersion: Take 30 g of the polyester prepared above, add 70 g of deionized water, add 5 g of N,N-dimethylethanolamine and stir evenly to obtain an aqueous polyester dispersion with a solid content of 30%.

[0118] The test results of the intrinsic viscosity, Tg and acid value of the aqueous polyester resins prepared in Examples 1-7 and Comparative Examples 1-2 are shown in Table 1.

[0119] Table 1

[0120]

[0121] In Comparative Example 2, due to the large addition amount of maleic anhydride, the system is prone to crosslinking during the polycondensation process, so it is difficult to obtain a sample with a large intrinsic viscosity.

[0122] The above samples (except Comparative Example 2) were dissolved, and the change of acid value during their storage was monitored. Polyester hydrolysis will produce acid and alcohol, so monitoring the change of its acid value can obtain its hydrolysis resistance. The storage condition is a constant temperature of 50°C. The hydrolysis resistance test results of the aqueous polyester resins prepared in Examples 1-7 and Comparative Example 1 are shown in Table 2.

[0123] Table 2

[0124]

[0125] It can be seen from Table 2 that the acid value of the aqueous polyester dispersions prepared in Examples 1-7 is basically unchanged after being stored for three weeks at 50°C. After long-term storage in Comparative Example 1, the acid value increased significantly, and after being stored for one week, the solution showed slight turbidity, and after two weeks, the solution had already stratified, and its storage stability was significantly worse than that of the examples. In contrast, after being stored for three weeks in Examples 1-7, the solution state and appearance did not change significantly.

[0126] It should be understood that the above embodiments are all exemplary and do not cover all possible implementation manners included in the claims. Without departing from the scope of the present disclosure, various deformations and changes can also be made on the basis of the above embodiments. Similarly, various technical features of the above embodiments can also be arbitrarily combined to form additional embodiments of the present invention that may not be explicitly described. Therefore, the above embodiments only represent several implementation manners of the present invention and do not limit the protection scope of the present invention patent.

Claims

1. A preparation method of a hydrolysis-resistant waterborne polyester resin, characterized in that, The method includes: (1) adding a diol, a dicarboxylic acid or its ester, an organic acid or anhydride containing a carbon-carbon double bond, and a catalyst into a reactor to carry out an esterification reaction to obtain a prepolymer; (2) after the esterification reaction ends, carrying out a polycondensation reaction on the prepolymer; (3) adding an amino acid with 6 to 16 carbon atoms and a catalyst into the reaction system and continuing the reaction to obtain the hydrolysis-resistant waterborne 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 dicarboxylic 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 dicarboxylic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond; 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; The amino acid with 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; 2. The preparation method according to claim 1, characterized in that, In step (1), the dicarboxylic 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-propanediol, 1,4-butanediol, 1,6-hexanediol and 2-methyl-1,3-propanediol; And / or, in step (1), the catalyst is selected from one or more of tetrabutyl titanate, tetraethyl titanate, dibutyltin oxide, stannous chloride, stannous octoate, dibutyltin maleate and Na, Zn, Mn, Mg, Ca acetate; 3. The preparation method according to claim 1 or 2, characterized in that, In step (1), the ratio of the molar amount of the diol to the total molar amount of the dicarboxylic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond is (1 to 2):

1.

4. The preparation method according to claim 1, wherein 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, The molar amount of the amino acid with 6 to 16 carbon atoms is 5 to 25% of the total molar amount of the dicarboxylic acid or its ester and the organic acid or anhydride containing a carbon-carbon double bond; 6. 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-diazabicyclo[5.4.0]undec-7-ene, N,N-dimethylcyclohexylamine, dimethylethylene glycolamine and triethylenediamine; 7. A hydrolysis-resistant waterborne polyester resin obtained by the preparation method according to any one of claims 1 to 6.

8. A composition, characterized in that, The composition includes the hydrolysis-resistant waterborne polyester resin obtained by the preparation method according to any one of claims 1 to 6 or the hydrolysis-resistant waterborne polyester resin according to claim 7.

9. Application of the hydrolysis-resistant waterborne polyester resin obtained by the preparation method according to any one of claims 1 to 6 or the hydrolysis-resistant waterborne polyester resin according to claim 7 in a waterborne coating or a waterborne adhesive.

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