Aqueous polyester and process for its preparation and use

Abstract

The present application relates to a kind of aqueous polyester and its preparation method and application, the raw material of the aqueous polyester includes binary acid, binary alcohol, organic sulfonate and the compound as shown in formula (I), wherein, R1Selected from H or C 1～10 Alkyl;R2Selected from C 3～10 Alkyl;R3, R4 each independently selected from H or C 1～6 Alkyl.The aqueous polyester provided by the present application is not prone to hydrolysis, has excellent hydrolysis resistance, good long-term storage stability;And the aqueous polyester of the present application is synthesized by one-step method, has the advantages of simple synthesis route, easy operation etc.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to an aqueous polyester, its preparation method, and its application. Background Technology

[0002] Waterborne polyester (WPE) is a new type of waterborne resin. It is usually formed by copolymerizing ionic structural units into polyester matrix segments with excellent thermodynamic properties to form ionic copolyesters. Currently, the mainstream waterborne polyesters are roughly divided into two categories: carboxylate waterborne polyesters and sulfonate waterborne polyesters.

[0003] For aqueous polyesters containing carboxylates, they mainly dissolve in water by neutralizing carboxyl groups with amines to form salts. However, the carboxyl groups in the chain segments are prone to catalyzing the hydrolysis and breakage of ester bonds, which damages the properties of the polyester. For aqueous polyesters containing sulfonates, they are added to the polyester system to make the polyester water-soluble by introducing sulfonates. However, sulfonates have poor compatibility with polyesters. After long-term storage, the solution is prone to flocculation and stratification. At the same time, during long-term storage, the ester bonds will also undergo some hydrolysis, and the performance will gradually decline.

[0004] Patent CN104629034 B improves the hydrolysis resistance of polyester samples by introducing secondary and tertiary alcohol hydroxyl groups into the polyester system to form a hydrophobic environment around the ester bonds. However, due to steric hindrance, the secondary and tertiary hydroxyl groups are difficult to react with acids, leading to numerous side reactions during synthesis and affecting resin performance. Patent CN103214663B improves sample solubility by screening raw materials to increase sample polarity. However, this method alone does not address the underlying problem of high acid values ​​and lacks sufficient storage stability. Patent CN105694014... Patent A synthesizes a hyperbranched waterborne resin by replacing trimellitic anhydride with dimethylolpropionic acid. This method utilizes steric hindrance to weaken the effect of carboxyl groups on ester bond hydrolysis while introducing a large number of hydroxyl groups, thus synthesizing a hydrolysis-resistant waterborne polyester. However, the samples synthesized by this method generally have a low Tg, and for the resin itself, the presence of carboxylic acid only slows down the hydrolysis rate, failing to fundamentally solve the hydrolysis resistance problem. Patent CN111378102 B introduces sulfonates and neopentyl glycol into the polyester system. The symmetrical polymer molecules have van der Waals hydrogen bonds, which can reduce the intrusion of water molecules and improve the hydrolysis resistance of ester bonds. However, the molar proportion of sulfonates is still relatively large, so under long-term storage conditions, flocculation due to incompatibility between sulfonates and polyester will occur.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a waterborne polyester with excellent hydrolysis resistance and good stability.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] The first aspect of this invention provides an aqueous polyester, wherein the raw materials for preparing the aqueous polyester include a diacid, a diol, an organic sulfonate, and a compound as shown in formula (I).

[0009]

[0010] R1 is selected from H or C. 1～10 alkyl;

[0011] R2 is selected from C 3～10 alkyl;

[0012] R3 and R4 are each independently selected from H or C. 1～6 alkyl.

[0013] In another preferred embodiment, R1 is selected from H or C. 1～6 Alkyl group; preferably, R1 is selected from H or C. 1～4 Alkyl; more preferably, R1 is selected from H, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl.

[0014] Preferably, R2 is selected from C 3～6 Alkyl group; more preferably, R2 is selected from C10. 3～5 Alkyl; more preferably, R2 is selected from one of n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tert-pentyl, and neopentyl.

[0015] Preferably, R3 and R4 are each independently selected from H or C. 1～4 Alkyl group; more preferably, R3 and R4 are each independently selected from H or C. 1～3 Alkyl; more preferably, R3 and R4 are each independently selected from H, methyl, and ethyl.

[0016] Preferably, the compound represented by formula (I) is selected from one or more of dibutylmalonate, 2-butyl-2-ethylmalonic acid, diethyl isopentylmalonate, dimethyl butylmalonate, di-n-propylmalonate, and diisobutylmalonate.

[0017] Preferably, the molar amount of the compound represented by formula (I) accounts for 20-50% of the total molar amount of the dicarboxylic acid, the organic sulfonate, and the compound represented by formula (I); more preferably 25-50%; further preferably 30-50%; even more preferably 32-50%, and specifically preferably 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, etc.

[0018] Preferably, the organic sulfonate is selected from one or more of sodium dimethyl isophthalate-5-sulfonate, sodium dimethyl isophthalate-5-sulfonate, sodium diethyl hydroxyisophthalate-5-sulfonate, and sodium terephthalate-5-sulfonate, and more preferably sodium dimethyl isophthalate-5-sulfonate.

[0019] Preferably, the molar amount of the organic sulfonate accounts for 2 to 4% of the total molar amount of the dicarboxylic acid, the organic sulfonate, and the compound represented by formula (I); more preferably 2 to 3.5%, and more specifically 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, etc.

[0020] Preferably, the number of carbon atoms in the main chain of the diol is odd; more preferably, the number of carbon atoms in the main chain of the diol is selected from odd numbers from 3 to 25, and more preferably 3, 5, 7 or 9; even more preferably, the diol is selected from one or more of neopentyl glycol, 2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 1,2-propanediol and 2,2,4-trimethyl-1,3-pentanediol.

[0021] Preferably, the dicarboxylic acid is selected from aromatic dicarboxylic acids and / or aliphatic dicarboxylic acids; more preferably, the aromatic dicarboxylic acid is selected from isophthalic acid and / or terephthalic acid.

[0022] More preferably, the aliphatic dicarboxylic acid has 3 to 10 carbon atoms; even more preferably, it has 3 to 6 carbon atoms; and still more preferably, the aliphatic dicarboxylic acid is selected from succinic acid and / or dicolic acid.

[0023] Preferably, the total molar ratio of the diol to the dicarboxylic acid, the organic sulfonate, and the compound represented by formula (I) is (1.5–2.0):1; more preferably (1.5–1.9):1, and more specifically 1.55:1, 1.6:1, 1.65:1, 1.7:1, 1.75:1, 1.8:1, 1.85:1, etc.

[0024] A second aspect of the present invention provides a method for preparing the aqueous polyester according to any one of the above claims, wherein the preparation method comprises:

[0025] (1) Add a dicarboxylic acid, a diol, an organic sulfonate, a compound as shown in formula (I) and a catalyst into a reactor, heat the reaction system to carry out an esterification reaction, and obtain an intermediate product.

[0026] (2) After the esterification reaction is completed, the intermediate product is subjected to polycondensation reaction to obtain the waterborne polyester.

[0027] Preferably, in step (1), the heating includes a first heating and a second heating; preferably, the first heating is controlled to 100-140°C; more preferably, it is 110-130°C, and more specifically, it is 115°C, 120°C, 125°C, 130°C, etc.

[0028] Preferably, the second temperature rise is controlled to 220-240°C; more preferably 225-235°C, and more specifically 226°C, 227°C, 228°C, 229°C, 230°C, 231°C, 232°C, 233°C, 234°C, 235°C, etc.

[0029] Preferably, the rate of the second heating is controlled to be 0.4–0.6 °C / min; more preferably 0.45–0.55 °C / min, and more specifically 0.46 °C / min, 0.47 °C / min, 0.48 °C / min, 0.49 °C / min, 0.50 °C / min, 0.51 °C / min, 0.52 °C / min, 0.53 °C / min, 0.54 °C / min, etc.

[0030] Preferably, in step (1), after the first heating is completed, the reaction system is stirred; more preferably, the stirring rate is controlled to be 60-100 rpm; even more preferably, it is 60-80 rpm, and more specifically, it is 62 rpm, 64 rpm, 66 rpm, 68 rpm, 70 rpm, 72 rpm, 74 rpm, 76 rpm, 78 rpm, etc.

[0031] Preferably, in step (1), the catalyst is selected from one or more of Na, Zn, Mn, Mg, Ca, Co acetate and titanate, and more preferably one or more of Na, Zn acetate and tetrabutyl titanate.

[0032] Preferably, in step (1), the pressure of the esterification reaction is controlled to be atmospheric pressure.

[0033] Preferably, in step (1), the esterification reaction is carried out under a nitrogen atmosphere.

[0034] Preferably, the endpoint of the esterification reaction is when the amount of byproducts collected is greater than 90% of the theoretical value.

[0035] Preferably, in step (2), the temperature of the polycondensation reaction is controlled to be 220-300℃; more preferably 220-260℃, and more specifically 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, and 260℃.

[0036] Preferably, in step (2), the polycondensation reaction is carried out at a stirring rate of 40 to 100 rpm; more preferably, in step (2), the polycondensation reaction is carried out at a stirring rate of 40 to 80 rpm.

[0037] Preferably, in step (2), the pressure of the polycondensation reaction is controlled to be below 100 Pa.

[0038] Preferably, in step (2), the polycondensation reaction occurs in the presence of a stabilizer selected from one or more of phosphoric acid, phosphate esters, phosphorous acid, and phosphate esters, more preferably phosphate esters, and even more preferably trimethyl phosphate.

[0039] A third aspect of the present invention provides a composition comprising the aqueous polyester described in any one of the preceding claims.

[0040] A fourth aspect of the present invention provides the use of the waterborne polyester described in any of the preceding claims in waterborne coatings.

[0041] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0042] This invention introduces a compound as shown in formula (I) into a polyester system, thereby making the ester bonds in the polyester less prone to hydrolysis under the protection of the side chain groups of the compound as shown in formula (I). By optimizing the composition of the entire polyester system, the waterborne polyester provided by this invention has excellent hydrolysis resistance and stability. Furthermore, this invention synthesizes the waterborne polyester in one step, which has the advantages of simple synthesis route and easy operation. Detailed Implementation

[0043] To make the technical solution and beneficial effects of the present invention more apparent and understandable, a detailed description is provided below by listing specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Any product identical or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention. Unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application pertains.

[0044] Unless otherwise specified, the techniques or conditions described in the following embodiments are generally performed in accordance with conventional techniques or conditions described in the literature in this field, or in accordance with the product manual and the manufacturer's recommendations.

[0045] Unless otherwise specified, all starting materials, ingredients and reagents are commercially available or synthesized according to known methods.

[0046] The first aspect of this invention provides an aqueous polyester, wherein the raw materials for preparing the aqueous polyester include a diacid, a diol, an organic sulfonate, and a compound as shown in formula (I).

[0047]

[0048] R1 is selected from H or C. 1～10 alkyl;

[0049] R2 is selected from C 3～10 alkyl;

[0050] R3 and R4 are each independently selected from H or C. 1～6 alkyl.

[0051] In some implementations, R1 is selected from H or C. 1～6 alkyl.

[0052] In some implementations, R1 is selected from H or C. 1～4 alkyl.

[0053] In some embodiments, R1 is selected from H, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl.

[0054] In a specific and preferred embodiment, R1 is selected from H, ethyl, n-propyl, n-butyl, and isobutyl.

[0055] In some implementations, R2 is selected from C 3～6 alkyl.

[0056] In some implementations, R2 is selected from C 3～5 alkyl.

[0057] In some embodiments, R2 is selected from one of n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tert-pentyl, and neopentyl.

[0058] In a specific and preferred embodiment, R2 is selected from one of n-propyl, n-butyl, isobutyl, and isopentyl.

[0059] In some implementations, R3 is selected from H or C. 1～4 alkyl.

[0060] In some implementations, R3 is selected from H or C. 1～3 alkyl.

[0061] In some embodiments, R3 is selected from H, methyl, and ethyl.

[0062] In some implementations, R4 is selected from H or C. 1～4 alkyl.

[0063] In some implementations, R4 is selected from H or C. 1～3 alkyl.

[0064] In some embodiments, R4 is selected from H, methyl, and ethyl.

[0065] In some embodiments, the compound represented by formula (I) is selected from one or more of dibutylmalonate, 2-butyl-2-ethylmalonic acid, diethyl isopentylmalonate, dimethyl butylmalonate, di-n-propylmalonate, and diisobutylmalonate.

[0066] In some embodiments, the molar amount of the compound represented by formula (I) accounts for 20 to 50% of the total molar amount of the dicarboxylic acid, the organic sulfonate, and the compound represented by formula (I).

[0067] In some embodiments, the molar amount of the compound represented by formula (I) accounts for 25 to 50% of the total molar amount of the dicarboxylic acid, the organic sulfonate, and the compound represented by formula (I).

[0068] In some embodiments, the molar amount of the compound represented by formula (I) accounts for 30 to 50% of the total molar amount of the dicarboxylic acid, the organic sulfonate, and the compound represented by formula (I).

[0069] In some embodiments, the molar amount of the compound represented by formula (I) accounts for 32% to 50% of the total molar amount of the diacid, the organic sulfonate, and the compound represented by formula (I), specifically preferably 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, etc. Under suitable molar ratios of the compound represented by formula (I) and the total molar amount of the diacid, the organic sulfonate, and the compound represented by formula (I), the hydrolysis resistance of waterborne polyesters can be better improved, as can the storage stability of waterborne polyesters at room temperature, and the cost is low.

[0070] In some embodiments, the organic sulfonate is selected from one or more of sodium dimethyl isophthalate-5-sulfonate, sodium isophthalate-5-sulfonate, sodium dihydroxyethyl isophthalate-5-sulfonate, and sodium terephthalate-5-sulfonate.

[0071] In a specific and preferred embodiment, the organic sulfonate is selected from sodium dimethyl isophthalate-5-sulfonate.

[0072] In some embodiments, the molar amount of the organic sulfonate accounts for 2 to 4% of the total molar amount of the dicarboxylic acid, the organic sulfonate, and the compound represented by formula (I).

[0073] In some embodiments, the molar amount of the organic sulfonate accounts for 2-3.5% of the total molar amount of the diacid, the organic sulfonate, and the compound represented by formula (I), specifically preferably 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, etc. Under suitable molar ratios of the organic sulfonate and the diacid, the organic sulfonate, and the compound represented by formula (I), the hydrolysis resistance of waterborne polyesters can be improved, as can the storage stability of waterborne polyesters at room temperature, and the cost is low.

[0074] In some embodiments, the number of carbon atoms in the diol backbone is odd.

[0075] In some embodiments, the number of carbon atoms in the diol backbone is selected from an odd number of natural numbers from 3 to 25.

[0076] In some embodiments, the number of carbon atoms in the diol backbone is 3, 5, 7 or 9.

[0077] In a specific and preferred embodiment, the diol is selected from one or more of neopentyl glycol, 2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 1,2-propanediol, and 2,2,4-trimethyl-1,3-pentanediol. This invention selects diols with an odd number of carbon atoms in the main chain and uses them in combination with other components to reduce the crystallinity of the polyester. Under this structure, this invention can perform hydrolysis with auxiliaries using only a smaller amount of organic sulfonates, thus better improving the solubility and hydrolysis resistance of waterborne polyesters in water, and consequently improving the storage stability of waterborne polyesters at room temperature.

[0078] In some embodiments, the dicarboxylic acid is selected from aromatic dicarboxylic acids and / or aliphatic dicarboxylic acids.

[0079] In a specific and preferred embodiment, the aromatic dicarboxylic acid is selected from isophthalic acid and / or terephthalic acid.

[0080] In another specific and preferred embodiment, the aliphatic dicarboxylic acid has 3 to 10 carbon atoms.

[0081] In some embodiments, the aliphatic dicarboxylic acid has 3 to 6 carbon atoms.

[0082] In some embodiments, the aliphatic dicarboxylic acid is selected from succinic acid and / or succinic acid.

[0083] In some embodiments, the total molar ratio of the diol to the dicarboxylic acid, the organic sulfonate, and the compound represented by formula (I) is (1.5 to 2.0):1.

[0084] In a specific and preferred embodiment, the total molar ratio of the diol to the dicarboxylic acid, the organic sulfonate, and the compound represented by formula (I) is (1.5 to 1.9):1, and is preferably 1.55:1, 1.6:1, 1.65:1, 1.7:1, 1.75:1, 1.8:1, 1.85:1, etc.

[0085] A second aspect of the present invention provides a method for preparing the aqueous polyester according to any one of the above claims, wherein the preparation method comprises:

[0086] (1) Add a dicarboxylic acid, a diol, an organic sulfonate, a compound as shown in formula (I) and a catalyst into a reactor, heat the reaction system to carry out an esterification reaction, and obtain an intermediate product.

[0087] (2) After the esterification reaction is completed, the intermediate product is subjected to polycondensation reaction to obtain the waterborne polyester.

[0088] In some implementations, step (1) includes a first heating and a second heating.

[0089] In some implementations, in step (1), the first temperature rise is controlled to 100-140°C.

[0090] In some embodiments, in step (1), the first temperature rise is controlled to 110-130°C, preferably 115°C, 120°C, 125°C, 130°C, etc.

[0091] In some implementations, in step (1), the second temperature rise is controlled to 220-240°C.

[0092] In some embodiments, in step (1), the second temperature rise is controlled to 225-235°C, preferably 226°C, 227°C, 228°C, 229°C, 230°C, 231°C, 232°C, 233°C, 234°C, 235°C, etc.

[0093] In some implementations, in step (1), the rate of the second heating is controlled to be 0.4 to 0.6 °C / min.

[0094] In some embodiments, in step (1), the rate of the second heating is controlled to be 0.45 to 0.55 °C / min, specifically preferably 0.46 °C / min, 0.47 °C / min, 0.48 °C / min, 0.49 °C / min, 0.50 °C / min, 0.51 °C / min, 0.52 °C / min, 0.53 °C / min, 0.54 °C / min, etc.

[0095] In some embodiments, in step (1), after the first heating is completed, the reaction system is stirred.

[0096] In some embodiments, the stirring rate is controlled to be 60 to 100 rpm.

[0097] In some embodiments, the stirring rate is controlled to be 60-80 rpm, and more preferably 62 rpm, 64 rpm, 66 rpm, 68 rpm, 70 rpm, 72 rpm, 74 rpm, 76 rpm, 78 rpm, etc.

[0098] In some embodiments, in step (1), the catalyst is selected from one or more of Na, Zn, Mn, Mg, Ca, Co acetate and titanate.

[0099] In some embodiments, in step (1), the catalyst is selected from one or more of Na, Zn acetate and tetrabutyl titanate.

[0100] In some embodiments, in step (1), the pressure of the esterification reaction is controlled to be atmospheric pressure.

[0101] In some embodiments, the esterification reaction in step (1) is carried out under a nitrogen atmosphere.

[0102] In some embodiments, the esterification reaction ends when the amount of byproducts collected is greater than 90% of the theoretical value.

[0103] In some embodiments, in step (2), the temperature of the polycondensation reaction is controlled to be 220–300°C.

[0104] In some embodiments, in step (2), the temperature of the polycondensation reaction is controlled to be 220-260°C, preferably 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, or 260°C.

[0105] In some embodiments, in step (2), the polycondensation reaction is controlled to be carried out at a stirring rate of 40 to 100 rpm.

[0106] In some embodiments, in step (2), the polycondensation reaction is controlled to be carried out at a stirring rate of 40 to 80 rpm, preferably 40 rpm, 45 rpm, 50 rpm, 55 rpm, 60 rpm, 65 rpm, 70 rpm, 75 rpm, 80 rpm, etc.

[0107] In some embodiments, in step (2), the polycondensation reaction is controlled to be carried out under negative pressure conditions.

[0108] In some embodiments, in step (2), the pressure of the polycondensation reaction is controlled to be below 100 Pa.

[0109] In some implementations, in step (2), the pressure of the polycondensation reaction system is gradually reduced from atmospheric pressure to below 100 Pa within 30 minutes.

[0110] In some embodiments, in step (2), the polycondensation reaction occurs in the presence of a stabilizer selected from one or more of phosphoric acid, phosphate esters, phosphorous acid, and phosphite esters.

[0111] In some embodiments, the stabilizer is selected from phosphate esters.

[0112] In some embodiments, the stabilizer is selected from trimethyl phosphate.

[0113] The method for preparing waterborne polyester provided by this invention has a simple synthesis route, is easy to operate, uses readily available raw materials, has low cost, and is easy to industrialize; moreover, the waterborne polyester provided by this invention has moderate intrinsic viscosity, moderate glass transition temperature, and good solubility.

[0114] A third aspect of the present invention provides a composition comprising the aqueous polyester described in any one of the preceding claims.

[0115] The fourth aspect of the present invention provides the application of the waterborne polyester described in any of the above claims in waterborne coatings.

[0116] The present invention will be further described below with reference to specific embodiments and comparative examples.

[0117] Example 1

[0118] Under nitrogen protection, add 256.01g terephthalic acid, 170.67g isophthalic acid, 75.07g adipic acid, 30.43g sodium dimethyl isophthalate-5-sulfonate, 419.74g dibutylmalonate, 213.99g neopentyl glycol, and 277.75g sodium phthalate to a 2L stainless steel reactor. 2-Methyl-1,3-propanediol and 156.34g of 1,2-propanediol, along with 0.16g of tetrabutyl titanate, 0.16g of sodium acetate, and 0.16g of zinc acetate catalysts, were added simultaneously. The reaction temperature was raised to approximately 120℃, and stirring was started at a rate of 60 rpm. A programmed temperature increase was then implemented at a rate of 0.5℃ / min, reaching a maximum temperature of 235℃. This temperature was maintained until the byproduct yield reached over 90%, at which point esterification was terminated. The system was then cooled to below 220℃, and 0.2g of trimethyl phosphate was added. After stirring for 30 minutes, polycondensation began at a stirring rate of 60 rpm, with a maximum polycondensation temperature of 260℃ and a vacuum level less than 100 Pa. Polycondensation continued until the target power was achieved.

[0119] Example 2

[0120] Under nitrogen protection, the following ingredients were added to a 2L stainless steel reactor: 136.68g terephthalic acid, 205.02g isophthalic acid, 60.12g adipic acid, 36.56g sodium dimethyl isophthalate-5-sulfonate, 309.71g 2-butyl-2-ethylmalonic acid, 88.97g diethyl butylmalonate, 214.22g neopentyl glycol, 187.81g 1,2-propanediol, and 360.92g... 2,2,4-Trimethyl-1,3-pentanediol, 0.16 g tetrabutyl titanate, 0.16 g sodium acetate, and 0.16 g zinc acetate were added simultaneously. The reaction temperature was raised to about 120°C, and stirring was started at a speed of 60 r / min. Then, a programmed temperature increase was performed at a rate of 0.5°C / min, with the maximum temperature reaching 235°C. The temperature was maintained until the byproduct yield reached more than 90%, at which point esterification was terminated. The system was then cooled to below 220°C, and 0.2 g trimethyl phosphate was added. After stirring for 30 min, polycondensation began at a stirring speed of 60 r / min, with a maximum polycondensation temperature of 260°C and a vacuum degree of less than 100 Pa. Polycondensation was continued until the target power was achieved.

[0121] Example 3

[0122] Under nitrogen protection, 253.17g of terephthalic acid, 63.29g of isophthalic acid, 55.68g of adipic acid, 38.37g of sodium dimethyl isophthalate-5-sulfonate, 438.70g of diethyl isopentyl malonate, 412g of 2-methyl-1,3-propanediol, 115.95g of 1,2-propanediol, and 222.84g of [other ingredients] were added to a 2L stainless steel reactor. 2,2,4-Trimethyl-1,3-pentanediol, 0.16 g tetrabutyl titanate, 0.16 g sodium acetate, and 0.16 g zinc acetate were added simultaneously. The reaction temperature was raised to about 120°C, and stirring was started at a speed of 60 r / min. Then, a programmed temperature increase was performed at a rate of 0.5°C / min, with the maximum temperature reaching 235°C. The temperature was maintained until the byproduct yield reached more than 90%, at which point esterification was terminated. The system was then cooled to below 220°C, and 0.2 g trimethyl phosphate was added. After stirring for 30 min, polycondensation began at a stirring speed of 60 r / min, with a maximum polycondensation temperature of 260°C and a vacuum degree of less than 100 Pa. Polycondensation was continued until the target power was achieved.

[0123] Example 4

[0124] Under nitrogen protection, add 62.60g of terephthalic acid, 250.41g of isophthalic acid, 55.07g of adipic acid, 29.02g of sodium dimethyl isophthalate-5-sulfonate, 205.28g of dibutylmalonate, 410.55g of diisobutylmalonate, 271.67g of 2-methyl-1,3-propanediol, and 315.40g of [other ingredients] to a 2L stainless steel reactor. 1,2-Propanediol, 0.16g tetrabutyl titanate catalyst, 0.16g sodium acetate, and 0.16g zinc acetate were added simultaneously. The reaction temperature was raised to about 120℃, and stirring was started at a speed of 60 r / min. Then, a programmed temperature increase was performed at a rate of 0.5℃ / min, with the maximum temperature reaching 235℃. The temperature was maintained until the byproduct yield reached more than 90%, at which point esterification was terminated. The system was then cooled to below 220℃, and 0.2g trimethyl phosphate was added. After stirring for 30 min, polycondensation began at a stirring speed of 60 r / min, with a maximum polycondensation temperature of 260℃ and a vacuum degree of less than 100 Pa. Polycondensation was continued until the target power was achieved.

[0125] Example 5

[0126] Under nitrogen protection, add 220.23g terephthalic acid, 146.82g isophthalic acid, 64.58g adipic acid, 44.51g sodium dimethyl isophthalate-5-sulfonate, 240.72g dibutylmalonate, 203.53g diethyl isopentylmalonate, 184.09g neopentyl glycol, 159.29g 2-methyl-1,3-propanediol, and 336.23g of [unspecified ingredient] to a 2L stainless steel reactor. 1,2-Propanediol, 0.16g tetrabutyl titanate catalyst, 0.16g sodium acetate, and 0.16g zinc acetate were added simultaneously. The reaction temperature was raised to about 120℃, and stirring was started at a speed of 60 r / min. Then, a programmed temperature increase was performed at a rate of 0.5℃ / min, with the maximum temperature reaching 235℃. The temperature was maintained until the byproduct yield reached more than 90%, at which point esterification was terminated. The system was then cooled to below 220℃, and 0.2g trimethyl phosphate was added. After stirring for 30 min, polycondensation began at a stirring speed of 60 r / min, with a maximum polycondensation temperature of 260℃ and a vacuum degree of less than 100 Pa. Polycondensation was continued until the target power was achieved.

[0127] Example 6

[0128] Under nitrogen protection, add 184.30g terephthalic acid, 276.45g isophthalic acid, 81.06g adipic acid, 32.86g sodium dimethyl isophthalate-5-sulfonate, 271.06g diethyl di-n-propyl malonate, 231.08g neopentyl glycol, 269.94g 2-methyl-1,3-propanediol, and 253.24g... to a 2L stainless steel reactor. 1,2-Propanediol, 0.16g tetrabutyl titanate catalyst, 0.16g sodium acetate, and 0.16g zinc acetate were added simultaneously. The reaction temperature was raised to about 120℃, and stirring was started at a speed of 60 r / min. Then, a programmed temperature increase was performed at a rate of 0.5℃ / min, with the maximum temperature reaching 235℃. The temperature was maintained until the byproduct yield reached more than 90%, at which point esterification was terminated. The system was then cooled to below 220℃, and 0.2g trimethyl phosphate was added. After stirring for 30 min, polycondensation began at a stirring speed of 60 r / min, with a maximum polycondensation temperature of 260℃ and a vacuum degree of less than 100 Pa. Polycondensation was continued until the target power was achieved.

[0129] Comparative Example 1

[0130] Under nitrogen protection, add 246.33g terephthalic acid, 164.22g isophthalic acid, 72.23g adipic acid, 58.57g sodium dimethyl isophthalate-5-sulfonate, 403.88g dibutylmalonate, 216.20g neopentyl glycol, 280.62g 2-methyl-1,3-propanediol, and 157.95g... to a 2L stainless steel reactor. 1,2-Propanediol, 0.16g tetrabutyl titanate catalyst, 0.16g sodium acetate, and 0.16g zinc acetate were added simultaneously. The reaction temperature was raised to about 120℃, and stirring was started at a speed of 60 r / min. Then, a programmed temperature increase was performed at a rate of 0.5℃ / min, with the maximum temperature reaching 235℃. The temperature was maintained until the byproduct yield reached more than 90%, at which point esterification was terminated. The system was then cooled to below 220℃, and 0.2g trimethyl phosphate was added. After stirring for 30 min, polycondensation began at a stirring speed of 60 r / min, with a maximum polycondensation temperature of 260℃ and a vacuum degree of less than 100 Pa. Polycondensation was continued until the target power was achieved.

[0131] Comparative Example 2

[0132] Under nitrogen protection, add 256.98g of terephthalic acid, 171.32g of isophthalic acid, 75.35g of adipic acid, 24.44g of sodium dimethyl isophthalate-5-sulfonate, 421.34g of dibutylmalonate, 214.81g of neopentyl glycol, 278.81g of 2-methyl-1,3-propanediol, and 156.94g of [other ingredients] to a 2L stainless steel reactor. 1,2-Propanediol, 0.16g tetrabutyl titanate catalyst, 0.16g sodium acetate, and 0.16g zinc acetate were added simultaneously. The reaction temperature was raised to about 120℃, and stirring was started at a speed of 60 r / min. Then, a programmed temperature increase was performed at a rate of 0.5℃ / min, with the maximum temperature reaching 235℃. The temperature was maintained until the byproduct yield reached more than 90%, at which point esterification was terminated. The system was then cooled to below 220℃, and 0.2g trimethyl phosphate was added. After stirring for 30 min, polycondensation began at a stirring speed of 60 r / min, with a maximum polycondensation temperature of 260℃ and a vacuum degree of less than 100 Pa. Polycondensation was continued until the target power was achieved.

[0133] Comparative Example 3

[0134] Under nitrogen protection, 298.64 g of terephthalic acid, 199.10 g of isophthalic acid, 87.57 g of adipic acid, 30.18 g of sodium dimethyl isophthalate-5-sulfonate, 228.50 g of dibutylmalonate, 249.63 g of neopentyl glycol, 324.01 g of 2-methyl-1,3-propanediol, and 182.38 g of [unspecified ingredient] were added to a 2 L stainless steel reactor. 1,2-Propanediol, 0.16g tetrabutyl titanate catalyst, 0.16g sodium acetate, and 0.16g zinc acetate were added simultaneously. The reaction temperature was raised to about 120℃, and stirring was started at a speed of 60 r / min. Then, a programmed temperature increase was performed at a rate of 0.5℃ / min, with the maximum temperature reaching 235℃. The temperature was maintained until the byproduct yield reached more than 90%, at which point esterification was terminated. The system was then cooled to below 220℃, and 0.2g trimethyl phosphate was added. After stirring for 30 min, polycondensation began at a stirring speed of 60 r / min, with a maximum polycondensation temperature of 260℃ and a vacuum degree of less than 100 Pa. Polycondensation was continued until the target power was achieved.

[0135] Comparative Example 4

[0136] Under nitrogen protection, add 163.92g terephthalic acid, 109.28g isophthalic acid, 48.06g adipic acid, 29.23g sodium dimethyl isophthalate-5-sulfonate, 627.08g dibutylmalonate, 205.52g neopentyl glycol, 266.76g 2-methyl-1,3-propanediol, and 150.15g... to a 2L stainless steel reactor. 1,2-Propanediol, 0.16g tetrabutyl titanate catalyst, 0.16g sodium acetate, and 0.16g zinc acetate were added simultaneously. The reaction temperature was raised to about 120℃, and stirring was started at a speed of 60 r / min. Then, a programmed temperature increase was performed at a rate of 0.5℃ / min, with the maximum temperature reaching 235℃. The temperature was maintained until the byproduct yield reached more than 90%, at which point esterification was terminated. The system was then cooled to below 220℃, and 0.2g trimethyl phosphate was added. After stirring for 30 min, polycondensation began at a stirring speed of 60 r / min, with a maximum polycondensation temperature of 260℃ and a vacuum degree of less than 100 Pa. Polycondensation was continued until the target power was achieved.

[0137] Comparative Example 5

[0138] Under nitrogen protection, 307.89g of terephthalic acid, 205.26g of isophthalic acid, 270.84g of adipic acid, 36.60g of sodium dimethyl isophthalate-5-sulfonate, 257.36g of neopentyl glycol, 334.04g of 2-methyl-1,3-propanediol, and 188.02g of [unspecified ingredient] were added to a 2L stainless steel reactor. 1,2-Propanediol, 0.16g tetrabutyl titanate catalyst, 0.16g sodium acetate, and 0.16g zinc acetate were added simultaneously. The reaction temperature was raised to about 120℃, and stirring was started at a speed of 60 r / min. Then, a programmed temperature increase was performed at a rate of 0.5℃ / min, with the maximum temperature reaching 235℃. The temperature was maintained until the byproduct yield reached more than 90%, at which point esterification was terminated. The system was then cooled to below 220℃, and 0.2g trimethyl phosphate was added. After stirring for 30 min, polycondensation began at a stirring speed of 60 r / min, with a maximum polycondensation temperature of 260℃ and a vacuum degree of less than 100 Pa. Polycondensation was continued until the target power was achieved.

[0139] Comparative Example 6

[0140] Under nitrogen protection, add 261.39g terephthalic acid, 174.26g isophthalic acid, 76.65g adipic acid, 31.07g sodium dimethyl isophthalate-5-sulfonate, 428.56g dibutylmalonate, 325.54g ethylene glycol, and 302.53g sodium terephthalate to a 2L stainless steel reactor. 1,4-Cyclohexanediethanol, along with 0.16 g of tetrabutyl titanate, 0.16 g of sodium acetate, and 0.16 g of zinc acetate catalyst, were added simultaneously. The reaction temperature was raised to approximately 120°C, and stirring was started at a rate of 60 r / min. A programmed temperature increase was then implemented at a rate of 0.5°C / min, reaching a maximum temperature of 235°C. This temperature was maintained until the byproduct yield reached over 90%, at which point esterification was terminated. The system was then cooled to below 220°C, and 0.2 g of trimethyl phosphate was added. After stirring for 30 min, polycondensation began at a stirring rate of 60 r / min, with a maximum polycondensation temperature of 260°C and a vacuum level less than 100 Pa. Polycondensation continued until the target power was achieved.

[0141] The properties of the aqueous polyesters prepared in Examples 1-6 and Comparative Examples 1-6 were characterized.

[0142] Intrinsic viscosity test (IV): Measured using an Ubbelohde viscometer with o-chlorophenol as the solvent at 35°C. The formula for calculating intrinsic viscosity is:

[0143]

[0144] In the formula: η: intrinsic viscosity, mL / g; η sp : Specific viscosity; η r : Viscosity ratio; c: Polymer concentration, mol / L; t: Sample eluent time, s; t0: Blank sample eluent time, s.

[0145] Glass transition temperature (Tg) testing: A TA Q20 differential scanning calorimeter (USA) was used. During the test, a flow rate of 20 mL / min was applied under a nitrogen atmosphere. A 5 mg sample was placed in an alumina sample dish. The test procedure was as follows: The sample was heated from -30 °C to 180 °C at a heating rate of 10 °C / min, held at this temperature for 2 min to eliminate thermal history, and then cooled back to -30 °C at a cooling rate of 10 °C / min. Subsequently, the sample underwent a second heating process, from -30 °C to 150 °C at a heating rate of 10 °C / min. The glass transition temperature (Tg) of the sample was obtained from this second heating process.

[0146] Solubility test: Using ethylene glycol butyl ether (BCS) as an additive, the amount added is 4% of the weight of the water-based polyester. It dissolves into an aqueous solution with a solid content of 35% at 80°C.

[0147] Table 1

[0148] IV (dL / g) Tg (°C) Dissolved state Example 1 0.41 50 normal Example 2 0.43 52 normal Example 3 0.47 57 normal Example 4 0.42 64 normal Example 5 0.44 68 normal Example 6 0.42 57 normal Comparative Example 1 0.43 54 Layering after cooling Comparative Example 2 0.40 48 normal Comparative Example 3 0.42 63 normal Comparative Example 4 0.44 39 Layering after cooling Comparative Example 5 0.42 56 Dissolving gel Comparative Example 6 0.43 48 Layering after cooling

[0149] The hydrolysis resistance and storage stability of the waterborne polyesters prepared in Examples 1-6 and Comparative Examples 1-6 were tested.

[0150] Hydrolysis resistance test: The aqueous dispersions of waterborne polyester prepared in Examples 1-6 and Comparative Examples 1-6 were placed at room temperature (25°C) for 45 days, 90 days, and 180 days. The separation of the aqueous dispersions was observed. For samples that did not separate or were slightly flocculated, the acid value was determined according to the national standard GB / T 6743-2008 "Determination of acid value and total acid value of the base component of polyester resins for plastics, paints and varnishes". The results are shown in Table 2.

[0151] Table 2

[0152]

[0153] As shown in Table 2, the waterborne polyesters prepared in Examples 1-6 did not exhibit stratification even after 180 days at room temperature (25°C), demonstrating their excellent water resistance. Furthermore, the acid values ​​of the waterborne polyester dispersions in Examples 1-6 remained relatively stable or unchanged after 45 days at room temperature, and even after 180 days, the acid value change was still minimal. In contrast, the waterborne polyester dispersions in Comparative Examples 1-6 all showed stratification after 45-180 days at room temperature, indicating poor hydrolysis resistance and storage stability.

[0154] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations included in the claims. Various modifications and changes can be made to the above embodiments without departing from the scope of this disclosure. Similarly, the various technical features of the above embodiments can be arbitrarily combined to form other embodiments of the present invention that may not be explicitly described. Therefore, the above embodiments only illustrate several implementations of the present invention and do not limit the scope of protection of this patent.

Claims

1. A waterborne polyester, characterized in that, The raw materials for preparing the aqueous polyester include a dibasic acid, a dibasic alcohol, an organic sulfonate, and a compound as shown in formula (I), ； wherein R1is selected from H or C 1~6 alkyl; R2is selected from C 3~6 alkyl; R3, R4are each independently selected from H or C 1~6 alkyl; The number of carbon atoms in the dibasic alcohol main chain is an odd number selected from natural odd numbers from 3 to 25. The dibasic acid is selected from aromatic dibasic acids and aliphatic dibasic acids; the aromatic dibasic acid is selected from isophthalic acid and / or terephthalic acid; the aliphatic dibasic acid is selected from adipic acid and / or succinic acid. The organic sulfonate is selected from one or more of dimethyl isophthalate-5-sodium sulfonate, isophthalic acid-5-sodium sulfonate, bis-hydroxyethyl isophthalate-5-sodium sulfonate, and terephthalic acid-5-sodium sulfonate. The molar amount of the organic sulfonate accounts for 2-3.5% of the total molar amount of the dibasic acid, the organic sulfonate, and the compound as shown in formula (I). The molar amount of the compound as shown in formula (I) accounts for 20-50% of the total molar amount of the dibasic acid, the organic sulfonate, and the compound as shown in formula (I).

2. The aqueous polyester according to claim 1, characterized in that, R1is selected from H or C 1~4 alkyl.

3. The aqueous polyester according to claim 2, characterized in that, R1 is selected from one of H, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and t-butyl.

4. The aqueous polyester according to claim 1, characterized in that, R2is selected from C 3~5 alkyl.

5. The aqueous polyester according to claim 4, characterized in that, R2 is selected from one of n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, sec-pentyl, t-pentyl, and neopentyl.

6. The aqueous polyester according to claim 1, characterized in that, R3, R4are each independently selected from H or C 1~4 alkyl.

7. The aqueous polyester according to claim 6, characterized in that, R3, R4are each independently selected from H or C 1~3 alkyl.

8. The aqueous polyester according to claim 7, characterized in that R3 and R4 are each independently selected from one of H, methyl, and ethyl.

9. The aqueous polyester according to claim 1, characterized in that, The compound as shown in formula (I) is selected from one or more of dibutyl propylene glycol diethyl ester, 2-butyl-2-ethyl propylene glycol, isopentyl propylene glycol diethyl ester, butyl propylene glycol dimethyl ester, di-n-propyl propylene glycol diethyl ester, and diisobutyl propylene glycol diethyl ester.

10. The aqueous polyester according to claim 1, characterized in that, The molar amount of the compound as shown in formula (I) accounts for 25-50% of the total molar amount of the dibasic acid, the organic sulfonate, and the compound as shown in formula (I).

11. The aqueous polyester according to claim 10, characterized in that, The molar amount of the compound as shown in formula (I) accounts for 30-50% of the total molar amount of the dibasic acid, the organic sulfonate, and the compound as shown in formula (I).

12. The aqueous polyester according to claim 11, characterized in that, The molar amount of the compound as shown in formula (I) accounts for 32-50% of the total molar amount of the dibasic acid, the organic sulfonate, and the compound as shown in formula (I).

13. The aqueous polyester of claim 1, wherein, The organic sulfonate is dimethyl isophthalate-5-sodium sulfonate.

14. The aqueous polyester of claim 1, wherein, The number of carbon atoms in the dibasic alcohol main chain is 3, 5, 7, or 9.

15. The aqueous polyester according to claim 14, characterized in that, The dibasic alcohol is selected from one or more of neopentyl glycol, 2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 1,2-propanediol, and 2,2,4-trimethyl-1,3-pentanediol.

16. The aqueous polyester of claim 1, wherein, The ratio of the total moles of the dibasic alcohol, the dibasic acid, the organic sulfonate, and the compound as shown in formula (I) is (1.5-2.0):

1.

17. The aqueous polyester according to claim 16, characterized in that, The ratio of the total moles of the dibasic alcohol, the dibasic acid, the organic sulfonate, and the compound as shown in formula (I) is (1.5-1.9):

1.

18. A method of producing the aqueous polyester according to any one of claims 1 to 17, characterized by, The preparation method comprises: (1) putting the dibasic acid, the dibasic alcohol, the organic sulfonate, the compound as shown in formula (I), and a catalyst into a reactor, warming the reaction system to perform esterification, and obtaining an intermediate product; (2) After the esterification reaction is completed, the intermediate product is subjected to a polycondensation reaction to obtain the aqueous polyester.

19. The method of claim 18, wherein, In step (1), the temperature rising comprises a first temperature rising and a second temperature rising.

20. The method of claim 19, wherein, In step (1), the first temperature rising is controlled to be 100-140℃.

21. The method of claim 20, wherein, In step (1), the first temperature rising is controlled to be 110-130℃.

22. The preparation method according to claim 19, characterized in that, In step (1), the second temperature rising is controlled to be 220-240℃.

23. The preparation method according to claim 19, characterized in that, In step (1), the second temperature rising is controlled to be 225-235℃.

24. The method of claim 19, wherein, The rate of the second temperature rising is controlled to be 0.4-0.6℃ / min.

25. The method of claim 24, wherein, The rate of the second temperature rising is controlled to be 0.45-0.55℃ / min.

26. The preparation method according to claim 19, characterized in that, In step (1), after the first temperature rising is completed, the reaction system is stirred.

27. The method of claim 26, wherein, The rate of the stirring is controlled to be 60-100rpm.

28. The preparation method according to claim 26, characterized in that, The rate of the stirring is controlled to be 60-80rpm.

29. The method of claim 18, wherein the method is carried out at a temperature of about 20°C to about 30°C. In step (1), the catalyst is selected from one or more of Na, Zn, Mn, Mg, Ca, Co acetate and titanium acid ester.

30. The preparation method according to claim 29, characterized in that, In step (1), the catalyst is selected from one or more of Na, Zn acetate and tetrabutyl titanate.

31. The method of claim 18, wherein the method further comprises, In step (1), the pressure of the esterification reaction is controlled to be normal pressure.

32. The method of claim 18, wherein the method is carried out at a temperature of about 20°C to about 30°C. In step (1), the esterification reaction is carried out under nitrogen atmosphere.

33. The method of claim 18, wherein the method is carried out at a temperature of about 20°C to about 30°C. In step (2), the temperature of the polycondensation reaction is controlled to be 220-300℃.

34. The preparation method according to claim 33, characterized in that, In step (2), the temperature of the polycondensation reaction is controlled to be 220-260℃.

35. The method of claim 18, wherein the method is carried out at a temperature of about 20°C to about 30°C. In step (2), the polycondensation reaction is carried out at a stirring rate of 40-100rpm.

36. The method of claim 35, wherein, In step (2), the polycondensation reaction is carried out at a stirring rate of 40-80rpm.

37. The method of claim 18, wherein the method is carried out at a temperature of about 20°C to about 30°C. In step (2), the pressure of the polycondensation reaction is controlled to be below 100Pa.

38. The method of claim 18, wherein the method is carried out at a temperature of about 20 °C to about 30 °C. In step (2), the polycondensation reaction is carried out in the presence of a stabilizer.

39. The method of claim 38, wherein, The stabilizer is selected from one or more of phosphoric acid, phosphoric acid ester, phosphorous acid and phosphorous acid ester.

40. The method of claim 39, wherein The stabilizer is trimethyl phosphate.

41. A composition comprising, The composition comprises the aqueous polyester according to any one of claims 1-17.

42. Use of the aqueous polyester according to any one of claims 1-17 in an aqueous paint film.

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