A long-lasting modified polyester dispersion and a method for preparing the same

Abstract

The application belongs to the technical field of water-based polyester materials, and discloses a long-acting modified polyester dispersion and a preparation method thereof. The dispersion is composed of water, modified polyester and volatile tertiary amine, and the solid content is 50-55 wt%. Taking the total mass of the modified polyester as 100 wt%, the organic polysiloxane segment accounts for 3.5-6.0 wt%, the phosphorus-containing structural unit accounts for 2.0-5.0 wt%, the carboxyl branched connecting group accounts for 1.5-4.0 wt%, and the rest is the polyester segment; the feeding amount of the volatile tertiary amine is 0.6-3.2 wt%. During the preparation, the following steps are sequentially performed: basic polyester preparation, carboxylation, graft modification and phosphorus-containing structure introduction, tertiary amine neutralization, and phase inversion water dispersion. The obtained dispersion has small particle size and few agglomerates, and can be stored for a long time even at high solid content.

Description

Technical Field

[0001] This invention relates to the field of waterborne polymer materials technology, specifically to a long-lasting modified polyester dispersion and its preparation method. Background Technology

[0002] Polyester resins exhibit good film-forming properties, adhesion, flexibility, and mechanical properties, making them widely used in coatings, adhesives, and industrial protective materials. To reduce the use of organic solvents and lower volatile organic compound (VOC) emissions, water-dispersible polyesters have gained increasing attention in recent years. Current methods often involve introducing hydrophilic groups such as carboxyl groups into the polyester, followed by neutralization with tertiary amines to enable dispersion in water. The problem lies in the difficulty of controlling the hydrophilic / hydrophobic balance, ionization degree, and phase inversion process when simultaneously increasing solids content and introducing organopolysiloxanes and phosphorus-containing structures. This often results in dispersions with increased particle size, abnormal viscosity, and even stratification, sedimentation, flocculation, or gelation. A more subtle issue arises: initially uniform in appearance, but after prolonged storage or at higher temperatures, particle size gradually increases, viscosity rises, and sedimentation and stratification begin, affecting storage stability and batch consistency. Therefore, a long-lasting modified polyester dispersion and its preparation method are indeed needed—one that maintains small particle size, low agglomerate content, and long-term storage tolerance even under high solids content and multiple modification conditions. Summary of the Invention

[0003] To address the problems of particle size increase, viscosity increase, stratification, sedimentation, flocculation, or gelation that easily occur in existing waterborne long-acting modified polyester dispersions under conditions of high solid content and multifunctional modification, this invention proposes a long-acting modified polyester dispersion and its preparation method.

[0004] A long-lasting modified polyester dispersion comprising water, modified polyester, and a volatile tertiary amine; Based on a total mass of 100 wt% of the long-acting modified polyester dispersion, the solid content of the long-acting modified polyester dispersion is 50–55 wt%. Based on a theoretical dry basis total mass of 100 wt% for the modified polyester, the amount of volatile tertiary amine fed is 0.6–3.2 wt%. Based on a theoretical dry basis total mass of 100 wt% for the modified polyester, and calculated according to the mass of the effective components of the raw materials used to form the corresponding structure, the modified polyester comprises 3.5–6.0 wt% organopolysiloxane segments, 2.0–5.0 wt% phosphorus-containing structural units, 1.5–4.0 wt% carboxyl-branched linking groups, and the balance being polyester segments; The organopolysiloxane segment is grafted onto the polyester segment via the carboxyl-containing branched linker group, and the phosphorus-containing structural unit is introduced into the modified polyester through a reaction.

[0005] Furthermore, the solid content was determined using the drying loss method at 105±2℃.

[0006] Furthermore, the polyester segment is formed by esterification and polycondensation reactions of a basic polyol component and a basic polyacid component; based on a total feed mass of 100 wt% for the basic polyol component, the basic polyol component consists of 52-58 wt% neopentyl glycol and 42-48 wt% 1,4-cyclohexanediethanol; based on a total feed mass of 100 wt% for the basic polyacid component, the basic polyacid component consists of 68-72 wt% isophthalic acid and 28-32 wt% hexahydrophthalic anhydride.

[0007] Furthermore, the carboxyl-containing branched linker group is formed by the reaction of trimellitic anhydride with the hydroxyl groups in the polyester segment.

[0008] Furthermore, the organopolysiloxane segment is formed from a single-terminal epoxy polydimethylsiloxane; at least some of the carboxyl groups in the carboxyl-branched linking group react with the epoxy groups in the single-terminal epoxy polydimethylsiloxane to form a β-hydroxy ester linking structure, and the modified polyester retains unreacted carboxyl groups.

[0009] Furthermore, the phosphorus-containing structural unit is introduced by a reaction of a hydroxyalkylphosphonate compound and a hydroxyalkylphosphate monoester compound; based on a total effective component feed mass of 100 wt% for the hydroxyalkylphosphonate compound and the hydroxyalkylphosphate monoester compound, the effective component feed amount of the hydroxyalkylphosphonate compound is 48-52 wt%, and the effective component feed amount of the hydroxyalkylphosphate monoester compound is 48-52 wt%.

[0010] Furthermore, the volatile tertiary amine is composed of dimethylethanolamine and triethylamine; based on a total mass of 100 wt% of the volatile tertiary amine, the amount of dimethylethanolamine is 52-58 wt%, and the amount of triethylamine is 42-48 wt%.

[0011] Furthermore, the average particle size of the long-acting modified polyester dispersion, measured by dynamic light scattering at 25±1℃, is no greater than 150 nm, and the PDI is no greater than 0.30; the content of agglomerates, measured by filtration weighing using a 100 μm filtration medium, is no greater than 0.15 wt%; the long-acting modified polyester dispersion is loaded into a sealed glass container, with the loading amount being 80±5% of the effective volume of the sealed glass container, and stored at 50±2℃ for 30 days and then placed at 25±2℃ for 24 hours, without any visible layering, precipitation, oil separation, flocculation, or gelation.

[0012] The present invention also provides a method for preparing the above-mentioned long-lasting modified polyester dispersion, comprising the following steps: S1. The basic polyol component and the basic polyacid component are subjected to esterification and polycondensation reaction to obtain a hydroxyl-containing basic polyester. S2. React trimellitic anhydride with the hydroxyl groups in the base polyester to obtain a carboxylated polyester containing carboxyl branched linkage groups. S3. First, react the carboxylated polyester with a single-terminated epoxy polydimethylsiloxane, then add a hydroxyalkylphosphonate compound and a hydroxyalkylphosphate monoester compound to react and obtain a modified polyester containing organopolysiloxane segments and phosphorus-containing structural units. S4. Add volatile tertiary amine to the modified polyester for neutralization, and gradually add water under high-speed mechanical stirring to cause the system to reverse and form a uniform long-lasting modified polyester dispersion; control the amount of water added so that the solid content of the obtained long-lasting modified polyester dispersion is 50-55 wt%.

[0013] Furthermore, in step S1, the temperature of the esterification reaction is 160–195°C, and the temperature of the polycondensation reaction is 195–225°C.

[0014] Further, in step S2, the base polyester is cooled to 130-170°C and then trimellitic anhydride is added to carry out the reaction.

[0015] Further, in step S3, the carboxylated polyester is first reacted with a single-terminated epoxy polydimethylsiloxane at 100–140°C, and then a hydroxyalkylphosphonate compound and a hydroxyalkylphosphate monoester compound are added at 120–140°C to carry out the reaction.

[0016] Further, in step S4, the modified polyester is cooled to 55-85°C and then neutralized with volatile tertiary amine, and water is gradually added under high-speed mechanical stirring at 600-1200 r / min for dispersion.

[0017] Further, in step S4, the initial water addition rate is 5-10 g / min, which is 0.5-1.0 wt% / min based on the theoretical dry basis total mass of the modified polyester as 100 wt%. After the reaction system undergoes phase inversion and forms a uniform aqueous dispersion, the water addition rate is increased to 20-30 g / min, i.e., 2.0-3.0 wt% / min. After the system completes phase inversion and forms a uniform aqueous dispersion, high-speed mechanical stirring continues for 20-40 min.

[0018] Beneficial effects

[0019] 1. This invention achieves long-lasting modified polyester dispersions by synergistically controlling the structural composition of the modified polyester, the neutralization of the composite volatile tertiary amine, and the phase inversion water dispersion conditions. This allows the resulting dispersions to maintain a small average particle size, a narrow particle size distribution, and a low agglomerate content even at a relatively high solid content of 50–55 wt%. It also reduces the risk of particle size increase, abnormal viscosity, stratification, sedimentation, flocculation, or gelation during storage.

[0020] 2. This invention utilizes carboxyl-containing branched linking groups to graft organopolysiloxane segments onto polyester segments, while retaining carboxyl groups in the modified polyester that can be neutralized by volatile tertiary amines. These linking groups possess both grafting sites for organopolysiloxanes and ionization sites required for water dispersion, allowing the reactive linking of organopolysiloxane segments and the water dispersion of the modified polyester to complement each other, thus reducing the migration, aggregation, precipitation, and phase separation of organopolysiloxanes during storage.

[0021] 3. This invention introduces both hydroxyalkylphosphonate compounds and hydroxyalkylphosphate monoester compounds into modified polyesters. The introduction of both types of phosphorus-containing compounds via reaction helps reduce the impact of free phosphorus components on the stability of the dispersion system. The synergistic effect of the two compounds results in a dispersion that is superior to systems using only one type of phosphorus-containing compound in terms of average particle size, particle size distribution, aggregate content, and storage stability.

[0022] 4. This invention uses dimethylethanolamine and triethylamine to form a composite volatile tertiary amine system. The two tertiary amines cooperate with each other during neutralization and water dispersion, which is beneficial for the modified polyester to uniformly complete phase inversion and water dispersion, and achieves a balance between particle size, viscosity and storage stability in the resulting dispersion.

[0023] 5. In this invention, the neutralization temperature of the tertiary amine is controlled at 55–85°C, and water is added in stages for water dispersion under high-speed stirring at 600–1200 r / min. With proper coordination of temperature, stirring, and water addition rate, the phase inversion process is easy to control, local water concentration does not change abruptly, resin is not prone to agglomeration, and the resulting high-solids-content system has small particle size and uniform distribution.

[0024] 6. The reactive grafting of organopolysiloxanes, the joint introduction of two types of phosphorus-containing structures, the neutralization of complex tertiary amines, and the controlled phase inversion water dispersion are not isolated from each other, but jointly affect the hydrophilicity-hydrophobicity balance, ionization state, and phase inversion process of the modified polyester, thereby improving the uniformity of the dispersion and its long-term storage stability.

[0025] 7. The dispersions obtained in the examples had a solid content of 50.8–54.7 wt%, an average particle size of 113–141 nm, a PDI of 0.25–0.29, and a coagulant content of 0.06–0.12 wt%. They remained stable after centrifugation at 3000 r / min for 30 min, and no obvious stratification, sedimentation, flocculation, or gelation was observed after sealed storage at 50°C for 30 days. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the preparation process of the long-acting modified polyester dispersion of the present invention. Detailed Implementation

[0027] Unless otherwise specified, the conditions in the examples were performed under standard conditions or as recommended by the manufacturer. Reagents and instruments not labeled with their manufacturers were all commercially available standard products. Unless otherwise stated, the reaction equipment, stirring devices, feeding methods, and test conditions used in the following examples and comparative examples are identical. Figure 1 The preparation process of the dispersion of the present invention is given below, in conjunction with... Figure 1 The following examples further illustrate the solution.

[0028] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are as follows: Neopentyl glycol, abbreviated as NPG, CAS number 126-30-7, has a purity of 99.0%. 1,4-Cyclohexanediethanol, abbreviated as CHDM, CAS number 105-08-8, molecular weight 144.21, purity not less than 99.5%; IPA (isophthalic acid), CAS number 121-91-5, molecular weight 166.13, purity 99.9%; Hexahydrophthalic anhydride, abbreviated as HHPA, CAS number 85-42-7, molecular weight 154.16, purity not less than 99.0%; Trimeric triglyceride, abbreviated as TMA, CAS number 552-30-7, molecular weight 192.13, purity not less than 98.0%; The single-ended epoxy polydimethylsiloxane, abbreviated as EP-PDMS, uses a single-ended epoxy modified organosilicon fluid with model number X-22-173BX. The kinematic viscosity at 25°C is about 30 mm² / s, and the reactive group equivalent is about 2500 g / mol. The hydroxyalkyl phosphonate compound, abbreviated as P1, is N,N-bis(2-hydroxyethyl)aminomethylenephosphonate diethyl ester, trade name FRC-6, CAS number 2781-11-5, molecular weight 255.25, purity 98.0%; The hydroxyalkyl phosphate monoester compound, abbreviated as P2, is a mono(2-hydroxyethyl) phosphate, also known as 2-hydroxyethyl phosphate, with CAS number 1892-26-8, molecular weight 142.05, and purity 98.0%. Dimethylethanolamine, abbreviated as DMEA, CAS number 108-01-0, has a purity of not less than 99.0%. Triethylamine, abbreviated as TEA, CAS number 121-44-8, has a purity of not less than 99.7%. The esterification catalyst used is tetrabutyl titanate, CAS number 5593-70-4, with a purity of not less than 99.0%. The carboxyl-epoxy ring-opening catalyst uses triphenylphosphine, CAS number 603-35-0, with a purity of not less than 99.0%. The single-ended dihydroxyl polydimethylsiloxane used was product HY-2000, with an average molecular weight of 2000-2100, a hydroxyl equivalent of 1000-1050 g / eq, and a viscosity of 80-90 mPa·s at 25℃. It was used only for Comparative Example 8. The water used is deionized water.

[0029] The effective ingredient amounts of P1 and P2 are calculated as the product of the actual mass of the corresponding raw material and its purity.

[0030] The high-speed mechanical stirring described in this application refers to the use of a high-speed dispersing paddle to stir the reaction system, causing the modified polyester to undergo an inversion during the water addition process and disperse uniformly in the water. Unless otherwise specified, the rotational speed of the high-speed dispersing paddle is 800 r / min.

[0031] Unless otherwise specified, the following examples and comparative examples are based on a theoretical dry basis total mass of 1000.0 g of modified polyester. The content of each structural unit in the modified polyester is calculated according to the mass of the effective components of the raw materials used to form the corresponding structure. Esterification catalyst and carboxyl-epoxy ring-opening catalyst are not included in the content of each structural unit.

[0032] The amount of volatile tertiary amine fed is calculated as a percentage of the total mass of DMEA and TEA fed to the total theoretical dry weight of the modified polyester.

[0033] Example 1

[0034] A long-lasting modified polyester dispersion. Based on a theoretical dry basis total mass of 100 wt% of the modified polyester, the modified polyester contains 89.2 wt% polyester segments, 2.5 wt% carboxyl-branched linking groups, 4.8 wt% organopolysiloxane segments, and 3.5 wt% phosphorus-containing structural units.

[0035] The basic polyol is composed of 55 wt% NPG and 45 wt% CHDM, and the basic polyacid is composed of 70 wt% IPA and 30 wt% HHPA; the mass ratio of the effective components of P1 to P2 is 50:50; the volatile tertiary amine is prepared by DMEA and TEA in a ratio of 55:45, with an input amount of 1.875 wt% (based on a theoretical dry basis of 100 wt%).

[0036] The preparation steps are as follows.

[0037] Preparation of S1 base polyester

[0038] In a reactor equipped with a stirrer, thermometer, nitrogen inlet pipe, water separator, and pressure reducing device, add 238.5 g NPG, 195.2 g CHDM, 394.4 g IPA, 169.0 g HHPA, and 0.50 g tetrabutyl titanate. Purge with nitrogen, set the stirring speed to 100 r / min, and heat to 120℃, maintaining this temperature while stirring for 30 min.

[0039] The temperature was then raised to 160℃ and held for 60 minutes, followed by a gradual increase to 190℃ for esterification. The water generated during the reaction was discharged through a water separator. Once the acid value dropped to no more than 15 mgKOH / g, the temperature was raised to 210℃, and the pressure inside the reactor was gradually reduced to -0.085 to -0.095 MPa for polycondensation. When the acid value dropped to 3–8 mgKOH / g, the hydroxyl value to 18–28 mgKOH / g, and the change in acid value between two consecutive samples did not exceed 1 mgKOH / g, the vacuum was released and nitrogen gas was introduced to obtain the hydroxyl-containing basic polyester.

[0040] Preparation of S2 carboxylated polyester

[0041] The S1 base polyester was cooled to 150°C, and the stirring speed was adjusted to 120 r / min. 25.0 g of TMA was added in batches over 20 min, with the temperature controlled between 145 and 155°C during the addition. After the addition was complete, the mixture was reacted at 150°C for another 90 min to obtain a carboxylated polyester with carboxyl-branched linker groups.

[0042] Preparation of S3 modified polyester

[0043] The S2 carboxylated polyester was cooled to 115°C and stirred at 150 r / min. 48.0 g of EP-PDMS and 0.10 g of triphenylphosphine were mixed and added to the reactor within 30 min, with the temperature controlled at 110-120°C during addition. After addition, the reaction was carried out at 115°C for 120 min.

[0044] The temperature was then raised to 130°C, and 17.86 g of P1 and 17.86 g of P2 were mixed and added over 30 minutes. After addition, the reaction was carried out at 130°C for 60 minutes. Then, the pressure inside the reactor was gradually reduced to -0.075 to -0.085 MPa, and the reaction was continued at 130°C for 120 minutes. During this period, samples were taken every 30 minutes to measure the acid value and hydroxyl value. When the change in acid value between two consecutive tests did not exceed 1 mgKOH / g and the change in hydroxyl value did not exceed 2 mgKOH / g, the vacuum was released and nitrogen gas was introduced to obtain the modified polyester.

[0045] S4 neutralization and water dispersion

[0046] Reduce the temperature of the S3 modified polyester to 70°C and adjust the stirring speed to 200 r / min. Mix 10.31 g DMEA and 8.44 g TEA thoroughly and add them gradually over 15 min, keeping the temperature between 65 and 75°C during the addition. Stir for another 30 min after the addition is complete.

[0047] Switch to a high-speed dispersing paddle, adjust the speed to 800 r / min, and gradually add deionized water over 60 min. Initially, control the water addition rate at 5–10 g / min; once the system undergoes phase inversion and forms a uniform aqueous dispersion, increase the rate to 20–30 g / min. Stop adding water once phase inversion is complete and dispersion is uniform, then disperse again at 800 r / min for 30 min. Cool to no higher than 40℃ to obtain the long-lasting modified polyester dispersion.

[0048] Example 2

[0049] It is largely the same as Example 1, except that: The modified polyester comprises 93.0 wt% polyester segments, 1.5 wt% carboxyl-branched linking groups, 3.5 wt% organopolysiloxane segments, and 2.0 wt% phosphorus-containing structural units (based on a theoretical dry basis of 100 wt%). The basic polyol consists of 52 wt% NPG and 48 wt% CHDM, and the basic polyacid consists of 68 wt% IPA and 32 wt% HHPA. The effective component mass ratio of P1 to P2 is 48:52. The volatile tertiary amine is prepared from DMEA and TEA in a 52:48 ratio, with a feed amount of 0.667 wt%.

[0050] S1: Add 236.2 g NPG, 218.1 g CHDM, 396.8 g IPA, 186.7 g HHPA, and 0.50 g tetrabutyl titanate. The maximum esterification temperature is 180°C, and the polycondensation temperature is 195°C. S2: Lower the temperature of the base polyester to 130°C, add 15.0 g TMA, and react at 130°C for 90 min. S3: Lower the temperature of the carboxylated polyester to 100°C, add 35.0 g EP-PDMS and 0.08 g triphenylphosphine, and react at 100°C for 120 min; then raise the temperature to 120°C, add 9.80 g P1 and 10.61 g P2, and react at 120°C for 180 min. S4: Lower the temperature of the modified polyester to 55°C, add 3.47 g DMEA and 3.20 g TEA for neutralization, then add deionized water at 800 rpm according to the staged water addition method in Example 1 until phase inversion is complete and the dispersion is uniform. Disperse for another 30 minutes, then cool to no higher than 40°C to obtain the final product.

[0051] Example 3

[0052] It is largely the same as Example 1, except that: The modified polyester comprises 85.0 wt% polyester segments, 4.0 wt% carboxyl-branched linking groups, 6.0 wt% organopolysiloxane segments, and 5.0 wt% phosphorus-containing structural units (based on a theoretical dry basis of 100 wt%). The basic polyol consists of 58 wt% NPG and 42 wt% CHDM, and the basic polyacid consists of 72 wt% IPA and 28 wt% HHPA. The effective component mass ratio of P1 to P2 is 52:48. The volatile tertiary amine is prepared from DMEA and TEA in a 58:42 ratio, with a feed amount of 3.077 wt%.

[0053] S1: Add 238.6 g NPG, 172.8 g CHDM, 389.0 g IPA, 151.3 g HHPA, and 0.50 g tetrabutyl titanate. The maximum esterification temperature is 195°C, and the polycondensation temperature is 225°C. S2: Lower the temperature of the base polyester to 170°C, add 40.0 g TMA, and react at 170°C for 60 min. S3: Lower the temperature of the carboxylated polyester to 140°C, add 60.0 g EP-PDMS and 0.12 g triphenylphosphine, and react at 140°C for 90 min; then add 26.53 g P1 and 24.49 g P2, and react at 140°C for 180 min. S4: Lower the temperature of the modified polyester to 85°C, add 17.85 g DMEA and 12.92 g TEA for neutralization, and then add deionized water at 800 r / min according to the staged water addition method in Example 1 until phase inversion is complete and the dispersion is uniform. Disperse for another 30 minutes, then cool to no higher than 40°C to obtain the final product.

[0054] Example 4

[0055] The process is largely the same as in Example 1, except for S4. The modified polyester's structural composition, base polyol, base polyacid, the ratio of effective components P1 and P2, and the composition and amount of volatile tertiary amine are all the same as in Example 1.

[0056] Cool the S3 modified polyester to 55°C and adjust the stirring speed to 200 r / min. Mix 10.31 g DMEA and 8.44 g TEA thoroughly and gradually add them over 15 min, maintaining the temperature at 55–60°C during addition. After the addition is complete, stir for another 30 min. Switch to a high-speed dispersing paddle and adjust the speed to 600 r / min, gradually adding deionized water over 60 min. Initially, add water at a rate of 5–10 g / min; increase this rate to 20–30 g / min after the reverse rotation and the formation of a uniform aqueous dispersion. Stop adding water once the reverse rotation is complete and the dispersion is uniform, and then disperse at 600 r / min for another 30 min. Cool the mixture to no higher than 40°C to obtain the final product.

[0057] Example 5

[0058] The process is largely the same as in Example 1, except for S4. The modified polyester's structural composition, base polyol, base polyacid, the ratio of effective components P1 and P2, and the composition and amount of volatile tertiary amine are all the same as in Example 1.

[0059] Cool the S3 modified polyester to 85°C and adjust the stirring speed to 200 r / min. Mix 10.31 g DMEA and 8.44 g TEA thoroughly and gradually add them over 15 min, maintaining the temperature at 80–85°C during addition. After the addition is complete, stir for another 30 min. Switch to a high-speed dispersing paddle and adjust the speed to 1200 r / min, gradually adding deionized water over 60 min. Initially, add water at a rate of 5–10 g / min; increase this rate to 20–30 g / min after the reverse rotation and the formation of a uniform aqueous dispersion. Stop adding water once the reverse rotation is complete and the dispersion is uniform, and then disperse at 1200 r / min for another 30 min. Cool the mixture to no higher than 40°C to obtain the final product.

[0060] Example 6

[0061] Similar to Example 1, the modified polyester has the same structural composition, base polyol, base polyacid, effective component feeding ratio of P1 and P2, and composition and feeding amount of volatile tertiary amine. The difference is that the reaction conditions for each step are as follows.

[0062] S1 is heated to 160℃ and held for 60 min, then gradually increased to 185℃ for esterification. The generated water is discharged through a water separator. Once the acid value drops to no more than 15 mgKOH / g, the temperature is raised to 215℃, and the pressure inside the reactor is gradually reduced to -0.085 to -0.095 MPa for polycondensation. When the acid value is 3–8 mgKOH / g, the hydroxyl value is 18–28 mgKOH / g, and the change in acid value between two consecutive samples does not exceed 1 mgKOH / g, the vacuum is released and nitrogen gas is introduced to obtain a hydroxyl-containing basic polyester.

[0063] S2 lowers the base polyester to 140°C, and adds 25.0 g of TMA in batches over 20 min, with the temperature controlled between 135 and 145°C during the addition; after the addition is complete, react at 140°C for 90 min to obtain carboxylated polyester.

[0064] S3 lowered the temperature of the carboxylated polyester to 105°C, added 48.0 g of EP-PDMS and 0.10 g of triphenylphosphine, and reacted at 105°C for 120 min. The temperature was then raised to 125°C, and 17.86 g of P1 and 17.86 g of P2 were added, reacting at 125°C for 60 min. The pressure inside the reactor was then gradually reduced to -0.075 to -0.085 MPa, and the reaction continued at 125°C for another 120 min. When the change in acid value between two consecutive samples did not exceed 1 mg KOH / g and the change in hydroxyl value did not exceed 2 mg KOH / g, the vacuum was released and nitrogen gas was introduced to obtain the modified polyester.

[0065] S4: Cool the modified polyester to 65°C and adjust the stirring speed to 200 r / min. Gradually add 10.31 g DMEA and 8.44 g TEA after mixing thoroughly, stirring for another 30 min after the addition is complete. Switch to a high-speed dispersing paddle, adjusting the speed to 1000 r / min, and gradually add deionized water over 60 min. Initially, add water at a rate of 5–10 g / min; increase to 20–30 g / min after the reverse rotation and the formation of a uniform aqueous dispersion. Stop adding water once the reverse rotation is complete and the dispersion is uniform, and then disperse at 1000 r / min for another 30 min. Cool to no higher than 40°C to obtain the final product.

[0066] Comparative Example 1

[0067] The process was largely the same as in Example 1, except that EP-PDMS and triphenylphosphine were not added in S3. After completing the reaction introduction of P1 and P2 and the neutralization and water dispersion in S4 according to Example 1, the dispersion was cooled to no higher than 40°C, and then 48.0 g of EP-PDMS was added. The dispersion was then dispersed at 800 r / min for 30 min to obtain the dispersion of Comparative Example 1.

[0068] Comparative Example 2

[0069] The process was largely the same as in Example 1, except that P2 was not added in S3, and only 35.71 g of P1 (35.0 g of active ingredient) was added. The remaining raw materials and conditions were the same as in Example 1, resulting in the dispersion of Comparative Example 2.

[0070] Comparative Example 3

[0071] The process was largely the same as in Example 1, except that P1 was not added in S3, and only 35.71 g of P2 (35.0 g of active ingredient) was added. The remaining raw materials and conditions were the same as in Example 1, resulting in the dispersion of Comparative Example 3.

[0072] Comparative Example 4

[0073] The process was largely the same as in Example 1, except that only 18.75 g of DMEA was added in S4, and no TEA was added. The amount of volatile tertiary amine added remained at 1.875 wt% (based on a theoretical dry basis of 100 wt%). The remaining raw materials and conditions were the same as in Example 1, yielding the dispersion of Comparative Example 4.

[0074] Comparative Example 5

[0075] The process was largely the same as in Example 1, except that only 18.75 g of TEA was added in S4, and DMEA was not added. The amount of volatile tertiary amine added remained at 1.875 wt% (based on a theoretical dry basis of 100 wt%). The remaining raw materials and conditions were the same as in Example 1, yielding the dispersion of Comparative Example 5.

[0076] Comparative Example 6

[0077] The process was largely the same as in Example 1, except for step S4. After the modified polyester was neutralized, a regular dispersion paddle was used, and the speed was adjusted to only 300 r / min. Deionized water was gradually added in stages, following the water addition time and method of Example 1: initially 5–10 g / min, then increased to 20–30 g / min, with the total water addition being the same as in Example 1. After the addition was complete, the mixture was stirred at 300 r / min for another 30 min to obtain the dispersion of Comparative Example 6. Except for the water dispersion speed, the other raw materials and conditions were the same as in Example 1.

[0078] Comparative Example 7

[0079] The process is largely the same as in Example 1, except for step S4. After the modified polyester is neutralized, a high-speed dispersion paddle is used at a speed of 800 r / min. Instead of adding water gradually in stages, deionized water is added rapidly all at once within 5 minutes, with the total amount of water added being the same as in Example 1. After the addition, the mixture is further dispersed at 800 r / min for 30 minutes to obtain the dispersion of Comparative Example 7. Except for the water addition time and method, the raw materials and conditions are the same as in Example 1.

[0080] Comparative Example 8

[0081] The process was largely the same as in Example 1, except that 48.0 g of single-ended dihydroxyl polydimethylsiloxane was used instead of 48.0 g of EP-PDMS. This single-ended dihydroxyl polydimethylsiloxane, model HY-2000, had an average molecular weight of 2000–2100, a hydroxyl equivalent of 1000–1050 g / eq, and a viscosity of 80–90 mPa·s at 25°C. Triphenylphosphine was not added in S3, and the carboxylated polyester was reacted with it at 115°C for 120 min. Then, P1 and P2 were added as in Example 1 to complete the neutralization and water dispersion in S4, yielding the dispersion of Comparative Example 8.

[0082] Performance testing

[0083] The solid content, average particle size, PDI, viscosity at 25°C, pH, agglomerate content, centrifugal stability, and stability at 50°C for 30 days were determined for the dispersions obtained in Examples 1-6 and Comparative Examples 1-8. The results are shown in Table 1.

[0084] After preparation, each sample was cooled to 25±2℃, sealed, and allowed to stand for 24 h. Before testing, it was slowly stirred at 200 r / min for 3 min. Except for particle size and PDI, which required dilution with deionized water, all other parameters were determined directly using the original dispersion without dilution or filtration. Solid content, average particle size, PDI, viscosity, pH, and agglomerate content were all measured in triplicate, and the average value was taken.

[0085] Solid content was determined by the loss on drying method: the sample was dried to constant weight at 105±2℃ and calculated using the following formula: Solid content = mass of residue after drying / initial mass of sample × 100%.

[0086] Average particle size and PDI were determined by dynamic light scattering, viscosity was determined by rotational viscometer, and pH was determined by calibrated pH meter. All three measurements were performed at 25±1℃.

[0087] The coagulant content was determined by filtration weighing: 100.0 g of sample was weighed and passed through a pre-weighed filter medium with a pore size of 100 μm. The retained material was dried to constant weight at 105±2℃ and calculated using the following formula: Agglomerate content = mass of dried retentate / initial mass of sample × 100%.

[0088] Centrifugal stability was evaluated by centrifuging a 20 mL sample at 3000 r / min for 30 min: if no obvious stratification, precipitation, separation or flocculation was observed, it was recorded as "stable"; otherwise, it was recorded according to the actual phenomenon.

[0089] The stability of the sample stored at 50℃ for 30 days was evaluated by placing the sample in a sealed glass bottle and storing it at 50±2℃ for 30 days. After storage, the sample was placed at 25±2℃ for 24 hours, and the presence of stratification, precipitation, oil separation, flocculation, abnormal thickening or gelation was observed and recorded according to the actual results.

[0090] Table 1. Performance test results of polyester dispersions in Examples 1-6 and Comparative Examples 1-8

[0091] As shown in Table 1, the dispersions obtained in Examples 1-6 had a solid content of 50.8-54.7 wt%, an average particle size of 113-141 nm, a PDI of 0.25-0.29, and a coagulant content of 0.06-0.12 wt%. They remained stable after centrifugation and storage at 50°C for 30 days. This demonstrates that even with this level of solid content, the dispersions remained uniformly dispersed and well-storable.

[0092] Comparative Example 1, where organopolysiloxane was added via physical mixing, showed significantly larger average particle size and agglomerate content, resulting in stratification and increased particle size after storage. Comparative Example 8, where a single-terminal dihydroxyl polydimethylsiloxane was used instead of a single-terminal epoxy group, also exhibited increased particle size and stratification. This indicates that only by grafting organopolysiloxane with carboxyl-containing branched linking groups can aggregation and phase separation be effectively suppressed.

[0093] Comparative Examples 2 and 3, each introducing only one phosphorus-containing compound, showed precipitation, increased viscosity, or increased particle size after storage, respectively. Comparative Examples 4 and 5, each using only one tertiary amine, also showed decreased storage stability. This indicates that the combined introduction of two types of phosphorus-containing structures and the combination of DMEA and TEA are necessary to maintain the particle size, viscosity, and storage stability of the dispersion.

[0094] Comparative Example 6 showed a low water dispersion speed, while Comparative Example 7 used a single, rapid water addition. The resulting dispersion exhibited significantly increased particle size, PDI, viscosity, and agglomerate content, along with precipitation or stratification. This indicates that a suitable stirring intensity, combined with phased, gradual water addition, is necessary for the modified polyester to uniformly complete its phase inversion and form a stable, high-solids system.

[0095] The above embodiments are only used to further illustrate the technical solution of the present invention and do not constitute a limitation on the scope of protection of the present invention. Without departing from the technical concept of the present invention, those skilled in the art can make appropriate adjustments to the specific types, proportions, and amounts of the basic polyol components, basic polyacid components, carboxyl-containing branched linking groups, organopolysiloxanes, phosphorus-containing compounds, and volatile tertiary amines, as well as the esterification polycondensation conditions, grafting reaction conditions, neutralization conditions, and water dispersion conditions, according to actual needs. All equivalent substitutions, conventional modifications, or non-substantial changes made based on the technical concept of the present invention should fall within the scope of protection of the present invention.

Claims

1. A long-lasting modified polyester dispersion, characterized in that, Including water, modified polyester, and volatile tertiary amines; Based on a total mass of 100 wt% of the long-acting modified polyester dispersion, the solid content of the long-acting modified polyester dispersion is 50-55 wt%, and the solid content is determined by the drying loss method at 105±2℃. When preparing the long-lasting modified polyester dispersion, based on a theoretical dry basis total mass of 100 wt% for the modified polyester, the amount of volatile tertiary amine fed is 0.6–3.2 wt%. Based on a theoretical dry basis total mass of 100 wt% for the modified polyester, and calculated according to the mass of the effective components of the raw materials used to form the corresponding structure, the modified polyester comprises 3.5–6.0 wt% organopolysiloxane segments, 2.0–5.0 wt% phosphorus-containing structural units, 1.5–4.0 wt% carboxyl-branched linking groups, and the balance being polyester segments; The organopolysiloxane segment is grafted onto the polyester segment via the carboxyl-containing branched linker group, and the phosphorus-containing structural unit is introduced into the modified polyester through a reaction.

2. The long-acting modified polyester dispersion according to claim 1, characterized in that, The polyester segments are formed by esterification and polycondensation reactions of basic polyol components and basic polyacid components. Based on a total feed mass of 100 wt% for the basic polyol component, the basic polyol component consists of 52-58 wt% neopentyl glycol and 42-48 wt% 1,4-cyclohexanediethanol. Based on a total feed mass of 100 wt% for the basic polybasic acid component, the basic polybasic acid component consists of 68-72 wt% isophthalic acid and 28-32 wt% hexahydrophthalic anhydride.

3. The long-acting modified polyester dispersion according to claim 1, characterized in that, The carboxyl-containing branched linker group is formed by the reaction of trimellitic anhydride with the hydroxyl groups in the polyester segment.

4. The long-lasting modified polyester dispersion according to claim 3, characterized in that, The organopolysiloxane segments are formed from single-terminated epoxy polydimethylsiloxane; At least some of the carboxyl groups in the carboxyl-containing branched linking group react with the epoxy groups in the single-terminal epoxy polydimethylsiloxane to form a β-hydroxy ester linking structure, and the modified polyester retains unreacted carboxyl groups.

5. The long-acting modified polyester dispersion according to claim 1, characterized in that, The phosphorus-containing structural unit is introduced by a reaction of a hydroxyalkylphosphonate compound and a hydroxyalkylphosphate monoester compound; Based on a total active ingredient content of 100 wt% for the hydroxyalkylphosphonate compound and the hydroxyalkylphosphate monoester compound, the active ingredient content of the hydroxyalkylphosphonate compound is 48-52 wt%, and the active ingredient content of the hydroxyalkylphosphate monoester compound is 48-52 wt%.

6. The long-lasting modified polyester dispersion according to claim 1, characterized in that, The volatile tertiary amine is composed of dimethylethanolamine and triethylamine; Based on a total mass of 100 wt% of the volatile tertiary amines, the amount of dimethylethanolamine is 52-58 wt%, and the amount of triethylamine is 42-48 wt%.

7. The long-lasting modified polyester dispersion according to any one of claims 1 to 6, characterized in that, The long-lasting modified polyester dispersion, measured by dynamic light scattering at 25±1℃, has an average particle size of no more than 150 nm and a PDI of no more than 0.30; using a filter medium with a pore size of 100 μm, the agglomerate content, measured by gravimetric analysis, is no more than 0.15 wt%. The long-lasting modified polyester dispersion was loaded into a sealed glass container, with the loading amount being 80±5% of the effective volume of the sealed glass container. After being stored at 50±2℃ for 30 days and placed at 25±2℃ for 24 hours, no visible layering, precipitation, oil separation, flocculation or gelation was observed.

8. A method for preparing a long-lasting modified polyester dispersion according to any one of claims 1 to 6, characterized in that, The steps include the following: S1. The basic polyol component and the basic polyacid component are subjected to esterification and polycondensation reaction to obtain a hydroxyl-containing basic polyester. S2. React trimellitic anhydride with the hydroxyl groups in the base polyester to obtain a carboxylated polyester containing carboxyl branched linkage groups. S3. First, react the carboxylated polyester with a single-terminated epoxy polydimethylsiloxane, then add a hydroxyalkylphosphonate compound and a hydroxyalkylphosphate monoester compound to react and obtain a modified polyester containing organopolysiloxane segments and phosphorus-containing structural units. S4. Add volatile tertiary amine to the modified polyester for neutralization, and gradually add water under high-speed mechanical stirring to cause the system to reverse and form a uniform long-lasting modified polyester dispersion; control the amount of water added so that the solid content of the obtained long-lasting modified polyester dispersion is 50-55 wt%.

9. The method for preparing the long-lasting modified polyester dispersion according to claim 8, characterized in that: In step S1, the temperature of the esterification reaction is 160–195°C, and the temperature of the polycondensation reaction is 195–225°C. In step S2, the base polyester is cooled to 130-170°C and then trimellitic anhydride is added to carry out the reaction. In step S3, the carboxylated polyester is reacted with the single-terminated epoxy polydimethylsiloxane at 100–140°C, and then the hydroxyalkylphosphonate compound and the hydroxyalkylphosphate monoester compound are added at 120–140°C to carry out the reaction. In step S4, the modified polyester is cooled to 55-85°C and then neutralized with the volatile tertiary amine. Water is then gradually added under high-speed mechanical stirring at 600-1200 r / min for dispersion.

10. The method for preparing the long-lasting modified polyester dispersion according to claim 9, characterized in that, In step S4, based on the theoretical dry basis total mass of the modified polyester as 100 wt%, the initial water addition rate is 0.5 to 1.0 wt% / min; after the reaction system undergoes phase reversal and forms a uniform aqueous dispersion, the water addition rate is increased to 2.0 to 3.0 wt% / min. After the system has completed its phase reversal and formed a uniform aqueous dispersion, continue high-speed mechanical stirring for 20–40 min.

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