Aliphatic amphiphilic dendritic polyester, preparation method therefor and use thereof

Abstract

Disclosed are an aliphatic amphiphilic dendritic polyester, a preparation method therefor and an application thereof, wherein the polyester comprises 60-100 parts by weight of a polyester polyol and 0-40 parts by weight of a solvent, and the polyester polyol comprises the following segments: a first segment provided by a polyol component I having high functionality, a second segment provided by an anhydride compound and a third segment provided by a polyol component II having a molecular weight of < 500. The polyester polyol has an OH value of greater than or equal to 115 KOH mg / g and an acid value of greater than or equal to 50 KOH mg / g and less than or equal to 290 KOH mg / g, and the molar ratio of the anhydride compound to the polyol component I having high functionality is 3-6, wherein the average functionality of the polyol component I having high functionality is greater than or equal to 3.

Description

An aliphatic amphiphilic dendritic polyester, its preparation method and application Technical Field

[0001] This invention belongs to the field of coating resin technology, specifically relating to an aliphatic amphiphilic dendritic polyester. This invention further relates to the preparation method of the aforementioned aliphatic amphiphilic dendritic polyester and its application in automotive clear coats. Background Technology

[0002] With the rapid development of the social economy, my country's per capita car ownership has continued to grow, and the demand for various automotive products has also increased accordingly. In the field of automotive coatings, coatings not only give the car body an excellent visual effect, but also serve as a protective barrier, effectively resisting corrosion from various external chemical media. Among them, the clear coat layer of a car, as the first line of defense against external erosion, is of great significance in improving the vehicle's resistance to chemical media.

[0003] In automotive coatings applications, especially in the field of automotive refinish paints, clear coats not only need to have excellent appearance but also require faster drying speeds. However, current automotive coatings often cannot simultaneously meet the requirements of rapid drying and excellent appearance. Typically, if the coating dries too quickly, its leveling properties will be affected, resulting in poor gloss and fullness, thus impacting the final appearance. Conversely, to achieve a good appearance, a longer leveling time is usually required, which significantly reduces the drying speed and affects application efficiency.

[0004] To address this technical challenge, researchers typically improve coating performance by optimizing the combination of resins, curing agents, catalysts, and solvents. Generally, the chemical resistance of a coating is closely related to the crosslinking density of the resin, while good leveling properties are essential for achieving excellent appearance. Simultaneously, rapid drying requires the resin to possess a multifunctional macromolecular structure. Therefore, employing compact macromolecules, such as hyperbranched or dendritic compounds, has become an effective approach to improving coating performance.

[0005] Dendritic polymers are a class of nonlinear polymers with highly branched structures and a large number of modifiable end groups. By controlling and designing the size, shape, structure and functional units of molecules at the molecular level, special properties that traditional linear polymers do not possess can be obtained. However, traditional dendritic polymers have the following drawbacks in practical applications: (1) They are usually prepared using AB2 or AB3 branched structural units, but the polymerization process is difficult to control completely, which can easily increase the polymer radius size, resulting in a relatively loose structure, which in turn results in low solid content and high viscosity, affecting coating performance; (2) Traditional dendritic polymers have low acid values ​​and high hydroxyl values, which leads to their lack of water solubility. They need to be dissolved in organic solvents before mixing and use, which limits their application in water-based coatings.

[0006] The aforementioned problems severely limit the widespread application of dendritic polymers in automotive coatings. Therefore, there is an urgent need to develop novel dendritic polymers that simultaneously meet the requirements of rapid drying and excellent appearance, thereby expanding their application in waterborne coatings.

[0007] Summary of the Invention

[0008] This invention provides an aliphatic amphiphilic dendritic polyester, its preparation method, and its application in automotive clear coat. The provided aliphatic amphiphilic dendritic polyester can simultaneously meet the requirements of rapid drying and excellent appearance.

[0009] The technical solution of the present invention is as follows:

[0010] An aliphatic amphiphilic dendritic polyester, said polyester comprising 60-100 parts by weight of a polyester polyol and 0-40 parts by weight of a solvent, wherein said polyester polyol comprises the following segments:

[0011] The first segment is provided by polyol component I with high functionality;

[0012] The second segment is provided by anhydride compounds;

[0013] The third segment is provided by polyol component II with a molecular weight <500;

[0014] in,

[0015] The OH value of the polyester polyol is ≥115 KOH mg / g;

[0016] The acid value of the polyester polyol is greater than or equal to 50 KOH mg / g and less than or equal to 290 KOH mg / g;

[0017] The molar ratio of the acid anhydride compound to the high-functionality polyol component I is 3-6, wherein the average functionality of the high-functionality polyol component I is greater than or equal to 3.

[0018] In this invention, the OH value of the polyester polyol refers to the value tested according to ISO 4629-3. The acid value of the polyester polyol refers to the value tested according to GB / T 6743.

[0019] The polyester polyol has a spherical structure, wherein the first segment is the center, the second segment is the core, and the third segment is the shell.

[0020] In this invention, the hydroxyl value of the polyester polyol is limited to greater than 115, which can achieve the technical effect of improving the coating's durability.

[0021] The present invention limits the molecular weight of polyol component II to less than 500 because a molecular weight that is too high will lead to an increase in resin viscosity, making it impossible to achieve the technical effect of high solids and low viscosity.

[0022] In this invention, the functionality of polyol component II is greater than or equal to 2.

[0023] This invention limits the acid value of polyester polyols, and an appropriate acid value imparts excellent hydrophilicity to polyester.

[0024] In embodiments of the present invention, based on a total weight of 100 parts of aliphatic amphiphilic dendritic polyester, the solvent content is 0-40 parts, the polyester polyol content is 60-100 parts, and wherein the content of high-functionality polyol component I is 6-22 parts, the content of acid anhydride compound is 28-67 parts, and the content of polyol component II with a molecular weight <500 is 13-53 parts. All contents mentioned here refer to weight content.

[0025] In some embodiments of the present invention, the high-functionality polyol component I is selected from at least one of sorbitol, pentaerythritol, xylitol, maltitol, inositol, mannitol, glucose, trimethylolpropane, trimethylolethane, glycerol, arabinitol, trimethylolaminomethane, triethanolamine, and β-hydroxyalkylamide.

[0026] In some embodiments of the present invention, the acid anhydride compound is selected from at least one of hexahydrophthalic anhydride, acetic anhydride, succinic anhydride, maleic anhydride, isohydrin, trichloroacetic anhydride, trifluoroacetic anhydride, adipic anhydride, tetrahydrophthalic anhydride, and maleic anhydride.

[0027] In some embodiments of the present invention, the polyol component II with a molecular weight <500 is selected from at least one of sorbitol, pentaerythritol, xylitol, maltitol, inositol, mannitol, glucose, trimethylolpropane, trimethylolethane, glycerol, arabinitol, trimethylolaminomethane, triethanolamine, ethylene glycol, propylene glycol, butanediol, dimethyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-hydroxy-2,2-dimethyl-3-hydroxy-2,2-dimethylpropylpropionate, 1,4-cyclohexanediol, trimethylpentanediol, HAA-β-hydroxyalkylamide, isosorbide, 1,2,6-hexanetriol, and hydrogenated bisphenol A.

[0028] The solvent may be selected from at least one of butyl acetate, xylene, dipropylene glycol methyl ether, propylene glycol methyl ether acetate, propylene glycol methyl ether, 1,3,5-trimethylbenzene, and 1,2,4-trimethylbenzene.

[0029] The present invention also provides a method for preparing the aforementioned aliphatic amphiphilic dendritic polyester, the method comprising the following steps:

[0030] 1) Add the high-functionality polyol component I to the reaction apparatus, slowly heat to 100-130℃, and stir for 0.5-2 hours;

[0031] 2) Add the acid anhydride compound dropwise to the reaction solution prepared in step 1), and slowly heat to 120-160°C to react. Test the acid value at predetermined time intervals until the theoretical acid value is reached.

[0032] 3) Add the polyol component II with a molecular weight <500 to the reaction solution prepared in step 2). After the addition is complete, heat the solution to 150-200°C at a rate of 8-12°C / hour and keep it at that temperature. Test the acid value at predetermined intervals until the target acid value is reached.

[0033] 4) Cool the reaction solution prepared in step 3) to 100-120℃ and dehydrate it under vacuum pressure of -0.05 to -0.1 MPa for 0.5-2 hours;

[0034] 5) Cool the reaction solution prepared in step 4) to 80-110°C, add 0-40 parts by weight of the solvent, stir evenly, cool to below 70-90°C, and filter out the material.

[0035] In steps 1) and 2), slow heating can refer to heating over a period of one hour or more to avoid explosive polymerization.

[0036] The solvent is selected from at least one of butyl acetate, xylene, dipropylene glycol methyl ether, propylene glycol methyl ether acetate, propylene glycol methyl ether, 1,3,5-trimethylbenzene, and 1,2,4-trimethylbenzene.

[0037] In the above methods, the acid value is tested according to GB / T 6743.

[0038] In step 3) above, after adding polyol component II, the temperature is increased to 150-200℃ at a rate of 10℃ / hour and maintained at that temperature.

[0039] In steps 2) and 3) above, the predetermined time interval is 1 hour.

[0040] In the above methods, the reaction apparatus can be a stirring apparatus equipped with a stirrer and a thermometer.

[0041] In the above method, the theoretical acid value is calculated as follows: ((amount of acid anhydride compound * functionality - high-functionality polyol component I * functionality)) * 56100 / (mass of acid anhydride compound + mass of high-functionality polyol component I).

[0042] In the above methods, the target acid value refers to a value greater than or equal to 50 KOH mg / g and less than or equal to 290 KOH mg / g.

[0043] The present invention also provides an automotive clear coat comprising any of the aforementioned aliphatic amphiphilic dendritic polyesters.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] 1. The product has lower viscosity and higher solid content: The aliphatic amphiphilic dendritic polyester proposed in this invention optimizes the molecular structure by selecting more flexible aliphatic raw materials and obtains a more compact polymer structure through the ring-opening nucleation method of acid anhydride and high-functionality polyol, thereby minimizing the polymer on a two-dimensional scale, significantly reducing the viscosity of the polyester, and increasing the solid content, which is superior to polyester products in the prior art.

[0046] 2. Achieving amphiphilicity in resin-like polyester: The aliphatic amphiphilic dendritic polyester of this invention achieves amphiphilicity by introducing specific carboxylic acids (i.e., acid anhydrides) and polyols. It is suitable for both oil-based and water-based coating systems, expanding the application range of polyester and showing significant advantages over dendritic polyesters in the prior art.

[0047] 3. Improved chemical resistance of automotive clear coat: The aliphatic amphiphilic dendritic polyester in this invention uses a precisely controlled polymerization process (including the selection of temperature in each step of the reaction, control of acid anhydride addition, and control of target acid value), which improves the structural compactness and crosslinking density of the polyester, thereby significantly improving the chemical resistance of automotive clear coat, which is superior to existing polyester products.

[0048] 4. Improvement of the incompatibility between appearance and drying speed: This invention improves the branching degree and introduces a large number of hydroxyl groups by selecting high-functionality polyols and combining them with the process (by grafting polyols onto high-functionality polyols with anhydride end-capping). This achieves the goal of improving the leveling and gloss of automotive coatings while ensuring rapid drying speed, thus resolving the contradiction between the appearance and drying speed of automotive coatings in the prior art and providing a more balanced coating effect.

[0049] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Detailed Implementation

[0050] This invention provides an aliphatic amphiphilic dendritic polyester, wherein the polyester comprises 60-100 parts by weight of a polyester polyol and 0-40 parts by weight of a solvent, wherein the polyester polyol comprises the following segments:

[0051] The first segment is provided by polyol component I with high functionality;

[0052] The second segment is provided by anhydride compounds;

[0053] The third segment is provided by polyol component II with a molecular weight <500;

[0054] in,

[0055] The OH value of the polyester polyol is ≥115 KOH mg / g;

[0056] The acid value of the polyester polyol is greater than or equal to 50 KOH mg / g and less than or equal to 290 KOH mg / g;

[0057] The molar ratio of the acid anhydride compound to the high-functionality polyol component I is 3-6, wherein the average functionality of the high-functionality polyol component I is greater than or equal to 3.

[0058] In this invention, the OH value of the polyester polyol refers to the value tested according to ISO 4629-3. The acid value of the polyester polyol refers to the value tested according to GB / T 6743.

[0059] The polyester polyol of the present invention has a spherical structure, wherein the first segment is the center of the sphere, the second segment is the core of the sphere, and the third segment is the shell of the sphere.

[0060] In this invention, the functionality of polyol component II is greater than or equal to 2.

[0061] In embodiments of the present invention, based on a total weight of 100 parts of aliphatic amphiphilic dendritic polyester, the solvent content is 0-40 parts, the polyester polyol content is 60-100 parts, and wherein the content of high-functionality polyol component I is 6-22 parts, the content of acid anhydride compound is 28-67 parts, and the content of polyol component II with a molecular weight <500 is 13-53 parts. All contents mentioned here refer to weight content.

[0062] In some embodiments of the present invention, the high-functionality polyol component I is selected from at least one of sorbitol, pentaerythritol, xylitol, maltitol, inositol, mannitol, glucose, trimethylolpropane, trimethylolethane, glycerol, arabinitol, trimethylolaminomethane, triethanolamine, and β-hydroxyalkylamide.

[0063] In some embodiments of the present invention, the acid anhydride compound is selected from at least one of hexahydrophthalic anhydride, acetic anhydride, succinic anhydride, maleic anhydride, isohydrin, trichloroacetic anhydride, trifluoroacetic anhydride, adipic anhydride, tetrahydrophthalic anhydride, and maleic anhydride.

[0064] In some embodiments of the present invention, the polyol component II with a molecular weight <500 is selected from at least one of sorbitol, pentaerythritol, xylitol, maltitol, inositol, mannitol, glucose, trimethylolpropane, trimethylolethane, glycerol, arabinitol, trimethylolaminomethane, triethanolamine, ethylene glycol, propylene glycol, butanediol, dimethyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-hydroxy-2,2-dimethyl-3-hydroxy-2,2-dimethylpropylpropionate, 1,4-cyclohexanediol, trimethylpentanediol, HAA-β-hydroxyalkylamide, isosorbide, 1,2,6-hexanetriol, and hydrogenated bisphenol A.

[0065] The solvent may be selected from at least one of butyl acetate, xylene, dipropylene glycol methyl ether, propylene glycol methyl ether acetate, propylene glycol methyl ether, 1,3,5-trimethylbenzene, and 1,2,4-trimethylbenzene.

[0066] The present invention also provides a method for preparing the aforementioned aliphatic amphiphilic dendritic polyester, the method comprising the following steps:

[0067] 1) Add the high-functionality polyol component I to the reaction apparatus, slowly heat to 100-130℃, and stir for 0.5-2 hours;

[0068] 2) Add the acid anhydride compound dropwise to the reaction solution prepared in step 1), and slowly heat to 120-160°C to react. Test the acid value at predetermined time intervals until the theoretical acid value is reached.

[0069] 3) Add the polyol component II with a molecular weight <500 to the reaction solution prepared in step 2). After the addition is complete, heat the solution to 150-200°C at a rate of 8-12°C / hour and keep it at that temperature. Test the acid value at predetermined intervals until the target acid value is reached.

[0070] 4) Cool the reaction solution prepared in step 3) to 100-120℃ and dehydrate it under vacuum pressure of -0.05 to -0.1 MPa for 0.5-2 hours;

[0071] 5) Cool the reaction solution prepared in step 4) to 80-110°C, add 0-40 parts by weight of the solvent, stir evenly, cool to below 70-90°C, and filter out the material.

[0072] This invention has the following characteristics compared to traditional dendritic polyesters:

[0073] (1) Reduce the viscosity of dendritic polyester and increase the solid content

[0074] Traditional dendritic polyester polymerization processes are uncontrollable, resulting in longer molecular chains, larger polymer radii, and a looser structure, thus exhibiting high viscosity and low solids content.

[0075] This invention utilizes aliphatic raw materials to make the polyester structure more flexible, thereby effectively reducing viscosity. Furthermore, the invention employs a polymerization process involving ring-opening nucleation of acid anhydrides and high-functionality polyols, reducing side reactions, forming a more compact molecular structure, decreasing the molecular radius, and achieving lower viscosity and higher solids content.

[0076] (2) Enhance the amphiphilicity of dendritic polyester

[0077] Traditional dendritic polyesters, due to their low acid value, high hydroxyl value, and high branching degree, exhibit strong oleophilicity but poor hydrophilicity, which limits their application in water-based coatings.

[0078] This invention introduces a certain proportion of carboxylic acid, and the neutralized carboxylic acid ions can make dendritic polyesters hydrophilic, so that the polyesters have both oleophilic and hydrophilic properties, ensuring that they can be used in both oil-based and water-based coatings, thus broadening their application range.

[0079] (3) Improve the chemical resistance of automotive clear coat.

[0080] Currently, conventional automotive clear coats lack sufficient resistance to chemical media such as engine oil, gasoline, acid, alkali, and water, which affects the service life and durability of the coating.

[0081] This invention employs a ring-opening nucleation polymerization process involving acid anhydrides and highly functional polyols, which enables controllable polymer structure, thereby obtaining a more compact branched structure and a higher hydroxyl value, which in turn increases the crosslinking density and significantly improves the chemical resistance of automotive clear coats.

[0082] (4) Balancing the appearance and drying speed of automotive clear coat

[0083] Currently, conventional automotive clear coats often struggle to achieve both fast drying speed and excellent appearance. Fast drying results in poor leveling, low gloss, and low fullness, while coatings with excellent appearance often require a longer leveling time.

[0084] This invention reduces the viscosity of polyester through a polymerization process involving the ring-opening nucleation of aliphatic raw materials and acid anhydrides with highly functional polyols, thereby improving the leveling properties of the coating. Simultaneously, by increasing the degree of branching and introducing a large number of hydroxyl groups, the drying speed of the coating is increased, thus achieving a superior coating appearance while ensuring rapid drying.

[0085] In this document, the range expressed as "from one value to another" is a concise way of representing a range to avoid listing all the values ​​in that range in the specification. Therefore, the description of a particular range of values ​​covers any value within that range as well as the smaller range of values ​​defined by that value, just as if the arbitrary value and the smaller range of values ​​were explicitly stated in the specification.

[0086] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Improvements and adjustments made by those skilled in the art based on the present invention in practical applications shall still fall within the scope of protection of the present invention.

[0087] In the following Examples 1-10, the total mass content of the produced aliphatic amphiphilic dendritic polyester is calculated as 100 parts.

[0088] Example 1

[0089] Add pentaerythritol (high-functionality polyol component I, mass content 8.15 parts) to a reaction vessel equipped with a stirrer and thermometer, slowly raise the temperature to 110℃, and maintain it at 110±2℃ for 0.5h. After the holding time, add hexahydrophthalic anhydride (acid anhydride compound, mass content 37.4 parts) dropwise to the reaction solution. After that, slowly raise the temperature to 140±2℃ and hold it. Test the acid value every hour according to GB / T 6743. The reaction proceeds until the theoretical acid value is reached (theoretical acid value: 290-300mgKOH / g). After the acid value is qualified, add pentaerythritol (polyol component II with molecular weight <500, mass content 24.45 parts) to the reaction vessel. Then gradually raise the temperature by 10℃ / hour to 170±2℃ and hold it. Test the acid value every hour according to GB / T 6743 until the target acid value of 50-55mgKOH / g is reached. After the acid value meets the requirements, the temperature is lowered to 115±2℃, and dehydration is carried out under vacuum pressure of -0.05~-0.1Mpa for 2 hours. After completion, the temperature is lowered to 115±2℃, butyl acetate (solvent, 30 parts by mass) is added, stirred evenly, and then cooled to below 70℃ and filtered out. An aliphatic amphiphilic dendritic polyester is obtained.

[0090] Example 2

[0091] Glycerol (high-functionality polyol component I, mass content 8.66 parts) was added to a reaction vessel equipped with a stirrer and thermometer. The temperature was slowly raised to 110℃ and maintained at 110±2℃ for 0.5 hours. After the holding time, hexahydrophthalic anhydride (acid anhydride compound, mass content 44.03 parts) was added dropwise to the reaction solution. The temperature was then slowly raised to 140±2℃ and held. The acid value was tested every hour according to GB / T 6743. The reaction proceeded until the theoretical acid value was reached (theoretical acid value: 200-210 mgKOH / g). After the acid value was qualified, glycerol (polyol component II, mass content <500 molecular weight, mass content 17.31 parts) was added to the reaction vessel. The temperature was then gradually raised to 170±2℃ at a rate of 10℃ / hour and held. The acid value was tested every hour according to GB / T 6743 until the target acid value of 52-57 mgKOH / g was reached. After the acid value meets the requirements, the temperature is lowered to 115±2℃, and dehydration is carried out under vacuum pressure of -0.05~-0.1Mpa for 2 hours. After completion, the temperature is lowered to 90±2℃, butyl acetate (solvent, mass content 30 parts) is added, stirred evenly, and then cooled to below 70℃ and filtered out. Aliphatic amphiphilic dendritic polyester is obtained.

[0092] Example 3

[0093] Pentaerythritol (high-functionality polyol component I, mass content 8.25 parts) was added to a reaction vessel equipped with a stirrer and thermometer. The temperature was slowly raised to 110℃ and maintained at 110±2℃ for 0.5 hours. After the holding period, tetrahydrophthalic anhydride (acid anhydride compound, mass content 37.37 parts) was added dropwise to the reaction solution. The temperature was then slowly raised to 140±2℃ and held. The acid value was tested every hour according to GB / T 6743. The reaction proceeded until the theoretical acid value was reached (theoretical acid value: 298-308 mgKOH / g). After the acid value was qualified, trimethylolpropane (polyol component II, molecular weight <500, mass content 24.38 parts) was added to the reaction vessel. The temperature was then gradually raised to 170±2℃ at a rate of 10℃ / hour and held. The acid value was tested every hour according to GB / T 6743 until the target acid value of 51-56 mgKOH / g was reached. After the acid value meets the requirements, the temperature is lowered to 115±2℃, and dehydration is carried out under vacuum pressure of -0.05 to -0.1 MPa for 2 hours. After completion, the temperature is lowered to 105±2℃, xylene (solvent, 15 parts by mass) and butyl acetate (solvent, 15 parts by mass) are added, stirred evenly, and then cooled to below 70℃. The product is then filtered out. An aliphatic amphiphilic dendritic polyester is obtained.

[0094] Example 4

[0095] Pentaerythritol (high-functionality polyol component I, mass content 6.53 parts) was added to a reaction vessel equipped with a stirrer and thermometer. The temperature was slowly raised to 110℃ and maintained at 110±2℃ for 0.5 hours. After the holding period, tetrahydrophthalic anhydride (acid anhydride compound, mass content 43.85 parts) was added dropwise to the reaction solution. The temperature was then slowly raised to 140±2℃ and held. The acid value was tested every hour according to GB / T 6743. The reaction proceeded until the theoretical acid value was reached (theoretical acid value: 428-438 mgKOH / g). After the acid value was qualified, pentaerythritol (polyol component II with molecular weight <500, mass content 19.62 parts) was added to the reaction vessel. The temperature was then gradually raised to 170±2℃ at a rate of 10℃ / hour and held. The acid value was tested every hour according to GB / T 6743 until the target acid value of 200-205 mgKOH / g was reached. After the acid value meets the requirements, the temperature is lowered to 115±2℃, and dehydration is carried out under vacuum pressure of -0.05~-0.1Mpa for 2 hours. After completion, the temperature is lowered to 90±2℃, butyl acetate (solvent, mass content 30 parts) is added, stirred evenly, and then cooled to below 70℃ and filtered out. Aliphatic amphiphilic dendritic polyester is obtained.

[0096] Example 5

[0097] Trimethylolpropane (high-functionality polyol component I, mass content 9.40 parts) was added to a reaction vessel equipped with a stirrer and thermometer. The temperature was slowly raised to 110℃ and maintained at 110±2℃ for 0.5h. After the holding time was completed, tetrahydrophthalic anhydride (acid anhydride compound, mass content 31.98 parts) was added dropwise to the reaction solution. After the holding time was completed, the temperature was slowly raised to 140±2℃ and maintained. The acid value was tested every 1 hour according to GB / T 6743. The reaction was considered qualified after the theoretical acid value was reached (theoretical acid value: 285-295mgKOH / g). After the acid value is deemed acceptable, 3-hydroxy-2,2-dimethyl-3-hydroxy-2,2-dimethylpropylpropionate (polyol component II with a molecular weight <500, mass content 28.62 parts) is added to the reactor; then the temperature is gradually increased to 170±2℃ at 10℃ / hour and held, with the acid value tested every hour according to GB / T 6743 until the target acid value of 58-63 mgKOH / g is reached. After the acid value is deemed acceptable, the temperature is lowered to 115±2℃, and dehydration is performed under vacuum pressure of -0.05~-0.1Mpa for 2 hours. After completion, the temperature is lowered to 90±2℃, butyl acetate (solvent, mass content 30 parts) is added, stirred evenly, and then cooled to below 70℃ and filtered out. An aliphatic amphiphilic dendritic polyester is obtained.

[0098] Example 6

[0099] Add pentaerythritol (high-functionality polyol component I, mass content 10.17 parts) to a reactor equipped with a stirrer and thermometer, slowly raise the temperature to 110℃, and maintain it at 110±2℃ for 0.5h. After the holding time, add maleic anhydride (an acid anhydride compound, mass content 29.31 parts) dropwise to the reaction solution. After that, slowly raise the temperature to 140±2℃ and hold it. Test the acid value every hour according to GB / T 6743. The reaction proceeds until the theoretical acid value is reached (theoretical acid value: 425-435 mgKOH / g). After the acid value is qualified, add pentaerythritol (polyol component II with molecular weight <500, mass content 30.52 parts) to the reactor. Then gradually raise the temperature by 10℃ / hour to 170±2℃ and hold it. Test the acid value every hour according to GB / T 6743 until the target acid value is reached (target acid value 64-69 mgKOH / g). After the acid value meets the requirements, the temperature is lowered to 115±2℃, and dehydration is carried out under vacuum pressure of -0.05~-0.1Mpa for 2 hours. After completion, the temperature is lowered to 90±2℃, butyl acetate (solvent, mass content 30 parts) is added, stirred evenly, and then cooled to below 70℃ and filtered out. Aliphatic amphiphilic dendritic polyester is obtained.

[0100] Example 7

[0101] Add pentaerythritol (high-functionality polyol component I, mass content 20.48 parts) to a reaction vessel equipped with a stirrer and thermometer, slowly raise the temperature to 110℃, and maintain it at 110±2℃ for 0.5h. After the holding time, add maleic anhydride (an acid anhydride compound, mass content 59.04 parts) dropwise to the reaction solution. After that, slowly raise the temperature to 140±2℃ and hold it. Test the acid value every hour according to GB / T 6743. The reaction proceeds until the theoretical acid value is reached (theoretical acid value: 425-435 mgKOH / g). After the acid value is qualified, add pentaerythritol (polyol component II with molecular weight <500, mass content 20.48 parts) to the reaction vessel. Then gradually raise the temperature by 10℃ / hour to 170±2℃ and hold it. Test the acid value every hour according to GB / T 6743 until the target acid value is reached (target acid value 261-266 mgKOH / g). After the acid value meets the requirements, the temperature is lowered to 115±2℃, and dehydration is carried out under vacuum pressure of -0.05~-0.1Mpa for 2 hours. After completion, the temperature is lowered to below 90℃, and the material is filtered out. Aliphatic amphiphilic dendritic polyester is obtained.

[0102] Example 8

[0103] Glycerol (high-functionality polyol component I, mass content 20.54 parts) was added to a reaction vessel equipped with a stirrer and thermometer. The temperature was slowly raised to 110℃ and maintained at 110±2℃ for 0.5 hours. After the holding time, maleic anhydride (an anhydride compound, mass content 65.63 parts) was added dropwise to the reaction solution. The temperature was then slowly raised to 140±2℃ and held. The acid value was tested every hour according to GB / T 6743. The reaction proceeded until the theoretical acid value was reached (theoretical acid value: 436-446 mgKOH / g). After the acid value was qualified, ethylene glycol (polyol component II, molecular weight <500, mass content 13.83 parts) was added to the reaction vessel. The temperature was then gradually raised to 170±2℃ at a rate of 10℃ / hour and held. The acid value was tested every hour according to GB / T 6743 until the target acid value of 261-266 mgKOH / g was reached. After the acid value meets the requirements, the temperature is lowered to 115±2℃, and dehydration is carried out under vacuum pressure of -0.05~-0.1Mpa for 2 hours. After completion, the temperature is lowered to below 90℃, and the material is filtered out. Aliphatic amphiphilic dendritic polyester is obtained.

[0104] Example 9

[0105] Glycerol (high-functionality polyol component I, mass content 6.67 parts) was added to a reaction vessel equipped with a stirrer and thermometer. The temperature was slowly raised to 110℃ and maintained at 110±2℃ for 0.5 hours. After the holding time, hexahydrophthalic anhydride (acid anhydride compound, mass content 33.91 parts) was added dropwise to the reaction solution. The temperature was then slowly raised to 140±2℃ and held. The acid value was tested every hour according to GB / T 6743. The reaction proceeded until the theoretical acid value was reached (theoretical acid value: 301-311 mgKOH / g). After the acid value was qualified, trimethylolpropane (polyol component II, mass content 19.42 parts) was added to the reaction vessel. The temperature was then gradually raised to 170±2℃ at a rate of 10℃ / hour and held. The acid value was tested every hour according to GB / T 6743 until the target acid value of 71-76 mgKOH / g was reached. After the acid value meets the requirements, the temperature is lowered to 115±2℃, and dehydration is carried out under vacuum pressure of -0.05~-0.1Mpa for 2 hours. After completion, the temperature is lowered to 90±2℃, butyl acetate (solvent, mass content 30 parts) is added, stirred evenly, and then cooled to below 70℃ and filtered out. Aliphatic amphiphilic dendritic polyester is obtained.

[0106] Example 10

[0107] Glycerol (high-functionality polyol component I, mass content 11.59 parts) was added to a reaction vessel equipped with a stirrer and thermometer. The temperature was slowly raised to 110℃ and maintained at 110±2℃ for 0.5 hours. After the holding time, maleic anhydride (an anhydride compound, mass content 37.03 parts) was added dropwise to the reaction solution. The temperature was then slowly raised to 140±2℃ and held. The acid value was tested every hour according to GB / T 6743. The reaction proceeded until the theoretical acid value was reached (theoretical acid value: 436-446 mgKOH / g). After the acid value was qualified, pentaerythritol (polyol component II, molecular weight <500, mass content 51.38 parts) was added to the reaction vessel. The temperature was then gradually raised to 170±2℃ at a rate of 10℃ / hour and held. The acid value was tested every hour according to GB / T 6743 until the target acid value of 76-81 mgKOH / g was reached. After the acid value meets the requirements, the temperature is lowered to 115±2℃, and dehydration is carried out under vacuum pressure of -0.05~-0.1Mpa for 2 hours. After completion, the temperature is lowered to below 90℃, and the material is filtered out. Aliphatic amphiphilic dendritic polyester is obtained.

[0108] Comparative Example 1

[0109] The difference from Example 1 is that the anhydride compound in Comparative Example 1 is an aromatic chemical raw material.

[0110] Pentaerythritol (high-functionality polyol component I, mass content 8.37 parts) was added to a reaction vessel equipped with a stirrer and thermometer. The temperature was slowly raised to 110℃ and maintained at 110±2℃ for 0.5 hours. After the holding period, phthalic anhydride (acid anhydride compound, mass content 35.48 parts) was added dropwise to the reaction solution. The temperature was then slowly raised to 140±2℃ and held. The acid value was tested every hour according to GB / T 6743. The reaction proceeded until the theoretical acid value was reached (theoretical acid value: 308-318 mgKOH / g). After the acid value was qualified, pentaerythritol (polyol component II with molecular weight <500, mass content 25.14 parts) was added to the reaction vessel. The temperature was then gradually raised to 170±2℃ at a rate of 10℃ / hour and held. The acid value was tested every hour according to GB / T 6743 until the target acid value of 52-57 mgKOH / g was reached. After the acid value meets the requirements, the temperature is lowered to 115±2℃, and dehydration is carried out under vacuum pressure of -0.05~-0.1Mpa for 2 hours. After completion, the temperature is lowered to 90±2℃, butyl acetate (solvent, mass content 30 parts) is added, stirred evenly, and then cooled to below 70℃ and filtered out. Dendritic polyester is obtained.

[0111] Comparative Example 2

[0112] The difference from Example 2 is that the preparation method described in Comparative Example 2 uses a conventional polymerization process.

[0113] Hexahydrophthalic anhydride (an acid anhydride compound, 44.03 parts by mass) was added to a reaction vessel equipped with a stirrer and thermometer. The temperature was slowly raised to 110℃ and maintained at 110±2℃ for 0.5 hours. After the holding time, glycerol (a high-functionality polyol component I, 25.97 parts by mass) was added dropwise to the reaction solution. After this, the temperature was slowly raised to 140±2℃ and held for 1 hour, then gradually increased to 170±2℃ at a rate of 10℃ / hour and held. The acid value was tested every hour according to GB / T 6743 until the target acid value of 79-84 mgKOH / g was reached. After the acid value was qualified, the temperature was lowered to 115±2℃ and dehydrated under a vacuum pressure of -0.05 to -0.1 MPa for 2 hours. After this, the temperature was lowered to 90±2℃, butyl acetate (solvent, 30 parts by mass) was added, stirred evenly, and then cooled to below 70℃. The mixture was then filtered out. Dendritic polyester was obtained.

[0114] Comparative Example 3

[0115] The difference from Example 3 is that the dendritic polyester prepared in Comparative Example 3 has an acid value of less than or equal to 10.

[0116] Pentaerythritol (high-functionality polyol component I, mass content 7.82 parts) was added to a reaction vessel equipped with a stirrer and thermometer. The temperature was slowly raised to 110℃ and maintained at 110±2℃ for 0.5h. After the holding time, tetrahydrophthalic anhydride (acid anhydride compound, mass content 35.46 parts) was added dropwise to the reaction solution. After that, the temperature was slowly raised to 140±2℃ and held. The acid value was tested every hour according to GB / T 6743. The reaction proceeded until the theoretical acid value was reached (theoretical acid value: 425-435 mgKOH / g). After the acid value was qualified, xylene (solvent, mass content 15 parts), trimethylolpropane (polyol component II, mass content 23.14 parts), and ethylene glycol (polyol component II, mass content 3.56 parts) were added to the reaction vessel. Then the temperature was gradually raised to 170±2℃ at 10℃ / hour and held. The acid value was tested every hour according to GB / T 6743 until the target acid value of 0-10 mg KOH / g was reached. After the acid value was qualified, the temperature was lowered to 105±2℃, butyl acetate (solvent, 15 parts by mass) was added, stirred evenly, and then cooled to below 70℃ and filtered out. Dendritic polyester was obtained.

[0117] The testing and characterization methods for the aliphatic amphiphilic dendritic polyesters prepared in Examples 1-10 and the dendritic polyesters prepared in Comparative Examples 1-3 are as follows:

[0118] (1) Appearance

[0119] The test was conducted in accordance with the national standard GB / T 8237.

[0120] (2) Solid content

[0121] The test was conducted in accordance with the national standard GB / T 1725. The test conditions were: temperature 140℃, baking time 60min, and sample size 1g.

[0122] (3) Hydroxyl value

[0123] Tested in accordance with international standard ISO 4629-3.

[0124] (4) Acid value

[0125] The test was conducted in accordance with the national standard GB / T 6743.

[0126] (5) Viscosity

[0127] The test was conducted in accordance with the national standard GB / T 10247. The test conditions were: viscosity test temperature of 30℃ and 80℃.

[0128] (6) Water solubility

[0129] The neutralization degree of Examples 1-10 and Comparative Examples 1-3 was calculated based on the polyester acid value. Dimethylethanolamine was added to achieve a neutralization degree of 70%, and then each mixture was mixed with deionized water at a mass ratio of 50:50. Water solubility qualification (OK) evaluation criteria: The solution is homogeneous and transparent.

[0130] Table 1 shows the test results of the above technical parameters for Examples 1-10 and Comparative Examples 1-3.

[0131] Table 1. Test results of technical parameters for Examples 1-10 and Comparative Examples 1-3

[0132] * "OK" means "qualified", "NG" means "unqualified", and "no data" is mainly because the resin is solid at 30°C.

[0133] As shown in Table 1, the aliphatic amphiphilic dendritic polyesters prepared by this invention all exhibit amphiphilicity and show significant advantages in terms of solid content and viscosity. Among them, Example 8 has the highest solid content, and Example 4 has the lowest viscosity.

[0134] Compared to Comparative Example 1, the aliphatic amphiphilic dendritic polyester prepared in Example 1 of this invention has a lower viscosity. This is mainly attributed to the better flexibility of aliphatic raw materials compared to aromatic raw materials, which can effectively reduce the viscosity of the polyester.

[0135] Compared to Comparative Example 2, the aliphatic amphiphilic dendritic polyester prepared in Example 2 of this invention exhibits lower viscosity. This is attributed to the ring-opening nucleation polymerization process using anhydrides and highly functional polyols employed in Example 2. This process reduces side reactions, forms a more compact polyester structure, and decreases the molecular radius, thereby effectively reducing viscosity.

[0136] Compared to Comparative Example 3, the aliphatic amphiphilic dendritic polyester prepared in Example 3 of this invention not only exhibits good hydrophilicity but also lower viscosity. This is mainly due to the precise control of the polyester's acid value to regulate the reaction process, reducing the formation of linear polyester byproducts and thus effectively lowering the polyester's viscosity. Furthermore, an appropriate acid value also endows the polyester with excellent hydrophilicity.

[0137] Through these optimization measures, the polyester product obtained by this invention is superior to the comparative product in terms of viscosity and solid content, demonstrating the significant technical advantages of this invention in the field of coating resins.

[0138] Evaluation of the application effect of aliphatic amphiphilic dendritic polyesters in automotive clear coats

[0139] To evaluate the application effect of the aliphatic amphiphilic dendritic polyester prepared in this invention in automotive clear coats, the following experiments were conducted:

[0140] Sources of materials and reagents:

[0141] KNT939 clear varnish base material was provided by Shanghai Jinlitai Chemical Co., Ltd.

[0142] The polyester resin WorléePol 1181 / 03 was supplied by Worlée GmbH, Germany.

[0143] The standard color paint swatches were provided by Shanghai Jinlitai Chemical Co., Ltd.

[0144] Test methods or standards:

[0145] (1) Surface drying time

[0146] The test was conducted in accordance with the national standard GB / T 13477.5.

[0147] (2) Adhesion

[0148] The test was conducted in accordance with the national standard GB / T 9286.

[0149] (3) Gloss

[0150] The test was conducted in accordance with the national standard GB / T 9754.

[0151] (4) Appearance and color of paint film

[0152] Tests were conducted in accordance with national standards GB / T9761 and GB / T11186.3.

[0153] (5) Gasoline resistance

[0154] The test was conducted in accordance with the national standard GB / T 9274. The test conditions were: soaking in RQ-93 gasoline for 24 hours. The paint film was qualified (OK). The evaluation criteria were: no bubbling, wrinkling and peeling; slight discoloration was allowed.

[0155] (6) Oil resistance

[0156] The test was conducted in accordance with the national standard GB / T 9274. The test conditions were: soaking in HQ-10 engine oil for 48 hours. The paint film was qualified (OK). The evaluation criteria were: no bubbling, wrinkling and peeling; slight discoloration was allowed.

[0157] (7) Alkali resistance

[0158] The test was conducted in accordance with the national standard GB / T 9274. The test conditions were: 23±2℃, soaking in 0.1mol / L sodium hydroxide (NaOH) for 24 hours. The evaluation criteria for the paint film qualification (OK) were: no softening, peeling, dissolution, or blistering.

[0159] (8) Acid resistance

[0160] The test was conducted in accordance with the national standard GB / T 9274. The test conditions were: 23±2℃, soaking in 0.05mol / L sulfuric acid (H2SO4) for 24 hours. The evaluation criteria for the paint film qualification (OK) were: no softening, peeling, dissolution, or blistering.

[0161] (9) Water resistance

[0162] The test was conducted in accordance with the national standard GB / T 5209. The test conditions were: 40±1℃, water immersion for 240 hours, and the paint film was qualified (OK). The evaluation criteria were: no bubbling, wrinkling and peeling; slight discoloration was allowed, and the adhesion was grade 0-1.

[0163] The dendritic polyester and polyester resin WorléePol1181 / 03 of Examples 1-3 and Comparative Examples 1-3 were mixed with KNT939 clear varnish base material at a mass ratio of 3:97, and stirred evenly using a disperser to prepare a coating composition. The same spraying process was controlled, and the coating composition was sprayed onto a standard color paint board (with KNT939 clear varnish base material sprayed onto the standard color paint board as a blank control). The samples were baked at 80°C for 30 minutes to obtain a paint film sample. The test results of the relevant performance indicators of the paint film are shown in Table 2.

[0164] Table 2. Coating film test results

[0165] Table 2 shows that the aliphatic amphiphilic dendritic polyester prepared in this invention exhibits significant comprehensive performance advantages in automotive clear coat applications. Specifically, this polyester has a fast drying speed, a high-quality film appearance, and excellent resistance to chemical media such as gasoline, engine oil, acids, alkalis, and water. These superior properties enable the polyester of this invention to simultaneously meet the requirements of rapid application and long-lasting protection in automotive clear coat applications, demonstrating outstanding application value.

[0166] Under the guidance of the present invention and the above embodiments, those skilled in the art will readily foresee that all the raw materials or their equivalents, processing methods or their equivalents listed or exemplified in the present invention can achieve the present invention, and that the upper and lower limits and range values ​​of the parameters of each raw material and processing method can also achieve the present invention. Examples are not listed one by one here.

Claims

1. An aliphatic amphiphilic dendritic polyester, characterized in that, The polyester comprises 60-100 parts by weight of polyester polyol and 0-40 parts by weight of solvent, wherein the polyester polyol comprises the following segments: The first segment is provided by polyol component I with high functionality; The second segment is provided by anhydride compounds; The third segment is provided by polyol component II with a molecular weight <500; in, The OH value of the polyester polyol is ≥115 KOH mg / g; The acid value of the polyester polyol is greater than or equal to 50 KOH mg / g and less than or equal to 290 KOH mg / g; The molar ratio of the acid anhydride compound to the high-functionality polyol component I is 3-6, wherein the average functionality of the high-functionality polyol component I is greater than or equal to 3.

2. The aliphatic amphiphilic dendritic polyester according to claim 1, characterized in that, The functionality of the polyol component II is greater than or equal to 2.

3. The aliphatic amphiphilic dendritic polyester according to claim 1, characterized in that, In the polyester polyol, the content of the high-functionality polyol component I is 6-22 parts, the content of the acid anhydride compound is 28-67 parts, and the content of the polyol component II with a molecular weight <500 is 13-53 parts.

4. The aliphatic amphiphilic dendritic polyester according to claim 1, characterized in that, The high-functionality polyol component I is selected from at least one of sorbitol, pentaerythritol, xylitol, maltitol, inositol, mannitol, glucose, trimethylolpropane, trimethylolethane, glycerol, arabinitol, trimethylolaminomethane, triethanolamine, and β-hydroxyalkylamide. The anhydride compound is selected from at least one of hexahydrophthalic anhydride, acetic anhydride, succinic anhydride, maleic anhydride, isohydrin, trichloroacetic anhydride, trifluoroacetic anhydride, adipic anhydride, tetrahydrophthalic anhydride, and maleic anhydride. The polyol component II with a molecular weight <500 is selected from sorbitol, pentaerythritol, xylitol, maltitol, inositol, mannitol, glucose, trimethylolpropane, trimethylolethane, glycerol, arabinitol, trimethylolaminomethane, triethanolamine, ethylene glycol, propylene glycol, butanediol, dimethyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-hydroxy-2,2-dimethyl-3-hydroxy-2,2- At least one of the following: dimethylpropyl propionate, 1,4-cyclohexanediol, trimethylpentanediol, HAA-β-hydroxyalkylamide, isosorbide, 1,2,6-hexanetriol, and hydrogenated bisphenol A.

5. The aliphatic amphiphilic dendritic polyester according to claim 1, characterized in that, The solvent is selected from at least one of butyl acetate, xylene, dipropylene glycol methyl ether, propylene glycol methyl ether acetate, propylene glycol methyl ether, 1,3,5-trimethylbenzene, and 1,2,4-trimethylbenzene.

6. A method for preparing the aliphatic amphiphilic dendritic polyester according to any one of claims 1-5, characterized in that, The method includes the following steps: 1) Add the high-functionality polyol component I to the reaction apparatus, slowly heat to 100-130℃, and stir for 0.5-2 hours; 2) Add the acid anhydride compound dropwise to the reaction solution prepared in step 1), and slowly heat to 120-160°C to react. Test the acid value at predetermined time intervals until the theoretical acid value is reached. 3) Add the polyol component II with a molecular weight <500 to the reaction solution prepared in step 2). After the addition is complete, heat the solution to 150-200°C at a rate of 8-12°C / hour and keep it at that temperature. Test the acid value at predetermined intervals until the target acid value is reached. 4) Cool the reaction solution prepared in step 3) to 100-120℃ and dehydrate it under vacuum pressure of -0.05 to -0.1 MPa for 0.5-2 hours; 5) Cool the reaction solution prepared in step 4) to 80-110°C, add 0-40 parts by weight of the solvent, stir evenly, cool to below 70-90°C, and filter out the material.

7. The method for preparing aliphatic amphiphilic dendritic polyester according to claim 6, characterized in that, In step 3) above, after the polyol component II is added, the temperature is raised to 150-200°C at a rate of 10°C / hour and held at that temperature; in steps 2) and 3) above, the predetermined time interval for testing the acid value is 1 hour.

8. The method for preparing aliphatic amphiphilic dendritic polyester according to claim 7, characterized in that, The theoretical acid value is calculated as follows: ((amount of acid anhydride compound * functionality - high-functionality polyol component I * functionality)) * 56100 / (mass of acid anhydride compound + mass of high-functionality polyol component I); the target acid value is greater than or equal to 50 KOH mg / g and less than or equal to 290 KOH mg / g.

9. A type of automotive clear coat, characterized in that, Includes the aliphatic amphiphilic dendritic polyester as described in any one of claims 1-5.

Images