A light-transmitting coating for an automobile exterior trim, a preparation method and a use method

Abstract

The present application relates to the field of paint, in particular to a kind of light-transmitting paint for automobile exterior trim, preparation method and use method, for solving the problem that the light transmittance of the light-transmitting paint for automobile exterior trim is not high enough, and the wear resistance and chemical resistance are poor;The light-transmitting paint for automobile exterior trim uses particle modified emulsion as main raw material, and by optimizing the formula, the paint has excellent light-transmitting performance, can provide clear and bright visual effect for automobile exterior trim, and improve the hardness and wear resistance of coating, so that automobile exterior trim is not easy to appear scratch in daily use, prolong the service life, and can effectively resist the erosion of environmental factors such as acid, alkali and moisture, prevent the coating from fading, powdering and other phenomena, ensure that the coating will not fall off in various harsh environments, ensure the color and gloss stability of automobile exterior trim in long-term use, and ensure the durability of decoration effect.

Description

Technical Field

[0001] This invention relates to the field of coatings, specifically to a translucent coating for automotive exterior trim parts, its preparation method, and its application method. Background Technology

[0002] With the development of the automotive industry, consumers have increasingly higher demands for the personalization and aesthetics of car exteriors. As an important component of a car's appearance, exterior trim directly impacts the overall image of the vehicle. Translucent coatings possess excellent optical properties, effectively transmitting light without compromising the vehicle's aesthetics, giving exterior trim a unique visual effect, creating a crystal-clear, light-and-shadow aesthetic, and enhancing the car's technological and fashionable appeal.

[0003] However, existing translucent coatings have some problems when applied to automotive exterior trim parts. For example, some coatings have insufficient light transmittance, resulting in poor visual appeal of the trim parts; their abrasion resistance and chemical resistance are also poor, making them prone to scratches, fading, cracking, and peeling during long-term use, affecting the service life and aesthetics of automotive exterior trim parts. Therefore, developing a translucent coating for automotive exterior trim parts with high light transmittance, good abrasion resistance, and chemical resistance is of significant practical importance. Summary of the Invention

[0004] In order to overcome the above-mentioned technical problems, the purpose of this invention is to provide a translucent coating for automotive exterior trim parts, a preparation method and a method of use, which solves the problems of insufficient light transmittance and poor wear resistance and chemical resistance of existing translucent coatings for automotive exterior trim parts.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A translucent coating for automotive exterior trim components comprises the following components in parts by weight:

[0007] The mixture contains 70-80 parts of particle-modified emulsion, 1-3 parts of antioxidant, 1-3 parts of ultraviolet absorber, 0.6-1.2 parts of light stabilizer, and 0.2-0.6 parts of leveling agent.

[0008] The particle-modified emulsion is prepared by the following steps:

[0009] Step a1: Add nano-silica and ethanol solution to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Purge with nitrogen for protection and stir for 20-30 min at 25-30℃ and 300-400 r / min. Then add (3-chloropropyl)triethoxysilane and continue stirring under reflux for 30-40 h. After the reaction is complete, cool the reaction product to room temperature and then filter under vacuum. Wash the filter cake 3-5 times with anhydrous ethanol and then place it in a vacuum drying oven and dry at 80-85℃ for 3-5 h to obtain silane-modified silica.

[0010] Step a2: Add silane-modified silica, 1,3,5-triaminobenzene, triethylamine, and chloroform to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and reflux condenser. Purge with nitrogen for protection and stir at 25-30℃ and a stirring rate of 300-400 r / min for 1-1.5 h. Then, heat to reflux and continue stirring for 10-15 h. After the reaction is complete, cool the reaction product to room temperature and then filter under vacuum. Wash the filter cake 3-5 times with sulfuric acid solution and anhydrous ethanol in sequence. Then place it in a vacuum drying oven and dry at 60-65℃ for 6-8 h to obtain polyamino-modified silica.

[0011] Step a3: Add 2,2-dimethylolpropionic acid, perfluoro-1-octanol, p-toluenesulfonic acid, and anhydrous acetone to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection and stir the reaction at 5-10℃ and 300-400 r / min for 15-20 min. Then raise the temperature to 120-130℃ and continue stirring for 6-7 h. After the reaction is complete, cool the reaction product to room temperature and wash it 2-3 times with sodium bicarbonate solution and distilled water in sequence. Then dry it with anhydrous magnesium sulfate and filter it under vacuum. Remove the solvent by rotary evaporation of the filtrate to obtain a fluorinated diol.

[0012] Step a4: Add polyether diol, toluene-2,4-diisocyanate, dibutyltin dilaurate, and anhydrous acetone to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection. Stir and react for 15-20 min at 25-30℃ and a stirring rate of 300-400 r / min. Then raise the temperature to 65-70℃ and continue stirring and reacting for 1-2 h. Then raise the temperature to 90-95℃ and continue stirring and reacting for 2-3 h. Then add fluorinated diol and continue stirring and reacting for 2-3 h. Then lower the temperature to 50-55℃ and add triethylamine to adjust the pH to 6-6.5. Then continue stirring and reacting for 30-40 min. Then add deionized water and continue stirring and reacting for 20-30 min. Adjust the solid content to 30-40% to obtain a fluorinated modified emulsion.

[0013] Step a5: Add the polyamine-modified silica and the fluorine-modified emulsion to a three-necked flask equipped with a stirrer and a thermometer. Stir the reaction at 25-30℃ and a stirring rate of 300-400 r / min for 15-20 min. Then, raise the temperature to 40-45℃ and continue stirring for 15-20 h. After the reaction is completed, cool the reaction product to room temperature to obtain the particle-modified emulsion.

[0014] As a further aspect of the present invention: the ratio of the amount of nano-silica, ethanol solution and (3-chloropropyl)triethoxysilane used in step a1 is 1g:50-60mL:0.8-2.2g.

[0015] As a further aspect of the present invention: the volume fraction of the ethanol solution in step a1 is 85%.

[0016] As a further embodiment of the present invention: the ratio of the amount of silane-modified silica, 1,3,5-triaminobenzene, triethylamine and chloroform used in step a2 is 1g:1.1-2.1g:1.2-1.6mL:60-70mL.

[0017] As a further aspect of the present invention: the molar concentration of the sulfuric acid solution in step a2 is 0.1-0.2 mol / L.

[0018] As a further aspect of the present invention: the ratio of 2,2-dihydroxymethylpropionic acid, perfluoro-1-octanol, p-toluenesulfonic acid and anhydrous acetone in step a3 is 10 mmol: 10 mmol: 0.2-0.3 g: 50-60 mL.

[0019] As a further aspect of the present invention: the mass fraction of the sodium bicarbonate solution in step a3 is 8-10%.

[0020] As a further aspect of the present invention: the ratio of the amount of polyether diol, toluene-2,4-diisocyanate, dibutyltin dilaurate, anhydrous acetone and fluorinated diol in step a4 is 40-50g: 20g: 0.8-1.2g: 30-50mL: 5-13g.

[0021] As a further aspect of the present invention: the polyether diol in step a4 is one of polypropylene glycol PPG-1000, polypropylene glycol PPG-600, and polyethylene glycol PEG-600.

[0022] As a further aspect of the present invention: the ratio of the amount of polyamino-modified silica and the fluorinated modified emulsion used in step a5 is 3-15g:100g.

[0023] As a further aspect of the present invention: a method for preparing a translucent coating for automotive exterior trim parts, comprising the following steps:

[0024] Step 1: Weigh out 70-80 parts of particle-modified emulsion, 1-3 parts of antioxidant, 1-3 parts of ultraviolet absorber, 0.6-1.2 parts of light stabilizer, and 0.2-0.6 parts of leveling agent according to the weight ratio, and set aside.

[0025] Step 2: Add the particle-modified emulsion, antioxidant, ultraviolet absorber, light stabilizer and leveling agent to the reaction vessel, and stir and react for 45-75 minutes at a temperature of 25-30℃ and a stirring rate of 600-800 r / min. Then filter with a 200-300 mesh filter to obtain a translucent coating for automotive exterior trim parts.

[0026] As a further aspect of the present invention: the antioxidant is one of antioxidant 300, antioxidant 1076 and antioxidant 1135.

[0027] As a further aspect of the present invention: the light stabilizer is light stabilizer 770.

[0028] As a further aspect of the present invention: the leveling agent is one of the following: leveling agent BYK306, leveling agent BYK331, and leveling agent BYK358.

[0029] As a further aspect of the present invention: a method for using a translucent coating for automotive exterior trim parts, comprising the following steps:

[0030] Apply translucent paint to the exterior trim of the car, then place it in a forced-air drying oven to bake and cure it into a coating.

[0031] The beneficial effects of this invention are:

[0032] This invention discloses a translucent coating for automotive exterior trim parts, its preparation method, and its application method. The coating involves adding a particle-modified emulsion, antioxidant, ultraviolet absorber, light stabilizer, and leveling agent to a reaction vessel, stirring and reacting, followed by filtration to obtain the translucent coating for automotive exterior trim parts. This translucent coating uses a particle-modified emulsion as the main raw material, and through optimized formulation, it possesses excellent light transmission properties, providing a clear and bright visual effect for automotive exterior trim parts. It also improves the hardness and wear resistance of the coating, making the automotive exterior trim parts less prone to scratches during daily use, extending their service life, and effectively resisting the erosion of environmental factors such as acids, alkalis, and moisture. It prevents fading and chalking of the coating, ensuring that the coating will not peel off under various harsh environments, guaranteeing the stability of the color and gloss of the automotive exterior trim parts during long-term use, and ensuring the durability of the decorative effect.

[0033] In the preparation of translucent coatings for automotive exterior trim parts, a particle-modified emulsion was first prepared. Nano-silica was treated with (3-chloropropyl)triethoxysilane. The siloxane on (3-chloropropyl)triethoxysilane hydrolyzed to form silanols, which were then grafted onto the surface of the nano-silica particles, simultaneously introducing chlorine atoms to obtain silane-modified silica. Then, silane-modified silica was treated with 1,3,5-triaminobenzene. The amino groups on 1,3,5-triaminobenzene reacted with the chlorine atoms on the silane-modified silica, simultaneously introducing a large number of amino groups to obtain polyamino-modified silica. Subsequently, 2,2-dimethylolpropionic acid and perfluoro-1-octanol were reacted. The carboxyl groups on 2,2-dimethylolpropionic acid reacted with the hydroxyl groups on perfluoro-1-octanol to form a diol containing a large amount of fluorine, yielding a fluorinated diol. This was then polymerized using polyether diol and toluene-2,4-diisocyanate as monomers, and the fluorinated diol was used as the polymer. The alcohol undergoes chain extension and further polymerization to form a polyurethane polymer, resulting in a fluorinated modified emulsion. Finally, a reaction is performed between polyamine-modified silica and the fluorinated modified emulsion. The amino groups on the polyamine-modified silica react with the isocyanate groups on the polymer in the fluorinated modified emulsion, forming chemical bonds between them, thus obtaining the fluorinated modified emulsion. The polymer in this fluorinated modified emulsion contains a large amount of fluorine, giving the coating excellent water resistance and acid / alkali resistance, while also imparting lubricity and improving its wear resistance. The addition of silica enhances the mechanical properties of the coating, further improving its wear and scratch resistance. After modification, it can be uniformly dispersed in the coating, resulting in less scattering of incident light and ensuring the coating's light transmittance. Furthermore, the addition of polyamine-modified silica significantly increases the degree of cross-linking between polymers, thereby improving the coating's density and overall performance, while also significantly enhancing the coating's long-term stability. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1:

[0036] This embodiment describes a method for preparing a translucent coating for automotive exterior trim parts, comprising the following steps:

[0037] Step S1: Add 1g of nano-silica and 50mL of 85% ethanol solution to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Purge with nitrogen for protection and stir at 25℃ and 300r / min for 20min. Then add 0.8g of (3-chloropropyl)triethoxysilane and continue stirring at reflux for 30h. After the reaction is complete, cool the reaction product to room temperature and then filter under vacuum. Wash the filter cake three times with anhydrous ethanol and then place it in a vacuum drying oven and dry at 80℃ for 3h to obtain silane-modified silica.

[0038] Step S2: 1g of silane-modified silica, 1.1g of 1,3,5-triaminobenzene, 1.2mL of triethylamine and 60mL of chloroform were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection, and the mixture was stirred at 25℃ and a stirring rate of 300r / min for 1h. Then the temperature was raised to reflux and the mixture was stirred for another 10h. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filter cake was washed three times with sulfuric acid solution with a molar concentration of 0.1mol / L and anhydrous ethanol, and then placed in a vacuum drying oven and dried at 60℃ for 6h to obtain polyamino-modified silica.

[0039] Step S3: 10 mmol of 2,2-dihydroxymethylpropionic acid, 10 mmol of perfluoro-1-octanol, 0.2 g of p-toluenesulfonic acid, and 50 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection, and the mixture was stirred at 5 °C and a stirring rate of 300 r / min for 15 min. Then, the temperature was raised to 120 °C and the mixture was stirred for 6 h. After the reaction was completed, the reaction product was cooled to room temperature and then washed twice with 8% sodium bicarbonate solution and distilled water, respectively. The product was then dried with anhydrous magnesium sulfate and vacuum filtered. The solvent was removed by rotary evaporation of the filtrate to obtain a fluorinated diol.

[0040] Step S4: Add 40g of polyether diol, 20g of toluene-2,4-diisocyanate, 0.8g of dibutyltin dilaurate, and 30mL of anhydrous acetone to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection. Stir and react at 25°C and a stirring rate of 300r / min for 15min. Then raise the temperature to 65°C and continue stirring for 1h. Next, raise the temperature to 90°C and continue stirring for 2h. Then add 5g of fluorinated diol and continue stirring for 2h. Then lower the temperature to 50°C and add triethylamine to adjust the pH to 6. Continue stirring and react for 30min. Then add deionized water and continue stirring for 20min, adjusting the solid content to 30% to obtain a fluorinated modified emulsion. The polyether diol is polypropylene glycol PPG-1000.

[0041] Step S5: Add 3g of polyamino-modified silica and 100g of fluorine-modified emulsion to a three-necked flask equipped with a stirrer and a thermometer. Stir and react for 15 minutes at 25°C and a stirring rate of 300r / min. Then, raise the temperature to 40°C and continue stirring and reacting for 15 hours. After the reaction is completed, cool the reaction product to room temperature to obtain the particle-modified emulsion.

[0042] Step S6: Weigh out 70 parts by weight of particle-modified emulsion, 1 part of antioxidant, 1 part of ultraviolet absorber, 0.6 parts of light stabilizer, and 0.2 parts of leveling agent, and set aside; the antioxidant is antioxidant 300; the light stabilizer is light stabilizer 770; and the leveling agent is leveling agent BYK306.

[0043] Step S7: Add the particle-modified emulsion, antioxidant, ultraviolet absorber, light stabilizer and leveling agent to the reaction vessel, stir and react for 45 min at a temperature of 25℃ and a stirring rate of 600 r / min, and then filter with a 200 mesh filter to obtain a translucent coating for automotive exterior trim parts.

[0044] Example 2:

[0045] This embodiment describes a method for preparing a translucent coating for automotive exterior trim parts, comprising the following steps:

[0046] Step S1: Add 1g of nano-silica and 55mL of 85% ethanol solution to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Purge with nitrogen and stir for 25min at 28℃ and 350r / min. Then add 1.5g of (3-chloropropyl)triethoxysilane and continue stirring under reflux for 35h. After the reaction is complete, cool the reaction product to room temperature and then filter under vacuum. Wash the filter cake four times with anhydrous ethanol and then place it in a vacuum drying oven and dry at 82℃ for 4h to obtain silane-modified silica.

[0047] Step S2: 1g of silane-modified silica, 1.6g of 1,3,5-triaminobenzene, 1.4mL of triethylamine and 65mL of chloroform were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection, and the mixture was stirred at 28℃ and a stirring rate of 350r / min for 1.2h. Then the temperature was raised to reflux and the mixture was stirred for another 12h. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filter cake was washed four times with sulfuric acid solution with a molar concentration of 0.15mol / L and anhydrous ethanol. Then it was placed in a vacuum drying oven and dried at 62℃ for 7h to obtain polyamino-modified silica.

[0048] Step S3: 10 mmol of 2,2-dimethylolpropionic acid, 10 mmol of perfluoro-1-octanol, 0.25 g of p-toluenesulfonic acid, and 55 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection, and the mixture was stirred at 7 °C and a stirring rate of 350 r / min for 18 min. Then, the temperature was raised to 125 °C and the mixture was stirred for another 6.5 h. After the reaction was completed, the reaction product was cooled to room temperature and then washed twice with 9% sodium bicarbonate solution and distilled water, respectively. The product was then dried with anhydrous magnesium sulfate and vacuum filtered. The solvent was removed by rotary evaporation of the filtrate to obtain a fluorinated diol.

[0049] Step S4: Add 45g of polyether diol, 20g of toluene-2,4-diisocyanate, 1.0g of dibutyltin dilaurate, and 40mL of anhydrous acetone to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection. Stir and react at 28℃ and a stirring rate of 350r / min for 18min. Then raise the temperature to 68℃ and continue stirring for 1.5h. Next, raise the temperature to 92℃ and continue stirring for 2.5h. Then add 9g of fluorinated diol and continue stirring for 2.5h. Then lower the temperature to 52℃ and add triethylamine to adjust the pH to 6. Continue stirring for 35min. Then add deionized water and continue stirring for 25min, adjusting the solid content to 35% to obtain a fluorinated modified emulsion; the polypropylene glycol PPG-600.

[0050] Step S5: Add 9g of polyamino-modified silica and 100g of fluorine-modified emulsion to a three-necked flask equipped with a stirrer and a thermometer. Stir and react for 18 minutes at a temperature of 28℃ and a stirring rate of 350r / min. Then, raise the temperature to 42℃ and continue stirring and reacting for 18 hours. After the reaction is completed, cool the reaction product to room temperature to obtain the particle-modified emulsion.

[0051] Step S6: Weigh out 75 parts by weight of particle-modified emulsion, 2 parts by weight of antioxidant, 2 parts by weight of UV absorber, 0.9 parts by weight of light stabilizer and 0.4 parts by weight of leveling agent, and set aside; the antioxidant is antioxidant 1076; the light stabilizer is light stabilizer 770; the leveling agent is leveling agent BYK331;

[0052] Step S7: Add the particle-modified emulsion, antioxidant, ultraviolet absorber, light stabilizer and leveling agent to the reaction vessel, stir and react for 60 min at a temperature of 28℃ and a stirring rate of 700 r / min, and then filter with a 250 mesh filter to obtain a translucent coating for automotive exterior trim parts.

[0053] Example 3:

[0054] This embodiment describes a method for preparing a translucent coating for automotive exterior trim parts, comprising the following steps:

[0055] Step S1: Add 1g of nano-silica and 60mL of 85% ethanol solution to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Purge with nitrogen for protection and stir at 30℃ and 400r / min for 30min. Then add 2.2g of (3-chloropropyl)triethoxysilane and continue stirring at reflux for 40h. After the reaction is complete, cool the reaction product to room temperature and then filter under vacuum. Wash the filter cake 5 times with anhydrous ethanol and then place it in a vacuum drying oven and dry at 85℃ for 5h to obtain silane-modified silica.

[0056] Step S2: 1g of silane-modified silica, 2.1g of 1,3,5-triaminobenzene, 1.6mL of triethylamine and 70mL of chloroform were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection, and the mixture was stirred at 30℃ and 400r / min for 1.5h. Then the temperature was raised to reflux and the mixture was stirred for another 15h. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filter cake was washed five times with sulfuric acid solution with a molar concentration of 0.2mol / L and anhydrous ethanol. Then it was placed in a vacuum drying oven and dried at 65℃ for 8h to obtain polyamino-modified silica.

[0057] Step S3: 10 mmol of 2,2-dihydroxymethylpropionic acid, 10 mmol of perfluoro-1-octanol, 0.3 g of p-toluenesulfonic acid, and 60 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection, and the mixture was stirred at 10 °C and 400 r / min for 20 min. Then, the temperature was raised to 130 °C and the mixture was stirred for 7 h. After the reaction was completed, the reaction product was cooled to room temperature and then washed three times with 10% sodium bicarbonate solution and distilled water. The product was then dried with anhydrous magnesium sulfate and vacuum filtered. The solvent was removed by rotary evaporation of the filtrate to obtain a fluorinated diol.

[0058] Step S4: Add 50g of polyether diol, 20g of toluene-2,4-diisocyanate, 1.2g of dibutyltin dilaurate, and 50mL of anhydrous acetone to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection. Stir and react at 30℃ and a stirring rate of 400r / min for 20min. Then raise the temperature to 70℃ and continue stirring for 2h. Next, raise the temperature to 95℃ and continue stirring for 3h. Then add 13g of fluorinated diol and continue stirring for 3h. Next, lower the temperature to 55℃ and add triethylamine to adjust the pH to 6.5. Continue stirring for 40min, then add deionized water and continue stirring for 30min, adjusting the solid content to 40% to obtain a fluorinated modified emulsion. The polyether diol is polyethylene glycol PEG-600.

[0059] Step S5: Add 15g of polyamino-modified silica and 100g of fluorine-modified emulsion to a three-necked flask equipped with a stirrer and a thermometer. Stir and react for 20 minutes at 30°C and a stirring rate of 400r / min. Then, raise the temperature to 45°C and continue stirring and reacting for 20 hours. After the reaction is completed, cool the reaction product to room temperature to obtain the particle-modified emulsion.

[0060] Step S6: Weigh out 80 parts by weight of particle-modified emulsion, 3 parts by weight of antioxidant, 3 parts by weight of UV absorber, 1.2 parts by weight of light stabilizer and 0.6 parts by weight of leveling agent, and set aside; the antioxidant is antioxidant 1135; the light stabilizer is light stabilizer 770; the leveling agent is leveling agent BYK358;

[0061] Step S7: Add the particle-modified emulsion, antioxidant, ultraviolet absorber, light stabilizer and leveling agent to the reaction vessel, stir and react for 75 minutes at a temperature of 30℃ and a stirring rate of 800r / min, and then filter with a 300-mesh filter to obtain a translucent coating for automotive exterior trim parts.

[0062] Comparative Example 1:

[0063] This comparative example illustrates a method for preparing a translucent coating for automotive exterior trim parts, comprising the following steps:

[0064] Step S1: Add 50g of polyether diol, 20g of toluene-2,4-diisocyanate, 1.2g of dibutyltin dilaurate, and 50mL of anhydrous acetone to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection. Stir and react at 30℃ and a stirring rate of 400r / min for 20min. Then raise the temperature to 70℃ and continue stirring for 2h. Next, raise the temperature to 95℃ and continue stirring for 3h. Then lower the temperature to 55℃ and add triethylamine to adjust the pH to 6.5. Continue stirring and react for 40min. Finally, add deionized water and continue stirring for 30min, adjusting the solid content to 40% to obtain a modified emulsion. The polyether diol is polyethylene glycol PEG-600.

[0065] Step S2: Weigh out 80 parts of modified emulsion, 3 parts of antioxidant, 3 parts of ultraviolet absorber, 1.2 parts of light stabilizer, and 0.6 parts of leveling agent according to the following weight proportions, and set aside for later use; the antioxidant is antioxidant 1135; the light stabilizer is light stabilizer 770; and the leveling agent is leveling agent BYK358.

[0066] Step S3: Add the modified emulsion, antioxidant, ultraviolet absorber, light stabilizer and leveling agent to the reaction vessel, stir and react for 75 minutes at a temperature of 30℃ and a stirring rate of 800r / min, and then filter with a 300-mesh filter to obtain a translucent coating for automotive exterior trim parts.

[0067] Comparative Example 2:

[0068] This comparative example illustrates a method for preparing a translucent coating for automotive exterior trim parts, comprising the following steps:

[0069] Step S1: 10 mmol of 2,2-dimethylolpropionic acid, 10 mmol of perfluoro-1-octanol, 0.3 g of p-toluenesulfonic acid, and 60 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection, and the mixture was stirred at 10 °C and a stirring rate of 400 r / min for 20 min. Then, the temperature was raised to 130 °C and the mixture was stirred for 7 h. After the reaction was completed, the reaction product was cooled to room temperature and then washed three times with 10% sodium bicarbonate solution and distilled water. The product was then dried with anhydrous magnesium sulfate and vacuum filtered. The solvent was removed by rotary evaporation of the filtrate to obtain a fluorinated diol.

[0070] Step S2: Add 50g of polyether diol, 20g of toluene-2,4-diisocyanate, 1.2g of dibutyltin dilaurate, and 50mL of anhydrous acetone to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection. Stir and react at 30℃ and a stirring rate of 400r / min for 20min. Then raise the temperature to 70℃ and continue stirring for 2h. Next, raise the temperature to 95℃ and continue stirring for 3h. Then add 13g of fluorinated diol and continue stirring for 3h. Then lower the temperature to 55℃ and add triethylamine to adjust the pH to 6.5. Continue stirring for 40min, then add deionized water and continue stirring for 30min, adjusting the solid content to 40% to obtain a fluorinated modified emulsion. The polyether diol is polyethylene glycol PEG-600.

[0071] Step S3: Weigh out 80 parts by weight of fluorinated modified emulsion, 3 parts by weight of antioxidant, 3 parts by weight of UV absorber, 1.2 parts by weight of light stabilizer and 0.6 parts by weight of leveling agent, and set aside; the antioxidant is antioxidant 1135; the light stabilizer is light stabilizer 770; the leveling agent is leveling agent BYK358;

[0072] Step S4: Add the fluorinated modified emulsion, antioxidant, ultraviolet absorber, light stabilizer and leveling agent to the reaction vessel, stir and react for 75 minutes at a temperature of 30℃ and a stirring rate of 800 r / min, and then filter with a 300 mesh filter to obtain a translucent coating for automotive exterior trim parts.

[0073] Comparative Example 3:

[0074] This comparative example illustrates a method for preparing a translucent coating for automotive exterior trim parts, comprising the following steps:

[0075] Step S1: 10 mmol of 2,2-dimethylolpropionic acid, 10 mmol of perfluoro-1-octanol, 0.3 g of p-toluenesulfonic acid, and 60 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection, and the mixture was stirred at 10 °C and a stirring rate of 400 r / min for 20 min. Then, the temperature was raised to 130 °C and the mixture was stirred for 7 h. After the reaction was completed, the reaction product was cooled to room temperature and then washed three times with 10% sodium bicarbonate solution and distilled water. The product was then dried with anhydrous magnesium sulfate and vacuum filtered. The solvent was removed by rotary evaporation of the filtrate to obtain a fluorinated diol.

[0076] Step S2: Add 50g of polyether diol, 20g of toluene-2,4-diisocyanate, 1.2g of dibutyltin dilaurate, and 50mL of anhydrous acetone to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection. Stir and react at 30℃ and a stirring rate of 400r / min for 20min. Then raise the temperature to 70℃ and continue stirring for 2h. Next, raise the temperature to 95℃ and continue stirring for 3h. Then add 13g of fluorinated diol and continue stirring for 3h. Then lower the temperature to 55℃ and add triethylamine to adjust the pH to 6.5. Continue stirring for 40min, then add deionized water and continue stirring for 30min, adjusting the solid content to 40% to obtain a fluorinated modified emulsion. The polyether diol is polyethylene glycol PEG-600.

[0077] Step S3: Add 15g of nano-silica and 100g of fluorine-modified emulsion to a three-necked flask equipped with a stirrer and a thermometer. Stir and react for 20min at 30℃ and 400r / min. Then, raise the temperature to 45℃ and continue stirring for 20h. After the reaction is completed, cool the reaction product to room temperature to obtain the particle-modified emulsion.

[0078] Step S4: Weigh out 80 parts by weight of particle-modified emulsion, 3 parts by weight of antioxidant, 3 parts by weight of UV absorber, 1.2 parts by weight of light stabilizer and 0.6 parts by weight of leveling agent, and set aside; the antioxidant is antioxidant 1135; the light stabilizer is light stabilizer 770; the leveling agent is leveling agent BYK358;

[0079] Step S5: Add the particle-modified emulsion, antioxidant, ultraviolet absorber, light stabilizer and leveling agent to the reaction vessel, stir and react for 75 minutes at a temperature of 30℃ and a stirring rate of 800r / min, and then filter with a 300-mesh filter to obtain a translucent coating for automotive exterior trim parts.

[0080] Comparative Example 4:

[0081] This comparative example illustrates a method for preparing a translucent coating for automotive exterior trim parts, comprising the following steps:

[0082] Step S1: Add 1g of nano-silica and 60mL of 85% ethanol solution to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Purge with nitrogen for protection and stir at 30℃ and 400r / min for 30min. Then add 2.2g of (3-chloropropyl)triethoxysilane and continue stirring at reflux for 40h. After the reaction is complete, cool the reaction product to room temperature and then filter under vacuum. Wash the filter cake 5 times with anhydrous ethanol and then place it in a vacuum drying oven and dry at 85℃ for 5h to obtain silane-modified silica.

[0083] Step S2: 10 mmol of 2,2-dimethylolpropionic acid, 10 mmol of perfluoro-1-octanol, 0.3 g of p-toluenesulfonic acid, and 60 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas was introduced for protection, and the mixture was stirred at 10 °C and a stirring rate of 400 r / min for 20 min. Then, the temperature was raised to 130 °C and the mixture was stirred for another 7 h. After the reaction was completed, the reaction product was cooled to room temperature and then washed three times with a 10% sodium bicarbonate solution and distilled water, respectively. The product was then dried with anhydrous magnesium sulfate and vacuum filtered. The solvent was removed by rotary evaporation of the filtrate to obtain a fluorinated diol.

[0084] Step S3: Add 50g of polyether diol, 20g of toluene-2,4-diisocyanate, 1.2g of dibutyltin dilaurate, and 50mL of anhydrous acetone to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection. Stir and react at 30℃ and a stirring rate of 400r / min for 20min. Then raise the temperature to 70℃ and continue stirring for 2h. Next, raise the temperature to 95℃ and continue stirring for 3h. Then add 13g of fluorinated diol and continue stirring for 3h. Then lower the temperature to 55℃ and add triethylamine to adjust the pH to 6.5. Continue stirring for 40min, then add deionized water and continue stirring for 30min, adjusting the solid content to 40% to obtain a fluorinated modified emulsion. The polyether diol is polyethylene glycol PEG-600.

[0085] Step S4: Add 15g of silane-modified silica and 100g of fluorine-modified emulsion to a three-necked flask equipped with a stirrer and a thermometer. Stir and react for 20 minutes at 30°C and a stirring rate of 400r / min. Then, raise the temperature to 45°C and continue stirring and reacting for 20 hours. After the reaction is completed, cool the reaction product to room temperature to obtain the particle-modified emulsion.

[0086] Step S5: Weigh out 80 parts by weight of particle-modified emulsion, 3 parts by weight of antioxidant, 3 parts by weight of UV absorber, 1.2 parts by weight of light stabilizer and 0.6 parts by weight of leveling agent, and set aside; the antioxidant is antioxidant 1135; the light stabilizer is light stabilizer 770; the leveling agent is leveling agent BYK358;

[0087] Step S6: Add the particle-modified emulsion, antioxidant, ultraviolet absorber, light stabilizer and leveling agent to the reaction vessel, stir and react for 75 minutes at a temperature of 30℃ and a stirring rate of 800 r / min, and then filter with a 300 mesh filter to obtain a translucent coating for automotive exterior trim parts.

[0088] The translucent coatings for automotive exterior trim parts of Examples 1-3 and Comparative Examples 1-4 were sprayed onto Q235 steel plates using a W-101 spray gun. The dry film thickness was controlled at 100 μm. The plates were then placed in a forced-air drying oven and baked at 80°C for 6 hours. After curing into a coating, the plates were removed and allowed to cool naturally for 24 hours before coating performance testing.

[0089] The test results are shown in the table below:

[0090]

[0091] Among them, light transmittance is the ultraviolet transmittance of the test coating at a wavelength of 600nm; acid resistance is determined by immersing the coating in a 5% sulfuric acid solution for 48 hours and observing the changes in the coating; alkali resistance is determined by immersing the coating in a 5% sodium hydroxide solution for 48 hours and observing the changes in the coating; and wear is determined by the mass loss after 500 cycles of friction under the conditions of a paint film abrasion tester with a rotation speed of 60r / min and a load of 1000g.

[0092] Referring to the data in the table above, and based on the comparison between Examples 1-3 and Comparative Examples 1-4, it can be seen that the translucent coating for automotive exterior trim parts of the present invention has good light transmittance, acid and alkali resistance, and wear resistance.

[0093] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0094] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in this application, they should all fall within the protection scope of the present invention.

Claims

1. A translucent coating for automotive exterior trim parts, characterized in that, Includes the following components by weight: The mixture contains 70-80 parts of particle-modified emulsion, 1-3 parts of antioxidant, 1-3 parts of ultraviolet absorber, 0.6-1.2 parts of light stabilizer, and 0.2-0.6 parts of leveling agent. The particle-modified emulsion is prepared by the following steps: Step a1: Nano silica and ethanol solution are stirred and reacted, then (3-chloropropyl)triethoxysilane is added and the reaction is continued. After the reaction is completed, the reaction product is cooled, then vacuum filtered, and the filter cake is washed and dried to obtain silane-modified silica. Step a2: Silane-modified silica, 1,3,5-triaminobenzene, triethylamine and chloroform were stirred and reacted. After the reaction was completed, the reaction product was cooled and then vacuum filtered. The filter cake was washed and dried to obtain polyamino-modified silica. Step a3: 2,2-Dihydroxymethylpropionic acid, perfluoro-1-octanol, p-toluenesulfonic acid and anhydrous acetone were stirred and reacted. After the reaction was completed, the reaction product was cooled, washed and dried, then vacuum filtered, and the filtrate was evaporated by rotary evaporation to obtain a fluorinated diol. Step a4: Polyether diol, toluene-2,4-diisocyanate, dibutyltin dilaurate and anhydrous acetone are stirred and reacted. Then, fluorinated diol is added and the reaction is continued with stirring. Triethylamine is then used to adjust the pH. Finally, deionized water is added and the reaction is continued with stirring to obtain a fluorinated modified emulsion. Step a5: The polyamine-modified silica and the fluorine-modified emulsion are stirred and reacted. After the reaction is completed, the reaction product is cooled to obtain the particle-modified emulsion.

2. The translucent coating for automotive exterior trim parts according to claim 1, characterized in that, In step a1, the ratio of nano-silica, ethanol solution, and (3-chloropropyl)triethoxysilane is 1g:50-60mL:0.8-2.2g; the volume fraction of the ethanol solution is 85%.

3. The translucent coating for automotive exterior trim parts according to claim 1, characterized in that, The ratio of silane-modified silica, 1,3,5-triaminobenzene, triethylamine, and chloroform in step a2 is 1g:1.1-2.1g:1.2-1.6mL:60-70mL.

4. The translucent coating for automotive exterior trim parts according to claim 1, characterized in that, The ratio of 2,2-dimethylolpropionic acid, perfluoro-1-octanol, p-toluenesulfonic acid, and anhydrous acetone in step a3 is 10 mmol: 10 mmol: 0.2-0.3 g: 50-60 mL.

5. The translucent coating for automotive exterior trim parts according to claim 1, characterized in that, In step a4, the ratio of the polyether diol, toluene-2,4-diisocyanate, dibutyltin dilaurate, anhydrous acetone, and fluorinated diol is 40-50g:20g:0.8-1.2g:30-50mL:5-13g; the polyether diol is one of polypropylene glycol PPG-1000, polypropylene glycol PPG-600, and polyethylene glycol PEG-600.

6. The translucent coating for automotive exterior trim parts according to claim 1, characterized in that, The ratio of the amount of polyamino-modified silica to the fluorinated modified emulsion in step a5 is 3-15g:100g.

7. A method for preparing a translucent coating for automotive exterior trim parts as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Weigh out 70-80 parts of particle-modified emulsion, 1-3 parts of antioxidant, 1-3 parts of ultraviolet absorber, 0.6-1.2 parts of light stabilizer, and 0.2-0.6 parts of leveling agent according to the weight ratio, and set aside. Step 2: Add the particle-modified emulsion, antioxidant, ultraviolet absorber, light stabilizer and leveling agent to the reaction vessel, and stir and react for 45-75 minutes at a temperature of 25-30℃ and a stirring rate of 600-800 r / min. Then filter with a 200-300 mesh filter to obtain a translucent coating for automotive exterior trim parts.

8. The method for preparing a translucent coating for automotive exterior trim parts according to claim 7, characterized in that, The antioxidant is one of antioxidant 300, antioxidant 1076, and antioxidant 1135; the light stabilizer is light stabilizer 770.

9. The method for preparing a translucent coating for automotive exterior trim parts according to claim 7, characterized in that, The leveling agent is one of the following: leveling agent BYK306, leveling agent BYK331, and leveling agent BYK358.

10. A method of using a translucent coating for automotive exterior trim prepared by the method described in any one of claims 7-9, characterized in that, Includes the following steps: Apply translucent paint to the exterior trim of the car, then place it in a forced-air drying oven to bake and cure it into a coating.

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