Light-transmitting coating for automobile outer decorating part, preparation method and use method

Abstract

The invention relates to the field of coatings, in particular to a light-transmitting coating for an automobile outer decorative part, a preparation method and a use method, and aims to solve the problems of low light transmittance and poorer wear resistance and chemical resistance of the conventional light-transmitting coating for the automobile outer decorative part. According to the light-transmitting coating for the automobile outer decorating part, the particle modified emulsion is used as a main raw material, and the formula is optimized, so that the coating has excellent light-transmitting performance, a clear and bright visual effect can be provided for the automobile outer decorating part, the hardness and wear resistance of the coating are improved, the automobile outer decorating part is not prone to being scratched in daily use, and the service life of the automobile outer decorating part is prolonged. According to the coating, the service life is prolonged, corrosion caused by environmental factors such as acid, alkali and moisture can be effectively resisted, the phenomena of color fading, pulverization and the like of the coating are prevented, the coating is prevented from falling off in various severe environments, the stability of color and gloss of the automobile outer decorating part in the long-term use process is guaranteed, and the durability of the decorating effect is guaranteed.

Description

Technical Field

[0001] The invention relates to the field of coatings, and in particular to a light-transmitting coating for automobile exterior decorative parts, a preparation method and a use method thereof. Background Art

[0002] With the development of the automobile industry, consumers have higher and higher requirements for the personalization and aesthetics of automobile appearance. As an important part of automobile appearance, the decorative effect of automobile exterior decoration directly affects the overall image of the car. Translucent paint has good optical properties and can effectively transmit light without affecting the beauty of the vehicle, giving automobile exterior decoration a unique visual effect, creating a crystal clear, light and shadow changing beauty, and increasing the car's sense of technology and fashion.

[0003] However, existing light-transmitting coatings have some problems when applied to automotive exterior decorations. For example, the light transmittance of some coatings is not high enough, resulting in poor visual effects of decorative parts; the wear resistance and chemical resistance of the coatings are poor, and they are prone to scratches, fading, cracking and falling off during long-term use, affecting the service life and aesthetics of automotive exterior decorations. Therefore, it is of great practical significance to develop a light-transmitting coating for automotive exterior decorations with high light transmittance, good wear resistance and chemical resistance. Summary of the invention

[0004] In order to overcome the above-mentioned technical problems, the purpose of the present invention is to provide a light-transmitting coating for automobile exterior decoration parts, a preparation method and a use method, which solves the problem that the light transmittance of existing light-transmitting coatings for automobile exterior decoration parts is not high enough and the wear resistance and chemical resistance are poor.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A light-transmitting coating for automobile exterior decoration parts comprises the following components in parts by weight:

[0007] 70-80 parts of particle modified latex, 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] Wherein, the particle-modified latex is prepared by the following steps:

[0009] Step a1: Add nano-silica and ethanol solution to a three-necked flask equipped with a stirrer, a thermometer, an air duct and a reflux condenser, introduce nitrogen protection, stir and react for 20-30 minutes at a temperature of 25-30° C. and a stirring rate of 300-400 r / min, then add (3-chloropropyl)triethoxysilane and continue stirring and reacting for 30-40 hours under the condition of heating to reflux, and after the reaction is completed, cool the reaction product to room temperature, and then vacuum filter, wash the filter cake with anhydrous ethanol for 3-5 times, and then place it in a vacuum drying oven, and dry it for 3-5 hours at a temperature of 80-85° C. to obtain silane-modified silica;

[0010] Step a2: adding silane-modified silica, 1,3,5-triaminobenzene, triethylamine and chloroform into a three-necked flask equipped with a stirrer, a thermometer, an air duct and a reflux condenser, introducing nitrogen protection, stirring the reaction for 1-1.5 hours at a temperature of 25-30° C. and a stirring rate of 300-400 r / min, then heating to reflux and continuing to stir the reaction for 10-15 hours, and after the reaction is completed, cooling the reaction product to room temperature, and then vacuum filtering, washing the filter cake with sulfuric acid solution and anhydrous ethanol for 3-5 times in sequence, and then placing it in a vacuum drying oven, and drying it at a temperature of 60-65° C. for 6-8 hours to obtain polyamino-modified silica;

[0011] Step a3: adding 2,2-dihydroxymethylpropionic acid, perfluoro-1-octanol, p-toluenesulfonic acid and anhydrous acetone into a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, introducing nitrogen protection, stirring the reaction for 15-20 minutes at a temperature of 5-10° C. and a stirring rate of 300-400 r / min, then heating to 120-130° C. and continuing to stir the reaction for 6-7 hours. After the reaction is completed, the reaction product is cooled to room temperature, then washed with sodium bicarbonate solution and distilled water 2-3 times in sequence, then dried with anhydrous magnesium sulfate, then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent 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, a thermometer and an air guide tube, introduce nitrogen protection, stir and react for 15-20 minutes at a temperature of 25-30°C and a stirring rate of 300-400r / min, then heat to 65-70°C and continue to stir and react for 1-2 hours, then heat to 90-95°C and continue to stir and react for 2-3 hours, then add fluorinated diol and continue to stir and react for 2-3 hours, then cool to 50-55°C and add triethylamine to adjust the pH to 6-6.5, then continue to stir and react for 30-40 minutes, then add deionized water and continue to stir and react for 20-30 minutes, adjust the solid content to 30-40%, and obtain a fluorinated modified emulsion;

[0013] Step a5: Add the polyamino-modified silica and the fluorine-modified emulsion into a three-necked flask equipped with a stirrer and a thermometer, stir and react for 15-20 minutes at a temperature of 25-30°C and a stirring rate of 300-400 r / min, then raise the temperature to 40-45°C and continue stirring and reacting for 15-20 hours. After the reaction is completed, cool the reaction product to room temperature to obtain a particle-modified emulsion.

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

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

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

[0017] As a further solution 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 solution of the present invention: the usage ratio of the 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 solution of the present invention: the mass fraction of the sodium bicarbonate solution in step a3 is 8-10%.

[0020] As a further solution of the present invention: the usage ratio of the 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 solution 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 solution of the present invention: the usage ratio of the polyamino-modified silica and the fluorine-containing modified emulsion in step a5 is 3-15g:100g.

[0023] As a further solution of the present invention: a method for preparing a light-transmitting coating for automobile exterior decoration parts comprises the following steps:

[0024] Step 1: Weigh 70-80 parts of particle modified latex, 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 weight, and set aside;

[0025] Step 2: Add the particle-modified latex, antioxidant, ultraviolet absorber, light stabilizer and leveling agent into the reactor, stir the reaction for 45-75 minutes at a temperature of 25-30°C and a stirring rate of 600-800r / min, and then filter with a 200-300 mesh filter to obtain a light-transmitting coating for automotive exterior decoration parts.

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

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

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

[0029] As a further solution of the present invention: a method for using a light-transmitting coating for an automobile exterior decorative part comprises the following steps:

[0030] The light-transmitting paint is sprayed on the automobile exterior decoration parts, and then placed in a forced air drying oven for baking and solidification into a coating.

[0031] Beneficial effects of the present invention:

[0032] The invention discloses a light-transmitting paint for automobile exterior decoration parts, a preparation method and a use method thereof. The light-transmitting paint for automobile exterior decoration parts is obtained by adding a particle-modified emulsion, an antioxidant, an ultraviolet absorber, a light stabilizer and a leveling agent into a reaction kettle, stirring for reaction, and then filtering. The light-transmitting paint for automobile exterior decoration parts uses the particle-modified emulsion as a main raw material, and optimizes the formula so that the paint has excellent light-transmitting performance, can provide a clear and bright visual effect for automobile exterior decoration parts, and improves the hardness and wear resistance of the coating, so that the automobile exterior decoration parts are not prone to scratches in daily use, and the service life is extended. The paint can effectively resist the erosion of environmental factors such as acid, alkali and moisture, prevent the coating from fading, powdering and the like, ensure that the coating will not fall off in various harsh environments, ensure the stability of color and gloss of automobile exterior decoration parts during long-term use, and ensure the durability of the decorative effect.

[0033] In the process of preparing the light-transmitting coating for automobile exterior decoration parts, a particle-modified emulsion is first prepared, nano-silica is treated with (3-chloropropyl) triethoxysilane, the siloxane on the (3-chloropropyl) triethoxysilane is hydrolyzed to form silanol and grafted to the particle surface of the nano-silica, and chlorine atoms are introduced at the same time to obtain silane-modified silica, 1,3,5-triaminobenzene is used to treat the silane-modified silica, the amino groups on the 1,3,5-triaminobenzene react with the chlorine atoms on the silane-modified silica, and a large number of amino groups are introduced at the same time to obtain polyamino-modified silica, and then 2,2-dihydroxymethylpropionic acid and perfluoro-1-octanol are reacted, the carboxyl groups on the 2,2-dihydroxymethylpropionic acid react with the hydroxyl groups on the perfluoro-1-octanol to form a diol containing a large amount of fluorine elements, and a fluorine-containing diol is obtained, and then polyether diol and toluene-2,4-diisocyanate are used as polymerization monomers for polymerization, and the fluorine-containing diol is used for polymerization. The alcohol is chain extended and polymerized to form a polymer with a polyurethane structure to obtain a fluorine-containing modified emulsion. Finally, polyamino-modified silica and the fluorine-containing modified emulsion are reacted. The amino groups on the polyamino-modified silica react with the isocyanate groups on the polymer in the fluorine-containing modified emulsion to connect the two in the form of a chemical bond to obtain a fluorine-containing modified emulsion. The polymer in the fluorine-containing modified emulsion contains a large amount of fluorine element, which gives the coating excellent water resistance and acid and alkali resistance, and at the same time gives the coating lubricity and improves its wear resistance. The addition of silica improves the mechanical properties of the coating and further improves the wear and scratch resistance of the coating. After modification, it can be evenly dispersed in the coating. The even dispersion has a smaller scattering ability for incident light, which ensures the light transmittance of the coating. In addition, the addition of polyamino-modified silica greatly improves the degree of cross-linking between polymers, thereby improving the density of the coating, further improving its comprehensive performance, and greatly giving the coating long-term stability. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Embodiment 1:

[0036] This embodiment is a method for preparing a light-transmitting coating for automobile exterior decoration parts, comprising the following steps:

[0037] Step S1: 1 g of nano-silica and 50 mL of 85% ethanol solution by volume were added to a three-necked flask equipped with a stirrer, a thermometer, an air duct and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred for reaction at 25° C. and a stirring rate of 300 r / min for 20 min, and then 0.8 g of (3-chloropropyl) triethoxysilane was added and the mixture was heated to reflux and continued to stir for reaction for 30 h. After the reaction was completed, the reaction product was cooled to room temperature, and then vacuum filtered. The filter cake was washed with anhydrous ethanol for 3 times, and then placed in a vacuum drying oven and dried at 80° C. for 3 h to obtain silane-modified silica;

[0038] Step S2: 1 g of silane-modified silica, 1.1 g of 1,3,5-triaminobenzene, 1.2 mL of triethylamine and 60 mL of chloroform were added to a three-necked flask equipped with a stirrer, a thermometer, a gas duct and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred for reaction at 25° C. and a stirring rate of 300 r / min for 1 h, and then the mixture was heated to reflux and continued to stir for 10 h. 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 a sulfuric acid solution having a molar concentration of 0.1 mol / L and anhydrous ethanol, and then placed in a vacuum drying oven and dried at 60° C. for 6 h to obtain polyamino-modified silica;

[0039] Step S3: adding 10 mmol 2,2-dihydroxymethylpropionic acid, 10 mmol perfluoro-1-octanol, 0.2 g p-toluenesulfonic acid and 50 mL anhydrous acetone to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, introducing nitrogen protection, stirring the reaction at a temperature of 5° C. and a stirring rate of 300 r / min for 15 min, then heating to 120° C. and continuing to stir the reaction for 6 h. After the reaction is completed, the reaction product is cooled to room temperature, then washed twice with a sodium bicarbonate solution with a mass fraction of 8% and distilled water in sequence, then dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a fluorinated diol;

[0040] Step S4: 40g of polyether diol, 20g of toluene-2,4-diisocyanate, 0.8g of dibutyltin dilaurate and 30mL of anhydrous acetone are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred and reacted for 15min at a temperature of 25°C and a stirring rate of 300r / min, and then the mixture is heated to 65°C and stirred and reacted for 1h, and then the mixture is heated to 90°C and stirred and reacted for 2h, and then 5g of fluorinated diol is added and stirred and reacted for 2h, and then the mixture is cooled to 50°C and triethylamine is added to adjust the pH to 6, and then the mixture is stirred and reacted for 30min, and then deionized water is added and stirred and reacted for 20min, and the solid content is adjusted to 30%, to obtain a fluorinated modified emulsion; the polyether diol is polypropylene glycol PPG-1000;

[0041] Step S5: adding 3 g of polyamino-modified silica and 100 g of fluorine-containing modified emulsion into a three-necked flask equipped with a stirrer and a thermometer, stirring the mixture for 15 min at a temperature of 25° C. and a stirring rate of 300 r / min, then heating the mixture to 40° C. and continuing stirring the mixture for 15 h. After the reaction, cooling the reaction product to room temperature to obtain a particle-modified emulsion.

[0042] Step S6: 70 parts of particle-modified latex, 1 part of antioxidant, 1 part of ultraviolet absorber, 0.6 parts of light stabilizer and 0.2 parts of leveling agent are weighed in parts by weight for later use; the antioxidant is antioxidant 300; the light stabilizer is light stabilizer 770; the leveling agent is leveling agent BYK306;

[0043] Step S7: Add the particle-modified latex, antioxidant, ultraviolet absorber, light stabilizer and leveling agent into the reactor, stir and react for 45 minutes at a temperature of 25° C. and a stirring rate of 600 r / min, and then filter with a 200-mesh filter to obtain a light-transmitting coating for automotive exterior decoration parts.

[0044] Embodiment 2:

[0045] This embodiment is a method for preparing a light-transmitting coating for automobile exterior decoration parts, comprising the following steps:

[0046] Step S1: 1 g of nano-silica and 55 mL of an ethanol solution with a volume fraction of 85% are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a reflux condenser, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 28° C. and a stirring rate of 350 r / min for 25 min, and then 1.5 g of (3-chloropropyl) triethoxysilane is added and the mixture is heated to reflux and stirred for reaction for 35 h. After the reaction is completed, the reaction product is cooled to room temperature, and then vacuum filtered. The filter cake is washed with anhydrous ethanol for 4 times, and then placed in a vacuum drying oven and dried at a temperature of 82° C. for 4 h to obtain silane-modified silica;

[0047] Step S2: 1 g of silane-modified silica, 1.6 g of 1,3,5-triaminobenzene, 1.4 mL of triethylamine and 65 mL of chloroform were added to a three-necked flask equipped with a stirrer, a thermometer, an air duct and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred for reaction at 28° C. and a stirring rate of 350 r / min for 1.2 h, and then the mixture was heated to reflux and continued to stir for 12 h. 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 a sulfuric acid solution having a molar concentration of 0.15 mol / L and anhydrous ethanol, and then placed in a vacuum drying oven and dried for 7 h at a temperature of 62° C. to obtain polyamino-modified silica;

[0048] Step S3: 10 mmol 2,2-dihydroxymethylpropionic acid, 10 mmol perfluoro-1-octanol, 0.25 g p-toluenesulfonic acid and 55 mL anhydrous acetone are added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 7° C. and a stirring rate of 350 r / min for 18 min, and then the mixture is heated to 125° C. and stirred for reaction for 6.5 h. After the reaction is completed, the reaction product is cooled to room temperature, and then washed twice with a sodium bicarbonate solution with a mass fraction of 9% and distilled water in sequence, and then dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a fluorinated diol;

[0049] Step S4: 45g of polyether diol, 20g of toluene-2,4-diisocyanate, 1.0g of dibutyltin dilaurate and 40mL of anhydrous acetone are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 28°C and a stirring rate of 350r / min for 18min, and then the mixture is heated to 68°C and stirred for reaction for 1.5h, and then the mixture is heated to 92°C and stirred for reaction for 2.5h, and then 9g of fluorinated diol is added and stirred for reaction for 2.5h, and then the mixture is cooled to 52°C and triethylamine is added to adjust the pH to 6, and then the mixture is stirred for reaction for 35min, and then deionized water is added and stirred for reaction for 25min, and the solid content is adjusted to 35%, to obtain a fluorinated modified emulsion; the polypropylene glycol PPG-600;

[0050] Step S5: adding 9 g of polyamino-modified silica and 100 g of fluorine-containing modified emulsion into a three-necked flask equipped with a stirrer and a thermometer, stirring the mixture for 18 min at a temperature of 28° C. and a stirring rate of 350 r / min, then heating the mixture to 42° C. and continuing stirring the mixture for 18 h. After the reaction, cooling the reaction product to room temperature to obtain a particle-modified emulsion;

[0051] Step S6: 75 parts of particle-modified latex, 2 parts of antioxidant, 2 parts of ultraviolet absorber, 0.9 parts of light stabilizer and 0.4 parts of leveling agent are weighed in parts by weight for later use; 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 latex, antioxidant, ultraviolet absorber, light stabilizer and leveling agent into the reactor, stir and react for 60 minutes at a temperature of 28° C. and a stirring rate of 700 r / min, and then filter with a 250-mesh filter to obtain a light-transmitting coating for automotive exterior decoration parts.

[0053] Embodiment 3:

[0054] This embodiment is a method for preparing a light-transmitting coating for automobile exterior decoration parts, comprising the following steps:

[0055] Step S1: 1 g of nano-silica and 60 mL of an ethanol solution with a volume fraction of 85% are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a reflux condenser, and nitrogen is introduced for protection. The mixture is stirred and reacted for 30 min at a temperature of 30° C. and a stirring rate of 400 r / min. Then, 2.2 g of (3-chloropropyl) triethoxysilane is added and the mixture is heated to reflux and stirred and reacted for 40 h. After the reaction is completed, the reaction product is cooled to room temperature and then vacuum filtered. The filter cake is washed with anhydrous ethanol for 5 times, and then placed in a vacuum drying oven and dried at a temperature of 85° C. for 5 h to obtain silane-modified silica;

[0056] Step S2: 1 g of silane-modified silica, 2.1 g of 1,3,5-triaminobenzene, 1.6 mL of triethylamine and 70 mL of chloroform were added to a three-necked flask equipped with a stirrer, a thermometer, an air duct and a reflux condenser, and nitrogen was introduced for protection. The mixture was stirred for reaction at 30° C. and a stirring rate of 400 r / min for 1.5 h, and then the mixture was heated to reflux and continued to stir for 15 h. After the reaction was completed, the reaction product was cooled to room temperature, and then vacuum filtered. The filter cake was washed 5 times with a sulfuric acid solution having a molar concentration of 0.2 mol / L and anhydrous ethanol, and then placed in a vacuum drying oven and dried at 65° C. for 8 h to obtain polyamino-modified silica;

[0057] Step S3: adding 10 mmol 2,2-dihydroxymethylpropionic acid, 10 mmol perfluoro-1-octanol, 0.3 g p-toluenesulfonic acid and 60 mL anhydrous acetone into a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, introducing nitrogen protection, stirring the reaction at a temperature of 10° C. and a stirring rate of 400 r / min for 20 min, then heating to 130° C. and continuing to stir the reaction for 7 h. After the reaction is completed, the reaction product is cooled to room temperature, and then washed with a sodium bicarbonate solution with a mass fraction of 10% and distilled water for 3 times, and then dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a fluorinated diol;

[0058] Step S4: 50g of polyether diol, 20g of toluene-2,4-diisocyanate, 1.2g of dibutyltin dilaurate and 50mL of anhydrous acetone are added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen is introduced for protection. The mixture is stirred and reacted for 20min at a temperature of 30°C and a stirring rate of 400r / min, and then the mixture is heated to 70°C and stirred and reacted for 2h, and then the mixture is heated to 95°C and stirred and reacted for 3h, and then 13g of fluorinated diol is added and stirred and reacted for 3h, and then the mixture is cooled to 55°C and triethylamine is added to adjust the pH to 6.5, and then the mixture is stirred and reacted for 40min, and then deionized water is added and stirred and reacted for 30min, and the solid content is adjusted to 40%, to obtain a fluorinated modified emulsion; the polyether diol is polyethylene glycol PEG-600;

[0059] Step S5: adding 15 g of polyamino-modified silica and 100 g of fluorine-containing modified emulsion into a three-necked flask equipped with a stirrer and a thermometer, stirring the mixture for 20 min at a temperature of 30° C. and a stirring rate of 400 r / min, then heating the mixture to 45° C. and continuing stirring the mixture for 20 h. After the reaction, cooling the reaction product to room temperature to obtain a particle-modified emulsion.

[0060] Step S6: 80 parts of particle modified latex, 3 parts of antioxidant, 3 parts of ultraviolet absorber, 1.2 parts of light stabilizer and 0.6 parts of leveling agent are weighed according to weight parts for standby use; 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 latex, antioxidant, ultraviolet absorber, light stabilizer and leveling agent into the reactor, stir and react for 75 minutes at a temperature of 30° C. and a stirring rate of 800 r / min, and then filter with a 300-mesh filter to obtain a light-transmitting coating for automotive exterior decoration parts.

[0062] Comparative Example 1:

[0063] This comparative example is a method for preparing a light-transmitting coating for automobile exterior decoration parts, comprising the following steps:

[0064] Step S1: 50g of polyether diol, 20g of toluene-2,4-diisocyanate, 1.2g of dibutyltin dilaurate and 50mL of anhydrous acetone are added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen is introduced for protection. The mixture is stirred and reacted for 20min at a temperature of 30°C and a stirring rate of 400r / min, and then the mixture is heated to 70°C and stirred and reacted for 2h, and then the mixture is heated to 95°C and stirred and reacted for 3h, and then the mixture is cooled to 55°C and triethylamine is added to adjust the pH to 6.5, and then the mixture is stirred and reacted for 40min, and then deionized water is added and stirred and reacted for 30min, and the solid content is adjusted to 40% to obtain a modified emulsion; the polyether diol is polyethylene glycol PEG-600;

[0065] Step S2: 80 parts of modified latex, 3 parts of antioxidant, 3 parts of ultraviolet absorber, 1.2 parts of light stabilizer and 0.6 parts of leveling agent are weighed according to weight parts for standby use; the antioxidant is antioxidant 1135; the light stabilizer is light stabilizer 770; the leveling agent is leveling agent BYK358;

[0066] Step S3: adding the modified emulsion, antioxidant, ultraviolet absorber, light stabilizer and leveling agent into the reactor, stirring the reaction for 75 minutes at a temperature of 30° C. and a stirring rate of 800 r / min, and then filtering with a 300-mesh filter to obtain a light-transmitting coating for automotive exterior decoration parts.

[0067] Comparative Example 2:

[0068] This comparative example is a method for preparing a light-transmitting coating for automobile exterior decoration parts, comprising the following steps:

[0069] Step S1: 10 mmol 2,2-dihydroxymethylpropionic acid, 10 mmol perfluoro-1-octanol, 0.3 g p-toluenesulfonic acid and 60 mL anhydrous acetone are added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 10° C. and a stirring rate of 400 r / min for 20 min, and then the mixture is heated to 130° C. and stirred for reaction for 7 h. After the reaction is completed, the reaction product is cooled to room temperature, and then washed with a sodium bicarbonate solution with a mass fraction of 10% and distilled water for 3 times, and then dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a fluorinated diol;

[0070] Step S2: 50g of polyether diol, 20g of toluene-2,4-diisocyanate, 1.2g of dibutyltin dilaurate and 50mL of anhydrous acetone are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred and reacted for 20min at a temperature of 30°C and a stirring rate of 400r / min, and then the mixture is heated to 70°C and stirred and reacted for 2h, and then the mixture is heated to 95°C and stirred and reacted for 3h, and then 13g of fluorinated diol is added and stirred and reacted for 3h, and then the mixture is cooled to 55°C and triethylamine is added to adjust the pH to 6.5, and then the mixture is stirred and reacted for 40min, and then deionized water is added and stirred and reacted for 30min, and the solid content is adjusted to 40%, to obtain a fluorinated modified emulsion; the polyether diol is polyethylene glycol PEG-600;

[0071] Step S3: 80 parts of fluorine-containing modified latex, 3 parts of antioxidant, 3 parts of ultraviolet absorber, 1.2 parts of light stabilizer and 0.6 parts of leveling agent are weighed according to weight parts for standby use; the antioxidant is antioxidant 1135; the light stabilizer is light stabilizer 770; the leveling agent is leveling agent BYK358;

[0072] Step S4: adding the fluorine-containing modified emulsion, antioxidant, ultraviolet absorber, light stabilizer and leveling agent into the reactor, stirring the reaction for 75 minutes at a temperature of 30° C. and a stirring rate of 800 r / min, and then filtering with a 300-mesh filter to obtain a light-transmitting coating for automotive exterior decoration parts.

[0073] Comparative Example 3:

[0074] This comparative example is a method for preparing a light-transmitting coating for automobile exterior decoration parts, comprising the following steps:

[0075] Step S1: 10 mmol 2,2-dihydroxymethylpropionic acid, 10 mmol perfluoro-1-octanol, 0.3 g p-toluenesulfonic acid and 60 mL anhydrous acetone are added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 10° C. and a stirring rate of 400 r / min for 20 min, and then the mixture is heated to 130° C. and stirred for reaction for 7 h. After the reaction is completed, the reaction product is cooled to room temperature, and then washed with a sodium bicarbonate solution with a mass fraction of 10% and distilled water for 3 times, and then dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a fluorinated diol;

[0076] Step S2: 50g of polyether diol, 20g of toluene-2,4-diisocyanate, 1.2g of dibutyltin dilaurate and 50mL of anhydrous acetone are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred and reacted for 20min at a temperature of 30°C and a stirring rate of 400r / min, and then the mixture is heated to 70°C and stirred and reacted for 2h, and then the mixture is heated to 95°C and stirred and reacted for 3h, and then 13g of fluorinated diol is added and stirred and reacted for 3h, and then the mixture is cooled to 55°C and triethylamine is added to adjust the pH to 6.5, and then the mixture is stirred and reacted for 40min, and then deionized water is added and stirred and reacted for 30min, and the solid content is adjusted to 40%, to obtain a fluorinated modified emulsion; the polyether diol is polyethylene glycol PEG-600;

[0077] Step S3: adding 15 g of nano-silicon dioxide and 100 g of fluorine-containing modified emulsion into a three-necked flask equipped with a stirrer and a thermometer, stirring the mixture for 20 min at a temperature of 30° C. and a stirring rate of 400 r / min, then heating the mixture to 45° C. and continuing the stirring reaction for 20 h. After the reaction is completed, the reaction product is cooled to room temperature to obtain a particle-modified emulsion;

[0078] Step S4: 80 parts of particle modified latex, 3 parts of antioxidant, 3 parts of ultraviolet absorber, 1.2 parts of light stabilizer and 0.6 parts of leveling agent are weighed in parts by weight for later use; 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 latex, antioxidant, ultraviolet absorber, light stabilizer and leveling agent into the reactor, stir and react for 75 minutes at a temperature of 30° C. and a stirring rate of 800 r / min, and then filter with a 300-mesh filter to obtain a light-transmitting coating for automotive exterior decoration parts.

[0080] Comparative Example 4:

[0081] This comparative example is a method for preparing a light-transmitting coating for automobile exterior decoration parts, comprising the following steps:

[0082] Step S1: 1 g of nano-silica and 60 mL of an ethanol solution with a volume fraction of 85% are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a reflux condenser, and nitrogen is introduced for protection. The mixture is stirred and reacted for 30 min at a temperature of 30° C. and a stirring rate of 400 r / min. Then, 2.2 g of (3-chloropropyl) triethoxysilane is added and the mixture is heated to reflux and stirred and reacted for 40 h. After the reaction is completed, the reaction product is cooled to room temperature and then vacuum filtered. The filter cake is washed with anhydrous ethanol for 5 times, and then placed in a vacuum drying oven and dried at a temperature of 85° C. for 5 h to obtain silane-modified silica;

[0083] Step S2: 10 mmol 2,2-dihydroxymethylpropionic acid, 10 mmol perfluoro-1-octanol, 0.3 g p-toluenesulfonic acid and 60 mL anhydrous acetone are added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 10° C. and a stirring rate of 400 r / min for 20 min, and then the mixture is heated to 130° C. and the stirring reaction is continued for 7 h. After the reaction is completed, the reaction product is cooled to room temperature, and then washed with a sodium bicarbonate solution with a mass fraction of 10% and distilled water for 3 times in sequence, and then dried with anhydrous magnesium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a fluorinated diol;

[0084] Step S3: 50g of polyether diol, 20g of toluene-2,4-diisocyanate, 1.2g of dibutyltin dilaurate and 50mL of anhydrous acetone are added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen is introduced for protection. The mixture is stirred and reacted for 20min at a temperature of 30°C and a stirring rate of 400r / min, and then the mixture is heated to 70°C and stirred and reacted for 2h, and then the mixture is heated to 95°C and stirred and reacted for 3h, and then 13g of fluorinated diol is added and stirred and reacted for 3h, and then the mixture is cooled to 55°C and triethylamine is added to adjust the pH to 6.5, and then the mixture is stirred and reacted for 40min, and then deionized water is added and stirred and reacted for 30min, and the solid content is adjusted to 40%, to obtain a fluorinated modified emulsion; the polyether diol is polyethylene glycol PEG-600;

[0085] Step S4: adding 15 g of silane-modified silica and 100 g of fluorine-containing modified emulsion into a three-necked flask equipped with a stirrer and a thermometer, stirring the mixture for 20 min at a temperature of 30° C. and a stirring rate of 400 r / min, then heating the mixture to 45° C. and continuing stirring the mixture for 20 h. After the reaction, cooling the reaction product to room temperature to obtain a particle-modified emulsion;

[0086] Step S5: 80 parts of particle modified latex, 3 parts of antioxidant, 3 parts of ultraviolet absorber, 1.2 parts of light stabilizer and 0.6 parts of leveling agent are weighed according to weight parts for standby use; 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 latex, antioxidant, ultraviolet absorber, light stabilizer and leveling agent into the reactor, stir and react for 75 minutes at a temperature of 30° C. and a stirring rate of 800 r / min, and then filter with a 300-mesh filter to obtain a light-transmitting coating for automotive exterior decoration parts.

[0088] The light-transmitting coatings for automobile exterior decoration parts of Examples 1-3 and Comparative Examples 1-4 were sprayed on Q235 steel plates using a W-101 spray gun, and the dry film thickness was controlled to 100 μm. They were then placed in a forced air drying oven and baked at 80°C for 6 hours. After curing into a coating, they were taken out and naturally cooled for 24 hours for coating performance testing.

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

[0090]

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

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

[0093] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0094] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined in this application, they shall all fall within the protection scope of the present invention.

Claims

1. A light-transmitting paint for automobile exterior decoration, characterized in that: It comprises the following components in parts by weight: 70-80 parts of particle modified latex, 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; Wherein, the particle-modified latex is prepared by the following steps: Step a1: stirring the nano-silica and ethanol solution to react, then adding (3-chloropropyl)triethoxysilane and continuing to stir the reaction, cooling the reaction product after the reaction is completed, then vacuum filtering, washing and drying the filter cake to obtain silane-modified silica; Step a2: stirring silane-modified silica, 1,3,5-triaminobenzene, triethylamine and chloroform to react, cooling the reaction product after the reaction is completed, and then vacuum filtering, washing and drying the filter cake to obtain polyamino-modified silica; Step a3: stirring 2,2-dihydroxymethylpropionic acid, perfluoro-1-octanol, p-toluenesulfonic acid and anhydrous acetone for reaction, cooling the reaction product after the reaction is completed, then washing and drying, and then vacuum filtering, and rotary evaporating the filtrate to obtain a fluorinated diol; Step a4: stirring and reacting polyether diol, toluene-2,4-diisocyanate, dibutyltin dilaurate and anhydrous acetone, then adding fluorinated diol and continuing stirring and reacting, then adjusting the pH with triethylamine, then adding deionized water and continuing stirring and reacting to obtain a fluorinated modified emulsion; Step a5: stirring the polyamino-modified silica and the fluorine-containing modified latex to react, and cooling the reaction product after the reaction is completed to obtain a particle-modified latex.

2. A light-transmitting paint for automobile exterior decoration according to claim 1, characterized in that: The usage ratio of the nano-silica, ethanol solution and (3-chloropropyl)triethoxysilane in step a1 is 1 g: 50-60 mL: 0.8-2.2 g; the volume fraction of the ethanol solution is 85%.

3. The light-transmitting paint for automobile exterior decoration according to claim 1, characterized in that: The usage ratio of the silane-modified silica, 1,3,5-triaminobenzene, triethylamine and chloroform in step a2 is 1 g: 1.1-2.1 g: 1.2-1.6 mL: 60-70 mL.

4. The light-transmitting paint for automobile exterior decoration according to claim 1, characterized in that: The usage ratio of the 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.

5. The light-transmitting paint for automobile exterior decoration according to claim 1, characterized in that: The usage ratio of the 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; the polyether diol is one of polypropylene glycol PPG-1000, polypropylene glycol PPG-600 and polyethylene glycol PEG-600.

6. The light-transmitting paint for automobile exterior decoration according to claim 1, characterized in that: The usage ratio of the polyamino-modified silica and the fluorine-containing modified emulsion in step a5 is 3-15g:100g.

7. A method for preparing a light-transmitting coating for automobile exterior decoration parts according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Weigh 70-80 parts of particle modified latex, 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 weight, and set aside; Step 2: Add the particle-modified latex, antioxidant, ultraviolet absorber, light stabilizer and leveling agent into the reactor, stir the reaction for 45-75 minutes at a temperature of 25-30°C and a stirring rate of 600-800r / min, and then filter with a 200-300 mesh filter to obtain a light-transmitting coating for automotive exterior decoration parts.

8. The method for preparing a light-transmitting coating for automobile exterior decoration 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 light-transmitting coating for automobile exterior decoration according to claim 7, characterized in that: The leveling agent is one of leveling agent BYK306, leveling agent BYK331 and leveling agent BYK358.

10. A method for using a light-transmitting paint for automobile exterior decoration parts prepared by the method for preparing a light-transmitting paint for automobile exterior decoration parts according to any one of claims 7 to 9, characterized in that: The following steps are involved: The light-transmitting paint is sprayed on the automobile exterior decoration parts, and then placed in a forced air drying oven for baking and solidification into a coating.

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