Composite acrylic resin and application thereof in automobile painting

Abstract

The invention discloses composite acrylic resin and application thereof in automobile painting, and belongs to the technical field of composite acrylic resin preparation. The invention discloses composite acrylic resin. The anti-aging coating is prepared from the following components in parts by weight: 40 to 55 parts of methyl methacrylate, 20 to 25 parts of styrene, 32 to 45 parts of butyl acrylate, 18 to 26 parts of ethyl acrylate, 2 to 5 parts of glycidyl methacrylate, 0.2 to 0.6 part of azodiisobutyronitrile, 30 to 46 parts of distilled water, 10 to 14 parts of ethylene glycol, 0.7 to 1.2 parts of a composite anti-aging agent, 0.9 to 1.4 parts of a composite reinforcing agent and 0.5 to 1 part of a dispersing agent. 0.1 to 0.5 part of a defoaming agent and 0.1 to 0.4 part of an antioxidant. The composite acrylic resin prepared by the method has excellent adhesive force and chemical corrosion resistance.

Description

Technical Field

[0001] This invention belongs to the field of composite resin preparation technology, specifically relating to composite acrylic resin and its application in automotive coatings. Background Technology

[0002] Composite acrylic resins, as an important material in automotive coatings, are widely used due to their excellent lightfastness, chemical resistance, and good mechanical properties. However, they still face challenges in weather resistance during practical applications. While traditional acrylic resins can resist ultraviolet radiation and slow down paint aging, under extreme climatic conditions, such as prolonged exposure to strong ultraviolet radiation, high temperature and humidity, or severe cold, their films are prone to problems such as loss of gloss, chalking, and discoloration, affecting the durability of the vehicle's appearance. Furthermore, the "hot-sticky, cold-brittle" characteristic of acrylic resins makes them susceptible to cracking or peeling during sudden temperature changes. Although modification with epoxy resins and silicones can partially improve their overall performance, the complexity and cost of the modification process limit their large-scale application. Therefore, developing composite acrylic resins that combine high weather resistance with cost-effectiveness remains a key technological direction that urgently needs to be addressed in the automotive coatings industry.

[0003] Patent CN114958157B discloses an acrylic resin paint, a composite paint structure, and its preparation method. By weight, the acrylic resin paint comprises the following components: 15-30 parts acrylic resin A, 15-20 parts acrylic resin B, 5-15 parts anti-sagging resin, 20-30 parts polyester resin, 5-15 parts amino resin A, 5-15 parts amino resin B, 1-3 parts dispersant, 0.5-4 parts anti-settling agent, 5-10 parts filler, and 22-40 parts solvent. The molecular weight of acrylic resin A is 500,000-80,000, the molecular weight of acrylic resin B is 1,000-20,000, the molecular weight of amino resin A is 3,000-4,000, and the molecular weight of amino resin B is 1,000-2,000. The solvent includes diethylene glycol butyl ether. After spraying, this acrylic resin paint does not require separate baking; a topcoat is applied followed by baking, and its basic properties still meet the requirements. While the acrylic resin paint prepared using the above method offers advantages such as not requiring separate baking and being treated uniformly with the topcoat, it still suffers from insufficient weather resistance as an automotive coating. Under long-term outdoor exposure, the paint film is prone to gloss degradation, surface chalking, and even localized cracking due to factors such as ultraviolet radiation, alternating temperature and humidity changes, and industrial air pollution. This is mainly because the molecular weight distribution of its acrylic resin components varies significantly. While lower molecular weight components improve application performance, they reduce the film's density, limiting its impermeability and weather resistance, making it difficult to meet the long-term protective requirements of automotive coatings. Summary of the Invention

[0004] The purpose of this invention is to provide composite acrylic resin and its application in automotive coatings, in order to solve the technical problems of poor adhesion and weather resistance of composite acrylic resin in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a composite acrylic resin, composed of the following components by weight: 40-55 parts methyl methacrylate, 20-25 parts styrene, 32-45 parts butyl acrylate, 18-26 parts ethyl acrylate, 2-5 parts glycidyl methacrylate, 0.2-0.6 parts azobisisobutyronitrile, 30-46 parts distilled water, 10-14 parts ethylene glycol, 0.7-1.2 parts composite anti-aging agent, 0.9-1.4 parts composite reinforcing agent, 0.5-1 part dispersant, 0.1-0.5 parts defoamer, and 0.1-0.4 parts antioxidant.

[0006] Preferably, the preparation method of the composite anti-aging agent includes the following steps: Q1: 7-hydroxy-4-methoxyisophenyl ketone, potassium carbonate and methanol were added to a container in sequence. After heating and stirring, 1,12-dibromododecane was added to continue the reaction. After the reaction was completed, the mixture was rotary evaporated, distilled water was added, and a solid was precipitated. The solid was filtered, washed, dried, dispersed and filtered again to obtain organic compound 1. Q2: Add 1-tert-butoxycarbonyl-4-methylaminopiperidine, potassium carbonate, potassium iodide and acetonitrile to a container, stir at room temperature, add organic compound 1, heat and react, filter, wash, collect the filtrate and evaporate by rotary evaporation to purify, to obtain organic compound 2. Q3: Add organic compound 2 to a container containing methanol, stir, add hydrochloric acid, heat to reflux and react, rotary evaporate, add to distilled water, adjust pH, extract, collect organic phase, rotary evaporate, and obtain composite anti-aging agent.

[0007] The synthesis reaction formula for the composite anti-aging agent in the above process is as follows:

[0008] The mass spectrometry analysis results of organic compound 1 were: m / z: 514.17 (100.0%), 516.17 (97.3%), 515.18 (30.8%), 517.17 (29.6%), 516.18 (5.4%), 518.18 (4.5%), 517.18 (1.1%); the mass spectrometry analysis results of organic compound 2 were: m / z: 648.41 (100.0%), 649.42 (43.1%), 650.42 (10.3%), 651.42 (1.8%); the mass spectrometry analysis results of the composite anti-aging agent were: m / z: 548.36 (100.0%), 549.36 (37.5%), 550.37 (7.6%), 551.37. (1.2%).

[0009] Preferably, in Q1, the molar ratio of 7-hydroxy-4-methoxyisophenyl ketone, potassium carbonate, methanol, and 1,12-dibromododecane is (3.2-4.3) g : (4.11-5.28) g : (80-95) mL : (3.54-3.68) g. The mixture is heated to 80-84℃ and stirred for 30-45 min, and the reaction continues for 6-10 h. The mixture is then washed successively with distilled water and petroleum ether, and finally, 60 mL of a mixture of petroleum ether and acetic acid in a volume ratio of 3:1 is added. The mixed solution of ethyl ester was dispersed for 10-12 h; in Q2, the ratio of 1-tert-butylcarbonyl-4-methylaminopiperidine, potassium carbonate, potassium iodide, acetonitrile and organic compound 1 was (1.42-1.88) g : (5.11-5.65) g : (0.21-0.28) g : (80-100) mL : (1.2-1.8) g. The mixture was stirred at room temperature for 30-45 min, heated to 80-83℃ and reacted for 8-10 h, and then washed with dichloromethane.

[0010] Preferably, in Q3, the ratio of organic compound 2, methanol and hydrochloric acid is (2.12-2.47) g : (50-76) mL : (5.2-7.7) mL, the concentration of hydrochloric acid is 1 mol / L, the reaction is heated to 60-63℃ and refluxed for 2-4 h, the pH is adjusted to 8-9 with 5 wt% sodium bicarbonate aqueous solution, and the mixture is extracted with dichloromethane.

[0011] Preferably, the preparation method of the composite reinforcing agent includes the following steps: S1: 2,4-Dinitrotoluene and benzaldehyde were added to a container, followed by N,N-dimethylformamide. Under nitrogen protection, diazabicyclopropionate was added at low temperature to carry out the reaction. After the reaction was completed, the product was washed, extracted, dried, and concentrated to obtain product a. Product a, 2-iodobenzoic acid, and ethyl acetate were added to a container and heated under reflux. After the reaction was completed, the product was filtered, washed, concentrated, and recrystallized to obtain product b. S2: Add product b to a container containing anhydrous acetonitrile, stir, then add diazabicyclohexane and N-fluoro-N'-(chloromethyl)triethylenediaminebis(tetrafluoroborate) in sequence, stir the reaction at room temperature, and after the reaction is complete, wash, extract, dry, concentrate, and purify to obtain product c; S3: Under a nitrogen atmosphere, product c, palladium on carbon and anhydrous ethanol were added to a container, heated and hydrazine hydrate was added, the reaction was carried out, then filtered, cooled, washed, recrystallized, filtered, and vacuum dried to obtain product d. S4: Under nitrogen atmosphere, product d is added to a container containing N,N-dimethylformamide, stirred and mixed, then diphenylmethane-4,4'-diisocyanate is added, and the mixture is heated to react. After the reaction is complete, the product is added to distilled water, washed, and dried to obtain the composite reinforcing agent.

[0012] The synthesis reaction formula for the composite reinforcing agent in the above process is as follows:

[0013] The mass spectrometry analysis results for product a were: m / z: 288.07 (100.0%), 289.08 (15.5%), 290.08 (2.3%); for product b: m / z: 286.06 (100.0%), 287.06 (16.1%), 288.06 (1.1%), 288.07 (1.1%); for product c: m / z: 322.04 (100.0%), 323.04 (16.1%), 324.04 (1.1%), 324.05 (1.1%); and for product d: m / z: 262.09 (100.0%), 263.10 (15.3%), 264.10. (1.3%).

[0014] Preferably, in S1, the ratio of 2,4-dinitrotoluene, benzaldehyde, N,N-dimethylformamide, and diazabicyclohexane is (1.5-2.1) g : (1.2-1.9) g : (10-12) mL : (0.25-0.35) mL, the low-temperature environment is -30~-20℃, the reaction time is 48-52 h, the product is washed with saturated sodium chloride, and extracted with ethyl acetate; the ratio of product a, 2-iodobenzoic acid, and ethyl acetate is (1.5-1.92) g : (3.21-3.63) g : (20-30) mL, the reflux reaction temperature is 80-85℃, the reflux reaction time is 10-12 h, the product is washed with ethyl acetate, and recrystallized with ethanol.

[0015] Preferably, in step S2, the ratio of product b, anhydrous acetonitrile, diazabicyclohexane, and N-fluoro-N'-(chloromethyl)triethylenediamine bis(tetrafluoroborate) is (1.2-1.88) g : (30-45) mL : (1.5-1.82) mL : (3.98-4.22) g, the stirring time is 30-45 min, the reaction time is 2-4 h, and the product is washed with saturated ammonium chloride solution. In step S3, the ratio of product c, palladium on carbon, anhydrous ethanol, and hydrazine hydrate is (70-72.6) g : (2-3.2) g : (200-220) mL : (90-97.4) g, the temperature is raised to 80-83℃, and the reaction is carried out for 2-3 h.

[0016] Preferably, in step S3, the ratio of product d, N,N-dimethylformamide and diphenylmethane-4,4'-diisocyanate is (3.12-3.48) g : (45-53) mL : (2.28-2.95) g, and the reaction is carried out at 80-84°C for 8-12 h.

[0017] Preferably, the method for preparing the composite acrylic resin includes the following steps: Step 1: Add methyl methacrylate, styrene, butyl acrylate, ethyl acrylate and glycidyl methacrylate to a container filled with distilled water, then slowly add the dispersant and stir to mix to obtain a mixture. Step 2: Under nitrogen atmosphere, heat the mixture, then slowly add azobisisobutyronitrile (AIBN), stir and mix, keep the mixture at the desired temperature, cool, and then add ethylene glycol, composite anti-aging agent, composite reinforcing agent, defoamer and antioxidant in sequence. Continue stirring, adjust the pH, cool, and filter to obtain composite acrylic resin.

[0018] As a preferred application, the composite acrylic resin is used in automotive coatings.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention adds the prepared composite anti-aging agent and composite reinforcing agent to the composite acrylic resin and uses it as an automotive paint, which can effectively improve the adhesion, weather resistance, mechanical properties and chemical resistance of the paint.

[0020] 2. This invention adds the obtained composite anti-aging agent to a composite acrylic resin and applies it to automotive paint. This effectively improves the paint's weather resistance, oxidation resistance, and adhesion. The aromatic ethers and long-chain alkyl structures contained in the composite anti-aging agent can absorb ultraviolet light and convert it into heat energy through intramolecular excited-state energy transfer, preventing polymer breakage. The amino and ether bonds contained in the composite anti-aging agent can capture free radicals, block oxidation chain reactions, and delay polymer degradation. At the same time, the long-chain alkyl groups can insert into the resin molecular chains, increasing intermolecular forces, improving adhesion, and forming a hydrophobic interface to enhance chemical corrosion resistance.

[0021] 3. The present invention adds the prepared composite reinforcing agent to the composite acrylic resin, which can effectively improve its adhesion, mechanical properties and chemical corrosion resistance. The double bond cross-linking structure contained in the composite reinforcing agent significantly increases the cross-linking density of the coating, forms a three-dimensional network structure, enhances the mechanical properties of the coating, and the introduced fluorine atoms endow the coating with low surface energy characteristics, form a hydrophobic barrier, and improve chemical corrosion resistance. The contained polar groups can form strong interactions with the metal substrate, and improve adhesion. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1: This example discloses a method for preparing a composite anti-aging agent, including the following steps: Q1: 3.7g of 7-hydroxy-4-methoxyisophenyl ketone, 4.64g of potassium carbonate and 87mL of methanol were added to a container in sequence. The mixture was heated to 82℃ and stirred for 30min. Then, 3.61g of 1,12-dibromododecane was added and the reaction was continued for 10h. After the reaction was completed, the mixture was rotary evaporated, distilled water was added, and a solid was precipitated. The solid was filtered and washed with distilled water and petroleum ether in sequence. After drying, the solid was added to 60mL of a mixed solution of petroleum ether and ethyl acetate with a volume ratio of 3:1 and dispersed for 12h. After filtration, organic compound 1 was obtained. Q2: Add 1.65g of 1-tert-butoxycarbonyl-4-methylaminopiperidine, 5.33g of potassium carbonate, 0.24g of potassium iodide and 90mL of acetonitrile to a container, stir at room temperature for 30min, add 1.5g of organic compound 1, heat to 80℃ and react for 10h, filter, wash with dichloromethane, collect the filtrate and evaporate by rotary evaporation to purify, to obtain organic compound 2; Q3: Add 2.27g of organic compound 2 to a container containing 68mL of methanol, stir, add 6.4mL of 1mol / L hydrochloric acid, heat to 60℃ and reflux for 4h, rotary evaporate, add to distilled water, adjust pH to 8 with 5vt% sodium bicarbonate aqueous solution, extract with dichloromethane, collect the organic phase, rotary evaporate, and obtain the composite anti-aging agent.

[0024] This embodiment discloses a method for preparing a composite reinforcing agent, including the following steps: S1: 1.8 g of 2,4-dinitrotoluene and 1.55 g of benzaldehyde were added to a container, followed by 11 mL of N,N-dimethylformamide. Under nitrogen protection, 0.3 mL of diazabicyclopropionate was added and the reaction was carried out at -20 °C for 48 h. After the reaction was completed, the product was washed with saturated sodium chloride, extracted with ethyl acetate, dried, and concentrated to obtain product a. 1.71 g of product a, 3.42 g of 2-iodobenzoic acid, and 25 mL of ethyl acetate were added to a container and the mixture was heated to reflux at 82 °C for 12 h. After the reaction was completed, the product was filtered, washed with ethyl acetate, concentrated, and recrystallized with ethanol to obtain product b. S2: 1.54 g of product b was added to a container containing 37.5 mL of anhydrous acetonitrile. After stirring for 30 min, 1.68 mL of diazabicyclohexane and 4.12 g of N-fluoro-N'-(chloromethyl)triethylenediaminebis(tetrafluoroborate) were added sequentially. The mixture was stirred at room temperature for 2 h. After the reaction was completed, the product was washed with saturated ammonium chloride solution, extracted, dried, concentrated, and purified to obtain product c. S3: Under a nitrogen atmosphere, 71.3 g of product c, 2.6 g of palladium on carbon and 210 mL of anhydrous ethanol were added to a container. After heating to 80 °C, 93.7 g of hydrazine hydrate was added. The reaction was carried out for 2 h, followed by filtration, cooling, washing, recrystallization, filtration, and vacuum drying to obtain product d. S4: Under nitrogen atmosphere, 3.3g of product d was added to a container containing 49mL of N,N-dimethylformamide. After stirring and mixing, 2.54g of diphenylmethane-4,4'-diisocyanate was added, and the mixture was heated to 80℃ and reacted for 12h. After the reaction was completed, the product was added to distilled water, washed, and dried to obtain the composite reinforcing agent.

[0025] This embodiment discloses a composite acrylic resin, which is composed of the following components by weight: 47.5 parts methyl methacrylate, 22.5 parts styrene, 38 parts butyl acrylate, 22 parts ethyl acrylate, 3.5 parts glycidyl methacrylate, 0.4 parts azobisisobutyronitrile, 38 parts distilled water, 12 parts ethylene glycol, 0.85 parts composite anti-aging agent, 1.1 parts composite reinforcing agent, 0.75 parts dispersant, 0.3 parts defoamer, and 0.25 parts antioxidant.

[0026] This embodiment discloses a method for preparing a composite acrylic resin, including the following steps: Step 1: Add methyl methacrylate, styrene, butyl acrylate, ethyl acrylate and glycidyl methacrylate to a container filled with distilled water, then slowly add the dispersant and stir to mix to obtain a mixture. Step 2: Under nitrogen atmosphere, heat the mixture, then slowly add azobisisobutyronitrile (AIBN), stir and mix, keep the mixture at the temperature, cool, and then add ethylene glycol, composite anti-aging agent, composite reinforcing agent, defoamer and antioxidant in sequence. Continue stirring, adjust the pH to 7, cool, filter, and obtain composite acrylic resin.

[0027] Example 2: This example discloses a method for preparing a composite anti-aging agent, including the following steps: Q1: 3.2g of 7-hydroxy-4-methoxyisophenyl ketone, 4.11g of potassium carbonate and 80mL of methanol were added to a container in sequence. The mixture was heated to 82℃ and stirred for 30min. Then, 3.54g of 1,12-dibromododecane was added and the reaction was continued for 10h. After the reaction was completed, the mixture was rotary evaporated, distilled water was added, and a solid was precipitated. The solid was filtered and washed with distilled water and petroleum ether in sequence. After drying, the solid was added to 60mL of a mixed solution of petroleum ether and ethyl acetate with a volume ratio of 3:1 and dispersed for 12h. After filtration, organic compound 1 was obtained. Q2: Add 1.42g of 1-tert-butoxycarbonyl-4-methylaminopiperidine, 5.11g of potassium carbonate, 0.1g of potassium iodide and 80mL of acetonitrile to a container, stir at room temperature for 30min, add 1.8g of organic compound 1, heat to 80℃ and react for 10h, filter, wash with dichloromethane, collect the filtrate and evaporate by rotary evaporation to purify, to obtain organic compound 2; Q3: Add 2.12g of organic compound 2 to a container containing 50mL of methanol, stir, add 5.2mL of 1mol / L hydrochloric acid, heat to 60℃ and reflux for 4h, rotary evaporate, add to distilled water, adjust pH to 8 with 5vt% sodium bicarbonate aqueous solution, extract with dichloromethane, collect the organic phase, rotary evaporate, and obtain the composite anti-aging agent.

[0028] This embodiment discloses a method for preparing a composite reinforcing agent, including the following steps: S1: 1.5 g of 2,4-dinitrotoluene and 1.2 g of benzaldehyde were added to a container, followed by 10 mL of N,N-dimethylformamide. Under nitrogen protection, 0.35 mL of diazabicyclopropane was added and the reaction was carried out at -20 °C for 48 h. After the reaction was completed, the product was washed with saturated sodium chloride, extracted with ethyl acetate, dried, and concentrated to obtain product a. 1.5 g of product a, 3.21 g of 2-iodobenzoic acid, and 30 mL of ethyl acetate were added to a container and the mixture was heated to reflux at 82 °C for 12 h. After the reaction was completed, the product was filtered, washed with ethyl acetate, concentrated, and recrystallized with ethanol to obtain product b. S2: Add 1.2g of product b to a container containing 45mL of anhydrous acetonitrile, stir for 30min, then add 1.5mL of diazabicyclohexane and 3.98g of N-fluoro-N'-(chloromethyl)triethylenediaminebis(tetrafluoroborate) in sequence, stir at room temperature for 2h, after the reaction is complete, wash with saturated ammonium chloride solution, extract, dry, concentrate and purify to obtain product c; S3: Under a nitrogen atmosphere, 70g of product c, 2g of palladium on carbon and 220mL of anhydrous ethanol were added to a container, heated to 80℃ and then 90g of hydrazine hydrate was added. The reaction was carried out for 2h, followed by filtration, cooling, washing, recrystallization, filtration and vacuum drying to obtain product d. S4: Under nitrogen atmosphere, 3.12 g of product d was added to a container containing 45 mL of N,N-dimethylformamide. After stirring and mixing, 2.28 g of diphenylmethane-4,4'-diisocyanate was added. The mixture was heated to 80 °C and reacted for 12 h. After the reaction was completed, the product was added to distilled water, washed, and dried to obtain the composite reinforcing agent.

[0029] This embodiment discloses a composite acrylic resin, which is composed of the following components by weight: 40 parts methyl methacrylate, 20 parts styrene, 32 parts butyl acrylate, 18 parts ethyl acrylate, 2 parts glycidyl methacrylate, 0.6 parts azobisisobutyronitrile, 30 parts distilled water, 14 parts ethylene glycol, 0.7 parts composite anti-aging agent, 0.9 parts composite reinforcing agent, 1 part dispersant, 0.1 part defoamer, and 0.1 part antioxidant.

[0030] This embodiment discloses a method for preparing a composite acrylic resin, including the following steps: Step 1: Add methyl methacrylate, styrene, butyl acrylate, ethyl acrylate and glycidyl methacrylate to a container filled with distilled water, then slowly add the dispersant and stir to mix to obtain a mixture. Step 2: Under nitrogen atmosphere, heat the mixture, then slowly add azobisisobutyronitrile (AIBN), stir and mix, keep the mixture at the temperature, cool, and then add ethylene glycol, composite anti-aging agent, composite reinforcing agent, defoamer and antioxidant in sequence. Continue stirring, adjust the pH to 7, cool, filter, and obtain composite acrylic resin.

[0031] Example 3: This example discloses a method for preparing a composite anti-aging agent, including the following steps: Q1: 4.3g of 7-hydroxy-4-methoxyisophenyl ketone, 5.28g of potassium carbonate and 95mL of methanol were added to a container in sequence. The mixture was heated to 82℃ and stirred for 30min. Then, 3.68g of 1,12-dibromododecane was added and the reaction was continued for 10h. After the reaction was completed, the mixture was rotary evaporated, distilled water was added, and a solid was precipitated. The solid was filtered and washed with distilled water and petroleum ether in sequence. After drying, the solid was added to 60mL of a mixed solution of petroleum ether and ethyl acetate with a volume ratio of 3:1 and dispersed for 12h. After filtration, organic compound 1 was obtained. Q2: Add 1.88g of 1-tert-butoxycarbonyl-4-methylaminopiperidine, 5.65g of potassium carbonate, 0.28g of potassium iodide and 100mL of acetonitrile to a container, stir at room temperature for 30min, add 1.2g of organic compound 1, heat to 80℃ and react for 10h, filter, wash with dichloromethane, collect the filtrate and evaporate by rotary evaporation to purify, to obtain organic compound 2; Q3: Add 2.47g of organic compound 2 to a container containing 76mL of methanol, stir, add 7.7mL of 1mol / L hydrochloric acid, heat to 60℃ and reflux for 4h, rotary evaporate, add to distilled water, adjust pH to 8 with 5vt% sodium bicarbonate aqueous solution, extract with dichloromethane, collect the organic phase, rotary evaporate, and obtain the composite anti-aging agent.

[0032] This embodiment discloses a method for preparing a composite reinforcing agent, including the following steps: S1: 2.1 g of 2,4-dinitrotoluene and 1.9 g of benzaldehyde were added to a container, followed by 12 mL of N,N-dimethylformamide. Under nitrogen protection, 0.25 mL of diazabicyclopropionate was added and the reaction was carried out at -20 °C for 48 h. After the reaction was completed, the product was washed with saturated sodium chloride, extracted with ethyl acetate, dried, and concentrated to obtain product a. 1.92 g of product a, 3.63 g of 2-iodobenzoic acid, and 20 mL of ethyl acetate were added to a container and the mixture was heated to reflux at 82 °C for 12 h. After the reaction was completed, the product was filtered, washed with ethyl acetate, concentrated, and recrystallized with ethanol to obtain product b. S2: Add 1.88g of product b to a container containing 30mL of anhydrous acetonitrile, stir for 30min, then add 1.82mL of diazabicyclohexane and 4.22g of N-fluoro-N'-(chloromethyl)triethylenediaminebis(tetrafluoroborate) sequentially, stir at room temperature for 2h, after the reaction is complete, wash with saturated ammonium chloride solution, extract, dry, concentrate and purify to obtain product c; S3: Under a nitrogen atmosphere, 72.6 g of product c, 3.2 g of palladium on carbon and 200 mL of anhydrous ethanol were added to a container. After heating to 80 °C, 97.4 g of hydrazine hydrate was added. The reaction was carried out for 2 h, followed by filtration, cooling, washing, recrystallization, filtration, and vacuum drying to obtain product d. S4: Under nitrogen atmosphere, 3.48 g of product d was added to a container containing 53 mL of N,N-dimethylformamide. After stirring and mixing, 2.95 g of diphenylmethane-4,4'-diisocyanate was added. The mixture was heated to 80 °C and reacted for 12 h. After the reaction was completed, the product was added to distilled water, washed, and dried to obtain the composite reinforcing agent.

[0033] This embodiment discloses a composite acrylic resin, which is composed of the following components by weight: 55 parts methyl methacrylate, 25 parts styrene, 45 parts butyl acrylate, 26 parts ethyl acrylate, 5 parts glycidyl methacrylate, 0.2 parts azobisisobutyronitrile, 46 parts distilled water, 10 parts ethylene glycol, 1.2 parts composite anti-aging agent, 1.4 parts composite reinforcing agent, 0.5 parts dispersant, 0.5 parts defoamer, and 0.4 parts antioxidant.

[0034] This embodiment discloses a method for preparing a composite acrylic resin, including the following steps: Step 1: Add methyl methacrylate, styrene, butyl acrylate, ethyl acrylate and glycidyl methacrylate to a container filled with distilled water, then slowly add the dispersant and stir to mix to obtain a mixture. Step 2: Under nitrogen atmosphere, heat the mixture, then slowly add azobisisobutyronitrile (AIBN), stir and mix, keep the mixture at the temperature, cool, and then add ethylene glycol, composite anti-aging agent, composite reinforcing agent, defoamer and antioxidant in sequence. Continue stirring, adjust the pH to 7, cool, filter, and obtain composite acrylic resin.

[0035] Example 4: This example discloses a method for preparing a composite anti-aging agent, including the following steps: Q1: 3.5g of 7-hydroxy-4-methoxyisophenyl ketone, 4.33g of potassium carbonate and 83mL of methanol were added to a container in sequence. The mixture was heated to 82℃ and stirred for 30min. Then, 3.58g of 1,12-dibromododecane was added and the reaction was continued for 10h. After the reaction was completed, the mixture was rotary evaporated, distilled water was added, and a solid was precipitated. The solid was filtered and washed with distilled water and petroleum ether in sequence. After drying, the solid was added to a 60mL mixture of petroleum ether and ethyl acetate in a volume ratio of 3:1 and dispersed for 12h. After filtration, organic compound 1 was obtained. Q2: Add 1.53g of 1-tert-butoxycarbonyl-4-methylaminopiperidine, 5.27g of potassium carbonate, 0.22g of potassium iodide and 85mL of acetonitrile to a container, stir at room temperature for 30min, add 1.3g of organic compound 1, heat to 80℃ and react for 10h, filter, wash with dichloromethane, collect the filtrate and evaporate by rotary evaporation to purify, to obtain organic compound 2; Q3: Add 2.23g of organic compound 2 to a container containing 55mL of methanol, stir, add 5.8mL of 1mol / L hydrochloric acid, heat to 60℃ and reflux for 4h, rotary evaporate, add to distilled water, adjust pH to 8 with 5vt% sodium bicarbonate aqueous solution, extract with dichloromethane, collect the organic phase, rotary evaporate, and obtain the composite anti-aging agent.

[0036] This embodiment discloses a method for preparing a composite reinforcing agent, including the following steps: S1: 1.7 g of 2,4-dinitrotoluene and 1.3 g of benzaldehyde were added to a container, followed by 10.5 mL of N,N-dimethylformamide. Under nitrogen protection, 0.28 mL of diazabicyclopropionate was added and the reaction was carried out at -20 °C for 48 h. After the reaction was completed, the product was washed with saturated sodium chloride, extracted with ethyl acetate, dried, and concentrated to obtain product a. 1.63 g of product a, 3.32 g of 2-iodobenzoic acid, and 22 mL of ethyl acetate were added to a container and the mixture was heated to reflux at 82 °C for 12 h. After the reaction was completed, the product was filtered, washed with ethyl acetate, concentrated, and recrystallized with ethanol to obtain product b. S2: 1.36 g of product b was added to a container containing 32 mL of anhydrous acetonitrile. After stirring for 30 min, 1.55 mL of diazabicyclohexane and 4.06 g of N-fluoro-N'-(chloromethyl)triethylenediaminebis(tetrafluoroborate) were added sequentially. The mixture was stirred at room temperature for 2 h. After the reaction was completed, the product was washed with saturated ammonium chloride solution, extracted, dried, concentrated, and purified to obtain product c. S3: Under a nitrogen atmosphere, 70.6 g of product c, 2.4 g of palladium on carbon and 205 mL of anhydrous ethanol were added to a container, heated to 80 °C and then 92 g of hydrazine hydrate was added. The reaction was carried out for 2 h, then filtered, cooled, washed, recrystallized, filtered again and dried under vacuum to obtain product d. S4: Under nitrogen atmosphere, 3.21 g of product d was added to a container containing 47 mL of N,N-dimethylformamide. After stirring and mixing, 2.36 g of diphenylmethane-4,4'-diisocyanate was added, and the mixture was heated to 80 °C and reacted for 12 h. After the reaction was completed, the product was added to distilled water, washed, and dried to obtain the composite reinforcing agent.

[0037] This embodiment discloses a composite acrylic resin, which is composed of the following components by weight: 42 parts methyl methacrylate, 21 parts styrene, 35 parts butyl acrylate, 20 parts ethyl acrylate, 3 parts glycidyl methacrylate, 0.3 parts azobisisobutyronitrile, 32 parts distilled water, 11 parts ethylene glycol, 0.8 parts composite anti-aging agent, 1 part composite reinforcing agent, 0.6 parts dispersant, 0.2 parts defoamer, and 0.2 parts antioxidant.

[0038] This embodiment discloses a method for preparing a composite acrylic resin, including the following steps: Step 1: Add methyl methacrylate, styrene, butyl acrylate, ethyl acrylate and glycidyl methacrylate to a container filled with distilled water, then slowly add the dispersant and stir to mix to obtain a mixture. Step 2: Under nitrogen atmosphere, heat the mixture, then slowly add azobisisobutyronitrile (AIBN), stir and mix, keep the mixture at the temperature, cool, and then add ethylene glycol, composite anti-aging agent, composite reinforcing agent, defoamer and antioxidant in sequence. Continue stirring, adjust the pH to 7, cool, filter, and obtain composite acrylic resin.

[0039] Comparative Example 1: Compared with Example 1, Comparative Example 1 did not add a composite anti-aging agent during the preparation of the composite acrylic resin, and all other conditions remained unchanged.

[0040] Comparative Example 2: Compared with Example 1, Comparative Example 2 did not add a composite reinforcing agent during the preparation of the composite acrylic resin, and all other conditions remained unchanged.

[0041] Performance testing: The vehicle body metal panels were degreased, derusted, and phosphated to ensure a clean and dry surface. Then, the samples prepared according to Examples 1-4 and Comparative Examples 1-2 were sprayed onto the surface of the vehicle body metal panels and cured to obtain the test samples. The adhesion of the samples was tested according to GB / T9286-2021, the weather resistance according to GB / T 16422.2-2022, the hardness according to GB / T 6739-2022, and the chemical resistance according to GB / T 11547-2008. The test results are shown in Table 1.

[0042] Table 1

[0043]

[0044] When the adhesion grade is 0, the cut edges are completely smooth, and there is no peeling within the grid. When the adhesion grade is 1, a small amount of coating peels off at the cut intersections, but the affected cross-cut area is no more than 5%. When the adhesion grade is 2, the coating peels off at the cut intersections and / or along the cut edges, and the affected cross-cut area is greater than 5% but not more than 15%. When the adhesion grade is 3, the coating peels off partially or completely in large fragments along the cut edges, and / or partially or completely peels off at different locations on the grid, and the affected cross-cut area is greater than 15% but not more than 35%. When the adhesion grade is 4, the coating peels off in large fragments along the cut edges, and / or some squares peel off partially or completely, and the affected cross-cut area is greater than 35% but not more than 65%. When the adhesion grade is 5, the degree of peeling exceeds that of grade 4. As shown in Table 1, by using the methods of Examples 1-4, a composite acrylic resin with excellent adhesion, weather resistance, hardness, and chemical resistance can be prepared. A comparison of Comparative Example 1 and Examples 1-4 shows that the use of composite anti-aging agent can effectively improve the adhesion, weather resistance and chemical corrosion resistance of composite acrylic resin; a comparison of Comparative Example 2 and Examples 1-4 shows that the use of composite reinforcing agent can effectively improve the adhesion, weather resistance, hardness and chemical corrosion resistance of composite acrylic resin.

[0045] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0046] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A composite acrylic resin, characterized in that, It is composed of the following components by weight: 40-55 parts methyl methacrylate, 20-25 parts styrene, 32-45 parts butyl acrylate, 18-26 parts ethyl acrylate, 2-5 parts glycidyl methacrylate, 0.2-0.6 parts azobisisobutyronitrile, 30-46 parts distilled water, 10-14 parts ethylene glycol, 0.7-1.2 parts composite anti-aging agent, 0.9-1.4 parts composite reinforcing agent, 0.5-1 part dispersant, 0.1-0.5 parts defoamer, and 0.1-0.4 parts antioxidant; The chemical structural formula of the composite anti-aging agent is as follows: ； The chemical structural formula of the composite reinforcing agent is: 。 2. The composite acrylic resin according to claim 1, characterized in that, The preparation method of the composite anti-aging agent, Includes the following steps: Q1: 7-hydroxy-4-methoxyisophenyl ketone, potassium carbonate and methanol were added to a container in sequence. After heating and stirring, 1,12-dibromododecane was added to continue the reaction. After the reaction was completed, the mixture was rotary evaporated, distilled water was added, and a solid was precipitated. The solid was filtered, washed, dried, dispersed, and filtered again to obtain organic compound 1. Q2: Add 1-tert-butoxycarbonyl-4-methylaminopiperidine, potassium carbonate, potassium iodide and acetonitrile to a container, stir at room temperature, add organic compound 1, heat to react, filter, wash, collect the filtrate and then rotary evaporate to purify, to obtain organic compound 2. Q3: Add organic compound 2 to a container containing methanol, stir, add hydrochloric acid, heat to reflux and react, rotary evaporate, add to distilled water, adjust pH, extract, collect organic phase, rotary evaporate, and obtain composite anti-aging agent.

3. The composite acrylic resin according to claim 2, characterized in that, In Q1, the ratio of 7-hydroxy-4-methoxyisophenyl ketone, potassium carbonate, methanol, and 1,12-dibromododecane is (3.2-4.3) g : (4.11-5.28) g : (80-95) mL : (3.54-3.68) g; in Q2, the ratio of 1-tert-butylcarbonyl-4-methylaminopiperidine, potassium carbonate, potassium iodide, acetonitrile, and organic compound 1 is (1.42-1.88) g : (5.11-5.65) g : (0.21-0.28) g : (80-100) mL : (1.2-1.8) g.

4. The composite acrylic resin according to claim 2, characterized in that, In Q3, the ratio of organic compound 2, methanol and hydrochloric acid is (2.12-2.47) g : (50-76) mL : (5.2-7.7) mL.

5. The composite acrylic resin according to claim 1, characterized in that, The preparation method of the composite reinforcing agent includes the following steps: S1: 2,4-Dinitrotoluene and benzaldehyde were added to a container, followed by N,N-dimethylformamide. Under nitrogen protection, diazabicyclopropionate was added to react. After the reaction was complete, the mixture was washed, extracted, dried, and concentrated to obtain product a. Product a, 2-iodobenzoic acid, and ethyl acetate were added to a container and heated under reflux. After the reaction was complete, the mixture was filtered, washed, concentrated, and recrystallized to obtain product b. S2: Add product b to a container containing anhydrous acetonitrile, stir, then add diazabicyclohexane and N-fluoro-N'-(chloromethyl)triethylenediaminebis(tetrafluoroborate) in sequence, stir the reaction at room temperature, and after the reaction is complete, wash, extract, dry, concentrate, and purify to obtain product c; S3: Under a nitrogen atmosphere, product c, palladium on carbon and anhydrous ethanol were added to a container, heated and then hydrazine hydrate was added. The mixture was reacted, then filtered, cooled, washed, recrystallized, filtered again, and dried under vacuum to obtain product d. S4: Under nitrogen atmosphere, product d is added to a container containing N,N-dimethylformamide, stirred and mixed, then diphenylmethane-4,4'-diisocyanate is added, and the mixture is heated to react. After the reaction is complete, the product is added to distilled water, washed, and dried to obtain the composite reinforcing agent.

6. The composite acrylic resin according to claim 5, characterized in that, In S1, the ratio of 2,4-dinitrotoluene, benzaldehyde, N,N-dimethylformamide and diazabicyclobenzyl is (1.5-2.1) g : (1.2-1.9) g : (10-12) mL : (0.25-0.35) mL; the ratio of product a, 2-iodobenzoic acid and ethyl acetate is (1.5-1.92) g : (3.21-3.63) g : (20-30) mL.

7. The composite acrylic resin according to claim 5, characterized in that, In S2, the ratio of product b, anhydrous acetonitrile, diazabicyclohexane, and N-fluoro-N'-(chloromethyl)triethylenediamine bis(tetrafluoroborate) is (1.2-1.88) g : (30-45) mL : (1.5-1.82) mL : (3.98-4.22) g; in S3, the ratio of product c, palladium on carbon, anhydrous ethanol, and hydrazine hydrate is (70-72.6) g : (2-3.2) g : (200-220) mL : (90-97.4) g.

8. The composite acrylic resin according to claim 5, characterized in that, In S3, the ratio of product d, N,N-dimethylformamide and diphenylmethane-4,4'-diisocyanate is (3.12-3.48) g : (45-53) mL : (2.28-2.95) g.

9. The method for preparing the composite acrylic resin according to any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Add methyl methacrylate, styrene, butyl acrylate, ethyl acrylate and glycidyl methacrylate to a container filled with distilled water, then slowly add the dispersant and stir to mix to obtain a mixture. Step 2: Under nitrogen atmosphere, heat the mixture, then slowly add azobisisobutyronitrile (AIBN), stir and mix, keep the mixture at the desired temperature, cool, and then add ethylene glycol, composite anti-aging agent, composite reinforcing agent, defoamer and antioxidant in sequence. Continue stirring, adjust the pH, cool, and filter to obtain composite acrylic resin.

10. The application of composite acrylic resin, characterized in that, The composite acrylic resin according to any one of claims 1-8 is applied to automotive paint.

Images