Automobile refinishing paint and preparation method thereof

Abstract

The invention discloses an automobile refinishing paint and a preparation method thereof, belongs to the technical field of coatings, and aims to solve the technical problem that the drying performance and the wear resistance of the automobile refinishing paint in the prior art need to be improved. The preparation method of the automobile refinishing paint comprises the following steps: mixing the water, the modified epoxy resin, the flatting agent, the quartz powder, the nano calcium carbonate, the ultraviolet absorbent and the defoaming agent, stirring, adding the curing agent, and uniformly mixing to obtain the automobile refinishing paint. The automobile refinishing paint prepared by the preparation method disclosed by the invention has good drying performance and wear resistance, also has excellent adhesive force and is capable of preventing cracking, and the service life of the automobile refinishing paint is prolonged due to good weather resistance of the automobile refinishing paint.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of paint technology, in particular to a kind of automobile repair paint and preparation method thereof. BACKGROUND

[0002] In modern transportation system, car has become an important tool for people to travel indispensable. However, in the process of daily use, car body is inevitably subjected to various damages such as scratches, bumps and so on. These seemingly insignificant problems, actually have far-reaching influence, not only destroy the original beauty of car, but also speed up the corrosion process of car body due to the damage of surface protective layer, and thus threaten the overall performance and service life of car. To effectively deal with this common problem, automobile repair paint emerges as the times require, and plays a vital role in the field of automobile repair. It can effectively repair the damage on the surface of car body and restore the original beauty of car. At the same time, high-quality repair paint can also form a protective layer to prevent further damage to car body caused by external environment and prolong the service life of car. Automobile repair paint needs to withstand the test of daily use, such as friction, ultraviolet radiation and various weather conditions. In addition, through scientific proportioning and strict process control, high-quality repair paint not only can ensure the appearance repair effect, provide long-term protection and meet the dual demands of car owners on the appearance and practicability of vehicle, but also takes into account the impact on the environment, so as to achieve the balance between performance and sustainability.

[0003] Chinese patent CN101787098B discloses a preparation method of acrylate hybrid emulsion and its application. The acrylate hybrid emulsion is synthesized by seed emulsion polymerization process combined with instant neutralization and polar monomer segmented dropping process. The acrylate hybrid emulsion prepared by the invention has excellent water resistance, solvent resistance, high hardness and wear resistance when used to prepare water-based two-component polyurethane coating. The specification discloses that the surface drying time of the water-based two-component polyurethane coating is 1h, and the drying time needs to be improved. In addition, automobile repair paint needs to have good wear resistance. SUMMARY

[0004] The present application aims to provide an automobile repair paint and a preparation method thereof, which can solve the technical problem that the drying performance of the automobile repair paint in the prior art needs to be improved, and at the same time has good wear resistance.

[0005] In order to achieve the above-mentioned purpose, the present application provides a preparation method of automobile repair paint, which comprises the following steps:

[0006] Mixing water, modified epoxy resin, leveling agent, quartz powder, nano calcium carbonate, ultraviolet absorber and defoaming agent, stirring, adding curing agent, mixing uniformly to obtain automobile repair paint;

[0007] Preparation of the modified epoxy resin comprises the following steps:

[0008] Step (1) : mixing deionized water, titanium dioxide and 3-aminopropyl triethoxysilane uniformly, heating and reacting, after the reaction is completed, filtering, washing and drying to obtain amino-modified titanium dioxide;

[0009] Step (2) : mixing epoxy resin, amino-modified titanium dioxide and hydrochloric acid solution, heating and reacting, after the reaction is completed, adding acetone, filtering and washing to obtain titanium dioxide grafted epoxy resin;

[0010] Step (3) : mixing tetrahydrofuran, methacrylic acid, titanium dioxide grafted epoxy resin, 4-dimethylaminopyridine and dicyclohexyl carbodiimide uniformly, heating and reacting, after the reaction is completed, filtering and distilling under reduced pressure to obtain methacrylic acid grafted epoxy resin;

[0011] Step (4) : mixing isooctyl methacrylate, trifluoroethyl methacrylate, butyl methacrylate, styrene, emulsifier and water uniformly, adding methacrylic acid grafted epoxy resin, continuing to stir, adding initiator, heating and reacting, after the reaction is completed, adjusting pH, stripping under the conditions of reduced pressure and nitrogen inlet, cooling to room temperature to obtain modified epoxy resin.

[0012] Preferably, the mass ratio of water, modified epoxy resin, leveling agent, quartz powder, nano calcium carbonate, ultraviolet absorber, defoaming agent and curing agent is (20-40) : (60-80) : (1-2) : (4-6) : (5-9) : (1-3) : (0.3-0.7) : (15-25).

[0013] Preferably, in the step (1), the mass ratio of deionized water, titanium dioxide and 3-aminopropyl triethoxysilane is (1000-1600) : (60-80) : (45-65).

[0014] Preferably, in the step (1), the reaction temperature is 60-80℃ and the reaction time is 2-4h.

[0015] Preferably, in the step (2), the mass ratio of epoxy resin, amino-modified titanium dioxide, hydrochloric acid solution and acetone is (1000-1600) : (80-100) : (2000-3600) : (5000-7000), and the concentration of the hydrochloric acid solution is 0.01 mol / L.

[0016] Preferably, in the step (2), the reaction temperature is 70-90℃ and the reaction time is 1.5-2.5h.

[0017] Preferably, in the step (3), the mass ratio of tetrahydrofuran, methacrylic acid, titanium dioxide grafted epoxy resin, 4-dimethylamino pyridine and dicyclohexyl carbodiimide is (3000-5000):(40-60):(1200-2000):(6-10):(90-120).

[0018] Preferably, in the step (3), the reaction temperature is 30-40℃, and the reaction time is 2-4h.

[0019] Preferably, in the step (4), the mass ratio of isooctyl methacrylate, trifluoroethyl methacrylate, butyl methacrylate, styrene, emulsifier, water, methacrylic acid grafted epoxy resin and initiator is (45-55):(9-11):(28-32):(19-21):(3.5-4.5):(240-260):(35-45):(1.5-2.5).

[0020] Preferably, in the step (4), the reaction temperature is 50-70℃, and the reaction time is 3-5h.

[0021] Preferably, the curing agent is a fatty amine curing agent.

[0022] Preferably, the emulsifier is a gemini quaternary ammonium salt.

[0023] Preferably, the leveling agent is any one of Tego-450 and BYK-333.

[0024] Preferably, the defoaming agent is BYK-024.

[0025] Preferably, the initiator is V50.

[0026] Preferably, the process parameters of the stripping under the conditions of reduced pressure and nitrogen inletting are as follows: 0.08-0.09MPa, nitrogen inletting stripping for 1-2h, and nitrogen flow rate is 0.5-1L / min.

[0027] An automobile repair paint prepared by the preparation method of the automobile repair paint.

[0028] Compared with the prior art, the automobile repair paint has the following beneficial effects:

[0029] 1. The titanium dioxide used in the present application is an inorganic material that can effectively absorb and scatter ultraviolet light under ultraviolet irradiation. The principle of its ultraviolet resistance mainly includes two aspects: one is to absorb ultraviolet light and convert it into heat energy, and the other is to enhance ultraviolet resistance by scattering ultraviolet light. At the same time, due to the small size of titanium dioxide, modification of titanium dioxide can effectively avoid the agglomeration of titanium dioxide, and can be uniformly dispersed to maintain its functional stability. And adding it to the matrix will increase the wear resistance and improve the performance of the matrix. The amino-modified titanium dioxide is covalently bonded with the epoxy resin, so that the inorganic nanoparticles of titanium dioxide are uniformly dispersed in the resin matrix.

[0030] 2. The present application uses ultraviolet absorber and titanium dioxide to form an anti-ultraviolet barrier, reduces the damage of ultraviolet light, and is beneficial to durability. The introduction of trifluoroethyl methacrylate gives the paint film a "low surface energy protective layer". The strong electronegativity of the fluorine atom contained in it makes the paint film surface form a dense hydrophobic and oleophobic layer, reducing the adhesion and penetration of water, and the C-F bond energy contained in it is large, and the energy of ultraviolet light is difficult to break the C-F bond, which is beneficial to the service life of the paint film. In the present application, the carboxyl group in the methacrylic acid reacts with the hydroxyl group in the grafted epoxy resin to obtain a methacrylic acid grafted epoxy resin. The methacrylic acid grafted epoxy resin contains unsaturated carbon-carbon double bonds, which can react with isooctyl methacrylate, trifluoroethyl methacrylate, butyl methacrylate and styrene under the action of initiator to obtain modified epoxy resin. The introduction of methacrylic acid increases the polarity of the epoxy resin, and the free radical reaction of the acrylic ester substance adjusts the flexibility, so that the paint film is not easy to peel off due to internal stress when cold and hot are alternated, and the adhesion is further improved. The benzene ring in styrene has a certain rigidity, which can increase the hardness of the paint film and improve the wear resistance. The modified epoxy resin rapidly forms a network cross-linked structure under the action of the curing agent, and the higher the cross-linking degree, the more conducive to improving the weather resistance.

[0031] 3. The quartz powder in the present application is a high-hardness inorganic filler that is uniformly dispersed in the paint film to increase the wear resistance and can directly resist the cutting effect of external friction on the surface of the paint film; nano calcium carbonate fills the pores to further improve the density of the paint film. The long-chain alkyl of isooctyl methacrylate and butyl methacrylate gives the matrix a certain flexibility, so that the paint film can absorb energy through slight deformation when impacted and rubbed, avoiding rigid fracture; and the styrene unit ensures the overall hardness of the paint film, preventing excessive deformation from causing increased wear. This structure makes the paint film neither easy to be worn out nor easy to fail due to brittle cracking in repeated friction. In addition, the epoxy resin has good adhesion and water solubility, significantly improving the interfacial bonding force with the substrate. High adhesion ensures that the wear-resistant particles and the resin, as well as the paint film and the substrate, will not delaminate due to frictional stress, and the high-density cross-linked structure formed by rapid drying avoids the pore defects in the paint film, further improving the wear resistance.

[0032] 4. The automobile repair paint provided by the present application has excellent adhesion and weather resistance, and can effectively cope with various harsh environmental conditions. The preparation process is not only simple and efficient, but also ensures high gloss and good leveling of the paint film. In addition, the repair paint further improves the hardness and flexibility of the paint film by optimizing the proportion of each component in the formula, so that it has a wider application prospect in the field of automobile repair. DETAILED DESCRIPTION

[0033] The technical solutions of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0034] Embodiment 1

[0035] The present embodiment provides a preparation method of an automobile repair paint, comprising the following steps:

[0036] Mix water, modified epoxy resin, BYK-333, quartz powder, nano calcium carbonate, ultraviolet absorber and BYK-024, stir, add curing agent, mix uniformly, to obtain an automobile repair paint;

[0037] Among them, the mass ratio of water, modified epoxy resin, BYK-333, quartz powder, nano calcium carbonate, ultraviolet absorber, BYK-024 and curing agent is 20:60:1:4:5:1:0.3:15;

[0038] Among them, the preparation of modified epoxy resin comprises the following steps:

[0039] Step (1) Mix deionized water, titanium dioxide and 3-aminopropyl triethoxysilane according to the mass ratio of 1000:60:45, react at 60℃ for 4h, after the reaction is completed, filter, wash with deionized water for 3 times, dry at 80℃ for 5h, to obtain amino-modified titanium dioxide;

[0040] Step (2) Mix epoxy resin, amino-modified titanium dioxide and 0.01mol / L hydrochloric acid solution, react at 70℃ for 2.5h, after the reaction is completed, add acetone, filter, wash with deionized water for 3 times, to obtain titanium dioxide grafted epoxy resin;

[0041] Among them, the mass ratio of epoxy resin, amino-modified titanium dioxide, hydrochloric acid solution and acetone is 1000:80:2000:5000;

[0042] Step (3) tetrahydrofuran, methacrylic acid, titanium dioxide grafted epoxy resin, 4-dimethylamino pyridine and dicyclohexyl carbodiimide were mixed in a mass ratio of 3000:40:1200:6:90, heated, reacted at 30℃ for 4h, filtered, distilled under reduced pressure, and methacrylic acid grafted epoxy resin was obtained;

[0043] Step (4) isooctyl methacrylate, trifluoroethyl methacrylate, butyl methacrylate, styrene, emulsifier and water were mixed and stirred uniformly, then the methacrylic acid grafted epoxy resin was added, and the stirring was continued, then the initiator V50 was added, heated to 50℃ and reacted for 5h, then the reaction was stopped, the pH was adjusted to 8, 0.08MPa, nitrogen was introduced at a flow rate of 0.5L / min, and stripping was carried out for 2h, and then the temperature was cooled to room temperature to obtain the modified epoxy resin;

[0044] The mass ratio of isooctyl methacrylate, trifluoroethyl methacrylate, butyl methacrylate, styrene, emulsifier, water, methacrylic acid grafted epoxy resin and V50 is 45:9:28:19:3.5:240:35:1.5.

[0045] Example 2

[0046] The present embodiment provides a preparation method of an automobile repair paint, which comprises the following steps:

[0047] The water, modified epoxy resin, BYK-333, quartz powder, nano calcium carbonate, ultraviolet absorber and BYK-024 were mixed and stirred, then the curing agent was added and mixed uniformly to obtain the automobile repair paint.

[0048] The mass ratio of water, modified epoxy resin, BYK-333, quartz powder, nano calcium carbonate, ultraviolet absorber, BYK-024 and curing agent is 25:65:1.2:4.5:6:1.5:0.4:17.

[0049] The preparation of the modified epoxy resin comprises the following steps:

[0050] Step (1) deionized water, titanium dioxide and 3-aminopropyl triethoxysilane were mixed in a mass ratio of 1150:65:50 and uniformly mixed, and reacted at 65℃ for 3.5h, then after the reaction was completed, the filtration was performed, deionized water was washed for 3 times, and then the drying was performed at 85℃ for 4.5h to obtain the amino-modified titanium dioxide;

[0051] Step (2) the epoxy resin, the amino-modified titanium dioxide and 0.01mol / L hydrochloric acid aqueous solution were mixed, and reacted at 75℃ for 2.2h, then after the reaction was completed, the acetone was added, the filtration was performed, and deionized water was washed for 3 times to obtain the titanium dioxide grafted epoxy resin;

[0052] The mass ratio of the epoxy resin, the amino-modified titanium dioxide, the hydrochloric acid aqueous solution, and the acetone is 1150:85:2400:5500;

[0053] Step (3) tetrahydrofuran, methacrylic acid, titanium dioxide grafted epoxy resin, 4-dimethylaminopyridine and dicyclohexyl carbodiimide are mixed in a mass ratio of 3500:45:1400:7:97, heated, reacted at a temperature of 32℃ for 3.5h, filtered after the reaction is completed, and distilled under reduced pressure to obtain the methacrylic acid grafted epoxy resin;

[0054] Step (4) isooctyl methacrylate, trifluoroethyl methacrylate, butyl methacrylate, styrene, an emulsifier, and water are mixed and stirred uniformly, the methacrylic acid grafted epoxy resin is added, stirring is continued, the initiator V50 is added, heated to 55℃ and reacted for 4.5h, the reaction is completed, the pH is adjusted to 8, nitrogen is introduced at a flow rate of 0.6L / min under 0.08MPa, and stripping is performed for 1.8h, and the modified epoxy resin is obtained after cooling to room temperature;

[0055] The mass ratio of the isooctyl methacrylate, the trifluoroethyl methacrylate, the butyl methacrylate, the styrene, the emulsifier, the water, the methacrylic acid grafted epoxy resin, and the V50 is 47:9.5:29:19.5:3.7:245:37:1.7.

[0056] Example 3

[0057] The embodiment provides a preparation method of an automobile repair paint, and the method comprises the following steps:

[0058] The water, the modified epoxy resin, the BYK-333, the quartz powder, the nano calcium carbonate, the ultraviolet absorber, and the BYK-024 are mixed and stirred, the curing agent is added, and the mixture is uniformly mixed to obtain the automobile repair paint.

[0059] The mass ratio of the water, the modified epoxy resin, the BYK-333, the quartz powder, the nano calcium carbonate, the ultraviolet absorber, the BYK-024, and the curing agent is 30:70:1.5:5:7:2:0.5:20.

[0060] The preparation of the modified epoxy resin comprises the following steps:

[0061] Step (1) deionized water, titanium dioxide, and 3-aminopropyl triethoxysilane are uniformly mixed in a mass ratio of 1300:70:55, reacted at a temperature of 70℃ for 3h, after the reaction is completed, filtered, washed with deionized water for 3 times, and dried at a temperature of 90℃ for 4h to obtain the amino-modified titanium dioxide.

[0062] Step (2) mixed epoxy resin, amino-modified titanium dioxide and 0.01 mol / L hydrochloric acid aqueous solution, reacted for 2h at 80℃, after the reaction, added acetone, filtered, washed with deionized water for 3 times, to obtain titanium dioxide grafted epoxy resin;

[0063] The mass ratio of the epoxy resin, the amino-modified titanium dioxide, the hydrochloric acid aqueous solution and the acetone is 1300:90:2800:6000.

[0064] Step (3) mixed tetrahydrofuran, methacrylic acid, titanium dioxide grafted epoxy resin, 4-dimethylaminopyridine and dicyclohexyl carbodiimide according to the mass ratio of 4000:50:1600:8:105, heated, reacted for 3h at 35℃, after the reaction, filtered, distilled under reduced pressure, to obtain methacrylic acid grafted epoxy resin;

[0065] Step (4) mixed isooctyl methacrylate, trifluoroethyl methacrylate, butyl methacrylate, styrene, emulsifier and water, stirred uniformly, added methacrylic acid grafted epoxy resin, continued to stir, added initiator V50, heated to 60℃ and reacted for 4h, after the reaction, adjusted pH to 8, 0.08MPa, nitrogen was introduced according to the flow rate of 0.7L / min, and stripping was carried out for 1.5h, cooled to room temperature, to obtain modified epoxy resin;

[0066] The mass ratio of the isooctyl methacrylate, the trifluoroethyl methacrylate, the butyl methacrylate, the styrene, the emulsifier, the water, the methacrylic acid grafted epoxy resin and the V50 is 50:10:30:20:4:250:40:2.

[0067] Example 4

[0068] The embodiment provides a preparation method of automobile repair paint, comprising the following steps:

[0069] Mixed water, modified epoxy resin, BYK-333, quartz powder, nano calcium carbonate, ultraviolet absorber and BYK-024, stirred, added curing agent, mixed uniformly, to obtain automobile repair paint.

[0070] The mass ratio of the water, the modified epoxy resin, the BYK-333, the quartz powder, the nano calcium carbonate, the ultraviolet absorber, the BYK-024 and the curing agent is 35:75:1.8:5.5:8:2.5:0.6:22.

[0071] The preparation of the modified epoxy resin comprises the following steps:

[0072] Step (1) Deionized water, titanium dioxide and 3-aminopropyl triethoxysilane were mixed uniformly according to a mass ratio of 1450:75:60, and reacted at a temperature of 75 DEG C for 2.5 hours. After the reaction was completed, the mixture was filtered, washed with deionized water for 3 times, and dried at a temperature of 95 DEG C for 3.5 hours to obtain the amino-modified titanium dioxide;

[0073] Step (2) The epoxy resin, the amino-modified titanium dioxide and 0.01 mol / L hydrochloric acid solution were mixed, and reacted at a temperature of 85 DEG C for 1.7 hours. After the reaction was completed, acetone was added, the mixture was filtered, and washed with deionized water for 3 times to obtain the titanium dioxide grafted epoxy resin;

[0074] The mass ratio of the epoxy resin, the amino-modified titanium dioxide, the hydrochloric acid solution and the acetone was 1450:95:3200:6500.

[0075] Step (3) Tetrahydrofuran, methacrylic acid, the titanium dioxide grafted epoxy resin, 4-dimethylaminopyridine and dicyclohexyl carbodiimide were mixed according to a mass ratio of 4500:55:1800:9:112, heated, and reacted at a temperature of 37 DEG C for 2.5 hours. After the reaction was completed, the mixture was filtered and distilled under reduced pressure to obtain the methacrylic acid grafted epoxy resin;

[0076] Step (4) Isooctyl methacrylate, trifluoroethyl methacrylate, butyl methacrylate, styrene, an emulsifier and water were mixed and stirred uniformly. The methacrylic acid grafted epoxy resin was added, and the mixture was continuously stirred. The initiator V50 was added, heated to 65 DEG C and reacted for 3.5 hours. After the reaction was completed, the pH was adjusted to 8, nitrogen was introduced at a flow rate of 0.8 L / min under a pressure of 0.09 MPa, and the mixture was stripped for 1.2 hours. After the mixture was cooled to room temperature, the modified epoxy resin was obtained.

[0077] The mass ratio of the isooctyl methacrylate, the trifluoroethyl methacrylate, the butyl methacrylate, the styrene, the emulsifier, the water, the methacrylic acid grafted epoxy resin and the V50 was 52:10.5:31:20.5:4.2:255:42:2.2.

[0078] Example 5

[0079] The present embodiment provides a preparation method of an automobile repair paint, which comprises the following steps:

[0080] The water, the modified epoxy resin, BYK-333, quartz powder, nano calcium carbonate, an ultraviolet absorber and BYK-024 were mixed and stirred. The curing agent was added and mixed uniformly to obtain the automobile repair paint.

[0081] The mass ratio of water, modified epoxy resin, BYK-333, quartz powder, nano calcium carbonate, ultraviolet absorber, BYK-024 and curing agent is 40:80:2:6:9:3:0.7:25;

[0082] The preparation of the modified epoxy resin comprises the following steps:

[0083] Step (1) : Deionized water, titanium dioxide and 3-aminopropyl triethoxysilane are mixed uniformly according to a mass ratio of 1600:80:65, and reacted at a temperature of 80°C for 2h. After the reaction is completed, filtration is performed, and the product is washed with deionized water for 3 times, and then dried at a temperature of 100°C for 3h to obtain amino-modified titanium dioxide;

[0084] Step (2) : Epoxy resin, amino-modified titanium dioxide and 0.01mol / L hydrochloric acid solution are mixed, and reacted at a temperature of 90°C for 1.5h. After the reaction is completed, acetone is added, filtration is performed, and the product is washed with deionized water for 3 times to obtain titanium dioxide grafted epoxy resin;

[0085] The mass ratio of epoxy resin, amino-modified titanium dioxide, hydrochloric acid solution and acetone is 1600:100:3600:7000;

[0086] Step (3) : Tetrahydrofuran, methacrylic acid, titanium dioxide grafted epoxy resin, 4-dimethylaminopyridine and dicyclohexyl carbodiimide are mixed according to a mass ratio of 5000:60:2000:10:120, heated, and reacted at a temperature of 40°C for 2h. After the reaction is completed, filtration is performed, and the product is distilled under reduced pressure to obtain methacrylic acid grafted epoxy resin;

[0087] Step (4) : Isooctyl methacrylate, trifluoroethyl methacrylate, butyl methacrylate, styrene, emulsifier and water are mixed and stirred uniformly, and then the methacrylic acid grafted epoxy resin is added and continuously stirred. The initiator V50 is added, heated to 70°C and reacted for 3h. After the reaction is completed, the pH is adjusted to 8, nitrogen is introduced at a flow rate of 1L / min under a pressure of 0.09MPa, and stripping is performed for 1h. After cooling to room temperature, the modified epoxy resin is obtained;

[0088] The mass ratio of isooctyl methacrylate, trifluoroethyl methacrylate, butyl methacrylate, styrene, emulsifier, water, methacrylic acid grafted epoxy resin and V50 is 55:11:32:21:4.5:260:45:2.5.

[0089] Comparative Example 1

[0090] The difference between this comparative example and Example 1 is that the trifluoroethyl methacrylate in step (4) is replaced by water in equal amount.

[0091] Comparative Example 2

[0092] The difference between this comparative example and Example 1 is that step (4) is omitted, and the modified epoxy resin is replaced with an equal mass of methacrylic acid grafted epoxy resin.

[0093] Comparative Example 3

[0094] The difference between this comparative example and Example 1 is that steps (3) and (4) are omitted, and the modified epoxy resin is replaced with an equal mass of titanium dioxide-grafted epoxy resin.

[0095] Comparative Example 4

[0096] This comparative example is the weather-resistant automotive repair clear coat disclosed in Example 4 of Chinese patent application CN109161324B.

[0097] Comparative Example 5

[0098] This comparative example is the ultra-fast drying water-based clear coat for automotive repair disclosed in Example 3 of Chinese patent application CN114525075B.

[0099] In the embodiments and comparative examples 1-3 of this invention, the epoxy resin is Phoenix brand E-44 bisphenol A type epoxy resin, sourced from Shenyang Xinmaofa Fine Chemical Raw Materials Co., Ltd.; the curing agent is... 2771 fatty amine, from Shandong Tunan New Materials Co., Ltd.; emulsifier 31524, a Gemini quaternary ammonium salt, from Zhengzhou Yihe Fine Chemicals Co., Ltd.; initiator V50 and acetone, both from Sinopharm Chemical Reagent Co., Ltd.; UV absorber, UV-1130, from Dongguan Kangjin New Materials Technology Co., Ltd.; BYK-024, from Guangzhou Yitong Polymer Materials Co., Ltd.; BYK-333, from BAK (Germany); titanium dioxide, JR05, with an average particle size of 5nm, from Xuancheng Jingrui New Materials Co., Ltd.; quartz powder, from Wuhan Jiyesheng Chemical Co., Ltd.; nano calcium carbonate, from Ningbo Luofei Nanotechnology Co., Ltd.; and all other products are commercially available.

[0100] Performance testing:

[0101] The automotive refinish paints in Examples 1-5 and Comparative Examples 1-5 were tested accordingly, and the test results are shown below:

[0102] (1) Drying performance test: The drying time was tested in accordance with the relevant standard of "HG / T 5061-2016 Coatings for Automotive Repair". The test was repeated 3 times and the average value was recorded. The specific test results are shown in Table 1.

[0103] (2) Hardness test: Refer to "GBT 6739-2006 Pencil method for determining the hardness of paint film", the test results are shown in Table 1;

[0104] (3) Abrasion resistance test: the test standard refers to GB / T 1768-89, the machine is M-I type paint film abrasion tester, the weight of the weight is 500 g, the test rotation is 1000 rotations, repeated 3 times, and the average value is recorded. The test results are shown in Table 1.

[0105] (4) Adhesion test: determined according to the national standard GB / T 9286-1998;

[0106] (5) DOI value, gloss test: the DOI value and gloss of the automobile repair paint in Examples 1-5 and Comparative Examples 1-5 were tested according to the relevant standards of HG / T 5061-2016 Automotive Repair Coatings. The specific test results are shown in Table 1.

[0107] (6) Weather resistance test: the paint film of the automobile repair paint in Examples 1-5 and Comparative Examples 1-5 was tested, and the paint film was subjected to artificial accelerated aging under ultraviolet light for 5000 h. The light loss rate was recorded. The specific test results are shown in Table 1.

[0108] Table 1

[0109]

[0110] As can be seen from the above results, the automobile repair paint in Examples 1-5 has good drying performance, adhesion and abrasion resistance. The automobile repair paint prepared by the present application has good paint film appearance and good weather resistance, which is beneficial to prolong the service life. Compared with Example 1, Comparative Example 1 lacks the introduction of methyl acrylate trifluoroethyl ester, and the weather resistance is reduced. This is mainly because the C-F bond in methyl acrylate trifluoroethyl ester has a large bond energy and is destroyed at a high energy. Compared with Example 1, Comparative Example 2 lacks the introduction of acrylate, which affects the drying performance and further reduces the weather resistance. Compared with Example 1, Comparative Example 3 uses titanium dioxide grafted epoxy resin instead of modified epoxy resin, which reduces the weather resistance and drying performance, but enhances the adhesion. This is mainly because the content of epoxy resin is higher than that of Example 1, and the addition of styrene is lacking, which reduces the hardness and abrasion resistance.

[0111] The above content is only an example and description of the structure of the present application. Those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace, as long as they do not deviate from the structure of the invention or exceed the scope defined by the present claims, which should belong to the protection scope of the present application.

[0112] In the description of the specification, reference to "one embodiment", "an example", "a specific example" or the like means that a particular feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. The appearances of the phrases "in one embodiment", "an example", "a specific example" or the like in various places in the specification are not necessarily referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0113] The preferred embodiments of the application disclosed above are only to help explain the application. The preferred embodiments do not describe all the details of the application and limit the application to the specific embodiments. Obviously, many modifications and variations can be made in light of the contents of the specification. The specification selects and specifically describes these embodiments in order to better explain the principles and practical application of the application, so that those skilled in the art can well understand and utilize the application. The application is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing an automotive repair paint, characterized in that, Includes the following steps: Mix water, modified epoxy resin, leveling agent, quartz powder, nano calcium carbonate, UV absorber and defoamer, stir, add curing agent, mix evenly to obtain automotive repair paint; The preparation of modified epoxy resin includes the following steps: Step (1) Mix deionized water, titanium dioxide and 3-aminopropyltriethoxysilane evenly, heat to react, filter, wash and dry to obtain amino-modified titanium dioxide. Step (2) Mix epoxy resin, amino-modified titanium dioxide and hydrochloric acid aqueous solution, heat to react, after the reaction is completed, add acetone, filter, wash, and obtain titanium dioxide grafted epoxy resin. Step (3) Tetrahydrofuran, methacrylic acid, titanium dioxide-grafted epoxy resin, 4-dimethylaminopyridine and dicyclohexylcarbodiimide are mixed evenly, heated to react, filtered and distilled under reduced pressure to obtain methacrylic acid-grafted epoxy resin. Step (4) Mix isooctyl methacrylate, trifluoroethyl methacrylate, butyl methacrylate, styrene, emulsifier and water, stir evenly, add methacrylic acid grafted epoxy resin, continue stirring, add initiator, heat to react, after the reaction is completed, adjust pH, strip under reduced pressure and nitrogen gas, cool to room temperature to obtain modified epoxy resin.

2. The method for preparing an automotive repair paint according to claim 1, characterized in that, The mass ratio of water, modified epoxy resin, leveling agent, quartz powder, nano calcium carbonate, ultraviolet absorber, defoamer and curing agent is (20-40):(60-80):(1-2):(4-6):(5-9):(1-3):(0.3-0.7):(15-25).

3. The method for preparing an automotive repair paint according to claim 1, characterized in that, In step (1), the mass ratio of deionized water, titanium dioxide and 3-aminopropyltriethoxysilane is (1000-1600):(60-80):(45-65).

4. The method for preparing an automotive repair paint according to claim 1, characterized in that, In step (1), the reaction temperature is 60-80℃ and the reaction time is 2-4h.

5. The method for preparing an automotive repair paint according to claim 1, characterized in that, In step (2), the mass ratio of epoxy resin, amino-modified titanium dioxide, hydrochloric acid aqueous solution and acetone is (1000-1600):(80-100):(2000-3600):(5000-7000), and the concentration of hydrochloric acid aqueous solution is 0.01 mol / L.

6. The method for preparing an automotive repair paint according to claim 1, characterized in that, In step (2), the reaction temperature is 70-90℃ and the reaction time is 1.5-2.5h.

7. The method for preparing an automotive repair paint according to claim 1, characterized in that, In step (3), the mass ratio of tetrahydrofuran, methacrylic acid, titanium dioxide-grafted epoxy resin, 4-dimethylaminopyridine and dicyclohexylcarbodiimide is (3000-5000):(40-60):(1200-2000):(6-10):(90-120).

8. The method for preparing an automotive repair paint according to claim 1, characterized in that, In step (3), the reaction temperature is 30-40℃ and the reaction time is 2-4h.

9. The method for preparing an automotive repair paint according to claim 1, characterized in that, In step (4), the mass ratio of isooctyl methacrylate, trifluoroethyl methacrylate, butyl methacrylate, styrene, emulsifier, water, methacrylate-grafted epoxy resin and initiator is (45-55):(9-11):(28-32):(19-21):(3.5-4.5):(240-260):(35-45):(1.5-2.5).

10. The method for preparing an automotive repair paint according to claim 1, characterized in that, In step (4), the reaction temperature is 50-70℃ and the reaction time is 3-5h.

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