High-film-thickness water-based b1 basecoat for original automobile and preparation method and application thereof

Abstract

The application belongs to the technical field of materials, and particularly relates to a high-film-thickness type original factory water-based B1 base paint for automobiles, a preparation method and application thereof. The high-film-thickness type original factory water-based B1 base paint for automobiles comprises the following components and mass fractions: 15-25 parts of acrylic modified high molecular weight polyurethane, 5-10 parts of water-based acrylic resin emulsion, 5-15 parts of modified high molecular weight polyester, 4-8 parts of amino resin, 1-1.5 parts of surfactant, 1-1.5 parts of thickening agent, 0.2-0.5 parts of defoaming agent, 1-1.5 parts of dispersing agent, 0.5-1.5 parts of wetting and leveling agent, 15-25 parts of pigment, 1-1.5 parts of talc, 0.5-1 part of fumed silica, 0.5-2 parts of pH regulator, 1-5 parts of ethylene glycol butyl ether, 2-8 parts of cosolvent and 15-25 parts of water. The application improves the appearance qualification rate, and has excellent properties such as good flatness, good stone chip resistance, impact resistance and cupping resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of materials, and particularly relates to a high-film-thickness type automobile original factory water-based B1 basecoat paint as well as a preparation method and application thereof. BACKGROUND

[0002] In recent years, energy saving and environmental protection are the theme of world development, and automobile manufacturing enterprises in various countries of the world have invested a large amount of funds in this regard, continuously improve the process equipment and process level. Automobile painting is one of the main processes of automobile manufacturing, and its energy consumption accounts for about 60% of the total energy consumption of the automobile manufacturing process. Reducing energy consumption and reducing pollutant emissions in the painting process is of great significance to the protection of people's living environment. Therefore, the current automobile painting industry begins to gradually change from the traditional 3C2B process system to the compact process system, and B1B2 is a representative process among them.

[0003] The traditional 3C2B painting process flow is: electrophoresis (baking) - intermediate coating (baking) - color paint + clear paint (baking); the main process flow of water-based B1B2 process is: electrophoresis (baking) - color paint 1 + color paint 2 - pre-drying - clear paint (baking). Compared with the traditional 3C2B process, the biggest advantage of the water-based B1B2 process is that it reduces the intermediate coating, intermediate coating drying and intermediate coating polishing, greatly shortens the process flow, reduces the process time and saves energy. Compared with the traditional solvent-based paint, the currently used B1B2 water-based paint has the advantages of low organic solvent content, low VOC emission, low harm to human body, high safety, water-washable painting tools and equipment, less solvent use, etc. CN106543825A discloses a water-based metal flash basecoat paint, which comprises, by mass fraction, 50-60 parts of acrylic emulsion, 20-25 parts of water-based aluminum paste, 1-4 parts of butylene glycol butyl ether, 0.5-0.8 parts of silicone leveling agent, 20-25 parts of deionized water, 1-3 parts of neutralizing agent and 0.1-0.6 parts of defoaming agent. However, the water-based metal flash basecoat paint provided by the application is not necessarily suitable for water-based B1B2 process. The quality control difficulty of water-based B1B2 process paint film is much higher than that of traditional 3C2B process. The existing automobile original factory water-based B1 basecoat paint has the defects of high roughness requirement for the vehicle body substrate, easy generation of orange peel defects on the paint surface, poor stone chip resistance and the like. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a high-film-thickness water-based B1 base paint for original factory of automobile, a preparation method and application thereof. The high-film-thickness water-based B1 base paint for original factory of automobile provided by the present application has the properties of mid-coat paint, is compatible with the problem of excessively high requirement for roughness of the base material, and improves the qualified rate of appearance. The paint film obtained by the present application has excellent performance, strong operability, good flatness, stronger mechanical properties, good stone chip resistance, good hiding power and filling property, and excellent impact resistance and cupping resistance.

[0005] The technical scheme of the present application is:

[0006] A high-film-thickness water-based B1 base paint for original factory of automobile, comprising the following components and mass fractions thereof:

[0007] acrylic modified high molecular weight polyurethane 15-25 parts, water-based acrylic resin emulsion 5-10 parts, modified high molecular weight polyester 5-15 parts, amino resin 4-8 parts, surfactant 1-1.5 parts, thickening agent 1-1.5 parts, defoaming agent 0.2-0.5 parts, dispersant 1-1.5 parts, wetting and leveling agent 0.5-1.5 parts, pigment 15-25 parts, talc 1-1.5 parts, fumed silica 0.5-1 part, pH adjuster 0.5-2 parts, ethylene glycol butyl ether 1-5 parts, cosolvent 2-8 parts, and water 15-25 parts.

[0008] Further, the high-film-thickness water-based B1 base paint for original factory of automobile comprises the following components and mass fractions thereof:

[0009] acrylic modified high molecular weight polyurethane 20 parts, water-based acrylic resin emulsion 5 parts, modified high molecular weight polyester 10 parts, amino resin 5 parts, surfactant 1.5 parts, thickening agent 1.5 parts, defoaming agent 0.3 parts, dispersant 1 part, wetting and leveling agent 0.5 part, pigment 20 parts, talc 1 part, fumed silica 0.5 part, pH adjuster 2 parts, ethylene glycol butyl ether 2 parts, cosolvent 4 parts, and water 24.5 parts.

[0010] Further, the acrylic modified high molecular weight polyurethane is Zhanxin polyurethane resin 6466 / 36WA.

[0011] Further, the modified high molecular weight polyester is baked water-based polyester resin WATERSOL ZHW-1346.

[0012] Further, the cosolvent is one or both of isopropyl alcohol and isooctanol.

[0013] Further, the cosolvent is composed of isopropyl alcohol and isooctanol in a mass ratio of 1-5:0-5.

[0014] Furthermore, the aqueous acrylic resin emulsion is an alkali-swellable aqueous acrylic resin emulsion; the surfactant is an alkali diol surfactant; the thickener is an alkali-thickening thickener; and the pH adjuster is dimethylethanolamine.

[0015] Furthermore, the dispersant is BYK-192 dispersant; the wetting and leveling agent is BYK-345 wetting and leveling agent.

[0016] In addition, the present invention also provides a method for preparing a high film thickness automotive original water-based B1 base coat, the steps of which are as follows:

[0017] (1) Take the main cylinder A and add the following in sequence: acrylic modified high molecular weight polyurethane, modified high molecular weight polyester, 80% of the pH adjuster, water-based acrylic resin emulsion, and amino resin. Stir at 300-600 rpm for 15-20 minutes.

[0018] (2) Take another auxiliary cylinder B and add water, defoamer, dispersant, ethylene glycol butyl ether, pigment, talc powder and fumed silica in sequence at 40% of the formula amount. Grind the mixture at 900-1200 rpm until the fineness is below 5μm, the temperature is below 40℃, and the flow rate is 10-15L / min to obtain the primer slurry.

[0019] (3) After cooling the primer slurry obtained in step (2) to room temperature, add it to the main cylinder A in step (1) and stir at a speed of 300-600 rpm for 5-15 minutes. Add the formula amount of wetting and leveling agent, surfactant and thickener, and stir at a speed of 300-600 rpm for 15-20 minutes.

[0020] (4) Add the formula amount of cosolvent, the remaining amount of pH adjuster and the remaining amount of water to the main cylinder A of step (3), and stir at a speed of 600-900 rpm for 20-30 minutes to obtain the product.

[0021] Another object of the present invention is to provide the application of the aforementioned high film thickness automotive original water-based B1 base coat in automotive B1B2 compact coating process.

[0022] The quality control of the water-based B1B2 process is much more difficult than that of the traditional 3C2B process. First, in the original automotive B1B2 process, B1 usually needs to be applied thinly, with a film thickness in the range of 10-14um. The reasons for applying thinly include: thin coating will result in better smoothness; fast drying speed can prevent the B1 primer from being bitten by the topcoat. If the film is thicker, the following problems will exist: (1) B1 primer and topcoat B2 coating will be mutually soluble due to "wet contact", which will cause local or even large-area loss of gloss of the film, which will have a great impact on the appearance of the entire topcoat; (2) the micro-unevenness of the substrate will be transmitted to the paint surface; (3) the solvent evaporation during the paint drying process will cause the surface tension gradient to form a Bénard vortex; these will have a great impact on the smoothness of the composite coating; (4) B1 color paint is more like topcoat. Since B1 color paint is thinner, the roughness requirements of the car body substrate are higher, and it is also easier to produce orange peel defects on the paint surface. Therefore, the film thickness needs to be strictly controlled during construction, and the performance of the matching coating is also more demanding. Furthermore, since there is no interface between layer B1 and topcoat layer B2, the coating's ability to absorb impact energy decreases, thus increasing the likelihood of stone chips hitting the surface of the vehicle's steel plate and resulting in poor stone chip resistance.

[0023] To address the aforementioned technical challenges, this invention, through extensive creative experiments, innovatively employs modified high-molecular-weight polyester and acrylic-modified high-molecular-weight polyurethane as the main components, and increases the pigment-to-binder ratio (the ratio of pigment to resin in the coating). The B1 base coat design, when applied thickly, exhibits some filling properties, acting as both a base coat and an intermediate coat, while also addressing the issue of excessively high substrate roughness requirements, thus improving the appearance qualification rate. This results in a coating film with superior workability, smoothness, mechanical properties, stone chip resistance, wider color tinting, better hiding power and filling properties, and superior impact and cupping resistance. This invention, by adding fumed silica and talc, improves the pigment-to-binder ratio while simultaneously adding modified high-molecular-weight polyester to enhance appearance leveling and maintain important properties, thus solving the technical difficulties inherent in the aforementioned water-based B1B2 process.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] (1) The high film thickness automotive original water-based B1 base coat provided by the present invention serves as a base coat and also has the properties of an intermediate coat, while also addressing the issue of excessively high requirements for substrate roughness, thereby improving the appearance qualification rate.

[0026] (2) This invention has strong compatibility and can be used with various color paints of the original car manufacturer's B1B2 process. The light transmittance of the coating meets the relevant technical requirements.

[0027] (3) In the original equipment manufacturer (OEM) B1B2 process, B1 usually requires a thin coating with a film thickness in the range of 10-14 μm. However, the film thickness using this invention is in the range of 20-25 μm, overcoming the technical difficulties of thicker paint films in existing technologies. The paint film obtained using this invention has excellent performance, strong operability, good smoothness, stronger mechanical properties, good stone chip resistance, wider color tinting, better hiding power and filling properties, better impact resistance and cupping resistance, low volatile organic compounds (VOCs), meets national environmental protection requirements, is green and environmentally friendly, and meets the paint film index requirements of OEM paints. Detailed Implementation

[0028] The present invention will be further described below through specific embodiments, but this is not a limitation of the present invention. Those skilled in the art can make various modifications or improvements based on the basic idea of ​​the present invention, but as long as they do not depart from the basic idea of ​​the present invention, they are all within the scope of the present invention.

[0029] The purchase information of each raw material in the following examples and comparative examples is shown in Table 1.

[0030] Table 1: Information on the suppliers of each raw material

[0031]

[0032]

[0033] Example 1: A high film thickness automotive original water-based B1 base coat

[0034] The high film thickness automotive original water-based B1 base coat comprises the following components and their weight percentages: 15 parts acrylic-modified high molecular weight polyurethane, 5 parts water-based acrylic resin emulsion, 5 parts modified high molecular weight polyester, 4 parts amino resin, 1 part surfactant, 1 part thickener, 0.2 parts defoamer, 1 part BYK-192 dispersant, 0.5 parts BYK-345 wetting and leveling agent, 15 parts pigment, 1 part talc, 0.5 parts fumed silica, 0.5 parts pH adjuster, 1 part ethylene glycol butyl ether, 2 parts cosolvent, and 15 parts water; the acrylic-modified high molecular weight polyurethane is Zhanxin polyurethane resin. 6466 / 36WA; the modified high molecular weight polyester is a baking-type waterborne polyester resin WATERSOL ZHW-1346; the cosolvent is composed of isopropanol and isooctanol in a mass ratio of 1:5; the waterborne acrylic resin emulsion is an alkali-swellable waterborne acrylic resin emulsion; the surfactant is an alkali glycol surfactant; the thickener is an alkali-thickening thickener; the fumed silica is Evonik AEROSIL R972; and the pH adjuster is dimethylethanolamine.

[0035] The preparation method of high film thickness automotive original water-based B1 base coat, the steps are as follows:

[0036] (1) Take the main cylinder A and add the following in sequence: acrylic modified high molecular weight polyurethane, modified high molecular weight polyester, 80% of the pH adjuster, water-based acrylic resin emulsion, and amino resin. Stir at 300 rpm for 15 minutes.

[0037] (2) Take another auxiliary cylinder B and add water, defoamer, dispersant, ethylene glycol butyl ether, pigment, talc powder and fumed silica in sequence at 40% of the formula amount. Grind the mixture at 900 rpm until the fineness is below 5 μm, the temperature is below 40℃ and the flow rate is 10 L / min to obtain the primer slurry.

[0038] (3) After cooling the primer slurry obtained in step (2) to room temperature, add it to the main cylinder A in step (1), stir at 3000 rpm for 5 minutes, add the formula amount of wetting leveling agent, surfactant and thickener, and stir at 300 rpm for 15 minutes.

[0039] (4) Add the formula amount of cosolvent, the remaining amount of pH adjuster and the remaining amount of water to the main cylinder A of step (3), and stir at 600 rpm for 20 minutes to obtain the product.

[0040] Example 2: A high film thickness automotive original water-based B1 base coat

[0041] The high film thickness automotive original water-based B1 base coat comprises the following components and their weight percentages: 25 parts acrylic-modified high molecular weight polyurethane, 10 parts water-based acrylic resin emulsion, 15 parts modified high molecular weight polyester, 8 parts amino resin, 1.5 parts surfactant, 1.5 parts thickener, 0.5 parts defoamer, 1.5 parts BYK-192 dispersant, 1.5 parts BYK-345 wetting and leveling agent, 25 parts pigment, 1.5 parts talc, 1 part fumed silica, 2 parts pH adjuster, 5 parts ethylene glycol butyl ether, 8 parts cosolvent, and 25 parts water; the acrylic-modified high molecular weight polyurethane is Zhanxin polyurethane resin. 6466 / 36WA; the modified high molecular weight polyester is a baking-type waterborne polyester resin WATERSOL ZHW-1346; the cosolvent is isopropanol; the waterborne acrylic resin emulsion is an alkali-swellable waterborne acrylic resin emulsion; the surfactant is an alkali glycol surfactant; the thickener is an alkali-thickening thickener; the fumed silica is Evonik AEROSIL R972; and the pH adjuster is dimethylethanolamine.

[0042] The preparation method of high film thickness automotive original water-based B1 base coat, the steps are as follows:

[0043] (1) Take the main cylinder A and add the following in sequence: acrylic modified high molecular weight polyurethane, modified high molecular weight polyester, 80% of the pH adjuster, water-based acrylic resin emulsion, and amino resin. Stir at 600 rpm for 20 minutes.

[0044] (2) Take another auxiliary cylinder B and add water, defoamer, dispersant, ethylene glycol butyl ether, pigment, talc powder and fumed silica in sequence at 40% of the formula amount. Grind the mixture at 1200 rpm until the fineness is below 5 μm, the temperature is below 40℃ and the flow rate is 15 L / min to obtain the primer slurry.

[0045] (3) After cooling the primer slurry obtained in step (2) to room temperature, add it to the main cylinder A in step (1), stir at 600 rpm for 15 minutes, add the formula amount of wetting and leveling agent, surfactant and thickener, and stir at 600 rpm for 20 minutes.

[0046] (4) Add the formula amount of cosolvent, the remaining amount of pH adjuster and the remaining amount of water to the main cylinder A of step (3), and stir at 900 rpm for 30 minutes to obtain the product.

[0047] Example 3: A high film thickness automotive original water-based B1 base coat

[0048] The high film thickness automotive original water-based B1 base coat comprises the following components and their weight percentages: 20 parts acrylic-modified high molecular weight polyurethane, 5 parts water-based acrylic resin emulsion, 10 parts modified high molecular weight polyester, 5 parts amino resin, 1.5 parts surfactant, 1.5 parts thickener, 0.3 parts defoamer, 1 part BYK-192 dispersant, 0.5 parts BYK-345 wetting and leveling agent, 20 parts pigment, 1 part talc, 0.5 parts fumed silica, 2 parts pH adjuster, 2 parts ethylene glycol butyl ether, 4 parts cosolvent, and 24.5 parts water; the acrylic-modified high molecular weight polyurethane is Zhanxin polyurethane resin. 6466 / 36WA; the modified high molecular weight polyester is a baking-type waterborne polyester resin WATERSOL ZHW-1346; the cosolvent is isopropanol; the waterborne acrylic resin emulsion is an alkali-swellable waterborne acrylic resin emulsion; the surfactant is an alkali glycol surfactant; the thickener is an alkali-thickening thickener; the fumed silica is Evonik AEROSIL R972; and the pH adjuster is dimethylethanolamine.

[0049] The preparation method of high film thickness automotive original water-based B1 base coat includes the following steps:

[0050] (1) Take the main cylinder A and add the following in sequence: acrylic modified high molecular weight polyurethane, modified high molecular weight polyester, 80% of the pH adjuster, water-based acrylic resin emulsion, and amino resin. Stir at 500 rpm for 17 minutes.

[0051] (2) Take another auxiliary cylinder B and add water, defoamer, dispersant, ethylene glycol butyl ether, pigment, talc powder and fumed silica in sequence at 40% of the formula amount. Grind the mixture at 1000 rpm until the fineness is below 5 μm, the temperature is below 40℃ and the flow rate is 12 L / min to obtain the primer slurry.

[0052] (3) After cooling the primer slurry obtained in step (2) to room temperature, add it to the main cylinder A in step (1), stir at 400 rpm for 10 minutes, add the formula amount of wetting leveling agent, surfactant and thickener, and stir at 400 rpm for 17 minutes.

[0053] (4) Add the formula amount of cosolvent, the remaining amount of pH adjuster and the remaining amount of water to the main cylinder A of step (3), and stir at 800 rpm for 25 minutes to obtain the product.

[0054] Comparative Example 1: A type of original equipment manufacturer (OEM) water-based B1 base coat for automobiles

[0055] The original automotive waterborne B1 base coat comprises the following components and their weight percentages: 20 parts DSM Neopac E-123 polyurethane resin, 5 parts waterborne acrylic resin emulsion, 10 parts modified high molecular weight polyester, 5 parts amino resin, 1.5 parts surfactant, 1.5 parts thickener, 0.3 parts defoamer, 1 part BYK-192 dispersant, 0.5 parts BYK-345 wetting and leveling agent, 20 parts pigment, 1 part talc, 0.5 parts fumed silica, 2 parts pH adjuster, 2 parts ethylene glycol butyl ether, 4 parts cosolvent, and 24.5 parts water; the modified high molecular weight polyester is a baking-type waterborne polyester resin, WATERSOL. ZHW-1346; the cosolvent is isopropanol; the aqueous acrylic resin emulsion is an alkali-swellable aqueous acrylic resin emulsion; the surfactant is acetylenic diol surfactant; the thickener is an alkali-thickening thickener; the fumed silica is Evonik AEROSIL R972; the pH adjuster is dimethylethanolamine.

[0056] The preparation method of the automotive original water-based B1 base coat is similar to that in Example 3.

[0057] The difference from Example 3 is that the Zhanxin polyurethane resin is used. TW6466 / 36WA was replaced with DSM Neopac E-123 polyurethane resin.

[0058] Comparative Example 2: A type of original equipment manufacturer (OEM) water-based B1 base coat for automobiles

[0059] The original factory water-based B1 base coat for automobiles comprises the following components and their weight percentages: 20 parts acrylic-modified high molecular weight polyurethane, 5 parts water-based acrylic resin emulsion, and Zhanxin alkyd resin. The composition includes: 10 parts AZ 541w 42 / WA, 5 parts amino resin, 1.5 parts surfactant, 1.5 parts thickener, 0.3 parts defoamer, 1 part BYK-192 dispersant, 0.5 parts BYK-345 wetting and leveling agent, 20 parts pigment, 1 part talc, 0.5 parts fumed silica, 2 parts pH adjuster, 2 parts ethylene glycol butyl ether, 4 parts cosolvent, and 24.5 parts water; the acrylic-modified high molecular weight polyurethane is Zhanxin polyurethane resin. TW 6466 / 36WA; the cosolvent is isopropanol; the aqueous acrylic resin emulsion is an alkali-swellable aqueous acrylic resin emulsion; the surfactant is acetylenic diol surfactant; the thickener is an alkali-thickening thickener; the fumed silica is Evonik AEROSIL R972; and the pH adjuster is dimethylethanolamine.

[0060] The preparation method of the automotive original water-based B1 base coat is similar to that in Example 3.

[0061] The difference from Example 3 is that the baking-type waterborne polyester resin WATERSOL ZHW-1346 is replaced with Zhanxin alkyd resin. AZ 541w 42 / WA.

[0062] Comparative Example 3: A type of original equipment manufacturer (OEM) water-based B1 base coat for automobiles

[0063] The high film thickness automotive original water-based B1 base coat comprises the following components and their mass fractions: 20 parts acrylic-modified high molecular weight polyurethane, 5 parts water-based acrylic resin emulsion, 10 parts modified high molecular weight polyester, 5 parts amino resin, 1.5 parts surfactant, 1.5 parts thickener, 0.3 parts defoamer, 1 part BYK-192 dispersant, 0.5 parts BYK-345 wetting and leveling agent, 20 parts pigment, 1 part talc, 0.5 parts Elementis DeuRheo 201P, 2 parts pH adjuster, 2 parts ethylene glycol butyl ether, 4 parts cosolvent, and 24.5 parts water; the acrylic-modified high molecular weight polyurethane is Zhanxin polyurethane resin. 6466 / 36WA; the modified high molecular weight polyester is a baking-type waterborne polyester resin WATERSOLZHW-1346; the cosolvent is isopropanol; the waterborne acrylic resin emulsion is an alkali-swellable waterborne acrylic resin emulsion; the surfactant is an alkali glycol surfactant; the thickener is an alkali-thickening thickener; the fumed silica is Evonik AEROSIL R972; and the pH adjuster is dimethylethanolamine.

[0064] The preparation method of the automotive original water-based B1 base coat is similar to that in Example 3.

[0065] The difference from Example 3 is that the fumed silica is replaced with Elementis DeuRheo201P.

[0066] Comparative Example 4: A high film thickness automotive original water-based B1 base coat

[0067] The high film thickness automotive original water-based B1 base coat comprises the following components and their mass percentages: 20 parts acrylic-modified high molecular weight polyurethane, 5 parts water-based acrylic resin emulsion, 10 parts modified high molecular weight polyester, 5 parts amino resin, 1.5 parts surfactant, 1.5 parts thickener, 0.3 parts defoamer, 1 part BYK-192 dispersant, 0.5 parts BYK-345 wetting and leveling agent, 20 parts pigment, 0.5 parts talc, 1 part fumed silica, 2 parts pH adjuster, 2 parts ethylene glycol butyl ether, 4 parts cosolvent, and 24.5 parts water; the acrylic-modified high molecular weight polyurethane is Zhanxin polyurethane resin. 6466 / 36WA; the modified high molecular weight polyester is a baking-type waterborne polyester resin WATERSOL ZHW-1346; the cosolvent is isopropanol; the waterborne acrylic resin emulsion is an alkali-swellable waterborne acrylic resin emulsion; the surfactant is an alkali glycol surfactant; the thickener is an alkali-thickening thickener; the fumed silica is Evonik AEROSIL R972; and the pH adjuster is dimethylethanolamine.

[0068] The preparation method of the automotive original water-based B1 base coat is similar to that in Example 3.

[0069] The difference from Example 3 is that the mass fraction of talc powder is adjusted from 1 part to 0.5 parts, and the mass fraction of fumed silica is adjusted from 0.5 parts to 1 part.

[0070] Experiment 1: Performance Testing

[0071] 1. Test materials: High film thickness automotive original water-based B1 base coat prepared in Examples 1, 2, and 3, and automotive original water-based B1 base coat prepared in Comparative Examples 1, 2, 3, and 4.

[0072] 2. The testing items and methods are shown in Table 2.

[0073] Table 2. Testing Items and Methods

[0074]

[0075]

[0076] 3. The test results are shown in Table 3.

[0077] Table 3. Comprehensive performance test results of the present invention

[0078]

[0079]

[0080] Table 4. Comprehensive performance test results for comparative examples 1-4

[0081]

[0082]

[0083]

[0084] As can be seen from Table 3, based on the reasonable combination and ratio of each component, the high film thickness automotive original water-based B1 base coat prepared in Examples 1 to 3 of this invention achieves an adhesion grade of 0, high hardness, good water resistance, strong impact resistance, strong crack resistance, good acid, alkali and damp heat resistance, and excellent storage stability, stone impact resistance and aging resistance.

[0085] As can be seen from the comparison of Tables 3 and 4, compared with Comparative Examples 1 to 4, changing the formulation materials or proportions will lead to a serious decline in key performance, highlighting the synergistic effect of each component in the high film thickness automotive original water-based B1 base coat prepared by the present invention, which has a more superior comprehensive performance.

Claims

1. A high film thickness type automotive original water-based B1 basecoat paint, characterized by, The components and their mass parts include: acrylic modified high molecular weight polyurethane 15~25 parts, water-based acrylic resin emulsion 5~10 parts, modified large molecular weight polyester 5~15 parts, amino resin 4~8 parts, surfactant 1~1.5 parts, thickening agent 1~1.5 parts, defoaming agent 0.2~0.5 parts, dispersant 1~1.5 parts, wetting and leveling agent 0.5~1.5 parts, pigment 15~25 parts, talc 1~1.5 parts, fumed silica 0.5~1 parts, pH adjuster 0.5~2 parts, ethylene glycol butyl ether 1~5 parts, cosolvent 2~8 parts, water 15~25 parts; The acrylic modified high molecular weight polyurethane is Zhanxin polyurethane resin DAOTAN®TW 6466 / 36WA; The modified large molecular weight polyester is baked water-based polyester resin WATERSOL ZHW-1346; The cosolvent is one or both of isopropyl alcohol and isooctanol; The water-based acrylic resin emulsion is alkali swelling type water-based acrylic resin emulsion.

2. The high film thickness type automotive original water-based Bl basecoat according to claim 1, characterized in that, The components and their mass parts include: acrylic modified high molecular weight polyurethane 20 parts, water-based acrylic resin emulsion 5 parts, modified large molecular weight polyester 10 parts, amino resin 5 parts, surfactant 1.5 parts, thickening agent 1.5 parts, defoaming agent 0.3 parts, dispersant 1 part, wetting and leveling agent 0.5 parts, pigment 20 parts, talc 1 part, fumed silica 0.5 parts, pH adjuster 2 parts, ethylene glycol butyl ether 2 parts, cosolvent 4 parts, water 24.5 parts.

3. The high film thickness type automotive original water-based B1 basecoat paint according to claim 1, characterized by, The cosolvent is composed of isopropyl alcohol and isooctanol in a mass ratio of 1~5:0~5.

4. The high film thickness type automotive original water-based Bl basecoat according to claim 1 or 2, characterized in that, The surfactant is acetylenic diol surfactant; the thickening agent is alkali thickening type thickening agent; and the pH adjuster is dimethyl ethanolamine.

5. The high film thickness type automotive original water-based Bl basecoat according to claim 1 or 2, characterized in that, The dispersant is BYK-192 dispersant; and the wetting and leveling agent is BYK-345 wetting and leveling agent.

6. The preparation method of high film thickness type automotive original water-based B1 basecoat according to any one of claims 1-5, characterized in that, The steps include: (1) take the main cylinder A, and sequentially add the formula amount of acrylic modified high molecular weight polyurethane, modified large molecular weight polyester, 80% of the formula amount of pH adjuster, water-based acrylic resin emulsion, and amino resin, and stir at a speed of 300~600 rpm for 15~20 minutes; (2) take another auxiliary cylinder B, and sequentially add the formula amount of 40% water, defoaming agent, dispersant, ethylene glycol butyl ether, pigment, talc, and fumed silica, and sand mill under the condition of 900~1200 rpm, fineness of 5 μm or less, temperature of 40℃ or less, and flow rate of 10~15 L / min, to obtain a primer slurry; after cooling the primer slurry obtained in step (2) to room temperature, add it to the main cylinder A of step (1), and stir at a speed of 300~600 rpm for 5~15 minutes, and then add the formula amount of wetting and leveling agent, surfactant, and thickening agent, and stir at a speed of 300~600 rpm for 15~20 minutes; add the formula amount of cosolvent, the remaining amount of pH adjuster, and the remaining amount of water to the main cylinder A of step (3), and stir at a speed of 600~900 rpm for 20~30 minutes, to obtain the product.

7. The use of the high film thickness type automotive OEM waterborne B1 basecoat according to any one of claims 1 to 5 in a B1 B2 compact coating process for automobiles.

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