A coating composition having an electroplated silver effect and a method for its production

Abstract

The present application discloses a paint composition with electroplated silver effect, which comprises aluminum silver paste, aluminum powder orientation agent, thermosetting acrylic resin or amino resin, acrylic microgel solution, black paste, solvent and auxiliary agent and the like. According to the present application, mirror surface effect comparable to electroplated aluminum silver paste is realized, the comprehensive performance of the coating film is excellent, the cycle resistance and weather resistance are ensured, and the cost is reduced. The present application also provides a preparation method of the above-mentioned paint composition.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polymer material preparation, and relates to a coating composition with high performance and good appearance brightness and a preparation method thereof. BACKGROUND

[0002] Electroplated silver coating is a coating material that can meet the appearance and quality requirements of high-grade products. It is usually made of electroplated aluminum silver paste (i.e. vacuum metallized aluminum suspension, VMP) to achieve a coating film with a mirror-like effect comparable to electroplated silver. The electroplated aluminum silver paste is usually made of high-purity aluminum as raw material and is a non-floating mirror silver produced by a unique gas-phase metallized pigment process. Compared with ordinary aluminum silver paste, the thickness of the electroplated aluminum silver paste is only nanoscale, the diameter-thickness ratio is large, generally above 200, the metallic feeling is excellent, and the brightness is high.

[0003] Aluminum silver paste can be generally divided into two categories: floating type and non-floating type. In the floating type aluminum silver paste, due to low surface tension, aluminum flakes are arranged in a direction near the surface of the paint film to form an opaque silver film with extremely high reflectivity and electroplated chromium effect, but cannot have good adhesion with the upper and lower layers and is easy to fall off from the surface of the paint film. This opaque property makes it usually applied in roof coating, maintenance, corrosion-resistant coating, reflective coating, imitation plating effect coating and the like with high protection requirements, but cannot be applied in the field of high-performance paint film such as automobile. The non-floating type aluminum silver paste has excellent color depth, can be completely wetted by the coating, and is evenly distributed in the entire paint film. It has stable adhesion with the upper and lower layers of the paint film, and the formed coating film has a different appearance from the floating type aluminum silver paste. It can be mixed with various pigments and applied to various systems, so it has a unique metallic effect for industrial coating.

[0004] However, the existing process for producing electroplated aluminum silver paste is relatively complex, and the prepared aluminum silver paste often cannot meet the requirements. For example, in the non-floating type aluminum silver paste, snowflake-shaped aluminum paste particles are used, which form a paste after being mixed with a solvent. After light is incident on the coating film, it is reflected and diffusely reflected between the aluminum flakes, and the reflectivity is poor, which cannot achieve a good mirror effect. Moreover, the larger the particle size of the aluminum flake particles in the coating film, the stronger the visual particle feeling, and the more rough the visual coating film. For another example, the nanoscale electroplated aluminum silver paste is also prone to deformation, and it is easy to aggregate or react with water in the air to generate aluminum oxide and hydrogen. A large amount of solvent is needed to protect it during the reaction process, and the final solid content is also much lower than the solid content of about 60-80% of the conventional aluminum silver paste, usually only about 10%. The unit price of the electroplated aluminum silver paste is about 10-20 times that of the ordinary aluminum silver paste, and the cost is very high.

[0005] With the higher requirements of the appearance of the color of the automobile body by the consumers, in addition to the large area of the automobile body, the easy corrosion of the steel material, the high comprehensive performance (weather resistance, hiding property, etc.) of the coating film of the automobile body, the long time circulation use of the coating in the production line, the low cost and other factors, it is necessary to develop a coating composition which can meet the requirements of high performance coating in the field of automobile, so that it has the high mirror effect of electroplating, excellent adhesion, good corrosion resistance and cycle resistance. SUMMARY

[0006] In view of the defects of the prior art, the first object of the present application is to provide a coating composition with high performance and good appearance brightness, which is a solvent type high molecular film system.

[0007] Another object of the present application is to provide a preparation method of the above-mentioned coating composition.

[0008] Still another object of the present application is to provide a method for preparing a composite coating layer using the above-mentioned coating composition.

[0009] To achieve the above objects, the technical solutions adopted by the present application are as follows:

[0010] The first aspect of the present application provides a coating composition with electroplated silver effect, which comprises the following components by weight parts: 0.5 to 1.5 parts of aluminum silver paste, 0.1 to 0.6 parts of aluminum powder orientation agent, 8.0 to 10.0 parts of thermosetting acrylic resin or amino resin, 2.0 to 8.0 parts of acrylic microgel solution, 4.0 to 8.0 parts of black paste, 60 to 80 parts of solvent, and 1.0 to 5.0 parts of auxiliary agent.

[0011] In another preferred embodiment, the aluminum silver paste is 0.5 to 1.0 parts.

[0012] In another preferred embodiment, the aluminum powder orientation agent is 0.2 to 0.5 parts, preferably 0.1 to 0.3 parts.

[0013] In another preferred embodiment, the acrylic microgel solution is 4.0 to 6.0 parts.

[0014] In another preferred embodiment, the black paste is 5.0 to 7.0 parts.

[0015] In another preferred embodiment, the solvent is 65.0 to 75.0 parts.

[0016] In another preferred embodiment, the auxiliary agent is 2.0 to 4.0 parts.

[0017] The thermosetting acrylic resin of the present application is a resin copolymerized from acrylic monomers. As an example, the thermosetting acrylic resin of the present application can be a mixture of 65% thermosetting acrylic acid and 35% solvent (e.g., S-100). The thermosetting acrylic acid is selected from the group consisting of methyl acrylate, butyl acrylate, or butyl acrylate.

[0018] The acrylic microgel solution of the present application is formed by emulsion polymerization of 20% water-soluble acrylic monomer as a dispersed phase and 80% organic solvent butyl acetate as a continuous phase to form a micron-sized water-in-oil microgel emulsion.

[0019] In another preferred embodiment, the coating composition further comprises an optional additional colorant, the additional colorant being present in an amount of less than or equal to 5 parts by weight, preferably 2 to 4 parts by weight.

[0020] In another preferred embodiment, the aluminum silver paste is a non-floating type aluminum silver paste. The non-floating type aluminum silver paste can be uniformly distributed in the coating film, ensuring that the color and properties of the coating film are uniform and stable, and that the coating film has good adhesion to the upper and lower layers, ensuring the performance of the composite coating.

[0021] In another preferred embodiment, the aluminum silver paste has a particle size D50 of 8 μm to 12 μm. When the particle size D50 of the aluminum silver paste is less than 8 μm, the hiding power and light resistance are reduced. When the particle size D50 of the aluminum silver paste is greater than 12 μm, the particle size is too large, which affects the FF properties of the coating film.

[0022] In another preferred embodiment, the aluminum silver paste is a silver coin type aluminum silver paste. As known to those skilled in the art, the type of aluminum silver paste can be selected from ECA HYDROMIC N 8790, Dongyang FD-5090, and Z0684N. The silver coin type aluminum silver paste can provide the coating film with good FF properties and reduce the deformation, breakage, and color and quality abnormalities of the aluminum silver paste caused by long-term circulation in the production line circulation system.

[0023] In another preferred embodiment, the aluminum silver paste has an aspect ratio of 60:1 to 80:1. The aspect ratio here refers to the ratio of the length of the aluminum sheet to the diameter of the cross section of the aluminum sheet. This specific aspect ratio allows the aluminum silver paste to have a certain shape and particle size ratio, which ensures that the color paint after spraying has good resistance to circulation. The aluminum silver paste of the present application has good flop (also known as "FF property"), which is the property of the brightness changing with the angle of viewing the coated object, that is, the contrast between light (light part) and dark (dark part). If the aspect ratio is too low (e.g., less than 60:1), the hiding power is poor. If the aspect ratio is too high (e.g., greater than 80:1), the aluminum silver paste is too thin and is prone to deformation and breakage after long-term circulation in the circulation system.

[0024] In another preferred embodiment, the black paste is a color paste prepared from carbon black.

[0025] In another preferred embodiment, the other color paste is a phthalocyanine blue or red pre-treated color paste.

[0026] As known to those skilled in the art, the black paste or other color paste can be prepared by various methods, which are not particularly limited in the present application. For example, some resins (e.g. acrylic resin), pigments, dispersing aids, etc. can be mixed uniformly, ground to a specified particle size, and then added with a required solvent to adjust to a specified viscosity and non-volatility, and then the color is confirmed to be qualified.

[0027] In another preferred embodiment, the aluminum powder orienting agent is butyl cellulose acetate.

[0028] In another preferred embodiment, the thermosetting acrylic resin can be HR-7050 available from Mitsubishi Chemical.

[0029] In another preferred embodiment, the amino resin is n-butylated melamine formaldehyde resin. As an example, the amino resin can be BR 20SE available from Changchun Chemical.

[0030] In another preferred embodiment, the solvent is a mixture of ethyl acetate and aromatic hydrocarbon solvent.

[0031] In another preferred embodiment, the mass ratio of ethyl acetate to aromatic hydrocarbon solvent in the solvent is 1-3:6-10. Preferably, the aromatic hydrocarbon solvent is a mixture of S-100 aromatic hydrocarbon solvent and S-150 aromatic hydrocarbon solvent available from Huaren Chemical. Preferably, the mass ratio of ethyl acetate, S-100 aromatic hydrocarbon solvent, and S-150 aromatic hydrocarbon solvent is 1-3:3-5:3-5.

[0032] In another preferred embodiment, the auxiliary agent contains the following components by weight: 0.1-0.3 parts of a leveling agent, 0.4-0.6 parts of a resistance adjusting agent, and 0.1-0.3 parts of a quick-drying agent.

[0033] In another preferred embodiment, the leveling agent is selected from an acid group-containing copolymer solution or a polyether-modified polydimethylsiloxane solution. Preferably, the leveling agent is BYK-110 or BYK-306 available from BYK.

[0034] In another preferred embodiment, the resistance adjusting agent is a carboxylate alcohol ammonium salt solution or methanol. Preferably, the resistance adjusting agent is BYK-ES 80 available from BYK.

[0035] In another preferred embodiment, the quick-drying agent is SCAT-2L available from Nippon Shokubai Co., Ltd.

[0036] The second aspect of the present application provides a preparation method of the coating composition of the first aspect of the present application, comprising the steps of:

[0037] (5) in the first container, add acrylic microgel solution to the solvent, stir evenly; under the stirring speed of 500 rpm, add amino resin at 20 kg / min, stir evenly, and then add leveling agent;

[0038] (6) in the second container, add aluminum silver paste to the solvent, stir evenly;

[0039] (7) add the mixture of the second container to the first container, stir evenly;

[0040] (8) add aluminum powder orientation agent, color paste and solvent to the first container, stir evenly, to obtain the coating composition.

[0041] The third aspect of the present application provides a use of the coating composition according to the first aspect of the present application as a composite coating, which is achieved by first spraying a primer on a metal substrate, and spraying the coating composition to obtain the composite coating.

[0042] Due to the adoption of the above technical solutions, the present application has the following advantages and beneficial effects:

[0043] 1. The specific aluminum silver paste is used to replace the traditional vacuum aluminum plating suspension, which realizes a mirror surface effect comparable to electroplated aluminum silver paste, has excellent comprehensive performance of the coating film, guarantees the cycle resistance and weather resistance, and reduces the cost.

[0044] 2. The diameter-thickness ratio range of the aluminum silver paste provided by the present application is much lower than that of the vacuum aluminum plating suspension, and the aluminum silver paste will not be deformed and broken after long-time circulation, which can meet the long-time (1 to 3 months) circulation in the production line circulation system of the automobile industry.

[0045] 3. By using the aluminum powder orientation agent, the solid content and viscosity of the coating composition are reduced, so that the coating can form a film at a low film thickness to realize high FF, and the low film thickness enables the color paint to be sprayed in one pass instead of two passes, and the other pass can be sprayed with a base color paint to guarantee the hiding power and weather resistance.

[0046] 4. After the viscosity of the color paint is reduced as a whole, more pigments and fillers can be added subsequently, so that the color paint has better light transmission resistance and hiding power, and the film thickness of the color paint is further reduced, so that the arrangement of the aluminum silver paste is more uniform and flat, and a good mirror surface effect is achieved.

[0047] 5. By increasing the pigment-to-binder ratio of the coating, the film thickness of the color paint is reduced, good mirror surface effect is achieved, and the hiding power and weather resistance are guaranteed.

[0048] 6. The coating composition of the present application is beneficial to the improvement of the automobile body painting process, because of its low viscosity and better hiding power, the intermediate coating process can be cancelled, the steps of the painting process are less, the flatness of the substrate is improved, and the mirror surface effect is guaranteed. Attached Figure Description

[0049] Figure 1a The image shows a 300x magnified electron microscope image of the electroplated silver paste, revealing that the electroplated silver aluminum powder is fine and thin.

[0050] Figure 1b The image shows a 300x electron microscope magnification of the aluminum silver paste used in this invention, with a suitable aspect ratio.

[0051] Figure 1c The image shows a 300x magnified electron microscope image of a typical electroplated aluminum silver paste, revealing its coarse particle size and small aspect ratio.

[0052] Figure 2a The image shown is a 900x magnified electron microscope image of the aluminum silver paste (9 μm in diameter) used in this invention.

[0053] Figure 2b This shows a 900x magnified electron microscope image of a typical electroplated aluminum silver paste (15 μm in diameter). Detailed Implementation

[0054] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0055] The purpose of the present invention will be illustrated by the following examples. The components of the composition are described in parts by weight as a general standard. Unless otherwise specified, for the sake of brevity, "parts" and parts by weight are the same in the embodiments of the present invention.

[0056] The following are the reagents used in the examples:

[0057] Aluminum powder orientation agent: purchased from YTOMAN CAB-381-0.5.

[0058] Silver dollar type aluminum silver paste: purchased from Dongyang FD-5090D50 9μm.

[0059] Leveling agents: purchased from BYK DISPERBYK-110 and BYK-306.

[0060] Resistance regulator: purchased from BYK-ES 80.

[0061] S100 and S150 solvents: purchased from Hualun Chemical.

[0062] The drying agent was purchased from: SCAT-2L by Nippon Kasei Corporation.

[0063] Example 1

[0064] In the first container, 1.40 parts of ethyl acetate was added to 4.69 parts of the acrylic acid microgel solution, stirred uniformly, and the fineness range was confirmed to be less than or equal to 5 μm. 6.21 parts of the amino resin was added in a fine stream under high-speed stirring, and the fineness range was confirmed to be less than or equal to 5 μm. 2.66 parts of the acrylic resin, 3.22 parts of the leveling aid, and 0.23 parts of the leveling agent were sequentially added, and dispersed uniformly.

[0065] In the second container, 0.83 parts of ethyl acetate was added to 0.75 parts of the aluminum silver paste, and dispersed uniformly. The fineness range was confirmed to be less than or equal to 20 μm.

[0066] The mixture of the second container was added to the first container, and stirred uniformly. Finally, 0.23 parts of the leveling agent, 0.23 parts of the aluminum powder orientation agent, 4.46 parts of ethyl acetate, 0.24 parts of the drier, and 0.48 parts of methanol were added to the first container, and dispersed uniformly. 5.15 parts of the black paste, 2.16 parts of the blue paste, and 0.62 parts of the purple paste were added to adjust the color. The fineness range was confirmed to be less than or equal to 20 μm. After passing, 33 parts of S-100 and 33 parts of S-150 were added, and stirred uniformly, thereby obtaining the coating composition.

[0067] Spraying was performed according to the process parameters described in Table 1 below.

[0068] Table 1

[0069]

[0070] The coating prepared was subjected to the following performance test items: appearance, FF property, hiding power, weather resistance, and the like.

[0071] Table 2

[0072]

[0073]

[0074] Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were prepared according to the formulations shown in Table 2 above.

[0075] Preparation method of Example 1:

[0076] Using a container, Example 1 was prepared. First, 6 and 7 were added, and dispersed uniformly. The fineness was confirmed to be qualified. 8 was added in a fine stream under high-speed stirring, and the fineness was confirmed to be qualified. 9, 10, and 11 were sequentially added, and dispersed uniformly.

[0077] Using another container, 1 and 2 were added under stirring, and dispersed uniformly after immersion. The fineness was confirmed to be qualified.

[0078] Into the above container, add 11, 12, 13, 14 and 15, disperse evenly, add 3, 4 and 5 to adjust the color, confirm whether the fineness of the product is qualified, after qualified, add 16 and 17, sample spray, confirm whether the viscosity, NV, color and other properties meet the design requirements, confirm the appearance, color, hiding power and weather resistance of the coating film.

[0079] Preparation method of Comparative Example 1:

[0080] Use a container to prepare Comparative Example 1, first add 6 and 7, disperse evenly, confirm whether the fineness is qualified; add 8 in a fine stream under high-speed stirring, confirm the fineness is qualified, then add 9, 10 and 11 in turn, disperse evenly

[0081] Use another container, add 1 and 2 under stirring, disperse evenly after soaking, confirm whether the fineness is qualified;

[0082] Into the above container, add 11, 12, 13, 14 and 15, disperse evenly, add 3, 4 and 5 to adjust the color, confirm whether the fineness of the product is qualified, after qualified, add 16 and 17, sample spray, confirm whether the viscosity, NV, color and other properties meet the design requirements, confirm the appearance, color, hiding power and weather resistance of the coating film.

[0083] Preparation method of Comparative Example 2:

[0084] Use a container to prepare Comparative Example 2, first add 6 and 7, disperse evenly, confirm whether the fineness is qualified; add 8 in a fine stream under high-speed stirring, confirm the fineness is qualified, then add 9, 10 and 11 in turn, disperse evenly

[0085] Use another container, add 1 and 2 under stirring, disperse evenly after soaking, confirm whether the fineness is qualified;

[0086] Into the above container, add 11, 12, 13, 14 and 15, disperse evenly, add 3, 4 and 5 to adjust the color, confirm whether the fineness of the product is qualified, after qualified, add 16 and 17, sample spray, confirm whether the viscosity, NV, color and other properties meet the design requirements, confirm the appearance, color, hiding power and weather resistance of the coating film.

[0087] Preparation method of Comparative Example 3:

[0088] Use a container to prepare Comparative Example 3, first add 6 and 7, disperse evenly, confirm whether the fineness is qualified; add 8 in a fine stream under high-speed stirring, confirm the fineness is qualified, then add 9, 10 and 11 in turn, disperse evenly

[0089] Use another container, add 1 and 2 under stirring, disperse evenly after soaking, confirm whether the fineness is qualified;

[0090] Into the above container, add 11, 12, 13, 14 and 15, disperse uniformly, add 3, 4 and 5 to adjust the color, confirm whether the product fineness is qualified, after qualified, add 16 and 17, take sample and spray, confirm whether the viscosity, NV, color and other properties meet the design requirements, confirm the appearance, color, hiding power and weather resistance of the coating film.

[0091] Since it is applied to the automobile body, each coating is prepared into a composite coating film according to the process shown in Table 3 below, and the results are shown in Table 4.

[0092] Table 3

[0093] Scope of application Automobile body Effect Electroplated effect imitation Substrate Steel Primer Electrodeposition paint First coat of color paint Deep tint color paint Second coat of color paint Metallic paint Clear paint Two-component clear paint

[0094] Table 4: The comparison results of Example 1, Comparative Examples 1, 2 and 3 are as follows

[0095] Item Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Test method Appearance ○ ○ × ○ MES MN601 4 FF property (FI value) 36 20 × 18 MES MN601 6 Hiding power ○ ○ × × GB 1726 Weather resistance ○ ○ × × MES MN601 28

[0096] Note: ○ indicates qualified, and × indicates NG.

[0097] FI value is the metallic feeling index measured by the spectrophotometer of X-Rite Company.

[0098] Conclusion: By adding the aluminum powder directional agent, the coating properties (NV, viscosity), color base ratio adjustment in the automobile body coating system, the color with high FF can be obtained, and the coating film appearance, hiding property and weather resistance and other performances are qualified.

[0099] Example 2

[0100] The specific formula of the application is shown in Table 6 Example 2, and Comparative Examples 5, 6 and 7 are compared, respectively, to confirm the factors such as the type of aluminum powder, the particle size of aluminum particles, and the thickness diameter length of aluminum powder. The specific formula is shown in Table 5.

[0101] Table 5

[0102]

[0103] Aluminum paste 1 is the preferred aluminum powder of the application, which is a non-floating type aluminum silver paste with a particle size D50 of 9 μm, an aluminum powder shape of silver dollar type, and a thickness diameter ratio of 70:1.

[0104] Aluminum paste 2 is a floating type aluminum silver paste with a particle size D50 of 10 μm, an aluminum powder shape of silver dollar type, and a thickness diameter ratio of 70:1.

[0105] Aluminum paste 3 is a non-floating type aluminum silver paste with a particle size D50 of 15 μm, an aluminum powder shape of silver dollar type, and a thickness diameter ratio of 75:1.

[0106] Aluminum paste 4 is a non-floating type aluminum silver paste with a particle size D50 of 9 μm, an aluminum powder shape of silver dollar type, and a thickness diameter ratio of 90:1

[0107] The preparation method of Example 2, Comparative Example 4, Comparative Example 5, Comparative Example 6 is the same as the following coating preparation method:

[0108] Using a container, preparing Example 2 or Comparative Example 4, 5 and 6, first adding 6 and 7, dispersing uniformly, confirming whether the fineness is qualified; adding 8 in a fine stream under high-speed stirring, confirming whether the fineness is qualified, and sequentially adding 9, 10 and 11, dispersing uniformly

[0109] Using another container, adding 1 and 2 under stirring, dispersing uniformly after soaking, and confirming whether the fineness is qualified;

[0110] Adding to the above container, adding 11, 12, 13, 14 and 15, dispersing uniformly, adding 3, 4 and 5 for color matching, confirming whether the product fineness is qualified, and adding 16 and 17 after qualification, confirming the viscosity 11 seconds (Ford-4), NV 10.5%, and performing coating, and the color paint film thickness is 2 μm.

[0111] Since it is applied to the automobile body, the coating needs to be prepared into a composite coating film according to the spraying process and parameter table, and the results are shown in Table 6.

[0112] Table 6: Spraying process and parameters

[0113]

[0114] Table 7: Comparative results of Example 2, Comparative Example 4, 5, 6 are as follows

[0115]

[0116]

[0117] Note: ○ indicates qualified, and × indicates NG;

[0118] Conclusion: By selecting aluminum powder, improving the solid content, viscosity, film thickness of the coating, and the coating process, high FF color can be obtained, and the coating film appearance, adhesion and cycle resistance performance are qualified.

[0119] Example 3

[0120] Since the coating process of the automobile body of the embodiment of the application is changed, the same formula is used for coating according to different processes. The difference between this process and the foregoing process is that the metal paint film thickness is reduced, and the color paste process is changed from two metal paints to plain color paint + metal paint. Among them, the main function of the plain color paint is hiding property and weather resistance, and the main function of the metal paint is to provide high FF color. The prepared coating film is compared in terms of coating film appearance, color, hiding power and weather resistance. The specific formula is shown in Table 8:

[0121] Table 8

[0122]

[0123]

[0124] The preparation method of Example 3, Comparative Example 7, Comparative Example 8, Comparative Example 9 is the same, as follows:

[0125] Using a container, preparing Example 3 or Comparative Example 7, Comparative Example 8, Comparative Example 9, first adding 6 and 7, dispersing evenly, confirming whether the fineness is qualified; adding 8 in a fine stream under high-speed stirring, confirming whether the fineness is qualified, and sequentially adding 9, 10 and 11, dispersing evenly.

[0126] Using another container, adding 1 and 2 under stirring, dispersing evenly after soaking, confirming whether the fineness is qualified;

[0127] Adding to the above container, adding 11, 12, 13, 14 and 15, dispersing evenly, adding 3, 4 and 5 for toning, confirming whether the product fineness is qualified, and after being qualified, adding 16 and 17, taking samples for spraying, confirming whether the viscosity, NV, color and other properties meet the design requirements.

[0128] Table 9: Coating film composition and process

[0129] Example 3 Comparative Example 7 Comparative Example 8 Comparative Example 9 Scope of application Automobile body Automobile body Automobile body Automobile body Substrate Steel Steel Steel Steel Primer Electrodeposition paint Electrodeposition paint Electrodeposition paint Electrodeposition paint Midcoat None None Midcoat None First coat of color paint Deep tint color paint Deep tint color paint Deep tint color paint None Second coat of color paint Metallic paint Metallic paint Metallic paint Metallic paint Clear paint Two-component clear paint Two-component clear paint Two-component clear paint Two-component clear paint

[0130] Table 10: Coating process and parameters

[0131]

[0132] The coating process parameters of each coating process are shown in Table 10, wherein:

[0133] The coating process of Example 3 is as follows:

[0134] On the automobile electrophoresis plate, spray dark color paint 8 μm, stand for 2 minutes, spray the coating film of Example 3 2 μm, stand for 2 minutes, flash dry at 60 degrees for 5 minutes, cool for 5 minutes, spray two-component varnish, stand for 7 minutes, bake at 140 degrees for 30 minutes, confirm the appearance, color, hiding power and weather resistance of the coating film.

[0135] The coating process of Comparative Example 7 is as follows:

[0136] On the automobile electrophoresis plate, spray mid-coat color paint 15 μm, stand for 2 minutes, flash dry at 60 degrees for 5 minutes, spray dark color paint 8 μm, stand for 2 minutes, spray Comparative Example 5 with a thickness of 2 μm, stand for 2 minutes, flash dry at 60 degrees for 5 minutes, cool for 5 minutes, spray two-component varnish, stand for 7 minutes, bake at 140 degrees for 30 minutes, confirm the appearance, color, hiding power and weather resistance of the coating film.

[0137] The coating process of Comparative Example 8 is as follows:

[0138] On the automobile electrophoresis plate, 15 μm of color paint is sprayed, and then it is left for 15 minutes, left for 2 minutes, flash-dried at 60 degrees for 5 minutes, 2 μm of comparative example 6 is sprayed, left for 2 minutes, flash-dried at 60 degrees for 5 minutes, cooled for 5 minutes, two-component varnish is sprayed, left for 7 minutes, baked at 140 degrees for 30 minutes, and the appearance, color, hiding power and weather resistance of the coating film are confirmed.

[0139] The coating process of comparative example 9 is as follows:

[0140] On the automobile electrophoresis plate, 2 μm of comparative example 7 is sprayed, left for 2 minutes, flash-dried at 60 degrees for 5 minutes, cooled for 5 minutes, two-component varnish is sprayed, left for 7 minutes, baked at 140 degrees for 30 minutes, and the appearance, color, hiding power and weather resistance of the coating film are confirmed.

[0141] The comparison results of example 3, comparative example 7, comparative example 8 and comparative example 9 are shown in Table 11 as follows:

[0142] Table 11

[0143] Item Example 3 Comparative Example 7 Comparative Example 8 Comparative Example 9 Test method Appearance ○ ○ ○ ○ MES MN601 4 FF property (FI value) 36 12 18 36 MES MN601 6 Hiding power ○ ○ ○ × GB 1726 Weather resistance ○ ○ ○ × MES MN601 28

[0144] Note: ○ indicates pass, and × indicates NG.

[0145] Conclusion: Through the improvement of the automobile body coating process, the color with high FF can be obtained, and the appearance, hiding property and weather resistance of the coating film are qualified.

[0146] The above implementation scheme has been applied in mass production on automobiles, and the results of automobile production line use confirmation and laboratory are consistent with the expectation, good mirror effect of the automobile body coating film can be provided, and the requirements of continuous production of the automobile body and qualified comprehensive performance are met at the same time.

[0147] Obviously, the above examples of the present application are only examples for clearly illustrating the present application, and are not the limitation to the implementation ways of the present application. For the ordinary skilled in the art, other different forms of changes or variations can be made on the basis of the above description, and it is impossible to enumerate all the implementation ways here. Any changes or variations which belong to the technical scheme of the present application and are derived from the obvious changes or variations still fall within the protection scope of the present application.

Claims

1. Use of a coating composition with electroplated silver effect as a composite coating, characterized in that, the use is achieved by the following steps: spraying a dark base color paint 8 μm on an automobile electrophoresis plate, standing for 2 minutes, spraying the coating composition with electroplated silver effect, coating film thickness 2 μm, standing for 2 minutes, 60 degree flash drying for 5 minutes, cooling for 5 minutes, spraying two-component varnish, standing for 7 minutes, 140 degree baking for 30 minutes, to obtain the composite coating; the coating composition with electroplated silver effect consists of the following components by weight parts: 0.5 to 1.5 parts of aluminum silver paste, 0.1 to 0.6 parts of aluminum powder orientation agent, 2.66 parts of thermosetting acrylic resin, 6.21 parts of amino resin, 2.0 to 8.0 parts of acrylic microgel solution, 4.0 to 8.0 parts of black paste, less than or equal to 5 parts of other color paste by weight parts, 60 to 80 parts of solvent, and 1.0 to 5.0 parts of auxiliary agent; the aluminum silver paste is a non-floating type aluminum silver paste or a silver yuan type aluminum silver paste; the aluminum silver paste has a particle size calculation D50 between 8 μm to 12 μm from small to large; the thickness-diameter ratio of the aluminum silver paste is 60:1 to 80:1; the aluminum powder orientation agent is butyl cellulose acetate; the thermosetting acrylic resin is a resin copolymerized from acrylic monomers; the amino resin is n-butylated melamine formaldehyde resin.

2. Use according to claim 1, characterized in that, The solvent is a mixture of ethyl acetate and aromatic hydrocarbon solvent, and the mass ratio of ethyl acetate to aromatic hydrocarbon solvent is 1-3:6-10.

3. Use according to claim 1, characterized in that, The auxiliary agent contains the following components by weight parts: 0.1 to 0.3 parts of leveling agent, 0.4 to 0.6 parts of resistance regulator, and 0.1 to 0.3 parts of catalyst.

4. Use according to claim 3, characterized in that, The leveling agent is selected from an acid group-containing copolymer solution or a polyether-modified polydimethylsiloxane solution.

5. The use according to claim 3, characterized in that, The resistance regulator is a carboxylic acid ester alcohol ammonium salt solution or methanol.

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