Aluminum powder wrapping liquid for water-based metal finish paint as well as preparation method and application of aluminum powder wrapping liquid

Abstract

The invention discloses aluminum powder wrapping liquid for water-based metal finish paint and a preparation method and application of the aluminum powder wrapping liquid. The raw materials of the aluminum powder wrapping liquid comprise aluminum powder, a solvent, a passivator and amino resin. According to the technical scheme, the brightness of the water-based metal finish paint is effectively improved on the basis that the physical and chemical properties of the paint are not changed.

Description

Technical Field

[0001] This invention relates to the field of waterborne coatings technology. More specifically, it relates to an aluminum powder-coated liquid for waterborne metallic topcoats, its preparation method, and its application. Background Technology

[0002] Water-based metallic topcoats are increasingly widely used in the automotive industry due to their environmental friendliness and color variation depending on the angle of application. Water-based metallic topcoats require high contrast to meet diverse market demands. Existing technologies generally improve the gloss of water-based metallic topcoats using two methods: 1. Improving gloss by reducing the film thickness, but this method can lead to other paint film defects, such as clouding and uneven coloring; 2. Improving aluminum powder orientation by adding magnesium lithium silicate thixotropic agents or polyamide waxes; however, these two additives also have an upper limit to aluminum powder orientation, and once a certain level is reached, the gloss will not increase further.

[0003] Therefore, there is a need to provide a method that can effectively improve the gloss of water-based metallic topcoats without altering the physicochemical properties of the coating itself. Summary of the Invention

[0004] The purpose of this invention is to provide an aluminum powder coating liquid for water-based metallic topcoats, its preparation method, and its application, so as to effectively improve the gloss of water-based metallic topcoats without changing the physicochemical properties of the coating itself.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] On one hand, the present invention provides an aluminum powder coating liquid for water-based metallic topcoat, wherein the raw materials of the aluminum powder coating liquid include aluminum powder, solvent, passivating agent and amino resin.

[0007] Furthermore, in the raw materials of the aluminum powder coating liquid, the mass ratio of the amino resin to the aluminum powder is 0.5-1.5:1.

[0008] Furthermore, the raw materials for the aluminum powder coating liquid are all water-free.

[0009] Furthermore, in the raw materials of the aluminum powder coating liquid, the mass ratio of solvent, amino resin, passivating agent and aluminum powder is 1.4-1.8:0.5-1.5:0.2-0.3:1.

[0010] Furthermore, the raw materials of the aluminum powder coating liquid also contain a wetting and dispersing agent.

[0011] Furthermore, the mass ratio of the wetting and dispersing agent to the aluminum powder is 0.05-0.07:1.

[0012] Furthermore, the raw materials of the aluminum powder coating solution also contain a pH adjuster.

[0013] Furthermore, the mass ratio of the pH adjuster to aluminum powder is 0.01-0.02:1.

[0014] In another aspect, the present invention provides a method for preparing an aluminum powder coating liquid for water-based metallic paint as described above, comprising the following steps:

[0015] After mixing the solvent and amino resin, a passivating agent is added, and after mixing, aluminum powder is added and stirred until the fineness of the aluminum powder is less than 30 μm to obtain the aluminum powder coating liquid for the water-based metallic topcoat.

[0016] In another aspect, the present invention provides a water-based metallic topcoat, which is obtained by mixing raw materials comprising film-forming resin, amino resin, organic solvent, colorant and water with the aluminum powder coating liquid as described above.

[0017] Furthermore, based on parts by weight, the raw materials of the water-based metallic topcoat contain the following components:

[0018] 35-45 parts film-forming resin, 0-4 parts amino resin, 4-10 parts organic solvent, 2-20 parts color paste, 4-16 parts aluminum powder coating solution, and 25-35 parts water.

[0019] In another aspect, the present invention provides a method for preparing the water-based metallic topcoat as described above, characterized by comprising the following steps:

[0020] Under stirring conditions, the raw materials containing film-forming resin, amino resin, organic solvent, colorant and water, and aluminum powder coating liquid are mixed evenly to obtain the water-based metallic topcoat.

[0021] In another aspect, the present invention provides the application of the aluminum powder coating liquid for water-based metallic topcoat as described above in the preparation of water-based metallic topcoat.

[0022] The beneficial effects of this invention are as follows:

[0023] In the technical solution of this invention, by adding an appropriate amount of amino resin to the aluminum powder coating liquid, the brightness of the water-based metallic topcoat can be significantly improved when the aluminum powder coating liquid is used in the water-based metallic topcoat, while ensuring that its physical and chemical properties meet the corresponding requirements. Furthermore, the improved brightness at small angles (15° and 25°) of the water-based metallic topcoat makes it easier for colorists to perform color matching. Detailed Implementation

[0024] 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.

[0025] According to a specific embodiment of the present invention, an aluminum powder coating liquid for water-based metallic topcoat is provided, wherein the raw materials of the aluminum powder coating liquid include aluminum powder, solvent, passivating agent and amino resin.

[0026] In the preparation of water-based metallic topcoats, aluminum powder is typically passivated and coated to reduce its surface chemical reactivity and improve the car's appearance. However, in these methods, the aluminum powder coating solution mainly contains only aluminum powder, solvent, and passivating agent; and the passivated aluminum powder particles are usually directly applied to the water-based metallic topcoat. Under these conditions, it is impossible to impart good gloss to the water-based metallic topcoat without affecting its physicochemical properties. This invention has found that adding amino resin to the aluminum powder coating solution, coating the aluminum powder with the amino resin, and then applying the resulting aluminum powder coating solution to the water-based metallic topcoat can significantly improve the gloss of the water-based aluminum powder topcoat, especially the small-angle gloss (for example, in some examples, it can mainly improve the 15°L value by 5-10 points and the 25°L value by 4-6 points), without affecting its physical and chemical properties.

[0027] In this technical solution, the preferred mass ratio of the amino resin to aluminum powder is 0.5-1.5:1 (i.e., 0.5:1-1.5:1). Within this range, the amino resin can effectively orient the aluminum powder, thereby improving the gloss of the topcoat, especially the gloss at small angles. In some more specific examples, the mass ratio of the amino resin to aluminum powder includes, but is not limited to, 0.5-1.3:1, 0.5-1:1, 1-1.5:1, and 1-1.3:1.

[0028] In this technical solution, the amino resin can be a conventional amino resin used in water-based metallic paint formulations. The amino resin used in this aluminum powder coating liquid is the same as the amino resin used in the water-based metallic paint formulation. The amino resin in this aluminum powder coating liquid can be derived from a portion of the amino resin in the water-based metallic paint formulation. Exemplary amino resins include, but are not limited to, CYMEL 325, CYMEL 250, CYMEL 254, CYMEL 370 selected from Zhanxin Company, or LUWIPAL072, LUWIPAL 069 selected from BASF Company.

[0029] In some examples, the aluminum powder is a commercially available product. This includes, but is not limited to, for example: Toyo Corporation's ALUMINIUM PASTE 93-0647, or Aika Corporation's STAPA IL Hydrolan 2192, STAPA HP Z 2600IL, STAPA HP Z3405IL, STAPA ZP 10861, or Starlink's SFB-9070, etc.

[0030] In some examples, the solvent includes, but is not limited to, one or more selected from ethylene glycol butyl ether, isooctyl alcohol, ethylene glycol isooctyl ether, and n-propanol.

[0031] In some examples, the passivating agent includes, but is not limited to, commercially available products such as Lubrizol 2062H from Lubrizol Corporation or ACS-1212 from Nippon Paint Corporation.

[0032] In this technical solution, the amounts of aluminum powder, solvent, and passivating agent can be the conventional amounts. In some preferred examples, the mass ratio of solvent, amino resin, passivating agent, and aluminum powder in the raw materials of the aluminum powder coating liquid is 1.4-1.8:0.5-1.5:0.2-0.3:1.

[0033] In some examples, the aluminum powder coating liquid also contains a wetting and dispersing agent. The addition of the wetting and dispersing agent can improve the problem of aluminum powder flocculation after circulation, thereby better improving the gloss and appearance of the water-based metallic topcoat. Exemplary wetting and dispersing agents include, but are not limited to, BYK-192, BYK-191, BYK-190, and BYK-180 selected from BYK Corporation, and SURFYNOL 2502 from Air Chemical.

[0034] For example, in the aluminum powder coating liquid, the mass ratio of wetting and dispersing agent to aluminum powder can be 0.05-0.07:1. This can better improve the gloss, mechanical properties, and appearance of the water-based metallic topcoat.

[0035] In some examples, the aluminum powder coating solution also contains a pH adjuster. The pH adjuster may be dimethylethanolamine, etc. In the aluminum powder coating solution, the mass ratio of the pH adjuster to the aluminum powder is 0.01-0.02:1.

[0036] Furthermore, the raw materials for the aluminum powder coating liquid are all anhydrous, in order to avoid the influence of water-containing raw materials on the FI value of water-based metallic topcoats.

[0037] According to another specific embodiment of the present invention, a method for preparing an aluminum powder coating liquid for water-based metallic paint as described above is provided, comprising the following steps:

[0038] After mixing the solvent and amino resin, a passivating agent is added, and after mixing, aluminum powder is added and stirred until the fineness of the aluminum powder is less than 30 μm to obtain the aluminum powder coating liquid for the water-based metallic topcoat.

[0039] In some examples, the preparation method includes the following steps:

[0040] First, add the solvent, amino resin, optional wetting and dispersing agent and / or pH adjuster into a suitable container. Stir at a speed of 500-700 r / min for 10-15 min, then add the passivating agent and continue stirring for 10-15 min. Then add aluminum powder and stir until the fineness is less than 30 microns.

[0041] It should be noted that the above "optional existence" includes both the presence and absence of wetting and dispersing agents and / or pH adjusters. When there are no wetting and dispersing agents and / or pH adjusters in the raw materials, there is naturally no need to add wetting and dispersing agents and / or pH adjusters.

[0042] According to another specific embodiment of the present invention, a water-based metallic topcoat is provided, which is obtained by mixing raw materials comprising film-forming resin, amino resin, organic solvent, colorant and water with an aluminum powder coating liquid as described above.

[0043] In this embodiment, the water-based metallic topcoat is preferably a water-based metallic topcoat for automotive painting. This water-based metallic topcoat includes, but is not limited to, water-based acrylic systems, water-based polyester-amino systems, or water-based polyurethane systems.

[0044] In some examples, the mass ratio of amino resin in the raw material to amino resin in the aluminum powder coating solution is 1:0.1-1:5. Here, amino resin in the raw material refers to amino resin used other than that in the aluminum powder coating solution. In this case, while significantly improving the gloss of the water-based metallic topcoat, its physicochemical properties are ensured to meet the corresponding requirements. In further specific examples, the mass ratio is 1:0.5-1:4, 1:0.5-1:2, 1:2-1:4, 1:0.5, 1:2, 1:4, etc.

[0045] In some examples, the raw materials of the water-based metallic topcoat, by weight, contain the following components:

[0046] 35-45 parts film-forming resin, 0-4 parts amino resin, 4-10 parts organic solvent, 2-20 parts color paste, 4-16 parts aluminum powder coating solution, and 25-35 parts water.

[0047] In some examples, in this embodiment, the amount of each component in the raw materials of the water-based metallic topcoat is 100 parts by weight relative to the total mass of the raw materials.

[0048] In some other examples, the raw materials of the water-based metallic topcoat, by weight, contain the following components:

[0049] 38.6 parts film-forming resin, 2 parts amino resin, 9.1 parts organic solvent, 4.01 parts color paste, 13.35 parts aluminum powder coating solution and 19.04 parts water.

[0050] It should be noted that in the water-based metallic topcoat of this embodiment, the raw materials such as film-forming resin, amino resin, organic solvent, and color paste can all be the same raw materials used in conventional water-based metallic topcoats, and will not be elaborated here.

[0051] For example, in some examples, the film-forming resin may include a polyurethane emulsion (e.g. One or more of the following: TW 6464 / 36WA, polyester resin (e.g., SETAQUA 6407), acrylic emulsion (e.g., Setaqua 6802).

[0052] In some examples, the organic solvent includes, but is not limited to, one or more selected from isooctanol, ethylene glycol butyl ether, and high-boiling-point hydrocarbon solvents (such as BYK-WA, EXXSOL D40, etc.). It is understood that in this embodiment, additives may also be added to the raw materials of the water-based metallic topcoat as needed. Exemplary additives include, but are not limited to, alkali thickeners (such as Viscalex HV 30, etc.), defoamers (such as BYK-015, etc.), surfactants (such as SURFYNOL 104PG-50, etc.), polyamide waxes (such as DISPARLON AQ-021, etc.), pearlescent agents (such as blue pearlescent agents (such as AK-781C-OP, etc.), white pearlescent agents (such as AK-909K-OP, etc.)), pH adjusters (such as 10% dimethylethanolamine aqueous solution, etc.), and inorganic salt rheology modifiers (such as RD aqueous solution, etc.).

[0053] According to another specific embodiment of the present invention, a method for preparing the water-based metallic topcoat as described above is provided, the method comprising the following steps:

[0054] Under stirring conditions, the raw materials containing film-forming resin, amino resin, organic solvent, colorant and water, and aluminum powder coating liquid are mixed evenly to obtain the water-based metallic topcoat.

[0055] According to another specific embodiment of the present invention, the application of the aluminum powder encapsulation liquid for water-based metallic topcoat as described above in the preparation of water-based metallic topcoat is provided.

[0056] The technical solution of the present invention will be described below with reference to some specific embodiments:

[0057] Example 1

[0058] A method for preparing a water-based metallic topcoat includes the following steps:

[0059] 1) Preparation of aluminum powder coating solution:

[0060] According to the raw material ratio in the premixing stage in Table 1, first add the solvent, amino resin, wetting and dispersing agent, and pH adjuster into a suitable container, stir for 10 minutes at a speed of 500-700 r / min, then add the passivating agent, continue stirring for 10 minutes, and then add aluminum powder and stir until the fineness is less than 30 microns for later use.

[0061] 2) Preparation of topcoat:

[0062] According to the raw material ratio in the paint preparation stage in Table 1, polyurethane emulsion, RD aqueous solution, polyester resin, amino resin, acrylic emulsion, alkali thickener, solvent, defoamer, surfactant, polyamide wax, pearl powder, color paste, aluminum powder coating liquid from step 1), pH adjuster, and water are added in sequence under stirring conditions to prepare the water-based metallic topcoat.

[0063] Table 1

[0064]

[0065] Example 2

[0066] A method for preparing a water-based metallic topcoat includes the following steps:

[0067] 1) Preparation of aluminum powder coating solution:

[0068] According to the raw material ratio in the premixing stage in Table 2, first add the solvent, amino resin, wetting and dispersing agent, and pH adjuster into a suitable container, stir for 10 minutes at a speed of 500-700 r / min, then add the passivating agent, continue stirring for 10 minutes, and then add aluminum powder and stir until the fineness is less than 30 microns for later use.

[0069] 2) Preparation of topcoat:

[0070] According to the raw material ratio in the paint preparation stage in Table 2, polyurethane emulsion, RD aqueous solution, polyester resin, amino resin, acrylic emulsion, alkali thickener, solvent, defoamer, surfactant, polyamide wax, pearl powder, color paste, aluminum powder coating liquid in step 1), pH adjuster, and water are added in sequence under stirring conditions to prepare the water-based metallic topcoat.

[0071] Table 2

[0072]

[0073] Example 3

[0074] A method for preparing a water-based metallic topcoat includes the following steps:

[0075] 1) Preparation of aluminum powder coating solution:

[0076] According to the raw material ratio in the premixing stage in Table 3, first add the solvent, amino resin, wetting and dispersing agent, and pH adjuster into a suitable container, stir for 10 minutes at a speed of 500-700 r / min, then add the passivating agent, continue stirring for 10 minutes, and then add aluminum powder and stir until the fineness is less than 30 microns for later use.

[0077] 2) Preparation of topcoat:

[0078] According to the raw material ratio in the paint preparation stage in Table 3, polyurethane emulsion, RD aqueous solution, polyester resin, amino resin, acrylic emulsion, alkali thickener, solvent, defoamer, surfactant, polyamide wax, pearl powder, color paste, aluminum powder coating liquid in step 1), pH adjuster, and water are added in sequence under stirring conditions to prepare the water-based metallic topcoat.

[0079] Table 3

[0080]

[0081]

[0082] Example 4

[0083] A method for preparing a water-based metallic topcoat includes the following steps:

[0084] 1) Preparation of aluminum powder coating solution:

[0085] According to the raw material ratio in the premixing stage in Table 4, first add the solvent, amino resin, wetting and dispersing agent, and pH adjuster into a suitable container, stir for 10 minutes at a speed of 500-700 r / min, then add the passivating agent, continue stirring for 10 minutes, and then add aluminum powder and stir until the fineness is less than 30 microns for later use.

[0086] 2) Preparation of topcoat:

[0087] According to the raw material ratio in the paint preparation stage in Table 4, polyurethane emulsion, RD aqueous solution, polyester resin, amino resin, acrylic emulsion, alkali thickener, solvent, defoamer, surfactant, polyamide wax, pearl powder, color paste, aluminum powder coating liquid in step 1), pH adjuster, and water are added in sequence under stirring conditions to prepare the water-based metallic topcoat.

[0088] Table 4

[0089]

[0090]

[0091] Comparative Example 1

[0092] A method for preparing a water-based metallic topcoat includes the following steps:

[0093] 1) Preparation of aluminum powder coating solution:

[0094] According to the raw material ratio in the premixing stage in Table 5, first add the solvent, polyester resin, and pH adjuster into a suitable container, stir for 10 minutes at a speed of 500-700 r / min, then add the passivating agent, continue stirring for 10 minutes, and then add aluminum powder and stir until the fineness is less than 30 microns for later use.

[0095] 2) Preparation of topcoat:

[0096] According to the raw material ratio in the paint preparation stage in Table 5, polyurethane emulsion, RD aqueous solution, amino resin, acrylic emulsion, alkali thickener, solvent, wetting and dispersing agent, defoamer, surfactant, polyamide wax, pearl powder, color paste, aluminum powder coating liquid in step 1), pH adjuster, and water are added in sequence under stirring conditions to prepare the water-based metallic topcoat.

[0097] Table 5

[0098]

[0099]

[0100] Comparative Example 2

[0101] A method for preparing a water-based metallic topcoat includes the following steps:

[0102] 1) Preparation of aluminum powder coating solution:

[0103] According to the raw material ratio in the premixing stage in Table 6, first add the solvent and pH adjuster into a suitable container, stir for 10 minutes at a speed of 500-700 r / min, then add the passivating agent, continue stirring for 10 minutes, then add aluminum powder and stir until the fineness is less than 30 microns for later use.

[0104] 2) Preparation of topcoat:

[0105] According to the raw material ratio in the paint preparation stage in Table 6, polyurethane emulsion, RD aqueous solution, polyester resin, amino resin, acrylic emulsion, alkali thickener, solvent, wetting and dispersing agent, defoamer, surfactant, polyamide wax, pearl powder, color paste, aluminum powder coating liquid from step 1), pH adjuster, and water are added sequentially under stirring conditions to prepare the water-based metallic topcoat.

[0106] Table 6

[0107]

[0108]

[0109] Comparative Example 3

[0110] A method for preparing a water-based metallic topcoat includes the following steps:

[0111] 1) Preparation of aluminum powder coating solution:

[0112] According to the raw material ratio in the premixing stage in Table 7, first add the solvent, wetting and dispersing agent, pH adjuster to a suitable container, stir for 10 minutes at a speed of 500-700 r / min, then add the passivating agent, continue stirring for 10 minutes, then add aluminum powder and stir until the fineness is less than 30 microns for later use.

[0113] 2) Preparation of topcoat:

[0114] According to the raw material ratio in the paint preparation stage in Table 7, polyurethane emulsion, RD aqueous solution, polyester resin, amino resin, acrylic emulsion, alkali thickener, solvent, defoamer, surfactant, polyamide wax, pearl powder, color paste, aluminum powder coating liquid in step 1), pH adjuster, and water are added in sequence under stirring conditions to prepare the water-based metallic topcoat.

[0115] Table 7

[0116]

[0117]

[0118] Comparative Example 4

[0119] A method for preparing a water-based metallic topcoat includes the following steps:

[0120] 1) Preparation of aluminum powder coating solution:

[0121] According to the raw material ratio in the premixing stage in Table 8, first add the solvent, wetting and dispersing agent, pH adjuster to a suitable container, stir for 10 minutes at a speed of 500-700 r / min, then add the passivating agent, continue stirring for 10 minutes, then add aluminum powder and stir until the fineness is less than 30 microns for later use.

[0122] 2) Preparation of topcoat:

[0123] According to the raw material ratio in the paint preparation stage in Table 8, polyurethane emulsion, RD aqueous solution, polyester resin, amino resin, acrylic emulsion, alkali thickener, solvent, defoamer, surfactant, polyamide wax, pearl powder, color paste, aluminum powder coating liquid in step 1), pH adjuster, and water are added in sequence under stirring conditions to prepare the water-based metallic topcoat.

[0124] Table 8

[0125]

[0126]

[0127] Performance testing:

[0128] Preparation of composite coatings:

[0129] The composite coating consists of: electrophoresis + 3C1B1PH intermediate coating + topcoat prepared in the above examples or comparative examples + 2K CC; wherein, the 3C1B1PH intermediate coating has a film thickness of 10-12 micrometers;

[0130] The topcoat film thickness prepared in the examples or comparative examples is 17-19 micrometers;

[0131] The 2K CC film is 50-55 micrometers thick.

[0132] The composite coating was prepared by robotic spraying, and the specific process parameters are shown in Table 9 below.

[0133] Table 9

[0134]

[0135]

[0136] The performance of the obtained composite coating is shown in Tables 10 and 11 below:

[0137] Table 10

[0138]

[0139]

[0140] Table 11

[0141]

[0142]

[0143] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A water-based metal topcoat aluminum powder coating liquid, characterized in that: The raw materials of the aluminum powder coating liquid include aluminum powder, solvent, passivator and amino resin.

2. The aluminum powder coating liquid for water-based metallic topcoat according to claim 1, characterized in that: In the raw materials of the aluminum powder coating liquid, the mass ratio of the amino resin to the aluminum powder is 0.5-1.5:

1.

3. The aluminum powder coating liquid for water-based metal topcoat according to claim 1, characterized in that: The raw materials of the aluminum powder coating liquid are all water-free raw materials; and / or In the raw materials of the aluminum powder coating liquid, the mass ratio of the solvent, the amino resin, the passivator and the aluminum powder is 1.4-1.8:0.5-1.5:0.2-0.3:

1.

4. The aluminum powder coating liquid for water-based metal topcoat according to claim 3, characterized in that: The raw materials of the aluminum powder coating liquid further include a wetting and dispersing agent; and / or The mass ratio of the wetting and dispersing agent to the aluminum powder is 0.05-0.07:

1.

5. The aluminum powder coating liquid for water-based metal topcoat according to claim 3, characterized in that: The raw materials of the aluminum powder coating liquid further include a pH regulator; and / or The mass ratio of the pH regulator to the aluminum powder is 0.01-0.02:

1.

6. The method for preparing the aluminum powder coating liquid for water-based metallic topcoat according to any one of claims 1 to 5, characterized in that: The steps include: After the solvent and the amino resin are mixed evenly, a passivator is added, and after mixing evenly, aluminum powder is added and stirred until the fineness of the aluminum powder is less than 30 μm to obtain the aluminum powder coating liquid for the water-based metal topcoat.

7. A water-based metallic topcoat, characterized in that: The water-based metal topcoat is obtained by mixing raw materials including a film-forming resin, an amino resin, an organic solvent, a color paste and water with the aluminum powder coating liquid as described in any one of claims 1 to 5.

8. The water-based metallic topcoat according to claim 7, characterized in that: The raw materials of the water-based metallic topcoat include the following components by mass: 35-45 parts of film-forming resin, 0-4 parts of amino resin, 4-10 parts of organic solvent, 2-20 parts of color paste, 4-16 parts of aluminum powder coating liquid and 25-35 parts of water.

9. A method for preparing a water-based metallic topcoat as claimed in any one of claims 7 to 8, characterized in that: The steps include: Under stirring conditions, raw materials including film-forming resin, amino resin, organic solvent, color paste and water, and aluminum powder coating liquid are mixed to obtain the water-based metal topcoat.

10. Use of the aluminum powder coating liquid for water-based metallic topcoat according to any one of claims 1 to 5 in the preparation of water-based metallic topcoat.

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