Electroplating paint and application thereof

Abstract

The invention belongs to the field of electroplating paint, and particularly relates to electroplating paint and application thereof. The electroplating coating paint provided by the invention is prepared from the following components in percentage by mass: 50 to 70 percent of acrylic resin, 5 to 15 percent of amino resin, 0.5 to 3 percent of adhesion promoter, 0.1 to 1 percent of drier, 6 to 20 percent of ethylene glycol butyl ether, 0.5 to 3.5 percent of flatting agent and 3 to 15 percent of n-butyl alcohol. According to the invention, the component formula of the electroplating coating paint is optimally designed, so that the binding force of a paint film and UV ink is improved under the condition that the appearance of the paint film is not influenced, and the toughness, wear resistance, impact resistance, scratch resistance and corrosion resistance of the paint film are improved.

Description

Technical Field

[0001] The invention belongs to the field of electroplating paint, and in particular relates to an electroplating paint and an application thereof. Background Art

[0002] The puller is an important part of clothing accessories. In order to unify the overall appearance of clothing, the shape and appearance of the accessories on the clothing are also designed and produced in accordance with the current fashion trends. At present, many customers require electroplated pullers to be colorful. The puller is electroplated first, and then UV printed on it. It can be multi-colored or in a raised shape, which has a large market demand.

[0003] At present, most of the coatings sprayed on the surface of electroplated parts in the market are acrylic resin coatings. This coating has excellent performance, good light resistance, weather resistance, heat resistance, over-baking resistance, chemical resistance and corrosion resistance, and can be dissolved in a variety of solvents. The cured product has high strength and bonding strength, high corrosion resistance and electrical properties, and certain toughness and heat resistance. However, this type of coating has the disadvantages of low heat resistance and toughness, poor moisture and heat resistance and weather resistance, low bonding with UV ink, and corrosion in salt spray tests, which cannot meet customer needs. Summary of the invention

[0004] In view of this, the object of the present invention is to provide an electroplating paint and its application. The electroplating paint provided by the present invention has high bonding strength with UV ink and has good toughness, wear resistance, impact resistance, scratch resistance and corrosion resistance.

[0005] The present invention provides an electroplating paint, which comprises the following components in percentage by mass:

[0006]

[0007]

[0008] Preferably, the following components are included in percentage by mass:

[0009]

[0010] The present invention provides a surface treatment method for an electroplated part, comprising the following steps:

[0011] a) spraying and baking on the surface of the electroplated part to obtain a first semi-finished product;

[0012] In step a), the sprayed coating composition includes the electroplating coating paint described in the above technical solution;

[0013] b) performing UV printing on the surface of the first semi-finished product to obtain a second semi-finished product;

[0014] c) spraying and baking again on the surface of the second semi-finished product to obtain a finished product;

[0015] In step c), the coating component sprayed again includes the electroplating coating paint described in the above technical solution.

[0016] Preferably, in step a), the electroplated part is prepared according to the following steps: the blank is subjected to sulfurization treatment, drying and electroplating in sequence to obtain the electroplated part.

[0017] Preferably, in step a), the sprayed coating composition includes the electroplating coating paint, a diluent and ethylene glycol monobutyl ether.

[0018] Preferably, the mass ratio of the electroplating paint, the diluent and ethylene glycol monobutyl ether is 10:(5-15):(0.5-2).

[0019] Preferably, in step c), the re-sprayed coating composition includes the electroplating coating paint and a thinner; and the finished product is a matte finished product.

[0020] Preferably, the mass ratio of the electroplating paint to the diluent is 10:(5-15).

[0021] Preferably, in step c), the coating composition for re-spraying includes the electroplating coating paint, n-pentyl acetate, a diluent and ethylene glycol monobutyl ether; and the finished product is a bright surface finished product.

[0022] Preferably, the mass ratio of the electroplating paint, n-pentyl acetate, diluent and ethylene glycol monobutyl ether is 10:(0.05-0.2):(5-15):(0.5-2).

[0023] Compared with the prior art, the present invention provides an electroplating paint and its application. In terms of mass percentage, the electroplating paint provided by the present invention includes the following components: 50-70% acrylic resin, 5-15% amino resin, 0.5-3% adhesion promoter, 0.1-1% drying agent, 6-20% ethylene glycol butyl ether, 0.5-3.5% leveling agent, and 3-15% n-butanol. The present invention optimizes the composition formula of the electroplating paint, improves the bonding force between the paint film and UV ink without affecting the appearance of the paint film, and improves the toughness, wear resistance, impact resistance, scratch resistance and corrosion resistance of the paint film. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0025] Figure 1 This is a physical picture of the finished slider provided in Example 1 of the present invention;

[0026] Figure 2 This is a physical picture of the finished slider provided in Example 2 of the present invention;

[0027] Figure 3 This is a physical picture of the finished slider provided in Comparative Example 1 of the present invention;

[0028] Figure 4 This is a physical picture of the finished slider provided in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The present invention provides an electroplating paint, which comprises the following components in percentage by mass:

[0031]

[0032]

[0033] In the electroplating paint provided by the present invention, the acrylic resin is preferably an acrylic resin with a brand name of FG67-1878 produced by China Paint; the mass content of the acrylic resin in the electroplating paint can specifically be 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69 or 70%.

[0034] In the electroplating paint provided by the present invention, the amino resin is preferably an amino resin with the brand Luwipal 052 produced by BASF of Germany; the mass content of the amino resin in the electroplating paint can specifically be 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5% or 15%.

[0035] In the electroplating paint provided by the present invention, the adhesion promoter is preferably an adhesion promoter with a brand name of LTH produced by Germany's Digo; the mass content of the adhesion promoter in the electroplating paint can specifically be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9% or 3%.

[0036] In the electroplating paint provided by the present invention, the drying agent is preferably a drying agent with the brand name MOK-7011 produced by Merck, Germany; the mass content of the drying agent in the electroplating paint can specifically be 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95% or 1%.

[0037] In the electroplating paint provided by the present invention, the mass content of the ethylene glycol butyl ether in the electroplating paint can be specifically 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%.

[0038] In the electroplating paint provided by the present invention, the leveling agent is preferably a leveling agent with a brand name BYK-310 produced by BYK of Germany; the mass content of the leveling agent in the electroplating paint can specifically be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, 3.1%, 3.2%, 3.3%, 3.4% or 3.5%.

[0039] In the electroplating paint provided by the present invention, the mass content of n-butanol in the electroplating paint can be 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5% or 15%.

[0040] The present invention also provides a surface treatment method for an electroplated part, comprising the following steps:

[0041] a) spraying and baking on the surface of the electroplated part to obtain a first semi-finished product;

[0042] In step a), the sprayed coating composition includes the electroplating coating paint described in the above technical solution;

[0043] b) performing UV printing on the surface of the first semi-finished product to obtain a second semi-finished product;

[0044] c) spraying and baking again on the surface of the second semi-finished product to obtain a finished product;

[0045] In step c), the coating component sprayed again includes the electroplating coating paint described in the above technical solution.

[0046] In the surface treatment method provided by the present invention, in step a), the electroplated part is preferably a slider electroplated part; the electroplated part is prepared according to the following steps:

[0047] The rough parts are successively subjected to vulcanization treatment, drying and electroplating to obtain electroplated parts.

[0048] In the above-mentioned electroplating parts preparation steps provided by the present invention, the specific process of the vulcanization treatment preferably includes: immersing the blank in an aqueous solution of a vulcanizing agent for vulcanization treatment; wherein the immersion temperature is preferably 30 to 50°C, specifically 30°C, 35°C, 40°C, 45°C or 50°C; the immersion time is preferably 5 to 6 minutes.

[0049] In the above-mentioned electroplating parts preparation steps provided by the present invention, the drying method is preferably to perform spin drying and drying in sequence; wherein, the spin drying time is preferably 5 to 10 minutes; the drying temperature is preferably 100 to 120°C, specifically 100°C, 105°C, 110°C, 115°C or 120°C; the drying time is preferably 60 to 80 minutes.

[0050] In the above-mentioned electroplating parts preparation steps provided by the present invention, the electroplating temperature is preferably 25-70°C, specifically 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C or 70°C; the electroplating time is preferably 60-80min, specifically 60min, 65min, 70min, 75min or 80min.

[0051] In the surface treatment method provided by the present invention, in step a), the sprayed coating component preferably includes the electroplating coating paint, a thinner and ethylene glycol monobutyl ether; wherein the thinner is preferably an antistatic thinner and / or an ordinary thinner, and the mass ratio of the antistatic thinner to the ordinary thinner is preferably 6:(1-5), more preferably 6:3; the mass ratio of the electroplating coating paint, the thinner and ethylene glycol monobutyl ether is preferably 10:(5-15):(0.5-2), more preferably 10:9:1.

[0052] In the surface treatment method provided by the present invention, in step a), the air pressure of the spray gun is preferably 0.4-0.6 MPa, specifically 0.4 MPa, 0.45 MPa, 0.5 MPa, 0.55 MPa or 0.6 MPa; the spraying method is preferably electrostatic spraying, and the electrostatic voltage is preferably 40-60 kV, specifically 40 kV, 45 kV, 50 kV, 55 kV or 60 kV.

[0053] In the surface treatment method provided by the present invention, in step a), the baking time is preferably 60-90°C, specifically 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C; the baking time is preferably 90-120min, specifically 90min, 95min, 100min, 105min, 110min, 115min or 120min.

[0054] In the surface treatment method provided by the present invention, in step c), a matte finished product or a glossy finished product can be obtained by adjusting the composition of the coating to be sprayed again. Specifically:

[0055] When the re-sprayed coating composition preferably includes the electroplating paint and a thinner, the resulting finished product is a matte finished product. The thinner is preferably an antistatic thinner and / or a common thinner, and the mass ratio of the antistatic thinner to the common thinner is preferably 6:(1-5), more preferably 6:3; the mass ratio of the electroplating paint to the thinner is preferably 10:(5-15), more preferably 10:9.

[0056] When the re-sprayed coating composition preferably includes the electroplating coating paint, n-pentyl acetate, diluent and ethylene glycol monobutyl ether, the obtained finished product is a bright finished product. Among them, the diluent is preferably an antistatic diluent and / or a common diluent, and the mass ratio of the antistatic diluent to the common diluent is preferably 5:(1-5), more preferably 5:3; the mass ratio of the electroplating coating paint, n-pentyl acetate, diluent and ethylene glycol monobutyl ether is preferably 10:(0.05-0.2):(5-15):(0.5-2), more preferably 10:0.1:8:1.

[0057] In the surface treatment method provided by the present invention, in step c), the air pressure of the spray gun for the second spraying is preferably 0.4-0.6 MPa, specifically 0.4 MPa, 0.45 MPa, 0.5 MPa, 0.55 MPa or 0.6 MPa; the second spraying method is preferably electrostatic spraying, and the electrostatic voltage is preferably 40-60 kV, specifically 40 kV, 45 kV, 50 kV, 55 kV or 60 kV.

[0058] In the surface treatment method provided by the present invention, in step c), the baking time is preferably 110-140°C, specifically 110°C, 115°C, 120°C, 125°C, 130°C, 135°C or 140°C; the baking time is preferably 45-60min, specifically 45min, 50min or 60min.

[0059] The technical solution provided by the present invention optimizes the composition formula of the electroplating paint, thereby improving the bonding strength between the paint film and UV ink without affecting the appearance of the paint film, and improving the toughness, wear resistance, impact resistance, scratch resistance and corrosion resistance of the paint film.

[0060] For the purpose of greater clarity, the present invention is described in detail with reference to the following examples and comparative examples.

[0061] In the following embodiments and comparative examples of the present invention, the acrylic resin used is an acrylic resin with a brand name of FG67-1878 produced by China Paint, the amino resin used is an amino resin with a brand name of Luwipal 052 produced by BASF of Germany, the adhesion promoter used is an adhesion promoter with a brand name of LTH produced by Digo of Germany, the drying agent used is a drying agent with a brand name of MOK-7011 produced by Merck of Germany, and the leveling agent used is a leveling agent with a brand name of BYK-310 produced by BYK of Germany.

[0062] Example 1

[0063] (I) In terms of mass percentage, the formula ingredients of electroplating paint are:

[0064]

[0065] (II) The surface treatment method of the slider is as follows:

[0066] (1) The slider blank made of zinc alloy is immersed in a vulcanizing agent solution (5 wt % dilute sulfuric acid) for vulcanization treatment at a temperature of 40° C. for 5 min;

[0067] (2) placing the vulcanized slider blank in a spin dryer for 10 minutes, and then placing it in a drying tunnel and drying it at 120° C. for 60 minutes;

[0068] (3) The dried slider is mounted on a hanger for electroplating at a temperature of 35° C., a voltage of 4±2.5 V, a current of 110±20 A, and a time of 60 min;

[0069] (4) The slider electroplating parts are subjected to the first spraying and baking; wherein the coating composition of the first spraying includes the above-mentioned electroplating coating paint, antistatic thinner (Zhonghua Paint 205), ordinary thinner (Zhonghua Paint 9900-1402) and ethylene glycol monobutyl ether (mass ratio is 10:6:3:1), and the coating concentration is controlled at 8 to 11 seconds in summer (May to October) and 10 to 13 seconds in winter (November to April) using Iwata No. 4 viscosity cup test; the spraying method is electrostatic spraying, the spray gun air pressure is controlled at 0.5 MPa, and the electrostatic voltage is controlled at 50 kV; the baking temperature is 70°C, and the baking time is 100 min;

[0070] (5) Place the slider that has completed the first spraying and baking on the UV printer for UV printing. The UV printing ink used is MIMKI LH100 UV ink, the printing temperature is 35-40°C, and the printing time is 6.5 minutes;

[0071] (6) spraying and baking the UV-printed slider for the second time; wherein the coating composition of the second spraying includes the electroplating paint, antistatic diluent and ordinary diluent (mass ratio is 10:6:3); the spraying method is electrostatic spraying, the spray gun air pressure is controlled at 0.5MPa, and the electrostatic voltage is controlled at 50kV; the baking temperature is 120°C, and the baking time is 50min;

[0072] (7) The slider that has been sprayed and baked for the second time is cooled to obtain a matte slider finished product (such as Figure 1 shown).

[0073] Example 2

[0074] (I) In terms of mass percentage, the formula ingredients of electroplating paint are:

[0075]

[0076] (II) The surface treatment method of the slider is as follows:

[0077] (1) The slider blank made of zinc alloy is immersed in a vulcanizing agent solution (5 wt % dilute sulfuric acid) for vulcanization treatment at a temperature of 40° C. for 5 min;

[0078] (2) placing the vulcanized slider blank in a spin dryer for 10 minutes, and then placing it in a drying tunnel and drying it at 120° C. for 60 minutes;

[0079] (3) The dried slider is mounted on a hanger for electroplating at a temperature of 35° C., a voltage of 4±2.5 V, a current of 110±20 A, and a time of 60 min;

[0080] (4) The slider electroplating parts are subjected to the first spraying and baking; wherein the coating composition of the first spraying includes the above-mentioned electroplating coating paint, antistatic thinner (Zhonghua Paint 205), ordinary thinner (Zhonghua Paint 9900-1402) and ethylene glycol monobutyl ether (mass ratio is 10:6:3:1), and the coating concentration is controlled at 8 to 13 seconds (5 to 30°C) using Iwata No. 4 viscosity cup test; the spraying method is electrostatic spraying, the spray gun air pressure is controlled at 0.5MPa, and the electrostatic voltage is controlled at 50kV; the baking temperature is 70°C, and the baking time is 100min;

[0081] (5) Place the slider that has completed the first spraying and baking on the UV printer for UV printing. The UV printing ink used is MIMKI LH100 UV ink, the printing temperature is 35-40°C, and the printing time is 6.5 minutes;

[0082] (6) spraying and baking the UV-printed slider for the second time; wherein the coating composition of the second spraying includes the above-mentioned electroplating paint, n-pentyl acetate, antistatic diluent, ordinary diluent, and ethylene glycol monobutyl ether (mass ratio is 10:0.1:5:3:1); the spraying method is electrostatic spraying, the spray gun air pressure is controlled at 0.5MPa, and the electrostatic voltage is controlled at 50kV; the baking temperature is 120°C, and the baking time is 50min;

[0083] (7) The slider that has been sprayed and baked for the second time is cooled to obtain a finished bright slider (such as Figure 2 shown).

[0084] Comparative Example 1

[0085] (I) In terms of mass percentage, the formula ingredients of electroplating paint are:

[0086]

[0087] (II) The surface treatment method of the slider is as follows:

[0088] (1) The slider blank made of zinc alloy is immersed in a vulcanizing agent solution (5 wt % dilute sulfuric acid) for vulcanization treatment at a temperature of 40° C. for 5 min;

[0089] (2) placing the vulcanized slider blank in a spin dryer for 10 minutes, and then placing it in a drying tunnel and drying it at 120° C. for 60 minutes;

[0090] (3) The dried slider is mounted on a hanger for electroplating at a temperature of 35° C., a voltage of 4±2.5 V, a current of 110±20 A, and a time of 60 min;

[0091] (4) The electroplated slider is subjected to the first spraying and baking; wherein the coating composition of the first spraying includes the above-mentioned electroplating coating paint, antistatic thinner (Zhonghua Paint 205), ordinary thinner (Zhonghua Paint 9900-1402) and ethylene glycol monobutyl ether (mass ratio is 9:5:5:2), and the coating concentration is controlled at 8 to 13 seconds (temperature 5 to 30°C) using Iwata No. 4 viscosity cup test; the spraying method is electrostatic spraying, the spray gun air pressure is controlled at 0.5MPa, and the electrostatic voltage is controlled at 50kV; the baking temperature is 70°C, and the baking time is 100min;

[0092] (5) Place the slider that has completed the first spraying and baking on the UV printer for UV printing. The UV printing ink used is MIMKI LH100 UV ink, the printing temperature is 35-40°C, and the printing time is 6.5 minutes;

[0093] (6) spraying and baking the UV-printed slider for the second time; wherein the coating composition of the second spraying includes the electroplating paint, antistatic diluent and ordinary diluent (mass ratio is 9:5:5); the spraying method is electrostatic spraying, the spray gun air pressure is controlled at 0.5MPa, and the electrostatic voltage is controlled at 50kV; the baking temperature is 120°C, and the baking time is 50min;

[0094] (7) The slider that has been sprayed and baked for the second time is cooled to obtain a matte slider finished product (such as Figure 3 shown).

[0095] Comparative Example 2

[0096] (I) In terms of mass percentage, the formula ingredients of electroplating paint are:

[0097]

[0098] (II) The surface treatment method of the slider is as follows:

[0099] (1) The slider blank made of zinc alloy is immersed in a vulcanizing agent solution (5 wt % dilute sulfuric acid) for vulcanization treatment at a temperature of 40° C. for 5 min;

[0100] (2) placing the vulcanized slider blank in a spin dryer for 10 minutes, and then placing it in a drying tunnel and drying it at 120° C. for 60 minutes;

[0101] (3) The dried slider is mounted on a hanger for electroplating at a temperature of 35° C., a voltage of 4±2.5 V, a current of 110±20 A, and a time of 60 min;

[0102] (4) The slider electroplating parts are subjected to the first spraying and baking; wherein the coating composition of the first spraying includes the above-mentioned electroplating paint, antistatic thinner (Zhonghua Paint 205), ordinary thinner (Zhonghua Paint 9900-1402) and ethylene glycol monobutyl ether (mass ratio is 9:5:5:2), and the coating concentration is controlled at 8 to 13 seconds (5 to 30°C) using Iwata No. 4 viscosity cup test; the spraying method is electrostatic spraying, the spray gun air pressure is controlled at 0.5MPa, and the electrostatic voltage is controlled at 50kV; the baking temperature is 70°C, and the baking time is 100min;

[0103] (5) Place the slider that has completed the first spraying and baking on the UV printer for UV printing. The UV printing ink used is MIMKI LH100 UV ink, the printing temperature is 35-40°C, and the printing time is 6.5 minutes;

[0104] (6) spraying and baking the UV-printed slider for the second time; wherein the coating composition of the second spraying includes the above-mentioned electroplating paint, n-pentyl acetate, antistatic diluent, ordinary diluent, and ethylene glycol monobutyl ether (mass ratio is 9:0.5:4:4:2); the spraying method is electrostatic spraying, the spray gun air pressure is controlled at 0.5MPa, and the electrostatic voltage is controlled at 50kV; the baking temperature is 120°C, and the baking time is 50min;

[0105] (7) The slider that has been sprayed and baked for the second time is cooled to obtain a finished bright slider (such as Figure 4 shown).

[0106] Performance Testing

[0107] The finished sliders prepared in Examples 1 to 2 and Comparative Examples 1 to 2 were subjected to water washing and salt spray tests, and the test conditions and results are as follows:

[0108]

[0109] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An electroplating paint, characterized in that: Calculated by mass percentage, it includes the following components:

2. The electroplating paint according to claim 1, characterized in that: Calculated by mass percentage, it includes the following components:

3. A surface treatment method for electroplated parts, characterized in that: The following steps are involved: a) spraying and baking on the surface of the electroplated part to obtain a first semi-finished product; In step a), the sprayed coating composition includes the electroplating coating paint according to any one of claims 1 to 2; b) performing UV printing on the surface of the first semi-finished product to obtain a second semi-finished product; c) spraying and baking the surface of the second semi-finished product again to obtain a finished product; In step c), the coating component for re-spraying comprises the electroplating coating paint according to any one of claims 1 to 2.

4. The surface treatment method according to claim 3, characterized in that: In step a), the electroplated part is prepared according to the following steps: The blank is sequentially subjected to vulcanization treatment, drying and electroplating to obtain an electroplated part.

5. The surface treatment method according to claim 3, characterized in that: In step a), the sprayed coating composition includes the electroplating coating paint, a thinner and ethylene glycol monobutyl ether.

6. The surface treatment method according to claim 5, characterized in that: The mass ratio of the electroplating paint, the diluent and ethylene glycol monobutyl ether is 10:(5-15):(0.5-2).

7. The surface treatment method according to claim 3, characterized in that: In step c), the coating composition for re-spraying includes the electroplating paint and a thinner; and the finished product is a matte finished product.

8. The surface treatment method according to claim 7, characterized in that: The mass ratio of the electroplating paint to the thinner is 10:(5-15).

9. The surface treatment method according to claim 3, characterized in that: In step c), the coating composition for the second spraying includes the electroplating coating paint, n-amyl acetate, diluent and ethylene glycol monobutyl ether; and the finished product is a bright surface finished product.

10. The surface treatment method according to claim 9, characterized in that: The mass ratio of the electroplating paint, n-amyl acetate, diluent and ethylene glycol monobutyl ether is 10:(0.05-0.2):(5-15):(0.5-2).

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