CN112375493A - Finishing paint for repairing scratches on automobile surface and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of automobile self-repairing finish paint, and particularly relates to finish paint for repairing scratches on an automobile surface and a preparation method thereof, wherein the finish paint for repairing scratches comprises a component A, a component B and a component C, wherein the component A comprises the following raw materials in parts by weight: 40-65 parts of water-based epoxy resin, 33-52 parts of water-based polyurethane resin, 0.2-0.5 part of wetting agent, 0.2-1 part of anti-settling agent, 0.1-0.5 part of defoaming agent, 1-5 parts of dispersing agent and 0.5-1 part of flatting agent. The finish paint for repairing scratches prepared by the invention greatly improves the chemical resistance of the finish paint for repairing scratches, so that the finish paint has excellent water resistance, acid resistance, alkali resistance, salt fog resistance and antifouling performance, simultaneously has very high wear resistance and hardness, effectively reduces the friction coefficient of the paint, improves the tensile strength and elongation at break, loads the corrosion inhibitor into the modified diatomite structure, can better form matrix protection, has excellent corrosion resistance and corrosion resistance, and obviously improves the comprehensive performance.

Description

Finishing paint for repairing scratches on automobile surface and preparation method thereof

Technical Field

The invention relates to the technical field of automobile self-repairing finish paint, in particular to finish paint for repairing scratches on the surface of an automobile and a preparation method thereof.

Background

With the development of industrial economy and urbanization, the automobile output and sales volume in China is continuously the first world in seven years of cicada, and becomes the largest automobile output and sales country in the world. The rapid development of the automotive industry has an obvious pulling effect on the market of automotive coatings, so that the automotive coatings become the most rapidly developed coating varieties and the coating varieties with the highest performance requirements, and therefore, the automotive coatings often represent the highest level of the development of the modern coating industry.

The surface coating for automobiles plays a main role in decoration and protection in the whole coating, and the paint film is required to be plumpy and smooth in appearance, free of flaws, and simultaneously have sufficient hardness, stone impact resistance, chemical resistance, stain resistance, corrosion resistance and the like. However, no matter how good the automobile coating quality is, in the using process, the coating inevitably generates micro cracks and local damage due to the interference of external factors, such as invasion of slurry, splash stones and mechanical rubbing, damage of adhered objects, tree scraping, hard ware scratching, scratching and the like, the surface cannot be seen abnormally, but the mechanical strength of the coating is reduced, the integrity is seriously damaged, and due to the limitation of manual repair, the damaged part cannot be repaired in time, so that the performance of the coating is reduced, the high decoration and luster of the surface are damaged, and the service life of the coating is greatly shortened. Based on the reasons, the automobile coating with the self-repairing function is developed, self-repairing of the damaged part of the coating is realized by depending on the performance of the material, and the automobile coating has great value and application prospect.

At present, the domestic finish paint for repairing scratches on the surfaces of automobiles mainly adopts a two-component waterborne polyurethane coating which is mainly composed of a waterborne resin emulsion component (A component) and a water isocyanate curing agent (B component), has the scratch self-repairing function, but has poor corrosion resistance, corrosion resistance and chemical resistance, unobvious wear resistance and friction reduction performance, unobvious improvement on hardness, tensile strength and elongation at break, and general comprehensive performance.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides the finish paint for repairing the scratches on the surface of the automobile and the preparation method thereof, and solves the problems that the existing finish paint for repairing the scratches on the surface of the automobile has a scratch self-repairing function, but has poor corrosion resistance, corrosion resistance and chemical resistance, unobvious wear resistance and antifriction performance, unobvious improvement on hardness, tensile strength and elongation at break, and general comprehensive performance.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: the finish paint for repairing the scratches on the surface of the automobile comprises a component A, a component B and a component C, wherein the component A comprises the following raw materials in parts by weight: 40-65 parts of water-based epoxy resin, 33-52 parts of water-based polyurethane resin, 0.2-0.5 part of wetting agent, 0.2-1 part of anti-settling agent, 0.1-0.5 part of defoaming agent, 1-5 parts of dispersing agent and 0.5-1 part of flatting agent; the component B comprises the following raw materials in parts by weight: 60-80 parts of a water-based isocyanate curing agent and 20-40 parts of a solvent; the component C comprises the following raw materials in parts by weight: 30-68 parts of fluorine-silicon copolymer resin, 0.3-2 parts of cobalt-tungsten alloy powder, 0.2-1 part of carbon nano tube, 10-15 parts of modified diatomite, 0.5-2 parts of corrosion inhibitor, 5-15 parts of nitric acid solution, 1-10 parts of absolute ethyl alcohol and 15-25 parts of deionized water; wherein the solvent is one or a combination of more of isopropanol, dipropylene glycol methyl ether, dipropylene glycol butyl ether, propylene glycol methyl ether acetate and ethylene glycol butyl ether acetate, and the mesh number of the cobalt-tungsten alloy powder is 60-80 nm.

In a preferred embodiment of the present invention, the wetting agent is one of the series GSK-588/582/585.

As a preferable technical scheme of the invention, the anti-settling agent is one or more of organic bentonite, castor oil derivatives, polyolefin wax particles and fumed silica.

As a preferable technical scheme of the invention, the defoaming agent is modified polysiloxane or organic silicon polymer.

As a preferable technical scheme of the invention, the dispersant is one or more of Gen1252, BYK-190 and Disper 750.

As a preferable technical scheme of the invention, the leveling agent is one of SILCO FLW K-134, L-137 and BYK-300.

As a preferable technical scheme of the invention, the modified diatomite comprises the following preparation steps:

step S1, grinding the diatomite on the premise of not damaging the diatom shells, and roasting the diatomite at 430-450 ℃ after grinding;

and step S2, grafting organic functional macromolecules on the surface of the diatomite treated in the step S1 by using hexadecyl trimethyl ammonium bromide or polyethyleneimine as a modifier, and carrying out organic modification treatment on the surface of the diatomite.

As a preferred technical scheme of the invention, the corrosion inhibitor is a sodium tungstate corrosion inhibitor.

The invention also provides a preparation method of the finish paint for repairing scratches on the surface of the automobile, which comprises the following steps:

s1, weighing the raw materials of the aqueous epoxy resin, the aqueous polyurethane resin, the wetting agent, the anti-settling agent, the defoaming agent, the dispersing agent and the leveling agent in the component A in parts by weight, weighing the raw materials of the aqueous isocyanate curing agent and the solvent in the component B, and the raw materials of the fluorine-silicon copolymer resin, the cobalt-tungsten alloy powder, the carbon nano tube, the modified diatomite, the corrosion inhibitor, the nitric acid solution, the absolute ethyl alcohol and the deionized water in the component C;

step S2, adding the waterborne epoxy resin and the waterborne polyurethane resin into a stirring container, sequentially adding a wetting agent, an anti-settling agent, a defoaming agent, a dispersing agent and a leveling agent under the condition of a rotating speed of 500-800 r/min, dispersing for 20-30 min, and standing to obtain a component A;

step S3, adding the water-based isocyanate curing agent into a stirring container, slowly adding the solvent under the condition of the rotating speed of 500-800 r/min, dispersing for 10-15 min, and standing to obtain a component B;

step S4, adjusting the pH value of a nitric acid solution to 3-5, sequentially adding a corrosion inhibitor, absolute ethyl alcohol and deionized water into the nitric acid solution, uniformly mixing at a rotation speed of 500-800 r/min to obtain a mixed solution containing the corrosion inhibitor, adding modified diatomite into the mixed solution containing the corrosion inhibitor, dispersing for 2-3 hours at a rotation speed of 500-800 r/min to obtain a mixture, performing centrifugal separation, drying and grinding on the obtained mixture, and sieving with a 200-mesh sieve to obtain the modified diatomite loaded with the corrosion inhibitor;

step S5, adding fluorine-silicon copolymer resin into a stirring container, slowly adding cobalt-tungsten alloy powder, carbon nano tubes and deionized water at the rotation speed of 500-800 r/min, dispersing for 15-20 min at the rotation speed of 500-800 r/min to obtain a fluorine-silicon copolymer resin mixture, adding the modified diatomite loaded with the corrosion inhibitor obtained in the step S4 into the fluorine-silicon copolymer resin mixture, and continuously dispersing for 10-15 min to obtain a component C;

and S6, sequentially adding the component B obtained in the step S3 and the component C obtained in the step S5 into the component A obtained in the step S2, dispersing for 3-8 min, and standing to obtain the scratch repairing finish paint.

(III) advantageous effects

Compared with the prior art, the invention provides the finish paint for repairing the scratches on the surface of the automobile and the preparation method thereof, and the finish paint has the following beneficial effects:

the prepared finish paint for repairing the scratches of the automobile surface greatly improves the chemical resistance of the finish paint for repairing the scratches, so that the finish paint has excellent water resistance, acid resistance, alkali resistance, salt fog resistance and antifouling performance, simultaneously has very high abrasion resistance and hardness, effectively reduces the friction coefficient of the paint, improves the tensile strength and the elongation at break, has excellent physical and mechanical properties, can better form matrix protection by loading a corrosion inhibitor into a modified diatomite structure, and has excellent corrosion resistance and corrosion resistance, and the improvement of the comprehensive performance is obvious.

Drawings

FIG. 1 is a schematic diagram of the preparation steps of the topcoat for repairing scratches on the surface of an automobile according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Referring to fig. 1, the present invention provides the following technical solutions: the finish paint for repairing scratches on the surface of an automobile comprises a component A, a component B and a component C, wherein the component A comprises the following raw materials in parts by weight: 65 parts of water-based epoxy resin, 33 parts of water-based polyurethane resin, 0.2 part of wetting agent, 0.2 part of anti-settling agent, 0.1 part of defoaming agent, 1 part of dispersing agent and 0.5 part of flatting agent; the component B comprises the following raw materials in parts by weight: 80 parts of water-based isocyanate curing agent and 20 parts of solvent; the component C comprises the following raw materials in parts by weight: 68 parts of fluorine-silicon copolymer resin, 0.3 part of cobalt-tungsten alloy powder, 0.2-1 part of carbon nano tube, 10 parts of modified diatomite, 0.5 part of corrosion inhibitor, 5 parts of nitric acid solution, 1 part of absolute ethyl alcohol and 15 parts of deionized water; wherein the solvent is dipropylene glycol methyl ether, and the mesh number of the cobalt-tungsten alloy powder is 80 nm.

Specifically, the wetting agent is GSK-582.

Specifically, the anti-settling agent is fumed silica.

Specifically, the defoaming agent is a silicone polymer.

Specifically, the dispersant is BYK-190.

Specifically, the leveling agent is BYK-300.

Specifically, the modified diatomite comprises the following preparation steps:

step S1, grinding the diatomite on the premise of not damaging the diatom shells, and roasting the diatomite at 450 ℃ after grinding;

step S2, grafting organic functional macromolecules onto the surface of the diatomaceous earth treated in step S1 by using polyethyleneimine as a modifier, and subjecting the surface to organic modification treatment.

Specifically, the corrosion inhibitor is a sodium tungstate corrosion inhibitor.

The invention also provides a preparation method of the finish paint for repairing scratches on the surface of the automobile, which comprises the following steps:

s1, weighing the raw materials of the aqueous epoxy resin, the aqueous polyurethane resin, the wetting agent, the anti-settling agent, the defoaming agent, the dispersing agent and the leveling agent in the component A in parts by weight, weighing the raw materials of the aqueous isocyanate curing agent and the solvent in the component B, and the raw materials of the fluorine-silicon copolymer resin, the cobalt-tungsten alloy powder, the carbon nano tube, the modified diatomite, the corrosion inhibitor, the nitric acid solution, the absolute ethyl alcohol and the deionized water in the component C;

step S2, adding the waterborne epoxy resin and the waterborne polyurethane resin into a stirring container, sequentially adding a wetting agent, an anti-settling agent, a defoaming agent, a dispersing agent and a leveling agent under the condition of the rotating speed of 800r/min, dispersing for 30min, and standing to obtain a component A;

step S3, adding the water-based isocyanate curing agent into a stirring container, slowly adding the solvent under the condition of the rotating speed of 800r/min, dispersing for 15min, and standing to obtain a component B;

step S4, adjusting the pH value of the nitric acid solution to 5, sequentially adding a corrosion inhibitor, absolute ethyl alcohol and deionized water into the nitric acid solution, uniformly mixing at the rotation speed of 800r/min to obtain a mixed solution containing the corrosion inhibitor, adding modified diatomite into the mixed solution containing the corrosion inhibitor, dispersing for 3 hours at the rotation speed of 800r/min to obtain a mixture, performing centrifugal separation, drying and grinding on the obtained mixture, and sieving with a 200-mesh sieve to obtain the modified diatomite loaded with the corrosion inhibitor;

step S5, adding fluorine-silicon copolymer resin into a stirring container, slowly adding cobalt-tungsten alloy powder, carbon nano tubes and deionized water at the rotation speed of 800r/min, dispersing for 20min at the rotation speed of 500r/min to obtain a fluorine-silicon copolymer resin mixture, adding the modified diatomite loaded with the corrosion inhibitor obtained in the step S4 into the fluorine-silicon copolymer resin mixture, and continuously dispersing for 15min to obtain a component C;

and S6, adding the component B obtained in the step S3 and the component C obtained in the step S5 into the component A obtained in the step S2 in sequence, dispersing for 3min, and standing to obtain the scratch repair finish paint.

Example 2

Referring to fig. 1, the present invention provides the following technical solutions: the finish paint for repairing scratches on the surface of an automobile comprises a component A, a component B and a component C, wherein the component A comprises the following raw materials in parts by weight: 40 parts of waterborne epoxy resin, 52 parts of waterborne polyurethane resin, 0.5 part of wetting agent, 1 part of anti-settling agent, 0.5 part of defoaming agent, 5 parts of dispersing agent and 1 part of flatting agent; the component B comprises the following raw materials in parts by weight: 60 parts of a water-based isocyanate curing agent and 40 parts of a solvent; the component C comprises the following raw materials in parts by weight: 30 parts of fluorine-silicon copolymer resin, 2 parts of cobalt-tungsten alloy powder, 1 part of carbon nano tube, 15 parts of modified diatomite, 2 parts of corrosion inhibitor, 15 parts of nitric acid solution, 10 parts of absolute ethyl alcohol and 25 parts of deionized water; wherein the solvent is dipropylene glycol butyl ether, and the mesh number of the cobalt-tungsten alloy powder is 60 nm.

Specifically, the wetting agent is GSK-588.

Specifically, the anti-settling agent is organic bentonite.

Specifically, the defoaming agent is modified polysiloxane.

Specifically, the dispersant is Gen 1252.

Specifically, the leveling agent is SILCO FLW K-134.

Specifically, the modified diatomite comprises the following preparation steps:

step S1, grinding the diatomite on the premise of not damaging the diatom shell, and roasting the diatomite at 430 ℃ after grinding;

step S2, grafting organic functional macromolecules on the surface of the diatomite treated in the step S1 by using hexadecyl trimethyl ammonium bromide as a modifier, and carrying out organic modification treatment on the surface of the diatomite.

Specifically, the corrosion inhibitor is a sodium tungstate corrosion inhibitor.

The invention also provides a preparation method of the finish paint for repairing scratches on the surface of the automobile, which comprises the following steps:

s1, weighing the raw materials of the aqueous epoxy resin, the aqueous polyurethane resin, the wetting agent, the anti-settling agent, the defoaming agent, the dispersing agent and the leveling agent in the component A in parts by weight, weighing the raw materials of the aqueous isocyanate curing agent and the solvent in the component B, and the raw materials of the fluorine-silicon copolymer resin, the cobalt-tungsten alloy powder, the carbon nano tube, the modified diatomite, the corrosion inhibitor, the nitric acid solution, the absolute ethyl alcohol and the deionized water in the component C;

step S2, adding the waterborne epoxy resin and the waterborne polyurethane resin into a stirring container, sequentially adding a wetting agent, an anti-settling agent, a defoaming agent, a dispersing agent and a leveling agent under the condition of a rotating speed of 500r/min, dispersing for 20min, and standing to obtain a component A;

step S3, adding the water-based isocyanate curing agent into a stirring container, slowly adding the solvent under the condition of the rotation speed of 500r/min, dispersing for 10min, and standing to obtain a component B;

step S4, adjusting the pH value of the nitric acid solution to 3, sequentially adding a corrosion inhibitor, absolute ethyl alcohol and deionized water into the nitric acid solution, uniformly mixing at a rotation speed of 500r/min to obtain a mixed solution containing the corrosion inhibitor, adding modified diatomite into the mixed solution containing the corrosion inhibitor, dispersing for 2 hours at a rotation speed of 500r/min to obtain a mixture, performing centrifugal separation, drying and grinding on the obtained mixture, and sieving with a 200-mesh sieve to obtain the modified diatomite loaded with the corrosion inhibitor;

step S5, adding fluorine-silicon copolymer resin into a stirring container, slowly adding cobalt-tungsten alloy powder, carbon nano tubes and deionized water at the rotation speed of 500r/min, dispersing for 15min at the rotation speed of 500r/min to obtain a fluorine-silicon copolymer resin mixture, adding the modified diatomite loaded with the corrosion inhibitor obtained in the step S4 into the fluorine-silicon copolymer resin mixture, and continuously dispersing for 10min to obtain a component C;

and S6, adding the component B obtained in the step S3 and the component C obtained in the step S5 into the component A obtained in the step S2 in sequence, dispersing for 5min, and standing to obtain the scratch repair finish paint.

Example 3

Referring to fig. 1, the present invention provides the following technical solutions: the finish paint for repairing scratches on the surface of an automobile comprises a component A, a component B and a component C, wherein the component A comprises the following raw materials in parts by weight: 55 parts of water-based epoxy resin, 40 parts of water-based polyurethane resin, 0.3 part of wetting agent, 0.6 part of anti-settling agent, 0.4 part of defoaming agent, 3 parts of dispersing agent and 0.7 part of flatting agent; the component B comprises the following raw materials in parts by weight: 70 parts of water-based isocyanate curing agent and 30 parts of solvent; the component C comprises the following raw materials in parts by weight: 50 parts of fluorine-silicon copolymer resin, 1.5 parts of cobalt-tungsten alloy powder, 0.5 part of carbon nano tube, 13 parts of modified diatomite, 1 part of corrosion inhibitor, 10 parts of nitric acid solution, 5 parts of absolute ethyl alcohol and 20 parts of deionized water; wherein the solvent is ethylene glycol monobutyl ether acetate, and the mesh number of the cobalt-tungsten alloy powder is 70 nm.

Specifically, the wetting agent is GSK-585.

Specifically, the anti-settling agent is a castor oil derivative.

Specifically, the defoaming agent is a silicone polymer.

Specifically, the dispersant is Disper 750.

Specifically, the leveling agent is SILCO FLW L-137.

Specifically, the modified diatomite comprises the following preparation steps:

step S1, grinding the diatomite on the premise of not damaging the frustules, and roasting the diatomite at 440 ℃ after grinding;

step S2, grafting organic functional macromolecules on the surface of the diatomite treated in the step S1 by using hexadecyl trimethyl ammonium bromide as a modifier, and carrying out organic modification treatment on the surface of the diatomite.

Specifically, the corrosion inhibitor is a sodium tungstate corrosion inhibitor.

The invention also provides a preparation method of the finish paint for repairing scratches on the surface of the automobile, which comprises the following steps:

s1, weighing the raw materials of the aqueous epoxy resin, the aqueous polyurethane resin, the wetting agent, the anti-settling agent, the defoaming agent, the dispersing agent and the leveling agent in the component A in parts by weight, weighing the raw materials of the aqueous isocyanate curing agent and the solvent in the component B, and the raw materials of the fluorine-silicon copolymer resin, the cobalt-tungsten alloy powder, the carbon nano tube, the modified diatomite, the corrosion inhibitor, the nitric acid solution, the absolute ethyl alcohol and the deionized water in the component C;

step S2, adding the waterborne epoxy resin and the waterborne polyurethane resin into a stirring container, sequentially adding a wetting agent, an anti-settling agent, a defoaming agent, a dispersing agent and a leveling agent under the condition of the rotating speed of 600r/min, dispersing for 25min, and standing to obtain a component A;

step S3, adding the water-based isocyanate curing agent into a stirring container, slowly adding the solvent under the condition of the rotating speed of 700r/min, dispersing for 13min, and standing to obtain a component B;

step S4, adjusting the pH value of the nitric acid solution to 4, sequentially adding a corrosion inhibitor, absolute ethyl alcohol and deionized water into the nitric acid solution, uniformly mixing at a rotation speed of 650r/min to obtain a mixed solution containing the corrosion inhibitor, adding modified diatomite into the mixed solution containing the corrosion inhibitor, dispersing for 2.5 hours at a rotation speed of 600r/min to obtain a mixture, performing centrifugal separation, drying and grinding on the obtained mixture, and sieving with a 200-mesh sieve to obtain the modified diatomite loaded with the corrosion inhibitor;

step S5, adding fluorine-silicon copolymer resin into a stirring container, slowly adding cobalt-tungsten alloy powder, carbon nano tubes and deionized water at the rotation speed of 700r/min, dispersing for 18min at the rotation speed of 600r/min to obtain a fluorine-silicon copolymer resin mixture, adding the modified diatomite loaded with the corrosion inhibitor obtained in the step S4 into the fluorine-silicon copolymer resin mixture, and continuously dispersing for 12min to obtain a component C;

and S6, adding the component B obtained in the step S3 and the component C obtained in the step S5 into the component A obtained in the step S2 in sequence, dispersing for 8min, and standing to obtain the scratch repair finish paint.

Comparative example 1

This comparative example is a comparative example to example 1, the main differences with respect to example 1 being: the scratch repair finishing coat comprises a component A and a component B, wherein the component A comprises the following raw materials in parts by weight: 65 parts of water-based epoxy resin, 33 parts of water-based polyurethane resin, 0.2 part of wetting agent, 0.2 part of anti-settling agent, 0.1 part of defoaming agent, 1 part of dispersing agent and 0.5 part of flatting agent; the component B comprises the following raw materials in parts by weight: 80 parts of water-based isocyanate curing agent and 20 parts of solvent.

The comparison of the performance of the scratch repair topcoat prepared in examples 1-3 with that of the scratch repair topcoat prepared in the prior art (comparative example 1) was examined as follows:

as can be seen from the above table, the scratch repair finish paint is formed by 3 components, due to the fact that the fluorine-silicon copolymer resin is added into the paint, and the cobalt-tungsten alloy powder is added into the fluorine-silicon copolymer resin, the chemical resistance of the scratch repair finish paint is greatly improved, the scratch repair finish paint has excellent water resistance, acid resistance, alkali resistance, salt fog resistance and antifouling performance, meanwhile, the paint has high wear resistance and hardness, the friction coefficient of the paint is effectively reduced through the addition of the carbon nano tubes, the tensile strength and the elongation at break are improved, the physical and mechanical properties are excellent, on the other hand, the corrosion inhibitor is loaded into the modified diatomite structure, matrix protection can be better formed, and the scratch repair finish paint has excellent corrosion resistance and corrosion resistance.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (9)

1. The finishing paint for repairing the scratches on the surface of the automobile is characterized in that: the scratch repair finish paint comprises a component A, a component B and a component C, wherein the component A comprises the following raw materials in parts by weight: 40-65 parts of water-based epoxy resin, 33-52 parts of water-based polyurethane resin, 0.2-0.5 part of wetting agent, 0.2-1 part of anti-settling agent, 0.1-0.5 part of defoaming agent, 1-5 parts of dispersing agent and 0.5-1 part of flatting agent; the component B comprises the following raw materials in parts by weight: 60-80 parts of a water-based isocyanate curing agent and 20-40 parts of a solvent; the component C comprises the following raw materials in parts by weight: 30-68 parts of fluorine-silicon copolymer resin, 0.3-2 parts of cobalt-tungsten alloy powder, 0.2-1 part of carbon nano tube, 10-15 parts of modified diatomite, 0.5-2 parts of corrosion inhibitor, 5-15 parts of nitric acid solution, 1-10 parts of absolute ethyl alcohol and 15-25 parts of deionized water; wherein the solvent is one or a combination of more of isopropanol, dipropylene glycol methyl ether, dipropylene glycol butyl ether, propylene glycol methyl ether acetate and ethylene glycol butyl ether acetate, and the mesh number of the cobalt-tungsten alloy powder is 60-80 nm.

2. The finish paint for repairing scratches on the surface of an automobile according to claim 1, wherein: the wetting agent is one of the series of GSK-588/582/585.

3. The finish paint for repairing scratches on the surface of an automobile according to claim 1, wherein: the anti-settling agent is one or a combination of more of organic bentonite, castor oil derivatives, polyolefin wax particles and fumed silica.

4. The finish paint for repairing scratches on the surface of an automobile according to claim 1, wherein: the defoaming agent is modified polysiloxane or organic silicon polymer.

5. The finish paint for repairing scratches on the surface of an automobile according to claim 1, wherein: the dispersant is one or more of Gen1252, BYK-190 and Disper 750.

6. The finish paint for repairing scratches on the surface of an automobile according to claim 1, wherein: the leveling agent is one of SILCO FLW K-134, L-137 and BYK-300.

7. The finish paint for repairing scratches on the surface of an automobile according to claim 1, wherein: the modified diatomite comprises the following preparation steps:

step S1, grinding the diatomite on the premise of not damaging the diatom shells, and roasting the diatomite at 430-450 ℃ after grinding;

and step S2, grafting organic functional macromolecules on the surface of the diatomite treated in the step S1 by using hexadecyl trimethyl ammonium bromide or polyethyleneimine as a modifier, and carrying out organic modification treatment on the surface of the diatomite.

8. The finish paint for repairing scratches on the surface of an automobile according to claim 1, wherein: the corrosion inhibitor is a sodium tungstate corrosion inhibitor.

9. The method for preparing a topcoat for repairing scratches on an automotive surface according to any one of claims 1 to 8, wherein: the method comprises the following steps:

s1, weighing the raw materials of the aqueous epoxy resin, the aqueous polyurethane resin, the wetting agent, the anti-settling agent, the defoaming agent, the dispersing agent and the leveling agent in the component A in parts by weight, weighing the raw materials of the aqueous isocyanate curing agent and the solvent in the component B, and the raw materials of the fluorine-silicon copolymer resin, the cobalt-tungsten alloy powder, the carbon nano tube, the modified diatomite, the corrosion inhibitor, the nitric acid solution, the absolute ethyl alcohol and the deionized water in the component C;

step S2, adding the waterborne epoxy resin and the waterborne polyurethane resin into a stirring container, sequentially adding a wetting agent, an anti-settling agent, a defoaming agent, a dispersing agent and a leveling agent under the condition of a rotating speed of 500-800 r/min, dispersing for 20-30 min, and standing to obtain a component A;

step S3, adding the water-based isocyanate curing agent into a stirring container, slowly adding the solvent under the condition of the rotating speed of 500-800 r/min, dispersing for 10-15 min, and standing to obtain a component B;

step S4, adjusting the pH value of a nitric acid solution to 3-5, sequentially adding a corrosion inhibitor, absolute ethyl alcohol and deionized water into the nitric acid solution, uniformly mixing at a rotation speed of 500-800 r/min to obtain a mixed solution containing the corrosion inhibitor, adding modified diatomite into the mixed solution containing the corrosion inhibitor, dispersing for 2-3 hours at a rotation speed of 500-800 r/min to obtain a mixture, performing centrifugal separation, drying and grinding on the obtained mixture, and sieving with a 200-mesh sieve to obtain the modified diatomite loaded with the corrosion inhibitor;

step S5, adding fluorine-silicon copolymer resin into a stirring container, slowly adding cobalt-tungsten alloy powder, carbon nano tubes and deionized water at the rotation speed of 500-800 r/min, dispersing for 15-20 min at the rotation speed of 500-800 r/min to obtain a fluorine-silicon copolymer resin mixture, adding the modified diatomite loaded with the corrosion inhibitor obtained in the step S4 into the fluorine-silicon copolymer resin mixture, and continuously dispersing for 10-15 min to obtain a component C;

and S6, sequentially adding the component B obtained in the step S3 and the component C obtained in the step S5 into the component A obtained in the step S2, dispersing for 3-8 min, and standing to obtain the scratch repairing finish paint.

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