Electrosilvering imitation coating with high wear resistance and high corrosion resistance and preparation method thereof

Abstract

The invention relates to the technical field of high-performance coatings, and provides a high-wear-resistance and high-corrosion-resistance electrosilvering imitation coating and a preparation method thereof. The carbon quantum dot / polyurethane interpenetrating cross-linked network material coated and modified flaky aluminum powder is prepared through the following processes: (1) preparing a carbon quantum dot dispersion liquid of which the surface is rich in functional groups such as hydroxyl, carboxyl and amino by a hydrothermal method; (2) preparing linear polyurethane containing C = C; (3) uniformly mixing the carbon quantum dot dispersion liquid, linear polyurethane, epoxypropane, an acid catalyst and a photoinitiator, and spraying the mixture on the surface of the flaky aluminum powder; and (4) sequentially enabling the carbon quantum dots and polyurethane to respectively form a cross-linked network structure. The surface modified flaky aluminum powder is mixed with cellulose acetate butyrate, acrylate resin, an organic solvent and an auxiliary agent, so that the electrosilvering imitation coating with excellent wear resistance and corrosion resistance can be obtained.

Description

Technical Field

[0001] The invention relates to the technical field of high-performance coatings, and provides a highly wear-resistant and highly corrosion-resistant imitation electroplating silver coating and a preparation method thereof. Background Art

[0002] Aluminum powder paint is often used on plastic surfaces. It not only protects the surface, but also beautifies the appearance due to its metallic glitter and decorative effects. However, ordinary aluminum powder paint has defects such as poor gloss and vividness, poor wear resistance and scratch resistance, poor solvent resistance and weather resistance, and corrosion resistance needs to be improved. By improving its performance and obtaining an imitation electroplating silver coating, the application value of aluminum powder paint can be improved. The components of aluminum powder paint mainly include solvents, flaky aluminum powder, film-forming substances, additives, etc., and performance improvement can start from these components.

[0003] In terms of film-forming materials, cellulose acetate butyrate can be used to obtain imitation electroplating silver coatings with good adhesion, yellowing resistance and polishing properties. Its grafting modification can also improve gloss, mirror effect, solvent resistance, etc. In terms of solvents, the use of composite solvents with appropriate solubility and evaporation rate can form a certain liquid convection in the wet film state, which is conducive to the directional arrangement of aluminum powder. In terms of additives, the optimization or performance improvement of film-forming additives, aluminum powder directional additives, etc. can also improve the comprehensive performance of the coating.

[0004] Aluminum powder is an important component of silver-plated coatings. Modification of aluminum powder can significantly improve the performance of coatings in various aspects. In the prior art, aluminum powder modification involves the following aspects: organic coating modification of aluminum powder to improve dispersibility and interface bonding, or inorganic coating modification to improve antioxidant performance; chemical coupling agent treatment of the aluminum powder surface to improve coating adhesion and water resistance; forming a dense oxide film on the aluminum powder surface by chemical oxidation or electrochemical methods to improve corrosion resistance and surface stability; loading conductive nanomaterials on the aluminum powder surface to provide coating conductivity; hydrophobic or super-hydrophobic modification of the aluminum powder surface to give the coating self-cleaning function and anti-icing performance. Summary of the invention

[0005] The invention provides a highly wear-resistant and highly corrosion-resistant imitation electroplating silver coating and a preparation method thereof, and aims to improve the wear resistance and corrosion resistance of the coating by performing surface coating modification on aluminum powder.

[0006] To achieve the above purpose, the specific technical solution of the present invention is as follows: Firstly, the present invention provides a highly wear-resistant and highly corrosion-resistant imitation electroplating silver coating.

[0007] The components of the imitation electroplating silver coating include surface modified flaky aluminum powder, cellulose acetate butyrate, acrylic resin, organic solvent and auxiliary agent.

[0008] The distribution ratio of each group is: the mass ratio of surface modified flaky aluminum powder, cellulose acetate butyrate, polyacrylate resin, organic solvent and additive is 15-25:30-45:5-20:100:0.5-3.

[0009] Wherein, the surface modified flaky aluminum powder is flaky aluminum powder coated and modified by carbon quantum dots / polyurethane interpenetrating cross-linked network material.

[0010] Preferably, the flaky aluminum powder has a thickness of 0.1-0.2 μm and a diameter-to-thickness ratio of 80-120:1.

[0011] Preferably, the acrylic resin is one of polymethyl methacrylate, polyethyl methacrylate, polymethyl acrylate and polyethyl acrylate.

[0012] Preferably, the organic solvent is composed of solvent A and solvent B in a mass ratio of 1:0.8-1.5, solvent A is one of ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, and hexyl acetate, and solvent B is one of cyclohexanone, cyclopentanone, methyl ethyl ketone, and methyl isobutyl ketone.

[0013] Preferably, the auxiliary agent is one or more of a stabilizer, a dispersant, an antioxidant, a leveling agent, and a defoaming agent.

[0014] The present invention also provides a method for preparing the surface-modified flaky aluminum powder, and the specific preparation steps are: (1) Add sodium citrate and urea to deionized water and stir to dissolve, pour into a PTFE-lined stainless steel reactor, stir at 200-400 rpm, hydrothermally react at 210-230° C. for 2-4 h, cool, filter, centrifuge and concentrate the supernatant to obtain a carbon quantum dot dispersion; (2) adding isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate into a reaction vessel, stirring at a speed of 100-200 rpm, reacting in a water bath at 50-60° C. for 1-2 hours, and then cooling to room temperature to obtain a viscous polyurethane; (3) mixing the carbon quantum dot dispersion, viscous polyurethane, propylene oxide, acid catalyst, and photoinitiator evenly, and spraying them evenly on the surface of the flaky aluminum powder; (4) First react at 60-80℃ for 8-10h, then age at room temperature for 18-24h, freeze-dry, and then use a UV curing machine to illuminate for 20-30s.

[0015] The above step (1) is to prepare nitrogen-doped carbon quantum dots by a hydrothermal method using sodium citrate as a carbon source and urea as a nitrogen source. It is well known that the surface of the carbon quantum dots prepared by this method contains a large number of functional groups such as hydroxyl, carboxyl, and amino groups, which not only give the carbon quantum dots hydrophilicity, but also give them surface reactivity. Preferably, in step (1), the mass ratio of sodium citrate, urea, and deionized water is 3-5:8-10:100. Further preferably, in step (1), filter paper with a pore size of 0.22μm is used for filtration; the centrifugal speed is 10000-15000rpm, and the time is 5-20min; the solid content of the supernatant after concentration is 40-60wt%.

[0016] The above step (2) is a process of synthesizing polyurethane using isophorone diisocyanate and 2,3-dihydroxypropyl acrylate as monomers and dibutyltin dilaurate as a catalyst. Isophorone diisocyanate contains two isocyanate groups, and 2,3-dihydroxypropyl acrylate contains two hydroxyl groups and one C=C. The polycondensation of the two produces a polyurethane containing a linear structure of C=C. Preferably, in step (2), the mass ratio of isophorone diisocyanate, 2,3-dihydroxypropyl acrylate, and dibutyltin dilaurate is 100:68-72:1.2-1.5.

[0017] In the above step (3), the carbon quantum dot dispersion is mixed with the viscous polyurethane, the carbon quantum dots are diffused between the polyurethane molecular chains, and propylene oxide, an acidic catalyst, and a photoinitiator are added for mixing, and then sprayed on the surface of the flaky aluminum powder. Preferably, in step (3), the acidic catalyst is HCl or H2SO4; the photoinitiator is composed of TPO-L and 1173 in a mass ratio of 1:0.8-1.2. Further preferably, in step (3), the mass ratio of the carbon quantum dot dispersion, the viscous polyurethane, propylene oxide, the acidic catalyst, the photoinitiator, and the flaky aluminum powder is 8-16:20:2-4:0.2-0.4:0.1-0.5:100.

[0018] The above step (4) is divided into two processes. First, under the action of heating at 60-80°C and an acidic catalyst, the epoxy group of propylene oxide is ring-opened and condensed with the hydroxyl group on the surface of the carbon quantum dots to form an ether bond. The continuous condensation between the hydroxyl groups can make the carbon quantum dots interconnected to form a network structure. In addition, other groups on the surface of the carbon quantum dots (such as carboxyl and amino groups) can also interact (such as hydrogen bonds) with each other, forming mutual connections during the aging process, which can further improve the crosslinking degree of the three-dimensional network of carbon quantum dots. Second, in the presence of a photoinitiator, ultraviolet light is irradiated to induce the C=C on the polyurethane structure to react, so that the polyurethane segments are connected, thereby transforming the polyurethane from a linear structure to a crosslinked network structure. As a result, a carbon quantum dot / polyurethane interpenetrating crosslinked network material coating layer is formed on the surface of the flaky aluminum powder.

[0019] Then, the invention provides a preparation method of the above-mentioned highly wear-resistant and highly corrosion-resistant imitation electroplating silver coating.

[0020] The specific preparation process of the imitation electroplating silver coating is as follows: S1, adding the surface modified flaky aluminum powder into 1 / 3 organic solvent, stirring and dispersing the powder evenly to obtain dispersion A; S2, adding cellulose acetate butyrate, acrylate resin and additives into 2 / 3 organic solvent, stirring and dissolving, to obtain solution B; S3, adding dispersion A into solution B and stirring evenly.

[0021] The present invention in situ prepares a carbon quantum dot / polyurethane interpenetrating cross-linked network material as a coating layer on the surface of flaky aluminum powder. It is well known that polyurethane is a polymer material with good wear resistance. It has a microphase separation structure. The isocyanate hard segment can provide high strength and hardness to resist external forces, which is the basis of its good wear resistance. The polyol soft segment can absorb energy through elastic deformation and reduce friction damage. Carbon quantum dots are usually used as an anti-wear additive, which can not only hinder the dislocation movement of the material and improve the surface hardness of the material, but also disperse stress to delay crack propagation, and form a lubricating layer through surface functional groups to reduce the friction coefficient of the material. It can be seen that the wear resistance principles of polyurethane and carbon quantum dots are different, and the conventional application method is to directly add carbon quantum dots to polyurethane to form a composite material.

[0022] The application mode of the present invention is to form an interpenetrating cross-linked network composite material with carbon quantum dots and polyurethane, in which the carbon quantum dots themselves form a three-dimensional cross-linked network structure, and the polyurethane itself also forms a three-dimensional cross-linked network structure, and the cross-linked networks of the two interpenetrate each other. In this application mode, since the carbon quantum dots form a cross-linked network skeleton and interpenetrate with the polyurethane cross-linked network, the obstruction of the dislocation movement of the polyurethane material by the carbon quantum dots is more obvious, and in the interpenetrating network structure, the stress is more easily transmitted and dispersed between the two networks, which is not only conducive to the polyurethane absorbing energy through elastic deformation and promoting stress attenuation, but also conducive to the carbon quantum dot skeleton to play the role of terminating microcracks and preventing crack propagation, therefore, the present invention forms an interpenetrating cross-linked network material with carbon quantum dots and polyurethane and wraps it on the surface of flaky aluminum powder, which can more fully play the wear-resistant effect of two substances based on different wear-resistant mechanisms, thereby giving the imitation electroplating silver coating excellent wear resistance.

[0023] In addition, it is known that polyurethane and carbon quantum dots themselves have good anti-corrosion properties. In the present invention, since the two form an interpenetrating cross-linked network structure, any one network is interspersed in the other network, occupying the other network gap, forming a network barrier that is more dense than a single network, and thus has better barrier properties against corrosive media. Moreover, the interpenetration of the two networks will limit each other's mobility, improve structural stability, make the coating less likely to swell and cause structural relaxation, and make it more difficult for corrosive media to penetrate. Therefore, the carbon quantum dots and polyurethane form an interpenetrating cross-linked network structure to coat the flaky aluminum powder, which can further improve the corrosion resistance of the coating.

[0024] In summary, the present invention provides a highly wear-resistant and highly corrosion-resistant imitation electroplating silver coating and a preparation method thereof, and its beneficial effects are: The present invention prepares the flaky aluminum powder coated with carbon quantum dot / polyurethane interpenetrating cross-linked network material through the following process: (1) preparing a carbon quantum dot dispersion rich in functional groups such as hydroxyl, carboxyl, and amino groups on the surface by a hydrothermal method; (2) preparing a linear polyurethane containing C=C; (3) mixing the carbon quantum dot dispersion, polyurethane, propylene oxide, an acid catalyst, and a photoinitiator uniformly and spraying them on the surface of the flaky aluminum powder; (4) sequentially forming a cross-linked network structure for the carbon quantum dots and the polyurethane. The surface-modified flaky aluminum powder is mixed with cellulose acetate butyrate, acrylate resin, an organic solvent, and an additive to obtain an electroplating silver coating with excellent wear resistance and corrosion resistance. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below through specific embodiments, but this should not be construed as limiting the scope of the present invention to the following examples. Without departing from the above-mentioned method concept of the present invention, various substitutions or changes made according to common technical knowledge and conventional means in the art should be included in the scope of the present invention. Example 1

[0026] Preparation of surface modified flake aluminum powder: (1) Sodium citrate and urea were added to deionized water and stirred to dissolve, then poured into a PTFE-lined stainless steel reactor, stirred at 300 rpm, hydrothermally reacted at 220°C for 3 h, cooled, filtered with 0.22 μm filter paper, centrifuged at 12000 rpm for 10 min, and the supernatant was concentrated to a solid content of 50 wt% to obtain a carbon quantum dot dispersion; the mass ratio of sodium citrate, urea, and deionized water was 4:9:100; (2) adding isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate into a reaction vessel, stirring at a speed of 150 rpm, reacting in a water bath at 55°C for 1.5 hours, and then cooling to room temperature to obtain a viscous polyurethane; the mass ratio of isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate is 100:70:1.3; (3) Mix the carbon quantum dot dispersion, viscous polyurethane, propylene oxide, acidic catalyst and photoinitiator evenly, and spray them evenly on the surface of flaky aluminum powder; the mass ratio of carbon quantum dot dispersion, viscous polyurethane, propylene oxide, acidic catalyst, photoinitiator and flaky aluminum powder is 8:20:2:0.2:0.3:100; the acidic catalyst is HCl; the photoinitiator is composed of TPO-L and 1173 in a mass ratio of 1:1; (4) First react at 70℃ for 8h, then age at room temperature for 20h, freeze-dry, and then use a UV curing machine to illuminate for 25s.

[0027] Preparation of imitation electroplating silver coating: S1, adding the surface modified flaky aluminum powder into 1 / 3 organic solvent, stirring and dispersing the powder evenly to obtain dispersion A; S2, adding cellulose acetate butyrate, acrylate resin and additives into 2 / 3 organic solvent, stirring and dissolving, to obtain solution B; S3, adding dispersion A into solution B and stirring evenly.

[0028] The mass ratio of surface modified aluminum flake powder, cellulose acetate butyrate, polyacrylate resin, organic solvent and additive is 20:38:12:100:0.8. Among the raw materials involved: the average thickness of aluminum flake powder is 0.15μm, and the diameter-thickness ratio is 100:1; the model of cellulose acetate butyrate is CAB-381-20; the acrylic resin is polymethyl methacrylate; the organic solvent is composed of hexyl acetate and cyclohexanone in a mass ratio of 1:1; the additive is composed of silicone leveling agent BYK-306 and defoaming agent TEGO Foamex805 in a mass ratio of 5:3. Comparative Example 1

[0029] Preparation of surface modified flake aluminum powder: (1) Sodium citrate and urea were added to deionized water and stirred to dissolve, then poured into a PTFE-lined stainless steel reactor, stirred at 300 rpm, hydrothermally reacted at 220°C for 3 h, cooled, filtered with 0.22 μm filter paper, centrifuged at 12000 rpm for 10 min, and the supernatant was concentrated to a solid content of 50 wt% to obtain a carbon quantum dot dispersion; the mass ratio of sodium citrate, urea, and deionized water was 4:9:100; (2) adding isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate into a reaction vessel, stirring at a speed of 150 rpm, reacting in a water bath at 55°C for 1.5 hours, and then cooling to room temperature to obtain a viscous polyurethane; the mass ratio of isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate is 100:70:1.3; (3) Mix the carbon quantum dot dispersion, viscous polyurethane and photoinitiator evenly, and spray them evenly on the surface of the flaky aluminum powder; the mass ratio of the carbon quantum dot dispersion, viscous polyurethane, photoinitiator and flaky aluminum powder is 8:20:0.3:100; the photoinitiator is composed of TPO-L and 1173 in a mass ratio of 1:1; (4) Vacuum dry, then use a UV light curing machine to illuminate for 25 seconds.

[0030] Preparation of imitation electroplating silver coating: same as Example 1. Example 2

[0031] Preparation of surface modified flake aluminum powder: (1) Sodium citrate and urea were added to deionized water and stirred to dissolve, then poured into a PTFE-lined stainless steel reactor, stirred at 300 rpm, hydrothermally reacted at 220°C for 3 h, cooled, filtered with 0.22 μm filter paper, centrifuged at 12000 rpm for 10 min, and the supernatant was concentrated to a solid content of 50 wt% to obtain a carbon quantum dot dispersion; the mass ratio of sodium citrate, urea, and deionized water was 4:9:100; (2) adding isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate into a reaction vessel, stirring at a speed of 150 rpm, reacting in a water bath at 55°C for 1.5 hours, and then cooling to room temperature to obtain a viscous polyurethane; the mass ratio of isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate is 100:70:1.3; (3) Mix the carbon quantum dot dispersion, viscous polyurethane, propylene oxide, acidic catalyst and photoinitiator evenly, and spray them evenly on the surface of flaky aluminum powder; the mass ratio of carbon quantum dot dispersion, viscous polyurethane, propylene oxide, acidic catalyst, photoinitiator and flaky aluminum powder is 12:20:3:0.3:0.3:100; the acidic catalyst is HCl; the photoinitiator is composed of TPO-L and 1173 in a mass ratio of 1:1; (4) First react at 75℃ for 9h, then age at room temperature for 20h, freeze-dry, and then use a UV curing machine to illuminate for 25s.

[0032] Preparation of imitation electroplating silver coating: The steps and proportions are the same as those in Example 1. The raw materials involved are: the flaky aluminum powder is the same as in Example 1; the cellulose acetate butyrate is the same as in Example 1; the acrylate resin is polyethyl methacrylate; the organic solvent is composed of ethyl acetate and cyclopentanone in a mass ratio of 1:1; and the auxiliary agent is the same as in Example 1. Comparative Example 2

[0033] Preparation of surface modified flake aluminum powder: (1) Sodium citrate and urea were added to deionized water and stirred to dissolve, then poured into a PTFE-lined stainless steel reactor, stirred at 300 rpm, hydrothermally reacted at 220°C for 3 h, cooled, filtered with 0.22 μm filter paper, centrifuged at 12000 rpm for 10 min, and the supernatant was concentrated to a solid content of 50 wt% to obtain a carbon quantum dot dispersion; the mass ratio of sodium citrate, urea, and deionized water was 4:9:100; (2) adding isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate into a reaction vessel, stirring at a speed of 150 rpm, reacting in a water bath at 55°C for 1.5 hours, and then cooling to room temperature to obtain a viscous polyurethane; the mass ratio of isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate is 100:70:1.3; (3) Mix the carbon quantum dot dispersion, viscous polyurethane and photoinitiator evenly, and spray them evenly on the surface of the flaky aluminum powder; the mass ratio of the carbon quantum dot dispersion, viscous polyurethane, photoinitiator and flaky aluminum powder is 12:20:0.3:100; the photoinitiator is composed of TPO-L and 1173 in a mass ratio of 1:1; (4) Vacuum dry, then use a UV light curing machine to illuminate for 25 seconds.

[0034] Preparation of imitation electroplating silver coating: same as Example 2. Example 3

[0035] Preparation of surface modified flake aluminum powder: (1) Sodium citrate and urea were added to deionized water and stirred to dissolve, then poured into a PTFE-lined stainless steel reactor, stirred at 300 rpm, hydrothermally reacted at 220°C for 3 h, cooled, filtered with 0.22 μm filter paper, centrifuged at 12000 rpm for 10 min, and the supernatant was concentrated to a solid content of 50 wt% to obtain a carbon quantum dot dispersion; the mass ratio of sodium citrate, urea, and deionized water was 4:9:100; (2) adding isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate into a reaction vessel, stirring at a speed of 150 rpm, reacting in a water bath at 55°C for 1.5 hours, and then cooling to room temperature to obtain a viscous polyurethane; the mass ratio of isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate is 100:70:1.3; (3) Mix the carbon quantum dot dispersion, viscous polyurethane, propylene oxide, acidic catalyst and photoinitiator evenly, and spray them evenly on the surface of flaky aluminum powder; the mass ratio of carbon quantum dot dispersion, viscous polyurethane, propylene oxide, acidic catalyst, photoinitiator and flaky aluminum powder is 16:20:4:0.4:0.3:100; the acidic catalyst is HCl; the photoinitiator is composed of TPO-L and 1173 in a mass ratio of 1:1; (4) First react at 75℃ for 10h, then age at room temperature for 20h, freeze-dry, and then use a UV curing machine to illuminate for 25s.

[0036] Preparation of imitation electroplating silver coating: The steps and proportions are the same as those in Example 1. The raw materials involved are: the flaky aluminum powder is the same as in Example 1; the cellulose acetate butyrate is the same as in Example 1; the acrylic resin is polyethyl acrylate; the organic solvent is composed of butyl acetate and methyl isobutyl ketone in a mass ratio of 1:1; and the auxiliary agent is the same as in Example 1. Comparative Example 3

[0037] Preparation of surface modified flake aluminum powder: (1) Sodium citrate and urea were added to deionized water and stirred to dissolve, then poured into a PTFE-lined stainless steel reactor, stirred at 300 rpm, hydrothermally reacted at 220°C for 3 h, cooled, filtered with 0.22 μm filter paper, centrifuged at 12000 rpm for 10 min, and the supernatant was concentrated to a solid content of 50 wt% to obtain a carbon quantum dot dispersion; the mass ratio of sodium citrate, urea, and deionized water was 4:9:100; (2) adding isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate into a reaction vessel, stirring at a speed of 150 rpm, reacting in a water bath at 55°C for 1.5 hours, and then cooling to room temperature to obtain a viscous polyurethane; the mass ratio of isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate is 100:70:1.3; (3) Mix the carbon quantum dot dispersion, viscous polyurethane and photoinitiator evenly, and spray them evenly on the surface of the flaky aluminum powder; the mass ratio of the carbon quantum dot dispersion, viscous polyurethane, photoinitiator and flaky aluminum powder is 16:20:0.3:100; the photoinitiator is composed of TPO-L and 1173 in a mass ratio of 1:1; (4) Vacuum dry, then use a UV light curing machine to illuminate for 25 seconds.

[0038] Preparation of imitation electroplating silver coating: same as Example 3.

[0039] Wear resistance test: the coating prepared by embodiment 1-3 and comparative example 1-3 is sprayed onto the ABS substrate surface respectively, vacuum dried to form a coating of 20 μm thickness. Use an eraser-resistant wiping instrument, place a 500g weight on an eraser of 2 cm in diameter, wipe the coating on the ABS substrate surface back and forth, and the wiping frequency is one back and forth per second, until the coating is rubbed to expose the ABS substrate, calculate the number of wipings needed. Separately take a sample and repeat the test 5 times, and measure the wear resistance of the coating with the sum of 5 wiping times.

[0040] Anti-corrosion test: The coatings prepared in Examples 1-3 and Comparative Examples 1-3 were sprayed onto the surface of cold-rolled steel plates, vacuum dried, and formed a coating with a thickness of 20 μm. A neutral salt spray test was conducted in accordance with GB / T 10125 standard. The test conditions were: 5wt% NaCl solution, temperature 35°C. After 500h and 1000h, the coating surface condition was rated according to ISO 4628-3 (6 levels in total, 0 for no corrosion, 5 for severe corrosion). Another sample was taken, a cross scratch was made on the coating surface to the substrate, and a neutral salt spray test was conducted again. The test conditions were the same as above, and the single-sided corrosion width at the scratch was tested after 500h and 1000h.

[0041] The obtained data are shown in Table 1.

[0042] Table 1:

Claims

1. A highly wear-resistant and highly anti-corrosive imitation electroplating silver coating, the components of which include surface-modified flaky aluminum powder, cellulose acetate butyrate, acrylate resin, organic solvent, and additives, characterized in that: The surface modified flaky aluminum powder is a flaky aluminum powder coated and modified by a carbon quantum dot / polyurethane interpenetrating cross-linked network material.

2. The electroplating silver-like paint according to claim 1, characterized in that: The mass ratio of the surface modified flaky aluminum powder, cellulose acetate butyrate, polyacrylate resin, organic solvent and additive is 15-25:30-45:5-20:100:0.5-3.

3. The electroplating silver-plating paint according to claim 1, characterized in that: The preparation method of the surface modified flaky aluminum powder is: (1) Add sodium citrate and urea to deionized water and stir to dissolve, pour into a PTFE-lined stainless steel reactor, stir at 200-400 rpm, hydrothermally react at 210-230° C. for 2-4 h, cool, filter, centrifuge and concentrate the supernatant to obtain a carbon quantum dot dispersion; (2) adding isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate into a reaction vessel, stirring at a speed of 100-200 rpm, reacting in a water bath at 50-60° C. for 1-2 hours, and then cooling to room temperature to obtain a viscous polyurethane; (3) mixing the carbon quantum dot dispersion, viscous polyurethane, propylene oxide, acid catalyst, and photoinitiator evenly, and spraying them evenly on the surface of the flaky aluminum powder; (4) First react at 60-80℃ for 8-10h, then age at room temperature for 18-24h, freeze-dry, and then use a UV curing machine to illuminate for 20-30s.

4. The imitation electroplating silver paint according to claim 3, characterized in that: In step (1), the mass ratio of sodium citrate, urea and deionized water is 3-5:8-10:

100.

5. The imitation electroplating silver paint according to claim 3, characterized in that: In step (1), the filtration is performed using filter paper with a pore size of 0.22 μm; the centrifugal speed is 10000-15000 rpm, and the time is 5-20 min; the solid content of the supernatant after concentration is 40-60 wt%.

6. The imitation electroplating silver paint according to claim 3, characterized in that: In step (2), the mass ratio of isophorone diisocyanate, 2,3-dihydroxypropyl acrylate and dibutyltin dilaurate is 100:68-72:1.2-1.

5.

7. The imitation electroplating silver paint according to claim 3, characterized in that: In step (3), the acidic catalyst is HCl or H2SO4; the photoinitiator is composed of TPO-L and 1173 in a mass ratio of 1:0.8-1.

2.

8. The imitation electroplating silver paint according to claim 3, characterized in that: In step (3), the mass ratio of the carbon quantum dot dispersion, the viscous polyurethane, the propylene oxide, the acid catalyst, the photoinitiator, and the flaky aluminum powder is 8-16:20:2-4:0.2-0.4:0.1-0.5:

100.

9. The imitation electroplating silver paint according to claim 1, characterized in that: The thickness of the flaky aluminum powder is 0.1-0.2 μm, and the diameter-to-thickness ratio is 80-120:1; The acrylic resin is one of polymethyl methacrylate, polyethyl methacrylate, polymethyl acrylate and polyethyl acrylate; The organic solvent is composed of solvent A and solvent B in a mass ratio of 1:0.8-1.5, solvent A is one of ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, and hexyl acetate, and solvent B is one of cyclohexanone, cyclopentanone, methyl ethyl ketone, and methyl isobutyl ketone; The auxiliary agent is one or more of a stabilizer, a dispersant, an antioxidant, a leveling agent, and a defoaming agent.

10. The method for preparing the imitation electroplating silver coating according to any one of claims 1 to 9, characterized in that: The specific preparation process is: S1, adding the surface modified flaky aluminum powder into 1 / 3 organic solvent, stirring and dispersing the powder evenly to obtain dispersion A; S2, adding cellulose acetate butyrate, acrylate resin and additives into 2 / 3 organic solvent, stirring and dissolving, to obtain solution B; S3, adding dispersion A into solution B and stirring evenly.

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