Electroplating colorful coating as well as preparation method and coating method thereof

Abstract

The invention provides an electroplating colorful coating as well as a preparation method and a coating method thereof. The electroplating colorful coating comprises the following components in parts by weight: 45-60 parts of organic-inorganic hybrid resin; 15-25 parts of a surface modified colorful effect pigment; 20-30 parts of an environment-friendly composite solvent; 3-5 parts of an adhesion promoter; 2-4 parts of a bio-based composite functional aid; 0.5 to 1.5 parts of a flatting agent; and 0.1 to 0.5 part of a defoaming agent. The electroplating solution has the advantages that through the synergistic effect of a multi-component system, the colorful visual effect superior to that of traditional electroplating and excellent adhesive force are achieved while the environmental protection property is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of electroplating technology, specifically relating to an electroplating iridescent coating and its preparation and application methods. Background Technology

[0002] Surface finishing technology is crucial for enhancing product added value. Among these technologies, electroplating has been widely used in the automotive, hardware, sanitary ware, and consumer electronics industries over the past few decades due to its ability to impart excellent metallic texture, high gloss, and good wear resistance to substrates.

[0003] However, traditional electroplating technology has serious drawbacks that cannot be ignored, mainly in the following two aspects: First, there are serious environmental pollution and health hazards: the electroplating production process involves the use of large quantities of toxic and harmful chemicals such as cyanide, chromium anhydride, and nickel salts, resulting in wastewater and waste residue rich in heavy metal ions. These pollutants are difficult to degrade, causing persistent pollution to water bodies and soil, and directly endangering the health of operators. With increasingly stringent global environmental regulations (such as the EU's RoHS and REACH directives) and the advancement of my country's strategic goals, the traditional electroplating industry, characterized by high pollution and high energy consumption, faces enormous environmental pressure and transformation challenges.

[0004] Secondly, there is the bottleneck problem of insufficient performance of existing alternative technologies: In order to replace traditional electroplating, solutions such as "imitation electroplating coatings" have emerged on the market, but they generally have the following technical pain points that urgently need to be solved: Mediocre visual effects: Most imitation electroplating coatings can only provide a monotonous silver or chrome effect, with dull colors, and cannot achieve a "dazzling" optical effect with depth and layering that changes with the viewing angle, making it difficult to meet the demand for personalized aesthetics in the high-end market.

[0005] Poor adhesion and durability: Especially on non-metallic substrates such as plastics, the coating has weak adhesion to the substrate, making it prone to peeling, scratches, and other problems. Its key indicators such as hardness, weather resistance, and chemical resistance are far inferior to traditional electroplating layers, resulting in short product lifespan and limited application range.

[0006] Incomplete environmental friendliness: Although some coatings claim to use environmentally friendly solvents, the additives (such as certain plasticizers and stabilizers) added to achieve performance may contain substances that are not friendly to human health or the environment, failing to achieve full-chain environmental protection from source to end product.

[0007] Therefore, it is necessary to design an electroplating iridescent coating and its preparation and application methods. Summary of the Invention

[0008] To overcome the shortcomings of the existing technology, an electroplating iridescent coating and its preparation and application methods are provided.

[0009] To achieve the above objectives, the present invention provides the following technical solution: An electroplating iridescent coating comprises the following components in parts by weight: Organic-inorganic hybrid resin: 45-60 parts; Surface-modified iridescent effect pigments: 15-25 parts; Environmentally friendly composite solvent: 20-30 parts; Adhesion promoter: 3-5 parts; Bio-based composite functional additives: 2-4 parts; Leveling agent: 0.5-1.5 parts; Defoamer: 0.1-0.5 parts.

[0010] The organic-inorganic hybrid resin is a silicone-acrylic resin synthesized by the sol-gel method. The specific steps are as follows: acrylate monomer, γ-(methacryloyloxy)propyltrimethoxysilane, and tetraethyl orthosilicate are mixed, an acidic catalyst is added, and the sol-gel reaction is carried out at 60-70°C and under stirring conditions for 5-7 hours to obtain the resin.

[0011] The mass ratio of the acrylate monomer, γ-(methacryloyloxy)propyltrimethoxysilane, and tetraethyl orthosilicate is 100:15-25:5-15; an acidic catalyst, which is hydrochloric acid or p-toluenesulfonic acid, is added at 1%-3% of the weight of the tetraethyl orthosilicate.

[0012] The surface-modified iridescent effect pigment is prepared by the following method: multilayer titanium dioxide-coated mica-based interference pigment is dispersed in ethanol, a silane coupling agent is added, and the mixture is stirred at 65-75°C for 1.5-2.5 hours. The mixture is then filtered, washed with ethanol, and dried at 80°C for 2 hours.

[0013] The mass ratio of the multilayer titanium dioxide-coated mica-based interference pigment, ethanol, and silane coupling agent is 100:200-300:2-3.

[0014] The environmentally friendly composite solvent is composed of dimethyl carbonate and propylene glycol methyl ether acetate in a weight ratio of 1:1-2.

[0015] The adhesion promoter is a phosphonoacrylic acid copolymer with an acid value of 90-110 mg KOH / g.

[0016] The bio-based composite functional additive is a mixture of tea polyphenols and dehydroabsic acid in a weight ratio of 1:1-2.

[0017] A method for preparing an electroplating iridescent coating includes the following steps: adding an organic-inorganic hybrid resin, a surface-modified iridescent effect pigment, an environmentally friendly composite solvent, an adhesion promoter, a bio-based composite functional additive, a leveling agent, and an antifoaming agent into a high-speed disperser and dispersing at 1000-1200 rpm for 30-45 minutes; then transferring the resulting slurry to a sand mill and grinding it to a fineness of less than 15 μm; finally filtering it through a 200-mesh filter to obtain the electroplating iridescent coating product.

[0018] A method for applying electroplated iridescent coating, the method comprising the following steps: i. Substrate pretreatment: After ultrasonic cleaning and degreasing of the plastic substrate and drying, it is treated with low-temperature plasma equipment with a processing power of 800-1000W and a processing time of 60-90 seconds. ii. Coating application: The high-performance environmentally friendly electroplating color coating is loaded into an electrostatic spraying equipment, the spraying voltage is adjusted to 60-70kV and the atomization pressure is 0.3-0.4 MPa, and the coating is applied to the substrate surface after step i, controlling the dry film thickness to be 15-25μm. iii. Step curing: Place the sprayed workpiece in a drying tunnel or oven, first level it at 65℃ for 5-10 minutes, then raise the temperature to 85℃ and hold for 15-20 minutes, and finally force convection baking at 125℃ for 30 minutes to complete the curing.

[0019] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. The electroplating iridescent coating of the present invention utilizes an organic-inorganic hybrid resin as the film-forming material, which combines the flexibility of the organic phase and the high hardness of the inorganic phase at the molecular scale. During the curing process, the siloxane network and organic segments within the resin intertwine to form a dense three-dimensional network structure. This structure not only provides a solid framework for the coating but also enhances its scratch resistance and surface hardness, resulting in a final coating with superior mechanical strength compared to traditional single-system resins.

[0020] 2. The surface-modified iridescent effect pigment selected in this invention involves surface grafting of multilayer titanium dioxide-coated mica-based interference pigments with a silane coupling agent. This treatment transforms the pigment particle surface from hydrophilic to hydrophobic, significantly improving its compatibility with organic-inorganic hybrid resins. During the coating film formation process, the modified pigments can achieve more uniform directional alignment, resulting in brighter, purer interference colors that continuously change with viewing angle, effectively overcoming the hue turbidity problems caused by the agglomeration and blooming of conventional pigments.

[0021] 3. The phosphonoacrylic acid copolymer used in this invention serves as an adhesion promoter. The phosphonic acid groups in its molecular structure exhibit extremely high reactivity with the surface of the plastic substrate. When combined with low-temperature plasma pretreatment, these groups can form strong POC covalent bonds with the active sites on the plastic surface. This strong chemical anchoring effect fundamentally solves the industry problem of poor adhesion between the coating and the plastic substrate, especially polyolefin substrates, ensuring the reliability of the coating during use.

[0022] 4. The environmentally friendly composite solvent system of the present invention is composed of dimethyl carbonate and propylene glycol methyl ether acetate. This composite system has good solubility for organic-inorganic hybrid resins, and its evaporation rate can provide a suitable volatilization gradient after coating, which is beneficial to the leveling and wetting of the coating film and avoids surface defects such as orange peel and pinholes.

[0023] 5. This invention introduces a bio-based composite functional additive composed of tea polyphenols and dehydroabscisic acid. The phenolic hydroxyl group in the tea polyphenol molecule is a natural antioxidant structure that can effectively capture and terminate free radicals generated by the resin under heat and light, thereby inhibiting the aging and yellowing of the coating. Dehydroabscisic acid, with its rigid tricyclic phenanthrene structure, acts like a natural hardener. The two produce a synergistic effect in the system, jointly endowing the coating with excellent anti-aging properties and durability without the need to introduce traditional synthetic additives.

[0024] 6. The preparation method of the present invention disperses the surface-modified iridescent effect pigment with the organic-inorganic hybrid resin under shear force, so that the pigment particles can be stably and persistently suspended in the resin system.

[0025] 7. The step-curing process used in the coating method of this invention allows the solvent to slowly escape and the coating to fully level in the initial low-temperature stage, promotes the initial expansion and cross-linking of resin molecular chains in the medium-temperature stage, and completes the deep curing of the system in the final high-temperature stage. This gradual curing method helps to release internal stress, reduce paint film defects caused by sudden heating, and form a more complete and tough final coating film. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the specific embodiments of this application, the sources of various main raw materials are briefly described as follows: Acrylate monomer: Shanghai Huayi New Materials Co., Ltd. γ-(methacryloyloxy)propyltrimethoxysilane: Hubei Xingyan New Material Technology Co., Ltd. Silane coupling agent KH-792: Shandong Yousuo Chemical Technology Co., Ltd. Dimethyl carbonate, propylene glycol methyl ether acetate, ethyl orthosilicate: Condis Chemical (Hubei) Co., Ltd. Hydrochloric acid: Wuhan Huangpi District Jiangcheng Chemical Co., Ltd. p-Toluenesulfonic acid: Nanjing Huabang New Materials Co., Ltd. is Multilayer titanium dioxide-coated mica-based interference pigment: Hebei Hengguang Mineral Products Co., Ltd. Phosphonoacrylic acid copolymer: Hubei Xingyan New Material Technology Co., Ltd. Tea polyphenols: Shanghai Taoshu Biotechnology Co., Ltd. Dehydroabsic acid: Shandong Jinyueyuan New Materials Co., Ltd. Leveling agents and defoamers: Shanghai Yangshi Industrial Co., Ltd. The technical solution of this application is as follows: An electroplating iridescent coating comprises the following components in parts by weight: Organic-inorganic hybrid resin: 45-60 parts; Surface-modified iridescent effect pigments: 15-25 parts; Environmentally friendly composite solvent: 20-30 parts; Adhesion promoter: 3-5 parts; Bio-based composite functional additives: 2-4 parts; Leveling agent: 0.5-1.5 parts; Defoamer: 0.1-0.5 parts.

[0028] The organic-inorganic hybrid resin is a silicone-acrylic resin synthesized by the sol-gel method. The specific steps are as follows: acrylate monomer, γ-(methacryloyloxy)propyltrimethoxysilane, and tetraethyl orthosilicate are mixed, an acidic catalyst is added, and the sol-gel reaction is carried out at 60-70°C and under stirring conditions for 5-7 hours to obtain the resin.

[0029] The mass ratio of the acrylate monomer, γ-(methacryloyloxy)propyltrimethoxysilane, and tetraethyl orthosilicate is 100:15-25:5-15; an acidic catalyst, which is hydrochloric acid or p-toluenesulfonic acid, is added at 1%-3% of the weight of the tetraethyl orthosilicate.

[0030] The surface-modified iridescent effect pigment is prepared by the following method: multilayer titanium dioxide-coated mica-based interference pigment is dispersed in ethanol, a silane coupling agent is added, and the mixture is stirred at 65-75°C for 1.5-2.5 hours. The mixture is then filtered, washed with ethanol, and dried at 80°C for 2 hours.

[0031] The mass ratio of the multilayer titanium dioxide-coated mica-based interference pigment, ethanol, and silane coupling agent is 100:200-300:2-3.

[0032] The environmentally friendly composite solvent is composed of dimethyl carbonate and propylene glycol methyl ether acetate in a weight ratio of 1:1-2.

[0033] The adhesion promoter is a phosphonoacrylic acid copolymer with an acid value of 90-110 mg KOH / g.

[0034] The bio-based composite functional additive is a mixture of tea polyphenols and dehydroabsic acid in a weight ratio of 1:1-2.

[0035] A method for preparing an electroplating iridescent coating includes the following steps: adding an organic-inorganic hybrid resin, a surface-modified iridescent effect pigment, an environmentally friendly composite solvent, an adhesion promoter, a bio-based composite functional additive, a leveling agent, and an antifoaming agent into a high-speed disperser and dispersing at 1000-1200 rpm for 30-45 minutes; then transferring the resulting slurry to a sand mill and grinding it to a fineness of less than 15 μm; finally filtering it through a 200-mesh filter to obtain the electroplating iridescent coating product.

[0036] A method for applying electroplated iridescent coating, the method comprising the following steps: i. Substrate pretreatment: After ultrasonic cleaning and degreasing of the plastic substrate and drying, it is treated with low-temperature plasma equipment with a processing power of 800-1000W and a processing time of 60-90 seconds. ii. Coating application: The high-performance environmentally friendly electroplating color coating is loaded into an electrostatic spraying equipment, the spraying voltage is adjusted to 60-70kV and the atomization pressure is 0.3-0.4 MPa, and the coating is applied to the substrate surface after step i, controlling the dry film thickness to be 15-25μm. iii. Step curing: Place the sprayed workpiece in a drying tunnel or oven, first level it at 65℃ for 5-10 minutes, then raise the temperature to 85℃ and hold for 15-20 minutes, and finally force convection baking at 125℃ for 30 minutes to complete the curing.

[0037] The present invention will be described in detail below through examples and comparative examples, but the scope of protection of the present invention is not limited to these examples. Unless otherwise specified, the chemical reagents and raw materials used in the following examples and comparative examples are all conventional commercially available products.

[0038] Example 1 An electroplating iridescent coating is prepared as follows: First, an organic-inorganic hybrid resin is prepared by mixing 100g of acrylate monomer, 25g of γ-(methacryloyloxy)propyltrimethoxysilane, and 15g of tetraethyl orthosilicate. Hydrochloric acid (3% by weight of tetraethyl orthosilicate) is added as an acidic catalyst, and the mixture is subjected to a sol-gel reaction at 70°C with stirring for 7 hours to obtain the organic-inorganic hybrid resin. Then, a surface-modified iridescent effect pigment is prepared by dispersing 100g of multilayer titanium dioxide-coated mica-based interference pigment in 300g of ethanol, adding 3g of silane coupling agent (model: KH-792), and stirring at 75°C for 2.5 hours. The mixture is then filtered, washed with ethanol, and dried at 80°C for 2 hours to obtain the modified pigment. Finally, to prepare the coating, weigh 60 grams of the above-mentioned organic-inorganic hybrid resin, 25 grams of surface-modified iridescent effect pigment, 30 grams of environmentally friendly composite solvent composed of dimethyl carbonate and propylene glycol methyl ether acetate in a weight ratio of 1:2, 5 grams of phosphonoacrylic acid copolymer adhesion promoter with an acid value of 110 mg KOH / g, 4 grams of bio-based composite functional additive composed of tea polyphenols and dehydroabsic acid in a weight ratio of 1:2, 1.5 grams of leveling agent, and 0.5 grams of defoamer. Put all of these into a high-speed disperser and disperse at 1200 rpm for 45 minutes. Transfer the resulting slurry to a sand mill and grind it to a fineness of less than 15 μm. Filter the slurry through a 200-mesh filter to obtain the product.

[0039] Example 2 In this embodiment, the similarities to those in Embodiment 1 will not be repeated, and the differences are as follows: An electroplating iridescent coating is prepared as follows: First, an organic-inorganic hybrid resin is prepared by mixing 100g of acrylate monomer, 15g of γ-(methacryloyloxy)propyltrimethoxysilane, and 5g of tetraethyl orthosilicate. 1% (by weight) of p-toluenesulfonic acid is added as an acidic catalyst, and the mixture is subjected to a sol-gel reaction at 60°C with stirring for 5 hours to obtain the organic-inorganic hybrid resin. Then, a surface-modified iridescent effect pigment is prepared by dispersing 100g of multilayer titanium dioxide-coated mica-based interference pigment in 200g of ethanol, adding 2g of silane coupling agent, and stirring at 65°C for 1.5 hours. The mixture is then filtered, washed with ethanol, and dried at 80°C for 2 hours to obtain the modified pigment. Finally, to prepare the coating, weigh 45 grams of the above-mentioned organic-inorganic hybrid resin, 15 grams of surface-modified iridescent effect pigment, 20 grams of environmentally friendly composite solvent composed of dimethyl carbonate and propylene glycol methyl ether acetate in a weight ratio of 1:1, 3 grams of phosphonoacrylic acid copolymer adhesion promoter with an acid value of 90 mg KOH / g, 2 grams of bio-based composite functional additive composed of tea polyphenols and dehydroabsic acid in a weight ratio of 1:1, 0.5 grams of leveling agent, and 0.1 grams of defoamer. Put all of these into a high-speed disperser and disperse at 1000 rpm for 30 minutes. Transfer the resulting slurry to a sand mill and grind it to a fineness of less than 15 μm. Filter the slurry through a 200-mesh filter to obtain the product.

[0040] Example 3 In this embodiment, the similarities to those in Embodiment 1 will not be repeated, and the differences are as follows: An electroplating iridescent coating is prepared as follows: First, an organic-inorganic hybrid resin is prepared by mixing 100g of acrylate monomer, 20g of γ-(methacryloyloxy)propyltrimethoxysilane, and 10g of tetraethyl orthosilicate. Hydrochloric acid (2% by weight of tetraethyl orthosilicate) is added as an acidic catalyst, and a sol-gel reaction is carried out at 65°C with stirring for 6 hours to obtain the organic-inorganic hybrid resin. Then, a surface-modified iridescent effect pigment is prepared by dispersing 100g of multilayer titanium dioxide-coated mica-based interference pigment in 250g of ethanol, adding 2.5g of silane coupling agent, and stirring at 70°C for 2 hours. The mixture is then filtered, washed with ethanol, and dried at 80°C for 2 hours to obtain the modified pigment. Finally, to prepare the coating, weigh 52.5 grams of the above-mentioned organic-inorganic hybrid resin, 20 grams of surface-modified iridescent effect pigment, 25 grams of environmentally friendly composite solvent composed of dimethyl carbonate and propylene glycol methyl ether acetate in a weight ratio of 1:1.5, 4 grams of phosphonoacrylic acid copolymer adhesion promoter with an acid value of 100 mg KOH / g, 3 grams of bio-based composite functional additive composed of tea polyphenols and dehydroabsic acid in a weight ratio of 1:1.5, 1 gram of leveling agent, and 0.3 grams of defoamer. Put all of these into a high-speed disperser and disperse at 1100 rpm for 37.5 minutes. Transfer the resulting slurry to a sand mill and grind it to a fineness of less than 15 μm. Filter the slurry through a 200-mesh filter to obtain the product.

[0041] Comparative Example 1 In this comparative example, the similarities with Example 1 will not be repeated, and the differences are as follows: Instead of using surface-modified iridescent effect pigments, an equal amount of mica-based interference pigments coated with multilayer titanium dioxide without silane coupling agent treatment was used.

[0042] Comparative Example 2 In this comparative example, the similarities with Example 2 will not be repeated, and the differences are as follows: Instead of using an organic-inorganic hybrid resin, an equal amount of ordinary hydroxyl acrylic resin was used.

[0043] Comparative Example 3 In this comparative example, the similarities with Example 3 will not be repeated, and the differences are as follows: No phosphonoacrylic acid copolymer adhesion promoter was used.

[0044] Comparative Example 4 In this comparative example, the similarities with Example 1 will not be repeated, and the differences are as follows: No bio-based composite functional additives were used.

[0045] Comparative Example 5 In this comparative example, the similarities with Example 1 will not be repeated, and the differences are as follows: The coating method did not involve low-temperature plasma treatment; only conventional solvent wiping was performed.

[0046] Performance Test Results and Analysis The performance of the products obtained in the examples and comparative examples was evaluated according to the following general test methods: adhesion test was conducted according to standard GB / T 9286 using the cross-cut test method; hardness test was conducted according to standard GB / T 6739 using a pencil hardness tester; artificial sweat resistance test was conducted according to standard GB / T 32088, with the sample immersed in artificial sweat for 24 hours and the appearance changes observed; salt spray resistance test was conducted according to standard GB / T 10125, with continuous exposure in a neutral salt spray environment for 240 hours; gloss and color effects were characterized using a multi-angle spectrophotometer at a 45° measurement angle; the coating appearance was visually inspected for leveling, orange peel, and pinholes. The specific test results are shown in Table 1.

[0047] The test results show that all three embodiments exhibit excellent and balanced performance in terms of adhesion, hardness, corrosion resistance, gloss, and color uniformity. Embodiment 1, due to its relatively high resin and modified pigment content, demonstrates the most outstanding performance in hardness and gloss. Although Embodiment 2 is slightly lower than the other embodiments in some indicators, it still comprehensively outperforms all comparative examples, proving that the present invention can maintain basic performance even at the lower limit of parameters. Embodiment 3, as a representative of intermediate parameters, shows excellent and balanced performance across all aspects.

[0048] Table 1 Analysis of Test Results

[0049] The results of Comparative Example 1 show that the unmodified iridescent effect pigments exhibit poor dispersibility and compatibility in the resin, leading to decreased coating adhesion, reduced hardness, and slight blooming. This confirms the necessity of pigment surface modification for achieving excellent optical effects and mechanical properties. Comparative Example 2, using ordinary resin, shows a significant decrease in coating hardness, corrosion resistance, and surface leveling, demonstrating the crucial role of the dense network structure formed by the organic-inorganic hybrid resin in improving the overall coating performance. Comparative Example 3, without the use of an adhesion promoter, shows significantly worse adhesion, but other properties are not significantly affected. This highlights the unique contribution of the phosphonoacrylic acid copolymer in enhancing adhesion through chemical bonding with the substrate. Comparative Example 4, without the use of bio-based composite functional additives, shows noticeable yellowing and pitting in the coating, indicating that the synergistic effect of tea polyphenols and dehydroabsic acid is crucial for preventing coating aging and improving corrosion resistance. Comparative Example 5, without plasma treatment, shows a significant decrease in adhesion, demonstrating the importance of substrate pretreatment and adhesion promoters in synergistically improving coating adhesion.

[0050] In summary, the electroplating iridescent coating of the present invention, through the synergistic effect of organic-inorganic hybrid resin, surface-modified iridescent effect pigment, phosphonoacrylic acid copolymer adhesion promoter, bio-based composite functional additive, and matching preparation and coating processes, successfully achieves decorative effects and durability comparable to or even better than traditional electroplating under the premise of environmental protection.

[0051] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An electroplated iridescent paint, characterized in that, The components include the following weight parts: Organic-inorganic hybrid resin: 45-60 parts; Surface modified iridescent effect pigment: 15-25 parts; Environment-friendly composite solvent: 20-30 parts; Adhesion promoter: 3-5 parts; Bio-based composite functional additive: 2-4 parts; Leveling agent: 0.5-1.5 parts; Defoaming agent: 0.1-0.5 parts.

2. The electroplated iridescent paint of claim 1, wherein, The organic-inorganic hybrid resin is a silicone-acrylate resin synthesized by sol-gel method, and the specific steps are as follows: mixing acrylate monomer, γ-(methacryloyloxy) propyl trimethoxysilane and tetraethyl orthosilicate, adding an acidic catalyst, and performing sol-gel reaction at 60-70°C under stirring for 5-7 hours.

3. The electroplated iridescent paint of claim 2, wherein, The mass ratio of the acrylate monomer, γ-(methacryloyloxy) propyl trimethoxysilane and tetraethyl orthosilicate is 100:15-25:5-15; the acidic catalyst accounts for 1%-3% of the weight of the tetraethyl orthosilicate, and the acidic catalyst is hydrochloric acid or p-toluenesulfonic acid.

4. The electroplated iridescent paint of claim 1, wherein, The surface modified iridescent effect pigment is prepared by the following method: dispersing multi-layer titanium dioxide coated mica-based interference pigment in ethanol, adding silane coupling agent, stirring and reacting at 65-75°C for 1.5-2.5 hours, and then filtering, washing with ethanol, and drying at 80°C for 2 hours.

5. The electroplated iridescent paint of claim 4, wherein, The mass ratio of the multi-layer titanium dioxide coated mica-based interference pigment, ethanol and silane coupling agent is 100:200-300:2-3.

6. The electroplated iridescent paint of claim 1, wherein, The environment-friendly composite solvent is obtained by mixing dimethyl carbonate and propylene glycol methyl ether acetate at a weight ratio of 1:1-2.

7. The electroplated iridescent paint of claim 1, wherein, The adhesion promoter is phosphinyl acrylate copolymer, and the acid value is 90-110 mg KOH / g.

8. The electroplated iridescent paint of claim 1, wherein, The bio-based composite functional additive is a mixture of tea polyphenol and dehydroabietic acid at a weight ratio of 1:1-2.

9. A process for the production of the electroplated iridescent coating according to any one of claims 1 to 8, characterized in that, The method includes the following steps: putting the organic-inorganic hybrid resin, surface modified iridescent effect pigment, environment-friendly composite solvent, adhesion promoter, bio-based composite functional additive, leveling agent and defoaming agent into a high-speed disperser, dispersing at a speed of 1000-1200 rpm for 30-45 minutes, then transferring the obtained slurry to a sand mill for grinding to a fineness of less than 15μm, and finally filtering with a 200 mesh filter to obtain the electroplating iridescent coating product.

10. A method of applying the electroplated iridescent coating of any one of claims 1-8, characterized in that, The method includes the following steps: i. Substrate pretreatment: after ultrasonic cleaning and drying of the plastic substrate, a low temperature plasma device is used for treatment, the treatment power is 800-1000W, and the treatment time is 60-90 seconds; ii. Coating application: the high-performance environment-friendly electroplating iridescent coating is loaded into an electrostatic spraying device, the spraying voltage is adjusted to 60-70kV, the atomizing pressure is 0.3-0.4 MPa, and the substrate surface treated in step i is sprayed, and the dry film thickness is controlled to be 15-25μm; iii. Step curing: the sprayed workpiece is placed in a drying channel or oven, first leveled at 65°C for 5-10 minutes, then heated to 85°C for 15-20 minutes, and finally forced convection baked at 125°C for 30 minutes to complete the curing.

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