CN106944322A - Electroless Coating of Substrates - Google Patents

Abstract

The invention provides a product for preparing a multi-layer coating on a substrate by electroless plating and a method thereof.

Description

Electroless Coating of Substrates

technical field

The present invention relates to the application of multilayer coatings on substrates, in particular multilayer coatings deposited on the surface of substrates by electroless plating.

Background technique

One common treatment for metal surfaces is electroplating. However, electroplating is harmful to the global environment by generating large amounts of toxic by-products and waste. And the cost of electroplating is very high. These limit the development of electroplating industry.

Contents of the invention

The present invention provides a substrate having an electroless coating, comprising an adherent coating on the surface of the substrate, the adherent coating comprising a first silicon base coupling agent; a lubricious coating on the lubricious coating comprising epoxy; a silver coating on the lubricious coating comprising silver nanoparticles; and an anti- A scratch-resistant coating comprising a second silicon base coupling agent.

Another method of the present invention provides a method of electroless coating a multi-coating on a substrate comprising a. applying an adherent coating comprising a first silicon base coupling agent to the surface of said substrate; b . applying a slippery coat comprising epoxy resin over said adhesion coat; c. applying a silver coat comprising silver nanoparticles over said slippery coat; d. applying a second silicon base comprising A scratch-resistant coating of coupling agent is coated on top of the silver coating.

Another aspect of the present invention provides a kit for electroless coating on a substrate comprising an adhesive coating solution comprising a first silicon base coupling agent, a slip coating solution comprising an epoxy resin, a base solution comprising silver nitrate An electroless coating solution with a glucose base solution, and an anti-scratch coating solution containing a second silicon base coupling agent.

Description of drawings

Figure 1 shows the interaction of γ-aminopropyltriethoxysilane (A1100) with an epoxy-based adhesion coating according to one embodiment of the present invention.

Figure 2 shows the interaction of the same example of the invention (3-mercaptopropyl)trimethoxysilane (A189) with a silver coating.

Accompanying drawing 3 has shown the result of the decoration test of the same embodiment of the present invention.

Accompanying drawing 4 has shown the result of adhesion test of the sample of the same embodiment of the present invention.

Accompanying drawing 5 has shown the result of anti-corrosion test of the sample of the same embodiment of the present invention.

Accompanying drawing 6 has shown the result of the impact test of the sample of the same embodiment of the present invention.

Accompanying drawing 7 has shown the result of hardness test of the sample of the same embodiment of the present invention.

Accompanying drawing 8 has shown the result of UV irradiation test of the sample of the same embodiment of the present invention.

Accompanying drawing 9 has shown the result of waterproof test of the sample of the same embodiment of the present invention.

Accompanying drawing 10 has shown the result of antacid test of the sample of the same embodiment of the present invention.

Accompanying drawing 11 has shown the result of alkali resistance test of the sample of the same embodiment of the present invention.

detailed description

The present invention provides a decorative product with an electroless multi-coating (ie multi-coating can be achieved without the use of electroplating).

In one embodiment of the present invention, the entire electroless coating process involves three main steps: a base coat coating step, a silver coating coating step, and a scratch-resistant coating coating step. In one embodiment, the thickness of the base coat is 17.5 μm. In another embodiment, the thickness of the silver coating is 90nm. In another embodiment, the scratch-resistant coating has a thickness of 2 μm.

Each step and the materials used are described below.

1. Base coat coating steps

Prior to applying the base coat to the substrate, preparatory steps may optionally be performed on the substrate, ie, surface polishing, surface cleaning and/or surface pretreatment may be performed on the substrate. In one embodiment, the substrate may be a metal substrate.

1.1 Surface pretreatment

In a specific example, the substrate was pretreated with a pretreatment solution made by mixing 8.64 g of Al 100, 750 ml of ethanol, and 31.52 g of deionized water for 10 minutes at room temperature. First, the substrate was contacted with the pretreatment solution and sonicated for 10 minutes at room temperature. Then, the substrate was dried in an oven at 100° C. for 20 minutes, and cooled to room temperature to obtain a pretreated substrate.

1.2. Composition of Adhesive Coating Solution and Smooth Coating Solution

The base coat consists of two primary coats: an adherent coat and a smooth coat. The adhesion coating is first applied to the surface of the substrate to enhance the adhesion of the base coating to the substrate and to provide corrosion protection to the coated substrate. A slip coat is then applied over the adhesion coat to enhance the slip of the base coat to enhance the adhesion of the base coat to the silver coat.

The compositional ranges of the adhesion coating solution and the smooth coating solution are listed in Tables 1A and 2A, respectively.

Table 1A Composition range of adhesion coating solution

composition Weight % Range Epoxy E-51 28.99%-32.04% BYK-361N 0.23%-0.26% ethanol 6.96%-7.69% acetone 54.46%-60.19% TZ-550 4.36%-4.81%

Table 2A Composition range of smooth coating solution

In a particular embodiment, the compositions of the adhesive coating solution and the slippery coating solution are listed in Tables 1B and 2B, respectively.

Table 1B Composition of Adhesive Coating Solution

Table 2B Composition of smooth coating solution

composition weight% Epoxy resin E-51 44.17% BYK-361N 0.40% CGE 5.80% acetone 4.66% diacetone alcohol 24.98% Butanol 12.49% TZ-550 7.50%

In one embodiment, acetone in the adherent coating solution or slippery coating solution acts as a solvent and can be increased to 90% of the volume of the adherent coat solution or slippery coat solution.

Additionally, different weight ratios of the solvent (ie, acetone) in the adhesive coating solution and the slippery coating solution result in different evaporation rates for the two coating solutions.

1.2.1 Preparation of Adhesive Coating Solution

In a particular embodiment, the adhesive coating solution includes an adhesive stock solution and a curing agent solution. First, an adhesion stock solution (1 kg) was prepared by mixing 713.05 g of epoxy resin E-51, 171.15 g of acetone, and 115.8 g of ethanol at room temperature until a uniform solution was formed. A curing agent solution (1 kg) was prepared by mixing 33.90 g BYK-361N, 636.80 g TZ-550, and 329.30 g ethanol at room temperature until a homogeneous solution was formed.

Thereafter, 342.4 g of the adhesive original solution, 400.0 g of acetone, and 57.6 g of the curing agent solution were mixed at room temperature for 3 minutes, and then subjected to ultrasonic waves in a water bath for 10 minutes, thereby obtaining an adhesive coating solution.

1.2.2 Preparation of smooth coating solution

In a particular embodiment, the slip coating solution includes a slip stock solution and TZ-500. First, the smooth stock solution (1kg) was mixed with 477.55g epoxy resin E-51, 135.05g n-butanol, 270.10g diacetone alcohol, 50.35g acetone, 62.65g CGE and 4.30g BYK-361N at room temperature until a homogeneous solution was formed And made.

Afterwards, 925.0 g of the original smooth solution and 75.0 g of TZ-550 were mixed at room temperature for 3 minutes, and then ultrasonicated in a water bath for 10 minutes to obtain a smooth coating solution.

1.3 Coupling agent A1100

Coupling agent A1100 was added to the adhesion coating solution to enhance the adhesion of the epoxy-based adhesion coating to the substrate surface. This enhanced adhesion is due to the interaction of the NH groups of A1100 with the O groups of the epoxy resin resulting in a strong combination of these two functional groups, as shown in Figure 1.

1.4 Adhesive coating applied to the substrate

The adhesive coating solution prepared above was first degassed by ultrasonication over 5 minutes. Adhesive coating solutions are applied to substrates by brushing, dipping or spraying. The coated substrate was cured by heating at 150°C for 15 minutes.

In a particular embodiment, the adhesive coating solution is sprayed onto the substrate as follows. First, deionized water was sprayed on the substrate at a rate of 22 mL/min and a pressure of 3 bar. Then, acetone was sprayed on the substrate followed by the adhesive coating solution sprayed on the substrate for 30 seconds with the spray gun approximately 15 cm from the substrate. The coated substrate was cured by heating at 150°C for 15 minutes.

1.5 Smooth coating applied to substrate coated with adhesive coating

The lubricious coating solution prepared above was first degassed by ultrasonication over 10 minutes. The slip coat solution is applied to the adherent coat by brushing, dipping or spraying. The coated substrates were coated at 80°C for 3-6 hours.

In a particular embodiment, the slip coating solution is sprayed onto the substrate as follows. First, deionized water was sprayed on the substrate at a rate of 55 mL/min and a pressure of 3 bar. Then, acetone was sprayed on the substrate, followed by a smooth coating solution sprayed on the substrate for 30 seconds with the spray gun approximately 15 cm from the substrate. The coated substrate is hardened by heating at 80°C for 3-6 hours.

2 Silver coating coating steps

In this step, silver is electrolessly coated on the base coat by a redox reaction in which silver ammonium complex [Ag(NH ₃ ) ₂ ] ⁺ reacts with glucose as a reducing agent.

2.1 Electroless coating solution

The electroless coating solution included two solutions, a silver nitrate base solution and a glucose base solution, the composition ranges of which are shown in Table 3.

The composition of table 3 silver nitrate base solution and glucose base solution

In one embodiment, the concentration range of silver nitrate in the silver nitrate base solution is 7.5-20 g/L. In another embodiment, the concentration range of glucose in the glucose base solution is 5-20 g/L.

2.1.1 Preparation of silver nitrate base solution

In a specific embodiment, a silver nitrate base solution is prepared as follows. Sodium hydroxide solution was obtained by mixing 6.00 g of sodium hydroxide and 20 mL of deionized water at room temperature until all solids were dissolved. 10 g of silver nitrate and 100 mL of deionized water were mixed at room temperature until all solids were dissolved to obtain a silver nitrate solution. Sodium hydroxide solution was added to the silver nitrate solution until a brown precipitate formed. 30 mL of 28% ammonia water was mixed with 60 mL of deionized water to obtain an ammonia solution. Aqueous ammonia solution was added dropwise to the sodium hydroxide and silver nitrate mixture until all brown precipitate just redissolved to obtain a clear solution. The clear solution was finally diluted to 1 L with deionized water to obtain a silver nitrate base solution.

2.1.2 Preparation of glucose base solution

In a specific example, a glucose base solution is prepared by mixing 8.00 g of glucose, 0.54 g of citric acid, 20 mL of ethanol, and 980 mL of water at room temperature until a homogeneous solution is formed.

2.1.3 Preparation of sensitization solution

In a specific example, 4.00 g of SnCl ₂ (stannous chloride) and 4 mL of 37% hydrochloric acid were mixed, and the mixture was heated at 60° C. for 10 minutes until a clear solution was formed. A sensitized solution was obtained by adding 800 mL of deionized water to the clear solution at room temperature.

2.2 Silver coating is coated on the substrate with base coating

2.2.1 Cleaning

The substrate coated with the base coat was washed with flowing acetone and ethanol (volume ratio 1:1) for 1 minute, and then with deionized water for 1 minute. The cleaning of the epoxy-based base coat not only removes unreacted epoxy residues, but also roughens the epoxy surface to improve the mechanical interlocking of Sn ions and silver to adhere to the ring in later steps. epoxy surface.

2.2.2 Sensitization

In this step, the cleaned and dried substrate was contacted with a stannous chloride solution, and then the substrate was washed with flowing deionized water, dried in an oven at 90°C, and cooled to room temperature in air.

The stannous chloride acts as a sensitizer to enhance the adhesion of the silver to the epoxy surface of the base coat. In one embodiment, the stannous chloride is oxidized (eg, air oxidized for 1 day) before being applied to the substrate. The inventors found that once oxidized (or aged), some of the Sn ²⁺ will oxidize to Sn ⁴⁺ and the resulting mixture of Sn ²⁺ and Sn ⁴⁺ adheres to silver and epoxy resins better than only Sn ²⁺ The "fresh stannous chloride" has a better enhancement effect.

In a particular embodiment, the sensitizing fluid is sprayed onto the substrate as follows. First, deionized water was sprayed on the substrate at a rate of 10 mL/min and a pressure of 3 bar. Then, the sensitizing solution was sprayed on the substrate for 30 seconds with the spray gun at a distance of about 5 cm from the substrate.

2.2.3 Silver coating applied to the substrate

After sensitization, silver nitrate base solution and glucose base solution were simultaneously cross-sprayed on the sensitized substrate for 0.5 min at room temperature. When cross-sprayed, the particles of the silver nitrate base solution and the glucose base solution will form a fine evaporated form before contacting the surface of the sensitized substrate. Thus, a homogeneous layer of silver nanoparticles (approximately 30-150 nm particle size) can be cross-sprayed on a substrate to produce a product with the same or better shine than electroplated silver. Afterwards, the substrate was washed with deionized water and dried in an oven at 100°C for at least 15 minutes.

In one embodiment, the spray rate of the silver nitrate base solution and the glucose base solution is 3:2 to 1:3 (for example, 12mL/min: 8mL/min, 8mL/min: 8mL/min, 8mL/min: 12mL/min , 8mL/min: 16mL/min, or 8mL/min: 24mL/min, etc.).

In another embodiment, the concentration of silver nitrate base solution is 10g/L; the concentration of glucose base solution is 8g/L; the spray rate of silver nitrate base solution is 10mL/min; the spray rate of glucose base solution is 20mL/min .

In another specific embodiment, the silver nitrate base solution and the glucose base solution are sprayed on the substrate as follows. First, the sensitized substrate was rinsed with deionized water for 1 min, and then using a double-headed spray gun, deionized water was sprayed on the substrate at a rate of 10 mL/min through the first nozzle, and deionized water was passed through the second nozzle at a rate of 20 mL/min. Spray the substrate with the dual spray guns about 40cm away from the substrate. Afterwards, the silver nitrate base solution and the glucose base solution were simultaneously sprayed on the substrate by the first and second nozzles for 60 seconds, the first nozzle was sprayed on the substrate at a rate of 10mL/min, and the second nozzle was sprayed at a rate of 20mL/min. Substrate, the distance between the dual spray guns is about 40cm from the substrate. The coated substrate was rinsed with deionized water for 1 minute, dried in compressed air for 30 seconds, heat cured at 100°C for 15 minutes, and cooled to room temperature.

2.2.4 Antioxidant treatment

Silver coated substrates can optionally be treated to enhance anti-oxidative effects. In this step, the substrate was contacted with the anti-oxidant solution at 40°C for 5 minutes, the substrate was then washed with deionized water more than 3 times and dried at room temperature.

2.3 Glucose as reducing agent

US 4,737,188 (the '188 patent) describes the instability of perreducing agents in the use of electroless coatings, where hydrogen is released and/or reducing sugars are degraded into precipitates or other by-products. In addition, invert sugar as a reducing agent requires higher temperatures for effective silver deposition. For example, the '88 patent discusses that silver deposition below 43-54°C does not work well and is costly.

In the present invention, the inventors successfully utilized glucose as a reducing agent to effectively deposit a uniform layer of silver nanoparticles on the epoxy surface of the substrate. And the deposition process of the silver layer (ie the spraying process) is carried out at room temperature, which is much lower than the temperature required by the '188 patent.

3 Scratch-resistant coating coating steps

In this step, a silicon-containing scratch-resistant coating is applied over the silver coating to enhance the scratch resistance of the coated substrate.

3.1 Composition of scratch-resistant coating solution

The compositional ranges of the scratch-resistant coating solutions are listed in Table 4A.

The composition scope of table 4A anti-scratch coating solution

In a particular embodiment, the composition of the scratch resistant coating solution is listed in Table 4B.

The composition of table 4B anti-scratch coating solution

composition weight% MTMS 34.57% A189 4.00% Butanol 12.04% Acetic acid 1.21% Deionized water 13.65% 3% silica gel 1.21% diacetone alcohol 33.32% purple crystal 0.01%

3.1.1 Preparation of scratch-resistant coating solution

In a specific example, 36.0 g of A189, 311.2 g of MTMS, 122.9 g of deionized water, 10.8 g of acetic acid, 108.3 g of n-butanol, and 10.8 g of 3% silica gel were mixed at room temperature for 15 minutes, and the resulting solution was sonicated in a water bath for 45 minutes, Heat at 70°C for 10 hours and cool to room temperature. Then 0.11 g of crystal violet and 300 g of diacetone alcohol were added to the cooled solution to obtain a scratch-resistant coating solution.

3.2 Coupling agent A189

A189, the chemical structure of (3-mercaptopropyl) trimethoxysilane is shown in the following formula (I)

(I)

When the anti-scratch coating is applied to the silver coating, the coupling agent A189 is mixed with the silicon-based anti-scratch coating solution and applied on the silver coating to enhance the adhesion of the silicon-based anti-scratch coating to the silver coating. This enhanced adhesion is due to the strong bond formed by the interaction between the SH groups of A189 and the silver surface of the silver coating, as shown in Figure 2.

3.3 Crystal Violet

If desired, crystal violet can be added to the scratch resistant coating solution to improve the appearance of the coated product. In particular, the addition of crystal violet removes the yellowish side effect of the silver surface of the silver coating.

3.4 Anti-scratch coating coated on silver-coated substrate

The silver-coated substrate was contacted with the above scratch-resistant coating solution for more than 1 minute, the substrate was heated at 100°C for more than 18 hours, and then treated at 150°C for 3 hours to obtain a multi-coated substrate.

In a particular embodiment, the scratch resistant coating solution is sprayed on the substrate in the following manner. First, deionized water was sprayed on the substrate at a rate of 8 mL/min and a pressure of 3 bar, and then the scratch-resistant coating solution was sprayed on the substrate for 35 seconds. The spray gun was about 15 cm away from the substrate, and the sprayed substrate was heated and hardened at 150 ° C for 3 hours.

4 sample test

The decorative product (electroless plated sample) prepared by the above method was compared with the product coated with silver by electroplating (electroplated sample). Metal substrates for the electroless and plated samples were steel Q-195A and/or zinc alloy #3.

4.1 Decoration test

The angular reflectance of electroless plated samples and electroplated samples at 45 degrees 380-780 nm was measured with a UV-Vis spectrophotometer. As shown in Figure 3, the electroless sample has a higher angular reflection than the plated sample. The reflection area of the electroless sample was 26,264 and that of the plated sample was 17,911. Therefore, the electroless plated sample has a better decorative effect than the plated sample.

4.2 Adhesion test

The ASTM D3359-08 standard test method for measuring adhesion with reference to ISO2409:2007 Paint and varnish adhesive tape test was adopted (cross cut test). The results shown in Figure 4 show that the electroless plated sample has no fragments falling off, reaching the 5B standard (0% of the test area falls off), indicating that the test area does not fall off, which is better than the 4B standard (with less than 5% of the test area falling off). Therefore these coatings, especially silver coatings, were not easily peeled off from the electroless plated samples.

4.3 Anti-corrosion test

Referring to ISO 9227:2006 Corrosion test in artificially conditioned air, the ASTM B117-07 standard method for operating a salt spray (Fog) apparatus was adopted (Salt spray test - 72 hours without corrosion). The results shown in Figure 5 show no visible changes for the electroless plated samples. The electroless plated samples therefore exhibit corrosion resistance.

4.4 Impact test

The ASTM D2794-93 (2004) standard test method for resistance to rapid deformation of organic coatings was adopted (steel ball impact - no visible cracks). As shown in Figure 6, the electroless sample had no visible cracks. Therefore, it is shown that the electroless plated samples are not easily deformed.

4.5 Hardness test

Referring to ISO 15184:1998, ASTM D3363-05 standard test method for hardness of paint film with pencil for paint and clear painting is adopted (pencil test - ≥ 2 hours). The results shown in Figure 7 indicate that the electroless sample lasted for 3-4 hours of this test. Therefore, it is shown that the surface of the electroless plated sample is scratch-resistant.

4.6 RoHS directive test

This test is carried out with reference to Hong Kong General Testing and Certification Co., Ltd. IEC62321:2008. As shown in Table 5, Cd, Pb, Hg, Cr(VI), PBBs, and PBDE were not detected in the electroless samples. The electroless samples also had no detectable toxic heavy metals or hydrocarbons and are therefore environmentally friendly.

Table 5 RoHS Directive Tests for Electroless Plated Samples

4.7UV irradiation test

Referring to ISO4892-3, ASTM G154-04 Standard Method for Fluorescent Lamp Apparatus for UV Irradiation of Non-Metallic Materials and Exposure Mode 1/2 was adopted. There was no visible color change in the electroless sample as shown in Figure 8. The coatings of the electroless samples therefore exhibit protection against UV light.

4.8 Waterproof test

In this test, electroless plated samples were soaked in water at 40°C for 24 hours. As shown in Figure 9, the electroless plated samples had no visible color change. Therefore, it is shown that the electroless plated samples are waterproof.

4.9 Antacid test

In this test, electroless plated samples were soaked in 0.1N sulfuric acid at room temperature for 24 hours. As shown in Figure 10, the electroless plated sample had no visible color change. Thus it was shown that the electroless plated samples were acid resistant.

4.10 Alkali resistance test

In this test, electroless plated samples were soaked in 0.1N NaOH at room temperature for 24 hours. As shown in Figure 11, the electroless plated samples had no visible color change. Thus it was shown that the electroless plated samples were alkali resistant.

Exemplary embodiments of the present invention have thus been fully described. Although the specification refers to specific embodiments, it will be apparent to those skilled in the art that the invention may be practiced with variation of these specific details. Accordingly, the invention should not be construed as limited to the embodiments set forth herein.

For example, acetone can be used as a solvent in the method of the present invention, but those skilled in the art know that other chemical reagents such as methanol, benzene, triethylamine, acetic acid, chlorobenzene, phenol and quinolones can also be used.

Moreover, those skilled in the art will appreciate that the spraying time may vary depending on various factors, such as the substrate being sprayed and the spraying environment, and the like.

Claims (16)

1. A substrate having an electroless coating, comprising an adherent coating on the surface of said substrate, said adherent coating comprising a first silicon base coupling agent; an adhesive coating on said adherent coating a smooth coating comprising epoxy resin; a silver coating on said smooth coating, said silver coating comprising silver nanoparticles; and a scratch-resistant coating on said silver coating coating, the scratch-resistant coating comprising a second silicon base coupling agent. 2. The substrate of claim 1, wherein said first silicon base coupling agent is gamma-aminopropyltriethoxysilane; said second silicon base coupling agent is (3-mercaptopropyl)trimethyl Oxysilane. 3. A method of electroless coating a multi-coating on a substrate, comprising: a. applying an adhesive coating comprising a first silicon-based coupling agent to the surface of the substrate; b. applying a lubricious coating comprising epoxy resin over the adhesive coating; c. coating a silver coating comprising silver nanoparticles on the smooth coating; d. Applying a scratch resistant coating comprising a second silicon base coupling agent over the silver coating. 4. The method of claim 3, wherein the first silicon-based coupling agent is γ-aminopropyltriethoxysilane; the second silicon-based coupling agent is (3-mercaptopropyl) trimethoxy base silane. 5. The method of claim 3, step a further comprising i. Spray deionized water on the substrate at a rate of 22mL/min and a pressure of 3bar; ii. Spray acetone on the substrate, followed by spraying the adhesive coating solution on the substrate for 30 seconds with the spray gun approximately 15 cm from the substrate; and iii. The coated substrate obtained in step ii was hardened by heating at 150° C. for 15 minutes to form the adherent coating on the substrate. 6. The method of claim 3, step b further comprising i. Deionized water is sprayed on the substrate at a rate of 55mL/min and a pressure of 3bar; ii. Spray acetone on the substrate, and then spray the smooth coating solution on the substrate for 30 seconds with the spray gun about 15cm away from the substrate; iii. Heat hardening the coated substrate obtained in step ii at 80° C. for 3-6 hours to form the smooth coating on the adherent coating of the substrate. 7. The method of claim 3, step c further comprising i. contacting the coated substrate of step b with a sensitizer; ii. Dry the sensitized substrate at 90°C, and cool the dried substrate to room temperature in air; iii. Simultaneously cross-spraying silver nitrate base solution and glucose base solution on the sensitized substrate to form a layer of silver nanoparticles on the cooled substrate; and iv. Harden the coated substrate of step iii by heating in a 100°C oven for at least 15 minutes. 8. The method of claim 3, step c further comprising i. contacting the coated substrate of step b with a sensitizer; ii. Dry the sensitized substrate at 90°C, and cool the dried substrate to room temperature in air; iii. Rinse the sensitized substrate with deionized water for 1 minute; iv. Use a double-headed spray gun. The silver nitrate base solution is sprayed on the substrate at a rate of 10mL/min through the first spray nozzle, and the glucose base solution is sprayed on the substrate at a rate of 20mL/min through the second spray nozzle. The distance between the two spray guns is about 40cm from the substrate. 60 seconds; v. Wash the substrate with deionized water for 1 minute, dry in compressed air for 30 seconds, heat and harden at 100° C. for 15 minutes, and then cool to room temperature to form a layer of silver nanoparticles. 9. The method of claim 7 or 8, wherein the sensitizer comprises a mixture of Sn2 ⁺ and Sn4 ⁺ . 10. The method of claim 7 or 8, wherein the silver nanoparticles have a size of 30-150 nm. 11. The method of claim 4, wherein step d further comprises i. Deionized water is sprayed on the substrate at a rate of 8mL/min and a pressure of 3bar; ii. Spray the anti-scratch coating solution on the substrate for 35 seconds, the spray gun is about 15cm away from the substrate, and the sprayed substrate is heated and hardened at 150°C for 3 hours, thereby forming the anti-scratch coating on the silver coating of the substrate Floor. 12. A kit for electroless coating on a substrate, comprising an adhesive coating solution containing a first silicon base coupling agent, a smooth coating solution containing an epoxy resin, a base solution containing silver nitrate, and a glucose base solution The electroless coating solution, and the anti-scratch coating solution containing the second silicon-based coupling agent. 13. The kit of claim 12, said adhesive coating solution comprising 28.99%-32.04% (w/w) Epoxy E-51, 0.23%-0.26% (w/w) BYK-361N, 6.96 %-7.33% (w/w) ethanol, 54.46%-60.19% (w/w) acetone, and 4.36%-4.81% (w/w) TZ-550. 14. The kit of claim 12, the smooth coating solution comprising 41.96%-46.38% (w/w) Epoxy E-51, 0.22%-0.57% (w/w) BYK-361N, 5.77% -5.82% (w/w) glycidyl 2-methylphenyl ether, 4.39%-4.93% (w/w) acetone, 23.82%-26.15% (w/w) diacetone alcohol, 9.37%-15.61% (w/w) n-butanol, and 6.56%-8.44% (w/w) TZ-550. 15. The kit of claim 12, said silver nitrate base solution comprising deionized water, sodium hydroxide, silver nitrate and 28% ammonia water; said glucose base solution comprising glucose, citric acid, ethanol and deionized water. 16. The kit of claim 12, said scratch-resistant coating comprising 33.88%-35.26% (w/w) trimethoxymethylsilane, 3.92%-4.08% (w/w) (3-mercaptopropyl ) trimethoxysilane, 11.80%-12.28% (w/w) n-butanol, 13.61%-13.69% (w/w) deionized water, 1.18%-1.23% (w/w) 3% silica gel, 32.66% - 33.99% (w/w) diacetone alcohol, and 0.01% - 0.02% (w/w) crystal violet.