Alkali-resistant silver paint and preparation method thereof

Abstract

The invention discloses a preparation method of an alkali-resistant silver coating, which comprises the following steps: (1) adding pretreated aluminum powder into a solvent, and then adding chitosan and inorganic metal salt for reaction to prepare chitosan and metal salt coated aluminum powder; the preparation method comprises the following steps: adding a template agent and carbon microspheres into an alkali solution, uniformly dispersing, adding organic silicate ester into an obtained mixture, and reacting to obtain silicon dioxide extinction powder; adding the prepared silicon dioxide matting powder and a modifier into toluene for reflux reaction to prepare surface-modified silicon dioxide matting powder; the preparation method comprises the following steps: uniformly mixing the chitosan with the metal salt coated aluminum powder, the surface modified silicon dioxide matting powder, the accelerant, the flame retardant, the auxiliary agent and the filler, feeding into an extruder for melt extrusion, cooling after extrusion, crushing and sieving to obtain the alkali-resistant silver coating. A coating prepared from the alkali-resistant silver paint provided by the invention on a metal surface can keep stable color and complete in a strong alkaline environment.

Description

Technical Field

[0001] The present invention belongs to the field of coatings, and in particular relates to an alkali-resistant silver coating and a preparation method thereof. Background Art

[0002] Silver coatings are a type of multifunctional coatings that are highly favored for their unique qualities and wide applicability. With their bright appearance and excellent reflective properties, silver coatings are widely popular in numerous projects in the industrial and artistic fields. Specifically, silver coatings can present a realistic silver metallic effect, thus becoming an ideal choice for enhancing the visual appeal of surfaces and objects, which can add refinement and elegance to various designs. In addition, the reflective characteristics of silver coatings make them an ideal material for reflecting light, especially suitable for scenarios where light reflection needs to be enhanced; this includes not only providing protective coatings for surfaces exposed to harsh environments, but also decorative embellishments and automotive topcoats and other applications. Generally speaking, silver coatings not only have a beautiful appearance and significant reflective effects, but also can adapt to outdoor environments and withstand the tests of moisture, ultraviolet rays and other environmental factors. Therefore, the versatility and flexibility of silver coatings make them extremely widely used, not only for protecting industrial equipment, but also for adding metallic luster to furniture, and can also be used to create visually impactful artworks.

[0003] Currently, silver coatings on the market are mainly composed of pigments, resins, solvents and additives, etc., and are used for various decorative and protective purposes. However, these coatings tend to have problems such as color darkening, coating peeling or performance degradation in an alkaline environment, which limits their applications in certain specific fields, such as occasions that often come into contact with alkaline substances like building exterior walls and industrial equipment. Therefore, it is very necessary to develop an alkali-resistant silver coating with better performance. Summary of the Invention

[0004] The purpose of the present invention is to provide an alkali-resistant silver coating and a preparation method thereof.

[0005] To achieve the above purpose, the solution of the present invention is:

[0006] A preparation method of an alkali-resistant silver coating, comprising the following steps:

[0007] (1) Add the pretreated aluminum powder into a solvent, and then add chitosan and inorganic metal salts to react to obtain aluminum powder coated with chitosan and metal salts;

[0008] (2) Add the templating agent and carbon microspheres into an alkaline solution, disperse them evenly, and then add organosilicate to the obtained mixture to react to obtain silica matting powder;

[0009] (3) Add the silica matting powder and modifier prepared in step (2) to toluene and carry out a reflux reaction to obtain the surface-modified silica matting powder;

[0010] (4) Mix the chitosan prepared in step (1), the aluminum powder coated with metal salt, the surface-modified silica matting powder prepared in step (3), the accelerator, the flame retardant, the auxiliary agent and the filler evenly, and then send them into an extruder for melt extrusion. After extrusion and cooling, pulverize and screen to obtain the alkali-resistant silver paint.

[0011] Preferably, the particle size of the aluminum powder in step (1) is 1 to 10 microns.

[0012] Preferably, the chitosan in step (1) is modified chitosan.

[0013] Preferably, the inorganic metal salt in step (1) is one of iron salt, chromium salt, nickel salt or cobalt salt.

[0014] Preferably, the template agent in step (2) is one of cetyltrimethylammonium bromide, dodecyltrimethylammonium bromide, polyoxyethylene (20) lauryl ether or cetyltrimethylammonium hydroxide.

[0015] Preferably, the organic silicate in step (2) is one of tetraethyl orthosilicate or isopropyl orthosilicate.

[0016] Preferably, the modifier in step (3) is one of methacryloxypropyltrimethoxysilane, isopropyltri(dioctylpyrophosphate acyl) titanate, stearic acid, lauric acid or oleic acid.

[0017] Preferably, the saturated polyester resin in step (4) is one of 345 saturated polyester, 301B saturated polyester or 385 saturated polyester; the amino resin is one of CYMEL303LF, CYMEL308 or CYMEL327 type amino resins; the accelerator is one or more of PCA-302 silane coupling agent, BYK-3941P adhesion promoter or L216 accelerator; the flame retardant is composed of one or a mixture of two of aluminum hydroxide or magnesium hydroxide; the auxiliary agent is hydroxyalkylamide; the filler is calcium carbonate powder.

[0018] The silver paint prepared by the foregoing preparation method of the alkali-resistant silver paint comprises the following components in parts by weight:

[0019] Saturated polyester resin 50-55 parts;

[0020] Amino resin 10-18 parts;

[0021] Accelerator 0.5-1 part;

[0022] 1 - 2 parts of flame retardant;

[0023] 3 - 5 parts of surface - modified silica matting powder;

[0024] 5 - 8 parts of aluminum powder coated with chitosan and metal salt;

[0025] 2 - 3 parts of auxiliary agent;

[0026] 3 - 5 parts of filler.

[0027] Application of the aforementioned alkali - resistant silver paint in the anti - corrosion of metal materials.

[0028] The specific principle of the preparation method of the alkali - resistant silver paint provided by the present invention is as follows:

[0029] The preparation method of the alkali - resistant silver paint provided by the present invention first pre - treats the aluminum powder raw material by cleaning and surface activation treatment, which can improve its bonding force with the subsequent coating layer; then uses modified chitosan combined with inorganic metal salts to coat the aluminum powder to form a uniform and dense modified chitosan - metal ion complex layer, and this coating layer can mainly play the role of isolating the external alkaline environment; here, it mainly utilizes the characteristic that modified chitosan and metal ions are prone to complex reaction and quickly deposit on the surface of the aluminum powder substrate. In addition, the surface - modified silica matting powder used in the present invention is prepared by the sol - gel method combined with a dual - template agent. Here, the surface modification of silica further enhances its bonding force with the matrix after forming the paint; through chemical modification, organic or inorganic functional groups can be introduced on the surface of silica to form a tighter chemical bond (such as Metal - O - Si bond), thereby further improving the anti - corrosion effect of the coating. Finally, the present invention also optimizes the resin system used, mainly using resins with excellent alkali - resistance performance, such as saturated polyester resin and polyurethane resin, etc., further improving the adhesion and corrosion - resistance performance of the paint.

[0030] Compared with the existing silver paint and its preparation method, the beneficial effects of the present invention are as follows:

[0031] 1. The preparation method of the alkali - resistant silver paint provided by the present invention is not only simple to operate, has mild conditions, but also has good repeatability and scalability, and is very suitable for large - scale industrial production. This method provides an innovative way for the production of alkali - resistant silver paint and opens up a new idea for the development of related fields.

[0032] 2. The coating made of the alkali - resistant silver paint provided by the present invention on the metal surface not only has excellent alkali - resistance, can maintain color stability and coating integrity even in a strong alkaline environment, but also has high mechanical properties and good high - temperature resistance. Specific embodiments

[0033] The present invention will be further described in detail below in conjunction with embodiments. It should also be understood that the following embodiments are only used to further illustrate the present invention and cannot be construed as limiting the protection scope of the present invention. The specific quality, reaction time and temperature, process parameters, etc. in the examples are also only an example within a suitable range. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the protection scope of the present invention.

[0034] The reagents used in the embodiments of the present invention are all commercial reagents unless otherwise specified and have not been further purified before use.

[0035] The aluminum powder raw material used in the embodiments of the present invention needs to be pretreated before use. The specific steps are as follows: Take 100 g of high-purity aluminum powder, add it to 500 ml of ethanol, stir for 10 minutes, and filter to remove ethanol; then, add the washed aluminum powder to 500 ml of a phosphoric acid solution with a concentration of 2.5%, heat to 60 °C, stir for 30 minutes, filter to remove the phosphoric acid solution, wash with deionized water until neutral, and then dry for standby.

[0036] The chitosan used in the embodiments of the present invention needs to be modified before use. The specific steps are as follows:

[0037] First, weigh 5 g of chitosan, add it to 600 ml of methanol, and stir evenly. Subsequently, add 1.5 ml of an aqueous glutaraldehyde solution with a mass fraction of 25%, and stir the mixture at 50 °C for 8 hours. After the reaction is completed, collect the solid product by filtration, and dry the collected solid in a vacuum drying oven at 60 °C for 10 hours to obtain cross-linked chitosan. Then, add the above cross-linked chitosan to 250 ml of an aqueous sodium hydroxide solution with a concentration of 0.2 mol / L, stir evenly, and add 10 ml of carbon disulfide. Stir the resulting mixture at 45 °C for 5 hours. After the reaction is completed, collect the solid product by filtration, wash the solid with distilled water until neutral, and then wash it twice with anhydrous ethanol (100 ml each time). Finally, place the washed solid in a vacuum drying oven and dry it at 50 °C for 10 h to obtain modified chitosan.

[0038] Example 1:

[0039] The preparation steps of the alkali-resistant silver paint are as follows:

[0040] (1) Add 1.5 g of pretreated aluminum powder to a mixed solvent composed of 150 mL of absolute ethanol and 100 mL of Tris-HCl buffer solution (concentration 0.01 M, pH value 8.5). Then, add 0.6 g of modified chitosan and 0.2 g of ferric chloride under stirring. Continue to stir the obtained mixture at room temperature for 0.5 h. After the reaction, filter by suction. Wash the obtained precipitate three times with absolute ethanol (100 mL each time). Then, place the obtained solid in an 80 °C drying oven and dry for 24 h to obtain aluminum powder coated with modified chitosan and metal salt.

[0041] (2) Add 1.5 g of the template agent cetyltrimethylammonium bromide to a mixed solvent composed of 450 mL of absolute ethanol and 50 mL of deionized water. Then, add 15 mL of an ammonia water solution with a mass concentration of 25% to obtain a mixed solution. Add 2 g of carbon microspheres (particle size range 10 - 20 microns) to the prepared mixed solution. After dispersing evenly, add NaOH solution (1 mol / L) to the obtained mixture to adjust the pH value of the system to 9.0 to obtain a dispersion system containing carbon microspheres. Add 1.6 g of tetraethyl orthosilicate to the obtained dispersion system containing carbon microspheres, and stir evenly to obtain silica gel. Then, transfer the obtained silica gel to a microwave reaction vessel for microwave reaction to age the silica gel. The microwave power is 300 W, the reaction temperature is 80 °C, and the microwave reaction time is 1.5 h. After the obtained product cools, filter it. Wash the obtained solid with ethanol / water until neutral (test the washed solution with pH test paper until neutral), and then dry it. After making the dried solid into powder, place it in a muffle furnace and calcine at 950 °C for 8 h. The obtained white powder is silica extinction powder.

[0042] (3) Add 1.0 g of the silica extinction powder prepared in step (2) and 2.5 g of isopropyltris(dioctylpyrophosphato)titanate to 650 ml of toluene and reflux for 4.5 hours. After the reaction, wash the obtained solid 3 times with 75 ml of toluene. After drying, isopropyltris(dioctylpyrophosphato)titanate modified silica extinction powder can be prepared.

[0043] (4) 5.5 g 345 saturated polyester, 1.2 g amino resin CYMEL303LF, 0.1 g PCA-302 silane coupling agent, 0.1g aluminum hydroxide, 0.5g of isopropyl tri(dioctyl pyrophosphate acyloxy) titanate modified silica matting powder prepared in step (3), 0.7g of modified chitosan prepared in step (1) and aluminum powder coated with metal salt, 0.2g of hydroxyalkylamide and 0.5g of calcium carbonate powder are mixed evenly and sent into a micro extruder for melt extrusion. The temperature of the extruder is set to: 90-95°C in zone I, 95-100°C in zone II, 100-105°C in zone III, and 100-105°C in zone IV; the speed is set to: 950-1000r / min. After extrusion cooling, the obtained solid is crushed and sieved again with 200 mesh to obtain the alkali-resistant silver coating. The obtained coating is recorded as GCXCS-Fe-345SP-CYMEL303LF-1.

[0044] The prepared alkali-resistant silver paint is loaded into an electrostatic spray gun and sprayed evenly on the surface of the metal sheet substrate. After spraying, the metal sheet is quickly placed in an oven for heating and curing. After the fully cured metal sheet is taken out, it is placed in a ventilated and dry place indoors and naturally cooled to room temperature before various performance tests can be performed. Among them, the metal sheet used is a tinplate sheet, and the preparation steps are as follows: the tinplate sheet is cut into a test plate with a size of 50mm×120mm×0.3mm, and the test plate is cleaned according to the provisions of GB9271-1988 for the test plate.

[0045] The impact resistance, adhesion, high temperature resistance, water resistance and alkali corrosion resistance of GCXCS-Fe-345SP-CYMEL303LF-1 coating were measured according to the corresponding standards, as follows: the impact resistance was measured according to the national standard GB / T1732-1993 "Determination of impact resistance of paint film", the adhesion (cross-cut method) was measured according to ISO2409-2007 "cross-cut test for paints and varnishes", the boiling water resistance test was measured according to GB / T1733-1993 "Determination of water resistance of paint films", the alkali resistance test was measured according to GB / T9274-1988 "Determination of liquid medium resistance of paints and varnishes", and the high temperature resistance test was measured by placing the metal substrate after spraying the powder coating in a muffle furnace and baking at different temperatures and observing the changes in appearance. The results are shown in Table 1.

[0046] Embodiment 2:

[0047] The preparation of the alkali-resistant silver coating is based on Example 1, except that the ferric chloride in step (1) is replaced with cobalt chloride. The remaining steps are the same as in Example 1. The obtained alkali-resistant silver coating is recorded as GCXCS-Co-345SP-CYMEL303LF-2.

[0048] The preparation and performance characterization of the GCXCS-Co-345SP-CYMEL303LF-2 coating were the same as those in Example 1; the results are shown in Table 1.

[0049] Example 3:

[0050] The preparation of the alkali-resistant silver paint referred to Example 1, except that ferric chloride in step (1) was replaced with nickel chloride, and the remaining steps were the same as those in Example 1. The obtained alkali-resistant silver paint was denoted as GCXCS-Ni-345SP-CYMEL303LF-3.

[0051] The preparation and performance characterization of the GCXCS-Ni-345SP-CYMEL303LF-3 coating were the same as those in Example 1; the results are shown in Table 1.

[0052] Example 4:

[0053] The preparation of the alkali-resistant silver paint referred to Example 1, except that ferric chloride in step (1) was replaced with chromium trichloride, and the remaining steps were the same as those in Example 1. The obtained alkali-resistant silver paint was denoted as GCXCS-Cr-345SP-CYMEL303LF-4.

[0054] The preparation and performance characterization of the GCXCS-Cr-345SP-CYMEL303LF-4 coating were the same as those in Example 1; the results are shown in Table 1.

[0055] Example 5:

[0056] The preparation of the alkali-resistant silver paint referred to Example 1, except that cetyltrimethylammonium bromide in step (2) was replaced with fatty alcohol polyoxyethylene (20) ether, and the remaining steps were the same as those in Example 1. The obtained alkali-resistant silver paint was denoted as GCXCS-Fe-345SP-CYMEL303LF-5.

[0057] The preparation and performance characterization of the GCXCS-Fe-345SP-CYMEL303LF-5 coating were the same as those in Example 1; the results are shown in Table 1.

[0058] Example 6:

[0059] The preparation of the alkali-resistant silver paint referred to Example 1, except that cetyltrimethylammonium bromide in step (2) was replaced with cetyltrimethylammonium hydroxide, and the remaining steps were the same as those in Example 1. The obtained alkali-resistant silver paint was denoted as GCXCS-Fe-345SP-CYMEL303LF-6.

[0060] The preparation and performance characterization of the GCXCS-Fe-345SP-CYMEL303LF-6 coating were the same as those in Example 1; the results are shown in Table 1.

[0061] Example 7:

[0062] The preparation of the alkali-resistant silver paint refers to Example 1, except that isopropyltri(dioctylpyrophosphate) titanate in step (3) is replaced with methacryloxypropyltrimethoxysilane, and the remaining steps are the same as those in Example 1. The obtained alkali-resistant silver paint is denoted as GCXCS-Fe-345SP-CYMEL303LF-7.

[0063] The preparation and performance characterization of the GCXCS-Fe-345SP-CYMEL303LF-7 coating are the same as those in Example 1; the results are shown in Table 1.

[0064] Example 8:

[0065] The preparation of the alkali-resistant silver paint refers to Example 1, except that 345 saturated polyester in step (4) is replaced with 301B saturated polyester, and the remaining steps are the same as those in Example 1. The obtained alkali-resistant silver paint is denoted as GCXCS-Fe-301BSP-CYMEL303LF-8.

[0066] The preparation and performance characterization of the GCXCS-Fe-301B SP-CYMEL303LF-8 coating are the same as those in Example 1; the results are shown in Table 1.

[0067] Example 9:

[0068] The preparation of the alkali-resistant silver paint refers to Example 1, except that 345 saturated polyester in step (4) is replaced with 385 saturated polyester, and the remaining steps are the same as those in Example 1. The obtained alkali-resistant silver paint is denoted as GCXCS-Fe-385SP-CYMEL303LF-9.

[0069] The preparation and performance characterization of the GCXCS-Fe-385SP-CYMEL303LF-9 coating are the same as those in Example 1; the results are shown in Table 1..

[0070] Example 10:

[0071] The preparation of the alkali-resistant silver paint refers to Example 1, except that CYMEL303LF in step (4) is replaced with CYMEL308, and the remaining steps are the same as those in Example 1. The obtained alkali-resistant silver paint is denoted as GCXCS-Fe-345SP-CYMEL308-10.

[0072] The preparation and performance characterization of the GCXCS-Fe-345SP-CYMEL308-10 coating are the same as those in Example 1; the results are shown in Table 1.

[0073] Example 11:

[0074] The preparation of the alkali-resistant silver paint refers to Reference Example 1, except that CYMEL 327 is used instead of CYMEL303LF in step (4), and the remaining steps are the same as in Example 1. The obtained alkali-resistant silver paint is denoted as GCXCS-Fe-345SP-CYMEL327-11.

[0075] The preparation and performance characterization of the GCXCS-Fe-345SP-CYMEL 327-11 coating are the same as in Example 1; the results are shown in Table 1.

[0076] Example 12:

[0077] The preparation of the alkali-resistant silver paint refers to Reference Example 1, except that the amount of 345 saturated polyester in step (4) is changed from 5.5 g to 5.0 g, CYMEL303LF is replaced by CYMEL308, and the amount of CYMEL308 is 1.7 g; the remaining steps are the same as in Example 1. The obtained alkali-resistant silver paint is denoted as Fe-345SP-CYMEL308-12. The preparation and performance characterization of the Fe-345SP-CYMEL308-12 coating are the same as in Example 1; the results are shown in Table 1.

[0078] Table 1 Performance Characterization Table of Alkali-Resistant Silver Paint

[0079] Impact resistance Adhesion Boiling water resistance High temperature resistance Alkali resistance Example 1 No cracks Grade 1 10h 90℃ 168h Example 2 No cracks Grade 1 10h 90℃ 168h Example 3 No cracks Grade 2 8h 80℃ 144h Example 4 No cracks Grade 1 12h 100℃ 192h Example 5 No cracks Grade 2 8h 80℃ 144h Example 6 No cracks Grade 1 10h 90℃ 168h Example 7 No cracks Grade 2 8h 90℃ 144h Example 8 No cracks Grade 2 8h 80℃ 144h Example 9 No cracks Grade 2 8h 90℃ 144h Example 10 No cracks Grade 1 10h 100℃ 168h Example 11 No cracks Grade 1 12h 110℃ 192h Example 12 No cracks Grade 0 14h 120℃ 216h Comparative example 1 No cracks Grade 2 6h 70℃ 96h Comparative example 2 Cracks Grade 3 4h 60℃ 48h

[0080] Note: The anti-impact strength selected for the impact resistance test is 50 kg·cm, and the time for boiling water resistance, high temperature resistance, and alkali resistance refers to the time when the coating has no blistering, no peeling, and no color change under the test conditions.

[0081] Comparative Example 1:

[0082] The preparation of the alkali-resistant silver paint refers to Reference Example 1, except that chitosan is used instead of modified chitosan in step (1), and the remaining steps are the same as in Example 1. The obtained alkali-resistant silver paint is denoted as CS-Fe-345SP-CYMEL303LF-13.

[0083] The preparation and performance characterization of the CS-Fe-345SP-CYMEL303LF-13 coating are the same as in Example 1; the results are shown in Table 1.

[0084] Comparative Example 2:

[0085] The preparation steps of the alkali-resistant silver paint are as follows:

[0086] Mix 5.5 g of 345 saturated polyester, 1.2 g of amino resin CYMEL303LF, 0.1 g of PCA-302 silane coupling agent, 0.1 g of aluminum hydroxide, 0.5 g of silica powder (commercially available commercial product), 0.7 g of aluminum powder (unmodified), 0.2 g of hydroxyalkylamide, and 0.5 g of calcium carbonate powder evenly, and then send them into a micro extruder for melt extrusion. Set the temperature of the extruder as follows: Zone I 90 - 95 °C, Zone II 95 - 100 °C, Zone III 100 - 105 °C, Zone IV 100 - 105 °C; set the rotation speed as: 950 - 1000 r / min. After extrusion and cooling, crush the obtained solid again and sieve it through 200 meshes to obtain the alkali-resistant silver paint, and record the obtained paint as 345SP-CYMEL303LF-14.

[0087] The preparation and performance characterization of the 345SP-CYMEL303LF-14 coating are the same as those in Example 1; the results are shown in Table 1.

Claims

1. A method for preparing an alkali-resistant silver coating, characterized in that: The steps include: (1) adding the pretreated aluminum powder into a solvent, and then adding chitosan and an inorganic metal salt to react to obtain aluminum powder coated with chitosan and metal salt; (2) adding the template and carbon microspheres to an alkaline solution and dispersing them uniformly, and then adding an organic silicate to the resulting mixture for reaction to obtain a silica matting powder; (3) adding the silica matting powder and the modifier prepared in step (2) into toluene for reflux reaction to prepare a surface-modified silica matting powder; (4) The chitosan prepared in step (1) is mixed with the aluminum powder coated with a metal salt, the surface-modified silica matting powder prepared in step (3), a promoter, a flame retardant, an auxiliary agent and a filler, and then fed into an extruder for melt extrusion. After extrusion and cooling, the mixture is crushed and sieved to obtain the alkali-resistant silver coating.

2. The method for preparing the alkali-resistant silver coating according to claim 1, characterized in that: The particle size of the aluminum powder described in step (1) is 1 to 10 microns.

3. The method for preparing the alkali-resistant silver paint according to claim 1, characterized in that: The chitosan described in step (1) is modified chitosan.

4. The method for preparing the alkali-resistant silver paint according to claim 1, characterized in that: The inorganic metal salt described in step (1) is one of iron salt, chromium salt, nickel salt or cobalt salt.

5. The method for preparing the alkali-resistant silver paint according to claim 1, characterized in that: The template agent described in step (2) is one of hexadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, fatty alcohol polyoxyethylene (20) ether or hexadecyltrimethylammonium hydroxide.

6. The method for preparing the alkali-resistant silver paint according to claim 1, characterized in that: The organic silicate described in step (2) is one of ethyl orthosilicate or isopropyl orthosilicate.

7. The method for preparing the alkali-resistant silver paint according to claim 1, characterized in that: The modifier described in step (3) is one of methacryloxypropyltrimethoxysilane, isopropyl tri(dioctylpyrophosphate) titanate, stearic acid, lauric acid or oleic acid.

8. The method for preparing the alkali-resistant silver paint according to claim 1, characterized in that: The saturated polyester resin described in step (4) is one of 345 saturated polyester, 301B saturated polyester or 385 saturated polyester; the amino resin is one of CYMEL303LF, CYMEL308 or CYMEL327 amino resin; the promoter is one or more of PCA-302 silane coupling agent, BYK-3941P adhesion promoter or L216 promoter; the flame retardant is a mixture of one or both of aluminum hydroxide and magnesium hydroxide; the auxiliary agent is hydroxyalkylamide; and the filler is calcium carbonate powder.

9. The silver paint prepared by the method for preparing an alkali-resistant silver paint according to claim 1, characterized in that: The composition comprises the following components in parts by weight: 50-55 parts of saturated polyester resin; 10-18 parts of amino resin; Accelerator 0.5-1 part; 1-2 parts of flame retardant; 3-5 parts of surface modified silica matting powder; 5-8 parts of chitosan and aluminum powder coated with metal salt; 2-3 parts of additives; 3 to 5 parts of filler.

10. Use of a coating obtained by the preparation method of the alkali-resistant silver coating as claimed in any one of claims 1 to 8 or the alkali-resistant silver coating as claimed in claim 9 in corrosion protection of metal materials.