Nano-silver-based metal protective coating and preparation method thereof
By sandblasting and pickling the metal substrate and nanosilver particles modification treatment, a stable nanosilver coating is formed, which solves the problems of uneven dispersion and insufficient adhesion of the nanosilver coating on the metal substrate, and achieves better anti-corrosion and antibacterial effects.
Patent Information
- Application Number
- CN202510446836.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-10
- Publication Date
- 2025-07-11
AI Technical Summary
The existing nanosilver coatings are unevenly dispersed on metal substrates and insufficient adhesion, resulting in unstable anticorrosion and antibacterial properties, and cannot effectively inhibit the growth of bacteria and mold on the metal surface.
The metal substrate is treated with sandblasting and pickling to form a roughness pretreated substrate, and then sprayed with an aqueous epoxy resin base layer containing carboxysilane, and then sprayed with nanosilver-based paste. The nanosilver particles are modified by mercaptosilane and aminoacrylate grafting treatment to form a stable monolayer, enhancing the binding force with the resin and the substrate, and loading the nanosilver particles with a silica support to improve dispersion and adhesion.
It improves the dispersion uniformity and adhesion of nano-silver coating on metal substrates, enhances anti-corrosion and antibacterial properties, inhibits the growth of bacteria and mold on metal surfaces, and improves the stability and antibacterial durability of the coating.
Smart Images
Figure BDA0005352850470000181
Abstract
Description
Technical Field
[0001] This application relates to the field of metal coatings, and more specifically, to a nano silver-based metal protective coating and a preparation method thereof. Background Art
[0002] With the continuous advancement of China's marine strategy, the surfaces of offshore equipment and marine facilities are facing environments such as high temperature, high heat, and high salinity. Such environments are extremely likely to cause severe corrosion on the surface of metal materials. At the same time, the special environment of high temperature and high humidity is also extremely likely to cause bacteria and molds to grow on the surface of equipment, and mechanical equipment in enclosed spaces is an ideal breeding ground for bacteria and molds. The rapid reproduction of bacteria and molds will not only accelerate the corrosion and failure of materials, but also seriously affect the service life of metal materials. Therefore, the research on metal material protective coating materials is of great significance.
[0003] Although there are many functional coatings currently used to solve metal protection problems, these coatings have single functions and less research on antibacterial coatings. The antibacterial property of nano silver is powerful and can effectively deal with common pathogens such as Escherichia coli, Staphylococcus aureus, Candida albicans, and stubborn fungi. Applying it to metal protective coatings can effectively inhibit the growth of bacteria and molds on the metal surface, reduce the risk of material corrosion and failure caused by the reproduction of bacteria and molds, and is of great significance for ensuring the normal operation of equipment and the life and health of staff.
[0004] However, the uneven dispersion of nano materials in the coating substrate leads to unstable coating performance, and the adhesion of nano coatings on metal substrates is of great significance for the anti-corrosion and antibacterial properties of the final coatings. It is necessary to study the above two problems to improve the protective performance. Summary of the Invention
[0005] In order to improve the uniform dispersion of nano silver in the coating substrate and at the same time improve the adhesion between the nano coating and the metal substrate, this application provides a nano silver-based metal protective coating and a preparation method thereof.
[0006] In the first aspect, this application provides a nano silver-based metal protective coating and a preparation method thereof, adopting the following technical solutions:
[0007] A preparation method of a nano silver-based metal protective coating includes the following steps:
[0008] S1. First, clean and degrease the metal substrate and then perform sandblasting and pickling treatment to obtain a pretreated substrate;
[0009] S2. Coat a transition layer solution on the surface of the pretreated substrate and form a bottom layer after curing. The transition layer solution is prepared from carboxyl silane, water-based epoxy resin, and water;
[0010] S3. Spray a nano-silver-based slurry on the bottom layer, and after curing, form a surface layer to form a nano-silver-based metal protective coating composed of a bottom layer and a surface layer on the metal substrate;
[0011] Among them, the nano-silver-based slurry includes the following raw materials in parts by weight:
[0012] 20 - 30 parts of hydroxyl-containing acrylic resin, 50 - 70 parts of waterborne epoxy resin, 15 - 30 parts of vinyl resin, 5 - 10 parts of titanate coupling agent, 3 - 8 parts of dispersant, 3 - 5 parts of crosslinking agent, 5 - 10 parts of filler, 10 - 25 parts of solvent, and 10 - 20 parts of modified nano-silver particles;
[0013] Among them, the modified nano-silver particles are prepared by first treating nano-silver particles with mercapto-silane and then grafting with amino acrylate.
[0014] By adopting the above technical solution, in this application, the metal substrate is first cleaned and then sandblasted to form a pretreated substrate with a certain roughness. Then, it is immersed in a waterborne epoxy resin containing carboxyl silane to form a bottom layer, and a transition layer containing active groups is formed on the metal surface. Then, a nano-silver-based slurry is sprayed to form a surface layer. The addition of nano-silver in the surface layer has an antibacterial effect, which can effectively inhibit the growth of bacteria and molds on the metal surface, resulting in material corrosion failure. The hydroxyl-containing acrylic resin, waterborne epoxy resin, and vinyl resin serve as the resin matrix to provide the basis for the protective coating. The addition of the titanate coupling agent improves the interfacial bonding between the filler and nano-silver and the organic resin, improving the dispersion uniformity. The addition of the dispersant prevents the aggregation of nano-silver particles and ensures the stability of the slurry. The addition of the filler improves the mechanical properties and wear resistance of the coating.
[0015] In this application, the addition of nano - silver is directly added in the form of its modified particles. The modified nano - silver is first treated with mercapto - silane. Covalent bonds are formed between the mercapto group and silver, so that the surface of the nano - silver particles is tightly wrapped by mercapto molecules, forming a stable monolayer, effectively blocking the direct contact between nano - silver particles, reducing agglomeration. Moreover, the organic chain segments in mercapto - silane form steric hindrance, further reducing agglomeration and enhancing the dispersion stability. Then, after grafting treatment with amino - acrylate, amino and double - bond groups are introduced on the surface of the nano - silver particles. The introduction of amino functional groups can react with carboxyl groups on the bottom layer or hydroxyl groups on the metal substrate to form chemical bonding, thus significantly improving the adhesion between the coating and the metal substrate. The introduction of double - bond groups can cross - link with the resin to form a three - dimensional network structure, further fixing the nano - silver particles, preventing their migration and agglomeration, and forming a network structure penetrating the coating, enhancing the interfacial bonding force between nano - silver and resin. Finally, the prepared coating has better protective performance. The inner - layer hydrophobic mercapto - silane reduces the surface polarity of nano - silver, making its compatibility with organic resin better. The outer - layer hydrophilic amino groups enhance the affinity with the polar metal substrate, improving the polar matching degree of the nano - silver - resin - metal substrate interface, realizing the simultaneous improvement of dispersibility and adhesion, and having better bonding strength with the substrate.
[0016] Optionally, in step S2, the carboxyl - silane in the transition - layer solution is selected from γ - carboxypropyltrimethoxysilane or γ - carboxypropyltriethoxysilane;
[0017] In step S3, the mercapto - silane in the nano - silver - based slurry is selected from 3 - mercaptopropyltrimethoxysilane, and the amino - acrylate is selected from a mixture of amino(meth)acrylate and γ - aminopropyltriethoxysilane.
[0018] Optionally, the modified nano - silver particles are prepared by the following method:
[0019] 1). Dissolve mercapto - silane in an ethanol - aqueous solution, stir to generate a hydrolyzed silane solution, then add nano - silver particles, ultrasonically disperse at 50 - 60 °C for 20 - 30 min, and then centrifuge and wash with alcohol to obtain an inner - layer modified nano - silver intermediate;
[0020] 2). Disperse the prepared inner - layer modified nano - silver intermediate in a mixed solution of propylene glycol monomethyl ether acetate and ethanol - aqueous solution, then add amino - acrylate and genipin, heat up to 60 - 70 °C, stir and react for 1 - 2 h, and then wash with alcohol and centrifuge and dry to obtain modified nano - silver particles.
[0021] By adopting the above technical solution, first, mercapto-silane is dispersed in an ethanol aqueous solution to form silanol, and after adding nano silver particles, ultrasonic dispersion is carried out. Covalent bond assembly between the mercapto group and silver is achieved to realize inner layer adsorption modification. Then, it is grafted with amino acrylate, and the amino acrylate is a mixture of amino (meth) acrylate and γ-aminopropyltriethoxysilane. The amino (meth) acrylate contains double bonds and amino functional groups, while γ-aminopropyltriethoxysilane contains amino functional groups and ethoxy groups. The silanol groups formed after hydrolysis of the ethoxy groups condense with the inner layer mercapto-silane groups. On the other hand, under the action of genipin, the amino groups are crosslinked. In this way, the amino acrylate is grafted onto the outer layer of the nano silver. At the same time, the amino groups are exposed outward, and the double bonds are also distributed on the outside, providing active sites for crosslinking with the resin and bonding with the substrate, realizing crosslinking with the resin and forming chemical bonding with the substrate, thereby improving the adhesion force.
[0022] Optionally, when preparing the modified nano silver particles, in step 1), the mass ratio of the mercapto-silane to the ethanol aqueous solution added is 1:(8 - 10), and the ethanol aqueous solution is a 40 - 50wt% ethanol solution. The mass ratio of the nano silver particles to the mercapto-silane added is 1:(0.2 - 0.3);
[0023] In step 2), the mass ratio of the propylene glycol methyl ether acetate to the ethanol aqueous solution added is 1:(0.6 - 0.8), and the ethanol aqueous solution is a 40 - 50wt% ethanol solution;
[0024] The mass ratio of the inner layer modified nano silver intermediate to the mixed solution added is 1:(6 - 8). The amino acrylate is selected as a mixture of amino (meth) acrylate and γ-aminopropyltriethoxysilane with a mass ratio of 1:(0.5 - 0.8), and the addition amount of the amino acrylate is 5 - 8wt% of the inner layer modified nano silver intermediate, and the addition amount of genipin is 0.3 - 0.8wt% of the inner layer modified nano silver intermediate.
[0025] Optionally, the modified nano silver particles are also added after being post-treated to form modified nano silver-silica composite particles. The specific post-treatment operation is as follows: The modified nano silver particles are loaded on a silica carrier and then modified with γ-methacryloxypropyltrimethoxysilane and glycidyl ether oxypropyltrimethoxysilane.
[0026] By adopting the above technical solution, the modified nano-silver particles are loaded on the surface of silica. By utilizing the high specific surface area and stability of silica, the modified nano-silver particles are further effectively dispersed to reduce agglomeration. Moreover, after subsequent modification treatment with γ-methacryloxypropyltrimethoxysilane and glycidoxypropyltrimethoxysilane, a double bond is introduced in γ-methacryloxypropyltrimethoxysilane, which can participate in resin cross-linking, and the silanol group can condense with the hydroxyl groups of the substrate. The epoxy group in glycidoxypropyltrimethoxysilane can act on the hydroxyl groups of the waterborne epoxy resin and form a covalent bond with the metal substrate at the same time. In this way, on the one hand, the agglomeration is reduced by loading with silica, and the silica carrier also acts as a filler at the same time, improving the coating density and having better protection performance. Moreover, the slow release of nano-silver is realized after the nano-silver is loaded on silica, so as to improve the persistence of antibacterial effect. Finally, the prepared coating has better comprehensive antibacterial and protection performance.
[0027] Optionally, the specific operation of the post-treatment of the modified nano-silver particles is as follows:
[0028] 3), Disperse silica in an ethanol solution, add 3-aminopropyltrimethoxysilane, and stir for 30-40 min to obtain a pretreated silica solution;
[0029] 4), Disperse the modified nano-silver particles in ethanol, then add the pretreated silica solution, after ultrasonic dispersion for 20-30 min, add γ-methacryloxypropyltrimethoxysilane and glycidoxypropyltrimethoxysilane, stir, centrifuge, wash, and dry to obtain silver-silica composite particles.
[0030] By adopting the above technical solution, first, silica is dispersed and then treated with 3-aminopropyltrimethoxysilane to enhance the surface active sites, and then it is ultrasonically dispersed. The amino group on the modified nano-silver particles can form a chemical bond with the surface hydroxyl groups of silica to achieve physical adsorption. Then, with the cooperation of γ-methacryloxypropyltrimethoxysilane and glycidoxypropyltrimethoxysilane treatment, it can act on the silica surface and form a covalent bond with the amino group or epoxy group on the modified nano-silver at the same time, realizing the firmness and stability of loading. In this way, the loading of nano-silver on silica can be realized, reducing agglomeration while achieving slow release. Moreover, the double bonds on the nano-silver and the double bonds introduced by the post-treatment cooperate with the waterborne epoxy resin and vinyl resin to form a cross-linked structure, and the remaining amino groups and epoxy groups on the nano-silver can act on the hydroxyl groups of the waterborne epoxy resin to form an interpenetrating network cross-linked structure. Finally, the prepared coating has good adhesion while having better antibacterial effect and persistence.
[0031] Optionally, during the post-treatment of the modified nano silver particles, in step 3), the addition amount of the ethanol solution is 4-6 times the mass of the silica addition amount, the mass concentration of the ethanol solution is 40-50%, and the addition amount of 3-aminopropyltrimethoxysilane is 3-5 wt% of the silica;
[0032] In step 4), the mass ratio of the modified nano silver particles to the silica addition amount is 1:(1.8-2.2), the addition amount of γ-methacryloxypropyltrimethoxysilane is 3-5 wt% of the modified nano silver particles, and the addition amount of glycidyl ether oxypropyltrimethoxysilane is 3-8 wt% of the modified nano silver particles.
[0033] Optionally, the transition layer solution is prepared by mixing carboxyl silane, waterborne epoxy resin and water in a mass ratio of 1:(4-6):(1-1.5).
[0034] Optionally, the dispersant is a mixture of propylene glycol methyl ether and polyvinylpyrrolidone with a mass ratio of 1:(2-3);
[0035] The filler is selected from one or more of talcum powder, silica, and calcium carbonate;
[0036] The crosslinking agent is selected from HDI trimers;
[0037] The solvent is a mixed solvent prepared by mixing methyl ethyl ketone and propylene glycol methyl ether acetate in a volume ratio of 1:(1-2).
[0038] By adopting the above technical solution, the isocyanate crosslinking agent can crosslink with chemical groups containing amino or hydroxyl groups to achieve crosslinking and curing of the coating.
[0039] Optionally, the curing parameters in step S2 are: heat preservation at 120-130 °C for 10-20 min to form the bottom layer;
[0040] The curing parameters in step S3 are: first heat preservation at 80-90 °C for 20-30 min, then raise the temperature to 120-130 °C for heat preservation for 15-25 min, and then raise the temperature to 150-160 °C for heat preservation for 10-20 min to cure and form the surface layer.
[0041] By adopting the above technical solution, the bottom layer forms an anchoring point of metal-silane active site-resin through curing, and the surface layer promotes the chemical bonding between the modified nano silver, the resin and the metal substrate through gradient temperature curing, to obtain a coating with excellent dense protection performance, and at the same time, the coating has good adhesion to the metal substrate.
[0042] In the second aspect, the present application provides a nano silver-based metal protective coating, adopting the following technical solution:
[0043] A nano silver-based metal protective coating prepared by the described preparation method.
[0044] By adopting the above technical solution, nano silver is added to the nano silver-based metal protective coating prepared by the method provided in this application. The obtained coating has the anti-corrosion protection effect and also has the antibacterial effect, effectively inhibiting the corrosion failure of the material caused by the growth of bacteria and molds on the metal surface. Moreover, the adhesion of the coating obtained in this application to the metal substrate is better.
[0045] In summary, this application has the following beneficial effects:
[0046] 1. In this application, the metal substrate is first cleaned and then sandblasted to form a pre-treated substrate with a certain roughness. Then, it is formed into a bottom layer in the water-based epoxy resin containing carboxyl silane to form a transition layer containing active groups on the metal surface. Then, the nano silver-based slurry is sprayed to form a surface layer. The addition of nano silver in the surface layer plays an antibacterial effect, thereby effectively inhibiting the corrosion failure of the material caused by the growth of bacteria and molds on the metal surface. The hydroxyl-containing acrylic resin, water-based epoxy resin, and vinyl resin are used as the resin matrix to provide the basis for the protective coating. The addition of titanate coupling agent improves the interfacial bonding between the filler and nano silver and the organic resin, improves the dispersion uniformity. The addition of the dispersant prevents the aggregation of nano silver particles and ensures the stability of the slurry. The addition of the filler improves the mechanical properties and wear resistance of the coating;
[0047] 2. In this application, the modified nano silver is first treated with mercapto silane. Covalent bonds are formed between the mercapto group and silver, so that the surface of the nano silver particles is tightly wrapped by mercapto molecules, forming a stable monolayer, effectively blocking the direct contact between nano silver particles, reducing aggregation, and the organic chain segment in mercapto silane forms a steric hindrance, further reducing aggregation and improving the dispersion stability; Then, it is grafted with amino acrylate to introduce amino and double bond groups on the surface of the nano silver particles. The introduction of the amino functional group can react with the carboxyl group on the bottom layer or the hydroxyl group on the metal substrate to form chemical bonding, thus significantly improving the adhesion of the coating to the metal substrate. The introduction of the double bond group can crosslink with the resin to form a three-dimensional network structure, further fixing the nano silver particles, preventing their migration and aggregation, and forming a network structure penetrating the coating, enhancing the interfacial bonding force between nano silver and the resin. Finally, the obtained coating has better protective performance. The inner hydrophobic mercapto silane reduces the surface polarity of nano silver, making it more compatible with the organic resin. The outer hydrophilic amino group enhances the affinity with the polar metal substrate, improving the interfacial polarity matching degree of nano silver-resin-metal substrate, and realizing the synchronous improvement of dispersion and adhesion, and having better bonding strength with the substrate. Detailed implementation mode
[0048] The present application will be further described in detail below in conjunction with embodiments. It should be specifically noted that: for those conditions not specified in the following embodiments, they shall be carried out according to conventional conditions or the conditions recommended by the manufacturer. Except as otherwise specified, the raw materials used in the following embodiments can all be obtained from ordinary commercial sources.
[0049] In the following embodiments, the waterborne epoxy resin is the waterborne epoxy resin with the model ST-00 produced by Langfang Xinhao Chang Anticorrosive Material Co., Ltd.
[0050] The hydroxyl-containing acrylic resin is the waterborne hydroxyl-containing acrylic resin with the brand 9080 produced by Jining Tangyi Chemical Co., Ltd., and the hydroxyl content is 4%.
[0051] The vinyl resin is the Shangwei 901 vinyl resin produced by Jiangyin Wanqian Chemicals Co., Ltd.
[0052] The following preparation example is for the preparation of modified nano silver particles
[0053] Preparation Example 1
[0054] A method for preparing modified nano silver particles, comprising the following steps:
[0055] 1), Dissolve 3-mercaptopropyltrimethoxysilane in an ethanol aqueous solution with a mass concentration of 45%, and the added mass ratio of 3-mercaptopropyltrimethoxysilane to the ethanol aqueous solution is 1:9. After stirring for 30 min, a hydrolyzed silane solution is formed, and then nano silver particles with a particle size of 20 - 50 nm are added. The added mass ratio of the nano silver particles to 3-mercaptopropyltrimethoxysilane is 1:0.2. After ultrasonic dispersion at 55 °C for 25 min, centrifugation and alcohol washing are carried out, and the ultrasonic power is 100 W to obtain an inner layer modified nano silver intermediate;
[0056] 2), Mix propylene glycol methyl ether acetate and an ethanol aqueous solution with a concentration of 45 wt% according to an added mass ratio of 1:0.7 to obtain a mixed solution, and then disperse the inner layer modified nano silver intermediate prepared in step 1) in the mixed solution. The added mass ratio of the inner layer modified nano silver intermediate to the mixed solution is 1:7. Then add aminoacrylate and genipin, heat up to 65 °C, stir and react for 1.5 h, and then carry out alcohol washing, centrifugation and drying to obtain modified nano silver particles;
[0057] Among them, the addition amount of aminoacrylate is 6 wt% of the inner layer modified nano silver intermediate, and the aminoacrylate is a mixture of amino (meth) acrylate and γ-aminopropyltriethoxysilane with a mass ratio of 1:0.6. The addition amount of genipin is 0.5 wt% of the inner layer modified nano silver intermediate.
[0058] Preparation Example 2
[0059] A method for preparing modified nano silver particles, comprising the following steps:
[0060] 1), Dissolve 3-mercaptopropyltrimethoxysilane in an ethanol aqueous solution with a mass concentration of 40%, and the added mass ratio of 3-mercaptopropyltrimethoxysilane to the ethanol aqueous solution is 1:8. After stirring for 30 min, a hydrolyzed silane solution is formed. Then, add silver nanoparticles with a particle size of 20 - 50 nm. The added mass ratio of silver nanoparticles to 3-mercaptopropyltrimethoxysilane is 1:0.2. After ultrasonic dispersion at 50 °C for 30 min, centrifuge and wash with alcohol. The ultrasonic power is 100 W to obtain an inner layer modified silver nanoparticle intermediate;
[0061] 2), Mix propylene glycol methyl ether acetate and an ethanol aqueous solution with a concentration of 40 wt% according to an added mass ratio of 1:0.6 to obtain a mixed solution. Then, disperse the inner layer modified silver nanoparticle intermediate prepared in step 1) in the mixed solution. The added mass ratio of the inner layer modified silver nanoparticle intermediate to the mixed solution is 1:6. Then, add aminoacrylate and genipin, heat up to 60 °C, stir and react for 2 h, and then wash with alcohol, centrifuge and dry to obtain modified silver nanoparticles;
[0062] Among them, the addition amount of aminoacrylate is 5 wt% of the inner layer modified silver nanoparticle intermediate, and the aminoacrylate is a mixture of amino(meth)acrylate and γ-aminopropyltriethoxysilane with a mass ratio of 1:0.5. The addition amount of genipin is 0.3 wt% of the inner layer modified silver nanoparticle intermediate.
[0063] Preparation Example 3
[0064] A preparation method of modified silver nanoparticles, comprising the following steps:
[0065] 1), Dissolve 3-mercaptopropyltrimethoxysilane in an ethanol aqueous solution with a mass concentration of 50%, and the added mass ratio of 3-mercaptopropyltrimethoxysilane to the ethanol aqueous solution is 1:10. After stirring for 30 min, a hydrolyzed silane solution is formed. Then, add silver nanoparticles with a particle size of 20 - 50 nm. The added mass ratio of silver nanoparticles to 3-mercaptopropyltrimethoxysilane is 1:0.3. After ultrasonic dispersion at 60 °C for 20 min, centrifuge and wash with alcohol. The ultrasonic power is 100 W to obtain an inner layer modified silver nanoparticle intermediate;
[0066] 2), Mix propylene glycol methyl ether acetate and an ethanol aqueous solution with a concentration of 50 wt% according to an added mass ratio of 1:0.8 to obtain a mixed solution. Then, disperse the inner layer modified silver nanoparticle intermediate prepared in step 1) in the mixed solution. The added mass ratio of the inner layer modified silver nanoparticle intermediate to the mixed solution is 1:8. Then, add aminoacrylate and genipin, heat up to 70 °C, stir and react for 1 h, and then wash with alcohol, centrifuge and dry to obtain modified silver nanoparticles;
[0067] Among them, the addition amount of aminoacrylate is 8 wt% of the inner layer modified nano-silver intermediate, and the aminoacrylate is a mixture of amino(meth)acrylate and γ-aminopropyltriethoxysilane with a mass ratio of 1:0.8. The addition amount of genipin is 0.8 wt% of the inner layer modified nano-silver intermediate.
[0068] Preparation Example 4
[0069] A preparation method of modified nano-silver-silica composite particles includes the following steps:
[0070] The modified nano-silver particles obtained in Preparation Example 1 are post-treated to form modified nano-silver-silica composite particles, which specifically include the following steps:
[0071] 3), Dispersing silica with a particle size of 300-500 nm in an ethanol solution with a concentration of 45 wt%, the addition amount of the ethanol solution is 5 times the mass of the silica addition amount, adding 3-aminopropyltrimethoxysilane, and the addition amount of 3-aminopropyltrimethoxysilane is 4 wt% of the silica, stirring for 35 min to obtain a pretreated silica solution;
[0072] 4), Dispersing the modified nano-silver particles obtained in step 2) of Preparation Example 1 in 2.5 times the mass of ethanol, and then adding the pretreated silica solution obtained in step 3). The mass ratio of the modified nano-silver particles to the silica addition is 1:2. After ultrasonic dispersion for 25 min, γ-methacryloxypropyltrimethoxysilane and glycidyl ether oxypropyltrimethoxysilane are added, and after stirring, centrifuged and washed, and dried to obtain nano-silver-silica composite particles;
[0073] Among them, the addition amount of γ-methacryloxypropyltrimethoxysilane is 4 wt% of the modified nano-silver particles, and the addition amount of glycidyl ether oxypropyltrimethoxysilane is 5 wt% of the modified nano-silver particles.
[0074] Preparation Example 5
[0075] A preparation method of modified nano-silver-silica composite particles includes the following steps:
[0076] The modified nano-silver particles obtained in Preparation Example 2 are post-treated to form modified nano-silver-silica composite particles, which specifically include the following steps:
[0077] 3), Dispersing silica with a particle size of 300-500 nm in an ethanol solution with a concentration of 40 wt%, the addition amount of the ethanol solution is 4 times the mass of the silica addition amount, adding 3-aminopropyltrimethoxysilane, and the addition amount of 3-aminopropyltrimethoxysilane is 3 wt% of the silica, stirring for 30 min to obtain a pretreated silica solution;
[0078] 4), Disperse the modified nano silver particles obtained in step 2) of Preparation Example 2 in ethanol with a mass multiple of 2, then add them to the pretreated silica solution obtained in step 3). The mass ratio of the modified nano silver particles to the added silica is 1:1.8. After ultrasonic dispersion for 20 min, add γ-methacryloxypropyltrimethoxysilane and glycidyl ether oxypropyltrimethoxysilane, stir, then centrifuge and wash, and dry to obtain rice silver-silica composite particles;
[0079] Among them, the addition amount of γ-methacryloxypropyltrimethoxysilane is 3 wt% of the modified nano silver particles, and the addition amount of glycidyl ether oxypropyltrimethoxysilane is 3 wt% of the modified nano silver particles.
[0080] Preparation Example 6
[0081] A preparation method of modified nano silver-silica composite particles, comprising the following steps:
[0082] Subject the modified nano silver particles obtained in Preparation Example 3 to post-treatment to form modified nano silver-silica composite particles, specifically including the following steps:
[0083] 3), Disperse silica with a particle size of 300 - 500 nm in an ethanol solution with a concentration of 50 wt%. The addition amount of the ethanol solution is 6 mass multiples of the addition amount of silica. Add 3-aminopropyltrimethoxysilane, and the addition amount of 3-aminopropyltrimethoxysilane is 5 wt% of the silica. Stir for 40 min to obtain a pretreated silica solution;
[0084] 4), Disperse the modified nano silver particles obtained in step 2) of Preparation Example 3 in ethanol with a mass multiple of 2 - 3, then add them to the pretreated silica solution obtained in step 3). The mass ratio of the modified nano silver particles to the added silica is 1:2.2. After ultrasonic dispersion for 30 min, add γ-methacryloxypropyltrimethoxysilane and glycidyl ether oxypropyltrimethoxysilane, stir, then centrifuge and wash, and dry to obtain rice silver-silica composite particles;
[0085] Among them, the addition amount of γ-methacryloxypropyltrimethoxysilane is 5 wt% of the modified nano silver particles, and the addition amount of glycidyl ether oxypropyltrimethoxysilane is 8 wt% of the modified nano silver particles.
[0086] Preparation Example 7
[0087] A preparation method of modified nano silver-silica composite particles is carried out according to the method in Preparation Example 4, the difference being that γ-methacryloxypropyltrimethoxysilane is not added in step 4).
[0088] Preparation Example 8
[0089] A preparation method of modified nano silver-silica composite particles is carried out according to the method in Preparation Example 4, except that in step 4), glycidyl ether oxypropyltrimethoxysilane is not added.
[0090] Comparative Preparation Example 1
[0091] A preparation method of modified nano silver particles is carried out according to the method in Preparation Example 1, except that step 1) is not carried out, and the inner layer modified nano silver intermediate in step 2) is directly replaced with nano silver particles in equal amount.
[0092] Comparative Preparation Example 2
[0093] A preparation method of modified nano silver particles is carried out according to the method in Preparation Example 1, except that the amino acrylate in step 2) is replaced with γ-aminopropyltriethoxysilane in equal amount.
[0094] Example 1
[0095] A preparation method of a nano silver-based metal protective coating includes the following steps:
[0096] S1. First, clean and degrease the metal substrate, then spray alumina sand grains with a mesh size of 80 - 120 to form a rough surface with a roughness of 2 μm, then soak it in a 20 wt% hydrochloric acid solution for 10 min for pickling, then immerse it in a 5 wt% sodium carbonate solution for 30 s for neutralization, and then wash it with water and dry it to obtain a pretreated substrate;
[0097] S2. Mix carboxyl silane, waterborne epoxy resin and water in a mass ratio of 1:5:1.2 to obtain a transition layer solution, and the carboxyl silane is selected as γ-carboxypropyltrimethoxysilane;
[0098] Then spray the transition layer solution on the surface of the pretreated substrate in step S1, and keep it warm at 125 °C for 15 min to form a bottom layer with a thickness of 0.1 mm;
[0099] S3. Mix 25 kg of hydroxy acrylic resin, 60 kg of waterborne epoxy resin, 20 kg of vinyl resin and 15 kg of solvent to obtain a preliminary mixture; mix 8 kg of titanate coupling agent, 5 kg of dispersant, 4 kg of crosslinking agent, 8 kg of filler and 15 kg of modified nano silver particles prepared in Preparation Example 1, and then add them to the preliminary mixture and stir under vacuum conditions to obtain a nano silver-based slurry;
[0100] Among them, the solvent is a mixed solvent prepared by mixing methyl ethyl ketone and propylene glycol methyl ether acetate in a volume ratio of 1:1.5, the crosslinking agent is HDI trimer, the dispersant is a mixture of propylene glycol methyl ether and polyvinylpyrrolidone with a mass ratio of 1:2.5, the filler is silica with a particle size of 80 - 120 nm, and the titanate coupling agent is isopropyl tri-stearoyl titanate (KR-TTS);
[0101] Spray the prepared nano-silver-based paste on the bottom layer formed in step S2, keep it at 85 °C for 25 min, then heat it up to 125 °C and keep it for 20 min, and then heat it up to 155 °C and keep it for 15 min to cure and form a surface layer with a thickness of 0.2 mm, thus forming a nano-silver-based metal protective coating composed of a bottom layer and a surface layer on the metal substrate.
[0102] Example 2
[0103] A preparation method of a nano-silver-based metal protective coating includes the following steps:
[0104] S1. First, clean and degrease the metal substrate, then spray alumina sand grains with a mesh size of 80 - 120 to form a rough surface with a roughness of 2 μm, then soak it in a 20 wt% hydrochloric acid solution for 10 min for pickling, then immerse it in a 5 wt% sodium carbonate solution for 30 s for neutralization and then wash it with water, and dry it to obtain a pretreated substrate;
[0105] S2. Mix carboxyl silane, waterborne epoxy resin and water in a mass ratio of 1:4:1 to obtain a transition layer solution, and the carboxyl silane is γ-carboxypropyltrimethoxysilane;
[0106] Then spray the transition layer solution on the surface of the pretreated substrate in step S1, and keep it at 120 °C for 20 min to form a bottom layer with a thickness of 0.1 mm;
[0107] S3. Mix 20 kg of hydroxyl acrylic resin, 50 kg of waterborne epoxy resin, 15 kg of vinyl resin and 10 kg of solvent to obtain a preliminary mixture; mix 5 kg of titanate coupling agent, 3 kg of dispersant, 3 kg of crosslinking agent, 5 kg of filler and 10 kg of modified nano-silver particles prepared in Preparation Example 2, and then add them to the preliminary mixture and stir under vacuum conditions to obtain a nano-silver-based paste;
[0108] Among them, the solvent is a mixed solvent prepared by mixing methyl ethyl ketone and propylene glycol methyl ether acetate in a volume ratio of 1:1, the crosslinking agent is HDI trimer, the dispersant is a mixture of propylene glycol methyl ether and polyvinylpyrrolidone with a mass ratio of 1:2, the filler is silica with a particle size of 80 - 120 nm, and the titanate coupling agent is isopropyl tri-stearoyl titanate (KR-TTS);
[0109] The nano-silver-based paste prepared by spraying on the bottom layer formed in step S2 is kept at 80 °C for 30 min, then heated to 120 °C and kept for 25 min, and then heated to 150 °C and kept for 20 min to cure and form a surface layer with a thickness of 0.2 mm, thereby forming a nano-silver-based metal protective coating composed of a bottom layer and a surface layer on the metal substrate.
[0110] Example 3
[0111] A preparation method of a nano-silver-based metal protective coating includes the following steps:
[0112] S1. First, clean and degrease the metal substrate, then spray alumina sand grains with 80-120 meshes to form a rough surface with a roughness of 2 μm, then soak it in a 20 wt% hydrochloric acid solution for 10 min for pickling, then immerse it in a 5 wt% sodium carbonate solution for 30 s for neutralization, and then wash it with water and dry it to obtain a pretreated substrate;
[0113] S2. Mix carboxyl silane, waterborne epoxy resin and water according to a mass ratio of 1:6:1.5 to obtain a transition layer solution, and the carboxyl silane is selected as γ-carboxypropyltrimethoxysilane;
[0114] Then spray the transition layer solution on the surface of the pretreated substrate in step S1, and keep it at 130 °C for 10 min to form a bottom layer with a thickness of 0.1 mm;
[0115] S3. Mix 30 kg of hydroxyl acrylic resin, 70 kg of waterborne epoxy resin, 30 kg of vinyl resin and 25 kg of solvent to obtain a preliminary mixture; mix 10 kg of titanate coupling agent, 8 kg of dispersant, 5 kg of crosslinking agent, 10 kg of filler and 20 kg of modified nano-silver particles prepared in Preparation Example 3, and then add them to the preliminary mixture and stir under vacuum conditions to obtain a nano-silver-based paste;
[0116] Among them, the solvent is selected as a mixed solvent prepared by mixing methyl ethyl ketone and propylene glycol methyl ether acetate according to a volume ratio of 1:2, the crosslinking agent is selected as HDI trimer, the dispersant is selected as a mixture of propylene glycol methyl ether and polyvinylpyrrolidone with a mass ratio of 1:3, the filler is selected as silica with a particle size of 80-120 nm, and the titanate coupling agent is selected as isopropyl tri-stearoyl titanate (KR-TTS);
[0117] The nano-silver-based paste prepared by spraying on the bottom layer formed in step S2 is kept at 90 °C for 20 min, then heated to 130 °C and kept for 15 min, and then heated to 160 °C and kept for 10 min to cure and form a surface layer with a thickness of 0.2 mm, thereby forming a nano-silver-based metal protective coating composed of a bottom layer and a surface layer on the metal substrate.
[0118] Examples 4-8
[0119] A preparation method of a nano silver-based metal protective coating is carried out according to the method in Example 1, except that in step S3, the modified nano silver particles are added in the form of modified nano silver-silica composite particles prepared after post-treatment according to the methods in Preparation Examples 4-8.
[0120] Comparative Example 1
[0121] A preparation method of a nano silver-based metal protective coating is carried out according to the method in Example 1, except that step S2 treatment is not carried out, and the pre-treated substrate in step S1 is directly subjected to the operation in step S3 to spray the nano silver-based slurry.
[0122] Comparative Example 2
[0123] A preparation method of a nano silver-based metal protective coating is carried out according to the method in Example 1, except that in step S3, the modified nano silver particles in the nano silver-based slurry are replaced with nano silver particles in equal amounts.
[0124] Comparative Examples 3-4
[0125] A preparation method of a nano silver-based metal protective coating is carried out according to the method in Example 1, except that in step S3, the modified nano silver particles in the nano silver-based slurry are respectively selected as the modified nano silver particles prepared in Comparative Preparation Example 1 and Comparative Preparation Example 2.
[0126] Performance detection
[0127] Prepare the nano silver-based metal protective coating according to the methods in the examples and comparative examples of this application, and conduct a pull-out test in combination with ASTM D4541 to measure the bonding strength between the coating and the substrate, and place it in the culture media of Escherichia coli and Staphylococcus aureus for 7 days, then measure the diameter of the antibacterial circle to evaluate its antibacterial property and antibacterial persistence. The test results are shown in Table 1 below.
[0128] Table 1:
[0129]
[0130] Based on the test results in Table 1 above, the metal protective coating prepared in the embodiments of the present application has excellent bonding properties with the metal substrate, better adhesion, which helps to maintain the integrity of the coating, and thus can have a more lasting antibacterial effect. It has good antibacterial properties. Referring to the test results of Example 1 and Examples 4-6, when the prepared modified nano silver particles are loaded on silica and added after silane treatment, not only can the bonding strength be further improved, but also due to the slow release effect of silica, the antibacterial effect is further improved after long-term treatment, and it has better antibacterial persistence. Combining the test results of Example 7 and Example 8, when the modified nano silver particles are loaded on silica and only treated with γ-methacryloxypropyltrimethoxysilane or glycidoxypropyltrimethoxysilane, the antibacterial effect is less affected, but the bonding strength is significantly reduced.
[0131] Referring again to the test results of Example 1 and Comparative Example 1, it can be seen that when the metal substrate is directly top-coated without bottom treatment, the bonding strength is significantly reduced, and due to the reduction of the coating bonding strength, the antibacterial effect is also reduced. Combining the test results of Comparative Example 2, when the nano silver particles are not modified, they agglomerate seriously and the dispersion uniformity is poor, which affects the bonding strength and antibacterial effect. The bonding strength is significantly reduced, and the antibacterial effect is also reduced, which affects the adhesion between the surface layer and the substrate, and further affects the antibacterial effect. Combining the test results of Comparative Example 3 and Comparative Example 4, when the nano silver particles in Comparative Example 3 are not treated with mercapto groups during modification, both the bonding strength and the antibacterial effect are reduced. When the amino acrylate is replaced by amino silane in Comparative Example 4, the bonding strength is also reduced.
[0132] This specific embodiment is only an explanation of the present application and does not limit the present application. Those skilled in the art can make modifications without creative contributions to this embodiment after reading this specification, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.
Claims
1. A preparation method of a nano-silver-based metal protective coating, characterized in that, It includes the following steps: S1. First, clean and degrease the metal substrate, and then perform sandblasting and pickling treatment to obtain a pretreated substrate; S2. Coat a transition layer solution on the surface of the pretreated substrate, and after curing, form a bottom layer. The transition layer solution is prepared from carboxyl silane, waterborne epoxy resin, and water; S3. Spray a nano-silver-based slurry on the bottom layer, and after curing, form a top layer, and form a nano-silver-based metal protective coating composed of a bottom layer and a top layer on the metal substrate; Among them, the nano-silver-based slurry includes the following raw materials by weight: 20-30 parts of hydroxy-containing acrylic resin, 50-70 parts of waterborne epoxy resin, 15-30 parts of vinyl resin, 5-10 parts of titanate coupling agent, 3-8 parts of dispersant, 3-5 parts of crosslinking agent, 5-10 parts of filler, 10-25 parts of solvent, and 10-20 parts of modified nano-silver particles; Among them, the modified nano-silver particles are prepared by first treating nano-silver particles with mercapto silane and then grafting with aminoacrylate; 2. The preparation method of a nano-silver-based metal protective coating according to claim 1, characterized in that: In step S2, γ-carboxypropyltrimethoxysilane or γ-carboxypropyltriethoxysilane is selected as the carboxyl silane in the transition layer solution; In step S3, 3-mercaptopropyltrimethoxysilane is selected as the mercapto silane in the nano-silver-based slurry, and the aminoacrylate is a mixture of amino(meth)acrylate and γ-aminopropyltriethoxysilane; 3. The preparation method of a nano-silver-based metal protective coating according to claim 1, characterized in that: The modified nano-silver particles are prepared by the following method: 1). Dissolve mercapto silane in an ethanol aqueous solution, stir to generate a hydrolyzed silane solution, then add nano-silver particles, ultrasonically disperse at 50-60 °C for 20-30 min, and then centrifuge and wash with alcohol to obtain an inner-layer modified nano-silver intermediate; 2). Disperse the obtained inner-layer modified nano-silver intermediate in a mixed solution of propylene glycol monomethyl ether acetate and ethanol aqueous solution, then add aminoacrylate and genipin, raise the temperature to 60-70 °C, stir and react for 1-2 h, and then wash with alcohol, centrifuge, and dry to obtain modified nano-silver particles; 4. The preparation method of a silver nanometer-based metal protective coating according to claim 3, characterized in that: When preparing the modified nano-silver particles, the mass ratio of mercapto silane to ethanol aqueous solution added in step 1) is 1:(8-10), and the ethanol aqueous solution is a 40-50 wt% ethanol solution. The mass ratio of nano-silver particles to mercapto silane added is 1:(0.2-0.3); In step 2), the mass ratio of propylene glycol monomethyl ether acetate to ethanol aqueous solution added is 1:(0.6-0.8), and the ethanol aqueous solution is a 40-50 wt% ethanol solution; The mass ratio of the inner-layer modified nano-silver intermediate to the mixed solution added is 1:(6-8). The aminoacrylate is a mixture of amino(meth)acrylate and γ-aminopropyltriethoxysilane with a mass ratio of 1:(0.5-0.8), and the addition amount of aminoacrylate is 5-8 wt% of the inner-layer modified nano-silver intermediate, and the addition amount of genipin is 0.3-0.8 wt% of the inner-layer modified nano-silver intermediate; 5. The preparation method of a nano-silver-based metal protective coating according to claim 1, characterized in that: The modified nano-silver particles are also post-treated to form modified nano-silver-silica composite particles before adding. The specific post-treatment operation is: load the modified nano-silver particles on a silica carrier and then perform modification treatment with γ-methacryloxypropyltrimethoxysilane and glycidoxypropyltrimethoxysilane.
6. The preparation method of a nano-silver-based metal protective coating according to claim 3, characterized in that: The specific post-treatment operation of the modified nano-silver particles is as follows: 3), Disperse silica in an ethanol solution, add 3-aminopropyltrimethoxysilane, and stir for 30-40 min to obtain a pretreated silica solution; 4), Disperse the modified nano-silver particles in ethanol, then add the pretreated silica solution, ultrasonically disperse for 20-30 min, add γ-methacryloxypropyltrimethoxysilane and glycidyl ether oxypropyltrimethoxysilane, stir, centrifuge, wash, and dry to obtain silver-silica composite particles.
7. The preparation method of a nano silver-based metal protective coating according to claim 6, characterized in that: During the post-treatment of the modified nano-silver particles, in step 3), the addition amount of the ethanol solution is 4-6 mass times that of the silica addition amount, and the mass concentration of the ethanol solution is 40-50%, and the addition amount of 3-aminopropyltrimethoxysilane is 3-5 wt% of the silica; In step 4), the mass ratio of the modified nano-silver particles to the silica addition amount is 1:(1.8-2.2), the addition amount of γ-methacryloxypropyltrimethoxysilane is 3-5 wt% of the modified nano-silver particles, and the addition amount of glycidyl ether oxypropyltrimethoxysilane is 3-8 wt% of the modified nano-silver particles.
8. The preparation method of a nano-silver-based metal protective coating according to claim 1, characterized in that: The transition layer solution is prepared by mixing carboxysilane, waterborne epoxy resin, and water in a mass ratio of 1:(4-6):(1-1.5).
9. The preparation method of a silver nano-particle-based metal protective coating according to claim 1, wherein: The dispersant is a mixture of propylene glycol methyl ether and polyvinylpyrrolidone with a mass ratio of 1:(2-3); The filler is selected from one or more of talcum powder, silica, and calcium carbonate; The crosslinking agent is selected from HDI trimers.
10. A nano-silver-based metal protective coating prepared by the preparation method according to any one of claims 1-9.