Ceramic coating for metal doors and method for its preparation

Abstract

The application discloses a ceramic paint for metal doors and a preparation method thereof, and relates to the technical field of paints. The ceramic paint prepared by the application contains sodium silicate, methyltrimethoxysilane, modified polyacrylate emulsion, modified silicon dioxide, glass powder, sodium fluorosilicate, dispersant, leveling agent and pure water. The modified polyacrylate emulsion is obtained by polymerizing phosphorus-containing monomers and vinyl monomers to generate polyacrylate, reacting the polyacrylate with 5-chloromethyl-2-pyrimidine amine after sulfonyl chlorination, and then emulsifying. The silicon dioxide is obtained by polymerizing aniline on the surface of pretreated silicon dioxide, reacting with 1-benzothiophene-5-carbonyl chloride, then salifying with diphenyl iodonium triflate and copper acetate, and then reacting with bis(2-ethynylphenyl) sulfane. The ceramic paint prepared by the application has good corrosion resistance, antibacterial property and anti-aging property, and greatly improves the performance of the metal door.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-performance coatings, in particular to a ceramic coating with high performance for metal doors and a preparation method thereof. BACKGROUND

[0002] In the field of metal door manufacturing and application, the selection of surface coating is of vital importance to the durability, aesthetics, and functionality of the product. Traditional metal doors often use organic coatings or ordinary metal coatings for surface treatment. However, with the advancement of industrial technology and the increasing demand for product performance from users, the limitations of traditional coatings have gradually emerged. Ceramic coatings, as a new type of surface treatment material, have gradually gained attention. Ceramic coatings have been widely used in various industries due to their excellent high-temperature resistance, wear resistance, corrosion resistance, and good insulation performance. In the application of metal doors, ceramic coatings not only provide more durable surface protection but also enhance the overall performance of the product through their unique physical and chemical properties.

[0003] Despite the many advantages of ceramic coatings, such as high-temperature resistance, non-stickiness, corrosion resistance, and aesthetically pleasing appearance, it also has some drawbacks, the most significant of which is the brittleness and relatively poor wear resistance of the ceramic coating. In high-frequency use and outdoor light conditions, the coating may wear out, exposing the metal substrate and losing its original corrosion resistance and non-stickiness.

[0004] To overcome these shortcomings, ceramic coatings need to have stronger corrosion resistance, UV aging resistance, and antibacterial properties. Corrosion resistance can extend the service life of the coating and protect the substrate from corrosion. UV aging resistance ensures that the coating maintains its performance and appearance when exposed to outdoor environments for a long time. Antibacterial properties effectively prevent the growth of bacteria, mold, and other microorganisms on the surface of the coating, maintaining the cleanliness and hygiene of the coating. SUMMARY

[0005] The present application aims to provide a ceramic coating with high performance for metal doors and a preparation method thereof to solve the problems in the prior art.

[0006] To solve the above technical problems, the present application provides the following technical solutions:

[0007] A ceramic coating for metal doors, the ceramic coating, comprising sodium silicate, methyltrimethoxysilane, modified polyacrylate emulsion, modified silica, glass powder, sodium fluorosilicate, dispersant, leveling agent, and pure water.

[0008] The modified polyacrylate emulsion is obtained by polymerizing phosphorus-containing monomer and vinyl monomer to form polyacrylate, reacting the polyacrylate with sulfonyl chloride and 5-chloromethyl-2-pyrimidine amine after sulfuryl chlorination, and then emulsifying the modified polyacrylate.

[0009] The silica is obtained by polymerizing aniline on the surface of pretreated silica, then reacting with 1-benzothiophene-5-carbonyl chloride, and then salifying with diphenyl iodonium triflate and copper acetate, and then reacting with bis(2-ethynylphenyl) sulfane.

[0010] A preparation method of a ceramic paint for metal doors, comprising the following preparation steps:

[0011] (1) reacting vinyl diphenyl phosphorus with fuming sulfuric acid to obtain a phosphorus-containing monomer;

[0012] (2) polymerizing methyl acrylate, the phosphorus-containing monomer and styrene to obtain polyacrylate;

[0013] (3) reacting the polyacrylate, chlorosulfonic acid and sulfoxide chloride to obtain a pre-modified polyacrylate; reacting the pre-modified polyacrylate with 5-chloromethyl-2-pyrimidine amine to obtain a modified polyacrylate; and emulsifying the modified polyacrylate with an emulsifier to obtain a modified polyacrylate emulsion;

[0014] (4) reacting silica and 3-[3-(trimethoxysilyl) propoxy] aniline to obtain pretreated silica; polymerizing aniline on the surface of the pretreated silica to obtain polyaniline-based silica; and reacting the polyaniline-based silica with 1-benzothiophene-5-carbonyl chloride to obtain benzothiophene-based silica;

[0015] (5) reacting the benzothiophene-based silica with diphenyl iodonium triflate and copper acetate to obtain thiophene salt silica; and reacting the thiophene salt silica with ethanol and sodium ethoxide to obtain pre-modified silica;

[0016] (6) mixing the pre-modified silica, cuprous chloride, acetonitrile, triethylamine and iodoethyl benzoate, and then adding a bis(2-ethynylphenyl) sulfane solution at a dropping rate of 0.6 mL / min; after the addition is completed, continuing to stir for 30-40 min, filtering, washing and drying at room temperature to obtain modified silica;

[0017] (7) weighing the following components: sodium silicate, methyltrimethoxysilane, modified polyacrylate emulsion, modified silica, glass powder, sodium fluosilicate, dispersant, leveling agent and pure water; stirring the above components at 50-60°C for 30 min, then mixing in a high-speed mixer for 60-70 min, grinding in a grinder until the fineness reaches 40-50 μm, to obtain a ceramic paint.

[0018] As optimization, the preparation method of the phosphorus-containing monomer in step (1) is as follows: vinyl diphenyl phosphorus and fuming sulfuric acid are mixed at a mass ratio of 1:(2-2.5) at 0°C, stirred for 2 h at 0°C, stirred for 16-18 h after being warmed to room temperature, then cooled to 0°C, and then pure water is added dropwise at a drop rate of 1 mL / min, and the amount of pure water added is 15-20 times that of the vinyl diphenyl phosphorus; a 7.5M sodium hydroxide solution is used to adjust the pH to 7, filtration and recrystallization are performed using pure water at 4°C, filtration and washing are performed 3-4 times using n-pentane, and normal temperature drying is performed to obtain the phosphorus-containing monomer; the fuming sulfuric acid contains 25wt% of sulfur trioxide.

[0019] As optimization, the preparation method of the polyacrylate in step (2) is as follows: methyl acrylate, the phosphorus-containing monomer, styrene, and N,N-dimethylformamide are mixed at a mass ratio of 1:(0.6-0.8):(0.1-0.2):(20-30), warmed to 90°C under nitrogen protection, then 0.01 times the mass of benzoyl peroxide of the methyl acrylate is added and stirred for 90 min, 0.01 times the mass of benzoyl peroxide of the methyl acrylate is continuously added and stirred for 90 min, and then vacuum drying is performed at 80°C for 12 h to obtain the polyacrylate.

[0020] As optimization, the preparation method of the modified polyacrylate emulsion in step (3) is as follows: the polyacrylate, chlorosulfonic acid, thionyl chloride, phosphorus trichloride, and N,N-dimethylformamide are mixed at a mass ratio of 1:(0.2-0.3):(0.2-0.3):(0.06-0.08):(30-40), warmed to 55°C and reacted for 2 h, cooled to room temperature, and then an ice water mixture of 3-4 times the mass of N,N-dimethylformamide is added, filtration and washing are performed 3-4 times using pure water at 4°C, and vacuum drying is performed to obtain a pre-modified polyacrylate; the pre-modified polyacrylate, 5-chloromethyl-2-pyrimidine amine, dichloromethane, and triethylamine are mixed at a mass ratio of 1:(0.2-0.3):(20-30):(0.2-0.3) at room temperature and reacted for 5-6 h, and then vacuum rotary evaporation is performed after the reaction to obtain the modified polyacrylate; the modified polyacrylate, an emulsifier, pure water, and ethylene glycol butyl ether are weighed at a mass ratio of 1:0.3:40:5, the modified polyacrylate and the ethylene glycol butyl ether are mixed for 5 min, the emulsifier and the pure water are added, and then uniform mixing is performed at 70°C and 1000 r / min to obtain the modified polyacrylate emulsion; the emulsifier is OP-10.

[0021] As optimization, the preparation method of the benzothiophene-based silica in step (4) is as follows: mixing silica, 3-[3-(trimethoxysilyl)propoxy]aniline and anhydrous ethanol in a mass ratio of 1:(5-6):(50-60), ultrasonic oscillation for 20-30 min, warming to 50℃, stirring for 1-2 h, filtering and washing with pure water for 3-4 times, drying at 60℃ for 6-8 h to obtain pretreated silica; mixing the pretreated silica and 2wt% polyvinylpyrrolidone solution at 2-4℃, adding 0.6mol / L hydrochloric acid aqueous solution, aniline and ammonium persulfate, continuing to stir for 5-6 h, filtering and washing with anhydrous ethanol for 3-4 times, drying at 60℃ for 6-8 h to obtain polyaniline-based silica, and the mass ratio of the pretreated silica, aniline, 2wt% polyvinylpyrrolidone solution, 0.6mol / L hydrochloric acid aqueous solution and ammonium persulfate is 1:(0.5-0.6):(50-60):(25-30):(0.3-0.5); mixing the polyaniline-based silica, 1-benzothiophene-5-carbonyl chloride, N,N-dimethylformamide and triethylamine in a mass ratio of 1:(0.1-0.2):(20-30):(0.2-0.3), warming to 70-80℃ and stirring for 2-3 h, filtering and washing with anhydrous ethanol for 3-4 times, drying at room temperature for 6-8 h to obtain benzothiophene-based silica; the mesh number of the silica is 325 mesh.

[0022] As optimization, the preparation method of the pretreated silica in step (5) is as follows: mixing benzothiophene-based silica, diphenyl iodonium triflate and copper acetate in a mass ratio of 1:(0.2-0.3):0.02 to obtain a mixture, placing the mixture in a ball mill for mixing for 30 min, the ball-to-material ratio of the ball mill is 1:1, the rotation speed of the ball mill is 300r / min, after ball milling, taking out, stirring at 130-140℃ for 30 min, the stirring speed is 500-600r / min, after stirring, washing with dichloromethane for 5-6 times, drying at 60℃ for 6-8 h to obtain thiophene salt silica; mixing the thiophene salt silica, ethanol and sodium ethoxide in a mass ratio of 1:(20-30):(0.3-0.4), stirring at room temperature for 2 h, filtering and washing, and drying at room temperature to obtain pretreated silica.

[0023] As optimization, the solution of bis(2-ethynylphenyl)sulfane is obtained by mixing bis(2-ethynylphenyl)sulfane and acetonitrile in a mass ratio of 1:5; the mass ratio of the pretreated silica, cuprous chloride, acetonitrile, triethylamine, diethyl iodo benzene and the solution of bis(2-ethynylphenyl)sulfane is 1:(0.2-0.3):(20-30):(0.3-0.4):0.2:0.5.

[0024] As optimization, the component in step (7) is used in an amount of: 20-30 parts of sodium silicate, 1-2 parts of methyl trimethoxysilane, 20-30 parts of modified polyacrylate emulsion, 10-15 parts of modified silica, 10-15 parts of glass powder, 1-2 parts of sodium fluorosilicate, 1-2 parts of dispersant, 1-2 parts of leveling agent, and 20-30 parts of pure water.

[0025] As optimization, the solid content of sodium silicate in step (7) is 34%; the mesh number of the glass powder is 3000 mesh; the dispersant is BYK-2100; and the leveling agent is BYK-310.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] The ceramic paint for metal doors prepared by the present application comprises sodium silicate, methyl trimethoxysilane, modified polyacrylate emulsion, modified silica, glass powder, sodium fluorosilicate, dispersant, leveling agent, and pure water; the modified polyacrylate emulsion is obtained by polymerizing a phosphorus-containing monomer and a vinyl monomer to form polyacrylate, sulfuryl chlorinating the polyacrylate, reacting with 5-chloromethyl-2-pyrimidine amine, and then emulsifying; and the silica is obtained by polymerizing aniline on the surface of pretreated silica, reacting with 1-benzothiophene-5-carbonyl chloride, sulfuryl chlorinating with diphenyl iodonium triflate and copper acetate, and then reacting with bis(2-ethynylphenyl) sulfane.

[0028] First, a phosphorus-containing monomer and a vinyl monomer are polymerized by free radical initiation to form polyacrylate; the phosphorus-containing monomer is vinyl diphenyl phosphorus containing a sodium sulfonate functional group, which is converted into sulfuryl chloride in the presence of chlorosulfonic acid and sulfuric chloride, and the sulfuryl chloride reacts with the amino group on 5-chloromethyl-2-pyrimidine amine, thereby generating a sulfadiazine structure, which has inhibitory effect on most gram-negative bacteria and gram-positive bacteria, and can provide good antibacterial effect for the paint; in addition, the phosphorus element and the nitrogen element can synergistically flame retard, thereby providing certain flame retardant performance for the paint.

[0029] Secondly, the silane coupling agent containing aniline functional group is used to pretreat the silica, and the aniline is polymerized on the surface of the pretreated silica to generate polyaniline with conductive performance, the polyaniline has reversible oxidation and reduction property, can oxidize the metal to form a dense passivation layer, and inhibit the further corrosion of the metal, thereby protecting the metal substrate and providing good corrosion resistance for the coating; the 1-benzothiophene-5-carbonyl chloride introduces the benzothiophene functional group on the surface of the silica through the reaction of acyl chloride and the secondary amine group on the polyaniline, the benzothiophene functional group generates aryl sulfonium salt in the presence of diaryl iodonium salt, and then is opened in an alkaline condition to obtain a sulfide containing terminal alkyne, and then, in the presence of an oxidant and a catalyst, the aryl sulfide group and the di-alkynyl group generate a large conjugated structure, which has good absorption effect on ultraviolet rays, thereby providing good anti-aging ability to ultraviolet rays.

[0030] Finally, the sodium silicate, methyltrimethoxysilane, modified polyacrylate emulsion, modified silica, glass powder, sodium fluosilicate, dispersant, leveling agent and pure water are mixed to obtain the ceramic coating, the chloromethyl structure in the modified polyacrylate emulsion can react with the polyaniline on the surface of the modified silica, thereby increasing the crosslinking sites and further improving the compactness and mechanical properties of the coating.

[0031] The ceramic coating provided by the application can greatly improve the corrosion resistance, antibacterial property and anti-aging property of the metal door, and solves the problems existing in the long-term exposure of the metal door to various environments. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0033] In the following examples and comparative examples, the sodium silicate has a solid content of 34%, which is purchased from Qingdao Gulf Group; the glass powder has a mesh number of 3000, which is purchased from Fuhua Mineral Material Co., Ltd.; the dispersant has a model number of BYK-2100, which is purchased from BYK-Chemical Co., Ltd.; the leveling agent has a model number of BYK-310, which is purchased from BYK-Chemical Co., Ltd.; the bis(2-ethynylphenyl)sulfane solution is obtained by mixing bis(2-ethynylphenyl)sulfane and acetonitrile at a mass ratio of 1:5; the fuming sulfuric acid contains 25wt% of sulfur trioxide; the silica has a mesh number of 325; and the emulsifier is OP-10.

[0034] Example 1:

[0035] A preparation method of a ceramic paint for a metal door, the preparation method of the ceramic paint comprising the following preparation steps:

[0036] (1) mixing vinyl diphenyl phosphine and fuming sulfuric acid at a mass ratio of 1:2 at 0°C, stirring for 2 h at 0°C, stirring for 18 h after warming to room temperature, cooling to 0°C, adding pure water at a drop rate of 1 mL / min, the amount of pure water being 15 times that of the vinyl diphenyl phosphine, adjusting the pH to 7 using a 7.5M sodium hydroxide solution, filtering and recrystallizing using pure water at 4°C, filtering and washing 3 times using n-pentane, and obtaining a phosphorus-containing monomer through normal temperature drying;

[0037] (2) mixing methyl acrylate, the phosphorus-containing monomer, styrene, and N,N-dimethylformamide at a mass ratio of 1:0.6:0.1:20, warming to 90°C under nitrogen protection, then adding 0.01 times the mass of methyl acrylate of benzoyl peroxide and stirring for 90 min, continuously adding 0.01 times the mass of methyl acrylate of benzoyl peroxide and stirring for 90 min, after the stirring is completed, vacuum drying at 80°C for 12 h, and obtaining a polyacrylate;

[0038] (3) mixing the polyacrylate, chlorosulfonic acid, thionyl chloride, phosphorus trichloride, and N,N-dimethylformamide at a mass ratio of 1:0.2:0.2:0.06:30, warming to 55°C and reacting for 2 h, cooling to room temperature, adding 3 times the mass of N,N-dimethylformamide of an ice water mixture, filtering and washing 4 times using pure water at 4°C, vacuum drying to obtain a pre-modified polyacrylate; mixing the pre-modified polyacrylate, 5-chloromethyl-2-pyrimidine amine, dichloromethane, and triethylamine at a mass ratio of 1:0.2:20:0.2 and reacting at room temperature for 6 h, after the reaction is completed, rotary evaporation under reduced pressure to obtain a modified polyacrylate; weighing the modified polyacrylate, an emulsifier, pure water, and ethylene glycol butyl ether at a mass ratio of 1:0.3:40:5, mixing the modified polyacrylate and the ethylene glycol butyl ether for 5 min, adding the emulsifier and the pure water, uniformly mixing at 70°C and 1000 r / min, and obtaining a modified polyacrylate emulsion;

[0039] (4) mixing silica, 3-[3-(trimethoxysilyl)propoxy]aniline and anhydrous ethanol in a mass ratio of 1:5:50, ultrasonic oscillation for 30 min, warming to 50℃, stirring for 2 h, filtering and washing 4 times with pure water, drying at 60℃ for 8 h to obtain pretreated silica; taking pretreated silica, aniline, 2wt% polyvinylpyrrolidone aqueous solution, 0.6mol / L hydrochloric acid aqueous solution and ammonium persulfate in a mass ratio of 1:0.5:50:25:0.3; mixing pretreated silica and 2wt% polyvinylpyrrolidone aqueous solution at 4℃, adding 0.6mol / L hydrochloric acid aqueous solution, aniline and ammonium persulfate, continuing to stir for 6 h, filtering and washing 4 times with anhydrous ethanol, drying at 60℃ for 8 h to obtain polyaniline-based silica; mixing polyaniline-based silica, 1-benzothiophene-5-carbonyl chloride, N,N-dimethylformamide and triethylamine in a mass ratio of 1:0.1:20:0.2, warming to 80℃ and stirring for 3 h, filtering and washing 4 times with anhydrous ethanol, drying at room temperature for 8 h to obtain benzothiophene-based silica;

[0040] (5) mixing benzothiophene-based silica, diphenyl iodonium triflate and copper acetate in a mass ratio of 1:0.2:0.02 to obtain a mixture, placing the mixture in a ball mill for mixing for 30 min, the ball mill ball-to-material ratio being 1:1, the ball mill rotating speed being 300r / min, taking out after ball milling, stirring at 140℃ for 30 min, the stirring speed being 600r / min, after stirring, washing 6 times with dichloromethane, drying at 60℃ for 8 h to obtain thiophene salt silica; mixing thiophene salt silica, ethanol and sodium ethoxide in a mass ratio of 1:20:0.3, stirring at room temperature for 2 h, filtering, washing and drying at room temperature to obtain pre-modified silica;

[0041] (6) mixing pre-modified silica, cuprous chloride, acetonitrile, triethylamine and iodoethane diethyl ester, adding bis(2-ethynylphenyl)sulfane solution at a dropping speed of 0.6mL / min; after dropping, continuing to stir for 40 min, filtering, washing and drying at room temperature to obtain modified silica; the mass ratio of pre-modified silica, cuprous chloride, acetonitrile, triethylamine, iodoethane diethyl ester and bis(2-ethynylphenyl)sulfane solution is 1:0.2:20:0.3:0.2:0.5;

[0042] (7) taking the following components: sodium silicate 20 parts, methyltrimethoxysilane 1 part, modified polyacrylate emulsion 20 parts, modified silica 10 parts, glass powder 10 parts, sodium fluosilicate 1 part, dispersing agent 1 part, leveling agent 1 part, and pure water 20 parts; stirring the above components at 60℃ for 30 min, then mixing in a high-speed mixer for 70 min, grinding in a grinder to a fineness of 50μm to obtain a ceramic coating.

[0043] Example 2:

[0044] A preparation method of a ceramic paint for a metal door, the preparation method of the ceramic paint comprising the following preparation steps:

[0045] (1) mixing vinyl diphenyl phosphine and fuming sulfuric acid at a mass ratio of 1:2.3 at 0°C, stirring for 2 h at 0°C, stirring for 17 h after warming to room temperature, and then cooling to 0°C, adding pure water at a drop rate of 1 mL / min, the amount of pure water being 17 times that of the vinyl diphenyl phosphine; adjusting the pH to 7 using a 7.5M sodium hydroxide solution, filtering and recrystallizing using pure water at 4°C, filtering and washing 3 times using n-pentane, and drying at room temperature to obtain a phosphorus-containing monomer;

[0046] (2) mixing methyl acrylate, the phosphorus-containing monomer, styrene, and N,N-dimethylformamide at a mass ratio of 1:0.7:0.15:25, warming to 90°C under nitrogen protection, then adding 0.01 times the mass of methyl acrylate of benzoyl peroxide and stirring for 90 min, continuously adding 0.01 times the mass of methyl acrylate of benzoyl peroxide and stirring for 90 min, and then drying at 80°C under vacuum for 12 h to obtain a polyacrylate;

[0047] (3) mixing the polyacrylate, chlorosulfonic acid, thionyl chloride, phosphorus trichloride, and N,N-dimethylformamide at a mass ratio of 1:0.25:0.25:0.07:35, warming to 55°C and reacting for 2 h, cooling to room temperature, adding 3 times the mass of N,N-dimethylformamide of an ice water mixture, filtering and washing 3 times using pure water at 4°C, and vacuum drying to obtain a pre-modified polyacrylate; mixing the pre-modified polyacrylate, 5-chloromethyl-2-pyrimidine amine, dichloromethane, and triethylamine at a mass ratio of 1:0.25:25:0.25 at room temperature and reacting for 5.5 h, and then vacuum rotary evaporation after the reaction to obtain a modified polyacrylate; weighing the modified polyacrylate, an emulsifier, pure water, and ethylene glycol butyl ether at a mass ratio of 1:0.3:40:5, mixing the modified polyacrylate and ethylene glycol butyl ether for 5 min, adding the emulsifier and pure water, and uniformly mixing at 70°C and 1000 r / min to obtain a modified polyacrylate emulsion;

[0048] (4) mixing silica, 3-[3-(trimethoxysilyl)propoxy]aniline, anhydrous ethanol in a mass ratio of 1:5.5:57, ultrasonic oscillation for 25 min, warming to 50℃, stirring for 1.5 h, filtering and washing 3 times with pure water, drying at 60℃ for 7 h to obtain pretreated silica; taking pretreated silica, aniline, 2wt% polyvinylpyrrolidone aqueous solution, 0.6mol / L hydrochloric acid aqueous solution, ammonium persulfate in a mass ratio of 1:0.55:56:27:0.4; mixing pretreated silica and 2wt% polyvinylpyrrolidone aqueous solution at 3℃, adding 0.6mol / L hydrochloric acid aqueous solution, aniline, ammonium persulfate and continuing to stir for 5.5 h, filtering and washing 3 times with anhydrous ethanol, drying at 60℃ for 7 h to obtain polyaniline-based silica; mixing polyaniline-based silica, 1-benzothiophene-5-carbonyl chloride, N,N-dimethylformamide, triethylamine in a mass ratio of 1:0.15:25:0.25, warming to 76℃ and stirring for 2.5 h, filtering and washing 3 times with anhydrous ethanol, drying at room temperature for 7 h to obtain benzothiophene-based silica;

[0049] (5) mixing benzothiophene-based silica, diphenyl iodonium triflate, copper acetate in a mass ratio of 1:0.25:0.02 to obtain a mixture, placing the mixture in a ball mill for mixing for 30 min, the ball mill ball-to-material ratio is 1:1, the ball mill rotation speed is 300r / min, after ball milling, taking out, stirring at 135℃ for 30 min, the stirring speed is 550r / min, after stirring, washing 5 times with dichloromethane, drying at 60℃ for 7 h to obtain thiophene salt silica; mixing thiophene salt silica, ethanol, sodium ethoxide in a mass ratio of 1:25:0.35, stirring at room temperature for 2 h, filtering, washing and drying at room temperature to obtain pre-modified silica;

[0050] (6) mixing pre-modified silica, cuprous chloride, acetonitrile, triethylamine, diethyl iodo benzene, and adding bis(2-ethynylphenyl)sulfane solution at a drop rate of 0.6mL / min; after drop completion, continuing to stir for 30 min, filtering, washing and drying at room temperature to obtain modified silica; the mass ratio of pre-modified silica, cuprous chloride, acetonitrile, triethylamine, diethyl iodo benzene and bis(2-ethynylphenyl)sulfane solution is 1:0.25:25:0.35:0.2:0.5;

[0051] (7) taking the following components: sodium silicate 23 parts, methyltrimethoxysilane 1.5 parts, modified polyacrylate emulsion 25 parts, modified silica 12 parts, glass powder 13 parts, sodium fluosilicate 1 part, dispersant 2 parts, leveling agent 2 parts, pure water 25 parts; stirring the above components at 55℃ for 30 min, then mixing in a high-speed mixer for 65 min, grinding in a grinder to a fineness of 45μm to obtain a ceramic coating.

[0052] Example 3:

[0053] A preparation method of a ceramic paint for a metal door, the preparation method of the ceramic paint comprising the following preparation steps:

[0054] (1) mixing vinyl diphenyl phosphine and fuming sulfuric acid at a mass ratio of 1:2.5 at 0°C, stirring for 2 h at 0°C, stirring for 16 h after warming to room temperature, and then cooling to 0°C, adding pure water at a drop rate of 1 mL / min, the amount of pure water being 20 times that of the vinyl diphenyl phosphine, adjusting the pH to 7 using a 7.5M sodium hydroxide solution, filtering and recrystallizing using pure water at 4°C, filtering and washing 4 times using n-pentane, and drying at room temperature to obtain a phosphorus-containing monomer;

[0055] (2) mixing methyl acrylate, the phosphorus-containing monomer, styrene, and N,N-dimethylformamide at a mass ratio of 1:0.8:0.2:30, warming to 90°C under nitrogen protection, then adding 0.01 times the mass of methyl acrylate of benzoyl peroxide and stirring for 90 min, continuously adding 0.01 times the mass of methyl acrylate of benzoyl peroxide and stirring for 90 min, and then drying at 80°C under vacuum for 12 h to obtain a polyacrylate;

[0056] (3) mixing the polyacrylate, chlorosulfonic acid, thionyl chloride, phosphorus trichloride, and N,N-dimethylformamide at a mass ratio of 1:0.3:0.3:0.08:40, warming to 55°C and reacting for 2 h, cooling to room temperature, adding 4 times the mass of N,N-dimethylformamide of an ice water mixture, filtering and washing 3 times using pure water at 4°C, and vacuum drying to obtain a pre-modified polyacrylate; mixing the pre-modified polyacrylate, 5-chloromethyl-2-pyrimidine amine, dichloromethane, and triethylamine at a mass ratio of 1:0.3:30:0.3 at room temperature and reacting for 5 h, then rotary evaporating under reduced pressure after the reaction to obtain a modified polyacrylate; weighing the modified polyacrylate, an emulsifier, pure water, and ethylene glycol butyl ether at a mass ratio of 1:0.3:40:5, mixing the modified polyacrylate and the ethylene glycol butyl ether for 5 min, then adding the emulsifier and the pure water, and uniformly mixing at 70°C and 1000 r / min to obtain a modified polyacrylate emulsion;

[0057] (4) mixing silica, 3-[3-(trimethoxysilyl)propoxy]aniline and anhydrous ethanol in a mass ratio of 1:6:60, ultrasonic oscillation for 20 min, warming to 50℃, stirring for 1 h, filtering and washing with pure water for 3 times, drying at 60℃ for 8 h to obtain pretreated silica; taking pretreated silica, aniline, 2wt% polyvinylpyrrolidone aqueous solution, 0.6mol / L hydrochloric acid aqueous solution and ammonium persulfate in a mass ratio of 1:0.6:60:30:0.5; mixing pretreated silica and 2wt% polyvinylpyrrolidone aqueous solution at 2℃, adding 0.6mol / L hydrochloric acid aqueous solution, aniline and ammonium persulfate, continuing to stir for 5 h, filtering and washing with anhydrous ethanol for 3 times, drying at 60℃ for 6 h to obtain polyaniline-based silica; mixing polyaniline-based silica, 1-benzothiophene-5-carbonyl chloride, N,N-dimethylformamide and triethylamine in a mass ratio of 1:0.2:30:0.3, warming to 70℃ and stirring for 2 h, filtering and washing with anhydrous ethanol for 3 times, drying at room temperature for 6 h to obtain benzothiophene-based silica;

[0058] (5) mixing benzothiophene-based silica, diphenyl iodonium triflate and copper acetate in a mass ratio of 1:0.3:0.02 to obtain a mixture, mixing the mixture in a ball mill for 30 min, the ball mill ball-to-material ratio is 1:1, the ball mill rotation speed is 300r / min, after ball milling, taking out, stirring at 130℃ for 30 min, the stirring speed is 500r / min, after stirring, washing with dichloromethane for 5 times, drying at 60℃ for 6 h to obtain thiophene salt silica; mixing thiophene salt silica, ethanol and sodium ethoxide in a mass ratio of 1:30:0.4, stirring at room temperature for 2 h, filtering, washing and drying at room temperature to obtain pre-modified silica;

[0059] (6) mixing pre-modified silica, cuprous chloride, acetonitrile, triethylamine and iodo benzene diethyl ester, adding bis(2-ethynylphenyl)sulfane solution at a drop rate of 0.6mL / min; after drop completion, continuing to stir for 30 min, filtering, washing and drying at room temperature to obtain modified silica; the mass ratio of pre-modified silica, cuprous chloride, acetonitrile, triethylamine, iodo benzene diethyl ester and bis(2-ethynylphenyl)sulfane solution is 1:0.3:30:0.4:0.2:0.5;

[0060] (7) taking the following components: sodium silicate 30 parts, methyltrimethoxysilane 2 parts, modified polyacrylate emulsion 30 parts, modified silica 15 parts, glass powder 15 parts, sodium fluosilicate 2 parts, dispersing agent 2 parts, leveling agent 2 parts, and pure water 30 parts; stirring the above components at 50℃ for 30 min, then mixing in a high-speed mixer for 60 min, grinding in a grinder to a fineness of 40μm to obtain a ceramic coating.

[0061] Comparative Example 1:

[0062] The preparation method of the ceramic coating of Comparative Example 1 is different from that of Example 2 in that step (3) is modified as follows: polyacrylate, emulsifier, pure water, and ethylene glycol butyl ether are weighed according to a mass ratio of 1:0.3:40:5, the modified polyacrylate and ethylene glycol butyl ether are mixed for 5 min, then the emulsifier and pure water are added, and mixing is performed at 70°C and 1000 r / min to obtain a modified polyacrylate emulsion.

[0063] Comparative Example 2:

[0064] The preparation method of the ceramic coating of Comparative Example 2 is different from that of Example 2 in that steps (5) to (6) are not included, and step (4) is modified as follows: silica, 3-[3-(trimethoxysilyl)propoxy]aniline, and anhydrous ethanol are mixed according to a mass ratio of 1:5.5:57, ultrasonic oscillation is performed for 25 min, the temperature is increased to 50°C, stirring is performed for 1.5 h, filtration is performed and washing is performed three times using pure water, and drying is performed at 60°C for 7 h to obtain pretreated silica; the pretreated silica, aniline, a 2wt% polyvinylpyrrolidone aqueous solution, a 0.6mol / L hydrochloric acid aqueous solution, and ammonium persulfate are weighed according to a mass ratio of 1:0.55:56:27:0.4; at 3°C, the pretreated silica and the 2wt% polyvinylpyrrolidone aqueous solution are mixed, the 0.6mol / L hydrochloric acid aqueous solution, aniline, and ammonium persulfate are added, and stirring is continued for 5.5 h, filtration is performed and washing is performed three times using anhydrous ethanol, and drying is performed at 60°C for 7 h to obtain modified silica.

[0065] Comparative Example 3:

[0066] The preparation method of the ceramic coating of Comparative Example 3 is different from that of Example 2 in that steps (4) to (6) are not included, and step (7) is modified as follows: the following components are weighed: sodium silicate 23 parts, methyltrimethoxysilane 1.5 parts, modified polyacrylate emulsion 25 parts, silica 12 parts, glass powder 13 parts, sodium fluorosilicate 1 part, dispersant 2 parts, leveling agent 2 parts, and pure water 25 parts; the above components are stirred at 55°C for 30 min, then mixed in a high-speed mixer for 65 min, ground in a grinder, and the fineness is adjusted to 45μm to obtain the ceramic coating.

[0067] Test Example 1:

[0068] Corrosion resistance test:

[0069] Test method: the ceramic coating prepared by the examples and the comparative examples was sprayed on the surface of tinplate by compressed air, and cured at room temperature to form a film. The pressure of the air compressor was 0.9 MPa, the nozzle diameter was 1.5 mm, the spraying angle was 45°, the coating thickness was 30 μm, and the coating was dried at room temperature for 24 h. The corrosion resistance of the coating was tested according to the standard GB T1763-1979. The chemical reagent was 20 wt% sodium hydroxide solution, the test time was 20 days, and the appearance of the coating was recorded. The results are shown in Table 1.

[0070] Table 1

[0071] Coating appearance Coating appearance Example 1 No blistering, rusting, peeling Comparative Example 1 No blistering, rusting, peeling Example 2 No blistering, rusting, peeling Comparative Example 2 No blistering, rusting, peeling Example 3 No blistering, rusting, peeling Comparative Example 3 Blistering

[0072] From the experimental data of Examples 1-3 and Comparative Examples 1-3 in Table 1, it can be found that the ceramic coating prepared by the present application has good corrosion resistance.

[0073] By comparison, the appearance of the coating of Examples 1-3 is better than that of Comparative Example 3, which shows that the use of silane coupling agent containing aniline functional group for pretreatment of silica, polymerization of aniline on the surface of pretreated silica to generate polyaniline with conductive properties, polyaniline has reversible oxidation and reduction properties, can oxidize metal to form a dense passivation layer, inhibit further corrosion of metal, thereby protecting the metal substrate and providing good corrosion resistance for the coating.

[0074] Test Example 2:

[0075] Test of antibacterial performance:

[0076] Test method: the ceramic coating prepared by the examples and the comparative examples was sprayed on the surface of tinplate by compressed air, and cured at room temperature to form a film. The pressure of the air compressor was 0.9 MPa, the nozzle diameter was 1.5 mm, the spraying angle was 45°, the coating thickness was 30 μm, and the coating was dried at room temperature for 24 h. The antibacterial performance of the coating was tested according to the standard GB / T21866-2008. The results are shown in Table 2.

[0077] Table 2

[0078] Antibacterial rate (%) Antibacterial rate (%) Example 1 96.74 Comparative Example 1 35.47 Example 2 97.03 Comparative Example 2 96.32 Example 3 97.16 Comparative Example 3 96.21

[0079] From the experimental data of Examples 1-3 and Comparative Examples 1-3 in Table 2, it can be found that the ceramic coating prepared by the present application has good antibacterial performance.

[0080] By comparison, the antibacterial rates of Examples 1-3 are greater than that of Comparative Example 1, which indicates that the phosphorus-containing monomer and the vinyl monomer are polymerized by free radical initiation to form a polyacrylate; the phosphorus-containing monomer is a vinyl diphenyl phosphorus containing a sodium sulfonate functional group, which is changed into sulfuryl chloride in the presence of chlorosulfonic acid and chlorosulfuric acid, and the sulfuryl chloride reacts with the amino group on 5-chloromethyl-2-pyrimidine amine to form a sulfadiazine structure, which has an inhibitory effect on most gram-negative bacteria and gram-positive bacteria, and can provide good antibacterial effect for the coating.

[0081] Test Example 3:

[0082] Test of the anti-UV aging performance:

[0083] Test method: the ceramic coating prepared from the examples and comparative examples is sprayed on the surface of a tinplate sheet by compressed air, and is cured at room temperature to form a film, the pressure of the air compressor is 0.9 MPa, the nozzle diameter is 1.5 mm, the spraying angle is 45°, the coating thickness is 30 μm, and the coating is dried at room temperature for 24 h. The anti-aging performance of the coating is tested according to the test method specified in Q / JLY J7110279 using a QUV ultraviolet accelerated aging test machine, and the test time is 1200 h. The impact resistance of the coating before and after ultraviolet aging is determined according to the standard GB / T 1732.1993, and the retention rate of the impact resistance is calculated. The results are shown in Table 3.

[0084] Table 3

[0085]

[0086]

[0087] From the experimental data of Examples 1-3 and Comparative Examples 1-3 in Table 3, it can be found that the ceramic coating prepared by the present application has good anti-UV aging performance.

[0088] The retention rate of Examples 1-3 is greater than that of Comparative Examples 2-3, which indicates that the silica is pretreated with a silane coupling agent containing an aniline functional group, the aniline is polymerized on the surface of the pretreated silica to form polyaniline, 1-benzothiophene-5-carbonyl chloride is introduced into the benzothiophene functional group on the surface of the silica by the reaction of the carbonyl chloride with the secondary amine group on the polyaniline, the benzothiophene functional group generates an aryl sulfonium salt in the presence of diaryl iodine salt, and then an alkynyl-containing thioether is obtained by ring opening under alkaline conditions, and then the arylthio group and the di-alkynyl group generate a large conjugated structure by coupling reaction in the presence of an oxidizing agent and a catalyst, which has a good absorption effect on ultraviolet rays, thereby providing good anti-UV aging ability for ultraviolet rays.

[0089] Due to long-term exposure of metal doors to various environments, the performance of the metal doors is prone to decline due to corrosion, aging and other problems. Moreover, the metal doors have high selling prices, and users expect long service life. How to improve the corrosion resistance and aging resistance of the metal doors has been a pain point in the industry. The ceramic coating provided by the present application can greatly improve the corrosion resistance, antibacterial property and aging resistance of the metal door, solve the technical problems existing in long-term exposure of the metal door to various environments, and has significant technical effects and high economic value.

[0090] It will be obvious to a person skilled in the art that, without departing from the spirit or essential characteristics of the application, the present application can be implemented in other specific forms. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the description above, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference signs in the claims should not be construed as limiting the claim.

Claims

1. A method for the preparation of a ceramic coating for metal doors, characterized by, The ceramic coating comprises sodium silicate, methyltrimethoxysilane, modified polyacrylate emulsion, modified silica, glass powder, sodium fluorosilicate, dispersant, leveling agent, and pure water; the modified polyacrylate emulsion is obtained by polymerizing phosphorus-containing monomers and vinyl monomers to generate polyacrylate, followed by sulfonyl chlorination and reaction with 5-chloromethyl-2-pyrimidinamine, and then emulsification; the silica is obtained by polymerizing aniline on a pretreated silica surface, reacting it with 1-benzothiophene-5-carbonyl chloride, followed by diphenyliodotrifluoromethanesulfonate and copper acetate salting, and then reacting it with bis(2-ethynylphenyl)thione. The preparation steps include the following: (1) React vinyl diphenylphosphine with fuming sulfuric acid to obtain a phosphorus-containing monomer; (2) Polymerize methyl acrylate, phosphorus-containing monomers, and styrene to obtain polyacrylate; (3) The pre-modified polyacrylate is obtained by reacting polyacrylate, chlorosulfonic acid and thionyl chloride; The pre-modified polyacrylate was reacted with 5-chloromethyl-2-pyrimidinamine to obtain the modified polyacrylate; the modified polyacrylate was emulsified with an emulsifier to obtain the modified polyacrylate emulsion. (4) Pretreated silica is obtained by reacting silica with 3-[3-(trimethoxysilyl)propoxy]aniline; polyaniline-based silica is obtained by polymerizing aniline on the surface of pretreated silica; and benzothiophene-5-carbonyl chloride is obtained by reacting polyaniline-based silica with 1-benzothiophene-5-carbonyl chloride. (5) Benzothiophene silica, diphenyliodotrifluoromethanesulfonate and copper acetate are reacted to obtain thiophene silica; thiophene silica, ethanol and sodium ethoxide are reacted to obtain pre-modified silica; (6) Mix pre-modified silica, cuprous chloride, acetonitrile, triethylamine and diethyl iodophenyl ester, and add bis(2-ethynylphenyl)thione solution dropwise at a rate of 0.6 mL / min; after the addition is complete, continue stirring for 30-40 min, filter, wash and dry at room temperature to obtain modified silica; (7) Weigh the following components: sodium silicate, methyltrimethoxysilane, modified polyacrylate emulsion, modified silica, glass powder, sodium fluorosilicate, dispersant, leveling agent, and pure water; stir the above components at 50-60℃ for 30 min, then mix them in a high-speed mixer for 60-70 min, and grind them in a grinder until the fineness reaches 40-50 μm to obtain ceramic coating; The preparation method of polyacrylate in step (2) is as follows: methyl acrylate, phosphorus-containing monomer, styrene, and N,N-dimethylformamide are mixed in a mass ratio of 1:(0.6-0.8):(0.1-0.2):(20-30). Under nitrogen protection, the mixture is heated to 90°C. Then, 0.01 times the mass of methyl acrylate and benzoyl peroxide are added and stirred for 90 min. Then, 0.01 times the mass of methyl acrylate and benzoyl peroxide are added and stirred for another 90 min. After stirring, the mixture is vacuum dried at 80°C for 12 h to obtain polyacrylate. The preparation method of the modified polyacrylate emulsion in step (3) is as follows: polyacrylate, chlorosulfonic acid, chlorosulfoxide, phosphorus trichloride, and N,N-dimethylformamide are mixed in a mass ratio of 1:(0.2-0.3):(0.2-0.3):(0.06-0.08):(30-40), heated to 55°C for 2h, cooled to room temperature, and then N,N-dimethylformamide is added in an amount of 3-4 times the mass of the ice water mixture, filtered and washed 3-4 times with pure water at 4°C, and then vacuum dried to obtain a pre-modified polyacrylate; the pre-modified polyacrylate, 5-chloromethyl-2-pyrimidine amine, dichloromethane, and triethylamine are mixed in a mass ratio of 1:(0.2-0.3):(20-30):(0.2-0.3) and reacted at room temperature for 5-6h, after the reaction is completed, the modified polyacrylate is obtained by rotary evaporation under reduced pressure; the modified polyacrylate, emulsifier, pure water, and ethylene glycol butyl ether are weighed in a mass ratio of 1:0.3:40:5, the modified polyacrylate and ethylene glycol butyl ether are mixed for 5min, then the emulsifier and pure water are added, and the mixture is uniformly mixed at 70°C and 1000r / min to obtain a modified polyacrylate emulsion; the emulsifier is OP-10. The preparation method of the pre-modified silicon dioxide in step (5) is as follows: benzothiophene-based silicon dioxide, diphenyl iodonium triflate, and copper acetate are mixed in a mass ratio of 1:(0.2-0.3):0.02 to obtain a mixture, the mixture is placed in a ball mill for mixing for 30min, the ball mill ball-to-material ratio is 1:1, and the ball mill rotation speed is 300r / min, after the ball milling is completed, the mixture is taken out, stirred at 130-140°C for 30min at a stirring speed of 500-600r / min, after the stirring is completed, the mixture is washed 5-6 times with dichloromethane, and then dried at 60°C for 6-8h to obtain thiophene salt silicon dioxide; the thiophene salt silicon dioxide, ethanol, and sodium ethoxide are mixed in a mass ratio of 1:(20-30):(0.3-0.4) and stirred at room temperature for 2h, then filtered and washed, and dried at room temperature to obtain pre-modified silicon dioxide.

2. A method for preparing a ceramic coating for metal doors according to claim 1, characterized in that, The preparation method of the phosphorus-containing monomer in step (1) is as follows: vinyl diphenyl phosphine and fuming sulfuric acid are mixed in a mass ratio of 1:(2-2.5) at 0°C, stirred at 0°C for 2h, then stirred at room temperature for 16-18h, cooled to 0°C again, and then pure water is added at a drop rate of 1mL / min, the amount of pure water added is 15-20 times that of vinyl diphenyl phosphine; the pH is adjusted to 7 using a 7.5M sodium hydroxide solution, the mixture is filtered and recrystallized using pure water at 4°C, then filtered and washed 3-4 times with n-pentane, and dried at room temperature to obtain the phosphorus-containing monomer; the fuming sulfuric acid contains 25wt% sulfur trioxide.

3. A method for preparing a ceramic coating for metal doors according to claim 1, characterized in that, The preparation method of the benzothiophene-based silica in step (4) is as follows: mixing silica, 3-[3-(trimethoxysilyl)propoxy]aniline, and anhydrous ethanol in a mass ratio of 1:(5-6):(50-60), ultrasonic oscillation for 20-30 min, heating to 50℃, stirring for 1-2 h, filtering, washing with pure water for 3-4 times, and drying at 60℃ for 6-8 h to obtain pretreated silica; mixing the pretreated silica and 2wt% polyvinylpyrrolidone solution at 2-4℃, adding 0.6mol / L hydrochloric acid aqueous solution, aniline, and ammonium persulfate, continuing to stir for 5-6 h, filtering, washing with anhydrous ethanol for 3-4 times, and drying at 60℃ for 6-8 h to obtain polyaniline-based silica; the mass ratio of the pretreated silica, aniline, 2wt% polyvinylpyrrolidone solution, 0.6mol / L hydrochloric acid aqueous solution, and ammonium persulfate is 1:(0.5-0.6):(50-60):(25-30):(0.3-0.5); mixing the polyaniline-based silica, 1-benzothiophene-5-carbonyl chloride, N,N-dimethylformamide, and triethylamine in a mass ratio of 1:(0.1-0.2):(20-30):(0.2-0.3), heating to 70-80℃, stirring for 2-3 h, filtering, washing with anhydrous ethanol for 3-4 times, and drying at room temperature for 6-8 h to obtain benzothiophene-based silica; the mesh number of the silica is 325 mesh.

4. A method of preparing a ceramic coating for a metal door according to claim 1, characterized in that, The solution of bis(2-ethynylphenyl)sulfane in step (6) is obtained by mixing bis(2-ethynylphenyl)sulfane and acetonitrile in a mass ratio of 1:5; the mass ratio of the pre-modified silica, cuprous chloride, acetonitrile, triethylamine, diethyl iodo benzene, and the solution of bis(2-ethynylphenyl)sulfane is 1:(0.2-0.3):(20-30):(0.3-0.4):0.2:0.

5.

5. A method of preparing a ceramic coating for a metal door according to claim 1, characterized in that, The use amount of the components in step (7) is as follows: sodium silicate 20-30 parts, methyltrimethoxysilane 1-2 parts, modified polyacrylate emulsion 20-30 parts, modified silica 10-15 parts, glass powder 10-15 parts, sodium fluosilicate 1-2 parts, dispersant 1-2 parts, leveling agent 1-2 parts, and pure water 20-30 parts.

6. A method of preparing a ceramic coating for a metal door according to claim 1, characterized in that, The solid content of the sodium silicate in step (7) is 34%; the mesh number of the glass powder is 3000 mesh; the type of the dispersant is BYK-2100; and the type of the leveling agent is BYK-310.

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