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5.9 KiB
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3 lines
5.9 KiB
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"protocol": "The synthesis of hydrophilic polymers involves a polycondensation reaction of a hydrolysate of an inorganic alkoxide in the presence of polyacrylic and polyvinyl alcohol. Additional components may include hydrosilicofluoric acid and a silane coupling agent having an epoxy group, or a specific benzophenone compound.Synthesize hydrophilic polymers by using alkoxides as precursors. Select an inorganic alkoxide compound from the formula M(OR)n(X)α-n, where M is an element such as Si, Al, Ti, or Zr, and R and X are appropriate alkyl groups or functional groups. For example, use Si(OR1)4 with R1 being a lower alkyl group (1 to 4 carbon atoms). Prepare mixtures using aluminum, titanium, or zirconium alkoxides in varying proportions to enhance properties such as light transmission, heat resistance, and toughness. Specifically, combine aluminum alkoxides in a ratio of 1 to 10 parts by weight per 100 parts by weight of alkoxysilane, titanium alkoxides in a ratio of 0.1 to 3 parts by weight, and zirconium alkoxides in a ratio of 0.5 to 5 parts by weight per 100 parts by weight of alkoxysilane. The use of functional groups in the X position, such as vinyl, carboxyl, carbonyl, amino, or epoxy, can enhance anti-fogging properties. Example compounds include vinyltrichlorosilane and γ-methacryloxypropyltrimethoxysilane. Employ polyacrylic and polyvinyl alcohol with specified saponification degrees to further modify the properties of the polymers.To synthesize hydrophilic polymers with functional groups, prepare a reaction solution containing at least one inorganic alkoxide, a hydrolysate of the inorganic alkoxide, and a low molecular weight polycondensate of the hydrolysate, along with a polyacrylic, polyvinyl alcohol, and a catalyst for accelerating the polycondensation reaction. The inorganic alkoxide can undergo hydrolysis and polycondensation either before or after the preparation of the reaction solution. Use an acid catalyst, preferably a mineral acid (e.g., hydrochloric acid, sulfuric acid, nitric acid) or organic acids, in an amount of 0.01 to 0.5 parts by weight per 100 parts by weight of the alkoxide. Add hydrosilicofluoric acid (0.005 to 0.5 parts by weight) and a silane coupling agent (0.05 to 10 parts by weight) such as γ-glycidoxypropyltrimethoxysilane to the mixture. Optionally, incorporate a benzophenone compound known for weather resistance properties. Mix the components to form a transparent coating fluid, apply it to a substrate, and dry under heating at 80°C or higher, preferably between 120°C to 200°C, to form an anti-fogging coating film with hydrophilic properties.A coating fluid was prepared by adding a 10% aqueous solution of polyvinyl alcohol (average polymerization degree: 2,000, saponification degree: about 82 mol%) to a 2.5% water-methanol solution of a 20 mol% saponified product of polymethyl acrylate. The saponified product was obtained by adding methanol to a 25% aqueous solution of polyacrylic acid (average molecular weight: 150,000), stirring the mixture at ordinary temperature (25°C) for 30 minutes to produce polymethyl acrylate, adding sodium hydroxide to achieve a saponification degree of 20%, and stirring for an additional 30 minutes to saponify the methyl ester. The resulting mixture was stirred at 25°C for 10 minutes, and then a solution of γ-glycidoxypropyl-trimethoxysilane, a solution of a hydrolysate of aluminum isopropoxide (5% by weight in terms of Al2O3), and a 0.47% methanol solution of hydrosilicofluoric acid were added. The mixture was stirred at 25°C for 15 minutes. A glass sheet was dip coated with the fluid at a lifting rate of 50 mm/min using a dip coating device, heated and dried at 150°C for 10 minutes to obtain a colorless, transparent coating film with a thickness of 3.0 μm. The coated glass sheet was placed in a refrigerator (about 0°C) for 5 minutes and then left at 25°C and 81% RH, with no fogging observed on the coated surface.A coating fluid was prepared by adding methanol and a 10% aqueous solution of polyvinyl alcohol (average polymerization degree: 2,000; saponification degree: about 82 mol%) to a 25% aqueous solution of polyacrylic acid (average molecular weight: 150,000), stirring the resulting mixture at ordinary temperature (25°C) for 10 minutes. Then, a solution of γ-glycidoxypropyltrimethoxysilane, a solution of a hydrolysate of aluminum isopropoxide (obtained by hydrolyzing aluminum isopropoxide using an acid catalyst in ethanol; 5% by weight in terms of Al2O3), and a 0.47% methanol solution of hydrosilicofluoric acid were added. The resulting mixture was stirred at ordinary temperature (25°C) for 15 minutes.Prepare a $10\\\\%$ methanol solution of $^{2,2^{\\prime},4,4^{\\prime}}$ -tetrahydroxybenzophenone and a $10\\\\%$ methanol solution of bis-[N-formyl-(2,2,6,6-tetramethyl-4- piperidyl)imino]hexamethylene. Add both solutions to a coating fluid prepared in accordance with the formulation shown in Table 3. Stir the mixture at ordinary temperature $(25^{\\\\circ}\\\\mathrm{C})$ for 15 minutes to obtain a yellow coating fluid. Apply the coating fluid to a glass sheet and dry as specified. The thickness of the coating film should be ${3.0\\\\ \\\\mu\\\\mathrm{m}}$. Expose the coated glass sheet to ultraviolet light $(250\\\\ \\\\mathrm{nm}, 4\\\\ \\\\mathrm{kW})$ for 20 hours from a distance of about 24 cm. Test the coated surface for anti-fogging properties after exposure.A composition is obtained by a polycondensation reaction of a hydrolysate of an inorganic alkoxide in the presence of a polyacrylic, polyvinyl alcohol, and either hydrosilicofluoric acid or a benzophenone compound. The resulting composition should include functional groups selected from hydrogen, hydroxyl, sulfonic acid, carboxyl, acyl, ester, ether, hydrocarbon groups, alkoxyl groups having 1 to 6 carbon atoms, amino, hydroxyalkyl, and hydroxyalkoxyl groups, ensuring at least one group is a hydroxyl or sulfonic acid group."
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