JP2004067947A - Coating liquid for forming photocatalytic layer and photocatalyst carrying structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating liquid for forming a photocatalytic layer having excellent weather resistance in spite of a single layer coating. <P>SOLUTION: This coating liquid for forming the photocatalytic layer comprises (A) an acrylic silicone resin or an epoxy silicone resin, (B) a silicon compound having 3-10 of a mean degree of polymerization and obtained by partial hydrolysis of one or more tetraalkoxysilane and (C) a titania sol dispersed in an organic solvent. <P>COPYRIGHT: (C)2004,JPO

Description

【００３２】
防汚性試験（サラダオイル分解試験）
各試料の表面にサラダオイルを０．１ｇ／ｃｍ^２の割合で塗布した後、１５Ｗの紫外線光源（東芝製、ブラックライトブルー（ＢＬＢ）蛍光灯）を用いて、２ｍＷ／ｃｍ^２の紫外線強度で紫外線を照射し残存しているサラダオイル量を測定してサラダオイル分解率を求めた。その経時変化を図１に示す。
【００３３】
親水性試験
各試料の表面層をエタノールで洗浄後、６０℃で８０分乾燥し、親水性測定の試料とした。試料に１５Ｗの紫外線光源（東芝製、ブラックライトブルー（ＢＬＢ）蛍光灯）を用いて、１ｍＷ／ｃｍ^２の紫外線強度で紫外線を照射し、その試料上に、マイクロシリンジから試料表面に水滴を滴下した後、８０秒後に、接触角測定器（エルマ（株）製、３６０Ｓ型）を用いて試料表面の接触角を測定した。その経時変化を図２に示す。
【００３４】
サンシャインカーボンアーク式促進耐候性試験
また、得られた試料Ａ、Ｂをサンシャインカーボンアークウェザーメーター（スガ試験機（株）製、ＷＥＬ−ＳＵＮ−ＨＣＨ型）を使用して、ＪＩＳ−Ｋ５４００に規定される促進耐候性試験を行ったところ、５００時間においても、同様の、親水性、防汚性、密着性、ハードコート性、透明性を示した。
【００３５】
【発明の効果】
本発明によれば厚膜化、低温硬化が可能で、高透明、親水性、耐候性である光触媒担持構造体を得ることができる。
【図面の簡単な説明】
【図１】実施例１の防汚性試験の結果を示す図である。
【図２】実施例１の親水性試験の結果を示す図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a coating solution for forming a photocatalyst layer for forming a photocatalyst layer on a carrier and a photocatalyst-carrying structure.
[0002]
[Prior art]
BACKGROUND ART Conventionally, a photocatalyst supporting structure in which a photocatalyst layer in which a substance having photocatalytic activity such as titanium dioxide is supported on a carrier such as a plastics plate, a glass plate, or a ceramics plate has been known.
[0003]
[Problems to be solved by the invention]
However, a single-layer photocatalyst-carrying structure without a protective intermediate layer on the carrier was not necessarily sufficient in weather resistance. An object of the present invention is to provide a coating solution for forming a photocatalyst layer that exhibits excellent weather resistance while being a single layer coat.
[0004]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above problems, and as a result, have found that the above problems can be solved by using a photocatalyst layer forming coating solution having a specific composition, and have completed the present invention. .
[0005]
That is, the present invention
(1) (A) an acrylic silicone resin or an epoxy silicone resin, (B) a silicon compound which is one or more partial hydrolysis products of tetraalkoxysilane and has an average degree of polymerization of 3 to 10, and ( C) a coating solution for forming a photocatalyst layer comprising a titania sol dispersed in an organic solvent;
(2) The coating solution for forming a photocatalyst layer according to the above (1) or (2), further comprising a surfactant, and (3) the coating solution according to any one of the above (1) to (2). A photocatalyst-carrying structure, which is produced by applying a coating solution for forming a photocatalyst layer to a substrate and then drying.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described in more detail.
[0007]
The acrylic silicone resin of the component (A) is a silicone-modified acrylic resin, and the epoxy silicone resin refers to a silicon-modified epoxy resin. As a method for introducing (modifying) silicon into an acrylic resin or an epoxy resin, a method based on a transesterification reaction, a method based on a graft reaction using a silicon macromer or a reactive silicon monomer, a method based on a hydrosilylation reaction, and a block copolymerization method are used. There are methods. In the present invention, any method can be used.
[0008]
Examples of the acrylic resin monomer include acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methoxyethyl acrylate, butoxyethyl acrylate, and phenyl acrylate Methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, methoxymethyl ethacrylate, methacrylsan ethoxymethyl, phenyl methacrylate, lauryl methacrylate, and acrylic acid-2- (N, N-dimethyl) Amino) ethyl, 2- (N, N-dimethylamino) ethyl methacrylate, 2- (N, N-dibenzylamino) ethyl methacrylate, 2- (N, N-diethylamino) propyl acrylate, etc. Acrylic acid or Methac Substituted amino alcohol esters of lactic acid, unsaturated carboxylic acid amides such as acrylamide and methacrylamide, ethylene glycol diacrylate, propylene glycol eye acrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate And glycol methacrylates such as dipropylene glycol diacrylate, ethylene glycol acrylate and diethylene glycol dimethacrylate.
[0009]
The epoxy resin is a thermosetting resin having an epoxy group. Usually, after obtaining a prepolymer having an epoxy group, a curing agent is added and a polymer having a three-dimensional network structure is obtained by a crosslinking reaction.
[0010]
As such a prepolymer, for example, a phenolic glycidyl obtained from a compound having an epoxy group such as epichlorohydrin and a phenol derivative such as bisphenol A, bisphenol F, tetrabromobisphenol A, tetraphenylolethane, phenol novolak, or o-cresol novolak Ether type epoxy resin, a compound having an epoxy group such as epichlorohydrin, and an alcohol-based glycidyl ether type epoxy resin obtained from polyols such as polypropylene glycol and hydrogenated bisphenol A, a compound having an epoxy group such as epichlorohydrin, and hexahydroanhydride phthalate Glycidyl ester type epoxy resins obtained from carboxylic acids such as acids and dimer acids, and compounds having an epoxy group such as epichlorohydrin , Diaminodiphenylmethane, isocyanuric acid, glycidyl amine type epoxy resins obtained from compounds of hydantoin and the like, a compound having an epoxy group, mixed epoxy resins derived from p- aminophenol and p- oxybenzoate, and the like.
[0011]
Examples of the tetraalkoxysilane of the silicon compound, which is one or more partial hydrolysis products of the tetraalkoxysilane (B) and has an average degree of polymerization of 3 to 10, include tetramethoxysilane and tetramethoxysilane. Ethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, or the like can be used. Among them, in the present invention, the use of tetramethoxysilane and tetraethoxysilane is particularly preferred from the viewpoints of availability and handling.
[0012]
The partial hydrolysis product of tetraalkoxysilane can be obtained, for example, by dissolving a predetermined amount of the tetraalkoxysilane in water or an organic solvent such as water, methanol, ethanol, or ethyl acetate, and then heating or adding a predetermined amount of an acid or base. And partially hydrolyzing it. Usually, the degree of polymerization is preferably 3 to 10, and the residual amount of the unreacted tetraalkoxysilane monomer is preferably 5% by weight or less, more preferably 1% by weight or less of the whole component (B).
[0013]
The organic solvent-dispersed titania sol of the component (C) is a sol in which titanium oxide is dispersed in an organic solvent insoluble in water and having a boiling point of 50 to 200 ° C. Examples of the organic solvent include aromatic hydrocarbons, ethers, ketones, alcohols, halogenated hydrocarbons and the like. Specifically, for example, benzene, toluene, xylene, tetrahydrofuran, methyl isobutyl ketone , Butanol, pentanol, carbon tetrachloride, chlorobenzene, chloroform and the like are preferred. The method for preparing the organic solvent-dispersed titania sol is not particularly limited. For example, a hydrolyzed titania sol is disclosed in JP-A-58-29863, such as sodium dotesylbenzenesulfonate and sodium dioctylsulfosuccinate. A method of preparing a sol by dispersing and transferring it in an organic solvent insoluble in water with an anionic surfactant as described above, a method of preparing a sol by hydrolysis of a titanium alkoxide having a long side chain, and the like are preferable.
[0014]
The photocatalyst-forming coating solution contains at least the components (A) to (C) and is used after being dissolved or suspended in an appropriate solvent. Such solvents include, for example, alcohols such as methanol, ethanol, isopropanol, butanol, ethyl acetate, acetates such as butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, ketones such as cyclohexanone, pentane, hexane, Use of aliphatic hydrocarbons such as heptane, cycloaliphatic hydrocarbons such as cyclohexane and methylcyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, and a mixture of two or more of these or water with these. Can be.
[0015]
In the coating solution for forming a photocatalyst of the present invention, the content of each component is usually 50 to 90% by weight with respect to the solid content in the coating solution for forming a photocatalyst, with the acrylic silicone resin or the epoxy silicone resin as the component (A) as a solid content. %, A silicon compound having one or more partial hydrolysis products of the tetraalkoxysilane of the component (B) and having an average degree of polymerization of 3 to 10 is used as a solid content in terms of silicon dioxide, for forming a photocatalyst. The organic solvent-dispersed titania sol of the component (C) is 5 to 45% by weight based on the solid content in the coating solution for forming a photocatalyst, based on the solid content in the coating solution. %. These solids are usually contained in the coating solution for forming a photocatalyst in an amount of 0.1 to 40% by weight.
[0016]
The photocatalyst-forming coating solution may contain a surfactant. Specifically, hydrocarbons such as NIKKOLBL, BC, BO, and BB series manufactured by Nikko Chemicals Co., Ltd .; ZONYL FSN and FSO manufactured by DuPont; Surflon S-141 and 145 manufactured by Asahi Glass Co., Ltd .; Non-ionic interfaces of fluorine or silicone such as MegaFac F-141 and 144 manufactured by Chemical Industry Co., Ltd., and Fagents F-200 and F251 manufactured by Neos Co., Ltd., and Unidyne DS-401 and 402 manufactured by Daikin Industries, Ltd. Examples of the surfactant include a cationic surfactant, an anionic surfactant, and an amphoteric surfactant. The addition amount is 0.005% by weight to 10% by weight, preferably 0.01% by weight to 5% by weight, based on the coating solution for forming a catalyst. In addition, other commonly used components such as a stabilizer may be contained.
[0017]
The method for supporting the photocatalyst is not particularly limited. For example, an organic solvent solution, an organic solvent suspension, or the like of the coating solution for forming a photocatalyst is printed on the carrier surface by a printing method, a sheet forming method, a spraying method, or a dip method. A method of coating with a coating method, a spin coating method or the like and drying the coating can be used. Although the drying temperature varies depending on the type of the solvent and the resin, a temperature of 150 ° C. or lower is preferable. The thickness of the photocatalyst layer is usually 0.1 to 5 μm.
[0018]
Before forming the photocatalyst layer, the carrier may be subjected to an easy adhesion treatment. Examples of such an easy adhesion treatment include a method of subjecting the surface of the intermediate layer to a corona discharge treatment or a UV-ozone treatment.
[0019]
The carrier used in the photocatalyst structure of the present invention is not particularly limited in its material, shape, etc., as long as it can support the photocatalyst layer. The shape of the carrier is not particularly limited as long as the photocatalyst can be supported, and examples thereof include a film, a tube, a fiber, a net, a plate, and a curved plate. More specifically, for example, polyolefin resins such as polyethylene and polypropylene, acrylic resins such as polymethyl methacrylate, polymethyl acrylate and polyethyl methacrylate, polyvinyl chloride, polystyrene, acrylonitrile-butadiene-styrene copolymer ( (ABS resin), thermoplastic resin such as polycarbonate, phenol resin, urea resin, unsaturated polyester, polyurethane, epoxy resin, melamine resin, thermosetting resin such as diallyl phthalate resin, etc., and synthesis of polyfluoroethylene, silicon resin, etc. Resin films and plates, various types of glass, ceramics, earthenware, ceramics such as enamel, gypsum, gypsum slag, calcium silicate, lightweight foamed concrete, hollow extruded cement, pulp cement, asbestos cement Board, wood chip cement Plate, glass fiber reinforced cement plate, iron plate, aluminum plate, aluminum alloy plate, galvanized steel plate, copper plate, copper alloy plate, metal plate such as stainless steel plate, wood veneer, wood plywood, particle board, MDF (medium density fiber Board), kraft paper, coated paper, titanium paper, linter paper, paperboard, gypsum board paper, woodfree paper, tissue paper, paraffin paper, glassine paper, art paper, parchment paper and other paper, wool, silk, etc. Consisting of natural fibers such as hemp, regenerated fibers such as rayon and acetate, synthetic fibers such as nylon, acrylic, polyamide, polyester, polyacrylonitrile, polyvinyl chloride and polyvinylidene chloride, and heat-resistant fibers such as aramid alone or blended. Composite of fiber glass fiber such as woven fabric, non-woven fabric and knitted fabric, asbestos, potassium titanate fiber, silica fiber, carbon fiber, alumina fiber, etc. So-called FRP board obtained by impregnating and curing resin such as phenolic resin, urea resin, unsaturated polyester, polyurethane, epoxy resin, and melamine resin into glass fiber, nonwoven fabric, cloth, paper, and other various fiber base materials. And the like. In addition, a composite base material obtained by laminating two or more of the above-described various materials by a known method such as an adhesive or heat fusion can also be used.
[0020]
Examples of the article having at least a part of the photocatalyst-supporting structure of the present invention include interior and exterior materials of buildings such as wallpaper, wall materials, window glasses, sashes, window frames, blinds, curtains, carpets, and showcases. And other interior products, eyeglasses, glass lenses, windshields, door mirrors, mirrors and other glass products, lighting equipment, lighting, black lights, televisions, refrigerators, audio equipment, computers, personal computers, printers, facsimile and other electrical equipment , Tents, umbrellas, tablecloths and other daily necessities, furniture such as chests, bookcases, desks, tables, etc., interior and exterior materials of vehicles such as cars, trains, airplanes, ships, etc. Examples include agricultural and horticultural sheets and food packaging materials.
[0021]
The plastic film provided with the photocatalyst structure of the present invention is a film in which an acrylic or silicone adhesive is applied to the back surface of a carrier that does not carry a photocatalyst by utilizing its antifouling, antibacterial, and deodorizing functions. Thereby, it can be stuck on the inner surface of a bulkhead iron plate, window glass of automobiles and various transportation equipment, frozen / refrigerated showcases, greenhouses, and the like.
[0022]
Then, it becomes possible to obtain a film having high transparency which is effective for decomposing a trace amount of organic substance in the internal space, preventing contamination of the glass surface and preventing scattering at the time of breakage.
[0023]
Examples of such a highly transparent carrier include polyethylene terephthalate, polycarbonate, polyacrylate, polymethacrylate, polyethylene, polypropylene, polyamide, polyimide, polystyrene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, and ethylene fluoride. -Transparency in which the linear transmittance of light having a wavelength of 550 nm is 50% or more when formed into a film such as a propylene copolymer, a fluorinated ethylene-ethylene copolymer, or an ethylene-vinyl acetate copolymer. High synthetic resin films or sheets can be mentioned.
[0024]
【Example】
Next, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples, and within the scope not departing from the gist of the present invention, the material and shape of the carrier, the content of the coating solution for forming the photocatalytic layer, the mixing ratio, the thickness of each layer, etc. Can be changed.
[0025]
Example 1
(1) Preparation of Coating Solution Ethanol-sec-butanol containing 7.5 g of acrylic silicone resin (containing 2 to 3% of silicon content in terms of SiO2) in terms of solid content, and 2.5 g of methylsilicate oligomer in terms of SiO2. To 100 g of an ethyl acetate mixed solution, 0.05 g of a surfactant and 20 g of an organic solvent-dispersed titania sol (a mixed solution of TKS-251, an isopropanol-toluene having a solid content concentration of 20% by weight as titanium oxide, manufactured by Teica) at room temperature and with stirring. Solution A was prepared by dropwise addition.
A solution B was prepared in the same manner except that 10 g of the same organic solvent-dispersed titania sol was used.
[0026]
(2) Preparation of Photocatalyst Supporting Structure Soda-lime glass was used for the substrate. A glass substrate is dip-coated on the solutions A and B prepared as described above at a pulling rate of 10 cm / min, and dried at 120 ° C. for 30 minutes, and the photocatalyst supporting structures A and B each having a photocatalyst layer on the glass substrate. Was prepared.
[0027]
(3) Evaluation of Photocatalyst-Supporting Structure The following evaluation tests were performed on the photocatalyst-supporting structures A and B prepared as described above.
[0028]
Total light transmittance and linear transmittance The total light transmittance (T), the linear transmittance (P), and the haze (Hz) of the sample at 550 nm were determined with reference to the glass substrate before forming the photocatalytic layer. It was measured with a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH-300A type).
[0029]
Hard coat property (surface pencil hardness)
JIS K 5400-1900 8.4 Pencil scratch value 8.4.1 Measured with a weight load of 1 kg in accordance with the method described in the tester method, and (5) (b) When evaluating by abrasion of the coating film The pencil hardness was evaluated according to the following.
[0030]
Adhesion (finger rub test)
The membrane surface was rubbed with the abdomen of the thumb, and the membrane was visually observed for peeling.
Table 1 summarizes the above results.
[0031]
[Table 1]

[0032]
Antifouling test (salad oil decomposition test)
After applying salad oil to the surface of each sample at a rate of 0.1 g / cm ² , using a 15 W ultraviolet light source (manufactured by Toshiba, black light blue (BLB) fluorescent lamp) at an ultraviolet intensity of ² mW / cm ² The remaining salad oil was measured by irradiating ultraviolet rays to determine the salad oil decomposition rate. The change over time is shown in FIG.
[0033]
Hydrophilicity test The surface layer of each sample was washed with ethanol and dried at 60 ° C for 80 minutes to obtain a sample for measuring hydrophilicity. The sample is irradiated with ultraviolet light at an intensity of 1 mW / cm ² using a 15 W ultraviolet light source (manufactured by Toshiba, Black Light Blue (BLB) fluorescent lamp), and a water drop is dropped on the sample surface from the micro syringe on the sample. After 80 seconds, the contact angle of the sample surface was measured using a contact angle measuring device (360S type, manufactured by Elma Corporation). The change over time is shown in FIG.
[0034]
Sunshine carbon arc type accelerated weather resistance test Further , the obtained samples A and B were subjected to JIS- using a sunshine carbon arc weather meter (manufactured by Suga Test Instruments Co., Ltd., WEL-SUN-HCH type). When an accelerated weather resistance test specified in K5400 was performed, the same hydrophilicity, antifouling property, adhesion, hard coat property, and transparency were exhibited even after 500 hours.
[0035]
【The invention's effect】
According to the present invention, it is possible to obtain a photocatalyst-supporting structure that can be made thicker and cured at a low temperature, and is highly transparent, hydrophilic, and weather-resistant.
[Brief description of the drawings]
FIG. 1 is a view showing the results of an antifouling test of Example 1.
FIG. 2 is a view showing the results of a hydrophilicity test of Example 1.

Claims (3)

(A) an acrylic silicone resin or an epoxy silicone resin, (B) one or more partial hydrolysis products of tetraalkoxysilane, a silicon compound having an average degree of polymerization of 3 to 10, and (C) an organic compound. A coating solution for forming a photocatalyst layer, comprising a solvent-dispersed titania sol. The coating solution for forming a photocatalyst layer according to claim 1, further comprising a surfactant. A photocatalyst-carrying structure, which is prepared by applying the coating solution for forming a photocatalyst layer according to any one of claims 1 to 2 to a substrate, followed by drying.

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