Sheet coated with silicone elastomer and manufacture thereof

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a silicone elastomer coated sheet and a method for producing the same. More specifically, the present invention relates to a silicone elastomer-coated sheet-like material having excellent antifouling properties, which is hard to adhere to stains and can be easily decomposed and removed even if stains are attached, and a method for producing the same.

【0002】

[Conventional technology]

Sheets coated with silicone elastomer, such as silicone elastomer-coated cloth, are lightweight and have excellent weather resistance and bending resistance. Therefore, materials for air film structures, exterior materials for buildings such as gymnasiums and warehouses, and exterior materials for buildings such as warehouses and warehouses. It has been proposed to be used as a tent or a tarpaulin (see JP-A-59-29157). However, this type of silicone elastomer-coated cloth has a drawback that when it is continuously used for a long period of time for the above-mentioned applications, soot and the like gradually adhere to it and darken it. Moreover, there is a fatal defect that dirt adhering to the silicone elastomer coated cloth is difficult to remove, and in particular, a large area coating cloth used in gymnasiums has a problem that it takes a lot of labor to wash off the dirt. .. In addition, since silicone elastomer-coated cloth is extremely flexible and highly elastic, it has been proposed to use it as a diaper cover or bandage made of knitted fabric (see Japanese Patent Publication No. 1-26336). However, when used for these purposes, there is a drawback that chlorine sterilization or steam sterilization with steam must be performed from time to time for sterilization.

【0003】

[Problems to be Solved by the Invention]

As a result of diligent studies to solve the above problems, the present inventors have found that the above problems can be solved by fixing titanium oxide powder having photocatalytic activity to the surface layer portion of the silicone elastomer coating, and reached the present invention. did. That is, an object of the present invention is to provide a silicone elastomer-coated sheet-like material having excellent antifouling properties, which is difficult for stains to adhere to, and which can be easily decomposed and removed even if stains are attached, and a method for producing the same. is there.

【0004】

[Means and Actions for Solving Problems]

The present invention is a sheet-like material coated with a silicone elastomer, wherein a titanium oxide powder having a photocatalytic ability is adhered to the surface layer portion of the silicone elastomer, and a silicone elastomer-coated sheet-like material and a sheet-like material. The present invention relates to a method for producing a silicone elastomer-coated sheet-like material, which comprises applying a silicone elastomer composition to a product, then supporting a titanium oxide powder having a photocatalytic ability on the surface thereof, and then curing the silicone elastomer composition. ..

【0005】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail. The sheet-like material of the present invention is coated with a silicone elastomer, and is characterized in that titanium oxide powder having a photocatalytic ability is adhered to the surface layer portion thereof. This is because if the titanium oxide powder is not fixed to the surface layer and is uniformly dispersed in the silicone elastomer, it will be covered with the silicone elastomer, so that it will be difficult to be excited by light irradiation, and effects such as oxidative decomposition action will be obtained. This is because it drops significantly. The thickness of the silicone elastomer coating layer is preferably 10 to 500 μm, more preferably 50 to 200 μm. The surface layer portion refers to a portion from the surface to a depth of about 3 μm. Further, the sticking means a state of being firmly stuck, and the present invention intends a state in which the titanium oxide powder having a photocatalytic ability is firmly held in the silicone elastomer and does not easily fall off. The amount of sticking is 2 to 20 g / m²Is preferable, especially 3 to 5 g / m.²Is more preferable. The sheet-like material of the present invention may have a silicone elastomer coating layer supporting titanium oxide powder having such photocatalytic activity on only one side or on both sides. That is, a double-sided deodorant sheet can be prepared by coating both sides with a silicone elastomer composition and supporting titanium oxide powder having photocatalytic activity, and the silicone elastomer coating layer is provided only on the surface of the curtain material that is in contact with the window side. It can also be used as an antifouling curtain.

【0006】

Sheets used in the present invention include papers including synthetic paper; various films such as nylon, polyester, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polypropylene, polyvinyl alcohol, polyvinyl chloride, and polystyrene; fabrics. Examples include knitted fabrics made of natural fibers such as cotton, wool, silk and linen, semi-synthetic fibers such as acetate, Bemberg and Polynosic, and synthetic fibers such as nylon, polyester, acrylic, modacryl, polypropylene, polyethylene and vinylon. Examples of knitted fabrics or woven fabrics made of inorganic fibers such as non-woven fabrics, glass fibers, rock wool, and asbestos. The fabrics may be dyed with various dyes in advance. The sheet shape is suitable for continuous production, that is, the silicone elastomer composition can be continuously coated with a knife coater or the like.

【0007】

Examples of the silicone elastomer used in the present invention include an addition reaction curable silicone elastomer composition, a condensation reaction curable silicone elastomer composition, and a cured product of a radical (peroxide crosslinked) reaction curable silicone elastomer composition. Among these, the addition reaction curable silicone elastomer composition which can be cured at high speed even under low temperature conditions and can be coated in a wide range of concentrations, that is, the silicone elastomer composition which can be used either 100% or diluted with toluene or the like is the most. preferable.

【0008】

The addition reaction curable silicone elastomer composition refers to a composition in which functional groups in two types of organopolysiloxanes are bonded and crosslinked by an addition reaction to form an elastomer. A typical example thereof is a silicone elastomer composition composed of an organopolysiloxane containing an aliphatic unsaturated group such as a vinyl group or a hexenyl group, an organohydrogenpolysiloxane, and a platinum group compound-based catalyst. Examples of the aliphatic unsaturated group-containing organopolysiloxane include both-terminal vinyldimethylsiloxy group-blocking dimethylpolysiloxane, both-terminal vinyldimethylsiloxy group-blocking dimethylsiloxane / methylvinylsiloxane copolymer, and both-terminal vinylmethylphenylsiloxy group-blocking dimethylsiloxane. -Methylphenylsiloxane copolymer is exemplified. Organohydrogenpolysiloxane includes both-terminal trimethylsiloxy group-blocked methylhydrogenpolysiloxane, both-terminal trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, and both-terminal dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydro. Examples thereof include gensiloxane copolymer and methylhydrogencyclopolysiloxane. Examples of the platinum group compound catalyst include fine particle platinum, chloroplatinic acid, platinum and olefin complex, platinum and vinyl siloxane complex, platinum and diketone complex, palladium compound catalyst, and rhodium compound catalyst. Among these, a platinum compound-based catalyst is preferable from the viewpoint of catalytic activity. This addition reaction curable silicone elastomer composition is usually heated and cured from the viewpoint of curability and productivity. In addition, the addition reaction curable silicone elastomer composition is composed of an organopolysiloxane containing an aliphatic unsaturated group such as a vinyl group and an organopolysiloxane containing a mercaptoalkyl group, and is subjected to ultraviolet irradiation or electron beam irradiation. Examples include a composition that cures.

【0009】

The condensation reaction-curable silicone elastomer composition is formed into an elastomer by bonding functional groups in two types of organopolysiloxanes or functional groups in an organopolysiloxane and a silicon compound such as silica or silane by a condensation reaction to crosslink them. Refers to the composition to be used. Examples of the condensation reaction-curable silicone elastomer composition include dehydrogen condensation type, dehydration condensation type, deacetic acid condensation type, deoxime condensation type, dealcohol condensation type, deamide condensation type, dehydroxylamine condensation type, and deoxidation. Examples thereof include an acetone condensation type composition.

【0010】

A typical example of the dehydrogenation condensation reaction curing type silicone elastomer composition is a composition composed of a condensation reaction catalyst such as a diorganopolysiloxane having both ends silanol groups sealed, an organohydrogenpolysiloxane, and a heavy metal salt of an organic acid. As the diorganopolysiloxane with both terminal silanol groups, both terminal silanol group blocking dimethylpolysiloxane, both terminal silanol group blocking dimethylsiloxane / methylphenylsiloxane copolymer, and both terminal silanol group blocking methyl (3,3,3-tri) Fluoropropyl) polysiloxane is exemplified. Since this diorganopolysiloxane has an effect of suppressing the condensation reaction, a part of the terminal silanol group may be alkoxylated. Examples of the organohydrogenpolysiloxane as a cross-linking agent include dimethylhydrogensiloxy group-blocking dimethylsiloxane / methylhydrogensiloxane copolymer at both ends, trimethylsiloxy group-blocking methylhydrogenpolysiloxane at both ends, and methylhydrogencyclopolysiloxane. Illustrated. Examples of the condensation reaction catalyst include dibutyltin dilaurate, dibutyltin diacetate, tin octate, dibutyltin dioctate, tin laurate, ferric stanooctate, lead octate, lead laurate, and zinc octate.

【0011】

The dehydrogenation condensation reaction curing type silicone elastomer composition needs to be cured by heating from the viewpoint of curability and productivity, but dehydration condensation type, deacetic acid condensation type, deoxime condensation type, dealcohol condensation type, The deamide condensation type, dehydroxylamine condensation type, and deacetone condensation type silicone elastomer compositions can be cured at room temperature in the presence of moisture to become an elastomer. Therefore, when the sheet-like product of the present invention is produced using such a moisture-curable silicone elastomer composition, the productivity is further improved by heating while supplying an appropriate amount of moisture for continuous production. Is possible. Among the moisture-curable silicone elastomer compositions, silicone water-based elastomers, which can form an elastomer by removing water, are particularly useful for fabrics. The silicone water-based elastomer usually includes (a) a substantially linear organopolysiloxane having at least two silanol groups in one molecule, (b) colloidal silica, alkali metal silicate, and hydrolysis. An aqueous organopolysiloxane emulsion composition consisting of a cross-linking agent selected from the group consisting of possible silanes and partially hydrolyzed condensates thereof, (c) a curing catalyst, (d) an elastomer and (e) water is used.

【0012】

Here, the organopolysiloxane of the component (a) is a polymer that is crosslinked by the action of the component (b) to become a rubber-like elastic body, and has at least two silanol groups in one molecule. The position of this silanol group is not particularly limited, but it is preferably present at both ends. As the organic group bonded to a silicon atom other than the silanol group, an unsubstituted or substituted monovalent hydrocarbon group is preferable, an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group; a vinyl group, an allyl group or the like. Alkenyl group; aryl group such as phenyl group; aralkyl group such as benzyl group; alkaline group such as styryl group and trill group; cycloalkyl group such as cyclohexyl group and cyclopentyl group and some or all of hydrogen atoms of these groups Groups substituted with halogen atoms such as fluorine, chlorine and bromine, for example, 3-chloropropyl group, 3,3,3-trifluoropropyl group and the like can be mentioned. Among these, a methyl group, a vinyl group, and a phenyl group are preferable, and a methyl group is more preferable, but they do not have to be all the same and may be a combination of different monovalent hydrocarbon groups. Further, substantially linear means that it may be linear having a partially branched chain. The molecular weight of this organopolysiloxane is not particularly limited, but is preferably 5,000 or more. This is because reasonable tensile strength and elongation can be obtained when the molecular weight is 3,000 or more, but the most preferable tensile strength and elongation can be obtained only when the molecular weight is 5,000 or more. However, it is preferably 1,000,000 or less from the viewpoint of the possibility of emulsification into an emulsion. Specific examples of such an organopolysiloxane include dimethylpolysiloxane, methylphenylpolysiloxane, dimethylsiloxane / methylphenylsiloxane copolymer, methylvinylpolysiloxane, in which both ends of the molecular chain are sealed with silanol. Examples thereof include a dimethylsiloxane / methylvinylsiloxane copolymer. Such an organopolysiloxane can be synthesized, for example, by a method of hydrolyzing and condensing a cyclic or branched organopolysiloxane, or a method of hydrolyzing one or more diorganodihalogenosilanes.

【0013】

The cross-linking agent for the component (b) acts as a cross-linking component for the component (a), and examples thereof include colloidal silica, alkali metal silicate, hydrolyzable silane, or a partially hydrolyzed condensate thereof. Examples of the colloidal silica include fumes-like colloidal silica, precipitated colloidal silica, and colloidal silica having a particle size of 0.0001 to 0.1 μm stabilized with sodium, ammonia, or aluminum ions. The blending amount of the colloidal silica is preferably 1 to 150 parts by weight, more preferably 1 to 70 parts by weight, based on 100 parts by weight of the organopolysiloxane of the component (a). Examples of the alkali metal silicate include lithium silicate, sodium silicate, potassium silicate, and rubidium silicate. The blending amount of the alkali metal silicate is preferably 0.3 to 30 parts by weight, more preferably 0.3 to 20 parts by weight, based on 100 parts by weight of the organopolysiloxane of the component (a). As the hydrolyzable silane, a silane having at least three hydrolyzable groups bonded to a silicon atom in one molecule is used. This is because an elastomer cannot be obtained if the number is less than three. Examples of the hydrolyzable group include an alkoxy group such as a methoxy group, an ethoxy group and a butoxy group; an acyloxy group such as an acetoxy group; a substituted or unsubstituted acetamide group such as an acetamide group and an N-methylacetamide group; a propenoxy. Examples thereof include an alkenyloxy group such as a group; a substituted amino group such as an N, N-diethylamino group; and a ketooxym group such as a methylethylketooxym group. Specifically, methyltrimethoxysilane, vinyltrimethoxysilane, normalpropyl orthosilicate, ethylpolysilicate, propylpolysilicate, methyltri (propanoxy) silane, Methyltri (methylethylketooxime) silane is exemplified. Two or more such silanes can be mixed and used. The blending amount of the hydrolyzable silane or its partially hydrolyzed condensate is preferably 1 to 150 parts by weight with respect to 100 parts by weight of the organopolysiloxane of the component (a).

【0014】

The curing catalyst of the component (c) is a component that promotes the condensation reaction between the organopolysiloxane of the component (a) and the cross-linking agent of the component (b). , Dibutyltin dioctate, tin laurate, ferric stanooctate, lead octenoate, lead laurate, zinc octate and other organic acid metal salts; tetrabutyl titanate, tetrapropyl titanate, dibutoxytitanium bis (ethylacetoacetate), etc. Titanic acid ester; n-hexylamine, amine compounds such as guanidine, or hydrochloric acids thereof. It is preferable that these curing catalysts are formed into an emulsion by a usual method using an emulsifier and water in advance. The amount of the curing catalyst added is preferably 0.01 to 1.5 parts by weight, more preferably 0.05 to 1 part by weight, based on 100 parts by weight of the organopolysiloxane of the component (a).

【0015】

The emulsifier of the component (d) is mainly a component that emulsifies the organopolysiloxane of the component (a), and examples thereof include anionic emulsifiers, nonionic emulsifiers, and cationic emulsifiers. Examples of anionic emulsifiers include higher fatty acid salts, higher alcohol sulfate esters, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkylhofsphonates, and polyethylene glycol sulfates. Examples of nonionic emulsifiers include polyoxyethylene alkylphenyl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyalkylene fatty acid esters, polyoxyethylene polyoxypropylenes, and fatty acid monoglycerides. Be done. Examples of the cationic emulsifier include aliphatic amine salts, quaternary ammonium salts, and alkylpyridinium salts. These emulsifiers may be used alone or in admixture of two or more. The blending amount of this emulsifier is preferably 2 to 30 parts by weight with respect to 100 parts by weight of the organopolysiloxane of the component (a).

【0016】

The amount of water in the component (e) is determined by emulsifying the organopolysiloxane of the component (a), the cross-linking agent of the component (b), and the curing catalyst of the component (c) by the action of the emulsifier of the component (d). The amount may be sufficient to prepare an aqueous emulsion, and is not particularly limited.

【0017】

This silicone water-based elastomer emulsion can be prepared by uniformly mixing the above components (a) to (e). For example, dimethylpolysiloxane having both terminal silanol groups is emulsified in water using an emulsifier such as a homomixer, homogenizer, or colloid mill in the presence of an emulsifier, and then a cross-linking agent such as colloidal silica or a curing catalyst is added. By emulsifying cyclic diorganopolysiloxane such as octamethylcyclotetrasiloxane into water using an emulsifier, and then adding a ring-opening polymerization catalyst and polymerizing under heating, both ends are silanol groups. An example is a method in which an emulsion of dimethylpolysiloxane sealed with is prepared, and a cross-linking agent such as colloidal silica or a curing catalyst is added thereto and mixed. Further, by preparing a base emulsion composed of the components (a) to (e) and then adjusting the pH to 9 to 12, an emulsion having extremely excellent storage stability can be obtained. As the pH adjuster, for example, amines such as dimethylamine and ethylenediamine; and hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide can be used. Among these, organic amines are preferable, and as organic amines other than the above, monoethanolamine, triethanolamine, morpholine, etc. 2-Amino-2-methyl-1-propanol is exemplified. After adjusting the pH in this way, it is preferable to ripen at a constant temperature for a certain period of time. The aging temperature is preferably a temperature at which the emulsion is not destroyed, that is, in the range of 10 to 60 ° C, and more preferably in the range of 15 to 50 ° C. The aging period is set according to the aging temperature, and is preferably 1 week or longer under a temperature condition of 25 ° C. and 4 days or longer under a temperature condition of 40 ° C. The organopolysiloxane emulsion thus obtained has excellent storage stability at room temperature, and can be easily cured at room temperature to form an elastomer by removing water. On the other hand, the pH of the base emulsion may be less than 9 if storage stability at room temperature is not required. In addition, components other than the above, such as fillers, thickeners, pigments, dyes, heat resistant agents, preservatives, and penetrating aids such as aqueous ammonia, can be appropriately added to and blended with the organopolysiloxane emulsion. In particular, when colloidal silica is not used as the cross-linking agent for the component (b) above, the consistency of the organopolysiloxane emulsion becomes poor and it becomes difficult to obtain a thick elastomer. Therefore, fine powdered quartz is used as a filler. , Calcium carbonate, magnesium oxide, zinc dioxide, titanium dioxide powder, carbon black and the like are preferably added and blended. Further, these fillers are preferably colloidal because the tensile strength and elongation of the elastomer produced by removing water increase when they are colloidal. Further, as the thickener, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, polyacrylic acid and the like can be used. A penetrating aid such as aqueous ammonia can be added and blended as appropriate. In particular, when colloidal silica is not used as the cross-linking agent for the component (b) above, the consistency of the organopolysiloxane emulsion becomes poor and it becomes difficult to obtain a thick elastomer. Therefore, fine powdered quartz is used as a filler. , Calcium carbonate, magnesium oxide, zinc dioxide, titanium dioxide powder, carbon black and the like are preferably added and blended. Further, these fillers are preferably colloidal because the tensile strength and elongation of the elastomer produced by removing water increase when they are colloidal. Further, as the thickener, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, polyacrylic acid and the like can be used. A penetrating aid such as aqueous ammonia can be added and blended as appropriate. In particular, when colloidal silica is not used as the cross-linking agent for the component (b) above, the consistency of the organopolysiloxane emulsion becomes poor and it becomes difficult to obtain a thick elastomer. Therefore, fine powdered quartz is used as a filler. , Calcium carbonate, magnesium oxide, zinc dioxide, titanium dioxide powder, carbon black and the like are preferably added and blended. Further, these fillers are preferably colloidal because the tensile strength and elongation of the elastomer produced by removing water increase when they are colloidal. Further, as the thickener, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, polyacrylic acid and the like can be used.

【0018】

In addition to this, as the moisture-curable silicone elastomer composition, the main component is the biorganopolysiloxane (preferably having a viscosity of 1,000 to 60,000 centimeters at 25 ° C) as described above. Deacetic acid condensation type silicone elastomer composition obtained by blending, for example, vinyltriacetoxysilane as a cross-linking agent, dibutyltin diacetate or dibutyltin dilaurate as a catalyst, and further adding reinforcing fillers such as aerodil and kneading uniformly. In this deacetic acid condensation type composition, a deoxime condensation type silicone elastomer composition obtained by substituting vinyl triacetoxysilane with vinyltrioxymsilane, and similarly, by substituting vinyltriacetoxysilane with tetraethoxysilane or the like. Examples thereof include a dealcohol condensation type silicone elastomer composition. The cross-linking agent used may be any as long as it can elastomerize the silanol group-blocking diorganopolysiloxane, and is not limited to the above-mentioned cross-linking system.

【0019】

Examples of the radical reaction-curable silicone elastomer composition include a composition composed of an organopolysiloxane, a reinforcing filler and an organic peroxide, and additional components include an increase filler, a heat resistant agent, a flame retardant, a pigment and an organic solvent. Etc. can be contained. Organopolysiloxane has both ends sealed with trimethylsiloxy group, dimethylvinylsiloxy group, methylphenylvinylsiloxy group or silanol group, and the main chain is dimethylpolysiloxane, dimethylsiloxane / methylphenylsiloxane copolymer, dimethylsiloxane. Examples thereof include raw rubber-like polymers such as methylvinylsiloxane copolymers, dimethylsiloxane / methylphenylsiloxane / methylvinylsiloxane copolymers, and methyl (3,3,3-trifluoropropyl) / methylvinylsiloxane copolymers. .. Humed silica is exemplified as the reinforcing filler. Organic peroxides include benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-. Examples include 2,5-di (t-butylperoxy) hexene. This radical reaction-curable silicone elastomer composition is usually heated and cured from the viewpoint of curability and productivity. In addition, as a radical reaction-curable silicone elastomer composition, an organopolysiloxane raw rubber and a reinforcing filler are used as main components, and an additional filler, a heat resistant agent, a flame retardant, a pigment, an organic solvent, etc. are contained as additional components. Examples thereof include a composition which is cured by β-ray or γ-ray irradiation, and a composition which is composed of a silicon atom-bonded alkenyl group-containing organopolysiloxane, a sensitizer and a reinforcing filler and is cured by ultraviolet irradiation.

【0020】

Such a silicone elastomer composition used in the present invention may be diluted with a solvent such as toluene, xylene, n-hexane, etc. at the time of use, and when emulsified with an emulsifier in advance, a diluent It is also possible to further add water as an emulsifier. Further, the light weather resistance of the sheet-like material of the present invention can be improved by adding an inorganic pigment or the like to the silicone elastomer composition for coloring, or by adding a chemical such as an ultraviolet absorber.

【0021】

The photocatalytic titanium oxide powder used in the present invention is a characteristic component of the present invention, and has a property of being excited by light irradiation to oxidatively decompose adhering organic stains and malodors. Such titanium oxide powder is not particularly limited as long as it is excited by light irradiation and exhibits a photocatalytic action, but usually has a very small particle size of 5 to 25 nm (measurement of particle size by X-ray). Specific surface area is 100-350m²A very large fine powder of / g is used. In addition to pure titanium oxide, the titanium oxide of the present invention includes those generally called hydrous titanium, metatitanic acid, and orthotitanium acid, and the crystal type thereof does not matter. The titanium oxide powder having such photocatalytic activity is, for example, a method of heating and hydrolyzing a titanium compound such as titanium chloride or titanium alkoxide, a method of adding an alkaline substance to the titanium compound as described above to neutralize it, or a method of neutralizing the titanium compound. It can be produced by a method of firing titanium oxide obtained by these methods. In order to further enhance the photocatalytic activity, the surface of the titanium oxide powder may be coated with a metal such as platinum, gold, silver, copper, rhodium, ruthenium, or a metal oxide. Further, the titanium oxide powder may be treated in advance with an adsorbent such as zeolite or silica gel using a binder or the like.

【0022】

In such a sheet-like material of the present invention, for example, the silicone elastomer composition is applied to a continuous sheet-like material, and then titanium oxide powder having a photocatalytic ability is adhered and supported on the surface of the continuous sheet-like material, and then the silicone elastomer is supported. It can be produced by curing the composition. At this time, the silicone elastomer composition can be uniformly applied by using a coater such as a knife coater, a gravure coater, a kiss roll coater, or a spray. After the sheet-like material is coated with the silicone elastomer composition in this way, the titanium oxide powder is sprayed onto the surface thereof by spraying or the like, or evenly sprayed in small amounts to adhere to the surface thereof. Since this titanium oxide powder is preferably supported on the surface of the silicone elastomer coating layer without being washed away by washing or wind and rain, it is adhered to the silicone elastomer composition, then subsided to some extent, and then heated. It is preferable to apply and cure. When a small amount of sheet-like material is coated with a moisture-curable silicone elastomer composition, it is cured only by leaving it at room temperature without heating. In particular, when the silicone elastomer composition is coated on the fabric to a thickness of 20 to 100 μm, the curing is easily completed. After curing, a method of continuously winding the obtained sheet-like material is preferable from the viewpoint of productivity.

【0023】

Since the titanium oxide powder having strong photocatalytic activity is supported on the surface layer of the sheet-like material of the present invention as described above, it has a strong oxidative decomposition action by irradiation with ultraviolet rays. Therefore, even if dirt such as soot adheres, it is quickly decomposed by ultraviolet irradiation and then washed away by wind and rain, so that there is an advantage that a clean surface can always be maintained without depositing dirt. In addition, even if mold or algae spores adhere to the surface of the sheet, it is oxidatively decomposed, and at the same time, dirt (fine organic dust, etc.) that is a nutrient source is naturally decomposed and washed away. It has the advantage that it does not reproduce. Therefore, the sheet-like material of the present invention is characterized by being excellent in antifouling property, antifungal property and anti-algae property. Therefore, the silicone elastomer-coated fabrics of the present invention are suitably used as a film material for dome-type baseball stadiums and tents. Furthermore, since pathogenic bacteria such as Staphylococcus aureus are easily oxidatively decomposed and detoxified by the titanium oxide powder, the silicone elastomer-coated fabrics of the present invention can also be applied to hospital bed fabrics and the like. Further, when the silicone elastomer-coated non-woven fabric sheet of the present invention is used as a shoe underlay or the like, Escherichia coli or the like adhering to the underlay during shoe removal is easily sterilized. Further, since the silicone elastomer-coated fabrics of the present invention are sterilized only by drying with sunlight, when used as a squeeze cover used in hospitals and maternity hospitals, sterilization treatments such as chlorine sterilization and steam sterilization after washing It has the advantage that the process can be omitted. Further, since the sheet-like material of the present invention has the titanium oxide powder fixed thereto, it has an advantage that the antifouling effect is maintained. Therefore, the silicone elastomer coating film of the present invention can maintain transparency for a long period of time, and is made of polyvinyl chloride, which causes dark stains to adhere to the film, which reduces the light transmittance and suppresses the growth of plants. Instead of a sheet, it can be used as a film for tunnel cultivation.

【0024】

[Example]

Hereinafter, the present invention will be described in detail with reference to Examples. In the examples, parts mean parts by weight, viscosity means measurements at 25 ° C, and% means percent by weight.

【0025】

[Example 1]

Gum-like double-ended dimethylvinylsiloxy group-blocking methylvinylsiloxane / dimethylsiloxane copolymer (vinyl group content%: 0.15%) 100 parts, reinforcing fumed silica [manufactured by Nippon Aerosil Co., Ltd .; trade name Aerosil 300] 25 parts , 5 parts of silicone-based plasticizer (silanol group-blocking dimethylpolysiloxane at both ends with a degree of polymerization of 10) was added, and the mixture was kneaded at 150 ° C. for 3 hours using a kneader mixer. After adding 2.5 parts of methylhydrogenpolysiloxane to 27.5 parts of the silicone elastomer base thus obtained and uniformly dissolving this in 70 parts of toluene (the viscosity of this toluene solution was 250,000 centipoise). Next, 1.0 part of a platinum-based catalyst was added to prepare a silicone elastomer composition. A tarpaulin base cloth (nylon 66 plain weave tarpaulin base cloth) cut to a size of 30 x 30 cm is placed on a glass plate, and an applicator is used on the surface of this base cloth to apply the above silicone elastomer composition to a thickness of 200 μm. I applied it to the glass. Immediately after application, titanium oxide powder with photocatalytic activity wrapped in 6 layers of gauze [manufactured by Ishihara Techno Co., Ltd .; trade name ST-01, X-ray particle size measurement 5 nm, specific surface area 300 m²Titanium oxide fine powder with strong photocatalytic activity of / g] was sprayed evenly by tapping lightly from a height of 30 cm (3 g / m).²). This was then quickly placed in an oven at 130 ° C. and heated for 3 minutes to cure the silicone elastomer composition to prepare a silicone elastomer coated base fabric. The surface of the silicone elastomer-coated base cloth thus obtained was uniformly coated with a 0.5% acetone solution of a pigment [manufactured by Mitsubishi Chemical Corporation; trade name Diaresin Blue P] using a simple spray gun to contaminate it. This was irradiated with ultraviolet rays using a fade meter for weather resistance lowness of the dyed product (irradiation time 1.0 hour, 2.5 hours, 5.0 hours), and the discoloration and fading after irradiation was judged by the gray scale for fading of JIS L 0804. .. The results are shown in Table 1. The discoloration and fading of the silicone elastomer-coated base fabric of the present invention was remarkably large, and the oxidative decomposition effect of the titanium oxide powder having photocatalytic activity was remarkable.

【0026】

[Comparative example 1]

In Example 1, a silicone elastomer-coated base cloth was prepared in the same manner as in Example 1 except that the titanium oxide powder having a photocatalytic ability was not sprayed. The discoloration and fading of the obtained base cloth after irradiation with ultraviolet rays was measured in the same manner as in Example 1. The results are shown in Table 1.

【0027】

[Comparative Example 2]

To 100 parts of the silicone elastomer composition prepared in Example 1, 1.0 part of titanium oxide powder having photocatalytic activity [manufactured by Ishihara Techno Co., Ltd .; trade name ST-01] was added and uniformly dissolved and dispersed (toluene). The titanium oxide content in the removed silicone elastomer composition was 3.25%). The silicone elastomer composition thus obtained was applied to the surface of the tarpaulin base cloth in the same manner as in Example 1 to a thickness of 200 μm using an applicator to prepare a silicone elastomer coated base cloth. In the obtained base fabric, the titanium oxide powder having a photocatalytic ability was not retained on the surface layer of the silicone elastomer coating, but was dispersed in the silicone elastomer. The discoloration and fading of this silicone elastomer-coated base cloth after irradiation with ultraviolet rays was measured in the same manner as in Example 1. The results are shown in Table 1.

【0028】

[table 1]

<img file="JPH10202794A_D0001.tif" />【0029】

[Example 2]

Add 2 parts of sodium lauryl sulfate and 70 parts of water to 100 parts of dimethylpolysiloxane that seals the silanol groups at both ends with a degree of polymerization of 30, and 350 kg / cm.²The homogenizer was passed twice under the pressure of. Next, 1 part of dodecylbenzenesulfonic acid was added as a polymerization initiator, emulsion polymerization was carried out at room temperature for 16 hours, and then the pH was adjusted to 7 using a sodium hydroxide solution, and both ends having a molecular weight of about 200,000. Emulsion A of silanol group-blocking dimethylpolysiloxane was prepared. On the other hand, 10 parts of sodium lauryl sulfate and 40 parts of water were added to 40 parts of dioctyl tin dilaurate, and then this was passed through a homogenizer to prepare emulsion B. 100 parts of emulsion A, 1.5 parts of emulsion B, 25 parts of colloidal silica aqueous dispersion (solid content 30% by weight) and titanium oxide powder for pigment (particle size 570 nm, specific surface area 11 m)²/ g) After 7.5 parts are mixed uniformly, diethylamine is added to adjust the pH to 11, and this is aged at room temperature of 25 ° C for 2 weeks to form an organopolysiloxane emulsion composition for a silicone water-based elastomer. Was prepared. Glass fiber woven fabric cut to a size of 30 x 30 cm on a glass plate [plain weave, weave density 18 (vertical) x 17 (horizontal), weight 405 g / m², Thickness 0.37 mm] was placed, and the above-mentioned organopolysiloxane emulsion composition was applied to a thickness of 200 μm on the surface of this woven fabric using an applicator. Immediately after application, titanium oxide powder with photocatalytic activity wrapped in 6 layers of gauze [manufactured by Ishihara Techno Co., Ltd .; trade name ST-01, X-ray particle size measurement 5 nm, specific surface area 300 m²Titanium oxide fine powder with strong photocatalytic activity of / g] was sprayed evenly by tapping lightly from a height of 30 cm (3 g / m).²). After spraying, the organopolysiloxane emulsion composition was cured by drying at room temperature to prepare a silicone elastomer-coated woven fabric. The discoloration and fading of the obtained woven fabric after irradiation with ultraviolet rays was measured in the same manner as in Example 1. The results are shown in Table 2. The discoloration and fading of the silicone elastomer-coated woven fabric of the present invention was remarkably large, and the oxidative decomposition effect of the titanium oxide powder having photocatalytic activity was remarkable.

【0030】

[Comparative Example 3]

To 100 parts of the organopolysiloxane emulsion composition for silicone water-based elastomer prepared in Example 2, 1.0 part of titanium oxide powder having photocatalytic activity [manufactured by Ishihara Techno Co., Ltd .; trade name ST-01] was added uniformly. It was dissolved and dispersed. The organopolysiloxane emulsion composition thus obtained was applied to the surface of a glass fiber woven fabric similar to that in Example 2 to a thickness of 200 μm using an applicator to prepare a silicone elastomer-coated woven fabric. In the obtained woven fabric, the titanium oxide powder having a photocatalytic ability was not retained on the surface layer of the silicone elastomer coating, but was dispersed in the silicone elastomer. The discoloration and fading of this silicone elastomer-coated woven fabric after irradiation with ultraviolet rays was measured in the same manner as in Example 1. The results are shown in Table 2.

【0031】

[Table 2]

<img file="JPH10202794A_D0002.tif" />【0032】

[Example 3]

100 parts of silanol group-blocking dimethylpolysiloxane with a viscosity of 20,000 cm Stokes, 15 parts of fumed silica [manufactured by Aerosil Japan; trade name Aerosil 300] and 3.5 parts of both-terminal silanol group-blocking dimethylpolysiloxane plasticizer with a degree of polymerization of Was added and kneaded at 150 ° C. for 2 hours to obtain a silicone elastomer base. Next, 15 parts of toluene and 12 parts of vinyltrioxymsilane were added to 100 parts of this base to prepare a silicone elastomer composition. An airbag base cloth (made of nylon 66) having a size of 30 × 30 cm was placed on a glass plate, and the silicone elastomer composition was applied to a thickness of 200 μm on the surface of the base cloth using an applicator. Immediately after application, titanium oxide powder with photocatalytic activity wrapped in 6 layers of gauze [manufactured by Ishihara Techno Co., Ltd .; trade name ST-01, X-ray particle size measurement 5 nm, specific surface area 300 m²Titanium oxide fine powder with strong photocatalytic activity of / g] was sprayed evenly by tapping lightly from a height of 30 cm (3 g / m).²). After spraying, the silicone elastomer composition was cured by leaving it at room temperature overnight to prepare a silicone elastomer coated base fabric. The discoloration and fading of the obtained base cloth after irradiation with ultraviolet rays was measured in the same manner as in Example 1. The results are shown in Table 3. The discoloration and fading of the silicone elastomer-coated base fabric of the present invention was remarkably large, and the oxidative decomposition effect of the titanium oxide powder having photocatalytic activity was remarkable.

【0033】

[Comparative Example 4]

In Example 3, a silicone elastomer-coated base cloth was prepared in the same manner as in Example 3 except that the titanium oxide powder having a photocatalytic ability was not sprayed. The discoloration and fading of the obtained base cloth after irradiation with ultraviolet rays was measured in the same manner as in Example 1. The results are shown in Table 3.

【0034】

[Table 3]

<img file="JPH10202794A_D0003.tif" />【0035】

[Example 4]

The silicone elastomer-coated base cloth prepared in Example 1 was applied to a weather resistance test exposure table installed at 45 degrees southward on the roof of a four-story building located in an oil factory area where soot and the like are relatively easy to adhere. , Fixed in a floating state in the air. This base cloth was exposed to wind and rain from April 1996, and the contamination after 3 months and 6 months was judged by JIS L 0805 gray scale for contamination in comparison with the unexposed product. The results are shown in Table 4. The oxidative decomposition force on the surface of the silicone elastomer coating base cloth of the present invention was remarkable even after 6 months, and no stain was observed.

【0036】

[Comparative Example 5]

In the same manner as in Example 4, the stainability of the silicone elastomer-coated base fabric prepared in Comparative Example 1 was measured after 3 months and 6 months. The results are shown in Table 4.

【0037】

[Comparative Example 6]

In the same manner as in Example 4, the stainability of the silicone elastomer-coated base fabric prepared in Comparative Example 2 was measured after 3 months and 6 months. The results are shown in Table 4.

【0038】

[Comparative Example 7]

The silicone elastomer composition prepared in Example 1 was applied to the same surface of the tarpaulin base cloth as in Example 1 to a thickness of 200 μm using an applicator. After heating this in an oven at 130 ° C for 3 minutes to cure it, titanium oxide powder having photocatalytic activity on the surface of the cured product [manufactured by Ishihara Techno Co., Ltd .; trade name ST-01, X-ray particle size measurement 5 nm, Specific surface area 300m²Titanium oxide fine powder with strong photocatalytic activity of / g] was sprayed in the same manner as in Example 1 to prepare a silicone elastomer-coated base cloth. The titanium oxide powder on the obtained base fabric was only adhered to the surface of the silicone elastomer coating and was not completely adhered. The stainability of this silicone elastomer-coated base fabric after 3 months and 6 months was measured in the same manner as in Example 4. The results are shown in Table 4.

【0039】

[Table 4]

<img file="JPH10202794A_D0004.tif" />【0040】

[Effect of the invention]

The silicone elastomer-coated sheet-like material of the present invention is characterized in that titanium oxide powder having photocatalytic activity is adhered to the surface layer portion, so that dirt does not easily adhere to the surface layer, and even if dirt adheres, it can be easily decomposed and removed. Has. Further, since this titanium oxide powder is supported in the silicone elastomer, it has an advantage that the antifouling effect is maintained. Further, the production method of the present invention has an advantage that the sheet-like product of the present invention can be produced with high productivity.