JP2005319601A - Hydrophilizing stainproof method of water repellent substrate and its use in artificial article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrophilizing stainproof method of a water repellent substrate capable of well preventing the staining of the surface of the water repellent substrate over a long period of time without deteriorating the water repellent substrate and reducing the decorative properties thereof. <P>SOLUTION: A hydrophobic silicone compound-containing layer is formed on the surface of the water repellent substrate and a metal dope titanium oxide-containing layer containing titanium oxide, which is doped with at least one metal element selected from the group consisting of copper, manganese, nickel, cobalt, iron and zinc, is formed on the surface of the hydrophobic silicone compound-containing layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for hydrophilizing and antifouling a water-repellent substrate, and also relates to the use of a substrate treated by the method in an artificial product.

  In order to improve the stain resistance and cosmetic properties of various artifacts such as buildings, civil engineering works and equipment used indoors and outdoors, and to protect the artifacts from water-repellent substances such as fluororesin It is known to form a coating film on the surface of the artifact. In some cases, the surface itself is made of a water-repellent substance.

  It is also known that the surface of a water-repellent substance can be made hydrophilic in order to improve the stain resistance. For example, a hydrophilic substance such as silica is added to the water-repellent substance. Things have been done. However, in such a method, since the hydrophilic substance gradually deteriorates due to the action of light or the like, it is difficult to maintain the hydrophilicity of the surface at a sufficient level for a long time.

Therefore, in recent years, in order to impart long-term hydrophilicity and further a self-cleaning function, for example, as described in JP-A-6-278241, an anatase-type titanium oxide is a main component on a substrate. The photocatalyst layer is also formed directly.
JP-A-6-278241

  However, it has been reported that when anatase-type titanium oxide is directly formed on a water-repellent organic substrate, the substrate is decomposed or deteriorated due to its photocatalytic action (Otani sentence, polymer processing 42, No. 5, p18 (1993)), it is not preferable to directly form a photocatalytic layer made of anatase-type titanium oxide on the surface of a water-repellent organic substrate.

  In addition, if the photocatalyst layer thickness is increased to enhance the antifouling function, interference color is generated due to the optical properties of titanium oxide, which has a high refractive index, resulting in a decrease in transparency. There is a risk of causing.

  When the substrate contains a water repellent component, it is difficult to prevent the water repellent component from blocking the water repellent group of the water repellent substrate and from the water repellent substrate even if it has a photocatalyst layer. It was not easy to decompose and remove the water repellent component that appeared.

  The present invention is for solving the above-mentioned problems, and the water repellency can be satisfactorily self-cleaned over a long period of time without decomposing / degrading the water repellent substrate or reducing its cosmetic properties. An object of the present invention is to provide a hydrophilic antifouling method for a substrate.

  An object of the present invention is to form a hydrophobic silicone compound-containing layer on the surface of a water-repellent substrate, and a metal selected from the group consisting of copper, manganese, nickel, cobalt, iron and zinc on the surface of the hydrophobic silicone compound-containing layer This is achieved by a hydrophilic antifouling method for forming a metal-doped titanium oxide-containing layer containing titanium oxide doped with at least one of the elements. The substrate treated by the hydrophilization antifouling method of the present invention can be suitably used for the production of artificial objects such as buildings, civil engineering works, various equipment and the like, and is particularly preferable as a building member (building material).

  The metal-doped titanium oxide-containing layer is an amorphous type and / or anatase type titanium having a peroxo group doped with at least one metal element selected from the group consisting of copper, manganese, nickel, cobalt, iron and zinc. It is preferably formed from a dispersion of fine oxide particles. Moreover, it is preferable that the dispersion liquid further contains a silicone compound, and a polyether-modified silicone oil is suitable as the silicone compound.

  The hydrophobic silicone compound contained in the hydrophobic silicone compound-containing layer formed on the surface of the water-repellent substrate is preferably a silicone resin.

  The hydrophilic antifouling method of the present invention is a water repellent substrate having at least a surface thereof made of silicone, modified silicone, polyvinyl chloride, fluororesin, polycarbonate or acrylic polymer, in particular, a sealing material made of silicone or modified silicone or its periphery. Suitable for a substrate.

  The hydrophilic antifouling method of the present invention improves the antifouling function by hydrophilizing the water-repellent substrate, and exhibits a unique self-cleaning effect different from the photocatalytic function exhibited by the metal-doped titanium oxide-containing layer itself. Surface contamination can be prevented over a long period of time. The self-cleaning effect can be further improved by blending a silicone compound, particularly a polyether-modified silicone oil, into the metal-doped titanium oxide-containing layer.

  Since the metal-doped titanium oxide-containing layer does not have a photocatalytic function, the hydrophobic silicone compound-containing layer and the water-repellent organic substrate are not decomposed by the photocatalytic function. Therefore, the hydrophilic antifouling method of the present invention can impart a long-term antifouling function to any water-repellent substrate, and is particularly suitable as a surface antifouling method for artificial materials such as building materials and buildings used outdoors. is there.

  Further, even if the thickness of the metal-doped titanium oxide-containing layer is increased due to the optical action of the hydrophobic silicone compound-containing layer, the cosmetic properties of the water-repellent substrate do not change. Therefore, an arbitrary design can be provided by making use of the texture and color of the water-repellent substrate itself.

  In the present invention, even when the substrate contains a water-repellent component, it is possible to prevent the water-repellent component from eluting from the water-repellent substrate, and the water-repellent component appears on the surface of the substrate. Can be easily disassembled and removed. Therefore, according to the present invention, it has become possible to impart a surface hydrophilization and a self-cleaning function to the silicone-based sealing material and its peripheral substrate, which have been difficult until now.

  The water-repellent substrate to be subjected to the hydrophilization antifouling method of the present invention is not particularly limited, and various inorganic substrates and organic substrates, or a combination thereof can be used.

  Examples of the inorganic substrate include a substrate made of a metal such as aluminum. Examples of the organic substrate include a substrate made of a substance such as an organic resin, wood, or paper. More specific examples of the organic resin include, for example, modified silicones such as fluorine resin, acrylic resin, polyethylene, polypropylene, polycarbonate, polyacrylate, polyester, polyamide, polyurethane, ABS resin, polyvinyl chloride, silicone, and acrylic silicone. Can be mentioned. In particular, silicone, modified silicone, polyvinyl chloride, fluororesin, polycarbonate, and acrylic polymer are preferable. The shape of the substrate is not particularly limited, and can be any shape such as a cube, a rectangular parallelepiped, a sphere, and a sheet. The substrate may be porous.

  As the water repellent organic base, it is also possible to use a silicone sealant made of a silicone base. The silicone-based substrate may contain a water-repellent component such as silicone oil. Examples of such silicone sealants include SH780, SE960, and SE5088 (manufactured by Toray Dow Corning Silicone Co., Ltd.). Moreover, the peripheral base material of this sealing material can also be used. Examples thereof include a water-repellent substrate adjacent to the sealing material and a peripheral substrate in which water repellency is expressed by a water-repellent component eluted from the sealing material.

  The water repellent substrate that is the subject of the present invention only needs to be water repellent at least on the surface to be hydrophilized. Therefore, even a substrate made of a hydrophilic substance such as glass, metal oxide, ceramics, concrete, or mortar can be a target for the hydrophilization antifouling method of the present invention as long as the surface thereof has been subjected to water repellency treatment.

  Although any treatment method can be used as the water repellency treatment, a typical water repellency treatment includes a coating treatment with a hydrophobic coating material. Examples of hydrophobic coating materials include fluororesins, alkyd resins, acrylic resins, amino resins, urethane resins, epoxy resins, silicone resins, acrylic silicone resins, and other modified silicone resins, unsaturated polyester resins, ultraviolet curable resins, and phenols. A so-called paint coating containing a synthetic resin such as a resin, a vinyl chloride resin, and other synthetic resins and a colorant can be suitably used.

  The thickness of the coating film obtained by the coating treatment is preferably 0.01 to 100 μm, more preferably 0.1 to 50 μm, and particularly preferably 0.5 μm to 10 μm.

  Examples of the coating means that can be used include spray coating, dip coating, flow coating, spin coating, roll coating, brush coating, and sponge coating. In order to improve the physical performance such as the hardness of the coating film and the adhesion to the substrate, it is desirable to heat within the allowable range of the substrate and the coating film.

  In the hydrophilization antifouling method of the present invention, a hydrophobic silicone compound-containing layer exists on the water-repellent substrate. The hydrophobic silicone compound-containing layer has a function of fixing a metal-doped titanium oxide-containing layer described later to a water-repellent substrate, and also has a function of preventing coloring by the metal-doped titanium oxide layer. Further, the hydrophobic silicone compound-containing layer has a function of preventing moisture from entering the substrate and a function of blocking the expression of hydrophobic groups of the water-repellent substrate.

  Although the hydrophobic silicone compound which comprises a hydrophobic silicone compound content layer is not specifically limited, A silicone resin is preferable. Specific examples of particularly preferred hydrophobic silicone compounds include room temperature curable methyl silicone resins and room temperature curable methyl phenyl silicone resins. Examples of such room temperature curable silicone resins include SR2316 and SR2410 (manufactured by Toray Dow Corning Silicone Co., Ltd.).

  Examples of other hydrophobic silicone compounds include hydrolyzable silanes, hydrolysates thereof, and various organopolysiloxanes. Various alkoxysilanes can be used as the hydrolyzable silane, and specific examples include tetraalkoxysilane, alkyltrialkoxysilane, dialkyldialkoxysilane, and trialkylalkoxysilane. Of these, one type of hydrolyzable silane may be used alone, or two or more types of hydrolyzable silanes may be mixed and used as necessary. Examples of the organopolysiloxane include various organopolysiloxanes such as amino-modified siloxane, epoxy-modified siloxane, and long-chain alkyl-modified siloxane. Examples of such silanes and organopolysiloxanes include AY43-206E and BY16-606 (manufactured by Toray Dow Corning Silicone Co., Ltd.).

  The hydrophobic silicone compound-containing layer may be colorless and transparent, or may be colored transparent, translucent or opaque. Coloring here includes not only red, blue, green, etc. but also white. In order to obtain a colored hydrophobic silicone compound-containing layer, it is preferable to add various colorants such as inorganic or organic pigments or dyes to the hydrophobic silicone compound-containing layer.

  Examples of the inorganic pigment include carbon black, graphite, yellow lead, iron oxide yellow, red lead, bengara, ultramarine blue, chromium oxide green, iron oxide and the like. As organic pigments, azo organic pigments, phthalocyanine organic pigments, selenium organic pigments, quinocridone organic pigments, dioxazine organic pigments, isoindolinone organic pigments, diketopyrrolopyrrole and various metal complexes can be used. Those having excellent light resistance are desirable. Examples of light-resistant organic pigments include Hansa Yellow, toluidine red, which are insoluble azo organic pigments, phthalocyanine blue B, phthalocyanine green, which are phthalocyanine organic pigments, and quinacridone red, which is a quinacridone organic pigment. It is done.

  Examples of the dye include basic dyes, direct dyes, acid dyes, vegetable dyes, and the like, but those having excellent light resistance are preferable. For example, direct scarlet for red, direct lorseline, azorubine, orange for direct orange R For conch, acid orange and yellow, chrysophenine NS, methanol yellow, for brown, direct brown KGG, acid brown R, for blue, direct blue B, for black, direct black GX, nigrosine BHL, etc. are particularly preferred.

  When the hydrophobic silicone compound-containing layer contains a colorant, the mixing ratio (weight ratio) of the hydrophobic silicone compound and the colorant is preferably in the range of 1: 2 to 1: 0.05, and 1: 1 to 1 : The range of 0.1 is more preferable.

  In addition, additives, such as a dispersing agent, a stabilizer, a leveling agent, may be further mix | blended with the hydrophobic silicone compound content layer. These additives have the effect of facilitating the formation of the hydrophobic silicone compound-containing layer. Further, when a colorant such as a pigment / dye is blended, it is also possible to add a binder for fixing the colorant. As the binder in this case, various binders for coatings mainly composed of an acrylic ester or an acrylic ester copolymer resin having excellent weather resistance can be used. Product), Polysol AP-609 (manufactured by Showa Polymer Co., Ltd.) and the like.

  The hydrophobic silicone compound-containing layer can be formed, for example, as follows. A solution containing a hydrophobic silicone compound and, if necessary, the colorant, the additive and the binder in a volatile solvent is applied to the surface of the water-repellent substrate so as to have a thickness of about 0.1 to 5 mm. . Heating is performed as necessary to evaporate the volatile solvent to form a hydrophobic silicone compound-containing layer on the water-repellent substrate. When the hydrophobic silicone compound-containing layer is colored, it is possible to impart colored cosmetic properties to the water-repellent substrate by integrating with the water-repellent substrate.

  The thickness of the hydrophobic silicone compound-containing layer formed as described above is not particularly limited, but is preferably 0.01 to 1.0 μm, and more preferably 0.05 to 0.3 μm. Moreover, when a coloring agent, an additive, and a binder are added, 1.0 micrometer-100 micrometers are preferable, and 10 micrometers-50 micrometers are more preferable.

  As a method for forming a hydrophobic silicone compound-containing layer on a water-repellent substrate, any known method can be used. For example, spray coating method, dip coating method, flow coating method, spin coating method, roll coating method. Brush coating, sponge coating, etc. are possible. In order to improve the physical properties such as the hardness of the hydrophobic silicone compound-containing layer and the adhesion to the water-repellent substrate, these are acceptable after the formation of the hydrophobic silicone compound-containing layer on the water-repellent substrate. It is preferable to heat at the inner temperature.

In the hydrophilization antifouling method of the present invention, titanium oxide doped with at least one metal element selected from the group consisting of copper, manganese, nickel, cobalt, iron and zinc on the hydrophobic silicone compound-containing layer A metal-doped titanium oxide-containing layer containing is formed. Titanium oxide includes various oxides and peroxides such as TiO ₂ , TiO ₃ , TiO, and TiO ₃ / nH ₂ O, and may be any of amorphous type, anatase type, brookite type, and rutile type. .

  The metal-doped titanium oxide comprises a titanium oxide comprising one or more metal elements selected from the group consisting of copper, manganese, nickel, cobalt, iron and zinc, preferably having a peroxo group, The property is fine particles or powder. The titanium oxide having a peroxo group may be any of amorphous type, anatase type, brookite type, rutile type, or a mixture thereof.

  Amorphous titanium oxide does not have a photocatalytic function. On the other hand, anatase type, brookite type, and rutile type titanium oxides have a photocatalytic function. However, when copper, manganese, nickel, cobalt, iron, or zinc is combined at a certain concentration or more, the photocatalytic function is lost. Therefore, the metal-doped titanium oxide used in the present invention does not have a photocatalytic function. Amorphous titanium oxide is converted to anatase titanium oxide over time by heating with sunlight, etc., but as described above, when combined with copper, manganese, nickel, cobalt, iron or zinc, anatase titanium oxide Loses its photocatalytic function, so that, ultimately, the metal-doped titanium oxide does not exhibit a photocatalytic function over time.

  On the other hand, the metal-doped titanium oxide exhibits a non-photocatalytic type unique antifouling action. Thereby, contamination of the surface of the metal-doped titanium oxide-containing layer is prevented or reduced. Although the mechanism of this action is unknown, it is thought to be due to a complex action based on the photo-oxidation reaction caused by short-wave electromagnetic waves such as ultraviolet rays (sunlight) and the electrical properties of the metal-doped titanium oxide-containing layer side. .

In this photo-oxidation reaction, active oxygen such as hydroxyl radical (.OH), ¹ O ₂ (singlet oxygen) is generated from oxygen and / or moisture in the air or organic matter by a short wavelength electromagnetic wave, and these are layered. It is a concept that includes reacting with organic / inorganic substances adhering to the surface. It is thought that positive charges are generated in organic / inorganic materials.

  The metal-doped titanium oxide-containing layer is positively charged as a whole because the doped metal has a positive charge. Accordingly, the metal-doped titanium oxide-containing layer having a positive charge is electrically repelled in the same manner as the organic / inorganic substance having a positive charge, and the organic / inorganic substance is relatively easily doped with the metal by the action of external force such as flowing water and wind / rain. It will be removed from the surface of the titanium oxide-containing layer. Thereby, it is thought that contamination of the metal-doped titanium oxide layer-containing surface can be suppressed or reduced.

  As a method for producing a metal-doped titanium oxide, a production method based on a hydrochloric acid method or a sulfuric acid method, which is a common method for producing titanium dioxide powder, may be employed, or a method for producing various liquid-dispersed titania solutions. May be adopted. And the said metal can be compounded with a titanium oxide regardless of a manufacturing stage.

  For example, specific methods for producing the metal-doped titanium oxide include the following first to third production methods and conventionally known sol-gel methods.

First Production Method First, a titanium hydroxide is formed by reacting a tetravalent titanium compound such as titanium tetrachloride with a base such as ammonia. Next, this titanium hydroxide is peroxo-oxidized with an oxidizing agent to form ultrafine particles of amorphous titanium peroxide. This reaction is preferably carried out in an aqueous medium. Furthermore, it is also possible to transfer to anatase-type titanium peroxide by arbitrary heat treatment. In any of the above steps, at least one of copper, manganese, nickel, cobalt, iron, zinc, or a compound thereof is mixed.

  The peroxidation oxidizing agent is not particularly limited, and various agents can be used as long as they can form a titanium peroxo compound, that is, titanium peroxide, but hydrogen peroxide is preferred. When hydrogen peroxide is used as the oxidizing agent, the concentration of hydrogen peroxide is not particularly limited, but is preferably 30 to 40%. It is preferred to cool the titanium hydroxide before peroxolation. The cooling temperature at that time is preferably 1 to 5 ° C.

  FIG. 1 shows an example of the first manufacturing method. In the illustrated production method, an aqueous solution of titanium tetrachloride and aqueous ammonia are mixed in the presence of at least one compound of copper, manganese, nickel, cobalt, iron, and zinc, and the metal hydroxide and titanium water are mixed. An oxide mixture is formed. The concentration and temperature of the reaction mixture at that time are not particularly limited, but are preferably diluted and at room temperature. This reaction is a neutralization reaction, and it is preferable that the pH of the reaction mixture is finally adjusted to around 7.

  The metal and titanium hydroxides thus obtained are washed with pure water, cooled to around 5 ° C., and then peroxoated with hydrogen peroxide. As a result, an aqueous dispersion containing fine titanium oxide particles having amorphous peroxo groups doped with metal, that is, an aqueous dispersion containing the metal-doped titanium oxide according to the present invention can be produced. .

Second Production Method A tetravalent titanium compound such as titanium tetrachloride is peroxo-oxidized with an oxidizing agent, and this is reacted with a base such as ammonia to form amorphous fine titanium peroxide. This reaction is preferably carried out in an aqueous medium. Furthermore, it is possible to transfer to anatase-type titanium peroxide by arbitrarily heat-treating. In any of the above steps, at least one of copper, manganese, nickel, cobalt, iron, zinc, or a compound thereof is mixed.

Third production method A tetravalent titanium compound such as titanium tetrachloride is reacted simultaneously with an oxidizing agent and a base to simultaneously form titanium hydroxide and peroxidize it to form amorphous titanium peroxide with ultrafine particles. Form. This reaction is preferably carried out in an aqueous medium. Furthermore, it is possible to transfer to anatase-type titanium peroxide by arbitrarily heat-treating. In any of the above steps, at least one of copper, manganese, nickel, cobalt, iron, zinc, or a compound thereof is mixed.

  In the first to third manufacturing methods, it goes without saying that a mixture of amorphous titanium peroxide and anatase titanium peroxide obtained by heating the same can be used as the metal-doped titanium oxide.

Production Method by Sol-Gel Method A titanium alkoxide is mixed and stirred with a solvent such as water or alcohol, an acid or a base catalyst, and the titanium alkoxide is hydrolyzed to produce a sol solution of ultrafine titanium oxide. Before or after the hydrolysis, at least one of copper, manganese, nickel, cobalt, iron, zinc, or a compound thereof is mixed. The titanium oxide thus obtained is an amorphous type having a peroxo group.

As the titanium alkoxide, a compound represented by the general formula: Ti (OR ′) ₄ (where R ′ is an alkyl group), or one or two alkoxide groups (OR ′) in the general formula is a carboxyl group. Alternatively, a compound substituted with a β-dicarbonyl group or a mixture thereof is preferable.

Specific examples of the titanium alkoxide include Ti (O—isoC ₃ H ₇ ) ₄ , Ti (O—nC ₄ H ₉ ) ₄ , Ti (O—CH ₂ CH (C ₂ H ₅ ) C ₄ H ₉ ) _4. , Ti (O—C ₁₇ H ₃₅ ) ₄ , Ti (O—isoC ₃ H ₇ ) ₂ [CO (CH ₃ ) CHCOCH ₃ ] ₂ , Ti (O—nC ₄ H ₉ ) ₂ [OC ₂ H ₄ N ( _{C 2 H 4 OH) 2]} 2, Ti (OH) 2 [OCH (CH 3) COOH] 2, Ti (OCH 2 CH (C 2 H 5) CH (OH) C 3 H 7) 4, Ti (O _{-nC 4 H 9) 2 (OCOC} 17 H 35) , and the like.

Tetravalent Titanium Compound The tetravalent titanium compound used in the production of the metal-doped titanium oxide used in the present invention is water that is also called orthotitanic acid (H ₄ TiO ₄ ) when reacted with a base. Various titanium compounds can be used as long as they can form titanium oxide. Examples thereof include water-soluble inorganic acid salts of titanium such as titanium tetrachloride, titanium sulfate, titanium nitrate, and titanium phosphate. In addition, water-soluble organic acid salts of titanium such as titanium oxalate can be used. Of these various titanium compounds, titanium tetrachloride is preferred because it is particularly excellent in water solubility and no components other than titanium remain in the dispersion of metal-doped titanium oxide.

  When a solution of a tetravalent titanium compound is used, the concentration of the solution is not particularly limited as long as a titanium hydroxide gel can be formed, but a relatively dilute solution is preferable. Specifically, the solution concentration of the tetravalent titanium compound is preferably 5 to 0.01 wt%, and more preferably 0.9 to 0.3 wt%.

As the base to be reacted with the tetravalent titanium compound, various bases can be used as long as they can react with the tetravalent titanium compound to form titanium hydroxide. For example, ammonia, caustic soda, sodium carbonate Examples thereof include caustic potash, and ammonia is preferable.

  When the above base solution is used, the concentration of the solution is not particularly limited as long as a titanium hydroxide gel can be formed, but a relatively dilute solution is preferable. Specifically, the concentration of the base solution is preferably 10 to 0.01 wt%, and more preferably 1.0 to 0.1 wt%. In particular, the concentration of ammonia when ammonia water is used as the base solution is preferably 10 to 0.01 wt%, and more preferably 1.0 to 0.1 wt%.

Metal compound Examples of the compound of copper, manganese, nickel, cobalt, iron, or zinc are as follows.
Ni compound: Ni (OH) ₂ , NiCl ₂
Co compound: Co (OH) NO ₃ , Co (OH) ₂ , CoSO ₄ , CoCl ₂
Cu compound: Cu (OH) ₂ , Cu (NO ₃ ) ₂ , CuSO ₄ , CuCl ₂ ,
Cu (CH ₃ COO) ₂
Mn compound: MnNO ₃ , MnSO ₄ , MnCl ₂
Fe compound: Fe (OH) ₂ , Fe (OH) ₃ , FeCl ₃
Zn compound: Zn (NO ₃ ) ₂ , ZnSO ₄ , ZnCl ₂

  The titanium peroxide concentration (total amount including coexisting copper, manganese, nickel, cobalt, iron or zinc) in the aqueous dispersion obtained by the first to third production methods is preferably 0.05 to 15 wt%, 0.1-5 wt% is more preferable. Moreover, about the compounding quantity of copper, manganese, nickel, cobalt, iron, and zinc, 1: 0.01-1: 0.5 are preferable at the molar ratio of titanium and a metal component, and 1: 0.03-1 : 0.1 is more preferable.

Surfactant and Dispersant It is preferable to add a surfactant or dispersant that facilitates layer formation to the aqueous dispersion of metal-doped titanium oxide obtained by the first to third production methods. As the surfactant or dispersant, for example, a silane compound, silicone oil, silicone rubber, silicone powder, silicone resin and the like are preferable.

  Examples of the surfactant that can be used include TSF4445, TSF4446 (manufactured by GE Toshiba Silicone Co., Ltd.), SH200 (manufactured by Toray Dow Corning Silicone Co., Ltd.), KP series (manufactured by Shin-Etsu Chemical Co., Ltd.), and the like. it can.

  As the dispersant, for example, DC3PA, ST86A (manufactured by Toray Dow Corning Silicone Co., Ltd.) or the like can be used.

  Moreover, it is also possible to mix | blend the silane compound which has an amino group, an epoxy group, and a methacryloxy group, and what is called a silane coupling agent. This coupling agent makes it possible to improve the hardness of the metal-doped titanium oxide-containing layer and the adhesion with an adjacent layer.

  The mixing ratio (wt%) between the metal-doped titanium oxide and the surfactant and / or dispersant is preferably 1: 0.02 to 1:20, more preferably 1: 0.05 to 1:10.

  The metal-doped titanium oxide-containing layer formed in the present invention can be produced by applying an aqueous dispersion containing a metal-doped titanium oxide on the hydrophobic silicone compound-containing layer and then drying it. The thickness of the metal-doped titanium oxide-containing layer is preferably 0.01 μm to 2.0 μm, more preferably 0.1 μm to 1.0 μm. As the coating method, a general-purpose film forming method such as brush coating, roller coating, spray coating or the like can be used.

  In order to impart higher antifouling performance to the surface of the metal-doped titanium oxide-containing layer, it is desirable to add a silicone compound to the metal-doped titanium oxide-containing layer.

  Various types of silicone compounds can be used. Of these, polyether-modified silicone oil is preferable. Specifically, at the molecular chain terminal or side chain, polyethylene oxide, polypropylene oxide, polybutylene oxide, polyethylene oxide-polypropylene oxide copolymer block, polyethylene oxide-polybutylene oxide copolymer are used. Examples thereof include organopolysiloxanes having a structure such as a polymer block, a polypropylene oxide-polybutylene oxide copolymer block, and the like. Among these, an organopolysiloxane in which a polyethylene oxide, polypropylene oxide, or polyethylene oxide-polypropylene oxide copolymer block is bonded to a silicon atom via an alkylene group is preferable. Such a polyether-modified silicone oil can be produced by a known method, for example, by the method described in JP-A-9-165318. Examples of such polyether-modified silicone oil include SH3746, SH30PA, etc. (manufactured by Toray Dow Corning Silicone Co., Ltd.).

  The mixing ratio of the metal-doped titanium oxide and the silicone compound is preferably 1: 0.002 to 1:20, and more preferably 1: 0.05 to 1:10.

  Moreover, when a silicone compound is included, 0.01-1.0 micrometer is preferable and, as for the thickness of a metal dope titanium oxide content layer, 0.05-0.3 micrometer is more preferable.

  Since the metal-doped titanium oxide-containing layer does not have a photocatalytic function, even if it receives light energy such as ultraviolet rays, the constituent materials of adjacent layers, particularly organic substances, are not deteriorated by the photocatalytic function. Therefore, the hydrophobic silicone compound-containing layer is not deteriorated by the action of the metal-doped titanium oxide-containing layer. Moreover, organic resin, such as an acrylic resin, a polyester resin, a polycarbonate resin, can also be mixed with the metal dope titanium oxide containing layer itself as needed.

  Further, when the metal-doped titanium oxide-containing layer contains a silicone compound, in particular, a polyether-modified silicone oil, it is excellent in maintaining hydrophilic expression, and the metal-doped titanium oxide-containing layer and the substrate surface in contact with the layer are deteriorated. In particular, the effect of suppressing or reducing color deterioration (fading) or contamination of the layer surface with organic or inorganic substances is enhanced.

  The hydrophilic antifouling method of the present invention can be used in various fields where various design properties and high antifouling / waterproof performance are required, such as glass, metal, ceramics, concrete, wood, stone, sealing material, etc. Combining building materials; air conditioner outdoor units; kitchen equipment; sanitary equipment; lighting equipment; automobiles; bicycles; motorcycles; airplanes; trains; The present invention is particularly preferable for building materials, and buildings such as houses, buildings, roads, and tunnels constructed using the building materials can exhibit a high waterproof / antifouling effect over time.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to an Example.

Reference example 1
To a solution in which 0.463 g of 97% CuCl ₂ · 2H ₂ O (cupric chloride: manufactured by Nippon Chemical Industry Co., Ltd.) is completely dissolved in 500 ml of pure water, a 50% titanium tetrachloride solution (manufactured by Sumitomo Sitix Corporation) is further added. 10 g was added, pure water was added, and the total volume was 1000 ml.

 A mixture of copper hydroxide and titanium hydroxide was precipitated by dropwise addition of dilute ammonia water obtained by diluting 25% ammonia water (manufactured by Takasugi Pharmaceutical Co., Ltd.) 10 times into this solution to pH 7.0.

 This precipitate was washed with pure water until the conductivity of the supernatant liquid became 0.8 mS / m or less, and the washing was terminated when the conductivity became 0.80 mS / m. Thereby, 340 g of a hydroxide-containing liquid having a concentration of 0.81 wt% was produced.

  Next, 25 g of 35% aqueous hydrogen peroxide (manufactured by Taiki Pharmaceutical Co., Ltd.) was added while cooling the hydroxide-containing liquid to 1 to 5 ° C., and the mixture was stirred for 16 hours. As a result, 365 g of a transparent green 0.90 wt% copper-doped amorphous titanium peroxide dispersion was obtained. This was diluted with pure water to prepare 385 g of a 0.85 wt% copper-doped amorphous titanium peroxide dispersion.

  Then, 0.4 wt% of polyether-modified silicone oil SH3746 (manufactured by Toray Dow Corning Silicone Co., Ltd.) was added thereto and stirred to obtain a film forming solution.

Example 1
A4 plate transparent float glass (thickness 3 mm) is coated with anatase-type titanium oxide dispersion (B56, manufactured by Sustainable Technology Co., Ltd.), heated at 300 ° C., and provided with a photocatalyst layer having a thickness of 0.1 μm Two sheets were made.

  Next, as shown in FIG. 2, the two substrates were pasted on a panel veneer using a double-sided tape at an interval of 10 mm between the joint plates. The joint was filled with a one-part silicone sealant (manufactured by Toray Dow Corning Silicone Co., Ltd .: SH780) and left outdoors for 2 months. A water repellency evaluation substrate in which the periphery of the sealing material was changed to water repellency by the water repellency component overflowing from the sealing material was prepared.

  After cleaning the surface of the water-repellent portion of the water-repellent evaluation substrate with pure water and performing a drying treatment, the water-repellent portion is coated with a room temperature-curing silicone resin coating agent (Toray Dow Corning Silicone Co., Ltd. A solution obtained by diluting 2) with toluene was brushed and dried to form a silicone resin-containing first layer.

The film-forming solution obtained in Reference Example 1 was applied to the surface of the first layer at a rate of 10 g / m ² using a low-pressure spray gun (manufactured by Chiron Japan Co., Ltd.) and dried at room temperature. Then, a copper-doped amorphous titanium oxide-containing second layer was formed.

Example 2
A4 size transparent float glass (thickness 3 mm) is coated with a fluororesin paint (manufactured by SK Kaken Co., Ltd .: Fluorolone) at a rate of 30 mg / m ² using a spray gun (manufactured by Meiji Machinery Co., Ltd.) A substrate was prepared by heating and drying at 120 ° C.

  Next, a silicone resin-containing first layer and a copper-doped amorphous titanium oxide-containing second layer were formed on the substrate surface.

Example 3
A silicone-based outer wall coloring paint (Toray Dow Corning Silicone Co., Ltd .: Wall Gart White) was applied to the surface of a commercially available concrete paving stone PC block using a brush and dried to prepare a substrate.

  Next, a silicone resin-containing first layer and a copper-doped amorphous titanium oxide-containing second layer were formed on the substrate surface.

Example 4
A tent ground (Toray Industries, Inc .: Cool Tent Soft: T-2850F) having a polyester fabric surface coated with a vinyl chloride resin was used as a substrate.

  Next, a silicone resin-containing first layer and a copper-doped amorphous titanium oxide-containing second layer were formed on the substrate surface.

Comparative Examples In Examples 1 to 4, the substrates that did not form the silicone resin-containing first layer and the copper-doped amorphous titanium oxide-containing second layer were referred to as Comparative Examples 1 to 4, respectively.

Evaluation 1
The laminates of Examples 1 to 4 were exposed outdoors in Saga Prefecture from November 2003 to February 2004 for 4 months. Thereafter, tap water was sprayed on the surface of the laminate, and the hydrophilicity and antifouling property were visually evaluated according to the following criteria. The results are shown in Table 1.

Hydrophilicity = ○: Water on the surface is flat Hydrophilicity = ×: Water on the surface is not flat Antifouling property = ○: Presence of contaminants is not observed on the surface Antifouling property = ×: Surface Spotted contaminants are found on the top

  From the results of Example 1 in Table 1, it is understood that the water repellent component of the sealing material can be prevented from being dissolved and decomposed by the laminate of the silicone resin-containing layer and the copper-doped amorphous titanium oxide-containing layer. From the results of Example 2-4 in Table 1, it can be seen that a hydrophilic antifouling function can be imparted to the water-repellent substrate. On the other hand, it can be seen from the results of Comparative Example 1 that the photocatalyst layer cannot prevent or decompose and remove the water-repellent component from the sealing material.

Example 5
As shown in FIG. 2, two sheets of A4 size transparent float glass (thickness 3 mm) were pasted on a panel veneer using a double-sided tape at an interval of 10 mm. The joint was filled with a one-part silicone sealing material (Toray Dow Corning Silicone Co., Ltd .: SE5088) with a reduced content of low molecular siloxane, and allowed to stand outdoors for 12 hours to dry the surface.

  Next, the surface of the sealing material is cleaned with pure water, dried, and then diluted with toluene at room temperature curable silicone resin coating agent (Toray Dow Corning Silicone Co., Ltd .: SR2410) on the surface of the sealing material. The resulting solution was brushed three times and dried to form a silicone resin-containing first layer.

Next, the film-forming solution obtained in Reference Example 1 was applied to the surface of the first layer at a rate of 10 g / m ² using a low-pressure spray gun (manufactured by Chiron Japan Co., Ltd.) and dried at room temperature. A copper-doped amorphous titanium oxide-containing second layer was formed.

Comparative Example 5
In Example 5, the copper-doped amorphous titanium oxide-containing second layer was not formed as Comparative Example 5.

Comparative Example 6
A substrate in which the silicone resin-containing first layer and the copper-doped amorphous titanium oxide-containing second layer were not formed in Example 5 was defined as Comparative Example 6.

Evaluation 2
The laminates of Example 5 and Comparative Examples 5 and 6 were sufficiently dried and then washed with running water to dry the surface. Outdoor exposure for 2 days. Tap water was sprayed on the surface of the laminate by spraying, and the hydrophilicity was visually evaluated according to the same criteria as in Evaluation 1. The results are shown in Table 2.

  From the results of Table 2, the combination of the silicone resin-containing layer and the copper-doped amorphous titanium oxide-containing layer can make the surface of the water-repellent sealant hydrophilic.

The figure which shows the outline of an example of the 1st manufacturing method of metal dope titanium oxide. Schematic which shows the example of preparation of the water-repellent evaluation board | substrate of Example 1 and 5

Claims (10)

Forming a hydrophobic silicone compound-containing layer on the surface of the water-repellent substrate,
A metal-doped titanium oxide-containing layer comprising a titanium oxide doped with at least one metal element selected from the group consisting of copper, manganese, nickel, cobalt, iron and zinc on the surface of the hydrophobic silicone compound-containing layer A hydrophilic antifouling method for a water-repellent substrate, characterized by comprising:   The metal-doped titanium oxide-containing layer is doped with at least one metal element selected from the group consisting of copper, manganese, nickel, cobalt, iron and zinc, and has an amorphous type and / or anatase type titanium having a peroxo group. The hydrophilization antifouling method according to claim 1, wherein the method is formed from a dispersion of fine oxide particles.   The hydrophilic antifouling method according to claim 2, wherein the dispersion further contains a silicone compound.   The hydrophilic antifouling method according to claim 3, wherein the silicone compound is a polyether-modified silicone oil.   The hydrophilic antifouling method according to any one of claims 1 to 4, wherein the hydrophobic silicone compound is a silicone resin.   The hydrophilic antifouling method according to any one of claims 1 to 5, wherein at least the surface of the water repellent substrate is made of silicone, modified silicone, polyvinyl chloride, fluororesin, polycarbonate or acrylic polymer.   The hydrophobizing antifouling method according to any one of claims 1 to 6, wherein the water-repellent substrate is a sealing material made of silicone or modified silicone or a peripheral substrate thereof.   A water-repellent substrate which has been subjected to a hydrophilic antifouling treatment by the method according to claim 1.   A building comprising the hydrophilic and antifouling treated water-repellent substrate. An architectural member comprising the water-repellent and antifouling treated water-repellent substrate.

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