JP2000135442A - Water-repellent substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-repellent substrate having both superior water repellency and a superior photocatalytic function on the surface, also having an antifouling effect and dew condensation preventing effect and preventing the deterioration of a water-repellent coating film by a photocatalyst layer even when the coating film is made of an organic polymer resin. SOLUTION: A water-repellent coating film 2 is formed on the surface of a base material 1 and a photocatalyst layer 3 using an anatase type titanium dioxide sol prepared by heating an amorphous titanium peroxide sol at >=100 deg.C is disposed on the coating film 2 to obtain the objective water-repellent substrate having superior water repellency and a superior photocatalyst function. Since a tough water absorption preventing layer having excellent durability in addition to superior water repellency and a superior photocatalytic function is formed on the surface of the base material, not only deterioration due to salt damage, frost damage, neutralization, or the like, but also the growth of algae are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cement molded product,
Construction materials such as stone tiles and metal tiles, civil engineering and buildings such as concrete, construction materials and monuments of stone materials such as sandstone, glasses,
Water-repellent treatment is applied to the surface of base materials such as glass products such as optical lenses, synthetic resin plates, plastic sheets, and synthetic resin products such as fibers, and the surface has a water-repellent and photocatalytic effect. And a water-repellent substrate comprising:

[0002]

2. Description of the Related Art Conventionally, the following are known as water-repellent substrates having a water-repellent action. For example, JP-A-7-29
No. 1667 discloses a transparent and water-repellent, absorbing and shielding ultraviolet and infrared ray without impairing optical properties.
In order to obtain a water-repellent ultraviolet ray infrared-absorbing glass which can sufficiently shield ultraviolet rays having a wavelength of around 00 nm, and has excellent durability such as adhesion, chemical resistance, and scratch resistance, a transparent substrate such as a glass substrate is used. On one side, a water-repellent thin film containing a silicon isocyanate compound and a fluoroalkylsilane compound is formed, and on the other surface of the substrate, a fluorescent whitening agent, an ultraviolet absorber and an infrared absorber are dissolved and added. An ultraviolet / infrared absorbing thin film formed by applying a resin-based primer coating solution and curing by heating, and a silicone-based hard coating solution in which a siloxane prepolymer is dissolved in an organic solvent is applied on the ultraviolet / infrared absorbing thin film. And water-repellent ultraviolet / infrared absorbing glass comprising a protective thin film formed by heating and curing to form a coating.

[0003] Japanese Patent Application Laid-Open No. Hei 8-143332 discloses a strong solid material that can prevent a surface of a substrate to be treated such as an optical element having an antireflection film from being contaminated for a long period of time and can always ensure a good surface. Before forming a water-repellent thin film, the surface of the substrate is activated by an ion beam method, a plasma method, a bombardment method, or the like, and a PVD method is applied to the activated surface. Discloses a method for forming a water-repellent organic silicon compound containing a perfluoro group.

Japanese Patent Application Laid-Open No. 8-12222 discloses a method for preventing the formation of streak-like dirt which is likely to occur in a portion where rainwater gathers and flows, such as under a window frame of a building. Using a surface treating agent containing 0.01 to 50% of a silane compound having a silanol group obtained by hydrolyzing a body, treating the surface of a hydrophobic synthetic resin coating film of an outdoor article with the surface treating agent to form a thin film. Is described.

A water-repellent member having a water-repellent function and a photocatalytic function on its surface is also known. For example, JP-A-9-228073 discloses that in a water-repellent member having a water-repellent coating film formed on its surface, a layer containing photocatalyst particles and an electron-capturing metal is formed as a base layer of the water-repellent coating film. Water repellent members are described.

[0006] On the other hand, amorphous titanium peroxide sols and amorphous titanium oxide sols having no photocatalytic ability, and titanium oxide sols obtained by heating these sols at 100 ° C or higher are also known. For example, JP-A-9-71418 describes a titania film formed from an amorphous titanium peroxide sol, and JP-A-9-262481 by the present inventors discloses that a photocatalyst is supported and fixed on a substrate. JP-A-10-53437 discloses a method for producing a photocatalyst, which comprises using a titanium oxide sol having photocatalytic ability and an amorphous titanium peroxide sol having no photocatalytic ability. A method for fixing the amorphous titanium peroxide layer is described.

[0007]

As described above, a water-repellent member having both a water-repellent function and a photocatalytic function on its surface is known. However, in the water-repellent member described in JP-A-9-228073, Since the surface was provided with a water-repellent layer and a photocatalytic functional layer containing photocatalyst particles and an electron-capturing metal as an underlayer, it was not sufficient in terms of photocatalytic function. In the case of a porous and water-absorbing base material such as concrete or rock, the deterioration of the base material and the deterioration of the cosmetic property due to the secular change such as dirt such as oil and algae generation on the surface due to infiltration of rainwater or the like are caused. There were problems such as occurrence.

It is an object of the present invention to provide not only an anti-fouling action and an anti-dew action, but also a water-repellent coating film made of an organic polymer resin, which has both excellent water repellent function and excellent photocatalytic function on its surface. Even so, an object of the present invention is to provide a surface water-repellent substrate which is not affected by a photocatalytic layer.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, a specific photocatalyst, that is, an amorphous titanium peroxide sol having no photocatalytic ability was formed on the surface of a substrate subjected to a water-repellent treatment. A water-repellent substrate provided with a photocatalyst layer using an anatase-type titanium oxide sol having photocatalytic ability obtained by heating
The inventors have found that they have not only excellent photocatalytic performance but also excellent water repellency, and have completed the present invention.

In addition, a water-repellent coating film which is deteriorated by a photocatalyst such as an organic polymer resin is formed on the surface of the substrate,
An anatase-type titanium oxide sol obtained by providing a coating layer using an alkali metal silica compound and / or an amorphous titanium oxide sol or an amorphous titanium oxide sol, and further heating the amorphous titanium peroxide sol at 100 ° C. or higher. The water-repellent substrate provided with the photocatalyst layer using the PTFE has not only excellent photocatalytic ability, but also the water-repellent coating film made of an organic polymer resin is not affected by the photocatalytic coating layer and has excellent repellency over a long period of time. They have found that water performance can be maintained, and have completed the present invention.

That is, the present invention relates to a coating film using an alkali metal silica compound or an amorphous titanium oxide sol, an amorphous titanium oxide sol or an amorphous titanium hydroxide containing the alkali metal silica compound on the surface of a substrate. Is formed, and an amorphous titanium peroxide sol is coated on the water-repellent coating film for 10 minutes.
The present invention relates to a water-repellent substrate provided with a photocatalyst layer using an anatase type titanium oxide sol obtained by heating at 0 ° C. or higher.

Further, according to the present invention, a water-repellent coating film is formed on a surface of a substrate, and a coating layer using an amorphous titanium peroxide sol or an amorphous titanium oxide sol is provided on the water-repellent coating film. The present invention relates to a water-repellent substrate characterized in that a photocatalytic layer using an anatase-type titanium oxide sol obtained by heating an amorphous-type titanium peroxide sol at 100 ° C. or higher is provided on the coating layer.

The present invention also provides a water-repellent coating film formed on a surface of a substrate, on which an alkali metal silica compound or an amorphous titanium peroxide sol containing the alkali metal silica compound is provided. A coating layer using an amorphous titanium oxide sol or an amorphous titanium hydroxide is provided. On the coating layer, an anatase type titanium oxide sol obtained by heating the amorphous titanium peroxide sol at 100 ° C. or more was used. The present invention relates to a water-repellent substrate provided with a photocatalyst layer.

Further, according to the present invention, an amorphous titanium peroxide sol or a coating layer using an amorphous titanium oxide sol is provided on the surface of a substrate, and the amorphous titanium peroxide sol is heated to 100 ° C. on the coating layer.
A water repellent comprising an anatase-type titanium oxide sol obtained by heating as described above, an alkali metal silica compound or an amorphous titanium peroxide sol containing the alkali metal silica compound, an amorphous titanium oxide sol or an amorphous titanium hydroxide, or the like. The present invention relates to a water-repellent substrate provided with a photocatalyst layer using the above.

Further, the present invention provides an anatase type obtained by heating an alkali metal silica compound, an amorphous titanium peroxide sol or an amorphous titanium oxide sol, and an amorphous titanium peroxide sol on a surface of a substrate at 100 ° C. or more. The present invention relates to a water-repellent substrate provided with a photocatalyst layer using titanium oxide sol.

Further, in the present invention, the water-repellent substrate, wherein the contact angle of water on the surface is 80 ° or more and the surface tension is 70 dyne / cm or less, or the substrate is inorganic and has pores The present invention relates to the above water-repellent substrate, which is a substrate, particularly a cement or concrete substrate, or a porous rock-based substrate such as sandstone.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The substrate used in the surface water-repellent substrate of the present invention includes cement moldings, building materials such as metal tiles, civil engineering and buildings such as concrete, glass products such as eyeglasses and optical lenses, and the like. Synthetic resin products such as synthetic resin plates, plastic sheets, and fibers can be exemplified. Examples of the material include cement, porous rocks such as sandstone, ceramics, inorganic materials such as glass, organic polymer resins, rubber, and the like. Organic materials such as wood and paper, as well as aluminum,
Metal materials such as steel can be used without any limitation. The size and shape of the substrate are not particularly limited, and may be block-shaped, plate-shaped, needle-shaped, honeycomb-shaped, fiber-shaped, filter-sheet-shaped, bead-shaped, foamed, or a stack of these.

[0018] Among these substrates, inorganic and porous substrates such as cement, concrete, GRC
(Cement hollow extruded material), mortar, tile, brick,
This book is based on porous rocks such as sandstone and uses an alkali metal silica compound or an amorphous titanium oxide sol, an amorphous titanium oxide sol or an amorphous titanium hydroxide containing the alkali metal silica compound as a water repellent. The water-repellent substrate of the present invention, in addition to excellent water-repellent performance and excellent photocatalytic ability, has a strong durable water-absorbing layer formed on the surface of the substrate, resulting in salt damage, frost damage, neutralization, etc. It has an excellent effect on preventing deterioration and the generation of algae.

When the substrate is made of an organic polymer resin material such as a plastic plate and may be deteriorated by the photocatalyst layer, an alkali is placed between the photocatalyst layer and the organic polymer resin-based substrate. Coating layer using metal silica compound solution, amorphous titanium peroxide sol containing this alkali metal silica compound, coating layer using amorphous titanium oxide sol or amorphous titanium hydroxide, or amorphous titanium peroxide sol or amorphous type By interposing a coating layer using a titanium oxide sol as an intermediate layer, or as a photocatalytic layer, a photocatalytic layer containing an alkali metal silica compound, an amorphous titanium peroxide sol or an amorphous titanium oxide sol, and an anatase titanium oxide sol. Establishment By, it is possible to prevent the deterioration due to photocatalytic of the organic polymeric resin substrate. Thus, according to the present invention, the use of the organic polymer resin-based substrate is not restricted as compared with the conventional water-repellent substrate.

The water-repellent coating film of the present invention includes, in addition to a coating layer formed on the surface of a substrate using a water-repellent agent, one having a water-repellent surface itself or a water-repellent agent on the substrate surface. And those exhibiting water repellency due to a chemical reaction on the substrate surface are also included for convenience. Examples of the water repellent used for forming the water repellent coating include JP-A-7-2916.
No. 67, JP-A-8-143332, JP-A-8-143
As long as they exhibit water repellency or hydrophobicity when coated on a substrate, such as those known in the art, such as those disclosed in JP-A-12292 and JP-A-9-228073, and those which are commercially available, inorganic materials Any type of water-repellent (hydrophobic) agent can be used regardless of whether it is a water-based or organic water-repellent agent. What can be done is desirable.

As an organic water repellent, for example, an organic polymer water repellent, a silicon-based or fluorine-based water repellent which generates a water repellent function by heat treatment or bonding with CO ₂ in the air is mentioned. As a silane / silicone water repellent, a methyl-substituted linear dimethylpolysiloxane or a copolymer of dimethylpolysiloxane and methylhydroxysiloxane is used. As a fluorine-based agent, an acrylate containing a perfluoroalkyl group is used. Specific examples thereof include a perfluorooctyl acrylate polymer having a polymer as a main component, a chromium coordination compound of a saturated fluorinated monobasic acid, and a polytetrafluoroethylene agent. Also, a silicone surface modifier “X-24-7” manufactured by Shin-Etsu Chemical Co., Ltd.
890 ”.

In the case where a water-repellent coating is formed on the water-repellent substrate of the present invention using these organic polymer-based water-repellents, the water-repellent coating between the organic polymer-based water-repellent coating and the photocatalyst layer may be used. A coating layer using an alkali metal silica compound solution, an amorphous titanium peroxide sol containing the alkali metal silica compound, a coating layer using an amorphous titanium oxide sol or amorphous titanium hydroxide, or an amorphous titanium peroxide sol Alternatively, it is preferable to prevent the decomposition and deterioration of the organic polymer-based water-repellent coating film by a photocatalyst by interposing a coating layer using an amorphous titanium oxide sol as an intermediate layer. This intermediate layer blocks the photocatalytic action, but does not block the water repellent action.

As the inorganic water repellent, potassium silicate,
Examples thereof include a solution of an alkali metal silica compound such as lithium silicate and sodium silicate, or an amorphous titanium peroxide sol, an amorphous titanium oxide sol, or an amorphous titanium hydroxide compound containing these alkali metal silica compounds. 9-259
No. 495). When an inorganic water repellent comprising these alkali metal silica compound solutions or an inorganic water repellent containing the same is applied to a cement or concrete base material or a porous rock base material such as sandstone, a cement or concrete base material is obtained. Alternatively, the water repellent penetrates into the pores of the porous surface of porous rock such as sandstone and reacts with calcium hydroxide Ca (OH) ₂ which is a lime component in concrete, rock and the like, and reacts with calcium silicate CaSiO _Two layers, a potassium carbonate K ₂ CO ₃ layer by reacting with carbon dioxide in the air, and a layer composed of such calcium silicate and potassium carbonate are formed, and a water-repellent coating film excellent in water resistance is formed. It will be. As a commercially available inorganic water repellent, “Hydrosome RX” manufactured by Nippon Chemics Co., Ltd. can be specifically exemplified. And, when using these inorganic water repellents, unlike the case of using the organic polymer water repellents, an amorphous titanium peroxide sol or an amorphous titanium oxide sol is provided between the water-repellent coating film and the photocatalytic layer. There is no need to provide an intermediate layer.

The above-mentioned alkali metal silica compounds such as potassium silicate, lithium silicate and sodium silicate act to prevent decomposition and deterioration of the organic polymer material such as the organic polymer water-repellent coating film by a photocatalyst. In addition, since it has the effect of enhancing the water repellency of other water repellents, the coating layer containing the alkali metal silica compound, an organic polymer-based water-repellent coating or an organic polymer-based substrate, By interposing it as an intermediate layer with the photocatalyst layer, while preventing decomposition and deterioration of the organic polymer material by the photocatalyst,
A water-repellent substrate having excellent water-repellency can be obtained.

The amorphous titanium oxide sol and the amorphous titanium oxide sol of the present invention do not have a photocatalytic function, but have an ultraviolet absorbing function. In contrast, anatase-type titanium oxide sol has a photocatalytic function. These amorphous titanium peroxide sol, amorphous titanium oxide sol and anatase titanium oxide sol can be produced, for example, as follows.

Aqueous ammonia or an alkali hydroxide such as sodium hydroxide is added to a titanium salt aqueous solution such as titanium tetrachloride TiCl ₄ . The resulting pale bluish white, amorphous titanium hydroxide Ti (OH) ₄ is orthotitanic acid H ₄ Ti
Also called O ₄ , this titanium hydroxide is washed and separated, and then treated with a hydrogen peroxide solution to obtain an amorphous titanium peroxide solution. The amorphous titanium peroxide sol has a pH of 6.0 to 7.0, a particle size of 8 to 20 nm, and is a yellow transparent liquid, and is stable even when stored at room temperature for a long time. The sol concentration is usually 1.40 to
The concentration is adjusted to 1.60%, but the concentration can be adjusted as needed. When used at a low concentration, dilute with distilled water or the like before use. Further, when this amorphous titanium oxide sol is heated at room temperature to 100 ° C., a part of the sol changes into amorphous titanium oxide sol,
When heated as described above, it gradually becomes an anatase type titanium oxide sol.

As described above, the amorphous type titanium oxide sol is obtained by converting the amorphous type titanium peroxide sol as it is
In addition to being obtained by heating at 100 ° C., the substrate is coated with an amorphous titanium peroxide sol at 200 ° C.
It can also be obtained by heating to a certain degree and drying and fixing. Examples of the amorphous titanium hydroxide used in the present invention include an amorphous titanium hydroxide solution which is an intermediate product in the above-mentioned production process of the amorphous titanium peroxide sol.

The amorphous titanium oxide sol and the amorphous titanium oxide sol are not yet crystallized in an amorphous state at room temperature, are excellent in adhesion, have high film-forming properties, and can form a uniform and flat thin film. Can,
In addition, since the dried film has a property of being insoluble in water, the use of these makes it possible to easily form a coating layer at room temperature. As described above, the coating layer using the amorphous titanium oxide sol or the amorphous titanium oxide sol is used to decompose and degrade the adjacent organic polymer resin base material and the organic polymer water-repellent coating film by the photocatalyst. In addition to having the action of preventing water repellency, the water repellent coating formed as a lower layer can exhibit water repellency on the surface of the coating layer without hindering the performance. Further, the coating layer using a mixture of the amorphous titanium oxide sol or the amorphous titanium oxide sol, the alkali metal silica compound, and the anatase titanium oxide sol is used to decompose the adjacent lower organic polymer resin base material by photocatalysis. In addition to having the effect of preventing deterioration, it exhibits excellent water repellency and photocatalytic ability on its surface.

In the present invention, the anatase type titanium oxide sol used for forming the photocatalyst layer can be prepared by heating the amorphous type titanium peroxide sol at 100 ° C. or higher. As described above, when the amorphous titanium peroxide sol is heated at room temperature to 100 ° C., a part thereof is changed to the amorphous titanium oxide sol,
Since heating to the above gradually turns into an anatase-type titanium oxide sol, for example, even when the amorphous-type titanium peroxide sol is heated at 100 ° C. or higher, when the heating is performed only for a short time, etc. Does not become an anatase-type titanium oxide sol, and a mixture of an anatase-type titanium oxide sol and an amorphous-type titanium peroxide sol and / or an amorphous-type titanium oxide sol is generated. Since this mixture also has a photocatalytic activity, the “anatase-type titanium oxide sol obtained by heating the amorphous-type titanium peroxide sol at 100 ° C. or more” in the present invention includes, for convenience, an anatase-type titanium oxide sol and an amorphous-type titanium peroxide sol. And / or a mixture with an amorphous titanium oxide sol. As described above, the type and properties of the product vary depending on the heating temperature and the heating time of the amorphous titanium peroxide sol. However, when the product is treated at, for example, 100 ° C. for 6 hours, most of the product becomes an anatase-type titanium oxide sol. The properties of the anatase-type titanium oxide sol have a pH of 7.5 to 9.5 and a particle size of 8 to
20 nm and its appearance is a yellow suspension liquid. The sol concentration of this anatase type titanium oxide sol is usually 2.7.
The concentration is adjusted to 0 to 2.90% by weight, but the concentration can be adjusted and used as needed. The anatase-type titanium oxide sol is obtained by coating an amorphous titanium peroxide sol on a base material and then drying and fixing the same.
It can also be heated to about 0 ° C. or more to obtain anatase type titanium oxide.

The major feature of the present invention is to use this anatase type titanium oxide sol. By using this anatase-type titanium oxide sol for forming the photocatalyst layer, the water-repellent performance of the water-repellent coating film or the like formed as the lower layer is exhibited on the surface of the water-repellent substrate without being hindered by the photocatalyst layer. In the present invention, other photocatalysts and electron trapping metals can be contained in the anatase-type titanium oxide sol as long as the properties of the anatase-type titanium oxide sol are not impaired. This anatase-type titanium oxide sol has excellent adhesion, high film-forming properties, can produce a uniform and flat thin film, and has the property that the dried film is insoluble in water. It can be easily formed, and 200 to 30
Since heating at 0 ° C is not required, not only does water-repellent performance of the water-repellent coating film decrease due to heating, but also existing building materials with porous rock surfaces such as cement, concrete surfaces, and sandstone. It can also be applied directly to the exterior of civil engineering, buildings, monuments, etc.

In the present invention, as a method of forming a water-repellent coating film and a method of coating an amorphous titanium peroxide sol or an anatase titanium oxide sol, a method of forming a thin film by a method such as spray coating, dipping, or spin coating. No. The thickness of the coating layer is determined by the thickness at which the function of each layer can be achieved, such as imparting water repellency, blocking photocatalytic ability, and developing photocatalytic ability, and the film forming performance of each coating agent.

FIG. 1 is a schematic view of the structure of the water-repellent substrate of the present invention.
6, the present invention is not limited by this. In FIG. 1, a water-repellent coating film 2 using an alkali metal silica compound solution is provided on the surface of an inorganic base material 1, and a photocatalyst layer 3 using an anatase type titanium oxide sol is provided on the surface of the water-repellent coating film 2. The provided water repellent substrate of the present invention is shown. In FIG. 2, an organic polymer-based water repellent coating 4 is provided on the surface of the inorganic base material 1, and a coating layer 5 using an amorphous titanium peroxide sol is provided on the water-repellent coating 4. The water-repellent substrate of the present invention in which a photocatalyst layer 3 using an anatase type titanium oxide sol is provided on the upper surface of the coating layer 5 is shown. In FIG. 3, an organic polymer-based water-repellent coating film 4 is provided on the surface of the inorganic base material 1,
A coating layer 2 using an alkali metal silica compound solution is provided on the water-repellent coating film 4, and a photocatalytic layer 3 using an anatase type titanium oxide sol is provided on the upper surface of the coating layer 2. A water repellent substrate is shown.

In FIG. 4, an organic polymer-based water-repellent coating 4 is provided on the surface of the inorganic base material 1, and the water-repellent coating 4 is coated on an amorphous type coating containing an alkali metal silica compound. The water-repellent substrate of the present invention in which a coating layer 6 using a titanium oxide sol is provided, and a photocatalytic layer 3 using an anatase-type titanium oxide sol is provided on the upper surface of the coating layer 6 is shown. In FIG. 5, a coating layer 5 using an amorphous titanium peroxide sol is provided on the surface of an organic polymer resin base material 7, and the coating layer 5 is formed of an anatase titanium oxide sol and an alkali metal silica compound. A water-repellent substrate of the present invention provided with a photocatalyst layer 8 using a water-repellent is shown. FIG. 6 shows a water-repellent substrate of the present invention in which a photocatalyst layer 9 using an alkali metal silica compound, an amorphous titanium peroxide sol and an anatase titanium oxide sol is provided on the surface of an organic polymer resin substrate 7. Have been.

The surface water-repellent substrate having a photocatalyst layer of the present invention has excellent water repellency (hydrophobic) performance when irradiated with ultraviolet light and an antifouling function using a photocatalyst, and exhibits the antifouling function using a photocatalyst when not irradiated with ultraviolet light. It has the characteristic of having excellent water repellency although it cannot be obtained. In the case of the water-repellent substrate of the present invention, the function of blocking deterioration due to the photocatalytic function is provided between the photocatalytic layer having photocatalytic ability and the organic polymer resin water-repellent coating film or organic polymer resin substrate. Coating layer containing an amorphous titanium oxide sol and / or an amorphous titanium oxide sol, a coating layer using an alkali metal silica compound solution, an amorphous titanium peroxide sol containing an alkali metal silica compound, and an amorphous titanium oxide sol Or because there is a coating layer using amorphous titanium hydroxide, the above-mentioned organic polymer resin water-repellent coating film and organic polymer resin base material do not deteriorate, and excellent water repellency and antifouling function are maintained for a long time. Is maintained over

As described above, the excellent water-repellent (hydrophobic) performance of the water-repellent substrate of the present invention is such that the water-repellent performance of the lower layer is expressed on the surface through the photocatalytic layer or the water-repellent is mixed with the photocatalytic layer. When it is present, it appears on the surface of the photocatalytic layer and does not attract rainwater or the like, but does not have an oil-repellent effect on oil or the like. It is said that such water repellency and oil repellency are determined by the strength of the interaction between the solid and the liquid, that is, the magnitude of the solid / liquid interfacial tension. When r) is large (rc <r), the substrate surface exhibits water repellency and oil repellency. For example, a substrate treated with an alkali metal silicate compound water repellent, a paraffin water repellent, or a silicon water repellent having a critical surface tension (rc) of about 24 to 26 dyne / cm has a surface tension of 72 dyne / cm2.
It has a water-repellent effect on water of cm or rainwater of 53 dyne / cm, but has no oil-repellent effect on gasoline or the like having a surface tension of 22 dyne / cm. May cause dirt. In addition, the oil film adhered to the surface of the rain water droplets slightly remains when the water droplets are removed from the water-repellent substrate, and the accumulation of the oil film also causes contamination,
Since the water-repellent substrate of the present invention has a photocatalytic function as well as water-repellent performance, it can decompose contaminant organic substances such as oil and scale attached to the surface of the substrate by the photocatalytic action.

When a solid, a liquid and its saturated vapor are brought into contact with each other, the contact angle defined as the angle on the side containing the liquid out of the angle between the tangent drawn on the liquid at the three-phase contact point and the solid surface also becomes Similarly to the critical surface tension of the above-mentioned substrate, it is usually used as a criterion for expressing the water-repellent performance of a water-repellent substrate. The water repellent substrate of the present invention desirably has a water contact angle of 80 ° or more, preferably 90 ° or more, and a surface tension of 70 dyne / cm or less, preferably 50 dyne / cm or less.

[0037]

EXAMPLES The present invention will be described more specifically below with reference to examples, but the technical scope of the present invention is not limited to these examples. Reference Example 1 (Production of Amorphous Titanium Peroxide Sol) A 50% solution of titanium tetrachloride TiCl ₄ (Sumitomo Sytics Co., Ltd.) diluted 70 times with distilled water and a 25% solution of ammonium hydroxide NH ₄ OH ( Takasugi Pharmaceutical Co., Ltd.) diluted 10-fold with distilled water and a volume ratio of 7:
1 and perform a neutralization reaction. After the neutralization reaction, the pH was 6.5.
Adjust to 6.8, leave for a while and discard the supernatant. Distilled water about 4 times the gel amount of the remaining Ti (OH) ₄ is added, and the mixture is sufficiently stirred and left. Check with silver chloride and repeat washing with water until chloride ions in the supernatant are no longer detected. Finally, discard the supernatant and leave only the gel. In some cases, dehydration treatment can be performed by centrifugation. To 3600 ml of this pale bluish white Ti (OH) ₄ , 210 ml of 35% hydrogen peroxide solution is added in two portions every 30 minutes, and the mixture is stirred at about 5 ° C. overnight, and about 2500 ml of a yellow transparent amorphous titanium peroxide sol is obtained. Is obtained. In addition, in the above steps, if the heat generation is not suppressed, a substance insoluble in water such as metatitanic acid may be precipitated. Therefore, it is preferable that all the steps be performed with the heat generation suppressed.

REFERENCE EXAMPLE 2 (Production of anatase-type titanium oxide sol) When the above amorphous titanium peroxide sol is heated at 100 ° C., anatase-type titanium oxide sol is formed after about 3 hours, and when heated for about 6 hours, anatase-type titanium oxide sol is obtained. Can be When heated at 100 ° C. for 8 hours, it takes on a slightly yellow fluorescent color, and when it is concentrated, an opaque yellow one is obtained. When heated at 100 ° C. for 16 hours, a very pale yellow one is obtained. The degree of dry adhesion is slightly lower than that obtained by heating at 100 ° C. for 6 hours. This anatase type titanium oxide sol has a lower viscosity than amorphous type titanium peroxide, so that it can be concentrated to about 2.5% by weight so as to be easily dipped and used.

(Preparation of Water-Repellent Substrate) Example 1 0.05 g of a water-repellent containing 7.4% by weight of potassium silicate was uniformly applied on a surface of a 100 × 100 × 2 mm glass plate, and then heated at 100 ° C. After drying, the anatase type titanium oxide sol (TiO ₂
0.4 g of a two-fold dilution of 1.7% by weight)
Was uniformly applied and dried at 28 ° C. to prepare a water-repellent substrate of the present invention. The coating was performed with a diameter of 0.5 from Meiji Kikai Co., Ltd.
Spray gun FS with 4 mm round blowing nozzle
-G05R-1 was used at an air pressure of 2 kg / cm ³ (the same applies hereinafter).

Example 2 0.4 g of a silicone surface modifier "X-24-7890" manufactured by Shin-Etsu Chemical Co., Ltd. was uniformly applied on the surface of the above-mentioned glass plate, dried at 28 ° C., and then placed thereon. The amorphous titanium peroxide sol prepared in Reference Example 1 (containing 1.7% by weight as TiO ₃ ), diluted twice, was uniformly coated with 0.2 g, dried at 28 ° C., and further dried thereon. 0.4 g of a two-fold dilution of titanium oxide sol (containing 1.7% by weight as TiO ₂ ) was uniformly applied, and 28
It dried at ℃, and prepared the water-repellent substrate of the present invention.

Comparative Examples 1 and 2 0.4 g of a two-fold dilution of the anatase-type titanium oxide sol (containing 1.7% by weight as TiO ₂ ) was uniformly applied on the surface of the glass plate, and dried at 28 ° C. After that, 0.05 g and 0.1 g of a water repellent containing 7.4% by weight of the above potassium silicate were uniformly applied thereon, respectively.
After drying at 100 ° C., the water-repellent substrates of Comparative Examples 1 and 2 were prepared.

Example 3 0.9 g of a water repellent containing 7.4% by weight of potassium silicate was uniformly applied to the surface of a 300.times.300.times.10 mm GRC (hollow cement extrusion molded material: manufactured by Showa Denko KK). And dried at 28 ° C., and then the above-mentioned anatase type titanium oxide sol (containing 1.7% by weight as TiO ₂ )
0.6 g of the double dilution was uniformly applied and dried at 28 ° C. to prepare a water-repellent substrate of the present invention.

Example 4 On a surface of a 300 × 300 × 24 mm Indian sandstone (for wall) building material, a water repellent containing 7.4% by weight of the above-mentioned potassium silicate was added at 1.2 g / 10.
The solution was uniformly coated at a rate of 0 cm ² , dried at 28 ° C., and a 2-fold diluted solution of the anatase-type titanium oxide sol (containing 1.7% by weight as TiO ₂ ) was placed thereon at 0.8 g / 100 c
m ² was applied uniformly and dried at 28 ° C. to prepare a water-repellent substrate of the present invention.

(Water repellency test) On the test substrates prepared in Examples 1 to 4 and Comparative Examples 1 and 2, 0.1% tap water was applied.
ml was dropped from a height of 1 cm with a dropper, left for about 10 minutes, and then measured by measuring the contact angle of a water drop on the substrate. Table 1 shows the results.

(Photocatalytic Performance Test) A 20-fold diluted solution of a commercially available red ink (manufactured by Pilot Corporation) was applied to the test substrates prepared in Examples 1 to 4 and Comparative Examples 1 and 2 by spraying. The time to decolorization on the substrate surface is
It was measured outdoors under climatic conditions of 28 ° C. Table 1 shows the results.

[0046]

[Table 1]

As can be seen from the water repellency test in Table 1, each of the substrates prepared in Examples 1 to 4 and Comparative Examples 1 and 2 had a contact angle exceeding 90 °, and exhibited excellent water repellency. However, in the photocatalytic performance test by the organic substance decomposition reaction using the red ink, the water-repellent substrates of Examples 1 to 3 of the present invention having a photocatalyst layer on the surface layer, a water-repellent coating film on the surface layer The decoloring time of the red ink was as fast as 1/4 as compared with the substrate of Comparative Example, and it was found that the water-repellent substrate of the present invention was remarkably excellent in photocatalytic performance.

[0048]

The water-repellent substrate of the present invention has an extremely excellent water-repellent function and a photocatalytic function, and has both an antifouling action and a dew-proofing action. In addition, the water-repellent substrate of the present invention does not suffer deterioration due to photocatalysis even if the water-repellent coating is made of an organic polymer resin, and even if the substrate is an organic polymer resin substrate, According to the present invention, the use of the organic polymer resin-based material in the water-repellent coating film and the base material is not limited because the polymer polymer is not deteriorated by the use of the organic polymer resin-based material. Further, in the present invention, using a substrate having a pore in an inorganic material such as rocks such as concrete and sandstone as the substrate,
When an alkali metal silica compound or an amorphous titanium peroxide sol containing this alkali metal silica compound is used as a water repellent, in addition to excellent water repellency and excellent photocatalytic ability, the substrate surface has excellent durability. As a result of the formation of a strong water absorption preventing layer, it exhibits excellent effects in preventing deterioration due to salt damage, freezing damage, neutralization and the like, and in preventing generation of algae.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating a water-repellent substrate of the present invention.

FIG. 2 is a schematic view illustrating a water-repellent substrate according to a different embodiment of the present invention.

FIG. 3 is a schematic view illustrating a water-repellent substrate according to a different embodiment of the present invention.

FIG. 4 is a schematic view illustrating a water-repellent substrate according to a different embodiment of the present invention.

FIG. 5 is a schematic view illustrating a water-repellent substrate according to another embodiment of the present invention.

FIG. 6 is a schematic view illustrating a water-repellent substrate according to a different embodiment of the present invention.

[Brief description of reference numerals]

Reference Signs List 1 inorganic base material 2 water-repellent coating or coating layer using alkali metal silica compound solution 3 photocatalytic layer using anatase-type titanium oxide sol 4 organic polymer-based water-repellent coating 5 coating using amorphous titanium peroxide sol Layer 6 Coating layer using amorphous titanium oxide sol containing alkali metal silica compound 7 Organic polymer resin base material 8 Photocatalytic layer using water repellent composed of anatase type titanium oxide sol and alkali metal silica compound 9 Amorphous type Photocatalytic layer using titanium oxide sol and anatase type titanium oxide sol

Continued on the front page (72) Inventor Shiro Ogata 1-52-1, Tomigaya, Shibuya-ku, Tokyo KN Building 3F, Tao Co., Ltd. (72) Inventor Shunichi Tanaka 2-9-1-11 Higashi-Nihonbashi, Chuo-ku, Tokyo (72) Inventor Toyohiko Minatoya 3-11-20 Minamikarasuyama 203, Setagaya-ku, Tokyo 203

Claims (10)

[Claims] 1. A water-repellent coating film is formed on a surface of a substrate,
A water-repellent substrate, comprising a photocatalyst layer using an anatase-type titanium oxide sol obtained by heating an amorphous titanium peroxide sol at 100 ° C. or higher on the water-repellent coating film. 2. The water-repellent coating film is a coating film using an alkali metal silica compound or an amorphous titanium peroxide sol, an amorphous titanium oxide sol or an amorphous titanium hydroxide containing the alkali metal silica compound. The water-repellent substrate according to claim 1, wherein: 3. A water-repellent coating film is formed on the surface of the substrate,
On the water-repellent coating film, a coating layer using an amorphous titanium peroxide sol or an amorphous titanium oxide sol is provided, and the amorphous titanium peroxide sol is obtained by heating the amorphous titanium peroxide sol at 100 ° C. or higher. A water-repellent substrate provided with a photocatalyst layer using the anatase-type titanium oxide sol obtained. 4. A water-repellent coating film is formed on a surface of a substrate,
A coating layer using an alkali metal silica compound or an amorphous titanium oxide sol, an amorphous titanium oxide sol or an amorphous titanium hydroxide containing the alkali metal silica compound is provided on the water-repellent coating film. A water-repellent substrate, wherein a photocatalytic layer using an anatase type titanium oxide sol obtained by heating an amorphous type titanium peroxide sol at 100 ° C. or higher is provided on the layer. 5. A method in which an amorphous titanium peroxide sol or a coating layer using an amorphous titanium oxide sol is provided on a surface of a substrate, and the amorphous titanium peroxide sol is heated at 100 ° C. or higher on the coating layer. A water-repellent substrate provided with a photocatalyst layer using an anatase-type titanium oxide sol obtained by the above method and a water-repellent agent. 6. The water-repellent agent is an alkali metal silica compound or an amorphous titanium peroxide sol, an amorphous titanium oxide sol or an amorphous titanium hydroxide containing the alkali metal silica compound. The water-repellent substrate as described above. 7. An alkali metal silica compound, an amorphous titanium oxide sol or an amorphous titanium oxide sol, and an anatase type titanium oxide sol obtained by heating the amorphous titanium peroxide sol at 100 ° C. or higher on a surface of a substrate. A water-repellent substrate, comprising a photocatalyst layer using the same. 8. The water-repellent substrate according to claim 1, wherein the contact angle of water on the surface is 80 ° or more, and the critical surface tension is 70 dyne / cm or less. 9. The water-repellent substrate according to claim 1, wherein the substrate is an inorganic substrate having pores. 10. The water-repellent substrate according to claim 9, wherein the inorganic substrate having pores is a cement or concrete substrate, or a porous rock-based substrate.