JPH10212809A - Building material for external wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the water-repellent property of a surface and prevent the surface from getting dirty, by forming a surface layer containing photocatalyst particles, water-repellent silicone, and a substance preventing the water-repellent silicone from getting hydrophilic owing to the photoexcitation of the photocatalyst, on a base material surface. SOLUTION: A surface layer containing photocatalyst particles such as anatase type titanium oxide, zinc oxide, tin oxide, water-repellent silicone, a substance such as cobalt or cobalt compounds preventing the water-repellent silicone from getting hydrophilic owing to the photoexcitation of the photocatalyst, is formed on the base material surface of a building material for an external wall such as glazed tiles, non-glazed tiles, bricks. Cobalt alloy, cobalt oxide, etc., are favorable for cobalt compounds and the film thickness of the surface layer is favorably made 0.4μm or thinner. In this way, white turbidity resulting from diffuse reflection of light can be prevented and the surface layer becomes substantially transparent. And further, color development of the surface layer resulting from interference of light can be prevented by making the film thickness 0.2μm or thinner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to dirt from combustion products such as dust and exhaust gas, dirt eluted from a sealant located above, dirt emitted from an exhaust port of a building, and the like. The present invention relates to antifouling exterior wall building materials.

[0002]

2. Description of the Related Art The outer walls of high-rise buildings, houses, and the like are stained by combustion products such as dust and exhaust gas, stains eluted from a sealant located above, and pollutants discharged from a building exhaust port. Get dirty. These stains are dark and significantly impair the aesthetics of the building. Further cleaning of high-rise building outer walls is a high-altitude operation, not only a heavy task but also a risk.

[0003]

Therefore, there is a need for a building material for an outer wall that is less likely to be soiled.

As a method for preventing the adhesion of dirt, it is known that it is better to impart water repellency to the surface of a substrate. When water repellency is imparted to the surface of the base material, the surface energy is significantly reduced, so that it becomes difficult for dirt components to adhere. As one of the methods, there is a method of forming a surface layer made of a water-repellent silicone on a substrate surface. However, with this structure, the contact angle with water is reduced to about 70 ° due to the adhesion of dirt over time, and the effect of water repellency is not maintained. Therefore, as another method for solving the above-mentioned problem, there is a method of forming a surface layer comprising a photocatalyst and a water-repellent silicone on the surface of a substrate. According to this method, it is possible to decompose the adhered dirt over time based on the oxidative decomposability of the photocatalyst. However, in this configuration, when exposed to sunlight outdoors, the silicone is hydrophilized by photoexcitation of the photocatalyst, so that the water repellency of the surface cannot be maintained. In view of the above circumstances, an object of the present invention is to provide a building material for an outer wall that can maintain the water repellency of the surface for a long period of time, and to provide a building material for an outer wall that is less likely to be soiled.

[0005]

According to the present invention, in order to solve the above-mentioned problems, photocatalytic particles, water-repellent silicone, and hydrophilicity of the water-repellent silicone by photoexcitation of the photocatalyst are provided on a substrate surface. Or a layer containing photocatalyst particles and a water-repellent silicone is formed on the surface of the base material, and is further formed on at least a part of the surface of the layer. The present invention provides a building material for an outer wall, wherein a substance for preventing the water-repellent silicone from becoming hydrophilic by photoexcitation of the photocatalyst is fixed.
Preventing the silicon from becoming hydrophilic by photoexcitation of the photocatalyst by making the surface layer contain a substance such as cobalt or a cobalt compound for preventing the photocatalyst from becoming hydrophilic by photoexcitation. Can be.
In addition, since the photocatalyst is contained, it is possible to decompose the dirt adhering with time based on the oxidative decomposability of the photocatalyst. Therefore, the water repellency of the surface can be maintained, and the building material for the outer wall can be maintained in a permanently hardly soiled state.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In one embodiment of the present invention,
As shown in FIG. 1, a surface layer containing photocatalyst particles, silicone, and a substance for preventing photocatalyst such as cobalt or a cobalt compound from becoming hydrophilic by photoexcitation is formed on the surface of the building material for the outer wall. . In another embodiment of the present invention, as shown in FIG. 2, a layer containing photocatalyst particles and a water-repellent silicone is formed on the surface of the building material for an outer wall, and at least a part of the surface of the layer is formed on the surface. A substance for preventing hydrophilicity by photoexcitation of a photocatalyst of water-repellent silicone such as cobalt or a cobalt compound is fixed. The base materials for building materials for exterior walls include well-known building materials such as glazed tiles, unglazed tiles, bricks, crystallized glass, glass blocks, concrete, stone, wood, lightweight cellular concrete, asbestos cement calcium silicate, Precast reinforced concrete
Inorganic base materials such as gypsum, asbestos slates, pulp cement, and gypsum boards; and a resin coating such as an acrylic resin, a urethane resin, a polyester, a silicone, a fluororesin, and an acrylic silicon resin is applied to the surface layer. Decorative inorganic building materials;
Metallic base material such as aluminum, stainless steel, steel and the like, and a coated steel plate material coated on its surface with a resin paint such as acrylic resin, urethane resin, polyester, silicone, fluorine resin, acrylic silicon resin; polycarbonate
And acrylic or other plastics or their coated plates can be suitably used. A corrosion-resistant intermediate layer may be provided between the substrate and the surface layer. As the material of the corrosion-resistant intermediate layer, silicone resin, amorphous silica, acrylic silicon resin and the like can be suitably used.

A photocatalyst has an energy greater than the energy gap between the conduction band and the valence band of the crystal.
A substance capable of generating conduction electrons and holes by excitation of electrons in the valence band (photoexcitation) when irradiated with light (excitation light) having a short wavelength (excitation light).
Oxides such as zeta-type titanium oxide, zinc oxide, tin oxide, ferric oxide, bismuth trioxide, tungsten trioxide and strontium titanate can be suitably used. As the light source used for photoexcitation of the photocatalyst is exposed to the sun during the day, sunlight can be used.

The silicone has an average composition formula R _p SiO _{(4-p) / 2} (where R is a functional group comprising one or more monovalent organic groups, or a monovalent organic group) A resin represented by the following formula: X is an alkoxy group or a halogen atom, and p is a number satisfying 0 <p <2. Is available.

As the cobalt compound, cobalt alloy, cobalt oxide, cobalt chloride, cobalt sulfate, cobalt iodide, cobalt bromide, cobalt acetate, cobalt chlorate, cobalt nitrate and the like can be suitably used.

The thickness of the surface layer is preferably set to 0.4 μm or less. Then, cloudiness due to irregular reflection of light can be prevented, and the surface layer becomes substantially transparent. More preferably, the thickness of the surface layer is 0.2 μm or less. Then, it is possible to prevent the surface layer from being colored by light interference. Also, the thinner the surface layer, the better its transparency. Further, when the film thickness is reduced, the wear resistance of the surface layer is improved.

A metal such as Ag, Cu and Zn can be added to the surface layer. The surface layer to which the metal is added can kill bacteria and fungi attached to the surface even in a dark place.

Pt, Pd, Ru, Rh, I
A platinum group metal such as r or Os can be added.
The surface layer to which the metal is added can enhance the redox activity of the photocatalyst, and can improve the decomposability of organic contaminants and the decomposability of harmful gases and odors.

Next, a surface layer containing photocatalyst particles, water-repellent silicone, and a substance for preventing the water-repellent silicone from becoming hydrophilic by photoexcitation of the photocatalyst is formed on the surface of the substrate. The method of manufacturing the water-repellent member described above will be described. The production method in this case is basically based on applying a coating composition on the surface of a substrate and curing the coating composition.

Here, the coating composition contains a precursor of silicon as an essential component of a substance for preventing photocatalytic particles, cobalt or a cobalt compound or the like from becoming hydrophilic by photoexcitation of a photocatalyst. Solvents such as ethanol and propanol, catalysts that promote hydrolysis of silicone precursors such as hydrochloric acid, nitric acid, sulfuric acid, acetic acid and maleic acid, and basic compounds such as tributylamine and hexylamine Silicon compounds such as acidic compounds such as aluminum, aluminum triisopropoxide and tetraisopropyl titanate;
And a surfactant for improving the dispersibility of the coating liquid such as a silane coupling agent.

As cobalt or a cobalt compound, a water-soluble cobalt compound is preferably used. As the water-soluble cobalt compound, for example, cobalt chloride, cobalt sulfate, cobalt iodide, cobalt bromide, cobalt acetate, cobalt chlorate, cobalt nitrate and the like can be suitably used.

[0016] Here silicone - The precursor emissions in the average composition formula _{R p SiX q O (4-} pq) / 2 ( wherein, R consists of one or more organic groups monovalent functional X or a functional group comprising two or more selected from a monovalent organic group and a hydrogen group, X is an alkoxy group or a halogen atom, and p and q are 0 <p <2, 0 <
a film-forming element composed of a siloxane represented by the following formula: q <4) or a general formula R _p SiX _4-p (where R is one or more monovalent organic groups) Wherein X is an alkoxy group or a halogen atom, and p is 1 or 2. A film-forming element comprising a hydrolyzable silane derivative to be
Can be suitably used.

Here, as the coating film forming element comprising the hydrolyzable silane derivative, methyltrimethoxysilane,
Methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltributoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, Phenyltributoxysilane,
Dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldipropoxysilane, diethyldibutoxysilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, phenyl Methyldipropoxysilane, phenylmethyldibutoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltripropoxysilane, n-propyltributoxysilane, γ-glycoxydoxypropyltrimethoxysilane, γ -Acryloxypropyltrimethoxysilane and the like can be suitably used.

The film-forming element composed of the siloxane includes a partial hydrolysis and dehydration-condensation polymerization of the hydrolyzable silane derivative, or a partial hydrolyzate of the hydrolyzable silane derivative, tetramethoxysilane, tetraethoxysilane and tetraethoxysilane. It can be produced by dehydration polycondensation with a partial hydrolyzate such as silane, tetrapropoxysilane, tetrabutoxysilane, diethoxydimethoxysilane and the like.

The coating method of the coating composition includes spray coating, dip coating, flow coating, spin coating, roll coating, brush coating, and sponge. A method such as coating can be suitably used. As a curing method, it can be carried out by polymerizing by heat treatment, standing at room temperature, ultraviolet irradiation, or the like.

Next, a layer containing photocatalyst particles and a water-repellent silicone is formed on the surface of the base material, and at least a part of the surface of the layer is formed by photoexcitation of the photocatalyst by the water-repellent silicone. A method for manufacturing a water-repellent member to which a substance for preventing hydrophilicity is fixed will be described. The production method in this case is basically based on the photo-excitation of a photocatalyst such as cobalt or a cobalt compound after coating and curing a coating composition containing photocatalyst particles and a water-repellent silicone precursor. By applying a solution containing a substance for preventing hydrophilization and fixing the solution to the surface.

Here, the coating composition has photocatalyst particles and a precursor of a water-repellent silicone as essential components, and in addition, a solvent such as water, ethanol, propanol, hydrochloric acid, nitric acid, and the like. Catalysts that promote the hydrolysis of silica precursors such as sulfuric acid, acetic acid and maleic acid, basic compounds such as tributylamine and hexylamine, and acidic compounds such as aluminum triisopropoxide and tetraisopropyl titanate Such as a catalyst for curing a precursor of silica,
A surfactant such as a silane coupling agent for improving the dispersibility of the coating liquid may be added.

[0022] Here silicone - The precursor emissions in the average composition formula _{R p SiX q O (4-} pq) / 2 ( wherein, R consists of one or more organic groups monovalent functional X or a functional group comprising two or more selected from a monovalent organic group and a hydrogen group, X is an alkoxy group or a halogen atom, and p and q are 0 <p <2, 0 <
a film-forming element composed of a siloxane represented by the following formula: q <4) or a general formula R _p SiX _4-p (where R is one or more monovalent organic groups) Wherein X is an alkoxy group or a halogen atom, and p is 1 or 2. A film-forming element comprising a hydrolyzable silane derivative to be
Can be suitably used.

Here, as the coating film forming element comprising the hydrolyzable silane derivative, methyltrimethoxysilane,
Methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltributoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, Phenyltributoxysilane,
Dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldipropoxysilane, diethyldibutoxysilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, phenyl Methyldipropoxysilane, phenylmethyldibutoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltripropoxysilane, n-propyltributoxysilane, γ-glycoxydoxypropyltrimethoxysilane, γ -Acryloxypropyltrimethoxysilane and the like can be suitably used.

The film-forming element composed of the siloxane includes partial hydrolysis and dehydration condensation polymerization of the hydrolyzable silane derivative, or partial hydrolyzate of the hydrolyzable silane derivative, tetramethoxysilane, tetraethoxysilane, and the like. It can be produced by dehydration polycondensation with a partial hydrolyzate such as silane, tetrapropoxysilane, tetrabutoxysilane, diethoxydimethoxysilane and the like.

The coating method of the above coating composition includes spray coating, dip coating, flow coating, spin coating, roll coating, brush coating, and sponge. A method such as coating can be suitably used. As a curing method, it can be carried out by polymerizing by heat treatment, standing at room temperature, ultraviolet irradiation, or the like.

The method of applying a solution containing a substance for preventing the photocatalyst such as cobalt or a cobalt compound from being hydrophilized by photoexcitation and fixing it on the surface includes, for example, cobalt chloride, cobalt sulfate, cobalt iodide, bromide, and the like. cobalt,
Spray coating method, dip coating method, flow coating method, spin coating method, roll coating method, brushing water-soluble cobalt compounds such as cobalt acetate, cobalt chlorate and cobalt nitrate Coating, sponge coating, etc., photoreduction, heat treatment, alcohol
This is performed by fixing by a method such as reduction using a sacrificial oxidizing agent such as toluene.

[0027]

【Example】

Reference example. Anatase type titanium oxide sol (Nissan Chemical, TA
-15, nitric acid peptized type, pH = 1), silica sol (Nippon Synthetic Rubber, Glasca A solution, pH = 4), methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B solution) and ethanol are mixed. The coating liquid obtained by stirring for 2 to 3 hours was applied on a 5 × 10 cm square glazed tile base material (TOTOKIKI, AB02E11) by spray coating.
A heat treatment was performed at 200 ° C. for 15 minutes to obtain a # 1 sample having a surface layer formed of 11 parts by weight of anatase type titanium oxide particles, 6 parts by weight of silica, and 5 parts by weight of silicone. The contact angle of the # 1 sample with water was 92 °. Here, the contact angle with water was evaluated using a contact angle measuring device (Kyowa Interface Science, CA-X150) by the contact angle with water 30 seconds after a water droplet was dropped from the micro syringe. Next, the surface of the # 1 sample was irradiated for one day with an ultraviolet illuminance of 0.3 mW / cm ² using an ultraviolet light source (Sankyo Electric, Black Light Blue (BLB) fluorescent lamp) to obtain a # 2 sample. As a result, the contact angle with water of the # 2 sample was hydrophilized to 0 °. Next, # 1 sample and #
One sample was irradiated with a mercury lamp at an ultraviolet irradiance of 22.8 mW / cm ² for 2 hours, and the surface of each of the # 3 samples obtained was subjected to Raman spectroscopic analysis. As a result, a peak of methyl group observed on the surface of sample # 1 was not observed in sample # 3, but a peak of hydroxyl group was observed instead. From the above,
It can be seen that the organic group bonded to the silicon atom in the silicon molecule on the surface of the film by the photoexcitation of the anatase type titanium oxide which is a photocatalyst is replaced by a hydroxyl group and becomes hydrophilic.

Embodiment 1 FIG. Anatase type titanium oxide sol (Nissan Chemical, TA-15, peptized nitrate, pH = 1),
Silica sol (Nippon Synthetic Rubber, Glasca A solution, pH = 4)
And methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B solution), cobalt chloride hexahydrate, and ethanol, and stirred for 2-3 hours. -Apply on a 5 x 10 cm square glazed tile base material (TOTOKI KIKI, AB02E11) at 200 ° C
And heat-treated for 15 minutes in anatase type titanium oxide particles 11
A # 4 sample was obtained in which a surface layer consisting of 6 parts by weight of silica, 6 parts by weight of silica, 5 parts by weight of silicon, and 0.2 parts by weight of cobalt was formed. The contact angle of the # 4 sample with water was 97 °. Here, the contact angle with water is measured using a contact angle measuring device (Kyowa Interface Science, CA-X).
150), the contact angle with water was evaluated 30 seconds after a water drop was dropped from the micro syringe. Next, an ultraviolet light source (Sankyo Electric, Black Light Blue-
(BLB) fluorescent lamp) for 1 day at an ultraviolet illuminance of 0.3 mW / cm ² to obtain a # 5 sample. As a result, # 5
The contact angle of the sample with water was still 96 °, maintaining water repellency.
Therefore, it can be understood from the above that the hydrophilicity of the silicon on the surface of the coating film due to the photoexcitation of the anatase type titanium oxide as a photocatalyst is inhibited by cobalt. This is considered because the substitution of the hydroxyl group for the organic group bonded to the silicon atom in the silicon molecule on the surface of the coating is inhibited by cobalt.

Embodiment 2 FIG. Anatase type titanium oxide sol (Nissan Chemical, TA-15, peptized nitrate, pH = 1),
Silica sol (Nippon Synthetic Rubber, Glasca A solution, pH = 4)
, Methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B solution) and ethanol were mixed, and the mixture was stirred for 2 to 3 hours to obtain a coating solution by spray coating.
× 10cm square glazed tile base material (TOTOKI, AB02E
11) Coated on top and heat-treated at 200 ° C. for 15 minutes to obtain 11 parts by weight of anatase type titanium oxide particles, 6 parts by weight of silica,
A surface layer consisting of 5 parts by weight of silicone was formed. Further, 0.3 g of an aqueous solution of cobalt chloride hexahydrate having a cobalt metal concentration of 50 μmol / g was applied thereon, and then an ultraviolet illuminance of 0.4 mW / The cobalt was fixed on the substrate by irradiating it with ultraviolet rays of cm ² for 10 minutes to obtain a # 6 sample. #
The contact angle of 6 samples with water was 95 °. Here, the contact angle with water is measured using a contact angle measuring device (Kyowa Interface Science, CA-X15).
0), and after adding a water drop from the micro syringe, 3
Evaluation was made based on the contact angle with water after 0 seconds. Next, an ultraviolet light source (Sankyo Electric, Black Light Blue- (B
(LB) Fluorescent lamp) to irradiate with an ultraviolet illuminance of 0.3 mW / cm ² for 1 day to obtain a # 7 sample. As a result, the contact angle of the # 7 sample with water was still 94 °, maintaining water repellency. Therefore, it can be understood from the above that the hydrophilicity of the silicon on the surface of the coating film due to the photoexcitation of the anatase type titanium oxide as a photocatalyst is inhibited by cobalt. this is,
It is considered that the replacement of the organic group bonded to the silicon atom in the silicon molecule on the surface of the coating film with the hydroxyl group is inhibited by cobalt.

Embodiment 3 FIG. The # 5 sample, the # 7 sample, and a polytetrafluoroethylene plate for comparison were placed under the roofed part of the building as shown in FIG. 3 and left for 4 months. As a result, stains were observed on the polytetrafluoroethylene plate, whereas no stains were observed on the # 5 and # 7 samples.

[0031]

According to the present invention, in a building material for an outer wall, a photocatalyst particle, a water-repellent silicone, and a substance for preventing the water-repellent silicone from becoming hydrophilic by photoexcitation of the photocatalyst are provided on the surface of the base material. Or a layer containing photocatalyst particles and a water-repellent silicone is formed on the surface of the substrate, and at least a part of the surface of the layer has the repellent. By fixing the substance for preventing the hydrophilicity of the aqueous silicone by the photoexcitation of the photocatalyst, the surface of the member can maintain the water repellency for a long period of time, thereby making it hard to be permanently stained.

[Brief description of the drawings]

FIG. 1 is a view showing a surface structure of a building material for an outer wall according to the present invention.

FIG. 2 is a diagram showing another surface structure of a building material for an outer wall according to the present invention.

FIG. 3 is a view showing a method of setting a test sample according to the embodiment of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 83/04 C08L 83/04

Claims (3)

[Claims] 1. A surface layer containing photocatalyst particles, water-repellent silicone, and a substance for preventing the water-repellent silicone from becoming hydrophilic by photoexcitation of the photocatalyst is formed on the surface of a substrate. A building material for an outer wall, characterized in that: 2. A layer containing photocatalyst particles and a water-repellent silicone is formed on the surface of a base material, and at least a part of the surface of the layer is made hydrophilic by the photoexcitation of the photocatalyst of the water-repellent silicone. A building material for an outer wall, wherein a substance for preventing the formation of the building is fixed. 3. The external wall building material according to claim 1, wherein the substance for preventing the photocatalyst from becoming hydrophilic by photoexcitation is cobalt or a cobalt compound.