Stainproofing film structure

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a membrane structural material used as a roofing material or the like for an indoor stadium such as Tokyo Dome. In particular, the present invention relates to a membrane structural material that is hard to get dirty and has excellent light transmission.

【0002】

[Conventional technology]

In addition to strength and weather resistance, the membrane structural material is required to have light transmission and stain resistance. This is to save lighting by transmitted sunlight and to maintain the aesthetic appearance of the building. Most of the causes of the decrease in light transmission are dirt, so after all, making the surface of the membrane structural material less likely to be dirty is an important factor for maintaining light transmission. The surface of the membrane structural material, especially the outdoor side, is easily contaminated by combustion products such as exhaust gas and soot and dust floating in the atmosphere. Furthermore, cleaning the membrane structural material involves work at a high place, which is costly and dangerous.

【0003】

[Problems to be Solved by the Invention]

Therefore, an object of the present invention is to provide a film structural material that is hard to be soiled.

【0004】

[Means for solving problems]

The present invention provides an antifouling film structural material characterized in that a surface layer containing photocatalytic particles, silicone, and a water-repellent fluororesin is formed on the surface of a base material in order to solve the above problems. .. With such a configuration, when the photocatalyst is photoexcited, the organic group bonded to the silicon atom in the silicone molecule is at least partially replaced with a hydroxyl group by the photocatalytic action to exhibit hydrophilicity, and the silicone becomes hydrophilic. Both the hydrophilic portion exposed to the outside air and the water-repellent portion exposed to the outside air of the water-repellent fluororesin are microscopically dispersed on the surface. Further, due to the presence of the photocatalyst, the silicone in which the organic group bonded to the silicon atom in the silicone molecule is at least partially replaced with a hydroxyl group in response to the photoexcitation of the photocatalyst maintains hydrophilicity permanently. A structure in which both the property-exposing portion and the water-repellent portion are microscopically dispersed on the surface is maintained. In such a structure, since the hydrophilic surface and the water-repellent surface are adjacent to each other, the hydrophilic deposits that easily adapt to the hydrophilic surface do not adapt to the adjacent water-repellent portion. On the contrary, hydrophobic deposits that easily adapt to the water-repellent surface do not adapt to the adjacent hydrophilic part. Therefore, neither the hydrophilic deposit nor the hydrophobic deposit is fixed to the surface of the member, and the surface is maintained in a clean state.

【0005】

Further, the present invention provides an antifouling film structural material characterized in that a surface layer containing photocatalytic particles, amorphous silica and a water-repellent fluororesin is formed on the surface of a base material. With such a configuration, both the hydrophilic portion of the surface layer where the amorphous silica is exposed to the outside air and the water-repellent portion where the water-repellent fluororesin is exposed to the outside air are microscopic on the surface. The structure is dispersed in. Furthermore, due to the presence of the photocatalyst, the atypical silica permanently maintains hydrophilicity in response to the photoexcitation of the photocatalyst, so that both the hydrophilic part and the water-repellent part are microscopically on the surface. The dispersed structure is maintained. In such a structure, since the hydrophilic surface and the water-repellent surface are adjacent to each other, the hydrophilic deposits that easily adapt to the hydrophilic surface do not adapt to the adjacent water-repellent portion. On the contrary, hydrophobic deposits that easily adapt to the water-repellent surface do not adapt to the adjacent hydrophilic part. Therefore, neither the hydrophilic deposit nor the hydrophobic deposit is fixed to the surface of the member, and the surface is maintained in a clean state.

【0006】

BEST MODE FOR CARRYING OUT THE INVENTION

Next, a specific surface structure of the present invention will be described. In one aspect of the present invention, as shown in FIG. 1, a surface layer containing photocatalytic particles, silicone, and a water-repellent fluororesin is formed on the surface of the film structural material base material. When FIG. 1 is irradiated with light capable of photoexciting a photocatalyst, at least a part of the silicone exposed to the outside air becomes a hydroxyl group of an organic group bonded to a silicon atom in a silicone molecule by photocatalytic action. It was replaced and became hydrophilic, and both the hydrophilic part where the silicone was exposed to the outside air and the water-repellent part where the water-repellent fluororesin was exposed to the outside air were microscopically dispersed on the surface. It becomes a structure. Further, due to the presence of the photocatalyst, the silicone in which the organic group bonded to the silicon atom in the silicone molecule is at least partially replaced with a hydroxyl group in response to the photoexcitation of the photocatalyst maintains hydrophilicity permanently. A structure in which both the property-exposing portion and the water-repellent portion are microscopically dispersed on the surface is maintained. With such a structure, neither hydrophilic deposits nor hydrophobic deposits are fixed to the surface of the member, and the surface is maintained in a clean state.

【0007】

In another aspect of the present invention, as shown in FIG. 2, a surface layer containing photocatalytic particles, amorphous silica, and a water-repellent fluororesin is formed on the surface of the film structural material base material. With such a configuration, both the hydrophilic portion of the surface layer where the amorphous silica is exposed to the outside air and the water-repellent portion where the water-repellent fluororesin is exposed to the outside air are microscopic on the surface. The structure is dispersed in. Furthermore, due to the presence of the photocatalyst, the atypical silica permanently maintains hydrophilicity in response to the photoexcitation of the photocatalyst, so that both the hydrophilic part and the water-repellent part are microscopically on the surface. The dispersed structure is maintained. With such a structure, neither hydrophilic deposits nor hydrophobic deposits are fixed to the surface of the member, and the surface is maintained in a clean state.

【0008】

As the film structural material base material, a cloth-like base material made of glass fiber, polyester fiber, acrylic fiber, nylon fiber or the like can be preferably used. In particular, a cloth-like base material made of glass fiber is preferable from the viewpoint of weather resistance and heat resistance. An intermediate layer may be provided between the base material and the surface layer for the purpose of improving the adhesion between the base material and the surface layer.

【0009】

A photocatalyst is an excitation (photoexcitation) of electrons in the valence band when irradiated with light (excitation light) having an energy larger than the energy gap between the conduction band and the valence band of the crystal (that is, a short wavelength). ) Is generated and can generate conduction electrons and holes. Photocatalytic oxides include, for example, anatase-type titanium oxide, rutile-type titanium oxide, zinc oxide, tin oxide, ferric oxide, and trioxide. Oxides such as dibismuth, tungsten trioxide, and strontium titanate can be preferably used. Since the light source used for photoexcitation of the photocatalyst is exposed to the irradiation of the sun during the day, sunlight can be used. In addition, road lighting and the like can be used as a light source at night. The illuminance of the excitation light is 0.001 mW / cm in order for the silicone and atypical silica exposed on the surface of the substrate to be highly hydrophilic by the photoexcitation of the photocatalyst.²More than that is fine, but 0.01mW / cm²Above is preferable, 0.1mW / cm²The above is more preferable.

【0010】

For silicone, the average composition formula R_pSiO_{(4-p) / 2}(In the formula, R is a functional group consisting of one or more monovalent organic groups, or a functional group consisting of two or more selected from a monovalent organic group and a hydrogen group, and X is an alkoxy. A resin represented by a group or a halogen atom, where p is a number satisfying 0 <p <2) can be used.

【0011】

As the water-repellent fluororesin, polytetrafluoroethylene, polychlorotrifluoroethylene, polyhexafluoropropylene, tetrafluoroethylene-hexafluoropropylene copolymer and the like can be preferably used.

【0012】

The film thickness of the surface layer is preferably 0.4 μm or less. By doing so, it is possible to prevent white turbidity due to diffused reflection of light, and the surface layer becomes substantially transparent. Further, it is more preferable that the film thickness of the surface layer is 0.2 μm or less. By doing so, it is possible to prevent color development of the surface layer due to light interference. Further, the thinner the surface layer, the higher the transparency. Further, if the film thickness is reduced, the wear resistance of the surface layer is improved.

【0013】

Metals 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 mold adhering to the surface even in a dark place.

【0014】

Platinum group metals such as Pt, Pd, Ru, Rh, Ir and Os can be added to the surface layer. The surface layer to which the metal is added can enhance the redox activity of the photocatalyst, and can improve the decomposability of organic stains and the decomposability of harmful gases and malodors.

【0015】

Next, a method for producing an antifouling member in which a surface layer containing photocatalytic oxide particles, silicone, and a water-repellent fluororesin is formed on the surface of the base material will be described. The manufacturing method in this case is basically by applying the coating composition to the surface of the base material and curing it.

【0016】

Here, the coating composition requires a precursor of silicone in addition to photocatalyst particles and a water-repellent fluororesin, and other solvents such as water, ethanol and propanol, hydrochloric acid, nitrate, sulfuric acid, acetic acid, maleic acid and the like. A catalyst that promotes hydrolysis of the silicone precursor, or a catalyst that cures a silicone precursor such as basic compounds such as tributylamine and hexylamine, and acidic compounds such as aluminum triisopropoxide and tetraisopropyl titanate. Alternatively, a surfactant or the like that improves the dispersibility of the coating liquid such as a silane coupling agent may be added.

【0017】

Here, as a precursor of silicone, an average composition formula R_pSiX_qO_{(4-pq) / 2}(In the formula, R is a functional group consisting of one or more monovalent organic groups, or a functional group consisting of two or more selected from a monovalent organic group and a hydrogen group, and X is an alkoxy. A coating element consisting of a siloxane which is a group or a halogen atom and p and q are numbers satisfying 0 <p <2 and 0 <q <4), or a general formula. R_pSiX_4-p(In the formula, R is a functional group consisting of one or more monovalent organic groups, or a functional group consisting of two or more selected from a monovalent organic group and a hydrogen group, and X is an alkoxy. A coating-forming element composed of a hydrolyzable silane derivative represented by a group or a halogen atom and p being 1 or 2) can be preferably used.

【0018】

Here, examples of the coating film-forming element composed of the hydrolyzable silane derivative include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and ethyltripropoxy. Silane, ethyltributoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, phenyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, Diethyldiethoxysilane, diethyldipropoxysilane, diethyldibutoxysilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, phenylmethyldipropoxysilane, phenylmethyldibutoxysilane, n-propyltrimethoxysilane, n-propyltriethoxy. Silane, n-propyltripropoxysilane, n-propyltributoxysilane, γ-glycoxydoxypropyltrimethoxysilane, γ-acryloxypropyltrimethoxysilane, and the like can be preferably used.

【0019】

Examples of the coating film-forming element composed of the above-mentioned siloxane include partial hydrolysis and dehydration-reduction polymerization of the above-mentioned hydrolyzable silane derivative, or partial hydrolysis of the above-mentioned hydrolyzable silane derivative, and tetramethoxysilane and tetraethoxysilane. It can be produced by dehydration-condensation polymerization with a partial hydrolyzate such as tetrapropoxysilane, tetrabutoxysilane, or diethoxydimethoxysilane.

【0020】

As a coating method of the coating composition, a spray coating method, a dip coating method, a flow coating method, a spin coating method, a roll coating method, a brush coating, a sponge coating and the like can be preferably used. As a curing method, it can be polymerized by heat treatment, leaving at room temperature, irradiating with ultraviolet rays, or the like.

【0021】

Next, a method for producing an antifouling member in which a surface layer containing photocatalytic particles, amorphous silica, and a water-repellent fluororesin is formed on the surface of the base material will be described. The manufacturing method in this case is basically by applying the coating composition to the surface of the base material and curing it.

【0022】

Here, the coating composition requires silica particles or a precursor of silica as an essential constituent in addition to the photocatalyst particles and the water-repellent fluororesin, and other solvents such as water, ethanol and propanol, hydrochloric acid, nitric acid, sulfuric acid, acetic acid, etc. Catalysts that promote the hydrolysis of silica precursors such as maleic acid, basic compounds such as tributylamine and hexylamine, and silica precursors such as acidic compounds such as aluminum triisopropoxide and tetraisopropyl titanate. A curing catalyst or a surfactant that improves the dispersibility of the coating liquid such as a silane coupling agent may be added.

【0023】

Here, as a precursor of silicone, an average composition formula SiX_qO_{(4-q) / 2}(In the formula, X is an alkoxy group or a halogen atom, and q is a number satisfying 0 <q <4). SiX₄(In the formula, R is a functional group consisting of one or more monovalent organic groups, or a functional group consisting of two or more selected from a monovalent organic group and a hydrogen group, and X is an alkoxy. A coating film-forming element composed of a tetrafunctional hydrolyzable silane derivative represented by a group or a halogen atom) can be preferably used.

【0024】

Here, as a coating film-forming element composed of the above-mentioned tetrafunctional hydrolyzable silane derivative, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, diethoxydimethoxysilane and the like can be preferably used.

【0025】

The coating film-forming element composed of the silicate can be produced by partial hydrolysis and dehydration polycondensation of the tetrafunctional hydrolyzable silane derivative.

【0026】

As a coating method of the coating composition, a spray coating method, a dip coating method, a flow coating method, a spin coating method, a roll coating method, a brush coating, a sponge coating and the like can be preferably used. As a curing method, it can be polymerized by heat treatment, leaving at room temperature, irradiating with ultraviolet rays, or the like.

【0027】

[Example]

Reference example. Anatase type titanium oxide sol (Nissan Chemical Industries, Ltd., TA-15, nitric acid lytic type, pH = 1), silica sol (Nippon Synthetic Rubber, Glasca A solution, pH = 4), and methyltrimethoxysilane (Nippon Synthetic Rubber) , Grasca B solution) and ethanol, and the coating solution obtained by stirring for 2 to 3 minutes is applied on a 10 cm square soda lime glass substrate by the spray coating method, and heat-treated at 200 ° C for 15 minutes. A # 1 sample having a surface layer consisting of 11 parts by weight of anatase-type titanium oxide particles, 6 parts by weight of silica, and 5 parts by weight of silicone was obtained. The contact angle of the # 1 sample with water was 85 °. Here, the contact angle with water was evaluated using a contact angle measuring device (Kyowa Interface Science, CA-X150) based on the contact angle with water 30 seconds after dropping water droplets from a microsyringe. Next, on the surface of the # 1 sample, use an ultraviolet light source (Sankyo Electric, Black Light Blue (BLB) fluorescent lamp) at 0.3 mW / cm.²A # 2 sample was obtained by irradiating with the ultraviolet illuminance of the above for one day. As a result, the contact angle of the # 2 sample with water was hydrophilized to 0 °. Next, the # 1 sample and the # 1 sample were charged with a mercury lamp at 22.8 mW / cm.²The surface of each of the # 3 samples obtained by irradiating with the ultraviolet illuminance of No. 3 for 2 hours was subjected to Raman spectroscopic analysis. As a result, the peak of the methyl group observed on the surface of the # 1 sample was not observed in the # 3 sample, but instead the broad peak of the hydroxyl group was observed. From the above, the organic group bonded to the silicon atom in the silicone molecule on the surface of the coating in response to the photoexcitation of the anatase-type titanium oxide, which is a photocatalyst, is replaced with a hydroxyl group by the photocatalytic action and becomes hydrophilic. I understand.

【0028】

Example. Anatase-type titanium oxide sol (Nissan Kagaku, TA-15), silica sol (Nippon Synthetic Rubber, Glasca A solution), methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B solution) and polytetrafluoroethylene (PTFE). The coating solution obtained by mixing particles (Daikin Industries, Lubron L-5) and ethanol and stirring for 2 to 3 hours is applied on a 10 cm square glass cloth substrate by the spray coating method, and at 200 ° C. Heat treatment was performed for 15 minutes to obtain a # 4 sample having a surface layer consisting of 33 parts by weight of anatase-type titanium oxide particles, 66 parts by weight of polytetrafluoroethylene particles, 6 parts by weight of silica, and 5 parts by weight of silicone. The contact angle of the # 4 sample with water was 110 °. Next, on the surface of the # 4 sample, use an ultraviolet light source (Sankyo Electric, Black Light Blue (BLB) fluorescent lamp) at 0.3 mW / cm.²A # 5 sample was obtained by irradiating with the ultraviolet illuminance of No. 1 for one day. As a result, the contact angle of the # 5 sample with water was 97.4 °, which was not so different. From the above reference example, in the portion where the silicone is exposed to the outside air, the organic group bonded to the silicon atom in the silicone molecule should be replaced with a hydroxyl group by the photocatalytic action and hydrophilized. It is considered that the contact angle with and was slightly reduced. That is, on the surface of the # 5 sample, both the part where the hydrophilic silicone is exposed to the outside air and the part where the water-repellent fluororesin is exposed to the outside air and the part where the water-repellent fluororesin is exposed to the outside air are both replaced with hydroxyl groups by photocatalysis. It is presumed that the structure is microscopically dispersed on the surface.

【0029】

Next, the # 5 sample and polytetrafluoroethylene (PTFE) and glass cloth were installed outdoors for comparison, and the cleanliness and maintenance of the surface against deposits and contaminants were examined. The cleanliness and maintenance of the surface against sediments and contaminants was performed by placing a sample under the covered part of the roof of the building as shown in Fig. 3 and exposing it for 4 months. As a result, stains were conspicuous with polytetrafluoroethylene, and some stains were observed with the glass cloth, whereas no stains were observed with the # 5 sample.

【0030】

[Effect of the invention]

In the present invention, in the film structural material, a surface layer containing photocatalytic particles, silicone and a water-repellent fluororesin is formed on the surface of the base material, or photocatalytic particles and amorphous silica are formed on the surface of the base material. By forming a surface layer containing the water-repellent fluororesin and the water-repellent fluororesin, neither hydrophilic deposits nor hydrophobic deposits are fixed to the surface of the member, and the surface is maintained in a clean state. Will be done.

[Simple explanation of drawings]

[Figure 1]

The figure which shows the surface structure of the membrane structural material which concerns on this invention.

[Figure 2]

The figure which shows the other surface structure of the membrane structural material which concerns on this invention.