JPH10100901A - Antifouling rolling stock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a surface in a clean state without hydrophilic and hydrophobic attachment sticking to the surface of members by forming a surface layer containing photocataiyst grain, silicone and water-repellent fluororesin, on the outside surface of a rolling stock. SOLUTION: A surface layer containing photocatalyst grain, silicone and water-repellent fluororesin is formed on the outside surface of a rolling stock. When photocatalyst photo-excitative light is irradiated, in part of silicone exposed to outside air, an organic group bound to a silicon atom in a silicone molecule is partially suabstituted with a hydroxyl group by photocatalyst action so as to display a hydrophilic property. The surface layer therefore has such structure that a, part displaying a hydrophilic property with silicone exposed to outside air and a part displaying water repellency with water-repellent fluororesin exposed to outside air are both microscopically dispersed on the surface. Further with the presence of a photocatalyst, amorphous silica permanently maintains the hydrophilic property in response to photo-excitation of the photocatalyst so as to maintain this structure with both hydrophilic and water-repellent parts micro-scopically dispersed on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifouling railway vehicle which is hardly contaminated with dust and the like.

[0002]

2. Description of the Related Art An unpainted steel plate, a stainless steel plate, or a material obtained by coating them with acrylic, urethane, or the like is often used on the outside of a railway vehicle.

[0003]

The outside of a railway vehicle is contaminated with soot in exhaust gas, dust soaring from a road surface or the ground, abrasion powder of a rail and a brake brake, and abrasion powder of a slide plate and an overhead wire. . For this reason, cleaning is performed once every 1 to 10 days in a painted vehicle in which dirt is conspicuous in particular. However, the above cleaning work requires a great deal of labor. Frequent cleaning also requires plenty of water, detergent, electricity,
Labor required and costly. The present invention has been made in view of the above circumstances, and has as its object to provide a railway vehicle that is less likely to be soiled outside the vehicle.

[0004]

In order to solve the above-mentioned problems, the present invention is characterized in that a surface layer containing photocatalyst particles, silicone and a water-repellent fluororesin is formed on the outer surface of a railway vehicle. To provide an antifouling railway vehicle.
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 by a hydroxyl group by the photocatalytic action, so that the silicone becomes hydrophilic. Both the hydrophilic part exposed to the outside air and the water-repellent part exposed to the outside air are microscopically dispersed on the surface. Furthermore, the presence of the photocatalyst allows the silicone in which the organic group bonded to the silicon atom in the silicone molecule is at least partially substituted with a hydroxyl group in response to the photoexcitation of the photocatalyst to remain permanently hydrophilic. The structure in which both the portion exhibiting the property and the portion exhibiting the water repellency 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 adherent that easily adapts to the hydrophilic surface does not adapt to the adjacent water-repellent portion. Conversely, hydrophobic deposits that are easily adapted to the water-repellent surface do not adapt to adjacent hydrophilic portions. Therefore, neither the hydrophilic deposit nor the hydrophobic deposit is fixed to the member surface, and the surface is maintained in a clean state.

Further, the present invention provides an antifouling railway vehicle characterized in that a surface layer containing photocatalyst particles, amorphous silica and a water-repellent fluororesin is formed on the outer surface of the railway vehicle. I do. With this configuration, both the amorphous silica in the surface layer and the water-repellent portion where the water-repellent fluororesin is exposed to the outside are exposed on the surface. It becomes the structure distributed in. Further, the presence of the photocatalyst allows the amorphous silica to maintain its hydrophilicity permanently in response to the photoexcitation of the photocatalyst, so that both the hydrophilic portion and the water-repellent portion are microscopically visible on the surface. The distributed structure is maintained. In such a structure, since the hydrophilic surface and the water-repellent surface are adjacent to each other, the hydrophilic adherent that easily adapts to the hydrophilic surface does not adapt to the adjacent water-repellent portion. Conversely, hydrophobic deposits that are easily adapted to the water-repellent surface do not adapt to adjacent hydrophilic portions. Therefore, neither the hydrophilic deposit nor the hydrophobic deposit is fixed to the member surface, and the surface is maintained in a clean state.

[0006]

Next, a specific configuration of the present invention will be described. First, the outer surface structure of the railroad vehicle on the railroad according to the present invention will be described. In one embodiment of the present invention, as shown in FIG. 1, a surface layer containing photocatalyst particles, silicone, and a water-repellent fluororesin is formed on the outer surface of a railway vehicle. When light capable of photo-exciting the photocatalyst is irradiated to FIG. 1, at least a part of the silicone exposed to the outside air becomes at least partially converted into a hydroxyl group by an organic group bonded to a silicon atom in the silicone molecule by a photocatalytic action. As a result of the substitution, it became hydrophilic, and both the silicone-exposed hydrophilic part exposed to the outside air and the water-repellent fluororesin exposed to the air and the water-repellent part were microscopically dispersed on the surface. Structure. Further, the presence of the photocatalyst allows the amorphous silica to maintain its hydrophilicity permanently in response to the photoexcitation of the photocatalyst, so that both the hydrophilic portion and the water-repellent portion are microscopically visible on the surface. The distributed structure is maintained. With such a structure, neither the hydrophilic deposit nor the hydrophobic deposit is fixed to the member surface, and the surface is maintained in a clean state.

In another embodiment of the present invention, as shown in FIG. 2, a surface layer containing photocatalyst particles, amorphous silica, and a water-repellent fluororesin is formed on the outer surface of a railway vehicle. With this configuration, both the amorphous silica in the surface layer and the water-repellent portion where the water-repellent fluororesin is exposed to the outside are exposed on the surface. It becomes the structure distributed in. further,
Due to the presence of the photocatalyst, the amorphous silica permanently maintains hydrophilicity in response to photoexcitation of the photocatalyst, so that both the hydrophilic portion and the water-repellent portion are microscopically dispersed on the surface. Structure is maintained. With such a structure, neither the hydrophilic deposit nor the hydrophobic deposit is fixed to the member surface, and the surface is maintained in a clean state.

An unpainted steel plate, a stainless steel plate, or a material obtained by coating them with acrylic, urethane, or the like can be used on the outside of the railway vehicle.

A photocatalyst is a device that emits light (excitation light) having an energy (ie, shorter wavelength) larger than the energy gap between the conduction band and the valence band of a crystal when the electrons in the valence band are irradiated. A substance capable of generating conduction electrons and holes by excitation (photoexcitation). Photocatalytic oxides include, for example, anatase-type titanium oxide, rutile-type titanium oxide, zinc oxide, tin oxide, and ferric oxide. And oxides such as bismuth trioxide, tungsten trioxide and strontium titanate. The light source used for photoexcitation of the photocatalyst is exposed to sunlight during the day, so that sunlight can be used. In the nighttime, garage lighting or the like can be used as a light source. In order for the substrate surface to be highly hydrophilic by photoexcitation of the photocatalyst, the illuminance of the excitation light is 0.001 mW / cm ^2.
May be at least, but preferably that it 0.01 mW / cm ² or more, and more preferably it 0.1 mW / cm ² or more.

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 formula: X is an alkoxy group or a halogen atom, and p is a number satisfying 0 <p <2). Available.

As the water-repellent fluororesin, polytetrafluoroethylene, polychlorotrifluoroethylene, polyhexafluoropropylene, tetrafluoroethylene-hexafluoropropylene copolymer 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. Further, it is more preferable that the thickness of the surface layer be 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 has been added can kill bacteria and shadows adhering 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 method for producing an antifouling member in which a surface layer containing photocatalytic oxide particles, silicone and a water-repellent fluororesin is formed on a substrate surface will be described. The production method in this case is basically based on applying a coating composition to the surface of a substrate and curing the composition.

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

[0017] Here, as the precursor of a silicone, in the average composition formula _{R p SiX q O (4-} p-q) / 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 <
q <film forming element comprising a siloxane represented by 4 is a number satisfying), or the general formula R p _SiX 4-p _(wherein, R is from one or more of the monovalent organic group Or a functional group consisting of two or more selected from a monovalent organic group and a hydrogen group, wherein X is an alkoxy group,
Alternatively, a film-forming element composed of a hydrolyzable silane derivative represented by a halogen atom and p is 1 or 2) 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, Phenylmethyldipropoxysilane, 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 above-mentioned siloxane includes partial hydrolysis and dehydration-condensation polymerization of the above-mentioned hydrolyzable silane derivative, or partially hydrolyzate of the above-mentioned hydrolyzable silane derivative, tetramethoxysilane and tetramethoxysilane. It can be produced by dehydration polycondensation with a partial hydrolyzate such as ethoxysilane, tetrapropoxysilane, tetrabutoxysilane, diethoxydimethoxysilane and the like.

As the method for applying the coating composition, methods such as spray coating, dip coating, flow coating, spin coating, roll coating, brush coating, and sponge 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 method for producing an antifouling member in which a surface layer containing photocatalyst particles, amorphous silica and a water-repellent fluororesin is formed on the surface of a substrate will be described. The production method in this case is basically based on applying a coating composition to the surface of a substrate and curing the composition.

The coating composition contains silica particles or a silica precursor in addition to photocatalyst particles and a water-repellent fluororesin as essential components. In addition, a solvent such as water, ethanol, propanol, hydrochloric acid, nitric acid, and sulfuric acid are used. , Acetic acid, catalysts that promote the hydrolysis of silica precursors such as maleic acid, and silica such as basic compounds such as tributylamine and hexylamine, and acidic compounds such as aluminum triisopropoxide and tetraisopropyl titanate. A catalyst for curing the precursor or a surfactant for improving the dispersibility of the coating liquid such as a silane coupling agent may be added.

Here, the precursor of the silicone includes an average composition formula SiX _q O _{(4-p) / 2} (where X is an alkoxy group or a halogen atom, and q satisfies 0 <q <4). A film-forming element composed of a silicate represented by the following formula: or a general formula SiX ₄ (wherein R is a functional group composed of one or more monovalent organic groups, or a monovalent organic group) Is a functional group consisting of two or more selected from an organic group and a hydrogen group, wherein X is an alkoxy group,
Alternatively, a film-forming element made of a tetrafunctional hydrolyzable silane derivative represented by a halogen atom) can be suitably used.

Here, as the coating film forming element comprising the above-mentioned tetrafunctional hydrolyzable silane derivative, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane,
Tetrabutoxysilane, diethoxydimethoxysilane and the like can be suitably used.

The coating film-forming element comprising the silicate can be produced by partial hydrolysis, dehydration-condensation polymerization or the like of the above-mentioned tetrafunctional hydrolyzable silane derivative.

As a method for applying the above coating composition, methods such as spray coating, dip coating, flow coating, spin coating, roll coating, brush coating, and sponge 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.

[0027]

【Example】

Reference example. Anatase type titanium oxide sol (Nissan Chemical, TA
-15, nitric acid peptizing type, pH = 1), silica sol (Nippon Synthetic Rubber, Glasca A solution, pH = 4), methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B solution) and ethanol were mixed. The coating liquid obtained by stirring for about 3 minutes is applied to a 10 cm square soda lime glass substrate by a spray coating method, and heat-treated at 200 ° C. for 15 minutes to obtain 11 parts by weight of anatase type titanium oxide particles and silica 6 A # 1 sample having a surface layer composed of 5 parts by weight of silicone 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) by the contact angle with water 30 seconds after a water droplet was dropped from the micro syringe.
Next, 0.3 mW was applied to the surface of the # 1 sample using an ultraviolet light source (Sankyo Electric, black light blue (BLB) fluorescent lamp).
The sample was irradiated for 1 day with an ultraviolet illuminance of / cm ² to obtain a # 2 sample.
As a result, the contact angle with water of the # 2 sample was hydrophilized to 0 °. Next, a mercury lamp was used for the sample # 1 and the sample # 2 for 22.8.
The sample surface of each of the # 3 samples obtained by irradiating with an ultraviolet illuminance of mW / cm ² for 2 hours was subjected to Raman spectroscopic analysis. as a result,#
The peak of the methyl group observed on the surface of one sample was not observed in the # 3 sample, but a broad peak of the hydroxyl group was observed instead. 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 photocatalytic anatase-type titanium oxide is replaced with a hydroxyl group by photocatalysis, and is hydrophilized. I understand.

Embodiment 1 FIG. Anatase type titanium oxide sol (Nissan Chemical Co., TA-15), silica sol (Nippon Synthetic Rubber, Glasca A solution), methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B solution) and polytetrafluoroethylene (PTFE) particles (Daikin) Industrial, Lubron L-
5) was mixed with ethanol and stirred for 2 to 3 hours.
A surface layer composed 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, applied on a square stainless steel substrate and heat-treated at 200 ° C. for 15 minutes. Formed #
Four samples were obtained. The contact angle of the # 4 sample with water was 110 °. Next, an ultraviolet light source (Sankyo Electric,
Black light blue (BLB) fluorescent light).
Irradiation was performed at an ultraviolet illuminance of 3 mW / cm ² for 1 day to obtain a # 5 sample. As a result, the contact angle of the # 5 sample with water was 97.4 °, and did not change much. According to the above reference example, the portion where the silicone is exposed to the outside air is supposed to be replaced by a hydroxyl group by a photocatalytic action and the organic group bonded to the silicon atom in the silicone molecule to be hydrophilized. It is considered that the contact angle with the film slightly decreased. In other words, the surface of the # 5 sample has both a hydrophilic portion where the hydroxyl group is substituted by the photocatalytic action and the hydrophilicized silicone is exposed to the outside air and a water-repellent portion where the water-repellent fluororesin is exposed to the outside air. It is assumed that the structure is microscopically dispersed on the surface.

Next, the # 5 sample and a stainless steel plate were placed outdoors for comparison, and the cleanliness of the surface against deposits and contaminants was examined. The cleanliness of the surface against sediment and contaminants was determined by placing the sample as shown in FIG. 4 below the rooftop of the building and exposing it for 4 months. As a result, while some stains were observed on the stainless steel plate, no stain was observed on the # 5 sample.

Example 2. A primer paint (Toshiba silicone, a paint obtained by diluting PH93 6 times with toluene solvent) was applied to the surface of a 10 cm square PMMA plate by a spray coating method, and then dried at room temperature. It was covered with a resin layer. Next, a silicone-based hard coating agent (Toshiba Silicone, Tosgard) was applied by a flow coating method, and heat-treated at 90 ° C. for 3 hours to obtain a hard coat layer. Further, anatase type titanium oxide sol (Nissan Chemical Co., TA-15), silica sol (Nippon Synthetic Rubber, Glasca A solution), methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B solution) and polytetrafluoroethylene (PTFE) Particles (Daikin Industries, Lubron L-5) and ethanol are mixed, and a coating solution obtained by stirring for 2 to 3 hours is applied by a spray coating method, and is heat-treated at 90 ° C. for 3 hours, and is then anatase A # 6 sample having a surface layer composed of 33 parts by weight of titanium oxide particles, 66 parts by weight of polytetrafluoroethylene particles, 6 parts by weight of silica and 5 parts by weight of silicone was obtained. The contact angle with water of the # 6 sample was 107 °. Then on the # 6 sample surface,
UV light source (Sankyo Electric, Black Light Blue (BL
B) A fluorescent lamp) was used to irradiate at 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 96.4 °, and did not change much. According to the above reference example, the portion where the silicone is exposed to the outside air is supposed to be replaced by a hydroxyl group by a photocatalytic action and the organic group bonded to the silicon atom in the silicone molecule to be hydrophilized. It is considered that the contact angle with the film slightly decreased. In other words, the surface of the # 7 sample has both a hydrophilic portion where the hydroxyl group is substituted by the photocatalytic action and the hydrophilicized silicone is exposed to the outside air and a water-repellent portion where the water-repellent fluororesin is exposed to the outside air. It is assumed that the structure is microscopically dispersed on the surface.

Next, the # 7 sample and a PMMA plate were placed outdoors for comparison, and the cleanliness of the surface against deposits and contaminants was examined. The cleanliness of the surface against sediment and contaminants was determined by placing the sample as shown in FIG. 4 below the rooftop of the building and exposing it for 4 months. As a result, a considerable stain was observed on the PMMA plate, whereas no stain was observed on the # 7 sample.

[0032]

According to the present invention, in a railway vehicle, a surface layer containing photocatalyst particles, silicone and a water-repellent fluororesin is formed on the outer surface of the railway vehicle, or By forming a surface layer containing photocatalyst particles, amorphous silica and a water-repellent fluororesin on the surface of the base material, both the hydrophilic deposit and the hydrophobic deposit are fixed to the member surface. Never
The surface will be kept clean.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outer surface structure of a railway vehicle according to the present invention.

FIG. 2 is a diagram showing another surface structure outside the railway vehicle according to the present invention.

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

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // (C09D 127/12 183: 04)

Claims (2)

[Claims] 1. An antifouling railway vehicle, wherein a surface layer containing photocatalytic oxide particles, silicone and a water-repellent fluororesin is formed on an outer surface of the railway vehicle. 2. An antifouling railway vehicle, wherein a surface layer containing photocatalytic oxide particles, amorphous silica, and a water-repellent fluororesin is formed on an outer surface of the railway vehicle.