JPH10287239A - Stone flying accident-preventing rolling stock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the snow adhered to a body hard to fall by providing a surface layer containing a photocatalytic particle on the outer surface of a rolling stock, and making the surface of the layer hydrophilic according to the light excitation of the photocatalyst. SOLUTION: In the outer surface of a rolling stock, a layer containing a photocatalyst is formed on the surface of a base. When the surface layer consists of only the photocatalyst, the photocatalyst preferably consists of an oxide. Since the oxide is hydrophilic in the state where the environmental contaminant is not adsorbed, the contaminant is eliminated by light exciting effect to form an adsorptive water layer, whereby an uniform water membrane apt to show hydrophilic property can be formed. The high hydrophilic property means the property extremely familiar with water when it is dropped on the surface, and more specifically, the state where water wet angle is about 10 deg. or less, more preferably, about 5 deg. or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a railway vehicle capable of preventing a stepping stone accident caused by falling snow on a vehicle body.

[0002]

BACKGROUND OF THE INVENTION Snow and ice damage is a serious problem in transportation. In particular, a stepping stone accident caused by falling snow on a car body is, for example, a crushed stone track (tracked track) on the Tokaido Shinkansen. Has caused delays in trains, causing a great deal of inconvenience to passengers (Ma
terials Life Vol.3, No.1 (1991), p.48).

[0003]

Therefore, in the present invention,
It is an object of the present invention to provide a railway vehicle having a surface on which snowfall of a vehicle body does not easily fall and capable of maintaining its properties for a long period of time.

[0004]

SUMMARY OF THE INVENTION The present invention is based on the discovery that, in a member having a surface layer containing a photocatalyst formed thereon, when the photocatalyst is photoexcited, the surface of the member is highly hydrophilized. This phenomenon is considered to proceed by the following mechanism. That is, when light having energy equal to or more than the energy gap between the upper end of the valence band and the lower end of the conduction band of the photocatalyst is irradiated on the photocatalyst, the electrons in the valence band of the photocatalyst are excited, and the conduction electrons and holes are generated. Produced, either or both of these actions, presumably polarize the surface, collecting polar components such as water and hydroxyl groups. Then, due to the coordinated action of one or both of the conduction electrons and holes and the polar component, the chemically adsorbed water is adsorbed on the surface, and a physically adsorbed water layer is formed thereon. Further, once the surface of the member is highly hydrophilized, the hydrophilicity of the surface is maintained for a certain period even if the member is kept in a dark place.

According to the present invention, a stepping stone accident is provided in which a surface layer containing photocatalyst particles is provided on the outer surface of a vehicle, and the surface of the layer becomes hydrophilic in response to photoexcitation of the photocatalyst. Provide an anti-railroad vehicle. By the way, it is considered that snow accretion on the outer surface of the vehicle is caused by the fact that the attached snow solidifies while melting partly and accumulates while the process is repeated. It is conceivable that the nuclei are deposited while growing non-uniformly in some places, so that irregularities are generated on the surface, and extra force due to centrifugal force, vibration, etc. is applied to the convex parts when the train is running. By providing a surface layer containing a photocatalyst,
Since the surface of the surface layer becomes hydrophilic in response to the photoexcitation of the photocatalyst, the attached snow is uniform when a part of the snow melts, and therefore ice nuclei are hardly formed, so that at least the surface is unevenly snowed. Never do. Therefore, the scattering of the stepped snow is effectively prevented. In a preferred embodiment of the present invention, it is preferable that the outer surface of the railway vehicle has no irregularities. It is preferable that the average roughness Ra of the surface is 10 μm or less,
More preferably, Ra is 1 μm or less.

In a preferred embodiment of the present invention, the surface layer further contains silica. By containing silica, the surface is likely to exhibit a high degree of hydrophilicity near a water wetting angle of 0 °, and the hydrophilicity retention when held in a dark place is improved. The reason seems to be related to the fact that silica can store water in its structure.

In a preferred embodiment of the present invention, the surface layer further contains a solid acid. When the solid acid is contained, the surface is likely to exhibit a high degree of hydrophilicity near a water wetting angle of 0 °, and the hydrophilicity retention when kept in a dark place is improved. The reason is that when a solid acid is contained in the surface layer, the polarity of the surface is large regardless of the presence or absence of light, so it is easier to selectively adsorb water molecules that are polar molecules than hydrophobic molecules. . Therefore, a stable physical adsorption water layer is easily formed, and even if it is kept in a dark place,
Surface hydrophilicity can be maintained at a high level for a fairly long time.

In a preferred embodiment of the present invention, the surface layer further contains silicon.
When silicon is contained, at least a part of the organic group bonded to the silicon atom in the silicon is replaced by a hydroxyl group by photoexcitation of the photocatalyst, and a physical adsorption water layer is formed thereon. As a result, the surface exhibits a high degree of hydrophilicity close to the water wetting angle of 0 °, and the hydrophilicity retention when held in a dark place is improved.

[0009]

Next, a specific configuration of the present invention will be described. On the outer surface of the railway vehicle in the present invention,
As shown in FIG. 1 or FIG. 2, a layer containing a photocatalyst is formed on the surface of the substrate.

In FIG. 1, when the surface layer comprises only a photocatalyst, the photocatalyst is preferably an oxide.
By doing so, the oxide shows hydrophilicity in the state where the pollutants in the environment are not adsorbed, so that the pollutants are rejected by the photoexcitation action and the adsorbed water layer is formed, so that the oxides easily exhibit hydrophilicity. A uniform water film can be formed. In FIG. 2, M represents a metal element. Therefore, in the case of FIG. 2, the outermost surface is made of a general inorganic oxide. Again,
Since the oxide shows hydrophilicity in a state where the pollutant in the environment is not adsorbed, the pollutant is rejected by a photoexcitation effect of a photocatalyst mixed into the surface layer other than the inorganic oxide,
By forming the adsorbed water layer, a uniform water film can be formed.

A photocatalyst has an energy larger 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).
Ze-type titanium oxide, rutile-type titanium oxide, tin oxide, zinc oxide, bismuth trioxide, tungsten trioxide, ferric oxide, strontium titanate and the like can be suitably used. Here, as a light source used for photoexcitation of the photocatalyst, there can be used sunlight; a light source in an environment such as a streetlight or a nightlight; As a dedicated irradiation light source, a metal halide lamp, a black light lamp, a xenon lamp, a mercury lamp and the like can be suitably used. In order for the substrate surface to be highly hydrophilic by photoexcitation of the photocatalyst, the illuminance of the excitation light must be
0.001 mW / cm ² or more is sufficient,
It is preferably at least W / cm ^2, more preferably at least 0.1 mW / cm ² .

The thickness of the surface layer containing the photocatalyst is 0.4
It is preferable that the thickness be not more than μm. 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 containing the photocatalyst 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. The surface of the surface layer may be further provided with a wear-resistant or corrosion-resistant protective layer capable of being made hydrophilic and other functional films.

A metal such as Ag, Cu, or 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.

The surface layer includes Pt, Pd, Ru, R
A platinum group metal such as h, Ir, Os can be added. The surface layer to which the metal is added can enhance the oxidation-reduction activity of the photocatalyst and improve the deodorizing and purifying action and the like. In addition, when a solid acid is added in addition to the photocatalyst, the acidity of the solid acid is improved by the addition of a platinum group metal, so that the hydrophilicity is also improved, and the formation of a water film on the attached water is further promoted. The hydrophilicity when the excitation light is not irradiated to the photocatalyst for a long period of time is also improved. Mo may be added to the surface layer. Also in this case, when a solid acid is added in addition to the photocatalyst, the acidity of the solid acid is improved, so that the hydrophilicity retention property is also improved, the water film of the attached water is further promoted, and the photocatalyst is excited for a long period of time. Is also improved when not irradiated.

When the substrate is a glass containing alkali network modifying ions such as sodium (soda lime glass, side-by-side glass, etc.), an intermediate layer such as silica is formed between the substrate and the surface layer. You may. Then, the diffusion of the alkali network modifying ions from the base material to the surface layer during the firing is prevented, and the photocatalytic function is more effectively exhibited.

The term "hydrophilic" refers to the property of being easily conformed when water is dropped on the surface, and generally refers to a state where the water wetting angle is less than 90 °. The high hydrophilicity in the present invention refers to a property that is very compatible when water is dropped on the surface, and more specifically, a water wetting angle is 20 ° or less, preferably about 10 ° or less, more preferably 5 ° or less.状態 Refers to the state of being below.

[0017] The solid acid of the present invention refers to acid comprising the components of the solid oxide, specifically, sulfuric acid supported Al ₂
O ₃ , sulfuric acid supported TiO ₂ , sulfuric acid supported ZrO ₂ , sulfuric acid supported S
nO ₂ , sulfuric acid supported Fe ₂ O ₃ , sulfuric acid supported SiO ₂ , sulfuric acid supported HfO ₂ , TiO ₂ / WO ₃ , WO ₃ / SnO ₂ , WO ₃ / Z
_{rO 2, WO 3 / Fe 2} O 3, SiO 2 · Al 2 O 3, TiO 2
/ SiO ₂ , TiO ₂ / Al ₂ O ₃ , TiO ₂ / ZrO _{2 and the} like can be suitably used.

Next, a method for forming the surface layer will be described. First, a production method in the case where the surface layer is made of only a photocatalyst will be described with reference to an example where the photocatalyst is an anatase type titanium oxide. In this case, there are roughly three methods. One method is a sol coating and baking method, the other method is an organic titanate method, and the other method is an electron beam evaporation method. (1) Sol coating and baking method An anatase type titanium oxide sol is sprayed on the surface of a substrate.
Coating method, dip coating method, flow coating
It is applied by a coating method, a spin coating method, a roll coating method, or the like, and baked. (2) Organic titanate method Titanium alkoxides (tetraethoxytitanium, tetramethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium, etc.), titanium acetate, titanium chelate, and other organic titanates are treated with a hydrolysis inhibitor (hydrochloric acid, Ethylamine, etc.), and alcohol (ethanol, propanol)
, Butanol, etc.), and after partially or completely proceeding the hydrolysis, the mixture is spray-coated, dip-coated. , Flow coating method, Spin coating
Coating method, roll coating method, etc.
dry. By drying, hydrolysis of the organic titanate is completed to produce titanium hydroxide, and a layer of amorphous titanium oxide is formed on the surface of the base material by dehydration-condensation polymerization of the titanium hydroxide. Thereafter, the amorphous titanium oxide is calcined at a temperature higher than the crystallization temperature of the anatase to cause a phase transition from the amorphous titanium oxide to the anatase titanium oxide. (3) Electron beam evaporation method An amorphous titanium oxide layer is formed on the surface of a substrate by irradiating a target of titanium oxide with an electron beam. After that, firing at a temperature higher than the crystallization temperature of the anatase,
Amorphous titanium oxide undergoes a phase transition to an anatase type titanium oxide.

Next, the case where the surface layer is composed of a photocatalyst and silica will be described with reference to the case where the photocatalyst is an anatase type titanium oxide. In this case, for example, there are the following three methods. One method is a sol coating and baking method, the other method is an organic titanate method, and the other method is a 4 method.
This is a functional silane method. (1) Sol coating and firing method A mixture of an anatase-type titanium oxide sol and silica sol is applied to the surface of a substrate by spray coating, dip coating, or the like.
It is applied by a coating method, a flow coating method, a spin coating method, a roll coating method, or the like, and baked. (2) Organic titanate method Titanium alkoxides (tetraethoxytitanium, tetramethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium, etc.), titanium acetate, titanium chelate, and other organic titanates are treated with a hydrolysis inhibitor (hydrochloric acid, Ethylamine, etc.) and silica sol are added, and alcohol (ethanol,
After diluting with a non-aqueous solvent such as propanol or butanol, etc. and then partially or completely allowing the hydrolysis to proceed, the mixture is spray-coated, dip-coated. Method, floating coating method,
It is applied by a method such as spin coating or roll coating, and dried. By drying, hydrolysis of the organic titanate is completed to produce titanium hydroxide, and a layer of amorphous titanium oxide is formed on the surface of the base material by dehydration-condensation polymerization of the titanium hydroxide. Thereafter, the amorphous titanium oxide is calcined at a temperature higher than the crystallization temperature of the anatase to cause a phase transition from the amorphous titanium oxide to the anatase titanium oxide. (3) Tetrafunctional silane method A mixture of tetraalkoxysilane (tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetramethoxysilane, etc.) and an anatase type titanium oxide sol is spray-coated on the surface of the substrate. Method, dip coating method, flow coating method, spin coating method, roll coating method, and the like, and if necessary, hydrolyze to form a silanol, and then heat, etc. The silanol is subjected to dehydration polycondensation by the method described above.

Next, the case where the surface layer is composed of a photocatalyst and a solid acid will be described with reference to the case where the photocatalyst is an anatase type titanium oxide and the solid acid is TiO ₂ / WO ₃ . In this case, a method of mixing an ammonia-dissolving solution of tungstic acid with an anatase-type titanium oxide sol and, if necessary, diluting the mixture with a diluting solution (water, ethanol, etc.) on the surface of the substrate is sprayed. Coating, dip coating, flow coating, spin coating, roll coating, etc. are applied and baked.

Next, the case where the surface layer is composed of a photocatalyst and a silicon oxide will be described by taking as an example the case where the photocatalyst is an anatase type titanium oxide. The method in this case is to mix an uncured or partially cured silicone or a silicone precursor paint with an anatase type titanium oxide sol, and to prepare the silicone precursor as necessary. After the hydrolysis, the mixture is sprayed on the surface of the substrate,
It is applied by a dip coating method, a flow coating method, a spin coating method, a roll coating method, or the like, and a hydrolysis product of a silicone precursor is subjected to dehydration condensation polymerization by a method such as heating. Then, a surface layer composed of anatase type titanium oxide particles and silicone is formed. In the formed surface layer, at least a part of the organic group bonded to the silicon atom in the silicone molecule is replaced with a hydroxyl group by photoexcitation of the anatase type titanium oxide by irradiation with light including ultraviolet rays, Furthermore, a physisorption water layer is formed on it,
It exhibits a high degree of hydrophilicity. Here, the precursors of silicone include methyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltributoxysilane, and ethyltripropoxysilane. , Phenyltrimethoxysilane, phenyltriethoxysilane, phenyltributoxysilane,
Phenyltripropoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldibutoxysilane, dimethyldipropoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldibutoxysilane, diethyldipropoxysilane, phenylmethyldimethoxysilane, phenylmethyl Diethoxysilane, phenylmethyldibutoxysilane, phenylmethyldipropoxysilane, γ-glycidoxypropyltrimethoxysilane, a hydrolyzate thereof, and a mixture thereof can be suitably used.

[0022]

EXAMPLE First, a primer paint (Toshiba Silicone, a paint obtained by diluting PH93 6 times with a toluene solvent) was applied to a 10 cm square painted steel sheet surface by a spray coating method and then dried at room temperature. Then, the substrate was covered with a primer-resin layer. Next, a silicone-based hard coating agent (Toshiba Silicone, Tosgard) is applied by a flow coating method, dried at 90 ° C. for 3 hours, and placed on the primer resin layer. A hard coat layer was formed. Further, the surface of the hard coat layer was treated with a corona surface treatment device (Kasuga Electric) using a wire electrode as an electrode, a gap of 2 mm between the electrode tip and the sample surface, a voltage of 26 kV, a frequency of 39 kHz, and a sample feed speed of 4.2 m. / Min under high frequency corona discharge treatment #
One sample was obtained. On the other hand, an anatase type titanium oxide sol 56
Parts by weight (Nissan Chemical, TA-15, average particle size 12 nm) and 33 parts by weight of silica sol (Nippon Synthetic Rubber, Glasca A liquid)
Was mixed and diluted with ethanol, and 11 parts by weight of methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B liquid) was further added to prepare a titanium oxide-containing coating composition. The above coating composition was applied to the # 1 sample by a flow coating method, heat-treated at 90 ° C. for 3 hours, and cured to obtain a # 2 sample. This # 2 sample was irradiated with ultraviolet light at an ultraviolet illuminance of 0.6 mW / cm ² for about 48 hours using an ultraviolet light source (Sankyo Electric Co., Ltd., Black Light Blue (BLB) fluorescent lamp) at an ultraviolet illuminance of 0.6 mW / cm ^2. I got For comparison, a 10 cm square stainless steel plate sample was also prepared. First, a water drop was dropped on the # 3 sample and the stainless steel plate sample, and the state after the drop was observed and the contact angle with water was measured. 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. As a result, when a water drop was dropped on the sample surface from the microsyringe in the # 3 sample, it was observed that the water droplet spread uniformly on the sample surface in the form of a water film. Further, the contact angle with water after 30 seconds was highly hydrophilized to about 0 °. On the other hand, in the case of a stainless steel plate sample, when a water drop was dropped on the sample surface from the microsyringe, the water droplet slightly adapted to the surface, but did not reach a uniform water film state. The contact angle with water after 30 seconds was 70 °.

[0023]

According to the present invention, in a railway vehicle, snow on the vehicle body is less likely to be permanently and non-uniformly generated, so that even in normal high-speed running, a falling stone caused by falling snow on the vehicle body can be prevented. .

[Brief description of the drawings]

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

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

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C09D 7/12 C09D 7/12 Z // B60S 1/00 B60S 1/00

Claims (7)

[Claims] 1. A stepping stone accident prevention property comprising: a surface layer containing photocatalyst particles on an outer surface of a vehicle, wherein the surface of the layer becomes hydrophilic in response to photoexcitation of the photocatalyst. Railway vehicles. 2. The stepping stone accident preventing railway vehicle according to claim 1, wherein the surface layer further contains silica. 3. The stepping stone accident preventing railway vehicle according to claim 1, wherein the surface layer further contains a solid acid. 4. The stepping stone accident preventing railway vehicle according to claim 1, wherein the surface layer further contains silicon. 5. The surface according to claim 1, wherein the surface of the surface layer exhibits hydrophilicity of 10 ° or less in terms of a contact angle with water in response to photoexcitation of the photocatalyst. Stepping stone accident prevention railway vehicle. 6. The surface according to claim 1, wherein the surface of the surface layer exhibits a hydrophilicity of 5 ° or less in terms of a contact angle with water in response to photoexcitation of the photocatalyst. Stepping stone accident prevention railway vehicle. 7. The method according to claim 1, wherein a protective layer capable of being made hydrophilic is further provided on the surface of the surface layer.
6. The stepping stone accident prevention railway vehicle according to 6.