WO2001068786A1

WO2001068786A1 - Hydrophilic member and method for manufacture thereof

Info

Publication number: WO2001068786A1
Application number: PCT/JP2001/001984
Authority: WO
Inventors: Masahiro Miyauchi; Mitsuhide Shimohigoshi; Kazuhito Hashimoto; Toshiya Watanabe
Original assignee: Toto Ltd.
Priority date: 2000-03-13
Filing date: 2001-03-13
Publication date: 2001-09-20
Also published as: JP5130603B2; AU4112401A

Abstract

A member which comprises a substrate and, formed on and jointed to the surface thereof, a surface layer comprising a titanium oxide and an amorphous tungsten oxide which have photocatalytic activity, wherein the titanium oxide and an amorphous tungsten oxide are jointed with each other without forming a solid solution, and wherein the uppermost surface of the surface layer exhibits a hydrophilicity of 10 degree or less in terms of a water contact angle in response to the optical pumping by the radiation of light of 10 νW/cm2 or less in terms of the illuminance of ultraviolet rays; and a method for manufacturing the member. The member is capable of exhibiting excellent hydrophilicity in response both to a weak light of an internal lighting level and sunlight, even with a small amount of photocatalyst, and thereby having the resistance to fogging and staining.

Description

Description Hydrophilic member and method for producing the same [Background of the invention]

Field of the invention

The present invention relates to a member having a hydrophilic surface, and more specifically, a member such as a mirror, a lens, a sheet glass, a building interior material, a building exterior material, and the like, for which antifogging property and antifouling property are required. And a method for producing the same.

Background technique

WO96 / 293375 discloses that the surface of a photocatalyst-containing layer formed on the surface of a substrate has a high degree of hydrophilicity (for example, in terms of a contact angle with water, depending on the photoexcitation of the photocatalyst). 10 ° or less). Utilizing this property, it is said that it is possible to improve the anti-fog and visibility enhancement of transparent members such as glass, lenses and mirrors, and to improve the water washing property and rainfall washing property of the article surface.

Then, it is desired that the hydrophilicity induced by the photocatalyst be expressed more efficiently.

On the other hand, the following is known as a prior art which discloses a combination of titanium oxide and tungsten oxide.

Japanese Patent Application Laid-Open No. 11-388867 discloses that the mixed metal oxide has a wavelength of 300 in the presence of a mixed metal oxide of titanium oxide and tungsten oxide, an oxidizable compound and a gas containing oxygen. It discloses a deodorization method using a photocatalyst that irradiates light having a maximum wavelength of not less than 370 nm and a wavelength of not more than 370 nm.

Japanese Patent Application Laid-Open No. 10-1141545 discloses a hydrophilic member having a surface layer containing photocatalytic titanium oxide and tungsten oxide formed on the surface of a substrate.

WO97 / 235772 discloses a substrate, a layer containing a photocatalyst formed on the surface of the substrate, and water molecules physically adsorbed on the surface of the layer in response to photoexcitation of the photocatalyst. a hydrophilic member comprising a layer, disclose that capable of carrying a T i 0 ₂ / W0 ₃ to the photocatalyst-containing layer surface. Japanese Patent Application Laid-Open No. H10-57871 discloses a photocatalyst structure having a photocatalyst layer on a substrate surface, wherein at least a part of the photocatalyst layer surface has a metal compound having a thickness of 0.2 to 10 O nm. A photocatalyst structure having a thin film is disclosed.

[Summary of the Invention]

The present inventors have recently suggested that the combination of photocatalytic titanium oxide and amorphous tungsten oxide can efficiently induce hydrophilicity with a photocatalyst even with a small amount of photocatalyst or a weak amount of ultraviolet light. Obtained knowledge.

Therefore, the present invention quickly develops excellent hydrophilicity in response to sunlight or weak light of the indoor lighting level even with a small amount of photocatalytic titanium oxide, thereby achieving antifogging and antifouling properties. It is an object of the present invention to provide a member capable of obtaining the above and a method for producing the same.

The member of the present invention comprises: a base material; and a surface layer bonded to the surface of the base material and containing a photocatalytic titanium oxide and an amorphous tungsten oxide.

The titanium oxide and the amorphous tungsten oxide are joined to each other without forming a solid solution; and

The outermost surface of the surface layer exhibits a hydrophilicity of 10 degrees or less in terms of water contact angle in response to light excitation by light irradiation of 10 〃W / cm ² or less in terms of ultraviolet illuminance. .

[Brief description of drawings]

FIG. 1 is a diagram illustrating a charge transfer process when both titanium oxide and tungsten oxide are photoexcited.

Figure 2 is a diagram explaining the charge transfer process when tungsten oxide is photoexcited.

FIG. 3 is a diagram illustrating a charge transfer process when photocatalytic titanium oxide is photoexcited.

FIG. 4 is a conceptual diagram showing a cross section of a member according to the first embodiment of the present invention.

FIG. 5 is a conceptual diagram showing a cross section of a member according to the second embodiment of the present invention.

FIG. 6 is a conceptual diagram showing a cross section of a member according to the third embodiment of the present invention. FIG. 7 is a conceptual diagram showing a cross section of a member according to the fourth embodiment of the present invention.

FIG. 8 is a conceptual diagram showing a cross section of a member according to the fifth embodiment of the present invention.

FIG. 9 is a conceptual diagram showing a cross section of a member according to the sixth embodiment of the present invention.

FIG. 10 is a conceptual diagram showing a cross section of a member according to the seventh embodiment of the present invention.

FIG. 11 is a conceptual diagram showing a cross section of a member according to the eighth embodiment of the present invention.

FIG. 12 is a diagram showing the relationship between the contact angle with water on the sample surface and the light irradiation time when the UV illuminance is 10 W / cm ² in Example A1.

FIG. 13 is a diagram showing the relationship between the contact angle with water on the sample surface and the light irradiation time when the ultraviolet illuminance is 3 zW / cm ² in Example A1.

FIG. 14 is a diagram showing the relationship between the contact angle of the sample surface with water and the light irradiation time in Example A2.

FIG. 15 is a diagram showing the relationship between the contact angle of the sample surface with water and the light irradiation time in Example A3.

FIG. 16 is a diagram showing the relationship between the contact angle of the sample surface with water and the light irradiation time in Example A4.

FIG. 17 is a diagram showing the relationship between the contact angle of the sample surface with water and the light irradiation time in Example A5.

FIG. 18 is a diagram showing the relationship between the contact angle of the sample surface with water and the storage time at a location in Example A6.

FIG. 19 is a diagram showing the relationship between the rate of hydrophilicity conversion and the ratio of the tungsten raw material to the solid content in the raw material solution in Example B1.

FIG. 20 is a diagram showing the relationship between the rate of hydrophilicity constant and the proportion of the tungsten raw material occupying the solid content in the raw material solution in Example B2.

FIG. 21 is a diagram showing the relationship between the rate of hydrophilicity constant and the ratio of the tungsten raw material to the solid content in the raw material solution in Example B3.

[Specific description of the invention]

Hydrophilic member

The member of the present invention has a base material and a surface layer bonded to the surface of the base material. (a) Substrate

The substrate used in the present invention can be a metal, an inorganic material, an organic material, and a composite thereof. Specific examples include tiles, sanitary ware, tableware, calcium silicate plates, cement extruded plates, ceramic substrates, new ceramics such as semiconductors, insulators, glass, mirrors, wood, and resins. In addition, examples of the base material when expressed as the use of the member include building exterior materials, building interior materials, window frames, window glass, structural members, vehicle exteriors, dustproof covers for articles, traffic signs, various display devices , Advertising towers, road noise barriers, railway noise barriers, bridges, guardrails, tunnel interiors and coatings, insulators, solar battery covers, solar water heater collector covers, plastic greenhouses, vehicle lighting covers, housing Equipment, toilets, bathtubs, wash basins, lighting fixtures, lighting covers, kitchen utensils, dishwashers, dish dryers, sinks, cooking ranges, kitchen hoods, ventilation fans, protective films, etc.

(b) Surface layer

In the present invention, the surface layer contains photocatalytic titanium oxide and amorphous tungsten oxide. The titanium oxide and the amorphous tungsten oxide are bonded to each other without forming a solid solution. Conventionally, a combination of photocatalytic titanium oxide and tungsten oxide has been known. However, to the knowledge of the present inventors, there is no disclosure of an amorphous tungsten oxide that is bonded without forming a solid solution with titanium oxide. In the prior art known to the present inventors, it is only suggested that the tungsten oxide is crystallized or forms a solid solution with the titanium oxide and is bonded thereto.

The surface layer of the member according to the present invention is excellent in hydrophilization efficiency. As a result, there is an excellent advantage that the hydrophilicity can be efficiently induced by the photocatalyst even with a small amount of the photocatalyst or a small amount of the ultraviolet light. Specifically, in the presence of 5 0 g Z cm ² of about or less of titanium oxide as a photocatalyst, and 1 0 W / cm ² even following UV illumination efficiently hydrophilized. Further, since the amount of titanium oxide as a photocatalyst can be reduced, high transparency can be realized without causing iris or cloudiness on the surface layer.

The reason why such highly efficient hydrophilization can be obtained is not clear, but is expected as follows: Is done. However, the following theory is only expected, and the present invention is not limited to this theory. If the titanium oxide and the amorphous tungsten oxide are bonded to each other without forming a solid solution, when light is irradiated, charge transfer occurs at this bonded portion, improving charge separation efficiency and improving hydrophilicity. Is thought to contribute to the expression of More specifically, it is as follows.

The band gap of amorphous tungsten oxide is 3.2 leV, which is narrower than the band gap of titanium oxide 3.2 eV. In addition, the potential at the lower end of the conduction band of amorphous tungsten oxide is more positive than 0 V in terms of the standard hydrogen electrode potential when pH = 7, and the potential at the upper end of the valence band is Is more positive than +2.7 V in terms of standard hydrogen electrode potential when pH = 7. Accordingly, the amorphous oxide evening tungsten is, _c upper end of the lower end and the valence band of the conduction band is on the positive side of the titanium oxide When bonding the two materials in such a case occurs in the conduction band by photoexcitation If the free energy of the cast decreases, the electrons generated and the holes generated in the valence band can move between different types of photocatalysts, which may promote charge separation. Here, if a solid solution is formed between the titanium oxide and the tungsten oxide, an impurity level is generated between the titanium oxide and the tungsten oxide. It is thought that the impurity level acts as a recombination center between the photoexcited electron and the hole and hinders the hydrophilization reaction.

This point will be described in detail with reference to the drawings. Figure 1 shows the energy structures of titanium oxide and tungsten oxide. Here, when light is applied to excite both titanium oxide and tungsten oxide, electrons generated in the conduction band of titanium oxide move to the conduction band of the tungsten oxide material, and are generated in the valence band of tungsten oxide. The holes can move to the valence band of titanium oxide. The holes transferred to the titanium oxide react with the lattice oxygen of the titanium oxide itself to generate oxygen vacancies with high affinity for water and become hydrophilic, while the electrons transferred to the tungsten oxide are oxygen in the air. Reacts with to generate superoxodonion and is released to the outside world. It is thought that the holes generated in tungsten oxide act effectively on the surface of the titanium oxide to make it hydrophilic, and assist this.

On the other hand, Fig. 2 shows the irradiation of visible light with a wavelength of 400 nm or more, which makes it difficult to excite titanium oxide. FIG. Titanium oxide cannot be excited by visible light with a wavelength of 400 nm or more, but can excite tungsten oxide. The holes generated by the tungsten oxide move to the titanium oxide side. It is considered that the probability of recombination is extremely low due to the separation of the electron-hole pairs, and that the surface of the titanium oxide particles is promoted to be hydrophilic.

FIG. 3 shows a case where light for exciting only titanium oxide is irradiated. Even in this case, it is considered that the generated holes are efficiently collected on the titanium oxide without recombination with the electrons, and the hydrophilicity of the titanium oxide is promoted.

In the present invention, preferable crystal structures of titanium oxide include an analog type, a rutile type, and a wurtzite type.

In the present invention, the amorphous tungsten oxide means not only so-called amorphous tungsten oxide but also tungstic acid or a salt thereof. Further, it may be a mixture of amorphous tungsten oxide and tungstic acid or a salt thereof. Preferred examples of the tungstate include ammonium salt, hydrochloric acid salt, nitrate, nitrate, organic acid salt, alcoholate, chelate, acetate and the like.

Further, according to a preferred aspect of the present invention, it is preferable that both or either of the titanium oxide and the amorphous tungsten have a particle shape. According to a preferred embodiment of the present invention, the particle size of the titanium oxide particles is preferably about 1 to 5 O nm, more preferably about 5 to 30 nm. The particle size of the tungsten oxide is preferably 50 nm or less, more preferably about 5 to 3 O nm.

Further, according to a preferred aspect of the present invention, it is preferable that the titanium oxide is present on the outermost surface of the surface layer in a state where the titanium oxide can come into contact with moisture in the outside air.

According to a preferred embodiment of the present invention, the tungsten oxide preferably has oxygen vacancies.

According to a preferred embodiment of the present invention, the ratio of tungsten oxide atoms: titanium atoms on the surface of the surface layer is 0.005 to 0.50 in terms of a value measured by X-ray photoelectron spectroscopy. : 0.995-0.50.

Further, according to another preferred aspect of the present invention, the oxidized ring in the surface layer. The proportion of stainless steel is preferably from 0.1% to 70% by weight, more preferably from 5% to 50%. By being in such a range, hydrophilicity can be induced more efficiently.

According to a preferred aspect of the present invention, it is preferable that the surface layer comprises a layer made of the titanium oxide and an amorphous tungsten oxide dispersed and scattered on the surface of the titanium oxide layer. That is, it is preferable that the tungsten oxide is scattered like islands on the layer made of titanium oxide. It should be noted that specific examples of this aspect include the first to fourth aspects of the present invention described below.

According to another preferred embodiment of the present invention, the surface layer includes the titanium oxide particles and the tungsten oxide particles in a mixed form. Also in this case, it is preferable that the titanium oxide exists on the outermost surface of the surface layer in a state where the titanium oxide can come into contact with moisture in the outside air. Specific examples of this aspect include the fifth to eighth aspects of the present invention described below.

According to a preferred embodiment of the present invention, it is preferable that the surface layer further includes a metal oxide having at least one bond selected from the group consisting of a siloxane bond, a porosiloxane bond, and an aluminosilicate bond (hereinafter, referred to as a “metal oxide”). However, in the present specification, simply referring to a metal oxide means the metal oxide). These compounds have the property of being able to adsorb a large amount of chemically adsorbed water, so that the efficiency of inducing hydrophilicity is improved. Is advantageous. Specific examples of such a metal oxide include silica, silicone, alkyl silicate, alkali silicate, and acrylic silicon.

The metal oxide may be dispersed and scattered on the surface layer. According to a preferred embodiment of the present invention, the metal oxide may be present as a layer on the surface of the surface layer. In this case, the hydrophilicity appears at the resurface of this metal oxide layer. The metal oxide layer preferably has a thickness of about 1 nm to about 100 nm from the viewpoint of maintaining hydrophilicity. In some cases, it is preferable that the metal oxide layer has open pores from the viewpoint of developing the hydrophilicity of titanium oxide. (c) Light irradiation

Surface layer in the present invention, in terms of ultraviolet intensity 1 0 zW / cm ² or less, rather preferably below 3〃 W / cm ^z, more preferably corresponding to excitation by light irradiation less than 1〃 W / cm ^z The outermost surface exhibits a hydrophilicity of 10 degrees or less, preferably 5 degrees or less, more preferably 3 degrees or less in terms of a water contact angle. Even when irradiated with fine weakly fluorescent lamps 1 iW / cm ^z in terms of UV illumination, very advantageous that the surface is capable of highly hydrophilic to less than 5 degrees in terms of water contact angle It is. That is, indoors generally have a small amount of ultraviolet rays. Even in such an environment, as a result of achieving a high degree of hydrophilicity, the effects of anti-fog, drip-proof, and self-purification can be expected indoors.

Further, according to a preferred aspect of the present invention, it is preferable that the irradiated light be a light having a wavelength that can excite both titanium oxide and tungsten oxide. Specifically, light having a wavelength in the range of 30 O nm to 450 nm can be suitably used to excite titanium oxide and tungsten oxide. In general, when sunlight from the outdoors is blocked, the light emitted from fluorescent lamps and incandescent lamps to the articles installed on the indoor wall has a wavelength of 300 nm to 450 nm. The integrated illuminance of the area is estimated to be 0.1 to 10 1W / cm ² . In this respect too, the component according to the invention is advantageous for indoor use. Use of parts

The surface of the component according to the invention is highly hydrophilic. As a result, the attached water does not become water droplets but spreads as a thin water film. As a result, the component according to the invention has application as a non-fogging or anti-fog component.

Furthermore, due to the high hydrophilicity, dirt components adhering to the substrate surface can be easily removed by flowing water. Therefore, the member according to the present invention is a member that is hardly soiled. Furthermore, for example, when the member according to the present invention is installed outdoors, if it adheres, it has an advantageous property that it is easily washed away by rainfall or the like, that is, it is self-cleaning (self-cleaning).

In addition, since the surface layer of the member according to the present invention is substantially transparent and has no interference color, the design property of any article of architectural exterior materials, interior materials and other indoor members may not be impaired. It is also advantageous in that it does not have any.

It should be noted that the hydrophilic member of the present invention emits light from a mercury lamp, a xenon lamp, a mercury-xenon lamp, a halogen lamp, a metal halide lamp, etc., which has a high light intensity, and sunlight and sunlight scattered from a window. It is needless to say that even when the photo-excitation is performed, the anti-fogging, anti-fouling, and self-cleaning effects as described above are exhibited. Production method

The method for manufacturing a member according to the present invention will be described below.

The first manufacturing method according to the present invention is to form a two-layer surface layer composed of a titanium oxide layer and an amorphous tungsten oxide layer on the surface of a base material. That is, the first production method of the present invention comprises:

(a) forming a titanium oxide layer containing photocatalytic titanium oxide particles on a substrate surface;

(b) forming a layer comprising amorphous tungsten oxide and / or a precursor thereof on the surface of the titanium oxide layer;

(c) heat-treating the substrate surface at a temperature at which the titanium oxide and the amorphous tungsten oxide do not form a solid solution. The temperature at which a solid solution is not formed is preferably lower than 500 ° C, more preferably in the range of 20 ° C to 350 ° C.

In the second production method according to the present invention, a surface layer containing titanium oxide and tungsten oxide in a mixed form is formed on the surface of a base material. That is, the second production method of the present invention comprises:

(a) A liquid obtained by mixing a liquid containing a photocatalytic titanium oxide and / or a precursor thereof and a liquid containing an amorphous tungsten oxide and / or a precursor thereof on a substrate surface. Applying a single composition,

(b) a step of heat-treating the surface of the substrate coated with the composition at a temperature at which titanium oxide and tungsten oxide do not form a solid solution. The temperature at which a solid solution is not formed may be the same as the temperature according to the first production method described above. In both the first and second production methods, photocatalytic titanium oxide or a precursor thereof is used. Preferred examples of the precursor of the photocatalytic titanium oxide include amorphous titania sol, crystalline titania sol, tetramethyltitanium, tetraethoxytitanium, tetraisopropoxytitanium, tetran-propoxytitanium, tetrabutoxytitanium, titanium chelate, a The raw material includes at least one selected from the group consisting of cetylacetone titanium, titanium tetrachloride, titanium sulfate, and titanium hydroxide.

The precursors of the amorphous tungsten oxide include ammonium tungstate, tungstic acid, a sol in which amorphous tungsten oxide particles are suspended, penethoxyethoxytungsten, pentamethoxytungsten, pengupropoxytungsten, pen Examples include those containing at least one tungsten compound selected from the group consisting of butoxytungsten, tungsten chelate, acetate tungsten, tungsten sulfate, tungsten chloride, and tungsten hydroxide. As a method for applying the coating composition in the production method according to the present invention, subbing coating, flow coating, dip coating, spray coating, roll coating and the like can be suitably used. For example, when the spin coating method is selected as the method for applying the coating composition, the thickness of the coating can be controlled by the rotation speed of the base material and the concentration of the raw material solution.

Further, according to another preferred embodiment of the present invention, any of a titanium oxide layer and an amorphous tungsten oxide layer, or a surface layer containing titanium oxide and tungsten oxide in a mixed form, is formed by sputtering, CVD, or the like. , A plasma CVD method, an ion plating method, an MBE method, or the like.

Preferred embodiments of the member of the present invention and a method for producing the same will be described more specifically.

Member according to the first aspect

In the member according to the first embodiment of the present invention, as shown in FIG. 4, a layer 12 containing titanium oxide is formed on a substrate 10, and an island 14 made of tungsten oxide is formed on the layer 12. It is bonded to a layer 12 containing titanium oxide. At least a part of the titanium oxide is exposed to the outside air, and is capable of coming into contact with moisture in the outside air. The member according to the first embodiment can be manufactured as follows. First, a starting material of titanium oxide is applied to a substrate, and then a thin film of titanium oxide is formed by drying or baking. Further, after the starting material of tungsten oxide is applied on the titanium oxide thin film, drying or heating is performed.

Member according to the second aspect

As shown in FIG. 5, the member according to the second embodiment of the present invention maintains the surface hydrophilicity in a dark place or strengthens it. 6 may be formed.

The member according to the second embodiment can be manufactured, for example, as follows. First, a starting material of titanium oxide is applied to a substrate, and then a thin film of titanium oxide is formed by drying or baking. Further, a coating agent containing a starting material of tungsten oxide and a starting material of metal oxide is applied on the titanium oxide thin film and then dried or baked. Further, after forming the titanium oxide thin film, the starting material of tungsten oxide may be applied, followed by drying or baking, and then the starting material of the metal oxide may be applied, followed by drying or baking. After forming the titanium oxide thin film, the starting material of the metal oxide may be applied, followed by drying or baking, and then the starting material of tungsten oxide may be applied, followed by drying or baking.

Member according to the third aspect

In the member according to the third embodiment of the present invention, as shown in FIG. 6, a layer 32 containing titanium oxide is formed on a base material 30, and an island 34 made of tungsten oxide is bonded thereon. Further, a layer 36 made of a metal oxide is formed thereon.

The member according to the fourth aspect can be manufactured, for example, as follows. First, a starting material of titanium oxide is applied to a substrate, and then a thin film of titanium oxide is formed by drying or baking. Further, after the starting material of tungsten oxide is applied on the titanium oxide thin film, drying or baking is performed. After that, the starting material containing a metal oxide is applied thereon, and then drying or baking is performed.

Member according to fourth aspect

The member according to the fourth embodiment of the present invention, as shown in FIG. A mixed layer 42 containing a metal oxide capable of adsorbing more chemically adsorbed water than tan and titanium oxide is formed, and an island 44 made of tungsten oxide is further joined to the mixed layer 42. .

The member according to the fourth embodiment can be manufactured, for example, as follows. First, a coating agent containing a starting material of titanium oxide and a starting material of metal oxide is applied to a substrate, and then a mixed layer containing titanium oxide and a metal oxide is formed by drying or baking. Further, a tungsten oxide starting material is applied on the mixed layer, and then dried or heated and baked.

Member according to fifth aspect

In the member according to the fifth embodiment of the present invention, as shown in FIG. 8, a coating 52 made of titanium oxide particles and tungsten oxide particles is formed on a base material 50. At least a portion of the titanium oxide particles and at least a portion of the tungsten oxide particles are joined without forming a solid solution, and at least a portion of the titanium oxide particles are exposed to the open air. The member according to the fifth embodiment, which is exposed and can come into contact with moisture in the outside air, can be manufactured, for example, as follows. First, a coating agent containing a starting material of titanium oxide and a starting material of tungsten oxide is applied to a substrate. Then, dry or heat bake.

Member according to the sixth aspect

In the member according to the sixth embodiment of the present invention, as shown in FIG. 9, a mixed film 62 formed by adding a metal oxide to titanium oxide and tungsten oxide is formed on a base material 60. ing.

The member according to the sixth aspect can be manufactured, for example, as follows. First, a coating material containing a starting material of titanium oxide, a starting material of tungsten oxide, and a starting material of metal oxide is applied to a substrate. Then, dry or heat bake.

Member according to the seventh aspect

As shown in FIG. 10, the member according to the seventh embodiment of the present invention includes a bird film made of metal oxide on a film 72 made of titanium oxide and tungsten oxide formed on a base material 70. 7 4 are formed. The member according to the seventh aspect can be manufactured, for example, as follows. First, a coating agent containing a starting material of titanium oxide and a starting material of tungsten oxide is applied to a substrate, and then a mixed film of titanium oxide and tungsten oxide is formed by drying or baking. Further, a starting material containing a metal oxide is applied on the mixed film, and then dried or baked.

Member according to the eighth aspect

As shown in FIG. 11, the member according to the first embodiment of the present invention has a film 82 made of titanium oxide and tungsten oxide formed on a base material 80, and a layer made of a metal oxide formed thereon. 8 4 are formed.

The member according to the eighth aspect can be manufactured in the same manner as the member according to the seventh aspect. At this time, the thickness of the layer made of the metal oxide can be controlled by adjusting the concentration of the starting material containing the metal oxide. Antifogging method and antifouling method

According to another aspect of the present invention, there is provided a method for imparting anti-fog properties to a member surface. This method comprises providing a substrate with a surface layer comprising photocatalytic titanium oxide and amorphous tungsten oxide, wherein the titanium oxide and the amorphous tungsten oxide do not form a solid solution. They are joined together. By irradiating this base material with light of 10〃W / cm ² or less in terms of ultraviolet illuminance and photo-excitation, the member exhibits antifogging properties.

According to still another aspect of the present invention, there is provided a method for imparting antifouling property to a member surface. This method comprises providing a surface layer comprising a photocatalytic titanium oxide and an amorphous tungsten oxide on a base material, wherein the titanium oxide and the amorphous tungsten oxide form a solid solution without forming a solid solution. Be joined. By irradiating the substrate with light of 10 W / cm ² or less in terms of ultraviolet illuminance and photo-excitation, the member exhibits antifouling properties. The surface of this member is easily cleaned only by occasional contact with running water. JP01 / 01984

14

[Example]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example A 1

A titanium oxide coating agent (Nippon Soda, NDH510C) having a solid concentration of 10% was applied to silica-coated glass by dip coating. The dip coating was performed at a pulling speed of 15 cm / min. Then, the coated film was baked at 500 ° (:, 30 minutes) in an electric furnace. The above steps were repeated twice to produce a photocatalytic titanium oxide thin film having a thickness of about 20 Onm.

A liquid in which tungstic acid was dissolved in 25% aqueous ammonia was further coated on the thin film by spin coating. Spin coating was performed at a rotation speed of 1500 revolutions per minute for 10 seconds. Thereafter, the thin film was fired in an electric furnace at 300 ° C for 30 minutes. By changing the concentration of tungstic acid, samples with different loading amounts of photocatalytic tungsten oxide on titanium oxide were obtained. Sample # 1: no tungstic acid coating, Sample # 2: tungstic acid concentration 0.5% by weight (solid content, same hereafter), Sample # 3: tungstic acid concentration 1.0% by weight, And Sample # 4: evening stainless acid concentration was 2.0% by weight.

The ratio of tungsten atoms: titanium atoms on the surface of the thin film was measured by X-ray photoelectron spectroscopy. as a result,

Sample # 1 is 0: 1.00,

Sample # 2 was 0.10: 0.90,

Sample # 3 is 0.20: 0.80, and

Sample # 4 was 0.40: 0.60.

X-ray diffraction confirmed the presence of amorphous photocatalytic tungsten oxide on the surface of the thin film.

When the structure of the thin film surface was observed with an atomic force microscope, the surfaces of sample # 2, sample # 3, and sample # 4 were almost the same as the surface of sample # 1. These results suggested a structure composed of a layer made of titanium oxide and amorphous tungsten oxide dispersed on the surface of the titanium oxide layer and scattered in stripes. The obtained thin film was stored in a dark place until the surface contact angle with water became stable. Thereafter, the thin film was irradiated with a white fluorescent lamp, and the change in the contact angle with water on the surface was measured. As the white fluorescent lamp, 10 W (Toshiba Lighting & Technology, FL 10N) was used. Ultraviolet illuminance on the surface of the thin film was measured with an ultraviolet illuminometer (Shisho Electric, UVR-2), and the distance between the thin film and the fluorescent lamp was changed to 10 W / cm ² or 3 / W / cii. A drop of water was dropped from the microsyringe, and the contact angle with water was measured with a contact angle measuring instrument (Kyowa Interface Science, CA-X150).

Results when ultraviolet illuminance of 10 zW / cm ² was as shown in Figure 1 2. Sample # 1 was hydrophilized at 12 degrees in terms of the contact angle with water, and samples # 2 to # 4 were further hydrophilized to 0 °.

The ultraviolet illumination results for 3 W / cm ^sigma is been filed in as shown in Figure 13. Sample # 1 hardly hydrophilized, whereas Sample # 2 and Sample # 3 hydrophilized to less than 5 degrees. Sample # 4 had a slightly lower hydrophilization rate, but hydrophilized up to 8 degrees. Example A 2

In the same manner as in Example A1, a photocatalytic titanium oxide thin film having a thickness of about 200 nm was produced.

A liquid in which tungstic acid was dissolved in 25% aqueous ammonia was further coated on the thin film by spin coating (1,500 rpm for 10 minutes). Thereafter, the thin film was fired in an electric furnace at 100 ° C for 30 minutes. By changing the concentration of tungstic acid, samples having different amounts of photocatalytic tungsten oxide on titanium oxide were obtained. Sample # 5: no coating of tungstic acid; Sample # 6: dungstenic acid concentration 1.0% by weight (solid content, the same applies hereinafter); Sample # 7: tungstic acid concentration 2.0% by weight; Sample # 8: tungstic acid concentration was 5.0% by weight.

Sample # 5 is 0: 1.00,

For sample # 6, 0.20: 0.80, For sample # 7, 0.40: 0.60, and

Sample # 8 was 1.00: 0.

X-ray diffraction confirmed the presence of ammonium tungstate on the surface of the thin film. When the surface texture was observed with an atomic force microscope, the surfaces of Samples # 6 and # 7 were almost the same as the surface of Sample # 5. These results suggested a structure composed of a layer made of titanium oxide and amorphous tungsten oxide dispersed on the surface of the titanium oxide layer and scattered in stripes.

On the other hand, on the surface of sample # 8, a structure in which ammonium tungstate completely covered titanium oxide was observed.

The contact angle of the obtained thin film was measured in the same manner as in Example A1. However, the UV illuminance was set to 10〃W / cm ² . The results were as shown in FIG. Sample # 5 was hydrophilized to about 10 degrees, and samples # 6 and # 7 were further hydrophilized to 0 degrees. Example A 3

A 25% aqueous ammonia solution having a tungstic acid concentration of 1.0% by weight (solid content) was further coated on the thin film by spin coating (1,500 rotations per minute, 10 seconds). Thereafter, the thin film was baked for 30 minutes in an electric furnace while changing the temperature as follows.

Sample # 9: Not coated with tungstic acid (no firing)

Sample # 10: 100 ° C

Sample # 11: 300 ° C

Sample # 12: 350 ° C

Sample # 13: 500 ° C

The state of tungstic acid present on the surface of the thin film was observed by X-ray diffraction. As a result, the presence of ammonium tungstate in sample # 10, the presence of amorphous tungsten oxide in sample # 11, the presence of a composite phase of amorphous tungsten oxide and crystallized tungsten oxide in sample # 12, and the presence of crystallized tungsten oxide in sample # 13 . The ratio of tungsten atoms: titanium atoms on the thin film surface was measured by X-ray photoelectron spectroscopy. As a result, the ratio of sample # 9 was 0: 1.00, and the ratio of samples # 10 to # 13 was 0.20: 0.80.

When the surface texture was observed with an atomic force microscope, the surfaces of samples # 10 to # 13 were almost the same as the surface of sample # 9. From these results, the contact angle of the obtained thin film was measured in the same manner as in Example A1. However, the UV illuminance was 3 W / cm ² . The result was as shown in FIG. As a result, the hydrophilization rate of samples # 10 to # 13 was higher than that of sample # 9. In addition, sample # 10 had the largest hydrophilization rate, followed by samples # 11, # 12, and # 13. Example A 4

Aqueous titanium oxide sol (Ishihara STS21) was diluted with pure water until the solid content became 8%, and applied to silica-coated glass by spin coating (1500 rpm, 10 seconds). Thereafter, the coating film was fired in a Matsufuru furnace at 500 ° C for 30 minutes.

A 25% aqueous ammonia solution having a tungstic acid concentration of 1.0% by weight was further coated on the thin film by spin coating (at a rotation speed of 1500 rpm for 10 seconds). Thereafter, the thin film was baked for 30 minutes in an electric furnace while changing the temperature as follows.

Sample # 14: Not coated with tungstic acid (no firing)

Sample # 15: 100 ° C

Sample # 16: 300 ° C

The state of tungstic acid present on the surface of the thin film was observed by X-ray diffraction. As a result, the presence of ammonium tungstate in sample # 15 and the presence of amorphous tungsten oxide in sample # 16 were confirmed.

The ratio of tungsten atoms: titanium atoms on the thin film surface was measured by X-ray photoelectron spectroscopy. As a result, Sample # 14 had a ratio of 0: 1.00, and Samples # 15 and # 16 had a ratio of 0.20: 0.80. When the structure of the thin film surface was observed with an atomic force microscope, the surfaces of the samples # 15 and # 16 had almost no difference from the sample # 14. The results suggested a structure composed of a layer made of titanium oxide and amorphous tungsten oxide dispersed on the surface of the titanium oxide layer and scattered in stripes.

The contact angle of the obtained thin film was measured in the same manner as in Example A1. However, the UV illuminance was 1 / W / cm ² . The results were as shown in Figure 16. Sample # 14 was hydrophilized to 10 degrees, while samples # 15 and # 16 were further hydrophilized to 1 degree. Example A 5

A photocatalytic antifogging film containing photocatalytic titanium oxide and silica (Tohoku Kiki, Hydrotech Mira Film) was attached to the glass, and on top of this, an evening stainless acid concentration of 1.0% by weight. Was coated by spin coating (150 rpm / min, 10 seconds) and dried at 100 ° C. for 30 minutes.

X-ray diffraction confirmed the presence of ammonium tungstate on the surface of the thin film. According to X-ray photoelectron spectroscopy, the ratio of tungsten atoms: titanium atoms on the surface of the thin film was 0.20: 0.80.

When the structure of the thin film surface was observed with an atomic force microscope, the same structure as that of the film not coated with ammonium tungstate was observed. The results suggested a structure composed of a layer composed of titanium oxide and amorphous tungsten oxide dispersed on the surface of the titanium oxide layer and scattered in stripes.

The contact angle of the obtained thin film was measured in the same manner as in Example A1. However, the UV illuminance was set to 10 W / cm ² . The results were as shown in FIG. Example A 6

A 25% aqueous ammonia solution having a tungstic acid concentration of 1.0% by weight was further coated on the thin film by spin coating (1500 rotations per minute, 10 seconds). Then, the thin film was baked for 30 minutes in an electric furnace while changing the temperature as follows. .

Furthermore, a film of colloidal silica (Nissan Chemical, ST-OS) diluted with pure water to a solid concentration of 0.05% is spin-coated (1,500 revolutions per minute, 10 seconds) on this thin film. did. The obtained film was dried in an electric furnace at 150 ° C for 30 minutes.

X-ray photoelectron spectroscopy was used to measure the ratio of tungsten: silicon: titanium on the surface of the thin film. As a result, it was 0.20: 0.40: 0.40.

X-ray diffraction confirmed the presence of amorphous tungsten oxide.

The prepared thin film was irradiated with fluorescent light, and then stored in a clean dark place. The contact angle with water at that time was measured according to Example A1. The results were as shown in Figure 18. During the long-term even 1000 hours, _c Example B 1 that remained 5 degrees or less hydrophilic

An aqueous titanium oxide sol (NTB-21, manufactured by Showa Denko KK) and an aqueous solution of ammonium tungstate were mixed at the following concentrations to obtain a coating solution having a solid concentration of 2% by weight for these components. That is, coating solutions were prepared in which the weight ratio of ammonium tungstate to titanium oxide was 5%, 10%, 20%, 30%, 40%, 50%, 70%, and 90%. This coating solution was applied to silica-coated glass by spin coating (1,500 revolutions per minute, 10 seconds), followed by baking at 300 ° C for 30 minutes in a Matsufur furnace.

The obtained glass member having a thin film on the surface was substantially transparent without cloudiness or iris color.

X-ray diffraction confirmed the presence of a mixed phase of amorphous tungsten oxide and ananases-type titanium oxide on the surface of the thin film.

In addition, the lattice constant of titanium oxide obtained from the results of X-ray diffraction was similar to the literature value of stoichiometric titanium oxide. This suggested that no solid solution was generated between titanium oxide and tungsten oxide.

The contact angle of the obtained thin film was measured in the same manner as in Example A1. However, the UV illuminance was 5 / W / cm ² . From the obtained value of the contact angle, a hydrophilization rate constant was determined according to the following equation. Empirically, the change in contact angle during light irradiation is expressed by a secondary reaction equation as shown in equation (1). Obey. That is, when the reciprocal of the contact angle 0 is plotted against time, a linear relationship is obtained, and this slope can be defined as a hydrophilization rate constant.

<Θ: contact angle with water, t: irradiation time, _α : hydrophilic constant)

Further, the relationship between the hydrophilization rate constant obtained according to the equation (1) and the ratio of the tungsten raw material to the solid content in the coating liquid is shown in FIG. From these results, it can be seen that when the proportion of the tungsten raw material is in the range of 5 to 50%, it is most advantageous for promoting the hydrophilization. It should be noted that when the proportion of the tungsten raw material was in the range of 5 to 50%, the material was hydrophilized to 5 degrees or less. Example Β 2

A glass member was obtained in the same manner as in Example 2. However, the firing temperature in the Matsufuru furnace was 100 ° C.

X-ray diffraction confirmed the presence of a mixed phase of ammonium tungstate and an anatase-type titanium oxide on the surface of the thin film.

The lattice constant of titanium oxide obtained from the results of X-ray diffraction is

-The value was similar to the literature value of zeolite titanium oxide. This suggested that no solid solution was generated between titanium oxide and tungsten oxide.

The contact angle of the obtained thin film was measured in the same manner as in Example A1. However, the UV illuminance was 5 W / cm ² . From the value of the obtained contact angle, a hydrophilization rate constant was obtained from the equation (1) in the same manner as in Example B1. FIG. 20 shows the relationship between the rate constant of hydrophilization and the ratio of the tungsten raw material to the solid content in the coating solution. From these results, it is most advantageous to promote the hydrophilization when the proportion of the tungsten raw material is in the range of 5 to 50%. It turns out that it is. It should be noted that when the proportion of the tungsten raw material was in the range of 5 to 50%, the material became hydrophilic to 5 degrees or less. Example B 3

A glass member having a thin film on the surface was obtained in the same manner as in Example B1, except that the aqueous titanium oxide sol was changed to A-6, manufactured by Taki Kagaku.

X-ray diffraction confirmed the presence of a mixed phase of amorphous tungsten oxide and ana-type titanium oxide on the thin film surface.

In addition, the lattice constant of titanium oxide obtained from the results of X-ray diffraction showed a value similar to the literature value of anatomical titanium oxide in stoichiometry. This suggested that no solid solution was generated between titanium oxide and tungsten oxide.

The contact angle of the obtained thin film was measured in the same manner as in Example A1. However, the UV illuminance was 5 zW / cm ² . From the value of the obtained contact angle, a hydrophilization rate constant was obtained from the equation (1) in the same manner as in Example B1. Figure 21 shows the relationship between the rate constant of hydrophilization and the ratio of the tungsten raw material to the solid content in the coating solution. From this result, it can be seen that when the proportion of the tungsten raw material is in the range of 5 to 40%, it is most advantageous for promoting the hydrophilization.

Claims

The scope of the claims

1. The substrate and

A surface layer comprising a photocatalytic titanium oxide and an amorphous tungsten oxide bonded to the surface of the base material,

In terms of UV irradiance in response to photoexcitation by following light irradiation 1 0〃W / cm ^z, exhibits 1 0 degrees or less hydrophilic outermost surface prior Symbol surface layer in terms of water contact angle, member.

2. The member according to claim 1, wherein the amorphous tungsten oxide is tungstic acid or a salt thereof.

3. The member according to claim 2, wherein the tungstate is ammonium tungstate.

4. The member according to any one of claims 1 to 3, wherein the titanium oxide has a particle shape.

5. The member according to any one of claims 1 to 4, wherein the amorphous tungsten oxide has a particle shape.

6. The member according to any one of claims 1 to 5, wherein the titanium oxide and the amorphous tungsten oxide are hetero-bonded without generating an impurity level.

7. The member according to any one of claims 1 to 6, wherein the surface layer comprises a layer made of the titanium oxide, and an amorphous tungsten oxide dispersed and scattered on the surface of the titanium oxide layer. .

8. The member according to any one of claims 1 to 6, wherein the surface layer comprises the titanium oxide and the amorphous tungsten oxide in a mixed form.

9. The member according to any one of claims 1 to 8, wherein the titanium oxide is present on the outermost surface of the surface layer in a state where the titanium oxide can come into contact with moisture in the outside air.

10. The ratio of the tungsten oxide atoms: titanium atoms on the surface of the surface layer is 0.05 to 0.50: 0.99 in terms of a value measured by X-ray photoelectron spectroscopy. The member according to any one of claims 1 to 9, wherein the number is 5 to 0.50.

11. The member according to any one of claims 1 to 10, wherein the proportion of the tungsten oxide in the surface layer is 0.1% to 70% by weight.

12. The member according to any one of claims 1 to 10, wherein the proportion of the tungsten oxide in the surface layer is 5% to 50% by weight.

13. The member according to any one of claims 1 to 11, wherein the tungsten oxide has oxygen vacancies.

14. The surface layer according to any one of claims 1 to 13, wherein the surface layer further comprises a metal oxide having at least one bond selected from the group consisting of a siloxane bond, a porosiloxane bond, and an aluminosilicate bond. A member according to claim 1.

15. The surface of the surface layer further comprises a metal oxide layer having at least one kind of bond selected from the group consisting of a siloxane bond, a porosiloxane bond, and an aluminosilicate bond. 14. The member according to any one of 1 to 13.

16. The member according to claim 15, wherein the thickness of the metal oxide is in a range of 1 nm to 100 nm.

17. The member according to any one of claims 1 to 16, wherein the light excitation is performed by irradiation of sunlight or light from indoor lighting.

18. The member according to any one of claims 1 to 17, wherein the surface layer is substantially transparent.

19. 10 / W / cm ² is used under the following ultraviolet illumination, consisting of members according to any one of claims 1 to 18 antifogging member.

20. 10 W / cm ² is used under the following ultraviolet illumination, consisting of members according to any one of claims 1 to 18 Antifouling member.

21. A method for producing a member according to claim 7, wherein

A coating composition obtained by mixing a liquid containing photocatalytic titanium oxide and / or a precursor thereof and a liquid containing amorphous tungsten oxide and Z or a precursor thereof on the surface of a base material. Applying step;

A step of heat-treating the substrate surface coated with the composition at a temperature at which the titanium oxide and the amorphous tungsten oxide do not form a solid solution. At least comprising:

22. A method for producing a member according to claim 8, wherein

Forming a titanium oxide layer containing photocatalytic titanium oxide particles on the substrate surface,

Forming a layer comprising amorphous tungsten oxide and / or a precursor thereof on the surface of the titanium oxide layer;

Heat-treating the surface of the base material at a temperature while the titanium oxide and the amorphous tungsten oxide do not form a solid solution;

At least comprising:

23. The method according to claim 21 or 22, wherein said heat treatment is performed at a temperature of less than 500 ° C.

24. The method according to claim 21 or 22, wherein said heat treatment is performed at a temperature between 20 ° C and 350 ° C.

25. A method for imparting anti-fogging property to a member surface,

Providing a surface layer comprising a photocatalytic titanium oxide and an amorphous tungsten oxide on the substrate, wherein the titanium oxide and the amorphous tungsten oxide are bonded to each other without forming a solid solution. Become

Process the obtained substrate, in terms of UV irradiance perform light irradiation of less than 1 0〃W / cm ^z, photoexcitation

At least comprising the method.

26. A method for imparting antifouling properties to a member surface,

Irradiating the obtained base material with light of not more than 10 cmW / cm ² in terms of ultraviolet illuminance, thereby performing light excitation;

Contacting the substrate with running water to wash away dirt attached to the surface of the substrate.