JP5097682B2 - Photocatalyst film and article having the same - Google Patents

Description

  The present invention relates to a photocatalytic film and an article having the same. More specifically, it has excellent hydrophilic performance formed by a one-coating method on an organic base material, but exhibits almost no decomposition activity, suppresses an increase in haze value, decreases reflectance, and is transparent. The present invention relates to a photocatalyst film having improved properties and an article having the photocatalyst film on an organic base material.

In general, when a photocatalyst is irradiated with light having energy greater than its band gap, electrons are excited in the conduction band and holes are generated in the valence band. The excited electrons reduce the surface oxygen to generate superoxide anions (· O ²⁻ ), and the holes oxidize the surface hydroxyl groups to generate hydroxyl radicals (· OH). It is known that the reactive active oxygen species exhibit a strong oxidative decomposition function and decompose organic substances adhering to the surface of the photocatalyst film with high efficiency.

  By applying such photocatalytic functions, for example, deodorization, antifouling, antibacterial, sterilization, and decomposition / removal of various substances that cause environmental pollution in wastewater and waste gas are being studied. Yes.

  Further, as another function of the photocatalyst, when the photocatalyst is photoexcited, for example, as disclosed in Patent Document 1, the surface of the photocatalyst film exhibits superhydrophilicity with a contact angle of 10 degrees or less with water. It is also known to do. Applying such a superhydrophilic function of photocatalysts, for example, for the purpose of imparting antifogging properties, dripproofing properties, antifouling properties, frostproofing properties, and snow sliding properties, highway soundproof walls, road reflectors, various types For reflectors, street lights, automobile body coats, side mirrors or window films, building materials including window glass, road signs, roadside signs, freezer / refrigerated showcases, various lenses and sensors, etc. The use of a photocatalytic film has been studied.

  Many photocatalysts have been known so far, and titanium oxide is one of the typical examples. In addition to amorphous amorphous type, there are three typical crystal systems of anatase type, rutile type, and brookite type. Titanium oxide exhibits photocatalytic activity in these three crystal systems. It is famous for expressing hydrophilicity. In particular, it is generally known that the anatase type exhibits the highest activity.

  The anatase-type titanium oxide is usually a hydrolysis condensate obtained by a sol-gel method using an organic titanium compound such as titanium alkoxide as a starting material, or a hydrated oxide of an inorganic titanium compound salt such as titanium tetrachloride or titanyl sulfate. It can be obtained by heat treatment from the obtained amorphous titanium oxide. However, since these usually require heat treatment at a high temperature of 400 ° C. or higher, it is inevitable that the cost is high, and it is difficult to form a film on a substrate having poor heat resistance. It is accompanied.

  Therefore, various methods for obtaining a highly active anatase-type titanium oxide at a relatively low temperature have been tried and disclosed.

  For example, when a titanium oxide film is formed on a substrate by a physical film-forming method such as sputtering or vacuum deposition, by introducing a lot of hydroxyl groups into amorphous titanium oxide by introducing water vapor, atoms in the titanium oxide skeleton There has been proposed a method of increasing the mobility of the metal and facilitating the subsequent crystallization by heat treatment (see, for example, Patent Document 2). According to this, it is possible to lower the crystallization temperature to about 200 ° C.

  Further, from a solution containing silicon alkoxide and a hydrolyzable titanium compound, a gel film containing a composite metal oxide or hydroxide in which a titanium compound and silicon alkoxide are blended at a predetermined molar ratio is formed, A method for precipitating titania microcrystals belonging to anatase having a crystal diameter of about several tens to 100 nm by contacting with hot water of 100 ° C. or lower is disclosed (for example, see Patent Document 3).

  Certainly, according to the above-described method, it is considered that an amorphous titanium oxide can be directly formed on a material having low heat resistance such as a plastic substrate, and then an anatase-type titanium oxide can be formed through a low-temperature heat treatment step. . However, the anatase-type titanium oxide obtained by these methods, as clearly shown in that publication, exhibits high organic matter decomposition activity in addition to the expression of photoexcited superhydrophilicity as well as general anatase-type titanium oxide, When directly formed on a plastic substrate, the substrate is eroded in a short period of time due to its high organic matter decomposition activity, and the physical properties of the substrate deteriorate or the photocatalytic function deteriorates due to the removal of the photocatalyst film. Etc. are easily guessed. For this reason, each of the above methods requires a separate active blocking layer together with the anatase-type titanium oxide film, and can be cured at room temperature, for example, made by dispersing anatase-type titanium oxide fine particles in an inorganic binder. Compared with the method of applying the photocatalyst coating agent, no clear superiority was found.

  On the other hand, as a method for directly applying anatase-type titanium oxide onto an organic substrate such as plastic, for example, the surface energy of anatase-type titanium oxide fine particles is reduced by modifying the anatase-type titanium oxide surface with a fluorine-based silane coupling agent. A self-gradient photocatalytic coating agent that floats (segregates) on the surface of the coating film by weakening the interaction with the binder component is known (see Patent Document 4). In addition, a photocatalyst material having a mask melon shape has been proposed by coating the surface of titanium oxide with an inert inorganic material as a photocatalyst and providing numerous pores (see Patent Document 5).

  Since these can avoid that anatase type titanium oxide contacts a organic base material directly, it is thought that it can apply | coat to an organic base material directly. However, all of these require complex surface treatment to prevent the influence of the high oxidizing power of anatase-type titanium oxide on the substrate, and moreover, they are thick due to surface segregation of titanium oxide. There are many restrictions, such as the necessity of micron order and the fact that titanium oxide particles themselves can only be produced with a diameter of several microns.

  By the way, as an alternative to transparent glass, the use of lightweight transparent plastic as an exterior material is progressing. However, unlike glass materials, which are highly hydrophilic (contact angle with water ≈ 20 degrees) and obtain a certain self-cleaning effect, transparent plastic materials are often hydrophobic (contact angle with water> 40 degrees), and over time. Dirt is a big problem.

  There is a method of providing a photocatalyst layer on the base material as a method for providing an organic base material typified by a plastic base material with high hydrophilic performance and exhibiting antifouling properties. Therefore, a layer for protecting the organic base material has to be provided from the oxidative degradability of the reactive active species to be produced. Therefore, a two-layer coating method is required, which is a factor of high cost.

  The inventors of the present invention have made extensive studies in order to deal with such problems. First, the present invention exhibits excellent hydrophilic performance with a one-coat method on an organic base material, but suppresses deterioration of the base material. A technology for forming a photocatalytic film that can be used was found and a patent application was filed (Japanese Patent Application No. 2008-024479).

However, since the surface of the photocatalyst film generally has a higher refractive index than that of the plastic material, the reflectivity is increased before and after the formation of the photocatalyst film, causing glare.
Photocatalyst films used for window materials, automobile side mirrors, curve mirrors, reflectors, and the like that require high hydrophilicity are required to have high transparency as well as particularly high hydrophilic performance.

International Patent Publication No. 96/29375 Pamphlet JP 2000-345320 A JP 2002-97013 A JP 2005-131640 A Japanese Patent No. 3484470

  Under such circumstances, the present invention has excellent hydrophilic performance formed by a one-coating method on an organic base material, which is suitable for fields requiring high hydrophilic performance and transparency. An object of the present invention is to provide a photocatalyst film that exhibits little decomposition activity, suppresses an increase in haze value, lowers reflectance, and improves transparency, and an article having the photocatalyst film on an organic base material. And

As a result of intensive studies to achieve the above object, the present inventors have obtained the following knowledge.
On the organic base material, a specific coating agent is applied by a one-coat method to form an amorphous titanium oxide film having a component gradient structure, and the surface of the amorphous titanium oxide film is subjected to specific conditions. By photocatalyzing or by photocatalytic treatment, a supercatalytic property is exhibited, but a photocatalytic film capable of effectively suppressing deterioration of the organic base material can be obtained while exhibiting almost no decomposition activity on organic substances. I found out.

Further, the refractive index of the surface of the photocatalyst film to be formed is brought close to the refractive index of the organic base material to be used, and the value of “the refractive index of the organic base material−the refractive index of the photocatalyst film surface” is controlled within a specific range. Thus, the increase in haze value can be suppressed, the reflectance can be reduced, and the transparency can be improved. For this purpose, one or two metal oxide particles having a specific particle size range and a low refractive index are used. It has been found that seeds may be used at a specific ratio and contained near the surface of the photocatalytic film.
The present invention has been completed based on such findings.

That is, the present invention
[1] Hydrolysis condensate of titanium alkoxide provided by applying a coating agent containing a complex formed by hydrolysis and condensation of titanium alkoxide and an organic polymer compound only once on an organic base material This is a photocatalytic film obtained by exposing the surface of an amorphous titanium oxide film in which the content ratio of the aqueous solution continuously changes from the surface to the depth direction to a temperature of 100 ° C. or lower in the presence of water vapor. And
(1) The difference between the refractive index of the organic base material and the refractive index of the photocatalytic film surface is expressed by the following relational expression (1):
0 ≦ refractive index of organic base material−refractive index of photocatalytic film surface <0.25 (1)
And (2) the photocatalyst film, in addition to the photocatalyst particles, metal oxide particles A having an average particle size of less than 40 nm, metal oxide particles B having an average particle size of 40 nm or more and less than 80 nm, and an average particle size of 80 nm or more The metal oxide particles C of less than 150 nm have a mass ratio of A to B of 100: 0 to 0: 100, or a mass ratio of A to C of 100: 0 to 45:55. Including to be,
A photocatalytic film characterized by
[2] The above item [1], which is a photocatalytic film obtained by heat-treating the surface of an amorphous titanium oxide film coated on an organic base material at a temperature of 100 ° C. or less in the presence of moisture. The photocatalytic film according to
[3] The photocatalyst film according to the above [1] or [2], wherein the metal oxide particles A to C other than the photocatalyst particles are silica fine particles and / or rutile-type titanium oxide fine particles,
[4] The photocatalyst film according to the above [3], wherein the metal oxide particles A to C are silica fine particles,
[5] The photocatalyst film according to any one of the above [1] to [4], wherein the refractive index of the photocatalyst film surface is adjusted by controlling the mixing ratio of the metal oxide particles A to C.
[6] The photocatalyst according to any one of [1] to [5] above, wherein an increase in haze value before and after the formation of the photocatalyst film is 0.2% or less as measured in accordance with JIS K 7361. film,
[7] An article having the photocatalyst film described in any one of [1] to [6] above on the surface of an organic base material, and [8] Further functioning on the surface of the photocatalyst film The article according to the above [7], having a film,
Is to provide.

  According to the present invention, it has an excellent hydrophilic performance formed by a one-coating method on an organic base material, but exhibits almost no decomposition activity, and suppresses an increase in the haze value of the organic base material, It is possible to provide a photocatalytic film in which the reflectance is reduced and the transparency is improved, and an article having the photocatalytic film on an organic base material.

First, the photocatalytic film of the present invention will be described.
The photocatalyst film of the present invention is a titanium alkoxide provided by applying a coating agent containing a complex formed by hydrolysis and condensation of a titanium alkoxide and an organic polymer compound only once on an organic base material. It was obtained by exposing the surface of the amorphous titanium oxide film in which the content of the hydrolysis condensate continuously changes from the surface to the depth direction at a temperature of 100 ° C. or less in the presence of water vapor. It is a photocatalytic film.

[Properties of photocatalyst film]
The photocatalytic film of the present invention is an amorphous titanium oxide having a component gradient structure in which the content of the titanium alkoxide hydrolysis condensate provided on the organic base material continuously changes from the surface in the depth direction. The film surface is exposed to a temperature of 100 ° C. or lower in the presence of water vapor and photocatalyzed, or is heat-treated at a temperature of 100 ° C. or lower in the presence of moisture to obtain a photocatalyst. It has a characteristic that it exhibits super hydrophilicity but exhibits almost no decomposition activity on organic substances.
The photocatalyst film of the present invention thus obtained preferably contains photo semiconductor particles, and the photo semiconductor particles preferably contain crystalline titanium oxide.

  The crystalline titanium oxide may be any of anatase type, rutile type, brookite type crystalline titanium oxide, or the above crystalline titanium oxide containing crystal defects and crystal distortion, A combination of two or more of these crystalline titanium oxides may be used.

  Further, the ratio of the crystalline titanium oxide having a crystal diameter in the range of 1 to 10 nm in the total crystalline titanium oxide contained in the photocatalytic film of the present invention is preferably 90% or more, and 100%. It is more preferable.

  In the present invention, the crystal diameter means the maximum length of lattice fringes of crystal grains when a cross section of crystalline titanium oxide is observed with a transmission electron microscope, and the crystal diameter is in the range of 1 to 10 nm. The content ratio of a certain crystalline titanium oxide can be obtained by calculating the ratio of the number of crystals having a crystal diameter in the range of 1 to 10 nm with respect to the total number of crystals when the cross section of the photocatalyst film is observed with a transmission electron microscope. .

  The photocatalyst film of the present invention preferably has at least 5 crystal grains, preferably 10 or more, by observing a cross section of the photocatalyst film in a 50 nm × 50 nm range with a transmission electron microscope. Is more preferable. When the number of crystal grains in the observation range is 5 or more, it is possible to obtain a photocatalyst film having a superhydrophilicity imparting function but having suppressed decomposition activity. The photocatalyst film of the present invention is preferably formed by dispersing crystalline titanium oxide in amorphous titanium oxide. In this case, for example, it is preferable that the crystallized titanium particles are scattered in islands in the amorphous titanium oxide sea when observed with a transmission electron microscope.

  The photocatalyst film of the present invention preferably has a limit contact angle with water of less than 20 degrees at the time of sunlight irradiation, more preferably 10 degrees or less.

In the photocatalyst film of the present invention, the degradation rate of methylene blue when irradiated with artificial sunlight of 3 mW / cm ² is 0.1 or less in terms of the rate of decrease in absorbance (decomposition activity) ΔABS / min at the maximum absorption wavelength of the applied methylene blue. Is preferably 0.05 or less, more preferably 0.01 or less, and even more preferably 0.0015 or less.

  The contact angle with water and the decomposition rate of methylene blue can be controlled, for example, by adjusting the crystal diameter and content ratio of crystalline titanium oxide.

Furthermore, the photocatalytic film of the present invention is
(1) The difference between the refractive index of the organic base material and the refractive index of the photocatalytic film surface is expressed by the following relational expression (1):
0 ≦ refractive index of organic base material−refractive index of photocatalytic film surface <0.25 (1)
And (2) the photocatalyst film, in addition to the photocatalyst particles, metal oxide particles A having an average particle size of less than 40 nm, metal oxide particles B having an average particle size of 40 nm or more and less than 80 nm, and an average particle size of 80 nm or more The metal oxide particles C of less than 150 nm have a mass ratio of A to B of 100: 0 to 0: 100, or a mass ratio of A to C of 100: 0 to 45:55. Including to be,
Cost.

  As the organic base material on which the photocatalytic film of the present invention is formed, a base material made of a highly transparent plastic such as polycarbonate, polyethylene terephthalate, polymethyl methacrylate, or the like is preferably used. The refractive index of the polycarbonate or polyethylene terephthalate base material is about 1.6, and the refractive index of the polymethylmethacrylate base material is about 1.5. Each base material exhibits reflection characteristics corresponding to the refractive index. When the photocatalyst films having different refractive indexes are laminated on such a substrate, the reflection characteristics of the surface are determined by the refractive index of the photocatalyst film. Further, depending on the thickness of the photocatalyst film, interference may occur between the reflected light on the surface of the photocatalyst film and the reflected light from the interface with the base material, resulting in coloration.

  Therefore, in order to make the photocatalyst film of the present invention transparent, it is the simplest and most effective to make the refractive index of the substrate coincide with the refractive index of the photocatalyst film formed thereon as much as possible.

  The photocatalytic film of the present invention has a component gradient structure as described above, and the organic base material side is substantially an organic polymer compound component, and the opposite side (open side) is a titanium alkoxide hydrolysis condensate. And other inorganic components including metal oxide particles. Therefore, the refractive index at the organic base material side interface of the photocatalyst film is about 1.5, but the refractive index at the surface side (open surface side) is the refractive index of the metal oxide particles in the inorganic component. By appropriately selecting the diameter and the content rate, it is possible to approach the refractive index of the organic base material used.

  In the present invention, by using silica fine particles having a low refractive index, preferably colloidal silica, as the metal oxide particles, the refractive index of the surface of the photocatalyst film can be easily brought close to the refractive index of the organic base material used. Can do.

  In the present invention, “refractive index of organic base material−refractive index of photocatalyst film surface” is controlled to 0 or more and less than 0.25. When the refractive index is less than 0 (the refractive index of the photocatalytic film surface is larger than the refractive index of the organic base material), the transparency is lowered. On the other hand, when the refractive index is 0.25 or more, interference fringes are likely to occur. A preferable value of the refractive index difference is in the range of 0 to 0.20.

  On the other hand, it is also possible to reduce the reflectance by providing nano-level roughness on the surface of the photocatalyst film. Therefore, in the present invention, in addition to the photocatalyst particles, the metal oxide particles A having an average particle size of less than 40 nm, the metal oxide particles B having an average particle size of 40 nm or more and less than 80 nm, and the average particle size of 80 nm or more and 150 nm are included in the photocatalyst film. The metal oxide particles C having a mass ratio of A to B of 100: 0 to 0: 100 or a mass ratio of A to C of 100: 0 to 45:55 It is made to contain. From the relationship of the refractive index on the surface of the photocatalyst film, the metal oxide particles are preferably silica fine particles, preferably colloidal silica.

  By satisfying such conditions, the reflectance is reduced and the transmittance is improved while suppressing the increase in haze value before and after the formation of the photocatalyst film to 0.2% or less, which is measured according to JIS K 7361. be able to.

  When the mixing ratio of the metal oxide particles having the average particle diameter deviates from the above range, the haze value before and after the formation of the photocatalyst film may increase by more than 0.2%. Moreover, when a particle having an average particle diameter of 150 nm or more is used as the metal oxide particle, the haze value is significantly increased.

When the refractive index of the photocatalyst film surface needs to be higher, the refractive index can be increased to about 1.9 by using inert rutile titanium oxide fine particles as metal oxide particles. It becomes possible.
The refractive index of the organic base material and the refractive index of the photocatalyst film surface are values measured according to the following method.

<Measurement of refractive index>
(1) Refractive index of an organic base material About the organic base material which is going to measure a refractive index, reflection of 400 nm-800 nm using the ultraviolet-visible-infrared spectrophotometric system "V-600" by JASCO Corporation. The rate spectrum R and the transmittance spectrum T are measured, and then a black matte paint is applied to the back surface of the substrate, and then the surface reflectance spectrum Ro is measured in the same manner.
Next, the extinction coefficient km is obtained from the reflectance R, Ro, transmittance T and base material thickness d (unit: nm) at the wavelength λ using the following formula to obtain the refractive index nm.

最後にそれぞれの波長で得られたｎｍの平均値を持って、基材の屈折率とする。

Finally, the average value of nm obtained at each wavelength is used as the refractive index of the substrate.

(2) Refractive index of the photocatalyst film surface First, a black matte paint is applied to the non-coated surface of the organic base material coated with the photocatalyst film, and then an ultraviolet / visible / infrared spectrophotometer manufactured by JASCO Corporation. Using “V-600”, a reflectance spectrum Rt of 400 nm to 800 nm on the photocatalyst coating surface side is measured. Further, the cross section of the thin film is observed using an electron microscope “JSM-6700F” manufactured by JEOL Ltd., and the film thickness d is measured. (Confirm that it is the same as the set thickness.)
On the other hand, based on the extinction coefficient km, refractive index nm, thin film thickness d of the organic base material known in (1) above, and the approximate extinction coefficient kp, refractive index np of the photocatalytic thin film, The reflectance spectrum Rs of 400 nm to 800 nm on the photocatalyst coating surface side is calculated using the following formula.

  While comparing the actual reflectance spectrum Rt and the measured reflectance Rs, adjusting the approximate extinction coefficient kp and refractive index np of the photocatalyst used in the calculation, the two spectra are matched, and the spectra match. The refractive index np was the true refractive index of the photocatalytic film. In Examples 5 to 8 and Comparative Examples 4 to 6 described later, since the surface has an uneven structure, the refractive index cannot be calculated by this method. The refractive indexes of these coating films were approximated to be the same as the refractive indexes of the photocatalytic films of Example 3 and Example 4 in which the average particle diameter of silica particles was different and the mass ratio was the same.

  The haze value of the organic base material and the haze value of the organic base material provided with the photocatalyst film are values measured according to the following method.

<Measurement of haze value>
(1) Haze value of organic base material About a predetermined organic base material, haze value is calculated | required based on JISK7361 using Nippon Denshoku Co., Ltd. haze meter "NDH-2000".
(2) Haze value of organic base material provided with photocatalyst film Haze meter "NDH-2000" manufactured by Nippon Denshoku Co., Ltd. is used for a photocatalyst film having a thickness of 100 nm on a predetermined organic base material. The haze value is obtained in accordance with JIS K 7361.

The total amount of metal oxide particles A and B contained in the photocatalyst film of the present invention or the total amount of A and C takes into account the difference in the refractive index of the photocatalyst film surface and the haze value before and after the photocatalyst film formation. 10 to 85% by mass, more preferably 20 to 80% by mass.
In addition, the average particle diameter of each said metal oxide particle is a value measured by a laser scattering diffraction method.

[Production of photocatalytic film]
As described above, the photocatalyst film of the present invention contains crystalline titanium oxide which is a photo semiconductor particle, and has a specific particle size range in addition to the photocatalyst particle, in order to give unevenness to the surface. Product particles A and B, or metal oxide particles A and C. Further, titanium alkoxide is hydrolyzed and condensed with the organic polymer compound to form a complex whose content continuously changes from the surface in the depth direction.

  Specific examples of the titanium alkoxide include titanium tetraalkoxide described below, and specific examples of the organic compound include an organic polymer compound having a hydrolyzable metal-containing group described below.

  The photocatalytic film of the present invention preferably further comprises at least one metal compound selected from inorganic metal salts, organic metal salts, and alkoxides of metals other than titanium and silicon. Specific examples of the metal compound are as described later, and aluminum nitrate is particularly preferable.

  The photocatalytic film of the present invention is obtained by subjecting an amorphous titanium oxide film to a temperature of 100 ° C. or lower in the presence of water vapor or by heat treatment at a temperature of 100 ° C. or lower in the presence of moisture. Manufactured. In this case, it is preferable to produce the photocatalyst in an environment having a temperature of 100 ° C. or lower and a relative humidity of 5% or higher.

Further, in the present invention, in the above environment, it is preferable to produce in the presence of light including ultraviolet light while further having a wavelength in an arbitrary region selected from a wavelength region of 250 to 1200 nm. One suitable manufacturing condition is that the temperature is 30 to 60 ° C. and the relative humidity is 50 to 80% while irradiating under an illuminance of 5 to 400 W / m ² .

The light having an arbitrary region selected from the wavelength region of 250 to 1200 nm and including the ultraviolet light preferably includes at least light having a wavelength of 250 to 260 nm, 290 to 315 nm, and 350 to 1200 nm. It is further preferable to irradiate under the condition of irradiance of 200 to 400 W / m ² .

  In the present invention, it is preferable to spray water at least once. There are no particular restrictions on the equipment and equipment used in the present invention, but typically, various equipment that can provide a constant temperature and humidity environment, carbon arc type sunshine weather meter, xenon weather meter, metering weather meter, dew panel A weather meter can be exemplified.

  In addition, the photocatalyst film of the present invention can be similarly produced by exposure in an outdoor environment in which the same conditions as described above are obtained.

  The photocatalyst film of the present invention comprises (A) a titania sol obtained by hydrolytic condensation of titanium alkoxide, and (B) a metal-containing group that can be bonded to titanium oxide by hydrolysis in the molecule (referred to as a hydrolyzable metal-containing group). And (C) a coating agent containing metal oxide particles for forming irregularities, and this film is produced by photocatalysis under the production conditions described above. The

  In the preparation of titania sol obtained by hydrolytic condensation of titanium tetraalkoxide as component (A), titanium tetraalkoxide having about 1 to 4 carbon atoms of the alkoxyl group is used as the raw material titanium tetraalkoxide. In this titanium tetraalkoxide, the four alkoxyl groups may be the same or different, but the same one is preferably used from the viewpoint of availability. Examples of the titanium tetraalkoxide include titanium tetramethoxide, titanium tetraethoxide, titanium tetra-n-propoxide, titanium tetraisopropoxide, titanium tetra-n-butoxide, titanium tetraisobutoxide, titanium tetra-sec-butoxide and An example is titanium tetra-tert-butoxide. These may be used individually by 1 type and may be used in combination of 2 or more type.

  The titanium tetraalkoxide is hydrolyzed and condensed to prepare a titania sol solution. This hydrolysis-condensation reaction of the titanium tetraalkoxide is preferably carried out by using water having an alcohol having an ether-based oxygen having 3 or more carbon atoms as a solvent and allowing water to act on the titanium tetraalkoxide.

  Examples of the alcohols having ether oxygen having 3 or more carbon atoms include solvents having an interaction with titanium tetraalkoxide, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether. Cellosolve solvents such as ethylene glycol mono-t-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol Monobutyl ether, etc. It can be mentioned. Among these, a cellosolve solvent having a strong interaction with titanium tetraalkoxide is particularly preferable. These solvents may be used singly or in combination of two or more.

  By using a solvent having such an interaction with titanium tetraalkoxide as a solvent, the titania sol solution obtained by the hydrolysis-condensation reaction of titanium tetraalkoxide can be stabilized, and the condensation reaction can proceed. However, gelation and particle formation are less likely to occur.

  The hydrolysis-condensation reaction of titanium tetraalkoxide is about 4 to 20 times mol, preferably 5 to 12 times mol of the above alcohols and about 0.5 times mol to less than 4 times mol of titanium tetraalkoxide, preferably Is carried out at a temperature in the range of usually 0 to 70 ° C., preferably 20 to 50 ° C. in the presence of an acidic catalyst such as hydrochloric acid, sulfuric acid or nitric acid, using 1 to 3.0 moles of water. An acidic catalyst is 0.1-1.0 times mole normally with respect to titanium tetraalkoxide, Preferably it is used in 0.2-0.7 times mole.

  The organic polymer compound having a hydrolyzable metal-containing group as the component (B) includes, for example, (x) an ethylenically unsaturated monomer having a hydrolyzable metal-containing group, and (y) an ethylenic compound not containing a metal. It can be obtained by copolymerizing unsaturated monomers.

  Examples of the ethylenically unsaturated monomer having a hydrolyzable metal-containing group as the component (B) (x) include those represented by the general formula (2)

Wherein R ¹ is a hydrogen atom or a methyl group, A is an alkylene group, preferably an alkylene group having 1 to 4 carbon atoms, and R ² is a hydrolyzable group or a non-hydrolyzable group, the first is hydrolysis, it is required to be a hydrolyzable group capable of binding the component (a) and the chemical, and when R ² is plural, each R ² is also a mutually identical M ¹ is a metal atom such as silicon, titanium, zirconium, indium, tin, and aluminum, and k is the valence of the metal atom M ¹ .
Can be mentioned.

In the above general formula (2), examples of the hydrolyzable group that can chemically bond with the component (A) by hydrolysis of R ² include halogen atoms such as alkoxyl groups, isocyanate groups, and chlorine atoms, oxyhalogen groups, An acetylacetonate group, a hydroxyl group, etc. are mentioned, On the other hand, as a non-hydrolyzable group which does not chemically bond with (A) component, a lower alkyl group etc. are mentioned preferably, for example.

Examples of the metal-containing group represented by -M ¹ R ² _k-1 in the general formula (2) include a trimethoxysilyl group, a triethoxysilyl group, a tri-n-propoxysilyl group, a triisopropoxysilyl group, Tri-n-butoxysilyl group, triisobutoxysilyl group, tri-sec-butoxysilyl group, tri-tert-butoxysilyl group, trichlorosilyl group, dimethylmethoxysilyl group, methyldimethoxysilyl group, dimethylchlorosilyl group, methyl Dichlorosilyl group, triisocyanatosilyl group, methyldiisocyanatosilyl group, trimethoxytitanium group, triethoxytitanium group, tri-n-propoxytitanium group, triisopropoxytitanium group, tri-n-butoxytitanium group, Triisobutoxy titanium group, tri-s ec-butoxytitanium group, tri-tert-butoxytitanium group, trichlorotitanium group, trimethoxyzirconium group, triethoxyzirconium group, tri-n-propoxyzirconium group, triisopropoxyzirconium group, tri-n-butoxy Zirconium group, triisobutoxyzirconium group, tri-sec-butoxyzirconium group, tri-tert-butoxyzirconium group, trichlorozirconium group, or even dimethoxyaluminum group, diethoxyaluminum group, di-n-propoxyaluminum group, Diisopropoxyaluminum group, di-n-butoxyaluminum group, diisobutoxyaluminum group, di-sec-butoxyaluminum group, di-tert-butoxyaluminum group, Such as chloro aluminum group.

  One type of the ethylenically unsaturated monomer of component (x) may be used, or two or more types may be used in combination.

  On the other hand, examples of the ethylenically unsaturated monomer that does not contain a metal as the component (y) include, for example, the general formula (3)

（式中、Ｒ^３は水素原子またはメチル基、Ｘは一価の有機基である。）
で表されるエチレン性不飽和単量体、好ましくは一般式（３−ａ）

(In the formula, R ³ is a hydrogen atom or a methyl group, and X is a monovalent organic group.)
An ethylenically unsaturated monomer represented by the formula (3-a), preferably

(In the formula, R ³ is the same as described above, and R ⁴ represents a hydrocarbon group.)
Or an ethylenically unsaturated monomer represented by the above general formula (3-a), and a general formula ( 3-b)

(In the formula, R ⁵ represents a hydrogen atom or a methyl group, and R ⁶ represents an epoxy group, a halogen atom or a hydrocarbon group having an ether bond.)
And a mixture with an ethylenically unsaturated monomer represented by the formula:

In the ethylenically unsaturated monomer represented by the general formula (3-a), as the hydrocarbon group represented by R ⁴ , a linear or branched alkyl group having 1 to 10 carbon atoms, carbon number Preferable examples include 3 to 10 cycloalkyl groups, aryl groups having 6 to 10 carbon atoms, and aralkyl groups having 7 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and various butyl groups, pentyl groups, hexyl groups, octyl groups, and decyl groups. Examples of the cycloalkyl group having 3 to 10 carbon atoms include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, and a cyclooctyl group. Examples of the aryl group having 6 to 10 carbon atoms include a phenyl group, a tolyl group, and a xylyl group. Examples of the aralkyl group having 7 to 10 carbon atoms, such as a group, a naphthyl group, and a methylnaphthyl group, include a benzyl group, a methylbenzyl group, a phenethylyl group, and a naphthylmethyl group.

  Examples of the ethylenically unsaturated monomer represented by the general formula (3-a) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl ( Examples include meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, phenyl (meth) acrylate, and benzyl (meth) acrylate. These may be used alone or in combination of two or more.

In the ethylenically unsaturated monomer represented by the general formula (3-b), the hydrocarbon group having an epoxy group, a halogen atom or an ether bond represented by R ⁶ is a straight chain having 1 to 10 carbon atoms. Preferred examples include a straight or branched alkyl group, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms. The halogen atom for the substituent is preferably a chlorine atom or a bromine atom. Specific examples of the hydrocarbon group include the same groups as those exemplified in the description of R ⁴ in the general formula (3-a).

  Examples of the ethylenically unsaturated monomer represented by the general formula (3-b) include glycidyl (meth) acrylate, 3-glycidoxypropyl (meth) acrylate, and 2- (3,4-epoxycyclohexyl). ) Ethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-bromoethyl (meth) acrylate and the like can be preferably exemplified.

  In addition to these, the ethylenically unsaturated monomer represented by the general formula (3) includes styrene, α-methylstyrene, α-acetoxystyrene, m-, o- or p-bromostyrene, m -, O- or p-chlorostyrene, m-, o- or p-vinylphenol, 1- or 2-vinylnaphthalene and the like, and stabilizers for polymerizable polymers having an ethylenically unsaturated group, for example, ethylenic Antioxidants, ultraviolet absorbers and light stabilizers having an unsaturated group can also be used. These may be used alone or in combination of two or more.

  Further, when the ethylenically unsaturated monomer represented by the general formula (3-a) and the ethylenically unsaturated monomer represented by the general formula (3-b) are used in combination, the former ethylenic monomer It is preferable to use the latter ethylenically unsaturated monomer in a proportion of 1 to 100 mol% with respect to the unsaturated monomer.

  In the presence of a radical polymerization initiator, an ethylenically unsaturated monomer having a hydrolyzable metal-containing group as the component (x) and an ethylenically unsaturated monomer not containing a metal as the component (y) By copolymerization, an organic polymer compound having a hydrolyzable metal-containing group as component (B) is obtained.

  On the other hand, as described above, the metal oxide particles for forming irregularities as the component (C) are the metal oxide particles A having an average particle size of less than 40 nm and the metal oxide particles B having an average particle size of 40 nm or more and less than 80 nm. In a mass ratio of 100: 0 to 0: 100, or the metal oxide particles A and the metal oxide particles C having an average particle size of 80 nm or more and less than 150 nm in a mass ratio of 100: 0 to 45:55. Used at a ratio of

  As the metal oxide particles A to C, at least one selected from silica fine particles and rutile-type titanium oxide fine particles is used. In the present invention, from the viewpoint of reducing the refractive index of the photocatalyst film surface, silica is used. Fine particles are preferable, and colloidal silica is particularly preferable.

  In the present invention, the titania sol solution (A) obtained as described above and the organic polymer compound having a hydrolyzable metal-containing group (B) component are dissolved in an appropriate polar solvent. A coating solution can be obtained by adjusting the mixed solution of the solution thus prepared and the metal oxide particles for forming irregularities as the component (C) to a viscosity suitable for coating. At this time, if necessary, water and / or an acidic catalyst may be added to the coating solution.

  By including the component (C) in the coating liquid, irregularities are imparted to the surface of the resulting photocatalyst film, the reflectance is lowered, and the transparency is improved.

  Furthermore, the coating agent used for forming an amorphous titanium oxide film having a component gradient structure includes an inorganic metal salt, an organic metal salt, and a metal other than titanium and silicon as a substance that regulates crystal formation of amorphous titanium oxide. At least one metal-based compound selected from the alkoxides can be contained. Specifically, aluminum nitrate, aluminum acetate, aluminum sulfate, aluminum chloride, various salts such as zirconium nitrate, zirconium acetate, zirconium sulfate, zirconium chloride, and hydrates of these inorganic salts, aluminum triacetylacetonate, etc. And metal alkoxides such as tetra-n-propoxyzirconium, tetraethoxysilane, and phenyltrimethoxysilane, and hydrolysates or condensates of these compounds. Of these, aluminum nitrate and hydrates thereof are particularly preferred. The said crystal formation regulator may be used individually by 1 type, and may be used in combination of 2 or more type.

  As described above, by including the crystal formation adjusting substance in the coating agent, it is possible to adjust the microcrystal formation behavior (for example, crystal formation rate, crystal growth rate, etc.) of titanium oxide in the formed photocatalytic film. . In addition, it is possible to control the time until the onset of super hydrophilicity according to the environment used and the required performance, and to contribute to the adjustment of the stability of the film, such as suppressing the occurrence of cracks due to shrinkage. You can also.

  In the present invention, the coating liquid obtained as described above on the organic base material has a dry coating thickness of usually 0.01 to 1 μm, preferably 0.03 to 0.3 μm. The coating is performed by a known means such as a dip coating method, a spin coating method, a spray coating method, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, and a solvent. It is preferable to volatilize and form a coating film.

  Examples of the organic base material include acrylic resins such as polymethyl methacrylate, styrene resins such as polystyrene and ABS resins, olefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, 6- Substrates made of polyamide resins such as nylon and 6,6-nylon, polyvinyl chloride resins, polycarbonate resins, polyphenylene sulfide resins, polyphenylene ether resins, polyimide resins, cellulose resins such as cellulose acetate, etc. Can be mentioned.

  These organic base materials can be subjected to surface treatment by an oxidation method, an unevenness method, or the like, if desired, in order to further improve the adhesion to the component gradient film according to the present invention. Examples of the oxidation method include corona discharge treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment and the like, and examples of the unevenness method include sand blast method and solvent treatment method. Is mentioned. These surface treatment methods are appropriately selected according to the type of substrate.

  In the present invention, the coating film formed in this way is usually subjected to a heat treatment at a temperature of 0 to 200 ° C., preferably 15 to 150 ° C., thereby forming a component gradient structure with irregularities on the surface. An amorphous titanium oxide film is formed.

The component gradient structure is confirmed, for example, by performing sputtering on the obtained film surface and measuring the content of carbon atoms and titanium atoms on the film surface over time by X-ray photoelectron spectroscopy or the like. be able to.
Next, the article of the present invention will be described.

[Goods]
The article of the present invention has the photocatalyst film of the present invention on the surface of an organic base material.
Furthermore, the article of the present invention can further be provided with a functional film having a thickness of 500 nm or less on the surface of the photocatalyst film as long as the function of the photocatalyst film of the present invention is not impaired.

  Examples of the function of the functional film include hydrophilicity retention in a dark place, conductivity, chargeability, hard coat property, reflection characteristic control, refractive index control, and the like. In addition, specific constituent components of the functional film include metal oxide compounds such as silica, alumina, zirconia, ITO, and zinc oxide. In particular, it is preferable to contain silica for the purpose of maintaining hydrophilicity at night when sunlight is not applied.

  In the article of the present invention, examples of the organic base material on which the photocatalytic film is formed include the same organic base materials as exemplified above, and, similarly to the above, a photocatalytic film provided thereon In order to improve the adhesion, surface treatment can be performed by an oxidation method, an unevenness method, or the like.

  As articles of the present invention, sound barriers for highways, road reflectors, various reflectors, street lamps, body coats and side mirrors for automobiles including automobiles, films for windows, building materials including window glass, road signs, There are roadside signs, freezer / refrigerated showcases, various lenses and sensors.

  Moreover, an agricultural film can also be mentioned as an article of the present invention. In recent years, agricultural films have been actively used for house cultivation and tunnel cultivation, and in such cultivation, when agricultural films are spread and used, they prevent fogging caused by water droplet adhesion. Therefore, after spreading, a drip-proof agent (anti-fogging agent) was sprayed on the inner surface, but this drip-proof agent (anti-fogging agent) lost the drip-proof effect in a short period of time. On the other hand, the agricultural film having the photocatalytic film of the present invention on the surface can maintain hydrophilicity for a long period of time, so that it is possible to continue the farm work without requiring recoating.

  As described above, the article of the present invention has a superhydrophilicity imparting function, but has a photocatalyst film with suppressed decomposition activity, so that the surface of the article can be made hydrophilic without eroding the organic base material. It becomes possible to become.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

In addition, the performance of the photocatalyst film formed in each example was measured according to the following method.
(1) Refractive index of organic base material and refractive index of photocatalyst film surface Measured according to the method described in the specification.
(2) Difference in haze value According to the method described in the specification, the haze value of the organic base material provided with the organic base material and the photocatalyst film was measured, and the difference in haze value before and after the photocatalyst film formation (photocatalyst film formation) Later haze value-haze value before formation) was determined.
(3) Difference in total light transmittance The total light transmittance of the organic base material and the total light transmittance of the organic base material provided with the photocatalyst film were measured using a Nippon Denshoku haze meter “NDH-2000”. It used and measured based on JIS K 7361, The difference of the total light transmittance before and behind photocatalyst film formation (total light transmittance after photocatalyst film formation-total light transmittance before formation) was calculated | required.
(4) Specific surface area The specific surface area of the photocatalyst film surface was measured with an atomic force microscope AFM (manufactured by Keyence Corporation, “VN8000”).
(5) Presence or absence of interference color Photocatalyst coated surface (surface) and non-coated surface of organic base material coated with photocatalyst using UV-VIS / IR spectrophotometric system "V-600" manufactured by JASCO Corporation ( The reflectance spectrum of 400 nm to 800 nm on the back surface is measured.

  In each reflectance spectrum, the maximum and minimum values of reflectance between 400 nm and 800 nm are calculated. If the difference is less than 3%, there is no interference. If the difference is between 3% and less than 5%, there is slight interference. It was assumed that there was interference at 5% or more.

Synthesis Example 1: Preparation of Titanium Alkoxide Hydrolysis Condensate To 149 g of ethyl cellosolve, 75.7 g of titanium tetraisopropoxide (trade name: A-1, manufactured by Nippon Soda Co., Ltd.) was added dropwise with stirring, and the solution ( A) was obtained. To this solution (A), a mixed solution of 58.3 g of ethyl cellosolve, 4.55 g of distilled water and 12.6 g of 60 mass% concentrated nitric acid was added dropwise with stirring to obtain a solution (B). Thereafter, the solution (B) was stirred at 30 ° C. for 4 hours to obtain a hydrolytic condensation liquid (C) of titanium alkoxide.

Synthesis Example 2: Preparation of organic polymer component solution 704 g of methyl isobutyl ketone, 332 g of methyl methacrylate and 42.0 g of methacryloxypropyltrimethoxysilane were added to a 2 L separable flask under a nitrogen atmosphere, and the temperature was raised to 60 ° C. To this mixed solution, 103 g of methyl isobutyl ketone in which 3.2 g of azobisisobutyronitrile was dissolved was dropped to start the polymerization reaction, and stirred for 30 hours to obtain an organic polymer component solution (D).

Example 1
4.37 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 30.6 g of ethyl cellosolve, and then the hydrolytic condensation liquid (C) of titanium alkoxide prepared in Synthesis Example 1 was 39. .4 g was added and stirred well to obtain a solution (G). Subsequently, 5.21 g of the organic polymer component solution (D) prepared in Synthesis Example 2, 233.2 g of methyl isobutyl ketone, 164.0 g of ethyl cellosolve, 74.4 g of the solution (G) described above, and colloidal silica A ( Product name: Snowtex IPA-ST (average particle diameter 20 nm), manufactured by Nissan Chemical Industries, Ltd.) 23.2 g in this order, then stirred in a 33 ° C. bath for 24 hours, colloidal silica and aluminum nitrate A gradient film coating solution (H) of a hydrolyzate of titanium alkoxide and an organic polymer component was prepared. At this time, the colloidal silica in the coating liquid (H) solid content was 50 mass%.

  Thereafter, the coating liquid (H) is applied to a 2 mm-thick colorless transparent acrylic plate (Mitsubishi Rayon, Acrylite L) having a refractive index of 1.49 using a spin coater with a wet thickness of about 10 μm, The dry thickness was applied to 100 nm. Next, this coating film was photocatalyzed in a constant temperature and humidity chamber at 85 ° C. and 95% RH for 15 hours to form a photocatalytic film. The photocatalytic film had a refractive index of 1.49. The difference in the total light transmittance (Tt) and haze value between the obtained samples before and after coating was less than 0.1%. In addition, no interference color was observed.

  In addition, using an XPS apparatus “PHI-5600” [manufactured by ULVAC-PHI Co., Ltd.], argon sputtering (4 kV) was applied at intervals of 3 minutes to scrape the film, and the content of carbon atoms and metal atoms on the film surface was determined by X-ray photoelectron. As a result of measurement by spectroscopic method and investigation of the gradient, it was confirmed that it has a component gradient structure in which the content of metal atoms continuously decreases in the depth direction from the surface.

Example 2
1.75 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 12.3 g of ethyl cellosolve, and then the hydrolytic condensate (C) of titanium alkoxide prepared in Synthesis Example 1 was dissolved. .8 g was added and stirred well to obtain a solution (G). Subsequently, 2.09 g of the organic polymer component solution (D) prepared in Synthesis Example 2, 229.4 g of methyl isobutyl ketone, 201.7 g of ethyl cellosolve, 29.8 g of the solution (G) described above, and colloidal silica A ( Trade name: Snowtex IPA-ST (average particle size 20 nm), manufactured by Nissan Chemical Industries, Ltd.) 37.1 g in order, then stirred in a warm bath at 33 ° C. for 24 hours, colloidal silica and aluminum nitrate A gradient film coating solution (H) of a hydrolyzate of titanium alkoxide and an organic polymer component was prepared. At this time, the colloidal silica in the coating liquid (H) solid content was 80 mass%.

  Thereafter, the coating liquid (H) is applied to a 2 mm-thick colorless transparent acrylic plate (Mitsubishi Rayon, Acrylite L) having a refractive index of 1.49 using a spin coater with a wet thickness of about 10 μm, The dry thickness was applied to 100 nm. Then, the same operation as Example 1 was performed and the photocatalyst film | membrane which has a photocatalyst layer on the inclined film surface was produced. The refractive index of this photocatalyst film was 1.35. The obtained sample had a difference in haze value of less than 0.1% before and after coating, but the total light transmittance (Tt) was improved by 1.5%. In addition, no interference color was observed.

Example 3
Next, 6.12 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 42.9 g of ethyl cellosolve, and then the hydrolytic condensation liquid (C) of titanium alkoxide prepared in Synthesis Example 1 was 55. .2 g was added and stirred well to obtain a solution (G). Subsequently, 7.30 g of the organic polymer component solution (D) prepared in Synthesis Example 2, 235.8 g of methyl isobutyl ketone, 138.9 g of ethyl cellosolve, 104.15 g of the solution (G) described above, and colloidal silica A ( Product name: Snowtex IPA-ST (average particle diameter 20 nm), manufactured by Nissan Chemical Industries, Ltd.) 13.9 g in order, then stirred in a 33 ° C. warm bath for 24 hours, colloidal silica and aluminum nitrate A gradient film coating solution (H) of a hydrolyzate of titanium alkoxide and an organic polymer component was prepared. At this time, the colloidal silica in the solid content of the coating liquid (H) was 30% by mass.

  Thereafter, the coating liquid (H) is applied to a 2 mm-thick colorless and transparent polycarbonate plate having a refractive index of 1.59 (manufactured by Plastics Co., Ltd., ECL-100) with a wet thickness of about 10 μm using a spin coater. The film was applied so that the dry thickness was 100 nm. Then, the same operation as Example 1 was performed and the photocatalyst film | membrane which has a photocatalyst layer on the inclined film surface was produced. The photocatalytic film had a refractive index of 1.59. The obtained sample had a difference in haze value of less than 0.1% before and after coating, but the total light transmittance (Tt) was improved by 0.5%. In addition, no interference color was observed.

Example 4
In the same manner as in Example 3, a gradient film coating liquid (H) was obtained.
Thereafter, the coating liquid (H) is applied to a 100 μm-thick colorless transparent polyester film (Lumirror T60, manufactured by Toray, Inc.) having a refractive index of 1.66 with a wet thickness of about 10 μm using a spin coater, and a dry thickness. Was applied to a thickness of 100 nm. Then, the same operation as Example 1 was performed and the photocatalyst film | membrane which has a photocatalyst layer on the inclined film surface was produced. The photocatalytic film had a refractive index of 1.59. The obtained sample had a specific surface area of 1.0000 as a result of measuring the specific surface area with AFM (manufactured by Keyence Corporation, VN8000). The difference in haze value before and after coating was less than 0.1%, but the total light transmittance (Tt) was improved by 0.5%. In addition, no interference color was observed.

Example 5
Next, 6.12 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 42.9 g of ethyl cellosolve, and then the hydrolytic condensation liquid (C) of titanium alkoxide prepared in Synthesis Example 1 was 55. .2 g was added and stirred well to obtain a solution (G). Subsequently, 7.30 g of the organic polymer component solution (D) prepared in Synthesis Example 2, 235.8 g of methyl isobutyl ketone, 138.9 g of ethyl cellosolve, 104.15 g of the solution (G) described above, and colloidal silica A ( Product name: Snowtex IPA-ST (average particle size 20 nm), manufactured by Nissan Chemical Industries, Ltd. 7.0 g, colloidal silica B (product name: Snowtex IPA-ST-L (average particle size 50 nm), Nissan Chemical (Industry Co., Ltd.) 7.0 g in order, then stirred in a hot bath at 33 ° C. for 24 hours, gradient of titanium alkoxide hydrolyzate mixed with colloidal silica and aluminum nitrate and organic polymer component A film coating solution (H) was prepared. At this time, the colloidal silica in the solid content of the coating liquid (H) was 30% by mass, and colloidal silica B / colloidal silica A = 50/50 (mass ratio).

  Thereafter, the coating liquid (H) is applied to a 100 μm-thick colorless transparent polyester film (Lumirror T60, manufactured by Toray, Inc.) having a refractive index of 1.66 with a wet thickness of about 10 μm using a spin coater, and a dry thickness. Was applied to a thickness of 100 nm. Then, the same operation as Example 1 was performed and the photocatalyst film | membrane which has a photocatalyst layer on the inclined film surface was produced. The photocatalytic film had a refractive index of 1.59. The obtained sample had a specific surface area of 1.0005 as a result of measuring the specific surface area with AFM (VN8000, manufactured by Keyence Corporation). The difference in haze value before and after coating was less than 0.1%, but the total light transmittance (Tt) was improved by 1.0%. In addition, no interference color was observed.

Example 6
Next, 6.12 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 42.9 g of ethyl cellosolve, and then the hydrolytic condensation liquid (C) of titanium alkoxide prepared in Synthesis Example 1 was 55. .2 g was added and stirred well to obtain a solution (G). Subsequently, 7.30 g of the organic polymer component solution (D) prepared in Synthesis Example 2, 235.8 g of methyl isobutyl ketone, 138.9 g of ethyl cellosolve, 104.15 g of the solution (G) described above, and colloidal silica A ( Product name: Snowtex IPA-ST (average particle size 20 nm), Nissan Chemical Industries, Ltd. 2.3 g, colloidal silica B (product name: Snowtex IPA-ST-L (average particle size 50 nm), Nissan Chemical (Industry Co., Ltd.) 11.6 g in order, then stirred in a warm bath at 33 ° C. for 24 hours, and the gradient of titanium alkoxide hydrolyzate mixed with colloidal silica and aluminum nitrate and organic polymer component A film coating solution (H) was prepared. At this time, the colloidal silica in the solid content of the coating liquid (H) was 30% by mass, and colloidal silica B / colloidal silica A = 83/17 (mass ratio).

  Thereafter, the coating liquid (H) is applied to a 100 μm-thick colorless transparent polyester film (Lumirror T60, manufactured by Toray, Inc.) having a refractive index of 1.66 with a wet thickness of about 10 μm using a spin coater, and a dry thickness. Was applied to a thickness of 100 nm. Then, the same operation as Example 1 was performed and the photocatalyst film | membrane which has a photocatalyst layer on the inclined film surface was produced. The photocatalytic film had a refractive index of 1.59. As a result of measuring the specific surface area of the obtained sample with AFM (manufactured by Keyence Corporation, VN8000), it was 1.0006. The difference in haze value before and after coating was less than 0.1%, but the total light transmittance (Tt) was improved by 1.5%. In addition, no interference color was observed.

Example 7
Next, 6.12 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 42.9 g of ethyl cellosolve, and then the hydrolytic condensation liquid (C) of titanium alkoxide prepared in Synthesis Example 1 was 55. .2 g was added and stirred well to obtain a solution (G). Subsequently, 7.30 g of the organic polymer component solution (D) prepared in Synthesis Example 2, 235.8 g of methyl isobutyl ketone, 138.9 g of ethyl cellosolve, 104.15 g of the solution (G) described above, and colloidal silica B ( Product name: Snowtex IPA-ST-L (average particle size 50 nm), manufactured by Nissan Chemical Industries, Ltd.) in the order of 13.9 g, and then stirred for 24 hours in a 33 ° C. warm bath, colloidal silica and A gradient film coating solution (H) of a hydrolyzate of titanium alkoxide mixed with aluminum nitrate and an organic polymer component was prepared. At this time, the colloidal silica in the solid content of the coating liquid (H) was 30% by mass.

  Thereafter, the coating liquid (H) is applied to a 100 μm-thick colorless transparent polyester film (Lumirror T60, manufactured by Toray, Inc.) having a refractive index of 1.66 with a wet thickness of about 10 μm using a spin coater, and a dry thickness. Was applied to a thickness of 100 nm. Then, the same operation as Example 1 was performed and the photocatalyst film | membrane which has a photocatalyst layer on the inclined film surface was produced. The photocatalytic film had a refractive index of 1.59. The obtained sample had a specific surface area of 1.0020 as measured by AFM (manufactured by Keyence Corporation, VN8000). Before and after coating, the haze value increased by 0.2% and the total light transmittance (Tt) increased by 1.5%. No interference color was observed.

Example 8
Next, 6.12 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 42.9 g of ethyl cellosolve, and then the hydrolytic condensation liquid (C) of titanium alkoxide prepared in Synthesis Example 1 was 55. .2 g was added and stirred well to obtain a solution (G). Subsequently, 7.30 g of the organic polymer component solution (D) prepared in Synthesis Example 2, 235.8 g of methyl isobutyl ketone, 138.9 g of ethyl cellosolve, 104.22 g of the solution (G) described above, and colloidal silica A ( Product name: Snowtex IPA-ST (average particle size 20 nm), manufactured by Nissan Chemical Industries, Ltd. 7.0 g, colloidal silica C (product name: Snowtex IPA-ST-ZL (average particle size 100 nm), Nissan Chemical (Industry Co., Ltd.) 7.0 g in order, then stirred in a hot bath at 33 ° C. for 24 hours, gradient of titanium alkoxide hydrolyzate mixed with colloidal silica and aluminum nitrate and organic polymer component A film coating solution (H) was prepared. At this time, the colloidal silica in the solid content of the coating liquid (H) was 30% by mass, and colloidal silica C / colloidal silica A = 50/50 (mass ratio).

  Thereafter, the coating liquid (H) is applied to a 100 μm-thick colorless transparent polyester film (Lumirror T60, manufactured by Toray, Inc.) having a refractive index of 1.66 with a wet thickness of about 10 μm using a spin coater, and a dry thickness. Was applied to a thickness of 100 nm. Then, the same operation as Example 1 was performed and the photocatalyst film | membrane which has a photocatalyst layer on the inclined film surface was produced. The photocatalytic film had a refractive index of 1.59. The obtained sample had a specific surface area of 1.0004 as measured by AFM (VN8000, manufactured by Keyence Corporation). Before and after coating, the haze value increased by 0.1% and the total light transmittance (Tt) increased by 1.5%. No interference color was observed.

Comparative Example 1
In 49.0 g of ethyl cellosolve, 7.00 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved, and then the hydrolytic condensate (C) of titanium alkoxide prepared in Synthesis Example 1 was 63. 0.1 g was added and stirred well to obtain a solution (G). Subsequently, 8.34 g of the organic polymer component solution (D) prepared in Synthesis Example 2, 237.0 g of methyl isobutyl ketone, 126.3 g of ethyl cellosolve, 119.0 g of the solution (G) described above, and colloidal silica A ( Product name: Snowtex IPA-ST (average particle diameter 20 nm), manufactured by Nissan Chemical Industries, Ltd.) 9.3 g in this order, and then stirred for 24 hours in a 33 ° C. warm bath, colloidal silica and aluminum nitrate A gradient film coating solution (H) of a hydrolyzate of titanium alkoxide and an organic polymer component was prepared. At this time, the colloidal silica in the solid content of the coating liquid (H) was 20% by mass.

  Thereafter, the coating liquid (H) is applied to a 2 mm-thick colorless transparent acrylic plate (Mitsubishi Rayon, Acrylite L) having a refractive index of 1.49 using a spin coater with a wet thickness of about 10 μm, The dry thickness was applied to 100 nm. Then, the same operation as Example 1 was performed and the photocatalyst film | membrane which has a photocatalyst layer on the inclined film surface was produced. The refractive index of this photocatalyst film was 1.65. The obtained sample had a difference in haze value of less than 0.1% before and after coating, but the total light transmittance (Tt) decreased by 1.0%. In addition, no interference color was observed.

Comparative Example 2
8.75 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 61.2 g of ethyl cellosolve, and then the hydrolytic condensation liquid (C) of titanium alkoxide prepared in Synthesis Example 1 was added to 78 .8 g was added and stirred well to obtain a solution (G). Subsequently, 10.43 g of the organic polymer component solution (D) prepared in Synthesis Example 2, 239.6 g of methyl isobutyl ketone, 101.2 g of ethyl cellosolve, and 148.8 g of the solution (G) described above were mixed in this order. Then, it stirred for 24 hours with a 33 degreeC warm bath, and produced the inclination film | membrane coating liquid (H) of the hydrolyzate of the titanium alkoxide which mixed aluminum nitrate, and the organic polymer component. This coating liquid (H) solid content does not contain colloidal silica.

  Thereafter, the coating liquid (H) is applied to a 2 mm-thick colorless transparent acrylic plate (Mitsubishi Rayon, Acrylite L) having a refractive index of 1.49 using a spin coater with a wet thickness of about 10 μm, The dry thickness was applied to 100 nm. Then, the same operation as Example 1 was performed and the photocatalyst film | membrane which has a photocatalyst layer on the inclined film surface was produced. The refractive index of this photocatalyst film was 1.75. The obtained sample had a difference in haze value of less than 0.1% before and after coating, but the total light transmittance (Tt) decreased by 2.0%. In addition, generation of interference colors was observed.

Comparative Example 3
In the same manner as in Example 2, a gradient film coating liquid (H) was obtained.
Thereafter, the coating liquid (H) is applied to a 100 μm-thick colorless transparent polyester film (Lumirror T60, manufactured by Toray, Inc.) having a refractive index of 1.66 with a wet thickness of about 10 μm using a spin coater, and a dry thickness. Was applied to a thickness of 100 nm. Then, the same operation as Example 1 was performed and the photocatalyst film | membrane which has a photocatalyst layer on the inclined film surface was produced. The refractive index of this photocatalyst film was 1.35. The obtained sample had a difference in haze value of less than 0.1% before and after coating, but the total light transmittance (Tt) was improved by 1.5%. However, the occurrence of interference color was recognized although it was slight.

Comparative Example 4
Next, 6.12 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 42.9 g of ethyl cellosolve, and then the hydrolytic condensation liquid (C) of titanium alkoxide prepared in Synthesis Example 1 was 55. .2 g was added and stirred well to obtain a solution (G). Subsequently, 7.30 g of the organic polymer component solution (D) prepared in Synthesis Example 2, 235.8 g of methyl isobutyl ketone, 138.9 g of ethyl cellosolve, 104.15 g of the solution (G) described above, and colloidal silica A ( Product name: Snowtex IPA-ST (average particle size 20 nm), manufactured by Nissan Chemical Industries, Ltd. 2.3 g, colloidal silica C (product name: Snowtex IPA-ST-ZL (average particle size 100 nm), Nissan Chemical (Industry Co., Ltd.) 11.6 g in order, then stirred in a warm bath at 33 ° C. for 24 hours, and the gradient of titanium alkoxide hydrolyzate mixed with colloidal silica and aluminum nitrate and organic polymer component A film coating solution (H) was prepared. At this time, the colloidal silica in the solid content of the coating liquid (H) was 30 mass%, colloidal silica C / colloidal silica A = 83/17 (mass ratio).

  Thereafter, the coating liquid (H) is applied to a 100 μm-thick colorless transparent polyester film (Lumirror T60, manufactured by Toray, Inc.) having a refractive index of 1.66 with a wet thickness of about 10 μm using a spin coater, and a dry thickness. Was applied to a thickness of 100 nm. Then, the same operation as Example 1 was performed and the photocatalyst film | membrane which has a photocatalyst layer on the inclined film surface was produced. The refractive index of the coating film at this time was 1.59. The obtained sample had a specific surface area of 1.0010 as measured by AFM (Keyence Co., Ltd., VN8000). Before and after coating, the total light transmittance (Tt) was improved by 2.0%, but the haze value was increased by 0.4%. In addition, no interference color was observed.

Comparative Example 5
Next, 6.12 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 42.9 g of ethyl cellosolve, and then the hydrolytic condensation liquid (C) of titanium alkoxide prepared in Synthesis Example 1 was 55. .2 g was added and stirred well to obtain a solution (G). Subsequently, 7.30 g of the organic polymer component solution (D) prepared in Synthesis Example 2, 235.8 g of methyl isobutyl ketone, 138.9 g of ethyl cellosolve, 104.15 g of the solution (G) described above, and colloidal silica C ( Product name: Snowtex IPA-ST-ZL (average particle size 100 nm), manufactured by Nissan Chemical Industries, Ltd.) 13.9 g in this order, then stirred in a warm bath at 33 ° C. for 24 hours, colloidal silica and A gradient film coating solution (H) of a hydrolyzate of titanium alkoxide mixed with aluminum nitrate and an organic polymer component was prepared. At this time, the colloidal silica in the solid content of the coating liquid (H) was 30% by mass.

  Thereafter, the coating liquid (H) is applied to a 100 μm-thick colorless transparent polyester film (Lumirror T60, manufactured by Toray, Inc.) having a refractive index of 1.66 with a wet thickness of about 10 μm using a spin coater, and a dry thickness. Was applied to a thickness of 100 nm. Then, the same operation as Example 1 was performed and the photocatalyst film | membrane which has a photocatalyst layer on the inclined film surface was produced. The photocatalytic film had a refractive index of 1.59. The obtained sample had a specific surface area of 1.0060 as measured by AFM (VN8000, manufactured by Keyence Corporation). Before and after coating, the total light transmittance (Tt) was improved by 2.0%, but the haze value was increased by 0.6%. In addition, no interference color was observed.

Comparative Example 6
Next, 6.12 g of aluminum nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 42.9 g of ethyl cellosolve, and then the hydrolytic condensation liquid (C) of titanium alkoxide prepared in Synthesis Example 1 was 55. .2 g was added and stirred well to obtain a solution (G). Subsequently, 7.30 g of the organic polymer component solution (D) prepared in Synthesis Example 2, 235.8 g of methyl isobutyl ketone, 138.9 g of ethyl cellosolve, 104.22 g of the solution (G) described above, and colloidal silica A ( Product name: Snowtex IPA-ST (average particle size 20 nm), manufactured by Nissan Chemical Industries, Ltd. 12.8 g, colloidal silica D (product name: MP-2040 (average particle size 190 nm), Nissan Chemical Industries, Ltd.) (Product made) In the order of 0.83 g, and then stirred in a warm bath at 33 ° C. for 24 hours, a gradient coating solution of a hydrolyzate of titanium alkoxide mixed with colloidal silica and aluminum nitrate and an organic polymer component ( H) was produced. At this time, colloidal silica in the solid content of the coating liquid (H) was 30% by mass, and colloidal silica D / colloidal silica A = 8/92 (mass ratio).

Thereafter, the coating liquid (H) is applied to a 100 μm-thick colorless transparent polyester film (Lumirror T60, manufactured by Toray, Inc.) having a refractive index of 1.66 with a wet thickness of about 10 μm using a spin coater, and a dry thickness. Was applied to a thickness of 100 nm. Then, the same operation as Example 1 was performed and the photocatalyst film | membrane which has a photocatalyst layer on the inclined film surface was produced. The photocatalytic film had a refractive index of 1.59. As a result of measuring the specific surface area of the obtained sample with AFM (manufactured by Keyence Corporation, VN8000), it was 1.0030. Before and after coating, the total light transmittance (Tt) was improved by 1.0%, but the haze value was increased by 0.7%. In addition, no interference color was observed.
The results of Examples 1 to 8 and Comparative Examples 1 to 6 are shown in Table 1.

［注］
ＰＭＭＡ：厚さ２ｍｍの無色透明アクリル板、屈折率１．４９
ＰＣ ：厚さ２ｍｍの無色透明ポリカーボネート板、屈折率１．５９
ＰＥＴ ：厚さ１００μｍの無色透明ポリエチレンテレフタレートフィルム、
屈折率１．６６

[note]
PMMA: colorless transparent acrylic plate with a thickness of 2 mm, refractive index of 1.49
PC: colorless transparent polycarbonate plate with a thickness of 2 mm, refractive index of 1.59
PET: colorless and transparent polyethylene terephthalate film having a thickness of 100 μm,
Refractive index 1.66

  As can be seen from Table 1, in the organic base material on which the photocatalyst film of the present invention (Examples 1 to 8) was formed, the increase in haze value was suppressed to 0.2% or less before and after the photocatalyst film formation. In both cases, the total light transmittance increased by 0.5 to 1.5% except for Example 1, and no interference color was observed.

  On the other hand, the organic base material on which the photocatalyst films of Comparative Examples 1 to 6 are formed has a reduced total light transmittance or a haze value of 0.4 to 0.7% before and after the photocatalyst film formation. Increase or interference color is observed.

  The photocatalyst film of the present invention is formed on an organic base material by a one-coating method and has excellent hydrophilic performance, but exhibits almost no decomposition activity and suppresses an increase in haze value of the organic base material. , The reflectance can be lowered and the transparency can be improved.

Claims (8)

Content of hydrolysis condensate of titanium alkoxide provided by applying a coating agent containing a complex formed by hydrolysis and condensation of titanium alkoxide and organic polymer compound only once on an organic base material Is a photocatalytic film obtained by exposing the surface of an amorphous titanium oxide film whose surface continuously changes in the depth direction from the surface to a temperature of 100 ° C. or less in the presence of water vapor,
(1) The difference between the refractive index of the organic base material and the refractive index of the photocatalytic film surface is expressed by the following relational expression (1):
0 ≦ refractive index of organic base material−refractive index of photocatalytic film surface <0.25 (1)
And (2) the photocatalyst film, in addition to the photocatalyst particles, metal oxide particles A having an average particle size of less than 40 nm, metal oxide particles B having an average particle size of 40 nm or more and less than 80 nm, and an average particle size of 80 nm or more The metal oxide particles C of less than 150 nm have a mass ratio of A to B of 100: 0 to 0: 100, or a mass ratio of A to C of 100: 0 to 45:55. Including to be,
A photocatalytic film characterized by   2. The photocatalytic film according to claim 1, which is a photocatalytic film obtained by heat-treating the surface of an amorphous titanium oxide film coated on an organic base material at a temperature of 100 ° C. or lower in the presence of moisture. .   The photocatalyst film according to claim 1 or 2, wherein the metal oxide particles A to C other than the photocatalyst particles are silica fine particles and / or rutile-type titanium oxide fine particles.   The photocatalyst film according to claim 3, wherein the metal oxide particles A to C are silica fine particles.   The photocatalyst film according to any one of claims 1 to 4, wherein the refractive index of the photocatalyst film surface is adjusted by controlling a mixing ratio of the metal oxide particles A to C.   The photocatalyst film according to any one of claims 1 to 5, wherein an increase in haze value before and after the formation of the photocatalyst film, measured in accordance with JIS K 7361, is 0.2% or less.   An article comprising the photocatalyst film according to any one of claims 1 to 6 on the surface of an organic base material.   The article according to claim 7, further comprising a functional film on the surface of the photocatalytic film.