JP2006083363A - Coating material and use of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating material capable of forming a film equipped with a sufficient film strength and photo-catalytic function jointly by an easy procedure. <P>SOLUTION: This coating material is provided by containing a particle group A, a particle group B and a solvent, and the number of necking particles of the particle group A [the total number of particles constituting all of the necking particles by using individual particles necking each other as a unit particle, and hereinafter the same is applied] is larger than the number of the necking particles in the particle group B. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coating material, a manufacturing method thereof, a film manufactured using the coating material, and the use thereof, which are used for a photocatalytic film having high performance.

  As a method generally used for film formation, there are a dry process and a wet process. Examples of the dry process include those performed in a vacuum vessel such as sputtering. Examples of the wet process include a film formed using a coating material, electrolysis deposition using a plating method, etc., or electroless deposition. Examples include membranes. Among these, the method of forming a film using a coating material, in particular, requires no special equipment such as vacuum equipment, is easy to perform post-installation, and can be used under similar conditions in a wide range from the experimental scale to the mass production stage. It has features such as that it can be used, and it is used to give articles a design using ink, paint, etc., or to provide functions such as photocatalyst and anticorrosion.

  In many cases, such a coating material binds the particle group H to be blended in order to have a desired function such as photocatalytic activity and the particle group H to have strength as a film. Component I, and a solvent J for using these as coating materials, an additive K for improving dispersion stability and coating properties as coating materials, and the like are blended.

  The binding component I is unnecessary at a relatively high temperature at which the particle group H is welded as described in Patent Document 1, but the technique using this high temperature is that the temperature at which the particle group H is welded is ceramics. If the product is already in a desired state, it is not only applicable to substrates with a high melting point that can withstand such high temperatures. There is a problem that the film forming condition of 300 ° C. or higher is not practical when it is desired to attach it or when it is applied to a large member such as a building material on site.

  Thus, since it may be difficult to obtain a film having a practical strength using only the particle group H without using the binder component I, generally, the strength is increased at a lower temperature. Organic or inorganic binder components I that can be used are used.

JP 07-155598 A WO01 / 16027 pamphlet Japanese Patent Laid-Open No. 11-43327 Ceramic Engineering Handbook (Japan Ceramic Association, 1st edition) 596-598 pages Electrochemistry 70, 418. 2002 Journal of Material Chemistry Vol. 11, p. 1116, 2001

  As the ratio of the binding component I to the particle group H increases, the film can obtain strength. However, as the blending ratio of the binder component I increases, the photocatalytic ability of the particle group H, which was originally intended, is generally inhibited. Furthermore, the active point of the particle group H for the expression of the photocatalytic function is often a chemically unique point, and in particular, the binding component I often adheres preferentially. For this reason, the amount of the particle group H and the binder component I is in a trade-off relationship for the purpose of sufficiently exerting the strength of the film and the intended function of the film. In addition, the binder component I is often expensive with respect to the particle group H, and its extensive use is undesirable.

  In this way, the film formation method using the coating material is useful, but if the film strength is sufficiently increased, the concentration of a substance such as a binder which is not related to the expression of the function is increased. Inevitably, there was a problem of inhibiting the photocatalytic ability of the particle group H.

  The subject of this invention is providing the coating material which can form the film | membrane which has sufficient film | membrane intensity | strength and a photocatalytic function with an easy method.

  As a result of intensive studies on the coating material in order to solve the above problems, the inventors of the present invention studied and synthesized the necked particle group A and the particle group B with less necking, respectively, and by examining the formulation, The present invention was completed by finding that a coating material having excellent coating properties, capable of sufficiently exhibiting the function of the particle group H, and capable of forming a film strength that can withstand practical use can be obtained.

Thus, the present invention provides the following inventions.
(1)
The number of necking particles of the particle group A including the particle group A, the particle group B, and the solvent (the total number of particles constituting all necking particles, with each particle being necked as a unit. For example, m If there is one particle group in which one particle is necked and one particle group in which n particles are necked, the number of necking particles is m + n. The same shall apply hereinafter). Coating material characterized by having more than
(2)
A coating material comprising a metal oxide particle group A having a necking structure in which m particles are connected, a metal oxide particle group B having only 0.2 m particles or less, and a solvent.
(3)
The coating material according to (2) above, wherein the average primary particle diameter in terms of the BET specific surface area of the particle group A is 7 nm or more and 200 nm or less.

(4)
The coating material according to any one of (1) to (3) above, wherein the particle size distribution of the particle group A is a distribution constant of 1.5 or more according to the Rosin-Rammler equation.
(5)
The coating material according to any one of (1) to (4), wherein the particle group A contains titanium oxide.

(6)
The coating material according to any one of the above (1) to (5), wherein an average particle size measured using a laser diffraction particle size distribution analyzer of particle group A is 50 nm to 3 μm.
(7)
The coating material according to any one of (1) to (6) above, wherein the particle group A includes titanium oxide synthesized by a gas phase method in which titanium tetrachloride is oxidized at high temperature with an oxidizing gas.

(8)
Particle group A reacts after preheating a gas containing titanium tetrachloride and an oxidizing gas to 500 ° C. or higher, and the average primary particle diameter in terms of BET specific surface area is 7 nm or more and 500 nm or less. The coating material according to any one of (1) to (7), including titanium.
(9)
The particle group A contains titanium oxide synthesized by supplying a gas containing titanium tetrachloride preheated to 500 ° C. or more and an oxidizing gas to the reaction tube at a flow rate of 10 m / sec or more, respectively (1 The coating material according to any one of (8) to (8).

(10)
The titanium oxide of the particle group A retains the titanium tetrachloride-containing gas and the oxidizing gas in the reaction tube for a period of 1.0 second or less under a high temperature condition in which the temperature in the reaction tube exceeds 600 ° C. The coating material according to (9), which is synthesized by reacting in the above manner.
(11)
The coating material according to (9) or (10), wherein the titanium oxide of the particle group A is synthesized with an average flow rate of the gas in the reaction tube of 5 m / second or more.

(12)
Any one of the above (7) to (11), wherein the titanium oxide of the particle group A is synthesized by supplying a preheated titanium tetrachloride-containing gas and an oxidizing gas into the reaction tube to generate turbulence. The coating material according to item.

(13)
The coating material according to any one of (7) to (12), wherein the titanium oxide of the particle group A is synthesized by containing 10 to 100% of titanium tetrachloride in the gas containing titanium tetrachloride. .
(14)
The titanium oxide of the particle group A according to any one of (7) to (13), wherein the gas containing titanium tetrachloride and the temperature for preheating the oxidizing gas are synthesized at 800 ° C. or higher. Coating material.

(15)
The coating material according to any one of the above (1) to (14), wherein an average primary particle diameter of the particle group B according to a BET converted value is 4 nm or more and 100 nm or less.
(16)
The coating material according to (15), wherein the average particle diameter of the particle group B measured by a laser diffraction particle size distribution analyzer is 4 nm or more and 2000 nm or less.

(17)
The coating material according to (16), wherein an average particle size of the particle group B measured by laser Doppler particle size distribution measurement is 8 nm or more and 100 nm or less.
(18)
The coating material according to any one of (15) to (17), wherein the particle group B includes titanium oxide synthesized by hydrolyzing a titanium compound aqueous solution in water.

(19)
The coating material according to any one of (15) to (18), wherein the particle group B includes titanium oxide synthesized by a production method in which a titanium tetrachloride aqueous solution is dropped into water.
(20)
The coating material according to (19) above, wherein the titanium oxide of the particle group B is synthesized by a production method in which a titanium tetrachloride aqueous solution is dropped into water heated to a boiling point from 50 ° C.

(21)
The coating material according to any one of (1) to (20), wherein the ratio X / Y of the mass X of the particle group A and the dry mass Y of the particle group B is 0.01 or more and 0.2 or less.
(22)
The solid content concentration (X + Y) / Z is 0.005 or more and 0.1 or less when the mass X of the particle group A, the dry mass Y of the particle group B, and the mass Z of the entire coating material are (1) The coating material according to any one of to (21).

(23)
A coating material containing a metal oxide, comprising a particle group Ba having a peak at 8 nm or more and 400 nm or less and a particle group Aa having a peak at 800 nm or more and 5500 nm or less in a mass particle size distribution of a laser Doppler method.
(24)
The coating material according to (23), including a particle group Ba having a peak at 20 nm to 300 nm and a particle group Aa having a peak at 1200 nm to 4000 nm in the mass particle size distribution of the laser Doppler method.

(25)
In the laser Doppler method mass particle size distribution, when the integrated area of the particle group Ba is BaS and the integrated area of the particle group AaS is AaS, the ratio of AaS / BaS is 0.05 or more and 1 or less (23) or The coating material according to (24).

(26)
A coating material containing a metal oxide, which has a peak Ab at least 1 μ to 4 μm in the mass particle size distribution of the laser diffraction method, and has a primary particle diameter converted from a BET measurement value of a dry powder of the coating material The coating material which is 7 nm or more and 50 nm or less.
(27)
A coating material comprising titanium oxide synthesized by a gas phase method of producing titanium tetrachloride by oxidizing at high temperature with an oxidizing gas, titanium oxide synthesized by hydrolyzing a titanium compound aqueous solution in water, and a solvent.
(28)
The ratio of the dry mass of titanium oxide synthesized by a vapor phase method in which titanium tetrachloride is oxidized at high temperature with an oxidizing gas and titanium oxide synthesized by hydrolyzing a titanium compound aqueous solution in water is 0.01. The coating material according to (27), wherein the coating material is 0.2 or more and 0.2 or less.

(29)
The coating material according to any one of (1) to (28), comprising an inorganic binder.
(30)
The coating material according to any one of (1) to (29), comprising an organic binder.
(31)
The coating material according to (29), wherein the inorganic binder contains a zirconium compound.
(32)
The coating material according to any one of (1) to (31) above, which contains a fluorine-based resin.
(33)
The coating material according to (31) above, wherein the fluororesin contains polytetrafluoroethylene.
(34)
The coating material according to the above (32) or (33), wherein the particle size of the fluororesin is from 0.01 μm to 2 μm.
(35)
The coating material according to (34), wherein the particle size of the fluororesin is 0.05 μm or more and 0.5 μm or less.
(36)
The coating material according to any one of (32) to (35), further including a surfactant of 0.5% by mass or more and 10% by mass or less with respect to the weight of the fluororesin.
(37)
The coating material according to (36), wherein the surfactant is a nonionic one.
(38)
The coating material according to any one of (1) to (37), wherein a film having a strength of H or higher in a pencil strength test can be formed by heat drying at 200 ° C. or lower.
(39)
The coating material according to any one of the above (1) to (38), wherein the solid content in the coating material is 10% by mass or more.
(40)
The coating material according to any one of (1) to (39), wherein 50% by mass or more of the solid content is titanium oxide.
(41)
The coating material according to (40), wherein the solid content is 60% by mass or more of titanium oxide.
(42)
When the inorganic binder is Iw [g] in terms of 120 ° C. dry solids and the fluororesin is Fw [g] in terms of 120 ° C. dry solids, among the binders blended in the coating material The coating material according to any one of (32) to (41), wherein Iw / Fw is 0.05 or more and 20.0 or less.
(43)
The coating material according to any one of (1) to (42) above, which contains an anionic surfactant in an amount of 10 ppm to less than 2000 ppm.

(44)
The coating material according to any one of (1) to (42) above, which contains a cationic surfactant in an amount of 10 ppm or more and less than 2000 ppm.
(45)
The coating material according to any one of (1) to (42) above, which contains a nonionic surfactant in an amount of 2 ppm or more and less than 2000 ppm.
(46)
The coating material according to (45), comprising a nonionic surfactant in an amount of 2 ppm or more and less than 50 ppm.
(47)
The coating material according to any one of (1) to (46), wherein the solid material contains titanium oxide and a partially hydrolyzed product of alkoxysilane.
(48)
Any one of (1) to (47) above, comprising an inorganic binder and a ceramic fiber having a diameter of 0.5 to 10 μm with respect to titanium oxide and having a diameter of 0.5 to 10 μm. The coating material described.
(49)
It is applied to an area of 56.25 cm ² , contaminated in an irradiation environment at 10000 lux for 12 hours in air diluted SO ₂ gas at 20 ° C., 50% relative humidity, 5 L, 50 ppm, 20 ° C., 50% relative humidity, 500ml, 500ppm acetaldehyde gas removal test, coating that can create a photocatalytic film with b / a of 0.5 or more when the removal rate before contamination is a% and the removal rate after contamination is b% Wood.
(50)
At least one physical adsorbent selected from the group consisting of activated alumina, A-type zeolite, Y-type zeolite and activated carbon is blended in an amount of 10% by mass to 200% by mass with respect to the photocatalyst fine particles. The coating material according to any one of (1) to (49) above.
(51)
The coating material according to (50) above, wherein the activated alumina, A-type zeolite, Y-type zeolite, and activated carbon have a particle size of 5 nm or more and 5 μm or less.
(52)
The photocatalyst fine particles are contained, and at least one of copper oxide, iron oxide, manganese oxide, and zinc oxide is used as a chemical trapping material, and 0.01% by mass to 200% by mass or less in terms of metal with respect to the photocatalyst fine particles. The coating material according to any one of 1) to (51).
(53)
0.01% in terms of metal with respect to the photocatalyst fine particles, containing photocatalyst fine particles, and using at least one of alkaline earth metal chloride, alkaline earth metal carbonate, and alkaline earth metal hydrogen carbonate as a chemical trapping material The coating material according to any one of (1) to (52), which is contained in an amount of 200% by mass or less.
(54)
The coating material according to (53) above, wherein the alkaline earth metal chloride is calcium, strontium or barium chloride.
(55)
(1) to (54) above, which contain photocatalyst fine particles and contain one or more of nickel oxide, cobalt oxide and molybdenum oxide in an amount of 0.1% by mass to 200% by mass with respect to the photocatalyst particles. The coating material according to any one of the above.
(56)
The above (55), further comprising platinum metal or a platinum compound, wherein the sum of the weights of one or more of nickel oxide, cobalt oxide, and molybdenum oxide with respect to platinum is 20% by mass to 10,000% by mass. ) Coating material.
(57)
The coating material according to (55) or (56), wherein the d50 particle size of platinum, a compound thereof, and a transition metal oxide is 10 nm or more and 10 μm or less.

(58)
Manufacture of a coating material including a step of mixing a metal oxide particle group A having a necking structure in which m particles are connected, a metal oxide particle group B having only 0.2 m particles or less, and a solvent. Method.
(59)
After applying and drying the coating material according to any one of the above (1) to (56) having a solid content concentration of 5% by mass or more and less than 35% by mass, the solid content concentration is 1 / of that of the first coating material. A method for producing a film, in which a coating material containing 2% by mass or less of particle group B and a binder is applied and dried.
(60)
The film | membrane made from the coating material as described in any one of said (1)-(57).

(61)
The film according to (60), wherein the film has an average film thickness of 50 nm or more and 30000 nm or less.
(62)
The film according to (60), wherein the film has an average film thickness of 50 nm or more and 2000 nm or less.
(63)
The film according to (60), wherein the film has an average film thickness of 1/10 to 5 times the aggregate particle diameter of the particle group A.

(64)
Articles provided with the film according to any one of (60) to (63) above or inside.
(65)
An article having at least one function among photocatalytic functions such as deodorization, antifouling, and antibacterial.

(66)
Articles include building materials, lighting equipment, design window glass, machinery, vehicles, glass products, home appliances, agricultural materials, electronic equipment, mobile phones, tools, tableware, bath products, pure water production equipment, toilet articles, furniture, clothing , Cloth products, textiles, leather products, paper products, resin products, sports equipment, futons, containers, glasses, signs, piping, wiring, metal fittings, sanitary materials, automobile supplies, stationery, emblems, hats, bags, shoes, umbrellas, blinds , Balloons, piping, wiring, metal fittings, fluorescent lamps, LEDs, traffic lights, street lights, toys, road signs, ornaments, tents, cooler boxes, and other outdoor products, artificial flowers, objects, filters, deodorant filters The article according to (64) or (65), which is at least one selected from the above.

The present invention will be described in detail below.
A coating material according to a preferred embodiment of the present invention includes a particle group A composed of particles having many necking structures, a particle group B having little or no necking structure compared to the particle group A, and these particles. A solvent. That is, the present invention provides a coating material comprising the particle group A, the particle group B, and a solvent, wherein the number of necking particles in the particle group A is larger than the number of necking particles in the particle group B. In the coating material according to a preferred embodiment of the present invention, titanium oxide synthesized by a vapor phase method in which titanium tetrachloride is oxidized at high temperature with an oxidizing gas and a titanium compound aqueous solution are hydrolyzed in water. It comprises synthesized titanium oxide and a solvent. A feature of a preferred embodiment of the present invention resides in that an optimum amount of the particle group A having a structure in which particles are necked with each other is blended in the coating material. As an index for determining that the particle group A is necked, when the particle group is observed with a TEM as shown in FIG. In addition, there may be a portion where the particles are in contact with each other as in “a” and the titanium oxide is observed as a continuous particle.

  By using the coating material in a preferred embodiment of the present invention, it is possible to produce a coating material having desirable characteristics for forming a photocatalytic film as described below.

(a) A film having high strength can be formed One of the characteristics required as a photocatalyst film is high film strength. In the case where a photocatalyst is already in a state where a base material or product is present, the photocatalyst is often applied to the surface in order to add value to the base material or product. In this case, since the photocatalyst film is exposed to an environment in contact with the outside, the photocatalyst film is peeled off if it does not have sufficient strength, and the effect is not maintained.

  In the coating material according to a preferred embodiment of the present invention, the particle group A preferably has a necking structure. In this case, the photocatalytic film obtained from the coating material has a necking structure as shown in FIG. A point contacts the substrate surface and is fixed relative to the substrate. Thus, film | membrane intensity | strength improves by mix | blending the particle group A which has an effect as an anchor. As another effect, it is considered that the particle group A has a three-dimensional structure to reduce the degree of freedom of the particle group B, that is, an action as a framework for supporting the entire film structure.

(b) Possible to reduce the amount of binder component When the particle group having a necking structure is included, the amount of the binder component can be reduced by the amount having the necking structure, and the strength of the film is improved. The strength of the film is also improved for the reasons described above. For this reason, it is possible to form a film by reducing the amount of the binding component I compared with the conventional film formation or not using it at all. As a result, the inhibition of the binding component on the characteristics of the particle group H can be minimized or eliminated.

(c) A film having high photocatalytic ability can be formed In the coating material according to a preferred embodiment of the present invention, the binder amount can be reduced, so that the photocatalytic ability of the particle group H can be sufficiently exhibited. In the photocatalyst film, the liquid or gas to be decomposed needs to come into contact with the photocatalyst particle group H. For this purpose, the film needs to be porous. Furthermore, in order to increase the efficiency of charge separation of holes and electrons generated by excitation of the photocatalyst, high crystallinity is also required. In the preferred embodiment of the present invention, since the particles having necking are continuous with adjacent particles without losing the properties as particles, a photocatalytic film having a crystal order longer than a single particle is formed. Allows to form. As a continuous photocatalyst component, there is a method of adding a metal oxide nanotube (Non-patent Document 2) or the like. However, although the crystallinity is improved by the nanotube, the chemically active characteristic is generally difficult to appear on the side wall of the tube structure. Therefore, the particle group A in which the particles have a necking structure is more desirable as a photocatalyst film because the surface active as a photocatalyst is on the surface. In addition, the particle group A in a preferred embodiment of the present invention may have a feature that the aggregated particle diameter is larger than the average film thickness, and a part of the particle group having a high photocatalytic activity protrudes from the film. Therefore, it is considered possible to have high photocatalytic performance as a film.

(d) A film with high transparency and no interference color can be formed Generally, when the size of the particles blended during film formation exceeds 1/2 of the wavelength of light, light interference or scattering occurs, resulting in interference color. Appears or is white. In the particle group A in the present invention, even when the average particle diameter of the aggregated particles is increased to 1 μm to 2 μm by necking, the primary particle diameter D1 is sufficiently small with respect to the wavelength in the visible light region. I can't see it. Furthermore, it should be noted that when a film is formed using the coating material of the present invention, no interference color appears on the film. When a film is formed using only the particle group B with little necking and is formed to a thickness of 100 nm or more and 1 μm or less, it is difficult to avoid the generation of interference colors. When the coating material of the present invention is used, the detailed mechanism is unknown, but it has a feature that interference color does not appear even in a film thickness of 200 nm or more and 800 nm or less, which is a range in which interference color is observed very strongly. This is considered to be because particles having a diameter exceeding 1 μm as the aggregated particle diameter are contained in the particle group A, and some of the aggregated particles protruding from the film-formed surface are rough on the surface. By controlling the degree appropriately, it is considered that the film works to prevent interference of light that occurs in the case of a smooth film.

(e) Improvement of coatability As the characteristics required for photocatalyst coating materials, each of the above items has been described so far, but simultaneously with the performance as a photocatalyst, it is easy to get wet, and thixotropic properties that prevent uneven coating, Leveling is also necessary. In consideration of wetting and dispersion of the particle group, when the particle group H is, for example, a titanium oxide system, a solvent having a relatively high vapor pressure at room temperature such as alcohol is often used. At this time, it is difficult to control the drying of the coating material after coating if it contains only the particle group B so as to be about 5% in terms of solid content. This leads to a decrease in strength and design. On the other hand, in the coating material containing the particle group A in a preferred embodiment of the present invention, thixotropy, leveling, and retention of the liquid after coating are excellent, and generation of liquid dripping traces due to unevenness in drying depending on the part. Can be prevented. Although the factors that can improve the above characteristics and prevent rapid drying when the particle group A is blended are not clear, the complex necking structure of the particle group A is the coating property of the coating material. It is thought to be responsible for improvement and liquid retention.

(f) Reduction of tackiness Generally, a photocatalyst film has high tackiness, and when the surface of the film is traced by hand, it feels caught. This is considered to be due to the chemical affinity and physical interaction between the photocatalyst surface and the hand. For this reason, if the photocatalyst film is highly tacky, it may cause peeling even if it is as soft as a hand. The strength test of the photocatalyst film includes a pencil strength test that assumes contact with a pointed object. In this pencil strength test, even if the film has sufficient strength, it is rubbed by hand if it has tackiness. And may peel off. In the film containing the particle group A of the present invention, this tackiness is reduced, and peeling when rubbed by the surface hardly occurs. Although the mechanism for reducing tackiness is not clear, a mechanism in which a part of the particle group A protrudes from the film and prevents a medium that rubs against a smooth film by the particle group B, for example, palms from contacting each other. Is considered to work.

  As described above, the characteristic point in the preferred embodiment of the present invention is that the particle group A is contained in the coating material. The coating material may have a low viscosity such as spray coating, dip coating, or flow coating, or may have a high viscosity that can be applied by a squeegee method or a doctor blading method.

  It is preferable that the particle group A and the particle group B have an appropriate degree of necking. In a system in which the particle group A, the particle group B, and the binder component are present, it can be confirmed that a laser Doppler type particle size distribution measuring instrument has at least two particle size distribution peaks. In the present invention, this particle size distribution is preferably defined using ELS-800 (Otsuka Electronics Co., Ltd.). The measurement method is shown below. The measurement sample was diluted with special grade ethanol (Kanto Chemical Co., Ltd.) so that the powder concentration would be 0.07% by mass, and 150 ml of this solution was placed in a 200 ml PYLEX glass container, and the ultrasonic washer uchi ultrasonic cleaner VS-70U. A sample is obtained by performing irradiation for 1 minute using (output 65 W, water tank capacity 800 ml). The liquid sample is put into a polystyrene square cell Ultra-Vu Disposable Cuvettes (manufactured by Elkay) having an inner dimension of 10 mm square, and measurement is performed. Each variable set at the time of measurement is as follows.

  The measurement system is a constant temperature of 25 ° C., and the Marcat method is used for the distribution analysis. The number of integration is 100. The measurement mode uses the time interval method. The sampling time is 20 μsec, and the number of acquisition channels is 512. Using the homodyne method, the optimal light quantity is set to 10,000, the minimum light quantity is set to 5000, and the maximum light quantity is set to 20000. The analysis is performed assuming that the viscosity of ethanol is 1.10 cP, the refractive index is 1.3595, and the relative dielectric constant is 24.5. In the initial setting of the apparatus, the result on the coarse grain side becomes smaller due to the dust cut function, but in this measurement, the particle group A may appear in a part of several μm, so this dust cut function is turned off. To do. The measurement is started when the intensity variation is within 20% at 100 counts using the scattering intensity monitor. The ratio between the particle groups A and B is determined by integrating the mass distribution of particles.

  The particle group A (Aa) having a relatively large particle size, which is defined by the above method, retains the structure and exhibits the characteristics as described above so that the particle size distribution in the coating material is 800 nm. The above is desirable. If it is too large, it will protrude from the film and cause peeling of the film, so it is desirable to show a particle size distribution having a peak at 5500 nm or less in the coating material. However, since the particle groups showing these particle size distributions are sheared and wrinkled at the time of coating, there is a possibility that they are present only as particles smaller than this in the coating film. Moreover, it is desirable that the particle group B (Ba) having a relatively small particle diameter is present in the coating material at 8 nm or more and 400 nm or less. Since this particle group plays a role of entering the voids of the particle group A, it is desirable that the particle group is close to the primary particle. However, since this coating material contains a binder component, it is actually present in the state of primary particles completely. It is difficult to measure the particle size, and the particle size may be several tens of times larger than the primary particles with aggregation. The peak position of the particle size distribution of the particle group A is more desirably 1200 nm or more and 4000 nm or less, and the peak position of the particle size distribution of the particle group B is more desirably 20 nm or more and 300 nm or less.

  Regarding the particle group A (Aa) contained in the coating material, the particle size distribution can be defined using a laser diffraction particle size distribution analyzer SALD-2000J (manufactured by Shimadzu Corporation). The peak due to the particle group B observed when using a laser Doppler particle size distribution meter may not be clearly observed, probably because it is close to the lower limit of particle size measurement when using a laser diffraction type distribution meter. Can be defined at least in the particle group A (Aa) contained in the coating material. The measuring method of the diffractive particle size distribution analyzer is as follows.

  A sample is diluted with special grade ethanol so that it may become 0.05 mass%, and this diluted sample is thrown into a measurement system until the diffracted light intensity reaches a measurement region with SALD-2000J. At this time, the measurement system is sufficiently replaced with ethanol in advance. As the refractive index of the powder, analysis was performed with 2.50-0.1i (i is an imaginary number).

  When the particle group in the present invention is measured by the above method, the volume particle size distribution has a peak at least 1 μm to 4 μm. When it has a peak at 1 μm or more, the coating material tends to exhibit the characteristics (a) to (f) in the present invention. However, if it exceeds 4 μm, the particles may protrude from the film made from the coating material and cause peeling. In order to sufficiently exhibit the characteristics (a) to (f), the thickness is more preferably 1.2 μm or more and 3 μm or less.

The particles in the coating material according to a preferred embodiment of the present invention are composed of a material having a lot of necking structure and a material having little necking structure. It is preferable that the average primary particle converted from the BET specific surface area is 7 nm or more and 50 nm or less. The calculation method is shown by the following formula (2). Production of particles smaller than 7 nm may be accompanied by production difficulties. If it exceeds 50 nm, the haze of the film prepared from the coating material increases, and the characteristics of the film may be impaired.
As a technique for producing these coating materials, it is possible to mix the raw material of the particle group A and the raw material of the particle group B.

  When m particle groups A have a necking structure, the particle group B is connected only by ½ or less of the number of particles (0.5 m or less of particles). It is preferable that the number of particles is only 1/5 or less (0.2 m or less). Regarding the particle group B, the object in the present invention is achieved even when the necking is not performed at all and the primary particles are present as they are. That is, the average number of necking particles in the particle group B is preferably 0.000000001 m to 0.2 m, and more preferably 0.0000001 m to 0.1 m. The number of the particle groups A that are necked may be determined by observing with a microscope such as TEM or SEM, but the number is very large and the field of view of the microscope is limited. For this reason, the particle diameter DL (so-called D50 value) by a laser diffraction particle size distribution meter, the tap density Ρ (measured value by JIS K-51012-20.2), the primary particle diameter D1 by the BET method, and the true density of titania are expressed as ρ. , The number m of necking is determined by the following method.

  In the measurement of the DL value of the raw material powder, a laser diffraction type particle size distribution meter is used similarly when measuring the particle size distribution of the coating material, but since the target is powder, the method is shown below Use a different one.

  100 μl of a 10% sodium hexametaphosphate aqueous solution is added to 50 ml of a water slurry containing 0.05 g of titanium oxide in terms of powder, and subjected to ultrasonic irradiation (46 KHz, 65 W) for 3 minutes. About this slurry, a particle size distribution is measured using the laser diffraction type particle size distribution measuring apparatus (Shimadzu Corporation SALD-2000J).

  Further, the particle diameter D1 of the primary particles of the particle group A or the particle group B is an average primary particle diameter obtained from the formula (2) by converting the specific surface area obtained by the BET method into a spherical shape.

D1 = 6 / ρS (wherein ρ is the true density of the particles and S is the specific surface area of the particles) (2)
The number of the necked particles in the particle group B can be analyzed by particle size distribution, TEM, etc., but it is preferable to measure the particle size distribution. The particle size of the particles of the particle group B may be close to the lower limit value of the measurement range in the laser diffraction method, and the above-described laser Doppler particle size distribution measuring device is used for accurate analysis. The sample preparation method is also performed in the same manner as when using the above-described ELS-800. However, the sol is not dried particles, but is used as a measurement sample by diluting it in the sol state to a specified concentration. The number m of the necking is obtained from the equation (1), where DL is the particle diameter at which the scattered light intensity is strongest, and the tap density of the dry powder is Ρ.

The particle groups A and B in the present invention are aggregated when the particle size distribution is measured alone as the particle group A and when the particle size distribution is measured by mixing the particle groups A and B and, if necessary, the binder. The state is often different.
The average primary particle size of the particle group A calculated from the formula (2) is preferably 7 nm or more and 200 nm or less. Although it can be used even if it is less than 7 nm, the productivity of the particle group A may deteriorate and the cost may increase. Even if the particle diameter exceeds 200 nm, it can be used, but the degree of light scattering increases, and it may be difficult to obtain a transparent film from a coating material containing this.

  The particle sizes of the particle group A and the particle group B often have different distributions, and it is desirable that the raw material of the particle group A has a certain degree of uniformity especially in consideration of packing and film uniformity. .

The uniformity of the particle size can be defined by its distribution constant (n) using the Rosin-Ramler equation. Hereinafter, the Rosin-Rammler type will be briefly described, and details thereof are described in Non-Patent Document 1.
The Rosin-Rammler formula is represented by the following formula (3).

R = 100exp (−bD ⁿ ) (3)
However, in the formula, D represents a particle size, R is a percentage of the number of particles larger than D (particle size) with respect to the total number of particles, and n is a distribution constant.

Here, if b = 1 / De ⁿ , the equation (3) is R = 100exp {− (D / De) ⁿ } (4)
Can be rewritten as However, De is a particle size characteristic number, and n is a constant called a distribution constant.
From the formula (3) or the formula (4), the following formula (5) is obtained.

log {log (100 / R)} = nlogD + C (5)
However, in the formula, C represents a constant. From the above equation (5), when the relationship is plotted on a Rosin-Rammler (RR) diagram with log D on the x-axis and log {log (100 / R)} on the y-axis, it becomes a substantially straight line. The slope (n) of the straight line represents the degree of uniformity of the particle size, and it is judged that the larger the numerical value of n, the better the particle size uniformity.

  The fine particle titanium oxide used as a raw material for the present invention preferably has a 90% cumulative mass particle size distribution diameter D90 of 4 μm or less, more preferably 3 μm or less, and a distribution constant n of 1.5 or more according to the Rosin-Rammler equation. Preferably, it is 1.8 or more and 20 or less.

  A metal oxide particle group obtained by a so-called gas phase method in which a metal halide or the like is reacted with an oxidizing gas such as oxygen at a high temperature has high crystallinity due to a high thermal history during synthesis and has a necking bond. The gas phase method is preferable as the metal oxide structure of the present invention when used as the particle group A or the particle group B because a powder having a relatively narrow particle size distribution of primary particles is obtained as compared with other production methods. Easy to obtain primary particle size distribution. The primary particle size of the particle group A used in the present invention is not particularly limited, but is 7 to 200 nm, preferably 7 to 150 nm, and more preferably 10 to 100 nm. If the particle group A is a metal compound particle exhibiting photocatalytic activity, zinc oxide, titanium oxide, zirconium oxide, cadmium sulfide, potassium tantalate, strontium titanate, cadmium selenide, niobium oxide, iron oxide, tungsten oxide, tin oxide, etc. Although there is no particular limitation, titanium oxide having high catalytic ability and low toxicity is desirable.

  The vapor phase titanium oxide preferably used in the present invention is not particularly limited, but preferably contains anatase type crystals or brookite type crystals. When an anatase type crystal is contained, it may contain a rutile type titanium oxide in addition to anatase type titanium oxide alone. When the rutile type titanium oxide is optionally included in addition to the anatase type titanium oxide, the ratio of the anatase type in the titanium oxide is not particularly limited, but is usually 1 to 100% by mass, preferably 20 to 100% by mass. %, More preferably 50 to 100% by mass. This is because anatase-type titanium oxide is easier to disperse in a liquid and is easy to use as a raw material for a coating material.

  A general method for producing titanium oxide by a vapor phase method is known and is not particularly limited, but titanium tetrachloride is reacted at about 1,000 ° C. using an oxidizing gas such as oxygen or water vapor. Oxidation under conditions gives fine titanium oxide. As a preferable reaction form, the production method according to Patent Document 2 can be exemplified. Hereinafter, the method for producing titanium oxide as a raw material in the present invention will be described more specifically.

  There are roughly two types of particle growth mechanisms in the vapor phase method, one is CVD (chemical vapor deposition), and the other is particle growth (coalescence) or growth by sintering. In order to obtain ultrafine titanium oxide as the object of the present invention, it is preferable to shorten any particle growth time. That is, in the former growth, the growth can be suppressed by increasing the chemical reactivity (reaction rate) by increasing the preheating temperature. In the latter growth, the growth due to sintering or the like can be suppressed by cooling, diluting, etc. immediately after the CVD is completed, and minimizing the high temperature residence time.

In a gas phase method for producing titanium oxide by oxidizing titanium tetrachloride-containing gas at high temperature with an oxidizing gas, when the titanium tetrachloride-containing gas and the oxidizing gas are each preheated to 500 ° C. or higher, This is preferable because the growth of CVD can be suppressed. Fine particle titanium oxide having a BET specific surface area of 3 to 200 m ² / g, more preferably 50 to 150 m ² / g, can be obtained and used as a raw material.

  The gas containing titanium tetrachloride as a raw material preferably has a titanium tetrachloride concentration in the gas of 10 to 100%, more preferably 20 to 100%. When a gas having a titanium tetrachloride concentration of 10% or more is used as a raw material, the generation of uniform nuclei increases or the reactivity increases, so that it is difficult to form particles grown under the control of CVD, and particles having a narrow particle size distribution are formed. can get.

  Further, it is preferable to select a gas that does not react with titanium tetrachloride and is not oxidized as a gas for diluting titanium tetrachloride in the gas containing titanium tetrachloride. Specifically, nitrogen, argon, etc. are mentioned as preferable dilution gas.

  The preheating temperature of the gas containing titanium tetrachloride and the oxidizing gas is preferably 500 ° C. or higher, more preferably 800 ° C. or higher. When the preheating temperature is lower than 500 ° C., the generation of uniform nuclei is small and the reactivity is low, so that the particles have a broad particle size distribution.

  The flow rate when introducing the gas containing titanium tetrachloride and the oxidizing gas into the reaction tube is preferably 10 m / sec or more. This is because by increasing the flow velocity, mixing of both gases is promoted. More preferably, it is 20 m / sec or more and 200 m / sec or less, More preferably, it is 50 m / sec or more and 150 m / sec or less. If the introduction temperature of the gas into the reaction tube is 500 ° C. or higher, the reaction is completed simultaneously with the mixing, so that the generation of uniform nuclei is promoted, and the zone in which the grown particles are formed under the control of CVD can be shortened. it can.

  The source gas is preferably introduced into the reaction tube so that the gas introduced into the reaction tube is sufficiently mixed. If the gas is sufficiently mixed, the fluid state of the gas in the reaction tube is not particularly limited. However, for example, a fluid state in which turbulent flow occurs is preferable. Moreover, a swirl flow may exist.

  In addition, as an introduction nozzle for introducing the raw material gas into the reaction tube, a nozzle that provides a coaxial parallel flow, an oblique alternating current, a cross flow, or the like is employed, but is not limited thereto. In general, a coaxial parallel flow nozzle is inferior to a nozzle that gives oblique alternating current or cross flow, but is preferably used because of its simple structure.

  For example, in the case of a coaxial parallel flow nozzle, it is preferable to introduce a gas containing titanium tetrachloride into the inner tube. However, the inner tube diameter is preferably 50 mm or less, more preferably 30 mm or less from the viewpoint of gas mixing.

  The flow rate of the gas introduced into the reaction tube is preferably large in order to completely mix the gases, and in particular, the average flow rate is preferably 5 m / second or more, more preferably 8 m / second or more. . If the flow rate of the gas in the reaction tube is 5 m / sec or more, mixing in the reaction tube can be sufficiently performed, and the generation of particles grown under the control of CVD is small, and broad particles with a particle size distribution are generated. Absent.

This reaction in the reaction tube is an exothermic reaction, and the reaction temperature is higher than the sintering temperature of the produced fine particle titanium oxide. Although there is heat dissipation from the reaction apparatus, the produced fine particles are sintered and become grown particles unless they are rapidly cooled after the reaction. When obtaining ultrafine titanium oxide of less than 10 m ² / g, the high temperature residence time exceeding 600 ° C. in the reaction tube is preferably 1 second or less, more preferably 0.5 seconds or less, and then it is preferably rapidly cooled. As a means for rapidly cooling the particles after the reaction, introduction of a large amount of cooling air, a gas such as nitrogen, or spraying of water into the mixture after the reaction is employed.

  If the value of 90% cumulative mass particle size distribution diameter D90 of the particle size distribution of the synthesized titanium oxide measured by the above-described measurement method is small, it is judged that the dispersibility is good for the hydrophilic solvent. Furthermore, the fine particle titanium oxide produced by such a method is excellent in the uniformity of the particle size. Moreover, it is preferable that the fine particle titanium oxide used as a raw material used in the present invention has an anatase type crystal or a brookite type crystal as a main phase.

  In the preferred embodiment of the present invention, the raw material of the particle group A is desirably produced continuously in the titanium oxide synthesis process. One reason is production cost. Further, when necking is continuously performed when a titanium oxide crystal is generated at around 1000 ° C., adjacent particles are synthesized under substantially the same conditions, and are necked as they are, so that particles in a state where crystals are further continuous A is expected to form favorably. When the particles are put in a container instead of a continuous process and baked, the particles are easily welded to form a lump, so that the object of a porous body is hardly achieved.

  The coating material in a preferred embodiment of the present invention exhibits its characteristics by the interaction between the particle group A and the particle group B described so far.

  The titanium oxide that is preferably used as the raw material of the particle group B is not particularly limited, and examples thereof include the synthesis methods described below.

  The raw material of the particle group B can be manufactured by the method described in Patent Document 3. Among these, the synthesis of sols containing brookite crystals with good dispersibility is presumed that the intermediates go through chlorides as described in Non-Patent Document 3, and the chlorine concentration and temperature during synthesis are estimated. Control is important. For this reason, it is preferable to use what used the raw material titanium tetrachloride which generate | occur | produces hydrogen chloride by hydrolysis, More preferably, it is preferable to use the titanium tetrachloride aqueous solution. In order to keep the chlorine concentration at the time of synthesis at an optimum value, the scattering of hydrogen chloride outside the system may be prevented by techniques such as pressurization, but the most effective method is to install a reflux condenser in the hydrolysis reaction tank. This is a technique for performing hydrolysis. By adjusting the hydrochloric acid concentration and water concentration in an organic solvent, brookite crystal type titanium oxide can be obtained from a metal alkoxide raw material, but considering the ease of reaction control and the price of the raw material, The reaction medium is preferably water.

  The temperature in the hydrolysis is preferably 50 ° C. or higher and the boiling point of the titanium tetrachloride aqueous solution. Below 50 ° C., the hydrolysis reaction takes a long time. The hydrolysis is carried out by raising the temperature to the above temperature and holding it for about 10 minutes to 12 hours. This holding time may be shorter as the hydrolysis temperature is higher. Hydrolysis of the titanium tetrachloride aqueous solution may be performed by heating a mixed solution of titanium tetrachloride and water to a predetermined temperature in the reaction vessel, or by preheating water in the reaction phase, May be added to a predetermined temperature. By this hydrolysis, brookite crystal-containing titanium oxide can be obtained. In order to increase the content of brookite-type titanium oxide, water is heated in advance from 75 ° C. to the boiling point in a reaction vessel, and titanium tetrachloride is added to this in a temperature range from 75 ° C. to the boiling point. A method of hydrolysis is suitable. The finer the titanium oxide particles of the brookite crystal-containing titanium oxide sol, the better the transparency of the titanium oxide thin film. Moreover, it is preferable that it is crystalline from the point of a solvophilic effect | action.

However, since obtaining fine titanium oxide particles may be difficult in production, the BET specific surface area of the titanium oxide particles in the sol is preferably ²⁰ to 400 m ² / g. More preferably 50~350m ² / g, even more preferably 120m ² / g~300m ² / g. The average primary particle diameter calculated from the BET specific surface area is preferably 4 nm to 100 nm, more preferably 5 nm to 70 nm. More preferably, it is 5 nm-40 nm. Particle group B may be blended as a sol when blended into a coating material, or may be blended once dried, but from the viewpoint of dispersibility of the entire coating material, it is blended into the coating material as a sol. It is desirable that

  The brookite crystal-containing titanium oxide sol immediately after synthesis may coagulate and settle if the ionic strength remaining in the liquid is high, but the synthesized brookite crystal-containing titanium oxide sol may be subjected to electrodialysis desalination equipment or ultrafiltration. Dispersibility can be made more complete by passing through a washing step such as filtration using a membrane. Since it is considered that the particle group B enters the voids of the particle group A during film formation as shown in FIG. 2 and forms a film, it is preferable that the aggregated particle diameter is small to some extent. However, when the primary particles become several nm to several tens of nm, it becomes easy to aggregate and it becomes difficult to disperse this more than necessary, so there is a preferable range for the aggregated particle diameter. That is, for a preferable range of the aggregated particle diameter, the peak of light scattering intensity by a laser Doppler type particle size distribution measuring instrument using the above-described measurement method is preferably 4 nm or more and 2000 nm or less, more preferably 7 nm or more and 1000 nm or less, and more preferably 10 nm. More preferably, it is 500 nm or less.

  The coating material in the present invention has a very large feature of necking of the particle group A, but due to the necking, the aggregated particles may be larger than the primary particles and may be 1 μm or more. In such a case, if the particle group A is too much, the particle group A tends to settle when the coating material is an aqueous or low-viscosity organic solvent. Even if the particle group settles, it is easily dispersed when the coating material is shaken, so there is no problem in coating, but handling is troublesome if the sedimentation rate is too high. In addition, it is difficult to obtain sufficient film strength only by the particle group A that supports the structure, and in order to fill the voids of the particle group A distributed in the film with the particle group B to some extent. The amount of particles B is required. For this reason, in the particle group A, X / Y is preferably 0.2 or less, where X is the mass of the particle group A in the coating material and Y is the dry mass of the particle group B. At this time, the dry mass is defined as the mass of the solid remaining when the sol containing the particle group B is dried at 120 ° C. for 24 hours. Further, in order to exhibit the properties of improving coating properties, film strength, and creation of a film having high photocatalytic activity by the particle group A, the ratio X / Y of the particle group A to the particle group B in the coating material is 0. .01 or more is desirable. More preferably, X / Y is 0.1 or more and 0.18 or less.

  When the mass X of the particle group A, the dry mass Y of the particle group B, and the mass Z of the entire coating material, the solid content concentration (X + Y) / Z is preferably 0.005 or more and 0.1 or less, this ratio (X + Y ) / Z is less than 0.005, a sufficient amount of photocatalyst particles cannot be left on the substrate after film formation, and it may be difficult to exhibit sufficient photocatalytic performance. Further, the coating material of the present invention is excellent in coating property even at a high concentration as compared with conventional products, but when the solid content concentration is a value exceeding 0.25, it becomes thick at the time of film formation. Stress is generated due to the difference in drying speed between the outermost surface and the substrate-side contact surface, and the film is likely to crack, and it is difficult to maintain sufficient film strength. More preferably, (X + Y) / Z is 0.01 or more and 0.15 or less.

  In the coating material according to a preferred embodiment of the present invention, the particle group A and the particle group are such that X / Y satisfies 0.01 or more and 0.2 or less and (X + Y) / Z satisfies 0.005 or more and 0.1 or less. If B is present, the effects of the present invention can be obtained even if a metal oxide particle group C having a necking structure in which an intermediate number of m particles and 0.2 m particles are connected is additionally present. However, it may be preferable that the particle group C is present, but it is not necessary, and when the mass P of the particle group C is P / X is preferably 1.5 or less, and more preferably 1 or less. If the amount of the particle group C is too large, the aggregate particle diameter of the combined particle groups A, B, and C becomes large, and it may be difficult to obtain a uniform film. Moreover, the same trouble as when a large amount of the particle group A is blended may occur.

In the present invention, if an inorganic binder is used, it is possible to prepare a film having good solvent resistance and high temperature resistance. Examples of the inorganic binder include Zr compounds, Si compounds, Ti compounds, and Al compounds. Specifically, zirconium oxychloride, zirconium hydroxychloride, zirconium nitrate, zirconium sulfate, zirconium acetate, zirconium carbonate ammonium, zirconium propionate and other zirconium compounds, alkoxysilanes, partial hydrolysis products of alkoxysilanes with mineral acids, silicates And the like, and metal alkoxides of aluminum, titanium and zirconium, and partial hydrolysis products of those mineral acids. In addition, an alkoxide of a plurality of metal species selected from alkoxides of aluminum, silicon, titanium, and zirconium may be combined and hydrolyzed. Of these, zirconium compounds are desirable. The film strength may be further improved by blending artificial glass fiber, rock wool, slag wool or the like. The average diameter of these ceramic fibers is desirably 0.5 μm or more and 10 μm or less, and more preferably 2 μm or more and 6 μm or less. Moreover, it is preferable that the diameter of a fiber is 1/11 or more and 1/1 or less with respect to the film thickness after film-forming, More preferably, it is 1/4 or more and 1/2 or less. These fibers lead to improvement of the film strength when the amount is 5% by mass or more with respect to the metal oxide particles which are the main components for imparting a function to the film. When the amount exceeds 100% by mass, the film function is deteriorated. However, since the size of the metal oxide particles is remarkably large, the film may become sparse and the strength may be reduced. Therefore, the content is preferably 100% by mass or less. More preferably, it is 15 mass% or more and 50 mass% or less.
Further, dispersed silica (colloidal silica) and dispersed alumina (alumina sol) may be included in the liquid. These particles are particularly preferably ultrafine particles of 8 nm or more and 50 nm or less, and more preferably 9 nm or more and 30 nm or less. Further, these sols having a pH of 5 or less are preferable because aggregation can be prevented when the metal oxide fine particles having a photocatalytic function are titanium oxide. Colloidal silica, alumina sol and other supplementary metal oxide fine particles added to the metal oxide particles, which are the main components that give the film a function of 5% by mass or more, lead to an improvement in film strength, resulting in 200 masses. If the amount exceeds 50%, the membrane function may be lowered, and therefore it is preferably 200% by mass or less. More preferably, it is preferably 10% by mass or more and 90% by mass or less.
Alkyl silicate, magnesium alkoxide, aluminum alkoxide, titanium alkoxide, aluminum phosphate, and magnesium phosphate are heated against ceramic fibers, colloidal silica, or metal oxide particles that are supplementarily added such as alumina sol. The polymer is partially polymerized to produce a metal oxide having a cross-linked structure, and this polymerization is interrupted by lowering the temperature or adding a reagent, and fine particles with high film forming properties such as ceramic fibers, colloidal silica, and alumina sol A composite binder can be prepared and blended into the coating material. Moreover, you may fulfill | perform a state mechanism by acquiring ladder silicone separately and adding it. The ladder silicone at this time may be close to an oligomer having a molecular weight of about 1000, or may have a molecular weight of tens of thousands.
At this time, since an organic compound that does not dissolve in water may be used, an organic solvent such as methanol, ethanol, and alcohol typified by isopropyl alcohol is used as the solvent. Furthermore, in order to stop the condensation and store the liquid, acetic acid, acetylacetone, or a compound having an isocyanate structure may be blended.
When proceeding polymerization by heating alkylsilicates exemplified by tetramethylorthosilicate or tetraethylorthosilicate alone or in the presence of ceramic fiber or metal alkoxide, the pH should be maintained acidic with mineral acid. Is preferred. At this time, the reaction is stable when the pH is 1 or more and 3 or less. However, when the acidity is too strong, corrosion becomes a problem when applied using the blended coating material, so the reaction is 2 or more and 3 or less. It is preferable. Moreover, it is preferable to polymerize alkyl silicate at a concentration of 1% by mass or more and 10% by mass or less in terms of silica. When the polymerization is performed at a concentration of less than 1% by mass, the metal oxide as the main component is excessively diluted when blended as a binder, and when the reaction is performed at 10% by mass or more, it is difficult to control the polymerization. It is. More preferably, it is 2 mass% or more and 6 mass% or less.
The polymerization temperature is preferably high from the viewpoint of production efficiency. However, when it is desired to keep the molecular weight small and to keep the binder liquid viscosity low, the polymerization temperature should be at a relatively low temperature of 30 ° C. or more and less than 50 ° C. It is preferable to proceed. At this time, it is desirable to use a gel permeation chromatograph (GPC) having a molecular weight of 1000 or more and 2000 or less in terms of PEG when measured using mobile phase tetrahydrofuran.
The reaction temperature and reaction time are in a trade-off relationship. For example, when the reaction is carried out at 40 ° C., it is preferable to stop the reaction time from 1 hour to 2 hours and to cool and stop the reaction. At this time, the kinematic viscosity of the liquid is 1.0 cSt or more and 2.0 cSt or less. Conversely, when it is desired to increase the viscosity of the coating material and create a thick film using the binder, the kinematic viscosity is increased to 1 by increasing the temperature or extending the reaction time as necessary. .2 cSt or more is preferable. In addition, the sample whose viscosity is increased in this manner has an advantage that it becomes stronger against stress compared to a low molecular weight sample due to the increased degree of polymerization. However, if it exceeds 30 cSt, the film tends to be non-uniform and is preferably 30 cSt or less.
It is also possible to improve the mutual characteristics of these binders as a mixture regardless of whether they are organic or inorganic.

In the present invention, when an organic binder is used, it is possible to create a film having relatively good film flexibility. Polyvinyl alcohol, melamine resin, celluloid, chitin, starch sheet, polyacrylamide, acrylamide, poly N-vinylacetamide, N-vinylacetamide-sodium acrylate copolymer, N-vinylacetamide-acrylamide copolymer, polyacrylamide, Acrylamide-sodium acrylate copolymer, poly N-vinylformamide, polytetrafluoroethylene, tetrafluoroethylene-polyfluorinated propylene copolymer, tetrafluoroethylene-polyfluoroalkyl vinyl ether copolymer, polyvinyl fluoride, polyvinylidene fluoride , Styrene-butadiene copolymer, polyvinylpyridine, vinylpyridine-methyl methacrylate copolymer, polyvinylpyrrolidone, polyethylene oxide, urea Resins, one or mixtures thereof of a polymer compound selected from acrylic silicone resin. Among these, poly N-vinylacetamide, polyacrylamide, N-vinylacetamide-sodium acrylate copolymer, acrylamide-sodium acrylate copolymer, polytetrafluoroethylene, urethane resin, and acrylic silicon resin are weather resistant. From the aspect, it is preferable. It is also possible to improve the mutual properties by using these binders as a mixture regardless of whether they are organic or inorganic.
One of the excellent combinations of organic and inorganic binders is a combination of a fluororesin and the aforementioned inorganic binder. This combination has at least three aspects, complements each other's disadvantages of inorganic binders and organic binders, and has synergistic properties, so it is extremely effective when used as a coating material for photocatalysts. .
First, as is conventionally known, fluororesins have high weather resistance and characteristics that can withstand the strong oxidizing power of titanium oxide. Other organic binders are blended as a mixture with an inorganic compound and titanium oxide. When this is used as a coating film, the entire coating film may turn yellow or choke depending on the environment due to its oxidative properties. It can happen. On the other hand, when the fluorine resin is added to the inorganic binder and blended, the weather resistance of the entire film is not impaired.
Furthermore, the second function is to relieve the stress generated in the film due to various factors by utilizing the characteristics as the resin. In general, when a film having a thickness of 1.0 μm or more is to be formed by a single coating rather than a recoating using a coating agent, the composition in the film thickness direction is not improved during the drying process of the film, that is, the solvent drying. In many cases, cracks or the like due to stress that occurs from the uniformity occurs, and the film strength is likely to decrease. Although this strength reduction occurs even when applied on a flat plate, this phenomenon is remarkable when the substrate is curved or uneven. On the other hand, as described above, the addition of a fluorine resin makes it possible to relieve stress in the film. Therefore, the coating material having this inorganic substance + fluorine resin combination is particularly effective at the time of forming a thick film. It is.
Thirdly, it is possible to have strong wear resistance at the same time while having elasticity. If the strength is increased only by the resin, the surface layer may be worn out. However, the film of the present invention contains a particle group H that is metal oxide particles and an inorganic binder in a preferable ratio. Therefore, it has moderate hardness.
The fluororesin used synergistically with the inorganic binder in the present invention is not particularly limited, but polytetrafluoroethylene, tetrafluoroethylene / perfluoropropylene copolymer, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer Polymers, tetrafluoroethylene / ethylene copolymers, polyvinylidene fluoride, polychlorotrifluoroethylene, and the like can be used. Of these, polytetrafluoroethylene is preferred from the viewpoint of economy because it is easy to obtain a variety of particle sizes. In addition, the existence form of the fluorine-based resin is not particularly limited, such as a powder form or a slurry form, but it is highly dispersed with an anionic or nonionic surfactant. Use of a dispersion is preferable because it is easy to process as a coating agent. The coating material in the present invention can maintain strength even when the film thickness is increased, but a film having a film thickness of 1 μm or less may be formed. For this reason, it is preferable that the particle diameter of the fluororesin to be added is such that d50 is 2 μm or less when measured using the previous laser scattering method. More preferably, it is 1 μm or less so as to fit in the film, and further preferably 0.4 μm or less so as to enter the gap of the titanium oxide necking particles.
The coating material containing the fluororesin and the titanium oxide dispersion in the present invention is a coating material characterized by high dispersibility and high photocatalytic activity. Below, the amount of sedimentation components and the amount of solid content are demonstrated.
The solid content in the coating material means that 100 g of the coating material is weighed in a Pyrex (registered trademark) beaker, placed in a constant temperature dryer at 120 ° C. for 24 hours or more, and the remaining solid content is weighed. Measured. The solid content concentration of the coating material can also be calculated from the solid content mass.
A fluororesin can be formed at a relatively low temperature of 200 ° C., although it is possible to reach a melting point for the first time by heating at 300 ° C. or higher, for example, in the case of polytetrafluoroethylene at 330 ° C. or higher. However, sufficient film strength can be obtained. When the curing temperature is 200 ° C. or lower, film formation is possible without impairing the properties of tempered glass, and it can be applied to general-purpose resins with moderate heat resistance such as polyethylene terephthalate and polyethylene naphthalate. Therefore, the substrate selection range is remarkably increased. The mechanism by which the film cures even below the melting point of the fluororesin is unknown, but as a possible cause, (i) gas phase method used in the present invention, or liquid phase synthesized titanium oxide was used as the main component of the coating material In some cases, the surface chemically and physically interacts with the surface of the fluororesin, leading to the achievement of film strength. (ii) Heating is performed at the time of film formation. At this time, the solvent contained in the coating material evaporates, and the volume becomes one-fifth after drying compared to immediately after coating. At this time, since the particle group B is an ultrafine particle of about 10 nm, a strong cohesive force due to the liquid bridge effect works, and this force causes an effect similar to that of press-bonding a fluororesin, thereby achieving strength. . There are two. In order to achieve the effect of the film curing described above, it is preferable that the fluororesin is fine particles of 2 μm or less, more preferably 0.4 μm or less, as described above. However, it is difficult to obtain those having a thickness of 0.01 μm or less. Furthermore, it is preferable that the fluororesin be present in the liquid in a state of good dispersibility. At this time, it may be necessary to disperse the fluororesin contained in the coating material by using a dispersant, but the dispersant used at this time may be used regardless of anionic or nonionic. Although it is possible, it is particularly preferable to use a nonionic system. This is because the nonionic resin can disperse the fine particles of the fluororesin even in a relatively reduced amount, and the nonionic resin can be volatilized at about 200 degrees. This is because it exists. If the surfactant remains in the film, there is a concern that the film strength may be lowered or the photocatalytic performance may be adversely affected by the surface active action. In the present invention, nonionic surfactants that can be used to disperse the fluororesin are sucrose fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, ethylene oxide-propylene oxide copolymer, polyoxy Ethylene fatty acid ester, fatty acid alkanolamide, polyoxyethylene alkyl ether, alkyl glycoside, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, alkyl glycoside, polyoxyethylene fatty acid ester and the like can be used. These are preferably added in an amount of 0.5% or more and 10% or less based on the weight of the fluorine-containing resin to be blended. These surfactants may be blended directly into the coating material. However, it is better to disperse the fluororesin in the liquid in which the surfactant is first dissolved and then blend this into the coating material. It is possible to improve the overall dispersibility.
The intention of the present invention is to have both sufficient film strength and photocatalytic function. For this purpose, it is desirable that the solid content in the coating material is 10% by mass or more. When it is desired to exhibit the above, an excessive binder is not preferable, so that 50% by mass or more of the solid content is preferably titanium oxide. More preferably, it is 60 mass% or more, More preferably, it is 70 mass% or more. When the components blended to give the film a photocatalytic function are blended at a high ratio as described above and a thick film of 1 μm or more is to be formed, it is difficult to maintain the film strength with the conventional technology. However, it is possible to achieve further improvement in the film strength by using the particle group A, the particle group B, the inorganic binder, and the fluororesin which are necked according to the present invention. Among the binders blended in the coating material, when the inorganic type is Iw [g] in terms of 120 ° C. dry solids and the fluororesin is Fw [g] in terms of 120 ° C. dry solids, When Iw / Fw is 0.05 or more and 20.0 or less, a coating film in which the characteristics of both inorganic and fluororesin are synergized can be obtained. More preferably, it is 0.2 or more and 3 or less, and further preferably 0.5 or more and 1 or less.

  In the present invention, the ratio of the binder contained in the coating material is one of the features that the amount of the binder can be reduced as compared with the conventional coating material as described above. However, when it is desired to give greater strength and flexibility to the film, blending of the above inorganic or organic binder components is not hindered. In this case, it is desirable that the total solid content mass Z is 0.01 or more and 0.5 or less. Further, if the strength can be maintained, the amount of the binder component is desirably a smaller ratio for exhibiting the photocatalytic performance, and is 0.01 or more and 0.4 or less, and further 0.1 or more and 0. .35 or less is desirable.

  Furthermore, a surfactant can be appropriately added to the coating material from the viewpoint of coatability. Surfactants include condensed phosphate, lignin sulfonate, carboxymethyl cellulose, naphthalene sulfonate formalin condensate, polyacrylate, acrylic acid-maleate copolymer, olefin-maleate copolymer, alkyl diphenyl ether disulfone. Acid salts, dodecylbenzenesulfonic acid and its salts, nonionic surfactants and the like are used. A polyacrylic acid surfactant is preferred.

  As for the quantity of surfactant used for a coating material, it is desirable that surfactant mass is 5 ppm or more and 2000 ppm or less with respect to the total mass of a coating material. If the amount of the surfactant is too small, a trace amount of dirt may remain on the base material, or if the surface energy of the base material is very small, it may cause liquid repelling or uneven coating. On the other hand, if the amount of the surfactant is too large, not only the binding between particles is inhibited and the film strength is lowered, but also adsorbed on the surface of the photocatalyst particles, which may inhibit the expression of the catalyst performance. For this reason, it is more desirably 10 ppm or more and 500 ppm or less.

  The solvent used for the coating material is a volatile liquid that can promote mixing of the metal oxide fine particles and the binder by dispersing the particle groups A and B and dispersing, dissolving, or swelling the binder. If it is, it can be used without limitation. Specifically, a volatile liquid having a hydroxyl group, a carboxyl group, a ketone group, an aldehyde group, an amino group, or an amide group in its skeleton is preferable. For example, water, methanol, ethanol, propanol, butanol, methyl cellosolve, ethylene glycol, acetic acid, acetylacetone, turpentine oil, methylpyrrolidone alone or a mixture thereof can be used. Among these, when an aqueous solution containing 40% by mass or more of ethanol is used as a solvent, the wettability with various substrates is good, and when 50% by mass or more is further contained, the drying rate after coating can be increased, and productivity is improved. high. In addition, when a liquid containing 50% by weight or more of butanol in a volatile solvent containing alcohols or acetonitrile compatible with butanol is used as a solvent for the photocatalyst coating material, it has a high viscosity at room temperature and a variety of base materials. It has high affinity and can be formed by vaporizing a solvent at around 100 ° C. and used as a coating material for forming a film on a target substrate by using a method such as a squeegee method or a screen printing method. It is possible and desirable.

  In the present invention, since the particle group A and the particle group B having good dispersibility with respect to the solvent are used, there is no difficulty in preparing and blending the coating material. However, if necessary, mixing using a ball mill, bead mill, paint shaker or the like is not hindered. However, in order to exhibit the various effects exhibited in the present invention, it is desirable to adopt a mixing method in which the necking structure of the particle group A is not extremely destroyed. Specifically, it is desirable to use a rotation / revolution kneader or the like that does not damage the necking structure or make the crystal surface amorphous by impacting the particles. Also, among the ultrasonic dispersers, a convection type in which dispersion is promoted by flowing the liquid to be dispersed in the vicinity of the oscillator, and a throw-in type in which the oscillator is placed in a container containing the liquid to be dispersed and dispersed. A disperser may be used. At this time, dispersion may be performed at any frequency of 28 kHz, 40 kHz, and 100 kHz, and dispersion may be performed using a disperser in which these waves are mixed or alternately oscillated.

When forming a film using a coating material, apply it by spray coating, spin coating, doctor blade, flow coating, roll coating, etc., remove the solvent by drying, and further heat if the binder is thermosetting It is also possible to use this method. The photocatalyst film obtained by spin coating or flow coating is dense, excellent in transparency, and does not impair the design of the substrate as a clear coat. In contrast, spray coating, doctor blades, and roll coating can be used industrially. Among them, spray coating can be continuously dried while coating, and film thickness can be controlled by applying time, This is preferable because it can be adjusted by the spray amount per hour.
When the liquid of the present invention is applied, a characteristic application technique as described below can be used to provide a stable strength even when the film thickness is increased. First, a liquid is prepared so that the concentration of metal oxide fine particles in the coating material is a medium concentration such that the concentration is 5% by mass or more and 25% by mass or less (in this case, the metal oxide particles are necking particles, ie, particles It is desirable to include group A), and this is applied onto a substrate by flow coating or dip coating, and dried at about 150 ° C.
After the thick film is applied, the coating material including the particle group B and the binder, the solid content concentration of which is 1/2 or less of the first coating material, is applied and dried. Also good. At this time, the solid content concentration of the overcoating material is more preferably 0.5% by mass or more and 5% by mass or less.
In the first coating material, the particle size distribution measured with a laser Doppler particle size distribution meter is two, whereas in the overcoating coating material, there is one. The number of peaks in the particle size distribution of the material used for the first coating is preferably larger than the number of peaks in the particle size distribution of the overcoating material.
As a result, it was possible to increase the adhesion amount of titanium oxide particles per unit area and at the same time to further improve the film strength as compared with the case where one thick film was applied. This is presumably because the particle group B having good dispersibility penetrates into the voids generated when the thick film is formed, and the voids are filled.

  Drying and curing are desirably performed at 75 ° C. or more and 500 ° C. or less. By increasing the drying temperature, the organic solvent component remaining in the film can be volatilized more reliably, but when heated to 500 ° C. or higher, the metal oxide particles begin to weld together, In some cases, the characteristics of the film as a porous material cannot be maintained. Heating can be performed using a hot plate, electric furnace, dryer, dryer, etc., but curing can be performed using a dryer or hot air convection dryer that can provide a sufficient amount of heat during film formation at a constant temperature. It is desirable to do. When hot air drying is performed, the solvent can be sufficiently volatilized at a temperature below the boiling point of the solvent to form a film, which is a very useful technique when the heat resistance of the substrate is low. The drying time increases until the temperature of the base material increases until the solvent volatilizes, and until the solvent surely volatilizes. Necessary until finished. In general, for both inorganic and organic binders, it is sufficient to maintain the curing temperature for about 15 minutes after the temperature rises. Excessive heating may lead to deterioration of the substrate and increase in energy costs.

When the film thickness after drying and curing is less than 50 nm, the performance of antifouling, deodorizing, antibacterial and the like is not sufficiently exhibited, so that the film formation is desirably performed at 50 nm or more. If the film thickness exceeds 30000 nm, it is difficult to obtain sufficient film strength as described above, which is not desirable. In order for the necking of the particle group A to effectively work as a structural support or a framework in the coating material, the film thickness is desirably 5 times or less the aggregate particle diameter of the particle group A. Further, the aggregated particle diameter of the particle group A may be larger than the average film thickness, but when the average film thickness is smaller than 1/3 times the aggregated particle diameter of the particle group A, the particle group relative to the film. Since A is too large and the film tends to fall off, the average film thickness is desirably at least 1/3 times the aggregated particle diameter of the particle group A.
Since a photocatalyst can decompose organic substances into water and carbon dioxide, it is generally more resistant to organic substances than conventional catalysts in an environment exposed to light. However, inorganic contamination, that is, contamination with metals, nitrogen oxides, and sulfur oxides, remain oxidized even when oxidized on the surface of the photocatalyst, and may adversely affect the photocatalytic performance. In particular, nitrogen oxides and sulfur oxides are abundant as inorganic components present in the air, and NO ₃ ^- or SO ₄ ^2- is stably adsorbed on titanium oxide, and further, sulfur oxides do not volatilize at all. Accumulate over time on the titanium surface.
It becomes difficult for the poisoned titanium oxide to adsorb the target decomposition target. Most of the decomposition of the organic compound occurs after the substrate is adsorbed to titanium oxide, and when the adsorption site is blocked with a poisonous substance, the performance is significantly reduced. The coating material of the present invention is 1% by mass in titanium oxide concentration, applied to a 7.5 cm square (56.25 cm ² ) glass plate, dried, and adjusted to 20 ° C. and 50% humidity. The glass plate was put inside, and a fluorescent lamp “Mellow White” manufactured by Toshiba Lighting & Technology Co., Ltd. was used from the outside to adjust the position to 10000 lux at the sample position, and a 12 hour contamination test was performed. Samples that were not contaminated, samples that were contaminated with NO, and samples that were contaminated with SO ₂ were placed in 500 ml of gas adjusted to 20 ° C., 50% humidity, and 500 ppm acetaldehyde, respectively. Using “white”, irradiation was performed so that the glass sample position was 10,000 lux, and the time-dependent change in the acetaldehyde gas concentration was observed using gas chromatography.

As shown in Table 1, only the sample contaminated with SO ₂ showed a significant performance degradation. Moreover, when these samples were washed with water, it turned out that the acetaldehyde reduction curve equivalent to the sample which did not contaminate was drawn. When the water used for this sample washing was measured by ion chromatography, the amount of SO ₄ ^2- elution reached 1% by mass with respect to the sample titanium oxide, and contamination was occurring at this concentration even when estimated to a small extent. all right. From these results, it was confirmed that the performance of the thin film deteriorates due to contamination with sulfur oxide. Also, in SO ₂ contained in the air, it is presumed that sulfur oxide poisoning accumulates on the surface of titanium oxide in the form of SO ₄ ²⁻ over time. Even in a real environment, a photocatalyst is applied to a sample, left under irradiation with strong light of about 15000 lux, and left in the open atmosphere for about 2 months. When acetaldehyde decomposition is subsequently confirmed, a decrease in deodorization performance is observed. . When this sample was analyzed in the depth direction by XPS, it was confirmed that the entire film was contaminated with sulfur compounds at a uniform concentration. When the dissolution test was conducted, SO ₄ ^2- It was confirmed that it was contaminated.
In addition, the effect is unclear compared to sulfur compounds, but if the substrate contains relatively light metal ions or there are pollutants such as sulfur compounds, not only from the atmosphere. Contamination also occurs from the substrate side.
There are three main methods for dealing with pollution. First, increase the amount of film deposited per unit area, lower the concentration of contamination, second, capture contaminants (undercoat / chemical / physical), and third, remove contaminants outside the membrane It is to put out (catalyst, water washing, platinum).
Regarding the first countermeasure, increasing the amount of adhesion tends to be recognized as an easy task, but it is actually difficult. Because photocatalytic coatings have strong oxidizing power under light irradiation, when coatings with several years of weather resistance are required, create coatings with components that will not be destroyed even when subjected to oxidation centering on inorganic substances. There is a need. At this time, if the film is made thicker due to the hardness derived from the inorganic component, stress is generated due to non-uniform concentration at the time of drying, cracking or the like may occur, resulting in a decrease in strength. Further, when the substrate is flexible, the film made of this general inorganic component is liable to decrease in film strength even with a slight strain. The film including the particle group A and the particle group B of the present invention is easily maintained in strength even when the film thickness is increased as compared with a coating material having a normal particle size distribution. Further, as described above, artificial glass fiber, rock wool, slag wool or the like may be arranged like a reinforcing bar for concrete. Alternatively, a minimum amount of a sample obtained by complexing with alkyl silicates alone, ceramic fiber or metal alkoxide, and partially polymerizing by the above-described method may be used as a binder. At this time, even if a sample in which an increase in the viscosity can be confirmed is used, an increase in the adhesion amount of the film may be expected. Further, a coating material combined with a fluorine resin may be added at a minimum.
From the viewpoint of dilution of pollutants, metal fine particles having no photocatalytic function may be mixed to some extent with the photocatalyst particles. Specifically, a method of distributing and dispersing the concentration of contamination due to sulfur oxides of titanium oxide, etc., using silica, alumina, etc. having high hydrophilicity, fine particles and a large specific surface area per weight. You can take it. The sample to be added preferably has a center particle size of 5 nm or more and 3 μm or less, and preferably 8 nm or more and 1 μm in view of film formability and cost. In particular, silica fine particles having a specific surface area per gram exceeding 1000 m ² are available, which is preferable for dispersing the concentration of contaminants. Among these, considering cost, adsorption, and dispersion, it is preferably 300 m ² / g or more and 1000 m ² / g or less. In addition, colloidal silica and alumina sol are superior in film formability compared to titanium oxide fine particles, so it is possible to increase the amount of film deposited per unit area and reduce the concentration of contaminants in the film. is there.
In order to achieve a thick film and a high film strength by the coating method, a coating having a solid content of 0.5% by mass or more and 2% by mass or less is further applied after the thick film is first applied as described above. If the material is coated and dried as a top coat, a higher strength film can be produced.
As a second countermeasure against contamination, there is a method in which a contaminant is adsorbed or immobilized on an additive to prevent poisoning on the surface of the photocatalyst particles.
In order to capture contaminants and prevent poisoning on the surface of the photocatalyst by physical adsorption, it is possible to use activated alumina, A-type, Y-type zeolite, activated carbon or the like having high adsorption ability. Among these, activated alumina may be used particularly from the viewpoint of color tone, availability of fine particles, adsorption capacity of sulfur oxides, and the like. These physical adsorbents are preferably blended in an amount of 10% by mass or more and 200% or less with respect to the photocatalyst fine particles in order to increase the poisoning resistance of the film. When emphasizing the initial photocatalytic performance, the concentration of the physical adsorbent with respect to the photocatalyst fine particles is preferably 5% by mass or more and 150% by mass or more. More preferably, it is 20 mass% or more and 50 mass% or less. These physical adsorbents are preferably crushed using a ball mill, a bead mill, a rocking mill, a paint shaker, or the like as necessary to obtain a particle size of 5 nm or more and 5 μm or less because the film formability is improved. As a method for immobilizing the pollutant, there is a method of deionizing as a chemical substance. This is hereinafter referred to as a chemical scavenger. For example, transition metal oxides, copper oxide, iron oxide, manganese oxide, and zinc oxide fine particles have a strong action of capturing sulfur oxides. Also, alkaline earth metal compounds, especially chlorides, such as magnesium chloride anhydride, magnesium chloride hexahydrate, calcium chloride anhydride, calcium chloride dihydrate, strontium chloride, strontium chloride hexahydrate , Barium chloride anhydrate, and barium chloride dihydrate become hardly soluble sulfates in the presence of sulfate ions, and it is possible to prevent the sulfate ions from being adsorbed on the surface of the photocatalyst particles. In addition, when the coating material is alkaline, the alkaline earth metal salt to be added may be a carbonate or hydrogen carbonate of the exemplified metal. These chemical scavengers are water-soluble in the state of chloride, and a certain amount dissolves in some organic solvents such as alcohol. Therefore, they are added to the photocatalyst coating material and mixed with the photocatalyst particles. Application and film formation at a time are possible. Alternatively, the surface of the photocatalyst particles can be formed by applying a photocatalyst coating material that does not contain an additive, forming a film, then overcoating with water or an organic solvent in which an alkaline earth metal compound is dissolved or dispersed, and forming a film. It is possible to add an additive to. If the photocatalyst coating must be baked and cured at a high temperature of 100 ° C. or higher, the photocatalyst particles and the alkaline earth metal that are highly reactive nano-sized particles can be obtained if the photocatalyst coating is heated to a high temperature in a state containing an alkaline earth metal. Ions may react and performance may be reduced. For this reason, when high temperature is required at the time of hardening of a film | membrane, after apply | coating the photocatalyst coating material which does not contain a chemical capture agent, the method of apply | coating a chemical capture agent as an overcoat is effective.
The amount of these physical adsorbent and chemical scavenger added depends on the environment in which the photocatalyst is used and the period during which the effect must be maintained. In an environment where the photocatalyst coating film is washed away once or more a month by rainwater or the like, contamination of the poisoned inorganic substance is washed away, so that these chemical scavengers and physical adsorbents are satisfied in a small amount. Conversely, it is a photocatalyst that is deployed near an environment that is highly polluted with sulfur oxides, such as roads with high traffic volumes, furnaces that burn sulfur-rich gases, and rainwater. When washing with moisture cannot be expected, larger amounts of physical adsorbent and chemical scavenger are required. In addition, when the photocatalyst is applied to a place where it is exposed to direct sunlight, in the vicinity of the illumination, or in the illumination itself, the amount of light is large, so the oxidation rate of the contaminated gas on the surface of the photocatalyst increases, and contamination by sulfur oxide etc. Accumulation becomes significant. For this reason, more additives are required. In addition, in order to maintain the photocatalytic effect for a long period of time in an environment where contamination is likely to accumulate, a larger amount of physical adsorbent and chemical scavenger is required. When the copper oxide, iron oxide, manganese oxide, zinc oxide fine particles or alkaline earth metal compound blended in the coating material is 0.01% by mass or more with respect to the photocatalyst particles in terms of metal, such an effect is obtained. It is recognized, and if it is added in an amount exceeding 200%, the photocatalytic performance may be impaired. In order to sufficiently exhibit the initial performance, the content is preferably 1% by mass or more and 50% by mass or less with respect to the photocatalyst particles. The above value depends on the life of the required photocatalytic performance and the usage environment, but an ultraviolet light meter that integrates and quantifies the amount of ultraviolet light having a wavelength of 310 nm to 390 nm and emits light of 0.1 mW / cm 2 or more for 12 hours. / Day irradiation, SOx concentration is 50 ppb, photocatalyst life of 1 year or more, it is preferably 5% by mass or more and 20% by mass or less. The alkaline earth metal may be used alone when blended in the photocatalyst coating material, or two or more compounds may be mixed and dissolved or dispersed.
When removing contaminants using a physical adsorbent and a chemical scavenger, the component concentration need not be uniform with respect to the composition of the membrane. It is possible to give a gradient to the concentration of components that trap contaminants in the film thickness direction. It may be overcoated or localized as an undercoat. For example, when it is known that the contamination originates from the outside, a photocatalyst coating film may be first prepared as described above, and a physical adsorbent or a chemical scavenger may be overcoated. Conversely, when it is known that the pollutant is derived from the base material, the physical adsorbent and chemical trapping material are processed as an undercoat material, coated and formed, and then a photocatalytic film is prepared. Also good. When physical adsorbents and chemical trapping materials also have a slight adverse effect on the photocatalytic performance, it is preferable that the photocatalytic component and these trapping materials are unevenly distributed in the film because the initial photocatalytic performance is higher. is there.
The third countermeasure against pollutants is to discharge pollutants outside the membrane. The easiest method is washing with water. When the pollutant has accumulated, the whole substrate is washed with water to elute the inorganic poisoning substance. However, if the part to which the photocatalyst is applied becomes unusable due to water, such as an electronic device, or is huge, water washing cannot be applied everywhere. For this reason, it is necessary to use a technique for removing contaminants from the photocatalytic film even by a technique other than washing with water.
Photocatalytic semiconductors are often used mainly for oxidative decomposition, but at the same time have a photoreduction effect. Although very slow, it is known that water can be reduced to hydrogen gas with a promoter. In this examination, it added and examined focusing on platinum metal, nickel metal, nickel oxide, cobalt oxide, and molybdenum oxide with respect to the photocatalyst particle. When glass plate samples coated with this transition metal or its oxide coating material were forcibly contaminated with sulfur oxides, performance degradation was prevented compared to those not added. I was able to. The addition amount of these transition element metals or oxides thereof is preferably 0.1% by mass or more and 200% by mass or less with respect to the photocatalyst fine particles. Some oxides are colored, and when design properties are required, it is necessary to adjust the addition amount to 0.1% by mass or more and 1% by mass or less with respect to the photocatalyst particles. In some cases, the pH of the solvent may be changed from weakly acidic to alkaline using ammonia, phosphate, carbonate, or the like, since the solvent used as the coating material and some of the material dissolves depending on the pH. In order to develop the effect, platinum metal and its compound are preferable among the transition metals, and it is preferable to use nickel oxide, cobalt oxide, and molybdenum oxide in combination with these metals. The compounding ratio of platinum metal and other transition metal oxide is preferably 20% by mass to 10,000% by mass with respect to platinum metal. In view of the fact that platinum metal is expensive, the transition metal oxide is preferably 100% by mass or more and 900% by mass or less with respect to platinum metal in order to exert the effect while making the platinum metal as small as possible. Is preferably 300% by mass or more and 600% by mass or less. As described above, the sum of platinum metal and transition metal oxide is preferably 0.1% by mass or more and less than 200% by mass, more preferably 0.5% by mass or more and 1% by mass or less with respect to the photocatalyst fine particles. However, it is preferably 5% by mass or more and 100% by mass or less in an environment where water is not washed for a long period of 1 year or longer and the degree of contamination is high. The added platinum, its compound and transition metal oxide are preferably fine particles of 10 μm or less from the viewpoint of dispersibility in the coating material. More preferably, it is 5 μm or less.

  The photocatalyst film formed from the coating material in a preferred embodiment of the present invention has functions such as deodorization, antifouling and antibacterial functions. In general, the amount of substances that have to be decomposed is higher for deodorizing than antifouling and antibacterial, requiring a large reaction rate and catalyst amount, and maintaining a high strength compared to conventional products. The present coating material capable of forming a film is very desirable as a coating material imparting a deodorizing function. In addition, the photocatalyst film obtained by the coating material of the present invention has a great feature that it is highly resistant to contamination in the air or from the substrate. The coating material in a preferred embodiment of the present invention can be applied to a substrate such as various materials and molded bodies to form a photocatalytic film on the surface of the substrate. Substrates such as ceramics, glass, metal, plastic, wood, paper, etc. can be used without any limitation. Further, it is preferable that the base material has a filter shape because it can be efficiently used for air purification when the coating material is applied. Further, when the filter is combined with a light source to form a device, and the integral value of the ultraviolet light amount at the filter position from 310 nm to 390 nm is 0.05 mW / cm 2 or more, the contaminant in the photocatalytic film per light irradiation time It is particularly effective to make the photocatalyst film have antifouling performance as in the present invention. The decomposition performance of the volatile organic compound at the time of installing the filter is self-evident, but the higher the amount of light, the higher the amount of ultraviolet light. Usually, the ultraviolet light amount at the filter position is designed to be 0.1 mW / cm 2 or more. That is, the coating material of the present invention is extremely effective for extending the stain resistance and durability of the filter with a photocatalyst. The base material may be a catalyst carrier made of alumina, zirconia or the like, and a titanium oxide thin film catalyst may be supported on the base material and used as a catalyst. Moreover, if a titanium oxide thin film is formed on a glass or plastic cover of a lighting device such as a fluorescent lamp as a base material, the thin film can maintain transparency and has a photocatalytic action so that it does not block light, such as oil smoke. Organic substances can be decomposed, which is effective in preventing dirt on the glass and cover. In addition, if a titanium oxide thin film is formed on architectural glass or wall materials, it becomes possible to prevent contamination as well, so it can be used for window materials and wall materials for high-rise buildings, etc., and cleaning work is not required. It is about to reduce building management costs.

  Examples of articles having such a photocatalytic function include, for example, building materials, lighting fixtures, design window glass, machines, vehicles, glass products, household appliances, agricultural materials, electronic devices, mobile phones, tools, tableware, baths Supplies, pure water production equipment, toilet articles, furniture, clothing, cloth products, textiles, leather products, paper products, resin products, sports goods, futons, containers, glasses, signs, piping, wiring, metal fittings, sanitary materials, automobile supplies, Stationery, patches, hats, bags, shoes, umbrellas, blinds, balloons, piping, wiring, metal fittings, lighting, fluorescent lights, LEDs, traffic lights, street lights, toys, road signs, ornaments, tents, cooler boxes and other outdoor equipment, Mention may be made of artificial flowers, objects, filters, among them filters intended for deodorization.

  It is also applied to environmental purification equipment and devices effective for measures against sick houses, decomposition of organic chlorine compounds such as PCBs and dioxins in water, air and soil, and decomposition of residual agricultural chemicals and environmental hormones in water and soil. it can. In that case, it is possible to use a film formed on an article. Among the above, in particular, when the present invention is applied to a fluorescent lamp, the photocatalyst particles are present in the vicinity of the light source, and a very large amount of energy can be obtained. Furthermore, since fluorescent lamps are prevalent in almost all homes, offices, stores, etc., they can make a great contribution to reducing the concentration of organic and inorganic substances that adversely affect the indoor environment. In addition, when used in a pure water production device, the photocatalyst film formed by the coating material of the present invention has a very strong oxidizing power, and is optimal for decomposing organic impurities contained in trace amounts in water. .

  In addition, as a light source that can effectively develop its photocatalytic property and hydrophilicity, the sun, fluorescent lamp, incandescent lamp, mercury lamp, xenon lamp, halogen lamp, mercury xenon lamp, metal halide lamp, light emitting diode, laser Examples include organic combustion flames. Examples of fluorescent lamps include fluorescent lamps with ultraviolet absorbing films, white fluorescent lamps, daylight white fluorescent lamps, daylight fluorescent lamps, warm white fluorescent lamps, light bulb color fluorescent lamps, and black lights. It is not limited to.

  This coating material can be applied not only to the photocatalyst film but also to the formation of a dielectric film, a photoelectrode film of a dye-sensitized solar cell, a UV shielding film, an anticorrosion film, and a weather resistance imparting film. When the coating material containing the particles having necking of the present invention is used, it is possible to form a titanium-containing perovskite oxide film having high strength and high crystallinity, and having excellent electric characteristics with low leakage current, Thin film dielectrics such as dielectric ceramics, dielectric films, and dielectric coatings required for small capacitors that enable miniaturization of equipment can be formed. Further, since the necking particles have high crystallinity and good electron conduction, have appropriate porosity as an electrode, and have a higher strength, the coating material of the present invention can be used as an industrial oxide as a porous electrode. It is extremely useful for forming an electrode or a reduction electrode, a positive electrode for a small primary or secondary battery, a negative electrode, especially a dye adsorption side electrode of a dye-sensitized solar cell. The coating material according to a preferred embodiment of the present invention is not limited to the above-described use, and the function of the metal oxide in the metal oxide coating film is low because the binder amount is small and the film strength is high. It is possible to form a film that performs functions such as ultraviolet shielding, corrosion prevention, and weather resistance.

Hereinafter, although a metal oxide dispersion is concretely demonstrated in an Example and a comparative example, this invention is not limited to these at all.
(Deodorization test method)
A method for performing a deodorization test of acetaldehyde gas on a glass sample (20 cm × 20 cm) coated with a coating agent is shown below.
Two types of glass samples are prepared, one for light irradiation and one for blank (dark place). A glass sample and air containing 20 vol ppm acetaldehyde gas are used in a 5 L Tedlar (registered trademark) bag (manufactured by GL Sciences). ), And one was irradiated with a daylight white fluorescent lamp (Mellow White (registered trademark) manufactured by Toshiba Lighting & Technology Co., Ltd.) to 10000 lux, and one was kept in a dark place. The concentration of acetaldehyde in the Tedlar (registered trademark) bag after 1 hour was measured with a gas detector tube (Gastech, Inc., 92 L). The rate of gas reduction with respect to the initial concentration of 20 ppm was defined as the value of gas removal rate [%].

(Membrane strength test method A)
About the glass sample (20 cm x 20 cm) which coated the coating material, the film strength test method is shown below.
The glass sample coated with the photocatalyst was fixed on a rubber plate so as not to move, and rubbed by applying a weight of about 5 kg with dry hands.
(Membrane strength test method B)
A pencil scratch test according to JIS-K5400 was performed.

(Liquid phase particle synthesis)
Distilled water (9.1 L) was charged into a reaction vessel equipped with a reflux condenser and heated to 95 ° C. to maintain it. While maintaining the stirring speed at about 200 rpm, a titanium tetrachloride aqueous solution (Ti content 16.5% by mass, specific gravity 1.52, manufactured by Sumitomo Titanium Co., Ltd.) 0.9 L was reacted at a rate of about 10 mL / min. It was dripped at the tank. At this time, care was taken not to lower the temperature of the reaction solution. As a result, the titanium tetrachloride concentration in the reaction phase was 0.5 mol / L (4% by mass in terms of titanium oxide). In the reaction vessel, the reaction solution started to become cloudy immediately after the dropping, but kept at the same temperature, and after the dropping was finished, the temperature was further raised and maintained at a temperature near the boiling point (101 ° C.) for 60 minutes. The obtained sol was washed with pure water using an ultrafiltration membrane (Microza ACP-1050, pore diameter of about 6 nm, manufactured by Asahi Kasei Co., Ltd.) until the conductivity of the washing solution reached 100 μS / cm, and when dried at 120 ° C. It concentrated so that solid content concentration might be 15 mass%. When the method described above was employed and measurement was performed with a laser Doppler particle size distribution meter, it was found that the distribution had a peak at 22 nm as shown in FIG. When the BET specific surface area of the obtained solid was measured using a BET specific surface area meter (Flowsorb 2300 manufactured by Simadzu), it was 150 m ² / g, and the average primary particle diameter calculated from this value based on the formula (2) is It was found to be about 10 nm. Further, this solid content was pulverized in an agate mortar and measured for powder X-ray diffraction. Rigaku-Rint Ultimate + was used as a measuring device. The X-ray source used was CuKα1, the output was 40 kV-40 mA, the divergence slit was 1/2 °, the divergence length limiting slit was 10 mm, the scattering slit was 1/2 °, and the light receiving slit was 0.15 mm. The scanning step was 0.04 °, the counting time was 25 seconds, and the X-ray diffraction pattern was measured under FT conditions. When the obtained X-ray pattern was analyzed using the Rietveld analysis method, it was a brookite crystal-containing titanium oxide powder containing 75% by mass of brookite crystals, 20% by mass of anatase crystals, and 5% by mass of rutile crystals. As a result of measuring the tap density of the dry powder pulverized in an agate mortar using a powder characteristic synthesis device PT-D (made by Hosokawa Micron) based on the method shown in JIS K-5101-20.2, Was 1.2 g / cm ³ . When the true density ρ of titania was 4.0 g / cm ² and calculated based on the equation (1), the number m of necking particles obtained by this liquid phase method was 3.2. Further, when observed with a transmission electron microscope (JEM-200CX manufactured by JEOL), the primary particle diameter was about 10 nm.
(Confirmation of performance degradation due to contamination)
The prepared coating material was applied to a 7.5 cm square glass plate, dried, and placed in 5 L of 50 ppm SO ₂ gas adjusted to 20 ° C. and 50% humidity. ) Using a fluorescent lamp “Mellow White”, the position was adjusted to 10000 lux at the sample position, and a contamination test was conducted for 12 hours.
Place the uncontaminated sample and the above-contaminated sample in 500 ml of gas adjusted to 20 ° C, 50% humidity, and 500 ppm acetaldehyde, respectively, and use "Mellow White" from the outside to place the glass sample. Irradiation was carried out so as to be 10,000 lux, and the reduction rate after 4 hours of the acetaldehyde gas concentration was measured using gas chromatography.

Example 1 :
(1.1) Synthesis of particle group A-1:
Gas containing titanium tetrachloride formed by mixing gaseous titanium tetrachloride 4.7 Nm ³ / hour (N means standard state; the same applies hereinafter) and nitrogen 16 Nm ³ / hour at 1,100 ° C. and air An oxidizing gas obtained by mixing 20 Nm ³ / hour and water vapor 25 Nm ³ / hour is preheated to 1,000 ° C., and is supplied to the reaction tube at a flow rate of 92 m / second and 97 m / second using a coaxial parallel flow nozzle, respectively. Introduced. The inner diameter of the coaxial parallel flow nozzle was 20 mm, and a gas containing titanium tetrachloride was introduced into the inner pipe.

  The inner diameter of the reaction tube was 100 mm, and the flow rate in the tube at a reaction temperature of 1,250 ° C. was 13 m / sec as a calculated value. After the reaction, cooling air was introduced into the reaction tube so that the high-temperature residence time in the reaction tube was 0.2 seconds, and then ultrafine powder was collected using a Teflon (registered trademark) bag filter.

  When the obtained fine particle titanium oxide was analyzed by Rietan-2000 by the above-described method, it contained 92% of anatase type crystals and 8% of rutile type crystals. Moreover, about the obtained fine particle titanium oxide, 90% cumulative mass particle size distribution diameter D90 in the particle size distribution measured by the laser diffraction type particle size distribution measuring method was 2 μm, and D50 was 1.3 μm. The n value in the Rosin-Rammler equation was 1.9. The n value was obtained from the three-point data obtained by laser diffraction, D10, D50, and D90, plotted as R = 90%, 50%, and 10% on the RR diagram, respectively, and approximated from these three points.

The specific surface area of the obtained vapor phase titanium oxide was measured by the BET method, and a value of 98 m ² / g was obtained. From this specific surface area value, the primary particle size determined by the formula (2) was 15 nm. The tap density was 0.12 g / cm ³ . When m was calculated based on the formula (1), it was 19,500.

(1.2) Preparation of coating material (inorganic binder):
In a Pyrex (registered trademark) container, 30 g of the sol obtained by (liquid phase method particle synthesis) as the particle group B was put. Subsequently, 5 g of water, 10 g of hydroxyzirconium chloride aqueous solution (8% by mass in terms of zirconium oxide), 55 g of alcohol, and 0.5 g of the particle group A-1 synthesized in (1.1) were added and mixed well. While the container was cooled with water, the entire container was placed in a tabletop ultrasonic cleaner for 30 minutes to obtain a coating material. The results of measuring the coating material thus obtained using a laser Doppler particle size distribution meter are shown in FIG. 62 nm and 1260 nm each had a peak of mass particle size distribution. The area of the 62 nm peak was 69%, and the area of the 1260 nm peak was 31%. When measured using a laser diffraction method, the mass particle size distribution had a peak at 2.6 μm. Further, the obtained coating material was dried, and the average primary particle diameter determined from the BET specific surface area of the obtained powder was 11 nm.
When this coating liquid was hung on a 20 cm square clean glass plate until one side was sufficiently wet, it was held vertically for about 1 hour until the liquid was cut and cured for 15 minutes in a constant temperature dryer maintained at 150 ° C., An almost colorless and transparent film was obtained.

(1.3) Preparation of coating material (organic binder):
In a Pyrex (registered trademark) container, 30 g of the sol obtained by (liquid phase method particle synthesis) as the particle group B was put. Subsequently, 55 g of water, 15 g of water-dispersed urethane resin (VONDIC1040NS, manufactured by Dainippon Ink & Chemicals, Inc., 20% by mass in terms of solid urethane resin), and a particle group A-1 synthesized by (1.1) Was mixed well to obtain a coating material. The coating material thus obtained was measured using a laser Doppler type particle size distribution meter, and had a particle size distribution peak at 120 nm and 2110 nm, respectively. The peak area at 120 nm was 61%, and the peak area at 2110 nm was 39%. When measured using the laser diffraction method, the mass particle size distribution had a peak at 2.8 μm. Further, the obtained coating material was dried, and the average primary particle diameter determined from the BET specific surface area of the obtained powder was 11 nm. This coating solution was dropped on a 20 cm square clean glass plate until one side was sufficiently wet, held vertically for about 1 hour until the solution was cut, and cured in a constant temperature drier maintained at 120 ° C. for 15 minutes.

(1.4) Evaluation of photocatalytic film:
(1.2) The glass plate sample obtained in (1.3) was subjected to (deodorization test) (strength test A) (strength test B), and the results are shown in Table 2.

Example 2 :
(2.1) Synthesis of particle group A-2:
A gas containing titanium tetrachloride obtained by mixing gaseous titanium tetrachloride 9.4 Nm ³ / hour and nitrogen 6 Nm ³ / hour is heated to 1,000 ° C., oxygen 10 Nm ³ / hour and water vapor 30 Nm ³ / hour. The mixed oxidizing gas was preheated to 1,000 ° C. and introduced into the reaction tube at a flow rate of 63 m / sec and 73 m / sec using a coaxial parallel flow nozzle, respectively. The inner diameter of the coaxial parallel flow nozzle was 20 mm, and a gas containing titanium tetrachloride was introduced into the inner pipe.

  The inner diameter of the reaction tube was 100 mm, and the flow rate in the tube at a reaction temperature of 1,310 ° C. was 13 m / sec as a calculated value. After the reaction, cooling air was introduced into the reaction tube so that the high-temperature residence time in the reaction tube was 0.2 seconds, and then fine particle powder was collected using a Teflon (registered trademark) bag filter.

The obtained ultrafine titanium oxide had a BET specific surface area of 26 m ² / g and a primary particle diameter of 60 nm. Further, it contained 80% anatase type crystals and 20% rutile type crystals. The obtained fine particle titanium oxide had a 90% cumulative mass particle size distribution diameter D90 of 0.82 μm and D50 of 0.56 μm in the particle size distribution measured by a laser diffraction particle size distribution measurement method. Was 2.6. The tap density wrinkle was 0.28. From these values, the number m of necking calculated from the formula (1) was 57.

(2.2) Preparation of coating material and film formation (inorganic binder):
A coating material was prepared and formed in the same manner as in (1.2) except that the particle group A-2 synthesized in (2.1) was used instead of the particle group A-1. When the coating material was measured using a laser Doppler type particle size distribution analyzer, it had peaks of mass particle size distribution at 73 nm and 1140 nm, respectively, and the area of the peak at 73 nm was 64% and the area of the peak at 1140 nm was 36%. When measured using the laser diffraction method, a mass particle size distribution having a peak at 2.2 μm was obtained. The coating material was dried, and the average primary particle diameter determined from the BET specific surface area of the obtained powder was 12 nm.

(2.3) Preparation of coating material and film formation (organic binder):
A coating material was prepared and formed in the same manner as in (1.3) except that the particle group A-2 synthesized in (2.1) was used instead of the particle group A-1. When the coating material was measured using a laser Doppler type particle size distribution meter, it had a mass particle size distribution peak at 140 nm and 2200 nm, respectively, the area of the 140 nm peak was 62%, and the area of the 2200 nm peak was 38%. When measured using a laser diffraction method, a mass particle size distribution having a peak at 2.5 μm was obtained. The coating material was dried, and the average primary particle diameter determined from the BET specific surface area of the obtained powder was 12 nm.

(2.4) Evaluation of photocatalytic film:
(2.2) The glass plate sample obtained in (2.3) was subjected to (deodorization test) (strength test A) (strength test B), and the results are shown in Table 2.

Example 3 :
(3.1) Synthesis of particle group A-3:
The gas containing a concentration of 100% of the gaseous titanium tetrachloride 11.8 nm ³ / time 1,000 ° C., respectively preheat the 8 Nm ³ / time of oxygen and 20 Nm ³ / time of the mixed gas of water vapor 1,000 ° C. Then, using coaxial parallel flow nozzles, they were introduced into the reaction tube at flow rates of 49 m / sec and 60 m / sec, respectively. The inner diameter of the coaxial parallel flow nozzle was 20 mm, and a gas containing titanium tetrachloride was introduced into the inner pipe.

  The inner diameter of the reaction tube was 100 mm, and the flow rate in the tube at a reaction temperature of 1,320 ° C. was 10 m / sec as a calculated value. After reaction, cooling air was introduced into the reaction tube so that the high-temperature residence time in the reaction tube was 0.3 seconds or less, and then the fine particle powder produced using a Teflon (registered trademark) bag filter was collected. .

The obtained fine particle titanium oxide had a BET specific surface area of 16 m ² / g and a primary particle size of 90 nm. Further, it contained 80% anatase type crystals and 20% rutile type crystals. The obtained fine particle titanium oxide had a 90% cumulative mass particle size distribution diameter D90 of 0.80 μm and D50 of 0.56 in the particle size distribution measured by the laser diffraction particle size distribution measurement method, and the n value in the rosin-Rammler method. Was 2.8. The tap density Ρ was 0.32. From these values, the number m of necking calculated from the formula (1) was 19.

(3.2) Preparation of coating material and film formation:
A coating material was prepared and formed in the same manner as (1.2) except that the particle group A-3 synthesized in (3.1) was used instead of the particle group A-1. When the coating material was measured using a laser Doppler type particle size distribution analyzer, it had a mass particle size distribution peak at 65 nm and 1100 nm, respectively, the area of the 65 nm peak was 70%, and the area of the 1100 nm peak was 30%. When measured using the laser diffraction method, the mass particle size distribution had a peak at 2.0 μm. The coating material was dried, and the average primary particle diameter determined from the BET specific surface area of the obtained powder was 12 nm.

(3.3) Preparation of coating material and film formation (organic binder):
A coating material was prepared and formed in the same manner as (1.3) except that the particle group A-2 synthesized in (3.1) was used instead of the particle group A-1. When the coating material was measured using a laser Doppler type particle size distribution analyzer, it had peaks of mass particle size distribution at 120 nm and 2810 nm, respectively, the peak area at 120 nm was 71%, and the peak area at 2810 nm was 29%. When measured using a laser diffraction method, a mass particle size distribution having a peak at 2.1 μm was obtained. The coating material was dried, and the average primary particle diameter determined from the BET specific surface area of the obtained powder was 12 nm.

(3.4) Evaluation of photocatalytic film:
(3.2) The glass plate sample obtained in (3.3) was subjected to (deodorization test) (strength test A) (strength test B), and the results are shown in Table 2.

Comparative Example 1 :
(4.1) Film formation using only particle group A:
Put 25 g of water in a Pyrex (registered trademark) container, then add 5 g of particle group A-1, 10 g of hydroxyzirconium chloride aqueous solution (8% by mass in terms of zirconium oxide) and 55 g of alcohol, and mix well. Obtained. This coating solution was dropped on a 20 cm square clean glass plate until one side was sufficiently wetted, held vertically for about 1 hour until the solution was cut, and cured for 15 minutes in a constant temperature dryer maintained at 150 ° C. When the coating material was measured using a laser Doppler type particle size distribution meter, a peak of mass particle size distribution was observed at 1300 nm.

(4.2) Preparation of coating material (organic binder):
Pyrex (registered trademark) container is filled with 80 g of water, followed by 5 g of particle group A-1, water dispersion urethane resin (VONDIC 1040NS, manufactured by Dainippon Ink & Chemicals, Inc., 20% by mass in terms of urethane resin solid conversion) ) Was added and mixed well to obtain a coating material. This coating solution was dropped on a 20 cm square clean glass plate until one side was sufficiently wet, held vertically for about 1 hour until the solution was cut, and cured in a constant temperature drier maintained at 120 ° C. for 15 minutes. When the coating material was measured using a laser Doppler type particle size distribution meter, a peak of mass particle size distribution at 2200 nm was observed.

(4.3) Evaluation of photocatalytic film:
(3.2) The glass plate sample obtained in (3.3) was subjected to (deodorization test) (strength test A) (strength test B), and the results are shown in Table 2.

Comparative Example 2 :
(5.1) Film formation using only the particle group B:
In a Pyrex (registered trademark) container, 33 g of the particle group B obtained by (liquid phase method particle synthesis), 2 g of water, 10 g of a hydroxyzirconium chloride aqueous solution (8% by mass in terms of zirconium oxide), and 55 g of alcohol And mixed well to obtain a coating material. When the coating material was measured using a laser Doppler particle size distribution analyzer, it had a peak of mass particle size distribution at 90 nm. When measured using a laser diffraction method, a broad distribution having no clear peak at 0.2 to 2.0 μm was observed. This coating solution was dropped on a 20 cm square clean glass plate until one side was sufficiently wetted, held vertically for about 1 hour until the solution was cut, and cured for 15 minutes in a constant temperature dryer maintained at 150 ° C.

(5.2) Preparation of coating material (organic binder):
33 g of particle group B obtained by (liquid phase method particle synthesis) is placed in a Pyrex (registered trademark) container, 52 g of water is added, and a water-dispersed urethane resin (VONDIC1040NS, manufactured by Dainippon Ink & Chemicals, Inc., urethane) 15 g of 20 mass% in terms of resin solids) was added and mixed well to obtain a coating material. When the coating material was measured using a laser Doppler type particle size distribution meter, it had a peak of mass particle size distribution at 160 nm. When measured using the laser diffraction method, a broad distribution having no clear peak at 0.2 to 2.6 μm was observed. This coating solution was dropped on a 20 cm square clean glass plate until one side was sufficiently wet, held vertically for about 1 hour until the solution was cut, and cured in a constant temperature drier maintained at 120 ° C. for 15 minutes.

(5.3) Evaluation of photocatalytic film:
(5.1) (Deodorization test) (Strength test A) (Strength test B) were performed on the glass plate samples obtained in (5.2), and the results are shown in Table 2.

Example 4 : Coating material containing PTFE (6.1): Preparation of coating material In a Pyrex (registered trademark) container, 70 g of the particle group obtained by (liquid phase method particle synthesis) is placed, 12 g of water is placed, and chlorination is performed. 12 g of hydroxyzirconium aqueous solution (15 mass% concentration in terms of zirconium oxide), 4 g of polytetrafluoroethylene dispersion (powder solid content concentration of 60 mass%, manufactured by Asahi Glass Co., Ltd., AD911) having a particle diameter of 0.25 μm, 1 g of a 1% by mass aqueous solution of dodecylbenzenesulfonic acid was added, and 1.0 g of the particle group A-1 synthesized in (1-1) was added and mixed well to obtain a coating material.

(6.2) Film formation of coating material:
This coating solution was dropped on a 7.5 cm square clean glass plate until one side was sufficiently wet, kept vertically for about 1 hour until the solution was drained, and cured for 15 minutes in a constant temperature dryer maintained at 150 ° C. .

(6.3) Evaluation of photocatalytic film:
The glass plate sample obtained in (6.2) was subjected to (performance reduction confirmation due to contamination) (strength test A) (strength test B), and the results are shown in Table 3.
Example 5 : Twice coating of coating material having different particle size distribution (7.1): Preparation of coating material In a Pyrex (registered trademark) container, a sol obtained by (liquid phase method particle synthesis) as a particle group B was added. 46.7 g. Subsequently, 1.3 g of water, 6 g of a hydroxyzirconium chloride aqueous solution (20% by mass in terms of zirconium oxide), 40 g of alcohol, and 5 g of the particle group A-1 synthesized in (1.1) were mixed well, While the container was cooled with water, the entire container was placed on a tabletop ultrasonic cleaner for 30 minutes to obtain a coating material.
(7.2): Preparation of coating material for topcoat In a Pyrex (registered trademark) container, 10 g of the particle group obtained by (liquid phase method particle synthesis) is put, 15.8 g of water is put, hydroxyzirconium chloride aqueous solution (oxidation) A coating material was obtained by mixing 2.2 g of 10 mass% in terms of zirconium), 70 g of alcohol, and 1 g of a 1 mass% aqueous solution of dodecylbenzenesulfonic acid and mixing well.

(7.3) Coating material deposition:
This coating solution (7.1) is dropped on a 7.5 cm square clean glass plate until one side is sufficiently wet, and is kept vertically for about 1 hour until the solution is cut, and is kept in a constant temperature dryer maintained at 150 ° C. for 15 hours. Curing was performed for a minute.
After the coating film has cooled to room temperature, the overcoating liquid (7.2) is further dropped onto the coating film until it is sufficiently applied, and the liquid is kept vertically for about 1 hour until the liquid has been cut off, and maintained at 150 degrees. Curing was carried out for 15 minutes.

(7.4) Evaluation of photocatalytic film:
The glass plate sample obtained in (7.3) was subjected to (Performance degradation confirmation due to contamination) (Strength test A) (Strength test B), and the results are shown in Table 3.
Example 6 :
(8.1) Coating material containing activated alumina:
(8.1): Preparation of coating material 16 g of the sol obtained by (liquid phase method particle synthesis) as particles was placed in a Pyrex (registered trademark) container. Then, 8.7 g of water, 4.5 g of hydroxyzirconium chloride aqueous solution (10% by mass in terms of zirconium oxide), 70 g of alcohol, 0.4 g of activated alumina (manufactured by Sumitomo Chemical Co., Ltd., KC-501) Then, 0.4 g of the particle group A-1 synthesized in (1.1) was put, and the container was placed in a tabletop ultrasonic cleaner for 30 minutes while cooling the container with water to obtain a coating material.

(8.2) Film formation of coating material:
This coating liquid (8.1) is dropped on a 7.5 cm square clean glass plate until one side is sufficiently wet, and is kept vertically for about 1 hour until the liquid is cut, and is kept in a constant temperature dryer maintained at 150 ° C. for 15 hours. Curing was performed for a minute.
(8.3) Evaluation of photocatalytic film:
The glass plate sample obtained in (8.2) was subjected to (confirmation of performance deterioration due to contamination) (strength test A) (strength test B), and the results are shown in Table 3.
Example 7 : Coating material containing chemical trapping material (9.1): Preparation of coating material In a Pyrex (registered trademark) container, 16 g of sol obtained by (liquid phase method particle synthesis) was put as particles. Subsequently, 8.7 g of water, 4.5 g of an aqueous zirconium zirconium chloride solution (10% by mass in terms of zirconium oxide), 70 g of alcohol, and 0.4 g of calcium chloride dihydrate (manufactured by Kanto Chemical Co., Ltd., special grade) ), 0.4 g of the particle group A-1 synthesized in (1.1) was added, and the container was placed in a tabletop ultrasonic cleaner for 30 minutes while cooling the container with water to obtain a coating material.

(9.2) Film formation of coating material:
This coating liquid (9.1) is dropped on a clean 7.5 cm square glass plate until one side is sufficiently wet, and is kept vertically for about 1 hour until the liquid is cut, and is kept in a constant temperature dryer maintained at 150 ° C. for 15 hours. Curing was performed for a minute.
(9.3) Evaluation of photocatalytic film:
The glass plate sample obtained in (9.2) was subjected to (performance degradation confirmation due to contamination) (strength test A) (strength test B), and the results are shown in Table 3.
Example 8 : Coating material containing platinum and transition metal oxide (10.1): Adjustment of additive 0.08 g of nickel oxide (Kanto Chemical Co., Ltd., Shika Special Grade), cobalt oxide (Kanto Chemical Co., Ltd., Deer) 0.12 g, Molybdenum oxide (Kanto Chemical Co., Ltd., Shika Special Grade) 0.6 g in a 100 ml container for rocking mill, 13.6 g of water, 2.0 g of 1% by weight aqueous solution of dodecylbenzenesulfonic acid, 0 g 20 g of zirconia balls having a diameter of 2 mm were put and dispersed at 600 rpm for 3 hours using a rocking mill.
(10.2): Preparation of Coating Material 16 g of the sol obtained as (particle synthesis by liquid phase method) as particles was placed in a Pyrex (registered trademark) container. Subsequently, 70 g of alcohol and 0.2% by mass of hexachloroplatinic acid hexahydrate with respect to titanium oxide in terms of platinum metal were added and mixed well, and then the sample was placed in a petri dish having a diameter of 12 cm, and the petri dish was covered. While stirring with a magnetic stirrer from the outside, the light from the high-pressure mercury lamp was irradiated for 2 hours so that the integrated value of the amount of ultraviolet light having a wavelength of 310 nm or more and 390 nm or less was 20 mW / cm ^2. Was used to deposit platinum metal on the titanium oxide surface. 8.2 g of the slurry sample prepared in (10.1) is added to the titanium oxide sol to which platinum is adhered, and 4.5 g of a hydroxyzirconium chloride aqueous solution (10% by mass in terms of zirconium oxide) is added, and (1 0.4 g of the particle group A-1 synthesized in 1) was added and stirred well. While the container was cooled with water, the entire container was placed in a tabletop ultrasonic cleaner for 30 minutes to obtain a coating material.

(10.3) Coating material deposition:
This coating solution (10.2) is dropped on a clean 7.5 cm square glass plate until one side is sufficiently wet, held vertically for about 1 hour until the solution has been drained, and kept in a constant temperature dryer maintained at 150 ° C. for 15 hours. Curing was performed for a minute.
(10.4) Photocatalytic film evaluation:
The glass plate sample obtained in (10.3) was subjected to (performance reduction confirmation due to contamination) (strength test A) (strength test B), and the results are shown in Table 3.
Example 9 : Coating material containing partially hydrolyzed product of ceramic fiber and alkoxysilane (11.1): Adjustment of binder 7 g of tetraethylorthosilicate was dissolved in 38 g of 80% by weight ethanol aqueous solution and cut to 0.5 mm. 5 g of cotton-like 4 μm-diameter quartz glass fiber was added, and the mixture was kneaded for 30 minutes with a rotation / revolution kneader. This was adjusted to pH = 2 by adding nitric acid, and polymerized by maintaining at 40 ° C. for 4 hours while stirring to obtain a binder solution. The kinematic viscosity of this liquid was 8.0 cSt.
(11.2): Preparation of coating material In a Pyrex (registered trademark) container, 43 g of the sol obtained by (liquid phase method particle synthesis) was put as particles, and the particle group A- synthesized in (1.1) 1 g of 1 was added, and 1.0 g of a 1% by mass aqueous solution of dodecylbenzenesulfonic acid was added. While cooling the container with water, the whole container was placed on a tabletop ultrasonic cleaner for 30 minutes, and this was further mixed with the whole amount of the binder prepared in (11.1) to obtain a coating material.
(11.3) Coating material deposition:
This coating solution (11.2) is dropped on a clean 7.5 cm square glass plate until one side is sufficiently wet, and is kept vertically for about 1 hour until the solution is drained, and is kept in a constant temperature dryer maintained at 150 ° C. for 15 hours. Curing was performed for a minute.
(11.4) Evaluation of photocatalytic film:
The glass plate sample obtained in (11.3) was subjected to (confirmation of performance degradation due to contamination) (strength test A) (strength test B), and the results are shown in Table 3.
Comparative Example 3 :
(12.1) Film formation only by particle group B (low concentration):
In a Pyrex (registered trademark) container, 6.7 g of a particle group obtained by (liquid phase method particle synthesis) is put, 1.5 g of a hydroxyzirconium chloride aqueous solution (10% by mass in terms of zirconium oxide) is put, and 90. 8 g was added and 1 g of a 1% by mass aqueous solution of dodecylbenzenesulfonic acid was added and mixed well to obtain a coating material.
(12.2) Coating material deposition:
This coating liquid (12.1) is dropped on a 7.5 cm square clean glass plate until one side is sufficiently wet, and is kept vertically for about 1 hour until the liquid has been drained. Curing was performed for a minute.
(12.3) Evaluation of photocatalytic film:
The glass plate sample obtained in (12.2) was subjected to (performance reduction confirmation due to contamination) (strength test A) (strength test B), and the results are shown in Table 3.
Comparative Example 4 :
(13.1) Film formation only with particle group B (high concentration):
In a Pyrex (registered trademark) container, 87 g of the particle group obtained by (liquid phase method particle synthesis) is placed, 9.8 g of a hydroxyzirconium chloride aqueous solution (20% by mass in terms of zirconium oxide) is placed, and 2.2 g of water is placed. 1 g of a 1% by weight aqueous solution of dodecylbenzenesulfonic acid was added and mixed well to obtain a coating material.
(13.2) Coating material deposition:
This coating liquid (12.1) is dropped on a 7.5 cm square clean glass plate until one side is sufficiently wet, and is kept vertically for about 1 hour until the liquid is cut off, and is kept in a constant temperature dryer maintained at 150 ° C. for 15 hours. Curing was performed for a minute.
(13.3) Evaluation of photocatalytic film:
The glass plate sample obtained in (13.2) was subjected to (Performance degradation confirmation due to contamination) (Strength test A) (Strength test B), and the results are shown in Table 3.

It is a SEM photograph of necking particles. It is a conceptual diagram of the film | membrane of this invention. It is a mass particle size distribution of liquid phase method particles. It is this invention Example 1 (1.2) and the mass particle size distribution of a coating material.

Explanation of symbols

B Contact point A Necking

Claims (66)

  The number of necking particles of particle group A, including particle group A, particle group B, and solvent (the total number of particles constituting all necking particles, with the individual particles being necked as units). ) Is larger than the number of necking particles in the particle group B.   A coating material comprising a metal oxide particle group A having a necking structure in which m particles are connected, a metal oxide particle group B having only 0.2 m particles or less, and a solvent.   The coating material of Claim 2 whose average primary particle diameter by the BET specific surface area conversion value of the particle group A is 7 nm or more and 200 nm or less.   The coating material according to any one of claims 1 to 3, wherein the particle size distribution of the particle group A is a distribution constant of 1.5 or more according to the Rosin Ramler equation.   The coating material according to any one of claims 1 to 4, wherein the particle group A contains titanium oxide.   The coating material of any one of Claims 1-5 whose average particle diameter measured using the laser diffraction type particle size distribution measuring device of the particle group A is 50 nm-3 micrometers.   The coating material of any one of Claims 1-6 in which the particle group A contains the titanium oxide synthesize | combined by the vapor phase method manufactured by oxidizing titanium tetrachloride with oxidizing gas at high temperature.   Particle group A reacts after preheating a gas containing titanium tetrachloride and an oxidizing gas to 500 ° C. or more, respectively, so that the average primary particle diameter in terms of BET specific surface area is 7 nm or more and 500 nm or less. The coating material of any one of Claims 1-7 containing titanium.   The particle group A includes titanium oxide synthesized by supplying a gas containing titanium tetrachloride and an oxidizing gas, each preheated to 500 ° C. or more, to the reaction tube at a flow rate of 10 m / second or more. The coating material of any one of -8.   The titanium oxide of the particle group A retains the titanium tetrachloride-containing gas and the oxidizing gas in the reaction tube for a period of 1.0 second or less under a high temperature condition in which the temperature in the reaction tube exceeds 600 ° C. The coating material according to claim 9, which is synthesized by reacting.   The coating material according to claim 9 or 10, wherein the titanium oxide of the particle group A is synthesized with an average flow rate of the gas in the reaction tube of 5 m / sec or more.   The titanium oxide of the particle group A was synthesize | combined by supplying the gas and oxidizing gas containing preheated titanium tetrachloride in a reaction tube, and producing a turbulent airflow. Coating material.   The coating material according to any one of claims 7 to 12, wherein the titanium oxide of the particle group A is synthesized by containing 10 to 100% of titanium tetrachloride in the gas containing titanium tetrachloride.   The coating material according to any one of claims 7 to 13, wherein the titanium oxide of the particle group A is synthesized at a temperature for preheating the gas containing titanium tetrachloride and the oxidizing gas at 800 ° C or higher.   The coating material of any one of Claims 1-14 whose average primary particle diameter by the BET conversion value of the particle group B is 4 nm or more and 100 nm or less.   The coating material according to claim 15, wherein an average particle diameter of the particle group B measured by a laser diffraction particle size distribution analyzer is 4 nm or more and 2000 nm or less.   The coating material of Claim 16 whose average particle diameter by the laser Doppler type particle size distribution measurement of the particle group B is 8 nm or more and 100 nm or less.   The coating material according to any one of claims 15 to 17, wherein the particle group B contains titanium oxide synthesized by hydrolyzing a titanium compound aqueous solution in water.   The coating material according to any one of claims 15 to 18, wherein the particle group B includes titanium oxide synthesized by a manufacturing method in which a titanium tetrachloride aqueous solution is dropped into water.   The coating material according to claim 19, wherein the titanium oxide of the particle group B is synthesized by a production method in which a titanium tetrachloride aqueous solution is dropped into water heated to 50 ° C to the boiling point.   The coating material according to any one of claims 1 to 20, wherein a ratio X / Y of the mass X of the particle group A and the dry mass Y of the particle group B is 0.01 or more and 0.2 or less.   The solid content concentration (X + Y) / Z is 0.005 or more and 0.1 or less when the mass X of the particle group A, the dry mass Y of the particle group B, and the mass Z of the entire coating material are given. 21. The coating material according to any one of 21.   A coating material containing a metal oxide, comprising a particle group Ba having a peak at 8 nm or more and 400 nm or less and a particle group Aa having a peak at 800 nm or more and 5500 nm or less in a mass particle size distribution of a laser Doppler method.   24. The coating material according to claim 23, comprising a particle group Ba having a peak at 20 nm to 300 nm and a particle group Aa having a peak at 1200 nm to 4000 nm in the mass particle size distribution of the laser Doppler method.   25 or 23 in which the ratio of AaS / BaS is 0.05 or more and 1 or less, where BaS is the integrated area of the particle group Ba and AaS is the integrated area of the particle group AaS in the mass particle size distribution of the laser Doppler method. The coating material as described in.   A coating material containing a metal oxide, having a peak Ab in at least 1 μm to 4 μm in the mass particle size distribution of the laser diffraction method, and having a primary particle diameter converted from a BET measurement value of a dry powder of the coating material The coating material which is 7 nm or more and 50 nm or less.   A coating material comprising titanium oxide synthesized by a gas phase method of producing titanium tetrachloride by oxidizing at high temperature with an oxidizing gas, titanium oxide synthesized by hydrolyzing a titanium compound aqueous solution in water, and a solvent.   The ratio of the dry mass of titanium oxide synthesized by a vapor phase method in which titanium tetrachloride is oxidized at high temperature with an oxidizing gas and titanium oxide synthesized by hydrolyzing a titanium compound aqueous solution in water is 0.01. The coating material according to claim 27, wherein the coating material is 0.2 or more and 0.2 or less.   The coating material according to any one of claims 1 to 28, comprising an inorganic binder.   30. The coating material according to any one of claims 1 to 29, comprising an organic binder.   30. The coating material according to claim 29, wherein the inorganic binder contains a zirconium compound.   The coating material according to any one of claims 1 to 31, comprising a fluororesin.   32. The coating material according to claim 31, wherein the fluororesin contains polytetrafluoroethylene.   The coating material according to claim 32 or 33, wherein the particle size of the fluororesin is 0.01 µm or more and 2 µm or less.   The coating material according to claim 34, wherein the particle size of the fluororesin is 0.05 µm or more and 0.5 µm or less.   The coating material according to any one of claims 32 to 35, further comprising a surfactant of 0.5 mass% or more and 10 mass% or less with respect to the weight of the fluororesin.   The coating material according to claim 36, wherein the surfactant is nonionic.   The coating material according to any one of claims 1 to 37, wherein a film having a strength of H or higher in a pencil strength test can be formed by heat drying at 200 ° C or lower.   The coating material according to any one of claims 1 to 38, wherein a concentration of a solid content in the coating material is 10% by mass or more.   The coating material according to any one of claims 1 to 39, wherein 50% by mass or more of the solid content is titanium oxide.   The coating material according to claim 40, wherein the solid content is 60% by mass or more of titanium oxide.   Among the binders blended in the coating material, the inorganic type is Iw [g] in terms of 120 ° C. dry solid, and the fluororesin is Fw [g] in terms of 120 ° C. dry solid The coating material according to any one of claims 32 to 41, wherein Iw / Fw is 0.05 or more and 20.0 or less.   The coating material according to any one of claims 1 to 42, comprising an anionic surfactant in an amount of 10 ppm to less than 2000 ppm.   The coating material according to any one of claims 1 to 42, comprising a cationic surfactant in an amount of 10 ppm or more and less than 2000 ppm.   The coating material according to any one of claims 1 to 42, comprising a nonionic surfactant in an amount of 2 ppm or more and less than 2000 ppm.   The coating material according to claim 45, comprising a nonionic surfactant in an amount of 2 ppm or more and less than 50 ppm.   The coating material according to any one of claims 1 to 46, which contains titanium oxide and a partial hydrolyzate of alkoxysilane as a solid content.   The coating according to any one of claims 1 to 47, comprising an inorganic binder and ceramic fibers having a diameter of 0.5 to 10 µm with respect to titanium oxide and having a diameter of 0.5 to 10 µm. Wood. It is applied to an area of 56.25 cm ² containing photocatalyst fine particles, contaminated in an irradiation environment at 10000 lux in an air diluted SO ₂ gas at 20 ° C., 50% relative humidity, 5 L, 50 ppm for 12 hours. When an acetaldehyde gas removal test is performed at 50 ° C., relative humidity 50%, 500 ml, 500 ppm, the removal rate before contamination is a% and the removal rate after contamination is b%, b / a becomes 0.5 or more. Coating material that can create a photocatalytic film.   At least one physical adsorbent selected from the group consisting of activated alumina, A-type zeolite, Y-type zeolite and activated carbon is blended in an amount of 10% by mass to 200% by mass with respect to the photocatalyst fine particles. The coating material according to any one of claims 1 to 49.   51. The coating material according to claim 50, wherein the activated alumina, A-type zeolite, Y-type zeolite and activated carbon have a particle size of 5 nm or more and 5 μm or less.   The photocatalyst fine particles are contained, and at least one of copper oxide, iron oxide, manganese oxide, and zinc oxide is contained as a chemical trapping material in an amount of 0.01% by mass to 200% by mass in terms of metal with respect to the photocatalyst fine particles. The coating material according to any one of 1 to 51.   0.01% in terms of metal with respect to the photocatalyst fine particles, containing the photocatalyst fine particles, and using at least one of alkaline earth metal chloride, alkaline earth metal carbonate, and alkaline earth metal hydrogen carbonate as a chemical trapping material. 53. The coating material according to any one of claims 1 to 52, comprising 200% by mass or less.   54. The coating material of claim 53, wherein the alkaline earth metal chloride is calcium, strontium or barium chloride.   The photocatalyst fine particles are contained, and at least one of nickel oxide, cobalt oxide, and molybdenum oxide is contained in an amount of 0.1% by mass to 200% by mass with respect to the photocatalyst particles. The coating material according to item.   The platinum metal or a platinum compound is further included, and the sum of the weights of one or more of nickel oxide, cobalt oxide, and molybdenum oxide with respect to platinum is 20% by mass to 10,000% by mass. The coating material as described in.   57. The coating material according to claim 55 or 56, wherein the d50 particle diameter of platinum, a compound thereof, and a transition metal oxide is 10 nm or more and 10 μm or less.   Manufacture of a coating material including a step of mixing a metal oxide particle group A having a necking structure in which m particles are connected, a metal oxide particle group B having only 0.2 m particles or less, and a solvent. Method.   57. After applying and drying the coating material according to any one of claims 1 to 56 having a solid content concentration of 5% by mass or more and less than 35% by mass, the solid content concentration is 1/2% by mass of the first coating material. A method for producing a film, in which a coating material containing the following particle group B and a binder is applied and dried.   A film made from the coating material according to any one of claims 1 to 57.   The film according to claim 60, wherein the film has an average film thickness of 50 nm or more and 30000 nm or less.   The film according to claim 60, wherein the film has an average film thickness of 50 nm or more and 2000 nm or less.   The film according to claim 60, wherein the film has an average film thickness of 1/10 to 5 times the aggregated particle diameter of the particle group A.   64. An article comprising the film according to any one of claims 60 to 63 on a surface or inside thereof.   An article having at least one function among photocatalytic functions such as deodorization, antifouling, and antibacterial.   Articles include building materials, lighting equipment, design window glass, machinery, vehicles, glass products, household appliances, agricultural materials, electronic equipment, mobile phones, tools, tableware, bath products, pure water production equipment, toilet articles, furniture, clothing , Cloth products, textiles, leather products, paper products, resin products, sports equipment, futons, containers, glasses, signs, piping, wiring, metal fittings, sanitary materials, automobile supplies, stationery, emblems, hats, bags, shoes, umbrellas, blinds , Balloons, piping, wiring, metal fittings, fluorescent lights, LEDs, traffic lights, street lights, toys, road signs, decorations, tents, cooler boxes and other outdoor products, artificial flowers, objects, filters, deodorant filters 66. The article of claim 64 or 65, wherein the article is at least one selected from the group consisting of: