JPH11279446A - Photocatalytic coating material, its production and photocatalytic deodorizing paper produced by using the coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photocatalytic coating material free from problems of coagulation, powdering and cracking in case of applying to paper, etc., while keeping plasticity which is a merit of organic binders and oxidation resistance which is a merit of inorganic binders by compounding an inorganic binder, a photocatalyst, a polyvinyl alcohol and an organic binder. SOLUTION: The objective coating material is composed of (A) an inorganic binder (e.g. colloidal silica), (B) a photocatalyst (preferably titanium oxide), (C) a polyvinyl alcohol and (D) an organic binder (preferably a dispersion of a thermoplastic polymer having high oxidative deterioration resistance such as silicone resin). The amounts of the components A, B, C and D are 10-50 wt.%, 30-80 wt.%, 0.1-10 wt.% and 1-30 wt.% based on the coating material, respectively. The coating material can be produced by successively adding the components B, C and D to an aqueous dispersion of the component A under agitation. A photocatalytic deodorizing paper produced by coating a base paper with the coating material can be used in air cleaner, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocatalytic paint using a photocatalyst, a method for producing the same, and a photocatalytic deodorizing paper using the paint. The present invention relates to a photocatalyst paint capable of avoiding aggregation and gelation in order to avoid direct contact between the organic binder and the photocatalyst, a method for producing the same, and a photocatalytic deodorizing paper using the paint.

[0002]

2. Description of the Related Art In recent years, as environmental reviews including environmental assessments are being conducted on a global scale, people are increasingly motivated to review their surroundings in order to further improve their living environments. In the last few years, words such as "antibacterial", "antifungal" and "bactericidal effect" have been frequently seen in daily life. For example,
Words such as "antibacterial" are often added as a function of increasing the commercial value, such as a mechanical pen, a ballpoint pen, a notebook, an automobile handle, a sheet, a plastic kitchen utensil, and the like.

[0003] One of the reasons for the public's particular interest in antibacterial activity is that the outbreak of pathogenic E. coli O-157 in 1996 caused many deaths. The incident has triggered more antimicrobial products on the market. On the other hand, HIV and MRSA hospital-acquired infections are unavoidable problems that will become major social problems in the aging society of the 21st century. Therefore, in recent years, photocatalysts have been spotlighted as one means for solving such problems. Above all, photocatalytic titanium oxide, which has excellent photocatalytic ability and is safe for the human body, is often used, and research and development in various forms are being carried out.

[0004] Titanium oxide, one of the photocatalysts, has been used industrially as a white pigment in a wide range of fields such as papermaking, plastics, paints, and cosmetics. The reason is that titanium oxide functions as an ultraviolet absorber to absorb ultraviolet light of 300 to 400 nm well and is inexpensive.

When titanium oxide itself is used as an ultraviolet absorber, the titanium oxide absorbs ultraviolet rays and generates electron and hole pairs, and the hole pairs react with water on the surface to form hydroxyl groups having strong oxidizing power. Generates active oxygen species such as radicals. Therefore, conventionally, titanium oxide that has been subjected to a surface treatment to prevent the reaction between the hole pair and moisture and suppress the generation of active oxygen species has been used as an ultraviolet absorber.

[0006] In recent years, photocatalysts such as titanium oxide have been reviewed, and a movement has been taking place in the industry to actively exert oxidizing power, which has been regarded as a drawback. Namely, the oxidizing power of the active oxygen species of most organic substances and NO _X and S
Inorganic materials such as O _X has been found to have ability to resolve, JP-A 7-102678 and JP-A No. 8-1
Japanese Patent No. 75887 discloses a ceramic or ceramic structure for preventing hospital-acquired infection, and Japanese Patent Application Laid-Open No. 8-173520 discloses a decorative article for environmental purification.

One of the reasons why the photocatalyst having this photocatalytic effect has been reconsidered is that, as a deodorant, it is permanent unlike an adsorbent deodorant such as activated carbon, and when viewed as a disinfectant, it is chlorinated, acidic, and so on. It is harmless without affecting the human body like alkaline germicides.

[0008] The application of photocatalyst to paper has been extremely difficult because the photocatalyst decomposes adjacent cellulose fibers and causes a decrease in strength. But to solve that problem,
Japanese Patent Application Laid-Open No. Hei 8-26660 discloses a titanium oxide internal paper capable of suppressing the decrease in strength by previously aggregating photocatalytic titanium oxide in water to reduce the area in contact with cellulose fibers.
Japanese Patent Application Laid-Open No. Hei 8-266601 proposes a method in which fine fibers and titanium oxide are aggregated to utilize hydrogen bonding of cellulose fibers in order to improve the yield of photocatalyst. Japanese Patent Application Laid-Open No. 8-12 / 1996 discloses a method in which the transparency of the entire paper is improved in order to effectively utilize the photocatalyst inside the paper, and light is transmitted to the internal photocatalyst.
No. 0594.

As a method for supporting a photocatalyst on paper, there are an internal addition method obtained by internally adding a raw material and making a paper by a conventional method, and a coating method of applying a material prepared by coating a photocatalyst. As a coating method, JP-A-8-173805 discloses a method in which a cellulose fiber used for a base paper is treated with a water-soluble inorganic substance, water-insolubilized to form a base paper, and a photocatalytic titanium oxide layer is provided thereon. In the gazette, in order to further prevent direct contact between the base paper and the photocatalyst, a method in which a film-forming inorganic material-containing layer is provided between the base paper and the photocatalyst layer to suppress a decrease in strength and improve durability. Is disclosed in JP-A-8-1
No. 73762. JP-A-9-234375 proposes a deodorized paper provided with a photocatalyst removal layer using colloidal silica and a thermoplastic polymer emulsion in combination.

[0010]

The method of supporting a photocatalyst on paper can be roughly classified into an internal addition method and a coating method. However, since the photocatalyst is basically a surface reaction, the photocatalytic reaction can be efficiently carried out. For this to occur, it is indispensable that the photocatalyst is exposed to light and that the substance to be decomposed contacts or approaches the photocatalyst. Considering this, it can be seen that the internal addition method is not an effective method because light does not completely pass through to the inside of the paper. Therefore, light can easily reach the photocatalyst,
Considering that the decomposable substance is easily contacted or approached, it is clear that a coating method in which a photocatalyst is coated on paper and present on the surface as a photocatalyst coating layer is excellent.

However, according to the contents of the above-mentioned publications, when coating is performed on flexible paper, in a coating layer using only an organic binder, the organic binder is decomposed with light irradiation and causes powder drop. In the case of a coating layer using only an inorganic binder, the adhesive strength to the base paper is insufficient, and cracking due to bending occurs, so that processing such as corrugating is difficult.

Depending on the type of the organic binder, when the photocatalyst and the organic binder come into contact with each other (mixing), agglomeration occurs due to the high reactivity of the photocatalyst itself, or coagulation occurs in the preparation of a paint and in the application of coated paper. It was found that many objects appeared on the coated surface.

[0013]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, the combined use of a photocatalyst, an organic binder, an inorganic binder and polyvinyl alcohol has the advantage of an organic binder. It has been found that the above problem can be solved while taking advantage of the plasticity and the advantage of being hardly oxidized and decomposed, which are the advantages of an inorganic binder.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The photocatalyst paint of the present invention and the coating layer of the photocatalytic deodorizing paper using the paint must have at least one surface composed of a base paper, a photocatalyst, an organic binder, an inorganic binder and polyvinyl alcohol. It is. In addition, as a method for producing a photocatalytic coating, it is necessary to add an inorganic binder, a photocatalyst, polyvinyl alcohol, and an organic binder in this order.

The photocatalyst used in the present invention includes metal oxides such as titanium oxide, zinc oxide, tin oxide, tungsten oxide, niobium oxide, zirconium oxide, cerium oxide, cadmium sulfide, zinc sulfide, lead sulfide, copper sulfide, and the like. At least one known photocatalyst particle such as a metal sulfide such as molybdenum sulfide can be selected and used. Among them, titanium oxide is preferred because of its excellent photocatalytic activity, chemical stability, harmlessness to the human body, and relatively low cost.
The amount of the photocatalyst to be added is preferably 30 to
80% by weight. When the amount is less than 30% by weight, the photocatalytic performance is insufficient, and when the amount is more than 80% by weight, the binder is insufficient.

The titanium oxide described in the present invention means various titanium oxides such as anatase-type titanium oxide, rutile-type titanium oxide, amorphous titanium oxide, metatitanic acid, orthotitanic acid, titanium hydroxide, and hydrous titanium oxide. I do.

In order for the photocatalyst of the present invention to decompose harmful substances and the like by a photocatalytic reaction, it is necessary to irradiate the photocatalyst with light having a wavelength having an energy greater than the band gap. Therefore resulting reactive oxygen species ^{_{(OH ·, · O 2 -}} , such as H ₂ O ₂₎
Decomposes harmful substances and finally to end products such as carbon dioxide and water. By such an action,
Bactericidal and antibacterial effects occur.

Examples of harmful substances include aldehydes,
Amines, there hydrocarbons such as alcohols, trihalomethane, tetrachlorethylene, the organic halogen compounds Freon or SO _X, NO _X and the like. In addition, degradable substances include BOD, pesticides, proteins, amino acids and the like, and sterilization of fungi, molds and the like is also possible.

The light source for irradiating the photocatalyst with light having a wavelength having a band gap energy or more, that is, light having a wavelength of 400 nm or less, includes ultraviolet light such as sunlight, a fluorescent lamp, a mercury lamp, a xenon lamp, and a black light. Is mentioned.

As the organic binder of the photocatalyst used in the photocatalyst-containing layer, it is preferable to use one in which a thermoplastic polymer resistant to oxidative deterioration such as a fluororesin such as polytetrafluoroethylene emulsion or a silicon resin is dispersed. Any thermoplastic polymer that can be dissolved or dispersed in water can be used. Examples of usable organic binders include styrene-butadiene latex, modified styrene-butadiene latex, acrylonitrile-butadiene latex, methyl methacrylate-butadiene latex, and modified methyl methacrylate-
Aqueous latex such as butadiene latex, chloroprene latex, butyl latex, polybutene latex, polyurethane latex, thiochol latex, polyethylene emulsion, ethylene vinyl acetate emulsion, vinylidene chloride emulsion, vinyl chloride emulsion, acrylic resin emulsion, and polytetrafluoroethylene emulsion And water-based emulsions can be used alone or in combination of two or more. The addition amount of the organic binder is preferably 1 to 30% by weight of the photocatalytic paint. If the amount is less than 1% by weight, when coated on a base paper or the like, the coating layer loses its flexibility and cracks easily occur. If the amount is more than 30% by weight, the surface of the photocatalyst is largely changed due to too much organic binder. This is because the photocatalyst performance is insufficient at the initial stage of light irradiation.

As the polyvinyl alcohol used in the present invention, any polyvinyl alcohol can be used as long as it is soluble in water or hot water and does not easily solidify or precipitate upon cooling. When polyvinyl alcohol is used, it is dissolved in water or hot water and used as an aqueous solution. Since polyvinyl alcohol is a material with excellent film-forming properties, it forms a very thin film on the surface of the photocatalyst powder, and suppresses the aggregation of the organic binder and photocatalyst when they come into direct contact with the paint. Have. When the photocatalyst deodorizing paper of the present invention is irradiated with light, a very thin film covering the photocatalyst is decomposed by photocatalysis in a short time to form water and carbon dioxide. Therefore, the photocatalysis is not hindered. The added amount of polyvinyl alcohol is preferably 0.1 to 30% by weight of the photocatalytic paint. If the amount is less than 0.1% by weight, the surface of the photocatalyst cannot be sufficiently covered, which causes aggregation and gelation. If the amount is more than 30% by weight, the thickness of the film becomes thick as in the case of the organic binder, resulting in insufficient photocatalytic performance at the initial stage of light irradiation.

When preparing a paint, it is necessary to add polyvinyl alcohol before adding an organic binder. The reason for this is that it is necessary to form a thin film on the photocatalyst surface and to suppress aggregation by contact between the photocatalyst and the organic binder. Since the photocatalyst powder protected by the thin film becomes a kind of protective colloid, the effect of quickly cleaning the paint adhered to the inside of the coating machine or the like is also exhibited.

As the inorganic binder used in the present invention, film-forming inorganic substances such as colloidal silica, alumina sol, saponite, hectorite, smectite, and sepiolite can be used. Inorganic compounds capable of acting as a binder are listed. It can be used without being limited to the inorganic compounds described above. The addition amount of the inorganic binder is preferably 10 to 50% by weight of the photocatalytic paint. If the amount is less than 10% by weight, powder fall occurs due to photocatalysis by light irradiation. If the content is more than 50% by weight, the surface of the photocatalyst is covered, and the inorganic binder is not decomposed even by light irradiation, so that the photocatalytic ability is permanently insufficient.

In the photocatalyst containing layer of the present invention, it is essential to use an inorganic binder, an organic binder and polyvinyl alcohol in combination. By using them together, the coated surface is less likely to crack even when stress is applied when corrugating the paper, as compared with the case of using only the inorganic binder. This is because if only an inorganic binder is used, it becomes a glass-like coated surface after drying, and cracks are generated by applying a slight stress, and the coated layer is liable to fall off. However, when an organic binder is used in combination, the organic binder acts as an adhesive at a cracked portion, so that the crack does not increase, and as a result, the crack becomes difficult.

The papermaking fibers used in the base paper of the present invention include softwood unbleached kraft pulp (NUKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), and hardwood bleached kraft pulp (LBK).
P), wood pulp such as softwood bleached sulphite pulp (NBSP), thermomechanical pulp (TMP), non-wood pulp such as kozo, mitsumata, straw, hemp, bamboo, straw, linter, bagasse, kenaf and espart, and polyolefin Or a mixture of synthetic fibers such as synthetic pulp, rayon, vinylon, nylon and polyester.

In the production of the base paper, a coloring agent such as a dye or a pigment is added as necessary to the papermaking fiber as described above, and if necessary, various fillers such as clay and calcium carbonate, and a rosin-based material. , Sizing agents such as alkyl ketene dimer,
Dry paper strength enhancers such as starch and polyacrylamide,
Welding paper strength agents such as melamine resin, polyamine / polyamide / epichlorohydrin resin, etc., and auxiliary materials for papermaking such as fixing agent such as sulfuric acid band and polyacrylamide are appropriately used in combination. The paper is made using a paper machine.

When the base paper requires flame retardancy and non-flammability, a flame retardant treatment may be performed during or after papermaking. As a flame retardant, guanidine sulfamate, guanidine phosphate, ammonium sulfamate, a condensed phosphate alkyl ester derivative, guanidine sulfate, ammonium phosphate, ammonium sulfate, calcium chloride, magnesium chloride, borax, boric acid, and the like are dispersed in an aqueous solution or water. Anything that can be used can be used. Another method is to add inorganic powder to 6
There is also a method of blending 5% by weight or more to achieve flame retardancy and non-flammability.

Further, in order to improve the flame retardancy of the surface of the base paper, a coating mainly composed of a substance having water of crystallization such as aluminum hydroxide and magnesium hydroxide may be applied. The flame-retardant paper is a flame-retardant type specified in JIS A 1322 “Test method for flame retardancy of thin building materials”.
Base paper corresponding to either flameproof 1 or 2 can be used.

The types of base paper that can be used in the present invention include:
Art paper, coated paper,
Printing information paper represented by high-quality paper, kraft paper, etc., packaging paper, hybrid paper, cardboard base paper, and the like can be given.

In the present invention, an inorganic binder, an organic binder, a photocatalyst and polyvinyl alcohol are indispensable, but there are auxiliary agents for preparing a coating such as a dispersant, a thickener, a thinner and a pH adjuster. An adsorbent such as activated carbon, silica gel, or zeolite can be appropriately used in combination with an adsorbent such as activated carbon, silica gel, or zeolite in order to preferentially adsorb and remove a specific substance.

[0031]

EXAMPLE 1 A non-combustible base paper (trade name: "TT-120C" manufactured by Tokushu Paper Co., Ltd.) was coated with photocatalytic titanium oxide (trade name: "PC-
101 ", manufactured by Titanium Industry Co., Ltd.), 50 parts by weight, inorganic binder (trade name:" Snowtex C ", manufactured by Nissan Chemical Co., Ltd.), 10 parts by weight, organic binder (trade name:
"Polylac 750", manufactured by Mitsui Toatsu Chemical Industry Co., Ltd.)
5 parts by weight of polyvinyl alcohol (trade name: "PVA1
05 "(manufactured by Kuraray Co., Ltd.), a photocatalyst-containing layer containing 2 parts by weight was provided at 10 g / m ² to obtain a deodorized paper.

EXAMPLE 2 50 parts by weight of titanium oxide photocatalyst ("PC-101"), 30 parts by weight of an inorganic binder ("Snowtex C"), and an organic binder ("TT-120C") A photocatalyst-containing layer containing 20 parts by weight of “Polylac 750”) and 5 parts by weight of polyvinyl alcohol (“PVA105”) was provided at 20 g / m ² to obtain a deodorized paper.

Example 3 Photocatalytic titanium oxide (trade name: "ST-01", manufactured by Ishihara Sangyo Co., Ltd.) was applied to a noncombustible base paper ("TT-120C").
0 parts by weight, inorganic binder (“Snowtex C”)
20 parts by weight of an organic binder (trade name: "Clear
E ", Tsunekazu Chemical Industry Co. preparation) 10 parts by weight of polyvinyl alcohol (" PVA105 ") 3 photocatalyst-containing layer containing parts provided 15 g / m ^2, to obtain a deodorizing paper.

Example 4 Photocatalytic titanium oxide (“ST-2”) was used as a base paper (PPC paper).
1 ") 80 parts by weight, an inorganic binder (" Snowtex C ") 10 parts by weight, an organic binder (" Clear
E ") 10 parts by weight, polyvinyl alcohol (" PVA1
05 ") A photocatalyst-containing layer containing 0.5 parts by weight of 15 g /
m ² to obtain deodorized paper.

EXAMPLE 5 Photocatalytic titanium oxide ("ST-2") was used as base paper (PPC paper).
1)) 60 parts by weight, an inorganic binder (“Snowtex C”) 10 parts by weight, an organic binder (“Clear
E ") 10 parts by weight, polyvinyl alcohol (" PVA1
05 ") 15 g / m ^{2 of the} photocatalyst-containing layer containing 2 parts by weight
To obtain deodorized paper.

Comparative Example 1 A non-combustible base paper ("TT-120C") containing a photocatalyst containing 50 parts by weight of a photocatalytic titanium oxide ("PC-101") and 10 parts by weight of an inorganic binder ("Snowtex C") A layer was provided at 10 g / m ² to obtain deodorized paper.

Comparative Example 2 Photocatalytic titanium oxide ("ST-2") was used as a base paper (PPC paper).
1 ") 80 parts by weight, an organic binder (" Clear
E ") 15 g / m ^{2 of the} photocatalyst-containing layer containing 10 parts by weight
To obtain deodorized paper.

Table 1 shows the evaluation results of the deodorized papers obtained in Examples 1 to 5 and Comparative Examples 1 and 2. The evaluation was performed by the following method.

Evaluation of Deodorizing Performance Evaluation of the deodorizing performance was performed using the apparatus shown in FIG. 1 under the following conditions, and the formaldehyde concentration in the experimental apparatus was measured two hours after the start of light irradiation. Hazardous gas: formaldehyde Initial formaldehyde gas concentration: 200 ppm Sample size: 10 cm × 20 cm UV intensity: 1 mW / cm ² Experimental equipment volume: 30 L Flow rate: 10 L / min

Cracks at the time of bending The obtained deodorized paper was bent at 90 degrees to observe whether cracks occurred.

Coating properties It was evaluated whether repelling, uneven coating, etc. were observed during coating.

[0042] after the light irradiation dusting manufactured by Suga Test Instruments Co. auto fade meter (Model: FAI-
AU-B), powder falling after light irradiation for 6 hours was observed.

[0043]

[Table 1]

From the results in Table 1, the following has been found. (1) In the evaluation of the deodorizing performance, in all the deodorizing papers, formaldehyde was decomposed to the initial concentration of 5 to 10%, and good results were obtained.

(2) In the case of the deodorized paper of Comparative Example 1 using only the inorganic binder, cracking at the time of bending and repelling occurred at the time of coating, and a uniform coating layer could not be obtained.
This is not preferable because it also leads to the fact that the decomposition ability cannot be obtained uniformly.

(3) In the deodorized paper of Comparative Example 2 using only the organic binder, cracking at the time of bending and repelling at the time of coating were not observed, but when the obtained deodorized paper was irradiated with light. Powder fall occurred.

(4) By using an inorganic binder and an organic binder together, a deodorized paper having a uniform coating layer while maintaining the photocatalytic activity, having no repelling, and free from powder dropping by light irradiation was obtained.

Preparation of Paint (Observation of Aggregation) Example 6 Dispersant (trade name: "Aron T-40", Toa Gosei Chemical Industry Co., Ltd.) was added to 120 parts by weight of an inorganic binder ("Snowtex C"). Then, the mixture was stirred for 10 minutes using a sand mill. Next, a photocatalytic titanium oxide (“PC-1”
01 ") and stirred for 40 minutes. Then, 1
20 parts by weight of a 5 wt% polyvinyl alcohol ("PVA105") aqueous solution was added and stirred for 20 minutes. Finally, 15 parts by weight of methyl methacrylate-butadiene latex (“Polylac 750”) was added and stirred for 20 minutes to obtain a photocatalytic coating material.

Example 7 The same chemicals and conditions were used except that the methyl methacrylate-butadiene latex used in Example 6 was changed to an ethylene vinyl acetate emulsion (trade name: "Sumikaflex 500", Sumitomo Chemical Co., Ltd.). A photocatalytic paint was obtained.

Example 8 A photocatalytic paint was obtained using the same chemicals and conditions except that the methyl methacrylate-butadiene latex used in Example 6 was changed to an acrylic resin emulsion ("Clear E").

Comparative Example 3 1.5 parts by weight of a dispersant ("Aron T-40") was added to 120 parts by weight of an inorganic binder ("Snowtex C"), and the mixture was stirred for 10 minutes using a sand mill. Next, 60 parts by weight of titanium oxide photocatalyst ("PC-101") was added and stirred for 40 minutes. Finally, 15 parts by weight of methyl methacrylate-butadiene latex (“Polylac 750”) was added and stirred for 20 minutes to obtain a photocatalytic coating material.

Comparative Example 4 A photocatalytic paint was obtained using the same chemicals and conditions except that the methyl methacrylate-butadiene latex used in Comparative Example 3 was changed to an ethylene vinyl acetate emulsion (“Sumikaflex 500”).

Aggregation at the time of preparing the photocatalytic paint prepared under the conditions of Examples 6 to 8 and Comparative Examples 3 and 4 and the use of the paint were applied to the flame retardant paper used in Example 1 at 20 g / m ² . Table 2 shows the results of observation of aggregates at that time.

[0054]

[Table 2]

From the results in Table 2, the following has been found. (1) By adding polyvinyl alcohol before the addition of the organic binder, many organic binders can be used and aggregation does not occur. As a result, a coating having excellent coating suitability can be prepared, and when coated, a uniform photocatalyst coating layer can be applied to paper.

[0056]

As described above, the photocatalytic deodorizing paper of the present invention has the following remarkable effects. (1) Aggregation does not occur even when an organic binder is used by using polyvinyl alcohol. (2) Powder mixing due to the oxidizing action of the photocatalyst can be prevented by mixing the inorganic binder. (3) By using an organic binder together, the photocatalyst-containing layer exhibits flexibility, and a photocatalyst coating layer free from cracks due to breakage is obtained. (4) By using an organic binder in combination, the coating suitability is improved, so that a uniform coating layer can be obtained. Further, when the coating machine is washed, dirt can be removed more quickly than when the inorganic binder is used alone.

Taking advantage of the above properties, the photocatalytic paint obtained by the present invention can be used not only for paper but also for exteriors, interiors, concrete walls, boards and the like. Further, the photocatalytic deodorizing paper obtained in the present invention can be used for air purifiers, deodorizing machines, wallpaper, antibacterial paper, sterilizing paper, reflectors for lighting, and the like.

[Brief description of the drawings]

FIG. 1 is a test apparatus for evaluating the deodorizing performance of the deodorizing paper of the present invention.

[Explanation of symbols]

 Reference Signs List 1 circulation pump 2 formaldehyde injector 3 formaldehyde generator 4 aqueous formaldehyde solution 5 gas bag 6 reactor 7 photocatalytic deodorizing paper 8 UV lamp

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI D21H 21/14 D21H 1/22 Z 5/22 C

Claims (9)

[Claims] 1. A photocatalytic paint comprising an inorganic binder, a photocatalyst, polyvinyl alcohol and an organic binder. 2. An inorganic binder of 10 to 50% by weight, a photocatalyst of 30 to 80% by weight, a polyvinyl alcohol of 0.1 to 50% by weight.
A photocatalytic paint comprising 30% by weight and 1 to 30% by weight of an organic binder. 3. The photocatalytic paint according to claim 1, wherein the photocatalyst is titanium oxide. 4. A photocatalyst, which is added to an aqueous inorganic binder dispersion.
A method for producing a photocatalytic paint, wherein a polyvinyl alcohol and an organic binder are added sequentially with stirring. 5. A photocatalyst of 30 to 80% by weight, a polyvinyl alcohol of 0.1 to 10% by weight, and an organic binder of 1 to 30% by weight are added to an aqueous dispersion of 10 to 50% by weight of an inorganic binder with stirring. A method for producing a photocatalytic paint. 6. The method for producing a photocatalytic coating according to claim 4, wherein the photocatalyst is titanium oxide. 7. A photocatalytic deodorizing paper characterized in that a photocatalyst-containing layer comprising a photocatalyst, an organic binder, an inorganic binder and polyvinyl alcohol is provided on at least one surface of the base paper. 8. A photocatalyst 30 on at least one surface of the base paper.
5 to 30% by weight of a photocatalyst-containing layer composed of 80 to 80% by weight, an organic binder 1 to 30% by weight, an inorganic binder 10 to 50% by weight, and polyvinyl alcohol 0.1 to 10% by weight.
g / m ^2. Photocatalytic deodorizing paper provided with g / m ² . 9. The photocatalytic deodorizing paper according to claim 7, wherein the photocatalyst is titanium oxide.