JP2006028688A - Method for producing photocatalyst body-carrying product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of producing a photocatalyst body-carrying product exhibiting high initial performance. <P>SOLUTION: The method for producing the photocatalyst body-carrying product comprises carrying the photocatalyst body on a support by a binder and bringing the photocatalytic body into contact with an organic solvent or water. The binder is e.g. an emulsion type binder such as an acrylic emulsion, vinyl acetate emulsion, an ethylene-vinyl acetate emulsion, a polyurethane emulsion, a polyester emulsion, a polyolefin emulsion, a silane-based resin emulsion or a fluororesin emulsion. The support is a fiber or a paper. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a method for producing a photocatalyst-supported product, and more particularly to a method for producing a product in which a photocatalyst is supported on a carrier by a binder.

A photocatalyst-supported product in which a photocatalyst is supported on a carrier such as fiber or paper is known as an article exhibiting a deodorizing action, an antibacterial action and the like. A binder can be used for loading.
However, when supported by a binder, there is a problem that the initial activity of the supported photocatalyst is low.

WO98 / 15600 JP 2003-105262 A JP 9-328336 A JP 2004-59686 A WO01 / 023483 pamphlet JP 11-209691 A JP 2001-72419 A JP 2001-190953 A JP 2001-316116 A JP 2001-322816 A JP 2001-29749 A JP 2002-97019 A WO01 / 10552 pamphlet JP 2001-212457 A JP 2002-239395 A WO03 / 080244 Pamphlet WO02 / 053501 pamphlet JP 2001-278625 A JP 2001-278626 A JP 2001-278627 A JP 2001-302241 A JP 2001-335321 A JP 2001-354422 A JP 2002-29750 A JP 2002-47012 A JP 2002-60221 A JP 2002-193618 A JP 2002-249319 A "Titanium oxide" written by Manabu Seino, published by Gihodo Chemistry Letters, Vol. 32, no. 2, P.M. 196-197 (2003) Chemistry Letters, Vol. 32, no. 4, P.I. 364-365 (2003) Chemistry Letters, Vol. 32, no. 8, P.I. 772-773 (2003) Angelwandte Chemie, International Edition, 42, p. 4908-4911 (2003)

Therefore, as a result of intensive investigations to develop a method capable of producing a photocatalyst-supported product exhibiting high initial performance, the present inventor initially supported the photocatalyst by a binder and then contacted it with an organic solvent or water. The inventors have found that a product having excellent activity can be obtained, and have reached the present invention.

That is, the present invention provides a method for producing a photocatalyst-supported product, wherein the photocatalyst is supported on a carrier with a binder and then contacted with an organic solvent or water.

According to the production method of the present invention, a photocatalyst-supported product having a high initial activity can be easily produced.

The photocatalyst used in the production method of the present invention is, for example, a substance that exhibits photocatalytic activity by irradiation with ultraviolet rays or visible light, and specifically shows a crystal structure obtained by X-ray diffraction, and includes metal elements and oxygen. , Powders of compounds with nitrogen, sulfur and fluorine. For example, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, Ag, Au, Zn One or more of metal elements such as Cd, Ga, In, Tl, Ge, Sn, Pb, Bi, La, Ce, nitride, sulfide, oxynitride, oxysulfide, Nitrogen fluoride, oxyfluoride, oxynitride fluoride and the like can be mentioned. Among these, oxides of Ti, W or Nb are preferable, and anatase type titanium oxide, brookite type titanium oxide, rutile type titanium oxide [TiO ₂ ] and the like are particularly preferable.

Titanium oxide that can be used as a photocatalyst can be produced, for example, by the sulfuric acid method or the chlorine method described in Non-Patent Document 1 ["Titanium oxide" (Kyoto Seino, Gihodo Publishing). Further, it can be produced by a method of reacting a titanium compound with a base, adding ammonia to the product, aging, solid-liquid separation, and then baking the solid content. In this method, examples of titanium compounds include titanium trichloride [TiCl ₃ ], titanium tetrachloride [TiCl ₄ ], titanium sulfate [Ti (SO ₄ ) ₂ .mH ₂ O, 0 ≦ m ≦ 20], titanium oxysulfate [ TiOSO ₄ · nH ₂ O, 0 ≦ n ≦ 20], titanium oxychloride [TiOCl ₂ ] can be used. As the base to be reacted with the titanium compound, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonia, hydrazine, hydroxylamine, monoethanolamine, acyclic amine compound, or cyclic aliphatic amine compound should be used. Can do. The reaction between the titanium compound and the base is carried out at a pH of 2 or more, preferably 3 or more, and 7 or less, preferably pH 5 or less. The temperature at that time is usually 90 ° C. or less, preferably 70 ° C. or less, more preferably 55 ° C. It is as follows. Furthermore, in order to improve the grindability of the produced titanium oxide, the reaction between the titanium compound and the base may be performed in the presence of hydrogen peroxide. For aging, for example, a product added with ammonia is stirred at a temperature range of 0 ° C. or higher, preferably 10 ° C. or higher, 110 ° C. or lower, preferably 80 ° C. or lower, more preferably 55 ° C. or lower. It can be carried out by a method of holding for at least 10 minutes, preferably at least 10 minutes, and within 10 hours, preferably within 2 hours. The total amount of ammonia used for the reaction and ripening is preferably an amount exceeding the stoichiometric amount of the base required to convert the titanium compound to titanium hydroxide in the presence of water, for example, 1.1 mol times or more It is preferable that The larger the amount of the base, the easier it is to obtain a coating liquid capable of forming a film exhibiting high photocatalytic activity by irradiation with visible light. For example, 1.5 mole times or more is more preferable. On the other hand, even if the amount of the base is too large, an effect commensurate with the amount cannot be obtained, so 20 mol times or less, further 10 mol times or less is appropriate. Solid-liquid separation of the aged product can be performed by pressure filtration, vacuum filtration, centrifugation, decantation, or the like. In the solid-liquid separation, it is preferable to perform an operation for washing the obtained solid content. The solid content separated by solid-liquid separation or the solid content subjected to arbitrary washing is usually 250 ° C or higher, preferably 270 ° C or higher, and 600 ° C or lower, using an airflow firing furnace, a tunnel furnace, a rotary furnace, or the like. Preferably, it can be carried out under a temperature condition of 500 ° C. or lower, more preferably 400 ° C. or lower. The time at this time varies depending on the firing temperature and the type of firing apparatus and is not unambiguous, but is usually 10 minutes or longer, preferably 30 minutes or longer, and 30 hours or shorter, preferably 5 hours or shorter. If necessary, the titanium oxide obtained by firing includes a compound showing solid acidity such as an oxide or hydroxide of tungsten, niobium, iron, nickel or lanthanum, an oxide or hydroxide of cerium, etc. A compound showing solid basicity such as, or a metal compound that absorbs visible light such as indium oxide or bismuth oxide may be supported.

Tungsten oxide [WO ₃ ] that can be used as a photocatalyst can be produced by a method of firing a tungsten compound such as ammonium metatungstate. Firing may be performed under conditions that allow the tungsten compound to be converted to tungsten oxide, and can be performed in air at 250 ° C. to 600 ° C., for example.

Niobium oxide [Nb ₂ O ₅ ] that can be used as a photocatalyst can be produced by a method of firing a niobium compound such as niobium hydrogen oxalate, for example. Niobium alkoxides such as niobium pentaethoxide and niobium pentaisopropoxide are dissolved in alcohol, and an acidic solution composed of an inorganic acid and alcohol is mixed with this solution and concentrated to obtain a viscous solution, which is fired. It can also be obtained by

When these oxides other than titanium oxide, tungsten oxide, and niobium oxide are used as the photocatalyst, the oxide reacts with, for example, a metal chloride, sulfate, oxysulfate, or oxychloride that constitutes ceramics and ammonia. In addition, the product can be prepared by a method of calcining in air or a method of calcining an ammonium salt of a metal constituting the photocatalyst in the air.

As the photocatalyst used in the present invention, in addition to the above,
(A) The average half-width of the first and second titanium peaks when the half-width of the titanium peak between 458 eV and 460 eV of titanium oxide is measured four times by X-ray photoelectron spectroscopy. The value is A, the average value of the half-value widths of the third and fourth titanium peaks is B, and from the half-value widths A and B, the following formula (I)
X = B / A (I)
And the integrated value of the absorbance of the spectrum at a wavelength of 220 nm to 800 nm when the index X is 0.97 or less and the ultraviolet-visible diffuse reflection spectrum is measured, and the absorbance of the spectrum at a wavelength of 400 nm to 800 nm The integral value of D is defined as D, and from the integral values C and D, the following formula (II)
Y = D / C (II)
Titanium oxide whose index Y is 0.14 or more (Patent Document 7: JP-A-2001-72419),

(B) The electron spin resonance spectrum has three or more peaks between g values of 1.930 to 2.030, and the peak among these peaks has a g value of 1.990 to 2.020. Titanium oxide (Patent Document 8: Japanese Patent Laid-Open No. 2001-190953) existing between

(C) The spin concentration X determined from the electron spin resonance spectrum measured after irradiation with visible light is 1.50 × 10 ¹⁶ spin / g or more, and the spin concentration X determined from the electron spin resonance spectrum measured after irradiation with visible light , Titanium oxide having a ratio (X / Y) with spin concentration Y determined from an electron spin resonance spectrum measured before irradiation with visible light exceeding 1.00 (Patent Document 9: JP 2001-316116 A),

(D) Analyzed 8 times by X-ray photoelectron spectroscopy, and for the electronic state of titanium, the integrated spectrum of the first and second analysis and the integrated spectrum of the seventh and eighth analysis were obtained, A peak at a binding energy of 458 eV to 460 eV is obtained, and the half width of the peak in the integrated spectrum of the first and second analysis is A1, and the half width of the peak in the integrated spectrum of the seventh and eighth analysis is When B1, the following formula (III)
X1 = B1 / A1 (III)
The index X1 calculated by the equation (1) is 0.9 or less, and an ultraviolet-visible diffuse reflection spectrum is measured. The integrated value of absorbance at wavelengths of 250 nm to 550 nm is defined as C1, and the integrated value of absorbance at wavelengths of 400 nm to 550 nm is defined as D1. The following formula (IV)
Y1 = D1 / C1 (IV)
Titanium oxide (Patent Document 10: JP-A-2001-322816) having an index Y1 calculated by

(E) When the X-ray photoelectron spectroscopy is used for analysis eight times, and the integrated spectrum of the first and second analyzes and the integrated spectrum of the seventh and eighth analyzes are obtained for the electronic state of titanium, The position of at least one peak in the integrated spectrum of the second analysis is in the binding energy 459 to 460 eV, and the position of at least one peak in the integrated spectrum of the seventh and eighth analysis is in the binding energy 458 to 459 eV. Titanium oxide having a metal content of 0.005 to 3.0 mol% in terms of element with respect to titanium in titanium oxide (Patent Document 11: JP 2001-29749 A),

(F) For a mass chromatogram obtained by a thermobalance mass spectrometry simultaneous measurement method, titanium oxide having a desorption peak of a component having a ratio m / e of mass number m to ion charge number e of 28 at 600 ° C. or higher, Alternatively, in the mass chromatogram obtained by the thermobalance mass spectrometry simultaneous measurement method, the desorption peak of the component having a ratio m / e of the mass number m and the ion charge number e is 28 is 600 ° C. or more and 950 ° C. or less, Titanium oxide having a desorption peak of a component having an m / e of 14 at 600 ° C. or more and 950 ° C. or less (Patent Document 12: JP-A-2002-97019),

(G) Titanium oxide in which part of the oxygen sites of the titanium oxide crystal is replaced with nitrogen atoms, titanium oxide doped with nitrogen atoms between the lattices of the titanium oxide crystal, and titanium oxide crystal grain boundaries doped with nitrogen atoms (Patent Document 13: WO01 / 10552 pamphlet),

(H) a titanium oxide having stable oxygen defects, a signal having a g value of 2.003 to 2.004 is observed in an electron spin resonance spectrum measured in vacuum at 77K and in the dark, and The signal having a g value of 2.003 to 2.004 is a titanium oxide having a higher signal intensity when measured under irradiation with light of at least 420 to 600 nm at 77K in vacuum than in the case of measurement under darkness. Patent Document 14: Japanese Patent Laid-Open No. 2001-212457),

(I) PtCl ₂ , PtCl ₄ , PtCl ₂ · 2H ₂ O, H ₂ [Pt (OH) ₂ Cl ₄ ] · nH ₂ O, PtBr ₂ , PtBr ₂ , PtI ₂ , PtI ₄ , PtF ₄ , chloride on the surface Spindle-shaped titanium oxide having a halogenated platinum compound such as platinic acid, chloroplatinate, bromoplatinum complex, or iodoplatinate (Patent Document 15: JP-A-2002-239395),

(J) titanium oxide (Patent Document 16: WO03 / 080244 pamphlet) containing a metal halide (such as TiCl4) and a metal complex (such as a heteropolyacid and an isopolyacid) on the surface;

(K) Titanium oxide containing alkaline earth metal, transition metal and Al on the surface (Patent Document 17: WO02 / 053501 pamphlet),

(L) Titanium oxide in which nitrogen and fluorine are substituted at the oxygen position (Non-Patent Document 2: Chemistry Letters, Vol. 32, No. 2, P.196-197 (2003)),

(M) Titanium oxide in which sulfur is substituted at the Ti position (Non-patent Document 3: Chemistry Letters, Vol. 32, No. 4, P. 364-365 (2003)),

(N) Titanium oxide doped with carbon (Non-patent document 4: Chemistry Letters, Vol. 32, No. 8, P. 772-773 (2003), Non-patent document 5: Angelwandte Chemie, Internationaol Edition, 42, P. 4908-4911 (2003)).

(O) In addition, Patent Document 18 (Japanese Patent Laid-Open No. 2001-278625), Patent Document 19 (Japanese Patent Laid-Open No. 2001-278626), Patent Document 20 (Japanese Patent Laid-Open No. 2001-278627), and Patent Document 21 (Japanese Patent Laid-Open No. 2001). -302241), Patent Document 22 (Japanese Patent Laid-Open No. 2001-335321), Patent Document 23 (Japanese Patent Laid-Open No. 2001-354422), Patent Document 4 (Japanese Patent Laid-Open No. 2002-29750), and Patent Document 25 (special Japanese Patent Application Laid-Open No. 2002-29750). JP 2002-47012), Patent Document 26 (JP 2002-60221), Patent Document 27 (JP 2002-193618), Patent Document 28 (JP 2002-249319), and the like. Examples thereof include titanium oxide obtained by the method.
These photocatalysts are used alone or in combination of two or more.

A commercially available photocatalyst can also be used. As commercially available photocatalysts, for example, “TPS-201”, “TPS-4110”, “TSS-4210” from Sumitomo Chemical Co., Ltd., “P-25” from Degussa Corporation, from Ishihara Sangyo Co., Ltd. “ST-01”, “ST-21”, “ST-31”, “ST-41”, “ST-30L”, “STS-01”, “STS-02”, “STS-02”, “STS” Commercially available as “-21”, “STS-230”, and “STS240”.

Examples of the carrier include fibers and paper. Specific examples of the fibers include curtains, carpets, duvet covers, sheets, clothing, car seats (car chairs), air conditioners, air purifier filters, masks, and the like. It may also be unemployed cloth. Examples of paper include wallpaper and vacuum cleaner dust bags.

As the binder used for supporting the photocatalyst on a carrier, for example, an emulsion type binder is used. Specifically, for example, an acrylic ester unit is a main component, and this is a co-polymer of methacrylic ester, styrene, silicone, and the like. Acrylic emulsion, such as polymer
A vinyl acetate emulsion comprising a polymer mainly composed of vinyl acetate units;
An ethylene-vinyl acetate emulsion mainly composed of ethylene units and vinyl acetate units;
Polyurethane emulsion based on polyurethane,
Polyester emulsion based on polyester,
Polyolefin emulsion mainly composed of polyethylene and polypropylene,
Silicone and silane resin emulsions based on silane resins,
Examples thereof include a binder made of a fluororesin emulsion mainly composed of a fluororesin. The particle size of the emulsion type binder is usually about 0.1 to 1 μm, preferably about 0.2 μm or less.

The usage-amount of a binder is 0.01 mass times-1 mass times normally with respect to a photocatalyst body in conversion of solid content, Preferably it is about 0.02 mass times-0.5 mass times.

The binder is usually used in a state dispersed in a solvent such as water. The amount of water used is usually about 1 to 10 times, preferably about 1 to 3 times the solid content of the binder.

In order to support the photocatalyst on a carrier, for example, the photocatalyst may be mixed with an emulsion binder and water and applied to the carrier. Since the emulsion type binder is usually obtained in a state of being dispersed in water, the emulsion binder in a state of being dispersed in water may be mixed with the optical medium. The coating method is not particularly limited, and is appropriately selected depending on the type and shape of the carrier used. For example, brush coating method, dip coating method, flow coating method, spin coating method, spray coating method, bar coating method, etc. It can apply | coat by the usual method.

After coating, the photocatalyst is supported on the carrier by the emulsion type binder by volatilizing the solvent.

In the production method of the present invention, after supporting the photocatalyst, it is brought into contact with an organic solvent or water. Examples of the organic solvent include alcohols such as ethanol and isopropanol, ethers such as tetrahydrofuran and diethyl ether, aromatic hydrocarbons such as benzene and toluene, hydrocarbons such as hexane, nitriles such as acetonitrile, and acetone. Examples thereof include ketones and the like, which are appropriately selected depending on the acrylic binder and carrier used so that the acrylic binder and carrier are not dissolved or altered. An organic solvent may be used individually, respectively, and 2 or more types may be mixed and used for it. Moreover, when using an organic solvent soluble in water, it may be used by mixing with water.

For contacting, for example, the supported carrier may be immersed in an organic solvent or water. The contact temperature at the time of contact is usually about 0 ° C to 100 ° C, preferably 40 ° C to 60 ° C. The contact time is usually about 1 minute to 1 hour.

The desired photocatalyst-supported product can be obtained by drying after contact.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by this Example.

Example 1
[Supporting photocatalyst]
Photocatalyst commercially available as a sol dispersed in water [“TSS-4210”, manufactured by Sumitomo Chemical Co., Ltd., titanium oxide powder] and acrylic emulsion [“Light Epoch AX-45”, manufactured by Kyoeisha Chemical Co., Ltd. ] And diluted with water to obtain a mixed solution having a titanium oxide powder concentration of 1.8 wt% and an acrylic emulsion solid content concentration of 0.3 mass%. A polyester cloth (weighing 194 g / m ² ) is immersed in this mixed solution, squeezed with a mangle, dried at 110 ° C. for 5 minutes, and further heat treated at 180 ° C. for 1 minute to carry titanium oxide powder with an acrylic emulsion. I let you. The supported amount of titanium oxide powder was 3.84 g / m ² , and the supported amount of acrylic emulsion was 0.64 g / m ² .

[Contact with organic solvent]
The polyester cloth after supporting the titanium oxide powder was cut into 10 cm × 10 cm, and immersed in 50 ° C. isopropanol (500 mL) for 30 minutes for contact. Thereafter, it was washed with isopropanol at room temperature (about 25 ° C.), further washed with pure water at room temperature, and then dried at 110 ° C. for 10 minutes to obtain a product in which the photocatalyst was supported on a polyester cloth.

[Evaluation of photocatalyst-supported products]
The product obtained above was placed in a Tedlar bag (internal volume 1 L), pure nitrogen gas and pure oxygen gas were mixed at a partial pressure ratio of 8: 2 under atmospheric pressure, and 600 mL of a mixed gas adjusted to a relative humidity of 50% and a concentration (Partial pressure ratio) 3% of nitrogen gas containing acetaldehyde at 1% was sealed, and illuminated by two 18 W fluorescent lamps [“lifeline”, straight tube, white (glow starter type) 20 type] from the top of the Tedlar back. The illuminance at this time was 18000 Lx. When the concentration of acetaldehyde in the Tedlar bag was measured with a gas chromatograph over time, the time required to decompose acetaldehyde to a concentration of 0 ppm was 20 hours.

Example 2
In the same manner as in Example 1, after a titanium oxide powder was supported on a polyester cloth by an acrylic emulsion, it was immersed in pure water (30 L) at 50 ° C. for 30 minutes for contact. Thereafter, it was washed twice with pure water at room temperature (about 25 ° C.) and dried at 110 ° C. for 10 minutes to obtain a product in which the photocatalyst was supported on a polyester cloth.

When the product obtained above was evaluated in the same manner as in Example 1, the time required to decompose acetaldehyde to a concentration of 0 ppm was 45 hours.

Comparative Example 1
By operating in the same manner as in Example 1 and supporting titanium oxide powder on a polyester cloth with an acrylic emulsion, and evaluating it as in Example 1, the time required to decompose acetaldehyde to a concentration of 0 ppm was 65 hours. Met.

Claims (4)

A method for producing a photocatalyst-supported product, wherein the photocatalyst is supported on a carrier with a binder and then contacted with an organic solvent or water. The production method according to claim 1, wherein the binder is an emulsion type binder. The production method according to claim 2, wherein the emulsion type binder is a binder comprising an acrylic emulsion, a vinyl acetate emulsion, an ethylene-vinyl acetate emulsion, a polyurethane emulsion, a polyester emulsion, a polyolefin emulsion, a silane resin emulsion, or a fluororesin emulsion. The production method according to claim 1, wherein the carrier is fiber or paper.