JP2001162172A - Photocatalyst product and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocatalyst product having a high sterilizing and deodorizing effect and high durability of the effect, and to provided its production method. SOLUTION: In the photocatalyst product prepared by fixing a photocatalyst on a substrate with a binder resin, powder having the photocatalytic activity is held on the surface of the binder resin while the surface of the powder is exposed out of the resin. The photocatalyst consists of a photosemiconductor or a mixture thereof and at least one of metal powder and adsorbent. The photocatalyst product is produced by applying the binder resin on the substrate and spraying the photocatalyst powder onto the resin while the applied resin still has cohesive properties so as to fix the photocatalyst with the binder resin to the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocatalyst product which decomposes harmful substances by using an optical semiconductor to perform deodorization and sterilization, and a method for producing the same.

[0002]

2. Description of the Related Art With increasing interest in health and environmental issues, there is an increasing demand not only for the removal of harmful substances on an industrial level, but also for antibacterial and odor removal in everyday life. Many compounds, such as odor components and harmful components,
Ammonia, nitrogen-containing compounds such as amines (eg, trimethylamine, triethylamine, etc.), hydrogen sulfide,
Sulfur-containing compounds such as methyl mercaptan, aldehydes such as formaldehyde and acetaldehyde, formic acid,
Lower fatty acids such as acetic acid and valeric acid are included. In such a living environment, there are various odor components such as acidic odor components such as lower fatty acids, basic components such as nitrogen-containing compounds, sulfur odor components, and neutral odor components such as aldehydes. However, it is generally difficult to remove a plurality of different types of components.

In order to remove these deodorant sources, for example, deodorant fibers having a deodorant carried on the fibers have been proposed. As the deodorant, there are various kinds such as powder and liquid, and in order to carry them on the fibrous material, a method of kneading or a method of coating the surface by impregnation or the like must be adopted. In such a method, the surface of the deodorant is coated with a resin, a binder, or the like, and a sufficient effect cannot be obtained for the added amount.

[0004] Further, deodorants mainly composed of physical adsorption such as activated carbon, silica, and alumina have no ability to decompose odor components, and their adsorption capacities are limited. When the amount of adsorbed odor components reaches a saturated adsorption capacity, deodorants are depleted. Smell ability is lost. In addition, since the odor component adsorbed due to a temperature change or the like is released as it is, it does not make sense to deodorize. Furthermore, even by chemical adsorption that combines with odor component ions, the odor component is not decomposed, so the binding site decreases and disappears with time. become unable.

[0005] Antibacterial agents are hardly effective when their surface is coated with a resin or binder, and the antibacterial agents currently used are elution systems, the effect of which is attenuated with elution, and the effect is sustained. Lack.

In recent years, attention has been paid to a method for removing harmful substances using a photoreactive semiconductor utilizing a photocatalytic action for the above-mentioned deodorants and antibacterial agents. Photoreactive semiconductors have poorer adsorption capacity than the above-mentioned deodorants, and in particular, although their initial harmful substance removal ability is inferior to activated carbon, etc., they decompose odor components, so there is no saturation limit in capacity, There is no self-consumption and degradation for the decomposition and removal of the components, and there is no reduction in performance in principle. In addition, since it can be decomposed regardless of the type of decomposed substance, it has not only great advantages as compared with the deodorant but also has an antibacterial action.

As a deodorant and antibacterial sheet containing such a photoreactive semiconductor, for example, Japanese Patent Application Laid-Open No. 10-256
No. 96 discloses a method of making a paper raw material in which inorganic fine particles having photocatalytic activity are dispersed together with a binder. In this invention, the surface of the photocatalyst is coated with a binder. Deodorization using photoreactive semiconductors,
The decomposition ability of the antimicrobial sheet improves as the contact time between the photoreactive semiconductor and the harmful substance increases, so the effect increases as the contact area between the photoreactive semiconductor and the harmful substance increases and the contact time between the two increases. There is.

Japanese Patent Application Laid-Open No. Hei 10-263412 discloses a method in which a photocatalyst is internally added or coated on paper or nonwoven fabric and the surface is etched to expose the photocatalyst. However, a special etching process is required. This is not a general manufacturing technique because there is a possibility that the strength may be reduced.

[0009]

SUMMARY OF THE INVENTION The present invention provides a photocatalyst product having a high sterilizing and deodorizing effect and a high sustained effect, which is useful for sterilization and deodorizing applications, and a method for producing the same.

[0010]

According to the present invention, there is provided a photocatalyst product comprising a photocatalyst fixed on a substrate by a binder resin, wherein a powder having photocatalytic activity is held on the surface of the binder resin in a state of being exposed outside the resin. And a photocatalyst product characterized in that: More specifically, the present invention relates to the above photocatalyst product, wherein the photocatalyst is an optical semiconductor or a mixture of an optical semiconductor and at least one of a metal powder and an adsorbent. In one embodiment, the present invention relates to the photocatalyst product described above, wherein the photocatalyst and the binder resin on which the photocatalyst is present partially or entirely in the form of dots, bands, or grids on a substrate. Further, the present invention is to apply a binder resin on the substrate, by spraying the photocatalyst powder from the resin while the applied resin has tackiness,
The present invention relates to a method for producing the photocatalyst product, wherein the photocatalyst is fixed on a base material via a binder resin.

In the present invention, since the photocatalyst retains its activity in a state of being exposed from the binder resin, a sufficient chance of contact between the photocatalyst and the harmful substance can be ensured. And it is performed very efficiently. Therefore, the photocatalyst product of the present invention also has a feature that it is not necessary to add a cumbersome and expensive process such as etching, which is a special process, in order to expose the surface of the photocatalyst.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In a photocatalyst product of the present invention, a photocatalyst supported on a substrate via a binder resin is a mixture of an optical semiconductor or an optical semiconductor and at least one of a metal powder and an adsorbent. It is. As the photocatalyst, the above mixture may be used as it is as a powder mixture, or the powder mixture may be granulated to increase the particle size.
When granulated and used, the particle size is preferably 50 to 5
It is 00 μm, more preferably 100 to 200 μm.
The granulation can be performed, for example, by atomizing and drying a slurry dispersed in water. As an optical semiconductor,
TiO ₂ , CdS, CdSe, WO ₃ , Fe ₂ O ₃ , SrT
Powders such as iO ₃ and KNbO ₃ can be given. Particularly preferred is TiO ₂ having an anatase crystal form. These optical semiconductors are powders and may be used as they are, or when importance is placed on handling workability, these powders may be granulated and used. Therefore, the particle diameter of the optical semiconductor is preferably from 0.01 to 500 μm, particularly preferably from 0.3 to 200 μm, in order to secure a large surface area and ensure good workability.

The metal powder exhibits a photocatalytic action in combination with the above-mentioned optical semiconductor, and is preferably a metal such as gold, silver, platinum and copper. A particularly preferred metal is silver. Silver is durable and relatively inexpensive in the presence of water. Furthermore, silver is non-toxic and has a bactericidal property. The powder of these metals preferably has a particle size of 0.01 to 1.0 μm, more preferably 0.05 to 0.1 μm.
Used for m. The mixing ratio of the optical semiconductor powder and the metal powder is such that the metal powder is 1 to 55 with respect to 100 parts by weight of the optical semiconductor.
Parts by weight, preferably 20 to 30 parts by weight.

The adsorbent is for adsorbing and holding malodorous substances and harmful substances, and uses ceramic adsorbent powder such as apatite (apatite), zeolite or sepiolite, and organic adsorbent such as activated carbon. be able to. These may be used as a mixture of two or more types depending on the types of malodor sources or harmful substances present. The particle size of the adsorbent is preferably from 0.001 to 1.0 μm, particularly preferably from 0.01 to 0.1 μm. The mixing ratio of the adsorbent is 1 to 50 parts by weight, preferably 10 to 30 parts by weight, per 100 parts by weight of the optical semiconductor.

The binder resin used for fixing the photocatalyst comprising a mixture of an optical semiconductor and a metal powder and / or an adsorbent powder on a substrate includes acrylic resin, urethane resin, acrylic / urethane resin and the like. Particularly, a self-crosslinking type is preferable. When a superabsorbent resin is used alone or in combination with the above resin as the binder resin, the effect of the photocatalyst can be further enhanced. These binder resins may be used as 100% solids of the resin, or may be in a state of being dispersed in a paste, emulsion, concentrated solution or other liquid. These binder resins may be coated on the entire surface of the substrate or may be partially adhered. What is partial adhesion?
For example, the shape is a dot shape, a band shape, or a lattice shape.

In the case of partial adhesion, since the base material is partially exposed, if various functions are imparted to the base material, these functions can be exhibited in addition to the photocatalytic function. For example, when a nonwoven fabric is used as the base material, the functions that can be imparted to the nonwoven fabric include, for example, (1) mixed spinning of fibers capable of selectively adsorbing a specific odor component, or surface coating or spray application of a treating agent; 2) Activated carbon or the like can be attached to improve the initial deodorizing function; (3) Various antibacterial agents can be used to provide an antibacterial property; (4) Plating of various metals This can provide antibacterial properties and the like. In the case of partial adhesion, the adhesion area is not particularly limited, but in order to make the above-mentioned properties by the substrate effective, the adhesion area is preferably 5 to 40% of the substrate, more preferably 10
20%. If the dot, preferably 0.03～1.2Mm ² the size of individual dots, more preferably 0.0
7 to 0.5 mm ² .

The substrate is not particularly limited, and can be selected according to the intended use, such as a sheet, a block, and a granule. The block-like material includes a plate-like material and a foam block,
The granular material includes a sphere having a size of 1 cm or less, a porous body, a disk, and various other forms. A particularly preferred substrate is a sheet. Since the sheet-shaped material has a large surface area and flexibility, it can easily exhibit its various performances more efficiently and has a wide range of application. Examples of the base material of the sheet-like material include a nonwoven fabric, a knitted fabric, a woven fabric, a net, paper, a plastic film or sheet, and a composite thereof. In particular, the nonwoven fabric is preferably used as a base material used in the product of the present invention because various fiber materials can be used, and a wide variety of forms such as texture and thickness can be selected, and furthermore, it is an economical material. As the nonwoven fabric, any of a fiber-bonded nonwoven fabric, an adhesive-bonded nonwoven fabric, a hydroentangled nonwoven fabric and the like can be used. Further, a nonwoven fabric composited with a filament, a net, a knitted fabric, and a woven fabric can also be used.

The photocatalyst product of the present invention is produced by the following method. The photocatalyst is held on the resin surface by applying a binder resin onto the base material and spraying the photocatalyst from the resin while the applied resin has tackiness. Next, the resin is solidified by cooling or drying to fix the photocatalyst to the resin surface. Thus, a photocatalyst product can be manufactured by fixing a photocatalyst on a base material via a binder resin. Here, the resin is used in a state of being dispersed in a liquid such as 100% resin or paste as described above. When applying 100% resin, it is performed in a molten state. Therefore, "while the applied resin has adhesiveness" means that the resin is in a molten state or the paste or the like is in an undried state.
The application of the binder resin may be performed on the entire surface of the base material or may be partially applied. The partial application refers to, for example, application in a dot shape, a band shape, or a grid shape. For example, application in the form of dots can be performed using a rotary screen.

[0019]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.
And, it will be described in more detail. Example 1 20 parts by weight of silver powder (particle size of 0.05 to 0.1 μm) and hydroxyapatite (particle size of 0.01 to 0. 0) were added to 100 parts by weight of TiO ₂ (particle size of 0.5 to 5.0 μm). .08μm)
10 parts by weight were mixed to prepare a photocatalyst composition as a mixed powder. Next, a polyester non-woven fabric (40 g / m
^2. Acrylic resin is applied to the heat-sealed product in the form of a paste in the form of dots by a rotary screen (adhesion amount: 15 g / m2).
⁽² , 330 dots / square inch) While the acrylic resin paste was tacky, the photocatalyst composition powder was sprayed on the dot surface and allowed to adhere to the acrylic resin paste surface. After removing the powder dropped on the nonwoven fabric other than the acrylic resin portion, the paste was dried at 150 ° C. to completely fix the photocatalyst composition only on the acrylic resin surface, and the photocatalyst sheet 1 having a photocatalyst adhesion amount of 5 g / m ² was obtained. Obtained.

EXAMPLE 2 A superabsorbent resin was added to a polyester nonwoven fabric (basis weight 40 g / m ² , heat-sealed product) previously coated with an ammonia adsorbent (trade name “ODR-M20”; manufactured by Marubishi Yuka Kogyo Co., Ltd.). "AQUALIC" (manufactured by Nippon Shokubai Kagaku Co., Ltd.) is provided in the form of dots in a paste state by a rotary screen (adhesion amount 15 g / m ² , number of dots 330 / square inch). While having the powder, the photocatalyst composition powder having the same composition as in Example 1 was sprayed on the dot surface and allowed to adhere to the acrylic resin paste surface. After removing the powder dropped on the non-woven fabric other than the acrylic resin part, 15
The paste was dried at 0 ° C. to completely fix the photocatalyst composition only on the acrylic resin surface, thereby obtaining a photocatalyst sheet 2 having a photocatalyst adhesion amount of 5 g / m ² .

Example 3 30 parts by weight of silver powder (particle size: 0.05 to 0.1 μm) and hydroxyapatite (particle size: 0.5 to 5.0 μm) were added to 100 parts by weight of TiO ₂ (particle size: 0.5 to 5.0 μm). 01 to 0.08 μm)
15 parts by weight, silica (SiO ₂ ) (particle size: 0.05 to 0.1)
μm) was mixed to prepare a photocatalyst composition powder. Granulate the photocatalyst composition powder, average particle size 100μm
(A particle size distribution of 10 to 120 μm) was prepared. Next, an acrylic resin was coated on the entire surface of one side of the polyester non-woven fabric (having a basis weight of 40 g / m ² , a heat-sealed product) in a paste state (adhesion amount: 20 g / m ² ). The granulated photocatalyst was evenly sprayed on the coating surface and allowed to adhere to the acrylic resin paste surface. After removing excess powder, the paste was dried at 150 ° C. to completely fix the photocatalyst only on the acrylic resin surface, and the photocatalyst sheet 3 having a photocatalyst adhesion amount of 10 g / m ^2.
I got

Comparative Example 1 A photocatalyst composition powder having the same composition as in Example 1 was mixed with 100 parts by weight of an acrylic resin emulsion containing 45% by weight of an acrylic resin. This emulsion is impregnated with a polyester non-woven fabric (having a basis weight of 40 g / m ² , a heat-sealed product).
A photocatalyst sheet 3 having a photocatalyst adhesion amount of 10 g / m ² after drying at 50 ° C. was obtained.

COMPARATIVE EXAMPLE 2 The photocatalyst sheet 3 obtained in Comparative Example 1 was subjected to alkali reduction processing (1
This was immersed in a 5% aqueous sodium hydroxide solution heated to 00 ° C. to reduce the weight by 10%) to obtain a photocatalyst sheet 4 having the photocatalyst composition powder exposed on the surface.

Each photocatalyst product (photocatalyst sheet) obtained in Examples and Comparative Examples was evaluated for antibacterial performance and deodorant performance. The evaluation results are shown in Tables 1 and 2. Evaluation of antibacterial performance and deodorant performance was performed using the following methods. [Antibacterial performance evaluation method] Test bacteria: methicillin-resistant Staphylococcus aureus (MRSA),
E. coli (O-157) and Pseudomonas aeruginosa. Method: Various bacterial liquids were inoculated on the surface of the photocatalyst sheet (the number of inoculated bacteria is described in the table) and left at room temperature (20 to 25 ° C).
During this time, no special light irradiation other than the indoor fluorescent lamp was performed.
The viable cell count 18 hours after the inoculation was measured by a cell count method (based on the test manual of the Textile Sanitary Processing Association).

[Deodorizing performance evaluation method] Test gas (odor generating gas): Ammonia (irritating odor source such as sweat, urine and tobacco odor) Hydrogen sulfide (source of rotting odor of eggs) Methyl mercaptan (such as rotting odor of vegetables) Source) Trimethylamine (Source such as fish spoilage odor) Acetic acid (Source such as vinegar and tobacco odor) Method: Put the above various gases into a Tedlar bag containing a photocatalyst sheet, and after 1 hour, 2 hours, 4 hours and 24 hours The gas concentration in the Tedlar bag was measured by a detector tube.

[0026]

[Table 1]

[0027]

[Table 2]

[Uses of Photocatalyst Product of the Present Invention] The photocatalyst product of the present invention can be used very effectively for the following uses. However, the following is an example, and is not limited to these applications. 1) Food hygiene-related fields (food factories, food and beverage provision facilities, food sales facilities, etc.) Food processing (side dishes, lunch boxes, etc.) For prevention of food poisoning (antibacterial covers, antibacterial towels, etc.) Using antibacterial treatment towels, which are photocatalyst products, after work is completed, food poisoning is prevented by covering tools such as cutting boards with antibacterial treatment covers. In restaurants, etc. Antibacterial tablecloth, antibacterial towel (dry, wet), etc. Use example: In restaurants, etc., a knife is placed directly on the tablecloth, so using the photocatalyst product of the present invention as a tablecloth will improve hygiene. Is improved.

2) Living environment hygiene field (residential environment such as general households and hotels) Humidifiers Humidifiers include heating type, ultrasonic type and vaporization type.
Both types require water for humidification, and bacteria grow in the water with the passage of time. As a result, bacteria and the like are scattered together with the humidification in the room. By using the photocatalyst product of the present invention around water in a humidifier, bacteria can be sterilized and suppressed, and the indoor sanitary condition can be kept good. Toiletries (antibacterial deodorant toilet seat cover, antibacterial deodorant towel, etc.) By using the antibacterial deodorant product, which is a photocatalyst product of the present invention, in toilets that are particularly concerned about hygiene, it is possible to improve hygiene and to improve odor Can also be removed or reduced. By applying an adhesive treatment to one side, it can be stuck or peeled like a tape.

3) Leisure (outdoor, etc.) Related Leisure sheet (field sheet), tent sheet, etc. Many of these sheets have a structure of surface (cotton) / batting / waterproof sheet, and this surface is used in the present invention. By using the photocatalyst sheet described above, the more the sunlight shines outdoors, the more antibacterial action can be performed, and a hygienic sheet can be obtained. Tablecloths, hand towels, etc. Antibacterial is possible only by exposure to light, so the sanitary function works effectively.

4) Miscellaneous Goods, Other Automobile Supplies (Trunk Seat, Seat Cover, etc.) It is possible to decompose and remove odors such as indoor tobacco odors. The effect is increased by sunlight.

Other fields in which the photocatalyst product of the present invention is expected to be used as an antibacterial product are shown in Tables 3 and 4.

[Table 3]

[0033]

[Table 4]

[0034]

According to the photocatalyst product of the present invention, excellent effects such as sterilization and deodorization can be obtained semi-permanently by the adsorbing action of the adsorbing material and the photocatalytic action of the photocatalyst powder and the metal powder without being attenuated over time. Can be sustained. Further, according to the production method of the present invention, various materials (non-woven fabric, woven fabric, paper, etc.) are sterilized in various states (areas and shapes),
A deodorizing effect can be provided.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B01D 53/36 HF term (Reference) 4C080 AA07 BB02 BB05 CC01 HH05 JJ05 JJ06 KK08 MM01 MM02 MM04 MM07 4D048 AA22 AA30 AB03 BA06Y BA07Y BA34Y BA44Y BB02 BB03 BB06 BB07 BB08 EA01 4F100 AA04 AA21 AB01A AB24 AK24 AK41 AS00A AT00B BA02 DC15A DC22A DC30A DE01 DE01A DG10B DG12B DG13B DG15B EH46 EH76 JC00 JG10A JL08A JN30A 4G069 AA03 AA08 BA02B BA04B BA22A BA22B BA48A BB02B BC32B CA01 CA11 CA17 DA06 EA09 EA13 FA06

Claims (6)

[Claims] 1. A photocatalyst product comprising a photocatalyst fixed on a base material by a binder resin, wherein the photocatalyst is held on the surface of the binder resin in a state where the photocatalyst is exposed outside the resin. 2. The photocatalyst product according to claim 1, wherein the photocatalyst is an optical semiconductor or a mixture of the optical semiconductor and at least one of a metal powder and an adsorbent. 3. The base material is a nonwoven fabric, a knitted fabric, a woven fabric, a net,
3. The photocatalyst product according to claim 2, wherein the photocatalyst product is a sheet material selected from paper, a plastic film or sheet, or a composite thereof. 4. The photocatalyst according to claim 1, wherein the photocatalyst and the binder resin on which the photocatalyst is present partially or entirely in a dot shape, a band shape, or a lattice shape on the substrate. Product. 5. A photocatalyst is fixed on a base material via a binder resin by coating a binder resin on the base material and spraying a photocatalyst powder from the resin while the applied resin has tackiness. A method for producing a photocatalyst product according to claim 1. 6. The production method according to claim 5, wherein the binder resin is partially applied on the base material in a dot shape, a band shape or a grid shape, or is applied entirely.