JPH11197220A - Polytetrafluoroethylene porous tube containing photocatalyst and stink eliminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a photocatalyst carrier which is porous and cylindrical, and to provide a device for suppressing mixing with gas so as to efficiently eliminate stink by a simple structure where the stink of gas to be processed introduced in to the hollow part of the photocatalyst carrier is eliminated by a photocatalyst excited by a light source arranged in the cylinder and the processed gas is discharged through the pore part of the photocatalyst carrier itself to outside air. SOLUTION: A porous tube 1 contains 1 to 30 pts.wt. of titanium oxide with respect to 100 pts.wt. of polytetrafluoroethylene. A stink eliminator using this porous tube incorporates an ultraviolet ray lamp 2 in the hollow part of the porous tube, and includes a mechanism for generating the flow of processed gas, which is passed through the pore part of a tube wall from a tube inner side to the outer side of the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a porous tube and a deodorizing device. More specifically, the present invention relates to a porous tube made of polytetrafluoroethylene containing titanium oxide having a photocatalytic action, and a deodorizing device using the same.

[0002]

2. Description of the Related Art In order to impart various properties such as antifouling, antibacterial and deodorizing properties to resins and the like, it is known to utilize photochemical reaction of photocatalyst fine particles such as organic semiconductors and metal oxides. With respect to the use of such photocatalyst fine particles, for example, the photochemical reaction efficiency is increased by using photocatalyst fine particles such as titanium oxide and an oxidizing agent (JP-A-5-15447).
No. 3), using photocatalyst fine particles supported on the surface of a substrate (Japanese Patent Application Laid-Open No. Hei 7-265714), and forming a sheet or panel-shaped molding material containing photocatalytic fine particles (Japanese Patent Application Laid-Open No. Hei 6-315614). Is known.
As a photocatalyst, titanium oxide has been widely used because it has superior performance as compared with other photocatalysts.

On the other hand, when the photocatalyst fine particles are used by dispersing them in an organic matrix, there is a problem of deterioration of the organic matrix possibly caused by radicals generated by the photo-semiconductor action of the photocatalyst fine particles. In order to prevent such deterioration of the organic matrix, it has been proposed to use a fluororesin as the matrix (Japanese Patent Laid-Open No. 4-28485).
No. 1).

Some deodorizing apparatuses and harmful organic substance treatment apparatuses using such a photocatalyst carrier have been devised. The main structure of the apparatus is to install a light source inside a cylinder carrying a photocatalyst on the inner surface. In some cases, the gas to be treated is introduced from one side of the cylinder, and the purified gas is discharged from the other side. However, in such a method, on the discharge side, the gas purified by the photocatalyst and the gas that cannot be approached to the vicinity of the photocatalyst and are not purified may be mixed, and the purification efficiency may be reduced. As a countermeasure, install an appropriate stirring device and design a flow path, so that the gas can contact the photocatalyst as much as possible.
Alternatively, methods such as enlarging the contact area of the catalyst are conceivable, but these increase the size and complexity of the apparatus.

[0005]

SUMMARY OF THE INVENTION The present invention provides a porous cylindrical photocatalyst carrier under such circumstances relating to a deodorizing device, and further comprises a cover introduced into the hollow portion of the photocatalyst carrier. It has a simple structure in which the processing gas is deodorized by the photocatalyst excited by the light source disposed in the cylinder, and the processing gas is discharged to the outside air through the pores of the photocatalyst carrier itself. It is an object of the present invention to provide a device for suppressing deodorization and efficiently deodorizing.

[0006]

In order to achieve the above object, a porous tube according to the present invention is characterized in that it is made of polytetrafluoroethylene containing titanium oxide.

[0007] The content ratio of titanium oxide is 100 parts by weight of polytetrafluoroethylene and 1 part by weight of titanium oxide.
It is preferable to contain it by 30 parts by weight. Further, as the titanium oxide, anatase type titanium oxide particles having an average particle diameter of 0.005 to 0.5 μm are preferable.

[0008] In the porous tube of the present invention, an excellent deodorizing effect can be exhibited by using titanium oxide as a photocatalyst, and polytetrafluoroethylene (hereinafter referred to as "PTFE") is used as a matrix. Reduces the degradation of the matrix due to the photocatalyst,
In addition, a porous body having a fine pore structure can be easily produced.

Further, the deodorizing device of the present invention is a deodorizing device using the above-mentioned porous tube, wherein an ultraviolet lamp is built in the hollow portion of the porous tube, and the ultraviolet lamp is directed outward from the inside of the tube. It is characterized by having a mechanism for generating a flow of the processing gas through the pore portion of the tube wall.

In the deodorizing device of the present invention, by adopting such a configuration, the structure can be simplified, the mixing of the processing gas can be suppressed, and the deodorizing can be performed efficiently. Further, it can be expected that the gas flows along the inner wall of the tube due to the resistance of gas permeation through the tube, and the contact time with the catalyst is prolonged. In addition, since the shape is cylindrical, in the case of a rod-shaped light source, the photocatalyst surrounds the light source, so that light can be used efficiently. Furthermore, since the deodorizing device can be stored compactly even when stacked, the introduced gas to be treated is branched and sent to each deodorizing device. Can be raised.

Further, since PTFE itself, which is a matrix of titanium oxide as a photocatalyst, has water repellency, if the pore diameter of the photocatalyst carrier is made small enough to have a predetermined water pressure resistance, the deodorizing apparatus of the present invention can be used with water. Can be used among others. For example, when used for an air diffuser, it is also possible to send purified air into water.

[0012]

Next, the present invention will be described in more detail. The PTFE porous tube containing the photocatalyst of the present invention is produced, for example, as follows. A paste-like mixture obtained by adding titanium oxide particles and an appropriate organic solvent as an extrusion aid to PTFE fine powder is preformed into a cylindrical shape.

As the titanium oxide particles, it is preferable to use an anatase type exhibiting the most excellent photocatalytic activity, and the average particle diameter is generally 0.005 to 0.5 μm.

The proportion of titanium oxide is usually 1 to 30 parts by weight, preferably 5 to 20 parts by weight, based on 100 parts by weight of PTFE fine powder. The extrusion aid is not particularly limited as long as it can wet fine powder and can be completely removed by heating, and naphtha or petroleum hydrocarbon having a boiling point of about 100 to 140 ° C is frequently used.

The preforming is performed at such a pressure that the auxiliary is not squeezed out. After the preforming, the molded product is transferred to a cylinder of an extruder, and the paste is extruded into a tube. This unfired tubular molded product is stretched in the major axis direction or in the major axis direction and the radial direction to be porous. At this time, the extrusion aid may be dried and then stretched, or may be stretched by heating at a temperature lower than the firing temperature of PTFE. As the stretching ratio,
1.5 to 4 times is preferred.

The tube thus made porous is further heated at a temperature not lower than the firing temperature of PTFE,
Fired. At this time, the tube is fixed in the stretching direction so as not to shrink.

The inner diameter, wall thickness, and porosity of the obtained porous tube may be properly used depending on the application, and are not particularly limited.
３3 mm and a porosity of 40-70% are preferred.

The thus obtained PTFE porous tube containing the photocatalytic titanium oxide of the present invention can be used as a photocatalyst carrier of a deodorizing device. As shown in FIG. 1, the deodorizing device has a built-in light source for irradiating ultraviolet light for exciting a photocatalyst in the hollow portion of the porous tube. In FIG. 1, 1 is the photocatalyst carrier,
2 is a light source for generating ultraviolet light, 3 is a support, 4 is a gas supply pipe,
5 indicates a stopper. In order to deodorize the gas to be treated using the deodorizing device shown in FIG. 1, first, the titanium oxide of the photocatalyst carrier 1 is activated by ultraviolet light generated from the light source 2. Here, by introducing the gas to be treated into the hollow portion of the photocatalyst carrier through the gas supply pipe, odor generating components such as aldehydes, hydrogen sulfide, hydrocarbons, and nitrogen compounds are decomposed. The gas thus treated passes through the pores of the porous photocatalyst carrier itself and is discharged out of the photocatalyst carrier.

The light source 2 of the deodorizing device shown in FIG.
As long as it can irradiate ultraviolet rays, examples thereof include a black light, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, and a xenon lamp.

The support 3 of the deodorizing apparatus shown in FIG. 1 is used when the PTFE porous tube containing titanium oxide has a low rigidity such as a thin wall and a large pore portion. The support 3 may be used depending on the application, and may not be used if the strength of the porous tube is not affected. Also,
The structure of the support 3 is not particularly limited as long as it does not completely hinder the flow of gas, and for example, a mesh-like structure can be used.

The plug 5 of the deodorizing apparatus shown in FIG. 1 does not need to be used as long as the end face of the porous tube carrying the titanium oxide opposite to the gas inlet to be treated is welded and sealed.

Further, in the deodorizing device of the present invention, the tubular deodorizing device may be laminated to produce a deodorizing integrated body.

[0023]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 15 parts by weight of anatase type titanium oxide particles (trade name "ST" manufactured by Ishihara Sangyo Co., Ltd.) per 100 parts by weight of PTFE fine powder (trade name "Fluon CD123" manufactured by Asahi ICI Fluoropolymers Co., Ltd.) -01 ", average particle size 0.
007 μm) and 25 parts by weight of naphtha (total 40 parts).
Parts by weight) and mixed uniformly. After this mixture was preformed, the extruder was used to extrude the paste into a tube.
Next, this was air-dried and then dried at 100 ° C. for 30 minutes. This was stretched twice at 250 ° C. in the major axis direction. Thereafter, the tube was fixed and baked at 360 ° C. for 5 minutes. The thus obtained porous tube containing titanium oxide having a photocatalytic action had an inner diameter of 20 mm, a wall thickness of 2 mm, and a porosity of 50%. The porosity was calculated from the following equation. Porosity (%) = [1- (apparent specific gravity of porous body / true specific gravity of porous body)] × 100

With respect to the porous tube containing titanium oxide having a photocatalytic action thus obtained, a decomposition test of malodorous substances was performed as described below. First, a 4 W black light was placed in a hollow portion of a porous tube having a length of 15 cm. One end of the porous tube was plugged and swaged with a wire, and the other end was connected to a gas supply tube provided with a fan. The device was then placed in a 5 liter closed container. After 1000 ppm of acetaldehyde was extracted into the closed container, the black light was turned on, and the fan was rotated to circulate at 200 cc / min. 60 minutes after the start of irradiation, the concentration of acetaldehyde was measured and found to be 100 ppm.

Comparative Example 1 A porous tube was obtained in the same manner as in Example 1, except that only 22 parts by weight of naphtha was mixed with 100 parts by weight of PTFE fine powder. For this, a decomposition test of malodorous substances was performed in the same manner as in Example 1. As a result, acetaldehyde 60 minutes after the start of irradiation was 900 ppm.

From the results of Example 1 and Comparative Example 1, it was found that the PTFE porous tube containing titanium oxide having a photocatalytic action had a deodorizing function.

Comparative Example 2 The outer surface of the tube of the deodorizing apparatus of Example 1 was wrapped and sealed with a film so that air did not leak through the tube wall surface. Next, the stopper was removed, so that the processing gas introduced from the gas supply pipe passed through the hollow portion of the tube and passed through the cylinder. For this, a decomposition test of malodorous substances was performed in the same manner as in Example 1. As a result, acetaldehyde 60 minutes after the start of irradiation was 500 ppm.

According to the results of Example 1 and Comparative Example 2, a porous PTFE tube containing titanium oxide having a photocatalytic action was used in a deodorizing apparatus, and passed through the pore portion of the tube wall from the inside to the outside of the tube. It was found that the deodorizing efficiency was improved by providing a mechanism for generating the flow of the processing gas.

[0030]

As described above, the porous tube containing titanium oxide having a photocatalytic action of the present invention has a deodorizing function, and its structure is simple and deodorized by using it in a deodorizing device. A deodorizing device with good odor efficiency can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a deodorizing device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PTFE porous tube containing titanium oxide 2 Ultraviolet light generation light source 3 Support 4 Gas supply pipe 5 Plug

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C02F 1/32 C08K 3/22 C08K 3/22 C08L 27/18 C08L 27/18 C08J 9/00 CEWA // C08J 9/00 CEW B01D 53/36 J

Claims (4)

[Claims] 1. A porous tube made of polytetrafluoroethylene containing titanium oxide. 2. The porous tube according to claim 1, comprising 1 to 30 parts by weight of titanium oxide based on 100 parts by weight of polytetrafluoroethylene. 3. The titanium oxide has an average particle size of 0.005 to 0.5.
3. The porous tube according to claim 1, wherein the porous tube is 5 μm anatase-type titanium oxide particles. 4. A deodorizing device using the porous tube according to claim 1, wherein an ultraviolet lamp is built in a hollow portion of the porous tube, and the ultraviolet lamp is provided outside the tube. A deodorizing device having a mechanism for generating a flow of a processing gas through a porosity portion of a tube wall directed toward the tubing.