JPH04323007A - Adsorbent - Google Patents

Abstract

PURPOSE:To make it possible to display high adsorbing characteristics even under the condition that adsorbent is solidified by resin by a method wherein the adsorbent having adsorptive action to injurious material and malodor is produced out of polytetrafluoroethylene resin formed body containing adsorbent powder, the particle diameter of which is specified. CONSTITUTION:As the adsorbent concerned, powder and granular active carbon, active carbon fiber or the like, various porous materials such as silica gel, alumina, magnesia, zeolite and the like and the above-mentioned materials surface-treated with acid or alkali are employed. The particle diameter of the adsorbent is prepared to be 0.5mm or less. By adding the a sorbent powder to PTFE resin (polytetrafluoroethylene resin) formed body, the desired adsorbent is obtained. Its manufacturing is performed by mixing the adsorbent with PTFE dispersions and co-coagulating them or by forming paste-like mixture prepared by mixing them in the presence of organic solvent such as naphtha or the like in the required shape. The formed body is turned into sheet, tube or the like in the fashion of stretched matter or sintered matter.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorbent material that has an adsorption effect on harmful substances and bad odors.

0002

[Prior art and its problems] Powdered adsorbents are encapsulated, mixed with resin to form molded products, and fixed onto fabrics using adhesives to make them easier to handle. It is known that
JP-A No. 2-2731513, etc.). However, the adsorbent materials obtained in this way have not yet been satisfactory. For example, the method of encapsulation has the problem that it is difficult to encapsulate and is expensive, and the method of immobilizing it on the fabric with an adhesive has no durability and is difficult to encapsulate. There is a problem that the agent easily falls off due to the action of mechanical force. Conventional products made by mixing and molding adsorbents and plastic materials include polyolefin, polymethyl methacrylate,
Polyvinyl alcohol, ABS resin, etc. are used. However, this conventional product had no or very little air permeability, and the surface of the adsorbent was completely covered with resin, resulting in extremely poor adsorption efficiency. Furthermore, this conventional product had the disadvantage that the adsorbent could not be reactivated.

0003

SUMMARY OF THE INVENTION An object of the present invention is to provide an adsorbent material that has high adsorption performance even though the adsorbent is firmly fixed to the resin.

0004

[Means for Solving the Problems] The present inventors have conducted extensive research to solve the above problems, and as a result, have completed the present invention.

That is, according to the present invention, there is provided an adsorbent material made of a polytetrafluoroethylene resin molding containing adsorbent powder with a particle size of 0.5 mm or less.

In the present invention, polytetrafluoroethylene resin (hereinafter also simply referred to as PTFE resin) is used to immobilize the adsorbent. PTFE resin has a larger molecular weight than other resins, does not contain low molecular weight impurities such as monomers and oligomers, and has a high heat resistance temperature of 260°C, allowing for high mixing and molding temperatures. Even when PTFE resin and adsorbent are mixed and molded, the resulting adsorbent material does not lose its activity and has sufficient activity to be used as is. In addition, even if it has been deactivated, it can be easily activated by heating or steaming treatment. Further, since PTFE resin has high gas permeability and low surface energy, even if it is mixed and molded with an adsorbent, the resin only covers the adsorbent in a loose state. As a result, a micropore structure is generated at the interface between the adsorbent and the resin, through which gas can easily permeate, and the adsorption rate of the adsorbent is significantly improved. Moreover, the micropore structure gives flexibility to the molded product, and even if the adsorbent is mixed with the resin at a high density, the resulting molded product is highly flexible.

As the adsorbent, conventionally known adsorbents can be used, including adsorbents having physical properties and chemical adsorption properties. Such adsorbents include, for example, powdery activated carbon,
In addition to activated carbon fiber, various porous materials such as silica gel, alumina, silica alumina, magnesia, zeolite, and sepiolite; these porous materials are surface-treated with acid or alkali, or increase the adsorption rate for specific gas components. Examples include those to which specific organic or inorganic compound components have been adsorbed in advance. The size of the adsorbent is a particle size of 5 mm or less, preferably 0.1 mm or less. When the particle size of the adsorbent is larger than 0.5 mm, the mixing and dispersion in the resin tends to become uneven, and the pore structure formed at the interface between the adsorbent and the resin becomes coarse.
Immobilization of adsorbent becomes insufficient. The mixing ratio of adsorbent to PTFE resin is 10 to 90% by weight in the entire molded body.
However, considering the adsorption performance and the bonding strength of the adsorbent to the resin, it is preferable that the content be 25 to 75% by weight.

To obtain the adsorbent material of the present invention, the adsorbent is mixed with the PTFE dispersion and co-coagulated or mixed in the presence of an organic solvent such as naphtha to obtain a paste-like mixture. , mold the resulting mixture into the desired shape. Molding methods include injection molding, extrusion molding, calendar molding,
Various forming methods such as rolling may be employed. The shape of the molded body can be various shapes such as sheet, plate, cylinder, container, and fiber. Moreover, the molded body can be a stretched product or a sintered product. The stretched product can be obtained by stretching a sheet-like or fibrous molded product in a softened state. Sintered products, molded products, 330 to 40
It can be obtained by heating to 0°C, preferably 340 to 370°C. Stretched products and sintered products have more developed micropore structures and have high gas permeability. The sheet-like adsorbent material of the present invention was laminated and adhered onto a fabric such as a woven fabric or a non-woven fabric. It can also be handled as a cloth-like material.

[0009]

Effects of the Invention: Although the adsorbent material of the present invention is a molded mixture with a resin, it is porous as a whole, so it has high gas permeability and moisture permeability, and has a high rate of adsorption of harmful substances. A major feature of the harmful substances is that their adsorption ability can be reactivated by heating them, which have been deactivated by adsorption. Moreover, since the adsorbent material of the present invention is highly flexible, it is extremely easy to handle. The adsorbent material of the present invention can be advantageously used as an adsorbent to remove harmful substances and bad odors from the air or atmosphere, and can also be used as an adsorbent for pollutants dissolved in liquid. can. Furthermore, the adsorbent material of the present invention can also be used as a filter that also has the function of adsorbing pollutants. Furthermore, the adsorbent material of the present invention can also be used as an adsorbent protective clothing material that adsorbs and removes bad odors and harmful gases.

0010

EXAMPLES Next, the present invention will be explained in more detail with reference to examples.

Example 1 Crushed coconut shell activated carbon with a particle size of 50 μm and PTFE resin were dry-blended in a predetermined ratio, and naphtha was added as an extrusion aid and aged, which was then extruded to form a paste film. It was rolled with a rolling roll and formed into a sheet with a thickness of 0.5 mm. Next, the formed sheet-like material is
The extrusion aid was removed by drying at 00°C for 20 minutes. Part of it was used as a test sample as it was, and the other part was fixed to a frame to prevent shrinkage and heated to 355°C.
The PTFE resin was heat-treated for 10 minutes to bake the PTFE resin, and a test sample of the baked product was prepared.

Example 2 The sheet material obtained in Example 1 from which the extrusion aid had been removed was
It was stretched 1.5 times in both the vertical and horizontal directions in an atmosphere at 0°C. A part of this drawn product was used as a second sample as it was, and the other part was heat treated in the same manner as in Example 1 to make a fired product test sample.

Comparative Example 1 The same coconut shell activated carbon and polyethylene powder used in Example 1 were mixed in a weight ratio of 1:1, extruded in an extruder at 150°C into a rod shape, and pelletized to produce activated carbon. A pellet in which polyethylene and polyethylene were well mixed was obtained. This pellet is molded using a hot press at 120°C to obtain a sheet-like product with a thickness of 0.5 mm. This was used as a test sample.

Comparative Example 2 Polyimide precursor (Nippon Polyimide, NE2000)
The fine powder was mixed with the same coconut shell activated carbon as used in Example 1 in a weight ratio of 60/40, poured into a mold with a thickness of 0.5 mm, and heated at 120°C under a pressure of 15 kg/cm2. It was formed into a sheet. Next, while still in the formwork, 260
A heat treatment was performed at ℃ for 4 hours to obtain an activated carbon-containing polyimide sheet. This was used as a test sample.

Comparative Example 3 The same coconut shell activated carbon used in Example 1 was mixed and dispersed in a vinyl acetate emulsion at a solid content ratio of 70/30, and formed into a 0.5 mm thick sheet. ℃3
Dry for 0 minutes. This was used as a test sample.

[0016] Regarding the above test samples, the temperature at 40°C
Carbon tetrachloride adsorption performance, time required for saturated adsorption, ventilation performance, flexibility, and heat reactivation activity were measured. The results are summarized in Table 1. In addition, the activated carbon effectiveness in the table is
Comparative calculations were made assuming that the adsorption amount of carbon tetrachloride in the activated carbon alone before the mixing treatment was 100, and that the adsorption of carbon tetrachloride in the test sample was due to the action of the activated carbon alone. 100 indicates that the adsorption capacity of activated carbon has not decreased at all.

[0017]

[Table 1]

Example 3 Polyester knits were laminated on both sides of the fired product obtained in Example 2 with activated carbon/PTFE resin = 70/30 to obtain a three-layer laminate product. In this case, adhesion between each layer was achieved by applying a polyurethane adhesive in dots. This laminate was flexible and showed little deterioration in carbon tetrachloride adsorption performance. J
The permeability measured by IS-L-1099B method is 625g/
It was m2hr.

Claims (5)

[Claims] 1. An adsorbent material comprising a polytetrafluoroethylene resin molding containing adsorbent powder with a particle size of 0.5 mm or less. 2. The material of claim 1, wherein said polytetrafluoroethylene resin is a stretched product. 3. The material according to claim 1 or 2, wherein the polytetrafluoroethylene resin is a sintered product. 4. Claims 1 to 3, wherein the molded body is a sheet.
Any material. 5. The material of claim 4, wherein said sheet is laminated to a fabric.