JPH1033982A - Activated carbon fiber adsorbing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adsorbing material which has both end parts almost free from the deterioration of its adsorbing capability and does not have the inclusion of resin fragments in the filtrate by covering the inner and outer peripheral faces of a cylindrical form composed mainly of activated carbon fiber with a water permeable fiber layer and also retaining the end parts with ethylenevinyl acetate resin. SOLUTION: A sheet-like material composed mainly of activated carbon fiber such as of pitch or polyacrylonitrile is rolled into a cylindrical form 1. Then the inner and outer peripheral faces of this cylindrical form 1 are covered with water permeable fiber layers 2, 3 such as polyester or polypropylene. At the same time, both end parts 5 of the cylindrical form 1 are retained with ethylenevinyl acetate resin. This ethylenevinyl acetate resin is hydrophilic and therefore, adheres to the surface but does not penetrate into the pore, and for this reason, still maintains its adsorption capability even on the both end parts. Besides, the ethylenevinyl acetate resin is pliable and is hardly breakable so that activated carbon fiber is not included as carbon dust into the filtrate from the broken part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an activated carbon fiber adsorbent suitable as a filter element for a household water purifier used for purifying tap water or the like.

[0002]

2. Description of the Related Art Tap water used for drinking at home usually contains 1 ppm of chlorine for sterilization. Thus, tap water containing chlorine causes discomfort to drinkers due to its chlorine odor. Also, during the drought period of the tap water source, mold odor that cannot be removed by the ordinary water purification treatment at the water purification plant remains in the tap water, giving the person who drinks more discomfort than the chlorine odor.

In order to remove such malodors or floating substances such as chlorine odor and moldy odor from tap water, a filter element made of activated carbon alone or a combination of a filter element made of activated carbon and a filter element made of hollow fibers is used. It is widely used to filter tap water with a built-in household water purifier.

As the activated carbon used in the filter element made of activated carbon incorporated in the above-mentioned household water purifier, a fibrous one is used instead of a granular or powdery one. The reason is that activated carbon fiber is fibrous, so it has a large external surface area, good contact efficiency with water, high adsorption speed, and is easy to process into nonwoven fabric or paper-like material. This is because, by winding a nonwoven fabric or the like into a cylindrical or columnar shape, it can be formed into a cylindrical or columnar molded body widely used in water purifiers.

The specific shape of a filter element made of activated carbon fiber incorporated in a household water purifier is designed to pass through the inner and outer peripheral surfaces of a cylindrical body mainly composed of activated carbon fibers or the outer peripheral surface of a columnar body. It is covered with an aqueous fiber layer. The fiber layer protects the cylindrical body and columnar body mainly composed of activated carbon fiber, and prevents the activated carbon fiber from falling off from the side of this molded body. Activated carbon fibers are prevented from being mixed into the filtered water. However, since such a filter element is manufactured by cutting a long cylindrical body or a columnar body into a predetermined length, the powder of activated carbon fibers falls off from both ends of the filter element. There was a problem.

[0006] To solve this problem, Japanese Utility Model Application Laid-Open No.
No. 19 proposes a filter in which both ends of a cut cylindrical body are fixed with solid paraffin. Certainly, by solidifying both ends of the cut cylindrical body with solid paraffin, it is possible to reduce the falling of activated carbon fiber powder from both ends, but this filter has the following problems. . First, solid paraffin is non-polar, but activated carbon adsorbs non-polar one well, so solid paraffin penetrates not only into the surface of activated carbon fiber but also into the inside of fine pores, and adsorbs both ends of the cylindrical body. Ability disappears. In addition, solid paraffin is hard and brittle and thus easily chipped, and the chipped solid paraffin and the activated carbon fiber in the part where the solid paraffin is chipped are mixed into the filtered water.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and has a small decrease in the adsorbing ability of both ends fixed with the resin of the adsorbent, and the resin used for the fixing is chipped or chipped. It is an object of the present invention to provide an activated carbon fiber-based adsorbent in which activated carbon fibers in a portion which does not become coal dust and are not mixed into filtered water.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention has the following configuration. (1) The inner and outer peripheral surfaces of a cylindrical body mainly composed of activated carbon fibers are covered with a water-permeable fiber layer, and both ends of the cylindrical body are fixed with ethylene vinyl acetate resin. Activated carbon fiber based adsorbent. (2) An activated carbon fiber system characterized in that the outer peripheral surface of a columnar body containing activated carbon fibers as a main component is covered with a water-soluble fiber layer, and both ends of the columnar body are fixed with ethylene vinyl acetate resin. Adsorbent.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. As shown in FIGS. 1 and 2, the activated carbon fiber-based adsorbent of the present invention has a water-permeable fiber layer 2 having both an inner peripheral surface and an outer peripheral surface of a cylindrical body 1 mainly composed of activated carbon fibers. , 3
3 and, as shown in FIG. 3, the outer peripheral surface of the columnar body 4 is covered with a water-permeable fiber layer 3. Both ends of the cylindrical body 1 and the cylindrical body 4 are respectively It is fixed at a fixing portion 5 using ethylene vinyl acetate (EVA) resin.

The activated carbon fibers used in the present invention are porous and have a high adsorptive function which can be obtained by a usual method using fibers of pitch type, polyacrylonitrile type, cellulose type or phenol type. Having a specific surface area of preferably 500 m ² / g or more, especially 700 to 2500 m ² / g
belongs to.

The cylindrical body 1 and the columnar body 4 containing activated carbon fiber as a main component can be obtained by winding a sheet containing activated carbon fiber as described later. The material constituting the body 4 may be only activated carbon fibers, or may be a mixture of natural fibers and thermoplastic synthetic fibers. In this case, if the thermoplastic synthetic fibers are mixed, the cylindrical body or the columnar body and the sheet-like material serving as the water-permeable fiber layer can be integrated by heat treatment. Further, a nonwoven fabric made of thermoplastic synthetic fiber may be overlapped on one or both sides of a sheet made of activated carbon fiber, and a cylindrical body or a columnar body mainly composed of activated carbon fiber may be formed from the sheet. . Furthermore, the basis weight of a sheet-like material for forming a cylindrical body or a cylindrical body mainly composed of activated carbon fiber is 30%.
の も の 150 g / m ² are preferred.

The sheet-like material serving as the fibrous layers 2 and 3 covering the inner and outer peripheral surfaces of the cylindrical body 1 and the cylindrical body 4 containing activated carbon fibers as a main component has a basis weight of 10 to 100 g / m ² . It is preferred to use one. When the basis weight is less than 10 g / m ² , the protection effect of the cylindrical body 1 and the columnar body 4 is reduced, and when the basis weight is more than 100 g / m ² , the protection effect is sufficient, but the pressure loss is increased,
The capacity of the adsorbent becomes large, and the device to be incorporated becomes large, which is not preferable.

[0013] Materials constituting the water-permeable fiber layer include:
For example, polyester, polyamide, polyolefin such as polyethylene and polypropylene, cotton, rayon, or polyester for the core, and core-sheath composite fiber using the copolyester or polyolefin for the sheath are used. Among them, polypropylene, polyethylene, and polyester are used. Core-sheath composite fibers with polyolefin are preferably used. The sheet-like material serving as the fiber layer can be formed of a nonwoven fabric of long fibers or short fibers, or a cloth-like material obtained by knitting and weaving yarn.

As described above, the activated carbon fiber-based adsorbent of the present invention is obtained by covering the inner and outer peripheral surfaces of a cylindrical or columnar body containing activated carbon fibers as a main component with a water-permeable fiber layer. However, as a method of integrating the cylindrical body or the columnar body with the fiber layer, there is a method of covering both with a net or the like.

As another method, a mixture of activated carbon fiber and thermoplastic synthetic fiber is used as a cylindrical body or a columnar body, and a sheet serving as a fiber layer is arranged on the side surface of the cylindrical body or the columnar body and heated. There is a method in which the activated carbon fiber and the thermoplastic synthetic fiber or the thermoplastic synthetic fiber are fused together by heat-treating and partially or entirely melting the thermoplastic synthetic fiber. This method of integrating with the fiber layer is preferred.

As the thermoplastic synthetic fiber to be mixed with the activated carbon fiber, for example, polyethylene-polypropylene, copolyester or a core-sheath composite fiber having a core of polyester and a sheath of polyethylene, polypropylene or copolyester is used. . The mixing ratio of activated carbon fiber and thermoplastic synthetic fiber is 98: 2 to 40:60, preferably
95: 5 to 60:40. If the mixing ratio of the activated carbon fibers is larger than the above range, the moldability of the adsorbent deteriorates, and the adhesion between the cylindrical body or the columnar body and the fiber layer also deteriorates. On the other hand, if the mixing ratio is smaller than the above range, the performance of adsorbing and removing chlorine odor, musty odor, and the like is reduced.

As a method of mixing the activated carbon fiber and the thermoplastic synthetic fiber, for example, there is a method in which the activated carbon fiber and the thermoplastic synthetic fiber are put into a carding machine at a predetermined ratio, mixed with a card and mixed to form a sheet. . Alternatively, a method may be used in which the activated carbon fiber and the thermoplastic synthetic fiber are mixed and wet-formed into a sheet by a papermaking method. Further, natural fibers such as hemp and cotton may be mixed therewith. When natural fibers are mixed, the mixing amount is preferably 30% by weight or less.

The inner and outer peripheral surfaces of the above-mentioned cylindrical body or columnar body containing activated carbon fibers as a main component are covered with a fiber layer, but both ends of the cylindrical body or columnar body are exposed. And
As it is, the powder of activated carbon fiber may be mixed into the filtered water as coal dust. Therefore, in the present invention, it is necessary to fix both ends of the cylindrical body or the columnar body with the fixing portions using the EVA resin. EVA resin has an ester group as a functional group and therefore is more hydrophilic than solid paraffin. Therefore, even if both ends of a cylindrical or columnar body are impregnated with a molten EVA resin, it adheres to the surface. However, it does not penetrate into the inside of the micropores, and the adsorption ability can be left at both ends. Further, the EVA resin is flexible and hardly chipped even when subjected to an impact, and the activated carbon fiber does not enter the filtered water as charcoal dust from the chipped portion.

As the EVA resin used in the present invention, those having a softening point of 90 to 110 ° C. and satisfying the standard for food additives are preferable. EV on both ends of cylindrical or cylindrical body
To fix with the fixing part using resin A, EVA
A method in which the resin is melted and cast into a film shape, the end of a cylindrical body or a columnar body is pressed, and the melted EVA resin is permeated can be adopted.

Next, an example of a method for producing the activated carbon fiber-based adsorbent of the present invention will be described. After winding a sheet material to be a fiber layer around a rod-shaped molding jig coated with polytetrafluoroethylene, a sheet material of activated carbon fiber or a mixture of activated carbon fiber and thermoplastic synthetic fiber is formed. Wrap from above. Furthermore, after winding a sheet-like material having the same or different weight as that wound on the inner layer side, a part or all of the thermoplastic synthetic fiber is melted by heat treatment, and the activated carbon fiber and the thermoplastic synthetic fiber and The activated carbon fiber and the sheet material of the inner layer and the outer layer are fused and integrated. Here, the temperature of the heat treatment is preferably 5 to 40 ° C. higher than the melting point of the thermoplastic synthetic fiber. Then, after cooling, the molding jig is removed to obtain a cylindrical activated carbon fiber-based adsorbent. Further, the long product obtained above was cut into a predetermined length, and the end of the cut product was pressed and melted by melting an EVA resin on a plate and casting it into a film. Infiltrate the EVA resin into the end and then the EVA resin into the other end as well,
The activated carbon fiber-based adsorbent of the present invention, which has been cooled and has a cylindrical shape, is obtained. The column-shaped activated carbon fiber-based adsorbent of the present invention uses a rod-shaped molding jig having a smaller diameter than that of forming a cylindrical body. After a cylindrical body is formed in the same manner as described above except that no is used, a rod-shaped molding jig is removed, and then the cylindrical body is squeezed to crush the hollow portion to obtain a columnar shape.

Among the activated carbon fiber-based adsorbents of the present invention, those having a cylindrical shape can be made to pass water from the outer peripheral surface side to the inner peripheral surface side or from the inner peripheral surface side to the outer peripheral surface side to form a fibrous layer and activated carbon fiber. It filters suspended matter and the like with a cylindrical body mainly composed of, and adsorbs substances causing chlorine odor and musty odor with the cylindrical body. In addition, those having a columnar shape filter and adsorb water by passing water in the diameter direction or the axial direction.

The activated carbon fiber-based adsorbent of the present invention is formed by covering the inner and outer peripheral surfaces of a cylindrical body mainly composed of activated carbon fibers or the outer peripheral surface of a cylindrical body with a water-permeable fiber layer. The layer protects the cylindrical or cylindrical body mainly composed of activated carbon fiber, and prevents the activated carbon fiber from falling off from the side of this molded body, thereby allowing the water to flow into the filtered water in the circumferential direction. Activated carbon fibers can be prevented from mixing.

Further, since both ends of the cylindrical body or the columnar body are fixed, it is possible to prevent the activated carbon fiber powder from being mixed into the filtered water as coal dust from both ends not covered with the fiber layer. it can. Moreover, since hydrophilic EVA resin is used as the fixing material, even if both ends of the cylindrical or columnar body are impregnated with the molten EVA resin, they adhere to the surface but reach inside the micropores. Does not permeate, and the adsorption ability can be left at both ends. In addition, EVA
Since the resin is flexible, it is not easily chipped even when subjected to an impact, and the activated carbon fiber does not enter the filtered water as coal dust from the chipped portion.

[0024]

Next, the present invention will be described in detail with reference to examples. Example 1 Unitika activated carbon fiber A-15 (specific surface area 1540 m ² /
g) and a core-sheath type composite fiber whose core is polyethylene terephthalate and whose sheath is a copolymerized polyester with a melting point of 120 ° C.
(Melty: manufactured by Unitika Ltd.) was blended at a weight ratio of 60:40, and uniformly mixed with a card machine to produce a sheet having a basis weight of 80 g / m ² .

Next, a non-woven fabric made of a core-sheath composite fiber having a core of polyethylene terephthalate and a sheath of polyethylene was wound around a molding jig coated with polytetrafluoroethylene to form a fiber layer having a basis weight of 30 g / m ² . . After wrapping a sheet containing the activated carbon fiber as a main component thereon, wrapping the non-woven fabric thereon further to provide a basis weight of 30%.
An outer fiber layer of g / m ² was formed to form a cylindrical body having an outer diameter of 66 mm, an inner diameter of 30 mm, and a length of 120 cm. This cylindrical body is heated at 145 ° C for 3
After being heat treated for one hour, they were integrated. After cooling, the molding jig was extracted and cut into 30 cm lengths.

Next, EVA resin (Molecome Coel PK-100, manufactured by Matsumura Petroleum Institute, softening point 95
° C) and cast it into a film. Press the end of the cylindrical body cut to 30 cm into the film, infiltrate the molten EVA resin, and infiltrate the EVA resin into the other end in the same manner. After cooling, the activated carbon fiber-based adsorbent of the present invention was obtained.

The activated carbon fiber based adsorbent obtained above was
Adjusted water, which is attached to a resin cylinder of 00 mm and 330 mm in height and added with 2 mg / l of free chlorine and 50 ng / l of 2-methylisoborneol (mould odor component) to distilled water from the outer side of the activated carbon fiber-based adsorbent Water was passed through the peripheral side at a rate of 6 L / min, and filtered water was taken out from the upper part. The conditioned water had a chlorine odor and a musty odor. However, when the filtered water after passing 50 m ³ was checked, no chlorine odor or musty odor was detected. -Methylisoborneol could not be detected. Further, neither end of the adsorbent was chipped, and activated carbon fibers did not enter the filtered water as coal dust.

[0028]

The activated carbon fiber-based adsorbent of the present invention protects a cylindrical body or a columnar body containing activated carbon fibers as a main component in a fiber layer, and prevents the activated carbon fibers from falling off from the side surface of the molded body. Thus, it is possible to prevent the activated carbon fiber from entering the filtered water from the circumferential direction. In addition, since both ends are fixed, it is possible to prevent the activated carbon fiber powder from entering the filtered water as coal dust from both ends not covered with the fiber layer. Further, the adsorbing ability remains at both ends, and the ends are hardly chipped even when subjected to an impact, so that it is possible to prevent the activated carbon fibers from entering the filtered water as coal dust from the chipped portions. The activated carbon fiber-based adsorbent of the present invention is suitable as a filter element for a household water purifier used for purifying tap water and the like.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a cylindrical activated carbon fiber-based adsorbent of the present invention.

FIG. 2 is a longitudinal sectional view of the activated carbon fiber-based adsorbent of FIG.

FIG. 3 is a perspective view showing one embodiment of a columnar activated carbon fiber-based adsorbent of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical body 2 Fiber layer on inner peripheral surface side 3 Fiber layer on outer peripheral surface side 4 Columnar body 5 Fixed part

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Mayumi Makiyama, Inventor 23 Uji Kozakura, Uji City, Kyoto Prefecture Unitika Central Research Laboratory

Claims (2)

[Claims] Claims: 1. An inner peripheral surface and an outer peripheral surface of a cylindrical body mainly composed of activated carbon fibers are covered with a water-permeable fiber layer.
An activated carbon fiber-based adsorbent, wherein both ends of the cylindrical body are fixed with ethylene vinyl acetate resin. 2. The activated carbon according to claim 1, wherein an outer peripheral surface of the columnar body mainly composed of activated carbon fibers is covered with a water-soluble fiber layer, and both ends of said columnar body are fixed with an ethylene vinyl acetate resin. Fiber-based adsorbent.