JPS63137721A - Adsorptive sheet - Google Patents

Abstract

PURPOSE:To improve adsorptivity and permeability for various substances by laminating nonwoven fabric mixed with composite fiber, wherein nonwoven fabric or the like consisting of only high-m.p. synthetic fiber is used as a core component and low-m.p. synthetic resin is used as a sheath component, on nonwoven fabric made of activated carbon fiber. CONSTITUTION:Nonwoven fabric 3 made of activated carbon fiber is manufactured by fusing and reinforcing a joining point with composite fiber wherein high-m.p. synthetic resin is used as a core component and low-m.p. synthetic resin is used as a sheath component. Nonwoven fabrics 2, 4 which consist of only high-m.p. synthetic fiber respectively, or are obtained by mixing composite fiber wherein high-m.p. resin is used as the core component and low-m.p. synthetic resin is used as the sheath component are fused on both surfaces of the nonwoven fabric 3 made of activated carbon fiber and laminated thereon so that these are not separated from one anther by interlocking of fiber, thus an adsorptive sheet 1 is manufactured. In this case, it is necessary that ion- exchange fiber is mixed with at least one of nonwoven fabrics 2, 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adsorbent sheet containing activated carbon fibers.

[Conventional technology]

Powdered and granular activated carbon is generally used as an adsorbent for various substances in gases and solutions, but it has also been proposed that activated carbon be made into fibers to form filters that allow gases and solutions to easily pass through. It's bright.

[Problem that the invention seeks to solve]

However, powdered or granular activated carbon.

Because there is a risk of contamination with the gas or solution during adsorption, adsorption is usually performed within a limited volume such as a filter, and it takes considerable pressure to send the gas or solution into the volume. There are drawbacks. In addition, activated carbon fibers have been improved with respect to the above-mentioned drawbacks, but their adsorption power is significantly reduced due to the adhesion of mist and dust such as oil and resin in gas, and the adsorption power of activated carbon fibers is significantly reduced due to the adhesion of oil droplets and suspended particles in solutions. There was a drawback that things could stick to it. Activated carbon fibers also have the disadvantage of relatively poor adsorption power for low-molecular-weight ionic substances such as hydrogen halide, hydrogen sulfide, and ammonia in gases, and chlorine ions, nitrate ions, nitrite ions, and ammonia ions in solutions. Ta.

[Means to solve all problems]

In view of the current situation, the present invention has been developed to form a nonwoven fabric made of activated carbon fibers on one or both sides of which the bonding points are fused and reinforced with composite fibers containing a high melting point synthetic resin as a core component and a low melting point synthetic resin as a sheath component. , to prevent separation due to fusion, entanglement, etc., of nonwoven fabrics made only of high melting point synthetic fibers or nonwoven fabrics made of high melting point synthetic fibers, a high melting point synthetic resin as a core component, and a composite fiber mixture of a low melting point synthetic resin as a sheath component. This adsorbent sheet is characterized in that at least one of the nonwoven fabrics is mixed with ion-replaceable fibers so that they do not separate.

[Effect]

Since the adsorbent sheet in the present invention contains fibrous activated carbon, it has excellent adsorption properties for various substances, is porous and has excellent permeability, and the activated carbon is strongly retained.
It will not be lost due to mixing with gases, solutions, etc. In addition, since the activated carbon is protected on at least one side by a synthetic fiber non-woven fabric, the synthetic fiber non-woven fabric can remove gas, dust in clear liquid, etc., and the sudden adsorption of activated carbon caused by dust and mist. It is possible to avoid significant reductions. Furthermore, all polar substances that activated carbon fibers do not adsorb, such as ammonia in the gas and chlorine ions and ammonia ions in the solution, are all adsorbed, making it possible to remove a wide range of substances.

〔Example〕

The present invention will be explained in detail below according to the illustrated embodiments.

In FIG. 1, reference numeral 1 is an adsorbent sheet in which composite fiber-containing synthetic fiber nonwoven fabrics 2 and 4 are laminated on both sides of a live charcoal fiber nonwoven fabric 3 and fused by heating.

The activated carbon fiber non-woven fabric 3 is made by fully mixing activated carbon fibers with composite fibers including a high melting point synthetic resin as a core and a low melting point synthetic resin gold sheath, and melting the low melting point synthetic resin to fuse all contact points with the activated carbon fibers. It is. Here, the activated carbon fiber is made by polymerizing coal tar to form an isotropic spinning pitch, which is melt-spun to form a full pinch yarn, and then treated at high temperature to make it infusible and carbonized, allowing it to absorb oxidizing gases. The above carbonization process develops a network structure, and elements other than carbon are released as gas, creating a large number of degassing pores (macropores) and increasing the surface area. Then, in the subsequent activation step, etching is performed using oxidizing gas, and countless pores (micropores) with pore diameters on the order of angstroms are generated on the increased surface, resulting in a significant increase in surface area.Adsorption of various substances is ,
The adsorption is carried out through these pores, and the adsorbed substance is determined by the pore diameter, and the amount of adsorption is determined by the number, pore diameter, and depth of the pores. The pore diameter, number, depth, etc. of the pores vary depending on the raw materials and manufacturing conditions, but are between 500 and 2500 d/f! It is desirable to have a specific surface area of . The diameter of the activated carbon fibers is preferably small, for example 15 to 20 microns. Activated carbon fibers may be either long fibers or short fibers, and in the case of long fibers, a large number of extruded fibers are taken up in an air stream and randomly piled up on a conveyor belt to form a nonwoven fabric. In this case, it is formed by cutting extruded fibers into appropriate lengths.

For the composite fibers to be mixed with activated carbon fibers, various synthetic resins such as polyester, polypropylene, polyamide, etc. are used for the core component, and the synthetic resin for the sheath component has a melting point of at least 40°C or lower than that of the synthetic resin for the core component. It is desirable to use one with The synthetic resins of the core component and sheath component are preferably of the same type. The synthetic resins for the core component and sheath component are preferably of the same type, but a combination of different synthetic resins may be used as long as they have compatibility.

When the composite fiber is made of polyester, the softening point is 2.
The core component is polyester with a temperature of 40℃ or higher.

It is preferable that the composite fiber is made of polyester having a softening point of 100 to 150°C as a sheath component. moreover.

Specifically, the core component is mainly polyethylene terephthalate, and the sheath component is one dibasic acid or its derivative, one glycol, and one or more dibasic acids or glycols different from these. An example of the latter is a copolyester containing terephthalic acid, isophthalic acid, and ethylene glycol as main components.

In addition to the above, polyethylene, polypropylene, etc. can also be used as the sheath component. When polyester is used as a composite fiber, bulkiness is required.

Excellent elastic recovery.

Other composite fibers include polypropylene as the core component,
The sheath components are polyethylene and polystyrene.

Ethylene propylene copolymers and the like are also preferred.

The fineness of the composite fiber is preferably 10 deniers or less, but is not limited thereto. The fineness of the core component of the composite fiber is 1/2 to 1/6 of the fineness of the entire composite fiber.It is preferable that the core component is cut into a length of 50 to 150 meters and crimped to facilitate fusing. .

Activated carbon fibers and composite fibers are supplied to cards, etc.

The fibers are opened and mixed to form a web, which is then fused to a joining point in a hot air oven or the like. This provides strength and bulk.

A soaked activated carbon fiber nonwoven fabric with elastic recovery properties is obtained.

A synthetic fiber nonwoven fabric is laminated on one or both sides of the obtained activated carbon fiber nonwoven fabric, but the synthetic fiber nonwoven fabric used here is made of fibers made of various synthetic resins such as polyester, polyamide, polypropylene, etc., and high melting point synthetic resin? As a core component,
It is almost equivalent to a sheath made of low melting point synthetic resin. Since both the activated carbon fiber nonwoven fabric and the synthetic fiber nonwoven fabric include composite fibers having a low melting point synthetic resin sheath, they can be fused together by heating during lamination.

Note that the activated carbon fiber nonwoven fabric 3 forming the adsorbent sheet 1,
At least one of the synthetic fiber nonwoven fabrics 2.4 is completely mixed with ion conversion fibers. Here, ion-converting fibers refer to only fibers containing ion-exchange groups, or mixed fibers with reinforcing fibers, or composite fibers with fibers containing all ion-exchange groups as a sheath and reinforcing fibers as a core. It's good as well.

Here, the ion exchange group is an anion conversion group.

Cation exchange groups, chelate groups, etc., and anion exchange groups can be obtained by treating haloalkylated threads with tertiary bases such as trimethylamine, dimethylamine ethanol, and secondary or lower amines such as isopropylamine and diethylamine. The basic anion or substituent group obtained is chlorsulfonic acid, the weakly acidic cation exchange group such as carboxylic acid, the strong acid cation exchange group obtained by sulfonation with concentrated sulfuric acid, etc., and the chelate group is iminodiacetic acid. Examples include, but are not limited to, chelate-forming functional groups such as a group, iminodipropionic acid, and the like.

In addition, various polymers such as ring-containing vinyl polymers, polyvinylpyridine, acrylic acid polymers, and methacrylic acid polymers are used as polymeric substances that can be introduced into the ion exchange fund.

The obtained adsorbent sheet is laminated with synthetic fiber non-woven fabric, which makes use of the full affinity of the synthetic fibers to remove dust, mist, etc. that would otherwise reduce the adsorption power of activated carbon, thereby increasing the sustainability of the adsorption power. It is possible to prevent the accidental detachment of activated carbon and the adhesion of dirt due to direct contact with activated carbon. It is also used to remove acidic gases such as hydrogen sulfide, hydrogen halides, and sulfur dioxide gas, basic gases such as ammonia, and remove chromic acid, amines, and pigments.

The adsorbent sheet according to the present invention can be used for filters for cleaning the air in factories, etc., as well as for medical products such as masks, medical sheets, medical suits, base fabrics for ships, bandages, covers, diapers, and garbage for garbage disposal. bags, curtains,
Used for various purposes such as gloves and fire evacuation equipment.

Furthermore, it is also possible to incorporate various materials in addition to the above.1 For example, if ultra-fine copper fibers of about 20 to 40 μΦ are mixed into any layer, the sterilizing property and antistatic effect will be improved, and the water absorption property will be improved. If all the fibers are mixed in, water absorption will be improved.

In FIG. 2, the adsorbent sheet 1' includes a synthetic fiber nonwoven fabric 2' that does not contain composite fibers on both sides of an activated carbon fiber nonwoven fabric 3;
The activated carbon fiber nonwoven fabric 3 is the same as that shown in FIG. 1, and the synthetic fiber nonwoven fabrics 2', 4'
is a synthetic fiber nonwoven fabric similar to that shown in FIG. 1 except that it does not contain composite fibers.

Ion exchange fiber is mixed in at least one of them.

In the above figures, the synthetic fiber nonwoven fabrics laminated on both sides of the activated carbon fiber nonwoven fabric 3 are all the same, but one side has synthetic fibers containing composite fibers, and the other side has synthetic fibers containing no composite fibers. Alternatively, only one side of the activated carbon fiber nonwoven fabric 3 may contain composite fibers, or the entire synthetic fiber nonwoven fabric may be used without containing composite fibers. In this case, if all the conjugate fibers are used, the bonding with the activated carbon fibers can be carried out by fusion, and if no conjugate fibers are used, the bonding with the activated carbon fibers can be carried out by needle punching. In this case as well, ion exchange fibers are mixed in at least one layer, as in the case of FIGS. 1 and 2.

〔Effect of the invention〕

As is clear from the above description, the present invention has excellent adsorption and permeability to various substances, and also has activated carbon that is firmly retained and does not get lost, and also prevents gases, mist in solutions, etc. It is possible to achieve excellent practical effects, such as preventing a sudden drop in the adsorption power of activated carbon fibers due to dust, and being able to adsorb ionic substances and polar substances that cannot be adsorbed by activated carbon fibers.

[Brief explanation of the drawing]

The drawings fully illustrate embodiments of the present invention, with FIG. 1 being a side view of the first embodiment, and FIG. 2 being a side view of another embodiment. 2, 4: Synthetic fiber non-woven fabric 3: Activated carbon fiber non-woven fabric Patent applicant: Unitika Co., Ltd. Agent Michio Oshima 1 1 (+
＋□) Procedural Amendment Figure 1 September 16, 1988 Patent Application No. 281660 of 1988 2, Name of Invention Adhesive Sheet 3, Relationship with the person making the amendment Patent Applicant Address Higashi, Amagasaki City, Hyogo Prefecture Honmachi 1-50 Name (45
0) Unitika Co., Ltd. Representative Taira 1) Yutaka 4, Agent 105 Phone 501-4552 Address
This is a voluntary amendment, 4th floor, Shimazaki Building, 1-2-14 Toranomon, Minato-ku, Tokyo6.The number of inventions increased by the amendment (1), from page 4, line 18 to page 5, line 8 of the specification.
Pitch thread...Adsorbed object J is corrected as follows. It is obtained by forming an r-pitch yarn, then treating it at a high temperature to make it infusible, and activating it in an oxidizing gas. The activation process in the atmosphere produces countless pores (micropores) with pore diameters on the order of angstroms on the surface, significantly increasing the surface area. Adsorption of each substance is done through these pores, and the adsorbed material is determined by the pore size.

Claims (1)

[Claims] A nonwoven fabric made only of high melting point synthetic fibers or A nonwoven fabric made of high melting point synthetic fibers mixed with composite fibers having a high melting point resin as a core component and a low melting point synthetic resin as a sheath component is laminated so as not to separate due to fusion and entanglement of the fibers. One is an adsorbent sheet that is characterized by being mixed with ion-exchange fibers so that they do not separate.