JPS5857210B2 - Method for manufacturing adsorbent sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to adhesion of activated carbon fibers to sheet materials.

A well-known method for making gas-absorbing sheets is to fix activated carbon to the sheet material using a fixing agent, but in practice this method requires the assistance of a large amount of fixing agent, and the amount of fixing agent is limited. If there is little friction, it will easily fall off due to slight friction or vibration.

When adhering to a sheet material with a dispersion containing a large amount of adhesion agent, the adhesion agent coats the activated carbon, greatly reducing the activated carbon's original gas adsorption ability, making it difficult to achieve both adhesion and adsorption properties. It is.

The present invention focuses on the deficiencies of the prior art described above, and provides a method that fundamentally overcomes the above-mentioned overflow based on a completely new idea. This is a method for producing an adsorbent sheet, characterized by applying an impregnating liquid containing air bubbles and dispersing short carbon fibers to a porous sheet material.

Activated carbon fibers are attached to the sheet material in a wet state, and when dry, they do not fall off easily even if the amount of adhesive is extremely small compared to the fiber tangles.

The activated carbon fiber used in the present invention is cellulose,
Organic fibers such as acrylic, phohar, lignin, phenol, and pitch are carbonized and activated to provide adsorption ability.

It is preferable to use short activated carbon fibers containing 80% or more of short fibers having a length of 0.05 to 5 mm.

Activated carbon fibers shorter than 0.05 mm are in a state substantially similar to powdered or granular activated carbon and easily fall off.

If the distance is 5 or more, the fibers become entwined with each other in the dispersion liquid, making it difficult to obtain uniform dispersion of the activated carbon fibers.

Porous sheet materials in the present invention include natural or regenerated fibers such as cotton, rayon, pulp, linen, and wool, base or semi-synthetic fibers such as acetate, polyester, polyamide, and polyolefin, and inorganic fibers such as glass. In addition to knitted fabrics, non-woven fabrics, dry cloth paper, wet-laid paper, etc., there are also sheets made of thin and uniformly spread sheets or slivers of these fibers.

Inserting air into the activated carbon fiber dispersion to form an air/water emulsion has a thickening effect on the impregnating liquid, allowing for uniform dispersion of the activated carbon fibers, and for impregnation in regularly spaced striped patterns. Make lines sharp.

The viscosity of the impregnating liquid during adhesion is 1000-50000 c
ps is preferred.

Thickening using a surfactant hardly lowers the gas adsorption performance of activated carbon fibers compared to thickening agents such as adhesives that have high coating properties.

The addition of small amounts of glue or adhesive to the surfactant to further increase the stability of the air/water emulsion may also provide good results.

When the air/water emulsion dispersion of activated carbon fibers comes into contact with the sheet material, the air bubbles are destroyed by capillary action, and the activated carbon fibers adhere to the surface of the sheet material or permeate into the interior of the sheet material.

This phenomenon can be accelerated by suctioning the activated carbon fiber dispersion from the back side of the sheet material after application, but suction is not always necessary.

When a sheet material is applied with a thickened dispersion liquid that does not contain air, the activated carbon fibers swell up and adhere to the sheet material even after drying, resulting in poor abrasion resistance.

Even if the fibers contain relatively short activated carbon fibers of 0.05-5 mm, if the volume concentration of the fibers is high, the fibers will end up together in the dispersion, making it difficult to disperse them uniformly, making it difficult to achieve the desired amount of activated carbon fibers. cannot be applied uniformly to the sheet material.

Lowering the volumetric concentration of fibers by increasing the amount of water is not preferable in terms of drying speed after impregnation and energy costs.

Air is a convenient diluent for storage.

In the present invention, it is preferable to use a foaming liquid having a volume ratio of liquid to air of 5-4.

When the volume ratio is less than 1:0.5 or more than 1:4, the movement of air bubbles in the dispersion makes it difficult to obtain a dispersion with a stable fiber to volume concentration.

Surfactants for foaming include anionic surfactants, nonionic surfactants, and
Amphoteric surfactants are preferred, such as anionic surfactants such as dodecylbenzenesulfonate, sodium lauryl sulfate, potassium stearyl sulfate, sodium oleyl sulfate, sodium laurate, sodium myristate, octylphenyldecacrylic ether, Nonionic surfactants such as nonylphenyl pentadecaglycol ether, lauric acid jetanolamide, anionic nonionic surfactants such as sulfated lauryl glycol ether, sulfated stearyl glycol ether, sulfated nonylphenyl glycol ether, lauryl methyl betaine Examples of preferable foaming agents include amphoteric surfactants such as , lauryl dimethyl betaine, and oleyl dimethyl betaine.

The foaming agent may be used alone or as a mixture of two or more.

To prepare the impregnating liquid in the present invention, a predetermined amount of the above-mentioned foaming agent and a foam stabilizer added thereto as necessary are foamed by any method such as air injection method, spray method, homomixer stirring method, etc. Activated carbon fibers mainly having a length of 0.05 to 5 mm are added to the liquid and stirred until uniformly dispersed.

The thus obtained foamed dispersion of activated carbon fibers is printed or coated by a conventional method and then dried.

The present invention is particularly useful for manufacturing a filter material for making a polymeric filter plug for cigarettes, which can be manufactured integrally with a polymeric filter plug for cigarettes consisting of a portion impregnated with activated carbon and a portion not impregnated with activated carbon. .

Conventionally, polymerized filter plugs for cigarettes include a single plug rolled up with acetate, pulp, or other fibrous or sheet-like material, and a plug rolled up with carbon or other additives either directly or added to the above fibers or sheets. A method is used in which plugs of different types are manufactured, cut to a certain length, and then alternately combined and wound up.

However, by applying the present invention, polymeric filter plugs can be made all at once using the same method as making a single filter plug.

That is, activated carbon fiber rectangular fibers are attached to at least one surface of a porous sheet in a constant width at regular intervals in the longitudinal direction,
Next, a filter plug can be manufactured by rolling up this in a direction perpendicular to the longitudinal direction to form a cylindrical bottom shape, wrapping it with wrapping paper, and cutting it to a predetermined length.

In the filter plug manufactured by this method, the activated carbon fibers are intertwined with the filter base material, so that the adsorbent does not escape from the filter, and it also has a good odor and taste.

Example 1 30 grams of felt-like activated carbon fiber with a 5-denier rayon nonwoven fabric as a precursor and 11 grams of water were placed in a household mixer.
After stirring for a minute, the mixture was dehydrated and dried to prepare activated carbon fibers mainly having a length of 0.5-5 mtn.

5 parts of the activated carbon fibers prepared above were added to an air/water emulsion prepared by stirring 10 parts of sodium dodecylbenzenesulfonate, 0.1 part of polyvinyl pyrrolidone, and 89.9 parts of water at 6000 rpm for 3 minutes using a homomixer. The mixture was further stirred until the carbon fibers were uniformly dispersed.

The liquid-to-air ratio at this time was 1:1.

The impregnating liquid was printed on a lead paper towel (dry non-woven fabric manufactured by Honshu Paper Industries) using a printing machine and a printing machine in a stripe shape with a width of 7 mm in the printed part and a width of 10 Tt 11 L in the non-printed part, and dried at 120°C to form a gas-absorbing structure. I got it.

Example 2 An impregnation liquid was prepared in the same manner as in Example, except that an air/water emulsion prepared from 4 parts of soap obtained by saponifying beef tallow, 0.4 parts of carboxymethylcellulose, and 95.6 parts of water was used. .

A rectangle with a width of 7 mm and a length of 50 mm is placed on a porous sheet material with a width of 5 cIrL and a uniform thickness of a single yarn made of acetyl cellulose with an acetyl value of 40% and a denier of 5 and a number of filaments of 4,000. A hollowed out plate was coated with the impregnating solution and dried at 120°C to obtain a material for a cigarette filter to which activated carbon fibers were attached in stripes.

Example 3 An activated carbon fiber dispersion having the same composition as in Example 2 was coated over the Japanese Pharmacopoeia gauze (type 1) to a thickness of 2 cm, and the side of the dried sheet with less activated carbon fiber adhesion was glued. When the product was attached to the inner wall of a refrigerator by 0.1 m, the deodorizing effect was superior to that of a three-dimensional container filled with granular activated carbon, and the space occupied by the container could be used effectively.

Claims (1)

[Claims] 1. A method for producing an adsorbent sheet, which comprises applying an impregnating liquid containing air bubbles to a porous sheet material in which short activated carbon fibers are dispersed.