JP2023132942A - Fibrous activated carbon knitted fabric - Google Patents

Abstract

To provide a fibrous activated carbon which is light in weight, has high air-permeability, and has stretchability.SOLUTION: A fibrous activated carbon knitted fabric is formed of a warp knitted fabric and has a bone-dry mass of 30 g/m2 or more and less than 80 g/m2.SELECTED DRAWING: None

Description

The present invention relates to a fibrous activated carbon knitted fabric.

Sheet-like fibrous activated carbon is used in medical products such as masks, deodorizing pads, and deodorizing sheets, protective clothing that protects the body from harmful gases, various air purifiers, various adsorption elements used in the liquid phase, electrical reaction fields, etc. It is used for battery electrodes, electric tank electrodes, etc. As such a sheet-like fibrous activated carbon, for example, Patent Document 1 proposes a fibrous activated carbon knitted fabric. Further, Patent Document 2 proposes a fibrous activated carbon multilayer fabric.

Methods for obtaining sheet-shaped fibrous activated carbon include a method in which raw organic fibers are made into a non-woven fabric such as felt, a woven fabric, or a knitted fabric, and then carbonized and activated, or a raw organic fiber is carbonized and activated to produce fibrous activated carbon. After obtaining, a method of processing it into a nonwoven fabric or the like can be mentioned.

JP2002-212838 JP2014-227307 〇〇

However, with recent global warming, reducing heat stress when wearing protective clothing is an issue, and there is a demand for activated carbon that is lightweight, highly breathable, and stretchable. However, the fibrous activated carbon knitted fabric of Patent Document 1 is ribbed or double-sided knitted, and it is difficult to reduce the weight. On the other hand, the fibrous activated carbon multilayer fabric of Patent Document 2 has low stretchability due to its structure and is inferior in wearing comfort.

Therefore, the present invention has been made to solve the above problems, and its purpose is to provide a fibrous activated carbon that is lightweight, highly breathable, and stretchable.

The inventors of the present invention have conducted intensive studies to solve the above problems, and have arrived at the present invention. That is, the present invention is as follows.
1. A fibrous activated carbon knitted fabric having a warp knitted fabric and having an absolute dry mass of 30 g/m ² or more and less than 80 g/m ² .
2. The fibrous activated carbon knitted fabric as described in 1 above, having an air permeability of 300 cm ³ /cm ² ·s or more and 5000 cm ³ /cm ² ·s or less.
3. The fibrous activated carbon knitted fabric according to item 1 or 2 above, which has an elongation of 5% or more in the warp and 30% or more in the width.
4. 4. The fibrous activated carbon knitted fabric according to any one of 1 to 3 above, wherein the knitted fabric is a single raschel knit.
5. A protective material using the fibrous activated carbon knitted fabric according to any one of 1 to 4 above.
6. Protective clothing using the protective material described in 5 above.

The fibrous activated carbon knitted fabric of the present invention is a knitted fabric produced by warp knitting, and has an absolute dry mass of 30 g/m ² or more and less than 80 g/m ² , so it is lightweight, has high air permeability, and has elasticity. A fibrous activated carbon knitted fabric can be provided. Furthermore, stable shrinkage even during continuous carbonization and activation steps during industrial production makes it possible to provide a fibrous activated carbon knitted fabric with excellent quality and quality.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following, and can be implemented with appropriate changes within the scope that fits the spirit of the above and below. All of them are included within the technical scope of the present invention.

In the fibrous activated carbon knitted fabric of the present invention, the knitted fabric is warp knitted. Therefore, in this specification, fibrous activated carbon having a warp-knitted fabric, fibrous activated carbon warp-knitted fabric, or warp-knitted fibrous activated carbon may be referred to.
The fibrous activated carbon warp-knitted fabric of the present invention has an absolute dry mass (positive weight) based on JIS L1096 of 30 g/m ² or more and less than 80 g/m ² , preferably 50 g/m ² or more and 75 g/m ² or less. If it is less than 30 g/m ² , the adsorption performance will be low (for example, toluene adsorption performance will be less than 15 g/m ² ), and when used as a filter or protective clothing, it will not be able to exhibit sufficient practical performance. Moreover, if it is 80 g/m ² or more, it is difficult to obtain the benefit of weight reduction, and when used in protective clothing, it becomes heavy and has poor breathability.

The fibrous activated carbon warp-knitted fabric of the present invention preferably has an elongation of 5% or more in the vertical direction and 30% or more in the horizontal direction. More preferably, the elongation is 15% or more in the vertical direction and 30% or less in the horizontal direction. There is no particular upper limit. If it is less than 5% in the vertical direction and 30% in the horizontal direction, it is not preferable because it becomes uncomfortable to wear when used for protective clothing.

The fibrous activated carbon warp-knitted fabric of the present invention has an air permeability of 300 cm ³ /cm ² ·s or more and 5000 cm ³ /cm ² ·s or less when measured by the method described in JIS L1096 "Fabric testing method for woven and knitted fabrics" It is preferable that More preferably, it is 330 cm ³ /cm ² ·s or more and 3000 cm ³ /cm ² ·s or less. If it is less than 300 cm ³ /cm ² ·s, there may be problems such as increased pressure loss when used as a filter or the like, and a decrease in the feeling of wearing when used as protective clothing. If it exceeds 5000 cm ³ /cm ² ·s, knitting may not be possible.

The fibrous activated carbon warp-knitted fabric of the present invention has a thickness of 0.3 mm or more and 2.0 mm or less when measured by applying a pressure of 0.7 kPa as described in Section 8.4 of JIS L1096 "Fabric Testing Methods for Woven and Knitted Fabrics". is preferred. More preferably, it is 0.5 mm or more and 1.0 mm or less. If it is less than 0.3 mm, breathability becomes low, which is undesirable, and if it exceeds 2.0 mm, when used in protective clothing, it increases the physiological burden, which is undesirable.

The adsorption performance of the fibrous activated carbon warp knitted material of the present invention is 15 g/m ² or more and 60 g/m ² or less (25°C, 1/2 10 dilution condition), preferably 25 g/m ² or more and 50 g/m ² or less. If it is less than 15 g/m ² , the practical performance may not be sufficiently exhibited when used as a filter or protective clothing. On the other hand, if it exceeds 50 g/m ² and is used as clothing such as protective clothing, the weight may increase the physiological burden when worn.

When processing the fibrous activated carbon warp-knitted fabric of the present invention according to the purpose, for example, when laminating it with other fiber aggregates such as woven or knitted fabrics or non-woven fabrics, it is necessary to mechanically process the fibrous activated carbon warp-knitted fabric when attempting to process it industrially. Stress may be applied and tearing may occur. In order to prevent this, it is necessary that the tensile strength is at least 3N/5cm or more according to the method described in JIS L1096. If it is less than this, the productivity will be significantly reduced when performing lamination processing or other processing for commercialization, making it impractical.

In order to obtain such a warp-knitted fibrous activated carbon material with high tensile strength, it is desirable that the precursor fiber is a phenolic fiber. Cellulose-based, pitch-based, and PAN-based fibers are also known as precursor fibers for fibrous activated carbon. When cellulose fibers are used as the entire precursor, fibrous activated carbon having a specific surface area that exhibits sufficient adsorption performance can be obtained by carbonization and activation, but there are problems in that the yield is low and the shrinkage rate is large. When PAN-based fibers are used as precursor fibers, relatively high fabric strength can be obtained, but it is difficult to obtain fibrous activated carbon with high adsorption performance. When pitch-based fibers are used, strength and adsorption performance that are intermediate between those of cellulose-based fibers and PAN-based fibers can be obtained, but both characteristics are not necessarily satisfied.

Furthermore, the fibrous activated carbon warp knitted fabric of the present invention preferably has a specific surface area of 1000 m ² /g or more and 3000 m ² /g or less as determined by the BET method in order to exhibit adsorption performance.

Because sheet-like fibrous activated carbon has excellent flexibility, it is used as various filters and elements to adsorb various organic solvent gases. As mentioned above, the forming method is to make the raw organic fiber into a knitted fabric and then carbonize and activate it, or to carbonize and activate the raw organic fiber to obtain fibrous activated carbon and then process it into a non-woven fabric such as felt. There are several methods. In terms of flexibility, fibrous activated carbon sheets in the form of knitted fabrics, especially weft-knitted ones, are excellent, but on the other hand, they have low strength and have been observed to fall off due to tearing, abrasion, etc. On the other hand, although woven fabrics have high strength, they have poor elasticity and flexibility. Therefore, by warp-knitting the structure, a fibrous activated carbon sheet with a good balance of weight, strength, flexibility, air permeability, adsorption performance, etc. can be obtained. Regarding the process of obtaining the fibrous activated carbon warp-knitted fabric, it is preferable to first warp-knit the threads of the precursor fibers and then carbonize and activate them to obtain the activated carbon warp-knitted fabric. This is actually impossible industrially because of the weak

The fibrous activated carbon warp-knitted fabric of the present invention can be produced by making a precursor fiber into a warp-knitting fabric, and then carbonizing and activating it. The thread form of the precursor fiber may be either a spun thread obtained from staples or a filament thread, or may be a mixed thread obtained by mixing both. The fineness of single fibers is 1.1 dtex to 5.5 dtex, and the fineness of twisted threads is 197 dtex or more, preferably 295 to 885 dtex. In the case of 197 dtex or less, the density of the fibrous activated carbon warp knitted material after knitting, carbonization and activation becomes dense and sufficient air permeability cannot be obtained. In addition, the lack of flexibility may lead to tearing or tearing during post-processing or use.

When converting the precursor warp knitted fabric obtained in this way into activated carbon, it can be obtained by performing a carbonization and activation process in a batch or continuous process, but the fabric properties and adsorption performance of the fibrous activated carbon warp knitted fabric are uniform. In consideration of obtaining properties and industrial productivity, it is preferable to carry out carbonization and activation continuously. The precursor warp knitted fabric is carbonized in an inert atmosphere at a temperature of 350°C or higher and 1000°C or lower, and then activated in an active atmosphere containing water vapor, oxygen, carbon dioxide, etc. that react with carbon at a temperature of 500°C or higher and 1000°C or lower. Activated carbonization. Further, depending on the case, it is also possible to perform carbonization and activation simultaneously by controlling the atmospheric conditions. Note that if the maximum temperature during activation treatment, that is, activated carbonization, is 1000°C or higher, wrinkles may occur due to abnormal shrinkage, etc., so it is preferable that the maximum temperature is 1000°C or lower. Thereby, the fibrous activated carbon warp knitted fabric of the present invention is obtained.

The fibrous activated carbon warp knitted fabric of the present invention has excellent processability such as lamination processing, is durable against tension and bending, is lightweight, has good handling properties, has high air permeability, and has excellent organic gas adsorption performance. ing. Furthermore, for this reason, medical supplies such as masks, deodorizing pads, and deodorizing sheets, protective clothing that protects the body from harmful gases, various air purifiers, various adsorption elements used in liquid phase, electrical reaction fields such as various battery electrodes, etc. It can be suitably used for electrodes for electric baths, etc. Furthermore, the fibrous activated carbon warp-knitted fabric of the present invention may be used in combination with other sheet materials or molded products by laminating, pasting, etc.

Hereinafter, the present invention will be described in detail based on Examples. However, the following examples do not limit the present invention, and all modifications and implementations within the scope of the above and below-mentioned gist are included within the technical scope of the present invention.

The method for measuring each characteristic value measured in Examples and Comparative Examples is as follows. The mass per unit when dry (absolute dry mass), mass per unit when standard, thickness, bulk density, air permeability, and tensile strength are based on JIS L1096, and the toluene adsorption performance of fibrous activated carbon is: Compliant with JIS K1477.

<Example 1>
Using Gunei Chemical's phenolic fiber (KY-84) with a single fiber fineness of 2.2 dtex and a filament fineness of 590 dtex, a single raschel knitted fabric with a density of 8 courses/inch and 11 wales/inch was knitted as a precursor. It was knitted in the body warp. This precursor warp knitted fabric has a basis weight of 150 g/m ² , a thickness of 1.2 mm, an air permeability of 500 cm ³ /cm ² s, a tensile strength of 200 N/5 cm in the vertical direction, 130 N/5 cm in the horizontal direction, and an elongation rate. It was 30% in the vertical direction and 70% in the horizontal direction. This precursor warp-knitted fabric was carbonized from room temperature to 890°C for 30 minutes in an inert atmosphere, and then activated at a temperature of 910°C for 90 minutes in an atmosphere containing 12 wt% water vapor. The obtained warp-knitted fibrous activated carbon had an absolutely dry mass of 70 g/m ² , a thickness of 0.8 mm, an air permeability of 360 cm ³ /cm ² s, and a tensile strength of 8 N/5 cm in the vertical direction and 8 N/5 cm in the horizontal direction. The direction was 4N/5cm, and the elongation rate was 5% in the vertical direction and 60% in the horizontal direction. Further, the toluene adsorption performance was 40 g/m ² and the BET specific surface area was 1680 m ² /g, which was a high adsorption performance.

<Comparative example 1>
A milled knitted fabric was knitted using a 22-gauge double-sided circular knitting machine using a phenolic fiber (KY-04) manufactured by Gunei Chemical Co., Ltd. with a single fiber fineness of 2.2 dtex and a filament fineness of 295 dtex to obtain a precursor flat knitted fabric. This precursor flat knitted fabric has a basis weight of 180 g/m ² , a thickness of 1.60 mm, an air permeability of 300 cm ³ /cm ² s, a tensile strength of 190 N/5 cm in the vertical direction, 240 N/5 cm in the horizontal direction, and an elongation rate. It was 130% in the vertical direction and 140% in the horizontal direction. This knitted fabric was carbonized from room temperature to 890°C for 30 minutes in an inert atmosphere, and then activated at a temperature of 890°C for 90 minutes in an atmosphere containing 12 wt% water vapor. The obtained flat-knitted fibrous activated carbon had an absolute dry mass of 115 g/m ² , a thickness of 1.1 mm, an air permeability of 340 cm ³ /cm ² s, and a tensile strength of 20 N/5 cm in the vertical direction and 5 cm in the horizontal direction. 10N/5cm, and the elongation rate was 30% in the vertical direction and 110% in the horizontal direction. Further, the toluene adsorption performance was 54 g/m ² and the BET specific surface area was 1450 m ² /g, which was a high adsorption performance.

<Comparative example 2>
A phenolic fiber (KY-04) manufactured by Gunei Chemical Co., Ltd. with a single fiber fineness of 2.2 dtex and a filament fineness of 295 dtex was used, and an extremely coarse milled fabric was knitted using a 12 gauge circular knitting machine to obtain a precursor flat knitted fabric. This precursor flat knitted fabric has a basis weight of 152 g/m ² , a thickness of 1.20 mm, an air permeability of 270 cm ³ /cm ² s, a tensile strength of 130 N/5 cm in the vertical direction, 65 N/5 cm in the horizontal direction, and an elongation rate. It was 90% in the vertical direction and 285% in the horizontal direction. This precursor flat knitted material was carbonized in an inert atmosphere from room temperature to 890°C for 30 minutes, and then activated at a temperature of 910°C for 90 minutes in an atmosphere containing 12 wt % water vapor. The obtained flat-knitted fibrous activated carbon had an absolutely dry mass of 90 g/m ² , a thickness of 1.0 mm, an air permeability of 270 cm ³ /cm ² s, and a tensile strength of 20 N/5 cm in the vertical direction and 20 N/5 cm in the horizontal direction. The direction was 10 N/5 cm, and the elongation rate was 30% in the vertical direction and 110% in the horizontal direction. Further, the toluene adsorption performance was 44 g/m ² and the BET specific surface area was 1450 m ² /g, which showed high adsorption performance.

<Comparative example 3>
Gunei Chemical's phenolic fiber (KY-84) with a single fiber fineness of 2.2 dtex and a filament fineness of 590 dtex is used, and the driving density is 11, 10, 11 fibers/inch in warp, 10, 11, 10 fibers/inch in weft. A triple-ply fabric was woven to obtain a precursor fabric. This precursor fabric has a basis weight of 155 g/m ² , a thickness of 1.1 mm, an air permeability of 310 cm ³ /cm ² s, a tensile strength of 290 N/5 cm in the vertical direction, 280 N/5 cm in the horizontal direction, and an elongation rate of It was 12% in the vertical direction and 11% in the horizontal direction. This precursor fabric was carbonized from room temperature to 890°C for 30 minutes in an inert atmosphere, and then activated at a temperature of 910°C for 90 minutes in an atmosphere containing 12 wt% water vapor. The obtained textile-like fibrous activated carbon has an absolutely dry mass of 95 g/m ² , a thickness of 1.1 mm, and an air permeability of 160 cm ³ /cm ² s, and has a tensile strength of 45 N/5 cm in the vertical direction and 45 N/5 cm in the horizontal direction. 36N/5cm, and the elongation rate was 15% in the vertical direction and 25% in the horizontal direction. Further, the toluene adsorption performance was 50 g/m ² and the BET specific surface area was 1650 m ² /g, which was a high adsorption performance.

Table 1 shows that the warp-knitted fibrous activated carbon knitted fabric of Example 1 is lightweight, has high air permeability, and has elasticity.

The fibrous activated carbon warp knitted fabric of the present invention can be used in medical products such as masks, deodorizing pads, and deodorizing sheets, protective clothing that protects the body from harmful gases, various air purifiers, various adsorption elements used in liquid phase, and electrical reaction fields. For example, it can be suitably used for various battery electrodes, electric tank electrodes, and the like.

Claims (6)

A fibrous activated carbon knitted fabric having a warp knitted fabric and having an absolute dry mass of 30 g/m ² or more and less than 80 g/m ² . The fibrous activated carbon knitted fabric according to claim 1, having an air permeability of 300 cm ³ /cm ² ·s or more and 5000 cm ³ /cm ² ·s or less. The fibrous activated carbon knitted fabric according to claim 1 or 2, characterized in that the elongation is 5% or more in the warp and 30% or more in the width. The fibrous activated carbon knitted fabric according to any one of claims 1 to 3, wherein the knitted fabric is a single raschel knit. A protective material using the fibrous activated carbon knitted fabric according to any one of claims 1 to 4. Protective clothing using the protective material according to claim 5.