JP2003290654A - Active carbon fiber, manufacture method therefor, for cartridge water-cleaning device and water-cleaning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active carbon fiber in which an adsorption speed is large and which is excellent in an adsorption of a macro-molecule; a manufacture method therefor; and a water-cleaning device. <P>SOLUTION: The problem can be solved by the active carbon fiber in which an average roughness of the surface is 5 nm or higher. The active carbon fiber can be manufactured by a manufacturing method of the active carbon fiber in which a polyvinyl alcohol fiber is preferably used as a material and a draw ratio of the active carbon fiber is 3 to 10 times in terms of a spinning material of a polyvinyl alcohol resin. The active carbon fiber is preferably molded to a cartridge and is used for the water-cleaning device. <P>COPYRIGHT: (C)2004,JPO

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, a method for producing the same, a water purifier cartridge and a water purifier. More specifically, the present invention relates to an activated carbon fiber having a controlled pore distribution, excellent adsorption of macromolecules, a high adsorption rate, and controlled surface irregularities, a method for producing the same, a water purifier cartridge, and a water purifier. The activated carbon fiber of the present invention is preferably used for various electrode materials, heat insulating materials, adsorbent materials, flameproof materials, etc., but especially, water purification, water treatment,
Suitable for adsorbing applications such as air purification, solvent recovery, gas adsorption, decolorization, tobacco filters, clean room filters, blood purification, secondary batteries, electrolytic capacitors,
It is also useful for electrodes such as electric double layer capacitors.

[0002]

2. Description of the Related Art Activated carbon fibers have advantages that they have a significantly larger macroscopic contact area, have a faster adsorption rate, do not generate dust, and have a lower pressure loss than granular or powdery activated carbon. Taking advantage of this advantage, it is preferably used in adsorption fields such as water purifiers, air purifiers, and solvent recovery devices.

Further, in the field of electric materials, for example, an electric double layer capacitor, a cloth electrode does not need a binder and is active as compared with a sheet electrode which is a mixture with a binder composed of granular or powdery activated carbon. Since carbon fibers are continuously connected, it has good electrical conductivity and low resistance, and it has no long-term stability because it is not deteriorated by a binder. In recent years, it has been an electrode material for electric double layer capacitors. Even in the spotlight.

As a raw material for such activated carbon fiber,
Pitch-based fibers, phenol resin-based fibers, rayon-based fibers, acrylic fibers, vinylon-based fibers, etc. have been known so far, and many patent applications have been filed regarding a method for producing activated carbon fibers using these as raw materials. Pitch-based activated carbon fibers, phenol resin-based activated carbon fibers, rayon-based activated carbon fibers, acrylic activated carbon fibers and the like have already been put into practical use as adsorbents.

However, from the viewpoint of the activated carbon fiber as an adsorbent, the adsorption rate and the selective adsorption performance are still insufficient, and further improvement of the adsorption rate and provision of the selective adsorption performance are desired. For example, when using activated carbon fibers in a water purifier, if the adsorption rate is high, the processing time can be shortened and the apparatus can be downsized, and there is a strong demand for improved performance.

[0006] Japanese Patent Laid-Open No. 61-296124 is known as the only known technique for controlling the irregularities on the surface of activated carbon fiber. The disclosure of the publication is the degree of irregularity on the micrometer scale. Control, and control at the nanometer scale is not mentioned at all. Therefore, so far, regarding the selective adsorption performance, from activated carbon fibers having large pores capable of selectively adsorbing macromolecules such as endotoxin and protein, for example, having large pores in the vicinity of 20 to 50Å. No such adsorbent has been found, and there is no activated carbon fiber in which surface irregularities, surface hydrophobicity, and pore structure are controlled and which has an excellent adsorption rate.

[0007]

The first problem to be solved by the present invention is to provide an activated carbon fiber having a high adsorption rate and a method for producing the same, and particularly activated carbon excellent in adsorption of macromolecules. It is to provide a fiber and a manufacturing method thereof. A second problem to be solved by the present invention is to provide a water purifier cartridge in which these activated carbon fibers are molded, and a third problem is to provide a water purifier using the cartridge. Is.

[0008]

[Means for Solving the Problems] In order to obtain an activated carbon fiber which has a high adsorption rate and is particularly excellent in adsorbing macromolecules, the present inventors control the surface irregularities on a nanoscale to increase the surface area. As a result of intensive investigations focusing on the importance of the fact, the present invention has been achieved. That is, the present invention is
The activated carbon fiber has an average surface roughness of 5 nm or more.

Another invention of the present invention is to use polyvinyl alcohol fiber as a raw material and convert the spinning raw yarn of polyvinyl alcohol resin into a stretch ratio of 3 of activated carbon fiber.
It is a method for producing activated carbon fiber in which the amount is 10 times.

Another aspect of the present invention is a water purifier cartridge formed by molding these activated carbon fibers, and a water purifier using the cartridge.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the average roughness of the surface of activated carbon fiber is important, and if the average roughness of the surface is too small, the effect of improving the adsorption rate is small when used as an adsorbent. , Average roughness of activated carbon fiber surface is 5n
It must be m or more. Further, when the average roughness of the activated carbon fiber surface is increased, the surface area is increased and the adsorption rate tends to be improved, but the bulk density is reduced, which may cause a reduction in the strength of the activated carbon fiber. ,
The average roughness of the surface of the activated carbon fiber is preferably 5 nm to 1 μm, and more preferably 15 nm to 500 nm. The average roughness of the surface of the activated carbon fiber can be measured by, for example, an atomic force microscope device as described later.

When the average roughness of the activated carbon fiber surface is larger than 1 μm, the effect can be improved by controlling the degree of irregularity on the micrometer scale. That is, draw a circumscribed circle on the irregular cross section,
The cross-sectional solidity (100% is a perfect circle) determined by the ratio of the actual cross-sectional area to the area of the circle is 40 to 1
By setting the content in the range of 00%, the decrease in bulk density can be suppressed and the effect can be improved. More preferably, the cross-sectional solidity is in the range of 60 to 100%. The range of cross-sectional integrity can be adjusted by changing the spinning nozzle.

To further improve the adsorption rate, 250
It is effective to use activated carbon fibers whose weight loss after heat treatment at ℃ is 0.03% by weight or less. If the weight loss after heat treatment at 250 ° C exceeds 0.03%, the adsorption rate may decrease, and if the weight loss after heat treatment at 250 ° C is less than 0.01%, it may be difficult to produce. It will be very difficult. As described above, it is not always possible to clearly explain the reason why the adsorption rate is improved by reducing the weight loss, but the large weight loss means that hydrophilic substances such as moisture in the air have already been adsorbed in the pores. This means that the surface of the pores is hydrophilized to some extent. That is, most of the substances to be adsorbed and removed are organic substances such as trihalomethanes, aldehydes, aromatics, and proteins, but if the surface is made hydrophilic, the adsorption rate of these organic substances decreases. It is supposed to do.

The state of the activated carbon fiber surface is also important for the adsorption rate. In order to impart excellent performance to the adsorption of macromolecules, the pore distribution is controlled so that the pore radius is 20 to 5
The presence of many pores in the range of 0Å can improve the adsorption rate of macromolecules such as proteins and endotoxins, which is preferable.

When the volume of pores having a pore distribution in the range of 20 to 50Å is much smaller than the volume occupied by pores having a radius of 100Å or less, the effect of improving the adsorption rate of macromolecules is improved. On the contrary, if it is too large, activation becomes necessary for a long time, it becomes difficult to produce, and the yield tends to be low and the strength tends to be low. , The volume of pores in the range of 20 to 50 Å of the pore radius measured by the water vapor adsorption method is 10 of the volume occupied by the pores having a radius of 100 Å or less.
%, It is preferable to control the pore distribution so as to be not less than
It is more preferable to be 10% or more and 80% or less.

As the raw material of the activated carbon fiber of the present invention, the pitch type fiber, the phenol resin type fiber, the rayon type fiber, the acrylic type fiber, the polyvinyl alcohol type fiber and the like as mentioned above can be used. It is preferable to use polyvinyl alcohol fiber (hereinafter, polyvinyl alcohol is abbreviated as PVA). When the activated carbon fiber of the present invention is used as an adsorbent, its form is not particularly limited, and it can be used in the form of cloth, felt, paper, cylinder, honeycomb, or other shaped bodies. The size, shape, etc. of the molded body may be appropriately selected according to the intended use. The manufacturing method of the molded body is not particularly limited, but when it is used in the form of cloth, for example, the raw material fibers may be woven into cloth, activated carbon fibers may be woven, or the intermediate may be woven. . From the perspective of fiber strength,
It is preferable to weave the raw material fibers.

When used in the felt form, it is preferable to process the raw material fibers as in the cloth form. With respect to a molded product that requires a binder such as a paper-like or cylindrical-like product, it is common to use a cut fiber of activated carbon fiber and a known binder for the production. Increase the adsorption rate,
In addition, in order to increase the adsorption amount, it is preferable to reduce the binder amount as much as possible. With the activated carbon fiber of the present invention, even if the amount of the binder is reduced, a high-quality molded article excellent as an adsorbent is obtained, which is also effective for improving the adsorption rate. In the adsorbent of the present invention, the reason why the amount of binder can be decreased is considered to be that the increase in the friction coefficient due to the irregularities on the surface of the activated carbon fiber contributes to it.
It is presumed that the amount of binder can be reduced by controlling the unevenness of the activated carbon fiber surface.

The method for producing the activated carbon fiber of the present invention is not particularly limited, but from the viewpoint of easy control of nano-sized irregularities, PVA-based fiber is used as the raw material and converted from the spinning raw yarn of PVA-based resin, It is preferable to employ a method of producing activated carbon fibers so that the stretch ratio of the activated carbon fibers is in the range of 2 to 6 times. The activated carbon fiber having an average surface roughness of 5 nm or more is easily produced by controlling the drawing ratio of the activated carbon fiber to be in the range of 2 to 6 in terms of the spinning raw yarn of the PVA resin. be able to. It is more preferable to use PVA fibers to which a dehydrating agent is attached as a raw material.

Next, a method for producing activated carbon fibers by using PVA as a raw material for activated carbon fibers will be described.
The PVA-based fiber used in the present invention is obtained from a PVA-based resin obtained by saponifying a vinyl acetate homopolymer or a copolymer thereof which is usually used in the production of PVA. Further, it is obtained by decomposing a bulky vinyl ester having a side chain such as vinyl pivalate or vinyl formate or a vinyl ester having high polarity, or a homopolymer or copolymer of vinyl ether such as t-butyl vinyl ether, trimethylsilyl vinyl ether or benzyl vinyl ether. The PVA-based resin may be used as a raw material for the fiber.

Here, the comonomer unit of the copolymer can be divided into a unit that produces a vinyl alcohol unit by saponification or decomposition and a unit other than the unit. The latter comonomer unit is mainly for modification. It is copolymerized and is used within a range not impairing the gist of the present invention. Examples of such a unit include olefins such as ethylene, propylene, 1-butene, and isobutene,
Acrylic acid and its salts, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate,
Acrylic esters such as t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, methacrylic acid and its salts, methyl methacrylate, ethyl methacrylate, n methacrylate
-Propyl, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-methacrylic acid
-Methacrylic acid esters such as butyl, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, acrylamide, N-methyl acrylamide, N-ethyl acrylamide, N, N-dimethyl acrylamide, diacetyl acrylamide Acrylamidopropanesulfonic acid and its salts, acrylamidopropyldimethylamine and its salts and quaternary salts, acrylamide derivatives such as N-methylolacrylamide and its derivatives, methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N, N-dimethyl methacrylamide, diacetone methacrylamide, methacrylamide propane sulfonic acid and its salts, methacrylamide propyldimethylamine and its salts and quaternary salts,
Methacrylamide derivatives such as N-methylol methacrylamide and its derivatives, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, i-butyl vinyl ether, t
-Butyl vinyl ether, benzyl vinyl ether, dodecyl vinyl ether, vinyl ethers such as stearyl vinyl ether, acrylonitrile, nitriles such as methacrylonitrile, vinyl chloride, vinylidene chloride, vinyl fluoride, vinyl halides such as vinylidene fluoride, allyl acetate, Examples thereof include allyl compounds such as allyl chloride, maleic acid and salts and esters thereof, itaconic acid and salts and esters thereof, vinylsilyl compounds such as vinyltrimethoxysilane, and isopropenyl acetate.

The degree of saponification of the PVA resin is preferably 70 mol% or more, more preferably 90 to 99.99 mol%. Here, the degree of saponification is the ratio of vinyl alcohol units after saponification to units that can be converted to vinyl alcohol units by saponification in a vinyl acetate homopolymer or copolymer, and the residue is vinyl acetate. It is a unit.
The degree of polymerization of the PVA-based resin is preferably 1000 or more, more preferably 1700 or more. However, PVA-based resins having a degree of polymerization of more than 30,000 are generally difficult to produce, and are not necessarily suitable from the viewpoint of industrial production.

The method for producing the PVA fiber is not particularly limited, but a known wet spinning method, dry wet spinning method or dry spinning method can be adopted. What is the wet spinning method?
This is a method in which a spinning solution containing a polymer solution obtained by dissolving a PVA-based resin in an organic solvent or an aqueous solution obtained by dissolving the PVA-based resin in water is directly spun from a spinning nozzle into a solidifying bath, which is a dry-wet spinning method. Is a spinning method in which a gas space (air-gap) such as air or an inert gas is provided between a spinning nozzle and a solidifying bath, the gas is caused to travel for a specific distance, and then spun into the solidifying bath. .

The wet spinning method in which the spinning nozzle is brought into direct contact with the solidifying bath to perform spinning is suitable for spinning using a multi-hole nozzle because fibers can be spun without sticking even if the nozzle hole pitch is narrowed. On the other hand, in the case of the dry-wet spinning method in which an air gap is provided between the solidification bath and the spinning nozzle, and spinning is performed from the spinning nozzle through the gas, high-speed spinning is achieved due to the large elongation in the air gap portion. Are suitable. The dry spinning method is a spinning method in which a spinning dope, which is an aqueous solution obtained by dissolving a PVA-based resin in water, is spun directly into a gas from a spinning nozzle, and does not require a solidifying bath. . The spinning method as described above may be appropriately selected and adopted according to the purpose and use.

First, the wet spinning method and the dry wet spinning method will be described. Examples of the solvent for the PVA-based resin that constitutes the spinning solution include polyhydric alcohols such as glycerin, ethylene glycol, diethylene glycol, triethylene glycol, butanediol, and organic solvents selected from dimethyl sulfoxide, dimethylformamide, diethylenetriamine, or the like. It is preferable to use a mixed solvent of two or more kinds, and further a mixed solvent of these organic solvents and water. The spinning dope is obtained by dissolving the PVA resin in these solvents.

The concentration of the PVA-based resin in the spinning dope varies depending on the degree of polymerization, but if the concentration of the PVA-based resin is too high, the viscosity of the dope may become high and stable spinning may become difficult. If the concentration is too low, the productivity tends to decrease, and the variation in the single fiber thickness (denier unevenness) is likely to occur, so 5 to 30% by weight,
It is particularly preferably 10 to 20% by weight. The temperature of the spinning dope is generally 80 to 230 ° C.

If desired, other additives may be added to the spinning dope. For example, in order to extend the life of the spinneret during spinning and enhance the stability of the stretching process, one or more surfactants, inorganic decomposition inhibitors, dyes, pigments, etc. may be added to the spinning dope. In this case, the addition rate is preferably 20% by weight or less, particularly 0.1 to 5% by weight in order to suppress defective dewatering and solidification of Ishino. The type of surfactant may be any of nonionic type, anionic type, cationic type and amphoteric type, but when two or more types are used in combination, precipitation such as anionic type and cationic type occurs. Such a combination is not preferable. It is particularly preferable to use a nonionic surfactant.

It is also possible to form a crosslinked structure at the time of discharging from the spinneret into the solidifying bath to homogenize the structure of the fiber cross section. For example, boric acid or borate salts may be added to the stock solution. Can form a crosslinked structure. In this case, the boric acid or borate contained in the spinning dope is 0.
It is desirable to add it in an amount of 03 to 0.2% by weight, preferably 0.05 to 0.15% by weight. The spinning dope thus obtained is spun in a solidifying bath through a spinning nozzle by a wet spinning method or a dry wet spinning method.

As the solidifying liquid for solidifying the spinning dope and making it into fibers, there are solvent-based or aqueous solidifying liquids. The solvent-based solidifying liquid is preferably an organic solvent having solidifying ability with respect to PVA, such as alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone. From the standpoint of spinnability, fiber performance, etc., the concentration of the stock solution for spinning in the solidification bath is 20 to 70% by weight, and further 25 to
It is more preferably 65% by weight, and the composition weight ratio of the solidifying solution / spinning stock solution solvent is preferably 25/75 to 85/15. Further, other additives may be added as long as the effects of the present invention are not impaired.

The temperature of the solidifying bath is preferably 30 ° C. or lower, more preferably 20 ° C. or lower, further preferably 15 ° C. or lower, from the viewpoint of further reducing the solidification reaction rate and forming a sufficiently uniform gel structure inside the fiber. Is preferred. By adopting such a method, fibers having a high degree of crystallinity can be obtained even when solidification is uniform in the cross-sectional direction and heat treatment or the like is not performed. From the viewpoint of reducing sticking between fibers and facilitating subsequent dry heat drawing, it is preferable to wet draw 2 to 10 times with the organic solvent contained in the Shinoshino that has been separated from the solidifying bath. It is preferable to perform wet stretching in the temperature range of -60 ° C.

Next, the fiber is immersed in an extraction bath to extract the solvent. As the extractant, alcohols such as methanol, ethanol and propanol, acetone, methyl ethyl ketone, ether and water can be used. Then, if necessary, an oil agent or the like may be applied and dried. From the viewpoint of increasing the strength of the PVA-based fiber, which is the raw material of the activated carbon, it is preferable to further carry out dry heat drawing, and it is particularly preferable to carry out dry heat drawing so that the total draw ratio is 6 times or more, preferably 8 times or more. . The total draw ratio is represented by the product of the wet draw ratio and the dry heat draw ratio.

When the stock solution for spinning is an aqueous solution of PVA resin, the aqueous solidifying solution is not particularly limited as long as it has a solidifying ability for the stock solution for spinning, but in view of processability and cost, water is used as a solvent. It is preferable to use a solidifying solution of Specifically, an aqueous solution of a salt having a dehydrating ability such as sodium sulfate (Glauber's salt), ammonium sulfate, and sodium carbonate is used. The concentration of the aqueous solution can be selected from 300 g / liter (L) or more to the saturated concentration, but it is preferable that the concentration be as close to the saturated concentration as the dehydration and solidification ability is high. Among them, it is preferable to use a saturated aqueous solution solidifying bath from the viewpoints of processability and cost. The temperature of the solidification bath is 20 to 70 ° C, especially 3
The temperature is preferably 0 to 50 ° C. When boric acid and borate salts are added to the spinning dope, the spinning dope is discharged into the solidifying bath to contain a substance such as sodium hydroxide for making the solidifying bath alkaline in order to develop a crosslinked structure. There is a need. For example, in the case of sodium hydroxide, the concentration in the solidifying bath is preferably 0.5 to 3% by weight.

The spinning dope discharged from the spinneret into the solidifying bath is dehydrated and solidified in the solidifying bath to form a yarn, and then separated from the solidifying bath to perform roller stretching about 1 to 4 times. Then, when boric acid or the like is added to the spinning dope and sodium hydroxide or the like is added to the solidification bath to develop a crosslinked structure, for example, sulfuric acid or the like for neutralizing and removing the alkaline compound adhering to the thread is contained. It is necessary to pass a neutralization bath containing the acid of. In this case, the concentration of sulfuric acid is 5
About 10 to 10% by weight is preferable. Then, in order to enhance the morphological stabilization of the Shinoshino, it is advisable to carry out wet heat stretching in a saturated aqueous solution bath of high temperature consisting of salts having the same dehydrating ability as the solidifying solution. The bath temperature is preferably 90 ° C. or higher, and the wet heat draw ratio is preferably about 1 to 3.

Next, in order to remove the salts, acids, boric acid, etc. adhering to the Shinoshino by washing, the Shinoshino is introduced into a water washing tank and washed in running water until these contents in the fiber can be removed.
In the washing step, it is preferable to wash the thread under tension from the viewpoint of selectively removing inorganic salts on the fiber surface and inside the fiber, and from more effectively suppressing the swelling of the fiber. It is preferable to keep the tension constant. At this time, ultrasonic vibration may be applied to the Shinobu in the bath or the Shinobu may be moved up and down in the bath in order to selectively remove the inorganic salts on the fiber surface more quickly. From the viewpoint of effectively preventing swelling and sticking of fibers, the temperature of the cleaning liquid is 1
The temperature is preferably 0 to 70 ° C., and particularly preferably controlled to a constant temperature of 20 to 50 ° C.

If desired, an oil agent for preventing sticking may be attached to the thread after the washing step in order to suppress sticking between fibers which tends to occur after the drying step. As the attachment method, a conventionally known method, for example, a method of impregnating an oil agent tank with the oil agent to apply the oil agent, a method of contacting the roller surface with the oil agent with the thread agent, and the like can be adopted. As an oil agent component, it has good adhesion to PVA-based fibers and a drying temperature (100-
A material that does not solidify even at 150 ° C. and does not increase the inter-fiber friction coefficient of the PVA-based fiber, for example, a paraffin-based oil agent is preferable. Adhesion rate of oil agent is 1.2% by weight or less / P
VA, more preferably 0.8% by weight or less, and particularly preferably 0 to 0.5% by weight / PVA.

Next, the wet thread is dried. 80 drying
It is preferably carried out at a temperature of about 150 to 150 ° C., particularly about 100 to 140 ° C. Itoshino is dried, then stretched and wound up. The water content of Itoshino introduced into the drying process is 80 to 3
About 00% by weight / PVA, especially 90 to 200% by weight /
PVA, more preferably 100 to 150% by weight, is preferable in terms of prevention of sticking and drying efficiency. It is preferable that the moisture content of the dried shinobi is 1% / PVA or less.

After the drying step, the thread is further stretched to obtain a PVA fiber having excellent mechanical performance. The stretching method is not particularly limited, and generally applied stretching is adopted. The total draw ratio is 6 times or more, especially 7 times or more, and further 8
It is preferably double or more. Further, after stretching, various treatments such as heat treatment, shrinkage treatment, oil agent imparting treatment, and acetalization treatment may be carried out if necessary.

Next, the dry spinning method will be described. First, a PVA-based resin is made into a water-containing chip having a concentration of 40 to 60% by weight, melted by heating with an extruder, and defoamed. The temperature of the spinning dope is preferably 90 to 140 ° C. Dry spinning is performed by pressurizing such a PVA spinning stock solution and discharging it into the air from the nozzle hole. The nozzle hole may have a circular shape or any other shape other than the circular shape, such as a flat shape, a cross shape, a T shape, a Y shape, an L shape, a triangular shape, a square shape, or a star shape. However, the above-mentioned T-shaped, Y-shaped, L-shaped and other modified cross-section fibers may be broken during the production, but even if the fibers are broken, the purpose and effect of the present invention are not significantly impaired.

After that, the film is dried to an almost dry state. In order to prevent foaming during drying, drying is performed at a temperature of 100 ° C. or lower, and when the drying is performed to a certain degree, 1
It is preferable to perform the drying completely at a temperature of 00 ° C or higher. After drying, 200-250 ° C, preferably 220-240 ° C
Stretching is performed at the temperature. About 20 in the hot air drawing furnace
It takes 2 seconds to 3 minutes. The draw ratio is preferably 5 times or more, more preferably 6 times or more. The drawn fiber is subjected to a heat treatment for achieving a fixed length or shrinkage, if necessary. The fiber thus obtained is further crimped or oiled if necessary.

The method for producing activated carbon fiber of the present invention is such that when the activated carbon fiber is produced by using the PVA type fiber obtained by the above-mentioned formulation as a starting material, the activated carbon is converted from the spinning stock solution of the PVA type resin. The fiber is characterized in that it is produced at a draw ratio of 2 to 6, and preferably, the irregularities on the surface of the activated carbon fiber can be controlled by such a production method.

When producing activated carbon fibers from PVA-based fibers, since PVA fibers have a melting point in the vicinity of 200 ° C. to 250 ° C., some infusibilizing treatment is indispensable, and PVA fibers cannot be treated by heat treatment in an oxidizing atmosphere. It is disclosed in Japanese Examined Patent Publication No. 38-20353 that the fusion treatment is performed.
Further, a method of producing a carbonaceous substance by mainly using an acid (hydrochloric acid, sulfuric acid-based, phosphoric acid-based) as a dehydration accelerator and performing heat treatment in an oxidizing atmosphere is also known (Japanese Patent Publication No. S45-45).
-31707 gazette, Japanese Patent Publication No. 48-1423 and 48-
39724, ibid 49-13430, ibid 49-2489.
7, 50-35431, 50-52320, 50
-52321, 51-38525, 53-1149.
25, 59-187624).

However, in the above patent publication, PVA is used.
No attention has been paid to the irregularities of the activated carbon fibers, and the stretching ratio of the activated carbon fibers is not described in the examples. The present inventors have for the first time found that controlling the total draw ratio is very important for the unevenness of the surface.

The stretching ratio of the PVA fiber as the starting material is not particularly limited, but if the stretching ratio is too small, the process passability is poor and fluffing is likely to occur, and if the stretching ratio is too large, then Since the shrinkage during heat treatment is severe and the process passability may be deteriorated, the draw ratio is preferably 3 to 10 times,
It is more preferable to set it to 2 to 6 times.

In order to effectively reduce the weight loss, PVA
It is very effective to add, mix, and apply a dehydration catalyst to the base fiber. The dehydration catalyst is not particularly limited, but various acidic compounds are preferably used, for example. The acidic compound can be appropriately selected from known compounds, and specific examples of such a compound include sulfuric acid, hydrogen sulfate,
Examples thereof include inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid, hydrogen phosphate and metaphosphoric acid, and further Lewis acids such as zinc chloride, aluminum chloride, iron chloride and titanium chloride.

When the treatment liquid is acidic and there is a problem in terms of safety and mechanical materials, ammonium salts neutralized with organic amines such as ammonia, specifically ammonium sulfate, phosphoric acid 2 By treatment with a treatment liquid such as ammonium or ammonium phosphate, ammonia is scattered during heating and an inorganic acid appears and acts. It is known that the dehydration catalyst accelerates the dehydration reaction of PVA and is therefore effective in shortening the heat treatment time, and also improves the yield because of efficient dehydration.

The amount of the dehydrating agent used is not particularly limited as long as it can accelerate the dehydration reaction, and the optimum amount varies depending on the kind of the dehydrating agent used, but cannot be specified unconditionally. 0.2 to 20% by weight is preferable. These dehydrating agents are used in the production of carbonaceous materials,
Since it decomposes and volatilizes in the exhaust gas to cause corrosion of the device, or remains as contamination and adversely affects the product, it is more preferable to reduce the amount used as much as possible, 0.2 wt% to 5 wt% % Is more preferable.

The infusibilizing treatment is not particularly limited, but the PVA fiber or the PVA fiber added with a dehydration catalyst may be heat-treated in an oxidizing atmosphere while applying tension. Although heat treatment without tension is possible, it is difficult to control the draw ratio of the activated carbon fiber, and a method of controlling shrinkage under tension is more preferable.

The tension applied to the fibers during the heat treatment is not particularly limited because it is greatly affected by the heat treatment conditions, the draw ratio of the raw material, etc. However, if the tension is too low, shrinkage unevenness may occur when the reaction is carried out rapidly. And as a result,
It may be difficult to control the draw ratio, and if the tension is too high, fluffing is likely to occur and the fiber may be cut, so the tension is 0.01 g / dtex to 0.5 g.
It is preferably carried out in the range of / dtex.

It is not clear why the tension control in the above range is effective in controlling the draw ratio, but when the reaction is rapidly advanced, the contraction force due to the relaxation of contraction becomes very large and the tension is applied to suppress the contraction. Although the need arises, the strength of the fiber decreases as the dehydration reaction proceeds, and the fiber is cut if more tension is applied than necessary, so it is presumed that it is necessary to balance the tension within a certain range. Also,
Since the strength of the yarn decreases as the weight decreases, it is preferable to reduce the tension stepwise. The weight decrease is 60%.
In the case of progressing above, it may be better to carry out at 0.01 g / dtex or less or without tension.

The temperature of the heat treatment is appropriately selected depending on the form of the raw material fibers and whether or not the dehydration catalyst is added, but it is preferably 150 ° C. or higher and 500 ° C. or lower. However, it may melt even if it is suddenly used at a temperature higher than the melting point. Therefore, in the case of processing at a high temperature, a method of raising the temperature by applying a thermal gradient is also effective, and it may be carried out in one step or divided into two or more steps.

The heat treatment time is appropriately determined depending on the form of the raw material fibers, the presence or absence of addition of a dehydration catalyst, the intended use of the carbonaceous fibers or fibrous activated carbon to be finally obtained, but if the treatment time is too short, the weight loss will be sufficient. However, if it is too long, the productivity only decreases, and it is usually preferable to carry out the treatment in 30 minutes to 5 hours. The infusibilizing atmosphere is not particularly limited, but an atmosphere containing oxygen is preferable, and the oxygen concentration is 0.5 by volume.
% To 21% is preferable.

The weight yield after the infusibilization treatment is not particularly limited, but it is carried out so that the weight yield of the fibers after the infusibilization treatment is 45 to 85% by weight, preferably 50 to 75% by weight. Is preferred. If the weight yield is too low, the weight yield of the fibrous activated carbon obtained will decrease, which is not preferable. On the other hand, if the weight yield is too high, the infusibilizing effect, which is the original purpose, may not be exhibited, and melting may occur, which is not preferable.

The infusibilized fiber thus obtained is used as such for various electrode materials, conductive materials, heat insulating materials,
It is preferably used as an adsorbent material, a flameproof material, an antistatic material, a heat resistant material, a chemical resistant material, and the like, and can be activated carbon fiber by further activating the carbonaceous fiber. Hereinafter, the activation treatment step will be described in detail. In addition, after cooling once from the infusibilizing process described above, the process may be moved to the activation process or continuously.

The activation method is not particularly limited as long as it can efficiently increase the specific surface area, and generally, it is prescribed in an atmosphere of carbon dioxide gas, steam, air, nitrogen or a mixed gas thereof. Carried out at a temperature of. The temperature and time of the activation treatment may be appropriately determined depending on the desired specific surface area, atmosphere and the like. For example, in the case of water vapor or carbon dioxide gas atmosphere, it is usually 500 to 1200 ° C., preferably 70.
The activation treatment may be performed at 0 ° C to 1000 ° C for several minutes to several hours,
800 to 12 when using combustion gas of propane gas
It can also be rapidly activated at a high temperature of 00 ° C.

Although the shrinkage of the fiber is observed in the activation step, if tension is applied more than necessary in the activation step, yarn breakage and fluffing frequently occur. Therefore, it is preferable to shrink the fiber freely without applying tension. PV obtained as described above
The higher the draw ratio of the A-based activated carbon fiber, the less the surface irregularities tend to be, and the draw ratio is preferably 2 to 6 times, more preferably 2 to 4 times. The reason why the draw ratio of the PVA-based activated carbon fiber is effective in forming unevenness on the surface is not clear, but it is speculated that surface unevenness may be formed when the fiber shrinks.

By using PVA-based resin as a raw material and controlling the activation conditions, the volume of the pores whose pore radius measured by the water vapor adsorption method is in the range of 20 to 50Å becomes 1
It is possible to obtain an activated carbon fiber having a volume of 10% or more of pores of 100 Å or less. That is, in order to produce such activated carbon fiber, the activation temperature, time and atmosphere are important, and the temperature is 800 ° C to 1000 ° C and the time is 1
It is preferable to carry out the atmosphere for 0 minutes to 6 hours with the volume ratio of water vapor in the total gas being 10% to 100%. Above all, it is more preferable that the temperature is low, the time is long, and the amount of water vapor is large.

The activated carbon fiber thus obtained is
It is preferably molded into a cartridge and used in a water purifier. Molding into a cartridge may be carried out by a known method. For example, activated carbon fibers and a binder are well mixed, and the mixture is dispersed in water so that the solid content concentration is preferably 1 to 5% by weight to form a slurry. Is prepared, and the slurry is poured into a water-permeable container having a desired shape prepared in advance and dried to obtain a molded body.

As the binder, microfibrillated fibers such as microfibrillated polyethylene, polypropylene, cellulose, acryl and aramid, heat fusible fibers such as polyethylene fibers, polypropylene fibers and polyester fibers, polyethylene powder, polypropylene powder, etc. The heat-fusible resin powder, the thermosetting resin powder, or the like can be used.

As the shape of the container, various water-permeable materials can be used, and the slurry can be poured into this container to form various molded bodies. For example, a water-permeable cylindrical container is made of stainless steel wire mesh, and a small-diameter cylindrical container is made by inserting wire mesh of the same length into this to form a double-tube container. The molded body can be obtained by pouring the slurry between the inner tube and the outer tube of the container. The molded body is dried, cut into an appropriate length, filled in a housing as a cartridge, and used as a water purifier. The water purifier may be used in a known form, for example, a water purifier using only the cartridge of the present invention, or a water purifier in combination with a hollow fiber membrane.

As a method for passing the raw water through the water purifier, a full filtration method for filtering the whole raw water or a circulation filtration method is usually adopted. The conditions for passing water are not particularly limited, but it is preferably carried out at a space velocity of 1000 to 2000 Hr ⁻¹ . The performance of the water purifier is the removal rate calculated from the concentration of free chlorine in the raw water and the permeated water, and the ratio of the amount of water (L) that has flowed since the start of water flow to the volume (cc) of the cartridge (cumulative permeated water amount L It can be confirmed by plotting the relationship with / cc). According to the water purifier of the present invention, it is excellent in removing free chlorine, trihalomethane, musty odor, environmental hormones, etc., and is also effective for decolorization. Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples. The method of measuring various parameters that define the activated carbon fiber of the present invention is as follows.

<Average Roughness of Activated Carbon Fiber Surface> Atomic force microscope device (DI-31 manufactured by Digital Instruments)
00) was used to measure the shape of the surface in the tapping mode. Prior to sample measurement, a reference sample with a pitch of 10 μm and a step of 180 nm was measured, and the measurement error of the device was ± 5.
It was confirmed to be within%.

The observation area of the sample was 5 μm square and the measurement frequency was 0.5 Hz. The obtained measurement data was analyzed by the data processing software attached to the device to obtain the average roughness. That is, the measurement software of the device is switched to the off-line mode (Off-line Mode) to modify / flatten (Modify / Flatte).
n) After smoothing a large swell of data by an instruction, analysis / section (Analysis / Se)
(section) command, a cross-sectional shape was obtained from the measurement data, and Ra at a plane-direction length of 5 μm calculated at that time was taken as the average roughness. When the x axis is the horizontal direction, Ra is given by the following definition. Where f (x)
Is the height from the center line, and Lx is the horizontal distance.

[0062]

[Equation 1]

<Weight reduction after heat treatment at 250 ° C.> The value of weight reduction after heating from 50 ° C. to 250 ° C. at 10 ° C./min in a nitrogen atmosphere and holding for 1 hour was used.

<Measurement of Pore Size Distribution by Steam Method> The steam pressure on a sulfuric acid aqueous solution having a constant concentration has a constant value. From this fact, there is a uniform relationship between the sulfuric acid concentration and the water vapor pressure, and activated carbon fibers are put into the adsorption chamber where the sulfuric acid concentration is changed at several points, the saturated adsorption amount is measured, and the water vapor pressure obtained from the sulfuric acid concentration ( P)
The pore radius was calculated from P / P0, which was calculated from the water vapor pressure (P0) of water at 30 ° C. Further, the cumulative pore volume from the amount of water vapor to the pore diameter was obtained, and this was plotted to obtain the pore diameter distribution of the water vapor adsorption method. The following Kelvin equation was used for the relationship between the water vapor pressure and the pore radius.

[0065]

[Equation 2] r: Pore radius (cm) Vm: Water molecular volume (cm3 / mol) = 18.079 (30 ° C) τ: Surface tension (dyne / cm) = 71.15 (30 ° C) θ: Capillary wall and water The contact angle with (°) = 55 ° was used. R: Gas constant (erg / deg · mol) = 8.3143 × 10 7 T: Absolute temperature (K) P: Saturated water vapor pressure of water in pores (mmHg) P0: Saturated water vapor pressure of water at 30 ° C. (mmHg) ) = 31.824

[0066]

Example 1 PVA having a degree of polymerization of 1700 and a degree of saponification of 99.8% was put into water and dissolved by stirring under a nitrogen stream at 80 ° C. to prepare a spinning dope having a PVA concentration of 16% by weight. The spinning solution was added with a pore size of 0.1
30% by weight through a spinning nozzle with 2 mm and 1000 holes
Was spun into a solidification bath at 30 ° C. consisting of an aqueous solution of sodium sulfate, and wet-spun. The PVA fiber obtained was immersed in the same solidifying bath for 1 minute and stretched 2.5 times to obtain 35 wt% at 20 ° C.
It was immersed in an aqueous solution of sodium sulfate for 1 minute, stretched in a saturated aqueous solution of sodium sulfate at 90 ° C. so that the total stretching ratio was 4.5 times, and immersed in the same bath for a fixed length of 30 seconds.

Next, after washing with water at 10 ° C. for 2 minutes under running water to remove sodium sulfate, it was dried with hot air at 130 ° C. and wound up. The dried PVA fiber is then applied to 17
Hot drawing was performed in a hot-air oven consisting of a first furnace at 0 ° C and a second furnace at 235 ° C so that the total draw ratio was 10 times. The fibers were squeezed with a diple mangle for 5 seconds in an aqueous solution of ammonium sulfate at 25 ° C. and 2% by weight (a ratio of sulfuric acid to the total amount of ammonium sulfate and water), and dried at 105 ° C. for 3 minutes. The content of ammonium sulfate in the fiber was 0.6% by weight.

The fibers were mixed in an oxygen-containing nitrogen gas containing 5% by volume of oxygen at a gas flow rate of 40 Nm ³ / kg and 0.04 g / dtex.
While applying the tension of 4 minutes, total heat treatment time 4 minutes, 220
Dehydration treatment was performed at ° C. The dehydrated fiber obtained was blackish brown, and the weight yield based on PVA was 76% by weight. Then, the dehydrated fiber thus obtained was mixed with oxygen at a volume ratio of 5
% Oxygen-containing mixed gas, gas flow rate is 40 Nm ³ / kg
At a tension of 290 ° C. of 0.01 g / dtex for 50 minutes for infusibilization. The obtained black infusible treated fiber was very flexible, the weight yield was 57% by weight based on the raw material, and the total draw ratio from the raw material was 5 times.

Next, the black carbonaceous fibers were activated for 180 minutes at 880 ° C. in a combustion gas of propane (H ₂ O and CO ₂ were the main components and contained 16% by volume of steam). After activation, the fibers were washed with running water and dried to give fibrous activated carbon. The weight yield with respect to the raw material fiber was 11% by weight, and the total draw ratio from the raw material was 4 times. B measured by nitrogen adsorption
The ET specific surface area was 2080 m ² / g. The average roughness of the surface is 18 nm, the weight loss after heat treatment at 250 ° C. is 0.01% by weight, and the pore radius measured by the steam adsorption method is 2
Pore radius 100 for pore volume in the range of 0 to 50Å
The ratio (V ^{20 to 50} ) to the volume occupied by the pores of Å or less was 28%.

Example 2, Comparative Example 1 The procedure of Example 1 was repeated except that the total draw ratio of PVA fiber was changed as shown in Table 1. The results are shown in Table 1. In Comparative Example 1, the stretching ratio was too high to pass the process.

[0071]

[Table 1]

Comparative Example 2 According to Example 1 described in JP-A-7-145516, the polymerization degree (Example 1) was produced by heat-treating petroleum cracked residual oil. Specific gravity 1.24, softening point 261 ° C., An optically isotropic pitch having an aromatic hydrocarbon fraction fa of 0.54 was melt-spun into fibers. The temperature of this fiber is 170
Introduced into the air heating furnace of ℃, 3 ℃ / due to the temperature gradient in the furnace
The temperature was raised to 300 ° C. in minutes to infusibilize. The oxygen content of the infusibilized fiber was 6.5%. The fibers were carbonized by further raising the temperature to 500 ° C. at a heating rate of 20 ° C./min in a nitrogen stream. The obtained carbon fiber was activated in the same combustion gas of propane as in Example 1 at 950 ° C. for 12 minutes, and subsequently post-treated at 900 ° C. for 15 minutes in nitrogen to obtain activated carbon fiber.

The activated carbon fiber thus obtained had a BET specific surface area of 1300 m ² / g as measured by the amount of adsorbed nitrogen, an average surface roughness of 3 nm and a weight loss of 0.0 after heat treatment at 250 ° C.
2% by weight and V ^{20 to 50} were 1.0%.

Comparative Example 3 A fiber obtained by melt-spinning a pitch in accordance with Example 1 described in JP-A-62-152534 is air-processed in air.
(200 ° C x 1 hour) + (240 ° C x 1 hour) + (27
(0 ° C. × 1 hour), heat treatment was performed in three stages at different temperatures to obtain fibers having an oxygen content of 7.4%. Next, the fiber was heat-treated at 1000 ° C. for 15 minutes in a nitrogen stream. The obtained carbonized fiber had a carbon content of 91.5% and a specific surface area of 0.1 m ² / g. Next, the carbonized fiber was activated by being treated in a steam flow at a temperature of 900 ° C. for 20 minutes.

The BET specific surface area measured by the nitrogen adsorption amount of the obtained activated carbon fiber was 2000 m ² / g, the average roughness of the surface was 2.5 nm, and the weight loss after heat treatment at 250 ° C. was 0.02% by weight. , V ^20-50 was 1.5%.

Comparative Example 4 Phenolic fiber (Novoloid fiber manufactured by Nippon Kynol Co., Ltd.) was used in the same combustion gas of propane as in Example 1 at 880 ° C.
It was activated for 180 minutes. After activation, the fibers were washed with running water and dried to give fibrous activated carbon. The weight yield based on the raw material fibers was 20% by weight. The BET specific surface area measured by the amount of adsorbed nitrogen was 2010 m ² / g. The average roughness of the surface was 3 nm, the weight loss after heat treatment at 250 ° C. was 0.02% by weight, and V ^{20 to 50} was 0.5%.

Comparative Example 5 According to Example 1 described in JP-A-50-148627, polynosic fibers (5d, 5 cm) were impregnated with a 10% aqueous solution of phosphoric acid and then dried to obtain phosphorus as a dry weight of the fibers. 1.5 wt% phosphoric acid was deposited. The obtained pretreated fiber was mixed with propane combustion gas (N ₂ 80%, CO 5
%, CO ₂ 10%, O ₂ 2%, steam and others 3%)
The temperature was raised to 270 ° C. in about 5 minutes and kept at this temperature for 30 minutes. After this low temperature heat treatment process, 30% by volume of steam is added.
850 in the mixed gas of the combustion gas and steam contained
Activation was carried out by heat treatment at 30 ° C. for 30 minutes to obtain activated carbon fibers.

The activated carbon fiber thus obtained had a BET specific surface area measured by nitrogen adsorption of 1350 m ² / g, an average surface roughness of 4.2 nm, and a weight loss after heat treatment at 250 ° C. of 0.04% by weight. , V ^20-50 was 6%.

Example 3 100 mg of the activated carbon fiber obtained in Example 1 was mixed with vitamin B ₁₂ (C ₆₃ H _{8 8} N ₁₄ O ₁₄ PCo: molecular weight 1).
355.4) was added to water containing 3 ppm, and the mixture was permeated at 25 ° C. for 1 minute for 24 hours. Then, the residual amount of vitamin B ₁₂ from the filtrate obtained by filtering the activated carbon fiber was calculated by measuring the absorbance at 330 nm, and the adsorption amount of vitamin B ₁₂ per g of activated carbon fiber was calculated.
30 mg / g, 166 mg / g for 24 hours
Met.

Example 4, Comparative Examples 6 to 9 The procedure of Example 3 was repeated except that the activated carbon fiber was changed. The results are shown in Table 2. From these results, Examples 1 and 2
Activated carbon fiber has a high adsorption rate and also contains vitamin B.
It is clear that it is excellent in adsorbing macromolecules such as ₁₂ .

[0081]

[Table 2]

Example 5 100 parts by weight of fibrous activated carbon having a BET specific surface area of 1632 m2 / g measured by nitrogen adsorption amount produced by activating for 90 minutes in the same manner as in Example 1 was pulverized with a mixer in water,
5 parts by weight of acrylic binder fiber (R56F manufactured by Toyobo Co., Ltd.) and water are added to the mixture to form fibrous activated carbon: binder: water = 2:
A 0.10: 97.90 (wt%) molding slurry was prepared. 200 mesh stainless steel wire mesh with a diameter of 3.
A cylindrical container having a length of 6 cm and a length of 6 cm was prepared, and a cylindrical container having a diameter of 1 cm and a length of 8 cm made of the same wire mesh was inserted thereinto to prepare a double-tubular container. The above-mentioned slurry was poured between the inner tube and the outer tube of the double tubular container and dried to prepare a cylindrical molded body. The molded body is 7 cm long
Cut into pieces, outer diameter 3.6 cm, inner diameter 1 cm, length 7 cm
A cartridge having a volume of 65 cc and a weight of 11 g was loaded in the housing to form a water purifier.

The evaluation of the obtained water purifier was conducted according to JIS S32.
It carried out according to 01. That is, tap water contains sodium hypochlorite and 2-methylisoborneol (2-MI).
B) is added, water temperature is 20 ± 1 ℃, free chlorine concentration is 2pp
m, 2-MIB concentration of raw water adjusted to be 50 ppt from the outside of the cartridge 1.1 liter (L) /
The test was conducted by passing water through the all-filtering system at a rate of minute (SV = 1000 Hr ⁻¹ ). For filtered water, free chlorine D
Measured by spectrophotometer by PD method and measured 2-MIB concentration by G
It was measured by the C-MS method. The ratio of the amount of water (L) flown from the start of the test to the volume (cc) of the cartridge was defined as the cumulative amount of permeated water (L / cc), and the removal rate of free chlorine (%) and 2-
The relationship with the removal rate (%) of MIB was investigated. The results are shown in Table 3 and FIG. The chlorine removal performance and the 2-MIB removal performance are represented by the cumulative amount of permeated water when the removal rate reaches 80%.

Comparative Examples 10 and 11 BET specific surface areas 11507 m 2 / g and 2036 m measured by the amount of adsorbed nitrogen prepared from phenol resin as a raw material.
A cartridge was prepared in the same manner as in Example 5 except that 2 / g of two types of fibrous activated carbon (FR-15 and FR-20, manufactured by Kuraray Chemical Co., Ltd.) were used. The removal rate of 2-MIB was investigated. The results are shown in Table 3 and FIG.

[0085]

[Table 3]

[0086]

According to the present invention, the average roughness of the surface is 5 nm.
The above activated carbon fibers can be provided. The activated carbon fiber of the present invention is preferably produced by a method of producing an activated carbon fiber using PVA-based fiber as a raw material and converting the spinning raw yarn of the PVA-based resin to a draw ratio of the activated carbon fiber of 3 to 10 times. can do. Since such activated carbon fibers are excellent in adsorption of macromolecules, such as water purification applications, air cleaning applications, solvent recovery applications, gas adsorption applications, water treatment applications, decolorization applications, tobacco filter applications, clean room filter applications, blood purification applications, etc. In addition to various applications, it is useful as an electrode material for secondary batteries, an electrode material for electrolytic capacitors, an electrode material for electric double layer capacitors, etc., and in particular, such activated carbon fiber is molded into a water purifier cartridge, It is suitable as a water purifier using.

[Brief description of drawings]

FIG. 1 is a graph showing water purification performance of a water purifier according to a fifth embodiment.

FIG. 2 is a graph showing water purification performance of water purifiers in Comparative Examples 10 and 11.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 1/28 C02F 1/28 G D01F 9/14 513 D01F 9/14 513 (72) Inventor Toshiaki Itaya Okayama Kuraray Co., Ltd., 2045 Sakuzu, Kurashiki, Japan (72) Inventor Yoshiharu Fukunishi 3-38 Doyama-cho, Kita-ku, Osaka Kuraray Chemical Co., Ltd. (72) Inventor Moto Aoki 4342 Tsurumi, Bizen, Okayama Kuraray Chemical Co., Ltd. In-house F-term (reference) 4D024 AA02 AB11 BB02 BB05 BC01 CA04 CA11 4G066 AA05B AA47D AA51D AC12A BA03 BA07 BA16 BA23 BA24 BA25 BA26 BA50 CA02 CA10 CA31 CA51 CA52 CA54 DA01 DA03 DA07 DA08 DA12 FA11 FA14 FA18 FA21A06 A FA AD33 BA13 BA42 BD02 BD03 BD04 4L037 AT11 CS06 FA01 FA20 PA46 PC06 PC08 PS03 PS12 PS17 UA20

Claims (9)

[Claims] 1. An activated carbon fiber having an average surface roughness of 5 nm or more. 2. The activated carbon fiber according to claim 1, which has a cross-sectional solidity of 40 to 100%. 3. The weight loss after heat treatment at 250 ° C. is 0.
The activated carbon fiber according to claim 1 or 2, wherein the content is 03% by weight or less. 4. The volume distribution of pores whose pore distribution is in the range of 20 to 50 Å, measured by the water vapor adsorption method, is 10% or more of the volume occupied by pores having a radius of 100 Å or less. Item 4. The activated carbon fiber according to any one of items 1 to 3. 5. The activated carbon fiber according to claim 1, wherein the activated carbon fiber is an activated carbon fiber made of a polyvinyl alcohol fiber as a raw material. 6. A method for producing activated carbon fiber, which comprises using polyvinyl alcohol fiber as a raw material and converting the spinning raw yarn of polyvinyl alcohol resin into a stretch ratio of 3 to 10 times the activated carbon fiber. 7. The method for producing activated carbon fiber according to claim 6, wherein the raw material is polyvinyl alcohol fiber to which a dehydrating agent is attached. 8. A water purifier cartridge obtained by molding the activated carbon fiber according to claim 1. 9. A water purifier using the cartridge.