JP2003292317A - Processes for producing carbonaceous substance, carbonaceous substance obtained by the process and active carbon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide processes of producing a carbonaceous substance which are useful in industries and by which the corrosion of an apparatus can be prevented; the contamination and heat accumulation of the final product can be suppressed; and a great amount of the substance can be produced in a short period, and also to provide the carbonaceous substance obtained by the above processes and an active carbon obtained by activating the above substance. <P>SOLUTION: The activated carbon is obtained by activating the carbonaceous substance prepared by either one of following processes: heat treating a polyvinyl alcohol based resin which has more than 0.2 wt.% to 1 wt.% of a dehydrating agent adhered there to, or its molding as a source material; heat treating a polyvinyl alcohol based resin in an atmosphere containing oxygen by a batch process at a gas flowing rate not less than 1 Nm<SP>3</SP>/hr.kg or by a continuous process at a gas flowing rate not less than 1 Nm<SP>3</SP>/kg; heat treating a polyvinyl alcohol based resin or its molding in a gas containing not less than 0.5 volume % to 15 volume % of oxygen. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a carbonaceous substance, a carbonaceous substance, and activated carbon. More specifically, a method for producing a carbonaceous substance using a polyvinyl alcohol-based resin or a molded product thereof (hereinafter, polyvinyl alcohol is abbreviated as PVA) as a raw material, a carbonaceous substance obtained by the producing method, and the carbonaceous substance It relates to activated carbon obtained by activating. The carbonaceous substance and activated carbon of the present invention are suitably used for various electrode materials, heat insulating materials, adsorbent materials, flameproof materials and the like.

The carbonaceous material can be applied to carbon fibers and activated carbon fibers by further forming it into a fiber form. Carbon fiber is suitable for the above-mentioned heat insulating material, flameproof material, etc.,
Activated carbon fibers are suitable for applications such as water purification, air purification, gas adsorption, water treatment, solvent recovery, decolorization, tobacco filters, clean room filters, and blood purification. It is also useful as an electrode material for secondary batteries, electrolytic capacitors, electric double layer capacitors and the like.

[0003]

2. Description of the Related Art Up to now, many reports have been made on carbonaceous substances using PVA-based resins or molded products thereof as raw materials. For example, Japanese Patent Publication No. 38-20353 discloses PV.
A method for producing a carbonaceous material by heating a molded body such as an A-based resin or fiber at a temperature of 400 ° C. or lower in an oxidizing atmosphere is disclosed. And regarding the heating step, since the thermal decomposition temperature is around 200 ° C to 240 ° C,
It is described that the heat treatment is preferably performed in an oxidizing atmosphere at a temperature lower than the thermal decomposition temperature, and in specific examples, an example of heat treatment at 200 ° C. or 180 ° C. is shown.

However, such a heat treatment requires 1
This is a process that requires a very long time of 5 hours or more and has low productivity, so it cannot be said to be an industrially advantageous method. On the other hand, when proceeding the dehydrogenation reaction, 250
It is also described that heat treatment at a temperature of from ℃ to 400 ℃ is effective. However, when the present inventors conducted a detailed study on this point, when the PVA-based resin or its molded product was suddenly introduced into this temperature range under an oxidizing atmosphere, the decomposition reaction due to heat storage was accelerated and burned. It turned out to be a problem.

Japanese Patent Publication No. 40-9061 discloses a method for producing a fibrous carbon material by reacting a polymer fiber containing vinyl alcohol or a derivative thereof with halogen or a compound thereof and then firing the polymer fiber. There is. It is described that this production method has an effect of improving yield and improving mechanical properties. However, as is clear from the examples, in such a method, a large amount of halogen is used, and in addition to the necessity of supporting the apparatus by using halogen, there is a concern that the apparatus may be corroded by hydrogen halide during heat treatment, It is not a recommended method from the viewpoint of industrialization.

In Japanese Patent Publication No. 45-31707, vinyl alcohol fiber is heated at a temperature between 100 ° C. and 300 ° C. in an atmosphere containing hydrochloric acid gas and vapor of a non-oxidizing acid, and then air. 1 in other oxidizing atmospheres
Heating at a temperature between 50 ° C and 300 ° C, and then
A carbonized fiber obtained by heating at a temperature between 300 ° C. and 1000 ° C. in a non-oxidizing atmosphere and a method for producing the same are disclosed. And according to this method, shrinkage suppression
It is described that it is effective in improving the yield. However, from the viewpoint of industrialization, there is a concern that the equipment may be corroded during the heat treatment in a hydrochloric acid gas atmosphere, and regarding the subsequent heat treatment in an oxidizing atmosphere, as is clear from the examples, the temperature of 3 ° C. at 200 ° C. It takes a long time of 16 hours at 230 ° C. or 230 ° C., and it is hard to say that it is excellent in productivity.

Japanese Unexamined Patent Publication (Kokai) No. 48-1423 discloses that a synthetic fiber composed of 10 to 35% by weight of polyvinyl chloride and 90 to 65% by weight of PVA is preoxidized in air at 150 to 235 ° C. for 5 to 10 hours. And then 250-3 in nitrogen
A method for producing carbon fibers is disclosed, which is pre-fired at 50 ° C. for 2 to 5 hours and further carbonized to 1200 ° C. in 5 to 7 hours. It is described that this manufacturing method is effective in suppressing shrinkage and shortening production time. However, there is concern that the hydrochloric acid gas generated from polyvinyl chloride during heat treatment may corrode the device. In terms of productivity, the total heat treatment time is as long as 10 hours or more as far as the Examples are concerned, and it cannot be said that this is a rational production method.

JP-A-48-39724 discloses a PVA-based carbon fiber for carbonizing a fiber obtained by wet spinning a PVA aqueous solution having an average degree of polymerization of 2000 or more in a coagulation bath of an aqueous solution mainly containing caustic alkali. A manufacturing method is disclosed. According to this manufacturing method, it is described that the strength and flexibility are effective, but there is little description about the heat treatment conditions, and in Examples, the temperature is set to 210 ° C. or less in air for a long time (5
Only ~ 15 hours) is mentioned. Therefore, the productivity is low, the resin, the spinning method, etc. are limited, and since it is coagulated with an aqueous solution mainly containing caustic, it is very dangerous, and it is recommended from the industrial viewpoint. I can't say.

JP-A-48-41041 discloses that a vinylidene chloride component obtained by mixing and spinning an aqueous emulsion of vinylidene chloride homopolymer or vinylidene chloride copolymer and PVA is 30% by weight or more and the PVA component is A method for producing a PVA-based carbon fiber in which 30% by weight or more of carbon is carbonized is disclosed. According to this manufacturing method, it is described that the process and time are shortened, and the yield is improved. However, during the heat treatment, corrosion of the device by hydrochloric acid gas which is a decomposition gas generated from polyvinylidene chloride is caused. I'm worried. Further, the spinning method and the like are also limited, and it cannot be said that the method is industrially advantageous.

JP-A-48-41042 discloses a PV.
A method for producing a PVA-based carbon fiber is disclosed in which a carbon-carbon double bond is introduced into an A-based fiber, chlorine or / and bromine is added thereto in an amount of 10% by weight or more, and then carbonized. According to this method, it is described that the process and time are shortened, and the yield is improved. However, a halogenation process is required, and it is necessary to cope with the apparatus.
Furthermore, there is concern that the equipment may be corroded by hydrogen halide during the heat treatment, which increases the manufacturing cost due to the equipment compatibility. Therefore, this method is considerably disadvantageous from an industrial point of view.

JP-A-49-13430 discloses a PV.
In producing carbonaceous fiber by heating A-based synthetic fiber,
A method for producing carbonaceous fibers is disclosed in which PVA-based fibers are pretreated with a hydrophobic organic solvent having a dielectric constant of 10.0 or less. According to this production method, it is described that it is effective in improving the soft texture, but a pretreatment step with an organic solvent is required, and an apparatus therefor is also required. Regarding heat treatment conditions, as seen in the examples, heat treatment is performed for 5 hours or more, and it is hard to say that this is an advantageous method in view of productivity.

JP-A-49-24987 discloses that a PVA fiber containing at least one of sodium hydrogensulfate and potassium hydrogensulfate or a product thereof is heated in an oxidizing atmosphere at a temperature of 220 ° C. or lower, A method for producing a PVA-based carbon product which is then fired in a non-oxidizing atmosphere is disclosed. And according to this manufacturing method, yield improvement,
It is described that there are effects such as flexibility, high strength, and prevention of heat storage. However, according to the examples, it is considered that the infusibilization is performed at a temperature of 220 ° C. or lower, so that the reaction rate of infusibilization is slow and the heat treatment requires a long time, but the heat treatment requires a long time of 10 hours or more. However, it is not a realistic production method when productivity is taken into consideration.

In Japanese Patent Laid-Open Publication No. 50-35431, a heat-treated high-stretching and fine-fineness PVA-based synthetic fiber filament is used as a starting material, and a weight loss of 20 to 35% is achieved without strain in the presence of a dehydration catalyst. Carbon that is subjected to carbonization or graphitization treatment in an inert gas atmosphere containing no oxygen in a tension state after being subjected to a heat dehydration treatment for 1 to 5 hours in an oxidizing atmosphere at a temperature of 150 to 200 ° C. A method of making fibers is disclosed. According to this method, it is described that there is an effect on cost reduction by shortening the production time, but its application range is narrow because it is limited to heat-treated PVA with high stretching and fineness. As for the dehydrating agent, an example in which it is carried out only in a hydrochloric acid gas atmosphere is described in the examples, and there is a concern that the apparatus may be corroded. Further, the subsequent oxidation treatment also requires 1 to 5 hours, which is not an industrially advantageous method.

JP-A-50-52320 discloses a PV.
When producing carbon fibers using A-based synthetic fiber filaments as a starting material, PVA-based fiber filaments to which a dehydration catalyst of 3 to 20% by weight has been added are reduced in weight by 20 to 35% in an inert gas atmosphere without tension. Heat dehydration treatment is carried out so as to generate, and then 150 to 20 in an oxidizing atmosphere.
It discloses a method for producing carbon fibers, which is treated at a temperature of 0 ° C. for 1 to 5 hours and then heated and calcined in an inert gas under tension to be carbonized or graphitized. It is described that this method is a method for producing a carbon fiber which has low pollution and can be treated in a short time, is low in cost, and has high performance, but according to the examples, the weight is 20 to 35%. About 4 hours are required for the process of heat dehydration treatment so that the reduction occurs. Further, the oxidation treatment requires 1 to 5 hours, which is still insufficient from the viewpoint of shortening the time. Further, the subsequent heat treatment also requires a temperature rise, and there is a problem of melting when suddenly introduced into a high temperature of about 1000 ° C.

Japanese Patent Application Laid-Open No. 50-52321 discloses PV.
When producing carbon fiber using the A-based synthetic fiber filament as a starting material, the PVA-based synthetic fiber filament containing 3 to 20% by weight of a dehydration catalyst is reduced in weight by 20 to 35% in an oxidizing atmosphere without tension. The method for producing carbon fibers is disclosed in which carbon fibers are heated and calcined in an inert gas under tension and then carbonized or graphitized. This method has low pollution and can be processed in a short time,
It is described as a low-cost and high-performance method for producing carbon fiber. However, according to an embodiment, 20 to
4 in the process of heat dehydration so that weight loss of 35% occurs
It takes about 8 hours, which is still insufficient from the viewpoint of shortening the time. Further, the subsequent heat treatment also requires a temperature rise, and there is a problem of melting when suddenly introduced into a high temperature of about 1000 ° C.

JP-A-51-38525 discloses a PV.
There is disclosed a method for producing a carbon fiber in which PVA is maintained in a swollen state, radiation-treated, and then fired when A is fired to produce a carbon fiber. And, it is described that this method is effective in improving the yield by radiation treatment. However, according to this method, the heat treatment time requires a long time which is not much different from the conventional method.
Moreover, from the viewpoint of safety, radiation shielding equipment is essential.
It is hard to say that this is an industrially advantageous method.

JP-A-53-37594 discloses a PV.
Disclosed is a method for producing activated carbon in which concentrated sulfuric acid or fuming sulfuric acid is added to A and heat treatment is performed to activate the product. Then, this method is described as a method for producing activated carbon having an excellent adsorption amount. However, according to this method, since concentrated sulfuric acid is used, it is necessary to support equipment, and in the embodiment, as much as 500% by weight of concentrated sulfuric acid is used with respect to the raw material, which is a very realistic manufacturing method. It is hard to say.

JP-A-53-45685 discloses a PV.
A polymer compound selected from A and its copolymer is brought into contact with sulfuric acid, fuming sulfuric acid or sulfuric acid anhydride to obtain a sulfuric acid-treated product of these polymer compounds, and the treated product is then treated in an oxidizing gas or an inert gas. Discloses a method for producing activated carbon in which heat treatment is performed. And, this manufacturing method is described as a method for manufacturing activated carbon having an excellent adsorption amount. However, according to this method, a large amount of concentrated sulfuric acid, which is an extremely dangerous reagent, is used. Also, the index a is a specific surface area 400~900m ² / g of adsorption capacity of the resulting activated carbon, although not from those even large Compare with generally specific surface 1200~2000m ² / g of the active carbon employed However, it is hard to say that it is a high performance adsorbent.

Japanese Patent Application Laid-Open No. 53-114925 discloses that
(1) Dry spinning of a PVA spun raw yarn prepared by adding 3 to 15% by weight of an ammonium phosphate compound as a dehydration reaction accelerator to produce a raw material fiber, (2) a weight yield based on the raw material fiber The raw material fibers are heated and dehydrated at a temperature of 180 ° C. to 340 ° C. up to 65% to 85%, and (3) the dehydrated yarn is treated at 600 to 1000 ° C. in an atmosphere of an inert gas containing steam. There is disclosed a method for producing activated carbon fiber, which comprises activating treatment at a temperature until the weight yield of the raw material fiber becomes 10 to 35%. It is described that according to this production method, activated carbon fibers having an excellent adsorption amount can be obtained with low pollution and in a short time.

However, in this method, the dry spinning method is limited as the spinning formulation, and the ammonium phosphate compound is limited as the dehydration reaction accelerator, and the post-deposition of the dehydrating agent gives activated carbon fibers having excellent adsorption performance. It has been shown that this is not possible, and there is a major limitation in this respect. Further, when the present inventors examined this method in more detail, it melts when rapid activation is performed and heat is stored when a large amount is charged, so a large amount of charging cannot be performed, and therefore productivity is low and industrialization From a point of view, it turned out to be still insufficient.

[0021] In JP-A-59-187624, PVA-based fibers to which a dehydrating agent is attached or contained are heated until the weight loss becomes 35% or more, and dehydration and carbonization reaction are carried out to obtain carbonaceous fibers. 80 steps and the carbonaceous fiber obtained
Disclosed is a method for producing activated carbon fiber, which comprises a step of rapidly activating at high temperature at a temperature of 0 to 1200 ° C. and in the presence of a slight amount of oxygen. Then, this method is described as a method for producing activated carbon fibers having excellent adsorption performance. However, when the present inventors conducted a supplementary test, it was found that when a large amount was charged, heat could not be stored because a large amount of heat was stored, and therefore the productivity was low and it was still insufficient from the viewpoint of industrialization. did.

Japanese Patent Application Laid-Open No. 61-47827 discloses PV.
A hollow activated carbon fiber obtained by carbonizing an A-based fiber is disclosed. It is described that this fiber has a unique physical property that has both the adsorptivity peculiar to activated carbon and the permeability of the hollow fiber wall.
It is described that the point is to dry-distill from 0 ° C to 1000 ° C within 5 minutes. However, as for the infusibilizing condition before dry distillation, there is almost no description of specific conditions, and only a method of gradually heating to 180 ° C. to 300 ° C. until blackening is described. Therefore, when the present inventors conducted an additional test, it was found that when a large amount of material was charged, heat was accumulated and a large amount of material could not be charged, and this method also had low productivity.

The above-mentioned known techniques can be briefly summarized as described above. By mainly using an acid such as hydrochloric acid, sulfuric acid or phosphoric acid as a dehydration accelerator, the carbonaceous substance is removed by heat treatment in an oxidizing atmosphere. Manufacturing method (Japanese Patent Publication No.
No. 7, JP-A-48-1423, and JP-A-48-39.
No. 724, No. 49-13430, and No. 49-2.
No. 4897, No. 50-35431, No. 50-
No. 52320, No. 50-52321, No. 51
No. -38525, No. 53-114925, No. 59-187624), and a method for producing a carbonaceous substance by halogenating or sulfonation of a PVA resin without requiring heat treatment in an oxidizing atmosphere. (Japanese Patent Publication 4
0-9061, JP-A-48-41041,
No. 48-41042, No. 53-37594, and No. 53-45685).

The above method has been studied from various angles and improved, but
Problems such as storage of heat in a large amount to cause ignition, long time for dehydration and oxidation, and a large amount of dehydrating agent used, such as corrosion and contamination of the final product, have not yet been solved. Instead, it remains a major issue for industrialization.

On the other hand, in the method (1), it is necessary to deal with equipment such as halogenation and sulfonation, and an extremely dangerous step is required. Further, regarding halogenation, a large amount of hydrogen halide is generated during the heat treatment step. Therefore, it is indispensable to cope with equipment corrosion, and sulfonation is not preferable for the environment because a large amount of sulfurous acid gas is generated, and it is hard to say that all of them are realistic methods.

As described above, many reports have been made on carbonaceous substances, carbon fibers, activated carbon and activated carbon fibers made of PVA as a raw material, but they have not yet been industrialized. The main reason for this is considered to be that productivity is low and manufacturing cost is high because there are many steps and heat treatment requires a long time. As described above, although many reports have been made on carbonaceous substances using PVA-based resins or molded products thereof as raw materials, industrially advantageous methods for producing carbonaceous substances have not yet been established. The current situation.

[0027]

Therefore, the first object of the present invention is to provide a method for producing a carbonaceous substance which is capable of suppressing the corrosion of the apparatus and the contamination of the final product and which is industrially useful. is there. The second object of the present invention is to
An object of the present invention is to provide an industrially advantageous method for producing a carbonaceous substance, which can prevent heat accumulation and can be produced in a large amount in a short time. Further, a third object of the present invention is to provide a carbonaceous material obtained by such a production method, and a fourth object of the present invention is to provide activated carbon obtained by activating the carbonaceous material. To provide.

[0028]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that in order to produce a carbonaceous substance by suppressing the corrosion of the apparatus and the contamination of the final product. It is important to control the type and amount of dehydrating agent, and in order to prevent heat accumulation and produce a large amount of carbonaceous material in a short time, gas flow rate, oxygen concentration, heat treatment during heat treatment in an oxidizing atmosphere The inventors have found that it is important to control the temperature and the heat treatment time, and have reached the present invention.

That is, the first invention of the present invention is characterized in that a PVA-based resin or a molded product thereof to which a dehydrating agent is attached in an amount of 0.2% by weight or more and 1% by weight or less is used as a raw material, and this is heat treated. It is a manufacturing method of a quality substance.

A second aspect of the present invention uses a PVA-based resin or a molded product thereof as a raw material, the raw material is in an atmosphere containing oxygen, and the gas flow rate per raw material input is 1 Nm ³ / hr · kg.
Above batch method or gas flow rate per raw material input is 1
It is a method for producing a carbonaceous material, characterized in that heat treatment is carried out by a continuous method of Nm ³ / kg or more.

A third invention of the present invention uses a PVA-based resin or a molded product thereof as a raw material, and the raw material is 0.5% by volume or more and 15% by volume or more.
A method for producing a carbonaceous material, characterized in that the heat treatment is performed in an oxygen-containing gas of not more than volume%.

A fourth invention of the present invention is a carbonaceous substance obtained by any one of the above-mentioned production methods. And the 5th invention of this invention is the activated carbon obtained by activating these carbonaceous substances.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a PVA-based resin or a molded product thereof is used as a raw material for producing a carbonaceous substance. The PVA-based resin used in the present invention is obtained by saponifying polyvinyl acetate 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 highly polar vinyl ester, or a homopolymer or copolymer of vinyl ether such as t-butyl vinyl ether, trimethylsilyl vinyl ether or benzyl vinyl ether. It can be anything.

Here, the comonomer unit of the copolymer can be divided into a unit which produces a vinyl alcohol unit by saponification or decomposition and a unit other than the unit. The latter comonomer unit is mainly used 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.
The mol% is preferable. Here, the degree of saponification is the ratio of vinyl alcohol units after saponification to units that can be converted into vinyl alcohol units by saponification in a vinyl acetate homopolymer or copolymer, and the residue is acetic acid. It is a vinyl unit. The degree of polymerization of the PVA-based resin is preferably 1000 or more, more preferably 1700 or more. However, PVA with a degree of polymerization exceeding 30,000
Resins are generally difficult to manufacture, and are not necessarily suitable from the viewpoint of industrial production.

First, the first invention of the present invention is characterized in that a PVA-based resin or a molded product thereof having a dehydrating agent adhered thereto in an amount of 0.2% by weight or more and 1% by weight or less is used as a raw material and heat-treated. The method for producing the carbonaceous material will be described.

It is already known to use dehydrating agents,
The amount of the dehydrating agent used is about 3% to 20% in JP-A-50-52320, 50-52321, 53-114925, and the like, and JP-A-59-187624.
JP-A-49-13430 describes that the use amount is preferably 2 to 20%, and JP-A-49-13430 discloses that the use amount is preferably 1 to 20%. As previously reported, these dehydrating agents decompose during the production of carbonaceous materials and volatilize in the exhaust gas, causing the equipment to corrode or remaining as contaminants, which may adversely affect the product. However, these publications have not sufficiently examined them from the viewpoint of reducing the amount of dehydrating agent used.

The inventors of the present invention have made extensive studies as to the reduction of the amount of the dehydrating agent, and have found that the impregnation conditions and the selection of the dehydrating catalyst, which have not been paid attention to by the known techniques, are very important. That is, 0.2% by weight of dehydrating agent
It has been newly found that when a carbonaceous substance is produced by using the PVA-based resin or its molded product adhered in an amount of 1% by weight or less as a raw material, corrosion of the device and contamination of the final product can be suppressed.

The dehydrating agent is not particularly limited as long as it can accelerate the dehydrating reaction, but inorganic acids having strong acidity such as hydrochloric acid, sulfuric acid, hydrogensulfate, nitric acid, phosphoric acid, hydrogenphosphate and metaphosphoric acid, Strong Lewis acids such as zinc chloride, aluminum chloride, iron chloride, titanium chloride are preferred. Ammonium sulfate is most preferable in consideration of safety and machine materials. It is not clear why the above dehydrating agent is preferable,
It is considered that the strong acid has a stronger dehydration action and can be dehydrated at a low temperature even if the amount used is small. Further, when the treatment liquid is acidic and there is a problem in terms of safety and mechanical materials, a treatment liquid of ammonium salts neutralized with an organic amine such as ammonia may be used. By treatment with such a treatment liquid of ammonium salts, ammonia is scattered during heating, and an inorganic acid appears and acts effectively.
In the first aspect of the present invention, the amount of dehydrating agent used is 0.2.
It is carried out in the range of 1% by weight to 1% by weight.

The temperature, time, gas atmosphere and gas flow rate during dehydration are not particularly limited as long as they are conditions that can accelerate the dehydration reaction. These cannot be unconditionally specified because the optimum conditions differ depending on the type and amount of dehydrating agent used.However, if the temperature is higher than the melting point, melting will occur, so it is preferable to cause the dehydration reaction at a low temperature. Specifically, it is preferably used in the temperature range of 150 ° C to 250 ° C. Regarding the time, it is preferable to complete the treatment in a short time in consideration of productivity, and it is preferably about 20 seconds to 2 hours. The atmosphere is not particularly limited, but when heat storage is observed in the air, the oxygen concentration may be reduced or the atmosphere may be an inert gas atmosphere.

The conditions for attaching the dehydrating agent are not particularly limited, but it is said that the dehydrating agent and the PVA-based resin are uniformly mixed and then molded and uniformly dispersed, rather than being adhered by impregnation from the surface. It is preferable in terms. Further, when the method of impregnation from the surface is used, the form and higher order structure of the PVA-based resin are also important, and it is preferable that the shape is a differential shape rather than the chip shape, and the fiber is thinner than the one having a large fineness. It is preferable that the degree of chemical conversion is low, because uniform impregnation to the inside is easy. It is preferable to use PVA-based fibers as the PVA-based resin as a raw material or a molded product thereof.

The heat treatment step is not particularly limited as long as it can carbonize, and carbonization is usually achieved by treating at a temperature of 400 ° C. or lower in an oxidizing atmosphere. However, in the case of mass production, another problem of heat storage occurs depending on the oxidizing atmosphere conditions and temperature conditions. Therefore, from the viewpoint of preventing heat storage, it is more preferable to perform the heat treatment conditions as described below.

The gas flow rate per raw material input is 1 Nm ³ /
When heat treatment is performed by a batch method of hr · kg or more or a continuous method of gas flow rate per raw material input of 1 Nm ³ / kg or more, regarding the volume ratio of oxygen and the temperature at the time of heat treatment, a sufficient cross-linking structure for the carbonaceous material is required. It suffices that it can be introduced and that heat storage can be prevented. As such a heat treatment condition, for example, a heat treatment condition of 210 ° C. or lower is adopted when the treatment is carried out in air having a volume ratio of oxygen of about 21%. preferable. As will be described later, it has been revealed for the first time by the inventors of the present invention that heat storage can be prevented even if the heat treatment temperature is high by reducing the volume ratio of oxygen. Is 10%, it is preferable to adopt heat treatment conditions at 280 ° C. or lower, and when the volume ratio of oxygen is 5%, it is preferable to use heat treatment conditions at 330 ° C. or lower. 400
It is preferable to adopt heat treatment conditions at a temperature of not more than ° C.

However, as described above, the PVA resin is 2
Since it has a melting point near 00 ° C to 240 ° C, it will melt if it is heat-treated at a high temperature suddenly.
It is preferable to carry out the oxidation treatment at about 200 to 200 ° C. and then to add to the above temperature, or to maintain the temperature at about 180 to 200 ° C., perform the oxidation treatment, and then heat to the above temperature in a temperature rising manner. .

The heat treatment time is not particularly limited as long as a sufficient crosslinked structure can be introduced into the carbonaceous material and heat storage can be prevented. The heat treatment time cannot be unconditionally specified because it depends on the oxygen concentration and temperature used, but it is preferable to treat the heat treatment in the shortest time possible from the viewpoint of productivity. It is preferable to perform the heat treatment for 30 minutes to 10 hours. In order to complete the treatment in 30 minutes or less, it is necessary to perform the treatment at a high temperature and a high oxygen concentration, but such a formulation is not suitable because it easily accumulates heat, and the productivity is low even if the heat treatment is performed for 10 hours or more. Not the way.

In the present invention, the shape of the PVA-based resin or the molded product thereof is not particularly limited, and may be powdery, granular, film-like, plate-like, fibrous, non-woven fabric-like, paper-like or cloth-like depending on the use. There is such a thing, but it is selected appropriately,
From the viewpoint of suitable raw materials for obtaining industrially useful carbon fibers or activated carbon fibers, fibrous, non-woven, paper-like, and cloth-like are preferable. In the present invention, in particular, PV
A-based fibers are preferred.

The method for producing the PVA-based fiber is not particularly limited, but a known wet spinning method, dry-wet spinning method or dry spinning method can be adopted. The wet spinning method is P
This is a method in which a spinning solution containing a polymer solution obtained by dissolving a VA-based resin in an organic solvent or an aqueous solution obtained by dissolving a PVA-based resin in water is directly spun from a spinning nozzle into a solidification bath. 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 coagulation bath, the gas is caused to travel a specific distance, and then spun into a solidification bath. . The distance traveled cannot be decided unconditionally depending on the properties of the solidifying bath used, but is usually 1
It is carried out at about 50 m.

The wet spinning method in which the spinning nozzle is brought into direct contact with the solidifying bath to carry out 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. . It is preferable to appropriately select the spinning method as described above according to the purpose and use.

A second invention of the present invention is to use a PVA-based resin or a molded product thereof as a raw material, the raw material being in an atmosphere containing oxygen, and the gas flow rate per raw material input amount being 1 Nm ³ / hr · kg.
Above batch method or gas flow rate per raw material input is 1
It is a method for producing a carbonaceous material, characterized in that heat treatment is carried out by a continuous method of Nm ³ / kg or more.

It is possible to produce a carbon product using a PVA resin as a raw material without melting it by performing a heat treatment in an oxidizing atmosphere at a temperature of 400 ° C. or lower.
This is a known technique as described in Japanese Patent Publication No. 8-20353. However, the PVA-based resin is usually 200 ° C. to 240 ° C., though it depends on the saponification degree, the copolymer composition, and the like.
Since it has a melting point in the vicinity of ℃, if it is suddenly treated at a temperature higher than the melting point, it will melt, and the decomposition reaction will proceed rapidly, resulting in a decrease in yield. Therefore, PVA
Temperature below the melting point of the resin, specifically 180 to 200 ° C
It is also described that it is preferable to perform heat treatment in an oxidizing atmosphere in the vicinity to achieve infusibilization, but as described above, heat treatment for a very long time (15 hours or more) is required, and industrialization is performed. It is a hindrance to the situation.

Therefore, in order to suppress the melting of the PVA resin and enable the treatment in a short time, a dehydrating agent is used,
It is considered that the dehydration reaction is promoted by heat treatment at a temperature below the melting temperature of the system resin. However, even if a dehydrating agent is used, treatment under an oxidizing atmosphere for infusibilization is indispensable, and JP-B-45-31707 and JP-A-48-14 are used.
23, 49-24897, 50-35.
No. 431, No. 50-52320, No. 53-1.
Japanese Patent No. 14925 discloses that oxidation treatment is performed in the range of 180 ° C. to 340 ° C. However, detailed examination regarding an oxidizing atmosphere is not made, and only a formulation using air is disclosed. is there. Furthermore, the gas flow rate is not described in the examples.

The heat treatment in an oxidizing atmosphere is generally considered to promote the crosslinking reaction and dehydrogenation reaction by the oxidation reaction, and it is reported that it is effective for infusibilization.
It is considered that the same reaction also proceeds for the PVA resin, which contributes to infusibilization. It is considered that the higher the temperature, the faster the reaction proceeds, and the processing can be completed in a short time. However, as mentioned above, 4
At a temperature of 00 ° C or higher, the decomposition reaction by oxygen is accelerated, and the yield sharply decreases, so 180 ° C to 340 ° C.
It is described in JP-A-59-187624 that the heat treatment condition is adopted within the range of, and the heating time is preferably 180 ° C. for 10 hours and 340 ° C. for about 30 minutes. Therefore, the above suggests that the treatment at a high temperature may be performed in a short time.

However, when the present inventors conducted an additional test on a scale of several 100 g, it was found that heat was accumulated and an ignition occurred. Heat storage is a phenomenon in which the balance between the amount of heat generated and the amount of heat released is lost, and the amount of heat generated is large, so the temperature rises, and as a result, the exothermic reaction is accelerated, and the temperature rises repeatedly, causing an abnormal temperature rise. It is a phenomenon often seen in exothermic reactions, but it is a dangerous phenomenon because it may accompany ignition.

Since the oxidation reaction by oxygen is an exothermic reaction, a heat storage phenomenon easily occurs. It is considered that the higher the heating temperature, the faster the reaction and the more likely it is to occur, and the larger the charged amount, the more difficult it is to radiate heat. In the additional test by the present inventors, heat accumulation tends to occur as the heating temperature is higher and as the charged amount is larger. As for the shape, the fibrous shape was most likely to accumulate heat.

As a known technique, Japanese Patent Laid-Open No. 49-2489.
In JP-A-7, it is described that it is preferable to treat at a low temperature of 220 ° C. or lower in order to prevent heat accumulation, but it is difficult to say that it is realistic because treatment at a low temperature requires heating for a very long time. According to the study by the present inventors, when a large amount of raw material was charged, heat storage was observed even at 220 ° C. From this, it is considered that the high-temperature treatment recipe for shortening the time disclosed as a known technique causes heat storage in the case of a large scale, so that practical application is practically impossible. As described above, in heat treatment in an oxygen atmosphere, almost no study has been made on a heat storage prevention formulation.

Therefore, the present inventors conducted a study by focusing on the gas flow rate, which has not been noticed by the known technique, in order to find out the conditions for producing a large amount of carbonaceous material in a short time. Completed the invention. In the present invention, when the batch method is adopted, the gas flow rate per raw material input amount is 1N.
It is carried out at m ³ / hr · kg or more, and when the continuous method is adopted, the gas flow rate per raw material input amount is carried out at 1 Nm ³ / kg or more.

Although it is not clear why this gas flow rate is very effective in suppressing heat storage and achieving infusibilization in a short time, it is possible to always maintain a fresh atmosphere by flowing gas. , The oxygen concentration is always constant, so the reaction rate is stable, the infusibilization process is completed in a short time, and heat dissipation is promoted by flowing gas,
It is presumed that it is also effective in preventing livestock heat. Also, by flowing gas, water that is thought to be generated from the raw materials,
Because it is effective in removing generated gases such as aldehydes,
It also contributes to the improvement of product quality.

The batch method in the present invention is a method in which raw materials are charged into a reaction vessel, an oxidation reaction is carried out, and after the reaction is completed, the raw materials are cooled and taken out, and are often used for powdery raw materials.
The continuous method is a method in which a raw material is fed at a certain speed and is retained in an oxidation furnace for a certain period of time, and is often used for a fibrous raw material. The gas flow rate is very important for both methods.

In the case of the batch method, the gas flow rate per raw material input amount can be calculated by dividing the used gas amount per hour by the raw material input amount. If the gas flow rate per raw material input is too small, it becomes difficult to remove the gas generated from the raw material, and it is thought that the contact with oxygen is blocked. It takes a long time, and when a large quantity is charged,
The unevenness of the infusibilization is likely to occur. Moreover, even if the gas flow rate is increased too much, it has little effect on the infusibilization process, the equipment becomes large-scaled, and the cost only increases, so the gas flow rate per raw material input amount is 1
~ 500 Nm ³ / hr · kg is preferable, and 5 to 3
More preferably, it is set to 00 Nm ³ / hr · kg. The exhaust gas may be exhausted as it is, or may be continuously used by circulating the gas while trapping impurities contained therein.

In the case of the continuous system, the gas flow rate per raw material input amount can be calculated by dividing the used gas amount per hour by the raw material input amount per hour.
For the same reason as described above, the gas flow rate per raw material input amount is 1 to 500 Nm ³ /
It is preferable to set it as kg, and it is 5 to 300 Nm ³ / hr · kg.
Is more preferable.

As described above, the importance of the oxygen concentration has not been paid attention to by the known technique, but the oxygen concentration is
This is a very important factor in shortening the heat treatment time while preventing heat accumulation. In the second invention of the present invention,
When producing a carbonaceous substance using a PVA-based resin or a molded product thereof as a raw material, the raw material is made to have an oxygen concentration of 0.5% by volume or more and 15% by volume or more.
It is preferable to perform heat treatment in an atmosphere of an oxygen-containing gas of not more than volume% because heat storage can be prevented and a large amount of infusibilizing treatment can be performed in a short time.

The purpose of the oxidation treatment is to make the raw material infusible, and it is ideal to perform a large amount in the shortest possible time.
According to the study results of the present inventor, it is preferable to perform high temperature treatment with high oxygen concentration in order to perform treatment in a short time, but it is easy to accumulate heat,
When low-temperature treatment is performed at a low oxygen concentration, heat storage can be avoided, but long-term treatment is required. Therefore, in order to perform a large amount of treatment in a short time, it is important to balance the amount of raw material charged, the oxygen concentration, the heat treatment temperature, and the time. When the oxygen concentration is low, the high temperature treatment is preferable, and when the oxygen concentration is high, the low temperature treatment is performed. Treatment is preferred.

As described above, a specific oxygen concentration is preferably 0.5% by volume or more and 15% by volume or less, and more preferably 3% by volume or more and 10% by volume or less. It is not clear why the above oxygen concentration is effective in exhibiting the effect of suppressing heat storage and achieving infusibilization, but if the oxygen concentration is 0.5% by volume or less, the oxidation reaction rate is very slow, which is unsatisfactory. Diffusing treatment is difficult, and
Since oxygen is consumed in the reaction, in the case of the continuous system, it is assumed that the difference in concentration between the gas introduction part and the gas discharge part becomes remarkable and is likely to cause spots. Conversely, when the oxygen concentration becomes 15% by volume or more. It is conceivable that the oxidation reaction or decomposition reaction that does not contribute to the infusibilization progresses and the heat storage becomes remarkable.

The method of controlling the oxygen concentration is not particularly limited, but it is convenient and preferable to control it by mixing air and an inert gas. As the inert gas, nitrogen, argon, helium, carbon dioxide,
Water vapor may be used, and a mixed gas of oxygen, nitrogen, carbon dioxide, and water vapor, which is produced by adjusting the mixing ratio of propane and air and burning it, can also be used.

The heat treatment temperature and heat treatment time are not particularly limited as long as a sufficient crosslinked structure can be introduced into the carbonaceous material and heat storage can be prevented. These cannot be unconditionally specified because they differ depending on the oxygen concentration used, but the above-mentioned conditions can be applied, and the heat treatment time is shortened as the temperature is increased.

In the second invention, in order to achieve infusibilization more efficiently in a shorter time, it is preferable to use a PVA-based resin having a dehydrating agent attached thereto or a molded product thereof as a raw material. The use of a PVA-based resin having a dehydrating agent attached thereto or a molded product thereof as a raw material is known as described above, and the dehydration reaction of the PVA-based resin having a dehydrating agent attached progresses at a temperature below the melting point. Therefore, the infusibilization up to 400 ° C. can be easily achieved by performing the heat treatment around the dehydration start temperature. Therefore, P with a dehydrating agent attached
It is known that the use of a VA-based resin can greatly simplify the pretreatment at around 200 ° C. and can efficiently dehydrate, thereby improving the yield.

However, since melting occurs at a temperature of 400 ° C. or higher, the infusibilizing treatment under an oxygen atmosphere is indispensable, but as described above, there is a problem of heat storage, and it is necessary to control the gas flow rate or the oxygen concentration. By combining them, it becomes possible to perform a large amount of infusibilizing treatment in a short time while further suppressing heat storage. When a dehydrating agent is used, the conditions described above can be applied to various conditions of oxidation treatment, gas flow rate, oxygen concentration, and temperature, and the dehydration treatment can significantly reduce the time. .

The amount of the dehydrating agent used is not particularly limited as long as it can accelerate the dehydration reaction. The amount of dehydrating agent used cannot be unconditionally specified because the optimum amount varies depending on the type of dehydrating agent, but it is usually 0.1% by weight to 20% by weight.
Often used in. However, when producing carbonaceous substances, these dehydrating agents decompose and volatilize in exhaust gas, causing equipment corrosion, or remain as contamination and adversely affect the product. Is preferably reduced, and is preferably performed in an amount of 0.2% by weight or more and 1% by weight or less. The temperature, time, gas atmosphere, gas flow rate, and deposition conditions during dehydration are the same as those described in the first invention. In addition, it is preferable to use PVA-based fibers as the PVA-based resin as a raw material or a molded product thereof.

Next, the third invention of the present invention will be described. A third invention is a method for producing a carbonaceous material, which comprises using a PVA-based resin or a molded product thereof as a raw material, and heat-treating the raw material in an oxygen-containing gas of 0.5% by volume or more and 15% by volume or less. is there. As described above, the importance of the oxygen concentration has not been paid attention to by the known technology, but it is very important for shortening the heat treatment time while preventing heat accumulation. The oxygen concentration is preferably 0.5% by volume or more and 15% by volume or less, and more preferably 3% by volume or more and 10% by volume or less. For how to control the oxygen concentration,
This is as described in the second invention.

In the third invention, in order to achieve infusibilization efficiently in a shorter time, it is preferable to use a PVA resin to which a dehydrating agent is attached or a molded product thereof as a raw material. However, since melting occurs at a temperature of 400 ° C. or higher, infusibilizing treatment under an oxygen atmosphere is essential, and there is a problem of heat storage as described above, and by combining control of gas flow rate or oxygen concentration, A large amount of infusibilization processing can be performed in a short time while suppressing heat storage. The dehydrating agent used is the same as that described above, and the amount of the dehydrating agent used is 0.1% by weight or more and 20% by weight or more.
The following is preferable, and 0.2 wt% or more and 1 wt% or less is more preferable. It is preferable to use PVA-based fibers as the PVA-based resin as a raw material or a molded product thereof.

The combination of the first invention, the second invention and the third invention of the present invention described above is the best mode for producing a carbonaceous substance using PVA and the activated carbon described later. Become. That is, a polyvinyl alcohol-based resin or a molded product thereof having a dehydrating agent attached in an amount of 0.2% by weight or more and 1% by weight or less is used as a raw material, and the raw material is supplied in an atmosphere containing oxygen with a gas flow rate of 1 Nm ³ per raw material input. / hr ・ k
A carbonaceous material is produced by heat treatment in an oxygen-containing gas of 0.5% by volume or more and 15% by volume or less by a batch system of g or more or a continuous system with a gas flow rate per raw material input of 1 Nm ³ / kg or more. Is the most preferred method.

A manufacturing method according to the first to third inventions;
Alternatively, the carbonaceous substance which is the fourth invention of the present invention obtained by the production method of the best mode in which these are combined is, by itself, various electrode materials, electrically conductive materials, heat insulating materials, adsorption materials, flameproof materials, electrified materials. It is preferably used as a preventive material, heat resistant material, chemical resistant material and the like. Further, the carbon material may be heat-treated or activated in a non-oxidizing gas atmosphere to obtain a carbon fiber or a graphite material, or activated carbon.

The carbonaceous material obtained in the present invention is further subjected to heat treatment if necessary. The heat treatment after the heat treatment under the oxidizing atmosphere is roughly classified into a method of gradually increasing the temperature from a low temperature and a method of suddenly introducing the temperature to a high temperature. The method of gradually increasing the temperature from a low temperature is often used in the production of carbon fibers and the like, and an atmosphere of an inert gas such as nitrogen or argon is adopted as the atmosphere. Further, the method of suddenly introducing into high temperature is often used in the case of producing activated carbon, activated carbon fiber or the like, and the atmosphere is an atmosphere of activated gas containing water vapor, carbon dioxide gas, trace amount of oxygen and the like. Industrially, prescriptions using steam, carbon dioxide, etc., which are produced by burning LPG gas such as propane, are often used.

As described above, when the carbonaceous material is produced by using the PVA-based fiber, the obtained fibrous carbonaceous material is heat-treated in a non-oxidizing gas atmosphere to obtain heat resistance, heat insulation and conductivity. A carbon fiber having excellent properties and the like can be obtained. The heat treatment conditions are appropriately selected depending on the desired performance of the carbon fiber, but usually, in an inert atmosphere, 1000 ° C to
It is processed at 1400 ° C. Further, the tensile elastic modulus of the carbon fiber can be remarkably improved by performing a heat treatment at a high temperature, that is, a so-called graphitization treatment. Graphitization conditions are usually 2000 ° C to 3000 ° C in an inert atmosphere.
It is carried out in.

The activated carbon according to the fifth aspect of the present invention can be obtained by subjecting the carbonaceous material of the present invention to heat treatment in an atmosphere of an appropriate oxidizing gas, that is, so-called activation treatment. In this case, powdery activated carbon can be obtained by using a powdered PVA-based resin as a raw material, and film-shaped activated carbon can be obtained by using a film-shaped PVA-based resin. If a fibrous PVA-based resin is used, activated carbon fibers can be obtained. Activated carbon fiber has a significantly larger macro contact area than granular or powdered activated carbon, has a high adsorption rate, does not generate dust, and has many advantages such as low pressure loss. It is useful for etc. In this case, fibrous PVA
By molding the system resin and making the raw material into a non-woven fabric, paper-like, cloth-like or the like, non-woven fabric-like activated carbon, paper-like activated carbon, cloth-like activated carbon or the like can be easily obtained.

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 a steam or carbon dioxide atmosphere, it is usually 500 to 1200 ° C., preferably 700.
The activation treatment may be performed at a temperature of from 1000 to 1000 ° C. for several minutes to several hours. When a combustion gas of propane gas is used, the activation treatment is from 800 to 120.
High temperature rapid activation can also be performed at 0 ° C. Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

[0077]

EXAMPLES Reference Example 1 PVA having a degree of polymerization of 1700 and a degree of saponification of 99.9 mol% was added to water, and dissolved by stirring at 80 ° C. under a nitrogen gas stream to obtain PVA.
A spinning dope having a concentration of 16% by weight was prepared. The spinning solution is
40 consisting of 30 wt% sodium sulfate aqueous solution through 4 spindles of spinning nozzle with a hole diameter of 0.07 mm and a hole number of 24000
It was spun in a solidifying bath at ℃ and spun wet. Obtained PVA
Immerse the fiber in the same solidifying bath for 1 minute, draw it 2.5 times, and
It was dipped in a 35 wt% sodium sulfate aqueous solution at 0 ° C. for 1 minute, stretched in a saturated sodium sulfate aqueous solution at 90 ° C. so that the total stretching ratio was 4.5 times, and dipped in the same bath for a fixed length of 30 seconds.

Then, after washing with water at 10 ° C. for 2 minutes under running water to remove sodium sulfate, the solution is introduced into an ammonium sulfate aqueous solution bath at 25 ° C. and 1 wt% (ammonium sulfate and sulfuric acid in the total amount of water) of ammonium sulfate. Hold for 5 minutes, PVA
After impregnating the surface and inside of the fiber with ammonium sulfate as a dehydrating agent, the fiber was dried with hot air at 100 ° C. and wound up. Then, the dried PVA fiber was heated in a first furnace at 170 ° C., 20
Hot drawing was carried out in a hot air oven consisting of a second furnace at 0 ° C. so that the total draw ratio was 7 times. The fineness of the obtained Itoshino is 200,000 dte.
x, and the content of ammonium sulfate in the fiber was 0.6 parts by weight.

Reference Example 2 Spinning was performed in the same manner as in Reference Example 1 except that the concentration of the aqueous solution of the dehydrating agent was changed to 10% by weight, to produce PVA fiber having an ammonium sulfate content of 6.5% by weight.

Example 1 The fiber obtained in Reference Example 1 was mixed with 5% by volume of oxygen-containing mixed gas at a gas flow rate of 40 Nm ³ / kg to obtain 0.04 g / d.
A dehydration treatment was performed at 220 ° C. for a total heat treatment time of 4 minutes while applying a tension of tex. The dehydrated fiber obtained was blackish brown, and the weight yield based on PVA was 76% by weight.

The dehydrated fiber thus obtained was carbonized by heat-treating (infusibilizing) for 50 minutes at 290 ° C. and a gas flow rate of 40 Nm ³ / kg in a mixed gas containing 5% by volume of oxygen. The obtained black carbonaceous fiber was very flexible, and the weight yield was 57% by weight.

Next, the black carbonaceous fiber was treated with propane combustion gas (mainly composed of H ₂ O and CO ₂ ) at 930 ° C. for 30 times.
Rapid activation treatment was performed for a minute. 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 fibers was 15% by weight, the BET specific surface area measured by the nitrogen adsorption amount was 1590 m ² / g, and the I ₂ adsorption amount measured according to JIS K1474 was 1640 mg / g. When 50 mg of activated carbon fiber was completely burned in a closed flask and trapped in an aqueous solution and sulfur was measured by ion chromatography, 30 ppm in terms of elemental sulfur was detected.

Example 2 Example 1 was repeated except that the raw material was changed to Reference Example 2. The weight yield of fibrous activated carbon with respect to the raw material fiber is 16
The BET specific surface area measured by weight% and nitrogen adsorption amount is 160
0 m ² / g, I measured according to JIS K1474
_{The 2} adsorption amount was 1690 mg / g. Activated carbon fiber 5
When 0 mg was completely burned in a closed flask and trapped in an aqueous solution and sulfur was measured by ion chromatography, 540 ppm in terms of sulfur element was detected.

Examples 3 to 4 The same procedure as in Example 1 was carried out except that the raw material fibers and the carbonization treatment gas flow rate conditions were changed as shown in Table 1. The results are shown in Table 1.

[0085]

[Table 1]

Example 5, Comparative Example 1 The same procedure as in Example 1 was carried out except that the raw material fibers, the gas flow rate for carbonization, the oxygen concentration, the temperature and the time conditions were changed as shown in Table 2. The results are shown in Table 2. In Comparative Example 1, the infusibilizing treatment was not sufficient, and it melted during the activation treatment.

[0087]

[Table 2]

Example 6, Comparative Example 2 The activation treatment method was carried out in a combustion gas of propane (mainly composed of H ₂ O and CO ₂ ) at 300 ° C. to 600 ° C. at a temperature of 20 ° C./minute, and then at 930 ° C. for 30 minutes. Table 3 shows the conditions of oxygen concentration, temperature, and time for carbonization after changing to the heating activation method of heat treatment for minutes.
The same procedure as in Example 1 was carried out except that the above was changed. The results are shown in Table 3. In Comparative Example 2, heat was stored because the balance between the oxygen concentration and the heat treatment temperature was lost.

[0089]

[Table 3]

[0090]

INDUSTRIAL APPLICABILITY According to the present invention, a method for producing a carbonaceous substance, which comprises heat-treating a polyvinyl alcohol-based resin having a dehydrating agent deposited in an amount of 0.2% by weight or more and 1% by weight or less, or a molded product thereof, as a raw material, polyvinyl alcohol Using a system resin or a molded product thereof as a raw material, and using the raw material under an atmosphere containing oxygen, the gas flow rate per raw material input amount is 1 Nm ³ / hr · kg or more, or the gas flow rate per raw material input amount is 1 Nm ³
/ Kg or more continuous heat treatment method for producing a carbonaceous material, and polyvinyl alcohol resin or a molded product thereof as a raw material, the raw material 0.5% by volume
It is possible to provide a method for producing a carbonaceous material, which is characterized by performing heat treatment in an oxygen-containing gas of 15% by volume or less. Carbonaceous substances obtained by these production methods and activated carbon obtained by activating the carbonaceous substances are various electrode materials, conductive materials, heat insulating materials, adsorbent materials, flameproof materials, antistatic materials, heat resistant materials, and It is suitable for use as a chemical material.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) D01F 9/21 531 D01F 9/21 531 F term (reference) 4G066 AA04B AA04C AA47D AC12A BA16 BA26 CA02 CA10 CA43 CA51 DA02 DA03 DA07 DA08 FA22 FA25 FA37 FA40 4G146 AA06 AB06 BA13 BC01 BC24 BD05 4L037 AT11 CS03 CS06 FA01 PA46 PC06 PC08 PS03 PS12 PS17 UA01 UA04 UA07

Claims (13)

[Claims] 1. A method for producing a carbonaceous material, which comprises heat-treating a polyvinyl alcohol-based resin or a molded product thereof, to which a dehydrating agent is attached in an amount of 0.2% by weight or more and 1% by weight or less, as a raw material. 2. The method for producing a carbonaceous material according to claim 1, wherein the raw material is polyvinyl alcohol fiber. 3. A polyvinyl alcohol-based resin or a molded product thereof is used as a raw material, and the raw material is supplied in an atmosphere containing oxygen with a gas flow rate per raw material input amount of 1 Nm ³ / hr · kg or more per batch method or per raw material input amount. Gas flow rate of 1Nm ³
A method for producing a carbonaceous material, characterized in that the heat treatment is performed by a continuous method of not less than 1 kg / kg. 4. The method for producing a carbonaceous material according to claim 3, wherein the atmosphere containing oxygen is a gas containing 0.5% by volume or more and 15% by volume or less of oxygen. 5. The polyvinyl alcohol-based resin to which a dehydrating agent is attached, or a molded product thereof, as the raw material.
A method for producing the carbonaceous material described. 6. The method for producing a carbonaceous material according to claim 5, wherein the attached amount of the dehydrating agent is 0.2% by weight or more and 1% by weight or less. 7. The method for producing a carbonaceous material according to claim 3, wherein the raw material is polyvinyl alcohol fiber. 8. A polyvinyl alcohol resin or a molded product thereof is used as a raw material, and the raw material is 0.5% by volume or more and 15% by volume.
A method for producing a carbonaceous material, which comprises performing heat treatment in an oxygen-containing gas as described below. 9. The method for producing a carbonaceous material according to claim 8, wherein the raw material is a polyvinyl alcohol resin to which a dehydrating agent is attached or a molded product thereof. 10. The method for producing a carbonaceous material according to claim 8, wherein the amount of the dehydrating agent attached is 0.2% by weight or more and 1% by weight or less. 11. The method for producing a carbonaceous material according to claim 8, wherein the raw material is polyvinyl alcohol fiber. 12. A carbonaceous substance obtained by the manufacturing method according to claim 1. 13. Activated carbon obtained by activating the carbonaceous material according to claim 12.