CA1324469C - Process for producing carbon materials - Google Patents
Process for producing carbon materialsInfo
- Publication number
- CA1324469C CA1324469C CA 574485 CA574485A CA1324469C CA 1324469 C CA1324469 C CA 1324469C CA 574485 CA574485 CA 574485 CA 574485 A CA574485 A CA 574485A CA 1324469 C CA1324469 C CA 1324469C
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- CA
- Canada
- Prior art keywords
- raw material
- carbon materials
- material composition
- producing carbon
- spun
- Prior art date
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Classifications
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
- D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
- D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
- D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
- D01F9/20—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products
- D01F9/24—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Inorganic Fibers (AREA)
- Carbon And Carbon Compounds (AREA)
- Artificial Filaments (AREA)
- Separation Of Gases By Adsorption (AREA)
Abstract
ABSTRACT
Disclosed is a process for producing carbon materials which comprises the steps of preparing a raw material composition by mixing a methylene type linkage-containing condensation product of an aromatic sulfonic acid or a salt thereof with a solvent, the condensation product having been formed by means of a linkage of the formula -(CH2)n-Tx-(CHR)m- (1) where T is a benzene or naphthalene ring, R is a hydrogen atom, an alkyl group of 1 to 4 carbon atoms, or a benzene ring, and each of n, m and x is 0 or 1, but n and m should not be zero at the same time; spinning or molding the raw material composition; and carbonizing the spun fiber or molded article. Preferably, the aforesaid linkage is-CH2-.
Disclosed is a process for producing carbon materials which comprises the steps of preparing a raw material composition by mixing a methylene type linkage-containing condensation product of an aromatic sulfonic acid or a salt thereof with a solvent, the condensation product having been formed by means of a linkage of the formula -(CH2)n-Tx-(CHR)m- (1) where T is a benzene or naphthalene ring, R is a hydrogen atom, an alkyl group of 1 to 4 carbon atoms, or a benzene ring, and each of n, m and x is 0 or 1, but n and m should not be zero at the same time; spinning or molding the raw material composition; and carbonizing the spun fiber or molded article. Preferably, the aforesaid linkage is-CH2-.
Description
PROCESS FOR PRODUCING CARBON MATERIALS
BACRGROUND OF THE INVENTION
. . .
1) Field of the Invention:
' 5 This invention relates to a process for producing carbon materials whicb can be used either in - ::
the form of fibers or va3ious molded articles as fillers for various composite materials, heat insulating mate-rials and ablation materials, or in the form of activated carbon materials including molecular sieve carbon materials, activated carbon fibers and the like as adsorbent or separating materials.
BACRGROUND OF THE INVENTION
. . .
1) Field of the Invention:
' 5 This invention relates to a process for producing carbon materials whicb can be used either in - ::
the form of fibers or va3ious molded articles as fillers for various composite materials, heat insulating mate-rials and ablation materials, or in the form of activated carbon materials including molecular sieve carbon materials, activated carbon fibers and the like as adsorbent or separating materials.
2) Description o~ the Related Art:
Among carbon materials in such fibrous forms as generall~ called carbon fibers, molecular sieve `-`
carbon fibers or activated carbon fibers, carbon fibers are produced by spinning rayon, lignin, polyacrylonitrile _ ~herainafter referred to as PAN~, pitch or the like, 20 rendering the spun fiber infusible, carboni2ing it at `
a temperature of 1,000 to 1,600C,,or further graphitiz- ;
ing the resulting carbon fiber at a temperature of :~
2,000 to 3,000C. On the other hand, molecular sieve :~
. ~.
carbon fibers and activated carbon fibers are produced 25 either by spinning a raw material as described above, ` .
~ ` ' "
~ .''. . ':
:~ ...,, :...
l 32446q rendering the spun fiber infusible, and then activating it, or by rendering the spun fiber infusible, carbonizing it, and then activating the resulting carbon fiber.
Although these carbon materîals in fibrous form have excellent properties which are not possessed by other materials, they involve`several operational problems as described in~the f~llowing paragraphs (1) to ~3). Therefore, these carbon materials are high in price and still far from being widely used as common industrial materials~
(1) In order to provide industrially practicable spinnability, the spinning material must previously be freed of any for~ign matter by hiqh-precision filtration.
(2) Rayon and PAN are spun according to the wet or dry spinning te~hnique, which involves the cost of solvent recoYery. On the other hand, the spinning of lignin and pitch produces tar and mist, so that it is important to control the spinning atmosphere.
_ 20 (3) All of the fibers spun from the aforesaid raw ~.
materials require a treatment for rendering them - -infusible. Generally, this treatment is carried -out by air oxidation. In,this treatment, a long treating time, l~rge-capacity oxidizing equipment and the like are needed to prevent violent exothermic reaction, i.e., combustion. -`
:
In order to eliminate the time-consuming step of rendering the spun fiber infusible by air oxidation, there has been proposed a process in which fibrous polystyrene is soaked in sulfuric acid and then carbonized (Japanese Patent Publication No. 36085/'86). However, this process has the disadvantage that the sulfonation of polystyrene (i.e., the introduction of sulfonic groups into polystyrene) is not ~ffected uniformly throughout the entire fiber. That is, spots rendered infusible, spots made fragile due to excessive sul~onation, and spots not rendered infusible are formed in the fiber surfaces, resulting in a very inhomogeneous ~iber.
, ~
SU~NARY OF THE INVENTION
lS It is the primary ob~ect of the present in~ention to provide a process for producing carbon `
ma~erial~ by ~hich the abovè-described problems of the prior art can be solved and in which carbon materials ha~ng the form of fibers or molded articles (such as honeycQmbs) and useful as components for various composite materials and as adsorbent or separating materials can be produced by easy and simple operation.
In view of ~he above and other objects, the present inventors have made an intensive inveatigation and have found that the above-described problems can be solved by using a methylene type linkage-containing condensation product of an aromatic sulfonic acid or a salt thereof as the spinning or moldinq material. The present invention has been completed on the ~asis of this finding.
According to the present invention, there is provided a process for producing carbon materials which comprises the steps of p~eparing a raw material -composition comprising a methylen type linkage-containing condensation product of an aromatic sulfonic acid or a salt thereof and a solvent, the condensation product having been formed by means of a linkage of the formula -(CH2)n-Tx (CHR~m (1) where T is a benzene or nap~hthalene ring, R is a hydrogen atom, an alkyl group of 1 to i carbon atoms, or a ben~ene ring, and each of n, m and x is 0 or 1, but n and m should not be zero at the same time; spinning or molding the raw material composition; and carbonizing the spun fiber or molded article.
~ ~ .
DETAIL~D DESCRIPTI~N OF THE IN~ENTION
_ Specific examples of the aromatic sulfonic ~ -acid, or salt thereof, which is used in the present invention include naphthalenesulfon~c acid, anthracene-sulfonic acid, phenantbrenesulfonic acid, sulfonated . .
~ , . ' ~ . ~ ' . . ' products of polycyclic aromatic compound mixtures (such as creosote oil, anthracene oil , tar and pitch), toluenesulfonic acid, xylenesulfonic acid, sulfonated phenols and mixtures thereof, as well as salts of the foregoing. These aromatic sulfonic acids can be : obtained by sulfonàting the corresponding àromatic compounds according to an~ of vario~s well-known methods.
Although ~he cation constituting salts of the aromatic sulfonic acids can be Na~, K~, Ca~2, NH4~ and the like, 10 ammonium salts are preferred because of the ease with ~ ~`
~hich the spun fiber can be handled in the carbonization step. Moreover, preferred salts may vary according to the desired type of carbon material. That is, ammonium salts are preferred for the productàon of carbon -materials re~uirin~ strength. In order to produce porous adsorbent materials or separating materials, ` `
ammonium salts can be used satisfactorily, but sodium and calciu~ salts are more preferred.
Condensation product~ of the above-described `` 20 aromatic sulfonic acids or salts thereof can be prepared according to any of various well-known methods. However, it is common practice to condensate an aromatic sulfonic acid or a salt thereo~ with the aid of formalin, `
paraformaldehyde, hexamethy}enetetramine or other aldehyde. It is also possible to use a methylene type linkage-containing polymer (such as polystyrenesulfonic acid) obtained by polymerizing an aromatic sulfonic acid having a vinyl group. Although the linkage connect-ing molecules of the aromatic sulfonic acid may be any of the linkages within the scope of formula (1), the -CH2- linkage is especially preferred because ` methylene-linked condensation products are easy to prepare or obtain. And ~he linkage in a methylene type linkage-containing condensation product of an aromatic sulfonic acid or a salt thereof as said in the present invention, includes not only those which connect directly with an aromatic ring but also those which connect by means of side chains as in the case of a polystyrenesulfonic acid.~
Various types of condensation products can be obtained, depending on the type of aromatic compound us~d, the conditions of sulfonation and condensation reactions, and the like. Of course, these condensation pr~ducts may be used alone or in admixture of two or more, and may also be used in the form of polycondensation _ 20 products.
As an example of the methylene type linkage-containing condensation product of aromatic sulfonic acid, or salt th~reof, which is used in the process of the present invention, mention is made of a condensation product obtained by condensing ammonium naphthalene-~-sulfonate with the aid of formaldehyde. This condensation ' .:`
. ,"., ~; ;; .
1 32446q product is a mixture of monomer and various polymers having polymerization degrees of up to about 200, and has a number-average molecular weight of about 2,000 to 50,000. This condensation product is a solid at ordinary temperatures, sparingly soluble in organic solvents such as benzene,~toluene and acetone, and readily soluble in aqueous solvents. A 60~ ~w/w) aqueous solution thereof~has a viscosity of about 10 to 20,000 poisas at 60C and exhibits adequate `.
10 spinnability and moldability. When this condensation .
product is carbonized at a temperature of 800 to 1,000C, the yield of the resulting carbon material is .. ~: .... .
about 50% by weiqht~
The above-described condensation product is only one example of the condensation products useful in the process of the present invention, and it is to be understood that the range of the polymerization de~ree, or number-average molecular weight, of a : .
condensation product useful in the process of the present 20 invention depends on the type of the aromatic sulfonic acid, or salt thereof, constituting the condensation product. For example, a useful condensation product ~ :
of sulfonated creosote oil is a mixture of monomer and various polymers having polymerization degrees of ~.
25 up to about 40, and has a number-average mo~ecular ~:
weight of about 2,000 to about 5,000. A useful ~;
' :
~' ':' ' .
condensation product of phenanthrenesulfonic acid is a mixture of monomer and various polymers having polymerization degrees of up to about 30, and has a number-average molecular weight of about 2,500 to about 5,000.
T~e above-definèd condensation product or polymer of aromatic sulfonic acid or salt thereof is dissolved or dispersed i~p~a solvent to prepare a raw material composition. If necessary, the viscosity of this raw material composition is adjusted by suitable means such as dilution and concentration. Then, the ra~ material composition is spun into fibrous form or molded into any desired shape such as block, column, plate, film or honeycomb. Finally, the spun fiber or molded article is carbonised to obtain a carbon material.
In view of the properties of t~ë condensation product or polymer of aromatic sulfonic acid or salt thereof, the solvent used in the process of the present _ 20 invention is preferably selected from polar solvents `
including water, alcohols (such as methanol), aceto-nitrile and the like. Among others, it is most preferable to use water or an aqueous solvent comprising a mixture of water and a suitable water-soluble solvent.
Where a carbon material in fibrous ~orm is to be produced by the process of the present invention, it -g is undesirable that the aromatic sulfonic acid used as the raw material contains a high proportion of unsulfonated aromatic compounds, because they make -the resulting carbon fibers inhomogeneous and cause a reduction in strength. In such a case, the methylene type linkage-containing condensation products of unsulfonated aromatic cQ~pounds can be removed by .
using water as the solve~nt. That is, since the methylene-linked condensation products of unsulfonated aromatic compounds àre hardly soluble in water and, therefore, can be separated from the spinning solution .`
i~ according to suitable techniques such as filtration, .
centrifugation and dialysis. Moreover, the use of an agueous solvent is preferred from operational points `.`
of view, because the spinning atmosphere can be controlled easily.and there is no risk of ignition or explosion.
In the process of the present invention, the . .
spinnability and moldability of the raw material ` ;
composition can further be improved by adding a water~
soluble polymeric compound, as a spinning or molding aid, to the raw material composition in an amount of :
0.02 to 20 parts by weight per 100 parts by weight .:
of the solid constituent of the raw material composition.
25 The water-soluble polymeric compound used in the present~ .
invention can be any of various polymeric compounds ~.
that are soluble or colloidally dispersible in water and aqueous solvents. Especially preferred are poly-alkylene oxid~ compounds such as condensation products of ethylene oxide, propylene oxide, etc., and condensa-tion products obtained by ~he reaction of these compounds : with various alcohols, fatty acids, alkylamines andalkylphenols; polyvinyl cQmpounds such as polyvinyl alcohol and polyvinyl py~rolidone; polyacrylic compounds such as polyacrylic aci~, polyacrylamide and acrylic acid-acrylamide copolymer; and the like. Among the methylene-linked condensation products of aromatic sulfonic acids, or salts thereof, which can be used as the raw material in the process of the present invention, those having high solubility in water ~such as poly-styrenesulfonic acid) can also be used as the water-so}uble polymeric compound. The addition of such a ~ater-soluble polymeric ~ompound is effective in ~`
accelerating the spinning speed, making it easy to ` `
handle the spun fiber or molded article prior to 20 carbonization, and increasing the strength of the resulting carbon fiber or molded product. If the amount of water-soluble polymeric compound added is less than 0.02 part by weight, a satisfactory effect cannot be obtained. If it is greater than 20 parts by weight, the fiber or the }ike is liable to fusion during the heating operation for carbonization. This is undesirable because a separate step of rendering it infusible is required.
As described above, the methylene type linkage-containing condensation product of aromatic sulfonic acid or salt thereof, which is used in the process of : th`e present invention, can be spun or molded and then carbonized to produce ca~bon materials in fibrous form and in various other forms. However, on the basis of `~
the feature that the aforesaid condensation product can be carbonized without being rendered infusible, the process of the present il~vention is particularly suitable for the production of caxbon materials in fibrous form.
The content of the condensation product in the raw material composition for spinning ~i.e., the 15 spinning material) may vary according to the types of :
the condensation product~ water-soluble polymeric co~pound and solvent. ~owever, it is qenerally in the ` `
r~nge of 20 to 80~ by weight and preferably in the range o~ 40 to ?0~ by weight.
_ 20 In the spinning material liquid there are sometimes produced impurities from the raw materials or derivative substances, whether in solid or gel, resulted from reaction by-products among the raw matèrials. -The removal of such i~purities or substances is effective in gaining a high-spinnability or an improved q~ality of carbon materials in fibrous form. Though it can be made outside a spinning machine, the removal can be far effectively carried out by placing a sintered metal filter, a sintered metal fibrous filter, a sintered metal wire netting filter or a pack filter of various metal fillers upon a spinneret.
The spinning temperature may vary according to the composition of t~è spinning material, the desired shape of fiber, and the like. However, where water is used as the solvent, the spinning temperature is preferably in the range of 20 to 100C. The fiber emerging from the spinnerlet is drawn out by means of a wind-up roll, godet rolls, an air sucker or the like, is wound up or is accumulate~ in a receiver after having been dried within a barrel dryer equipped under the spi~neret, preferably in a heated-air stream flowing in parallel to the progress of the ~iber. A draft ratio ~i.e., the spinneret's di~meter/the spun fiber's diameter) where thè fiber is drawn out, can be 100 to 2; however, a preferable range of it is 10 to 5. A 20 fiber ~ith a big surface can be also produced by apply-ing a spinneret of irregular form in order to ease the drying of the fiber and enhance the fibrous strength. -Although the diameter of the spun fiber may be determined aribitrarily, it is preferably in the range of 2 to 100 , .
25 ~m and more preferably in the range of 8 to 20 ~m. `
There is a possibility that the spun fiber .
might absorb humidity and melt into another one because of its hygroscopicity if it is left for a long time in the open air. Accordingly, it is favorable soon to send the spun ~iber to the carbonization process or to stock it in the dry air when necessary.
According to the process of the present invention, the spun fiber can be carbonized without being rendered infusible~ In the carbonization process the spun fiber is fired by heating at a thermal ascending speed of 1 to 2,000C/min., preferably 10 to 500C/min., up to a temperature of 500 to 2,000C, but under a -~
non-oxidation atmosphere such as in a stream of N2 or -oth~r non-activated gases~ "
In the case of the raw material being an ammonium salt of a methylene type condensation product of an aromatic sulfonic acid,`a sulfurous acid and an "
ammonium root are eliminated in the principal range of 2~0 to 350C during the carbonization, when the raw material of about 50% by weight is lost. In order to _ 20 prevent the derogation of fibrous quality owing to a . _ . .
sudden elimination of volatile matters, it is favorable that thermal ascending is made at a gentle speed in the range of 250 to 350C or that a thermal retention time in the same thermal range is included in a thermal proqram for the carbonisation. The fiber may further be fired at a temperature of 2,000 to 3,000C to obtain a carbon fiber comprising graphite. In addition, its properties (e.g., tensile strength~ can further be improved by drawing the fiber during the firing operation.
Where a carbon material in the form of a molded article is to be produced by the process of the present invention, the cdntent of the condensation produ`ct in the raw mate * al composition for molding (i.e., the molding material) may vary according to the types of the condensation product, water-soluble polymeric compound and solvent. Rowever, it is generally i~ in the range of 20 to 90% by weight and preferably in the range of 40 to 80% by~weight.
The molded article can be carbonized under ~ `
substantially the same conditions as employed for the spun fiber.
In a preferred em~odiment of the present invention, a continuous process can be established ~`
which comprises sulfonating~the aromatic compound used _ 20 as the raw material, condensing it with the aid of ,~, formalin or the li~e while controlling the water content and pR of the r~action system, neutralizing the condensation product, removing any"insoluble matter ~ccording to the needr adjusting the viscosity of the . .
condensation product ~e.g., by controlling its water content) to prepare a spinning or molding material, ,'~.' . ': .
"'','',,.
"' .:
spinning or molding it, and then carbonizing the spun fiber or molded article to obtain a carbon material.
Moreover, better results can be obtained by adding the above-described water-soluble polymeric compound at the time of prep~ration of the spinning or molding material.
The properties`of carbon fibers produced by the process of the present invention will vary according to the type of the aromatic compound, or salt thereof, 1~ used in the spinning material, the diameter of the fiber, and the like. More specifically, the strength of the resulting fiber increases with a rise in carboniza-tion temperature. For example, the fi~er fired at 600C has a strength of 20 to 50 kg/mm2 and the fiber `
fired at 1,200C has a strength of 40 to 200 kg/mm2.
The carbon materials produced by the process of the present invention have a relatively }arge specific surface area because the elimination of sulfonic groups occurs in the carbonization step. Moreover, since 20 the ra~ material is sulfonated while it is in the low-molecular-weight state, the sulfonic groups are distributed evenly. Therefore, the carbon materials produced by the present invention are more homogeneous and have more excellent properties than those produced by conventional met~ods such as the treatment of polymers with sulfuric acid. These carbon materials, especially "
1 32~469 in fibrous fonm, can be used as fillers for various composite materials and as heat insulating materials.
Moreover, by further subjecting them to an activation treatment, they can also be used as adsorbent or separating materials, including molecular sieve carbon materials, activated carbon fibers and the like.
The activation ~reatment can be carried out in the same manner as for the preparation of ordinary activated carbon and the like. Specifically, the carbon materials of the present invention may be activated by suitable gases such as steam, air and C02 or by suitable i~ chemicals such as 3inc chloride or sulfuric acid. ~
The activation treatment may be carried out ` `
after the spun fiber or molded article has been carbonized, or while the spun ~iber or molded article is being carbonized.
In one embodiment of the activation treatment using steam as the activator, the spun fiber or molded `
article ~not carbonized) is heated at a temperature of 20 350C or above, preferably 450C or above, in an `
atmosphere of an inert gas and then treated with steam at a t~mperature of 700 to 900C for 10 to 120 minutes.
Where an activator (such as C02) involving no risk of dissolving the spun fiber or molded article is used, the spun fiber or molded article may be directly treated with steam at a temperature of 700 to 1,000C for lo to 180 minutes without heating at a lower temperature.
As a result of the above-described activation treatment, there is obtained an activated carbon mate-r al having a specific surface area of 500 to 2,500 ; m /g as measured by the N2 BET method.
According to th~ process of the present invention, carbon materials having excellent properties and useful in wide applications can be produced by much simpler operation, as compared with prior art processes.
Moreover, because of the ragular el~mination of sulfonic i groups, the carbon materials produced thereby have good ho geneity and high activity and, therefore, are of great industrial value.
The process of the present invention will be ~oru specifically explained wlth reference to the follo~ing ex~nples.
~xa~ple 1 _ 20 1,280 g of naphthalene having a purity of 9S~ ~as mixed with 1,050 g of 98% sulfuric acid and sulfonated at ~60C for 2 hours. Unreacted naphthalene and the water formed by the reaction were removed from the system by distillation under reduced pressure.
Then, 857 g of 35~ fonnalin was added and the resulting `
m~xture ~as reacted at 105C for 5 hours to obtain a - `
l 32446q methylene-linked condensation product of naphthalene-~-sulfonic acid. Furthermore, this condensation product was neutraliæed with aqueous ammonia and then filtered through No. 5 filter paper Imanufactured by Toyoroshi Kaisha, Ltd.). The filtrate was concentrated to obtain a spinning material in the form of a solution containing 34% by weight of water and having a viscosity of 100 centipoises at 85C. The~resulting salt of the conden-sation product had a number-average molecular weight of 4,300. This spinning material was dry-spun using a stainle~s steel spinneret having an orifice diameter of 0.1 mm.
The spun fiber was directly subjected to a carbonization step~ Specifically, the fiber was fired in a stream of N2 by raising the temperature from room temperature to 800C at a ratè of 10C/min. The ;
resulting carbon ~iber had a diameter of 12 ~m, a tensile strength of 65 kg/mm2, a specific surface area ;
of 250 m2/g a~ measured by thè C02 BET me~hod, and a specific surface area o~ 30 m2/g as measured by the N2 BET method. Moreover, when measured at 25C under 3 atmospheres, its equilibrium C02 adsorption was 188 ml/g and its equilibrium N~ adsorption was 25 ml/g.
Furthermore, the above fiber was activated by treatment with steam at 850C for 60 minutes. The resulting fiber had a specific surface area of },470 m2/g ~ ``
~ ',~~ ' .''. ' ~
.~
as measured by the CO2 BET method, and a specific sur-face area of 1,560 m2/g as measured by the N2 BET
method.
5 Example 2 ;` 1,700 g of creosote oil was mixed with 1,050 g of 98% sulfuric acid and`sulfonated at 160C for 2 hours. Unreacted oil and~the water formed by the reaction were removed from the sys~em by distillation.
Then, 857 g of a 35% aqueous solution of formalin was added and the resulting mixture was reacted at 105C for 5 hours to obtain a methylene-linked condensation product of aromatic sulfonic acids. This condensation product was mixed with 37 g of calcium hydroxide to convert the excess sulfuric acid to gypsum, and then centrifuged to re~ove it together with water-insoluble gel-like solid matter. ~fter centrifugation, the supernatant liquid was adjusted to a water content of 40~ by weight. Thus, spinning material A was 20 obtained in the form of a solution having a viscosity of 100 centipoises at 85C. On the other hand, spinning material B was prepared by taking a part of spinning solution A, neutralizing it with sodium hydroxide, purifying it again by filtration, and then adjusting the filtrate to a water content of 40% by weight. Spinning material A was spun using a platinum spinneret. The spun fiber was directly subjected to a carbonization 1 32446q step where it was fired in a stream of N2 by raising the temperature from room temperature to 1,200C at a rate of 10C/min. The resulting carbon fiber had a diameter of 15 ~m and a tensile strength of 52 kg/mm2.
spinning material B was spun using a stainless steel spinneret. The spun fiber was directly subiected to a carbonization step where it was fired in a stream of N2 by raising the temperature from room temperature to 800C at a rate of 10C/min and then to an activation s~ep by steam at a tempera~ure of 900C for 15 minutes. , -The resulting carbon fiber had a diameter of 12 ~m, a , i~ tensile strength of 30 kgfmm2, a specific surface ~'`
area of 720 m2~g as measured by the C02 BET method, and a specific surface area of 870 m /g as measured 15 by the N2 BET method. ~ , .
Example 3 1,280 g of naphthalene having a purity of 95% ~`
~as mixed ~ith 1,050 g of 983~ sulfuric acid and _ 20 sulfonated at 158C for 1 hour. Unreacted naphthalene and the water formed by the reaction were removed from ~he system by distàllation under reduced pressure. ,~
Howe3ver, 0.6% (based,on the charged amount~ of unreactëd naphthal3ene remained in the system. Then, 875 g of ' ''' 25 35~ formalin was added and the resulting mixture was ' ,- ' reacted at 105C for 5 'hours to obtain a methylene-linked ; ' , , , - , .. , : . . . ... . ~
condensation product of naphthalene-B-sulfonic acid This condensation product had a number-average molecular weight of 3 200 Furthermore the condensation product was neutralized with ammonia and then filtered through No SC filter paper (manufactured by Toyoroshi Raisha Ltd ) To the filtrate ~as add~d a specified amount of an aqueous solution of Poval PVA-217~ (manu-f~ctured by ~uraray Co ~Ltd ; polymerization degree 1 700-2,~00) Th~ filtr~te containing the ~ater-~olubl~ polym~ric compound ~a~ conc~ntr~ted to obtain a ~pinning matarial having a vi~co~ity of 20 poi~e~
i~ a~ ~a~ur~d at 85'C wit~ a Brookfi-ld typ~ vi~co~ ter T~ pinn~ng ~at~rial ~ dry-~pun at bout 60 C u~ing a ~tainlar~ ~t~ l ~pinn~ret having an ori~ica diametar of 0 2 no S~a ~pun f~ r ~nr dircctly ~ub~c~d to c rbo ~ ~tlo~l ~t p. ~cifical.ly, th~ fib-r ~ ~
pl ~ d ~ tr~n of N2 ~nd h ae ~ fro~ ro ~ t~pera-t~r~ t ~i r~t of 200-C~A on the av~r~ge D~r~ t ~ tioni procc-~, t~ fib r ~ held _ 20 ~t ~ C ~ ~ ~nut~ and at l,OOO-C for S minute~
Th pi~ t~ Of ~pinning m~it ri~l~ contain~ng variouJ ~ount of ~VA and ~o~e prop rti-- of th-carbon f~bor~ fo`~ di fro~ ~he~- pinning mat ri~ are ~boNn iA Tablc 1 .~,,~ ~.
.
0~^ __ O ~ ~
~ .~ .,1 ~ P.
S~ ~ ~ a tJ~ 1: ~ Cl~ ~ ~ ~ ~ t`~ _I N O N U~
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~I) .q x ~ a~
_ ~ Q O Q~ 3 ~:
s~ ~
o~q ~` ~ ~
_ co ~ ~ ~ ~ .~
Among carbon materials in such fibrous forms as generall~ called carbon fibers, molecular sieve `-`
carbon fibers or activated carbon fibers, carbon fibers are produced by spinning rayon, lignin, polyacrylonitrile _ ~herainafter referred to as PAN~, pitch or the like, 20 rendering the spun fiber infusible, carboni2ing it at `
a temperature of 1,000 to 1,600C,,or further graphitiz- ;
ing the resulting carbon fiber at a temperature of :~
2,000 to 3,000C. On the other hand, molecular sieve :~
. ~.
carbon fibers and activated carbon fibers are produced 25 either by spinning a raw material as described above, ` .
~ ` ' "
~ .''. . ':
:~ ...,, :...
l 32446q rendering the spun fiber infusible, and then activating it, or by rendering the spun fiber infusible, carbonizing it, and then activating the resulting carbon fiber.
Although these carbon materîals in fibrous form have excellent properties which are not possessed by other materials, they involve`several operational problems as described in~the f~llowing paragraphs (1) to ~3). Therefore, these carbon materials are high in price and still far from being widely used as common industrial materials~
(1) In order to provide industrially practicable spinnability, the spinning material must previously be freed of any for~ign matter by hiqh-precision filtration.
(2) Rayon and PAN are spun according to the wet or dry spinning te~hnique, which involves the cost of solvent recoYery. On the other hand, the spinning of lignin and pitch produces tar and mist, so that it is important to control the spinning atmosphere.
_ 20 (3) All of the fibers spun from the aforesaid raw ~.
materials require a treatment for rendering them - -infusible. Generally, this treatment is carried -out by air oxidation. In,this treatment, a long treating time, l~rge-capacity oxidizing equipment and the like are needed to prevent violent exothermic reaction, i.e., combustion. -`
:
In order to eliminate the time-consuming step of rendering the spun fiber infusible by air oxidation, there has been proposed a process in which fibrous polystyrene is soaked in sulfuric acid and then carbonized (Japanese Patent Publication No. 36085/'86). However, this process has the disadvantage that the sulfonation of polystyrene (i.e., the introduction of sulfonic groups into polystyrene) is not ~ffected uniformly throughout the entire fiber. That is, spots rendered infusible, spots made fragile due to excessive sul~onation, and spots not rendered infusible are formed in the fiber surfaces, resulting in a very inhomogeneous ~iber.
, ~
SU~NARY OF THE INVENTION
lS It is the primary ob~ect of the present in~ention to provide a process for producing carbon `
ma~erial~ by ~hich the abovè-described problems of the prior art can be solved and in which carbon materials ha~ng the form of fibers or molded articles (such as honeycQmbs) and useful as components for various composite materials and as adsorbent or separating materials can be produced by easy and simple operation.
In view of ~he above and other objects, the present inventors have made an intensive inveatigation and have found that the above-described problems can be solved by using a methylene type linkage-containing condensation product of an aromatic sulfonic acid or a salt thereof as the spinning or moldinq material. The present invention has been completed on the ~asis of this finding.
According to the present invention, there is provided a process for producing carbon materials which comprises the steps of p~eparing a raw material -composition comprising a methylen type linkage-containing condensation product of an aromatic sulfonic acid or a salt thereof and a solvent, the condensation product having been formed by means of a linkage of the formula -(CH2)n-Tx (CHR~m (1) where T is a benzene or nap~hthalene ring, R is a hydrogen atom, an alkyl group of 1 to i carbon atoms, or a ben~ene ring, and each of n, m and x is 0 or 1, but n and m should not be zero at the same time; spinning or molding the raw material composition; and carbonizing the spun fiber or molded article.
~ ~ .
DETAIL~D DESCRIPTI~N OF THE IN~ENTION
_ Specific examples of the aromatic sulfonic ~ -acid, or salt thereof, which is used in the present invention include naphthalenesulfon~c acid, anthracene-sulfonic acid, phenantbrenesulfonic acid, sulfonated . .
~ , . ' ~ . ~ ' . . ' products of polycyclic aromatic compound mixtures (such as creosote oil, anthracene oil , tar and pitch), toluenesulfonic acid, xylenesulfonic acid, sulfonated phenols and mixtures thereof, as well as salts of the foregoing. These aromatic sulfonic acids can be : obtained by sulfonàting the corresponding àromatic compounds according to an~ of vario~s well-known methods.
Although ~he cation constituting salts of the aromatic sulfonic acids can be Na~, K~, Ca~2, NH4~ and the like, 10 ammonium salts are preferred because of the ease with ~ ~`
~hich the spun fiber can be handled in the carbonization step. Moreover, preferred salts may vary according to the desired type of carbon material. That is, ammonium salts are preferred for the productàon of carbon -materials re~uirin~ strength. In order to produce porous adsorbent materials or separating materials, ` `
ammonium salts can be used satisfactorily, but sodium and calciu~ salts are more preferred.
Condensation product~ of the above-described `` 20 aromatic sulfonic acids or salts thereof can be prepared according to any of various well-known methods. However, it is common practice to condensate an aromatic sulfonic acid or a salt thereo~ with the aid of formalin, `
paraformaldehyde, hexamethy}enetetramine or other aldehyde. It is also possible to use a methylene type linkage-containing polymer (such as polystyrenesulfonic acid) obtained by polymerizing an aromatic sulfonic acid having a vinyl group. Although the linkage connect-ing molecules of the aromatic sulfonic acid may be any of the linkages within the scope of formula (1), the -CH2- linkage is especially preferred because ` methylene-linked condensation products are easy to prepare or obtain. And ~he linkage in a methylene type linkage-containing condensation product of an aromatic sulfonic acid or a salt thereof as said in the present invention, includes not only those which connect directly with an aromatic ring but also those which connect by means of side chains as in the case of a polystyrenesulfonic acid.~
Various types of condensation products can be obtained, depending on the type of aromatic compound us~d, the conditions of sulfonation and condensation reactions, and the like. Of course, these condensation pr~ducts may be used alone or in admixture of two or more, and may also be used in the form of polycondensation _ 20 products.
As an example of the methylene type linkage-containing condensation product of aromatic sulfonic acid, or salt th~reof, which is used in the process of the present invention, mention is made of a condensation product obtained by condensing ammonium naphthalene-~-sulfonate with the aid of formaldehyde. This condensation ' .:`
. ,"., ~; ;; .
1 32446q product is a mixture of monomer and various polymers having polymerization degrees of up to about 200, and has a number-average molecular weight of about 2,000 to 50,000. This condensation product is a solid at ordinary temperatures, sparingly soluble in organic solvents such as benzene,~toluene and acetone, and readily soluble in aqueous solvents. A 60~ ~w/w) aqueous solution thereof~has a viscosity of about 10 to 20,000 poisas at 60C and exhibits adequate `.
10 spinnability and moldability. When this condensation .
product is carbonized at a temperature of 800 to 1,000C, the yield of the resulting carbon material is .. ~: .... .
about 50% by weiqht~
The above-described condensation product is only one example of the condensation products useful in the process of the present invention, and it is to be understood that the range of the polymerization de~ree, or number-average molecular weight, of a : .
condensation product useful in the process of the present 20 invention depends on the type of the aromatic sulfonic acid, or salt thereof, constituting the condensation product. For example, a useful condensation product ~ :
of sulfonated creosote oil is a mixture of monomer and various polymers having polymerization degrees of ~.
25 up to about 40, and has a number-average mo~ecular ~:
weight of about 2,000 to about 5,000. A useful ~;
' :
~' ':' ' .
condensation product of phenanthrenesulfonic acid is a mixture of monomer and various polymers having polymerization degrees of up to about 30, and has a number-average molecular weight of about 2,500 to about 5,000.
T~e above-definèd condensation product or polymer of aromatic sulfonic acid or salt thereof is dissolved or dispersed i~p~a solvent to prepare a raw material composition. If necessary, the viscosity of this raw material composition is adjusted by suitable means such as dilution and concentration. Then, the ra~ material composition is spun into fibrous form or molded into any desired shape such as block, column, plate, film or honeycomb. Finally, the spun fiber or molded article is carbonised to obtain a carbon material.
In view of the properties of t~ë condensation product or polymer of aromatic sulfonic acid or salt thereof, the solvent used in the process of the present _ 20 invention is preferably selected from polar solvents `
including water, alcohols (such as methanol), aceto-nitrile and the like. Among others, it is most preferable to use water or an aqueous solvent comprising a mixture of water and a suitable water-soluble solvent.
Where a carbon material in fibrous ~orm is to be produced by the process of the present invention, it -g is undesirable that the aromatic sulfonic acid used as the raw material contains a high proportion of unsulfonated aromatic compounds, because they make -the resulting carbon fibers inhomogeneous and cause a reduction in strength. In such a case, the methylene type linkage-containing condensation products of unsulfonated aromatic cQ~pounds can be removed by .
using water as the solve~nt. That is, since the methylene-linked condensation products of unsulfonated aromatic compounds àre hardly soluble in water and, therefore, can be separated from the spinning solution .`
i~ according to suitable techniques such as filtration, .
centrifugation and dialysis. Moreover, the use of an agueous solvent is preferred from operational points `.`
of view, because the spinning atmosphere can be controlled easily.and there is no risk of ignition or explosion.
In the process of the present invention, the . .
spinnability and moldability of the raw material ` ;
composition can further be improved by adding a water~
soluble polymeric compound, as a spinning or molding aid, to the raw material composition in an amount of :
0.02 to 20 parts by weight per 100 parts by weight .:
of the solid constituent of the raw material composition.
25 The water-soluble polymeric compound used in the present~ .
invention can be any of various polymeric compounds ~.
that are soluble or colloidally dispersible in water and aqueous solvents. Especially preferred are poly-alkylene oxid~ compounds such as condensation products of ethylene oxide, propylene oxide, etc., and condensa-tion products obtained by ~he reaction of these compounds : with various alcohols, fatty acids, alkylamines andalkylphenols; polyvinyl cQmpounds such as polyvinyl alcohol and polyvinyl py~rolidone; polyacrylic compounds such as polyacrylic aci~, polyacrylamide and acrylic acid-acrylamide copolymer; and the like. Among the methylene-linked condensation products of aromatic sulfonic acids, or salts thereof, which can be used as the raw material in the process of the present invention, those having high solubility in water ~such as poly-styrenesulfonic acid) can also be used as the water-so}uble polymeric compound. The addition of such a ~ater-soluble polymeric ~ompound is effective in ~`
accelerating the spinning speed, making it easy to ` `
handle the spun fiber or molded article prior to 20 carbonization, and increasing the strength of the resulting carbon fiber or molded product. If the amount of water-soluble polymeric compound added is less than 0.02 part by weight, a satisfactory effect cannot be obtained. If it is greater than 20 parts by weight, the fiber or the }ike is liable to fusion during the heating operation for carbonization. This is undesirable because a separate step of rendering it infusible is required.
As described above, the methylene type linkage-containing condensation product of aromatic sulfonic acid or salt thereof, which is used in the process of : th`e present invention, can be spun or molded and then carbonized to produce ca~bon materials in fibrous form and in various other forms. However, on the basis of `~
the feature that the aforesaid condensation product can be carbonized without being rendered infusible, the process of the present il~vention is particularly suitable for the production of caxbon materials in fibrous form.
The content of the condensation product in the raw material composition for spinning ~i.e., the 15 spinning material) may vary according to the types of :
the condensation product~ water-soluble polymeric co~pound and solvent. ~owever, it is qenerally in the ` `
r~nge of 20 to 80~ by weight and preferably in the range o~ 40 to ?0~ by weight.
_ 20 In the spinning material liquid there are sometimes produced impurities from the raw materials or derivative substances, whether in solid or gel, resulted from reaction by-products among the raw matèrials. -The removal of such i~purities or substances is effective in gaining a high-spinnability or an improved q~ality of carbon materials in fibrous form. Though it can be made outside a spinning machine, the removal can be far effectively carried out by placing a sintered metal filter, a sintered metal fibrous filter, a sintered metal wire netting filter or a pack filter of various metal fillers upon a spinneret.
The spinning temperature may vary according to the composition of t~è spinning material, the desired shape of fiber, and the like. However, where water is used as the solvent, the spinning temperature is preferably in the range of 20 to 100C. The fiber emerging from the spinnerlet is drawn out by means of a wind-up roll, godet rolls, an air sucker or the like, is wound up or is accumulate~ in a receiver after having been dried within a barrel dryer equipped under the spi~neret, preferably in a heated-air stream flowing in parallel to the progress of the ~iber. A draft ratio ~i.e., the spinneret's di~meter/the spun fiber's diameter) where thè fiber is drawn out, can be 100 to 2; however, a preferable range of it is 10 to 5. A 20 fiber ~ith a big surface can be also produced by apply-ing a spinneret of irregular form in order to ease the drying of the fiber and enhance the fibrous strength. -Although the diameter of the spun fiber may be determined aribitrarily, it is preferably in the range of 2 to 100 , .
25 ~m and more preferably in the range of 8 to 20 ~m. `
There is a possibility that the spun fiber .
might absorb humidity and melt into another one because of its hygroscopicity if it is left for a long time in the open air. Accordingly, it is favorable soon to send the spun ~iber to the carbonization process or to stock it in the dry air when necessary.
According to the process of the present invention, the spun fiber can be carbonized without being rendered infusible~ In the carbonization process the spun fiber is fired by heating at a thermal ascending speed of 1 to 2,000C/min., preferably 10 to 500C/min., up to a temperature of 500 to 2,000C, but under a -~
non-oxidation atmosphere such as in a stream of N2 or -oth~r non-activated gases~ "
In the case of the raw material being an ammonium salt of a methylene type condensation product of an aromatic sulfonic acid,`a sulfurous acid and an "
ammonium root are eliminated in the principal range of 2~0 to 350C during the carbonization, when the raw material of about 50% by weight is lost. In order to _ 20 prevent the derogation of fibrous quality owing to a . _ . .
sudden elimination of volatile matters, it is favorable that thermal ascending is made at a gentle speed in the range of 250 to 350C or that a thermal retention time in the same thermal range is included in a thermal proqram for the carbonisation. The fiber may further be fired at a temperature of 2,000 to 3,000C to obtain a carbon fiber comprising graphite. In addition, its properties (e.g., tensile strength~ can further be improved by drawing the fiber during the firing operation.
Where a carbon material in the form of a molded article is to be produced by the process of the present invention, the cdntent of the condensation produ`ct in the raw mate * al composition for molding (i.e., the molding material) may vary according to the types of the condensation product, water-soluble polymeric compound and solvent. Rowever, it is generally i~ in the range of 20 to 90% by weight and preferably in the range of 40 to 80% by~weight.
The molded article can be carbonized under ~ `
substantially the same conditions as employed for the spun fiber.
In a preferred em~odiment of the present invention, a continuous process can be established ~`
which comprises sulfonating~the aromatic compound used _ 20 as the raw material, condensing it with the aid of ,~, formalin or the li~e while controlling the water content and pR of the r~action system, neutralizing the condensation product, removing any"insoluble matter ~ccording to the needr adjusting the viscosity of the . .
condensation product ~e.g., by controlling its water content) to prepare a spinning or molding material, ,'~.' . ': .
"'','',,.
"' .:
spinning or molding it, and then carbonizing the spun fiber or molded article to obtain a carbon material.
Moreover, better results can be obtained by adding the above-described water-soluble polymeric compound at the time of prep~ration of the spinning or molding material.
The properties`of carbon fibers produced by the process of the present invention will vary according to the type of the aromatic compound, or salt thereof, 1~ used in the spinning material, the diameter of the fiber, and the like. More specifically, the strength of the resulting fiber increases with a rise in carboniza-tion temperature. For example, the fi~er fired at 600C has a strength of 20 to 50 kg/mm2 and the fiber `
fired at 1,200C has a strength of 40 to 200 kg/mm2.
The carbon materials produced by the process of the present invention have a relatively }arge specific surface area because the elimination of sulfonic groups occurs in the carbonization step. Moreover, since 20 the ra~ material is sulfonated while it is in the low-molecular-weight state, the sulfonic groups are distributed evenly. Therefore, the carbon materials produced by the present invention are more homogeneous and have more excellent properties than those produced by conventional met~ods such as the treatment of polymers with sulfuric acid. These carbon materials, especially "
1 32~469 in fibrous fonm, can be used as fillers for various composite materials and as heat insulating materials.
Moreover, by further subjecting them to an activation treatment, they can also be used as adsorbent or separating materials, including molecular sieve carbon materials, activated carbon fibers and the like.
The activation ~reatment can be carried out in the same manner as for the preparation of ordinary activated carbon and the like. Specifically, the carbon materials of the present invention may be activated by suitable gases such as steam, air and C02 or by suitable i~ chemicals such as 3inc chloride or sulfuric acid. ~
The activation treatment may be carried out ` `
after the spun fiber or molded article has been carbonized, or while the spun ~iber or molded article is being carbonized.
In one embodiment of the activation treatment using steam as the activator, the spun fiber or molded `
article ~not carbonized) is heated at a temperature of 20 350C or above, preferably 450C or above, in an `
atmosphere of an inert gas and then treated with steam at a t~mperature of 700 to 900C for 10 to 120 minutes.
Where an activator (such as C02) involving no risk of dissolving the spun fiber or molded article is used, the spun fiber or molded article may be directly treated with steam at a temperature of 700 to 1,000C for lo to 180 minutes without heating at a lower temperature.
As a result of the above-described activation treatment, there is obtained an activated carbon mate-r al having a specific surface area of 500 to 2,500 ; m /g as measured by the N2 BET method.
According to th~ process of the present invention, carbon materials having excellent properties and useful in wide applications can be produced by much simpler operation, as compared with prior art processes.
Moreover, because of the ragular el~mination of sulfonic i groups, the carbon materials produced thereby have good ho geneity and high activity and, therefore, are of great industrial value.
The process of the present invention will be ~oru specifically explained wlth reference to the follo~ing ex~nples.
~xa~ple 1 _ 20 1,280 g of naphthalene having a purity of 9S~ ~as mixed with 1,050 g of 98% sulfuric acid and sulfonated at ~60C for 2 hours. Unreacted naphthalene and the water formed by the reaction were removed from the system by distillation under reduced pressure.
Then, 857 g of 35~ fonnalin was added and the resulting `
m~xture ~as reacted at 105C for 5 hours to obtain a - `
l 32446q methylene-linked condensation product of naphthalene-~-sulfonic acid. Furthermore, this condensation product was neutraliæed with aqueous ammonia and then filtered through No. 5 filter paper Imanufactured by Toyoroshi Kaisha, Ltd.). The filtrate was concentrated to obtain a spinning material in the form of a solution containing 34% by weight of water and having a viscosity of 100 centipoises at 85C. The~resulting salt of the conden-sation product had a number-average molecular weight of 4,300. This spinning material was dry-spun using a stainle~s steel spinneret having an orifice diameter of 0.1 mm.
The spun fiber was directly subjected to a carbonization step~ Specifically, the fiber was fired in a stream of N2 by raising the temperature from room temperature to 800C at a ratè of 10C/min. The ;
resulting carbon ~iber had a diameter of 12 ~m, a tensile strength of 65 kg/mm2, a specific surface area ;
of 250 m2/g a~ measured by thè C02 BET me~hod, and a specific surface area o~ 30 m2/g as measured by the N2 BET method. Moreover, when measured at 25C under 3 atmospheres, its equilibrium C02 adsorption was 188 ml/g and its equilibrium N~ adsorption was 25 ml/g.
Furthermore, the above fiber was activated by treatment with steam at 850C for 60 minutes. The resulting fiber had a specific surface area of },470 m2/g ~ ``
~ ',~~ ' .''. ' ~
.~
as measured by the CO2 BET method, and a specific sur-face area of 1,560 m2/g as measured by the N2 BET
method.
5 Example 2 ;` 1,700 g of creosote oil was mixed with 1,050 g of 98% sulfuric acid and`sulfonated at 160C for 2 hours. Unreacted oil and~the water formed by the reaction were removed from the sys~em by distillation.
Then, 857 g of a 35% aqueous solution of formalin was added and the resulting mixture was reacted at 105C for 5 hours to obtain a methylene-linked condensation product of aromatic sulfonic acids. This condensation product was mixed with 37 g of calcium hydroxide to convert the excess sulfuric acid to gypsum, and then centrifuged to re~ove it together with water-insoluble gel-like solid matter. ~fter centrifugation, the supernatant liquid was adjusted to a water content of 40~ by weight. Thus, spinning material A was 20 obtained in the form of a solution having a viscosity of 100 centipoises at 85C. On the other hand, spinning material B was prepared by taking a part of spinning solution A, neutralizing it with sodium hydroxide, purifying it again by filtration, and then adjusting the filtrate to a water content of 40% by weight. Spinning material A was spun using a platinum spinneret. The spun fiber was directly subjected to a carbonization 1 32446q step where it was fired in a stream of N2 by raising the temperature from room temperature to 1,200C at a rate of 10C/min. The resulting carbon fiber had a diameter of 15 ~m and a tensile strength of 52 kg/mm2.
spinning material B was spun using a stainless steel spinneret. The spun fiber was directly subiected to a carbonization step where it was fired in a stream of N2 by raising the temperature from room temperature to 800C at a rate of 10C/min and then to an activation s~ep by steam at a tempera~ure of 900C for 15 minutes. , -The resulting carbon fiber had a diameter of 12 ~m, a , i~ tensile strength of 30 kgfmm2, a specific surface ~'`
area of 720 m2~g as measured by the C02 BET method, and a specific surface area of 870 m /g as measured 15 by the N2 BET method. ~ , .
Example 3 1,280 g of naphthalene having a purity of 95% ~`
~as mixed ~ith 1,050 g of 983~ sulfuric acid and _ 20 sulfonated at 158C for 1 hour. Unreacted naphthalene and the water formed by the reaction were removed from ~he system by distàllation under reduced pressure. ,~
Howe3ver, 0.6% (based,on the charged amount~ of unreactëd naphthal3ene remained in the system. Then, 875 g of ' ''' 25 35~ formalin was added and the resulting mixture was ' ,- ' reacted at 105C for 5 'hours to obtain a methylene-linked ; ' , , , - , .. , : . . . ... . ~
condensation product of naphthalene-B-sulfonic acid This condensation product had a number-average molecular weight of 3 200 Furthermore the condensation product was neutralized with ammonia and then filtered through No SC filter paper (manufactured by Toyoroshi Raisha Ltd ) To the filtrate ~as add~d a specified amount of an aqueous solution of Poval PVA-217~ (manu-f~ctured by ~uraray Co ~Ltd ; polymerization degree 1 700-2,~00) Th~ filtr~te containing the ~ater-~olubl~ polym~ric compound ~a~ conc~ntr~ted to obtain a ~pinning matarial having a vi~co~ity of 20 poi~e~
i~ a~ ~a~ur~d at 85'C wit~ a Brookfi-ld typ~ vi~co~ ter T~ pinn~ng ~at~rial ~ dry-~pun at bout 60 C u~ing a ~tainlar~ ~t~ l ~pinn~ret having an ori~ica diametar of 0 2 no S~a ~pun f~ r ~nr dircctly ~ub~c~d to c rbo ~ ~tlo~l ~t p. ~cifical.ly, th~ fib-r ~ ~
pl ~ d ~ tr~n of N2 ~nd h ae ~ fro~ ro ~ t~pera-t~r~ t ~i r~t of 200-C~A on the av~r~ge D~r~ t ~ tioni procc-~, t~ fib r ~ held _ 20 ~t ~ C ~ ~ ~nut~ and at l,OOO-C for S minute~
Th pi~ t~ Of ~pinning m~it ri~l~ contain~ng variouJ ~ount of ~VA and ~o~e prop rti-- of th-carbon f~bor~ fo`~ di fro~ ~he~- pinning mat ri~ are ~boNn iA Tablc 1 .~,,~ ~.
.
0~^ __ O ~ ~
~ .~ .,1 ~ P.
S~ ~ ~ a tJ~ 1: ~ Cl~ ~ ~ ~ ~ t`~ _I N O N U~
O
~I) .q x ~ a~
_ ~ Q O Q~ 3 ~:
s~ ~
o~q ~` ~ ~
_ co ~ ~ ~ ~ .~
3 ~iP 3 t:~ ~ 1~ t~
~` g -, ,~
~1 c~ .. o 'u~
0~ O O O O O O O O O O ~ U ~ `rI
~-1 ~ O ~1 ~D O ~ r ~ o .C
E~ ~ ~ ~ O
~ ~ ~ - ~ ~ o~ :
~-- ~ ~ u ~
~ 8 ~ a co ~ ~ o o ~ ~ o ~ ~
- ~o ~ ~ ~ ~ ,p ,~,. .
. ~ ~s ~
O ~ ~ ~o ~ ~ r co o ~ O O O` O O ~ ~ a 3 ~
~ --`~ ~
The carbon fiber having a PVA content of 0.8%
was activated by treatment with steam at 850C for 60 minutes. The resulting fiber had a specific surface area of 1,400 m /g as measured by the C02 BET method, and a specific surface area of 1,520 m2/g as measured by the N2 BET mèthod. .
Example 4 ~
2,000 q o~ creo~o~e oil wa~ mixed with 10 1,050 g of 98~ ~ulfuric acid and sulfonated at 158C
for 1 hour. unreacted oil and th~ ~at~r form~d by th ; r~act$on ~or~ romov~d fro~ th ~y~t~u ~y di~till~tion.
Then, 357 g Of a 35~ aqul~Ou~ ~olution of formal$n ~- add~d and the~r~ulting ~xture ~ reacted at 105C
for 5 bour~ to obta$n a ~a~hyl-na~ cd cond n~ation product of ro~-tic ~u~fonic ~Cid~ iC~ b~d ~ nu~b~r ~v~rag~ nol~cular ~oig~t of 5600 Thl~ condan-ation ~ ~ ~it~ 37 g of calc~un ~ydroxld~ to cc ~ud~ o ulfuric ~cid to gy~-u~, and tbcn _ 20 ~ r no~a ny i~ olubl~ ol~d ~ tt r Tb~
filtr~t~ ~q~ ~ utr~ d ~ith ~-oon~ nd divid~d into fiva ~qual p~rt~ To four of th -o part- ~ro ~dd~d pocl~ d mo~nt~ of aqu ou- olutio~- of poly~tyr-n--Jul~oo~c ~o~d Jodiu~ ~-lt (P8-100, ~anuf~ctur~d by 25 $o oh Co , Ltd s avar~g~ mol~cular ~ight 800,000-1,200,000), polyacrylic acid 80dium salt (Aqualic MP-30~, 1 32446q manufactured by Japan Catalytic Chemical Industry Co , Ltd ; average molecular weight 40,000), polyacrylamide (Hopelon A-lo~, manufactured by Mitsui-Toatsu Chemicals Inc.; average molecular weight 600,000-700,000) and polye~hylene glycol tPEO-3, manufactured by Seitetsu Xagaku Co , Ltd average~molecular weight 600,000-1,100,000), re~pectively` T~ese liquid~ were filtered again through No 5C fil~er paper (manufactured by Toyoroshi Kai~ha, Ltd ) and then concan~rated to obt~in five spinning material~ having a vi~co~ity of 100 poises a~ mea~ured at 65 C ~it~ a Broo~field typo vi~comct r ~ch of th~s~ ~pinning mat-rlal~
dry-~pun u~ing a ~pinn~r~t h~v~ng an orific- dia~etor of 0 2 m~ Tho ~pun fiber ~a~ directly ~ub~oct~d to a c~rbcni~ation st p Specifically, thc fib~r plac~d in a ~tr a~ of N2 nd ~a~t-d fro~ roo~ t ~p ra- `
turc ~o l,OOO'C at a rat~ o~ 200 CJ~n on th av-r~g- ` `
Dur~ tbl~ ation proc~-, tha f~b r ~a~ hcld ~t ~O~C ~or ~ n~nute~ and at l,OOO C for S minuta~
_ 20 ~b~ J;dnrabl~t~ of t~a five ~pinnlng ~at rial~ ~nd ~o~ prop~rt~ ~ of tha carbon fibar- form d fro~ tha~a ~pinning ~at rial- ~re ~ho~n ~n Tabla 2 :, ' ;' ~
`''''''.
s CP
o~ ~
o ~ ~ o co _l R X ~ l:~ X
U~ U ~ _l .` ~U~ ` ." ~ O
o.q ~ ~ o S~ ~ U~ ~ O
O -` ~ .~
a ~ ~ ~ .
~ ~o ~o '`
P.~ ~ ~ .
~ ~ O O O O O ~ ~ .
u~ ~ ~
'~1~ ~--` ~D ~ ~ I` (~ D V
J~l ~ o a~ _l ~ 1~
3 P.
~0~ ~ 0 0~
^ ~ oo co 3`
,~ o _i _i o Cs~
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8 , ~ ~ .
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q ~ o ~ ~ ~ `
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~ P~ P Z ~ .
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0~ O O O O O O O O O O ~ U ~ `rI
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E~ ~ ~ ~ O
~ ~ ~ - ~ ~ o~ :
~-- ~ ~ u ~
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- ~o ~ ~ ~ ~ ,p ,~,. .
. ~ ~s ~
O ~ ~ ~o ~ ~ r co o ~ O O O` O O ~ ~ a 3 ~
~ --`~ ~
The carbon fiber having a PVA content of 0.8%
was activated by treatment with steam at 850C for 60 minutes. The resulting fiber had a specific surface area of 1,400 m /g as measured by the C02 BET method, and a specific surface area of 1,520 m2/g as measured by the N2 BET mèthod. .
Example 4 ~
2,000 q o~ creo~o~e oil wa~ mixed with 10 1,050 g of 98~ ~ulfuric acid and sulfonated at 158C
for 1 hour. unreacted oil and th~ ~at~r form~d by th ; r~act$on ~or~ romov~d fro~ th ~y~t~u ~y di~till~tion.
Then, 357 g Of a 35~ aqul~Ou~ ~olution of formal$n ~- add~d and the~r~ulting ~xture ~ reacted at 105C
for 5 bour~ to obta$n a ~a~hyl-na~ cd cond n~ation product of ro~-tic ~u~fonic ~Cid~ iC~ b~d ~ nu~b~r ~v~rag~ nol~cular ~oig~t of 5600 Thl~ condan-ation ~ ~ ~it~ 37 g of calc~un ~ydroxld~ to cc ~ud~ o ulfuric ~cid to gy~-u~, and tbcn _ 20 ~ r no~a ny i~ olubl~ ol~d ~ tt r Tb~
filtr~t~ ~q~ ~ utr~ d ~ith ~-oon~ nd divid~d into fiva ~qual p~rt~ To four of th -o part- ~ro ~dd~d pocl~ d mo~nt~ of aqu ou- olutio~- of poly~tyr-n--Jul~oo~c ~o~d Jodiu~ ~-lt (P8-100, ~anuf~ctur~d by 25 $o oh Co , Ltd s avar~g~ mol~cular ~ight 800,000-1,200,000), polyacrylic acid 80dium salt (Aqualic MP-30~, 1 32446q manufactured by Japan Catalytic Chemical Industry Co , Ltd ; average molecular weight 40,000), polyacrylamide (Hopelon A-lo~, manufactured by Mitsui-Toatsu Chemicals Inc.; average molecular weight 600,000-700,000) and polye~hylene glycol tPEO-3, manufactured by Seitetsu Xagaku Co , Ltd average~molecular weight 600,000-1,100,000), re~pectively` T~ese liquid~ were filtered again through No 5C fil~er paper (manufactured by Toyoroshi Kai~ha, Ltd ) and then concan~rated to obt~in five spinning material~ having a vi~co~ity of 100 poises a~ mea~ured at 65 C ~it~ a Broo~field typo vi~comct r ~ch of th~s~ ~pinning mat-rlal~
dry-~pun u~ing a ~pinn~r~t h~v~ng an orific- dia~etor of 0 2 m~ Tho ~pun fiber ~a~ directly ~ub~oct~d to a c~rbcni~ation st p Specifically, thc fib~r plac~d in a ~tr a~ of N2 nd ~a~t-d fro~ roo~ t ~p ra- `
turc ~o l,OOO'C at a rat~ o~ 200 CJ~n on th av-r~g- ` `
Dur~ tbl~ ation proc~-, tha f~b r ~a~ hcld ~t ~O~C ~or ~ n~nute~ and at l,OOO C for S minuta~
_ 20 ~b~ J;dnrabl~t~ of t~a five ~pinnlng ~at rial~ ~nd ~o~ prop~rt~ ~ of tha carbon fibar- form d fro~ tha~a ~pinning ~at rial- ~re ~ho~n ~n Tabla 2 :, ' ;' ~
`''''''.
s CP
o~ ~
o ~ ~ o co _l R X ~ l:~ X
U~ U ~ _l .` ~U~ ` ." ~ O
o.q ~ ~ o S~ ~ U~ ~ O
O -` ~ .~
a ~ ~ ~ .
~ ~o ~o '`
P.~ ~ ~ .
~ ~ O O O O O ~ ~ .
u~ ~ ~
'~1~ ~--` ~D ~ ~ I` (~ D V
J~l ~ o a~ _l ~ 1~
3 P.
~0~ ~ 0 0~
^ ~ oo co 3`
,~ o _i _i o Cs~
_ ~ t~ o O ~ .
8 , ~ ~ .
o,~t. ~ ~ .
O
q ~ o ~ ~ ~ `
~, ~
o o ~, o o o o o _ . .
~ P~ P Z ~ .
Claims (15)
1. A process for producing carbon materials which comprises the steps of preparing a raw material composition comprising a methylene type linkage-containing condensation product of an aromatic sulfonic acid or a salt thereof and a solvent, the condensation product having been formed by means of a linkage of the formula -(CH2)n-Tx-(CHR)m- (1) where T is a benzene or naphthalene ring, R is a hydrogen atom, an alkyl group of 1 to 4 carbon atoms, or a benzene ring, and each of n, m and x is 0 or 1, but n and m should not be zero at the same time;
spinning or molding the raw material composition; and carbonizing the spun fiber or molded article.
spinning or molding the raw material composition; and carbonizing the spun fiber or molded article.
2. A process for producing carbon materials as claimed in claim 1 wherein the linkage of formula (1) is -CH2-.
3. A process for producing carbon materials as claimed in claim 1 wherein, prior to the spinning or molding step, a water-soluble polymeric compound is added to the raw material composition in an amount of 0.02 to 20 parts by weight per 100 parts by weight of the solid constituent of the raw material composi-tion.
4. A process for producing carbon materials as claimed in claim 2 wherein, prior to the spinning or molding step, a water-soluble polymeric compound is added to the raw material composition in an amount of 0.02 to 20 parts by weight per 100 parts by weight of the solid constituent of the raw material composition
5. A process for producing carbon materials as claimed in claim 1 wherein the product resulting from the carbonization step is further subjected to an activation treatment.
6. A process for producing carbon materials as claimed in claim 2 wherein the product resulting from the carbonization step is further subjected to an activation treatment.
7. A process for producing carbon materials as claimed in claim 3 wherein the product resulting from the carbonization step is further subjected to an activation treatment.
8. A process for producing carbon materials as claimed in claim 1 wherein the raw material composition is spun to obtain a carbon material in fibrous form.
9. A process for producing carbon materials as claimed in claim 2 wherein the raw material composition is spun to obtain a carbon material in fibrous form.
10. A process for producing carbon materials as claimed in claim 3 wherein the raw material composition is spun to obtain a carbon material in fibrous form.
11. A process for producing carbon materials as claimed in claim 4 wherein the raw material composition is spun to obtain a carbon material in fibrous form.
12. A process for producing carbon materials as claimed in claim 1 wherein the raw material composition is molded to obtain a carbon material in the form of a molded article.
13. A process for producing carbon materials as claimed in claim 2 wherein the raw material composition is molded to obtain a carbon material in the form of a molded article.
14. A process for producing carbon materials as claimed in claim 3 wherein the raw material composition is molded to obtain a carbon material in the form of a molded article.
15. A process for producing carbon materials as claimed in claim 4 wherein the raw material composition is molded to obtain a carbon material in the form of a molded article.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP206476/1987 | 1987-08-21 | ||
| JP20647687 | 1987-08-21 | ||
| JP63053802A JPH01132832A (en) | 1987-08-21 | 1988-03-09 | Method for producing carbon material |
| JP053802/1988 | 1988-03-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1324469C true CA1324469C (en) | 1993-11-23 |
Family
ID=26394517
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 574485 Expired - Fee Related CA1324469C (en) | 1987-08-21 | 1988-08-11 | Process for producing carbon materials |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0304010B1 (en) |
| JP (1) | JPH01132832A (en) |
| CA (1) | CA1324469C (en) |
| DE (1) | DE3888260T2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2857169B2 (en) * | 1989-05-22 | 1999-02-10 | 三井鉱山株式会社 | Sulfone group-containing heat-resistant polymer material and method for producing the same |
| US9920456B2 (en) | 2010-10-13 | 2018-03-20 | Mitsubishi Chemical Corporation | Carbon-fiber-precursor fiber bundle, carbon fiber bundle, and uses thereof |
| ES2610777T3 (en) | 2011-07-22 | 2017-05-03 | Mitsubishi Rayon Co., Ltd. | Copolymer based on polyacrylonitrile, precursor fiber based on polyacrylonitrile for carbon fiber, carbon fiber beams, fire resistant fiber bundle production process and carbon fiber beam production process |
| ES2610219T3 (en) * | 2012-07-12 | 2017-04-26 | Dow Global Technologies Llc | Processes for the preparation of carbon fibers by using sulfur trioxide in a halogenated solvent |
| JP6604118B2 (en) * | 2015-09-29 | 2019-11-13 | 日本製紙株式会社 | Method for producing carbon fiber sheet |
| JP6657712B2 (en) * | 2015-09-29 | 2020-03-04 | 日本製紙株式会社 | Method for producing carbon fiber and carbon fiber sheet |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE757620A (en) * | 1969-10-17 | 1971-04-16 | Bayer Ag | CARBON FIBER PREPARATION PROCESS |
| JPS5263209A (en) * | 1975-11-20 | 1977-05-25 | Hitachi Chemical Co Ltd | Manufacture of carbon bodies |
-
1988
- 1988-03-09 JP JP63053802A patent/JPH01132832A/en active Granted
- 1988-08-11 CA CA 574485 patent/CA1324469C/en not_active Expired - Fee Related
- 1988-08-16 DE DE19883888260 patent/DE3888260T2/en not_active Expired - Fee Related
- 1988-08-16 EP EP88113265A patent/EP0304010B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0304010A3 (en) | 1990-02-28 |
| JPH01132832A (en) | 1989-05-25 |
| EP0304010A2 (en) | 1989-02-22 |
| EP0304010B1 (en) | 1994-03-09 |
| DE3888260T2 (en) | 1994-09-29 |
| JPH0440452B2 (en) | 1992-07-03 |
| DE3888260D1 (en) | 1994-04-14 |
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