US3661616A - Process for carbonizing cellulose fiber or the products thereof - Google Patents

Process for carbonizing cellulose fiber or the products thereof Download PDF

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US3661616A
US3661616A US869196A US3661616DA US3661616A US 3661616 A US3661616 A US 3661616A US 869196 A US869196 A US 869196A US 3661616D A US3661616D A US 3661616DA US 3661616 A US3661616 A US 3661616A
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ammonium
treated
heat
strength
cloth
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Kazuo Miyamichi
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NOTTO BOSEKI CO Ltd
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NOTTO BOSEKI CO Ltd
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    • 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
    • D01F9/16—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from products of vegetable origin or derivatives thereof, e.g. from cellulose acetate

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  • ABSTRACT Cellulose fiber or the product thereof is treated with a strength increasing agent selected from the group consisting of (A) at least one compound selected from ammonium sulfite, ammonium bisulfite, ammonium bisulfate, or ammonium thiosulfate; (B) a mixture of at least one compound selected from ammonium sulfate, ammonium bisulfate, ammonium sulfite, ammonium bisulfite, ammonium thiosulfate, ammonium sulfate, or ammonium imidosulfonate with at least one organic nitrogen base; and (C) a mixture of an organic nitrogen base and an acid selected from sulfuric acid, sulfurous acid or sulfamic acid.
  • A at least one compound selected from ammonium sulfite, ammonium bisulfite, ammonium bisulfate, or ammonium thiosulfate
  • B a mixture of at least one compound selected from ammonium sul
  • the present invention relates to a process for producing excellent carbonized fiber or the product thereof by treating cellulose fiber or the product thereof with a specific strength increasing agent or a treating agent prepared by adding a flame resistance improving agent to said strength increasing agent and thereafter heat-treating the thus treated cellulose fiber or the product thereof.
  • the present invention concerns a process for carbonizing cellulose fiber or the product thereof characterized by treating cellulose fiber or the product thereof with a strength increasing agent comprising a specific compound or mixture mentioned below or with a treating agent obtained by adding a flame resistance improving agent to said strength increasing agent, thereafter carbonizing said cellulose fiber or product thereof by the heat treatment at a temperature of 200 to 350C. in an oxidative atmosphere and subsequently at a temperature of up to about l,000C. in an inert atmosphere and further if necessary, carbonizing or graphitizing the thus heat-treated fiber or product thereof by the heat treatment at a temperature of about 1,000C. or higher in an inert atmosphere.
  • a process for producing carbon fiber or graphite filament using cellulose fiber as a starting material has been known for a long time.
  • W.R. Whitrey showed in US. Pat. No. 916,905 (1909) a process for graphitizing carbon fiber by the heat treatment at a temperature of 2,300C. or higher.
  • British Pat. No. 1,025,499 (1964) employs the heating within a temperature of from 150 to 540C. at a heating rate of 10 to 30C./8 to 30 hours. Thus, this process requires 3 to 50 days for elevating the temperature up to 540C.
  • Japanese Pat. Publication No. l3,l l3/6l employs the heating to 400C. at a heating rate of 10 to 50C./hr. and thereafter the heating to 900C. at a heating rate of lC./hr. or less.
  • the present invention is to provide a new process which improves the above-mentioned conventional processes in the production of carbon-like fiber, carbon fiber, graphite fiber or products thereoffrom cellulose fiber or products thereof.
  • the object of the present invention is to provide a new treating agent or strength increasing agent which prevents the deterioration of cellulose due to the pyrolysis in the heat treatment of cellulose fiber or products thereof.
  • Another object of the present invention is to provide a process for preparing highly reinforced flexible carbon-like fiber, carbon fiber, graphite fiber or products thereof by treating cellulose fiber or products thereof with the above-mentioned strength increasing agent in the heating treatment of cellulose fiber or products thereof.
  • Another object of the present invention is to provide a process for highly increasing the strength of the heat-treated fiber or the products thereof in the heat treatment at a temperature of 200 to 500 C. at which the deterioration of cellulose is particularly remarkable and in the heat treatment at further higher temperatures.
  • Another object of the present invention is to provide an industrially extremely advantageous process which enables the heat treatment of high heating rate in the heat treatment of cellulose fiber or the products thereof.
  • the present invention requires the treatment with a specific compound or mixture which is called a strength increasing agent.
  • the strength increasing agent herein includes the following compounds and mixtures:
  • the nitrogen-containing base includes urea, urea derivatives, thiourea, thiourea derivatives and amines such a urea (CO[NH thiourea (CS[NH 21 guanidine (NI-I:C[NH dicyandiamide (NI-I C:NH NH CN), dicyandiamidine (NI-I C: NI-I NH CO NI-I triethylamine [C I-I N), triethanolamine ([CH CH OH] N),
  • the ammonium salt of paragraph (I) may be a mixture of two or more members thereof
  • the strength increasing agent of paragraph (2) may be a mixture of one member of ammonium salts and two or more members of nitrogen-com taining bases or a mixture of two or more members of ammonium salts and one or more members of nitrogen-containing bases.
  • the strength increasing agent of paragraph (3) may be prepared by adding two or more members of nitrogen-containing bases to one member of acids or by adding one or more members of nitrogen-containing bases to two or more members of acids.
  • the acid and nitrogen-containing base need not exist individually in a equimolar or equivalent amount, and one components thereof may exists in excess.
  • Every above-mentioned strength increasing agent is generally used in a form of aqueous solution thereof in the treatment of cellulose fiber or the products thereof.
  • the said strength increasing agent seemingly is impregnated in and adheres to cellulose fiber or products thereof in a form of a salt, a mixture of the salt and nitrogen-containing base or a mixture of the salt and acid.
  • FIG. 1 shows the relationship between the strength of heattreated cloth obtained and the temperature of heat treatment, in the heat treatment of viscose rayon cloth
  • FIG. 2 the relationship between the strength of heat-treated cloth obtained and the adhesion percentage of ammonium bisulfate, ammonium sulfite and ammonium thiosulfate to the starting material cloth, in the heat treatment of viscose rayon cloth precedingly treated individually with ammonium bisulfate, ammonium sulfite and ammonium thiosulfate wherein a represents the case of ammonium sulfite, b the case of ammonium thiosulfate and c the case of ammonium bisulfate;
  • FIG. 3 the strength of heat-treated cloth obtained and the composition of ammonium salt-nitrogen-containing base system strength increasing agent in the heat treatment of viscose rayon cloth precedingly treated with the said strength increasing agent;
  • a represents the case of ammonium sulfite-urea system
  • b the case of ammonium sulfite-thiourea system
  • c the case of ammonium bisulfate-urea system
  • d the case of ammonium bisulfite-triethanol-amine system
  • FIG. 4 the strength of heat-treated cloth obtained and the adhesion percentage of sulfuric acid-nitrogen-containing base system strength increasing agent, in the heat treatment of viscose rayon cloth precedingly treated with the said strength increasing agent
  • a represents the case of sulfuric acidurea system
  • b the case of sulfuric acid-guanidine system
  • c the case of sulfuric acid-thiourea system
  • d the case of sulfuric acid-triethanolamine system
  • e the case. of sulfuric acidethylenediamine system
  • f the case of sulfuric acid-dicyandiamidine system
  • FIG. 5 the relationship between the strength of heat-treated cloth obtained and the composition of sulfuric acid-nitrogencontaining base system strength increasing agent in the heat treatment of viscose rayon cloth precedingly treated with the said strength increasing agent, wherein a represents the case of sulfuric acid-urea system, b the case of sulfuric acidtriethanolamine system and c the case of sulfuric acid-thiourea system; and
  • FIG. 6 the relationship between the strength of heat-treated cloth obtained and the composition of sulfamic acid-nitrogencontaining base system strength increasing agent, in the heat treatment of viscose rayon cloth precedingly treated with the said strength increasing agent, wherein a represents the case of sulfamic acid-triethanol amine system, b the case of sulfamic acid-urea system, c the case of sulfamic acid-urea (40 percent system and d the case of sulfamic acid-thiourea system.
  • FIG. 1 is an example which shows this tendency, and shows the relationship between the obtained tensile strength of heat-treated cloth and the temperature of heat treatment when viscose rayon diagonal cloth is heated up to the specified temperatures at a heating rate of C./min. and heat-treated at each temperature for 1 hour respectively.
  • This figure shows that the strength of viscose rayon diagonal cloth suddenly falls at a high heat treatment temperature and that an inflection point of the strength exists in the vicinity of 280C.
  • the heat treatment of cellulose fiber soaked in the above-mentioned strength increasing agent includes the temperature of remarkable strength reduction at a temperature of 160 to 180C, but suddenly recovers the strength at a temperature of higher than 180C.
  • this heat treatment of such processed fiber affords flexible heat-treated fiber having high strength at a temperature of 280C.
  • the strength increasing action of strength increasing agent relates to the adhesion percentage of strength increasing agent to the starting material cellulose fiber and the mixing ratio of ammonium salt and nitrogen-containing base or acid and nitrogen-containing base of the above-mentioned strength increasing agent of the present invention in the case of the strength increasing agents of paragraphs (2) and 3).
  • Such strength increasing action of the strength increasing agent of the present invention in general, increases together with the increase of the adhering amount thereof to cellulose fiber or the products thereof. Too much adhesion thereof, however, involves such secondary disadvantages as the starting material fiber or the products thereof being hardened too much resulting in the inconvenience in the handling thereof or as the soaking treatment becoming difficult, but the strength increasing effect is unaltered.
  • ammonium salt-nitrogen-containing base system or acid-nitrogen-containing base system is used as a strength increasing agent, it is observed that the strength of heat-treated fiber or the products thereof increases in harmony with the increase of the adhering amount of the strength increasing agent to the starting material fiber or the products thereof but that, when the adhesion percentage of strength increasing agent exceeds a certain value, the strength of heat-treated fiber or the products thereof decreases slowly or suddenly.
  • the strength increasing action thereof also depends on the mixing ratio of nitrogen-containing base to acid or ammonium salt, and it is recognized that, with respect to every strength increasing agent, the most suitable mixing ratio or the preferable mixing ratio exists.
  • the strength increasing agent of the present invention having the above-mentioned strength increasing action is subsequently described concretely.
  • FIG. 2 when viscose rayon diagonal cloth is soaked in each aqueous solution of ammonium bisulfate, ammonium sulfite and ammonium thiosulfate, and thereafter heat-treated in airat 250C. for 2 hours and further at 300C. for 1 hour, show the relationship between the adhesion percentage of each ammonium salt to the starting material diagonal cloth and the strength of heat-treated cloth.
  • This figure excluding the case of ammonium bisulfate, shows that the strength of heat-treated cloth increases in accordance with the increase of adhesion percentage of ammonium salt.
  • ammonium bisulfate when the adhesion percentage is not higher than about 10 percent, the strength of heat-treated cloth increases, but when it is higher than about 10 percent, the strength of heat-treated cloth decreases. Therefore, in the case of using ammonium bisulfate, the soaking treatment should be carried out so as to give about 10 percent of adhesion percentage. It is considered that such behavior of ammonium bisulfate is due to its brittle action against cellulose the action of acidic I-I existing in the molecule of ammonium bisulfate. For example, viscose rayon cloth molders if it is soaked in an aqueous solution of ammonium bisulfate, dried and allowed to stand at room temperature for 1 day or more without any further processing.
  • ammonium bisulfite also contains acidic 1-1 in its molecule, it shows the same behavior as ammonium bisulfate and has substantially the same strength increasing action as ammonium bisulfate.
  • Every ammonium salt mentioned above may be used in the form of mixture.
  • the strength increasing action of each ammonium salt depends on the mixing ratio of each ammonium salt.
  • this mixing does not recognizably exert an especial geometrical effect.
  • the strength increasing action of a mixture system of ammonium salt and nitrogen-containing base namely, a mixture system of ammonium sulfate, ammonium bisulfate, ammoniurn sulfite, ammonium bisulfite, ammonium thiosulfate, am-
  • Table 1 shows the results when viscose rayon diagonal cloth (thickness 0.5 mm) is treated with strength increasing agents of ammonium imidosulfonate and ammonium imidosulfonateurea (weight ratio 2:1) system, and heat-treated in air at 250C. for 2 hours and further at 300C. for 2 hours.
  • salt-nitrogen-containing base system or the later-mentioned acid-nitrogen-containing base system strength increasing agent may be a general phenomenon of such cases.
  • Tables 2 and 3 show the results when viscose rayon diagonal cloth (thickness; 0.5 mm) is treated with a strength increasing agent prepared by mixing urea, thiourea or triethanol amine with ammonium sulfate, ammonium sulfamate or ammonium imidosulfonate, and thereafter heattreated in air at 250C. for 2 hours and further at 300C. for 2 hours.
  • a strength increasing agent prepared by mixing urea, thiourea or triethanol amine with ammonium sulfate, ammonium sulfamate or ammonium imidosulfonate
  • FIG. 3 shows the case of mixing urea, thiourea or triethanolamine with ammonium sulfite and mixing urea with ammonium bisulfate.
  • FIG. 3 when viscose rayon diagonal cloth is soaked in each aqueous solution of the above-mentioned strength increasing agents so as to produce almost constant adhesion percentage of ammonium salt and to vary the adhesion ratio of base, wrung, dried, and thereafter heattreated in air at 250C. for 2 hours and further at 300C. for 1 hour, shows the relationship between the strength of heattreated cloth and the composition of each strength increasing agent.
  • the adhesion percentages of ammonium salt to the starting material diagonal cloth, with respect to each strength increasing agent are as follows:
  • ammonium thiosulfate As the ammonium salt component, the effect of base almost identical with that of the cases of other ammonium salt, can be obtained as well.
  • ammonium thiosulfate-base system is to be described in Examples below.
  • FIG. 3 shows the results of the case where the adhesion percentage of ammonium sulfite is from 16 to 18 percent, while, as is clear from FIG. 2, the strength of heat-treated cloth of the case of single ammonium sulfite system increases together with the increase of the adhesion percentage of said ammonium sulfite to the starting material cloth.
  • the treatment of further increasing the adhesion percentage of ammonium sulfite may afford the further higher strength to the heat-treated cloth.
  • the adhesion percentage is too high, the strength of heat-treated cloth rather decreases, and thus the adhesion percentage exceeding the limit should be avoided.
  • the most suitable adhesion percentage of such a mixture system may easily be determined by experiment.
  • Other ammonium salt-base systems may be under the identical conditions, and the most suitable adhesion percentage with respect to each system may easily be determined by experiment.
  • the most effective base when combined with ammonium salt, is urea and thiourea.
  • Triethanolamine, guanidine and triethylamine in this case, belong to a second class as the compound exerting the base effect.
  • Dicyandiamide, dicyandiamidine, aniline, pyridine and the like belong to the group of compounds exerting relatively low base effect.
  • ammonium salt-nitrogen-containing base system strength increasing agent is not limited within the mixture systems comprising only one member of ammonium salts and only one member of nitrogen-containing bases, but includes the systems obtained by mixing two or more members of nitrogen-containing bases with one member of ammonium salts and the systems obtained by mixing one or more members of nitrogen-containing bases with two or more members of ammonium salts.
  • FIG. 4 when viscose rayon diagonal cloth is soaked in a respective aqueous solution of sulfuric acid-urea system (molar ratio; 1:2.75), sulfuric acid-thiourea system (molar ratio; 1:1), sulfuric acid-triethanolamine system (molar ratio; 1:3), sulfuric acid guanidine [NI-I:C(NH -H SO,), sulfuric acid ethylenediamine [NH CH CH NH -H SO,) and sulfuric acid-dicyandiamidine [NI-I CS NH NH CONH :I-I SO -2I-I O), wrung, dried and thereafter heat-treated in air at 250C. for 2 hours and further at 300C.
  • sulfuric acid-urea system moleic acid-urea system
  • sulfuric acid-thiourea system molar ratio; 1:1
  • sulfuric acid-triethanolamine system molar ratio; 1:3
  • sulfuric acid guanidine [NI-I:C(NH -H SO,), sulfuric acid
  • FIG. 5 when viscose rayon diagonal cloth is soaked in each aqueous solution of sulfuric acid-urea system, sulfuric acid-thiourea system and sulfuric acid-triethanolamine system strength increasing agents so that the adhesion percentages of sulfuric acid which is the acid component of the said strength increasing agents, are almost constant such as 15.0 percent, 1 1.3 percent and 5.9 percent, respectively, and so that the adhesion percentages of base components thereof are varied, and thereafter heat-treated in the manner as above, shows the relationship between the mixing ratio of each strength increasing agent and the strength of heat-treated cloth.
  • FIG. 6 shows the case of sulfamic acid-base system.
  • FIG. 6 when viscose rayon diagonal cloth is soaked in an aqueous solution of respective strength increasing agent prepared by mixing urea, thiourea or triethanolamine with sulfamic acid at respective suitable mixing ratio and subsequently heat-treated in air at 250C. for 2 hours and further at 300C. for 1 hour, shows the relationship between the strength of heat-treated cloth and the composition of the above-mentioned strength increasing agent, wherein the adhesion percentage of the strength increasing agent of respective mixing ratio to the starting material diagonal cloth is controlled so as to make the adhesion percentage of sulfamic acid almost constant (about 20 percent) and the adhesion percentage of base varied.
  • the adhesion percentage of the strength increasing agent of respective mixing ratio to the starting material diagonal cloth is controlled so as to make the adhesion percentage of sulfamic acid almost constant (about 20 percent) and the adhesion percentage of base varied.
  • FIGS. 4 to 6 show the fact that, in the case of such strength increasing agents, the strength of heattreated cloth also relates to the adhesion percentage of strength increasing agent and to the composition thereof, as in the case of the aforesaid single ammonium salt system or ammonium salt-nitrogen-containing base system.
  • FIG. 4 shows that the strength of heat-treated cloth increases in harmony with the increase of adhesion percentage of strength increasing agent and that, when the adhesion percentage exceeds a certain value, the strength gradually or suddenly decreases.
  • FIG. 6 shows that, when the mixing molar ratio of urea to sulfamic acid is about 0.5 to 1.5, preferably about 0.8 to L5, sulfamic acid with about 40 percent adhesion percentage exerts stronger strength increasing action than that with about percent adhesion percentage.
  • FIGS. 5 and 6 show that, with respect to every strength increasing agent, the most suitable or preferable mixing ratio exists.
  • This most suitable or preferable mixing ratio is not necessarily limited within the ratio obtained when acid and base exist in equimolar amount, but includes the case where the acid or base exists in excess by molar ratio.
  • the strength increasing agent of sulfurous acid-base system behaves in the same way as that of sulfuric acid-base system and exerts almost identical strength increasing action. This is described in Examples below.
  • the above-mentioned acid-nitrogen-containing base system strength increasing agent is not limited within the system comprising only one member of acids and only one member of nitrogen-containing bases, but includes the systems obtained by adding 2 or more member of nitrogen-containing bases to one member of acids and the systems obtained by adding one or more members of nitrogen-containing bases to two or more members of acids.
  • a nitrogen-containing base in itself which is combined with acid or ammonium salt, does not possess strength increasing action.
  • the nitrogencontaining base is combined with acid or ammonium salt, if the said acid component or ammonium salt component is hydrochloric acid, nitric acid, phosphoric acid, formic acid, acetic acid, trifluoroacetic acid, ammonium nitrate, ammonium chloride, ammonium acetate, ammonium oxalate, ammonium formate or the like, the strength increasing action is not also exerted. Therefore, the above-defined acids or ammonium salts which exert strength increasing action by the combination thereof with nitrogen-containing base are only such specific compounds as the acids or ammonium salts of the present invention.
  • the present invention relates to a process for carbonizing the cellulose fiber or the products thereof preceedingly treated with a strength increasing agent described in detail above by the heat treatment at a temperature of 200 to 350C. in an oxidative atmosphere and subsequently at a temperature up to about 1,000C. in an inert atmosphere and, if necessary, carbonizing or graphitizing the thus obtained carbonized fiber or the products thereof by the further heat treatment at a temperature not less than about 1,000C. in an inert atmosphere.
  • the above-mentioned treatment of starting material fiber or the products thereof with a strength increasing agent in advance to the heat treatment thereof enables the heat treatment at such a high heating rate as the heating up to a temperature of about l,O00C.( in an inert atmosphere) after the heat treatment at a temperature of 200 to 350C. in an oxidative atmosphere being 1 to 5C/min, which has not been achieved in any way by the conventional processes.
  • this is an industrially extremely advantageous process.
  • the heating rate of the said treated substance is not necessarily limited within the above-mentioned treating rate.
  • heat treat ment at a lower heating rate results in heat-treated fiber or the products thereof having higher strength
  • this invention includes the case of heat treatment at a heating rate of less than lC/min.
  • Carbon fiber or graphite fiber with a carbon content of about 95 percent or above can be produced by heat-treating the carbon-like fiber prepared according to the above-mentioned process of the present invention (carbon content: up to about percent) at a temperature of higher than about 1,000C. according to the conventional process. Even in this case, however, if the highly strong carbon-like fiber produced by the process of the present invention is used as the starting material, the stronger carbon fiber or graphite fiber than the conventional carbon or graphite fiber can evidently be obtained.
  • the present invention affords a process for heat-treating the cellulose fiber or the products thereof treated with a strength increasing agent, in at first an oxidative atmosphere and subsequently at a higher temperature in an inert atmosphere, and the oxidative atmosphere herein is generally represented by air.
  • an inert gas such known inert gases as nitrogen, helium, argon, carbon dioxide and the like may be used.
  • air incorporated in the heat treatment furnace air initially contained in the cloth or oxygen contained in an inert gas may cause the deterioration of heattreated fiber or the products thereof due to the oxidation by said air or oxygen.
  • Such a heat treatment may often afford the lower strength to the heat-treated fiber or the products thereof than the experimental heat treatment where the heat treatment atmosphere is completely replaced by an inert gas.
  • the starting material fiber or the products thereof may be soak-treated with a strength increasing agent, to which is precedingly added such a com pound as ammonium phosphates, guanidine phosphate, aluminum ammonium sulfate, tetrakis (hydroxymethyl) phosphonium chloride (THPC) and the like, which is called as a flame resistance improving agent clarified in the present inventors invention relating to the process for the production of flame-resistant fiber.
  • a strength increasing agent such as ammonium phosphates, guanidine phosphate, aluminum ammonium sulfate, tetrakis (hydroxymethyl) phosphonium chloride (THPC) and the like, which is called as a flame resistance improving agent clarified in the present inventors invention relating to the process for the production of flame-resistant fiber.
  • the soaking treatment of the starting material cellulose fiber or the products thereof with an aqueous solution of the above-mentioned compound called as a flame resistance improving agent affords the heat-treated fiber or the products thereof which do not involve not only the combustion but also the ember combustion and the reduction to ashes, in other words. the heattreated fiber or the'products thereof excellent in oxidation resistance.
  • the present invention is applied after treating cellulose fiber or the products thereof with a treating agent prepared by adding the above-mentioned flame resistance improving agent to a strength increasing agent of the present invention having been described in detail, even if oxygen is contained in an inert atmosphere, the heat-treated fiber or the products thereof excellent in oxidation resistance due to the presence of flame resistance improving agent can be produced, and thereby the oxidative deterioration due to said oxygen or air contained in the starting material fiber or the products thereof may be inhibited so as to give preferable results.
  • Table 4 shows the results of the cases where diammonium .hydrogen phosphate, triammonium phosphate, guanidine phosphate, THPC and aluminum ammonium sulfate are employed as a flame resistance improving agent.
  • the case of ammonium dihydrogen phosphate also exerts the identical action.
  • 2 kinds or more of flame resistance improving agents may simultaneously be used, and the amount of addition thereof may be small as compared with that of strength increasing agent.
  • the condition of heat treatment of the present invention should suitably be determined depending on the texture, shape, etc. of the starting material fiber or the products thereof. For example, when a big rattan, thick woven stuff, thick nonwoven cloth or felting is heat-treated, heat generated by the pyrolysis thereof is liable to be stored up inside the texture thereof, and thereby the abnormal heat generation is involved so that the temperature controlling may sometimes become difficult. in this case, such a method as reducing the heating rate should be applied.
  • the properties concerning the strength of heat-treated fiber or the products thereof obtained by the present invention depend on the kind of strength increasing agents, the adhesion percentage thereof, mixing ratio thereof, heat treatment conditions and so on, and in addition thereto relate to the micro-structure of starting material cellulose. That is, generally, the higher the degree of orientation of starting material cellulose, the larger the strength of the heat- 0 products thereof are not limited within the fiber or the treated fiber or the products thereof and the smaller the elongation thereof.
  • the heat-treated fiber of such a highly crystalline cellulose fiber as polynosic fiber, cotton or the like is generally brittle, but such brittleness can be avoided if such crystalline starting material fiber is precedingly treated according to such a known method as mercerizetion or the like to reduce the degree of crystallization thereof and then heattreated.
  • the starting material fiber or the products thereof singly comprising cellulose fiber include the fiber or the products thereof which is prepared by mixing such a known fiber capable of being carbonated by pyrolysis as polyacrylonitrile fiber, polyvinylalcohol fiber or the like with cellulose fiber.
  • cellulose fiber includes not only the fiber singly comprising cellulose fiber but also all of the fibers composed of the every above-mentioned materials, and represents every kind of the above-mentioned fibers.
  • the present invention in the production of carbon-like fiber, carbon fiber, graphite fiber or the products thereof from cellulose fiber, enables the preparation of carbon-like fiber or the products thereof having the strength several times higher than the case of using nontreated cellulose fiber as a starting material even at a temperature of 200 to 500C. which belongs to the most dangerous temperature range wherein the mechanical properties of the carbonated fiber may be deteriorated, by precedingly treating cellulose fiber or the products thereof with a strength increasing agent provided for in the present invention or a treating agent prepared by adding a flame resistance improving agent to said strength increasing agent, and subsequently by heattreating the thus treated fiber or the products thereof at a temperature of 200 to 350C.
  • Diagonal cloth comprising viscose rayon fiber (denier of monofilament: 1.5 d) spun yarn (thread density: longitudinal, 36 threads/2.5 cm.of width, transverse, 36 threads/ 2.5 cm. of width; weight 280 g/m) was soaked in an aqueous solution dissolving ammonium sulfite and ammonium dihydrogen phosphate (30 weight percent based on the weight of ammonium sulfite), and the thus soaked cloth was wrung at a wringing percentage of l00 percent and subsequently dried at C. for 3 hours so as to obtain a treated cloth having an adhesion percentage of solid component being 57.6 percent.
  • the thus treated cloth was heated-treated in air in a hot wind drying oven at 250C. for 2 hours and further at 300C. for 1 hour, and thereafter the thus heat-treated cloth was washed and dried.
  • the thus obtained heat-treated cloth in air had a weight loss of 52.1 percent, a tensile strength of 20.2 kg/2.5 cm. of width and the above-defined flame resistance being A, and was the heat-treated cloth excellent in durability to oxidation
  • the said heat-treated cloth in air was charged in a stainless steel cylinder equipping a nitrogen charging inlet and an opening connected with a vacuum pump, and the air in the cylinder was replaced by nitrogen by the several times repeated evacuation and nitrogen introduction. Thereafter the cloth in the cylinder was heated at a heating rate of 5C/min.
  • the thus obtained heat-treated cloth had a weight loss of 52.7 percent (based on the weight of the above-mentioned heat-treated cloth in air) and a tensile strength of 6.66 kg/2.5 cm. of width.
  • the non-treated said starting material diagonal cloth was also heat-treated in air in the same way as above (weight loss 72.0 percent tensile strength: 6.4 kg/2.5 cm. of width), and thereafter the thus heat-treated cloth was heated in nitrogen up to 1,000C. and heat-treated at this temperature for 1 hour.
  • the thus obtained heat-treated cloth had a weight loss of 53.6 percent (based on the weight of the heattreated cloth in air) and a tensile strength of 1.8 kg/2.5 cm. of width.
  • EXAMPLE 12 The same starting material diagonal cloth as in Example 1, was soaked in an aqueous solution of treating agent comprising 1,000 g. of ammonium sulfate, 500 g. of urea, 75 g. of tetrakis (hydroxymethyl) phosphonium chloride and 3,500 c.c. of water, wrung by a mangle and then dried so as to obtain treated cloth with the adhesion percentage of solid component being 50.4 percent. Subsequently, the thus treated cloth was heat-treated in air in the same way as in Example 1 so as to obtain heat-treated cloth in air having a weight loss of 53.7 per cent, a tensile strength of 18.8 kg/2.5 cm. of width and the flame resistance being A.
  • treating agent comprising 1,000 g. of ammonium sulfate, 500 g. of urea, 75 g. of tetrakis (hydroxymethyl) phosphonium chloride and 3,500 c.c. of water, wrung by a mangle
  • the said heat-treated cloth in air in the same way in nitrogen as in Example 1, was heated at a heating rate of C/min. up to 1,000C. and heattreated at this temperature for 1 hour.
  • the thus obtained heattreated cloth had a weight loss of 52.1 percent (based on the weight of the above-mentioned heat-treated cloth in air) and a tensile strength of 9.84 kg/2.5 cm. ofwidth.
  • EXAMPLE 3 The same starting material cloth as in Example 1 was soaked in an aqueous solution of treating agent comprising 410 g. of sulfurous acid (net weight in sulfurous acid water), 750 g. of urea, 30 g. of diammonium hydrogen phosphate and 2,000 cc. of water, wrung by a mangle and then dried so as to obtain the heat-treated cloth with the adhesion percentage of solid component being 34.3 percent. Subsequently, this at a heating rate of 5C/min. up to l,000C. and heat-treated at this temperature for 1 hour. The results are shown in the following table.
  • EXAMPLE 5 The same starting material diagonal cloth as in Example 1 was soaked in an aqueous solution of each strength increasing agent, taken out, wrung and dried. Thereafter, the thus treated cloth was heat-treated in a hot wind drying oven under the same conditions as in Example 1, and then the thus heat treated cloth was washed and dried so as to obtain the heattreated cloth in air having the flame resistance of B. Subsequently, this heat-treated cloth in air was charged in the same stainless steel cylinder as that of Example 1, the air in which was then replaced by nitrogen, thereafter heated at a heating rate of 5C/min. up to 1,000C. and heat-treated at this temperature for 1 hour. The results are shown in the following table. Provided that the weight loss of heat-treated cloth at 1,000C. is a value based on the weight of heat-treated cloth in air.
  • EXAMPLE 6 treated cloth was heat-treated in air in the same way as in Example 1 so as to obtain the heat-treated cloth in air having a weight loss of 44.6 percent, a tensile strength of 18.8 kg/2.5 cm. of width and the flame resistance of A. Thereafter, the said heat-treated cloth in air, in the same way in nitrogen as in Example 1, was heated up to l,0O0C. and heat-treated at this temperature for 1 hour. The thus obtained heat-treated cloth had a weight loss of 51.7 percent (based on the weight of the above-mentioned heat-treated cloth in air) and a tensile strength of 9.73 kg/2.5 cm. ofwidth.
  • EXAMPLE 4 The same starting material diagonal cloth as in Example 1 was soaked in each aqueous solution of strength increasing agents, taken out, wrung and dried. Thereafter the thus treated cloth was heat-treated in a hot wind drying oven under the same conditions as in Example 1, and then the thus heattreated cloth was washed and dried so as to obtain the heattreated cloth in air having the flame resistance of B. Subsequently, this heat-treated cloth in air was charged in the same stainless steel cylinder as that of Example 1, the air therein was then replaced by nitrogen, and thereafter heated thus treated tow was heat-treated in air at 220C. for 1 hour, at
  • EXAMPLE 7 tube-shaped heating body, a weight was suspended at the Diagonal cloth (thread density: 41 X threads/in thickness 0.77 mm) comprising strong rayon yarn (denier 1.79 d X 750 filament tensile strength 3.55 g/d. ;elongation 17.9 percent) was soaked in an aqueous solution of ammonium sulfite with a concentration of 400 g/l, wrung by a mangle and then dried so as to obtain treated cloth with the adhesion percentage of ammonium sulfite being 37.2 percent. The thus treated cloth was heat-treated in air by passing through the zone at 220C. and the zone at 260C.
  • the thus obtained black heat-treated cloth had a tensile strength of 27.5 kg/2.5 cm. of width, and the elementary analysis thereof was as follows.
  • this black heat-treated cloth was charged in the same stainless steel cylinder as in Example 1, the air in which was sufficiently replaced by nitrogen so as to remove the air contained in the said heat-treated cloth, thereafter heated at a heating rate of 2.5C/min. up to 600C. and at 5C/min. over a temperature range of from 600 to 1,000C, and heat-treated at 1,000C. for 1 hour.
  • the tensile strength of heat-treated cloth obtained was 18.5 kg/2.5 cm. of width.
  • the strength and elongation of the thread pulled out of this heat-treated cloth and the elementary analysis were as follows:
  • the said bundle of carbon-like fiber in the same way as in Example 7, was heated up to 2,500C. and heattreated.
  • the thus obtained heat-treated fiber was highly flexible graphite-like fiber with a tensile strength of 3.27 g/d, an elongation of 0.48 percent and a carbon content of 99.9 percent.
  • EXAMPLE 9 The same starting material cloth as in Example 7 was soaked in an aqueous solution of treating agent comprising 490 g. of sulfuric acid, 600 g. of urea, 40 g. of triammonium phosphate and 2,000 cc. of water, wrung by a mangle and then dried to obtain the treated cloth with the adhesion percentage of solid component being 36.6 percent.
  • the elementary analysis of this heat-treated cloth was as follows:
  • this black heat-treated cloth was charged in the same stainless steel cylinder as in Example 7, the air in which was sufiiciently replaced by nitrogen so as to remove the air contained in the said heat-treated cloth, thereafter, under the same conditions as in Example 7, heated up to 1,000C. and heat-treated. Threads were pulled out of the thus obtained heat-treated cloth, and the measurements on the strength and elongation of monofilament and on the elementary analysis thereof were carried out. The results were as follows:
  • step (a) treating cellulose fiber or the products thereof with a strength increasing agent selected from the group consistheat-treating the product of step (a) at a temperature between about 200C. and about 350C. in an oxidative atmosphere for a period of time sufficient to increase the strength of the fiber; and
  • step (b) heat-treating the product of step (b) in an inert atmosphere at a temperature of at least about 400C for a period of time sufficient to bring about carbonization.
  • organic nitrogen base is selected from the group consisting of urea, a urea derivative, thiourea, a thiourea derivative, and an amine.
  • the strength increasing agent includes a flame resistance improving agent comprising at least one compound selected from the group consisting of ammonium phosphate, guanidine phosphate, aluminum ammonium sulfate and tetrakis (hydroxymethyl) phosphonium chloride.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
  • Chemical Or Physical Treatment Of Fibers (AREA)
US869196A 1968-11-06 1969-10-24 Process for carbonizing cellulose fiber or the products thereof Expired - Lifetime US3661616A (en)

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Cited By (10)

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US4251589A (en) * 1979-09-05 1981-02-17 Charles Romaniec Production of a substantially inert flexible textile material
US4264320A (en) * 1978-06-07 1981-04-28 Fireproof Products Limited Production of black flame-resistant flexible textile materials
US4603041A (en) * 1984-07-19 1986-07-29 E. I. Du Pont De Nemours And Company Cyclization of acrylic fiber
US4723959A (en) * 1984-11-07 1988-02-09 Nitto Boseki Co., Ltd. Non-inflammable fiber materials and process for producing the same
USH1052H (en) 1989-06-30 1992-05-05 Method for stabilization of pan-based carbon fibers
US5521008A (en) * 1993-11-25 1996-05-28 Electrophor, Inc. Manufacture of activated carbon fiber
WO1997020768A1 (en) * 1995-12-07 1997-06-12 Sandia Corporation Methods of preparation of carbon materials for use as electrodes in rechargeable batteries
US9190222B1 (en) * 2012-06-07 2015-11-17 North Carolina Agricultural And Technical State University Production of carbonaceous nano-fibrous materials with ultra-high specific surface area from alkali (Kraft) lignin
US10641026B2 (en) 2017-03-07 2020-05-05 Cmech (Guangzhou) Ltd. Automatic door stopping-closing device and door
WO2023031589A1 (en) * 2021-09-01 2023-03-09 Grown Graphene Limited Method for preparing a carbon nanomaterial

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Publication number Priority date Publication date Assignee Title
CN113249825A (zh) * 2021-05-10 2021-08-13 深圳市华鼎星科技有限公司 一种应用于触控屏的高导电碳纤维及其制备方法及其应用

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US3297405A (en) * 1963-11-21 1967-01-10 Siemens Planiawerke Ag Method of carbonizing animal fiber materials
US3305315A (en) * 1962-09-20 1967-02-21 Union Carbide Corp Process for manufacturing flexible carbonaceous textile material
US3333926A (en) * 1963-10-30 1967-08-01 Union Carbide Corp Process for carbonizing cellulosic textile materials
US3441378A (en) * 1966-05-10 1969-04-29 Union Carbide Corp Process for the manufacture of carbon textiles
US3461082A (en) * 1964-10-10 1969-08-12 Nippon Kayaku Kk Method for producing carbonized lignin fiber
US3479150A (en) * 1965-07-14 1969-11-18 Hitco Carbonization method for cellulosic fibers
US3479151A (en) * 1966-01-03 1969-11-18 Hitco Method of carbonizing fibrous cellulosic materials
US3527564A (en) * 1968-04-15 1970-09-08 Stevens & Co Inc J P Process for carbonizing fibrous materials
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US3305315A (en) * 1962-09-20 1967-02-21 Union Carbide Corp Process for manufacturing flexible carbonaceous textile material
US3333926A (en) * 1963-10-30 1967-08-01 Union Carbide Corp Process for carbonizing cellulosic textile materials
US3297405A (en) * 1963-11-21 1967-01-10 Siemens Planiawerke Ag Method of carbonizing animal fiber materials
US3461082A (en) * 1964-10-10 1969-08-12 Nippon Kayaku Kk Method for producing carbonized lignin fiber
US3479150A (en) * 1965-07-14 1969-11-18 Hitco Carbonization method for cellulosic fibers
US3532466A (en) * 1965-11-16 1970-10-06 Nat Res Dev Production of carbon fibres
US3479151A (en) * 1966-01-03 1969-11-18 Hitco Method of carbonizing fibrous cellulosic materials
US3441378A (en) * 1966-05-10 1969-04-29 Union Carbide Corp Process for the manufacture of carbon textiles
US3527564A (en) * 1968-04-15 1970-09-08 Stevens & Co Inc J P Process for carbonizing fibrous materials

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4264320A (en) * 1978-06-07 1981-04-28 Fireproof Products Limited Production of black flame-resistant flexible textile materials
US4251589A (en) * 1979-09-05 1981-02-17 Charles Romaniec Production of a substantially inert flexible textile material
US4603041A (en) * 1984-07-19 1986-07-29 E. I. Du Pont De Nemours And Company Cyclization of acrylic fiber
US4723959A (en) * 1984-11-07 1988-02-09 Nitto Boseki Co., Ltd. Non-inflammable fiber materials and process for producing the same
USH1052H (en) 1989-06-30 1992-05-05 Method for stabilization of pan-based carbon fibers
US5521008A (en) * 1993-11-25 1996-05-28 Electrophor, Inc. Manufacture of activated carbon fiber
WO1997020768A1 (en) * 1995-12-07 1997-06-12 Sandia Corporation Methods of preparation of carbon materials for use as electrodes in rechargeable batteries
US9190222B1 (en) * 2012-06-07 2015-11-17 North Carolina Agricultural And Technical State University Production of carbonaceous nano-fibrous materials with ultra-high specific surface area from alkali (Kraft) lignin
US10641026B2 (en) 2017-03-07 2020-05-05 Cmech (Guangzhou) Ltd. Automatic door stopping-closing device and door
WO2023031589A1 (en) * 2021-09-01 2023-03-09 Grown Graphene Limited Method for preparing a carbon nanomaterial

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Publication number Publication date
GB1275080A (en) 1972-05-24
DE1955474C3 (de) 1978-09-21
DE1955474B2 (de) 1978-01-12
DE1955474A1 (de) 1970-05-14

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