초록 ▼

A preoxidized fiber suitable for producing carbon fiber, comprising preoxidizing an acrylic fiber having thereon an ammonium salt of a fatty ester represented by formula [A] and [B] ##STR## wherein R 1 is an aliphatic hydrocarbon group having from 11 to 17 carbon atoms; R 2 and R 3 can each be hydro

A preoxidized fiber suitable for producing carbon fiber, comprising preoxidizing an acrylic fiber having thereon an ammonium salt of a fatty ester represented by formula [A] and [B] ##STR## wherein R 1 is an aliphatic hydrocarbon group having from 11 to 17 carbon atoms; R 2 and R 3 can each be hydrogen, a lower alkyl group, a hydroxyethyl group, or an hydroxyisopropyl group; and X.crclbar. is an anion.

대표청구항 ▼

1. A process for producing a preoxidized fiber, comprising contacting an acrylic fiber with a solution or dispersion of an ammonium salt of a fatty ester at a temperature of from 20° to 70° C., which solution or dispersion is at a pH of 4 or less, which solution or dispersion contains said ammonium

1. A process for producing a preoxidized fiber, comprising contacting an acrylic fiber with a solution or dispersion of an ammonium salt of a fatty ester at a temperature of from 20° to 70° C., which solution or dispersion is at a pH of 4 or less, which solution or dispersion contains said ammonium salt of a fatty ester in an amount sufficient to provide from 0.01 to 0.5%, based on the weight of the fiber, of said ammonium salt of a fatty ester on said fiber, said ammonium salt of a fatty ester being represented by formula [A] ##STR## wherein R 1 is an aliphatic hydrocarbon group having from 11 to 17 carbon atoms; R 2 and R 3 can each be hydrogen, a lower alkyl group, a hydroxyethyl group, or an hydroxyisopropyl group; and X .crclbar. is an anion, drying said fiber, and thereafter preoxidizing said fiber. 2. A process as in claim 1, in which the acrylic fiber consists of a polymer obtained from at least 95 mol% acrylonitrile and not more than 5 mol% vinyl monomer copolymerizable with acrylonitrile. 3. A process as in claim 2, in which the vinyl monomer is at least one member selected from the group consisting of methyl acrylate, ethyl acrylate, vinyl acetate, acrylic acid, methacrylic acid, itaconic acid, and salts thereof, sodium allylsulfonate, and sodium methallylsulfonate, vinyl pyridine, and vinyl imidazole. 4. A process as in claim 1, in which X .crclbar. in the formula is a chlorine ion, an acetate ion, a lactate ion, a phosphate ion, a sulfate ion, a borate ion, a nitrate ion, or a phosphoryldioxyethanol ion. 5. A process as in claim 1, in which said lower alkyl group has from 1 to 3 carbon atoms. 6. A process as in claim 1, in which the compound represented by formula [A] is selected from the group ##STR## 7. A process as in claim 1, in which the amount of the ammonium salt on the acrylic fiber is from less than 0.3%, based on the weight of the fiber. 8. A process as in claim 1, wherein said acrylic fiber being produced by treating a raw acrylic fiber at any stage from the removal of solvent to the finishing of production of the raw acrylic fiber or after the finishing of production of the raw acrylic fiber by a wet spinning. 9. A process as in claim 1, in which the pH is from 2 to 3.5. 10. A process as in claim 1, in which preoxidation is conducted at a temperature from 200° C. to 400° C. in an oxidizing atmosphere. 11. A process as in claim 10, in which preoxidation is conducted for from 0.1 to 1.5 hours. 12. A process as in claim 8, in which, after the treatment with the ammonium salt, the acrylonitrile fiber is subjected to heat treatment at from 200° C. to 300° C. to render the ammonium salt insoluble in water. 13. A process as in claim 12, in which the heat treatment is performed for from 0.7 to 2 minutes. 14. A process as in claim 12, in which the heat treatment is performed at from 230° C. to 300° C. 15. A process as in claim 12, in which the heat treatment is performed by raising the temperature at a rate of 10° C./sec or less after the temperature has reached 200° C. 16. A process as in claim 12, in which the heat treatment is performed by raising the temperature at a rate of from 1° to 5° C./sec after the temperature has reached 200° C. 17. A process as in claim 1, wherein R 1 is a linear saturated aliphatic carbon group. 18. A process as in claim 8, wherein the treatment of the acrylic fiber with ammonium salt is carried out by dipping the fiber in an aqueous solution or a dispersion of the ammonium salt. 19. Preoxidized fiber produced according to the process as claimed in claim 1. 20. A process as in claim 1, in which X.crclbar. in the formula is a phosphate ion, a sulfate ion, a borate ion or a phosphoryldioxyethanol ion.