Carbon fiber precursor, method of producing carbon fiber precursor, method of producing stabilized fiber, and method of producing carbon fiber

Abstract

The carbon fiber precursor contains a crosslinked acrylamide-based polymer and has a gel fraction of 5% or more.

What is claimed is: 
     
         1 . A carbon fiber precursor, comprising a crosslinked acrylamide-based polymer and having a gel fraction of 5% or more. 
     
     
         2 . The carbon fiber precursor according to  claim 1 , wherein the gel fraction is 98% or less. 
     
     
         3 . The carbon fiber precursor according to  claim 1 , wherein the crosslinked acrylamide-based polymer contains 30 mol % or more of an acrylamide-based monomer unit. 
     
     
         4 . The carbon fiber precursor according to  claim 1 , wherein the crosslinked acrylamide-based polymer is a copolymer of an acrylamide-based monomer, a vinyl cyanide-based monomer, and an unsaturated carboxylic acid. 
     
     
         5 . A method of producing a carbon fiber precursor, the method comprising irradiating an acrylamide-based polymer fiber with an active ray to crosslink an acrylamide-based polymer contained in the acrylamide-based polymer fiber. 
     
     
         6 . The method of producing the carbon fiber precursor according to  claim 5 , wherein the acrylamide-based polymer contains 30 mol % or more of an acrylamide-based monomer unit. 
     
     
         7 . The method of producing the carbon fiber precursor according to  claim 5 , wherein the acrylamide-based polymer is a copolymer of an acrylamide-based monomer, a vinyl cyanide-based monomer, and an unsaturated carboxylic acid. 
     
     
         8 . A method of producing a stabilized fiber, comprising subjecting the carbon fiber precursor according to  claim 1  to heat treatment in an oxidizing atmosphere. 
     
     
         9 . A method of producing a carbon fiber, the method comprising subjecting the flame resistant fiber produced by the method of producing the stabilized fiber according to  claim 8  to carbonization treatment.