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

Abstract

A means for resolution is a carbon fiber precursor containing a crosslinked diene-based polymer and having a gel fraction of 40% or more, and its application.

What is claimed is: 
     
         1 . A carbon fiber precursor, comprising a crosslinked diene-based polymer and having a gel fraction of 40% or more. 
     
     
         2 . The carbon fiber precursor according to  claim 1 , wherein a swelling magnification after immersion in toluene at 60° C. for 2 hours is a factor of 9.5 or less. 
     
     
         3 . The carbon fiber precursor according to  claim 1 , wherein the crosslinked diene-based polymer is a crosslinked product of a diene-based polymer containing a structural unit represented by the following Formula (1): 
       
         
           
           
               
               
           
         
         wherein R is a hydrogen atom or an organic group having from 1 to 20 carbon atoms. 
       
     
     
         4 . The carbon fiber precursor according to  claim 3 , wherein R in Formula (1) is a hydrogen atom or a methyl group. 
     
     
         5 . A method of producing a carbon fiber precursor, the method comprising irradiating a polymer fiber, including a diene-based polymer containing a structural unit represented by the following Formula (1), with radiation having a dose of 20 kGy or more: 
       
         
           
           
               
               
           
         
         wherein R is a hydrogen atom or an organic group having from 1 to 20 carbon atoms. 
       
     
     
         6 . The method of producing a carbon fiber precursor according to  claim 5 , wherein R in Formula (1) is a hydrogen atom or a methyl group. 
     
     
         7 . A method of producing a stabilized fiber, the method comprising subjecting a fiber bundle of the carbon fiber precursor according to  claim 1  to a heat treatment in an oxidizing atmosphere. 
     
     
         8 . A method of producing a stabilized fiber, the method comprising:
 producing a carbon fiber precursor by the method of producing a carbon fiber precursor according to  claim 5 ; and   subjecting a fiber of the carbon fiber precursor to a heat treatment in an oxidizing atmosphere.   
     
     
         9 . A method of producing a carbon fiber, the method comprising:
 producing a stabilized fiber by the method of producing a stabilized fiber according to claim  7 ; and   subjecting the stabilized fiber to a carbonization treatment.   
     
     
         10 . A method of producing a carbon fiber, the method comprising:
 producing a carbon fiber precursor by the method of producing a carbon fiber precursor according to  claim 5 ;   producing a stabilized fiber by subjecting a fiber of the carbon fiber precursor to a heat treatment in an oxidizing atmosphere; and   subjecting the stabilized fiber to a carbonization treatment.   
     
     
         11 . A stabilized fiber, comprising a structure derived from a crosslinked diene-based polymer and having a fusion rate of 30% or less. 
     
     
         12 . A method of producing a carbon fiber, the method comprising subjecting the stabilized fiber according to  claim 11  to a carbonization treatment.