| 摘要 |
PROBLEM TO BE SOLVED: To provide a flame resistant fiber sheet precursor for producing a flame resistant fiber sheet having excellent flame resistance, heat resistance, flame retardancy, chemical resistance, flexibility and light weight, exhibiting high-precision filtration performance and generating little fine fiber powder, especially a flame resistant fiber sheet for air filter. SOLUTION: The flame resistant fiber sheet precursor is a polyacrylonitrile fiber sheet composed of a nonwoven fabric of a polyacrylonitrile copolymer obtained by the copolymerization of a monomer having carboxylic acid group ester or an acrylamide monomer and containing ultrafine polyacrylonitrile fiber having an average diameter of <1μm. The flame resistant fiber sheet is produced by heat-treating the precursor in an oxidizing atmosphere at 150-350°C for 1-240 min. COPYRIGHT: (C)2007,JPO&INPIT
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