| 摘要 |
PROBLEM TO BE SOLVED: To obtain a large tow precursor intended for productivity improvement and capable of giving carbon fiber retaining its mechanical strength by converging respective subtows through crimping to increase the number of filaments, and to provide a method for producing the above precursor. SOLUTION: This large tow precursor for carbon fiber production is obtained by using an acrylic copolymer as the raw material and through a process comprising spinning-washing with water-1st oiling-drying-drawing-relaxation-2nd oiling-crimping-drying. This large-tow precursor consists of crimped filaments each >=80% in degree of orientation determined by wide angle X-ray diffractometry, is in a sheet-like form 60,000-3,000,000 denier in total fineness assembled with 3-30 subtows each 20,000-100,000 in the number of acrylic filaments each 0.5-3 denier in fineness, and divisible into subtow units. The other objective carbon fiber produced by using the above large tow precursor has a mechanical strength of >=300 kfg/mm2 and <200μg/ft in fluffing levels.
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