Mitsubishi Rayon Company, Limited

Kanji Yoshida

Kensuke Kamada

Shunsuke Minami

Takashi Setsuie

Takeji Otani

An acrylic fiber precursor for high performance carbon fibers free of defects which comprises an acrylonitrile polymer containing at least 90% by weight of acrylonitrile and has a surface roughness of 2.0 to 3.0 with dense inner structure. from a solution comprising 24 to 27.5% of the acrylonitrile polymer is dry-jet wet spun into a coagulation bath consisting essentially of dimethylformamide or dimethylacetamide and having a bath temperature of 5.degree. to 25.degree. C.Carbon fibers obtained by carbonizing these precursor acrylic fibers have no fusion bonding or agglutination of filaments and exhibit high performance.

Method for producing acrylic fiber precursors

There are disclosed porous polypropylene hollow filaments which have a surrounding wall portion of less than 60 .mu., preferably 40 .mu. in thickness which contains many fine holes communicating with each other, distribution curve of radius of said fine holes having at least one maximum points within the range of 200-1200 A. The method for producing said porous polypropylene hollow filaments is also disclosed.

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Ohtake, Japan

Kanji Yoshida