Abstract: 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.

Abstract: A process for producing acrylonitrile-based copolymers for carbon fibers is described, which comprises producing substantially metal-free acrylonitrile-based copolymers containing as essential components at least 95% by weight of acrylonitrile and from 0.5 to 3% by weight of a carboxyl group-containing polymerizable unsaturated monomer, at least 20% of the carboxyl groups being substituted with ammonium ions, in the presence of a redox polymerization initiator comprising ammonium persulfate and ammonium sulfite and, thereafter, spinning the acrylonitrile-based copolymer. The present invention permits production of acrylonitrile-based copolymers free of metal impurities responsible for the formation of defects in the ultimate carbon fibers. High performance carbon fibers can be produced without the need of any additional steps.

Abstract: There is disclosed a method for making high strength carbon fibers which comprises carbonizing acrylic fibers applied with an aqueous dispersion of a silicone compound represented by the following general formula [I] dispersed with an emulsifier represented by the following general formula [II], the total amount of the silicone compound and the emulsifier being 0.01 to 10.0% by weight (owf) and the weight ratio of the emulsifier to the silicone compound being 0.05 to 0.4: ##STR1## (where the symbols are as defined hereinbefore).

Abstract: A suede-like sheet material characterized by being formed of a base cloth and ultrafine fibers of a denier less than 0.5 per filament, said ultrafine fibers being entangled with each other and covering at least one surface of the base cloth, wherein a portion of said ultrafine fibers is stuffed into the gaps in the network of the base cloth, at least a portion of said ultrafine fibers being entangled with the component fibers of the base cloth, and said base cloth and ultrafine fibers being substantially integrated with each other.

Abstract: A suede-like sheet material characterized by being formed of a base cloth and ultrafine fibers of a denier less than 0.5 per filament, said ultrafine fibers being entangled with each other and covering at least one surface of the base cloth, wherein a portion of said ultrafine fibers is stuffed into the gaps in the network of the base cloth, at least a portion of said ultrafine fibers being entangled with the component fibers of the base cloth, and said base cloth and ultrafine fibers being substantially integrated with each other.

Abstract: An apparatus for producing composite structure fibers is disclosed which includes an upper distribution plate provided with plural slits for making at least two spinning components into independent thin layer streams, a lower distribution plate provided with plural fine holes for dividing each of said thin layer streams into plural fine capillary streams independent from each other and a spinneret plate provided with a bundling space and extrusion orifices for bundling said previously divided fine capillary streams and extruding them into filaments, said upper distribution plate, lower distribution plate and spinneret plate being piled up in this order.