Toho Beslon Co., Ltd.

The Japan Tobacco Salt Public Corporation

Toho Rayon Co., Ltd.

Toho Belson Co., Ltd.

Minoru Hirai

Kazuo Izumi

Shigeru Ikegami

Masatoshi Yoshida

Kazuo Maeda

Kenji Shimazaki

Yuriko Anzai

Katsumi Nakama

Hideaki Fukuizumi

Kenji Niijima

Katsuichi Noguchi

Masakazu Ataka

Yoh-ichi Maeda

Yoshihumi Kawakatsu

A carbon fiber chopped strands suitable for use in production of a composite with a matrix material, which have a circular or elliptical cross-section, wherein carbon fiber filaments are bundled by a sizing agent in an amount of from 1 to 10% by weight based on the chopped strand, and which have denseness of from 0.4 to 0.9 according to the formula below: ##EQU1## where D denotes the average diameter of the chopped strands, d denotes the average diameter of filaments constituting the chopped strand and N denotes the number of the filaments, and a method for production thereof by impregnating a carbon fiber strand with a sizing agent in an amount of from 1 to 10% by weight based on the total weight of the chopped strand to form a sized strand, and then cutting the sized strand, thereby giving the denseness of from 0.4 to 0.9 according to the formula (1).

Carbon fiber chopped strands and method of production thereof

A method for manufacturing activated carbon fibers is disclosed. The method is comprised of the steps of:

Method for manufacture of activated carbon fiber

A fibrous activated carbon with a metal chelate compound supported thereon which is suitable for removal of toxic substances in gas. This activated carbon is obtained by attaching a solution or dispersion of the metal chelate compound onto the fibrous activated carbon followed by drying. Contacting the activated carbon with a toxic substance-containing gas provides very efficient removal of the toxic substance from the gas.

Fibrous activated carbon with metal chelate compound supported thereon,

A fibrous activated carbon having high adsorptivity and excellent mechanical properties is produced by preoxidizing an acrylonitrile-based fiber containing a specific amount of an iron compound at a specific initial heat-treatment temperature and then activating.

Process for the production of fibrous activated carbon

A process for producing activated carbon fibers of high adsorption capacity which comprises oxidizing an acrylonitrile based fiber, wherein the acrylonitrile based fiber is a homopolymer of acrylonitrile, a copolymer containing about 60% by weight or more of acrylonitrile, or a mixture of polymers such that about 60% by weight or more of acrylonitrile is present in the mixture, in an oxidizing atmosphere at a temperature of about 200.degree. C. to about 300.degree. C. while applying a tension to the fiber until the amount of bonded oxygen reaches about 65% to about 95% of the saturated amount of bonded oxygen of the fiber, wherein the tension applied is such that the shrinkage of the fiber during oxidation reaches about 70% to about 90% of the degree of free shrinkage at the same temperature, and then activating the fiber.

Process for production of activated carbon fibers

A process for producing activated carbon fibers comprising subjecting an acrylonitrile based fiber to oxidation processing in an oxidizing atmosphere at a temperature of about 200.degree. C. to about 300.degree. C. while applying a tension to the fiber until the amount of bonded oxygen reaches about 50% to about 90% of the saturated amount of bonded oxygen followed by activation processing.

A tobacco smoke filter capable of selectively removing irritating materials and unpleasant bitter components from tobacco smoke and containing as a filter element nitrogen-containing activated carbon fibers produced by oxidizing acrylonitrile polymer fibers and then activating the oxidized fibers.

Growing community of inventors

Shizuoka, Japan

Minoru Hirai