Japan Exlan Company Limited

Shiro Kawasaki

Noriyuki Kohara

Mamoru Ashida

The present invention offers a safe and economic method for manufacturing chitosan fiber wherein an aqueous solution of sodium thiocyanate is used. In the present invention, chitosan having a degree of deacetylation of not less than 60% is dissolved in an aqueous solution of not less than 44% by weight of sodium thiocyanate and the resulting spinning solution is subjected to a wet spinning to manufacture a chitosan fiber.

Method for manufacturing chitosan fiber

This invention offers the porous fiber in which the porous form of the fiber is with an excellent durability to heat and accordingly can afford the fiber products with a shape-retaining ability. Porous acrylonitrile fiber comprising the polymers containing not less than 95% by weight of acrylonitrile in a bonded form whereby the pores in the fiber constituting the porous structure are connected each other and are communicated with the fiber surface and, in addition, having a specific decreasing rate in the average pore diameter due to an introduction of a crosslinking structure thereinto. It is possible to offer a porous acrylonitrile fiber which has a porous structure wherein the micropores in the fiber are connected each other and are communicated with the fiber surface and also exhibits an excellent retaining ability of the shape of the fiber.

Porous acrylonitrile polymer fiber

A safe, energy-Saving process for recovering (or purifying) thiocyanate from a large amount of waste liquid (or thiocyanate-containing aqueous solution) by the aid of a reverse osmosis membrane whose sodium chloride rejection is from 10% to 70%. The process performs recovery without decreasing the concentration of thiocyanate in feed.

Process for recovering thiocyanate

A process for removing colored components from a recovered inorganic solvent of polyacrylonitrile, without an appreciable decrease in the concentration of active components, using a reverse osmosis membrane whose NaCl rejection is in the range of 10% to 97%, under a permeation pressure lower than 20 kg/cm.sup.2.

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Okayama, Japan

Shiro Kawasaki