Abstract: A moisture absorbing hygroscopic fiber having high whiteness, characterized in that (1) acrylic fiber comprising acrylonitrile copolymer where a (meth)acrylate compound as a copolymer component is less than 5% by weight is treated with a hydrazine compound whereby introduction of crosslink and increase in nitrogen content to an extent of 1.0 about 10.0% by weight is carried out, (2) treatment with an aqueous solution of alkaline metal salt is carried out whereby carboxyl group of a metal salt type by which CN group is hydrolyzed is produced in an amount of 4.0 about 10.0 meq/g and (3) a reducing treatment by a reduction treatment agent selected from a group consisting of hydrosulfite, thiosulfate, sulfite, nitrite, thiourea dioxide, and ascorbate compound is carried out.

Abstract: An object of the present invention is to provide a discoloration inhibitor for metals, for protecting metal artifacts, such as those made of silver, copper, and nickel, or their alloys, from discoloration due to sulfur-containing gases such as sulfur oxide (SOx), mercaptans, and hydrogen sulfide, for example, during display or storage of the metal artifacts. A discoloration inhibitor for metals comprising: a fiber having a crosslinking structure and containing carboxyl groups therein, at least part of said carboxyl groups being present as a salt of an alkali metal, an alkali earth metal or ammonia; and fine particles of a metal and/or a metal compound substantially insoluble in water and reactive with a sulfur-containing compound dispersed in said fiber is disclosed.

Abstract: A method for the manufacture of moisture absorbing fiber having high whiteness, characterized in that an acrylic fiber comprising acrylonitrile polymer where a (meth)acrylate compound as a copolymer component is less than 5% by weight is subjected to crosslink introduction treatment using a hydrazine compound, to hydrolysis and to reducing treatment.

Abstract: An object of the present invention is to provide a discoloration inhibitor for metals, for protecting metal artifacts, such as those made of silver, copper, and nickel, or their alloys, from discoloration due to sulfur-containing gases such as sulfur oxide (SOx), mercaptans, and hydrogen sulfide, for example, during display or storage of the metal artifacts. A discoloration inhibitor for metals comprising: a fiber having a crosslinking structure and containing carboxyl groups therein, at least part of said carboxyl groups being present as a salt of an alkali metal, an alkali earth metal or ammonia; and fine particles of a metal and/or a metal compound substantially insoluble in water and reactive with a sulfur-containing compound dispersed in said fiber is disclosed.

Abstract: Disclosed are a hot-melting acrylonitrile (AN) polymer composition comprising a non-volatile component modified from AN alone or a AN monomer composition through chemical reaction, an AN polymer and water, a method for producing the composition, and a method for producing a shaped article of AN polymer by melting the composition under heat followed by shaping the melt. The composition and the shaped article do not contain toxic AN and AN monomer mixture.

Abstract: A process for producing a homogeneous phase melt of polyacrylonitrile suitable for extrusion molding and melt spinning, by the steps of preparing polymer/water crumb containing 30-60 wt % of polyacrylonitrile and dewatering the crumb in a molten state with stirring at temperatures above 140.degree. C. and at pressures above autogenous pressure until the concentration of the polymer in the crumb exceeds 70% by weight.

Abstract: Saturated or superheated steam, or an inert gas, or a combination thereof is introduced into a gas phase above a molten acrylonitrile polymer in a vessel having a stirrer, while the polymer has a temperature of at least 120.degree. C. and a pressure at least equal to its autogenous pressure. Any unreacted acrylonitrile monomer, or both any such monomer and any acrylonitrile monomer or water used as a plasticizer are removed by evaporation from the vessel.

Abstract: Disclosed herein is an acrylic fibrous material capable of absorbing and evaporating water stably and rapidly without requiring any water-absorbing material. It finds use as the water-absorbing and -evaporating member of a humidity controller. Disclosed also herein is a humidity controller provided with such an acrylic fibrous material.

Abstract: 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.

Abstract: 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.