Abstract: A process for purifying an acrylic fiber solvent solution which comprises (1) feeding an acrylic fiber solvent containing impurities or an aqueous solution thereof to a packed layer of a polymer consisting of one or more kinds of ester type monomers containing at least one polymerizable double bond and at least one ethylene oxide unit per molecule or a polymer consisting of such monomer(s) and one or more kinds of monomers containing at least one polymerizable double bond for one molecule, to cause said layer to catch the impurities and fiber solvent, (2) passing an eluent through said packed layer thus eluting the impurities together with the eluent, and (3) passing a further amount of the eluent through the packed layer thereby separating an eluate containing the fiber solvent.

Abstract: Process for producing an acrylonitrile polymer in a substantially melted state by polymerizing a monomer mixture composed mainly of acrylonitrile in the presence of water under a pressure above the autogenous pressure at a temperature of from 80.degree. to 120.degree. C so as to attain a polymerization rate of at least 45%.

Abstract: Method for opening a high-density packed column in liquid chromatography wherein a large number of components in a solution are separated by means of a column in which a swollen gel is packed at a high density. The improvement involves passing air through the column while heating the column to a temperature above at least 40.degree. C. to shrink the volume of the packed column, and then opening the column. According to this process, there is no loss in the expensive gel nor contamination thereof and yet it's operating efficiency is greatly improved.

Abstract: The present invention relates to a process for the polymerization of acrylonitrile or a monomer mixture containing acrylonitrile as a main component and at least one other ethylenically unsaturated compound, characterized in that the polymerization is conducted at a temperature above 120.degree. C. under a pressure above the vapor pressure generated in the polymerization system under the polymerization conditions in a system in which water is present in a range of 3 to 50 percent by weight based on the total weight of the monomer(s) and water to produce an acrylonitrile polymer in a substantially molten state. The polymers produced according to the above process have the advantage of being able to be directly shaped by extrusion without the need of solvents.

Abstract: In a process for the production of flame retardant acrylic synthetic fibers by mixing a spinning solution of a acrylonitrile polymer with an emulsion of a polymer of a vinyl halide and/or vinylidene halide, and wet-spinning the resulting mixed solution, the improvement which comprises using, as said emulsion, an emulsion obtained by polymerizing a vinyl halide and/or vinylidene halide in an aqueous medium in the presence of certain water-soluble polymer.

Abstract: A process for producing a carbon fiber having high tensile strength and high modulus of elasticity which comprises heat-treating an acrylonitrile fiber impregnated with at least one compound selected from specific primary amines and/or quaternary ammonium salts so that an acrylic fiber which is partly insoluble in a concentrated aqueous solution of sodium thiocyanate is obtained; thermally stabilizing said partly insoluble acrylic fiber; and then carbonizing said thermally stabilized fiber.

Abstract: Colloidal antimony oxide is continuously produced by passing an aqueous dispersion containing antimony trioxide and hydrogen peroxide through a heated tube-type reactor.

Abstract: Process for imparting an animal hairlike hand to acrylic fibers by mixing a silicone resin and a polyoxyethylene alkylphenyl phosphate while adding water thereto to form an emulsion of weak acidity, applying the emulsion to swollen gelly acrylic fibers, drying the resultant fibers and applying a spinning oil to the dried fibers.

Abstract: Carbon fibers are produced by continuously heat-treating acrylonitrile fibers up to the crystal collapse starting temperature of said fibers while maintaining said fibers under a fixed length or tension in an oxidizing atmosphere, then sufficiently thermally stabilizing fibers by further subsequently continuously heat-treating them in a temperature range gradually elevated up to a fixed temperature in a range of from a temperature about 20.degree. C lower than the deterioration starting temperature of said fibers to a temperature about 20.degree. C higher than said deterioration starting temperature in an oxidizing atmosphere. The thus sufficiently thermally stabilized fibers are treated with a reducing liquid and subsequently carbonized or graphitized in a non-oxidizing atmosphere or under a vacuum.

Abstract: Carbon fibers having excellent properties are produced by a process which comprises thermal-stabilizing and carbonizing acrylonitrile fibers containing certain aminosiloxanes.

Abstract: There is provided a process for preparing a stable polymer emulsion characterized by polymerizing a radical-polymerizable monomer having unsaturated bond by using a water-soluble catalyst in an aqueous medium and in the presence of a water-soluble polymer containing chemically bonded monomeric units of methacrylic acid or its salt and monomeric units of ethylenically unsaturated sulfonic acid or its salt, said polymerization being conducted at a pH of 4 or lower.

Abstract: Carbon fibers having excellent physical properties are produced by a process which comprises heating acrylonitrile copolymer fibers made from an acrylonitrile copolymer produced by copolymerizing at least 80 mole % acrylonitrile and 0.3 to 6 mole % of an unsaturated monomer containing a carboxyl group and in which 0.1 to 15% of the terminal hydrogens of said carboxyl groups have been replaced with alkali metal cations or ammonium ions.

Abstract: Improved carbon fibers (including graphite fibers) are produced by drying acrylic fibers in a water-swollen state spun from an inorganic solvent solution of an acrylonitrile homopolymer or copolymer containing at least 85 mol % acrylonitrile and having an orientation degree of at least 50% and a water content of 5 to 150%. The drying step is carried out at a temperature below 70.degree. C to reduce the water content in said fibers to below 4%. The dried fibers are then heated to form the improved carbon fibers.

Abstract: A method of producing synthetic resin spinnerettes. Vertically extending synthetic filaments are mounted on a frame structure and placed in a mold. A thermoplastic or themosetting resin is poured into the mold and allowed to set. The molded body is removed from the mold and the filaments are removed therefrom to leave orifices.

Abstract: The present invention relates to a process for producing high shrinking acrylic fibers which have excellent antipilling properties and dyeing characteristics. This process involves dissolving an acrylonitrile polymer in an inorganic solvent to prepare a spinning solution containing the inorganic solvent in a concentration of 40-70%, subjecting the spinning solution to a wet-spinning by extruding through spinnerette orifices into two coagulating baths, while maintaining the linear velocity ratio of free extrusion at 1 or higher and maintaining a jet stretch ratio of 1.5 or higher, stretching the formed swollen gel fibers to 3-7 times the length in hot water or in a heated steam medium at 80.degree.-120.degree.C, drying the stretched fibers, then subjecting the fibers to a secondary stretch of 1.05 to 1.60 times the length, wherein the first coagulating bath has an inorganic solvent concentration of 50-70% of that in the spinning solution.

Abstract: The present invention relates to a process for producing an anti-pilling acrylic fiber which has excellent level dyeing properties. This process involves dissolving an acrylonitrile in an inorganic solvent to prepare a spinning solution, wherein the inorganic solvent in the spinning solution is 40-70%, subjecting the spinning solution to wet-spinning by extrusion through spinneret orifices into a coagulation bath containing an inorganic solvent in an amount of 50-70% of that in the spinning solution, while maintaining the linear velocity ratio of free extrusion at 1 or higher and the jet stretch ratio 1.5 or higher, stretching the formed gel fibers 3-7 times the length in hot water or in a heated steam medium at 80.degree.-120.degree.C, drying the stretched fibers and then subjecting the fibers to a relaxation treatment in a hot air current at a temperature of 150.degree.C or lower or in a wet heat atmosphere at a temperature of 120.degree.C or lower.

Abstract: Acrylic synthetic fibers having an interfiber entanglement coefficient of 10-40, an interfiber entangling force after hot-water treatment of not greater than 50 mg and a specific type of silicone resin deposited on the surfaces of the fibers.

Abstract: A process for producing carbon fibers which comprises (a) treating preoxidized fibers produced from an acrylonitrile fiber with a reducing liquid containing a specific compound and (b) thereafter carbonizing or graphitizing the treated fibers at a temperature above 800.degree. C. The thus-obtained carbon or graphite fibers have a high tensile strength and a high modulus of elasticity.