Abstract: The invention is concerned with a method of producing in-line dyed fibers, in a gel state, characterized in that it essentially consists of extruding the spinning dope in a coagulum bath, stretching the resulting filaments, scrubbing said filaments to remove residual solvent, passing the resulting filament tow through a dyeing bath at an overall rate in excess of 4 cm.sup.3 bath per second per square centimeter of tow surface area. The overall rate, being preferably in the 4 to 10 cm.sup.3 /sec per cm.sup.2 range, is achieved by means of crossflows to the forward advance direction of said tow, and alternately directed to and from said tow, the tow residence time in the dyeing bath being no longer than 5 seconds. The tow is then subjected to a dye fixing heat treatment, and is then scrubbed, finished, and dried. The method is particularly suitable for use with substantially acrylic and modacrylic fibers.

Abstract: Modacrylic fibres from acrylonitrile, vinylidene chloride, and a sulphonated comonomer, having reduced inflammability and high glossiness and dye yield are prepared by wet spinning a polyblend obtained by mixing two binary copolymers, the first from acrylonitrile and the sulphonated comonomer, and the second from acrylonitrile and vinylidene chloride. As the sulphonated comonomer, a significantly homopolymerizable monomer is used, viz. a monomer which homopolymerizes with a conversion of at least 30-40% by weight, in the presence of azobisisobutyronitrile catalyst, under given standard reaction conditions. Preferred sulphonated monomers are acid or salts of the acrylamidoalkanesulphonic series. The spinning dope is a polyblend solution in an organic solvent chosen among dimethylformamide, dimethylacetamide, and dimethylsulphoxide, mixed with water.

Abstract: A method for preparing flame-resisting modacrylic fibers containing pentaent antimony oxide is described wherein the antimony oxide is suspended in a mixture of water and an organic solvent selected from dimethylformamide and dimethylacetamide and the suspension is then mixed with the viscose solution of the modacrylic polymeric material to be spun. The process yield high luster, flame-resisting modacrylic fibre of the "L.O.I. uprated" type.

Abstract: Modacrylic fibers having high retraction, reduced inflammability and high glossiness, prepared by wet spinning a solution, in an organic spinning solvent miscible with water, of a mixture of copolymers from acrylonitrile, vinylidene chloride, at least a vinyl ester and at least an unsaturated monomer containing at least a sulphonic group, the acrylonitrile units being from 50% to 85% by weight and the vinyl ester units from 3% to 6% by weight; hot drawing the coagulated fiber in a mixture of water and spinning solvent; drying the fiber in hot air while leaving it free concurrently to contract; and subsequently further hot drawing it in air.

Abstract: Textile fibers having reduced inflammability and high luster, constituted copolymers of acrylonitrile, vinylidene chloride and a significantly homopolymerizable sulphonic comonomer are described. Significantly homopolymerizable comonomers are defined as monomers which homopolymerize with a conversion above 30.degree.-40.degree. under standard conditions set forth in the specification. A preferred class of such comonomers are the derivatives of acrylamidoalkanesulphonic acids, e.g. 2-acrylamido-2-methylpropane-sodium sulphonate. The fibers are spun from spinning dopes containing said copolymers in solution in organic solvent miscible with water and less than 4% of water. Said spinning dopes can be obtained by preparing a binary copolymer of acrylonitrile and the sulphonic monomer, in solution in the solvent, mixing the solution with a solution of acrylonitrile and vinylidene monomers in the same solvent, and subjecting the mixture to copolymerization.

Abstract: Modacrylic fibres from acrylonitrile, vinylidene chloride, and a sulphona comonomer, having reduced inflammability and high glossiness and dye yield are prepared by wet spinnning a polybend obtained by mixing two binary copolymers, the first from acrylonitrile and the sulphonated comonomer, and the second from acrylonitrile and vinylidene chloride. As the sulphonated comonomer, a significantly homopolymerizable monomer is used, viz. a monomer which homopolymerizes with a conversion of at least 30-40% by weight, in the presence of azobisisobutyronitrile catalyst, under given standard reaction conditions. Preferred sulphonated monomers are acid or salts of the acrylamidoalkanesulphonic series. The spinning dope is a polyblend solution in an organic solvent chosen among dimethylformamide, dimethylacetamide, and dimethylsulphoxide, mixed with water.