Patent GB-1160368-A (GB)
Title: A New Method of Manufacturing Acrylic Filaments and Acrylic Filaments Made thereby.
IPC: D01F6/18
Filed: 1966-10-19
Abstract: 1,160,368. Wet spinning polyacrylonitrile. TOHO BESLON K.K. 19 Oct., 1966 [20 Oct., 1965; 6 Jan., 1966], No. 46655/66. Heading B5B. A solution of an acrylic polymer containing at least 85% by weight of polyacrylonitrile in an aqueous concentrated solution of one or more salts is wet spun into an aqueous coagulating bath and the resulting aquagel filaments are washed with water while in the aquagel condition until they are free of the spinning solution salt or salts. The filaments while still in the unoriented aquagel condition are then contacted with an aqueous emulsion of the oil-in-water type containing one or more surfactants under such conditions that the individual filaments absorb at least 1À5% of the surfactant or surfactants based on the weight of the resultant dried filaments. The filaments are then completely or partially dried, heat-stretched and finally heat-set. The polymer solvent may be an aqueous 55-65% by weight solution of zinc chloride alone or of zinc chloride and a chloride of an alkali metal or an alkaline earth metal. The heat-stretching of the treated filaments may be effected at a stretch ratio of over 4: 1 at a temperature between 100 and 180‹ C. and the subsequent heat-setting may be effected in air or in steam at a temperature above 150‹ C. The surfactant may be cationic and selected from the group alkyl amine acetate, alkyl pyridinium chloride, alkyl trimethyl ammonium chloride, N-alkyl-N-ethyl morpholinum ethosulphate, a diethanolamine alkyl ester or its neutralization compound, bis N,N<SP>1</SP>-ethyl aminoethyl alkyl amide, and alkyl dimethyl benzyl ammonium chloride, the alkyl radical of these compounds preferably having 5 to 20 carbon atoms. The surfactant may be anionic and selected from the group sodium alkyl sulphate, polyoxyethylene alkyl sulphate, alkyl phosphate, sodium dialkyl sulphosuccinate, sodium alkyl-N-methyl tauride and N-methyl alkyl glycine, the alkyl radical of these compounds preferably having 5 to 20 carbon atoms. The surfactant may be non-ionic and may be a polyoxyethylene alkyl ether, a polyoxyethylene alkyl-phenol ether, apolyoxyethylene alkyl ester, amine or amide, a polyoxyethylene alkylamino-amide sorbitan mono-alkylate, a glycerol mono-alkylate or a condensate of polyoxyethylene with polyoxypropylene, the alkyl radical of these compounds preferably having 5 to 20 carbon atoms. The surfactant may be amphoteric and may be N- alkyl, N-dimethyl betaine or 1-hydroxyethylene-2-alkyl-2-imidazoline, the alkyl radical of these compounds preferably having 5 to 20 carbon atoms. In the conventional treatment of polyacrylic filaments with aqueous emulsions of surfactant softening and lubricating agents, the emulsion is applied to the filaments after they have been heat stretched and heat set. Most of the agent then adheres to the surface of the filament, constitutes only 0À2 to 0À6% by weight of the dried filament and can be dissolved off the filament with a hot mixture of ethyl alcohol and benzene. In the process of the present invention most of the agent penetrates into the interior of the filament and cannot be removed by contacting the filament with the above solvent.