| 摘要 |
Fibres are made from acrylonitrile by blending a polymer having at least 85 per cent. by weight in the polymer molecule of acrylonitrile with between 30 per cent. and 60 per cent. by weight of a plasticizer, extruding the blend by the application of heat and pressure into an inert atmosphere, cooling the extruded material and pulling away the solidified extruded fibre at a velocity of at least 30 times the jet velocity of extrusion. The extrusion temperature may be between 140 DEG C. and 230 DEG C. and the pressure between 50 and 11,000 pounds per square inch. The fibres may be extruded into air at room temperature and after being drawn away the solvent is removed by washing with water, acetone, alcohol, ether, or a chlorinated hydrocarbon. The velocity of the solidified fibre may be between 1,000 and 7,000 yards per minute. The solidified fibre may be relaxed and allowed to shrink at a temperature between 90 DEG C. and 200 DEG C. in air, water, steam, glycol, glycerine or mineral oil to obtain a crimped fibre. From the extrusion jet to the take up means the fibre may travel between 20 and 30 inches. Cold air may be blown on to the fibre to assist solidification. The melt may be passed through a coarse sand filter prior to spinning. The fibre may be cut into staple length prior to extraction of the solvent and relaxation of the fibre to obtain crimp. The fibres may have a circular, "dog-boned" or cruciform cross section. The polymer may be a co-polymer of acrylonitrile with 2-vinyl pyridine, N-acetyl morpholine, methacrylic acid, methyl acrylate, styrene, methacrylonitrile, methyl vinyl ketone, vinyl chloride, vinyl fluoride, vinylidene chloride, vinylidene fluoride, vinylidene chlorofluoride, vinylidene cyanide, butadiene, vinyl pyridine acrylamide, a N-mono-or disubstituted amide or a vinyl ether. The plasticizer may be tetramethylene cyclic sulphone, ethylene cyclic carbonate, N.N dimethyl formamide, N-acetyl morpholine, ethylene sulphite, N.N. dimethyl acetamide, N-methyl N-cyanoethyl formamide, N.N-dimethyl hydroxyacetamide, N.N- dimethyl methoxyacetamide, N-formyl hexamethylene imine, p-phenylene diamine, m- and pnitrophenol, succinonitrile, glycolonitrile, succinic anhydride, diglycolic anhydride, N.N1 diformyl piperazine, or a mixture of butyrolactone and ethylene cyclic carbonate. U.S.A. Specifications 2,404,714 to 2,404,727, inclusive, 2,436,926, 2,486,241, 2,491,471 and 2,546,238, are referred to. |
