Process for producing wholly aromatic polyamide fibers
AssigneeTeitin Limited
InventorsKeiji Kouzai, Yutaka Tabe, Eiji Masunaga, Kichiro Matsuda
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AssigneeTeitin Limited
InventorsKeiji Kouzai, Yutaka Tabe, Eiji Masunaga, Kichiro Matsuda
Estimating the term…
A process for producing wholly aromatic polyamide fibers by extruding a spinning solution of a wholly aromatic polyamide in an amide solvent into an aqueous coagulating bath containing inorganic salts, said process comprising feeding an aqueous coagulating liquid containing calcium chloride and having an amide solvent concentration of not more than 3% by weight to the vicinity of a spinneret, flowing the coagulating liquid in said bath at an average velocity not more than 0.1 time the velocity of yarn take-up in the yarn advancing direction, discharging the coagulating liquid having an amide solvent concentration of not less than 4% by weight from said bath, treating the coagulating bath with an organic solvent consisting substantially of methylene chloride, and extracting and recovering the amide solvent from the coagulating liquid.
A process for producing wholly aromatic polyamide filaments having at least 75 mol% of the recurring units being derived from m-phenylene isophthalamide, said process comprising extruding a spinning solution of said wholly aromatic polyamide in an amide solvent having a polymer concentration of 15 to 30 % by weight and being free of inorganic salts through a spinneret into an aqueous coagulating bath containing a total concentration of calcium chloride, magnesium chloride, calcium nitrate and zinc chloride of at least 35% by weight of liquid and a concentration of calcium chloride of at least 20% by weight of liquid and having an amide solvent concentration of not more than 3% by weight of liquid to the vicinity of said spinneret, said amide solvent essentially consisting of N-methyl-2-pyrrolidone, taking-up the coagulated filaments from the lower portion to the upper portion of the coagulating bath, flowing the coagulating liquid in said bath at an average velocity from 0.04 to 0.1 times the velocity of filament take-up in the filament advancing direction, discharging the coagulating liquid having a specific gravity, measured at 60.degree. C of at least 1.36 and an amide solvent concentration of not less than 4% by weight from said bath, extracting N-methyl-2-pyrrolidone from the discharged coagulating liquid with an organic solvent consisting essentially of methylene chloride, and recovering the N-methyl-2-pyrrolidene from the organic solvent.
Dependencies are inferred from the claim text.