Claims
- 1. 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.
- 2. The process of claim 1 wherein the spinneret has at least 5000 holes.
- 3. The process of claim 1 wherein said aqueous coagulating liquid is an aqueous solution of calcium chloride in a concentration of at least 35%.
- 4. The process of claim 1 wherein the temperature of the aqueous coagulating liquid is at least 60.degree. C.
- 5. The process of claim 1 wherein the coagulating liquid from which a part or whole of the amide solvent has been removed by extraction with methylene chloride is recycled to the coagulating bath.
- 6. The process of claim 1 wherein the N-methyl-2-pyrrolidone solvent is recovered from the methylene chloride by evaporation and distillation, and is used in the preparation of the spinning solution.
Priority Claims (2)
Number |
Date |
Country |
Kind |
47-48521 |
May 1972 |
JA |
|
47-58264 |
Jun 1972 |
JA |
|
Parent Case Info
This is a continuation of application Ser. No. 360,535, filed May. 15, 1973, now abandoned.
US Referenced Citations (8)
Continuations (1)
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Number |
Date |
Country |
Parent |
360535 |
May 1973 |
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