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US 5,667,743 AGranted
Wet spinning process for aramid polymer containing salts
AssigneeE. I. Du Pont de Nemours and Company
InventorsTsung-Ming Tai, David J. Rodini, James C. Masson, Richard L. Leonard
Life of this patent
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Abstract
A process for wet spinning a meta-aramid polymer solutions having a salt content of at least 3 percent by weight produces a one step, fully wet drawable fiber that has desirable physical properties without subjecting the fiber to hot stretching.
Claims7
A process for wet spinning a meta-aramid polymer from a solvent spinning solution containing concentrations of polymer, solvent, water and at least 3% by weight salt comprising the steps of:
- (a) coagulating the polymer into a fiber in an aqueous coagulation solution containing a mixture of salt and solvent such that the concentration of the solvent is from about 15 to 25% by weight of the coagulation solution and the concentration of the salt is from about 30% to 45% by weight of the coagulation solution and wherein the coagulation solution is maintained at a temperature from about 90.degree. to 125.degree. C.;
- (b) removing the fiber from the coagulation solution and contacting it with an aqueous conditioning solution containing a mixture of solvent and salt such that the concentrations of solvent, salt and water are defined by the area shown in FIG. 1 as bounded by coordinates W, X, Y and Z and wherein the conditioning solution is maintained at a temperature of from about 20.degree. to 60.degree. C.;
- (c) drawing the fiber in an aqueous drawing solution having a concentration of solvent of from 10 to 50% by weight of the drawing solution and a concentration of salt of from 1 to 15% by weight of the drawing solution;
- (d) washing the fiber with water;
- and
- (e) drying the fiber.
3 more elements
Dependencies are inferred from the claim text.