| 摘要 |
Filaments, films &c. of acrylonitrile homopolymers and copolymers containing not less than 85% acrylonitrile by weight are produced by extruding a solution of the polymer in nitric acid of at least 69% concentration by weight, the solution having at the temperature of extrusion a viscosity of more than 1,000 poises, into a first coagulating bath of nitric acid of 47 to 50% concentration by weight, stretching the filaments &c. in this bath and transferring them to a second coagulating bath of nitric acid sufficiently dilute to complete the coagulation of the filaments &c., e.g. of less than 35% concentration, washing the filaments &c., stretching the wet filaments &c. at an elevated temperature to orient them and drying them. The filaments &c. may be stretched at a stretch ratio of 13:1 in the first coagulating bath p and at a low stretch ratio in the second coagulating bath. The temperature of the solution being extruded may be within the range of +10 DEG C. to -10 DEG C. and the first and second coagulating baths may be maintained at below 10 DEG C.
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