| 摘要 |
Regenerated cellulose filaments which crimp when wetted are made by extruding a continuous stream of viscose into a coagulating bath and injecting supplementary amounts of viscose into the stream at predetermined intervals of time so as to form filaments of varying cross section, the viscose containing 7,0-8,6% by weight of cellulose, 6,0-8,5% by weight of sodium hydroxide and 35-40% of carbon bisulphide, based on the alpha cellulose in the viscose, and having a sodium chloride salt test of 3-10 and a ball fall viscosity of 10-150 seconds and the coagulating bath containing 6,6-7,7% by weight of sulphuric acid, 1-1,5% by weight of zinc sulphate and 16-20% by weight of sodium sulphate and having a temperature of 50-70 DEG C.; the filaments are withdrawn from the coagulating bath as a multifilament yarn, which is stretched while immersed in a hot stretch bath consisting of an aqueous solution of acid and salts which is more dilute and at a higher temperature than the coagulating bath, and the stretched yarn is subjected to a series of wet processing steps, stretched a second time between the hot stretch bath and the wet processing, stretched a third time during the wet processing, and then dried without loss of tension and collected. The yarns thus produced have, when wetted, spaced cross-sections of strong crimp alternating with spaced cross-sections of lesser crimp. Yarns thus produced are suitable for the production of pile fabrics such as tufted carpets. U.S.A. Specifications 2,386,173, 2,517,694 and 2,572,936 are referred to.
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