GB438587A - Improvements in the manufacture of filaments and threads of cellulose acetate - Google Patents

Abstract

Continuous filaments of cellulose acetate and threads consisting of such filaments are subjected to a stretching operation in hot water under pressure at a temperature above 100 DEG C., e.g. 110, 120, 130 DEG C., or more. The <PICT:0438587/IV/1> pressure is that required to keep the water in the liquid state, and may be 10, 20, 30 or more pounds per square inch. The stretching operation may be carried out on the materials during the course of their travel from one point to another, e.g. a number of threads may be stretched simultaneously while running from one creel of bobbins to another. A suitable apparatus comprises a hot water chamber 4 provided with water supply pipe 9 and draw off pipe 10, pressure gauge 11, and steam heating coil 12. Catch trays 13 and 14 are provided at each end of the chamber. A number of threads 1 from a creel of bobbins 2 pass through a pair of nip rollers 3, and through orifices in the end plate 7. The threads on leaving the chamber through orifices in the opposite end plate 8 are drawn by means of a pair of nip rollers 5 and collected on a second creel of bobbins 6. The orifices in the end plates are sufficiently small to allow the pressure to be maintained. The stretched materials may be subjected to any desired after-treatments, e.g. treatments to cause shrinkage, as described in Specification 389,823, or to cause partial or substantially complete saponification. Specifications 177,868, 179,234, 316,521, 318,468, [all in Class 2 (ii)], 340,324, 340,325, 340,436, 340,437, 343,062, 370,430, 402,104, 402,105, 402,106, and 403,106 also are referred to.