GB438586A - Improvements in the manufacture of artificial threads, films or the like - Google Patents

Abstract

Filaments, threads, spun yarns, foils, films, and the like of cellulose acetate or other ester or ether of cellulose are subjected to a stretching operation in hot water at above 95 DEG C., but excluding water under pressure at a temperature above 100 DEG C. In the case of continuous filaments of a cellulose ester or ether (other <PICT:0438586/IV/1> than cellulose acetate) or threads consisting of such filaments, hot water under pressure at a temperature above 100 DEG C., may be employed. Spun yarns, films, and foils of cellulose acetate or other ester or ether of cellulose may be subjected to a stretching operation in hot water under pressure at a temperature above 100 DEG C. The operation may be carried out on the materials during the course of their travel from one point to another, for example, a number of threads may be stretched simultaneously while running from one creel of bobbins to another. For stretching threads and yarns, the apparatus described in Specification 438,587 may be used. A suitable apparatus for stretching ribbons comprises a hot water chamber 4 provided with hot 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 ribbon 1 from a roll 2 passes through a pair of nip rollers 3 and through a slit in the end plate 7. The ribbon leaves the chamber through a slit in the opposite end plate 8, is drawn by means of a pair of nip rollers 5, and collected on a second roll 6. In the case of films and foils the stretching may be longitudinal and/or lateral. 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. According to the Provisional Specifications, the required temperature of the water may be reached without the use of excess pressure or with lower excess pressure by dissolving suitable salts or sugars in the water. Sodium, potassium, and calcium chlorides, sodium and potassium sulphates, and potassium nitrate are specified. 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, 380,504, 380,505, 400,597, 402,104, 402,105, 402,106, 403,106; 424,683, 424,752, 424,830, and 424,879, [all in Group IX], also are referred to.