GB1180329A - Spin-Drawing Process for Polyester Filaments - Google Patents

Abstract

1,180,329. Spin-drawing polyester filaments. FARBWERKE HOECHST A.G. 3 Sept., 1968 [31 Aug., 1967], No. 41851/68. Heading B5B. Filaments of a linear polyester are produced by a spin-drawing process which comprises spinning filaments of the linear polyester, preferably polyethylene terephthalate, subjecting them at a temperature within the range of from 10‹ to 120‹ C. to a permanent elongation corresponding to a value on that section of the stress-strain curve of the filaments in which the curve passes from a linear gradient to a section in which drawing takes place without a corresponding increase in the stress, and subsequently drawing the filaments. In a preferred embodiment, Fig. 2b, the apparatus comprises a spinning device, a delivery roller 2 which rotates at a rate which corresponds to the rate of spinning, and elongation- and draw-rollers, 9 and 7, in which the elongation roller 9 is a coaxial two-step roller whose diameter ratio corresponds to the ratio of elongation of the desired permanent elongation. The step roller is preferably heated to the drawing temperature, so that the elongation takes place at above the second order transition temperature of the filamentary material. If the step roller is not heated then the drawing is carried out between heated roller 7 and a following draw-off roller which draws the filament at a higher speed. In another embodiment the step roller is replaced by two rollers and the filament is preferably elongated between these two rollers when heated and is subsequently drawn over unheated roller 7. If one heated roller is omitted then the elongation takes place between unheated delivery roller 2 and the heated roller. In this case, the filament is elongated below the second order transition temperature.