GB1404658A - Core yarns - Google Patents

Abstract

1404658 Yarns IMPERIAL CHEMICAL INDUSTRIES LTD 18 Sept 1972 43075/72 Headings D1F and D1W A continuous filament, textured core yarn comprises a false-twist crimped core and a wrapper portion, constisting of one or more continuous false-twist textured filaments of higher crimp amplitude than the core filaments, intermittently wrapped, singly or collectively in helices (in similar or alternating S- or Z- direction) around the core to form an integrated yarn of variable bulk along its length. The or each wrapper filament form (reversing) helices at intervals along its length and periodically looping into the core filaments. Core and wrapper filaments may be of similar or different material and/or chemical nature such as nylon and polyethylene terephthalate, denier, cross-sectional form e.g. circular or trilobal, colour, construction e.g. conjugate, side-by-side or sheath core filaments, and'or modified (as by heat treatment) to impart different physical properties. The false-twist texture in the core filaments may be at least partly drawn out to reduce its crimp amplitude. Two core yarns of opposite torque may be doubled or a single yarn may be heat treated to reduce the residual torque, in order to provide a "balanced" knitting yarn. In the process shown, undrawn yarns 26, 27, of different birefringence values from packages 28, 29, are withdrawn through a guide 30 by a feed roll assembly 31, pass over a heated plate 37, through friction twist element 39 (or a false-twist spindle) and are overfed by a draw roll assembly 41, over another heater plate 47, thence to a relax roll 51.