GB822813A - Improvements relating to yarns and their manufacture - Google Patents

Abstract

822,813. Crimping yarn; composite yarns; heating arrangements in textile spinning &c. machines. DEERING MILLIKEN RESEARCH CORPORATION. Feb. 24, 1956 [Feb. 24, 1955], No. 5851/56. Classes 120(2) and 120(3) Monofilament or multifilament yarn of thermoplastic, hydrophobic material e.g. nylon or ethylene - glycol - terephthalic acid polyesters, is heated and continuously passed over a sharp edge so that the yarn follows an angular path with the edge at the apex thereof, contacting the edge at an elevated temperature (180‹-450‹F.) to impart to the yarn latent non-torsional internal stresses which subsequently may be relaxed to develop crimp and stretch properties: the yarn, in passing along the angular path and after leaving the edge, is combined and intertwisted with a second yarn which may be of the same material as the first yarn and/or of continuous filaments or spun yarn e.g. of wool, cotton, nylon, cellulose acetate or viscose rayon. In the processes exemplified, the linear speed and tension of the yarn are 1-450 feet per minute and 0.15-0.28 grms. per denier, the angle of the yarn path at the apex is less than 120 degrees, the radius of curvature of the edge is 2-15 microns, the angle of approach of the yarn to the edge is less than 100 degrees and the angle of departure therefrom is less than 50 degrees, the yarn may be positively cooled on leaving the edge and the doubling twist is 3-5 turns per inch. Relaxation of the yarn to develop crimp in the first yarn component may be accompanied by heating (of plied yarn or fabric woven or knitted therefrom) to 120‹-145‹F. e.g. fabric is immersed in a bath of cold water which is agitated and its temperature raised to 140‹F. In the apparatus shown, a yarn end 16 is led from a package 14, through guide 18, about a tension regulator 20, around a blade assembly 22, through a guide 24 to driven rolls 26 where it is joined by a yarn 34 led from a package 32, through a guide 36 and tension regulator 38 and the two yarns are led through a guide 39 and intertwisted by means comprising a spindle 42, ring 44 and traveller 46. The assembly 22 comprises an arcuate metal strip 48 heated directly, by its own electrical resistance, from a variable transformer 54 and carrying (in a holder 60) a blade 62 having a sharp edge 64. A single 1-5 inches wide strip, as at 48, may heat several blades having heat insulation e.g. foam glass, therebetween.