GB1112168A - Bulking yarns,strands and like filamentary material - Google Patents

Abstract

A multifilament or monofilament yarn (or two or more such yarns assembled into a strand which is permanently retained or separated into individual yarns after processing) of regenerated cellulose or cellulose esters or ethers or fibre blends thereof, or polyamides, polyesters, polyolefins, polyurethanes, or vinyl polymers or copolymers, is bulked by false-twisting and heat-setting. From a package (10) yarn (11) passes through eyelets (12 and 13) over a twist-stopping guide (14) and immediately in contact with the curved surface of an internally heated roll (15) which rotates at a peripheral speed equal to or higher than the linear speed of the travelling yarn. The yarn passes around 240-270 DEG of the circumference of the roll in a helical path, on to and through a false-twist spindle or tube (16), thence around and through the nip of take-up rolls (18, 19) the speed at which one thereof is driven determining the rate at which the yarn is processed. The bulked yarn then proceeds with "overfeed" or "underfeed" to mechanism whereby it is wound into a "soft" or "hard" package. In its passage around the roll, the yarn under tension is rolled from side to side by the effect of friction forces between itself and the roll surface, thus ensuring efficient heat transfer thereto; the false-twist in the yarn varies along with the helical path and the effect of heat-setting such twist causes random distribution of coils, curls or crimps in the individual filaments of the bulked yarn.