GB1357139A - Torque controlled voluminous set yarns - Google Patents

Abstract

1357139 Modified torque yarns W A SEEM N J STODDARD and R W STODDARD 1 June 1971 [5 April 1971] 18255/71 Heading D1F A method of making set yarn by modifying the torque of an advancing multifilament falsetwist textured yarn comprises overfeeding the false-twist textured yarn through heating and cooling zones in a substantially tensionless condition, and then passing the tensionless yarn through a fluid-whirling chamber in which the yarn is subjected to low pressure fluid to false twist it in a direction opposite to that received in the initial false-twist texturing process, the pressure being controlled to produce a lesser degree of twist than in said first process and collecting the yarn. By 'substantially tensionless' is meant tension sufficient to prevent pigtailing but not sufficient to straighten the crimps in the yarn. The false-twist textured yarn is preferably formed in a continuous process with the set yarn. In a preferred embodiment, an unprocessed yarn Y is led from a supply bobbin 10 via feed rolls 20 and heater 30 to a false twist spindle 40. The false twist textured yarn thus produced is then led directly to feed rolls 50 and heater 60. The heated yarn is led directly to a fluid false twister 80 which imparts a false twist to the yarn in the opposite direction to the twist in the false-twist textured yarn. The modified torque yarn is then takenup on roll 100. The fluid false twister 80 comprises a fluid-whirling chamber 154 having a cylindrical side wall 142 and a fluid inlet passage 152 connected thereto. The inlet passage 152 is disposed tangentially to the side wall and has an axis disposed in a plane perpendicular to the axis of the side wall. The chamber 154 also has end plates 144 perpendicular to the wall axis, the plates 144 having axial bores 148 for the passage of the yarn through the chamber. The fluid stream introduced into the chamber causes the yarn to balloon and also causes the filaments of the yarn to separate. The contact surface of the heater 60 is preferably arcuate to improve yarn/heater contact. The filaments of the yarn may be made of polyester or polyamide. In a preferred embodiment, the false twist imparted to 'the yarn is less than 25% of the twist heat-set in the yarn during the production of the false-twist textured yarn. The modified torque remaining in the set yarn is preferably substantially zero but may be opposite to the normal residual torque of the falsetwist textured yarn. The yarn is preferably used to make knit tricot or knit jersey products.