GB1093170A - Crimped voluminous yarns containing composite polyester filaments and a process for the production thereof - Google Patents

Abstract

1,093,170. Voluminous composite polyester yarns. SOCIETE DE LA VISCOSE SUISSE. Dec. 17, 1965 [Dec. 18, 1964], No. 53701/65. Heading B5B. [Also in Division D1] Yarns consisting wholly of side - by - side composite polyester filaments having a capacity for crimping or becoming voluminous spontaneously, or partly of such composite filaments and partly of unitary polyester filaments, are produced by melt spinning simultaneously through each of some or each of all of the orifices of a spinneret two polyesters of identical chemical composition and the same or different mean molecular weights to form composite filaments the components of which, before the filaments are stretched, differ in double refraction by at least 0À002, stretching them at a temperature of at least 65‹ C., and subsequently relaxing the tension on the yarns. In the case of yarns consisting of both composite and unitary or homogeneous filaments, some of the polyester melts are separately extruded through different spinneret orifices to form unitary filaments, which are collected in a bundle with the composite filaments to form the yarn. When the yarns consist exclusively of composite filaments they may be heat set while free from tension after having undergone spontaneous crimping. Yarns containing both composite and unitary filaments may be stabilized after relaxation of the stretching tension by twisting and/or heat-setting under tension. The polyesters constituting the composite filaments preferably differ in their reduced viscosity by at least 0À1. Fibre-forming saturated polyesters having a melting point above 100‹ C. may be used for the production of the yarns, including polyethylene terephthalate, poly - (1,4 - dihydroxymethylcyclohexane terephthalate), copolyesters of terephthalic acid, isophthalic acid and ethylene glycol, and also polyester ethers. A melt spinning head 1 for the production of yarns of composite filaments (Figs. 1 and 2) is subdivided internally into two chambers 2 and 3 supplied with molten polyesters P1 and P2, each by means of a titre pump. The two melts flow through the openings 4 and 5 into the chambers 6 and 7. Along the edge 9 of tapering partition 8 the two melts P1 and P2 unite and flow without mixing jointly through the spinneret orifices 10. Figs. 5 and 6 illustrate a melt spinning head 14 for the production of yarns consisting of both composite and unitary filaments. The melts P1 and P2 flow from the two ante-chambers 15 and 16 through a number of openings 17 and 18 into chambers 19 and 20 separated by the partition 21 tapering downwardly to an edge 22 and extending almost as far as the inlets of the spinneret orifices 23. The two melts P1 and P2 flow together from the chamber 19 and 20 through the spinneret orifices 23 and form separate composite filaments. Only the melt P1 flows out of the spinneret orifices 24, and only the melt P2 out of orifices 25, unitary filaments being thereby formed.