| 摘要 |
1,057,579. Polyester and polyolefin filaments. IMPERIAL CHEMICAL INDUSTRIES Ltd. Dec. 13, 1965 [Dec. 24, 1964; May 19, 1965], Nos. 52465/64 and 21219/65. Heading B5B. A process for the production of filamentary materials comprises extruding a linear, fibreforming polyester or a stereo regular poly-α- olefin in the molten state through a spinneret having one orifice or a plurality of orifices, the orifice or each orifice having a cross-sectional area within the range of 0.2-12 sq. mm., and attenuating each resultant stream of polymer by the application of a force or forces acting along the length of the stream of polymer in a direction away from the spinneret face, such forces being operative at least in the region of the stream of polymer situated between the exit of the spinneret orifice and the point in the polymer stream where reduction is cross-sectional area ceases due to solidification of the polymer, the flow rate of polymer through each orifice being between 0-1 g. and 4 g. per minute, the linear speed of the fibre at the point in the polymer stream where reduction in cross-sectional area ceases due to solidification of the polymer being between 610 and 2,740 metres per minute and there being directed across each stream of polymer a stream of quenching fluid of mean velocity at the polymer stream of between 45 and 180 metres per minute. Both circular and non-circular cross-section spinneret orifices may be used and the spinneret holes may be grouped in such a manner that the streams of molten polymer from a group unite immediately after leaving the spinneret orifices to form a single stream of polymer in which case the group is treated as a single orifice of which the effective crosssectional area is the sum of the cross-sectional areas of all the orifices in the spinneret holes in the group. In an example, Y-shaped spinneret orifices are used. The quenching fluid may be air, nitrogen or a vapour, suitably steam, and may have liquid droplets present therein. Heat treatment of the spun filaments may be carried out by contact with hot water, with a hot gas or with a hot surface. The tension in the spun filaments may be relaxed to produce crimped filaments. The spun filaments may be heat treated during or after relaxation. The spun filaments may be drawn at or above room temperature prior to development of the crimp by relaxation of the tension. Alternatively the self-crimping yarn may be held under tension while being cut into staple fibre whereupon on relaxation formation of crimp occurs. The cut fibre may then be heat treated to stabilize the crimp. Alternatively, development of crimp may be deferred until a fabric has been made from the self-crimping yarn by deferring any heat treatment and/or maintaining a tension in the yarn until after the fabric is constructed, the degree of crimping achieved in the fabric being dependent upon fabric construction. Specified polyesters include polyethylene terephthalate and specified poly-α- olefins include isotactic polypropylene. Examples are given, |
