GB1292388A - Hollow filaments - Google Patents

Abstract

1292388 Hollow filaments E I DU PONT DE NEMOURS & CO 25 Feb 1970 [26 Feb 1969] 9023/70 Heading B5B A melt-spun textile filament is composed of a thermoplastic synthetic polymer and has at least three voids extending substantially continuously throughout its length; these voids account for a total of between 10 and 35%, preferably between 10 and 25%, of the filament volume, and the filament has an outer surface substantially free from re-entrant curves. Fig. 1 shows a spinneret orifice suitable for use in melt-spinning these filaments. Figs. 1a, 1b and 1c show cross-sections of filaments produced by orifices of this type. The orifice may be designed so that it has 4 T-shaped components, in which case a fibre such as that illus- trated in Fig. 3 is produced, that is one with substantially quadrilateral voids. As illustrated in Figs. 1a, 1b and lc and in Fig. 3, the fibres may have a quadrilateral cross-section. Other shapes mentioned are triangular and pentagonal. Conventional polymer additives such as dyes, antistatic agents &c. may be added before, during, or after polymerization and spinning, and the filaments may be crimped and textured conventionally, usually without detriment. Both pre-ooalescent and post-coalescent spinning techniques may be used, but the latter is preferred since the former requires the injection of an inflating agent into the polymer to maintain the void structure. The examples illustrate the preparation of fibres of poly-(hexamethylene adipamide) by the process of the invention, the fibres being spun, hot-drawn and textured in a continuous operation. Polyethylene terephthalate fibres are also disclosed.