GB1028464A - Artificial filaments of lobed cross-section and spinnerets therefor - Google Patents

Abstract

1,028,464. Artificial filaments of lobed crosssection. CELANESE CORPORATION OF AMERICA. Jan. 16, 1963 [Jan. 30, 1962], No. 1920/63. Heading B5B. [Also in Division A2] Artificial filaments have a cross-section consisting of a pair of legs connected at approximately their mid-points by a bar, one leg being straight and the other curved or bent so that its mid-point is nearer to the straight leg than are its ends, as illustrated, for example, in Figs. 4, 6, 8, 10 and 12 (not shown). They may be produced by dry-spinning a solution of a filmforming substance such as cellulose acetate through a spinneret having one or more orifices defined by a compact geometric figure into each of two opposite quarters of which a protuberance projects so deeply as to occupy most of said quarter and into another quarter of which a third protuberance projects less deeply, as illustrated, for example, in Figs. 5, 7, 9 and 11 (not shown). The geometric figure may be a full circle and the protuberances may be arcuate, the opposed protuberance being of equal radius and projecting to equal depths into the circle. As illustrated in Fig. 3 (not shown), all the protuberances may be arcs of identical circles the radii whereof are 40 to 80% of that of the full circle and the opposed protuberances extend into the full circle to within a distance from the centre of the full circle which is 8 to 30% of the diameter thereof of circle while the remaining protuberance extends to within a distance from the centre of the full circle which is 20 to 45% of said diameter. The opposed protuberances may have straight sides which are uniform and equal and the opposing sides of each of the two protuberances may be at angles of 55 degrees to 125 degrees of each other. In an example, a 25% solution of secondary cellulose-acetate in acetone is dry spun through a spinneret provided with holes shaped as illustrated in Fig. 3 (not shown) to form 8 denier filaments having a cross-section shaped as illustrated in Fig. 2 (not shown), 50 yarns of 140 filaments each are bundled together and stuffing box crimped to the extent of 8 crimps per inch to yield a tow which is opened in a conventional manner, sprayed with 6% of dimethoxyethyl phthalate as a plasticizer, condensed in shape, wrapped with paper, cut into cigarette filter plugs and cured at room temperature.