Patent GB-1273111-A (GB)
Title: Apparatus for producing composite fibres
IPC: B29C48/05
Filed: 1970-03-06
Abstract: 1,273,111. Spinning conjugate filaments. SNAM PROGETTI S.p.A. 6 March, 1970 [11 March, 1969], No. 10985/70. Heading B5B. A spinneret suitable for melt-spinning conjugate filaments from two ploymer components in side-by-side relationship is constructed from a spinneret plate, having a plurality of extrusion orifices and a distribution plate adjacent to and upstream of the spinneret plate. Each extrusion orifice is in communication with two feed-ducts, which project over different cross-sectional portions of the extrusion orifice, or an inward extension thereof, in such a fashion that no two portions, as viewed along the axis of the extrusion orifice, overlap. These portions correspond in shape to the cross-sections of the respective polymeric components in the spun filament. The feed-ducts are disposed at different points along the length of the extrusion orifice or the inward extension thereof, and there is no inward extention of that portion or the extrusion orifice over which a feed-duct projects beyond the point at which the relevant feed-duct meets the extrusion orifice. The arrangement is such that a flowing stream of the melt of one polymeric component is poured through one feed duct (where it obtains the desired cross-section), and the other flowing stream of the melt of the other polymeric material is poured through other feed-duct disposed downstream of the first feed-duct and is brought together with the flowing stream of the melt of the first polymeric component, but mixing between the polymeric components is substantially prevented except at the interfaces of the streams. The feed-ducts are generally defined by the spinneret plate and the distribution plate, but in some cases, the feed-ducts may be provided solely in either plate. Preferably a distance of at least 2 mm., as measured along the line of extrusion should separate the points at which adjacent feed-ducts project over the extrusion orifice. The feed-duets are generally in communication with collection chambers in the spinneret. The distribution plate and the spinneret plate can be so designed that they form seals between them. The extrusion orifices may be arranged on the circumference of a circle, this is particularly advantageous when two polymeric components only are used. In the embodiment shown in Fig. 1, two polymeric components are melted and introduced separately into the supply chambers 1 and 2 formed in the distribution plate A. One component passes from 1, via the supply channel 3 to the collection chamber 5, 6 and then into inward extension 10 of the extrusion orifice 9, formed in the spinneret plate B. The other component reaches the orifice via distribution channel 4, collection chamber 5, 7, 8 and feedduct 11. The extrusion-orifice 9 is circular and feed-duct 11 extends to the diameter of the circle. The channel 10 above 11 is thus semi-circular and so both components occupy a semi-circular cross-section of the extrusion orifice 9 and thus of the extruded filament also. In this embodiment the orifices are arranged around the circumference of a circle and the collection chambers 5, 6, 7 and 8 and the feed-duct 11 and the inward extension 10 are formed by circular channels cut into A and B such that the orifices 9 are equidistant between collection chambers 5, 6 and 7, 8.