Patent GB-1243668-A (GB)
Title: An improved process and apparatus for the manufacture of fibrillary products, and products thus obtained
IPC: D01D1/06
Filed: 1968-08-30
Abstract: 1,243,668. Fibrillary products. ALGEMENE KUNSTZIJDE UNIE N.V. 30 Aug., 1968 [2 Sept., 1967], No. 41603/68. Headings B5A and B5B. [Also in Division D1] Filament yarn, thread, film or sheet products consisting of a basic mass with embedded therein a large number of endless threads are produced by a process in which at least two substantially synthetic liquid polymer components such as nylon 6 polyamide and polyethylene terephthalate are placed side by-side to form a single main stream which is repeatedly divided and multiplied to form a multi-layer structure and is then extruded through a die, e.g. a spinneret plate or a casting slit, in which process prior to the main stream being extruded at least a second multi-layer structure is superposed on the first, the layers of the second structure being at an angle of at least 10 degrees to the first multi-layer structure. Preferably, the second multi-layer structure is formed by passing the multi-layer stream through a second mixer in which it is again repeatedly divided and multiplied. The number of layers in the two structures may be different. The film thickness may be from 10 to 100Á but sheets having a thickness of from 0À75 mm. to a few millimetres, in which there extend endless threads having a thickness of from 0À200 to 0À500 mm. can also be made. Yarns may be made from the film by dividing into a large number of ribbons which extend in the longitudinal direction of the film, or by removing the basic mass either entirely or partially from the film, sheet or ribbons, e.g. with a solvent or by a heat treatment. The cross-sectional shape of each of the threads or filaments may be different from that of the extrusion orifice(s), and is uniform along the length. The yarn or thread extruded through a die or a spinneret plate in which there are one or more circular spinning orifices may have a non-circular cross-sectional shape which may be triangular, polygonal, bean-shaped, ribbonshaped, or tri- or multilobal shape. In a particular embodiment the apparatus for spinning monofilaments is at least provided with a feed system for the side-by-side supply of two or more polymer liquids, and a main channel 7 in which the liquids join, and located in the main channel 7, a mixer 8 with stationary guiding members in which the liquids may be repeatedly divided to form a multi-layer structure and a spinneret plate 23 with a single circular orifice 24, in which contiguous to the initial mixer 8 there is at least a second mixer 9 of the same type, which is turned on its longitudinal axis through an angle of at least 10 degrees to the first mixer. The apparatus for casting a film is similar to the above except that the spinneret plate 23 is replaced by a casting slit. For spinning a yarn, a spinneret plate containing a large number of circular orifices is used. Filaments or yarns with a non-circular cross-section are produced when the distance between the second mixer 9 and the spinneret plate with the circular orifice(s) is relatively small. When the distance is relatively large, circular cross-sections result.