Patent GB-1150948-A (GB)
Title: Spinneret for Producing Bi-Component Filaments by Wet-Spinning
IPC: D01D5/32
Filed: 1966-09-19
Abstract: 1,150,948. Spinneret assembly for wet spinning conjugate filaments. AMERICAN CYANAMID CO. 19 Sept., 1966 [24 Sept., 1965], No. 41746/66. Heading B5B. As shown in " exploded " form in Fig. 1, a spinneret assembly or spinning head for wet spinning conjugate filaments comprises a primary distribution plate 1 for distributing two spinning solutions A and B, provided with external threads 18, and internal threads 11, an intermediate plate 2 with two rows of staggered holes 22 and 23, a final distribution element in two pieces 3, shown partly broken away in Fig. 1 and in more detail in Fig. 3, which is a section along 3-3 of Fig. 5, a spinneret plate 4 with orifices 20, an outer clamp ring 5 having internal threads 19 and an internal clamping element 6 with a clamp flange 8, body 10 and external threads 9. As all the elements shown in Fig. 1 are annular, when the stack of plates is clamped together, as shown in Fig. 2, the spinning head thereby formed has a central passageway through which the coagulating liquid of the bath can flow. The two solutions A and B enter through pairs of pipes 13A and 15B respectively in plate 1 which is provided with two concentric grooves 14 and 16. Plate 2 mounts on the front face of plate 1 with the outer row of holes 22 registering with the groove 14 and the inner row of holes 23 with the groove 16. Plate 2 transforms the grooves 14 and 16 into conduits. Fig. 5 is a plan view (partly broken away to illustrate its three levels) of two plates forming the final distribution member 3 for the two different solutions A and B. Openings 24 in the rearmost level of the member 3 communicate with the holes 22 of plate 2 and with elements in the middle level of the member 3. Openings 25 in the rearmost level of the member 3 communicate with holes 23 of plate 2. The front level of member 3 is shown at 29 in Fig. 3. The concentric interrupted openings 27 and 28 (Figs. 3 and 5) are opposite the corresponding solid portions 30 and 31. In the front plate 29 are also machined septa 32 which are in the form of short concentric cylinders. Each septum is opposite the centre of an annular row of spinneret holes 20. Laminar streams of spinning solutions flow on the opposite sides of each septum. With the spinneret plate 4, the septa define annular channels through which the two solutions flow. A very fine mesh (e.g. 200 mesh) screen 21 is located between the edges of the septa and the back of the plate 4 (Fig. 2). This screen produces slight local turbulence at the interface of the streams of spinning solutions A and B so that a slight local mixing of the solutions occurs at the interface and separation of the components of the bicomponent filament formed when the filaments are coagulated is thereby prevented. In a second embodiment of the invention the final distribution plate-shaped element 3 is of such a design that it can be produced as a single unitary structure. The spinning head may be used for producing acrylonitrile polymer bicomponent filaments by wet spinning simultaneously two dissimilar solutions of the polymer dissolved in hot concentrated solutions of sodium thiocyanate into a coagulating bath of cold dilute aqueous sodium thiocyanate.