GB1012526A - Spinnerets and methods of making them - Google Patents

Abstract

1,012,526. Spinnerets. ROHM & HAAS CO. May 7, 1963 [May 9, 1962], No. 18007/63. Heading B5B. A spinneret comprises a plurality of openended capillary tubes 2 having capillary passages 3 with their axes disposed parallel to one another, the tubes being united into an integral unit by means of a cement 4 disposed between the outer walls of the tubes (Figs. 1 and 2). The tubes may be of glass, silica or metal, e.g. platinum, palladium, rhodium and their alloys, or nickel, monel metal or stainless steel. In Fig. 3, the tubes 2 are separated by rods 4. The tubes may be cemented within an outer sheath, preferably provided with a radially projecting rib. The sheath may be made of metal, glass or plastic or resinous material, e.g. polyvinyl chloride, polyethylene, nylon, and polyethylene glycol terephthalate. Metal sheaths may be 0À25-3À5 mm. thick, and plastic, glass or ceramic sheaths may be 1À25-6 mm. thick. Specified cements include phenoplasts, aminoplasts, polyepoxides, and vinyl resins, e.g. polyvinyl chloride, or plastisols containing polyvinyl chloride, with or without crosslinkers. Thermosetting materials, if used, may include curing catalysts. Cold-setting adhesives and molten salts, e.g. silver chloride, and oxides, e.g. magnesium oxide, may be used, or a fusible powdered glass frit. Spacing between adjacent passages in the spinneret may be varied by using capillary tubes having greater or less wall thickness, or by the use of rods of any suitable cross-sectional shape, e.g. square, hexagonal or circular. Such rods may be of 0À12 to 0À8 mm. thickness. Instead of rods, extra cement may be used, or the tube spacing may be controlled by the use of bored, etched or woven templates. The number of tubes may vary widely, from 6-12 on the one hand to 30,000-50,000 on the other, the overall width or diameter of the spinneret face being from # inch to 3 inches or more. The capillary passage length may vary from 0À75-75 mm. or more, preferred spinnerets having passages of 5-15 mm. in length, and the capillary passage diameter maybe 0À05-0À3 mm. Adjacent capillary passages may be spaced apart by a distance of from about 0À038-0À8 mm. Spinnerets may be made by forming an assembly of capillary tubes with their axes in parallel relationship, uniting the tube assembly into a unitary member by disposing and then setting a cement between the outer walls of the tubes, and then cutting the unitary member in a transverse direction to form at least one spinneret. In Fig. 4 a bundle of tubes 2 having closed ends 6 are inserted in a sheath 5 fitted with a plug 7 and filled with cement. After setting, the assembly is cut transversely to form spinnerets, the sheath being retainedif desired. In Fig. 5, a similar method is used, but a sheath having ribs 8 is used and the tubes, which are closed at both ends, are spaced by the use of foraminous templates 36. After the cement has set the assembly is cut to provide spinnerets having at least one rib. In a modification of this method, a bundle of glass tubes is drawn while softened by heat until the inside diameter of each tube is about 0À05-0À3 mm., the drawing causing the tubes partially to fuse together, and the drawn assembly annealed and cemented, and cut transversely after the cement has set. A bundle of glass tubes may be inserted in a closefitting glass sheath, and the entire assembly of sheath and tubes is then drawn. A metal wire resistant to oxidation may be inserted in the bore of a capillary tube of glass having a lower coefficient of expansion than the metal wire, a plurality of such glass tubes having such wire cores assembled in to a bundle, the wires clamped at their ends and placed under tension, the assembly heated while so clamped to cause the tubes to partially fuse together and the wires to fit tightly in each glass tube, cooled, annealed, the wires removed, and the tube assembly cemented. After setting of the cement the assembly is then cut to form spinnerets. In Fig. 9, a simple multi-hole spinneret is formed by cementing a single row of parallel capillary tubes 2 together to form a thin wafer which is then cut transversely to provide spinnerets of any desired length. In Fig. 10, a plurality of wafers, in each of which tubes 2 are separated by rods 2a, are assembled to form a pack. Spinneret mountings are shown in Figs. 11, 12 and 13. In Fig. 11, the cylindrical spinneret 9 is held by the rubber ring 10 and sealing gasket 15 between the coupling unit 16 and fitting 11. In Fig. 12, a spinneret 9a with a flange 8 is held against the sealing gasket 20 and fitting 23 by the coupling unit 21. In Fig. 13, a plate-type spinneret 9b is held against the sealing gasket 26 and mounting unit 27 by the coupling unit 25. U.S.A. Specification 2,914,376 is referred to.