US 3817680 A
To provide for smooth flow of synthetic spinning liquid from a spinning plate, formed with spinning ducts extending through the thickness of the plate, the exit surface of the plate has a coating of adjacently located crystalline columns, of a thickness in the order of between 2-20 mu m, the layer having a fine crystalline structure, in a plane parallel to the coated surface of the plate and the layer being made of at least one metal of titanium, vanadium, niobium, chromium, molybdenum, tungsten, iron, cobalt, nickel, gold, silver, tantalum, copper, aluminium, or platinum-type metals; these materials are preferably applied by vacuum condensation from a gaseous phase at a pressure of less than about 10<->1 mm Hg.
Claims available in
Description (OCR text may contain errors)
El States Patent 1 1 1111 3,817,680
Gultner et al. June 18, 1974 SYNTHETIC FIBER SPINNING PLATE 3,573,092 3/1971 11011181211. 117/107 x WITH COLUMMAR COATING LAYER  Inventors: Wolfgang Giiltner, Bad Hersfeld; Primary a inerR0b8rt D. Baldwin Wolfgang Hohmann, Neuberg; Rolf Attorney, Agent, or Firm-Flynn & Frishauf Ruthardt, Hanau, all of Germany  Assignee: W. C. l-leraeus Gmbl-l, Hanau,
Germany  ABSTRACT  Filed: (Rt 2 1972 To provide for smooth flow of synthetic spinning liqu1d from a spinning plate, formed with spinning ducts PP N04 293,994 extending through the thickness of the plate, the exit surface of the plate has a coating of adjacently located  Foreign Application Priority Data crystalline columns, of a thickness in the order of be- S t 30 1971 G 2148773 tween 2-20 pm, the layer having a fine crystalline ep emany structure, in a plane parallel to the coated surface of the plate and the layer being made of at least one g 425/461 117/ metal of titanium, vanadium, niobium, chromium, mo-  Fie'ld 463 461. lybdenum, tungsten, iron, cobalt, nickel, gold, silver, 1 17/167 6 2 tantalum, copper, aluminium, or platinum-type metals;
these materials are preferably applied by vacuum condensation from a gaseous phase at a pressure of less  References Cited than about 10 1 mm H UNITED STATES PATENTS g 2,848,737 8/1958 Poetter et al. 425/464 5 Claims, 1 Drawing Figure T'IIIIII'" SYNTHETIC FIBER SPINNING PLATE WITH COLUMMAR COATING LAYER The present invention relates to a spinning plate, formed with a plurality of ducts, particularly to make synthetic fibers from organic polymers, according to the liquid spinning process, and more particularly to such spinning plates made of steel.
In the manufacture of synthetic fibers from organic polymers in accordance with the melt spinning process, liquid polymers are extruded in normal spinning direction from the spinning ducts of the spinning plate. As a result, the nozzle end of the spinning ducts is subject to disturbances, and the spinning process is subject to disturbances. If the melted polymersdeviate substantially from the directed flow, drips of liquid, melted polymers may form, resulting in an interruption of the spinning process. Deviation from the spinning path, and migration of the melted polymers can be observed particularly when the laminar flow at the terminal edge of a spinning duct is disturbed by irregularities in the geometry at the exit edges, or by wetting of the limit or terminal zone of the exit end of a spinning duct.
It has previously been proposed to spray the exit surface of the spinning plate with silicone spray, or from time to time to apply a silicone compound by means of a brass spreader. These methods interfere with continuous production and are undesirable when actually carrying out spinning from a melt of organic polymers.
It has also been proposed to coat the surfaces of spinning plates with a layer of polytetrafluorethylene in order to prevent migration or deviation of the melted polymers from a spinning duct (see German Pat. Publication l,660,557), in order to inhibit wetting of the spinning plate with liquid polymers in the region of the edge zone of a spinning duct. The polytetrafluorethylene layer, however, is insufficiently tough and sturdy and therefore it is not possible to avoid irregularities in shape or geometry of the exit edges of the spinning ducts, or the spinnerets, so that migration of liquid polymer, caused by irregularities in geometry, is not prevented.
U.S. Pat. No. 2,848,737, describes a spinneret made of hard metal which, in order to protect the surface adjacent the nozzle, is plated with a'chromium layer. Such plated nozzles do not insure elimination of the difficulties which arise in spinning organic polymers from a melt, caused by migration of material used for spinning.
It is an object of the present invention to provide a spinning plate in which the stability of shape, that is, the geometry of the exit edges of the spinning ducts is reliably insured and which further inhibits wetting of the edge zones of the exit edges by the melted liquid polymers which exit from the spinning ducts during the spinning process.
SUBJECT MATTER OF THE PRESENT INVENTION It has been found, surprisingly, that surfaces on the spinning plate which are formed with a very thin layer, of about 2-20 um of crystal columns, oriented perpendicularly to the direction of the spinning plate surface (that is, parallel to flow direction) to solve the difficulties arising when spinning a melt of polymers, the crystalline layer being made of at least one of the metals of titanium, vanadium, niobium, tantalum, chromium,
molybdenum, tungsten, iron, cobalt, nickel, gold, silver, copper, aluminum and platinum metals, the crystalline layer having a fine crystalline structure in a plane parallel to the surface of the spinning plate. Platinum-type metals, as used in the present specification, are the metals platinum, palladium, rhodium, iridium, ruthenium and osmium.
In accordance with a preferred feature of the invention, the thickness of the layer of crystal columns is about between 6 to 12 pm. The crystals of this layer have a preferred orientation perpendicular to the surface of the spinning plate. Thus, the end terminal of the spinning duct has a crystalline metallic structure which is columnar and oriented in the direction of flow of the organic polymers, which thus do not interfere with laminar flow of the liquid polymers eminating from the duct in the spinning plate. In a plane parallel to the spinning plate, the crystalline layer has a fine crystalline surface structure, which, based on its fine crystalline structure effectively prevents wetting of the surface with the melted liquid polymers at the surface. The columnar crystalline structure, parallel to flow direction and at the exit ends of the ducts is coarsely crystalline, however.
It has been found that no migration of melted liquid organic polymers will occur at the terminal ends of the ducts in the spinning plates, even over long periods of time. Layers in which the crystalline columns are of titanium, vanadium, niobium, or chromium are particularly suitable.
In accordance with the feature of the invention, the crystalline layer can be so made that at least one metal of the group aforesaid is precipitated in a vacuum of less than 10 mm Hg, by condensation from the gaseous phase, on the surface of the spinning plate. In a preferred form, the metal is vaporized on the spinning plate at the pressure of less than 10 mm Hg. In accordance with a particularly suitable embodiment, the spinning plate is maintained at a temperature of at least C during the coating process.
The invention will be described by way of example with reference to the accompanying drawings, wherein the single FIGURE is a schematic transverse sectional view through a spinning plate.
The spinning plate 1 is made of steel and is formed with a plurality of spinning ducts 2, adapted to be connected to a source of melted polymer, not shown. The liquid melted organic polymer passes through the spinning duct in the direction of the arrows 3.
In accordance with the invention, the surface of the spinning plate from which the melted organic polymers exit, or emanate, is coated with a crystalline layer 4 which consist essentially of adjacent crystal columns extending at right angles to the surface of the spinning plate 1. The crystal columns are so arranged that the crystalline layer 4, in a plane parallel to the surface of the spinning plate, exhibits a fine crystalline crystal structure.
1. Synthetic fiber spinning plate comprising a structural plate formed with spinning ducts extending through the plate in a direction transverse to the plate surface, and a non isotropic coating layer of adjacent crystalline columns, of a thickness in the order of between 220 mm, said layer having a coarse columnar crystalline structure parallel to the direction of the spinning ducts at the exit ends columns are made of a material comprising at least one of the metals of the group of titanium, niobium, vanadium or chromium.
4. Plate according to claim 1 wherein the platinum metals comprise at least one of the metals of the group of platinum, palladium, rhodium, iridium, ruthenium and osmium.
5. Plate according to claim I wherein the structural plate is formed of steel.
7 UNITED STATES PATENT, OFFICE CERTIFICATE OF CORRECTION Patent No. 3 81 7 68() Dated I June 1 8 1 97 lnventofls) Wolfgang GOLTNER et a].
It is certified that error appearsvin the above-identified patent and that said Letters Patent are hereby corrected as shown below:
The name of the first inventor should read as follows 2 Wolfgang GOLTNER and the title should read as follows "SYNTHETIC FIBER SPINNING PLATE WITH COLUMNAR COATING LAYER" Signed and sealed this 10th day of December 1974.
(SEAL) Attest: I
I'IcCOY w. GIBSON JR. 0. MARSHALL DANN Attesting Officer Commissioner of Patents FORM uscoMM-Dc aoa1eq= e9 US. GOVERNMENT PRINTING OFFICE: Q59 6-366'33,