Plastic and nonmetallic article shaping or treating: processes – Forming continuous or indefinite length work – Shaping by extrusion
Patent
1996-07-30
1998-03-31
Tentoni, Leo B.
Plastic and nonmetallic article shaping or treating: processes
Forming continuous or indefinite length work
Shaping by extrusion
425463, 425464, D01D 400, D01D 508
Patent
active
057334927
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a spinneret of a gold and platinum-containing metal alloy with spinning orifices, the face provided with the spinning orifices being convex, and the spinneret being provided with a raised edge.
Such a spinneret is known. In W. Funk and R. Schumm, "Spinndusen-Bauteile fur die Chemiefaserindustrie," Chemiefasern/Textilindustrie, June 1972, 518-522, spinnerets to be used in wet spinning processes are disclosed. These spinnerets are made of metal alloys of gold, platinum, and rhodium. An alloy comprising 49 wt. % of Pt may be heat treated to a hardness of 330 Vickers, an alloy comprising up to 30 wt. % Pt to a hardness of 230 Vickers.
The thickness of the sheet material used fort the spinneret is in the range of 0.2 to 0.8 .mu.m. In order to be able to withstand deformation at higher spinning pressure, the spinning face was made convex and a reinforcing ring was employed to give still greater strength. Yet in spite of these measures the spinneret will undergo permanent deformation at pressures in excess of about 600 kPa. Deformation of the spinning surface in turn results in a severe reduction of the quality of the fibres produced due to lack of uniformity in fineness, irregular shape, etc.
A spinneret has now been found which does not have the drawbacks indicated in the description of this article.
SUMMARY OF THE INVENTION
The invention relates to a spinneret of a gold and platinum-containing metal alloy, in which the face provided with spinning orifices is convex and the spinneret is provided with a raised edge and a gripping edge at which the spinneret can be gripped in a spinning assembly, the gripping edge being immediately adjacent to the face provided with spinning orifices.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic of a spinneret wherein the gripping edge is flat and at right angles to the direction of the polymer stream entering the spinneret.
FIG. 2 is a schematic of a spinneret wherein the gripping edge is directly in line with the spinning surface.
FIG. 3 is a schematic of a test strip used to measure the tensile strength of the spinneret material.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The face provided with spinning orifices is convex, due to which the forces on the spinneret are distributed over the surface. A spinneret with such a spinning surface is described in JP-04-136207-A, this spinneret having a spherically protruding spinning surface.
It has been found that if the gripping surface of the spinneret is immediately adjacent to the spinning surface, the resistance of the spinneret to high forces is significantly higher than that of spinnerets of a geometry known from, inter alia, the above-cited article. Thus, the particular construction according to the present invention provides a spinneret having substantially greater strength than the known spinnerets, even though it has a very small thickness. Moreover, the strength of a spinneret having a raised edge on its outer side is higher than that of a spinneret without such a raised edge.
An additional advantage of the now found spinneret consists in that it allows the use of highly viscous solutions at high speeds, so that a major economic advantage is obtained.
In the case of the spinneret according to the present invention, the spinning surface can make one angle with the gripping edge or not. The gripping edge is usually a flat surface in which the spinneret is held fast. In that case, the bulged spinning surface will make an angle with the gripping edge. Alternatively, the outer part of the spinning surface by which the spinneret is held fast can be used as the gripping edge, the gripping edge thus being an extension of the spinning surface but not actually part of the spinning surface. In that case, the spinning surface does not make an angle with the gripping edge.
The spinning surface has a completely fluent shape, without any angles. Of course, if a flat gripping edge protrudes somewhat because the spinneret is gripped at a short distance from the angle bet
REFERENCES:
patent: 1980234 (1934-11-01), Taylor
patent: 4155730 (1979-05-01), Biberbach et al.
patent: 4839113 (1989-06-01), Villaine et al.
patent: 5472333 (1995-12-01), van der Zel
Derwent Patent Abstract 92-205396/25 (1992).
Patent Abstracts of Japan, vol. 17, No. 79 (C-1027), 1993.
Derwent Patent Abstract 35541S-AF (1971).
W. Funk et al., "Spinndusen-Bauteile fur die Chemiefaserindustrie", Chemiefasern/Textilindustrie, Jun. 1972, pp. 518-522.
H. Schmid et al., "Zur Frage der Korngrosse und Aushartung von Gold-Platin-Legierugen", Metallwissenschaft und Technik, 12, Jg, Jul. 1958, Heft 7, 612-619.
Appeldoorn Jacques Wilhelmus Jozef
Gortemaker Paulus Christiaan Maria
Akzo Nobel N.V.
Fennelly Richard P.
Morris Louis A.
Tentoni Leo B.
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