FI92845C - The spinning nozzle - Google Patents

Abstract

In a spinneret, the spinning plate having the spinning capillaries (9) consists, according to the invention, of a carrier plate (2) having holes (7), especially stepped bores, into which are inserted or pressed small plates (8) containing the capillaries (9). The carrier plate (2) can therefore be of any thickness and consist of material of any strength, in order to achieve a high pressure resistance, without making it difficult to produce closely arranged capillaries (9), since the capillaries can be made in the softer small plates (8). <IMAGE>

Description

92845

The present invention relates to a spinning nozzle comprising a nozzle head and a spinning plate comprising a highly sta-5 carbon support plate, preferably made of precious metal, having holes and small plates fitted or pressed into the holes, the small plates comprising a plurality of capillaries, the plates being of a material having a hardness lower than that of the base-10 tin plate, preferably gold, silver or tantalum.

Spinning nozzles are needed to make fibers with a spinning mass of organic or inorganic material as the raw material. The flowing or pumpable material, which in most cases has a rather high viscosity, is pressed through differently shaped nozzle capillaries, after which, depending on the methods, it is formed into fibers after different treatment cycles.

A good spinning nozzle is expected to have quality characteristics such as hole quality (dimensional accuracy), smoothness of bore-20 hole walls, sharpness of borehole outlet edges, smoothness of nozzle bottom, corrosion resistance, and specially designed spinning channels. Particular emphasis must be placed on the importance of the strength of the spinning nozzles, since the spinning nozzles are subjected to enormous pressures when the pulp is being spun. Especially when spinning high viscosity cellulose solvent spinning pulp, high-strength spinning nozzles or spinning nozzle materials are required, as spinning pressures can rise up to 200 bar.

30 These problems are particularly pronounced in cellulose solutions prepared by the NMM0 method. This method is known, for example, from the examples mentioned in DE-A-29 13 589. In NMM0, N-methylmorpholine N-oxide, a tertiary amine N-oxide, which is a solvent for cellulose, is used.

2,92845

Due to the high spinning viscosity, the spinning nozzles in use must be equipped with reinforced spinning plates.

On the other hand, the aim is to increase the density of the ka-5 pillars of the spinning nozzles in order to increase the efficiency of the surface units of the spinning points. But then a problem arises that the fibers tend to stick together.

In order to nevertheless increase the density of the capillaries, the adhesion of the fibers must then be reduced. It can be carried out by applying an insoluble liquid to the surface of the freshly extruded fibers, which reduces the effect of the solvent (cf. DE 28 44 163). In addition, according to the tertiary amine oxide, a polyalkylene ether, in particular poly-15 ethylene glycol, can be added (cf. DD patent publication 218,121).

Thus, a spinning nozzle with a relatively large diameter and a high capillary density and a consequent large number of capillaries is needed to spin the cellulose solution economically. At the same time, the Keh-20 rose nozzles must withstand high pressures, up to 130 bar.

Although known spinning nozzles have a partially high capillary density, they do not withstand high spinning pressures: the spinning plate bends or tears. Such nozzles are used in viscose processes.

On the other hand, spinning nozzles are known which are made of special high-grade steel types. Such spinning nozzles are used in dry spinning processes for plastic melts. This nozzle construction 30 again has the disadvantage that in the complex making of nozzle holes in the nozzle plate, a pre-hole must first be made for each spinning capillary in a relatively hard but strong material in order to make thin capillaries. If it is necessary to make pre-holes with a larger diameter than 35, fewer spinning capillaries are obtained for one nozzle plate, which results in a lower capillary density.

It is an object of the present invention to provide a spinning nozzle which, on the one hand, withstands high spinning pressures and, on the other hand, has a high capillary density (capillaries / mm 2).

According to the invention, this object is achieved by a spinning nozzle, characterized in that the holes in the support plate are stepped bores, the stepping being in the vicinity of the outer surface of the support plate and having a smaller diameter towards the outer surface of the support plate.

Thus, according to the invention, a support plate is used, the strength of which can be dimensioned large enough to withstand high spinning pressures. It can also be made of the desired strong material, since it itself does not have spinning capillaries. Small plates, e.g. precious metal plates, are inserted or pressed into the holes in the support plate, into which, depending on the softness of the metal, the required number of spinning capillaries can be made relatively simply without pre-holes.

The holes in the support plate are in particular stepped bores, the stepping being close to the outer surface of the support plate and the smaller diameter being on the outer surface of the support plate. Thus, the inserted or pressed small plate is held in place and can withstand quite high spinning pressures.

Finally, it is expedient if there is a perforated plate inside the support plate and a filter between the support plate and the perforated plate. The holes in the perforated plate are then arranged according to the holes in the small plate in order to distribute the cellulose solution or the polymer melt accordingly. The filter separates dirt particles and insoluble polymer particles.

Preferred embodiments of the spinning filter according to the invention appear from the appended dependent claims 2 and 3.

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The invention will be explained in more detail with reference to the accompanying figures, in which Figure 1 shows a sectional view of a spinning nozzle according to the invention; Fig. 2 shows the spinneret support plate of Fig. 1, in a slightly enlarged form with respect to Fig. 1, in partial section; and Fig. 3 shows a small plate to be inserted into the support plate according to Fig. 2, in a form enlarged in relation to Fig. 2, in partial section.

The nozzle head 1 (Fig. 1) is suitably made of corrosion-resistant stainless steel. It has a channel 6 for tempering and forms the top of a spinning nozzle into which the cellulosic solution is fed and which is continuously heated during spinning. A hole plate 3, a filter 4 and a support plate 2 are placed in the nozzle end 1. These three elements are pressed by the nut 5 into the nozzle end 1. A soft seal can be used as a seal (not shown).

The support plate 2 (Fig. 2) has a plurality of stepped holes 7 (Fig. 2 shows only one hole 7 for simplicity). Small plates 8 made of a relatively soft material are pressed into these holes (Fig. 3). Several capillaries can be easily made densely for this soft material (only one capillary 9 is shown in Figure 3 for simplicity).

The holes in the perforated plate 3 are made in exactly the order in which they are in the support plate 2, there is a filter 4 between them. The filters 4 can - depending on the cellulose solution or the polymer melt - have quite different pore diameters and can be of different materials. Corrosion-resistant metal gauze is preferred. The spinning mass is distributed in the perforated plate 3, filtered, and then enters 35 holes 7, i.e. stepped bores, and from there into the capillaries 9 of the small plates 8.

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In the spinning nozzle made according to the invention, a high capillary density is achieved despite the high pressure resistance. Thus, for example, a spinning nozzle with a diameter of 45 mm and 1147 capillaries (= 0.72 capillaries / mm2) has been developed and is designed for an operating pressure of about 85 bar. The second spinning nozzle has 1.19 capillaries / mm2 and is designed for an operating pressure of approx. D55 bar.

The element-like structure of the nozzle package allows individual replacement of support plates with small stainless steel plates with capillaries of different diameters, lengths and cross-sections.

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Claims (3)

A spinning nozzle comprising a nozzle head (1) and a spinning plate comprising a very stable support plate (2), which is preferably made of precious metal and having heels (7) and in the heel provided or pressed small plates ( 8), wherein the small plates (8) comprise a plurality of capillaries, the plates (8) being made of a material which is less hardy than the support plate (2), preferably gold, silver or tantalum, characterized therein. the heel (7) of the support plate (2) is made of step bores, the steps being in proximity to the outer surface of the support plate and the smaller diameter being against the outer surface of the support plate (2), so that the small plate (8) abuts the steps. Spinning nozzle according to claim 1, characterized in that on the inside of the support plate (2) there is a heel plate (3) and that between the support plate (2) and the heel plate (3) there is a filter (4). 20 Spinning nozzle according to claim 1 or 2, characterized in that the nozzle head (1) comprises heating ducts (6) for tempering. • ·