DE1210965B - Method and device for sealing the thread exit opening of a spinning shaft during dry spinning - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

DOId

DeutscheKL: 29 a -6/06

Number: 1210 965

File number: P 32008 VII a / 29 a

Filing date: June 14, 1963

Opening day: February 17, 1966

When dry spinning threads made of high polymers, e.g. B. made of polyacrylonitrile or copolymers or copolymers of acrylonitrile, in which the spinning solution is passed through a nozzle into a spinning shaft presses, the solvent is usually removed from the spinning solution by a stream of hot gas or air evaporated, which z. B. flows through in the direction of the thread bundle. When the The thread bundle from the shaft should remove the solvent from the threads as much as possible to facilitate recovery of residual solvent and solvent losses to be avoided whenever possible.

Such losses can also occur when solvent-enriched air passes through the opening at the end of the shaft with the bundle of threads. This opening must not be chosen too small so that especially when spinning a large number of several hundred capillary threads, some of them still Do not stick moist single threads to the wall of the hole. However, if you choose the outlet opening for If the thread bundle is sufficiently large, it is necessary to apply a vacuum of several at the end of the shaft Maintain millimeters of water to prevent solvent vapors from escaping with certainty to prevent. However, this has the consequence that a not insignificant amount of false air in the spinning gas cycle occurs, which reduces the concentration of the solvent vapor in the circulating mixture and increased equipment and operational expenditure for solvent recovery makes necessary. This also applies if the thread bundle is passed through a tube in a known manner leads out of the spinning shaft.

Particularly disadvantageous is the ingress of air at the thread exit in systems that use the Cool the steam-air mixture in a closed circuit, removing the solvent as much as possible remove and then, after reheating, introduce the mixture again into the spinning shaft. Such a mixing ratio of solvent with air can be established in the spinning shaft, that the lower explosion limit is exceeded. For this reason one is forced into the circulating Mixture of solvent vapor and air as an inert gas, such as nitrogen or carbon dioxide Introduce protective gas.

There would now be no leakage in the entire circuit and no possibility for air to penetrate from the atmosphere, the consumption of protective gas would be extremely low in order to reduce the oxygen content of the circulating mixture in the spinning process and device for sealing the thread outlet opening of a spinning shaft in Dry spinning

Applicant:

Phrix-Werke Aktiengesellschaft,

Hamburg 36, Stephansplatz 10

Named as inventor:

Dr. Alfred Friederich, Hamburg-Hochkamp

the shaft below the critical limit, which can lead to explosions. On the other hand, they have the openings in the shaft, especially at .Fadenaustritt, a larger diameter, and prevails in the shaft Even at this point there is a significant negative pressure, so it is difficult or even impossible to find the critical To fall below the level of the oxygen content in the shaft.

The aim of the invention is to close the thread outlet opening of the spinning shaft during dry spinning Seal circulating solvent vapor-air mixture to prevent penetration to avoid air and the loss of solvent at the thread exit of the spinning shaft and also to reduce the consumption of this to a minimum when operating with protective gas. Achieved this is achieved according to the invention in that the thread outlet opening is continuously supplied with a barrier liquid which emerges together with the thread bundle. The thread bundle is so at the end of the shaft passed through a liquid seal to the outside, in such a way that all capillary threads from the liquid are enclosed. This makes it possible to block the passage, i.e. H. the thread outlet opening of the shaft to hold comparatively tight without the capillaries sticking to one another or sticking takes place on the wall of the thread passage.

It is expedient that the amount of the fed into the thread passage of the spinning tube in the unit of time Liquid corresponds to the amount of liquid that the thread bundle carries with it and on its Surface so that no liquid escapes freely downwards, the cross-sectional area of the Outlet opening of the thread passage organ so

■, - ·. ' . "'609 508/189

is placed that the spinning shaft is still after is sealed on the outside. "As a barrier fluid, it is advisable to use water other liquids into consideration as long as they are not a solvent for polyacrylonitrile and with water are miscible, e.g. B. glycerine, glycols, glycol ethers and the like -. '■■ "

The one used to carry out this procedure According to the invention, the device consists of a 'liquid passage' inserted tightly into the shaft bottom forming organ, preferably in the form of a funnel, a liquid supply line and from a shut-off and regulating device for the sealing liquid.

A possible embodiment of the device is shown in the schematic drawing, in which the lower part of a spinning shaft 1 can be seen. With 2 the outlet nozzle is referred to, through which the solvent vapor-air mixture, which, as already mentioned, an inert gas as a protective gas may be admixed, is sucked off. The mixture exiting at 2 is after removal of the solvent fed back to the shaft at the top. The facilities required for this cycle are not shown in the drawing. A funnel 3 is inserted tightly into the shaft bottom, the in the example shown as a passage for the thread bundle 4 and that fed through the line 6 Water serves. By means of the shut-off and regulating device 5, the funnel 3 is continuously fed Measure the amount of water so that all liquid is retained by the emerging bundle of threads and no excess water will freely run out of the funnel.

Although the water the individual capillary threads from sticking together and sticking to each other protects the wall of the funnel, you can make the funnel made of a fluorocarbon resin for increased safety, z. B. polytetrafluoroethylene, which is particularly anti-adhesive. The string- and the passage of the liquid in the shaft does not, of course, have to be designed as a funnel. Man can also be used for this purpose z. B. od a pipe with attached water inlet. Like. Provide.

example

A spinning solution of 25% polyacrylonitrile in dimethylformamide is produced from a spinneret with 200 openings pressed into a spinning shaft 300 mm in diameter. In direct current with the threads a heated gas mixture with less than 10% oxygen, the rest inert gases, flows through the shaft downwards and enters the suction opening 2. The

The total weight of the thread bundle (solvent-free) is 50 g / min, the take-off speed from the spinning shaft is 300 m / min. The solvent content of the thread bundle when it enters the funnel 3 is 15%, based on dry weight. The diameter of the funnel 3 at the outlet end is 4 mm, the water speed 3 m / min and accordingly the amount of water exiting through the line 6 is around 37.5 cm ³ / min or 75% of the dry thread weight.

Claims (6)

Patent claims: 1. Method for sealing the thread outlet opening of a spinning shaft during dry spinning of threads made of high polymer materials, in particular made of polyacrylonitrile or co- or Mixed polymers, with at least 80% acrylonitrile, in which the spinning solution through a spinneret is pressed into a spinning shaft and at or near one end thereof for removal of the Solvent, a hot gas or air stream is introduced, which preferably the spinning shaft flows through in the direction of the thread bundle formed and at the other end of the shaft, loaded with solvent vapor, exits, characterized in that. the thread exit opening barrier liquid is continuously supplied, which emerges together with the thread bundle. 2. The method according to claim 1, characterized in that the amount of in the time unit the liquid supplied to the passage corresponds to the amount of liquid which the thread bundle and holds on to its surface. 3. The method according to claim 1 or 2, characterized by the use of water as Barrier fluid. 4. Apparatus for carrying out the method according to claims 1 to 3, characterized through one which is inserted into the bottom of the spinning shaft (1) and serves as a liquid passage Organ, a liquid feed line (6) and a shut-off and control element (5) for the barrier liquid. 5. Apparatus according to claim 4, characterized in that the liquid passage member is a funnel (3). 6. Apparatus according to claim 4 or 5, characterized in that the liquid passage or the funnel (3) made of a fluorocarbon resin, e.g. B. polytetrafluoroethylene. Considered publications:
U.S. Patent No. 1942,540. 1 sheet of drawings 609 508/189 2.66 © Bundesdruckerei Berlin