DE1059611B - Device for spinning molten polyamides from vacuum chambers - Google Patents

Description

GERMAN

When spinning molten polyamides made from f-caprolactam, it is known to put the melt under vacuum before it is fed to the spinning unit in order to achieve certain levels in it constituents contained (e.g. in the case of polymers made from f-caprolactam, the monomers.) to be deposited and eliminate. The removal of certain components of the hot melt has the consequence that through the evaporation and the negative pressure within the melt form bubble cavities, so that Eventually the whole melt assumes a foamy state, which is particularly important for spinning when spinning the finest titre, is unsuitable, so that a vacuum-treated melt can be spinned again to make, it would have to be fed to a larger storage container, where it can be used in a suitable manner made bubble pulp and then fed to the spinning head with reheating. That has the disadvantage that by keeping the melt ready for a longer period in the molten state at elevated temperature Decompositions occur and new amounts of volatile substances that increase bubbles are formed continuously.

A device is known in which a separation of bubbles of the melt material with the help a horizontal screw conveyor with a strong progression, the one at the outlet end of the evacuation vessel is appropriate, takes place. Such a device has two disadvantages: one is the vacuum difficult to hold in the worm, since the shaft of the worm at least on the drive side in one Stuffing box must be guided. In addition, the bubbles in the melt rise horizontally stored snail only very slowly and incompletely upwards.

The invention relates to a device for spinning molten polyamides, which consists of 6-Caprolactam have been made from vacuum chambers consisting of one below a vacuum chamber vertically arranged, conically tapering downwards and in a tightly enveloping them Shell revolving worm, whose shaft with the shaft of a gear one below the Worm arranged, horizontally lying gear, wheel pump is coupled, as well as from one of the Underside of the conical screw to the suction hole of the pump and one of the pressure hole to the Spinneret leading channel.

With the help of this device you are able to • the spun material without intermediate storage during his Way to the spinning head not only from the disruptive, volatile components, but also from the in the vacuum chamber to eliminate the bubbles that often arise. The device according to the invention has the Another advantage that the vertically arranged device for spinning

of molten polyamides

from vacuum chambers

Applicant:

Farbwerke Hoechst Aktiengesellschaft

formerly Master Lucius & Brüning,

Frankfurt / M., Brüningstr. 45

Johann Wildegger, Bobingen near Augsburg,
has been named as the inventor

The screw does not have a special external drive and therefore no stuffing boxes are required. Through the clutch the worm shaft with the gear shaft is also guaranteed that the worm with is driven at the same speed as the gear pump. In addition, from the perpendicular arranged screw, which is in communication with the vacuum chamber, bubbles rise slightly.

To explain the device according to the invention, two examples are shown in FIGS. 1 and 2 Embodiments of the device shown schematically, to which reference is made below.

Fig. 1 shows an embodiment with a gear pump, while at

Fig. 2 two gear pumps are arranged one behind the other between the conical screw and the spinneret.

The device connects to one of the known vacuum chambers 1, in which, for example, the Melt from a nozzle 2 is pressed downward in coarse threads, under the action of the In the room 1 prevailing negative pressure from the molten threads 3, the monomers extracted and removed in a manner known per se. At the end of the path of the threads 3 through the Chamber 1, the threads, which are still molten, enter the corridors of a vertical, conical one downwardly tapering screw 4, which revolves in a shell 5 that surrounds it tightly. the The shaft of the worm 4 is connected to the shaft 7 of the coupling element 6, which can be designed in any way a gear of the two gears 8 and 9 arranged horizontally below the worm existing gear pump connected so that the

. :,; 909 557/360

Claims (2)

The worm is driven at the same speed as the gear pump. The molten threads 3, as soon as they come into engagement with the screw, are compressed in the progressively narrowing working space of the screw and thus already freed from the bubbles in them to a substantial extent. At the lower end of the working space of the screw, a sump of almost bubble-free polymer melt forms at a certain height, which is continuously pressed by the screw to the suction hole 10 of the gear pump 8, 9 and from this in a known manner to the through hole 11 of this pump is further promoted. (The two bores can be seen separately in the horizontal section of Figs. 1 and 2.) From the pressure bore 11, the melt passes into a pressure channel 12. While the melt in Fig. 1 is statically through this pressure channel to the spinning head 13 and the spinneret 14 is promoted, it loses the remainder of any bubbles left behind on the walls due to friction and pressure increase. In a further embodiment of the device according to the invention, as shown schematically in FIG. 2, not one, but two or more gear pumps are arranged one behind the other between the screw 4 and the spinning head 13 in a manner known per se. In this case, the melt flows through a channel 12 between the two gear pumps 8, 9 and 15, 16, which, when the pump 15, 16 is driven somewhat slower than the pump 8, 9, further pressurizes the melt and completely eliminates it of all bubbles compressed. After leaving the second gear pump, the melt enters the channel 17 and from there to the spinning head 13 and the spinneret 14. The figures show the gear pumps and screw approximately to scale in the correct proportions, while the vacuum chamber 1 is shown smaller than it actually is or . can be. The whole apparatus is shown in section through the central axis, but the screw is not cut, but shown in a vertical side view. The vacuum chamber and the spinning head are shown purely schematically, i. That is, they show, purely schematically, known components of the melting apparatus, which all elements known in this context may have, even if they are detailed, such as, for. B. the spinner head filter, are not shown. The device is completely vacuum-tight because the screw used to compress the vesicular melt does not require a special drive from the outside, the introduction of which into the negative pressure space would present considerable technical difficulties. The trick of coupling the worm shaft with the one gear shaft of the spinning pump means that the removal of bubbles can be carried out in a unit that is just as vacuum-tight as the previous devices with a minimal additional expenditure of force. Patent claims: 1. Device for spinning molten polyamides made from ε-caprolactam from vacuum chambers with deposition of volatiles, characterized by a below the vacuum chamber (1) arranged vertically, conically tapering downwards and a screw (4) revolving around it in a tightly enveloping jacket, the shaft of which coincides with the shaft of the one gear of a horizontally located gear pump arranged below the worm (8, 9) is coupled, as well as by one of the underside of the conical screw (4) to Saugboforung (10) of the pump and one of the Pressure bore (11) to the spinneret (14) leading channel (12). 2. Apparatus according to claim 1, characterized in that between the conical screw (4) and the spinneret (14) several gear pumps are arranged one behind the other. Considered publications:
German Patent Nos. 871 352, 742 867;
Swiss patent specification No. 294 346. 1 sheet of drawings © 909 557/360 6.59