EP0937791B1 - Process and apparatus for the spinning of a multifilament yarn - Google Patents

Description

The invention relates to a method for spinning a multifilament yarn according to The preamble of claim 1 and a spinning device according to the The preamble of claim 11.

Such a method and apparatus are disclosed by the US 4,277,430 known.

In the known method and the known device is a on a Spinneret emerging filament bundle cooled by a cross-flow blowing. Below the cross-flow blowing, the cooling shaft is a second section extended. In the entrance area of the lower cooling shaft becomes an air / water mixture initiated as mist-like cooling flow into the cooling shaft, which by means of a suction in the thread running direction for cooling the thread flows to the end of the cooling section. This is due to the admixture of Liquid reaches a higher cooling effect on the filaments. The known However, the method has the disadvantage that a significant proportion of air from the Cross-flow blowing is introduced directly into the lower cooling shaft. Thereby An air flow surrounding the filament forms, which prevents Liquid particles reach the surface of the filament.

Furthermore, methods and devices are known in which at higher Thread speeds the cooling of the filaments by one with high Speed to be cooled in the cooling duct flowing airflow, like for example, in EP 0 244 217 or WO 95/1540 is described. However, such methods basically have the disadvantage that no intensive cooling of the filaments takes place. These methods are particular suitable for threads with relatively fine titer. In addition, the known lead Process to a pronounced hot drawing, which is an orientation of the Has molecules within the filaments result.

Accordingly, it is an object of the invention, a method and an apparatus for spinning a multifilament yarn of the type initially known in such a way educate that the thread cooled without significant preorientation can be.

This object is achieved by a method with the features according to claim 1 and by a device with the features according to Claim 11 solved.

The invention is characterized in that the countercurrently in the second Cooling zone initiated moist cooling flow to a high degree of wetting the Filaments leads, so that a relatively large amount of heat dissipated in a short time can be. It has surprisingly been found that the cooling stream flowing against the thread running direction does not become a substantial one Increasing the frictional resistance of the thread leads. On the contrary, the Counter-current can be adjusted so that no protective sheath in the form of a Air flow around the filament could form. The preferably from an air / liquid mixture existing cooling flow prevented the formation of a such protective jacket and led to an intensive cooling of the filaments.

Another advantage of the invention is that the uniformity of the Filaments is given by the fact that in the first cooling zone directly below the Spinneret is precooled by an air flow. Through this Precooling solidifies a boundary layer of the filaments, providing sufficient stability in order in the second cooling zone with the air / liquid mixture in To contact.

The method according to the invention and the device according to the invention are particularly suitable for producing high-strength filaments made of polypropylene. Such threads must be cooled with the least possible orientation be to the highest possible draft in the subsequent To obtain draw zone. The stretching takes place here advantageous over several galette pairs. By the invention it is achieved that such threads be produced with a winding speed of up to 5,000 m / min can.

The process variant according to claim 2 is particularly suitable to a uniform cooling of the filaments within the filament bundle receive. This allows pre-cooling of threads with a titer of up to 2,000 dtex Then, with an intensive cooling through the air / Cool liquid mixture without significant preorientation. moreover the suction of the air flow of the first cooling zone has the advantage that the Cooling flow of the second cooling zone is substantially unaffected and thus to an intensive and uniform cooling of the filaments leads. In addition, will prevents the flow of air from the first cooling zone into the second cooling zone arrives.

It has been shown that a sufficient pre-cooling already at a Cooling distance of <1 m, preferably <0.5 m, is achieved. This can be the Airflow through an inflator or through a self-priming depending on Create thread type and thread titer. Self-priming has the advantage that immediately below the spinneret a very weak air flow is formed, which leads to a very even thread titer. On the other hand has the blowing the advantage that the filaments within the filament bundle are relatively uniform be cooled.

The cooling stream used is preferably an air / liquid mixture. there the mixing ratio can be chosen such that a saturated or An unsaturated moist air is created. When using a saturated moist air has the advantage that a high liquid content to a intensive cooling of the filaments leads. Such a mixture is used in particular for large thread tiers. For threads with small titer On the other hand, it is preferable to use unsaturated moist air. Here is the Moisture content of the air regularly monitored, for example by a Dewpoint.

In a particularly advantageous variant of the method according to claim 7 of Cooling generated by blowing at the end of the second cooling zone, wherein the air flow of the blowing the liquid by means of a spray nozzle is added. As a result, in particular in the lower section of the second Cooling zone causes a very intense cooling of the filaments.

The process variant according to claim 8 is particularly good for the production of suitable for technical yarns. Here, the cooling flow through a suction generated, wherein an airflow generated by the suction, the liquid is added at the end of the cooling zone by means of a spray nozzle.

However, it is also possible to enrich the air with moisture in one Climatic chamber perform. The moisture content of the air can be very high be precisely adjusted and regulated, so that when using multiple spinning stations an air stream with the same moisture content is available at each spinning station.

To ensure a uniform distribution of the liquid within the To obtain cooling flow is the development of the method according to claim 9 particularly suitable.

The liquid used in the process according to the invention is preferably water.
The spinning device according to the invention is characterized in particular by the fact that the cooling device has two cooling zones whose cooling effect is independently adjustable and controllable.

To the air / liquid mixture in the cooling flow of the lower cooling shaft to produce, is the formation of the spinning device according to claim 12 especially beneficial. Here is one already generated in the cooling shaft Air stream, the liquid in the finest drops added. That's how the liquid gets promoted by a metering pump at high pressure through a spray nozzle. In this way, a fog-like cooling flow, the counter to thread running direction flows.

To ensure a high uniformity of the distribution of the liquid within the To achieve cooling flow, the formation of the atomizer nozzle according to claim 13 especially cheap.

However, it is also possible to get a favorable distribution of the atomized To obtain liquid, several atomizer nozzles in the cooling shaft of the second To arrange cooling zone.

An advantageous embodiment of the spinning device according to claim 15 especially with annular spinnerets advantage. This will do that Filament bundles in both the upper cooling shaft and in the lower Cooling shaft cooled evenly. In particular, by the closed Pipe in the lower part of the cooling device, the cooling air flow as close as possible be brought to the filament bundle.

The formation of the spinning device according to the invention according to claim 16 offers the advantage that the filaments within the filament bundle evenly be cooled.

In a particularly advantageous embodiment of the invention according to claim 17, the extracted cooling stream is treated so that the liquid from the Air flow is separated and discharged to a container. For this is the Suction device connected to a water separator. Out of the container can then supply the metering pump, so that a fluid circuit arises.

Another particularly advantageous embodiment of the spinning device according to Claim 19 is particularly suitable to the upper cooling shaft a self-priming cooling of the filaments. The for cooling the Filaments generated air flow is in this case essentially by the below set the cooling duct arranged suction.

With reference to the accompanying drawings, some embodiments of the Spinning device according to the invention and advantageous effects of inventive method described in more detail.

Fig. 1

schematisch eine erfindungsgemäße Spinnvorrichtung zum Spinnen eines multifilen Fadens;

Fig. 2 und 3

weitere Ausführungsbeispiele einer Kühleinrichtung einer Spinnvorrichtung aus Fig. 1.

They show:

Fig. 1

schematically a spinning device according to the invention for spinning a multifilament yarn;

FIGS. 2 and 3

Further embodiments of a cooling device of a spinning device of FIG. 1.

In Fig. 1, a spinning device according to the invention for producing a multifilament yarn is shown schematically. In this case, a thermoplastic material is fed via a melt feed 1 to a spinning beam 2. The thermoplastic material could in this case be supplied directly from an upstream extruder or from a pump.
On the underside of the spinneret 2, a spinneret 3 is arranged. The spinning beam 2 usually carries a plurality of preferably arranged in series spinnerets. Each of the spinnerets constitutes a spinning station of the spinning device. Since a thread is produced in each spinning station, only one spinning station is shown in FIG.

From the spinneret 3, the melt emerges in the form of fine filament strands, which form a filament bundle 4. The filament bundle 4 passes through one below the spinneret 3 arranged cooling shaft 6. The cooling shaft 6 is a through air-permeable tube 9 is formed. For this purpose, the tube has a plurality of transverse bores. It could, however, be made of an air-permeable be made porous sheath. The tube 9 is in a blower 11 a Blowing device 10 is arranged. In the blower 11 is an air flow generated by a blower 12. For this purpose, the blower 12 with an inlet 16th connected. About the inlet 16 can conditioned air of an air conditioner or but also the ambient air is sucked in.

Below the upper cooling shaft 6 is another cooling shaft 7 through a Tube 13 is formed, which is traversed by the filament bundle 4. Between the Pipe 9 and the pipe 13, a suction device 8 is arranged. The Suction 8 is here by an annular, the filament bundle enclosing suction chamber 15 and connected to the suction chamber 15 Blower 14 is formed. The inner wall of the suction chamber 15 is also permeable to air, so that an air flow discharged from the cooling shaft 6 and 7 can be. For this purpose, the suction device 8 an outlet 17.

The tube 13 has a closed jacket. In the area of the free end of the tube 13, a spray nozzle 18 is attached to the circumference of the tube 13. The Atomizing nozzle 18 has a nozzle opening 21 in the interior of the tube 13 is directed. The atomizer nozzle 18 is at the pressure line of a metering pump 19 connected, which is connected via a suction line with a container 20. At the end of the cooling shaft 7, the filament bundle 4 outside of Cooling shaft 7 through a preparation device 22 to a thread. 5 summarized and provided with a preparation liquid. The thread 5 occurs then in a drawing zone. Here, the thread 5 from the cooling shaft 6 and 7 and deducted from the spinneret 3 by a Abzugsgalette 23. Of the Thread wraps around the withdrawal godet 23 several times. Serves one entangled to the godet 23 arranged overflow roller 24. The overflow roller 24 is freely rotatable. The godet 23 is driven by a drive (not shown here) and with operated at a presettable speed. This take-off speed is many times higher than the natural exit velocity of the Filaments from the spinneret 3. The withdrawal godet is followed by a drafting field several godets. Here are for example two Galettenduos with the Galettes 25.1 and 26.2 as well as a pair of galettes with 25.2 and 26.2 are shown.

From the last draw godet 25.2 the thread 5 runs in a take-up device 27. The take-up device 27 has a head thread guide 28, which the Forming the beginning of a so-called traversing triangle. The thread 5 then runs in a traversing device 32, wherein the thread by means of guide elements along a traverse stroke is led back and forth. The traversing device 32 is as a Kehrgewindewalze with a guided traverse guide or executable as Flügelchangiereinrichtung. From the traversing device 32 is running the thread via a contact roller 41 to the coil to be wound 29. Die Contact roller 41 rests on the surface of the coil 29. It is used for measurement the surface speed of the coil 29. The coil 29 is on a Winding spindle 30 clamped. The winding spindle 30 is rotatable on a frame 31 stored. The winding spindle 30 is driven by a spindle motor (not shown here) driven so that the surface velocity of the coil 29 is constant remains. For this purpose, the controlled speed is the speed of the freely rotatable contact roller 41 sampled and corrected by the spindle motor.

In the spinning apparatus shown in Fig. 1, the filaments 4 after the Leakage from the spinneret 3 cooled by an air flow, by means of the Blowing 10 is directed radially circumferentially on the filament bundle 4. As a result, first enters a pre-cooling of the filaments, which solidify an edge layer of the filaments leads. The air flow is through the current Filaments substantially entrained and below the cooling shaft 6 through sucked the suction device 8 and discharged. Go through the filaments 4 then the lower cooling shaft 7. In the lower cooling shaft 7 flows Cooling flow counter to the thread running direction to the suction device 8. This Cooling flow is generated by the suction device 8, the ambient air in the cooling duct at the lower end of the tube 13 sucks. The one in the bottom Area of the tube 13 incoming air flow is by means of the spray nozzle 18th mixed with a liquid in the form of very fine droplets. This air / Liquid mixture is now due to the suction effect of the suction 8 against the thread running direction. This is an intensive cooling the filaments 4. The addition of the liquid is a relatively large Heat transfer generated so that the filaments without a substantial Orientation occurs, cooled. The cooling flow can be adjusted in this case are that, surprisingly, no significant frictional forces on the thread attack or the frictional forces have no due to the rapid cooling negative effect. The thread 5 thus occurs essentially unoriented in the subsequent stretching field. Through the godets 25 and 26 is a complete Drawing of the thread, which is then wound into a bobbin becomes. The inventive method allows Aufwickelgeschwindigkeiten of up to 5,000 m / min. By this high Winding speeds, for example, in the production of Polypropylene yarns production performance can be significantly increased.

In the cooling device has been shown that the first cooling zone with the Cooling shaft 6 already at a length of 0.1 to 0.5 m to solidify the Edge zone leads, which allows a subsequent liquid cooling of the filaments without deterioration of the uniformity of the filaments. The first cooling zone should, however, if possible be formed in the range of a length of 0.1 to 1 m be. In the second cooling zone, the cooling effect is substantially of the Proportion of the liquid in the cooling flow dependent. The proportion of the liquid is but primarily dependent on the fineness of the liquid mist.

The inventive method is not limited to the production of filaments made of polypropylene. It can also threads according to this method made of polyamide or polyester. Likewise, the in Fig. 1 shown stretching zone only one example of a treatment of a thread. In Dependent on the thread type, the treatment can be done after removing the thread from the spinneret by stretching, heating, relaxing or swirling be supplemented or replaced. It is also possible to use the spinning device to operate galettenlos. Here, the thread by means of a Winding device withdrawn directly from the spinneret.

In Fig. 2 is another embodiment of a device for cooling the filaments, as used for example in the spinning device of FIG. 1 could be used shown. Here, in turn, the first cooling zone through the Tube 9 and the second cooling zone formed by the tube 13. The tube 9 is on one side with a blow chamber 33, a blowing device 32 is connected. The Blowing device 32 is designed as a so-called Querstromanblasung. in this connection By a fan 34, a cooling air flow through an inlet 35 in the Blaskammer 33 out. In the region of the blow chamber 33, the air flow passes through the air-permeable pipe wall on one side within the cooling shaft 6 a. The Filaments are thereby precooled. As already shown in Fig. 1, the Suction device 8 between the tube 9 and the tube 13 is arranged.

Compared with the suction device shown in Fig. 1, the Suction device of FIG. 2 a connection to a water separator 36th Here, the extracted cooling flow from the lower cooling shaft 7 of Blower 14 led to the water. In the water separator takes place Separation between the gaseous and the liquid components of the Cooling stream. The gaseous components of the cooling stream are from the Outlet 17 discharged. The liquid components become a container 20 guided. The container 20 simultaneously serves to supply the metering pump 19, which feeds the atomizing nozzle 18 in the lower region of the cooling shaft 7. These Arrangement has the advantage that the introduced liquid in the cooling stream continuously regenerated and fed back to the cooling stream.

In the cooling device shown in Fig. 2 is in the exit region of the Cooling shaft 7, the spray nozzle 18 is formed such that several Nozzle openings are arranged radially circumferentially on the circumference of the tube 13. This ensures that the atomized liquid is very uniform in the Airflow distributed. The air flow is here by a at the output of the lower Cooling shaft 7 arranged blowing device 37 generates. For this purpose, the Blower 37 an air inlet 40, a blower 39 and a blow chamber 38 on the blow chamber 38 is connected to the cooling shaft 7 permeable to air. The blow chamber 38 is annular in this case, so that an air flow radially flows into the cooling shaft 7. By this design of the cooling device leaves the cooling of the filaments intensify even further.

Another embodiment of a cooling device is by modification given the spinning device shown in Fig. 2. This will be the end the cooling tube 13 arranged blowing device 37 with the air inlet 40 at connected to a chamber. In this chamber will be one Air / liquid mixture with a certain moisture content of the air produced. The moist air is sucked out of the chamber by the blower 39 and blown into the blow chamber 38. From the blow chamber 38 passes the humid Air through the negative pressure generated in the pipe 13 as a counterflow on the Filaments. Direct introduction of liquid through the atomizer nozzles 18 is not required in this case. The atomizer nozzles could, for example be arranged in the chamber to a saturated or an unsaturated moist To generate air.

In Fig. 3, another embodiment of a cooling device is shown as they are used, for example, in a spinning device according to FIG. 1 could. In the device shown in Fig. 3, the suction device between the upper cooling shaft 6 and the lower cooling shaft 7 through two Building units 8.1 and 8.2 formed. The unit 8.1 is connected to the tube 9 of connected to the first cooling zone. The tube 9 is on the entire circumference permeable to air. Thus, by the suction 8.1 Air flow generated, which enters radially from the outside into the cooling shaft 6 and over the Blower 14.1 and the outlet 17.1 is discharged. In this arrangement exists the advantage that directly below the spinneret, a relatively weak Airflow forms. This weak air stream favors the cooling of the Filaments such that a uniform solidified shell zone at the Forms filaments. Directly below the spinneret 3 are the exiting Filaments 4 still molten, so that a strong air flow on an influence the uniformity of the filament strands has. This arrangement is thus particularly suitable for such types of polymers, in which a slow Pre-cooling of the filaments in the first cooling zone is desired. Below the first cooling zone, the second cooling zone is formed with the tube 13. The pipe 13 is in this case arranged with its upper end to the suction 8.2. As already shown in the cooling device in Fig. 2, the suction device 8.2 coupled from Fig. 3 with the water separator 36. In that regard, on the Description taken to Fig. 2 reference.

In the embodiment shown in Fig. 3, however, the cooling flow in Cooling shaft 7 exclusively generated by the suction 8.2. At the end of the tube 13, a plate 43 is arranged. The plate 43 has an opening 42, through which the filament bundle exits. This embodiment has the Advantage that generates an aligned in the center of the cooling shaft 7 air flow becomes.

The atomizer nozzle shown in Fig. 3 is annular, so that the Orifice radially circulating the liquid evenly in through the Injecting opening 42 incoming airflow.

LIST OF REFERENCE NUMBERS

1

melt feed

2

spinning beam

3

spinneret

4

Filaments, filament bundles

5

thread

6

cooling shaft

7

cooling shaft

8th

suction

9

pipe

10

blowing device

11

blowing shaft

12

fan

13

pipe

14

fan

15

suction

16

Inlet

17

outlet

18

atomizer

19

metering

20

container

21

nozzle opening

22

preparation device

23

godet

24

Guide roll

25

godet

26

Guide roll

27

takeup

28

Yarn guide

29

Kitchen sink

30

winding spindle

31

frame

32

blowing device

33

puffer

34

fan

35

Inlet

36

water

37

blowing device

38

puffer

39

fan

40

Inlet

41

contact roller

42

opening

43

plate

Claims (19)

1. Method of spinning a multifilament yarn of a thermoplastic material, wherein the thermoplastic material is extruded through a spinneret to a filament bundle with a plurality of filaments, wherein the filament bundle is cooled before being combined to a yarn, and wherein cooling occurs substantially in two cooling zones, the filaments being cooled in a first cooling zone by an air stream transverse of the direction of the advancing yarn and in a second cooling zone by a cooling stream of moist air, characterized in that the cooling stream in the second cooling zone is generated independently of the air stream in the first cooling zone, and that for cooling the filament bundle the cooling stream flows inside the second cooling zone in opposite direction to the advancing yarn.
2. Method of claim 1, characterized in that the air stream in the first cooling zone is supplied to the filament bundle over its entire circumference crosswise to the direction of the advancing yarn, and that the air stream is sucked off at the end of the first cooling zone.
3. Method of claim 2, characterized in that the air stream is supplied substantially uniformly to the filament bundle over a cooling length smaller than 1 m, preferably smaller than 0.5 m.
4. Method of claim 2 or 3, characterized in that the air stream is generated by blowing.
5. Method of claim 2 or 3, characterized in that the air stream is generated by self-aspiration.
6. Method of one of claims 1-5, characterized in that the cooling stream consists of saturated moist air (mist) or unsaturated moist air, and that the moist air is uniformly supplied at one or more points of the cooling zone.
7. Method of one of the foregoing claims, characterized in that the cooling stream is generated by blowing at the end of the second cooling zone, a liquid being added by means of an atomizer nozzle to an air stream generated by blowing.
8. Method of one of claims 1-6, characterized in that the cooling stream is generated by suction, the liquid being added at the end of the cooling zone by means of an atomizer nozzle to the air stream generated by suction.
9. Method of claim 8, characterized in that the second cooling zone is divided into two sections, and that between the two sections the atomized liquid is supplied to the cooling zone, so that the cooling stream contains no liquid in one section at the end of the cooling zone.
10. Method of one of the foregoing claims, characterized in that the liquid consists preferably of water.
11. Spinning apparatus for producing a yarn (5) of a thermoplastic material with a spinneret (3) and a takeup device (27), as well as with a cooling device downstream of the spinneret (3) which comprises an upper cooling shaft (6) facing the spinneret (3) and a lower cooling shaft (7), whereby in the upper cooling shaft (6) the filaments are cooled directly below the spinneret by an air stream transverse of the direction of the advancing yarn and in the lower cooling shaft (7) by a cooling stream of moist air, characterized in that the cooling device comprises between the upper cooling shaft (6) and the lower cooling shaft (7) a suction device (8) that removes by suction the air stream from the upper cooling shaft (6) and the moist air stream from the lower cooling shaft (7).
12. Spinning apparatus of claim 11, characterized in that an atomizer nozzle (18) with a nozzle opening (21) is arranged within the cooling shaft (7) in the lower outlet region thereof, and that the atomizer nozzle (18) is connected to a metering pump (19) that connects to a tank (20).
13. Spinning apparatus of claim 12, characterized in that the nozzle opening (21) is made annular and surrounds the filament bundle (4) advancing through the cooling shaft (7).
14. Spinning apparatus of claim 12, characterized in that a plurality of atomizer nozzles (18.1; 18.2) are evenly distributed over the circumference of the cooling shaft (7) and surround the filament bundle (4) advancing through the cooling shaft (7).
15. Spinning apparatus of one of claims 11-13, characterized in that the upper cooling shaft (6) is formed by a peripherally air-permeable tube (9), that the lower cooling shaft (7) is formed by a peripherally closed tube (13), and that the tubes (9, 13) connect to the suction device (8).
16. Spinning apparatus of claim 14, characterized in that the tube (9) of the upper cooling shaft (6) is arranged substantially over the entire length inside an air shaft (11) of a blowing device (10).
17. Spinning apparatus of one of claims 12-15, characterized in that the suction device (8) connects to a water separator (36) that supplies the liquid separated from the suction stream to a tank (20).
18. Spinning apparatus of one of the foregoing claims, characterized in that at the outlet of the lower cooling shaft (7) a blowing device (37) is arranged which generates inside the lower cooling shaft (7) an air stream opposite to the direction of the advancing yarn.
19. Spinning apparatus of one of claims 11-17, characterized in that the suction device is formed by two independently controllable structural units (8.1, 8.2) that connect each to a cooling shaft (6, 7).

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