EP0826802B1 - Process and device for spinning multifilament yarns - Google Patents

Description

The invention relates to a method for spinning a multifilament thread a thermoplastic material and a device for cooling freshly spun Filaments made of a thermoplastic material according to the generic term of claim 1 and the preamble of claim 8.

A method and an apparatus of this type are known from US Pat. No. 4,909,976. After that, the filaments are left after leaving the nozzle plate and before cooled down to a thread. You will upon leaving out of the nozzle holes through a first cooling zone, a heating zone and then through led a second cooling zone. In this known method is already in the first cooling zone worked with a high cooling rate. After that the filaments in the heating zone are exposed to hot air exposed. After leaving the heating zone, the filaments are passed through the second cooling zone led where it the glass transition and solidification temperature to reach. The known method is intended to serve the structure and properties of plastic threads using the melt spinning process in the broadest sense to improve, especially the orientation and crystallinity.

With the extremely rapid cooling in the first cooling zone of the known method a lively air flow acts on the filaments at high speed on. These enter the first cooling zone in an almost molten state and are not just a big jump in temperature, but also exposed to the mechanical forces of the air flow. That must lead to irregularities cross-section of the filaments. This is the known method not suitable for the production of threads with great external uniformity should be. The subsequent application of hot air to the filaments brings with it mechanical stress and is therefore just as unfavorable like a harsh temperature change.

In contrast, it is an object of the invention to provide a method of the aforementioned Type and a device for cooling the filaments in this process to develop such that a thread with high uniformity and high Stretchability, d. H. Elongation at break, is produced.

Surprisingly, it has been found that this task in relation to the Method with the features of claim 1 and with respect to the device is solved with the features of claim 8.

In the method according to the invention, those emerging from the nozzle plate Filaments in the first cooling zone due to a weak flow of cooling air cooled that the filament skin solidifies first. It can no longer do so come that the molten filament flows away, d. H. Thickening or Forms dilutions. The heating of the filaments in the heating zone by illumination has the surprising effect that it protects the filaments, especially The mechanical stress on the filaments is also reduced because of the reheating the filaments are not made by airflow alone. In this gentle way, the thread in the heating zone is reheated, and to a temperature that is within the plasticizing range of the polymer lies, but below the solidification temperature. This will freeze the frozen ones Molecular chains broken up again, so that the mobility of the molecular chains leads to disorientation.

The inventive method has the advantage that the gentle Disorientation an increase in the elongation at break of the thread is achieved and a subsequent stretchability at a given take-off speed of the thread can be increased.

After further development of the method according to claim 2, the heating can the filaments in the heating zone are also made by blowing; the before mechanical stress on the filaments is then still reduced, because most of the warming is due to the spotlight.

Claim 3 is a particularly favorable one for many thermoplastic materials suitable temperature range is highlighted.

Claims 4 and 5 show advantageous options, such as the weak one Cooling air flow for the first cooling zone can be caused.

Claims 6 and 7 contain advantageous guides of the cooling air flow in the second cooling zone.

The advantages of the device according to the invention for cooling freshly spun Filaments according to claim 8 consist in the known three-part of the To maintain cooling section, but advantageous to modify that the Reheating the filaments in the heating zone by one to the Filament-directed radiant heater is made. This reduces the mechanical Strain on the filaments when heated also has a thermal effect gentle heating and is structurally easy to implement.

According to claim 9, the arrangement of the radiant heater is advantageous on both Side walls of the cooling shaft extended.

With the training according to claim 10, the possibility is shown that Filaments advantageously at least partially enveloped by the radiant heater.

With the arrangement according to claim 11, the advantage is also achieved that the radiant heater heats the returning cooling air.

If, according to claim 12, the upper side walls of the cooling shaft are also made, So the side walls of the first cooling zone, permeable to air, so you can the ambient air use for cooling in the first cooling zone. By a certain Arrangement of radiant heaters according to claim 13 can also be a Generate air flow in the desired manner.

The advantageous development in which the filament bundle is wrapped from the radiant heater leads to a particularly uniform heating of the Filaments.

In a preferred embodiment, the radiant heaters are heated Reflector plates arranged in the blow duct. It is advantageous here if an already warmed air flow is supplied by the cross-flow blowing becomes. Through the reflector plates, the through the filament bundle cooled air flow heated again and returned to the filament bundle. This ensures high uniformity of the heat treatment of the filaments causes.

Further advantageous process variants and further developments of the Devices are defined in the subclaims.

The following will refer to the attached drawings some embodiments explained.

Fig. 1

das Schema einer Spinnanlage mit Spinnzone I, Streckzone II und Aufwickelzone III zur Herstellung eines glatten Fadens;

Fig. 2

schematisch eine erfindungsgemäße Vorrichtung zum Kühlen der Filamente in der Spinnzone;

Fig. 3

einen Querschnitt durch einen Blasschacht mit Reflektorblech;

Fig. 4

ein Schema einer Vorrichtung zur Kühlung der Filamente in der Spinnzone.

Show it:

Fig. 1

the diagram of a spinning plant with spinning zone I, stretching zone II and winding zone III for the production of a smooth thread;

Fig. 2

schematically an inventive device for cooling the filaments in the spinning zone;

Fig. 3

a cross section through a blow duct with reflector sheet;

Fig. 4

a diagram of a device for cooling the filaments in the spinning zone.

In Fig. 1, a spinning system is shown schematically, which consists of a spinning zone I, a stretching zone II and a winding zone III. Here will the thermoplastic material through a filling device to the extruder 3 given up. The extruder 3 is driven by a motor 4. The motor 4 is controlled by a motor controller 8. In the extruder it will melted thermoplastic material. On the one hand, the Deformation work that is introduced into the material by the extruder. In addition, there is a heating device 5 in the form of a resistance heater provided, which is controlled by a heating controller 43. Through the Melt line passes the melt to the gear pump 9 through the Pump motor 44 is driven. The melt pressure before the pump will detected by the pressure sensor 7 and by feedback of the pressure signal the engine control 8 kept constant.

The pump motor is controlled by the pump controller 45 in such a way that that the pump speed can be adjusted sensitively. The pump 9 promotes the Melt flow to the heated spin box 10, on the underside of which the spinneret 11 is located in a nozzle pot 53. Exits from the spinneret 11 the melt in the form of fine filament strands 12. The Filament strands 12 pass through a cooling shaft 14 of a device for Cooling of the filaments. The device is vertically below the Nozzle plate 11 arranged. First, the filaments 12 pass through air-impermeable walls limited first cooling zone 46. That a heating zone 47 is then provided, in which the filament strands 12 can be heated by means of a radiator 52. After that is in the Device arranged a second cooling zone 48 in which a transverse to A stream of filaments directed through an air-permeable blower wall flows. For this purpose, the device is connected to an air supply 15.

At the end of the cooling shaft 14, the filament sheet is through a Preparation roller 13 combined into a thread 1 and with a Provide the preparation liquid. The thread 1 then enters the Stretching zone II. Here, the thread 1 from the cooling shaft 14 and withdrawn from the spinneret by a take-off godet 16. The string wraps around the trigger godet several times. For this purpose, one interlocks with the Galette 16 arranged overflow roller 17. The overflow roller 17 is free rotatable. The godet 16 is by the godet motor 18 and the Frequency generator 22 driven at a preset speed. This withdrawal speed is many times higher than the natural one Exit speed of the filaments from the spinneret 11. By Adjustment of the input frequency of the frequency converter 22 can The speed of the take-off godet 16 can be set. This will make the Pull-off speed of the thread 1 from the nozzle plate 11 is determined. The Discharge godet 16 is followed by a stretch godet 19 with a further overflow roller 20. Both correspond in their structure to the deduction godet 16 Overflow roller 17. The stretching motor 21 is used to drive the stretching godet 19 with the frequency transmitter 23. The input frequency of the frequency converters 22 and 23 is controlled by the controllable frequency generator 24 given. In this way, the frequency converter 22 and 23 individually the speed of the take-off godet 16 or the extending godet 19 can be set. The speed level of the trigger godet 16 and Plug-in godet 19, on the other hand, is collected collectively by the frequency converter 24 set.

From the stretch godet 19, the thread 1 runs into the winding zone III and there to the head thread guide 25 and from there into the traversing triangle 26. The thread then runs into a traversing device (not shown here), the thread by means of guide elements along a traverse stroke and brought here. The traversing device is as Reverse thread roller with a traversing thread guide or as Wing traversing device executable. The runs from the traversing device Thread over a contact roller 28 to the bobbin 33 to be wound Contact roller 28 lies on the surface of the coil 33. It is used for Measurement of the surface speed of the coil 33. The coil 33 is formed on a sleeve 35. The sleeve 35 is on a winding spindle 34 spanned. The spindle 34 is driven by the spindle motor 36 and Spindle control 37 driven such that the surface speed the coil 33 remains constant. For this purpose, the speed of the freely rotatable contact roller 28 on the contact roller shaft 29 by means of a ferromagnetic insert 30 and a magnetic pulse generator 31st sensed and corrected.

The method according to the invention for spinning a multifilament thread is not limited to the arrangement shown in FIG. 1. Basically is the method can also be carried out in such an arrangement in which the Stretch zone II has only one take-off godet. It is also possible that Spinning zone I can be operated directly with winding zone III, i.e. without godets.

2 shows a further exemplary embodiment of a device for Cooling of the filaments shown in the spinning zone. Just below the Nozzle plate 11 is a cooling shaft 14 receiving the filaments 12 Blow boxes 54 and 64 arranged on both sides are formed. Right away below the nozzle plate 11, the blow boxes 54 and 64 have the air-impermeable side walls 51 and 61. Sidewalls 51 and 61 form the first cooling zone. The first cooling zone depends on Polymer type and thread type have a length of approx. 250 mm to 500 mm.

Below the side walls 51 and 61 there are a plurality of radiant heaters 52.1, 52.2, 52.3 and 62.1 to 62.3 directed opposite to the filaments arranged. The radiant heaters 52.1 - 52.3 and 62.1 - 62.3 are included Distance to each other in the cooling shaft 14 parallel to Filament bundle 12 arranged so that an air inlet between the Radiant heaters in the cooling shaft 14 is possible. The radiant heaters point a surface temperature that is above 400 ° C. Below the The cooling shaft 14 becomes a radiant heater through air-permeable side walls 53 and 50 formed. The blow box 54 and the blow box 64 are each on an air supply 15 connected. The blown air now passes over the gaps between the radiant heaters 52.1 - 52.3 and 62.1 - 62.3 and through the air-permeable blowing wall 53 and 50 into the cooling shaft 14 inside. The preparation roller 13 is below the cooling shaft 14 arranged where the filament bundle 12 merged into a thread 1 becomes.

A cross section of the heating zone of a blow chamber 54 is shown in FIG. 3. Here, the filament bundle 12 passes through the cooling shaft 14 Cooling shaft 14 is limited by the side walls 57 and 58. The blowing chamber 54 with the blowing wall 53 is of such a type transverse to the filament bundle arranged that the inflowing air in the blow chamber 54 through the Blower wall flows across the filaments along side walls 57 and 58. Opposite the blower wall 53 on the opposite side of the A reflector plate 55 is arranged in the filament bundle. The reflector plate is heated by a resistance heating wire 56. This will be a direct one Heating of the filaments and heating of the cooling air flowing back generated.

4 is a further embodiment of a device for Cooling of the filaments shown in the spinning zone. Compared to that in FIG. 2 The arrangement shown is the side walls 51 and 61 of the cooling shaft 14 air permeable directly below the spinneret 11. Likewise, they are Radiant heaters 52.1 - 52.3 arranged on both sides of the filament bundle and 62.1 - 62.3 again arranged at a distance. This enables that the ambient air can flow into the blow duct and thus leads in particular to a better cooling effect in the first cooling zone. Here is below the first cooling zone 46 and the heating zone 47 Blow box 59 arranged. The blow box 59 is connected to the air supply 15 connected. The blow walls 53 and 50 are permeable to air, so that a Airflow from the blow chambers 59 and 60 across the filament bundle 12 in flows into the cooling shaft 14. Below the cooling shaft 14 is again a preparation device 13 is arranged to form the thread 1.

The second cooling zone 48 is high in the processes Withdrawal speeds are also advantageously designed such that a self-priming air flow is drawn into the blow duct 14. Here active blowing would be omitted.

Another advantageous development of the method is the variant in which the air flow is blown into the cooling shaft 14 from below and thus flows against the thread running direction.

With this method it has been shown that the elongation at break of the threads around > 5% is increased. The increase in stretchability increases accordingly also by> 5%.

REFERENCE SIGN LIST

1

thread

2nd

Filling device

3rd

Extruder

4th

engine

5

Heating device

6

Melting line

7

Pressure sensor

8th

Engine control

9

pump

10th

Spinning head

11

Nozzle / nozzle plate

12th

Filaments / bundles of filaments

13

Preparation roller

14

Cooler

15

Air supply

16

Deduction godet

17th

Overflow roller

18th

Drive motor

19th

Steckgalette

20th

Overflow roller

21

Drive motor

22

Frequency transmitter

23

Frequency transmitter, stretch ratio control

24th

Trigger control

25th

Head thread guide

26

Traverse triangle

28

Contact roller

29

Contact roller shaft

30th

ferromagnetic insert

38

Head thread guide

39

Incoming delivery plant

43

Heating control

44

Pump motor

45

Pump control

46

first cooling zone

47

Heating zone

48

second cooling zone

50

Blow wall / side wall

51

Side wall

52

Radiant heater

53

Side wall

54

Blow box

55

Reflector plate

56

Resistance heating wire

57

Side wall

58

Side wall

59

Blow box

60

Side wall

61

Side wall

62

Radiant heater

64

Blowing chamber

Claims (13)

1. Process for spinning a multifilament yarn (1) made of a thermoplastic material, in which the molten thermoplastic material is extruded through a plurality of nozzle holes of a nozzle plate (11) into filaments (12), in which the filaments (12) are cooled into a yarn (1) before being combined, wherein the filaments (12) are guided, on discharge from the nozzle holes through a first cooling zone (46), a heating zone (47) and then through a second cooling zone (48), characterised in that the filaments (12) in the first cooling zone (46) are initially cooled by a weak cooling air stream in such a way that the filament skin initially solidifies, are then heated by irradiation between the first cooling zone (46) and the second cooling zone (48) in the heating zone (47) and are then cooled again in the second cooling zone (48).
2. Process according to claim 1, characterised in that the filaments (12) are heated in the heating zone (47) by irradiation and blowing.
3. Process according to claim 1 or 2, characterised in that the irradiation is carried out by a radiant heater (52) adjusted to a temperature of at least 400°C.
4. Process according to any one of claims 1 to 3, characterised in that the filaments (12) are cooled until the filament skin sets in the first cooling zone (46) by a weak cooling air stream entering from the outside in.
5. Process according to claim 4, characterised in that the cooling air stream is produced by automatic suction or blowing.
6. Process according to any one of claims 1 to 5, characterised in that the filaments (12) are cooled in the second cooling zone (48) by a cooling air stream of blowing from the outside in or from the inside out.
7. Process according to any one of claims 1 to 5, characterised in that the filaments (12) are cooled in the second cooling zone (48) by a cooling air stream produced by automatic suction.
8. Device for cooling freshly spun filaments (12) made of a thermoplastic material, which is arranged perpendicular below a nozzle plate (11) and which has a cooling shaft (14) with a first cooling zone (46), a heating zone (47) and a second cooling zone (48), wherein at least a side wall of the cooling shaft (14) is divided into an upper side wall (51) in the region of the first cooling zone (46) and a lower side wall (53) in the region of the second cooling zone (48) and wherein the lower side wall (53) is air-permeable in design, characterised in that a radiant heater (52) directed to the filaments for irradiating the filaments is arranged between the upper side wall (51) and the lower side wall (53).
9. Device according to claim 8, characterised in that on both sides of the filaments (12) the side walls of the cooling shaft (14) are divided into upper side walls (51, 61) and lower side walls (50, 53) and in that at least one radiant heater (52, 63) is arranged in each case between the upper and lower side walls.
10. Device according to claim 8, characterised in that the radiant heater (52) is annular in design in such a way that the filaments are at least partially enveloped.
11. Device according to any one of the preceding claims, characterised in that the upper side wall (51) and the lower side wall (53) are connected to a blow chamber (54) in such a way that a cooling air stream can be blown from the outside in into the cooling shaft (14) and in that the radiant heater is designed as a heated sheet metal reflector (55).
12. Cooling device according to any one of claims 9 to 11, characterised in that at least one of the upper side walls (51, 61) is air-permeable.
13. Device according to any one of the preceding claims, characterised in that a plurality of radiant heaters (52.1, 52.2) are arranged together, in such a way that between the radiant heaters (52.1, 52.2) an air flow can be created into or out of the cooling shaft (14).

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