EP1710329B1 - Process and apparatus for meltspinning and cooling filaments - Google Patents

Description

The invention relates to a method for melt spinning and cooling a plurality of filaments according to the preamble of claim 1 and an apparatus for performing the method according to the preamble of claim 9.

In the production of spunbond webs, it is known that a plurality of filaments are extruded in a spinning device, cooled together as a filament curtain and deposited into a nonwoven web. For this purpose, usually deduction nozzles are used, which subtracts the filament curtain from the spinning device and leads to a arranged below the discharge nozzle storage belt. To cool the freshly extruded filaments, a stream of cooling air is blown across the filament curtain onto the filaments so that there is solidification of the filaments before entry into the draw-off nozzle. Such a method or device are for example from the US 6,183,684 known.

From the JP 56096908 An apparatus for melt-spinning thermoplastic synthetic fibers is known. In this device, an air stream is first passed horizontally to the spun filaments. In addition, the air flow is then deflected and discharged in the withdrawal direction of the filament together with them.

Furthermore, from the EP 0 671 492 A1 a wet spinning process for producing cellulosic moldings and a device for carrying out the process known. In this case, for the preparation of cellulosic molded body, a solution of Formed cellulose in a tertiary amine oxide in a warm state and the shaped solution introduced into a precipitation bath to precipitate the cellulose contained, wherein the warm, shaped solution is cooled prior to introduction into the precipitation bath. The cooling is carried out immediately after molding and is preferably in a horizontal blowing of the cellulosic molding with air.

In order to meet the requirements of the uniformity of the properties of the individual filaments and the demands for higher production speeds, the filaments must be cooled as uniformly and intensively after the extrusion. In the known device for this purpose a transverse flow blowing is used, which is formed on both longitudinal sides of the spinneret device and directly blows a flow of cooling air across the filament curtain on the filaments. The direct coincidence of the cooling air streams outside the filament curtain leads to air turbulences, which act in particular on the filaments which are guided directly in the edge zones of the filament curtain.

To prevent such disturbing effects, although from the DE 33 18 096 a device is known in which adjustable guide plates are arranged parallel to the end faces of the filament curtain. However, only certain flow guides of the cooling air with respect to the environment can be achieved with this. The cooling of the filaments in the edge zones as well as the edge flow effects can hardly be influenced hereby.

It is therefore an object of the invention to provide a method and a device of the type mentioned, in which or in which all filaments of a filament curtain, in particular in the edge zones of the filament curtain are intensive and uniformly coolable.

This object is achieved by a method with the features of claim 1 and by an apparatus for performing the method with the features of claim 9.

Advantageous developments of the invention are defined by the features and feature combinations of the respective subclaims.

The invention is characterized in that the guided in a lateral edge zone of the filament curtain filaments are guided in a predetermined atmosphere with defined flow conditions. For this purpose, at least on one end face of the spinneret device, an additional blowing stream is generated by a blowing agent, which acts directly on the filaments guided in the edge zone of the filament curtain. Air turbulence by a transverse cooling air flow at the edge of the filament curtain can thus be advantageously avoided. In particular, equalization of the blowing conditions by the cooling air flow could be achieved by the blowing flow.

In order to obtain the same effects at each edge zone of the filament curtain, a separate blowing stream directed transversely to the cooling air flow is preferably applied to the filaments at each edge zone of the filament curtain. For this purpose, separate blowing means are provided on both end faces of the spinneret device.

In order to effect the cooling of the filaments of the filament curtain substantially by the transverse cooling air flow, the development of the inventive method is particularly advantageous, in which the blowing flow is generated adjacent to the edge zone of the filament curtain with a blowing direction in the direction of the filaments, wherein between the filaments and the blowing flow is adjusted to a blowing angle in the range of 0 ° to 45 °. So lets in extreme cases, a parallel flow to the filament curtain, which essentially only affects the edge air layers of the filament curtain. In order to be able to use additional cooling effects of the blowing flow, the blowing angle is advantageously increased, wherein blowing angles in the range of up to 45 ° have been found suitable in order to avoid undue deviations in the cooling conditions between the center of the filament curtain and the edge zones of the filament curtain.

Preferably, the blowing streams in both edge zones of the filament curtain will impact the filaments with an angle of incidence in the range of 0 ° to 20 °. For this purpose, the device according to the invention has in each case a blow opening and a pressure chamber connected to the blow opening, wherein the blow opening has a tendency to form an angle of attack between the filaments and the blow stream in the range of 0 ° to 45 °.

The method variant, in which the blowing stream and the filaments meet in an entry region of the cooling zone, enables a uniform spinning out of all the filaments. Only after passing through a short spinning zone are the filaments confronted with the blowing stream.

In order to obtain an effect of the blowing flow in the edge zones of the filament curtain which is as good as possible over the entire cooling length section, the blowing flow is generated according to an advantageous variant of the method with a blowing speed which is greater than the blowing speed of the cooling air flow. This allows a turbulence-free flow in the edge region of the filament curtain to be produced up to the outlet side of the cooling device.

The blow stream and the cooling air flow are preferably formed by a climatic air, which has a substantially equal temperature. In principle, however, it is also possible to supply the blowing flow and the cooling air flow with different temperatures to the filament curtain. Thus, the blowing flow can also be advantageously formed by a room air.

In order to obtain a sufficient cooling of the filaments even at a high filament density within the filament curtain, a second cooling air flow is preferably act on the filaments within the cooling zone, which is blown transversely to the filament curtain against the first cooling air flow. Thus, the filament curtain can be cooled intensively and evenly on both sides.

In the apparatus according to the invention, the blowing agent is preferably formed by a blowing opening directed onto the edge zone of the filament curtain and a pressure chamber connected to the blowing opening. In this case, the blowing opening preferably has a rectangular outlet cross-section, which extends aligned substantially parallel to the end face of the spinneret device over the entire thickness of the filament curtain.

In order to obtain a turbulence-free flow as far as possible within the blowing flow, a flow rectifier is arranged within the blowing opening.

The device according to the invention is operated according to a preferred development with a cooling device which contains a blow-by with a blow chamber on both longitudinal sides of the spinneret device. Thus, two separate cooling air streams can be generated, which are each directed transversely to the filament curtain on the filaments. Such cooling devices allow intensive cooling, which even at high filament densities within the filament curtain high process speeds are possible.

In order to influence the flow forming parallel to the edge zones of the filaments, it is further proposed that the blowing means are each assigned one or more cover plates which extend at a distance parallel to the edge zones of the filaments and are designed to be displaceable. Thus, additional flow effects can be generated to equalize an edge flow. Thus, with partial coverage, the sucked in ambient air can be used.

The inventive method is described in more detail below with reference to some embodiments of the device according to the invention for carrying out the method with reference to the accompanying figures.

Fig. 1

schematisch eine Ansicht eines ersten Ausführungsbeispiels der erfindungsgemäßen Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens.

Fig. 2

schematisch eine Querschnittsansicht des Ausführungsbeispiels aus Fig. 1

Fig. 3

schematisch eine Draufsicht eines weiteren Ausführungsbeispiels der erfindungsgemäßen Vorrichtung

Fig. 4

eine Querschnittsansicht eines weiteren Ausführungsbeispiels der erfindungsgemäßen Vorrichtung.

They show:

Fig. 1

schematically a view of a first embodiment of the device according to the invention for carrying out the method according to the invention.

Fig. 2

schematically a cross-sectional view of the embodiment of Fig. 1

Fig. 3

schematically a plan view of another embodiment of the device according to the invention

Fig. 4

a cross-sectional view of another embodiment of the device according to the invention.

In Fig. 1 and Fig. 2 a first embodiment of the device according to the invention for carrying out the method according to the invention for melt-spinning and cooling a plurality of filaments is shown. In Fig. 1 the embodiment is schematically in a view and in Fig. 2 shown schematically in a cross section. Inasmuch as no reference is made to one of the figures, the following description applies to both figures.

The exemplary embodiment has a spinneret device 1, which preferably has a multiplicity of nozzle bores on its underside in a row-shaped arrangement. The spinneret device 1 is connected via a melt inlet 2 with a melt source (not shown here).

Below the spinneret 1 a cooling device 3 is arranged. Between the spinneret device 1 and the cooling device 3, a short spinning zone is formed, in which the filaments are guided without active cooling. The cooling device 3 has a blowing wall 4.1 extending parallel to a longitudinal side of the spinneret device 1, which is connected to a blast chamber 5.1. The blow chamber 5.1 is connected via an air feed 17 with a cooling air source (not shown here). As a cooling air source in this case a fan or an air conditioning device may be provided.

At both end faces of the spinneret device 1, the cooling device 3 each have a separate blowing agent 8.1 and 8.2. In Fig. 2 the blowing means 8.1 and 8.2 are each shown in a cross-sectional view, wherein the blowing agent 8.1 the left end of the spinneret 1 and the blowing means 8.2 the right end of the spinneret 1 is assigned. The blowing agent is 8.1 by a blow opening 9.1 and connected to the blow opening 9.1 pressure chamber 10.1. educated. The pressure chamber 10.1 is connected to a pressure source, not shown here. The blowing means 8.2 arranged on the opposite end side are likewise formed into a blowing opening 9.2 and a pressure chamber 10.2 connected to the blowing opening 9.2. The pressure chamber 10.2 is also connected to a pressure source. The blowing openings 9.1 and 9.2 have a substantially rectangular outlet cross-section, in each of which a flow rectifier 11 is arranged. The blow opening 9.1 on the left end side of the spinneret device has an inclination relative to a vertical, so that the blow stream exiting from the outlet cross section of the blow opening 9.1 strikes the extruded filaments 6 through the spinneret device 1 with an angle of attack. In Fig. 2 the blowing angle is indicated by the reference character α.

The blast opening 9.2 on the opposite end face of the spinneret device 1 is formed substantially mirror-inverted to the blow opening 9.1. In this case, the blow opening 9.2 has an opposite inclination, so that the blow stream exiting from the outlet cross section of the blow opening 9.2 strikes the extruded filaments 6 through the spinneret device 1 with an angle of attack. The blowing angle is also characterized by the reference character α. The Anblaswinkel and thus the arrangement of the blowing openings 9.1 and 9.2 are preferably the same on both sides of the spinneret device 1.

How out FIG. 1 shows, below the cooling device 3, a discharge nozzle 12 is arranged to deduct the filaments 6 of the spinneret device 1 and place on a arranged below the discharge nozzle 12 storage belt 13 as a spunbonded fabric 18. The storage belt 13 is designed to be permeable to air and is driven transversely to the draw-off nozzle 12 via a drive system, which is not described here in more detail.

At the in Fig. 1 and 2 apparatus according to the invention shown the spinneret 1 is fed to a polymer melt and extruded under pressure from the arranged on the underside of the spinneret 1 nozzle bores. The emerging from the nozzle bores of the spinneret 1 filaments 6 are guided in a row-like arrangement as a so-called filament curtain 7. The filament curtain 7 is drawn off from the spinneret device 1 through the draw-off nozzle 12. For this purpose, the filament curtain 7 is guided through a guide channel 14 of the discharge nozzle 12, in which a delivery fluid is introduced.

Before the filaments 6 of the filament curtain 7 enter the guide channel 14 of the draw-off nozzle 12, cooling takes place by a cooling air flow directed transversely to the filament curtain 7 in the cooling zone formed by the cooling device 3. For this purpose, the cooling air flow is generated by the blowing chamber 5.1 and the blowing wall 4.1 and is blown uniformly over the entire width and length of the blowing wall 4.1 onto the filaments 6 of the filament curtain 7. In order to avoid air turbulence at the edge zones of the filament curtain 7 formed by the end faces of the spinneret device 1, an additional blowing stream is produced by the blowing agents 8.1 and 8.2 which strikes the filaments 6 guided in the edge zones of the filament curtain 6 with an angle of incidence α of approximately 20 ° , The blowing stream generated by the blowing agents 8.1 and 8.2 is blown in the running direction of the filaments 6, so that no significant air friction phenomena the filaments occur. The transverse cooling air flow as well as the blowing flow set at the edge zones of the filament curtain 7 are matched to one another in such a way that a substantially uniform cooling of the filament strands within the filament curtain 7 occurs, at which point the filaments 6 are guided. The blowing stream is adjusted with respect to the transverse cooling air flow with a slightly higher blowing speed, so that the formation of air vortices is avoided over the entire cooling section and a uniform guidance of the filaments is ensured up to the discharge nozzle 12. The filament curtain 7 is picked up by the draw-off nozzle 12 and deposited as a spun-bonded non-woven 18 on the storage belt 13.

In order not to influence the spinning out of the filaments in the spinning zone, the blowing stream and the filaments meet in the inlet region of the cooling zone. Thus, the cooling air flow is superimposed over the entire length of the cooling zone with the blowing flow.

At the in FIGS. 1 and 2 illustrated embodiment, the blowing openings 9.1 and 9.2 are aligned such that the blower stream strikes the filaments 6 of the filament curtain 7 with an angle of about 20 °. In principle, blowing angles can be set which could be in the range of 0 ° to 45 ° in order to obtain advantageous guidance and cooling of the filaments in the edge zones of the filament curtain 7. Preferably, however, the blowing angle is set equal on both sides in a range of 0 ° to 20 °. In this case, the blowing openings 9.1 and 9.2 could each be formed on movable blast nozzles, by means of which an adjustment of the angle of attack is possible. In addition, it is also possible to generate the blast streams without the aid of flow rectifiers in the blow openings 91 and 9.2.

In Fig. 3 a further embodiment of the device according to the invention for carrying out the method according to the invention is shown. The embodiment according to Fig. 3 is formed substantially identical to the preceding embodiment, so that at this point schematically a plan view of the Ausführungsgbeispiels is shown. Below, essentially only the differences are explained.

At the in Fig. 3 illustrated embodiment, the cooling device 3 on both longitudinal sides of the spinneret 1 each have a blowing wall 4.1 and 4.2, which are each connected to a blast chamber 5.1 and 5.2. The blower walls 4.1 and 4.2 are arranged substantially parallel to the above the cooling device 3 arranged spinneret 1. The blow chambers 5.1 and 5.2 are connected to a cooling air source, not shown, so that the blow chambers 5.1 and 5.2 preferably filled with a cooling medium, a cooling air and is guided under pressure through the blowing walls 4.1 and 4.2 transverse to the filament curtain. To both end faces of the filament curtain, the blowing means are arranged 8.1 and 8.2. Each of the blowing means 8.1 and 8.2 has a blowing opening 9.1 and 9.2, through which a Blasluftstrom is generated and - as already described - blown with a Anblaswinkel on the filaments 6 of the filament curtain. Each blow opening 9.1 and 9.2 may include a flow straightener, by which a substantially rectified air flow is generated, so that over the entire thickness of the filament curtain 7 uniform blow stream. Each of the blowing openings 9.1 and 9.2 is connected to a pressure chamber 10.1 and 10.2.

At the in Fig. 3 In the embodiment shown, particularly high filament densities within the filament curtain 7 can be intensively and uniformly cooled. Due to the intensive cooling effect, it is advantageously possible to set high take-off speeds by means of a downstream draw-off nozzle.

In Fig. 4 a further embodiment of the device according to the invention for carrying out the method according to the invention is shown schematically in a longitudinal sectional view. The embodiment is essentially identical to the embodiment according to Fig. 3 so that only the differences are explained below.

The cooling device 3 arranged below the spinneret device 1 is formed by the blowing walls 4.1 and 4.2 with the blow chambers 5.1 and 5.2 extending on the longitudinal sides. For each end face a blowing agent is provided 8.1 and 8.2, wherein in the illustration in Fig. 4 only the blowing agent 8.2 is shown. At the end faces of the filament curtain 7 a plurality of cover plates are provided in order to make a shielding of the filaments 6 with respect to the environment can. In Fig. 4 are the the blowing agent 8.2 associated cover plates 19.1 and 19.2 shown. The cover plates 19.1 and 19.2 are slidably held in an upper guide 20 and a lower guide 21. In this case, the cover plates 19.1 and 19.2 can be adjusted as desired between a closed position and an open position. In the open position, a lateral air outlet 22 is formed. This allows additional flow effects to be generated at the edge zones of the filament curtain 7 within the cooling zone.

The filament curtain 7 is drawn off from the spinneret device 1 through the draw-off nozzle 12. The guided in the guide channel 14 filament curtain 7 is thereby promoted by a conveying fluid that is supplied to the guide channel 14 via the fluid chambers 16.1 and 16.2 and the fluid inlets 15.1 and 15.2.

The in the Fig. 1 to 4 illustrated embodiments of the device according to the invention for carrying out the method according to the invention are exemplary in construction and arrangement of the blowing agent. It is essential that a additional blowing stream for guiding the filaments at the edge zones of the filament curtain can be generated. In particular, the air turbulence generated by a transverse flow blowing at the edge zones of the filament curtain should be avoided.

LIST OF REFERENCE NUMBERS

1

Spinning nozzle device

2

melt inlet

3

cooling device

4.1, 4.2

blowing wall

5.1,5,2

puffer

6

filaments

7

filament curtain

8.1, 8.2

blowing agent

9.1,9.2

blowing opening

10.1, 10.2

pressure chamber

11

Flow straightener

12

navel

13

depositing belt

14

guide channel

15.1, 15.2

fluid inlets

16.1, 16.2

fluid chambers

17

air supply

18

spunbond

19.1, 19.2

cover

20

upper guide

21

bottom guide

Claims (18)

1. Method for melt spinning and cooling a plurality of filaments, in which the filaments are guided after extrusion arranged in a row as a filament curtain through a cooling zone and are cooled by a cooling air stream blown transversely to the filament curtain,
   characterized in that
   an additional quenching stream acts inside the cooling zone on the filaments guided in a lateral edge zone of the filament curtain.
2. Method according to claim 1,
   characterized in that
   a separate quenching stream oriented transversely to the cooling air steam acts on the filaments on each edge zone of the filament curtain.
3. Method according to method 1 or 2,
   characterized in that
   the quenching stream is created next to the edge zone of the filament curtain in a quench direction oriented towards the running direction of the filaments, wherein a quench angle in the range of 0° to 45° is configured between the filaments and the quenching stream.
4. Method according to claim 3,
   characterized in that
   each of the quenching streams in both the edge zones of the filament curtain impinge on the filaments preferably at a quenching angle in the range of 0° to 20°.
5. Method according to any of the claims 1 to 4,
   characterized in that
   the quenching stream and the filaments concur in an inlet region of the cooling zone.
6. Method according to any of the preceding claims
   characterized in that
   the quenching stream is created whose quenching speed is greater than the quenching speed of the cooling air stream.
7. Method according to any of the claims 1 to 6
   characterized in that
   the quenching stream and the cooling air stream are each formed by conditioned air, which essentially has the same tempering.
8. Method according to any of the claims 1 to 7
   characterized in that
   a second cooling air stream, which is blown transversely to the filament process opposite to the first cooling air stream, acts on the filaments inside the cooling zone.
9. Device for carrying out the method according to any of the claims 1 to 8, said device comprising an oblong spinneret (1) with nozzle bores arranged in a row for extruding a plurality of filaments (6) and a cooling unit (3) arranged below the spinneret (1), wherein the cooling unit (3) comprises at least one quenching wall (4.1) oriented parallel to a longitudinal side of the spinneret (1) and a quenching chamber (5.1) which is connected to the quenching wall (4.1) and through which a cooling air stream oriented transversely to the filaments (6) guided as a filament curtain (7) can be created,
   characterized in that
   a quenching means (8.1) is assigned to at least one front side of the spinneret (1), wherein an additional quenching stream is blown by said quenching means (8.1) on the filaments (6) guided in a lateral edge zone of the filament curtain.
10. Device according to claim 9
    characterized in that
    on both the front sides of the spinneret (1), separate quenching means (8.1, 8.2) are arranged, using each of which a quenching stream oriented transversely to the cooling air stream can be created.
11. Device according to claim 9 and 10,
    characterized in that
    the quenching means (8.1) is formed by a quench opening (9.1) oriented towards the edge zone of the filament curtain and a pressure chamber (10.1) connected to the quench opening (9.1) and that the quench opening (9.1) has an inclination for forming a quenching angle (α) in the range of 0° to 45° between the filaments (6) and the quenching stream.
12. Device according to claim 11,
    characterized in that
    on both the front sides of the spinneret (1) one quench opening (9.1, 9.2) each is provided, said quench opening having an inclination for forming a quenching angle (α) in the range of 0° to 20° between the filaments (6) and the quenching stream.
13. Device according to claim 11 or 12
    characterized in that
    the quench opening (8.1, 8.2) has a rectangular outlet cross-section, which extends essentially parallel to the front side of the spinneret (1) over the thickness of the filament curtain (7).
14. Device according to any of the claims 11 to 13
    characterized in that
    a flow straightener (11) is arranged inside the quench opening (9.1, 9.2).
15. Device according to any of the claims 9 to 14
    characterized in that
    the quenching means ([8].1, 8.2) is arranged in the inlet region of the cooling device (3).
16. Device according to any of the claims 9 to 15
    characterized in that
    the quenching means (8.1, 8.2) and the quenching chamber (5.1) are connected to a common cooling air source.
17. Device according to any of the claims 9 to 16
    characterized in that
    the cooling unit (3) comprises on the opposite longitudinal side of the spinneret (1) a second quenching chamber (5.2) having a quenching wall (4.2), wherein said quenching chamber (5.2) blows a second cooling air stream transversely to the filament curtain opposite to the first cooling air stream.
18. Device according to any of the claims 9 to 17
    characterized in that
    one or more cover plates (19.1, 19.2) are assigned to each of the quenching means (8.1, 8.2), wherein said cover plates extend at a distance from and parallel to the edge zones of the filaments (6) and are embodied to be displaceable.

Images