WO2017025372A1

WO2017025372A1 - Method and device for melt-spinning a synthetic thread

Info

Publication number: WO2017025372A1
Application number: PCT/EP2016/068306
Authority: WO
Inventors: Dieter Wiemer; Jörg SCHIPPEL
Original assignee: Oerlikon Textile Gmbh & Co. Kg
Priority date: 2015-08-08
Filing date: 2016-08-01
Publication date: 2017-02-16
Also published as: JP2021105241A; JP7053922B2; CN107923072A; CN107923072B; DE112016003628A5; JP2018523029A

Abstract

The invention relates to a method and a device for melt-spinning a synthetic thread consisting of a number of 50 to 400 microfilaments with a filament titer ranging from 0.1 to 0.7 den. The microfilaments are extruded through nozzle bores of a round spinneret and subsequently guided through a first solidification zone without active cooling and a second solidification zone with active cooling. After the cooling process, the microfilaments are combined into a thread at a convergence point. The aim of the invention is to achieve a spinning draft/cooling process interaction which is advantageous for the design of properties and filament cross-sections. According to the invention, this is achieved in that the microfilaments are pushed out of a respective opening cross-section of the nozzle bores with a diameter ranging from 0.12 mm to 0.50 mm during the extrusion process. Subsequently, the microfilaments are guided over a minimum length of 50 mm without active cooling in the first solidification zone and are actively cooled in the second solidification zone by a cooling air which flows radially from the outside towards the inside. In the process, the microfilaments are drawn-off with a draw-off speed ranging from 1400 m/min to 3000 m/min after being combined into the thread.

Description

Method and apparatus for melt spinning a synthetic

thread

The invention relates to a method for melt-spinning a synthetic thread according to the preamble of claim 1 and to an apparatus for carrying out the method according to the preamble of claim 9.

In the production of synthetic threads, it is common that first in a melt spinning process, a plurality of fine filaments are extruded by means of a spinneret. Thus, a melt of a polymer is forced through a plurality of fine nozzle bores of the spinnerets under high pressure, so that one filament is formed per nozzle bore. After cooling and solidification of the filaments, these are brought together and form a multifilament thread. In particular, for use in textile materials, there is now an increasing desire to form the filament of the finest filaments called microfilaments. This makes it possible to produce very soft, flexible, lightweight and resistant textile materials. However, to meet the requirements for the textile applications, the microfilaments of the thread must be produced with high uniformity in their physical properties and in their length properties. Due to the fineness, in particular the solidification of the microfilaments immediately after extrusion is known to be particularly sensitive. For example, an attempt was made to perform the solidification of the microfilaments forced by a cooling air as gently as possible. DE 198 21 778 A1 discloses a method and an apparatus for the production of microfilaments with high titer uniformity, in which the microfilaments after extrusion pass through a first solidification zone without active cooling and a second solidification zone with active cooling. In the second solidification zone with active cooling, a cooling air flow is generated by a blow candle arranged in the interior of the filament bundle and is blown radially from the inside to the outside. The filament curtain formed around the blow candle is widened. However, these expansions act directly on the first solidification zone, in which the microfilaments are still more or less molten. In that regard, unevenness in the formation of the filament cross section can not be avoided.

In addition, it is necessary to divide the filament curtain at the periphery of the blow candle in one place to allow the cooling air supply to the blow candle. As a result, a portion of the filaments in the area between the spinneret and a convergence point is deflected more. However, these differences directly affect the so-called spinning delay, which is decisive for the molecular orientation and the cross-sectional formation of the microfilament. Such irregularities in the formation of the microfilaments, however, become noticeable negatively by what are known as color spots or stripes, especially in the case of dyeings in the textile fabric.

It is an object of the invention to provide a method and an apparatus for melt-spinning a synthetic thread of the generic type in such a way that a substantially uniform spinning delay and cooling acts on each of the microfilaments.

Another object of the invention is to provide a generic method and a generic device for melt spinning a synthetic thread with which in particular synthetic filaments of microfilaments with a Filamenttiter in the range of 0, 1 to 0.7 to produce for textile applications are.

This object is achieved by a method with the features of claim 1 and by a device having the features of claim 9.

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

The invention takes into account the interaction of spinning distortion and cooling to form uniform filament cross-sections after extrusion. Thus, it is well known that an increasing drawdown speed with larger nozzle bores leads to an increase in the preorientation of the molecules. On the other hand, it is also known that delayed cooling below the spinneret prevents rapid filament surface cooling and preorientation caused thereby. In that regard, it is particularly necessary in training fine microfilament cross sections to bring the cooling and the spinning delay in line. The inventive method therefore provides that the microfilaments during extrusion from each an opening cross-section of the nozzle holes in the range of 0.12 mm to 0.50 mm emerge and are performed in the first solidification zone over a minimum length of 50 mm without active cooling. Thereafter, in the second solidification zone, cooling of the microfilaments takes place by means of a cooling air flowing radially inwards, the microfilaments being taken off after being brought into the yarn at a take-off speed in the range of 1400 m / min to 3000 m / min. The withdrawal speed depends essentially on the type of thread, for example, whether an undrawn thread (POY) or a fully drawn thread (FDY) is to be produced. Due to the cooling air directed from the outside to the inside of the filaments, neither a widening nor a deflection of the microfilaments is produced. Thus, very stable uniformly acting on all filaments solidification of microfilaments can arise. Due to the relatively elongated first solidification zone, a sufficient jacket strength of the microfilaments is achieved, so that a stable inlet into the solidification zone with cooling is possible.

In order not to obtain too high exit velocities when extruding the microfilaments, it is further provided that the microfilaments are extruded through the nozzle bores with an overpressure of a melt in the range of 50 bar to 150 bar, the opening cross sections of the nozzle bores each extending over a length in the Range from 0.4 mm to 1.5 mm. In this case, a ratio between the length of the nozzle bores and the opening cross section of the nozzle bores of approximately 3 is preferably desired. The very stable titer uniformity of all microfilaments within the thread has a particularly high effect on uniformity of dyeing. Therefore, the process variant according to the invention is preferably carried out, in which the melt is dyed directly before extrusion with a dye or a colored masterbatch. Thus, a subsequent coloring of the microfilaments is no longer necessary.

Due to the all-round radially entering cooling air within the second solidification zone, the active cooling can be realized in a relatively short cooling section of the solidification zone. For this purpose, the microfilaments are guided over a length in the range of 150 mm to 250 mm with active cooling through the second solidification zone. The set cooling air consumption depends on the number of gelichzeitig extruded microfilaments, with very fine and few microfilaments with a cooling air flow of about 35 Nm ³ / h and a large number of microfilaments with a cooling air flow of about 120 Nm ³ / h are cooled ,

The cooling air is thereby guided particularly gently on the microfilaments, for this purpose the cooling air flow is generated according to an advantageous development of the method for active cooling of the microfilaments by a gas-permeable cylinder jacket of a microfilaments surrounding the screen cylinder, which is arranged within a filled with cooling air pressure chamber.

The cooling air is passed through a gas-permeable bottom of the pressure chamber into the interior of the pressure chamber. So arise over the entire circumference of the screen cylinder gelichmäßige pressure conditions that blow the cooling air flow to the microfilaments.

Depending on the number of microfilaments extruded through the spinneret and the resulting filament density, the merging of the microfilaments into the thread can be carried out at different distances from the spinneret. Thus, the microfilaments are preferably combined with a distance of 400 mm to 1500 mm below the spinneret to the thread.

The method according to the invention is thus particularly suitable for producing, for example, a synthetic thread made of a polyester or a polyamide with microfilaments.

For carrying out the method according to the invention, in particular the device according to the invention is suitable, in which the nozzle bores have an identical opening cross section in the range of 0.12 mm to 0.50 mm, in which the first solidification zone has a minimum length of 50 mm and in which the cooling air blowing means is cylindrical, that a cooling air acts radially from outside to inside on the microfilaments. This also makes it possible to produce a relatively high number of microfilaments with essentially identical filament cross-sections and identical physical properties with the same spin-off.

The nozzle bores preferably have an identical length in the range of 0.4 mm to 1.5 mm. This can be used to train the extant filament cross sections required and desired longitudinal diameter ratios of the nozzle bores are maintained.

In order to obtain a separation between passive and active cooling, the development of the device according to the invention is particularly advantageous, in which the second solidification zone extends within a gas-permeable cylinder jacket of the cooling-blowing agent, which has a cooling length in the range of 150 mm to 250 mm for guiding the microfilaments , This achieves the necessary cooling effects on the microfilaments for solidification and solidification. The supply of the cooling air for cooling the microfilaments is preferably realized in that the cooling-blowing means has a pressure chamber in which a screen cylinder is arranged with the gas-permeable cylinder wall. Thus, a uniform cooling air flow over the length and over the cross section of the screen cylinder can be achieved.

The supply of cooling air is preferably carried out via an open surface of the cylinder jacket of the screen cylinder, which is evenly distributed over the cylinder jacket and has a size in the range of 5% to a maximum of 12% of a total surface of the cylinder jacket. Thus, the cooling air quantities can be kept correspondingly low and act evenly on the microfilaments.

It has been found that the supply of cooling air via an air distribution chamber leads to a particularly uniform flow. The Air distribution chamber is arranged coaxially to the pressure chamber and connected via a gas-permeable bottom to the pressure chamber. So a multiple deflection of the cooling air flow is required to enter the inside of the screen cylinder. This avoids any turbulence in the supply of cooling air.

In order to obtain a calmed as possible first solidification zone, the development of the device according to the invention is particularly preferred in which the first solidification zone is formed within the cooling device by a partially conical shell ring, which faces with a free end of the spinneret and a shell end of the cylinder jacket covering on the screen cylinder. The shape of the shroud allows a smooth transition between the first solidification zone and the second solidification zone. In addition, it is avoided by the cover of Siebzylindermantels in the upper region of the screen cylinder that volatile components from the first solidification zone deposited on the cylinder jacket. Thus, in particular in the case of a colored melt, colorless color particles occurring during extrusion can be bound from the first solidification zone.

The inventive device for carrying out the method according to the invention is characterized in particular by the gentle cooling in the second solidification zone.

The inventive method will be described below with reference to an embodiment of the device according to the invention with reference to the accompanying figures. They show:

Fig.l schematically shows a longitudinal sectional view of a first exemplary embodiment of the inventive apparatus for melt spinning a synthetic thread Figure 2 shows a schematic longitudinal sectional view of the cooling device

Fig.l

3 schematically shows a cross-sectional view of the cooling device of FIG.

2

4 shows schematically a detail of a longitudinal sectional view

Nozzle plate of the embodiment of Figure 1

5 shows schematically a longitudinal sectional view of a further exemplary embodiment of the device according to the invention for melt-spinning a plurality of synthetic threads.

In the Fig.l a first embodiment of the inventive apparatus for melt spinning a synthetic thread is shown schematically in a longitudinal sectional view. The embodiment comprises a spinning device 1 and a cooling device 8, which are arranged vertically with each other. The spinning device 1 consists in this embodiment of a heated spinning beam 2, which carries a Rundsp 3 on its underside innerspace. The rotary nozzle 3 is provided with a spinning pump 4 arranged on the upper side of the spinning beam 2 connected. The spinning pump 4 is connected via a melt inlet 5 with a melt generator, not shown here, for example an extruder or a polycondensation system. The spinning pump 4 is driven by a pump drive 29 at an operating speed and supplies a polymer melt under pressure to the round spinning nozzle 3. The device is shown for this purpose in Figure 1 in an operating condition.

The held within the spinning beam 2 round spinning nozzle 3 has at the bottom of a nozzle plate 6, which contains a plurality of nozzle bores. For explanation of the nozzle plate 6, reference is made in addition to FIG. 4 shows a section of the nozzle plate 6 of the round spinning nozzle 3 is shown. At the bottom, a plurality of nozzle bores 7 are formed in the nozzle plate 6, which opens directly into a respective melt channel 34 within the nozzle plate 6. The nozzle bores 7 have a free flow cross-section 38, which is characterized by a diameter with the letter d. The free flow cross-section 38 in the nozzle bores 7, for carrying out the method according to the invention, has a diameter d as a function of the respective microfilament to be produced of a minimum of 0.12 mm to a maximum of 0.50 mm. The opening cross section 38 extends within the nozzle plate 6 over a length which is indicated in Figure 4 by the letter L. To maintain a ratio between the length L of the nozzle bore 7 and the opening cross section 38 of the nozzle bore 7 of 2.5 to 3.5, the length L of the nozzle holes 7 in dependence on the diameter d of the opening cross-section 38th limited. For the inventive method, the length L of the nozzle bore 7 is limited to a range of 0.4 mm to 1, 5 mm. Thus, over the diameter d and the length L of the nozzle bore 7, the exit velocity of the melt during extrusion of the microfilaments can be fixed in an area adapted to the take-off speed and thus to the desired spinning delay. Here, the pending within the spinneret melt pressure is used as a control variable to change the flow.

The nozzle plate 6 held on the underside of the round spinning nozzle 3 has a number of at least 50 to a maximum of 400 nozzle bores 7, depending on the desired number of microfilaments. The nozzle bores 7 are preferably uniformly distributed over a circular area of the nozzle plate 6. With a smaller number of nozzle bores 7, however, it is also possible to make the distribution of the nozzle bores 7 on the nozzle plate 6 annular.

As can be seen from the illustration in FIG. 1, a cooling device 8 immediately follows below the spinning beam 1. The cooling device 8 is held in a sealing manner on the underside of the spinning bar 2, with a first solidification zone 9 and a second solidification zone 10 immediately following below the round spinning nozzle 3. The first solidification zone 9 is formed between the circular spinning nozzle 3 and a cooling air blowing means 1 1. Within the first solidification zone 9 no active cooling takes place. The cooling air blowing means 1 1 is associated with the second solidification zone 10 and is formed in this embodiment by a screen cylinder 12 with a gas-permeable cylinder wall 13. The screen cylinder 12 is open at its end faces, so that a filament bundle extruded through the circular spinning nozzle 3 can pass through the screen cylinder 12. The screen cylinder 12 is disposed within a pressure chamber 14 which is filled with a cooling air. The cooling air is supplied via a vertically arranged below the pressure chamber 14 air distribution chamber 15 through a gas-permeable bottom 17 of the pressure chamber 14. The air distribution chamber 15 is connected via an air connection channel 16 with a cooling air source, not shown here. Within the air distribution chamber 15, an outlet port 18 is disposed concentrically below the screen cylinder 12 and forms a yarn outlet 25th

For further explanation of the function of the cooling device 8 is taken in addition to the figures 2 and 3 reference. FIG. 2 shows a longitudinal sectional view of the cooling device, and FIG. 3 shows a cross-sectional view of the cooling device. Unless an explicit reference is made to one of the figures, the following description applies to all figures. In order to keep the temperature of the round spinning nozzle 3 within the spinning beam 2 uninfluenced by the formation of the first solidification zone 9 as far as possible, an insulating plate 19 is arranged concentrically with the circular spinning nozzle 3 on the underside of the spinning beam 2. In that regard, the round spinning nozzle 3 is held offset to an underside of the spinning beam 2. On the insulating plate 19, a pressure plate 20 connects, the Usually is firmly connected to the spinning beam 2. The pressure plate 20 cooperates with a seal 21, which is held on an upper side of the pressure chamber 14. The pressure chamber 14 is designed box-shaped for this purpose. Within the pressure chamber 14 of the screen cylinder 12 is arranged, which completely penetrates the pressure chamber 14 and thus forms at the top of the pressure chamber 14 and at the bottom of the pressure chamber 14 each have an opening for guiding the microfilaments. At the upper end of the screen cylinder 12, a shroud 22 is held. The shroud 22 protrudes with a free end 23 to the nozzle plate 6 of the round spinning nozzle 3 with an opposite cover end 24 of the shroud 22 protrudes into the interior of the screen cylinder 12 and forms a cover. The shroud 22 is conical, so that a smooth transition between the larger diameter round spinning nozzle 3 and the screen cylinder 12 is established. The shroud 22 thus forms the lower end of the first solidification zone 9, in which the microfilaments are passed directly after the extrusion through the nozzle plate 6 without cooling. The first solidification zone 9 has a length, which is marked in Fig.l and Fig.2 with the code letter Ej. Within the first solidification zone 9, in particular, the orientation of the molecular chains of the filament material is influenced up to a preconsolidation at the edge of the microfilaments. For the method according to the invention, a minimum length Ej of at least 50 mm must be observed. Within this minimum length, which can be extended to a length of Ej = 75 mm for larger filament titers of, for example, 0.5 mm, the microfilaments are guided through a calmed atmosphere. The change in the length of the first solidification zone Ej can be realized in a simple manner by replacing the shroud 22. In order to generate a cooling air flowing radially from outside to inside, the screen cylinder 12 is held within the pressure chamber 14. The screen cylinder 12 has a gas-permeable cylinder wall 13, which is preferably formed of several layers. An inner wall 39 facing the microfilaments is preferably designed as a perforated plate cylinder. To even out the cooling air flowing from the pressure chamber of the pressure chamber 14 through the cylinder wall 13, an outer wall 40 is designed, for example, as wire mesh. In this case, the inner wall 39 and the outer wall 40 of the cylinder wall 13 may be arranged at a distance from each other.

The amount of air which is blown over the screen cylinder 12 for cooling the microfilaments 12 is determined by the permeability of the cylinder wall 13 of the screen cylinder 12. For this purpose, the cylinder wall 13 has an open area, which is open over the cylinder jacket, in the range from 5% to a maximum of 12% of a total area of the cylinder jacket. The open area of the cylinder wall 13 can be determined, for example, by a perforation of the inner wall 39. The uniform distribution of the open area on the circumference of the screen cylinder 12 allows a radial supply of cooling air over the circumference of the screen cylinder 12 and the length of the screen cylinder 12 for cooling the microfilaments. The exit velocity of the cooling air is determined only by the pressure generated within the pressure chamber 14. This acts over the entire interior of the pressure chamber 14, so that a uniform influx arrives on all sides of the microfilaments. As can be seen from the illustration in FIG. 1 and FIG. 2, the screen cylinder 12 extends within the second solidification zone 10. The second solidification zone 10 thus represents the region in which the microfilaments are actively cooled. Due to the high uniformity of the blowing particularly uniform filament cross sections and thus a high titer uniformity are generated. The length of the second solidification zone 10 is identified by the reference E ₂ . The second solidification zone 10 has to carry out the method according to the invention a length Ej in the range of 150 mm to 250 mm. Here, the number of microfilaments and the filament titer is decisive for the length of the active cooling.

As can be seen from the illustration in FIG. 1, the microfilaments 30 are brought together to form a thread 31. For this purpose, a collecting yarn guide 26 is provided below the round spinning nozzle 3, which forms the so-called convergence point. In that regard, the collection thread guide 26 is held centrally to round spinning nozzle 3, so that the microfilaments 30 converge in the convergence point in the thread 31. The distance between the spinning nozzle underside of the round spinning nozzle 3 and the collecting thread guide 26 is marked with the identification letter k. Depending on the diameter of the Rundsp inndüse 3 and in dependence on the number of microfilaments, the distance k is a minimum of 400 mm and a maximum of 1500 mm. In particular, in this case a transition zone between the second solidification zone and the convergence point is used in order to obtain a homogenization of the cooling of the microfilaments. To homogenize the cooling while ambient air is used. Depending on the particular melt spinning process, the filaments can be wetted with a fluid simultaneously to aid cohesion. The fluid can be applied by a pin or roller on the microfilaments. Below the collecting yarn guide 26, a take-off godet 27 for receiving the yarn 31 is arranged. The take-off godet 27 is driven by a godet drive 28.1 at a predetermined peripheral speed to draw the microfilaments after extrusion and to obtain a spinning distortion intended for the formation of the microfilaments. For carrying out the method, the take-off speed at the take-off godet 27 is set in the range of 1400 m / min to 3000 m / min, depending on the thread type. The take-off speed influences the spinning delay and thus the forming molecular structure. For the production of fully drawn yarns (FDY) therefore relatively low take-off speeds and for the production of partially drawn yarns (POY) relatively high take-off speeds are set.

The illustrated in Fig. L embodiment of the device according to the invention know a Abzugsgalette 27 downstream godet 33, which is coupled to a separate second godet drive 28.2. In the event that the draw godet 33 are not followed by any further draw godets, for example, an unstretched yarn (POY) could be produced. In this case, a relatively high take-off speed of about 2500 m / min is set on the withdrawal godet 27. In the event that the Streckgalette 33 even more Follow godets for drawing the thread 31, the withdrawal speed for influencing the pre-orientation and the drawability, for example, at a peripheral speed of 1500 m / min would be set. The apparatus shown in FIG. 1 for carrying out the method according to the invention for melt-spinning a synthetic thread of a multiplicity of microfilaments is preferably used to extrude already-colored polymer melts, for example, of polyester or polyamide. The melt supplied via a melt source can be colored directly by supplying a dye, for example in the extruder or in a melt stream, or by combining a melt stream with a masterbatch. However, such colored polymer melts have the disadvantage that some color particles detach during extrusion and enter directly into the first solidification zone. By the shroud 22, however, it is achieved that these free color particles settle directly on the circumference of the shroud 22 and do not enter the second solidification zone. In that regard, the device according to the invention has proven particularly useful to extrude colored melts to microfilaments. When extruding the microfilaments, the melt is forced through the nozzle bores 7 of the nozzle plate 6 at a melt pressure within the spinneret in the range from 50 bar to 150 bar. This achieves a melt throughput adapted to the respective take-off speed and the desired filament titer of the microfilament. To maintain a filament titer in the range of 0.3 to 0.7 den Düsennplatten 6 used, the nozzle bores 7 have an identical opening cross section with a diameter in the range of 0.12 mm to 0.5 mm.

The microfilaments then pass through the first solidification zone, which has a minimum length of 50 mm. Here a preorientation and preconsolidation in particular of the marginal layers of the microfilaments takes place. By means of a spinning delay determined by the take-off speed and the flow speed, the desired preorientations and cross-sectional formations are achieved. To solidify the entire Filamentquerschnitts the microfilaments are passed through the second solidification zone, and cooled over a cooling length in the range of 150 mm to 250 mm with a radially blown from outside to inside cooling air. The open area in the cylinder wall 13 of the screen cylinder 12 and the internal pressure of the cooling air in the pressure chamber 14 are dimensioned such that the microfilaments within the second solidification zone with a cooling air amount in the range of 35 Nm ³ / h to 120 Nm ³ / h are cooled. Again, the number of microfilaments is decisive for the amount of cooling air. For example, a thread called 200f384 requires a maximum amount of cooling air to evenly cool all 384 filaments. The first number 200 in the thread designation defines a total denier of the thread with 200 denier.

After cooling, the microfilaments are brought together by the collecting thread guide 26 to the thread 31 and through the Take-off godet 27 recorded at a peripheral speed in the range of 1400 m / min to 2000 m / min.

The method according to the invention and the device according to the invention are therefore suitable for producing all threads customary for textile applications, such as, for example, a thread 30f72 or 60fl28 or 100fl92 or even a thread 200f384. The filament titer is in a range of 0.1 to 0.7, preferably in a range of 0.3 to 0.5 den. In this case, polymer melts of polyester or polyamide are preferably extruded. A thread (POY) made of polyester with 144 filaments and a total titer of 70 den and dyed gray with the method according to the invention and the device according to the invention showed a high uniformity in the titer with a Uster in the normal test of 0.7 U%. The quality number, which is calculated from the strength and the residual strain, was 29.0. In this case, a spinneret with nozzle bores was used, each with a diameter of 0.2 mm and a ratio L / D of 3.0 were carried out. The spinneret was coupled to a spin pump which fed the polymer melt under a spinning pressure of 60 bar to the spinneret. To cool the filaments, the first solidification zone with a length (Ej) of 60 mm and the second solidification zone with a length (E2) of 161 mm were set. At a distance of 670 mm below the spinneret, the filaments were brought together by means of a preparation fluid to the thread. The thread was partially drawn and wound up at a take-off speed of 2700 m / min. In practice, it is common that several threads are generated simultaneously within a spinning position. For this purpose, an exemplary embodiment of the device according to the invention is shown in Figure 5, with which the inventive method is executable. The embodiment of Figure 5 shows a spinning device 1 and a cooling device 8 which generates a yarn sheet of four threads. The number of threads is exemplary.

In this embodiment, four round spinning nozzles 3 are arranged side by side on a spinning beam 2. The round spinning nozzles 3 are coupled via a distributor system 35 with a multiple spinning pump 4. The spinning pump 4 is driven by the pump drive 29. Via a melt inlet 5, the spinning pump 4 is connected to an extruder, not shown here. The cooling device 8 forms per Rundsp inndüse 3 respectively below the spinneret 3, a first solidification zone 9 and a second solidification zone 10. The formation of the solidification zones 9 and 10 below the spinneret 2 are identical to the embodiment of Figure 1, so that at this point reference to Fig.1 is taken and no further explanation takes place.

The second solidification zones 10 are in this case formed by the screen cylinders 12, which are all arranged together in a pressure chamber 14. In that regard, the screen cylinder 12 are supplied together from a pressure chamber 14 with a cooling air. The pressure chamber 14 is assigned to the bottom 17 an air distribution chamber 15 which is coupled via an air connection channel 16 with a cooling air source, not shown here. The pressure chamber 14 and the air distribution chamber 15 are the same size executed, so that over the gas-permeable bottom 17, a continuous flow of cooling air is passed into the upper pressure chamber 14.

Below the cooling device 8 a plurality of collecting yarn guides 26 and a plurality of preparation pins 36 are arranged to merge the microfilaments 30 into a thread 31 in each case. About the preparation pins 36, the microfilaments are wetted.

For picking up by a withdrawal godet 27, the threads 31 are brought together via a yarn guide 37 in order to be guided in parallel with the smallest possible thread pitch on the circumference of the withdrawal godet 27. The withdrawal godet 27 is driven directly via the godet drive 28. As far as all threads 31 of the yarn sheet are performed together on the circumference of the Abzugsgalette 27.

The function for extruding, cooling and peeling off the microfilaments is identical to the exemplary embodiment according to FIG. 1, so that no further explanation is given at this point and reference is made to the aforementioned description. The method according to the invention and the device according to the invention are therefore particularly suitable for producing a multiplicity of threads at the same time from extruded microfilaments.

Claims

Patent claims

Process for melt spinning a synthetic thread consisting of a number of 50 to 400 microfilaments with a filament titer in the range from 0.1 to 0.7, in which the microfilaments are extruded through nozzle holes of a round spinning nozzle, in which the freshly extruded microfilaments have a first solidification zone without an active cooling and a second solidification zone with active cooling, in which the microfilaments are brought together at a convergence point to form a thread, characterized in that the microfilaments are extruded from an opening cross section of the nozzle bores with a diameter in the range of 0.12 mm to 0.50mm, that the microfilaments in the first solidification zone are guided over a minimum length of 50 mm without active cooling, that the microfilaments in the second solidification zone are actively cooled with cooling air flowing radially from the outside to the inside and that the microfilaments After merging to form the thread, the threads are drawn off at a take-off speed in the range of 1,400 m/min to 3,000 m/min.

Method according to claim 1, characterized in that the microfilaments are extruded through the nozzle bores with an excess pressure of a melt in the range of 50 bar to 150 bar, the opening cross sections of the nozzle bores each being over a length in the range of 0.4 mm to 1. Extend 5mm.

3. The method according to claim 2, characterized in that the melt is colored with a dye or a colored masterbatch before extrusion.

4. Method according to one of claims 1 to 3, characterized in that the microfilaments are guided through the second solidification zone over a length in the range of 150 mm to 250 mm with active cooling.

5. The method according to claim 4, characterized in that the microfilaments are cooled within the second solidification zone with a quantity of cooling air in the range from 35 Nm ³ /h to 120 Nm ³ /h.

6. The method according to claim 4 or 5, characterized in that the cooling air flow for actively cooling the microfilaments is generated by a gas-permeable cylinder jacket of a screen cylinder enclosing the microfilaments, which is arranged within a pressure chamber filled with cooling air.

7. The method according to claim 6, characterized in that the cooling air is guided into the interior of the pressure chamber via a gas-permeable floor of the pressure chamber.

8. The method according to any one of claims 1 to 7, characterized in that the microfilaments are combined into the thread at a distance in the range of 400 mm to 1,500 mm below the spinneret.

9. Device for carrying out the method according to one of claims 1 to 8, with a round spinning nozzle (3) on an underside of a heated spinning beam (2), which has a nozzle plate (6) with a

5 Number of 50 to 400 nozzle holes (7) for extruding microfilaments, with a cooling device (8) adjoining the underside of the spinning beam (2), which has a first solidification zone (9) and a second solidification zone below the round spinning nozzle (3). (10), whereby the second solidification zone (10)

10 is assigned a cooling air blowing means (1 1), with a collecting thread guide (26) arranged centrally below the round spinning nozzle (3) for bringing the microfilaments together into a thread and with at least one driven take-off godet (27), characterized in that the nozzle bores (7) an identical one

15 opening cross section (38) with a diameter (d) in the range of 0.12 mm to 0.50 mm, that the first solidification zone (9) has a minimum length (Ej) of 50 mm and that the cooling air blowing agent (1 1) is cylindrical is designed so that cooling air acts radially from the outside to the inside on the microfilaments.

20

10. Device according to claim 9, characterized in that the nozzle bores (7) have an identical length (L) in the range of 0.4 mm to 1.5 mm.

25 1 1. Device according to claim 9 or 10, characterized in that the second solidification zone (10) extends within a gas-permeable cylinder wall (13) of the cooling air blowing agent (1 1), which is used for Guide of the microfilaments has a cooling length (egg) in the range of 150 mm to 250 mm.

12. The device according to claim 1 1, characterized in that the 5 cooling air blowing means (1 1) has a pressure chamber (14) in which a screen cylinder (12) with the gas-permeable cylinder wall (13) is arranged.

13. The device according to claim 1 1 or 12, characterized in that 10 the cylinder wall (13) of the screen cylinder (12) over the

Cylinder jacket has a uniformly distributed open area in the range of 5% to a maximum of 12% of a total area of the cylinder jacket.

H. Device according to claim 12 or 13, characterized in that the cooling device (8) has an air distribution chamber (15) connected to a cooling air source, which is arranged coaxially to the pressure chamber (14) and via a gas-permeable floor (17) to the pressure chamber

(14) is connected.

20 15. Device according to one of claims 1 1 to 14, characterized in that the first solidification zone (9) within the cooling device (8) is formed by a partially conical jacket ring (22) which is connected to a free end of the round spinning nozzle ( 3) is facing and the one end of the jacket

25 cylinder jacket on the screen cylinder (12).

16. Device according to one of claims 9 to 15, characterized in that the collecting thread guide (26) is at a distance (k) is arranged in the range from 400 mm to 1500 mm below the nozzle plate (6) of the round spinning nozzle (3).