Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/08—Melt spinning methods
  • D01D5/088—Cooling filaments, threads or the like, leaving the spinnerettes

Definitions

• the invention relates to a method for cooling melt-spun filaments made of thread-forming polymers and to an apparatus for carrying out the method.
• Filament yarns and staple fibers made of thread-forming polymers such as polyester, polyamides or polyolefins are usually produced using the melt spinning process.
• a polymer melt is fed to a spinning pump which conveys the melt through the spinnerets in the so-called spinning beam.
• the melt emerging from the nozzles in the form of liquid filaments solidifies in a cooling shaft after the exit.
• a preparation is carried out at the same time, i.e. Moistening and finishing with antistatic and the like before the filaments are sent to another process.
• the cooling of the liquid filaments emerging from the spinneret has a major influence on the uniformity of titer (Uster value) and on the textile technology properties of fibers and threads in the end product.
• the yarn strength drops as the production speed increases (g / min / hole) (US Pat. No. 4,973,236).
• the cause is insufficient cooling of the melt stream emerging from the nozzle hole.
• the cooling is usually carried out by cross-blowing the filaments.
• the air flow must be low in turbulence and have the same speed across the shaft width so that each filament experiences exactly the same cooling in terms of time and location.
• Perforated sheets or screen mesh in connection with honeycomb rectifiers are used to generate the required flow conditions.
• a speed profile can also be provided over the height of the cooling shaft.
• the object of the present invention is to provide a method which improves the cooling of the spinning melt emerging from the nozzles and thus also enables the spinning of stronger filaments at high speed without crystallite formation occurring in these filaments, which leads to the subsequent stretch - or stretching / texturing process adversely affected. This object is achieved by the features of claim 1 and device claim 12.
• Figure 1 schematically a system for
• FIG. 3 - a graphic representation of the cooling process according to the prior art and according to the invention
• Spinning nozzles 2 from which the filaments F emerge, are arranged on a spinning beam 1.
• these filaments F Before these filaments F, which leave the nozzles 2 in liquid form, can be fed to any further processing, they have to be solidified by cooling, for example to wind them up into bobbins or to deposit them in bundles in cans. They therefore pass through a so-called cooling section SK, on which the threads are guided freely, without touching themselves or other objects, and cooled from the usual melting temperature of approximately 300 ° C. to a limit temperature t, which is approximately 70 ° C. become. Only when this limit temperature t is reached or fallen below, the filaments F may have contact. 3 shows the temperature t of the spinning material in ° C.
• Line t indicates the temperature to which the spinning material must have cooled at least before each contact (limit temperature).
• the cooling conditions are shown, for example, for a polyester POY monofilament with a titer of 22-35 dtex by curve A. The cooling takes place as usual with air which has an intrinsic temperature corresponding to the room temperature of about 20 ° C. The course of the cooling shows that with this type of cooling and a production speed of 3600 m / min the limit temperature of about 70 ° C only after a cooling section SA of about 3.5 m is reached. Only at this distance from the nozzle have the filaments achieved such strength through cooling that they may be in contact with one another or with thread guide elements or the like.
• Curves B and C show the cooling conditions for foam with different volume fractions of liquid. It follows that with a foam with a liquid volume fraction of 5% under the same conditions as for curve A, the cooling distance is shortened to about 1.1 to 1.2 m in order to reach the limit temperature t g . In the case of a higher volume fraction, the cooling distance is shortened further, since the heat transfer also increases sharply depending on the liquid volume fraction in the foam. For example, curve C shows the cooling process for a foam with approximately 10% liquid volume fraction. This reduces the cooling section SK to reach the limit temperature on the section SC, which is less than 1 m.
• FIG. 3 shows the entire cooling process from the exit from the spinnerets to the preparation for the next treatment process.
• the air gap S between the nozzle plate 2 and the foam container 3 a relatively flat course of the drop in temperature can first be seen.
• the cooling curve is considerably steeper than if the cooling were only carried out by air and thus reaches the limit temperature t_ after a short distance.
• a foam container 3 or 30 is arranged under the spinning beam 1 and the nozzle plate 2 at a distance S.
• the distance S can be very small, e.g. only 1 - 2 cm. Its size depends on the filament thickness and production speed. After the filaments F emerge from the nozzles 3 in liquid form, a certain degree of solidification is necessary before they are immersed in the foam. This solidification takes place much faster with fine filaments than with coarser titers, in which this distance from the foam can be up to 1.5 m depending on the production speed.
• the foam container 3 is carried by a frame 32 and has a wide inlet opening 31 at its upper end, so that the filaments F cover the walls of the foam container 3 can not touch while a narrow opening 35 is provided at its lower end through which the filaments F leave the foam container.
• a narrow opening 35 is provided at its lower end through which the filaments F leave the foam container.
• a foam generator 5 is arranged, which has an air supply 51 and a liquid supply 52 and delivers the foam directly into the lower part of the foam container 3. While the foam rises due to the continuous generation of foam, the filaments F are guided in countercurrent from top to bottom through the foam container 3 and emerge from the foam container 3 at the outlet opening 35 in order to then be fed to a further processing process.
• the foam rising upwards is controlled by a sensor 4, which regulates the level, if necessary, via a level controller 41.
• the edge of the upper inlet opening 35 of the foam container 3 is designed as an overflow, so that liquid which regresses can optionally drain off over the edge.
• the overflowing liquid and liquid which forms in the foam container 3 due to regression and flows downward is collected in a collecting trough 33 and returned to the circulating pump 7 via drain lines 36.
• the foam generator 5 is continuously fed by the circulation pump 7, which also effects the circulation of the returned liquid from the foam container 3. Water is supplied to this circuit by the metering pump 72 to the extent that the foaming and cooling of the filaments F liquid is consumed. Preparation oil is added to the liquid by a second pump 71. Both are then pumped through the circulation pump 7 through a mixer 6 and thereby processed into the liquid which is fed to the foam generator 5 via the line 52. In the foam generator 5, air is added to the liquid through the feed 51, thus producing the foam which is delivered to the lower part of the shower container 3.
• the foam container 3 When piecing, the foam container 3 is initially empty. The filaments F emerging from the nozzle 2 fall down into the foam container 3 and are introduced into the outlet opening 35. A flap 34 serves this purpose, which makes the lower part of the foam container 3 accessible. After the introduction of the filament F, the flap 34 is closed again and foam is supplied.
• the sensor 4 controls the rising foam and regulates the motor 42, which drives the metering pump 72 for the water supply, via a controller 41.
• the fill level in the foam container 3, which is controlled by the sensor 4, thus also determines the cooling section SK which the filaments require when the foam passes through.
• the foam bath is used at the same time to apply the preparation solution to the filaments F.
• the system according to the invention thus also includes the required preparation device. Below the foam container 3, the emerging filaments are scanned by two electrodes 8. The constancy of the preparation pad is thus measured via a resistance measurement and, if appropriate, by means of a setpoint / actual value comparison in the concentration controller 81 and a frequency converter 82 which drives the motor 83 for the metering pump 71 for the preparation oil.
• the foam container is designed somewhat differently than in FIG. 1.
• the foam container 30 is designed as a rectangular or cylindrical shaft, to which the foam generator 50, 50 'is attached in a continuation of its outer shape, but separated by a joint 38. , connects.
• the narrow outlet opening 35 of the foam container 3 is here included in the foam generator 50, 50 ', so that the foam container 3 is open at the parting line 38 in its full cross section.
• the foam generator consists of two half-shells 50, 50 ', which can be moved apart in the horizontal direction along the parting line 38. This makes the lower part of the foam container 30 accessible for piecing, so that the falling filaments F can be grasped and inserted in yarn guides for further processing . Once this has been done, the two half-shells 50, 50 'of the foam generator are joined together again, so that they enclose the filaments F and the foam container 30 is closed except for the outlet opening 35 for the filaments F.
• Each of the two half-shells 50, 50 » is designed as an independent foam generator and is connected to both an air supply 51 and a liquid supply 52.
• These feed lines are expediently elastic in order to be able to move the two half-shells 50, 50 'apart.
• sintered metal candles 53 In each of the half-shells 50, 50 'are arranged sintered metal candles 53, through which the air is fed into the liquid.
• a body made of sintered metal can also be supplied for the air supply via a plate or some other form.
• commercially available sintered metal candles are preferably used for the air feed used.
• the use of sintered material results in an extraordinarily good preparation of the liquid with gas, preferably air to foam.
• gas preferably air to foam.
• other fine-pored elements can also be used for the gas supply into the liquid, such as sieves, nozzle plates and the like.
• the liquid level 54 in the foam generator 50, 50 ' is controlled by a level limiter 37 in order to guarantee an even foam production.
• the simplest type of such a sensor 37 is shown by an overflow in FIG. Instead of the overflow 37, a probe can also be provided, which controls the liquid supply in each case.
• the foam produced in this way rises into the foam container 30, while the filaments F pass through the foam container 30 in countercurrent and exit through the outlet opening 35.
• the upper part of the foam container 30 is designed in the same way as in the described embodiment according to FIG. 1.
• the edge of the opening 31 is designed as an overflow, so that the liquid which is recovering can collect and drip off over this edge in order to be collected again and to be returned to the circuit for foam generation.
• a device for smoothing the foam mirror can additionally be provided.
• a suction channel 21 is provided which transports such a foam mountain away or prevents the formation of such a foam mountain by a slight air flow.
• the distance S to the nozzle plate 2 is shown here much less than in FIG. 1. As already mentioned above, this distance depends on the filament speed and the titer of the filaments F. However, a certain distance S must be maintained since the foam blocks the nozzle plate 2 should not touch to avoid undesired cooling of the foam.
• Such a device 21 for smoothing the foam level also requires a certain distance from the nozzle plate.
• Air duct 21 Air duct 21

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Textile Engineering (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
• Treatment Of Fiber Materials (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=7752034

Family Applications (1)

Country Status (6)

Families Citing this family (6)

Family Cites Families (8)

• 1995
  • 1995-01-21 DE DE19501826A patent/DE19501826A1/de not_active Withdrawn
• 1996
  • 1996-01-17 AT AT96900839T patent/ATE193338T1/de not_active IP Right Cessation
  • 1996-01-17 WO PCT/DE1996/000089 patent/WO1996022409A1/fr active IP Right Grant
  • 1996-01-17 JP JP8521974A patent/JPH10501589A/ja active Pending
  • 1996-01-17 US US08/716,408 patent/US5766533A/en not_active Expired - Fee Related
  • 1996-01-17 EP EP96900839A patent/EP0752020B1/fr not_active Expired - Lifetime
  • 1996-01-17 DE DE59605282T patent/DE59605282D1/de not_active Expired - Fee Related

Non-Patent Citations (1)

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