DE102005054653B4 - Apparatus and method for producing melt spun filaments - Google Patents

Abstract

Device for producing melt-spun filaments with a spinning head (3) having at least one spinneret (4) for spinning out the filaments (6) and a cooling chamber (7) provided below the spinner head (3), which is equipped with a blast chamber having a gas feed (10) ( 1) for lateral blowing of the filaments (6) with gas and with a suction chamber (2) arranged opposite the blast chamber (1) with gas discharge (20) for discharging the gas supplied through the filaments (6) and characterized in that at least two in the spinning direction successive combinations of blowing and suction chambers (1, 2) are provided between which at least one separating segment (25) is arranged, which is not connected to a gas supply (10) or gas discharge (20).

Description

The The invention relates to a device for producing melt-spun Filaments according to the preamble of the main claim.

at In melt spinning, polymers are melted as raw materials spinnable under exclusion of air. This is a thermoplastic Raw material in the form of granules or chips by means of an extrusion device to a temperature of at least 5 ° C above the melting temperature of the Polymers heated and over spun a spinning apparatus. Often, the polymer must be prior to its processing be subjected to a drying process to a sufficient to adjust low water content. This is supposed to be an excessive hydrolytic Degradation of the polymer during the melting, the residence time in the melt and the processing to threads avoid. After dosing over Spinning pumps, the melt is forced through spinnerets in a blown air through the spinning shaft. The one from a spinneret emerging jet of a polymer is accelerated under the prevailing withdrawal forces, narrows to the final titer or final diameter and solidifies under the influence of the blowing air. Usually is on one Temperature below the glass transition point of the underlying Polymers cooled, at least but to a temperature at which the thread has sufficient mechanical stability having. The strings are withdrawn from godets, where they are called monofilament d. H. a single filament is spun from a single-hole die or as multifilaments, Here are several threads bundled into a filament strand, may be present. The obtained threads be with a Schmälze or fiber finish provided, possibly still stretched and finally on a winder Speeds of 300-6000 m / min wound into coils. Made in such a way threads can one Titers from 10 to over 2000 dtex, or a diameter of 0.03 to more than 0.5 mm. Under filaments is a textile fiber or a thread of very greater, practically endless length Understood. Under fibers and threads all textile fibers such as filaments and staple fibers, independent of their length Understood.

Of the Cooling a freshly spun thread is of considerable importance too, because through them the mass or titre uniformity as well as the preorientation and thus the textile mechanical properties and the processing quality of the produced Filaments relevant to be influenced. A preferred cooling method in melt spinning is the cross flow or Transverse blowing. In the Queranblasung emerging from the spinnerets be called Filaments in a blow chamber at right angles with air-conditioned and uniformly pressurized air under an adjustable control pressure and cooled. After passing through the filaments, the heated air flow leaves the puffer chamber laterally or frontally over an outlet opening or a grid and mixes with the surrounding room air.

at the Queranblasung takes place the thread cooling according to the principle of Shell and tube cross-flow heat exchanger. The used air flow should be laminar and low turbulence and a substantially uniform flow velocity to cool to all Have filaments, so that all threads undergo an identical cooling. For generating the blowing air flow are in the blow chambers perforated fabric or mesh often in Connection with honeycomb rectifiers installed. About the height of the blow chambers is the cooling section for the Filaments set, over The structure of the rectifier can be a specific speed profile for the Blowing air can be specified. The speed of the blown air is through the prevailing form with the conditioned air of the blow chamber supplied is regulated. It can be air speeds of 0.1 to 0.5 m / s in some cases generate and set up to 1.0 m / s. The blow chambers point at least one width over the entire width of the cooled Threads on. Usually become blowing lengths from 0.5 to 2 m in rare cases used up to 3 m. The transverse blowing in melt spinning will both in filament spinning as well as in staple fiber production used and is widely used. In the filament spinning can both Multifils and monofilaments are cooled. The used Blow chambers can be made very variable, their maintenance and procurement costs are in comparison to other cooling methods low.

Furthermore are the expert further Abkühlverfahren for the Melt spinning known, such as. B. indoor / outdoor or outdoor / Innenanblasung, at the conditioned blown air diametrically over the emerging filaments is directed. To the general principles and the state of the art for Melt spinning and cooling the filaments are printed on F. Fourné, "Synthetic Fibers", Hauser Verlag, Munich, 3rd edition, 1995 ISBN 3-446-16058-2, p 348 ff. Referenced.

A disadvantage of the conventional method of Querluftanblasung is that the exiting the blow duct air gaseous emissions such. B. may contain spider smoke or liquid or solid condensates. These substances may be precursors, monomers, oligomers or degradation products resulting from hydrolysis, oxidative or thermal degradation from the starting polymer. Furthermore, evaporation can conditions of additives such as stabilizers, additives, plasticizers, etc. originate. The released substances often have a health-endangering effect, their delivery to the ambient air should therefore be avoided.

One Another disadvantage of conventional Thread cooling systems is that they usually with sucked, fresh outside air operate. Before being used as blast air, the fresh air in appropriately dimensioned air conditioners on the procedural side conditions for the temperature and the moisture content are conditioned. Depending on prevailing climatic conditions need for cooling or warming of the Outdoor air large amounts of energy be spent.

Of Another is the conventional one Queranblasung only conditionally for the cooling off of monofilaments with high titers (> 100 dtex). A possibility To achieve this is to increase the Queranblaslängen of usually 120-200 cm to about 300 cm or above out. A disadvantage of such an embodiment, however, is that the cooled with it Filaments relatively strongly deflected from the natural fall line become. Under the natural Case line is understood to mean the vertical drop of a filament from a spinneret without Influence of a deflecting force or a deflection caused by touching with a thread guide. Due to the air resistance of a filament strand but this is dependent its diameter, strength, take-off speed and flow velocity the blowing air from its natural Case line deflected. Opposite is a returning force, because the run of the filaments by Fadenleitorgane, preparation facilities or the spinning machine has to be stabilized. It results in one arcuate (C-shaped) Deflection of the filaments, with the maximum of the deflection, beside the above influencing factors, also strongly on the length of the Blaslufteinwirkung and thus on the height of a blow chamber depends. Around at an extension a blow chamber or raise the blowing air velocity, a bumping or streaking of the filaments on the blow chamber wall or the air outlet grille to avoid have to the blow chambers corresponding further in the Blasluftströmungsrichtung be dimensioned. This is at the expense of the available Spinnereirau with, as the Spinnköpfe and Spooling machines set up with a correspondingly larger distance Need to become. Furthermore is the extension the blow chamber disadvantageous in one-sided air supply, since the yarn path through the stronger one Deflection becomes unstable, resulting in higher intrafilament titer fluctuations can result.

Stand for reasons of space no extended blow chambers to disposal or should be produced hochtitrige monofilaments, then the spun filaments in a water bath or in a combination of air cooling and water bath cooled become. This kind of cooling But is much more complicated than the cooling with air and is usually only performed at low yarn withdrawal speeds.

From patent US 2,273,105 A It is known that a laminar cooling air blown in transversely to the filaments produced is an effective method of thread cooling in melt spinning. In a specific embodiment of the invention, the principle of opposing air flows in a blow chamber to achieve a more intense and thus faster Fadenabkühlung is shown. The ability to actively remove the injected cooling air is not disclosed. It is expected that due to the insufficient delineation of directly on one of the subsequent puffer segments with different Blasluftströmungsrichtung due to strong turbulence deterioration of the thread uniformity over the use of only a single Blaskammersegments occurs.

Also known is from DE 195 14 866 A1 that an improvement in the uniformity of the cooling air flow in the edge regions of a filament bundle can be achieved if the cooling air flow limiting outer walls are provided with air passage openings. However, for this purpose, the laterally limited walls are provided with openings parallel to the flow direction of the injected air and connected to an exhaust. In this case, however, a uniform and rectilinear laminar flow through the emerging from the spinning head filaments is not guaranteed, which in comparison to a suction device opposite the Blaslufteinströmfläche greater titer fluctuations are expected. The used cooling air is sucked off only in a small amount.

From patent US 4,943,220 A a device for influencing the flow direction of the injected cooling air is known. Movable flaps are used, which limit the cooling air flow laterally and thus to reduce free passage of the cooling air between the outer filaments and the Blaskammwand. It should result in a better homogenization of the cooling air and therefore a better cooling effect. However, a problem with this embodiment of the blow chambers, a possible abutment of the filaments must be considered at the boundary flaps, which would have a significantly increased thread breakage rate.

The DE 198 21 778 A1 describes an advance towards the production of microfilaments, with which a higher titer uniformity in multifilaments over the standard cross-flow blowing is achieved by means of an inside-Außenanströmung and a sinked into the sense bar and thus thermally insulated spinneret plate.

From the DE 195 04 671 C1 is also a Vorrich device for the production of melt-spun filament filaments known. This device has a spinneret for spinning the filaments having spinning head and a cooling chamber arranged below it.

Other apparatus and methods for making melt spun filaments are known from US 5,156,062 DE 690 12 786 T2 . DE 16 60 682 A as well as the DE 14 35 476 A known.

Of the Invention is based on the object, a device for manufacturing to provide melt-spun filaments that allow for efficient cooling Queranblasen with reduced delivery harmful Allowed substances to the surrounding room air.

The The object is achieved by the characterizing features of the main claim in connection with the Characteristics of the preamble solved.

According to the invention the cooling off the filaments in a combination of a blow chamber with a opposite Suction chamber or by several successive combinations of suction and blow chambers. The resulting during spinning are Spider smoke or also emerging from the hot polymer melt vapors or Gases or even during spinning in particular of isocyanate and / or urethane group-containing raw materials occurring harmful iocyanhathaltige fumes with the blown air effectively dissipated and do not get into the ambient or indoor air. The from the suction chamber discharged suction air can from the harmful Substances cleaned and in their entirety or partially after mixing with fresh air with less Energieauf wall again used as blowing air for the thread cooling become. The invention is suitable for cooling both mono- as also multifilaments. Due to the suction by the particular also more directed in the edge regions of the thread cooling chamber guide the blown air, all filaments, d. H. the entire group of filaments, evenly Blowing air flows through and cooled. This results in lower interfilament titer fluctuations. On the Use of limiters or baffles in the area the thread cooling chamber can be omitted, because the cooling air is also in the edge areas of high uniformity and a homogeneous flow rate having.

By in the subclaims specified measures Advantageous developments and improvements are possible.

Advantageous For the purposes of the invention, it is the opposite when used directed blowing currents in two consecutive blow chambers, preferably in combination with an opposite one Suction chamber, a lower belly of the blown with cooling air thread or sets the yarn sheet and thus a lower deflection the to be cooled Filaments from the ideal vertical fall line results. Especially This is an option monofilament with a titer> 100 dtex effectively over the entire blown air length cool. This allows Blow chambers of lesser depth are used, creating a space-saving Arrangement of spinning machines allows becomes. Surprised has continued to show that due to the lower deflection and the more stable yarn path of the resulting S-shaped yarn sheet as well as the more even and less turbulence-prone blown air by the in flow direction supportive acting suction achieved lower intrafilament titer fluctuations can be than when using a blow chamber comparable blow-off after the conventional principle the Queranblasung possible.

in the Meaning of the invention both conditioned air and inert gases, such. B. carbon dioxide, Nitrogen or noble gases as well as reactive or reaction-promoting Gases, such. As oxygen, ozone, nitrogen oxides or water vapor in the Whole or mixed in parts of the blowing air and used in the thread cooling become. Due to the largely closed and sealed construction the cooling chamber with the blowing and Suction chamber are cooling or reaction gases or due to the action of reaction-promoting Gases or vaporous Compounds resulting reaction products no longer or only in negligible Extent in the ambient air of Spinnereiraums delivered. A health hazard can thus be avoided.

In Advantageously, below the spinning head, d. H. below the exit point of the filaments from the nozzle bores a flow-calmed Zone or an area with only slight air movement without active Fadenfühlung intended. Because of this flow-calmed Zone the filaments are better spun out.

According to the invention is min. Between several combinations of blowing and suction least a separating segment without gas supply or removal provided. As a result, turbulence between different gas flows are avoided, whereby lower titer fluctuations, in particular intrafilamantärer be realized.

Farther is particularly advantageous, a return of the extracted cooling air in provide the blow chamber (s), where appropriate after cleaning, since this can save energy, d. h., a lesser one Energy consumption for thread cooling resuliert.

The Invention leaves apply to all melt-spinnable thermoplastic polymers, or other polymers that undergo a melt spinning process to process filaments. These include u. a. Polymers from the Group of polyesters such as polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), Polytrimethylene naphthalate, polybutylene naphthalate, polylactic acid (PLA), furthermore all Polyesters consisting of linear or branched, aliphatic or aromatic diols having 2 to 12 carbon atoms and polyethers or their mixtures and linear or branched, aliphatic or aromatic dicarboxylic acids with 2-20 C-atoms or their mixtures or from OH-containing Carboxylic acid compounds with 2-20 C-atoms produced. The polyesters can be linear be constructed or chain branches have. The polyesters can used in their pure form or as mixed and co-polyester as they are produced directly by mixing the starting components or by mixing the polymers or by mixing appropriate polymer melts accessible are. Another group of polymers that are within the meaning of the invention advantageously spin, the polyamides are by polyaddition accessible from lactams are such as the polyamide 4, polyamide 6, polyamide 11, polyamide 12, furthermore all polyamides like the polyamide 66, which consists of linear or branched, aliphatic or aromatic diamines having 2 to 12 C atoms and linear, branched, aliphatic or aromatic dicarboxylic acids having 2-20 C atoms or their Make mixtures. The polyamides can be linear or chain branches. The polyamides can be used in their pure form or used as a mixture of co-polyamides, as they are directly produced by mixing the starting components or by mixing the polymers or by mixing the polymer melts accessible are.

A Next group of polymers which are advantageous in the context of the invention can be spun, is the group of polyolefins. Here can Homopolymers of polyethylene or polypropylene or copolymers the polyolefins with a proportion of co-monomers such as ethene, propene, Butene, pentene, hexene, pepten, octene, decene, styrene, etc. act. The Polyolefins can be linear or chain branches have. The polyolefins can be used in their pure form or used as mixed and co-polyolefins as they are made directly by mixing the starting components or by mixing the polymers or by mixing the polymer melts are accessible.

Of Further can For the purposes of the invention advantageously spun polymers the groups of the polycarbonates, the halogenated vinyl polymers or the block copolymers based on styrene and butadiene.

All Polymers which advantageously spin according to the invention let, can in the form of the pure polymer or in any mixture with one or more polymers, by themselves individually also advantageous in the context of the invention spinnable are. Furthermore you can the polymer to be spun or the polymer mixture additives and Aggregates in pure form or in mixtures up to a quantity be added, which is a spinning of the resulting melt allowed. The aggregates can in liquid or solid form or preprocessed to a masterbatch to the polymer or its melt can be added. For the additives and additives can for example, stabilizers, matting agents, Pigments, dyes, fillers, melt aids, Further processing aids or reaction components act, as they are known in the art.

Especially Advantageously, the invention for the Melt spinning of elastic threads be used. Under elastic threads are filaments with a high elongation and high recovery, d. H. with a small remaining residual strain after lifting the understood as strain-causing force. Be elastic filaments z. B. stretched to twice their original length, so should after removal the strain-causing force is not the permanent stretch of the thread piece more than 50% of the original Length amount. It is believed that elasticity of the material on a phase separation of hard and soft segments, with those in the soft segments in a coiled Form present macromolecule chains under a long line Orient force and after lifting the force try in the originally reorient the previous preferred ball shape. Elastic threads Nowadays, dry, wet or melt spinning processes are used generated.

In younger Time has melt spinning of elastic filaments gained in importance. This is a thermoplastic raw material, which is more elastic for the production Threads suitable is melted, and the melt obtained via one or more nozzle holes extruded into filaments which are cooled with air in transverse blowing. It can both mono- and multifilaments are produced. The preferred Packaging of elastic threads from a melt spinning process are monofilaments in the titer range 11-78 dtex, which are at spinning speeds in the range 300-800 m / min are produced. In contrast to the conventional dry spinning process, can melt spinning on the use of a solvent be waived.

It are a range of thermoplastic raw materials for melt spinning elastic filaments available, such as B. thermoplastic polyurethanes (TPU), polyether esters (PEE), Polyetheramides (PEA) or polyolefins (PO) with elastic properties. TPU raw materials for producing melt-spun elastic Threads are made from the raw materials of the following groups. A raw material the group of polydiols with a molecular weight between 500 and 4000 g / mol, usually a polyether diol, polyester diol or a polycaprolactone, a Raw materials of the group of aromatic or aliphatic polyisocyanates such as z. As the bis-diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) or the methylene bis (cyclohexyl) diisocyanate and a short chain chain length rer the group of low molecular weight diols having a molecular weight <400 g / mol such. As the ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol or 1,4-benzenedimethanol. The raw materials of each group can be found in pure form or mixed with one another without the group of thermoplastic polyurethanes used in the sense of Advantageously, the present invention can be spun onto the mentioned examples or raw materials is limited or limited. The TPU polymers are prepared by methods known in the art made and can Additives and additives such as stabilizers, Matting agents, pigments, dyes, fillers, melt aids or Processing aids.

The mentioned above Advantages also apply in particular to the elastic filaments, d. h., by the use of opposing directed blast air flows in several consecutive blow chambers will have a lower maximum Deflection of the cooled Filaments reached, whereby the solidifying and still low Thread strength envisaging Filaments are subjected to less stress, resulting in the use of longer zones with an active blowing allowed than this with a conventional one Queranblasung and thread cooling from only one side is feasible. Within the meaning of the invention can be elastic Monofilaments up to about a titer of 300 dtex when using at least two consecutive following blow chambers with opposite Blasluftströmung Withdrawal speeds of up to 1000 m / min can be produced.

embodiments The invention are illustrated in the drawing tion and are in the following description explained. Show it:

1 a view of a spinning head with underlying indicated Blaskammer,

2 a schematic section through a cooling chamber with blowing and suction chamber and indicated spinning head,

3 a perspective view of a cooling chamber with blowing and suction chamber, and

4 a schematic sectional view through a spinning shaft with cooling chamber and two successive combinations of blowing and suction chamber, and

5 a schematic representation of a plant for producing elastic filaments.

With reference to the 1 - 3 For example, the spinning apparatus of the present invention has a spinner head 3 on, with a plurality of spinnerets or spin packs 4 equipped. From the spinnerets 4 in each case a single filament 6 or more filaments. The spinnerets 4 are offset and spaced from each other, wherein a is the thread pitch or the pitch is defined, which are defined as the distance between the spinneret 4 exiting single filaments 6 when projecting onto a surface parallel to the row of spinnerets in the spinner 3 , Every single spinner 3 is through insulation 5 thermally insulated in the area of the bottom of the spinnerets 4 is omitted, to a simple installation and removal of the spinnerets 4 to enable.

Below the spinning head 3 closes a spin shaft 31 (S. 4 ), being part of the spin shaft 31 a thread cooling chamber 7 is. The chamber 7 has two opposite side walls 14 with a smooth surface or with a surface that avoids the emergence of turbulent air currents or air swirls, with the other two opposite surfaces are open and each in an attached puffer chamber 1 and a scheduled suction chamber 2 pass. Of course, side walls may be provided with large openings for connection to the blow chamber 1 and to the suction chamber 2 are provided. Blowing and suction chamber 1 . 2 are closed to the outside and each have a gas or air supply 10 and a gas or air discharge 20 on. The supplied air is with 10 ' designated and the discharged air or the discharged gas is with 20 ' designated.

The cooling chamber 7 with the side walls 14 and the blow chamber 1 and the suction chamber 2 is optionally with the use of a box or tubular intermediate part of the spinning head 3 recognized, with all parts are sealed to each other and to the environment. How out 1 It can be seen, the width of the opening between the puffer chamber 1 and the cooling chamber 7 such that blown air over substantially the entire width of the cooling chamber 7 , that is introduced over the width b of the exiting yarn sheet and in addition to the two edges over a width f. The blow chamber 1 has a length l that can be variably designed and adapted to the process conditions. High titer monofilaments require longer cooling distances, which are achieved with the invention, so that the length l is up to 4 m and optionally more.

Between the exit point of the filaments from nozzle bores of a nozzle plate of the spinneret 4 and the upper edge of the blow chamber is a flow-calmed zone 8th provided that is not designed directly from the blow chamber 1 in the cooling chamber entering blowing or cooling air is flown. The design of the flow-calm zone 8th may be such that it is divided into areas about each a single filament or a group of filaments or as an area around all of a spinner 3 emerging filaments is formed. The height c of the flow-calm zone 8th , in which no active cooling of the freshly spun filaments is supplied with blowing air, begins immediately after the nozzle plate.

The flow-calmed zone 8th can be obtained when the thread cooling chamber 7 not directly connected to the spinning shaft. For this purpose, the above-mentioned box or tubular, only open in the direction of yarn passage transition piece between the spinning head and the cooling chamber can be used. In 2 becomes the flow-calmed zone 8th through insulating layers 5 given to the spinnerets 4 or the spinning head are attached. The insulating layers can be formed, extended or narrowed by thread-permeable hollow bodies arranged in the thread running direction, thereby adapting to the process-required height c of the flow-calmed zone 8th is possible. In another embodiment, the spinnerets are retracted into the spinner head. Finally, a flow-calmed zone 8th also by a between the spinning head 3 and the thread cooling chamber 7 introduced actively heated reheater to be created.

The dimensions of the spinning head 3 with nozzles, the cooling chamber 7 and the blow chamber (s) are sized so that at the blowing speeds used, contacting the spun filaments with the walls of the cooling chamber 7 or other installations is avoided.

As in 3 can be seen, in at least one of the side walls a closable opening or door 16 which allows access to the nozzles for their installation and removal or for inspections and cleaning. In addition, one or more lenses are in the sidewall 14 provided, via which a visual inspection of the filament exit from the nozzle plates or the thread run in the thread cooling chamber 7 given is.

The suction chamber 2 lies the blow chamber 1 opposite, wherein preferably the flow area between the cooling chamber 7 and the suction chamber 2 the flow area between the blow chamber 1 and cooling chamber corresponds. However, other dimensions are possible, which are given for example constructively. There may also be a different number of blow chambers to the suction chamber (s), for example, two blow chambers can only face a suction chamber with a larger flow area. The gas discharge 20 from the suction chamber 2 is connected to a suction fan, not shown, whose suction power according to the over the blow chamber 1 added and sucked gas quantities is set.

In the area of the feeder 10 the blow chamber 1 is a control device 11 arranged, which can be designed as a flap, slide or aperture. A corresponding control device 22 is in the gas or air discharge 20 the suction chamber 2 arranged. About these control devices 11 and 22 , which operate separately from each other, the amounts of the supplied blast air and the gases to be sucked and thus the resulting velocity of the blast air in the cooling chamber 7 set. Preferably, the respective control device is designed so that the amount of air supplied or the discharged gases can be adjusted continuously between 100% and 0% based on the back pressure before each control device. In the exemplary embodiment, the governing flow parameter is the flow velocity in the cooling chamber and then the equilibrium between supplied and discharged air is turned on provides. Before or after the control device 11 in the Blasluftzuführung an interchangeable filter can be introduced into the air flow, which allows pre-cleaning of the incoming air into the Zuluftkammer.

Both in the flow area of the blow chamber 1 to the cooling chamber 7 as well as in the flow area between the cooling chamber 7 and suction chamber 2 are rectifier or rectifier elements 12 and 19 arranged, which allow a homogenization or a profile formation of the flow. The rectifier 12 . 19 with their elements consist of porous, air-permeable materials, such. As pinhole, honeycomb, fabric, tiles, mats or filters made of metal, plastic or textiles. On the nature, thickness and porosity of the rectifier elements or their combination, the pressure loss is defined and, together with the aforementioned adjustment and control options, the flow velocity of the blown air in the yarn cooling chamber 7 set. For mechanical stabilization and protection of the rectifier 12 . 19 each damage are protective grille 13 . 17 arranged, which have only a low air resistance, wherein the protective grid 17 also avoids unintentional sucking of filaments in the suction chamber. In addition, an exchangeable separator fabric 18 (please refer 4 ) are exchangeably mounted in the form of a wire mesh or a textile or paper covering, on which also the condensable vapors emerging from the filaments during the spinning process can be deposited.

In 4 is shown a further embodiment of the device according to the invention. The device has two successive combinations of puffing chamber 1 and opposite suction chamber 2 on, wherein between the combinations a separation segment 25 is used, which is designed as a filament running open tube or open box. It has the same dimensions as the thread cooling chamber 7 , However, if the successive combinations of blow chamber 1 and suction chamber 2 have different dimensions, it can be designed as a continuous transition element. The separation segment 25 is not actively flowed by blowing air and is not connected to a suction. The height of the separation segment 25 is to be chosen so that no turbulence through the various z. B. counterflow currents occur. At the separation segment can rails, bars or heels 24 or movable flaps or plates attached, with the help of which the cooling chamber 7 can be separated according to the combination of suction and puffing, this separation for the duration of the adjustment of the ratio of supplied blown air and to be removed suction air for a combinati on serves. On the heels 24 plates or sheets are placed tightly for separating the cooling chamber sections, whereby the exchange of air between the Fadenkühlkammerabschnitten is prevented.

In the illustrated embodiment, the flow directions of the upper combination are blowing chambers 1 -Saugkammer 2 and the underlying combination opposite to each other, ie below the blow chamber 1 the upper combination is the suction chamber 2 the lower combination and below the suction chamber 2 the upper combination is the blow chamber 1 the lower combination.

The spin shaft 31 to which the cooling chamber 7 heard, sits below the lower combination through a downpipe 23 continues and is at the bottom by a closure device 27 , completed for example in the form of movable flaps or rails guided panels. Between the lower combination blow chamber / suction chamber and the downpipe 23 are also paragraphs 24 for holding sheets or plates available. To thread guide are Fadenleitorgane 28 and for pulling the threads is a trigger device 26 that z. B. is designed as godets provided.

The operation of the devices accordingly 1 to 4 is as follows.

The filaments to be cooled 6 respectively. 29 be in the spinning head 3 or more in a spinning beam arranged spinning heads, wherein they are through nozzle bores, which are individually or in groups in nozzle plates, in the thread cooling chamber 7 pressed. The individual spinnerets or spin packs 4 are appropriate 1 arranged in rows, so that the individual nozzle holes in blowing air direction 10 seen offset from each other. The individual filaments 6 go through the thread cooling chamber 7 thus staggered and the defined thread spacing a to each other, so that each filament can be uniformly flowed with cooling air. The spinner 3 can be a plurality of spin packages 4 have, in 1 There are three rows shown. The spun filaments 6 pass the flow-calmed zone 8th in which they decrease in diameter and then enter the cooling chamber 7 in which they correspond accordingly 2 transverse, ie are blown perpendicular to the thread running direction over the entire filament width with blown air. They become C-shaped out of the fall line 6a deflected.

In 4 the blowing air is in each case in the upper and lower blow chamber 1 blown in opposite directions of flow. This will make the filaments 29 less strong from their ideal fall line 6a deflected. It turns an S-shaped profile of the threadline.

About the feeder (s) 10 Pressure- or volume-controlled conditioned air is introduced into the blow chamber (s). The conditioned air can z. B. be provided by an air conditioner, wherein a fan device with connected duct system, the air evenly on all connected blow chambers 1 distributed. The blast air flows through the cooling chamber 7 , takes any resulting gases with and is via the suction chamber 2 discharged again. The regulation of the ratio of the amount of supplied blowing air to discharged suction air was determined prior to spinning, wherein each cooling chamber section by itself by providing the sealable plates by means of the control devices 11 . 22 and the suction power of the blower is adjusted. The amount of suction air discharged from each yarn cooling chamber section corresponds to 50% to 120% of the supplied blast air, advantageously 90% to 110%. If the smallest possible intrafilament titer fluctuations are intended, the blown air is supplied with a small excess to the amount of sucked suction air. The slight excess of blast air can be due to a closable hole in the area of the thread cooling chamber 7 be measured in the form of an outgoing air flow, wherein the measurement or the separating plates on the paragraphs 24 are set up. By means of a at a resealable opening 30 connected pressure gauge is an overpressure in the yarn cooling chamber 7 from 0.1 to 5 mm of water, measured at a preferred setting of 0.3 to 1 mm of water. In addition, a measuring head of an air flow meter through the closable opening 30 be introduced into the yarn cooling chamber for the duration of the measurement in order to determine the flow velocity of the blown air, which is measurable at any time without a separating plate.

If more air is discharged from the yarn cooling chamber section than blowing air over the blowing chamber 1 flows in, as z. B. is necessary for the removal of used during the spinning or cooling process or leaked hazardous substances, the prevailing in a largely hermetically sealed thread cooling chamber section negative pressure can also be determined by means of a connected pressure gauge. For the purposes of the invention, negative pressures of from 0.1 to 5 mm of water are used, preferably from 0.3 to 3 mm of water. Under a weitge starting hermetically sealed thread cooling chamber or a thread cooling chamber section is to be understood that at least 70%, preferably at least 90% of the inflowing in the yarn cooling air blowing air is removed on the suction side, so that a maximum of 30%, preferably at most 10% of the supplied Blasluftmenge to the surrounding air be delivered. Will more air from the thread cooling chamber 7 aspirated as blowing air was supplied to the excess amount of extracted air over the open area of the spinning shaft 31 sucked.

The separation segment 25 between the two combinations prevents blast air flows of non-directional or turbulent profile or blast air vortex from being generated at the interface of two adjacent thread cooling sections, as may arise when the sections are operated at different blast air velocities or differently oriented blast air flows.

After leaving the yarn cooling chamber section considered in the thread running direction, the filaments still pass through the downpipe 23 ie an area in the spin shaft 31 without active Queranblasung in which a further thread cooling can take place, for. B. by the over the spin shaft 31 sucked air during operation of the thread cooling chambers by means of a set negative pressure or by the air flowing out with the filaments at a set overpressure in the spinning shaft 31 , This downpipe 23 is formed as a pipe or as a rectangular channel, wherein its height is selected so that ordered air flows to achieve uniformity in the lower region are present. The spin shaft 31 itself can narrow in the direction of the thread withdrawal direction.

The closure device 27 is designed so that it can be easily adapted to the yarn path under changing spinning conditions in order to avoid reliably abutting the filaments against the wall of the closure device. At the same time, the area and thus the speed of the spin shaft 23 incoming or outgoing air are regulated. Excessively high air currents in this area are unfavorable, since this can lead to fluttering of the threads, which manifests itself in higher titer fluctuations.

The suction chambers 2 can each be connected individually or together to a suction device or a suction fan. In the latter case are several suction chamber 2 connected to the suction fan via an air distribution system. Scrubbers, separators or adsorption devices, which may be part of a suction device, allow a cleaning of the suction air and a removal of the exhalations, which may arise during the spinning of the filaments. Preferably, together with the suction air reaction products from the polymer melt or polymer components with a gaseous or vaporous reactant forming reaction products are removed, which are also subsequently removed from the suction air. The suction air can be cleaned or be discharged unpurified as exhaust air to the environment. Preferably, however, the suction air is mixed directly or in parts with fresh air, reused with less energy than blowing air for thread cooling.

In 5 there is shown a plant for producing melt spinnable elastic filaments using a cooling chamber according to the invention.

The plant has a dryer 40 for drying the raw materials used, for. TPU, PEE, PEA or PO. The dryer 40 is with a melt extruder 41 connected to transfer the pipe materials in a melt. a mixing device 43 mixes the melt from the extruder 41 with a prepolymer via a metering pump 46 is supplied. The thus prepared melt is distributed to the connected spinning heads, with spinning pumps 42 the supply of the spin packs with a defined volume flow of melt. The spun filaments are warped after leaving the nozzle bore, accelerated to the take-off speed and in the cooling chamber 7 corresponding 4 cooled with the directed blast air, with the resulting gases through the suction chamber 2 subtracted from.

isocyanate fumes or isocyanate-containing volatile Connections made of TPU can for example, unreacted monomeric raw materials of the group the diisocyanates or in the reaction of diisocyanates with OH-containing compounds resulting oligomers. by virtue of the temperatures required by the melt spinning process of TPU about 160-260 ° C and the Dwell time of the melt at these temperatures form beyond under the prevailing balance of the formation and fission reaction the urethane groups again isocyanate group-bearing compounds, which may be volatile under the prevailing spinning conditions. Especially but a heavy load of the spent blast air is observed when to produce the TPU elastic filaments of a melt a TPU a so-called TPU prepolymer is added. Under a TPU prepolymer or prepolymer is in this case the reaction product of Raw materials from the group of diisocyanates with raw materials from the Group of diols, especially the group of polydiole understood. The usual melt-spinning of TPU used prepolymers or prepolymer blends have a molecular weight of 400-4000 g / mol and wear predominantly at their chain ends reactive isocyanate groups.

It is believed that the addition of prepolymer compounds to a TPU melt results in an increase in molecular weight as well as crosslinking of the hard segments in the TPU, resulting in better elastic properties and higher thermostability of the spun yarns compared to such TPU yarns without Prepolymer addition can be made. The addition of the prepolymer can be carried out at any time after transfer of the TPU in a melt, in the present embodiment, the mixing device 43 is used.

A homogeneous mixing of the prepolymer into the TPU melt is desirable, as this results in uniform yarn properties. Usually, between 5 and 25% by weight, in a preferred embodiment, between 10 and 20% by mass of a prepolymer or a prepolymer mixture is added to the TPU melt. Before its addition, the prepolymer must be protected from atmospheric moisture in order to prevent premature reaction and thus inactivation of the isocyanate groups. For this purpose, the storage of the prepolymer has under nitrogen and stirring under stirring in a heated storage tank 44 proved to be suitable. From this reservoir from the prepolymer is conveyed via a heated line in the TPU melt.

In the described embodiment of the invention, the production of melt-spun elastic threads based on polyurethane-containing raw materials with the addition of the prepolymer to the TPU melt via the combination of two successively arranged and interconnected via a heated melt line gear pumps. The first pump considered in the direction of delivery and as a booster pump 45 referred to, is doing with a low pre-pressure prepolymer from the reservoir 44 fed. The low pre-pressure of 0.1 to 5 bar can be due to the hydrostatic pressure of a mounted on the outlet area of the storage container line with a rise height of up to 10 meters or by applying an overpressure by means of an inert, largely anhydrous gas of up to 5 bar at the Reservoir or by a combination of hydrostatic pressure and applied pressure on the pressure-tight lockable reservoir can be applied. A gear pump fed under such a low pre-pressure is able to introduce the prepolymer into a melt of TPU up to a back pressure of 250 bar, but the delivery constancy is low and decreases with increasing back pressure. In a preferred embodiment of the invention, the first prepolymer pump feeds as a booster pump 45 the connected dosing pump 46 , which is also designed as a gear pump with a sufficiently high inlet pressure, the safe and uniform promotion of the prepolymer in a TPU melt to a back pressure of 250 bar allowed. The regulation of the inlet pressure of the metering pumps is performed by a pressure-speed control known in the art, in which the drive speed of the booster pump is controlled and maintained depending on the pressure prevailing before a metering pump or alternatively as a function of the output pressure of the booster pump to a constant setpoint.

Corresponding 5 feeds the booster pump 45 a heated ring pipe 47 , to which at least the metering pump 46 , in a preferred embodiment, several Prepolymerdosierpumpen 46 are connected. To ensure a sufficiently high pre-pressure and thus sufficient filling of all connected dosing pumps, behind the last dosing pump is a resistance element 48 in the ring line 47 brought in. The resistance element is in the embodiment of a pitot tube with a narrowed pipe cross-section or a set screw, which also narrows the line cross-section. Prepolymer containing the loop 47 has flowed through and not from the metering pumps 46 was removed, passes through the resistance element 48 back to the reservoir 44 and from there again the ring line 47 be supplied.

The advancement the prepolymer in a loop is advantageous because the prepolymer central, in a part of the melt production separated from the Plant is stored and from there to the individual addition points can be distributed. This is the handling of prepolymer avoided multiple points in the plant, which is often critical, since in the area Spinning the space cramped with canisters or barrels is thus difficult and Prepolymer during filling and decanting easily spilled can be. This is particularly critical, since this is harmful isocyanate group-containing fumes can escape. Furthermore, the prepolymers are usually very sticky, honey-viscous liquids, which cause sticking on spinning equipment and building components tend and later in Presence of water or atmospheric water vapor to one abreact solid, difficult to remove mass. The cleaning of Prepolymer contamination is laborious and labor intensive and should therefore be avoided.

Another advantage of the central storage of the propolymer is that the average residence time of the prepolymer under elevated temperature in the reservoir 44 can be kept short, so that the Abreagieren and unusable the reactive isocyanate groups not or only to a lesser extent compared to the storage and feeding only one point of addition occurs. An advantage of this embodiment of the Prepolymerdosierung is also that when parking one or more metering pumps 46 due to the still possible flow of the prepolymer in the loop 47 Clogging in the loop can be effectively reduced due to the formation of agglomerates of prepolymer. The formation of agglomerates occurs in particular when standing of prepolymer in the reservoir 44 or lines due to self-reaction of the prepolymer or by reaction with atmospheric moisture to crosslinked polymer structures.

Claims (19)

Device for producing melt-spun filaments with at least one spinneret ( 4 ) for spinning out the filaments ( 6 ) having a spinning head ( 3 ) and one below the spinning head ( 3 ) provided cooling chamber ( 7 ) connected to a gas supply ( 10 ) having blow chamber ( 1 ) for lateral blowing of the filaments ( 6 ) with gas and with one opposite the blow chamber ( 1 ) arranged suction chamber ( 2 ) with gas discharge ( 20 ) for discharging the supplied and by the filaments ( 6 ) by flowing gas is characterized in that at least two in the spinning direction successive combinations of blowing and suction chambers ( 1 . 2 ) are provided, between which at least one separating segment ( 25 ), which is not connected to a gas supply ( 10 ) or gas removal ( 20 ) connected is. Apparatus according to claim 1, characterized in that each blow chamber ( 1 ) a gas supply ( 10 ) and each suction chamber ( 2 ) a gas discharge ( 20 ) assigned. Apparatus according to claim 1 or 2, characterized in that the respective gas supply ( 10 ) and / or gas removal ( 20 ) a regulating device ( 11 ) assigned. Apparatus according to claim 3, characterized in that the speed of the gas flow via the supply of the gas is adjustable and controllable such that a speed in the cooling chamber ( 7 ) of 0.1 and 1.0 m / s. Device according to one of claims 1 to 4, characterized in that in the blow chamber ( 1 ) and / or suction chamber ( 2 ) Rectifier elements, baffle elements and / or flow-leading and / or gleichmäßende internals for equalization and / or profiling of the flow are arranged. Device according to one of claims 1 to 5, characterized in that the cooling chamber ( 7 ) and its associated blow and suction chambers ( 1 . 2 ) are sealed against ambient air. Device according to one of claims 1 to 6, characterized in that the gas discharge ( 20 ) a suction fan for sucking a quantity of the over the blow chamber ( 1 ) supplied gas between 50% and 120% is connected. Device according to one of claims 1 to 7, characterized in that between cooling chamber ( 7 ) and blow chamber ( 1 ) and / or suction chamber ( 2 ) Filter elements and / or separator elements ( 18 ) are provided, which are used for filtering the gas and / or for the deposition of condensables. Device according to claim 8, characterized in that that the filter elements and separator elements consist of a wire, Fiber, textile or knitted fabric or made of paper. Device according to one of claims 1 to 9, characterized in that when several combinations of blowing and suction chambers ( 1 . 2 ) successively different gas flows, preferably opposite gas flows and / or different gas velocities are provided. Device according to one of claims 1 to 10, characterized in that the cooling chamber ( 7 ) shaft-shaped in a sealed manner to the spinning head ( 3 ) is attached and has openings in two opposite walls, on the one hand the blow chambers ( 1 ) and on the other hand, the suction chamber ( 2 ), optionally several suction chambers are attached. Device according to one of claims 1 to 11, characterized in that a plurality of spinnerets ( 4 ) in a spinning head ( 3 ) are arranged and that the flow area between the blow chamber ( 1 ) and cooling chamber ( 7 ) at least the width of the spinner ( 3 ) has emergent thread group. Device according to one of claims 1 to 12, characterized in that between spinner ( 3 ) and cooling chamber ( 7 ) with blowing and suction chamber ( 1 . 2 ) a flow-calmed zone ( 8th ) is arranged. Device according to one of claims 1 to 13, characterized in that between two combinations of blowing and suction chamber ( 1 . 2 ) a separation device for the temporary separation of the flowed cooling chamber areas ( 4 ) is arranged to adjust the ratios of supplied and discharged gas flow. Device according to one of claims 1 to 14, characterized in that the gas discharge ( 20 ) with the gas supply ( 10 ) is connected for re-feeding into the blow chamber optionally with the interposition of a cleaning device for cleaning the discharged gas and admixture of fresh gas. Device according to one of claims 1 to 15, characterized that fed into the blow chamber Gas atmospheric Air, water vapor, inert gas or a mixture thereof. Device according to one of claims 1 to 16 for spinning polyurethane raw materials with a dryer ( 40 ) for receiving the raw materials, an extruder ( 41 ) for transferring the raw materials into a melt and a mixing device ( 43 ) for admixing an isocyanate group-containing prepolymer, the melt thus mixed with the at least one spinning head ( 3 ) can be fed. Apparatus according to claim 17, characterized in that the prepolymer via a metering pump ( 46 ) is immiscible. Apparatus according to claim 17 or claim 18, characterized in that for the admixture of the prepolymer, a ring line ( 47 ) with a storage container ( 44 ), a booster pump ( 45 ) and a resistive element ( 48 ), one ( 46 ) or several dosing pumps to the loop ( 47 ) behind the booster pump ( 45 ) are connected.