EP1902164B1 - Spinning apparatus and process for producing fine threads by splicing for forming a nonwoven, and nonwoven obtainable thereby - Google Patents

Abstract

A spinning apparatus for producing fine threads by splicing, which comprises a plurality of protruding spinneret jets disposed in a spinneret jet portion and having spinning orifices from which the spinning dopes exit as monofils and having a plurality of acceleration jets, in particular Laval jets, whose cross section reduces, only to widen downstream of the smallest cross section, which are assigned to the spinning orifices is proposed to be provided with means for feeding gas streams which surround the monofils and are accelerated by the acceleration jets. The acceleration jet, in an at least partially plate-shaped gas jet portion, is constructed as a funnel-shaped depression into which the spinneret jet reaches to form gas flow channels. Means for relative displacement of the gas jet part and of the spinneret jet part relative to one another are provided such that the flow cross section of the gas flow channels is alterable and/or the position of the smallest cross section of the acceleration jets is adjustable in relation to the spinning orifices.

Description

The invention relates to a spinning device for producing fine threads by splicing according to the preamble of the main claim.

Fine threads down to less than 1 micrometer (μm) can be made by splicing a filamentary fluid stream as a melt, solution, or, generally, as liquids which are later solidified, as in US Pat DE 199 29 709 and DE 100 65 859 has been described. The mechanism of the thread formation is fundamentally different than in all hitherto known spinning process, where the dope is withdrawn by winders from the spinnerets to threads or in the spunbonding process by accompanying air currents that exert a force on them and in particular execution in so-called meltblown process, where the air pulling the thread emerges close to the spinneret orifices heated to about textile fiber temperature. The yarn speed reaches that of the winding or is under the pulling air or gas streams. This applies to the mean of the thread diameter, individual 'outliers' are discovered in the meltblown process, where even finer than the throughput and maximum possible withdrawal speed, the largest air velocity, diameter can adjust, but not in a targeted manner as it the said new method, also referred to as Nanoval method happens. Here is a new mechanism, recently explained in the basic hydrodynamic laws, see Gerking in Chemical Fibers International 54 (2004) pp. 261-262 and 56 (2006), pp. 57-59 If a melt or generally fluid filament or film is acted upon externally by shear stresses, pressure builds up in its interior when the velocity on the outer surface of the fluid jet is greater than that in its interior and this more so. the greater its acceleration can be achieved after exiting the spinning orifice. This is, so to speak, the reversal of the flow in pipes or channels (Hagen-Poiseuille), where the pressure energy is used to overcome the friction on the channel walls, while in the case of the new spinning process energy is applied to the thread through the outside him acting shear stresses is transmitted. He tries to resist this by pressure increase inside. Cooling not only the outer skin by the surrounding gas flow, it can lead to the solidification of the thread.

In the case of polymers and polymeric solutions with their In principle, only low thermal conductivity forms an outer skin of increasing viscosity and inside the thread, the hydrodynamic effects can act. It comes then in beautiful regularity and reproducibility to a bursting comparable to the bursting of a pipe at its longitudinal seam with in an astonishingly substantially endless threads and based on the stochastic character of the splicing low dispersion width in the thread diameter. The number of individual threads thus produced exceeds in the production of very fine threads in the range of and below 1 micron up to several hundred from a liquid jet.

The nanoval process is performed in line nozzles in its industrial applications, with a series of spin holes located above a gap. The gas, generally air without special conditioning after its generation in blowers or compressors (the energy requirement is generally low compared to the meltblown process) flows on both sides of the row nozzle in steady acceleration to the narrowest cross-section of the gap, which then again usually expanded rapidly, but basically has the configuration of a Laval nozzle. Single round nozzles were described as well, surrounded by a continuously decreasing annular gap.

It has been shown that the thrust forces acting on all sides by a rotationally symmetrical gas flow lead to a smaller average diameter of the substantially endless threads resulting from the splicing, which is attributed to the more uniform loading of the thread whether or not the air is heated additionally. The cooling, which causes the Aufplatzeffekt with the hydrodynamic forces in the interplay is more evenly distributed around the thread than happens in the only lateral admission in line nozzles with linear Laval nozzle configuration and it is less air consumed. In the row nozzles, part of the air is used less well in the spaces between thread to thread.

Another influencing factor for the production of fine and ever finer threads, which can otherwise be produced for example only by electrospinning, but in very low throughputs and large space and security costs because of the required high voltage, is the throughput per spinneret opening, whether with round or slit-shaped openings for the textile material. The gas velocity can reach the speed of sound in the narrowest cross-section of the Laval nozzle, and behind it, in the extension, it is quite possible to go into the supersonic, which then, in the case of this flow laden with filaments, usually quickly leads to subsonic effects due to compaction shocks. But it can only be done a certain deformation work by the shear stress forces at a given tread of the still deformable yarn mass. The throughputs are therefore generally smaller in the production of very fine threads in the range of and below 1 micron. This results in the need for more spinnerets across the width for a particular overall throughput in the production of nonwovens by the nanoval process for finer filaments. In the production of yarns that applies accordingly.

The invention has for its object to provide a device for producing fine threads, the compact and structurally simple, with a good piecing should be possible.

This object is achieved by the characterizing features of the main claim in conjunction with the features of the preamble.

The features illustrated in the dependent claims advantageous refinements and improvements are possible.

Characterized in that the device for producing fine threads at least one spinning nozzle equipped spinning spinneret and an at least partially plate-shaped gas nozzle part having at least one gas supply space, said at least partially plate-shaped gas nozzle portion having a plurality of funnel-shaped depressions as acceleration nozzles, in which engage the spinnerets, such that combinations of spinnerets / acceleration nozzles, in particular Laval nozzles are formed with rotationally symmetrical gas flow channels, the device can be constructed compact with a variety of close-fitting combinations, the gas nozzle part and Spinndüsenteil be displaced relative to each other, so that between the gas nozzle part and spinnerets of Spinndüsenteils formed gas flow channels can take different flow cross sections, whereby the height of the spinning orifices to the narrowest cross section of the acceler Higungsdüsen, Laval nozzles in particular, is adjustable. As a result, the piecing is facilitated and at several nozzles next to and behind one another in the first possible by the gas nozzle part relative to the spinneret part is retracted towards the latter, so as not to affect the coming yarn path. The displaceability also facilitates the maintenance and cleaning of the spinnerets.

A particularly simple design is given when formed between the bottom of the spinning nozzle part from which project the spinnerets or spinning nipple, and the top of the plate-shaped portion of the gas nozzle portion of the gas space through which the gas, usually air, the accelerating nozzles is supplied.

It is particularly advantageous to provide a self-adjusting seal between spinneret and gas nozzle part to provide when introducing the gas nozzle part, which is compressed upon introduction of the gas during spinning by the then resulting pressure.

An advantageous embodiment, but somewhat more expensive and especially in the supply of "cold" air is to form the gas nozzle part as a hollow body, which is penetrated by the depressions and the cavity between the depressions forms the gas space, wherein the hollow body directed to the spinneret part openings , preferably rotationally symmetrical around the depressions around, over which the air or the gas passes to the accelerating nozzles.

It can be arranged side by side a plurality of nozzle and gas nozzle parts, wherein also different textile materials can be spun out.

Advantageously, below the plate-shaped region of the gas nozzle part, a further plate be arranged with openings to form a distribution space for another fluid. This fluid may be water for coagulating dissolved pulps, coolant for freezing the molecular orientation achieved in the splice, means for heating, eg, water vapor, for a second draw, or the like.

Fig. 1

einen Längsschnitt durch ein erstes Aus- führungsbeispiel der erfindungsgemäßen Spinnvorrichtung entsprechend den Schnitt- linien D-D nach Fig. 2,

Fig. 2

einen Schnitt der erfindungsgemäßen Vor- richtung entsprechend den Schnittlinien C- C aus Fig. 1,

Fig. 3

einen Schnitt durch einen Teil der erfin- dungsgemäßen Vorrichtung nach einem zwei- ten Ausführungsbeispiel entsprechend der Schnittlinie A-A in Fig. 4, und

Fig. 4

einen Schnitt durch die Vorrichtung ent- sprechend der Schnittlinie B-B in Fig. 3.

The invention is illustrated in the drawing and will be explained in more detail in the following description. Show it:

Fig. 1

a longitudinal section through a first exemplary embodiment of the spinning device according to the invention according to the cutting lines DD after Fig. 2 .

Fig. 2

a section of the device according to the invention according to the section lines C-C Fig. 1 .

Fig. 3

a section through a part of the inventive device according to a second embodiment according to the section line AA in Fig. 4 , and

Fig. 4

a section through the device corresponding to the section line BB in Fig. 3 ,

In the Fig. 1 and 2 The spinning device shown has a spinneret part 28 in which a plurality of melt channels 14 are provided, which are supplied via a filter 25 and a perforated plate 26 for cleaning supplied melt or solution with melt or solution. The melt channels continue in spinnerets or spin nipples 23, wherein only three rows of nipples 23 are shown here. It may well be several consecutive spider nipples in the direction of travel arrow 50 provided.

The lower plate-shaped region of the spinneret part is accommodated in a gas nozzle part 27, which comprises a frame-like border 34 and a plate-like part 35, in the latter three staggered rows of Laval nozzles 36 corresponding to the rows of spin nipples 23 are provided. The border 34 is provided with an upstand, wherein a seal 33 is arranged between this upstand and an opposite surface 32 of the lower region of the spinneret part 28.

The spinning and the gas nozzle parts 28, 27 are aligned with each other so that the tip of the spinning nipple 23 project into the Laval nozzles 36, wherein between the lower surface of the spinneret member 28 and the upper surface of the plate-shaped portion 35 of the gas nozzle part, a gas space 22 is formed, through which the spinning nipple 23 extend and which is connected to the gas or air feeds 20 provided in the border.

In particular, when the supplied air is cold, the spinning nipples 23 are preferably provided with a heater 24, advantageously with a band heater, as is known from injection molding tools in plastics engineering.

The device according to the invention has means for relative displacement of the spinning and gas nozzle part 28, 27, wherein in the present embodiment, a screw 29 fixed in one with the spinneret part connected nut lock 30 is guided and connected in an anchorage 31 in the frame 34 of the gas nozzle part 27 with this, the anchorage 31 can exert pressure or pulling action according to the direction of rotation of the screw 29, whereby the gas nozzle part is moved. Of course, other types of shifting means are possible.

For piecing, the gas nozzle part 27 is raised, ie in the Fig. 1 shifted upward, whereby the seal 33 is relieved. If, after starting, the gas 21 is supplied via the supply 20, in addition to a displacement of the gas nozzle part 27 down a compressive force on the seal 33 by the pressure in the gas space 22 is amplified. There is thus a certain self-adjustment of the seal when starting the melt or solution and release of the Laval nozzle cross-section to the individual spinning nipples.

For cleaning the spinning nipple 25, the gas supply 21 is turned off, the gas nozzle part 27 is raised until the plate member 35 abuts the wall of the Laval nozzles 35 on the spinning nipples 25. The existing air in the region of the seal 33 and the surface 32 is blown out. The nipples 25 protrude out of the laval nozzles and can be cleaned.

In the Fig. 3 The device shown has a spinneret part 1 with a series of elevations or projections, preferably in the form of cones, which receive or form spinnerets 13. For example, the spinning nozzle part may be formed as a plate into which the spinnerets 13 (similar Fig. 1 ) are used. The spinnerets have melt or dissolution channels 14 which terminate in a spinneret orifice 3. Furthermore, a gas nozzle part 2 is provided, which is formed for example as a hollow body which is formed by two plates provided with funnel-shaped depressions.

Between the plates, a cavity 9 is formed, which is interrupted by the funnel-shaped depressions. The cavity 9 serves as a gas space, which in turn is connected to a gas supply source. Around each funnel-shaped depression around an annular opening 4 is incorporated, wherein the in Fig. 3 shown in section openings 4 accordingly Fig. 4 jointly apply to adjacent funnel-shaped depressions, ie in the embodiment, the funnel-shaped depressions are arranged close to each other.

The conical, the spinnerets 13 forming elevations engage in the depressions of the gas nozzle part 2 such that rotationally symmetrical gas flow channels 5 arise. In the illustrated embodiment, in each case in the intermediate space between the spinnerets 13, which in Fig. 3 are shown as depressions, with the formation of an air gap 12 is still an insulating mold 11 inserted, which extends to the spinning opening 3, so.dass the gas flow channel 5 between the surface molding 11 and surface of the recess in part 2 is formed around the space 9. In this case, the respective gas flow channel 5 is formed so that it tapers in the direction of the respective spinning opening 3, which is surrounded rotationally symmetrically by the respective depression. It is thus realized in each case a Laval nozzle whose cross-section at the edge between the recess and outer surface of the in the Fig. 3 bottom plate suddenly expanded, but also gradually can happen.

The spinneret part 1 and the gas nozzle part 2 are relative to each other, respectively Fig. 3 seen, displaced in the vertical direction, which can be realized by sliding rods, not shown. Thereby, the height of the narrowest point 6 of the Laval nozzle with respect to the spinning opening 3 can be adjusted, whereby the piecing is facilitated.

These slide bars can simultaneously absorb force arising at different expansions of the spinneret 1 and the gas nozzle part 2, whereby the positioning of both parts is maintained.

In Fig. 4 are two rows of combinations of spinneret 13 and Laval nozzles, ending in the narrowest cross-section 6 shown, the spinnerets 13 are offset one row to those of the other rows. It is possible in particular for larger spinning beam widths that separate gas distribution channels are provided between adjacent rows in order to introduce the required quantities of gas to the Laval nozzles.

In the following the functionality is discussed.

In Fig. 3 the melt is brought in the part 1 and exits in the spinneret orifices 3, while the gas, hereinafter referred to as air, from the space 9 in the part 2 after exiting through the annular opening 4 to the spin orifice 3 rotationally symmetrical channel 5 between part 1 and 2 flows to the narrowest cross section 6 and previously detected at the spinning opening 3, the emerging thread 7, it accelerates, ie reduced in diameter and after the nanoval effect already in the Laval nozzle or shortly thereafter for brush-like bursting into a bundle of threads 8 brings.

While the piecing in a line nozzle is done simply by pushing together two halves of the channel forming the Laval nozzles, this is not possible with nozzle combinations in several rows. The part 2 can be moved in the direction of the thread exit axis. As a result, it can be completely withdrawn during piecing to the molded part 11, a blow-out of spinning air through the openings 4 can initially be omitted or it is allowed to a small extent. Then the part 2 is lowered, the thread spun, warped and burst according to the known from the process air speed adjustment data from the applied pressure in the space 9 of Part 2, for the flowing dope from the openings 3 and in the for the Splicing required temperature of the dope. This is advantageously only shortly before exiting from the spinning holes 3 additionally heated, indicated by heaters 10, was dispensed with their introduction and support the clarity of the drawing. So that the flowing air at temperatures lower than the spinning mass temperature does not unduly cool it, the molded part 11 is designed such that it forms the inner wall of the rotationally symmetrical channel 5 for a steady acceleration of the air close to the spinneret orifice 3, but over an air gap 12 and the spinneret 13 against the air flow in the flow channel 5 thermally insulated. However, the molded part 11 can also contain the heaters of the spinnerets instead of the spinneret part 1.

The two basic positions of the movable part 2 are in Fig. 3 indicated, dashed for piecing.

Fig. 4 shows a horizontal section BB (in Fig. 3 ) as a section through a multi-row nozzle device for two rows of nozzles to illustrate the air supply from the outside to the individual spinnerets 13 for feeding from the space 9 via the openings 4 in the channels 5, each of which ends at the smallest cross section 6.

It can be installed with larger air requirements, so with larger fleece and thus spider bar widths, main distribution channels between the nozzle openings, with only the rows of individual nozzles in fleece running slightly apart, because the spinnerette device according to the invention has the same advantage as a spinning beam, that he seen in web travel direction forms several spinning beams in a row. Each has its own unevenness, even from hole to hole as in the case shown here with spinneret and Laval nozzle across the fleece width. Between the individual rows a statistical compensation for greater fleece uniformity can take place, because the threads of the following rows increasingly occupy the thin areas of the preceding ones.

If gas or air or a liquid medium for accompanying it is also desired for cooling or keeping warm, for spinning solutions and for coagulating the threads, this medium can be easily introduced as a third fluid flow between the spinning and laval nozzles and brought to the outflow. This is in Fig. 1 illustrated by a plate 37, with openings 38 each below the spinning nipple 23 and the Laval nozzle-like openings 36 is provided. Similar to the supply of air into the space 22, the third fluid flow can be introduced into the space 41 formed between the plates 35 and 37 at 39 according to arrow 40. He steps from there over the upper edges of the openings 38 in the thread air flow. This can be done, for example, to initiate the coagulation of pulp from Lyocelllösungsfäden, as in the DE 100 65 859 described in more detail. The size of the openings 38 and their location to the spin nipples 23 can be easily matched to the main flow of the thread with the surrounding gas. All three fluids flow down (in the drawing).

The device is also fundamentally suitable for spinning out different textile materials in the individual spinnerets, for which purpose the melt or dope distribution must be set up accordingly, be it alternately transversely to the direction of travel or else different from row to row. It is thus possible to produce mixed nonwovens to achieve special effects such as the binding of binding threads in matrix threads, eg polypropylene as binder thread and polyester as the strength-giving matrix or by a part of more shrinking threads to after fleece storage by shrinkage of the entire thread structure higher volume and softness and other nonwoven properties by two or more different components. Bi- or multicomponent filaments can also be produced easily by feeding two or more textile materials into the spinneret part and into the channels 14. Different throughputs, set by differently sized opening cross sections of the spinneret openings or controlled melt supply to these, can be another type of Mixed fleeces are produced.

The present device also has the advantage that it connects the melt-carrying spinneret parts 1 and 28 with the colder gas nozzle parts 2 and 27 against each other displaceable, but transversely to firmly. After heating of Part 1 with heaters not shown here, in principle, if no particularly heated air from Part 2 is supplied, Part 1 to 2 expand more so that each spin hole 3 and closest cross-section 6 deviations across the width and length, the The same applies to the parts 28 and 27. The connection can be made by the slide rods, not shown, which prevent this deviation in terms of power, wherein they can be arranged in the plates of the spinneret part 1 and the gas nozzle part between the combinations spinneret / Laval nozzle. In order to prevent the different expansion but also aware of a warming of the air flow in the flow channel 5 can be made.

A guide of the part 1, which is initially set back relative to the spinning bore opening 3 and later displaced in the direction of the thread 7 to produce the splicing effect, has to be done by known in tool making guides or slide rods. The introduction of the air, also not drawn here, happens from the outside from the front, back or side of the spinning beam, with a seal between spinneret 1 and gas nozzle part 2 must be present or because a few millimeters of guide length between 1 and 2 sufficient, also Wellbälge to the Spinning bars around and an outer distribution chamber can be found in Fig. 4 shown chambers 9 are fed.

It is now also possible in a simple manner to divide spinning beam of greater width into several nozzle fields, these in turn consisting of numerous individual spinneret / Laval nozzle combinations, so that individual of these packages (spin packs) can be replaced in case of blockages of the spinning openings or other disorders. The parting lines are then mounted obliquely to the direction of rotation, wherein the spinneret openings as in Fig. 4 shown are each arranged on the gap of the previous.

The following example shows the use of the device in the splicing spinning process according to Nanoval and the yarn values obtained by way of example. A polypropylene melt was distributed to nineteen in-line spinnerets 13 with melt inlet holes 14 and spinneret holes 0.3 mm in diameter. In the thread running direction thereafter, there was a Laval nozzle with the narrowest cross section of 3 mm diameter, which was returned to the spinning opening after piecing to each of these openings. The polymer flow rate was changed in areas as shown in Table 1, as well as the air pressure and thus the flowing air velocity in the area of the thread for the splicing shear stresses. The temperature of the polypropylene melt could be heated in the spinneret 13 by about another 20 ° C shortly before it exits the spinning orifice via electrical heating elements.

For a device according to the FIGS. 1, 2 result in the same process data not significantly different results. <b> Table 1 Thread Results Polypropylene (PP) MFI 28 Melt Index at 230 ° C and 2.16 kg </ b> melt air thread result m ₀ T _s ΔP _k T _L d ₅₀ CV d _min d _max g / min ° C mbar ° C microns % microns microns 1.5 330 403 43 3.9 38 1.72 8.2 330 600 47 2.2 23 1.22 3.6 330 800 56 2.2 45 0.87 4.4 334 400 230 1.5 47 0.87 3.5 335 600 230 2.0 40 0.67 3.8 336 0.78 800 233 1.5 40 3.1 3.0 344 400 230 2.4 33 0.61 3.9 344 600 230 2.1 33 1.12 3.4 344 800 230 1.5 47 0.44 3.4 352 400 46 2.1 48 0.77 4.9 352 600 46 1.2 42 0.31 2.2 352 800 46 1.3 31 0.48 2.3 351 600 180 1.2 33 0.63 2.3 351 600 220 1.0 40 0.44 1.8 351 600 220 1.1 27 0.49 1.8
m _o polymer throughput per spin hole
T _s melt temperature
ΔP _k Air pressure before acceleration in the Laval nozzle
T _L air temperature at the same location
d ₅₀ avg. Thread diameter from 20 individual measurements on the microscope screen
CV statist. Scattering / d ₅₀ 100% coefficient of variation the generated thread diameter
d _min smallest each measured thread diameter

It is striking that not only at higher air pressures, ie higher air velocities, higher air temperatures and lower throughputs, the fine filaments could be produced down to about 0.5 μm = 500 nanometers (nm), but also at larger throughputs of 3 g / min and hole was achieved by raising the temperature of the melt from 335 to 352 ° C prior to its discharge, however, the air temperature initially remained at the higher throughput of 3.0 g / min in the area produced by the compression and the Increase with otherwise constant values to 180 ° C no measurable influence towards higher fineness resulted. Only an air temperature increased to 220 ° C then gave the value of d ₅₀ = 1 micron with measured in the microscope minimum diameters of 0.44. However, a thread measurement as here with the microscope can no longer claim high accuracy, since one is already in the range of light wavelengths. In any case, there are clear dependencies that are initially surprising from the standpoint of conventional spinning. However, if one realizes that threads are produced by bursting, that is fragmentation, then other laws than those of pure longitudinal distortion as described above are at work, which lead to the fact that one can change individual parameters such as the melt temperature to the gas velocity same influence on the resulting average thread diameter and even their dispersion.

Although the device according to the invention is primarily intended for the production of fine threads, can also coarser are spun with her, showing her versatility. Thus, threads of polyester and polylactide were produced as shown in Tables 2 and 3. The diameter of the spinneret orifices was 1.0 mm. <b> Table 2 Thread Results Polyester (PET) iv = 0.64 Intrinsic Viscosity (Textile Type) </ b> m _o T _s ΔP _k T _L d ₅₀ CV d _min d _max g / min ° C mbar ° C microns % microns microns 5.2 288 550 108 10.1 47 4.1 20.0 332 1000 271 4.2 43 1.5 9.9 10.0 299 500 270 15.3 23 7.4 19.8 271 1000 106 19.0 35 8.0 26.9 15.0 325 500 167 23.2 25 9.8 36.6 330 1000 165 11.3 65 4.2 33.2

When spinning polyester threads it proved to be an advantage to pull the threads after their bursting through an injector channel a good 1 meter deeper as in L. Gerking, change of the filament properties of the polymer and in the Spinning line, manmade fibers / textile industry 43/95 (1993) on pages 874/875 described. By heating up again in between as in DE 19 65 054 Column 4, lines 44 to 57, could be increased with both measures, the tensile strength of the threads, but especially the shrinkage can be significantly reduced.

The polymer polylactide prepared from natural raw materials showed the values reproduced in Table 3 in splice spinning to coarser threads. <b> Table 3 Thread Results Polylactide (PLA) MF (melt flow index) 22 at 210 ° C and 2.16 kg </ b> m _o T _s ΔP _k T _L d ₅₀ CV d _min d _max g / min ° C mbar ° C microns % microns microns 5.2 253 352 35 26.6 19 13.5 33.9 254 352 35 14.4 37 4.4 27.7 254 780 44 16.4 56 5.0 48.3 7.6 284 507 52 6.5 43 2.0 11.1 9.0 255 807 56 14.2 46 5.0 28.7 254 831 60 40.5 (1) 18 26.8 50.1 245 348 60 14.4 75 3.9 44.3 9.7 277 889 64 9.9 59 3.7 29.3 10.1 253 915 90 24.1 (2) 45 5.4 42.8 13.3 285 185 47 7.8 40 1.22 15.0

In Table 3, the value marked with (1) falls out of the otherwise recognizable dependencies, also as the largest value. In this setting, the aerodynamic conditions were changed by changing the Lavaldüsengeometrie, also at the value marked with (2). In (1) no splicing of the melt filament occurred at (2) now and then.

The device according to the invention can be used for thread-forming melts or solutions, but also generally for liquids, for example when it comes to applying thin layers such as paints, varnishes, coatings. It then serves to atomize the liquids into the finest possible droplets if possible uniform distribution on the area to be assigned. The conditions are easy to find in each case by the given geometric adjustment of the device.

The devices (according to Fig. 1, 2 or 3, 4 ) have the further advantage that a melt or solution can be distributed more easily uniformly to individual outflow openings - in this case nipples 23 - than when this happens from a film, as is usually the case with row nozzles. The fleece produced has more uniform and usually not especially the webs, also called "lanes" strips of different weight in the direction of travel.

Claims (18)

1. Spinning device for producing fine threads by splitting, having a plurality of protruding spinning nozzles (13, 23) with spinning openings which are disposed in a spinning nozzle part (1, 28) and from which the spinning materials emerge as monofilaments and having a plurality of acceleration nozzles (36), in particular Laval nozzles, which are assigned to the spinning openings and the cross-section of which is reduced and widens after the smallest cross-section, means being provided for supplying gas flows, which surround the monofilaments and are accelerated through the acceleration nozzles, characterised in that
   the acceleration nozzle is configured in an at least partially plate-shaped gas nozzle part (2, 27) as a funnel-shaped depression into which the spinning nozzle engages forming gas flow channels and in that means for relative displacement of the gas nozzle part (2, 27) and of the spinning nozzle part (1, 28) relative to each other are provided such that the flow cross-section of the gas flow channels can be changed and/or the position of the smallest cross-section of the acceleration nozzles can be adjusted relative to the spinning openings.
2. Spinning device according to claim 1, characterised in that the means for relative displacement comprise guides and/or sliding rods.
3. Spinning device according to claim 1 or claim 2, characterised in that the means for relative displacement is configured as adjustment screw device (29, 30, 31) which is disposed between gas nozzle part (2, 27) and spinning nozzle part (1, 28).
4. Spinning device according to one of the claims 1 to 3, characterised in that a gas chamber with at least one gas supply is provided between spinning nozzle part (1, 28) and gas nozzle part (2, 27), said gas chamber being in communication with the gas flow channels and into which the spinning nozzles (13, 23) protrude.
5. Spinning device according to one of the claims 1 to 4, characterised in that the gas nozzle part (27) is provided with a frame-like edging (34), the region of the spinning nozzle part (28) which has the protruding spinning nozzles (23) being inserted between the edging.
6. Spinning device according to one of the claims 1 to 5, characterised in that a self-adjusting seal is provided between spinning nozzle part (28) and gas nozzle part (27).
7. Spinning device according to one of the claims 1 to 4, characterised in that the gas nozzle part (2) is configured as a hollow body which is engaged by the funnel-shaped depressions, the space within the hollow body (5) forming a gas chamber and openings (4) directed towards the spinning part (1) being provided, which connects the gas chamber to the gas flow channels.
8. Spinning device according to claim 7, characterised in that formed parts are respectively inserted between the spinning nozzle of the spinning part maintaining air gaps relative to the gas nozzle part for heat insulation, which gaps extend essentially up to the spinning openings, the gas flow channels (5) being formed between the formed parts (11) and the gas nozzle part (2).
9. Spinning device according to one of claims 7 or 8, characterised in that the openings (4) are disposed annularly around the funnel-shaped depressions.
10. Spinning device according to one of the claims 1 to 9, characterised in that the gas chamber is sealed externally.
11. Spinning device according to one of the claims 1 to 10, characterised in that the gas nozzle part (2, 27) and the spinning nozzle part (1, 28) have a plurality of funnel-shaped depressions and spinning nozzles which are disposed in rows adjacent to each other, the spinning nozzles (13, 23) and acceleration nozzles of the one row being disposed offset relative to the other row.
12. Spinning device according to one of the claims 1 to 11, characterised in that the combination of gas nozzle- and spinning nozzle part comprises a plurality of gas- and nozzle part segments which are exchangeable, respectively.
13. Spinning device according to one of the claims 1 to 12, characterised in that several gas- and spinning nozzles are arranged with spacing adjacent to each other.
14. Spinning device according to one of the claims 1 to 13, characterised in that a distribution device (37, 38) for an additional fluid is provided on the gas nozzle part at a spacing from the exit of the acceleration nozzles, which fluid impinges upon the threads which have split from the monofilament.
15. Method for producing a spunlaid nonwoven of fine threads from melts or solutions by splitting a plurality of monofilaments which are spun by spinning nozzles (13, 23) disposed in a spinning nozzle part (1, 28) and protruding therefrom, wherein the melt or solution is uniformly distributed over the spinning nozzles and the monofilaments respectively are accelerated until splitting by a rotation-symmetrical gas flow produced by rotation-symmetrical acceleration nozzles (36, 5) and
    wherein the spinning nozzles are disposed in a plurality of successive rows in the nonwoven running direction such that a statistical compensation is effected by covering the sparse positions of the nonwoven produced by the threads of the preceding rows by means of the threads of the following rows.
16. Method for producing a spunlaid nonwoven of fine threads according to claim 15 using a spinning device according to claim 14, characterised in that an additional fluid is introduced into the space between the gas nozzle part (27) and the plate (37) with openings (38) which is arranged with a spacing to the gas nozzle part, respectively below the spinning nipples of the spinning nozzles (23) and the rotation-symmetrical laval nozzle-like openings (36), the additional fluid penetrating the thread gas flow via the edges of the openings (38) of the plate (37) and meeting the threads splitted from the monofilaments.
17. Method according to claim 16, characterised in that water for coagulating for the production of threads from a lyocell solution or a coolant for freezing the molecular orientation obtained while splitting or a heating medium for realizing a second drawing of the threads is introduced into the space.
18. Spunlaid nonwovens produced by a spinning method according to one of claims 15 to 17.

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