EP3239378B1 - Device and method for the manufacture of material from continuous filaments - Google Patents

Description

The invention relates to a device for the production of nonwovens from continuous filaments, the filaments consist in particular of thermoplastic material, wherein at least one spinning device for spinning the filaments is present, wherein the filaments are cooled and stretched and wherein a storage device is provided for storing the drawn filaments , The invention further relates to a process for the production of nonwovens from continuous filaments. - Endless filaments differ because of their quasi-endless length of staple fibers, which have much smaller lengths, for example, 10 mm to 60 mm.

Devices and methods for producing nonwovens of the type mentioned are known in various embodiments from the practice and from the prior art. The WO 03/038168 A1 describes in this context a woven screen belt for the storage of spunbonded webs, which consists of warp and weft threads and influenced by its special structure, the flow of air through the storage belt such that a uniform spunbond results and at the same time a low fiber breakdown is achieved.

It is also often desirable to produce structured "spun" nonwovens having a "3D" structure with varying local thicknesses or porosities. Also, various measures are known from practice and from the prior art. So it is already known to produce a corresponding nonwoven structure by embossing or mechanical deformation of the web. The deformability of the nonwovens can be achieved in the rule only by preheating the nonwoven web to the softening of the plastic. The deformation then has a compaction for As a result, the nonwoven web becomes flatter overall and this impairs the desired soft feel of the nonwoven web.

Furthermore, it is known, in particular for short fibers or staple fibers, to relocate the short fiber deposit, for example by compressed air, and then to carry out a hot air hardening. However, this limits the choice of material for the nonwoven web, since fibers from many polymers can not easily be hot-air-hardened. For continuous filaments, these measures have not proven otherwise.

Another method is based on the use of a structured and partially air-permeable storage belt ( EP 0 696 333 ). The storage belt is equipped with air-impermeable closing points and these closing points have protruding projections from the wire belt surface. The deposited filaments are preconsolidated on the storage belt with an adhesive - hot air-solidified, for example - and then the nonwoven fabric is peeled off. The structure of the web is achieved, as it were, by taking an impression of the locking point protrusions projecting from the depositing belt surface. Similarly describes WO 2004/061219 A1 a storage belt which is partially closed by application of a polymer material. The pattern thus produced on the tape can be transferred to products which are deposited on the tape. Also US 4,514,345 A relates to a deposit screen belt to which a shape excellent from the screen belt surface is applied so that a paper web deposited on the belt is patterned according to the shape. However, these known measures are often prone to interference and error and have not been proven in practice.

In contrast, the invention is the technical problem of providing a device of the type mentioned, with a non-woven with 3D structure can be produced in a simple and efficient manner, this fleece is characterized by an aesthetically flawless, reproducible 3D structure and also has a sufficiently soft grip. The invention is further based on the technical problem of specifying a corresponding method for producing the nonwoven and a corresponding nonwoven.

To solve this technical problem, the invention teaches an apparatus for producing continuous filament nonwovens, wherein the filaments consist in particular of thermoplastic material, wherein at least one spinning device for spinning the filaments is present, wherein the filaments are cooled and stretched and wherein a storage device is provided for depositing the drawn filaments to the nonwoven fabric,
wherein the storage device is designed in the form of a sieve belt having a plurality of screen belt openings distributed over the screen belt surface, whereby air can be sucked through the screen belt surface or through the screen belt openings and for this purpose at least one suction fan is arranged below the screen belt, whereby a part of the screen belt openings is closed is trained.

According to a particularly preferred embodiment of the invention, the device according to the invention is a spunbond apparatus, wherein a cooling device is provided for cooling the filaments and a stretching device for drawing the filaments. Another embodiment The invention is characterized in that the device according to the invention is a meltblown device.

According to the invention, the air permeability of the unclosed screen belt is 300 to 1100 cfm (510 to 1870 m ³ / h), preferably 350 to 1050 cfm (595 to 1785 m ³ / h) and preferably 400 to 1000 cfm (680 to 1700 m ³ / h) and the air permeability of the partially closed screen belt according to the invention is 150 to 700 cfm (255 to 1190 m ³ / h), preferably 200 to 600 cfm (340 to 1020 m ³ / h) and preferably 250 to 500 cfm (425 to 850 m ³ / h). H). The air permeability of the partially closed screen belt is particularly preferably 300 to 500 cfm (510 to 850 m ³ / h) and very particularly preferably 350 to 500 cfm (595 to 850 m ³ / h). In the context of the invention, the uncovered screen belt means the screen belt used according to the invention with only open or unclosed screen belt openings. In that regard, the unclosed screen belt serves only as a reference, since according to the invention a partially closed screen belt or a screen belt is used with partially closed Siebbandöffnungen. - It is understood that the air permeability of the unclosed screen belt is greater than the air permeability of the partially closed screen belt.

The air permeability is given here in cfm (cubic foot / min). The measurement of the air permeability is preferably carried out on a circular area of 38.3 cm ² at a pressure difference of 125 Pa. Conveniently, a plurality of individual measurements is carried out - recommended ten individual measurements - and the air permeability results then by averaging the individual measurements. It is within the scope of the invention that the air permeability is measured according to ASTM D 737. It is furthermore within the scope of the invention for the screen belt to intersect a woven fabric Has threads. Conveniently, the threads of the screen belt as plastic threads - in particular as monofilaments - and / or formed as metal threads. In this case round and / or non-round cross-section threads can be used in cross-section. The fabric of the wire can be single-layered or multi-layered. In the case of a multilayered fabric, the surface of the uppermost layer of the fabric is understood here to mean the surface of the sieve belt. According to a preferred embodiment, the screen belt has only one layer of a fabric.

A recommended embodiment of the device according to the invention is characterized in that the screen belt has a fabric of warp threads and weft threads delimiting the wire belt openings. It is recommended that the fabric of the screen belt has a weaving density of 20 to 75 warp threads / 25 mm and preferably from 30 to 55 warp threads / 25 mm and from 10 to 50 weft threads / 25 mm, preferably from 10 to 40 weft threads / 25 mm.

It is within the scope of the invention that a plurality or plurality of open Siebbandöffnungen is distributed over the Siebbandoberfläche and that also a plurality or a plurality of closed Siebbandöffnungen is distributed over the Siebbandoberfläche. A closed screen belt opening or several adjacent closed belt openings form a closure point of the screen belt. It is recommended that the diameter d or the smallest diameter d of a closure point of the screen belt is at least 1.5 mm, preferably at least 2 mm and not more than 8 mm, preferably not more than 9 mm and in particular not more than 10 mm. - Conveniently, the ratio of the air permeability of the unclosed screen belt to the air permeability of the partially closed screen belt amounts to 1.2 to 4, preferably to 1.3 to 3.5, preferably to 1.5 to 3 and particularly preferably to 1.8 to 2.8.

The closed Siebbandöffnungen or the closure sites require that the screen belt in contrast to the unclosed screen belt no longer has a homogeneous air permeability. Insofar, the invention is based on the finding that the closure points of the air flowing inwards onto the sieve belt impose a lateral movement directly above the sieve belt. The filaments to be deposited contained in this air flow follow this lateral air displacement at least partially and are thereby preferably deposited on the open or unclosed areas of the screen belt. In this way, a fleece with different local basis weights or with a defined 3D structure is created.

According to a particularly recommended embodiment of the invention, the closed Siebbandöffnungen or the closure sites are arranged distributed in a regular pattern on the wire. Empfohlenermaßen have the Siebbandöffnungen or the closure points in at least one spatial direction at constant distances from each other. According to a preferred embodiment of the invention, the closure points are punctiform. In particular, dot-shaped here means that the diameter is a closure point in all spatial directions similar or comparable or substantially the same. A proven embodiment is characterized in that the punctiform closure sites are distributed at regular intervals over the screen belt or over the screen belt surface. Conveniently, the smallest diameter d of these punctiform closure sites is at least 2 mm, preferably at least 2.5 mm and more preferably at least 3 mm and a maximum of 8 mm, preferably not more than 9 mm and very preferably not more than 10 mm.

According to a further preferred embodiment of the invention, the closure points are formed linear. It is within the scope of the invention that the linear closure points are usually not exactly rectilinear or linear and that, in general, especially the edges of the linear closure points are not formed exactly straight or linear. According to a proven embodiment, the linear closure points have constant distances or substantially constant distances from one another. Conveniently, the linear closure points are arranged parallel or substantially parallel to one another. It is also within the scope of the invention that the linear closure points are each formed as broken lines and are arranged on a line linear closure point sections and the sections connecting line-shaped open Siebbandbereiche. According to one embodiment of the invention, line-shaped closure points intersect, wherein preferably the linear closure points extending in one direction are arranged parallel to one another and wherein the linear closure points extending in a second direction are expediently (also) arranged parallel to one another. It is also within the scope of the invention that the line-shaped closure locations of a screen belt have different densities in different areas of the screen belt or the screen belt surface and / or have different widths (smallest diameters d). The linear closure points may also be curved or curved line-shaped closure sites. The width (smallest diameter d) of a linear closure point is preferably at least 1.5 mm, preferably at least 2 mm and recommended maximum 8 mm and in particular maximum 9 mm.

According to one embodiment of the invention point and line closure points can be combined. In principle, various geometric configurations for the closure points are conceivable and these different configurations can also be combined with each other. Open Siebbandbereiche may be surrounded by closure sites or by closed Siebbandbereichen or vice versa.

It is within the scope of the invention that sealing materials made of plastic or of polymers are used to produce the closed Siebbandöffnungen or for generating the closure sites. To produce the closure points, molten or liquid plastic is expediently introduced into the fabric of the wire belt or introduced into the wire belt openings of the wire belt. According to one embodiment, the sealing compound may be photosensitive plastic or a photosensitive multi-component system which is first introduced into the fabric of the screen belt and then cured and cured in particular under the action of light and preferably under the action of UV radiation. - It is within the scope of the invention that the sealing compound penetrates into the mesh openings of the mesh fabric and that the closure pattern formed depend on the weave and weaving density. Conveniently, the mesh fabric is formed from monofilaments having a diameter of 0.2 to 0.9 mm, preferably 0.3 to 0.7 mm. It is recommended that a closure site is formed by closing the screen belt openings between at least 2 warp threads and / or weft threads, preferably between / over at least 3 warp threads and / or weft threads.

A particularly recommended embodiment of the invention is characterized in that the sealing compound of the closure sites is arranged only in and / or below the screen belt surface and does not protrude beyond the screen belt surface. According to one embodiment variant, the sealing compound extends over the entire thickness or essentially over the entire thickness of the sieve belt or of the sieve belt fabric. According to another embodiment variant, the sealing compound of a closing point or of a closed sieve belt opening extends only over part of the thickness of the sieve belt fabric. Preferably, the sealing compound of a closed Siebbandöffnung or a closure point extends from the screen belt surface downwards, in which case the sealing compound - as described above - either over the entire thickness of the screen belt or only over a part of the thickness of the screen belt can extend. The sealing compound is expediently arranged over at least 30%, preferably over at least 33%, of the thickness of the sieve belt or of the sieve belt fabric, the closure mass preferably extending from the sieve belt surface downwards, as noted above.

According to a particularly recommended embodiment of the invention, at least 25%, preferably at least 30%, of the screen belt openings of the screen belt used in the invention are designed to be closed. Conveniently, a maximum of 67%, preferably not more than 60% of the Siebbandöffnungen the screen belt formed sealed.

According to the invention, the sealing compound of the closure sites is arranged in and / or below the sieve belt surface of the sieve belt and does not project beyond the sieve belt surface or protrudes by a maximum of 1.0 mm, preferably by a maximum of 0.8 mm, very preferably by a maximum of 0.6 mm and especially preferably at a maximum of 0.3 mm to 0.6 mm beyond the screen belt surface.

It has been explained above that the closure points cause a lateral air movement of the air flowing through the filter belt and that due to this lateral movement the filaments contained in the air flow follow the flow and are therefore preferably deposited on the open wire belt regions. The invention is based on the finding that this displacement can be effectively enhanced if the sealing compound of the closure points protrudes upward beyond the screen belt surface. Over the resulting dome, the deposited filaments can slip into the adjacent open Siebbandbereich and the differences in the filament density or in the basis weight can be characterized even more pronounced. The invention is further based on the knowledge that the height of the region projecting out of the sieve belt is limited, since a region which protrudes too high is associated with a reduction in the stability of the filament deposit. Finally, the invention is based on the finding that a region projecting out of the screen belt surface is preferably intended to protrude from the screen belt surface by a maximum of 0.6 mm, very preferably by a maximum of 0.5 mm.

The device according to the invention has at least one spinning device or spinnerette with which the endless filaments are spun. According to a particularly preferred embodiment of the invention spunbond nonwovens are produced with the device according to the invention and insofar is the Device designed as a spunbond device. Monocomponent filaments and / or multicomponent filaments or bicomponent filaments are produced as continuous filaments. The multicomponent filaments or bicomponent filaments can be continuous filaments with a core-shell configuration or endless filaments with crimped potential, for example with side-side configuration. According to a particularly preferred embodiment of the invention, the continuous filaments produced by the device according to the invention or by the process according to the invention consist of at least one polyolefin, in particular of polypropylene and / or polyethylene.

An apparatus according to the invention in the form of a spunbond apparatus has at least one cooling device for cooling the filaments and at least one drawing device for drawing the filaments.

According to a particularly recommended embodiment, which is of very particular importance in the context of the invention, the aggregate of the cooling device and the drafting device is designed as a closed aggregate, with the exception of the supply of cooling air in the cooling device no further air supply takes place in the closed unit. This closed embodiment of the device according to the invention has proven particularly useful in connection with the screen belt used in the invention.

A recommended embodiment of the invention is further characterized in that at least one diffuser is arranged between the drawing device and the depositing device or the screen belt. The continuous filaments emerging from the drawing device are passed through the diffuser and then deposited on the depositing device or on the screen belt.

A particular embodiment variant of the invention is characterized in that at least two diffusers, preferably two diffusers in the filament flow direction, are arranged one behind the other between the drawing device and the screen belt. Conveniently, at least one secondary air inlet gap for the entry of ambient air is provided between the two diffusers. The embodiment with the at least one diffuser or with the at least two diffusers and the secondary air inlet gap has proven particularly useful in combination with the screen belt according to the invention.

In the device according to the invention or in the context of the method according to the invention, air is sucked through the screen belt or sucked through the screen belt in the filament flow direction. For this purpose, at least one suction fan is expediently provided below the screen belt. Appropriately, at least two, preferably at least three, and preferably three separate suction regions are arranged one behind the other in the conveying direction of the wire. In the storage area of the endless filaments or fleece, a main suction area is preferably provided in which air is extracted with a higher suction speed than in the at least one further suction area or in the two further suction areas. Conveniently, in the main suction section, the air is drawn through the screen belt at a suction rate of 5 to 30 m / s. These are the average suction speed with respect to the wire belt area. A proven embodiment of the invention is characterized in that at least one further suction region is connected downstream of the main suction region in the conveying direction of the wire belt and that the suction speed of the air extracted in this further suction region is less than the suction speed in the suction line Main suction. It is recommended that a first suction region with respect to the conveying direction of the wire belt is arranged in front of the Hauptabsaugbereich and that a second suction region is arranged in the conveying direction of the wire belt behind the Hauptabsaugbereich. Expediently, the extraction speed in the main suction area or in the storage area of the nonwoven is set so that it is greater than the extraction speeds in the two further extraction areas. The extraction speeds in the first and / or in the second suction region are, according to one embodiment of the invention, between 2 and 10 m / s, in particular between 2 and 5 m / s.

A recommended embodiment of the invention is characterized in that the nonwoven fabric deposited on the screen belt is preconsolidated and is particularly preferably preconsolidated with the aid of at least one compaction roller as the preconsolidating device. Conveniently, the at least one compaction roller is formed heated. According to another embodiment of the invention, the preconsolidation of the web on the wire can also be done as a hot air hardening.

It is within the scope of the invention that a final consolidation of the nonwoven produced according to the invention is carried out. In principle, the final consolidation can also be carried out on the screen belt. According to the preferred embodiment explained below, however, the nonwoven fabric is removed from the wire belt and then subjected to final consolidation.

It is understood that the nonwoven web deposited on the screen belt has to be separated or removed again from the screen belt. Appropriately, this separation of the nonwoven web from the screen belt after the Pre-consolidation and preferably before a final consolidation. A particularly preferred embodiment of the invention is characterized in that, for separating the nonwoven from the wire, air (dissolving air) is blown through the wire from below or in the direction of the underside of the nonwoven. Preferably, a separate fan is provided for this purpose and it is recommended that the air injection takes place with respect to the conveying direction of the screen belt behind the at least one suction area or behind the suction areas and above all behind the storage area of the nonwoven. Has proven particularly useful in the context of the invention that the separation of the web or the arrangement of the fan for separating the web from the wire in the conveying direction of the wire behind at least one Vorverfestigungseinrichtung and in particular behind at least one Kompaktierwalze is arranged. Expediently, the blowing in of the dissolving air in the conveying direction of the fleece strip takes place shortly before the position at which the filament deposit is removed from the sieve belt in any case. According to the recommended embodiment of the invention, air or dissolving air is blown in at an air velocity of between 1 and 40 m / s for separating the nonwoven fabric. Preferably, at least one supporting surface for the fleece acted upon by the release air is additionally provided above the sieve belt. According to one embodiment, this is an air-permeable or permeable support surface which is actively evacuated according to a variant embodiment. As a support surface, for example, a co-rotating permeable drum can be used, the surface of which is preferably formed by a metal fabric. In addition or as an alternative, a co-rotating additional screen belt arranged above the screen belt can be provided as a support surface. - It is within the scope of the invention that the support surface - for example, designed as a drum or as additional screen belt support surface - is evacuated and is preferably sucked from above, so that the blown in from below Löseluft is sucked through the support surface.

For blowing in the release air for separating the nonwoven web from the wire belt, at least one injection gap arranged transversely to the conveying direction of the wire belt can be arranged below the wire belt. The gap width may be 3 to 30 mm. It is within the scope of the invention that the gap width of the Einblasspaltes is adjusted so that the deposited on the wire belt fleece for the separation of the web is just raised without being destroyed.

It is within the scope of the invention that the nonwoven - finally after a preconsolidation and preferably after separation from the wire belt - is finally solidified. The final consolidation can be carried out in particular with at least one calender or with at least one heated calender. In principle, the final solidification can also be carried out in other ways, for example as hydroentanglement, as mechanical needling or as hot air hardening.

An embodiment of the invention is characterized in that a laminate of spunbond nonwovens and a meltblown nonwoven can be produced with a device according to the invention. It is therefore within the scope of the invention to use a spunbond meltblown spunbond device (SMS) device. In such a device, two spunbond beams and one meltblown beam are used to wind the individual webs. For such a combination, the device according to the invention and the inventive method has proven particularly useful.

With a device according to the invention and / or with a method according to the invention, it is possible to produce a nonwoven from continuous filaments, wherein the endless filaments are preferably made of thermoplastic Consist of plastic or consist essentially. It is within the scope of the invention that the continuous filaments of this web have a denier of 0.9 to 10 denier. The filaments may also have a diameter of 0.5 to 5 microns. The nonwoven may be a spunbond nonwoven or a meltblown nonwoven. Particularly preferred is a spunbond nonwoven. The invention is based on the finding that a structured spunbonded fabric with locally different basis weights can be produced in a simple and cost-effective manner with the device according to the invention and with the method according to the invention. It is possible within the scope of the invention to produce such nonwovens in a functionally reliable and inexpensive manner in which restrictions of further positive properties need not be accepted. In particular, in comparison with the prior art, 3D-structured nonwoven webs with a soft feel can be produced in a simple and reproducible manner. The properties of the fleece can be specifically and easily varied according to the requirements. As a result, the device according to the invention and the method according to the invention are distinguished by low costs, low expenditure and functional reliability.

Fig. 1

einen Vertikalschnitt durch eine erfindungsgemäße Vorrichtung,

Fig. 2

einen stark vergrößerten Ausschnitt A aus der Fig. 1,

Fig. 3

eine Draufsicht auf ein erfindungsgemäß eingesetztes Siebband

1. a) in einer ersten Ausführungsform
2. b) in einer zweiten Ausführungsform,
3. c) in einer dritten Ausführungsform,
4. d) und in einer vierten Ausführungsform,

Fig. 4

einen vergrößerten Ausschnitt aus der Fig. 1 in einer ersten Ausführungsform und

Fig. 5

einen Ausschnitt aus der Fig. 4 in einer zweiten Ausführungsform.

The invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. In a schematic representation:

Fig. 1

a vertical section through a device according to the invention,

Fig. 2

a greatly enlarged section A from the Fig. 1 .

Fig. 3

a plan view of an inventively used screen belt

1. a) in a first embodiment
2. b) in a second embodiment,
3. c) in a third embodiment,
4. d) and in a fourth embodiment,

Fig. 4

an enlarged section of the Fig. 1 in a first embodiment and

Fig. 5

a section of the Fig. 4 in a second embodiment.

The figures show a device according to the invention for producing nonwovens 1 from continuous filaments 2. According to a particularly preferred embodiment and in the exemplary embodiment, these are spunbond devices for producing spunbonded nonwovens 1 or spunbonded nonwovens 1. The continuous filaments 2 are preferably made of thermoplastic material Plastic or substantially of thermoplastic material. In the apparatus according to the invention, the endless filaments 2 are spun with the aid of a spinning device designed as a spinnerette 3. Subsequently, the endless filaments 2 are cooled in a cooling device 4. This cooling device 4 preferably and in the exemplary embodiment has two cabin sections 4a, 4b arranged one above the other or in the filament flow direction, from which cooling air of different temperature is introduced into the filament flow space. The cooling device 4 is followed by a stretching device 5 downstream of the filament flow direction, and this stretching device 5 preferably has, in the exemplary embodiment, an intermediate channel 6 converging in the direction of flow of the endless filaments 2 and an adjoining drawing channel 7. Empfohlenermaßen and in the embodiment, the unit of the cooling device 4 and the drawing device 5 as a closed system educated. In this closed system, apart from the supply of cooling air or process air in the cooling device 4, no further air supply takes place.

According to a preferred embodiment of the invention and in the exemplary embodiment, at least one diffuser 8, 9 adjoins the drawing device 5 in the filament flow direction. Appropriately, and in the embodiment, two mutually or successively arranged diffusers 8, 9 are provided. It is recommended that an ambient air inlet gap 10 for the entry of ambient air is provided between the two diffusers 8, 9. It is within the scope of the invention that the continuous filaments 2 are deposited on a depositing device in the form of a screen belt 11 following the diffusers 8, 9. Furthermore, it is within the scope of the invention that this is an endlessly circulating screen belt 11.

The screen belt 11 has a screen belt surface 12 with a multiplicity of screen belt openings 13 distributed over the screen belt surface 12. According to the invention, air is sucked through the screen belt surface 12 or through the (open) screen belt openings 13. For this purpose, at least one exhaust fan, not shown in detail in the figures, is arranged below the screen belt 11. Preferably and in the embodiment, three separate suction regions 14, 15, 16 are arranged one behind the other in the conveying direction of the wire. In the storage area 17 of the endless filaments 2, a main suction area 15 is preferably provided, in which air is sucked through the sieve belt 11, for example at a suction speed or at a mean suction speed of 5 to 30 m / s. Expediently, the suction speed in the main suction region 15 is set so that it is greater than the suction speed in the further suction regions 14 and 16. A first suction region 14 is connected upstream of the main suction region 15 and a second suction region 16 is the main suction region 15 downstream. Appropriately and in the exemplary embodiment, a compacting device 18 with two compacting rollers 19, 20 for compacting or preconsolidating the nonwoven 1 is provided above the second suction region 16. Empfohlenermaßen and in the embodiment, at least one of the Kompaktierwalzen 19, 20 designed as a heated Kompaktierwalze 19, 20.

According to the invention, a part of the screen belt openings 13 of the screen belt 11 is designed to be closed. In that regard, closed Siebbandöffnungen 21 or closure points 22 result in the wire, the closure points 22 are composed of a closed Siebbandöffnung 21 or from several adjacent closed Siebbandöffnungen 21. It is understood that the air permeability of the unclosed screen belt 11 (only open Siebbandöffnungen 13) is greater than the air permeability of the provided with closed Siebbandöffnungen 21 screen belt 11. For example, the air permeability of the unclosed screen belt 600 cfm and the air permeability of the closed screen belt 11 - ie Air permeability of the screen belt 11 with partially closed Siebbandöffnungen 21 - only 350 cfm. The ratio of the air permeability of the unclosed screen belt 11 to the air permeability of the partially closed screen belt 11 is preferably 1.2 to 3. The air permeability is measured in particular transversely to the screen belt surface 12 at a circular area of 38.3 cm ^{2 of} the screen belt at a pressure difference of 125 Pa ,

Preferably, and in the embodiment, the screen belt 11, a fabric of the Siebbandöffnungen 13 delimiting warp threads 23 and weft threads 24. The diameter D or the smallest diameter D of a wire opening 13 may be 0.5 mm in the embodiment.

Appropriately, this involves the diameter D with respect to the threads or woven threads arranged on the surface or in a surface layer of the screen belt / screen belt webbing. Empfohlenermaßen, the fabric of the wire 11 has a weaving density of 20 to 75 warp / 25 mm and 10 to 50 wefts / 25 mm.

According to a preferred embodiment of the invention, the closure points 22 in the wire 11 are punctiform and / or linear. The Fig. 3a ) shows the punctiform formation of closure points 22 in the wire 11. The (smallest) diameter d of such a point-like closure point 22 may be 2 mm in the embodiment. In the embodiment according to Fig. 3b ) line-shaped closure points 22 are shown. The smallest width b of the linear closure points 22 may also be 2 mm in the exemplary embodiment. The Fig. 3c ) shows a further embodiment with broken line-shaped closure points 22. The line-shaped closure points 22 can be formed otherwise in a manner not shown as curved or arcuate lines. In the Fig. 3d ) an additional embodiment with crossed line-shaped closure points 22 is shown. This embodiment has proven itself. - The Fig. 3a), 3b) and 3d ) show, moreover, embodiments in which the closure points 22 is formed symmetrically with respect to the longitudinal direction or the conveying direction of the screen belt 11. The conveying direction F of the wire 11 is in the Fig. 3a) to 3d ) has been indicated by an arrow. In contrast, the embodiment according to Fig. 3c ) asymmetrical with respect to the longitudinal direction or with respect to the conveying direction F of the screen belt 11. The embodiments symmetrical with respect to the longitudinal direction or conveying direction F are preferred within the scope of the invention.

In the Fig. 4 is shown a particularly recommended embodiment of the device according to the invention. The continuous filaments 2 emerging from the diffuser 9 are deposited on the screen belt surface 12 in the depositing area 17 of the screen belt 11. Below the storage area 17 is the Hauptabsaugbereich 15 for the extraction of the process air through the wire 11 and through the Siebbandoberfläche 12. Following the Hauptabsaugbereich 15 of the second suction 16 is arranged, sucked in the process air with compared to Hauptabsaugbereich 15 lower air velocity becomes. Above the second suction region 16, the compacting device 18 with the two compacting rollers 19, 20 is provided. In the conveying direction of the web 1 then a separation region 25 is connected downstream. In this separation region 25, the nonwoven fabric 1 or the preconsolidated nonwoven fabric 1 is detached / separated from the wire belt 11 or from the wire belt surface 12. For this purpose, air is blown from below or in the direction of the underside of the web 1 through the wire 11. This is in the 4 and 5 has been clarified by corresponding arrows 26. According to a recommended embodiment and in the embodiment according to Fig. 4 the nonwoven fabric 1 acted upon by the release air is supported by an air-permeable or permeable drum 27 rotating in the conveying direction of the wire 11. The drum may, for example, be arranged at a distance of 0.5 to 5 mm above the screen belt surface 12. In this case, the surface of the drum 27 may be formed, for example in the form of a metal fabric. Instead of the drum also in the conveying direction of the wire 11 co-rotating additional screen belt (not shown) could be used.

The Fig. 5 shows a further embodiment of a provided for supporting the treated with the release air fleece 1 drum 27. In this embodiment, the drum 27 has a suction region 28 for receiving the release air and in addition is here in the direction of the wire 11 and Direction of the web 1 blown support air to prevent snagging of the endless filaments 2 and the web 1 on the drum 27. The support air is in Fig. 5 symbolized by an arrow 29.

Claims (15)

1. An apparatus for producing nonwovens (1) from continuous filaments (2), wherein at least one spinning device for spinning said filaments (2) is provided, wherein the filaments (2) are cooled and stretched and wherein a deposition device is provided for depositing the stretched filaments (2) to form the nonwoven (1),
   wherein the deposition device is implemented in the form of a foraminous belt (11) having a plurality of foraminous belt openings (13) distributed over the foraminous belt surface (12), wherein air can be sucked through the foraminous belt surface (12) or through the foraminous belt openings (13) and wherein at least one extraction fan is arranged underneath the foraminous belt (11),
   wherein a portion of the foraminous belt openings (13) is configured to be plugged, wherein the air permeability of the unplugged foraminous belt is between 300 to 1100 cfm (510 to 1870 m³/h), preferably 350 to 1050 cfm (595 to 1785 m³/h) and preferably 400 to 1000 cfm (680 to 1700 m³/h), wherein the air permeability of the partially plugged foraminous belt is 150 to 700 cfm (255 to 1190 m³/h), preferably 250 to 600 cfm (425 to 1020 m³/h) and preferably 350 to 500 cfm (595 to 850 m³/h)
   wherein the plugging mass of the plugged points (22) is arranged in and/or underneath the foraminous belt surface (12) and does not project beyond the foraminous belt surface (12) or projects by a maximum of 1.0 mm, preferably by a maximum of 0.8 mm, very preferably by a maximum of 0.6 mm and particularly preferably by a maximum of 0.3 to 0.6 mm beyond the foraminous belt surface (12).
2. The apparatus according to claim 1, wherein the foraminous belt (11) comprises a woven fabric comprising warp threads (23) and weft threads (24) delimiting the foraminous belt openings (13).
3. The apparatus according to one of claims 1 or 2, wherein the woven fabric of the foraminous belt (11) has a weave density of 20 to 75 warp thread/25 mm and preferably 30 to 50 warp threads/25 mm and of 10 to 50 weft threads/25 mm, preferably 10 to 40 weft filaments/25 mm.
4. The apparatus according to one of claims 1 to 3, wherein the smallest diameter d of a plugged point (22) of the foraminous belt (11) is at least 1.5 mm, preferably at least 2 mm and a maximum of 8 mm, preferably a maximum of 9 mm and particularly preferably a maximum of 10 mm.
5. The apparatus according to one of claims 1 to 4, wherein the ratio of the air permeability of the unplugged foraminous belt (11) to the air permeability of the partially plugged foraminous belt is 1.2 to 4, preferably 1.3 to 3.5, preferably 1.3 to 3 and particularly preferably 1.8 to 2.8.
6. The apparatus according to one of claims 1 to 5, wherein the plugged points (22) are configured to be punctuate and/or linear.
7. The apparatus according to one of claims 1 to 6, wherein the plugged points (22) are arranged distributed in a regular pattern over the foraminous belt (11).
8. The apparatus according to one of claims 1 to 7, wherein at least one cooling device (4) for cooling the filaments (2) and at least one stretching device (5) for stretching the cooled filaments (2) is provided, wherein the unit comprising cooling device (4) and stretching device (5) is configured as a closed unit and wherein apart from the supply of cooling air in the cooling device (4) no further air is supplied into this closed unit.
9. The apparatus according to one of claims 1 to 8, wherein at least one diffusor (8, 9) is arranged between the stretching device (5) and the deposition device, through which the filaments (2) can be guided before depositing on the deposition device.
10. The apparatus according to one of claims 1 to 9, wherein at least one compacting roller (19, 20) is provided for pre-consolidating the nonwoven (1) deposited on the deposition device or on the foraminous belt (11) and wherein the compacting roller (19, 20) is preferably configured to be heated.
11. Method for producing nonwovens from continuous filaments (2) - in particular using an apparatus according to one of claims 1 to 10 -, wherein the continuous filaments (2) are spun and then cooled and stretched and are then deposited on a deposition device in the form of a foraminous belt (11) with open and plugged foraminous belt openings (13) for the nonwoven (1), wherein for stabilizing the nonwoven (1) deposited on the foraminous belt (11) air is sucked through the foraminous belt (11) or through the foraminous belt surface (12), wherein the ratio of the air permeability of the foraminous belt (11) with exclusively unplugged foraminous belt openings (13) to the air permeability of the foraminous belt (11) with partially closed foraminous belt openings is 1.2 to 4, preferably 1.3 to 3.5, preferably 1.5 to 3 and particular preferably 1.8 to 2.8,
    and wherein the plugging mass of the plugged points (22) is arranged in and/or underneath the foraminous belt surface (12) and does not project beyond the foraminous belt surface (12) or projects by a maximum of 1.0 mm, preferably by a maximum of 0.8 mm, very preferably by a maximum of 0.6 mm and particularly preferably by a maximum of 0.3 to 0.6 mm beyond the foraminous belt surface (12).
12. The method according to claim 11, wherein the nonwovens (1) are produced as spunbond nonwovens.
13. The method according to one of claims 11 or 12, wherein in the deposition region (17) of the nonwoven (1) air is sucked at a suction rate of 5 to 25 m/s through the foraminous belt (11).
14. The method according to one of claims 11 to 13, wherein the deposited nonwoven (1) is pre-consolidated and it is recommended that it is finally consolidated.
15. The method according to one of claims 11 to 14, wherein to separate the nonwoven (1) from the foraminous belt (11) air is blown through the foraminous belt (11) from below or in the direction of the underside of the nonwoven (1).

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