WO2015000685A1

WO2015000685A1 - Method and apparatus for producing nonwoven material

Info

Publication number: WO2015000685A1
Application number: PCT/EP2014/062619
Authority: WO
Inventors: Herbert Aust; Kai PÖHLER
Original assignee: Voith Patent Gmbh
Priority date: 2013-07-04
Filing date: 2014-06-17
Publication date: 2015-01-08

Abstract

In a method for producing a nonwoven material, a nonwoven is formed in a former and the resulting nonwoven material web is subsequently dewatered. In this case, according to the invention, the dewatering of the nonwoven material web comprises dewatering by means of a belt press, wherein the belt press comprises a roller about which at least one inner belt, preferably configured as an endless belt, that rests against the roller, and an outer pressing belt, preferably configured as an endless belt, are wrapped in order to form an extended press nip, wherein the nonwoven material web is arranged at least in the region of the roller between the inner belt and the outer pressing belt, and wherein, in order to generate a mechanical pressure on the nonwoven material web located between the two belts, the pressing belt is pressed with a belt tension of at least 15 kN/m against the roller and as a result the nonwoven material web and the inner belt are pressed against the roller. In this case, the nonwoven material web is guided, following the belt press, through a TAD ("through air drying") device which comprises no more than one TAD cylinder, in order to bring the nonwoven material web to the final dry content. An apparatus suitable for carrying out the method is also specified.

Description

The present invention relates to a method and an apparatus for producing a nonwoven fabric.

A nonwoven web is a web of limited length fibers, filaments or cut yarns of any kind and origin, which in some way form a nonwoven (ie, a fibrous web) and in some way have been joined together. Nonwoven fabrics include fiber webs made by interlacing yarns such as those used in weaving, knitting, knitting, lace making, braiding and the manufacture of tufted products. Also films and papers are not among the nonwovens.

Known processes for the production of nonwovens generally include nonwoven formation, nonwoven bonding and subsequent dewatering. Different methods of web formation are, for example, in WO

2007/018960 A2. In this case, the nonwoven can be formed in particular by a dry process, a wet process and / or an extrusion process. In principle, any combinations of such web-forming methods are also conceivable.

The subsequent nonwoven consolidation can be effected, for example, mechanically or by the so-called hydroentanglement process, which is also called "spunlacing". In principle, however, other conceivable. In the hydroentanglement process, the formed web is solidified by entangling the fibers, the entangling being effected by swirling, in particular by the fact that focused high-pressure water jets act on the web.

In particular, after such a solidification by the hydroentanglement process, the formed nonwoven material web has a relatively high humidity, which subsequently has to be removed again from the material web.

In order to reduce the costs for the subsequent drying process and in particular a subsequent thermal drying, suction tubes or suction boxes subjected to vacuum have hitherto been used following the hydroentanglement. With such suction tubes or suction boxes wanted to increase the dry content of the nonwoven web as much as possible, without sacrificing volume.

However, such drainage using suction pipes or suction boxes brings a number of disadvantages. Thus, the drainage performance of suction boxes is limited. They are still used because they practically do not affect the product quality parameters, whereas an alternative to mechanical dewatering would negatively impact many products. Due to the limited drainage capacity of suction pipes or

Suction boxes can make the subsequent dryer section a bottleneck in terms of production capacity. Currently, this problem is addressed by increasing the drying capacity. In addition, by suction pipes or

Suction boxes destroys or at least impairs the desired uniform moisture cross profile of the nonwoven material web, which is attributable in particular to air losses at the material web edges due to a non-constant width of the material web and to the technology of some suction tubes or boxes. lead is. A non-uniform moisture cross-section can bring about limitations of the production process, in particular with regard to thermal hardening. The air loss at the material web edges also brings a high energy consumption with it. Depending on the basis weight, nonwoven composition and structure of the nonwoven material web, which may also be structured or perforated, for example, the dry content of the nonwoven material web obtained after dewatering is limited. As a result of the relatively high vacuum, it may be present on the transfer belt concerned, via which the nonwoven web is fed via the suction tubes or boxes, which is usually a fabric belt, a forming fabric or a nonwoven structuring and / or perforating structuring belt, come to a loss of fibers by so-called "fiber plucking". The plucked fibers pollute the wastewater and are lost to the manufacturing process. Moreover, these fibers entail additional contamination of the water reprocessed for hydroentanglement, thus necessitating additional filtration steps and a more expensive recycle system, eg, where fresh pulp must be added. Fiber losses occur mainly due to air losses at the edges of the nonwoven web, cracking and / or breakage of the fibers and suction of the fibers into the suction boxes. For certain products, in particular those for which substance mixtures are used, in particular the relatively large suction forces lead to fiber loss.

Fibers drawn into the dewatering system tend to contaminate the water used for water-jet solidification and make regeneration and filtration more difficult, particularly when using fiber pulp.

For example, DE 10 2006 042 507 A1 discloses the use of a shoe press for dewatering a nonwoven material web. Such a shoe Although viewed in the web running direction, the press has an extended press nip or press nip compared with a nip. Due to the relatively high pressure of the shoe press, however, it comes before the press nip the shoe press to a disturbing water retention. In addition, the relatively high pressure of the shoe press leads to a reduction in the volume of the nonwoven fabric.

Therefore, the invention has for its object to provide a method and an apparatus of the type mentioned, with which the aforementioned problems are eliminated in the simplest and most reliable manner. In particular, an efficient and cost-effective drainage of the formed nonwoven material web is to be achieved, which leads to a nonwoven material web with the largest possible volume and with a uniform moisture cross profile while avoiding a water jam. In the process, the highest possible dry content of the nonwoven material web should be achieved even before the drying section, and the overall energy consumption should be reduced. In addition, the fiber losses should be kept as low as possible and overall the dewatering efficiency and the drying efficiency should be increased. According to the invention this object is achieved by a method according to claim 1 and an apparatus according to claim 38 and in particular by a method for producing a nonwoven fabric, in which a nonwoven fabric is formed in a former and then the resulting nonwoven material web is further dehydrated, wherein the further dewatering of the nonwoven material web according to the invention comprises dewatering by means of a belt press, wherein the belt press comprises a roller around which - to form an elongated press nip or press nip - at least one inner strip resting against the inner strip and an outer pressing strip in each case are wrapped at certain wrapping angles, wherein the nonwoven material web is arranged at least in the region of the roller between the inner band and the outer press belt, and wherein the press belt - to generate a mechanical pressure on the lying between the two bands nonwoven web - is pressed with a belt tension of at least 15 kN / m to the roll and thereby the

Nonwoven web and the roller contacting inner band are pressed against the roller. After the belt press, the nonwoven web is passed through a through air drying (TAD) device which comprises no more than one TAD cylinder to bring the nonwoven web to the final dry content. It goes without saying that in carrying out the method, the nonwoven web and the bands run around the roller, so that both the inner band and the outer press belt are preferably designed as endless belts.

Very particular preference is given to using (endless) tapes for the inner band and the outer press belt of the belt press for drying fluid and preferably for air and / or water vapor permeable (endless) belts and is used simultaneously with the pressing of the nonwoven material web against the Roll or simultaneously with the mechanical pressurization of the nonwoven fabric web, a drying fluid through the permeable (endless) belts and the nonwoven fabric web pressed, preferably by generating a corresponding pressure difference between the roller and the outer press belt, the roller of the Belt press is designed for dispensing or receiving the drying fluid with an open surface.

In addition, it is preferred that at least one (endless) strip wound around the roller of the belt press is permeable to water or designed to receive water in order to absorb the water produced during the mechanical pressing occurring in the belt press and / or to be allowed to pass. Since even with the use of only a single TAD-Durchströmzylinders or TAD-Trockenzyl inder a single TAD or air drying device a higher solids content of the nonwoven material web than usual achieved and high production performance is ensured, the inventive method is very energy efficient.

In the TAD (through-air drying) process, large volume flows of hot air or superheated steam are pressed by means of pressure hoods and fans through the nonwoven material web lying on the inner band and guided through a large flow-through cylinder. The diameter of the throughflow cylinder of the TAD or air drying device is preferably set or selected to be less than 4 m, preferably less than 3.5 m and particularly preferably less than 3 m. For the purposes of the present invention, nonwoven is understood to mean a nonwoven fabric of low consistency obtained directly by molding, whereas a nonwoven fabric is understood as meaning a nonwoven already having a higher consistency than and having preferably solidified nonwoven immediately after shaping. For the purposes of the present invention, belt tension of the outer press belt is understood to mean the quotient of the tension applied to the press belt and the width of the press belt, in accordance with the usual use of this term. Due to this embodiment of the method results in a total more efficient, more cost-effective drainage of the formed nonwoven material web, while avoiding the previously occurring particularly in connection with a shoe press water accumulation before the press nip - compared to the use of a shoe press - a larger volume of manufactured

Nonwoven material web is achieved because the pressure in the extended press nip the belt press is lower than a shoe press. However, as a result of the longer residence time of the nonwoven material web in the nip compared to the use of a shoe press, efficient drainage with a high degree of dewatering is ensured despite the lower compacting pressure. Due to this, the thermal drying device still provided after the belt press, namely the TAD (Through Air Drying) or air drying device, requires only one flow-through cylinder and therefore only a very small amount of energy. In addition, in the method according to the invention due to the belt press used in comparison to the known from the prior art method a very gentle and - based on the surface of the nonwoven material web - very uniform drainage achieved, so that an impairment or even destruction of Fiber structure is reliably prevented. Due to this, fiber losses as well as contamination of the waste water are kept to a minimum. Moreover, the process according to the invention also gives an improved moisture cross profile for the nonwoven fabric formed.

The inventive method also makes it possible to transfer the nonwoven material web with a higher solids content to the final, in particular thermal drying device, whereby the machine speed is increased in the dryer section. Due to the reduced pressure in the belt press, the volume of the nonwoven web is reduced by no more than 10% in the dewatering. Thus, the solids content of the nonwoven web can be increased relative to the water content by more than 10% compared to the usual dewatering by suction boxes, resulting in a higher production capacity, energy consumption is reduced and the provision of additional or more expensive drying facilities is avoided. Since the nonwoven material web in the belt press is additionally additionally acted upon by the drying fluid, the efficiency of the shock absorber is improved. and even drainage without loss of volume.

In principle, any inert gas or aerosol can be used as the drying fluid, with good results, in particular with air and / or steam.

If air is used as the drying fluid, it may, for example, have ambient temperature. Alternatively, hot air may be used as the drying fluid, preferably hot air at a temperature in a range of 50 ° C to 250 ° C, more preferably at a temperature in a range of 150 ° C to 250 ° C, and more particularly preferably at a temperature in a range of 175 ° C to 225 ° C, such as at a temperature of about 200 ° C.

When water vapor is used as the drying fluid, it is preferably used in a steam weight / weight ratio of the nonwoven web of up to 2 kg of steam / kg of nonwoven web and preferably in a ratio of steam weight of the nonwoven web of 0.1 to 1 kg Steam / kg nonwoven web, such as in a steam weight / weight ratio of the nonwoven web of about 0.5 kg steam / kg nonwoven web.

As a roll having an open surface, in particular, a suction roll or a blow roll can be used.

If the roller of the belt press is designed as a suction roll, the drying fluid is expediently sucked or guided, starting from a drying fluid hood, at least through the permeable outer press belt, the nonwoven material web and the permeable inner band into the suction roll. Next to the Drying fluid is expediently also sucked or guided in the tape press dehydrated water in the suction roll or the permeable inner band. For this purpose, the suction roll is preferably provided with a negative pressure (ie a difference between atmospheric pressure and the pressure prevailing in the suction roll) in the range from 0.25 bar to 0.6 bar and particularly preferably at a negative pressure in the range of 0.30 bar to 0.55 bar, as for example, with a negative pressure of about 0.45 bar, applied.

If the roller of the belt press is designed as a blow roll, the drying fluid is preferably blown from the blow roll at least through the permeable inner (endless) band, the nonwoven material web and the permeable outer (endless) band preferably in a hood. In addition to the drying fluid, the water dewatered in the belt press is expediently also blown or guided into the hood or the permeable outer band. In this embodiment of the present invention, it is preferred that the drying fluid at a pressure in the range of 0.25 bar to 0.6 bar, and more preferably at a pressure in the range of 0.30 bar to 0.55 bar, such as with a pressure in the range of about 0.45 bar, is blown above the atmospheric pressure through the permeable inner band, through the nonwoven web and through the permeable outer press belt to the hood.

When the nonwoven material web in the belt press, which is preferred as stated above, is subjected to a drying fluid in addition to the pressurization, the pressure exerted on the nonwoven web also depends, inter alia, on the flow of drying fluid. In order to achieve a particularly good, gentle and uniform drainage, it is proposed in a further development of the inventive concept in this embodiment that a drying fluid flow in a range of 100 through the belts m ³ / (m ² NNIN) to 300 m ³ / (m ² NNIN), preferably from 150 to 250 m ³ / (m ² NNIN) and most preferably of about 210 m ³ / (m ² NNIN) is generated.

If the roller of the belt press is still surrounded by one or more other (endless) belts in addition to the inner and the outer (endless) belt, then these other (endless) belts must also be permeable to the drying fluid, provided that the nonwoven fabric Material web in the belt press to be acted upon by such a drying fluid, which - as stated above - is particularly preferred.

In order on the one hand to achieve a sufficiently high degree of dewatering but on the other hand to carry out the dewatering as gently and uniformly as possible, it is provided according to a particularly preferred embodiment of the present invention that in the process at least the outer band (endless) serving as a press belt has a belt tension from 20 to 100 kN / m, preferably with a belt tension of 25 to 75 kN / m and particularly preferably with a belt tension of 40 kN / m to 50 kN / m is pressed against the roller of the belt press. With regard to a sufficiently good, but at the same time as gentle and uniform dewatering, it is particularly advantageous if in the belt press on the nonwoven material web, a mechanical pressure of less than 140 kPa, in particular less than 100 kPa and preferably less than 90 kPa , but of more than 30 kPa and preferably more than 45 kPa is exercised. With such a low pressure, in particular a higher volume of the nonwoven fabric is achieved while avoiding the water accumulation occurring in shoe presses, because due to the low pressure no significant compaction of the

Nonwoven fabric and therefore no significant volume loss occurs. Also in view of a sufficiently good, but at the same time as gentle and uniform drainage, it is proposed in development of the invention, the residence time of the nonwoven material web in the extended press nip of the belt press on between 0.05 sec and 0.5 sec set. With such a relatively long residence time, an efficient drainage is ensured despite the relatively low pressure and the correspondingly gentle treatment of the nonwoven material web.

According to a particularly preferred embodiment of the present invention, the nonwoven material web is dewatered in the belt press by at least 20%, preferably by 30 to 75% and particularly preferably by 33 to 50%. In this case, this degree of dewatering denotes the percentage weight loss in the dewatering based on the total weight of the nonwoven material web prior to dewatering in the belt press.

In certain cases, it may be advantageous if the belt press with only two roll wrapping the (endless) provided bands and the nonwoven material web between these two (endless) bands and the bands is arranged touching. In this case, both the inner (endless) belt and the outer press belt contact the nonwoven web.

In an alternative embodiment, the belt press except the inner and the outer (endless) band may also be provided with at least one further (endless) band wrapping the roller in a predetermined wrap angle. In this case, the at least one further (endless) band can be arranged in particular between the outer press belt and the nonwoven material web.

Preferably, the (endless) bands wrapping the roller of the belt press comprise at least one felt belt and / or a fabric belt. It is It is particularly advantageous if a felt belt is used as the inner band of the belt press (endless). This also applies in particular if the nonwoven material web in the belt press is simultaneously passed through by a drying fluid and a suction roll is used as the roller of the belt press. If a blow roll is used as the roll, it is possible in particular for at least one outer (endless) band, which is viewed behind the nonwoven material web, to be provided as a felt band in the direction of flow of the drying fluid. Dewatering on a felt belt results in a substantially more uniform moisture cross profile than is the case, for example, in the case of dewatering by means of a suction box. In addition, with the drainage of a felt and the fiber losses are reduced.

In particular, in the case that the nonwoven material web in the belt press is preferably acted upon simultaneously by a drying fluid, all wound around the roller of the belt press (endless) belts for the drying fluid are made permeable or permeable.

In addition, it is preferred that at least one (endless) band wrapped around the drum of the belt press is permeable to water or adapted to receive water to absorb and / or accumulate the water produced by the mechanical press in the belt press to let pass.

As an outer (endless) band of the belt press, for example, an at least substantially smooth belt and preferably a smooth forming belt can be used.

If a structured and / or perforated nonwoven fabric is to be produced by the method according to the invention, it is provided according to a preferred embodiment of the present invention that at least one of the nonwoven fabric Web-contacting (endless) band of the belt press is provided as a structured band by which the nonwoven web is structured and / or perforated accordingly. If the nonwoven material web in the belt press is preferably also subjected to a drying fluid simultaneously with the pressurization and more than two permeable (endless) belts are wound around the roller of the belt press, these (endless) belts can be viewed in particular in the direction of flow of the drying fluid For example, a permeable (endless) belt, an endless smooth forming fabric, an endless permeable fabric belt, and an endless permeable felt belt. In principle, however, it is also possible to provide fewer or more (endless) bands and / or a different sequence of these (endless) bands. According to a preferred embodiment of the present invention, the roller of the belt press is designed as a suction roll and comprise the roll-wrapping belts in the direction of flow of the drying fluid a) a permeable press belt stretched around the roll, a permeable fabric belt and a permeable felt belt, or

b) a permeable press belt stretched around the roll, a permeable wire belt, a permeable fabric belt and a permeable felt belt, or

c) a permeable press belt stretched around the roll, a permeable felt belt, a permeable fabric belt and a permeable felt belt, or

d) a permeable felt press belt stretched around the roll, a permeable fabric belt and a permeable felt belt.

According to another preferred embodiment of the present invention, the roller of the belt press is designed as a blow roll and comprise the belts wrapping the roll in the direction of flow of the drying fluid a) a permeable press belt stretched around the roll, a permeable fabric belt and a permeable felt belt, or

d) a permeable felt press belt stretched around the roll, a permeable fabric belt and a permeable felt belt. The (endless) bands of the belt press are suitably looped around the roller over the same angle of wrap.

Regardless of whether the wrap angle of the individual bands are the same or different, it is proposed in development of the invention that the wrap angle of the inner band and / or outer press belt around the roller in a range of 90 ° to 180 ° and in particular in a Range of 100 ° to 120 ° is selected. As a result, a residence time of the nonwoven material web required for a sufficiently high and at the same time gentle, uniform dewatering is achieved in the press nip of the belt press. In principle, the residence time of the nonwoven material web in the press nip at the same roll diameter and the same roll revolution speed is the greater the greater the wrap angle of the belts. According to a further particularly advantageous embodiment of the method according to the invention, the diameter of the roller of the belt press is selected in a range of 500 mm to 1400 mm and preferably in a range of 750 mm to 1200 mm. Since the pressure exerted on the nonwoven web in the belt press depends inter alia on the angle of wrap of the (endless) belts and on the diameter of the roller of the belt press such a relatively large diameter a relatively long press nip and a correspondingly efficient dewatering due to the longer residence time of the nonwoven material web in the press nip. In principle, the greater the diameter of the roll, the greater the residence time of the nonwoven material web in the press nip at the same wrap angle of the belts and the same roll revolution speed.

If required, the nonwoven material web can be guided through an additional dewatering press between the belt press and the thermal drying device. In such an optional additional dewatering press, a line force in a range of 20 kN / m to 100 kN / m, and more preferably a line force in a range of 50 kN / m to 90 kN / m, is preferably produced to provide a gentle and uniform, but nevertheless to achieve strong drainage.

According to a preferred embodiment of the device according to the invention, the nonwoven material web is guided in the process according to the invention in a closed train of the former at least up to the belt press and preferably up to one of these downstream Wärmrocknerseinrich- device. In this case, the transfer of the nonwoven material web from the former to the belt press or up to this downstream thermal drying device via a single transfer belt. According to a further preferred embodiment of the device according to the invention, the transfer belt is formed by the forming fabric on which the web is formed in the former. In particular, in the case that the nonwoven material web is guided in a closed train at least up to the belt press, a hydroentanglement can be omitted. In this case, the nonwoven fabric can be formed in the former by any method known to those skilled in the art, preferably by a dry method, wet method and / or an extrusion method. For example, the nonwoven may be formed in the former at least partially by a wet process, in which the fibers are in particular suspended in water and deposited on a water-permeable support.

As an alternative or in addition to this, the nonwoven in the former can also be aerodynamically formed at least partially. The fleece is formed by depositing fibers by means of an air flow on an air-permeable base.

Alternatively or in addition to this, the nonwoven in the former can also be formed at least partially mechanically. In this case, it may be formed, at least in part, from carded or carded piles, which are laid one on top of the other, or formed by carding machines.

Alternatively or additionally, the nonwoven may be formed, at least in part, by the so-called spunbond process in which the nonwoven is formed by depositing fibers spun from a polymer melt passing through nozzles and drawn by cold air and / or mechanically drawn becomes. As an alternative or in addition to this, the nonwoven in the former can finally be formed at least partially by the so-called melt-blow process. In this case, the nonwoven fabric is formed by depositing fibers which are directly spun from a polymer melt passing through nozzles and drawn to rupture by means of hot air streams. In principle, the nonwoven fabric may be formed in the former not only by one of the aforementioned methods, but also, in particular, by any combination of two or more of said methods. The formed web can be consolidated prior to transfer of the resulting nonwoven web into the belt press by a consolidation process which preferably comprises mechanical consolidation, hydroentanglement, and / or the like. The use of a hydroentanglement device in combination with the belt press has the particular advantage that the nonwoven material web can be transferred to the belt press in an open draw. However, such solidification is not always mandatory. After the hydroentanglement process, the formed web is solidified by entangling fibers to the nonwoven web, which is done by tumbling, in particular by focusing high pressure water jets on the web. Advantageously, the fleece can be simultaneously structured and / or perforated by the application of water jet. A hydroentanglement, however, is not mandatory and may be omitted in particular when the nonwoven fibrous web is transferred in a closed train, such as by a single transfer belt, at least up to the belt press.

The material input into the former can i) at least partially from natural fibers, preferably from northern bleached kraft pulp (NBKP), hardwood pulp (LBKP), pulp from abaca fibers or cotton, ii) at least partially from artificial fibers, preferably from viscose, iii) at least partially made of synthetic fibers, preferably of polyester or polyamide, iv) at least partially made of mineral fibers, preferably glass fibers, v) at least partially made of carbon fibers and / or vi) consist of a mixture of any of the aforementioned substances. In this case, the substance entry into the former can advantageously at least partially consist of fibers which are longer than 2 mm, preferably longer than 3 mm and particularly preferably longer than 4 mm. The nonwoven material web is preferably produced from a plurality of different nonwoven partial webs and with variable proportions of polyester, pulp, cotton and / or the like.

According to a further preferred and expedient embodiment of the method according to the invention, in particular for producing a nonwoven material web having a basis weight of greater than 50 g / m ² , preferably greater than 80 g / m ² and particularly preferably greater than 100 g / m ² the

Nonwoven material web before or after the belt press additionally guided over a vacuum applied suction roll.

Finally, ie after the last drying step, the nonwoven fabric can still be thermally and / or chemically solidified, if this requires the subsequent use of the nonwoven fabric. Another object of the present invention is a suitable in particular for carrying out the method according to the invention suitable apparatus for producing a nonwoven fabric comprising a former for forming a nonwoven and a belt press for subsequent further dewatering of the nonwoven web formed from the formed nonwoven. According to the invention, the belt press comprises a roller around which - to form an extended press nip - at least one inner band resting against the roller, in particular an endless belt, and an outer press belt, in particular an endless belt, are wound in a certain angle of wrap, the nonwoven fabric Material web at least in the region of the roller between the inner band and the press belt can be arranged and preferably arranged, wherein the press belt - For generating a mechanical pressure on the lying between the two (endless) bands nonwoven fabric web - pressed with a belt tension of at least 15 kN / m to the roller and preferably pressed, whereby both the nonwoven material web and the Roller contacting inner (endless) belt pressed against the roller. Downstream of the belt press is a through-air drying (TAD) device, which includes no more than one TAD cylinder, to bring the nonwoven web to the final dry content. As already stated, the diameter of the throughflow cylinder of the TAD or air drying device is preferably less than 4 m, preferably less than 3.5 m and particularly preferably less than 3 m.

According to a very particularly preferred embodiment of the present invention, it is provided that the (endless) bands of the belt press are designed as compared to drying fluid and preferably against air and / or water vapor permeable (endless) bands that simultaneously with the pressing of the nonwoven material web against the roll or simultaneously with the mechanical pressurization of the nonwoven material web by the belt press, preferably by a pressure difference between the roller and the outer press belt, a drying fluid can be flowed through the permeable (endless) belts and the nonwoven material web wherein the roller of the belt press is adapted to discharge or receive the drying fluid having an open surface.

In addition, it is preferred that at least one (endless) band wrapped around the drum of the belt press is permeable to water or adapted to receive water to absorb and / or accumulate the water produced by the mechanical press in the belt press to let pass. As already mentioned, air or water vapor may be provided as the drying fluid, in the case of the use of air having this ambient temperature or as hot air, in particular with a temperature in a range of 50 ° C. to 250 ° C., preferably at a temperature in a range from 150 ° C to 250 ° C, and more preferably at a temperature in a range from 175 ° C to 225 ° C, such as at a temperature of about 200 ° C, may be provided. If water vapor is used as the drying fluid, it can be used, in particular, in a steam weight / weight ratio of the nonwoven material web of up to 2 kg steam / kg nonwoven material web and preferably from 0.1 to 1 kg steam / kg nonwoven material web, such as 0 , 5 kg steam / kg nonwoven web, are used. For this reason, it is preferred according to the invention that the device is designed such that one of the above-mentioned drying fluids can be flowed through the permeable belts and the nonwoven material web.

According to a preferred embodiment, the roller of the belt press is designed as a suction roll, wherein it is proposed in this embodiment in development of the inventive idea that the suction roll is designed so that the drying fluid preferably from a drying fluid hood at least by the permeable outer press belt, the Nonwoven material web and the permeable inner (endless) tape can be sucked into the suction roll. In addition, at least one (endless) belt is preferably designed such that, in addition to the drying fluid, the water dehydrated in the belt press can also be sucked or guided into the suction roll or the permeable inner belt. In this case, the suction roll is advantageously designed so that it can be acted upon with a negative pressure in the range of 0.25 bar to 0.6 bar, preferably from 0.30 bar to 0.55 bar and more preferably from about 0.45. According to another preferred embodiment, the roller of the belt press is designed as a blow roll, wherein the roll in this embodiment particularly preferably designed so that the drying fluid from the blow roll at least by the permeable inner (endless) band, the nonwoven material web and the permeable outer Press belt can be preferably blown to a hood. In addition, at least one (endless) belt is preferably designed so that, in addition to the drying fluid, the water drained in the belt press can also be blown or guided into the hood or the permeable outer belt. In this embodiment, the device is preferably designed such that the drying fluid is at a pressure in the range of 0.25 bar to 0.6 bar and particularly preferably from 0.30 bar to 0.55 bar from the blow roll through the permeable inner ( Endless) tape, the nonwoven web and the permeable outer press belt is blown. Advantageously, at least the outer press belt with a belt tension of 20 to 100 kN / m, preferably with a belt tension of 25 to 75 kN / m and particularly preferably with a belt tension of 40 to 50 kN / m can be pressed against the roller of the belt press. It is particularly advantageous if the belt press is designed so that a mechanical pressure of less than 140 kPa, preferably less than 100 kPa and more preferably less, on the nonwoven material web in the belt press or in the extended nip of the belt press than 90 kPa on the nonwoven web is exercisable.

In addition, it has proven advantageous in certain cases, when the belt press with only two rolls wrapping the (endless) provided bands and the nonwoven material web between these two (endless) bands, the bands arranged touching and preferably arranged. In this case, both the inner and outer press belts contact the nonwoven web. However, in addition to the inner and the outer (endless) band, the band press may also be provided with at least one further (endless) band wrapping around the roller at a predetermined wrap angle. In this embodiment, the at least one further (endless) band is preferably arranged or arranged between the outer press belt and the nonwoven material web.

Furthermore, it is preferred that the (endless) bands wrapping around the roller of the belt press comprise at least one felt belt and / or at least one fabric belt. In this case, in particular, the inner (endless) belt wrapping around the roller of the belt press can be designed as a felt belt. If the nonwoven material web in the extended press nip of the belt press, which is preferred as outlined, is also traversed by a drying fluid in addition to the pressurization, it may be advantageous to use a permeable (preferably in contact) direction behind the nonwoven material web and preferably touching it. Endless) tape should be designed as a felt belt.

In particular, in the case of a nonwoven material web additionally flowed through by a drying fluid, it is preferable that all (endless) belts wound around the roller of the belt press are permeable or permeable to the drying fluid.

In addition, it is preferred that at least one (endless) band wrapped around the drum of the belt press is permeable to water or adapted to receive water to absorb and / or accumulate the water produced by the mechanical press in the belt press to let pass. If the nonwoven material web is additionally to be subjected to a drying fluid in the extended press nip of the belt press, then the roller of the belt press can be designed in particular as a suction fan as a blower roll. According to a preferred embodiment of the present invention, the roller of the belt press is designed as a suction roll and comprise the roll-wrapping belts in the direction of flow of the drying fluid a) a permeable press belt stretched around the roll, a permeable fabric belt and a permeable felt belt, or

According to another preferred embodiment of the present invention, the roller of the belt press is designed as a blow roll and comprise the belts wrapping the roll in the direction of flow of the drying fluid

a) a permeable press belt stretched around the roll, a permeable fabric belt and a permeable felt belt, or

d) a permeable felt press belt stretched around the roll, a permeable fabric belt and a permeable felt belt. In certain cases, it is also advantageous if at least one nonwoven fabric web contacting (endless) band of the belt press is designed as a structured band through which the nonwoven material web is structurally structured and / or perforated.

According to a further expedient practical embodiment of the device according to the invention comprise the roller of the belt press wraps (endless) bands, especially in the flow direction of the drying fluid considered a permeable (endless) band, an endless smooth forming fabric, an endless fabric belt and an endless felt belt.

Preferably, the (endless) bands of the belt press are looped around the roller over the same wrap angle. Regardless of whether or not the tapes have the same wrap angle, it is preferable that the wrap angle of the inner tape and / or outer press belt around the roll is in a range of 90 ° to 180 °, and more preferably in a range of 100 ° to 120 ° ° is. It is particularly advantageous if the diameter of the roller of the belt press is in a range of 500 mm to 1400 mm and in particular in a range of 750 mm to 1200 mm.

In a further development of the inventive concept, it is proposed to design the device in such a way that the residence time of the nonwoven material web in the press nip formed in the belt press is adjustable within a range of 0.05 to 0.5 sec.

If the nonwoven material web in the extended nip of the belt press - as preferred - in addition to the pressurization of a dry Flowing through the fluid, the device is preferably designed so that in the belt press a drying fluid flow in a range of 100 m ³ / (min ^" m ² ) to 300 m ³ / (min ^" m ² ), preferably from 150 to 250 m ³ / (min m ² ) and more preferably of about 210 m ³ / (min m ² ) is generated.

According to a further preferred embodiment of the device according to the invention, the nonwoven material web is guided in a closed train of the former at least up to the belt press and preferably up to one of these downstream drying device. In this case, the transfer of the nonwoven material web from the former to the belt press or up to this downstream thermal drying device via a single transfer belt. According to a further preferred embodiment of the device according to the invention, the transfer belt is formed by the forming fabric on which the web is formed in the former. If the nonwoven material web is guided in a closed train at least up to the belt press, then a hydroentanglement can be dispensed with.

In particular, for producing a nonwoven material web having a weight per unit area of greater than 50 g / m ² , preferably greater than 80 g / m ² and particularly preferably greater than 100 g / m ² , the nonwoven material web may additionally be provided before or after the belt press be guided over a vacuum applied suction roll.

In the above embodiment, an additional dewatering press may be provided between the belt press and the thermal dryer, preferably a line force in a range of 20 kN / m to 100 kN / m and preferably a line force in a range of 50 kN / m to 90 kN / m can be generated. Preferably, the former is designed such that in this a nonwoven fabric by a dry process, a wet process and / or an extrusion process can be produced. In addition, it is preferred if between the former and the belt press means for solidifying the formed web to a nonwoven material web is arranged, wherein the device is preferably a hydroentanglement. The invention will be described in more detail by means of embodiments with reference to the accompanying drawings; in this show:

Fig. 1 is a schematic representation of a conventional apparatus for producing nonwovens

Fig. 2 is a schematic representation of a first exemplary

Embodiment of the device according to the invention,

Fig. 3 is a schematic representation of another exemplary

Embodiment of the device according to the invention with an additional suction roller upstream of the belt press and an additional belt press downstream

Dewatering press and

Fig. 4 is a schematic representation of another exemplary

Embodiment of the belt press of the device according to the invention with a hood arranged above the roller of the belt press for dispensing or receiving drying fluid. 1 shows a schematic representation of a conventional apparatus 10 for the production of nonwovens with a former 12, a hydroentanglement device 14, a plurality of suction tubes or suction boxes 16 comprehensive drainage device 18 and two thermal drying devices 20, namely two TAD or air drying devices, an immersion 22nd for loading the dried nonwoven material web with a finishing agent and a winding device 24.

In the forming machine 26 comprising a former 12, the nonwoven fabric is formed by the wet process with a low consistency.

In this known device 10, in particular due to the suction pipes or boxes 16 comprehensive drainage device 18, the aforementioned problems arise.

From FIG. 2, the basic principle of the nonwoven fabric production according to the invention is first given by way of example.

Thereafter, the web is formed in a former 28 of a subject apparatus 30 for producing nonwoven webs by a particular method or combination of such methods. The formed web is, for example, consolidated mechanically, by means of a hydroentanglement device 32 and / or the like, and then further dehydrated the solidified nonwoven material web. As can be seen from the following, however, an amendment is not always mandatory.

The further dewatering of the nonwoven material web formed from the formed nonwoven material comprises a dewatering by means of a belt press 34 with a roller 36 around which at least one inner endless belt contacting the roller for forming an extended press nip 38 over a respective wrap angle. band 40 and serving as a press belt outer endless belt 42 is looped.

In the former 28, the nonwoven may be formed in particular by a dry process, a wet process and / or an extrusion process.

The outer endless belt 42 of the belt press 34, which serves as a press belt, is stretched around the roll 36 or against this roll with a belt tension of at least 15 kN / m for generating a mechanical pressure on the nonwoven material web lying between the two endless belts 40, 42 36 pressed. By this press belt 42, the nonwoven fabric web and the roller 36 touching inner endless belt 40 are pressed against the roller 36.

Preferably, simultaneously with the mechanical pressurization of the nonwoven web by the press belt 42 of the belt press 34, a drying fluid is forced through the endless belts 40, 42 and the nonwoven web by creating a pressure differential between the roller 36 and the outer press belt 42 In order to make this possible, the endless belts 40, 42 in the present case are permeable to the drying fluid, ie permeable to the drying fluid. In addition, in this embodiment, the roller 36 of the belt press 34 is designed to discharge or receive the drying fluid having an open surface. It may in particular be formed by a suction or blowing roll. In addition, it is preferred that at least one endless belt 40, 42 looped around the drum of the belt press is permeable to water or adapted to receive water to absorb the water generated by the mechanical pressing occurring in the belt press 34 and / / or to be allowed to pass. In particular, air or water vapor can be used as the drying fluid, it being possible to use air at ambient temperature or also hot air as the drying air. In the case of a suction roll, the drying fluid, starting from a drying fluid hood 44, is sucked or guided at least through the permeable outer endless belt 42, the nonwoven material web and the permeable inner endless belt 40 into the suction roll. In the case of a blow roll, the drying fluid from the blow roll is blown into the hood 44 at least through the permeable inner endless belt 40, the nonwoven web, and the permeable outer endless belt 42.

As shown, the belt press 34 can be provided, for example, with only two endless belts 40, 42 wrapping the roller 36. The nonwoven material web lying between these endless belts 40, 42 is in this case touched by the two endless belts 40, 42.

In principle, however, the belt press 34 can also be provided, in addition to the inner and outer endless belts 40, 42, with at least one further endless belt which wraps around the roller 36 over a certain wrap angle. In this case, at least one such further endless belt can be arranged, for example, between the outer endless belt 42 and the nonwoven material web.

The endless belts 40, 42 wrapping the roller 36 of the belt press 34 preferably comprise at least one felt belt and / or at least one fabric belt. In this case, in particular as the roller 36 of the belt press 34 looping inner endless belt 40 may be provided a felt belt. If the nonwoven material web in the belt press 34 is additionally preferably accompanied by a drying fl uid. id acted upon, at least one felt belt is provided behind the nonwoven material web at least in the direction of flow of the drying fluid.

In particular, in the case that the nonwoven material web in the belt press 34, which is preferred, in addition to a drying fluid is applied, as already mentioned, all wrapped around the roller 36 of the belt press 34 endless belts 40, 42 for the drying fluid permeable or permeable. As an outer endless belt 42 of the belt press 34, for example, an at least substantially smooth belt, in particular smooth forming belt, can be used.

In certain cases, it is advantageous if at least one endless belt 40, 42 of the belt press 34 contacting the nonwoven material web is designed as a structured belt, by means of which the nonwoven material web is structured and / or perforated accordingly.

According to an expedient embodiment of the present invention, the endless belts 40, 42 wrapping the roller 36 of the belt press 34, in particular in the direction of flow of the drying fluid, comprise a permeable endless belt, an endless smooth forming fabric, an endless fabric belt and an endless felt belt. In principle, however, fewer or more endless belts and / or the endless belts may be provided in a different order than the one just mentioned.

If the roller 36 of the belt press 34 is designed as a suction roller, the belts wrapping the roller 36 preferably comprise, viewed in the direction of flow of the drying fluid a) a permeable press belt stretched around the roller 36, a permeable fabric belt and a permeable felt belt, or

b) a permeable press belt stretched around the roll 36, a permeable wire belt, a permeable fabric belt and a permeable felt belt, or c) a permeable press belt stretched around the roll 36, a permeable felt belt, a permeable fabric belt and a permeable felt belt, or d) a permeable felt press belt stretched around the roller 36, a permeable fabric belt and a permeable felt belt. On the other hand, if the roller 36 of the belt press 34 is designed as a blower roll, the belts wrapping the roller 36 preferably comprise viewed in the direction of flow of the drying fluid

a) a permeable press belt stretched around the roller 36, a permeable fabric belt and a permeable felt belt, or

b) a permeable press belt stretched around the roll 36, a permeable wire belt, a permeable fabric belt and a permeable felt belt, or c) a permeable press belt stretched around the roll 36, a permeable felt belt, a permeable fabric belt and a permeable felt belt, or d) a permeable felt press belt stretched around the roller 36, a permeable fabric belt and a permeable felt belt

The endless belts 40, 42 of the belt press can in particular be wound around the roller 36 over the same wrap angle. Downstream of the belt press 34, the nonwoven material web is guided by a TAD or air drying device 46 which comprises not more than one TAD throughflow cylinder or TAD drying cylinder (see also FIG. 3). The diameter of the drying cylinder of the TAD or air drying device is preferably less than 4 m, preferably less than 3.5 m and more preferably less than 3 m. The nonwoven fabric Material web are dried in such a thermal drying device in particular to the final dry content.

In the former 28, the nonwoven fabric may advantageously be formed with a low consistency having a solids content of in particular 0.01 to 0.1% on a smooth forming fabric or a structured forming fabric which structurally and / or perforates the nonwoven fabric. For this purpose, in particular a so-called Schrägsiebformer or the like can be used. The fleece can also be structured and / or perforated at the same time by the optionally provided hydroentanglement device 32. Such a hydroentanglement device 32 is accordingly preferred, in particular in those cases in which the nonwoven or the nonwoven material web is additionally to be structured and / or perforated.

In particular for producing a nonwoven material web having a basis weight of greater than 50 g / m ² , preferably greater than 80 g / m ² and particularly preferably greater than 100 g / m ² , the nonwoven material web before or after the belt press 34 be guided over a vacuum applied suction roll.

In detail, the schematic representation of the first exemplary embodiment of the inventive device 30 for producing nonwovens comprises a former 28, a hydroentanglement device 32, a belt press 34 and a thermal drying device 46, which is a TAD or Luftdrocknungseinrichtungseinrich- tion acts. In this case, this TAD drying unit preferably contains only a single drying cylinder or throughflow cylinder.

In the former 28, the nonwoven web is formed, for example, by the wet process with a low consistency on a forming fabric 48, which at the same time as Transfer belt for transferring the nonwoven to the hydroentanglement device 32 is used. As indicated at "50", the nonwoven fabric can be formed with an additional layer. The web formed in the former 28 is transferred to the hydroentangling apparatus 32 in a closed loop by the forming wire 48.

The consolidated nonwoven web 52 is transferred from the hydroentanglement device 32, for example, in an open draw to the belt press 34, which is shown here with only two endless belts 40, 42 wrapped around the roller 36, for example. From this belt press 34, the nonwoven material web 52 is transferred, for example, in an open train to the TAD drying device 46. Simultaneously with the mechanical pressurization of the nonwoven material web 52 by the belt press 34, a drying fluid is preferably pressed through the endless belts 40, 42 permeable in this case and through the nonwoven material web 52 by a corresponding pressure difference. In this case, the roller 36 has an open surface, wherein, as already mentioned, it can be embodied in particular as a suction or as a blower roll. In the illustrated embodiment, the hood 44 intended for dispensing or receiving the drying fluid is arranged above the roller 36. As shown, the roller 36 may be associated with a scraper 62. The hydroentanglement device 32 is not mandatory. However, it can be provided in particular in the case that the nonwoven material web 52 is additionally structured and / or perforated. Such structuring or perforation can take place, inter alia, via the hydroentanglement device 32. In addition, in particular, the belt press 34 can also be provided with at least one structuring and / or perforating the nonwoven material web 52. be provided with the structural band, which is again wrapped around the roller 36.

FIG. 3 shows a schematic representation of a further exemplary embodiment of the device according to the invention with an additional suction roll 56 connected upstream of the belt press 34 and an additional dewatering press 58 connected downstream of the belt press.

The respective device 30 for the production of nonwovens again comprises a former 28, a belt press 34 and no more than one TAD or air drying device 46.

The former 28 in the present case is, for example, a wet-method former for forming a non-woven web. In addition, it is also possible again to provide a hydroentanglement device 32 which, as mentioned, however, is not mandatory.

In front of the belt press 34, the consolidated nonwoven material web is guided, together with a flat forming fabric 54 structured for structuring and / or perforating the nonwoven material web, and the outer endless belt 42 of the belt press 34, around an additional suction roll 56 and in its region against the inner endless belt Pass 40 of the belt press 34. The additional suction roll 56, like the hydroentangling device 32, is not mandatory.

The outer endless belt 42 of the belt press 34 again serves as a press belt 42 over which the inner endless belt 40 and the nonwoven web lying between it and the outer endless belt 44 are pressed against the roller 36 of the belt press 34. Simultaneously with the mechanical pressure loading of the nonwoven material web by the belt press 34 is preferred by a corresponding pressure difference again pressed a drying fluid through the endless belts 40, 42 and the intermediate nonwoven material web. At least in this case, the endless belts 40, 42 looped around the roller 36 of the belt press 34 are permeable or permeable to the drying fluid. The roller 36 is again designed with an open surface, wherein it may in particular be formed again by a suction or blower roll.

In the present case, the dehumidifying or receiving hood 44 is disposed below the roller 36. As also already mentioned, the drying fluid may in particular be air or steam. In the former case, air with ambient temperature or even hot air can be used. The inner endless belt 40 of the belt press 34 can be designed in particular as a felt belt. Following the belt press 34 may additionally be provided a dewatering press 58, which is designed in the present case as a roller press. However, such an additional dewatering press 58 is also not mandatory. As can be seen from Fig. 3, the nonwoven web in the present case on one and the same Formiersieb 54 starting from the former 28 to the additional suction roll 56, the roller 36 of the belt press 34, through the additional dewatering press 58 and to thermal dewatering device 46 out. At the same time, the forming belt 54 acting as a transfer belt is arranged in the region of the belt press 34 between the inner endless belt 40 and the outer endless belt 42 of the belt press 34, wherein the nonwoven material web in the extended press nip 38 of the belt press 34 between the inner endless belt 40 and the Formierieb 54 comes to rest. In the press nip of the additional dewatering press 58 is the nonwoven material web between the inner endless belt 40 of the belt press 34 and the same time as The nonwoven material web is then transferred to the drying cylinder 60 of the forming belt 54 via the forming fabric 54, which is not more than a thermal TAD or air drying device 46. The forming fabric 54, which simultaneously serves as a transfer belt, can be designed to be flat or to structure and / or perforate the nonwoven material web as a structural band. The hydroentanglement unit 32 is particularly preferable in the case where patterning or perforation of the nonwoven fabric web is intended. Incidentally, this hydroentanglement device 32 as well as the additional suction roller 56 and the additional dewatering press 58 are purely optional.

The forming fabric 54, which also serves as a transfer belt, is also permeable, ie permeable to the drying fluid which optionally additionally impinges the nonwoven material web in the belt press 34. This drying fluid thus flows in the belt press 34 optionally both through the two endless belts 40, 42 of the belt press 34 and the nonwoven material web and through the forming fabric 54. The direction of the drying flow depends on whether the roller 36 of the belt press 34 is functioning as Suction roll or is designed as a blower roll. In the present exemplary embodiment according to FIG. 3, the drying fluid-absorbing hood 44 is arranged below the roller 36 of the belt press 34, for example. In the present case, after the nonwoven fabric is formed on the forming fabric 54 and passed through this sieve 54, which at the same time serves as a transfer belt, over the suction roll 56, through the belt press 34 and through the additional dewatering press 58 to the thermal drying device 46, this results in an overall extremely compact construction , 4 shows a schematic representation of another exemplary embodiment of a belt press 34 of the device according to the invention.

In the present case, the hood 44 is arranged above the roller 36 of the belt press 34 for dispensing or receiving the drying fluid. In addition, in the illustrated exemplary embodiment only an inner endless belt 40 and serving as a press belt 42 outer endless belt 42 is wound around the roller 36 of the belt press 34. The loop of the inner endless belt 40 is arranged in the present case below the loop of serving as a press belt outer endless belt 42. The inner endless belt 40 may in particular be a felt belt again. The drying fluid flow is directed from top to bottom or from bottom to top, depending on whether the roller 36 is designed as a suction roller or as a blow roller. The nonwoven web of material to be dewaxed lies again between the inner endless belt 40 and the outer endless belt 42. As already mentioned, the additional loading of the nonwoven web with drying fluid is optional. It is particularly preferred when the

Nonwoven material web should be structured and / or perforated simultaneously.

Also in the present embodiment shown in FIG. 4, a scraper 62 assigned to the roller 36 of the belt press 34 can again be seen. As can be seen in particular Figs. 3 and 4, the respective endless belts 40, 42 are guided in the same wrap around the roller 36 of the belt press 34, wherein the wrap angle is expediently slightly larger than the suction or blowing zone 64 of the roller of the belt press 34 , LIST OF REFERENCES

10 conventional device

12 shaper

14 hydroentanglement device

16 intake manifold, suction box

18 drainage device

20 TAD drying device

22 dipping bath

24 winding device

26 forming fabric

28 shaper

30 device

32 hydroentanglement device

34 belt press

36 roller

38 extended press nip or press nip

40 inner (endless) band

42 outer (endless) band

44 (drying) hood

46 TAD drying device

48 forming fabric

50 additional shift

52 nonwoven material web

54 forming fabric

56 suction roll

58 drainage press

60 flow-through cylinder / drying cylinder

62 scrapers

64 suction or blowing zone

Claims

claims

A process for the production of a nonwoven fabric in which a nonwoven fabric is formed in a former (28) and the resulting nonwoven material web (52) is subsequently further dehydrated, the further dewatering of the nonwoven material web (52) by means of a belt press ( 34), said belt press (34) comprising a roller (36) around which at least one inner band (40) adjacent to said roller (36) and an outer press belt (42) are wound, said nonwoven material web (52 ) is arranged at least in the region of the roller (36) between the inner band (40) and the outer press belt (42), wherein the press belt (42) is pressed against the roller (36) with a belt tension of at least 15 kN / m and thereby the nonwoven web (52) and the inner web (40) are pressed against the roll (36), and wherein the nonwoven web (52) after the belt press (34) is TAD ("through air drying") or air drying device (46), which not more than one TAD cylinder (60) is guided to bring the nonwoven web (52) to the final dry content.

Method according to claim 1,

characterized in that the diameter of the flow-through cylinder (60) of the TAD device (46) is less than 4 m, preferably less than 3.5 m, and more preferably less than 3 m. Method according to claim 1 or 2,

characterized in that as bands (40, 42) of the belt press (34) against drying fluid and preferably against air and / or water vapor permeable belts (40, 42) are used and simultaneously with the pressing of the nonwoven material web (52) against the roller (36) pressing a drying fluid through the permeable belts (40, 42) and the nonwoven web (52), preferably by creating a corresponding pressure differential between the roller (36) and the outer press belt (42), the roller (36) of the belt press (34) is designed to discharge or receive the drying fluid having an open surface.

Method according to claim 3,

characterized in that by the belts (40, 42) a drying fluid flow in a range of 100 m ³ / (min m ² ) to 300 m ³ / (min m ² ) and preferably from 150 to 250 m ³ / (min m ² ) is produced.

Method according to at least one of the preceding claims, characterized in that the outer press belt (42) with a belt tension of 20 to 100 kN / m, preferably from 25 to 75 kN / m and particularly preferably from 40 to 50 kN / m to the roll (36) of the belt press (34) is pressed.

Method according to at least one of the preceding claims, characterized in that a mechanical pressure of less than 140 kPa, preferably less than 100 kPa and particularly preferably less than 90 kPa, is exerted on the nonwoven material web (52) in the belt press (34) becomes. Method according to at least one of the preceding claims, characterized in that at least one band (40, 42) of the belt press (34) contacting the nonwoven material web (52) is provided as a structured band, through which the nonwoven material web (52) correspondingly structured and / or perforated.

Method according to at least one of the preceding claims, characterized in that the roller (36) of the belt press (34) is designed as a suction roller and the belts (36) wrapped around the roller (36) in the direction of flow of the drying fluid a) a tensioned around the roller (36) b) comprises a permeable pressing belt (42) stretched around the roller (36), a permeable sieve belt, a permeable cloth belt and a permeable felt belt, or permeable felt belt (42);

c) comprise a permeable press belt (42) stretched around the roller (36), a permeable felt belt, a permeable fabric belt and a permeable felt belt, or

d) comprise a permeable felt press belt stretched around the roller (36), a permeable cloth belt and a permeable felt belt.

Method according to at least one of claims 1 to 7,

characterized in that the roller (36) of the belt press (34) is designed as a blow roller and the belts (36) wrap around the roller against the flow direction of the drying fluid

a) comprise a permeable press belt (42) stretched around the roller (36), a permeable fabric belt and a permeable felt belt, or b) comprise a permeable press belt (42) stretched around the roller (36), a permeable screen belt, a permeable fabric belt and a permeable felt belt, or

d) comprise a permeable felt press belt stretched around the roller (36), a permeable cloth belt and a permeable felt belt. 10. The method according to at least one of the preceding claims,

Thereby, prior to the transfer of the resulting nonwoven material web into the belt press (34), the formed web is consolidated by a consolidation process which preferably comprises mechanical consolidation and / or hydroentanglement.

Method according to claim 10,

In this way, the nonwoven is simultaneously structured and / or perforated during solidification, preferably by the application of water jet.

12. An apparatus for producing a nonwoven fabric, in particular for carrying out the method according to at least one of the preceding claims, comprising a former (28) for forming a nonwoven fabric and a belt press (34) for further dewatering of the nonwoven fabric produced from the formed nonwoven fabric. A material web (52), wherein the belt press (34) comprises a roller (36) around which at least one inner band (40) adjacent to the roller (36) and an outer press belt (42) are wound, wherein the nonwoven material web ( 52) at least in the region of the roller (36) between the inner band (40) and the press belt (42) can be arranged and preferably wherein the press belt (42) is pressable and preferably pressed to the roller (36) with a belt tension of at least 15 kN / m, and wherein downstream of the belt press (34) a TAD ("through air drying") is provided. Air drying device (46), which comprises no more than one TAD or flow through cylinder (60), is provided.

13. Device according to claim 12,

Thus, the diameter of the drying cylinder (60) of the TAD or air drying device (46) is less than 4 m, preferably less than 3.5 m and particularly preferably less than 3 m.

14. Device according to claim 12 or 13,

Thereby, the belts (40, 42) of the belt press (34) are compared with drying fluid and preferably opposite

Air and / or water vapor permeable belts (40, 42) are formed so that simultaneously with the pressing of the nonwoven material web (52) against the roller (36) by a pressure difference between the roller (36) and the outer press belt (42) a drying fluid may be flowed through the permeable belts (40, 42) and the nonwoven web (52), wherein the roller (36) of the belt press (34) is configured to discharge or receive the drying fluid having an open surface. 15. Device according to at least one of claims 12 to 14,

By doing so, that is

between the former (28) and the belt press (34) is arranged a device (32) for solidifying the formed web to a nonwoven material web, wherein the device (32) is a hydroentanglement device (32).