Installation and method for producing a single-layer or multilayer web

Abstract

The invention relates to a system and a method for producing a nonwoven, the system comprising a device for producing a layer of wet-laid fibers, downstream of which device, in the material transport direction, a bonding device and at least one dryer are disposed, characterized in that the device for producing the wet-laid fibers is in the form of a cylinder-mold former.

Description

[0001] Title: Plant and process for the production of a single- or multi-layer nonwoven fabric

[0002] Description

[0003] The invention relates to a system and a method for producing a single- or multi-layer nonwoven fabric according to the preamble of claims 1, 2, 6 and 20.

[0004] According to the prior art, it is known to arrange a loose layer of fibers, such as pulp, between two carded nonwovens and to bond them together using water jets. A system and a process of this type are described, for example, in EP 0992338 B1. The loose layer of fibers can be produced and deposited using wet lay-up, meltblown, or airlaid processes. A disadvantage is the low strength of the multilayered nonwoven, which, after water jet bonding, relies almost exclusively on the strength of the carded nonwoven. Another disadvantage of the airlaid process is that fibers of different lengths or compositions cannot be processed.

[0005] Applying short fibers using airlaid has the disadvantage that the short fibers can only be jet-needled with increased effort, e.g., using a binder, making it difficult to produce a biodegradable product. Using an inclined screen to produce a wet-laid layer of short fibers requires a lot of installation space, high water consumption, and is very expensive in terms of investment costs.

[0006] Accordingly, the invention is based on the objective of further developing a system and a process for producing a single- or multi-layer nonwoven fabric in such a way that the system can be designed to save space and be operated cost-effectively. Furthermore, the system should be designed to produce a single- or multi-layer nonwoven fabric that is preferably biodegradable.

[0007] The invention is solved by the features of claims 1, 2, 6, and 20. The inventive system for producing a multilayer nonwoven fabric comprises at least one device for producing and / or depositing a first nonwoven fabric onto a circulating belt, wherein, downstream in the material transport direction, a device is arranged which is configured to apply a layer of wet-laid fibers to the first nonwoven fabric. Downstream in the material transport direction, a device for consolidating and / or bonding the first nonwoven fabric with the layer of wet-laid fibers is provided, wherein the distance I between the depositing points of the first nonwoven fabric on the circulating belt and the depositing point of the layer of wet-laid fibers on the first nonwoven fabric is a maximum of 10 m. The inventive system has a very compact design and can be acquired and operated with low investment and operating costs.

[0008] In a three-layer nonwoven fabric, the system comprises at least one device for producing and / or depositing a first nonwoven fabric onto a circulating belt, with a further device for producing and / or depositing a further nonwoven fabric onto a circulating belt arranged downstream in the material transport direction. Between these two devices is a device for producing a layer of wet-laid fibers, which are deposited between the first and the further nonwoven fabrics on a circulating belt. According to the invention, the distance L between the depositing point of the first nonwoven fabric on the circulating belt and the depositing point of the second nonwoven fabric on the layer of wet-laid fibers is a maximum of 25 m. Preferably, the devices for producing the first nonwoven fabric and / or the second nonwoven fabric are designed as carding machines, wherein the nonwoven fabrics from the carding machines can be applied to the circulating belt and / or to the layer of wet-laid fibers.

[0009] Alternatively, the devices for producing the first nonwoven and / or the second nonwoven can be designed as a spunbond nonwoven plant, wherein the nonwovens made of continuous fibers can be applied to the circulating belt and / or to the layer of wet-laid fibers.

[0010] In an alternative embodiment, a device for producing the first nonwoven and / or the second nonwoven is designed as an unwinding station that can apply the nonwoven to the circulating belt and / or to the layer of wet-laid fibers. The nonwoven from the unwinding stations can consist of carded nonwovens, prefabricated nonwovens of any fiber blend, nonwovens made of continuous filaments, or nonwovens made of staple fibers.

[0011] Likewise, any combination of the device for producing a layer of wet-laid fibers with a carding machine, an unwinding station and / or a spunbond nonwoven machine is possible.

[0012] Preferably, the device for producing the wet-laid fibers is designed as a rotary screen former, which can be integrated as a compact unit between one or two carding machines and / or between one or two spunbond nonwovens and / or between one or two unwinding stations, or can consist of a combination of these three variants. This results in a very short overall length for the system, which can also be retrofitted into existing systems. In particular, with an underfloor rotary screen former, the installation space can be further reduced, as the interfaces of the circulating belts for transferring the wet-laid fibers and / or nonwovens are easy to implement.

[0013] According to a further aspect of the invention, the inventive system for producing a nonwoven fabric comprises a device for producing a layer of wet-laid fibers, to which a consolidation device and at least one dryer are arranged downstream in the material transport direction. The invention is characterized in that the device for producing the wet-laid fibers is designed as a rotary screen former. The rotary screen former has the advantage that the layer of wet-laid fibers can be produced with a very compact installation space and has two smoothed sides (top and bottom). No further downstream belts, rollers, or smoothing devices outside the rotary screen former are necessary, so that the layer of wet-laid fibers can be consolidated and further processed alone or in combination with one or more nonwovens. The distribution of the fibers is particularly advantageous at low basis weights of 10 to 50 g / m². 2The coverage is very uniform over a width of up to 5 m, which cannot be achieved with an airlaid system.

[0014] In contrast to the classic inclined screen former, the use of the rotary screen former offers the advantage of being more compact and inexpensive, consuming less water, and making the entire system with pumps, piping, etc., smaller and more compact, and thus significantly cheaper to operate.

[0015] Compared to an airlaid system, the rotary screen former offers the advantage that the wet-laid fibers can be processed with two smooth, even surfaces. These surfaces are smoothed by the cylinder on the underside and, for example, by a belt, a scraper, or a roller on the top side of the wet-laid fibers. Due to these smoothed surfaces, a very uniform material distribution and basis weight are achieved, particularly with light and thin wet-laid fibers, which cannot be achieved with other processes (airlaid, meltblown). The rotary screen former is especially advantageous for thin and light layers of wet-laid fibers with a basis weight of 10 to 50 g / m². 2where uneven thickness has a particularly strong impact. Especially with pulp fibers, this level of uniformity cannot be achieved with an airlaid system. Another advantage of the rotary screen former over airlaid or meltblown systems is the wide variety of fibers and fiber blends that can be processed in terms of length and fiber type. This is particularly advantageous for the production of biodegradable nonwovens, which cannot be processed with an airlaid system.

[0016] According to the inventive method for producing a nonwoven fabric, a

[0017] A fiber suspension is deposited on a rotating cylinder designed to draw off at least some of the liquid from the fiber suspension, creating a layer of wet-laid fibers. This layer is captured on the top side by a circulating belt and transferred to another circulating belt, where it is compacted and dried. The inventive method produces a very thin and lightweight layer of wet-laid fibers that is particularly uniform in terms of basis weight and material distribution, since both sides (top and bottom) are smoothed during the manufacturing process as they emerge from the rotary screen former. The layer of wet-laid fibers can be compacted and / or dried without further processing, either alone or in combination with one or more nonwovens.The process is particularly suitable for very short fibers (1 to 3 mm, preferably 1 to 12 mm average fiber length) that are biodegradable. Using the process according to the invention, thin layers of wet-laid fibers with a width of up to 5 m, exhibiting a very uniform basis weight, can be produced at a speed of up to 400 m / min.

[0018] Further measures improving the invention are described in more detail below together with a description of a preferred embodiment of the invention with reference to the figures.

[0019] Figure 1 shows a first embodiment of a system according to the invention; Figure 2 shows an enlarged view of the rotary screen former; Figure 2a shows an enlarged view of the cylinder of a rotary screen former; Figure 3 shows a further embodiment of a system according to the invention; Figure 4 shows a further embodiment of a system according to the invention; Figure 5 shows a further embodiment of a rotary screen former; Figure 6 shows a further embodiment of a rotary screen former; Figure 7 shows a further embodiment of a rotary screen former.

[0020] Figure 1 shows a system 1 in which a first carding unit 2 lays a carded nonwoven fabric 2a onto a circulating belt 3. The carded nonwoven fabric 2a can consist of viscose fibers with, for example, a density of 1.7 denier and a fiber length of 40 mm. A rotary former 20 is arranged downstream, configured to produce a layer of wet-laid fibers 24. A further carding unit 6, also configured to produce a carded nonwoven fabric 6a, can be arranged downstream of the rotary former 20 in the transport direction. At least one water jet bonder 7 and a dryer 9 are arranged downstream in the transport direction. The system 1 is configured to produce variably only a layer of wet-laid fibers 24, a nonwoven fabric 2a with a layer of wet-laid fibers 24, or a nonwoven fabric 2a with a layer of wet-laid fibers 24 and a further nonwoven fabric 6a.

[0021] A rotary screen former 20 produces a layer of wet-laid fibers 24 and deposits them onto a circulating belt 3. For this purpose, the rotary screen former 20 has a headbox 23 through which a fiber suspension, for example of pulp, is deposited via a line onto a driven rotating cylinder 22. Preferably, the rotating cylinder can

[0022] 22 has a perforated jacket with a multitude of holes, which can be suctioned from the inside. By means of a stationary suction device in the rotating cylinder 22, the

[0023] The majority of the water is removed from the fiber suspension. The wet fibers 24, deposited on the cylinder 22, are transported away with their upper surface facing down by a circulating belt 21, which is preferably designed as a screen belt. The upper surface of the wet fibers 24 is held and transported away by one side of the belt 21, which in this embodiment is directed downwards and thus uses gravity to deposit the wet fibers 24 onto the circulating belt 3. This produces a single-layer nonwoven fabric, which can be compacted, dried, and wound up for further processing. Preferably, the layer of wet-laid fibers 24 can be treated with a binder before compaction.

[0024] Preferably, the system 1 comprises at least one device for producing a carded nonwoven fabric, which is arranged upstream of the rotary screen former 20 in the transport direction. The device can be designed as a carding unit 2. In this case, the layer of wet-laid fibers 24 is deposited onto the nonwoven fabric 2a by the carding unit 2. This produces a two-layer nonwoven fabric comprising a layer of carded nonwoven fabric 2a and a layer of wet-laid fibers 24, which are bonded together, dried, and further processed as a nonwoven fabric 10 or wound up by means of a winder 11.

[0025] Optionally, the wet-laid fibers 24 can be covered by another carded nonwoven 6a via a further carding unit 6, so that the wet-laid fibers 24 are compartmentalized on both sides by a nonwoven 2a, 6a. The carded nonwoven 6a can also consist, for example, of viscose with a density of 1.7 denier and a fiber length of 40 mm. The three layers can subsequently be bonded together, dried, and further processed as a nonwoven 10 or wound up using a winder 11. The illustration of the carding unit 6 above the rotary screen former is only schematic. In reality, the system components 2, 20, and 6 are arranged downstream in the transport direction. The illustration of the depositing of the nonwovens 2a, 6a onto one or more circulating belts 3 is also only schematic. Typically, the carded nonwovens are deposited from the carding unit at a slight angle from above the conveyor belt(s).The circulating belt 3 described in the invention does not limit the number of circulating belts used to process the wet-laid fibers 24 and / or carded nonwovens 2a, 6a. Multiple circulating belts can also be used. In all three variants, the water jet bonding 7 can be operated in one or more stages at a pressure of 40–400 bar, with a suction device 8 being arranged below the circulating belt 3 for extracting the water from the water jet bonding 7. The bonded multilayer nonwoven then passes through a dryer 9, which can be designed as a drum dryer or a belt dryer. After drying, the single- or multilayer nonwoven 10 can be wound onto a winder 11.An advantage of the system 1 according to the invention lies in the small space requirement for the production of a single- or multi-layer nonwoven fabric, the uniform distribution of the wet-laid fibers 24 across the width of the resulting nonwoven fabric, as well as in the possible use of secondary fibers, regenerated fibers and / or recycled fibers, so that a biodegradable nonwoven fabric can be produced. A further advantage is that the system can be operated with only one layer of wet-laid fibers 24, or with two layers (2a and 24) or (24 and 6a) or with three layers (2a and 24 and 6a) of fibers or nonwoven fabrics, and is very economical to operate due to its compact design and low investment costs.

[0026] The distance L between the support points where the nonwovens 2a and 6a are placed on one or more belts 3, and between which the layer of wet-laid fibers 24 is applied, is a maximum of 25 m. The distance I between the support point of a nonwoven 2a on one or more belts 3 and the point following in the transport direction where the wet-laid fibers 24 are applied to the nonwoven 2a is a maximum of 10 m. This creates a short and compact system that cannot be achieved using a conventional inclined screen former.

[0027] Figure 2 shows an enlarged view of a first embodiment of the rotary sieve former.

[0028] 20, in which a fibrous suspension is deposited onto a driven rotating cylinder 22 by means of a headbox 23. The cylinder 22 may preferably be perforated

[0029] The cylinder 22 has a jacket and can drain the water from the fiber suspension through it. For this purpose, the entire cylinder can be under slight negative pressure and have a drain for the drained water.

[0030] Contain water. Additionally, the cylinder 22 can also be suctioned, at least in the partial area on its circumference where the belt 21 rests, which in the embodiment of the

[0031] Figure 2a describes this in more detail. Alternatively, a suction port (not shown) can be located above the

[0032] cylinder 22 are arranged, which the water of the fiber suspension passes through the circulating

[0033] Extraction from band 21. Preferably, the extraction can be carried out inside and / or outside the

[0034] The thickness of cylinder 22 can be varied segment by segment over a partial circumference. Cylinder 22 or the surrounding band 21 can be fitted with one or more (not shown)

[0035] Couch rollers work together to further dewater and compact the wetted fibers 24. The circulating belt 21, which can be designed as a screen belt, is guided around several deflection rollers 28 and rests with one outer side on a

[0036] Partial circumference of cylinder 22 is tensioned so that the water flows out of the

[0037] A fibrous suspension is pressed. At least one deflection roller 28 can be designed as a tension roller with which the circulating belt 21 can be tensioned. The cylinder 22 and the belt 21 preferably rotate or move at the same speed.

[0038] The pickup 25 can be arranged on the inner side of the belt 21 in the area where the belt 21 detaches from the cylinder 22. The pickup 25 can be designed as a suction chamber, so that a vacuum forces the fibers 24 onto the belt 21 and removes them from the cylinder 22. The fibers 24 are thus transported upside down, with their upper side facing down, from the belt 21 towards the circulating belt 3, on which the nonwoven fabric 2a can then rest. In the area where the fibers 24 are transferred to the nonwoven fabric 2a, a separating suction device 26 can be arranged on the rotary screen former 20, with which the fibers are separated from the belt 21 by means of suction air. The separating suction device 26 is arranged below the circulating belt 3 and can – if present – ​​simultaneously allow air to flow through the nonwoven fabric 2a.On the opposite side of the tape 21, i.e., on the inside of the tape 21, a pressure device 27 can be arranged to reinforce the detachment effect of the fibers 24 from the tape 21. This device uses air or water pressure to detach the fibers 24 from the tape 21. Preferably, a deflection roller 28a is designed to be adjustable in position so that an open angle is created in the transfer area of ​​the wetted fibers 24 onto the nonwoven fabric 2a between the tapes 3 and 21 in the transport direction. This angle assists the detachment of the wetted fibers 24 from the tape 21.

[0039] The quality of the wet-laid fibers 24 can be optimized at the headbox 23 by controlling the dilution water, which further homogenizes the cross-sectional profile of the wet-laid fibers 24. With a working width of up to 5 m, this can result in a more uniform cross-section, especially with thin and light layers of wet-laid fibers. Further improvement can be achieved by heating the headbox, which also further enhances the cross-sectional profile of the wet-laid fibers 24. Edge extraction can be used to create sharper edges on the wet-laid fibers.

[0040] The rotary screen former 20 is mounted on a frame 29, which can optionally be arranged in the area of ​​a feed for further fibers or a nonwoven fabric 2a above a belt 3. Depending on the embodiment of the rotary screen former, with a modified belt guide, the layer of wetted fibers can also be laid down with its underside onto another conveyor belt that follows the circulating belt 21.

[0041] In the embodiment shown in Figure 2a, the cylinder 22 is suctioned at least in a partial area around its circumference, where the wetted fibers 24 are transferred from the headbox 23 to the rotating cylinder and then taken up by the belt 21. In this embodiment, the suction system 22a is stationary within the cylinder 22 and is designed in multiple stages, which may include a central suction port and two suction ports with reduced suction capacity arranged on either side. The cylinder 22 thus rotates around the stationary suction port 22a. Alternatives are possible, for example, a staged suction system that can decrease continuously or in stages around the circumference of the cylinder from the headbox 23 to the transfer point at the belt 21. A couch roller 30 above the belt 21 compacts the wetted fibers 24 and increases the dryness of the fibers 24.Alternatively, instead of the couch roller 30, a suction device (not shown in detail) can be arranged overhead above the belt 21 in the area where the wetted fibers 24 are transferred from the cylinder 22 to the belt 21.

[0042] Figure 3 shows an alternative embodiment in which, instead of the carding heads 2 and / or 6 from Figure 1, one or two nonwovens 12a, 14a can be unwound from a separate unwinding station 12, 14 via a deflection roller 13, 15 and fed into the system 1. For example, the nonwoven 12a, 14a can each have a basis weight of 15 g / m². 2 exhibiting a pulp quantity of 20 g / m³. 2 , which is processed by the rotary screen former 20, results after the dryer 9 in a light multilayered fleece 10 with a total weight of 50 g / m² 2The nonwoven fabric 10 can preferably be used as a biodegradable product for the hygiene or cosmetics sector. Alternatively, the fibers of the nonwoven fabric 12a, 14a can also consist of lyocell, cotton, flax, or other renewable raw materials. In particular, the use of secondary fibers, regenerated fibers, or recycled fibers expands the application range of the system 1 for the production of a biodegradable nonwoven fabric that cannot be achieved with an airlaid or meltblown system. In this embodiment as well, the distance L between the support points where the nonwoven fabrics 12a and 14a are laid on one or more belts 3 and between which the layer of wet-laid fibers 24 is applied is a maximum of 25 m.The distance I between the support point of a nonwoven fabric 12a on one or more belts 3 and the subsequent support point in the transport direction, where the wet-laid fibers 24 are placed on the nonwoven fabric 12a, is a maximum of 10 m. This creates a short and compact system that cannot be achieved using a conventional inclined screen former. A further advantage is that the system can be operated with just one layer of wet-laid fibers 24, or with two layers (12a and 24) or (24 and 14a), or with three layers (12a and 24 and 14a) of fibers or nonwoven fabrics, and its compact design and low investment costs make it very economical to operate.

[0043] The use of the rotary sieve former 20 offers, in contrast to the airlaid process, the

[0044] The advantage is that the wet-laid fibers 24 can be further processed with two smooth or flat surfaces, which are formed by the cylinder 22 on the underside and by the

[0045] Band 21 is smoothed on the upper surface of the wet-laid fibers 24. Due to the smoothed surfaces, a uniform material distribution or a uniform basis weight is achieved, particularly with light and thin wet-laid fibers, which cannot be achieved with other processes (airlaid, meltblown). The advantage of the rotary screen former 20 over the classic inclined screen former lies in its compactness and low investment and operating costs. The alternative embodiment of the system according to Figure 4 shows a further alternative embodiment in which, instead of the carding units 2 and / or 6 from Figure 1 and / or the unwinding stations 12 and / or 14 from Figure 3, at least one nonwoven 16a or 17a made of synthetic continuous filaments can be drawn off from at least one spunlace machine 16, 17 or spunlace tower and fed into the system 1. For example, the nonwoven 16a, 17a can each have a basis weight of 15 g / m². 2exhibiting a pulp quantity of 20 g / m³. 2 , which is processed by the rotary screen former 20, results after the dryer 9 in a light multilayered fleece 10 with a total weight of 50 g / m² 2The nonwoven fabric 10, with its layer of wet-laid fibers 24 made from pulp, exhibits a high water retention capacity and is therefore preferably used in the hygiene or cosmetics sector. In this embodiment as well, the distance L between the support points where the nonwoven fabrics 16a and 17a are placed on one or more belts 3 and between which the layer of wet-laid fibers 24 is applied, is a maximum of 25 m. The distance I between the support point of a nonwoven fabric 16a on one or more belts 3 and the subsequent support point in the transport direction, where the wet-laid fibers 24 are applied to the nonwoven fabric 16a, is a maximum of 10 m. This results in a short and compact system that cannot be achieved using a conventional inclined screen former.Another advantage is that the system can be operated with just one layer of wet-laid fibers 24, or with two layers (16a and 24) or (24 and 17a) or with three layers (16a and 24 and 17a) of fibers or nonwovens and is very inexpensive to operate due to its compactness and low investment costs.

[0046] The embodiment shown in Figure 5 differs from that shown in Figure 2 in that the couch roller 30 is positioned in the transport direction upstream of the take-up unit, so that compaction and dewatering occur before the take-up unit 25, which transfers the wetted fibers 24 from the cylinder to the belt 21. A suction device 31 is also arranged upstream of the couch roller 30, which allows water to be extracted from the fiber suspension regardless of the design of the cylinder 22 (internally drawn or not). The pivotable arrangement of the deflection roller 28a allows an angle to be set between the belt 21 and the belt 3, which facilitates the transfer of the wetted fibers 24 to the nonwoven fabric 2a or directly onto the circulating belt 3. The tension of the belt 21 can also be adjusted via the deflection roller 28a.

[0047] The embodiments of the rotary screen former 20 according to Figures 1 to 6 are particularly advantageous for integration between two carding machines 2, 6, or between two unwinding stations 12, 14, or between two spunbond nonwoven machines 16, 17, or in any combination of the machine components (carding machine, unwinding station, spunbond nonwoven machine), where a small footprint is advantageous. A nonwoven fabric 2a, 12a, 16a can be passed below the rotary screen former 20, and the wet-laid fibers 24 of the rotary screen former 20 can be deposited onto this nonwoven fabric 2a, 12a, 16a.

[0048] Figure 6 shows an alternative embodiment of a rotary sieve former 20 with a different

[0049] Viewing direction or side view, in which band 3 with fleece 2a from right to left

[0050] (direction of transport) is transported. This embodiment is very compact, since the

[0051] Band 21 of the rotary sieve former 20 is predominantly arranged vertically.

[0052] Fibre suspension is fed onto a driven rotating cylinder by means of a headbox 23.

[0053] 22. The cylinder 22 may preferably have a perforated jacket and drain the water from the fiber suspension through it. For this purpose, the entire cylinder 22 may be under slight negative pressure and have a drain for the drained water.

[0054] Additionally, the cylinder 22 can also be suctioned, at least in the portion of its circumference on which the belt 21 rests. The circulating belt 21, which can be designed as a sieve belt, is guided around several deflection rollers 28 and rests with its outer side under tension on a portion of the circumference of the cylinder 22, so that the water is drawn out of the

[0055] The fibrous suspension is pressed. A suction device 31 in the form of a spout suction device draws off at least part of the liquid through the surrounding belt 21. Instead of a

[0056] The couch roller from Figure 5 transports the strip 21 with the wetted fibers 24 from an upside-down position to an inclined position by means of a deflecting roller 28. The deflecting roller 28 can be designed by means of an adjusting device such that in

[0057] The area of ​​deflection of the wetted fibers simultaneously results in compaction and further

[0058] Drainage takes place. At least one deflection roller 28a can be designed as a tensioning roller, with which the circulating belt 21 can be tensioned. The cylinder 22 and the belt

[0059] The rollers 21 rotate or move preferably at the same speed. The fibers 24 are thus transported upside down with their upper side facing the belt 21 towards a deflection roller 28, so that the wetted fibers 24 are rotated almost 180° upwards with their underside facing upwards. By means of another deflection roller 28, the fibers 24 are transported almost vertically downwards and in the area of ​​an adjustable or pivotable deflection roller.

[0060] 28a is deposited on a circulating belt 3 or a nonwoven fabric 2a, 12a. The nonwoven fabric 2a, 12a can be completely guided under the frame 29 of the rotary screen former 20 by a belt 3. In the area where the fibers 24 are transferred to the nonwoven fabric 2a, a separating suction device 26 is arranged on the rotary screen former 20, with which the fibers are separated from the belt 21. The separating suction device 26 is arranged below the circulating belt 3 and can simultaneously allow flow through the nonwoven fabric 2a, 12a. On the opposite side of the belt 21, i.e., on the inside of the belt 21, a pressure device 27 can be arranged to reinforce the separation effect of the fibers 24 from the belt 21, which uses air or water pressure to separate the fibers 24 from the belt 21.Preferably, a deflection roller 28a is designed to be adjustable in position so that an open angle is created in the transfer area of ​​the wetted fibers 24 onto the nonwoven fabric 2a between the belts 3 and 21 in the transport direction, which assists the detachment of the wetted fibers 24 from the belt 21. The pivotability of the deflection roller 28a simultaneously facilitates the passage of the nonwoven fabric 2a, 12a, 16a under the rotary screen former.

[0061] Figure 7 shows another embodiment of a rotary screen former 20 from a different viewing direction or side view, in which the rotary screen former 20 is arranged in the transport direction of the wetted fibers 24 in front of a circulating belt 3. This arrangement is, by way of example, at least partially below ground level, so that the wetted fibers 24 produced by the rotary screen former 20 can be transported approximately horizontally onto a circulating belt 3. A fiber suspension is deposited onto a driven, rotating cylinder 22 by means of a headbox 23. The cylinder 22 preferably has a perforated shell and drains the water from the fiber suspension through it. For this purpose, the entire cylinder 22 can be under slight negative pressure and have a drain for the drained water. Additionally, the cylinder 22 can also be suctioned, at least in the portion of its circumference on which the belt 21 rests.The circulating belt 21, which may be designed as a sieve belt, is guided around several deflection rollers 28 and rests with its outer side on a partial circumference of the cylinder 22 under tension, so that the water is pressed out of the fiber suspension. A take-up device 25 and a subsequent suction device 31 are designed to remove the wetted fibers 24 from the cylinder 22 and hold them against the belt 21 with their upper side facing down. At least some of the liquid can be suctioned out through the circulating belt 21. Another deflection roller 28 is designed to redirect the belt 21 such that a further deflection roller of the circulating belt 3 causes slight compaction of the wetted fibers 24. In the transfer area of ​​the wetted fibers from the belt 21 to the circulating belt 3, a separating suction device 26 can be arranged, which deposits the wetted fibers 24 onto the belt 3 with their underside facing down.Preferably, a deflection roller 28a is designed to be adjustable in position so that an open angle is created in the transfer area of ​​the wet-laid fibers 24 onto the belt 3 between the belts 3 and 21 in the transport direction, which assists the detachment of the wet-laid fibers 24 from the belt 21. (Not shown) At least one nonwoven fabric 2a, 6a, 12a, 14a, 16a, 17a can be fed in the transport direction from below or above the belt 3 to be bonded to the wet-laid fibers 24 by means of water jet bonding.

[0062] All versions of the rotary screen former can be combined as needed to suit various applications. The rotary screen former 20 is designed for a basis weight of 10 to 50 g / m². 2Suitable. The working speed can range from 50 to 400 m / min. The maximum working width can be up to 5 m. The subsequent bonding of one layer of wet-laid fibers 24 or several layers of nonwoven fabric with the wet-laid fibers 24 for all applications shown in Figures 1 to 7 can be carried out with one or more beams of a water jet bonding system 7 at a pressure of 40 to 400 bar.

[0063] According to the invention, the wet-laid fiber layer can consist at least partially of short synthetic fibers with a fiber length of 1 to 3 mm, preferably 1 to 12 mm, such as polyester, polyamide, polypropylene, or polyolefin. Fiber blends of synthetic and natural fibers are also possible. Likewise, the wet-laid fiber layer can consist of 100% pulp or other natural fibers that have a high water retention capacity and are preferably biodegradable. The use of secondary fibers, recycled fibers, or regenerated fibers is advantageous for the production of biodegradable fibers.

[0064] The fiber suspension can consist of a mixture of fibers with a high pulp content and a smaller proportion of short synthetic fibers with a fiber length of 1 to 3 mm, preferably 1 to 12 mm, such as polyester, polyamide, polyolefin, polypropylene, viscose, or lyocell. The basis weight of the dried nonwoven fabric 10 can preferably be 20 to 70 g / m². 2 be.

[0065] Depending on the embodiment, the nonwoven fabric 12a, 14a can, for example, consist of polyester, viscose, a cotton blend, or a mixture of synthetic and / or natural fibers; for example, one or both nonwoven fabrics 12a, 14a can also be made of tissue or paper. Preferably, the basis weight of the nonwoven fabric 10 is between 20 and 70 g / m². 2 . The fibers of the nonwovens 12a, 14a can consist of short fibers, for example staple fibers with a length of 3 to 60 mm, or of synthetic continuous filaments.

[0066] According to the invention, a very compact and flexible system for producing a single- or multi-layer nonwoven fabric 10 is obtained, which can consist solely of the web of wet-laid fibers 24, or solely of the carded nonwoven fabric 2a with or without the carded nonwoven fabric 6a. Alternatively, the nonwoven fabric 10 can consist of two or more layers, for example, of the wet-laid fibers 24 with one or two nonwoven fabrics 2a, 6a from the cards 2 and / or 6, or of the wet-laid fibers 24 with the nonwoven fabrics 12a and / or 14a and / or a further nonwoven fabric 16a and / or 17a from a spunbond nonwoven fabric plant 16 and / or 17.

[0067] Reference sign

[0068] 1 Annex

[0069] 2 junk

[0070] 2a Fleece

[0071] Volume 3

[0072] 6 junk

[0073] 6a Fleece

[0074] 7 Water jet hardening

[0075] 8 Extraction

[0076] 9 T dryer

[0077] 10 multi-layered nonwoven fabric

[0078] 11 winders

[0079] 12 processing stations

[0080] 12a Fleece

[0081] 13 Pulley

[0082] 14 processing station

[0083] 14a Fleece

[0084] 15 pulley

[0085] 16 spunbond nonwovens plant

[0086] 16a Spunbond fleece

[0087] 17 Spunbond nonwovens plant

[0088] 17a Spunbond fleece

[0089] 20 round sieve formers

[0090] Volume 21

[0091] 22 cylinders

[0092] 22a Extraction

[0093] 23 Stockpile

[0094] 24 wet-laid fibers

[0095] 25 customers

[0096] 26 vacuum cleaners

[0097] 27 Printing device 28, 28a Deflection pulleys

[0098] 29 scaffolding

[0099] 30 Gautschwalze

[0100] 31 Extraction

[0101] Length

[0102] L Length

Claims

Patent claims 1. Plant for the production of a multi-layered nonwoven fabric, comprising at least one Device for producing and / or depositing a first nonwoven fabric on a circulating belt, wherein a device is arranged downstream in the material transport direction which is configured to apply a layer of wet-laid fibers to the first nonwoven fabric, wherein a device for consolidating and / or bonding the first nonwoven fabric with the layer of wet-laid fibers is arranged in the material transport direction, wherein the distance I between the depositing points of the first nonwoven fabric on the circulating belt and the depositing point of the layer of wet-laid fibers on the first nonwoven fabric is a maximum of 10 m.

2. Plant for the production of a multilayer nonwoven fabric, comprising at least one Device for producing and / or depositing a first nonwoven fabric on a circulating belt, wherein a further device for producing and / or depositing a further nonwoven fabric on a circulating belt is arranged downstream in the material transport direction, wherein a device for producing a layer of wet-laid fibers is arranged between the devices for producing and / or depositing the first and the second nonwoven fabric, which are deposited between the first and the further nonwoven fabric on a circulating belt, characterized in that the distance L between the depositing point of the first nonwoven fabric on the circulating belt The distance between the band and the point where the second fleece is laid on the layer of wet-laid fibers is a maximum of 25 m.

3. Plant for the production of a multilayer nonwoven fabric according to claim 1 or 2, characterized in that the device for the production of the first nonwoven fabric is designed as a carding machine, as an unwinding station or as a spunbond nonwoven fabric plant.

4. Plant for the production of a multilayer nonwoven fabric according to claim 1, characterized in that the device for the production of the second nonwoven fabric is designed as a carding machine, as an unwinding station or as a spunbond nonwoven fabric plant.

5. Plant for the production of a multilayer nonwoven fabric according to one of claims 1 or 1, characterized in that the device for producing the wet-laid The fibers are designed as a circular sieve former.

6. Plant for the production of a nonwoven fabric, wherein the plant comprises a device for the production of a layer of wet-laid fibers, to which a consolidation device and at least one dryer are arranged downstream in the material transport direction, thereby characterized in that the device for producing the wet-laid fibers is designed as a circular sieve former.

7. Plant for the production of a nonwoven fabric according to claim 6, characterized in that the circular screen former has a stock head which is designed to deposit a fibrous suspension onto a rotating cylinder.

8. Plant for the production of a nonwoven fabric according to claim 7, characterized in that the rotating cylinder has a suction device.

9. Plant for the production of a nonwoven fabric according to claim 7, characterized in that the rotary screen former has a circumferential belt which is designed to compact the fiber suspension on the cylinder, so that a layer of wet-laid Fibers are produced.

10. Plant for producing a nonwoven fabric according to any one of the preceding claims 6 to 9, characterized in that the cylinder or the circulating belt interacts with at least one couch roller and / or overhead suction system.

11. Plant for producing a nonwoven fabric according to any one of the preceding claims 9 to 10, characterized in that the circulating belt interacts with a pickup device in the area where the wet-laid fibers detach from the cylinder.

12. Plant for the production of a nonwoven fabric according to one of the preceding claims 6 to 11, characterized in that the wet-laid fibers are laid down on a circumferential belt of the plant, wherein in the area of ​​the transfer of the wet-laid The belt of the rotary screen former has a separating suction device and / or a pressure device.

13. Plant for the production of a nonwoven fabric according to one of the preceding claims 9 to 12, characterized in that the circumferential belt of the rotary screen former is supported around several deflection rollers, wherein in the area of ​​the transfer of the wetted Fibers are arranged on the circulating belt of the system, at least one deflection roller is pivotable and / or adjustable.

14. Plant for the production of a nonwoven fabric according to one of the preceding claims 6 to 13, characterized in that the circular screen former has a dilution water control.

15. Plant for the production of a nonwoven fabric according to any one of the preceding claims 6 to 14, characterized in that the circular screen former has a stock head heating system.

16. Plant for the production of a nonwoven fabric according to one of the preceding claims 6 to 15, characterized in that the circular screen former has an edge extraction system.

17. Plant for the production of a nonwoven fabric according to any one of the preceding claims 6 to 16, characterized in that the rotary screen former has a frame designed to be at least partially mounted below ground and / or has a clearance for the passage of the circulating belt of the plant.

18. Plant for the production of a nonwoven fabric according to claim 6, characterized by at least one device designed to introduce a further nonwoven fabric into the plant.

19. Plant for the production of a nonwoven fabric according to claim 18, characterized in that the device is designed as a carding and / or unwinding station and / or spunbond nonwoven plant.

20. Method for producing a nonwoven fabric in which a fiber suspension is deposited on a rotating cylinder which is designed to draw off at least some of the liquid from the fiber suspension, so that a layer of wet-laid fibers is formed, which is captured at the top by means of a circulating belt and transferred to another circulating belt, wherein the layer of wet-laid fibers is solidified and dried alone or together with at least one other nonwoven fabric.

21. Method according to claim 20, characterized in that the position of wet-laid fibers between the cylinder and the circulating belt is compacted.

22. Method according to claim 20, characterized in that the layer of wet-laid fibers is laid on a first nonwoven fabric which is transported on the further circulating belt.

23. Method according to claim 22, characterized in that the layer of wet-laid fibers is covered by a further nonwoven fabric before consolidation.

24. Method according to claim 20, characterized in that the layer of wet-laid fibers consists of biodegradable fibers with a basis weight of 10 - 50 g / m² 2 consists.