Method for manufacturing a spunbond nonwoven fabric

Abstract

The present invention relates to a method (100) for producing a spunbond nonwoven fabric (1). A spun material (2) is extruded through nozzle holes (4) of at least one spinneret (3, 30) to form filaments (5, 50). The filaments (5, 50) are stretched in the extrusion direction to form a spunbond nonwoven fabric (1), which is then placed on a first conveying device (9), and the spunbond nonwoven fabric (1) is subjected to at least one washing step (10). The aim of the present invention is to increase the throughput of the method without compromising quality. This is achieved by at least partially washing the spunbond nonwoven fabric (1) in a perforated second conveying device (13) having a slower conveyor speed than the first conveying device (9), where the spunbond nonwoven fabric (1) is sprayed with a washing fluid during the washing step (10), which is then at least partially expelled through the perforated second conveying device (13).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a spunbond nonwoven fabric, in which a spun material is extruded through a nozzle hole of at least one spinneret to form filaments, the filaments are drawn in the extrusion direction, deposited on a first conveying device to form a spunbond nonwoven fabric, and the spunbond nonwoven fabric is subjected to at least one washing.

Background Art

[0002] The production of spunbond nonwoven fabrics and nonwoven fabrics, respectively, by the spunbond method on the one hand and the meltblown method on the other hand, is known from the prior art. In the spunbond method (for example, UK Patent Application Publication No. 2114052 A or European Patent Application Publication No. 3088585 A1), filaments are extruded through a nozzle, drawn, and drawn by stretching equipment located directly below. In contrast, in the meltblown method (for example, US Patent No. 5,080,569 A, US Patent No. 4,380,570 A or US Patent No. 5,695,377 A), the extruded filaments are carried by high-temperature and high-speed process air and stretched as soon as they exit the nozzle. In both technologies, the filaments are deposited on a deposition surface, for example, a perforated conveyor belt, in a random orientation to form a nonwoven fabric, transported to a post-processing step, and finally wound up as a nonwoven fabric roll.

[0003] Also, the production of cellulosic spunbond nonwoven fabrics according to the spunbond technology (for example, US Patent No. 8,366,988 A) and by the meltblown technology (for example, US Patent No. 6,358,461 A and US Patent No. 6,306,334 A) is known from the prior art. Lyocell spun materials are extruded and drawn according to known spunbond or meltblown methods, but before deposition on the nonwoven fabric, the filaments are further contacted with a coagulant to regenerate the cellulose and produce dimensionally stable filaments. The moist filaments are finally deposited as a nonwoven fabric in a random orientation.

[0004] The advantages of the method can be particularly evident in the case of washing. Regarding the production of thermoplastic spunbond nonwovens, the solvents that can be used include so-called "dry" spinning methods in which the solvent evaporates independently from the spunbond nonwoven downstream of the calendar or dryer, so washing is generally not necessary. In the simplest case, the spunbond nonwoven is wound directly onto a roll after extrusion and deposition in such a method. However, in the case of spinning methods that require washing, such as for cellulosic spunbond nonwovens, the spunbond nonwoven must ensure a certain retention time in washing so that the solvent can be washed out, so the throughput is usually restricted by the duration of washing. In particular, in the production of each of spunbond nonwovens and nonwoven fabrics having a very low weight per unit area, the aforementioned method shows the disadvantage that it is only possible to increase the throughput in a cost-effective manner without impairing the quality of the spunbond nonwoven to a very limited extent, because, in particular, a very long washing system must be used to achieve the same throughput and / or the same quality as that of a higher weight per unit area.

[0005] Since the spun yarns in cellulosic spunbond technology have a pulp content of only 3 to 17%, a larger amount of spun yarns is required to achieve a comparable throughput in the production of thermoplastic spunbond nonwovens. As a result, more spinnerets must be provided for the same productivity compared to thermoplastic spunbond systems, or a larger spun yarn throughput per spinneret must be achieved respectively. Next, the spunbond nonwoven is washed, solidified, dried, and wound up. International Publication No. WO 2018 / 071928 A1 describes a method for washing cellulosic spunbond nonwovens. The relationship between the retention time, the effectiveness of washing, the cost and duration of washing, and the influence on each of them is explained therein. In particular, a high throughput, which is important for the profitability of the method, and a weight of 10 g / m, which is desirable for many applications 2A high conveying speed is achieved with a low weight per unit area. In this way, from the viewpoints of both requirements, the effectiveness of cleaning and the required duration of cleaning, thus, the costs for mechanical engineering and system engineering, as well as the costs of the system and very long buildings increase.

[0006] From US Patent Application Publication No. 2005 / 0056956 A1, a method for the production of a cellulosic spunbond nonwoven fabric is known, where filaments are deposited on a conveyor drum, water-flow bonded, pressed, and then deposited in the form of a loop in a coagulation bath at a lower conveying speed. Subsequently, the loop is dissolved and the spunbond nonwoven fabric is dried and wound up. However, when used in a commercial production plant, such a method has several disadvantages. For example, at high production speeds, the rotational speeds of the deposition drum and the press roller are, thus, very high, which causes adhesion to the drum surface in the moisture-containing state of the cellulosic spunbond nonwoven fabric. For this reason, the spunbond nonwoven fabric may tear or have defects, or respectively, the spunbond nonwoven fabric may also wind around the deposition drum and the press roller, which is very disadvantageous for economic and safety reasons. Furthermore, the water-flow bonding of the spunbond nonwoven fabric immediately after the filaments are deposited causes partial suction to the newly extruded filaments under vacuum and to the drum. Thereby, the separation of the spunbond nonwoven fabric from the drum is further hindered, and the spunbond nonwoven fabric further tears or has defects. Moreover, the structural changes introduced into the spunbond nonwoven fabric during water-flow bonding are completely or partially removed by the subsequent coagulation bath and the accompanying swelling of the spunbond nonwoven fabric. The specific adjustment of the mechanical and structural properties of the produced spunbond nonwoven fabric is thus significantly hindered. Furthermore, the spunbond nonwoven fabric arranged in the loop is subject to a large resistance force due to the buoyancy of the spunbond nonwoven fabric in the coagulation bath, so it can only be transported through the coagulation bath at a low conveying speed. Therefore, an improvement in throughput is not possible without a dramatic loss in quality.

Summary of the Invention

Problems to be Solved by the Invention

[0007] Accordingly, an object of the present invention is to improve the method for manufacturing the first-mentioned type of spunbond nonwoven fabric in a cost-effective and simple manner without impairing the quality of the spunbond nonwoven fabric, in such a way that the throughput of the method can be increased.

Means for Solving the Problems

[0008] The object is achieved in that the spunbond nonwoven fabric is at least partially subjected to cleaning in a second perforated conveying device having a conveying speed lower than that of the first conveying device, wherein the spunbond nonwoven fabric is sprayed with a cleaning liquid during cleaning, and the cleaning liquid is at least partially discharged through the perforated second conveying device.

[0009] When the spunbond nonwoven fabric is at least partially subjected to cleaning in a second conveying device having a conveying speed lower than that of the first conveying device, i.e., when the conveying speed of the spunbond nonwoven fabric is reduced during at least part of the cleaning compared to the conveying speed of the spunbond nonwoven fabric before cleaning, the holding time of the spunbond nonwoven fabric during cleaning can be increased in a simple manner without providing a more cost-intensive longer cleaning. In this way, a spunbond nonwoven fabric having a predetermined weight per unit area can be obtained at a consistent throughput of the spinneret and a suitable conveying speed during the deposition of the spunbond nonwoven fabric, thereby improving the quality of the resulting spunbond nonwoven fabric, in particular the residual solvent content after cleaning.

[0010] Alternatively, by increasing the throughput of the spinneret of the spinneret and appropriately adjusting the conveying speed when the spunbond nonwoven fabric is being deposited, a spunbond nonwoven fabric having the same weight per unit area and consistent quality can be obtained at a higher throughput.

[0011] Using the method according to the invention, as explained above, the conveying speed due to the spun throughput and the desired weight per unit area can thus be completely decoupled from the conveying speed of the cleaning. As a result, the duration of the cleaning, the length of the system, or the cost of installing and operating the building and thus also the system for carrying out the method can be significantly reduced respectively.

[0012] When the spunbond nonwoven fabric is further sprayed with the cleaning liquid during cleaning and the cleaning liquid is at least partially discharged through the second perforated conveying device, the reliability and efficiency of the cleaning can be further enhanced.

[0013] The assisted transport of the spunbond nonwoven fabric by the second conveying device during cleaning ensures that reliable and efficient cleaning can be achieved even at high conveying speeds, since neither buoyancy nor water resistance acts on the spunbond nonwoven fabric compared to bath cleaning. In fact, such buoyancy or water resistance in the cleaning bath can respectively cause entanglement or agglomeration of the spunbond nonwoven fabric, so that the spunbond nonwoven fabric can become unusable at high conveying speeds in the range of approximately 100 m / min to 500 m / min. This is especially the case when the spunbond nonwoven fabric has a lower conveying speed in the cleaning than before cleaning, since the lower conveying speed results in an excessive length of the spunbond nonwoven fabric during cleaning. By spraying with the cleaning liquid, the overly long spunbond nonwoven fabric can be reliably maintained by the second conveying device.

[0014] By directly discharging the cleaning liquid through the perforated second conveying device, on the one hand, hypertrophy of the spunbond nonwoven fabric and, on the other hand, excessive swelling can be avoided. The spunbond nonwoven fabric completely immersed in the cleaning liquid can actually absorb 10 to 15 times the amount of liquid relative to its own weight. However, since the non-dried spunbond nonwoven fabric has very low strength, such complete immersion of the spunbond nonwoven fabric further weakens the structure, thus increasing the number of tears and thereby preventing reliable further transport. Therefore, the throughput of the method can be increased by the cleaning according to the invention without a negative impact on the quality of the spunbond nonwoven fabric produced.

[0015] After washing, the spunbond nonwoven fabric can preferably have a liquid content of less than 5 kg / kg based on its dry weight. In a further embodiment, the liquid content can be less than 4 kg / kg, or in yet another preferred embodiment, less than 3 kg / kg. The low liquid content can preserve the internal structure and stability of the spunbond nonwoven fabric, thereby enabling transportation even at high conveyance speeds.

[0016] For the purposes of the present invention, within the meaning of this disclosure, a spunbond nonwoven fabric is understood to be a nonwoven fabric formed directly by depositing extruded filaments, where the filaments are essentially continuous filaments and are deposited in a random orientation to form the spunbond nonwoven fabric, it being noted.

[0017] The conveying device within the meaning of the present invention may be understood as any device suitable for conveying or transporting a spunbond nonwoven fabric at a specific conveyance speed. Such a conveying device may be, for example, a conveyor belt, a conveyor drum, a conveyor roller, etc. In a preferred embodiment of the present invention, the conveying device is designed as a conveyor belt.

[0018] The aforementioned advantages can be achieved especially when the conveyance speed of the second conveying device is reduced by a factor of 1 to 1000 with respect to the first conveying device. For example, at a factor of 2, the throughput can be doubled while keeping the weight per unit area consistent and the cleaning duration consistent, or the effectiveness of the cleaning can be considerably enhanced. For example, doubling the holding time during cleaning has been shown to increase the efficiency beyond a linear pattern, resulting in a reduction of the solvent residue in the finished spunbond nonwoven fabric by a factor of, for example, 4 to 8. Before cleaning, the conveyance speed is preferably reduced between 1 and 100 times, or particularly preferably between 1 and 25 times.

[0019] Furthermore, when the spunbond nonwoven fabric accumulates in the loop of the second conveying device, the reproducibility of the method can be further improved. In this way, that is, it is particularly easy to follow the procedure to address the reduction in the conveying speed within the washing. By doing so, in the loop, there can be formed essentially parallel overlapping sections of the spunbond nonwoven fabric, thereby enabling efficient washing of the spunbond nonwoven fabric and allowing it to be pulled apart without any damage after washing. In particular, the loop can be pulled apart by a faster conveying device after washing.

[0020] Directly after the spunbond nonwoven fabric accumulates and is formed on the first conveying device, the spunbond nonwoven fabric can preferably accumulate on the second conveying device. In this context, "directly after deposition" is understood to mean that no further processing steps of the spunbond nonwoven fabric on the first conveying device are contemplated between the deposition and formation of the spunbond nonwoven fabric on the first conveying device and the deposition on the second conveying device.

[0021] By doing so, the spunbond nonwoven fabric can preferably accumulate on the second conveying device before washing, particularly preferably directly before washing. Thus, before washing, or directly before washing respectively, the conveying speed of the spunbond nonwoven fabric is reduced. In this context, "directly before washing" is understood to mean that no further processing steps of the spunbond nonwoven fabric on the second conveying device are contemplated before washing. Therefore, the spunbond nonwoven fabric can preferably undergo complete washing on the second conveying device.

[0022] Therefore, between the deposition and formation of the spunbond nonwoven fabric on the first conveying device and the washing on the second conveying device, preferably no further processing steps of the spunbond nonwoven fabric need to be contemplated.

[0023] Furthermore, after washing, the spunbond nonwoven fabric may undergo further processing steps in the third conveying device at a conveying speed higher than that of the second conveying device. For this purpose, the spunbond nonwoven fabric can be deposited on the third conveying device, whereby the excess length of the spunbond nonwoven fabric or the loops formed therein, respectively, do not become entangled, and the spunbond nonwoven fabric can be further processed again at a higher conveying speed. By doing so, the third conveying device can preferably have essentially the same conveying speed as the first conveying device.

[0024] When the conveying speed of the third conveying device is increased again between 1 and 1000 times that of the second conveying device, a particularly versatile method can be provided, whereby direct further processing of the spunbond nonwoven fabric after washing at a higher conveying speed becomes possible. Therefore, after washing, the spunbond nonwoven fabric can preferably be accelerated back to the same conveying speed as before washing and undergo further processing steps. The conveying speed of the third conveying device preferably increases between 1 and 100 times, particularly preferably between 1 and 25 times, that of the second conveying device.

[0025] The advantages mentioned above can be achieved in this way, particularly when the spunbond nonwoven fabric is subjected to water entanglement and / or drying after washing. In practice, water entanglement can preferably be carried out at the original conveying speed of the spunbond nonwoven fabric, since, unlike washing, there is no need to extend the holding time.

[0026] Furthermore, using water entanglement after washing enables particularly reliable control of the structural and internal properties of the spunbond nonwoven fabric. For example, during the water entanglement process, the patterns or perforations remaining in the finished spunbond nonwoven fabric can each be permanently imprinted.

[0027] After the water stream complexing, the spunbond nonwoven fabric can be dried again to obtain a finished spunbond nonwoven fabric. The processed and finished spunbond nonwoven fabric can then optionally be wound onto a roll by a winding device.

[0028] The washing efficiency can be further improved when the washing is a multi-stage countercurrent washing. That is, in countercurrent washing, the washing liquid used for washing, especially water, circulates through several washing stages, where fresh washing liquid is supplied at the end of the washing and discharged through the perforated second conveying device, flowing continuously in the same manner as the upstream washing stage, and the used washing liquid is discharged at the beginning of the washing.

[0029] When the spun material is further extruded into filaments through at least a first spinneret and a second spinneret, the throughput of the method can be further increased, where the filaments of the first spinneret are deposited on the first conveying device to form a first spunbond nonwoven fabric, the filaments of the second spinneret are deposited on the first conveying device to form a second spunbond nonwoven fabric, and here, the filaments of the second spinneret are deposited on the first conveying device to form a second spunbond nonwoven fabric covering the first spunbond nonwoven fabric in order to obtain a multi-layered spunbond nonwoven fabric.

[0030] In fact, when the filaments of the second spinneret are deposited on the first conveying device to form a second spunbond nonwoven fabric covering the first spunbond nonwoven fabric in order to obtain a multi-layered spunbond nonwoven fabric, at least two spinnerets are provided for the simultaneous formation of at least two spunbond nonwoven fabrics, so that the throughput of the method can be increased in a simple manner. However, the multi-layered spunbond nonwoven fabric formed thereby can be further processed by existing means instead of using a single spunbond nonwoven fabric. The second spinneret is preferably located downstream of the first spinneret in the conveying direction of the first conveying device.

[0031] The multilayered spunbond nonwoven fabric thus formed consists of a first and a second spunbond nonwoven fabric, with the second spunbond nonwoven fabric disposed on top of the first. The first and second spunbond nonwoven fabrics can in this case be interconnected (e.g., by adhesion) such that the multilayered spunbond nonwoven fabric forms a unit that can undergo further process steps, but can be essentially loosened to the first and second spunbond nonwoven fabrics without causing any structural damage to them.

[0032] If the multilayered spunbond nonwoven fabric is loosened to at least the first and second spunbond nonwoven fabrics in subsequent steps, at least two independent spunbond nonwoven fabrics can be obtained again in the process of the method. A cost-effective method for the production of spunbond nonwoven fabrics with improved throughput can be thus created.

[0033] Similarly, the spun material can be extruded into filaments through a third and further spinnerets, and the filaments can in each case be stretched in the extrusion direction, where the filaments of the third spinneret are deposited on a first conveyor device to form a third spunbond nonwoven fabric covering the second spunbond nonwoven fabric to obtain a multilayered spunbond nonwoven fabric, or respectively, the filaments of each further spinneret are deposited on a first conveyor device to form a further spunbond nonwoven fabric covering the previously existing spunbond nonwoven fabric in each case to obtain a multilayered spunbond nonwoven fabric.

[0034] Such a multilayered spunbond nonwoven fabric may include a plurality of spunbond nonwoven fabrics that can be separated from each other in subsequent process steps.

[0035] In particular, when the multilayer spunbond nonwoven fabric is subjected to at least one treatment step before being separated into at least a first and a second spunbond nonwoven fabric, the aforementioned advantages of the method can be demonstrated. In this way, the combined treatment of the first and second spunbond nonwoven fabrics is actually carried out in the form of a multilayer spunbond nonwoven fabric, and thus the throughput of the method can be significantly increased compared to the separate treatment of the spunbond nonwoven fabrics.

[0036] This can be clearly demonstrated especially when at least one treatment step of the multilayer spunbond nonwoven fabric is the cleaning according to the invention in a second conveying device having a conveying speed reduced with respect to the conveying speed of the first conveying device. By the method according to the invention including the combined cleaning of the first and second spunbond nonwoven fabrics in the multilayer spunbond nonwoven fabric, the duration of the cleaning is actually significantly reduced, and furthermore, the throughput can be increased respectively.

[0037] If the spunbond nonwoven fabric is a multilayer spunbond nonwoven fabric, where the filaments extruded from each spinneret form respective layers of the spunbond nonwoven fabric, and at least two continuously arranged spinnerets are provided such that one is deposited on top of the other so that the multilayer spunbond nonwoven fabric is produced, the method according to the invention can be characterized by high flexibility. The multilayer spunbond nonwoven fabric can then be reliably cleaned at a reduced conveying speed using the method according to the invention as before.

[0038] When the filaments are stretched by a stretching air flow after being extruded from the spinneret, the reliability of the method can be further increased. This enables the control of, among other things, the conditions of filament extrusion and stretching, and thus the adaptation of the internal properties of the spunbond nonwoven fabric. By doing so, the stretching air flow is directed towards the extruded filaments from each spinneret.

[0039] In particular, the drawing air stream can have a pressure in the range of 0.05 bar to 5 bar, preferably 0.1 bar to 3 bar, particularly preferably 0.2 bar to 1 bar. In particular, the drawing air stream can further have a temperature in the range of 20 °C to 200 °C, preferably 60 °C to 160 °C, particularly preferably 80 °C to 140 °C.

[0040] The method according to the invention can be distinguished in particular from the perspective of the production of cellulosic spunbond nonwovens, and the spun material is a lyocell spun material, i.e., a solution of cellulose in a direct solvent for cellulose.

[0041] Such a direct solvent for cellulose is a solvent in which cellulose is present in a dissolved state without being derivatized. Preferably, this can be a tertiary amine oxide, a mixture of NMMO (N-methylmorpholine-N-oxide) and water. As an alternative, however, an ionic liquid, or a mixture with water, for example, is also suitable as a direct solvent.

[0042] In this case, the cellulose content in the spun material may be in the range of 3 wt% to 17 wt%, in a variation of the preferred embodiment 5 wt% to 15 wt%, and in a variation of the particularly preferred embodiment 6 wt% to 14 wt%.

[0043] In the production of cellulosic spunbond nonwovens, a number of improvements and advantages regarding the profitability of the production plant, the operation of the plant, and the product quality result from the method according to the invention. Since several loops with one shifted parallel to the other can be washed simultaneously, the conveying speed of the spunbond nonwoven can be significantly reduced during washing. The lower conveying speed reduces both the cost and the complexity of the production plant.

[0044] Surprisingly, it has been shown that spunbond nonwovens deposited at a reduced conveyance speed with one loop positioned parallel on top of the other can be washed with greater efficiency than spunbond nonwovens at a conveyance speed that is not more significantly reduced. Even after multi-stage countercurrent washing, the loops can be dissolved without being destroyed, and the spunbond nonwovens can be accelerated back to the original conveyance speed.

[0045] 10 g / m 2 Even at a low weight per unit area of 10 g / m or less, the spunbond nonwovens have been shown to be sufficiently stable to be deposited on the loops, washed at a reduced speed, and then accelerated again to the original conveyance speed in order to be solidified thereon at the original conveyance speed in a further process, dried, and wound up.

[0046] The throughput of cellulose per spinneret may preferably be in the range between 5 kg / hour per meter of spinneret length and 500 kg / hour per meter of spinneret length.

[0047] The advantages according to the present invention can be clearly demonstrated especially when the weight per unit area of the spunbond nonwoven is between 5 g / m 2 (gsm) and 500 g / m 2 , preferably between 10 g / m 2 and 250 g / m 2 , particularly preferably between 15 g / m 2 and 100 g / m 2 .

[0048] The conveyance speed of the spunbond nonwoven when deposited, or the conveyance speed of the first conveyance device, may each preferably be in the range between 1 m / min and 2000 m / min, preferably between 10 m / min and 1000 m / min, particularly preferably between 15 m / min and 500 m / min.

[0049] Furthermore, when the filaments extruded and drawn from the spinneret are partially solidified, the internal structure of the spunbond nonwoven can be reliably controlled.

[0050] For this purpose, a coagulation air stream containing a coagulation liquid for at least partial coagulation of the filaments can be assigned to the spinneret, thereby enabling special control of the internal structure of the spunbond nonwoven fabric. In this case, the flow of the coagulation air may preferably be a fluid containing water and / or a coagulant, such as a fluid containing a gas, mist, vapor, etc.

[0051] If the coagulation liquid is a mixture of water and a direct solvent for cellulose, particularly reliable coagulation of the extruded filaments can thereby be achieved. In particular, the coagulation liquid may be a mixture of deionized water and 0 wt% to 40 wt% of NMMO, preferably 10 wt% to 30 wt% of NMMO, and particularly preferably 15 wt% to 25 wt% of NMMO.

[0052] In this case, the amount of the coagulation liquid may preferably be in the range of 50 l / hour to 10,000 l / hour, more preferably 100 l / hour to 5,000 l / hour, and particularly preferably 500 l / hour to 2,500 l / hour per meter of the coagulation nozzle.

[0053] When using the spinneret of the method according to the present invention or the apparatus according to the present invention respectively, a single-row slot nozzle, a multi-row needle nozzle or preferably a column nozzle having a length of 0.1 m to 6 m known from the prior art (US Patent No. 3,825,380 A, US Patent No. 4,380,570 A, International Publication No. 2019 / 068764 A1) can preferably be used.

[0054] Modifications of embodiments of the present invention will be described in more detail below with reference to the drawings.

Brief Description of the Drawings

[0055]

Figure 1

Embodiments for Carrying Out the Invention

[0056] Figure 1 shows a schematic illustration of a method 100 according to a variation of a first embodiment for manufacturing a cellulosic spunbond nonwoven fabric 1, and a corresponding apparatus 200 in which the method 100 is carried out. In the steps of the first method, the spun yarn 2 is manufactured from a cellulosic raw material and supplied to the spinneret 3 of the apparatus 200. The cellulosic raw material for manufacturing the spun yarn 2, which is not shown in more detail in the figure, may be a conventional pulp manufactured from wood or other plant-based starting materials. However, it is also conceivable that the cellulosic raw material consists of manufacturing waste from the production of spunbond nonwovens or recycled textiles. In this case, the spun yarn 2 is a solution of cellulose in NMMO and water, and the cellulose content in the spun yarn 2 is in the range between 3 wt% and 17 wt%.

[0057] Next, the spun yarn 2 is extruded through a plurality of nozzle holes 4 into the spinneret 3 to form filaments 5. By supplying stretching air 6 to the stretching facility in the spinneret 3, when it exits the spinneret 3, the filaments 5 are stretched by the stretching air flow. By doing so, the stretching air 6 can come out from the openings of the spinneret 3 between the nozzle holes 4 and can be directed as a stretching air flow directly onto the extruded filaments 5 (not shown in more detail in the figure). After or already during the stretching, the extruded filaments 5 are subjected to a coagulation air flow 7 generated by the coagulation device 8. The coagulation air flow 7 usually contains a coagulation liquid in the form of, for example, steam, mist, etc. By the contact of the filaments 5 with the coagulation air flow 7 and the coagulation liquid contained therein, the filaments 5 are at least partially coagulated, particularly reducing the adhesion between the individual extruded filaments 5. The at least partially stretched and precipitated filaments 5 are then randomly deposited on a first conveyor belt 9 as a first conveying device 9 to form the spunbond nonwoven fabric 1. By the conveyor belt 9, the spunbond nonwoven fabric 1 is then passed through further processing steps 10, 11, 12. By doing so, the spunbond nonwoven fabric 1 is subsequently subjected to at least one washing 10.

[0058] To extend the retention time of the spunbond nonwoven fabric 1 in the washing 10, the spunbond nonwoven fabric 1 is deposited directly onto the second conveyor belt 13 as a second conveying device 13 having a reduced conveying speed with respect to the first conveying device 9, before the washing 10. The conveying speed of the spunbond nonwoven fabric 1 within the washing 10 is thus reduced as compared to the conveying speed of the spunbond nonwoven fabric 1 before the washing 10, i.e., while the filaments 5 are deposited on the first conveyor belt 9. By doing so, the conveying speed is preferably reduced by a factor of 1 to 1000. In a variation of another embodiment, the factor is between 1 and 100, and in a variation of yet another embodiment, between 1 and 25. To adjust the difference in conveying speed between the first conveyor belt 9 and the second conveyor belt 13 in the spunbond nonwoven fabric 1, the spunbond nonwoven fabric 1 is deposited in a loop 14 on the second conveyor belt 13. The spunbond nonwoven fabric 1 disposed in the loop 14 is then subjected to the washing 10, where the solvent residues are essentially removed from the spun material 2.

[0059] After the washing 10, the spunbond nonwoven fabric 1 is deposited onto a third conveyor belt 15 having a higher conveying speed with respect to the second conveyor belt 13. By doing so, the third conveyor belt 15 preferably has the same conveying speed as the first conveyor belt 9, and as a result, the loop 14 is pulled out completely again. In a variation of a further embodiment not shown in more detail, the third conveyor belt 15 can also have another conveying speed increased by a factor between 1 and 1000, preferably between 1 and 100, particularly preferably between 1 and 25, different from the first conveyor belt 9 with respect to the second conveyor belt 13. On the third conveyor belt 15, the spunbond nonwoven fabric 1 is subjected to the hydroentangling 11, and the internal structure of the spunbond nonwoven fabric 1 can be further adjusted. Additionally, in the process of the hydroentangling 11, a further perforation pattern, embossing pattern, etc. can be introduced into the spunbond nonwoven fabric 1, however, this is not shown in more detail in the figures.

[0060] Finally, to obtain the finished spunbond nonwoven fabric 1, the spunbond nonwoven fabric 1 is subjected to drying 12, and the method 100 is concluded with an optional winding 16 and / or packing process.

[0061] In a variation of a further embodiment shown only in the figures, the apparatus 100 or method 200 may each have at least a first spinneret 3 and a second spinneret 30, and the spun material 2 is extruded simultaneously through the first spinneret 3 and the second spinneret 30 to form filaments 5, 50. By doing so, the filaments 5, 50 are each stretched in the extrusion direction and at least partially solidified, and the filaments 5 of the first spinneret 3 are deposited on the conveyor belt 9 to form the first spunbond nonwoven fabric 1, and the filaments 50 of the second spinneret 30 are deposited on the conveyor belt 9 to form a second spunbond nonwoven fabric. The filaments 50 of the second spinneret 30 are deposited on the conveyor belt 9 to form a second spunbond nonwoven fabric that covers the first spunbond nonwoven fabric 1 to obtain a multilayered spunbond nonwoven fabric (not shown in more detail in the figure).

[0062] Preferably, the first spunbond nonwoven fabric 1 and the second spunbond nonwoven fabric are jointly subjected to washing 10 in the form of a multilayered spunbond nonwoven fabric, where the multilayered spunbond nonwoven fabric is deposited on the second conveyor belt 13 in the loop 14 at a conveying speed lower than the conveying speed of the first conveyor belt 9. Preferably, then, the multilayered spunbond nonwoven fabric can be loosened at least for the first spunbond nonwoven fabric 1 and the second spunbond nonwoven fabric in a process following the washing 10, and the first spunbond nonwoven fabric 1 and the second spunbond nonwoven fabric are separately subjected to further processes such as water entanglement 11 and / or drying 12 after being loosened.

[0063] Alternatively, the first spunbond nonwoven fabric 1 and the second spunbond nonwoven fabric may also jointly undergo water entanglement 11, thereby permanently interconnecting to form a multilayered spunbond nonwoven fabric.

[0064] Similarly, the first spunbond nonwoven fabric 1 and the second spunbond nonwoven fabric each have different internal properties, for example, different weights per unit area, and thus can form a multilayered spunbond nonwoven fabric having a variable cross-section property.

[0065] In a further embodiment variation not described in the figures, the first conveying device 9 is a conveyor drum and the second conveying device 13 is a conveyor belt.

[0066] In yet another embodiment, both the first conveying device 9 and the second conveying device 13 are conveyor drums.

Claims

1. A method for manufacturing a spunbond nonwoven fabric (1), comprising: Extruding a spun material (2) through nozzle holes (4) of at least one spinneret (3, 30) to form filaments (5, 50); Stretching the filaments (5, 50) in the extrusion direction and depositing them on a first conveying device (9) to form a spunbond nonwoven fabric (1); Subjecting the spunbond nonwoven fabric (1) to at least one washing (10), wherein The spunbond nonwoven fabric (1) is at least partially subjected to washing (10) by a perforated second conveying device (13) having a conveying speed lower than that of the first conveying device (9). The spunbond nonwoven fabric (1) is sprayed with a washing liquid during washing (10), and the washing liquid is at least partially discharged through the perforated second conveying device (13); The spunbond nonwoven fabric (1) is deposited on the second conveying device (13) at a reduced conveying speed in loops (14) where one is positioned parallel to the other, characterized in that it is a method.

2. The method according to claim 1, characterized in that the conveying speed of the second conveying device (13) is reduced to be greater than 1 times and less than 1000 times that of the first conveying device (9).

3. The method according to claim 2, characterized in that the conveying speed of the second conveying device (13) is reduced to be greater than 1 times and less than 100 times that of the first conveying device (9).

4. The method according to claim 3, characterized in that the conveying speed of the second conveying device (13) is reduced to be greater than 1 times and less than 25 times that of the first conveying device (9).

5. After washing (10), the spunbond nonwoven fabric (1) is subjected to further processing steps (11, 12) by a third conveying device (15) having a conveying speed higher than that of the second conveying device (13), characterized in that it is a method according to any one of claims 1 to 4.

6. The method according to claim 5, characterized in that the conveying speed of the third conveying device (15) is increased to be greater than 1 times and less than 1000 times that of the second conveying device (13).

7. The method according to claim 6, characterized in that the conveying speed of the third conveying device (15) is increased to be greater than 1 times and less than 100 times that of the second conveying device (13). The method according to claim 7, characterized in that the conveying speed of the third conveying device (15) is increased by more than 1 times and less than 25 times with respect to the second conveying device (13).

9. The method according to claim 5, characterized in that the third conveying device (15) has substantially the same conveying speed as the first conveying device (9).

10. The method according to any one of claims 1 to 9, characterized in that the spunbond nonwoven fabric (1) is subjected to water stream bonding (11) and / or drying (12) after washing (10).

11. The method according to any one of claims 1 to 10, characterized in that the washing (10) is a multi-stage countercurrent washing.

12. The method according to any one of claims 1 to 11, characterized in that the spunbond nonwoven fabric (1) is deposited directly on the second conveying device (13) after being deposited and formed on the first conveying device (9).

13. The method according to any one of claims 1 to 12, characterized in that the spunbond nonwoven fabric (1) is deposited directly on the second conveying device (13) before washing (10).

14. The spun material (2) is extruded into filaments (5, 50) through at least the first spinneret (3) and the second spinneret (30), wherein the filaments (5) of the first spinneret (3) are deposited on the first conveying device (9) to form the first spunbond nonwoven fabric (1), and the filaments (50) of the second spinneret (30) are deposited on the first conveying device (9) to form the second spunbond nonwoven fabric, wherein the filaments (50) of the second spinneret (30) are deposited on the first conveying device (9) to form a second spunbond nonwoven fabric covering the first spunbond nonwoven fabric (1) in order to obtain a multi-layered spunbond nonwoven fabric. The method according to any one of claims 1 to 13, characterized in that.

15. The method according to claim 14, characterized in that the multi-layered spunbond nonwoven fabric is loosened in a subsequent process at least with respect to the first spunbond nonwoven fabric (1) and the second spunbond nonwoven fabric.

16. The method according to any one of claims 1 to 15, characterized in that the spunbond nonwoven fabric (1) is a cellulosic spunbond nonwoven fabric (1), and the spun material (2) is a solution of cellulose directly in a solvent. **Claim 17**: The method according to claim 16, characterized in that the direct solvent is a tertiary amine oxide. **Claim 18** The method according to any one of claims 1 to 17, characterized in that the filaments (5, 50) are at least partially solidified after extrusion from the spinneret (3, 30), whereby a coagulation air stream (7) containing a coagulation liquid is assigned to the spinneret (3, 30) for at least partial solidification of the filaments (5, 50). **Claim 19** The method according to any one of claims 1 to 18, characterized in that the coagulation liquid is a mixture of water and a direct solvent for cellulose. **Claim 20**: The method according to claim 19, characterized in that the direct solvent is a tertiary amine oxide.

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