PROCESS FOR THE PRODUCTION OF SPUNBONDED NONWOVEN

Abstract

The invention relates to a process (100, 101) for the production of spunbonded nonwovens (1.1, 1.2, 1.3) and a device (200, 201) for the production of spunbonded nonwovens (1.1, 1.2, 1.3), wherein, in the process (100, 101), a spinning mass (2) is extruded through a plurality of nozzle holes (4.1, 4.2, 4.3) of at least a first spinneret (3.1) and a second spinneret (3.2) to form filaments (5.1, 5.2, 5.3) and the filaments (5.1, 5.2, 5.3) are drawn, in each case, in the extrusion direction, with the filaments (5.1) of the first spinneret (3.1) being deposited on the conveyor belt (9) to form a first spunbonded nonwoven (1.1) and the filaments (5.2) of the second spinneret (3.2) being deposited on the conveyor belt (9) to form a second spunbonded nonwoven (1.2) over the first spunbonded nonwoven (1.1) in order to obtain a multi-layered spunbonded nonwoven (10). For increasing the throughput of the process, it is suggested that the multi-layered spunbonded nonwoven (10) is separated into at least the first spunbonded nonwoven (1.1) and the second spunbonded nonwoven (1.2) in a subsequent step and the first and second spunbonded nonwovens (1.1, 1.2) after separation each undergo a hydroentanglement (15.1, 15.2) and optionally a drying (12) individually and/or are each wound up individually.

Claims

1. A process for the production of spunbonded nonwovens (1.1, 1.2, 1.3), wherein a spinning mass (2) is extruded through a plurality of nozzle holes (4.1, 4.2, 4.3) of at least a first spinneret (3.1) and a second spinneret (3.2) to form filaments (5.1, 5.2, 5.3) and the filaments (5.1, 5.2, 5.3) are drawn, in each case, in the extrusion direction, with the filaments (5.1) of the first spinneret (3.1) being deposited on the conveyor belt (9) to form a first spunbonded nonwoven (1.1) and the filaments (5.2) of the second spinneret (3.2) being deposited on the conveyor belt (9) to form a second spunbonded nonwoven (1.2) over the first spunbonded nonwoven (1.1) in order to obtain a multi-layered spunbonded nonwoven (10), characterized in that the multi-layered spunbonded nonwoven (10) is separated into at least the first spunbonded nonwoven (1.1) and the second spunbonded nonwoven (1.2) in a subsequent step and after separation the first and second spunbonded nonwovens (1.1, 1.2) each undergo a hydroentanglement (15.1, 15.2) and optionally a drying (12) individually and/or are each wound up individually.

2. A process according to claim 1, characterized in that the multi-layered spunbonded nonwoven (10) is subjected to at least one treatment step (11, 12) before it is unravelled into at least the first and the second spunbonded nonwovens (1.1, 1.2).

3. A process according to claim 2, characterized in that the at least one treatment step (11, 12) of the multi-layered spunbonded nonwoven (10) is selected from the group consisting of: a washing (11), a drying (12).

4. A process according to claim 3, characterized in that the washing (11) is a multi-stage countercurrent washing.

5. A process according to any of claims 2 to 4, characterized in that the at least one treatment step (11, 12) of the multi-layered spunbonded nonwoven (10) is a hydroentanglement, whereby the first and second spunbonded nonwoven (1.1, 1.2) within the multi-layered spunbonded nonwoven (10) still remain separable non-destructively.

6. A process according to any of claims 1 to 5, characterized in that a drawing air stream for drawing the filaments (5.1, 5.2) is assigned to each of the first and the second spinnerets (3.1, 3.2).

7. A process according to any of claims 1 to 6, characterized in that the spunbonded nonwoven (1.1, 1.2, 1.3) is a cellulosic spunbonded nonwoven (1.1, 1.2, 1.3) and the spinning mass (2) is a solution of cellulose in a direct solvent, particularly a tertiary amine oxide.

8. A process according to any of claims 1 to 7, characterized in that the filaments (5.1, 5.2) are coagulated at least partly after they have been extruded from the first and the second spinnerets (3.1, 3.2).

9. A process according to claim 8, characterized in that a coagulation air stream (7.1, 7.2) comprising a coagulation liquid for an at least partial coagulation of the filaments (5.1, 5.2) is assigned to each of the first and the second spinnerets (3.1, 3.2).

10. A process according to claim 9, characterized in that the coagulation liquid is a mixture of water and a direct solvent for cellulose, particularly a tertiary amine oxide.

11. A device for the production of spunbonded nonwoven (1,1, 1.2, 1.3), comprising at least a first spinneret (3.1) and a second spinneret (3.2) for extruding a spinning mass (2) into filaments (5.1, 5.2, 5.3), the spinnerets (3.1, 3.2, 3.3) comprising drawing devices (4.1, 4.2, 4.3) for drawing the extruded filaments (5.1, 5.2, 5.3), and comprising a conveyor belt (9) for depositing the drawn filaments (5.1, 5.2, 5.3) and forming at least a first and a second spunbonded nonwoven (1.1, 1.2), characterized in that the second spinneret (3.2) is arranged downstream of the first spinneret (3.1) in the conveying direction of the conveyor belt (9) in such a way that the second spunbonded nonwoven (1.2) is deposited on the conveyor belt (9) over the first spunbonded nonwoven (1.1) to form a multi-layered spunbonded nonwoven (10) and that the device (200, 201) comprises a separation device (13) fed via the conveyor belt (9) for unravelling the multi-layered spunbonded nonwoven (10) into individual spunbonded nonwovens (1.1, 1.2, 1.3).

12. A device according to claim 11, characterized in that the device (200, 201) comprises a washing (11) to wash the multi-layered spunbonded nonwoven (10), which is arranged between the spinnerets (3.1, 3.2, 3.3) and the separation device (13) in the conveying direction of the conveyor belt (9).

13. A device according to claim 11 or 12, characterized in that the device (200, 201) comprises at least a first and a second winding device (14.1, 14.2), with the winding devices (14.1, 14.2, 14.3) being fed by the seperation device (13).

14. A device according to claim 13, characterized in that the device (200, 201) comprises at least a first and a second hydroentanglement (15.1, 15.2), with a hydroentanglement (15.1, 15.2, 15.3) being provided, in each case, between a separation device (13) and a winding device (14.1, 14.2, 14.3).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The embodiment variants of the invention are described in more detail below with reference to the drawings.

[0042] FIG. 1 shows a schematic illustration of the process as well as of a device according to a first embodiment variant, and

[0043] FIG. 2 shows a schematic illustration of the process as well as of a device according to a second embodiment variant.

WAYS OF IMPLEMENTING THE INVENTION

[0044] FIG. 1 shows a schematic illustration of the process 100 according to a first embodiment of the invention for the simultaneous production of several cellulosic spunbonded nonwovens 1.1, 1.2, 1.3 and a corresponding device 200 for performing the process. In a first process step, a spinning mass 2 is produced from a cellulosic raw material and supplied to a first spinneret 3.1, a second spinneret 3.2 and a third spinneret 3.3 of the device 200. The cellulosic raw material for producing the spinning mass 2, which production is not shown in further detail in the figures, can be a conventional pulp made of wood or other plant-based starting materials. However, it is also conceivable that the cellulosic raw material consists of production waste from the production of spunbonded nonwoven or recycled textiles. In this case, the spinning mass 2 is a solution of cellulose in NMMO and water, with the cellulose content in the spinning mass ranging between 3% by weight and 17% by weight.

[0045] The device 200 comprises three spinnerets 3.1, 3.2, 3.3 for extruding a spinning mass 2 into filaments 5.1, 5.2, 5.3. In doing so, the spinning mass 2 is extruded in the spinnerets 3.1, 3.2, 3.3, in each case, through a plurality of nozzle holes 4.1, 4.2, 4.3, which are allocated to the respective spinneret 3.1, 3.2, 3.3, to form the filaments 5.1, 5.2, 5.3. In addition, each spinneret 3.1, 3.2, 3.3 comprises drawing devices 4.1, 4.2, 4.3 for drawing the extruded filaments 5.1, 5.2, 5.3, whereby a drawing air stream for drawing is allocated to each of the first, the second and the third spinnerets 3.1, 3.2, 3.3. For this purpose, drawing air 6 is supplied to the drawing devices in the spinnerets 3.1, 3.2, 3.3, and the filaments 5.1, 5.2, 5.3 are drawn by the drawing air stream in the extrusion direction as they exit from the spinnerets 3.1, 3.2, 3.3. In doing so, the drawing air 6 can emerge from openings in the spinnerets 3.1, 3.2, 3.3 between the nozzle holes 4.1, 4.2, 4.3 and can be directed as a drawing air stream directly onto the extruded filaments 5.1, 5.2, 5.3.

[0046] Preferably after or already in the course of drawing, the extruded filaments 5.1, 5.2, 5.3 are charged with one coagulation air stream 7.1, 7.2, 7.3 each, wherein, in each case, at least one coagulation air stream 7.1, 7.2, 7.3 is allocated to the spinnerets 3.1, 3.2, 3.3 and is generated by a coagulation device 8.1, 8.2, 8.3. The coagulation air streams 7.1, 7.2, 7.3 usually comprise a coagulation liquid, for example, in the form of vapour, mist, etc. Due to the contact of the filaments 5.1, 5.2, 5.3 with the coagulation air stream 7.1, 7.2, 7.3 and the coagulation liquid contained therein, the filaments 5.1, 5.2, 5.3 are coagulated at least partly, which, in particular, reduces adhesions between the individual extruded filaments 5.1, 5.2, 5.3.

[0047] The drawn and at least partially coagulated filaments 5.1 of the first spinneret 3.1 are then deposited in a random orientation on a conveyor belt 9 of the device 200 to form a first spunbonded nonwoven 1.1. The second spinneret 3.2 is arranged downstream of the first spinneret 3.1 in the conveying direction of the conveyor belt 9 in such a way that the drawn and at least partially coagulated filaments 5.2 of the second spinneret 3.2 are deposited in a random orientation on the conveyor belt 9 over the first spunbonded nonwoven 1.1 to form a second spunbonded nonwoven 1.2. In the same manner, the drawn and at least partially coagulated filaments 5.3 of the third spinneret 3.3 are deposited on the conveyor belt 9 over the second spunbonded nonwoven 3.2, namely in that the third spinneret 3.3 is arranged downstream of the second spinneret 3.2 in the conveying direction of the conveyor belt 9.

[0048] By depositing the second spunbonded nonwoven 1.2 over the first spunbonded nonwoven 1.1 and the third spunbonded nonwoven 1.3 over the second spunbonded nonwoven 1.2, a multi-layered spunbonded nonwoven 10 is formed in which the spunbonded nonwovens 1.1, 1.2, 1.3 are detachably connected to each other. The detachable connection between the spunbonded nonwovens 1.1, 1.2, 1.3 to form the multi-layered spunbonded nonwoven 10 is thereby constructed in such a way that a non-destructive separation of the multi-layered spunbonded nonwoven 10 into the individual spunbonded nonwovens 1.1, 1.2, 1.3 is possible even after further treatment steps.

[0049] Following the formation, the multi-layered spunbonded nonwoven 10 is guided across the conveyor belt 9 through a washing 11 in which the multi-layered spunbonded nonwoven 10 is washed in order to free it from residues of the solvent, namely the NMMO contained in the spinning mass 2. In a preferred embodiment variant, the washing 11 is, in this case, a multi-stage countercurrent washing, which, however, has not been illustrated in the figures. In a next step, the washed multi-layered spunbonded nonwoven 10 is then supplied to a drying 12 in order to remove the remaining moisture. In particular, the washing 11 is arranged in the conveying direction of the conveyor belt 9 between the spinnerets 3.1, 3.2, 3.3 and a subsequent separation device 13.

[0050] In a further embodiment variant, which is not shown in further detail in the figures, the multi-layered spunbonded nonwoven 10 can be subjected to an additional hydroentanglement, wherein the spunbonded nonwovens 1.1, 1.2, 1.3 within the multi-layered spunbonded nonwoven 10 still remain separable in a non-destructive way.

[0051] The washed and dried multi-layered spunbonded nonwoven 10 is separated into the first spunbonded nonwoven 1.1, the second spunbonded nonwoven 1.2 and the third spunbonded nonwoven 1.3 in a separation device 13 fed with the multi-layered spunbonded nonwoven 10 by the conveyor belt 9, wherein the spunbonded nonwovens 1.1, 1.2, 1.3 are each supplied separately to a winding device 14.1, 14.2, 14.3 in order to obtain the finished spunbonded nonwovens 1.1, 1.2, 1.3 simultaneously. In this case, the separation device 13 has an inlet for the multi-layered spunbonded nonwoven 10 and several outlets for the spunbonded nonwovens 1.1, 1.2, 1.3, with the inlet of the separation device 13 being connected to the dryer 12, and the outlets each being connected to the winding devices 14.1, 14.2, 14.3 for feeding them with the spunbonded nonwovens 1.1, 1.2, 1.3.

[0052] FIG. 2 shows a schematic illustration of a process 101 for the simultaneous production of several cellulosic spunbonded nonwovens 1.1, 1.2, 1.3 according to a second embodiment of the invention, and a corresponding device 201 for performing the process 101. In a first process step, a spinning mass 2—as previously described for the process 200 of the first embodiment—is supplied to a first spinneret 3.1, a second spinneret 3.2 and a third spinneret 3.3 of the device 201 and is extruded into filaments 5.1, 5.2, 5.3, drawn and coagulated at least partly.

[0053] The drawn and at least partially coagulated filaments 5.1 of the first spinneret 3.1 are then again deposited in a random orientation on the conveyor belt 9 to form a first spunbonded nonwoven 1.1, the filaments 5.2 of the second spinneret 3.2 are deposited in a random orientation on the conveyor belt 9 over the first spunbonded nonwoven 1.1 to form a second spunbonded nonwoven 1.2, and the filaments 5.3 of the third spinneret 3.3 are deposited in a random orientation on the conveyor belt 9 over the second spunbonded nonwoven 3.2 to form a third spunbonded nonwoven 1.3. In doing so, as described above, a multi-layered spunbonded nonwoven 10 is again formed in which the spunbonded nonwovens 1.1, 1.2, 1.3 are arranged one on top of the other and are detachably connected to each other.

[0054] Across the conveyor belt 9, the multi-layered spunbonded nonwoven 10 is then passed through a washing 11 in which the multi-layered spunbonded nonwoven 10 is washed and freed from solvent residues (in particular NMMO). In contrast to the first embodiment variant of FIG. 1, the multi-layered spunbonded nonwoven 10 is supplied to a separation device 13 after the washing 11 and is separated into the first spunbonded nonwoven 1.1, the second spunbonded nonwoven 1.2 and the third spunbonded nonwoven 1.3.

[0055] In comparison to the device 101 according to FIG. 1, the device 201 comprises several hydroentanglements 15.1, 15.2, 15.3 for the individual spunbonded nonwovens 1.1, 1.2, 1.3. Then, the spunbonded nonwovens 1.1, 1.2, 1.3 each separately pass through a hydroentanglement 15.1, 15.2, 15.3, in which the mechanical properties of the spunbonded nonwovens 1.1, 1.2, 1.3 can be altered or influenced separately from each other. For example, in the course of the hydroentanglements 15.1, 15.2, 15.3, perforation patterns, embossing patterns or the like can be introduced into the spunbonded nonwovens 1.1, 1.2, 1.3, but this has not been illustrated in further detail in the figures. The hydroentanglements 15.1, 15.2, 15.3 are each provided between the separation device 13 and subsequent winding devices 14.1, 14.2, 14.3 for the spunbonded nonwovens 1.1, 1.2, 1.3.

[0056] The spunbonded nonwovens 1.1, 1.2, 1.3 are then brought together again for a joint drying 12 and, after the joint drying 12, they are again separated into the individual spunbonded nonwovens 1.1, 1.2, 1.3 and supplied to the respective winding devices 14.1, 14.2, 14.3. Separate merging and separation devices may be provided for bringing the spunbonded nonwovens 1.1, 1.2, 1.3 together and separating them before and after the drying 12, which is not shown in the figures.

[0057] In an embodiment variant which is an alternative to the process 101 shown in FIG. 2 and is not illustrated in further detail in the figures, the drying 12 may take place separately after the separation of the multi-layered spunbonded nonwoven 10 in the separation device 13 and after the hydroentanglement 15.1, 15.2, 15.3 for each spunbonded nonwoven 1.1, 1.2, 1.3. Thus, the spunbonded nonwovens 1.1, 1.2, 1.3 do not have to be brought together before drying 12 and separated thereafter.

[0058] In a further embodiment of the invention, the spunbonded nonwovens 1.1, 1.2, 1.3 can be produced by the spinnerets 3.1, 3.2, 3.3 each having different weights per unit area, for example, by changing the mass throughput through the spinnerets 3.1, 3.2, 3.3.