Apparatus for the continuous manufacture of a spunbond web

Abstract

An apparatus for the continuous manufacture of a spunbond web from aerodynamically stretched thermoplastic filaments has at least one spinneret, a cooling chamber for cooling the filaments, a stretcher, and a deposition device for the deposition of the filaments to form the spunbond web. At least one filament guide having a plurality of filament-guide gaps opens toward the stretcher between the stretcher and the deposition device, and the filament guide or at least one guide part of the filament guide can be moved such that the filament-guide gap or the stretcher-side openings thereof are displaced transversely to the travel direction of the spunbond web. Thus the filaments or filament bundles guided along or through the filament-guide gap are given a transverse orientation to the travel direction of the spunbond web when deposited onto the deposition device.

Claims

1. An apparatus for the continuous manufacture of a spunbond web from aerodynamically stretched filaments of thermoplastic plastic, the apparatus comprising: at least one spinneret emitting the filaments, a cooling chamber for cooling the filaments emitted by the spinneret, a stretcher for stretching the cooled filaments and forming with the cooling chamber a closed system, a deposition device for depositing the stretched filaments to form the spunbond web and transporting the spunbond web in a travel direction, at least one filament guide having a plurality of filament-guide gaps having stretcher side openings open toward the stretcher and provided between the stretcher and the deposition device such that the filaments emerging from the stretcher are divided into filament bundles by the filament guide or by the at least one guide part of the filament guide and pass through the filament guide-gaps or through the stretcher-side openings of the filament-guide gaps, and means for moving the filament guide or at least one guide part thereof such that the filament-guide gaps or the stretcher-side openings thereof are displaced transversely to the travel direction of the spunbond web and the filament bundles guided along or through the filament-guide gaps are given a transverse orientation to the travel direction of the spunbond web when deposited by the deposition device.

2. The apparatus according to claim 1, wherein the means moves the filament guide or the at least one guide part of the filament guide in a periodic manner.

3. The apparatus according to claim 1, wherein the filament guide has at least one rotatable or rotating shaft, at least one disk adjoins the shaft, the disk forms a side wall of at least one of the filament-guide gaps.

4. The apparatus according to claim 1, wherein the filament guide has at least one rotatable or rotating shaft extending transversely to the travel direction of the spunbond web, a plurality of disks is connected to the shaft, the filament-guide gaps are formed between the disks, and vertical lines extending from different points of an outer circumference or outer region of a one of the disks to a rotation axis of the shaft have different intersection points with a rotation axis of the shaft.

5. The apparatus according to claim 4, wherein at least one portion of all of the disks of the shaft or a majority of the disk surface of these disks is/are at a slant or tilted to the rotation axis of the shaft.

6. The apparatus according to claim 3, wherein at least one deflection of the filament bundles transversely to the travel direction of the spunbond web takes place with each revolution of the shaft.

7. The apparatus according to claim 3, wherein a rotation speed of the shaft can be adjusted and a frequency of deflections of the filament bundles can be adjusted by adjusting the rotation speed of the shaft.

8. An apparatus for the continuous manufacture of a spunbond web from aerodynamically stretched filaments of thermoplastic plastic, the apparatus comprising: at least one spinneret emitting the filaments, a cooling chamber for cooling the filaments emitted by the spinneret, a stretcher for stretching the cooled filaments, a deposition device for depositing the stretched filaments to form the spunbond web and transporting the spunbond web in a travel direction, at least one filament guide having a plurality of filament-guide gaps having stretcher side openings open toward the stretcher and provided between the stretcher and the deposition device, the filament guide having at least two rotatable or rotating shafts extending transversely to the travel direction of the spunbond web and a plurality of disks connected to each shaft, and means for moving the filament guide or the at least two rotatable or rotating shafts thereof such that the filament-guide gaps or the stretcher-side openings thereof are displaced transversely to the travel direction of the spunbond web and filament bundles guided along or through the filament-guide gaps are given a transverse orientation to the travel direction of the spunbond web when deposited by the deposition device.

9. The apparatus according to claim 8, wherein the two shafts are at the same vertical level or substantially at the same vertical level and the disks of one shaft engage into spaces between the disks on the other shaft, and vice versa.

10. The apparatus according to claim 8, wherein the at least two shafts are at different vertical levels and rotation axes of the shafts are offset from one another vertically on opposite sides of a filament curtain emerging from the stretcher.

11. An apparatus for the continuous manufacture of a spunbond web from aerodynamically stretched filaments of thermoplastic plastic, the apparatus comprising: at least one spinneret emitting the filaments, a cooling chamber for cooling the filaments emitted by the spinneret, a stretcher for stretching the cooled filaments, a deposition device for depositing the stretched filaments to form the spunbond web and transporting the spunbond web in a travel direction, at least one filament guide having a plurality of filament-guide gaps having stretcher side openings open toward the stretcher and provided between the stretcher and the deposition device, the guide having at least one shaft rotatable about a rotation axis and extending in the travel direction of the spunbond web, and at least one disk extending longitudinally of the shaft is connected to each shaft, the at least one shaft being reciprocal along and rotatable about the rotation axis, and means for moving the filament guide or the at least one shaft thereof such that the filament-guide gaps or the stretcher-side openings thereof are displaced transversely to the travel direction of the spunbond web and filament bundles guided along or through the filament-guide gaps are given a transverse orientation to the travel direction of the spunbond web when deposited by the deposition device.

12. An apparatus for the continuous manufacture of a spunbond web from aerodynamically stretched filaments of thermoplastic plastic, the apparatus comprising: at least one spinneret emitting the filaments, a cooling chamber for cooling the filaments emitted by the spinneret, a stretcher for stretching the cooled filaments, a deposition device for depositing the stretched filaments to form the spunbond web and transporting the spunbond web in a travel direction, at least one filament guide having a plurality of filament-guide gaps having stretcher side openings open toward the stretcher and provided between the stretcher and the deposition device, the filament guide having at least two guide parts extending transversely to the travel direction of the spunbond web and each forming a plurality of the filament-guide gaps aligned in a row transversely to the travel direction of the spunbond web, the filament-guide gaps of one of the guide parts being different from the filament-guide gaps of the other guide part, the two guide parts being movable back and forth in the travel direction of the spunbond web such that the filament-guide gaps of the one guide part and the filament-guide gaps of the other guide part are brought into or come into engagement with a filament curtain issuing from the stretcher in alternation, and means for moving the filament guide or the at least two guide parts thereof such that the filament-guide gaps or the stretcher-side openings thereof are displaced transversely to the travel direction of the spunbond web and filament bundles guided along or through the filament-guide gaps are given a transverse orientation to the travel direction of the spunbond web when deposited by the deposition device.

13. The apparatus according to claim 12, wherein the filament-guide gaps of the two guide parts are formed by plates and differ in terms of orientation and, inclination of the plates thereof.

14. The apparatus according to claim 1, wherein at least one guide surface extending transversely to the travel direction of the spunbond web is between the filament guide and the deposition device and at least one subregion of the guide surface is angled toward the deposition device.

15. The apparatus according to claim 1, wherein at least one guide surface extending transversely to the travel direction of the spunbond web is between the filament guide and the deposition device and is curved so as to form at least one constriction for conveying the filament bundles.

16. An apparatus for the continuous manufacture of a spunbond web and comprising: a spinneret downwardly emitting continuous filaments; a cooling chamber below the spinneret for cooling the filaments; a stretcher below the cooling chamber for aerodynamically stretching the cooled filaments and forming them into a curtain elongated horizontally in a transverse and horizontal direction; a conveyor surface downstream of the stretcher for receiving and conveying the stretched and cooled filaments in a horizontal and longitudinal travel direction generally perpendicular to the curtain away from the stretcher; a guide above the conveyor surface and below the stretcher and having a plurality of guide parts subdividing the curtain into a plurality of transversely spaced bundles; and means connected to the guide parts for transversely reciprocating the bundles so as to deposit the filaments transversely to the travel direction on the surface.

17. The apparatus defined in claim 16, wherein the guide includes: a shaft extending on an axis horizontally and transversely generally parallel to the curtain but offset in the travel direction therefrom, and a plurality of circular and planar disks forming the guide parts, fixed on the shaft, spaced transversely therealong, and lying in respective planes extending at an acute angle to the axis, the planes being generally parallel.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention is explained below in greater detail by reference to a drawing that depicts only one embodiment. In schematic depictions:

(2) FIG. 1 is a vertical section through an apparatus according to the invention,

(3) FIG. 2 is a perspective view of a guide part of a filament guide according to the invention,

(4) FIG. 3A is an enlarged detail from FIG. 1,

(5) FIG. 3B is another embodiment of the object according to FIG. 3A,

(6) FIG. 3C is a section through the guide part from FIG. 2 in a first position,

(7) FIG. 3D is a view like FIG. 3C but in a second position,

(8) FIG. 4 is another embodiment of the detail of FIG. 3A,

(9) FIG. 5 is a top sectional view of the structure of FIG. 4,

(10) FIG. 6 is another embodiment as in FIG. 3A,

(11) FIG. 7 is an additional embodiment as in FIG. 3A,

(12) FIG. 8A is a section through another embodiment of a filament guide according to the invention,

(13) FIG. 8B is the structure of FIG. 8A in another position, and

(14) FIG. 9 is a perspective view of an additional embodiment of a filament guide according to the invention.

SPECIFIC DESCRIPTION OF THE INVENTION

(15) FIG. 1 shows an apparatus for the continuous manufacture of a spunbond web S from aerodynamically stretched filaments of thermoplastic plastic. The apparatus has a spinneret 1 and a cooling chamber 2 underneath the spinneret and into which process air can be introduced in order to cool the filaments. Adjoining the cooling chamber 2 is an intermediate passage 3 followed in the direction of travel of the filaments, by a stretcher 4 having a stretching passage 5. Adjoining the stretching passage 5 is a deposition unit 6. A deposition device as a continuously circulating conveyor belt 7 for the deposition of the filaments for the spunbond web S is provided underneath the deposition unit 6. Here, the assembly comprising the cooling chamber 2, the intermediate passage 3, and the stretcher 4except for the air supply in the cooling chamber 2is a closed system. A further air supply is therefore not provided in this assembly.

(16) FIG. 1 also shows that an air supply chamber 8 next to the cooling chamber 2 and according to the embodiment is subdivided into an upper compartment 8a and a lower compartment 8b. Process air having different temperatures can be fed to the two compartments 8a and 8b and the filaments emerging from a nozzle plate 10 of the spinneret 1 are acted upon by this process air in the cooling chamber 2. Advantageously and in the embodiment according to FIG. 1, a monomer aspirator 27 is between the nozzle plate 10 and the cooling chamber 2 for extracting from the apparatus interfering gases emerging during the spinning process.

(17) It is also evident in FIG. 1 that the intermediate passage 3 has downstream converging walls, as viewed in the vertical section, from the outlet of the cooling chamber 2 to the inlet into the stretching passage 5 of the stretcher 4 and, in fact, advantageously and here, to the inlet width of the stretching passage 5. The stretcher 4 or the stretching passage 5 has for the filaments a stretching chute that extends transversely to the travel direction 23 of the spunbond web S and, in fact, advantageously at least across the greatest portion of the width of the deposited spunbond web S. A filament curtain F comprising the filaments emerges from the stretching chute and also extends transversely to the travel direction 23 of the spunbond web S.

(18) A filament guide 11 is between the stretcher 4 or between the stretching passage 5 and the conveyor belt 7, as shown in FIG. 1. According to one embodiment and in the embodiment according to FIG. 1, the filament guide 11 has a guide part 11a having a rotating shaft 16 explained in greater detail below. The filaments emerging from the stretching chute of the stretcher 4 as the filament curtain F are deflected transversely to the travel direction 23 of the conveyor belt 7 by the filament guide or by the shaft 16. Due to this deflection by the filament guide 11, the filaments undergo an additional transverse spreading (transversely to the machine direction) when deposited on the conveyor belt 7.

(19) In the embodiment according to FIG. 1, a deposition unit 6 having two guide surfaces 14a and 14b is underneath the filament guide 11. These guide surfaces 14a and 14b extend, advantageously and here, transverse to the travel direction 23 of the spunbond web S and, in fact, preferably along at least the greatest portion of the width of the spunbond web S. In the embodiment according to FIG. 1, the left guide surface 14a is flat and is angled toward the conveyor belt 7. The right guide surface 14b, however, is curved and has an upper section that converges toward a middle plane M, as well as a lower section that diverges away from the middle plane M. The deposition unit 6 according to FIG. 1 is also shown in FIG. 3A.

(20) FIG. 2 is a perspective view of a guide part 11a of the filament guide 11 having the rotating shaft 16. In the embodiment according to FIGS. 1, 3A and 3B, the filament guide 11 has only one such guide part 11a. In this connection, the rotation axis D of the shaft 16 is offset in each case to the left to the middle plane M or to the filament curtain F. According to a highly preferred embodiment and here, the shaft 16 carries a row of circular disks 17 that are fixed on the shaft 16. The disks 17 extend at a slant to the rotation axis D of the shaft and, preferably and here, are parallel to one another. Filament-guide gaps 12 for guiding or deflecting the filaments of the filament curtain F are formed between the disks 17. The filament-guide gaps 12 have upstream openings 13. When the shaft 16 rotates, these upstream openings 13 of the filament-guide gaps 12 shift transversely to the travel direction 23 of the spunbond web S. This can be seen, in particular, by comparing FIGS. 3C and 3D. When the shaft 16 rotates, filament bundles 21 each comprising a plurality of filaments are separated from of the filament curtain F. In this connection, each filament bundle 21 is advantageously accommodated entirely within a respective filament-guide gap 12 between the respective two disks 17. The filament bundles 21 in the filament-guide gaps 12 are shown in FIGS. 3C and 3D. The filament bundles 21 are deflected transversely to the travel direction 23 of the spunbond web S. The position of the shaft 16 in FIG. 3D differs from the position according to FIG. 3C in that the shaft 16 was rotated further by one-half of one rotation. As can be seen by comparing FIGS. 3C and 3D, the filament bundles 21 are deflected transversely to the travel direction 23 alternatingly in opposite directions when the shaft 16 rotates. When the shaft 16 rotates, a neutral position is also passed through in which the filament bundles 21 land on the conveyor belt 7 at the middle plane M without being deflected or substantially without being deflected. The rotation of the shaft 16 can therefore also be detected as an oscillation about the above-described neutral position. As explained above, when the shaft 16 moves or rotates, the filament-guide gap 12 or the upstream openings 13 thereof are displaced transversely to the travel direction 23 of the spunbond web S such that a transverse spreading to the travel direction 23 is imparted to the filaments or filament bundles 21 guided through the filament-guide gap 12 when they are deposited on the deposition device or on the conveyor belt 7. The shaft 16 has a diameter d and the disks 17 have a diameter D.sub.s in projection. In addition, the disks 17 are inclined at an angle ? to the rotation axis D of the shaft 16. Preferably and here, the disks 17 connected to the shaft 16 are parallel to one another with spacing s on both sides.

(21) FIGS. 3A and 3B show an embodiment in which the filament guide 11 according to the invention has only one guide part 11a having only one rotating shaft 16. As described above, the shaft 16 or the rotation axis D of the shaft 16 is offset from the middle plane M or offset from the filament curtain F. In fact, the rotation axis D has a spacing 1 from the middle plane M. The end of the stretching chute of the stretching passage 5 is set at a spacing a from the conveyor belt 7 and the rotation axis D of the shaft 16 is at a spacing b from the conveyor belt 7. FIG. 3A shows the above-described deposition unit 6 of the embodiment according to FIG. 1. FIG. 3B, however, shows another deposition unit 6 having only one guide surface 14b whose cross-section is part-cylindrical and that also extends transversely to the travel direction 23 of the spunbond web S.

(22) FIG. 4 shows another embodiment of a filament guide 11 according to the invention. Two guide parts 11a and 11b are provided here, each of which has a rotating shaft 16 extending transversely to the travel direction of the spunbond web S. The rotation axes D of the two shafts 16 are at the same vertical level here. In this embodiment, the disks 17 of one shaft 16 engage into spaces between the disks of the other shaft 16. This is shown particularly clearly in the top view according to FIG. 5. A filament-guide gap 12 is formed here between each disk 17 of one shaft 16 and a respective disk 17 of the other shaft 16. In this embodiment, the disks 17 of the shafts 16 mesh with one another. The two shafts 16 can rotate in the same or the opposite direction. The rotation can be clockwise or counterclockwise. In this embodiment (FIG. 4) and in the embodiments according to FIGS. 6 and 7 described below, the deposition unit 6 is a diffuser. In this connection, preferably and here, two guide surfaces 14a and 14b curved symmetrically to the middle plane M are provided between the filament guide 11 and the conveyor belt 7. These curved guide surfaces 14a and 14b form an upper converging region and a constriction adjacent thereto, as well as a subsequent region diverging toward the conveyor belt 7.

(23) The embodiment according to FIG. 6 also has two guide parts 11a and 11b that each have a rotating shaft 16. Here, the two shafts 16 or the rotation axes D thereof are spaced such the disks 17 of one shaft 16 do not engage into spaces between the disks of the other shaft. The filaments are guided between the rotation axes D of the two shafts 16.

(24) In the embodiment according to FIG. 7, two rotating shafts 16 or the rotation axes D thereof are at different vertical levels or the rotation axes D are in different horizontal planes. Both shafts are also offset from the middle plane M or from the filament curtain F and the filaments are guided between the rotation axes D of the two shafts 16. In the embodiments according to FIG. 6 and FIG. 7 as well, the two shafts can rotate in the same direction or in opposite directions. The rotation can be clockwise or counterclockwise.

(25) FIGS. 8A and 8B show an alternative embodiment of a filament guide 11 according to the invention. The filament guide 11 here has a plurality of rotating shafts 16 extending in the travel direction 23 of the spunbond web S. A disk 17 extending longitudinally of the shaft is connected to each shaft 16. Preferably and here, the shafts 16 each rotate back and forth through a predetermined angle about the respective rotation axis D. As a result, the filament-guide gaps 12 or the upstream openings 13 thereof between the disks 17 are displaced transversely to the travel direction 23 of the spunbond web S. Due to this displacement, the filaments or filament bundles 21 of the filament curtain F are deflected transversely to the travel direction 23 of the spunbond web S. This can be seen by comparing FIGS. 8A and 8B. FIG. 8A shows a neutral position of the shafts 16 or the disks 17 thereof. The disks 17 oscillate about this neutral position and, as a result of these oscillations or back-and-forth rotation movements, the filaments are deflected transversely to the travel direction 23.

(26) In the embodiment shown in FIG. 9, the filament guide 11 has two guide parts 11a and 11b extending transverse to the travel direction 23 of the spunbond web S and each having a plurality of filament-guide gaps 12 aligned in a row transversely to the travel direction 23. These filament-guide gaps 12 are formed between plates 22 that are angled to the filament curtain F or to the middle plane M and that are connected to guide bars 24 oriented transverse to the travel direction 23. The plates 22 of the two guide parts 11a and 11b are angled in opposite directions or are at a slant or are oriented so as to be offset from one another. The two guide parts 11a and 11b are moved back and forth in the travel direction 23 such that the filament-guide gap 12 of one guide part 11a and the filament-guide gap 12 of the other guide part 11b alternately engage with the filament curtain F. In turn, filament bundles 21 are separated from the filament curtain F and are deflected transversely to the travel direction 23. These guide parts 11a and 11b also move or oscillate about a neutral position in which there is no deflection or substantially no deflection of the filaments or filament bundles 21. The back-and-forth movement or oscillation of the guide parts 11a, 11b alternately deflects the filament bundles 21 in one direction or in the direction opposite thereto, transversely to the travel direction 23.

(27) The invention is explained in greater detail below with reference to the embodiments:

(28) The table lists parameters and measurement results for embodiments 1 to 4 according to the teaching according to the invention and by comparison with comparative examples V1 and V2 without the filament guide 11 according to the invention. An apparatus according to FIG. 1 was used in every case, where the individual embodiments or comparative examples differ merely in terms of the design of the filament guide unit 11 and the deposition unit 6 between the stretcher 4 and the conveyor belt 7. In embodiments 1 to 3, the region between the stretcher 4 and the conveyor belt 7 was designed as shown in FIG. 3B. Here, a shaft 16 offset from the middle plane M is provided and there is a curved guide surface 14b offset from the middle plane M. In embodiment 4, the region between the stretcher 4 and the conveyor belt 7 is designed according to FIG. 3A. Here, a shaft 16 disposed so as to be offset and two guide surfaces 14a, 14b (according to FIG. 3A) located thereunder were therefore provided. In the comparative example V2, work was performed with the deposition unit 6i.e. with the guide surfaces 14a and 14b-according to FIG. 3A, but without the shaft 16. In the comparative example V1, a so-called REICOFIL IV diffuser was inserted between the stretcher 4 and the conveyor belt 7, wherein the diffuser is shown in FIG. 3 of EP 1 340 843 [U.S. Pat. No. 6,918,580]. Work was carried out without a filament guide 11 or a shaft 16 here as well.

(29) The second column of the table lists the basis weight, in g/m.sup.2, of the spunbond web that is obtained and the third column of the table lists the line speed or the conveyance speed of the spunbond web S in m/min. The fourth column of the table lists the thermoplastic plastic or raw material that is used for the filaments or for the manufacture of the spunbond web S, i.e. polypropylene with the associated melt flow rate MFR for the embodiments 1 to 3 and for the comparative examples V1 and V2. Bicomponent filaments having a core-sheath configuration were used in embodiment 4 where the core comprised polyethylene terephthalate (PET) and the sheath comprised a copolymer of PET. The other columns of the table list the spacing a between the end of the stretcher 4 and the conveyor belt 7, the spacing b between the rotation axis D of the shaft 16, the conveyor belt 7, and the spacing I of the rotation axis D from the middle plane M. The subsequent columns list the diameter d of the shaft 16 that is used, as well as the diameters D.sub.s of the disks 17 in the projection and the spacing s between the disks, as well as the angle ? that the disks 17 form with the rotation axis D. The subsequent columns show the tensile strength in the machine direction (MD) in N/5 cm and the tensile strength transverse to the machine direction (CD) in N/5 cm for the individual examples. The tensile strengths were measured according to EDANA 20.2-89. This is followed by a column listing the corresponding MD/CD ratio. The two final columns relate to the rotating shaft 16. The second-to-last column lists the rotation speed of the shaft and the final column lists the type of drive for the shaft 16. In embodiments 1 to 3 the rotating shaft 16 was driven merely by the flowing process air. In embodiment 4, however, an electric motor was used to drive the shaft 16. It is understood that no parameters or information related to the shaft 16 are provided in the comparative examples V1 to V2, since neither a filament guide 11 nor a shaft 16 were used here, as is known.

(30) A comparison of the embodiments 1 to 4, which were carried out with the filament guide 11 according to the teaching according to the invention, with the comparative examples V1 and V2 (without the filament guide 11), shows that, as compared to the comparative examples, the spunbond webs S produced according to the invention have an improved tensile strength in the transverse direction (CD), in particular, to the basis weight thereof. The spunbond webs S produced according to the invention are therefore characterized by considerable advantages. With regard to the comparative examples, it should be noted that the spunbond web according to comparative example V1, which was produced without the shaft, has filaments that were deposited in a relatively uniform or homogeneous manner and is also characterized by relatively favorable strength values, even if these strength valuesin particular to the basis weight of the spunbond fabricare not as optimal as they are with the spunbond webs produced according to the invention. In the comparative example V2without the Reicofil 4 diffuserthe filaments are deposited in a relatively nonuniform manner, however, and markedly lower strength values are obtained.

(31) TABLE-US-00001 Basis Line Raw No. weight speed material a b l d D.sub.a Alpha s 1 55 gsm 50 m/min. PP MFR 1600 mm 1200 mm 120 mm 100 mm 300 mm 30? 100 mm 19 2 55 gsm 50 m/min. PP MFR 1600 mm 1200 mm 100 mm 100 mm 300 mm 30? 100 mm 19 3 55 gsm 50 m/min. PP MFR 1600 mm 1200 mm 75 mm 100 mm 300 mm 30? 100 mm 19 4 100 gsm 47 m/min. Pet/ 800 mm 500 mm 150 mm 200 mm 400 mm 25? 100 mm CoPET core/ sheath IV 0.63 V1 65 gsm 51 m/min. PP MFR no shaft 16 25 V2 65 gsm 48 m/min. PP MFR no shaft 16 19 Number of N/5 cm N/5 cm Shaft Drive No. guide surfaces in MD in CD MD/CD speed type 1 1 187 164 1.14 1030 air 2 1 176 162 1.09 1150 air 3 1 146 188 0.78 1111 air 4 2 291 357 0.82 1200 active/ e-motor V1 Reicofil 4 195 162 1.21 diffuser V2 2 174 143 1.22