Device for the Extrusion of Filaments and for the Production of Spunbonded Fabrics
20200291545 · 2020-09-17
Inventors
Cpc classification
D04H1/56
TEXTILES; PAPER
B29K2001/00
PERFORMING OPERATIONS; TRANSPORTING
B29L2031/731
PERFORMING OPERATIONS; TRANSPORTING
D01F2/00
TEXTILES; PAPER
D04H3/16
TEXTILES; PAPER
International classification
B29C48/14
PERFORMING OPERATIONS; TRANSPORTING
D01F2/00
TEXTILES; PAPER
Abstract
A device (1) for the extrusion of filaments (2) comprising a plurality of extrusion capillaries (3) arranged in at least two consecutive rows and having extrusion openings (4) for extruding a spinning solution, whereby the filaments (2) are formed, and a plurality of components (7, 8, 10) for the generation of a gas stream for producing a gas stream oriented essentially in the direction of the extrusion of the filaments (2) at least in the area of the extrusion openings (4), wherein the extrusion capillaries (3) are arranged in extrusion columns (6) which protrude from a base plate (5) and are formed in one piece with said base plate (5).
Claims
1. A device for the extrusion of filaments comprising a plurality of extrusion capillaries arranged in at least two consecutive rows and having extrusion openings for extruding a spinning solution, whereby the filaments are formed, and a plurality of components for the generation of a gas stream for producing a gas stream oriented essentially in the direction of the extrusion of the filaments at least in the area of the extrusion openings, wherein the extrusion capillaries are arranged in extrusion columns which protrude from a base plate and are formed in one piece with said base plate.
2. The device according to claim 1, wherein the components for the generation of a gas stream include at least two gas supply openings, which are arranged adjacent to the base plate, are located opposite to each other and are configured so as to produce a gas stream oriented essentially vertically to the direction of the extrusion of the filaments in the area of the gas supply openings.
3. The device according to claim 1, wherein the external geometry of the extrusion columns is cylindrical, conical, cuboidal, obelisk-shaped, pyramid-shaped or mixtures thereof.
4. The device according to claim 1, wherein the extrusion capillaries exhibit an inlet section the geometry of which differs from that of the remaining sections of the extrusion capillary.
5. The device according to claim 4, wherein the geometry of the inlet section is cylindrical, conical, square, rectangular, circular, elliptical and mixtures thereof.
6. The device according to claim 1, wherein the geometry of the extrusion openings is circular, elliptical, triangular, square, rectangular, T-shaped, H-shaped, U-shaped, Y-shaped or Z-shaped.
7. The device according to claim 1, wherein at least part of the extrusion columns differs from another part of the extrusion columns in at least one property selected from the length of the extrusion column the external geometry of the extrusion column the external diameter of the extrusion column the existence of an inlet section of the extrusion capillary the geometry of the inlet section the geometry of the extrusion openings.
8. The device according to claim 1, wherein the components for the generation of a gas stream optionally include, in addition, gas outlet openings arranged in the area of the extrusion openings and designed for the production of a gas stream oriented in the direction of the extrusion or, in case that gas supply openings are provided adjacent to the base plate, configured for discharging the gas stream in the direction of the extrusion.
9. The device according to claim 8, wherein the device comprises a gas outlet plate, with the gas outlet openings being formed in the gas outlet plate.
10. The device according to claim 9, wherein the gas outlet plate is formed in one piece with the base plate and the extrusion columns.
11. The device according to claim 1, wherein the device has an essentially rectangular basic shape.
12. The device according to claim 1, wherein one extrusion capillary is provided per extrusion column.
13. The device according to claim 1, wherein the device comprises at least one extrusion column in which two or more extrusion capillaries are provided.
14. The use of a device according to claim 1 for the extrusion of filaments and for the production of spunbonded fabrics from various polymeric materials.
15. The method of producing a device according to claim 1, comprising the step of manufacturing the base plate, the extrusion columns and optionally the gas supply openings as well as optionally the gas outlet plate by forming them jointly in one piece from a base material.
16. The use according to claim 14, wherein the various polymeric materials are from melts of thermoplastics such as polypropylene, polystyrene, polyester, polyurethane, polyamide, EVA, EMA, EVOH, fusible copolymers, PBT, PPS, PMP, PVA, PLA or Lyocell spinning dope.
17. The use according to claim 16, wherein the polymeric material is a Lyocell spinning dope.
Description
[0021] To better illustrate the invention, the essential features are shown in the following figures on the basis of preferred embodiments of the device according to the invention:
[0022]
[0023]
[0024]
[0025]
[0026]
[0027]
[0028]
[0029]
[0030]
[0031]
[0032] The means 7, 8, 10 for the generation of a gas stream include a gas flow distributor 8, which is not illustrated further, and at least two gas supply openings 7, which are arranged adjacent to the base plate 5. According to a further embodiment of the device, the means for the generation of a gas stream also include gas outlet openings 10, which are illustrated in
[0033]
[0034] It has been shown that the device 1 according to the invention as shown in
[0035] Surprisingly, it has been shown that the production of nonwoven fabrics from melts and solutions works with the present invention also without gas flow outlet plates (which are necessary in prior art devices). The external geometry of the extrusion columns 6 and their arrangement with respect to each other, i.e., the shape of the gas flow duct 9 resulting therefrom, is sufficient for redirecting the gas stream, for accelerating it and for drawing the extruded filaments 2.
[0036] According to the invention, support plates are not required, either, since the extrusion columns 6 are stable enough and cannot be bent or caused to vibrate by the gas stream.
[0037] The melt or, respectively, the solution enters into the extrusion capillary 3 and flows as far as to the extrusion opening 4. At the same time, a gas stream is supplied on both longitudinal sides of the device 1 via the gas flow distributor 8 and the gas supply openings 7 essentially vertically to the direction of the extrusion of the filaments. The gas stream is guided through the gas flow duct 9 formed between the extrusion columns 6. Since the gas streams collide from the two sides, they are guided and accelerated along the extrusion columns 6 toward the extrusion opening 4. Upon exiting the extrusion capillary 3, the extruded melt or, respectively, solution filament is entrained and drawn by the hot gas stream at high speed. Because of the turbulence of the gas stream, the drawn filaments 2 are placed in a random arrangement and deposited as a nonwoven fabric on a drum or, respectively, on a conveyor belt (not illustrated).
[0038] An advantage of the device 1 is that, in contrast to a needle nozzle, it can be manufactured from the base material in one piece or, respectively, from a base material block, and that no long, thin tubes need to be inserted into a plate and welded or glued in a complicated way. The gas flow ducts 9 are removed mechanically, for example, and this results simultaneously in the extrusion columns 6. This simplifies the manufacture of the device 1 and increases stability. As a result, the manufacture and installation of support plates is not necessary, either. Moreover, there is no longer the risk of needles being bent during the manufacture or assembly of the device 1.
[0039] Via the gas flow ducts 9, the gas stream entering via the gas flow distributor 8 is guided and accelerated toward the extrusion opening 4. Surprisingly, it has been shown that this deflection through the gas flow ducts 9 at 0.1 to 3 bar, preferably at 0.3 to 1.5 bar, more preferably at 0.5 to 1.0 bar, gas stream pre-pressure, leads to speeds of 20 to 250 m/s at the extrusion opening 4, without the need of using a gas flow outlet plate. As a result, also nonwoven fabrics can be produced with the device 1 without conveying the gas through a gas flow outlet plate 11. Thus, a further nozzle part can be omitted so as to reduce the effort associated with manufacturing, assembling and operating the device 1.
[0040] In addition, a gas outlet plate 11 is provided in
[0041] As shown in
[0042] In one embodiment of the device 1, the gas outlet plate 11 is thereby formed in one piece with the base plate 5 and the extrusion columns 6. These are, in turn, manufactured from the base material in one piece.
[0043] The device 1 manufactured in accordance with one of the previously described embodiments is fastened at the top to a melt or, respectively, solution distributor. The connection of the gas flow distributor 8 to the gas flow supply line may occur either on the longitudinal sides, on the broadside, or on the upper side of the device 1. Since the device 1 consists of a solid piece of base material, heating systems (e.g., hot water, oil, steam, electric heaters, . . . ) can also be installed with little effort in order to improve the spinning stability and to increase the consistency of the quality of the nonwoven fabric.
[0044] The gas flow supply via the gas flow distributor 8 to the extrusion columns 6 takes place uniformly over the two longitudinal sides of the device 1, as shown in
[0045] Many geometries and variations are possible for the production of the section or the sections. The extrusion capillaries 3, which are not illustrated in
[0046] Part of the gas stream emerging from the gas flow distributor 8 via the gas supply openings 7 impinges on the first row of extrusion columns and is deflected toward the extrusion opening 4. The remainder of the gas stream flows in the gas flow duct 9 between the extrusion columns 6 in the inner rows until it impinges on the gas stream from the other device side. This apparently creates a congestion cone which guides the gas stream along the inner rows of extrusion columns as far as to the extrusion outlet. This deflection effect already works with one row of extrusion columns. The number of rows of extrusion columns that can be supplied with the gas stream without the need for an additional gas outlet plate 11 ranges, for example, between one and thirty rows, preferably between two and twenty rows, more preferably between three and eight rows, depending on the extrusion column design and the gas duct width. In addition to the examples mentioned, further geometries, combinations of said geometries and different geometries are possible for the device 1.
[0047]
[0048] In order to promote the deflection of the gas stream, the external geometry and the arrangement of the extrusion columns 6, as illustrated in
[0049] The extrusion columns 6 may have either equal or different lengths in order to produce variations in the fineness of the fibers.
[0050] The length of an extrusion column 6 from foot to tip may be between 10 mm and 200 mm, preferably between 20 mm and 100 mm, more preferably between 30 mm and 60 mm. For cylindrical extrusion columns 6, the external diameter, depending on the internal geometry of the extrusion capillary 3 and the length of the extrusion column 6, may be between 3 mm and 30 mm, preferably between 6 mm and 20 mm, more preferably between 9 mm and 15 mm. For conical extrusion columns 6, the diameter of the footprint may be between 3 mm and 30 mm, preferably between 6 mm and 20 mm, more preferably between 9 mm and 15 mm. The tip of the cone can taper to a diameter of 0.1 mm. In cuboidal extrusion columns 6, obelisks and pyramids, the side length is between 3 mm and 30 mm, preferably between 6 mm and 20 mm, more preferably between 9 mm and 15 mm. In addition to the examples mentioned, further geometries, combinations of said geometries and different geometries are possible for the device 1.
[0051] The extrusion columns 6 can additionally be heated or cooled in order to improve the spinning stability.
[0052]
[0053] As per a preferred embodiment of the device 1 according to the invention, one extrusion capillary 3 is provided per extrusion column 6. In an alternative embodiment, the device 1 has at least one extrusion column 6, in which two or more extrusion capillaries 3 are arranged. The device 1 shown in
[0054] In principle, embodiments with a high number of extrusion capillaries 3 per extrusion column 6 are possible as well. In this way, the advantage is obtained that the device is suitable for the production of a plurality of different spunbonded webs from a wide variety of materials.
[0055]
[0056] Since the extrusion columns 6 occupy more space than, for example, the needles of a multi-row needle nozzle of the prior art, the throughput per hole must be much higher in order to achieve the necessary throughputs. For this, the geometry of the extrusion capillary 3 must be adapted to the rheological properties of the materials used.
[0057] According to a further embodiment of the device 1, at least one extrusion capillary 3 has, for example, two or more extrusion openings 4, as shown by way of example in
[0058]
[0059]
[0060]
[0061] According to an embodiment of the device 1, at least part of the extrusion columns 6 of the device 1 according to the invention may differ from another part of the extrusion columns 6 in at least one property selected from the length of the extrusion column 6, the external geometry of the extrusion column 6, the external diameter of the extrusion column 6, the existence of an inlet section 12 of the extrusion capillary 3, the geometry of the inlet section 12 and the geometry of the extrusion openings 4.
[0062] In a further embodiment, the device 1 has a substantially rectangular basic shape. As a result, productional advantages are achieved.
[0063]
[0064] The invention as described was an improvement over known nozzles in terms of production expenditure, variety of design, throughput, assembly, scalability to large lengths, and operation. As raw materials, the polyolefins already used for other meltblown processes can be used as homopolymers and co-polymers (e.g., EVA), as well as terpolymers, polyesters, polyamides, polyvinyls, nylon, PC, and other suitable raw materials. Polyolefins such as PP, PE, LDPE, HDPE, LLDPE are used preferably as homopolymer or co-polymer. Cellulose acetate, starch solutions and Lyocell solutions may also be used with the present invention and the above-mentioned advantages for the production of filaments and spunbonded fabrics.
[0065] The device 1 can thus be used for the extrusion of filaments 2 and for the production of spunbonded webs from a wide variety of polymeric materials. These include in particular melts of thermoplastics such as polypropylene, polystyrene, polyester, polyurethane, polyamide, EVA, EMA, EVOH, fusible copolymers, PBT, PPS, PMP, PVA, PLA or Lyocell spinning dope, the use of Lyocell spinning dope being particularly preferred.
[0066] The generic name Lyocell has been awarded by BISFA (The International Bureau for the Standardisation of Man Made Fibres) and denotes cellulose fibres made from solutions of cellulose in an organic solvent. Tertiary amine oxides, in particular N-methyl-morpholine-N-oxide (NMMO), are preferably used as solvents. A method of producing Lyocell fibres is described, for example, in U.S. Pat. No. 4,246,221 A. Other possible solvents are often summarized under the collective term ionic liquids.
[0067] As already mentioned, in the production of nonwoven fabrics with the device 1, the melt or, respectively, the solution is pumped through the device 1, drawn with hot air and deposited as a nonwoven fabric on a drum or a conveyor belt. Depending on the raw material, the produced nonwoven material can either be wound up directly, or it must first be washed, aftertreated and dried. Depending on the raw material used, the design of the present invention can be adapted such that temperatures between 20 C. and 500 C., preferably from 50 C. to 400 C., more preferably between 100 C. and 300 C., can be operated as long as the raw material and the produced nonwoven material are not damaged by the temperature. According to the invention, the device 1 can have such a solid design that, on the part of the melt, pressures between 10 bar and 300 bar, preferably between 20 bar and 200 bar, more preferably between 30 bar and 150 bar, can take effect. The throughputs of the melt or, respectively, the solution and of the gas stream required for the production of the nonwoven material can vary greatly depending on the raw material used, the distance between the device 1 and the depot, the nozzle design and the applied temperature. The usual throughput of the melt or, respectively, the solution per extrusion hole ranges from 1 g/hole/min to 30 g/hole/min, preferably from 2 g/hole/min to 20 g/hole/min, more preferably between 3 g/hole/min and 10 g/hole/min. For a device 1 with a length of 1 m, 6 rows and 100 gaps, this corresponds to a throughput of 1080 kg/h/m. As a result, the throughput of the device 1 is higher than in the needle nozzle and much higher than in the single-row nozzles. The usual range for the amount of the gas stream in kg of gas per kg of melt or, respectively, solution is between 10 and 300 kg/kg, preferably from 20 kg/g to 200 kg/kg, more preferably between 30 kg/kg and 100 kg/kg. Since the device 1 can be constructed with a length of up to 5 m and beyond, nonwoven widths of 5 m and beyond can be achieved. Depending on the design of the device, the raw material and the operating parameters, the manufactured products have fibre diameters of 1 m to 30 m, preferably 2 m to 20 m, more preferably between 3 m and 10 m. Depending on the throughput and the transport speed, nonwoven fabrics with a weight per unit area of between 5 g/m.sup.2 and 1000 g/m.sup.2, preferably between 10 g/m.sup.2 and 500 g/m.sup.2, more preferably between 15 g/m.sup.2 and 200 g/m.sup.2, can be produced with the device according to the invention.
[0068] The device 1 according to the invention for the extrusion of filaments 2 is produced in a method which comprises the step of manufacturing the base plate 5, the extrusion columns 6, optionally the gas supply openings 7 and furthermore optionally the gas outlet plate 11 by forming them jointly in one piece from a base material.