Title of Invention	AN APPARATUS FOR THE MANUFACTURE OF A SPUNBOND WEB MADE OF FILAMENTS
Abstract	An apparatus for the manufacture of a spunbond web from filaments wherein a spinneret for producing filaments is provided. Downstream of the spinneret is a cooling chamber into which the process air is fed to cool the filaments. A stretching unit for stretching the filaments is connected to the cooling chamber, and the connection region between the cooling chamber and the stretching unit is closed. This stretching unit has a stretching passage whose passage walls diverge over at least a part of the length of the stretching passage. A depositing device for the deposition of the filaments for the spunbond web is provided.

Title of Invention

AN APPARATUS FOR THE MANUFACTURE OF A SPUNBOND WEB MADE OF FILAMENTS

Abstract

An apparatus for the manufacture of a spunbond web from filaments wherein a spinneret for producing filaments is provided. Downstream of the spinneret is a cooling chamber into which the process air is fed to cool the filaments. A stretching unit for stretching the filaments is connected to the cooling chamber, and the connection region between the cooling chamber and the stretching unit is closed. This stretching unit has a stretching passage whose passage walls diverge over at least a part of the length of the stretching passage. A depositing device for the deposition of the filaments for the spunbond web is provided.

Full Text	Description: The invention relates to an apparatus for the manufacture of a spunbond web made of filaments. The filaments consist typically of a thermoplastic resin. An apparatus of the above-mentioned type is known in different embodiments that are used in practice. The filaments are spun first with the help of a spinneret, and then are usually passed through a cooling chamber. After cooling, the filaments or the filament bundle reach a stretching passage of a stretching unit in which they are stretched aerodynamically. The transverse width of the stretching passage in the machine or travel direction of the spinning fleece is here normally 10-20 mm. Because of this relatively small dimension, the filament bundle in the stretching unit is compacted relatively strongly. This has the disadvantage, in many known installations, that the filaments can be separated only with considerable difficulty and deposited as individual filaments. The object of the invention is to provide an apparatus of the type mentioned above by means of which the filament bundle produced can be separated in a simple and effective manner into individual filaments that can then be deposited for the spunbond web. To attain this object, the invention proposes an apparatus for the continuous manufacture of a spunbond web from filaments, wherein a spinneret for producing the filaments is provided, downstream of the spinneret is a cooling chamber that is supplied with process air to cool the filaments, a stretching unit for stretching the filaments is connected to the cooling chamber, a connection region between the cooling chamber and the stretching unit is closed, the stretching unit has a stretching passage whose passage walls diverge over at least a part of the length of the stretching passage, and a depositing device for the deposition of the filaments for the spunbond web is provided. A spinneret is in particular a spinneret that spins the filaments. The spun filaments are then fed through the cooling chamber in which the cooling of the filaments takes place. It is within the scope of the invention that the cooling chamber is a closed chamber that, in addition to the process air intake, and in addition to the inlet opening and outlet opening for the filament band, is closed or substantially closed. According to the invention, the connection region between the cooling chamber and the stretching unit is closed. In the connection region or the transition region between the cooling chamber and the stretching unit there is thus, according to the invention, no air feed or substantially no air feed into the system or into the flow path of the filaments. In the context of the invention, a diverging design of the passage walls of the stretching passage means in particular that the passage walls are arranged/designed to diverge transversely to the machine direction or transversely to the spunbond web. The spacing between these passage walls increases in the diverging section in the direction toward the depositing device. The length of the stretching passage moreover means the extent of the stretching passage between the cooling chamber and the depositing device. The diverging part of the stretching passage is also referred to below as the diverging stretching passage section or in brief as the diverging section. A greatly preferred embodiment of the invention is characterized in that the cooling chamber is subdivided into at least two cooling compartments, in which the filaments in each case can be cooled with process air at a different temperature. This special embodiment has been found to be particularly advantageous in the scope of the invention. According to an embodiment, the temperature of the fed process air in the upstream upper cooling compartment is higher than the temperature of the fed process air in the lower downstream cooling compartment. The upstream upper cooling compartment here relates to the cooling compartment into which the filaments enter first. According to the invention, the connection region between the cooling chamber and the stretching unit is closed. The stretching unit is thus connected to the cooling chamber with the condition that no introduction of air or substantially no introduction of air takes place in the connection region between the cooling chamber and the stretching unit. The stretching unit can here be connected directly to the cooling chamber without any air-feed slit. According to a third embodiment of the invention, an intermediate passage is arranged between the cooling chamber and the stretching unit. Here, the fact that no air is introduced from the outside or substantially no air is introduced from the outside into this intermediate passage falls within the scope of the invention. This means that only the process air from the cooling chamber is introduced into the intermediate passage and that otherwise no air introduction or substantially no air introduction from the outside takes place. It is preferred for the intermediate passage to have a converging shape from the cooling chamber to the stretching unit. Here, the intermediate passage walls, which are spaced transversely to the machine direction or transversely to the travel direction of the spunbond web, converge. The intermediate passage thus narrows from the cooling chamber to the stretching unit. According to an embodiment of the invention, different convergence angles of the intermediate passage can be used. The fact that the lower end of the intermediate passage is connected to the stretching passage of the stretching unit without an intake slit for air or substantially without an intake slit for air falls within the scope of the invention. Thus, only the process air (with the filament), and no additional air or substantially no additional air, reaches the stretching passage from the intermediate passage. However, it is recommended that in the stretching unit, at the upstream end of the diverging stretching passage section or slightly upstream of the diverging stretching passage section, additional air is injected into the stretching passage. Here, the air is advantageously injected parallel to the travel direction of the filaments or the filament bundle, and preferably tangentially to the filament bundle. The air is blown in tangentially and preferably as a boundary layer. It is recommended that the air injection be from opposite facing passage walls or facing diverging passage walls of the stretching passage and, here, preferably at the same height with respect to the length of the stretching passage. Such a two-sided air feed can also take place twice or repeatedly at different heights of the stretching passage. The air injection takes place advantageously with the condition that the filament bundle is made broader in the machine direction or in the travel direction of the spunbond web. In this process, it is preferred to operate in such a way that the opening angle of the filament bundle is 0.1-10°, preferably 0.1-1°. The expression "at the upstream end of the diverging stretching passage section" means in particular the upstream third, preferably the upstream fourth, and particularly preferably the upstream fifth of the diverging stretching passage section, with respect to the length of the diverging stretching passage section. The spacing between the passage walls of the stretching passage is advantageously 5-30 mm, preferably 8-25 mm, and preferably 10-20 mm. It is within the scope of the invention that at least one fourth, preferably at least one third of the length of the stretching passage diverges or is designed as a diverging section. At least 40% of the length of the stretching passage is preferably diverging or has a diverging flow cross section. According to a first preferred embodiment of the invention, the stretching passage has diverging passage walls over its entire length or substantially over its entire length. According to this embodiment, the entire stretching passage or substantially the entire stretching passage diverges. It falls within the scope of the invention for the stretching passage to diverge over at least 90%, preferably over at least 95% of its length. According to an additional preferred embodiment of the invention, the stretching passage has over a part of its length parallel passage walls (parallel section) and downstream of this part are diverging passage walls (diverging section). Here, it falls within the scope of the invention that the stretching passage in this embodiment consists exclusively of the mentioned parallel section and the downstream diverging section. The additional air feed takes place in this embodiment either at the end of the parallel section or at the upstream end of the diverging section of the stretching passage. The end of the parallel passage here refers in particular to the downstream third with respect to the length of the parallel section, preferably the farthest downstream fourth, and most preferably the farthest downstream fifth of the parallel section. The upstream end of the diverging section here and below means in particular the farthest upstream third with respect to the length of the diverging section, preferably the farthest upstream fourth, and most preferably the farthest upstream fifth of the diverging section. It is preferred for the diverging section of this embodiment to be longer than the parallel section, the diverging section being advantageously at least 1.5 times the length of the parallel section. According to a preferred embodiment of the invention, the stretching passage has converging passage walls (converging section) over part of its length, which are then ed by diverging passage walls (diverging section). Here, it falls within the scope of the invention that the stretching passage in this embodiment consists exclusively of the converging and the diverging section. Thus, the diverging section is immediately downstream of the converging section. In this embodiment, the additional air feed is advantageously in the transitional region between the converging section and the diverging section, or at the upstream end of the diverging section. It is advantageous in this embodiment for the diverging section to be longer than the converging section, and the diverging section is preferably 1.5 times the length of the converging section. According to an additional embodiment of the invention, the stretching passage has over a part of its length converging walls (converging section), downstream of which are parallel passage walls (parallel section), and downstream of which in turn are diverging passage walls (diverging section). According to an embodiment, the stretching passage here consists exclusively of the converging section, the next downstream parallel section, and in turn the next downstream diverging section. However, in principle, the last-mentioned diverging section can also be a downstream parallel section. In this embodiment, the additional air feed takes place advantageously at the end of the (upstream) parallel section or at the upstream end of the diverging section. The end of the parallel section means the farthest downstream third, preferably the farthest downstream fourth, and most preferably the farthest downstream fifth of the parallel section, with respect to the length of the parallel section. In this embodiment (converging-parallel-diverging), it is recommended for the diverging section to be the longest passage section. This means that the diverging section in each case is longer than the parallel section and longer than the convergent section. According to a particularly recommended embodiment, the diverging section is longer than the total passage section consisting of the converging and parallel section. According to a preferred embodiment of the invention, the diverging passage walls of the diverging section are in an arrangement that is symmetric with respect to a middle plane that runs vertically through the stretching passage. In principle, the scope of the invention also includes that the diverging passage walls can be arranged asymmetrically with respect to this middle plane. In that case, one of the two diverging passage walls would thus have a stronger inclination or slanted position than the other facing passage wall. According to a preferred embodiment of the invention, the divergence angle of the diverging section remains constant over the length of the diverging section. However, in principle, it is also possible for the divergence angle to change over the length of the diverging section. it falls within the scope of the invention that the cooling chamber and the stretching unit of the apparatus according to the invention form a closed unit. Here, air feed into the aggregate consisting of the cooling chamber and the stretching unit is limited at least substantially to the introduction of the process air into the cooling chamber, on the one hand, and to the additional air fed in upstream of the diverging section or at the upstream end of the diverging section in the stretching passage, on the other hand. Naturally, air can also reach the cooling chamber from above with the deposition belt. A particular embodiment, which is particularly important within in the scope of the invention, is characterized in that downstream of the stretching unit a repositioning unit with at least one diffuser. Thus, the filaments are, or the filament bundle is, led through at least one diffuser after the stretching unit. The diffuser has at least regions with diverging diffuser walls. The diffuser walls are here spaced transversely to the machine direction or transversely to the travel direction of the spunbond web. According to a recommended embodiment, the repositioning unit consists of an upstream diffuser and a next downstream diffuser. It is advantageous to provide an ambient air inlet slit between the upstream diffuser and the downstream diffuser. Because of the exit pulse from the upstream diffuser, air is sucked out of the environment through this ambient air inlet slit. The width of the ambient air inlet slit is advantageously adjustable. It falls within the scope of the invention that the depositing device of the apparatus according to the invention is a continuously moving foraminous deposition belt for the spunbond web. At least one suction apparatus is advantageously provided under the foraminous deposition belt, by means of which air can be sucked through the foraminous deposition belt. The invention is based on the discovery that qualitatively a very high quality spunbond web can be manufactured with the apparatus according to the invention, which is characterized particularly by a homogeneous structure and homogeneous properties. The invention is based particularly on the discovery that, as a result of the design of the stretching unit according to the invention, an undesired compaction of the filament bundle can be avoided or any compaction that has already occurred can be reduced greatly. The treatment according to the invention of the filament bundle can result in an effective spacing between the individual filaments. Thus, with the design according to the invention, a high number of filaments can be deposited in the form of individual filaments. As a result, the quality of the spunbond web manufactured according to the invention can be increased considerably in comparison to a spunbond web manufactured according to the prior art. Moreover, it should be emphasized that the success according to the invention can be achieved using relatively simple and cost effective measures. As a result, a high quality spunbond web can be obtained with even or homogeneous structural properties. The invention is explained in greater detail below wit reference to a drawing that shows a single embodiment. Therein, schematically: FIG. 1 shows a vertical section through an apparatus according to the invention, FIG. 2 shows in enlarged scale detail A of FIG. 1, FIG. 3 shows a second embodiment of the structure according to FIG. 2, FIG. 4 shows a third embodiment of the structure according to FIG. 2, and FIG. 5 shows a fourth embodiment of the structure according to FIG. 2. The figures show an apparatus for the continuous manufacture of a spunbond web from aerodynamically stretched filaments made of a thermoplastic resin. The apparatus has a spinneret 1 for making the filaments. Downstream of the spinneret 1 is a cooling chamber 2 that is supplied with cool process air to cool the filaments. The cooling chamber 2 is here preferably subdivided into two cooling compartments 3 and 4, in which the filaments are cooled with process air at a different temperatures. According to a preferred embodiment of the invention, the temperature of the process air that is applied to the filaments in the upstream cooling compartment 3 is higher than the temperature of the process air that is applied to the filaments in the downstream cooling compartment 4. Downstream of the cooling chamber 2 is a stretching unit 5 that aerodynamically stretches the filaments. Preferably, as in the illustrated embodiment, the cooling chamber 2 is connected here via an intermediate passage 6 to the stretching unit 5. The connection region between the cooling chamber 2 and the stretching unit 5 is designed according to the invention so it is closed. This means that in this transition region and particularly in the region of the intermediate passage 6, substantially no air can enter the flow path of the filaments from outside. Advantageously, as in the illustrated embodiment, the intermediate passage 6 has a converging shape from the cooling chamber 2 to the stretching unit 5. In other words, the intermediate passage 6 narrows from the cooling chamber to the stretching unit 5. According to the invention, the stretching unit 5 has a stretching passage 7 whose walls 8 and 9 diverge over at least a part of the length of the stretching passage 7. The passage walls 8 and 9 thus form at least one diverging section 10 in which the spacing between the passage walls 8 and 9 increases downward. These passage walls 8 and 9 are the passage walls 8 and 9 of the stretching passage 7 that are transversely spaced relative to the machine or travel direction of the spunbond web. The travel direction of the spunbond web is indicated in FIG. 1 by a double arrow. In FIG. 1, it is apparent that downstream of the stretching unit 5 is a depositing unit 11 that consists preferably, as in the illustrated embodiment, of an upstream diffuser 12 and a downstream diffuser 13. Moreover, one can also see in FIG. 1 that an ambient air inlet slit 14 is provided between the upstream diffuser 12 and the downstream diffuser 13. Each diffuser 12 and 13 has an upper converging part as well as a lower diverging part. Accordingly, each diffuser 12 and 13 has a narrowest region between the upper converging part and the lower diverging part. It is advantageous for the diffuser walls in the diverging part of the upstream diffuser 12 and/or the downstream diffuser 13 to be adjustable, so that the apex angle of the respective diverging parts are adjustable. Under the depositing unit 11, a continuously moved foraminous deposition belt 15 is provided, as a depositing device for the spunbond web. Beneath this foraminous deposition belt 15, at least one suction apparatus C not shown in the figures C is provided advantageously, by means of which air can be drawn down through the foraminous deposition belt 15 in the usual way. FIGS. 2-5 show the third embodiments for the design of the stretching passage 7 of the stretching unit 5. In all these illustrated embodiments, additional air is blown into the stretching passage 7 at the upstream end of the diverging stretching passage section or at the upstream end of the diverging section 10 or shortly before the diverging section 10. The introduction of the air here takes place advantageously in the direction of travel of the filaments or of the filament bundle, and preferably tangentially to the filaments or to the filament bundle. As can be seen in FIGS. 2-5, the air injection takes place preferably from both facing passage walls 8 and 9 and, here, level with the stretching unit 5. Here, it falls within the scope of the invention that air is blown in with the condition that the filament bundle is made broader, where the opening angle of the filament bundle is preferably 0.1-1°. This broadening of the filament bundle is indicated in FIGS. 2-5. To the extent that here and below the expression upstream end of the diverging section 10 is used, it refers particularly to the upstream third, preferably to the upstream fourth, and most preferably to the upstream fifth of the diverging section 10, with respect to the length of the diverging section 10. FIG. 2 shows a first embodiment of the stretching unit 5 according to the invention, where the stretching passage 7 has passage walls 8 and 9 that diverge over its entire length. In other words, the entire stretching passage 7 is divergent. The air intake here is at the upstream end of the diverging stretching passage 7. The passage walls 8 and 9 are symmetrical to a middle plane M. In addition, the divergence angle between the passage walls 8 and 9 remains constant over the length of the stretching passage 7. In the illustrated embodiment according to FIG. 3, the stretching passage 7 has an upstream parallel section 16 with parallel passage walls 8 and 9, downstream of which is the diverging section 10. The air intake here is at the upstream end of this diverging section 10. It is apparent in FIG. 3 that the diverging section 10 is longer than the parallel section 16, namely approximately twice as long. In the embodiment according to.FIG. 3, the passage walls 8 and 9 in the diverging section 10 are also symmetrical to the middle plane M, and the divergence angle remains constant over the entire length of the diverging section 10. FIG. 4 shows an embodiment in which the stretching passage 7 has an upstream converging section 17 with converging passage walls 8 and 9, immediately downstream of which is the diverging section 10. The air intake here too is at the upstream end of the diverging section 10. The diverging section 10, in the illustrated embodiment according to FIG. 4, is longer than the converging section 17, namely approximately twice as long. FIG. 5 shows an embodiment of the stretching unit 5 in which the stretching unit 7 has an upstream converging section 17 with converging passage walls 8 and 9, downstream of which is a parallel section 16. Directly downstream of the parallel section 16 is the diverging section 10. The air feed here too is at the upstream end of the diverging section 10. The length of the diverging section 10, in the illustrated embodiment, is greater than the length of the remaining stretching passage 7 consisting of the converging section 17 and the parallel section 16. In the diverging section 10, the passage walls 8 and 9 are symmetrical to the middle plane M. The divergence angle remains constant over the length of the diverging section 10. Claims: 1. An apparatus for the manufacture of a spunbond web made of filaments wherein a spinneret for producing the filaments is provided, downstream of the spinneret is a cooling chamber (2) that is supplied with process air to cool the filaments, a stretching unit (5) for stretching the filaments is connected to the cooling chamber (2), and wherein a connection region between the cooling chamber (2) and the stretching unit (5) is closed, the stretching unit (5) has a stretching passage (7) whose passage walls (8 and 9) diverge over at least a part of the length of the stretching passage (7), and a depositing device for the deposition of the filaments for the spunbond web is provided. 2. The apparatus according to claim 1 wherein the cooling chamber (2) is subdivided into at least two cooling compartments (3 and 4), in which the filaments can be cooled with process air at different temperatures. 3. The apparatus according to one of claims 1 or 2 wherein, between the cooling chamber (2) and the stretching unit (5), an intermediate passage (6) is arranged that has a converging shape from the cooling chamber (2) to the stretching unit (5). 4. The apparatus according to one of claims 1-3 wherein, in the stretching unit (5), at the upstream end of the diverging stretching passage section (10) or shortly before the diverging stretching passage section (10), additional air is introduced into the stretching passage (7). 5. The apparatus according to one of claims 1-4 wherein the stretching passage (7) has diverging passage walls (8 and 9) over its entire length or substantially over its entire length. 6. The apparatus according to one of claims 1-4 wherein the stretching passage (7) has parallel passage walls (8 and 9) over a part of its length, and wherein downstream of these parallel passage walls (8 and 9) are diverging passage walls (8 and 9). 7. The apparatus according to one of claims 1-4 wherein the stretching passage has converging passage walls (8 and 9) over a part of its length, and wherein downstream of the converging passage walls (8 and 9) are diverging passage walls (8 and 9). 8. The apparatus according to one of claims 1-4 wherein the stretching passage (7) has over part of its length converging passage walls (8 and 9) downstream of which are parallel passage walls (8 and 9) downstream of which are diverging passage walls (8 and 9). 9. The apparatus according to one of claims 1-8 wherein downstream of a stretching unit (5) is a stretching unit (11) with at least one diffuser (12 and 13). 10. The apparatus according to claim 9 wherein the repositioning unit (11) consists of an upstream diffuser (12) and an adjacent downstream diffuser (13), and wherein an ambient air inlet slit (14) is provided between the upstream diffuser (12) and the downstream diffuser (13). 11. The apparatus according to one of claims 1-10 wherein the depositing device is a continuously moved foraminous deposition belt (15) for the spunbond web. An apparatus for the manufacture of a spunbond web from filaments wherein a spinneret for producing filaments is provided. Downstream of the spinneret is a cooling chamber into which the process air is fed to cool the filaments. A stretching unit for stretching the filaments is connected to the cooling chamber, and the connection region between the cooling chamber and the stretching unit is closed. This stretching unit has a stretching passage whose passage walls diverge over at least a part of the length of the stretching passage. A depositing device for the deposition of the filaments for the spunbond web is provided.

Full Text

Description:
The invention relates to an apparatus for the manufacture of a spunbond web
made of filaments. The filaments consist typically of a thermoplastic resin.
An apparatus of the above-mentioned type is known in different embodiments
that are used in practice. The filaments are spun first with the help of a
spinneret, and then are usually passed through a cooling chamber. After
cooling, the filaments or the filament bundle reach a stretching passage of a
stretching unit in which they are stretched aerodynamically. The transverse
width of the stretching passage in the machine or travel direction of the spinning
fleece is here normally 10-20 mm. Because of this relatively small dimension,
the filament bundle in the stretching unit is compacted relatively strongly. This
has the disadvantage, in many known installations, that the filaments can be
separated only with considerable difficulty and deposited as individual filaments.
The object of the invention is to provide an apparatus of the type mentioned
above by means of which the filament bundle produced can be separated in a
simple and effective manner into individual filaments that can then be deposited
for the spunbond web.
To attain this object, the invention proposes an apparatus for the continuous
manufacture of a spunbond web from filaments, wherein
a spinneret for producing the filaments is provided, downstream of the spinneret
is a cooling chamber that is supplied with process air to cool the filaments,
a stretching unit for stretching the filaments is connected to the cooling
chamber,

a connection region between the cooling chamber and the stretching unit is
closed,
the stretching unit has a stretching passage whose passage walls diverge over
at least a part of the length of the stretching passage, and
a depositing device for the deposition of the filaments for the spunbond web is
provided.
A spinneret is in particular a spinneret that spins the filaments. The spun
filaments are then fed through the cooling chamber in which the cooling of the
filaments takes place. It is within the scope of the invention that the cooling
chamber is a closed chamber that, in addition to the process air intake, and in
addition to the inlet opening and outlet opening for the filament band, is closed
or substantially closed. According to the invention, the connection region
between the cooling chamber and the stretching unit is closed. In the
connection region or the transition region between the cooling chamber and the
stretching unit there is thus, according to the invention, no air feed or
substantially no air feed into the system or into the flow path of the filaments.
In the context of the invention, a diverging design of the passage walls of the
stretching passage means in particular that the passage walls are
arranged/designed to diverge transversely to the machine direction or
transversely to the spunbond web. The spacing between these passage walls
increases in the diverging section in the direction toward the depositing device.
The length of the stretching passage moreover means the extent of the
stretching passage between the cooling chamber and the depositing device.
The diverging part of the stretching passage is also referred to below as the
diverging stretching passage section or in brief as the diverging section.

A greatly preferred embodiment of the invention is characterized in that the
cooling chamber is subdivided into at least two cooling compartments, in which
the filaments in each case can be cooled with process air at a different
temperature. This special embodiment has been found to be particularly
advantageous in the scope of the invention. According to an embodiment, the
temperature of the fed process air in the upstream upper cooling compartment
is higher than the temperature of the fed process air in the lower downstream
cooling compartment. The upstream upper cooling compartment here relates to
the cooling compartment into which the filaments enter first.
According to the invention, the connection region between the cooling chamber
and the stretching unit is closed. The stretching unit is thus connected to the
cooling chamber with the condition that no introduction of air or substantially no
introduction of air takes place in the connection region between the cooling
chamber and the stretching unit. The stretching unit can here be connected
directly to the cooling chamber without any air-feed slit. According to a third
embodiment of the invention, an intermediate passage is arranged between the
cooling chamber and the stretching unit. Here, the fact that no air is introduced
from the outside or substantially no air is introduced from the outside into this
intermediate passage falls within the scope of the invention. This means that
only the process air from the cooling chamber is introduced into the
intermediate passage and that otherwise no air introduction or substantially no
air introduction from the outside takes place. It is preferred for the intermediate
passage to have a converging shape from the cooling chamber to the stretching
unit.
Here, the intermediate passage walls, which are spaced transversely to the
machine direction or transversely to the travel direction of the spunbond web,
converge. The intermediate passage thus narrows from the cooling chamber to
the stretching unit. According to an embodiment of the invention, different

convergence angles of the intermediate passage can be used. The fact that the
lower end of the intermediate passage is connected to the stretching passage of
the stretching unit without an intake slit for air or substantially without an intake
slit for air falls within the scope of the invention. Thus, only the process air (with
the filament), and no additional air or substantially no additional air, reaches the
stretching passage from the intermediate passage.
However, it is recommended that in the stretching unit, at the upstream end of
the diverging stretching passage section or slightly upstream of the diverging
stretching passage section, additional air is injected into the stretching passage.
Here, the air is advantageously injected parallel to the travel direction of the
filaments or the filament bundle, and preferably tangentially to the filament
bundle. The air is blown in tangentially and preferably as a boundary layer. It is
recommended that the air injection be from opposite facing passage walls or
facing diverging passage walls of the stretching passage and, here, preferably
at the same height with respect to the length of the stretching passage. Such a
two-sided air feed can also take place twice or repeatedly at different heights of
the stretching passage. The air injection takes place advantageously with the
condition that the filament bundle is made broader in the machine direction or in
the travel direction of the spunbond web. In this process, it is preferred to
operate in such a way that the opening angle of the filament bundle is 0.1-10°,
preferably 0.1-1°.
The expression "at the upstream end of the diverging stretching passage
section" means in particular the upstream third, preferably the upstream fourth,
and particularly preferably the upstream fifth of the diverging stretching passage
section, with respect to the length of the diverging stretching passage section.
The spacing between the passage walls of the stretching passage is
advantageously 5-30 mm, preferably 8-25 mm, and preferably 10-20 mm.

It is within the scope of the invention that at least one fourth, preferably at least
one third of the length of the stretching passage diverges or is designed as a
diverging section. At least 40% of the length of the stretching passage is
preferably diverging or has a diverging flow cross section. According to a first
preferred embodiment of the invention, the stretching passage has diverging
passage walls over its entire length or substantially over its entire length.
According to this embodiment, the entire stretching passage or substantially the
entire stretching passage diverges. It falls within the scope of the invention for
the stretching passage to diverge over at least 90%, preferably over at least
95% of its length.
According to an additional preferred embodiment of the invention, the stretching
passage has over a part of its length parallel passage walls (parallel section)
and downstream of this part are diverging passage walls (diverging section).
Here, it falls within the scope of the invention that the stretching passage in this
embodiment consists exclusively of the mentioned parallel section and the
downstream diverging section. The additional air feed takes place in this
embodiment either at the end of the parallel section or at the upstream end of
the diverging section of the stretching passage. The end of the parallel passage
here refers in particular to the downstream third with respect to the length of the
parallel section, preferably the farthest downstream fourth, and most preferably
the farthest downstream fifth of the parallel section. The upstream end of the
diverging section here and below means in particular the farthest upstream third
with respect to the length of the diverging section, preferably the farthest
upstream fourth, and most preferably the farthest upstream fifth of the diverging
section. It is preferred for the diverging section of this embodiment to be longer
than the parallel section, the diverging section being advantageously at least
1.5 times the length of the parallel section.

According to a preferred embodiment of the invention, the stretching passage
has converging passage walls (converging section) over part of its length, which
are then ed by diverging passage walls (diverging section). Here, it falls within
the scope of the invention that the stretching passage in this embodiment
consists exclusively of the converging and the diverging section. Thus, the
diverging section is immediately downstream of the converging section. In this
embodiment, the additional air feed is advantageously in the transitional region
between the converging section and the diverging section, or at the upstream
end of the diverging section. It is advantageous in this embodiment for the
diverging section to be longer than the converging section, and the diverging
section is preferably 1.5 times the length of the converging section.
According to an additional embodiment of the invention, the stretching passage
has over a part of its length converging walls (converging section), downstream
of which are parallel passage walls (parallel section), and downstream of which
in turn are diverging passage walls (diverging section). According to an
embodiment, the stretching passage here consists exclusively of the converging
section, the next downstream parallel section, and in turn the next downstream
diverging section. However, in principle, the last-mentioned diverging section
can also be a downstream parallel section. In this embodiment, the additional
air feed takes place advantageously at the end of the (upstream) parallel
section or at the upstream end of the diverging section. The end of the parallel
section means the farthest downstream third, preferably the farthest
downstream fourth, and most preferably the farthest downstream fifth of the
parallel section, with respect to the length of the parallel section. In this
embodiment (converging-parallel-diverging), it is recommended for the
diverging section to be the longest passage section. This means that the
diverging section in each case is longer than the parallel section and longer
than the convergent section. According to a particularly recommended

embodiment, the diverging section is longer than the total passage section
consisting of the converging and parallel section.
According to a preferred embodiment of the invention, the diverging passage
walls of the diverging section are in an arrangement that is symmetric with
respect to a middle plane that runs vertically through the stretching passage. In
principle, the scope of the invention also includes that the diverging passage
walls can be arranged asymmetrically with respect to this middle plane. In that
case, one of the two diverging passage walls would thus have a stronger
inclination or slanted position than the other facing passage wall. According to a
preferred embodiment of the invention, the divergence angle of the diverging
section remains constant over the length of the diverging section. However, in
principle, it is also possible for the divergence angle to change over the length
of the diverging section.
it falls within the scope of the invention that the cooling chamber and the
stretching unit of the apparatus according to the invention form a closed unit.
Here, air feed into the aggregate consisting of the cooling chamber and the
stretching unit is limited at least substantially to the introduction of the process
air into the cooling chamber, on the one hand, and to the additional air fed in
upstream of the diverging section or at the upstream end of the diverging
section in the stretching passage, on the other hand. Naturally, air can also
reach the cooling chamber from above with the deposition belt.
A particular embodiment, which is particularly important within in the scope of
the invention, is characterized in that downstream of the stretching unit a
repositioning unit with at least one diffuser. Thus, the filaments are, or the
filament bundle is, led through at least one diffuser after the stretching unit. The
diffuser has at least regions with diverging diffuser walls. The diffuser walls are
here spaced transversely to the machine direction or transversely to the travel

direction of the spunbond web. According to a recommended embodiment, the
repositioning unit consists of an upstream diffuser and a next downstream
diffuser. It is advantageous to provide an ambient air inlet slit between the
upstream diffuser and the downstream diffuser. Because of the exit pulse from
the upstream diffuser, air is sucked out of the environment through this ambient
air inlet slit. The width of the ambient air inlet slit is advantageously adjustable.
It falls within the scope of the invention that the depositing device of the
apparatus according to the invention is a continuously moving foraminous
deposition belt for the spunbond web. At least one suction apparatus is
advantageously provided under the foraminous deposition belt, by means of
which air can be sucked through the foraminous deposition belt.
The invention is based on the discovery that qualitatively a very high quality
spunbond web can be manufactured with the apparatus according to the
invention, which is characterized particularly by a homogeneous structure and
homogeneous properties. The invention is based particularly on the discovery
that, as a result of the design of the stretching unit according to the invention,
an undesired compaction of the filament bundle can be avoided or any
compaction that has already occurred can be reduced greatly. The treatment
according to the invention of the filament bundle can result in an effective
spacing between the individual filaments. Thus, with the design according to
the invention, a high number of filaments can be deposited in the form of
individual filaments. As a result, the quality of the spunbond web manufactured
according to the invention can be increased considerably in comparison to a
spunbond web manufactured according to the prior art. Moreover, it should be
emphasized that the success according to the invention can be achieved using
relatively simple and cost effective measures. As a result, a high quality
spunbond web can be obtained with even or homogeneous structural
properties.

The invention is explained in greater detail below wit reference to a drawing that
shows a single embodiment. Therein, schematically:
FIG. 1 shows a vertical section through an apparatus according to the
invention,
FIG. 2 shows in enlarged scale detail A of FIG. 1,
FIG. 3 shows a second embodiment of the structure according to FIG. 2,
FIG. 4 shows a third embodiment of the structure according to FIG. 2,
and
FIG. 5 shows a fourth embodiment of the structure according to FIG. 2.
The figures show an apparatus for the continuous manufacture of a spunbond
web from aerodynamically stretched filaments made of a thermoplastic resin.
The apparatus has a spinneret 1 for making the filaments. Downstream of the
spinneret 1 is a cooling chamber 2 that is supplied with cool process air to cool
the filaments. The cooling chamber 2 is here preferably subdivided into two
cooling compartments 3 and 4, in which the filaments are cooled with process
air at a different temperatures. According to a preferred embodiment of the
invention, the temperature of the process air that is applied to the filaments in
the upstream cooling compartment 3 is higher than the temperature of the
process air that is applied to the filaments in the downstream cooling
compartment 4.
Downstream of the cooling chamber 2 is a stretching unit 5 that
aerodynamically stretches the filaments. Preferably, as in the illustrated

embodiment, the cooling chamber 2 is connected here via an intermediate
passage 6 to the stretching unit 5. The connection region between the cooling
chamber 2 and the stretching unit 5 is designed according to the invention so it
is closed. This means that in this transition region and particularly in the region
of the intermediate passage 6, substantially no air can enter the flow path of the
filaments from outside. Advantageously, as in the illustrated embodiment, the
intermediate passage 6 has a converging shape from the cooling chamber 2 to
the stretching unit 5. In other words, the intermediate passage 6 narrows from
the cooling chamber to the stretching unit 5.
According to the invention, the stretching unit 5 has a stretching passage 7
whose walls 8 and 9 diverge over at least a part of the length of the stretching
passage 7. The passage walls 8 and 9 thus form at least one diverging section
10 in which the spacing between the passage walls 8 and 9 increases
downward. These passage walls 8 and 9 are the passage walls 8 and 9 of the
stretching passage 7 that are transversely spaced relative to the machine or
travel direction of the spunbond web. The travel direction of the spunbond web
is indicated in FIG. 1 by a double arrow.
In FIG. 1, it is apparent that downstream of the stretching unit 5 is a depositing
unit 11 that consists preferably, as in the illustrated embodiment, of an
upstream diffuser 12 and a downstream diffuser 13. Moreover, one can also
see in FIG. 1 that an ambient air inlet slit 14 is provided between the upstream
diffuser 12 and the downstream diffuser 13. Each diffuser 12 and 13 has an
upper converging part as well as a lower diverging part. Accordingly, each
diffuser 12 and 13 has a narrowest region between the upper converging part
and the lower diverging part. It is advantageous for the diffuser walls in the
diverging part of the upstream diffuser 12 and/or the downstream diffuser 13 to
be adjustable, so that the apex angle of the respective diverging parts are
adjustable.

Under the depositing unit 11, a continuously moved foraminous deposition belt
15 is provided, as a depositing device for the spunbond web. Beneath this
foraminous deposition belt 15, at least one suction apparatus C not shown in
the figures C is provided advantageously, by means of which air can be drawn
down through the foraminous deposition belt 15 in the usual way.
FIGS. 2-5 show the third embodiments for the design of the stretching passage
7 of the stretching unit 5. In all these illustrated embodiments, additional air is
blown into the stretching passage 7 at the upstream end of the diverging
stretching passage section or at the upstream end of the diverging section 10 or
shortly before the diverging section 10. The introduction of the air here takes
place advantageously in the direction of travel of the filaments or of the filament
bundle, and preferably tangentially to the filaments or to the filament bundle. As
can be seen in FIGS. 2-5, the air injection takes place preferably from both
facing passage walls 8 and 9 and, here, level with the stretching unit 5. Here, it
falls within the scope of the invention that air is blown in with the condition that
the filament bundle is made broader, where the opening angle of the filament
bundle is preferably 0.1-1°. This broadening of the filament bundle is indicated
in FIGS. 2-5.
To the extent that here and below the expression upstream end of the diverging
section 10 is used, it refers particularly to the upstream third, preferably to the
upstream fourth, and most preferably to the upstream fifth of the diverging
section 10, with respect to the length of the diverging section 10.
FIG. 2 shows a first embodiment of the stretching unit 5 according to the
invention, where the stretching passage 7 has passage walls 8 and 9 that
diverge over its entire length. In other words, the entire stretching passage 7 is
divergent. The air intake here is at the upstream end of the diverging stretching

passage 7. The passage walls 8 and 9 are symmetrical to a middle plane M. In
addition, the divergence angle between the passage walls 8 and 9 remains
constant over the length of the stretching passage 7.
In the illustrated embodiment according to FIG. 3, the stretching passage 7 has
an upstream parallel section 16 with parallel passage walls 8 and 9,
downstream of which is the diverging section 10. The air intake here is at the
upstream end of this diverging section 10. It is apparent in FIG. 3 that the
diverging section 10 is longer than the parallel section 16, namely
approximately twice as long. In the embodiment according to.FIG. 3, the
passage walls 8 and 9 in the diverging section 10 are also symmetrical to the
middle plane M, and the divergence angle remains constant over the entire
length of the diverging section 10.
FIG. 4 shows an embodiment in which the stretching passage 7 has an
upstream converging section 17 with converging passage walls 8 and 9,
immediately downstream of which is the diverging section 10. The air intake
here too is at the upstream end of the diverging section 10. The diverging
section 10, in the illustrated embodiment according to FIG. 4, is longer than the
converging section 17, namely approximately twice as long.
FIG. 5 shows an embodiment of the stretching unit 5 in which the stretching unit
7 has an upstream converging section 17 with converging passage walls 8 and
9, downstream of which is a parallel section 16. Directly downstream of the
parallel section 16 is the diverging section 10. The air feed here too is at the
upstream end of the diverging section 10. The length of the diverging section
10, in the illustrated embodiment, is greater than the length of the remaining
stretching passage 7 consisting of the converging section 17 and the parallel
section 16. In the diverging section 10, the passage walls 8 and 9 are

symmetrical to the middle plane M. The divergence angle remains constant
over the length of the diverging section 10.

Claims:
1. An apparatus for the manufacture of a spunbond web made of filaments
wherein
a spinneret for producing the filaments is provided,
downstream of the spinneret is a cooling chamber (2) that is supplied with
process air to cool the filaments,
a stretching unit (5) for stretching the filaments is connected to the cooling
chamber (2), and wherein a connection region between the cooling chamber (2)
and the stretching unit (5) is closed,
the stretching unit (5) has a stretching passage (7) whose passage walls (8 and
9) diverge over at least a part of the length of the stretching passage (7), and
a depositing device for the deposition of the filaments for the spunbond web is
provided.
2. The apparatus according to claim 1 wherein the cooling chamber (2) is
subdivided into at least two cooling compartments (3 and 4), in which the
filaments can be cooled with process air at different temperatures.
3. The apparatus according to one of claims 1 or 2 wherein, between the
cooling chamber (2) and the stretching unit (5), an intermediate passage (6) is
arranged that has a converging shape from the cooling chamber (2) to the
stretching unit (5).

4. The apparatus according to one of claims 1-3 wherein, in the stretching unit
(5), at the upstream end of the diverging stretching passage section (10) or
shortly before the diverging stretching passage section (10), additional air is
introduced into the stretching passage (7).
5. The apparatus according to one of claims 1-4 wherein the stretching
passage (7) has diverging passage walls (8 and 9) over its entire length or
substantially over its entire length.
6. The apparatus according to one of claims 1-4 wherein the stretching
passage (7) has parallel passage walls (8 and 9) over a part of its length, and
wherein downstream of these parallel passage walls (8 and 9) are diverging
passage walls (8 and 9).
7. The apparatus according to one of claims 1-4 wherein the stretching
passage has converging passage walls (8 and 9) over a part of its length, and
wherein downstream of the converging passage walls (8 and 9) are diverging
passage walls (8 and 9).
8. The apparatus according to one of claims 1-4 wherein the stretching
passage (7) has over part of its length converging passage walls (8 and 9)
downstream of which are parallel passage walls (8 and 9) downstream of which
are diverging passage walls (8 and 9).
9. The apparatus according to one of claims 1-8 wherein downstream of a
stretching unit (5) is a stretching unit (11) with at least one diffuser (12 and 13).
10. The apparatus according to claim 9 wherein the repositioning unit (11)
consists of an upstream diffuser (12) and an adjacent downstream diffuser (13),
and wherein an ambient air inlet slit (14) is provided between the upstream
diffuser (12) and the downstream diffuser (13).

11. The apparatus according to one of claims 1-10 wherein the depositing
device is a continuously moved foraminous deposition belt (15) for the
spunbond web.

An apparatus for the manufacture of a spunbond web from filaments wherein a spinneret for producing filaments is provided. Downstream of the spinneret is a cooling chamber into which the process air is fed to cool the filaments. A
stretching unit for stretching the filaments is connected to the cooling chamber, and the connection region between the cooling chamber and the stretching unit is closed. This stretching unit has a stretching passage whose passage walls diverge over at least a part of the length of the stretching passage. A depositing device for the deposition of the filaments for the spunbond web is provided.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=xVEoM9RTkF3AfrpqrY7PiQ==&loc=wDBSZCsAt7zoiVrqcFJsRw==

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Patent Number

268725

Indian Patent Application Number

1012/KOL/2008

PG Journal Number

38/2015

Publication Date

18-Sep-2015

Grant Date

14-Sep-2015

Date of Filing

10-Jun-2008

Name of Patentee

REIFENHAUSER GMBH & CO. KG. MASCHINENFABRIK

Applicant Address

SPICHER STRASSE 46-48, 53839 TROISDORF

Inventors:

#	Inventor's Name	Inventor's Address
1	HANS-GEORG GEUS	BAHNHOFSTR. 54A 53859 NIEDERKASSEL
2	DETLER FREY	SCHLEHENWEG 5, 53859 NIEDERKASSEL

PCT International Classification Number

B32B5/02; B29C43/46

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	07 012 793.1	2007-06-29	EUROPEAN UNION