ES2972095T3 - Hydroentangled filter material for smoking articles with improved extension behavior - Google Patents

Description

DESCRIPTION

Hydroentangled filter material for smoking articles with improved extension behavior

field of invention

The invention relates to a filter material suitable for the production of a segment in a smoking article, which has a favorable plastic extension behavior in the transverse direction, so that segments for smoking articles can be produced from it. efficient manner. The invention also relates to a segment for a smoking article produced from this filter material.

Background and state of the art

Smoking articles are typically rod-shaped articles that consist of at least two rod-shaped segments arranged one after the other. One segment contains a material that when heated can form an aerosol and at least one other segment serves to influence the properties of the aerosol.

In the case of the smoking article, it may be a cigarette with a filter, in which a first segment contains the aerosol-forming material, in particular tobacco, and in which another segment is configured as a filter and serves to filter the aerosol. The aerosol is generated in this case by burning the aerosol-forming material and the filter serves mainly to filter the aerosol and provide the filter cigarette with a defined tensile strength.

However, the smoking article may also be a so-called tobacco heater, in which the aerosol-forming material is only heated but not burned. Due to this, the number and quantity of substances harmful to health in the aerosol are reduced. A smoking article of this type is also made up of at least two, however more often more, in particular four segments. One segment contains the aerosol-forming material, which typically comprises tobacco, reconstituted tobacco, or tobacco prepared by other processes. Furthermore, the partially optional segments in the smoking article serve to subsequently conduct the aerosol, cool the aerosol or filter the aerosol.

The segments are in most cases wrapped by a wrapping material. Paper is very frequently used as a wrapping material.

In the following, unless explicitly stated or the contrary appears directly from the context, "segment" means the segment of a smoking article that does not contain the aerosol-forming material, but serves, for example, to subsequently conduct, cool or filter the aerosol.

From the state of the art it is known to form segments of this type from polymers such as cellulose acetate or polylactides. After consumption of the smoking article, the smoking article must be disposed of appropriately. However, in many cases the consumer simply throws the consumed smoking article into the environment and attempts to restrict this behavior through information or fines have had little success.

Since cellulose acetate and polylactides biodegrade very slowly in the environment, the industry is interested in manufacturing smoking article segments from other materials that are more biodegradable. Furthermore, in the European Union, for example, regulations are being discussed that significantly reduce or prohibit the use of unnatural polymers in smoking articles, so there is also interest in having alternative segments for smoking articles.

It is known in the state of the art to produce segments for smoking articles, in particular filter segments, from paper. Although segments of this type can generally biodegrade well, they also have disadvantages. For example, paper filter segments generally have a high filtration efficiency and therefore lead to a dry aerosol, which affects the taste of the aerosol compared to cigarettes with usual cellulose acetate filter segments. Additionally, they often have a lower filtration efficiency for phenols than cellulose acetate.

One of the main reasons why filter segments made of paper have not yet found widespread use is their visual appearance. The cut surface of the mouth-end segment is usually visible at the mouth end of the smoking article, and the consumer is accustomed to a white, homogeneous surface of the usual cellulose acetate segments, in which they can hardly individual cut fibers can be distinguished. Paper segments, on the other hand, have a rough structure, apparently giving the consumer the impression of inferior quality. Therefore, paper segments are often only used as a sub-segment in a filter that is made up of several segments, so that the consumer cannot see the cut surface. The segment placed at the end of the mouth often additionally consists of cellulose acetate. Due to these optical deficiencies, the biodegradability benefits of a paper segment cannot be fully realized.

It is also known in the state of the art to produce segments for smoking articles from felt materials. In EP 2515689, for example, a filter material made of felt material has been described, which however predominantly contains fibers of polyvinyl alcohol, polylactides or other non-natural polymers and therefore cannot perform well. biodegradability requirements. Furthermore, the felt materials described therein are too thin to produce a visually attractive appearance on the cut surface of the segment manufactured therefrom.

The production of filter material for smoking articles from paper of easily biodegradable fibers is also known in the state of the art. A filter material of this type has been described in document US 2015/0374030, which, however, consists in a considerable proportion of cellulose pulp fibers from hemp, linen, abaca, sisal or cotton. These fibers are expensive and have strong fluctuations in quality due to their short growth period, compared to wood cellulose fibers. However, according to the teachings of US 2015/0374030, they are necessary to achieve at the same time a sufficiently porous structure and sufficiently high strength. The use of wood pulp is discouraged because it creates a dense and compact paper structure. In fact, the proportion of wood cellulose pulp should always be less than 50% by weight and in the industrially implemented embodiments this amount is less than 5% by weight. Due to the manufacturing process used for this purpose, the visual appearance of such filters is not attractive enough for the consumer.

Contrary to the teachings of the state of the art, the inventors of the present application have discovered that a filter material with a high proportion of wood pulp fibers can be produced in the form of a hydroentangled felt material, without the structure of the felt material becomes too dense or too compact. A corresponding filter material, which can be considered as a starting point for the present invention, is described in the unpublished international application PCT/EP2019/085125. This previously unpublished application has also described folding or crimping the filter material to form therefrom an endless strand of pleated or crimped filter material, which is subsequently wrapped with wrapping paper and cut into individual rods of length defined to form the aforementioned segments.

For example, when producing a segment, it is possible to first crimp a cellulose-based felt web in the longitudinal direction before shaping it into an endless strand and wrapping it with a wrapping material. Finally, the endless strand can be cut into suitable pieces for further processing.

When crimping the web, the web can be passed through two patterned rollers, which stamp this pattern onto the web. For example, this pattern may be a line pattern oriented in the machine direction of the web. Such embossed lines stretch and deform the web in the direction orthogonal to the machine direction, the transverse direction, so that an endless strand can then be more easily formed by pressing the web together in the transverse direction.

However, with the type of crimping described, it may occur that the band breaks in the transverse direction. Therefore, there is a need for a filter material that does not have this disadvantage or only to a lesser extent, but is otherwise as identical as possible to the preferred filter materials, in particular those described in the unpublished application. previously PCT/EP2019/085125 mentioned above.

EP3385425A1 describes a felt material of cellulose fibers, which is produced directly from a Lyocell spinning solution. The material comprises a network of essentially endless fibers, wherein the material has an oil absorption capacity of at least 1900 mass percent. Furthermore, a method and a device for producing such a material, a product or a composite material containing such a material and various possible uses for said material are described.

Document DE 12 95 453 B discloses a filter for tobacco products made of a wrapped fiber strand produced by gathering a fiber felt, wherein the fiber felt has, in a manner known per se, a proportion of deformed fibers. transversely to the direction of travel, where however this proportion of transversely deformed fibers has a size such that the fiber strand not yet wrapped has a volume per unit length that is at least 2:1 greater than a fiber strand produced in the same way from a felt of fibers of the same weight without transversely deformed fibers.

Document EP2228209A1 discloses an elastic laminate, in particular for elastic diaper closure elements, with outer layers of nonwoven material and an elastic sheet laminated at least in areas between the outer layers. At least one of the two outer layers consists of a felt material that can extend in a transverse direction, intertwined by water jets. The hydroentangled felt material has been pre-stretched in at least one axial direction in the region of the elastic sheet.

Summary of the invention

The invention is based on the object of providing a web-shaped filter material for a smoking article which can be processed with high productivity to give a segment of a smoking article and which is otherwise as similar as possible in regarding their properties to the preferred filter materials.

This object is solved by a hydroentangled felt according to claim 1, a segment for a smoking article according to claim 6, and a smoking article according to claim 10, as well as by a process for the production of a segment according to claim 9 and a method for producing the hydroentangled felt according to the invention according to claim 11. Advantageous developments are defined in the dependent claims.

The inventors have discovered that this object can be achieved by a filter material for the production of a segment for a smoking article, wherein the filter material is a web-shaped hydroentangled felt. Although the term "hydroentangled" initially indicates the underlying production process, it should be noted that a hydroentangled felt has characteristic structural properties that distinguish it from other felts and that, to the best of the inventors' knowledge, cannot be achieved identically by another production procedure. Unlike, for example, paper, where the strength is mainly due to hydrogen bonds and the fibers are arranged mainly in the plane of the paper, the strength in the case of hydroentangled felt is achieved by the interlacing of the fibers . A hydroentangled felt has a particularly porous structure, which makes it particularly well suited as a filter material for segments of smoking articles.

According to the invention, the hydroentangled felt contains at least 50% and at most 100% cellulose fibers, in each case with respect to the mass of the hydroentangled felt, wherein the hydroentangled fleece has a grammage of at least 15 g/m2 and a maximum of 60 g/m2. In this regard, the hydroentangled felt has a machine direction and a transverse direction that lie orthogonally to it in the plane of the web of the hydroentangled felt. Furthermore, the hydroentangled felt has a characteristic plastic deformability in the transverse direction, which is characterized in that, in a tensile test in the transverse direction according to ISO 1924-2:2008, the non-linear component of the energy of Strain absorbed by the hydroentangled felt up to half the elongation at break is at least 10% and at most 50% of the total strain energy absorbed by the hydroentangled felt up to half the elongation at break. This characteristic plastic deformability is more pronounced than in the case of conventional filter materials.

During the production and subsequent processing of hydroentangled felt, the hydroentangled felt runs through the machine in one direction, the so-called machine direction, and the hydroentangled felt has a direction orthogonal to the machine direction, which is in the plane of the hydroentangled felt band, transverse direction.

During processing of a filter material to form a segment of a smoking article, the hydroentangled felt is preferably crimped. To do this, the hydroentangled felt is passed, for example, through two rollers provided with a pattern, which stamp this pattern onto the web. Preferably, this pattern is a line pattern oriented in the machine direction of the web. The patterned lines stretch and deform the hydroentangled felt in the direction orthogonal to the machine direction, the transverse direction. A filter material deformed in this way can be pressed together more easily in the transverse direction and an endless thread can thus be generated for the production of the segments.

A problem with this method, however, is that a large extension in the transverse direction must be exerted on the web by the two rollers to cause a desired deformation of the hydroentangled felt and, therefore, there is a risk that the hydroentangled felt breaks in a transverse direction. One skilled in the art may now be tempted to increase the elongation at break of the hydroentangled felt in the transverse direction, so that the hydroentangled felt tolerates larger deformations without tearing. However, the inventors have recognized that this does not solve the problem, since to achieve permanent deformation in the transverse direction, then the elongation must be increased further, so that the risk of exceeding the breaking load in the transverse direction increases. even more.

According to the discoveries of the inventors, it is rather important that in the case of elongation in the transverse direction, to which the hydroentangled felt is exposed during crimping, a plastic and non-elastic permanent deformation occurs. If such plastic deformation can be achieved with a greater distance between the rollers during crimping, the risk of the hydroentangled felt tearing in the transverse direction during processing is reduced. In general, it should be sufficient in this regard to elongate the hydroentangled felt in the transverse direction to approximately half its elongation at break.

The inventors have now discovered that the hydroentangled felt can be provided by suitable methods with a structure that allows good plastic deformability in the transverse direction and thereby simplifies crimping. Appropriate procedures for this are explained below.

This plastic deformability in the transverse direction can be characterized in this regard by a tensile test according to ISO 1924-2:2008. In this tensile test, a strip 15 mm wide in the transverse direction is taken from the sample and elongated at a speed of 20 mm/min until failure. In this connection, the elongation £ and the applied force F are recorded, so that a force-elongation curve F(e) results. The elongation at break £b and the tensile strength F(£b) are also recorded. Up to half of the elongation at break £b/2 the deformation energy E absorbed by the hydroentangled felt results from

where in practice, the integral is calculated numerically.

This deformation energy is made up of an elastic proportion and a plastic proportion. The elastic deformation decreases after unloading, so it does not contribute to the curling result. Plastic deformation, on the other hand, is irreversible, so that a good result in curling can be expected even with low elongation using the two rollers, if the ratio of the plastic deformation energy to the total deformation energy is greater than with comparable state-of-the-art filter materials.

Elastic deformation is generally associated with a proportionality between elongation and force. Under the fictitious assumption that the hydroentangled felt behaves ideally in a linearly elastic manner up to half the elongation at break, the strain energy Elin up to half the elongation at break is calculated by

1£h £h1£h

E Un = -2H j ) j = -4Hj)c<,

The nonlinear component E<nl>that goes beyond this strain energy of the strain energy introduced into the hydroentangled felt to half the elongation at break is then

According to the inventors' findings, very good results in crimping can be achieved if the non-linear component of the strain energy absorbed up to half of the elongation at break in the transverse direction is at least 10% of the total strain energy. absorbed up to half of the elongation at break in the transverse direction, that is, it is applied

These considerations for quantifying plastic behavior can be illustrated by the diagram represented in Figure 1, as may occur, for example, when carrying out a tensile test in accordance with the ISO 1924-2:2008 standard. The elongation £ is represented on the x-axis 10, while the force F(£) required to generate this elongation is represented on the y-axis 11. Starting from a stress-free state 12, the elongation £ rises with a speed of 20 mm/min and at the same time the force F(£) is measured, where the force-deformation curve 13 is produced. The elongation increases in this respect until the sample tears in state 14, and from this determine the elongation at break £<b>and the tensile strength F(£<b>).

In the production of a segment from the hydroentangled felt, pieces of the hydroentangled felt may be subjected to stress, for example, up to approximately half the elongation at break £b/2, point 15, with the corresponding force F(£b/ 2), so that state 16 is achieved.

Line 17 connecting points 12 and 16 would represent a fictitious linear elastic behavior and the linear strain energy Elin corresponds to the area of the triangle formed by points 12,16 and 15. The total strain energy E, on the other hand, corresponds to the area delimited by the lines from point 12 to point 15, from point 15 to point 16 and line 13 from point 16 to point 12. The nonlinear component Enl of the strain energy, which is used in the framework of The invention for the characterization of the hydroentangled hair according to the invention, corresponds to that area that is delimited by lines 17 and 13, in each case between points 12 and 16. The more the force-deformation curve is bent upwards and The more it deviates from a fictitious linear elastic behavior, the greater the potential for plastic and therefore irreversible deformation.

In the production of segments from the hydroentangled felt according to the invention, the elongation in the transverse direction during crimping may, of course, differ from half the elongation at break, however the non-linear component of the strain energy up to Half the elongation at break has proven to be a suitable parameter regardless of the elongation actually applied and the actual elastic-plastic behavior to characterize the structure of the hydroentangled felt according to the invention and to predict the behavior of the hydroentangled felt during crimping.

For comparison, Figure 2 shows the behavior of a typical conventional filter material and not according to the invention. Also in this case, a tensile test is carried out in accordance with ISO 1924-2:2008 on a sample in the transverse direction. The elongation £ is represented on the x-axis 20, while the force F(e) required to generate this elongation is represented on the y-axis 21. Starting from a stress-free state 22, the elongation £ rises with a speed of 20 mm/min and at the same time the force F(£) is measured, where the force-deformation curve 23 is produced. The elongation increases in this respect until the sample tears in state 24, and from this determine the elongation at break £<b>and the tensile strength F(£<b>).

In the production of a segment from the hydroentangled felt, the hydroentangled felt may be stressed, for example, up to approximately half the elongation at break £<b>/2, point 25, with the corresponding force F(£<b >/2), so that state 26 is achieved.

Line 27 connecting points 22 and 26 would represent linear elastic behavior and the corresponding strain energy E<lin>corresponds to the area of the triangle formed by points 22, 26 and 25. The total strain energy E, on the other hand , corresponds to the area delimited by the lines from point 22 to point 25, from point 25 to point 26 and line 23 from point 26 to point 22. The nonlinear component E<nl>of the strain energy corresponds to that area that is delimited by lines 27 and 23, in each case between points 22 and 26. It can be seen that with a very similar elongation at break and a very similar linear proportion of the strain energy, the proportion of the strain energy does not linear is essentially smaller. Therefore, such a hydroentangled felt will react to deformation mainly elastically and, upon release of stresses, will recover essentially all of the deformation. To introduce a plastic deformation energy similar to that of the hydroentangled felt shown in Figure 1, indicated by line 28, the hydroentangled felt would have to be elongated up to point 29. The elongation necessary for this is clearly greater and, above all, the necessary force approximates the breaking stress in the transverse direction. In case of minor machine alterations or fluctuations in the quality of the hydroentangled felt, the hydroentangled felt can therefore tear in the transverse direction. On the contrary, the hydroentangled felt according to the invention of Figure 1 has a structure that allows permanent deformation in the transverse direction already with a reduced elongation, so that segments for articles for smoke.

The hydroentangled felt according to the invention contains cellulose fibers. According to the inventors' findings, cellulose fibers are necessary to provide the hydroentangled felt with sufficient strength so that it can be processed into a segment. According to the invention, the proportion of cellulose fibers in the hydroentangled felt is at least 50% and at most 100% of the mass of the hydroentangled felt, however preferably at least 60% and at most 100% and particularly preferably at least 70% and at most 95%, in each case based on the mass of the hydroentangled felt.

The cellulose fibers may be cellulose pulp fibers or regenerated cellulose fibers or mixtures thereof.

Cellulose pulp fibers are preferably obtained from coniferous wood, wood from broad-leaved trees or other plants, such as hemp, flax, jute, ramie, kenaf, kapok, coconut, abaca, sisal, bamboo, cotton or esparto grass. Blends of cellulose pulp fibers of different origin can also be used for the production of the hydroentangled felt. The cellulose pulp fibers are particularly preferably obtained from coniferous woods, because even a small proportion of such fibers gives the hydroentangled felt good strength.

The hydroentangled felt according to the invention may contain regenerated cellulose fibers. Preferably, the proportion of regenerated cellulose fibers is at least 5% and at most 50%, particularly preferably at least 10% and at most 45% and very particularly preferably at least 15% and as maximum of 40%, in each case with respect to the mass of the hydroentangled felt.

The regenerated cellulose fibers are preferably formed at least partially, in particular more than 70%, of viscose fibers, modal fibers, Lyocell® fibers, Tencel® fibers or mixtures thereof. These fibers have good biodegradability and can be used to optimize the strength of the hydroentangled felt and to adapt the filtration efficiency of the segment for the smoking article manufactured therefrom. Due to their production process, they are less variable than cellulose pulp fibers obtained from natural sources and help ensure that the properties of a segment made from the hydroentangled felt vary less than if exclusively cellulose pulp fibers were used. However, their production is more complex and they are usually more expensive than cellulose pulp fibers.

The grammage of the hydroentangled felt according to the invention is at least 15 g/m2 and at most 60 g/m2, preferably at least 18 g/m2 and at most 55 g/m2 and particularly preferably at least 20 g/m2 and a maximum of 50 g/m2. Weight influences the tensile strength of hydroentangled felt, with higher weight generally leading to higher strength. However, the grammage should not be too high because then the hydroentangled felt can no longer be processed at high speed into segments for smoking articles. The indications refer to a grammage measured according to the ISO 536:2019 standard.

In the case of the hydroentangled felt according to the invention, in a tensile test in transverse direction according to ISO 1924-2:2008, the non-linear component of the strain energy absorbed by the hydroentangled felt up to half of the elongation at break is at least 10% and at most 50% of the total strain energy absorbed by the hydroentangled felt up to half of the elongation at break. Preferably, the non-linear component of the strain energy absorbed by the hydroentangled felt up to half the elongation at break is at least 15% and at most 40% of the total strain energy absorbed by the hydroentangled felt up to half the elongation at break, and especially preferably the non-linear portion is at least 15% and at most 35%, and in particular at least 18% and at most 32%. In the preferred and especially preferred ranges a very good curling result can be achieved with moderate elongation and the risk of the hydroentangled felt tearing in the transverse direction is especially low.

The hydroentangled felt according to the invention may contain additives, such as alkyl ketene dimers (AKD), acid anhydrides, such as alkenyl succinic anhydrides (ASA), polyvinyl alcohol, waxes, fatty acids, starch, starch derivatives, carboxymethyl cellulose, alginates, chitosan, wet strength agents or substances for adjusting the pH value, such as for example organic or inorganic acids or bases to adjust specific properties. The hydroentangled felt according to the invention may alternatively or additionally also contain one or more additives selected from the group consisting of citrates, such as trisodium citrate or tripotassium citrate, malates, tartrates, acetates, such as sodium acetate or potassium acetate, nitrates, succinates, fumarates, gluconates, glycolates, lactates, oxalates, salicylates, a-hydroxycaprylates, phosphates, polyphosphates, chlorides and bicarbonates, and mixtures thereof.

The person skilled in the art is able to determine the type and quantity of said additives from his experience.

The hydroentangled felt according to the invention may also comprise still other substances that better adapt the filtration efficiency of the hydroentangled felt to that of cellulose acetate. In a preferred embodiment, the hydroentangled felt according to the invention comprises a substance selected from the group consisting of triacetin, propylene glycol, sorbitol, glycerol, polyethylene glycol, polypropylene glycol, polyvinyl alcohol and triethyl citrate or mixtures thereof. themselves.

In a preferred embodiment of the hydroentangled felt, at least a part of the cellulose fibers is filled with a filler material, wherein the filler material is particularly preferably formed by mineral particles and in particular carbonate particles. calcium. Since the hydroentangled felt structure is very porous, it is not suitable for containing filler materials, so it is favorable to load the cellulose fibers with the filler materials and thus fix them in the hydroentangled felt structure. Filler materials can serve to impart special properties to the hydroentangled felt.

The thickness of a layer of the hydroentangled felt, measured according to ISO 534:2011, is preferably at least 25 pm and at most 1000 pm, preferably at least 30 pm and at most 800 pm and particularly preferably at less than 35 pm and a maximum of 600 pm. The thickness influences the amount of hydroentangled felt that can be packed into the segment of the smoking article and therefore the tensile strength and filtration efficiency of the segment, however also the processability of the hydroentangled felt, in particularly when curled or folded for the production of a segment for a smoking article. Too great a thickness is unfavorable for such process steps, and thicknesses in the preferred and especially preferred ranges allow especially good processability of the hydroentangled felt according to the invention to give a segment of a smoking article.

The mechanical properties of the hydroentangled felt are important for processing the hydroentangled felt according to the invention to give a segment of a smoking article. The tensile strength with respect to the width of the hydroentangled felt in the transverse direction, measured according to ISO 1924-2:2008, is preferably at least 0.05 kN/m and at most 5 kN/m, so especially preferably at least 0.07 kN/m and at most 4 kN/m.

The elongation at break of the hydroentangled felt in the transverse direction, measured according to ISO 1924-2:2008, is therefore preferably at least 0.5% and at most 50% and particularly preferably at least 0. 8% and a maximum of 40%. The elongation at break is determined mainly by the length of the fibers, where longer fibers lead to a greater elongation at break and, therefore, this can be adapted within a wide range to the specific requirements of the hydroentangled felt.

The segments according to the invention for smoking articles can be produced from the hydroentangled felt according to the invention according to methods known per se from the state of the art. These processes comprise, for example, crimping the hydroentangled felt, forming an endless strand from the crimped hydroentangled felt, wrapping the endless strand by a wrapping material, and cutting the wrapped strand into individual rods of defined length. . In many cases, the length of such a rod amounts to an integer multiple of the length of the segment, which is to be used in the smoking article according to the invention and therefore the rods are cut into segments of the desired length. before or during the production of the smoking article.

The segment according to the invention for smoking articles comprises the hydroentangled felt according to the invention and a wrapping material.

Specifically, the segment comprises a hydroentangled felt pressed together in a transverse direction and a wrapping material, wherein the hydroentangled felt contains at least 50% and at most 100% cellulose fibers, in each case with respect to the mass. of hydroentangled felt. In this regard, the hydroentangled felt has a grammage of at least 15 g/m2 and a maximum of 60 g/m2. To determine the weight, the surface of the hydroentangled felt is taken as a basis when it is spread (that is, when it is no longer joined together). The hydroentangled felt has a transverse direction, in which the hydroentangled felt has been pressed together in the transverse direction. To make it easier to press together the hydroentangled felt in a transverse direction, it can be pre-shaped by curling or folding. The term "pressing together in transverse direction" should be understood in this sense broadly, and the verb "push" contained herein is not intended to suggest a specific mechanical way in which the state of "pressing together in transverse direction" is achieved. ". A "pleated" state, for example, is also a "cross-direction snap-together" state within the meaning of the present disclosure, regardless of the mechanical way in which the cross-direction pleating or shortening occurs. Furthermore, the hydroentangled felt in the non-pressure-bonded state in the transverse direction exhibits a characteristic plastic deformability in the transverse direction, which is characterized in that, in a tensile test in the transverse direction according to ISO 1924-2: 2008, the non-linear component of the strain energy absorbed by the hydroentangled felt up to half the elongation at break is at least 10% and at most 50% of the total strain energy absorbed by the hydroentangled felt up to the middle elongation. break elongation.

In a preferred embodiment of the segment according to the invention, the segment is cylindrical with a diameter of at least 3 mm and at most 10 mm, especially preferably at least 4 mm and at most 9 mm and very preferably especially preferably at least 5 mm and at most 8 mm. These diameters are favorable for the use of the segments according to the invention in smoking articles.

In a preferred embodiment of the segment according to the invention, the segment has a length of at least 4 mm and at most 40 mm, particularly preferably at least 6 mm and at most 35 mm and very particularly preferably of at least 10 mm and a maximum of 28 mm.

The tensile strength of the segment determines, among other things, what pressure difference the consumer must apply when using the smoking article to generate a certain volumetric flow through the smoking article and therefore has a significant influence on consumer acceptance of the smoking article. The tensile strength of the segment can be measured according to ISO 6565:2015 and is indicated in mm of water column (mmWG). To a very good approximation, the tensile strength of the segment is proportional to the length of the segment, so the tensile strength can also be measured on rods that differ from the segment only in length. From this, the tensile strength of the segment can be easily calculated.

The tensile strength of the segment per segment length is preferably at least 1 mmWG/mm and at most 12 mmWG/mm and particularly preferably at least 2 mmWG/mm and at most 10 mmWG/mm.

The wrapping material of the segment according to the invention is preferably a paper or a film.

The segment wrapping material according to the invention preferably has a grammage according to ISO 536:2019 of at least 20 g/m2 and at most 150 g/m2, particularly preferably at least 30 g/m2. and a maximum of 130 g/m2. A wrapping material with this preferred or especially preferred grammage gives the segment according to the invention, wrapped therewith, a particularly advantageous hardness.

Smoking articles according to the invention can be produced from the segment according to the invention according to methods known in the state of the art.

The smoking article according to the invention comprises a segment containing an aerosol-forming material and a segment comprising the hydroentangled felt according to the invention and a wrapping material.

Since the cutting surface of the segment according to the invention is visually very similar to that of a cellulose acetate segment, in a preferred embodiment, the segment of the smoking article located closest to the end of the mouth is a segment according to the invention.

In a preferred embodiment, the smoking article is a filtered cigarette and the aerosol-forming material comprises tobacco.

In a preferred embodiment, the smoking article is a smoking article, in the intended use of which the aerosol-forming material is only heated but not burned, and the aerosol-forming material preferably comprises a material selected from group consisting of tobacco, reconstituted tobacco, nicotine, glycerol, propylene glycol or mixtures thereof. In this regard, the aerosol-forming material may also be present in liquid form and is located in a suitable container in the smoking article.

According to the inventors' findings, the inventive nonlinear component of the strain energy can be achieved by aligning the fibers in the hydroentangled felt more strongly in the machine direction of the hydroentangled felt. This can be achieved by the methods according to the invention described below.

The hydroentangled felt according to the invention can be produced according to a process comprising the following steps A1 to A3.

A1 - provide a web of fibers comprising cellulose fibers, which has a machine direction and a transverse direction orthogonal to it which is in the plane of the web,

A2 - hydroentangle the fiber web by directing water jets on the fiber web to produce a hydroentangled fiber web,

A3 - dry the hydroentangled fiber web,

wherein in step A1 the proportion of cellulose fibers in the fiber web is selected such that the hydroentangled felt contains after drying in step A3 at least 50% and at most 100% cellulose fibers, with respect to the mass of the hydroentangled felt, and

wherein steps A1 and A2 are carried out so that the hydroentangled felt is given a characteristic plastic deformability in the transverse direction, which is characterized in that, in a tensile test in transverse direction according to the ISO 1924-2 standard :2008 performed on the hydroentangled felt after drying in step A3, the non-linear component of the strain energy absorbed by the hydroentangled felt up to half of the elongation at break is at least 10% and at most 50% of the total deformation energy absorbed by the hydroentangled felt up to half of the elongation at break, and where the hydroentangled felt after drying in stage A3 has a weight of at least 15 g/m2 and at most 60 g/m2.

In this regard, steps A1 and A2 can be carried out so that the cellulose fibers in the finished hydroentangled felt are tendentially oriented more in the machine direction than in the transverse direction.

The water jets directed in stage A2 on the fiber web cause the cellulose fibers to swirl, where the structure that favors favorable plastic behavior in the transverse direction can be created. By "water jet pressure" the person skilled in the art understands in this regard the pressure that is used to generate the water jet, for example in a pressure chamber. According to the inventors' findings, to achieve favorable plastic behavior of the hydroentangled felt, it is important that the proportion of fibers oriented in the transverse direction in the hydroentangled felt is small and that the fibers are oriented more in the machine direction and thickness direction. To generate this structure according to the invention in the hydroentangled felt, the water jets should be arranged close to each other in the transverse direction. Due to the proximity of the water jets hitting the fiber web at the same time, the water is deflected rather in the machine direction and not in the transverse direction and orients the fibers correspondingly in this direction.

The pressure of the water jets can be reduced in this respect compared to the pressure usually used. The distance and pressure of the water jets also depend largely on the size of the openings through which the water jets exit and, above all, also on the speed of the fiber web, so that the expert can select the concrete value through experience, according to concrete examples of implementation and through simple experiments.

In a preferred embodiment of the method according to the invention, a plurality of water jets are used to perform hydroentanglement in step A2, wherein the water jets are arranged in at least one row transversely to the machine direction. of the fiber band.

In a preferred embodiment of the method according to the invention, the hydroentanglement in step A2 is carried out by at least two rows of water jets directed on the fiber web, where particularly preferably at least one row of jets of water acts on each of the two sides of the fiber band.

In a preferred embodiment of the process according to the invention, drying in step A3 occurs at least partially by contact with hot air, by infrared radiation or by microwave radiation. Drying by direct contact with a heated surface is also possible, however it is less preferred because in this respect the thickness of the hydroentangled felt may decrease.

The hydroentangled felt produced according to this process should be suitable for use in segments for smoking articles. This means that it may in particular have all the characteristics, individually or in combination, that were described above in relation to the hydroentangled felt and have been defined in the claims directed to the hydroentangled felt.

In an advantageous development, said step A1 of providing the fiber web includes the following partial steps B1 to B3:

B1 - produce an aqueous suspension comprising cellulose fibers,

B2 - apply the suspension from stage B1 to a rotating sieve,

B3 - dehydrate the suspension through the rotating sieve to form the mentioned fiber band,

wherein in step B1 the amount or proportion of cellulose fibers is selected so that the hydroentangled felt contains at least 50% and at most 100% of cellulose fibers, with respect to the mass of the hydroentangled felt, after drying in step A3, and wherein in step B3, the direction of movement of the sieve defines said machine direction of the fiber web and said transverse direction is defined by the direction orthogonal to it in the plane of the fiber web , and

wherein in step B2 the suspension is applied to the rotating screen with a speed that is less than the speed of the rotating screen. In this regard, the speeds of the rotating sieve and the suspension must be understood in each case in relation to the same reference system, so that speeds different from each other lead to a relative speed between the suspension and the rotating sieve, which is used in this embodiment of the procedure.

In this embodiment of the process, the fiber web is at least partially given the desired structure by appropriate coordination between the speed at which the suspension flows over the rotating screen in step B2 and the speed of the rotating screen in stage B2. In particular, according to the inventors' findings, the speed with which the suspension flows over the rotating screen in step B2 should be less than the speed of the rotating screen. Due to the difference in speed, the slurry is dragged across the sieve and shear forces arise in the slurry, which align the cellulose fibers in the machine direction and thus contribute to a hydroentangled felt structure, which leads to plastic deformability of the according to the invention in the transverse direction. The person skilled in the art can determine the magnitude of the speed difference based on his experience and based on exemplary embodiments or by simple experiments. According to the experience of the inventors, in many cases a structure with the desired plastic deformability in the transverse direction can be achieved if, in step B2, the suspension is applied to the rotating sieve with a speed that amounts to only approximately 90% of the rotary sieve speed, for example between 88% and 93% of the rotary sieve speed. However, this indication only serves as a reference point, an adequate numerical value of the differential speed will depend at least partially on the other parameters of the process, so the expert in the field will determine it experimentally in practice, where as a guideline The final decisive criterion is the resulting characteristic plastic deformability of the thus produced hydroentangled felt in the transverse direction, which is characterized as described above with reference to the tensile test in the transverse direction according to ISO 1924-2:2008.

In a preferred development, the aqueous suspension in step B1 has a solids content of at most 3.0%, particularly preferably at most 1.0%, very particularly preferably at most 0.2%. and in particular a maximum of 0.05%. The particularly low solids content of the suspension allows a band of low-density fibers to form in stage B3, which has a positive impact on the filtration efficiency of a segment made from it.

In a preferred embodiment, the rotating screen of steps B2 and B3 is inclined upwards at an angle of at least 3° and at most 40°, particularly preferably at an angle of at least 5° and at most 30°. ° and very particularly preferably at an angle of at least 15° and at most 25°, with respect to the horizontal in the direction of travel of the fiber web.

In a preferred embodiment, the method comprises a step in which a pressure difference is generated between the two sides of the rotating sieve to promote dehydration of the suspension in step B3, where the pressure difference is generated so especially preferably by means of vacuum boxes or suitably shaped pallets.

In a preferred embodiment, the process comprises an additional step in which the one or more additives are applied to the fiber web. The additives are preferably selected from the group consisting of alkyl ketene dimers (AKD), acid anhydrides such as alkenyl succinic anhydrides (ASA), polyvinyl alcohol, waxes, fatty acids, starch, starch derivatives, carboxymethyl cellulose, alginates, chitosan , wet strength agents or substances for adjusting the pH value, such as for example organic or inorganic acids or bases, and mixtures thereof. Alternatively or additionally, one or more additives can also be applied, which are selected from the group consisting of citrates, such as trisodium citrate or tripotassium citrate, malates, tartrates, acetates, such as sodium acetate or potassium acetate, nitrates. , succinates, fumarates, gluconates, glycolates, lactates, oxalates, salicylates, a-hydroxycaprylates, phosphates, polyphosphates, chlorides and bicarbonates, and mixtures thereof.

In a preferred embodiment, the application of the additive or additives is carried out between steps A2 and A3 of the process according to the invention or after step A3, followed by another step of drying the strip of fibers.

Brief description of the figures

Figure 1 shows an exemplary force-deformation diagram of a hydroentangled felt according to the invention.

Figure 2 shows an exemplary force-deformation diagram of a filter material not according to the invention.

Figure 3 shows a device by means of which a process according to the invention can be carried out for the production of a hydroentangled felt according to the invention.

Figure 4 shows force-deformation curves measured in transverse direction in embodiment examples A, B and C according to the invention.

Figure 5 shows force-deformation curves measured in transverse direction in comparative example Z, not according to the invention.

Description of preferred embodiments and a comparative example

Some preferred embodiments of the hydroentangled felt, the processes for producing the hydroentangled felt, the smoking article segment and the smoking article are described below. Furthermore, a comparative example not according to the invention is described.

Examples of realization A, B and C

For the production of embodiments A, B and C according to the invention, the device shown in Figure 3 was used.

A suspension 31 of cellulose pulp fibers and regenerated cellulose fibers was provided in a storage container 32, step B1, and from there it was pumped to a rotating screen 33 inclined upward with respect to the horizontal, step B2, and dehydrated by means of vacuum boxes 39, step B3, so that a band of fibers 34 was formed on the screen, the general direction of movement of which is indicated by arrow 310. Note that steps B1 to B3 are specific partial steps of step of general procedure A1 (providing a fiber web comprising cellulose fibers). In this regard, the speed at which the sieve 33 moves was chosen to be approximately 10% greater than the speed of the slurry 31 flowing out of the storage container 32 to orient the fibers primarily in the machine direction. The fiber web 34 was removed from the screen 33 and transferred to an equally rotating support screen 35. There, water jets 311 arranged in several rows transversely to the machine direction of fiber web 34 were directed from the devices 36 onto the fiber web 34 to swirl the fibers and compact the fiber web 34 to give a felt, step A2. . Following step A2, the water jets 312 were also directed onto the other side of the fiber web 34 by additional devices 37. The still wet felt was then passed through drying equipment 38 and dried there, step A3, to obtain the hydroentangled felt.

To produce the hydroentangled felt, a mixture of softwood pulp fibers and Lyocell® fibers was used, where the fiber amounts were selected so that the finished hydroentangled felt consisted of 65% pulp fibers. cellulose and 35% Lyocell® fibers. The finished hydroentangled felt had a grammage, according to ISO 536:2019, of 55 g/m2.

In step A2 of the production process, three rows of water jets, 311 in Figure 3, were first directed at the first side of the fiber web 34 and then one row of water jets, 312 in Figure 3, at the first side of the fiber web 34. second side of the fiber web 34. The pressure of the water jets was varied in this regard between 2 MPa and 40 MPa in three stages (low, medium, high) to obtain different hydroentangled felts A, B and C according to the invention. The diameter of the openings through which the water jets came out varied in the rows and was selected between 80 pm and 120 pm, the distance between the openings from the center point to the center point amounted to 0.3 mm.

Samples of these hydroentangled felts were taken in the transverse direction and the force-deformation diagram was recorded in a tensile test according to ISO 1924-2:2008. The result is represented in figure 4. The elongation in % is represented on the x-axis 40, while the force in N is represented on the y-axis 41. The three lines marked A, B and C show the force diagrams -deformation of the three hydroentangled felts A, B and C according to the invention. As an example, the determination of the non-linear component of the strain energy absorbed up to half the elongation at break in the total strain energy absorbed up to half the elongation at break for the hydroentangled felt C is explained.

At half the elongation at break £b/2 the corresponding force F(£b/2) is determined and from this the linear proportion of the strain energy Elin can be calculated by

The total strain energy E absorbed up to half the elongation at break corresponds to that of the area spanned from the x axis 40 and the curve C from £=o to £=£<b>/2 and can be easily determined with sufficient precision by numerical integration procedures. If the linear proportion of the strain energy E<lin> is extracted from this, the surface shown as hatched is left, which corresponds to the non-linear component of the strain energy E<nl>.

The determination of the strain energies up to half of the elongation at break was carried out for the three hydroentangled felts A, B and C and the results are indicated in Table 1, where E means the total strain energy, E< lin>the linear proportion of the strain energy and E<nl>the non-linear component of the strain energy in each case in the transverse direction up to half the elongation at break. The strain energies were determined numerically from the force-strain curve and formally have the unit N-%. To correspond to the usual unit J/m<2>, the geometry of the sample must still be taken into account. However, since the only thing that matters in this case is that the relationships between them and the geometries of the sample are identical, this is dispensed with. The elongation at break £<b>and the force at half elongation at break F(£<b>/2) are also indicated.

Table 1

The values in Table 1 show that in embodiments A, B and C according to the invention there is a non-linear component of the strain energy of about 20% to about 30%. It can also be observed that as the pressure of the water jets increases, the elongation at break decreases. For this reason, it may be advantageous to choose a low water jet pressure, since, in addition to good plastic extension behavior, even greater permanent deformations are possible during curling.

Comparative example D

Comparative example D refers to the production of a filter material in a process that only contains steps B1 to B3 and A3, but not the hydroentanglement step of the fiber web. The filter material of Comparative Example D is not according to the invention because it is not a hydroentangled felt. Comparative example D essentially serves to demonstrate that the implementation of process steps B1 to B3 (as partial steps of a preferred embodiment of process step A1) are in fact suitable for contributing to a structure leading to deformability. Desired plastic characteristic in the transverse direction, when in step b2 the slurry is applied to the rotating sieve with a reduced speed.

To produce the filter material, a mixture of softwood cellulose pulp fibers and Lyocell® fibers was used, where the fiber amounts were selected so that the finished filter material consisted of 80% fibers. of cellulose pulp and 20% Lyocell® fibers. The finished filter material had a weight, according to ISO 536:2019, of 15 g/m2.

In step B2 of the procedure, the speed of the slurry flowing out was selected approximately 10% lower than the speed of the rotating screen.

Four samples of the filter material D thus obtained were taken in the transverse direction and the force-deformation diagram was recorded in a tensile test according to ISO 1924-2:2008. The evaluation of the force-deformation diagrams was carried out analogously to embodiment examples A to C. The results of the four measurements are shown in Table 2.

Table 2

The values in Table 2 show that, in the case of the filter material D thus produced, a non-linear component of the strain energy of approximately 30% is present and that repeated measurements on the same sample material show a small scatter . This demonstrates that process steps B1 to B3 actually contribute to the desired plastic deformability in the transverse direction when the slurry is applied to the rotating screen with reduced speed in step B2.

Implementation example E

On the other hand, the special embodiment of step A1 used in embodiment examples A to C (with reduced application speed of the suspension in step B2) is not necessary to obtain the characteristic plastic deformability according to the invention in the transverse direction in the hydroentangled felt. This is evident from the embodiment example E described below.

To produce the hydroentangled felt, a mixture of softwood cellulose pulp fibers and Lyocell® fibers was used in embodiment E, where the amounts of fiber were selected so that the finished hydroentangled felt consisted of the 80% cellulose pulp fibers and 20% Lyocell® fibers. Step A1 was carried out without first giving the cellulose pulp fibers in the fiber web a direction preferably transversely to the machine direction by performing step B2. The finished hydroentangled felt had a weight, according to ISO 536:2019, of 15 g/m2.

Step A2 of hydroentanglement is carried out like step A2 of embodiment B.

Two samples of the hydroentangled felt E thus obtained were taken in the transverse direction and the force-deformation diagram was recorded in a tensile test according to the ISO 1924-2:2008 standard. The evaluation of the force-deformation diagrams was carried out analogously to embodiment examples A to C. The results of the two measurements are shown in Table 3.

Table 3

The values in Table 3 show that in the case of the hydroentangled felt E produced in this way, a non-linear strain energy proportion of approximately 17% is present. Comparison with embodiment examples A to C, which were produced by combining a suitable realization of hydroentanglement in step A2 and a pre-restructuring of the fiber web by reduced application speed in step B2, shows that this combination allows higher proportions of nonlinear strain energy from about 22% to about 28% and can therefore lead to better behavior during crimping. Naturally, the stress of the combined process is somewhat greater than if, as in embodiment E, the characteristic plastic deformability according to the invention in the transverse direction is only obtained by properly carrying out the hydroentanglement in step A2. Embodiment example E demonstrates that this is actually possible.

Comparative example Z

To produce a filter material not according to the invention, the same fiber mixture was used as in embodiment D. The grammage was also 15 g/m2, but only machine settings that are customary in the production of conventional filter papers.

Three samples of the filter material of comparative example Z were taken in the transverse direction and the force-deformation diagram was recorded in a tensile test according to ISO 1924-2:2008. The evaluation of the force-deformation diagrams was carried out analogously to embodiment examples A to C. The results of the three measurements are shown in Table 4.

Table 4

The force-deformation curves of the comparative example Z are shown in Figure 5. Even without a quantitative analysis, it can already be distinguished that the behavior is clearly closer to a linear elastic behavior, so that the deformations are essentially reduced by new when unloaded and much larger deformations and forces are needed to achieve permanent deformations. In this regard, the breaking load or the breaking elongation in the transverse direction can be easily overcome.

Production of smoking segments and articles

Paper-wrapped filter rods with a length of 100 mm and a diameter of 7.85 mm were manufactured from each hydroentangled felt of embodiments A to C and E and the filter material of comparative example Z. The web width of the hydroentangled felt or filter material and the machine settings during filter production were selected in this regard so that a tensile strength of 450 ± 10 mmWG was obtained.

Filter rods could be produced from the hydroentangled felts of embodiments A to C and E and the filter material of comparative example Z. However, during production it is shown that in the case of the hydroentangled felts of embodiments A to C and E, the crimping process was significantly less sensitive to changes in machine settings and in particular to the setting of the distance between the rollers during curling than in comparative example Z.

Filter cigarettes were produced from the segments of embodiments A to C and E and comparative example Z by a conventional state-of-the-art process. This manufacturing process went smoothly.

Therefore, it is shown that from the hydroentangled felt according to the invention segments and smoking articles can be manufactured more efficiently and simply than from conventional hydroentangled felts or papers and that a better result can be achieved in the curly due to favorable plastic extension behavior.

Claims (15)

1. Hydroentangled felt for the production of a segment for a smoking article, wherein the hydroentangled felt is web-shaped and contains at least 50% and at most 100% cellulose fibers, in each case with respect to the mass of hydroentangled felt, wherein the hydroentangled felt has a weight of at least 15 g/m2 and at most 60 g/m2, wherein the hydroentangled felt has a machine direction and a transverse direction that is orthogonal to it in the plane of the felt band hydroentangled, and wherein the hydroentangled felt has a characteristic plastic deformability in the transverse direction, which is characterized in that, in a tensile test in the transverse direction according to ISO 1924-2:2008, the nonlinear component of the Strain energy absorbed by the hydroentangled felt up to half the elongation at break is at least 10% and at most 50% of the total strain energy absorbed by the hydroentangled felt up to half the elongation at break. 2. Hydroentangled felt according to claim 1, wherein the proportion of cellulose fibers in the hydroentangled felt is at least 60% and at most 100%, preferably at least 70% and at most 95%, in each case with respect to the mass of the hydroentangled felt. 3. Hydroentangled felt according to claim 1 or 2, wherein the cellulose fibers are formed by cellulose pulp fibers, regenerated cellulose fibers or mixtures thereof, wherein the cellulose pulp fibers are preferably obtained from coniferous wood or coniferous wood, wood from broadleaved trees or wood from broadleaved trees or other plants, in particular hemp, flax, jute, ramie, kenaf, kapok, coconut, abaca , sisal, bamboo, cotton or esparto grass; or are formed by a mixture of cellulose pulp fibers of different types of origin, and/or wherein the proportion of regenerated cellulose fibers is preferably at least 5% and at most 50%, preferably at least 10% and at most 45% and particularly preferably at least 15% and at most 40%, in each case with respect to the mass of the hydroentangled felt, and/or wherein the regenerated cellulose fibers are preferably formed at least partially by viscose fibers, modal fibers, Lyocell® fibers, Tencel® fibers or mixtures thereof. 4. Hydroentangled felt according to one of the preceding claims, whose weight is at least 18 g/m2 and at most 55 g/m2, preferably at least 20 g/m2 and at most 50 g/m2, and/or wherein the hydroentangled felt presents a characteristic plastic deformability in the transverse direction, which is characterized in that, in the tensile test mentioned in the transverse direction according to the ISO 1924-2:2008 standard, the non-linear component of the energy of deformation absorbed by the hydroentangled felt up to half the elongation at break is at least 15% and at most 40%, preferably at least 15% and at most 35%, and in particular at least 18% and as maximum of 32% of the total strain energy absorbed by the hydroentangled felt up to half the elongation at break, and/or wherein at least a portion of the cellulose fibers is loaded with a filler material, wherein the filler material is preferably formed by mineral particles, in particular calcium carbonate particles. 5. Hydroentangled felt according to one of the preceding claims, wherein the thickness of a layer of the hydroentangled felt, measured according to ISO 534:2011, is at least 25 pm and at most 1000 pm, preferably at least 30 pm and at most 800 pm and especially preferably at least 35 pm and at most 600 pm, and/or wherein the tensile strength with respect to the width of the hydroentangled felt in the transverse direction, measured according to ISO 1924-2:2008, is at least 0.05 kN/m and at most 5 kN/m, preferably at least 0.07 kN/m and at most 4 kN/m, and/or wherein the elongation at break of the hydroentangled felt in the transverse direction, measured according to ISO 1924-2:2008, is at least 0.5% and a maximum of 50%, preferably at least 0.8% and a maximum of 40%. 6. Segment for a smoking article, comprising a hydroentangled felt pressed together in a transverse direction and a wrapping material, wherein the hydroentangled felt contains at least 50% and at most 100% cellulose fibers, in each case with respect to the mass of the hydroentangled felt, wherein the hydroentangled felt has a weight of at least 15 g/m2 and at most 60 g/m2, wherein the hydroentangled felt has a transverse direction in which the hydroentangled felt has been pressed together in a transverse direction, and wherein The hydroentangled felt in the non-pressurized state in the transverse direction exhibits a characteristic plastic deformability in the transverse direction, which is characterized in that, in a tensile test in the transverse direction according to ISO 1924-2:2008, The non-linear component of the strain energy absorbed by the hydroentangled felt up to half the elongation at break is at least 10% and at most 50% of the total strain energy absorbed by the hydroentangled felt up to half the elongation at break. rip. 7. Segment according to claim 6, wherein the hydroentangled felt has one or more of the additional characteristics that have been defined in claims 2 to 5 and/or wherein the segment is cylindrical with a diameter of at least 3 mm and at most 10 mm, preferably at least 4 mm and at most 9 mm and especially preferably at least 5 mm and at most 8 mm, and/or where the segment has a length of at least 4 mm and at most 40 mm, preferably at least 6 mm and at most 35 mm and particularly preferably at least 10 mm and at most 28 mm. 8. Segment according to one of claims 6 or 7, wherein the tensile strength of the segment according to ISO 6565:2015 per segment length is at least 1 mmWG/mm and at most 12 mmWG/mm, and preferably at least 2 mmWG/mm and at most 10 mmWG/mm, and/or whose wrapping material is formed by a paper or a film and/or whose wrapping material has a grammage in accordance with ISO 536:2019 of at least 20 g/m2 and a maximum of 150 g/m2, preferably of at least 30 g/m2 and maximum 130 g/m2. 9. Method for the production of a segment according to one of claims 6 to 8, in which a hydroentangled felt according to one of claims 1 to 5 is curled or folded, a preferably endless strand of curled or folded hydroentangled felt is formed, The crimped or folded hydroentangled felt strand is wrapped with a wrapping material and the wrapped strand is cut into individual rods of defined length. 10. Smoking article comprising a segment containing an aerosol-forming material and a segment according to one of claims 6 to 8, wherein said segment according to one of claims 6 to 8 preferably forms the segment of the smoking article located closest to the end of the mouth, where the smoking article is in particular a filtered cigarette and the aerosol-forming material is or contains tobacco, or wherein the smoking article is in particular a smoking article, in the intended use of which the aerosol-forming material is only heated but not burned, wherein the aerosol-forming material preferably comprises a material selected from group consisting of tobacco, reconstituted tobacco, nicotine, glycerol, propylene glycol or mixtures thereof, wherein the aerosol-forming material is preferably present in liquid form and is located in a corresponding container in the smoking article. 11. Procedure for the production of a hydroentangled felt, where the procedure includes the following steps: A1 - provide a web of fibers comprising cellulose fibers, which has a machine direction and a transverse direction orthogonal to it which is in the plane of the web, A2 - hydroentangle the fiber web by directing water jets on the fiber web to produce a hydroentangled fiber web, A3 - dry the hydroentangled fiber web, wherein in step A1 the proportion of cellulose fibers in the fiber web is selected such that the hydroentangled felt contains after drying in step A3 at least 50% and at most 100% cellulose fibers, with respect to the mass of the hydroentangled felt, and wherein steps A1 and A2 are carried out so that the hydroentangled felt is given a characteristic plastic deformability in the transverse direction, which is characterized in that, in a tensile test in transverse direction according to the ISO 1924-2 standard :2008 performed on the hydroentangled felt after drying in step A3, the non-linear component of the strain energy absorbed by the hydroentangled felt up to half of the elongation at break is at least 10% and at most 50% of the total strain energy absorbed by the hydroentangled felt up to half the elongation at break, and where the hydroentangled felt after drying in step A3 has a weight of at least 15 g/m2 and at most 60 g/m2. 12. Method according to claim 11, wherein a plurality of water jets are used to carry out the hydroentanglement in step A2, wherein the water jets are arranged in at least one row transversely to the machine direction. of the fiber band, where the hydroentanglement is produced in step A2 preferably by means of at least two rows of water jets directed on the fiber band, where preferably on each of the two sides of the fiber band it acts minus a row of water jets. 13. Method according to one of claims 11 or 12, wherein the drying in step A3 occurs at least partially by contact with hot air, by infrared radiation or by microwave radiation, and/or wherein the hydroentangled felt produced according to this process is a hydroentangled felt according to one of claims 1 to 5. 14. Method according to one of claims 11 to 13, wherein step A1 of providing the fiber web comprises the following partial steps B1 to B3: B1 - produce an aqueous suspension comprising cellulose fibers, B2 - apply the suspension from stage B1 to a rotating sieve, B3 - dehydrate the suspension through the rotating sieve to form the mentioned fiber band, wherein in step B1 the amount or proportion of cellulose fibers is selected such that the hydroentangled felt contains after drying in step A3 at least 50% and at most 100% cellulose fibers, with respect to the mass of the hydroentangled felt, wherein the mentioned machine direction of the fiber web is defined by the direction of movement of the sieve in step B3 and the mentioned transverse direction is defined by the direction orthogonal to it which is found in the plane of the fiber web, and wherein in step B2 the suspension is applied onto the rotary sieve with a speed that is less than the speed of the rotary sieve, wherein the aqueous suspension in step B1 preferably has a solids content of at most 3.0% , particularly preferably at most 1.0%, most preferably at most 0.2% and in particular at most 0.05%, and/or wherein preferably the rotating screen of steps B2 and B3 is inclined upwards in the machine direction of the fiber web with respect to the horizontal at an angle of at least 3° and at most 40°, particularly preferably in an angle of at least 5° and at most 30° and particularly preferably at an angle of at least 15° and at most 25° and/or which preferably further comprises a stage in which a pressure difference is generated between the two sides of the rotating sieve to promote dehydration of the suspension in stage B3, where the pressure difference is generated especially preferably by means of vacuum boxes or appropriately formed pallets. 15. Method according to one of claims 11 to 14, comprising an additional step in which one or more additives are applied to the fiber web, wherein the one or more additives is selected from the group to be constituted. by alkyl ketene dimers (AKD), acid anhydrides, in particular alkenyl succinic anhydrides (ASA), polyvinyl alcohol, waxes, fatty acids, starch, starch derivatives, carboxymethyl cellulose, alginates, chitosan, wet strength agents and substances to adjust the pH value, in particular organic or inorganic acids or bases, and mixtures thereof, and/or comprising an additional step in which one or more additives are applied to the fiber web, wherein the one or more additives is selected from the group consisting of citrates, in particular trisodium citrate or tripotassium citrate , malates, tartrates, acetates, in particular sodium acetate or potassium acetate, nitrates, succinates, fumarates, gluconates, glycolates, lactates, oxalates, salicylates, a-hydroxycaprylates, phosphates, polyphosphates, chlorides and bicarbonates, and mixtures thereof , where The one or more additives are preferably applied between steps A2 and A3, or after step A3, followed by an additional step of drying the fiber web.