JP2023534469A - Pleated filter material for smoking articles - Google Patents

Abstract

A filter material for making a segment of a smoking article is described, the filter material comprising a hydroentangled nonwoven, the nonwoven comprising fibers, the fibers consisting of pulp fibers, regenerated cellulose fibers, and mixtures thereof. together, these fibers are contained in the nonwoven in an amount of at least 50% and up to 100% of the mass of the hydroentangled nonwoven, the nonwoven being in the form of a web, the running of the web It has an oriented longitudinal direction, a lateral direction perpendicular to the longitudinal direction and extending in the plane of the web, and a thickness direction perpendicular to the longitudinal direction and the lateral direction. such that the nonwoven has, in the plane formed by the transverse direction and the thickness direction, a wavy structure having a wave height of at least 50 μm and at most 1000 μm and a wavelength (22, 32, 42) of at least 150 μm and at most 5000 μm molded.

Description

The present invention relates to a filter material suitable for manufacturing segments of smoking articles, the filter material being pleated such that segments for smoking articles can be manufactured from the filter material in an efficient manner. The present invention also relates to segments for smoking articles made from this filter material.

The smoking article is typically a rod-shaped article consisting of at least two rod-shaped segments arranged next to each other. One segment comprises a material capable of forming an aerosol upon heating and at least one further segment serves to influence the properties of the aerosol.

The smoking article may be a filter cigarette in which a first segment contains an aerosol-forming material, particularly tobacco, and a further segment is designed as a filter and acts to filter the aerosol. In this regard, the aerosol is produced by combustion of the aerosol-forming material, and the filter serves primarily to filter the aerosol and to provide the filtered cigarette with a defined draw resistance.

However, the smoking article may also be what is known as a heated tobacco product, in which the aerosol-forming material is only heated and not combusted. This means that the number and amount of substances in the aerosol that are harmful to health are reduced. Such smoking articles also consist of at least two, more often more, especially four segments. One segment contains an aerosol-forming material, typically comprising tobacco, reconstituted tobacco, or tobacco prepared by other processes. Additionally, optional segments of the smoking article may serve to transport the aerosol, cool the aerosol, or filter the aerosol.

The segments are usually wrapped in packaging material. Very often paper is used as packaging material.

Unless explicitly stated below or directly apparent from the context, a "segment" does not include an aerosol-forming material, but rather a segment of a smoking article that serves, for example, to transport, cool, or filter aerosols. should be understood to refer to

It is known in the prior art to form such segments from polymers such as cellulose acetate or polylactide. After consumption of smoking articles, smoking articles must be disposed of in an appropriate manner. However, in many cases, consumers simply discard consumed smoking articles into the environment, and attempts to limit this behavior through summary prosecution or fines have met with little success.

Paper and cellulosic nonwovens are of increasing importance because cellulose acetate and polylactide biodegrade very slowly in the environment. During segment manufacture, a paper or cellulosic nonwoven web is first longitudinally pleated and then formed into a continuous rod and wrapped with wrapping material. The continuous rod is then cut into pieces suitable for further processing.

During pleating, the web passes over two patterned rollers, which emboss the pattern onto the web under high pressure. Typically, this pattern is a line pattern oriented in the direction of web travel. The embossed lines weaken the web in the transverse direction, perpendicular to the running direction, so that the web can be gathered in the transverse direction to form a continuous rod more easily.

However, due to the high pressure of the rollers during pleating, it can happen that the web is cut longitudinally, tearing during further processing, or causing other technical problems. Therefore, there is a need for a filter material that does not have this drawback, or to a lesser extent, but is otherwise identical as much as possible to other known filter materials.

DE 102005017478 A1 describes a tobacco smoke filter comprising fibers derived from regenerated cellulose (eg lyocell) and to which an adsorbent is added. More than one sorbent is added to the fibers of the tobacco smoke filter and/or the tobacco smoke filter contains sorbents between the fibers. This document states that such tobacco smoke filters allow obtaining high loadings of sorbent. In one embodiment, the nonwoven fabric was made from filled lyocell staple fibers. One nonwoven received a loading of 50% by weight of "Siralox 40" (Sasol Ltd.) in the lyocell fibers used in its manufacture. The other nonwoven received a loading of 50% by weight of HY-zeolite in its fibers. After adding activated carbon granules to one of the two nonwoven layers, the two layers were connected together by needling.

DE 102005017478 A1

It is an object of the present invention to provide a filter material for smoking articles which can be processed into segments of smoking articles with high productivity and which is otherwise as similar as possible to conventional filter materials in terms of its properties. is.

The object is to produce a filter material according to claim 1, a segment of a smoking article according to claim 17, a smoking article according to claim 24 and a filter material according to the invention according to claim 27. achieved by a process for Advantageous embodiments are provided in the dependent claims.

The inventors have found that the object is a filter material for manufacturing a segment of a smoking article, the filter material comprising a hydroentangled nonwoven fabric, the nonwoven fabric comprising fibers, the fibers being pulp fibers, regenerated cellulose fibers , and mixtures thereof, wherein the fibers together are present in the nonwoven in an amount of at least 50% and up to 100% by weight of the hydroentangled nonwoven, the nonwoven being a web having a longitudinal direction in the running direction of the web, a lateral direction extending in the plane of the web and orthogonal to the longitudinal direction, and a thickness direction orthogonal to the longitudinal direction and the lateral direction, and and a wavy structure having a wave height of at least 50 μm and a maximum of 1000 μm and a wavelength of at least 150 μm and a maximum of 5000 μm in the plane formed by the thickness direction. Found it.

Although the term "hydroentangled" first refers to the underlying manufacturing process, hydroentangled nonwovens are distinguished from other nonwovens and to our knowledge are obtained in the same way by other manufacturing processes. must be considered to have characteristic structural properties that cannot be For example, except in the case of paper, where strength is primarily caused by hydrogen bonding and the fibers are located primarily in the plane of the paper, the strength of hydroentangled nonwoven fabrics is obtained by entangling the fibers, and thus the fibers have a significant The proportions are also oriented through the thickness of the nonwoven.

During the production of the hydroentangled nonwoven fabric according to the present invention, fibers are deposited on a water permeable wire and consolidated by a plurality of laterally disposed water jets directed over the fibers. By special selection of the arrangement and properties of the water jets, according to the invention, it is possible to produce laterally wave-like structures similar to those that can also be obtained by pleating. Therefore, nonwovens and filter materials comprising nonwovens according to the invention are prepleated.

During the production of a continuous rod from filter material according to the invention, the filter material passes through two patterned rollers. Since the filter material according to the invention is already pre-pleated, substantially lower pressures are required to obtain sufficient pleating of the filter material, or pleating can even be omitted altogether. This greatly reduces the likelihood of accidentally cutting the filter material longitudinally. In this way, the number of interruptions during the production of continuous rods and segments can be reduced and productivity can be increased, which represents a substantial advantage of the filter material according to the invention.

Nonwovens are web-like and have a longitudinal direction in the running direction of the web and a direction perpendicular to the longitudinal direction and extending in the plane of the web, called the transverse direction. The direction perpendicular to the longitudinal and transverse directions is called the thickness direction. The nonwoven fabric contained in the filter material of the present invention has a cross-sectional area that is a corrugated structure in the plane defined by the transverse direction and the thickness direction, where the wavelength extends substantially transversely and the corrugation height extends substantially in the thickness direction. According to the invention, the wave height is at least 50 μm and at most 1000 μm, preferably at least 100 μm and at most 900 μm, particularly preferably at least 150 μm and at most 800 μm. According to the invention, the wavelength is at least 150 μm and at most 5000 μm, preferably at least 300 μm and at most 4000 μm, particularly preferably at least 500 μm and at most 2000 μm.

The shape of the undulations is not particularly critical, but must be sufficiently strong and pronounced to laterally gather the nonwoven more easily than the same nonwoven without the undulations. Due to the manufacturing process, the crest height and wavelength can also vary substantially within the cross-sectional area. This is not critical to the effect according to the invention as long as the wavelength and wave height are within the indicated ranges over a large portion of the cross-sectional area, in particular at least 60%, preferably at least 75% of the cross-sectional area.

The wavy structure also need not be prominent on the top and bottom sides of the nonwoven, whereby the thin areas created in the troughs of the waves facilitate lateral gathering of the nonwoven and thus pleats during segment manufacture. It is sufficient if it is pronounced on one side to reduce the pressure required for processing.

Surface roughness alone is generally not sufficient to achieve the effects according to the invention.

The wavy structure of a nonwoven can be determined by embedding a sample of the nonwoven in a suitable epoxy resin. After curing the epoxy resin, a sample can be ground or cut by a microtome at the cross-sectional plane of the nonwoven fabric so that the cross-sectional area is visible under an optical microscope. Optical microscopy makes it possible to visualize the wavy structure and measure the wave height and wavelength. A camera connected to the optical microscope can serve to record images of sections of the cross-sectional area.

The indicated conditions for crest height and wavelength are fully met for the present invention when met in a representative section of cross-sectional area. Because the manufacturing process causes the wavy structure to generally vary only slightly over the length of the nonwoven, such a cross-sectional area was measured for several cross-sectional areas in the lengthwise direction to test the requirements for crimp height and wavelength. No measurements need to be performed.

As an alternative to optical microscopy, scanning electron microscopy can also be used.

For good tensile strength of the segments produced from the filter material according to the invention and for adjustment of draw resistance or filtration efficiency, the hydroentangled nonwoven fabric is made of pulp fibers, fibers derived from regenerated cellulose, or The mixture is included in an amount of at least 50% and up to 100% by weight of the hydroentangled nonwoven. Preferably, the amount of fibers is at least 60% and at most 95%, respectively, by weight of the hydroentangled nonwoven.

Pulp fibers are preferably sourced from softwood, deciduous wood, or other plants such as hemp, flax, jute, ramie, kenaf, kapok, coconut, abaca, sisal, cotton, or African honeysuckle. Mixtures of pulp fibers of different origin can also be used. Particularly preferably, the pulp fibers are sourced from softwoods such as spruce, pine, or fir, because these fibers, due to their length, provide good strength in hydroentangled nonwovens. is. More particularly preferred are pulps sourced from softwoods, known as reinforcing pulps, which give particularly high strength, and mercerized pulps, which give especially high thicknesses and low densities.

Pulp fibers can be bleached or unbleached. Bleached pulp fibers, due to their white color, present advantages for the appearance of segments made from filter materials according to the present invention, whereas unbleached pulp fibers, which consequently have a light to dark brown color, It is more environmentally friendly as the bleaching process can be omitted. Mixtures of bleached and unbleached pulp fibers can also be used to better control the color of the filter material according to the invention.

The fibers derived from regenerated cellulose are preferably viscose fibres, modal fibres, Lyocell®, Tencel® or mixtures thereof. These fibers have good biodegradability, optimize the strength, thickness or density of the hydroentangled nonwoven fabric, and match the filtration efficiency of segments made therefrom to smoking articles. can be used.

In a more particularly preferred embodiment, the filter material according to the invention comprises a hydroentangled nonwoven, the hydroentangled nonwoven substantially exclusively but at least 95% by weight of the hydroentangled nonwoven comprising pulp fibers, regenerated cellulose derived fibers, or mixtures thereof. This more particularly preferred embodiment allows for very good biodegradability and rapid degradation on contact with water, while allowing a very low impact on the taste of smoking articles made from the filter material. do.

In a preferred embodiment of the filter material according to the invention, the hydroentangled nonwoven comprises at least 5% but less than 50%, particularly preferably less than 40%, more particularly preferably less than 30% short fibers of cellulose acetate, wherein Percentages are based on the weight of the hydroentangled nonwoven.

Alkenylketene dimers (AKD), alkenylsuccinic anhydrides (ASA), fatty acids, starches, starch derivatives, carboxymethylcellulose, alginates, or substances for adjusting pH, such as organic or inorganic acids or their salts or bases, etc. additives can be added to adjust specific properties of the nonwoven. A person skilled in the art can determine the type and amount of such additives from experience.

The basis weight of the hydroentangled nonwoven is preferably at least 25 g/m ² and at most 150 g/m ² , particularly preferably at least 35 g/m ² and at most 120 g/m ² , more particularly preferably at least 40 g/m ² . A maximum of 100 g/m ² . Basis weight affects the tensile strength of hydroentangled nonwovens, with higher basis weights may result in higher tensile strengths.

The thickness of the hydroentangled nonwoven is preferably at least 100 μm and at most 1000 μm, particularly preferably at least 120 μm and at most 800 μm, very particularly preferably at least 150 μm and at most 750 μm. Thickness affects the amount of filter material that can be packed into a segment of a smoking article, and thus the draw resistance and filtration efficiency of the segment, although greater thickness can make pleating of the filter material more difficult. Therefore, it also affects the processability of the filter material. The filter material according to the invention makes it possible to increase the thickness due to the corrugated structure of the nonwoven without causing problems during pleating. Therefore, the filter material according to the invention can be used particularly well when segments with high density and high suction resistance are produced. Thickness measurements are affected by the wavy structure of the material. However, for the purpose of determining thickness, the thickness measured in this way can also serve as a measure of how much filter material can be wound on a reel with a given diameter, so this Facts are ignored. The thickness is determined according to EDANA standard procedure NWSP 120.6. It can be measured according to R0(15).

The density of the hydroentangled nonwoven fabric can be obtained by dividing the basis weight by the thickness. The density of the hydroentangled nonwoven is preferably at least 50 kg/m ³ and at most 300 kg/m ³ , particularly preferably at least 70 kg/m ³ and at most 250 kg/m ³ , more particularly preferably at least 80 kg/m ³ and at most 220 kg/ ^m3 . These values relate to densities before smoking article segments are manufactured from filter materials according to the invention comprising this hydroentangled nonwoven. The density of a hydroentangled nonwoven fabric determines, among other things, the draw resistance and filtration efficiency of smoking article segments manufactured therefrom. Preferred ranges allow a good combination of draw resistance and filtration efficiency.

The mechanical properties of the hydroentangled nonwoven fabric are important to the processability of filter materials according to the present invention for smoking article segments. The tensile strength over the width of the hydroentangled nonwoven is preferably at least 0.05 kN/m and at most 5 kN/m, particularly preferably at least 0.07 kN/m and at most 4 kN/m.

The elongation to break of the hydroentangled nonwoven fabric is important when processing the filter material according to the present invention to produce segments of smoking articles, as the filter material is pleated, where a particularly high elongation to break is advantageous. In this regard, the wavy structure of the nonwoven allows a particularly high breaking elongation in the transverse direction and facilitates pleating during the production of the segments. The transverse breaking elongation of the hydroentangled nonwoven is preferably at least 1% and at most 50%, particularly preferably at least 3% and at most 40%.

Tensile strength and elongation at break can depend on the direction from which the sample for measurement is taken from the hydroentangled nonwoven. The requirements for tensile strength of hydroentangled nonwovens are fulfilled if the tensile strength in at least one direction is within the indicated, preferred or particularly preferred ranges. Elongation at break is indicated and is measured in the transverse direction.

A filter material according to the present invention comprises a hydroentangled nonwoven. Preferably, however, the hydroentangled nonwoven according to the invention constitutes the overwhelming majority of the filter material, so that preferably at least 80% of the mass of the filter material is formed by the hydroentangled nonwoven, particularly preferably At least 90% of the mass of the filter material is formed by the hydroentangled nonwoven.

Apart from the hydroentangled nonwoven, the filter material according to the invention may comprise further components that influence, for example, the processability of the filter material, or the properties of the segments made from the filter material, or the taste of the smoking article. . This includes, for example, perfumes, perfume carriers, impregnation of non-woven fabrics with filaments impregnated with perfumes, or substances that increase the stiffness of the filter material or materials that increase the hardness of filters made from the filter material.

In a preferred embodiment of the filter material according to the invention, the filter material is from the group consisting of hydroentangled nonwoven fabric and triacetin, glycol, propylene glycol, sorbitol, glycerol, polyethylene glycol, polyvinyl alcohol and triethyl citrate, or mixtures thereof. and one or more selected substances. These materials can assist in improving the tuning of the filtration efficiency to that of cellulose acetate.

If at least 90% of the mass of the filter material is formed by the hydroentangled nonwoven fabric, for example in terms of pulp fiber content, regenerated cellulose-derived fiber content, density, thickness, basis weight, tensile strength and elongation at break, Achieving the aforementioned characteristics of the hydroentangled nonwoven can also be tested on the filter material itself without the need to separate the hydroentangled nonwoven from the filter material. Accordingly, the above ranges and preferred, particularly preferred, and more particularly preferred ranges and properties according to the present invention are also valid for filter materials made from hydroentangled nonwovens.

Segments for smoking articles according to the invention can be manufactured from filter materials according to the invention using processes known in the art. These processes include, for example, pleating the filter material, forming a continuous rod from the pleated filter material, wrapping the continuous rod with a wrapping material, and wrapping the wrapped rod to a defined length. cutting into individual rods of length. In many cases, the length of such rods will be an integral multiple of the length of the segments to be used in smoking articles according to the present invention, so that the rods will have the desired length prior to or during manufacture of the smoking article. length segments.

A segment for smoking articles according to the invention comprises a filter material according to the invention and a wrapping material.

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, particularly preferably at least 4 mm and at most 9 mm, very particularly preferably at least 5 mm and at most 8 mm. These diameters are particularly advantageous for the use of 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, very particularly preferably at least 10 mm and at most 28 mm.

The draw resistance of the segment determines, among other things, what pressure differential the smoker needs to apply during consumption of the smoking article in order to generate a certain volumetric flow rate through the smoking article, and thus the smoker's substantially affect the acceptance of smoking articles by The pull resistance of the segment can be measured according to ISO 6565:2015 and is given in mm water gauge (mmWG). As a very good approximation, the drag resistance of a segment is proportional to its length, so drag resistance measurements can also be performed on rods that differ from the segments only in terms of their length. This makes it possible to easily calculate the attraction resistance of the segment.

The suction resistance of the segment per unit length of the segment is preferably at least 1 mmWG/mm and at most 12 mmWG/mm, particularly preferably at least 2 mmWG/mm and at most 10 mmWG/mm.

The packaging material for the segments according to the invention is preferably paper or foil.

The segment packaging material according to the invention preferably has a basis weight of at least 20 g/m ² and at most 150 g/m ² , particularly preferably at least 30 g/m ² and at most 130 g/m ² . A packaging material having this preferred or particularly preferred basis weight provides a particularly advantageous hardness to the segments according to the invention wrapped therewith. This avoids the possibility of a smoker accidentally crushing a segment of the smoking article.

In a preferred embodiment, the segment according to the invention further comprises at least one capsule containing perfume. Capsules are often designed so that the smoker can alter the taste of the smoking article by breaking it with finger pressure, thereby releasing flavoring agents.

Smoking articles according to the invention may be manufactured according to processes known in the art from segments according to the invention.

A smoking article according to the invention comprises a segment comprising an aerosol-forming material and a segment comprising filter material and packaging material according to the invention.

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

In preferred embodiments, the smoking article is a smoking article in which the aerosol-forming material is only heated and not combusted during its intended use.

A hydroentangled nonwoven fabric for filter material according to the present invention can be produced according to the following process according to the present invention, including steps AD below.
A - providing a fibrous web comprising fibers selected from the group consisting of pulp fibers, regenerated cellulose-derived fibers, and mixtures thereof;
B- hydroentangling the fibrous web by means of a plurality of water jets directed onto the fibrous web;
C--creating undulating structures in the nonwoven by means of a plurality of water jets directed over the fibrous web; and D--drying the hydroentangled nonwoven;
The proportion of said fibers in the fibrous web in step A is selected such that these fibers collectively comprise at least 50% and up to 100% of the weight of the dry hydroentangled nonwoven from step D. , the thickness of the fibrous web provided in step A perpendicular to the longitudinal direction forming the running direction of the fibrous web, the transverse direction perpendicular to the longitudinal direction and extending in the plane of the fibrous web, and the thickness perpendicular to the longitudinal direction and the transverse direction and the waterjets directed onto the fibrous web in step C are centered from the center point of the waterjets at the location of impingement on the fibrous web, where the waterjets are at least 150 μm and at most 5000 μm between each other. point and arranged such that the pressure of each water jet in step C is at least 2 MPa and at most 70 MPa, the non-woven fabric obtained in step D is at least 50 μm and at most 1000 μm. It has a wave-like structure in the plane formed by the lateral and thickness directions with a wave height and a wavelength of at least 150 μm and at most 5000 μm. In this specification and the rest of the disclosure, the "waterjet pressure" is conventionally the pressure in the pressure chamber used to generate the waterjet.

According to the inventors' findings, a waterjet with a sufficiently high pressure is suitable for creating depressions in the nonwoven fabric running under the waterjet, which can be perceived as wave troughs in the cross-sectional area. can. In this connection, a pressure of at least 2 MPa is required, which depends very substantially on the speed at which the fibrous web passes through the machine. Higher speeds require higher pressures. At correspondingly high pressures, the fibers are not only entangled, but partially displaced, contributing substantially to the formation of the wavy structure. Since the fibrous web is typically supported by the wires and the fibers are displaced primarily where the wires are permeable during treatment with the waterjet, the structure of the wires is preferably undulating as intended. It should be chosen to suit the structure.

In the prior art, during hydroentangling of the nonwoven, the water jets are not positioned at defined positions with respect to the fibrous web, but rather positioned such that uniform entangling can be achieved by the water jets over the entire area of the running fibrous web. It is However, this does not lead to the characteristic wavy structure of the filter material according to the invention, even when the pressure of the water jet exceeds 2 MPa.

Therefore, according to the invention, the water jets which are to serve to generate the wave-like structure are arranged accordingly such that particularly high-pressure water jets are not directed over the area of the fibrous web where wave crests are to be produced. It must be. Therefore, the waterjets that should serve to generate the wavy structure in step C are laterally offset from the center point of the waterjets at the location of their impingement on the fibrous web by at least 150 μm and up to 5000 μm. They are laterally spaced from each other to a central point. The water jets can be arranged arbitrarily in the longitudinal direction.

It is also possible to direct the water jets over both sides of the fibrous web to carry out steps B or C. Preferably, the water jets in step C are arranged so that they hit those areas that should form wave troughs from each side.

The pressure of the water jet that serves to entangle the nonwoven in step B can also exceed 2 MPa, and can be selected to be substantially higher, especially for higher velocity fibrous webs. According to the invention, the only important factor is that the effect of all water jets over the area of the fibrous web is not so uniformly distributed that it cannot produce a wavy structure.

According to the invention, the water jet for generating the wavy structure in step C requires a pressure of at least 2 MPa and a maximum of 70 MPa. According to the inventors' findings, pressures below 2 MPa cannot produce significant wavy structures, and pressures above 70 MPa risk cutting the fibrous web, even at higher speeds. Preferably, the water jet pressure in step C is at least 3 MPa and at most 40 MPa. The pressure for producing the wavy structure may depend on the velocity of the fibrous web, whereby preferably the ratio p/v between the pressure p (MPa) and the velocity v (m/s) of the fibrous web is:2. It is chosen such that 5≤p/v≤20, preferably 3≤p/v≤15.

Preferably, the water jet in step C exits through an opening having an area of at least 450 μm ² and up to 50000 μm ² and preferably a circular opening.

The pressure of the water jet in step B is preferably at least 0.5 MPa and at most 60 MPa, particularly preferably at least 1 MPa and at most 50 MPa; should be combined with The pressure for entangling the fibrous web may depend on the velocity of the fibrous web, whereby preferably the ratio p/v between pressure p (MPa) and velocity v (m/s) is 2≤p/v ≤10, preferably 4≤p/v≤8.

A wavy structure is characterized in that the wave height and wavelength can be detected in the cross-sectional area of the nonwoven. According to the invention, the wave height after step D is at least 50 μm and at most 1000 μm, preferably at least 100 μm and at most 900 μm, particularly preferably at least 150 μm and at most 800 μm. According to the invention, the wavelength after step D is at least 150 μm and at most 5000 μm, preferably at least 300 μm and at most 4000 μm, particularly preferably at least 500 μm and at most 2000 μm.

A hydroentangled nonwoven fabric produced according to this process should be suitable for use in the filter materials described above. This is particularly the case when the hydroentangled nonwoven has all the features described above individually or in combination in relation to the hydroentangled nonwoven as a component of the filter material and defined in the claims directed to the filter material. means that you can have

The fibrous web of step A can be provided using a variety of processes, such as wet-laid or air-laid processes.

In a preferred variant A1 of the process according to the invention, the fibrous web in step A is provided by a wetlaid process comprising substeps A1.1 to A1.3:
A1.1—A substep of producing an aqueous suspension comprising fibers selected from the group consisting of pulp fibers, regenerated cellulose fibers, and mixtures thereof, wherein the amount of fibers is , selected to be included in an amount of at least 50% and up to 100% of the mass of the dry hydroentangled nonwoven fabric from step D, substeps;
A1.2—the substep of applying the suspension from step A1.1 to the running wire, and
A1.3—sub-step of dewatering the suspension by a running wire to form a fibrous web;
The process preferably comprises a further sub-step A1.4:
A1.4—Sub-step of adjusting the moisture content of the fibrous web by drying or wetting.

In a preferred embodiment of variant A1 of the process according to the invention, the aqueous suspension in step A1.1 is at least 0.005% and at most 3.0%, preferably at least 0.005% and at most 1.0%. %, particularly preferably at least 0.01% and at most 0.2%, more particularly preferably at least 0.01% and at most 0.05%. A particularly low solids content suspension makes it possible to form an even lower density fibrous web in step A1.3.

In a preferred embodiment of the process variant A1 according to the invention, the running wires in steps A1.2 and A1.3 are at least 3° and at most 40°, preferably at least 5° and at most 30°, particularly preferably at least It is inclined upwards in the longitudinal direction of the fibrous web with respect to the horizontal by an angle of 15° and a maximum of 25°.

In a preferred embodiment of the process variant A1 according to the invention, the dewatering in step A1.3 is assisted by creating a pressure difference between the two sides of the running wire, the pressure difference preferably being a vacuum box or suitably Produced by molded vanes.

In a preferred embodiment of the process variant A1 according to the invention, the drying in step A1.4 is carried out by means of heated drying cylinders or hot air and the wetting is carried out by spray bars. The drying process or wetting serves to optimally adjust the moisture content of the fibrous web for hydroentangling in step B. Specifically, in step A1.4, the fibrous web can first be dried to approximately the equilibrium moisture content at normal room temperature and relative humidity, then the fibrous web is wound up and conveyed to a separate device that performs hydroentangling. , where it is unwound and the water content is adjusted for the next step B by means of a spray bar.

In a preferred variant A2 of the process according to the invention, the fibrous web in step A is provided by an airlaid process comprising steps A2.1 and A2.2:
A2.1—Producing a fibrous web by an airlaid process, the fibrous web comprising fibers selected from the group consisting of pulp fibers, regenerated cellulose fibers, and mixtures thereof, wherein the amount of these fibers is , these fibers are selected so that they together comprise an amount of at least 50% and up to 100% of the mass of the dry hydroentangled nonwoven fabric from step D, and A2.2—Fibrous web Wetting step.

Such an airlaid process of variant A2 may have advantages, for example, because the energy-intensive drying in step A1.4 of variant A1 can be omitted.

In a preferred embodiment of the process according to the invention, the drying in step D is carried out at least partially by contact with hot air, infrared radiation or microwave radiation. In a more particularly preferred embodiment of the process according to the invention the drying in step D is carried out by through-air drying. With this through-drying, also known in the technical field as TAD, the textile material is dried by forcing a stream of warm gas, in particular air, over the textile material. By this through-drying, a hydroentangled nonwoven fabric of the best quality can be obtained. Drying by direct contact with a heated surface is also possible but less preferred as doing so can destroy the wavy structure of the hydroentangled nonwoven.

1 shows an apparatus capable of carrying out the process according to the invention for producing hydroentangled nonwovens. As an example, the determination of the wave height and wavelength of the wavy structure of a nonwoven is shown. 1 shows a cross-sectional area of a nonwoven fabric for filter material according to the invention; Figure 2 shows a cross-sectional area of a filter material not according to the invention after pleating;

Several preferred embodiments of filter materials and processes for manufacturing hydroentangled nonwovens are described below.

To produce the hydroentangled nonwoven fabric contained in the filter material according to the invention, the process described below using the apparatus shown schematically in FIG. 1 was used.

An aqueous suspension 1 of fibers of pulp fibers and regenerated cellulose is pumped from a storage tank 2 onto a running wire 3, inclined upwards with respect to the horizontal and dewatered by a vacuum box 9, thereby forming a fibrous web 4 onto the wire. Formed, its general direction of movement is indicated by arrow 10 . The fiber web 4 was removed from the wire 3 and transferred to the supporting wire 5 which was also running. If desired, this transfer can be facilitated by pick-up rolls or by waterjet entangling the fibrous web prior to transfer. On the support wire 5, water jets 11 from the device 6, arranged in three rows transversely to the fibrous web 4, impinge the fibers in order to entangle the fibers and consolidate the fibrous web 4 to form a nonwoven fabric. I was directed to Web4. In a further step, a higher pressure water jet 12 was also directed over the fibrous web 4 by means of an additional device 7 in order to produce the wavy structure described above. In contrast to device 6, device 7 was set up so that both longitudinally successive rows of water jets 12 were directed to the same lateral position as much as possible. Thus, when viewed longitudinally, the second row of waterjets 12 is directed into the troughs of the waves produced by the first row of waterjets 12, thus reducing the wave-like structure produced by the first row. strengthened. An optional device 6a may direct additional water jets 11a onto the fibrous web, which, depending on placement and pressure, may serve to entangle the nonwoven as well as create or consolidate the wavy structure. . In contrast to the representation of FIG. 1, the water jets of device 6a may be directed onto fibrous web 4 from the same side as water jets 11 or 12. The still moist nonwoven then passed through a through-air dryer 8 and was dried there.

A mixture of 80% by weight pulp fibers and 20% by weight Lyocell® fibers was used to produce the hydroentangled nonwoven. Fiber entanglement was performed by three rows of water jets 11 generated at pressures of 3 MPa, 5 MPa and 6 MPa in the running direction. The wavy structure of the nonwoven fabric was produced by two rows of water jets 12, which were produced at a pressure of 8.5 MPa in both rows. The devices 7 for generating both rows of water jets 12 were each laterally separated by a distance of 2000 μm and had a diameter of 100 μm. The speed of the fibrous web was a relatively low 50 m/min. At higher speeds, the pressure of water jets 11 and 12 must be increased accordingly. For the ratio p/v of the pressure p (MPa) of the water jet for entangling the fibrous web to the velocity v (m/s) of the fibrous web, 3/(50/60) = 3.6 to 6/(50 /60)=7.2 was obtained. The ratio p/v between the pressure p of the water jet and the velocity (m/s) of the fibrous web to produce the wavy structure was 8.5/(50/60))=10.2.

For the nonwoven fabric produced thereby, the basis weight was determined to be 49.6 g/m ² and NWSP 120.6. The thickness according to R0(15) was 522 μm and the density was 95 kg/m ³ . The longitudinal tensile strength was 8.6 N/15 mm and the transverse elongation at break was 31%.

After embedding the non-woven fabric sample in epoxy resin and curing the epoxy resin, the sample was cut with a microtome so that cross-sections made in the transverse and thickness directions were visible with an optical microscope. Optical microscopy recorded cross-sectional images and measured the wavy structure in terms of crest height and wavelength.

FIG. 2 shows, by way of example, the determination of the crest height and wavelength of a corrugated structure of a nonwoven. If the nonwoven fabric 20 has a pronounced wavy structure on both sides, the wave height 21 is determined by the distance in the thickness direction 41 between the highest points of the wave crests 23 and the lowest points of the adjacent wave troughs 23 on the same side. be. Wavelength 22 is the lateral 40 distance between two points of equal phase angle of the wave structure, shown here by way of example as the distance between two adjacent wave crests 24 and 25 . If the nonwoven fabric 30 has a pronounced wavy structure on only one side, the wave height 31 is the same as the distance in the thickness direction 41 between the highest points of the wave crests 34 and the lowest points of the adjacent wave troughs 33 on the same side. determined by the method. Wavelength 32 is the lateral 40 distance between two points of the same phase angle of the wave-like structure, shown here by way of example as the distance between two adjacent wave crests 34 and 35 . The crest height or wavelength can be determined as a single value or as an average of several measurements, eg three measurements.

FIG. 3 shows an image taken of a cross-sectional area of the produced nonwoven fabric under an optical microscope. The wavy structure was clearly identifiable, the wave height 41 was determined to be 220 μm and the wavelength 42 was 2030 μm.

A nonwoven fabric was used as a filter material according to the invention without adding further components, from which segments of wrapping paper wrapped smoking articles having a basis weight of 78 g/m ² were produced. The production of the segments was possible without any problems, in particular the pleating could be carried out at substantially reduced pressure. In further experiments it was found that pleating could also be omitted entirely without having to reduce the production rate or substantially alter the properties of the segments.

For comparison, Figure 4 shows 100% pulp fibers after being pleated by mechanical pressure between two rolls during the manufacture of segments for smoking articles, but before segments are manufactured therefrom. Figure 2 shows a filter material not according to the invention consisting of paper made from , i.e. not a hydroentangled material. Cross-sectional samples were also analyzed with an optical microscope to measure wave height and wavelength using this filter material.

A similar wavy structure can be seen from FIG. 4, where again the wave height 51 was determined to be 390 μm and the wavelength 52 was 2000 μm. The wavy structure of the filter material according to the invention is similar to the wavy structure of the filter material not according to the invention after pleating, and therefore the pleating of the filter material according to the invention can be carried out with substantially less pressure. can be found, or can be omitted entirely.

These experiments demonstrate that the filter material according to the present invention facilitates or completely avoids the pleating step during the manufacture of segments for smoking articles compared to filter materials known in the prior art. , thus simplifying the manufacturing process and reducing susceptibility to error.

Claims (42)

A filter material for making a segment of a smoking article, said filter material comprising a hydroentangled nonwoven fabric (20, 30, 40), said nonwoven fabric (20, 30, 40) comprising fibers, said fibers comprising: selected from the group consisting of pulp fibers, regenerated cellulose fibers, and mixtures thereof, wherein the fibers together represent at least 50% and up to 100% of the weight of said hydroentangled nonwoven fabric (20, 30, 40); and the nonwoven fabric (20, 30, 40) is in the form of a web, and the longitudinal direction forming the running direction of the web and the longitudinal direction and a thickness direction perpendicular to the longitudinal direction and the transverse direction, and wherein the nonwoven fabric (20, 30, 40) extends in the transverse direction and in the plane of the web. To have a wavy structure in the plane formed by the thickness direction with a wave height (21, 31, 41) of at least 50 μm and up to 1000 μm and a wavelength (22, 32, 42) of at least 150 μm and up to 5000 μm. Molded, filter material. 2. Filter material according to claim 1, wherein the wave height (21, 31, 41) is at least 100 [mu]m and at most 900 [mu]m, preferably at least 150 [mu]m and at most 800 [mu]m. 3. Filter material according to claim 1 or 2, wherein the wavelengths (22, 32, 42) are at least 300 [mu]m and at most 4000 [mu]m, preferably at least 500 [mu]m and at most 2000 [mu]m. 2. The amount of pulp fibers, fibers of regenerated cellulose, or said mixture thereof, respectively, is at least 60% and at most 95%, based on said weight of said hydroentangled nonwoven fabric (20, 30, 40). 4. The filter material of any one of 3 through 3. said pulp fibers are sourced from soft wood, in particular spruce, pine or fir, deciduous wood, hemp, flax, jute, ramie, kenaf, kapok, coconut, abaca, sisal, cotton or African honeydew; 5. A filter material according to any one of claims 1 to 4, formed by a mixture of two or more different pulp fibers, or of these origins. 6. A filter material according to any one of the preceding claims, wherein the pulp fibers are at least partially formed by reinforcing pulp or mercerized pulp. 7. Any one of claims 1 to 6, wherein the fibers of regenerated cellulose are formed by viscose fibres, modal fibres, Lyocell®, Tencel® or mixtures thereof. filter material. The hydroentangled nonwoven fabric (20, 30, 40) comprises substantially exclusively but at least 95%, relative to said mass of said hydroentangled nonwoven fabric (20, 30, 40), pulp fibers, fibers of regenerated cellulose , or mixtures thereof. each of said hydroentangled nonwovens (20, 30, 40) of said filter material is at least 5% and less than 50%, preferably less than 40%, based on said mass of said hydroentangled nonwovens (20, 30, 30) 8. A filter material according to any one of the preceding claims, comprising, particularly preferably less than 30%, short fibers derived from cellulose acetate. The basis weight of said hydroentangled nonwoven fabric (20, 30, 40) is at least 25 g/m ² and at most 150 g/m ² , preferably at least 35 g/m ² and at most 120 g/m ² , particularly preferably at least 40 g/m 2 . 10. A filter material according to any one of the preceding claims, having a weight of ^m2 and up to 100 g/ ^m2 . 11. The method of claim 1, wherein the thickness of the hydroentangled nonwoven (20, 30, 40) is at least 100 μm and at most 1000 μm, preferably at least 120 μm and at most 800 μm, particularly preferably at least 150 μm and at most 750 μm. A filter material according to any one of the preceding paragraphs. The density of said hydroentangled nonwoven fabric (20, 30, 40) is at least 50 kg/m ³ and at most 300 kg/m ³ , preferably at least 70 kg/m ³ and at most 250 kg/m ³ , particularly preferably at least 80 kg/m ³ and up to 220 kg/m ³ . 4. The claim wherein the tensile strength over the width of the hydroentangled nonwoven (20, 30, 40) 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. 13. Filter material according to any one of clauses 1 to 12. 14. Any one of claims 1 to 13, wherein the hydroentangled nonwoven fabric (20, 30, 40) has an elongation to break in the transverse direction of at least 1% and at most 50%, preferably at least 3% and at most 40%. A filter material as described above. 15. A filter material according to any one of the preceding claims, wherein at least 80%, preferably at least 90% of said mass of said filter material is formed by said hydroentangled nonwoven (20, 30, 40). . 16. Any of claims 1 to 15, comprising one or more substances selected from the group consisting of triacetin, glycol, propylene glycol, sorbitol, glycerol, polyethylene glycol, polyvinyl alcohol, and triethyl citrate, or mixtures thereof. or the filter material according to claim 1. A segment comprising a filter material according to any one of claims 1 to 16 and a packaging material. 18. Segment according to claim 17, 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, particularly preferably at least 5 mm and at most 8 mm. 19. Segment according to claim 17 or 18, having a length of at least 4 mm and at most 40 mm, preferably at least 6 mm and at most 35 mm, particularly preferably at least 10 mm and at most 28 mm. 20. The segment according to any one of claims 17-19, having a suction resistance according to ISO 6565:2015 of at least 1 mmWG/mm and at most 12 mmWG/mm, preferably at least 2 mmWG/mm and at most 10 mmWG/mm. 21. A segment according to any one of claims 17-20, having a packaging material formed by paper or foil. 22. The packaging material according to any one of claims 17 to 21, having a grammage of at least 20 g/ ^m2 and at most 150 g/ ^m2 , preferably at least 30 g/ ^m2 and at most 130 g/ ^m2 . segment. 23. A segment according to any one of claims 17 to 22, comprising at least one capsule containing a perfume. A smoking article comprising a segment comprising an aerosol-forming material and a segment according to any one of claims 17-23. 25. The smoking article of Claim 24, wherein the smoking article is a filtered cigarette and the aerosol-forming material is formed by tobacco. 25. The smoking article of claim 24, wherein the aerosol-forming material is only heated and not combusted during intended use. A process for making a filter material for a smoking article comprising steps A-D of:
A - providing a fibrous web (4) comprising fibers selected from the group consisting of pulp fibers, regenerated cellulose-derived fibers, and mixtures thereof;
B- hydroentangling said fibrous web (4) by means of a plurality of water jets (11) directed over said fibrous web;
C- producing wavy structures in a nonwoven fabric (20, 30, 40) by means of a plurality of water jets (12) directed over said fibrous web;
D- drying the hydroentangled nonwoven (20, 30, 40);
the proportion of said fibers in said fibrous web in step A, these fibers together being at least 50% and up to 100% of the weight of said hydroentangled nonwoven (20, 30, 40) in dry state from step D; and the fiber web (4) provided in step A has a longitudinal direction forming the running direction of the fibrous web and a direction perpendicular to the longitudinal direction and in the plane of the fibrous web and a thickness direction perpendicular to said longitudinal direction and said transverse direction, said water jets (12) being directed onto said fibrous web in step C, said water jets (12) the lateral distance from the center point to the center point of the water jet at the location of impact on the fibrous web being at least 150 μm and at most 5000 μm between is at least 2 MPa and at most 70 MPa, and said nonwoven fabric (20, 30, 40) obtained in step D has a crest height (21, 31, 41) of at least 50 μm and at most 1000 μm, and a crest height (21, 31, 41) of at least 150 μm and having a wave-like structure in the plane formed by said lateral direction and said thickness direction, having a wavelength (22, 32, 42) of up to 5000 μm,
process. 28. Process according to claim 27, wherein the water jets (11, 11a, 12) for performing step B and/or step C are directed on both sides of the fibrous web. 29. A process according to claim 27 or 28, wherein the water jets (12) in step C are arranged such that the water jets (12) impinge on regions forming wave troughs viewed from each side. 30. According to any one of claims 27 to 29, wherein said water jet (12) in step C emerges from an opening having an area of at least 450 μm ² and up to 50000 μm ² and preferably being a circular opening. process. Said pressure of said water jet (12) in step C is at least 3 MPa and at most 40 MPa, and the pressure for producing said wavy structure is preferably equal to said pressure p (MPa) and said fiber web velocity v (m/s) ratio p/v selected depending on said speed of said fibrous web (4) such that 2.5≤p/v≤20, preferably 3≤p/v≤15 31. The process of any one of claims 27-30, wherein the pressure of said water jet (11) in step B is at least 0.5 MPa and at most 60 MPa, preferably at least 1 MPa and at most 50 MPa, said pressure in step B is preferably between said pressure p (MPa) and Said speed of said fibrous web (4) such that 2≦p/v≦20, preferably 4≦p/v≦8 for the ratio p/v to said speed v (m/s) of said fibrous web 32. A process according to any one of claims 27 to 31, selected according to. 33. Process according to any one of claims 27 to 32, wherein the wave height (21, 31, 41) after step D is at least 100 µm and at most 900 µm, preferably at least 150 µm and at most 800 µm. 34. Process according to any one of claims 27 to 33, wherein said wavelength (22, 32, 42) after step D is at least 300 μm and at most 4000 μm, preferably at least 500 μm and at most 2000 μm. The hydroentangled nonwoven fabric (20, 30, 40) obtained in step D is defined in claims 1 to 16 with respect to the hydroentangled nonwoven fabric (20, 30, 40) as a component of the filter material according to the claims. 35. A process as claimed in any one of claims 27 to 34, having any or any combination of the following features. In variant A1 of said process, said fibrous web (4) in step A is provided by a wet-laid process comprising the following substeps A1.1-A1.3:
A1.1—A substep of producing an aqueous suspension (1) comprising fibers selected from the group consisting of pulp fibers, fibers derived from regenerated cellulose, and mixtures thereof, wherein the amount of fibers is a substep wherein the fibers together are selected to comprise at least 50% and up to 100% of the mass of said hydroentangled nonwoven fabric (20, 30, 40) in its dry state from step D;
A1.2—a substep of applying said suspension (1) from step A1.1 to a running wire (3), and A1.3—by a running wire (3) to form a fibrous web (4) a substep of dewatering said suspension (1);
Said process preferably comprises a further sub-step A1.4:
A1.4—sub-step of adjusting the moisture content of said fibrous web (4) by drying or wetting;
36. The process of any one of claims 27-35. said aqueous suspension (1) in step A1.1 is at least 0.005% and at most 3.0%, preferably at least 0.005% and at most 1.0%, particularly preferably at least 0.01 % and up to 0.2%, more particularly preferably at least 0.01% and up to 0.05% solids. Said running wire (3) in steps A1.2 and A1.3 is at an angle of at least 3° and at most 40°, preferably at least 5° and at most 30°, particularly preferably at least 15° and at most 25° 38. A process according to claim 36 or 37, which is inclined upwards in said running direction of said fibrous web (4) from horizontal by . In step A1.3 dewatering is assisted by creating a pressure differential between the two sides of said running wire (3), said pressure differential being preferably created by a vacuum box or suitably shaped vanes. 39. The process of any one of claims 36-38, wherein 40. A process according to any one of claims 36 to 39, wherein said drying in step A1.4 is performed by heated drying cylinders or hot air and said wetting is performed by a spray bar. In a variant A2 of said process according to the invention, said fibrous web (4) in step A is provided by an airlaid process comprising the following substeps A2.1 and A2.2:
A2.1—A sub-step of producing a fibrous web by an airlaid process, said fibrous web (4) comprising fibers selected from the group consisting of pulp fibers, fibers derived from regenerated cellulose, and mixtures thereof; The amount of these fibers is such that they together comprise at least 50% and up to 100% of the weight of said hydroentangled nonwoven fabric (20, 30, 40) in its dry state from step D. selected substeps and
A2.2—sub-step of wetting said fibrous web,
36. The process of any one of claims 27-35. 42. Claims 27 to 41, wherein said drying in step D is at least partially performed by contact with hot air, by infrared radiation or by microwave radiation, said drying in step D being preferably performed by through-air drying. A process according to any one of

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