Patent Application
20250127208
The invention relates to a segment of a smoking article, wherein the segment comprises a filter material that enables the properties of the segment, in particular draw resistance and filtration efficiency, to be adjusted over a wide range in a simple and reliable manner. The filter material of the segment thereby comprises a calendered fibrous web with particular properties.
Smoking articles are typically rod-shaped articles, which consist of at least two rod-shaped segments disposed one after the other. One segment contains a material that is capable of forming an aerosol upon heating and at least one further segment contains a material that serves to influence the properties of the aerosol.
The smoking article can be a filter cigarette in which a first segment contains the aerosol-forming material, in particular tobacco, and in which a further segment is designed as a filter and acts to filter the aerosol. In this regard, the aerosol is generated by combustion of the aerosol-forming material and the filter serves primarily to filter the aerosol and to provide the filter cigarette with a defined draw resistance.
The smoking article, however, can also be what is known as a heated tobacco product, in which the aerosol-forming material is only heated but not burned. This means that the number and amount of substances in the aerosol which are damaging to health are reduced. Such a smoking article also consists of at least two, more often, however, of more, in particular of four segments. One segment contains the aerosol-forming material, which typically comprises tobacco, reconstituted tobacco or tobacco prepared by other processes or nicotine, glycerol or propylene glycol. Further, optional segments in the heated tobacco product sometimes serve to transfer the aerosol, to cool the aerosol or to filter the aerosol.
The segments are usually wrapped with a wrapper material. Very often, paper is used as wrapper material.
In the prior art it is known to form such segments from cellulose acetate or polylactides. Because polylactides, and in particular cellulose acetate, biodegrade only very slowly in the environment, the industry has an interest in manufacturing the segments of the smoking article from other materials that biodegrade better, and which allow the use of cellulose acetate to be dispensed with. It is known in the prior art to manufacture segments for smoking articles, in particular filter segments, from paper. Such segments are generally readily biodegradable, but also suffer from disadvantages. As an example, filter segments from paper generally have a high filtration efficiency and thus lead to a dry aerosol, which deteriorates the taste of the aerosol compared with cigarettes with conventional filter segments from cellulose acetate. Furthermore, they often have a lower filtration efficiency for phenols than cellulose acetate. Furthermore, it has been shown to be difficult to manufacture a segment from paper that is acceptable to the consumer as regards the combination of draw resistance, filtration efficiency and hardness. In order to reduce the filtration efficiency, less paper per unit volume of filter is often used, which, however, makes the segment soft and leads to too low a draw resistance.
When designing segments of smoking articles, the draw resistance and the filtration efficiency play an important role. For smoking articles, segments with a high draw resistance as well as with a low draw resistance and also with high or low filtration efficiency are required. As draw resistance and filtration efficiency are closely related, it is difficult to adjust these parameters independently over a wide range.
Thus, the industry is interested in having available a filter material that allows the manufacture of segments for which draw resistance and filtration efficiency can be modified independently of each other over a wide range.
The objective of the invention is to provide a segment of a smoking article or for a smoking article for which the draw resistance and filtration efficiency can be adjusted simply and reliably essentially independently of each other and which in this respect is superior to conventional segments. A further objective of the invention is to provide a readily biodegradable segment for smoking articles.
This objective is achieved by a segment according to claim 1, a filter rod according to claim 35 and a smoking article according to claim 39. Advantageous embodiments are provided in the dependent claims.
The inventors have found that the objective can be achieved by a segment of a smoking article that comprises a wrapper material and a filter material, wherein the wrapper material wraps the filter material and the filter material is formed to at least 10% and at most 100% of its mass from a calendered fibrous web, and wherein at least 50% and at most 100% of the mass of the calendered fibrous web is formed by organic polymer fibers and wherein the calendered fibrous web has a compression factor of at least 0.45 and at most 0.85, wherein the compression factor is the ratio between the density of the calendered fibrous web and the volume weighted density of the components of the calendered fibrous web.
According to the prior art, the skilled person would like the filter material in a segment of a smoking article to have a porous structure with low density, in order to offer a sufficient surface area to the aerosol flowing through the segment, so that components of the aerosol can be filtered efficiently. In this regard, each filter material is separately investigated as to how draw resistance and filtration efficiency are related, and for the desired parameters, the type and mass of the filter material in the segment are defined. In this regard, aside from the draw resistance and the filtration efficiency, other aspects are also important, in particular the hardness of the segment, which is primarily determined by the mass of the filter material and in part by the wrapper material. In particular, it is difficult to obtain a low draw resistance and a low filtration efficiency at sufficient hardness. Also, it is difficult for a segment to achieve a low draw resistance and a high filtration efficiency or vice versa, a high draw resistance and a low filtration efficiency. However, for smoking articles, in particular heated tobacco products, there is a high demand for such segments.
The inventors have surprisingly found that a calendered fibrous web as component of the segment in a smoking article can achieve this objective. According to the prior art, the skilled person would not consider a calendered fibrous web for use as filter material in a segment of this kind, because it would be assumed that the calendering compresses the fibrous web, smooths and seals the surface and generates a non-porous structure, which has a very low filtration effect and makes such a fibrous web unsuitable for segments in smoking articles. The inventors, however, have found that, contrary to expectations, calendered fibrous webs as filter material for such segments are suitable, if they are calendered such that the compression factor is in the interval according to the invention. In this narrow range for the compression factor, a surprising effect has been found in that the draw resistance of a segment manufactured therefrom is comparatively low, but that the filtration efficiency is still in the medium range and in particular that the filtration efficiency is practically constant and independent of the draw resistance and the mass of the calendered fibrous web in the segment. A calendered fibrous web with the compression factor according to the invention thus allows the draw resistance or the hardness of the segment to be adjusted without changing the filtration efficiency. This is not possible to the same extent with available filter materials of the prior art.
The compression factor is the ratio of the density of the calendered fibrous web to the volume-weighted density of the components of the calendered fibrous web. The ratio essentially describes how intensively the calendered fibrous web is compressed. A compression factor of 1 means maximum compression so that there is no pore volume left in the calendered fibrous web, while at lower compression factors, some pore volume remains in the calendered fibrous web.
If the fibrous web consists of i=1,2,3, . . . , N components with densities ρi and the masses per unit area mi, then the volume-weighted density ρo of the components of the calendered fibrous web is calculated by
The basis weight can be determined in accordance with ISO 536:2019 and the thickness in accordance with ISO 534:2011. The compression factor C is then the ratio of the density of the calendered fibrous web ρe and to the density of the components of the calendered fibrous web ρo, and thus
In order to achieve the effect according to the invention, the compression factor has to be at least 0.45 and at most 0.85. For the calculation of the compression factor C, it is not necessary to include the entirety of all of the components. It suffices if the components used for the calculation in total make up at least 90% of the mass of the calendered fibrous web. Exemplary calculations of the compression factor are provided further below.
The inventors have so far not found a theory as to why, contrary to expectations, a calendered fibrous web has a filtration efficiency in the medium range and why, in the range of the compression factor according to the invention, the draw resistance is uncoupled from the filtration efficiency. As explained further below, however, it can be shown by experiments that the compression factor of the calendered fibrous web is the essential criterion in achieving the inventive effect. Also, it has to be assumed that the porous structure and the surface of the calendered fibrous web generated by calendering to the compression factor according to the invention is of importance.
The segment according to the invention comprises a filter material, wherein at least 10% and at most 100% of the mass of the filter material are formed by a calendered fibrous web. Because of the calendered fibrous web, the draw resistance and filtration efficiency can be adjusted independently of each other. As an example, the proportion of the calendered fibrous web in the filter material can be increased in order to increase the draw resistance but to leave the filtration efficiency unchanged. Thus, preferably at least 20% and at most 90% of the mass of the filter material are formed by the calendered fibrous web and particularly preferably, at least 25% and at most 75% of the mass of the filter material. In some embodiments, the proportion of the calendered fibrous web in the filter material is rather high and is at least 30% and at most 100% of the mass of the filter material.
The compression factor of the calendered fibrous web is essential for the segment according to the invention because, according to the findings of the inventors, the draw resistance and the filtration efficiency are uncoupled in only a certain range for the compression factor. Preferably, the compression factor of the calendered fibrous web is at least 0.50 and at most 0.80 and particularly preferably at least 0.55 and at most 0.75. Within the range according to the invention, the investigations of the inventors show that the draw resistance and the filtration efficiency are uncoupled from each other and in the preferred intervals of the compression factor, the calendering process can be carried out particularly efficiently.
In the segment according to the invention, the fibrous web, which forms at least a portion of the filter material, is calendered. This can mean that during manufacture, the fibrous web has run through at least one nip in which a mechanical pressure acts on the fibrous web, whereupon it is compressed and smoothed. In this regard, for example, the mechanical pressure and the number of nips can be selected such that the compression factor of the calendered fibrous web is in the range according to the invention. In order to support the calendering process, the rolls forming the nip can be heated and/or the moisture content of the fibrous web can be adjusted before calendering. In order to manufacture the calendered fibrous web for the segment according to the invention, it is important that the moisture content of the fibrous web during calendering is increased compared to the equilibrium state of a dry fibrous web in order to achieve the compression factor according to the invention. In addition, the skilled person is capable of adjusting further parameters of the calendering process based on the properties of the fibrous web so that the desired compression factor is achieved.
This process of calendering has to be differentiated here from other processes such as, for example, those in a size press or a coating device, in which substances are applied to the surface of a fibrous web. In this regard, the fibrous web can indeed also run through a nip, but a high pressure is not exerted on the fibrous web, so that the fibrous web is not or is only slightly compressed and the compression factor according to the invention is not achieved.
The calendered fibrous web comprises organic polymer fibers. Organic polymer fibers are fibers that consist of polymers the main chain of which contains carbon atoms. Such polymer fibers are in principle suitable for forming and calendering a fibrous web so that the invention can be realized.
Inorganic fibers such as glass fibers, metal fibers or mineral fibers and fibers from inorganic polymers such as polysiloxanes, are not according to the invention.
The biodegradability of the calendered fibrous web can be improved by the selection of the polymer fibers, or even made possible by it. Because smoking articles are often disposed of in the environment after use, it is important that the segments of which the smoking article consists are readily biodegradable.
Preferably, the organic polymer fibers are therefore fibers produced from biopolymers. Biopolymers are polymers that are synthesized by living organisms or are chemically identical to polymers synthesized by living organisms. Modified polymers, synthesized by living organisms or synthesizable by living organisms, are also biopolymers within the scope of this invention. As an example, synthetic polymers such as polyethylene or polypropylene are not biopolymers and are thus less preferred but still according to the invention. In this regard, preferably, at least 80% by weight, particularly preferably at least 90% by weight and ideally all of the organic polymer fibers are produced from biopolymers.
In order to further optimize the biodegradability, in a particularly preferred embodiment, the organic polymer fibers are fibers from cellulose-based polymers. Examples of fibers from cellulose-based polymers are pulp fibers, fibers from regenerated cellulose and fibers from cellulose acetate. Less preferred, but according to the invention, are fibers from polylactides, which are a biopolymer, but not a cellulose-based biopolymer and biodegrade less readily than, for example, pulp fibers. Also less preferred are fibers from cellulose acetate, which are a cellulose-based biopolymer, but biodegrade even less readily than fibers produced from polylactides.
In order to achieve the best biodegradability of the segment according to the invention, in a particularly preferred embodiment, said fibers produced from biopolymers are pulp fibers, fibers from regenerated cellulose or a mixture thereof.
In particular, at least 80% by weight and preferably at least 90% by weight and in particular all of said organic polymer fibers are pulp fibers sourced from coniferous trees, deciduous trees or other plants such as hemp, flax, jute, ramie, kenaf, kapok, coconut, abacá, sisal, bamboo, cotton or from esparto grass, or a mixture of pulp fibers from two or more of these trees or plants. In other words, the pulp fibers can be sourced from exactly one of the aforementioned sources or can be a mixture of pulp fibers that are sourced from two or more of said sources. Apart from the optimal biodegradability, these fibers are also available in uniform qualities and high quantities.
The proportion of organic polymer fibers in the calendered fibrous web can vary. According to the invention, it is at least 50% and at most 100% of the mass of the calendered fibrous web, in order to provide the fibrous web with good strength for further processing. Preferably, the proportion of organic polymer fibers in the mass of the calendered fibrous web is higher and is at least 60% and at most 100% and particularly preferably at least 70% and at most 95%. A high proportion of organic polymer fibers allows the fibrous web to be calendered with less pressure in order to achieve the compression factor according to the invention.
For good biodegradability, it is preferred that the calendered fibrous web contains less than 40%, particularly preferably less than 30% and in particular less than 20% of fibers from cellulose acetate, wherein the percentages relate to the mass of the calendered fibrous web. In particular, the calendered fibrous web is free from fibers of cellulose acetate.
The calendered fibrous web can contain filler material. Filler material provides the calendered fibrous web with a porous structure and is generally less compressible, so that the calendering of the fibrous web requires a higher pressure in order to achieve the desired compression factor. Preferably, the proportion of filler material is therefore at least 0% and at most 50% of the mass of the calendered fibrous web, particularly preferably, it is at least 0% and at most 30% and more particularly preferably at least 0% and at most 5%, each with respect to the mass of the calendered fibrous web. The filler material can be useful to increase the brightness of the fibrous web. This can be of importance if the segment manufactured therefrom is located at the end of the smoking article and its cross sectional surface is visible. The filler material can also be used because it is cheaper than organic polymer fibers. For these reasons, a filler content of at least 5% and at most 35% with respect to the mass of the calendered fibrous web is also preferred as an alternative.
Preferably, the filler material is selected from the group consisting of calcium carbonate, magnesium carbonate, titanium dioxide, magnesium oxide, aluminum hydroxide, magnesium silicate, aluminum silicate, kaolin, talcum and bentonite, or can be formed by a mixture of two or more of these types of filler materials.
The calendered fibrous web can contain additives to provide the calendered fibrous web with special properties. These additives can, for example, influence the strength in the dry or wet state, the water absorption, the filtration efficiency in total or for particular substances. The proportion of additives in the calendered fibrous web is preferably at least 0% and at most 10% of the mass of the calendered fibrous web, particularly preferably at least 1% and at most 9% of the mass of the calendered fibrous web.
Preferably, the additives are selected from the group consisting of sizing agents, alkylketene dimers (AKD), alkenyl succinic acid anhydrides (ASA), fatty acids, starch, starch derivatives, carboxy methyl cellulose, alginates, chitosan, wet strength agents, citrates, trisodium citrate, tripotassium citrate, malates, tartrates, acetates, nitrates, succinates, fumarates, gluconates, glycolates, lactates, oxalates, salicylates, α-hydroxy caprylates, phosphates, polyphosphates, chlorides, hydrogen carbonates, triacetin, propylene glycol, ethylene glycol, sorbitol, glycerol, polyethylene glycol, polypropylene glycol, polyvinyl alcohol, triethyl citrate, catalysts, activated carbon, flavors, encapsulated flavors or mixtures thereof.
The basis weight of the calendered fibrous web is preferably at least 15 g/m2 and at most 44 g/m2, preferably at least 20 g/m2 and at most 40 g/m2 and particularly preferably at least 23 g/m2 and at most 38 g/m2, in particular at least 31 g/m2 and at most 37 g/m2. This basis weight is advantageous in order to facilitate calendering of the fibrous web for further processing of the calendered fibrous web into a segment of a smoking article and it can provide the calendered fibrous web with a good strength. The values refer to a basis weight measured in accordance with ISO 536:2019.
The thickness of the calendered fibrous web is preferably at least 15 μm and at most 55 μm, and particularly preferably at least 20 μm and at most 50 μm and in particular at least 30 μm and at most 37 μm. The thickness can be measured in accordance with ISO 534:2011 and refers to the thickness of the fibrous web after calendering.
The mechanical properties of the calendered fibrous web are important for processing into a segment of a smoking article. The tensile strength per unit width of the calendered fibrous web, measured in accordance with ISO 1924-2:2008, is preferably at least 6 N/15 mm and at most 70 N/15 mm, particularly preferably at least 8 N/15 mm and at most 60 N/15 mm.
The elongation at break of the calendered fibrous web is of importance because, during processing of the fibrous web into a segment of a smoking article, the fibrous web is often crimped and thereby a particularly high elongation at break is beneficial. The elongation at break of the calendered fibrous web, measured in accordance with ISO 1924-2:2008, is therefore preferably at least 0.8% and at most 3.0% and particularly preferably at least 1.0% and at most 2.5%.
Tensile strength and elongation at break can depend on the direction in which the sample for the measurement is taken from the filter material. However, because of calendering, this dependence on direction is low. The said features of the calendered fibrous web are each present if the tensile strength or the elongation at break lies in said preferred or particularly preferred ranges in at least one direction.
The inventors have also found that a coating can improve the effect of the calendering and an even better uncoupling of draw resistance and filtration efficiency can be achieved, in particular if the basis weight of the calendered fibrous web is low. A coating also allows the surface of the fibrous web to be altered and, for example, a selective filtration of particular substances of the aerosol to be obtained.
In this regard, the coating can be in applied in the form of a composition which comprises the coating material and a solvent, wherein the solvent is removed after application, for example by drying. The coating consists of only those components of the composition which remain on the calendered fibrous web.
In a preferred embodiment of the segment, the calendered fibrous web is coated on at least one side, wherein the coating on at least one side covers at least 20% and at most 100% of the area of this side of the calendered fibrous web and wherein the coating comprises a material that is selected from the group consisting of sizing agents, alkylketene dimers (AKD), alkenyl succinic acid anhydrides (ASA), fatty acids, starch, starch derivatives, carboxy methyl cellulose, alginates, chitosan, wet strength agents, citrates, trisodium citrate, tripotassium citrate, malates, tartrates, acetates, nitrates, succinates, fumarates, gluconates, glycolates, lactates, oxalates, salicylates, α-hydroxy caprylates, phosphates, polyphosphates, chlorides, hydrogen carbonates, triacetin, propylene glycol, ethylene glycol, sorbitol, glycerol, polyethylene glycol, polypropylene glycol, polyvinyl alcohol, triethyl citrate, catalysts, activated carbon, flavors and encapsulated flavors, or wherein the coating comprises a mixture of two or more of these materials.
In a particularly preferred embodiment, the coating comprises a material that is selected from the group consisting of starch, starch derivatives, cellulose derivatives and mixtures thereof. More particularly preferably, the coating comprises a material that is selected from the group consisting of starch, starch derivatives, cellulose derivatives and mixtures thereof (i.e. the material is a mixture of two or more of these substances), and the proportion of this material in the coating is at least 20% and at most 100%, preferably at least 50% and at most 100%, particularly preferably at least 70% and at most 98% and in particular at least 80% and at most 95%, each with respect to the mass of the coating applied to the calendered fibrous web.
In a particularly preferred embodiment, only one side of the calendered fibrous web is coated and the coating covers at least 50% and at most 100% of the area of the coated side of the calendered fibrous web, and more particularly preferably at least 90% and at most 100% of the area of the coated side of the calendered fibrous web, in particular if, for example, a full-surface coating of the fibrous web has to be avoided for technical reasons, at least 80% and at most 95% of the area of the coated side of the calendered fibrous web. Such technical reasons can be that a portion of the calendered fibrous web is to remain uncoated in order to still be able to determine properties of the fibrous web without coating on the finished fibrous web.
In a particularly preferred embodiment, the calendered fibrous web is coated on both sides and the coating covers at least 20% and at most 100% of the area of each of both sides of the calendered fibrous web and more particularly preferably at least 50% and at most 100% of the area of each of both sides of the calendered fibrous web in particular at least 90% and at most 100% of the area of each of both sides of the calendered fibrous web o, if, for example, a full-surface coating of the fibrous web has to be avoided for technical reasons, at least 80% and at most 95% of the area of each of both sides of the calendered fibrous web.
The amount of coating material that is applied to one side or both sides of the calendered fibrous web, is particularly preferably at least 0.5 g/m2 and at most 5.0 g/m2, more particularly preferably at least 0.7 g/m2 and at most 4.0 g/m2, wherein each amount in g/m2 is only with respect to the area to which the coating material is actually applied.
In a preferred embodiment of the segment, the calendered fibrous web is coated on at least one side, wherein the coating on at least one side covers at least 20% and at most 100% of the area of this side of the calendered fibrous web and the basis weight of the calendered fibrous web including the coating is at least 20 g/m2 and at most 35 g/m2. In a particularly preferred embodiment of this segment, the coating comprises a material which is selected from the group consisting of starch, starch derivatives, cellulose derivatives and mixtures of two or more thereof.
The calendered fibrous web is preferably a calendered paper or a calendered nonwoven. Such preferred calendered fibrous webs can be manufactured by processes which are known in the art.
The segment according to the invention comprises a filter material, wherein at least 10% of the mass of the filter material is formed by the calendered fibrous web. The filter material can be entirely formed by the calendered fibrous web. The purpose of the calendered fibrous web is primarily to uncouple the draw resistance of the segment from the filtration efficiency. In order to achieve this purpose, at least 10% of the mass of the filter material has to be formed by the calendered fibrous web. However, it is advantageous to combine the calendered fibrous web with further filtration material.
In a preferred embodiment, the filter material of the segment according to the invention comprises a calendered fibrous web and a further filtration material, wherein the further filtration material is preferably selected from the group consisting of filter papers, nonwovens or tows and combinations thereof.
Particularly preferably, the further filtration material is selected from the group consisting of filter papers, cellulose-based nonwovens, hydroentangled nonwovens, tows comprising cellulose acetate, tows comprising regenerated cellulose and combinations of two or more of these. These further filtration materials allow the filtration efficiency of the segment to be adjusted particularly well.
In a particularly preferred embodiment, the further filtration material is a filter paper, a cellulose-based nonwoven, a hydroentangled nonwoven or a combination of two or more thereof. These further filtration materials allow for good biodegradability and can therefore be combined with the calendered fibrous web in a particularly advantageous manner. In a further embodiment of this particularly preferred embodiment, the further filtration material is web-shaped and is laminated to the calendered fibrous web.
Preferably, at least 10% and at most 90% and particularly preferably at least 20% and at most 70% of the mass of the filter material is formed by the further filtration material.
In a particularly preferred embodiment that combines the effect of the calendered fibrous web on the draw resistance and the filtration efficiency with the biodegradability of the segment in a particularly beneficial manner, the segment of a smoking article comprises a wrapper material and a filter material, wherein the wrapper material wraps the filter material and at least 70% and at most 100% of the mass of the filter material is formed by a calendered fibrous web and wherein at least 50% and at most 100% of the mass of the calendered fibrous web is formed by organic polymer fibers and wherein the calendered fibrous web has a compression factor of at least 0.45 and at most 0.85 and at most 30% and in particular at most 20% of the mass of the filter material is formed by cellulose acetate.
The segment according to the invention for a smoking article comprises the filter material and a wrapper material, wherein the wrapper material wraps the filter material and is preferably a paper or a film.
In this regard, the wrapper material has to be strictly differentiated from the calendered fibrous web, which is a component of the filter material. The wrapper material of a segment for a smoking article has completely different requirements, such as processability by gluing, air permeability, color, suitability for perforation and, at times, printability, while the filtration properties and the effect on the draw resistance are of no importance.
The wrapper material of the segment according to the invention preferably has a basis weight of at least 20 g/m2 and at most 150 g/m2, particularly preferably at least 30 g/m2 and at most 130 g/m2. A wrapper with this preferred or particularly preferred basis weight in combination with the filter material provides the segment according to the invention wrapped thereby with a particularly advantageous hardness. The smoker cannot accidentally compress the segment located in the smoking article thereby.
In a preferred embodiment, of the segment according to the invention, the segment is cylindrical with an approximately circular or oval outer boundary of the cross sectional surface with a nominal diameter of this boundary of at least 3 mm and at most 10 mm, particularly preferably at least 4 mm and at most 9 mm and more particularly preferably at least 5 mm and at most 8 mm. These nominal diameters are suitable for using the segment according to the invention in smoking articles. The nominal diameter can be determined in accordance with ISO 2971:2013.
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 in particular at least 10 mm and at most 28 mm.
The draw resistance of the segment determines, inter alia, which pressure difference the smoker has to apply during consumption of the smoking article in order to generate a specific volumetric flow through the smoking article, and it therefore substantially influences the acceptance of the smoking article for the smoker. The draw resistance of the segment can be measured in accordance with ISO 6565:2015 and is given in mm water gauge (mmWG). To a very good approximation, the draw resistance of the segment is proportional to the length of the segment, so that the measurement of the draw resistance can also be carried out on rods that differ from the segment solely in respect of length. The draw resistance of the segment can easily be calculated therefrom.
The draw resistance of the segment per unit length of the segment is preferably at least 0.05 mmWG/mm and at most 12.0 mmWG/mm, particularly preferably at least 0.1 mmWG/mm and at most 10.0 mmWG/mm and more particularly preferably at least 0.1 mmWG/mm and at most 4.0 mmWG/mm.
Typically, the segment has an essentially cylindrical shape with an approximately circular or oval outer boundary of the cross sectional surface and can have one or more cavities in its interior, for example to accommodate activated carbon particles or breakable capsules with flavors. The cavities can also be formed as one or more elongated tubes that run at least approximately parallel to the longitudinal axis of the segment and are located entirely in the segment or terminate at one or both end surfaces of the segment. Such cavities can also influence the filtration efficiency and the draw resistance. The direction of the longitudinal axis coincides with the flow direction of the aerosol in the smoking article, when the smoker puffs on the smoking article during use of the smoking article.
The segment according to the invention can also contain an aerosol-forming material, in particular a tobacco material.
The manufacture of a segment according to the invention can be carried out according to processes known in the art.
The filter rod according to the invention is cylindrical with an approximately circular or oval outer boundary of the cross sectional surface, has a length of at least 40 mm and at most 200 mm and comprises at least one segment according to the invention.
Preferably, the filter rod comprises at least one segment according to the invention and at least one further segment, which comprises a filter material, wherein the segments are arranged one after the other in the longitudinal direction of the filter rod. Particularly preferably, the filter material of the further segment comprises cellulose acetate.
Preferably, the filter rod comprises a plurality of segments according to the invention and a plurality of further segments which are identical to each other, wherein the number of the segments according to the invention is equal to the number of further segments which are identical to each other in the filter rod and in the longitudinal direction of the filter rod a segment according to the invention and a further segment are arranged in alternation one after the other. In a particularly preferred embodiment of this filter rod, the number of segments according to the invention and the number of further segments which are identical to each other is respectively two, three, four, five or six.
Such a filter rod, called a “dual filter”, allows the advantageous properties of the segment according to the invention to be combined with a further segment that, apart from its filtration properties, also provides the mouth end of a smoking article manufactured from the filter rod with a good optical appearance.
Preferably, the filter rod is cylindrical with an approximately circular or oval outer boundary of the cross sectional surface and with a nominal diameter of at least 3 mm and at most 10 mm, particularly preferably at least 4 mm and at most 9 mm and in particular at least 5 mm and at most 8 mm. The nominal diameter can be determined in accordance with ISO 2971:2013.
The manufacture of a filter rod according to the invention can be carried out according to processes known in the art.
The smoking article according to the invention comprises at least two segments, wherein one of the segments is a segment according to one of the aforementioned embodiments and at least one of the segments contains an aerosol-forming material.
The inventors have found that the segment according to the invention can be used particularly advantageously in smoking articles that comprise at least three segments, wherein a first segment can contain an aerosol-forming material, a second segment can be a segment according to one of the aforementioned embodiments and a third segment can serve for the filtration, and wherein the second segment is arranged between the first and the third segment.
With the combination of the second segment with the third segment, an even wider range of filtration efficiencies and draw resistances can be covered and the filtration efficiency can be adapted even better to that of conventional filters, for example from cellulose acetate. In this regard, the desired filtration efficiency results from the combination of the second segment and the third segment and the draw resistance can then be adjusted by the amount of the calendered fibrous web in the second segment without substantially changing the filtration efficiency. Such a smoking article can, for example, be manufactured from the filter rod designated further above as “dual filter”.
In a preferred embodiment, the smoking article thus comprises at least three segments, wherein a first segment contains an aerosol-forming material, a second segment is a segment according to one of the aforementioned embodiments and wherein the second segment is arranged between the first and the third segment. In a particularly preferred embodiment of this smoking article, the draw resistance of the third segment is higher than that of the second segment. In a particularly preferred embodiment of this smoking article, the ratio of the length of the second segment to the length of the third segment is at least 1:2 and at most 5:1, particularly preferably at least 1:1 and at most 3:1. The length of the segments influences the draw resistance, so that the draw resistance can be even better adjusted by selection of the length.
In a particularly preferred embodiment of this smoking article, the third segment comprises a filter paper, a cellulose-based nonwoven, a hydroentangled nonwoven, a tow comprising cellulose acetate or a tow comprising regenerated cellulose.
In a preferred embodiment, the smoking article is a filter cigarette and the aerosol-forming material comprises tobacco.
The segment according to the invention is particularly well suited to smoking articles which heat the aerosol-forming material but do not burn it during their intended use. Such smoking articles consist of several, typically two to four, segments, wherein one segment contains the aerosol-forming material and the other segments can serve for transfer, cooling or filtering of the aerosol. These segments require substantially different draw resistances and filtration efficiencies, so that for such smoking articles, there is a particular need to adjust draw resistance and filtration efficiency of a segment simply and reliably over a wide range.
In a preferred embodiment, the smoking article is therefore a smoking article which just heats the aerosol-forming material but does not burn it during the intended use and the aerosol-forming material comprises a material selected from the group consisting of tobacco, reconstituted tobacco, nicotine, glycerol, propylene glycol and flavors or a mixture of two or more of these materials, and particularly preferably, the aerosol-forming material is heated electrically. The aerosol-forming material can thereby also be present as a gel or in liquid form and can preferably be contained in a container in a segment of the smoking article.
The segment according to the invention as well as the smoking article according to the invention can be manufactured according to processes known in the art.
Some preferred embodiments of segments according to the invention will be described below and compared with examples not according to the invention.
In the context of this invention, an exemplary fibrous web of a segment according to the invention with a basis weight of 32 g/m2, for which the mass per unit area consists of m1=27.0 g/m2 pulp fibers with a density ρ1=1.5 g/cm3, of m2=3.2 g/m2 calcium carbonate particles with a density ρ2=2.7 g/cm3, and the remaining mass of further additives, has a volume-weighted density ρo of the components of
In this regard, the further additives were neglected, because their influence on the density is small.
If a calendered fibrous web with a thickness of d=28 μm is manufactured from these components, the compression factor C is
In the context of this invention, a further exemplary fibrous web of a segment according to the invention with a basis weight of 25 g/m2, for which the mass per unit area consists of m1=22.5 g/m2 polyethylene fibers with a density ρ1=0.95 g/cm3 and of m2=2.0 g/m2 titanium dioxide particles with density ρ2=4.2 g/cm3 and the remaining mass made up of further additives, has a density ρo of the components of
In this regard, the further additives were neglected, because their influence on the density is small.
If a calendered fibrous web with a thickness of d=30 μm is manufactured from these components, the compression factor C is
The densities of the components of the calendered fibrous web are in general known in the art. By way of example. Table 1 shows some typical values.
A mixture of pulp fibers consisting of 80% pulp fibers from spruce and pine and 20% pulp fibers from birch was used for the manufacture of the calendered fibrous web. The pulp fibers from spruce and pine were refined to a degree of refining of 67°SR, measured in accordance with ISO 5267-1:1999. Starch was added to the fibrous web so that about 95% of its mass consisted of pulp fibers and 5% of starch. The fibrous web was manufactured on a conventional paper machine and calendered at elevated moisture content of the fibrous web in a calendar integrated into the paper machine.
The density of the components, neglecting the starch, was thus ρo=1.5 g/m3.
The basis weight was 35 g/m2 and the thickness 33 μm, thus the compression factor is
The tensile strength and the elongation at break of the calendered fibrous web A were measured according to ISO 1924-2:2008, wherein for the tensile strength in the machine direction a value of 51.6 N/15 mm and for the elongation at break in the machine direction, a value of 1.1% was obtained.
The fibrous web was also calendered more and less intensively so that other thicknesses and compression factors resulted, as are further shown in Table 3.
Fibers from regenerated cellulose were refined to a degree of refining of 73° SR, measured in accordance with ISO 5267-1:1999. From the fibers, a fibrous web was formed on a paper machine using suitable process aids, so that about 99% of the mass of the fibrous web consisted of fibers of regenerated cellulose. The fibrous web was calendered at elevated moisture content of the fibrous web in a calender integrated into the paper machine.
The density of the components was thus ρo=1.5 g/m3.
The basis weight was 42 g/m2 and the thickness 38 μm, thus the compression factor is
The tensile strength and the elongation at break of the calendered fibrous web B were measured according to ISO 1924-2:2008, wherein for the tensile strength in the machine direction a value of 61.7 N/15 mm and for the elongation at break in the machine direction, a value of 1.0% was obtained.
Cylindrical filter rods with a length of 108 mm and a diameter of about 7.1 mm were manufactured from each of the calendered fibrous webs A and B, wherein the filter material of the filter rods was entirely formed by the calendered fibrous web and was wrapped with a suitable wrapper material with a basis weight of 78 g/m2. The width of the fibrous web that was used for manufacturing the filter rods varied between 60 mm and 242 mm, whereupon different amounts of filter material were present in the filter rod, in order to vary the draw resistance. The length of the calendered fibrous web that was used for the manufacture of the filter rods was about 108 mm.
Filter cigarettes were manufactured from the 108 mm long filter rods, wherein the filter rods, cut to segments with a length of 18 mm, served as a filter segment in the filter cigarette. The tobacco blend of the filter cigarette was an American Blend and within the usual production tolerances, the filter cigarettes differed only in respect of the filter segment.
The filtration efficiency for nicotine was measured as a characteristic parameter for the filtration efficiency. The filter cigarettes were smoked according to a method specified in ISO 3308:2012 and the mass of nicotine (m) exiting from the mouth end as well as the mass of nicotine contained in the filter segment (mFilter) were determined and by using
m
Filter/(m+mFilter)
Table 2 shows the width of the fibrous web (W), the draw resistance (PD), and filtration efficiency (FE) used for nicotine each for a 18 mm long segment, manufactured from the calendered fibrous webs A and B.
These results were compared with filters produced from paper, which was very similar to calendered fibrous web A with respect to composition and basis weight but not calendered, and from cellulose acetate. The results are shown in
In order to determine in which range of the compression factor for the calendered fibrous web the draw resistance and the filtration efficiency are essentially uncoupled, a fibrous web with a composition of the fibrous web A was calendered using different settings of the calender, so that different thicknesses and densities of the calendered fibrous web resulted. Filter rods with a length of 108 mm were respectively manufactured from a 40 mm and a 159 mm wide calendered fibrous web and cut into 18 mm long segments. The draw resistance of the segments, Δp40, for the 40 mm wide fibrous web and Δp159 for the 159 mm wide fibrous web, and the filtration efficiency for nicotine of the segments, F40 for the 40 mm wide fibrous web and F159 for the 159 mm wide fibrous web, were determined as described before and a mean rate of change of the filtration efficiency for nicotine was determined relative to the change in draw resistance therefrom by
The results are shown in Table 3 wherein, for comparison, a mean rate of change of the filtration efficiency for nicotine determined in an analogous manner is also provided for the segment from the non-calendered filter paper (Y), ρo=1.5 g/cm3, and from cellulose acetate (Z) based on the data in
It can be seen from Table 3 that in a range of the compression factor of the calendered fibrous web from about 0.45 to about 0.85, the draw resistance and the filtration efficiency for nicotine are essentially uncoupled. However, also at a compression factor of greater than 0.85, the mean rate of change of the filtration efficiency (ΔF/AP) is still small, but the pressure required for the calendering is already very high, so that it is beneficial not to choose the compression factor greater than 0.85.
Furthermore, in relation to Table 2 the data for the calendered fibrous web B show that an uncoupling of draw resistance and filtration efficiency is essentially independent of the composition of the calendered fibrous web. The range of the compression factor according to the invention is thus valid independently of the composition of the fibrous web.
A fibrous web with a basis weight of 23 g/m2 was manufactured from a mixture of pulp fibers consisting of 45% pulp fibers from spruce and pine and 55% pulp fibers from eucalyptus. The pulp fibers from spruce and pine were refined to a degree of refining of 94° SR, measured in accordance with ISO 5267-1:1999. The fibrous web was manufactured on a conventional paper machine and then coated with starch over the entire surface on both sides on a separate coating unit and calendered at elevated moisture content of the fibrous web on a further device in order to obtain the calendered fibrous web C.
The amount of starch applied to both sides by coating taken together was about 1.5 g/m2, i.e. 6.12% of the mass of the calendered fibrous web, so that a basis weight of 24.5 g/m2 resulted.
The density of the components, neglecting the starch was thus ρo=1.5 g/cm3.
From a thickness of 20 μm, the resulting compression factor is
The tensile strength and the elongation at break of the calendered fibrous web C were measured in accordance with ISO 1924-2:2008, wherein for the tensile strength in the machine direction, a value of 29 N/15 mm and for the elongation at break in the machine direction a value of 2.0% was obtained.
A calendered fibrous web D was manufactured in the same manner but without the coating.
Filter rods with a length of 108 mm were manufactured from the calendered fibrous webs, wherein the calendered fibrous web C was used with a width of 120 mm and 180 mm and the calendered fibrous web D was used with a width of 120 mm and 180 mm, in order to manufacture four different segments. The length of the calendered fibrous web approximately agreed in all cases with the length of the filter rods of 108 mm. The filter rods were wrapped with a wrapper material with a basis weight of 78 g/m2. The filtration efficiency for nicotine was determined in the same manner as for the fibrous webs A and B and in Table 4, the width (W) of the calendered fibrous web, the draw resistance (PD) of an 18 mm long segment and the filtration efficiency (FE) for nicotine are shown.
While for the segments according to the invention manufactured from the calendered fibrous web D, the filtration efficiency still somewhat depends on the draw resistance and changes with a rate of change of (37.4-35.9)/(6.7-2.9)=0.39%/mmWG, this rate of change for the segments according to the invention manufactured from the coated and calendered fibrous web C is only (29.3-30.8)/(22.5-5.9)=0.09%/mmWG. This shows that due to the coating, the draw resistance and the filtration efficiency can be uncoupled even better.
A comparison of these rates of change of segments from the calendered fibrous webs A and B with a basis weight of 35 g/m2 and 42 g/m2, respectively, with segments from the calendered fibrous webs C and D with a basis weight of 24.5 g/m2 and 23 g/m2, respectively, also shows that the positive effect of the calendering is lower at a low basis weight of the calendered fibrous web and this effect can be compensated for well by a coating.
Combination with Filtration Material
Starting from an 18 mm long filter segment produced from cellulose acetate with a draw resistance of about 30 mmWG and a filtration efficiency for nicotine of 22.4%, the mass of cellulose acetate was reduced and a 79 mm wide, calendered fibrous web A was added to the filter material. The 18 mm long segment then had a draw resistance of about 15 mmWG and a filtration efficiency of 22.8%. This shows that with the segment according to the invention it is possible to reduce the draw resistance to about a half and keep the filtration efficiency for nicotine approximately constant. If such a reduction of the draw resistance were to be achieved without using the calendered fibrous web A, the filtration efficiency for nicotine would be too low and the hardness of the filter segment would be insufficient.
The results therefore show that the segment according to the invention can offer great advantages with respect to the adjustment of the draw resistance and the filtration efficiency under consideration of the hardness of the segment and that also, further improvements can be achieved with respect to the biodegradability.
Smoking Article from Three Segments
A filter cigarette F according to the invention with a length of 83 mm and a diameter of 7.8 mm was manufactured from three segments, wherein the first segment contained an American Blend as tobacco blend, the second segment was a segment according to the invention from the calendered fibrous web C and the third segment contained a filter paper. The second segment was arranged between the first and the third segment and the third segment formed the mouth end of the filter cigarette.
The second segment had a length of 18 mm with a draw resistance of 22 mmWG, while the third segment was 9 mm long and had a draw resistance of 46 mmWG.
The filter paper in the third segment was a paper essentially consisting of 100% pulp fibers with a basis weight of 35 g/m2 and a thickness of 88 μm.
As a comparative example not according to the invention, a filter cigarette X was manufactured with 83 mm, a diameter of 7.8 mm and an American Blend tobacco blend and a 27 mm long filter segment produced from cellulose acetate. The filter segment had a draw resistance of 84 mmWG.
The filter cigarette F according to the invention and the filter cigarette X not according to the invention serving as comparative example contained the same mass of tobacco and were ventilated by a perforation in the region of the filter, wherein the degree of ventilation was adjusted such that both filter cigarettes had an open draw resistance of about 100 mmWG.
Both filter cigarettes were smoked according to the standardized methods in ISO 3308 and ISO 4387 and the total particulate matter (TPM), nicotine and carbon monoxide (CO), as well as the puff count (PC) were determined.
The values shown in Table 5 were obtained.
It can be seen from these data that by the combination of the segment according to the invention with a further segment serving for filtration, the smoke yields can be adjusted very well to an otherwise identical filter cigarette with a filter from cellulose acetate. Apart from the flexibility when adjusting the draw resistance and the filtration efficiency, substantial ecological advantages are also generated, because poorly biodegradable cellulose acetate can be avoided.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2022 102 066.5 | Jan 2022 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/051409 | 1/20/2023 | WO |
