EP3700366B1 - Biodegradable segment of a smoking product - Google Patents

Description

FIELD OF THE INVENTION

The invention relates to a segment of a smoking article, in particular a segment for cooling or filtering the aerosol flowing in the smoking article, which is more biodegradable than segments known from the prior art and which has a favorable combination of properties in terms of draw resistance and filtration efficiency.

BACKGROUND AND PRIOR ART

Smoking articles are typically rod-shaped articles consisting of at least two rod-shaped segments arranged one after the other. One segment contains a material capable of forming an aerosol when heated, and at least one other segment serves to influence 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 a further segment is designed as a filter and is used to filter the aerosol. The aerosol is generated by burning the aerosol-forming material, and the filter primarily serves to filter the aerosol and to provide the filter cigarette with a defined draw resistance. However, the smoking article can also be a so-called heated tobacco product in which the aerosol-forming material is only heated but not burned. This reduces the number and amount of harmful substances in the aerosol. Such a smoking article also consists of at least two, but more often more, in particular four segments. One segment contains the aerosol forming material, which typically comprises tobacco, reconstituted tobacco, or tobacco processed by other processes. Other segments in the smoking article, some of which are optional, are used to direct the aerosol, cool the aerosol or filter the aerosol.

The segments are mostly encased by an encasing material. Paper is very often used as a wrapping material.

In the following, unless explicitly stated otherwise or otherwise directly derived from the context, "segment" is understood to mean the segment of a smoking article, which does not contain the aerosol-forming material, but is used, for example, to forward, cool or filter the aerosol.

Forming such segments from non-natural polymers such as cellulose acetate or polylactides is known from the prior art. After consumption of the smoking article, the smoking article must be disposed of appropriately. In many cases, however, the consumer simply throws away the consumed smoking article in the environment, and attempts to restrict this behavior through information or punishment have had little success.

Since cellulose acetate and polylactides are very slow to biodegrade in the environment, there is an interest in the industry to fabricate the segments of the smoking article from other materials that are more biodegradable. In addition, regulations are planned in the European Union, for example, which will significantly reduce or prohibit the use of non-natural polymers in smoking articles, so that for this reason there is also an interest in having alternative segments for smoking articles available.

Various requirements are placed on the segments in a smoking article. A first requirement is to filter the aerosol. This filtration is often selective, which means it removes certain substances from the aerosol and thus influences the taste of the aerosol. With regard to filtration, one would like to have both segments that have a particularly high filtration efficiency, for example if they are primarily used for filtration, and those that have a particularly low filtration efficiency, for example if they are primarily intended to forward or cool the aerosol.

Another requirement is to generate a certain resistance to draw. When smoking, the consumer expects a certain resistance, that is, a certain pressure difference, in order to suck in aerosol from the smoking article. The segments for smoking articles are therefore often designed in such a way that they have a certain draw resistance.

Another requirement is to cool the aerosol. Immediately after its formation, the aerosol has a temperature of several 100°C and must be cooled to a temperature that the consumer can tolerate while it flows through the smoking article. In the prior art, this is typically done by removing heat from the aerosol.

Finally, another requirement is to provide the smoking article with sufficient mechanical stability. During normal consumption of the smoking article, the consumer should not be able to accidentally squeeze the smoking article, which is why they must the segments have a certain hardness. This is partly achieved through the choice of a suitable covering material.

Attempts to combine all of these requirements with good biodegradability have so far not been sufficiently successful.

DE 10 2016 105 235 A1 discloses a filter paper for producing filters for smoking articles, in particular filter cigarettes, with the following properties: the filter paper comprises fibers comprising cellulose fibers, with at least 80% by weight of the filter paper being formed by long-fiber cellulose fibers. Of the fibers, a proportion of between 2% and 10% by number of fibers has a length of less than 0.2 mm. The air permeability of the filter paper measured according to ISO 2965:2009 is between 500 cm min-1 kPa-1 and 15000 cm min-1 kPa-1. The number-average length of the fibers in the filter paper is more than 1 mm and less than 5 mm, and the number-average width of the fibers in the filter paper is between 10 μm and 50 μm.

SUMMARY OF THE INVENTION

The object of the invention is to provide a segment for a smoking article that is more biodegradable than conventional segments in smoking articles and that is no worse than conventional segments in terms of filtration properties, cooling effect and draw resistance.

This object is achieved by a smoking article according to claim 1. Advantageous developments are specified in the dependent claims.

The inventors have found that certain fiber-based sheet materials are suitable for segments in smoking articles to at least meet the biodegradability requirement. All web-like materials made from staple fibers that can be formed into segments for smoking articles are referred to here as fiber-based web materials. Suitable fiber-based web materials are, in particular, paper or fleece. In the following, “web material” is understood without exception as a fiber-based web material for use in smoking articles.

The inventors have further found that a certain combination of properties of the web material and the segment produced from it allows the various additional requirements to be met in a particularly favorable manner.

In concrete terms, the segment according to the invention comprises a wrapping material and a web material which is wrapped by the wrapping material. The sheet material comprises at least 40% cellulosic fibers and less than 10% non-natural polymers, the percentages being based on the mass of the sheet material. Furthermore, the web material has a basis weight of at least 10 g/m ² and at most 70 g/m ² , a thickness of at least 25 μm and at most 400 μm. In the segment, said web material has an area of at least 20 cm ² and at most 90 cm ² per cm ³ volume of the segment. Without the covering material, the segment made of the web material has a density of at least 50 kg/m ³ and at most 300 kg/m ³ . The wrapping material is paper with a basis weight of at least 20 g/m ² and at most 150 g/m ² and has a flexural strength of at least 0.05Nmm and at most 0.90Nmm. Finally, for the density of the web material (ρ _Web ) in kg/m ³ , the density of the segment without wrapping material (ρ _Seg ) in kg/m ³ and the area of the web material in the segment per cm ³ volume of the segment (A- _Web ) in cm ² /cm ³ the following inequality must be satisfied $$1350\le {\rho }_{\mathit{Web}}+5\cdot {\rho }_{\mathit{seg}}+12\cdot A_{\mathit{Web}}\le 2600.$$

According to the findings of the inventors, the draw resistance, the filtration efficiency and the cooling effect of the segment are determined by the structure and amount of the web material in the segment. A porous structure of the web material increases heat transfer and filtration efficiency. In addition to the structure of the web material, the amount of web material in the segment also plays a role. It is specified on the one hand by the area of the web material in the segment per volume of the segment, with higher area per volume increasing draw resistance, filtration efficiency and heat transfer, and on the other hand by the density of the segment without wrapping material, with higher density primarily increasing draw resistance. In addition to the area available for heat transfer, the density of the web material and the segment also play a role in the cooling effect of the segment, in particular, because they influence the transfer of heat.

The inventors have now found that within the limits given above for the basis weight of the web material, the thickness of the web material, the density of the web material, the area of the web material per volume in the segment and the density of the segment without wrapping material, a particularly favorable combination then results Properties results, if for the from the density of the web material, the density of the segment without wrapping material and the area of the sheet material per volume of the segment, the above inequality is satisfied.

The sheet material in the segment of the smoking article comprises cellulosic fibers, with at least 40% of the mass of the sheet material being cellulosic fibers. Cellulose fibers consist of natural polymers and are easily biodegradable, which results in a first advantage of the invention. Another advantage essential to the invention derives from the fact that pulp fibers are hygroscopic. The aerosol in the smoking article contains water and the cellulose fibers can absorb some of this water and thus contribute to cooling the aerosol. In contrast to segments made of other materials, no more heat is dissipated, but part of the water in the aerosol is retained with the thermal energy stored in the water. An aerosol thus reaches the consumer of the smoking article, the temperature of which is not necessarily significantly reduced, but which contains significantly less thermal energy and is therefore more tolerable for the consumer.

The proportion of cellulose fibers in the web material is therefore preferably higher and is preferably at least 60%, particularly preferably at least 90% and very particularly preferably at least 99%, in each case based on the mass of the web material.

The cellulose fibers can be wood cellulose fibers from hardwoods or conifers, but also from other plants such as hemp, flax, sisal, jute, abaca or esparto grass and are produced according to the methods known from the prior art. Mixtures of pulp fibers from different origins can be used.

In order to ensure good biodegradability of the segment, the web material should contain less than 10% of its mass of non-natural polymers. Natural polymers are polymers that have been obtained directly from natural raw materials without any chemical change or without changing the composition, or are chemically identical to polymers obtained from nature. Concretely, pulp fibers consist of natural polymers, and regenerated cellulose fibers also belong to natural polymers. In the case of cellulose acetate or polylactides, on the other hand, chemical changes have taken place so that they belong to the non-natural polymers, and although the starting materials occur in nature, these starting materials have at least been modified in such a way that rapid biodegradability is no longer guaranteed. Likewise, all polymers derived from mineral oils such as polyethylene, polypropylene, polyester or polystyrene are not natural polymers.

Preferably, the sheet material contains less than 5% by mass of the sheet material non-natural polymers and more preferably less than 1% by mass of the sheet material. Optimum biodegradability occurs when the web material does not contain any non-natural polymers, which is why this is a particularly preferred embodiment.

The web material can contain fibers made from regenerated cellulose, such as viscose fibers, modal fibers, ^Lyocell® or ^Tencel® , the proportion of which is preferably less than 60% of the mass of the web material and particularly preferably less than 40% of the mass of the web material. The amount of regenerated cellulose fibers can be chosen to further optimize the filtration efficiency.

The web material can also contain fillers, the fillers preferably being formed by calcium carbonate, magnesium oxide, magnesium hydroxide, aluminum hydroxide, titanium dioxide and silicates or mixtures thereof. A particularly preferred filler is precipitated calcium carbonate. The proportion of fillers based on the mass of the web material is preferably at least 0%, particularly preferably at least 5% and very particularly preferably at least 10% and preferably at most 40%, particularly preferably at most 35% and very particularly preferably at most 30%. Since fillers absorb significantly less water than cellulose fibers, an increase in the proportion of fillers for the same basis weight of the web material can contribute to a reduction in the filtration efficiency for water. This can also influence the cooling effect of the segment.

The web material can also be coated. In a preferred embodiment, the web material is coated with polyvinyl alcohol or a polysaccharide, which reduces the filtration efficiency for water and thus the aerosol is dried less. In a particularly preferred embodiment, the polysaccharide is selected from the group consisting of starch, carboxymethyl cellulose, guar, dextrin, pectin or mixtures thereof. It should be noted that polyvinyl alcohol is not a natural polymer and the amount of non-natural polymers does not exceed 10% of the mass of the web material.

The web material can also be impregnated. In contrast to coating, with impregnation the applied composition not only remains on the surface but penetrates significantly into the structure of the web material. In a preferred embodiment, the web material is impregnated with glycerol or propylene glycol. these substances can increase the filtration efficiency for glycerol, which often acts as a humectant in the aerosol forming material of the smoking article and promotes the formation of the aerosol.

The sheet material may also contain flavorings to affect the taste of the aerosol. The flavorings can be contained in the web material in chemically bound form or physically bound form, for example encapsulated. The flavorings are preferably selected from the group consisting of menthol, ethyl vanillin glucoside, vanillin and ethyl vanillin.

Other components of the web material, such as sizing agents, for example AKD, ASA or resins or other additives and processing aids can be selected by the person skilled in the art based on his experience, although it should be noted that the amount of non-natural polymers must be less than 10% of the mass of the web material .

The basis weight of the web material is between 10 g/m ² and 70 g/m ² and preferably between 20 g/m ² and 60 g/m ² and particularly preferably between 25 g/m ² and 50 g/m ² . The basis weight can be determined according to ISO 536:2012. The choice of basis weight influences the processability of the web material, in particular the process of crimping or folding, and the material costs for the segment. The preferred intervals reconcile the cost of materials with the segment properties achieved particularly well.

The thickness of the web material is between 25 μm and 400 μm and preferably between 35 μm and 150 μm and particularly preferably between 40 μm and 100 μm. As with basis weight, the caliper of the web material is important to processability and the preferred intervals provide a caliper particularly well suited for crimping or folding for desired segment properties. The thickness can be determined according to ISO 534:2011.

The basis weight and the caliper together influence the properties of the segment made from the web material via the density. The density of the web material is preferably between 100 kg/m ³ and 1200 kg/m ³ , more preferably between 200 kg/m ³ and 700 kg/m ³ and most preferably between 300 kg/m ³ and 600 kg/m ³ . The density describes the pore structure of the web material and is therefore an important parameter for the filtration efficiency, the heat transfer and the draw resistance. The preferred intervals allow for a favorable combination of draw resistance and filtration efficiency. The density can be determined according to ISO 534:2011.

The segment contains between 20 cm ² and 90 cm ² sheet material per cm ³ volume of the segment, preferably between 30 cm ² /cm ³ and 80 cm ² /cm ³ and more preferably between 35 cm ² /cm ³ and 70 cm ² /cm ³ , each related to the volume of the segment. The area of the web material per volume of the segment describes how densely the web material is packed in the segment. It therefore affects the draw resistance, but also the filtration properties, the heat transfer and the hardness of the segment. The area of the sheet material can be determined, for example, by weighing the sheet material and calculating from the nominal or measured basis weight of the sheet material.

The density of the segment itself, without the covering material, is between 50 kg/m ³ and 300 kg/m ³ , preferably between 60 kg/m ³ and 250 kg/m ³ and particularly preferably between 70 kg/m ³ and 200 kg/m ^m3 . This parameter also has a significant impact on the draw resistance, filtration efficiency and segment hardness. The density of the segment is given without the wrap material as the wrap material has little effect on draw resistance, filtration efficiency or heat transfer. The density of the segment can be determined by calculation. First of all, the volume of the segment is determined, which can be calculated from the diameter and the length, for example, in the case of a cylindrical segment. The influence of the cladding material on the diameter can be neglected. The mass of the segment can be determined by weighing with the segment wrapped in the wrapping material. The mass of the wrapping material can be determined from the area of the wrapping material and the nominal or measured basis weight of the wrapping material. For example, for a typical cylindrical segment, the area of the wrapping material is given by the perimeter of the segment and the overlap of the wrapping material on itself and the length of the segment.

The mass of the covering material is subtracted from the mass of the segment with covering material and its density is calculated by dividing it by the volume of the segment. A numerical example is detailed below.

berechnet wird, wobei

• ρ_Web die Dichte des Bahnmaterials in kg/m³,
• ρ_Seg die Dichte des Segments ohne Umhüllungsmaterial in kg/m³, und
• A_Web die Fläche des Bahnmaterials pro Volumen des Segments in cm²/cm³ sind.

Since the density of the web material, the density of the segment without wrapping material, and the area of the web material in the segment per volume of the segment all affect and are in a complex interrelationship the draw resistance, filtration efficiency, and heat transfer of the segment, the inventors have found that only with a certain combination of these properties meet the requirements of the segment can be fulfilled well. It has been shown that a parameter Z calculated from these properties is decisive, which is determined by $$Z={\rho }_{\mathit{Web}}+5\cdot {\rho }_{\mathit{seg}}+12\cdot A_{\mathit{Web}}$$

is calculated, where

• ρ _Web is the density of the web material in kg/m ³ ,
• ρ _Seg is the density of the segment without cladding material in kg/m ³ , and
• A _Web is the area of web material per volume of segment in cm ² /cm ³ .

This parameter Z should be at least 1350 and at most 2600 and preferably at least 1400 and at most 2400. This is the only way to obtain a segment with favorable properties and, in the preferred intervals, a particularly favorable compromise between draw resistance and filtration properties.

The wrapping material of the segment is a paper with a basis weight of at least 20 g/m ² and at most 150 g/m ² and more preferably a paper with a basis weight of at least 50 g/m ² and at most 120 g/m ² . In order to achieve favorable properties of the segment, the density of the segment and thus the hardness are comparatively low. Therefore, covering materials with a basis weight of 50 g/m ² to 150 g/m ² can further improve the hardness of the segment. However, the weight per unit area must not be too high, because otherwise the restoring forces of the encapsulation material make it difficult to produce a segment, in particular to bond the encapsulation material to itself.

The flexural rigidity of the covering material can be just as important as the weight per unit area in order to set a favorable hardness for the segment. The bending stiffness should therefore be at least 0.05 Nmm and at most 0.90 Nmm, preferably at least 0.10 Nmm and at most 0.80 Nmm. Flexural stiffness can be measured according to ISO 5628:2012, specifically the two-point method described in that standard. The bending stiffness can depend on the direction in which the sample was taken from the sheet material. The features indicated by the above preferred and particularly preferred interval are met if the flexural rigidity in at least one direction is in the indicated preferred or particularly preferred interval.

The segment according to the invention is preferably cylindrical and preferably has a diameter of at least 5 mm and at most 9 mm, particularly preferably at least 7 mm and at most 8.5 mm.

The segment according to the invention is preferably at least 4 mm and at most 40 mm long, particularly preferably at least 6 mm and at most 35 mm and very particularly preferably at least 10 mm and at most 28 mm.

The segment according to the invention can be part of a smoking article, so that a smoking article according to the invention comprises an aerosol-forming material and the segment according to the invention.

In a preferred embodiment, the smoking article is a filter cigarette comprising at least one segment according to the invention and a further segment containing tobacco. In a particularly preferred embodiment, the segment according to the invention is a segment of the filter of a filter cigarette.

In another preferred embodiment, the smoking article is a smoking article that contains an aerosol-forming material that is only heated but not burned when the smoking article is used as intended, and that contains at least one segment according to the invention and a filter segment, the at least one segment according to the invention between the aerosol-forming Material and the filter segment is arranged. In this arrangement, the at least one segment according to the invention serves primarily to cool the aerosol.

The segment according to the invention can be produced from sheet material by methods known from the prior art. Such methods typically include crimping or folding the sheet material, forming a continuous strand from the sheet material, wrapping the continuous strand with a wrapping material, and cutting the wrapped strand into segments of the desired size.

Smoking articles using the segment of the present invention can be manufactured by methods well known in the art.

BRIEF DESCRIPTION OF THE FIGURES

1

shows a table (Table 1) summarizing the compositions of 25 web materials.

2

shows a table (Table 2) in which characteristic dimensions of the web materials (width, basis weight, thickness, density) of the 25 web materials of Table 1 are summarized.

3

Figure 12 shows a table (Table 3) summarizing characteristic quantities of 25 segments (mass, density, area, parameter Z) formed from the web materials of Tables 1 and 2.

4

Figure 4 shows a table (Table 4) summarizing functional properties of the segments of Table 3 (draw resistance, filtration efficiency with respect to nicotine, water and glycerol).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will now be described in more detail using some embodiments according to the invention and compared with examples not according to the invention.

Various fiber-based web materials were prepared according to papermaking processes known in the art and cut into rolls with a width of 175 mm to 315 mm. The rolls of sheet material were crimped and an endless strand was produced and covered with a cover material with a basis weight of 78 g/m ² . The strand of wrapping material was 7.85 mm in diameter, with the wrapping material having a width of 27 mm and therefore overlapping about 2.3 mm for bonding to itself.

The composition of the web materials is given in Table 1. All web materials were made of wood pulp, the two web materials nos. 22 and 23 also used Lyocell ^® fibers, whereby the stated percentage of 40% refers to the mass of Lyocell ^® fibers in the total fiber mass in the web material. Sheet materials 4-6, 12 and 13 also contained 29.5% by mass of precipitated calcium carbonate (CaCO ₃ ).

Sheets 16-21, 24 and 25 were coated with an oxidized starch and sheets 14, 15, 18 and 19 were saturated with glycerol. Sheet materials 20 and 21 were impregnated with propylene glycol.

The basis weight of the web materials was determined according to ISO 536:2012 and the thickness and density according to ISO 534:2011. The results are shown in Table 2, in which the sheet material numbers correspond to those in Table 1.

The strands made from the web materials were cut into rods each 108 mm long and their mass was determined by weighing.

The data for the bars made from sheet materials 1-25 are given in Table 3, again with sheet material numbers corresponding to those in Table 1. The mass in Table 3 is the mass of a 108 mm long bar with a covering material with a weight per unit area of 78 g/m ² . From the mass of the rod and the known geometry, the density was calculated as follows.

The mass of the wrapping material, which is 27 mm wide and 108 mm long, is $$78\mathrm{G}/{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">m</figure-callout>}}^2\times 0.027\mathrm{m}\times 0.108\mathrm{m}=0.227\mathrm{G}.$$

The volume of the stick was calculated from the known geometry of the stick, i.e $$\mathrm{\pi }/4\times {\left(7.85\mathrm{<figure-callout\; id="2"\; label="mm"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">mm</figure-callout>}\right)}^2\times 108\mathrm{mm}=5227{\mathrm{<figure-callout\; id="3"\; label="mm"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">mm</figure-callout>}}^3.$$

The thickness of the wrapping material was neglected. The mass of the covering material was subtracted from the mass of the rod with covering material and the result divided by the volume. For example, the density of the rod made from web material 1 results in this way $$\left(0.71\mathrm{G}-0.227\mathrm{G}\right)/5227{\mathrm{<figure-callout\; id="3"\; label="mm"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">mm</figure-callout>}}^3=92.4\mathrm{kg}/{\mathrm{<figure-callout\; id="3"\; label="m"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">m</figure-callout>}}^3.$$

berechnet wird, wobei

• ρ_Web die Dichte des Bahnmaterials in kg/m³,
• ρ_Seg die Dichte des Segments ohne Umhüllungsmaterial in kg/m³, und
• A_Web die Fläche des Bahnmaterials pro Volumen des Segments in cm²/cm³ ist.

Also given in Table 3 is the parameter Z, which consists of $$Z={\rho }_{\mathit{Web}}+5\cdot {\rho }_{\mathit{seg}}+12\cdot A_{\mathit{Web}}$$

is calculated, where

• ρ _Web is the density of the web material in kg/m ³ ,
• ρ _Seg is the density of the segment without cladding material in kg/m ³ , and
• A _Web is the area of web material per volume of segment in cm ² /cm ³ .

The Z parameter is independent of the geometry, in particular the diameter and length of the rod or segment, and characterizes only the internal structure of the segment.

The tensile strength of the 108 mm long bars was measured according to ISO 6565. Segments with a length of 18 mm were cut from the rods and smoking articles were made from them.

The smoking article was a so-called heated tobacco product in which the tobacco contained in the smoking article was only heated up. The smoking article consisted of a segment with the tobacco in the direction of flow, followed by a transfer segment in which the aerosol can condense, and further followed by the segment according to the invention, which here serves primarily to cool the aerosol, and finally a filter segment.

The smoking articles were heated in a commercially available heater and smoked according to the procedure given in ISO 3308. The filtration efficiency for nicotine, water and glycerol was measured for the segments made from sheet materials 8-25. The filtration efficiency for a substance is the difference between the amount of substance that flows into the segment and the amount of substance that flows out of the segment, based on the amount of substance flowing into the segment. The filtration efficiency is expressed as a percentage and was determined for nicotine, water and glycerol in this way for an 18 mm long segment.

Table 4 shows the draw resistance of a 108mm rod and the filtration efficiencies of a 18mm segment for nicotine, water and glycerol. Again, the web material numbers correspond to those in Table 1.

The segments made from sheet materials 1-25 are segments of the present invention having a Z parameter of about 1300 to about 2250. The draw resistance of the 108 mm long rod is between 17.9 mmWG and 63.9 mmWG, allowing the design of segments that either direct the aerosol and only offer a low draw resistance or that filter the aerosol and also allow the draw resistance of the smoking article to increase. In particular, a comparison of web materials 2 and 11, which are identical in composition, shows the influence of the density of the segment on the draw resistance. A segment of sheet material 2 with a segment density of 73.3 kg/m ³ gives a draw resistance (108 mm) of 23.8 mmWG while a segment made of sheet material 11 with a density of 170.5 kg/m ³ gives a draw resistance (108mm) by 54.5mm WG. This shows the importance of the density of the segment, which is why it is an essential component of the Z parameter. However, the draw resistance is not determined solely by the density of the segment.

The web materials 6 and 7 have a similar basis weight, but the web material 6 contains 29.5% calcium carbonate and therefore has a significantly higher density. The segments made from this have similar densities and the area of the web material per volume of the segment is also similar. Nevertheless, they differ significantly in the draw resistance, which is 63.9 mmWG for the bar (108 mm) made from web material 6 and only 30.5 mmWG for the bar (108 mm) made from web material 7. This shows that the density of the web material itself has an independent significance for the properties of the segment produced from it and is therefore also included as an essential property in the parameter Z.

The surface area of the web material per volume of the segment depends on the density of the web material and the density of the segment without the covering material and is therefore also an important property for the draw resistance and is therefore also included in the parameter Z.

The segments of the starch-coated sheet materials 16-21 all show a lower filtration efficiency for water than the segments from the comparable sheet materials 8, 9 and 11, while they hardly differ in the filtration efficiencies for nicotine and glycerol. This shows that an oxidized starch coating can be used to adjust the filtration efficiency for water.

The impregnation of web materials 18-21 with glycerol or propylene glycol results in a significantly higher filtration efficiency for nicotine and glycerol in the segments made from this compared to the segments made of web materials 16 and 17, which have no such impregnation. So the filtration efficiency for nicotine and glycerol can be adjusted through the impregnation.

All in all, all segments made from web materials 1-25 are useful as a segment in a smoking article and can be used both primarily to cool the aerosol and to filter the aerosol. The biodegradability of all segments made from sheet materials 1-25 resulted directly from the components used and was not tested further. It was found that with the segments according to the invention, favorable properties are obtained for use in smoking articles and, in addition, excellent biodegradability is achieved.

The following two examples not according to the invention show that the parameter Z is essential for differentiating between segments according to the invention and segments not according to the invention.

und liegt damit außerhalb des erfindungsgemäßen Intervalls von 1350 bis 2600.A segment was made from sheet 7 with an unwrapped density of 90.4 kg/m ³ and an area of sheet material per volume of segment of 36.9 cm ² /cm ³ . The parameter Z for this segment turned out to be $$350.0+5\cdot 90.4+12\cdot 36.9=1244.8$$

and is therefore outside the interval of 1350 to 2600 according to the invention.

The 108 mm long rod made from this sheet material only has a draw resistance of 12.3 mmWG, which is too low for use in smoking articles. In addition, the hardness of the segment is not sufficient for further processing into a smoking article, despite the wrapping material at 78 g/m ² . It should be noted that this segment satisfies all of the requirements of the invention, with the exception of those for the Z parameter.

und liegt damit außerhalb des erfindungsgemäßen Intervalls von 1350 bis 2600A segment was prepared from sheet 12 with an unwrapped density of 233.9 kg/m ³ and an area of sheet material per volume of segment of 89.9 cm ² /cm ³ . The parameter Z for this segment turned out to be $$604.7+5\cdot 233.9+12\cdot 89.9=2853.6$$

and is therefore outside the interval of 1350 to 2600 according to the invention

The filtration efficiency of this segment for water was over 65% despite the content of calcium carbonate in the web material 12 and thus produces an aerosol that is too dry and therefore leads to a taste that is unacceptable to the consumer. It should be noted that this segment also meets all of the requirements according to the invention, with the exception of those for the Z parameter.

The two comparative examples not according to the invention thus show that the parameter Z is essential in order to obtain a segment with satisfactory properties.

Claims (15)

1. Smoking article, comprising an aerosol-forming material which is only heated during smoking but is not burnt, and a segment comprising a fiber-based web material and a wrapping material, which wraps the fiber-based web material, wherein the fiber-based web material

   - comprises at least 40% pulp fibers and less than 10% non-natural polymers, respectively with respect to the mass of the web material,

   - has a basis weight of at least 10 g/m² and at most 70 g/m², and

   - has a thickness of at least 25 µm and at most 400 µm,

   wherein said web material in the segment has an area of at least 20 cm² and at most 90 cm² per cm³ volume of the segment,

   wherein the segment without the wrapping material has a density of at least 50 kg/m³ and at most 300 kg/m³, and

   wherein a parameter Z, which is defined by Z = ρ_Web + 5 · ρ_Seg + 12 . A_Web, satisfies the inequality 1350 ≤ Z ≤ 2600, wherein

   ρ_Web is the density of the web material in kg/m³,

   pseg is the density of the segment without wrapping material in kg/m³, and

   A_Web is the area of the web material per volume of the segment in cm²/cm³,

   wherein the wrapping material is formed by a paper with a basis weight of at least 20 g/m² and at most 150 g/m², and

   wherein the wrapping material has a bending stiffness of at least 0.05 Nmm and at most 0.90 Nmm.
2. Smoking article according to claim 1, wherein the content of pulp fibers in the web material is at least 60%, preferably at least 90% and particularly preferably at least 99%, respectively with respect to the mass of the web material.
3. Smoking article according to claim 1 or 2, wherein the pulp fibers are formed by wood pulp fibers which are sourced from deciduous trees or coniferous trees, from other plants, in particular hemp, flax, sisal, jute, abaca or esparto grass, or mixtures thereof.
4. Smoking article according to one of the preceding claims, wherein the web material contains less than 5% of its mass of non-natural polymers, preferably contains less than 1% of its mass of non-natural polymers, and particularly preferably contains no non-natural polymers.
5. Smoking article according to one of the preceding claims, wherein the web material contains fibers from regenerated cellulose, in particular viscose fibers, modal fibers, Lyocell^® or Tencel^®, wherein their content is preferably less than 60% of the mass of the web material and particularly preferably less than 40% of the mass of the web material.
6. Smoking article according to one of the preceding claims, wherein the web material contains filler materials, wherein the filler materials are preferably formed by calcium carbonate, in particular precipitated calcium carbonate, magnesium oxide, magnesium hydroxide, aluminum hydroxide, titanium dioxide, silicates or mixtures thereof,
   wherein the content of filler materials with respect to the mass of the web material preferably is at least 0%, more preferably at least 5% and particularly preferably at least 10%, and preferably at most 50%, more preferably at most 35% and particularly preferably at most 30%.
7. Smoking article according to one of the preceding claims, wherein the web material is coated, in particular with polyvinyl alcohol or a polysaccharide, wherein the polysaccharide is preferably selected from the group consisting of starch, carboxymethylcellulose, guar, dextrin, pectin or mixtures thereof, and/or
   wherein the web material is impregnated, in particular with glycerol or propylene glycol.
8. Smoking article according to one of the preceding claims, wherein the web material contains flavors, wherein preferably, the flavors are contained in the web material in a chemically bound form or in a physically bound form, for example encapsulated, wherein the flavors are preferably selected from the group consisting of menthol, ethyl vanillin glucoside, vanillin and ethyl vanillin.
9. Smoking article according to one of the preceding claims, wherein the basis weight of the web material is between 20 g/m² and 60 g/m², preferably between 25 g/m² and 50 g/m².
10. Smoking article according to one of the preceding claims, wherein the thickness of the web material is between 35 µm and 150 µm, preferably between 40 µm and 100 µm.
11. Smoking article according to one of the preceding claims, wherein the density of the web material is between 100 kg/m³ and 1200 kg/m³, preferably between 200 kg/m² and 700 kg/m³ and particularly preferably between 300 kg/m³ and 600 kg/m³.
12. Smoking article according to one of the preceding claims, which contains between 30 cm²/cm³ and 80 cm²/cm³, preferably between 35 cm²/cm³ and 70 cm²/cm³ of web material per cm³ volume of the segment.
13. Smoking article according to one of the preceding claims, with a density, without the wrapping material, which is between 60 kg/m³ and 250 kg/m³, preferably between 70 kg/m³ and 200 kg/m³, and/or

    wherein the parameter Z is at least 1400 and at most 2400, and/or

    wherein the wrapping material is formed by paper with a basis weight of at least 50 g/m² and at most 120 g/m².
14. Smoking article according to one of the preceding claims, wherein the wrapping material has a bending stiffness of at least 0.10 Nmm and at most 0.80 Nmm, and/or wherein the segment is cylindrical and preferably has a diameter of at least 5 mm and at most 9 mm, particularly preferably of at least 7 mm and at most 8.5 mm, and/or wherein the segment is at least 4 mm and at most 40 mm long, preferably is at least 6 mm and at most 35 mm long and particularly preferably is at least 10 mm and at most 28 mm long.
15. Smoking article according to one of the preceding claims, wherein the segment is arranged between the aerosol-forming material and a filter segment.

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