AEROSOL-GENERATING ARTICLE FILTER HAVING NOVEL FILTRATION MATERIAL

Abstract

An aerosol-generating article is provided, including: an aerosol-generating substrate; and a filter in axial alignment with the aerosol-generating substrate, the filter including at least one filter segment of filtration material formed of a plurality of fibres including a polyhydroxyalkanoate compound, in which the fibres have a denier per filament (dpf) of between 5.0 dpf and 12.0 dpf, in which the filter segment includes at least 20 percent by weight of the polyhydroxyalkanoate compound, and in which a resistance to draw (RTD) of the filter segment is between 10 millimetres H.sub.2O and 25 millimetres H.sub.2O. A filter for an aerosol-generating article is also provided.

Claims

1.-13. (canceled)

14. An aerosol-generating article, comprising: an aerosol-generating substrate; and a filter in axial alignment with the aerosol-generating substrate, the filter comprising at least one filter segment of filtration material formed of a plurality of fibres comprising a polyhydroxyalkanoate compound, wherein the fibres have a denier per filament (dpf) of between 5.0 dpf and 12.0 dpf, wherein the at least one filter segment comprises at least 20 percent by weight of the polyhydroxyalkanoate compound, and wherein a resistance to draw (RTD) of the at least one filter segment is between 10 millimetres H.sub.2O and 25 millimetres H.sub.2O.

15. The aerosol-generating article according to claim 14, wherein the plurality of fibres have a round cross-sectional shape and provide a total external surface area within the filter segment of between 0.08 square meters per gram and 0.12 square meters per gram.

16. The aerosol-generating article according to claim 14, wherein the plurality of fibres have a Y-shaped cross-sectional shape and provide a total external surface area within the filter segment of between 0.15 square meters per gram and 0.21 square meters per gram.

17. The aerosol-generating article according to claim 14, wherein a total denier of the fibres is between 15,000 and 30,000.

18. The aerosol-generating article according to claim 14, wherein the filtration material further comprises a plurality of fibres of at least one additional, biodegradable polymer.

19. The aerosol-generating article according to claim 14, wherein the at least one filter segment further comprises at least 5 percent by weight of polyethylene glycol.

20. The aerosol-generating article according to claim 14, where the at least one filter segment has an average radial hardness of at least 80 percent.

21. The aerosol-generating article according to claim 14, wherein the at least one filter segment is circumscribed by a wrapper having a basis weight of at least 100 grams per square metre (gsm).

22. The aerosol-generating article according to claim 14, wherein the at least one filter segment is in the form of a hollow tubular element.

23. The aerosol-generating article according to claim 14, wherein the aerosol-generating substrate has a length of between 5 millimetres and 15 millimetres.

24. The aerosol-generating article according to claim 14, wherein the at least one filter segment further comprises a capsule within the plurality of fibres.

25. A filter for an aerosol-generating article, the filter comprising: at least one filter segment of filtration material comprising a plurality of fibres comprising a polyhydroxyalkanoate compound, wherein the fibres have a denier per filament (dpf) of between 5.0 dpf and 12.0 dpf, wherein the at least one filter segment comprises at least 20 percent by weight of the polyhydroxyalkanoate compound, and wherein a resistance to draw (RTD) of the at least one filter segment is between 10 millimetres H.sub.2O and 25 millimetres H.sub.2O.

Description

[0107] The invention will now be further described with reference to the figures in which:

[0108] FIG. 1 shows a schematic longitudinal cross-sectional view of an aerosol-generating article according to a first embodiment of the invention, for use with an aerosol-generating device comprising a heater element;

[0109] FIG. 2 shows a schematic longitudinal cross-sectional view of an aerosol-generating article according to a second embodiment of the invention, comprising an integral heat source; and

[0110] FIG. 3 shows a schematic longitudinal cross-sectional view of an aerosol-generating article according to a third embodiment of the invention; and

[0111] FIG. 4 shows a schematic longitudinal cross-sectional view of an aerosol-generating system comprising an electrically operated aerosol-generating device and the aerosol-generating article shown in FIG. 1.

[0112] The aerosol-generating article 10 shown in FIG. 1 comprises a rod of aerosol-generating substrate 12, a support element provided as a hollow tubular element 14, a cooling element 16, and a mouth end filter segment 18. These four elements are arranged sequentially and in coaxial alignment and are circumscribed by a substrate wrapper 20 to form the aerosol-generating article 10. The aerosol-generating article 10 has a mouth end 22 and a distal end 24 located at the opposite end of the article to the mouth end 22. The aerosol-generating article 10 shown in FIG. 1 is particularly suitable for use with an electrically operated aerosol-generating device comprising a heater for heating the rod of aerosol-generating substrate.

[0113] In use air is drawn through the aerosol-generating article by a user from the distal end 24 to the mouth end 22. The distal end 24 of the aerosol-generating article may also be described as the upstream end of the aerosol-generating article 10 and the mouth end 22 of the aerosol-generating article 10 may also be described as the downstream end of the aerosol-generating article 10. Elements of the aerosol-generating article 10 located between the mouth end 22 and the distal end 24 can be described as being upstream of the mouth end 22 or, alternatively, downstream of the distal end 24.

[0114] The aerosol-generating substrate 12 is located at the extreme distal or upstream end of the aerosol-generating article 10. In the embodiment illustrated in FIG. 1, the aerosol-generating substrate 12 comprises a gathered sheet of crimped homogenised tobacco material circumscribed by a wrapper. The crimped sheet of homogenised tobacco material comprises glycerin as an aerosol former.

[0115] The support element 14 is located immediately downstream of the aerosol-generating substrate 12 and abuts the aerosol-generating substrate 12. In the embodiment shown in FIG. 1, the support element is a hollow tube formed of a fibrous filtration material. The support element 14 locates the aerosol-generating substrate 12 at the extreme distal end 24 of the aerosol-generating article 10 so that it can be penetrated by a heating element of an aerosol-generating device. In effect, the support element 14 acts to prevent the aerosol-generating substrate 16 from being forced downstream within the aerosol-generating article 10 towards the aerosol-cooling element 16 when a heating element of an aerosol-generating device is inserted into the aerosol-generating substrate 12. The support element 14 also acts as a spacer to space the aerosol-cooling element 16 of the aerosol-generating article 10 from the aerosol-generating substrate 12.

[0116] The aerosol-cooling element 16 is located immediately downstream of the support element 14 and abuts the support element 16. In use, volatile substances released from the aerosol-generating substrate 12 pass along the aerosol-cooling element 16 towards the mouth end 22 of the aerosol-generating article 10. The volatile substances may cool within the aerosol-cooling element 16 to form an aerosol that is inhaled by the user. In the embodiment illustrated in FIG. 1, the aerosol-cooling element comprises a tubular element 20. The crimped and gathered sheet of polylactic acid defines a plurality of longitudinal channels that extend along the length of the aerosol-cooling element 40.

[0117] The filter segment 18 is located immediately downstream of the aerosol-cooling element 16 and abuts the aerosol-cooling element 16. In the embodiment illustrated in FIG. 1, the filter segment 18 comprises a single cylindrical plug of a fibrous filtration material formed of a plurality of PHA fibres having a denier per filament of approximately 8.0 and a total denier of approximately 15,000. The PHA fibres have a round cross-sectional shape and are substantially longitudinally aligned with each other along the length of the filter segment. The external surface area of the PHA fibres corresponds to about 0.1 square metres per gram. The PHA fibres have been formed by a melt spinning process and are crimped. The plug of fibrous filtration material is circumscribed by a plug wrap (not shown).

[0118] The aerosol-generating article 100 shown in FIG. 2 comprises a combustible heat source 112, a rod of aerosol-generating substrate 114, a transfer element 116, an aerosol-cooling element, 118, a spacer element 120 and a mouthpiece filter segment 122. These elements are arranged sequentially and in coaxial alignment and are circumscribed by a substrate wrapper to form the aerosol-generating article 100.

[0119] The combustible heat source 112 comprises a substantially circularly cylindrical body of carbonaceous material, having a length of about 10 millimetres. The combustible heat source 112 is a blind heat source. In other words, the combustible heat source 112 does not comprise any air channels extending therethrough.

[0120] The rod of aerosol-generating substrate 114 is arranged at a proximal end of the combustible heat source 112. The aerosol-generating substrate 114 comprises a substantially circularly cylindrical plug of tobacco material 124 circumscribed by filter plug wrap 126.

[0121] A non-combustible, substantially air impermeable first barrier 128 is arranged between the proximal end of the combustible heat source 112 and a distal end of the aerosol-generating substrate 114. The first barrier 128 comprises a disc of aluminium foil. The first barrier 128 also forms a heat-conducting member between the combustible heat source 112 and the aerosol-generating substrate 114, for conducting heat from the proximal face of the combustible heat source 112 to the distal face of the aerosol-generating substrate 114.

[0122] A heat-conducting element 130 circumscribes a proximal portion of the combustible heat source 112 and a distal portion of the aerosol-forming substrate 114. The heat-conducting element 130 comprises a tube of aluminium foil. The heat-conducting element 130 is in direct contact with the proximal portion of the combustible heat source 112 and the filter plug wrap 126 of the aerosol-generating substrate 114.

[0123] The mouthpiece filter 122 comprises a single cylindrical plug 126 of a fibrous filtration material formed of a plurality of PHA fibres having a denier per filament of approximately 8.0 and a total denier of approximately 15,000. The PHA fibres have a round cross-sectional shape and are substantially longitudinally aligned with each other along the length of the filter segment. The total external surface area of the PHA fibres corresponds to about 0.1 square metres per gram. The PHA fibres have been formed by a melt spinning process and are crimped. The plug of fibrous filtration material is circumscribed by a plug wrap (not shown).

[0124] The aerosol-generating article 310 shown in FIG. 3 is a combustible smoking article comprising an aerosol-generating substrate 312 and a filter 314 arranged in coaxial alignment with each other. The aerosol-generating substrate 312 comprises a tobacco rod circumscribed by an outer wrapper (not shown). A tipping wrapper 316 circumscribes both the filter 314 and an end portion of the aerosol-generating substrate 312 and attaches the filter 314 to the aerosol-generating substrate 312.

[0125] The filter 314 comprises a single cylindrical plug 318 of a fibrous filtration material formed of PHA fibres having a denier per filament of approximately 8.0 and a total denier of approximately 15,000. The PHA fibres have a round cross-sectional shape and are substantially longitudinally aligned with each other along the length of the filter segment. The total external surface area of the PHA fibres corresponds to about 0.1 square metres per gram. The PHA fibres have been formed by a melt spinning process and are crimped. The plug of fibrous filtration material is circumscribed by a plug wrap (not shown).

[0126] FIG. 4 shows a portion of an electrically operated aerosol-generating system 200 that utilises a heater blade 210 to heat the rod of aerosol-generating substrate 12 of the aerosol-generating article 10 shown in FIG. 1. The heater blade 210 is mounted within an aerosol-generating article chamber within a housing of an electrically operated aerosol-generating device 212. The aerosol-generating device 212 defines a plurality of air holes 214 for allowing air to flow to the aerosol-generating article 10, as illustrated by the arrows in FIG. 4. The aerosol-generating device 212 comprises a power supply and electronics, which are not shown in FIG. 4.