NOVEL AEROSOL-GENERATING SUBSTRATE

Abstract

An aerosol-generating article is provided, including an aerosol-generating substrate, the aerosol-generating substrate formed of a homogenised plant material, including: between 1 percent by weight and 65 percent by weight of non-tobacco plant particles, on a dry weight basis; between 15 percent by weight and 55 percent by weight of aerosol former, on a dry weight basis; between 5 percent by weight and 10 percent by weight of cellulose ether, on a dry weight basis; and between 5 percent by weight and 50 percent by weight of additional cellulose, on a dry weight basis, in which the additional cellulose is in a form of isolated cellulose and is not derived from the non-tobacco plant particles, and in which a ratio of additional cellulose to cellulose ether in the homogenised plant material is at least 2.

Claims

1.-19. (canceled)

20. An aerosol-generating article comprising an aerosol-generating substrate, the aerosol-generating substrate formed of a homogenised plant material, comprising: between 1 percent by weight and 65 percent by weight of non-tobacco plant particles, on a dry weight basis; between 15 percent by weight and 55 percent by weight of aerosol former, on a dry weight basis; between 5 percent by weight and 10 percent by weight of cellulose ether, on a dry weight basis; and between 5 percent by weight and 50 percent by weight of additional cellulose, on a dry weight basis, wherein the additional cellulose is in a form of isolated cellulose and is not derived from the non-tobacco plant particles, and wherein a ratio of additional cellulose to cellulose ether in the homogenised plant material is at least 2.

21. The aerosol-generating substrate according to claim 20, wherein the homogenised plant material further comprises at least 1 percent by weight of tobacco particles.

22. An aerosol-generating article comprising an aerosol-generating substrate, the aerosol-generating substrate formed of a homogenised plant material, comprising: between 1 percent by weight and 65 percent by weight of tobacco particles, on a dry weight basis; between 15 percent by weight and 55 percent by weight of aerosol former, on a dry weight basis; between 5 percent by weight and 10 percent by weight of cellulose ether, on a dry weight basis; and between 5 percent by weight and 50 percent by weight of additional cellulose, on a dry weight basis, wherein the additional cellulose is in a form of isolated cellulose and is not derived from the tobacco particles, and wherein the ratio of additional cellulose to cellulose ether in the homogenised plant material is at least 2.

23. The aerosol-generating article according to claim 20, wherein the additional cellulose comprises cellulose powder and wherein the amount of cellulose powder corresponds to at least 5 percent by weight of the homogenised plant material, on a dry weight basis.

24. The aerosol-generating article according to claim 23, wherein a ratio of cellulose powder to cellulose ether in the homogenised plant material is at least 1.5.

25. The aerosol-generating article according to claim 23, wherein the cellulose powder has at least 95 percent by weight of cellulose.

26. The aerosol-generating article according to claim 23, wherein the cellulose powder has at least 97 percent by weight of cellulose.

27. The aerosol-generating article according to claim 20, wherein the additional cellulose comprises cellulose reinforcement fibers, and wherein an amount of cellulose reinforcement fibers corresponds to at least 3 percent by weight of the homogenised plant material, on a dry weight basis.

28. The aerosol-generating article according to claim 27, wherein a ratio of cellulose reinforcement fibers to cellulose ether in the homogenised plant material is at least 1.

29. The aerosol-generating article according to claim 20, wherein the additional cellulose comprises cellulose powder and cellulose reinforcement fibers, and wherein a ratio of cellulose powder to cellulose reinforcement fibers is at least 1.5.

30. The aerosol-generating article according to claim 20, wherein the cellulose ether comprises carboxymethyl cellulose (CMC).

31. The aerosol-generating article according to claim 20, wherein a total amount of the non-tobacco plant particles or tobacco particles and the additional cellulose is no more than 75 percent by weight of the homogenised plant material, on a dry weight basis.

32. The aerosol-generating article according to claim 20, wherein the homogenised plant material comprises rosemary particles.

33. The aerosol-generating article according to claim 20, wherein the homogenised plant material comprises: between 50 percent by weight and 65 percent by weight of non-tobacco particles on a dry weight basis, and between 15 percent by weight and 25 percent by weight of aerosol former on a dry weight basis.

34. The aerosol-generating article according to claim 21, wherein the homogenised plant material comprises: between 50 percent by weight and 65 percent by weight of tobacco particles on a dry weight basis, and between 15 percent by weight and 25 percent by weight of aerosol former on a dry weight basis.

35. The aerosol-generating article according to claim 20, wherein the homogenised plant material comprises: between 10 percent by weight and 55 percent by weight of non-tobacco particles on a dry weight basis, and between 30 percent by weight and 45 percent by weight of aerosol former on a dry weight basis.

36. The aerosol-generating article according to claim 21, wherein the homogenised plant material comprises: between 10 percent by weight and 55 percent by weight of tobacco particles on a dry weight basis, and between 30 percent by weight and 45 percent by weight of aerosol former on a dry weight basis.

37. The aerosol-generating article according to claim 33, wherein the non-tobacco particles are selected from rosemary particles, star anise particles, ginger particles, clove particles, eucalyptus particles, or combinations thereof.

38. The aerosol-generating article according to claim 32, wherein the aerosol-generating substrate comprises: at least 50 micrograms of betulinic acid per gram of the substrate, on a dry weight basis; at least 20 micrograms of rosmaridiphenol per gram of the substrate, on a dry weight basis; and at least 0.3 micrograms of 12-O-methylcarnosol per gram of the substrate, on a dry weight basis.

39. The aerosol-generating article according to claim 38, wherein upon heating of the aerosol-generating substrate according to Test Method A, an aerosol is generated comprising: at least 30 micrograms of betulinic acid per gram of the substrate, on a dry weight basis; at least 1 microgram of rosmaridiphenol per gram of the substrate, on a dry weight basis; and at least 1 microgram of 12-O-methylcarnosol per gram of the substrate, on a dry weight basis.

Description

[0276] Specific embodiments will be further described, by way of example only, with reference to the accompanying drawings in which:

[0277] FIG. 1 illustrates a first embodiment of a substrate of an aerosol-generating article as described herein;

[0278] FIG. 2 illustrates an aerosol-generating system comprising an aerosol-generating article and an aerosol-generating device comprising an electric heating element;

[0279] FIG. 3 illustrates an aerosol-generating system comprising an aerosol-generating article and an aerosol-generating device comprising a combustible heating element;

[0280] FIGS. 4a and 4b illustrate a second embodiment of a substrate of an aerosol-generating article as described herein;

[0281] FIG. 5 illustrates a third embodiment of a substrate of an aerosol-generating article as described herein;

[0282] FIG. 6 is a cross sectional view of filter 1050 further comprising an aerosol-modifying element, wherein

[0283] FIG. 6a illustrates the aerosol-modifying element in the form of a spherical capsule or bead within a filter plug.

[0284] FIG. 6b illustrates the aerosol-modifying element in the form of a thread within a filter plug.

[0285] FIG. 6c illustrates the aerosol-modifying element in the form of a spherical capsule within a cavity within the filter;

[0286] FIG. 7 is a cross sectional view of a plug of aerosol-generating substrate 1020 further comprising an elongate susceptor element; and

[0287] FIG. 8 illustrates an experimental set-up for collecting aerosol samples to be analysed in order to measure characteristic compounds.

[0288] FIG. 1 illustrates a heated aerosol-generating article 1000 comprising a substrate as described herein. The article 1000 comprises four elements; the aerosol-generating substrate 1020, a hollow cellulose acetate tube 1030, a spacer element 1040, and a mouthpiece filter 1050. These four elements are arranged sequentially and in coaxial alignment and are assembled by a cigarette paper 1060 to form the aerosol-generating article 1000. The article 1000 has a mouth-end 1012, which a user inserts into his or her mouth during use, and a distal end 1013 located at the opposite end of the article to the mouth end 1012. The embodiment of an aerosol-generating article illustrated in FIG. 1 is particularly suitable for use with an electrically-operated aerosol-generating device comprising a heater for heating the aerosol-generating substrate.

[0289] When assembled, the article 1000 is about 45 millimetres in length and has an outer diameter of about 7.2 millimetres and an inner diameter of about 6.9 millimetres.

[0290] The aerosol-generating substrate 1020 comprises a plug formed from a sheet of homogenised plant material comprising rosemary particles, either alone or in combination with tobacco particles.

[0291] A number of examples of a suitable homogenised plant material for forming the aerosol-generating substrate 1020 are shown in Table 1 below (see Samples B to D). The sheet is gathered, crimped and wrapped in a filter paper (not shown) to form the plug. The sheet includes additives, including glycerol as an aerosol former.

[0292] An aerosol-generating article 1000 as illustrated in FIG. 1 is designed to engage with an aerosol-generating device in order to be consumed. Such an aerosol-generating device includes means for heating the aerosol-generating substrate 1020 to a sufficient temperature to form an aerosol. Typically, the aerosol-generating device may comprise a heating element that surrounds the aerosol-generating article 1000 adjacent to the aerosol-generating substrate 1020, or a heating element that is inserted into the aerosol-generating substrate 1020.

[0293] Once engaged with an aerosol-generating device, a user draws on the mouth-end 1012 of the smoking article 1000 and the aerosol-generating substrate 1020 is heated to a temperature of about 375 degrees Celsius. At this temperature, volatile compounds are evolved from the aerosol-generating substrate 1020. These compounds condense to form an aerosol. The aerosol is drawn through the filter 1050 and into the user's mouth.

[0294] FIG. 2 illustrates a portion of an electrically-operated aerosol-generating system 2000 that utilises a heating blade 2100 to heat an aerosol-generating substrate 1020 of an aerosol-generating article 1000. The heating blade is mounted within an aerosol article receiving chamber of an electrically-operated aerosol-generating device 2010. The aerosol-generating device defines a plurality of air holes 2050 for allowing air to flow to the aerosol-generating article 1000. Air flow is indicated by arrows on FIG. 2. The aerosol-generating device comprises a power supply and electronics, which are not illustrated in FIG. 2. The aerosol-generating article 1000 of FIG. 2 is as described in relation to FIG. 1.

[0295] In an alternative configuration shown in FIG. 3, the aerosol-generating system is shown with a combustible heating element. While the article 1000 of FIG. 1 is intended to be consumed in conjunction with an aerosol-generating device, the article 1001 of FIG. 3 comprises a combustible heat source 1080 that may be ignited and transfer heat to the aerosol-generating substrate 1020 to form an inhalable aerosol. The combustible heat source 80 is a charcoal element that is assembled in proximity to the aerosol-generating substrate at a distal end 13 of the rod 11. Elements that are essentially the same as elements in FIG. 1 have been given the same numbering.

[0296] FIGS. 4a and 4b illustrate a second embodiment of a heated aerosol-generating article 4000a, 4000b. The aerosol-generating substrate 4020a, 4020b comprises a first downstream plug 4021 formed from of particulate plant material comprising rosemary particles, and a second upstream plug 4022 formed from particulate plant material comprising primarily tobacco particles. A suitable homogenised plant material for use in the first downstream plug is shown in Table 1 below as one of Samples B to D. A suitable homogenised plant material for use in the second upstream plug is shown in Table 1 below as Sample A. Sample A comprises only tobacco particles and is included for the purposes of comparison only.

[0297] In each of the plugs, the homogenised plant material is in the form of sheets, which are crimped and wrapped in a filter paper (not shown). The sheets both include additives, including glycerol as an aerosol former. In the embodiment shown in FIG. 4a, the plugs are combined in an abutting end to end relationship to form the rod and are of equal length of about 6 mm each. In a more preferred embodiment (not shown), the second plug is preferably longer than the first plug, for example, preferably 2 mm longer, more preferably 3 mm longer, such that the second plug is 7 or 7.5 mm in length while the first plug is 5 or 4.5 mm in length, to provide a desired ratio of tobacco to rosemary particles in the substrate. In FIG. 4b, the cellulose acetate tube support element 1030 has been omitted.

[0298] The article 4000a, 4000b, analogously to the article 1000 in FIG. 1, is particularly suitable for use with the electrically-operated aerosol-generating system 2000 comprising a heater shown in FIG. 2. Elements that are essentially the same elements in FIG. 1 have been given the same numbering. It may be envisaged by the skilled person that a combustible heat source (not shown) may be instead be used with the second embodiment in lieu of the electrical heating element, in a configuration similar to the configuration containing combustible heat source 1080 in article 1001 of FIG. 3.

[0299] FIG. 5 illustrates a third embodiment of a heated aerosol-generating article 5000. The aerosol-generating substrate 5020 comprises a rod formed from a first sheet of homogenised plant material formed of particulate plant material comprising a proportion of rosemary particles, and a second sheet of homogenised plant material comprising primarily cast-leaf tobacco.

[0300] A suitable homogenised plant material for use as the first sheet is shown in Table 1 below as one of Samples B to E. A suitable homogenised plant material for use as the second sheet is shown in Table 1 below as Sample A. Sample A comprises only tobacco particles and is included for the purposes of comparison only.

[0301] The second sheet overlies the first sheet, and the combined sheets have been crimped, gathered and at least partially wrapped in a filter paper (not shown) to form a plug that is part of the rod. Both sheets include additives, including glycerol as an aerosol former. The article 5000, analogously to the article 1000 in FIG. 1, is particularly suitable for use with the electrically-operated aerosol-generating system 2000 comprising a heater shown in FIG. 2. Elements that are essentially the same elements in FIG. 1 have been given the same numbering. It may be envisaged by the skilled person that a combustible heat source (not shown) may be instead be used with the third embodiment in lieu of the electrical heating element, in a configuration similar to the configuration containing combustible heat source 1080 in article 1001 of FIG. 3.

[0302] FIG. 6 is a cross sectional view of filter 1050 further comprising an aerosol-modifying element. In FIG. 6a, the filter 1050 further comprises an aerosol-modifying element in the form of a spherical capsule or bead 605.

[0303] In the embodiment of FIG. 6a, the capsule or bead 605 is embedded in the filter segment 601 and is surrounded on all sides by the filter material 603. In this embodiment, the capsule comprises an outer shell and an inner core, and the inner core contains a liquid flavourant. The liquid flavourant is for flavouring aerosol during use of the aerosol-generating article provided with the filter. The capsule 605 releases at least a portion of the liquid flavourant when the filter is subjected to external force, for example by squeezing by a consumer. In the embodiment shown, the capsule is generally spherical, with a substantially continuous outer shell containing the liquid flavourant.

[0304] In the embodiment of FIG. 6b, the filter segment 601 comprises a plug of filter material 603 and a central flavour-bearing thread 607 that extends axially through the plug of filter material 603 parallel to the longitudinal axis of the filter 1050. The central flavour-bearing thread 607 is of substantially the same length as the plug of filter material 603, so that the ends of the central flavour-bearing thread 607 are visible at the ends of the filter segment 601. In FIG. 6b, filter material 603 is cellulose acetate tow. The central flavour-bearing thread 607 is formed from twisted filter plug wrap and loaded with an aerosol-modifying agent.

[0305] In the embodiment of FIG. 6c, the filter segment 601 comprises more than one plug of filter material 603, 603′. Preferably, the plugs of filter material 603, 603′ are formed from cellulose acetate, such that they are able to filter the aerosol provided by the aerosol generating article. A wrapper 609 is wrapped around and connects filter plugs 603, 603′. Inside a cavity 611 is a capsule 605 comprising an outer shell and an inner core, and the inner core contains a liquid flavourant. The capsule is otherwise similar to the embodiment of FIG. 6a.

[0306] FIG. 7 is a cross sectional view of aerosol-generating substrate 1020 further comprising an elongate susceptor strip 705. The aerosol-generating substrate 1020 comprises a plug 703 formed from a sheet of homogenised plant material comprising tobacco particles and rosemary particles. The elongate susceptor strip 705 is embedded within the plug 703 and extends in a longitudinal direction between the upstream and downstream ends of the plug 703. During use, the elongate susceptor strip 705 heats the homogenised plant material by means of induction heating, as described above.

EXAMPLE 1

[0307] Different samples of homogenised plant material for use in an aerosol-generating substrate according to the invention, as described above with reference to the figures, were prepared from aqueous slurries having compositions shown Table 1. Samples B to E comprise rosemary particles, in accordance with a preferred embodiment of the invention. In Samples B to D, the rosemary particles are combined with tobacco particles. Sample A comprises tobacco particles only. Sample E comprises rosemary particles only.

[0308] The particulate plant material in all samples A to E accounted for 65 percent of the dry weight of the homogenised plant material, with glycerol, CMC, cellulose powder and cellulose reinforcement fibers accounting for the remaining 35 percent of the dry weight of homogenised plant material.

[0309] In the table below, % DWB refers to the “dry weight base,” in this case, the percent by weight calculated relative to the dry weight of the homogenised plant material. The rosemary powder was formed from Rosmarinus Officinalis leaves from Spain, which was ground to a final D95=133 microns by triple impact milling. The rosemary powder was sieved to remove particles above 200 microns. In more detail, Sample E was prepared from an aqueous slurry containing: [0310] Rosemary: 17.78 kg/100 kg of slurry [0311] Glycerol: 4.50 kg/100 kg of slurry [0312] CMC: 1.25 kg/100 kg of slurry [0313] Cellulose powder: 2.50 kg/100 kg of slurry [0314] Cellulose fibres: 1.00 kg/100 kg of slurry [0315] Water: 72.97 kg/100 kg of slurry.

TABLE-US-00001 TABLE 1 Dry content of slurries Glycerol CMC Cellulose Cellulose Sam- Rosemary Tobacco (% (% powder fibers ple (% DWB) (% DWB) DWB) DWB) (% DWB) (% DWB) A 0 65 17 5 9 4 B 1 64 17 5 9 4 C 6.5 58.5 17 5 9 4 D 13 52 17 5 9 4 E 65 0 17 5 9 4

[0316] The slurries were cast using a casting bar (0.6 mm) on a glass plate, dried in an oven at 140 degrees Celsius and then dried in a second oven at 135 degrees Celsius.

[0317] For each of the samples A to E of homogenised plant material, a plug was produced from a single continuous sheet of the homogenised plant material, the sheets each having widths of between 100 mm to 125 mm. The individual sheets had a thickness of about 220 microns and a grammage of about 135 g/m.sup.2. The cut width of each sheet was adapted based on the thickness of each sheet to produce rods of comparable volume. The sheets were crimped to a height of 165 microns to 170 microns, and rolled into plugs having a length of about 12 mm and diameters of about 7 mm, circumscribed by a paper wrapper.

[0318] For each of the plugs, an aerosol-generating article having an overall length of about 45 mm was formed having a structure as shown in FIG. 3 comprising, from the downstream end: a mouth end cellulose acetate filter (about 7 mm long), an aerosol spacer comprising a crimped sheet of polylactic acid polymer (about 18 mm long), a hollow acetate tube (about 8 mm long) and the plug of aerosol-generating substrate.

[0319] For Sample E of homogenised plant material, for which rosemary particles make up 100 percent of the plant particles, the characteristic compounds of the rosemary were extracted from the plug of homogenised plant material using methanol as detailed above. The extract was analysed as described above to confirm the presence of the characteristic compounds and to measure the amounts of the characteristic compounds. The results of this analysis are shown below in Table 2, wherein the amounts indicated correspond to the amount per aerosol-generating article, wherein the aerosol-generating substrate of the aerosol-generating article contained 178 mg of the Sample E of homogenised plant material.

[0320] For the purposes of comparison, the amounts of the characteristic compounds present in the particulate plant material (rosemary particles) used to form Sample E are also shown. For the particulate material, the amounts indicated correspond to the amount of the characteristic compound in a sample of particulate plant material having a weight corresponding to the total weight of the particulate plant material in the aerosol-generating article containing 178 mg of Sample E.

TABLE-US-00002 TABLE 2 Amount of rosemary-specific compounds in the particulate plant material and in the aerosol-generating substrate Amount in the particulate Amount in the aerosol- Characteristic plant material generating substrate Compound (micrograms per article) (micrograms per article) Betulinic acid 717 608 Rosmaridiphenol 243 290 12-O- 5.6 3.9 methylcarnosol

[0321] For each of the samples B to D comprising a proportion of rosemary particles, the amount of the characteristic compounds can be estimated based on the values in Table 2 by assuming that the amount is present in proportion to the weight of the rosemary particles.

[0322] Mainstream aerosols of the aerosol-generating articles incorporating aerosol-generating substrates formed from Samples A to E of homogenised plant material were generated in accordance with Test Method A, as defined above. For each sample, the aerosol that was produced was trapped and analysed.

[0323] As described in detail above, according to Test Method A, the aerosol-generating articles were tested using the commercially available IQOS® heat-not-burn device tobacco heating system 2.2 holder (THS2.2 holder) from Philip Morris Products SA. The aerosol-generating articles were heated under a Health Canada machine-smoking regimen over 30 puffs with a puff volume of 55 ml, puff duration of 2 seconds and a puff interval of 30 seconds (as described in ISO/TR 19478-1:2014).

[0324] The aerosol generated during the smoking test was collected on a Cambridge filter pad and extracted with a liquid solvent. FIG. 10 shows suitable apparatus for generating and collecting the aerosol from the aerosol-generating articles.

[0325] Aerosol-generating device 111 shown in FIG. 10 is a commercially available tobacco heating device (IQOS). The contents of the mainstream aerosol generated during the Health Canada smoking test as detailed above were collected in aerosol collection chamber 113 on aerosol collection line 120. Glass fiber filter pad 140 is a 44 mm Cambridge glass fiber filter pad (CFP) in accordance with ISO 4387 and ISO 3308.

For LC-HRAM-MS Analysis:

[0326] Extraction solvent 170, 170a, which in this case is methanol and internal standard (ISTD) solution, is present at a volume of 10 mL in each micro-impinger 160, 160a. The cold baths 161, 161a each contain a dry ice-isopropyl ether to maintain the micro-impingers 160, 160a each at approximately −60° C. The gas-vapour phase is trapped in the extraction solvent 170, 170a as the aerosol bubbles through micro-impingers 160, 160a. The combined solutions from the two micro-impingers are isolated as impinger-trapped gas-vapor phase solution 180 in step 181.

[0327] The CFP and the impinger-trapped gas-vapor phase solution 180 are combined in a clean Pyrex® tube in step 190. In step 200, the total particulate matter is extracted from the CFP using the impinger-trapped gas-vapor phase solution 180 (which contains methanol as a solvent) by thoroughly shaking (disintegrating the CFP), vortexing for 5 min and finally centrifuging (4500 g, 5 min, 10° C.). Aliquots (300 μL) of the reconstituted whole aerosol extract 220 were transferred into a silanized chromatographic vial and diluted with methanol (700 μL), since the extraction solvent 170, 170a already comprised internal standard (ISTD) solution. The vials were closed and mixed for 5 minutes using an Eppendorf ThermoMixer (5° C.; 2000 rpm).

[0328] Aliquots (1.5 μL) of the diluted extracts were injected and analyzed by LC-HRAM-MS in both full scan mode and data-dependent fragmentation mode for compound identification.

For GC×GC-TOFMS Analysis:

[0329] As discussed above, when samples for GC×GC-TOFMS experiments are prepared, different solvents are suitable for extracting and analysing polar compounds, non-polar compounds and volatile compounds separated from whole aerosol. The experimental set-up is identical to that described with respect to sample collection for LC-HRAM-MS, with the exceptions indicated below.

[0330] Nonpolar & Polar

[0331] Extraction solvent 171,171a, is present at a volume of 10 mL and is an 80:20 v/v mixture of dichlormethane and methanol, also containing retention-index marker (RIM) compounds and stable isotopically labeled internal standards (ISTD). The cold baths 162, 162a each contain a dry ice-isopropanol mixture to maintain the micro-impingers 160, 160a each at approximately −78° C. The gas-vapor phase is trapped in the extraction solvent 171, 171a as the aerosol bubbles through micro-impingers 160, 160a. The combined solutions from the two micro-impingers are isolated as impinger-trapped gas-vapor phase solution 210 in step 182.

[0332] Nonpolar

[0333] The CFP and the impinger-trapped gas-vapor phase solution 210 are combined in a clean Pyrex® tube in step 190. In step 200, the total particulate matter is extracted from the CFP using the impinger-trapped gas-vapor phase solution 210 (which contains dichloromethane and methanol as a solvent) by thoroughly shaking (disintegrating the CFP), vortexing for 5 min and finally centrifuging (4500 g, 5 min, 10° C.) to isolate the polar and non-polar components of the whole aerosol extract 230.

[0334] In step 250, an 10 mL aliquot 240 of the whole aerosol extract 230 was taken. In step 260, a 10 mL aliquot of water is added, and the entire sample is shaken and centrifuged. The non-polar fraction 270 was separated, dried with sodium sulfate and analysed by GC×GC-TOFMS in full scan mode.

[0335] Polar

[0336] ISTD and RIM compounds were added to polar fraction 280, which was then directly analysed by GC×GC-TOFMS in full scan mode.

[0337] Each smoking replicate (n=3) comprises the accumulated trapped and reconstituted non-polar fraction 270 and polar fraction 280 for each sample

[0338] Volatile Components

[0339] Whole aerosol was trapped using two micro-impingers 160, 160a in series. Extraction solvent 172, 172a, which in this case is N,N-dimethylformamide (DMF) containing retention-index marker (RIM) compounds and stable isotopically labeled internal standards (ISTD), is present at a volume of 10 mL in each micro-impinger 160, 160a. The cold baths 161, 161a each contain a dry ice-isopropyl ether to maintain the micro-impingers 160, 160a each at approximately −60° C. The gas-vapor phase is trapped in the extraction solvent 170, 170a as the aerosol bubbles through micro-impingers 160, 160a. The combined solutions from the two micro-impingers are isolated as a volatile-containing phase 211 in step 183. The volatile-containing phase 211 is analysed separately from the other phases and injected directly into the GC×GC-TOFMS using cool-on-column injection without further preparation.

[0340] Table 3 below shows the levels of the characteristic compounds from the rosemary particles in the aerosol generated from an aerosol-generating article incorporating Sample E of homogenised plant material, including rosemary particles only. For the purposes of comparison, Table 3 also shows the levels of the characteristic compounds in the aerosol generated from an aerosol-generating article incorporating Sample A of homogenised plant material, including tobacco particles only (and therefore not in accordance with the invention).

TABLE-US-00003 TABLE 3 Content of characteristic compounds in aerosol Sample A Sample E Sample E Sample E (micrograms (micrograms (micrograms (micrograms Compound per article) per gram) per 55 ml puff) per article) Betulinic acid 0 2275 33.75 405 Rosmaridiphenol 0 109 1.62 19.4 12-O- 0 118.5 0.68 21.1 methylcarnosol

[0341] For example, in an aerosol generated from Sample E, relatively high levels of the characteristic compounds would be measured. The ratio of betulinic acid to rosmaridiphenol would typically be greater than 20:1. Measured levels of the characteristic compounds within the ranges above would be indicative of the presence of rosemary particles in the sample and a composition of the homogenised sheet as defined above. In contrast, for the tobacco only Sample A, which contained substantially no rosemary particles, the levels of the characteristic compounds would be found to be at or close to zero.

[0342] For each of the samples B to D comprising a proportion of rosemary particles, the amount of the characteristic compounds in the aerosol can be estimated based on the values in Table 3 by assuming that the amount is present in proportion to the weight of the rosemary particles in the aerosol-generating substrate from which the aerosol is generated.

[0343] The aerosol produced by Sample E containing 65 percent by weight rosemary powder was also found to result in reduced levels of several undesired aerosol constituents when compared to the level of the aerosol in Sample A produced using 100 percent by weight tobacco based on the dry weight of the particulate plant material.

EXAMPLE 2

[0344] Sheets of homogenised plant material according to the invention were formed using the compositions shown as Recipe 1 and Recipe 2 below in Table 4. For the purposes of comparison, a third sheet of homogenised plant material using an alternative binder (and therefore not according to the invention) was formed using the composition shown as Recipe 3 below in Table 4. All of the sheets incorporated a relatively high level of rosemary particles and were formed using a cast leaf method as set out above in Example 1.

TABLE-US-00004 TABLE 4 Dry content of slurries Rosemary Guar CMC Cellulose Cellulose Sam- powder Glycerol (% (% powder fibers ple (% DWB) (% DWB) DWB) DWB) (% DWB) (% DWB) 1 57 25 0 5 10 3 2 54 35 0 5 0 6 3 75 18 3 0 0 4

[0345] The cast leaf formed from Samples 1 and 2 in accordance with the invention were both found to be homogenous in texture with a relatively uniform thickness and high tensile strength. The cast leaf could be readily removed from the casting plate and formed into a rod of aerosol-generating substrate. In contrast, the cast leaf formed from Sample 3, using a known binder instead of the combination of CMC and cellulose, was found to be porous and fragile with virtually no tensile strength. The cast leaf could not be readily detached from the casting plate and was found to fragment such that it could not be formed into a rod of aerosol-generating substrate. This example demonstrates that the use of the combination of CMC and additional cellulose in place of the guar gum binder provides a significantly improved sheet of homogenised plant material, with a greatly improved tensile strength and homogeneity.

[0346] The cast leaf formed from Sample 2 has a relatively high level of aerosol former (35 percent by weight) and is particularly suitable for use in forming the aerosol-generating substrate of an aerosol-generating article which is intended to be heated to a temperature of below 275 degrees Celsius.

[0347] When heated to a temperature of around 265 degrees Celsius, an aerosol-generating substrate produced from the cast leaf formed from Sample 2 was found to provide a significantly improved aerosol delivery compared to the cast leaf from Sample 3. In particular, the aerosol delivery was improved to a greater extent than would be expected based on the level of aerosol former alone. This demonstrates the improvement in aerosol delivery provided by incorporating the CMC binder in place of the guar gum.

EXAMPLE 3

[0348] The following homogenised plant materials according to the invention were produced using a casting leaf method as described above for Example 1, each with a different type of non-tobacco plant material. For each plant material, the composition shown below in Table 5 was used:

TABLE-US-00005 TABLE 5 Composition of homogenised plant materials Component Amount (% DWB) Plant powder 54 CMC 5 Cellulose fibers 6 Glycerol 35

[0349] The properties of the resultant homogenised plant materials are shown in Table 6 below.

TABLE-US-00006 TABLE 6 Properties of homogenised plant materials Grammage Thickness Plant powder (g/m2) (microns) Manufacturing observations Star anise 209 409 Good sheet quality. High thickness Ginger 207 221 Good sheet quality Clove 209 215 Good sheet quality Eucalyptus 197 218 Good sheet quality Rosemary 135 223 Good sheet quality

[0350] In each case, the resultant homogenised plant material was found to have an acceptable thickness and tensile strength to enable it to be incorporated into an aerosol-generating article.