CLOVE-CONTAINING AEROSOL-GENERATING SUBSTRATE

Abstract

An aerosol-generating article is provided, including an aerosol-generating substrate including homogenised plant material formed of particulate plant material, the particulate plant material including between 10 percent and 40 percent by weight clove particles and between 60 percent and 90 percent by weight tobacco particles, based on dry weight of the particulate plant material, and the homogenised plant material further including an aerosol former and a binder. An aerosol-generating system is also provided, including an aerosol-generating device including a heating element; and the aerosol-generating article. A method is also provided for making one or more sheets of the homogenised plant material of aerosol-generating substrate of the aerosol-generating article.

Claims

1.-15. (canceled)

16. An aerosol-generating article, comprising: an aerosol-generating substrate comprising homogenised plant material formed of particulate plant material, wherein the particulate plant material comprises between 10 percent and 40 percent by weight clove particles and between 60 percent and 90 percent by weight tobacco particles, based on dry weight of the particulate plant material, and wherein the homogenised plant material further comprises an aerosol former and a binder.

17. The aerosol-generating article according to claim 16, wherein the particulate plant material has a D90 value of from greater than or equal to 20 microns to a D90 value of from less than or equal to 300 microns.

18. The aerosol-generating article according to claim 16, wherein the homogenised plant material further comprises particulate plant material agglomerated by the binder.

19. The aerosol-generating article according to claim 16, wherein the aerosol-generating substrate further comprises one or more sheets, a plurality of strands, or a plurality of shreds of the homogenised plant material.

20. The aerosol-generating article according to claim 16, wherein the aerosol-generating substrate further comprises one or more sheets, and the one or more sheets each individually comprise one or more of: a thickness of between 100 μm and 600 μm, or a grammage of between about 100 g/m.sup.2 and about 300 g/m.sup.2.

21. The aerosol-generating article according to claim 19, wherein the aerosol-generating substrate further comprises one or more sheets, and the one or more sheets each individually comprise one or more of: a tensile strength at peak in a cross direction of from 50 N/m to 400 N/m, or a tensile strength at peak in a machine direction of from 100 N/m to 800 N/m.

22. The aerosol-generating article according to claim 16, wherein the homogenised plant material further comprises a first homogenised plant material and a second homogenised plant material, wherein the first homogenised plant material is formed of a first particulate plant material comprising between at least 50 percent and 100 percent by weight clove particles, based on dry weight of the first particulate plant material, and wherein the second homogenised plant material is formed of a second particulate plant material comprising between at least 50 percent and 100 percent by weight tobacco particles, based on dry weight of the second particulate plant material.

23. The aerosol-generating article according to claim 22, wherein the first homogenised plant material is in a form of one or more sheets and the second homogenised plant material is in a form of one or more sheets.

24. The aerosol-generating article according to claim 22, further comprising a first plug and a second plug, wherein the first homogenised plant material is located in the first plug and the second homogenised plant material is located in the second plug.

25. The aerosol-generating article according to claim 22, wherein the first homogenised plant material is in a form of a first sheet, and the second homogenised plant material is in a form of a second sheet, and wherein the second sheet at least partially overlies the first sheet.

26. The aerosol-generating article according to claim 25, wherein the second sheet of the second homogenised plant material overlies the first sheet of the first homogenised plant material, and wherein a combination of the first and the second sheets are gathered to form a plug of the aerosol-generating substrate.

27. The aerosol-generating article according to claim 16, further comprising an aerosol-modifying element.

28. An aerosol-generating system, comprising: an aerosol-generating device comprising a heating element; and an aerosol-generating article according to claim 16.

29. A method of making one or more sheets of the homogenised plant material of aerosol-generating substrate of the aerosol-generating article according to claim 16, the method comprising the steps of: forming a mixture comprising particulate plant material, water, binder, and an aerosol former, wherein the particulate plant material contains between 10 percent and 60 percent by weight clove particles and between 40 percent and 90 percent by weight tobacco particles, based on dry weight of the particulate plant material; forming the one or more sheets from the mixture comprising particulate plant material; and drying the one or more sheets.

Description

[0112] Specific embodiments will be further described, by way of example only, with reference to the accompanying drawings in which:

[0113] FIG. 1 illustrates a first embodiment of a substrate of an aerosol-generating article as described herein;

[0114] FIG. 2 illustrates an aerosol-generating system comprising an aerosol-generating article and an aerosol-generating device comprising an electric heating element;

[0115] FIG. 3 illustrates an aerosol-generating system comprising an aerosol-generating article and an aerosol-generating device comprising a combustible heating element;

[0116] FIGS. 4a and 4b illustrate a second embodiment of a substrate of an aerosol-generating article as described herein; and

[0117] FIG. 5 illustrates a third embodiment of a substrate of an aerosol-generating article as described herein.

[0118] FIG. 6 is a cross sectional view of filter 1050 further comprising an aerosol-modifying element, wherein

[0119] FIG. 6a illustrates the aerosol-modifying element in the form of a spherical capsule or bead within a filter plug.

[0120] FIG. 6b illustrates the aerosol-modifying element in the form of a thread within a filter plug.

[0121] FIG. 6c illustrates the aerosol-modifying element in the form of a spherical capsule within a cavity within the filter.

[0122] FIG. 7 is a cross sectional view of a plug of aerosol-generating substrate 1020 further comprising an aerosol-modifying element in the form of a bead.

[0123] FIG. 8 illustrates the measuring principle and the relevant dimensions of the test specimen before and during stretching in the Dry Tensile Strength test described herein.

[0124] FIG. 9 illustrates a typical force/elongation curve obtained for a single test specimen and the relevant formulae for calculating the tensile strength and stretch at break.

[0125] 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.

[0126] 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.

[0127] The aerosol-generating substrate 1020 comprises a plug formed from a sheet of homogenised plant material formed comprising tobacco particles and clove particles. The sheet is gathered, crimped and wrapped in a filter paper (not shown) to form the plug. The sheet includes additives, including glycerine as an aerosol-forming additive.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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 primarily clove particles, and a second upstream plug 4022 formed from particulate plant material comprising primarily tobacco particles. 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 glycerine as an aerosol-forming additive. 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 clove particles in the substrate. In FIG. 4b, the cellulose acetate tube support element 1030 has been omitted.

[0133] 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.

[0134] 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 primarily clove particles, and a second sheet of homogenised plant material comprising primarily cast-leaf tobacco. 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 glycerine as an aerosol-forming additive. 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] FIG. 7 is a cross sectional view of aerosol-generating substrate 1020 further comprising an aerosol-modifying element in the form of a bead 705. The aerosol-generating substrate 1020 comprises a plug 703 formed from a sheet of homogenised plant material comprising tobacco particles and clove particles. The flavour delivery material in the bead 705 incorporates a flavourant which is released upon heating the material to a temperature above 220° C. The flavourant is therefore released into the aerosol as a portion of the plug is heated during use.

Test Methods

Dry Tensile Strength Test

[0140] The Dry Tensile Strength Test (ISO 1924-2) measures the tensile strength of a sheet of homogenised plant material conditioned under dry conditions. Tensile strength is a measure of the maximum tensile force per unit width that a sheet will withstand before breaking under the conditions defined in this standard.
Material and equipment: [0141] Universal Tensile/Compression Testing Machine, Instron 5566, or equivalent [0142] Tension load cell of 100 Newtons, Instron, or equivalent [0143] Two pneumatic action grips [0144] A steel gauge block of 180±0.25 millimetres length (width: ˜10 millimetres, thickness: ˜3 millimetres) [0145] Double-bladed strip cutter, size 15±0.05ט250 millimetres, Adamel Lhomargy, or equivalent [0146] Scalpel [0147] Computer running acquisition software, Merlin, or equivalent [0148] Compressed air

Sample Preparation:

[0149] Condition the sheet of homogenised plant material for at least 24 hours at 22±2 degrees Celsius and 60±5% relative humidity before testing. [0150] Cut machine direction or cross direction sample to the following dimensions: ˜250×15±0.1 millimetres with the double-bladed strip cutter. The edges of the test pieces must be cut cleanly—do not cut more than three test specimens at the same time

Setting Up of the Instrument:

[0151] Install the tension load cell of 100 Newtons [0152] Switch on the Universal Tensile/Compression Testing Machine and the computer [0153] Select the measurement method predefined in the software (test speed set to 8 millimetres per minute) [0154] Calibrate the tension load cell [0155] Install the pneumatic action grips [0156] Adjust the test distance between the pneumatic action grips to 180±0.5 millimetres by means of the steel gauge block [0157] Set the distance and the force to zero

Testing Procedure:

[0158] Place the test specimen straight and centrally between the grips, avoid touching the area to be tested with fingers. [0159] Close the upper grip and let the paper strip hang in the opened lower grip. [0160] Set the force to zero. [0161] Pull down lightly on the paper strip, and then close the lower grip by maintaining the force on the test specimen—the starting force must be between 0.05 and 0.20 Newtons. [0162] Start the measurement. While the grip is moving upward, a gradually increasing force is applied until the test specimen breaks. [0163] Repeat the same procedure with the remaining test specimens.
Note: The result is valid when the test specimen breaks at a distance of more than 10 millimetres from the grips. If it is not the case, reject this result and perform an additional measurement.

[0164] FIG. 8 illustrates the measuring principle and the relevant dimensions of the test specimen before the test and when stretched during the test.

[0165] FIG. 9 illustrates a typical force/elongation curve obtained for a single test specimen and the relevant formulae for calculating the tensile strength and stretch at break.

EXAMPLE 1

[0166] Rods having a diameter of about 7 mm, comprising a plug of aerosol-generating substrate and circumscribed by a paper wrapper were prepared. The plug having a length of about 12 mm comprises a crimped sheet of homogenised plant material formed of particulate plant material. The rods having an overall length of about 45 mm also comprise at the mouth end, a cellulose acetate filter (about 7 mm long), followed by a crimped sheet of polylactic acid (about 18 mm long) and then a hollow acetate tube (about 8 mm long) which is adjacent to the plug of aerosol-generating substrate.

[0167] Aqueous slurries were prepared with the following content in accordance with Table 1. The particulate plant material in all samples accounted for 76.1% of the dry weight of the homogenised plant material, with glycerin, guar gum and cellulose fibers accounting for the remaining 23.9% of the dry weight of homogenised plant material. 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 D90 of the particulate plant material was 120 μm.

TABLE-US-00001 TABLE 1 Dry content of slurries Clove Kasturi Flue-cured Guar Cellulose powder tobacco tobacco Glycerin Gum fibers Sample (% DWB) (% DWB) (% DWB) (% DWB) (% DWB) (% DWB) A 22.83 35.77 17.50 17.7 2.3 3.9 B 30.44 30.44 15.22 17.7 2.3 3.9 C 38.05 25.11 12.94 17.7 2.3 3.9 D 30.44 15.22 30.44 17.7 2.3 3.9

[0168] In this example, two types of tobacco were used, Kasturi and flue-cured tobacco respectively. The clove powder has a eugenol content of about 110 mg/g. The slurries were casted using a casting bar (0.6 mm) on a glass plate, dried in an oven at 140° C. for 7 minutes, and then dried in a second oven at 120° C. for 30 seconds.

[0169] Each plug was produced from a single continuous sheet of homogenised plant material, the sheets each having widths of between 100 mm to 125 mm. The individual sheets had thickness of about 220 μm and a grammage of about 200 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 μm to 170 μm, and rolled into plugs having a length of 12 mm and diameters of between 6.9 mm and 7.2 mm, circumscribed by a paper wrapper. The plug was inserted manually into a pre-assembled rod next to the hollow acetate tube further from the mouth end. Regular tipping paper was applied.

[0170] The aerosol-generating articles were tested by product developers with experience in smoking Kretek cigarettes using the commercially available iQOS® heat-not-burn device from Philip Morris International. The results of the sensorial assessment are given in Table 2 below.

TABLE-US-00002 TABLE 2 Sensorial assessment Sample A B C D Ranking 4 1 3 2 (panelist 1) Ranking 4 3 1 2 (panelist 2) Comments Good smoke volume Slightly higher clove Lower smoke volume Highest clove taste & (panelist 1) Medium clove aroma aroma Higher bright-nutty note aroma Medium dark tobacco Slightly higher bright- Medium dark tobacco Medium smoke volume Imbalanced nutty note High impact Imbalance between High impact Medium dark tobacco tobacco & clove Balanced High impact High impact Comments Slight clove spicy note Pronounced clove Less sweet Very smooth (panelist 2) More pronounced clove taste, but not so much Most balanced Most Kretek-like aroma spicy sensation Some biting/numbing No harshness Quite stable A bit too sweet sensation Creamy direction Herbal direction Salivating Salivating Salivating Very low harshness Very low harshness No harshness
A clove inclusion of about 30% dry weight base was preferred by both panelists, while about 23% in Sample A was found to provide insufficient clove aroma. About 30% dry weight base of clove in the substrate corresponds to about 40% by dry weight of clove in the particulate plant material, the particulate plant material containing clove powder and tobacco powder.

[0171] The results from the sensorial assessment in Table 2 demonstrate that the inclusion of clove particles in the sheet of homogenised plant material enables a sensorial experience that is close to that of a conventional Kretek cigarette.

EXAMPLE 2

[0172] Rods having a diameter of about 7 mm, comprising a plug of aerosol-generating substrate and circumscribed by a paper wrapper were prepared as described in Example 1. The plug having a length of about 12 mm comprises a crimped sheet of homogenised plant material formed of particulate plant material. The rods having an overall length of about 45 mm also comprise at the mouth end, a cellulose acetate filter (about 7 mm long), followed by a crimped sheet of polylactic acid (about 18 mm long) and then a hollow acetate tube (about 8 mm long) which is adjacent to the plug of aerosol-generating substrate.

[0173] Comparative sample E is a control plug produced from a continuous sheet of homogenised tobacco material and does not contain clove. This sheet was produced by a casting process from an aqueous slurry (25% dry weight), the sheet having a width of 132 mm, a thickness of 215 μm, a grammage of 202 g/m.sup.2 and a moisture content of between 11 and 12%. The continuous sheet comprised about 76.1% dry weight base of tobacco material, 17.7% by dry weight base of glycerine, 2.3% by dry weight base of guar gum, and 3.9% by dry weight base of cellulose fibers, based on the dry weight of the homogenised plant material. The tobacco powder was a blend consisting of 66.6% by weight flue-cured tobacco and 33.3% by weight Indonesian Kasturi tobacco, with a nicotine content of 3.8% by dry weight base.

[0174] A mixture was prepared using 45% dry weight base tobacco powder and 30% dry weight base clove powder (both based on the dry weight of the homogenised plant material). The tobacco particles had a D95 value equal to 55 μm, while the clove particles had a D90 value equal to 60 μm. The mixture was used in a casting process to produce a continuous sheet of homogenised plant material to produce the rod in Sample F. The tobacco powder had the same tobacco blend and nicotine content as Comparative sample E. The continuous sheet also comprised about 17.7% by dry weight base of glycerine, 2.3% by dry weight base of guar gum, and 3.9% by dry weight base of cellulose fibers, based on the dry weight of the homogenised plant material. The continuous sheet was produced by a casting process from an aqueous slurry, the sheet having a width of 125 mm and a thickness of 270 μm. The width of the sheet was reduced to achieve a similar volume as the control plug in Comparative sample E, due to the increase in thickness of the sheet.

[0175] The aerosol-generating articles were tested using the commercially available iQOS® heat-not-burn device from Philip Morris International.

[0176] The content of various compounds in aerosol per group of five puffs of the aerosol-generating articles of Comparative sample E and Sample F is measured under a Health Canada smoking regime over 30 puffs with a puff volume of 55 ml, puff duration of 2 seconds and a puff interval of 30 seconds. See ISO/TR 19478. Each group of five puffs is collected on a Cambridge filter pad and then extracted with a liquid solvent. The resulting liquid is analysed by gas chromatography to determine the content of the aerosol. Three replicates were performed and a standard deviation is reported for each value. The results are shown in Table 3.

TABLE-US-00003 TABLE 3 Content of Various Compounds in Aerosol Aerosol Constituent Comparative Sample E Sample F Reduction (%) Acrylamide (μg/cig) 1.93 ± 0.05 1.13 ± 0.03 42 Catechol (μg/cig) 13.2 ± 0.91 9.79 ± 0.68 26 Hydroquinone (μg/cig) 5.87 ± 0.31 4.39 ± 0.35 25 Phenol (μg/cig) 1.65 ± 0.10 1.34 ± 0.22 19 Isoprene (μg/cig) 1.94 ± 0.40 1.38 ± 0.08 29 Acetaldehyde (μg/cig)  200 ± 2.96  159 ± 13.0 20 Nicotine (μg/cig) 1.86 ± 0.04 1.13 ± 0.05 — Glycerine (μg/cig) 5.23 ± 0.08 4.99 ± 0.41 — Eugenol (μg/cig) — 0.33

[0177] As shown in Table 3, the aerosol produced by Sample F containing clove powder results in reduced levels of acrylamide, catechol, hydroquinone, phenol, isoprene and acetaldehyde when compared to the level of the aerosol in Comparative sample E produced using the same tobacco blend but without adding clove. This observed reduction of phenol and catechol is particularly unexpected since a previous study comparing the aerosol chemistry of a conventional tobacco cigarette with that of Kretek cigarettes containing 31 to 33% clove by weight found higher levels of these compounds in the clove-containing cigarettes (Piade et al., Regul. Toxicol. Pharmacol. 2014, 70 S15-S25).

EXAMPLE 3

Comparative Example

[0178] A homogenised particulate tobacco sheet was prepared according to a conventional cast leaf process with the following composition:

[0179] 100% by weight of the particulate plant material as particulate tobacco material. 76.1% by weight tobacco particles, 2.3% by weight guar gum, 17.7% by weight glycerine and 3.9% by weight cellulosic fibers, based on dry weight of the substrate.

[0180] The dry tobacco material was fed to a grinder where it was dry ground and screened and subsequently contacted with an aqueous medium including guar as the binder in a high-shear mixer to form a tobacco slurry. The tobacco slurry was then cast onto a moving endless belt. The cast slurry was subsequently passed through a drying assembly to remove moisture so as to form a cast leaf sheet. Finally, the sheet was removed from the belt with a doctor blade.

[0181] The 100% tobacco cast leaf sheet obtained had the properties given for Sample No. 1 in Table 4 below.

EXAMPLES

[0182] A homogenised particulate plant material sheet was prepared from clove particles or clove particles and tobacco particles according to a cast leaf process in accordance with the invention. The samples had the following compositions:

[0183] 76.1% by weight particulate plant material, 2.3% by weight guar gum, 17.7% by weight glycerine and 3.9% by weight cellulosic fibers, based on dry weight of the substrate.

[0184] The percentages by weight of the clove particles based on the dry weight of the particulate plant material are given in Table 4 below. The balance of the weight of particulate plant material was made up by different blends of particulate tobacco.

[0185] The particulate plant material was fed to a grinder where it was dry ground into particles and screened and subsequently contacted with an aqueous medium including guar as the binder in a high-shear mixer to form a slurry. The slurry was then cast onto a moving endless belt. The cast slurry was subsequently passed through a drying assembly to remove moisture so as to form a sheet. Finally, the sheet was removed from the belt with a doctor blade.

[0186] The sheets obtained had the properties given for Sample Nos. 2 through 8 in Table 4. To normalize the tensile strength values (that is, Fmax and Δ I in both directions), the actual tensile strength values and the corresponding thickness are used to calculate the tensile strength values for a sheet that is 215 micrometers thick. The following formula is used:

Normalized value=actual value*215/actual thickness

TABLE-US-00004 TABLE 4 Physical properties of sheets CD MD F.sub.at peak CD F.sub.at peak MD Sample Grammage Thickness Density (N/m) ΔI.sub.at peak (N/m) ΔI.sub.at peak No. (g/cm.sup.2) (μm) (g/cm.sup.3) Values normalised to a thickness of 215 μm 1 Comparative Sample - 175.2 200.9 0.87 144 0.015 203 0.025 100% tobacco 2 100% clove 200.2 261.8 0.77 279 0.022 596 0.049 3 Tobacco blend 1 with 204.6 235.4 0.87 176 0.019 332 0.043 30% clove 4 Tobacco blend 1 with 202.2 245.0 0.83 187 0.020 395 0.044 40% clove 5 Tobacco blend 1 with 203.7 249.7 0.82 214 0.019 355 0.040 50% clove 6 Tobacco blend 2 with 200.2 239.0 0.84 197 0.015 296 0.032 30% clove 7 Tobacco blend 2 with 196.7 239.8 0.82 211 0.016 360 0.039 40% clove 8 Tobacco blend 2 with 208.7 251.0 0.83 208 0.016 366 0.035 50% clove

[0187] Values listed for Sample 2 are an average of values obtained from two 100% clove samples.

[0188] In Table 4, “MD” refers to machine direction, that is, the direction in which the sheet material would be rolled onto or unrolled from a bobbin and fed into a machine; “CD” refers to cross direction, which is perpendicular to the machine direction. See FIGS. 8 and 9.

[0189] From Table 4, it can be seen that homogenised sheets comprising clove particles as described herein exhibit tensile strengths at peak in both the cross direction and the machine direction that are higher than for the comparable density 100% tobacco cast leaf sheet.

[0190] While several illustrative embodiments of the invention have been shown and described, numerous variations and alternate embodiments will occur to those skilled in the art. Such variations and alternate embodiments are contemplated, and can be made without departing from the scope of the invention.