HK1071277B - Smoking articles and smokable filler materials therefor - Google Patents

Description

Tobacco product and smokable filler material therefor

Technical Field

The present invention relates to tobacco (smokable) filler materials, which may be tobacco substitute materials, and tobacco products incorporating such materials.

Background

It has been an object for many years to provide a smokable filler material which can reduce the amount of biomass to reduce the potential health problems associated with the combustion of such biomass, i.e. tobacco. To this end, a large number of prior art proposals have been made relating to tobacco substitute materials or alternative smoking materials. One problem with these alternative materials is that as the amount of combustible substance in the smoking material decreases, the combustion properties of the alternative material are difficult to control. This requires certain well known combustion modifiers, for example combustion additives such as alkali metal salts of organic acids, for example sodium or potassium acetate, or flame retardants such as calcium or magnesium chloride to control the rate of combustion.

U.S. Pat. No.4,109,664 describes the use of a cellulosic binder, at least a portion of which is a thermogelling substituted cellulose, and air bubbles are bubbled through the slurry using a high speed shear mixer. International patent application publication No. WO 96/07336 and european patent application 0419975 describe smoking materials using inorganic fillers (sometimes agglomerated, as described in EP 0419975), binders and aerosol generating agents. None of these documents mentions the particle size of the inorganic filler, nor their effect on the static burn rate of tobacco products comprising these smoking materials.

Disclosure of Invention

The present invention is based on the discovery and production of a novel smoking material (smoking material) incorporating a non-combustible inorganic filler having an average particle size which has a beneficial effect on the combustion properties of the smoking material.

It is a further object of the present invention to provide a smoking material which has a beneficial effect on one or more of the taste, smoking mouthfeel or ash properties of a smoking article incorporating the material.

It is a further object of the present invention to provide a method for controlling the delivery per puff of a smoking article incorporating the new smoking material.

It is a further object of the present invention to provide a method for controlling the static burn rate of a smoking material having a predetermined formulation.

The invention provides a smoking material comprising a non-combustible inorganic filler, a binder, an aerosol generating means, wherein the non-combustible filler comprises a proportion of material having an average particle size in the range 500 microns to 20 microns.

The invention also provides a method of controlling the static burn rate of a smoking article comprising a rod of smokable filler material wrapped in a wrapper, said smokable filler material incorporating a portion of smoking material comprising a non-combustible inorganic filler, a binder and an aerosol generating means, said inorganic filler comprising a portion of material having an average particle size in the range 500 microns to 20 microns, the particle size of the inorganic filler being selected to provide a desired static burn rate, and/or the amount of smoking material being selected in dependence on the amount of smoking material in the mixture of smokable filler material to provide a desired static burn rate.

The invention also provides a smoking article comprising a rod of smokable filler material wrapped in a wrapper, said smokable filler material incorporating a portion of a smoking material according to the invention.

Detailed Description

The inorganic filler preferably constitutes 60-90%, more preferably 65-85%, even more preferably greater than 65%, and more preferably > 70% by weight of the final sheet. Advantageously, the inorganic filler constitutes about 75% by weight of the final sheet.

The average particle size of the inorganic filler is preferably in the range of 500 microns to 30 microns, more preferably 400 microns to 50 microns, even more preferably 200 microns to 150 microns, and most preferably at about 170 microns. This particle size range is quite different from the particle size of the inorganic filler commonly used in alternative tobacco products, i.e., particle sizes of about 2-3 microns. For a single inorganic filler, the particle size may range from 1 micron to 1 millimeter (1000 microns). The inorganic filler may be ground, milled or deposited to a desired particle size.

Advantageously, the inorganic filler is one or more of perlite, alumina, diatomaceous earth, chalk, vermiculite, magnesium oxide, magnesium sulphate or other inorganic fillers. Suitable densities of the filler are in the range of 0.1 to 3.97g/cm³。

If a combination of inorganic fillers is used, one or more of the fillers may suitably be of small particle size and the other may be of larger particle size, the proportion of each filler being appropriate to achieve the desired average particle size. The static burn rate required in the final smoking article can be achieved by using an appropriate blend of tobacco and smoking material in a smokable filler material.

The inorganic filler is preferably not in agglomerated form and should require little pretreatment before use or may be classified.

The binder preferably constitutes 5-13%, more preferably more than 6%, and even more preferably more than 7% by weight of the final sheet. Advantageously, the binder constitutes about 7.5% by weight of the final sheet.

Advantageously the binder is an organic binder, and most advantageously an alginic binder. If the binder is a mixture of alginate and non-alginate binders, the binder preferably comprises at least 50% alginate, more preferably at least 60% alginate, and even more preferably at least 70% alginate. When a non-alginate binder is used, the amount of the required combination binder can be suitably reduced. The amount of alginate in the binder combination advantageously increases as the amount of the combined binder is reduced. Suitable binders include soluble alginates such as ammonium alginate, sodium calcium alginate, calcium ammonium alginate, potassium alginate, magnesium alginate, triethanol-amine alginate, and propylene glycol alginate. Other organic binders such as cellulosic binders, gums or gels may also be used. Suitable cellulosic binders include cellulose and cellulose derivatives, such as sodium carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, hydroxyethylcellulose or cellulose ethers. Suitable gums include gum arabic, gum ghatti, gum tragacanth, karaya, locust bean, acacia, guar, quince or xanthan gum. Suitable gels include agar, agarose, carrageenan, furoidan and furcellaran. Starch may also be used as the organic binder. Other suitable Gums may be selected by reference to a manual, such as Industrial Gums, e.g., whistler (Academic Press).

More preferred as the binder is an alginic binder. Alginates are preferred in the present invention because of their burning properties.

The aerosol generating agent preferably comprises 5 to 15%, more preferably 7 to 13%, and even more preferably 10 to 13% by weight of the final sheet material. The aerosol generating agent most preferably comprises 11-13% and may advantageously be 11.25% or l 2.5%. The amount of aerosol-generating agent is suitably selected in conjunction with the amount of tobacco material present in the mixture comprising the smokable filler material of the smoking article. For example, in a mixture comprising a high proportion of sheet material and a low proportion of tobacco material, a lower level of aerosol generating agent may be required in the sheet material.

Advantageously, the aerosol-generating agent or a part of the aerosol-generating agent may be encapsulated, preferably microencapsulated, or stabilized in some other way. In which case the amount of aerosol generating means may be above the given range.

The smoking article according to the invention preferably comprises a tobacco material treated with an aerosol generating agent. The amount of aerosol generating agent added to the tobacco is preferably 2-6% by weight of the tobacco, but may suitably be up to 12%.

Suitable aerosol generating agents include aerosol forming agents selected from polyols such as glycerol, propylene glycol and triethylene glycol; esters, such as triethyl citrate or triacetin, high boiling hydrocarbons, or non-polyols, such as ethylene glycol, sorbitol, or lactic acid. Combinations of aerosol generating agents may be used. An additional function of the aerosol generating agent is to plasticize the sheet material. Suitable additional plasticizers include water.

It is advantageous that the smoking material comprises a colourant to darken the material and/or a flavourant to impart a particular flavour. Suitable flavour or colourant materials include, for example, cocoa, licorice, caramel, chocolate or toffee. Finely ground, granulated or homogenized tobacco may also be used. Industrially acceptable food colouring agents may also be used, such as E150a (caramel), E151 (Brilliant Black BN, E153 charcoal or E155(brown HT.) suitable flavourants include for example menthol and vanillin other protective materials may also be suitable.

The colourant or flavourant is preferably present at 0-10%, more preferably 5-7% by weight of the final smoking material. Advantageously the colourant or flavourant comprises 5%, 6% or 7% of the final smoking material. For example, when the colorant or flavor is cocoa or licorice, the minimum amount is 2-3%. Suitable amounts of cocoa range from 0 to 5%, preferably about 4% by weight of the final smoking material; and licorice is used in an amount of 0-4%, preferably about 2%.

It is advantageous if in an alternative embodiment a food dye is used in an amount in the range of at least 0.5% by weight of the final smoking material. The colorant may be sprinkled into the sheet after sheet formation.

Fibers such as wood pulp or cellulose fibers may be added to provide the sheet with one or more of higher strength, lower density or higher fill value. The fibers may comprise 1-10%, preferably 2-5%, and even more preferably about 3% by weight of the final sheet.

Surprisingly, the sheet according to the invention has sufficient strength and has an acceptable density without the need for high shear mixing to create venting or the addition of a thermosetting adhesive. The tensile strength of the smoking sheet material is preferably in the range of 1-2N/mm. Although lower than conventional reconstituted tobacco sheets (because of the absence of fibers in these reconstituted sheets), the material is still strong enough to withstand the rigors of typical sheet processing. It is believed that this may be because a small amount of cross-linking occurs between the calcium ions of the chalk and the sodium ions of the sheet during drying. It has been found that an improvement in strength can be obtained if an additional amount of cross-linked calcium salt is added to the sheet slurry.

The density of the sheet, as measured by mercury porosimetry, is preferably in the range of 0.7 to 1.5g/cc, more preferably 0.9 to 1.2 g/cc. Mercury porosimetry gives apparent or contour densitometry values.

The filling value of the sheet is in the range of 1.2-1.8cc/g, suitably about 1.5 cc/g. The filling value of the regenerated tobacco sheet is in the range of 3-6 cc/g.

The smoking material is preferably mixed with a tobacco material to provide a tobacco filler material. Advantageously, a majority of the tobacco material is cut tobacco. For a full-scent product that delivers about 12mg of nicotine-free dry particulate matter (NFDPM), the mixing ratio of smoking material and tobacco material according to the invention is advantageously 25: 75 (smoking material: tobacco material) to 75: 25, preferably in the range of 60: 40.

Ventilation may preferably be used in tobacco products according to the invention to reduce the release to < 9mg NFDPM. The amount released may range from 2 to 6mg NFDPM. In addition, or in the alternative, the mixing ratio of the smokable filler material may be varied to increase the amount of smoking material according to the invention and thereby reduce the amount of smoke constituents released.

Applicants have found that by careful selection of the particle size of the inorganic filler, the static burn rate of the smoking material of the present invention can be varied for a given formulation without the need to modify the formulation. This is a new approach for product developers and cigarette manufacturers. Furthermore, the taste and flavour characteristics and physical properties of the smoking article incorporating the smoking material of the present invention may be controlled by the selection of the particle size of the inorganic filler.

The static burn rate of the tobacco product comprising the sheet of the invention is preferably from 3mm/min to 8 mm/min. More preferably, the static burn rate is in the range of 4 to 7.5mm/min, and most preferably the static burn rate is in the range of 4 to 6 mm/min.

Advantageously the smoking material is a tobacco-free sheet material.

The following examples serve to illustrate the invention.

Example 1

The smoking material according to the invention is prepared by: 3kg of a dry formulation consisting of 74% chalk (inorganic filler), 12% glycerol (aerosol generator), 8% sodium alginate (binder), 4% cocoa and 2% licorice (colorant/fragrance) were weighed out. 8 litres of water were added gradually to the dry mixture of chalk, glycerine, cocoa and licorice, alginate being added to the mixture together with the water. The mixture was mixed using a Silverson mixer until the slurry reached the appropriate viscosity (150,000 cps). The slurry was then cast using a heated drum caster to produce a 1 mm thick wet sheet. The material was cut up at 31cpi using a chopper, blended with cut tobacco and made into cigarettes. Cigarettes of 84 mm length containing 27 mm filters were wrapped with 50CU wrappers. Table 1 details the composition and physical properties of the chalk used. A control cigarette comprising 100% tobacco blend was used, which was an all-lamina blend (alllamina mix) consisting of flue-cured Burley and Oriental grade tobacco, wherein 40% of the blend was DIET expanded tobacco. Each set of test cigarettes comprised a blend of 40% tobacco and 60% smoking sheet material according to the invention. These cigarettes were smoked under ISO standardised mechanical smoking conditions, i.e. a smoke volume of 35ml lasting two seconds per minute.

TABLE 1

	S479	S480	S481	S482	S483	S484
							Static combustion speed (mm/min) of average particle size of chalk	100％ V100250μ-7.44.72	100％ V100250μ-7.15.09	100％ V60100-80μ-7.35.19	50％ pptd50％ V100--5.26.95	100％ pptd2μ5.17.07	--100％5.06.53

As can be seen from Table 1, the static burn rate of the tobacco product increases as the particle size decreases. By optimizing the particle size, a mixture of different particle sizes will provide a significant new approach for tobacco manufacturers.

Example 2

Another sheet was prepared by drum casting a formulation comprising 75.25% chalk, 11.25% glycerin, 7.5% binder, 4% cocoa and 2% licorice. The average particle size of the chalk is about 170 microns. Such sheets exhibit acceptable smoking characteristics and physical characteristics, such as soot.

Example 3

Three groups of cigarettes were produced in the same dimensions as example 1, one group comprising 100% tobacco (as in example 1), a second group comprising sheets using 100% V100 chalk, and a third group comprising sheets using 100% deposited chalk. The formulation of the sheet was the same as in example 2. The combustion tests given in table 2 were obtained under ISO standardized suction conditions.

TABLE 2

		S295 (100% tobacco)	S384 (100% V100 chalk)	S382 (100% deposition self chalkiness)
					Heat of the firealkane in the mixture (Kcal/cig)		1.8(7.54kJ)	1.7(7.12kJ)	1.5(6.28kJ)
Peripheral combustion	Amount of smoke emitted between smoke	767.8	762.0	765.6
					Flue gas	866.9	820.8	883.3
	Internal pyrolysis	Amount of smoke emitted between smoke	731.2	690.4					653.4
Flue gas					754.6	709.5	731.0

It is clear from table 2 that it is surprising that the smoking articles of the present invention, despite having a smokable filler material comprising 60% of the sheet material of the present invention, retain the same or similar burn properties as cigarettes comprising 100% tobacco.

Claims (30)

1. A smoking material comprising a non-combustible inorganic filler material comprising a proportion of material having a mean particle diameter in the range 500 to 20 microns, a binder and an aerosol generating means, the non-combustible inorganic filler material constituting 75 to 90% by weight of the smoking material, and the binder comprising an alginic binder in an amount of at least 50% of the total binder.

2. A smoking material comprising a non-combustible inorganic filler material, a binder and an aerosol generating means, the non-combustible filler material comprising a proportion of material having a mean particle size in the range 500 microns to 20 microns, the non-combustible inorganic filler material comprising 75 to 90% by weight of the smoking material, and the binder comprising an alginic binder and the smoking material being free of fibres.

3. A smoking material according to claim 1 or 2, wherein the inorganic filler material is present in the range of 75-85% by weight of the final sheet material.

4. A smoking material according to claim 1 or 2, wherein the inorganic filler material is present at 75% by weight of the final sheet material.

5. A smoking material according to claim 1 or 2, wherein the inorganic filler material has an average particle size in the range of 500 microns to 30 microns.

6. A smoking material according to claim 5, wherein the inorganic filler material has an average particle size in the range of 400 to 50 microns.

7. A smoking material according to claim 6, wherein the inorganic filler material has an average particle size in the range of 200 microns to 150 microns.

8. A smoking material according to claim 7, wherein the inorganic filler material has an average particle size of 170 microns or about 170 microns.

9. A smoking material according to claim 1 or 2, wherein the inorganic filler material is one or more of perlite, alumina, diatomaceous earth, chalk, vermiculite, magnesium oxide, magnesium sulphate or other inorganic filler materials.

10. A smoking material according to claim 1 or 2, wherein the density of the inorganic filler material is in the range of 0.1-3.97g/cm³。

11. A smoking material according to claim 1 or 2, wherein the binder is present in the range of about 5-13% by weight of the final sheet material.

12. A smoking material according to claim 11, wherein the binder is present in an amount of more than 6% by weight of the final sheet material.

13. A smoking material according to claim 12, wherein the binder is present in an amount of greater than 7% by weight of the final sheet material.

14. A smoking material according to claim 13, wherein the binder is present at 7.5% or about 7.5% by weight of the final sheet material.

15. A smoking material according to claim 2, wherein if the binder is a mixture of alginate and non-alginate binders, the binder comprises at least 50% alginate.

16. A smoking material according to claim 15, wherein the binder comprises at least 60% alginate.

17. A smoking material according to claim 1 or 2, wherein the binder comprises one or more of ammonium alginate, sodium calcium alginate, calcium ammonium alginate, potassium alginate, magnesium alginate, triethanolamine alginate and propylene glycol alginate.

18. A smoking material according to claim 1 or 2, wherein the aerosol generating means is present in the range of 5-15% by weight of the final sheet material.

19. A smoking material according to claim 18, wherein the aerosol generating means is present in the range of 7-13% by weight of the final sheet material.

20. A smoking material according to claim 19, wherein the aerosol generating means is present in the range of 10-13% by weight of the final sheet material.

21. A smoking material according to claim 18, wherein the aerosol former is one or more of a polyol, an ester, a high boiling hydrocarbon, or a non-polyol.

22. A smoking material according to claim 1, wherein the fibres are present in the range of 1-10% by weight of the final sheet material.

23. A smoking article comprising a smokable filler material wrapped in a wrapper, said smokable filler material incorporating a portion of smoking material, the smoking material (i) comprising: 75-90% by weight of the smoking material of a non-combustible inorganic filler, a binder comprising an alginic binder in an amount of at least 50% of the total binder, and an aerosol generating agent, the inorganic filler comprising a proportion of material having a mean particle size in the range 500 microns to 20 microns, or (ii) comprising: (ii) a non-combustible inorganic filler comprising a proportion of material having an average particle size in the range 500 to 20 microns, a binder and an aerosol generator, the non-combustible inorganic filler constituting 75 to 90% by weight of the smoking material, the binder comprising an alginic binder and no fibres being present in the smoking material, or (iii) three major components, respectively non-combustible inorganic filler, binder and aerosol generator, the non-combustible filler comprising a proportion of material having an average particle size in the range 500 to 20 microns and the three major components constituting 93.75 to 95% by weight of the smoking material; the particle size of the inorganic filler is selected to provide a desired static burn rate, and/or the amount of smoking material is selected to provide a desired static burn rate based on the amount of tobacco material in the smokable filler material mixture.

24. A smoking article according to claim 23, wherein said smoking article has a static burn rate of from 3mm/min to 8 mm/min.

25. A smoking article according to claim 24, wherein the static burn rate is from 4mm/min to 7.5 mm/min.

26. A smoking article according to claim 25, wherein the static burn rate is from 4mm/min to 6 mm/min.

27. A smoking article according to any one of claims 23-26, wherein said smoking article comprises tobacco material treated with an aerosol generating means, the aerosol generating means being incorporated into the tobacco in an amount of from 2 to 12% by weight of the tobacco.

28. A smoking article according to any one of claims 23 to 26, wherein the mixing ratio of smoking material according to the invention and tobacco material is from 25: 75 (smoking material: tobacco material) to 75: 25.

29. A smoking material comprising three major components, respectively, a non-combustible inorganic filler, a binder and an aerosol generating means, the non-combustible filler comprising a proportion of material having an average particle size in the range 500 microns to 20 microns, and the three major components comprising 93.75 to 95% by weight of the smoking material.

30. A smoking material comprising a non-combustible inorganic filler material comprising a proportion of material having an average particle size in the range 500 to 20 microns, a binder and an aerosol generator, the non-combustible inorganic filler material being chalk in an amount of 74 to 90%, the aerosol generator material being glycerol in an amount of 11.25 to 15%, the binder being sodium alginate in an amount of 7.5 to 13%, all by weight of the smoking material.