GB2087214A - Smokeable mixture and method of making same - Google Patents

Abstract

Manufacture of nicotine-fortified smokeable mixture from a blend of a) reconstituted tobacco sheet containing Nicotiana rustica and b) tobacco other than Nicotiana rustica wherein the sheet is made by a dry process so as not to lose the water-soluble nicotine. The sheet preparation may involve casting onto a drying band or the use of a roll mill or an extruder.

Description

SPECIFICATION Smokeable mixture and method of making same Technical field The invention relates to a smokeable mixture fortified with nicotine and also to a method of making such a mixture. The mixture contains tobacco and may also contain a tobacco substitute. The term "tobacco substitute" means a solid substance not of tobacco origin which is smokeable in the same manner as tobacco.

The invention uses as a source of nicotine a plant species called Nicotiana rustica (hereinafter N. rustica) which as is well known contains a high proportion of nicotine, e.g. up to 14% by weight.

The term "lamina" is used in this specification to mean leaf which includes the mid-rib or leaf from which at least part of the mid-rib has been removed.

Background art There are a number of ways of increasing, i.e. fortifying, the nicotine content in tobacco. If liquid nicotine is incorporated in reconsituted tobacco sheet as an additive a manufacturing problem arises due to the high toxic nature of the pure nicotine additive. If a nicotine salt is incorporated in the sheet and the pH factor is too high, the salt is converted to produce free nicotine which is volatile and thus easily lost. If Nicotiana rustica lamina is directly added to the tobacco it is difficult to control the amount of added nicotine because the proportion of nicotine in the donor N. rustica may vary according to the region of supply and to other growing conditions. If however the tobacco itself is N. rustica it has a very marked flavour which may not be desired.

In an attempt to avoid these problems, reconstituted tobacco sheet comprising tobacco offal, a binder and N. rustica lamina has been prepared using a conventional paper-making technique which is a wet process.

However it was found that this process not only incurred high energy costs associated with a wet process but also resulted in an unacceptable loss of nicotine which is soluble in water. In addition it was found that due to its sticky nature the maximum amount of N. rustica which could be handled by the sheet-making apparatus was about 30% by weight of the sheet constituents. As a result the amount of nicotine in the final sheet was correspondingly limited.

The present invention provides nicotine fortification which can be closely controlled over a wide range of fortification by a method which does not present a manufacturing health hazard and avoids the above-mentioned difficulties associated with a conventional paper-making technique.

Invention A method of making a nicotine-fortified smokeable mixture comprising the steps of a) preparing a sheet of reconstituted tobacco which contains Nicotiana rustica, b) converting the sheet into small portions, c) and blending said portions with tobacco other than Nicotiana rustica to produce a smokeable mixture characterised in that in step a) the sheet is made by a process wherein the water-soluble constituents of the tobacco are retained in the sheet.

The inventive method will now be described in the following Examples.

Example 1 All calculations are made on a dry weight basis.

Firstly, the amount of added nicotine to be provided by the reconsituted sheet portions to the smokeable mixture is decided, say 0.8%. From tests it is known that the dried N. rustica lamina to be used contains 7% nicotine and that the factory tobacco offal or waste which also is to be incorporated in the sheet contains 1.5% nicotine.

Since the required amount of nicotine to be added by the sheet is 0.8% and since in this Example the sheet will represent 20% of the final smokeable mixture, then the nicotine content of the donor sheet will be 0.8 100 20 x 1 =4%.

Let the weight of N. rustica lamina to be incorporated in the sheet be x% and the offal be (100 - x)%. Then 4(nicotine content of donor sheet) = 7x 1.5(100 - x) 100 100 . . 4 = 0.056x + 1.5 . . x = 45.5% However this particular sheet is to include 5 part of SCMC (sodium carboxy methylcellulose) as binder to a 100 parts of tobacco, consequently the tobacco will consitutute only 100/105 of the total sheet and so to obtain the selected 4% nicotine content of the sheet the amount of N. rustica lamina in the sheet requires to be slightly increased to 45.5 105 100 l= 47.8%.

From these calculations the sheet formulation is as follows.

47.8 parts N. rustica lamina as nicotine donor.

52.2 parts tobacco offal.

5.0 parts SCMC as binder additive.

5.0 parts of a 40% (w/w) glyoxal solution as a wet strength additive.

The above dry basis weights have to be corrected for moisture. If the residual mositure content of the dried N. rustica is M% the actual amount of N. rustica to be incorporated in the sheet to give 47.8 parts is slightly higher, viz.

47.8 100 (100-M) 1 The sheet formulation having now been finally calculated the sheet is produced in the following manner.

The dried N. rustica lamina and larger particles (greater than 125 microns) of the tobacco offal are ground in water in a mill to give the required reduction in particie size. The remaining smaller particles (less than 125 microns) of the tobacco offal together with the SCMC and the glyoxal solution are then added and throughly mixed in a high-shear mixer with the ground N. rustica lamina and its accompanying offal particles. The resultant homogeneous slurry which has a 10% solids content is cast directly from a hopper onto a stainless steel drying band to form a thin reconstituted tobacco sheet. The sheet is then cut into small portions ready for blending with tobacco. The portions may for example be 5.08 cm square. The sheet may be cut by apparatus of the kind described in our UK Patent No. 1426785.

Finally the sheet portions are blended, e.g. in a rotary drum, with cigarette tobacco and the blend converted by cutting to a smokeable mixture form which is then used as a nicotine-fortified cigarette filler in a cigarette making machine.

When for example these sheet portions were blended with tobacco used as filler for filter cigarettes sold under the brand EMBASSY it was found that during smoking the expected increase in smoke nicotine delivery was not accompanied by any corresponding increase in the delivery of carbon monoxide or of tar.

Example 2 After the appropriate calculations the following mixes are prepared.

Mix 1. 88.8 parts N . rustica lamina as nicotine donor.

5.5 parts SCMC as binder additive.

Mix 2. 3.7 parts butylene glycol as humectant.

2.0 parts glyoxal as wet strength additive.

35.2 parts water.

The two mixes are mixed together and the resultant dough of iow-water content is passed through a roll mill and dried to form a thin tobacco reconstituted sheet. The dried sheet is cut into small portions ready for blending with tobacco. The sheet portions are then blended with cigarette tobacco and the blend coverted to a smokeable mixture form which is subsequently used as a nicotine-fortified cigarette filler in a cigarette making machine.

Example 3 Afterthe appropriate calculations, a 100 parts of dried N. rustica lamina is dry milled to produce a particie size of less than 250 microns. The milled lamina together with 10 parts SCMC and 2 parts glyoxal is mixed with water, the mixture having a high solids content of 45 - 60%. The mixture is then extruded between a pair of contra-rotating rollers onto a drying band to form a reconsituted tobacco sheet. The extrusion may be carried out by the method described in our UK Patent Application No. 8004414 filed February 9th 1980.

The dried sheet is then blended with cigarette tobacco and the blend converted to a smokeable mixture form which is subsequently used as a nicotine-fortified cigarette filler in a cigarette making machine.

In each of the above examples the smokeable mixture comprises a blend of tobacco (other than N. rustica) and cut portions of a reconstituted tobacco sheet which a) has been made by a relatively dry process in contrast to a wet process involving large amounts of water and b) comprises N. rustica.

The amount of N. rustica in the sheet may vary widely from 1% to nearly 100% by weight.

The amount of sheet portions in the smokeable mixture may also vary widely from 1% upwards, e.g. about 10% to about 20%.

By adding such N. rustica reconstituted tobacco sheet to an existing tobacco, or to an existing tobacco/tobacco substitute mixture, it is possible to provide a smokeable mixture with a controiled amount of nicotine fortification irrespective of the growing conditions of the tobaccos in the mixture. The existing tobacco may be one normally used to produce a low tar cigarette, i.e. a cigarette which, when smoked, delivers less than 10 milligrams of tar but is not so limited.

One advantage of using a relatively dry process to make the reconstituted sheet is that the slurry or dough may be held at a temperature of about 80"C for several hours without appreciable loss of nicotine, provided the pH factor does not rise, before forming the sheet. This feature is advantageous in sheet production.

The invention is not limited to use in cigarette filler tobacco but may be used to provide a smokeable mixture for pipe smokers.

Claims (8)

1. A method of making a nicotine-fortified smokeable mixture comprising the steps of preparing a sheet of reconstituted tobacco which contains Nicotiana rustica, b) converting the sheet into small portions, c) and blending said portions with tobacco other than Nicotiana rustica to produce a smokeable mixture characterised in that in step a) the sheet is made by a process wherein the water-soluble constituents of the tobacco are retained in the sheet.

2. A method according to claim 1, characterised in that step a) comprises milling a mixture of Nicotiana rustica lamina and tobacco offal with water, adding to the mixture additives known in tobacco sheet-forming techniques and mixing to form a homogenous siurry, and casting the slurry onto a drying band to form a tobacco reconstituted sheet.

3. A method according to claim 1 characterised in that step a) comprises mixing Nicotiana rustica lamina, a binder additive and a wet strength additive with water to form a dough, passing the dough through a roll mill, and drying it to form a tobacco reconstituted sheet.

4. A method according to claim 1, characterised in that step a) comprises mixing dry finely milled Nicotiana rustica lamina with a binder additive a wet strength additive and water to form a mixture having a solids content of 45 - 60%, and extruding the mixture onto a drying band to form a tobacco reconstituted sheet.

5. A method of making a nicotine-fortified smokeable mixture substantially as described herein with reference to Example 1.

6. A method of making a nicotine-fortified smokeable mixture substantially as described herein with reference to Example 2.

7. A method of making a nicotine-fortified smokeable mixture substantially as described herein with reference to Example 3.

8. A nicotine-fortified smokeable mixture made by the method of any preceding claim.