6370 8 9 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION FOR OFFICE USE: Class Application Number: Lodged: Complete Specification Lodged: Accepted: ,,Published: riority:
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Related Art: Int.Class Name of Applicant: BRITISH-AMERICAN TOBACCO COMPANY LIMITED Address of Applicant: Westminster House, 7 Millbank, London SW1P 3JE, England Actual Inventor: lan Campbell Brown, David John Dittrich and Richard Thomas Fiebelkorn Address for Service: SHELSTON WATERS, 55 Clarence Street, Sydney Complete Specification for the Invention entitled: "IMPROVEMENTS RELATING TO SMOKING ARTICLES" The following statement is a full description of this invention, including the best method of performing it known to us:- 1 la IMPROVEMENTS RELATING TO SMOKING ARTICLES The invention the subject of this application relates to cigarettes and similar smoking articles.
It is an object of the subject invention to provide a cigarette which is of a low tar delivery but which is sensorily acceptable to the smoker.
The subject invention provides a smoking article comprising a tobacco rod, which rod comprises cut tobacco and a paper wrapper circumscribing said tobacco, 50% or more of said tobacco having been treated with a humectant to provide a loading level of said humectant of 4% to by weight of said tobacco, said tobacco comprising expanded tobacco, the packing density of said tobacco rod not exceeding 210 mg/cc, and wherein, when said article is smoked under standard machine smoking conditions, the particulate matter delivery on a water, nicotine and humectant free basis to nicotine delivery ratio is not more than 6 to 1. Suitably, the loading level of the humectant on the tobacco is not less than 5% and does not exceed 12%. More suitably, the loading level is in the range of 7 10%, 9% for example.
The humectant is suitably one or more of glycerol, propylene glycol, sorbitol and diethylene glycol.
Advantageously, the humectant is applied to the tobacco prior to the tobacco being subjected to an expansion process. The loading level of the humectant on the tobacco prior to expansion may be in a range of about to about 20% in order to result in a post expansion
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T a Tr 0lb level of 4% to We have found that if the humectant is applied to the tobacco before rather than after the tobacco is subjected to the expansion process, a reduction in tobacco strand length during the process is avoided.
Further e e oooo I ooo ;V9 A 2 of applying the humectant prior to expansion reside in the avoidance of an undesirably high equilibrium moisture content post expansion and the avoidance of a reduction in the filling power of the expanded tobacco.
Suitably, the humectant is applied to the tobacco by being sprayed thereon, advantageously in aqueous solution.
The humectant should, before the tobacco is subjected to the expansion process, be distributed of the tobacco with a significant degree of uniformity, which objective may be furthered by tumbling the tobacco and/or allowing the tobacco to stand in bulk for a sufficient time after the application of the humectant.
Tobacco of smoking articles according to the subject invention which is to be subjected to an expansion process is suitably pre-conditioned to a moisture content in a e range of 22% to 30% and preferably to a moisture content in a range of 26% to Tobacco of smoking articles according to the subject invention which is subjected to an expansion process may 20 be lamina and/or stem tobacco. The expanded tobacco advantageously comprises a lamina tobacco the product of a tobacco expansion process which is effective to provide a high degree of expansion in tobacco subjected to the process. High expansion processes are disclosed, for example, in the specification of United States Reissue Patent No. 30,693 and in United Kingdom Patent Specifications Nos. 1,570,270 and 2 160 408A. By use of 3 high expansion processes, tobacco expansion values, in terms of filling value increase, of from about, typically, and even up to about 125% may be obtained. Tobacco which has been subjected to a high expansion process may have a bulk density of, for example, from about 100 mg/cc to about 200 mg/cc, and preferably not less than 150 mg/cc, as measured using a Borgwaldt Densimeter.
A minor proportion of the smoking material of smoking articles according to the subject invention may take the form of reconstituted tobacco and/or tobacco substitute material. Preferably though, the smoking material should be wholly natural cut tobacco. It is also preferable that the whole or a substantial proportion of the cut tobacco of smoking articles according to the subject invention should be expanded tobacco and that the whole of this
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expanded tobacco should have been treated with humectant °ooo prior to being expanded. Suitably, at least 65% of the tobacco is treated expanded tobacco, and more suitably 0 is treated expanded tobacco.
The weight of the smoking material in a cigarette 0004 o according to the subject invention is suitably in a range S e 0 of 500 to 800 mg.
Suitably, the packing density of the smoking material of smoking articles according to the subject invention does not exceed 210 mg/cc.
It is to be observed that when measurement is made of the PMWNF delivery of a smoking article according to the 4 subject invention, the value obtained includes a proportion of the humectant. It may thus be of interest to express particulate matter delivery on a water, nicotine and humectant free basis (PMWNHF). Preferably, the PMWNHF to nicotine delivery ratio of smoking articles according to the subject invention is not more than 8 to 1 and is preferably in the region of 6 to 1, and more preferably in the region of about 5 to 1.
The humectant in the mainstream smoke of cigarettes according to the subject invention, as measured under e. C standard machine smoking conditions, preferably forms not less than 15%, and more preferably not less than 20%, of the mainstream PMWNF. Yet more preferably the mainstream smoke humectant forms approximately 25% of the mainstream PMWNF. Suitably, the mainstream smoke humectant may also e^ee be in the range 24% to 26%, 24% for example.
A burn retardant may be used in smoking articles in accordance with the subject invention. The burn retardant may be, for example, magnesium chloride, sodium chloride, ammonium sulrhate, ammonium lactate, or mixtures thereof,
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applied to the smoking material.
According to a further aspect thereof, the subject invention provides a tobacco treatment comprising the application of a humectant to tobacco and, subsequent to said application, the expanding of said tobacco, the application level of said humectants to said tobacco before the expansion step being such that the loading 5 level of said humectant after said tobacco has been expanded is in a range of 4% to 15% by weight.
In order to further the understanding of the subject invention, examples according thereto will now be described.
EXAMPLE I To a cut tobacco blend comprising 20% water treated stem, 40% burley tobacco lamina and 40% flue cured tobacco lamina there was added glycerol at a 10% loading level and magnesium chloride at a 1% loading level. The blend was conditioned to 25% moisture content, the blend being thereafter subjected to a high level expansion process.
The glycerol loading on the expanded tobacco was about 6%.
Using the thus obtained expanded tobacco, 24.75 mm circumference cigarettes were made. Each cigarette comprised a 64 mm long tobacco rod consisting of 100% of the expanded tobacco and of wrapper of a standard commercial cigarette paper. The packing density of the tobacco in the tobacco rods was about 145 mg/cc. To each 20 of the tobacco rods there was attached, by a tipping C e wrapper, a 20 mm long cellulose acetate filter plug. The cigarettes were laser ventilated at the filters to provide a ventilation value of These cigarettes were smoked under standard (Coresta) machine smoking conditions according to which a 35 cm puff of two seconds duration is taken every minute and were found to yield mainstream smoke component deliveries 6 as follows.
Component Delivery (mg) TPM 5.88 Nicotine 0.63 PMWNF 4.37 Glycerol 1.35 PMWNHF 3.02 It is thus to be observed that the PMWNHF to nicotine S ratio was 4.8. It may also be observed that the glycerol 10 delivery represented 31% of the PMWNF delivery.
*e It was found that when smoked under Coresta machine smoking conditions, a commercially available cigarette, Benson Hedges Ultra (Trade Mark), of similar delivery, i.e. 5.57 mg TPM, had a mainstream glycerol delivery of 0.44 mg, this representing 9.4 per cent of the PMWNF S delivery. The PMWNHF to nicotine ratio of 4the Ultra cigarettes was 9.9.
In sensory panel smoking tests it was found that the above detailed cigarettes according to the subject 20 invention exhibited sensory features superior to those of e the Ultra cigarettes.
EXAMPLE II To a first cut tobacco blend comprising 65% flue cured lamina and 35% burley lamina was added glycerol at a 6% loading level and ammonium lactate at a 2% loading level. The blend was conditioned to a 30% moisture content, the blend being thereafter subjected to the high 7 level DIET expansion process. The glycerol loading level on the expanded tobacco was 4.4%.
A second cut tobacco blend comprised 50% burley lamina and 50% sun cured oriental lamina. The second blend was not subjected to an expansion process.
The first and second blends were combined in the proportions 70% first to 30% second and to the thus obtained combined blend was added propylene glycol at a loading level. Thus the total loading level of 30 humectant, glycerol plus propylene glycol, was 4.6%.
go e* 0 Using the tobacco of the combined blend 24.75 mm circumference cigarettes were made. Each cigarette comprised a 59 mm long tobacco rod and a standard commercial cigarette paper. The packing density of the tobacco in the rods was 190 mg/cc. To each of the rods there was attached a 25 mm long dual filter comprising a 7 mm long section of crimped paper and an 18 mm long section of cellulose acetate filtration material. The cigarettes were laser ventilated at the cellulose acetate sections of the filters to provide a ventilation of 0@ When smoked under standard machine smoking conditions, mainstream smoke component deliveries were found to be as follows: Component Delivery (mg) TPM 6.79 Nicotine 0.84 PMWNF 5.43 8 Component Delivery (mgql Glycerol 1.00 Propylene glycol 0.28 PMWNHF 4.15 Thus the PMWNHF to nicotine ratio was 4.9 and humectant represented 24% of the PMWNF delivery.
A commercially available cigarette of similar delivery, namely Camel Lights (Trade Mark), was found to have a mainstream glycerol delivery of 0.39 mg, this S..'13 representing 8% of the PMWNF delivery. The PMWNHF to oC nicotine ratio of Camel Lights was 9.7.
EXAMPLE III A cut tobacco blend comprised 25% burley lamina, flue cured lamina, 25% water treated stem and 10% sun 5 cured oriental lamina. To this blend was added glycerol at a 10% loading Jevel and magnesium chloride at a 1% loading level. The blend was thereafter subjected to a high level expansion process. The glycerol loading level on the expanded tobacco was 8%.
20 Using the thus obtained tobacco cigarettes were made which were to the same format as the cigarettes according to the invention of Example I. When smoked under standard machine smoking conditions, mainstream smoke component deliveries were found to be as follows: Component Delivery (mg) TPM 6.55 Nicotine 0.54 9- Component Delivery (mg) PMWNF 4.93 Glycerol 1.63 PMWNHF 3.30 Thus the PMWNHF to nicotine ratio was 6.1 and the humectant represented 33% of the PMWNF.