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EP 1 051 089 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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07.05.2003 Bulletin 2003/19 |
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Date of filing: 26.01.1999 |
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International application number: |
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PCT/GB9900/260 |
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International publication number: |
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WO 9903/8396 (05.08.1999 Gazette 1999/31) |
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SMOKING ARTICLES
RAUCHARTIKEL
ARTICLES A FUMER
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Designated Contracting States: |
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AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE |
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Priority: |
28.01.1998 GB 9801797
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Date of publication of application: |
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15.11.2000 Bulletin 2000/46 |
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Proprietor: British American Tobacco (Investments) Limited |
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London WC2R 3LA (GB) |
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Inventor: |
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- SAMPSON, John Roger
Hertfordshire AL7 4EU (GB)
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Representative: Walford, Margot Ruth |
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Patents Department
British American Tobacco (Investments) Limited
R & D Centre
Regents Park Road Southampton SO15 8TL Southampton SO15 8TL (GB) |
(56) |
References cited: :
EP-A- 0 378 774 GB-A- 1 512 352
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GB-A- 1 348 580 US-A- 5 056 537
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] This invention relates to smoking articles such as cigarettes, cigars and cigarillos,
and is concerned with the reduction of sidestream smoke from smoking articles. Sidestream
smoke is that which is produced when the article is alight but not being drawn on
by the smoker. Mainstream smoke is that which is generated when the smoking article
is drawn on by the smoker; the chemistries of mainstream and sidestream smokes are
different.
[0002] Sidestream smoke is perceived to be annoying to non-smokers, especially when a cigarette
is left lying as for example in an ashtray, and any reduction in it is desirable.
The modification of mainstream smoke affects the perception of the article by the
smoker.
[0003] The present invention uses activated carbon to modify the smoke of a smoking article.
Of course, activated carbon has been used in smoking articles, and for various purposes,
virtually ever since its excellent adsorbent properties became known.
[0004] For example, the effects of various carbon contents of filters have been investigated
by Williams et al in a report presented to the 5th General Assembly of CORESTA, Vienna,
October 1964 and reprinted in Beiträge zur Tabakforschung, Vol. 3 part
3, pages 233-242. This showed varying adsorbence of different constituents of mainstream
smoke by filter shreds of different make-up. However we are concerned with placing
of carbon in the tobacco rod; that is, where it is subjected to conditions very different
from those in a filter.
[0005] GB-A-1512352 shows the use of activated porous particles of carbon adhered to tobacco
in the tobacco rod to affect mainstream smoke. GB-A-1348580 shows a sheet of reconstituted
tobacco material containing activated carbon used as a main material for making cigarettes
which gave a reduction in particulates and nicotine in mainstream smoke.
[0006] As far as we are aware at present the only disclosure of the use of carbon in a tobacco
rod in a situation where reduction of sidestream smoke was aimed for is in US-A-5092353
(EP-A-378774). However the aim in that disclosure was to reduce sidestream smoke by
the use of wrapping paper of very low permeability (< 10 CORESTA units). To compensate
for the tendency this will cause for the cigarette to be self-extinguishing, pyrolyzed
alpha-cellulose was present in the tobacco rod.
[0007] This pyrolyzed material was not subjected to any activating treatment. No mention
is made of any chemical effect it might have on the smoke, and it probably has little
or none because in the specific example the pyrolyzed material was cotton linters,
which would give a comparatively low surface-area carbon.
[0008] The present invention, therefore, is contrasted with all of this prior art by providing
in a tobacco rod an activated carbon for having an effect on the chemistry of smoke
while not being limited to the use of low permeability papers, and specifically not
to papers of < 10 CORESTA.
[0009] Furthermore, the present invention provides the addition of activated carbon in specific
particulate form in reconstituted tobacco sheet to the tobacco rod of the smoking
article in such a way that greater mildness of the smoking article is perceived by
the smoker in the mainstream smoke, and at the same time there is a reduction in sidestream
smoke over a wide range of porosities of the wrapper of the article and in particular
with porosities high enough that special precautions do not have to be taken to prevent
self-extinction of the article.
[0010] Furthermore, the activated carbon particle should preferably be of vegetable origin
since they will then contain minute traces of metals, which assist in the firm adsorption
of (particularly) aldehydes from the smoke and indeed may chelate with such compounds.
These are compounds the removal of which is particularly critical for improving mildness
of perception of the article when smoked.
[0011] At the same time, however, the activated carbon does not diminish and may even increase
certain beneficial volatile components of the smoke.
[0012] It is important to realise that as the "coal" of the smoking article progresses along
the article, smoke components adsorbed by the particles are displaced from those particles
minimally if at all. They are destroyed to gaseous oxides together with the material
of the carbon particle itself by the extremely high temperatures (reaching up to about
800°C) generated in the coal.
[0013] The reconstituted tobacco sheet containing the activated carbon particles may be
made by conventional techniques for making such sheets, which in their turn resemble
conventional paper-making techniques, the sheet then being shredded for incorporation
with shredded tobacco which will be the material of the tobacco rod.
[0014] An important application of the present invention however will be in "roll your own"
tobacco blends, i.e. those which are sold loose and which are wrapped in cigarette
papers by the smoker.
[0015] The invention therefore includes within its scope a blend of shredded tobacco and
of reconstituted tobacco sheet with the latter containing activated carbon.
[0016] The handling of the sheet, whether in shredding or in later manipulation either in
a machine or by the smoker, may cause loss of carbon particles and the reconstituted
tobacco sheet may be coated or sized in order to assist retention of the particles
in it, and in particular the particles may themselves be micro-encapsulated before
incorporation. This latter has the advantage of increasing the size of the particles
and therefore their retention mechanically and the uniformity of size but, perhaps
surprisingly, does not affect their activity.
Example 1
[0017] Cigarettes were made from a mixture of US flue-cured and Burley tobaccos, cut rolled
stem and expanded tobaccos, processed and cut to 32 cuts per inch ("cpi"). Incorporated
in the shredded tobacco were 20% of a reconstituted tobacco sheet equally cut and
containing 30% of activated carbon particles from coconut, of mean particle size 37
µm and ranging in particle size from 0.5 µm to 150 µm. Control cigarettes were made
identically but with the omission of the activated carbon particles.
[0018] The cigarettes were 84 mm long, 7.9 mm diameter, unfiltered. The wrapping was an
80 CORESTA flax-based paper, with 2% potassium citrate burn enhancer.
[0019] The cigarettes were subjected to smoking on a standard smoking machine and the mainstream
smoke was analysed for vapour phase and semi-volatiles content with the results shown
in Tables 1 and 2.
[0020] As seen in Table 1, there was a striking diminution, selective in character, of certain
aldehydes and ketones and in particular of acrolein and butyraldehydes, the removal
of which is important for mildness of taste. On the other hand, there was an actual
increase as compared to the standard in certain ingredients, and in particular limonene,
which are regarded as beneficial to the taste.
[0021] A similar reduction though less selective is seen in the semi-volatiles as shown
in Table 2.
Example 2
1. A smoking article having a tobacco rod which comprises a blend of shredded tobacco
and shredded reconstituted tobacco sheet, the reconstituted tobacco sheet containing
activated carbon particles, and a wrapper around the tobacco rod, the wrapper having
an inherent permeability of 20 CORESTA or greater.
2. An article according to Claim 1 in which the activated carbon particles are of vegetable
origin.
3. An article according to Claim 2 wherein the vegetable origin is coconut.
4. An article according to Claim 1, Claim 2 or Claim 3 wherein the carbon particles have
a mean particle size of about 37µm.
5. A method of producing a smoking article with reduced sidestream smoke and increased
perceived mildness during smoking which includes using for the tobacco rod of the
article shredded tobacco and shredded reconstituted tobacco sheet containing activated
carbon particles, and as the wrapper of the smoking article a material having an inherent
permeability of 20 CORESTA or greater.
6. A method according to Claim 5 including hand-rolling the smoking article.
7. A method according to Claim 5 or Claim 6 which involves preferential reduction in
the aldehyde content of mainstream smoke.
8. A kit for hand-rolling a smoking article with reduced sidestream smoke and increased
perceived mildness during smoking which includes for the tobacco rod of the article
shredded tobacco and shredded reconstituted tobacco sheet containing activated carbon
particles, and as the wrapper of the smoking article a material having an inherent
permeability of 20 CORESTA or greater.
1. Rauchartikel mit einem Tabakstrang, der eine Mischung bzw. einen Blend aus zerkleinertem
Tabak und einem zerkleinerten Flächengebilde bzw. Blatt aus rekonstituiertem Tabak
aufweist, wobei das Flächengebilde bzw. Blatt aus rekonstruiertem Tabak Aktivkohle-Teilchen
enthält, und eine Umhüllung um den Tabakstrang aufweist, wobei die Umhüllung eine
inhärente Durchlässigkeit von 20 Coresta-Einheiten oder mehr hat.
2. Artikel nach Anspruch 1, bei dem die Aktivkohle-Partikel pflanzlichen Ursprungs sind.
3. Artikel nach Anspruch 2, wobei der pflanzliche Ursprung Kokosnuss ist.
4. Artikel nach Anspruch 1, Anspruch 2 oder Anspruch 3, wobei die Kohle(nstoff)-Partikel
eine mittlere Partikelgröße von ungefähr 37 µm haben.
5. Verfahren zur Erzeugung eines Rauchartikels mit reduziertem Nebenstrom-Rauch und erhöhter,
empfundener Milde während des Rauchens, das die Verwendung von zerkleinertem Tabak
und zerkleinertem Flächengebilde aus rekonstruiertem Tabak, das Aktivkohle-Partikel
enthält, für den Tabakstrang und als die Umhüllung des Rauchartikels ein Material
mit einer inhärenten Permeabilität von 20 Coresta-Einheiten oder mehr umfasst.
6. Verfahren nach Anspruch 5, einschließlich des Handrollens des Rauchartikels.
7. Verfahren nach Anspruch 5 oder Anspruch 6, das die bevorzugte Reduktion des Aldehyd-Gehaltes
des Hauptstrom-Rauchs involviert.
8. Kit bzw. Bausatz zum Handrollen eines Rauchartikels mit verringertem Nebenstrom-Rauch
und erhöhter, empfundener Milde während des Rauchens, der für den Tabakstrang des
Artikels zerkleinerten Tabak und zerkleinertes Flächengebilde aus rekonstruiertem
Tabak, das Aktivkohle-Partikel enthält, und als die Umhüllung des rauchbaren Artikels
ein Material mit einer inhärenten Permeabilität von 20 Coresta-Einheiten oder mehr
umfasst.
1. Article à fumer ayant une tige de tabac, laquelle comprend un mélange de tabac haché
et de feuille hachée de tabac reconstitué, la feuille de tabac reconstitué, contenant
des particules de charbon actif, et une enveloppe entourant la tige de tabac, l'enveloppe
ayant une perméabilité inhérente de 20 CORESTA ou supérieure.
2. Article selon la revendication 1, dans lequel les particules de charbon actif sont
d'origine végétale.
3. Article selon la revendication 2, dans lequel l'origine végétale est de la noix de
coco.
4. Article selon la revendication 1, 2, ou 3, dans lequel les particules de charbon ont
une taille moyenne de particules d'environ 37 µm.
5. Procédé de production d'un article à fumer doté d'une fumée de courant secondaire
réduite et d'une sensation de douceur accrue durant l'action de fumer, qui comprend
l'utilisation, pour la tige de tabac de l'article de tabac haché et de feuille hachée
de tabac reconstitué, contenant des particules de charbon actif, et comme enveloppe
entourant la tige de tabac, d'un matériau ayant une perméabilité inhérente de 20 CORESTA
ou supérieure.
6. Procédé selon la revendication 5, incluant le roulage manuel de l'article à fumer.
7. Procédé selon la revendication 5 ou 6, comportant une réduction préférentielle de
la teneur en aldéhyde de la fumée de courant principal.
8. Ensemble pour le roulage manuel d'un article à fumer avec fumée de courant secondaire
réduite et sensation de douceur accrue durant l'action de fumer, qui comprend pour
la tige de tabac de l'article, du tabac haché et de la feuille hachée de tabac reconstitué,
contenant des particules de charbon actif, et comme enveloppe entourant la tige de
tabac, un matériau ayant une perméabilité inhérente de 20 CORESTA ou supérieure.