Note: Descriptions are shown in the official language in which they were submitted.
~5~:iS8~3
This invantion relates to smo];ing r,ixtures a,,d
more particularly to smoking mixtures containing natural
or synthetic swelling clays.
Hereinafter we use the term "smectite" to indi-
cate a natural or synthetic swelling clay. This usage of
the term includes montmorillonite, beidellite, non-tronite,
saponite, hectorite and sauconite. Montmorillonite is the
principle constituent of bentonite clays which have excep-
tionally high watex absorbing and cation exchange properties.
Natural bentonite is a clay mineral consisting
e~sentially o montmorillonite, a complex aluminium sili-
c-~te. This is naturally associated with cations, chiefly
calcium ions but also some sodium ions. Treatment of
natural bentonite may alter the relative proportlons of
the associated cations or introduce new cations, but the
treated products, together with those occuring naturally,
are collectively known as bentonites. We may for example
refer to calcium bentonites, meaning bentonites in which
the associated cations are predominantly but not exclusively
calcium, and sodium bentonites, meaning bentonites in which
such ions are predominantly but not exclusively sodium.
Smectites in solid form are aggregates of very
small particles. In particular, X-ray investigations have
revealed that the elementary unit layer of montmorillonite
consists of three sheets: An octahedral sheet of hydrar-
gillite-brucite included between two tetrahedral sheets of
silicon and oxygen. Exchangeable cations occur between
silica layers. Accordingly the properties of bentonites
and similarly the properties of all smectites are very much
influenced by the nature of the associated exchangeable
- 2 -
~os~s~
cations.
It is known to incorporate smectites, particu-
larly bentonites in fabricated smoking materials - for
example smoking materials in the form of films or other
forms rom which tobacco simulating material can be ob-
tained, but hitherto the incorporation has been carried
out by slurrying solid smectite and all the other ingre-
dients together with water at ambient temperatures and
fabricating the slurry, for example into a ilm. By
these known techniques the smectite in fabricated smoking
materials has not been very finely dispersed, even though
some smectites do disperse in water more easily, relative
to others, for example sodium bentonites disperse more
easily than calcium bentonites.
The degree of disaggregation brought about by
agitating a smectite with water increases with the energy
input. Under standard conditions of rapid agitation a
point is reached where the viscosity reaches a maximum
value. Hereinafter the expression "finely dispersed smec-
tite" refers to a smectite of such fine dispersion as isproduced by agitating it in water at 15C with an input
of 0.04 and preferably 0.08 joules~g/sec until a maximum
viscosity is reached.
The invention provides a fabricated smoking mate-
rial comprising a film~forming binder, inorganlc filler
and a smectite, which smectite is finely dispersed through-
- out the smoking material.
Essential ingredients in the smoking materials
of the invention are the film forming binder, inorganic
filler and smectite but other ingredients may also be in-
-- 3 --
~05~ 8~1
corporated, especially particulate combustible matter.Further possible ingredients are, for example, humectants
e.g. ~lycerol, glycols; glow controlling catalysts e.g.
potassium citrate; colouring matters; flavourants, and
nicotine.
As film-forming binders there may be used cel-
lulose ethers, for example methyl cellulose and especially
carboxymethyl cellulose and its salts. Pectins, starches,
mucilage or natural gums are further examples of film-
~orming binders which may be used.
If desired the film-forming binder may be used
in such proportion as to constitute substantially the
whole of the combustible matter of fuel in the smoking
material. Preferably however, a non~binding uel, especi-
ally a particulate fuel is also used, the main function of
the hinder then being to cause all the ingredients to
adhere sufficiently well for fabrication of the material.
Particulate fuels which may be used include to-
bacco powder; carbohydrates - particularly cellulose; and
20 especially modified carbohydrates, by which we méan carbo- ;
hydrates which have been subjected to a treatment producing
modification of a chemical nature.
Desirably the modified carbohydrate which may be
used is a thermally degraded carbohydrate t especially
thermally degraded cellulose, prepared for example as de-
scribed in our United Kingdom Patent No. 1,113,779 by
subjecting carbohydrate to a catalysed degradation process
at a temperature of 100-250~C until the weight of degraded
material is less than 90% of the dry weight of the original
carbohydrate.
-- 4 --
ll)St~StS i~
The modified carbohydra~e which may be used may
also be a solid condensate prepared by acid or base cata-
lysed condensation of a compound of the formula:
RlCO CH2.CH2 COR~
(or a precuxsor thereof) wherein Rl and R2, which may be
the same or diferent, each represents a hydrogen atom, or
an alkyl, hydroxyalkyl or foxmyl group. Such condensates
in fabricated form are described and claimed in our United
Kingdom Patent No. 1,298,354.
A further example of a modlfied carbohydrate which
may be used is oxidised cellulose made for example as de-
scribed by Kenyon et al ("Industrial and Engineering Che-
mistry", Volume 41, page 2 et seq.).
Smoking materials of the invention containing
high proportions, e.g. from 40 to 65% by weight of inor-
ganic filler are of especial value. Such high proportions
have a beneficial effect in reducing the amount of harm-
ful smoke ingredients reaching the smoker. By appropriate
choice of the inorganic compounds used, acceptable combus-
tion rates may be imparted to smoking mixtures containingfrom 40 to 65% of filler, as is described in our British
Patent-No. 1,299,296. In particular the anions in the
filler may be citrate, formate, oxalate, tartrate, sili-
cate, carbonate, oxide, chloride, sulphate, phosphate or
borate. The cations may, in particular, be sodium, potas~
sium, calcium, magnesium, iron or titanium. Preferred
fillers are magnesium carbonate, basic magnesium carbonate,
calcium borate, sodium borate, sodium chloride, calcium
orthophosphate, calcium oxalate, iron sulphate, titanium
dioxide, alumina, and especially calcium carbonate.
S~;S~8
Th2 following are typical proportions by weight
of the main ingredients of the smoking materials of the
invention :
Film forming10 - 50%
Particulate fuel 0 - 30%
Inorganic filler 40 - 65%
Smectite3-10~, especially 3-7
Other ingredients
(humectants,
flavourants r etc) 0 - 20%
The invention is not however limited to such
proportions.
Smoking mlxtures made according to the process
of the invention are advantageous compared with correspond-
ing mixtures in which smectite is incorporate~ in known
manner~ without being finely dispersed.
In particular cigarettes containing the smoking
materials of the invention produce a more coherent ash
than cigarettes containing the said corresponding mixtures.
This is a discovery of considerable importance in the
development of acceptable tobacco substitutes, for the use
of high filler proportions, although beneficial on health
grounds, leads to the production of flaky non-coherent ash
which is no~iceably different from tobacco ash. This ash
deficiency is noticeable to the smoker even when the to-
bacco substitutes are blended with high proportions of
tobacco.
A further advantage of the smoking materials of
the invention lies in the increased combustion retardant
properties of bentonite when incorporated in dispersed form.
It is therefore possible to avoid or minimise the presence
~os~s~
of other combustion retardants, many of which have unde-
sirable ef~ects upon the smoke. In particular magnesium
carbonate, a known retardant, gives rise to carbon monoxide.
When an inorganic carbonate particularly calcium
or magnesium carbonate is a constituent o~ the inorganic
filler it i5 especially desirabl.e for its surface area in
the dry state to be not greater than 0.6 sq. m/g and more
particularly from 0.2 to 0.3 sq. m/g. In this way the
proportion of combustion retardants other than the bento-
0 nite itself can still further be minimised.An especially pre~erred ~moking material of the
invention, has the ~ollowing final composition:
Film-forming binder 10 - 20%
Particulate fuel, especially
thermally degraded cellulose 20 - 3~%
Calcium carbonate of surface
area 0.05 to 0.6 sq~ m/g, more
parkicularly 0.2 to 0.3 sq. m/g 40 - 50%
Dispersed sodium bentonite3 - 7%
Humectant and any other
ingredlents O - 1û%
- A further feature of the invention provides a
process fox the manufacture of a smoking material rom
ingredients comprising a filler-forming binder, an inorganic
filler and a smectite which process comprises mixing said
ingredients with water, supplying suficient energy during
the mixing operation to cause dispersion of the smectite in
the resultant aqueous slurry and fabricating the resultant
slurry into a form rom which tobacco-simulating material
is obtainable.
In a first embodiment the process of the inven-
tion comprises agitating the smectite on water in water
~ttS ~S ~ ~
with such energy input that the viscosity of the slurry
is not less than that of a slurry produced by agitating the
same smecti-te and water at 15C with an input of 0.0~, pre-
ferably 0.08, joules/g/sec until a maximum viscosity is
reached, combining the slurry with the remaining ingredients
and fabricating the resultant slurry into a form from which
tobacco simulating material is obtainable.
In this embodiment af the proces~ the smectite
is separately dispersed in water by agitation, preEerably
under a sufficiently high energy input to increase the vis-
cosity of the slurry up to the value already indicated. Con-
veniently the other ingredients of the smoking mixture may
be slurried together in conventional manner and combined
with the dispersed smectite. After sufficient mixing to
produce homogeneity the slurry is then fabricated for example
into a filament, tape or sheet. Preferably it is cast into a
thin film and dried to form a sheet. Alternatively a thick
slurry may be extruded to form a filament, tape or sheet.
As a urther alternative a paper making process may be
adopted. The sheet, filament or tape may then be shredded,
- or cut, into a tobacco-simulating form.
Smoking materials made according to the above
embodiment of the pro~cess have a-more coherent and
porous structure than corresponding materials in which the
smectite is incorporated, by known techniques. Accordingly
films of such materials are characterised by lower air
porosity, a parameter which is measurable as described later,
in the introduction to the Examples.
.
~(~Sti~l~8
Desirably the air porosity (measured as described
later) of a film of smoking material according to the
invention O.C5 to 0.2 mm thick should be less than 1000
mlfmin, preferably less than 500 ml/min.
In a second embodiment the process of the in-
vention comprises a~itating the smectite together wi-th othex
ingredients of the smoking material at a tempera~ure above
50C whereby to disperse the smectite on the slurry, and
abricating the resultant slurry into a tobacco simulating
form.
Smoking materials made according to the second
embodiment of the process exhibit porosities which, though
lower than those of corresponding materials made by known
techniques, are generally higher than those of correspond-
ing materials made by the first embodiment. Nevertheless
they are advantageous, like the materials made according
to the first embodiment, in that they produce a more cohe-
rent ash than the known materials, and in that the combus-
tion retardant effect of bentonite, when incorporated in
this way, is increased.
The invention is illustrated but not limited by
the following examples in which all parts and percentages
are by weight.
The commercially available smectites used in the
examples were as follows:
Berkonite*- essentially a calcium bentonite, though a
sodium carbonate treatment is involved in its production
from naturally occurring material.
Aquagel*- a naturally occurring sodium bentonite from U.S.A.
g _
*denotes Trade Mark
S~i5~3~
Fulbent 570*- a sodium bentonite prepared by sodi~ car-
bonate treatment o~ a natural calcium bentonite.
Berkbent C~*- a sodium bentonite prepared by sodium car-
bonate treatment of a natural calci~n bentonite.
_ponite*- a synthetic hectorite product.
Throughout the examples shredded smoking mix-
tures, or blends in 50:50 proportion with tobacco shred,
were used as filliny for l.l g cigarettes 70 mm l~ng and
25 mm in circumference. The cigarettes were smoked on a
standard smoking machine taking 35 ml puffs of 2 seconds
duration every minute. Puf~ numbers were estimated, smok-
ing each cigarette down to a butt length of 20 mm.
Ash cohesion was estimated by weighing on a
microbalance the ash cylinder first falling from the ci-
garette on smoking in a draught-free and vibration-free
enclusure. The total ash obtained by smoking the complete
cigarette was also weighed, and the average ratio of the
weight of the first-falling cylinder to the total ash is
referred to as the bulk ash cohesion value.
Air porosities were measured on a Bendtsen Mark VI
porosity tester, an instrument by which the observed air-
10w through a film can be measured at fixed pressure. Air
porosity figures quoted were measured at an air pressure of
75 mm of water using a 5 cm measuring head, and are ex-
pressed in ml/min.
The thermally degraded cellulose usèd in several
examples was obtained by impregnating cellulose with 7%
ammonium sulphamate solution, compressing so that the cel-
lulose retained its own weight of the solution, drying at
165C and then heating at 265C until a loss in weight of
*denotes Trade Mark
-- 10 --
~05tiS88
25 - 30~ occurred.
EXAMPLES 1 - 3
Dispersion of the bentonites indicated in Table I
was carried out by agitating 5 parts in 95 parts of water
in a recirculating mill (a PUC mill at setting 3) at 45 -
50C until constant viscosity was achieved.
Smoking materials were made hy forming the follow-
ing ingredients into an aqueous slurry, incorporating the
bentonites dispersed as in the previous paragraph casting
the slurry on to a`band drier to give a film with a drybasis weight of 48 - 52 g/sq. m and drying and shredding
the ilm so obtained. This material was blended in 50:50
proportion with tobacco shred:
Thermally degraded cellulose 26.9 parts
Glycerol . 6.0
Calcium carbonate 45.1 "
Ammonium sulphate 2.0 "
Sodium carboxymeth~l cellulose 15.0
Bentonite 5.0
Cigarette tests on the blends, and on comparative
blends made by incorporating dry bentonite in the slurries
are indicated in Table I, which also includes determinations
of air porosity on the films.
-- 11 --
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5i31~
E~MPLES 4 and 5
Dispersion of the bentonites indicated in Table
II was carried out by agitating 5 parts in 95 parts of
water at 45 - 50C with a low shear turbine impeller (power
input 0.007 joules/g/sec. until a maximum viscosity had
been achieved.
Smoking mixtures were made by forming the fol-
lowing ingredients into an aqueous slurry, incorporating
the bentonites dispersed as in the previous paragraph,
casting the slurry on to a band drier to give a film with
a dry basis weight of 48 - 52 g/sq. m and drying and shred-
ding the film so obtained.
This material was blended in 50:50 proportion
with tobacco shred:
Thermally degraded cellulose 26.9 parts
Glycerol 6.0 ~'
Calcium carbonate (marble) 47.1 "
Sodium carboxymethyl cellulose 15.0 "
Bentonite 5,0 "
Cigarette tests on the blends, and air porosity
determinations on the films are indicated in Table II.
TABLE II
Bxample Bentonite* Bulk Ash Puff No. Air Poro-
_ (dispersed) Cohesion _ sity ml/min
4 Fulbent 570* 61.2 10~2 850
Aquagel* 67.2 9.9 - 75
.
EXAMPLES 6 to 10
In these examples the bentonites indicated in Table
III were dispersed in slurries of the other smoking mixture
ingredients by stirring at 55 - 65C. The slurries were
*denotes Trade Mark
- 13 -
~)5~58~
cast ^n to a band drier to give a fil~ with a dry basis
weight Qf 48 - 52 g~sq. cm and the ~ilm dried and shredded.
The composition of these films wàs ~:-
Thermally degraded cellulose27 parts
Glycerol 6 "
Calcium Carbonate 17 "
Magnesium carbonate 29 "
An~onium sulphate 2 "
Sodium carboxymethyl cellulose15 "
Bentonite 4 "
Two series of films were made:-
(a) using coarse calcium and magnesium carbonates
having an average surface area of Q.25 m2/g aetermined by
the air permeability method described by P.J. Rigden in
"Journal of the Society o Chemical Industry" 1943 papers
1 to 4.
(b) using ordinarily available ~inely divided
calcium and magnesium carbonates, of average surface areas
0.87 m /g.
50:50 Blends of the shredded films and tobac-
co shred were packed into cigarettes and tested as indicated
above~ The test results are given in Table III.
- - - 14 - -
~05~8~
. o ~ o o o o o o
O ~ L~ Lr) o ~r Ln o
oo u~
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1r~5~
EX~PLE 11
A smoking material was made by slurrying the
following ingredients in water at 65C, casting into a
film and drying:-
Thermally degraded cellulose27 par-ts
Glycerol 6 "
Calcium carbonate 15.5 "
Magnesium carbonate 26.5 "
Ammonium sulphate ` 2
Sodium carboxymethyl cellulose 15 "
Berkbent CE* 8 "
For comparison an identically constituted
smoking material was made by slurrying at 28C.
Similarly comparative materials were made with-
out the Berkbent CE*, the calcium and magnesium carbonate
proportions being adjusted to maintain a constant ratio
of calcium to magnesium.
Each shredded film was blended with tobacco in
50:50 proportion and cigerettes packed with the blend
were tested as indicated above. Test results were given
in Table IV.
- TABLE IV
Example Slurry Temp. Puff No. .
_ .. . ,
11 60C 12.1
Comparative 28C 11.0 .
Comparative 60C 11.1
No Berkonite CE*
Comparative 28DC 10.6
No Berkonite CE* .
*denotes Trade Mark
- 16 -
~LO~S8i~
EXAMPLE 12
.
A smoking material was made by slurrying the
following ingredients in water at 60C, casting into a
film and drying:-
Sodium carboxymethyl cellulose30 parts
Glycerol 6 "
Calcium carbonate 28 "
Perlite 28 "
Berkben~ CE* 8
For comparison an identically constituted
smoking material was made by slurrying at 28C.
Each shredded film was blended with tobacco
in 50:50 proportion and cigarettes packed with the blend
were test smoked as indicated above. Test smokings were
also made on cigarettes packed with 100% shredded film.
Results are given in Table V.
TABLE V
Example ISlurry Temp. :Puff No. Puff
50;50 blsnd 100%
_ .
.12 60C 10.2Glow-
2~ .proofed
i Com~arative 28C 9.5, . 7.2
EXAMPLE 13
A smoking material was made by slurrying the
following ingredients in water at 60C, casting into a
film and drying:-
Thermally degraded cellulose 27 parts
Sodium carboxymethyl cellulose 15 "
Glycerol 6 "
- Calcium carbonate 16 "
Perlite (Celite PFl grade)* 28
Berkbent CE* 8 "
*denotes Trade Mark
- 17 -
For comp~xison an identically constitute~ smoking
material was mad~ by slurrying at 2~C.
Each shredded ~ilm was blended with tobacco in
50:50 proportion and cigarettes packed wi~h the blend
were test smol,ed as indicated above, Test smokings were also made
~n cigarèttes packed with 100% ~hredded film. ~esults are given
in Table VI.
TABLE VI
~ . ~
Example Slurry Temp, Pu~f ~o. Puf ~.
~50:50 blend) 100%
_ . .... _
13 60C 10,5 8.
~o~r~ti-e 28C 9.3 7.6
EXAMPLE 14
A smoking material was made by slurrying ~he
following ingre~i~nts in water at 60C, ca~ti~g into a fi~m
j and drying:- .
Thermally degraded cellulose 27 parts
- Glycerol - 6 parts
Calcium Sulphate ~2 parts
~mmonium Sulphate .2 parts
2~ Sodium carboxymethyl cellulose 15 parts
Berkbent CE* 8 parts
For c~mpa~ison an identically constituted smoking
mixture was made by slurrying at 28Co
Bach shredded film was blended wi~h tobacco in
50:50 proportion and cigarettes packed with the blend were
test smoked as inaicated aboveO Results are given in
Table VII,
TABLE VII
j Example Slurry temp j Puff No
14 60 C 14r2
Comparative 28C 1307
-18-
. *denotes Trade Mark
~s~
EXP~IPLE 15
An aqueous dispersion was made by vigorously
agitating 3 parts of Laponite* in 97 parts of water at
45 - 50C until constant viscosity was achieved.
A smoking material was made by forming the
following ingredients into an aqueous slurry, incorporat-
ing the Laponite* as a dispersion and casting the sIurry
onto a band dryer to ~ive a film.
For comparison an identicall~ constltuted
smoking mixt~re was made, introducing the Laponite* as a
dry powder into the slurry,
Each shredded fi~m was blended with tobacco in
50:50 proportion and cigarettes packed with the blend
were test smoked as indicated above. Test smokings were
; also made on cigarettes packed with 100% shredded film.
- Results are given in Table VIII.
TABLE VIII
, - ~ . _ . _ . .
Example Puff ~o. Pu~f ~o.
_ (50:50 blend) _ (100%)
20 15 11.9 12.4
Comparative _ 11.5 _9.5 _
*denotes Trade Mark
--19--
