Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Filter unit for filter-cigarettes and filter cigarettes
The present invention relates to a filter unit for reducing the tar and
nicotine
content of the smoke of cigarettes containing a tobacco body and a filter tip.
Furthermore the invention relates to cigarettes containing filter unit.
The tobacco industry makes efforts all over the world to sell tobacco products
with the possibly lowest tar and nicotine content with preserving, at the same
time, their delight value. In the USA and in Europe, there are statutory
regulations putting a ban from 2004, on cigarette products with tar content
exceeding 10 mg.
The tobacco raw material is grown in improved breeding in order to obtain a
plant with increased aroma, resin and sugar content at the lowest harmful
nitrogen compound content and, at the same time, plants with finer leaves.
After harvesting the leaves, the tobacco is fermented, in which process .the
tobacco heats up, its weight decreases and changes caused by enzymes and
bacteria occur. The fermented tobacco is processed to tobacco products:
cigars, cigarettes and cigarette- or pipe-tobacco.
The two most harmful components of tobacco smoke are nicotine and tar. At
smoking, they get into the human organism where they deposit and absorb,
exerting there their heavily harmful influence on health.
The main alkaloid of tobacco is nicotine, but in its leaves, it contains a
series of
other chemically related compounds. At smoking, about 30-60% of the nicotine
content gets into the smoke, and 20-90% of this amount is absorbed in the
human organism, depending on the mode of smoking, whether it occurs fast or
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slowly, or whether the smoke is inhaled directly into the lungs. In spite of
its
harmful and toxic effect, the delight of smoking is provided by nicotine.
However, a more serious danger than nicotine is for human organism and for
human health the tar present in smoke, as it contains carcinogenic substances
(e.g. benzpyrene). Passive smokers are subjected involuntarily to coexistence
with tobacco smoke, thus smokers damage not only themselves, but also
people living in their surrounding as well. Therefore solutions should be
searched for a significant reduction of these dangers.
Numerous smoke filters have been developed for reducing the amount of
nicotine, and especially tar, present in cigarette smoke introduced into human
organism. They may be filters containing additives (e.g. active carbon,
charcoal), promoting ventilation or heating, or filters suitable for
dispersing
smoke. Such are described e.g. in US patents No. 3,958,579; 3,882,877;
3,762,422; DE-OS 29 02 120 and DE-OS 23 56 569. Their common draw-back
is that the air resistance is significantly increased by the filter and thus
their
smoking is rather difficult. Further on, they impair the aroma of the tobacco,
the
habitual character of the cigarette has changed. In this way, a cigarette with
a
new nature and an impaired delight value was received from the traditional
cigarette of known and enjoyed characteristics.
Last but not least, applying such amendments in an existing production
technology is rather complicated and expensive due to the necessary change
of the whole machinery. Thus, these solutions would mean only a disadvantage
for the tobacco industry.
The object of the present invention is to develop a filter unit which is
applicable
in cigarettes provided with filter-tip, the production of which can be fitted
into
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traditional production technology, in a way that the original nature of the
cigarette, its smokability, aroma and delight value remain and, at the same
time, the carcinogenic tar and nicotine content of the smoke is reduced
significantly.
Accordingly, the filter unit contains wood cuttings of particle sizes of 0.2 -
1.2
mm impregnated with sodium chloride, preferably with a solution of 20-40 % of
sodium chloride and 80-60 % of water. The wood cuttings may be present
loose, or alternatively, applied on a strip made of cellulose-acetate.
It should be noted that the wood cuttings should preferably be in a loose
form,
as the cellulose-acetate strip has been proven to be carcinogenic, similarly
to
all other filter-tips with additional filters. At every puff, together with
the smoke,
some of the cellulose-acetate gets into the lung, and may cause lung cancer by
accumulating there.
The filter unit according to this invention contains natural and harmless
materials instead of the harmful and carcinogenic cellulose-acetate, in
addition
to its capacity for the significant reduction of the amount of carcinogenic
tar
and toxic and harmful nicotine.
The filter unit can be applied between the tobacco body and the filter tip, or
between two parts of the filter tip, and can be separated from the filter by a
closing web.
Wood cuttings alone are capable of some filtering. However, they become an
excellent adsorber upon impregnating them by sodium chloride. The big
surface area of the impregnated wood cuttings becomes porous after drying,
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due to the presence of sodium chloride crystals, further increasing thereby
the
original surface area.
Wood cuttings impregnated with sodium chloride solution as filter perform
increased physical filtering of the cigarette smoke due to the increased
crystalline and porous surface. it, The tar and nicotine content of the smoke
can deposit on and adhere to an increased surface area when the cigarette
smoke passes through.
On the other hand, the sodium chloride solution increases the filtering effect
not only by increasing the surface area, but also by forming a crystallized
film
capable of dissolving and crystallizing again and again. The crystalline
sodium
chloride becomes a good adsorbent when it gets into contact with the hot and
moistureous cigarette smoke, and its surface becomes activated by some
dissolution and softening. Than, the tar and nicotine particles adhere to its
surface, then penetrate into the filtering medium. At the time the hot and
moistureous smoke leaves the filter, the slightly heated sodium chloride cools
down and crystallizes, adsorbing thereby the tar and nicotine therein. At
every
new puff the adsorption is repeated.
In addition, the filter unit according to the invention directs the smoke
passing
through it to the whole surface area of the filter and distributes it on the
surface
uniformly. Thus, the whole surface area is utilized and the efficiency
increases.
In traditional filters, filtering occurs only on part of the surface, since
the air-
smoke mixture swirls to the central part of the filter and the deposition and
adsorption of tar and nicotine concentrates on this part.
The use of wood cuttings is advantageous as it is a waste material, it is
cheap
and it is a natural substance (which is important in view of environmental
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protection). Its weight is also small: the weight of the filter unit made of
it does
not reach the weight of the charcoal filter applied on a cellulose-acetate
tape
used world-wide in filter cigarettes. It is a soft material, thus it can be
fitted into
every technology of cigarette and filter manufacture, and due to its polygonal
5 shape, it has a large surface area. Further on, its structure is fibrous
and,
owing to all this, it has a very high adsorption capacity.
The sodium chloride solution can be absorbed and it can impregnate the wood
cuttings. After drying, the thin film forms a crystalline and porous surface,
the
unevennesses of which increase the whole surface area, increasing thereby
the filtering capacity. At contacting with the hot and moistureous air, the
surface
gets slightly dissolved and softened, and as a result, the microparticles of
tar
and nicotine adhere to the surface immediately. After cooling, the sodium
chloride solution crystallizes, gets solid and porous again.
By applying the filter unit according to the invention, the tar content of
cigarette
smoke can be reduced by 10-30%, whereas its nicotine content by 12-32%,
depending on the nature and quality of the tobacco, on the length of the
cigarette body, without influencing or changing the aroma, delight value and
character of the cigarette.
Further details of the invention will be explained by examples, with reference
to
the enclosed drawings.
Figure 1 is the longitudinal section of a cigarette provided with a filter
unit
according to the invention;
Figure 2 is the cross-section of a filter unit;
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Figure 3 is the cross-section of another embodiment of the filter unit;
Figure 4 is the section of another embodiment of a cigarette provided with a
filter unit according to the invention.
Figure 1 shows the longitudinal section of a filter-tip cigarette. Body 1 of
the
cigarette consists of tobacco 3 covered by cigarette paper 2, while filter tip
4
contains the traditional filtering element: a helically wound strip. Filter
unit 5
according to the invention is arranged between body 1 and filter tip 4. They
are
separated by a web 6.
Cross sections of the two embodiments of filter unit 5 are shown in Figures 2
and 3.
In the embodiment shown in Fig. 2, the structure of filter unit 5 is similar
to that
of filter tip 4. The wood cuttings 9 according to the invention are spread on
the
surface of a helically wound acetate strip 8 in paper covering 7.
In the embodiment shown in Fig. 3, wood cuttings 9 are arranged loose in
paper covering 7. Their spillage is hindered in both cases by web 6 shown in
Fig. 1.
The filter unit according to the invention can be arranged not only between
the
cigarette body 1 and the filter tip 4, but also within the filter tip 4.
Figure 4
illustrates an embodiment in which fitter tip 4 is separated into two parts,
and
the filter unit 5 according to the invention is inserted between these two
parts.
Between filter unit 5 the right part of filter tip 4 there is a web 6.
In the following, the invention will be explained more in details by examples.
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In Tables 2-5, the tar and nicotine contents of a traditional filter-tip
cigarette
and those of cigarettes provided with the filter unit according to the
invention
will be compared. Tests have been performed on cigarettes according to Table
1. different embodiments of filter units according to the invention have been
built into this cigarette, and the original cigarette has been used as
control.
Characteristics of the original cigarette were the following:
Table 1
Full length of the cigarette 98.6 mm
Body length 72.6 mm
Filter length 26.0 mm
Diameter of the cigarette 7.9 mm
Total weight 1.1153 g
Tar content 0.5 mg
Nicotine content 0.93 mg
The tests have been carried out by a routine analytical cigarette smoking
machine according to the following standards:
- ISO 3308 (smoking)
- ISO 4387 (determination of the total and nicotine-free dry material by using
routine analytical cigarette smoking machine)
- ISO 10 315 ( determination of the nicotine content in smoke condensates of
cigarettes by gas chromatography)
- ISO 10362-2 (determination of water in smoke condensates of cigarettes by
the Karl Fischer method).
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In Table 2, results are shown for the embodiment containing the filter unit of
cigarettes shown in Fig. 1, in which the impregnated wood cuttings were
applied onto an acetate strip shown in Fig. 2. The wood cuttings have been
impregnated with a solution of 20% NaCI and 80% water.
Table 2
Control Invention
Tar (mg/cigarette) 11.5 9.22
Nicotine (mg/cigarette) 0.93 0.79
Tar reduction (%) 12.2
Nicotine reduction (%) 15.12
Table 3 shows the results for samples made according to Fig. 1 as well, but
the
wood cuttings in the filter unit were loose.
Table 3
Control Invention
Tar (mg/cigarette) 10.5 9.0
Nicotine (mg/cigarette) 0.93 0.77
Tar reduction (%) 14.28
Nicotine reduction (%) 17.20
Samples in Table 4 were prepared according to the embodiment shown in Fig.
4; the filter unit consisted of acetate strip according to Fig. 2.
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Table 4
Control Invention
Tar (mg/cigarette) 10.5 9.34
Nicotine (mglcigarette) 0.93 0.80
Tar reduction (%) 11.10
Nicotine reduction (%) 14.02
Samples in Table 5 were prepared according to Fig. 4, the filter unit in them
contained loose, impregnated wood cutting particles.
Table 5
Control Invention
Tar (mg/cigarette) 10.5 9.10
Nicotine (mg/cigarette) 0.93 0.78
Tar reduction (%) 13.40
Nicotine reduction (%) 16.32
It is well seen from the Tables that the filter unit according to the
invention
reduces the tar and nicotine content of cigarette smoke in each case. At the
same time, the smoke distribution became more uniform and, as a
consequence, the efficiency of the filter was increased.
In the case of cigarettes tested, the density (0.4 g/cm3) and weight (0.25 g)
of
the filter unit met the requirements applied in the known filter-tip
manufacturing
technologies and were about the minimum values of density and weight
allowed for the technology used for the tests, while the corresponding
reduction
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in tar and nicotine content was between 10 and 20 %. At the same time, the
delight value of the cigarette and the air resistance of the filter did not
increase
with respect to the control samples.
According to the technology applied nowadays throughout the world, the
density and weight of the filter unit according to the invention can be
increased,
thus the amount of tar and nicotine filtered out can also be increased. By
increasing the compactness of the filter unit (which must not exceed the
compactness of the tobacco chippings in the body), as well as by increasing
the size of the filter unit, the tar and nicotine content can be further
decreased
without changing the delight value of the cigarette or increasing the air
resistance of the filter, i.e. the smokability of the cigarette was not
deteriorated.
The embodiments shown in the examples illustrate the invention only, and the
cigarettes can be prepared in numerous other versions within the scope
claimed.
