Note: Descriptions are shown in the official language in which they were submitted.
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D E S C R I P T I O N
LOW FLAME-SPREADING CIGARETTE PAPER
Technical Field
The present invention relates to a low flame-
spreading cigarette paper, and particularly, to a
cigarette paper exhibiting both a low flame-spreading
property and a low C/T ratio.
Background Art
For example, a cigarette paper provided with bands
formed of a flame retardant substance coated on a base
cigarette paper is proposed (Jpn. Pat. Appln. KOKAI
Publication No. 7-300795), in order to hardly cause the
flame to spread from the kindling to, e.g., the floor
when the cigarette is dropped on the floor through, for
example, the carelessness of the smoker. This
technique is based on the idea that when regions having
a high combustibility and regions having a low
combustibility are formed on a cigarette paper, the
ordinary smoking can be performed at the region having
a high combustibility, but, if a substance is brought
into contact with the cigarette at the regions having a
low combustibility, the cigarette is self-extinguished.
However, where a cigarette is manufactured by
using the conventional low-flame spreading cigarette
paper noted above, the carbon monoxide/tar ratio
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(C/T ratio) per cigarette is not sufficiently low.
Disclosure of Invention
Therefore, it is an object of the present
invention to provide a cigarette paper exhibiting a low
flam-spreading property and achieving a low C/T ratio.
According to the present invention, there is
provided a cigarette paper exhibiting a low flame-
spreading property, comprising, on one surface of a
base cigarette paper containing a filler in an amount
of 2 to 6 g/m2 and having a basis weight of 16 to
22 g/m2, burn-suppressing regions coated with a burn-
suppressing agent, provided spaced apart from each
other, wherein a total coating amount of the burn-
suppressing agent corresponds to 0.2 to 1.8 g per m2 of
the coated portion.
Brief Description of Drawings
The single figure is a schematic oblique view,
partly broken away, exemplifying a construction of a
cigarette wrapped with a cigarette paper according to
one embodiment of the present invention.
Best Mode for Carrying Out the Invention
The present invention will now be described in
more detail.
>
In the cigarette paper of the present invention,
burn-suppressing regions coated with a burn-suppressing
agent are formed apart from each other on one surface
of a base cigarette paper.
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The base cigarette paper is based on an ordinary
pulp such as flax pulp that is generally used for
cigarette papers. However, the base cigarette paper
contains a filler in an amount of 2 to 6 g/m2, and has
a basis weight of 16 to 22 g/m2.
As the filler, use may be made of materials that
are used generally including, for example, carbonates
such as calcium carbonate and potassium carbonate, and
hydroxides such as calcium hydroxide and magnesium
hydroxide.
A burn adjusting agent such as citric acid or a
salt thereof (sodium salt or potassium salt) may be
added to the cigarette paper. These burn-adjusting
agents, if added, may be used in an amount of up to 2%
by weight in the base cigarette paper.
On one surface of the base cigarette paper, burn-
suppressing regions, which are formed by coating of a
burn-suppressing agent, are provided apart from each
other. The burn-suppressing regions may be provided in
the form of a plurality of stripes such that when a
tobacco rod is wrapped with the cigarette paper, they
extend in the longitudinal direction of the tobacco rod
and are spaced apart from each other in the
circumferential direction of the tobacco rod.
Alternatively, the burn-suppressing regions may be
provided in the form of a plurality of annular rings
such that they extend in the circumferential direction
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of the tobacco rod and are spaced apart from each other
in the longitudinal direction of the tobacco rod. In
any case, the total coating amount of the burn-
suppressing agent (dry basis) corresponds to 0.2 to
1.8 g/m2 per m2 of the coated region.
As the burn-suppressing agent, use may be
preferably made of, for example, proteins such as
gelatin, casein, albumin, and gluten; polysaccharides
exhibiting a viscosity-increasing property such as
starch, xanthan gum (echo gum), locust bean gum, guar
gum (guar pack), tragacanth gum, tamarind seed
polysaccharide (glyroid), karaya gum, gum arabic,
pullulan, dextrin, cyclo dextrin (Oligoseven), and
gutty; polysaccharides exhibiting a gelling property
such as carrageenan, curdlan, agar-agar, gelatin,
farselran, pectin, juran gum, and Kelco Gel; a lipid
such as lecithin; natural polymer derivatives such as
sodium alginate, carboxymethyl cellulose, methyl
cellulose, propylene glycol alginate ester, and
processed starch (such as starch phosphate);
synthesized polymeric compounds such as sodium
polyacrylate and various polymeric emulsifying agents;
inorganic ammonium salts such as ammonium chloride,
ammonium phosphate, ammonium hydrogen phosphate,
ammonium dihydrogen phosphate, ammonium bromide and
ammonium sulfate; inorganic hydroxides such as barium
hydroxide, calcium hydroxide õ and aluminum hydroxide;
CA 02599753 2007-08-31
an inorganic salt flame retardant such as sodium
borate, boric acid, zinc chloride, magnesium chloride,
calcium chloride, and sodium sulfate. Also, finely
pulverized cellulose, microcrystalline cellulose, flax
5 pulp, and wood pulp have similar effects. These burn-
suppressing agents can be used singly or in combination
of two or more of these. Sodium alginates having
various degrees of polymerization are commercially
available. In the present invention, sodium alginate
having a polymerization degree of 500 to 900 is
preferred. Sodium alginate having such a high degree
of polymerization exhibits a high burn-suppressing
effect even when used in a small amount.
In the present invention, the low flame-spreading
property and the low C/T ratio can be exhibited at the
same time by setting the amount of the filler in the
base cigarette paper, the basis weight of the base
cigarette paper, and the total coating amount of burn-
suppressing agent within the ranges described above.
The low flame-spreading cigarette paper of the
present invention is used to wrap a tobacco rod formed
of, for example, tobacco shreds, and generally, the
surface on which the burn-suppressing agent is coated
is brought into contact with the tobacco rod.
FIG. 1 illustrates a cigarette wrapped with a
cigarette paper on which a burn-suppressing agent is
coated in the form of annular rings.
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Referring to FIG. 1, a cigarette 10 comprises a
tobacco rod 11 consisting of a tobacco filler 13 that
is wrapped with a base cigarette paper 12 in the form
of a column. The base cigarette paper 12 may have an
inherent air permeability of about 10 to 100 CORESTA
units. In general, the tobacco rod 11 has a
circumference of 17 to 26 mm and a length of 49 to
90 mm. An ordinary filter 18 may be attached to the
proximal end portion (i.e., downstream edge portion in
the inhaling direction) of the tobacco rod 11 by using
a chip paper 17 according to the ordinary method.
An annular region 14 coated with a burn-
suppressing agent is formed on the base cigarette paper
12, defining a burn-suppressing region. Where a
plurality of annular burn-suppressing regions 14 are
formed as illustrated in FIG. 1, these annular regions
14 are formed apart from each other in the longitudinal
direction of the tobacco rod.
An ordinary burn region 15 that is not coated with
a burn-suppressing agent is formed between adjacent
annular burn-suppressing regions 14. Since the
region 15 is constituted by a part of the base
cigarette paper 12, it can burn under the ordinary
smoking state like the base cigarette paper 12 itself.
It follows that the region 15 acts as an ordinary burn
region. For example, it is possible to form 1 to 3
annular burn-suppressing regions 14. Also, the annular
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burn-suppressing region 14 may have a width of 4 to
7 mm in the longitudinal direction and generally have a
thickness of 0.1 to 5 m. Where a plurality of burn-
suppressing regions 14 are formed, distance between the
adjacent burn-suppressing regions 14 is preferably 18
to 25 mm.
In the cigarette shown in FIG. 1, a region 16
covering a distance d from the tip is not coated with a
burn-suppressing agent. This section at the tip
portion, which is not coated with the burn-suppressing
agent, also constitutes an ordinary burn region, and
can correspond to the region that is combusted by one
puff or two puffs in the ordinary cigarette.
Incidentally, where a plurality of burn-suppressing
regions 14 are provided, the ordinary burn region 16
may not be formed (d = 0). However, where a single
burn-suppressing region 14 is provided, the distance d
from the tip lla of the tobacco rod can be set at 10 to
mm. It is not particularly necessary to form a
20 burn-suppressing region 14 on the inner surface of the
cigarette paper corresponding to that portion of the
cigarette paper 12 which is covered with the chip paper
17.
When the cigarette 10 is ignited at the tip lla
25 and inhaled to be burnt, the cigarette can burn at the
ordinary burn region 15 like an ordinary cigarette and
the flavor and taste can be enjoyed. However, if the
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cigarette 10 under the ignited state is put on a
combustible material such as a carpet, a tatami mat, a
wooden article, cloths, or clothing, the burn-
suppressing region 14 extending in the combusting
direction, the heat absorption by the combustible
substance, and the expanded tobacco shreds collectively
serve to extinguish the cigarette 10, and prevent the
combustible substance from catching fire. Also, the
cigarette wrapped with the cigarette paper of the
present invention is low in the C/T ratio in the
mainstream smoke.
The present invention will be described by way of
Examples below. However, the present invention is not
limited by these Examples.
Examples 1 to 13 and Comparative Examples 1 to 12
A base paper (width 27 mm; length 1.500m) of the
specification shown in Table 1 was coated (printed)
with an aqueous solution of sodium alginate of various
concentrations (0.5 to 20% by weight) at a constant
width of 7 mm in the longitudinal direction and a
constant spacing of 20 mm in the form of stripes by a
direct gravure method, forming a total of 56 burn-
suppressing agent-coated regions. For the cigarette
paper'thus obtained, the total coating amount of sodium
alginate was measured according to the procedures
described below. The results are shown also in Table
1. As shown in Table 1, the total coating amount of
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the burn-suppressing agent per m2 of the region coated
with the burn-suppressing agent (sodium alginate)
corresponded to 0.2 to 1.8g in the papers of Examples 1
to 13. This coating amount of the burn-suppressing
agent can be converted to the amount of the burn-
suppressing agent per area of the cigarette paper by
being multiplied by 7/27, yielding 0.05 to 0.47 g/m2.
Incidentally, sodium alginate used in each of Examples
5, 8 and 11 was I-S manufactured by KIMIKA (registered
trademark) (polymerization degree: 650 to 670;
viscosity of its 3% by weight aqueous solution at 25 C:
29976.9 cP), and sodium alginate used in each of the
other Examples was IL-2 manufactured by KIMIKA
(registered trademark) (polymerization degree: 30 to
180; viscosity of its 3% by weight aqueous solution at
C: 907.2 cP) .
A tobacco rod consisting of American blend of
tobacco shreds (tar amount without a filter: 19 to
20 mg) was wrapped with the cigarette paper obtained
20 above, and was cut such that the first coated region
was arranged 5 mm spaced apart from the burn edge of
the cigarette. Each cigarette was 59 mm long, and had
two burn-suppressing agent-coated regions.
The cigarette thus obtained was subjected to a
25 burn test in accordance with ASTM E-2187-04 so as to
measure the value of PFLB (percent full-length burn).
Also, the CO amount in the mainstream smoke, the number
CA 02599753 2007-08-31
of puffs and the tar amount for each cigarette sample
were measured by the methods described below in respect
of these cigarette samples. The results are shown in
Table 2.
5 <Measurement of Total Coating Amount of Sodium
Alginate>
Measurement was made as follows in accordance with
"Quantitative Analytical Method of Sodium Alginate in
Food" described in "Food Hygienics Magazine", Vol. 5,
10 pp. 297-302 (1988), without carrying out the
degreasing, the treatment with a dilute sulfuric acid,
and the protein-removing treatment.
The cigarette paper coated with the burn-
suppressing agent (1.5000m; width 27 mm) (about 1.Og)
was cut into pieces each sized at 5 mm square. Then,
40 mL of a 1% by weight aqueous solution of sodium
hydrogen carbonate was added thereto, and heated for
5 minutes in a warm water bath at 60 C. Then, the
mixture was sufficiently mixed, stirred, and subjected
to centrifugal separation (3,500 rotations, 10 minutes;
the same applies to the following) to give a
supernatant liquor (extracted liquid). The extraction
residue was similarly subjected again to the extraction
to give a supernatant liquor (extracted liquid). In
addition, 20 mL of a 1% by weight aqueous solution of
sodium hydrogen carbonate was added to and mixed
sufficiently with the extraction residue to give
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supernatant liquor (extracted liquid). These three
extracted liquid were combined, and a 1% by weight
aqueous solution of sodium hydrogen carbonate was added
to 100 mL, which was used as a test solution.
2 mL of copper-hydrochloric acid solution (8.5M
hydrochloric acid containing 0.05% by weight of copper
sulfate) and 1 mL of a naphtoresorcinol solution (0.4%
by weight aqueous solution of 1,3-dihydroxynaphthalene)
were added to each of 1 mL of a sodium alginate
standard solution (1% by weight aqueous solution of
sodium hydrogen carbonate containing sodium alginate at
a concentration of 0 to 0.2 mg/mL) and 1 mL of the test
solution noted above. Then, each mixture was heated
for 65 minutes in a boiling water bath, and then cooled
in ice water, to which 4 mL of butyl acetate was added.
The mixture was shaken and subjected to centrifugal
separation.
1 mL was taken from the supernatant liquor after
the centrifugal separation, diluted by adding 3 mL of
butyl acetate and subjected to a colorimetric at
566 nm, and the total coating amount was calculated.
<Measurement of CO Amount and the Number of Puffs>
For measuring the CO amount, the tobacco smoke was
collected by using an 8-port linear smoking machine (SM
342) manufactured by FILTRONA Inc. For the burn of the
cigarette, the suction of 35 mL/2 seconds was carried
out at an interval of 60 seconds according to the ISO
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standards, and the smoke passing through the glass
fiber filter was collected in a gas bag. The suction
of the cigarette sample was stopped when the sample
reached the standard burn length (51 mm from the
ignition edge of the cigarette (8 mm apart from the tip
side as measured from the boundary between the
cigarette paper and the chip paper)). The number of
puffs at this point was counted and recorded. After
the burning, the igniting portion was removed and,
then, blank puffing was performed three times so as to
collect the gas remaining in the cigarette. In this
fashion, the gas of the cigarette sample was collected
in the gas bag, and the total particulate matter (TPM)
was collected at the glass fiber filter.
The CO amount per cigarette sample was measured
with a CO measuring apparatus manufactured by FILTRONA
Inc., using the gas collected in the gas bag and
<Measurement of Tar Amount>
From the particulate components collected at the
glass fiber filter in measuring the CO amount, the
crude tar amount was weighed, and then the filter was
put in a serum bottle and vigorously shaken together
with 10 mL of 2-propanol (GC grade, manufactured by
Wako Junyaku K.K.). The extracted liquor was filtered
and poured into a vial. Then, the extracted liquor was
applied to a chromatograph so as to measure the water
amount and the nicotine amount. The quantitative
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determination was carried out by the internal standard
method, and the tar amount was obtained by subtracting
the water amount and the nicotine amount from the crude
tar amount.
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16
From the results shown in Table 2, it can be seen
that the cigarette papers (Examples 1-13) in which a
burn-suppressing agent is coated spaced from each other
on a base cigarette paper containing a filler in an
amount of 2 to 6 g/m2 and having a basis weight of 16
to 22 g/m2 such that the total coating amount
corresponds to 0.2 to 1.8 g/m2 exhibit a low flame-
spreading property and a low C/T ratio.
As has been described above, the present invention
provides a cigarette paper which exhibits a low flame-
spreading property and achieves a low C/T ratio.
