Technical Field
[0001] The present invention relates to a cigarette filter and a cigarette comprising the
same.
Background Art
[0002] Many cigarettes comprise filters to remove various components in cigarette mainstream
smoke. As the filter, a filter having a cellulose acetate fiber tow as a filter material
is widely used.
[0003] The acetate filter is known to have selective filtering characteristics such that
the filtration efficiency of semivolatile components is higher than the filtration
efficiency of tar in cigarette mainstream smoke. The semivolatile component is a component
present in both the particulate and vapor phases of cigarette mainstream smoke, and
includes a nitrogen-containing compound, ketones, and phenols. These semivolatile
components have an effect on cigarette smoking taste, and thus it may be desired that
the components are not significantly removed by the filter.
[0004] Patent Document 1 discloses a tobacco smoke filter which is substantially formed
of cellulose acetate microfilaments having an average diameter of 20 to 250 µm as
a tobacco smoke filter for removing harmful components from tobacco smoke. Patent
Document 1 also discloses that the microfilaments are mixed with a normal cellulose
acetate fiber tow. However, Patent Document 1 does not teach of the semivolatile components,
though it discloses that the filter is excellent in removal efficiency of tar in tobacco
smoke.
Prior Art Document
Patent Document
[0005] Patent Document 1: Jpn. Pat. No.
3939823
Summary of Invention
Problem to be solved by the Invention
[0006] An object of the present invention is to provide a cigarette filter which does not
significantly remove a semivolatile component in cigarette mainstream smoke and a
cigarette comprising the same.
Means for solving the Problem
[0007] In order to solve the above problem, according to the first aspect of the present
invention, there is provided a cigarette filter comprising a filter plug that includes
a filter material containing:
a cellulose acetate fiber tow, and
filtration rate control particles dispersed in the tow and selected from cellulose
particles, cellulose triacetate particles and a mixture thereof.
[0008] According to the second aspect of the present invention, there is provided a filter-tipped
cigarette comprising:
a cigarette rod; and
the cigarette filter of the present invention which is attached to the end of the
cigarette rod.
Effects of the Invention
[0009] The cigarette filter of the present invention does not significantly remove the semivolatile
component in cigarette mainstream smoke.
Brief Description of Drawings
[0010]
FIG. 1 is an enlarged schematic view showing a part of a cigarette comprising a filter
according to one embodiment of the present invention.
FIG. 2 shows graphs showing relationships between the draw resistance of the control
filter and each of the permeability of tar, nicotine, and typical semivolatile components
in mainstream smoke.
FIG. 3 shows graphs showing relationships between the draw resistance of the filter
according to the present invention and each of the permeability of tar, nicotine,
and typical semivolatile components in mainstream smoke.
FIG. 4 is a graph showing a relationship between the selective filtration coefficient
Sx and the draw resistance of the filter according to the present invention together
with that of the control filter.
FIG. 5 is a graph showing a relationship between a plasticizer (triacetin) to be added
to a filter material and the permeability of typical semivolatile components.
FIG. 6 is a graph showing a relationship between the draw resistance of the particle-containing
filter and the total outer peripheral surface area of the cellulose acetate fiber.
FIG. 7 is a graph showing a relationship between the total outer peripheral surface
area of the cellulose acetate fiber forming a filter plug and the permeability of
typical semivolatile components.
FIG. 8A is a graph showing the permeability of typical semivolatile components of
the filter which is obtained by adding cellulose triacetate particles to a cellulose
acetate fiber having a total outer peripheral surface area of 223 cm2 on average.
FIG. 8B is a graph showing the permeability of typical semivolatile components of
the filter which is obtained by adding cellulose triacetate particles to a cellulose
acetate fiber having a total outer peripheral surface area of 255 cm2 on average.
FIG. 8C is a graph showing the permeability of typical semivolatile components of
the filter which is obtained by adding cellulose particles to a cellulose acetate
fiber having a total outer peripheral surface area of 206 cm2 on average.
FIG. 9A is a schematic view showing a structure of the filter containing filtration
rate control particles used in Example 7.
FIG. 9B is a schematic view showing a structure of the control filter used in Example
7.
FIG. 10 is a graph showing influences of the addition of an additive to the filtration
rate control particles on the permeability of typical semivolatile components of the
filter.
Mode for Carrying Out the Invention
[0011] Hereinafter, several embodiments of the present invention will be described in detail.
[0012] The cigarette filter of the present invention comprises a filter plug which includes
a filter material containing a cellulose acetate fiber tow. Filtration rate control
particles are dispersed in the cellulose acetate fiber tow. The term "dispersed" used
herein generally means that the filtration rate control particles are almost uniformly
distributed over the entire inside of the cellulose acetate fiber tow (refer to FIG.
1), and the distribution may be weighted toward the side of a cigarette mouthpiece
or the side of a cigarette rod. The filtration rate control particles play a role
in controlling to reduce the filter-filtration rate of the semivolatile components
in cigarette mainstream smoke. The filtration rate control particles are selected
from cellulose particles, cellulose triacetate particles, and a mixture thereof.
[0013] Cellulose triacetate particles have an average acetyl substitution degree of 2.76
to 3.00, preferably an average acetyl substitution degree of 2.8 to 3.0, according
to the definition of Japan Chemical Fibers Association. The average acetyl substitution
degree may be measured in accordance with the titration method: ASTM D871-96. The
acetyl substitution degree of the cellulose acetate which is determined by the measuring
method shows a normal distribution. Accordingly, it is defined as the "average acetyl
substitution degree".
[0014] The cellulose acetate fibers may be bound with a plasticizer such as triacetin to
form a tow. The cellulose acetate fibers are extended in parallel to one another over
the total length of the filter.
[0015] The cellulose acetate fibers forming the cellulose acetate fiber tow may be cellulose
acetate fibers to be used for normal cigarette filters. The cellulose acetate fibers
may have a single fineness of 1.5 to 8 deniers and have a sectional shape, such as
a circular shape, an oval shape, a Y-shape, an X-shape or an I-shape. The cellulose
acetate fibers may be formed of cellulose acetate having an acetyl substitution degree
of 2.4 to 2.5 (diacetate). The total fineness of the cellulose acetate fiber tow may
be normally from 15000 to 50000 deniers. The cellulose acetate fiber tow is labeled
as 1.9Y44000. This means that the single fineness is 1.9 deniers, the fiber cross
section has a Y-shape, and the total fineness is 44000 deniers, as well known by those
skilled in the art. In the present specification, the unit of the single fineness
"denier" represents a weight of a piece of fiber per 9000 m (g/9000 m), and the unit
of the total fineness "denier" represents a weight of all pieces of fiber per 9000
m (g/9000 m).
[0016] The cellulose particles hardly adsorb the semivolatile components in cigarette mainstream
smoke and hardly adsorb menthol either (refer to Examples 1 and 2 below). Further,
the cellulose triacetate particles hardly adsorb the semivolatile components in cigarette
mainstream smoke and hardly adsorb menthol either (refer to Examples 1 and 2 below).
As described above, the filtration rate control particles hardly adsorb menthol. Therefore,
in the case where a cigarette filter of the present invention is applied to a menthol
cigarette, there is a low possibility that menthol is significantly adsorbed by the
filter after production of the cigarette up to when it is smoked by a smoker, and
the menthol content in mainstream smoke is hard to be decreased during smoking of
the cigarette.
[0017] The filtration rate control particles have a granular shape. The average sphere equivalent
diameter of the filtration rate control particles is preferably from 100 to 1000 µm,
more preferably greater than 250 µm, from the viewpoints of the hardness and draw
resistance of the filter, the filtration performance, and the easiness of production
of the filter. When producing a filter containing particles having an average sphere
equivalent diameter of 100 to 1000 µm, a normal charcoal filter production machine
may be directly used (in that case, needless to say, the filtration rate control particles
are used in place of charcoal particles). The average sphere equivalent diameter may
be obtained by measuring the particle size distribution using a particle size distribution
measurement device and calculating the 50% median size of the sphere equivalent diameter,
as described in the following examples. The BET specific surface area of the filtration
rate control particles is preferably less than 5 m
2/g. The BET specific surface area may be determined according to a well-known BET
method.
[0018] The filtration rate control particles may be obtained with a compression type granulating
machine. Specifically, they may be obtained with the compression type granulating
machine in the following manner. First, the material of cellulose particles or cellulose
triacetate particles is ground into powder. The resulting ground product and various
additives are mixed with a precision mixer. Thereafter, the resulting mixture is compaction-molded
using a dry granulator while applying a pressure with a roller, and a molded product
(e.g., a plate-shaped product) is obtained. Subsequently, the molded product is crushed
with a dry particle-size selector. At this time, it is roughly crushed at the first
stage, and then it may be crushed into a desired particle size at the second stage.
The resulting crushed product is passed through a sieving machine to screen granules
having a predetermined particle size. As a result, the filtration rate control particles
are prepared. Thus, the filtration rate control particles obtained with the compression
type granulating machine are excellent in terms of high yield and fewer problems due
to the mixing of long fiber during winding of the filter.
[0019] Regarding the filtration rate control particles, the cellulose triacetate particles
may be obtained by grinding cellulose triacetate flakes and classifying them. Alternatively,
the cellulose triacetate particles may be obtained by granulating cellulose triacetate
flakes with a well-known granulating machine such as of a tumbling type, an extrusion
type, a fluid-bed type, a stirring type or a compression type. Further, the cellulose
particles are commercially available.
[0020] Preferably, the filtration rate control particles account for 1.5 to 30% by volume
of the volume of the filter containing the filtration rate control particles. Further,
when considering the production of the filter, if the volume ratio of the added particles
increases, the production tends to be difficult. Thus, in order to satisfy the results
of the filtration rate control and the sensory evaluation without having any effect
of the particles on the production of the filter, the filtration rate control particles
more preferably account for 1.5 to 16% by volume of the volume of the filter containing
the filtration rate control particles (refer to Examples 3 and 4 below). Such ratio
of the filtration rate control particles can achieve a draw resistance of 35 mm H
2O to 180 mm H
2O, which is considered to be suitable for the draw resistance of a filter having a
circumference of 24.5 mm and a length of 25 mm. A volume V of the filter may be determined
by the equation V = πr
2L, where r represents a radius of the filter and L represents a length of the filter
(in this regard, the thickness of the filter wrapping paper is of a level small enough
to be ignored). The addition weight and the apparent density obtained using a mercury
porosimeter were used to calculate the volume of the particles.
[0021] If the filtration rate control particles are added to the cellulose acetate fiber
tow, the hardness of the resulting filter plug increases. Therefore, triacetin as
the plasticizer does not need to be added. Even when triacetin is added as the plasticizer,
the addition amount of triacetin as the plasticizer may be decreased. For example,
when the filtration rate control particles are added to the cellulose acetate fiber
tow at the above ratio, a sufficient hardness of the filter plug is obtained by adding
triacetin in an amount of 3% by weight or less based on the cellulose acetate fiber
tow or not adding (refer to Example 1 below). In this regard, the hardness of the
filter plug may be expressed as the amount of strain of the filter plug when an indenter
having a diameter of 12 mm is pressed against the filter plug under a 300 g loading
for 10 seconds. As the amount of strain is smaller, the filter plug is harder.
[0022] Besides the addition of the filtration rate control particles to the filter, the
addition amount of the plasticizer is decreased or the plasticizer is not added to
the filter. As a result, the permeability of semivolatile components can be further
improved (refer to Example 6 below).
[0023] Further, if the filtration rate control particles are added to the cellulose acetate
fiber tow, the total outer peripheral surface area of the cellulose acetate fiber
can be decreased by 10% or more (usually, 30% or less), as compared to the case where
the filtration rate control particles are not added. As a result, the permeability
of semivolatile components is further improved (refer to Examples 4 and 5 below).
[0024] Further, if a filter obtained by adding the filtration rate control particles to
the cellulose acetate fiber tow is used for the cigarette, the smoking flavor can
be changed as compared with the case where a filter not containing the filtration
rate control particles is used for the cigarette (refer to Example 3 below).
[0025] In order to obtain a more preferable cigarette smoking flavor, a small amount of
an additive may be added to the filtration rate control particles. Example 7 below
demonstrates that even if an additive contributing to cigarette smoking flavor is
added to the filtration rate control particles, no influence is given to the selective
permeation of the semivolatile components. The additive may be a component for smoking
flavor (e.g., a flavorant) or a component having an effect on the smoking flavor (e.g.,
a humectant, amino acid, polysaccharide or dietary fiber). Both the components are
collectively referred to as a "component contributing to smoking flavor". The addition
amount of the component contributing to smoking flavor is preferably 10% by weight
or less, and more preferably 5% by weight or less, based on the total weight of the
particles (the total weight of the filtration rate control particles and the component
contributing to smoking flavor). Examples of the component contributing to smoking
flavor include the following flavorants, humectants, amino acids, polysaccharides,
and dietary fibers.
[0026] The flavorants may be synthetic flavorants, natural flavorants, essential oils, and
the like. Further, they may be used regardless of lipophilicity or hydrophilicity.
Examples of lipophilic flavorants include vanillin, ethyl vanillin, guarlinalool,
thymol, methyl salicylate, linalool, eugenol, menthol, clove, anise, cinnamon, bergamot
oil, geranium, lemon oil, spearmint, and ginger. Examples of hydrophilic flavorants
include glycerin, propylene glycol, ethyl acetate, and isoamyl alcohol.
[0027] Examples of humectants include:
polyols including:
diols [e.g., an alkanediol (e.g., a C2-10 alkanediol such as ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol,
1,4-butanediol, 1,5-pentanediol or hexylene glycol, preferably a C2-8 alkanediol, more preferably a C2-6 alkanediol, particularly a C2-4 alkanediol), and polyalkylene glycol (e.g., diethylene glycol, dipropylene glycol,
triethylene glycol or tripropylene glycol)],
triols [e.g., an alkane triol (e.g., a C3-10 alkane triol such as glycerin or 1,2,6-hexanetriol, preferably a C3-6 alkane triol, more preferably a C3-4 alkane triol)], and
polyols having a tetrafunctional or higher functionality [e.g., a polymer of a polyol
(e.g., alkane triols) having a trifunctional or higher functionality (e.g., polyglycerol
such as diglycerol or triglycerol)]; and
derivatives of these polyols [e.g., dialkylene glycol monoalkyl ether (e.g., methylcarbitol
and ethylcarbitol), and (poly)alkylene glycol monoacylate (e.g., ethylene glycol monoacetate)].
[0028] Examples of amino acids include amino acids and salts thereof (amino acid salts).
The amino acid may be any of a neutral amino acid (monoamino monocarboxylic acid etc.),
an acidic amino acid (monoamino dicarboxylic acid etc.), and a basic amino acid (diaminomonocarboxylic
acid etc.), or may be a sulfur-containing amino acid. The amino acid may be an α-amino
acid, β-amino acid, γ-amino acid, or the like. Particularly, it may be an α-amino
acid. The amino acid may be either an optically active form (D-form, L-form, etc.)
or a racemate. Further, examples of amino acids include polyamino acids having a low
polymerization degree (e.g., a polymerization degree of 2 to 9, preferably a polymerization
degree of 2 to 5, more preferably a polymerization degree of 2 to 3). The amino acid
may have a substituent or may be an amino acid derivative in which at least a part
of the carboxyl group(s) or the amino group(s) is derivatized. For example, at least
a part of the carboxyl group(s) in the amino acid may be a derivatized carboxyl group
(e.g., an amide group).
[0029] Examples of a typical amino acid include:
an aliphatic amino acid [e.g., an aliphatic monoamino carboxylic acid such as glycine,
alanine, isoleucine, leucine, valine, threonine, serine, asparagine, aminosuccinic
acid, cysteine, methionine, glutamine or glutamic acid (e.g., an amino-C2-20-alkane carboxylic acid, preferably an amino-C2-12-alkane carboxylic acid, more preferably an amino-C2-8-alkane carboxylic acid), an aliphatic polyaminocarboxylic acid such as lysine, hydroxylysine,
arginine or cystine (e.g., a polyamino-C2-20-alkane carboxylic acid, preferably a polyamino-C2-12-alkane carboxylic acid)];
an aromatic amino acid (e.g., an aryl-C2-20-alkane carboxylic acid such as phenylalanine or tyrosine, preferably a C6-10-aryl-C2-12-alkane carboxylic acid);
a heterocyclic amino acid (e.g., tryptophan, histidine, proline or 4-hydroxyproline);
and
a polypeptide obtained by the polymerization of these amino acids at a low polymerization
degree (e.g., at a polymerization degree of 9 or less) (e.g., glycyl glycine, glutamyl
glycine, glycyl glycyl glycine, and glycyl proline). Further, examples of amino acid
salts include a metal salt [e.g., an alkali metal salt (e.g., a sodium salt such as
sodium glutamate)], a hydrochloride (e.g., arginine hydrochloride), and a salt of
amino acids (e.g., a salt of lysine with glutamic acid).
[0030] Other examples of components contributing to smoking flavor include food additives
such as xylitol and mannitol; polymers such as lignin; and polysaccharides or dietary
fibers such as cellulose, carboxymethyl cellulose, hydroxypropyl methylcellulose,
chitin, starch, glycogen, guar gum, glucomannan, sodium alginate, agarose, chitosan,
pectin, carrageenan, and xanthan gum.
[0031] Further, a dye may be added to the filtration rate control particles. As the dye,
for example, a natural dye extracted from gardenia, safflower, turmeric, annatto,
red pepper, paprika, red yeast rice, red cabbage, cacao or the like may be added.
The dye may be added in an amount of 0.1 to 5% by weight based on the total weight
of the particles (total weight of the filtration rate control particles and the dye).
Preferably, it may be added in an amount of 1% by weight or less. The filtration rate
control particles containing the dye may have various colors depending on the color
of the dye. When the dye is added to the filtration rate control particles and a transparent
tipping paper is used to produce a filter, the filtration rate control particles (granules)
with which the filter is loaded can be confirmed from the outside. It is known that
human feelings can be influenced by color. Accordingly, it is expected that a new
feeling is provided to the smoking taste of the cigarette by the color of the dye.
Further, when the color of the filtration rate control particles is different from
that of the filter fiber, as with charcoal filter, it is possible to easily distinguish
between the filtration rate control particles and the filter fiber in the quality
inspection in manufacturing the filter.
[0032] The filter of the present invention may be attached to one end of a cigarette rod
singly or in combination with another filter plug. The latter example is shown in
FIG. 1.
[0033] FIG. 1 is a schematic view of a cigarette 10 comprising the filter according to one
embodiment of the present invention. The cigarette 10 comprises a cigarette rod 110
and a filter 120 which is provided at an end in the axial direction of the cigarette
rod 110 in such a manner that the end surface of the filter comes in contact with
the end surface of the cigarette rod. The cigarette rod 110 includes a tobacco filler
112 such as tobacco shreds wrapped in a cigarette paper 111. The filter 120 comprises
a filter plug 121 of the present invention which includes a tow 122 of a lot of cellulose
acetate fibers 123 which are disposed along the axial direction of the filter 120
and may be bundled with a plasticizer such as triacetin. Each of the cellulose acetate
fibers 123 is extended over the total length of the filter plug 121. The filtration
rate control particles 124 are dispersed in the cellulose acetate fiber tow 122. The
filter plug 121 is wrapped in a filter wrapping paper 125. The cigarette rod 110 and
the filter 120 are connected with a tipping paper 130, similarly to a normal filter-tipped
cigarette. A plurality of ventilation holes 131 may be punched in the tipping paper
130 in one or more rows in the circumferential direction of the filter. A so-called
acetate plain filter plug 140 of a cellulose acetate fiber tow 142 wrapped in a filter
wrapping paper 141 may be attached to the posterior end of the filter 120 including
the filtration rate control particles (to the direction of smoke inhalation). In this
case, the filter plug 140 is also wrapped in the tipping paper 130.
Examples
[0034] Hereinafter, the present invention will be described with reference to the examples.
Example 1
<Preparation of filtration rate control particles>
1. Cellulose triacetate particles
[0035] Cellulose triacetate flakes (average acetyl substitution degree: 2.86) were purchased
from Daicel Chemical Industries, Ltd. The acetyl substitution degree of the cellulose
triacetate flakes was measured in accordance with the titration method: ASTM D871-96.
Then, the above-mentioned acetyl substitution degree was confirmed. Subsequently,
the cellulose triacetate flakes were ground with a coffee mill (MK-52M manufactured
by Matsushita Electric Industrial Co., Ltd.). The ground product was classified through
a sieve with an electromagnetic sieve shaker (AS200 control, manufactured by Retsch)
to obtain particles at mesh intervals of 300 to 710 µm. As for the particle size distribution,
the 50% median size of the sphere equivalent diameter was calculated as the average
particle size using a digital-image-analysis type particle size distribution meter
(manufactured by Retsch, (sold at HORIBA, Ltd.)). Regarding the resulting particles,
the average sphere equivalent diameter was 550 µm, the bulk density was 0.54 g/cc,
the apparent density obtained by using a mercury porosimeter was 0.71 g/cc, and the
BET specific surface area obtained by nitrogen desorption method was 4.6 m
2/g.
2. Cellulose particles
[0036] Cellulose particles were cellulose beads obtained by refining and dissolving wood
and forming the resulting viscose into a granular and porous form, and those marketed
under the trademark of Viscopearl in Rengo Co., Ltd. were used. Regarding the used
particles, the average sphere equivalent diameter was 400 µm, the bulk density was
0.20 g/cc, the apparent density obtained by using a mercury porosimeter was 0.34 g/cc,
and the BET specific surface area was below the detection limit.
<Production of filter plug>
[0037] The cellulose particles or cellulose triacetate particles were added to an acetate
filter containing triacetin in the same manner as a generally known method for producing
a charcoal filter. Further, plain acetate filters not containing filtration rate control
particles were also produced. As a filter wrapping paper for each filter plug, one
having a basis weight of 24.0 ± 1.5 g/m
2, a thickness of 60 ± 5 µm, and an air permeability of 10,000 ± 1,800 Coresta unit
was used. The diameter of each of the filter plugs was 7.7 mm and the length was 120
mm. The draw resistance of each of the filters was measured according to ISO6565:
2002.
[0038] The hardness of the resulting filter plugs was measured as the amount of strain of
the filter plug when an indenter having a diameter of 12 mm was pressed against the
filter plug under 300 g loading for 10 seconds.
[0039] The specification and hardness of the resulting filter plugs are shown in Tables
1A to 1C below.
[Table 1A]
Table 1A: Filters containing cellulose triacetate particles |
Filter Nos. |
Specification of cellulose acetate fiber tow |
Amount of triacetin (% by weight) |
Draw resistance per length of 120 mm (mmH2O) |
Addition amount of particles per filter length of 10 mm (mg/10mm) |
Filter hardness (mm) |
A-1 |
3.5Y/35000 |
6 |
418 |
35 |
0.71 |
A-2 |
5.9Y/35000 |
6 |
319 |
35 |
0.54 |
A-3 |
2.2Y/35000 |
6 |
570 |
35 |
0.82 |
A-4 |
3.5Y/35000 |
9 |
396 |
35 |
0.63 |
A-5 |
3.5Y/35000 |
0 |
420 |
35 |
1.2 |
A-6 |
5.9Y/35000 |
6 |
423 |
70 |
0.42 |
[Table 1B]
Table 1B: Filters containing cellulose particles |
Filter Nos. |
Specification of cellulose acetate fiber tow |
Amount of triacetin (% by weight) |
Draw resistance per length of 120 mm (mmH2O) |
Addition amount of particles per filter length of 10 mm (mg/10mm) |
Filter hardness (mm) |
B-1 |
5.9Y/35000 |
6 |
429 |
35 |
0.52 |
B-2 |
5.5Y/31000 |
6 |
337 |
35 |
0.77 |
B-3 |
2.2Y/35000 |
6 |
763 |
35 |
0.77 |
B-4 |
5.9Y/35000 |
9 |
432 |
35 |
0.48 |
B-5 |
5.9Y/35000 |
0 |
439 |
35 |
0.97 |
B-6 |
2.5Y/35000 |
6 |
430 |
10 |
0.97 |
[Table 1C]
Table 1C: Acetate plain filters |
Filter Nos. |
Specification of cellulose acetate fiber tow |
Amount of triacetin (% by weight) |
Draw resistance per length of 120 mm (mmH2O) |
Addition amount of particles per filter length of 10 mm (mg/10mm) |
Filter hardness (mm) |
AF-1 |
2.2Y/35000 |
0 |
470 |
- |
1.6 |
AF-2 |
5.9Y/35000 |
0 |
197 |
- |
1.6 |
AF-3 |
2.2Y/35000 |
6 |
433 |
- |
1.0 |
AF-4 |
5.5Y/31000 |
6 |
169 |
- |
1.1 |
[0040] The hardness of the filters (A-1 to A-6) containing cellulose triacetate particles
was from 0.42 to 1.2 (mm). The hardness of the filters (B-1 to B-6) containing cellulose
particles was from 0.48 to 0.97 (mm). On the other hand, in the acetate plain filters,
the hardness of the acetate plain filters (AF-1 and AF-2) not containing triacetin
was 1.6 (mm). Therefore, it was found that the hardness of the filters is increased
by the inclusion of the particles in the filters containing cellulose particles and
the filters containing cellulose triacetate particles. When the addition amount of
the particles is increased, the hardness of the filters can be guaranteed regardless
of the addition of triacetin.
<Production of cigarette sample>
[0041] The filter of the commercially available filter-tipped cigarette "Mild Seven Aqua
Squash Menthol" was removed. The resultant cigarette rod was connected to a filter
for evaluation obtained by cutting the above-produced filter plug into various lengths
and placing it in a paper tube (outer diameter: 7.7 mm) with an adhesive tape to produce
a cigarette sample. The length and draw resistance of each of the cut filters are
shown in Tables 2A to 2C below. It took a month to perform the smoking test after
the production of the filters.
[Table 2A]
Table 2A: Cut filters containing cellulose triacetate particles |
Filter plug Nos. (before cutting) |
Filter length after cutting (mm) |
Draw resistance (mmH2O) |
Marks of cigarettes comprising cut filters |
A-1 |
20 |
72 |
CA-1 |
A-2 |
20 |
53 |
CA-2 |
A-3 |
20 |
93 |
CA-3 |
A-4 |
20 |
69 |
CA-4 |
A-5 |
20 |
71 |
CA-5 |
A-6 |
20 |
70 |
CA-6 |
[Table 2B]
Table 2B: Cut filters containing cellulose particles |
Filter plug Nos. (before cutting) |
Filter length after cutting (mm) |
Draw resistance (mmH2O) |
Marks of cigarettes comprising cut filters |
B-1 |
20 |
72 |
CB-1 |
B-2 |
20 |
56 |
CB-2 |
B-3 |
20 |
129 |
CB-3 |
B-4 |
20 |
73 |
CB-4 |
B-5 |
20 |
75 |
CB-5 |
B-6 |
20 |
71 |
CB-6 |
[Table 2C]
Table 2C: Cut filters containing acetate plain filters |
Filter plug Nos. (before cutting) |
Filter length after cutting (mm) |
Draw resistance (mmH2O) |
Marks of cigarettes comprising cut filters |
AF-3 |
10 |
38 |
CAF-3-1 |
AF-3 |
15 |
55 |
CAF-3-2 |
AF-3 |
20 |
69 |
CAF-3-3 |
AF-3 |
30 |
104 |
CAF-3-4 |
AF-3 |
40 |
133 |
CAF-3-5 |
AF-4 |
10 |
14 |
CAF-4-1 |
AF-4 |
15 |
22 |
CAF-4-2 |
AF-4 |
20 |
28 |
CAF-4-3 |
AF-4 |
30 |
38 |
CAF-4-4 |
AF-4 |
40 |
55 |
CAF-4-5 |
<Smoking test>
[0042] Ten cigarette samples produced in the above process (ventilation holes were closed
with an adhesive tape) were automatically smoked using an automatic smoking machine
(RM20D, manufactured by Borgwaldt KC Inc.) under the following conditions: puff volume:
35.0 mL/2 sec, puff duration: 2 sec/puff, puff interval: 1 puff/min. The particulate
matter in cigarette smoke was collected with a Cambridge filter (CM-133, manufactured
by Borgwaldt KC Inc.). The smoke passed through the Cambridge filter was collected
on 10 mL of methanol cooled to 70°C with a coolant of dry ice and isopropanol.
[0043] The Cambridge filter having the particulate matter collected, 10 mL of a methanol
solution containing the cigarette smoke collected, and 1 mL of an internal standard
solution (d-32 pentadecane: 0.05 mg/mL, d-1-ethanol: 150 mL/L, anethole: 2 mL/L, 1,3-butanediol:
4 mL/L) were added to a serum bottle, which was shaken for 30 minutes. After shaking,
the supernatant liquid was collected and used as a sample for analysis. The above
operation was also performed on the cigarette rod (control cigarette) obtained by
removing the filter of the commercially available filter-tipped cigarette "Mild Seven
Aqua Squash Menthol".
<Analysis of tar, nicotine, and semivolatile components>
[0044] The sample for analysis was analyzed by gas chromatography-mass spectrometry (GC-MSD).
Agilent 7890A (Agilent Technologies Inc.) was used for GC, and Agilent 5975C (Agilent
Technologies Inc.) was used for MSD.
[0045] The peak area of each component (standardized by the internal standard) in the chromatogram
obtained by the analysis was compared to the peak area of each component in the chromatogram
regarding the control cigarette. The permeability "1-E
x" of each smoke component through each filter was calculated using the following formula.
[0046] In the above formula, "A
x, in" and "A
x, out" represent values obtained by standardizing the peak areas of a component "x" in
smoke of the control cigarette and each of the filter-tipped cigarette sample, respectively,
by the internal standard. "Ex" represents a filtration rate of the component "x".
[0047] As for the semivolatile components, 3-furaldehyde, 2-acetylfuran, and furfural were
selected as typical semivolatile components. The average permeability of the components
was calculated, and the selective filtration performance of the semivolatile components
was evaluated.
[0048] Regarding the cigarettes CAF-3-1 to CAF-3-5 and CAF-4-1 to CAF-4-5, the draw resistance
of each filter is represented on the horizontal axis, and the logarithm values of
the permeability of tar, nicotine, and the typical semivolatile components are plotted
on the vertical axis. These are shown in FIG. 2. FIG. 2(A) shows the permeability
of tar, FIG. 2(B) shows the permeability of nicotine, and FIG. 2(C) shows the permeability
of the typical semivolatile components. In FIGS. 2(A) to 2(C), the circles relate
to CAF-3-1 to CAF-3-5, and the triangles relate to CAF-4-1 to CAF-4-5.
[0049] Regarding the tar (FIG. 2(A)) and the nicotine (FIG. 2(B)), the permeability can
be linearly approximated regardless of the kind of the cellulose acetate tow fiber.
Regarding the typical semivolatile components (FIG. 2(C)), the permeability has a
different slope depending on the kind of the tow fiber (the diameter of the fiber).
This shows that the permeability of tar and nicotine is regulated by only the draw
resistance of each filter; however, the permeability behavior of the typical semivolatile
components varies depending on the kind of the tow. Since the tar and nicotine are
basically particulate phase components, the filtration efficiency may be represented
as a function of the draw resistance of each filter. On the other hand, the semivolatile
components are distributed to both the vapor phase and the particulate phase, and
thus the permeability behavior is influenced by filtration of the particulate phase
component and absorption of the vapor phase component to the fiber. As a result, it
is not regulated by only the draw resistance.
[0050] Subsequently, the results of the cigarettes CA-1 to CA-5 and CB-1 to CB-5 are shown
in FIG. 3. FIG. 3(A) shows the permeability of tar, FIG. 3(B) shows the permeability
of nicotine, and FIG. 3(C) shows the permeability of the typical semivolatile components.
In FIGS. 3(A) and 3(B), a line 'a' relates to CAF-3-1 to CAF-3-3 and CAF-4-4 to CAF-4-5,
a line 'b' relates to the cigarettes CA-1 to CA-5, and a line 'c' relates to the cigarettes
CB-1 to CB-5. In FIG. 3(C), a line 'a' relates to CAF-3-1 to CAF-3-5 and a line 'b'
relates to CAF-4-1 to CAF-4-5.
[0051] The results shown in FIGS. 3(A) and 3(B) show that the filter containing the filtration
rate control particles of the present invention has a high permeability of tar and
nicotine as compared to that of the acetate plain filter, in other words, it has a
low filtration rate of tar and nicotine. From the results shown in FIG. 3(C), it is
found that the filter containing the filtration rate control particles of the present
invention has a high permeability of the semivolatile components as compared to the
acetate plain filter. That is, the filtration rate control particles of the present
invention allow the permeation of the semivolatile components to be significantly
improved. On the other hand, the present inventors have demonstrated that the filter
containing the cellulose diacetate particles (average acetyl substitution degree:
2.4 to 2.5) has a function in filtrating the semivolatile components and hardly allows
the semivolatile components to be permeated as compared to the acetate plain filter.
[0052] From the results shown in FIG. 3(A), the filter containing the filtration rate control
particles of the present invention has a different filtration rate of tar from that
of the acetate plain filter. In order to reveal the filtering characteristics of the
semivolatile components in comparison with tar, the selective filtration coefficient
S
x was calculated by the following formula as an indicator showing the component selectivity
in filtration of the typical semivolatile components.
[0053] In the above formula, E
TPM represents the filtration rate of crude tar (the total particulate matter).
[0054] The selective filtration coefficient S
x thus calculated was plotted against the filter draw resistance. The results are shown
in FIG. 4. In FIG. 4, a line 'a' relates to the cigarettes CAF-4-1 to CAF-4-5, and
a line 'b' relates to CAF-3-1 to CAF-3-5. The results shown in FIG. 4 show the following.
When comparing the filters having the same single fineness, the selective filtration
coefficient of the filter containing the filtration rate control particles of the
present invention is decreased as compared to that of the acetate plain filter in
any case of filter draw resistance. Even if the filtration rate of tar is taken into
consideration, the semivolatile components are permeated selectively.
[0055] Subsequently, in order to examine the effect of the plasticizer (triacetin (GTA))
added to the filter material on the permeability of the typical semivolatile components,
as for the cigarette CA-1 (triacetin: 6% by weight), the cigarette CA-4 (triacetin:
9% by weight), the cigarette CA-5 (triacetin: 0%), the cigarette CB-1 (triacetin:
6% by weight), the cigarette CB-4 (triacetin: 9% by weight), and the cigarette CB-5
(triacetin: 0%), the selective filtration coefficient S
x of the typical semivolatile components was plotted against the draw resistance. The
results are shown in FIG. 5. As shown in FIG. 5, if the addition amount of triacetin
is small, it acts in the direction where the semivolatile components are permeated.
If the addition amount of triacetin is large, it acts in the direction where the semivolatile
components are filtrated. The permeability of the typical semivolatile components
can also be controlled by the amount of triacetin. This is because the vapor of the
semivolatile components is absorbed (adsorbed) into triacetin on the surface of the
cellulose acetate fiber. It is considered that if the addition amount of triacetin
is decreased, the adsorption amount of the semivolatile components decreases. In the
filter containing the filtration rate control particles of the present invention,
even if the addition amount of triacetin is decreased, the filter hardness can be
guaranteed. Therefore, a filter which allows the semivolatile components to be more
selectively permeated can be achieved by decreasing the addition amount of triacetin.
[0056] When the above results are summarized, it was found that the filter containing the
filtration rate control particles of the present invention is effective in the selective
permeation of the semivolatile components in view of the design of the filter and
the easiness in production, although the selective permeation of the semivolatile
components can also be controlled by the diameter of cellulose acetate fibers forming
a tow and the amount of triacetin.
Example 2
[0057] When the filter of the present invention is intended to be used for a menthol tobacco
product, if the adsorption of menthol to the filtration rate control particles of
the present invention is continued, the amount of menthol in mainstream smoke is decreased.
Therefore, the adsorption amount of menthol to the filtration rate control particles
of the present invention was examined.
[0058] Specifically, an acetate plain filter (cellulose acetate fiber tow: 1.9Y44000, weight:
30 mg, filter length: 5 mm) was attached to an end of a cigarette rod (circumference:
24.9 mm, length: 59 mm) having 640 mg of tobacco shreds containing 0.59% by weight
of menthol. A mentholated acetate filter (cellulose acetate fiber tow: 2.5Y35000,
weight: 90 mg, filter length: 15 mm) in which a menthol-containing string was threaded
through the center of the filter was arranged at a distance of 5 mm from the acetate
plain filter. The cavity between both the filters was filled with the filtration rate
control particles of the present invention (cellulose particles or cellulose triacetate
particles prepared in Example 1). The content of menthol in the mentholated acetate
filter was 1.99% by weight. A cigarette whose cavity is filled with cellulose particles
as the filtration rate control particles is designated as a cigarette A, while a cigarette
whose cavity is filled with cellulose triacetate particles as the filtration rate
control particles is designated as a cigarette B.
[0059] The cigarettes thus produced were placed in a glass bottle and sealed, followed by
storage at 50°C for two weeks. The cigarette samples after the storage were taken
out from the glass bottle. Then, the content of menthol in each of tobacco shreds,
acetate plain filters, filtration rate control particles, and mentholated acetate
filters was quantified. The content of menthol was quantified by performing methanol-extraction
of the samples to be measured (tobacco shreds, acetate plain filters, filtration rate
control particles or mentholated acetate filters) and analyzing the methanol-extract
with a gas chromatograph (6890 series, manufactured by HEWLETT PACKARD). In the preliminary
test, it was confirmed that menthol was extracted with methanol.
[0060] The content of menthol in each of tobacco shreds, acetate plain filters, filtration
rate control particles, and mentholated acetate filters is shown in Table 3 below.
[Table 3]
Table 3: Content of menthol (unit: % by weight) |
|
Tobacco shreds |
Acetate plain filter |
Filtration rate control particles |
Mentholated acetate filters |
Before storage |
0.59 |
0 |
0 |
1.99 |
After storage |
Cigarette A |
0.56 |
2.03 |
Cellulose particles 0.20 |
1.97 |
Cigarette B |
0.43 |
2.30 |
Cellulose acetate particles 0.22 |
2.23 |
[0061] From the results shown in Table 3, it is found that the filtration rate control particles
of the present invention (cellulose particles and cellulose triacetate particles)
hardly adsorb menthol. Therefore, even if the filter of the present invention containing
the filtration rate control particles is used for a menthol tobacco product, the undesired
adsorption of menthol to the filtration rate control particles is hardly caused, and
thus the menthol smoking taste can be sufficiently experienced.
Example 3
[0062] Filter-tipped cigarettes having the structure shown in FIG. 1 were produced. The
tipping paper having ventilation holes punched and a filter were removed from the
commercially available filter-tipped cigarette "Mild Seven Aqua Squash Menthol 7 Box",
and the obtained cigarette rod was used as the cigarette rod 110 (content of menthol
in tobacco shreds: 0.55% by weight). Each of the filters A-1 and A-6 shown in Table
1A, the filters B-1 and B-6 shown in Table 1B, and the filter AF-3 shown in Table
1C was cut into a length of 10 mm so that the filter draw resistance is 35 ± 2 mm
H
2O so as to almost constantly keep the amounts of tar, nicotine, and menthol in cigarette
mainstream smoke, and the obtained filter plugs were used as the filter plug 121.
The acetate plain filter 140 (cellulose acetate fiber tow: 5.0Y35000 (containing 6.9%
by weight of triacetin); filter length: 17 mm, menthol content: 2.22% by weight) was
attached to the rear end of the filter plug 121. The filter plugs 121 and 140 were
connected to the cigarette rod using the tipping paper. It took three months to perform
the smoking test after the production of the filters. For confirmation, the specification
of the filter plug 121 is shown in Table 4 below.
[Table 4]
Table 4: Cut filters |
Filter plug Nos. (before cutting) |
Filter length after cutting (mm) |
Draw resistance (mmH2O) |
Marks of cigarettes comprising cut filters |
A-1 |
10 |
35±2 |
CA-1-2 |
A-6 |
10 |
35±2 |
CA-6-2 |
B-1 |
10 |
35±2 |
CB-1-2 |
B-6 |
10 |
35±2 |
CB-6-2 |
AF-3 |
10 |
35±2 |
CAF-3-1-2 |
[0063] Among the cigarettes comprising the filters shown in Table 4, five each of the cigarettes
(CA-6-2 and CB-1-2) containing a large amount of the filtration rate control particles
in the filters thereof and five of the control cigarette (CAF-3-1-2) were smoked without
closing the ventilation holes under the smoking conditions described in Example 1.
The amounts of tar, nicotine, and menthol in mainstream smoke were measured and the
puff number was also measured. The measurement results (averages) of the amounts of
tar, nicotine, and menthol per cigarette as well as the puff number are shown in Table
5 below.
[Table 5]
Table 5: Amounts of tar, nicotine and menthol in mainstream smoke per cigarette, as
well as puff number |
Cigarette |
Tar (mg) |
Nicotine (mg) |
Menthol (mg) |
Puff number |
CAF-3-1-2 |
7.9 |
0.55 |
0.40 |
6.9 |
CB-1-2 |
8.8 |
0.62 |
0.45 |
6.9 |
CA-6-2 |
8.9 |
0.64 |
0.45 |
6.9 |
[0064] Subsequently, nine evaluation panelists evaluated the smoking taste of the cigarettes.
The evaluation panelists felt the difference in smoking taste between the cigarettes
CB-1-2 and CB-6-2 and the control cigarette CAF-3-1-2. As for the characteristics
of the smoking flavor of the cigarettes CB-1-2 and CB-6-2, they detected menthol strongly
and clearly.
[0065] They also felt the difference in smoking taste between the cigarettes CA-1-2 and
CA-6-2 and the control cigarette CAF-3-1-2. As for the characteristics of the smoking
flavor of the cigarettes CA-1-2 and CA-6-2, they detected menthol strongly and clearly.
Further, as for the smoking flavor of the cigarettes CA-1-2 and CA-6-2, they sharply
detected the smoking flavor, hardly detected a left bitter taste, and detected a strong
tobacco-like flavor. After smoking, they lost the taste immediately and hardly had
a strong aftertaste.
Example 4
<Total outer peripheral surface area of cellulose acetate>
[0067]
- (1) The circle equivalent diameter of the single fiber is calculated from the following
equation.
In the above equation, the fiber density is 1.32 g/cm3.
- (2) Subsequently, the shape coefficient of the cross section of the single fiber is
calculated from the following equation.
In the above equation, the actual fiber outer peripheral length and the actual cross-sectional
area are actually measured from a photomicrograph of the cross section of the single
fiber.
- (3) Subsequently, the outer peripheral length of the single fiber is calculated from
the following equation.
- (4) Finally, the total outer peripheral surface area is determined from the following
equation.
[0068] In the above equation, the fiber length is calculated by removing the amount of triacetin
from the actually measured weight of the acetate tow to obtain a net weight of the
acetate tow and dividing the net weight of the acetate tow by a weight obtained by
converting the total fineness into a weight per filter length.
Table 6: Specification of filters |
Filtration rate control particles |
Particle size (µm) |
Addition amount of particles per length of 10 cm (mg/10cm) |
Specification of cellulose acetate fiber tow |
Total outer peripheral surface area of cellulose acetate fiber per filter length of
10 cm (cm2/10cm) |
Addition amount of triacetin (% by weight) |
Filter length (mm) |
Fiber length (mm) |
Draw resistance (mmH2O) |
percentage of particles to volume of filters (% by volume) |
Cellulose particle |
400 |
35 |
5.5Y31000 |
80 |
6 |
10 |
11.5 |
28 |
22.3 |
400 |
35 |
5.9Y35000 |
87 |
6 |
10 |
11.8 |
36 |
22.3 |
400 |
35 |
2.2Y35000 |
123 |
6 |
10 |
11.4 |
65 |
22.3 |
400 |
35 |
5.9Y35000 |
87 |
0 |
10 |
12.2 |
38 |
22.3 |
400 |
25 |
5.9Y35000 |
87 |
6 |
10 |
11.9 |
28 |
15.9 |
400 |
25 |
5.9Y35000 |
87 |
0 |
10 |
12.0 |
28 |
15.9 |
400 |
25 |
5.9Y35000 |
87 |
3 |
10 |
11.9 |
28 |
15.9 |
700 |
25 |
5.9Y35000 |
87 |
6 |
10 |
12.1 |
27 |
15.9 |
Cellulose acetate particle |
400 |
35 |
5.9Y35000 |
87 |
6 |
10 |
12.8 |
27 |
10.7 |
400 |
35 |
3.5Y35000 |
108 |
6 |
10 |
12.2 |
36 |
10.7 |
400 |
35 |
2.2Y35000 |
124 |
6 |
10 |
11.6 |
46 |
10.7 |
400 |
70 |
5.9Y35000 |
87 |
6 |
10 |
12.3 |
35 |
21.3 |
400 |
35 |
3.5Y35000 |
108 |
0 |
10 |
12.3 |
35 |
10.7 |
400 |
35 |
5.0Y35000 |
92 |
6 |
10 |
12.1 |
26 |
10.7 |
400 |
35 |
5.0Y35000 |
92 |
0 |
10 |
12.1 |
26 |
10.7 |
400 |
35 |
5.0Y35000 |
92 |
3 |
10 |
12.0 |
26 |
10.7 |
[0069] The results are shown in Table 6.
[0070] Regarding the results shown in Table 6, the draw resistance of each filter is plotted
against the total outer peripheral surface area of each cellulose acetate fiber, and
the results are shown in FIG. 6. In FIG. 6, the black rhombuses relate to acetate
plain filter plugs, the white triangles relate to filter plugs containing cellulose
particles, and the white squares relate to filter plugs containing cellulose triacetate
particles. FIG. 6 shows that, in any case of the draw resistance, the filter plugs
containing the filtration rate control particles of the present invention have a smaller
total outer peripheral surface area of the cellulose acetate fiber as compared to
that of the acetate plain filter plugs. In the filter plugs containing the filtration
rate control particles of the present invention, a reduction rate of the total outer
peripheral surface area of the cellulose acetate fiber is about from 10 to 30%. Therefore,
in the case where the filtration rate control particles of the present invention are
added, a cellulose acetate fiber tow having a smaller total outer peripheral surface
area can be used as compared to the case where the particles are not added, in producing
filter plugs having the same draw resistance.
Example 5
[0071] Regarding the cigarettes CA-1 to CA-6, CB-1 to CB-6, CAF-3-1 to CAF-3-5 and CAF-4-1
to CAF4-5 (refer to Tables 2A to 2C), and the cigarettes comprising the filter plugs
shown in Tables 7A and 7B below, the total outer peripheral surface area of the cellulose
acetate fiber and the permeability and selective permeation coefficient of the typical
semivolatile components were calculated. The results are shown in Tables 8A and 8B
below.
[Table 7A]
Table 7A: Filters containing cellulose particles (average particle size: 700 µm) |
Filter Nos. |
Specification of cellulose acetate fiber tow |
Amount of triacetin (% by weight) |
Filter length (mm) |
Draw resistance (mmH2O) |
Addition amount of particles per filter length of 10 mm (mg/10mm) |
Marks of cigarettes comprising corresponding filters |
B2-1 |
5.9Y/35000 |
6 |
20 |
72 |
35 |
CB2-1 |
B2-2 |
2.2Y/35000 |
6 |
20 |
117 |
35 |
CB2-2 |
B2-3 |
5.9Y/35000 |
9 |
20 |
71 |
35 |
CB2-3 |
B2-4 |
5.9Y/35000 |
0 |
20 |
74 |
35 |
CB2-4 |
B2-5 |
2.5Y/35000 |
6 |
20 |
70 |
10 |
CB2-5 |
[Table 7B]
Table 7B: Acetate plain filters |
Filter plug Nos. (before cutting) |
Filter length after cutting (mm) |
Draw resistance (mmH2O) |
Marks of cigarettes comprising cut filters |
AF-1 |
10 |
40 |
CAF-1-1 |
AF-1 |
15 |
58 |
CAF-1-2 |
AF-1 |
20 |
76 |
CAF-1-3 |
AF-1 |
30 |
112 |
CAF-1-4 |
AF-1 |
40 |
146 |
CAF-1-5 |
AF-2 |
10 |
18 |
CAF-2-1 |
AF-2 |
15 |
26 |
CAF-2-2 |
AF-2 |
20 |
35 |
CAF-2-3 |
AF-2 |
30 |
53 |
CAF-2-4 |
AF-2 |
40 |
68 |
CAF-2-5 |
[Table 8A]
Table 8A |
Cigarette |
Total outer peripheral surface area of cellulose acetate fiber (cm2) |
Permeability of typical semivolatile components |
Selective permeation coefficient of typical semivolatile components |
CA-1 |
214 |
0.17 |
3.78 |
CA-2 |
174 |
0.17 |
4.57 |
CA-3 |
247 |
0.10 |
5.60 |
CA-4 |
214 |
0.09 |
7.30 |
CA-5 |
214 |
0.28 |
2.38 |
CA-6 |
174 |
0.15 |
4.43 |
CB-1 |
174 |
0.21 |
3.42 |
CB-2 |
160 |
0.16 |
4.84 |
CB-3 |
247 |
0.08 |
6.87 |
CB-4 |
174 |
0.09 |
7.32 |
CB-5 |
174 |
0.47 |
1.51 |
CB-6 |
245 |
0.13 |
4.64 |
CB2-1 |
174 |
0.18 |
3.84 |
CB2-2 |
247 |
0.13 |
4.08 |
CB2-3 |
174 |
0.15 |
4.69 |
CB2-4 |
174 |
0.45 |
1.56 |
CB2-5 |
245 |
0.17 |
3.63 |
[Table 8B]
Table 8B |
Cigarette |
Total outer peripheral surface area of cellulose acetate fiber (cm2) |
Permeability of typical semivolatile components |
Selective permeation coefficient of typical semivolatile components |
CAF-3-1 |
124 |
0.35 |
2.25 |
CAF-3-2 |
186 |
0.20 |
3.34 |
CAF-3-3 |
247 |
0.15 |
3.56 |
CAF-3-4 |
371 |
0.04 |
11.39 |
CAF-3-5 |
495 |
0.03 |
12.03 |
CAF-4-1 |
80 |
0.51 |
1.80 |
CAF-4-2 |
120 |
0.37 |
2.32 |
CAF-4-3 |
160 |
0.23 |
3.44 |
CAF-4-4 |
240 |
0.11 |
6.06 |
CAF-4-5 |
320 |
0.06 |
9.69 |
CAF-1-1 |
124 |
0.58 |
1.34 |
CAF-1-2 |
186 |
0.40 |
1.76 |
CAF-1-3 |
247 |
0.30 |
2.05 |
CAF-1-4 |
371 |
0.19 |
2.49 |
CAF-1-5 |
495 |
0.09 |
3.77 |
CAF-2-1 |
87 |
0.68 |
1.29 |
CAF-2-2 |
131 |
0.61 |
1.40 |
CAF-2-3 |
174 |
0.54 |
1.49 |
CAF-2-4 |
262 |
0.37 |
1.88 |
CAF-2-5 |
349 |
0.25 |
2.28 |
[0072] Regarding the results shown in Tables 8A and 8B, the permeability of the typical
semivolatile components is plotted against the total outer peripheral surface area
of the cellulose acetate fiber, and the results are shown in FIG. 7. In FIG. 7, the
white triangles relate to the cigarettes CB-5 and CB2-4, the white squares relate
to the cigarette CA-5, the white circles relate to the cigarettes CAF-1-1 to CAF-1-5,
and the white rhombuses relate to the cigarettes CAF-2-1 to CAF-2-5. The plasticizer
is not contained in the filter plugs of any of the above-mentioned cigarettes. In
FIG. 7, the black triangles relate to the cigarettes CB-1, CB-2, CB-3, CB-6, CB2-1,
CB2-2, and CB2-5, the black squares relate to the cigarettes CA-1, CA-2, CA-3, and
CA-6, the black circles relate to the cigarettes CAF-3-1 to CAF-3-5, and the black
rhombuses relate to the cigarettes CAF-4-1 to CAF-4-5. The plasticizer is contained
in the filter plugs of all the above-mentioned cigarettes.
[0073] From FIG. 7, it is found that the permeability of the typical semivolatile components
in each of the acetate plain filter plugs is largely dependent on the addition amount
of the plasticizer (triacetin); however, in the case of the same amount of the plasticizer,
the permeability of the typical semivolatile components is determined by the total
outer peripheral surface area of the cellulose acetate fiber. Further, it is found
that the particle size of cellulose particles has no influence on the filtering characteristics
of the semivolatile components. These facts are attributed to the fact that cellulose
particles and cellulose triacetate particles are not easily dissolved in an acetone
solvent and hardly adsorb menthol or triacetin, and thus they have a low adsorbing
ability for semivolatile components having a polarity close to that of menthol or
triacetin.
[0074] FIG. 7 shows that the selective filtering characteristics of the semivolatile components
can be controlled by changing the kind of the cellulose acetate fiber tow or the addition
amount of the plasticizer. However, since a certain level of hardness of the filter
needs to be guaranteed and the draw resistance needs to be controlled when setting
the amounts of tar and nicotine in mainstream smoke, it is not possible to freely
combine the kind of the cellulose acetate fiber tow and the addition amount of the
plasticizer for cigarette products. However, if the filtration rate control particles
(cellulose particles and/or cellulose triacetate particles) are added to a filter
according to the present invention, the constant hardness of the filter can be maintained
by the presence of the particles even if the addition amount of triacetin is decreased,
and the draw resistance can be controlled by the addition of the particles in order
to adjust the amount of tar/nicotine in mainstream smoke to a desired value. Therefore,
the cellulose acetate fiber tow regarded as unusable in the prior art (i.e., a cellulose
acetate fiber tow whose total outer peripheral surface area is small) can be used
according to the present invention. In other words, generally, as the total outer
peripheral surface area of the cellulose acetate fiber becomes smaller, the draw resistance
of the filter plug tends to decrease. Thus, a cellulose acetate fiber tow having the
draw resistance lower than that of the cellulose acetate fiber tow of the conventional
cigarette filter can be used. As a result, it is possible to develop a filter having
characteristics in which the semivolatile components are permeated selectively as
compared to tar.
[0075] As described above, it is found that, if the filtration rate control particles (cellulose
particles and/or cellulose triacetate particles) are added to a filter according to
the present invention, the control width of the permeation of the semivolatile components
can be extended, which has been limited in the conventional acetate plain filter in
view of product design or production. Thus, the present invention is effective in
providing new tobacco smoking flavor or new menthol tobacco smoking flavor.
Example 6
[0076] The cellulose powder (FMC Biopolymer, trade name: Endurance MCC) and the cellulose
triacetate powder (Daicel Chemical Industries, Ltd., trade name: Acetate Flake DS2.9
LT-55 (TAC)) were used as raw materials. Each powder was pressurized at 20 Mpa for
10 minutes using a tablet molding machine (manufactured by Jasco Corporation) and
a hydraulic hand pump (manufactured by Riken Seiki Co., Ltd.) to obtain a plate-shaped
molded product. Subsequently, the resulting plate-shaped molded product was ground
with a coffee mill (MK-52M manufactured by Matsushita Electric Industrial Co., Ltd.).
The ground product was classified through a sieve with an electromagnetic sieve shaker
(AS200 control, manufactured by Retsch) to produce filtration rate control particles
at mesh intervals of 300 to 710 µm. The resulting filtration rate control particles
were used to produce filters containing cellulose triacetate particles and filters
containing cellulose particles according to the same procedure as Example 1. The draw
resistance and hardness of the produced filters were measured according to the same
procedure as Example 1.
[0077] The specification and hardness of the resulting filter plugs are shown in Tables
9A and 9B below.
[Table 9A]
Table 9A: Filters containing cellulose triacetate particles |
Filter Nos. |
Specification of cellulose acetate fiber tow |
Addition amount of triacetin (% by weight) |
Draw resistance per length of 120 mm (mmH2O) |
Addition amount of particles per filter length of 10 mm (mg/10mm) |
Filter hardness (mm) |
A-7 |
5.0Y35000 |
6 |
311 |
35 |
0.54 |
A-8 |
5.0Y35000 |
3 |
307 |
35 |
0.70 |
A-9 |
5.0Y35000 |
0 |
314 |
35 |
1.2 |
A-10 |
3.5Y35000 |
6 |
327 |
29 |
0.75 |
A-11 |
3.5Y35000 |
3 |
332 |
29 |
1.0 |
A-12 |
3.5Y35000 |
1 |
322 |
29 |
1.3 |
[Table 9B]
Table 9B: Filters containing cellulose particles |
Filter Nos. |
Specification of cellulose acetate fiber tow |
Addition amount of triacetin (% by weight) |
Draw resistance per length of 120 mm (mmH2O) |
Addition amount of particles per filter length of 10 mm (mg/10mm) |
Filter hardness (mm) |
B-7 |
5.9Y35000 |
6 |
339 |
25 |
0.52 |
B-8 |
5.9Y35000 |
3 |
334 |
25 |
0.7 |
B-9 |
5.9Y35000 |
0 |
331 |
25 |
1.0 |
B-10 |
5.0Y35000 |
6 |
343 |
21 |
0.65 |
B-11 |
5.0Y35000 |
1 |
321 |
21 |
1.1 |
[0078] In Tables 9A and 9B, the addition amount of triacetin is expressed in percent by
weight based on the cellulose acetate fiber tow.
[0079] The hardness of the filters (A-7 to A-12) containing cellulose triacetate particles
was from 0.54 to 1.3 (mm). The hardness of the filters (B-7 to B-12) containing cellulose
particles was from 0.52 to 1.1 (mm). On the other hand, in the acetate plain filters,
the hardness of the acetate plain filters (AF-1 and AF-2) not containing triacetin
was 1.6 (mm). Therefore, it was found that the hardness of the filters is increased
by the inclusion of the particles in the filters containing cellulose particles and
the filters containing cellulose triacetate particles. When the addition amount of
the particles is increased, the hardness of the filters can be guaranteed even if
the addition amount of triacetin is decreased. Specifically, it was found that when
3% by weight or less of triacetin was added or even when triacetin was not added,
the sufficient hardness of the filter plugs was obtained.
<Production of cigarette samples>
[0080] The filter of commercially available filter-tipped cigarette "Seven Stars Solid Menthol"
was removed. The resultant cigarette rod was connected to a filter for evaluation
obtained by cutting the above-produced filter plug into various lengths and placing
it in a paper tube (outer diameter: 7.7 mm) with an adhesive tape to produce a cigarette
sample. It took two months to perform the smoking test after the production of the
filters. The length and draw resistance of each of the cut filters as well as the
total outer peripheral surface area of the cellulose acetate fiber are shown in Tables
10A and 10B below.
[Table 10A]
Table 10A: Cut filters containing cellulose triacetate particles |
Filter plug Nos. (before cutting) |
Filter length after cutting (mm) |
Draw resistance (mmH2O) |
Total outer peripheral surface area of cellulose acetate fiber (cm2) |
Marks of cigarettes comprising cut filters |
A-7 |
20 |
54 |
223 |
CA-7 |
A-8 |
20 |
53 |
222 |
CA-8 |
A-9 |
20 |
54 |
224 |
CA-9 |
A-10 |
20 |
53 |
255 |
CA-10 |
A-11 |
20 |
54 |
256 |
CA-11 |
A-12 |
20 |
56 |
255 |
CA-12 |
[Table 10B]
Table 10B: Cut filters containing cellulose particles |
Filter plug Nos. (before cutting) |
Filter length after cutting (mm) |
Draw resistance (mmH2O) |
Total outer peripheral surface area of cellulose acetate fiber (cm2) |
Marks of cigarettes comprising cut filters |
B-7 |
20 |
56 |
202 |
CB-7 |
B-8 |
20 |
57 |
202 |
CB-8 |
B-9 |
20 |
59 |
204 |
CB-9 |
B-10 |
20 |
62 |
207 |
CB-10 |
B-11 |
20 |
58 |
214 |
CB-11 |
[0081] The produced cigarettes CA-7 to CA-12 and CB-7 to CB-11 were subjected to the smoking
test according to the same procedure as Example 1. The smoking test was also performed
on the cigarette rod (control cigarette) obtained by removing the filter of the commercially
available filter-tipped cigarette "Seven Stars Solid Menthol".
[0082] The sample for analysis obtained in the smoking test was used to analyze tar, nicotine,
and the semivolatile components according to the same procedure as Example 1. The
permeability (%) and the selective filtration coefficient (%) were calculated according
to the same numerical formulae described in Example 1.
[0083] The permeability and selective filtration coefficient of the typical semivolatile
components of the cigarettes CA-7 to CA-12 and CB-7 to CB-11 are shown in Tables 11A
to 11C below with respect to each total outer peripheral surface area of the cellulose
acetate fiber.
[Table 11A]
Table 11A: Permeability and selective filtration coefficient of typical semivolatile
components |
Filter |
CA-7 |
CA-8 |
CA-9 |
Permeability (%) |
20 |
28 |
32 |
Selective permeation coefficient (%) |
316 |
244 |
193 |
[Table 11B]
Table 11B: Permeability and selective filtration coefficient of typical semivolatile
components |
Filter |
CA-10 |
CA-11 |
CA-12 |
Permeability (%) |
27 |
30 |
35 |
Selective permeation coefficient (%) |
252 |
220 |
192 |
[Table 11C]
Table 11C: Permeability and selective filtration coefficient of typical semivolatile
components |
Filter |
CB-7 |
CB-8 |
CB-9 |
CB-10 |
CB-11 |
Permeability (%) Selective permeation coefficient (%) |
26 285 |
31 221 |
44 159 |
28 256 |
42 162 |
[0084] The permeability of the typical semivolatile components of the cigarettes CA-7 to
CA-12 and CB-7 to CB-11 is shown in FIGS. 8A to 8C with respect to each total outer
peripheral surface area of the cellulose acetate fiber.
[0085] FIG. 8A shows the permeability of the typical semivolatile components of the filters
containing cellulose triacetate particles in the case where the total outer peripheral
surface area of the cellulose acetate fiber is 223 cm
2 (the specification of the fiber tow: 5.0Y35000). FIG. 8B shows the permeability of
the typical semivolatile components of the filters containing cellulose triacetate
particles in the case where the total outer peripheral surface area of the cellulose
acetate fiber is 255 cm
2 (the specification of the fiber tow: 3.5Y35000). FIG. 8C shows the permeability of
the typical semivolatile components of the filters containing cellulose particles
in the case where the total outer peripheral surface area of the cellulose acetate
fiber is 206 cm
2 (the specification of the fiber tow: 5.9Y35000 and 5.0Y35000).
[0086] From the results of Tables 11A to 11C and FIGS. 8A to 8C, it is confirmed that when
the filters having almost the same total outer peripheral surface area of the cellulose
acetate fiber are compared to one another, the permeability of the typical semivolatile
components is high in the filters having a small addition amount of the plasticizer.
This is because the amount of adsorption of the semivolatile components to the surface
of the cellulose acetate fiber is increased by the plasticizer. Therefore, the permeation
of the semivolatile components can be further improved by decreasing the addition
amount of the plasticizer or not adding the plasticizer, in addition to adding the
filtration rate control particles (i.e., cellulose triacetate particles or cellulose
particles) to a filter.
Example 7
[0087] In order to examine the influences of the additives on the filtration performance
of the filtration rate control particles, cellulose particles and the cellulose particles
containing the additives described in Table 12 below were prepared. The cellulose
particles were prepared by the same procedure as Example 6. The cellulose particles
containing the additives were prepared by mixing the additives and cellulose powder
according to the same procedure as Example 6. The additives were added in amounts
described in Table 12. In Table 12, the "addition amount" is represented by a ratio
(% by weight) of the additives to the total weight of the filtration rate control
particles and the additives. The filtration rate control particles not containing
the additives were also prepared for comparison.
[Table 12]
Table 12: Additive-added filtration rate control particles |
Filtration rate control particle Nos. |
Additives |
Addition amount (%) |
A-1 |
- |
- |
B-1 |
L-arginine |
5 |
B-2 |
L-alanine |
5 |
B-3 |
L-glutamic acid |
5 |
B-4 |
Lignin |
10 |
B-5 |
Powder sugar |
2 |
B-6 |
Pectin |
10 |
B-7 |
Sorbitol |
5 |
<Production of filter plug>
[0088] In order to evaluate the filtration performance of the filtration rate control particles,
the filtration rate control particles A-1 and B-1 to B-7 were used to produce filter
plugs F-A-1 and F-B-1 to F-B-7. As shown in FIG. 9A, the filtration rate control particles
were arranged in a paper tube having a length of 25 mm. Acetate filters (5 mm) were
placed at the front side (the side of a tobacco rod) and the rear side (the side of
a filter mouthpiece) of the filtration rate control particles so as to cover the filtration
rate control particles. Thus, filters filled with the filtration rate control particles
were produced. The addition amounts of the filtration rate control particles are shown
in Table 13. As shown in FIG. 9B, a filter plug F-C-1 having two acetate filters (5
mm) arranged in a paper tube having a length of 25 mm was produced as a control. The
specification of each of the filters is shown in Table 13.
[Table 13]
Table 13: Specification of filters |
Filter Nos. |
Filtration rate control particle Nos. |
Addition amount (mg) |
Draw resistance of filter (mmH2O) |
Draw resistance of filtration rate control particles (mmH2O) |
F-A-1 |
A-1 |
100 |
68 |
54 |
F-B-1 |
B-1 |
100 |
55 |
41 |
F-B-2 |
B-2 |
100 |
53 |
39 |
F-B-3 |
B-3 |
100 |
51 |
37 |
F-B-4 |
B-4 |
100 |
50 |
36 |
F-B-5 |
B-5 |
100 |
64 |
50 |
F-B-6 |
B-6 |
100 |
69 |
55 |
F-B-7 |
B-7 |
100 |
53 |
39 |
F-C-1 |
- |
- |
14 |
- |
<Production of test cigarette>
[0089] The commercially available filter-tipped cigarettes "Seven Stars Solid Menthol" were
used for the preparation of test cigarettes. The filter of the commercially available
cigarettes was removed. The resultant cigarette rod was connected to each of the filters
(F-A-1, F-B-1 to F-B-7, and F-C-1) to produce test cigarettes. In this regard, the
filter ventilation was set to 0. The cigarette prepared by using the filter F-C-1
is a control cigarette.
<Smoking test>
[0090] The produced cigarettes were subjected to the smoking test according to the same
procedure as Example 1. The sample for analysis obtained in the smoking test was used
to analyze tar, nicotine, and the semivolatile components according to the same procedure
as Example 1. The permeability (%) and the selective filtration coefficient (%) were
calculated according to the same numerical formulae described in Example 1.
[0091] The permeability and selective filtration coefficient of the typical semivolatile
components of the cigarettes obtained by using the filters F-A-1 and F-B-1 to F-B-7
are shown in Table 14 below.
[Table 14]
Table 14: Permeability and selective filtration coefficient of typical semivolatile
components |
Filter |
F-A-1 |
F-B-1 |
F-B-2 |
F-B-3 |
F-B-4 |
F-B-5 |
F-B-6 |
F-B-7 |
Permeability (%) |
68 |
67 |
73 |
72 |
74 |
69 |
68 |
72 |
Selective permeation coefficient (%) |
98 |
105 |
98 |
100 |
101 |
100 |
98 |
99 |
[0092] The permeability of the typical semivolatile components of the cigarettes obtained
by using the filters F-A-1 and F-B-1 to F-B-7 is shown in FIG. 10.
[0093] From the results of Table 14 and FIG. 10, it can be confirmed that the permeability
of the semivolatile components by the filtration rate control particles contained
in each filter is constant regardless of the presence or absence of the additive or
the kind of the additive. From this result, the following could be confirmed. Even
if the additive contributing to cigarette smoking flavor is added to the filtration
rate control particles, a small amount thereof does not have any influence on the
filtering characteristics of the filtration rate control particles.
List of Reference Signs
[0094] 10 ... cigarette, 110 ... cigarette rod, 111 ... cigarette paper, 112 ... tobacco
filler, 120 ... filter, 121 ... filter plug, 122 ... cellulose acetate fiber tow,
123 ... cellulose acetate fiber, 124 ... filtration rate control particles, 125 ...
filter wrapping paper, 130 ... tipping paper, 131 ... ventilation hole, 140 ... acetate
plain filter plug, 141 ... filter wrapping paper, 142 ... cellulose acetate fiber
tow