Patent Application
20130247925
1. Field of the Invention
This invention relates to a cigarette paper and a cigarette, and more specifically relates to a cigarette paper and a cigarette reducing a visible sidestream smoke amount and a carbon monoxide amount in mainstream smoke.
2. Description of the Related Art
Recently, a cigarette (low sidestream smoke cigarette) having a small amount of sidestream smoke to be generated has been developed. Whether such a cigarette actually has a small amount of sidestream smoke to be generated is usually determined by a so-called fishtail method (described in Health Canada Test Method T-212). In this fishtail method, the amount of total particulate matter in sidestream smoke is measured, and the amount of the total particulate matter is considered as a sidestream smoke amount.
In order to provide a cigarette having a small amount of sidestream smoke to be generated, a filler which is a compound exhibiting combustion inhibiting effect is added to a cigarette paper. For example, Patent Document 1 discloses that magnesium hydroxide gel is added, and Patent Document 2 discloses that a filler having a high-specific surface area formed of calcium carbonate and so on is added.
Meanwhile, Patent Document 3 discloses a cigarette paper which can reduce the sidestream smoke amount according to visual observation (also referred to as the visible sidestream smoke amount in this specification) rather than the sidestream smoke amount according to the fishtail method. This cigarette paper contains calcium carbonate in an amount of 30 g/m2 or more and a combustion regulating agent such as potassium citrate in an amount of 3% by weight or more.
Although the low sidestream smoke cigarette according to the prior art significantly reduces the sidestream smoke amount, there is a tendency to increase the carbon monoxide amount in the mainstream smoke.
Accordingly, an object of the invention is to provide a cigarette paper which can reduce a visible sidestream smoke amount and at the same time can reduce a carbon monoxide amount in a mainstream smoke.
In order to solve the above problem, this invention provides a cigarette paper having a grammage of 40 to 55 g/m2 and containing calcium carbonate in an amount of 18 g/m2 or more.
This invention further provides a cigarette including a cigarette rod including tobacco shreds wrapped into a rod shape with the cigarette paper, and a filter coaxially connected to an end of the cigarette rod by a tipping paper.
A cigarette paper and a cigarette according to this invention reduce the amount of sidestream smoke generated and the amount of carbon monoxide in main stream smoke.
Hereinafter, the present invention will be explained in detail.
The cigarette paper according to this invention has a grammage of 40 to 55 g/m2 and contains calcium carbonate in an amount of 18 g/m2 or more.
Pulp fiber used in the cigarette paper according to this invention can be constituted of flax pulp fiber used in a typical cigarette paper, wood pulp fiber (hardwood pulp, softwood pulp), and so on.
The cigarette paper according to this invention is prepared by mixing 18 g/m2 or more of calcium carbonate with the pulp fiber. Calcium carbonate is contained in the form of particles, and although the particle diameter can be suitably selected in terms of cost and ease of papermaking, the particle diameter is preferably 0.02 to 10 μm. The content of calcium carbonate is preferably 29 g/m2 or less. The content of calcium carbonate is more preferably 20 to 25 g/m2. In this specification, the content of calcium carbonate means the amount of calcium carbonate contained in a cigarette paper after manufacture. The amount of calcium carbonate in the cigarette paper can be obtained by extracting and then quantifying calcium ions as described in an example to be described later.
Calcium carbonate used in this invention is a synthetic calcium carbonate synthesized by chemical reaction, and primary particles of the synthetic calcium carbonate are all in substantially the same shape and size and are homogeneous. In this specification, the term “primary particles” refers to fundamental particles constituting a power immediately after synthesis by chemical reaction, and the term “secondary particles” refers to an aggregate formed by agglomeration of a large number of primary particles.
The shape of the primary particles of calcium carbonate to be used is not particularly limited, and the primary particles having any shape of a spindle shape, a cubic shape, a columnar shape, and a needle shape can be used. However, when calcium carbonate in which the primary particles have a columnar shape or a needle shape is used, the amount of carbon monoxide in mainstream smoke is significantly reduced in comparison with the case of using calcium carbonate having another shape.
The width (W) and the length (L) of the primary particle can be measured using a scanning electron microscope, for example.
In a preferred aspect, in the calcium carbonate used in this invention, it is preferable that the primary particle has a columnar shape or a needle shape, and, at the same time, the shape of the secondary particle formed by agglomeration in a process of typical papermaking has a bur shape. The bur shape represents an agglomeration shape in which tens to thousands of primary particles having a columnar or needle shape are three-dimensionally entangled. As a specific example of the bur shape, there are aspects shown in Jpn. Pat. Appln. KOKAI Publication Nos. 55-40849 and 59-94700.
When calcium carbonate in which the secondary particles are in the form of a bur shape is used, calcium carbonate in the form of the primary particle (having a columnar or needle shape) may be contained in pulp fiber, calcium carbonate in the form of the secondary particle (having a bur shape) may be contained in the pulp fiber, or calcium carbonate as a mixture having the forms of the primary particle and the secondary particle may be contained in the pulp fiber. In each case, calcium carbonate has a bur shape in the cigarette paper.
In this invention, preferably, the primary particles of calcium carbonate have a columnar or needle shape. More preferably, an average aspect ratio of the primary particles falls within the range of not less than 4 and less than 10, and an average length (L) of the primary particles is 0.1 to 1.5 μm. It is still more preferable that the density of the obtained cigarette paper is 0.4 to 1.0 g/m3.
To obtain the average aspect ratio, representative plural (at least 50, and for example, 50 to 200) particles are selected, the aspect ratio is obtained by measuring the width (W) and the length (L) of the primary particles for each particle, and an average value of the aspect ratio is obtained, whereby the average aspect ratio can be obtained. To obtain the average length (L), representative plural (at least 50, and for example, 50 to 200) particles are selected, the length (L) of each particle is measured, and an average value of the length (L) is obtained, whereby the average length (L) can be obtained.
The cigarette paper according to this invention has a grammage of 40 to 55 g/m2. It is more preferable that the grammage of the cigarette paper is 42 to 50 g/m2.
The cigarette paper according to this invention may contain a combustion regulating agent. As the combustion regulating agent, an alkali metal citrate is preferably used, and particularly preferred are potassium citrate and sodium citrate, and these combustion regulating agents may be used alone or may be used in combination. The cigarette paper preferably contains the combustion regulating agent in an amount of 1.0 to 5.0% by weight, and more preferably 1.5 to 4.0% by weight.
The cigarette paper according to this invention reduces the amount of visible sidestream smoke of a cigarette and, at the same time, can reduce the amount of carbon monoxide in mainstream smoke in comparison with a conventional cigarette paper.
The cigarette paper according to this invention can be used as a cigarette paper of a cigarette with a filter. Namely, according to one aspect of this invention, there is provided a cigarette which includes a cigarette rod including tobacco shreds wrapped into a rod shape with the cigarette paper of the invention and a filter coaxially connected to an end of the cigarette rod by a tipping paper.
The amount of carbon monoxide in mainstream smoke can be measured as the carbon monoxide amount per smoke draft obtained by dividing the total amount per cigarette in specified cigarette smoking conditions (Health Canada Test Method: 55 ml/2 s) by the total number of smoke drafts.
Although the amount of visible sidestream smoke can be measured by sensory evaluation, the amount of visible sidestream smoke can be simply measured using a visible sidestream smoke amount measuring apparatus disclosed in Japanese Patent No. 3683792 (or Patent Literature 3). The visible sidestream smoke amount measuring apparatus will be hereinafter described using
As shown in
The spontaneous combustion chamber 11 is formed of a light-shielding material and constituted of a rectangular parallelepiped tubular body elongated in a longitudinal direction prescribed by four sidewalls 11a to 11d, for example. Sidewall 11a has in its lower portion a smoking article insertion opening 111 through which a smoking article SA such as a lit cigarette is fitted in the spontaneous combustion chamber 11. The four sidewalls 11a to 11d prescribing the spontaneous combustion chamber 11 respectively have ventilation windows 112 to 115 such as mesh windows at their lowermost end portions so that air required for spontaneous combustion of the smoking article SA can be supplied in the spontaneous combustion chamber 11. It is preferable that the position of the insertion opening 111 for a smoking article is set to a position where sidestream smoke SSS from the smoking article SA fitted in the spontaneous combustion chamber 11 through the insertion opening 111 passes through the ventilation windows 112 to 115 is not affected by disturbance of outside air entering inside the spontaneous combustion chamber 11, and a distance from the smoking article SA to the upper end of the spontaneous combustion chamber 11 is sufficient such that the sidestream smoke SSS is not substantially swayed.
Glass beads (not shown) are filled in a bottom space of the spontaneous combustion chamber 11 surrounded by the ventilation windows 112 to 115 so that the flow of the sidestream smoke SSS rising in the spontaneous combustion chamber 11 due to spontaneous combustion of the smoking article is not disturbed, whereby an air flow rectifying layer can be formed. The upper end of the spontaneous combustion chamber 11 is opened. An exhaust hood 15 can be installed at the open end for the purpose of exhausting in the spontaneous combustion chamber 11. The spontaneous combustion chamber 11 is required to be exhausted so as to avoid substantial influence on the spontaneous combustion of the smoking article SA. In the event of exhaust, in order to prevent the disturbance of the flow of the sidestream smoke SSS naturally rising in the spontaneous combustion chamber 11 due to the spontaneous combustion of the smoking article, it is preferable that a rectification filter 16 is attached across an upper open end of the spontaneous combustion chamber 11.
The exhaust hood 15 has an exhaust duct 151 on its top, and the exhaust duct 151 is connected to an exhaust system (not shown).
The visible light emitting unit 12 is provided outside the spontaneous combustion chamber 11. In an example shown in
The visible light beam (visible light flux) VLB emitted from the visible light emitting unit 12 has a substantial cross-sectional surface in which the visible light can be applied to the sidestream smoke SSS naturally rising in the spontaneous combustion chamber 11 while, even if the sidestream smoke SSS is somewhat swayed, the sway is sufficiently covered. For example, the visible light beam VLB has a width w (
It is preferable that a light absorption unit 13 used for absorbing/removing all light emitted from the visible light emitting unit 12 and transmitted through the sidestream smoke SSS so that measurement is not affected is provided outside the spontaneous combustion chamber 11 facing the visible light emitting unit 12 and, in the example shown in
A scattered light intensity detection unit 14 is provided outside the spontaneous combustion chamber 11 in the direction perpendicular to the direction of the light beam emitted from the light intensity detection unit 12, and in an example shown in
The detected intensity of the 90 degree scattered light SVL correlates very well with the amount of visible sidestream smoke, and as the detected intensity of the 90 degree scattered light is large, it can be determined that the amount of visible sidestream smoke is relatively large. It was shown that the intensity of the 90 degree scattered light does not correlate with the total amount of particulate matter in the sidestream smoke.
It is preferable to install external stray light shielding boxes 17 to 19 between the visible light emitting unit 12 and the visible light transmission window 116, between the light absorbing unit 13 and the visible light transmission window 117, and between the scattered light intensity detection unit 14 and the visible light transmission window 118 in order to prevent external stray light from entering through each visible light transmission window.
When a representative example of the entire size of an apparatus 10 and so on are shown, the spontaneous combustion chamber 11 has a rectangular solid shape of 11 cm×11 cm having a height of 80 cm, and the smoking article insertion opening 111 is provided at a position of 50 cm from the lower end of the spontaneous combustion chamber 11, a distance from the smoking article SA to the center of visible light beam is 10 cm, and the visible light beam emitted from the visible light emitting unit has a cross section with a size of 5 cm×5 cm.
As shown in
The sensory evaluation according to the two-point comparison method can be performed using a visible sidestream smoke amount evaluation apparatus shown in
The 90 degree scattered light intensity obtained by the visible sidestream smoke amount measuring apparatus correlates very well with amount of the visible sidestream smoke in the sensory evaluation, and this fact is demonstrated in Japanese Patent No. 3897700. In this invention, when the sensory evaluation according to the two-point comparison method is performed using the visible sidestream smoke amount evaluating apparatus shown in
Hereinafter, the invention will be described with reference to examples. In the following examples, calcium carbonate PCX-850 and Cal-light-SA were purchased from Shiraishi Kogyo Kaisha, Ltd., and needle-shaped calcium carbonate and bur-shaped calcium carbonate were purchased from Newlime Co., Ltd.
The primary particle of PCX-850 has a spindle shape, and although the primary particles form the secondary particle, a bur shape is not formed. The primary particle of Cal-light-SA has a columnar shape, and the primary particles are agglomerated to form a bur-shaped secondary particles. The primary particle of the needle-shaped calcium carbonate has a needle shape, and the primary particles does not form the secondary particle. The primary particle of bur-shaped calcium carbonate has a needle shape, and the primary particles are agglomerated to form the bur-shaped secondary particle.
A pulp mixture in which the weight ratio of bleached broad leaf tree kraft pulp (LBKP) to bleached coniferous tree kraft pulp (NBKP) is 8:2 is beaten so that a freeness is about 100 mL in Canadian Standard Freeness, and calcium carbonate shown in Table 1 as a filler is added to the beaten pulp mixture in a content shown in Table 1. With the use of an obtained paper stock, a cigarette paper (the grammage is shown in Table 1) is subjected to papermaking by a TAPPI standard sheet machine. Potassium citrate aqueous solution as a combustion regulating agent is coated onto a surface of the obtained cigarette paper so that potassium citrate in an amount of 3 to 4 wt % on the dry base is contained in the cigarette paper. This cigarette paper is matched for two or more days under conditions of a temperature of 22° C. and a relative humidity of 60% and cut into a predetermined length. In the amount of calcium carbonate in the cigarette paper, ultrasonic extraction is performed for 30 minutes in 0.3 N aqueous hydrochloric acid, and calcium carbonate is quantified as calcium ions by a capillary electrophoresis system (7100) manufactured by Agilent Technologies, and calcium ions are converted into calcium carbonate, whereby the amount of calcium carbonate in the cigarette paper is obtained.
With the use of the obtained cigarette paper and tobacco shreds (American blend), a cigarette is produced by a tobacco roller (Rizla). As the size of the cigarette, the circumference is 22.6 mm, and the length is 67 mm. A normal filter (having a length of 31 mm) is provided to be mounted on one end of the cigarette with the use of a tipping paper. The filling amount of the tobacco shreds is 0.515 g per cigarette.
The amount of visible sidestream smoke of the obtained cigarette is measured using an apparatus shown in
In the measurement of the amount of visible sidestream smoke, in order to correct the difference between days in sensitivity of a visible laser, for each measurement, the amount of visible sidestream smoke of each cigarette is standardized with a visible sidestream smoke amount measured value in a standard cigarette (reference cigarette 3R4F) (accordingly, the unit is nondimensional). In order to eliminate influence of the grammage of the cigarette paper and the kind and content of calcium carbonate, the standardized amount of visible sidestream smoke is divided by the spontaneous combustion rate (SBR) (unit: mm/min) of a cigarette. SBR is measured at an atmosphere linear velocity of 200 mm/s. The results are indicated in Table 1.
The reference example is an example of using calcium carbonate (Unibur-70) (although it is not available now, it is stored by the present applicant) described in Jpn. Pat. Appln. KOKAI Publication No. 59-94700.
As can be seen in the result shown in Table 1, it is confirmed that if the content of calcium carbonate is not less than 18 g/m2, the value of the visible sidestream smoke amount per spontaneous combustion rate (SBR) is less than 5.0×10−2. This fact shows that the visible sidestream smoke is sufficiently reduced (examples 1 to 4). Meanwhile, It will be shown that when the amount of calcium carbonate is less than 18 g/m2, including the reference example, the amount of visible sidestream smoke is large (comparative examples 1 and 2).
Although the yield of calcium carbonate with respect to the amount of pulp in the cigarette paper depends on the amount of pulp, it is considered that the maximum value is 40 to 60%, and when the yield is 40 to 50%, the grammage of the cigarette paper required for maintaining not less than 18 g/m2 of calcium carbonate is assumed to be not less than 40 g/m2. When the content of calcium carbonate is further increased, the grammage is required to be increased, and accompanying this, the amount of carbon monoxide in the sidestream smoke is increased. Specifically, it can be confirmed from the comparative example 3, that when the grammage is more than 55 g/m2, although there is a tendency to reduce the amount of visible sidestream smoke, the amount of carbon monoxide in the mainstream smoke is increased.
According to above, when the cigarette paper has a grammage of 40 to 55 g/m2 and contains calcium carbonate in an amount of not less than 18 g/m2, the amount of sidestream smoke generated and the amount of carbon monoxide in the mainstream smoke can be reduced. As shown in the comparative example 2, when the cigarette paper has a grammage of 42 to 50 g/m2 and contains calcium carbonate in an amount of 20 to 25 g/m2, it is possible to expect greater effects.
In the examples 5 and 6, in calcium carbonate in which the primary particles have comparable length (L) and the shapes of the primary particles are different, the influence of the shape of the primary particles on the amount of visible sidestream smoke and the mainstream smoke is examined. As calcium carbonate in which the primary particles have different shapes, PCX-850 and Cal-light-SA are used. The contents of PCX-850 and Cal-light-SA are 22.5 and 23.0 g/m2, respectively.
A cigarette paper is manufactured as in the above examples to produce a cigarette except that the grammage of the cigarette paper and the kind of calcium carbonate are changed as shown in the following Table 2. The amount of visible sidestream smoke and the amount of carbon monoxide in the main stream smoke of the obtained cigarette are measured. Further, with regard to the obtained cigarette paper, in order to examine a mechanism in which the amount of carbon monoxide in the main stream smoke is reduced, the density of the cigarette paper is measured. The results are shown in Table 2.
The length (L) of the primary particle described in Table 2 is an average of the length (L) of 100 primary particles measured by means of Winroof image analysis software (Mitani Corporation) using an SEM image captured with a JSM-5310 scanning electron microscope manufactured by JEOL. Although the aspect ratio of calcium carbonate used in this example is indicated in Table 2, the width (W) of the primary particle is measured in a similar manner to the length (L) of the primary particle, and the ratio (L/W) of the length (L) of the primary particle to the width (W) is calculated.
As can be seen in the result shown in Table 2, when the calcium carbonate in which the primary particles have a columnar shape and the calcium carbonate in which the primary particles have a spindle shape are compared with each other, the amount of carbon monoxide in the main stream smoke of the cigarette paper using the columnar calcium carbonate is lower, and therefore, it is confirmed that the shape of the primary particle is important. With regard to the density of the cigarette paper, in comparison with the cigarette paper using the calcium carbonate in which the primary particles have a spindle shape, when the calcium carbonate in which the primary particles have a columnar shape is used, the reduction of the cigarette paper density can be confirmed. When the calcium carbonate (Cal-light-SA) in which the primary particles have a columnar shape is used, it is assumed that the density of the cigarette paper is reduced, so that the amount of carbon monoxide in the mainstream smoke is reduced. When a limitation in manufacturing at present is considered, a suitable aspect ratio (L/W) of the columnar or needle-shaped calcium carbonate is preferably not less than 4 and less than 10. When Cal-light-SA is used, the visible sidestream smoke falls within a range of not more than 5.0×10−2 (min/mm), and therefore, it can be said that the amount of visible sidestream smoke can be sufficiently reduced.
Next, in calcium carbonate in which the secondary particles similarly have a bur shape, the influence of the length (L) of the primary particle on the amount of visible sidestream smoke and the amount of carbon monoxide in the mainstream smoke is examined. As calcium carbonate having columnar or needle-shaped primary particles having different length (L), bur-shaped calcium carbonate and Cal-light-SA are used.
A cigarette paper is manufactured as in the above examples to produce a cigarette except that the grammage of the cigarette paper and the kind of calcium carbonate are changed as shown in the following Table 3. The amount of visible sidestream smoke and the amount of carbon monoxide in the main stream smoke of the obtained cigarette are measured. The results are indicated in Table 3. The length (L) of the primary particle described in Table 3 is an average of the length (L) of 100 primary particles measured according to the above method. The primary particles of bur-shaped calcium carbonate have an average aspect ratio of 6.7, and the primary particles of Cal-light-SA have an average aspect ratio of 9.5.
As can be seen in the result shown in Table 3, in the cigarette paper using two kinds of calcium carbonate in which the secondary particles similarly have a bur shape, it is confirmed that the amount of carbon monoxide in the main stream smoke in the cigarette paper using Cal-light-SA in which the length (L) of the primary particles is small is further reduced. Thus, it can be shown that the smaller the size of the primary particle, the larger the effect of reducing the amount of carbon monoxide in the mainstream smoke, and considering variation of the length (L) of the primary particles, it is assumed that the average length (L) of the primary particles is preferably not more than 1.5 μm.
The influence of whether or not the secondary particles of calcium carbonate are in the form of a bur shape on the amount of visible sidestream smoke and the amount of carbon monoxide in the mainstream smoke is examined.
A cigarette paper is manufactured as in the above examples to produce a cigarette except that the grammage of the cigarette paper and the kind of calcium carbonate are changed as shown in the following Table 4. The amount of visible sidestream smoke and the amount of carbon monoxide in the mainstream smoke of the obtained cigarette are measured. The results are indicated in Table 4. In the bur-shaped calcium carbonate used here, the primary particles have a needle shape, the average length (L) of the primary particles is 3.3 μm, the average aspect ratio of the primary particles is 8.0, and the secondary particles have a bur shape. Meanwhile, in the needle-shaped calcium carbonate, the primary particles have a needle shape, the average length (L) of the primary particles is 4.8 μm, and the average aspect ratio of the primary particles is 6.7; however, the secondary particles does not have a bur shape. Thus, the bur-shaped calcium carbonate and the needle-shaped calcium carbonate in which the values of the lengths (L) of the primary particles are approximately close to each other are compared, whereby the influence of whether or not the secondary particles are in the form of a bur shape on the amount of visible sidestream smoke and the amount of carbon monoxide in the mainstream smoke can be verified.
As can be seen in the result shown in Table 4, in the cigarette paper using bur-shaped calcium carbonate in which the secondary particles have a bur shape, although the amount of visible sidestream smoke is substantially equivalent in comparison with the cigarette paper using needle-shaped calcium carbonate, the amount of carbon monoxide in the mainstream smoke is reduced. From this fact, the effect obtained when the calcium carbonate in which the secondary particles have a bur shape is used is confirmed. However, in the cigarette paper containing calcium carbonate in which the primary particles have a large length (L), since the density of the cigarette paper is not reduced, the effect of reducing the amount of carbon monoxide in the mainstream smoke can be less expected, and as the length (L) of the primary particles becomes small, the higher the carbon monoxide reduction effect that can be expected. Namely, in the cigarette paper using calcium carbonate in which the primary particles have a columnar shape or needle shape, the size of the primary particles is small, and the secondary particles have a bur shape, it is guessed that the density of the cigarette paper is reduced most, and the carbon monoxide amount in the mainstream smoke is reduced most.
In this example, although a cigarette having a circumference of 22.6 mm is used, a similar effect can be expected in a cigarette having a different circumference, and the invention does not limit the size of a cigarette.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-077902 | Mar 2011 | JP | national |
This application is a Continuation application of PCT Application No. PCT/JP2012/058622, filed Mar. 30, 2012 and based upon and claiming the benefit of priority from prior Japanese Patent Application No. 2011-077902, filed Mar. 31, 2011, the entire contents of all of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2012/058622 | Mar 2012 | US |
| Child | 13895995 | US |
