JP2000000085A - Cigarette with filter of double concentric structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cigarette with a filter designed to set CO/tar ratio at <=0.6 while maintaining both tar levels and product air permeation resistance at proper values, respectively. SOLUTION: This cigarette with a filter has such design that a cigarette rod 10 and a filter plug 20 of double concentric structure are mutually connected via a chip paper perforated with ventilation holes 301; wherein the core 211 of the filter plug is wrapped with an air-impermeable film 212 whose coefficient of air permeation resistance is set 0.1- to 0.8-fold that of the filter sheath 213; further, the ventilation holes are set at a point separated apart from the foot end with a length equivalent to 70% of the whole length of the filter plug, and the air inflow rate through the chip paper is set at 30-85%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cigarette with a filter, and more particularly to a cigarette having a double concentric filter with a reduced CO / tar ratio.

[0002]

2. Description of the Related Art In a cigarette with a filter comprising a tobacco rod wound with cigarette paper and a filter plug connected to the tobacco rod, a weight ratio of carbon monoxide (CO) contained in mainstream smoke to tar weight. (CO
/ Tar ratio) is generally 1 or more, and may be as high as about 2.5. In view of such circumstances, there is a demand for a cigarette with a filter having a reduced CO / tar ratio.

[0003] Conventionally, in order to reduce the CO / tar ratio, there is known a technique of using a filter having a low tar filtration efficiency and increasing the filter ventilation.
The use of a filter with low tar filtration efficiency results in a higher tar ratio, which results in a lower CO / tar ratio.
Increasing the filter ventilation also reduces the tobacco burn rate and the tar ratio, but keeps the CO / tar ratio high. Therefore, by combining the two, the CO / tar ratio can be reduced while maintaining the tar amount at a desired value.

[0004] However, the combined use of a filter with low tar filtration efficiency and a technique for increasing the filter ventilation lowers the suction resistance of cigarettes (also referred to as product ventilation resistance in this specification). If the product airflow resistance of the cigarette decreases, the taste changes or worsens, so that the unique taste of each cigarette cannot be maintained.

[0005] In particular, in the case of cigarettes having filter ventilation, in order to maintain good taste, 90 to 1 cigarette is required.
It is said that a suction resistance of 30 mmH ₂ O is required. However, in the cigarette in which the CO / tar ratio is reduced by the above-described conventional method, the taste is deteriorated because the suction resistance does not reach 90 mmH ₂ O.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method for maintaining tar and product airflow resistance at good values.
It is an object of the present invention to provide a cigarette with a filter having a CO / tar ratio set to 0.6 or less.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted intensive studies on cigarettes with a filter. As a result, the present invention has a double concentric structure in which the core is wound with an air-impermeable film. In the filter, the filtration efficiency of the core part is set lower than the filtration efficiency of the sheath part, and the position of the opening (ventilation hole) provided in the tip paper connecting the filter and the tobacco rod is set on the upstream side of the filter. When the rate of air inflow from the ventilation hole is increased by doing so, a part of the air that has flowed in from the ventilation hole flows back, causing all mainstream smoke to flow into the core with low filtration efficiency, and thus the entire filter Can function as a low filtration filter, while maintaining good tar and product airflow resistance, It found that it is possible to reduce Lumpur ratio.

As a result of further research based on this finding, the CO / tar ratio of the tobacco rod itself was 0.65 or less, and the ventilation resistance of the tobacco rod itself was 40 mmH.
_When it is ₂ O or more, the ventilation resistance coefficient of the filter core portion is in the range of 0.1 to 0.8 times that of the filter sheath portion, and the ventilation holes are formed in the filter region in the entire length of the filter. With a length of 70% or more of the length of the tip paper and a hole at a position spaced from the downstream end of the tip paper (the suction end of the filter). It has been found that by setting the content to 30 to 85%, the CO / tar ratio can be reduced to 0.6 or less and the product airflow resistance can be maintained at 90 to 130 mmH ₂ O, thereby completing the present invention.

That is, according to the present invention, there is provided a tobacco rod made of cigarette wrapped around a cigarette; a filter core portion and a filter sheath portion disposed around the core portion and concentrically with the core portion. A filter plug; and a tip paper covering the downstream end of the tobacco rod and substantially the entire peripheral surface of the filter plug and connecting the tobacco rod and the filter plug, and the CO / tar of the tobacco rod itself. The ratio is 0.65 or less, and the ventilation resistance of the tobacco rod itself is 40 mmH ₂ O or more, the filter core is wound with an air-impermeable film, and the ventilation resistance coefficient of the filter core is The tip paper is 0.1 to 0.8 times the airflow resistance coefficient of the filter sheath portion, and the tip paper has an area corresponding to the filter plug. Wherein the ventilation comprises a plurality of ventilation holes having an opening position at a position spaced from the downstream end of the tip paper with a length of 70% or more of the entire length of the filter plug, and formed along the circumferential direction. Characterized by having a row of holes, wherein an air inflow rate from the chip paper is 30 to 85%,
A cigarette having a double concentric filter is provided.

[0010] The cigarette of the present invention is 90-130.
It shows the product airflow resistance of mmH ₂ O and the CO / tar ratio of 0.6 or less.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a perspective view schematically showing an example of a cigarette with a filter of the present invention in a state where a tip paper, a wrapping paper, and a winding paper are developed, and FIG. 2 is a perspective view.
It is sectional drawing of the filter plug of the cigarette with a filter of FIG.

As shown in FIG. 1, a cigarette with a filter according to the present invention comprises a tobacco rod 10 composed of tobacco cuts 11 wound by a wrapper 12,
A filter comprising a double concentric filter plug 20 which is disposed at the downstream end of
A tip paper 30 for connecting the tobacco rod 10 and the filter plug 20 is provided. In the present specification, the terms “downstream” and “upstream” are based on the smoke absorption direction of tobacco.

In the present invention, the cigarette rod 10 is formed by wrapping a regular cigarette cut 11 in the same manner as a regular cigarette.
2 is wound. The wrapping paper 12 around which the tobacco cut 11 is wrapped is wrapping paper used for ordinary cigarettes and has air permeability. In the present invention, the CO / tar ratio in the tobacco rod 10 itself is 0.6.
5 or less, and the ventilation resistance of the tobacco rod 10 itself is 40 mmH ₂ O or more.

The filter plug 20 disposed at the downstream end of the tobacco rod 10 is a double concentric filter plug, which is wound by an air-impermeable film 212 as shown in FIG. Filter core section 21
1 and a filter sheath portion 213 disposed concentrically with the core portion 211 around it.

The filter core portion 211 can be formed of a long fiber tow such as cellulose acetate, polypropylene, or rayon, or a web material disclosed in, for example, JP-A-6-169743.

The filter core portion 211 is wound around an air-impermeable film 212. When the film around which the filter core portion 211 is wound substantially transmits air, the air flowing from the ventilation hole of the chip paper is unlikely to flow backward, and as a result, mainstream smoke flows to the sheath portion having high filtration efficiency, The filtration efficiency of the whole filter becomes high, and the object of the present invention cannot be achieved. In addition, when an air-impermeable wound paper used for a normal cigarette filter is used instead of the air-impermeable film, the paper smell becomes strong and the taste becomes worse. The air impermeable film 212 may be, for example, a resin film such as cellulose acetate, polypropylene, or rayon. By using such a resin film, the above-mentioned problem of deterioration of taste can be avoided. Usually, this film 212
It has a thickness of 5 to 30 μm. Filter core 2
11 may have a circumference of 10 to 20 mm when wound by an air-impermeable film 212.

The filter sheath portion 213 disposed concentrically around the filter core portion 211 via the air-impermeable film 212 can be formed of the same fiber material as the core portion. The wrapping paper 22 around which the filter sheath portion 213 is wrapped may be the same as the wrapping paper applied to a normal cigarette filter, has relatively high air permeability, and is preferably 10,000.
Milliliter (mL) / cm ² · minute · 100 mmH ₂ O
With a permeability of above, most preferably 20,000 mL
/ Cm ² · min · 100 mmH ₂ O or more. If the air permeability of the wrapping paper is low, the inflow ratio of air from the ventilation holes becomes 30% or less, and the intended object of the present invention cannot be achieved. The filter sheath portion 213 is wound 23 to 27 m
m may have a circumference. In the present invention, the web 22 may be omitted. In that case, the sheath 21
It is preferable that the fiber material forming 3 has the same air permeability as the above-described web paper 22.

The double concentric filter plug of the present invention can have a length of 15 to 40 mm, like a normal cigarette filter.

In the present invention, the ventilation resistance coefficient of the filter core portion 211 is 0.1 to 0.8 times the ventilation resistance coefficient of the filter sheath portion 213. In the present invention, the ventilation resistance coefficient Rc of the filter core portion is determined by extracting the core portion from the filter plug having a double concentric structure, and using the extracted core portion with an impermeable tube so that air does not flow in from the side surface. Cover, 17.5 per second
The differential pressure of the core portion when sucked at a flow rate of cm ³ is Pc (m
mH ₂ O), the cross-sectional area of the core portion is Ac (cm ² ), and the length of the core portion (the length of the filter plug) is L (cm): Rc = Ac · Pc / (17.5 L) ). On the other hand, the ventilation resistance coefficient Rs of the filter sheath portion is determined by measuring the sheath when the core portion is replaced with an air-impermeable plastic rod in a double concentric filter plug, and this plug is sucked at a flow rate of 17.5 cm ³ per second. Assuming that the differential pressure of the portion is Ps (mmH ₂ O), the cross-sectional area of the sheath portion is As (cm ² ), and the length of the sheath portion (the length of the filter plug) is L (cm), the following formula: Rs = As -It is represented by Ps / (17.5L).

As described above, in the present invention, the ventilation resistance coefficient (hereinafter, also referred to as PD) of the filter core portion 211 is 0.1 to 0.8 times the PD of the filter sheath portion 213, ie, the core / Sheath PD ratio is 0.1
Or 0.8. This PD ratio is between 0.1 and 0.
8, the lower the value, in other words, the lower the filtration efficiency of the core portion than the filtration efficiency of the sheath portion, the part of the air flowing from the ventilation holes formed in the tip paper. And all the mainstream smoke is caused to flow into the core portion having low filtration efficiency, so that the entire filter can function as a low filtration filter. The core / sheath PD ratio is particularly preferably 0.1 to 0.5.

The tip paper 30 is made of the tobacco rod 10.
The tobacco rod 10 and the filter plug 20 are connected so as to cover the downstream end of the filter plug and almost the entire peripheral surface of the filter plug 20. This tipping paper has a length of 7 times the entire length of the filter plug in the area corresponding to the filter plug.
A ventilation hole row including a plurality of ventilation holes 301 formed along the circumferential direction at a position separated from the downstream end (corresponding to the suction end of the filter plug 20) of the tip paper 30 with a length of 0% or more is provided. Have. In FIG. 1, only one ventilation hole row is formed, but a plurality of ventilation hole rows may be provided.

The method for forming the ventilation holes 30 is not particularly limited. For example, a ventilation hole can be mechanically or electrically formed in the chip paper in advance. Alternatively, after providing the tip paper having no ventilation holes on the peripheral surfaces of the filter and the tobacco rod, the ventilation holes can be formed by, for example, a laser.

In the present invention, the ventilation holes 30
The opening position of 1 is the position of the ventilation hole 301 formed in the tip paper in the longitudinal direction of the filter plug 20, and when the ventilation hole 301 is formed in one row as shown in FIG. This is the position of the center of the hole. In the case where ventilation holes are formed in a plurality of rows, it is the center position in the length direction of the filter between the two furthest (ie, two outside) ventilation rows. That is, the opening position in this case indicates an opening position. As the opening position is closer to the tobacco rod, the air flowing from the ventilation hole tends to flow backward and the product ventilation resistance tends to increase. As described above, the bench is located at a position 70% or more of the length of the filter plug. The intended purpose can be achieved by the presence of the ration holes. It is particularly preferable that the ventilation hole 301 is formed at a position apart from the suction end with a distance corresponding to about 75% or more of the entire length of the filter.

In the present invention, the rate of air inflow from the ventilation hole is 30 to 85%.
Here, the air inflow ratio (also referred to as Vf or filter ventilation) refers to the flow rate of air introduced into the cigarette through the tip paper with respect to the flow rate at the suction end when the cigarette is sucked at a standard flow rate of 17.5 cm ³ / sec. Is expressed as a percentage. This air inflow ratio is particularly preferably 50 to 85%.

The cigarette having the double concentric filter of the present invention satisfying the above conditions can (a) reduce the CO / tar ratio to 0.6 or less and (b) have a product airflow resistance of 90 to 130 mmH _2. O.

Here, the CO / tar ratio refers to the weight ratio of carbon monoxide (CO) contained in mainstream smoke to tar. Here, tar refers to a granular substance excluding water and nicotine.

The product airflow resistance is a differential pressure when suction is performed at a flow rate of 17.5 cm ³ / sec without blocking a ventilation hole on a filter side surface of a cigarette, and the unit is mmH ₂ O.

Thus, the cigarette provided with the double concentric filter of the present invention has a product airflow resistance of 90 m.
The CO / tar ratio can be reduced to 0.6 or less while maintaining the mH ₂ O or more.
A low cigarette / tar ratio results.

When smoking a cigarette provided with the filter of the double concentric structure of the present invention, the mainstream smoke is the tobacco rod 1
After that, it flows through the filter plug 20. At this time, the surrounding air flows into the sheath portion 213 of the filter plug 20 from the ventilation hole 301 formed in the chip paper 30, but the air-impermeable film 21
2 and does not flow into the core portion 211. Most of the air that has flowed into the sheath portion 213 flows in the sheath portion 213 toward the mouth end of the plug, but a part of the air flows backward, so that the mainstream smoke from the tobacco rod 20 is exclusively the core portion 211. To flow to.

[0031]

EXAMPLES The results of tests performed to confirm the effects of the cigarette with a filter having a double concentric aperture according to the present invention will be described below.

A plain filter shown in Table 1, a double concentric filter having no core wound as shown in Table 2, and a double concentric filter wound with a core shown in Table 3 were experimentally produced. Here, the plain filter is a filter as a comparative example including a single core element. Further, a double concentric filter in which the core portion is not wound (core non-wrapping) is a filter having a double concentric structure as a comparative example manufactured using different tows for the core portion and the sheath portion. It is not wrapped. The filter of the double concentric structure in which the core portion is wound (core wrap) is a filter according to the present invention, and also includes filters D and E as comparative examples. Cellulose acetate was used as a fiber material for these core elements.

These filters were connected to tobacco rods using chip paper to prepare sample rolls. Properties other than the filter and the tipping paper conformed to the standard of ordinary cigarettes.

That is, cigarette blending is used for the chopping, and the cigarette rod wrapping paper has an air permeability of 60 mL.
/ Cm ² · minute · 100 mmH ₂ O. The winding size was a tobacco rod length of 59 mm, a filter length of 25 mm, and a winding circumference of 24.8 mm. In the tip paper, the ventilation hole opening position is 12.5, 1
9, 22 mm, 30 mm width, two or four rows of ventilation holes drilled by laser, with air permeability of 800, 1200, 1600,
The material used was 2400 mL / cm ² · minute · 100 mmH ₂ O.

These sample windings were conditioned at a temperature of 22 ° C. and a relative humidity of 60% for 48 hours or more, and then averaged weight ± 10 mg and average product air resistance ± using a winding quality measuring instrument.
Those having 5 mmH ₂ O and an average Vf ± 2% were selected and subjected to an experiment.

With respect to the sample windings 1 to 10 as described above, the delivery amount of nicotine, tar, and CO gas and the number of puffs were measured under standard smoking conditions using an eight-smoker manufactured by Filtrona. Also, from the measured values obtained, CO 2
/ Tar ratio was determined.

Table 4 shows the results of a sample winding as a comparative example using a plain filter, and Table 5 shows the results of a sample winding as a comparative example using a core non-wrap double concentric filter.
Table 6 shows the results of sample winding using the core-wrap double concentric filter. In Table 6, lot 3 is a comparative example, and lots 6, 7, 8, 9, and 10 are cigarettes of the present invention. Incidentally, CO / tar ratio tobacco rod are commonly used in all samples winding 10 is 0.63, the ventilation resistance of the tobacco rod was 51mmH ₂ O.

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

[Table 3]

[0041]

[Table 4]

[0042]

[Table 5]

[0043]

[Table 6]

As is clear from Tables 4 and 5, when a plain filter or a core non-wrap double concentric filter was used, the CO / tar ratio was 0.97, and the CO / tar ratio was 0.9.
70, which did not satisfy the conditions of the present invention.

As is apparent from Table 6, when the core-wrapped double concentric filter is used, the core diameter is 3.5 mm, the core / sheath PD ratio is 0.50, and the ventilation hole opening position is 12.5 mm. Sample winding lot 3 as a comparative example has a product airflow resistance of 82 and a CO / tar ratio of 0.6.
6, which did not satisfy the conditions of the present invention. Lots 4 and 5 having a core diameter of 3.5 mm, a core / sheath PD ratio of 2 and 1, and a ventilation hole opening position of 22 mm.
Also, although the product ventilation resistance increased, the CO / tar ratio was 0.1%.
72, 0.68, which did not satisfy the conditions of the present invention.

On the other hand, lots 6 and 7 having a core diameter of 3.5 mm, a core / sheath PD ratio of 0.5 and 0.25, and a vent hole opening position of 22 mm have product airflow resistances respectively. The ratios of 94/100 and CO / tar were 0.47 and 0.36, respectively, which satisfied the conditions of the present invention.
Lot 8 in which only the ventilation hole opening position was changed to 19 mm from Lot 7 also satisfied the conditions of the present invention.

Lots 9 and 10 having a core diameter of 5.5 mm, a core / sheath PD ratio of 0.25 and 0.5, and a vent hole opening position of 22 mm have product airflow resistances of 117 and 100, respectively. , CO / tar ratios were 0.58 and 0.52, respectively, which satisfied the conditions of the present invention.

On the other hand, Table 6 also shows whether or not smoke has passed through the sheath. This is the result of observing whether or not smoke has passed through the sheath portion of the double concentric filter after the filter was cut in the axial direction after smoking the sample winding. When smoke does not pass through the sheath portion, it indicates that part of the air that has flowed in from the ventilation hole flows backward and all the smoke flows into the core portion. In Table 6, in each of the lots 6, 7, 8, 9, and 10 satisfying the conditions of the present invention, smoke did not pass through the sheath portion, and a part of the air flowing in from the ventilation holes flowed backward, so that all the lots did not. Smoke flows into the core.

From the above results, the core / sheath PD ratio is 1
Hereinafter, that is, the ventilation resistance coefficient of the core portion is smaller than the ventilation resistance coefficient of the sheath portion, and the vent hole opening position is 19 mm or more, that is, the position where the ventilation hole is separated by about 70% or more of the length from the suction end of the filter. In this case, part of the air that has flowed in from the ventilation holes flows backward, allowing all the smoke to flow into the core part with a low filtration rate, exhibiting the function as a low filtration filter, and satisfying the target conditions. Was.

[0050]

As described above, in the cigarette with a filter of the double concentric structure according to the present invention, the core portion is wound with an air-impermeable film, and the core has a ventilation resistance coefficient of the sheath portion. It is less than 0.8 times the resistance coefficient, and the ventilation hole has a length of about 7
Because it is located at a distance of 0% or more, part of the air that has flowed in from the ventilation holes flows backward and all the smoke flows into the core part having a low filtration rate, thereby exhibiting the function as a low-filtration filter. to the ratio of 0.6 or less, and, to the product air-permeation resistance in the range of 90~130mmH ₂ O, generally can be achieved incompatible requests at the same time as.

[Brief description of the drawings]

FIG. 1 is a partially exploded perspective view showing a cigarette provided with a filter having a double concentric structure according to the present invention.

FIG. 2 is a sectional view of the filter plug of the cigarette shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Tobacco rod 11 ... Tobacco cut 12 ... Circular paper 20 ... Filter plug 211 ... Filter core part 212 ... Air impermeable film 213 ... Filter sheath part 30 ... Tip paper 301 ... Ventilation hole

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tsuneshi Akagi 1-17-7 Yokokawa, Sumida-ku, Tokyo F-term in Japan Tobacco Inc. 4B045 AA41 AA46 AA47 AB05 AB12 AB16 BC08 BC17 BC36 BD16

Claims (2)

[Claims] A filter plug comprising a filter core portion and a filter sheath portion disposed around the core portion and concentrically with the core portion; A tip paper that covers the downstream end of the tobacco rod and substantially the entire peripheral surface of the filter plug and connects the tobacco rod and the filter plug; and the CO / tar ratio of the tobacco rod itself is 0.65 or less. And the tobacco rod itself has a ventilation resistance of 40 mmH _2.
O or more, wherein the filter core portion is wound by an air-impermeable film, and the airflow resistance coefficient of the filter core portion is 0.1 to 0.8 times the airflow resistance coefficient of the filter sheath portion. The tip paper has an opening position at a position separated from the downstream end of the tip paper with a length of 70% or more of the entire length of the filter plug in a region corresponding to the filter plug, and has a circumferential direction. A ventilation hole row consisting of a plurality of ventilation holes formed along the line, and the air inflow rate from the tip paper is 30 to 8
Cigarette with a double concentric filter, characterized in that it is 5%. _2. A product having a product airflow resistance of 90 to 130 mmH ₂ O and a CO / tar ratio of 0.6 or less.
The cigarette described.