WO2007117115A1

WO2007117115A1 - Cigarette filter using bamboo activated carbon

Info

Publication number: WO2007117115A1
Application number: PCT/KR2007/001740
Authority: WO
Inventors: Chung-Ryul Kim; Haeng-Hyun Jang; Young-Hoi Kim; Moon-Soo Rhee
Original assignee: Kt & G Corporation
Priority date: 2006-04-11
Filing date: 2007-04-10
Publication date: 2007-10-18
Also published as: CN101420875A; JP2009533051A; KR100636083B1

Abstract

The present invention relates to a cigarette filter using bamboo activated carbon, which has excellent effect of removing harmful components as compared to conventionally used oak charcoal or bamboo charcoal. The functional cigarette filter according to the invention can give aesthetic comfort at the time of smoking due to the flavor of bamboo. More specifically, the invention relates to a cigarette filter using bamboo activated carbon, which comprises fibrous material consisting of cellulose acetate and at least one filtering material charged with bamboo activated carbon. The cigarette filter according to the present invention has excellent ability to adsorb harmful substances and at least three-folds of ability to adsorb iodine, as compared to a cigarette filter using conventionally used charcoal or coconut shell activated carbon.

Description

CIGARETTE FILTER USING BAMBOO ACTIVATED CARBON

[Technical Field] The present invention relates to a cigarette filter which gives aesthetic comfort at the time of smoking due to bamboo flavor, and has excellent ability to adsorb nicotine, tar and volatile harmful substances due to bamboo activated carbon.

[Background Art]

In general, a cigarette consists of cut tobacco and a cigarette filter. Since particular substances such as nicotine and tar as well as toxic substances such as volatile organics contained in the smoke puffed from cigarette filter at the time of smoking are harmful to human body, cigarette products are developed by reducing the harmful components such as nicotine and tar generated from burning, and thus reducing the amount of being inhaled in human body by charging an adsorbent such as charcoals including oak fine charcoal or the like in a double or triple structure of the filter. However, conventional charcoal has small specific surface area of 100-300 mVg, or though having a large specific surface area, it has insufficient ability to adsorb organic substances which are harmful to human body, to give insufficient filtering efficiency. Thus, development of material having larger specific surface are and better flavor to give psychological comfort, as well as having very excellent ability to remove harmful material with similar specific surface area.

Bamboo is a monocotyledonous woody plant belonging to Gramineae family, originated from subtropical Asia. In Korea, there are 11 species of bamboo growing wild, including Phyllostachys bambusoides, black bamboo, Phyllostachys pubescen Mazel and Sasa borealis. Bamboo has very strong viability and rapidly spreads with subterranean stems, so that other plants cannot survive in a bamboo field. Bamboo does not bloom for several decades, and when it blooms, all plants in the field wither at once. When bamboo shoots spring up in spring, enormous accumulated energy works to grow up the length by up to 1 m one day. Growth of bamboo in diameter is completed within 4 weeks, and then bamboo hardens for 3-5 years until the harvest.

Bamboo charcoal has higher utility value due to its property of rapid growth as compared to other kinds of charcoal. As wood is carbonized, only cellulose remains on cell walls, thereby charcoal has many pores. Particularly, bamboo charcoal has more pores because of larger cell size and wider cell intervals. Internal surface area of 1 g of bamboo charcoal is about 100-300 m², to provide excellent water sustenance, breathability, adsorbability and heat accumulation, but the bamboo charcoal does not have high efficiency of absorbing harmful substances such as nicotine and tar when applied to a cigarette filter. Thus, investigations are required to enhance the specific surface area and provide excellent adsorbability .

[Disclosure] [Technical Problem]

In order to overcome such disadvantages, the inventor has studied on substances having better adsorbing ability than common charcoal. As the result, he found that bamboo activated carbon has increased specific surface area and enhanced ability to adsorb harmful substances, and noticeable effect of adsorbing organic substances due to other than the effect of specific surface area, while providing bamboo flavor, and completed the present invention.

The object of the present invention is to provide a cigarette filter which gives aesthetic comfort due to bamboo flavor, and has enhanced ability to filtering nicotine, tar and harmful organics at the time of smoking. More specifically, the object of the invention is to provide a cigarette filter having excellent ability to adsorb harmful substances and iodine as compared to conventional cigarette filters using various activated carbons such as common charcoal or coconut shell activated carbon. In addition, the present invention intends to provide a cigarette filter consisting of filtering material using bamboo activated carbon and fibrous layer (s), and to provide a cigarette filter which can effectively filter harmful substances with varying constructions of said filtering material and fibrous layer.

[Technical Solution]

The present invention relates to a functional cigarette filter using bamboo activated carbon having excellent effect of removing harmful components as compared to conventionally used oak charcoal or bamboo charcoal, which can give aesthetic comfort at the time of smoking due to the flavor of bamboo.

More specifically, the present invention relates to a cigarette filter consisting of fibrous material and filtering material, which comprises at least one filtering material charged with bamboo activated carbon. For instance, the filtering material charged with bamboo activated carbon may be located between individual fibrous materials, or said bamboo activated carbon may be distributed throughout the fibrous material depending on the varying applications.

According to the present invention, bamboo is carbonized with heat treatment by baking at 800-1300 "C to form bamboo char, which is then activated by adding steam having 1.5~3-folds by weight of bamboo char to prepare said bamboo activated carbon. Other than steam, CO₂ or chemicals such as phosphoric acid, ZnCl₂ and KOH may be used. Bamboo char is produced after the

step of baking at 800~1300^°C; and when steam is added thereto at 600~950^°C, carbon is activated to increase the specific surface area by at least 3 times to give bamboo activated carbon. The inventor found that bamboo activated carbon obtained as described above showed noticeably enhanced ability to adsorb harmful components as compared to bamboo char or other activated carbon having similar specific surface area, and by using such bamboo activated carbon, a novel cigarette which gives flavor of bamboo, as if bamboo fluid is inhaled, at the time of smoking to provide psychological comfort, while removing characteristic odor of cigarette, can be obtained, and completed the invention.

Specific surface area of bamboo activated carbon used according to the present invention is 600-3000 m²/g, which is larger than that of conventionally used char. Further, the bamboo activated carbon has lower bulk density per identical specific surface than activated carbons originated from trees other than bamboo, with more excellent ability to remove nicotine, tar and harmful organics. The bamboo activated carbon according to the present invention has more excellent effect to adsorb harmful substances with noticeably enhanced effect of adsorbing iodine as compared to common char or coconut activated carbon. According to the invention, said bamboo activated carbon is preferably used as fine powder after pulverization. The size can be properly selected as necessary without particular restriction. When it is prepared in a triple filter, so that bamboo activated carbon between the fibrous materials is used as a filtering material, the size is preferably 16 x 35 mesh; a filter having the size smaller than this is undesirable because of high pressure drop. When a double filter consisting of a fibrous material and a filtering material is used, the size of 30 x 80 mesh is preferable in terms of workability and efficiency, 40 x 60 mesh being more preferable.

Figs. 1 to 3 show examples using the cigarette filter according to the present invention.

As shown in Fig. 1, it is possible that said pulverized particles of bamboo activated carbon are mixed with the fibrous material to be distributed therein homogeneously. As shown in Fig. 2, the filtering material can be charged so that the bamboo activated carbon filtering material is laminated between the fibrous materials. As shown in Fig. 3, it is possible that bamboo activated carbon filtering material is charged on the top of cut tobacco, and fibrous material is charged thereon. Besides, bamboo activated carbon is applicable in various forms in conventional structure of cigarette filter.

The fibrous material preferably is cellulose acetate which is conventionally employed for preparation of cigarettes, but it is not restrictive since it may be altered by a person having ordinary skill in the art as needed.

[Description of Drawings] Fig. 1 shows one example of the cigarette filter according to the present invention.

Fig. 2 shows another example of the cigarette filter according to the present invention.

Fig. 3 shows still another example of the cigarette filter according to the present invention.

Fig. 4 shows a cigarette used in the Examples of the invention.

- Description of the symbols in drawings - 1 : cut tobacco 2 : cellulose acetate fibrous material

3 : cavity to be charged with filtering materials

4 : particles of bamboo activated carbon

5 : ventlation

Other and further objects, features and advantages of the invention will appear more fully from the following description.

[Best Mode] Examples

Examples are described for more specific explanation of the present invention, but the invention is not limited to those Examples. First, in order to determine the ability of bamboo activated carbon to remove the tobacco smoke components, particularly harmful smoke components well known as Hoffmann components, physical properties of oak char, bamboo char and coconut shell activated carbon were measured and comparatively analyzed.

[Example]

Preparation of bamboo activated carbon

Bamboo was cut into 1 cm x 2 cm pieces, which was then

baked at about 1000 ^°C for 5 hours to obtain bamboo char. The bamboo char thus prepared was activated at 850 ^°C for 3 hours with incorporating 1.5- folds by weight of steam based on the weight of bamboo char. The bamboo activated carbon thus obtained was pulverized by using a pulverizer, and the particles having the particle size of 40 x 60 mesh were isolated and used for the experiments .

By using ASAP2020 Instrument from Micrometrics (U.S.A.), analyzed were specific surface area (BET, N₂) , pore distribution and pore volume. The bulk density was measured according to KSM 1802 method. The results are summarized in Table 1 .

Analysis of tobacco smoke and Results

For the analysis of ability to remove smoke components, As shown in Fig. 4, cigarette filter having triple structure in which the intermediate layer has cavity and both sides are made of cellulose acetate fiber were prepared, and the cigarette products having certain weight and pressure drop were selected. The filter prepared had 24.2 mm of circumference, 24 mm of filter length (cellulose acetate fibrous material portion 9 mm + cavity 6 mm + cellulose acetate fibrous material portion 9 mm) . Condition of selection

(of triple cavity cigarette) was 786+10 mg of weight and 89±2

TiUnH₂O of suction resistance. The cavity portion in the intermediate layer of each product cigarette selected under these conditions was incised in 5 mm x 5 mm size by using a knife, and each cavity in the intermediate layer was filled with 80 mg of exactly weighed bamboo activated carbon, and the incision was closed by using cellophane tape.

For the analysis of tobacco smoke, the experiment was performed after conditioning the sample under constant temperature and moisture (temperature 22±2^°C, relative humidity 60+5%) for 48 hours set under CORESTA condition. According to ISO 3308 to analyze the ability to adsorb organic substances including tar and nicotine as total tobacco particular substance in tobacco smoke, 20 cigarettes were individually burned by using RM20 smoking device (Heinr Borgwaldt, Germany) , and the smoke captured on 92 mm Cambridge filter pad was analyzed.

Nicotine analysis in the smoke condensate was performed by GC analysis according to ISO 10315.

Volatile substances (organics) in the main stream smoke of cigarette were determined according to the Arista experimental method (1999) .

Ability to adsorb iodine, which is an important factor to determine ability to adsorb harmful components of cigarettes, was analyzed according to the experimental procedure of KS M 1802. Analysis of ability to remove the smoke components was performed and the results are shown in Table 2.

[Comparative Example 1]

Oak fine charcoal that had been baked at about 1000 ^°C for 5 hours was pulverized by using a pulverizer, and the particles having the particle size of 40 x 60 mesh were isolated. By using ASAP2020 instrument from Micrometrics

(U.S.A.), analyzed were specific surface area (BET, N₂), pore distribution and pore volume, and the result are shown in Table 1. For the analysis of cigarette smoke, experiments were performed under same condition but using the oak charcoal instead of bamboo activated carbon used in Example 1.

Analysis of ability to remove the smoke components was performed and the results are shown in Table 2.

[Comparative Example 2]

Bamboo charcoal that had been baked at about 1000^°C for 5 hours was pulverized by using a pulverizer, and the particles having the particle size of 40 x 60 mesh were isolated. By using ASAP2020 instrument from Micrometrics (U.S.A.), analyzed were specific surface area (BET, N₂) , pore distribution and pore volume, and the results are shown in Table 1.

For the analysis of cigarette smoke, experiments were performed under same condition but using the bamboo charcoal instead of bamboo activated carbon used in Example 1.

[Comparative Example 3]

Coconut shell activated carbon

Coconut shell activated carbon which was prepared by baking at about 1000 ^°C for 5 hours and activating the charcoal by incorporating steam at 950 ^°C for 3 hours was used. Coconut activated carbon thus prepared was pulverized by using a pulverizer, and the particles having the particle size of 40 x 60 mesh were isolated. Specific surface area (BET, N₂) , pore distribution and pore volume were analyzed by using ASAP2020 instrument from Micrometrics (U.S.A.)/ and the bulk density was measured according to KS M 1802 method. The results are shown in Table 1.

For the analysis of cigarette smoke, the same experiments were performed but using coconut activated carbon instead of bamboo activated carbon used in Example 1. Analysis of their ability to remove smoke components was performed, and the results are shown in Table 2.

[Table 1]

As can be seen from Table 1, bamboo activated carbon has 3 -folds of specific surface area as compared to that of oak char or bamboo char. Though the bamboo activated carbon according to the present invention has similar specific surface area to that of the coconut shell activated carbon prepared according to the same procedure, the former has larger pore volume and lower bulk density than the latter.

In Table 2, tar, nicotine and organic substances are described as relative values on the basis of the measured value (100) of coconut shell activated carbon according to Comparative Example 3.

[Table 2]

As shown in Table 2, bamboo activated carbon according to the present invention, when used in a cigarette filter, exhibited excellent adsorption ability, so that smaller amount of tar, nicotine and organic substances was transferred as compared to the filter using oak char, bamboo char or coconut shell activated carbon. The amount of iodine (I₂) adsorbed was at least 3 -folds as compared to that of oak charcoal and bamboo char .

As bamboo activated carbon was compared to coconut shell activated carbon having similar specific surface area in terms of adsorption ability, the adsorption ability of the Example using bamboo activated carbon (though having less specific surface area than that of Comparative Example 3) showed 8.2% reduction of tar, 7.9% of nicotine, 47.5% of HCN, 58.8% of acrylonitrile, 51.6% of isoprene, 52.3% of benzene, 53.3% of toluene, 36% of 1, 3 -butadiene, 45.45% of pyridine, 42.51% of acrolein, 36.7% of propionaldehyde, 61.5% of crotonaldehyde , 62.8% of methyl ethyl ketone (MEK), resulting in increase of ability to adsorb organic substances by at least 30%. The amount of iodine adsorbed increased by 2.33% as compared to that of Comparative Example 3. Thus, though the bamboo activated carbon has less specific surface area than that of coconut shell activated carbon, the transfer of harmful smoke components is reduced by at least 30%.

When the bamboo activated carbon according to the present invention is applied to a cigarette filter, the ability to adsorb harmful smoke components and iodine component is noticeably enhanced as compared to a cigarette filter using conventional charcoal or other kinds of activated carbon.

When 20 smokers smoked cigarettes through the cigarette filter using bamboo activated carbon according to the invention, deep flavor of bamboo (like bamboo condensate) and smooth feeling gave them aesthetic comfort, while they felt dry feeling when they smoked the same through a filter using coconut shell activated carbon.

[industrial Applicability]

As described above, the cigarette filter according to the present invention has excellent ability to adsorb harmful components as well as iodine as compared to conventionally used charcoal or coconut shell activated carbon. In addition, due to the bamboo flavor, the cigarette can give aesthetic comfort at the time of smoking.

Claims

[CLAIMS!

[Claim l]

A cigarette filter consisting of fibrous materials and filtering materials, which comprises at least one filtering materials charged with bamboo activated carbon.

[Claim 2]

A cigarette filter using bamboo activated carbon according to claim 1, wherein said bamboo activated carbon is obtained by

baking bamboo at 1000~1300^°C, and then subjecting the char to steam treatment at 600~950^°C, CO₂ treatment or treatment with one chemical agent selected from phosphoric acid, ZnCl₂ and KOH.

[Claim 3]

A cigarette filter using bamboo activated carbon according to claim 2, wherein said bamboo activated carbon has 600-3000 m²/g of specific surface area.

[Claim 4]

A cigarette filter using bamboo activated carbon according to claim 1, wherein the filtering material charged with bamboo activated carbon is located between individual fibrous materials.

[Claim 5]

A cigarette filter using bamboo activated carbon according to claim 1, which comprises said bamboo activated carbon distributed homogeneously throughout said fibrous material.

[Claim 6] A cigarette filter using bamboo activated carbon according to claim 1, wherein said fibrous material is laminated on the top of the filtering material charged with said bamboo activated carbon to form two layers .

[Claim 7]

A cigarette having a cigarette filter according to any one of claims 1 to 6.