JP2001095552A - Filter for cigarette smoke - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To efficiently remove harmful components in mainstream tobacco smoke and reduce the amount of smoke components delivered to the oral cavity of smokers. A least CaO, B ₂ O _3, constituting a filter for tobacco smoke phase-separated glass composed of SiO ₂ and Al ₂ O ₃ in the porous glass obtained by elution with acid. The porous glass may be combined with a filter material. As the filter material, a cellulose ester (eg, cellulose acetate) can be used. When combined with a filter material, about 1 to 50 parts by weight of porous glass can be used for 100 parts by weight of the filter material. In such a cigarette filter smoke, filtration rate of nicotine for the ventilation resistance (mmH ₂ O / 20 mm) (%) of about .65 to 0.8%, tar filtration rate (%) of 0.8 to 0. It is about 9. When the porous glass is added to cellulose acetate fibers,
The removal rate of nicotine and tar can be greatly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter for tobacco smoke capable of efficiently removing harmful components in tobacco smoke, and an improvement in the removal rate of the harmful components by adding a specific porous glass to the filter material. On how to do it.

[0002]

2. Description of the Related Art In recent years, in view of the taste (taste) or physiological effects of tobacco, the inflow of smoke components (especially harmful components) into the oral cavity of smokers, mainly in developed countries, (hereinafter referred to as delivery amount). Various studies have been made to reduce the above. Above all, methods for improving the filtration efficiency of tobacco smoke filters and the like have been mainly studied.

[0003] At present, most of practically used tobacco smoke filters use a crimped fiber tow of cellulose diacetate, which reduces the single fiber fineness of the tow or increases the fiber filling amount. By doing so, the filtration efficiency of the filter is improved.

[0004] However, such a filter for cigarette smoke has a limit in the filtration efficiency that can be achieved within a practical range of airflow resistance, and, while satisfying the taste, a specific component (especially a harmful component) in the smoke component. Selectively removing only
That is, it is difficult to largely change the filtration ratio of each component in the smoke.

As a method for selectively removing specific components in smoke, it is known to add various additives (inorganic adsorbents such as zeolite and silica gel) to a filter for cigarette smoke.

Japanese Unexamined Patent Publication (Kokai) No. 63-248380 discloses a radical for cigarette smoke which can suppress the smell of activated carbon by adding zeolite and activated carbon at a predetermined ratio and efficiently remove radical components in smoke. A capture agent is disclosed. JP-A-02-308784 discloses a cigarette filter containing zeolite as an adsorbent, and describes that harmful gas phase components in smoke can be adsorbed and collected. JP-A-53-39266 discloses a method for physically and chemically adsorbing and removing CO and CO ₂ using a filter containing a natural or synthetic zeolite. In addition, Tokuhyohei 10-50763
No. 0 discloses a cigarette smoke filter containing a hydrophobic zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio greater than 5.5.

Japanese Patent Laid-Open No. 60-141276 discloses a method for manufacturing a filter for a tobacco pipe in which silica gel powder is added to a filter made of paper and having a specific structure, which can remove harmful substances and the like. Is described. JP-A-63-169980 discloses a tobacco filter to which a filler such as silica gel or activated carbon and far-infrared radiating inorganic fine particles such as zirconium oxide or cobalt oxide are added to improve the taste. It states that it can.

As described above, when zeolite, silica gel or the like is contained in the filter, it is possible to some extent to remove harmful components and to improve taste.
However, zeolites and silica gel are often used
It is powdery or granular, has a small degree of freedom in shape, and the form of addition to the filter is limited.

Generally, the adsorption function itself as a filter for cigarette smoke is made of a material (filter material and additives).
It depends largely on characteristics other than the adsorption function,
For example, productivity (such as processability), quality stability, and filter design greatly depend on the form or shape of a material (particularly, an additive or the like). Therefore, even if the adsorption function is excellent, the degree of freedom of the form or shape is small, which may be disadvantageous in practical use and lacks versatility. For example, zeolite is crystalline and is limited to a granular form, and silica gel has a wide pore distribution, and it is difficult to control the pore diameter, and in addition, fibrous, particulate, etc. When processed into various shapes, the holes are destroyed, and the adsorbing ability is reduced. Therefore, it is difficult to process into various shapes while maintaining the pores.

[0010]

Accordingly, an object of the present invention is to significantly reduce the amount of smoke components delivered to the oral cavity by efficiently removing harmful components from tobacco smoke while maintaining taste. An object of the present invention is to provide a tobacco smoke filter.

Another object of the present invention is to provide a filter for cigarette smoke which is excellent in productivity, particularly processability, by using an additive having a large degree of freedom in form or shape.

Still another object of the present invention is to provide a method for improving the removal rate of harmful components.

[0013]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, when a filter for cigarette smoke is made of a specific porous glass, removal of harmful components is maintained while maintaining taste. The present inventors have found that it is possible to improve the yield, improve the processability, add in various forms, and improve the productivity of the filter for tobacco smoke, and completed the present invention.

That is, the tobacco smoke filter of the present invention comprises at least CaO, B ₂ O ₃ , SiO ₂ and Al ₂ O ₃
Is included. The porous glass may be combined with a filter material to form a tobacco smoke filter. As the filter material, cellulose ester (eg, cellulose acetate)
Etc. can be used. When combined with a filter material, about 1 to 50 parts by weight of porous glass can be used for 100 parts by weight of the filter material. In the cigarette smoke filter, the ventilation resistance (mmH ₂ O / 20 m
The ratio of the filtration rate (%) of nicotine to m) is 0.65
About 0.8, the rate of tar filtration (%) is 0.8 ~
It is about 0.9.

[0015] The present invention also includes a method for improving the removal rate of harmful components (particularly, nicotine and tar) by adding the porous glass to cellulose acetate fibers.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION [Porous Glass] Porous glass is composed of at least CaO, B ₂ O ₃ , SiO ₂ and Al ₂ O _3.
Is not particularly limited as long as the glass has a porous structure, and various kinds of porous glasses can be used. Further, the porous glass may contain Na ₂ O, MgO or the like in addition to the above four components.

Examples of such a porous glass include, for example, Japanese Patent Publication No. 62-25618 and Japanese Patent Publication No.
Disclosed in 66777 JP by which CaO-B ₂ O ₃ -S
such iO ₂ -Al ₂ O ₃ based porous glass can be used.
The porous _{glass, CaO-B 2 O 3 -SiO} 2 -Al 2
The phase-separated glass is formed by elution with an acid, for example, by dissolving and removing one of the two separated phases with an acid, utilizing the easy phase separation property of the O ₃ glass.

More specifically, the porous glass is made of, for example, (1) volcanic glass (eg, shirasu) contained in volcanic ash or the like, boric acid, lime, or the like as raw materials, and (2) a glass ( Base glass), and heat the base glass above the glass transition temperature to cause phase separation,
(3) It can be obtained by performing acid treatment and at least partially dissolving and removing metal oxides such as aluminum, iron, alkali metal and alkaline earth metal.

The production of porous glass by such a method is advantageous because volcanic glass (eg, shirasu) contained in volcanic ash can be used as a raw material, and the vitrification rate can be improved and the cost can be reduced. In addition,
Shirasu is a proper noun for siliceous ash deposits widely distributed in southern Kyushu.

The pore diameter of the porous glass is not particularly limited, and is, for example, 1 nm to 10 μm, preferably 1 nm to 1 μm.
μm, and more preferably about 1 to 50 nm.

The pore volume of the porous glass is usually 0.4
About 0.6 cm ³ / g. The specific surface area of the porous glass is 0.1 to ²⁰⁰ m ² / g, preferably 0.1 to ²⁰⁰ m ² / g.
It is about 5 to 50 m ² / g, more preferably about 1 to 10 m ² / g.

The porous glass is amorphous, and the pore size can be controlled relatively uniformly. The pore size is
It can also be adjusted by adjusting the ratio of each component (particularly the ratio of the soluble component to the acid), the form and degree of phase separation, and the degree of elution of the soluble component by the acid. In addition, as described in JP-B-63-66777, when the porous glass contains Na ₂ O in addition to CaO, B ₂ O ₃ , SiO ₂ and Al ₂ O ₃ , the control of the pore size is difficult. It is relatively easy. In addition, because it is rich in processability, it is processed into a predetermined form or shape and eluted with acid, or after elution, is further pulverized to maintain the pores without impairing the adsorption capacity for harmful components Can be processed into various shapes (fibrous, granular, etc.). Therefore, in a desired form or shape, the porous glass can be used alone, or can be combined with other filter materials and the like, which is advantageous in terms of filter design and further enhances productivity (workability, etc.). It is also possible to improve properties such as quality stability.

In the fibrous porous glass, the fiber diameter is
For example, it is about 1 to 100 μm, preferably about 5 to 50 μm, and the average particle size of the granular porous glass is, for example, 1 to 1000 μm, preferably 5 to 500 μm, more preferably 10 to 300 μm (for example, 10 to 10 μm).
0 μm).

As long as the porous glass is contained in the tobacco smoke filter, the mode of the porous glass is not particularly limited, and the fibrous porous glass may be directly formed into the filter, The filter may be formed in combination with another filter material. When combined with another material, the state of distribution of the porous glass is not particularly limited, and the porous glass may be uniformly distributed (scattered) throughout, or may be non-uniformly or partially present. The porous glass can be added to a general tobacco smoke filter in various modes or forms (fibrous, particulate, pulverized, etc.) depending on the structure. [Filter Material] When a filter for tobacco smoke is constituted by combining the porous glass and the filter material, the filter material is, for example, cellulose (eg, wood pulp or linter pulp which may be fibrillated), regenerated cellulose ( Viscose rayon, cuprammonium rayon, etc.), cellulose ester, synthetic polymer (polyester, polyurethane, polyamide, polyethylene, polypropylene, etc.), etc., and the filter material can be in the form of fiber, sheet or paper (sheet having a papermaking structure). Etc.).

Preferred filter materials include cellulose fibers and / or cellulose ester fibers, and often contain at least cellulose ester fibers for improving the taste. Examples of the cellulose ester fibers include organic acid esters such as cellulose acetate, cellulose propionate, and cellulose butyrate (for example, esters with an organic acid having about 2 to 4 carbon atoms); cellulose acetate propionate, and cellulose acetate butyrate. And mixed acid esters such as cellulose esters; and cellulose ester derivatives such as polycaprolactone-grafted cellulose esters. These cellulose ester fibers can be used alone or in combination of two or more.

The average degree of polymerization (viscosity average degree of polymerization) of the cellulose ester is, for example, 50 to 900, preferably 20 to 900.
The average degree of substitution of the cellulose ester can be selected, for example, from a range of about 1.5 to 3.0.

A preferred cellulose ester is cellulose acetate.

The cross-sectional shape of the fiber is not particularly limited, and is, for example, circular, elliptical, irregular (for example, Y-shaped, X-shaped, I-shaped).
Shape, a C shape, an H shape, etc.) or a hollow shape. The fiber diameter and the fiber length can be selected according to the type of the fiber. For example, the fiber diameter is 0.01 to 100 μm, preferably about 0.1 to 50 μm, and the fiber length is 50 μm to 5 c.
m, preferably in the range of about 100 μm to 3 cm. The fineness of the cellulose ester is 1 to 1
It can be selected from a range of about 6 denier, preferably about 1 to 10 denier. Fibers such as cellulose ester fibers
Either non-crimped fiber or crimped fiber may be used.

The fibers can be used, for example, in the form of a tow (fiber bundle) formed by bundling 3,000 to 100,000, preferably about 5,000 to 50,000, cellulose ester fiber single fibers (filaments).

When a filter for tobacco smoke is constituted by combining porous glass and a filter material, the ratio of the porous glass can be appropriately selected from a wide range according to a desired delivery amount. 1 to 50 parts by weight, preferably 5 to 40 parts by weight (for example, 10 to 40 parts by weight), more preferably 1 to 50 parts by weight with respect to parts by weight.
It is about 0 to 30 parts by weight. When the ratio of the porous glass is less than 1 part by weight, the effect of removing harmful components in the mainstream tobacco smoke is small, and when it exceeds 50 parts by weight, depending on the shape of the porous glass, the ventilation resistance increases or the taste changes. There is a fear.

The filter for cigarette smoke and the filter material may contain a binder component for causing the filter rod to have an appropriate hardness. As the binder component, a plasticizer (such as triacetin), a resin (such as a water-soluble polymer or a water-insoluble polymer), or a polysaccharide such as starch or a starch derivative can be used depending on the type of the filter material.

Further, tobacco smoke filters and filter materials are made of various additives, for example, whiteness improving agents (for example, titanium oxide, preferably anatase type titanium oxide), kaolin, talc, diatomaceous earth, quartz, calcium carbonate. Inorganic fine powders such as sodium, barium sulfate and alumina; heat stabilizers such as salts of alkali metals and alkaline earth metals;
Coloring agents; flavoring agents (such as fragrances); oil agents;
Sorbents (activated carbon,
Silica gel, alumina, zeolite, silica, silica
Porous materials such as alumina and nickel-alumina);
Biodegradation promoter; may contain a photodegradation promoter and the like.

The filter for tobacco smoke is formed by molding porous glass fiber into a filter shape or, if necessary, by combining a fibrous porous glass and a granular porous glass using a binder resin or the like. It can be manufactured by molding.

A filter for cigarette smoke composed of porous glass and a filter material can be manufactured by a conventional method according to the form of the filter.

For example, a filter made of porous glass may be sandwiched between filters (filter chips) made of a filter material, or a filter may be formed between filters (filter chips) made of a filter material.
If necessary, a fibrous or granular porous glass may be filled with a binder resin to be used as a dual filter or a triple filter. It can also be produced by winding a filter material into a rod shape with wrapping paper while adding a porous glass together with a binder component as necessary. In the production of the filter, the addition of the granular porous glass can use the activated carbon addition apparatus used in the production of the tobacco smoke filter as it is. For example, when fibers are used as a filter material, a fiber bundle (tow) is spread to a spread width of about 5 to 50 cm, and a porous paper or a binder component is added as necessary, and the fiber bundle (tow) is wound up in a rod shape with a wrapping paper. Can be manufactured. In addition, a filter can be obtained by adding porous glass or a binder component to the filter material, forming the sheet into a paper-like sheet by a method such as paper making, and then winding the sheet into a rod shape with a wrapping paper. Can be. The wound rod-shaped filter is usually cut into a predetermined length to form a filter tip in many cases.

The tobacco smoke filter thus obtained has a ventilation resistance that does not impair the filter characteristics. For example, the length is 20 mm and the diameter is 24.5 mm.
For a filter of φ, the ventilation resistance is 30-70 mmH
₂ O / 20 mm (mm WG / 20 mm: water gauge), preferably 40 to 65 mm WG / 20 mm, more preferably about 45 to 60 mm WG / 20 mm in many cases.

Since the filter for cigarette smoke of the present invention contains at least the porous glass, the components in the cigarette smoke,
For example, nicotine, tar, volatile components [alcohol (such as methanol), aldehyde (acetaldehyde,
Harmful components such as acrolein), ketones (acetone, etc.), unsaturated hydrocarbons (isoprene, etc.) etc. can be efficiently removed, and the filtration efficiency for these smoke components is high, and the smoke components in the oral cavity of smokers The amount of delivery can be significantly reduced. The taste can also be adjusted by the pore diameter and pore volume of the porous glass, the amount of the porous glass, the combination with the filter material, and the like.

The tobacco smoke filter of the present invention exhibits a high removal rate (filtration rate) for tobacco smoke components. Volatile components in tobacco smoke include, for example, a ventilation resistance of 60 mmH ₂ O.
Assuming that the peak intensity of the gas chromatograph after passing through a / 20 mm cellulose diacetate filter is 1, the peak intensity after passing through the tobacco smoke filter of the present invention is, for example, 0.6 to 0.9, preferably 0 to 0.9. 0.7-0.
It is about 9.

Further, the tobacco smoke filter of the present invention comprises:
The smoke component (particularly, nicotine and tar) can be efficiently removed without increasing the ventilation resistance. This is represented by the ratio (filtration efficiency) of the filtration rate (%) of nicotine (or tar) to the ventilation resistance (mmH ₂ O / 20 mm),
For example, when the airflow resistance of 50~60mmH ₂ O / 20mm, nicotine filtration rate / air flow resistance = 0.65 to 0.
8, preferably about 0.75 to 0.8, and the filtration rate of tar / ventilation resistance = 0.8 to 0.9, preferably 0.8
It is about 5 to 0.9. The filtration rate of nicotine is, for example, about 30 to 50%, preferably about 35 to 45%, and the filtration rate of tar is, for example, about 40 to 60%, preferably about 40 to 50%.

As described above, according to the present invention, by including the porous glass in the tobacco smoke filter,
The removal rate of harmful components (particularly, nicotine, tar, etc.), in particular, the ratio of the filtration rate to the ventilation resistance can be improved. Also,
If the porous glass is added to an existing filter made of cellulose acetate fiber or the like, the removal rate of the harmful component can be significantly improved.

[0041]

According to the present invention, since the filter for tobacco smoke is constituted by at least a specific porous glass, it is possible to efficiently remove harmful components in the mainstream tobacco smoke while maintaining the taste, and to improve the oral cavity of the smoker. The amount of smoke component delivered to the inside can be significantly reduced. In addition, since the porous glass is rich in processability, the productivity of the filter for cigarette smoke can be improved.

[0042]

The present invention will be described below in more detail with reference to Examples, but the present invention is not limited to these Examples.

The measurement of the ventilation resistance, the nicotine and tar filtration rates, and the evaluation of the filtering properties of the volatile components of the tobacco smoke filter samples in Examples and Comparative Examples were carried out by the following methods. All of the following measurements were performed after the produced sample tobacco was left in an atmosphere at a temperature of 23 ° C. and a relative humidity of 65% for 24 hours or more. (1) Airflow resistance The pressure loss (mmWG) when the flow rate of air passing through the tobacco smoke filter sample was 17.5 ml / sec was measured using an automatic airflow resistance meter (manufactured by Filtrona, FTS300). (2) Filtration Rate and Filtration Efficiency of Nicotine and Tar A tobacco smoke filter sample was connected to a leaf tobacco part of a commercial tobacco (Peacelight, manufactured by Japan Tobacco Inc.) to produce a sample tobacco. The obtained sample tobacco was used at a flow rate of 17. using a piston-type constant volume automatic smoker (RM20 / CS, manufactured by Borgwald).
Smoking was performed under the conditions of 5 ml / second, smoking time of 2 seconds / time, and smoking frequency of 1 time / minute.

Nicotine and tar in the smoke passed through the tobacco smoke filter were collected by a glass fiber filter (Cambridge filter). The amount of nicotine was calculated by a gas chromatograph (G-3000, manufactured by Hitachi, Ltd.), and the amount of tar was calculated by a gravimetric method. The amounts of nicotine and tar adhering to the tobacco smoke filter were calculated in the same manner. The amounts of nicotine and tar attached to the tobacco smoke filter were defined as Tn and Tt, respectively, and the amounts of nicotine and tar attached to the Cambridge filter were defined as Cn and Ct, respectively.

Nicotine filtration rate (%) = 100 × Tn / (Tn + Cn) Tar filtration rate (%) = 100 × Tt / (Tt + Ct) The filtering efficiency of the tobacco smoke filter is as follows. The value obtained by dividing the filtration rate (%) of nicotine and tar by the airflow resistance (mmWG) was calculated as the filter characteristic. For each sample, it was determined that the larger the value of the filtration efficiency, the better the filter characteristics. (3) Evaluation of Filterability of Volatile Components Tobacco smoke filter samples were connected to commercially available tobacco (Peacelight, manufactured by Japan Tobacco Inc.) to produce a tobacco sample. The obtained sample tobacco was used at a flow rate of 17. using a piston-type constant volume automatic smoker (RM20 / CS, manufactured by Borgwald).
Smoking was performed under the conditions of 5 ml / second, smoking time of 2 seconds / time, and smoking frequency of 1 time / minute. At this time, a gas sampler was connected in the middle of the smoking line, a certain amount of the smoke component of the fifth puff was directly introduced into the gas chromatograph, and the peak intensity of each component was measured. The peak intensity ratio was calculated with the peak intensity as 1.

Example 1 Porous glass fiber having a fiber diameter of 6-30 μm (PG fiber grade L, manufactured by Oat Tire Co., Ltd., pore volume 0.28 cc /
g, pore surface area: 3.03 m ² / g, pore diameter: 4 nm) was pulverized with a coffee mill to obtain a porous glass powder having a length of about 30 μm. A tow of cellulose diacetate fiber composed of 3.0 denier filaments having a Y-shaped cross section (total denier: 36000) was applied to a tobacco smoke filter manufacturing hoist (manufactured by Hauni Co., Ltd., AF2 / FR4). The fiber is opened to 25 cm, the crushed PG fiber is sprayed on the tow, the tow is supplied to a wrapping device, the tow is wound up at 400 m / min using a wrapping paper, and the obtained filter rod is 120 mm in length. Cut into pieces. Further, the filter rod was cut into a length of 20 mm using a cutter to obtain a filter sample for tobacco smoke. The content of PG fiber in the filter sample is 20% by weight of the whole filter.
Met.

With respect to the obtained filter sample, the air permeability and the filtration rate of harmful components were measured by the above-mentioned method, and the filter characteristics were evaluated.

Example 2 A filter sample of cellulose diacetate having a length of 20 mm was prepared in the same manner as in Example 1 except that the PG fiber pulverized product was not sprayed, and this sample was further reduced to a half length (10 mm). After cutting, the same crushed PG fiber product as in Example 1 was inserted between the two filter samples and fixed with wrapping paper to obtain a filter sample for tobacco smoke.
The content of PG fiber in the whole filter is 20% by weight
Met. The filter characteristics of the obtained filter sample were evaluated in the same manner as in Example 1.

Example 3 Instead of the PG fiber pulverized product, the P before pulverization used in Example 1 was used.
A sample was prepared in the same manner as in Example 2 except that the G fiber was used, and the filter characteristics were evaluated.

Example 4 A sample was prepared in the same manner as in Example 1 except that a porous glass granulated product (manufactured by Oats Tire Co., Ltd., PG granulated product, passed through a 300 μm mesh) was used instead of the PG fiber crushed product. And the filter characteristics were evaluated.

Comparative Example 1 A PG fiber pulverized product was not sprayed and the airflow resistance was 50 mm WG /
Except for adjusting the stuffing amount to be 20mm long,
A filter sample of cellulose diacetate having a length of 20 mm was prepared in the same manner as in Example 1, and the filter characteristics were evaluated.

Comparative Example 2 A filter sample was prepared in the same manner as in Comparative Example 1 except that the amount of packing was adjusted so that the airflow resistance became 56 mmWG / 20 mm length, and the filter characteristics were evaluated.

Comparative Example 3 A filter sample was prepared in the same manner as in Comparative Example 1 except that the amount of packing was adjusted so that the airflow resistance became 60 mmWG / 20 mm length, and the filter characteristics were evaluated.

The results of Examples and Comparative Examples are shown in Tables 1 and 2.

[0055]

[Table 1]

[0056]

[Table 2]

As is clear from Table 1, in the filter samples of the examples, the filtration efficiency of nicotine and tar is greatly improved as compared with the comparative example. Further, as is clear from Table 2, in Examples, all volatile components have higher filterability than Comparative Example 3.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Satoshi Furusawa 9-1, Kawaramachi, Izumiotsu-shi, Osaka F-term in Otsu Tire Co., Ltd. 4B045 AA45 AB17 BA03 BA08 BC02 BC08 BC12

Claims (7)

[Claims] 1. A tobacco smoke filter comprising a porous glass comprising at least CaO, B ₂ O ₃ , SiO ₂ and Al ₂ O ₃ . 2. The tobacco smoke filter according to claim 1, further comprising a filter material. 3. The filter for cigarette smoke according to claim 2, wherein the filter material is a cellulose ester. 4. A filter for cigarette smoke according to claim 2, wherein the filter material is cellulose acetate. 5. A filter material for 100 parts by weight,
The cigarette smoke filter according to claim 2, comprising 1 to 50 parts by weight of the porous glass. 6. The ratio of the filtration rate (%) of nicotine to the ventilation resistance (mmH ₂ O / 20 mm) is 0.65 to 0.5.
8. The filter for cigarette smoke according to claim 1 or 2, wherein the ratio of the filtration rate (%) of tar is 0.8 to 0.9. 7. A method for improving the removal rate of nicotine and tar by adding the porous glass according to claim 1 to cellulose acetate fiber.