JPS6045918B2 - Tobacco smoke filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved tobacco smoke filter, and more particularly to a tobacco smoke filter with improved flavor and flavor that contains strongly basic finely powdered activated carbon made from vegetable raw materials. This relates to smoke filters.

In general, the smoke generated during smoking is roughly divided into a particle phase component and a vapor phase component.

Particle phase components consist of tar (including chemical components such as terpenes and phenols), alkaloids (niconicine, etc.), and vapor phase components consist of carbon monoxide, methane, acetaldehyde, isoprene, acetone, toluene, etc. These ingredients contain ingredients that are undesirable in terms of smoking hygiene. Tobacco smoke filters filter or adsorb and remove these components, and the particulate phase components are mainly filtered through filter media such as acetate fibers and nonwoven fabrics, while the vapor phase components are mainly filtered through filter media such as acetate fibers and nonwoven fabrics. It is adsorbed and removed by packed activated carbon. For example, among the tobacco products currently on the market made by Japan Monopoly Corporation, filters with the trade names Seven Star, Mild Seven, and Gear Pin fall under this category, and are called cigarettes with a charcoal filter. However, such cigarettes with a charcoal filter have a unique unpleasant taste called charcoal taste, which is considered to be a major drawback of the charcoal filter.

To date, various attempts have been made to improve the aforementioned unfavorable effects of activated carbon-containing cigarette filters on the smoking taste of cigarettes. Means to cause
-10740 Gin Publication), means for containing a tannic acid metal chelate compound in the activated carbon (Japanese Patent Application Laid-open No. 53-88300)
(Japanese Unexamined Patent Application Publication No. 1988-88400) and the like have been proposed. However, these technical means cannot be said to be sufficient from the viewpoint of the effect of selectively adsorbing and removing only specific undesirable components in tobacco smoke. That is, these filter-tipped cigarettes have the disadvantage that they also remove desirable flavor components during smoking. The present inventors were conducting research with the aim of developing an activated carbon filter that can efficiently remove irritating substances in tobacco smoke, such as formaldehyde, acetaldehyde, formic acid, acetic acid, hydrogen cyanide, etc. Charcoal taste is closely related to the abundance ratio of irritating substances in smoke, and surprisingly, factors such as raw materials, pore size, particle size, and basicity of activated carbon to be included in cigarette filters are selected appropriately. As a result, we succeeded in obtaining a cigarette smoke filter that suppresses the charcoal taste and improves the aroma and taste.
The present invention has now been accomplished.

That is, the present invention is made of vegetable raw materials and has a basicity of PH
9 or more, and the pore volume with a pore diameter of 20A or less is 0.10c
The present invention relates to a filter for tobacco smoke with improved flavor and flavor, which contains ultrafine powdered activated carbon with a particle size of c/d or more and 30 μm or less. Although some conventional activated carbons have relatively high surface activity, they have low basicity and have a low adsorption capacity for irritating vapor phase components such as acetaldehyde, so they have not been able to improve the problems of conventional filters. .

According to the present invention, a tobacco smoke filter is made of vegetable raw materials, has a basicity of PH9 or more, and has a pore diameter of 20A.
By incorporating ultrafine powdered activated carbon with a pore volume of 0.10 cc/q or more and an average particle size of 30 pm or less, the aroma and taste can be improved. can. The present invention will be explained in detail below. First, it is essential that the activated carbon according to the present invention be produced from vegetable raw materials.

As such vegetable raw materials, wood (preferably coniferous); South Sea plants such as coconut husk, palm husk, and coir dust; leguminous plants such as Ipir and Takakutei; wood bulbs, cotton, and linder pulp are used. Activated carbon is also manufactured from mineral materials such as pitch, coal, petroleum sludge, or synthetic materials such as polyacrylonitrile fibers and phenolic resin, but the taste of filters using these materials is as follows. It is much inferior to plant materials and is not preferred. For example, the following method can be used to produce ultrafine activated carbon powder with an average particle size of 30 pm or less using vegetable raw materials. Coniferous wood is crushed by a crusher to 200~
Grind to a particle size of 2000pm.

After that, it is heated to 500℃ from room temperature in an open hearth for 20 to (4) hours.
Carbonization treatment is carried out by raising the temperature to a temperature of 100 to 1000 pm.
A carbide with a carbon content of 70% is obtained. The carbide is subjected to activation treatment at 1200 to 1300° C. for several seconds in an air transfer type fluidized activation furnace. This activation treatment involves a high temperature that would be unimaginable for ordinary activated carbon activation treatment, and as will be described later, since the highly reactive wood-based raw material is activated in an active gas such as carbon dioxide gas or water vapor, many bases are used. It is thought that functional groups are generated on the surface of activated carbon. Although the formation mechanism is not clear, it is presumed that OH groups and quinone groups are generated by carbon dioxide activation. Alternatively, it can also be obtained by reactivating coconut shell activated carbon at a high temperature of 900° C. or higher for a long period of time. In addition to water vapor, highly concentrated carbon dioxide gas is preferable as the reactivation atmosphere. Activated carbon is produced by the method described above, but in order to be used as a cigarette filter, if its average particle size (hereinafter simply referred to as "particle size" means average particle size) exceeds 30 μm, it must be basic enough. Even if the carbon content is high, it is difficult to remove or suppress the charcoal taste caused by the balance between adsorbed components.The fine pulverization process involves pulverizing activated carbon coarsely pulverized to 50 to 100 μm in a ball mill or the like for a long time. It is essential that the activated carbon has a pore diameter of 20 A or less and a pore volume (hereinafter referred to as micropore pore volume) of 0.10 cc/y or more. If the pore volume is less than 0.10 cc/q, vapor phase components such as isoprene, acetone, acetaldehyde, etc. will not be effectively adsorbed, which is undesirable from the standpoint of smoking hygiene or flavor.The activated carbon thus obtained The basicity of
It is determined by adding 0.1 y of activated carbon into 100 ml of aqueous solution, shaking for 2 minutes, and then measuring the pH of the liquid with a PH meter (for example, Industrial Chemistry Magazine 67, 2019 (19
64)). It is presumed that the basicity determined by the above method evaluates the amount of OH- ions ion-exchanged by C1- ions in the aqueous solution. Further, the average particle size was measured by the Coulter counter method, which is one of the particle size measurement methods based on the correction principle (for example, Powder Particle Size Measurement Method, 1, edited by Powder Optics Study Group). Furthermore, the pore diameter and pore volume of activated carbon are the boiling point of liquid nitrogen under normal pressure (-195
．． Using the nitrogen gas adsorption isotherm on the adsorption side at
k1ey) calculation method (for example, Kei Tominaga 7 adsorption method Kyoritsu Shuppan).

However, the ratio (1.5
The value multiplied by 84 x 10-3) was regarded as the total pore volume, and the value subtracted from the cumulative pore volume of pore diameters from 300A to 208A was defined as the pore diameter volume. The activated carbon thus obtained can be used as a filter by sprinkling it on a tow of acetate fibers, combining it with another single piece of acetate fiber, or by mixing it with wood valve fibers, acetate fibers, etc. and forming it into a nonwoven fabric. A method of spraying and adhering it to a nonwoven fabric or tow together with an adhesive, a method of dispersing it in a dispersion medium containing an adhesive polymer such as sodium alginate that provides a highly viscous solution, and creating a paste-like impregnating liquid, and roller printing. Examples include a method of printing on a nonwoven fabric using a printing method used in printing, dyeing, etc., and a method of forming fine particles using a binder such as carboxymethyl cellulose or polyvinyl alcohol and interposing them between acetate fiber tows.

At this time, the amount of activated carbon used is 15 to 10 per filter.
0; Mg is preferred. In this way, the activated carbon of the present invention
The reason why acetaldehyde, formaldehyde, cyanide gas, etc. are specifically adsorbed and removed is not clear, but the reason is that the active surface increases due to the small particle size and... It is presumed that this is because the increase in the amount of base with high basicity acted synergistically on the reaction with acetaldehyde and the like.

In order to improve the aroma and taste, in addition to the removal or suppression of irritating vapor phase components through the selection of high basicity and ultra-fine powder,
The fact that plant-based raw materials are selected as starting materials also contributes greatly. Activated carbon made from synthetic raw materials such as acrylonitrile-based activated carbon fiber and phenolic resin-based activated carbon has been considered as a filter for cigarette smoke, but it has not been put to practical use as a cigarette filter due to the inherent disadvantage that it does not have a good aroma or taste. do not have. As described above, the activated carbon according to the present invention has adsorption properties for isoprene and acetone that are comparable to those of conventional activated carbon, and also has specific adsorption properties for irritating vapor phase components such as acetaldehyde, formaldehyde, and cyanide gas. Therefore, the drawbacks of conventional charcoal filters can be improved.Next, experimental examples will be given to clarify the characteristics of the present invention.

Experimental example 1 The activated carbon used was manufactured as follows.

(1) Wood raw materials Coniferous wood waste with a particle size of 200 to 2000 pm.

(2) Carbonization process The wood chips are heated in an open hearth for a day and a night at 200 to 50% carbonization.
By raising the temperature to 00° C. and heating, a carbide having a yield of 30%, a carbon content of 70%, and a particle size of 100 to 1000 μm was obtained.

(3) Activation treatment a The carbide is placed in a fluidized activation furnace for a residence time of w seconds and a temperature of 120
Activated carbon having a particle size of 30 to 200 pm was obtained by treatment at 0 to 1300°C in an atmosphere containing 10% water vapor.

By pulverizing the activated carbon for 2 millimeters in a ball mill, the particle size was 15 μm and the pore volume of 1 microbore was 0.38 cc/y.
of activated carbon was obtained. (Sample name: 1-a) In addition, by sieving the activated carbon before pulverization, the particle size of 50
pm1 basicity PH9.7, micropore pore volume 0.3
6 cc/y of activated carbon was obtained.

(Sample name: 1-b) Mouth Residence time 5 seconds, temperature 120
0~1300'C1 Treated in an atmosphere containing 10% water vapor,
Activated carbon with a particle size of 30 to 300 pm was obtained.

The activated carbon was pulverized in a ball mill for 24 hours to obtain activated carbon having a particle size of 18 μm, a basicity of PH 9.7, and a micropore pore volume of 0.32 cc/y. (Sample name: 1-c) C. Activated carbon having a particle size of 30 to 200 pm was obtained by treatment in an atmosphere containing 10% water vapor for a residence time of 2.2 pm and a temperature of 1000°C.

The activated carbon was pulverized with a ball mill to obtain activated carbon having a particle size of 15 μm, basicity of pH 9.7, and micropore pore volume of 0.34 cc/f. (Sample name: 1-
d) Experimental Example 2 Commercially available 8-14 mesh coconut shell activated carbon (basicity P
H7 (specific surface area: 600 bo/y) was pulverized to 150-300 pm, and reactivated in a rotary kiln at 900'C in a combustion gas atmosphere for 5 hours.

The activated carbon was pulverized for 10 minutes in a ball mill to obtain activated carbon having a particle size of 15 μm, a basicity of PH 9.5, and a micropore pore volume of 0.4 cc/y. (Sample name: 2-a) Furthermore, the activated carbon after 5 hours of ball mill pulverization was sieved to obtain particle size of 45 μm, basicity of PH 9. & Activated carbon with a micropore pore volume of 0.39 cc/y was obtained. (Sample name: 2-b) Furthermore, by subjecting the commercially available coconut shell activated carbon to ball mill pulverization treatment, the particle size was 1.
5μm1 basicity PH7, micropore pore volume 0.35
Activated carbon of cc/9 was obtained.

(Sample name: 2-c) Experimental example 3 Coniferous wood chips with a particle size of 200 to 2000 pm were mixed with a 50% by weight zinc chloride aqueous solution and heated to 700°C in a multi-stage bed furnace to carbonize and activate the mixture. After the treatment, it is washed with an aqueous hydrochloric acid solution and pulverized in a ball mill to obtain a basicity of PH5.3 and a micropore pore volume of 0.15c.
Activated carbon with c/y and particle size of 15 μm was obtained.

(Sample name: 3-a) Furthermore, by further treating the activated carbon in an air stream containing ammonia gas at 700°C, the particle size was 15 μm, the basicity was 9. ＼ Activated carbon with a micropore pore volume of 0.08 cc/y was obtained.

(Sample name: 3-b) 2 Experimental example 4 After subjecting commercially available polyacrylonitrile fibers to flame resistance treatment in air at 300°C,
Activation treatment was performed in a steam-containing atmosphere at 850°C to obtain fibrous activated carbon, which was then subjected to ball mill pulverization treatment to obtain a product with a particle size of 15 μm, salt tribasicity PH of 9.3, and micropore pore volume of 0.25 cc/ g of activated carbon was obtained.

(Sample name: 4) Experimental example 5 Commercially available novolak type phenolic resin fibers were carbonized in a steam-containing atmosphere at 900°C to obtain Fiber 3 fibrous activated carbon, which was then pulverized in a ball mill to obtain particles with a particle size of 15 μm and
Basicity PH9.2, Micropore pore volume 0.45cc
/y of activated carbon was obtained.

(Sample name: 5) Using the activated carbon obtained in the above experimental example, a cigarette smoke filter was produced by the above four methods.

That is, 15 parts of activated carbon was sprinkled on m parts of an aqueous solution of sodium alginate to make a uniform paste, and then a dry non-woven fabric made of wood bulbs (fabric weight 40y/d1 thickness 2.2m) was printed using a roller printing machine. , 30mg of activated carbon
/A attached sheet was obtained. Use 4 sheets, 4
The sheets are fed side by side so that the striped patterns match, and after being bent into an S-shape or Z-shape, they are twisted by a rotating rotor with a tapered inner diameter and further squeezed into a cylindrical shape. Roll up to make a cylinder with a diameter of 8w0n.
Ta.

After wrapping a thin paper around the outside of this cylinder, the length is 1071
77! An activated carbon impregnated filter was obtained. The length of this filter is 7T! Combined with Un's acetate fiber filter,
A cigarette smoke filter with a length of 17 mm was manufactured as a trial product. Table 1 shows the results of measuring the adsorption rates of cyan gas, acetaldehyde, isoprene, and acetone as vapor phase components for the various cigarette smoke filters trial-produced as described above.

The adsorption rate was determined as follows. That is, a filter manufactured by the above method was manufactured by Japan Monopoly Corporation, and a test cigarette was prepared by removing the filter part from Iraito. It was used and smoked under the following conditions.

Flow rate: 17.5m1/Sec Smoking time: 2sec/times Smoking frequency: 1 time/Min Combustion length: 50Tf$t Number of smokes: 4/Ultra-fine glass fiber filter The adsorption rates of acetaldehyde, isoprene, and acetone are as follows: Extra-fine glass fiber filter 1.95 out of 8 puffs of smoke passed through
mt was introduced into a gas chromatograph, the peak height of the control was set as Hs, and the adsorption rate (F) was determined using the following formula.

F (%) = (H-Hs)/H x 100 In addition, the cyanide gas adsorption rate is based on the tar collected on the ultrafine glass fiber filter and the gas absorption liquid absorbed in the 0.5N (7) NaOH solution. After distillation, the amount of CN was determined by a colorimetric method.

(For example, Journal of the Japanese Society of Public Health 28, 100 (1981
) From the results in Table 1, the following can be devised.

(1) Sample names (1-b) and (2-b) are both made from plant materials, and have appropriate basicity and micropore volume, but the particle size is too large, so acetaldehyde and cyanogen Adsorption rate of system gas is low.

(2) Sample names (1-d), (2-c) and (3-a
) are all made from plant materials and have appropriate particle size and micropore pore volume, but their basicity is too low, so (1-d
) and (2-c) have low adsorption rates overall, and (3-a)
), the adsorption rate of acetaldehyde and cyanide gas is extremely low, and neither of them can achieve the objective.

(3) Sample name (3-b) is made of plant material and has appropriate particle size and basicity, but the adsorption rate of acetaldehyde and cyanide gas is extremely low because the micropore volume is too small. 1) Sample name (1)
-a), (1-c), and (2-b) satisfy all the specified requirements of the present invention, and the adsorption rate of acetaldehyde, isoprene, acetone, and cyanide gas, which are the main components in tobacco smoke, is All products were significantly superior to conventional products, and since each adsorbed component was removed in a well-balanced manner, no charcoal taste was observed.

Claims (1)

[Claims] 1 Made of vegetable raw material, basicity is pH 9 or more, pore volume is 0.10 cc/g or more with a pore diameter of 20 Å or less,
A filter for tobacco smoke with improved flavor and aroma, which contains ultrafine powdered activated carbon having an average particle size of 30 μm or less.