KR20040073534A - Smoking filter and smoking article - Google Patents

Abstract

A smoking filter comprising a hydrotalcite compound having a layered structure in which a plurality of octahedral layers of metal hydroxides are laminated. This smoking filter can selectively remove formaldehyde in the mainstream smoke.

Description

Smoking filter and smoking article {SMOKING FILTER AND SMOKING ARTICLE}

When smoking a smoking article, various chemical components exist in the mainstream smoke sucked by the smoker. The lower aldehydes represented by formaldehyde among these chemical components were difficult to remove by adsorption with a normal smoking filter. Therefore, it is desired to remove aldehydes from the mainstream smoke.

Conventionally, in order to remove formaldehyde in mainstream smoke, it is common to use the filter which added activated carbon as an adsorbent. In addition, the use of various adsorbents has been attempted.

However, the conventionally used adsorbent adsorbs not only formaldehyde but also other components, which may adversely affect the flavor of smoking articles.

It is an object of the present invention to provide a smoking filter which can selectively remove formaldehyde in mainstream smoke.

The present invention relates to smoking filters and smoking articles.

1 is an exploded perspective view of a filter manufactured according to an embodiment of the present invention.

2 is a view showing an apparatus for measuring formaldehyde in cigarette liquor smoke used in the embodiment of the present invention.

3 is a view showing the removal efficiency of formaldehyde by various adsorbents.

4 is a view showing a method for collecting vapor phase components in cigarette mainstream smoke according to an embodiment of the present invention.

FIG. 5 shows gas chromatography of vapor phase components in cigarette mainstream smoke according to an embodiment of the present invention. FIG.

Fig. 6 is a diagram showing the relationship between the vapor pressure of vapor phase components and the component removal rate when hydrotalcite or activated carbon is used as the adsorbent.

Fig. 7A shows the particle size distribution of hydrotalcite particles.

Fig. 7B is a graph showing the relationship between the average particle diameter of the hydrotalcite particles and the ventilation resistance.

8 shows the relationship between the surface area of form hydrotalcite particles and the reduction rate of formaldehyde.

Fig. 9 shows a triple segment type filter of Example 6;

Fig. 10 is a diagram showing a triple segment type filter of Example 6;

11 illustrates a filter in accordance with another embodiment of the present invention.

The smoking filter according to the present invention is a hydrotalcite compound having a layered structure in which a plurality of octahedral layers of metal hydroxides are laminated.

The hydrotalcite compound used in the present invention is the following general formula

M ²⁺ _1-x M ³⁺ _x (OH) ₂ (A ^n- ) _{x /} nmH ₂ O

Here, M ²⁺ is a divalent metal ion selected from the group consisting of Mg, Zn, Ni and Ca, M ³⁺ is Al ion, A ^n- is CO ₃ , SO ₄ , OOC-COO, Cl, Br , F, NO ₃ , Fe (CN) ₆ ^3- , Fe (CN) ₆ ^4- , phthalic acid, isophthalic acid, terephthalic acid, maleic acid, alkenyl acid and derivatives thereof, malic acid, salicylic acid, acrylic acid, adipic acid, succinic acid, citric acid and N-valent anion selected from the group consisting of sulfonic acids, where 0.1 <x <0.4, 0 <m <2.)

Is displayed.

In the smoking filter of the present invention, for example, a hydrotalcite compound having an average particle size of 200 to 800 µm is dispersed in a tow or nonwoven fabric sheet. The fiber is typically composed of cellulose acetate.

The smoking filter of the present invention may be formed by molding a paper sheet made by adding a hydrotalcite compound having an average particle diameter of 10 µm or less.

The smoking filter according to the present invention may have a plurality of filter segments, and at least one filter segment may contain a hydrotalcite compound. In this case, in addition to the filter segment containing a hydrotalcite compound, you may use a charcoal filter segment.

The smoking filter of the present invention may have hydrotalcite particles filled in a space provided between the plurality of filter segments and the filter segment.

The smoking article which concerns on this invention connects the above-mentioned smoking filter and a tobacco rod.

Best Mode for Carrying Out the Invention

MEANS TO SOLVE THE PROBLEM This inventor examined the adsorbent for formaldehyde reduction in mainstream smoke from various viewpoints, and found out that a hydrotalcite compound is effective.

The hydrotalcite compound has a layered structure in which a plurality of octahedral layers of divalent or trivalent metal hydroxides are laminated, and anions are intercalated. An octahedral layer shows basicity called a host. Formaldehyde removal by hydrotalcite compounds is thought to occur as a result of the contribution of basicity of the host and ion exchange by the intercalation anion.

The hydrotalcite compound may be natural or may be a synthetic product. The hydrotalcite compound is a general formula

M ²⁺ _1-x M ³⁺ _x (OH) ₂ (A ^n- ) _{x /} nmH ₂ O

Is displayed. It is most common that the divalent metal ion M ²⁺ is Mg ion, the trivalent metal ion M ³⁺ is Al ion, and the anion A ⁿ⁻ is CO ₃ ^{2 −} or SO ₄ ² −. The divalent metal ion M ²⁺ may be Zn, Ni, or Ca in addition to Mg. The anions are OOC-COO, Cl, Br, F, NO ₃ , Fe (CN) ₆ ^3- , Fe (CN) ₆ ^4- , phthalic acid, isophthalic acid, terephthalic acid, maleic acid, in addition to CO ₃ ^2- or SO ₄ ^2- , Alkenyl acid and its derivatives, malic acid, salicylic acid, acrylic acid, adipic acid, succinic acid, citric acid and sulfonic acid. x is 0.1 <x <0.4, and m is 0 <m <2. The Mg-Al-based hydrotalcite compound is stable in the range of x of 0.20 to 0.33.

When preparing hydrotalcite, alkali carbonate or alkali carbonate and caustic alkali are added to an aqueous solution of aluminum sulfate, aluminum acetate and alum, or an aqueous solution of aluminum acid and water-soluble magnesium salt, and the pH of the reaction mixture is 8.0. It keeps above and makes it react.

In the hydrotalcite compound, for example, the intercalated anion enables control of the micropore size according to the size. In addition, various functionalizations are possible depending on the nature of the anion and the state of the interlayer number.

As a smoking filter which added the hydrotalcite compound, the following various forms can be considered.

(1) A filter in which a hydrotalcite compound is dispersed in a tow or a nonwoven fabric of fibers such as cellulose acetate.

(2) A filter in which a paper sheet made by adding a hydrotalcite compound is molded.

(3) A filter composed of two or more segments, wherein at least one segment is composed of the filter of (1) or (2), and the other segment is composed of a conventional cellulose acetate filter or a charcoal filter.

(4) A filter in which a hydrotalcite compound is filled in a space of a plug-space-plug structure. In this case, the plug is selected from a conventional cellulose acetate filter or charcoal filter, or the filter of (1) or (2). In the case where there are two or more spaces, at least one space may be filled with a hydrotalcite compound, and other spaces may be filled with charcoal.

It is preferable to adjust the particle diameter of a hydrotalcite compound as follows. When using a filter in which a hydrotalcite compound is dispersed in a tow or nonwoven fabric of cellulose acetate fibers or filled into a space of a plug-space-plug structure, the particle size thereof is preferably 200 to 800 µm, and 400 to 600 µm. More preferred. Or when using the filter which shape | molded the paper sheet made by adding the hydrotalcite-type compound, it is preferable that the particle diameter shall be 10 micrometers or less.

Example 1

Hydrotalcite represented by Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O was used. The hydrotalcite was ground and classified to adjust the particle size to 250 to 500 µm. Using this hydrotalcite, the filter 1 shown in FIG. 1 was produced. That is, the molded paper 4 is rolled in a state in which the hydrotalcite 3 is filled in the space provided between the two acetate filter segments 2 and 2 which are rolled up, and the plug-space-plug structure The filter 1 of was produced.

To compare with other adsorbents, activated carbon, high specific surface area carbon, alkali metal salt impregnated activated carbon, amine impregnated activated carbon, activated alumina, magnesium oxide, aluminum oxide, magnesium silicate, zinc oxide, silica gel, zeolite, dry pulp for formalin, gas chromatography ( A filter 1 having a plug-space-plug structure as shown in FIG. 1 was prepared using a column filler for GC) or an absorbent resin.

The filling amount of the adsorbent was the same in either example. In addition, a cigarette for test was prepared by connecting a tobacco part of 12 mg of tar to each filter.

The amount of formaldehyde in the cigarette liquor smoke was measured according to the Canadian process method (2,4-DNPH-HPLC method), and the removal rate of formaldehyde was determined.

First, 9.51 g of 2,4-dinitrophenylhydrazine (DNPH) was dissolved in 1 L of acetonitrile, and then 5.6 mL of 60% perchloric acid was added thereto, followed by addition of ultrapure water to prepare 2 L of the collection liquid.

2, the outline | summary of a measuring apparatus is demonstrated. As shown in FIG. 2, the DNPH trapping liquid 12 was put into the collection bottle 11 for collection. The dose of the strength bottle 11 was 100 mL, and the amount of the DNPH trapping liquid 12 was 80 mL. This century bottle 11 was put in an ice-water bath 13 and ice-cooled. The lower end of the glass tube 14 in which the cigarette 10 was installed was immersed in the collection liquid 12 in the century bottle 11. The glass tube 15 and the Cambridge pad 16 were provided so that the dead volume of the century bottle 11 may be connected, and the Cambridge pad 16 and the automatic smoking machine 17 were connected.

The cigarette 10 was installed in the glass tube 14, and the cigarette 10 was automatically smoked on the standard smoking conditions of ISO standard. That is, the operation of smoking 35 mL for 2 seconds per empty cigarette per cigarette was repeated at 58 second intervals. Formaldehyde was derivatized by DNPH while the mainstream smoke was bubbling. Two cigarettes for measurement were taken. At this time, the pressure loss was adjusted to be the same in all cigarettes using the respective adsorbents.

The derivative produced as described above was measured by high performance liquid chromatography (HPLC). First, the collection solution was filtered and then diluted with a Trizma Base solution (4 mL of collection solution: 6 mL of Trizma Base solution). This solution was measured by HPLC. HPLC measurement conditions are as follows.

Column: HP LiChrospher 100RP-18 (5μ) 250 x 4 mm

Guard column: HP LiChrospher 100RP-18 (5μ) 4 × 4mm

Column temperature: 30 ℃

Detection wavelength: DAD356nm

Injection amount: 20μL

Mobile phase: Three phase gradient (A liquid: Ultrapure water solution containing 30% acetonitrile, 10% tetrahydrofuran and 1% isopropanol, B solution: 65% acetonitrile, 1% tetrahydrofuran and 1% isopropanol) Ultrapure water solution, C liquid: 100% acetonitrile).

When the removal rate E of formaldehyde is W, the amount of formaldehyde measured using the adsorbent-free cigarette is W, and the amount of formaldehyde measured using the adsorbent-filled cigarette is W ',

E = (W-W ') / W.

3 shows the removal rate of formaldehyde by various adsorbents. As can be seen from FIG. 3, it can be seen that formaldehyde can be best reduced when hydrotalcite is used as the adsorbent.

Example 2

Hydrotalcite or activated carbon, which is the most common cigarette adsorbent, was used as the adsorbent, and the removal rate of the vapor phase components in the cigarette mainstream smoke was determined.

As in Example 1, hydrotalcite or activated carbon having a particle diameter of 250 to 500 µm was prepared, and each was filled with 50 mg of a filling amount to prepare a filter as shown in FIG. A 12 mg tar portion of tobacco was connected to this filter to prepare a test cigarette.

4 and 5, a method of measuring the removal rate of vapor phase components in cigarette mainstream smoke will be described.

4 is a diagram illustrating a method of collecting vapor phase components. As shown in FIG. 4, the cigarette 10 is installed in the automatic smoking machine 17, the cigarette 10 is automatically smoked under the standard smoking conditions of ISO compliance, and the particulate form in the mainstream smoke is removed by a Cambridge filter. The vapor phase was collected in gas bag 20. At this time, the operation of smoking 35 mL for 2 seconds per empty cigarette per cigarette, was repeated at 58 second intervals. 10 cigarettes (harmonized condition: 22 ° C., 60% humidity) were automatically smoked.

5 is a diagram illustrating gas chromatography. As shown in FIG. 5, a certain amount of vapor phase components in the gas bag 20 were collected in the sample loop 21, and after injecting a standard gas, it was injected into the gas chromatograph 22. As shown in FIG. The components were separated in the column (DB-WAX), the components were detected by a detector, and the component amounts were analyzed using the program of the personal computer 23. The peak area of each vapor phase component was divided by the peak area of the standard gas to obtain an analysis value. The removal rate E of each vapor phase component is a component analysis value measured using a cigarette without adsorbent A, and a component analysis value measured using a cigarette packed with adsorbent A ',

It is represented by E = (A-A ') / A.

6 shows the relationship between the vapor pressure of the vapor phase component and the component removal rate. In the case of using activated carbon as the adsorbent from Fig. 6, the removal rate was increased as the vapor pressure of the vapor phase component increased. In addition, when hydrotalcite is used as the adsorbent, it can be seen that the removal rate is high only specifically for formaldehyde, showing selective removal performance.

Example 3

For example, when hydrotalcite is used in the cigarette filter of FIG. 1, it is necessary to appropriately adjust the size of hydrotalcite in order to control aeration resistance and tar / nicotine outflow amount.

By assembling hydrotalcite, samples with different particle size distribution can be prepared. In this case, the sample is distinguished by the average particle diameter. 7A shows three samples having an average particle diameter of 250 µm, 500 µm and 800 µm.

Next, using hydrotalcite particles having different average particle diameters, a filter having the form of FIG. 1 was produced at various packing amounts. For reference, charcoal was also used to produce a filter equivalent to the product having the form of FIG.

In these filters, the ventilation resistance at the suction flow rate of 1050 mL / min was investigated. It is calculated here except for the airflow resistance generated in the two acetate filter segments 2 and 2 of FIG.

7B shows the relationship between the average particle diameter and the ventilation resistance. It is found from FIG. 7B that the airflow resistance is high when the particles having an average particle diameter of 250 µm are used, and the airflow resistance is low when the particles having an average particle diameter of 800 µm are used. Therefore, in designing the product, it was found that it is appropriate to use hydrotalcite particles having an average particle diameter in the range of 400 to 600 µm.

In addition, in the case of using the granulated particles, hydrotalcite particles having a target particle size can be obtained by using any granulation method such as electric granulation, compression molding, coating granulation, extrusion molding, or the like. However, in order to avoid the crushing of the hydrotalcite particles in the manufacture of the filter, it is preferable to use a granulation method in which granulated hydrotalcite particles having an appropriate hardness are obtained. When the hardness of the hydrotalcite particles was in the range of 300 to 3000 g / mm ² , it was found that crushing during the manufacture of the filter can be prevented.

Example 4

In this embodiment, it is shown that the reduction rate of formaldehyde in the mainstream smoke by hydrotalcite depends on the surface area of the hydrotalcite particles.

As the granulation method, various granulated hydrotalcite particles were prepared by using electric granulation (A), compression molding (B), or extrusion molding (C). The average surface area per unit weight of hydrotalcite particles was calculated using a laser scattering particle size distribution analyzer.

Using a hydrotalcite particle having various surface areas, a filter having the form of FIG. 1 was produced. At this time, the total surface area of the filled hydrotalcite particles was adjusted by adjusting the filling amount. The relationship between the total surface area of the hydrotalcite particles and the reduction rate of formaldehyde in the mainstream smoke was investigated. The results are shown in FIG.

It has been found from FIG. 8 that the larger the total surface area of the hydrotalcite particles, the lower the formaldehyde can be from mainstream smoke. This tendency does not depend on the method of assembling the hydrotalcite particles.

Example 5

In this Example, the reduction rate of formaldehyde in the mainstream smoke by the hydrotalcite-added paper filter and the granulated hydrotalcite-added cellulose acetate filter was investigated.

A paper sheet was made while adding hydrotalcite particles having an average particle diameter of 10 µm or less, and the paper sheet was molded to prepare a paper filter 7 shown in FIG. For comparison, a filter was prepared by molding a paper sheet to which no hydrotalcite particles were added.

Moreover, the filter which disperse | distributed granulated hydrotalcite particle | grains to the tow of cellulose acetate fiber was produced. For comparison, a cellulose acetate filter was added without adding hydrotalcite particles.

In addition, the length of the filter is 25 mm, and as much as possible the ventilation resistance.

These filters were used to investigate the reduction of formaldehyde in the mainstream smoke. The results are shown in Table 1.

As shown in Table 1, in the paper filter containing hydrotalcite particles, the amount of formaldehyde outflow per tar was lower than that of the acetate filter containing hydrotalcite particles. This is considered to be because the contact surface area is improved as a result of adding hydrotalcite particles having an average particle diameter of 10 µm or less to the paper sheet with high dispersion.

Table 1

HT amount (mg) Length (mm) Breathing resistance (mmWG) Tar release (mg / skin) FA outflow (㎍ / opening) FA / tar (-) Acetate filter 0 25 65.5 12.53 72.86 5.81 146.7 25 61.9 12.19 35.70 2.93 Paper Filter 0 25 65.0 7.31 48.56 6.64 48.3 25 65.5 6.42 14.03 2.19

Example 6

In the present embodiment, the combination of the hydrotalcite filter and the charcoal filter shows that the organic vapor component reduction rate can be increased.

Triple segment filters shown in Tables I, II and III were prepared. Each segment used will be described. The acetate filter segment bundles the tow of cellulose acetate fibers and has a length of 7 mm. The hydrotalcite (HT) filter segment is made by dispersing 70 mg of hydrotalcite particles in a tow of cellulose acetate fibers to form a length of 10 mm. The charcoal filter segment disperse | distributes 70 mg of charcoal particle in the tow of cellulose acetate fiber, and makes it 10 mm in length.

In Fig. 10, the filter of III in Table 2 is shown. As shown in this figure, the charcoal filter segment 5 is arrange | positioned at the tobacco flesh side, the HT filter segment 6 at the middle, and the acetate filter segment 2 at the inlet side.

These filters were used to investigate the reduction of total organic vapor (TOV) and the reduction of formaldehyde (FA) in the mainstream smoke. The results are shown in Table 2.

As shown in Table 2, the filter of III can reduce the total organic vapor by the action of the charcoal filter, and can also reduce formaldehyde by the action of the hydrotalcite (HT) filter.

Table 2

Tobacco side middle Intake side TOV reduction rate (%) FA reduction rate (%) I Charcoal filter Acetate filter Acetate filter 62.7 67.2 Ⅱ Acetate filter HT filter Acetate filter 20.8 69.3 Ⅲ Charcoal filter HT filter Acetate filter 64.8 71.9

Additive weight: 70mg / 10mm

Filter length: Tobacco side 10mm, middle 10mm, inlet side 7mm

Filter chip ventilation resistance: 72mmWG / 27mm

Ventilation Holes: None

In the filter according to the present invention, various modification examples as follows can be considered.

For example, in the filter having the structure as shown in Fig. 1, another filter segment may be used instead of at least one acetate filter segmenter 2. The other filter segment may be a hydrotalcite filter segment or a charcoal filter segment. In the case of using the charcoal filter segment, it is preferable to arrange the tobacco filter side as shown in FIG.

In Fig. 10, a hydrotalcite compound is formed by dispersing a hydrotalcite compound in a tow of cellulose acetate fibers as a hydrotalcite filter segment. However, a sheet of paper sheet formed by adding a hydrotalcite compound may be used.

A four segment filter may be manufactured by adding another filter segment to the filter having the structure of FIG.

11, the filter which consists of the charcoal filter segment 5, the space filled with the hydrotalcite particle | grains 3, the hydrotalcite (HT) filter segment 6, and the acetate filter segment 2 is carried out. You may use it.

Also in this case, the hydrotalcite filter segment 6 may be an acetate filter base or a paper filter base. It may be the reverse of Fig. 11 in which the space filled with the HT particles 3 and the HT filter segment 6 are arranged. In Fig. 11, the space is filled with HT particles, but char particles may be filled.

According to the present invention, it is possible to provide a smoking filter and a smoking article that can effectively reduce formaldehyde in the mainstream smoke.

Claims (9)

A smoking filter comprising the addition of a hydrotalcite compound having a layered structure in which a plurality of octahedral layers of a metal hydroxide are laminated. The smoking filter according to claim 1, wherein the hydrotalcite compound is represented by the following general formula: M ²⁺ _1-x M ³⁺ _x (OH) ₂ (A ^n- ) _{x /} nmH ₂ O Here, M ²⁺ is a divalent metal ion selected from the group consisting of Mg, Zn, Ni and Ca, M ³⁺ is Al ion, A ^n- is CO ₃ , SO ₄ , OOC-COO, Cl, Br , F, NO ₃ , Fe (CN) ₆ ^3- , Fe (CN) ₆ ^4- , phthalic acid, isophthalic acid, terephthalic acid, maleic acid, alkenyl acid and derivatives thereof, malic acid, salicylic acid, acrylic acid, adipic acid, succinic acid, citric acid and N-valent anion selected from the group consisting of sulfonic acids, where 0.1 <x <0.4, 0 <m <2.) The smoking filter according to claim 1, wherein a hydrotalcite compound having an average particle diameter of 200 to 800 µm is dispersed in a tow or nonwoven sheet of fiber. The smoking filter according to claim 3, wherein the fiber is made of cellulose acetate. The smoking paper filter according to claim 1, wherein a paper sheet made of paper is formed by adding a hydrotalcite compound having an average particle diameter of 10 µm or less. The smoking filter according to claim 1, wherein the smoking filter has a plurality of filter segments, and at least one filter segment contains a hydrotalcite compound. The filter for smoking according to claim 6, further comprising a charcoal filter segment in addition to a filter segment containing a hydrotalcite compound. The smoking filter according to claim 1, further comprising a plurality of filter segments and hydrotalcite particles filled in a space provided between the filter segments. A smoking article according to any one of claims 1 to 8, wherein a smoking rod and a tobacco rod are connected.