阅读说明：本技术 吸烟物品用过滤嘴及其制造方法 (Filter for smoking article and method for manufacturing same ) 是由 稻垣道弘 四分一弘 于 2018-06-18 设计创作，主要内容包括：一种吸烟物品用过滤嘴,其包含：滤材(2),其具有具备第1端面及第2端面和侧面的圆柱形状,且包含脊部与谷部交替排列的波形膜(21),脊部及谷部从第1端面延伸至第2端面,并形成有可使空气从第1端面流通至第2端面的多个空气流通路(22)；多个粒子(3),其配置于空气流通路；以及卷绕纸(4),其以包覆侧面的方式卷装滤材。(A filter for a smoking article comprising: a filter medium (2) having a cylindrical shape having a 1 st end surface, a 2 nd end surface, and a side surface, and including a corrugated film (21) in which ridges and valleys are alternately arranged, the ridges and valleys extending from the 1 st end surface to the 2 nd end surface, and a plurality of air flow passages (22) through which air can flow from the 1 st end surface to the 2 nd end surface; a plurality of particles (3) disposed in the air flow path; and a winding paper (4) for winding the filter medium in a manner of covering the side surface.)

1. A filter for a smoking article comprising:

a filter medium having a cylindrical shape including a 1 st end surface, a 2 nd end surface, and a side surface, and including a corrugated film in which ridge portions and valley portions are alternately arranged, the ridge portions and the valley portions extending from the 1 st end surface to the 2 nd end surface, and a plurality of air flow passages capable of allowing air to flow from the 1 st end surface to the 2 nd end surface are formed;

a plurality of particles disposed in the airflow path; and

and a winding paper for winding the filter medium so as to cover the side surface.

2. The filter for smoking articles according to claim 1, wherein,

the corrugated film is a film formed from a molten film material.

3. The filter for smoking articles according to claim 1 or 2, wherein,

the corrugated film has a thickness of 30 to 200 μm.

4. The filter for smoking articles according to any one of claims 1 to 3, wherein,

the corrugated film has a tensile elongation of 100% or more.

5. The filter for smoking articles according to any one of claims 1 to 4, wherein,

the corrugated film has a wave pitch of 0.5mm to 1.5 mm.

6. The filter for smoking articles according to any one of claims 1 to 5, which comprises the wavy film at a packing rate of 10 to 40%.

7. The filter for smoking articles according to any one of claims 1 to 6, wherein,

the particles have a particle size of 12 to 70 mesh in accordance with JIS Z8801-1 (2006).

8. The filter for smoking articles according to any one of claims 1 to 7,

the filter for smoking articles contains the particles in an amount of 20 to 60mg per 10mm of length when the circumference of the filter is 24.0 mm.

9. The filter for smoking articles according to any one of claims 1 to 8, wherein,

the filter for smoking articles has a circumference of 16-26 mm.

10. The filter for smoking articles according to any one of claims 1 to 9, wherein,

the film is a plastic film.

11. The filter for smoking articles according to any one of claims 1 to 10, wherein,

the film is selected from a polypropylene film, a polybutylene succinate-adipate film, a polyethylene film, a polyvinyl chloride film, a polyethylene terephthalate film, a polylactic acid film, a cellulose acetate film, and a film formed of 2 or more materials constituting these films.

12. The filter for smoking articles according to any one of claims 1 to 11,

the particles have a particle size of 1 to 500m²BET specific surface area in g.

13. The filter for smoking articles according to any one of claims 1 to 12, wherein,

the particles are selected from the group consisting of cellulose particles, cellulose acetate particles, calcium carbonate particles, activated carbon particles having a low degree of activation, unactivated carbon particles, and combinations of these particles.

14. The filter for smoking articles according to any one of claims 1 to 12, wherein,

the particles are selected from the group consisting of particles of hydrotalcite-like compounds and particles of anion exchange resins.

15. The filter for smoking articles according to any one of claims 1 to 14, wherein,

the filter for smoking articles has a length of 50-140 mmH per 10mm₂The ventilation resistance of O.

16. The filter for smoking articles according to any one of claims 1 to 15, wherein,

the filter for smoking article has a thickness of 2 to 10mm^＊A hardness of 10.

17. A filter for a smoking article comprising:

low filtration filter having a filter ventilation resistance of 90mmH₂A tar filtration rate of 40% or less in the case of O;

a plurality of particles disposed in the gaps of the low filtration medium; and

and a winding paper around which the low filtration filter material is wound.

18. The filter for smoking articles according to claim 17, wherein,

the low-filtration filter medium has a cylindrical shape having a 1 st end surface, a 2 nd end surface, and a side surface, and includes a corrugated film in which ridge portions and valley portions are alternately arranged, the ridge portions and the valley portions extend from the 1 st end surface to the 2 nd end surface, and the filter medium is formed with a plurality of air flow passages through which air can flow from the 1 st end surface to the 2 nd end surface.

19. A smoking article comprising a filter for a smoking article according to any one of claims 1 to 18.

20. A cigarette, comprising:

a filter for a smoking article according to any one of claims 1 to 18;

a tobacco rod comprising a tobacco filler material and attached to one end of the filter; and

and a tipping paper wrapped around the filter and the tobacco rod so as to connect the filter and the tobacco rod.

21. A method of manufacturing a filter for a smoking article, the method comprising:

adding a plurality of particles to the corrugated film;

a step of disposing the particles in the air flow passage by forming a filter material by collecting the corrugated film so as to have a plurality of air flow passages in a longitudinal direction and to form a cylindrical shape as a whole; and

and a step of winding the filter medium with a winding paper to obtain a filter.

22. The method of manufacturing a filter for a smoking article according to claim 21, further comprising a step of spraying a liquid binder on the corrugated film after the step of adding the plurality of particles to the corrugated film.

23. The method of producing a filter for a smoking article according to claim 21 or 22, further comprising a step of heating the filter before or after the step of wrapping the filter with the wrapping paper to obtain a filter.

Technical Field

The present invention relates to a filter for smoking articles and a method for manufacturing the same.

Background

As a filter for a smoking article, an acetate filter using a cellulose acetate fiber bundle (cellulose acetate tow) as a filter medium is generally used. On the other hand, as a filter for smoking articles, a film filter is known which is formed by folding a film material so as to form air flow passages in the longitudinal direction after pleating the film material, and wrapping the folded film material with wrapping paper (see, for example, british patent No. 2118423 and japanese patent application laid-open No. 9-294577). The film filter has characteristics that the transmittance of a component that contributes significantly to the flavor is higher than that of an acetate filter, and a user can easily feel the flavor when smoking.

Disclosure of Invention

Problems to be solved by the invention

The present inventors have focused on the problem that a membrane filter is insufficient in filter hardness and filter ventilation resistance as compared with an acetate filter as a cause of low versatility of the membrane filter in smoking articles. If the filter hardness is insufficient, the user's feeling of use (e.g., feeling of gripping and feeling of gripping) is reduced, and if the filter ventilation resistance is insufficient, the user feels that it is difficult to inhale. Accordingly, an object of the present invention is to provide a membrane filter for smoking articles, which has sufficient filter hardness and sufficient filter ventilation resistance while maintaining the filtration characteristics of the membrane filter.

Means for solving the problems

According to one aspect, there is provided a filter for a smoking article comprising:

a filter medium having a columnar shape including a 1 st end surface, a 2 nd end surface, and a side surface, and including a corrugated film in which ridge portions and valley portions are alternately arranged, the ridge portions and the valley portions extending from the 1 st end surface to the 2 nd end surface, and a plurality of air flow passages capable of allowing air to flow from the 1 st end surface to the 2 nd end surface are formed;

a plurality of particles disposed in the air flow path; and

and a winding paper for winding the filter medium so as to cover the side surface.

According to a further aspect, there is provided a filter for a smoking article comprising:

low filtration filter having a filter ventilation resistance of 90mmH₂A tar filtration rate of 40% or less in the case of O;

a plurality of particles disposed in the gaps of the low filtration medium; and

and a winding paper around which the low filtration medium is wound.

Further, according to another aspect, there is provided a smoking article comprising the above filter for a smoking article.

Further, according to other aspects, there is provided a cigarette comprising:

a filter for smoking articles as described above;

a tobacco rod containing a tobacco filler and connected to one end of the filter; and

and a tipping paper wrapped around the filter and the tobacco rod so as to connect the filter and the tobacco rod.

Further, according to another aspect, there is provided a method of manufacturing a filter for a smoking article, the method comprising:

adding a plurality of particles to the corrugated film;

collecting the corrugated film so as to have a plurality of air flow paths in a longitudinal direction and to form a filter material in which the corrugated film is integrally formed in a cylindrical shape, thereby disposing the particles in the air flow paths; and

and a step of wrapping the filter medium with a wound roll to obtain a filter.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a membrane filter for a smoking article having sufficient filter hardness and sufficient filter ventilation resistance can be provided while maintaining the filtration characteristics of the membrane filter.

Drawings

Fig. 1 is a cross-sectional view showing an example of a filter for a smoking article.

Fig. 2 is a diagram showing the film thickness and the film width of the corrugated film.

Fig. 3 is a graph showing the relationship between the amount of particles added and the ventilation resistance of the filter.

Fig. 4 is a graph showing the relationship between the amount of particles added and the hardness of the filter.

Fig. 5 is a graph showing the relationship between the filter ventilation resistance and the tar permeability.

Fig. 6 is a graph showing the results of the release amount ratio of the semi-volatile component.

Figure 7A is a schematic representation of a cigarette evaluated in example 2.

Figure 7B is a schematic representation of the cigarette evaluated in example 2.

Detailed Description

The present invention will be described in detail below, but the following description is intended to illustrate the present invention in detail and is not intended to limit the present invention.

1. Filter for smoking article

Fig. 1 shows a cross-sectional view of an example of a filter for a smoking article. As shown in fig. 1, a filter 1 for a smoking article includes:

a filter medium 2 having a columnar shape including a 1 st end surface, a 2 nd end surface, and a side surface, and including a corrugated film 21 in which ridge portions and valley portions are alternately arranged, the ridge portions and the valley portions extending from the 1 st end surface to the 2 nd end surface, and a plurality of air flow passages 22 through which air can flow from the 1 st end surface to the 2 nd end surface;

a plurality of particles 3 disposed in the airflow passage 22; and

and a winding paper 4 for winding the filter medium so as to cover the side surface.

According to other aspects, the filter 1 for a smoking article comprises:

a filter medium 2 formed by collecting a corrugated film 21 so as to have a plurality of air flow passages 22 in the longitudinal direction and to have a cylindrical shape as a whole;

a plurality of particles 3 arranged in the airflow passage 22; and

a winding paper 4 around which the filter medium 2 is wound.

In the following description, a filter for a smoking article may be simply referred to as a filter.

The filter medium has a cylindrical shape having a 1 st end surface, a 2 nd end surface, and a side surface. Among them, the filter medium is formed by collecting a corrugated film so as to form a plurality of air flow paths in the longitudinal direction (collecting process), and the filter medium is wound around a winding paper, so that the 1 st end face and the 2 nd end face look like "holes" due to the presence of the air flow paths, are not flat in a strict sense, and have irregularities on the surfaces thereof in a strict sense. The 1 st end face and the 2 nd end face do not need to be perfectly circular in the strict sense, and may be elliptical.

The corrugated film (corrugated film)21 constituting the filter medium is a corrugated pleated film, that is, a film in which ridges 21a and valleys 21b are alternately arranged (see fig. 2). The ridges and valleys of the corrugated film extend from the 1 st end surface to the 2 nd end surface of the filter medium, and a plurality of air flow passages are formed to allow air to flow from the 1 st end surface to the 2 nd end surface.

The corrugated film can be produced by subjecting the film to a known treatment for imparting a corrugated wrinkle. This process is also called pleat process, crimp process (crimp process), or crepe (crepe) process, and is well known. For example, japanese patent application laid-open No. 9-294577 discloses a treatment for imparting wrinkles by passing a raw material sheet of a tobacco paper filter between a pair of rollers for imparting wrinkles.

The corrugated film is preferably a film formed from a molten film material. A method of forming a film from a molten film material is known, and examples thereof include a T-die method (casting method) and a blow molding method. After forming from the molten film material, the film may be stretched in a uniaxial direction or a biaxial direction.

When the corrugated film is a film formed from a molten film material, air does not substantially permeate the film. In this case, the corrugated film is not composed of an aggregate of fibers (e.g., paper or nonwoven fabric). That is, the corrugated film is not a film formed into a sheet by applying a compressive force and heat to fibers.

When the corrugated film is formed of a molten film material, the corrugated film has a dense structure on the surface as compared with a corrugated film formed of an aggregate of fibers. The surface characteristics (i.e., surface density) of the film contribute to preventing particles disposed in the air flow passages from being buried in the thickness direction of the film. When the particles are arranged in the air flow passage without being embedded in the film, the particles can efficiently contribute to the increase in the filter ventilation resistance and can efficiently contribute to the increase in the filter hardness.

More preferably, the corrugated film is a high molecular polymer film. It is further preferable that the corrugated film is a plastic film. Specifically, the corrugated film is a polyolefin film or a polyester film. More specifically, the corrugated film is a polypropylene film, a polybutylene succinate/adipate film, a polyethylene film, a polyvinyl chloride film, a polyethylene terephthalate film, a polylactic acid film, a cellulose acetate film, or a film formed of 2 or more materials constituting these films. The corrugated membrane may be a biodegradable membrane. When the corrugated film is formed of 2 or more kinds of film materials, the film materials are combined (mixed) in a granular state of the raw materials, and melted and formed into a film, thereby producing the corrugated film. In the case where the corrugated film is composed of 2 or more kinds of film materials, various physical properties such as heat resistance and tensile elongation of the corrugated film can be adjusted.

The corrugated film generally has a thickness of 30 μm to 200 μm, preferably 30 μm to 100 μm. The thickness here means the thickness of the film before the treatment for imparting wrinkles. When the film has a thickness within the above range, local damage (cracks) is less likely to occur during treatment for imparting wrinkles.

The corrugated film generally has a wave pitch of 0.5mm to 1.5mm, preferably 0.5mm to 1.0 mm. The wave pitch is an average value of intervals between adjacent pleats and between adjacent pleats when the pleats of the corrugated film are stretched in a planar shape. When the wave pitch is more than 1.5mm, it is difficult to form a perfect circle in the cross section when the corrugated film is gathered and the entire corrugated film is formed into a cylindrical shape, and a pitch of less than 0.5mm is not preferable from the viewpoint of accuracy of imparting wrinkles and durability of a roll for imparting wrinkles.

In 1 piece of the corrugated film, the wrinkles (i.e., waves) are preferably regularly attached (i.e., at the same pitch) to the entire face of the film.

The corrugated film generally has a tensile elongation of 100% or more, preferably has a tensile elongation of 100% to 1000%, more preferably has a tensile elongation of 150% to 800%. The tensile elongation here is a value measured by subjecting a film before treatment for imparting wrinkles to the film to a tensile test. The tensile elongation can be determined by performing a tensile test in accordance with astm d882 and substituting the test results into the following formula.

Tensile elongation (%) of 100 × (L-L)₀)/L₀

Here, L represents the film length at break, L₀Indicates the initial (pre-test) film length.

If the film has a tensile elongation within the above range, local damage (cracks) is less likely to occur in the treatment for imparting wrinkles. When the wavy film is damaged (cracked), air passes through a part of the wavy film, and thus the tar/nicotine filtration rate per the ventilation resistance of the filter is improved when the filter is formed.

The greater the tensile elongation of the film, the greater the filter ventilation resistance of the filter produced (see fig. 3). Therefore, the material of the film is selected based on the tensile elongation characteristics, and the filter ventilation resistance can be adjusted.

The corrugated film is gathered so as to have a plurality of air flow passages in the longitudinal direction and a cylindrical shape as a whole, thereby forming a filter medium. That is, the filter medium is formed of a corrugated film, has a plurality of air flow passages defined by gaps of the corrugated film and running in the longitudinal direction, and has a cylindrical shape as a whole.

The filling degree of the corrugated film to the filter, that is, the filling rate of the corrugated film is preferably 10 to 40%, more preferably 20 to 40%. The "filling rate" is defined by the following numerical expression.

Filling factor (%) { (film thickness × film width) ÷ filter cross-sectional area } × 100

In fig. 2, the film thickness and the film width of the corrugated film are represented by t and w, respectively. The film width (w) is a width of the film measured in a state where the wrinkle is stretched.

If the filling rate is less than 10%, particles arranged in the air flow passage are difficult to be held in the air flow passage and are likely to fall off. In this case, since the proportion of the air flow path is high, a large amount of particles must be added to adjust the ventilation resistance, and as a result, the filter surface tends to be uneven. On the other hand, if the filling rate is more than 40%, the high-speed molding of the filter becomes difficult due to the repulsive force of the film, and when the filter is wound around a paper roll, perforation of the lap portion after the glue application tends to occur. The filling rate may be appropriately adjusted within the above range in consideration of the desired filter hardness and filter ventilation resistance.

When the corrugated films are gathered to form the filter medium, 1 piece of the corrugated film may be gathered in a cylindrical shape so as to be folded, or a plurality of pieces of the corrugated film may be gathered in a cylindrical shape to form the filter medium.

As described above, if the corrugated films are gathered to form the filter medium, the gaps of the corrugated films form a plurality of air flow passages running in the longitudinal direction. In the present invention, a plurality of particles are arranged in the air flow passage. If the particles are disposed in the air flow path, the particles contribute to an increase in the filter hardness and an increase in the filter ventilation resistance of the membrane filter (see fig. 3 and 4). The particles are preferably arranged so as to block the air flow passage without being buried in the corrugated film, and thereby can efficiently contribute to the increase in the hardness of the filter and the increase in the filter ventilation resistance.

The particles preferably have a particle size of 10 to 70 mesh (i.e., 1.7 to 0.212mm mesh), more preferably 12 to 70 mesh (i.e., 1.4 to 0.212 μm mesh), and still more preferably 10 to 42 mesh (i.e., 1.7 to 0.355mm mesh), in accordance with JIS Z8801-1 (2006). The particle size of 10 to 70 mesh means a particle size passing through a sieve of 10 mesh but not passing through a sieve of 70 mesh.

When the particles have a particle diameter within the above range, the particles block the air flow passage to efficiently contribute to the increase in the filter ventilation resistance, and can be easily and reliably held in the air flow passage without using an adhesive such as an adhesive or a plasticizer. If particles that do not pass through a 10-mesh sieve are used, the surface of the filter tends to exhibit irregularities of the particles, and the quality of the sizing may be affected in the step of sizing tipping paper for joining the filter to the tobacco rod. If particles passing through a sieve having a mesh opening 1 size smaller than that of a 70-mesh sieve are used, the particles are likely to fall off from the cut end face of the filter.

The particles may be arranged in the air flow path without using a binder such as an adhesive or a plasticizer, or may be arranged in the air flow path using a binder. As the binder used as the binder, for example: polyvinyl acetate; polyvinyl alcohol; polyethylene glycol; water-soluble esters or ethers; polysaccharides such as pectin, agar, starch, guar gum, carrageenan, gellan gum, xanthan gum, locust bean gum, gum arabic, tamarind gum, alginic acid, and alginates; grease; natural macromolecules (e.g., proteins); waxes such as paraffin wax; cellulose derivatives such as CMC (carboxymethyl cellulose), HEC (hydroxyethyl cellulose), and HPMC (hydroxypropyl methyl cellulose). As the plasticizer used as the adhesive, a substance having plasticization against the film used may be used. As the plasticizer, triacetin, triethyl citrate, or the like can be used for the cellulose acetate film.

When a binder is used, the falling-off of particles can be reduced. The binder can be used by coating the surface of the film or the surface of the particles. By selecting the type of binder to be used, specific components in the tobacco components can be selectively removed, and a more preferable flavor can be achieved.

In addition, in the case of using a film having a characteristic of melting by temperature rise without using an adhesive, the film is locally melted by applying heat to the filter before or after the filter is formed, thereby increasing the contact area with the particles; or partially welded to the particles, whereby the particles can be reliably retained in the airflow passage.

When the circumference of the filter is 24.0mm, the particles are contained in an amount of preferably 20 to 100mg, more preferably 20 to 60mg, and still more preferably 20 to 50mg per 10mm of the filter length on average. The amount of the particles to be added may be appropriately adjusted within the above range in consideration of the desired ventilation resistance of the filter.

When the circumferential length of the filter changes, the amount of the particles to be added may be calculated so that the amount of the particles to be added per volume of the filter is the same. Specifically, the amount of particles added Ax [ mg ] when the circumferential length of the filter is X [ mm ] can be calculated by the following calculation formula.

A_x＝A₂₄×V_x/V₂₄

A₂₄The amount of particles added is [ mg ] when the circumference of the filter is 24.0mm]，V_xThe circumference of the filter tip is X mm]Volume of filter in the case of [ mm ]³]，V₂₄The volume of the filter [ mm ] is defined as the circumference of the filter of 24.0mm³]。

For example, when the circumference of the filter is 20.0mm, the particles are contained in an amount of preferably 13.9 to 41.7mg, more preferably 20.8 to 34.7mg per 10mm of the filter length on average.

The particles are preferably particles having relatively low adsorption performance to the entire vapor phase component of the mainstream smoke, that is, particles having a relatively small specific surface area. Specifically, it is preferable to have a thickness of 1 to 500m²Particles having a BET specific surface area of 1 to 100m are more preferable²Particles of BET specific surface area per g. 1m of the lower limit²The term,/g, means below the detection limit.

The particles may be low-adsorptive particles that do not substantially remove the entire vapor phase component of the mainstream smoke. If the low-adsorption particles are added to a filter medium comprising a corrugated membrane, increased tobacco flavor (i.e., increased satisfaction) can be provided to the user due to the low filtration performance of the filter medium and the low adsorption performance of the particles.

The low-adsorption particles are particles selected from, for example, cellulose particles, cellulose acetate particles, calcium carbonate particles, activated carbon particles having a low degree of activation, unactivated carbon particles, and combinations thereof. These particles do not substantially remove the entire vapor phase component of mainstream smoke.

Cellulose particles and cellulose acetate particles are referred to WO 2013/084661.

The cellulose acetate particles may have any average degree of acetylation, but cellulose triacetate particles having an average degree of acetylation of a high value of 2.76 to 3.0 are preferable in terms of not absorbing various volatile flavor components present in cigarette packs during cigarette storage. The average degree of acetification can be determined by titration: ASTM D871-96. The acetyl substitution degree of cellulose acetate determined by this measurement method is defined as "average degree of acetylation" because it shows a normal distribution. For example, cellulose acetate particles may be prepared by: commercially available cellulose triacetate flakes are used as a raw material, and the raw material is pulverized into a desired particle size by a pulverizer such as a mill, and classified by a sieve. As another method, preparation may be made by: a commercially available product in the form of a cellulose triacetate flake is used as a raw material, and is pulverized by a pulverizer such as a mill, the obtained powder is compression-molded by a compression-type granulating apparatus, and the obtained molded body is further pulverized and classified.

The cellulose particles may be prepared by the following method: a commercially available cellulose powder such as microcrystalline cellulose is used as a raw material, compression-molded by a compression-type pelletizer, and the obtained molded body is pulverized and classified.

The activated carbon particles having a low activation degree may be set to have a particle size of 300 to 1000m²BET specific surface area of activated carbon particles. The carbon particles that are not activated may have a particle size of 1 to 300m²Carbon particles per g of BET specific surface area.

Alternatively, the particles may be selectively adsorptive particles in which a specific stimulating component is selectively removed from a vapor phase component of mainstream smoke. If the selective adsorbent particles are added to a filter medium comprising a corrugated film, irritation can be suppressed and an increased tobacco flavor (i.e., increased satisfaction) can be provided to the user due to the low filtration performance of the filter medium and the selective component removal performance of the particles.

The selectively adsorbing particles are particles selected from, for example, particles of hydrotalcite-like compounds and particles of anion exchange resins (for example, Amberlite, an anion exchange resin commercially available from Organo corporation). Particularly, the particles of the hydrotalcite-like compound can selectively remove aldehydes from the vapor phase component of the mainstream smoke.

The particles of the hydrotalcite-like compound are particles of a known compound having a layered structure similar to hydrotalcite, and for example, refer to WO 2003/056947.

Specifically, the hydrotalcite-like compound is represented by the following general formula,

[M²⁺ _1-xM³⁺ _x(OH)₂][(A^n-)_x/n·mH₂O]

here, M²⁺Is a 2-valent metal ion selected from Mg, Zn, Ni and Ca, M³⁺Is Al ion, A^n-Is selected from CO₃、SO₄、OOC-COO、Cl、Br、F、NO₃、Fe(CN)₆ ^3-、Fe(CN)₆ ^4-N-valent anions in 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 sulfonic acid, wherein x is more than 0.1 and less than 0.4, and m is more than 0 and less than 2.

In the above formula, M is preferred²⁺Is Mg ion, M³⁺Is Al ion, A^n-Is CO₃ ^2-Or SO₄ ^2-X is more than 0.1 and less than 0.4, and m is more than 0 and less than 2. The Mg-Al series hydrotalcite compound is stable when x is in the range of 0.20 to 0.33. Most preferably Mg₆AL₂(OH)₁₆CO₃·4H₂O。

The Mg-Al series hydrotalcite compound can be prepared by the following method: adding carbonate or carbonate and caustic alkali to an aqueous solution of a water-soluble aluminum salt or aluminate selected from aluminum sulfate, aluminum acetate and alum and a water-soluble magnesium salt to maintain the pH of the reaction mixture at 8.0 or more, thereby carrying out the reaction. The obtained hydrotalcite-like compound is pulverized and classified to obtain hydrotalcite-like compound particles.

The particles of the hydrotalcite-like compound and the particles of an anion exchange resin (for example, Amberlite, which is an anion exchange resin commercially available from Organo corporation) can be granulated and classified to have a preferable particle size. As a granulation method, extrusion molding is usedThe granulation or the granulation by compression molding of (2) can easily produce a BET specific surface area of 500m²Particles of the total amount of the monomer (s)/g or less are preferred. Particularly, granulation by extrusion molding can produce a BET specific surface area of 100m²Particles of the total amount of the monomer (s)/g or less are preferred.

As described above, the particles contribute to an increase in filter hardness and an increase in filter ventilation resistance, and the filtration rate of the vapor phase component of mainstream smoke can be changed by changing the type and the amount of addition. For example, the low adsorption particles and the selective adsorption particles can be used in combination. In this case, the low-adsorbability particles do not substantially remove the entire vapor phase component of the mainstream smoke, and the selective-adsorbability particles contribute to selective removal of the stimulus component. This makes it possible to selectively remove the irritating component while maintaining the filtration characteristics of the membrane filter.

Alternatively, from the viewpoint of increasing the change in the flavor of the smoking article, the particles are nonselective adsorptive particles having no selectivity and having the ability to remove the entire vapor phase component of mainstream smoke from a wide range, for example, particles such as activated carbon, zeolite, alumina porous body, and silica gel, instead of the low adsorptive particles and the selective adsorptive particles described above. The activated carbon may be activated, pulverized, or classified using coconut shell, palm, or coal as a raw material. In this case, the BET specific surface area of the activated carbon is set to 1000 to 1800m²(ii) in terms of/g. Combining the tar low filtration properties of membrane filters with the high adsorption properties of the vapor phase component of non-selective adsorbent particles, unprecedented new flavors can be exhibited.

The filter of the present invention includes the filter medium having an air flow path and composed of a corrugated film, and the particles arranged in the air flow path, and further includes a wrapping paper around which the filter medium is wrapped. The winding paper used in general for the filter material for winding the cellulose acetate tow can be used.

As described above, the filter of the present invention includes a filter medium formed of a corrugated film and having an air flow passage, and particles disposed in the air flow passage. With this configuration, the filter of the present invention can reduce the filtration rate of the whole mainstream smoke components, and can achieve sufficient filter hardness and sufficient filter ventilation resistance. Thus, the smoking article provided with the filter of the present invention can provide a user with a feeling of gripping and gripping without discomfort, and can provide an appropriate inhalation resistance and an increased tobacco feeling (increased inhalation satisfaction).

The filter of the present invention preferably has a circumference of 16 to 26mm, and more preferably has a circumference of 24 to 26 mm. That is, the filter preferably has a diameter of 5.1 to 8.3mm, and more preferably 7.6 to 8.3 mm.

As a sufficient filter hardness, the filter may have a thickness of 2 to 10[ mm ]^＊10]The hardness of (2). In addition, the filter may have a length of 50 to 140mmH per 10mm as a sufficient filter ventilation resistance₂The ventilation resistance of O.

The filter hardness can be calculated by the following method: the filter hardness tester manufactured by Cerulean corporation was used to measure the area of a pressed surface of a 300g load of 113mm²The filter was pressed for 10 seconds under the condition that the shape was circular, and the amount of deformation at that time [ mm ] was measured](Δ D) is calculated from the measured value based on the following formula.

Hardness of filter tip [ mm ]^＊10]＝ΔD×10

Before measuring the hardness of the filter, the filter was left at a temperature of 22 ℃ and a humidity of 60% for 12 hours or more, and then measured.

Setting the hardness of the filter to 10mm^＊10]Hereinafter, the "hardness not too soft" is set so that the user feels a gripping feeling without a sense of discomfort, a mouth-gripping feeling without a sense of discomfort, and a chewing feeling without a sense of discomfort. In addition, the hardness of the filter is set to 10[ mm ]^＊10]Therefore, when the cigarette is lightly knocked and the ash is dropped during smoking, when the fire is pressed in the ashtray at the end of smoking to extinguish the fire, the deformation of the filter tip is not unexpectedly generated. In addition, the hardness of the filter is set to 2[ mm ]^＊10]In the above, the hardness is set to "not too hard", and the tipping paper pair for cigarette production can be used at high speed in the conventional cigarette production apparatusGluing and connecting the cigarette rod and the filter rod.

The filter ventilation resistance is measured according to the ISO standard method (ISO6565) using, for example, a filter ventilation resistance measuring instrument manufactured by Cerulean corporation. The filter ventilation resistance is the difference in air pressure between the 1 st end face and the 2 nd end face when air of a predetermined air flow rate (17.5cc/min) is caused to flow from one end face (the 1 st end face) to the other end face (the 2 nd end face) in a state where air cannot pass through the side face of the filter. Units are usually expressed in mmH₂And O represents. It is known that the relationship between the filter ventilation resistance and the filter length is generally proportional within the range of practical lengths (5 mm to 200mm in length), and if the length is doubled, the filter ventilation resistance is doubled.

By setting the filter ventilation resistance within the above range, it is possible to realize a suction resistance without discomfort when a user smokes a smoking article (e.g., a cigarette).

According to other aspects, the filter for a smoking article of the present invention comprises:

low filtration filter having a filter ventilation resistance of 90mmH₂A tar filtration rate of 40% or less in the case of O;

a plurality of particles disposed in the gaps of the low filtration medium; and

and a winding paper around which the low filtration medium is wound.

"Filter ventilation resistance 90mmH₂The tar filtration (%) in the case of O can be determined as follows. That is, the Tar filtration rate (E _ Tar) (unit%) in the filter is calculated by the following equation using the Tar production amount (Tar _0) of the cigarette not connected to the filter to be evaluated for the Tar filtration rate and the Tar production amount (Tar _1) of the cigarette connected to the filter.

E_tar[％]＝{(Tar_0-Tar_1)÷Tar_0}×100

Further, the tar transmittance (%) in the filter is represented by 100-E _ tar.

In order to measure the amount of tar, a piston type constant volume automatic smoking machine (RM 20/CS manufactured by Borgwald Co.) was used to smoke under conditions of a flow rate of 17.5 ml/sec, a smoking time of 2 seconds/time, and a smoking frequency of 1 time/minute. Nicotine and coarse tar in the smoke passed through the filter were collected by a glass fiber filter (cambridge filter), and the "nicotine amount" and the "moisture weight" were measured by a gas chromatograph (7890A, Agilent). The amount of tar was measured gravimetrically. The difference between the weight of the glass fiber filter before smoking and the weight of the glass fiber filter after smoking was defined as the weight of the crude tar, and the value obtained by subtracting the weight of nicotine and the weight of moisture from the weight of the crude tar was defined as the "tar amount".

Ventilation resistance of filter tip of 90mmH₂The low filtration filter having a tar filtration ratio of 40% or less in the case of O is, for example, the filter described above, that is, the following filter: the air conditioner has a cylindrical shape having a 1 st end surface, a 2 nd end surface and a side surface, and includes a corrugated film in which ridges and valleys are alternately arranged, the ridges and valleys extending from the 1 st end surface to the 2 nd end surface, and a plurality of air flow passages capable of allowing air to flow from the 1 st end surface to the 2 nd end surface are formed. In other words, the ventilation resistance in the filter is 90mmH₂The low-filtration filter medium having a tar filtration rate of 40% or less in the case of O is, for example, a filter medium in which corrugated films are gathered so as to have a plurality of air flow passages in the longitudinal direction and have a cylindrical shape as a whole.

In the conventional filter with a fiber-packed layer (i.e., acetate filter), the filter ventilation resistance was 90mmH₂The tar filtration rate in the case of O was about 55%. The filter of the present invention has the same ventilation resistance as that of the conventional filter with a fiber-packed layer, but can achieve a very low tar filtration rate as compared with the conventional filter with a fiber-packed layer. Thus, the present invention provides a smoking article having an excellent tobacco flavor while having an inhalation resistance without unpleasant feeling. Specifically, when the "low-adsorbability particles" described above are used as the particles, a smoking article having an increased tobacco flavor and a suction resistance without a feeling of discomfort can be realized. Alternatively, in the case of using the above-described "selectively adsorptive particles" as the particles, a smoking article having inhalation resistance without unpleasant feeling and increased tobacco flavor while suppressing irritation can be realized. Or in the process ofWhen the "nonselective adsorptive particles" are used as the particles, a smoking article having an inhalation resistance without unpleasant feeling and having an unprecedented new tobacco flavor can be realized.

2. Smoking article

According to a further aspect, there is provided a smoking article comprising a filter for a smoking article of the invention. Examples of the smoking article include combustion type smoking articles in which a tobacco filler is burned, such as cigarettes; a non-combustion heating type smoking article for heating a tobacco filler without burning the tobacco filler; or a non-heating type smoking article in which the flavor component of the tobacco filler is smoked without burning or heating the tobacco filler. Examples of the non-combustion heating type smoking article include a carbon heat source type aspirator in which a tobacco filler is heated by combustion heat of a carbon heat source (see, for example, WO 2006/073065); an electrically heated aspirator including an aspirator and a heating device for electrically heating the aspirator (see, for example, WO 2010/110226); or a liquid atomization type aspirator (see, for example, WO2015/046385) for atomizing by heating a liquid aerosol source containing a fragrance source. As an example of the non-heating type smoking article, there is a flavor extractor which includes a suction holder and a tobacco filler filled in a main flow path of the suction holder and extracts a flavor component of the tobacco filler (see, for example, WO 2010/095659).

The cigarette of the present invention comprises:

a filter for a smoking article of the present invention;

a tobacco rod containing a tobacco filler and connected to one end of the filter; and

and a tipping paper wrapped around the filter and the tobacco rod so as to connect the filter and the tobacco rod.

As described above, since the smoking article of the present invention includes the filter of the present invention, it is possible to provide a gripping feeling without discomfort, a chewing feeling without discomfort, and a chewing feeling without discomfort to the user, and to provide an appropriate inhalation resistance and an increased tobacco feeling.

3. Method for manufacturing filter for smoking article

The method for manufacturing a filter for a smoking article of the present invention comprises:

adding a plurality of particles to the corrugated film;

collecting the corrugated film so as to have a plurality of air flow paths in a longitudinal direction and to form a filter material in which the corrugated film is integrally formed in a cylindrical shape, thereby disposing the particles in the air flow paths; and

and a step of wrapping the filter medium with a wound roll to obtain a filter.

The method can be carried out using a known filter rod manufacturing apparatus, and can be carried out using, for example, an apparatus described in Japanese patent application laid-open No. 1-243979 or Japanese patent application laid-open No. 9-294577.

The method may also include: and a step of sizing the overlapped part of the winding paper after the filter material is wound on the winding paper.

In addition, this method may include a step of spraying a liquid additive (i.e., a liquid adhesive) containing a binder such as an adhesive and a plasticizer on the corrugated film after the step of adding the plurality of particles to the corrugated film. Specifically, this method may include a step of applying a liquid additive containing a binder such as an adhesive or a plasticizer to the surface of the corrugated film and the surface of the particles by spraying or the like, between a step of adding a plurality of particles to the corrugated film and a step of forming a filter medium by collecting the corrugated film so as to have a plurality of air flow paths in the longitudinal direction and to form a cylindrical shape as a whole. Alternatively, the method may include a step of applying a liquid additive containing a binder such as an adhesive and a plasticizer to the surface of the corrugated film by spraying or the like, before the step of adding the plurality of particles to the corrugated film. The step of applying the adhesive is included, whereby the particles can be reliably held in the air flow path.

In addition, the method may further include a step of heating the obtained filter after the step of wrapping the filter medium with the wrapping paper to obtain the filter. Specifically, after the step of wrapping the filter medium with the wound roll of paper to obtain the filter, the filter obtained by wrapping the filter medium with the wound roll of paper may be subjected to any of a step of placing the filter in a treatment vessel having a high ambient temperature for a predetermined time, a step of heating the filter with a microgrid, and a step of heating the filter with hot air. By including any of these steps, when the liquid additive containing a binder is added, drying of the liquid additive containing a binder can be promoted, and when the liquid additive containing a binder is not added, the surface of the film is locally melted to increase the bonding area between the particles and the film, thereby reliably holding the particles.

In addition, the method may further include, before the step of adding the plurality of particles to the corrugated film, a step of heating the corrugated film in advance to moderately half-melt the surface of the corrugated film. Specifically, the surface of the film can be moderately semi-melted by heating the film while shaping the film into a wave shape by heating a pair of metal creping rolls that impart a wave shape to the film in advance. This increases the area of adhesion between the added particles and the film, and the particles can be reliably held.

4. Multi-section filter tip

The filter for a smoking article of the present invention may be used in the form of a conventional filter (i.e. a single filter) or in the form of a filter segment of a multi-segment filter. In the case where the filter of the present invention is used in the form of a filter segment of a multi-segment filter, the remaining filter segments may be aligned in the longitudinal direction with the filter of the present invention to form a multi-segment filter. As the remaining filter segments, for example, a filter comprising a normal cellulose acetate fiber filling layer, a hollow paper tube containing no filter material, a molded body made of plastic or metal, or the like can be used.

The selection of filter segments for use in combination with the filters of the present invention, the order of upstream and downstream placement, may be determined for various purposes. For example, in order to prevent a smoker who is accustomed to the appearance of a conventional filter containing a cellulose acetate filler from feeling uncomfortable with the appearance of the mouth-end face of the filter, the filter of the present invention may be disposed as an upstream segment and a downstream segment containing a cellulose acetate filler. Thus, the effect obtained by the filter of the present invention can be achieved, and the smoker can not feel uncomfortable feeling of the mouth-end face appearance. Furthermore, by using a filter segment comprising a member having a flavour-releasing function (e.g. flavour particles) in combination with the filter of the present invention, the variation in flavour of the smoking article can be extended.

In the case of a multi-segment filter, the length of each filter segment may be selected as appropriate for the purpose, and the number of filter segments may also be selected as appropriate for the purpose. Filters combining 2 segments are generally referred to as dual filters and filters combining 3 segments are generally referred to as triple filters. As a method for producing a multi-segment filter, for example, a multi-segment filter can be produced by making each filter segment, cutting the segment into a predetermined length, and wrapping the filter segment with an outer filter wrapping paper.

5. Preferred mode of carrying out the invention

Preferred embodiments are summarized below.

[1] A filter for a smoking article comprising:

a filter medium having a columnar shape including a 1 st end surface, a 2 nd end surface, and a side surface, and including a corrugated film in which ridge portions and valley portions are alternately arranged, the ridge portions and the valley portions extending from the 1 st end surface to the 2 nd end surface, and a plurality of air flow passages capable of allowing air to flow from the 1 st end surface to the 2 nd end surface are formed;

a plurality of particles disposed in the air flow path; and

and a winding paper for winding the filter medium so as to cover the side surface.

[2] A filter for a smoking article comprising:

a filter medium formed by collecting a corrugated film so as to have a plurality of air flow passages in a longitudinal direction and to have a cylindrical shape as a whole;

a plurality of particles disposed in the air flow path; and

and a winding paper 4 around which the filter medium is wound.

[3] The filter for a smoking article according to [1] or [2], wherein,

the corrugated film is a film formed from a molten film material.

[4] The filter for smoking articles according to [3], wherein,

the corrugated film is a film through which air does not substantially permeate.

[5] The filter for smoking articles according to any one of [1] to [4], wherein,

the corrugated film has a thickness of 30 to 200 μm, preferably 30 to 100 μm.

[6] The filter for smoking articles according to any one of [1] to [5],

the corrugated film has a tensile elongation of 100% or more, preferably 100% to 1000%, and more preferably 150% to 800%.

[7] The filter for smoking articles according to any one of [1] to [6],

the corrugated film has a wave pitch of 0.5mm to 1.5mm, preferably 0.5mm to 1.0 mm.

[8] The filter for a smoking article according to any one of [1] to [7], which contains the wavy film at a filling rate of 10 to 40%, preferably at a filling rate of 20 to 40%.

[9] The filter for smoking articles according to any one of [1] to [8],

the particles have a particle size of 10 to 70 mesh, preferably 12 to 70 mesh, more preferably 10 to 42 mesh, in accordance with JIS Z8801-1 (2006).

[10] The filter for smoking articles according to any one of [1] to [9],

the particles are contained in an amount of 20 to 100mg, preferably 20 to 60mg, more preferably 20 to 50mg per 10mm length when the circumference of the filter is 24.0 mm.

[11] The filter for smoking articles according to any one of [1] to [10],

the filter for smoking articles has a circumference of 16 to 26mm, preferably 24 to 26 mm.

[12] The filter for smoking articles according to any one of [1] to [10],

the filter for smoking articles has a diameter of 5.1 to 8.3mm, preferably 7.6 to 8.3 mm.

[13] The filter for smoking articles according to any one of [1] to [12],

the corrugated film is a high molecular polymer film.

[14] The filter for smoking articles according to any one of [1] to [13],

the corrugated film is a plastic film.

[15] The filter for smoking articles according to any one of [1] to [14], wherein,

the corrugated film is a polyolefin film or a polyester film.

[16] The filter for smoking articles according to any one of [1] to [15], wherein,

the film is selected from polypropylene film, polybutylene succinate/adipate film, polyethylene film, polyvinyl chloride film, polyethylene terephthalate film, polylactic acid film, cellulose acetate film, and film formed by more than 2 kinds of materials constituting the films.

[17] The filter for smoking articles according to any one of [1] to [16],

the corrugated membrane is a biodegradable membrane.

[18] The filter for smoking articles according to any one of [1] to [17],

the particles have a particle size of 1 to 500m²A BET specific surface area of 1 to 100m²BET specific surface area in g.

[19] The filter for smoking articles according to any one of [1] to [18], wherein,

the particles are selected from the group consisting of cellulose particles, cellulose acetate particles, calcium carbonate particles, activated carbon particles having a low degree of activation, unactivated carbon particles, and combinations thereof.

[20] The filter for smoking articles according to any one of [1] to [19],

the particles are selected from the group consisting of hydrotalcite-like compound particles and anion exchange resin particles.

[21] The filter for smoking articles according to any one of [1] to [20], wherein,

the particles are particles of a hydrotalcite-like compound represented by the following general formula,

[M²⁺ _1-xM³⁺ _x(OH)₂][(A^n-)_x/n·mH₂O]

here, M²⁺Is a 2-valent metal ion selected from Mg, Zn, Ni and Ca, M³⁺Is Al ion, A^n-Is selected from CO₃、SO₄、OOC-COO、Cl、Br、F、NO₃、Fe(CN)₆ ^3-、Fe(CN)₆ ^4-N-valent anions in 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 sulfonic acid, wherein x is more than 0.1 and less than 0.4, and m is more than 0 and less than 2.

[22] The filter for smoking articles according to [21], wherein,

in the above formula, M²⁺Is Mg ion, M³⁺Is Al ion, A^n-Is CO₃ ^2-Or SO₄ ^2-X is more than 0.1 and less than 0.4, and m is more than 0 and less than 2.

[23] The filter for smoking articles according to [22], wherein,

in the above formula, x is in the range of 0.20 to 0.33.

[24] The filter for smoking articles according to [21], wherein,

the above general formula is Mg₆AL₂(OH)₁₆CO₃·4H₂O。

[25] The filter for smoking articles according to any one of [1] to [24],

the particles are selected from the group consisting of activated carbon, zeolite, alumina porous body, silica gel, and combinations of these particles.

[26] The filter for smoking articles according to any one of [1] to [18], wherein,

the particle is a combination of the particle described in [19] and the particle described in any one of [20] to [24 ].

[27] The filter for a smoking article according to any one of [1] to [26],

the particles are arranged in the air flow path with a binder.

[28] The filter for smoking articles according to [27], wherein,

the adhesive is an adhesive or a plasticizer.

[29] The filter for smoking articles according to any one of [1] to [28],

the filter for smoking articles has an average length of 50-140 mmH per 10mm₂The ventilation resistance of O.

[30] The filter for smoking articles according to any one of [1] to [29],

the filter for smoking article has a thickness of 2-10 mm^＊A hardness of 10.

[31] A filter for a smoking article comprising:

low filtration filter having a filter ventilation resistance of 90mmH₂A tar filtration rate of 40% or less in the case of O;

a plurality of particles disposed in the gaps of the low filtration medium; and

and a winding paper around which the low filtration medium is wound.

[32] The filter for smoking articles according to [31], wherein,

the low-filtration filter medium has a columnar shape having a 1 st end surface, a 2 nd end surface, and a side surface, and includes a corrugated film in which ridge portions and valley portions are alternately arranged, the ridge portions and the valley portions extending from the 1 st end surface to the 2 nd end surface, and a plurality of air flow passages capable of allowing air to flow from the 1 st end surface to the 2 nd end surface are formed.

[33] The filter for smoking articles according to [31], wherein,

the low filtration filter is formed by collecting a corrugated film so as to have a plurality of air flow passages in the longitudinal direction and to have a cylindrical shape as a whole.

[34] A smoking article comprising the filter for a smoking article according to any one of [1] to [33 ].

[35] The smoking article according to [34], wherein,

the smoking article is a combustion type smoking article in which a tobacco filler is combusted.

[36] The smoking article according to [34], wherein,

the smoking article is a non-combustion heating type smoking article in which a tobacco filler is heated without being combusted.

[37] The smoking article as claimed in [36], wherein,

the non-combustion heating type smoking article is a carbon heat source type aspirator for heating the tobacco filler by the combustion heat of the carbon heat source, an electric heating type aspirator having an aspirator and a heating device for electrically heating the aspirator, or a liquid atomizing type aspirator for atomizing a liquid aerosol source containing a flavor source by heating.

[38] The smoking article according to [34], wherein,

the smoking article is a non-heating type smoking article which does not burn or heat the tobacco filler and sucks the flavor component of the tobacco filler.

[39] The smoking article according to [38], wherein,

the non-heating type smoking article comprises a suction holder and a tobacco filler filled in a main flow path of the suction holder, and is a flavor aspirator for extracting flavor components of the tobacco filler.

[40] A cigarette, comprising:

[1] the filter for a smoking article according to any one of [33] to [33 ];

a tobacco rod containing a tobacco filler and connected to one end of the filter; and

and a tipping paper wrapped around the filter and the tobacco rod so as to connect the filter and the tobacco rod.

[41] A method of manufacturing a filter for a smoking article comprising:

adding a plurality of particles to the corrugated film;

collecting the corrugated film so as to have a plurality of air flow paths in a longitudinal direction and to form a filter material in which the corrugated film is integrally formed in a cylindrical shape, thereby disposing the particles in the air flow paths; and

and a step of wrapping the filter medium with a wound roll to obtain a filter.

[42] The method according to [41], wherein,

the filter for a smoking article according to any one of [1] to [33 ].

[43] The method according to [41] or [42], further comprising a step of sizing a lap portion of the wrapping paper after the step of wrapping the filter medium with the wrapping paper to obtain a filter.

[44] The method according to any one of [41] to [43], further comprising a step of spraying a liquid adhesive on the corrugated film after the step of adding the plurality of particles to the corrugated film.

[45] The method according to any one of [41] to [43], further comprising a step of spraying a liquid adhesive on the corrugated film, prior to the step of adding the plurality of particles to the corrugated film.

[46] The method according to [44] or [45], wherein,

the liquid adhesive contains a binder or a plasticizer as an adhesive.

[47] The method according to any one of [41] to [46], further comprising a step of heating the filter after the step of wrapping the filter medium with the wrapping paper to obtain a filter.

[48] The method according to any one of [41] to [46], further comprising a step of heating the filter medium before the step of wrapping the filter medium with the wrapping paper to obtain a filter.

[49] The method according to any one of [41] to [46], further comprising a step of heating the corrugated film before the step of adding the plurality of particles to the corrugated film.