SMOKING COMPOSITION SHEET

Abstract

 A smoking composition sheet having an air permeability of more than 0 CORESTA Unit and containing a humectant, a binder, and either or both of a flavoring agent and a forming aid.

Description

TECHNICAL FIELD

[0001] The present invention relates to a smoking composition sheet.

BACKGROUND ART

[0002] For designing a smoking article that meets the preference of users, it is important to control the profile of component release from a smoking composition. In recent years, there have been proposed numerous techniques concerning non-combustion smoking articles for inhaling components generated through heating of a tobacco sheet (Patent Literature (PTL) 1, for example). In such a non-combustion smoking article, the control of the profile is emphasized particularly.

CITATION LIST

PATENT LITERATURE

[0003] PTL 1: Japanese Patent No. 5292410

SUMMARY OF INVENTION

TECHNICAL PROBLEM

[0004] Conventional smoking composition sheets have zero or extremely low air permeability. To control the component release from such a composition sheet, for example, forming the sheet into a roll has been performed to change the amount of the composition filled or to change the density of the composition. However, such a conventional method has a drawback of a narrow applicable range in product design since there exists the limit to the amount filled or the density in order to retain the rolled shape. In view of this, the object of the present invention is to provide a smoking composition sheet that attains an excellent profile.

SOLUTION TO PROBLEM

[0005] The present inventors have resolved the above-mentioned problems by setting the air permeability of a smoking composition sheet to a particular range. In other words, the object is achieved by the present invention below.

(1) A smoking composition sheet having an air permeability of more than 0 CORESTA Unit (CU) and containing:

a humectant;

a binder; and

either or both of a flavoring agent and a forming aid.

(2) The sheet according to (1), having the air permeability of 500 CU or more.

(3) The sheet according to (1) or (2), where the flavoring agent is selected from the group consisting of tobacco, flavors, and combinations thereof.

(4) The sheet according to any of (1) to (3), where the humectant is a polyhydric alcohol.

(5) The sheet according to any of (1) to (4), where the binder is selected from the group consisting of polysaccharides, proteins, synthetic polymers, and combinations thereof.

(6) The sheet according to any of (1) to (5), where the forming aid is pulp or a nonwoven fabric of plant fibers or synthetic fibers.

(7) The sheet according to any of (1) to (6), being a pressure-formed sheet.

(8) The sheet according to any of (1) to (6), having a plurality of holes formed through physical processing.

(9) The sheet according to any of (1) to (7), having a plurality of holes formed through chemical processing.

ADVANTAGEOUS EFFECTS OF INVENTION

[0006] According to the present invention, it is possible to provide a smoking composition sheet that attains an excellent profile.

BRIEF DESCRIPTION OF DRAWINGS

[0007] 

Fig. 1 is a schematic view of exemplary smoking segments using a smoking composition sheet.

Fig. 2 is a schematic cross-sectional view of an exemplary heat-not-burn smoking system.

Fig. 3 is a schematic cross-sectional view of an exemplary heat-not-burn flavor inhaler article.

Fig. 4 shows the results of smoking tests.

DESCRIPTION OF EMBODIMENTS

[0008] Hereinafter, the present invention will be described in detail. In the present invention, the expression of "X to Y" includes the lower and the upper limits of X and Y.

1. Smoking Composition Sheet

[0009] A smoking composition sheet is a sheet to be used for a smoking article and contains a humectant, a binder, and either or both of a flavoring agent and a forming aid.

(1) Humectants

[0010] A smoking composition sheet contains a humectant. A humectant is a material for providing moisture to a smoking composition sheet as well as a material that generates an aerosol through vaporization upon heating and subsequent cooling or that generates an aerosol through atomization. Any common humectant may be used, and examples include those having a boiling point above 100°C, polyhydric alcohols such as glycerol, propylene glycol (PG), and triethyl citrate (TEC), and triacetin. The amount of humectant in a smoking composition sheet is preferably 1 to 40 weight% and more preferably 10 to 20 weight% on dry weight basis (weight after removing water contained, the same applies hereinafter). When the amount of humectant exceeds the upper limit, the production of smoking composition sheets could become difficult. Meanwhile, when the amount is less than the lower limit, smoky feeling could deteriorate.

(2) Binders

[0011] A binder is an adhesive for binding components that constitute a smoking composition sheet. In the present invention, any common binder may be used. Examples of such binders include polysaccharides, such as guar gum and xanthan gum, and cellulose derivatives, such as CMC (carboxymethyl cellulose), CMC-Na (carboxymethyl cellulose sodium salt), and HPC (hydroxypropyl cellulose). The upper limit for the binder content is preferably 6 weight% or less on dry weight basis (weight after removing water contained, the same applies hereinafter) relative to the dry weight of a smoking composition sheet. Meanwhile, the lower limit is preferably 1 weight% or more and more preferably 3 weight% or more. When the amount of binder exceeds the upper limit or is less than the lower limit, the above-mentioned effect could not be exerted satisfactorily.

[0012] Exemplary binders include polysaccharides, proteins, and synthetic polymers. Hereinafter, concrete examples of these binders will be described. In the present invention, these binders may also be used in combination.

1) Polysaccharides

1-1) Cellulose Derivatives

[0013] 

[Cellulose Ethers]
Methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxymethyl ethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, benzyl cellulose, trityl cellulose, cyanoethyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, aminoethyl cellulose

[Cellulose Esters]

Organic acid esters: cellulose acetate, cellulose formate, cellulose propionate, cellulose butyrate, cellulose benzoate, cellulose phthalate, tosyl cellulose

Inorganic acid esters: cellulose nitrate, cellulose sulfate, cellulose phosphate, cellulose xanthate

1-2) Naturally Occurring Polysaccharides

[0014] 

[Plant-derived]
Guar gum, tara gum, locust bean gum, tamarind seed gum, pectin, gum arabic, gum tragacanth, gum karaya, gum ghatti, arabinogalactan, flaxseed gum, cassia gum, psyllium seed gum, artemisia seed gum

[Algae-derived]
Carrageenan, agar, alginic acid, propylene glycol alginate, furcellaran, Gloiopeltis furcata extract

[Microorganism-derived]
Xanthan gum, gellan gum, curdlan, pullulan, Agrobacterium succinoglycan, welan gum, Macrophomopsis gum, rhamsan gum

[Crustacea-derived]
Chitin, chitosan, glucosamine

[Starch Derivatives]
Starch, sodium starch glycolate, pregelatinized starch, dextrin

2) Proteins

[0015] Wheat gluten, rye gluten

3) Synthetic polymers

[0016] Polyphosphoric acid, sodium polyacrylate, polyvinylpyrrolidone

(3) Flavoring Agents

[0017] A flavoring agent is a material that provides aroma and taste and is preferably selected from the group consisting of tobacco, flavors, and combinations thereof. Examples of tobacco include shreds of dry tobacco leaves and pulverized leaf tobacco. Pulverized leaf tobacco refers to particles obtained through pulverization of leaf tobacco. Such pulverized leaf tobacco may have the particle size D90 set to 20 to 1000 µm, for example, and preferably 50 to 500 µm. Moreover, the average particle size D50 may be set to preferably 20 to 1000 µm and more preferably 50 to 500 µm. Pulverization may be performed using a common grinding mill as either dry grinding or wet grinding. The resulting pulverized leaf tobacco is thus referred to as leaf tobacco particles as well. In the present invention, the particle size is obtained by a laser diffraction/scattering method and is concretely measured using a laser diffraction particle size analyzer (LA-950 from Horiba, Ltd., for example). Further, the type of tobacco is not limited, and flue-cured, burley, oriental, and domestic may be used, and others such as Nicotiana tabacum varieties or Nicotiana rustic a varieties, for example, may be used. The amount of tobacco in a smoking composition sheet is not particularly limited but is preferably 50 to 95 weight% and more preferably 60 to 90 weight% on dry weight basis. A smoking composition sheet, when containing a flavoring agent, need not contain a forming aid described hereinafter.

[0018] A flavor is a substance that provides aroma or taste. Such a flavor may be a natural flavor or a synthetic flavor and may be a solid or a liquid. One flavor or a mixture of a plurality of flavors may be used. Any flavor commonly used for smoking articles may be used, and concrete examples will be described hereinafter. A flavor may be incorporated into a sheet for a smoking article in an amount such that the smoking article can provide preferable aroma or taste. For example, the amount in a smoking composition sheet is preferably 1 to 30 weight% and more preferably 2 to 20 weight%.

[0019] From a viewpoint of imparting satisfactorily perceived flavor, exemplary flavors include, but are not particularly limited to, acetanisole, acetophenone, acetylpyrazine, 2-acetylthiazole, alfalfa extract, amyl alcohol, amyl butyrate, trans-anethole, star anise oil, apple juice, Peru balsam oil, beeswax absolute, benzaldehyde, benzoin resinoid, benzyl alcohol, benzyl benzoate, benzyl phenylacetate, benzyl propionate, 2,3-butanedione, 2-butanol, butyl butyrate, butyric acid, caramel, cardamom oil, carob absolute, β-carotene, carrot juice, L-carvone, β-caryophyllene, cassia bark oil, cedarwood oil, celery seed oil, chamomile oil, cinnamaldehyde, cinnamic acid, cinnamyl alcohol, cinnamyl cinnamate, citronella oil, DL-citronellol, clary sage extract, cocoa, coffee, cognac oil, coriander oil, cuminaldehyde, davana oil, δ-decalactone, γ-decalactone, decanoic acid, dill oil, 3,4-dimethyl-1,2-cyclopentanedione, 4,5-dimethyl-3-hydroxy-2,5-dihydrofuran-2-one, 3,7-dimethyl-6-octenoic acid, 2,3-dimethylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, ethyl 2-methylbutyrate, ethyl acetate, ethyl butyrate, ethyl hexanoate, ethyl isovalerate, ethyl lactate, ethyl laurate, ethyl levulinate, ethyl maltol, ethyl octanoate, ethyl oleate, ethyl palmitate, ethyl phenylacetate, ethyl propionate, ethyl stearate, ethyl valerate, ethyl vanillin, ethyl vanillin glucoside, 2-ethyl-3,(5 or 6)-dimethylpyrazine, 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone, 2-ethyl-3-methylpyrazine, eucalyptol, fenugreek absolute, genet absolute, gentian root infusion, geraniol, geranyl acetate, grape juice, guaiacol, guava extract, γ-heptalactone, γ-hexalactone, hexanoic acid, cis-3-hexen-1-ol, hexyl acetate, hexyl alcohol, hexyl phenylacetate, honey, 4-hydroxy-3-pentenoic acid γ-lactone, 4-hydroxy-4-(3-hydroxy-1-butenyl)-3,5,5-trimethyl-2-cyclohexen-1-one, 4-(p-hydroxyphenyl)-2-butanone, 4-hydroxyundecanoic acid sodium salt, immortelle absolute, β-ionone, isoamyl acetate, isoamyl butyrate, isoamyl phenylacetate, isobutyl acetate, isobutyl phenylacetate, jasmine absolute, kola nut tincture, labdanum oil, terpeneless lemon oil, licorice extract, linalool, linalyl acetate, lovage root oil, maltol, maple syrup, menthol, menthone, L-menthyl acetate, p-methoxybenzaldehyde, methyl 2-pyrrolyl ketone, methyl anthranilate, methyl phenylacetate, methyl salicylate, 4'-methylacetophenone, methyl cyclopentenolone, 3-methylvaleric acid, mimosa absolute, molasses, myristic acid, nerol, nerolidol, γ-nonalactone, nutmeg oil, δ-octalactone, octanal, octanoic acid, orange flower oil, orange oil, oris root oil, palmitic acid, ω-pentadecalactone, peppermint oil, petitgrain Paraguay oil, phenethyl alcohol, phenethyl phenylacetate, phenylacetic acid, piperonal, plum extract, propenylguaethol, propyl acetate, 3-propylidenephthalide, prune juice, pyruvic acid, raisin extract, rose oil, rum, sage oil, sandalwood oil, spearmint oil, styrax absolute, marigold oil, tea distillate, α-terpineol, terpinyl acetate, 5,6,7,8-tetrahydroquinoxaline, 1,5,5,9-tetramethyl-13-oxatricyclo[8.3.0.0.(4.9)]tridecane, 2,3,5,6-tetramethylpyrazine, thyme oil, tomato extract, 2-tridecanone, triethyl citrate, 4-(2,6,6-trimethylcyclohex-1-enyl)but-2-en-4-one, 2,6,6-trimethylcyclohex-2-ene-1,4-dione, 4-(2,6,6-trimethylcyclohexa-1,3-dienyl)but-2-en-4-one, 2,3,5-trimethylpyrazine, γ-undecalactone, γ-valerolactone, vanilla extract, vanillin, veratraldehyde, violet leaf absolute, N-ethyl-p-menthane-3-carboxamide (WS-3), ethyl 2-(p-menthane-3-carboxamido)acetate (WS-5), sugars (sucrose, fructose, and so forth), cocoa powder, carob powder, coriander powder, licorice powder, orange peel powder, rose hip powder, chamomile flower powder, lemon verbena powder, peppermint powder, leaf powder, spearmint powder, black tea powder, natural plant flavors (jasmine oil, lemon oil, vetiver oil, lovage oil, for example), esters (menthyl acetate, isoamyl propionate, for example), and alcohols (phenethyl alcohol, cis-6-nonen-1-ol, for example). These flavors may be used alone or in combination of two or more.

(4) Forming Aids

[0020] A smoking composition sheet contains a forming aid. A forming aid is a material added for facilitating the formation of a smoking composition sheet. Exemplary forming aids include pulp and nonwoven fabrics of plant fibers or synthetic fibers, and further concrete examples include fibers derived from tobacco and fibers derived from materials other than tobacco. The amount of forming aid to be added is preferably 0.5 to 2.0 weight% in a smoking composition sheet. A smoking composition sheet may contain either of a flavoring agent and a forming aid. Specifically, a sheet containing a forming aid can effectively ensure the strength and lower the tackiness, for example. Moreover, a sheet containing both thereof, for example, can effectively enhance the holding ability of a flavor and so forth since the flavor and so forth can be supported on a forming aid.

(5) Emulsifiers

[0021] A smoking composition sheet may contain an emulsifier. An emulsifier enhances affinity between a humectant, which is lipophilic, and a flavoring agent, which is hydrophilic. For this reason, the addition of an emulsifier is effective particularly when a lipophilic humectant is used. Any common emulsifier may be used, and examples include emulsifiers having HLB of 8 to 18. The amount of emulsifier is not particularly limited but is preferably 0.1 to 3 parts by weight and more preferably 1 to 2 parts by weight on dry weight basis relative to 100 parts by weight of a smoking composition sheet.

(6) Characteristics and Forms of Smoking Composition Sheet

1) Air Permeability

[0022] A smoking composition sheet has an air permeability of more than 0 CORESTA Unit (CU), preferably 50 CU or more, 100 CU or more, 200 CU or more, 300 CU or more, or 400 CU or more, and further preferably 500 CU or more. The upper limit is not limited but is preferably 20,000 CU or less and more preferably 15,000 CU or less. The CORESTA Unit is a flow rate of air (cm³) per 1 cm² for 1 minute at a pressure difference of 1 kPa. The air permeability can be measured using a permeability unit PPM 1000M from Cerulean. In the present invention, the air permeability is preferably measured through the following procedure. 1) A sheet is conditioned by leaving at room temperature of 22°C and a relative humidity of 60% for 48 hours. 2) Subsequently, the sheet is cut into the size of 40 mm × 240 mm, and a flow rate of air from the front to the rear surface is measured using a permeability unit (PPM 1000M from Cerulean) set to a pressure difference of 1 kPa and a circular measuring head of 2 cm². 3) The measurement environment is set to room temperature (22°C, for example) and 60% relative humidity.

[0023] The present invention can attain a desirable profile since a smoking composition sheet having a particular air permeability is used. Specifically, it is possible to attain a profile that achieves high delivery at initial puffs as compared with a conventional sheet and that is less likely to lower the amount delivered at later puffs in the same manner as a conventional sheet. The reason is not limited but is presumably because the release efficiency of a humectant from the sheet increases due to the high air permeability of the sheet, thereby increasing the amount of aerosol formed from the humectant.

2) Thickness

[0024] The thickness of a smoking composition sheet is not limited but is preferably 20 to 2000 µm, more preferably 100 to 1500 µm, and further preferably 100 to 1000 µm in an embodiment.

3) Density

[0025] A smoking composition sheet has a density of preferably 0.5 to 2.0 g/cm³ and more preferably 0.5 to 1.0 g/cm³. As described hereinafter, a smoking composition sheet preferably has physically or chemically formed holes. The density herein is a density for the entire sheet including such holes but not a density for the part excluding hole portions. Further, when a smoking composition sheet has a density of 1.0 g/cm³ or less, it is possible to attain the delivery of further sufficient flavor components at the beginning of inhalation.

4) Holes

[0026] As mentioned above, a smoking composition sheet preferably has holes formed through processing. Such holes can be formed through physical processing or chemical processing. Examples of the former include laser processing, cutting using a needle or the like, and electric perforation through local discharge. Examples of the latter include etching. The shape of a hole is not limited and may be circular, elliptic, or polygonal, for example. Moreover, the holes are preferably penetrating holes. The size, number, and arrangement of the holes are adjusted appropriately to attain a desirable air permeability. In an embodiment, the holes have a size of 0.1 to 0.8 mm as the diameter of the circumscribed circle. Further, the holes are arranged, in an embodiment, as a lattice on the sheet at the shortest distance between the neighboring holes of about 0.2 to 0.8 mm.

(7) Smoking Segment

[0027] A smoking segment used for a smoking article can be produced from a smoking composition sheet. The smoking segment includes, in an embodiment, a tubular wrapper and a smoking composition sheet spirally rolled and packed within the wrapper (see Fig. 1 (A)). In the figure, 20A is a smoking segment, 1 is a smoking composition sheet, and 22 is a wrapper, which is typically paper. The segment preferably has a rod shape, and the length may be set to about 15 to 80 mm and the diameter to about 5 to 10 mm. Further, the smoking segment 20A in Fig. 1 (A) may also be cut to have an aspect ratio (length/diameter) of about 0.5 to 1.2 (see Fig. 1 (B)).

[0028] The smoking segment 20A includes, in another embodiment, a tubular wrapper 22 and a smoking composition sheet 1 folded and packed within the wrapper. The ridges formed through folding extend almost parallel to the longitudinal direction of the segment (see Fig. 1 (C)). The smoking segment 20A preferably has a rod shape, and the length may be set to about 15 to 80 mm and the diameter to about 5 to 10 mm. In this embodiment, the smoking composition sheet 1 has preferably been processed in advance by surface creasing, such as pleating or crimping.

[0029] The smoking segment 20A includes, in another embodiment, a tubular wrapper 22 and a cut piece 1c of a smoking composition sheet, which is packed within the wrapper (see Fig. 1 (D)). The smoking segment 20A preferably has a rod shape, and the length may be set to about 15 to 80 mm and the diameter to about 5 to 10 mm. The size of a cut piece is not limited, but the length of the longest side may be set to about 2 to 20 mm and the width to about 0.5 to 1.5 mm, for example.

[0030] The smoking segment 20A includes, in another embodiment, a tubular wrapper 22 and strand-type shreds packed within the wrapper (see Fig. 1 (E)). Such strand-type shreds are packed with the longitudinal direction almost parallel to the longitudinal direction of the wrapper 22. The width of a strand-type shred may be set to about 0.5 to 1.5 mm.

[0031] The smoking segment 20A includes, in another embodiment, a tubular wrapper 22 and tobacco shred filler randomly packed within the wrapper. Tobacco shreds are shredded products and thus differ from strand-type shreds.

2. Production Method

[0032] A smoking composition sheet can be produced by any method but is preferably produced by a method including the following steps of:

step 1 of preparing a mixture by kneading at least a humectant, a binder, either or both of a flavoring agent and a forming aid, and a medium;

step 2 of preparing a wet sheet by rolling the mixture or extruding the mixture from a die; and

step 3 of drying the wet sheet.

[0033] A sheet formed as above under applied pressure is referred to as "pressure-formed sheet," and such "pressure-formed sheets" encompass a "laminate sheet" and an "extruded sheet" as described hereinafter. A laminate sheet is a sheet obtained by rolling a mixture once or more using a roller into a target thickness, followed by drying to a target water content. An extruded sheet is a sheet obtained by extruding a mixture from a T die or the like at a target thickness, followed by drying to a target water content. A pressure-formed sheet may be produced by rolling and extrusion in combination. For example, a mixture may be formed into a sheet through extrusion, further followed by rolling.

(1) Step 1

[0034] In this step, at least a humectant, a binder, either or both of a flavoring agent and a forming aid, and a medium are kneaded. An emulsifier may also be added as necessary. The amounts of the respective components to be added are adjusted to attain the above-mentioned amounts. The medium preferably primarily contains, for example, water or a water-soluble organic solvent having a boiling point below 100°C, such as ethanol, and is more preferably water or ethanol.

[0035] This step can be performed by kneading the respective components but is preferably performed through 1) pulverization of a raw material (classified leaf tobacco, for example), 2) preparation of a wet powder, and 3) kneading.

1) Pulverization

[0036] A raw material is preferably coarsely crushed, followed by fine grinding using a grinding mill (ACM-5 from Hosokawa Micron Corporation, for example). The particle size D90 after fine grinding is preferably 20 to 1000 µm. The particle size is measured using a laser diffraction particle size analyzer, such as Mastersizer (from Malvern Panalytical Ltd.).

2) Preparation of Wet Powder

[0037] A binder and either or both of a flavoring agent and a forming aid are added, as necessary, with a lipid or other additives and mixed. Since the mixing is preferably dry blending, a mixer is preferably used as a mixing apparatus. It is preferable to use a pulverized tobacco raw material (leaf tobacco particles, for example) as a flavoring agent. Subsequently, the resulting dry blend is added with water or another medium and a humectant and mixed using a mixer to prepare a wet powder (powder in the wet state). The amount of medium in the wet powder may be set to 20 to 80 weight% and preferably 20 to 40 weight% and is appropriately adjusted by step 2. For example, the amount of medium may be set to 20 to 50 weight% in the case of performing rolling in step 2 and to 20 to 80 weight% in the case of performing extrusion. The solid concentration of a wet powder is preferably 50 to 90 weight%.

3) Kneading

[0038] The wet powder is kneaded using a kneader (DG-1 from Dalton Corporation, for example). The kneading is preferably performed until the medium permeates through the entire powder. For example, kneading is preferably performed until a mixture becomes uniform in color under visual observation.

(2) Step 2

[0039] In this step, a wet sheet is prepared by rolling the mixture (wet powder) or extruding the mixture from a die. For example, the mixture is sandwiched between two substrate films and rolled into a predetermined thickness (over 100 µm) by passing through a pair of rollers using a calendaring machine (from Yuri Roll Machine Co., Ltd., for example), thereby obtaining a laminate in which a wet sheet exists between two substrate films. The substrate films are preferably non-adhesive films, such as fluoropolymer films. Such rolling using rollers may be performed a plurality of times. Further, it is also possible to form a wet sheet on a substrate by extruding the mixture (wet powder) from a die (preferably T die) provided with a predetermined gap. A common material, such as a glass sheet, a metal sheet, or a plastic sheet, may be used as the substrate. A common extruder can be used for extrusion.

(3) Step 3

[0040] In this step, the wet sheet is dried. For example, this step can be performed for a laminate through the following procedure. 1) Either substrate film is released. 2) The resulting laminate is dried using a circulation dryer. The drying temperature may be room temperature but is preferably 50°C to 100°C, and the drying time may be set to 1 to 2 minutes. 3) Subsequently, a smoking composition sheet is obtained by releasing the other substrate film and further drying under the above-mentioned conditions. By performing drying like this, it is possible to avoid attachment of the smoking composition sheet to other substrates. A smoking composition sheet thus obtained is also referred to as " laminate sheet." Such a laminate sheet is preferable since the sheet exhibits surface smoothness and can suppress generation of detached shreds when comes into contact with other members. Further, this method is suitable for the production of a sheet of 300 µm or less.

[0041] In the case of extrusion, the wet sheet on a substrate is dried with air or heating. The drying conditions are as mentioned above. A smoking composition sheet thus obtained is also referred to as "extruded sheet." Such an extruded sheet is preferable since the sheet exhibits surface smoothness and can suppress generation of detached shreds when comes into contact with other members. This method is suitable for the production of a sheet of 200 µm or more.

[0042] Alternatively, a smoking composition sheet can also be produced by a papermaking process, a casting process, or a nonwoven fabric coating process, for example. A papermaking process is a process of producing a sheet by forming a mixture containing a humectant, a binder, either or both of a flavoring agent and a forming aid, and water into a sheet, followed by drying. Here, since the mixture needs to contain a fibrous substance, a tobacco raw material as a flavoring agent is a defibrated tobacco raw material, or the mixture contains pulp as a forming aid. A water extract obtained before defibration of a tobacco raw material may be concentrated later and applied back to the formed sheet. A sheet produced by this method is referred to as a sheet formed by a papermaking process.

[0043] A casting process is a process of producing a sheet by casting, on a substrate, a mixture containing a humectant, a binder, and either or both of a flavoring agent and a forming aid, followed by drying. The mixture preferably contains a pulverized tobacco raw material as a flavoring agent and may contain, as necessary, a forming aid and a medium, such as water. A sheet produced by this method is referred to as a cast sheet.

[0044] A nonwoven fabric coating process is a process of producing a sheet by applying, to a nonwoven fabric, a mixture containing a humectant, a binder, and either or both of a flavoring agent and a forming aid. A sheet produced by this method is referred to as a nonwoven fabric sheet.

3. Smoking Articles

[0045] Exemplary smoking articles include flavor inhaler articles, in which a user tastes a flavor through inhalation, and smokeless tobacco (smokeless smoking articles), in which a user places the product directly in the nasal or oral cavity to taste a flavor. Flavor inhaler articles are broadly divided into non-combustion smoking articles and combustion-type smoking articles represented by conventional cigarettes. A smoking composition sheet of the present invention is suitable for flavor inhaler articles.

[0046] Exemplary combustion-type flavor inhaler articles include cigarettes, pipes, kiseru or Japanese smoking pipes, cigars, and cigarillos.

[0047] A heat-not-burn flavor inhaler article may be heated by a heating device separate from the article or may be heated by a heating device integrated with the article. In the former flavor inhaler article (separate-type), a heat-not-burn flavor inhaler article and a heating device are also collectively referred to as "heat-not-burn smoking system." Hereinafter, an exemplary heat-not-burn smoking system will be described with reference to Figs. 2 and 3.

[0048] Fig. 2 is a schematic cross-sectional view of an exemplary heat-not-burn smoking system and illustrates the state before inserting a heater 12 into a smoking segment 20A of a heat-not-burn flavor inhaler article 20. During use, the heater 12 is inserted into the smoking segment 20A. Fig. 3 is a cross-sectional view of a heat-not-burn flavor inhaler article 20.

[0049] As illustrated in Fig. 2, the heat-not-burn smoking system includes a heat-not-burn flavor inhaler article 20 and a heating device 10 for heating the smoking segment 20A from the inside. However, the heat-not-burn smoking system is not limited to the structure in Fig. 2.

[0050] The heating device 10 illustrated in Fig. 2 includes a body 11 and a heater 12. Although not illustrated, the body 11 may include a battery unit and a control unit. The heater 12 may be an electric resistance heater and is inserted into the smoking segment 20A to heat the smoking segment 20A.

[0051] A smoking composition sheet of the present invention is highly effective when the smoking segment 20A is heated from the inside as illustrated in Fig. 2. Since the smoking composition sheet comes into direct contact with a heater in such a heating mode, it is possible to attain an excellent profile due to the further enhanced release efficiency of a humectant from the sheet. However, the embodiment of the heat-not-burn flavor inhaler article 20 is not limited to this. In another embodiment, the smoking segment 20A is heated from the outside.

[0052] The heating temperature by the heating device 10 is not particularly limited but is preferably 400°C or lower, more preferably 50°C to 400°C, and further preferably 150°C to 350°C. Herein, the heating temperature means the temperature of the heater 12 in the heating device 10.

[0053] As illustrated in Fig. 3, the heat-not-burn flavor inhaler article 20 (hereinafter, simply referred to as "flavor inhaler article 20") has a cylindrical shape. The flavor inhaler article 20 has a circumferential length of preferably 16 mm to 27 mm, more preferably 20 mm to 26 mm, and further preferably 21 mm to 25 mm. The entire length (length in the horizontal direction) of the flavor inhaler article 20 is not particularly limited but is preferably 40 mm to 90 mm, more preferably 50 mm to 75 mm, and further preferably 50 mm to 60 mm.

[0054] The flavor inhaler article 20 comprises a smoking segment 20A, a filter section 20C that forms a mouthpiece, and a connection section 20B that connects the smoking segment 20A and the filter section 20C.

[0055] The smoking segment 20A is cylindrical. The entire length (length in the axial direction) is, for example, preferably 5 to 100 mm, more preferably 10 to 50 mm, and further preferably 10 to 25 mm. The cross-sectional shape of the smoking segment 20A is not particularly limited but may be circular, elliptic, or polygonal, for example.

[0056] The smoking segment 20A includes a smoking composition sheet or a material derived therefrom 21 and a wrapper 22 wrapped therearound. The wrapper 22 may be a smoking composition sheet 1 of the present invention.

[0057] The filter section 20C is cylindrical. The filter section 20C includes a rod-shaped first segment 25 filled with cellulose acetate fibers and a rod-shaped second segment 26 similarly filled with cellulose acetate fibers. The first segment 25 is positioned on the side of the smoking segment 20A. The first segment 25 may have a hollow portion. The second segment 26 is positioned on the mouth side. The second segment 26 is solid. The first segment 25 comprises a first filling layer (cellulose acetate fibers) 25a and an inner plug wrapper 25b wrapped around the first filling layer 25a. The second segment 26 comprises a second filling layer (cellulose acetate fibers) 26a and an inner plug wrapper 26b wrapped around the second filling layer 26a. The first segment 25 and the second segment 26 are joined by an outer plug wrapper 27. The outer plug wrapper 27 is bonded to the first segment 25 and the second segment 26 using a vinyl acetate emulsion adhesive, for example.

[0058] The length of the filter section 20C may be set to 10 to 30 mm, for example, the length of the connection section 20B to 10 to 30 mm, for example, the length of the first segment 25 to 5 to 15 mm, for example, and the length of the second segment 26 to 5 to 15 mm, for example. The lengths of these individual segments are examples and may be changed appropriately depending on production feasibility, required quality, the length of the smoking segment 20A, and so forth.

[0059] For example, the first segment 25 (center hole segment) comprises a first filling layer 25a having one or more hollow portions and an inner plug wrapper 25b that covers the first filling layer 25a. The first segment 25 acts to enhance the strength of the second segment 26. The first filling layer 25a of the first segment 25 is, for example, cellulose acetate fibers packed at high density. The cellulose acetate fibers are, for example, added with 6 to 20 mass%, based on the mass of cellulose acetate, of a plasticizer including triacetin and hardened. The hollow portion of the first segment 25 has an inner diameter of ⌀1.0 to ⌀5.0 mm, for example.

[0060] The first filling layer 25a of the first segment 25 may be formed, for example, at a relatively high filling density of fibers or at a filling density of fibers comparable to the second filling layer 26a of the second segment 26 described hereinafter. Consequently, air and an aerosol flow only through the hollow portion and hardly flow within the first filling layer 25a during inhalation. For example, when it is desirable to suppress reduction in aerosol components through filtration in the second segment 26, it is also possible to shorten the second segment 26 and extend the first segment 25 by the corresponding length.

[0061] Replacing the shortened second segment 26 by the first segment 25 is effective for increasing the amount of aerosol components to be delivered. Since the first filling layer 25a of the first segment 25 is a fiber filling layer, the touch from the outside during use does not cause any discomfort to a user.

[0062] The second segment 26 comprises a second filling layer 26a and an inner plug wrapper 26b that covers the second filling layer 26a. The second segment 26 (filter segment) is filled with cellulose acetate fibers at common density and thus exhibits typical filtration performance of aerosol components.

[0063] The first segment 25 and the second segment 26 may be different in filtration performance of an aerosol (mainstream smoke) released from the smoking segment 20A. Further, at least either of the first segment 25 and the second segment 26 may contain a flavor. The structure of the filter section 20C is optional and may be a structure having a plurality of segments as mentioned above or a structure of a single segment. In the case in which the filter section 20C is formed from one segment, the filter section 20C may comprise either the first segment or the second segment.

[0064] The connection section 20B is cylindrical. The connection section 20B includes a cylindrically formed paper tube 23 of cardboard, for example. The connection section 20B may be filled with a cooling member for cooling an aerosol. Exemplary cooling members include a polymer sheet of polylactic acid, for example, and such a sheet may be folded and packed therein. Further, a support may be provided between the smoking segment 20A and the connection section 20B for suppressing the displacement of the smoking segment 20A. Such a support may be formed of a common material, such as a center hole filter like the first segment 25.

[0065] A wrapper 28 is cylindrically wrapped around the smoking segment 20A, the connection section 20B, and the filter section 20C to join these components integrally. On either side (inner side) of the wrapper 28, almost the whole surface or the whole surface excluding near a ventilation hole portion 24 is coated with a vinyl acetate emulsion adhesive. A plurality of ventilation hole portions 24 are formed by laser processing from the outside after the smoking segment 20A, the connection section 20B, and the filter section 20C are integrated by the wrapper 28.

[0066] The ventilation hole portion 24 includes two or more penetrating holes in the thickness direction of the connection section 20B. Two or more penetrating holes are formed in radial arrangement when viewed from the extension of the central axis of the flavor inhaler article 20. The ventilation hole portion 24 is provided on the connection section 20B in this embodiment but may be provided on the filter section 20C. Moreover, two or more penetrating holes of the ventilation hole portion 24 are provided aligning in one row or on one ring at certain intervals in this embodiment but may be provided aligning in two rows or on two rings at certain intervals. Further, the ventilation hole portion 24 in one or two rows may be provided aligning discontinuously or irregularly. When a user inhales with the mouthpiece in the mouth, external air is taken into mainstream smoke through the ventilation hole portion 24. Nevertheless, the ventilation hole portion 24 need not necessarily be provided.

EXAMPLES

[Example 1]

[0067] Tobacco leaves were pulverized to attain D90 of 70 µm using a grinding mill (ACM-5 from Hosokawa Micron Corporation), thereby yielding leaf tobacco particles. The D90 was measured using Mastersizer (from Malvern Panalytical Ltd.). The leaf tobacco particles and carboxymethyl cellulose (Sunrose F30MC from Nippon Paper Industries Co., Ltd.) as a binder were dry-blended using a mixer. Subsequently, the resulting dry blend was added with glycerol as a humectant and water as a medium and mixed using a mixer to prepare a wet powder. The composition of the respective components is as shown in Table 1.

[0068] The wet powder was kneaded six times at room temperature using a kneader (DG-1 from Dalton Corporation) to yield a mixture. A T die was used as a die, and the screw rotation speed was set to 38.5 rpm.

[0069] The wet powder was sandwiched between two Teflon^™ films (Nitoflon^® No. 900UL from Nitto Denko Corporation) and rolled at four stages using a calendaring machine (from Yuri Roll Machine Co., Ltd.) to attain a predetermined thickness (over 100 µm), thereby preparing a 105 µm-thick laminate having a layered structure of film/wet sheet/film. The roll gaps for the first to the fourth stages were respectively set to 650 µm, 330 µm, 180 µm, and 5 µm. The roll gap for the fourth stage is smaller than the thickness of the finally obtained sheet. This is because the sheet released from the pressure between the rollers expanded near the final thickness.

[0070] The laminate, after releasing one Teflon^™ film therefrom, was dried at 80°C for 1 to 2 minutes using a circulation dryer. Subsequently, a wet sheet after releasing the other film was dried under the same conditions to produce a smoking composition sheet of the present invention.

[0071] The smoking composition sheet thus obtained was left under conditions of room temperature at 22°C and 60% relative humidity for 48 hours. Subsequently, a plurality of holes of 0.2 mm × 0.2 mm in size were formed on the sheet using a laser machine (from Trotec Laser GmbH). The holes were equally spaced at an interval of 0.4 mm. The detailed conditions are shown in Table 2. For the processed smoking composition sheet thus obtained, an air permeability and a release profile were evaluated by the methods described hereinafter. The results are shown in Table 2 and Fig. 4. The vertical axis in Fig. 4 represents the amount of nicotine standardized by the amount of nicotine per flavor inhaler article. In other words, x/y values are plotted on the vertical axis where x (g) is the amount of nicotine detected per puff and y (g) is the amount of nicotine per article (the amount of nicotine for 1 to 14 puffs in total).

< Air Permeability >

[0072] The perforated sheet was left under conditions of room temperature at 22°C and 60% relative humidity for 48 hours. Subsequently, the sheet was cut into the size of 40 mm × 240 mm, and the air permeability was measured using a permeability unit (PPM 1000M from Cerulean) under measuring conditions of 1 kPa pressure difference and a circular measuring head of 2 cm². The measurement environment was set to room temperature at 22°C and 60% relative humidity. The air permeability was calculated as a flow rate of air (cm³) per 1 cm² for 1 minute at a pressure difference of 1 kPa.

< Component Release Profile >

[0073] 

1) The perforated sheet was left under conditions of room temperature at 22°C and 60% relative humidity for 48 hours.

2) The thickness and the basis weight were measured to calculate a sheet density.

3) The sheet was cut into the size of 55 mm × 0.8 mm.

4) A cigarette tube of ⌀7.1 was filled with the cut sheet at a predetermined volumetric filling rate and cut into the 12 mm length.

5) The 12 mm-long smoking segment (tobacco segment), a filter, and a paper tube were joined to produce a roll for a smoking test (flavor inhaler article).

6) An internal-heating non-combustion smoking system illustrated in Fig. 2 was prepared. Subsequently, a Cambridge filter was connected to the mouth end. A sheet produced in each example was cut into shreds. The shreds were packed within a wrapper 22 of 12 mm in length and 7 mm in diameter at 70 volume% to prepare a smoking segment 20A. The system was subjected to a smoking test using a smoking machine. Specifically, a sample was subjected to automatic smoking by an automatic smoking machine (R-26 from Borgwaldt KC Inc.) under the conditions of puff volume of 27.5 mL/s, puff duration of 2 s/puff, puff frequency of 2 puffs/min, and 14 puffs. The resulting particulate matter in tobacco smoke per puff was collected by a Cambridge filter (CM-133 from Borgwaldt KC Inc.). The Cambridge filter after the smoking test was shaken in 10 mL of methanol (GR-grade, from Wako Pure Chemical Industries, Ltd.) to obtain an analysis sample. From the analysis sample, 1 µL was collected by a microsyringe and analyzed by GC-MS (GC-MSD, GC: 7890A, MS: 5975C from Agilent Technologies, Inc.).

[Table 1]

[0074] 

Table 1 Composition in Examples and Comparative Example

	DB weight%	WB weight%
Pulverized tobacco leaves	85	60
Binder	3	2
Glycerol	12	8
Other additives	0	0
Water	-	30

DB: dry-based WB: wet-based

[Examples 2 to 4 and Comparative Example 1]

[0075] Each sheet having the air permeability shown in Table 2 was prepared by changing laser processing conditions. A roll for a smoking test was prepared and evaluated in the same manner as Example 1 except for using each sheet and changing the filling rate. The results are shown in Fig. 4.

[Table 2]

	Air permeability (CU)	Hole interval (mm)	Hole size (mm × mm)	Perforation speed setting	Laser output	Volumetric filling rate
Comp. Ex. 1	0	0.4	0.2 × 0.2	10	15	65%
Ex. 1	601	0.4	0.2 × 0.2	10	16.25	70%
Ex. 2	4695	0.4	0.2 × 0.2	10	17.5	73%
Ex. 3	12199	0.4	0.2 × 0.2	10	20	70%

As shown in the figure, the smoking articles using a smoking composition sheet of the present invention attain an excellent profile that exhibits high delivery at initial puffs and ensures delivery comparable to a conventional sheet at later puffs.

REFERENCE SIGNS LIST

[0076] 

1

Smoking composition sheet

1c

Cut piece of smoking composition sheet

10

Heating device

11

Body

12

Heater

20

Heat-not-burn flavor inhaler article

20A

Smoking segment

20B

Connection section

20C

Filter section

21

Smoking composition sheet or material derived therefrom

22

Wrapper

23

Paper tube

24

Ventilation hole portion

25

First segment

25a

First filling layer

25b

Inner plug wrapper

26

Second segment

26a

Second filling layer

26b

Inner plug wrapper

27

Outer plug wrapper

28

Wrapper

Claims

1. A smoking composition sheet having an air permeability of more than 0 CORESTA Unit (CU) and comprising:

a humectant;

a binder; and

either or both of a flavoring agent and a forming aid.

2. The sheet according to Claim 1, having the air permeability of 500 CU or more.

3. The sheet according to Claim 1 or 2, wherein the flavoring agent is selected from the group consisting of tobacco, flavors, and combinations thereof.

4. The sheet according to any of Claims 1 to 3, wherein the humectant is a polyhydric alcohol.

5. The sheet according to any of Claims 1 to 4, wherein the binder is selected from the group consisting of polysaccharides, proteins, synthetic polymers, and combinations thereof.

6. The sheet according to any of Claims 1 to 5, wherein the forming aid is pulp or a nonwoven fabric of plant fibers or synthetic fibers.

7. The sheet according to any of Claims 1 to 6, being a pressure-formed sheet..

8. The sheet according to any of Claims 1 to 6, having a plurality of holes formed through physical processing.

9. The sheet according to any of Claims 1 to 7, having a plurality of holes formed through chemical processing.

Drawing