EP4256982A1

EP4256982A1 - Filter segment and tobacco product

Info

Publication number: EP4256982A1
Application number: EP20964271.9A
Authority: EP
Inventors: Tetsuya Motodamari; Shintaro Hashimoto; Shingo Miyamoto
Original assignee: Japan Tobacco Inc
Current assignee: Japan Tobacco Inc
Priority date: 2020-12-03
Filing date: 2020-12-03
Publication date: 2023-10-11
Also published as: WO2022118418A1; JPWO2022118418A1; JP7503653B2

Abstract

Provided is a filter segment that suppresses the displacement of a breakable capsule even when an external force is applied thereto. A filter segment according to the present invention is a filter segment for a tobacco product, including: a filter containing fibers; and a breakable capsule embedded in the filter to be located on the central axis of the filter segment, where the filter segment has a first hardened structure that is formed of the fibers located near the breakable capsule and fused together by a plasticizer to cover the breakable capsule or a second hardened structure that is formed of the fibers located near the central axis of the filter segment and fused together by the plasticizer.

Description

TECHNICAL FIELD

The present invention relates to a filter segment and a tobacco product.

BACKGROUND ART

A tobacco product, for example, a common cigarette includes a tobacco-containing segment, which has been formed into a rod shape by wrapping a cigarette paper around dried tobacco leaves, and a filter segment, which has been formed into a rod shape by wrapping a filter wrapper around a filter that contains one or more cellulose acetate fiber bundles or around a filter prepared by bundling or folding one or more pulp-containing nonwoven fabrics. Such a cigarette is obtained through integration of the tobacco-containing segment and the filter segment connected to each other at the ends by wrapping a tipping paper around the whole circumference for bonding.
Such a cigarette is a combustible tobacco product that generates smoke by burning the tip of the tobacco-containing segment. Exemplary combustible tobacco products other than such cigarettes include cigars and cigarillos. Moreover, in addition to combustible tobacco products, exemplary tobacco products include non-combustion-heating tobacco products that generate a flavor component through heating without burning of the tobacco-containing segment, which contains tobacco, a flavor component, and an aerosol former, such as glycerol (Patent Literature (PTL) 1 and 2, for example). Exemplary methods of heating without burning include heating methods by electrical resistance, IH, chemical changes, or phase transition.
Concerning filter segments, incorporating a flavor-containing breakable capsule into a filter has been practiced conventionally to enjoy the aroma of liquid contents during inhalation or to mask the smell of an extinguished cigarette butt by rupturing the breakable capsule with fingers during use (PTL 3 to 6, for example).

CITATION LIST

PATENT LITERATURE

PTL 1: Japanese Patent No. 5990500
PTL 2: Japanese Patent No. 5292410
PTL 3: Japanese Patent No. 6078657
PTL 4: Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2007-520204
PTL 5: Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2016-533764
PTL 6: Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2016-524924

SUMMARY OF INVENTION

TECHNICAL PROBLEM

For the filter segment of a cigarette or a cigarillo, many functions are required, such as filtering smoke, diluting smoke, imparting a flavor to smoke, holding a second filter (activated carbon or the like) or members excluding filters, and adjusting the pressure drop. Meanwhile, for the filter segment of a non-combustion-heating tobacco product, more functions are required, such as filtering an aerosol, diluting an aerosol, imparting a flavor to an aerosol, cooling an aerosol, holding a second filter (activated carbon or the like) or members excluding filters, and adjusting the pressure drop. For these reasons, the filter segment of a cigarette or a non-combustion-heating tobacco product has recently been required to include a plurality of filter segments that bear the respective functions as well as to shorten the length in the axial direction of each filter segment to about 5 to 15 mm.
Filter segments are typically manufactured by cutting, on a plane perpendicular to the longitudinal direction, a continuous bar which has been prepared by bundling many long fibers, such as cellulose acetate fibers, followed by continuous winding. Since the fibers that constitute a filter segment extend almost parallel to the axial direction of the filter segment, the filter segment containing a breakable capsule sometimes undergoes the displacement of the breakable capsule when an external force is applied thereto. When the displacement of a breakable capsule occurs, it is impossible in some cases to rupture the breakable capsule easily. A filter segment, particularly when the length in the axial direction is short, exhibits low holding ability of a breakable capsule due to a fewer portions of fibers tangled together and thus readily undergoes the displacement of the breakable capsule when an external force is applied thereto. Further, noticeable displacement could possibly force the breakable capsule outside the filter segment.
The object of the present invention is to provide a filter segment that suppresses the displacement of a breakable capsule even when an external force is applied thereto and a tobacco product including the filter segment.

SOLUTION TO PROBLEM

A filter segment according to the present invention is a filter segment for a tobacco product, including

a filter containing fibers and
a breakable capsule embedded in the filter to be located on the central axis of the filter segment, where the filter segment has
a first hardened structure that is formed of the fibers located near the breakable capsule and fused together by a plasticizer to cover the breakable capsule or
a second hardened structure that is formed of the fibers located near the central axis of the filter segment and fused together by the plasticizer.

A tobacco product according to the present invention, includes

a tobacco-containing segment and
the filter segment according to the present invention.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a filter segment that suppresses the displacement of a breakable capsule even when an external force is applied thereto and a tobacco product including the filter segment.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a cross-sectional view of an exemplary filter segment according to the present invention.
Fig. 2 is a cross-sectional view of an exemplary filter segment according to the present invention, having a first hardened structure and a second hardened structure.
Fig. 3 is a cross-sectional view of a cylindrical region and a fan-shaped columnar region of an exemplary filter segment according to the present invention.
Fig. 4 is a schematic view of an exemplary manufacturing apparatus for a filter segment used for manufacturing a filter segment according to the present invention.
Fig. 5 is an enlarged schematic view of a portion around a breakable capsule feeder of an exemplary manufacturing apparatus for a filter segment.
Fig. 6 is a cross-sectional view illustrating an exemplary state when a breakable capsule is embedded in fibers by a breakable capsule feeder.
Fig. 7 is a schematic horizontal cross-sectional view of an exemplary continuous fiber bundle before cutting.
Fig. 8 is a cross-sectional view of an exemplary tobacco product (cigarette) according to the present invention.
Fig. 9 is a cross-sectional view of another exemplary tobacco product (cigarette) according to the present invention.
Fig. 10 is a schematic view of exemplary heating device and tobacco product (non-combustion-heating tobacco product) according to the present invention.
Fig. 11 is a magnified image showing the fused state between a breakable capsule and cellulose acetate fibers present around the breakable capsule in the filter segment of Example 1.
Fig. 12 is a magnified image showing a cocoon-like first hardened structure of cellulose acetate fibers fused together by triacetin, which was formed around the breakable capsule in the filter segment of Example 1.
Fig. 13 is a magnified image showing an exemplary second hardened structure of a filter segment according to the present invention.
Fig. 14 is a schematic view of a pinch tester used for evaluating the displacement of a breakable capsule in the Examples and Comparative Examples.

DESCRIPTION OF EMBODIMENTS

[Filter Segment]

A filter segment according to the present invention is a filter segment for a tobacco product, including: a filter containing fibers; and a breakable capsule embedded in the filter to be located on the central axis of the filter segment. Such a filter segment may be disposed downstream of a tobacco-containing segment in a tobacco product and may be disposed at the mouth end of the tobacco product. Here, the filter segment has a first hardened structure that is formed of the fibers located near the breakable capsule and fused together by a plasticizer (hereinafter, referred to as first plasticizer) to cover the breakable capsule or a second hardened structure that is formed of the fibers located near the central axis (hereinafter, also referred to as axis A) of the filter segment and fused together by the plasticizer.
In a filter segment having the first hardened structure, a breakable capsule is covered, like a cocoon, by the first hardened structure. Consequently, it is possible to restrict the movement of the breakable capsule even when a force is applied from the outside of the filter and thus to suppress the displacement of the breakable capsule. Further, in a filter segment having the second hardened structure, the movement of a breakable capsule is restricted by the presence of the second hardened structure that is formed near axis A to extend in the axial direction of the filter segment from the breakable capsule. Consequently, it is possible to suppress the displacement of the breakable capsule.
In particular, even when the length in the axial direction of a filter segment is short as 5 to 15 mm, for example, and hence the fibers that constitute the filter segment exhibit low holding ability of a breakable capsule, it is possible according to the present invention to satisfactorily suppress the displacement of the breakable capsule. Moreover, a plasticizer the same as those commonly added in advance uniformly to fibers that constitute a filter for the purpose of adjusting the hardness of the filter, such as triacetin (hereinafter, also referred to as second plasticizer), may be used as the first plasticizer. For this reason, it is not needed to separately use, for fusing, a common adhesive, which is not usually added to a filter. Consequently, it is possible to suppress the displacement of a breakable capsule without altering the physical properties of a filter as well as to reduce the manufacturing costs. Here, the second plasticizer, which is added in advance uniformly to fibers before embedding a breakable capsule, does not contribute to local fusion of fibers. In other words, a conventional filter segment has neither the first hardened structure nor the second hardened structure according to the present invention. A filter segment according to the present invention preferably has both the first hardened structure and the second hardened structure since the displacement of a breakable capsule can be suppressed further.
Moreover, in a preferable embodiment of a filter segment according to the present invention, a breakable capsule and fibers that constitute a filter are fused by the first plasticizer. In this embodiment, it is possible by such fusion to further suppress the displacement of the breakable capsule even when a force is applied from the outside of the filter. Here, the above-mentioned second plasticizer, which has been added in advance uniformly to fibers before embedding a breakable capsule and thus has solidified at the time of embedding the breakable capsule, does not contribute to the fusion between the breakable capsule and fibers that constitute a filter. In other words, a breakable capsule and fibers that constitute a filter are not fused by a plasticizer in a conventional filter segment. Hereinafter, the details of the present invention will be described.
Fig. 1 illustrates an exemplary filter segment according to the present invention. A filter segment 10 illustrated in Fig. 1 is cylindrical and includes a filter 11, a breakable capsule 12, and a filter wrapper 13. The filter 11 is formed from fibers, such as cellulose acetate fibers. The fibers extend almost parallel to the axial direction (horizontal direction in Fig. 1) of the filter segment 10. The breakable capsule 12 is embedded in the filter 11 and thus present within the fibers. Moreover, the breakable capsule 12 is located on axis A, which is the central axis of the filter segment 10. The filter segment 10 has a first hardened structure 14, which is formed of fibers located near the breakable capsule 12 and fused together by a first plasticizer to cover the breakable capsule 12, and a second hardened structure 15, which is formed of fibers located near axis A and fused together by the first plasticizer. In the filter segment 10, the first hardened structure 14 and the second hardened structure 15 are joined, and the second hardened structure 15 is formed to extend along axis A from the first hardened structure 14. Although not illustrated in Fig. 1, the surface of the breakable capsule 12 and fibers of the filter 11 located near the breakable capsule 12 are fused by the first plasticizer. The filter wrapper 13, such as paper, is wrapped around the filter 11 that contains the breakable capsule 12. However, the filter wrapper 13 need not necessarily be wrapped around the filter 11. Here, when the end faces of the filter segment 10 are not perfect circular, the above-mentioned axis A is represented as a line segment connecting the center of gravity on either end face to the center of gravity on the other end face of the filter segment 10 through the breakable capsule 12.

(Filter)

A filter contains fibers. Such fibers may extend almost parallel to the axial direction (central axis) of the filter segment. Herein, the expression of extending "almost parallel" to the axial direction of the filter segment indicates that fibers extend in a direction within the ±10° range of the axial direction of the filter segment. Examples of such fibers include cellulose acetate fibers and polypropylene fibers, and cellulose acetate fibers are preferable. An acetate tow as a bundle of cellulose acetate fibers may have, for example, filament denier: 1.9 to 12.0 (g/9000 m), total denier: 10,000 to 44,000 (g/9000 m), the number of fibers: 830 to 23,500, pressure drop: 100 to 800 (mmH₂O/120 mm), and tow mass: 0.300 to 1.100 (g/filament).

(Breakable Capsules)

In the present invention, a "breakable capsule" indicates a capsule that can be ruptured by applying an external force. Such a breakable capsule may include a shell and liquid contents including a flavor and so forth retained inside the shell. Exemplary materials for the shell include edible materials, such as starch, dextrin, polysaccharides, agar, gellan gum, gelatin, natural gelling agents, glycerol, sorbitol, and calcium chloride. These materials may be used alone or in combination of two or more. In other words, the surface of a breakable capsule may be formed from at least one compound selected from the group consisting of starch, dextrin, polysaccharides, agar, gellan gum, gelatin, natural gelling agents, glycerol, sorbitol, and calcium chloride. These materials largely have high hydrophilicity and thus can exhibit excellent affinity for a compatible mixture of an amphiphilic first plasticizer and a fiber material and hence excellent fusing properties. The shell may further contain a flavor. Moreover, a breakable capsule is preferably colored such that a user can easily recognize the position of the breakable capsule when rupturing the breakable capsule. In this view, the shell preferably contains a colorant, such as Blue No. 1.
Any flavor used for tobacco products, such as menthol and plant essential oils, may be used as a flavor of the liquid contents. Concrete examples include menthol, leaf tobacco extracts, natural plant flavors (cinnamon, sage, herb, chamomile, kudzu vine, hydrangea tea, clove, lavender, cardamom, nutmeg, bergamot, geranium, honey essence, rose oil, lemon, orange, Chinese cinnamon, caraway, jasmine, ginger, coriander, vanilla extract, spearmint, peppermint, cassia, coffee, celery, cascarilla, sandalwood, cocoa, ylang-ylang, fennel, anise, licorice, St. John's bread, plum extract, peach extract, for example), sugars (glucose, fructose, high-fructose corn syrup, caramel, for example), cocoa (powder, extract, and so forth), esters (isoamyl acetate, linalyl acetate, isoamyl propionate, linalyl butyrate, for example), ketones (menthone, ionones, damascenones, ethyl maltol, for example), alcohols (geraniol, linalool, anethole, eugenol, for example), aldehydes (vanillin, benzaldehyde, anisaldehyde, for example), lactones (γ-undecalactone, γ-nonalactone, for example), animal perfume (musk, ambergris, civet, castoreum, for example), and hydrocarbons (limonene, pinene, for example). These flavors may be used alone or as mixtures of two or more.
The liquid contents may include a solvent. Any solvent suitable for a flavor may be used as the solvent, and examples include medium-chain triglycerides (MCTs) (specifically, glyceryl tricaprylate/caprate), propylene glycol, water, and ethanol. The liquid contents may further include other solvents or other additives, such as a dye, an emulsifier, and a thickener.
A manufacturing method for breakable capsules is not particularly limited but may adopt a dropping process, for example. In a dropping process, it is possible, by using a double nozzle and simultaneously discharging liquid contents from the inner nozzle and a liquid shell substance from the outer nozzle, to enclose the liquid contents seamlessly with the shell liquid. According to the process, it is thus possible to manufacture breakable capsules each having a seamless shell.
The shape of a breakable capsule is not particularly limited and may be spherical or cylindrical, for example. Such a spherical shape encompasses both an almost spherical shape having an almost circular cross-section and an oval shape having an elliptic cross-section. A breakable capsule is preferably almost spherical in shape. Herein, "almost spherical" indicates sphericity of 95% or more. The sphericity is calculated by feeding 100 g of breakable capsules to CAMSIZER P4 (trade name, from Retsch Technology GmbH) analyzer, analyzing the major and minor axes from an image of each capsule taken by a CCD camera equipped with the analyzer, and calculating using the new particle shape descriptor function of the analyzer.
When a breakable capsule is almost spherical in shape, the diameter of the breakable capsule (the maximum cross-sectional length of the breakable capsule) is preferably 1.0 to 3.5 mm, more preferably 1.5 to 3.5 mm, and further preferably 2.0 to 3.5 mm. When the diameter of a breakable capsule is 1.0 mm or more, it is possible to load a sufficient amount of liquid contents including a flavor within the shell of the breakable capsule and hence to provide full satisfaction to a user. Moreover, a user can easily recognize the position of the breakable capsule when rupturing the breakable capsule. Meanwhile, when the diameter of a breakable capsule is 3.5 mm or less, it is possible to reduce the ratio of the cross-sectional area of the breakable capsule to the cross-sectional area of a filter segment and hence to suppress the increase in pressure drop of the filter segment due to the presence of the breakable capsule. Consequently, the ease in inhalation by a user improves. Further, a breakable capsule may have tiny protrusions present on the surface. The presence of the protrusions, which act as the points of fusion with fibers, makes it possible to further satisfactorily fuse the breakable capsule and fibers by a first plasticizer.
A breakable capsule is embedded in a filter and thus present within fibers that constitute the filter. One or two or more (two to ten, for example) breakable capsules may be embedded in the filter of one filter segment. Such a breakable capsule is disposed at a position that overlaps axis A, which is the central axis of a filter segment, and the center of the breakable capsule is preferably located on axis A. Further, when the position of the mouth side end is set to 0% and the position of the opposite side end to 100% in the axial direction of a filter, the center of a breakable capsule is located preferably in a zone of 16.7% to 83.3% and more preferably in a zone of 30.0% to 53.3%. When the center of a breakable capsule is located in a zone of 16.7% or more, it is possible to further prevent the breakable capsule from being forced outside the filter segment due to noticeable displacement. Meanwhile, when a breakable capsule is present in a zone of 83.3% or less, a user can easily rupture the breakable capsule not only with fingers but also by chewing during use. Moreover, since a flavor source is close to the mouth end, a user can taste a further intense flavor.
The outer shell ends of a breakable capsule may be located in a zone of 10.8 to 89.2% as the maximum zone, a zone of 12.0 to 88.0% as a smaller zone, a zone of 32.5% to 67.5% as a further smaller zone, or a zone of 36.0% to 64.0% as the smallest zone. Moreover, when the center of a breakable capsule is located in the center between the mouth end and the opposite end of a filter segment, the outer shell ends of the breakable capsule may be located in a zone of 32.5% to 67.5% as the maximum zone, a zone of 36.0% to 64.0% as a smaller zone, a zone of 44.2% to 55.8% as a further smaller zone, or a zone of 45.3% to 54.7% as the smallest zone.

(First Hardened Structure)

A first hardened structure according to the present invention is a hardened structure formed of fibers located near a breakable capsule and fused together by a first plasticizer and covers, like a cocoon, at least part of the breakable capsule. Consequently, it is possible to suppress the movement of the breakable capsule even when a force is applied from the outside of the filter. In the first hardened structure, fibers located near a breakable capsule may be fused together at least partially by the first plasticizer. For example, as in the magnified image of Fig. 12, the first hardened structure may include a non-fused portion and a portion of fibers fused together by the first plasticizer. Here, Fig. 12 is a magnified image taken after removing a breakable capsule for convenience. The thickness of the first hardened structure may be 0.1 to 1.0 mm, for example.
As described hereinafter, a first hardened structure can be formed, for example, by applying a first plasticizer in advance to the surface of each breakable capsule and embedding the breakable capsule in a filter by a member for inserting breakable capsules. In this case, the first plasticizer that has been applied to the surface of each breakable capsule diffuses to fibers located near the breakable capsule to fuse the fibers located near the breakable capsule together by the first plasticizer, thereby forming a cocoon-like first hardened structure that covers the perimeter of the breakable capsule.

(Second Hardened Structure)

A second hardened structure according to the present invention is a hardened structure formed of fibers located near axis A, which is the central axis of the filter segment, and fused together by a first plasticizer. In other words, the second hardened structure is formed continuously to extend along axis A from the breakable capsule. When a filter segment has such a second hardened structure, it is possible to suppress the displacement of a breakable capsule even when an external force is applied thereto. When a filter segment also has a first hardened structure, the second hardened structure is joined to the first hardened structure and is formed to extend along axis A from the first hardened structure. For example, as shown in Fig. 13, the first hardened structure that covers, like a cocoon, a breakable capsule is integrated with the second hardened structure that is formed to extend along axis A from the first hardened structure. Although a partially exposed breakable capsule is imaged for convenience in Fig. 13, the breakable capsule may be covered completely by the first hardened structure.
The second hardened structure may be, for example, cylindrical having axis A as its central axis. In this case, the diameter of such a cylinder may be smaller than the diameter of a breakable capsule, for example, may be 14.0 to 86.0% of the diameter of a breakable capsule, and may be 0.5 to 3.0 mm. In the second hardened structure, fibers located near axis A may be fused together by the first plasticizer at least partially. The second hardened structure may include a non-fused portion and a portion of fibers fused together by the first plasticizer.
The second hardened structure may also be formed in a portion extending from axis A to the periphery of the filter segment. In other words, the second hardened structure may be formed like a rib from fibers located near axis A and fused together by a first plasticizer as well as from fibers located in a portion extending from axis A to the periphery of the filter segment and fused together by the first plasticizer. For example, as illustrated in Fig. 2, a filter segment 20 may include a first hardened structure 22 that covers a breakable capsule 23 and a second hardened structure 24 that extends from axis A to the periphery of the filter segment 20. Both the first hardened structure 22 and the second hardened structure 24 are formed of fibers that constitute a filter 21 and are fused together by a first plasticizer. The first hardened structure 22 and the second hardened structure 24 may be thus joined and integrated.
As described hereinafter, a second hardened structure can be formed, for example, by applying a first plasticizer in advance to the surface of a member for inserting breakable capsules and by embedding each breakable capsule in a filter by the member. In this case, the first plasticizer that has been applied to the surface of the member for inserting breakable capsules diffuses to fibers that come into contact with the member when each breakable capsule is embedded in the filter by the member, in other words, fibers located near axis A as well as to fibers present in a region extending from axis A to the periphery of the filter segment to fuse the fibers together by the first plasticizer, thereby forming a second hardened structure. As described hereinafter, such a member is an insertion wheel, for example. When breakable capsules are continuously embedded at regular intervals in a long contiguous filter segment before cutting, a second hardened structure is continuously provided almost parallel to the axial direction of the filter segment. In other words, the second hardened structure is provided to extend linearly along the axial direction of the filter segment.

(Plasticizers)

A first plasticizer is not particularly limited provided that the plasticizer is an edible plasticizer commonly used for tobacco products, and examples include triethyl citrate, acetyl triethyl citrate, dibutyl phthalate, diallyl phthalate, diethyl phthalate, dimethyl phthalate, bis(2-methoxyethyl) phthalate, dibutyl tartrate, ethyl o-benzoylbenzoate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, N-ethyltoluenesulfonamide, triacetin, o-cresyl p-toluenesulfonate, triethyl phosphate, triphenyl phosphate, and tripropionin. These first plasticizers may be used alone or in combination of two or more. Among these plasticizers, triacetin is preferable as a first plasticizer.
As in the foregoing, a filter may contain, apart from a first plasticizer used for fusing, a second plasticizer that is commonly added in advance uniformly to fibers for the purpose of adjusting the hardness of a filter. Any plasticizer the same as the above-described first plasticizer used for fusing may be used as a second plasticizer. A first plasticizer and a second plasticizer may be the same or different. As in the foregoing, a second plasticizer contributes to neither the formation of the first or the second hardened structure nor the fusion between a breakable capsule and fibers.
In the present invention, the expression that "fibers are fused together by a first plasticizer" means that fibers may be fused together by a first plasticizer alone or fibers may be fused together by a compatible mixture of a first plasticizer and the fiber material. In other words, a portion of fibers fused together may just contain a first plasticizer. Moreover, in the present invention, the expression that "a breakable capsule and fibers are fused by a first plasticizer" means that: a breakable capsule and fibers may be fused by a first plasticizer alone; a breakable capsule and fibers may be fused by a compatible mixture of a first plasticizer and the fiber material; a breakable capsule and fibers may be fused by a compatible mixture of a first plasticizer and the shell material of the breakable capsule; or a breakable capsule and fibers may be fused by a compatible mixture of a first plasticizer, the shell material of the breakable capsule, and the fiber material. In other words, a fused portion between a breakable capsule and fibers may just contain a first plasticizer. Further, at least part of the surface of a breakable capsule and at least part of fibers located near the surface of the breakable capsule may be fused by a first plasticizer. The fusion between a breakable capsule and fibers by a first plasticizer can be judged from a magnified image near the surface of the breakable capsule and by identifying compounds contained in the fused portion. For example, on the magnified image of Fig. 11, it is confirmed that part of the breakable capsule surface and part of fibers are fused.
A as described hereinafter, a breakable capsule and fibers can be fused using a first plasticizer, for example, by applying the first plasticizer in advance to the surface of each breakable capsule and by embedding the breakable capsule in a filter using a member for inserting breakable capsules. In this case, the first plasticizer that has been applied to the surface of each breakable capsule is attached to fibers located near the breakable capsule to form, for example, a compatible mixture of the fiber material and the first plasticizer, thereby fusing the breakable capsule and fibers.

(Plasticizer Content)

The plasticizer content (the total of first plasticizer and second plasticizer) relative to the filter of the entire filter segment is preferably 5 to 15 mass%, preferably 7.8 to 13.3 mass%, more preferably 9.0 to 13.3 mass%, further preferably 10.3 to 13.3 mass%, and most preferably 12.1 to 13.3 mass%. When the content is 5 mass% or more, it is possible to satisfactorily form a first hardened structure and a second hardened structure as well as to adjust the hardness of the filter. Meanwhile, when the content is 15 mass% or less, it is possible to suppress deterioration in filter physical properties, such as pressure drop, due to a cavity formed within the filter and to reduce odor due to the plasticizer. The plasticizer content is quantified by gas chromatography.
The first plasticizer content relative to the filter of the entire filter segment is preferably 0.1 to 3 mass%, more preferably 0.2 to 2 mass%, and further preferably 0.3 to 1.5 mass%. The second plasticizer content relative to the filter of the entire filter segment is preferably 3 to 9 mass%, more preferably 4 to 8 mass%, and further preferably 5 to 7 mass%. When a first plasticizer and a second plasticizer are the same, the second plasticizer content can be calculated by measuring the second plasticizer content after applying the second plasticizer to fibers and before embedding, in a filter, one or more breakable capsules to which a first plasticizer has been attached. Moreover, the first plasticizer content can be calculated by subtracting the second plasticizer content from the total content of the first plasticizer and the second plasticizer.
When the diameter (the maximum cross-sectional length) of a breakable capsule is 5 mm or less (1.0 to 3.5 mm, for example), the plasticizer content (mass%, the total of first plasticizer and second plasticizer) in a zone near the breakable capsule, in other words, a zone of 5 mm width with the breakable capsule at the center (capsule neighboring zone) is, in the axial direction of the filter segment, preferably 1.05 times or more and more preferably 1.20 times or more of the plasticizer content (mass%, the total of first plasticizer and second plasticizer) in a zone adjacent to the neighboring zone, in other words, a zone excluding the neighboring zone (adjacent zone). When the plasticizer content in the capsule neighboring zone is 1.05 times or more of the plasticizer content in the adjacent zone, the plasticizer is high in concentration near the breakable capsule and thus contributes to the formation of a cocoon-like first hardened structure that covers the perimeter of the breakable capsule. Moreover, the breakable capsule and fibers are fused further firmly. Here, when a plurality of breakable capsules are contained in a filter segment, the above-mentioned conditions are preferably satisfied in every section containing a breakable capsule.
It is preferable that a filter segment is cylindrical and that the plasticizer content (mass%, the total of first plasticizer and second plasticizer) within a cylindrical region having axis A, which is the central axis of the filter segment, at the center and having a dimeter of 75% length (preferably 65% and more preferably 55%) of the diameter of the filter segment is higher than the plasticizer content (mass%, the total of first plasticizer and second plasticizer) in the filter segment outside the cylindrical region. When the plasticizer content within the cylindrical region is higher than the plasticizer content in the filter segment outside the cylindrical region, the plasticizer is high in concentration near a breakable capsule and thus contributes to the formation of a cocoon-like first hardened structure that covers the perimeter of the breakable capsule. Moreover, the breakable capsule and fibers are fused further firmly.
It is preferable that the plasticizer content within the cylindrical region is 5 to 20 mass% and the plasticizer content in the filter segment outside the cylindrical region is 3 to 8 mass%. It is more preferable that the plasticizer content within the cylindrical region is 6 to 18 mass% and the plasticizer content in the filter segment outside the cylindrical region is 4 to 7 mass%. It is further preferable that the plasticizer content within the cylindrical region is 6.7 to 16 mass% and the plasticizer content in the filter segment outside the cylindrical region is 5 to 6.4 mass%.
Furthermore, when a filter segment has the above-described second hardened structure of fibers located near axis A and fused together by a first plasticizer and of fibers located in a portion extending from axis A to the periphery of the filter segment and fused together by the first plasticizer, it is preferable that the filter segment is cylindrical and that the plasticizer content (mass%, the total of first plasticizer and second plasticizer) inside a cylindrical region having axis A at the center and having a diameter of 75% length (preferably 65% and more preferably 55%) of the diameter of the filter segment and inside a fan-shaped columnar region having a central angle of 30° to 90° and radially extending from axis A to the periphery of the filter segment is preferably higher than the plasticizer content (mass%, the total of first plasticizer and second plasticizer) in the filter segment outside the cylindrical region and the fan-shaped columnar region. Specifically, as illustrated in Fig. 3, the plasticizer content inside a cylindrical region 33 having axis A at the center and having a dimeter of 75% length of the diameter of a filter segment and inside a fan-shaped columnar region 34 having a central angle ø of 30° to 90° and radially extending from axis A to the periphery of the filter segment 30 is preferably higher than the plasticizer content in a region 31 outside the cylindrical region 33 and the fan-shaped columnar region 34. When the plasticizer content within the cylindrical region and the fan-shaped columnar region is higher than the plasticizer content in the filter segment outside the cylindrical region and the fan-shaped columnar region, the plasticizer contributes to the formation of a cocoon-like first hardened structure that covers the perimeter of the breakable capsule as well as to the formation of a second hardened structure that extend from axis A to the periphery of the filter segment. Moreover, the plasticizer is high in concentration near the breakable capsule, thereby fusing the breakable capsule and fibers further firmly.
It is preferable that the plasticizer content within the cylindrical region and the fan-shaped columnar region is 5 to 20 mass% and the plasticizer content in the filter segment outside the cylindrical region and the fan-shaped columnar region is 3 to 8 mass%. It is more preferable that the plasticizer content within the cylindrical region and the fan-shaped columnar region is 6 to 18 mass% and the plasticizer content in the filter segment outside the cylindrical region and the fan-shaped columnar region is 4 to 7 mass%. It is further preferable that the plasticizer content within the cylindrical region and the fan-shaped columnar region is 6.7 to 16 mass% and the plasticizer content in the filter segment outside the cylindrical region and the fan-shaped columnar region is 5 to 6.4 mass%.

(Dimensions and Physical Properties of Filter Segment)

From a viewpoint of further favorably attaining the effect of suppressing the displacement of a breakable capsule in the present invention, the length in the axial direction of a filter segment is preferably shorter and is, for example, preferably 5 to 15 mm, more preferably 7 to 15 mm, and further preferably 10 to 15 mm. The proportion (d/L) of the diameter (d) of a breakable capsule to the length (L) in the axial direction of a filter segment is preferably 0.1 to 0.5, more preferably 0.15 to 0.4, and further preferably 0.2 to 0.3. The perimeter length of a filter segment is not particularly limited but is preferably 16 to 25 mm and more preferably 20 to 24 mm.
The pressure drop of a filter segment is preferably 4 to 200 mmH₂O. The pressure drop of a filter segment is measured by a pressure drop meter (FQA, QTM, and so forth). When a filter segment is cylindrical, the circularity of the cross-section perpendicular to the axial direction of the filter segment is preferably 85 to 100%. The circularity is measured using a circumference measuring device (laser-based). The hardness of a filter segment is preferably 75 to 100%. The hardness of a filter segment is measured using a hardness meter (FQA and so forth) as the amount of deformation when a constant load of 300 gf is applied.

(Manufacturing Method for Filter Segment)

A manufacturing method for a filter segment according to the present invention is not particularly limited, and the filter segment may be manufactured using a manufacturing apparatus for a filter segment 40 illustrated in Fig. 4, for example. First, a fiber bundle 41 is supplied, from a fiber dispenser, typically in the form of a bale 42 of compressed fibers. The fiber bundle 41 is stretched using compressed air and cylinders and then relaxed in a strand processing unit 43. As a result, the fiber bundle 41 is spread to incorporate more air therein. Subsequently, the fiber bundle 41 is wet with a second plasticizer. For example, a predetermined amount of second plasticizer can be added uniformly to the fiber bundle 41 by spraying the second plasticizer uniformly onto the entire fiber bundle 41. Later, the fiber bundle 41 is passed through a funnel-shaped insertion member 44 for pre-compression of the fiber bundle 41. The insertion member 44 is usually provided with an opening for easy discharge of excess air within the fiber bundle 41. A breakable capsule feeder 46 is disposed downstream of the insertion member 44, and one or more breakable capsules are embedded in the fiber bundle 41 by the breakable capsule feeder 46.
Fig. 5 illustrates an enlarged view of a portion around a breakable capsule feeder. A breakable capsule feeder 50 illustrated in Fig. 5 is equipped with a rotatable disk-shape insertion wheel 53 having a plurality of breakable capsule feeding pockets 55 arranged at regular intervals on the circumference. Each breakable capsule feeding pocket 55 can hold a breakable capsule 54. In a fiber bundle guide 52, breakable capsules 54 held in the breakable capsule feeding pockets 55 of the insertion wheel 53 are continuously embedded at regular intervals in the fiber bundle that has passed through an insertion member 51. Here, before breakable capsules 54 are embedded in the fiber bundle, a first plasticizer 57 is supplied to the breakable capsules 54 and the rim of the insertion wheel 53 by a first plasticizer feeder 56. The first plasticizer feeder 56 can attach the first plasticizer 57 to the surface of each breakable capsule 54 and the rim of the insertion wheel 53, for example, by spraying the first plasticizer 57. The first plasticizer feeder 56 may spray the first plasticizer 57 toward the interface between the insertion wheel 53 and each breakable capsule 54.
By supplying a first plasticizer in advance to breakable capsules and the rim of an insertion wheel by a first plasticizer feeder as in the foregoing, when the breakable capsules are embedded in a fiber bundle, as illustrated in Fig. 6, for example, a first plasticizer 62 attached to the surface of each breakable capsule 61 and the rim of an insertion wheel 63 is attached and diffused to fibers 60 located near the breakable capsule 61 and the insertion wheel 63. Consequently, the first plasticizer attached to the surface of the breakable capsule is attached to fibers located around the breakable capsule to fuse the breakable capsule and the fibers located around the breakable capsule. Moreover, the first plasticizer attached to the surface of the breakable capsule diffuses to fibers located around the breakable capsule and forms a cocoon-like first hardened structure of the fibers fused together by the first plasticizer to cover the perimeter of the breakable capsule. Further, the first plasticizer attached to the rim of the insertion wheel diffuses to fibers that come into contact with the rim of the insertion wheel, in other words, fibers located near axis A as well as to fibers located in a portion extending from axis A to the periphery of the filter segment, thereby forming a rib-like second hardened structure of the fibers fused together by the first plasticizer.
Subsequently, as illustrated in Fig. 4, the fiber bundle 41 is introduced into a wrapper unit 48 and wrapped in a filter wrapper. Here, the filter wrapper is introduced into an adhesive feeding unit 47 before supplied to the wrapper unit 48, and an adhesive is applied to a portion of the side edge where the filter wrapper is to be overlapped and stuck together after being formed into a filter segment, in other words, to a margin for a glue. The fiber bundle 41 wrapped in the filter wrapper is formed into a continuous bar by passing through the wrapper unit 48. Finally, the fiber bundle 41 wrapped in the filter wrapper is cut with a rotary cutting head 49 to yield filter segments. Fig. 7 illustrates a schematic horizontal cross-sectional view of continuous fibers before cutting with a rotary cutting head. The fibers 70 illustrated in Fig. 7 are wrapped in a filter wrapper 71. Around a breakable capsule 72, a cocoon-like first hardened structure 73 is formed to cover the breakable capsule 72. Moreover, a second hardened structure 74 is continuously provided almost parallel to the axial direction (horizontal direction in Fig. 7) of the fibers 70. Filter segments are obtained by cutting the fibers 70 along dotted line regions at regular intervals. Here, any cigarette paper or filter wrapper manufactured by papermaking companies may be used as the filter wrapper, and in particular, 35NFB or 50NFB (trade name, from Nippon Paper Papylia Co., Ltd.) may be used therefor.

[Tobacco Products]

A tobacco product according to the present invention includes a tobacco-containing segment and a filter segment according to the present invention. A tobacco product according to the present invention, which includes a filter segment according to the present invention, can suppress the displacement of a breakable capsule even when an external force is applied thereto.
Exemplary tobacco products include: cigarettes, such as common cigarettes, cigars, hand-rolled cigarettes, and cigarillos; non-combustion-heating tobacco products, such as tobacco products (electronic cigarettes) in which tobacco flavor is inhalable through heating of tobacco using a heater or the like or through steaming of tobacco and tobacco products in which tobacco flavor is inhalable through heating of tobacco using a carbon heat source or the like; and tobacco products in which tobacco flavor is inhalable without heating.

(Cigarettes)

Hereinafter, embodiments of a cigarette as an exemplary tobacco product according to the present invention will be described. As illustrated in Fig. 8, a cigarette 80 includes: a tobacco-containing segment 81 that contains tobacco shreds 83 (shredded leaves, tobacco) and a cigarette paper 84 wrapped around the tobacco shreds 83; and a filter segment 82 according to the present invention that is provided adjacent to the tobacco-containing segment 81. The tobacco-containing segment 81 and the filter segment 82 are connected by a tipping paper 85 wrapped around the tobacco-containing segment 81 and the filter segment 82. The tipping paper 85 may have vent holes on part of the outer perimeter. The number of vent holes may be one or more, and 10 to 40 vent holes may be formed, for example. When the number is more than one, a plurality of vent holes are arranged, for example, aligning in a row or on a ring on the outer perimeter of the tipping paper 85. A plurality of vent holes may be arranged at almost constant intervals. Through vent holes formed, air is taken into the filter segment 82 during inhalation. By diluting mainstream smoke with external air from vent holes, it is possible to design a product having a desirable tar value.
A user can enjoy tobacco flavor by igniting the tip of the tobacco-containing segment 81 and inhaling with the mouth end of the filter segment 82 in the mouth. By rupturing a breakable capsule on this occasion, mainstream smoke is mixed with a flavor in liquid contents of a breakable capsule, thereby imparting the intended flavor in the oral cavity of the user. In the present invention, the movement of a breakable capsule is suppressed when rupturing the breakable capsule. Consequently, a user can easily rupture the breakable capsule at a desirable timing and enjoy the altered flavor as a result.
In addition to a filter segment containing a breakable capsule according to the present invention, a tobacco product according to the present invention may further include at least one or more second filter segments. For example, a cigarette 90 illustrated in Fig. 9 includes a second filter segment 92 between a tobacco-containing segment 91 and a filter segment 93 according to the present invention. Such a second filter segment 92 may be different from or the same as the filter segment 93 according to the present invention except for lacking a breakable capsule. Since the second filter segment 92 can be functionalized differently from the filter segment 93 according to the present invention, it is possible to impart a plurality of functions to the filter.

(Non-combustion-heating Tobacco Products)

Embodiments of a non-combustion-heating tobacco product as another exemplary tobacco product according to the present invention will be described. Non-combustion-heating tobacco products belong to the field of so-called electronic cigarettes in which a tobacco-containing segment is heated by an electric heater or the like. Fig. 10 illustrates an exemplary non-combustion-heating tobacco system including a tobacco product according to the present invention, which is a non-combustion-heating tobacco product, and a heating device for heating the tobacco product. Fig. 10 is a cross-sectional view of a tobacco product 100 and a heating device 101 cut on a plane containing central axis C.
The non-combustion-heating tobacco system illustrated in Fig. 10 includes: a heating device 101 having a battery 106, an electric heating section 107, and a recess 108; and a tobacco product 100 to be detachably inserted into the recess 108 of the heating device 101. The recess 108 is formed as a depression on part of a case 109 for the heating device 101. The battery 106 can be charged and discharged. The electric heating section 107 is a so-called heater and includes a heating element provided to surround the recess 108. The heating element of the electric heating section 107 heats a tobacco-containing segment 102 to release a flavor from the filler of the tobacco-containing segment 102 to the surrounding air. The heating temperature of the tobacco-containing segment 102 by the electric heating section 107 is 400°C or lower, for example, which is lower than the burning temperature (700°C to 800°C) of heated tobacco products. By heating at a low temperature like this, the amount of mainstream smoke generated from the tobacco-containing segment 102 is smaller than that of heated tobacco products. For this reason, the amount of mainstream smoke supplied to the mouth of a user becomes favorable when the filtering function of the filter segment (104, 105) is lower than the filtering function of a filter segment in heated tobacco products. In other words, the length in the axial direction of the filter segment (104, 105) is preferably shorter than the length in the axial direction of a filter segment in heated tobacco products. It is also possible to shorten the length in the axial direction of the filter segment (104, 105) and dispose a tubular section or another segment having a low filtering rate of mainstream smoke in the corresponding portion.
The tobacco product 100 is cylindrical and includes: a tobacco-containing segment 102 that contains tobacco and an aerosol former for generating an aerosol upon heating; a tubular segment 103 provided adjacent to the tobacco-containing segment 102; a second filter segment 104 provided adjacent to the tubular segment 103; and a first filter segment 105 according to the present invention that is provided adjacent to the second filter segment 104. The tobacco-containing segment 102, the tubular segment 103, the second filter segment 104, and the first filter segment 105 are connected by a tipping paper 110.
The tobacco-containing segment 102 includes: a tobacco filler 111 containing tobacco and an aerosol former; and a cigarette paper 112 wrapped around the tobacco filler. As tobacco, tobacco shreds (shredded leaves, tobacco), tobacco sheet shreds, a folded or rolled tobacco sheet, or a pleated and gathered tobacco sheet may be used, for example. Exemplary aerosol formers include glycerol, propylene glycol, triethyl citrate, and 1,3-butanediol. The cigarette paper 112 may be paper alone or paper stuck together with a metal foil having satisfactory thermal conductivity, such as aluminum foil or stainless steel foil.
The tubular segment 103 is cylindrically formed from 100 to 300 µm-thick cardboard, for example, to have predetermined rigidity. The tipping paper 110 is supported by the rigid tubular segment 103. Consequently, crushing of the tipping paper 110 in the direction of central axis C is suppressed even when the tobacco product 100 is pressed in the direction of central axis C. The tipping paper 110 and the tubular segment 103 have a plurality of vent holes 113 on part of the outer perimeters. A plurality of vent holes 113 penetrate through the tipping paper 110 and the tubular segment 103. The number of the vent holes 113 may be 10 to 40, for example. A plurality of vent holes 113 are arranged, for example, aligning in a row or on a ring on the tubular outer perimeter. A plurality of vent holes 113 may be arranged at constant intervals.
The second filter segment 104 may be different from or the same as the first filter segment 105 except for lacking a breakable capsule. Although one second filter segment 104 is provided between the tubular segment 103 and the first filter segment 105 in Fig. 10, two or more second filter segments 104 may be provided. In this case, two or more second filter segments 104 may be the same or different from each other. The second filter segment 104 and the first filter segment 105 are connected by a second filter wrapper 114.
A user can enjoy a flavor of the tobacco product 100 in the oral cavity through inhalation via the first filter segment 105 while the tobacco product 100 remains inserted into the heating device 101 or after detaching the tobacco product 100 from the heating device 101. Since the tobacco product 100 includes the first filter segment 105 according to the present invention, it is possible to suppress the movement of a breakable capsule and thus improve the ease in rupturing the breakable capsule as well as the convenience of a user. Since the amount of mainstream smoke is small in the tobacco product 100, in particular, the length in the axial direction of the first filter segment 105 tends to be short. Even when the length of the first filter segment 105 is short, however, it is possible in the present invention to satisfactorily suppress the movement of a breakable capsule. In the tobacco product 100 having a short first filter segment 105 like this, in which a breakable capsule could possibly be forced outside from the inside of the first filter segment 105, effectively suppressing the movement of a breakable capsule is useful in designing products.

EXAMPLES

Hereinafter, the present invention will be described further specifically by means of working examples. The present invention, however, is by no means limited by these examples.

(1) Physical Property Evaluation

[Example 1]

(Preparation of Filter Segment)

A filter segment containing breakable capsules was prepared using the manufacturing apparatus for a filter segment 40 illustrated in Fig. 4 (machine speed: 500 fpm). A fiber bundle 41, which is a cellulose acetate fiber bundle (5.9Y35, target tow mass: 0.636 g/filament), was supplied in the form of a bale 42 of compressed fibers from a fiber dispenser. In the strand processing unit 43, the fiber bundle 41 was stretched using compressed air and cylinders, relaxed, and then uniformly added with triacetin (hereinafter, also referred to as TA) as a second plasticizer through spraying onto the fiber bundle 41. Triacetin was added aiming at the content of triacetin as a second plasticizer of 6 mass% relative to fibers.
The fiber bundle 41 was passed through the insertion member 44, and then, breakable capsules were disposed in the fiber bundle 41 by the breakable capsule feeder 46. As a breakable capsule, an almost spherical capsule of 3.5 mm in diameter in which a mixture of a medium-chain triglyceride, menthol, and a plant essential oil as a flavor is covered with a shell containing gellan gum, oxidized starch, and calcium chloride was used. The breakable capsule feeder 46 was equipped with an insertion wheel having a plurality of breakable capsule feeding pockets arranged on the circumference. Triacetin as a first plasticizer was sprayed onto the rim of the insertion wheel by the first plasticizer sprayer 45. In this example, triacetin was sprayed at 7 g/min aiming at the content of triacetin as a first plasticizer of 1 mass% relative to fibers.
The sprayed triacetin was attached to the surface of each breakable capsule and the rim of the insertion wheel. Consequently, triacetin attached to the surface of each breakable capsule fused the breakable capsule and cellulose acetate fibers present around the breakable capsule. Fig. 11 shows a magnified image of this fusion. Moreover, triacetin attached to the surface of each breakable capsule diffused to cellulose acetate fibers present around the breakable capsule to form, around the breakable capsule, a cocoon-like first hardened structure of cellulose acetate fibers fused together by triacetin. Fig. 12 is a magnified image showing the formation of such a cocoon-like first hardened structure. In Fig. 12, the magnified image was taken after removing the breakable capsule for convenience. Further, triacetin attached to the rim of the insertion wheel of the breakable capsule feeder 46 diffused to cellulose acetate fibers that came into contact with the rim of the insertion wheel, in other words, cellulose acetate fibers located near axis A as well as to cellulose acetate fibers located in a portion extending from axis A to the periphery of the filter segment, thereby forming a rib-like second hardened structure of cellulose acetate fibers fused together by triacetin.
Subsequently, the fiber bundle 41 was introduced into the wrapper unit 48 and wrapped in a filter wrapper (trade name: 50NFB, from Nippon Paper Papylia Co., Ltd.). The filter wrapper was introduced into the adhesive feeding unit 47 before supplied to the wrapper unit 48, and an adhesive was applied to a portion of the side edge where the filter wrapper is to be overlapped and stuck together after being formed into a filter segment, in other words, to a margin for a glue. The fiber bundle 41 wrapped in the filter wrapper was passed through the wrapper unit 48 and formed into a continuous bar. Finally, the bar was cut with the rotary cutting head 49 to yield a cylindrical contiguous filter segment of 120 mm in length in the long axis direction containing eight breakable capsules, in other words, a filter segment consisting of contiguous eight filter segments of 15 mm. Table 1 shows target values for the respective physical properties of the contiguous filter segment, and Table 2 shows the evaluation results. The respective physical properties were evaluated by the following methods.
In Example 1, two contiguous filter segments were prepared using the manufacturing apparatus 40 for quantifying each first and second plasticizer. In other words, a contiguous filter segment containing triacetin as a second plasticizer was prepared using the manufacturing apparatus 40 by uniformly adding triacetin as a second plasticizer through spraying without operating the first plasticizer sprayer 45 of the manufacturing apparatus 40 or without spraying triacetin as a first plasticizer. Subsequently, a contiguous filter segment containing triacetin as first and second plasticizers was prepared by operating the first plasticizer sprayer 45 of the manufacturing apparatus 40 or spraying triacetin as a first plasticizer without changing other settings of the manufacturing apparatus 40. The former contiguous filter segment was used as a sample for quantifying triacetin as a second plasticizer. The latter contiguous filter segment was used as a sample for quantifying triacetin as first and second plasticizers. The quantification result of triacetin as a first plasticizer in Example 1 was obtained as a difference between the quantification results of triacetin for the latter and the former contiguous filter segments.

(Physical Property Evaluation)

< Triacetin Content >

By using a contiguous filter segment containing capsules as a sample, the triacetin content in the filter segment was calculated as a percentage of the mass of triacetin to the mass of filter fibers contained in the contiguous filter segment. The mass of filter fibers was weighed using a precise balance. The mass of triacetin was quantified by gas chromatography (from Agilent Technologies, Inc.). An extract of triacetin subjected to quantification was obtained by immersing a sample in 25 mL ethanol (GR-grade) containing 1 mg/3 mL of anethole as an internal standard, shaking at 200 ± 10 reciprocations/min for 20 minutes, leaving overnight, and shaking again for 20 minutes. Triacetin was quantified by subjecting 1 µL of the extract to a gas chromatograph equipped with a flame ionization detector and extrapolating the acquired data to a calibration curve similarly obtained using eight standard solutions of the triacetin concentrations within the range of 0.020 mg/mL to 5.000 mg/mL. The series of measurements by weighing and quantifying were repeated two to three times, and the respective calculated results were averaged as the triacetin content.

< Circularity >

The circularity of a cross-section perpendicular to the axial direction of a filter segment was measured by the roundness measuring function of a laser-based circumference measuring device (RL-2200 (trade name) noncontact roundness tester from Mitutoyo Corporation).

< Pressure Drop (PD) >

The pressure drop (PD) of a filter segment was measured using a pressure drop meter in accordance with ISO 6565: 2015.

< Coefficient of Variation for Pressure Drop (PD CV) >

The coefficient of variation for pressure drop (PD CV) was calculated by dividing the standard deviation for measured pressure drop by the mean.

< Hardness >

The hardness of a filter segment was calculated as a percentage of the diameter before and after applying, with an indenter, a load of 300 gf to the filter segment using a Rockwell hardness tester.

[Example 2]

A contiguous filter segment was prepared in the same manner as Example 1 except for spraying triacetin at 14 g/min aiming at the content of triacetin as a first plasticizer relative to fibers of 2 mass%, and the physical properties were evaluated similarly. The results are shown in Tables 1 and 2.

[Example 3]

A contiguous filter segment was prepared in the same manner as Example 1 except for spraying triacetin at 21 g/min aiming at the content of triacetin as a first plasticizer relative to fibers of 3 mass%, and the physical properties were evaluated similarly. The results are shown in Tables 1 and 2.

[Example 4]

A contiguous filter segment was prepared in the same manner as Example 1 except for changing the target tow mass to 0.580 g/filament, and the physical properties were evaluated similarly. The results are shown in Tables 1 and 2.

[Example 5]

A contiguous filter segment was prepared in the same manner as Example 3 except for changing the target tow mass to 0.580 g/filament, and the physical properties were evaluated similarly. The results are shown in Tables 1 and 2.

[Comparative Example 1]

A contiguous filter segment was prepared in the same manner as Example 1 except for omitting the spraying of triacetin as a first plasticizer by the first plasticizer sprayer, and the physical properties were evaluated similarly. The results are shown in Tables 1 and 2.

[Comparative Example 2]

A contiguous filter segment was prepared in the same manner as Example 4 except for omitting the spraying of triacetin as a first plasticizer by the first plasticizer sprayer, and the physical properties were evaluated similarly. The results are shown in Tables 1 and 2.

[Table 1]

	Target value
	Tow mass (g/filament)	First plasticizer content (mass%)	Second plasticizer content (mass%)	PD (mmH₂O)	Length in axial direction (mm)	Circumference (mm)
Ex. 1	0.636	1	6	305	120	23.7
Ex. 2	0.636	2
Ex. 3	0.636	3
Ex. 4	0.580	1
Ex. 5	0.580	3
Comp. Ex. 1	0.636	0
Comp. Ex. 2	0.580	0

[Table 2]

	Evaluation results
	Tow mass (g/filament)	First plasticizer content (mass%)	Total content of first and second plasticizers (mass%)	Addition efficiency of first plasticizer (%)	PD (mmHzO)	PD CV (-)	Length in axial direction (mm)	Circumference (mm)	Circularity (%)	Hardness (%)
Ex. 1	0.662	0.96	6.47	45.1	321.6	2.4	120.3	23.7	96.9	97.93
Ex. 2	0.654	1.02	6.53	24.0	320.4	2.5	120.3	23.7	96.8	98.04
Ex. 3	0.661	0.83	6.34	13.0	322.7	1.9	120.3	23.7	96.9	97.96
Ex. 4	0.601	0.46	6.84	19.4	253.0	2.5	120.3	23.8	96.4	96.52
Ex. 5	0.598	0.98	7.36	13.8	252.8	2.3	120.3	23.7	96.6	96.41
Comp. Ex. 1	0.658	0	5.51	-	320.8	2.1	120.3	23.7	96.7	97.60
Comp. Ex. 2	0.591	0	6.38	-	253.3	2.7	120.3	23.8	96.3	96.16

As shown in Tables 1 and 2, the filter segments of Examples 1 to 5 added with triacetin as a first plasticizer exhibited physical properties comparable to the filter segments of Comparative Examples 1 and 2, to which triacetin as a first plasticizer was not added. Accordingly, it was confirmed that the local addition of a first plasticizer separately from uniform addition of a second plasticizer does not affect the physical properties of a filter segment.

[Example 6]

A contiguous filter segment was prepared in the same manner as Example 2, and the mass of triacetin (total mass of triacetin as a first plasticizer and triacetin as a second plasticizer) was quantified for a zone near a breakable capsule, in other words, a zone of 5 mm width containing a breakable capsule (capsule neighboring zone) as well as a zone adjacent to the breakable capsule neighboring zone (adjacent zone) to determine the mass% of triacetin in filter fibers. The results are shown in Table 3.

[Comparative Example 3]

A contiguous filter segment was prepared in the same manner as Example 2 except for omitting the spraying of triacetin as a first plasticizer by the first plasticizer sprayer, and the mass of triacetin (total mass of triacetin as a first plasticizer and triacetin as a second plasticizer) was quantified for a zone near a breakable capsule, in other words, a zone of 5 mm width containing a breakable capsule (capsule neighboring zone) as well as a zone adjacent to the breakable capsule neighboring zone (adjacent zone) to determine the mass% of triacetin in filter fibers. The results are shown in Table 3.

[Table 3]

		Repeat number	Triacetin content (mass%)	Average triacetin content (mass%)
Ex. 6	Capsule neighboring zone	1	6.13	6.57
	Capsule neighboring zone	2	7.01	6.57
	Adjacent zone	1	5.81	6.25
	Adjacent zone	2	6.69	6.25
Comp. Ex. 3	Capsule neighboring zone	1	4.90	5.08
	Capsule neighboring zone	2	5.25	5.08
	Adjacent zone	1	4.82	5.03
	Adjacent zone	2	5.24	5.03

As is evident from Table 3, the average triacetin concentration in a zone near a breakable capsule (capsule neighboring zone) was comparable to that in a zone adjacent to the breakable capsule neighboring zone (adjacent zone) in Comparative Example 3. Meanwhile, the average triacetin concentration in a zone near a breakable capsule (capsule neighboring zone) was 1.05 times or more of that in a zone adjacent to the breakable capsule neighboring zone (adjacent zone) in Example 6.

(2) Displacement Evaluation

[Example 7]

(Preparation of Contiguous Filter Segment)

Cellulose acetate fibers of 3.5Y35 were used. A mixture of 99 mass% of triacetin (TA) and 1 mass% of cellulose acetate (CA) was used as a first plasticizer. The first plasticizer was sprayed aiming at the first plasticizer content of 3.0 ± 1.5 mass% relative to filter fibers of the entire filter segment. Except for these, a filter segment was prepared in the same manner as Example 1 to yield a contiguous filter segment in which breakable capsules of 3.5 mm in diameter were embedded at intervals of 15 mm.

(Evaluation of Breakable Capsule Displacement)

Noticeable displacement was evaluated using a pinch tester for a breakable capsule contained in a filter segment that is located at the end of a contiguous filter segment (hereinafter, also referred to as terminal filter segment). Specifically, as illustrated in Fig. 14, the boundary between the terminal filter segment 142 of 15 mm in length in the axial direction and the second filter segment 141 of 15 mm in length in the axial direction adjacent to the terminal filter segment 142 was pinched by pressing with pinching members 143 of the pinch tester. After the end of pinching, the contiguous filter segment was moved by 1 mm in the sending direction 144 to shift the pinching position by 1 mm to the terminal side and then pinched again. These steps were repeated 11 times.
The rebound stress from the terminal filter segment 142 was measured from the strain produced in the pinching members 143. Here, a case in which the breakable capsule 140 of the terminal filter segment 142 was moved by 3.0 mm or more at the end of the test was evaluated as noticeable displacement. These evaluations were made for 30 contiguous filter segments to determine the rate of noticeable displacement, maximum stress position when the central position of the breakable capsule 140 at the start of the test is set to 0 mm, maximum stress, and average stress. The results are shown in Table 4.

[Example 8]

A contiguous filter segment was prepared in the same manner as Example 7 except for using triacetin (TA) as a first plasticizer, and the displacement evaluation was made similarly. The results are shown in Table 4.

[Example 9]

A contiguous filter segment was prepared in the same manner as Example 7 except for adding the second plasticizer aiming at the plasticizer content of 9 mass% relative to fibers, and the displacement evaluation was made similarly. The results are shown in Table 4.

[Example 10]

A contiguous filter segment was prepared in the same manner as Example 8 except for adding the second plasticizer aiming at the plasticizer content of 9 mass% relative to fibers, and the displacement evaluation was made similarly. The results are shown in Table 4.

[Comparative Example 4]

A contiguous filter segment was prepared in the same manner as Example 7 except for omitting the addition of the first plasticizer, and the displacement evaluation was made similarly. The results are shown in Table 4.

[Comparative Example 5]

A contiguous filter segment was prepared in the same manner as Example 9 except for omitting the addition of the first plasticizer, and the displacement evaluation was made similarly. The results are shown in Table 4.

[Comparative Example 6]

A contiguous filter segment was prepared again in the same manner as Comparative Example 5, and the displacement evaluation was made similarly. The results are shown in Table 4.

[Table 4]

	Second plasticizer content (target value) (mass%)	First plasticizer	First plasticizer content (mass%)	Rate of noticeable displacement (%)	Maximum stress position (mm)	Maximum stress (N)	Average stress (N)
Ex. 7	6	TA+CA	1.8	30	-4.5 to -3.5	15.4 (+1.1)	14.3
Ex. 8	6	TA	4.3	23	-7.5 to -1.5	14.6 (+1.0)	13.6
Ex. 9	9	TA+CA	3.1	0	-3.5 to -1.5	16.5 (+1.8)	14.7
Ex. 10	9	TA	4.3	0	-6.5 to -3.5	15.8 (+1.5)	14.3
Comp. Ex. 4	6	-	0	100	-7.5	13.7	13.7
Comp. Ex. 5	9	-	0	77	-7.5	15.2	15.2
Comp. Ex. 6	9	-	0	77	-7.5	14.8	14.7

As shown in Table 4, the terminal filter segments of Examples 7 to 10 added with the first plasticizer exhibited a lower rate of noticeable displacement of a breakable capsule than the terminal filter segments of Comparative Examples 4 to 6, to which the first plasticizer was not added. In other words, the displacement of a breakable capsule was suppressed in Examples 7 to 10 even when an external force is applied thereto.
Moreover, the maximum stress was measured at a position on the breakable capsule side of the start position of the test (-7.5 mm) in Examples 7 to 10. Meanwhile, the maximum stress was measured at the start position of the test in Comparative Examples 4 to 6. Since the movement of the breakable capsule was suppressed in Examples 7 to 10, the stress gradually increased from the start position of the test and decreased after reaching the maximum stress to rupture the breakable capsule at a reduced number of pinching. Meanwhile, since the breakable capsule was moved by every pinching in Comparative Examples 4 to 6, the stress slightly and gradually decreased from the start position of the test without rupturing the breakable capsule by pinching.
Further, the maximum stress value was significantly larger than the average stress value in Examples 7 to 10. Meanwhile, the maximum stress value was comparable to the average stress value in Comparative Examples 4 to 6. Since the movement of the breakable capsule was suppressed in Examples 7 to 10, the stress was larger before rupturing the breakable capsule and the maximum stress value was significantly larger than the average stress value. Meanwhile, since the breakable capsule was moved by every pinching in Comparative Examples 4 to 6, the stress slightly and gradually decreased from the start position of the test without significant changes and the maximum stress value was almost comparable to the average stress value.

REFERENCE SIGNS LIST

10: Filter segment
11: Filter
12: Breakable capsule

Claims

A filter segment for a tobacco product, comprising
a filter containing fibers and

a breakable capsule embedded in the filter to be located on the central axis of the filter segment, wherein the filter segment has

a first hardened structure that is formed of the fibers located near the breakable capsule and fused together by a plasticizer to cover the breakable capsule or

a second hardened structure that is formed of the fibers located near the central axis of the filter segment and fused together by the plasticizer.
The filter segment according to Claim 1, having the first hardened structure and the second hardened structure.
The filter segment according to Claim 1 or 2, wherein the breakable capsule and the fibers are fused by the plasticizer.
The filter segment according to any one of Claims 1 to 3, wherein the fibers extend almost parallel to the axial direction of the filter segment.
The filter segment according to any one of Claims 1 to 4, wherein the plasticizer is at least one compound selected from the group consisting of triethyl citrate, acetyl triethyl citrate, dibutyl phthalate, diallyl phthalate, diethyl phthalate, dimethyl phthalate, bis(2-methoxyethyl) phthalate, dibutyl tartrate, ethyl o-benzoylbenzoate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, N-ethyltoluenesulfonamide, triacetin, o-cresyl p-toluenesulfonate, triethyl phosphate, triphenyl phosphate, and tripropionin.
The filter segment according to Claim 5, wherein the plasticizer is triacetin.
The filter segment according to any one of Claims 1 to 6, wherein the surface of the breakable capsule is formed from at least one compound selected from the group consisting of starch, dextrin, polysaccharides, agar, gellan gum, gelatin, natural gelling agents, glycerol, sorbitol, and calcium chloride.
The filter segment according to any one of Claims 1 to 7, wherein the fibers are cellulose acetate fibers.
The filter segment according to any one of Claims 1 to 7, wherein a plasticizer content relative to the filter of the entire filter segment is 5 to 15 mass%.
The filter segment according to any one of Claims 1 to 9, wherein the length in the axial direction of the filter segment is 5 to 15 mm.
The filter segment according to any one of Claims 1 to 10, wherein the breakable capsule is almost spherical in shape.
The filter segment according to Claim 11, wherein the breakable capsule has a diameter of 1.0 to 3.5 mm.
The filter segment according to Claim 12, wherein the plasticizer content (mass%) in a zone of 5 mm width with the breakable capsule at the center is, in the axial direction of the filter segment, 1.05 times or more of the plasticizer content (mass%) in a zone adjacent to the zone.
The filter segment according to any one of Claims 1 to 13, wherein
the filter segment is cylindrical, and

the plasticizer content (mass%) within a cylindrical region having the central axis of the filter segment at the center and having a dimeter of 75% length of the diameter of the filter segment is higher than the plasticizer content (mass%) in the filter segment outside the cylindrical region.
The filter segment according to Claim 14, wherein the plasticizer content within the cylindrical region is 5 to 20 mass%, and the plasticizer content in the filter segment outside the region is 3 to 8 mass%.
The filter segment according to any one of Claims 1 to 15, wherein the second hardened structure extends from the central axis of the filter segment to the periphery of the filter segment.
The filter segment according to Claim 16, wherein
the filter segment is cylindrical, and

the plasticizer content (mass%) inside a cylindrical region having the central axis of the filter segment at the center and having a diameter of 75% length of the diameter of the filter segment and inside a fan-shaped columnar region having a central angle of 30° to 90° and radially extending from the central axis to the periphery of the filter segment is higher than the plasticizer content (mass%) in the filter segment outside the cylindrical region and the fan-shaped columnar region.
The filter segment according to Claim 17, wherein
the plasticizer content inside the cylindrical region and the fan-shaped columnar region is 5 to 20 mass%, and the plasticizer content in the filter segment outside the cylindrical region and the fan-shaped columnar region is 3 to 8 mass%.
A tobacco product comprising a tobacco-containing segment and the filter segment according to any one of Claims 1 to 18.
The tobacco product according to Claim 19, comprising at least one or more second filter segments between the tobacco-containing segment and the filter segment.
The tobacco product according to Claim 19 or 20, wherein the tobacco product is a cigarette.
The tobacco product according to Claim 19 or 20, wherein the tobacco product is a non-combustion-heating tobacco product.
The tobacco product according to Claim 22, wherein the tobacco-containing segment comprises tobacco and an aerosol former.