CAPSULE HAVING LIQUID SEALED THEREIN, AND SMOKING ARTICLE PROVIDED WITH SAID CAPSULE

Abstract

 A capsule (22) suitable for a filter cigarette as a smoking article includes: a capsule body (24) that is formed to be elastically deformable in an substantially cylindrical shape, has an end wall (26) closing a front end and an open end (28) opening the other end, and accommodates a liquid thereinside; and a seal member (40) as a blocking wall closing the open end (28), wherein the end wall (26) is formed to be a recessed wall, and includes: an outer peripheral portion (32) provided on an outer periphery; a central portion (34) provided inward of the outer peripheral portion (32) to be more inwardly recessed than the outer peripheral portion (32); and multiple V-shaped grooves(36) radially arranged at the central portion (34) as a thin-walled region, and the bottom thickness of each V-shaped groove (36) is thinner than the thicknesses of the end wall (26) and the peripheral wall (30) of the capsule body (24).

Description

Technical Field

[0001] The present invention relates to a capsule having a liquid enclosed therein suitable for being incorporated in a smoking article, such as a cigarette, a filter cigarette, and a cigar, and also to a smoking article in which the capsule is incorporated.

Background Art

[0002] At the time of smoking, if the above smoking article includes a liquid such as a solution containing water or fragrance thereinside, this contributes to improvement of flavor and taste of mainstream smoke in the smoking article, or enables flavoring of fragrance to the mainstream smoke. In this case, the above described liquid is usually enclosed in a capsule, and is incorporated in the smoking article in a capsule form.

[0003] Prior to smoking, a user breaks the capsule by applying an external force to the capsule from the outside of the smoking article. Such breakage of the capsule allows the liquid to be injected from the capsule into the smoking article, so that the injected liquid is contained in the smoking article.

[0004] If a capsule is formed in a cylindrical shape, and has two end walls, one of the end walls of the capsule is configured to have easy breakability, for example (see FIG. 2 of Patent Document 1). This easy breakability is brought by multiple grooves formed on the one end wall, and these grooves radially extend from a center of the one end wall, for example. When an external force is applied to the capsule, some of the grooves become broken at their bottoms, and the liquid is injected from a broken portion of the grooves into the smoking article.

[0005] There is known a capsule that is formed of two half capsule bodies, and these half capsule bodies are connected to each other via an annular seal (see FIG. 4C of Patent Document 2). When an external force is applied to such a capsule, this capsule is broken at the annular seal, and then the liquid is injected from broken portions of the annular seal into the smoking article.

[0006] Furthermore, there is known a cooling unit that includes a capsule (see FIG. 3 of Patent Document 3). The capsule of this cooling unit includes a coolant enclosed inside the capsule, and a hollow vulnerable projection. If an external force is applied to such a capsule, the projection of the capsule is ruptured, and the coolant is injected from ruptured portions of the projection into the smoking article, thereby extinguishing burning cone of the smoking article.

Prior Art Document

Patent Document

[0007] 

Patent Document 1: Japanese Patent No. 2515794

Patent Document 2: National Publication of International Patent Application No. 2008-528053

Patent Document 3: Japanese Patent Laid-Open No. 2005-318806

Summary of the Invention

Problems to be solved by the Invention

[0008] All the grooves of Patent Document 1, the annular seal of Patent Document 2, and the projection of Patent Document 3 provide easy breakability for the respective capsules to some extent. Unfortunately, breakages of the grooves and the annular seal and the rupture of the projection still require a user for a great external force. Hence, improvement of easy breakability has been required for the capsules of this type.

[0009] Even if the grooves, the annular seal, or the projection is broken or ruptured, a broken or ruptured position thereof cannot be identified in the grooves, the annular seal, or the projection. Consequently, the liquid does not always effectively permeate the smoking article in some cases even if the liquid is injected from the capsule.

[0010] An object of the present invention, which has been made in order to solve the problems according to the conventional art, is to provide a capsule and a smoking article including this capsule that are capable of not only improving easy breakability, but also identifying a broken position thereof.

Means for Solving the Problems

[0011] The above object is attained by a capsule of the present invention, and the capsule comprises: a capsule body formed to be elastically deformable in an substantially cylindrical shape, the capsule body having an end wall that closes a distal end thereof, and an open end that opens a proximal end thereof, the capsule body accommodating a liquid thereinside; and a blocking wall provided at the open end of the capsule body, the blocking wall closing the open end so as to contain the liquid inside the capsule body, wherein the end wall includes: a central portion; an outer peripheral portion in an annular shape, the outer peripheral portion surrounding the central portion, the outer peripheral portion projecting more frontward of the distal end of the capsule body than the central portion so as to form the end wall as a recessed wall; and a thin-walled region provided at the central portion, the thin-walled region having a thinner thickness than thicknesses of the end wall and a peripheral wall of the capsule body.

[0012] According to the above configured capsule, if the peripheral wall of the capsule body is held between user's fingers, for example, and an external force is applied to the peripheral wall, this external force is transferred to the end wall of the capsule body. As aforementioned, the end wall is formed to be a recessed wall, and has the outer peripheral portion projecting more outward than the central portion; thus the external force transferred to the end wall elastically deforms the outer peripheral portion in an elliptical shape. Contrary to this, if the end wall is flat, the end wall is not deformed in an elliptical shape, but simply swells outward of the capsule uniformly in a hemispheric shape.

[0013] If the outer peripheral portion is elastically deformed in an elliptical shape in the aforementioned manner, the thin-walled region of the central portion is greatly tensed toward the both sides of a particular linear portion thereof along the longitudinal axis of the ellipse if viewed from the outer peripheral portion of the elliptical shape. Hence, the particular linear portion in the thin-walled region is tensed, so that the thickness at the center of the particular linear portion is significantly reduced.

[0014] Meanwhile, the external force increases the internal pressure in the capsule, and if the increased internal force is applied to the particular linear portion, the particular linear portion becomes broken at the center thereof whose thickness is reduced; and as a result, the liquid in the capsule is injected from the broken portions.

[0015] The present invention also provides a smoking article incorporating the aforementioned capsule. For example, if the smoking article is a filter cigarette, the capsule of the present invention may be disposed in a filter of the filter cigarette.

[0016] Details and advantageous effects of embodiments according to the capsule of the present invention will be apparent from the accompanying drawings and the description below.

Advantageous Effects of the Invention

[0017] According to the capsule of the present invention, if the external force is applied to the peripheral wall of the capsule body, the outer peripheral portion of the end wall in the capsule body is elastically deformed in an elliptical shape; therefore, it is possible to not only identify a broken position in the thin-walled region, but also significantly improve easy breakability of the capsule.

[0018] According to the smoking article incorporating the above configured capsule of the present invention, it is possible to readily and accurately inject the liquid in the capsule into the smoking article.

Brief Description of the Drawings

[0019] 

FIG. 1 is a sectional view showing a filter cigarette incorporating a capsule, as a smoking article.

FIG. 2 is a perspective view showing a capsule of the first embodiment E1.

FIG. 3 is a longitudinal sectional view of the capsule in FIG. 2.

FIG. 4 is an end elevation view of the capsule in FIG. 2 if viewed from an end wall.

FIG. 5 is a schematic end elevation view explaining how the capsule in FIG. 2 is elastically deformed.

FIG. 6 is a schematic side view of the capsule in FIG. 5.

FIG. 7 is an end elevation view explaining how a capsule having a flat end wall is deformed.

FIG. 8 is a schematic side view of the capsule in FIG. 7.

FIG. 9 is a perspective view showing a capsule of the second embodiment E2.

FIG. 10 is a longitudinal sectional view of the capsule in FIG. 9.

FIG. 11 is an end elevation view of the capsule in FIG. 9 if viewed from the end wall.

FIG. 12 is a perspective view showing a capsule of the third embodiment E3.

FIG. 13 is a longitudinal sectional view of the capsule in FIG. 12.

FIG. 14 is a perspective view showing a capsule of the fourth embodiment E4.

FIG. 15 is a longitudinal sectional view of the capsule in FIG. 14.

FIG. 16 is a graph showing breaking force of each capsule of the first to the fourth embodiments E1 to E4, and breaking force of capsules of a comparative example C and a reference example R, respectively.

Mode for Carrying out the Invention

[0020] FIG. 1 shows a fundamental structure of a filter cigarette 10 according to the present invention, as a smoking article. This filter cigarette 10 comprises a cigarette 12, a composite filter 16 connected to one end of the cigarette 12 through wrapping of a tip paper 14, and the composite filter 16 has a cylindrical shape.

[0021] The composite filter 16 further includes two filter elements 18, 20. Each of these filter elements 18, 19 has a cylindrical shape, and are spaced apart from each other in an axial direction of the cigarette 12. The filter elements 18, 20 are formed of a bunch of filter material, such as acetate fiber and paper, and a wrapping paper for wrapping this bunch. The filter element 18 located on the cigarette 12 side may contain particles of activated carbon or fragrance in the bunch of the filter material.

[0022] The composite filter 16 further includes a capsule 22 of the present invention in which a liquid is enclosed, and the capsule 22 is formed in a substantially cylindrical shape, and is disposed between the filter elements 18, 20. Hence, the capsule 22 has a front end adjacent to the filter element 18 and a rear end adjacent to the filter element 20. The capsule 22 and the filter elements 18, 20 are wrapped with a forming paper (not shown) into the composite filter 16.

[0023] Prior to smoking or during a puff interval of the above configured filter cigarette 10, a user applies an external force F onto the capsule 22 through the tip paper 14, thereby breaking the capsule 22. For example, the capsule 22 is broken at the front end on the filter element 18 side. This breakage of the capsule 22 brings the liquid in the capsule 22 to be injected from a broken position of the capsule 22 into the filter element 18, and then the injected liquid permeates the filter element 18.

[0024] If the liquid in the capsule 22 is water, water soluble components contained in mainstream smoke are solved in the water that has permeated the filter element 18 while the mainstream smoke of the cigarette 12 is passing through the filter element 18, and thus the content of the water soluble components in the mainstream smoke is reduced. As a result, flavor and taste in the mainstream smoke is changed; therefore, the user can enjoy change in flavor and taste.

[0025] Meanwhile, in the case of the liquid containing fragrance, the fragrance is applied to the mainstream smoke; therefore, the user can enjoy this fragrance in addition to the flavor and the taste in the mainstream smoke.

[0026] In addition, the capsule 22 may become broken at the rear end thereof on the filter element 20 side. In this case, when the capsule 22 is broken, the liquid (water) in the capsule 22 permeates the filter element 20. Needless to mention that the same advantageous effect as the aforementioned effect can also be attained if the liquid (water) permeates the filter element 20.

[0027] Various modifications can be made on the aforementioned capsule 22, and specific embodiments of the capsule 22 will be described as below.

[0028] FIG. 2 to FIG. 4 show a capsule 22a of the first embodiment E1.

[0029] A capsule 22a includes a capsule body 24, and the capsule body 24 has a substantially cup shape, and is elastically deformable. Hence, the capsule body 24 has an end wall 26 forming the front end, and an open end 28 of the capsule 22a, respectively.

[0030] Needless to mention that the capsule body 24 has a dimension installable in the composite filter 16. For example, the capsule body 24 preferably has a length of approximately 1 to 3 mm shorter than a length of a cavity 19 that is reserved between the filter elements 18, 20. The capsule body 24 preferably has a diameter of approximately 0.5 to 2 mm smaller than a diameter of each filter element 18, 20, that is, a diameter of the cavity 19.

[0031] The cross section of the capsule body 24 is not limited to a circular shape, and may also be an elliptical shape. In this case, the maximum diameter of the capsule body 24 is set to be approximately 0.5 to 2 mm smaller than the diameter of the cavity 19.

[0032] More specifically, if the cigarette 12 has a diameter of 8 mm, the capsule body 24 has a maximum outer diameter of approximately 6 mm.

[0033] The capsule body 24, that is, the capsule 22a having the above dimension not only facilitates manufacturing of the composite filter 16, that is, installation of the capsule 22a into the filter elements 18, 20, but also facilitates user's awareness of the capsule 22a in the composite filter 16, and also stabilizes the position and the posture of the capsule 22a in the cavity 19.

[0034] The capsule body 24 may be formed of synthetic resin by injection molding, and low density polyethylene (NOVATEC(R) LD manufactured by JAPAN POLYETHYLENE CORPORATION) may be used as this synthetic resin, for example.

[0035] The capsule body 24 further includes a peripheral wall 30. The peripheral wall 30 has an outer diameter, an inner diameter, and a thickness that are slightly but gradually reduced from the open end 28 toward the end wall 26. Strictly speaking, the peripheral wall 30 is tapered.

[0036] As apparent from FIG. 2, the end wall 26 has a recessed wall form. For example, in the first embodiment E1, the end wall 26 includes an annular outer peripheral portion 32, and a central portion 34 that is recessed more inward of the capsule body 24 than the outer peripheral portion 32. As is apparent from FIG. 3, the outer peripheral portion 32 forms an extension of the peripheral wall 30, and projects in the axial direction of the capsule body 24 from the central portion 34 by approximately 0.8 mm, for example. It should be noted that the outer peripheral portion 32 has a greater thickness than the thickness of a front end of the peripheral wall 30 adjacent to the outer peripheral portion 32.

[0037] The central portion 34 does not have an even wall, but has a flat female conical shape if viewed from the outside of the capsule body 24. Hence, the center of the central portion 34 is slightly recessed more inward of the capsule body 24 than the outer periphery of the central portion 34.

[0038] Multiple V-shaped grooves 36 are formed on an inner surface of the central portion 34 as a thin-walled region. These V-shaped grooves 36 are radially arranged around the center of the central portion 34, and are distributed in the peripheral direction of the capsule body 24. Each V-shaped groove 36 extends from the center of the central portion 34 to the outer peripheral portion 32. It should be noted that only one of the V-shaped grooves 36 is shown in FIG. 3.

[0039] An V-shaped angle of each V-shaped groove 36 is 90° for example, a bottom thickness Tv of each V-shaped groove 36 is thinner than the minimum thickness of the end wall 26 and the peripheral wall 30, and may be 0.12 mm, for example. Addition to this, the thickness of the central portion 34 may be 0.3 mm, for example, which is the same as the thickness of the above described outer peripheral portion 32.

[0040] The open end 28 of the capsule body 24 has a flange 38 at its outer periphery, and the flange 38 has a thickness of 0.3 mm, and an outer diameter of 6.4 mm, for example.

[0041] As shown in FIG. 3, the open end 28 is fluid-tightly sealed by a seal member 40. The seal member 40 forms a rear end of the aforementioned capsule 22a. For example, the seal member 40 may be formed of flexible sheet, and is attached to a flange 38 at the open end 28 with an adhesive. If the seal member 40 has such flexibility, the seal member 40 is prevented from hindering elastic deformation of the capsule body 24.

[0042] More specifically, the seal member 40 may be formed of polyamide/ low-density polyethylene laminate sheet (NY#15/DL/LC-21, 50 µm manufactured by TAMAPOLY CO., LTD.). In this case, the seal member 40 is heat-sealed on the flange 38. If the seal member 40 is heat-sealed on the flange 38 in this manner, a greater heat sealing area between the open end 28 and the seal member 40 can be secured, thereby increasing sealing strength of the seal member 40.

[0043] Furthermore, the capsule body 24 includes multiple ribs 42, and these ribs 42 are integrally formed on the outer peripheral surface of the capsule body 24. For example, the ribs 42 extend from the front end of the outer peripheral portion 32 in the end wall 26 to the flange 38 in the axial direction of the capsule body 24, and are disposed with equal intervals in the peripheral direction of the capsule body 24. Addition to this, the thickness of each rib 42 may be approximately 0.3 mm, for example.

[0044] The width of each rib 42 is not constant in the axial direction of the capsule body 24, and is gradually reduced from the flange 38 toward the front end of the outer peripheral portion 32 as apparent from FIG. 4. Hence, stiffness of the capsule body 24 in the radial direction is gradually reduced from the flange 38 toward the end wall 26.

[0045] The capsule body 24 and the seal member 40 form the capsule 22a. The capsule 22a configured in this manner is capable of enclosing a liquid thereinside. For example, the liquid to be enclosed may be distilled water, or a solution formed by dissolving an additive, such as fragrance, in this distilled water.

[0046] The capsule 22a may accommodate a liquid of 130 mg, for example. In the case of disposing the capsule 22a in the composite filter 16, as apparent from the above description of FIG. 1, the capsule 22a is disposed in the cavity 19 between the filter elements 18, 20 in such a manner that the end wall 26 faces the filter element 18 on the cigarette 12 side.

[0047] According to the filter cigarette 10 including the capsule 22a, prior to smoking or during a puff interval, the user holds the capsule 22a in the composite filter 16 between his or her fingers via the tip paper 14 so as to apply the external force F shown in FIG. 1 to the capsule 22a from the both sides in the diameter direction of the capsule 22a.

[0048] While elastically deforming the capsule body 24, this external force F squeezes the capsule body 24, thereby increasing the internal pressure of the capsule 22a.

[0049] The end wall 26 of the capsule body 24 includes the outer peripheral portion 32 as described above, and the outer peripheral portion 32 surrounds the central portion 34 and projects from this central portion 34. Consequently, the end wall 26 has a greater stiffness compared to a flat end wall without having the outer peripheral portion 32. Accordingly, when the external force F is transferred to the end wall 26, the end wall 26 is elastically deformed in an elliptical shape as shown in FIG. 5.

[0050] The elastic deformation at this time applies a tensile strength to the central portion 34 of the end wall 26 as shown by arrows T in FIG. 5. Such a tensile strength T acts on the end wall 26 along the longitudinal axis of the end wall 26 that is deformed in an elliptical shape, and stretches the bottom of the particular V-shaped groove 36 (linear portion) extending along this longitudinal axis, in the groove direction of the particular V-shaped groove. As a result, the bottom thickness of the particular V-shaped groove 36 becomes greatly reduced especially at the center position of the central portion 34.

[0051] While the bottom thickness of the particular V-shaped groove 36 becomes reduced in this manner, if the increased internal pressure of the capsule 22a is applied to the end wall 26, the bottom of the particular V-shaped groove 36 is accurately and readily broken at the center position of the central portion 34, and the liquid in the capsule 22a is injected from broken portion of the V-shaped groove 36 toward the center of the filter element 18. Accordingly, it is possible to improve easy breakability of the capsule 22a, and also possible to identify the broken position of the end wall 26.

[0052] As aforementioned, the central portion 34 is recessed more inward than the outer peripheral portion 32, and is also formed in a flat female conical shape; and furthermore, the V-shaped grooves 36 are formed on the inner surface of the central portion 34. Accordingly, if the end wall 26 is deformed in an elliptical shape, the central portion 34 is further deformed inward of the capsule body 24. This deformation at the central portion 34 greatly increases a groove width of the particular V-shaped groove 36, which encourages breakage of the particular V-shaped groove 36, resulting in further improvement of easy breakability of the capsule 22a.

[0053] After the breakage of the V-shaped groove 36, if the user further pushes the capsule 22a, the liquid in the capsule 22a is continued to be injected from the broken portion of the V-shaped groove 36 toward the filter element 18. Hence, the injected liquid permeates the center of the filter element 18, and, a permeated area LA of the liquid is generated in the filter element 18 as shown in FIG. 1. This permeated area LA stays in the center portion of the filter element 18, so that the liquid injected from the capsule 22a is prevented from wetting the forming paper of the composite filter 16 and the tip paper.

[0054] Providing more detailed description regarding this point, the particular V-shaped groove 36 is broken at the bottom thereof, and once the liquid is injected from the broken portion, the internal pressure in the capsule 22a is rapidly reduced. Thereafter, the broken portion is prevented from becoming enlarged, and the liquid is injected only from the broken portion, that is, from the center of the central portion 34 of the end wall 26 toward the center portion of the filter element 18.

[0055] Meanwhile, the above rapid decrease in internal pressure is perceived by the user through his or her fingers, so that the user can recognize the breakage of the capsule 22a, that is, injection of the liquid.

[0056] If the liquid has permeated the filter element 18, the water soluble components contained in the mainstream smoke becomes dissolved in the liquid, that is, the distilled water in the filter element 18 when the mainstream smoke passes through the filter element 18 as described above. As a result, the water soluble components contained in the mainstream smoke to be actually inhaled by the user is reduced, thereby changing the flavor and the taste in the mainstream smoke.

[0057] Meanwhile, if the liquid contains fragrance, this fragrance is applied to the mainstream smoke, so that the user can enjoy the fragrance at the same time.

[0058] In the first embodiment E1, the peripheral wall 30 of the capsule body 24 is provided with the multiple ribs 42, as aforementioned; thus the peripheral wall 30 has a relatively high stiffness in entirety, but this stiffness of the peripheral wall 30 is gradually reduced from the flange 38 toward the outer peripheral portion 32 of the end wall 26.

[0059] Accordingly, even if the external force F is applied to the capsule body 24 as shown in FIG. 6, the peripheral wall 30 of the capsule body 24 is prevented from being locally recessed, and the external force F is efficiently transferred to the end wall 26 in a flat conical shape. As a result, the end wall 26 is securely deformed into an elliptical shape, and the particular V-shaped groove 36 as the thinner thickness area is readily broken with even the small external force F, as described above.

[0060] FIG. 7 and FIG. 8 respectively show a side view of an end wall 26c in a capsule 23 of a comparative example, and a side view of this capsule 23. In this case, the end wall 26c is flat, and the capsule body 24 of the capsule 23 is not provided with the aforementioned ribs 42.

[0061] When the internal pressure in the capsule 23 is increased by applying the external force F to the capsule 23, the end wall 26c uniformly swells outward of the capsule 23 as shown in FIG. 7 and FIG. 8, without being deformed in an elliptical shape.

[0062] Consequently, the V-shaped groove 36 to be broken is not identified, or even if any of the V-shaped grooves is broken, it is not easy to attain breakage of the capsule at this stage.

[0063] In addition, in the case of the capsule 23 having no ribs 42, the peripheral wall 30 is greatly and locally deformed by the external force F, and thus the external force F is not effectively transferred to the end wall 26c, which makes it difficult to break the V-shaped groove 36.

[0064] The present invention is not limited to the capsule 22a of the above first embodiment E1.

[0065] Hence, the capsule 22 according to the other embodiments will be described hereinafter.

[0066] In the following description of the other embodiments, the same reference numerals are given to the members and portions having the same functions as those in the aforementioned embodiment, and overlapping description will be omitted.

[0067] FIG. 9 to FIG. 11 show a capsule 22b of the second embodiment E2.

[0068] Regarding the structures of the peripheral wall 30 and the end wall 26 of the capsule body 24, the capsule 22b is different from the capsule 22a of the first embodiment E1 in the following points.

[0069] The peripheral wall 30 of the capsule 22b is provided with no aforementioned ribs 42.

[0070] The end wall 26 of the capsule 22b is generally formed to be a recessed wall, as well. However, in the case of the capsule 22b, the outer peripheral portion 32 in a circular shape of the end wall 26 extends radially inward of the capsule body 24. In addition, the central portion 34 of the end wall 26 is formed to be a hemispheric portion 44, and this hemispheric portion 44 is recessed inward of the capsule body 24.

[0071] The center of the hemispheric portion 44 is formed as a thin-walled region 46 in a circular shape, and this thin-walled region 46 has a thickness thinner than the thicknesses of the end wall 26 and the peripheral wall 30 of the capsule body 24. A thickness Tc of the thin-walled region 46 is the same as the aforementioned bottom thickness Tv of each V-shaped groove 36, for example.

[0072] The hemispheric portion 44 includes an annular portion 47 surrounding the thin-walled region 46 between the outer peripheral portion 32 and the thin-walled region 46. This annular portion 47 has a thickness gradually increased from the thin-walled region 46 toward the outer peripheral portion 32, and is connected to an inner corner of the outer peripheral portion 32.

[0073] As apparent from FIG. 10, the outer peripheral portion 32 has a thickness thicker than the outer peripheral thickness of the annular portion 47. The thickness of the peripheral wall 30 is uniform along the axial direction of the capsule body 24, and thicker than the maximum thickness of the peripheral wall 30 in the capsule 22a of the embodiment E1.

[0074] Also in the case of the capsule 22b of the above embodiment E2, when the external force F is applied to the capsule body 24, the end wall 26 of the capsule body 24 is elastically deformed in an elliptical shape. Consequently, a greater tensile force is applied especially to a particular linear portion in the thin-walled region 46 extending along the longitudinal axis of the end wall 26 that is deformed in an elliptical shape; thus the end wall 26 becomes broken at the particular linear portion.

[0075] FIG. 12 and FIG. 13 show a capsule 22c of the third embodiment E3, and FIG. 14 and FIG. 15 show a capsule 22d of the fourth embodiment E4.

[0076] The capsules 22c, 22d of the third and the fourth embodiments E3, E4 are respectively similar to the capsules 22a, 22b of the first and the second embodiments E1 and E2. However, the capsules 22c, 22d are different from the capsules 22a, 22b in that each of the capsules 22c, 22d further includes a projection 48 in a stick form.

[0077] Specifically, in the case of the capsule 22c of the third embodiment E3, the projection 48 projects outward of the capsule body 24 from the center of the central portion 34 of the end wall 26. Meanwhile, in the case of the capsule 22d of the fourth embodiment E4, the projection 48 projects outward of the capsule body 24 from the center of the hemispheric portion 44, that is, the thin-walled region 46.

[0078] In both the third and the fourth embodiments E3, E4, as apparent from FIG. 13 and FIG. 15, a front end surface of the projection 48 and an outer end surface of the end wall 26 (outer peripheral portion 32) are arranged in an identical virtual plane. The diameter and the length of the projection 48 may be approximately 0.4 to 0.5 mm, for example.

[0079] The above projection 48 is useful for determining the broken position when the V-shaped groove 36 or the thin-walled region 46 is broken. Specifically, when the external force F is applied to the capsule body 24 so that the particular V-shaped groove 36 or the particular linear portion in the thin-walled region 46 is tensed, the tensile stress is concentrated on a base of the projection 48. As a result, the projection 48 initiates the breakage, and determines the broken position. The projection 48 does not project outward of the capsule 22 from the end wall 26, which prevents undesired impact from being applied to the projection 48, so that the end wall 26 is unlikely to be broken from the base of the projection 48 in an undesired manner due to such undesired impact.

[0080] FIG. 14 shows each result from measurement of an average breaking force for each of the capsules 22a to 22d of the first to the fourth embodiments at the moment when each capsule 22a to 22d comes broken at the V-shaped groove 36 or in the thin-walled region 46 with the external force F applied to each capsule 22a to 22d. Addition to this, FIG. 14 also shows each result from measurement of an average breaking force for each capsule of a comparative example C and a reference example R.

[0081] In the measurement of the breaking force, a liquid (distilled water) occupying 94% of the capsule volume was filled in each capsule, and a creep meter (RHEONER II (brand name) manufactured by YAMADEN CO., LTD.) was used for the measurement of the breaking force.

[0082] Prior to providing description of the measurement results in FIG. 14, the capsules of the comparative example C and the reference example R will be briefly described herein.

[0083] The capsule of the comparative example C is equivalent to the capsule of Patent Document 1, and the capsule of the reference example R is equivalent to a seamless capsule incorporated in a commercially available filter cigarette.

[0084] As apparent from FIG. 14, the respective breaking forces of the capsules 22a to 22d of the first to the fourth embodiments E1 to E4 are significantly smaller than the breaking force of the capsule of the comparative example C, and their breaking forces are approximate to the breaking force of the capsule of the reference example R. Accordingly, it is appreciated that the capsules 22a to 22d of the first to the fourth embodiments E1 to E4 become broken more easily than the capsule of the comparative example C.

[0085] Comparing the capsules 22a of the first embodiment and the capsule 22c of the third embodiment, both of which are of the same type, to each other, the breaking force of the capsule 22c is smaller than the breaking force of the capsule 22a. Similarly, comparing the capsules 22b of second embodiment and the capsule 22d of the fourth embodiment, both of which are of the same type, to each other, the breaking force of the capsule 22d is smaller than the breaking force of the capsule 22b.

[0086] The above evidence clearly reveals that the above mentioned projection 48 not only determines the breaking position in the end wall 26, but also further facilitates the breakage of the capsules 22c, 22d.

[0087] Finally, the present invention is not limited to the above described first to fourth embodiments E1 to E4.

[0088] For example, the capsule body 24 and the seal member 40 as a blocking wall in the above described embodiments are both formed of low density polyethylene. However, the capsule body and the blocking wall of the present invention may be formed of synthetic resin other than low density polyethylene, and may also be formed of other materials than synthetic resin.

[0089] For example, the capsule body 24 of the first embodiment E1 has the peripheral wall 30 in a tapered shape, which is gradually tapered toward the end wall 26. However, the capsule body of the present invention may also have a peripheral wall in a straight cylindrical shape, or a peripheral wall in a reversely tapered shape.

[0090] The end wall of the capsule body of the present invention may be a recessed wall having a different form than that of the end wall 26 of the above first to the fourth embodiments. For example, in the case of the first and the third embodiments E1, E3, the end wall 26 may have the central portion 34 in a flat shape.

[0091] Furthermore, in the case of the second and the fourth embodiments, the entire of the hemispheric portion 44 may be formed as the thin-walled region, or in the case of the first and the second embodiments, the thin-walled region may be formed as grooves each having a shape other than a V-shape. In addition, arrangements of these grooves are not limited to a radial arrangement.

[0092] Subject to the thin-walled region having a thinner thickness than the thicknesses of the end wall and the peripheral wall of the capsule body, the thin-walled region preferably has a thickness of not less than 0.1 mm and less than 0.2 mm. The thin-walled region more preferably has a thickness of not less than 0.12 mm and less than 0.17 mm.

[0093] For example, each capsule body 24 of the first and the third embodiments E1, E3 has the multiple ribs 42 on its outer peripheral surface. However, these ribs 42 may be provided on an inner peripheral surface of the capsule body 24, or these ribs 42 may also be applicable to an outer peripheral surface or an inner peripheral surface of the capsule body 24 of the second and the fourth embodiments E2, E4.

[0094] The point is that, as far as the capsule of the present invention comprises at least the fundamental structure including the capsule body, the end wall in a recessed shape of the capsule body, the thin-walled region formed in the end wall, and the blocking wall for sealing the open end of the capsule body, the capsule of the present invention may be applicable by appropriately combining other components (also including shapes and arrangements) included in the capsule of each embodiment with the other embodiments.

[0095] Furthermore, needless to mention that the capsule of the present invention may be not only incorporated in a filter cigarette, but also incorporated in various smoking articles.

Explanation of Reference Signs

[0096] 

10

Filter cigarette

14

Tip paper

16

Composite filter

18, 20

Filter element

22, 22a to 22d

Capsule

26

End wall

28

Open end

30

Peripheral wall

32

Outer peripheral portion

34

Central portion

36

V-shaped groove (thin-walled region)

38

Flange

40

Seal member (blocking wall)

42

Rib

44

Hemispheric portion

46

Thin-walled region

48

Projection

Claims

1. A capsule having a liquid enclosed therein,
the capsule comprising:

a capsule body formed to be elastically deformable in an substantially cylindrical shape, the capsule body having an end wall that closes a distal end thereof, and an open end that opens a proximal end thereof, the capsule body accommodating the liquid thereinside; and

a blocking wall provided at the open end of the capsule body, the blocking wall closing the open end so as to contain the liquid inside the capsule body,

wherein

the end wall includes:

a central portion;

an outer peripheral portion in an annular shape, the outer peripheral portion surrounding the central portion, the outer peripheral portion projecting more frontward of the distal end of the capsule body than the central portion so as to form the end wall as a recessed wall; and

a thin-walled region provided at the central portion, the thin-walled region having a thinner thickness than thicknesses of the end wall and a peripheral wall of the capsule body.

2. The capsule according to claim 1, wherein
the thin-walled region has multiple grooves radially arranged at the central portion.

3. The capsule according to claim 2, wherein
the grooves are formed on an inner surface of the central portion.

4. The capsule according to claim 2 or claim 3, wherein
the central portion is recessed inward of the capsule body, and has a flat female conical shape.

5. The capsule according to claim 1, wherein
the central portion is formed as a hemispheric portion that is recessed inward of the capsule body to be in a substantially hemispheric shape, and
the thin-walled region is formed at a center of the hemispheric portion.

6. The capsule according to claim 5, wherein
the thickness of the central portion is gradually increased from the thin-walled region toward the outer peripheral portion.

7. The capsule according to claim 1, wherein
the capsule body further includes multiple ribs that are provided on the peripheral wall, and extend in an axial direction of the capsule body.

8. The capsule according to claim 1, wherein
the capsule body further includes a flange provided at an outer periphery of the open end, and
the blocking wall is a seal member in a sheet form, and is attached to the flange with an adhesive so as to liquid-tightly seal the open end.

9. A smoking article incorporating the capsule according to claim 1.

Drawing