Paper lid

Abstract

[Problem] A top plate can be molded into a shape raised upward, that is, a dome-like shape, and moreover, leakage of contents through wrinkles is effectively suppressed. [Solution] A paper lid 1 includes a top plate portion 11, an enclosed portion 12, an outer extension portion 13, an inner fitting portion 14, a peak portion 15, and an outer fitting portion 16. A lower side portion 14a continuous with the outer extension portion 13 in the inner fitting portion 14 has wrinkles 27 extending in an up-down direction formed over a whole circumference on an inner surface of the lower side portion 14a. The lower side portion 14a is contactable with a container-portion inner peripheral surface of a paper container 2 when the paper container 1 is fitted.

Description

TECHNICAL FIELD

[0001] The present invention relates to a paper lid.BACKGROUND ART

[0002] Resin lids made of plastic or the like are used as lids of paper containers, such as paper cups. However, when discarding the resin lids, it is necessary to separate them from the paper cups or the paper containers, which is troublesome for consumers. In particular, a reduction in resin usage and a reduction in CO 2 are desired as a countermeasure for global warming, and the resin lids have been being increasingly replaced by the paper lids.

[0003] Lids can be generally divided roughly into two kinds that are ones with a top plate in a flat planar lid shape and ones with a top plate raised upward. Among them, while the planar lid shape is applied to a type of beverage that is drunk with a straw, for example, cold beverages, a shape with a top plate raised upward, that is, a dome-like shape is often applied to a type of beverage that is directly drunk from a container to a mouth, for example, hot beverages, or a type of beverage having a topping, such as cream.

[0004] Patent Document 1 describes a paper lid in a planar lid shape. With this paper lid disclosed in Patent Document 1, a container can be freely fitted by an annular recess portion formed by an inner fitting portion, a peak portion, and an outer fitting portion provided on an outer peripheral side of a top plate. However, this paper lid has a configuration in which the top plate gets into an inner surface side of the container, and has a configuration in which the annular recess portion is raised higher than this top plate. In view of this, there has been a problem of difficulty in applying the paper lid for the type of beverage that is directly drunk from a container to a mouth, for example, hot beverages, or the type of beverage having a topping, such as cream.

[0005] Such a paper lid is manufactured by drawing molding, and a compressive force applied to paper during this drawing molding generates wrinkles. When these wrinkles are generated to extend across the peak portion from the inner fitting portion, the contents within the container leak out through the wrinkles. No paper lid has been invented that can effectively suppress the leakage of the contents through such wrinkles in the current circumstances.

[0006] Furthermore, after the paper undergoes drawing molding, the paper lid discharged from a metallic mold has a dimensional change in a direction in which an outer periphery of the paper lid increases as a result of the wrinkles formed during the molding attempting to recover. Even though it is attempted to close the container with the paper lid having such a dimensional change, a fitting force is reduced. Accordingly, a technique has also been conventionally desired that can effectively suppress the dimensional change of the paper lid outer periphery due to the wrinkle recovery after the molding.

[0007] Patent Document 1: Japanese Patent No. 6978606DISCLOSURE OF THE INVENTIONPROBLEMS TO BE SOLVED BY THE INVENTION

[0008] Therefore, the present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a paper lid that can be molded into a shape with a top plate raised upward, that is, a dome-like shape, and moreover, that can effectively suppress leakage of contents through wrinkles. In addition, an object of the present invention is to provide a paper lid that can effectively suppress leakage of contents through wrinkles, and furthermore, that can effectively suppress a dimensional change of a paper lid outer periphery due to wrinkle recovery after molding.SOLUTIONS TO THE PROBLEMS

[0009] A paper lid made of paper fitted to a paper container according to the present invention includes a top plate portion, an enclosed portion, an outer extension portion, an inner fitting portion, a peak portion, and an outer fitting portion. The enclosed portion is provided along an outer periphery of the top plate portion, is extended to a lower side, and is continuous with the top plate portion. The outer extension portion is provided along an outer periphery of the enclosed portion, is extended to an outer side, and is continuous with the enclosed portion. The inner fitting portion is provided along an outer periphery of the outer extension portion, is extended to an upper side, and is continuous with the outer extension portion. The peak portion is provided along an outer periphery of the inner fitting portion, is extended to the outer side, and is continuous with the inner fitting portion. The outer fitting portion is provided along an outer periphery of the peak portion, is extended to the lower side, and is continuous with the peak portion. A lower side portion continuous with the outer extension portion in the inner fitting portion has wrinkles extending in an up-down direction formed over a whole circumference on an inner surface of the lower side portion, and the lower side portion is contactable with a container-portion inner peripheral surface of the paper container when the paper container is fitted.

[0010] A paper lid made of paper fitted to a paper container according to the present invention includes a top plate portion, an inner fitting portion, a peak portion, and an outer fitting portion. The inner fitting portion is provided on an outer peripheral side with respect to the top plate portion and is extended to an upper side. The peak portion is provided along an outer periphery of the inner fitting portion, is extended to an outer side, and is continuous with the inner fitting portion. The outer fitting portion is provided along an outer periphery of the peak portion, is extended to a lower side, and is continuous with the peak portion. Continuous wrinkles are formed over a whole circumference on at least an inner surface from at least the inner fitting portion to the outer fitting portion via the peak portion. The outer fitting portion has a bend portion bending to the outer side.

[0011] A paper lid made of paper fitted to a paper container according to the present invention includes a top plate portion, an inner fitting portion, a peak portion, and an outer fitting portion. The inner fitting portion is provided on an outer peripheral side with respect to the top plate portion and is extended to an upper side. The peak portion is provided along an outer periphery of the inner fitting portion, is extended to an outer side, and is continuous with the inner fitting portion. The outer fitting portion is provided along an outer periphery of the peak portion, is extended to a lower side, and is continuous with the peak portion. Continuous wrinkles are formed over a whole circumference on at least an inner surface from at least the inner fitting portion to the outer fitting portion via the peak portion. The outer fitting portion has a bend portion bending to an inner side.EFFECTS OF THE INVENTION

[0012] With the present invention having the above-described configuration, a top plate can be molded into a shape raised upward, that is, a dome-like shape, and the lower side portion continuous with the outer extension portion in the inner fitting portion is made contactable with the container-portion inner peripheral surface of the paper container when the paper container is fitted, thereby allowing leakage of contents through the wrinkles to be effectively suppressed.

[0013] The present invention having the above-described configuration can effectively suppress leakage of contents through the wrinkles, and moreover, can effectively suppress a dimensional change of a paper lid outer periphery due to wrinkle recovery after molding.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Fig. 1(a) is a schematic plan view illustrating an exemplary paper lid according to one embodiment of this invention. Fig. 1(b) is a schematic cross-sectional view taken along the line IB-IB in Fig. 1(a). Fig. 2 is a schematic cross-sectional view to show an enlarged view inside the broken-line frame II in Fig. 1(b). Fig. 3 is a drawing illustrating an example in which a lower side portion is expanded in diameter toward an outer side in an inner fitting portion, and an upper side portion positioned higher than the lower side portion is extended to an upper side in an approximately identical diameter. Fig. 4(a) is a schematic perspective view illustrating an exemplary paper lid according to one embodiment of this invention. Fig. 4(b) is a schematic perspective view showing the schematic perspective view shown in Fig. 4(a) a part of which is cut out. Fig. 5(a) is a cross-sectional view in a depth direction on the paper surface in Fig. 2 in the inner fitting portion. Fig. 5(b) is a cross-sectional view illustrating an example of narrowing wrinkles by compressing them to an inner side in a circumferential direction. Fig. 6 is an enlarged view of a contacting portion between the inner fitting portion and a container-portion inner peripheral surface of a paper container. Fig. 7 is a drawing illustrating results of verifying the presence / absence of leakage of the contents of the paper container through a wrinkle without any treatment and through a wrinkle compressed in the circumferential direction. Fig. 8 is a drawing illustrating results of verifying the presence / absence of leakage of contents with respect to the heights of the inner fitting portion. Fig. 9 is a drawing illustrating results of verifying the degree of leakage of contents for examples in which a compressive force is increased by adding a press load. Fig. 10(a) illustrates an example in which a bend portion bending to an outer side of an outer fitting portion is formed. Fig. 10(b) is an enlarged view of a region surrounded by the dotted line in Fig. 10(a). Fig. 11(a) is a drawing illustrating an example in which the bend portion is not formed on the outer side of the outer fitting portion. Fig. 11(b) is a drawing illustrating an example in which the bend portion is formed on the outer side of the outer fitting portion. Fig. 12 is a drawing for describing a formation position of the bend portion. Fig. 13 is drawings illustrating examples of forming a bend portion bending to an inner side in the outer fitting portion. Fig. 14 is a schematic cross-sectional view illustrating an exemplary processing machine usable for manufacturing the paper lid according to one embodiment of the present invention. Fig. 15 is drawings for describing a method for drawing molding a top plate portion and an enclosed portion by using the processing machine. Fig. 16 is drawings for describing a method for drawing molding an outer extension portion, the inner fitting portion, a peak portion, and the outer fitting portion by using the processing machine. Fig. 17 is drawings for describing a method for drawing molding a curled portion by using the processing machine. Fig. 18 is a drawing for describing a method for drawing molding by pressing down a first side holder in a moving-down direction with a tapered surface being formed. Fig. 19 is a drawing illustrating an example of measuring the paper thicknesses of the paper lid actually molded on the basis of the drawing molding method. Fig. 20 is drawings for describing a method for molding the bend portion bending to the outer side in the outer fitting portion. Fig. 21 is a drawing for describing another method for molding the bend portion bending to the outer side in the outer fitting portion. Fig. 22 is a drawing for describing a method for molding the bend portion bending to the inner side in the outer fitting portion. DESCRIPTION OF PREFERRED EMBODIMENTS

[0015] The following describes embodiments of a paper lid to which the present invention is applied in detail with reference to the drawings.(Paper Lid)

[0016] Fig. 1(a) is a schematic plan view illustrating an exemplary paper lid according to one embodiment of this invention. Fig. 1(b) is a schematic cross-sectional view taken along the line IB-IB in Fig. 1(a). Fig. 2 is a schematic cross-sectional view to show an enlarged view inside the broken-line frame II in Fig. 1(b).

[0017] As illustrated in Fig. 1(a), Fig. 1(b), and Fig. 2, a paper lid 1 is formed of a blank 10 mainly made of paper, and includes a top plate portion 11, an enclosed portion 12, an outer extension portion 13, an inner fitting portion 14, a peak portion 15, an outer fitting portion 16, and a curled portion 17. The shape of the paper lid 1 in plan view is, for example, a circle. Hereinafter, in Figs. 1 and 2, an outer side (a direction X1) refers to an outward direction with a paper container 2 made of, for example, a paper cup to be fitted as the center, a lower side (a direction X2) refers to a downward direction when the paper container 2 is placed via a bottom surface, and an upper side (a direction X3) refers to an upward direction when the paper container 2 is placed via the bottom surface. However, these lower side (the direction X2) and upper side (the direction X3) are not limited to a perfectly vertically downward direction and vertically upward direction, and also include a obliquely downward direction displaced from the vertically downward direction and a obliquely upward direction displaced from the vertically upward direction.

[0018] As the paper lid 1, portions that function essentially as a lid, that is, serve a function of preventing the contents within the paper container 2 from scattering or leaking are the top plate portion 11 and the enclosed portion 12, and the remaining outer edge portion OEP (the outer extension portion 13, the inner fitting portion 14, the peak portion 15, the outer fitting portion 16, and the curled portion 17) functions to be fitted to the paper container 2.

[0019] The top plate portion 11 is extended toward the outer side (the direction X1). The top plate portion 11 has a top surface 11a and a container surface 11b. The container surface 11b is on the back side of the top surface 11a. The container surface 11b faces a container portion of the paper container 2 when the paper lid 1 is fitted to the paper container 2.

[0020] The enclosed portion 12 is provided along an outer periphery of the top plate portion 11, and is extended to the lower side (the direction X2) with respect to the top plate portion 11. This enclosed portion 12 is configured to be continuous with the top plate portion 11. At this time, the enclosed portion 12 may be molded to have a diameter gradually expanded toward the lower side, in other words, to incline toward the outer side in side cross-sectional view. The continuous portion between the enclosed portion 12 and the top plate portion 11 may be molded into a rounded streamline shape. The enclosed portion 12 formed by such a configuration enables closing the lid at a position where the top plate portion 11 is separated from the paper container 2. These top plate portion 11 and enclosed portion 12 enable molding into a shape raised upward, that is, a dome-like shape, which is applicable to a type of beverage that is directly drunk from a container to a mouth, for example, hot beverages, or a type of beverage having a topping, such as cream.

[0021] The outer extension portion 13 is provided along an outer periphery of the enclosed portion 12 in the outer edge portion OEP of the paper lid 1, and is extended toward the outer side (the direction X1). This outer extension portion 13 is configured to be continuous with the enclosed portion 12. The extension width of this outer extension portion 13 is not particularly limited, and may be designed to have a size such that the inner fitting portion 14 can be in contact with a container-portion inner peripheral surface 21 of the paper container 2 when the paper container 2 is fitted as described later.

[0022] The inner fitting portion 14 is provided along an outer periphery of the outer extension portion 13 in the outer edge portion OEP of the paper lid 1, and is extended toward the upper side (the direction X3). This inner fitting portion 14 is configured to be continuous with the outer extension portion 13. While the inner fitting portion 14 may be raised until reaching the peak portion 15 in an approximately identical diameter, in other words, toward an approximately vertical direction in cross-sectional view, it is not limited to this, and may have a diameter gradually expanded toward the outer side until reaching the peak portion 15. As illustrated in Fig. 3, the inner fitting portion 14 may have a lower side portion 14a expanded in diameter toward the outer side, and have an upper side portion 14b, which is positioned higher than the lower side portion 14a, extended upward in an approximately identical diameter.

[0023] The peak portion 15 is provided along an outer periphery of the inner fitting portion 14 in the outer edge portion OEP of the paper lid 1, and is extended toward the outer side (the direction X1). This peak portion 15 is configured to be continuous with the inner fitting portion 14. The peak portion 15 includes a curved surface that forms a convex toward the upper side (the direction X3) on its cross-sectional surface.

[0024] The outer fitting portion 16 is provided along an outer periphery of the peak portion 15 in the outer edge portion OEP of the paper lid 1, and is extended toward the lower side (the direction X2). This outer fitting portion 16 is configured to be continuous with the peak portion 15. The outer fitting portion 16 is separated from and opposed to the inner fitting portion 14. An annular recess portion 20 that uses each of the inner fitting portion 14 and the outer fitting portion 16 as a surrounding wall and the peak portion 15 as a bottom is provided under the peak portion 15 and between the inner fitting portion 14 and the outer fitting portion 16. The annular recess portion 20 is fitted to the paper container 2. At this time, the inner fitting portion 14 is fitted to the container-portion inner peripheral surface 21 of the paper container 2, and the outer fitting portion 16 is fitted to an outer peripheral surface of a curled portion 28 of the paper container 2.

[0025] The curled portion 17 is provided along a circumferential direction of the outer fitting portion 16 in the outer edge portion OEP. The curled portion 17 extends to the outer side (the direction X1), and is continuous with the outer fitting portion 16. The curled portion 17 includes an end portion 10a of the paper lid 1. The curled portion 17 may be in a shape curling upward in cross-sectional view, but is not limited to this. Forming such a curled portion 17 allows guiding the paper container 2 to the annular recess portion 20 via this curled portion 17 when the annular recess portion 20 is fitted to the paper container 2.

[0026] That is, the paper lid 1 bends to the lower side (the direction X2) in the enclosed portion 12, bends to the outer side (the direction X1) in the outer extension portion 13, bends to the upper side (the direction X3) in the inner fitting portion 14, bends to the outer side (the direction X1) in the peak portion 15, bends to the lower side (the direction X2) in the outer fitting portion 16, and bends to the outer side (the direction X1) in the curled portion 17 on a cross-sectional surface of the paper lid 1. That is, each of the top plate portion 11, the enclosed portion 12, the outer extension portion 13, the inner fitting portion 14, the peak portion 15, the outer fitting portion 16, and the curled portion 17 is obtained from one piece of the blank 10.

[0027] On the paper lid 1 having such a shape, a boundary between the top plate portion 11 and the enclosed portion 12, a boundary between the enclosed portion 12 and the outer extension portion 13, a boundary between the outer extension portion 13 and the inner fitting portion 14, a boundary between the inner fitting portion 14 and the peak portion 15, a boundary between the peak portion 15 and the outer fitting portion 16, and a boundary between the outer fitting portion 16 and the curled portion 17 may define, for example, inflection points generated by drawing molding the blank 10 or adjacent areas of the inflection points as the respective boundaries.

[0028] Fig. 4(a) is a schematic perspective view illustrating an exemplary paper lid according to one embodiment of this invention. Fig. 4(b) is a schematic perspective view showing the schematic perspective view shown in Fig. 4(a) a part of which is cut out. As illustrated in Fig. 4(a) and Fig. 4(b), at least the outer edge portion OEP (the outer extension portion 13, the inner fitting portion 14, the peak portion 15, the outer fitting portion 16, and the curled portion 17) in the paper lid 1 has wrinkles 27 formed toward the outer side. These wrinkles 27 are naturally generated by a compressive force applied to the blank 10 during this drawing molding. A large number of these wrinkles 27 are present on both the inner surface and the outer surface of the outer edge portion OEP, and are formed over the whole circumference of the paper lid 1.

[0029] Fig. 5(a) is a cross-sectional view in a depth direction on the paper surface in Fig. 2 in the inner fitting portion 14. That is, this cross-sectional view has a circumferential direction of the paper lid 1 in the arrow direction in the drawing. As illustrated in Fig. 5(a), each of the wrinkles 27 is formed to have an interval with one another on an inner surface 31a and an outer surface 31b. These wrinkles 27 may be formed by being compressed toward the inner side in the circumferential direction. That is, the widths of the wrinkles 27 can be narrowed by compressing the wrinkles 27 having relatively wide widths to which no treatment is given indicated by the dotted line in Fig. 5(a) to the inner side in the circumferential direction (the dotted line in Fig. 5(b)) as illustrated in Fig. 5(b). As a result, the void areas of the wrinkles 27 can be reduced. The void area referred to here indicates a cross-sectional area of the wrinkle 27, and can be calculated from a relation between the depth and the width of the wrinkle as illustrated in the drawings. This void area has an image of its cross-sectional surface taken on an optical microscope, and the taken image enables a calculation of the void area.

[0030] Such compression toward the inner side in the circumferential direction of the wrinkles 27 does not necessarily have to be performed from a starting end to a terminating end of the wrinkles 27, and only needs to be performed at least in the inner fitting portion 14. Fig. 6 is an enlarged view of a contacting portion between this inner fitting portion 14 and the container-portion inner peripheral surface 21 of the paper container 2. Bringing the lower side portion 14a in the inner fitting portion 14 into contact with the container-portion inner peripheral surface 21 of the paper container 2 allows fitting to be achieved. At this time, the wrinkles 27 formed in the lower side portion 14a of this inner fitting portion 14 are compressed toward the inner side in the circumferential direction, and thus, leakage of liquid contents within the paper container 2 through these wrinkles 27 can be effectively suppressed.

[0031] Fig. 7 illustrates results of verifying the presence / absence of leakage of the contents of the paper container 2 with respect to the largest void areas through the wrinkles 27 without any treatment (Comparative Example 1) and through the wrinkles 27 compressed in the circumferential direction (Present Invention Example 1). The largest void area referred to here means the cross-sectional area with the largest void area among the cross-sectional areas of the wrinkles 27 that have been measured. In the verification according to the embodiment, the cross-sectional surface of the inner fitting portion 14 was actually cut in the circumferential direction, an image of the cross-sectional surface was taken on an optical microscope, and the largest void area was calculated. The largest void area of Comparative Example 1 was 6741 µm 2< , whereas the largest void area of Present Invention Example 1 was 4359 µm 2< . Note that the contents in this verification are water. In the actual verification, the paper lid 1 is closed on the paper container 2 with the contents filled, thereafter, the paper container 2 is inclined 90° and kept for one minute, and whether leakage is present or not is confirmed.

[0032] In Comparative Example 1 without any treatment, leakage of the contents was confirmed seven seconds after the start of the experiment. In contrast to this, in Present Invention Example 1 having the wrinkles 27 compressed in the circumferential direction, leakage of the contents was not confirmed even after a lapse of one minute. In view of this, the wrinkles 27 are preferred to be compressed in the circumferential direction, and the largest void area is preferred to be 4359 µm 2< .

[0033] According to the present invention, as illustrated in Fig. 6, it is preferred that the lower side portion 14a of the inner fitting portion 14 apply a pressing force to the container-portion inner peripheral surface 21 of the paper container 2 toward the outer side (the direction X1) when being fitted. This causes the wrinkles 27 formed in the lower side portion 14a of the inner fitting portion 14 to be compressed through the pressing on the container-portion inner peripheral surface 21 of the paper container 2, thereby enabling effectively suppressing leakage of the liquid contents within the paper container 2 through the wrinkles 27. Such a pressing force of the lower side portion 14a of the inner fitting portion 14 is added on the basis of the force of the outer extension portion 13 continuous with the inner fitting portion 14 attempting to expand in diameter. This force of the outer extension portion 13 attempting to expand in diameter can also be added, for example, by adjusting a dimension toward the direction X1 of the top plate portion 11 or a diameter expansion width toward the outer side of the enclosed portion 12 in addition to designing a dimension toward the direction X1 of the outer extension portion 13 to be slightly large.

[0034] In order to suppress leakage of the contents within the paper container 2, a height h of the inner fitting portion 14 illustrated in Fig. 6 is preferably set high. Setting the height of the inner fitting portion 14 high enables further enlarging the contact area of the lower side portion 14a of the inner fitting portion 14 in contact with the container-portion inner peripheral surface 21 of the paper container 2, which leads to the suppression of leakage of the contents. In addition to this, setting the height of the inner fitting portion 14 high enables increasing the lengths of the wrinkles 27 in the inner fitting portion 14, thereby enabling increasing the propagation distance of the contents leaking out through the wrinkles 27, which leads to the suppression of leakage of the contents.

[0035] Fig. 8 illustrates results of verifying the presence / absence of leakage of the contents with respect to the heights of this inner fitting portion 14. Comparative Example 2 has a height of the inner fitting portion 14 of 3 mm, Comparative Example 3 has a height of the inner fitting portion 14 of 5 mm, and Present Invention Example 2 has a height of the inner fitting portion 14 of 7 mm. Note that the contents in this verification are water. In the actual verification, the paper lid 1 is closed on the paper container 2 with the contents filled, thereafter, the paper container 2 is inclined 90° and kept for one minute, and whether leakage is present or not is confirmed.

[0036] As a result of the verification, leakage of the contents was confirmed in both Comparative Examples 2 and 3. In contrast to this, in Present Invention Example 2, leakage of the contents was not confirmed. In view of this, it is seen that leakage of the contents through the wrinkles 27 is effectively suppressible by setting the height of the inner fitting portion 14 to 7 mm or more. Note that setting the height of the inner fitting portion 14 to more than 5 mm enables suppressing leakage of the contents similarly to the case of setting the height of the inner fitting portion 14 to 7 mm.

[0037] As illustrated in Fig. 3, expanding the lower side portion 14a in the inner fitting portion 14 in diameter toward the outer side and extending the upper side portion 14b upward in an approximately identical diameter enable effectively adding a press load to the wrinkles 27 in the drawing molding during manufacturing as described in detail later, thereby enabling further compressing the wrinkles 27 from the circumferential direction and each direction. As a result, the contents can be further effectively prevented from leaking out through the wrinkles 27.

[0038] Fig. 9 illustrates results of verifying the degree of leakage of the contents for Present Invention Example 3 without particularly adding a press load in an ordinary way and for Present Invention Example 4 in which a compressive force is increased by adding a press load. The verification was performed by a leakage test (N5), and the contents were hot coffee. Present Invention Example 3 had the largest void area of the wrinkles 27 of 4220 µm 2< , and Present Invention Example 4 had the largest void area of the wrinkles 27 of 2457 µm 2< . In this verification, the paper lid 1 is closed on the paper container 2 with coffee at 85°C filled as contents, thereafter, the paper container 2 is inclined 90° and kept for one minute, and whether leakage is present or not is confirmed. In this verification, determinations were made by regarding a droplet of the contents that has dropped on a desk as "leakage," and regarding the contents that do not drop but is in a state of being accumulated in a gap between the paper container 2 and the paper lid 1 as "bleeding." The leakage is regarded better in performance than the bleeding. For the leakage, a time period that it takes the droplet to drop on the desk is measured.

[0039] As a result of the verification, Present Invention Example 3 had leakage of 4 / 5 (an average of 41.8 seconds) and bleeding of 1 / 5 as a result of the leakage test (N5). In contrast to this, Present Invention Example 4 had leakage of 1 / 5 (50 seconds) and bleeding of 3 / 5. In view of this, it is seen that Present Invention Example 4 has a more improved leakage suppression effect on the contents.

[0040] Forming the wrinkles 27 thus enables the wrinkles 27 to be freely opened in the circumferential direction in addition to the suppression effect on leakage of the contents within the paper container 2, and therefore, the annular recess portion 20 itself can be configured to be freely expandable in diameter. In view of this, the effects described below are also provided.

[0041] While the paper container 2 usually produced has a determined dimension of an outer diameter (an inner diameter), there is a tolerance, and a dimensional difference of approximately 0.5 to 1 mm occurs. Expanding the diameter of the annular recess portion 20 configured to be freely expandable in diameter enables the paper lid 1 to be easily fitted to the paper container 2 even with a small inner diameter. That is, adopting the wrinkles 27 in advance enables preventing extra wrinkles from being additionally formed even when the paper lid 1 is fitted to the paper container 2 with a small inner diameter, and enables preventing the contents from leaking out through the extra wrinkles.

[0042] Note that the present invention is not limited to the embodiment described above. For example, as illustrated in Fig. 10(a), a bend portion 31 bending to the outer side may be formed in the outer fitting portion 16. Fig. 10(b) is an enlarged view of a region surrounded by the dotted line in Fig. 10(a). This bend portion 31 can form a bended shape by folding the outer surface and the inner surface in the outer fitting portion 16 to the outer side with a point P1 as the center, subsequently folding the folded outer surface and inner surface back with a point P2 as the center, and furthermore, folding these folded back outer surface and inner surface at a point P3.

[0043] Such a bend portion 31 is formed to intersect with the wrinkles 27 formed in the outer fitting portion 16. In particular, the wrinkles 27 compressed in the circumferential direction attempt to recover to the original state as illustrated in Fig. 11(a). In contrast to this, forming this bend portion 31 to intersect with the wrinkles 27 enables this bend portion 31 to further inhibit the wrinkles 27 formed by being compressed in the circumferential direction from recovering as illustrated in Fig. 11(b). The wrinkles 27 continue to the inner fitting portion 14, the peak portion 15, and the outer fitting portion 16 forming at least the annular recess portion 20, and therefore, the wrinkles 27 intersecting with the bend portion 31 can be inhibited from recovering to the opposite side of a compression direction until reaching the continuous inner fitting portion 14 via the bend portion 31 formed in the outer fitting portion 16.

[0044] Accordingly, the wrinkles 27 in the inner fitting portion 14 can be inhibited from attempting to recover in the circumferential direction via this bend portion 31, thereby allowing the wrinkles 27 in this inner fitting portion 14 to maintain the state of being compressed in the circumferential direction. As a result, the contents of the paper container 2 can be prevented from leaking out through the wrinkles 27 in this inner fitting portion 14.

[0045] Note that this bend portion 31 has an advantageous effect in that the force of the wrinkles 27 themself attempting to open can be inhibited via the bend portion 31 even when the wrinkles 27 are not compressed toward the inner side in the circumferential direction.

[0046] When the bend portion 31 is provided, the configurations of the enclosed portion 12 and the outer extension portion 13 in a peripheral area of the top plate portion 11 may be omitted. In such a case, the outer periphery of the top plate portion 11 is configured to be directly connected to a lower end of the lower side portion 14a of the inner fitting portion 14.

[0047] This bend portion 31 is preferred to be formed at a position contactable with a lower side of the curled portion 28 at an upper end of the paper container 2 when the paper container 2 is fitted to the annular recess portion 20, for example, as illustrated in Fig. 12. That is, bending this bend portion 31 to the outer side sometimes causes the inner surface 31a folded with P1 as the center to bulge to the inner side. This bulged inner surface 31a enables the curled portion 28 of the paper container 2 to be locked, thereby enabling the paper lid 1 to be fitted in a stable state.

[0048] Note that, in order to fit the paper lid 1 in a stable state, a bend portion 32 that bends to the inner side may be formed in the outer fitting portion 16 as illustrated in Fig. 13(a). The description of the detailed configuration of the bend portion 32 is omitted below as it is similar to that of the bend portion 31. This bend portion 32 is formed at a position contactable with the lower side of the curled portion 28 of the paper container 2 when the paper container 2 is fitted to the annular recess portion 20, for example, as illustrated in Fig. 13(a). This enables the bend portion 32 to lock the curled portion 28 of the paper container 2, thereby enabling the paper lid 1 to be fitted in a stable state. Fig. 13(b) is a drawing illustrating another embodiment of the bend portion 32 bending to the inner side. This embodiment is an example in which the bend portion 32 configured with a triangular cross-sectional surface in Fig. 13(a) is finished into a squashed shape. Via this squashed bend portion 32, the curled portion 28 of the paper container 2 can be more stably locked. Note that the configuration of the curled portion 17 may be omitted in this form, and while the inner fitting portion 14 is disposed upright in the vertical direction, it is not limited to this.

[0049] Next, an exemplary method for manufacturing the paper lid 1 to which the present invention is applied will be described.(Method For Manufacturing Paper Lid 1)<Exemplary Processing Machine>

[0050] Fig. 14 is a schematic cross-sectional view illustrating an exemplary processing machine usable for manufacturing the paper lid according to one embodiment of this invention.

[0051] A processing machine 100 is, for example, a pressing machine. For example, using the processing machine 100 as illustrated in Fig. 14 enables manufacturing the paper lid 1 including the annular recess portion 20 from the blank 10.

[0052] The processing machine 100 includes a drawing die 110, a blank holder 120, a drawing punch 130, a plunger 140, a second side holder 150, and a first side holder 160. Note that a placement table 170 is further provided outside the drawing die 110 and the blank holder 120 in the processing machine 100. Note that Fig. 14 illustrates a cross-sectional shape of this processing machine 100, and such a cross-sectional shape is formed in the circumferential direction.

[0053] In actually manufacturing this paper lid 1 by the processing machine 100, the blank 10 is first placed on a placement surface 142 of the plunger 140, a placement surface 112 of the drawing die 110, and the placement table 170.

[0054] Next, as illustrated in Fig. 15(a), the blank holder 120, the drawing punch 130, and the first side holder 160 are moved in a moving-down direction ZD, and the blank 10 is pressed between them and the drawing die 110, the plunger 140, and the second side holder 150. The drawing die 110, the blank holder 120, the drawing punch 130, the plunger 140, the second side holder 150, and the first side holder 160 are pressed down in the moving-down direction ZD with this blank being pressed. This causes the drawing die 110, the blank holder 120, the drawing punch 130, the plunger 140, the second side holder 150, and the first side holder 160 having the blank 10 interposed therebetween to move down in the moving-down direction ZD in a space surrounded by the placement table 170. As a result, the blank 10 is punched out between the placement table 170 and the blank holder 120, and thus, the blank 10 can be configured into an approximately circular shape in plan view.

[0055] The drawing die 110 has a guide hole 111 and the placement surface 112. The guide hole 111 is, for example, a circular hole. The placement surface 112 is provided outside the guide hole 111. The placement surface 112 faces the blank holder 120. The placement surface 112 is a surface on which the blank 10 can be placed. At an intersection point of the placement surface 112 with the guide hole 111 in the drawing die 110, a curling portion 115 in a round groove shape is provided.

[0056] The blank holder 120 has a guide hole 121 and a pressing surface 122. The guide hole 121 is a circular hole. The pressing surface 122 is provided outside the guide hole 121. The pressing surface 122 faces the placement surface 112. The blank holder 120 presses the blank 10 placed on the placement surface 112. At an intersection point of the guide hole 121 with the pressing surface 122 in the blank holder 120, a curling portion 125 in a round groove shape is provided.

[0057] The drawing punch 130 is movable in each direction of a moving-up direction ZU and the moving-down direction ZD within the guide hole 121. Each of the moving-up direction ZU and the moving-down direction ZD intersects with, for example, is perpendicular to the placement surface 112. The moving-down direction ZD is an opposed direction to the moving-up direction ZU. The drawing punch 130 has a distal end portion on which a punching surface 132 is formed. The punching surface 132 is formed of a flat surface, and presses the blank 10. A first side peripheral surface 131a positioned on a moving-up direction ZU side and a second side peripheral surface 131b positioned on a moving-down direction ZD side are formed in the drawing punch 130.

[0058] The plunger 140 is movable in each direction of the moving-up direction ZU and the moving-down direction ZD within the guide hole 111. The plunger 140 has a distal end portion on which the placement surface 142 is provided. The placement surface 142 faces the punching surface 132. The placement surface 142 has a diameter D1 that is equal to or less than a diameter D2 of the punching surface 132 of the drawing punch 130. A side peripheral surface 141 is formed on the plunger 140.

[0059] The second side holder 150 is movable in each direction of the moving-up direction ZU and the moving-down direction ZD within the guide hole 111 while bringing a side peripheral surface 151 of the second side holder 150 in peripheral contact with the guide hole 111. The second side holder 150 has an upper end where a ring projection portion 152 is formed, and furthermore, a step portion 153 providing a step from a distal end of the ring projection portion 152 toward the lower side is provided outside the ring projection portion 152.

[0060] The first side holder 160 is movable in each direction of the moving-up direction ZU and the moving-down direction ZD within the guide hole 121 while bringing a side peripheral surface 161 of the first side holder 160 in peripheral contact with the guide hole 121. The first side holder 160 has a lower end where a ring projection portion 162 is formed, and furthermore, a step portion 163 providing a step from a distal end of the ring projection portion 162 toward the upper side is provided outside the ring projection portion 162.

[0061] Note that all the movements in the moving-up direction ZU and the moving-down direction ZD of the drawing die 110, the blank holder 120, the drawing punch 130, the plunger 140, the second side holder 150, and the first side holder 160 described above are performed by an air cylinder (not illustrated), but not limited to this, and any other well-known driving means may certainly be used.

[0062] Next, only the drawing punch 130 and the plunger 140 are pressed down in the moving-down direction ZD as illustrated in Fig. 15(b). Meanwhile, a peripheral edge region of the blank 10 is pressed by being sandwiched between the drawing die 110 and the blank holder 120. As a result, the blank 10 stretches in the moving-down direction ZD, and as a result of pushing down a central region of the blank 10, an external shape corresponding to the top plate portion 11 and the enclosed portion 12 is formed.

[0063] Next, as illustrated in Fig. 16(a), the drawing die 110, the blank holder 120, and the first side holder 160 are pressed down in the moving-down direction ZD. This causes the ring projection portion 162 in the first side holder 160 to be fitted to the step portion 153 in the second side holder 150 and the ring projection portion 152 in the second side holder 150 to be fitted to the step portion 163 in the first side holder 160, thus leading to close contact with one another. As a result, the blank 10 is deformed corresponding to the shapes of close contact between these ring projection portion 162 and step portion 153, and ring projection portion 152 and step portion 163, thereby forming an external shape corresponding to the outer extension portion 13 and the inner fitting portion 14 described above. That is, in this process, corresponding to the portion of the ring projection portion 152 in the second side holder 150, the blank 10 is pushed in with the ring projection portion 162 in the first side holder 160 from a region separated from the outside from the outer periphery of the enclosed portion 12, and thus, a shape exactly corresponding to the outer extension portion 13 is formed.

[0064] Next, as illustrated in Fig. 16(b), only the drawing die 110 and the blank holder 120 are moved up in the moving-up direction ZU. As a result, an end portion of the blank 10 is molded in the moving-up direction ZU while being sandwiched between the guide hole 111 of the drawing die 110 and the side peripheral surface 161 of the first side holder 160. As a result, the external shape corresponding to the peak portion 15 and the outer fitting portion 16 is formed. That is, in this process, corresponding to the portion of the step portion 153 in the second side holder 150, the blank 10 is pushed in with the drawing die 110 from the region separated from the outside from the outer periphery of the inner fitting portion 14, and thus, a shape exactly corresponding to the peak portion 15 is formed.

[0065] Next, as illustrated in Fig. 17(a), only the drawing die 110 and the blank holder 120 are moved down in the moving-down direction ZD. Alternatively, the plunger 140, the first side holder 160, the second side holder 150, and the drawing punch 130 are moved up in the moving-up direction ZU. As a result, the end portion of the blank 10 molded in the moving-up direction ZU precisely gets into the curling portion 115 and the curling portion 125 in a round groove shape. The end portion of the blank 10 is disformed along the round groove shapes of the curling portion 115 and the curling portion 125 as the drawing die 110 and the blank holder 120 are gradually moved down, and as a result, the curled portion 17 is formed. This enables manufacturing the paper lid 1 to which the present invention is applied from the blank 10.

[0066] Next, as illustrated in Fig. 17(b), the drawing punch 130 is moved in the moving-up direction ZU, and thus, is separated from the blank 10. Furthermore, the drawing die 110 and the second side holder 150 are moved down in the moving-down direction ZD, and the completed paper lid 1 is carried out.

[0067] With the method for manufacturing the paper lid 1 manufactured by undergoing the above-described process, the molding into a shape raised upward, that is, a dome-like shape made by the top plate portion 11 and the enclosed portion 12, which can be said to be a distinctive portion of the paper lid 1, can be achieved. That is, as illustrated in Fig. 15(b), only the drawing punch 130 and the plunger 140 are moved down to form the shape corresponding to the top plate portion 11 and the enclosed portion 12, and thereafter, the shape of the outer extension portion 13 and the inner fitting portion 14 is formed as illustrated in Fig. 16(a), thereby achieving the molding. After undergoing such a process, as illustrated in Fig. 17(a), the curled portion 17 can be formed via the curling portion 115 and the curling portion 125 in a round groove shape through the pressing down of the drawing die 110 and the blank holder 120 or through the moving up in the moving-up direction ZU of the plunger 140, the first side holder 160, the second side holder 150, and the drawing punch 130, and moreover, these distinctive shapes can be achieved in one cycle by the processing machine 100.

[0068] Note that, in the process of molding the inner fitting portion 14 illustrated in Fig. 16(a) in the present invention, as illustrated in Fig. 18, a tapered surface 162a is provided at a root portion of the ring projection portion 162 in the first side holder 160, and a tapered surface 152a is provided at an upper end adjacent portion in the ring projection portion 152 in the second side holder 150. The tapered surface 162a is configured by only the root portion from the ring projection portion 162 to the step portion 163 being inclined. The tapered surface 152a is configured by only the upper end adjacent portion in the ring projection portion 152 being inclined. Bringing the second side holder 150 and the first side holder 160 into close contact causes these tapered surface 152a and tapered surface 162a to face one another, and the blank 10 interposed between these disform along the inclination of the tapered surface 152a and the tapered surface 162a. As a result, as illustrated in Fig. 3, the form in which the lower side portion 14a is expanded in diameter toward the outer side, and the upper side portion 14b positioned higher than the lower side portion 14a is extended to the upper side in an approximately identical diameter can be molded in the inner fitting portion 14.

[0069] In practice, pressing down the first side holder 160 in the moving-down direction ZD with such tapered surfaces 162a, 152a being formed allows a vector direction of a load to be disassembled to a load vector in a thickness direction of the blank 10 as indicated by the arrow in Fig. 18 from the moving-down direction ZD. As a result, the wrinkles 27 in the blank 10 generated in the process of the drawing molding described above are compressed, and are also compressed toward the inner side in the circumferential direction. As a result, increasing the compressive force on the wrinkles 27 on the basis of the load vector in the thickness direction of the blank 10 enables further reducing the largest void area as described in Present Invention Example 4 illustrated in Fig. 9, thereby enabling strongly suppressing the leakage of the contents.

[0070] Fig. 19 illustrates an example of measuring the paper thicknesses of the paper lid 1 actually molded on the basis of the above-described drawing molding method. The paper thickness increases from the top plate portion 11 to the enclosed portion 12 and the outer extension portion 13, whereas the original paper thickness of the blank 10 is 0.32 mm. This is due to the effect of the wrinkles 27 generated on the basis of the drawing molding, and the paper thickness increases corresponding to the wrinkles 27. Meanwhile, in particular, the lower side portion 14a in the inner fitting portion 14 has a further thinned paper thickness. The paper thickness itself becomes thin as a result of the compressive force being added to the lower side portion 14a in this inner fitting portion 14 in the drawing molding process by pressing down the first side holder 160 in the moving-down direction ZD. At this time, pressing down the first side holder 160 in the moving-down direction ZD in a state where the above-described tapered surfaces 162a, 152a are formed causes the load vector in the thickness direction of the blank 10 to be further applied, and as a result, the paper thickness of this lower side portion 14a decreases, and moreover, the paper thickness itself can be made approximately equal. Furthermore, decreasing the paper thickness with the compressive force in the lower side portion 14a in this inner fitting portion 14 enables hardening the lower side portion 14a itself, and as a result, the pressing force on the container-portion inner peripheral surface 21 of the paper container 2 from the lower side portion 14a of the inner fitting portion 14 is more easily applied, thereby enabling effectively suppressing the leakage of the liquid contents within the paper container 2. The upper side portion 14b and the peak portion 15 other than this lower side portion 14a have thicker paper thicknesses than that of the lower side portion 14a. However, applying a load more to this lower side portion 14a with a thin paper thickness during the drawing molding to avoid applying a load to the other portions with thick paper thicknesses enables preventing the portions from breaking.

[0071] As a result of the compressive force in a paper thickness direction being applied to particularly the lower side portion 14a in the inner fitting portion 14, the compressive force in a depth direction is also applied to the wrinkles 27. As a result, the wrinkles 27 in the lower side portion 14a of the inner fitting portion 14 have the shallowest depths, and the wrinkles of the upper side portion 14b of the inner fitting portion 14, the peak portion 15, and the outer fitting portion 16 have deep depths. Making the wrinkles 27 shallow in the lower side portion 14a of the inner fitting portion 14 enables effectively suppressing the leakage of the liquid contents within the paper container 2 in a similar manner. Note that a similar effect appears as long as the depths of the wrinkles 27 in at least the inner fitting portion 14 are shallower than those in the peak portion 15 and the outer fitting portion 16 irrespective of the lower side portion 14a or the upper side portion 14b.

[0072] When the bend portion 31 bending to the outer side in the outer fitting portion 16 is formed, a drawing die 110' formed in a shape illustrated in Fig. 20(a) is used in a process of forming the curled portion 17 illustrated in Fig. 17(a). For this drawing die 110', Fig. 20(b) illustrates an enlarged region surrounded by the dotted line in Fig. 20(a). In this drawing die 110', an abutting surface 115a on which the end portion 10a of the blank 10 is abuttable is formed in the curling portion 115. In a state where the end portion 10a of the blank 10 is brought into contact with the abutting surface 115a of the curling portion 115, only the drawing die 110 and the blank holder 120 are moved down in the moving-down direction ZD. As a result, a portion corresponding to the outer fitting portion 16 in this blank 10 is compressed from an up-down direction, thereby being naturally bent toward the outer side to form the above-described bend portion 31. At this time, since a round groove is formed in the curling portion 115, the portion corresponding to the outer fitting portion 16 in the blank 10 is compressed from the up-down direction, thereby being naturally bendable to the outer side.

[0073] As illustrated in Fig. 21, further expanding the flat abutting surface 115a of the curling portion 115 enables the end portion 10a of the blank 10 to be easily locked via this abutting surface 115a. Also in such a case, it is preferred that even a slight groove be formed in the curling portion 115 such that the portion corresponding to the outer fitting portion 16 in the blank 10 is bendable to the outer side.

[0074] When the bend portion 32 that bends to the inner side in the outer fitting portion 16 is formed, a first side holder 160' formed in a shape illustrated in Fig. 22 is used in the process of forming the curled portion 17 illustrated in Fig. 17(a). In this first side holder 160', a depressed portion 165 processed into a depressed shape toward the inner side is formed at a position facing the drawing die 110 on the side peripheral surface 161. Forming such a depressed portion 165 causes the portion corresponding to the outer fitting portion 16 in the blank 10 to be compressed from the up-down direction, and to attempt to escape in the depressed portion 165 that is the only portion without the pressing as a result of the end portion 10a of the blank 10 being pressed via the curling portion 125 of the blank holder 120 when only the drawing die 110 and the blank holder 120 are moved down toward the moving-down direction ZD. As a result, the bend portion 32 bending to the inner side can be formed in this depressed portion 165.DESCRIPTION OF REFERENCE SIGNS

[0075] 1: Paper lid 2: Paper container 10: Blank 10a: End portion 11: Top plate portion 11a: Top surface 11b: Container surface 12: Enclosed portion 13: Outer extension portion 14: Inner fitting portion 14a: Lower side portion 14b: Upper side portion 15: Peak portion 16: Outer fitting portion 17, 28: Curled portion 20: Annular recess portion 21: Container-portion inner peripheral surface 27: Wrinkle 31, 32: Bend portion 100: Processing machine 110: Drawing die 111, 121: Guide hole 112: Placement surface 115: Curling portion 115a: Abutting surface 120: Blank holder 122: Pressing surface 125: Curling portion 130: Drawing punch 132: Punching surface 140: Plunger 141, 151, 161: Side peripheral surface 142: Placement surface 150, 160: Side holder 152, 162: Ring projection portion 153, 163: Step portion 165: Depressed portion 170: Placement table OEP: Outer edge portion

Claims

1. A paper lid made of paper fitted to a paper container, comprising: a top plate portion; an enclosed portion that is provided along an outer periphery of the top plate portion, is extended to a lower side, and is continuous with the top plate portion; an outer extension portion that is provided along an outer periphery of the enclosed portion, is extended to an outer side, and is continuous with the enclosed portion; an inner fitting portion that is provided along an outer periphery of the outer extension portion, is extended to an upper side, and is continuous with the outer extension portion; a peak portion that is provided along an outer periphery of the inner fitting portion, is extended to the outer side, and is continuous with the inner fitting portion; and an outer fitting portion that is provided along an outer periphery of the peak portion, is extended to the lower side, and is continuous with the peak portion, wherein a lower side portion continuous with the outer extension portion in the inner fitting portion has wrinkles extending in an up-down direction formed over a whole circumference on an inner surface of the lower side portion, and the lower side portion is contactable with a container-portion inner peripheral surface of the paper container when the paper container is fitted.

2. The paper lid according to claim 1, wherein the wrinkles are formed by being compressed toward an inner side in a circumferential direction.

3. The paper lid according to claim 2, wherein the wrinkle has a void area in cross-sectional view of 4359 µm2 or less.

4. The paper lid according to claim 1, wherein the inner fitting portion has a height of more than 6 mm.

5. The paper lid according to claim 1, wherein the inner fitting portion has the lower side portion expanded in diameter toward the outer side, and an upper side portion positioned higher than the lower side portion extended to the upper side in an approximately identical diameter.

6. The paper lid according to claim 1, wherein the inner fitting portion has the lower side portion pressable on the container-portion inner peripheral surface of the paper container based on a force of the continuous outer extension portion attempting to expand in diameter when the paper container is fitted.

7. The paper lid according to claim 1, wherein the lower side portion of the inner fitting portion has a paper thickness thinner than paper thicknesses of the upper side portion and the outer extension portion.

8. The paper lid according to claim 1, wherein the wrinkles in the inner fitting portion are shallower than wrinkles in the peak portion and the outer fitting portion.

9. A paper lid made of paper fitted to a paper container, comprising: a top plate portion; an inner fitting portion that is provided on an outer peripheral side with respect to the top plate portion and is extended to an upper side; a peak portion that is provided along an outer periphery of the inner fitting portion, is extended to an outer side, and is continuous with the inner fitting portion; and an outer fitting portion that is provided along an outer periphery of the peak portion, is extended to a lower side, and is continuous with the peak portion, wherein continuous wrinkles are formed over a whole circumference on at least an inner surface from at least the inner fitting portion to the outer fitting portion via the peak portion, and the outer fitting portion has a bend portion bending to the outer side.

10. A paper lid made of paper fitted to a paper container, comprising: a top plate portion; an inner fitting portion that is provided on an outer peripheral side with respect to the top plate portion and is extended to an upper side; a peak portion that is provided along an outer periphery of the inner fitting portion, is extended to an outer side, and is continuous with the inner fitting portion; and an outer fitting portion that is provided along an outer periphery of the peak portion, is extended to a lower side, and is continuous with the peak portion, wherein continuous wrinkles are formed over a whole circumference on at least an inner surface from at least the inner fitting portion to the outer fitting portion via the peak portion, and the outer fitting portion has a bend portion bending to an inner side.

11. The paper lid according to claim 9 or 10, wherein the wrinkles are formed by being compressed toward an inner side in a circumferential direction.

12. The paper lid according to claim 11, wherein the wrinkle has a void area in cross-sectional view of 4359 µm2 or less.

13. The paper lid according to claim 9, further comprising: an enclosed portion that is provided along an outer periphery of the top plate portion, is extended to the lower side, and is continuous with the top plate portion; and an outer extension portion that is provided along an outer periphery of the enclosed portion, is extended to the outer side, and is continuous with the enclosed portion, wherein the inner fitting portion is continuous with the outer extension portion, and a lower side portion continuous with the outer extension portion is contactable with a container-portion inner peripheral surface of the paper container when the paper container is fitted.

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