Paper cover

Abstract

The present invention can be molded into a so-called dome shape in which a top plate bulges upward, and can effectively suppress leakage of contents through wrinkles. A paper container (2) is provided with a top plate section (11), a cover section (12), an extension section (13), an inner fitting section (14), a top section (15), and an outer fitting section (16), and a lower portion (14a) of the inner fitting section (14), which is continuous with the extension section (13), is provided with a pleat (27) extending in the vertical direction over the entire circumference of the inner surface thereof, and the lower portion (14a) can be brought into contact with the inner peripheral surface of the container section of the paper container (2) when fitted to the paper container (1).

Description

Technical Field

[0001] The present invention relates to a paper lid. Background Art

[0002] As lids for paper containers such as paper cups, resin lids made of plastics or the like are used. However, resin lids need to be separated from paper cups and paper containers when discarded, which causes trouble for consumers. In particular, as a countermeasure against global warming, reduction of resin usage and CO2 is required, and the switch from resin lids to paper lids is increasing.

[0003] Lids can generally be roughly classified into two types: a flat lid shape with a flat top plate and a shape with a top plate bulging upward. Among them, the flat lid shape is applied to types that are drunk using a straw, such as cold beverages, but the type that is directly drunk into the mouth from the container like hot beverages or the type with ingredients such as cream added often uses a shape like the so-called dome shape where the top plate bulges upward.

[0004] A paper lid with a flat lid shape is described in Patent Document 1. According to the paper lid disclosed in Patent Document 1, the container can be fitted freely through an annular recess formed by an inner fitting portion, a top portion, and an outer fitting portion provided on the outer peripheral side of the top plate. However, this paper lid is configured such that the top plate enters the inner surface side of the container, and the annular recess stands up upward from the top plate. Therefore, there is a problem that it is difficult to apply it to types that are directly drunk into the mouth from the container like hot beverages or types with ingredients such as cream added.

[0005] In addition, such a paper lid is manufactured by deep drawing, but wrinkles are generated due to the compressive force applied to the paper during the deep drawing. When such wrinkles are generated across the inner fitting portion and the top portion, the contents in the container leak through the wrinkles. No paper lid has been proposed that can effectively suppress the leakage of contents through such wrinkles.

[0006] Furthermore, after the paper is deep drawn, the wrinkles formed during molding of the paper lid discharged from the mold recover, and as a result, dimensional changes occur in the direction of expanding toward the outer periphery of the paper lid. Even if one wants to use the paper lid with such dimensional changes to close the container, the fitting force will decrease. Therefore, there has long been a need for a technology that can effectively suppress dimensional changes in the outer periphery of the paper lid due to the recovery of wrinkles after molding.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Patent No. 6978606 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] Therefore, the present invention is proposed in view of the above problems, and its object is to provide a paper lid that can be formed into a so-called dome shape with the top plate bulging upward, and can effectively prevent the contents from leaking through the wrinkles. Another object of the present invention is to provide a paper lid that can effectively prevent the contents from leaking through the wrinkles, and can further effectively prevent the dimensional change of the outer periphery of the paper lid due to the restoration of the wrinkles after molding.

[0012] Means for Solving the Problems

[0013] The paper lid of the present invention is a paper lid made of paper that is fitted to a paper container, and is characterized in that the paper lid has: a top plate portion; a covering portion that is provided along the outer periphery of the top plate portion and extends downward, and the covering portion is continuous with the top plate portion; an outer extension portion that is provided along the outer periphery of the covering portion and extends outward, and the outer extension portion is continuous with the covering portion; an inner fitting portion that is provided along the outer periphery of the outer extension portion and extends upward, and the inner fitting portion is continuous with the outer extension portion; a top portion that is provided along the outer periphery of the inner fitting portion and extends outward, and the top portion is continuous with the inner fitting portion; and an outer fitting portion that is provided along the outer periphery of the top portion and extends downward, and the outer fitting portion is continuous with the top portion. A lower portion of the inner fitting portion that is continuous with the outer extension portion is formed with wrinkles extending in the vertical direction over the entire circumference on its inner surface, and when fitted to the paper container, the lower portion can contact the inner peripheral surface of the container portion of the paper container.

[0014] The paper lid of the present invention is a paper lid made of paper that is fitted to a paper container, and is characterized in that the paper lid has: a top plate portion; an inner fitting portion that is provided at a position on the outer peripheral side of the top plate portion and extends upward; a top portion that is provided along the outer periphery of the inner fitting portion and extends outward, and the top portion is continuous with the inner fitting portion; and an outer fitting portion that is provided along the outer periphery of the top portion and extends downward, and the outer fitting portion is continuous with the top portion. At least a continuous wrinkle is formed over the entire circumference on at least the inner surface from the inner fitting portion through the top portion to the outer fitting portion, and the outer fitting portion is formed with a bent portion that bends outward.

[0015] The paper lid of the present invention is a paper lid made of paper that is fitted to a paper container, and is characterized in that the paper lid has: a top plate portion; an inner fitting portion that is provided at a position on the outer peripheral side of the top plate portion and extends upward; a top portion that is provided along the outer periphery of the inner fitting portion and extends outward, and the top portion is continuous with the inner fitting portion; and an outer fitting portion that is provided along the outer periphery of the top portion and extends downward, and the outer fitting portion is continuous with the top portion. At least a continuous wrinkle is formed over the entire circumference on at least the inner surface from the inner fitting portion through the top portion to the outer fitting portion, and the outer fitting portion is formed with a bent portion that bends inward.

[0016] Advantages of the Invention

[0017] According to the present invention configured as described above, it is possible to form a so-called dome shape in which the top plate bulges upward, and when it is fitted into the paper container, the lower part of the inner fitting part that is continuous with the outer extension part can contact the inner peripheral surface of the container part of the paper container, thereby effectively suppressing the leakage of the content through the wrinkles.

[0018] According to the present invention configured as described above, it is possible to effectively suppress the leakage of the content through the wrinkles, and it is further possible to effectively suppress the dimensional change of the outer periphery of the paper lid due to the restoration of the wrinkles after molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 (a) of is a schematic top view showing an example of a paper lid according to an embodiment of the present invention. Figure 1 (b) of is a schematic cross-sectional view taken along line IB-IB in Figure 1 (a) of.

[0020] Figure 2 is a schematic cross-sectional view showing an enlarged view of the inside of the dashed box II in Figure 1 (a) of.

[0021] Figure 3 is a view showing an example in which the lower part of the inner fitting part expands in diameter toward the outside, and the upper part above the lower part extends upward with substantially the same diameter.

[0022] Figure 4 (a) of is a schematic perspective view showing an example of a paper lid according to an embodiment of the present invention. Figure 4 (b) of is a schematic perspective view showing a part of the schematic perspective view shown in Figure 4 (a) of cut away.

[0023] Figure 5 (a) of is a cross-sectional view of the inner fitting part in Figure 2 in the depth direction of the paper surface. Figure 5 (b) of is a cross-sectional view showing an example in which the wrinkles are narrowed by compressing them inward in the circumferential direction.

[0024] Figure 6 is an enlarged view of the contact portion between the inner fitting part and the inner peripheral surface of the container part of the paper container.

[0025] Figure 7 is a view showing the result of verifying the presence or absence of leakage of the content of the paper container between the wrinkles without any treatment and the wrinkles compressed in the circumferential direction.

[0026] Figure 8 is a view showing the result of verifying the presence or absence of leakage of the content at the height of the inner fitting part.

[0027] Figure 9 It is a figure showing the result of verifying the degree of leakage of the content by applying a stamping load to increase the compressive force.

[0028] Figure 10 (a) of is an example in which a bent portion is formed on the outside of the outer fitting portion. Figure 10 (b) of is Figure 10 An enlarged view of the area surrounded by the dashed line in (a) of.

[0029] Figure 11 (a) of is a figure showing an example in which no bent portion is formed on the outside of the outer fitting portion. Figure 11 (b) of is a figure showing an example in which a bent portion is formed on the outside of the outer fitting portion.

[0030] Figure 12 It is a figure for explaining the formation position of the bent portion.

[0031] Figure 13 It is a figure showing an example in which a bent portion that bends inward is formed in the outer fitting portion.

[0032] Figure 14 It is a schematic cross-sectional view showing an example of a processing machine that can be used for manufacturing a paper lid according to an embodiment of the present invention.

[0033] Figure 15 It is a figure for explaining a method of drawing and forming a top plate portion and a covering portion by using a processing machine.

[0034] Figure 16 It is a figure for explaining a method of drawing and forming an epitaxial portion, an inner fitting portion, a top portion, and an outer fitting portion by using a processing machine.

[0035] Figure 17 It is a figure for explaining a method of drawing and forming a curled portion by using a processing machine.

[0036] Figure 18 It is a figure for explaining a method of drawing and forming by pressing the first cage downward in a state where a conical surface is formed.

[0037] Figure 19 It is a figure showing an example of measuring the paper thickness of a paper lid actually formed based on a drawing and forming method.

[0038] Figure 20 It is a figure for explaining a method of forming a bent portion that bends outward in the outer fitting portion.

[0039] Figure 21 It is a figure for explaining another method of forming a bent portion that bends outward in the outer fitting portion.

[0040] Figure 22 This is a diagram for explaining a method of forming a bent portion that bends inward in the outer fitting portion. Detailed implementation mode

[0041] Hereinafter, an implementation mode of a paper lid to which the present invention is applied will be described in detail with reference to the accompanying drawings.

[0042] (Paper lid)

[0043] Figure 1 (a) of [the paper lid] is a schematic top view showing an example of a paper lid according to an implementation mode of the present invention, Figure 1 (b) of [the paper lid] is a schematic cross-sectional view along Figure 1 the line IB-IB in (a) of [the paper lid]. Figure 2 It is Figure 1 a schematic cross-sectional view showing an enlarged view of the inside of the dashed box II in (a) of [the paper lid].

[0044] As Figure 1 shown in (a) of [the paper lid], Figure 1 (b) of [the paper lid], and Figure 2 as shown, the paper lid 1 is composed of a blank 10 with paper as the main body, and has a top plate portion 11, a covering portion 12, an outer extension portion 13, an inner fitting portion 14, a top portion 15, an outer fitting portion 16, and a curled portion 17. The top view shape of the paper lid 1 is, for example, circular. Hereinafter, in Figure 1 and Figure 2 , the outer side (direction X1) refers to the outer direction centered on a paper container 2 to be fitted, for example, composed of a paper cup, the lower side (direction X2) refers to the lower direction when the paper container 2 is placed with the bottom surface interposed, and the upper side (direction X3) refers to the upper direction when the paper container 2 is placed with the bottom surface interposed. However, these lower side (direction X2) and upper side (direction X3) are not limited to being completely vertically downward and vertically upward, and also include diagonally downward deviated from the vertically downward and diagonally upward deviated from the vertically upward.

[0045] In addition, as the paper lid 1, the top plate portion 11 and the covering portion 12 are responsible for the function of preventing the so-called scattering and leakage of the contents in the paper container 2 as the original lid, and the remaining peripheral edge portion OEP (outer extension portion 13, inner fitting portion 14, top portion 15, outer fitting portion 16, curled portion 17) is responsible for the function of fitting with the paper container 2.

[0046] The top plate portion 11 extends toward the outer side (direction X1). The top plate portion 11 has a top surface 11a and a container surface 11b. The container surface 11b is located on the back surface of the top surface 11a. When the paper lid 1 is fitted with the paper container 2, the container surface 11b faces the container portion of the paper container 2.

[0047] The covering portion 12 is provided along the outer periphery of the top plate portion 11 and extends downward (in the direction X2) from the top plate portion 11. The covering portion 12 is continuously formed with the top plate portion 11. At this time, the covering portion 12 may also be formed to gradually increase in diameter toward the lower side, in other words, to be inclined outward when viewed in a side cross-section. In addition, the continuous portion of the covering portion 12 and the top plate portion 11 may be formed in a streamlined shape with rounded corners. With the covering portion 12 configured in such a form, the top plate portion 11 can be closed at a position separated from the paper container 2. In addition, with the top plate portion 11 and the covering portion 12, it can be formed into a so-called dome shape that bulges upward, and it can also be applied to types such as hot beverages that are directly drunk from the container into the mouth or types with ingredients such as cream added.

[0048] The extending portion 13 is provided along the outer periphery of the covering portion 12 at the peripheral edge portion OEP of the paper lid 1 and extends outward (in the direction X1). The extending portion 13 is continuously formed with the covering portion 12. The extending width of the extending portion 13 is not particularly limited, but it can be dimensioned such that the inner fitting portion 14 can contact the inner peripheral surface 21 of the container portion of the paper container 2 when fitted into the paper container 2, as will be described later.

[0049] The inner fitting portion 14 is provided along the outer periphery of the extending portion 13 at the peripheral edge portion OEP of the paper lid 1 and extends upward (in the direction X3). The inner fitting portion 14 is continuously formed with the extending portion 13. The inner fitting portion 14 may be of substantially the same diameter, in other words, stand upright in a substantially vertical direction in a cross-sectional view until it reaches the top portion 15, but it is not limited thereto, and it may also gradually increase in diameter toward the outside until it reaches the top portion 15. In addition, as Figure 3 shown, the lower portion 14a of the inner fitting portion 14 may increase in diameter toward the outside, and the upper portion 14b above the lower portion 14a extends upward with substantially the same diameter.

[0050] The top portion 15 is provided along the outer periphery of the inner fitting portion 14 at the peripheral edge portion OEP of the paper lid 1 and extends outward (in the direction X1). The top portion 15 is continuously formed with the inner fitting portion 14. The top portion 15 includes a curved surface that bulges upward (in the direction X3) in its cross-section.

[0051] The outer fitting portion 16 is provided along the outer periphery of the top portion 15 at the peripheral edge portion OEP of the paper lid 1 and extends downward (in the direction X2). The outer fitting portion 16 is continuously formed with the top portion 15. The outer fitting portion 16 is opposed to the inner fitting portion 14 separately. Below the top portion 15, an annular recess 20 is provided between the inner fitting portion 14 and the outer fitting portion 16, with the inner fitting portion 14 and the outer fitting portion 16 serving as respective surrounding walls and the top portion 15 serving as the bottom. The annular recess 20 is fitted into the paper container 2. At this time, the inner fitting portion 14 is fitted into the inner peripheral surface 21 of the container portion of the paper container 2, and the outer fitting portion 16 is fitted into the outer peripheral surface of the curled portion 28 of the paper container 2.

[0052] The curled portion 17 is provided along the circumferential direction of the outer fitting portion 16 at the peripheral edge portion OEP. The curled portion 17 extends outward (in the direction X1) and is continuous with the outer fitting portion 16. The curled portion 17 includes the end portion 10a of the paper lid 1. The curled portion 17 may be formed in a shape that curls upward in a cross-section, but is not limited thereto. By forming such a curled portion 17, when the annular recess 20 is fitted to the paper container 2, the paper container 2 can be guided to the annular recess 20 via the curled portion 17.

[0053] That is, in the cross-section of the paper lid 1, the paper lid 1 bends downward (in the direction X2) at the covering portion 12, bends outward (in the direction X1) at the extending portion 13, bends upward (in the direction X3) at the inner fitting portion 14, bends outward (in the direction X1) at the top portion 15, bends downward (in the direction X2) at the outer fitting portion 16, and bends outward (in the direction X1) at the curled portion 17. That is, the top plate portion 11, the covering portion 12, the extending portion 13, the inner fitting portion 14, the top portion 15, the outer fitting portion 16, and the curled portion 17 are respectively obtained from a single blank 10.

[0054] In the paper lid 1 having such a shape, the boundaries between the top plate portion 11 and the covering portion 12, between the covering portion 12 and the extending portion 13, between the extending portion 13 and the inner fitting portion 14, between the inner fitting portion 14 and the top portion 15, between the top portion 15 and the outer fitting portion 16, and between the outer fitting portion 16 and the curled portion 17 can be determined, for example, by taking the inflection points or the vicinity of the inflection points generated by the drawing forming of the blank 10 as their respective boundaries.

[0055] Figure 4 (a) is a schematic perspective view showing an example of a paper lid according to an embodiment of the present invention. Figure 4 (b) is a schematic perspective view showing a part of the schematic perspective view shown in Figure 4 (a) cut away. As shown in Figure 4 (a) and Figure 4 (b), pleats 27 are formed on at least the peripheral edge portion OEP (the extending portion 13, the inner fitting portion 14, the top portion 15, the outer fitting portion 16, the curled portion 17) of the paper lid 1 facing outward. The pleats 27 are naturally generated due to the compressive force applied to the blank 10 during the drawing forming. A plurality of the pleats 27 exist on both the inner surface and the outer surface of the peripheral edge portion OEP and are formed over the entire circumference of the paper lid 1.

[0056] Figure 5 (a) shows a cross-sectional view of the inner fitting portion 14 in the Figure 2 depth direction of the paper surface. That is, in this cross-sectional view, the arrow direction in the figure is the circumferential direction of the paper lid 1. As shown in Figure 5As shown in (a), folds 27 are formed on the inner surface 31a and the outer surface 31b at intervals from each other. The folds 27 can be compressed toward the inner side in the circumferential direction. That is, relative to Figure 5 The relatively wide folds without any treatment shown by the dotted line in (a) can be adjusted by Figure 5 As shown in (b) of Figure 5 The dotted line in (b) is compressed to make it smaller. As a result, the void area of the wrinkle 27 can be reduced. The void area here refers to the cross-sectional area of the wrinkle 27, which can be calculated based on the relationship between the depth and width of the wrinkle as shown in the figure. The void area can be calculated based on the image taken by photographing the cross section under an optical microscope.

[0057] Such compression of the pleats 27 toward the circumferential inner side does not necessarily need to be performed from the starting end to the terminal end of the pleats 27 , and only needs to be performed at least in the inner fitting portion 14 . Figure 6 This is an enlarged view of the contact portion between the inner fitting portion 14 and the inner peripheral surface 21 of the container portion of the paper container 2. The lower portion 14a of the inner fitting portion 14 can be fitted by contacting the inner peripheral surface 21 of the container portion of the paper container 2. At this time, the folds 27 formed in the lower portion 14a of the inner fitting portion 14 are compressed toward the inner side in the circumferential direction, thereby effectively preventing the liquid content in the paper container 2 from leaking along the folds 27.

[0058] Figure 7 The results of verifying the leakage of the contents of the paper container 2 at the maximum gap area between the folds 27 that have not been treated in any way (Comparative Example 1) and the folds 27 that have been compressed in the circumferential direction (Example 1 of the present invention) are shown. The maximum gap area referred to here refers to the largest gap area in the measured cross-sectional area of the folds 27. In the verification of this embodiment, the cross section of the inner fitting portion 14 is actually cut in the circumferential direction, and the cross section is photographed under an optical microscope to calculate the maximum gap area. The maximum gap area of Comparative Example 1 is 6741μm 2 In contrast, the maximum void area of Example 1 of the present invention is 4359 μm 2 In addition, in this verification, the content is water. In the actual verification, the paper cover 1 is placed on the paper container 2 containing the content, and then the paper container 2 is tilted 90 degrees and kept for 1 minute to check whether there is leakage.

[0059] In Comparative Example 1, in which no treatment was performed, leakage of the contents was confirmed 7 seconds after the start of the experiment. In contrast, in Example 1 of the present invention, in which the pleats 27 were compressed in the circumferential direction, leakage of the contents was not confirmed even after 1 minute. Therefore, it is preferred that the pleats 27 be compressed in the circumferential direction, and the maximum void area is preferably 4359 μm 2 .

[0060] In addition, according to the present invention, as Figure 6 shown, preferably during fitting, the lower portion 14a of the inner fitting portion 14 applies a pressing force to the inner peripheral surface 21 of the container portion of the paper container 2 toward the outside (direction X1). As a result, the wrinkles 27 formed in the lower portion 14a of the inner fitting portion 14 are compressed by the pressing against the inner peripheral surface 21 of the container portion of the paper container 2, and as a result, it is possible to effectively suppress the leakage of the liquid content in the paper container 2 along the wrinkles 27. The pressing force of the lower portion 14a of the inner fitting portion 14 is imparted based on the force of the outer extension portion 13 continuous with the inner fitting portion 14 to expand in diameter. Moreover, the force of the outer extension portion 13 to expand in diameter can be imparted not only by, for example, designing the dimension of the outer extension portion 13 in the direction X1 to be slightly larger, but also by adjusting the dimension of the top plate portion 11 in the direction X1 and the expanding width of the covering portion 12 toward the outside.

[0061] In addition, in order to suppress the leakage of the content in the paper container 2, it is preferable to Figure 6 set the height h of the inner fitting portion 14 shown to be relatively high. By setting the height of the inner fitting portion 14 to be relatively high, it is possible to further increase the contact area of the lower portion 14a of the inner fitting portion 14 that contacts the inner peripheral surface 21 of the container portion of the paper container 2, which helps to suppress the leakage of the content. In addition to this, by setting the height of the inner fitting portion 14 to be relatively high, it is possible to extend the length of the wrinkles 27 in the inner fitting portion 14, and as a result, it is possible to extend the propagation distance until the content leaks along the wrinkles 27, which helps to suppress the leakage of the content.

[0062] Figure 8 The results of verifying the presence or absence of leakage of the content at the height of the inner fitting portion 14 are shown. In Comparative Example 2, the height of the inner fitting portion 14 was set to 3 mm, in Comparative Example 3, the height of the inner fitting portion 14 was set to 5 mm, and in Example 2 of the present invention, the height of the inner fitting portion 14 was set to 7 mm. In addition, in this verification, the content was water. In the actual verification, the paper lid 1 was placed on the paper container 2 containing the content, and then the paper container 2 was tilted 90° and held for 1 minute to confirm whether there was leakage.

[0063] As a result of the verification, leakage of the content was confirmed in both Comparative Examples 2 and 3. In contrast, in Example 2 of the present invention, no leakage of the content was confirmed. Therefore, it can be known that by making the height of the inner fitting portion 14 7 mm or more, it is possible to effectively suppress the leakage of the content via the wrinkles 27. In addition, by making the inner fitting portion 14 exceed 5 mm, it is possible to suppress the leakage of the content in the same manner as when it is set to 7 mm.

[0064] In addition, as Figure 3As shown, by expanding the diameter of the lower part 14a in the inner engaging part 14 outward and extending the upper part 14b upward with substantially the same diameter, a stamping load can be effectively applied to the wrinkles 27 during the deep drawing forming in manufacturing as described in detail later. As a result, the wrinkles 27 can be further compressed from the circumferential direction and all directions. As a result, leakage of the content along the wrinkles 27 can be more effectively prevented.

[0065] Figure 9 The results of verifying the leakage degree of the content are shown for the general Example 3 of the present invention without particularly applying a stamping load and Example 4 of the present invention with an increased compression force by applying a stamping load. The verification was carried out through a leakage test (N5), and the content was hot coffee. In addition, the maximum void area of the wrinkles 27 in Example 3 of the present invention was 4220 μm 2 , and the maximum void area of the wrinkles 27 in Example 4 of the present invention was 2457 μm 2 . In this verification, a paper lid 1 was placed on a paper container 2 filled with coffee at 85°C as the content, and then the paper container 2 was tilted 90° and held for 1 minute to confirm whether there was leakage. In addition, in this verification, the situation where the droplets of the content fell on the table was regarded as "leakage", and the situation where the content accumulated in the gap between the paper container 2 and the paper lid 1 but did not fall was regarded as "seepage" for determination. It can be considered that leakage is more excellent in performance than seepage. In addition, regarding leakage, the time until the droplets fell on the table was measured.

[0066] As a result of the verification, the result of the leakage test (N5) of Example 3 of the present invention was that leakage was 4 / 5 (average 41.8 seconds) and seepage was 1 / 5. In contrast, the leakage of Example 4 of the present invention was 1 / 5 (50 seconds) and seepage was 3 / 5. Therefore, it can be known that the leakage suppression effect of the content is improved in Example 4 of the present invention.

[0067] By forming the wrinkles 27 in this way, in addition to the effect of suppressing leakage of the content in the paper container 2, the wrinkles 27 can be freely opened toward the circumferential direction, and the annular recess 20 itself can be configured to be freely expandable in diameter. Therefore, the effects described below are also achieved.

[0068] The size of the outer diameter (inner diameter) of the generally produced paper container 2 is determined, but there is a tolerance, resulting in a size difference of about 0.5 mm to 1 mm. Even for a paper container 2 with a smaller inner diameter, the annular recess 20 configured to be freely expandable in diameter is expanded, so that the paper lid 1 can be easily fitted. That is, by previously introducing the wrinkles 27, even when fitting to a paper container 2 with a smaller inner diameter, new unnecessary wrinkles can be prevented from being generated, and leakage of the content along the unnecessary wrinkles can be prevented.

[0069] In addition, the present invention is not limited to the above-described embodiments. For example, asFigure 10 As shown in (a) of , a bent portion 31 that bends outward may be formed in the outer fitting portion 16. Figure 10 (b) of is an enlarged view of the region surrounded by a dashed line in (a) of . The bent portion 31 can be formed into a bent shape by bending the outer surface and the inner surface of the outer fitting portion 16 outward about point P1, then folding back the bent outer surface and inner surface about point P2, and further bending the folded-back outer surface and inner surface at point P3. Figure 10 As shown in (a) of , the wrinkling 27 formed in the outer fitting portion 16 tends to recover. In contrast, by forming the bent portion 31 in a crossing manner with respect to the wrinkling 27, as shown in (b) of , it is possible to suppress the tendency of the wrinkling 27 compressed in the circumferential direction to recover using the bent portion 31. The wrinkling 27 continues to at least reach the inner fitting portion 14, the top portion 15, and the outer fitting portion 16 that form the annular recess 20. Therefore, it is possible to suppress, via the bent portion 31 formed in the outer fitting portion 16, the tendency of the wrinkling 27 that crosses it to recover to the opposite side of the compression direction until reaching the continuous inner fitting portion 14.

[0070] Such a bent portion 31 is formed to cross the wrinkling 27 formed in the outer fitting portion 16. In particular, Figure 11 As shown in (a) of , the wrinkling 27 compressed in the circumferential direction wants to recover. In contrast, by forming the bent portion 31 in a crossing manner with respect to the wrinkling 27, as shown in (b) of , it is possible to suppress the tendency of the wrinkling 27 compressed in the circumferential direction to recover using the bent portion 31. The wrinkling 27 continues to at least reach the inner fitting portion 14, the top portion 15, and the outer fitting portion 16 that form the annular recess 20. Therefore, it is possible to suppress, via the bent portion 31 formed in the outer fitting portion 16, the tendency of the wrinkling 27 that crosses it to recover to the opposite side of the compression direction until reaching the continuous inner fitting portion 14. Figure 11 As shown in (b) of , it is possible to suppress the tendency of the wrinkling 27 compressed in the circumferential direction to recover using the bent portion 31. The wrinkling 27 continues to at least reach the inner fitting portion 14, the top portion 15, and the outer fitting portion 16 that form the annular recess 20. Therefore, it is possible to suppress, via the bent portion 31 formed in the outer fitting portion 16, the tendency of the wrinkling 27 that crosses it to recover to the opposite side of the compression direction until reaching the continuous inner fitting portion 14.

[0071] Therefore, it is possible to suppress, via the bent portion 31, the tendency of the wrinkling 27 in the inner fitting portion 14 to recover in the circumferential direction. As a result, it is possible to maintain the state in which the wrinkling 27 in the inner fitting portion 14 is compressed in the circumferential direction. As a result, it is possible to prevent the contents of the paper container 2 from leaking along the wrinkling 27 of the inner fitting portion 14.

[0072] In addition, the bent portion 31 has an advantageous effect in that even when the wrinkling 27 is not compressed toward the inner side in the circumferential direction, it is possible to suppress the force of the wrinkling 27 itself to open via the bent portion 31.

[0073] In addition, when the bent portion 31 is provided, the structures of the covering portion 12 and the extended portion 13 around the top plate portion 11 may be omitted. In this case, the structure is such that the outer periphery of the top plate portion 11 is directly connected to the lower end of the lower side portion 14a of the inner fitting portion 14.

[0074] For example, as shown in , the position of the bent portion 31 is preferably formed at a position where it can contact the lower side of the curled portion 28 at the upper end of the paper container 2 when the paper container 2 is fitted into the annular recess 20. That is, by bending the bent portion 31 outward, the inner surface 31a bent about P1 sometimes bulges inward. Through this bulging inner surface 31a, it is possible to engage with the curled portion 28 of the paper container 2 and fit the paper lid 1 in a stable state. Figure 12 As shown in , the position of the bent portion 31 is preferably formed at a position where it can contact the lower side of the curled portion 28 at the upper end of the paper container 2 when the paper container 2 is fitted into the annular recess 20. That is, by bending the bent portion 31 outward, the inner surface 31a bent about P1 sometimes bulges inward. Through this bulging inner surface 31a, it is possible to engage with the curled portion 28 of the paper container 2 and fit the paper lid 1 in a stable state.

[0075] In addition, in order to fit the paper lid 1 in a stable state, as shown in (a) of Figure 13 , a bent portion 32 that bends inward may be formed in the outer fitting portion 16. The detailed structure of the bent portion 32 is the same as that of the bent portion 31, so the description thereof will be omitted below. For example, as shown in (a) of Figure 13 , the bent portion 32 is formed at a position where it can contact the lower side of the curled portion 28 of the paper container 2 when the paper container 2 is fitted into the annular concave portion 20. Thus, the bent portion 32 can be engaged with the curled portion 28 of the paper container 2, and the paper lid 1 can be fitted in a stable state. Figure 13 (b) of Figure 13 is a view showing another embodiment of the bent portion 32 that bends inward. In this embodiment, an example is shown in which the bent portion 32 having a triangular cross-sectional shape in (a) of

[0076] is processed into a flattened shape. The curled portion 28 of the paper container 2 can be more stably engaged via the flattened bent portion 31. In addition, in this method, the structure of the curled portion 17 may be omitted, and the inner fitting portion 14 is erected in the vertical direction, but it is not limited thereto.

[0077] (Manufacturing method of the paper lid 1)

[0078] <Example of a processing machine>

[0079] Figure 14 is a schematic cross-sectional view showing an example of a processing machine that can be used for manufacturing a paper lid according to an embodiment of the present invention.

[0080] The processing machine 100 is, for example, a stamping machine. For example, by using the processing machine 100 shown in Figure 14 , the paper lid 1 having the annular concave portion 20 can be manufactured from the blank 10.

[0081] 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. In addition, in the processing machine 100, a mounting table 170 is further provided outside the drawing die 110 and the blank holder 120. In addition, Figure 14 shows the cross-sectional shape of the processing machine 100, and such a cross-sectional shape is formed in the circumferential direction.

[0082] Actually, regarding manufacturing the paper lid 1 by the processing machine 100, first, the blank 10 is placed on the placement surface 142 of the plunger 140, the placement surface 112 of the drawing die 110, and the mounting table 170.

[0083] Next, as shown in Figure 15As shown in (a) of , the blank holder 120, the drawing punch 130, and the first side holder 160 are moved in the downward direction ZD, and the blank 10 is pressed between the drawing die 110, the plunger 140, and the second side holder 150. Then, in the state where the blank is being pressed, 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 in the downward direction ZD. As a result, in the space surrounded by the mounting table 170, 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 that sandwich the blank 10 are lowered in the downward direction ZD. As a result, the blank 10 is blanked between the mounting table 170 and the blank holder 120, and the blank 10 can be formed into a substantially circular shape in plan view.

[0084] The drawing die 110 has a guide hole 111 and a mounting surface 112. The guide hole 111 is, for example, a circular hole. The mounting surface 112 is provided outside the guide hole 111. The mounting surface 112 faces the blank holder 120. The mounting surface 112 is a surface on which the blank 10 can be mounted. In addition, a caulking portion 115 in the shape of a circular groove is provided at the intersection of the mounting surface 112 and the guide hole 111 of the drawing die 110.

[0085] 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 mounting surface 112. The blank holder 120 presses the blank 10 placed on the mounting surface 112. In addition, a caulking portion 125 in the shape of a circular groove is provided at the intersection of the guide hole 121 and the pressing surface 122 in the blank holder 120.

[0086] The drawing punch 130 can move in the upward direction ZU and the downward direction ZD in the guide hole 121. The upward direction ZU and the downward direction ZD intersect the mounting surface 112, for example, perpendicularly. The downward direction ZD is the direction opposite to the upward direction ZU. A punch surface 132 is formed at the front end portion of the drawing punch 130. The punch surface 132 is formed of a flat surface and presses the blank 10. In addition, the drawing punch 130 is formed with a first side peripheral surface 131a on the upward direction ZU side and a second side peripheral surface 131b on the downward direction ZD side.

[0087] The plunger 140 can move in the upward direction ZU and the downward direction ZD in the guide hole 111. A mounting surface 142 is provided at the front end portion of the plunger 140. The mounting surface 142 faces the punch surface 132. The diameter D1 of the mounting surface 142 is equal to or less than the diameter D2 of the punch surface 132 of the drawing punch 130. In addition, a side peripheral surface 141 is formed on the plunger 140.

[0088] The second side cage 150 is capable of moving in the respective directions of the ascending direction ZU and the descending direction ZD within the guide hole 111 while bringing its side peripheral surface 151 into circumferential contact with the guide hole 111. The second side cage 150 is formed with an annular protrusion 152 at its upper end, and a stepped portion 153 having a step is provided on the outside of the annular protrusion 152 and is arranged downward from the front end of the annular protrusion 152.

[0089] The first side cage 160 is capable of moving in the respective directions of the ascending direction ZU and the descending direction ZD within the guide hole 121 while bringing its side peripheral surface 161 into circumferential contact with the guide hole 121. The first side cage 160 is formed with an annular protrusion 162 at its lower end, and a stepped portion 163 having a step is provided on the outside of the annular protrusion 162 and is arranged upward from the front end of the annular protrusion 162.

[0090] In addition, the movements of the above-described drawing die 110, blank holder 120, drawing punch 130, plunger 140, second side cage 150, and first side cage 160 in the ascending direction ZU and the descending direction ZD are all performed by a cylinder (not shown), but are not limited thereto, and of course, other known drive mechanisms can also be used.

[0091] Next, as Figure 15 shown in (b) of, only the drawing punch 130 and the plunger 140 are pressed downward in the descending direction ZD. During this period, the peripheral region of the blank 10 is pressed by being clamped between the drawing die 110 and the blank holder 120. As a result, the blank 10 extends in the descending direction ZD, and as a result of pressing the central region of the blank 10, an external shape corresponding to the top plate portion 11 and the covering portion 12 is formed.

[0092] Next, as Figure 16 shown in (a) of, the drawing die 110, the blank holder 120, and the first side cage 160 are pressed downward in the descending direction ZD. As a result, the annular protrusion 162 of the first side cage 160 approaches the stepped portion 153 of the second side cage 150 in a manner of being fitted therewith, and the annular protrusion 152 of the second side cage 150 approaches the stepped portion 163 of the first side cage 160 in a manner of being fitted therewith. As a result, the blank 10 is deformed according to the approaching shapes of the annular protrusion 162 and the stepped portion 153 and the annular protrusion 152 and the stepped portion 163, and as a result, an external shape corresponding to the above-described extended portion 13 and the inner fitting portion 14 is formed. That is, in this process, according to the amount corresponding to the annular protrusion 152 in the second side cage 150, the annular protrusion 162 of the first side cage 160 is pressed into the region outside the outer periphery away from the covering portion 12, thereby forming a shape exactly corresponding to the extended portion 13.

[0093] Next, as shown in (b) of Figure 16 , only the drawing die 110 and the blank holder 120 are raised in the upward direction ZU. As a result, the end portion of the blank 10 is formed in the upward direction ZU while being clamped 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, an external shape corresponding to the top portion 15 and the outer fitting portion 16 is formed. That is, in this process, according to the amount corresponding to the stepped portion 153 in the second side holder 150, the drawing die 110 presses in from a region outside the outer periphery away from the inner fitting portion 14, thereby forming a shape exactly corresponding to the top portion 15.

[0094] Next, as shown in (a) of Figure 17 , only the drawing die 110 and the blank holder 120 are lowered in the downward direction ZD. Alternatively, the plunger 140, the first side holder 160, the second side holder 150, and the drawing punch 130 are raised in the upward direction ZU. As a result, the end portion of the blank 10 formed in the upward direction ZU just enters the circular groove-shaped curling portions 115 and 125. Moreover, as the drawing die 110 and the blank holder 120 are gradually lowered, the end portion of the blank 10 deforms along the circular groove shape of the curling portions 115 and 125, and as a result, the curled portion 17 is formed. Thus, the paper lid 1 applying the present invention can be manufactured from the blank 10.

[0095] Next, as shown in (b) of Figure 17 , the drawing punch 130 is moved in the upward direction ZU to separate it from the blank 10. Next, the drawing die 110 and the second side holder 150 are lowered in the downward direction ZD to take out the completed paper lid 1.

[0096] According to the manufacturing method of the paper lid 1 manufactured through the above process, it is possible to realize the formation of a so-called dome shape bulging upward formed by the top plate portion 11 and the covering portion 12 which are the characteristic portions of the paper lid 1. That is, by forming a shape corresponding to the top plate portion 11 and the covering portion 12 by only lowering the drawing punch 130 and the plunger 140 as shown in (b) of Figure 15 , and then forming the shape of the extension portion 13 and the inner fitting portion 14 as shown in (a) of Figure 16 , it can be realized. After such a process, as shown in (a) of Figure 17 , by pressing down the drawing die 110 and the blank holder 120 or by raising the plunger 140, the first side holder 160, the second side holder 150, and the drawing punch 130 in the upward direction ZU, the curled portion 17 can be formed by means of the circular groove-shaped curling portions 115 and 125, and these characteristic shapes can be realized by the processing machine 100 in one cycle.

[0097] In addition, in the present invention, in the process of forming the inner fitting portion 14 shown in (a) of Figure 16 , as shown in Figure 18 , a tapered surface 162a is provided at the root portion of the annular protrusion 162 of the first cage 160, and a tapered surface 152a is provided at a portion near the upper end of the annular protrusion 152 of the second cage 150. The tapered surface 162a is formed by inclining only the root portion from the annular protrusion 162 to the stepped portion 163. The tapered surface 152a is formed by inclining only the portion near the upper end of the annular protrusion 152. By bringing the second cage 150 closer to the first cage 160, these tapered surfaces 152a and 162a face each other, and the blank 10 held between them is deformed along the inclinations of the tapered surface 152a and the tapered surface 162a. As a result, as shown in Figure 3 , in the inner fitting portion 14, a shape can be formed in which the lower portion 14a expands in diameter toward the outside, and the upper portion 14b above the lower portion 14a extends upward with substantially the same diameter.

[0098] In a state where such tapered surfaces 162a and 152a are actually formed, by pressing the first cage 160 in the downward direction ZD, the vector direction of the load can be decomposed from the downward direction ZD into a load vector toward the thickness direction of the blank 10 as shown by the arrow in Figure 18 . As a result, the wrinkles 27 in the blank 10 generated in the above-mentioned drawing process are compressed and also compressed toward the inner circumferential side. As a result, by increasing the compression force on the wrinkles 27 based on the load vector toward the thickness direction of the blank 10, the maximum void area can be further reduced as in Example 4 of the present invention shown in Figure 9 , and leakage of the content can be reliably suppressed.

[0099] Figure 19An example is shown in which the paper thickness of the paper lid 1 actually formed by the above-described deep drawing method is measured. The paper thickness of the original blank 10 is 0.32 mm. In contrast, the paper thickness becomes thicker from the top plate portion 11 toward the covering portion 12 and the extending portion 13. This is due to the influence brought about by the proximity of the wrinkles 27 generated by deep drawing, and the paper thickness becomes thicker based on the wrinkles 27. On the other hand, in the lower side portion 14a of the inner fitting portion 14 in particular, the paper thickness becomes thinner. During the deep drawing process in which the first side cage 160 is pressed downward in the ZD direction, a compressive force is applied to the lower side portion 14a of the inner fitting portion 14, and as a result, the paper thickness itself becomes thinner. At this time, with the conical surfaces 162a and 152a formed as described above, the first side cage 160 is pressed downward in the ZD direction, thereby further applying a load vector in the thickness direction of the blank 10. As a result, the paper thickness of the lower side portion 14a becomes thinner, and the paper thickness itself can be made substantially uniform. Furthermore, by thinning the paper thickness by using compressive force in the lower side portion 14a of the inner fitting portion 14, the lower side portion 14a itself can be made harder. As a result, it is easier to apply a pressing force to the inner peripheral surface 21 of the container portion of the paper container 2 from the lower side portion 14a of the inner fitting portion 14, and leakage of the liquid content in the paper container 2 can be effectively suppressed. The paper thickness of the upper side portion 14b and the top portion 15 different from the lower side portion 14a is thicker than that of the lower side portion 14a. However, by applying a greater load to the lower side portion 14a with a thinner paper thickness during deep drawing and not applying a load to other portions with a thicker paper thickness, breakage of this portion can be prevented.

[0100] In addition, as a result of applying a compressive force in the thickness direction of the paper to the lower side portion 14a of the inner fitting portion 14 in particular, a compressive force in the 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 are the shallowest, and the depth of the wrinkles in the upper side portion 14b, the top portion 15, and the outer fitting portion 16 of the inner fitting portion 14 becomes deeper. By making the wrinkles 27 shallower in the lower side portion 14a of the inner fitting portion 14, leakage of the liquid content in the paper container 2 can be effectively suppressed as well. In addition, whether it is the lower side portion 14a or the upper side portion 14b, as long as the depth of the wrinkles 27 in at least the inner fitting portion 14 is shallower than the depth of the wrinkles 27 in the other top portion 15 and outer fitting portion 16, the same effect can be exhibited.

[0101] In addition, in the case where a bent portion 31 that bends outward is formed in the outer fitting portion 16, in Figure 17 the process of forming the curled portion 17 shown in (a) of Figure 20 a deep drawing die 110' having the shape shown in (a) of Figure 20 is used. In this deep drawing die 110', the region surrounded by the dashed line in (a) of Figure 20(b). The drawing die 110’ is formed with an abutting surface 115a at the curling portion 115 that can abut against the end portion 10a of the blank 10. In a state where the end portion 10a of the blank 10 abuts against the abutting surface 115a of the curling portion 115, only the drawing die 110 and the blank holder 120 are lowered in the downward direction ZD. As a result, the portion of the blank 10 corresponding to the outer fitting portion 16 is compressed in the vertical direction, and as a result, it naturally bends outward to form the above-mentioned bent portion 31. At this time, by forming a circular groove in the curling portion 115, the portion of the blank 10 corresponding to the outer fitting portion 16 is compressed in the vertical direction, and as a result, it can naturally bend outward.

[0102] In addition, as Figure 21 shown, by further expanding the flat abutting surface 115a of the curling portion 115, the end portion 10a of the blank 10 can be easily caught via the abutting surface 115a. In this case, it is also preferable to slightly form a groove in the curling portion 115 so that the portion of the blank 10 corresponding to the outer fitting portion 16 can bend outward.

[0103] In addition, when a bent portion 32 that bends inward is formed in the outer fitting portion 16, in the process of forming the curled portion 17 shown in Figure 17 (a), the first side holder 160’ having the shape shown by Figure 22 is used. In the first side holder 160’, a concave portion 165 that is processed into a concave shape toward the inside is formed at a position on the side peripheral surface 161 that faces the drawing die 110. By forming such a concave portion 165, when only the drawing die 110 and the blank holder 120 are lowered in the downward direction ZD, the end portion 10a of the blank 10 is pressed via the curling portion 125 of the blank holder 120. As a result, the portion of the blank 10 corresponding to the outer fitting portion 16 is compressed in the vertical direction and retreats into the concave portion 165 where the sole pressing does not work. As a result, a bent portion 32 that bends inward can be formed in the concave portion 165.

[0104] Reference Signs Explanation

[0105] 1: Paper lid; 2: Paper container; 10: Blank; 10a: End; 11: Top plate part; 11a: Top surface; 11b: Container surface; 12: Wrapping part; 13: Extension part; 14: Inner fitting part; 14a: Lower part; 14b: Upper part; 15: Top; 16: Outer fitting part; 17, 28: Crimping part; 20: Annular recess; 21: Inner peripheral surface of container part; 27: Fold; 31, 32: Bending part; 100: Processing machine; 110: Drawing die; 111, 121: Guide hole; 112: Placing surface; 115: Hemming part; 115a: Contact surface; 120: Blank holder; 122: Pressing surface; 125: Hemming part; 130: Drawing punch; 132: Punch surface; 140: Plunger; 141, 151, 161: Side peripheral surface; 142: Placing surface; 150, 160: Side holder; 152, 162: Annular protrusion; 153, 163: Step part; 165: Recess; 170: Placing table; OEP: Peripheral part.

Claims

1. A paper lid which is a paper-made lid fitted to a paper container, characterized in that: The paper lid has: A top plate portion; A covering portion which is provided along the outer periphery of the top plate portion and extends downward, and the covering portion is continuous with the top plate portion; An outer extension portion which is provided along the outer periphery of the covering portion and extends outward, and the outer extension portion is continuous with the covering portion; An inner fitting portion which is provided along the outer periphery of the outer extension portion and extends upward, and the inner fitting portion is continuous with the outer extension portion; A top portion which is provided along the outer periphery of the inner fitting portion and extends outward, and the top portion is continuous with the inner fitting portion; and An outer fitting portion which is provided along the outer periphery of the top portion and extends downward, and the outer fitting portion is continuous with the top portion, A lower portion of the inner fitting portion that is continuous with the outer extension portion is formed with wrinkles extending in the vertical direction over the entire circumference on its inner surface, and when fitted to the paper container, this lower portion can contact the inner peripheral surface of the container portion of the paper container.

2. The paper lid according to claim 1, characterized in that: The wrinkles are compressed toward the circumferential inner side.

3. The paper lid according to claim 2, characterized in that: The void area of the cross-section of the fold is 4359 μm 2 or less.

4. The paper lid according to claim 1, characterized in that: The height of the inner fitting portion exceeds 6 mm.

5. The paper lid according to claim 1, characterized in that: The lower portion of the inner fitting portion expands in diameter toward the outside, and the upper portion of the inner fitting portion above the lower portion extends upward with substantially the same diameter.

6. The paper lid according to claim 1, characterized in that: When fitted to the paper container, this lower portion of the inner fitting portion can press the inner peripheral surface of the container portion of the paper container based on the force of the continuous outer extension portion wanting to expand in diameter.

7. The paper lid according to claim 1, characterized in that: The paper thickness of the lower portion of the inner fitting portion is thinner than the paper thickness of the upper portion of the inner fitting portion and the outer extension portion.

8. The paper lid according to claim 1, characterized in that: The wrinkles of the inner fitting portion are shallower than the wrinkles of the top portion and the outer fitting portion.

9. A paper lid which is a paper-made lid fitted to a paper container, characterized in that: The paper lid has: A top plate portion; An inner fitting portion which is provided at a position on the outer peripheral side of the top plate portion and extends upward; A top portion which is provided along the outer periphery of the inner fitting portion and extends outward, and the top portion is continuous with the inner fitting portion; And An outer fitting portion which is provided along the outer periphery of the top portion and extends downward, and the outer fitting portion is continuous with the top portion, At least continuous wrinkles are formed over the entire circumference on at least the inner surface from the inner fitting portion via the top portion to the outer fitting portion, The outer fitting portion is formed with a bent portion that bends outward.

10. A paper lid which is a paper-made lid fitted to a paper container, characterized in that: The paper lid has: A top plate portion; An inner fitting portion which is provided at a position on the outer peripheral side of the top plate portion and extends upward; A top portion which is provided along the outer periphery of the inner fitting portion and extends outward, and the top portion is continuous with the inner fitting portion; And An outer fitting portion is provided along the outer periphery of the top portion and extends downward, and the outer fitting portion is continuous with the top portion. At least continuous wrinkles are formed over the entire circumference on at least the inner surface from the inner fitting portion through the top portion to the outer fitting portion. The outer fitting portion is formed with a bent portion that bends inward.

11. The paper lid according to claim 9 or 10, wherein The wrinkles are compressed toward the circumferential inner side.

12. The paper lid according to claim 11, wherein The cross-sectional void area of the fold is 4359 μm 2 or less.

13. The paper lid according to claim 9, wherein The paper lid further has: A covering portion is provided along the outer periphery of the top plate portion and extends downward, and the covering portion is continuous with the top plate portion; and An extended portion is provided along the outer periphery of the covering portion and extends outward, and the extended portion is continuous with the covering portion. The inner fitting portion is continuous with the extended portion, and when fitted to the paper container, the lower side portion of the inner fitting portion that is continuous with the extended portion can contact the inner peripheral surface of the container portion of the paper container.

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