Can lid and can container

Abstract

A can lid (1) comprises: a disk-shaped panel part (21); a flange part (23) that is seamed to a can body (101); and an annular groove part (22) that is provided between the panel part (21) and the flange part (23) and protrudes downward. An annular panel outer peripheral part (33) that is continuous with the groove part (22) and is inclined radially inward and downward from the flange-part (23) side toward the center side of the can lid (1) is formed on the outer-peripheral-edge side of the panel part (21).

Description

Can Lid and Can Container

[0001] The present invention relates to a can lid and a can container.

[0002] Conventionally, as a can lid used for can containers, there is known a technology that includes a panel portion and a tab, and breaks a score line formed on the panel portion by operating the tab. Further, for example, Japanese Patent Laid-Open No. 2021-187470 and Japanese Patent No. 4731188 also disclose a full-open type can lid (FOE) in which an annular score line is formed along the entire circumference of the peripheral portion of the panel portion, and an opening is provided across the entire panel portion.

[0003] Japanese Patent Laid-Open No. 2021-187470, Japanese Patent No. 4731188

[0004] When such a can lid is used for a positive-pressure can for carbonated beverages such as beer, for example, the center of the can lid swells into a dome shape. At this time, the opening tab attached to the rivet portion lifts up from the panel portion, and is displaced such that its finger hook portion is lifted upward. This may cause a so-called bulge defect, in which the finger hook portion of the tab protrudes beyond the seam between the can lid and the can body. If the finger hook portion of the tab protrudes beyond the seam between the can lid and the can body, there is a risk that the tab may catch on other members during transportation or the like, causing a malfunction. In particular, in the case of a full-open type can lid, since the rivet portion is arranged on the outer peripheral side relative to the center of the panel portion of the can lid, there is a risk of bulge defect.

[0005] For this reason, when used for carbonated beverages such as RTD (Ready To Drink) which have a higher internal pressure than carbonated beverages such as beer, there is a risk that the bulge pressure performance of the can lid may decrease, and there is a demand for a can lid applicable to such cases.

[0006] Accordingly, an object of the present invention is to provide a can lid and a can container that can suppress lifting of the tab from the panel portion and suppress bulge defect.

[0007] According to one aspect of the present invention, the can lid comprises a disc-shaped panel portion, a flange portion that crimps the can body, and an annular groove portion provided between the panel portion and the flange portion and projecting downward, wherein an annular panel outer periphery portion continuous with the groove portion is formed on the outer peripheral edge side of the panel portion, and the panel outer periphery portion is inclined radially inward and downward toward the center of the can lid from the groove portion.

[0008] According to the present invention, it is possible to provide a can lid and a can container that can suppress bulge defects.

[0009] Figure 1 is a cross-sectional view showing the configuration of a can container according to one embodiment of the present invention. Figure 2 is a plan view showing the configuration of a can lid used in the same can container. Figure 3 is a cross-sectional view showing the configuration of the can lid. Figure 4 is a cross-sectional view showing the main components of the can lid. Figure 5 is a cross-sectional view showing the configuration of a can lid of a can container according to another embodiment of the present invention. Figure 6 is a cross-sectional view showing the configuration of a can lid of a can container according to another embodiment of the present invention. Figure 7 is a cross-sectional view showing the configuration of a can lid of a can container according to another embodiment of the present invention.

[0010] Hereinafter, the configuration of a can container 100 and a can lid 1 used for the can container 100 according to one embodiment of the present invention will be described with reference to Figures 1 to 4. Figure 1 is a cross-sectional view showing the configuration of a can container 100 according to one embodiment of the present invention. Figure 2 is a plan view showing the configuration of a can lid 1 used for the can container 100. Figure 3 is a cross-sectional view showing the configuration of the can lid 1, and Figure 4 is an enlarged cross-sectional view showing the configuration of the protective part of the panel portion 21 of the can lid 1.

[0011] As shown in Figures 1 to 4, the can container 100 is a so-called full-open type (FOE) container in which the panel portion 21 of the can lid 1 opens over substantially the entire surface. The can container 100 is a positive-pressure can in which the internal pressure is positive. The can container 100 is filled with a carbonated beverage as its contents 200. Here, the carbonated beverage is a carbonated beverage. Examples of carbonated beverages include beer, low-malt beer, beer-like alcoholic beverages, beer-like non-alcoholic beverages, highballs, shochu cocktails, sours and other low-alcohol beverages, and non-alcoholic carbonated beverages. However, carbonated beverages are not limited to these. In addition, the can container 100 may be filled with something other than a carbonated beverage as its contents 200.

[0012] The can container 100 comprises a can lid 1 and a can body 101. The can container 100 is formed by filling it with a beverage and then integrally crimping and fixing the can lid 1 and the can body 101 together by a crimping process, for example, by double crimping. The can container 100 is formed by airtightly fixing the can lid 1 and the can body 101 together with a crimping portion 100a. The can container 100 is a so-called two-piece can in which the body portion 111 and the bottom portion 112 of the can body 101 are integrated.

[0013] As shown in Figures 1 to 3, the can lid 1 comprises a can lid body 11 and a tab 12. The can lid 1 is formed such that the score 31 formed on the can lid body 11 can be broken by operating the tab 12.

[0014] As a specific example, as shown in Figure 2, the can lid 1 is a fully open-end (FOE) lid, with the opening covering the entire surface of the panel portion 21. The can lid 1 is manufactured by press-forming a metal sheet to form the can lid body 11 and the tab 12 in separate processes, after which the tab 12 is fixed to the panel portion 21. The metal sheet used to form the can lid body 11 can be an aluminum alloy sheet with a resin coating on its surface or a surface-treated steel sheet. The metal sheet used to form the tab 12 can be an aluminum alloy sheet, for example.

[0015] As shown in Figures 1 to 3, the can lid body 11 comprises a panel portion 21, an annular groove portion 22 provided continuously on the outer peripheral edge of the panel portion 21, and a first flange portion 23 provided on the outer peripheral edge of the annular groove portion 22.

[0016] As shown in Figure 2, the panel portion 21 is configured in a disc shape. The panel portion 21 includes a score 31, a rivet portion 32, a panel outer periphery portion 33, a protective portion 34, a finger insertion recess 35, and an auxiliary score 36. The panel portion 21 may also have a display portion such as braille to indicate the contents of the can container 100. The panel portion 21 may also have protrusions and recesses for product identification, design, reinforcement, etc.

[0017] As shown in Figure 3, the score 31 is an opening score that forms an opening in the panel portion 21, formed by a score line that breaks when the tab 12 is opened. By breaking, the score 31 forms an opening in the panel portion 21 of the can lid 1. In other words, the score 31 surrounds the area that forms the opening of the can lid 1, that is, the area that becomes the opening piece of the panel portion 21 that detaches from the part of the panel portion 21 that is integrally fixed to the can container 100 by the crimping portion 100a after being broken by the score 31. Since the can lid 1 is a fully open type, the score 31 is formed by a circular or substantially circular score line, for example, as shown in Figure 2. By breaking, the score 31 makes it possible to remove the portion of the panel portion 21 radially inward of the score 31 as an opening piece, together with the rivet portion 32, from the portion of the panel portion 21 radially outward of the score 31.

[0018] The score lines forming the score 31 are grooves that constitute a weak point, causing a portion of the panel portion 21 to break in the shape of an opening due to external force. The score lines forming the score 31 are, for example, wedge-shaped grooves provided on the outer surface of the panel portion 21, and the score 31 causes a portion of the panel portion 21 to be made thin. Here, the outer surface of the panel portion 21 refers to the main surface exposed to the outside when the can lid 1 is attached to the can body 101 of the can container 100, that is, the surface that constitutes the upper surface of the can container 100.

[0019] The score 31 is formed, for example, on a protective portion 34 provided on the outer peripheral edge of the panel portion 21. Specifically, the score 31 is formed on the upper surface of the third layer 63 of the protective portion 34, which will be described later. The score 31 is not limited to a circular shape, and for example, it may be formed in a partially intermittent arc shape, opening up most of the panel portion 21, with the opened pieces being partially continuous with the panel portion 21.

[0020] As shown in Figures 1 to 3, the rivet portion 32 is provided on one main surface of the panel portion 21, specifically on the outer surface of the panel portion 21. The rivet portion 32 is located on the outer peripheral edge of the panel portion 21 and is located on the central side of the score 31. The rivet portion 32 is located radially inward of the score 31 and adjacent to the score 31.

[0021] The rivet portion 32 protrudes from one main surface of the panel portion 21 in a hollow cylindrical shape. The rivet portion 32 is formed by performing a rivet-down process by coining on a part of the panel portion 21. The tab 12 is fixed to the panel portion 21 by crimping the rivet portion 32 after the tab 12 is placed. In Figures 1 to 3, the rivet portion 32 is shown in its state after crimping.

[0022] The outer periphery of the panel 33 is formed in an annular shape on the first flange portion 23 side (groove portion 22 side) of the panel portion 21. For example, the outer periphery of the panel 33 is formed continuously and integrally with the groove portion 22. The outer periphery of the panel 33 is inclined radially inward and downward from the first flange portion 23 side (groove portion 22 side) toward the center of the can lid 1 (panel portion 21). The outer periphery of the panel 33 is provided, for example, between the groove portion 22 and the protective portion 34. For example, the inclination angle of the outer periphery of the panel 33 with respect to the direction perpendicular to the axial direction of the can lid 1 is in the range of 3° to 30°. Figure 4 shows a reference line along the direction perpendicular to the axial direction of the can lid 1, indicated by a dashed line. The area of ​​the panel portion 21 inside the outer periphery of the panel 33 and the protective portion 34 extends planarly in the direction perpendicular to the axial direction of the can lid 1, and the protective portion 34, finger insertion recess 35, auxiliary score 36, protrusions and recesses are partially provided therein. Here, the area inside the outer peripheral portion 33 and protective portion 34 of the panel portion 21 is the region that becomes the open piece of the panel portion 21 when the score 31 breaks.

[0023] As shown in Figures 3 and 4, the protective portion 34 is formed by folding the panel portion 21 in an annular shape. That is, the protective portion 34 is a multilayered portion in which the panel portion 21 is partially multilayered. The protective portion 34 is formed by folding the panel portion 21 radially inward from the outer peripheral edge and radially outward from the rivet portion 32 four times. The protective portion 34 is provided, for example, continuously with the outer peripheral portion 33 of the panel portion 21. A score 31 is formed on a part of the protective portion 34, protecting the fingers from injury by the inner peripheral edge of the opening of the broken panel portion 21 and the outer peripheral portion of the part of the panel portion 21 that is the opening piece when the panel portion 21 breaks along the score 31.

[0024] The protective portion 34 is formed by folding the panel portion 21 four times, thereby partially creating a five-layer structure. As a specific example, the protective portion 34 has a first layer 61, a second layer 62, a third layer 63, a fourth layer 64, and a fifth layer 65, and includes a first folded portion 71 folded between the first layer 61 and the second layer 62, a second folded portion 72 folded between the second layer 62 and the third layer 63, a third folded portion 73 folded between the third layer 63 and the fourth layer 64, and a fourth folded portion 74 folded between the fourth layer 64 and the fifth layer 65.

[0025] The first layer 61 is continuous with the outer periphery 33 of the panel. In other words, the first layer 61 is formed from a part of the outer periphery 33 of the panel. Then, the first layer 61, second layer 62, third layer 63, fourth layer 64, and fifth layer 65 are arranged sequentially from the outer periphery 33 toward the can body 101. A score 31 is formed in the third layer 63.

[0026] The protective portion 34 forms an outer protective portion 34a that protects the inner peripheral edge of the portion of the panel portion 21 that is located in the can container 100 when the tab 12 is opened and the score 31 is broken, and an inner protective portion 34b that protects the outer peripheral edge of the portion of the panel portion 21 that is separated from the can container 100 when the score 31 is broken. The outer protective portion 34a is formed, for example, by the first layer 61, the second layer 62 and a part of the third layer 63 (outer from the score 31 of the third layer 63), and the first folded portion 71 is located on the inner peripheral edge of the opened panel portion 21. The inner protective portion 34b is composed of a part of the third layer 63 (inner from the score 31 of the third layer 63), the fourth layer 64 and the fifth layer 65, and the fourth folded portion 74 is located on the outer peripheral edge of the portion of the panel portion 21 that is away from the opening.

[0027] As shown in Figure 4, the first folded portion 71, the second folded portion 72, the third folded portion 73, and the fourth folded portion 74 are formed with a cross-sectional shape that is a curved surface with a predetermined radius of curvature. Specifically, the first folded portion 71, the second folded portion 72, the third folded portion 73, and the fourth folded portion 74 form curved portions in which the radius of curvature on the inner side is curved with a predetermined radius of curvature.

[0028] The inner radius of curvature R1 of the first folded portion 71, the inner radius of curvature R2 of the second folded portion 72, the inner radius of curvature R3 of the third folded portion 73, and the inner radius of curvature R4 of the fourth folded portion 74 are set in the range of 0.1 mm to 0.25 mm, more preferably in the range of 0.125 mm to 0.165 mm.

[0029] For example, the radius of curvature R2 of at least the second folded portion 72, preferably the radius of curvature R1 of the first folded portion 71 and the radius of curvature R2 of the second folded portion 72, is greater than the radius of curvature R3 of the third folded portion 73 and the radius of curvature R4 of the fourth folded portion 74. With these configurations, the outer protective portion 34a has greater strength than the inner protective portion 34b before the score 31 breaks.

[0030] The finger-insertion recess 35 is located below the rear end of the tab 12 where the finger is placed, and is recessed from the outer surface of the panel portion 21.

[0031] As shown in Figure 2, the auxiliary score 36 is formed near the rivet portion 32 of the panel portion 21. The auxiliary score 36 is an impulse score. A portion of the auxiliary score 36 breaks off during the opening operation of the tab 12. The auxiliary score 36 comprises, for example, a main score line 41 and a secondary score line 42 provided on the opposite side of the main score line 41 from the rivet portion 32.

[0032] The main score line 41 is a groove that constitutes a weak point, causing a portion of the panel portion 21 to break in the shape of an opening due to external force. The main score line 41 is, for example, a wedge-shaped groove provided on the outer surface of the panel portion 21. The main score line 41 causes a portion of the panel portion 21 to be made thin. The main score line 41 breaks when the tab 12 is opened, allowing the rivet portion 32 to move upward.

[0033] The secondary score line 42 is provided radially inward of the panel portion 21 compared to the main score line 41. The secondary score line 42 is formed parallel to the main score line 41. The secondary score line 42 is, for example, a groove provided on the outer surface of the panel portion 21. The secondary score line 42 is formed to be shallower than the depth of the main score line 41. That is, the thickness of the portion of the panel portion 21 where the secondary score line 42 is provided is thicker than the thickness of the portion of the panel portion 21 where the main score line 41 is provided. The secondary score line 42 forms a thin wall in a part of the panel portion 21. When the main score line 41 breaks, the secondary score line 42, for example, does not break or its breakage is suppressed.

[0034] The groove 22 is an annular recess provided continuously on the outer edge of the panel 21, which protrudes toward the can body when fixed to the can body. The groove 22 is a so-called countersink. The groove 22 has the function of improving the pressure resistance of the can lid 1.

[0035] The first flange portion 23 is crimped to the open end of the can body 101. The first flange portion 23 has a sealing resin layer on the surface that contacts the can body 101.

[0036] As shown in Figures 2 and 3, the tab 12 comprises a mounting portion 51, a tip portion 52, and a finger rest portion 53. The tab 12 is integrally formed with the mounting portion 51, tip portion 52, and finger rest portion 53. The tab 12 is opened by a finger or the like placed on the finger rest portion 53, causing the tip portion 52 to press against the portion of the score 31 of the panel portion 21 radially inwardly adjacent to the score 31, thereby breaking the score 31.

[0037] The mounting portion 51 is formed in a plate shape and has a rivet hole 51a. The mounting portion 51 is continuous with the tip portion 52 and the finger rest portion 53. The rivet hole 51a is formed with an inner diameter that allows the rivet portion 32 to be inserted. The mounting portion 51 is fixed to the panel portion 21 by the rivet portion 32 when the rivet portion 32 inserted into the rivet hole 51a is crimped.

[0038] The tip portion 52 is formed on the tip side of the tab 12. The tip portion 52 is configured with an arc shape or a polygonal shape. The tip portion 52 is formed, for example, by doubling the outer edge excluding the tip. The tip portion 52 is positioned radially inward and close to the score 31 of the panel portion 21.

[0039] The finger rest portion 53 is the part on which the fingers are placed to lift the tab 12 when opening the tab 12. As shown in Figures 2 and 3, for example, the finger rest portion 53 includes a ring hole 53a and is formed in an annular shape. Specifically, the finger rest portion 53 is configured in the shape of a rectangular frame with arc-shaped corners. The finger rest portion 53 is formed on the opposite side of the tip portion 52, with the mounting portion 51 in between. When the tab 12 is attached to the panel portion 21, the rear end of the finger rest portion 53 faces the finger insertion recess 35. The finger rest portion 53 is formed, for example, by bending the outer peripheral edge and the inner peripheral edge of the ring hole 53a so that they are doubled.

[0040] As shown in Figure 1, the can body 101 is formed in a bottomed cylindrical shape. The can body 101 is formed from, for example, a metal sheet. Examples of metal sheets used to form the can body 101 include aluminum alloy sheets with a resin coating on the surface and surface-treated steel sheets. The can body 101 may also be formed from a resin material.

[0041] The can body 101 comprises a body portion 111, a bottom portion 112, a tapered portion 113, and a second flange portion 114. The body portion 111 is formed in a cylindrical shape. The bottom portion 112 is integrally provided at one end of the body portion 111. One end (lower end) of the tapered portion 113 is integrally continuous with the other end of the body portion 111, and the other end (upper end) is integrally continuous with the second flange portion 114. The tapered portion 113 gradually decreases in diameter from the body portion 111 side toward the second flange portion 114 side. The second flange portion 114 forms the open end of the can body 101. The second flange portion 114 is fixed to the first flange portion 23 by crimping.

[0042] According to the can lid 1 and can container 100 configured as described above, the panel outer peripheral portion 33, which serves as the outer peripheral edge side of the panel portion 21 of the can lid 1, is configured to be inclined downward toward the center of the can lid 1. With this configuration, in the panel portion 21, the portion located radially closer to the center than the panel outer peripheral portion 33 and the protection portion 34 is positioned lower than the panel outer peripheral portion 33. Therefore, the can lid 1 can secure an axial distance from the upper surface on the center side of the panel portion 21 to the upper end of the seamed portion 100a where the can lid 1 and the can body 101 are seamed. Thus, even if the panel portion 21 is deformed into a dome shape by the internal pressure of the can container 100, the can lid 1 can suppress the tab 12 from lifting up from the panel portion 21 until the finger hook portion 53 of the tab 12 protrudes upward beyond the seamed portion 100a.

[0043] Further, when the internal pressure of the can container 100 is positive pressure and the panel portion 21 is deformed into a dome shape by the internal pressure, the panel outer peripheral portion 33 shown in Fig. 3 deforms from the shape facing downward inward along a direction perpendicular to the axial direction, and then deforms to extend in an upwardly inclined direction as shown in Fig. 1. Therefore, when the panel portion 21 deforms due to the internal pressure of the can container 100, a force resisting the internal pressure is generated.

[0044] Therefore, the can lid 1 can suppress deformation of the panel portion 21 against the internal pressure of the can container 100, so it can suppress the finger hook portion 53 of the tab 12 from protruding upward beyond the seamed portion 100a, and can secure pressure resistance.

[0045] As described above, as a countermeasure against bulging, the can lid 1 can suppress lifting of the tab 12 and achieve high pressure resistance. Therefore, even when used in a can container 100 with positive internal pressure, the can lid 1 can suppress defective bulging.

[0046] Furthermore, bulge prevention is possible by setting the inclination angle θ of the outer periphery 33 of the panel to 3° to 30°, but the larger the inclination angle θ, the more advantageous it is for bulge prevention. On the other hand, when the inclination angle θ is large, moldability may decrease. For example, considering both bulge prevention and moldability, the inclination angle θ of the outer periphery 33 of the panel is preferably 6°, and when the inclination angle θ is 6°, the bulge pressure is increased by 0.2 to 0.3 kgf / cm² compared to when the inclination angle θ is 0° (i.e., when the outer periphery 33 of the panel extends in a direction perpendicular to the axial direction of the can lid 1).

[0047] Furthermore, by making each folded portion 71-74 of each layer 61-65 of the protective portion 34 a curved portion with a radius of curvature R, the strength and flexibility of the panel portion 21 are improved. Therefore, when the can container 100 is under positive pressure, each folded portion 71-74 acts as a cushion and expands and contracts. In addition, the curved portions of the third folded portion 73 and the fourth folded portion 74 not only function as the inner protective portion 34b but also improve the strength of the outer edge of the opening piece.

[0048] Therefore, the protection part 34 absorbs the bulge pressure, thereby suppressing the protrusion of the finger hook part 54 from the upper end of the seaming part 100a. In addition, when the score 31 of the panel part 21 is broken by the opening operation of the tab 12, the opening piece of the panel part 21 is difficult to bend, the can lid 1 is easy to open, and poor opening can be prevented. That is, when each of the folded portions 71 to 74 has no curved portion or only a small curved portion, and each of the folded portions 71 to 74 is crushed, the strength of the curved portion is low and the flexibility is poor. Therefore, when the can container 100 is at positive pressure, the can lid 1 has no or low cushioning property, which leads to bulge failure. Besides, there is a risk that the opening piece bends when the can lid 1 is opened, leading to poor opening. However, by setting each of the folded portions 71 to 74 of the present embodiment to a predetermined radius of curvature, cushioning property is generated, and the strength of the outer peripheral side of the opening piece can be improved, so that poor opening of the can lid 1 can be suppressed. Note that, for example, the radii of curvature R1 to R4 of the folded portions 71 to 74 are target values of the radius of curvature on the inner surface side among the inner surface side and the outer surface side of the folded portions 71 to 74 shown by the two-dot chain line in FIG. 4. Therefore, in actual manufacturing, it is preferable to take the radius of curvature such that it forms a circle along the inner surface of the curved portion. That is, it is permissible that the folded portions 71 to 74 of the manufactured can lid 1 are not partially a curved surface with a predetermined radius of curvature, and at least a part of the inner surface side of the curved portion of each folded portion 71 to 74 has or approximates the predetermined radius of curvature.

[0049] In addition, the radius of curvature R1 on the inner surface side of the first folded portion 71, the radius of curvature R2 on the inner surface side of the second folded portion 72, the radius of curvature R3 on the inner surface side of the third folded portion 73, and the radius of curvature R4 on the inner surface side of the fourth folded portion are set to preferably 0.1 mm to 0.25 mm, more preferably 0.125 mm to 0.165 mm. This is because, when each of the radii of curvature R1 to R4 is outside the above numerical range, the fracture surface of the score 31 and the curved portions (the first folded portion 71 and the fourth folded portion 74) of the protection part 34 are separated in the radial direction during opening, which may result in poor safety. In addition, the cushioning property of the folded portions 71 to 74 becomes too good, which may make it difficult to push the score 31 with the tab 12 during opening.

[0050] Furthermore, the radius of curvature R1 of the first folded portion 71 and the radius of curvature R2 of the second folded portion 72 are made larger than the radius of curvature R3 of the third folded portion 73 and the radius of curvature R4 of the fourth folded portion 74. As a result, when the can lid 1 is opened, the curved portions having radii of curvature R1 and R2 (first folded portion 71 and second folded portion 72) act in a widening direction, while the curved portions having radii of curvature R3 and R4 (third folded portion 73 and fourth folded portion 74) act in a narrowing direction. As a result, the outer protective portion 34a has higher strength than the inner protective portion 34b, making it easier to open the can lid 1. For example, by setting the radii of curvature of each folded portion 71 to 74 to the above range and relationship, if the can lid 1 is formed from aluminum 5182 plate material with a thickness of 0.26t, a score pressure resistance strength of 0.63 MPa or more can be ensured.

[0051] As described above, the can lid 1 and can container 100 according to the embodiment make it possible to prevent bulging.

[0052] It should be noted that the present invention is not limited to the embodiments described above. For example, in the above example, a fully open type (FOE) can lid 1 was described in which a protective portion 34 folded in five layers was provided on the panel portion 21, and a groove portion 22 was provided between the panel portion 21 and the first flange portion 23. However, the configuration of the can lid 1 is not limited to this.

[0053] For example, as shown in Figure 5, the protective portion 34 may have three layers instead of five. In this configuration, only one of the outer protective portion 34a or the inner protective portion 34b needs to be formed. For example, in the example in Figure 5, the protective portion 34 is shown with a configuration in which the score 31 is formed on the outer peripheral portion 33 of the panel, allowing for the formation of the inner protective portion 34b.

[0054] Furthermore, as shown in Figure 6, the can lid 1 has a panel outer periphery 33 inside the groove 22, but it may also be configured without a protective portion 34.

[0055] Alternatively, as shown in Figure 7, for example, a can lid with a stay-on tab (SOT) instead of FOE may be used. In this configuration, the can lid 1 does not have a protective portion 34, and for example, the score 31 is formed in part of the panel portion 21, and the rivet portion 32 is located on the central side of the panel portion 21. Even with such a can lid 1, since the outer peripheral portion 33 of the panel is inclined downward radially inward, deformation of the panel portion 21 can be suppressed, and thus the tab 12 can be prevented from protruding upward from the crimping portion 100a.

[0056] In other words, the present invention is not limited to the embodiments described above, and can be modified in various ways during implementation without departing from its essence. Furthermore, each embodiment may be combined as appropriate, and in that case, the combined effects can be obtained. Moreover, the above embodiments include various inventions, and various inventions can be extracted by selecting combinations from the multiple constituent elements disclosed. For example, if the problem can be solved and effects obtained even if some constituent elements are deleted from all the constituent elements shown in the embodiment, then the configuration with these deleted constituent elements can be extracted as an invention.

[0057] 1...Can lid, 11...Can lid body, 12...Tab, 21...Panel section, 22...Groove section, 23...First flange section (flange section), 31...Score, 32...Rivet section, 33...Panel outer perimeter, 34...Protection section, 34a...Outer protection section, 34b...Inner protection section, 35...Finger insertion recess, 36...Auxiliary score, 41...Main score line, 42...Sub-score line, 51...Mounting section, 51a...Rivet hole 52...tip, 53...finger rest, 53a...ring hole, 61...first layer, 62...second layer, 63...third layer, 64...fourth layer, 65...fifth layer, 71...first folded section, 72...second folded section, 73...third folded section, 74...fourth folded section, 100...can container, 100a...sealed section, 101...can body, 111...body section, 112...bottom, 113...tapered section, 114...second flange section.

Claims

1. A can lid comprising: a disc-shaped panel portion; a flange portion that crimps the can body; and an annular groove portion provided between the panel portion and the flange portion and projecting downward, wherein an annular panel outer periphery portion continuous with the groove portion is formed on the outer periphery edge side of the panel portion, and is inclined radially inward and downward from the flange portion side toward the center of the can lid.

2. The can lid according to claim 1, wherein the inclination angle of the outer periphery of the panel is in the range of 3° to 30°.

3. The can lid according to claim 1, wherein the panel portion is provided with a protective portion having an outer protective portion formed by the first, second, and third layers, where the panel portion is folded back toward the can body with the outer periphery of the panel as the first layer, and an inner protective portion formed by the third, fourth, and fifth layers, where the panel portion is folded back toward the can body from the radially inward side of the third layer, continuous with the outer protective portion and the third layer, and curved portions having a radius of curvature are formed in the folded portions between the third and fourth layers and between the fourth and fifth layers.

4. The can lid according to claim 3, wherein a curved portion having a radius of curvature is formed in the folded portion between the first layer and the second layer, and in the folded portion between the second layer and the third layer.

5. The can lid according to claim 4, wherein the radius of curvature R1 on the inner surface of the folded portion between the first layer and the second layer, the radius of curvature R2 on the inner surface of the folded portion between the second layer and the third layer, the radius of curvature R3 on the inner surface of the folded portion between the third layer and the fourth layer, and the radius of curvature R4 on the inner surface of the folded portion between the fourth layer and the fifth layer are each in the range of 0.1 mm to 0.25 mm.

6. The can lid according to claim 5, wherein the radius of curvature R2 is greater than the radii of curvature R3 and the radii of curvature R4.

7. The can lid according to claim 5, wherein the radius of curvature R1 is greater than the radii of curvature R3 and R4.

8. A can container comprising: a can lid according to any one of claims 1 to 7; and a can body to which the can lid is crimped.

9. The can container according to claim 8, wherein the internal pressure is positive.

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