JP2004155449A - Easy-opening can lid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stay-on-tab type easy-opening can lid, on which a tab operation is transmitted effectivelyto a given part of the can lid to make score lines easy to break upon opening the can lid, and the breakage of the score lines by increasing inner pressure is made hard to occur when the can lid is closed. <P>SOLUTION: On the easy-opening can lid 1, a recession 11, having a sloped surface 11b and a bottom surface 11a enclosed with it, is formed on a panel 2 to encircle an area including the tab 6 and an opening strip 10. The grade of the sloped surface 11b to the bottom face 11a of the recession 11 at the outside of the score lines 7 along the sloped surface 11b of the recession 11 and the bottom surface 11a is made smaller in the vicinity to the front end 10a of the opening strip 10, where it is farthest from a rivet 5, than the other part of the sloped surface 11b. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an easy opening can lid which is fastened and fixed to a can body as an end wall on the top plate side of a can container such as a beverage can, and in particular, an opening piece is partially formed in a substantially disk-shaped panel portion. The present invention relates to a partially open type easy opening can lid, wherein the opening piece is pushed down into the can while the opening piece is connected to the panel portion by operating a tab to open the opening.
[0002]
[Prior art]
In a can container for a beverage can, an easy open end which is fastened tightly to the can body as an end wall on the top plate side, an approximately disk-shaped panel portion of the can lid is fully opened. Instead of the full open type, a partial open type easy opening can lid that partially opens using a part of the panel portion of the can lid as a drinking mouth is generally used. Previously, pull-top tab-type can lids were often used as such partial-open type easy-open can lids for beverage cans, in which the tabs and the opening pieces were completely separated from the panel section of the can lid by operating the tab. However, the tabs and opening pieces separated from the cans were inadvertently discarded, causing problems in resource recovery and environmental beautification. Many can lids of a stay-on tub type are used in which an opening piece is pushed down into a can and the tab or the opening piece is opened without being separated from the can.
[0003]
In such an easy opening can lid of a stay tab type, when the panel is bent or deformed when the opening piece is pushed down by the tab, the lever action by the tab is applied to a required portion of the can lid (rivet for fixing the tab). (In the vicinity of the portion) cannot be efficiently transmitted, and as a result, the score line is hardly broken, and the opening property may be deteriorated. In order to cope with such a problem, in an easy opening can lid of a stay-ion tub type, conventionally, generally, an inclined surface and a bottom surface surrounded by the inclined surface are formed with respect to a panel portion of the can lid. By forming the recessed portion so as to include the area of the tab and the opening piece, the tab is prevented from projecting upward from the upper surface of the panel portion of the can lid before opening, and the panel portion is provided with tension. Thus, the panel portion is prevented from being bent or deformed when the opening piece is pressed down by the tab.
[0004]
In addition, with respect to such an easy opening can lid of a stay-tab type, for example, Japanese Patent Application Laid-Open No. 2000-16424 discloses that bending deformation at the tip of a break opening (opening piece) when an internal pressure is applied is suppressed. In order to prevent rupture due to cracks in the score, a step (part between the recess and the counter sink) corresponding to the tip of the break opening (opening piece) is partially cut out and the cut is made. A configuration is described in which a wall portion extending in the radial direction of the can lid is formed in the notched portion.
[0005]
[Problems to be solved by the invention]
By the way, in the easy-open can lid of the stay-ion tub type in which a concave portion including the area of the tab and the opening piece is formed in the panel portion, the inclination angle of the inclined surface with respect to the bottom surface of the concave portion (the inclined surface with respect to the bottom surface of the concave portion) (Bending angle), the greater the tension of the panel part, the more efficiently the leverage of the tab can be transmitted to the required portion of the can lid, and the better the opening property at the time of opening due to breakage of the score line. Can be. On the other hand, in the case of a beverage can containing a beverage containing a gas such as carbon dioxide gas, the internal pressure tends to increase due to vibration, impact, temperature rise, etc., but the can lid has a rivet portion at the top due to the increased internal pressure. When it is inflated into a dome shape, the greater the angle of inclination of the inclined surface with respect to the bottom surface of the concave portion, the greater the degree of bending at that portion and the greater the strength, so that deformation is less likely to occur.
[0006]
In this way, when the bending angle of the inclined surface with respect to the bottom surface of the concave portion is large and the boundary portion between the bottom surface of the concave portion and the inclined surface is difficult to deform, the outward bending stress of the can lid due to the internal pressure is increased accordingly. 5A. As a result, the score line located on the bottom surface of the concave portion acts intensively. As a result, especially near the tip of the opening piece (the portion near the outer periphery of the can lid), as shown in FIG. Since the score line 7 is positioned so as to be substantially perpendicular to the radial direction of the lid, as shown in FIG. 5B, both sides of the groove of the score line 7 engraved in a substantially V-shaped cross section. Since the score line 7 is bent in a mountain fold so as to widen the angle of the wall, thereby easily breaking the score line 7, the other portion of the can lid is squared outward (so-called buckling). Before the score line 7 is broken by internal pressure, There is a possibility that would put out.
[0007]
Regarding this point, as described above, Japanese Patent Application Laid-Open No. 2000-16424 discloses that a step portion (a portion between the concave portion and the counter sink portion) corresponding to the tip of the break opening (opening piece) is partially formed. By forming a notch and forming a wall extending in the radial direction of the can lid in the notch, bending deformation near the tip of the break opening (opening piece) when an internal pressure is applied is suppressed. Although it is described that cracking at the score line (rupture due to bending deformation) is prevented, in such a configuration, bending by the force of the can lid expanding outward by receiving internal pressure is described. Even if the pressure resistance against deformation and bending stress is improved, the notch portion easily becomes the starting point of buckling when an internal pressure exceeding the pressure resistance acts on the can lid (for example, see JP-A-5-112357). The gazette contains the embo It is described that buckling is likely to occur at a portion where a buckling portion is formed, such as buckling or coining.) Therefore, buckling occurs at a notch portion, and a score line near the buckling portion is easily broken. There is a fear that.
[0008]
An object of the present invention is to solve the above-described problems. Specifically, in an easy-open can lid of a stay-ion tub type, at the time of opening, an operation using a tab is efficiently performed on a required portion of the can lid. It is an object of the present invention to make it easy to break the score line by transmitting, and when the internal pressure of the can is increased in an unopened state, the score line is hardly broken due to the internal pressure. .
[0009]
[Means for Solving the Problems]
The present invention solves the above-mentioned problem by providing an opening piece surrounded by a score line on one side of a substantially disk-shaped panel portion so as to leave a hinge portion between both ends of the score line. A tab formed partly in a biased manner to push down the opening piece, such that one end side of the tab is located above the opening piece as a pushing-down end, and the other end side is located away from the opening piece as a gripping part. A concave portion having a sloping surface and a bottom surface surrounded by the sloping surface is formed in the panel portion so as to include the area of the tab and the opening piece while being fixed at a substantially center outside the region of the opening piece by a rivet portion. In the easy opening can lid, the bending angle of the inclined surface with respect to the bottom surface of the concave portion, outside the score line along the inclined surface of the concave portion, is set near the tip of the opening piece farthest from the rivet portion, and other portions. Partial compared to It is characterized in that smaller.
[0010]
According to the above configuration, the recess having the inclined surface and the bottom surface surrounded by the inclined surface is formed to improve the tension of the panel portion. Can be efficiently transmitted to the required part, and the score line is easily broken, and when the internal pressure of the can is increased in an unopened state, especially when the inner side of the concave portion is outside the score line, The bending angle of the inclined surface is made smaller at the portion near the tip of the opening (the portion near the outer periphery of the can lid) where the score line is likely to break than at the other portions, thereby facilitating deformation at this portion. This makes it possible to alleviate the concentration of the bending stress to the outside of the can lid due to the internal pressure on the score line portion, thereby making it difficult for the score line to break due to the internal pressure.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of an easy opening can lid according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows the entire upper surface of a can lid (before being fixedly wound around a can body) according to an embodiment of the can lid of the present invention, and FIG. FIG. 3 is an enlarged partial view of a side of the upper surface where the opening piece is located. FIG. FIG. 4 shows a molding state near the tip of the opening piece of the can lid. FIG. 5 shows a conventional example of an easy-opening can lid, and FIG. 6 shows (A) a normal case and (B) a case deformed by internal pressure, respectively, for a cross-sectional shape near the tip of an opening piece of the can lid. Fig. 3 shows a molding state near the tip of the opening piece of the can lid.
[0012]
The can lid 1 of the present embodiment is formed by press-forming from a thin plate of an aluminum alloy, and as shown in FIG. 1, a panel portion 2, a counter sink portion 3, and a flange portion 4 are integrally formed. An opening operation tab 6 formed separately from the main body portion is fixed by a rivet portion 5 formed substantially at the center of the substantially disk-shaped panel portion 2. Although not shown, a paint such as an epoxy-phenol resin, an epoxy-acrylic resin, a vinyl chloride resin, or the like is formed on the inner surface of the can lid 1 from the viewpoints of food hygiene, corrosion resistance, workability, flavor, and the like. , An organic coating of a resin film composed of one or more of thermoplastic resins such as polyethylene, polypropylene, polyester, polyamide, and ionomer is formed (in the case of a resin film, only one layer is formed). Or two or more layers, a biaxially stretched film, or a non-stretched film), and the back side of the flange portion 4 which is a portion fixedly fastened to the can body. , A sealant made of an organic polymer is applied and adhered.
[0013]
As shown in FIG. 2, the substantially disk-shaped panel portion 2 of the can lid 1 has a portion deviated to one side from the center of the panel portion 2 and an outer peripheral portion of the panel portion 2 from the vicinity of the rivet portion 5. The score line 7 extending from the start end 7a to the end 7b along the shape of the opening such that the length in the radial direction is extended to the vicinity and the length in the radial direction is longer than the length in the direction orthogonal to the score line. An unbreakable sub-score line 8 for reducing the concentration of stress on the main score line 7 at the time of forming the score line is provided inside the outer main score line 7 in a double line state. ) Is engraved, and the area surrounded by the score line 7 (the main score line that breaks at the time of opening) is a portion of the opening piece 10 that is pushed down into the can at the time of opening, and both ends of the score line 7 7a and 7b, between the panel portion 2 and the opening piece 10 at the time of opening. The hinge portion 9 connecting.
[0014]
While the opening piece 10 surrounded by the score line 7 is partially formed so as to be deviated to one side from the center of the substantially disk-shaped panel portion 2, as shown in FIG. One end of the tab 6 for pushing down the piece 10 is positioned above the opening piece 10 as a pushing-down end 6a, and the other end is separated from the opening piece 10 as a gripping portion 6b (with the opening piece sandwiching the rivet portion 5). (On the side opposite to 10), and is fixed by a rivet portion 5 located substantially at the center of the panel portion 2 outside the region of the opening piece 10.
[0015]
Further, the panel portion 2 in which the tab 6 is fixed by the rivet portion 5 and the opening piece 10 is formed so as to be surrounded by the score line 7 so as to include the area of the tab 6 and the opening piece 10 is inclined. And a concave portion 11 having a bottom surface 11a surrounded by the inclined surface 11b, and the area of the tab 6 and the opening piece 10 is completely surrounded by the continuous inclined surface 11b. The wire 7 and the rivet portion 5 are in a state formed on the bottom surface 11a. In addition, on the bottom surface 11a of the concave portion 11 of the panel portion 2, a horseshoe-shaped reinforcing projection 12 for providing rigidity to the portion of the opening piece 10 is formed in the area of the opening piece 10; Outside, near the end of the tab holding portion 6b, a finger insertion recess 13 for facilitating the grip of the tab holding portion 6b is connected to a part of the inclined surface 11b of the recess 11, and the bottom surface 11a of the recess 11 is formed. It is formed so as to be further depressed downward.
[0016]
In the present embodiment, the inclined surface 11b of the concave portion 11 continuously and completely surrounds the area of the tab 6 and the opening piece 10, but is not limited to such a structure, and extends along the periphery of the opening piece 10. Although it is necessary to make the inclined surface 11b continuous, a portion between the concave portion 11 and the counter sink portion 3 may be cut off in the vicinity of the tab gripping portion 6b, so that the pressure resistance is improved. Buckling can be easily caused on the grip 6b side of the tab located on the opposite side to the score line 7 when the internal pressure exceeding the pressure applied to the can lid prevents the score line 7 from being broken by the buckling. can do.
[0017]
By the way, in the can lid 1 of the present embodiment as described above, outside the score line 7 along the inclined surface 11 b of the concave portion 11, that is, except for the vicinity of the initial break portion close to the rivet portion 5 of the score line 7. Outside the generally U-shaped flat portion, the angle of the inclination of the inclined surface 11b with respect to the bottom surface 11a of the concave portion 11 is near the tip 10a of the opening piece 10 farthest from the rivet portion 5 (the portion near the outer periphery of the can lid). Thus, the angle is partially reduced (the inclination is gentle) as compared with the other parts.
[0018]
That is, in the present embodiment, specifically, as shown in FIG. 2, on the line of the virtual line X connecting the center of the rivet portion 5 and the tip 10a of the opening piece 10, as shown in FIG. Outside the substantially U-shaped portion of the score line 7 in the plane, a bending angle α of the inclined surface 11b having a substantially linear longitudinal section with respect to the substantially straight bottom surface 11a of the concave portion 11 (the inclination of the inclined surface 11b with respect to the bottom surface 11a). Angle) is 5 ° or less (about 3 ° in a specific example) at which bending is hardly conspicuous, and is symmetrical about the imaginary line X as a center line, and a circumferential angle θ at the center of the rivet portion 5 is set. Is approximately 40 °, the bend angle α gradually increases as the distance from the imaginary line X increases (so that the bend is conspicuous), and outside the range of the fan shape, it is shown in FIG. Like a traditional can lid Kicking Like the bending angle α of the inclined surface 11b relative to the bottom surface 11a in the mouthpiece near the tip, and has a bent angle of approximately 18 ° (15~25 °). The vertical cross-sectional shape of the bottom surface 11a or the inclined surface 11b may be a gently curved shape instead of a substantially linear shape. In this case, the bending angle is defined by a virtual straight line approximating the curved line.
[0019]
In the case where the concave portion 11 is press-formed in the panel portion 2 (the finger-inserting concave portion 13 is also press-formed), conventionally, the counter sink portion 3 and the flange portion 4 are formed, and the rivet portion is formed in the panel portion 2. The can lid on which the tabs 6, the score lines 7, and the reinforcing protrusions 12 are formed and the tabs 6 are not yet fixed is placed on the fixed members 21 and 22, as shown in FIG. 24 and the punch member 25 are moved downward, and by the punch member 25 having a pressing surface of a uniform height (excluding the molded portion of the finger insertion recess 13) along the entire periphery along the periphery of the bottom surface 11 a of the recess 11. By pressing the central portion of the panel portion 2, as shown in FIG. 5A, a concave portion 11 having an inclined surface 11b and a bottom surface 11a surrounded by the inclined surface 11b is formed. To the bottom surface 11a of the recess 11 Bending angle of the inclined surface 11b alpha (angle of inclination of the inclined surface 11b relative to the bottom surface 11a) has a substantially same angle all around the periphery of the recess 11.
[0020]
On the other hand, in the can lid 1 of the present embodiment, when the concave portion 11 is press-formed in the panel portion 2 as compared with the above-described conventional can lid, the can portion along the peripheral portion of the bottom surface 11a of the concave portion 11 is formed. With respect to the punch member 25 having a press surface, only a part of the press surface (a portion corresponding to the vicinity of the tip 10a of the opening piece 10) is inclined so as to be outwardly shallow as shown in FIG. In this case, as shown in FIG. 3A, the bending angle α of the inclined surface 11b with respect to the bottom surface 11a of the concave portion 11 is smaller (the inclination is gentler) near the tip 10a of the opening piece 10 than the other portions. It is formed so that it becomes. Although not shown, the bending angle of the inclined surface 11b with respect to the bottom surface 11a of the concave portion 11 at other portions outside the score line 7 (portions apart from the vicinity of the tip 10a of the opening piece 10) is shown in FIG. The bending angle is substantially the same as the conventional one shown in A).
[0021]
In the can lid 1 of the present embodiment having the above-described structure, the flange portion 4 is connected to the upper end opening edge of the can body with respect to the can body (can body) whose upper end is opened after the contents are filled. The state at the time of opening of the can lid 1, which becomes the upper end wall of the can container by being fixedly fastened to the can container, and thus becomes the upper end wall of the can container, will be briefly described below.
[0022]
At the start of the opening operation, first, from the state where the fingertip is inserted into the finger insertion recess 13 of the panel section 2 and the finger is hung on the tab holding section 6b, the tab holding section 6b is lifted, so that the rivet section 5 is used as a fulcrum. By pressing down on the tab holding portion 6b from the state in which the pressing-down end 6a of the tab is pressed down and the pressing-down end 6a of the tab is in contact with the panel portion 2 (the portion of the opening piece 10 near the rivet portion 5). The second kind of leverage works, and the lifting force acts as a force for pulling up the rivet part 5 to which the tab 6 is fixed, with the depressed end 6a of the tab and the contact point of the panel part 2 as a fulcrum, As a result, an initial break occurs in the score line 7 near the rivet portion 5.
[0023]
By raising the tab gripping portion 6b further from the state in which the score line 7 is initially broken, the first type of leverage works, and the tab 6 (pressing end) having both sides of the rivet portion 5 as fulcrums is provided. 6a), the score line 7, which has already been initially broken, is broken from its start end 7a toward the end 7b, and at the same time, the opening piece 10 is gradually pushed down into the can by the push-down end 6a of the tab. Finally, in a state where the portion between the start end 7a and the end 7b of the score line 7 is a hinge portion 9 and the opening piece 10 is connected to the panel portion 2, the entire opening piece 10 is pushed down into the can, The opening of the can lid 1 is completed.
[0024]
According to the can lid 1 of the present embodiment, which is opened as described above, the concave portion 11 having the inclined surface 11b and the bottom surface 11a surrounded by the inclined surface 11b has the inclined surface 11b at least around the opening piece 10. By forming the panel portion 2 so as to have a continuous state without a cutout portion and improving the tension of the panel portion 2, buckling is prevented from being preferentially generated around the opening piece 10. When the tab 6 is lifted at the time of opening and the score line 7 is initially broken, the lifting force on the tab 6 can be reduced without bending or deforming the portion of the panel portion 2 that contacts the depressed end 6a of the tab. It can be efficiently transmitted to a required portion of the can lid (near the rivet portion 5), and the score line 7 is easily broken.
[0025]
In addition, with respect to the inclined surface 11b of the concave portion 11 formed in the panel portion 2, the vicinity of the tip 10a of the opening piece 10 (the portion near the outer periphery of the can lid 1) is close to the bottom surface 11a of the concave portion 11 outside the score line 7. The bend angle (inclination angle) α of the inclined surface 11b is made smaller (slope) than the other portions, so that deformation in this portion is facilitated, and as a result, the can is left unopened. When the internal pressure of the can becomes high, especially in a portion where the score line 7 is easily broken near the tip of the opening piece 10, the outward bending stress of the can lid due to the internal pressure is reduced to concentrate on the score line 7 portion. Therefore, breakage of the score line 7 due to the concentration of bending stress is less likely to occur. In particular, by setting the bending angle α in the vicinity of the tip 10a of the opening piece 10 to 5 ° or less and making the bending in this portion almost inconspicuous, when the internal pressure of the can becomes high, the score line in this portion is increased. 7 can be sufficiently deformed, and as a result, the outward bending stress of the can lid due to the internal pressure can be surely alleviated from being concentrated on the portion of the score line 7.
[0026]
That is, when the internal pressure of the can is increased in the unopened state, in the vicinity of the tip 10a of the opening piece 10, in the conventional easy-open can lid, as shown in FIG. Since the boundary portion of the inclined surface 11b is largely bent and this portion is not easily deformed, the bending stress of the can lid due to the internal pressure acts intensively on the score line 7 portion, and the mountain line is folded at the score line 7 portion. The score line 7 is easily broken by this, whereas the easy-open can lid according to the present embodiment has the vicinity of the boundary between the bottom surface 11a of the concave portion 11 and the inclined surface 11b as shown in FIG. Is hardly bent and the portion outside the score line 7 is easily deformed, so that the bending stress of the can lid due to the internal pressure is reduced from being concentrated on the score line 7 portion, and the stress at the score line 7 portion is reduced. Requires less bending From, the score line 7 is not easily be broken.
[0027]
Note that, in the can lid 1 of the present embodiment, the bending angle α of the inclined surface 11b with respect to the bottom surface 11a of the concave portion 11 is partially reduced only near the tip 10a of the opening piece 10, so that the bending angle α The force applied to the tab 6 can be efficiently transmitted to a required portion of the can lid without impairing the overall tension of the panel portion 2 as compared with a case in which the pressure is reduced over the entire circumference of the concave portion 11. In addition, it is possible to sufficiently secure the opening property due to the breakage of the score line 7.
[0028]
As mentioned above, although one Embodiment of the easy opening can lid of this invention was described, this invention is not limited only to the specific structure shown in the said embodiment, For example, the shape of an opening piece May be approximately elliptical in the width direction (an approximately elliptical shape in which the length in the direction orthogonal to the rivet is longer than the length connecting the center of the rivet portion and the tip of the opening piece) or the tip of the opening is It may be a substantially heart-shaped shape with a slightly angular feeling, and a specific range near the tip of the opening piece can be appropriately changed depending on the difference in shape of the portion of the opening piece. Needless to say, the specific bending angle of the inclined surface with respect to the bottom surface of the concave portion in the vicinity of the tip can be appropriately changed depending on the difference in the breaking strength of the score line. .
[0029]
【The invention's effect】
According to the easy-opening can lid of the present invention as described above, the concave portion having the inclined surface and the bottom surface surrounded by the inclined surface is formed in the panel portion so as to include the area of the tab and the opening piece. By doing so, the operation by the tab at the time of opening can be efficiently transmitted to the required portion of the can lid, the score line can be easily broken, and the opening property of the can lid can be improved, By making the bending angle of the inclined surface with respect to the bottom surface of the concave portion smaller than the other portion near the tip of the opening piece, when the internal pressure of the unopened can increases, the outer pressure of the can lid due to the internal pressure increases. Can be prevented from concentrating on the score line near the tip of the opening piece, preventing the score line of the can lid from being inadvertently broken due to an increase in the internal pressure of the can. can do.
[Brief description of the drawings]
FIG. 1 is a top view showing the entirety of a can lid (before being fixedly wound around a can body) in an embodiment of an easy-open can lid according to the present invention.
FIG. 2 is an enlarged top view partially showing the side of the can lid shown in FIG. 1 with an opening piece in a state where a tab is omitted.
FIGS. 3A and 3B are cross-sectional views respectively showing (A) a normal case and (B) a case deformed by an internal pressure, with respect to a cross-sectional shape near the tip of an opening piece of the can lid shown in FIG. 1;
FIG. 4 is a sectional explanatory view showing a molding state near a tip of an opening piece of the can lid shown in FIG. 3 (A).
5A and 5B are cross-sectional views showing a cross-sectional shape near the tip of an opening piece of a conventional can lid, respectively, showing (A) a normal case and (B) a case deformed by an internal pressure.
FIG. 6 is an explanatory sectional view showing a molding state near the tip of the opening piece of the can lid shown in FIG. 5 (A).
[Explanation of symbols]
Reference Signs List 1 can lid 2 panel part 5 rivet part 6 tab 6a (tab) depressed end 6b (tab) grip part 7 score line 9 hinge part 10 opening piece 10a (opening piece) tip 11 recess 11a (recess) bottom 11b Slant surface α (of concave portion) Bending angle X of the inclined surface with respect to the bottom surface of the concave portion An imaginary line connecting the center of the rivet portion and the tip of the opening piece

Claims (2)

An opening piece surrounded by the score line is formed partially on one side of the substantially disk-shaped panel portion so as to leave a hinge portion between both ends of the score line, and a tab for pushing down the opening piece However, such that one end side is located above the opening piece as a depressed end, and the other end side is located away from the opening piece as a gripping portion, and is fixed by a rivet portion outside the area of the opening piece at substantially the center of the panel portion. A recess having an inclined surface and a bottom surface surrounded by the inclined surface is formed along the inclined surface of the concave portion in the easy opening can lid formed in the panel portion so as to include the area of the tab and the opening piece. Outside of the score line, the bent angle of the inclined surface with respect to the bottom surface of the concave portion is partially smaller near the tip of the opening piece farthest from the rivet portion as compared with other portions. Easy opening can . 2. The easy-open can lid according to claim 1, wherein a bend angle of the inclined surface with respect to a bottom surface of the concave portion is 5 ° or less on an imaginary line connecting a center of the rivet portion and a tip of the opening piece.

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