EP1055607A2

EP1055607A2 - Container lid

Info

Publication number: EP1055607A2
Application number: EP00304197A
Authority: EP
Inventors: Hirotsugu c/o Ishida Co. Ltd Mori; Yoshio Ishida Co. Ltd Shiga Int.Facil. Iswasaki; Akira Kizukabutodanchi 6 302 Morita
Original assignee: Ishida Co Ltd
Current assignee: Ishida Co Ltd
Priority date: 1999-05-18
Filing date: 2000-05-18
Publication date: 2000-11-29
Also published as: CA2308730A1; JP2000326968A; EP1055607A3

Abstract

To suppress flapping in container lids having a (synthetic polymer) resin layer. The container lid (1) in being attached to the opening in container body (2) is of resin in at least a layer, and is provided with a panel (5), a seal-opening grip (12), a flange (6) and a score (7). The panel (5) is for covering the opening in the container body (2). One end of the grip (12), which is furnished on the top of the panel (5), is fixed edge-ward on one part of the panel (5). The flange (6) is formed on the outer periphery of the panel (5), and is fitted to the brim of the container body (2) opening. The score (7) consists of an annular groove formed between the panel (5) and the flange (6). On its rear-half section, the panel (5) then has bending portion(s) by slit(s) (5b) that when opening the seal are for bending back along fold lines that intersect with the seal-opening direction.

Description

BACKGROUND OF THE INVENTION

Technical Field

The present invention relates to container lids; in particular to container lids fitted onto container body openings and being of (synthetic polymer) resin in at least a layer.

Description of Related Art

One way of handling food items is to put them into can-shaped containers that are sealed with a sealing lid for storage or display in shops. Containers of this sort are furnished as a container body and a lid that covers the container body opening. The lid then has a panel portion that covers the opening in the container body, and a flange portion formed on the circumference of the panel portion and which is attached to the rim of the container opening. An annular groove (score) for breaking the seal is formed between the panel and flange portions, and furthermore a seal-breaking grip is furnished on the panel toward one end. Thus, tugging on the seal-breaking grip shears the portion of the lid along the score, which breaks open the seal on the container.
In containers of this sort are those in which all or the chief portions are formed from metallic materials, and those that are formed by injection molding synthetic polymer resin. Some lid constructions employing synthetic polymer resins are formed only of resin, and some are formed of a gas barrier layer in which aluminum foil or like metal foil is the principal constituent, and a resin layer coated onto one or both surfaces of the gas barrier layer.
In breaking open the seal on hermetically closed containers "flapping" has to be avoided. Flapping herein means when drawing the seal-opening terminal end of the panel away from the flange as the seal is opened, the panel portion, which until then had been elastically deformed, springing as it returns to its original form, which force splashes the contents and splatters the surroundings.
With metallic lids the entirety or principal parts of which are formed of metallic raw materials, when opening the seal, the panel gets bent back and plastically deformed. And since when the panel is yanked away from the flange it does not return to its original flat condition, flapping does not occur.
Nevertheless, in the case of metal lids, there is a possibility material that is suspected as a hormone-disrupting substance (so-called environmental hormones) will elute from coating agents generally on the inner face or from the packing. In the case of metal lids, moreover, after the seal has been opened the lid edge is dangerous.
Herein, lids employing resin are recently receiving attention. Since in the case of lids employing resin the elasticity of the lid is itself high, however, when the panel portion is pulled off the flange portion, the force tending to return it to its original flat condition is strong, and it ends up flapping.
Reducing the elastic force by making the thickness of the lid thinner would suppress flapping. If the lid thickness is thinned, however, irregularities in the lid are liable to arise in retorting, which degrades the value of the merchandise.

SUMMARY OF THE INVENTION

An object of the invention is to suppress flapping in container lids being of resin in at least a layer.
Another object of the present invention is to make the work of breaking open the seal smooth, and moreover to suppress flapping.
A container lid as determined by a first aspect of the invention is furnished with a panel member that attaches to a container body opening and that is of synthetic polymer resin in at least a layer; a seal-breaking grip; a flange portion; and a scored portion. The panel member is for covering the opening in a container body. The grip is provided on top of the panel member, wherein one end is fixed edge-ward to the panel member. The flange portion is formed circumferentially on the panel member and fits on the brim of the container body opening. The scored portion consists of an annular groove formed between the panel member and the flange portion. Then in the rear-half section of the panel member lengthwise along its seal-opening direction is a bending portion that bends back along a bend-back line intersecting the seal-opening direction when the seal is broken open.
The flange portion on this container lid attaches to the rim on the opening in the container body, wherein the panel member covers the container body opening. In breaking open the seal, pulling up the seal-breaking grip tears the panel member away from the flange portion along the scored portion from toward the one end of the panel member. In the course of the seal-opening operation, the bending portion in the panel member bends back. The bending back of the panel member liberates stress that has accumulated due to elastic deformation by working open the seal until that point. Accordingly, when the entire panel member is finally torn away from the flange portion, force tending to return it to its original flatness is slight, suppressing flapping.
Herein, flapping is suppressed while guaranteeing the lid's thickness.
A container lid as determined by a second aspect of the invention is, in container lids in the first aspect, one in which the bending portion is a section of the panel member in which the bending rigidity varies in the seal-opening direction.
Varying the bending rigidity of the panel member in the seal-opening direction facilitates bending back the panel member in that section.
A container lid as determined by a third aspect of the invention is, in container lids in the first or second aspect, one in which the bending portion of the panel member is provided between the rear-half third of the length along the seal-opening direction, and the terminal end in the seal-opening direction.
Providing the bending portion in a position thus smoothes the operation of breaking open the seal and meanwhile suppresses flapping.
A container lid as determined by a fourth aspect of the invention is, in container lids in any of the first through third aspects, one in which the bending portion of the panel member is a slit formed extending in a direction that intersects the seal-opening direction.
Herein, the bending rigidity of the section in which the slit is formed is low by comparison to the other sections, and accordingly the panel member bends back on the slit section in the course of breaking open the seal. As described previously, the bending back of the panel member liberates stress that has accumulated in the panel member, which suppresses flapping.
A container lid as determined by a fifth aspect of the invention is, in container lids in the fourth aspect, one in which the panel member has a metallic foil layer and a (synthetic polymer) resin layer coated onto the surface of the metallic foil layer. The slit then is half or more the thickness of the resin layer in depth, but not so as to reach the metallic foil layer.
Herein, the lid's strength and its gas-barrier properties due to the metallic foil are maintained, and yet the bending portion is readily formed by the slit. Further, the resin layer is continuous on either side of the slit, which facilitates injection molding.
A container lid as determined by a sixth aspect of the invention is, in container lids in the fourth aspect, one in which the panel member has a metallic foil layer and a (synthetic polymer) resin layer coated onto the surface of the metallic foil layer. Then, the mid-section of the slit lengthwise is of depth to expose the metallic foil layer, but either end lengthwise is not so deep as to expose the metallic layer.
This thus deepens the depth of the slit constituting the bending portion, enabling the panel member to be bent back with still less force. Further, in either end of the slit lengthwise both sides of the slit are continuous, which, likewise as noted above, facilitates injection molding.
A container lid as determined by a seventh aspect of the invention is, in container lids in any of the first through third aspects, one in which the bending portion of the panel member is a bulge provided extending in a direction that intersects the seal-opening direction.
Herein, the bending rigidity of the section in which the bulge is formed is high by comparison to the other sections, and in the course of breaking open the seal, the panel member accordingly bends back on the section immediately before the bulge. As described previously, the bending back of the panel member liberates stress that has accumulated in the panel member, which suppresses flapping.
From the following detailed description in conjunction with the accompanying drawings, the foregoing and other objects, features, aspects and advantages of the present invention will become readily apparent to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a configurational view in section through a container lid according to one embodiment of the present invention;
Fig. 2 is a plan view of the container lid;
Fig. 3 is a view in section through the line III-III in Fig. 2;
Fig. 4 is an enlarged, fragmentary view in section through a second slit;
Figs. 5 and 6 are configurational views in section for explaining a seal-breaking operation;
Fig. 7 is a plan view of a container lid according to another embodiment;
Fig. 8 is a plan view of a container lid according to yet another embodiment;
Fig. 9 is a plan view of a container lid according to still another embodiment;
Fig. 10 is a configurational view in section through a container lid according to a further embodiment;
Fig. 11 is a plan view of a container lid according to a yet other embodiment; and
Fig. 12 is a plan view of a container lid according to further embodiment still.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In Fig. 1, a container lid (noted hereinafter simply as lid) 1 according to one embodiment of the present invention, and a portion of a container body 2 to which the lid 1 is attached, are shown. Note that Fig. 1 is a view in section through line I-I in lid 1 shown in Fig. 2, which is a plan view. Further, Fig. 3 is a view in section through line III-III shown in Fig. 2 in lid 1.
The lid 1 is for covering the opening 2a in the container body 2 and sealing beverage items put into the container body 2, and has a disk-shaped panel 5 and a flange 6 formed on the outer periphery of the panel 5. At the border between them, a score 7 consisting of an annular groove having a predetermined depth is formed.
The panel 5 is formed from, depicted in Fig. 4, a gas-barrier-inherent film 10 furnished on the container body side, in which (synthetic polymer) resin 10b is laminated onto either side of an aluminum foil 10a that is gas-barrier inherent; and a synthetic polymer layer 11 that is coated on the surface of the film 10 by injection-molding. It should be understood that foils of other metals such as iron, or other synthetic polymers having gas-barrier properties may be provided instead of the aluminum foil 10a. Further, polypropylene, polyethylene, polyester, polyamide, polycarbonate, and polysterol can be employed as the synthetic polymer layer 11.
A seal-opening grip 12 is formed extending in the seal-opening direction (direction A in Fig. 2) on the upper face of the panel 5. The grip 12 on one end is joined via a thin hinge 13 to the surface of the panel 5 where the seal is initially broken, and on its other end is a hole 12a into which the finger is caught when opening the seal. Further, the grip 12 apart from the fixed portion on the one end is disposed at a predetermined clearance from the surface of the panel 5.
The grip may also be, for example, a separately formed gripping member 21 as shown in Fig. 12, post-welded ultrasonically or otherwise to a lid 22 without a tab.
In the panel 5, on the side where the seal is initially broken and adjacent the hinge 13, a first slit 5a is formed in a direction orthogonal to the seal-opening direction. Further, flanking the grip 12 its other-end side, a pair of retainer legs 14 is formed adjoining the grip 12; tips of the retainer legs 14 are made to interlock into interlock recesses 12b formed in corresponding places on the grip 12. Interlocking the retainer legs 14 into the interlock recesses 12b enables the grip 12 to be retained in position approximately parallel with the surface of the panel 5.
In addition, a protuberance 15 is formed adjoining the tip on the one-end side of the grip 12. The protuberance 15 has, formed outside the first slit 5a, a ridge 15a formed to extend along the first slit 5a, and pressing reinforcement 15b formed to extend away from the middle of the ridge 15a. Also, a crack is provided between the ridge 15a and the one-end of the grip 12 to enable the grip to be lifted up.
Furthermore, in the other end (where opening the seal finishes) of the panel 5, a second slit 5b (bending portion) of predetermined length is formed parallel with the first slit 5a.
The second slit 5b is for lowering the bending rigidity in the seal-opening direction compared to the other portions of the panel 5; the panel 5 gets bent back in the course of opening the seal due to the second slit 5b. The second slit 5b is formed between a pair of nubs 16 provided a bit inside the score 7. As shown enlarged in Fig. 4 the depth h of the second slit 5b is 1/2 or more the thickness t of the resin layer 11, preferably not so deep as to reach the gas-barrier film 10. In other words, it is preferably made to be
t/2 ≤ h < t.
Also, the pair of nubs 16 facilitates maintenance in stacking lids 1 for storage, and is formed at the same height as the height of the protuberance 15 formed on the one end.
The first slit 5a, second slit 5b, grip 12, retainer legs 14, protuberance 15 and nubs 16 formed on the panel 5 herein are formed by injection molding simultaneously with the panel 5, and are unitarily molded.
The flange 6 has the gas-barrier film 10, which continues from the panel 5 inner surface, and (synthetic polymer) resin layer 20 coated onto the obverse surface of the film 10 by injection molding. Moreover, as will be later described, the resin layer on the flange 6, and the resin layer 11 of the panel 5 are formed simultaneously by injection molding, and are unitarily molded.
The flange 6 is for attachment to the brim of the opening in the container body 2, and has: an inner cylindrical portion 6a along the circumferential portion inner wall of the container body 2; an upper surface portion 6b extending outward from the upper end of the inner cylindrical portion 6a; and an outer cylindrical portion 6c extending downward from the circumferential edge of the upper surface portion 6b. Inner cylindrical portion 6a and the upper surface portion 6b are thus made as a dual-layer structure from the film 10 and the resin layer 20, whereas the outer cylindrical portion 6c is formed only from the resin layer 20.
The score 7 is formed at the boundary between the inner cylindrical portion 6a of the flange 6 and the outer circumferential edge of the panel 5; and while most of its annular groove, as shown in Fig. 1, is formed to a depth that exposes the gas-barrier film 10, a portion thereof, as shown in Fig. 3, is made to a depth that does not expose the film 10. In this section, that is, the resin layer 11 of the panel 5 and the resin layer of the flange 6 are continuous. This consequently enables molding the resin layer 11 of the panel 5 and the resin layer of the flange 6 at the same time integrally, as noted earlier, during injection-molding of the resin.
How a lid configured this ways works when the seal is broken and it is opened will be explained.
When breaking the seal, the hole 12a in the grip 12 is caught with the finger, and the other-end side of the grip 12 is pulled up off the upper face of the panel 5. The grip 12 turns on the hinge 13 as the center and the end face of the one-end side thereof abuts on the ridge 15a of the protuberance 15. When the grip 12 is lifted further from this state, the pressing reinforcement 15b on the protuberance 15 pushes down the area of the panel 5 further outward than the slit 5a, which accordingly causes the score 7 to break partially, as shown in Fig. 5.
Next, when the grip 12 is pulled upward, the panel 5 detaches from the flange 6 going along the score 7. During the detachment of the panel 5, when the detaching region of the panel 5 reaches the second slit 5b, since the bending rigidity of the section in which the second slit 5b is formed is low compared to the remaining portion, the score 7 is not ripped--at first the panel 5 is bent back on the second slit 5b section. This state is depicted in Fig. 6. Bending back the panel 5 liberates stress that has built up in the panel 5, which has been subject to elastic deformation by the operation until that point of breaking open the seal.
Continuing to pull the panel 5 up following this rends the remainder of the score 7 so that the panel 5 is completely torn away from the flange 6. Just prior to the end of the panel 5 in the direction in which the seal-opening terminates being torn away from the flange 6, bending back of the panel 5 in the second slit 5b section liberates stress that has built up in the panel 5. Consequently, after the end of the panel 5 in the seal-breaking termination direction has been torn away from the flange 6, force by which the panel 5 would tend to revert to its original flatness is slight, which suppresses bounciness. Flapping is therefore prevented.

Other Embodiments

(a) Positions and forms of the second slit 5b are not limited to the foregoing embodiment. As shown in Fig. 7 for example, the slit may extend beyond the outer sides of the pair of nubs 16, and be of length to reach the flange 6. In this case, the depth of the second slit 5b overall may, as described earlier, be made t/2 ≤ h < t; moreover, the depth may vary in the middle and in either end. If the depth is to vary, the middle portion would presumably be made deep enough to expose the gas barrier film 10, and either end made same as the just-noted t/2 ≤ h < t. Bending back is accordingly made easier still.
Further, as Fig. 8 depicts, the second slit 5b may be formed further toward the end in the direction in which the seal opening terminates. The position in which the second slit 5b is formed is preferably in the rear-half section, with respect to the overall length D in Fig. 2, in the seal-opening direction, i.e., the section D/2 that is the rear-half--more preferably in the section D/3 in the rear half. The operation of breaking open the seal will accordingly go more smoothly, and flapping will be still further suppressed.
Moreover, if the second slit 5b is put near the midsection, the panel 5 gets bent back early in the duration of the seal-opening operation, preventing the panel 5 from curl-rolling in the course of opening the seal. In other words, since the rigidity of the resin-manufactured or resin-layer-containing lid is low, it can happen that while pulling the grip 12 when breaking open the seal, the midsection of the panel 5 near the grip 12 curves upward, making it hard to break open the seal. Forming the second slit 5b in a position near the midsection, however, prevents the panel 5 from bending back and the midsection of the panel 5 from curving upward early during the seal-opening operation.
Further, a plurality of slits 5b may be formed in parallel at a predetermined spacing in the rear-half section in the seal-opening direction, as shown in Fig. 9.
(b) Yet another embodiment is depicted in Figs. 10 and 11.
In this embodiment, instead of forming second slit(s), toward the end of the panel 5 in the seal-breaking termination direction, the thickness of a certain area (the area indicated by diagonal lines in Fig. 11) 5c is formed thicker than the thickness of the area 5d that in the seal-breaking direction is more toward the start. This partial area 5c in which the thickness is greater is made as a bulge that extends in a direction orthogonal to the seal-opening direction. Therefore, the thickness of all of the partial area 5c may be made thicker. Or, only a linear part thereof may be made to bulge, extending in a direction orthogonal to the seal-opening direction, such that it corresponds to the section in which the foregoing second slit 5b is formed.
In a configuration thus, the bending rigidity of the area 5c is high compared to the other area 5d. Consequently, when the tearing away of the panel 5 moves from the area 5d to the area 5c as the seal is opened, the seal-opening handling resistance increases sharply. The panel 5 in between the area 5d and the area 5c (precisely, just before the area 5c, or the terminating end of the area 5d) gets bent back. Thus, likewise as in the foregoing, stress that has built up in the panel 5 is liberated; and on continuing the seal-opening manipulation further to tear the panel 5 completely away from the flange 6, flapping is suppressed.
(c) In the foregoing embodiments, the panel 5 and the flange 6 are formed with the gas-barrier film and resin layers, but may be formed of a resin layer only, or in tri-layer structures that contain resin layer(s).
(d) The form of the seal-breaking grip may, as shown in Fig. 12, be a separately molded grip post-welded to the lid 22. With regard to the number of the slits 5a, furthermore, they are not limited in that, as the same figure indicates, a plurality of the slits may be formed.
According to the present invention as in the foregoing, a bend-back portion that crosses the seal-opening direction is provided in a part of the lid, which prevents flapping when breaking open the seal on the lid being of resin in at least a layer.
While only selected embodiments have been chosen to illustrate the present invention, to those skilled in the art it will be apparent from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. Furthermore, the foregoing description of the embodiments according to the present invention is provided for illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

Claims

A container lid (1) for attachment to a container body opening, the lid comprising synthetic polymer resin, in at least a layer, and further comprising:

a panel member (5) for covering the container body opening;

a seal-breaking grip (12) provided on top of the said panel member, wherein one end of the said grip is fixed to said panel member towards a front edge thereof;

a flange portion (6) formed circumferentially on said panel member for fitting brim-wise onto the container body opening;

a scored portion (7) consisting of an annular groove formed between said panel member and said flange portion; wherein

said panel member comprises, in its rear-half section as measured lengthwise along the seal-opening section (A), a bending portion which, during seal-opening, bends back along a bend-back line intersecting the seal-opening direction.
A container lid according to claim 1, said bending portion being a section of said panel member wherein bending rigidity varies in the seal-opening direction.
A container according to claim 1 or claim 2, wherein said bending portion is provided in the rear-third section of said panel, as measured lengthwise along the seal-opening direction.
A container lid according to any preceding claim, wherein said bending portion comprises a slit (5b) formed in said panel member and extending in a direction intersecting the seal-opening direction.
A container according to claim 4, wherein said panel member comprises a metallic foil layer (10a) and a synthetic polymer resin layer (10b) coated superficially onto said metallic foil layer and wherein said slit is formed in said resin layer and has a depth of at least half the thickness of said resin layer but does not reach the metallic foil layer.
A container according to claim 4, wherein said panel member comprises a metallic foil layer (10a) and a synthetic polymer resin layer (10b) coated superficially onto said metallic foil layer and wherein said slit is formed at least in said resin layer and a mid-section of said slit, in a lengthwise direction, is of sufficient depth to expose and said metallic foil layer, and either end of said slit, in a lengthwise direction, is not of sufficient depth to expose said metallic foil layer.
A container according to claim 1, wherein said bending portion comprises a bulge (5c) provided in said panel member, said bulge extending in a direction intersecting the seal-opening direction and along or rearwards from said bend-back line.