US20120043324A1

US20120043324A1 - Container with Reduced, Peel-Off-Force Tear Configuration

Info

Publication number: US20120043324A1
Application number: US13/211,881
Authority: US
Inventors: Gerald J. Baker; Alvin Widitora
Original assignee: Silgan Containers LLC
Current assignee: Silgan Containers LLC
Priority date: 2010-08-18
Filing date: 2011-08-17
Publication date: 2012-02-23

Abstract

A container assembly includes a can, a can end, and a sheet which hermetically closes an access opening in the can end. The can end includes an opening for accessing the contents of the container. This opening is hermetically sealed closed by a sheet sealed to the end about the periphery of the opening with a closed-loop of adhesive. The sheet preferably includes a tab and a weakened or score line which causes the sheet to tear across the seal at an angle less than 90 degrees to the seal such that the sheet pulls away from the can end along a line generally parallel to the loop where the sheet is being separated from the can end.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This patent application claims the benefit of U.S. Provisional Patent Application No. 61/374,703, entitled Container with Reduced, Peel-Off-Force Tear Configuration, filed Aug. 18, 2010, which is incorporated herein by reference in its entirety.

BACKGROUND

The present invention relates generally to the field of easy-open containers. More specifically, the present invention relates to cans and can ends for container assemblies which can be opened without the use of an opening tool, such as a can opener.

SUMMARY

One embodiment relates to a container end having a metal rim including an inwardly extending flange with a rolled edge which defines an opening in the end, the metal rim including a thermoplastic layer and an area extending into the opening, and a foil with a thermoplastic layer. The foil covers the opening and includes a weakened formation and a tab formed by at least a portion of the formation. A closed-loop seal is provided which has a central axis. The seal is formed by heating selected portions of the layers to seal the foil to the rim such that the tab is substantially located over the area. The formation is configured to promote tearing of the foil across the seal when a pulling force is initially applied to the tab and separation of the foil from the seal in a direction generally parallel to the central axis of the seal after the foil is torn across the seal. Also provided is a seal extension extending from the closed loop between the area and the tab.
One embodiment relates to a metal container assembly, including a metal can end and a metal can body. The metal can end includes a metal rim, a sheet, and a closed-loop adhesive seal. The metal rim includes an inwardly extending flange with a rolled edge that defines an opening in the end. The sheet covers the opening so that the rolled edge is rolled toward the sheet. The closed-loop adhesive seal hermetically seals the sheet to the flange. The sheet further includes a tab and a weakening line in the vicinity of the tab. The weakening line is configured so that the sheet tears across the seal substantially when the tab is initially pulled by the user at an angle less than 90 degrees. The metal can end is fastened to the open end of the can by overlapping a portion of the can with a portion of the metal rim, and bending the portions into a sealed joint.
Another embodiment relates to a container assembly, including a can, a can end, a metal foil sheet, and an adhesive. The can has an open end and the can end is fastened to the open end. The can end has at least one opening defined by a periphery. The metal foil sheet closes the opening defined by the periphery. The adhesive attaches the metal foil sheet to the periphery of the opening to hermetically close the opening. The adhesive is able to resist at least a force of 20-30 pounds per square inch of the portion of the foil covering the opening. The adhesive includes at least one portion that is resistant to the removal of the foil that is less than the resistance to remove at least another portion of the adhesive. The metal foil portion is configured to be pulled with a force to remove the foil from the opening, the majority of the force is directed to at least one portion.
Still another embodiment relates to a container end, including a generally circular metal flange, a sheet, and an adhesive bead structure. The generally circular metal flange includes an inwardly extending flange that defines an opening in the end. The sheet covers the opening. The adhesive bead structure hermetically seals the sheet to the flange. The bead structure is configured in a generally spiral form to provide concentric areas of adhesive on at least portions of the flange. The sheet is formed to permit independent removal of the sheet from the concentric areas, reducing the force required to separate the sheet from the opening.
Yet another embodiment relates to a container end including, a metal rim, a sheet, and a closed-loop adhesive seal. The metal rim has an inwardly extending flange that defines an opening in the end. The sheet covers the opening. The closed-loop adhesive seal hermetically seals the sheet to the flange. The seal has a seal strength that is reduced at a weakened location along the seal. The sheet includes a tab and a weakening line in the vicinity of the tab that generally crosses the weakened location to cause the foil to tear across the seal at the weakened location.

BRIEF DESCRIPTION OF THE FIGURES

The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements, in which:

FIG. 1 is a perspective view of a container assembly in a first configuration according to an exemplary embodiment.

FIG. 2 is a side view of the container assembly of FIG. 1.

FIG. 3 is a bottom view of the container assembly of FIG. 1.

FIG. 4 is a top view of the sheet shown at the top of the container shown in FIG. 1.

FIG. 5 is a top view of the end of the container of FIG. 1 without the sheet shown.

FIG. 6 is a top view of the container end of FIG. 1 including the sheet.

FIG. 7 is a sectional view taken along line 7-7 in FIG. 6.

FIG. 8 a sectional view taken along line 8-8 in FIG. 6.

FIG. 9 is a view showing the sheet partially torn to expose the opening in the end.

FIG. 10 is a view showing the sheet torn to expose the opening in the end to a greater degree that shown in FIG. 9.

FIG. 11 is a view showing the sheet partially torn to expose the opening in an end having a strainer feature.

FIG. 12 is a view showing the sheet torn to expose the opening in the end with a strainer feature to a greater degree than shown in FIG. 11

FIG. 13 is a top view of an alternate embodiment of a container end including an alternate embodiment of the sheet and seal.

FIG. 14 is a top view of an alternate embodiment of a container end including an alternate embodiment of the sheet and seal.

DETAILED DESCRIPTION

Before turning to the figures, which illustrate the exemplary embodiments in detail, it should be understood that the present invention is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting.
Referring to FIG. 1, a container assembly 100 includes a can 102 (e.g., can body) and a can end 104 (e.g., top). The can 102 includes a bottom 106 (e.g., second can end) and side wall 108 extending vertically from the bottom 106. In some embodiments, the sides 108 form a cylindrical tube and include ridges 110. The can 102 defines a volume internal thereto, in which contents (e.g., solid items and/or liquid), such as cut fruit suspended in syrup or beans in water, of the container assembly 100 may be stored. A label (not shown) may be printed and/or adhered to the sides 108 of the can 102, identifying the contents of the container assembly 100.
In some embodiments, the container assembly 100 is a three-piece assembly, formed from three main parts. The bottom 106 and side wall 108 are separately stamped and fastened together, such as by forming the side wall 108 into a cylindrical tube, and crimping an end of wall 108 to the bottom 106. According to an exemplary embodiment, a sealant surface layer or gasket (e.g., rubber coating) may be positioned between the crimped portions, to improve the seal therebetween. With the bottom 106 and wall 108 fastened together, the can 102 includes an open end, which may be covered by the can end 104. According to an exemplary embodiment, bottom 106 an end 104 may be formed from a single metal sheet using a stamping process, and fastened to side wall 108. Edges internal to the openings may be rolled.
In other embodiments a container assembly is a two-piece assembly, where a can body (e.g., having sides and a bottom) is formed by a stamping and/or drawing process, from a single sheet of metal (e.g., aluminum, coated steel, etc.), and a can end is separately formed, stamped from another sheet of metal. In some embodiments, components or features of a container assembly are formed by stretching molding, die cast, blown, or otherwise formed.
The container assembly 100 may be fully assembled, as shown in FIG. 1, partially assembled, or may be an assembly that is configured to be, but not yet fastened together (e.g., assembly of kit components). For example, some embodiments may include a container assembly including a can end and a sheet configured to be coupled thereto. Other embodiments may include a container assembly including a can (e.g., body) and a can end, fastened together, but without a sheet coupled to the can end. Other contemplated embodiments include still other container assemblies, having components that are fastened together and separate components that are unfastened kits.
Referring again to FIG. 1, sides 108 of the can 102 extend upward to form an open end of the can 102, to which the can end 104 is fastened. According to an exemplary embodiment, the can end 104 is fastened to the open end of the can 102 by overlapping a portion of the can 102 with a portion of the can end 104, and bending (e.g., crimping and/or rolling) the portions into a sealed joint assembly and a rim of the container assembly 100. A sealant or gasket may be positioned between the portions, such as via a coating of sealant material (e.g., elastic material, pliable material, rubber, plastic, polyethylene, etc.) on either or both of the portions. Although the sealed joint of FIG. 1 shows a particular arrangement of bending and overlapping, other arrangements of bending and overlapping may be used for fastening the can end 104 to the sides 108 of the can 102. In still other contemplated embodiments, the can end 104 is otherwise fastened to the can 102 (e.g., glued, welded, pressure fit, etc.) or formed integrally therewith. The can end 104 may be fabricated all, or in part, from a metal, and may joined to the sides 108 with a rolled joint or soldered joint (i.e., double seam). This rolled joint may be rolled upwardly or downwardly.
With reference to FIGS. 1, 4, and 5, in one embodiment a sheet 126 is provided. The sheet 126 will be applied to cover and hermetically seal the opening 118 in the can end 104, as will be further described below. The sheet 126 includes a weakening formation 128. The weakening formation 128 includes a radially inward cut 130 directed substantially towards a center 132 of the sheet 126 and a score 134 extending substantially perpendicularly radially outward from the inward cut 130. The cut 130 and score 134 define a tab 136 which is configured to rupture the weakening formation 128 and allow for removal of the sheet 126, as will be discussed further below. Additionally, in other embodiments the cut 130 may instead be a score or the score 134 may instead be a cut.
FIG. 5 illustrates a can end 104 with the sheet 126 removed. In one embodiment, the can end 104 includes a rim portion 116 which defines a generally rounded opening 118. In particular, opening 118 may be defined by a rolled edge 119 (see FIGS. 7 and 8). Depending upon the content or use of the can, rolled edge 119 may not be necessary if exposure of a sheared edge of opening 118 is acceptable. The rim portion 116 includes a rolled edge 120 and a flange 122 extending inwardly from the rolled edge 116 and defining the opening 118. The flange 122 also includes an area 124 extending farther radially inwardly into the opening 118. The can end 104 is preferably formed from any suitable metal (e.g., steel, aluminum, etc.) and covered with a thermoplastic layer as necessary. In one embodiment the thermoplastic layer being polypropylene. In other embodiments, the thermoplastic layer may be formed of any suitable material known in the art.
The sheet 126 is in one embodiment preferably a metal foil covered with a thermoplastic layer. In one embodiment, the foil is an aluminum foil and the thermoplastic layer is a polypropylene layer. The sheet 126 is preferably size to completely cover the opening 118, as illustrated in FIG. 6.
With reference to FIG. 6, sheet 126 is sized to cover the opening 118, oriented with the weakening formation 128 overlaying the inwardly extending area 124, and placed on top of the flange 122 of the rim portion 116. The sheet 126 is hermetically sealed to the flange 122 with a closed loop seal 138. The closed loop seal 138 may be formed by heat fusing or thermowelding the sheet 126 to the flange 122, by the application of adhesive to one or both of the sheet 126 and the rim portion 116 with or without heat sealing, or by any other suitable means known in the art. Additionally, a seal extension 140 extends from the closed loop seal 138 underneath a portion of the tab 136, holding a portion of the tab 136 to the inwardly extending area 124 of the flange 122. It should be understood that an adhesive seal is a seal which adheres sheet 126 to flange 122 and operates with sheet 126 to hermetically seal opening 118 closed. With reference to FIG. 1, in other embodiments, an alternate seal extension 141 may be used in place of seal extension 140. The alternate seal extension 141 may be a long extended triangular configuration, as illustrated in FIG. 1, extending down the tab 136. Additionally, other alternate seal extensions of various shapes, dimensions, thicknesses, widths, etc., are also envisioned. Any suitable configuration of seal extension may also be used, including a seal extension having a much narrower width than the sealing bead sealing the remainder of the can end 104.
In the canning process, upon filling a can 102, the can end 104 is attached to the can 102 to form the container assembly 100. The container assembly 100 and its contents are then typically cooked in a retort process to temperatures of at least 220 to 250 degrees Fahrenheit, creating pressures within the container assembly 100 of at least twenty to thirty pounds per square inch. The closed loop seal 138 preferably is configured to withstand pressures and temperatures within these ranges and maintain the hermetic seal between the sheet 126 and the flange 122 under these conditions, without overpressure during the cooking process.
FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 6 and illustrates the sheet 126 hermetically sealed to the flange 122 by the closed-loop seal 138. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 6 and similarly illustrates the closed loop seal 138. With reference to FIGS. 7 and 8, the closed-loop seal 138 extends substantially around the opening 118. As discussed above, sheet 126 may be fastened to the flange 122 with an adhesive (e.g., adhesive layer, fused coatings, coating, glue, etc.) attached to the sheet 126 and/or to the can end 104. In some embodiments, the adhesive 138 may include a thermoplastic layer or coating on the sheet 126—such as on a side of the sheet 126 that is to be fastened to the can end 104. Heating of the adhesive 138, such as by a heated press, temporarily melts the adhesive 138, which subsequently solidifies, bonding the sheet 126 to the can end 104. The can end 104 may also have a thermoplastic adhesive layer on the side to be attached to the sheet 126, and, with the use of a heated press or other heating means, may similarly be bonded to the sheet 126. By selectively heating the thermoplastic layers on sheet 126 and flange 122, the configuration of seal 138 can be selected or modified depending upon the can end shape (e.g., round, square, rectangular, oval, etc.), the sheet, can and/or can end materials, and/or particular retort process parameters. In some embodiments, the sheet 126 seals the can end 104 such that the container assembly 100 is hermetically sealed, helping to preserve perishable contents of the container assembly 100.
Depending upon the use and application of assembly 110, the material used to adhere the sheet 126 to can end 104 may not be uniform in adherence strength and/or material type. By selective placement of adhesive types, the peeling and pressure handling characteristics of the sheet 126 can be controlled. Additionally, in other embodiment the thermoplastic layer on the sheet 126 and/or the can end 104 may be omitted, and the sheet 126 may instead be adhered to the can end 104 by placing adhesive on the sheet 126 and/or the can end 104 and applying the sheet 126 to the can end 104. Other suitable mechanisms known in the art for adhering the sheet 126 to the can end 104 are also contemplated. Similarly, the portion of the tab 136 adhered by the seal extension 140 to the area 124 of the flange 122 may be formed in the same way as the closed loop seal 138 or in various other ways known in the art differently from the closed loop seal 138.
With reference to FIG. 9, the removal of the sheet 126 to expose the opening 118 in the can end 114 is illustrated. The closed loop seal 138 defines a central axis 142 extending longitudinally along the closed loop seal 138. To remove the sheet 126, a user will grasp the tab 136 and urge the tab 136 upwardly. The sheet 126 will tend to break the closed loop seal 138 at a break point 146 proximate the score 134 in the sheet 126. When a pulling force is initially applied to tab 136, weakening formation 128 promotes tearing of the sheet 126 across seal 138. Depending on the configuration of formation 128, sheet 126 material and/or the seal 138 configuration, the sheet 126 will tear across seal 138 at an angle of less than or equal to 90 degrees to central axis 142. After tearing across seal 138, sheet 126 will be removed by breaking seal 138 in a direction along the central axis 142 of the closed loop seal 138 (as indicated by arrow 144). Other directions are also contemplated. The outer portion of the tab 136 will tend to follow the central axis 142. As the sheet 126 is removed, the leading edge of separation 148 (e.g., fold-over of sheet 126) is formed generally perpendicular to the central axis 142, will tend to move in a direction generally parallel to the central axis 142 of the closed loop seal 138 (though other directions are also contemplated) around the perimeter of the can end 104 as a user continues to urge the tab 136 in the direction indicated by arrow 150 in FIG. 10. The user may continue to urge the tab 136 around the entire perimeter of the can end 114, separating the sheet 126 entirely from the rim portion 116, at which point the opening 118 is completely exposed and the sheet 126 may be disposed of.
In another embodiment, the tab 136 formed in the weakening formation 128 may further include a pull ring coupled to the tab 136 to allow for gripping and pulling the tab 136 by a user. Additionally, in other embodiments, other known removal devices are also contemplated.
In another embodiment, with reference to FIGS. 11 and 12, a can end 204 is shown attached to can 202 as illustrated. The can end 204 defines a first opening 218 (e.g., large opening, hole, aperture, etc.) and one or more second openings 252 (e.g., a plurality of small openings, i.e., strainer opening) defined by a flange area projection 254 projecting radially inwardly from the flange 222. The first opening 218 is wide enough to pour solid contents of the container assembly 200 therethrough. In some embodiments, the first opening 218 has an area that is slightly less than half the area of the can end 204, and is formed in a crescent shape, a half-circle, or otherwise shaped, the size of the first opening 218 being defined by the area 224 projecting from the flange 222 upon which the tab 236 is seated in the closed configuration, and the projection 254 projecting radially inwardly. While the area 224 and the projection 254 are illustrated as separate, it is contemplated that these could be formed into an integral combined unit. Additionally, the projection 254 may be located at any circumferential location around the can end 204. Each second opening 252, in one embodiment, is sized for straining, such that the solid contents of the container assembly 200 are generally too large to fit therethrough. In some embodiments, each second opening 252 is less than one fifth the size of the first opening 218, such as less than one tenth the size of the first opening 218. However, in other embodiments the first 218 and second 252 openings are the same size.
As is illustrated in FIGS. 11 and 12, the removal of the sheet 226 from the container end 204 may be done by a user in substantially the same way as in the previous embodiment, with a user grasping the tab 236 and urge the tab 236 upwardly and along the central axis of the closed loop seal 238 as indicated by arrow 244, with the sheet 226 tending to break the closed loop seal 238 at a break point 246 proximate the score 234 in the sheet 226, the outer portion of the tab 236 tending to follow the closed loop seal 238 and the leading edge of separation 248 tending to move parallel to the closed loop seal 238 around the perimeter of the can end 204 as a user continues to urge the tab 236 in the direction indicated by arrow 250 in FIG. 12. The weakening formation 228 may also be configured in various ways to allow for the break point 246 to be directed at various different angles, allowing for tearing of the sheet 226 in various different ways for various different effects and applications.
In another embodiment of the seal, as illustrated in FIG. 13, the closed loop seals 138, 238 of previous embodiments are replaced with a spiral closed loop seal 337. The spiral closed loop seal 337 seals the sheet 326 to the container end 304 in a concentric circular spiral pattern of seals progressing radially inwardly. The circular pattern may meet in a hermetically sealing complete seal at a seal junction 339 which may be disposed anywhere around the perimeter of the can end. Thus, in this embodiment, the seal at the break point 346 may be of decreased width as compared to previous embodiments, thus allowing for a user to more easily break the seal using the tab 336 at this point. When a user pulls on the tab 336, the sheet 326 will tend to pull away from the spiral closed loop seal 337 in a series of strips following the perimeter of the container end and the concentric portions of the spiral closed loop seal 337. Once the tab 336 has followed all of these concentric portions, the sheet 326 will be generally free of the container end 304 and may be discarded.
In another embodiment, as illustrated in FIG. 14, a sheet 426 may be used in conjunction with an alternate embodiment of a can end 404. The can end 404 includes a flange area portion 454 that defines, along with the periphery of the can end 404, a semi-circular first opening 418 (e.g., large opening, hole, aperture, etc.). In its interior, the flange area portion 454 also defines one or more second openings 452 (e.g., a plurality of small openings, i.e., strainer opening). A sheet 426 is preferably positioned over the can end 404 with a tab 436 located adjacent the second openings 452 over a portion of the flange area portion 454. The tab 436 may be defined by a weakening portion 428, similar to that of previous embodiments. The sheet 426 is preferably sealed with two continuous seals. A first continuous seal 470 surrounds and hermetically seals the first opening 418. The second continuous seal is located around the second openings 452, hermetically sealing the second openings 452. These continuous seals 470, 472 may be of any suitable type known in the art.
The weakening portion 428 is preferably configured such that when a user pulls the tab 436, the sheet 426 tends to break across the second continuous seal 472 exposing the second openings 452. As the user continues to pull the tab 436 around the periphery of the can end 404, in one embodiment the sheet 426 will tend to separate from the can end 404 along both the radially inner and radially outer portion of the second continuous seal 472 concurrently exposing the second openings 452. Once the second openings 452 are totally or partially exposed and the tab 436 has reached the second openings 452 distal from the original location of the tab 436, in some embodiments the removed portion of the sheet 426 may encounter a second weakening portion 474. This second weakening portion 474 may comprise scoring or any other suitable weakening of the sheet 426 at any suitable angle, proximate the corner of the semi-circular first opening 418 that is farthest from the initial location of the tab 436.
This second weakening portion 474 is configured to allow for breaking across a portion of the first continuous seal 470. The second weakening portion 474 may be configured to allow the sheet 426 to break at various different angles across the first continuous seal 470. Once the first continuous seal 470 has been broken, the sheet 426 may continue to be removed from the first opening 418 by a user continuing to pull the tab 436 and/or the sheet 426 around the periphery of the can end 404 until the sheet 426 is completely removed from the can end 404. As the user continues to pull, the sheet 426 will be freed from the can end 404 as in previous embodiments. The sheet 426 may tear across the first opening 418 or may tend to follow the first continuous seal 470 depending on the application and configuration of the sheet 426.
As previously discussed, container assembly 100 is formed from metal, such as tin-coated steel, or aluminum. In some embodiments, the can 102 is formed from aluminum and the can end 104 is formed from tin-coated steel. In other embodiments, other metals or materials (e.g., high-temperature plastic, ceramic, etc.) may be used to form some or all of the container assembly 100. In some embodiments, the sheet 126 is a metal foil (e.g., aluminum foil, steel foil, etc.), having a thickness substantially between 1/1000 to 1/100-inch. The metal foil may include an outer (top, outside, etc.) layer (e.g., coating) of polyethylene terephthalate (PET), a middle layer (e.g., substrate) of foil, and a bottom layer (e.g., 70 microns thick) of polypropylene, where the outer layers are applied via a coextrusion process. The polypropylene is configured to be heated and used as an adhesive. In other embodiments, the metal foil includes additional layers of different materials, and/or layers of similar materials in different arrangements (e.g., order). In still other embodiments, the sheet 126 is plastic or composite (e.g., plastic foil with one or more coatings thereon).
Additionally, other container proportions are contemplated. For example, contemplated embodiments include ⅞ size, 1-“picnic” size, size 303, size 10, and other size cans, such as those standard sizes and shapes that are commercially available in the United States and abroad. Such cans may be configured to hold 4 ounces, 10.5 ounces, and even over 100 ounces of liquid. Some embodiments are cylindrical, while other embodiments are rounded-rectangular (e.g., box container), and still other embodiments include other container assembly geometries. Although the can 102 is illustrated as a round cylinder, other can shapes are contemplated, along with other can end 104 shapes to suitably couple to the can 102.
The construction and arrangements of the container assembly, as shown in the various exemplary embodiments, are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Some elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process, logical algorithm, or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.

Claims

What is claimed is:

1. A container end, comprising:

a metal rim including an inwardly extending flange with a rolled edge which defines an opening in the end, the metal rim including a thermoplastic layer and an area extending into the opening;

a foil with a thermoplastic layer, the foil covering the opening, the foil including a weakening formation and a tab formed by at least a portion of the formation;

a closed-loop seal having a central axis and formed from the layers to seal the foil to the rim such that the tab is substantially located over the area, wherein the formation is configured to promote tearing of the foil across the seal when a pulling force is initially applied to the tab and separation of the foil from the seal in a direction generally parallel to the central axis of the seal after the foil is torn across the seal; and

a seal extension extending from the closed loop between the area and the tab.

2. The container end of claim 1, wherein the seal includes a weakened area adjacent to the weakened formation to further promote tearing of the seal across the seal.

3. The container end of claim 1, wherein the foil is an aluminum foil and the thermoplastic layer is polypropylene.

4. The container end of claim 2, wherein the seal is configured to prevent breach of the hermetic seal when a force of at least 20-30 pounds per square inch is applied to the portion of the foil covering the opening.

5. The container end of claim 4, wherein the seal is further configured to prevent breach of the hermetic seal when the end is exposed to at least 220 to 250 degrees Fahrenheit.

6. A metal container assembly comprising:

a metal can end including:

a metal rim including an inwardly extending flange which includes a rolled edge with defines an opening in the end,

a sheet which covers the opening such that the rolled edge is rolled toward the sheet, and

a closed-loop adhesive seal which hermetically seals the sheet to the flange, wherein the sheet includes a tab, and a weakening line in the vicinity of tab configured to promote tearing of the sheet across the adhesive seal; and

a metal can body having an open end, wherein the can end is fastened to the open end of the can by overlapping a portion of the can with a portion of the metal rim and bending the portions into a sealed joint.

7. The metal container of claim 6, wherein the tab is oriented to be pulled in a direction generally parallel to the central axis of the adhesive seal.

8. The metal container of claim 7, wherein the sheet is a metal foil having a thermoplastic layer.

9. The metal container of claim 8, wherein the flange includes a thermoplastic layer and the adhesive seal is formed from a portion of the thermoplastic layers by selectively heating the overlapping layers.

10. The metal container of claim 9, wherein the seal has a seal strength which is reduced, relative to the majority of the seal, at a weakened location along the seal, and the weakening line is located substantially at the weakened location to cause the foil to tear across the seal substantially at the weakened location.

11. The container of claim 10, wherein the seal is formed from first and second adhesives wherein the second adhesive is weaker than the first adhesive and the second adhesive forms a portion of the seal at the weakened location.

12. The container of claim 10, wherein the adhesive seal is formed with at least first and second cross-sections wherein the second cross-section in smaller than the first cross-section and the adhesive located at the weakened location has the second cross-section.

13. The container of claim 9, wherein the flange has an increased area, all or a portion of the weakening line is located above the increased area, and the metal foil includes a tab at least partially defined by the weakening line.

14. The container of claim 13, wherein the seal includes a projection located between the tab and increased area of the flange.

15. A container assembly, comprising:

a can having an open end;

a can end attached to the open end, having at least one opening defined by a periphery,

a metal foil sheet configured to close the opening; and

an adhesive which attaches the foil to the periphery of the opening to hermetically close the opening, the adhesive being configured to resist at least a force of 20-30 pounds per square inch of the portion of the foil covering the opening;

the metal foil including a weakened formation configured to promote tearing of the foil across the adhesive the foil is pulled to remove the foil from the can end.

16. The container assembly of claim 15, the adhesive includes at least one portion which has resistance to removal of the foil which is less than the resistance to removal of at least another portion of the adhesive.

17. The container assembly of claim 16, wherein the at least one portion has a reduced amount of adhesive.

18. The container assembly of claim 16, wherein the can is fabricated from metal.

19. The container assembly of claim 16, wherein the can is fabricated from a non-metallic material.

20. The container assembly of claim 15, wherein the can end is fastened to the open end of the can by overlapping a portion of the can with a portion of the can end and bending the portions into a sealed joint.

21. The container assembly of claim 19, wherein the sheet is integrally formed from a flexible material, and peelable from the can end.

22. The container assembly of claim 20, wherein the flexible material is a polypropylene aluminum.

23. The container of claim 15, wherein the foil sheet and the periphery include a thermoplastic layer, the periphery includes an increased area, and the adhesive is the combination of portions of the thermoplastic layers which are formed by selectively heating overlapping layers into a closed-loop of adhesive with a projection located at the increased area.

24. A container end, comprising:

a generally circular metal flange including an inwardly extending flange which defines an opening in the end;

a sheet which covers the opening;

an adhesive bead structure which hermetically seals the sheet to the flange, the bead structure being configured in a generally spiral form to provide concentric areas of adhesive on at least portions of the flange, the sheet being formed to permit independent removal of the sheet from the concentric areas thereby reducing the force required to separate the sheet from the opening.

25. The container end of claim 24, wherein the sheet is a metal foil sheet which includes at least one weakening line which facilitates tearing of the foil to permit independent removal of the sheet from the concentric areas.

26. The container end of claim 25, wherein the adhesive is a thermoplastic.

27. The container end of claim 26, wherein the sheet is generally circular and is sealed to the can end around the perimeter of the sheet.

28. The container end of claim 27, wherein the sheet includes a tab extending therefrom, configured to facilitate peeling of the sheet from the can end.

29. A container end, comprising:

a metal rim including an inwardly extending flange which defines an opening in the end;

a sheet which covers the opening; and

a closed-loop adhesive seal which hermetically seals the sheet to the flange, the seal, wherein the sheet includes a tab, and a weakening line in the vicinity of tab to cause the foil to tear across the seal substantially at the weakened location.

30. The container end of claim 29, wherein the seal is formed from first and second adhesive layers located on the sheet and rim, respectively.

31. The container end of claim 30, wherein the adhesive is a thermoplastic material.

32. The container end of claim 31, wherein the adhesive seal is formed to have a projection extending from the closed-loop toward the tab.

33. The container end of claim 32, wherein the weakening line crosses the adhesive loop at an angle less than 90 degrees.

34. The container end of claim 32, wherein the flange includes a rolled edge which defines the boundary of the opening.

35. The container end of claim 34, wherein the sheet is formed from a metal foil.

36. The container end of claim 32, wherein the flange includes a widened location generally located below the tab and the weakened location.