Patent Publication Number: US-2012043324-A1

Title: Container with Reduced, Peel-Off-Force Tear Configuration

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.