Patent Publication Number: US-2020277100-A1

Title: Tamper Evidencing Metal Foil Container Closure

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
     This application is a continuation of International Application No. PCT/US2019/012036, filed Jan. 2, 2019, which claims the benefit of and priority to U.S. Provisional Application No. 62/612,835, filed on Jan. 2, 2018, both which are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND OF THE INVENTION 
     Many containers are used to contain valuable content such as high value food (e.g. baby formula). In the case of food, as with many types of content, there is a concern with tampering and in the case of baby formula there is a problem with parties removing and replacing the content with a similar-mass, low value content and returning the container for a refund. The present disclosure relates to a metal foil container closure which is difficult to open or remove without causing a visual indication that the metal foil has been disturbed. In particular, the closure includes a metal foil closure configured to rip or tear if the adhesive holding the metal foil in place is not first heated, and includes a heat sensitive ink which changes color upon heating. 
     SUMMARY OF THE INVENTION 
     One embodiment of a tamper evidencing closure for a container includes a metal ring, a metal foil sealed to the ring on one side of the metal foil with a thermoplastic adhesive, and a heat-sensitive, color-changing ink applied to the metal foil. The ink is applied on the opposite side of the metal foil adjacent to the adhesive. The temperature at which the ink changes color is above ambient air temperature and below the melting point of the adhesive. 
     Another embodiment provides a food container having a cylindrical container body defined by a base from which a cylindrical wall extends to a top edge; a metal foil, a thermoplastic adhesive, a metal ring and a heat-sensitive, color-changing ink. The metal ring includes a double seam flange adjacent to an interior flange which defines an opening and the metal foil is adhered to the interior flange by the thermoplastic adhesive to span and seal close the opening. The heat-sensitive, color-changing ink is applied to the metal foil on the opposite side of the metal foil adjacent to the adhesive wherein the temperature at which the ink changes color is above ambient air temperature and below the melting point of the adhesive. The double seam flange is rolled into a seal with the cylindrical container at the top edge such that the container, the seal, the metal ring, the adhesive and the metal foil are joined to form a hermetically sealed enclosure having a predetermined volume. 
     Another embodiment provides a food container closure for a cylindrical container body defined by a body from which a cylindrical wall extends to a top edge. The closure includes a metal ring including a double seam flange adjacent to an interior flange which defines an opening. The double seam flange has a top side and a bottom side and the interior flange has a top surface which extends from the topside and a bottom surface which extends from the bottom side. A metal foil spans the bottom side, the bottom surface and the opening to cover the opening. After the closure is applied to the container, the double seam flange and the top edge are formed into a seam having the metal foil captured between the double seam flange an the top edge of the container. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       This application 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 top perspective view of a container with an embodiment of a tamper evidencing closure; 
         FIG. 2A  is a top view of a first embodiment of the closure; 
         FIG. 2B  is a sectional view of the closure in  FIG. 2A  taken along line  2 B- 2 B in  FIG. 2A ; 
         FIG. 3A  is a top view of a second embodiment of the closure; 
         FIG. 3B  is a sectional view of the closure in  FIG. 3A  taken along line  3 B- 3 B in  FIG. 3A ; 
         FIG. 4A  is a top view of a third embodiment of the closure; 
         FIG. 4B  is a sectional view of the closure in  FIG. 4A  taken along line  4 B- 4 B in  FIG. 4A ; 
         FIG. 5  is a top perspective view of the top portion of a container with the second embodiment of the closure; 
         FIG. 6  is a sectional view of the top portion of the container in  FIG. 5  taken along line  6 - 6 ; and 
         FIGS. 7A and 7B  are top views of the embodiments of the metal closure ring with various opening shapes, interior flange configurations, and foil tear locations. 
     
    
    
     DETAILED DESCRIPTION 
     Before turning to the figures, which illustrate the exemplary embodiments in detail, it should be understood that the present application 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 generally to the Figures, the main elements of a tamper evidencing closure  8  for a container  10  (e.g.  2  or  3  piece metal can) include: 
     A metal ring  12 ; 
     A metal foil  14 ; 
     A thermoplastic adhesive bead  16 ; and 
     A heat-sensitive, color-changing ink bead  18 . 
     In one embodiment the metal ring  12  includes a double-seam interface rim  20 , a flange  22  which defines the shape of the opening  24  to the container  10  and provides an adherence surface  26  at which the foil  14  is adhered to the ring  12  by bead  16 . Ring  12  also includes a transition  26  between rim  20  and flange  22 . The particular configurations of rim  20  and  26  would be selected based upon a particular can  10  configuration and material (e.g. steel, aluminum, tin-plate, etc.). 
     Referring to  FIGS. 2A-4B , various sealing arrangements of the flange  22 , foil  14 , adhesive bead  16  and ink bead  18  are illustrated in detail. Flange  22 , foil  14  and adhesive bead  16  are sealed together to form a hermetic seal between flange  22  and foil  14 . For purposes of this invention “hermetic seal” means a seal which maintains a seal against flow of gases such as those in environmental air where such flow is below the limit specific by applicable laws and regulations for the content of the container with which the tamper evidencing closure would be used. For example, for powdered baby formula, the hermetic seal must meet the requirements for a hermetic seal used for food products as defined by applicable industry or government standards. By way of further example, adhesive bead  16  may be a poly propylene thermoplastic adhesive and ink bead  18  may be a thermoset ink with a color transition temperature of 160 degrees F. and preferably between 150 and 200 degrees F. Depending upon the particular ink used for bead  18 , the transition temperature would preferably be above ambient air temperature and below the melting point of the adhesive for bead  16 . By way of modification, a second ink bead could be placed adjacent to the ink bead  18  which does not change color within the temperature ranges discussed herein. The color of the second bead would be the same as the bead  18  prior to being subjected to the transition temperature. The purpose of this second bead would allow an observer to know that bead  18  was subjected to a temperature change because it would no longer have the same color as the second bead. 
     Referring specifically to the embodiment of  FIGS. 2A and 2B , the closure  8  is configured such that foil  14  includes a pull tab  28  and is hermetically sealed to the top of flange  22  by a continuous adhesive bead  16  initially applied to one of the flange  22  or foil  14 . After the foil  14  is positioned on flange  22 , heat is applied to flange  22 , foil  14  and bead  16  to form the hermetic seal by causing the adhesive to transition from its solid state to at least a total or partially liquid state, and then cool. After the hermetic seal is cooled below the color transition temperature of the ink used for bead  18 , ink bead  18  is applied adjacent to the adhesive bead  16  to be visible from the exterior of a respective container  10 . As shown in  FIGS. 2A and 2B , bead  18  is deposited on top of foil  14  above bead  16 . By way of modification, a second ink bead could be placed adjacent to the ink bead  18  which does not change color within the temperature ranges discussed herein. The color of the second bead would be the same as the bead  18  prior to being subjected to the transition temperature. The purpose of this second bead would allow an observer to know that bead  18  was subjected to a temperature change because bead  18  would no longer have the same color as the second bead. 
     For purposes of this disclosure, “adjacent” means that bead  18  is close enough to bead  16  so that enough heat energy is transferred to bead  18  to permanently change the color of bead  18  when the temperature of adhesive bead  16  reaches a level so the adhesive in bead  16  transitions to or begins to transition to a liquid state. As will be appreciated, the heat energy transfer rate will depend upon the particular metal from which ring  12  and foil  14  are fabricated. Accordingly, the distances which would fall into this definition of “adjacent” may vary depending upon the particular materials used in closure  8 . 
     Referring specifically to the embodiment of  FIGS. 3A and 3B , the closure  8  is configured such that foil  14  includes a pull tab  28  and is hermetically sealed to the bottom of flange  22  by a continuous adhesive bead  16  initially applied to one of the flange  22  or foil  14 . After the foil  14  is positioned on flange  22 , heat is applied to flange  22 , foil  14  and bead  16  to form the hermetic seal by causing the adhesive to transition from its solid state to at least a total or partially liquid state, and then cool. After the hermetic seal is cooled below the color transition temperature of the ink used for bead  18 , ink bead  18  is applied adjacent to the adhesive bead  16  to be visible from the exterior of a respective container  10 . As shown in  FIGS. 3A and 3B , bead  18  is deposited on top of flange  22  above bead  16 . By way of modification, a second ink bead could be placed adjacent to the ink bead  18  which does not change color within the temperature ranges discussed herein. The color of the second bead would be the same as the bead  18  prior to being subjected to the transition temperature. The purpose of this second bead would allow an observer to know that bead  18  was subjected to a temperature change because bead  18  would no longer have the same color as the second bead. 
     Referring specifically to the embodiment of  FIGS. 4A and 4B , the closure  8  is configured such that foil  14  includes a pull tab  28  and is hermetically sealed to the bottom of flange  22  by a continuous adhesive bead  16  initially applied to one of the flange  22  or foil  14 . However, in this embodiment, foil  14  extends over all, or substantially all, of the bottom surface of ring  12 . After the foil  14  is positioned on ring  12 , heat is applied to flange  22 , foil  14  and bead  16  to form the hermetic seal by causing the adhesive to transition from its solid state to at least a total or partially liquid state, and then cool. After the hermetic seal is cooled below the color transition temperature of the ink used for bead  18 , ink bead  18  is applied adjacent to the adhesive bead  16  to be visible from the exterior of a respective container  10 . As shown in  FIGS. 4A and 4B , bead  18  is deposited on top of flange  22  above bead  16 . By way of modification, a second ink bead could be placed adjacent to the ink bead  18  which does not change color within the temperature ranges discussed herein. The color of the second bead would be the same as the bead  18  prior to being subjected to the transition temperature. The purpose of this second bead would allow an observer to know that bead  18  was subjected to a temperature change because bead  18  would no longer have the same color as the second bead. 
     As discussed in further detail below, the various configurations of foil  14  provide for scoring  30  which facilitates destruction/tearing of foil  14  when the foil is peeled away from flange  22  during opening of container  10 . Given that an object of the present disclosure is to provide a tamper evidencing closure, it is believed that sealing the foil  14  to the bottom of flange  22  as provided in the embodiments of  FIGS. 3A to 4B , it will be would be more difficult to reseal a container  10  after tampering even if the foil  14  could be heated and removed. Inserting and re-sealing foil  14  to the bottom side of flange  22  after the foil  14  and the content of container  10  are contaminated or removed would be difficult given that it is unclear how pressure could be provided from within container  10  during resealing. Depending upon the success of the embodiments shown in  FIGS. 3A to 4B  it may be possible to forgo the use of color changing ink as discussed above. 
     The embodiment of  FIGS. 4A and 4B  go a step further and capture the foil in the double/triple seam as shown in  FIG. 6 . Referring specifically to  FIG. 6 , ring  12  is shown after closure  8  is hermetically sealed/seamed to container wall  11 . In particular, double-seam rim  20 , the top of wall  11  and the portion of foil  14  covering the inside of rim  20  are rolled into a seam  32  as shown using conventional seaming equipment. Typically, when the rim  20  and top of wall  11  are seamed to form a hermetic seal, the seam is referred to a double seam. However, where 3 layers are seamed as shown in  FIG. 6  the seam may be referred to as a triple seam. 
     Referring to the exploded views in  FIGS. 2B, 3B, 4B, 6 , all or a portion of scoring  30  is formed in foil  14  near the boundary of the opening  24  defined by flange  22 .  FIG. 7A  illustrates additional scoring around the perimeter of opening  24  and generally perpendicular to the edge of the opening  24  to facilitate tearing of foil  14  when pealed from flange  22 .  FIG. 7B  illustrates an alternative to a circular opening  24  by providing a generally D-shaped opening. 
     Additional configurations useable for the opening  24  shapes, interior flange configurations, and foil tear locations  30  are shown in U.S. Patent Publication Nos. 2011-0226771, filed Mar. 17, 2011, 2011-0272417 filed on Jul. 20, 2011, 2012-0043324 filed on Aug. 17, 2011, and 2012-0043324 filed Aug. 17, 2011, respectively, the entirety of each being incorporated herein by reference. 
     In various exemplary embodiments, except for the glue and ink beads discussed above, the relative dimensions, including angles, lengths and radii, as shown in the Figures are to scale. Actual measurements of the Figures will disclose relative dimensions and angles of the various exemplary embodiments. Various exemplary embodiments include any combination of one or more relative dimensions or angles that may be determined from the Figures. Further, actual dimensions not expressly set out in this description can be determined by using the ratios of dimensions measured in the Figures in combination with the express dimensions set out in this description. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the disclosure (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure. 
     Further modifications and alternative embodiments of various aspects of the disclosure will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only. The construction and arrangements, 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 disclosure.