Tamper Evidencing Metal Foil Container Closure

Abstract

A tamper evident metal foil closure for a container which provides visual evidence of tampering in the form of damage to the metal foil (e.g. tearing) and evidence of temperature tampering of the metal foil when heat is used to remove and reseal the metal foil. Containers sealed with this novel metal foil closure make it more difficult to tamper with or remove the container contents and then return the container for a refund.

Description

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 2B-2B 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 3B-3B 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 4B-4B 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.

Claims

1. A tamper evidencing closure for a container comprising: a metal ring;a metal foil sealed to the ring on one side of the metal foil with a thermoplastic adhesive; anda heat-sensitive, color-changing ink applied to one of the ring or 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.

2. The closure of claim 1, wherein the 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 to span and seal close the opening.

3. The closure of claim 2, wherein the metal foil includes a weakening formation adjacent to the interior flange.

4. The closure of claim 3, wherein the closure further includes a pull-tab joined to the metal foil generally adjacent to the weakening formation.

5. The closure of claim 4, wherein the weakening formation is a groove extending adjacent to the edge of the interior flange.

6. The closure of claim 1, wherein the ink changes color at temperatures above 150 to 160 degrees F.

7. The closure of claim 6, wherein the melting point of the adhesive is from 180 to 190 degrees F.

8. The closure of claim 2, wherein the double seam flange has a top side and a bottom side which engages a respective container and the interior flange has a top surface which extends from the topside and a bottom surface which extends from the bottom side, the metal foil being adhered to the topside.

9. The closure of claim 2, wherein the double seam flange has a top side and a bottom side which engages a respective container and the interior flange has a top surface which extends from the topside and a bottom surface which extends from the bottom side, the metal foil being adhered to the bottom side.

10. A food container comprising: 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 including a double seam flange adjacent to an interior flange which defines an opening, the metal foil being adhered to the interior flange with the thermoplastic adhesive to span and seal close the opening; anda heat-sensitive, color-changing ink applied adjacent to the adhesive and on an exterior surface of the container defined by of one of the metal ring or foil, wherein the temperature at which the ink changes color is above ambient air temperature and below the melting point of the adhesive, wherein 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.

11. The closure of claim 10, wherein the metal foil includes a weakening formation adjacent to the interior flange.

12. The closure of claim 11, wherein the closure further includes a pull-tab joined to the metal foil generally adjacent to the weakening formation.

13. The closure of claim 12, wherein the weakening formation is a groove extending adjacent to the edge of the interior flange.

14. The closure of claim 10, wherein the ink changes color at temperatures above 150 to 160 degrees F.

15. The closure of claim 14, wherein the melting point of the adhesive is from 180 to 190 degrees F.

16. The closure of claim 10, wherein the double seam flange has a top side and a bottom side which engages the top edge and the interior flange has a top surface which extends from the topside and a bottom surface which extends from the bottom side, the metal foil being adhered to the topside.

17. The closure of claim 10, wherein the double seam flange has a top side and a bottom side which engages the top edge and the interior flange has a top surface which extends from the topside and a bottom surface which extends from the bottom side, the metal foil being adhered to the bottom side.

18. A food container comprising: a cylindrical container body defined by a body from which a cylindrical wall extends to a top edge;a metal ring including a double seam flange adjacent to an interior flange which defines an opening, wherein 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; anda metal foil which spans the bottom side, the bottom surface and the opening to cover the opening; wherein 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.

19. The food container of claim 18 further comprising a thermoplastic adhesive which bonds the metal foil to the metal ring.

20. The food container of claim 18, wherein the metal foil includes a weakening formation adjacent to the interior flange and a pull-tab joined to the metal foil adjacent to the formation.