WO2007140215A2

WO2007140215A2 - Membrane lid with recessed tab, and container incorporating same

Info

Publication number: WO2007140215A2
Application number: PCT/US2007/069557
Authority: WO
Inventors: Alan Richards
Original assignee: Sonoco Development, Inc.
Priority date: 2006-05-26
Filing date: 2007-05-23
Publication date: 2007-12-06
Also published as: US20070272693A1; WO2007140215A3

Abstract

A membrane lid (30) having a recessed ring pull tab (34). The membrane lids comprises a permanently deformable layer (e.g., metal foil or thin sheet metal) having a disk portion (32) and a tab (34) projecting from the outer periphery of the disk portion. The tab is folded back onto the upper surface of the disk portion. A region of the disk portion underlying the folded-back tab defines a depression (40) and the tab (34) is folded back such that it is recessed within the depression. A sealing material is provided on the lower surface of the membrane lid for sealing the lid to a metal ring (20) of a container.

Description

MEMBRANE LID WITH RECESSED TAB, AND CONTAINER INCORPORATING

SAME

BACKGROUND OF THE INVENTION

The invention relates to containers having a metal ring affixed to the top end of the container so as to define an annular surface that encircles the top opening of the container and to which a flexible membrane closure or lid is sealed to initially seal the container. Such membrane lids often have a tab that can be grasped and pulled to facilitate peeling the membrane lid from the metal ring.

The tabs on such membrane lids represent potential difficulties during handling of the membrane lids by automated machinery. The tabs may initially lie flat against the upper surface of the membrane lids, but handling can cause the tabs inadvertently to be lifted and consequently the tabs can get caught in the machinery and cause a jam or can get torn off.

BRIEF SUMMARY OF THE INVENTION

The present invention addresses this problem by providing a membrane lid having a recessed ring pull tab. The membrane lid comprises a permanently deformable layer (e.g., metal foil or thin sheet metal) having a disk portion and a tab projecting from the outer periphery of the disk portion. The tab is folded back onto the upper surface of the disk portion. A region of the disk portion underlying the folded-back tab defines a depression and the tab is folded back such that it is recessed within the depression. A sealing material is provided on the lower surface of the membrane lid for sealing the lid to a metal ring of a container.

The membrane lid in one embodiment comprises a deformable layer of metal, and a sealant layer joined to a lower surface of the disk portion of the deformable layer. The tab

-1 - AttyDktNo: 031599/320835 does not have the sealant layer. The disk portion and the tab comprise a single piece of metal, being formed by a process of die-cutting (or similar process) from a sheet of metal.

In accordance with one embodiment of the invention, an outer edge of the tab is rolled to provide a cut-resistant outer edge. The tab advantageously is ring-shaped, defining a finger hole therethrough. An inner edge of the hole in the tab is also rolled to provide a cut- resistant inner edge.

The disk portion of the lid can have a non-smooth (e.g., dimpled, pebbled, or waffled) configuration, if desired or necessary in a particular application. Alternatively, the disk portion can be smooth.

A container in accordance with one embodiment of the invention comprises a container body having a side wall that terminates in a top edge circumscribing an opening of the container body. A metal ring is seamed to the top edge of the container body. The metal ring includes an annular portion that extends radially inwardly from the container body and defines an upper surface. The metal ring has an inner edge circumscribing an aperture through the metal ring for access to the interior of the container body. A membrane lid is sealed to the upper surface of the metal ring. The membrane lid has a configuration as described above, including a depression and a tab folded back into the depression.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRA WING(S)

Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

FIG. 1 is a perspective view of a container in accordance with one embodiment of the invention;

FIG. 2 is a view similar to FIG. 1, showing the membrane lid being peeled away from the metal ring;

FIG. 3 is a top elevation of a metal ring and membrane lid assembly in accordance with one embodiment of the invention, for attachment to a container;

FIG. 4 is a magnified top elevation of the tab region of the membrane lid; and

-2- AttyDktNo: 031599/320835 FIG. 5 is a cross-sectional view through the metal ring and membrane lid assembly.

DETAILED DESCRIPTION OF THE INVENTION

The present inventions now will be described more fully hereinafter with reference to the accompanying drawings in which some but not all embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

A container 10 in accordance with one embodiment of the invention is shown in FIGS. 1 and 2. The container comprises a container body 12 having a side wall 14 that encircles the interior space in the container body. The side wall extends upwardly and terminates in a top edge 16 that circumscribes a top opening of the container body. Affixed to the top edge 16 of the container body is a metal ring 20. The metal ring can be affixed by double-seaming, wherein an outer curled region 22 of the metal ring is rolled outwardly along with a flange formed on the top edge of the container body. Double-seaming processes are well known and hence do not require detailed description herein. The metal ring includes an annular portion 24 that is generally planar and extends radially inwardly from the curled region 22. The annular portion defines an upper surface to which a membrane lid 30 is sealed.

FIGS. 3 through 5 show the assembly of the metal ring 20 and membrane lid 30 in greater detail. The inner edge 26 of the metal ring is curled or rolled under to reduce the likelihood of a person cutting himself or herself on the edge when inserting a hand into the container, such as to scoop out a quantity of powdered or granular product. The metal ring 20 can comprise steel such as tin-plated steel. The steel can be either coated or uncoated.

The membrane Hd 30 comprises a disk portion 32 and a tab 34. The term "disk portion" as used herein is not limited to circular shapes, but also includes other shapes such as polygonal, elliptical, oval, and the like. The disk portion is sized larger than the aperture defined by the inner edge 26 of the metal ring such that an outer peripheral area of the disk portion overlaps the annular portion 22 of the ring. This outer peripheral area is sealed to the annular portion of the ring to initially seal the contents within the container. To access the

-3- AttyDktNo: 031599/320835 contents the first time, the membrane lid is peeled from the metal ring and discarded. A separate plastic overcap 28 (FIG. 1) is typically supplied for reclosing the container after the initial opening.

To aid in peeling off the membrane lid 30, the lid includes the tab 34, which can be grasped and pulled as shown in FIG. 2. The tab 34 is attached to the outer edge of the disk portion 32. The membrane lid as manufactured and sealed to the metal ring 20 has the tab 34 folded back onto the upper surface of the disk portion 32 so that the tab lies flat against the disk portion. This is done to keep the tab in a position that will not interfere with handling of the lid by automated sealing machinery that seals the lid to the metal ring. When a consumer desires to open the container 10, he or she lifts the tab 34 upwardly away from the upper surface of the lid and pulls the tab generally upwardly and away from the part of the metal ring nearest the tab's juncture with the outer edge of the lid, so as to peel the lid from the metal ring 20. The tab advantageously is ring-shaped, having a finger hole 36 through which a finger can be slipped to facilitate grasping and pulling the tab, as shown in FIG. 2.

In accordance with the invention, to further aid in keeping the tab in the folded-back position during automated sealing, the disk portion 32 of the membrane Hd has a localized depression 40 created by deforming the disk portion from its otherwise generally flat configuration. The depression 40 is located beneath the folded-back tab 34 and is sized in length, width, and depth to be able to receive the tab so that the tab is recessed within the depression. Advantageously, in one embodiment, the tab is recessed in the depression 40 so that the tab does not project above the upper surface of the disk portion 32 outside the depression. This substantially reduces the likelihood of the tab being inadvertently lifted from its folded-back position prior to or during automated sealing. Prematurely lifted tabs can get jammed in the automated machinery or can get torn off by the machinery, making it much more difficult for the consumer to peel off the membrane lid, or causing the metal ring and membrane Hd assembly to be rejected and have to be scrapped.

The membrane Hd comprises a permanently (i.e., plastically) deformable structure. More particularly, in preferred embodiments of the invention, the membrane lid includes a deformable layer of metal such as aluminum or the like. The deformable layer can comprise a metal foil or thin sheet metal. The metal layer in some embodiments of the invention can have a thickness of about 0.045 mm to about 0.120 mm (about 45 to 120 microns), and more

-4- AttyDktNo: 031599/320835 preferably about 0.060 to about 0.090 mm (about 60 to 90 microns). The depression 40 is formed by plastically deforming the metal layer with suitable tooling.

The membrane lid 30 includes a sealing material 38 (FIG. 2) on its lower surface for sealing the lid to the metal ring 20. The sealing material can comprise a heat-sealable material. Various heat-sealable materials are known and can be used. Non-limiting examples of suitable heat-sealable materials include heat-sealable lacquers (e.g., based on vinyl chloride, vinyl acetate, or copolymers thereof), polypropylene, polyethylene, polyamide, ethylene vinyl acetate, ethyl methacrylate, ionomer resins, epoxy resins, and blends thereof.

The membrane lid 30 can include a protective coating on the upper surface of the metal layer. The protective coating may be useful for preventing the lid from sticking to the automated sealing tooling used for heat-sealing the lid to the metal ring. For example, a polyester coating can be applied to the upper surface of the metal layer.

In one embodiment of the invention, the Hd 30 has three layers: the deformable metal layer of aluminum, a polyester coating on the upper surface of the metal layer, and a coating 38 (FIG. 2) of vinyl chloride/vinyl acetate copolymer on the lower surface of the metal layer.

The lid 30 can be manufactured from a sheet of the coated metal by die-cutting a blank from the sheet, then deforming the blank to form the depression 40, then folding the tab 34 back into the depression. The blank has the disk portion 32 and the tab 34 projecting radially outwardly from the disk portion, as a one-piece integral structure. The tab can be further processed by suitable tooling to roll the outer edge of the tab and to roll the inner edge of the finger hole 36 so as to form cut-resistant edges that are less likely to cut a consumer's finger. Once the tab is fully formed, it is folded back into the depression 40.

The lid 30 can also include embossments (schematically indicated at 42) such as dimples or a waffle pattern for stiffening the lid. The embossments are formed by suitable tooling after the blank has been die-cut from the metal sheet material. The region of the depression 40 preferably does not have embossments. Furthermore, the outer peripheral area of the lid that is sealed to the metal ring preferably does not include embossments.

-5- AttyDktNo: 031599/320835 Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

-6- AttyDktNo: 031599/320835

Claims

WHAT IS CLAIMED IS:

1. A container, comprising: a container body having a side wall that terminates in a top edge circumscribing an opening of the container body; a metal ring affixed to the top edge of the container body, the metal ring including an annular portion that extends radially inwardly from the container body and defines an upper surface, the metal ring having an inner edge circumscribing an aperture through the metal ring for access to an interior of the container body; and a membrane lid sealed to the upper surface of the metal ring, the membrane lid comprising: a permanently deformable layer having a disk portion and a tab projecting from an outer periphery of the disk portion, the tab being folded back onto an upper surface of the disk portion, a region of the disk portion underlying the folded-back tab comprising a depression formed in the disk portion and the tab being folded back into the depression such that the tab is recessed within the depression, the membrane lid further comprising a sealing material on a lower surface of the membrane lid for sealing the lid to the metal ring.

2. The container of claim 1, wherein the tab defines a finger hole therethrough.

3. The container of claim 2, wherein an outer edge of the tab and an inner edge of the finger hole are rolled to reduce the likelihood of a finger being cut by the tab.

4. The container of claim 1, wherein the deformable layer of the membrane lid comprises a sheet of metal.

5. The container of claim 4, wherein the disk portion and the tab comprise integral portions of the sheet of metal.

6. The container of claim 4, wherein the sheet of metal has a thickness of about 0.045 to 0.120 mm.

7. The container of claim 4, wherein the sealing material of the membrane Hd comprises a sealant layer joined to a lower surface of the deformable layer.

-7- AttyDktNo: 031599/320835

8. The container of claim 7, wherein the sealant layer covers substantially the entire disk portion of the deformable layer.

9. The container of claim 8, wherein the sealant layer also covers the tab.

10. The container of claim 1, wherein the sealing material comprises a heat- sealable material.

11. A membrane lid for a container, comprising: a permanently deformable layer having a disk portion and a tab projecting from an outer periphery of the disk portion, the tab being folded back onto an upper surface of the disk portion, a region of the disk portion underlying the folded-back tab comprising a depression formed in the disk portion and the tab being folded back into the depression such that the tab is recessed within the depression; and a sealing material on a lower surface of the membrane lid for sealing the lid to a container.

12. The membrane lid of claim 11, wherein the tab defines a finger hole therethrough.

13. The membrane lid of claim 12, wherein an outer edge of the tab and an inner edge of the finger hole are rolled to reduce the likelihood of a finger being cut by the tab.

14. The membrane lid of claim 11, wherein the deformable layer of the membrane lid comprises a sheet of metal.

15. The membrane lid of claim 14, wherein the disk portion and the tab comprise integral portions of the sheet of metal.

16. The membrane lid of claim 14, wherein the sheet of metal has a thickness of about 0.045 to 0.120 mm.

17. The membrane lid of claim 14, wherein the sealing material of the membrane lid comprises a sealant layer joined to a lower surface of the deformable layer.

18. The membrane lid of claim 17, wherein the sealant layer covers substantially the entire disk portion of the deformable layer.

-8- AttyDktNo: 031599/320835

19. The membrane lid of claim 18, wherein the sealant layer also covers the tab.

20. The membrane lid of claim 11, wherein the sealing material comprises a heat- sealable material.

21. The membrane lid of claim 11, further comprising a heat-resistant coating on an upper surface of the deformable layer.

22. The membrane lid of claim 11, wherein membrane lid is embossed with a pattern of deformed regions for enhancing stiffness of the lid.

23. The membrane lid of claim 22, wherein the depression is non-embossed.

-9- AttyDktNo: 031599/320835