Tabbed container seal and method of manufacture

Abstract

An improved container seal including at least one metal-free tab member is provided. The container seal comprises a flexible, metal-free cover sheet and a flexible sealant sheet. The cover sheet comprises at least one layer of a flexible sheet material and includes a body portion that is sized and shaped to at least cover a container finish and has at least one metal-free tab portion extending from the periphery of the body portion. The flexible sealant sheet comprises a thermoplastic sealing surface layer, an inner surface layer and a layer of metal foil. The flexible sealant sheet is of the same size and shape as the body portion of the cover sheet. The inner surface of the sealant sheet and the inner surface of the body portion of the cover sheet are bonded together in opposed, congruent contact with each other. A method of manufacturing the container seal is also provided.

Description

FIELD OF THE INVENTION[0001]The invention relates to improved container sealing materials and methods of manufacture thereof. More particularly, the invention relates to improved container seals having a tab portion, and methods of manufacturing the tabbed container seals.BACKGROUND OF THE INVENTION[0002]It is common practice to seal a container with a sheet material, such as paper, a polymeric film, aluminum foil, or a laminate of paper, polymeric film and / or aluminum foil. The use of such seals, in many cases, has been imposed on the packaging industry by FDA regulations, as a protection against product tampering. Such seals can provide evidence of product tampering, since they are typically destroyed by the process of removing the seal. It is also common to line the inner surface of container closures with a moderately compressible material, such as a polymeric material, pulp board, or a multilayer laminated combination thereof. When a closure containing the liner material is sec...

AI Technical Summary

Benefits of technology

[0013]In use, a tabbed container seal of the invention is sealed over the access opening of a container by thermally sealing (i.e., by conduction or induction) the sealing surface layer of the sealant sheet onto the container finish (i.e., onto the rim surrounding the access opening) to seal the opening. The tab member, being metal-free, does not interfere with the thermal sealing process and does not adhere to any portion of the container finish or to the top of the seal after the container seal has been bonded to the container finish. The tab portion is freely accessible so that a consumer can readily grasp the tab and pull the seal off of the container opening to access the contents of the container. The container seals of the present invention provide a seal that is simple to manufacture, and which provides a more reliable and consistent seal than conventional tabbed induction seals.

Problems solved by technology

Such seals can provide evidence of product tampering, since they are typically destroyed by the process of removing the seal.

During the induction sealing process the tab can become sealed to the threaded side of the container finish, which is generally undesirable.

In this arrangement, the tab can become sealed to the closure, which is also undesirable.

In addition, the shape of the tab can adversely influence the induction sealing of the seal to a container finish.

The variability in bonding strength of the seal around the container finish can lead to leakage problems at the weaker point near the tab.

The folded portion of the seal is considerably thicker than the remainder of the seal, leading to uneven pressure on the seal at the container finish (i.e., higher pressure at the folds and lower pressure at the unfolded portions).

This can lead to uneven bonding and possible seal failure.

Folded tab structures are complicated to manufacture and have not been readily accepted in the marketplace.

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