Closure Liner Composition With Improved Oxygen Reduction

Abstract

Disclosed is a closure liner composition comprising a mixture (or blend) of a thermoplastic polymer, an oxygen barrier polymer, and a particulate oxygen scavenging material. The oxygen barrier polymer preferably comprises polyisobutylene. The particulate oxygen scavenging material preferably is selected from the group consisting of an alkali metal salt of sulfite, ascorbate, isoascorbate, and a mixture of two or more of these materials. The closure liner composition may be used to fabricate a liner for a closure (e.g., a metal crown used to cap a bottle) that provides superior oxygen reduction properties and improved shelf life.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to a closure liner composition with improved oxygen reduction.[0002]Closures (or caps) for use in food, beverage and pharmaceutical containers are typically made of plastic or metal or both metal and plastic. Such closures generally include a liner (or gasket) on the inner surface to provide a hermetic seal at the container opening. Since many products that are packaged in a container can be adversely affected by the presence of oxygen, it is particularly desirable if the closure liner is formulated to prevent oxygen ingress. Various products are oxygen sensitive and must be protected from oxygen ingress, the most typical one being beer. Such oxygen sensitive products, particularly beer, are typically packaged in a bottle capped with a metal closure (or crown).[0003]Various techniques have been employed to formulate liner compositions to prevent oxygen ingress. In one technique, as described, for example, in U.S. Pat. No...

AI Technical Summary

Benefits of technology

The present invention offers a closure liner made of a blend of thermoplastic polymer, oxygen barrier polymer, and particulate oxygen scavenging material. The oxygen barrier polymer is preferably polyisobutylene, while the oxygen scavenging material may be one or more of alkali metal salts of sulfite, ascorbate, isoascorbate, or a mixture of these. This composite provides excellent oxygen reduction and improved shelf life.

Problems solved by technology

With this type of closure liner, the oxygen scavenger will reduce the amount of residual oxygen in the headspace of the container upon filling, as well as consume any external oxygen that permeates through the closure.

A multilayer device such as this is expensive and complicated to manufacture because it requires multiple different manufacturing process steps: e.g., a multilayer liner sheet is coextruded, then formed into individual liners and then placed into the cap.

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