Lidstock material having improved sealability and peelability to wide classes of materials

Abstract

A material that can be used as a lid (12) on a container (14, 40), the lid containing a solid substrate (30) and a peelable and heat sealable film (32) which contains a mixture of at least aliphatic-aromatic copolyester, inorganic filler, butene-1 polymer and ethylene-vinyl acetate copolymer, where the substrate (30) is preferably made of aluminum.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a lidstock material suitable for making lids to be sealed over plastic containers such as pharmaceutical blisters. BACKGROUND OF THE INVENTION [0002] Many products are placed in containers covered by a lidstock material and such products can range from yogurt to disposable contact lenses. Such lidstocks must be sealable to a very wide class of materials, peelable and resistant to both hot and cold temperatures. [0003] Many pharmaceuticals and disposable contact lenses are packaged in blister packages consisting of 2 pieces: a base and a lid. The base is an injection molded plastic shaped to include a bowl-shaped or rectangular recess for receiving the contents. In the case of contact lenses, each blister pack generally contains a contact lens and enough solution to prevent drying and to maintain the contact lens ready for use. [0004] The lid covering the base is heat sealed over the recess containing the contents of the ...

AI Technical Summary

Benefits of technology

[0016] The substrate is preferably coated with a print primer. The print primer facilitates application of printed labeling on the substrate. A particularly preferred print primer has a coating weight of about 0.4 to 0.9 pound per 3000 square feet (0.6-1.4 g./sq meter).

[0017] The peelable and heat sealable film has a total weight of about 17 lb per 3000 square feet (27 g/sq meter). The filler enhances peelablity of the coating by assisting the seal failure upon peeling from adhesive failure at the container-coating layer interface to cohesive failure in the coating layer itself. The filler preferably is selected from at least one of talc, silica or alumina and comprises at least about 15 wt. % of the coating, preferably about 15 wt. % to 30 wt. %, more preferably about 20 wt. % to 30 wt. %. The filler is preferably a

Problems solved by technology

Packaging Digest describes a lidstock containing a type ethylene acid copolymer which replaces adhesive-mounted versions having high peel strengths making them somewhat difficult to wpen with an extrusion mounted version.

The prior art lidstock materials generally suffer from one or more serious disadvantages making them less than entirely su

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