Importance

Loading Importance Indicators...

Abstract

A container closure formed from a thermoplastic polyolefin, e.g. polypropylene, which has been molded and adheres simultaneously to a coated foil, e.g. an aluminum insert, to which a conventional plastisol gasketing compound may be adhered to provide a hermetic container seal under hot fill and retort conditions. In order to facilitate adhesion to both the polypropylene closure panel and the PVC plastisol gasketing compound, a dead soft aluminum foil web was first coated on one side with an organosol utilizing a gravure coater, after which the coated web was passed through an oven. The partially coated web was then coated with a primer dispersion again utilizing a gravure coater, after which the coated web was passed through a second oven. A layer of polypropylene homopolymer was applied to the primer and inserts were die cut from the resultant web. The inserts were incorporated in a closure injection molding apparatus and a plastic closure injection molded thereabout. Thereafter a plastisol gasket compound was applied to the exposed surface of the insert and fused by convection and/or induction or dielectric heat.

Loading the Abstract Image...

First Claim