Continental Can Company, Inc.

Continental White Cap, Inc.

Alfred W Kehe

John N Banich, Sr

Thomas T Fetters

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.

Low oxygen barrier type plastic closure with an adhered gasketing

Gaskets are formed in container closures fabricated from polyolefin resins exhibiting substantially no response to heat activation by radio frequency electrical energy by introducing a vinyl chloride plastisol containing a vinyl chloride polymer resin and a plasticizer having a loss factor in the range of 0.1-12 into the closure. The closure is preheated to 55.degree. to 100.degree. C. by conventional means and then the plastisol is fused in the closure by exposure to a field of radio frequency electrical energy.

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Berkeley, IL, United States of America

Alfred W Kehe