Plastic closure with compression molded layered barrier liner

Abstract

A plastic closure includes a closure shell having a base wall, a peripheral skirt with an internal thread for securing the closure to a container finish, and an annular lip extending from the closure skirt adjacent to the base wall and defining an inside lip surface at an acute angle to the closure base wall. A liner is compression molded in situ onto the base wall and peripherally within the lip. The liner has a liner base portion extending along the base wall and a peripheral portion extending along the inside surface of the lip. The liner has an interior surface—i.e., facing away from the shell base wall and skirt—that has a first flat axially facing portion on the base portion of the liner adjacent to the peripheral portion, an inwardly concave portion where the base portion blends into the peripheral portion of the liner, a second flat axially facing portion at an edge of the peripheral portion of the liner, and a conical portion that extends from a radially outer edge of the second flat portion to the inside surface of the lip. Provision of the second flat axially facing surface portion at the periphery of the liner has been found to reduce tearing of the liner and separation of layers in the liner when the liner is of layered construction.

Dependencies are inferred from the claim text.