Abstract: A method of compression molding a plastic article, such as a closure, includes providing a molten polymeric material, comprising a mixture of at least one molten polymer and a gas blended therein. The polymeric material is molded between cooperating male and female molds, with relative movement of the molds controlled to form a mold cavity with a predetermined volume. Formation in this manner acts to produce a molded closure with substantially reduced density, thus achieving desired material savings, while still providing a closure or like article exhibiting desired performance characteristics.

Abstract: An apparatus for molding a plastic closure includes a male mold assembly including a forming pin and an outer pin sleeve which cooperate with a female mold for defining a mold cavity. To facilitate mechanical stripping of a molded closure from the forming pin, pressurized air is introduced into the molded closure through at least one air passageway which extends axially between the forming pin and pin sleeve. By outwardly expanding and forming the plastic closure during ejection from the forming pin, forces to which the closure is subjected during ejection are significantly reduced, thereby desirably reducing the amount of cooling of the closure that is required during the molding cycle prior to ejection. Significantly increased operating speeds for the compression molding apparatus can thus be achieved.

Abstract: An apparatus for molding a plastic closure includes a male mold assembly including a forming pin and an outer pin sleeve which cooperate with a female mold for defining a mold cavity. To facilitate mechanical stripping of a molded closure from the forming pin, pressurized air is introduced into the molded closure through at least one air passageway which extends axially between the forming pin and pin sleeve. By outwardly expanding and forming the plastic closure during ejection from the forming pin, forces to which the closure is subjected during ejection are significantly reduced, thereby desirably reducing the amount of cooling of the closure that is required during the molding cycle prior to ejection. Significantly increased operating speeds for the compression molding apparatus can thus be achieved.

Abstract: An apparatus for molding a plastic closure includes a male mold assembly including a forming pin and an outer pin sleeve which cooperate with a female mold for defining a mold cavity. To facilitate mechanical stripping of a molded closure from the forming pin, pressurized air is introduced into the molded closure through at least one air passageway which extends axially between the forming pin and pin sleeve. By outwardly expanding and forming the plastic closure during ejection from the forming pin, forces to which the closure is subjected during ejection are significantly reduced, thereby desirably reducing the amount of cooling of the closure that is required during the molding cycle prior to ejection. Significantly increased operating speeds for the compression molding apparatus can thus be achieved.

Abstract: An apparatus for molding a plastic closure includes a male mold assembly including a forming pin and an outer pin sleeve which cooperate with a female mold for defining a mold cavity. To facilitate mechanical stripping of a molded closure from the forming pin, pressurized air is introduced into the molded closure through at least one air passageway which extends axially between the forming pin and pin sleeve. By outwardly expanding and forming the plastic closure during ejection from the forming pin, forces to which the closure is subjected during ejection are significantly reduced, thereby desirably reducing the amount of cooling of the closure that is required during the molding cycle prior to ejection. Significantly increased operating speeds for the compression molding apparatus can thus be achieved.