Abstract: A plastic closure is disclosed which has an integral sealing means formed by an annular resiliently deflectable V-shaped wall section with a downwardly and outwardly projecting corner on it for sealing against an upwardly facing sealing surface on a container. The closure also has a stop member projecting downwardly and inwardly from near the top of the closure skirt for engagement against the container mouth during application of the closure on a container to arrest the axial travel of the closure on the container. The closure may have paraffin or wax lubricant either in the plastic material of the closure or on the inside surface to reduce the torque required to seal the closure on a container.

Abstract: A linerless plastic closure is disclosed which is adapted to seal containers for pressurized contents such as carbonated beverages and which utilizes a plug configuration that is designed to expand under pressure. This is accomplished by making the plug in the form of a disc spring washer with tubular supports joining it to the top of the closure. Pressure against the disc spring washer increases the pressure of the seal against the interior surface of the bottle mouth to provide a reliable seal. The closure may have a slot through the threads on the closure to permit rapid escape of gases from the container during removal of the closure from the container. In this way, dangerous blow-off of the closure from a container is substantially eliminated.