Abstract: A method for molding thermoformable synthetic plastic sheet material into a circular lid having a downturned rim with a bead on its inner face. The sheet material is softened by heating and disposed between male and female dies which are moved together to fold the sheet material over the male die to form the downturned rim. The material forming the rim is compressed and sheared between the dies to force material into a bead cavity in the male die to form the bead. The molded lid can fit over the top edge of a container with the bead in sealing engagement with the container.

Abstract: A thin-walled nestable plastic container of the type having a tapering cylindrical wall is provided with an expansible bottom employing a central conical portion projecting upwardly into the container. The central conical portion is arranged to invert under pressure so that the cone decreases in height as it turns inside out. The base of the cone remains circular as the cone inverts and thereby provides a stable base on which the container can rest. The cone is not intended to invert completely and consequently, the apex of the cone is preferably stiffened by thickening of the wall.