Abstract: A plastic closure formed from polymeric materials in accordance with the present invention is configured for enhanced performance, including enhanced strength and impact resistance. In one aspect of the present invention, the closure includes a top wall portion, and an annular, depending skirt portion which defines a plurality of circumferentially spaced, axial columns. Notably, in accordance with the illustrated embodiment, each of these axial columns is provided by a group of gripping knurls provided on the exterior of the skirt portion, with each group of the gripping knurls having relatively shallow valleys between adjacent ones of the knurls.

Abstract: A composite closure having a double-wall configuration facilitates convenient use by consumers, and permits in-shell formation of a sealing liner. The closure includes an outer closure cap having inner and outer annular skirt portions arranged in concentric relationship with each other. The closure includes a sealing liner formed in the closure cap at the inside surface of the top wall portion of the closure cap. A method of compression-molding the sealing liner is disclosed.

Abstract: A plastic closure embodying the principles of the present invention comprises a closure cap having a top wall portion, and an annular skirt portion depending from the top wall portion. The skirt portion includes an internal thread formation for threaded engagement with the external thread formation of an associated container. In order to facilitate high-speed application, and minimize the use of polymeric material, the closure is configured to exhibit a variation in retention force which decreases in a direction away from the top wall portion of the closure cap.