Plastic retorable container system having a closure with an improved conformable liner

摘要

A retortable all-plastic closure having a generally circular top portion and a generally cylindrical downwardly depending skirt. The top portion has upper and lower surfaces. The lower surface of the top portion forms a circumferentially extending ridge that projects downwardly. The ridge forms a first structural wall. A second structural wall is formed in the top portion adjacent the first wall. A flexible liner made from a thermoplastic elastomer is bonded to the lower surface. The portion of the liner covering the first structural wall forms a downwardly extending liner wall. The portion of the liner covering the second structural wall forms a top liner wall. The diameter of the downwardly extending liner wall is greater than the diameter of the top of the container neck inner wall to which the closure is applied so that the container neck compresses substantially the entirety of the downwardly projecting liner wall. In addition, the diameter of top liner wall is greater than the uppermost portion of the container neck so that the top liner wall is also compressed. Grooves are formed in the closure top portion opposite the ridge so as to minimize the thickness gradient in the top portion. A network of ribs are formed in the grooves.