Closure for retortable plastic container

Claim 1

An improved package comprising the combination of a composite closure (1; 60; 80; 90; 100) and a container (3; 21; 39; 50; 62; 93; 106) having a rim (17; 34; 65; 92) with an outwardly and upwardly tapered annular inner sealing surface and an inwardly and upwardly tapered annular outer surface, said composite closure having a disc (2; 30; 63) having a radially outer annular portion with a first surface which extends upwardly and outwardly forming a tapered annular sealing surface for cooperation with the outwardly and upwardly tapered annular inner sealing surface of the rim (17; 34; 65; 92) of the container (3; 21; 39; 50; 62; 93; 106) and a second surface extending downwardly and outwardly forming a tapered annular outer sealing surface with the outwardly and downwardly tapered outer surface of said rim, and said disc (2; 30; 63) configured such that said outer annular portion tightly engages the tapered annular sealing surface of said rim (17; 34; 65; 92); sealant material (8; 31; 68; 98; 102) disposed on said outer annular portion of said disc (2; 30; 63) for sealing engagement with the container rim (17; 34; 65; 92); and a moulded plastic ring (4; 35; 52; 61; 83) including a skirt (9) with container-engaging means (11; 25; 37; 51; 82; 94) and a top portion (10) having a downwardly opening C-shaped radial cross section, said cross section having a downwardly extending inner annular leg segment which is substantially parallel to the center axis of said ring (4; 35; 52; 61; 83) and an outer segment which is also substantially parallel to the center axis of said ring, wherein said inner annular leg segment engages and retains said tapered annular inner sealing surface of said disc (2; 30; 63) with said sealant material (8; 31; 68; 98; 102) thereon in sealing engagement with the tapered annular inner sealing surface of said rim (17; 34; 65; 92) and wherein said outer segment engages and retains said tapered annular outer surface of said disc, with said sealant material thereon in sealing engagement with the tapered annular outer sealing surface of said rim, such that said inner and outer leg segments of said ring (4; 35; 52; 61; 83) exert a clamping action on said tapered annular first and second sealing surfaces of said disc (2; 30; 63) to maintain a continuous seal and to cause the seal to be relatively insensitive to vertical movement of the closure.