| 摘要 |
A closure for a container with a neck portion and an external helical thread formed on the neck portion includes an upper wall and a skirt formed integrally with and extending generally downwardly from the upper wall. An internal helical thread is formed on the skirt for engaging the external helical thread of the neck portion to thereby secure the closure to the container. The internal helical thread is preferably asymmetrical in cross section. A first annular seal extends generally radially inwardly toward a central axis of the closure from the inner skirt surface. The first annular seal sealingly engages the outer surface of the neck portion. A second annular seal extends generally axially downwardly from the upper wall and sealingly engage an inner surface of the neck portion. A thickness of the neck portion between the first and second annular seals is greater than the distance between the first and second annular seals before installation of the closure on the container. When the closure is installed on the container, the first and second annular seals are biased toward each other and against the outer and inner surfaces, respectively. A third annular seal is provided on a lower surface of the upper wall between the first and second annular seals for engaging an upper edge of the container neck portion. A tamper-evident security ring is frangibly connected to the skirt and includes a plurality of tabs that prevent removal of the security ring from the container.
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