| 摘要 |
A thermoplastic closure (10) for fitment to a container for packaging a product capable of producing internal container pressure, e.g., a carbonated beverage, is disclosed. The closure (10) comprises a top wall (12) and an annular sidewall (14). An closure thread (20) is provided on the inside surface of the sidewall (14) and is preferably extended to require the user to make two turning motions to achieve removal. Thread (20) cooperates with the container neck thread (42) to achieve fitment of the closure (10) to the container neck (40). A sealing system (22) adjacent the top wall of the closure provides sealing of the closure to the container. Gas venting structure (26) is provided on the closure for venting of pressurized gas from the container upon loss of the seal when the closure is rotated to remove it from the container. Stand-off protuberances (32) are provided about the lower inside surface (28) of sidewall (14). A heat-shrinkable tamper-indicating means (16) is attached to the lowermost edge of the sidewall of the closure (10). Application of heat to the tamper-indicating means (16) causes it to shrink towards the container and to a point of interference with a container flange (48). The combination of tamper-indication means (16), venting structure (26) and protuberances (32) enables a closure to be formed with tamperproof properties and compatible resistance to premature release from a pressurized container. |
