Plastic closure cap with early venting inner seal

摘要

The invention relates to a screw-closure cap made of plastic material, which has a neck-like inner seal (4) for sealing off the container to be closed. The inner seal consists of a narrow seal part (5) and an insertion part (6) which adjoins the latter below it and which is provided for centring and for the careful introduction of the inner seal. In order to achieve the fact that the container is vented as early as possible when unscrewing the closure cap, venting cutouts (9) are provided on the insertion zone (6) of the inner seal. These prevent the sealing-off of the container by the insertion part and allow gas to flow out of the container as soon as the sealing part becomes disengaged from the container mouth. The side faces of the venting cutout serve at the same time as friction faces in order to smooth any unevenness in the container mouth before the actual sealing part comes into engagement.