Improvement in or relating to apparatus for forming a seal on a closure and to a closure having a seal formed from a foamed adhesive material.

摘要

Improvements in or relating to apparatus for forming a seal on a closure and to a closure having a seal formed from foamed adhesive material. Such an apparatus comprises means (12) for dispensing thermoplastic adhesive material onto the closure (14) as a foamed layer, means (13) for maintaining the foamed layer as a foam to form a seal (40) and means (19) for mixing the adhesive material with a gas to form a mixture which on dispensing evolves gas to form the foam. Such a closure (14) has a seal (40) formed from an adhesive foam, the foam being obtained by mixing thermoplastic adhesive material with a gas and dispensing the mixture onto the interior surface (37) of the closure (14) the mixture evolving gas to form the adhesive foam. The seal (40) formed has greater resilience and requires less material than a seal made of the same material in an unfoamed condition. The sealing material on the closure also requires no heating in order to be cured.