Sealing caps for polyethylene bottles - prepd. by heat treating cap formed from aluminium-polyethylene laminate above softening temp. of polyethylene

摘要

Caps having a flat closed upper side and a cylindrical, downwardly directed cover, for closing polyethylene bottles, are produced by (a) forming the cap by stamping and pressing a flat sheet or strip consisting of an Al-polyethylene laminate, and (b) subjecting the capsules, before connecting to the bottle, to heat treatment at or above the softening temp. of the polyethylene layer of the laminate. The closed bottles can be sterilised at 110-120 degrees C without loss of the bond between the layers of the laminate. Decay of perishable contents e.g, milk, through loss of the seal is thus prevented.