Composite closure for polypropylene containers - comprises pref. aluminium foil coated with grafted polyolefin(s) mixt.

摘要

The parent patent described a composite material used as closure for a container and comprising a metal foil and an adhesive layer. In this addn. the container is specifically made of polypropylene and the adhesive comprises a mixt. of (A) a copolymer of ethylene and a monoethylenically unsatd. carboxylic acid, and (B) a propylene polymer grafted with a monoethylenically unsatd. carboxylic acid, pref. acrylic acid. Further, thermosealing of the composite closure to the container is effected at 170-250 deg.C. Specifically for sealing dessert cream or yoghurt tubs, the sealing being effected at 40-100 deg.C. immediately after filling the container. The closure can be easily peeled off for opening the container.