Polymer compound for seals for use with fat-containing filling materials

摘要

The invention relates to a polymer compound for a sealing insert for a container closure, in particular for fat-containing filling materials, which has a composition such that the migration of constituents of the compound into the filling material is reduced, characterized in that the Shore A hardness of the polymer compound is between 45 and 95 and in the compressive deformation test analogous to ASTM D395-97 Method B at 70 DEG C the polymer compound exhibits a compression set of 30-90%.

主权项

1. A method for producing press on and twist off caps for containers having an opening with an inner diameter above 2 cm that is to be closed by the container closure comprising a polymer-based sealing element which is arranged in the container closure in such a manner that it sealingly contacts the opening of the container in the closed state, in which method a polymer compound is made sufficiently flowable by heating and applied to the container closure in the region of the sealing element to be produced and brought mechanically into the desired shape which is maintained after it has cooled,
wherein the Shore A hardness of the polymer compound is in the range of 40 to 90 and the polymer compound shows a compression set between 30% and 70% in the compressive deformation test according to ASTM after 22 hours at 70° C. and a compression of 25%, the polymer compound is PVC-free and wherein the polymer compound comprises a block copolymer which on the one hand comprises polyethylene units and on the other hand is built up from an alkene monomer, selected from the group consisting of propene, butene, hexene and octene, in the range of 20% to less than 100%; a random copolymer, that is composed of a linear or branched interpolymer of ethylene on the one hand and at least one C3-C20 alpha-olefin on the other hand, in the range of less than 80%; and other polyolefins up to 25%.