Patent ID: 9540155
Date: 2017-01-10
CPC Classifications: B21D,B65D,C08L

Claim:
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 C other polyolefins up to 25%.