Coextrusion tie based on cografted metallacene polyethylene and LLDPE on SBS and on PE

摘要

The present invention relates to a coextrusion tie comprising 10 to 35 weight % of a polymer (A) itself composed of a blend of 80 to 20 weight % of a metallocene polyethylene (A1) with a density of between 0.865 and 0.915 and of 20 to 80 weight % of a non-metallocene LLDPE polyethylene (A2), the blend of polymers (A1) and (A2) being cografted by an unsaturated carboxylic acid or its derivative, the content of which in the said blend is between 30 and 100 000 ppm; 40 to 60 weight % of a styrene/butadiene/styrene block copolymer (B) with 50 to 90 mol % of styrene; and 20 to 35 weight % of PE (C); the total making 100%, the blend of (A), (B) and (C) being such that the MFI or melt flow index (ASTM D 1238, 190° C., 2.16 kg) is between 0.1 and 10 g/10 min. The present invention also relates to a multilayer structure comprising a layer of tie according to the invention and to the objects comprising such a structure.