Coextrusion binder, its use for a multilayer structure and the structure thus obtained

A multilayer structure comprising a layer comprising a coextrusion binder produced by a process comprising blending:

• 5 to 30 parts by weight of a polymer (A) comprising cografting a blend of a polyethylene (A1) of relative density between 0.935 and 0.980 and of a polymer (A2) of a metallocene polyethylene with 600 ppm−6% by weight of an unsaturated carboxylic acid or its functional derivative with respect to the weight of grafted (A1) and (A2);
• and
• 95 to 70 parts by weight of a polyethylene (B) of relative density between 0.930 and 0.950;
• the polyethylene (B) having:
• a relative density between 0.930 and 0.950,
• a content of grafted unsaturated carboxylic acid of between 30 and 10,000 ppm, and
• melt flow index measured according to ASTM D 1238 at 190° C./2.16 kg of between 5 and 100;
• directly attached to said binder, a layer (E) selected from the group consisting of a layer of a nitrogen-containing or oxygen-containing polar resin, a layer of polyamide resin, a layer of an aliphatic polyketone, a layer of a saponified ethylene-vinyl acetate copolymer (EVOH), a layer of polyester resin, and a metal layer.

A multilayer structure comprising a layer comprising a coextrusion binder consisting essentially of:

• 5 to 30 parts of a polymer (A) comprising a blend of a polyethylene (A1) of relative density between 0.935 and 0.980 and of a polymer (A2) a metallocene polyethylene with 600 ppm−6% by weight of an unsaturated carboxylic acid or its functional derivative with respect to the weight of cografted (A1) and (A2);
• and
• 95 to 70 parts of a polyethylene (B) of relative density between 0.930 and 0.950;
• the blend of the polymer (A) and the polyethylene (B) having:
• a relative density between 0.930 and 0.950,
• a content of grafted unsaturated carboxylic acid of between 30 and 10,000 ppm, and
• a melt flow index measured according to ASTM D 1238 at 190° C./21.6 kg of between 5 and 100;
• directly attached to said binder, a layer (E) selected from the group consisting of a layer of a nitrogen-containing or oxygen-containing polar resin, a layer of polyamide resin, a layer of an aliphatic polyketone, a layer of a saponified ethylene-vinyl acetate copolymer (EVOH), a layer of a polyester resin, and a metal layer.