Patent ID: 6087001
Filing Date: 2000-07-11
Classification: B32B,C08F,C09J,Y10T

Abstract:
Multilayer structure including a first layer and a coextrusion binder, said coextrusion binder comprising:a mixture of at least one polymer (A) comprising at least 75 mol % of ethylene and which has an MI.sub.2 /(.eta.).sup.-8.77 ratio with an absolute value greater than 15, and at least one polymer (B) different from (A) selected from the group consisting of polymers having at least 50 mol % of ethylene and block copolymers of styrene;wherein (B) has an MI.sub.2 /(.eta.).sup.-8.77 ratio with an absolute value of greater than 15; and wherein .eta. denotes the viscosity index (dl/g) of the respective polymer measured in a decalin solution at 135.degree. C.;the mixture of (A) and (B) being grafted with an unsaturated carboxylic acid or a compound of this acid;the cografted mixture of (A) and (B) optionally being diluted in a polymer (C) selected from the group consisting of homo- or copolymers of ethylene and block copolymers of styrene;the binder further having:(a) an ethylene content which is not less than 70 mol %;(b) a carboxylic acid content or a content of the compound of this acid of 0.01 to 10 weight % with respect to the weight of the binder, and(c) a MI.sub.10 /MI.sub.2 ratio of 5 to 20, where MI.sub.2 is the melt flow index at 190.degree. C. under a load of 2.16 kg, measured according to ASTM D1238, and MI.sub.10 is the melt flow index at 190.degree. C. under a load of 10 kg, measured according to ASTM D1238; anddirectly attached to said first layer, a layer (E) of nitrogen-containing or of oxygen-containing polar resin, of a saponified copolymer of ethylene and of vinyl acetate or of a polyester resin, or said layer (E) being a metal layer,wherein said structure comprises a layer of high density polyethylene, a layer of the binder and a layer of polyamide or of alloy of polyolefin and of polyamide.