Pipes, based on polyamide and polyolefin, for gas transmission and/or distribution

A conduit consisting essentially of polyolefin adhered to a polyamide inner layer and a polyamide outer layer, and excluding a polyester layer, wherein one or both of the polyamide inner layer and polyamide outer layer contains a substance promoting adhesion of the polyolefin and the inner and/or outer polyamide layer, said substance being selected from the group consisting of polyethylene, polypropylene, copolymers of ethylene and at least one ∀-olefin, blends of these polymers, grafted by anhydrides of unsaturated carboxylic acid, or unsaturated epoxides;

• copolymers of ethylene with at least one substance chosen from (i) unsaturated carboxylic acids, their salts and their esters, (ii) vinyl esters of saturated carboxylic acids, (iii) unsaturated dicarboxylic acids, their salts, their esters, their monoesters and their anhydrides and (iv) unsaturated epoxides, the monomers (i) to (iv) being grafted and blends of these graphed polymers with ungrafted polymers.

A method for liquified-gas distribution or transmission in pipes, consisting essentially of transmitting liquified gas in a conduit having a polyolefin layer adhered to a polyamide inside layer, and excluding a polyester layer.

A method for gas distribution or transmission in pipes, consisting essentially of transmitting gas in a conduit having a polyolefin layer adhered to a polyamide inside layer and polyamide outside layer, and excluding a polyester layer, wherein one or both of the polyamide inside layer and polyamide outside layer contains a substance promoting adhesion of the polyolefin layer and the inside and/or outside polyamide layer, said substance being selected from the group consisting of polyethylene, polypropylene, copolymers of ethylene and at least one ∀-olefin, blends of these polymers, grafted by anhydrides of unsaturated carboxylic acid, or unsaturated epoxides;

• copolymers of ethylene with at least one substance chosen from (i) unsaturated carboxylic acids, their salts and their esters, (ii) vinyl esters of saturated carboxylic acids, (iii) unsaturated dicarboxylic acids, their salts, their esters, their monoesters and their anhydrides and (iv) unsaturated epoxides, the monomers (i) to (iv) being grafted and blends of these graphed polymers with ungrafted polymers.

A conduit comprising three layers including a polyamide outer layer, a polyolefin inner layer and a tie-layer between, wherein said conduit requires a reeling force of less than or equal to 425 N to impose a radius of curvature of 535 nm, further wherein the polyamide layer contains a substance promoting adhesion of the polyamide and polyolefin layers, said substance being selected from the group consisting of polyethylene, polypropylene, copolymers of ethylene and at least one ∀-olefin, blends of these polymers, grafted by anhydrides of unsaturated carboxylic acid, or unsaturated epoxides;

• copolymers of ethylene with at least one substance chosen from (i) unsaturated carboxylic acids, their salts and their esters, (ii) vinyl esters of saturated carboxylic acids, anhydrides and (iv) unsaturated epoxides, the monomers (i) to (iv) being grafted and (iii) unsaturated dicarboxylic acids, their salts, their esters, their monoesters and their anhydrides and (iv) unsaturated epoxides, the monomers (i) to (iv) being grafted and blends of these graphed polymers with ungrafted polymers.