Use of multi-layered structure for the manufacture of gas conducts, namely for methane

A process for transporting natural gas, consisting of transporting said natural gas in a multilayer gas duct structure consisting of, from the outside towards the inside, the following successive layers:

• a layer 1 comprising at least one polyamide, that is PA-11, PA-12 or an aliphatic polyamide resulting from the condensation of an aliphatic diamine having from 6 to 18 carbon atoms and an aliphatic diacid having from 9 to 18 carbon atoms;
• optionally, in contact with layer 1 a tie layer 2;
• and
• a layer 3, in contact with layer 1 or, if present, layer 2, which layer 3 is an EVOH layer, a layer formed from a blend of polyamide and a polyolefin with a polyamide matrix, a PA-6, PA-6,6, MXD-6 or MXD-10 layer or a semi-aromatic copolyamide layer, the layer 3 being in contact with the transported natural gas.

A process for transporting natural gas, comprising transporting said natural gas in a multilayer gas duct structure comprising, from the outside towards the inside, the following successive layers:

• a layer 1 comprising at least one polyamide, that is PA-11, PA-12 or an aliphatic polyamide resulting from the condensation of an aliphatic diamine having from 6 to 18 carbon atoms and an aliphatic diacid having from 9 to 18 carbon atoms;
• in contact with layer 1 a tie layer 2;
• and
• a layer 3, in contact with layer 2, which layer 3 is an EVOH layer, a layer formed from a blend of polyamide and a polyolefin with a polyamide matrix, a PA-6, PA-6,6, MXD-6 or MXD-10 layer or a semi-aromatic copolyamide layer,
• the layer 3 being in contact with the transported natural gas.

A process for transporting natural gas, comprising transporting said natural gas in a multilayer gas duct structure comprising, from the outside towards the inside, the following successive layers:

• a layer 1 comprising at least one polyamide, that is PA-11, PA-12 or an aliphatic polyamide resulting from the condensation of an aliphatic diamine having from 6 to 18 carbon atoms and an aliphatic diacid having from 9 to 18 carbon atoms;
• optionally, in contact with layer 1 a tie layer 2;
• and
• a layer 3, in contact with layer 1 or, if present, layer 2, which layer 3 is an EVOH layer, a layer formed from a blend of polyamide and a polyolefin with a polyamide matrix, a PA-6,6, MXD-6 or MXD-10 layer or a semi-aromatic copolyamide layer,
• the layer 3 being in contact with the transported natural gas.