Multilayer structure possessing a better resistance to the extraction in the bio - gasoline and its use

摘要

The present invention relates to a multilayer structure (mlt) intended for the transport of fluids, in particular of gasoline, in particular alcohol comprising from the outside towards the inside at least a barrier layer (1) and at least one inner layer (2) located at the - bottom of the barrier layer, said inner layer (2) or the set of layers (2) and the other layers located below the - if any of the barrier layer, containing on average from 0 to 1,5% by weight of plasticizer relative to the total weight of the composition of the layer (2) or to the total weight of the assembly of the compositions of the layers (2) and the other layers located below the - if any of the barrier layer, said inner layer (2) mainly comprising at least one aliphatic polyamide type or made up of more than 75% of aliphatic units, said aliphatic polyamide being selected from among: - a polyamide marked with a mean number of carbon atoms per atom of nitrogen referenced ca ranging from 4 to 8,5, advantageously from 4 to 7; - a polyamide, designated b and a mean number of carbon atoms per atom of nitrogen (cb in the range of 7 to 10, advantageously to 7,5 to 9,5; - a polyamide, denoted c having a mean number of carbon atoms by nitrogen atom to be noted that in the range of 9 to 18, advantageously from 10 to 18, provided that, when said inner layer (2) comprises at least three polyamides, at least one of the polyamides a, b or c is excluded.