Multilayer tubular structure having better resistance to extraction in biofuel and use thereof

A multilayer tubular structure (MLT) suitable for the transport of fuels, wherein the MLT comprises, from an outer surface of the MLT inward:

• a first outer layer comprising from 0 to 15% by weight of a plasticizer relative to the total weight of the composition of the outer layer, the first outer layer comprising a polyamide selected from the group consisting of PA11, PA12, PA610, PA612, PA1012, the corresponding copolyamides thereof, and mixtures thereof;
• a second binder layer having a thickness of at most 15% of the total thickness of the MLT, the second binder layer comprising a polyamide mixture selected from the group consisting of the binary mixtures:
• PA6 and PA12, PA6 and PA612, PA6 and PA610, PA12 and PA612, PA12 and PA610, PA1010 and PA612, PA1010 and PA610, PA1012 and PA612, and PA1012 and PA610;
• a barrier layer comprising EVOH and an impact modifier;
• a first binder layer having a thickness of at most 15% of the total thickness of the MLT, the first binder layer comprising a polyamide mixture selected from the group consisting of the binary mixtures:
• PA6 and PA12, PA6 and PA612, PA6 and PA610, PA12 and PA612, PA12 and PA610, PA1010 and PA612, PA1010 and PA610, PA1012 and PA612, and PA1012 and PA610;
• and
• an inner layer comprising at least one aliphatic polyamide, wherein the at least one aliphatic polyamide is selected from the group consisting of PA610, PA612, the corresponding copolyamides thereof, and mixtures thereof, and
• wherein the inner layer, first binder layer, and all layers located inward of the barrier layer do not contain plasticizer, and
• wherein the MLT exhibits an extractables value of less than or equal to 6 g/m2 of tube inner surface area after being filled with an alcohol-containing petrol FAM B and heated at 60° C. for 96 hours,
• said extractables value determined after heating by emptying and filtering the alcohol-containing petrol into a beaker to obtain a filtrate, evaporating the filtrate at room temperature to obtain a residue of the filtrate, and weighing the residue of the filtrate.