Multilayer combining both good ageing properties and resistance to bursting in hot conditions, that can be used for high-temperature motor vehicle applications

Abstract

The present invention concerns a multilayer tubular structure (MLT) intended for transporting fluids such as air, oil, water, a urea solution, a cooling liquid made from glycol, a transmission oil cooler (TOC), or an air conditioning liquid, or a fuel such as petrol, in particular bio-petrol, or diesel, in particular bio-diesel, comprising at least one layer (1) and at least one layer (2), said layer (1) comprising a composition comprising: -a) at least 50% by weight of at least one semi-aromatic polyamide of formula W/ZT, -b) at least 10% by weight, preferably at least 15%, of an impact modifier, -c) between 0 and 20% by weight of at least once plasticiser, -d) between 0 and 40% by weight of at least one additive, the sum of a) +b) +c) +d) being equal to 100%, said layer (2) comprising a composition comprising a') at least 50% by weight of at least one short-chain semi-crystalline polyamide referred to as (A), said short-chain aliphatic polyamide (A) being of formula X Y/Z, or formula V/Z, -b′) between 0 and 15% of at least one impact modifier, -c′) between 0 and 12% by weight of at least once plasticiser, -d′) between 0 and 40% by weight of at least one additive, the sum a′)+b′)+c′)+d′) being equal to 100%.