Patent ID: 7960014

Claim:
A multilayer structure comprising at least one couple (L1-L2) of adjacent layers (L1) and (L2), wherein layer (L1) comprises at least one polymer composition (C1) comprising a grafted fluoropolymer material (M1) consisting of N 1 grafted fluoropolymer(s) (P1), said polymer(s) (P1) being obtained by a process comprising grafting onto an ungrafted fluoropolymer (U1) at least one grafting agent (G1) chosen from ethylenically unsaturated carboxy acids, their esters, their anhydrides and their salts, layer (L2) comprises at least one polymer composition (C2) comprising at least one impact modifier (I2) and a semi-crystalline aromatic polyamide material (M2) consisting of N 2 semi-crystalline aromatic polyamide polymer(s) (P2), and the average melting temperature (T av,1 ) of material (M1) differs by at most 35° C. from the average melting temperature (T av,2 ) of material (M2), N j being the number of polymer(s) (Pj) of material (Mj), Nj≧1, T av,j being equal to ( ∑ i = 1 N j ⁢ w i , j ⁢ T i , j ) / W j , w i,j being the weight amount of the i th polymer (Pj) of material (Mj), T i,j being the melting temperature of the i th polymer (Pj) of material (Mj), W j being the total weight amount of material (Mj), for j=1 and for j=2, wherein polymer (P2) is a PMXDA.