Composites comprising an aramid matrix

A combination of 10-80% by volume of reinforcing fibres and 20-90% by volume of thermoplastic fibres or films suitable to be formed into a composite structure, the thermoplastic fibres or films essentially consisting of an amorphous copolyamide built up of units derived from at least two different dicarboxylic acids and at least two different diamines, of which the divalent aromatic radicals are linked together by amide bonds selected from the groups P1, P2, Q1 and Q2,

• P1:
• 1,4-phenylene, 1,5-naphthylene, 2,6-naphthylene and 4,4'-diphenylene;
• P2:
• radicals of the formula:
• ##STR3## where X=--C(Y)(Y')--, --O--, --S--, --SO.sub.2 -- or --CO--, and Y,Y' are the same or different and represent hydrogen or C.sub.1-4 alkyl, or together cyclohexyl;
• Q1:
• 1,3-phenylene, 1,6-naphthylene, 2,7-naphthylene and 3,4'-diphenylene;
• Q2:
• radicals of the formula:
• ##STR4## where X=--C(Y)(Y')--, --O--, --S--, --SO.sub.2 -- or --CO-- and Y,Y' are the same or different and represent hydrogen or C.sub.1-4 alkyl, or together cyclohexyl;
• each group including the radicals which per aromatic ring comprise 1-4 substituents R, where R may be the same or different and may stand for C.sub.1-4 alkyl, C.sub.1-4 alkoxy, Cl, F, aryl, ortho-fused benzeno or aryl-C.sub.1-4 -alkyl, with the proviso that expressed as the mole fraction of the total of amide bonds the proportion of none of the monomer units is higher than 0.32, the proportion of radicals selected from the groups P1 and P2 together is in the range of 0.18 to 0.82, the proportion of the radicals selected from the groups Q1 and Q2 together is in the range of 0.18 to 0.82, and the proportion of the radicals from the group Q2 is at least 0.15.