Semi-crystalline polyamide composition with high glass transition temperature for composite material, process for manufacturing same and uses thereof

A composition suitable for a thermoplastic composite material comprising:

• 30% to 60% by volume of a non-reactive thermoplastic matrix comprising from 50% to 100% by weight of a semi-crystalline polyamide polymer and from 0% to 50% by weight of at least one additive and/or of at least one other polymer,
• 40% to 70% by volume of long reinforcing fibers,
• said thermoplastic matrix impregnates said long reinforcing fibers,
• said semi-crystalline polyamide polymer comprises at least one BACT/XT copolyamide in which:
• BACT is a unit comprising an amide unit present at a molar content ranging from 20% to 70%, wherein BAC is chosen from 1,3-bis(aminomethyl)cyclohexyl (1,3-BAC), 1,4-bis(aminomethyl)cyclohexyl (1,4-BAC) and a mixture thereof, and T is terephthalic acid,
• XT is a unit comprising an amide unit present at a molar content ranging from 30% to 80%, wherein X is a C9 to C18 linear aliphatic diamine, and wherein T is terephthalic acid,
• in the BACT and/or XT units, independently of one another, up to 30 mol % relative to the total amount of dicarboxylic acids, of the terephthalic acid can be replaced with other aromatic, aliphatic or cycloaliphatic dicarboxylic acids comprising 6 to 36 carbon atoms, and
• in the BACT and/or XT units, independently of one another, up to 30 mol % of the BAC and/or where appropriate of X, relative to the total amount of diamines, can be replaced with other diamines comprising from 4 to 36 carbon atoms, and
• in the copolyamide, no more than 30 mol %, relative to the total amount of monomers, can be formed by lactams or aminocarboxylic acids, and
• on condition that the sum of the monomers which replace the terephthalic acid, the BAC and X does not exceed a concentration of 30 mol %, relative to the total amount of monomers used in the copolyamide, and
• on condition that BACT and XT units are always present in said polyamide polymer.