The invention relates to the use of copolyamides containing at least two different units A and X1Y of formula A/X1Y for preparing composite materials. Wherein A refers to repeating units obtained by polycondensation of at least one C9-C18 amino acid, preferably C10-C18, more preferably C10-C12 amino acid, or at least one C9-C18 lactam, preferably C10-C18, more preferably C10-C12 lactam, or at least one C4-C36 diamine Ca and at least one C4-C36 dicarboxylic acid Cb, preferably C6-C18, more preferably C10-C12. X1Y represents repeating units derived from the polycondensation of at least one C9-C18 linear aliphatic diamine X1, preferably C10-C18, and at least one aromatic dicarboxylic acid Y. The composite material contains 35-65 wt% of reinforcing fibers, preferably 50-65 wt% based on the total weight. After standardized conditioning, the flexural modulus or tensile modulus of the composite material varies by no more than 20% within the temperature range of 20℃ to 40℃, especially 0℃ to 40℃, and further particularly -10℃ to 40℃.

Area Code: FR

Application Number: CN202080032776.5