Patent ID: 7151136

Claim:
A polyamide-based thermoplastic composition comprising, based on a total of 100 parts by weight of (A1), (A2) and (B) or (B′): 61 to 98 parts of a polyamide (A1) nondiamine; 0.2 to 9 parts of a polyamide (A2) diamine, the chain of said polyamide (A2) being different from that of the polyamide (A1) said polyamide (A2) being immiscible with said polyamide (A1) nondiamine and the ratio by mass (A2)/(A1) being less than 1; 1 to 30 parts of at least one reactive impact modifier (B) or of a blend (B′) comprising at least one impact modifier and at least one reactive modifier, in which the melting temperature of the polyamide (A2) diamine or, if it is amorphous, its glass transition temperature (Tg) is less than the melting temperature of the polyamide (A1) nondiamine or, if it is amorphous, less than its glass transition temperature (Tg), in which the difference between the melting temperatures of (A1) and (A2) or between the melting temperature of one and the Tg of the other or between the Tg values of (A1) and (A2), according to the individual case, is between 15 and 50° C., the melting temperatures and the Tg values being measured by DSC (Differential Scanning Calorimetry), and wherein the impact value at +23° C. and/or at −40° C., measured according to the ISO CN standard 179:93, of said composition comprising x parts of (A1), y parts of (A2) and z parts of reactive impact modifier (B) or of blend of modifiers comprising at least one reactive impact modifier (B) or of blend (B′) comprising at least one impact modifier and at least one reactive modifier is greater by at least 25% than the impact value at +23° C. and/or at −40° C. respectively of a thermoplastic composition not comprising polyamide (A2) diamine but comprising x parts of the same polyamide (A1) nondiamine compound and (z+y) parts of the same reactive impact modifier compound (B) or of the same blend of modifiers comprising at least one reactive impact modifier (B) or of the same blend (B′) comprising at least one impact modifier and at least one reactive modifier.