Multimodal polyamides, polyesters and polyester amides

A thermoplastic polymer mixture comprising m polymers Pn, where m is a natural number greater than 1 and n is a natural number from 1 to m, where n is a natural number from 1 to m, where each of the polymers has one or more functional groups of the structure -(R )x-C(O)-(R )y- present as repeat units in the main chain of polymer Pn where x and y, independently of one another, are 0 or 1, and x+y=1 R and R , independently of one another, are oxygen or nitrogen bonded into the main polymer chain, where in the differential distribution curve W(M) determined to DIN 55672-2 in hexafluoroisopropanol as eluent the polymer mixture has at least two maxima of the relative frequency W, and after aging of the polymer mixture at the melting point of the polymer mixture determined to ISO 11357-1 and 11357-3 for 5 minutes, the polymer mixture has in the differential distribution curve W(M) determined to DIN 55672-2 in hexafluoroisopropanol as eluent at least 2 maxima of the relative frequency W, and the position of the maxima here after aging of the polymer mixture at the melting point of the polymer mixture is within three times the recurrent standard deviation sigma(r) of MP in percentage of the value measured to DIN 55672-2, based on the position of the maxima prior to aging of the polymer mixture at the melting point of the polymer mixture.