Poly(meth)acryl imides with improved coloration

A polymer essentially containing units of the formula I in which R and R are hydrogen or methyl and R is hydrogen, C1-C18-alkyl, C5-C8-cycloalkyl, C6-C10-aryl or C6-C10-aryl-C1-C4-alkyl where these radicals may be up to trisubstituted by radicals selected from the group consisting of C1-C4-alkyl, C1-C4-alkoxy and halogen, obtainable by reacting a polymer based on C1-C20-alkyl esters of methacrylic acid and/or acrylic acid with a primary amine of the formula II R NH2 II in the presence of a compound selected from the group consisting of phosphinic acid and phosphonic acid and the alkali metal, alkaline earth metal and aluminium and ammonium salts thereof, where the ammonium ion may be substituted by up to four C1-C4-alkyl and/or C5-C8-cycloalkyl groups, or mixtures thereof, and a process for the preparation of these polymers, their use for the production of mouldings, and mouldings made from these polymers.