A process for preparing a polyamide having a melting temperature T M by polymerization from a reaction mixture at a reaction temperature T R, wherein the reaction mixture comprises the following components: at least one lactam at least one diamine of the general formula in which R 1, R 2 independently of one another are selected from C 1 -C 10 alkanediyl, at least one dicarboxylic acid derivative selected from the group consisting of a dicarboxylic acid of the general formula, a dicarboxylic ester of the general formula, and a dinitrile of the general formula HOOC-R 3 -COOH R 5 OOC-R 4 -COOR 6 NC-R 7 -CN in which R 3, R 4 and R 7 independently of one another are selected from the group consisting of a bond, unsubstituted or at least monosubstituted C 1 -C 40 alkanediyl, and unsubstituted or at least monosubstituted C 6 -C 40 arylene, where the substituents are selected from the group consisting of F, Cl, Br, I, OR 8, C 1 -C 10 alkyl, and C 6 -C 10 aryl, where R 8 is selected from the group consisting of H and C 1 -C 10 alkyl; R 5 and R 6 independently of one another are selected from the group consisting of unsubstituted or at least monosubstituted C 1 -C 20 alkyl, unsubstituted or at least monosubstituted C 6 -C 20 aryl, and unsubstituted or at least monosubstituted C 6 -C 20 aralkyl, where the substituents are selected from the group consisting of F, Cl, Br, I, OR 9, and C 1 -C 10 alkyl, where R 9 is selected from the group consisting of H and C 1 -C 10 alkyl; and water. at least one lactam at least one diamine of the general formula in which R 1, R 2 independently of one another are selected from C 1 -C 10 alkanediyl, at least one dicarboxylic acid derivative selected from the group consisting of a dicarboxylic acid of the general formula, a dicarboxylic ester of the general formula, and a dinitrile of the general formula HOOC-R 3 -COOH R 5 OOC-R 4 -COOR 6 NC-R 7 -CN in which R 3, R 4 and R 7 independently of one another are selected from the group consisting of a bond, unsubstituted or at least monosubstituted C 1 -C 40 alkanediyl, and unsubstituted or at least monosubstituted C 6 -C 40 arylene, where the substituents are selected from the group consisting of F, Cl, Br, I, OR 8, C 1 -C 10 alkyl, and C 6 -C 10 aryl, where R 8 is selected from the group consisting of H and C 1 -C 10 alkyl; R 5 and R 6 independently of one another are selected from the group consisting of unsubstituted or at least monosubstituted C 1 -C 20 alkyl, unsubstituted or at least monosubstituted C 6 -C 20 aryl, and unsubstituted or at least monosubstituted C 6 -C 20 aralkyl, where the substituents are selected from the group consisting of F, Cl, Br, I, OR 9, and C 1 -C 10 alkyl, where R 9 is selected from the group consisting of H and C 1 -C 10 alkyl; and R 3, R 4 and R 7 independently of one another are selected from the group consisting of a bond, unsubstituted or at least monosubstituted C 1 -C 40 alkanediyl, and unsubstituted or at least monosubstituted C 6 -C 40 arylene, where the substituents are selected from the group consisting of F, Cl, Br, I, OR 8, C 1 -C 10 alkyl, and C 6 -C 10 aryl, where R 8 is selected from the group consisting of H and C 1 -C 10 alkyl; R 5 and R 6 independently of one another are selected from the group consisting of unsubstituted or at least monosubstituted C 1 -C 20 alkyl, unsubstituted or at least monosubstituted C 6 -C 20 aryl, and unsubstituted or at least monosubstituted C 6 -C 20 aralkyl, where the substituents are selected from the group consisting of F, Cl, Br, I, OR 9, and C 1 -C 10 alkyl, where R 9 is selected from the group consisting of H and C 1 -C 10 alkyl; and water.