Abstract: The present invention relates to a process for preparing olefin-CO terpolymers with the steps of: providing a reactor; charging the reactor with a first, gaseous olefin and with CO, such that there is a first pressure p1 in the reactor; reacting the first olefin with CO in the presence of a catalyst in the reactor; wherein a second olefin is initially charged in the reactor and/or metered in during the reaction, prior to the reaction either no CO is present in the reactor or the volume ratio of first, gaseous olefin to CO is >60:40, and during the reaction the average over time of the volume ratio of gaseous olefin metered in to CO metered in is >60:40.

Abstract: A process for preparing olefin-CO copolymers with the steps of: providing a reactor; charging the reactor with a gaseous olefin and with CO, such that there is a first pressure p1 in the reactor; and reacting olefin with CO in the presence of a catalyst in the reactor. Prior to the reaction, either no CO is present in the reactor or the volume ratio of gaseous olefin to CO is ?90:10. During the reaction, gaseous olefin and CO are metered in at least intermittently, with an average over time of the volume ratio of the olefin metered into CO metered in of ?90:10.