Particularly preferred polyamines are those in which R8 and R9 stand for identical or different simple alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert.-butyl, n-pentyl or n-hexyl groups and at least one of the groups denoted by R8 and R9 is a group obtainable by the addition of an amine hydrogen atom to an olefinically unsaturated compound.