tituted pyrrolidinones; dialkyl- and dicycloalkyl-carbodiimides having from about 5 to about 20 carbon atoms; ##STR3## wherein each R2 is the same or different and is an alkyl, cycloalkyl or aryl, having from 1 to about 12 carbon atoms;R3 is an alkyl, phenyl, alkylphenyl or dialkylaminophenyl, having from 1 to about 20 carbon atoms; Each R4 is the same or different, and is an alkyl or cycloalkyl h