Process for the production of plastics by the polyisocyanate polyaddition process and catalysts suitable for this process

A process for the production of optionally cellular polyurethane by the isocyanate polyaddition process which comprises reacting

• a) a polyisocyanate with
• b) a compound containing at least two isocyanate-reactive groups and
• c) a catalyst comprising one or more triamino(imino)phosphoranes corresponding to the following formulas ##STR11## wherein R represents hydrogen, a linear or branched alkyl group containing 1 to 8 carbon atoms, a cycloalkyl or alkylcycloalkyl group containing 5 to 9 carbon atoms, an aryl group or an alkylaryl group,
• R' represents a linear or branched alkyl group containing 1 to 8 carbon atoms, a cycloalkyl or an alkylcycloalkyl group containing 5 to 9 carbon atoms or a cycloalkylene group containing 4 to 6 carbon atoms,
• R" represents hydrogen, a linear or branched alkyl group containing 1 to 8 carbon atoms, a cycloalkyl or an alkylcycloalkyl group containing 5 to 9 carbon atoms, an aryl group or an alkylaryl group,
• R"' represents a linear or branched alkyl group containing 1 to 8 carbon atoms, a cycloalkyl or an alkylcycloalkyl group containing 5 to 9 carbon atoms, an aryl group or an alkylaryl group and
• n and m may be the same or different and represent 0, 1, or 2.