The present invention is directed to a process for the production of optionally foamed polyurethanes which are combined or fabricated with another material, comprising reacting compounds with molecular weights from 400 to 10,000 containing at least 2 isocyanate reactive hydrogen atoms with polyisocyanates in the presence of catalysts containing tertiary amino groups and combining or fabricating the resulting polyurethane with another material, characterized in that the catalysts used are diffusion resistant aminoalkanols corresponding to the general formula ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 may be identical or different and represent hydrogen or a C.sub.1 -C.sub.6 alkyl group,R.sup.5, R.sup.6, R.sup.7 and R.sup.8 may be identical or different and represent a C.sub.1 -C.sub.6 alkyl group or together form a C.sub.2 -C.sub.6 alkylene group which may contain hetero atoms such as O or NR (R=C.sub.1 -C.sub.4 alkyl), and n and m may be identical or different and represent integers from 1 to 6.