Patent ID: 7893184

Claim:
A process for preparing dendritic or hyperbranched polyurethanes by 1) reacting diols or polyols having at least one tertiary nitrogen atom and at least two hydroxyl groups of differing reactivity toward isocyanate groups with diisocyanates or polyisocyanates to form an addition product, with the diols or polyols and diisocyanates or polyisocyanates being selected so that the addition product has, on average, one isocyanate group and more than one hydroxyl group or one hydroxyl group and more than one isocyanate group, 2) converting the addition product from step 1) into a polyaddition product by intermolecular reaction of the hydroxyl groups with the isocyanate groups, and with a reaction with a compound containing at least two hydroxyl groups, mercapto groups, amino groups or isocyanate groups also being able to be carried out first, 3) if desired reacting the polyaddition product from step 2) with a compound containing at least two hydroxyl groups, mercapto groups, amino groups or isocyanate groups wherein only or predominantly the hydroxyl groups of the diols or polyols having the higher reactivity toward isocyanate groups are reacted with the isocyanate groups in step 1) and the hydroxyl groups of the diols or polyols having the lower reactivity toward isocyanate groups are reacted in step 2).