Polyisocyanates containing allophanate groups

Abstract

The present invention relates to a process for preparing polyisocyanates containing allophanate groups by reacting compounds a), which i) contain urethane groups, but which are substantially free of hydroxyl groups and isocyanate groups, ii) have an average of at least two urethane groups per molecule, iii) are prepared by reacting organic isocyanates a1) with organic hydroxyl compounds a2) and iv) have an average molecular weight of at most 2,500, with excess quantities, based on the urethane groups, of distillable organic polyisocyanates b) to form polyisocyanates containing allophanate groups and subsequently removing by distillation the unreacted excess of component b) to a residual content of less than 0.5 wt. %, provided that polyisocyanates a1) and polyisocyanates b) are different. The present invention also relates to the products obtained from this process and to their use as binders or binder components in coating compositions.

Dependencies are inferred from the claim text.