| 摘要 |
The present invention relates to a polyisocyanates containing allophanate groups and optionally isocyanurate groups that are prepared by reacting compounds which i) are substantially free of hydroxyl groups and isocyanate groups, ii) have an average of at least two urethane groups per molecule and iii) are the reaction products of linear or branched, aliphatic isocyanates with organic hydroxyl compounds, with an excess quantity, based on the urethane groups, of 4,4'-bis-(isocyanatocyclohexyl)-methane to form polyisocyanates containing allophanate groups and optionally isocyanurate groups and optionally removing at least a portion of the unreacted excess 4,4'-bis-(isocyanatocyclohexyl)-methane. The present invention also relates to a process for the production of these polyisocyanates and to their use as binders or binder components in coating compositions.
|
