| abstract |
The invention relates to a process for the preparation of a compound containing polyisocyanate and isocyanurate groups through trimerisation of 1,4-tetramethylenediisocyanate (TMDI), using a trimerisation catalyst, and the purification of the trimer desired, characterised in that the trimerisation is effected at a temperature below 90°C, the purification being effected through extraction, using an apolar solvent with a boiling point below 180°C, and evaporation of the solvent under lowered pressure, at a temperature below 90°C. |