| abstract |
The present invention concerns blocked isocyanate crosslinkers based on pentaerythritol for use in thermosetting coatings. More particularly, the invention pertains to thermosetting protective coatings containing a coreactive binder polymer comprising a hydroxyl functional matrix polymer adapted to coreact with a blocked isocyanate comprising pentaerythritol reacted with excess equivalents of isocyanate where excess isocyanate groups are blocked with a blocking agent. Pentaerythritol comprises between about 20% and 100% by weight of the polyol reactants reacted with excess isocyanate groups while the blocked crosslinker comprises between about 10% and 50% by weight of the thermosetting binder components. The preferred thermosetting coating is powder coating. |