Isocyanate blocked imidazoles and imidazolines for epoxy powder coating
AssigneeAir Products and Chemicals, Inc.
InventorsBurton D. Beitchman, Philip J. Zaluska
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Abstract
This invention relates to the use of an isocyanate blocked imidazole or imidazoline compound as a catalyst for effecting cure of powdered epoxy resins. The isocyanate blocked imidazole or imidazoline imparts an extended pot life to a curable epoxy powder coating composition while effecting cure at substantially lower temperatures than normally would be required and with faster cure times.
Claims16
In a process for curing a finely divided 1-2 epoxy resin having a lower softening point of not less than 40.degree. C. by heating said epoxy resin to an elevated temperature in the presence of a catalyst, the improvement which comprises heating said epoxy resin in the presence of a blocked adduct formed by reacting a polyisocyanate with a secondary amine represented by the formula:
- ##STR2## wherein R.sub.2 is hydrogen, hydrocarbyl, or inertly-substituted hydrocarbyl;
- and
- R.sub.3 and R.sub.4 are each independently hydrogen, hydrocarbyl or inertly-substituted hydrocarbyl provided that R.sub.3 and R.sub.4 are not fused into an aromatic ring.
Dependencies are inferred from the claim text.