Patent ID: 7777054

Claim:
A uretonimine-modified isocyanate composition having reduced color, said uretonimine-modified isocyanate composition comprising: a polyisocyanate composition having two or more isocyanate groups and comprising 4,4′-diphenylmethane diisocyanate (MDI); a catalyst for catalyzing a reaction of said isocyanate groups to form carbodiimides available for forming uretonimines and uretonimine oligomers; a first quenching agent present in an amount of from about 1 to about 500 parts per million based on said uretonimine-modified isocyanate composition and having a pKa of greater than about −8.0 for partially quenching the reaction of said isocyanate groups to inhibit formation of carbodiimides thereby inhibiting additional formation of the uretonimine and uretonimine oligomers; and a second quenching agent different than said first quenching agent and present in an amount of from about 1 to about 250 parts per million based on said uretonimine-modified isocyanate composition and having a pKa of less than about −8.0 for quenching the reaction of said isocyanate groups to further inhibit formation of the carbodiimides thereby further inhibiting additional formation of uretonimines and uretonimine oligomers.