Patent ID: 7790907

Claim:
A method of producing a uretonimine-modified isocyanate composition having increased low-temperature tolerance, said method comprising: providing a first polyisocyanate composition having two or more isocyanate groups and comprising 4,4′-diphenylmethane diisocyanate (MDI); reacting the first polyisocyanate composition at a temperature of from about 90° C. to about 115° C. and in the presence of a catalyst such that the isocyanate groups form carbodiimides for forming uretonimine and uretonimine oligomers; quenching the reaction of the first polyisocyanate composition with a quenching agent to produce an intermediate composition having an intermediate isocyanate value of from about 23.0 to about 25.0; and combining the intermediate composition with a second polyisocyanate composition in an amount sufficient that the uretonimine-modified isocyanate composition has a final isocyanate value of from about 29.5 to about 33.5.