Patent ID: 8445623

Claim:
A process for continuously preparing a polyisocyanate comprising a biuret structure comprising continuously reacting an excess amount of an organic isocyanate (A) comprising exclusively aliphatically and/or cycloaliphatically bonded isocyanate groups with an organic amine (B) comprising exclusively aliphatically and/or cycloaliphatically bonded primary amino groups by a) mixing a first amount of said organic isocyanate (A) with said organic amine (B) at a temperature above 170° C. to form a reaction mixture stream, and b) metering a second amount of said organic isocyanate (A) at a temperature in the range of from 20 to 250° C. into said reaction mixture stream of a), wherein the ratio of the parts by weight of said organic isocyanate (A) fed per unit time into step a) to the parts by weight of said organic isocyanate (A) fed per unit time into b) is in the range of from 1:9 to 9:1, and the ratio of the total number of NCO groups fed per unit time into both steps a) and b) to the number of NH 2 groups fed in per unit time into step a) is at least 4:1.