Patent ID: 7339020

Claim:
A process for preparing high-functionality polyisocyanates having at least three free isocyanate groups, which comprises (i) preparation of an addition product (A) which contains only one group which is reactive toward isocyanate and at least two free isocyanate groups by reacting (a) a diisocyanate or polyisocyanate I with (b1) compounds having at least three groups which are reactive toward isocyanate or (b2) compounds containing two groups which are reactive toward isocyanate or mixtures of (b1) and (b2), where the diisocyanate or polyisocyanate I used is tetramethylene diisocyanate, tetramethylene diisocyanate trimer, hexamethylene diisocyanate, hexamethylene diisocyanate trimer, dodecyl diisocyanate, isophorone diisocyanate trimer, 4-isocyanatomethyloctamethylene 1,8-diisocyanate, diphenylmethane 4,4′-diisocyanate or a mixture thereof, and component (b) has functional groups having differing reactivities toward the functional groups of the other component and the reaction ratio is selected so that the addition product (A) contains an average of only one group which is reactive toward isocyanate, and at least two free isocyanate groups, (ii) optionally, intermolecular addition reaction of the addition product (A) to form a polyaddition product (P) containing an average of only one group which is reactive toward isocyanate and an average of more than two free isocyanate groups, and (iii) reaction of the isocyanate reactive group of said addition product (A) and/or the polyaddition product (P) with a diisocyanate or polyisocyanate II to form a high-functionality polyisocyanate having at least three free isocyanate groups and no free isocyanate reactive groups.