Microcapsules with walls of reaction products of bluret polyisocyanates and guanidines.

摘要

Microcapsules with walls consisting of or containing reaction products of guanidine compounds (I) and aliphatic polyisocyanates (II) containing biuret groups are claimed. Also claimed are: (1) a method of making the microcapsules; and (2) carbonless copying paper with microcapsules of this type containing dye precursor. Preferably (I) is guanidine carbonate (IA). (II) are technical products based on the biuret of hexamethylene diisocyanate. (II) are used in an amount of 3-15% with respect to the total amount of oil phase to be encapsulated. 0.1-1.0 mole (IA) is used in the aqueous phase per mole isocyanate (NCO) groups present as (II) in the oil phase.