Microcapsules having walls made of polyisocyanate/guanidine reaction products

摘要

Microcapsules with walls comprising or contg. reaction prods. (A) of guanidine cpds. (B) and polyisocyanates (C). Also claimed are (i) the prepn. of the microcapsules, and (ii) carbon-free carbon paper contg. microencapsulated dye precursors in which the microcapsule walls comprise (A).