A METHOD FOR THE PREPARATION OF MICROCAPSULES

摘要

Microcapsules are prepared by adding a methylolated melamine or methylolated urea to an aqueous emulsion of the core material dispersed in an aqueous solution of a styrene/maleic anhydride copolymer partially hydrolyzed in an alkaline condition and heating the mixture at 40 to 90 DEG C in an acidic condition so that a reaction product forming the capsule walls is produced by the esterification reaction between the carboxyl groups in the partial hydrolysis product and the methylol groups in the methylolated melamine or urea and the amidation reation between the carboxylic anhydride groups in the former and the amino groups in the latter. By virtue of the three dimensional network structure, the capsule walls are very dense and highly resistant against heat, water and solvents.