Polyamide microcapsules reacted with isocyanate emulsion

摘要

Polyamide microcapsules are reacted with an isocyanate emulsion to reduce microcapsule yellowing and decrease microcapsule permeability when used in carbonless copying systems. The isocyanate reacts with the surface of the polyamide shell to close discontinuities in the shell and improve impermeability. The isocyanate also reacts with free amines in the capsule slurry to reduce the presence of free amines that cause yellowing.