Coating of fine particles in polyurethane block copolymer binder

摘要

Coating of fine particles such as magnetizable particles in a binder which is a soluble hydroxyl-terminated polyurethane block copolymer comprising soft or flexible blocks synthesized from polyester or polyether diols and hard blocks synthesized from aliphatic diols containing tertiary amine and p,p'-diphenylmethane diisocyanate. The block copolymer is capable of dispersing as well as acting as a binder for the particles.