Ink-repellent coatings composed of silicone-acrylic block copolymer for ink jet printer

The silicone-acrylic block copolymers were prepared by free radical copolymerization, in which we used polydimethylsiloxane containing azo groups as a macromolecular initiator and acrylic monomers including functional monomers. The copolymer solutions were coated on substrates by various application methods, subsequently cured with either cross-linking agents or UV light. Advancing (theta(A)) and receding (theta(R)) contact angles of the resulting films were measured in various inks. The films were hard enough for a nozzle face, exhibited over 80degrees of theta(A) and 60degrees of theta(R) in an ink, which were superior to those of silicone or fluorinated coating films. The ink-resistance of the films was evaluated by changes in theta(A) and theta(R) before and after soaking the films into inks at 60degreesC for 4 weeks. The durability of the films were outstanding. The excellent properties were found to be caused by microdomain structure and to be influenced by domain spacing rather than silicone content.