Ink repellent coatings consisting of silicone-acrylic block copolymer for ink jet printers

Various silicone-acrylic block copolymers were prepared by a free radical c opolymerization technique, in which we used poly(dimethylsiloxane) containi ng azo groups as a macromolecular initiator in reactions with acrylic monom ers, including functional monomers. The copolymer solutions were coated ont o substrates by using various application methods and subsequently cured by using either crosslinking agents or UV light. Advancing (theta (A)) and re ceding (theta (R)) contact angles of the resulting films were measured in V arious inks. These films were found to be hard enough to form a nozzle face , and exhibited over 80(degrees) of theta (A) and 60 degrees of theta (R) w hen in an ink, which are superior values to those observed for 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 in v arious inks at 60 degreesC for 4 weeks. The durability of the films was out standing. The excellent properties were found to be attributable to the for mation of a microdomain structure, and to be influenced by domain spacing r ather than silicone content.