Silicone composition, a release sheet, a release film and methods for preparing the release sheet and the release film

Abstract

The object of the present invention is to provide a silicone composition which provides a release coating having excellent adhesion to a substrate, in particular a plastic film substrate, such as a polyester film. Further, an object of the present invention is to provide a release sheet having a cured coating of the silicon composition. It is also an object of the present invention to provide a silicone composition which has improved storage stability and does not cause separation of the functional compound during long-term storage or transportation. The present invention provides a silicone composition comprising the following components (A) to (C): (A) an organopolysiloxane having at least two alkenyl groups each bonded to a silicon atom in a molecule, having a viscosity at 25 degrees C. in the range of from 50 mPa·s to 10,000 mPa·s, and having no aryl nor aralkyl group bonded to a silicon atom, wherein a percentage of the number of the alkenyl groups relative to the number of groups each bonded to a silicon atom is from 0.01% to less than 4.5%; (B) a mixture comprising the following components (B1), (B2) and (B3): (B1) an alpha-olefin which is liquid at 25 degrees C., in an amount of 0.05 to 15 parts by mass, relative to 100 parts by mass of component (A), (B2) an organohydrogenpolysiloxane having at least three hydrogen atoms each bonded to a silicon atom in a molecule, and having no aryl nor aralkyl group bonded to a silicon atom, wherein a ratio of the number of the SiH groups present in component (B2) to a total number of the alkenyl groups present in components (A) and (B) is 0.5 to 10; (B3) an organohydrogenpolysiloxane having at least three hydrogen atoms each bonded to a silicon atom in a molecule, and having an aryl group and/or an aralkyl group each bonded to a silicon atom such that a percentage of the number of the aryl group and the aralkyl group relative to a total number of hydrogen atoms and groups each bonded to a silicon atom is 8% to 50%, wherein the amount of component (B3) is from 0.05 to 10 parts by mass, relative to 100 parts by mass of component (A), and a ratio of the number of the SiH groups present in component (B3) to a total number of the alkenyl groups present in components (A) and (B) is 0.1 to 2; and (C) a catalytic amount of a platinum group metal catalyst.

Dependencies are inferred from the claim text.