Plating adhesion good polyorganosiloxane coating composition and the coating film

摘要

PROBLEM TO BE SOLVED: To provide a polyorganosiloxane coating material composition excellent in coating material stability, capable of making a thick coating film, and excellent in reflectivity, light resistance, insulating properties and plate adhesion.SOLUTION: The polyorganosiloxane composition includes (A) 30.1-74.9 pts.wt. of a reactive polyorganosiloxane compound obtained by hydrolytic condensation of components (a) to (c), in the presence of an organic acid catalyst, wherein the (a) is 73-95.5 pts. of methyltrialkoxysilane, (b) is 0.5-12 pts. of alkoxysilane having a substituent selected from among a glycidyl group, 3,4-epoxycyclohexyl group, mercapto group and sulfide group, and (c) 4-15 pts. of a silicon oligomer containing a methyl group and an alkoxy group; (B) 25-59.9 pts.wt. of rutile-type titanium dioxide with average particle size of 0.2-0.3 m; and (C) 0.1-10 pts.wt. of rutile-type titanium dioxide microparticles having average primary particle size of 10-70 nm, the microparticles being surface-treated with alumina and zirconia.