Abstract: The present invention provides a sealant for an optical semiconductor device which is less likely to reduce its luminance and is also less likely to change its color even used in an energized state in harsh environments of high temperature and high humidity. The sealant for an optical semiconductor device includes: a first organopolysiloxane not containing a hydrogen atom bound to a silicon atom, but containing an alkenyl group bound to a silicon atom and an aryl group bound to a silicon atom, a second organopolysiloxane containing a hydrogen atom bound to a silicon atom and an aryl group bound to a silicon atom, and a platinum-alkenyl complex. The platinum-alkenyl complex is a reaction product obtained by reacting chloroplatinic acid hexahydrate with not less than 6 equivalent of a bi- or more-functional alkenyl compound.

Abstract: The present invention provides a sealant for an optical semiconductor device which has high gas barrier property against corrosive gas, and is less likely to crack or is less likely to peel off even when used in harsh environments.

Abstract: Smooth cured coated films having excellent properties are formed by electrodepositing and coating a film on a cathode of an electroconductive material in an electrodeposition bath containing a cationically electrodepositing composition, which is composed of a polymer resin having amino groups and acryloyl or methacryloyl groups and of acrylic or methacrylic acid, and curing the coated film by the irradiation of an ionic radiation.