Dual curing coating method for substrates with shadow areas.

摘要

The invention relates to a method of curing a liquid silicone composition to a crosslinked polymer on a substrate having shadow areas not readily accessible to direct UV light, by: a) applying a liquid composition to the substrate in a manner so as to cover both the light accessible and the shadow areas, the composition comprising a radical photoinitiator and a crosslinkable polyorganosiloxane prepolymer having a plurality of acrylate or methacrylate groups bound thereto and further including a plurality of groups of the formula <CHEM> where R<1> is a hydrolyzable organic group and R<2> is R<1> or, if R<1> is dialkylamino, R<2> is R<1> or hydrocarbyl; b) irradiating the substrate with UV irradiation sufficient to substantially cure the composition in the areas directly accessible to UV light, and c) exposing the composition on the substrate to moisture for sufficient time to cure the composition in the shadow areas. The method is particularly applicable to providing a resistant coating on substrates having raised parts such as electronic circuit boards.