UV-moisture dual cure silicone conformal coating compositions with improved surface tack

A radiation- and moisture-curable silicone composition which in exposure to radiation is surface cured to form a firm, non-tacky surface skin overlying a bulk interior moisture-curable volume of the composition, said composition comprising:

• a first silicone fluid comprising a silicone endcapped with vinyl functionality, said endcapped silicone being the reaction product of a silanol-terminated silicone having at least 60 mole percent Si-OH terminal groups and a viscosity, at room temperature, of 1000 centipoise or less and a silane cross-linker having at least one vinyl functional group and at least 2 hydrolyzable functional groups;
• a second silicone fluid having both radiation-curable (meth)acryl functional groups and moisture-curable hydrolyzable groups;
• and
• a photoinitiator effective for radiation curing of the silicone composition,
• wherein the mole ratio of the vinyl functional groups to the (meth)acryl functional groups is from 5:95 to 4:6.