Dual curing systems based on UV curing and alkoxy-silane groups condensation

The use of dual curing systems was proposed in order to overcome some problems and unsatisfactory properties presented by UV curable coatings, mainly with respect to adhesion and mechanical properties. In these systems two types of functional groups are present, one sensitive to the radical curing reaction induced by UV radiation (generally acrylic d. b.) , the other suitable to react according to a different mechanism which is normally chosen among thermal curing processes, at high or room temperature, as well in the presence of epoxy or Isocyanate groups. The use of alkoxy-silane derivatives as coupling agents, mainly for glass fibers, is well known; the condensation reaction between the silanolic groups of the organic network and the ones on the glass surface yields very strong siloxane bonds. Moreover the use of these compour)d as adhesion promoters for metal substrates was reported in the literature. Therefore the study' of a dual curing system based on UV curing and alkoxy-silane groups condensation seems to be interesting In order to achieve particular film properties (e.g. adhesion on glass substrates) or to modify the network structure.