Radiation curable coating compositions containing an acrylate-capped, polyether urethane and a polysiloxane

Claim 1

A radiation curable coating composition, convertible to a hard, flexible coating having inherent surface lubricity, comprising: (A) from 5 to 70 weight percent of an acrylate-capped polyether urethane of the formula ##STR16## wherein Z is hydrogen or methyl; R is C m H 2m ; X is the residue of a polyether glycol having an average molecular weight from 300 to 4,000 after its reaction with an organic diisocyanate; Y is the residue of an organic diisocyanate after its reaction with a polyether glycol and a hydroxyalkyl acrylate; m has a value from 1 to 5; and n has a value from 1 to 5; (B) from 80 to 5 weight percent of a low molecular weight polyfunctional acrylate having an average molecular weight of from 170 to 1,200 and defined by the formula ##STR17## wherein D is hydrogen or methyl, x is 1 or 2, R 2 is chosen from the group consisting of ##STR18## wherein Q is hydrogen or --O--, G is --O-- or ##STR19## M is hydrogen or alkyl having 1 to 2 carbon atoms, p has a value of 1 to 3, q has a value of 2 to 6, r has a value of 2 to 15, r' has a value of 2 to 4 and R' is the residue of an organic diisocyanate after its reaction with a hydroxyalkyl acrylate; (C) from 0.1 to 2.0 weight percent of a polyether-functional polysiloxane chosen from the group of compounds represented by the formulas: ##STR20## and MeSi[ (OSiMe 2 ) f M' ] 3 wherein R 3 is alkylene having from 1 to 4 carbon atoms; R 4 is alkyl having from 1 to 4 carbon atoms; at least 50% of the M' units have the structure ##STR21## and the remaining M' units are lower alkoxy; Me is methyl; f has a value from 10 to 100; g has a value from 1 to 20; and s to t are numbers such that the molecular weight of the polyoxyalkylene units is from 1,200 to 3,000 and from 20 to 80 weight percent of the oxyalkylene units are oxyethylene; (D) from 0.5 to 80 weight percent of a monofunctional acrylate having a molecular weight of from 100 to 400; and (E) from 0 to 15 weight percent of a photoinitiator.