Radiation curable compositions containing acrylic copolymers and isobutylene type.

A radiation curable composition comprising: (a) a copolymer consisting of not gelled residues having the following structural unit: (see formula) wherein n is an integer of 1 to 10,000; R 1 is a C1 to C4 linear or branched; R 2 is selected from the group consisting of methyl, alkyl C2 to C20 linear, cyclic or branched, alkenyl, aryl, alkaryl and aralkyl; R 3 is capable of undergoing a polymerization reaction when exposed to actinic radiation or ionizing radiation and is independently selected at each occurrence the group consisting of a moiety comprising an epoxy group, a moiety comprising a thiol group, (See formula ) in which R 5 is selected from the group consisting of a C6 to C24 alkenyl group containing 1 to 4 ethylenically unsaturated groups and linear or branched alkenyl groups C3 to C8 comprising at least one ethylenically unsaturated group; each occurrence R 6 is independently selected from the group consisting of hydrogen, C 1 alkyl to C 20 linear, cyclic or branched, alkenyl, aryl, alkaryl, aralkyl, alkylol, aralquilol, alkyl thiol and aralkyl thiol, and -COOR 9, wherein R 9 is selected from hydrogen and C1 to C4 alkyl; R 7 is selected from the group consisting of H and C1 to C4 alkyl; each occurrence of R 8 is independently selected from the group consisting of H and C1 to C4 alkyl; R 40 is a linking group selected from C 2 to C 20 linear, cyclic or branched, alkenylene, arylene, alkarylene, aralkylene, oxialcaleno and polyoxyalkalene; i is 1 to 10; j is 0 to 100; and (b) at least one photosensitizer or photoinitiator.