This improved atinic radiation-curable compsn. for cast polymerisation comprises (A) 40 to 90 pts. wt. of a urethane poly(meth)acrylate, (B) 10 to 60 pts. wt. of a vinyl monomer, and (C) at least one of the cpds., methyl phenylglyoxylate; 2-hydroxy-2-methyl- 1-phenylpropan-1-one; hydroxycyclohexyl phenyl ketone; a photoinitiator represented by general formula (I), where R1 and R2 independently represent a phenyl, a methyl, an ethoxy, or an isopropyloxy gp. (A) is specified to have two or more (meth)acryloxy gps. per molecule. (B) is specified to have a boiling pt. of 100 deg.C or higher and it should be capable of undergoing radical polymerisation. The amt. of (C) is specified to be 0.005 to 5 pts. wt. per 100 pts. wt. of the sum of components (A) and (B). (B) is at least one monomer of formula (II) and/or (III), where R3, R4, R6 and R7 independently are H, CH3; R5 are a phenyl, a biphenyl, a cyclohexyl, a dicyclopentadienyl or an adamantyl gp.; m and n are independently one of the integers 0, 1, 2 or 3; p is an integer in the range 0-5; R8 is gp.(i) or (ii) where X is H, Cl or Br; R9 is H or CH3; 1 is an integer between 0 and 5. (C) is pref. 2,4,6-trimethylbenzoyl diphenylphosphinoxide. The cast polymerisation product made from this compsn. is produced by radical polymerisation fo the compsn. using actinic radiation.
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