Abstract: The invention relates to a cationic photocurable composition comprising at least one cationically polymerizable compound, at least one onium salt photoinitiator, at least a moisture scavenger, and at least a stabilizer selected from the group consisting of sterically hindered nitroxyl stabilizers, sterically hindered phenolic antioxidants, organic phosphorous stabilizers and mixtures thereof.

Abstract: The invention relates to a cationic photocurable composition comprising at least one cationically polymerizable compound, at least one onium salt photoinitiator, at least a moisture scavenger, and at least a stabilizer selected from the group consisting of sterically hindered nitroxyl stabilizers, sterically hindered phenolic antioxidants, organic phosphorous stabilizers and mixtures thereof.

Abstract: A photopo1ymerisation process for the production of mouldings from methacrylate casting resins wherein 1) a methacrylate casting resin formulation containing (A1)>50% methyl methacrylate and/or a prepolymerisate containing a high proportion of methyl methacrylate, (A2) 0 to 40% other monomers than can be copolymerised with methyl methacrylate, (B) 0.1 to 10% at least one mono- or bis-acyiphosphine oxide photoinitiator, C) 0 to 10% other photoinitiators, D) 0 to 5% thermal initiators and E) optionally further customary additives is cast in a mould and 2) is fully cured by irradiation with a light source in the range of from 200 to 800 nm to form a mechanically stable moulding.