PURPOSE: To obtain an ultraviolet-curable composition which can give cured films having high modulus by including a specified amounts of a specified silicon resin and a specified organic mercaptan and effective amounts of a photoinitiator and a free radical initiator.
CONSTITUTION: There is provided an ultraviolet-curable silicon resin/organic mercaptan composition essentially consisting of a silicon resin (A) having an average unit represented by the formula (wherein Rs are monovalent organic groups, provided that at least 10 mol.% of them are phenyl groups and that at least two, per molecule, Rs are aliphatic unsaturated groups (X) reactive with SH; and a is 1.2-1.8 on the average) and an organic mercaptan (B) containing C, H, S and O and having at least two SH groups per molecule and effective amounts of a photoinitiator which cures the composition on exposure to ultraviolet rays and a free radical inhibitor which retards gelation during storage, wherein when B has two SH groups per molecule, at least two Xs are present in a molecule of A or when A has two, per molecule SH groups, at least two SH groups are present per molecule of B, the ratio of the SH groups of B to the X groups of A is 0.5-1.5.
AREN BURENTO PUDAA
UIRIAMU EDOWAADO UIRII
