PURPOSE: The titled composition to which is imparted excellent curability by improving curing inhibition by oxygen, containing a specified allyl ether group- containing compound as a reactive diluent.

CONSTITUTION: An ultraviolet-curable resin composition, prepared by adding a compound of the formula as a reactive diluent in place of or inconjunction with a conventional reactive diluent to a prepolymer having an ethylenically unsaturated bond. When a conventional reactive diluent is added to the prepolymer, the resulting composition can not form a cured product having a smooth surface by irradiation with ultraviolet rays in the presence of oxygen, because the inhibitory action of oxygen upon radical polymerization causes the surface in contact with oxygen (air) to remain sticky. Although there are a process in which the curing is performed in an inert gas atmosphere and a process in which an amine is used, these processes have a drawback that a special apparatus must be used, or the addition of an amine sometimes causes loss of the weather resistance of a cured film. By using the compound of the formula, it is possible to obtain an ultraviolet curable resin composition freed from the above drawback and having excellent curability.