Process for producing substrate for optical recording medium

A process for producing an optical recording medium, comprising an epoxy resin substrate having hard coating layers formed on both sides thereof, which process comprises:

• (i) the step of coating and drying a solution containing a radiation-curable resin composition on one side of each of two glass plates having surface flatness and subjecting the coating films to radiation to cure them,
• (ii) the step of arranging the two glass plates having the cured coating films so that the coating films face each other, and sealing three sides of the two glass plates with a spacer to form a liquid-casting mold having a cavity;
• (iii) the step of casting into the cavity of the mold an epoxy resin composition comprising an alicyclic epoxy resin or a mixture of an alicyclic epoxy resin and an aromatic epoxy resin, an organic polybasic acid anhydride, a curing accelerator, and an anti-discoloring agent, and heat-curing the epoxy resin composition to integrate it with the coating films and provide a three-layer transparent optical recording medium within the mold, and
• (iv) the step of recovering the integrated transparent three-layer product from the mold to effect release between the glass faces and the coating films and to transfer the coating films to both sides of the cured epoxy resin substrate.