PURPOSE: To obtain a molding material useful for resinous tableware, which is durable for use in a microwave over by kneading resin ingredients consisting of an unsaturated polyester resin, a crosslinking agent and a shrinkage control agent and additive ingredients and forming into a belt-shaped molding material.

CONSTITUTION: 25W50wt% resin ingredients consisting of an unsaturated polyester resin, a crosslinking agent and a shrinkage control agent are mixed with 50W75wt% additive ingredients consisting of a reinforcing agent, a filter, a mold release agent and coloring materials, and the mixture is kneaded and formed into a long belt, which is cut to a given length to give the title molding material. The unsaturated polyester resin used herein may be either liquid or solid at normal temperature. The shrinkage control agents used include a saturated polyester resin, polyethylene and polyvinyl acetate. In respect of moldability and the scattering of strength, the amount of the unsaturated polyester resin in the resin ingredients should preferably be 40W60wt%. In respect of strength and moldability, the amount of the reinforcing agent in the additive ingredients should preferably be 15W35wt%.