PURPOSE: To obtain an undercoating agent which is suitable for release paper easy to recover and which, even when a solvent-base silicone resin is applied to the base paper, does not allow the silicone resin to penetrate into the paper layer, by using as the principal constituent an aqueous resin made by the emulsion polymerization of a radical-polymerizable monofunctional vinyl monomer in the presence of PVA and water.

CONSTITUTION: This undercoating agent contains as the principal constituent an aqueous resin obtained by the emulsion polymerization of a radical- polymerizable monofunctional vinyl monomer in the presence of polyvinyl alcohol and water. The undercoating agent can be applied by a wire bar, a blade coater, an air knife coater, a roll coater, etc. For drying, a drying device such as an oven or a drum drier can be used. The undercoated paper may be calendered for adjustment to a desired degree of smoothness.