Patent ID: 7862758

Claim:
An in-mold coating method in which a resin molded product is molded and coated in a mold cavity formed between female and male molds, the method comprising: a first step of injecting molten resin into a mold cavity with an injection machine; a second step of molding a resin molded product after injecting of the molten resin into the mold cavity by reducing a volume of the mold cavity in accordance with a thermal contraction of the molten resin to shape the molten resin; a third step of forming a gap for injecting a coating material between a resin molded product and a surface of the mold cavity by slightly opening the mold when the resin molded product solidifies to an extent to which the product can withstand the injecting pressure and flowing pressure of the coating material; and a fourth step of injecting the coating material into the gap and clamping the mold again, wherein mold-clamping forces in the second and fourth steps are controlled so that the deformation of the mold by clamping is substantially the same in the second and fourth steps, and wherein mold-clamping forces used in the second and fourth steps are substantially the same.