| 摘要 |
PURPOSE:To prevent the nonuniformity and hardening defect of the resin of the molding taken out of a gypsum mold by coating a compsn. contg. a high polymer binder or high polymer film forming agent, light reflective pigment and a solvent as essential components to a gypsum pattern and drying the coating. CONSTITUTION:The high polymer binder or high polymer film forming agent which is used for the photopolymerizable separating agent is soluble in water, includes synthetic products, such as polyvinyl alcohol and natural products, such as gelatin. The high polymer binder or high polymer film forming agent which is soluble in oil includes thermoplastic synthetic high polymers, such as polyvinyl acetate, and natural products, such as colophonium. While pigments of a white system, such as titanium oxide, are mainly exemplified as the light reflective pigment, the difference in the reflective index regulated by the high polymer binder or high polymer film-forming agent and the solvent is preferably >=0.5. Water, acetone, toluene, etc., may be properly used so as to meet the high polymer binder high polymer film-forming agent as the solvent. The film of this separating agent is easily formed by coating this agent to the gypsum mold and drying the coating. The absorption of light by the color of the gypsum mold is eliminated and the effect of retarding the curing of the resin does not arise and, therefore, the post-hardening by a heat treatment is efficiently executed. |
