Abstract
The most widely used agents for separating acrylic resin from gypsum molds are the watersoluble alginates, which produce a very thin water-and organic solvent-insoluble calcium alginate film on the gypsum surface. In the present study, a new type of separating agent, an isocyanate type coating agent, was developed and it's properties were investigated. This coating agent is composed mainly of trimethylol-propane-tolylenediisocyanate and ethyl-acetate, with a small amount of bis-tributyl-tin oxide as catalyst. At first, a thin film was formed on the surface by application of the agent, and then alkyl-phosphate was applied to this film to ensure easy separation of the cured resins from the molds. The molds treated with this separating agent had a glossy, hard surface. The surface of the cured resins treated in this way was glossier and smoother than that of resin treated with the water-soluble alginates.
