MANUFACTURE OF ODD-SHAPED CAST ARTICLE

摘要

PURPOSE:To obtain a cast molded article having no sink, by making use of a cast satisfying either a thermal proprty that heat capacity per unit area of a sleeve part of the cast is larger than that of a base part of the cast or one that the quotient obtained by dividing thermal conductivity of the base part by the thickness of the same is larger than that obtained similarly in relation to the sleeve part. CONSTITUTION:A case whose heat capacity per unit area of a sleeve part of the same is larger than that of a base part by 0.3-3cal/ deg.C per 1cm<2> of the external surface of the cast is desirable, in the cast manufacturing a cast molded article by polymerizing and curing a polymerizable monomer or unsaturated polyester resin having methyl methacrylate for its main ingredient within the cast. When a difference of heat capacity per 1cm<2> of the external surface is less than 0.3cal/ deg.C, probability of generation of a sink is high and the contrary even if the same becomes larger than 3cal/ deg.C, leworing of the probability of the generation of the sink more than that can not be expected and a matter that polymeriznig and curing time becomes long or the sleeve part becomes deffective curing is increased in number. Similarly, it is desirable that the quotient obtained by dividing thermal conductivity of the base part by a thickness of the same is larger than that obtained similarly in relation on the sleeve part by more than 0.1cal/cm<2>.sec. deg.C.