| 摘要 |
PURPOSE:To obtain a molding with favorable surface condition having no sink mark by a method wherein a sheet is held on one surface in a mold at reaction injection molding. CONSTITUTION:A sheet is held on one surface in a mold at reaction injection molding. For example, a sheet is fixed softly on one surface in the mold 1 by applying double-sided adhesive tapes at several positions. Or one end of the sheet 2 is pinched between a top and a bottom forces 1 and 1. Or a force to which the sheet 2 is set is placed down. A sheet which neither melts by molding material nor deforms due to the heat generating during polymerization and hardening reaction is favorable. Especially, a Teflon sheet gives favorable effects regardless of the kind of molding material. When molding material is poured in a high-temperature mold, the material quickly polymerizes and hardens itself in the solid form and shrinks. When the sheet is held on one surface of the mold, the sheet tightly joins onto the surface of a molding and slides together with the cure shrinkage of the material, resulting in preventing sink mark followed by the shrinkage from developing. |
