MOLD MATERIAL

摘要

PURPOSE:To uniformize a formed and crystallized calcium phosphate glass and to prevent the generation of defects such as bubbles in the glass, by placing calcium metaphosphate crystal on the surface of a mold material to be contacting with the forming material. CONSTITUTION:A calcium phosphate glass is formed and crystallized in a mold having calcium metaphosphate crystal on a mold surface to be contacted with the phosphate glass. The amount of calcium metaphosphate is about >=10wt% and the depth of the calcium metaphosphate layer is about >=10mu from the surface. A homogeneous and semi-transparent glass free from defects such as bubbles can be formed by the use of the mold. The mold can be produced either by mixing a mold material with calcium metaphosphate crystal and hardening the mixture on a mold or by mixing calcium metaphosphate crystal to a base material and applying the mixture to the surface of a mold produced beforehand.