| 摘要 |
PURPOSE:To obtain the lens which has high surface accuracy and excellent optical characteristics, is light in weight and is highly resistant to impact by subjecting a mixture which is composed of polyisocyanates and specific active hydrogen compds. and is added with an internal release agent to cast polymn. CONSTITUTION:The plastic lens having a high refractive index is produced by adding the internal release agent to the mixture composed of 1 or >=2 kinds of the polyisocyanates and 1 or >=2 kinds of the active hydrogen compds. selected from a group consisting of polyol and polythiol contg. at least one sulfur atom except a mercapto group and subjecting the mixture to the cast polymn. For example, ethylene diisocyanate, trimethylene diisocyanate, etc., are used as the polyisocyanate. |
