| 摘要 |
PURPOSE:To obtain the optical resin material which allows exact recording and reproducing with the decrease in optical distortions and is excellent in transparency as well by using a specific thermoplastic arom. polyester as an essential component. CONSTITUTION:The molar fraction (a) of the residual group of the 2, 2'-biphenol deriv. occupying the residual group component of the total diol in a polymer and the molar fraction (b) of the residual group of the diphenic acid deriv. occupying in the residual group component of the total dicarboxylic acid deriv. in the polymer satisfy the relations expressed by formula I. The adjacent phenyl rings intersect orthogonally with each other owing to the steric hindrance of the 2, 2' positions and do not orient on the same plane in the biphenyl skeleton of the 2, 2'-biphenol and diphenic acid unit, therefore, the optical anisotropy of the phenyl rings is offset in the molecules and the optical distortions are decreased. The high transparency eliminated by using the 2, 2'-biphenol and diphenic acid unit having no orientability is obtd. The optical resin material which allows exact recording and reproducing and has the excellent transparency when used, for example, as an optical disk substrate material is obtd. in this way. |
