| 摘要 |
<p>PURPOSE:To provide a base material for optical card, excellent in heat resistance, surface hardness, transparency, melt formability, scratch resistance and low photoelastic modulus, also giving low birefringence, consisting of an aromatic polycarbonate resin having bis(oxyphenylene)fluorene unit. CONSTITUTION:This base material consists of a polycarbonate resin made up of constituent units of respective formulas I and II (R1-R6 are each H, halogen, etc.; W is single bond, alkylidene, etc.; (m) and (n) are each 1-4) and has 1-40 units of the formula I per 100 constituent units and also has the following characteristics: specific viscosity: 0.19-0.63 determined for a solution prepared by dissolving 0.7g of the resin in 100ml of methylene chloride. This resin can pref. be obtained by interfacial polycondensation of 9,9-bis(4-hydroxyphenyl) fluorene and another dihydric phenol (pref., bisphenol A) with (C) phosgene, or by ester interchange reaction of the components A and B with diphenyl carbonate.</p> |
