Optical film comprising polyarylates containing bis-(hydroxyphenyl)-fluorene-ortho-disubstituted bisphenols

摘要

The present invention refers to an optical film comprising one or more polyarylates having at least some units represented by the general structure: wherein A represents one or more different bisphenolfluorene radicals having the general formula (I): wherein R1 and R2 independently represent an alkyl group, a halogen, an alkoxy group, an acyl group, a phenyl group or a nitrile group, with the proviso that R1 and R2 are not both an alkyl group; R3, R4, R5 and R6 represent a hydrogen atom, an alkyl group, a halogen, an alkoxy group, an acyl group, a phenyl group, a nitro group, or a nitrile group; B represents one or more different dicarboxy radicals having the formula: wherein X is a divalent hydrocarbon group having from 1 to 20 carbon atoms, and n is the number of the repeating units which build up the polymer and is a positive integer higher than 20. The optical film of the present invention has excellent mechanical and thermal properties, a high Tg and does not readily yellow upon exposure to light.