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

Abstract

The present invention refers to a polymeric optical film the polymer of the polymeric optical film consisting essentially of one or more polyarylates having repeating units represented by the general structure:wherein A represents one or more different bisphenolfluorene radicals having the general formula (I):wherein Rand Rindependently represent an alkyl group, a halogen atom, an alkoxy group, an acyl group, a phenyl group or a nitrile group, with the proviso that Rand Rare not both an alkyl group; R, R, Rand Rrepresent a hydrogen atom, an alkyl group, a halogen, an alkoxy group, an acyl group, a phenyl group, a nitro group, or a nitrile group, with the proviso that when Rand Rare both bromide atoms, at least one of R, R, Rand Ris different from hydrogen atom;B represents one or more different dicarboxy radicals having the formula:wherein X is a divalent aromatic hydrocarbon group having from 6 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.