| 摘要 |
PROBLEM TO BE SOLVED: To provide a film with a high glass-transition temperature, high transparency, low birefringenece, a low water absorption coefficient and sufficient toughness, and polybenzoxazoles available to make the film, and others. SOLUTION: The polybezoxazole has a repeated unit shown by formula (1) (wherein R represents a bivalent alicyclic ring group) with cutoff wavelengths of 300 nm or less in a film of 20μm thickness and a transmittance of 70% or over at 400 nm. COPYRIGHT: (C)2006,JPO&NCIPI |
