| 摘要 |
PURPOSE:To obtain a 1/4 wavelength film with superior film formability, transparency, water resistance, heat resistance, etc. by orienting a styrene polymer film or sheet so as to adjust the retardation value measured with a polarization microscope to a specified range. CONSTITUTION:A homopolymer, a copolymer, a polymer blend, etc. of styrene and its deriv. are dissolved preferably in a solvent and formed into an about 10-500mu film or sheet by a casting method. This film or sheet is then subjected to uniaxial orientation by a free or fixed width, biaxial orientation or other orientation so as to adjust retardation value R represented by the equation and measured with a polarization microscope to 95-170nm. Thus, a 1/4 wavelength film capable of converting linearly polarized light and circularly polarized light is obtd. This film has enhanced clear cuttability, strength, etc. |
