| 摘要 |
PROBLEM TO BE SOLVED: To manufacture an optically functional polymer film having a high retardation value and excellent in transparency. SOLUTION: A dope 21 containing a polymer and a solvent is cast on a casting drum 31 of which the surface is cooled to form a cast film 35. After self-supporting properties are imparted to the cast film 35 by cooling and solidifying the cast film 35, the cast film 35 is peeled from the casting drum 31 to be fed to a pin tenter 13 as a wet film 41. A large number of pins are thrust in both side end parts of the wet film 41 in the pin tenter 13 to fix the wet film 41 and this wet film 41 is dried during feed to form a film 20. Next, the film 20 showing predetermined X-ray diffraction intensity is fed into a clip tenter 14 and, during the feed of the film 20 in a state that both side end parts of the film 20 are clipped, the film 20 is stretched in its lateral direction in a stretching magnification of 15-40% to control the molecular orientation of the film 20. By this method, the film 20 suppressed in the lowering of transparency and having a high retardation value can be obtained. COPYRIGHT: (C)2007,JPO&INPIT |
