| 摘要 |
PURPOSE:To improve the optical transmission and tensile strength, by specifying the blend-ratio, the light transmittance, the Young's modulus, and the tensile strength of a film of a blended polymer mainly consisting of a polyvinilidene fluoride resin and a polymethyl methacrylate resin. CONSTITUTION:A film is made of a blend polymer mainly consisting of a polyvinilidene fluoride resin and a polymethyl methacrylate resin. In this polyvinilidene fluoride type biaxially stretched film, the blend ratio R is 0.05-1.50, the light transmittance thereof at a wave length of 260-700mum is 82% or over, the Young's modulus is 180kg/mm.<2> or over, and the tensile strength is 5kg/mm.<2> or over. The blend polymer is melt-extruded and quenched into an unstretched film having a birefringenece of 2X10<-2> or less, and the film is biaxially stretched 2- 5 times longitudinally and laterally at a stretching temperature of t deg.C that is given by the expression: T<=t<=T+80 wherein T=-24R<2>-18R+82 to produce a polyvinilidene fluoride type biaxially stretched film. This biaxially stretched film is excellent in light transmittance from the ultraviolet region to the visible region and is high in Young' modulus and tensile strength. |
