| 摘要 |
PROBLEM TO BE SOLVED: To produce a biaxially stretched surface-roughened film composed of a resin compsn. wherein an amorphous polyamide resin is compounded with a thermoplastic polyester resin and having high surface haze and high strength, with good operability. SOLUTION: A mixture of 85-92 wt.% of a thermoplastic polyester resin A and 15-8 wt.% of an amorphous polyamide resin B having glass transition temp. higher than that of the resin A, having critical surface tension different from that of the resin A by 0.1 dyn/cm or more and having melt viscosity at 280 deg.C and a shearing speed of 10<-2> sec<-1> of 500-50000 poise is melted to be formed into an unstretched film and this film is stretched longitudinally and laterally successively to produce a biaxially stretched film. In this sequential biaxially stretched film producing method, longitudinal stretching is performed so that the double refractive index of the film after longitudinal stretching becomes 120×10<-3> -150×10<-3> and, next, lateral stretching is performed under a condition of temp. 90-150 deg.C and lateral stretching magnification of 3.0-4.0 times. |
