To provide a biaxially oriented polystyrenic film not only having excellent laminated sheet moldability including laminating processing suitability and even high-speed formability as accuracy of a printing position after lamination but also reducing migration of a styrenic low-molecular weight component to a food, etc., and affording a food packaging container without emitting malodors by reducing the residual amount of the styrenic low-molecular weight component in a film after orienting and suitable for laminating applications.
The biaxially oriented polystyrenic film is obtained by biaxially orienting a resin consisting essentially of a styrenic resin. The film is characterized as follows. The Vicat softening temperature is 103-135°C and the tensile modulus of elasticity is 3-13MPa in both the longitudinal and the transverse directions at 120°C measured according to the ASTM-D882 method. The thermal stress shrinkage stress measured according to the ASTM-D1504 method is 400-2,000kPa in both the longitudinal and the transverse directions. The styrenic low-molecular weight component remaining in the film is 50-3,000ppm.
YASUGATA KOICHI
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