Biaxially oriented film and a manufacturing method thereof, a polarizer protective film, decorative film, and a laminated film

The present invention provides a method for producing a biaxially oriented film having thermal contraction and excellent small dimensional stability. The unstretched thermoplastic resin film comprising a thermoplastic resin layer of at least one layer and biaxially stretched in the longitudinal direction and the width direction to produce a biaxially oriented film. Method for producing a biaxially oriented film of the present invention, the step (I) preheating the thermoplastic resin film to a temperature of the rubber-like flat regions in storage modulus curve, a thermoplastic resin film of the rubbery plateau region while heating to a temperature, a step (II) of the biaxially stretched under the conditions described above stretching rate of 500% / min, step (II) after the thermoplastic resin film glass in the storage modulus curve - rubber transition region or glass and a step of relaxing at a temperature of rubber transition region (IV) - and the step (III) to cool to a temperature in the region, step (III) after the thermoplastic resin film and glass.