Patent ID: 8268215

Claim:
A method for producing a laminated film, which comprises providing an unstretched laminated film which comprises at least two layers one of which is a surface layer comprising an aromatic polyester which comprises substantially no antimony element in an amount of 20 ppm or lower and the other layer other than the surface layer comprises an aromatic polyester containing 31 to 80 wt. % of inert particles having an average particle diameter of 0.3 to 3.0 μm; stretching the unstretched laminated film in the longitudinal direction and then in the transverse direction; heat-treating the obtained stretched laminated film with both ends of the film held; cutting off the held ends of the heat-set film while the film is allowed to cool to room temperature and subjecting the film to relaxation in the longitudinal direction at a relaxation ratio of 0.1 to 1.5% and a relaxation temperature of 115° C. to 150° C., wherein the laminated film is a laminated film for a reflecting plate, which comprises at least two layers one of which is a surface layer comprising an aromatic polyester which comprises substantially no antimony element in an amount of 20 ppm or lower and the other layer other than the surface layer comprises an aromatic polyester containing 31 to 80 wt % of inert particles having an average particle diameter of 0.3 to 3.0 μm, wherein said laminated film has heat shrinkages at 85° C. in the two directions of longitudinal direction and transverse direction perpendicular to each other of 0.7% or less.