POLYESTER FILM FOR COATING METAL SHEET, POLYESTER FILM COATED METAL SHEET AND POLYESTER FILM COATED METAL CONTAINER

摘要

PROBLEM TO BE SOLVED: To provide a polyester film for coating a metal sheet not producing the shaving refuse of the film at the time of seaming processing and not containing Sb having a control value, a polyester film coated metal sheet excellent in can making processability and a polyester film coated metal container excellent in corrosion resistance and the protectivity of food becoming content. SOLUTION: The polyester film has a two-layered constitution of layer A/layer B wherein the layer A comprises a polyester resin with a melting point Tma of 240-260°C and an intrinsic viscosity IVa of 0.55-0.75 and the layer B comprises a polyester resin with a melting point Tmb of 220-235°C and an intrinsic viscosity IVb of 0.55-0.75. The maximum values of shrinkage stress in the flow direction and width direction of the polyester film when the polyester film is measured by a thermomechanical analyzer (TMA) are 1.2-3.0 MPa. Each of the maximum values of shrinkage stress satisfies the formula: Fx >Fy (wherein Fx is the maximum value of the shrinkage stress in the flow direction of the film and Fy is the maximum value of the shrinkage stress in the width direction of the film). This polyester film contains no Sb element substantially. COPYRIGHT: (C)2005,JPO&NCIPI