SEAMLESS CAN AND MANUFACTURE THEREOF

摘要

PROBLEM TO BE SOLVED: To improve the impact resistance and the corrosion resistance after a formed can for which a printing and a secondary process have been applied by a method wherein a plurality of oriented crystalization states being shown by specified endothermic peaks in a differential thermal analysis, are imparted to a polyester layer on the internal surface of the can, and a spontaneous stretching property is imparted to a polyester layer straight under the flange part. SOLUTION: A laminate plate 1 wherein at least on the internal surface of a metal plate 2, a biaxially oriented polyester film 3 is laminated by a condition to remain the biaxial orientation, is draw-iron-molded, and is formed into a can body wherein the polyester layer 3 is uniaxially oriented, and a heat treatment is performed by a temperature which is -60 to -5 deg.C of the melting point of the polyester. Then, a printing is applied on the external surface of the can body with an ultra-violet ray hardening type ink, and the ink is hardened by irradiating ultra-voilet rays. Then, the printed can body is secondarily molded, and a post-heat treatment is performed by a temperature which is +100 to 150 deg.C of the glass transition point of the polyester. By this method, three kinds of oriented-crystalization states corresponding with specified three endothermic peaks in a differential thermal analysis, and internally distorted state are realized on the polyester layer 3.