| 摘要 |
PROBLEM TO BE SOLVED: To prevent a thermoplastic resin film put over an external surface of a can lid from getting damaged when a curl of the can lid is doubly seamed around an upper rim of a can barrel by a machining tool. SOLUTION: The can lid 1 is formed of a laminate plate with thermoplastic resin films 12 and 13 such as polyester put over the external surface of an aluminum plate 11. The curl 7 with a curved cross section is formed along the outer periphery of the can lid 1, and the curl 7 is doubly seamed around the upper rim of the can barrel by a winding roll 8. In such a can lid 1, plastic deformation strength due to a load in the axial direction of the can of the curl 7 is specified to be more than 40 N and less than 80 N, so that the curl 7 smoothly follows the deformation along a curve forming surface 8a of the roll 8. COPYRIGHT: (C)2006,JPO&NCIPI
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