| 摘要 |
PROBLEM TO BE SOLVED: To provide rolled copper foil not only having excellent bending resistance, but also having extremely reduced deterioration in strength even if being stored at room temperature over a long period, and suitable for a flexible printed circuit (FPC). SOLUTION: The rolled copper foil comprises, by weight,≥99.9% copper, 0.0001 to 0.015%, desirably, 0.0001 to 0.001% oxygen, and the balance inevitable impurities. In the cross-sectional structure of the copper foil 1 annealed after final rolling, the cross-sectional area ratio of the crystal grains 2 penetrated the copper foil 1 in a sheet thickness direction is≥40%. The rolled copper foil has high initial tensile strength, and its tensile strength after being left at 30°C for a year is≥350 MPa. COPYRIGHT: (C)2008,JPO&INPIT
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