| 摘要 |
PROBLEM TO BE SOLVED: To prevent dew condensation and to obtain a consumer digital video tape excellent in electromagnetic conversion characteristics and durability by forming a ferromagnetic metal thin film having specified surface roughness and recesses of a specified size on one surface of a polyester film. SOLUTION: A high strength film is prepared by incorporating >=80% polyethylene terephthalate or polyethylene-2,6-naphthalate and by orientation of molecules, and a metal thin film layer containing specified ferromagnetic fine particles is formed on one surface of the film. The center line roughness (SRa) of the metal thin film layer is controlled to 2 to 5nm to balance the wearing property and output characteristics, and the ten-point average surface roughness SRz of the layer is controlled to 10 to 50nm, to maintain the durability of the magnetic film. By forming recesses each having 0.5 to 5μm diameter and 1 to 50nm depth by 1×10<2> to 1×10<5> recesses/mm<2> on the surface, sticking of the video tape to a drum due to dew condensation can be prevented and the contact state between the tape and a head can be maintained in a good state.
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