| 摘要 |
PROBLEM TO BE SOLVED: To prevent production of wrinkles or deposition of dust and to obtain good cupping and stable travelling of a film having a back coating layer by specifying the surface electric resistances of the film where the back coating layer is not formed and of the back coating layer. SOLUTION: The surface resistance of the film where the back coating layer is not formed is controlled to <=5×10<12>Ω, while the surface electric resistance of the back coating layer is controlled to <=5×10<6>Ω. After forming the back coating layer on the back surface of a film having <=9μm thickness and >=1×10<13>Ωsurface resistance, a magnetic layer is formed on the surface of the film. Then before slitting, the film is preferably subjected to pretreatment at a higher temp. than the temp. of a drying furnace in the process of forming the magnetic layer. As for the film, polyesters, polyolefins, cellulose derivs., vinyl resin or ceramics are used. The thickness of the back coating layer is preferably controlled to 0.03 to 0.15 time as that of the magnetic recording medium, and the layer is formed by applying a back coating material.
|
