| 摘要 |
PURPOSE:To easily evaluate the strength of a coated film by immersing a nonmagnetic base on which a magnetic layer prepd. by dispersing magnetic powder into a binder resin is coated into a halogenated hydrocarbon, ether or ketone solvent and measuring the amt. of the eluted resin component. CONSTITUTION:The magnetic layer consisting of a composite material is coated on the front face of, for example, a PET film having 10mum thickness to form an 8-mm magnetic tape. This tape is cut off by a required length. The back coating layer is removed therefrom by tetrahydrofuran, etc., and the tape is put into a vessel in which the halogenated hydrocarbon, ether or ketone solvent is filled; thereafter, the vessel is hermetically sealed and is ultrasonically cleaned under application of the ultrasonic oscillation thereto for 30min to elute the resin component. The tape is taken out of the vessel and the soln. is subjected to centrifugal sepn. The supernatant liquid is put into an aluminum cup which is previously measured of the weight. The liquid is evaporated to dryness over a water bath and the weight of the residue is measured. The residue is then analyzed by using an FT-IR.
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