PRODUCTION OF MAGNETIC RECORDING MEDIUM

摘要

PURPOSE:To obtain a magnetic recording medium with which the expansion and contraction of the medium are small and which has excellent durability and weatherability by forming a magnetic recording layer on a nonmagnetic substrate and subjecting said layer to a curing treatment by heating then to quick cooling. CONSTITUTION:A biaxially oriented polyester film is used as the nonmagnetic substrate and a magnetic coating liquid is prepd. by mixing and dispersing Co-r-Fe2O3 and binder resin as well as additives to be added at need and solvent. The magnetic coating liquid is coated on the nonmagnetic substrate and the coating is oriented and dried to form the magnetic recording layer on one face of the above-mentioned substrate. The magnetic recording layer is subjected to the surface working treatment by a super calender and is taken up to a roll shape. The jambo roll is then thrown into a thermostatic chamber and is subjected to the resting treatment by heating to relieve the internal stress of the medium. The roll is immediately thrown into a cold-temp. chamber kept at -10 deg.C and is quickly cooled. The jambo roll is thereafter taken out of the low-temp. chamber and is restored to the ordinary temp.