| 摘要 |
PURPOSE:To improve the electromagnetic conversion characteristic and running durability of a recording medium by radiating radiations to a magnetic layer contg. >=1 kinds of a specific PVC compd. and polyurethane compd. and polishing agent. CONSTITUTION:The following binder and the polishing agent (e.g.: alpha-Al2O3) having 0.1-1.0 average primary particle size and >=6 Mohs' hardness are incorporated into the magnetic layer contg. pulverized ferromagnetic powder, more preferably ferromagnetic alloy powder having >=30m/g BET specific surface area and further are irradiated with the radiations: The binder includes (A) the compd. (e.g.: vinyl chloride compolymer acrylate) which contains respectively >=1 polar groups and carbon-carbon unsatd. bonds within the molecule and has 1-30 acid value when the polar groups are a CO2H group, and (B) the polyurethane compd. contg. respectively>=1 CO2H groups and carbon-carbon unsatd. bonds within the molecule, more preferably polyurethan (meth)acrylate. >=1 Kinds of A and B are incorporated into the binder.
|
