MAGNETIC RECORDING MEDIUM

摘要

PURPOSE:To obtain a magnetic recording medium having an excellent electromagnetic conversion characteristic and substantial running durability by kneading a thickened soln. of a vinyl chloride/vinyl acetate/vinyl alcohol copolymer and ferromagnetic pulverous powder. CONSTITUTION:A magnetic paint prepd. by mixing a soln. of >=15% concn. of a vinyl chloride/vinyl acetate/vinyl alcohol copolymer contg. 5-15% vinyl alcohol and pulverous ferromagnetic powder in the 1st stage then adding a rubber-base resin soln. and additive to the mixture and dispersing the same in the 2nd stage is coated on a nonmagnetic base. The magnetic paint mixed with a polyisocyanate compd. in the 3rd stage according to need is coated on the nonmagnetic base. If such kneading treatment is performed, the vinyl chloride/vinyl acetate/ vinyl alcohol copolymer contg. the much vinyl alcohol component which is liable to generate problems in runnability and durability in conventional dispersion is usable without any problem.