| 摘要 |
PURPOSE:To improve the dispersibility, wear resistance and heat resistance of magnetic powder, by providing a magnetic layer which contains a specific quad copolymer, epoxy resin and trifunctional low-molecular-weight isocyanate. CONSTITUTION:Into a copolymer of 200-600 polymerization degree consisting of 70-80wt% vinyl chloride, 1-5wt% vinyl acetate, 2-10wt% acrylic ester, and 10-20wt% vinyl alcohol, 5-50wt% epoxy resin of a bisphenol type, novolak type, etc., of 300-2,000 molecular weight is mixed. A binder obtained by adding trifunctional low-molecular weight isocyanate to the said mixture by 3-50wt% to the whole the binder is contained in a magnetic layer to improve the dispersibility of magnetic powder, so that the magnetic recording medium having the magnetic layer superior in wear resistance and heat resistance can be obtained. |
