| 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, acryl nitrilebutadiene copolymer and trifunctional low-molecular weight isocyanate. CONSTITUTION:A magnetic layer is formed by using a binder which contains a copolymer of 200-600 polymerization degree consisting of 70-80wt% vinyl chloride, 1-5wt% vinyl acetate, 2-10wt% acrylic ester, 10-20wt% and vinyl alcohol, by combined use of an acryl nitrile-butadiene copolymer of <10,000 molecular weight by 5-40wt% based on the said copolymer and that of >=10,000 by 5-80wt%, and further, trifunctional low-molecular weight isocyanate by 3-50wt% based on the total amount of the binder is used to form a magnetic layer. |
