| 摘要 |
PURPOSE:To improve the dispersibility, wear resistance and heat resistance of magnetic powder by providing a magnetic layer which contains a vinyl chloride-vinyl acetate acrylic ester vinyl alcohol copolymer or/and trifunctional low-molecular weight isocyanate. CONSTITUTION:The dispersibility and output characteristics of magnetic powder are improved by using a magnetic layer having as a binder a copolymer of 200- 600 polymerization degree with composition of 70-80wt% vinyl chloride, 1-5wt% vinyl acetate, 2-10wt% acrylic ester, and 10-20wt% vinyl alcohol. Then, 3- 50wt% trifunctional low-molecular weight isocyanate, obtained by a reaction between 1mol triol and 3mol diisocyanate, is added to the said copolymer to obtain a binder, which is used for the magnetic powder. Thus, the dispersibility, wear resistance and heat resistance of the magnetic powder are improved and output fluctuations are reduced. |
