| 摘要 |
PURPOSE:To increase the dispersibility of magnetic powder and the heat-resisting property of a magnetic layer, by using simultaneously a specific urethane resin and an isocyanate compound as the component of binder for magnetic layer formation of a magnetic recording medium. CONSTITUTION:(A) an urethane resin having >10,000mol.wt. and hydroxyl group at the end, including a kind of isocyanate component which is selected from isophorone diisocyanate of formulaI, hydrogenated xylene diisocyanate of formula II, hydrogenated tolylene diisocyanate of formula III, and hydrogenated diphenylmethane diisocyanate of formula IV, and (B) isocyanate compound having <=2,000mol.wt. and >=2 isocyanate groups (e.g., tolylene diisocyanate) are mixed in the range of 9:1-5:5 weight ratio. A magnetic layer is formed by using this mixture as a binder to achieve an objective magnetic recording medium. |
