| 摘要 |
PURPOSE:To obtain a recording medium having an excellent electromagnetic conversion characteristic and high durability by incorporating magnetic powder and lubricating agent into a binder prepd. by adding polyisocyanate to a mixture composed of a polyurethane resin having 100% modulus within a specific value range and nitrocellulose at a specific compounding ratio. CONSTITUTION:The magnetic paint formed by mixing thoroughly the compd. consisting of a polyurethane resin having 50-100kg/cm<2> 100% modulus and nitrocellulose at 60:40-90:10 wt. ratio, a lubricating agent and magnetic powder as well as necessary additives such as a dispersion assistant, carbon black and an org. solvent then adding polyisocyanate to the mixture is prepd. Such paint is coated on a base and is dried then the surface is finished to a specular surface by calender rolling. The compsn. consisting of higher fatty acid : aliphat. dibasic acid ester at 40:60-60:40 ratio by weight is preferred for the lubricating agent. Sticking of the lubricating agent to the roll surface is thus obviated and the magnetic recording medium having good dispersibility of the magnetic powder, an excellent traveling characteristic and wear resistance, mechanical characteristics, etc. of the magnetic layer is obtd. |
