| 摘要 |
PURPOSE:To obtain excellent magnetic recording material, by using a binder made of polyurethane resin consisting of mixed polyol with specific ratio of specified macromolecular polyol and low molecular polyol including >=3 functional groups, with nonaromatic polyisocyanate. CONSTITUTION:A polyurethane resin C in which the NCO/OH equivalent ratio is 0.6-1.5, can be manufactured by reacting a mixed polyol A including macromolecular polyol A1 of equivalent 200-2,000 having >=50wt% polycaprolacton polyol a1 and low molecular polyol A2 including 1-40 equivalent % of low molecular polyol a2 of >=3 functional groups (trimethylolpropane), with nonaromatic polyisocyanate (isophorone disocyanate). The magnetic substance layer is formed by using this resin C as binder. Thus, the magnetic recording medium excellent in the uniform dispersion property of magnetic powder, smoothness, wear resistance, scrap resistance, and hydrolysis resistance, can be obtd. |
