| 摘要 |
PURPOSE:To improve dispersibility of iron oxide fine magnetic powder by incorporating a binder made of a polyurethane resin made from a compd. contg. an active hydrogen, and polyisocyanate, and a magnetic power specified in particle diameter. CONSTITUTION:A magnetic recording material contains a magnetic powder having a particle diameter of 10-800nm and a binder made of a polyurethane resin made from polyisocyanate, and an active H-contg. compd. composed of polymer polyol having 250-5,000 equivs., a modified silicone oil (A2) having an active H-contg. group, and an active H-contg. polyfunctional compd. having low mol.wt. and 30-200 equivs. As the active H-contg. group of said silicone oil (A2), groups of OH, NH2, NH, and SH are enumerated. A2 has an equivalent (mol.wt. per one active H atom) is usually 100-10,000, preferably, 200-5,000.
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