| 摘要 |
PURPOSE:To obtain a binder for magnetic recording materials, having excellent dispersibility of magnetic materials, adhesivity to substrates, calendering property, etc., and suitable for video tapes, magnetic cards, etc., by reacting a specific polyol with an organic polyisocyanate. CONSTITUTION:(A) A polyol, consisting of (i) a high polymer polyol having 200-2,000 equivalent, e.g. polycaprolactone polyol, etc., (ii) a low-molecular polyol, e.g. ethylene glycol, etc., (iii) a carboxyl group-containing urethane- modified diol, prepared by reacting dimethylolpropionic acid with tolylene diisocyanate and containing 0.1-60 equiv.% component (iii) and 10-50 equiv.% component (ii) is blended with (B) an organic polyisocyanate, e.g. xylylene diisocyanate, etc., and a magnetic substance, e.g. iron oxide, etc., is blended therewith. A solvent, if desired, is added and the resultant blend is applied to a substrate to afford the aimed binder.
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