| 摘要 |
PROBLEM TO BE SOLVED: To provide a binder which is excellent in dispersibility of magnetic powder, keeps a mechanical strength of a magnetic tape, hardly causes peeling, breakage and the like of the magnetic tape, and is excellent in durability.SOLUTION: A binder for a magnetic recording medium contains a polyurethane resin (C) obtained by reacting an active hydrogen component (A) and a polyisocyanate component (B). The active hydrogen component (A) contains an active hydrogen compound (a1) which is an active hydrogen compound (a11) represented by general formula (1): [H-(OA)]NSOXand/or an active hydrogen compound (a12) represented by general formula (2): [H-(OA)]NSOX; a polymer polyol (a2); and a low molecular polyol (a3). In the formulae, OAand OArepresent oxyalkylene groups having 2 to 4 carbon atoms; m and n represent integers of 2 to 13; Xrepresents a hydrogen atom; and Xrepresents an alkali metal ion, NH, organic ammonium or quaternary ammonium.SELECTED DRAWING: None |
