Polyurethane resin binder for magnetic recording mediums comprising a polycarbonate polyol

摘要

A binder for a magnetic recording medium comprising a hydroxy-group-terminated polyurethane resin prepared by reaction of a polycarbonate-polyol, a chain-extender, and an organic diisocyanate; (A) said polycarbonate-polyol comprising poly(cyclohexane-1,4-dimethanol carbonate)-polyol as a constituting component in an amount of from 20 to 80% by weight, and (B) said chain-extender being a compound having a molecular weight of not more than 1,000 and having two or more amino or hydroxyl groups in the molecule.