MAGNETIC RECORDING MEDIUM COMPRISING A POLYURETHANE BINDER RESIN HAVING A SPECIFIED GLASS TRANSITION, MOLECULAR WEIGHT, AND POLAR GROUP CONTENT

摘要

A magnetic recording medium is disclosed which has a magnetic layer comprising a ferromagnetic powder and a specific polyurethane resin as a binder. The polyurethane resin has a weight average molecular weight of not more than 30,000, a glass transition point of not higher than 0 DEG C. and a -SO3M group, wherein M is a hydrogen atom or an alkali metal atom, in an amount of not less than 0.35% by weight in terms of sulfur atom. The recording medium is excellent in the dispersibility of the magnetic powder in the binder and has high running stability.