Patent ID: 7585576

Claim:
A magnetic recording medium comprising: a non-magnetic supporter; a first magnetic layer formed above said non-magnetic supporter and formed from a magnetic paint having a first ferromagnetic material; and a second magnetic layer formed above said first magnetic layer and formed from a magnetic paint having a second ferromagnetic material, wherein the first magnetic layer and the second magnetic layer include polyester polyol having an alicyclic framework and a polyurethane resin composed of diisocyanate and wherein a concentration of a urethane group in the polyurethane resin ranges from 0.5 mmol/g to 3.0 mmol/g, the first magnetic layer having a thickness approximately five times greater than a thickness of the second magnetic layer and wherein a combined thickness of said first and second magnetic layers is approximately 3.0 μm and further wherein at least one of the first and second magnetic layers includes alkali metal sulfonate incorporated into the resin at concentration of 0.001 mmol per gram to 1.0 mmol per gram, wherein a urethane group concentration for the first magnetic layer and the second magnetic layer is substantially the same, and wherein the first and second magnetic layers are deposited via a Wet-on-Wet method.