Magnetic recording medium having specific subbing layers and process for recovery and processing thereof

摘要

A magnetic recording medium comprising a subbing layer provided between a nonmagnetic plastic support and at least one of a magnetic layer and a backing layer, the magnetic layer and the backing layer each having a void of 40% by volume or less, and the subbing layer having higher solubility in a 0.5 wt % alkaline aqueous solution at 40 DEG C. than that in water at 40 DEG C. and being soluble in a weak alkaline aqueous solution having an initial pH of less than 13 or a low concentration alkaline aqueous solution having 0.25N or less. The subbing layer comprising a polymer containing acidic polar groups, and the subbing layer being soluble in a weak alkaline aqueous solution having an initial pH of less than 13 or a low concentration alkaline aqueous solution having 0.25N or less. A process for recovery and processing of a magnetic recording medium, the process comprising the steps of: (1) cutting a magnetic recording medium comprising a nonmagnetic plastic support having thereon a magnetic layer and/or a backing layer each having a void of 40% by volume or less; (2) dipping pieces of the magnetic recording medium in a weak alkali having an initial pH of less than 13 or a low concentration alkaline aqueous solution having 0.25N or less with stirring so that a subbing layer in the pieces having higher solubility in an alkaline aqueous solution than that in water is dissolved therein to peel off the magnetic layer and/or the backing layer from the nonmagnetic plastic support, and (3) separating the magnetic layer and/or the backing layer from the nonmagnetic plastic support.