Patent ID: 6074724
Filing Date: 2000-06-13
Classification: B82Y,G11B,Y10S,Y10T

Abstract:
A magnetic recording medium comprising a support having thereon, in succession, an undercoating layer comprising a binder U and an inorganic powder and a magnetic layer comprising a binder M and a ferromagnetic metal powder, wherein said binder M comprises a polyurethane resin which is produced by reacting diols with an organic diisocyanate; said diols comprise a first diol having at least one cyclic hydrocarbon group and a molecular weight of from 50 to less than 500 and a second diol having at least one ether linkage and an average molecular weight of 700 to 3,000; and said first diol is contained in a proportion of from 17 to 40 weight % and said second diol is contained in a proportion of from 10 to 50 weight %, based on said polyurethane resin; and further said ether linkage in said second diol are contained in a content of from 1.0 to 5.0 mmol/g, in terms of said ether linkage based on said polyurethane resin; and wherein said ferromagnetic metal powder comprises Fe, from 10 to 40 atomic % of Co, from 2 to 20 atomic % of Al and from 1 to 15 atomic % of Y, based on said Fe; and has a mean major axis length of from 0.05 to 0.19 and a crystallite size of from 100 to 230 angstrom.