Magnetic recording medium

Claim 1

A magnetic recording medium comprising finely divided magnetic metal oxide particles dispersed in a thermosetting resin binder composition and in the form of a thin layer film having a thickness of less than 5 microns closely adhered to a non-magnetic substrate, said thermosetting resin binder composition comprising: a. 30% to 95% by weight of a copolymer consisting essentially, based on the weight of the copolymer, of 1. 25% to 65% by weight of units derived from at least one compound selected from the group consisting of alkyl acrylate and alkyl methacrylate, the alkyl group having 1 to 4 carbon atoms, 2. 3% to 30% by weight of units derived from at least one compound selected from the group consisting of N-methylolacrylamide and N-alkoxymethylacrylamide, the alkoxy group having 1 to 4 carbon atoms, 3. 10% to 60% by weight of units derived from at least one compound selected from styrene and methyl styrenes, and, 4. 0% to 30% by weight of units derived from at least one other copolymerizable ethylenically unsaturated compound, and; b. 5% to 70% by weight of an epoxy resin, the predominant constituent being a condensation product of bisphenol A and epihalohydrin, possessing an average molecular weight of approximately 300 to approximately 2,000.