MAGNETIC DISK SUBSTRATE AND MAGNETIC RECORDING MEDIUM USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a plastic magnetic disk substrate which is minimized in bending, reduced in straightness and flatness and has excellent floating characteristics of head, and a magnetic recording medium using this substrate. SOLUTION: This magnetic disk substrate is formed by injection molding of a thermoplastic resin and the density (n) of the magnetic disk substrate and the Young's modulus E of its thermoplastic resin satisfy the relation n/E<=4.5×10<-4> ((g/cm<3> )/MPa).