Patent ID: 7531252
Filing Date: 2009-05-12
Classification: G11B,H05K,Y10T

Abstract:
1. A magnetic recording medium comprising a magnetic layer on at least one surface of a film formed from an aromatic polyamide, the film being characterized in that the heat shrinkage ratio in the transverse direction of the film subjected to heat treatment under a condition of no tension for 30 mm. at 180° C. is from 1.0 to 2.5%, and wherein the film: (1) satisfies the following equations (1)-(4) simultaneously, with αMD (×10 (2) satisfies the following equations (5) and (6) simultaneously, with EMD (GPa) and ETD (GPa) being Young's moduli in the longitudinal and the transverse direction, respectively, and wherein the magnetic-recording medium satisfies the following equations (7)-(10) simultaneously, with α′MD (×10 −6 /° C.) and α′TD (×10 −6 /° C.) being coefficients of thermal expansion in the longitudinal and the transverse directions, respectively, and β′MD (×10 −6 /% RH) and β′TD (×10 −6 /% RH) being coefficients of hygroscopic expansion in the longitudinal and the transverse directions, respectively,