| 摘要 |
PURPOSE:To obtain the titled medium which is not deteriorated in properties even when exposed to a high temp. by specifying the characteristics in an arbitrary direction parallel with a film plane to prescribed values and specifying the center line average height of at least one surface and the thickness of the film to prescribed values and compsn. CONSTITUTION:This magnetic recording medium is constituted by forming a magnetic layer on the film which consists of poly-P-phenylene terephthalamide and has >=1,000kg/mm<2> Young's modulus in the arbitrary direction parallel with the film plane, >=10% elongation, <=3X10<-5>mm/mm/%RH coefft. of hygroscopic expansion, <=0.02% shrinkage on heating at 250 deg.C, <=0.05mum center line average height Ra of at least one surface and <=8mum thickness. The material of this film is a kind of arom. polyamide and is the polymer expressed by formula I. Said film has high crystallinity, high orientational property, dense structure, heat resistance and high dimensional stability. |
