Patent ID: 6068909
Filing Date: 2000-05-30
Classification: B32B,G11B,Y10S,Y10T

Abstract:
A biaxially oriented laminated polyester film comprising a first layer of an aromatic polyester containing inert fine particles having an average particle diameter of 1.0 .mu.m or less in an amount of 0.01 to 2% by weight and a second layer of an aromatic polyester, having a thickness of 2 to 8 .mu.m, wherein:(a) the ratio (t/d) of the thickness t (.mu.m) of the first layer to the average particle diameter d (.mu.m) of the inert fine particles is 5 to 30;(b) the exposed surface of the first layer has a dynamic friction coefficient (.mu.k.sub.1) against a metal of 0.15 to 0.50, and the exposed surface of the second layer has a dynamic friction coefficient (.mu.k.sub.2) against a metal of 0.24 to 0.60, and the ratio .mu.k.sub.2 /.mu.k.sub.1 is 1.2 to 4.0; and(c) the film has a Young's modulus of 400 to 2,000 kg/mm.sup.2 in both the longitudinal and transverse directions.