| 摘要 |
<p>PURPOSE:To obtain the film adequate as a base film for floppy disks by determining the coefft. of temp. expansion in a film plane and the shrinkage rate under prescribed temp. and humidity conditions at prescribed values and simultaneously satisfying various prescribed conditions. CONSTITUTION:This biaxially oriented polyester film has (1.0+ or -0.5)X10<-5>/ deg.C coefft. alpha of temp. expansion within the film plane and <=0.09% shrinkage rate of the film after the treatment for 72 hours in all directions within the film plane under the temp. and humidity conditions of 60 deg.C and 80% RH and simultaneously satisfies equation I to equation V. In the formulas, nalpha: the refractive index in the thickness direction of the film, DELTAP: plane orientation coefft. n with an overbar; average refractive index: X100: (100) face crystal size(Angstrom ), beta: density. The film is particularly adequate as the base film for the high-density floppy disks.</p> |
