Polyester film with smooth and highly adhesive surface and method of making same
AssigneeToray Industries, Inc.
InventorsKenji Hatada, Ken-ichi Kawakami, Hiroaki Kobayashi
Life of this patent
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Abstract
Disclosed is a biaxially stretched polyester film having a modified surface with an excellent bondability, in which both the surface smoothness and the slip characteristic, which are contradictory to each other, are satisfactory. This biaxially stretched polyester film has a multiplicity of ultra-fine protrusions which are an integral part of the film and dyeable with osmic acid. The film is prepared by subjecting an undrawn or drawn polyester sheet to a plasma treatment and then drawing the treated sheet at least once. The film is valuable as a base for a magnetic recording medium.
Claims12
A biaxially stretched polyester film having a multiplicity of elongated and directionally arranged ultra-fine protrusions on the surface thereof, wherein said protrusions have a height of 50 to 300 angstroms and a width of 100 to 300 angstroms and 1 to 20 protrusions are present per .mu.m of the surface length as observed on a cross-section perpendicular to the direction of the arrangement of the protrusions, said protrusions being an integral part of the polyester film and tightly adherent thereto and being dyeable with osmic acid, and said film having a static friction coefficient (.mu.s) of 0.3 to 3.0.
A magnetic recording medium comprising a magnetic layer laminted at least on a part of biaxially stretched polyester film having a multiplicity of elongated and directionally arranged ultra-fine protrusions on the surface thereof, wherein said protrusions have a height of 50 to 300 angstroms and a width of 100 to 3000 angstroms and 1 to 20 protrusions are present per m of the surface length as observed on a cross-section perpendicular to the direction of the arrangement of the protrusions, said protrusions being an integral part of the polyester film and tightly adherent thereto and being dyeable with osmic acid, and said film having a static friction coefficient (.mu.s) of 0.3 to 3.0.
Dependencies are inferred from the claim text.