Back to results
US 6,203,883 B1Granted
Biaxially oriented laminated polyester film for magnetic recording medium
AssigneeTeijin Limited
InventorsTatsuya Ogawa, Hideaki Watanabe
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeTeijin Limited
InventorsTatsuya Ogawa, Hideaki Watanabe
Estimating the term…
The film of the present invention is a biaxially oriented laminated polyester film for magnetic recording medium consisting of a polyester layer A containing fine particles and laminated to at least one surface of a polyester layer B, wherein the fine particles in the polyester layer A are composed of 0.001 to 0.03% by weight of crosslinked polymer particles (a) having an average particle diameter (da) of 0.9 to 1.6 μm, 0.1 to 0.8% by weight of inert particles (b) having an average particle diameter (db) of 0.4 to 0.8 μm and 0.05 to 1.0% by weight of inert inorganic particles (c) having an average particle diameter (dc) of 0.01 to 0.3 μm and a Mohs hardness of 7 or above, and the ratio of the thickness TA (μm) of the polyester layer A to the average particle diameter da (μm) of the crosslinked polymer particle (TA/da) is in the range of from 0.4 to 2.0. The film has excellent windability, abrasion resistance, transportation durability and electromagnetic conversion characteristics and is producible at a low production cost and useful especially as a base film of a magnetic recording medium for high-speed duplicator.
A biaxially oriented laminated polyester film for magnetic recording medium, the biaxially oriented laminated polyester film comprising a polyester layer A containing fine particles on at least one surface of a polyester layer B, wherein the fine particles in the polyester layer A are composed of 0.001 to 0.03% by weight of crosslinked polymer particles (a) having an average particle diameter (da) of 0.9 to 1.6 μm, 0.1 to 0.8% by weight of inert particles (b) having an average particle diameter (db) of 0.4 to 0.8 μm and 0.05 to 1.0% by weight of inert inorganic particles (c) having an average particle diameter (dc) of 0.01 to 0.3 μm and a Mohs hardness of 7 or above, wherein the ratio of the thickness TA (μm) of the polyester layer A to the average particle diameter da (μm) of the crosslinked polymer particle (TA/da) is in the range of from 0.4 to 2.0, the center line average roughness RaA on the surface of the polyester layer A is from 8 to 18 nm, and the windability index of the polyester film is 100 or lower at a take-up speed of 200 m/min.
Dependencies are inferred from the claim text.