| 摘要 |
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 mum, 0.1 to 0.8% by weight of inert particles (b) having an average particle diameter (db) of 0.4 to 0.8 mum 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 mum and a Mohs hardness of 7 or above, and the ratio of the thickness TA (mum) of the polyester layer A to the average particle diameter da (mum) 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.
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