| 摘要 |
PURPOSE: A coextruded polyester film for adhering metal plates is provided, which has excellent adhesibility to the metal plate and draw molding property and improves heat-proof property and shock-resistance of a metal can. And a method for preparing thereof is also provided. CONSTITUTION: The method comprises steps of: (i) surface-fractionating a copolymer polyester chip(A) containing 12-30 mol of isophthalic acid based on the total acid components and 3-10 mol of neopentyl glycol based on the total glycol components with a surface-fractionating device under a condition of the following formula (I): 1/70*PH/lr¬2 ; and (ii) after two-layer coextruding a copolymer polyester chip(B), which has an ethylene terephthalate as a main repeating unit, as a first layer and the surface-frictionated copolymer polyester chip as a second layer, biaxially orienting it. In the formula (I), P is a distance(millimeter) between screw pitches, H is a height(millimeter) of a screw peak, l is an average length(millimeter) of a chip, r is an average diameter(millimeter) of a chip and Q is a rotating speed(revolution per minute) of a surface-fractionating machine. The coextruded polyester film for adhering metal plates comprises a first layer of copolymer polyester having an ethylene terephthalate as a main repeating unit and a second layer of copolymer polyester containing 12-30 mol of isophthalic acid based on the total acid components and 3-10 mol of neopentyl glycol based on the total glycol components.
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