| 摘要 |
PURPOSE: A method for preparing the polyester film for a release carrier is provided, to improve the releasability and punchability of a film without the deterioration of physical properties, thereby to allow the leavings generated in punched to be removed easily. CONSTITUTION: The method comprises the steps of mixing 100 parts by weight of a polyester resin containing inorganic particles and 3-20 parts by weight of an elastomer; melt extruding the mixture to make a sheet; and drawing the sheet biaxially to make a film. Preferably the polyester resin contains 0.01-0.5 wt% of the inorganic particles with the size of 0.1-5 micrometers, and the mean roughness of the film is 20-60 nm. The elastomer is preferably selected from the group consisting of a grafted copolymer elastomer of normal butyl terephthalate and ethylene oxide or propylene oxide, a grafted copolymer elastomer of normal butyl terephthalate and tetramethylene ether glycol, and their mixture. Preferably at least one surface of the film is treated by corona to maintain the surface tension of a film to be over 48 dyne/cm.
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