BIAXIALLY ORIENTED POLYESTER FILM FOR DIRECT EXTRUSION COATING AND PREPARATION THEREOF

摘要

PURPOSE: A biaxially oriented polyester film for direct extrusion coating is provided, which has good moisture-proof property and good adhesion, which maintains good adhesion even under high humidity, and which can be directly extruded without a separate post-treatment. CONSTITUTION: A biaxially oriented polyester film comprises polyester film and a primer layer formed on at least one side of the film wherein the primer layer comprises a modified polybutadiene resin. The polyester film is prepared by the process comprising a) melt extruding polyester resin and cooling the resin to produce non-oriented sheet; b) orienting the sheet in machine direction; c) orienting the sheet in cross-machine direction; and d) heat setting the biaxially oriented sheet wherein the process is characterized in that the process further comprises the step of forming a primer layer after the steps a), b) or c) and the primer layer forming step comprises applying water dispersible composition containing 1 to 10 wt% of modified polybutadiene resin, 0.01 to 0.5 wt% of surfactant and 0.01 to 2.0 wt% of aminofunctional silane to at least one face of the non-oriented or oriented sheet.