POLYESTER FILM AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A white polyester film and its preparation method are provided, to improve the concealing property, runnability and diffusion of particles and the appearance. CONSTITUTION: The polyester film comprises a polyester resin the limiting viscosity of 0.4-0.9 dl/g and comprising 60 wt% of ethylene terephthalate or more as a repeating unit; 1-25 wt% of carbon black with the mean size of 0.1-10 micrometers and the specific surface area of 100-500 m¬2/g; and 0.1-1 wt% of fine particles with the mean size of 0.01-0.1 micrometers selected from silica, alumina and CaCO3. Any one side of the polyester film is coated with a film which is made by diffusing 0.1-77 wt% of colloidal particles with the mean size of 10-50 nm selected from alumina, carbon black and silica into a mixture of a polyester resin containing a sulfonic group, a polyurethane resin containing a hydrophilic terminal group and an acryl resin. The coating density of the coated film is 0.001-0.1 g/m¬2.