Method for preparing antimony-free biaxially oriented polyester film (BOPET)

Disclosed is a method for preparing an antimony-free biaxially oriented polyester film (BOPET). The method includes the steps that an antimony-free polyester chip containing silicon dioxide additives and an antimony-free super bright polyester chip are mixed, so that a raw material mixture is provided; the raw material mixture is crystallized and then dried to obtain crystallized and dried raw materials; the crystallized and dried raw materials are subjected to melt extrusion, so that a melt is obtained; and the melt is longitudinally drawn and then transversely drawn, so that the antimony-free BOPET is obtained. The antimony-free polyester chip containing the silicon dioxide additives further contains titanium catalysts, and the antimony-free super bright polyester chip contains the titanium catalysts.