Thermoplastic resin composition, method of preparing the same, and molded article including the same

A method of preparing a thermoplastic resin composition, the method comprising:

• a step of kneading and extruding (A) 35 to 50% by weight of a polycarbonate resin having a melt flow index (300° C., load:
• 1.2 kg) of 25 to 35 g/10 min measured according to ISO 1133, (B) 25 to 40% by weight of a polyorganosiloxane-polycarbonate resin, (C) 15 to 20% by weight of a vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound copolymer, (D) 1 to 10% by weight of a polyester resin, (E) 2 to 5% by weight of an epoxy group-containing resin at 200 to 300° C., and (F) 1 to 3.3% by weight of an impact modifier, the impact modifier comprising 40 to 60% by weight of a conjugated diene rubber and 40 to 60% by weight of a (meth)acrylate-based compound, based on a total weight of the impact modifier,
• wherein the polyorganosiloxane-polycarbonate resin (B) has a melt flow index (300° C., load:
• 1.2 kg), measured according to ISO 1133, of 0.7 to 1.5 g/10 min, and a weight average molecular weight of 50,000 to 150,000 g/mol,
• wherein a weight ratio (B:C) of the resin (B) to the copolymer (C) is 2:1 to 4:1, and wherein a weight ratio (B:D) of the resin (B) to the resin (D) is 3:1 to 15:1.