Thermoplastic resin composition, method of preparing the same, and molded part manufactured using the same

A plated thermoplastic resin composition, the thermoplastic resin composition comprising:

• a-1) 1 to 30% by weight of a first graft polymer obtained by graft-polymerizing an aromatic vinyl compound and a vinyl cyanide compound onto a conjugated diene rubber having an average particle diameter of 0.05 μm or more and less than 0.2 μm;
• a-2) 5 to 45% by weight of a second graft polymer obtained by graft-polymerizing an aromatic vinyl compound and a vinyl cyanide compound onto a conjugated diene rubber having an average particle diameter of 0.2 to 0.5 μm;
• b) 50 to 80% by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer;
• and
• c) 1 to 10% by weight of a (meth)acrylic acid alkyl ester polymer,
• wherein the thermoplastic resin composition is a plating material, and a plating process using a chromium-free etchant is used to plate the thermoplastic resin composition.