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

A method of preparing a thermoplastic resin composition, comprising:

• kneading and extruding, at 200 to 300° C. and 100 to 500 rpm, 35 to 85% by weight of an alkyl acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A) containing alkyl acrylate rubber having an average particle diameter of 50 to 120 nm and 15 to 65% by weight of a polymethylmethacrylate resin (B),
• wherein the thermoplastic resin composition has an alkyl acrylate coverage value (X) of 70% or more as calculated by Equation 1 below:
• X={(G−Y)/Y}×100, [Equation 1]
• wherein G represents a content (wt %) of a gel based on a total weight of the thermoplastic resin composition, and Y represents a content (wt %) of the alkyl acrylate in the gel based on the total weight of the thermoplastic resin composition,
• wherein the content of the gel is measured by a method that includes:
• adding 1 g of a thermoplastic resin composition to 30 g of acetone, followed by stirring at room temperature for 12 hours, then performing centrifugation to separate insoluble matter that is not dissolved in acetone, followed by drying for 12 hours, and measuring and calculating the content of the gel from by Equation 2:
• Content of gel (%)=[Weight (g) of insoluble matter (gel)/Weight (g) of sample]×100. [Equation 2]