Transparent thermoplastic resin and method of preparing the same

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

• kneading and extruding an alkyl acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A), or the copolymer (A) and a matrix resin (B) comprising one or more selected from the group consisting of an aromatic vinyl compound-vinyl cyanide compound-alkyl methacrylate copolymer and an alkyl methacrylate polymer,
• wherein a transparency (haze), measured according to ASTM D-1003 under a condition of 3 mm thickness, of the thermoplastic resin is less than 5%,
• a total content of the alkyl acrylate in the thermoplastic resin is from 20 to 50% by weight,
• an alkyl acrylate coverage value (X), as calculated by Equation 1 below, of the thermoplastic resin is 65 or more:
• X={(G−Y)/Y}×100, [Equation 1]
• wherein G represents a total gel content (%) of the thermoplastic resin, and Y represents a content (% by weight) of alkyl acrylate in the gel of the thermoplastic resin, and
• wherein, based on 100% by weight in total of the copolymer (A), the copolymer (A) comprises:
• from 30 to 50% by weight of alkyl acrylate rubber (a-1) having a DLS average particle diameter of from 50 to 120 nm or a TEM average particle diameter of from 32.5 to 84 nm, and
• from 50 to 70% by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (a-2).