Method for preparing of weatherability thermoplastic resin

A method for preparing a weatherable thermoplastic resin comprising the steps of:

• a) preparing a seed by adding 0.05-0.2 weight parts of a water-soluble initiator to 0.5-10 weight parts of either an aromatic vinyl compound or a (meth)acrylic acid alkyl ester,
• and polymerizing;
• b) preparing an alkyl acrylate rubber polymer by adding
• i) 5-45 weight parts of an alkyl acrylate monomer,
• ii) 1-5 weight parts of an aromatic vinyl compound, a (meth)acrylic acid alkyl ester, or a vinyl cyanide compound,
• iii) 0.2-1.0 weight parts of a metal salt derivative of alkyl sulfosuccinate with C12˜C18, or a metal salt derivative of alkyl sulfuric acid ester or metal salts of sulfonate with C12˜C20, as an emulsifier, and
• iv) 0.05-2 weight parts of an oil-soluble initiator to the seed, and polymerizing;
• and
• c) preparing a thermoplastic resin by adding
• i) 10-40 weight parts of an aromatic vinyl compound,
• ii) 1-20 weight parts of a vinyl cyanide compound,
• iii) 0.5-3.0 weight parts of metal salts of rosinate or metal salts of carboxylate with C12˜C20, as an emulsifier, and
• iv) 0.05-0.2 weight parts of an oil-soluble initiator to the alkyl acrylate rubber polymer, and graft copolymerizing.