THERMOPLASTIC RESIN COMPOSITION HAVING EXCELLENT IMPACT RESISTANCE, TRANSPARENCY AND MOISTURE RESISTANCE AND PREPARATION METHOD THEREOF

摘要

PURPOSE: A thermoplastic resin composition and its preparation method are provided, to improve the impact resistance, the transparency and the moisture resistance. CONSTITUTION: The method comprises the steps of inputting 40-60 parts by weight of a monomer mixture comprising an acrylonitrile monomer, a styrene-based monomer and an alkyl methacrylate and 0.1-0.5 parts by weight of a hydroperoxide-based oil-soluble initiator to a reactor in the presence of 40-60 parts by weight of a rubbery polymer latex with an average particle diameter of 0.2-0.5 micrometers, adding an emulsifier and an auxiliary initiator and graft polymerizing the monomers; inputting 0.3-0.8 parts by weight of a water-soluble initiator to the reactor when the polymerization conversion rate reaches 90 %, inputting the monomer mixture continuously or several times for 1-3 hours and graft polymerizing the monomers; and coagulating the graft polymerized latex at a coagulation bath containing a metal-based electrolyte coagulant and a strong acid coagulant. The monomer mixture comprises 30-80 wt% of an alkyl methacrylate, 10-40 wt% of an aromatic vinyl compound and 1-20 wt% of an unsaturated nitrile compound, and 10-30 wt% of the monomer mixture is inputted at the first step and the rest (70-90 wt%) is at the second step.