| 摘要 |
PURPOSE: A method for preparing a thermoplastic resin is provided, which has favorable yellowness, high fluidity and excellent releasability and is useful as the case for food, the case for an audio set and the interior component of a refrigerator. CONSTITUTION: The method comprises the steps of polymerizing monomers by continuous bulk polymerization under the condition of F = F1+F2, 6.2 <= F1/F2 <= 7.2 and 2.4 <= V1/V1' <= 3.0, wherein F is the total flux of a styrene monomer injected into a first and second reactors, F1 is the total flux of a styrene monomer injected into a first reactor, F2 is the total flux of a styrene monomer injected into a second reactor, V1 is the inner volume of a first reactor and V1' is the volume occupied by the reaction solution; continuously adding 2.0-2.5 wt% of a hydrocarbon compound based on the final pellet under the condition of F = F1+F2, and 2.4 <= V2/V2' <= 4.8, wherein V2 is the inner volume of a second reactor and V2' is the volume occupied by the reaction solution, and polymerizing it by continuous bulk polymerization; and separating unreacted monomers from the polymer obtained at the second reactor and cutting the polymer into a shape of pellet. Preferably the temperature of the first and second reactors is maintained to be 130-140 deg.C and 170-190 deg.C, respectively. The obtained polymer has an average molecular weight of 180,000-250,000.
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