| 摘要 |
PURPOSE: An oil resistant rubber modified polystyrene composition, its preparation method and a container for the food containing the composition are provided to improve the environmental stress cracking resistance and to reduce the content of dimmers, trimmers and remaining volatile materials. CONSTITUTION: The rubber modified polystyrene composition comprises a polybutadiene rubber particle dispersed into a polystyrene, wherein the polybutadiene rubber particle has an average volume particle diameter of 6-13 micrometers, the content of gel of the composition is 25-35 wt.%, and the composition has a swelling degree of 13-22, the remaining volatile material content of 2,000 ppm or less and a content of a dimmer and a timmer of 8,000 ppm or less. The method comprises the steps of polymerizing styrene in the presence of a polybutadiene rubber to make a polymerization solution containing the rubber modified polystyrene composition containing the rubber particle with an average volume particle diameter of 6-13 micrometers; foaming the polymerization solution; heating the foamed polymerization solution with maintaining the flow velocity distribution to be uniform; and flushing the heated one into a gas-liquid separator of a pressure of 3-40 mmHg and a temperature of 190-230 deg.C.
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