Patent ID: 6608150
Filing Date: 2003-08-19
Classification: C08F

Abstract:
An improved process for the polymerization of styrene monomer to produce expandable polystyrene wherein styrene is polymerized in a process comprising the following steps:A. heating an aqueous suspension comprising styrene monomer and at least two organic peroxide initiators, one of said organic peroxide initiators having a lower one hour half life decomposition temperature and at least one other of said organic peroxide initiators having a higher one hour half life decomposition temperature, for a time and at a temperature sufficient to effect at least partial decomposition of said lower half life organic peroxide and initiate polymerization of said styrene monomer, and B. subsequently raising the temperature of said aqueous suspension above the initial heating temperature to complete decomposition of the organic peroxide initiators in said suspension and provide complete polymerization of said styrene monomer, wherein the improvement comprises at least one of the organic peroxide initiators incorporated in said suspension being an â€œintermediateâ€  temperature peroxide.