Abstract: Compositions, processes, and methods are provided relating to styrenic polymers, including high impact polystyrene (HIPS), also referred to as rubber-modified polystyrene. In one aspect, a process is provided for making high impact polystyrenes, comprising the steps of combining a monovinylarene component, a monovinylarene-conjugated diene block copolymer, and a conjugated diene polymer. In another aspect, the feed components form an emulsion having a continuous phase and a dispersed phase. The continuous phase comprises at least a portion of the monovinylarene component and at least a portion of the conjugated diene polymer. The dispersed phase is suspended within the continuous phase, and comprises globules having at least a portion of the monovinylarene-conjugated diene block copolymer, a remaining portion of the monovinylarene component, and a remaining portion of the conjugated diene polymer.

Abstract: In the present invention, a process is provided for producing high impact polystyrene of improved heat resistance. According to the invention, after phase inversion of the rubber-polystyrene system, a slurry of PPE in styrene is added in situ to the process. The PPE slurry in styrene contains greater than 15 wt. % of PPE and is introduced to the process at point past rubber phase inversion, preferably at point where total polymer solids is greater than 40 wt. % of the total weight of the polymerization mixture. Preferably, four continuous stirred tank reactors in series are used in the process and preferably the slurry of PPE in styrene monomer is introduced to the third CSTR.

Abstract: A continuous bulk polymerization process for making a high gloss, high impact strength polystyrene based resin having a bimodal particle size distribution containing capsule particles having an average size of 0.2 to 0.6 microns and cellular particles having an average particle size of 1.2 to 8.0 microns. The process comprises three reaction zones in series where styrene and a styrene-butadiene copolymer are fed to the first reaction zone which is maintained at pre-phase inversion conditions and no particles are allowed to form. The capsule particles form in the second reaction zone which is maintained at post-phase inversion conditions. Polybutadiene is introduced into the third reaction zone which is also maintained at post-phase inversion conditions. The cellular morphology particles form in the third reaction zone.