Method for producing water expandable styrene polymers
AssigneeBASF SE
InventorsGuiscard Glück, Klaus Hahn, Roland Gellert
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Abstract
The invention relates to a process for preparing styrene polymers which comprise water as sole blowing agent, by polymerizing styrene in aqueous suspension in the presence of from 0.1 to 15% by weight of a solid substance insoluble in water and in styrene, for example carbon black or graphite.
Claims6
A process for preparing expandable polystyrene beads which comprises water as sole blowing agent by polymerizing styrene in aqueous suspension in the presence of magnesium pyrophosphate or tricalcium phosphate as suspension stabilizers, where the suspended styrene droplets comprise an emulsion of finely dispersed water and an emulsifying agent is present, which comprises adding, as emulsifying agent, at the start of the suspension polymerization or during its course, from 0.1 to 15% by weight, based on styrene, of carbon black or graphite having an average particle size of not more than 100 μm and a density above 1.1 g/cm3.
A process for preparing expandable polystyrene beads which comprises water as sole blowing agent by polymerizing styrene in aqueous suspension in the presence of magnesium pyrophosphate or tricalcium phosphate as suspension stabilizers, where the suspended styrene droplets comprise an emulsion of finely dispersed water and an emulsifying agent is present, which comprises adding, as emulsifying agent, at the start of the suspension polymerization or during its course, from 0.1 to 15% by weight, based on styrene, of carbon black or graphite having an average particle size of not more than 100 μm and a density above 1.1 g/cm3, the expandable polystyrene beads containing from 2 to 20% by weight water.
Dependencies are inferred from the claim text.