Method for producing expandable polystyrene particles
AssigneeBASF Aktiengesellshaft
InventorsGuiscard Glück, Franz-Josef Dietzen, Klaus Hahn, Gerd Ehrmann
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Abstract
A process for preparing expandable particulate styrene polymers wherein from 5 to 50% by weight of expanded graphite and also, if desired, from 2 to 20% by weight of a phosphorus compound, are present as flame retardants, by suspension polymerization of styrene in the presence of the flame retardants.
Claims14
A process for preparing particulate expandable styrene polymer bead-shaped particles by polymerizing styrene, optionally together with at least one comonomer, in aqueous suspension, which comprises carrying out the polymerization in the presence of from 5 to 50% by weight, based on the monomers, of expanded graphite, and at least one aliphatic hydrocarbon blowing agent having 4 to 6 carbon atoms is added prior to, during, or after the polymerization, thereby providing expandable styrene bead-shaped particles having an average diameter of 0.2-2.0 mm.
A particulate, expandable styrene polymer bead-shaped particle which comprises a styrene polymer comprising a polymer of styrene and optionally at least one comonomer, from 5 to 50% by weight, based on the styrene polymer, of expanded graphite as uniformly distributed flame retardant, and at least one aliphatic hydrocarbon blowing agent having 4 to 6 carbon atoms, wherein the expanded graphite has an average particle size of from 20 to 100 μm, and the styrene polymer bead-shaped particles have an average diameter of 0.2-2.0 mm.
Dependencies are inferred from the claim text.