Basf Aktiengesellschaft

Rupert Schick

Klaus Hahn

Isidoor De Grave

Adolf Echte

Erhard Stahnecker

Paul Wittmer

Eckhard Nintz

Klaus Penzien

Manfred Walter

Heinz Weber

Heinrich Horacek

Klaus Hinselmann

Rolf Moeller

Harro Voss

Karl Seegmueller

Heinrich Wirth

Particulate polystyrene containing blowing agent and having improved expandability is based on polystyrene having a weight-average mean molecular weight of not more than from 130,000 to 180,000 and a molecular weight distribution curve in which the high molecular weight flank drops steeply. The expandable polystyrene particles are produced by polymerizing styrene in aqueous suspension in the presence of blowing agents and of chain transfer agents or styrene oligomers.

Particulate polystyrene containing blowing agent and having improved

The invention relates to pre-expanded plastic beads based on poly-para-methylstyrene with the following properties:

Pre-expanded plastic beads based on poly-para-methylstyrene

Particulate expandable styrene polymers having short minimum molding times which are coated with from 0.005 to 0.5% by weight, based on the expandable styrene polymer, of a mono- and/or poly-urethane melting below 150.degree. C. and obtained by reaction of

Particulate expandable styrene polymers having short minimum molding

Particulate expandable styrene polymers which contain from 0.0001 to 0.2% by weight, based on the styrene polymer, of an inhomogeneously distributed nucleating agent for expandable polystyrene, the nucleating agent being present only in a peripheral zone of the particles while the interior of the particles is free from nucleating agent. Nucleating agents which may be used are organic compounds having at least three bromine atoms, bonded to aliphatic or cycloaliphatic structures, in the molecule, or bromine compounds which are polymerizable, or are copolymerizable with styrene.

Particulate expandable styrene polymers for the manufacture of foams

Particulate expandable styrene polymers containing organic halogen compounds and, to improve processability, from 0.0001 to 1.0% by weight, based on the styrene polymer, of an amine which is soluble in styrene and free from hydroxyl groups.

Particulate expandable styrene polymers having good processability

Particulate, expandable styrene polymers containing a flame-proofing organic halo compound as expanding agent and also a mixture of from 2.5 to 30% by weight of a hydrocarbon of from 3 to 6 carbon atoms and from 97.5 to 70% by weight of monofluorotrichloromethane, based on the total weight of said mixture serving as expanding agent, show good processability and exhibit self-extinguishing properties even during processing.

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Limburgerhof, Germany

Rupert Schick