Basf Se Corporation

Ates Erk

Robert Bayer

Marianna Pierobon

Hermann Josef Feise

Helmut Meffert

Tobias Petsch

Julia Brodersen

Jörg Kreβ

Ralf Mar

Ralf Lachmuth

Jörg Kress

A method for removing residual styrene monomers from co-extrudates comprising polystyrene and water-insoluble, crosslinked polyvinylpyrrolidone, which comprises subjecting an aqueous suspension of the particulate solid co-extrudate to a heat treatment at temperatures of 60 to 99&#xb0; C., the weight ratio of solid co-extrudate to water in the suspension being 1:1.5 to 1:20, and the concentration of the suspension being kept constant during the treatment.

Method for the production of co-extrudates composed of polystyrene and of a crosslinked polyvinylpyrrolidone with reduced residual styrene monomer content

Methods for regenerating filter aids which comprise inorganic, natural or semisynthetic filter aids. The method comprises subjecting the filter aid to a first treatment with an aqueous alkaline solution, treating the filter aid with enzymes, treating the filter aid with a surfactant, and subjecting the filter aid a second treatment with the aqueous alkaline solution. The enzyme treatment and the surfactant treatment steps may be carried out simultaneously or in any order.

Method for regenerating a filter aid

Processes comprising: (i) providing a filter aid comprising a co-extrudate of a water-insoluble polyvinylpyrrolidone and a thermoplastic polymer, (ii) treating the filter aid with aqueous alkali; (iii) subsequently treating the filter aid with an enzyme; and (iv) subsequently thereto carrying out a second treatment with aqueous alkali, to provide a regenerated filter aid, and uses therefor.

Method for regenerating an auxiliary filtering agent

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Karlsruhe, Germany

Ates Erk