Basf Se Corporation

Helmut Meffert

Werner Bertleff

Karl-Heinrich Schneider

Robert Bayer

Wolfgang Schrepp

Kati Schmidt

Marianna Pierobon

Valerie Andre

Michael Gotsche

Hermann Josef Feise

Ates Erk

Tobias Petsch

Julia Brodersen

Tanja Schneider

Karl Häberle

Jörg Kreβ

Ralf Mar

Ralf Lachmuth

Jörg Kress

Marcos Gomez

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

Growing community of inventors

Bobenheim am Berg, Germany

Helmut Meffert