Abstract: The invention relates to an improved die for the extrusion of melt strands of viscoelastic masses, and in particular to polymers and mixtures of polymers with other substances (such as solids, liquids or other polymers), where the use thereof avoids the formation of deposits in the region of the die.

Abstract: A process for treating the working surfaces of equipment used in the production and processing of polycarbonate is disclosed. The thermal treatment in an oxidative atmosphere results in resin and molded articles having improved optical quality.

Abstract: A process for treating the working surfaces of equipment used in the production and processing of polycarbonate is disclosed. The thermal treatment in an oxidative atmosphere results in resin and molded articles having improved optical quality.

Abstract: A process for purifying polycarbonate is disclosed. The process entails filtering molten polycarbonate having weight average molecular weight of 14,000 to 30,000 g/mol through at least one non-woven metal structure having a thickness of 5 to 1 mm, said structure including at least one dense layer, and at least one less dense layer wherein said dense layer is 0.05 to 0.2 mm thick and has pore size of 1 to 10 ?m to obtain pure polycarbonate.

Abstract: An improvement to the process of producing polycarbonate resin by the phase interface method is disclosed. The improvement comprising adding at least one chlorinated aromatic hydrocarbon to the organic phase.

Abstract: A device for filtering and separating a flow medium by reverse osmosis, micro filtration, ultra filtration, or nano filtration has a pressure-tight housing having an inlet for the flow medium and a first outlet for the retentate and a second outlet for the permeate. A plurality of stacked units comprised of spaced apart membrane filter elements is provided, wherein the membrane filter elements are stacked atop one another to form a stack. The stacked units are sequentially arranged in the housing. The flow medium flows in sequence through the stacked units. Each one of the membrane filter elements includes areal outer membrane elements and an areal stabilizing element positioned between the areal outer membrane elements.

Abstract: Biologically purifying sewage which is organically loaded with substances that are difficult to decompose biologically or are not decomposable biologically has the substances that are difficult to decompose biologically or are not decomposable biologically separated and concentrated to concentrate, the concentrate preferably is treated physically and/or chemically and the treated or untreated concentrate is subjected to a biological transformation or, alternatively, the concentrate is separated from the sewage to be purified.