Abstract: The invention relates to an apparatus and a process for devolatilizing solvent-containing polycarbonate solutions. By employing the inventive apparatus, polycarbonates with low residual values of volatile constituents are produced from solvent-containing polymer melts, which improved optical properties, especially yellowness index, with the aid of an apparatus combination of a flash devolatilizer and a vented extruder.

Abstract: The invention relates to an apparatus and a process for devolatilizing solvent-containing polycarbonate solutions. By employing the inventive apparatus, polycarbonates with low residual values of volatile constituents are produced from solvent-containing polymer melts, which improved optical properties, especially yellowness index, with the aid of an apparatus combination of a flash devolatilizer and a vented extruder.

Abstract: An improvement to the phase interface process of preparing aromatic polycarbonate is disclosed. The process is characterized in that the phosgenation is carried out at 0 to 40° C., and in that the temperature of the reaction mixture at the time of addition of the catalyst at 10 to 40° C., and in that the molar ratio of aromatic dihydroxy compounds to phosgene at 1:1.05 to 1:1.20. The polycarbonate thus produced is characterized in its low content of carbamates, making it particularly suitable for the preparation of optical storage media.

Abstract: An improvement to the phase interface process of preparing aromatic polycarbonate is disclosed. The process is characterized in that the phosgenation is carried out at 0 to 40° C., and in that the temperature of the reaction mixture at the time of addition of the catalyst at 10 to 40° C., and in that the molar ratio of aromatic dihydroxy compounds to phosgene at 1:1.05 to 1:1.20. The polycarbonate thus produced is characterized in its low content of carbamates, making it particularly suitable for the preparation of optical storage media.

Abstract: A continuous process for the preparation of a thermoplastic molding composition is disclosed. Accordingly a first stream containing a molten polymer and at least one additive is introduced into a second extruded stream that contains a molten polymer to produce a combined stream. The temperature of the first stream that is below that of the second stream. The additive is in either liquid form, in solution or in dispersion.

Abstract: The invention relates to a process for drying polymeric powders and polymeric agglomerates, in particular thermoplastic aromatic polycarbonate or other thermoplastic polymers such as, for example, acrylonitrile-butadiene-styrene copolymer, in the melt, whereby thermoplastic polymeric powders or polymeric agglomerates containing water or solvent or both are freed from adhering moisture and contained solvent, accompanied by melting, in an apparatus provided with rotating baffles for cleaning the walls of the apparatus and for distribution and transport of the material being dried, by heat input through the walls or through the rotating baffles or both as well as by heat input as a result of shearing action. The process of drying and that of melting for the subsequent granulation are thereby combined.

Abstract: The present invention relates to a process for the continuous preparation of organic mono- or polyisocyanates by the reaction of the mono- or polyamines corresponding to the mono- or polyisocyanates with phosgene dissolved in an organic solvent. The phosgene solution and the amine component, optionally also in the form of a solution, are brought together inside a nozzle (1) by subjecting the stream of one component to a constriction (3) and supplying the other component into this constriction (3) from the side as partial streams through several apertures (5).

Abstract: This invention relates to a process for the continuous production of an organic monoisocyanate or polyisocyanate in a single stage reaction. A reaction mixture is formed by continuously mixing, at a temperature elevated above room temperature but not exceeding about 150.degree. C., a solution in a substantially inert organic solvent of a monoamine or polyamine corresponding to the monoisocyanate or polyisocyanate and a solution in a substantially inert organic solvent of phosgene. The reaction mixture is continuously passed upwards from below through a reaction column comprising at least 10 separate chambers separated by perforated plates, wherein each perforation of said perforated plates has a diameter of less than about 20 mm.