Abstract: The invention relates to novel screw feed elements for multi-shaft screw feed machines having screw feed profiles rotating in the same direction in pairs and precisely abrading in pairs, to the use of the screw elements in multi-shaft screw feeding machines and to a method for extrusion of viscoelastic masses.

Abstract: The present invention relates to a reactor (10) and a process for continuous polymerization, where the reactor (10) has an essentially tubular reactor housing (16). The reactor housing (16) has a drive (38) which runs along the geometric central axis (12) in the flow direction (22) and is configured as a central shaft. A rotatably arranged scraper or wiper (36) is provided within the reactor housing (16); the scraper or wiper (36) has at least one scraper or wiper blade (42) to run along an interior side (44) of the reactor housing (16). The rotational movement of the scraper or wiper (36) results in radial mixing of a stream within the reactor housing (16) which dominates gravity effects and, by virtue of shaping of the scrapers or wipers, optionally makes plug flow or backflow within the reactor (10) possible.

Abstract: The present invention relates to a reactor (10) and a process for continuous polymerization, where the reactor (10) has an essentially tubular reactor housing (16). The reactor housing (16) has a drive (38) which runs along the geometric central axis (12) in the flow direction (22) and is configured as a central shaft. A rotatably arranged scraper or wiper (36) is provided within the reactor housing (16); the scraper or wiper (36) has at least one scraper or wiper blade (42) to run along an interior side (44) of the reactor housing (16). The rotational movement of the scraper or wiper (36) results in radial mixing of a stream within the reactor housing (16) which dominates gravity effects and, by virtue of shaping of the scrapers or wipers, optionally makes plug flow or a loop flow or backflow within the reactor (10) or else via an additional external pumped circulation system (23) possible.

Abstract: The invention is directed to an extruder (10), particularly for extruding a synthetic rubber product, which comprises a barrel (24), one or several extruder elements (12, 14), particularly one or several extruder screws and/or a kneader elements (14), arranged inside the barrel (24) for conveying the product, optionally an inlet port for feeding a stripping agent into the barrel (24) and an outlet port for removing volatile compounds from the product and, where applicable, the stripping agent. According to the invention a perforated die plate (26) is fixed to the barrel (24) in flow direction before the outlet port. Since the die plate (26) is not fixed to the extruder elements (12, 14) but to the barrel (24) a circumferential clearance between the die plate (26) and the barrel (24) is prevented so that no extruded material is passing the die plate (26) radially outside.

Abstract: The invention relates to an energy efficient, environmentally favourable process for preparing water and solvent-free rubber ionomers and/or polymer nanocomposites comprising said rubber ionomers.

Abstract: The invention relates to a device for dispersing gas into a liquid. The devise has a number n of successive zones Z1, Z2, . . . , Zn having static mixing elements, wherein each zone Zi has a length Li and an effective diameter Di. The mechanical energy input Et, which is standardised to the particular ratio Li/Di and acts on the gas/liquid mixture, increases from zone to zone in the flow direction. In this connection n is a whole number greater than or equal to 3 and i is an index which runs through the whole numbers from 1 to the number n of zones. The invention further relates to a method for dispersing gas into a liquid using the device according to the invention.

Abstract: The present invention relates to specific water and solvent-free nitrile rubbers having specific functional groups and/or end groups, a process for the production thereof and the use thereof. This process involves removing volatile compounds from a fluid (F) containing (1) at least one nitrile rubber and (2) at least one volatile compound, wherein the process comprises at least the steps of a.) treating the fluid (F) in at least one conversation unit, b.) retreating the concentrated fluid from step a.) in at least one retreating unit and c.) feeding the retreated concentrated fluid from step b.) into at least one retreating unit.

Abstract: The present invention relates to water and solvent-free polymers, in particular water and solvent-free synthetic rubber products like non-halogenated and halogenated butyl rubber products as well as a process for the production thereof. The invention further relates to a device suitable to accomplish said process.

Abstract: The present invention relates to water and solvent-free halogenated butyl rubber products as a process for the production thereof. The process comprises at least the steps of: a.) treating a fluid containing at least one halogenated butyl rubber and at least one volatile compound in at least one concentrator unit, b.) reheating the concentrated fluid and c.) feeding the reheated concentrated fluid into at least one extruder.

Abstract: The invention relates to novel screw feed elements for multi-shaft screw feed machines having screw feed profiles rotating in the same direction in pairs and precisely abrading in pairs, to the use of the screw elements in multi-shaft screw feeding machines and to a method for extrusion of viscoelastic masses.

Abstract: The present invention relates to a reactor (10) and a process for continuous polymerization, where the reactor (10) has an essentially tubular reactor housing (16). The reactor housing (16) has a drive (38) which runs along the geometric central axis (12) in the flow direction (22) and is configured as a central shaft. A rotatably arranged scraper or wiper (36) is provided within the reactor housing (16); the scraper or wiper (36) has at least one scraper or wiper blade (42) to run along an interior side (44) of the reactor housing (16). The rotational movement of the scraper or wiper (36) results in radial mixing of a stream within the reactor housing (16) which dominates gravity effects and, by virtue of shaping of the scrapers or wipers, optionally makes plug flow or backflow within the reactor (10) possible.

Abstract: The invention relates to polycarbonates with extremely low residual levels of volatile constituents and thermal degradation products, and also improved optical properties, especially Yellowness Index (YI) and good thermal stability, from solvent-containing polymer melts. The invention further relates to an apparatus and a process for preparing these polycarbonates with the aid of a devolatilizing extruder with at least three devolatilizing zones, and zones for introducing entraining agent into dispersion are present upstream of at least three devolatilizing zones.

Abstract: The present invention relates to water and solvent-free polymers, in particular water and solvent-free synthetic rubber products like non-halogenated and halogenated butyl rubber products as well as a process for the production thereof. The invention further relates to a device suitable to accomplish said process.

Abstract: An integrated process for the solution polymerization and subsequent halogenation of butyl rubber in a common medium is disclosed. The process comprises providing a solution polymerization reactor containing a C6 medium mixed with a monomer mixture comprising at least an isoolefin monomer and a multiolefin monomer in a mass ratio of monomer mixture to medium of from 61:39 to 80:20. Once polymerized, residual unreacted monomer mixture is separated from the rubber solution using a distillation process. The residual monomers may then be purified and recycled back into the reactor. The separated rubber solution is then halogenated. The process obviates the need for separating the rubber from the medium following polymerization, then re-dissolving it in another solvent for halogenation, thereby saving energy cost. The process optionally employs heat exchangers for the reactor feed streams to further reduce energy consumption.

Abstract: The present invention provides a process for preparing cyclic 1,3-keto esters in the absence of solvent, using solid-state or high viscosity reactors.

Abstract: A process for the isolation of polycarbonate produced by the interfacial polymerization process is disclosed. Accordingly, the process entails (a) evaporating the organic solvent from the solution that contains solvent and polycarbonate to obtain a material system that contains 90 to 99.95% polycarbonate, the percent being relative to the weight of the system, and (b) passing the material system through inlet openings of a separating vessel to obtain a plurality of streams of polycarbonate, on entry into the inlet openings said material system being supersaturated with volatile constituents to an extent of at least 1 bar and having a temperature of 250° to 340° C. and a flow rate of 0.1 to 20 kg/hour, and (c) degassing the streams in the separating vessel wherein the pressure is 0.1 to 20 mbar to effect degassing of the polycarbonate.

Abstract: The invention describes a process for the preparation of polycarbonate. The process includes (a) transesterifying at least one aromatic dihydroxyaryl compound and a diaryl carbonate in the melt in the presence of a catalyst, (b) mixing the melt obtained in step (a) with a foaming agent (c) passing the mixture at 250 to 340° C. through inlet openings of a separating vessel at a rate of 0.1 to 20 kg/hour, to obtain a plurality of streams of foamed polycarbonate and degassing the streams of foamed polycarbonate in the separating vessel wherein the pressure is 0.1 to 20 mbar.