摘要:
The present invention provides a process for the isolation of partially crystalline polycarbonate powder or oligocarbonate powder from solutions thereof, in which process the organic solvent of a polycarbonate solution is vaporized in a heat exchanger, optionally with incorporation of steam, or in a holding tube with incorporation of steam and the pasty mixture of concentrated solution, solvent vapor and optionally water is separated in a separator. In this process, the solvent vapor is condensed in a heat exchanger downstream from the separator. The solvent is vaporized in the heat exchanger by indirect input of heat through the heat exchanger walls and vaporization may be promoted by preheating the polycarbonate or oligocarbonate solution in an upstream heat exchanger or by introducing steam or both.
摘要:
This invention relates to a process for producing granulated polymer materials from polymer solutions, in which organic solvent of the polymer solution is evaporated in a heat exchanger, optionally with the admixture of steam, or in a holding tube with the admixture of steam, and the paste-like mixture of concentrated solution, solvent vapour and optionally of condensed steam is separated in a separator provided with rotating built-in components for cleaning off the walls. The pre-concentrated polymer solution is further concentrated in the separator by supplying heat by way of heating the separator walls or the rotating built-in components and by the shearing energy of the rotating built-in components.Residual degassing of the solvent is effected before granulation, e.g. in the discharge extruder of the separator which is provided with rotating built-in components, through one or more degassing zones, optionally by the additional admixture of entraining media, such as inert gas or steam, for example.
摘要:
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.
摘要:
This invention relates to a process for the production of polycarbonate agglomerate of high bulk density from polycarbonate solutions, in which the organic solvent is stripped from a solution of polycarbonate by means of steam, and which is characterised in that the resulting suspension of polycarbonate particles, condensed water and water- and solvent vapor is fed in a tube or tubular heat exchanger to a separator which is partially filled with water and which is under elevated pressure. The polycarbonate agglomerates are discharged, together with part of the water, via a pressure lock at the bottom of the separator.
摘要:
The invention relates to a two-step melt process for the production of thermoplastic, solvent-free, low-branching polycarbonates with low --OH terminal group content using a self-cleaning high-viscosity reactor.
摘要:
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.
摘要:
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.
摘要:
In a multi-shaft worm machine comprising a plurality of worm shafts rotating in the same or in opposite directions, at least one worm fitting (6) is positively connected to the associated worm shaft (3), while a countertwisting element (7) is supported in a freely rotatable manner on the opposing worm shaft portion and is driven in the opposite direction of rotation by the worm shaft (3) of the positively connected worm fitting 6.
摘要:
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.
摘要:
Evaporator apparatus (1) for the treatment of viscous media comprised of at least a feed chamber (2) having a perforated tray (3), a tube-bundle heat exchanger (4) connected thereto having perpendicularly arranged tubes (8) and a devolatilization chamber (5) connected thereto, a discharge unit (6) for the product and a vapor take-off (7) for removing volatile components, the tubes (8) of the heat exchanger (4) having a rectangular cross section over the greater part of their length.