Abstract: The present invention relates to a process for the preparation of polycarbonates in which an oil-in-water emulsion is maintained throughout by employing special reaction conditions.

Abstract: The invention relates to a process for the production of polycarbonates by the two-phase interfacial method in which deviations between measured and estimated variables are continuously minimized by means of a suitably selected observer or filter system on the basis of a process model with an empirical Mark-Houwink relation adapted to the process. The variables estimated by the observer/filter are converted into control variables which are used to set input streams of the production process. Product quality is kept constant, changes in load or set values are quickly intercepted and even disturbances not readily accessible to measurement are taken into account by the process control.

Abstract: The present invention relates to a process for the preparation of polycarbonates in which an oil-in-water emulsion is maintained throughout by carrying out the reaction under special conditions.

Abstract: A process for the continuous processing of vinyl polymer latices to produce thermoplastically processible vinyl polymer powder by coagulating a stream of a vinyl polymer latex by the addition of a stream of a coagulant with intensive mixing and shearing in a cascade of vessels at an average residence time per vessel of 10 to 60 minutes and at temperatures from 50 to 120.degree. C., volatile auxiliary substances and residual monomers in the polymer being optionally removed by steam distillation and part of the serum separated from the vinyl polymer being added to the stream of coagulant.

Abstract: A process for the continuous production of a thermoplastic aromatic polycarbonate is disclosed. Accordingly, in a reactor system which includes a tube reactor and a tank equipped with a stirrer, there are reacted a preheated dialkali diphenolate aqueous solution with gaseous phosgene in CH.sub.2 Cl.sub.2 and/or in chlorobenzene solution containing excess phosgene, in a mixer to form a mixed emulsion. The emulsion is then transported at least partly against the force of gravity into the tube reactor to facilitate a polycondensation reaction and in which after a residence time of at least 10 seconds and without dissipation of the heat of reaction there is added a chain terminator. The heat of reaction is dissipated in said tank and aqueous sodium hydroxide and catalyst are added to complete the reaction. The process according to the invention leads to high yields of phosgene.

Abstract: According to the invention, a special process for isolating polycarbonate from methylene chloride at temperatures of 30.degree. to 80.degree. C. in the form of a powder with residual solvent contents below 5% by weight is started up as a continuous process by starting up in a two-component nozzle, in which CO.sub.2 -containing fluid and the polymer solution are continuously combined, with a large excess of CO.sub.2 and then allowing the polycarbonate/methylene chloride/CO.sub.2 fluid system to pass through the gel-forming range of the polycarbonate/methylene chloride/CO.sub.2 phase diagram with continuous reduction of the CO.sub.2 throughput to a ratio of CO.sub.2 to organic solution of 4:1 to 2:1. The process started up in this way has a particularly long useful life.

Abstract: A continuous process for the isolation of polycarbonates from a solution of polycarbonate in methylene chloride at temperatures of 30.degree. to 80.degree. C. is disclosed. The process which yields polycarbonate in powder form having residual solvent content of less than 5% by weight, is characterized in that it entails the following steps:a) obtaining a solution of polycarbonate in methylene chloride containing 10 to 40 percent polycarbonate, said percent being relative to the total weight of the polycarbonate solution,b) mixing into said solution under pressures of 10 to 50 bar and at temperatures of 30.degree. to 50.degree. C. a fluid containing carbon dioxide resulting in a non-gelling polycarbonate/methylene/chloride/dioxide pressurized system, in which between 10 and 12% CO.sub.2 are dissolved,c) mixing said pressurized system in a two-component nozzle with additional fluid containing carbon dioxide under a pressure of 50 to 300 bar and at temperatures of 40.degree. to 150.degree. C.