Abstract:
Continuous production of styrene polymers which contain an expanding agent and which are in the form of granules by extrusion of a mixture of a melt of the polymer with the expanding agent and rapid cooling of the extruded mixture, wherein excess expanding agent is first mixed with the melt and then the excess of expanding agent is evaporated. In this way both the production of a homogeneous mixture and the cooling of the mixture prior to extrusion to temperatures just above the softening point of the mixture are facilitated.
Abstract:
Copolymers of ethylene with 10 to 98 percent by weight of conventional comonomers are made by copolymerization in aqueous dispersion, at least a part of the heat of polymerization being removed by evaporation of the ethylene. The vapors are cooled by a cooling medium by heat exchange, in a cooling zone situated above the polymerization vessel and communicating with the latter, the hot vapors being fed to the upper end of the cooling zone, the cooled vapors returning to the polymerization vessel, so that the vapors are cooled by the cooling medium while they are flowing downward.
Abstract:
A CONTINOUS PROCESS FOR THE REMOVAL OF RESIDUAL MONOMERS FROM SOLUTION OF ACRYLONITRILE POLYMERS IN DIMETHYLFORMAMIDE AND FOR CONCENTRATING THE SOLUTIONS IN A SEQUENCE OF SEPARATING ZONES PRESSURE RELEASE ZONES, HEATING ZONES AND PRESSURE RELEASE ZONES. THE PROCESS IS DISTINGUISHED BY SHORT RESIDENCE TIMES AND ONLY SLIGHT DAMAGE TO THE POLYMER SOLUTIONS. THE SOLUTIONS OBTAINED MAY SERVE FOR THE PRODUCTION OF FILAMENTS, THREADS OR FIBERS.