Manufacture of butyl rubber.

摘要

The invention relates to a continuous process for the manufacture of butyl rubber in which the monomers are polymerised using a halogenated polymerisation medium in a self-cleaning screw extruder at a constant pressure under boil- ing plug-flow conditions by means of a modified aluminium halide catalyst which operates at high temperature (relative to prior art very low temperatures of e.g. -100°C). In contrast to prior art slurry processes, the polymerisation mixture forms a sticky, highly viscous mass which is conveyed by screw action to the extruder outlet as polymerisation proceeds. The butyl rubber product is separated at a high concentration from vapours of unreacted monomers and polymerisation medium which are recycled. Cooling is effected by vapourisation of a portion of the mixture of monomers and polymerisation medium in a flash tank before supply to the extruder and returning the vapourised fraction and recycle vapours to the flash tank through, in succession, a compressor, heat exchanger and throttle valve.

By using the process of the invention, the total energy consumption in butyl rubber manufacture can be cut to about 20% of that of prior art processes.