Polyethylene terephthalate polymerisation - in solid phase by heating powdered polymer in inert gas stream in rotating inclined

摘要

Polymerisation of polyethylene terephthalate is effected in the solid phase using a polymer with an intrinsic viscosity of >=0.5, by (a) powdering the polymer, (b) feeding the powdered polymer into an inclined rotary furnace provided with elevators, (c) heating the polymer in the furnace at 220-250 degrees C., for 2-4 hrs. to effect polymsn. and increase its intrinsic viscosity, and (d) passing a hot, dry, inert gas through the polymer to eliminate volatile reaction products. Esp. useful for treating polyethylene terephthalate scrap. The high viscosity polymer can be used for prodn. of durable films, e.g. for insulating motors and for printed circuits, and for prodn. of fibres and moulding powders.