Polypropylene - Vapour Phase Polymerisation (BASF)

Abstract

The basic catalyst, dry TiC 13, 1/3 A1C13 is blended and milled with triphenylphosphine oxide (10:1.67 molar ratio) to form a fixed particle size. Fresh and recycle propylene plus catalyst is fed to the first of the polymer t sat ion reactors. These contain a bed of powdered polypropylene, kept in a fluidised state by vapourised propylene feed. Conditions for the reaction are 26.5 bar and 70oC. The final step is the pellet manufacture. The crude polypropylene is separated from unreacted propylene then introduced into the extruder. Product polypropylene leaves the extruder and is pelletised and conveyed to the storage section. Unlike the liquid phase process, the solvents are not recovered or recycled.