Patent ID: 7511109

Claim:
A process for producing polyethylene for rotomoulding, having a density A of from 930 to 944 kg/m 3 and a melt index B of from 3 to 7.8 g/10 min, by (co-)polymerization of ethylene in a fluidised bed gas phase reactor, said process comprising determining the instantaneous density d and melt index MI of the polyethylene powder exiting a fluidized bed gas phase reactor, allowing the density and melt index to vary around their A and B values by a value of plus or minus 3 kg/m 3 for the density and plus or minus 30% for the melt index, wherein the operating temperature is controlled such that a.) an RTSE factor is first maintained in an operating envelope corresponding to the d and MI values of the polyethylene produced, and b.) then the RTSE factor is maintained between 4.2 and 4.4.