Patent ID: 8916658

Claim:
Process for the transition between an ethylene co-polymerization process carried out in a polymerization reactor in the presence of a catalyst and of ethylene E and an olefin co-monomer A to produce an ethylene copolymer PEA into an ethylene co-polymerization process carried out in the same polymerization reactor in the presence of a catalyst and of ethylene E and an olefin co-monomer B to produce an ethylene copolymer PEB wherein co-monomer A and co-monomer B are different; co-monomer A and co-monomer B are both present in the reactor during at least part of the transition from PEA to PEB; and the transition is performed continuously wherein the transition is the period between the steady state production of the copolymer PEA and the steady state production of the copolymer PEB, and wherein the polymerisation production rate (“R”), defined as the amount of polymer produced by unit of time (e.g. tonnes/hour), must fulfill the following equation 0.55 ×R PEA <R T <1.45 ×R PEA wherein R PEA is the steady production rate of the copolymer PEA just before the start of the transition, and R T is the production rate of the polymer during the transition, wherein the mass of polymer present in the reactor during the transition is at least 90% of the mass of polymer just before the start of the transition.