Patent attributes
The present invention relates to a process for preparing a polyethylene product having a multimodal molecular weight distribution, said process comprising the steps of: (a) feeding ethylene monomer, a diluent, at least one metallocene catalyst, optionally hydrogen, and optionally one or more olefin co-monomers into a first slurry loop reactor; and polymerizing the ethylene monomer, and the optionally one or more olefin co-monomers, in the presence of said at least one metallocene catalyst, and optionally hydrogen, in said first slurry loop reactor thereby producing a first polyethylene fraction; (b) feeding the first polyethylene fraction to a second slurry loop reactor serially connected to the first slurry loop reactor, and in the second slurry loop reactor polymerizing ethylene, and optionally one or more olefin co-monomers, in the presence of the first polyethylene fraction, and optionally hydrogen, thereby producing a second polyethylene fraction; and (c) feeding the second polyethylene fraction to a gas phase reactor serially connected to the second slurry loop reactor, and in the gas phase reactor polymerizing ethylene, and optionally one or more olefin co-monomers, in the presence of the second polyethylene fraction, and optionally hydrogen, thereby producing the polyethylene product, wherein at least 25% by weight of the polyethylene product is prepared in the first slurry loop reactor.
