Abstract A process for the production of an in situ polyethylene blend comprising contacting at least one metallocene based catalyst system with one or more alpha-olefins in each of two or more reactors connected in series, in the gas phase, under polymerization conditions, with the provisos that: (a) ethylene is introduced into each reactor; (b) optionally, an alpha-olefin having at least 3 carbon atoms or a diene is introduced into at least one reactor; (c) the mixture of ethylene polymer matrix and catalyst formed in the first reactor in the series is transferred to the subsequent reactors in the series; and (d) the polymerization conditions in each reactor are such that a high molecular weight polymer is formed in at least one reactor and a low molecular weight polymer is formed in at least one other reactor.
A process for the production of an in situ polyethylene blend comprising contacting at least one metallocene based catalyst system with one or more alpha-olefins in each of two or more reactors connected in series in the gas phase under polymerization conditions, with the provisos that: (a) ethylene is introduced into each reactor; (b) optionally, one or more alpha-olefin having at least 3 carbon atoms or diene comonomer is introduced into at least one reactor; (c) the mixture of ethylene polymer matrix and catalyst formed in the first reactor in the series is transferred to the subsequent reactors in the series; and (d) the polymerization conditions in each reactor are such that the resultant polymer is multimodal in molecular weight distribution or comonomer composition distribution or both.
Claim 2
Dependent Claim
20 words
A process as claimed in claim 1 wherein the metallocene based catalyst system is added only to the first reactor.
Claim 3
Dependent Claim
18 words
A process as claimed in claim 1 wherein the metallocene based catalyst system is added to each reactor.
Claim 4
Dependent Claim
42 words
A process as claimed in claim 1 wherein the metallocene based catalyst system is added to the reactor making the polyethylene with lower molecular weight and a Ziegler/Natta catalyst system is added to the reactor making the polyethylene with higher molecular weight.
Claim 5
Dependent Claim
24 words
A process as claimed in any one of the preceding claims wherein the metallocene is a carbamate or carboxylate of Formula I or II.
Claim 6
Dependent Claim
21 words
A process as claimed in any one of the preceding claims wherein the metallocene based catalyst system is an unsupported system.
Claim 7
Dependent Claim
15 words
A process as claimed in claim 6 wherein the metallocene is indenyl zirconium tris(diethyl carbamate).