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EP0770629A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

A process for preparing an in situ polyethylene blend

Assignee: Union Carbide Chemicals and Plastics Technology LLC
•
Filing: 1996-10-25
•
Granted: —
•
Expires: 2016-10-25
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Abstract

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.

Inventors

  • 👤 George Norris Foster
  • 👤 David Edward James
  • 👤 Frederick John Karol

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-30 12:08
CPC Classifications
C; C08; C08F; C08F10/00; C08F210/00; C08F210/16; C08F4/00; C08F4/42; C08F4/44; C08F4/60; C08F4/62; C08F4/64; C08F4/659; C08F4/6592; C08F4/65922; C08F2410/00; C08F2410/05; C08F4/619; C08F4/61912; C08F4/61916; C08F4/6192

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 127 words
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).

References Cited (Backward Citations)

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