Abstract:
A catalyst system comprising (i) a bulky ligand catalyst compound; and (ii) a novel borate activator is active for olefin polymerization. The novel borate contains at least one chelating (divalent) ligand and contains at least one fluorine atom. Preferred borate activators are provided as anilinium or carbonium salts. Highly preferred borate salts contain two perfluorinated alkoxy chelating ligands. The catalyst system may be used to produce polyethylene for “end use” applications such as polyethylene film and molded polyethylene goods.
Abstract:
The present invention provides a Ziegler-Natta catalyst useful in solution processes for the polymerization of olefins having a low amount of aluminum and magnesium. The catalysts of the present invention have a molar ratio of magnesium to the first aluminum component from 4.0:1 to 5.5:1 and molar ratio of magnesium to transition metal from 4.0:1 to 5.5:1.
Abstract:
The present invention provides a Ziegler-Natta catalyst based on titanium and vanadium useful in solution processes for the polymerization of olefins having a low amount of aluminum and magnesium. The catalysts of the present invention have a molar ratio of magnesium to the first aluminum component from 4.0:1 to 8.0:1 and molar ratio of magnesium to titanium and vanadium from 4.0:1 to 8.0:1. The invention provides a novel catalyst preparation method to substantially increase the polymer molecular weight in the high temperature ethylene polymerization process.
Abstract:
A cocatalyst system for olefin polymerization comprises an aluminoxane (especially methylaluminoxane, or “MAO”), an aluminum alkyl and a halogenated phenol. The preferred halogenated phenol is pentafluorophenol. The use of pentafluorophenol permits the substitution of a portion of the MAO cocatalyst (which is expensive) with inexpensive aluminum alkyl. The cocatalyst is most preferably employed in combination with an organometallic catalyst having at lease one pi ligand.
Abstract:
A catalyst system comprising (i) a bulky ligand catalyst compound; and (ii) a novel borate activator is active for olefin polymerization. The novel borate contains at least one chelating (divalent) ligand and contains at least one fluorine atom. Preferred borate activators are provided as anilinium or carbonium salts. Highly preferred borate salts contain two perfluorinated alkoxy chelating ligands. The catalyst system may be used to produce polyethylene for “end use” applications such as polyethylene film and molded polyethylene goods.
Abstract:
The present invention provides a Ziegler-Natta catalyst useful in solution processes for the polymerization of olefins having a low amount of aluminum and magnesium. The catalysts of the present invention contain an alkyl silanol and have a molar ratio of Si:Ti from 0.25:1 to 4:1. The catalysts are effective for the solution polymerization of olefins at high temperatures.
Abstract:
A dual reactor process for the solution and (co)polymerization of ethylene uses two different types of catalysts in the two reactors. A catalyst having a phosphinimine ligand is used in the first reactor. A Ziegler Natta catalyst is used in the second reactor. The process of this invention is comparatively easy to control and may be used to produce polyethylene products having a broad molecular weight distribution. Linear low density produced according to this invention is well suited for the manufacture of molded goods and plastic films.
Abstract:
The oligomerization of ethylene using a chromium catalyst and an aluminoxane activator is well known. The undesired formation of polyethylene as a by-product is also known to occur during prior oligomerization processes. We have discovered that the use of an aluminoxane that is prepared by non-hydrolytic means provides a highly productive activator (co-catalyst) for ethylene oligomerization and mitigates the undesired formation of by-product polyethylene.
Abstract:
The oligomerization of ethylene using a chromium catalyst having a heteroatomic ligand may be used to provide oligomerization products that are selective towards hexene and/or octene. However, such processes also typically produce some polymer as an undesirable by product. The present invention is directed towards improvements in the selective oligomerization of ethylene.
Abstract:
The oligomerization of ethylene using a chromium catalyst having a bridged diphosphine ligand can produce a selective product distribution (to predominantly hexene or predominantly octene/hexene) when activated with an aluminoxane. The oligomerization reaction also produces polymer by product—particularly when the aluminoxane is provided in a non-aromatic solvent. The present invention mitigates this problem.