Abstract: The present invention provides a method for varying the melting points and molecular weights of polyolefins by changing the structure of the catalyst used in the polymerization. The catalysts that are useful in the present invention are chiral, stereorigid metallocene catalyst of the formula R″(C5R′m)2MeQ. The catalysts include a bridge structure between the (C5R′m) groups and may contain substituents on the groups. It has been discovered that the melting points and molecular weights of the polymers produced by such catalysts are influenced by the bridge and substituents added to the (C5R′m) groups. Thus, the present invention provides a method for varying the melting points of the polymer product and a method of varying the molecular weights of the product by changing the components and structure of the metallocene catalysts. The present invention also provides a process for polymerizing olefins in which the melting points and/or molecular weights of the product may be controlled.

Abstract: New metallocene compounds are described where the ligand contains at least one open-pentadienyl containing radical characterized by a cyclic or acyclic, six &pgr; electron, delocalized, five atomic center structure. These metallocenes can advantageously be used in catalyst systems for the polymerization of olefins to generate a wide variety of different polymers including HDPE, LLDPE, ethylenelpropylene/(diene) elastomers, tactiospecific C3+&agr;-olefin polymers, intimate mixture thereof and the like.

Abstract: A radar detector for exploration of subsurface embedded objects comprising an antenna array (1) for high-frequency electromagnetic waves, which is connected and individually switchable with at least one transmit/receive unit, a time-controlled signal processor, an evaluation device for SAR and a display device. The antenna array (1) exhibiting at least three antennas (sx, rx, sy, ry) scamiing an area by their positioning.

Abstract: This invention is for a metallocene compound which can be used in a catalyst system to produce hemiisotactic polymer. The compound is a bridged metallocene compound having dissimilar cyclopentadienyl groups and no bi-lateral symmetry. One example of the compound is isopropylidene(3-methylcyclopentadienyl-1-fluorenyl) zirconium dichloride. The catalyst of this invention can be converted to an ionic metallocene catalyst by an ionizing agent, such as methylaluminoxane. The polymer produced with this catalyst is characterized by having an isotactic structure effecting only every other asymmetric carbon atom. In the case of polypropylene, every other methyl group is on the same side of the principal polymer chain as represented by a Fisher projection. The remaining methyl groups can be either on the same side or on the opposite side of the principal polymer chain. The polymer produced with the catalyst of this invention can be used as a plasticizer.

Abstract: The present invention provides a method for varying the melting points and molecular weights of polyolefins by changing the structure of the catalyst used in the polymerization. The catalysts that are useful in the present invention are chiral, stereorigid metallocene catalyst of the formula R″(C5R′m)MeQ. The catalysts include a bridge structure between the ((C5R′m) groups and may contain substituents on the groups. It has been discovered that the melting points and molecular weights of the polymers produced by such catalysts are influenced by the bridge and substituents added to the (C5R′m) groups. Thus, the present invention provides a method for varying the melting points of the polymer product and a method of varying the molecular weights of the product by changing the components and structure of the metallocene catalysts. The present invention also provides a process for polymerizing olefins in which the melting points and/or molecular weights of the product may be controlled.

Abstract: This invention is for a metallocene catalyst component comprising a bridged metallocene in which the two substituted indenyl rings are complexed to a metal hydrocarbyl or metal halide. This metallocene catalyst component is useful for polymerizing olefins having three or more carbon atoms to produce a polymer with a isotactic stereochemical configuration. The catalyst component is a stereorigid metallocene described by the formula: R″(CpR2C4R4)(CpR′2C4R′4)MeQk wherein (CpR2C4R4) and (CpR2C4R4) are substituted indenyl rings; each R and R′ is a hydrogen or a hydrocarbyl radical having 1-20 carbon atoms; R″ is a structural bridge between the two indenyl rings imparting stereorigidity to the indenyl rings; Me is a transition metal; and each is a hydrocarbyl radical or is a halogen. Further, one R and R′ is a hydrocarbyl radical having 1-20 carbon atoms in a proximal position adjacent to the bridgehead carbon of the indenyl rings.

Abstract: A process for polymerizing addition polymerizable monomers using hafnocenes catalysts/catalyst precursors having a selected symmetry condition under condensed polymerization conditions where the symmetry condition is such that the resulting polymer has varying degrees of tactioselectivity or copolymers having regions of varying degrees of tactioselectivity. Preferred classes of the haflocenes are capable of generating near pure isospecific and syndiospecific polymers in solution or in bulk polymerization conditions.

Abstract: The invention provides for highly crystalline syndiotactic polypropylene comprising a high percentage of racemic (r) dyads. The high crystallinity may be due to the polymerization mechanism of metallocene catalysts of a particular structure which appear to produce syndiotactic polypropylene of a new microstructure.

Abstract: Isospecific and/or syndiospecific catalysts and processes for the propagation of an isotactic and/or syndiotactic polymer chain derived from an ethylenically unsaturated monomer which contains 3 or more carbon atoms or is a substituted vinyl compound. The catalysts comprise a stereorigid, stereodirected and stereolocked metallocene and/or metallocene cation catalysts, characterized by having &bgr; stereodirecting substituents and &agr; stereolocking substituents such that the catalysts have overall either Cs or C2 (or pseudo-Cs or C2) symmetry and such that the substituents define the orientation of the growing polymer chain end and resulting in tactioselectivity of successive monomer additions. Methods are also described for the preparation and use of these unique catalysts.

Abstract: A process for polymerizing addition polymerizable monomers using titanocenes catalysts/catalyst precursors having a selected symmetry condition under condensed polymerization conditions where the symmetry condition is such that the resulting polymer has varying degrees of tactioselectivity or copolymers having regions of varying degrees of tactioselectivity. Preferred classes of the titanocenes are capable of generating near pure isospecific and syndiospecific polymers in solution or in bulk polymerization conditions.

Abstract: A process for polymerization of olefins having increased molecular weight and melting point uses a catalyst formed by combining a chiral, stereorigid metallocene compound with an organoaluminum compound. The metallocene compound has a silicon hydrocarbyl radical as an interannular bridge between two cyclopentadienyl or substituted cyclopentadienyl rings which are coordinated with a metal which is bonded to a hydrocarbon radical or a halogen. The cyclopentadienyl rings are described by the formula (C.sub.5 R'.sub.m) wherein R' is hydrogen or hydrocarbyl radical having from 1-20 carbon atoms, each R' being the same or different. The metal is a group 4b, 5b or 6b metal as designated in the Periodic Table of Elements.

Abstract: New metallocene ligand systems and catalysts/catalyst precursors are described where the ligand system contains at least one open-pentadienyl ligand characterized by an acyclic six .pi. electron delocalized, five atomic center structure. The open pentadienyl ligand is bonded to either another pentadienyl ligand or a Cp ligand by a bridging group. The metal is from group 3-5 or the Lanthanides. These metallocene catalysts/catalyst precursors optionally in combination with co-catalysts can be used to generate a wide variety of different polymer types including HDPE, LLDPE, LHDPE, ethylene/propylene elastomers, tactiospecific C3+ .alpha.-olefins, intimate mixture thereof and the like.

Abstract: The invention is a process for using a metallocene catalyst system in polymerization of olefins. The metallocene is contacted with the Lewis acid. The aluminum alkyl is contacted with the olefin. The two mixtures are contacted with each other under polymerization conditions.

Abstract: A catalyst system for polymerization of olefins having increased molecular weight and melting point is disclosed. A chiral, stereorigid metallocene compound having a silicon hydrocarbyl compound as an interannular bridge between two cyclopentadienyl or substituted cyclopentadienyl rings described by the formula (C.sub.5 R'.sub.m) wherein R' is hydrogen or hydrocarbyl radical having from 1-20 carbon atoms, each R' being the same or different, is combined with an organoaluminum compound. The cyclopentadienyl ligands are coordinated with a metal of a group 4b, 5b, or 6b metal as designated in the Periodic Table of Elements. The metal is also bonded to a hydrocarbon radical or a halogen.

Abstract: Metallocene catalysts and their preparation and use in the polymerization of olefins. Specifically, the catalysts and processes relate to polymerization of olefins in which an aluminum ionizing agent containing a triphenylcarbenium ion is utilized in preparing the catalyst. The preparation of an olefin polymerization catalyst comprising a metallocene-type catalyst and triphenylcarbenium tetrakis(pentafluorophenyl)aluminate is disclosed.

Abstract: Metallocene catalysts and their preparation and use in the polymerization of olefins. Specifically, the catalysts and processes relate to polymerization of olefins in which an aluminum ionizing agent containing a triphenylcarbenium ion is utilized in preparing the catalyst. The preparation of an olefin polymerization catalyst comprising a metallocene-type catalyst and triphenylcarbenium tetrakis(pentafluorophenyl)aluminate is disclosed.

Abstract: This invention is for a method for varying the melting points and molecular weights of syndiotactic polyolefins by using metallocene catalysts with substituents on the aryl rings of a fluorene ligand in certain positions. Electron donating substituents, for example, dialkylamino, halogen, and alkoxy groups, when present on fluorene at C1, C2, C3 or C2 and C7 render the catalyst less active and decrease the polymer molecular weight. Electron donating substituents, such as alkyl, dialkylamino, halogen or alkoxy, at C4 not only increased the catalyst efficiency but also dramatically increased the polymer molecular weight. Bulky hydrocarbyl substituents, such as alkyl, cyaloalkyl and aryl groups, at C2 and C7 increase the melting point. Bulky substituents such as hydrocarbyl groups like alkyl, cycloalkyl, aryl, alkoxy and dialkylamino groups etc., at C4/C5 decrease the melting point. When multiple substituents are present on fluorene, their effects are additive.

Abstract: This invention is for a method for varying the melting points and molecular weights of syndiotactic polyolefins by using metallocene catalysts with substituents on the aryl rings of a fluorene ligand in certain positions. Electron donating substituents, for example, dialkylamino, halogen, and alkoxy groups, when present on fluorene at C1, C2, C3 or C2 and C7 render the catalyst less active and decrease the polymer molecular weight. Electron donating substituents, such as alkyl, dialkylamino, halogen or alkoxy, at C4 not only increased the catalyst efficiency but also dramatically increased the polymer molecular weight. Bulky hydrocarbyl substituents, such as alkyl, cycloalkyl and aryl groups, at C2 and C7 increase the melting point. Bulky substituents such as hydrocarbyl groups like alkyl, cycloalkyl, aryl, alkoxy and dialkylamino groups etc., at C4/C5 decrease the melting point. When multiple substituents are present on fluorene, their effects are additive.

Abstract: This invention uses a new method of producing ionic metallocene compounds. These compounds are useful as catalysts for polymerization of olefins, primarily propylene. This method uses an ionizing agent which ionizes the neutral metallocene compound. The ionizing ionic compound does not contain an active proton and contains a carbonium, oxonium or sulfonium cation. The anion of the ionizing ionic compound is not coordinated or is only loosely coordinated to the metallocene cation and is chemically unreactive with the metallocene cation. Examples of such compounds are triphenylcarbenium tetrakis(pentafluorophenyl)boronate, triphenylcarbenium tris(pentafluorophenyl)phenyl boronate and triphenylcarbenium tris(pentafluorophenyl)4-trimethylsilyl-2,3,5,6-tetrafluorophenylboronate.The process of making catalysts with this invention produces catalysts having high activity and does not produce by-products which can inhibit catalyst activity. This new synthesis is a clean reaction which does not produce a Lewis base.

Abstract: Compounds useful as catalyst components for olefin polymerization. The compounds comprise derivatives of cyclopentadienyl complexes of the ZR or HF.