Abstract: A process and apparatus for passing a polymerization effluent, comprising solid polymer, unreacted monomer, diluent and minor amounts of contaminants, to a high pressure flash where most of the fluid components are flashed and wherein a slip stream comprising diluent and minor amounts of monomer is separated from the bulk of the flashed fluid components. The slip stream is subjected to olefin removal to give an essentially olefin-free stream for recycle to a catalyst mud preparation area. The bulk of the flashed fluid components are recycled directly back to the polymerization zone without expensive olefin removal, although treatment to remove other contaminants can optionally be performed. The polymer and entrained fluid is passed to a low pressure flash zone where the fluids are flashed off, compressed and joined with the flash from the high pressure flash tank.

Abstract: Catalyst systems which are suitable for the polymerization of olefinically unsaturated hydrocarbons contain, as active components, A) an amidinato metal complex of the general formula A  where M is a metal from group IIIb, IVb, Vb or VIb of the Periodic Table of Elements or a metal from the lanthanide group, X is a negative leaving atom or a negative leaving group, and the radicals X may be identical or different if (n−m)>1, R1, R2 and R3 are each a C-organic or Si-organic radical, n is the valency of M in the metal complex A and m is from 1 to 5, with the proviso that n−m≧0, and, if required, B) an acceptor compound for the substituent X of the component A as an activator.

Abstract: The present invention relates to a metallocene compound containing at least two metallocene fragments L—MX2—L which are different from one another and having the formula I where B is a bridging unit, m is an integer from 2 to 100,000, M is a metal atom of group IVb, Vb or VIb of the Periodic Table of the Elements, X are identical or different in one metallocene fragment L—MX2—L and are each, independently of one another, hydrogen, a C1-C40-hydrocarbon-containing group, an OH group, a halogen atom or a pseudohalogen, L are identical or different in one metallocene fragment and are each, independently of one another, a &pgr; ligand or another electron donor. The metallocene compound can advantageously be used as a catalyst component for olefin polymerization.

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: Disclosed are a thermoplastic elastomeric polypropylene (and other olefin homopolymerized polymers) made using a metallocene catalyst and a single olefin monomer, and a method of preparing the same to produce a chain of alternating stereo regular crystallizable segments and stereo-irregular non-crystallizable polymerized segments, the former acting as physical crosslinks between tee non-crystallizable segments to form a thermoplastic elastomeric material having good elastomeric properties.

Abstract: The invention relates to processes for producing polyolefins at pressures substantially below conventional high pressure conditions in two-phase conditions below the cloud point. The invention can involve a continuous system with optional recycle.

Abstract: A very effective catalyst system for the polymerization or copolymerization of olefins comprises a cocatalyst, preferably an aluminoxane or a supported aluminoxane, and a metallocene of the formula I in which, in the preferred form, M1 is Zr or Hf, R1 and R2 are halogen or alkyl, R3 is alkyl, R4 to R12 are alkyl or hydrogen and R13 is a (substituted) alkylene or heteroatom bridge. The metallocenes, in particular the zirconocenes, produce polymers of a very high molecular weight, in the case of prochiral monomers polymers of a very high molecular weight, very high stereoactivity and very high melting point, at high catalyst activities in the industrially particularly interesting temperature range between 50 and 80° C. In addition, reactor deposits are avoided by means of supported catalyst systems.

Abstract: An improved process of preparing a olefinic polymer of the type in which an olefinic monomer is polymerized alone or with a comonomer in a hydrocarbon solvent using a metallocene catalyst of formula (I) in the presence of a cocatalyst; wherein the improvement comprises: preparing the olefinic polymer in an aliphatic hydrocarbon solvent using a modified metallocene catalyst which is obtained by introducing at least one C5-20 alkyl substituent into the &pgr;-ligand, the alkylene bridge or silicon bridge of the metallocene catalyst of formula (I): L1L2MX2  (I) wherein, M is Ti, Zr or Hf; X is a halogen, or a C1-3 alkyl group; and L1 and L2 are each a &pgr;-ligand selected from the group consisting of cyclopentadienyl, indenyl, fluorenyl and derivatives thereof, and are optionally linked together by a C1-4 alkylene bridge optionally substituted with a C1-3 hydrocarbyl group or by a silicon bridge optionally substituted with a C1-3 hydrocarbyl group.

Abstract: A gas phase copolymerization of ethylene is disclosed. The process uses a supported single-site catalyst that contains a heteroatomic ligand and produces polyethylene that has a reduced density. Suitable heteroatomic ligands include boraaryl, azaborolinyl, pyridinyl, pyrrolyl, indolyl, carbazolyl and quinolinyl.

Abstract: A process for polymerizing ethylene feedstock to produce branched polymer of ethylene suitable for blow molding applications and having improved environmental stress crack resistance (ESCR). For example, a catalyst comprising chromium on silica is (1) calcined in air and (2) reduced in carbon monoxide and then used with hydrogen to polymerize ethylene feedstock.

Abstract: The molecular weight of polyolefins produced using iron or cobalt complexes of 2,6-pyridinecarboxaldehyde diimines or a 2,6-diacylpyridine diimines as polymerization catalysts may be lowered by carrying out the polymerization in the presence of hydrogen.

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 present invention relates to a process for the polymerization of monomers utilizing a bulky ligand hafnium transition metal metallocene-type catalyst compound, to the catalyst compound itself and to the catalyst compound in combination with an activator. The invention is also directed to an ethylene copolymer composition produced by using the bulky ligand hafnium metallocene-type catalysts of the invention, in particular a single reactor polymerization process. The hafnocene compound comprises at least one ligand substituted with at least one linear or iso alkyl substituent of at least 3 carbon atoms, and the catalyst system may comprise a mixture of two or more such hafnocenes.

Abstract: A polymerizable acrylic composition comprises: (a) at least one acrylic monomer; (b) an effective amount of an organoborane amine complex having the structure: wherein: R1 is an alkyl group having 1 to 10 carbon atoms; R2 and R3 are independently selected from phenyl-containing groups and alkyl groups having 1 to 10 carbon atoms; R4 is selected from the group consisting of CH2CH2OH and (CH2)xNH2 wherein x is an integer greater than 2; R5 is hydrogen or an alkyl group having 1 to 10 carbon atoms; and the nitrogen atom to boron atom ratio is about 1:1 to 1.5:1; and (c) an effective amount of an acid for initiating polymerization of the acrylic monomer. The polymerizable acrylic compositions are especially useful for bonding low surface energy substrates.

Abstract: A process for producing medium density polyethylene by copolymerizing ethylene and an alpha-olefinic comonomer comprising from 3 to 10 carbon atoms in the presence of a chromium-based catalyst having a support comprising silica and titania, the catalyst being fluorinated and having been chemically reduced by carbon monoxide, and in the presence of a co-catalyst selected from at least one of an aluminum alkyl and a zinc alkyl to produce a polyethylene copolymer having a density of from 0.930 to 0.945 g/cc and a dispersion index (D) of from 9 to 13.

Abstract: Provided are certain transition metal complexes which are useful as catalysts in the polymerization of olefinic monomers. In particular, the invention provides complexes of certain bidentate ligands bonded to Ni, Pd, Co, or Fe, and optionally, one or more neutral Lewis acids, and their use in the polymerization of olefins. Suitable complexes include those of the following structure: wherein M represents the transition metal, and Q, T, L, W, Z, R1,R2 and R10 represent functional groups.

Abstract: The present invention relates to a process for the polymerization of monomers utilizing a bulky ligand hafnium transition metal metallocene-type catalyst compound, to the catalyst compound itself and to the catalyst compound in combination with an activator. The hafnocene comprises at least one cyclopentadienyl ligand including at least one linear or isoalkyl substituent of at least 3 carbon atoms.

Abstract: A very effective catalyst system for the polymerization or copolymerization of olefins comprises a cocatalyst, preferably an aluminoxane or a supported aluminoxane, and a metallocene of the formula I in which, in the preferred form, M1 is Zr or Hf, R1 and R2 are halogen or alkyl, R3 is alkyl, R4 to R12 are alkyl or hydrogen and R13 is a (substituted) alkylene or heteroatom bridge. The metallocenes, in particular the zirconocenes, produce polymers of very high molecular weight, in the case of prochiral monomers polymers of very high molecular weight, very high stereotacticity and very high melting point, at high catalyst activities in the industrially interesting temperature range between 50 and 80° C.

Abstract: Composition of (a) dicyclopentadiene, by itself or in a mixture with a strained cycloolefin, and (b) a catalytic amount of at least one carbene-free, divalent-cationic ruthenium or osmium compound as a single-component catalyst, which contains at least one phosphine group and a total of 2 to 5 ligands bonded to the metal atom, and which contains acid anions for charge balancing. The compositions can be polymerized by means of heat (metathesis polymerization) and are suitable for the production of shaped articles and coatings.

Abstract: The invention addresses Group 5 metal compounds suitable as polymerization catalysts characterized by comprising one Group 15 element polyanionic ancillary ligand and three single or multidentate univalent ligands comprising Group 14-16 elements bound to the Group 5 metal, but excluding cyclopentadienyl ligands. The invention Group 5 metal compounds can be generically represented by the chemical symbols [RJ]MR′3,   (1) and [(RJ)Yn(X)]MR′2  (2) where M is a Group 5 transition metal, preferably vanadium; J is a Group 15 heteroatom ligand covalently bound to M, preferably nitrogen; R is a substituted or unsubstituted aryl, hydrocarbyl or organometalloid group covalently bound to J; each R′ is, independently, a uninegative ligand, e.g.