Abstract: A process for producing a vinyl aromatic-conjugated diene block copolymer, the process comprising solution polymerising at least one vinyl aromatic hydrocarbon and a conjugated diene in the presence of a catalyst based on an alkali metal to produce copolymer chains which end with an alkali metal and treating the copolymer chains in solution with an alkyl dicarboxylic acid having at least 2 carbon atoms and the acid being in the form of a slurry in an organic liquid with the acid being granulated and having an average granule size of less than 50 microns.

Abstract: A process for the production of ethylbenzene by the alkylation of benzene over a molecular sieve aromatic alkylation catalyst followed by transalkylation of polyalkylated aromatic components and then liquid phase alkylation. A feedstock containing benzene and ethylene is supplied to a first alkylation reaction zone containing a molecular sieve aromatic alkylation catalyst. The reaction zone is operated at temperature and pressure conditions to cause gas phase ethylation of the benzene with the production of an alkylation product comprising a mixture of ethylbenzene and polyalkylated aromatic components including diethylbenzene with xylene present in only small amounts. The output from the alkylation reaction zone is supplied to an intermediate recovery zone for the separation and recovery of ethybenzene, a polyalkylated aromatic compound component including diethylbenzene.

Abstract: Ethylbenzene is produced by alkylation over monoclinic silicalite catalysts having a weak acid site concentration of less than 50 micromoles per gram. A Feed stock containing benzene and ethylene is applied to an alkylation reaction zone having at least one catalyst bed containing a monoclinic silicalite catalyst having a weak acid site concentration of less than 50 micromoles per gram. The alkylation reaction zone is operated at temperature and pressure conditions in which the benzene is in a gaseous phase to cause gas-phase alkylation of the aromatic substrate in the presence of the silicalite catalysts to produce an alkylation product. The alkylation product is then withdrawn from the reaction zone for separation and recovery.

Abstract: A process for producing a polyethylene resin having improved mechanical properties, the process comprising polymerising ethylene in the presence of a chromium-based catalyst to make polyethylene homopolymer in a first polymerisation reactor and in a second polymerisation reactor downstream of the first polymerisation reactor copolymerising ethylene in the presence of the chromium-based catalyst and a co-catalyst from ethylene monomer and comonomer generated in-situ in the second polymerisation reactor to make polyethylene copolymer.

Abstract: A C1 symmetric metallocene compound of general formula R″(CpRb)CP′R′m) MQp for use as a catalyst component in the production of short sequence syndiotactic/isotactic block polyolefins, where Cp is a substituted cyclopentadienyl; each R is independently aryl or hydrocarbyl having 1 to 20 carbon atoms, at least position 3 of Cp is substituted with aryl, at least one other position of Cp is substituted with a non-bulky substituent, and n is an integer in the range from 2 to 4; Cp′ is substituted or unsubstituted fluorenyl; each R′ is independently hydrocarbonyl having 1 to 20 carbon atoms and m is O or an integer in the range from 1 to 8; R″ is a structural bridge to impart stereorigidity between Cp and Cp′; M is a metal from Group IIIB, IVB, VB or VIB; Q is a hydrocarbyl radical having 1 to 20 carbon atoms or a halogen; and p is the valence of M minus 2.

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: This invention is for a process for the polymerization of propylene to a minimum level of xylene solubles by use of the molar ratio of co-catalyst to external electron donor (selectivity control agent). Using a conventional supported heterogeneous Ziegler-Natta catalyst component with an trialkyl aluminum co-catalyst and an cycloalkylalkyldialkoxysilane external electron nor (selectivity control agent) in a Al/Si molar ratio of about results in the minimum amount of xylene solubles.

Abstract: A process for producing polyethylene having improved crack resistance, the process comprising copolymerizing ethylene and an alpha-olefinic comonomer comprising from 3 to 8 carbon atoms, in the presence of a chromium-based catalyst in a first reactor, feeding the polyethylene copolymer thereby produced and the chromium-based catalyst to a second reactor, and in the second reactor copolymerizing ethylene and an alpha-olefinic comonomer comprising from 3 to 8 carbon atoms, in the presence of the chromium-based catalyst thereby to produce a second polyethylene product, the first and second polyethylene products forming a combined polyethylene having a monomodal molecular weight distribution.

Abstract: A polymer blend, fibers manufactured from the blend and method of producing the fibers is disclosed. The polymer blend includes from 92 wt % to 98.5 wt % of a base polypropylene having a melt flow rate of less than 20 g/10 min, and a maximum draw ratio D, a Crimp Stability of CS, when drawn into filaments at 1000 m/sec, and from 8 wt % to 1.5 wt % of an amorphous polystyrene having a melt flow rate of less than 15 g/10 min. The polymer blend is drawable at greater than 800 m/sec to produce filaments having a maximum draw ratio of D2, the ratio of D2: D1, being greater than 1.15:1 and a Crimp Stability of CS2, the ratio of CS2: CS1 being greater than 1.45. Preferably, the base polypropylene has a melt flow rate of between 8 and 15 g/10 min. In one embodiment, the amorphous polystyrene is characterized by a melt flow between 2 and 15 g/10 min.

Abstract: Provided is polyolefin composition, the majority of which is highly isotactic polypropylene, comprising the property of heat of melting (&Dgr;Hm) greater than or equal to about 89 J/g.

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: A process for producing polyethylene in a two step polymerisation process that comprises the steps of: (a) homopolymerising ethylene in the presence of a first catalyst comprising an activated chromium catalyst in a first reactor to produce a first polyethylene fraction; (b) transferring the first polyethylene fraction produced in the first reactor and at least a portion of the first catalyst to a second reactor; (c) in the second reactor homopolymerising ethylene or copolymerising ethylene and an alpha-olefinic comonomer having from 3 to 10 carbon atoms in the presence of a second catalyst under conditions which suppress residual activity in the first catalyst to produce a second polyethylene fraction; and (d) retrieving from the second reactor polyethylene comprising a blend of the first and second polyethylene fractions.

Abstract: A process of producing polyethylene, the process comprising copolymerizing ethylene and an alpha-olefinic comonomer comprising from 3 to 8 carbon atoms in the presence of a chromium-based catalyst in a main polymerization reactor and, in a gas-phase preliminary reactor upstream of the main polymerization reactor, chemically treating the chromium-based catalyst with at least one treatment agent prior to introduction of the catalyst into the main polymerization reactor and releasing from the preliminary reactor waste gases produced during the chemical treatment.

Abstract: The invention provides a metallocene catalyst for use in preparing syndiotactic/isotactic block polyolefins. The catalyst comprises a bridged metallocene in which one of the cyclopentadienyl rings is substituted in a substantially different manner from the other ring and the cyclopentadienyl rings have lack of bilateral or pseudo-bilateral symmetry.

Abstract: A blend composition including from about 1 to about 99 weight percent syndiotactic polypropylene (sPP) and from about 99 to about 1 weight percent styrene-butadiene-styrene block copolymer (SBS) and olefin elastomer, based on the weight of the sPP, SBS and olefin elastomer. A method of making the composition includes contacting the sPP, SBS and olefin elastomer at a temperature above the melting point of the sPP and olefin elastomer, with useful articles formed therefrom.

Abstract: The present invention relates to bituminous compositions used for roofing and waterproofing membranes or material comprising asymmetrical coupled polyvinyl aromatic-polydiene block copolymers having improved physical properties over broader ranges of service temperatures than those obtained from bituminous compositions prepared with symmetrical block copolymers of similar type. The asymmetry of the copolymer which is characterised by polyvinyl aromatic endblocks of at least two different molecular weights, one high and one low, ensures improved physical performance to roofing and waterproofing membranes made from such compositions.

Abstract: The present invention relates to the production of high density polyethylene homopolymers or copolymers having a broad and monomodal molecular weight distribution wherein the polymerization process is conducted in the presence of supported metallocene-alumoxane catalysts wherein the metallocene is bridged, comprises at least a hydrogenated indenyl or fluorenyl and is isolated on its support under the form of all its conformers.

Abstract: The present invention relates to a chromium/silca-aluminophosphate catalyst, titanated under specific conditions and used for the homopolymerisation or the copolymerisation of ethylene. The polyethylene obtained with this catalyst has a high melt potential and a high shear resistance. The catalyst has a high level of activity.

Abstract: The present invention provides a lubricating oil or a lubricating oil additive, particularly suitable for a R-134a (1,1,1,2-tetrafluoroethane) or R-134 (1,1,2,2-tetrafluoroethane) refrigerant, consisting of a compound (X) that can be prepared by esterification of a polyoxyethoxylated glycerol with at least one polycarboxylic acid compound having from 2 to 20 carbon atoms, preferably from 4 to 13 carbon atoms, and at least one monocarboxylic acid compound having from 2 to 20 carbon atoms, preferably from 6 to 13 carbon atoms.

Abstract: Pigmented powder coating products based on low melting point fluorine-based terpolymers, preferably on those made from a majority of vinylidene fluoride copolymerized with tetrafluoroethylene and hexafluoropropene, are capable of providing coatings with controllable gloss properties. The process for preparing coatings from the powders is essentially characterized by the selection of the temperature at which the desired gloss can be obtained, from low to high, without degradation of the mechanical properties.