Abstract: An active and selective hydrocarbon partial oxidation catalyst comprises an activated partially-reduced polyoxometallate, preferably niobium polyoxomolybdate, that is prepared from a suitable polyoxoanion, which has been exchanged with a suitable cation and activated by heating to an activation effective temperature in the presence of a suitable reducing agent such as pyridinium. C3 and C4 hydrocarbons may be partially oxidized selectively to acrylic acid and maleic acid.

Abstract: A coat hanger extrusion die wherein the aperture of the die land widens along the extrusion axis of the die to the die exit opening, thereby forming an expansion zone.

Abstract: Expanded granules or a moulded article made therefrom, based on semicrystalline propylene polymer comprising, per 100 parts by weight, less than 0.035 parts by weight of volatile compounds and processes for its preparation.

Abstract: An active and selective hydrocarbon partial oxidation catalyst comprises an activated partially-reduced polyoxometallate, preferably niobium polyoxomolybdate, that is prepared from a suitable polyoxoanion, which has been exchanged with a suitable cation and activated by heating to an activation effective temperature in the presence of a suitable reducing agent such as pyridinium. C3 and C4 hydrocarbons may be partially oxidized selectively to acrylic acid and maleic acid.

Abstract: A metallocene catalyst may be temporarily and reversibly passivated by contact with an effective amount of an unsaturated hydrocarbon passivating compound.

Abstract: A catalyst system useful to polymerize and co-polymerize polar and non-polar olefin monomers is formed by in situ reduction with a reducing agent of a catalyst precursor comprising {Cp*MRR′n}+{A}− wherein Cp* is a cyclopentadienyl or substituted cyclopentadienyl moiety; M is an early transition metal; R is a C1-C20 hydrocarbyl; R′ are independently selected from hydride, C1-C20 hydrocarbyl, SiR″3, NR″2, OR″, SR″, GeR″3, SnR″3, and C═C-containing groups (R″=C1-C10 hydrocarbyl); n is an integer selected to balance the oxidation state of M; and A is a suitable non-coordinating anionic cocatalyst or precursor. This catalyst system may form stereoregular olefin polymers including syndiotactic polymers of styrene and methylmethacrylate and isotactic copolymers of polar and nonpolar olefin monomers such as methylmethacrylate and styrene.

Abstract: A catalyst system useful to polymerize and co-polymerize polar and non-polar olefin monomers is formed by in situ reduction with a reducing agent of a catalyst precursor comprising {CP* MRR′n}+{A}− wherein Cp* is a cyclopentadienyl or substituted cyclopentadienyl moiety; M is an early transition metal; R is a C1-C20 hydrocarbyl; R′ are independently selected from hydride, C1-C20 hydrocarbyl, SiR″3, NR″2, OR″, SR″, GeR″3, SnR″3, and C═C containing groups (R″═C1-C10 hydrocarbyl); n is an integer selected to balance the oxidation state of M; and A is a suitable non-coordinating anionic cocatalyst or precursor. This catalyst system may form stereoregular olefin polymers including syndiotactic polymers of styrene and methylmethacrylate and isotactic copolymers of polar and nonpolar olefin monomers such as methylmethacrylate and styrene.

Abstract: The present invention provides a composition, which includes: (a) from 10 to 55 parts by weight of a propylene polymer (A) which includes up to 2% by weight of ethylene and having a melt flow index MFI(A) of 0.1 to 30 g/10 minutes, measured according to ASTM D 1238 (1986) under a load of 2.16 kg at 230° C.; and (b) from 90 to 45 parts by weight of a polymer (B), which is a statistical copolymer of propylene which includes from 1 to 10% by weight of ethylene and having a melt flow index MFI(B) of 0.1 to 30 g/10 minutes; wherein the ethylene concentration of polymer (B) is greater than that of polymer (A). Another embodiment of the invention provides an article, which includes the above-described composition. Another embodiment of the invention provides a process for preparing the above-described composition, which includes two successive polymerization stages, wherein 10 to 55 parts by weight of polymer (A) and from 90 to 45 parts by weight of polymer (B) are respectively prepared.

Abstract: The present invention provides a composition, which includes: (a) from 55 to 74 parts by weight of a propylene polymer (A) which includes less than or equal to 1% by weight of ethylene and having a melt flow index (MFI) of 0.1 to 30 g/10 minutes, measured according to ASTM D 1238 (1986) under a load of 2.16 kg at 230° C.; and (b) from 26 to 45 parts by weight of a polymer (B), which is a statistical copolymer of propylene including from 3.5 to 15 wt % of ethylene and having an MFI of 0.1 to 35 g/10 minutes. Another embodiment of the invention provides an article, which includes the above-described composition. Another embodiment of the invention provides a process for preparing the above-described composition, which includes two successive polymerization stages, wherein 55 to 74 parts by weight of polymer (A) and from 26 to 45 parts by weight of polymer (b) are respectively prepared.

Abstract: Foamable polypropylene composition comprising a polypropylene resin having an D1238L melt flow rate of from about 0.5 to about 30 g/10 min, and a method for extruding rigid, foamed polypropylene sheet with improved surface appearance having a density in the range 0.4 to about 0.

Abstract: A catalyst system useful to polymerize and co-polymerize polar and non-polar olefin monomers is formed by in situ reduction with a reducing agent of a catalyst precursor comprising {Cp*MRR′n}+{A}− wherein Cp* is a cyclopentadienyl or substituted cyclopentadienyl moiety; M is an early transition metal; R is a C1-C20 hydrocarbyl; R′ are independently selected from hydride, C1-C20 hydrocarbyl, SiR″3, NR″2, OR″, SR″, GeR″3, and SnR″3 containing groups (R″=C1-C10 hydrocarbyl); n is an integer selected to balance the oxidation state of M; and A is a suitable non-coordinating anionic cocatalyst or precursor. This catalyst system may form stereoregular olefin polymers including syndiotactic polymers of styrene and methylmethacrylate and isotactic copolymers of polar and nonpolar olefin monomers such as methylmethacrylate and styrene.

Abstract: A catalytically active material useful to prepare vinyl acetate monomer from ethylene, acetic acid, and an oxygen-containing gas under fluid bed conditions comprises a porous microspheroidal support containing catalytically active palladium crystallites finely dispersed within the support. This catalyst material does not require incorporation of gold to maintain activity and selectivity. A process to produce a vinyl acetate fluid bed catalyst in which catalytically active small palladium crystallites are finely dispersed within the support comprises dispersing selected metal species within the support which have an affinity to palladium to form very fine crystallites of palladium. The affinity metal species may be dispersed by impregnation onto a preformed microspheroidal support or may be intimately incorporated within the support before impregnation with a soluble palladium species.

Abstract: Foamable polypropylene composition comprising a polypropylene resin having an D1238L melt flow rate of from about 0.5 to about 30 g/10 min, and a method for extruding rigid, foamed polypropylene sheet with improved surface appearance having a density in the range 0.4 to about 0.8 g/cm3.

Abstract: A method to melt process a thermoplastic, partially-crystalline, olefin polymer in a multi-temperature stage extruder wherein the polymer has a broad melting temperature range comprises setting the temperature profile of the extruder such that a portion of the polymer crystallizes in the extruder and passing the resulting partially-crystallized polymer through an extruder die.

Abstract: A ligand useful to form a metallocene olefin polymerization catalyst comprises: wherein at least R3 and R4 are substituents having at least a bulk of a t-butyl group and, optionally, wherein R1 or R2 may be a bulky substituent group.

Abstract: A process for the preparation of a fluid bed vinyl acetate (VAM) catalyst comprising impregnating a support comprising a mixture of substantially inert microspheroidal particles with a solution comprising a metal salt of Pd and M, wherein M comprises Ba, Cd, Au, La, Nb, Ce, Zn, Pb, Ca, Sr, Sb or mixtures thereof, reducing the metal salts to form a deposit of Pd and M on the support surface and impregnating the support with at least one alkali metal salt. At least 50% of the particles used for the microspheroidal support have a particle size below 105 microns.

Abstract: A process for the preparation of a fluid bed vinyl acetate (VAM) catalyst comprising impregnating a support comprising a mixture of substantially inert microspheroidal particles with a solution comprising a metal salt of Pd and M, wherein M comprises Ba, Cd, Au, La, Nb, Ce, Zn, Pb, Ca, Sr, Sb or mixtures thereof, reducing the metal salts to form a deposit of Pd and M on the support surface and impregnating the support with at least one alkali metal salt. At least 50% of the particles used for the microspheroidal support have a particle size below 105 microns.

Abstract: An improved coat hanger extrusion die wherein the aperture of the die land widens along the extrusion axis of said die to the die exit opening, thereby forming an expansion zone, and a method for extruding foamed polypropylene sheet having an improved surface appearance.

Abstract: A catalytically active material useful to prepare vinyl acetate monomer from ethylene, acetic acid, and an oxygen-containing gas under fluid bed conditions comprises a porous microspheroidal support containing catalytically active palladium crystallites finely dispersed within the support. This catalyst material does not require incorporation of gold to maintain activity and selectivity. A process to produce a vinyl acetate fluid bed catalyst in which catalytically active small palladium crystallites are finely dispersed within the support comprises dispersing selected metal species within the support which have an affinity to palladium to form very fine crystallites of palladium. The affinity metal species may be dispersed by impregnation onto a preformed microspheroidal support or may be intimately incorporated within the support before impregnation with a soluble palladium species.

Abstract: Improved apparatus for mechanically stirring a quench-cooled subfluidized particulate bed of polymerized monomer lowers lumping of polymer particles by using substantially contiguous paddle stations disposed along the drive shaft within the reactor in combination with a plurality of sub-stations in at least one paddle station class, each sub-station having a width along the shaft of no more than 50 percent of the total width of the paddle station, and sub-station paddles attached to the shaft at each sub-station so as to sweep through the particulate bed.