A spray-dried zirconocene catalyst system comprising a zirconocene catalyst and a hydrophobic fumed silica, which supports the zirconocene catalyst. A spray-drying method of making same. Polyolefins; methods of making and using same; and articles containing same.

The invention relates to particles with an average particle size of 300 to 1000 μm, comprising a modified polyvinyl alcohol having vinyl alcohol units and structural units represented by formula (1), wherein a content of the vinyl alcohol units is 60 to 90 mol % based on the total structural units: ##STR00001## wherein R.sup.1 represents a hydrogen atom or a methyl group. Thus, the present invention provides particles containing a modified polyvinyl alcohol having high water solubility and high affinity for a photosensitive monomer, which are highly photosensitive.

The present invention relates to an ultra-high molecular weight polyethylene (UHMWPE) powder having a BET specific surface area of ≥0.50 m.sup.2/g as determined in accordance with ISO 9277 (2010). Such UHMWPE powder allows for preparation of a gel solution comprising the powder to a desired swelling ratio at moderate temperatures within a reduced swelling period.

The present invention relates to an ultra-high molecular weight polyethylene (UHMWPE) powder having a BET specific surface area of ≥0.50 m.sup.2/g as determined in accordance with ISO 9277 (2010). Such UHMWPE powder allows for preparation of a gel solution comprising the powder to a desired swelling ratio at moderate temperatures within a reduced swelling period.

Particles of an acrylic polymer comprising a constituent unit (A) derived from methyl methacrylate and a constituent unit (B) derived from a (meth)acrylic acid alkyl ester in which the alkyl group has 2 to 8 carbon atoms, wherein the particles having electrostatic buildup inhibition rate of 90 to 99.9° as obtained by a specific method.

A process of preparing a solid catalyst component for the production of polypropylene includes a) dissolving a halide-containing magnesium compound in a mixture, the mixture including an epoxy compound, an organic phosphorus compound, and a hydrocarbon solvent to form a homogenous solution; b) treating the homogenous solution with an organosilicon compound during or after the dissolving step; c) treating the homogenous solution with a first titanium compound in the presence of a first non-phthalate electron donor, and an organosilicon compound, to form a solid precipitate; and d) treating the solid precipitate with a second titanium compound in the presence of a second non-phthalate electron donor to form the solid catalyst component, where the process is free of carboxylic acids and anhydrides.

A process of preparing a solid catalyst component for the production of polypropylene includes a) dissolving a halide-containing magnesium compound in a mixture, the mixture including an epoxy compound, an organic phosphorus compound, and a hydrocarbon solvent to form a homogenous solution; b) treating the homogenous solution with an organosilicon compound during or after the dissolving step; c) treating the homogenous solution with a first titanium compound in the presence of a first non-phthalate electron donor, and an organosilicon compound, to form a solid precipitate; and d) treating the solid precipitate with a second titanium compound in the presence of a second non-phthalate electron donor to form the solid catalyst component, where the process is free of carboxylic acids and anhydrides.

Catalyst compositions containing a metallocene compound, a solid activator, and a co-catalyst, in which the solid activator or the supported metallocene catalyst has a d50 average particle size of 15 to 50 μm and a particle size distribution of 0.5 to 1.5, can be contacted with an olefin in a loop slurry reactor to produce an olefin polymer. A representative ethylene-based polymer produced using the catalyst composition has excellent dart impact strength and low gels, and can be characterized by a HLMI from 4 to 10 g/10 min, a density from 0.944 to 0.955 g/cm.sup.3, a higher molecular weight component with a Mn from 280,000 to 440,000 g/mol, and a lower molecular weight component with a Mw from 30,000 to 45,000 g/mol and a ratio of Mz/Mw ranging from 2.3 to 3.4.

Catalyst compositions containing a metallocene compound, a solid activator, and a co-catalyst, in which the solid activator or the supported metallocene catalyst has a d50 average particle size of 15 to 50 μm and a particle size distribution of 0.5 to 1.5, can be contacted with an olefin in a loop slurry reactor to produce an olefin polymer. A representative ethylene-based polymer produced using the catalyst composition has excellent dart impact strength and low gels, and can be characterized by a HLMI from 4 to 10 g/10 min, a density from 0.944 to 0.955 g/cm.sup.3, a higher molecular weight component with a Mn from 280,000 to 440,000 g/mol, and a lower molecular weight component with a Mw from 30,000 to 45,000 g/mol and a ratio of Mz/Mw ranging from 2.3 to 3.4.

The present application relates to a process for producing ethylene polymer in a polymerization process comprising polymerisation of ethylene, optionally with comonomers selected from C.sub.3-C.sub.20-alpha-olefins, preferably selected from C.sub.4-C.sub.10-alpha-olefins, in the presence of a Ziegler-Natta catalyst under polymerisation conditions in at least one polymerisation stage carried out in a solution, slurry or gas-phase reactor or in combinations thereof, wherein the Ziegler-Natta catalyst comprises (A) a solid Ziegler-Natta catalyst component and (B) a cocatalyst, wherein the solid Ziegler-Natta catalyst component (A) comprises a solid support of a Mg compound, a transition metal of Group 4 to 6 and an internal electron donor.