A polymerization process includes contacting an ethylene feed containing ethylene monomers with a catalyst feed containing a hafnium-based or zirconium-based single-site catalyst in a solution so as to polymerize the ethylene monomers into long-chain branched high density polyethylene having on average a long-chain branch/polymer chain less than 10 and greater than 0.25. A polymerization composition includes ethylene; a hafnium-based or zirconium-based single-site catalyst; and a long-chain branched high density polyethylene polymerization product, where the long-chain branched high density polyethylene has on average a long-chain branch/polymer chain less than 10 and greater than 0.25; and where at least one of the ethylene, the catalyst, and the product is in solution.

Non-coordinating borate activators deposited upon a support material may be effective for promoting olefin polymerization in the presence of a suitable transition metal complex, particularly for gas phase and slurry polymerization reactions. The non-coordinating borate activators may be deposited upon the support material using substantially aliphatic hydrocarbon solvents, preferably in the absence of aromatic solvents, such as toluene.

Non-coordinating borate activators deposited upon a support material may be effective for promoting olefin polymerization in the presence of a suitable transition metal complex, particularly for gas phase and slurry polymerization reactions. The non-coordinating borate activators may be deposited upon the support material using substantially aliphatic hydrocarbon solvents, preferably in the absence of aromatic solvents, such as toluene.

The present invention describes a process for preparing isopropylidene bis(cyclopentadienyl)zirconium dichloride comprising the steps of: (a) reacting acetone and cyclopentadiene in the presence of sodium methoxide or sodium ethoxide so as to form 2,2-dicyclopentadienylpropane; and (b) reacting said 2,2-dicyclopentadienylpropane with zirconium(IV) chloride in the presence of n-butyl lithium so as to form isopropylidene bis(cyclopentadienyl) zirconium dichloride.

The present invention relates to melt-blown webs having no shots and improved barrier properties, whereby the melt-blown webs are made of a visbroken metallocene-catalyzed propylene homopolymer composition with specified melting temperature T.sub.m, content of 2,1 erythro regiodefects and molecular weight distribution (MWD).

The present invention relates to melt-blown webs having no shots and improved barrier properties, whereby the melt-blown webs are made of a visbroken metallocene-catalyzed propylene homopolymer composition with specified melting temperature T.sub.m, content of 2,1 erythro regiodefects and molecular weight distribution (MWD).

A polyethylene comprising of ethylene derived units and 0.5 wt % to 10 wt % C.sub.3 to C.sub.12 α-olefin derived units may be synthesized using a mixed catalyst that comprises rac-dimethylsilylbis(tetrahydroindenyl)zirconium dichloride and a zirconium co-catalyst in a mole ratio of 50:50 to 90:10, and wherein the zirconium co-catalyst is a poor comonomer incorporator as compared to the rac-dimethylsilylbis(tetrahydroindenyl)zirconium dichloride catalyst. Such a polyethylene may have a density of 0.91 g/cm.sup.3 to 0.93 g/cm.sup.3, an I.sub.2 value of 0.5 g/10 min to 2 g/10 min, an I.sub.21 value of 25 g/10 min to 75 g/10 min, an I.sub.21/I.sub.2 ratio of 25 to 75, a molar reversed-co-monomer index (RCI,m) of 30 to 180, a phase angle equal or lower than 70° at complex modulus G* of 10,000 Pa, a Θ.sub.2 of 1.5 radians to −1.5 radians, and a low density population of 50% and 70% by weight of the polyethylene.

A polyethylene comprising of ethylene derived units and 0.5 wt % to 10 wt % C.sub.3 to C.sub.12 α-olefin derived units may be synthesized using a mixed catalyst that comprises rac-dimethylsilylbis(tetrahydroindenyl)zirconium dichloride and a zirconium co-catalyst in a mole ratio of 50:50 to 90:10, and wherein the zirconium co-catalyst is a poor comonomer incorporator as compared to the rac-dimethylsilylbis(tetrahydroindenyl)zirconium dichloride catalyst. Such a polyethylene may have a density of 0.91 g/cm.sup.3 to 0.93 g/cm.sup.3, an I.sub.2 value of 0.5 g/10 min to 2 g/10 min, an I.sub.21 value of 25 g/10 min to 75 g/10 min, an I.sub.21/I.sub.2 ratio of 25 to 75, a molar reversed-co-monomer index (RCI,m) of 30 to 180, a phase angle equal or lower than 70° at complex modulus G* of 10,000 Pa, a Θ.sub.2 of 1.5 radians to −1.5 radians, and a low density population of 50% and 70% by weight of the polyethylene.

This invention relates to an oriented polyethylene film comprising polyethylene having: (A) a melt flow index of 1.0 g/10 min or more, (B) a density of 0.90 g/cm.sup.3 to less than 0.940 g/cm.sup.3, (C) a g′.sub.LCB of greater than 0.8, (D) ratio of comonomer content at Mz to comonomer content at Mw is greater than 1.0, (E) ratio of comonomer content at Mn to comonomer content at Mw is greater than 1.0, and (F) a ratio of the g′.sub.LCB to the g′.sub.Zave is greater than 1.0, where the film has a 1% secant in the transverse direction of 70,000 psi or more and Dart Drop of 350 g/mil or more.

A biaxially-oriented film comprising a polyethylene having (A) a melt flow index of 1.0 g/10 min or more, (B) a density of 0.90 g/cm3 to less than 0.940 g/cm.sup.3, (C) a g′.sub.LCB of greater than 0.8, (D) ratio of comonomer content at Mz to comonomer content at Mw is greater than 1.0, (E) ratio of comonomer content at Mn to comonomer content at Mw is greater than 1.0, and (F) a ratio of the g′.sub.LCB to the g′.sub.zave is greater than 1.0, and where the film has a 1% secant in the transverse direction of 70,000 psi or more and Dart Drop of 350 g/mil or more.