Disclosed herein are ethylene-based polymers produced using dual metallocene catalyst systems. These polymers have low densities, high molecular weights, and broad molecular weight distributions, as well as having the majority of the long chain branches in the lower molecular weight component of the polymer, and the majority of the short chain branches in the higher molecular weight component of the polymer. Films produced from these polymers have improved impact and puncture resistance.

A process for the preparation of polyolefins by polymerizing olefins at temperatures of from 20 to 200 C. and pressures of from 0.1 to 20 MPa in the presence of a polymerization catalyst and an antistatically acting composition in a polymerization reactor, wherein the antistatically acting composition is a mixture comprising an oil-soluble surfactant and water and the use of an antistatically acting composition comprising an oil-soluble surfactant and water as antistatic agent for the polymerization of olefins at temperatures of from 20 to 200 C. and pressures of from 0.1 to 20 MPa in the presence of a polymerization catalyst.

Catalyst systems and methods for making and using the same. A method of polymerizing olefins to produce a polyolefin polymer with a multimodal composition distribution, includes contacting ethylene and a comonomer with a catalyst system. The catalyst system includes a first catalyst compound and a second catalyst compound that are co-supported to form a commonly supported catalyst system. The first catalyst compound includes a compound with the general formula (C.sub.5H.sub.aR.sup.1.sub.b)(C.sub.5H.sub.cR.sup.2.sub.d)HfX.sub.2. The second catalyst compound includes at least one of the following general formulas: ##STR00001##
In both catalyst systems, the R groups can be independently selected from any number of substituents, including, for example, H, a hydrocarbyl group, a substituted hydrocarbyl group, or a heteroatom group, among others.

A method for altering the melt flow ratio (MFR) of ethylene copolymers made in a gas phase reactor using a supported Ziegler-Natta catalyst treated with a catalyst modifier. The method involves changing the amount of the catalyst modifier added to the supported Ziegler-Natta polymerization catalyst to effect changes in the MFR of the resulting polymer.

An ethylene-?-olefin copolymer includes moieties derived from ethylene and moieties derived from an ?-olefin comprising 3 to 10 carbon atoms, wherein the copolymer has: a short chain branching ratio (SCBR) of >1.40; a short chain branching content of ?15.0/1000 C; a molecular weight distribution M.sub.w/M.sub.n of ?10.0; and a quantity of polymer moieties derived from an ?-olefin comprising 3 to 10 carbon atoms of ?1.0 and ?20.0 wt %, with regard to the total weight of the copolymer. Such copolymer demonstrates improved melt processability, as well as allows for manufacturing of films having desirable mechanical properties, in particular in production of films such as by blown film production or by cast film production.

The present technology relates to a method of introducing a supported antistatic compound that does not comprise a transition-metal-based catalyst component for use in an olefin polymerization reactor. In some embodiments, the methods disclosed herein avoid the formation of polymer agglomerates in the reactor and minimize potentially negative effects on catalyst yield.

Modified chromium-based catalyst compositions for olefin polymerization are disclosed. The modifiers prevent or reduce catalyst particle aggregation providing improved catalyst particle dispersion and consistent flow index response of the compositions in olefin polymerization.

Disclosed herein are ethylene-based polymers produced using dual metallocene catalyst systems. These polymers have low densities, high molecular weights, and broad molecular weight distributions, as well as having the majority of the long chain branches in the lower molecular weight component of the polymer, and the majority of the short chain branches in the higher molecular weight component of the polymer. Films produced from these polymers have improved impact and puncture resistance.

A polymerization catalyst system, a method of using the polymerization catalyst system, and a polymer produced with the catalyst system. The polymerization catalyst system has a non-metallocene catalyst and a metallocene catalyst. The metallocene catalyst has the formula: wherein R.sup.1 and R.sup.2 are each independently, phenyl, methyl, chloro, fluoro, or a hydrocarbyl group.

A method for altering the melt flow ratio (MFR) of ethylene copolymers made in a gas phase reactor using a supported Ziegler-Natta catalyst treated with a catalyst modifier. The method involves changing the amount of the catalyst modifier added to the supported Ziegler-Natta polymerization catalyst to effect changes in the MFR of the resulting polymer.