A mixed metallocene catalyst system can comprise at least one metallocene catalyst compound comprising a structure represented by formula (A) below and optionally at least one other metallocene catalyst compound having a structure represented by formula (B) below:

##STR00001##

A mixed metallocene catalyst system can additionally include a non-coordinating anion type activator comprising a supported alumoxane or aluminum alkyl, and optionally a scavenger. A process for making a polymeric product can comprise: contacting a C.sub.2-C.sub.22 alpha-olefin feed with the catalyst system to obtain a polymerization reaction mixture; and obtaining a polymer product from the polymerization reaction mixture. A polymer product can be made by the process.

This invention relates to a supported catalyst system comprising a first iron based catalyst, a second group 4 metal catalyst, a support material, and an activator; wherein the first catalyst is represented by Formula (I) and the second catalyst is represented by Formula (II):

##STR00001##

Provided are an ethylene-based polymer having excellent long-term pressure resistance characteristics and a pipe using the ethylene-based polymer. The ethylene-based polymer satisfies the balance of mechanical characteristics and excellent molding processability, as compared with a conventional ethylene-based polymer. Also provided are an ethylene-based polymer having a wide molecular weight distribution and a small lamellar thickness, thereby increasing tie molecules and obtaining excellent long-term pressure resistance characteristics, and a pipe using the same.

A mixed metallocene catalyst system can comprise at least one metallocene catalyst compound comprising a structure represented by formula (A) below and optionally at least one other metallocene catalyst compound having a structure represented by formula (B) below: ##STR00001##
A mixed metallocene catalyst system can additionally include a non-coordinating anion type activator comprising a supported alumoxane or aluminum alkyl, and optionally a scavenger. A process for making a polymeric product can comprise: contacting a C.sub.2-C.sub.22 alpha-olefin feed with the catalyst system to obtain a polymerization reaction mixture; and obtaining a polymer product from the polymerization reaction mixture. A polymer product can be made by the process.

This invention relates to a method for producing multimodal polyolefin using multistage continuous polymerization process for producing multimodal polyolefin having superior melt-strength, moldability, mechanical strength, processability, and appearance. A method for producing multimodal polyolefin using multistage polymerization process, comprising the steps of: polymerizing a high molecular weight bimodal polymer by introducing a monomer in the presence of a catalyst composition including two or more different catalysts in a first reactor; and continuously introducing the high molecular weight bimodal polymer produced in the first reactor into a second reactor, and polymerizing a low molecular weight bimodal polymer by introducing a monomer in the presence of the catalyst composition, wherein the multimodal polyolefin includes the high molecular weight bimodal polymer and the low molecular weight bimodal polymer at the same time.

Provided is an ethylene/alpha-olefin copolymer having excellent environmental stress crack resistance.

Solid support materials are described for use as supports for olefin polymerisation catalysts. Also described is a process for the preparation of the solid support materials and the use of the solid support materials as supports in olefin polymerisation reactions.

Solid support materials are described for use as supports for olefin polymerisation catalysts. Also described is a process for the preparation of the solid support materials and the use of the solid support materials as supports in olefin polymerisation reactions.

Modified solid polymethylaluminoxanes are described for use as support materials for olefin polymerisation catalysts. The modified solid polymethylaluminoxanes have higher specific surface areas than their unmodified analogues. Also described is a process for the preparation of the modified solid polymethylaluminoxanes and the use of the modified solid polymethylaluminoxanes as support materials in olefin polymerisation reactions.

Modified solid polymethylaluminoxanes are described for use as support materials for olefin polymerisation catalysts. The modified solid polymethylaluminoxanes have higher specific surface areas than their unmodified analogues. Also described is a process for the preparation of the modified solid polymethylaluminoxanes and the use of the modified solid polymethylaluminoxanes as support materials in olefin polymerisation reactions.