A polyethylene powder having a limiting viscosity [η] of 2.0 dl/g or more and less than 20.0 dl/g as measured in decalin at 135° C., wherein the polyethylene powder presents a percentage decrease from a specific surface area A measured by the BET method before heating at 120° C. for 5 h to a specific surface area B measured by a BET method after heating at 120° C. for 5 h, ((A−B)/A×100), of 0.1% or more and less than 35%.

Ethylene-based polymers are characterized by a density from 0.92 to 0.955 g/cm.sup.3, a HLMI of less than 35 g/10 min, and a ratio of a number of short chain branches (SCBs) per 1000 total carbon atoms at Mz to a number of SCBs per 1000 total carbon atoms at Mn in a range from 11.5 to 22. These polymers can have a higher molecular weight (HMW) component and a lower molecular weight (LMW) component, in which a ratio of a number of SCBs per 1000 total carbon atoms at Mn of the HMW component to a number of SCBs per 1000 total carbon atoms at Mn of the LMW component is in a range from 10.5 to 22. These ethylene polymers can be produced using a dual catalyst system containing an unbridged metallocene compound with an indenyl group having at least one halogen-substituted hydrocarbyl substituent with at least two halogen atoms, and a single atom bridged metallocene compound with a fluorenyl group and a cyclopentadienyl group.

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.

The present invention relates to a method for producing a catalyst component for olefin polymerization, the method including step (3): granulating, by a spray drying, an aqueous slurry of an ion-exchangeable second layered silicate (B) that satisfies that an average particle diameter is 0.03 μm to 0.4 μm, and a Rosin-Rammler distribution constant n determined from a particle size distribution is 1.5 or more; and step (4): bringing the obtained first layered silicate granulated particles (C) into contact with acid to obtain chemically treated ion-exchangeable second layered silicate granulated particles (D).

Provided are a hybrid supported metallocene catalyst comprising one or more first metallocene compounds selected from compounds represented by the following Chemical Formula 1; one or more second metallocene compounds selected from compounds represented by the following Chemical Formula 2, and showing high activity in propylene polymerization and being usefully applied to the preparation of a polypropylene having high melt strength by introducing long chain branches into the polypropylene molecule, and a method of preparing a polypropylene using the same

##STR00001## wherein all the variables are described herein.

The present disclosure relates to a polypropylene resin exhibiting excellent processability and capable of producing fine fibers, a polypropylene fiber including the same, and a method for preparing the same.

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 comprises the following formula:

##STR00001##

wherein each R.sup.3 or R.sup.4 is independently H, a hydrocarbyl group, a substituted hydrocarbyl group, or a heteroatom group, wherein each R.sup.3 or R.sup.4 may be the same or different, and each X is independently a leaving group selected from a labile hydrocarbyl, a substituted hydrocarbyl, a heteroatom group, or a divalent radical that links to an R.sup.3 group.

A copolymer of ethylene and of a 1,3-diene of formula CH.sub.2═CR—CH═CH.sub.2 is provided. The ethylene units represent between 50 mol % and 95 mol % of the ethylene units and of the units of the 1,3-diene, and the units of the 1,3-diene of 1,2 and 3,4 configuration represent more than 50 mol % of the units of the 1,3-diene. The symbol R represents a hydrocarbon chain having from 3 to 20 carbon atoms. Such a copolymer exhibits an improved compromise between the degree of crystallinity and the stiffness and makes it possible to widen the field of application of ethylene-rich diene copolymers in rubber compositions.

The present invention relates to a high-melt-strength polypropylene resin, and a preparation method therefor. A method for preparing the high-melt-strength polypropylene resin, according to the present invention, comprises the steps of: creating a polypropylene by polymerizing propylene monomers in the presence of a metallocene catalyst; and putting a diene compound and a comonomer into the created polypropylene and unreacted propylene monomers and reacting same, thereby forming a C40 or greater long-chain branch on the main chain of the polypropylene.

The present invention relates to a semi-crystalline functionalized olefin copolymer composition and a process for the preparation of a semi-crystalline functionalized olefin copolymer composition.