Provided is a method of producing a multicomponent copolymer, in which ethylene, a non-conjugated olefin compound having 3 to 10 carbon atoms, and a conjugated diene compound are copolymerized to produce a multicomponent copolymer. The method of producing a multicomponent copolymer is a method in which ethylene, a non-conjugated olefin compound having 3 to 10 carbon atoms, and a conjugated diene compound are copolymerized to produce a multicomponent copolymer, including a step of copolymerizing the ethylene, the non-conjugated olefin compound, and the conjugated diene compound, in the presence of a polymerization catalyst composition containing a rare earth element compound (component (A)) represented by predetermined formula.

The present disclosure relates to a novel transition metal compound of the following Chemical Formula 1, which exhibits high hydrogen reactivity with excellent catalytic activity for propylene polymerization, and is useful in the preparation of a polypropylene having a narrow molecular weight distribution and a low melting point, a catalyst composition including the same, and a method for preparing a polypropylene using the same,

##STR00001## wherein M, X.sup.1, X.sup.2, R.sup.1 to R.sup.9 are described herein.

Provided is a tetraarylborate compound, a catalyst composition including the same, and a method for preparing an ethylene homopolymer or an ethylene-α-olefin copolymer using the same. Specifically, the teraarylborate compound having excellent thermal stability, able to be completely dissolved in an aliphatic hydrocarbon-based solvent to facilitate the operation of commercial processes and effectively inducing the activation of a single active site catalyst, may be used as a catalyst activator to provide an ethylene-based copolymer selected from a high molecular weight ethylene homopolymer and ethylene-α-olefin copolymer having high catalyst activity.

The present disclosure relates to a crosslinked polyethylene pipe having excellent physical properties. The crosslinked polyethylene pipe according to the present disclosure has optimized the degree of crosslinking and storage modulus by finding out the optimum physical property range between the degree of crosslinking and the storage modulus which have a mutual trade-off relationship, whereby the crosslinked polyethylene pipe according to the present disclosure has excellent long-term durability and short-term pressure resistance, and thus can be applied to various fields requiring these physical properties.

The present disclosure provides bridged metallocene catalyst compounds including at least two —Si—Si— bridges, catalyst systems including such compounds, and uses thereof. Catalyst compounds of the present disclosure can be hafnium-containing compounds having one or more cyclopentadiene ligand(s) substituted with one or more silyl neopentyl groups and linked with at least two Si—Si-containing bridges. In another class of embodiments, the present disclosure is directed to polymerization processes to produce polyolefin polymers from catalyst systems including one or more olefin polymerization catalysts, at least one activator, and an optional support.

Provided are a hybrid supported catalyst which includes two or more kinds of transition metal compounds having the following Chemical Formulas 1 and 2, thereby preparing a polyolefin, particularly, a high-density polyethylene having a molecular structure which is optimized to improve tensile strength of a chlorinated polyolefin compound, and a method of preparing a polyolefin using the same:

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

The present invention relates to a novel metallocene catalyst compound for the production of a polyolefin resin having a high molecular weight and a wide molecular weight distribution or a method of preparing the same, and more particularly to a metallocene catalyst compound using a ligand containing a Group 15 or 16 element having a bulky substituent or a method of preparing the same. The present invention provides a novel metallocene catalyst compound represented by Chemical Formula 1 below.
(L.sup.1){(N-L.sup.2)Z.sup.1(Y)Z.sup.2(N-L.sup.3)}(X)M  [Chemical Formula 1]

A complex of formula (I): (I′) M is Hf; each X is a sigma ligand; L is a bridge of formula -(ER.sup.8.sub.2).sub.y—; y is 1 or 2; E is C or Si; each R.sup.8 is independently a C.sub.1-C.sub.20-hydrocarbyl, tri(C.sub.1-C.sub.20-alkyl)silyl, C.sub.6-C.sub.20- aryl, C.sub.7-C.sub.20-arylalkyl or C.sub.7-C.sub.20-alkylaryl or L is an alkylene group such as methylene or ethylene; Ar and Ar′ are each independently an aryl or heteroaryl group optionally substituted by 1 to 3 groups R.sup.1 or R.sup.1′ respectively; R.sup.1 and R.sup.1′ are each independently the same or can be different and are a linear or branched C.sub.1-C.sub.6-alkyl group, C.sub.7-20 arylalkyl, C.sub.7-20 alkylaryl group or C.sub.6-20 aryl group with the proviso that if there are four or more R.sup.1 and R.sup.1′ groups present in total, one or more of R.sup.1 and R.sup.1′ is other than tert butyl; R.sup.2 and R.sup.2′ are the same or are different and are a CH.sub.2—R.sup.9 group, with R.sup.9 being H or linear or branched C.sub.1-C.sub.6-alkyl group, C.sub.3-8 cycloalkyl group, C.sub.6-10 aryl group; each R is a —CH.sub.2—, —CHRx- or C(Rx).sub.2-group wherein Rx is C.sub.1-4 alkyl and where m is 2-6; R.sup.5 is a linear or branched C.sub.1-C.sub.6-alkyl group, C.sub.7-20 arylalkyl, C.sub.7-20 alkylaryl group or C.sub.6-C.sub.20-aryl group; R.sup.6 is a C(R.sup.10).sub.3 group, with R.sup.10 being a linear or branched C.sub.1-C.sub.6 alkyl group; and R.sup.6 and R.sup.7′ are the same or are different and are H or a linear or branched C.sub.1-C.sub.6-alkyl group. Invention relates also to a catalyst in solid form comprising (i) a complex of formula (I) and (ii) a cocatalyst of an aluminium compound and (iii) a cocatalyst of a boron compound.

##STR00001##

This invention relates to a polyethylene composition, and films therefrom, comprising at least 65 wt % ethylene derived units and from 0.1 to 35 wt % of C.sub.3-C.sub.12 olefin comonomer derived units, where the polyethylene composition has: a) an RCI,m of less than 85 kg/mol; b) a Tw.sub.1−Tw.sub.2 value of from −15 to −40° C.; and c) an Mw.sub.1/Mw.sub.2 value of less than 1.5 where the film has a) a heat seal initiation temperature of X ° C. or less at 5 N of force, where X=0.0015×Y(psi)+62.6 (where Y is the average 1% Secant modulus ((MD+TD)/2)) of the film; b) a dart drop impact of 300 g/mil or more; c) an MD Elmendorf tear of 230 g or more; and d) average 1% Secant modulus ((MD+TD)/2) of 20,000 psi or more.

The present invention relates to a process for producing a propylene polymer, such as a propylene homopolymer, a propylene-ethylene random copolymer or a heterophasic propylene copolymer using a specific class of metallocene complexes in combination with a cocatalyst system comprising a boron containing cocatalyst and an aluminoxane cocatalyst, preferably in a multistage polymerization process including a gas phase polymerization step.