The present invention provides a polybutadiene having improved workability and abrasion resistance. A polybutadiene according to the present invention has: (A) a Mooney viscosity (ML.sub.1+4,100 C.) being 43 or more; (B) a ratio (Tcp/ML.sub.1+4,100 C.) of 5 wt % toluene solution viscosity (Tcp) to Mooney viscosity (ML.sub.1+4,100 C.) being 0.9 to 2.3; (C) a stress relaxation time (T80) being 10.0 to 40.0 seconds, which is a time until a torque is attenuated by 80% when the torque at the end of ML.sub.1+4,100 C.measurement is 100%; and (D) a molecular weight distribution (Mw/Mn) being 2.50 to 4.00.

Rubber compounds that comprise rubber and propylene-a-olefin-diene (PE(D)M) polymers may be useful in tire-related articles (e.g., tire sidewalls, inner tubes, and innerliners). Such a rubber compound may comprise: about 5 phr to about 50 phr of the PE(D)M polymer that comprises about 65 wt % to about 99.5 wt % propylene, about 0.5 wt % to about 35 wt % a-olefin that is not propylene, and 0 wt % to about 20 wt % diene, said wt % based on the weight of the PE(D)M polymer, and about 50 parts per hundred parts rubber (phr) to about 95 phr of a rubber that comprises one selected from the group consisting of the halogenated isobutylene-based rubber is selected from the group consisting of: natural rubber, polyisoprene rubber, poly(styrene-co-butadiene) rubber, polybutadiene rubber, poly(isoprene-co-butadiene) rubber, styrene-isoprene-butadiene rubber, butyl rubber, star branched butyl rubber, isobutylene-isoprene rubber, poly(isobutylene-co-alkylstyrene), a halogenated isobutylene-based rubber, polychloroprene rubber, nitrile rubber, and any combination thereof.

The present invention provides a polybutadiene having improved workability and abrasion resistance. A polybutadiene according to the present invention has: (A) a Mooney viscosity (ML.sub.1+4,100 C.) being 43 or more; (B) a ratio (Tcp/ML.sub.1+4,100 C.) of 5 wt % toluene solution viscosity (Tcp) to Mooney viscosity (ML.sub.1+4,100 C.) being 0.9 to 2.3; (C) a stress relaxation time (T80) being 10.0 to 40.0 seconds, which is a time until a torque is attenuated by 80% when the torque at the end of ML.sub.1+4,100 C.measurement is 100%; and (D) a molecular weight distribution (Mw/Mn) being 2.50 to 4.00.

An elastomeric composition suitable for use in belts like transmission belts may comprise: from 5 to 100 phr of a propylene--olefin-diene (PEDM) terpolymer comprising 80 wt % to 97.5 wt % propylene, 2.5 wt % to 20 wt % a-olefin, and 0.5 wt % to 10 wt % diene, said wt % based on the weight of the PEDM terpolymer, and wherein the PEDM terpolymer has (a) Mooney viscosity (ML(1+4)) of 1 MU to 60 MU, (b) melt flow rate of 0.5 g/min to 100 g/min, and (c) a weight average molecular weight to n-average molecular weight (Mw/Mn) ratio of 1.5 to 3.0; and from 60 to 95 phr of an ethylene-based copolymer comprising 0 wt % to 95 wt % ethylene, 0 wt % to 10 wt % of one or more dienes, and 5 wt % to 60 wt % C3 to C12 -olefin, said wt % based on the total weight of the ethylene-based copolymer.

The present disclosure provides methods for producing an olefin polymer by contacting a C.sub.3-C.sub.40 olefin and ethylene with a catalyst system including an activator and a metallocene catalyst compound comprising a substituted or unsubstituted tetrahydro-s-indacenyl group and obtaining a C.sub.3-C.sub.40 olefin-ethylene copolymer typically comprising from 0.5 to 43 wt % ethylene, and from 99.5 to 57 wt % C.sub.3 to C.sub.40 comonomer wherein the Tg of the terpolymer is from 0 to 60 C.

The present invention relates to a method for preparing a liquid rubber, and relates to a method for preparing a liquid rubber, including performing polymerization reaction of a conjugated diene-based monomer in the presence of an organic solvent and a catalyst composition (S10), wherein the catalyst composition includes a catalyst including a compound represented by the following Formula 1, and a liquid rubber prepared therefrom: ##STR00001## wherein R, R.sub.1 to R.sub.4, and o, p, q and r are described herein.

An elastomeric composition is provided that includes from 1 to 100 parts by weight per hundred parts by weight rubber (phr) of a first propylene--olefin-diene (PEDM) terpolymer comprising 70 wt % to 92.5 wt % propylene, 7.5 wt % to 30 wt % a C2 or C4-C12 -olefin, and 3.5 wt % to 20 wt % diene, said wt % based on the weight of the PEDM terpolymer. The PEDM terpolymer V may have a Mooney viscosity (ML(1+4)) of 25 MU to 100 MU. The composition may further include from 0 to 99 phr of an ethylene-based copolymer comprising 40 wt % to 95 wt % ethylene.

The present invention relates to a method for preparing a liquid rubber, and relates to a method for preparing a liquid rubber, including performing polymerization reaction of a conjugated diene-based monomer in the presence of an organic solvent and a catalyst composition (S10), wherein the catalyst composition includes a catalyst including a compound represented by the following Formula 1, and a liquid rubber prepared therefrom:

##STR00001##

wherein R, R.sub.1 to R.sub.4, and o, p, q and r are described herein.

The present invention relates to a method for purifying a polyalkylaluminoxane-containing solution using a hydroxy group-containing compound, a method for producing a catalyst composition using the method, a catalyst composition produced by the production method, and a method for producing an olefin polymer using the catalyst composition.

A process for preparing a catalyst component made from or containing Mg, Ti, and at least an electron donor compound (ID), including the steps of: (a) reacting a Mg based compound with a Ti compound, having at least a TiCl bond, in an amount such that the Ti/Mg molar ratio is greater than 3 and at a temperature ranging from 0 to 150 C., thereby yielding an intermediate solid catalyst component containing Mg and Ti; and (b) contacting the intermediate solid catalyst component with a gaseous stream containing the electron donor compound (ID) in a gaseous dispersing medium, thereby yielding a final solid catalyst component having an ID/Ti molar ratio ranging from 0.5:1 to 20:1.