A process for preparing a polydiene, the process comprising (i) forming an active catalyst composition by combining a rare-earth compound, an alkylating agent, an aluminoxane, and a halogen compound; and (ii) combining the active catalyst composition with monomer to be polymerized within 12 hours of forming the active catalyst composition.

A modified conjugated diene-based polymer represented by Formula 1, wherein a terminal of a polymer chain is modified, and a method for preparing same are provided. By including a modifier derived unit having a specific structure, a beta value affecting cold flow may be reduced through controlling the degree of branch, and accordingly, the cold flow of a polymer may be efficiently controlled and a mooney viscosity increasing ratio may be improved.

A modified conjugated diene-based polymer represented by Formula 1, wherein a terminal of a polymer chain is modified, and a method for preparing same are provided. By including a modifier derived unit having a specific structure, a beta value affecting cold flow may be reduced through controlling the degree of branch, and accordingly, the cold flow of a polymer may be efficiently controlled and a mooney viscosity increasing ratio may be improved.

The object of the invention is to provide a novel olefin-based molded product useful for various applications. An olefin-based molded product comprising a polymer including a structural unit of at least one polar olefin monomer represented by the general formula (I) CH.sub.2═CH—R.sup.2—Z(R.sup.1).sub.n is provided. In the formula, Z is a hetero atom selected from the group consisting of nitrogen, oxygen, phosphorus, sulfur, and selenium; R.sup.1 is a substituted or unsubstituted hydrocarbyl group having 1 to 30 carbon atoms; n is an integer of 1 or 2 depending on the atomic species of Z; and R.sup.2 is a substituted or unsubstituted hydrocarbylene group having 2 to 20 carbon atoms.

The object of the invention is to provide a novel olefin-based molded product useful for various applications. An olefin-based molded product comprising a polymer including a structural unit of at least one polar olefin monomer represented by the general formula (I) CH.sub.2═CH—R.sup.2—Z(R.sup.1).sub.n is provided. In the formula, Z is a hetero atom selected from the group consisting of nitrogen, oxygen, phosphorus, sulfur, and selenium; R.sup.1 is a substituted or unsubstituted hydrocarbyl group having 1 to 30 carbon atoms; n is an integer of 1 or 2 depending on the atomic species of Z; and R.sup.2 is a substituted or unsubstituted hydrocarbylene group having 2 to 20 carbon atoms.

A terpolymer of ethylene, of a first 1,3-diene having from 4 to 6 carbon atoms and of a second 1,3-diene of formula CH.sub.2═CR-CH═CH.sub.2 is provided. The terpolymer contains more than 50 mol % of ethylene units and at least 1 mol % of units of the second 1,3-diene, the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms. Such a polymer gives an improved compromise between its ethylene content, its stiffness and its degree of crystallinity for use in tires.

To provide a method for producing a multicomponent copolymer with which a multicomponent copolymer having excellent rupture strength can be obtained, and a multicomponent copolymer, a rubber composition and a tire having excellent rupture strength. The method is a method for producing a multicomponent copolymer having a conjugated diene unit, a non-conjugated olefin unit and an aromatic vinyl unit, comprising adding a conjugated diene compound in divided portions into a reactor containing a catalyst and at least one selected from the group consisting of a non-conjugated olefin compound and an aromatic vinyl compound. The multicomponent copolymer is obtained with the production method. The rubber composition comprises the multicomponent copolymer as a rubber component. The tire uses the rubber composition.

To provide a method for producing a multicomponent copolymer with which a multicomponent copolymer having excellent rupture strength can be obtained, and a multicomponent copolymer, a rubber composition and a tire having excellent rupture strength. The method is a method for producing a multicomponent copolymer having a conjugated diene unit, a non-conjugated olefin unit and an aromatic vinyl unit, comprising adding a conjugated diene compound in divided portions into a reactor containing a catalyst and at least one selected from the group consisting of a non-conjugated olefin compound and an aromatic vinyl compound. The multicomponent copolymer is obtained with the production method. The rubber composition comprises the multicomponent copolymer as a rubber component. The tire uses the rubber composition.

Vulcanizates with desirable properties such as reduced hysteresis and improved wear resistance can be obtained from a composition that includes particulate filler(s) and at least two types of terminally functionalized polymers. One type of polymer has a heterocyclic moiety at a terminus, while another type has at one of its termini an aryl group that includes at least two hydroxyl substituents. The functionalized polymers are provided by reacting terminally active polymers with, respectively, a heterocyclic nitrile and a compound that includes an aryl group having at least two directly bonded OG.sub.p substituents, where G.sub.p is a protecting group, and a substituent that can react with the active terminus. The protecting groups can be removed so as to provide a terminal moiety that includes an aryl group having at least two directly bonded hydroxyl groups.

Vulcanizates with desirable properties such as reduced hysteresis and improved wear resistance can be obtained from a composition that includes particulate filler(s) and at least two types of terminally functionalized polymers. One type of polymer has a heterocyclic moiety at a terminus, while another type has at one of its termini an aryl group that includes at least two hydroxyl substituents. The functionalized polymers are provided by reacting terminally active polymers with, respectively, a heterocyclic nitrile and a compound that includes an aryl group having at least two directly bonded OG.sub.p substituents, where G.sub.p is a protecting group, and a substituent that can react with the active terminus. The protecting groups can be removed so as to provide a terminal moiety that includes an aryl group having at least two directly bonded hydroxyl groups.