A production method for a cyclic olefin copolymer which is capable of efficiently producing a cyclic olefin copolymer by copolymerizing monomers including a norbornene monomer and ethylene while suppressing the formation of a polyethylene-like impurity, and a catalyst composition for the copolymerization of a norbornene monomer and ethylene. Monomers including a norbornene monomer and ethylene are polymerized in the presence of a metal-containing catalyst, and the metal-containing catalyst has a structure in which a nitrogen atom is bonded to a transition metal of Group 4 of the periodic table and an atom of Group 15 of the periodic table.

A process for the continuous synthesis of a modified diene elastomer comprising at least one silicon atom directly connected to the elastomer chain is provided. The process comprises polymerization by n reactors r1 to rn, considered to be continuous stirred-tank reactors equipped with an internal stirring system and arranged in series, n varying from 2 to 15. The reactor r1 is fed by an input solution comprising a solvent, one or more monomer(s), an anionic polymerization initiator chosen from lithium amides and a polar agent. The temperature of each reactor varies from 20° C. to 150° C. and is greater than or equal to the temperature of the reactor which immediately precedes it. The living diene elastomer obtained exhibits a polydispersity index varying from 1.1 to 1.7. The process further comprises modification of the living diene elastomer obtained in the preceding stage by a functionalization, coupling or star-branching agent.

The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in complex modulus E* over time. The present invention relates to rubber compositions containing at least one copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber compositions having a heat aging resistance index defined by equation (1) of 27 or less.

The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in complex modulus E* over time. The present invention relates to rubber compositions containing at least one copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber compositions having a heat aging resistance index defined by equation (1) of 27 or less.

The present invention relates to a modification initiator and a modified conjugated diene-based polymer including the same, and more particularly, the present invention provides a modification initiator including a compound represented by Formula 1, a modified conjugated diene-based polymer including the same, and a method of preparing a modified conjugated diene-based polymer.

The present invention relates to a modification initiator and a modified conjugated diene-based polymer including the same, and more particularly, the present invention provides a modification initiator including a compound represented by Formula 1, a modified conjugated diene-based polymer including the same, and a method of preparing a modified conjugated diene-based polymer.

The present invention provides: a novel production technique that enables production of a polymer whose molecular weight and molecular weight distribution are controlled and production of a polymer having a complicated structure in a desirably controlled manner using commercially available materials without using a radical polymerization initiator or a special material for use in living radical polymerization and without the need for strict polymerization conditions; and a radical polymerization initiating group-containing compound for use in the technique. The present invention relates to: a method for producing a polymer, the method including a polymerization step of mixing and warming (1) a radically polymerizable monomer, (2) an organic compound wherein at least one group that functions as a group for initiating polymerization of the monomer and that has a structure represented by formula 1 or formula 2 (X in the formula represents Cl or Br) is introduced in a molecule of the organic compound, and (3) an iodine-containing compound, thereby initiating, from the group having the structure, radical polymerization accompanied by a termination reaction; and the organic compound of (2) for use in the method. ##STR00001##

The present invention provides: a novel production technique that enables production of a polymer whose molecular weight and molecular weight distribution are controlled and production of a polymer having a complicated structure in a desirably controlled manner using commercially available materials without using a radical polymerization initiator or a special material for use in living radical polymerization and without the need for strict polymerization conditions; and a radical polymerization initiating group-containing compound for use in the technique. The present invention relates to: a method for producing a polymer, the method including a polymerization step of mixing and warming (1) a radically polymerizable monomer, (2) an organic compound wherein at least one group that functions as a group for initiating polymerization of the monomer and that has a structure represented by formula 1 or formula 2 (X in the formula represents Cl or Br) is introduced in a molecule of the organic compound, and (3) an iodine-containing compound, thereby initiating, from the group having the structure, radical polymerization accompanied by a termination reaction; and the organic compound of (2) for use in the method. ##STR00001##

A production method for a cyclic olefin copolymer which is capable of efficiently producing a cyclic olefin copolymer by copolymerizing monomers including a norbornene monomer and ethylene while suppressing the formation of a polyethylene-like impurity, and a catalyst composition for the copolymerization of a norbornene monomer and ethylene. Monomers including a norbornene monomer and ethylene are polymerized in the presence of a metal-containing catalyst, and the metal-containing catalyst has a structure in which a nitrogen atom is bonded to a transition metal of Group 4 of the periodic table and an atom of Group 15 of the periodic table.

A method for preparing a 2-cyanoethyl group-containing polymer is provided. The method can prepare a purified 2-cyanoethyl group-containing polymer with high purity even while a reduced amount of water was used during the purification process, thus reducing the amount of wastewater generated.