Abstract: A transparent article is obtained by molding a cyclic olefin copolymer or a resin composition containing the cyclic olefin copolymer. The cyclic olefin copolymer is obtained by a process that at least includes a step of preparing a norbornene monomer and ethylene as monomers in a polymerization vessel and a step of polymerizing the monomers in the polymerization vessel in the presence of a metal-containing catalyst. The metal-containing catalyst satisfies predetermined conditions.

Abstract: 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. The monomers including a norbornene monomer and ethylene are polymerized in the presence of a metallocene catalyst containing a cyclopentadiene ligand which is substituted with an alkyl group optionally substituted with a halogen atom, or a trialkylsilyl group, and satisfies specific conditions for substituent(s).

Abstract: 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.

Abstract: 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.