Process for producing cyclic olefin based polymers, cyclic olefin copolymers, compositions and molded articles comprising the copolymers

A process for producing a cyclic olefin based polymer wherein homopolymerization of a cyclic olefin or copolymerization of a cyclic olefin and an alpha-olefin is carried out in the presence of a catalyst comprising as main components the following compounds (A) and (B):

• (A) a transition metal compound;
• (B) a compound capable of forming an ionic complex when reacted with said transition metal compound;
• and
• (C) an organoaluminum compound, wherein Compound (A) is a transition metal compound represented by the following formula:
• M.sup.1 R.sup.1 R.sup.2 R.sup.3 R.sup.4
• wherein M.sup.1 is a transition metal selected from the IVB Group of the Periodic Table;
• R.sup.1, R.sup.2, R.sup.3, and R.sup.4 may be the same as or different from each other, and are independently a ligand having a sigma bond, chelate ligand or Lewis base.

A cyclic olefin copolymer having (1) 80 to 99.9 mol % of the repeating unit [X] ##STR7## wherein R.sup.a is hydrogen or a C.sub.1-20 hydrocarbon group and 0.1 to 20 mol % of the repeating unit [Y]:

• ##STR8## wherein R.sup.b to R.sup.m, which may be the same or different from each other, are each independently hydrogen, a C.sub.1-20 hydrocarbon group or a substituent having a halogen atom, oxygen atom or nitrogen atom;
• R.sup.j or R.sup.k and R.sup.l or R.sup.m may form a ring together, and n is 0 or an integer value;
• (2) an intrinsic viscosity of 0.005 to 20 dl/g;
• (3) a glass transition temperature of less than 20.degree. C.;
• (4) a tensile modulus ranging from 300 to 2,000 kg/cm.sup.2, determined by measurement at room temperature, and (5) a molecular weight distribution M.sub.W /M.sub.n of about 1.3 to 3.