Norbornene copolymer and production method thereof

1. A norbornene copolymer comprising a monomer unit represented by formula (1) and formula (2)

and having a number average molecular weight (Mn) of 300,000 to 2,000,000;

in the formulae, R 1 , represents an alkyl group having 1 to 10 carbon atoms; and R 2 , R 3 and R 4 independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

2. The norbornene copolymer as claimed in claim 1 comprising a monomer unit represented by formula (1) and formula (2) only.

3. The norbornene copolymer as claimed in claim 1 having a molecular weight distribution (Mw/Mn) of 1.0 to 2.5.

4. The norbornene copolymer as claimed in claim 1 , wherein R 1 in formula (1) is a methyl group.

5. The norbornene copolymer as claimed in claim 1 , wherein R 2 in formula (1) and R 3 and R 4 in formula (2) is a hydrogen atom.

6. The norbornene copolymer as claimed in claim 1 , comprising the monomer unit represented by formula (1) in an amount of 10 to 70 mol %.

7. A method for producing the norbornene copolymer as claimed in claim 1 characterized in using a catalyst comprising the following main catalyst (A), cocatalyst (B) and phosphine ligand (C):

main catalyst (A):

a complex represented by formula (3)

ML n K1 x K2 y K3 z   (3)

(In the formula, M represents one transition metal selected from the elements belonging to eight, nine or ten group of the periodic table; L represents cyclopentadienyl ligand comprising cyclopentadienyl or a derivative thereof; K1, K2 and K3 represent an anionic ligand or a neutral ligand which are different from each other; n is an integer of 1 to 3; x, y and z are 0 or an integer the total of which comes to 1 to 7)

cocatalyst (B):

at least one compound selected from an organic aluminum compound (a), an ionic compound (b) capable of producing a cationic transition metal compound through the reaction with the main catalyst (A) and a compound (c) promoting the release of the ligand in the complex constituting the main catalyst (A),

phosphine ligand (C).

8. A method for producing the norbornene copolymer as claimed in claim 7 , wherein in formula (3) representing a main catalyst (A) M is nickel or palladium; L is cyclopentadienyl; and K1, K2 and K3 independently represent methyl group or allyl group.

9. A method for producing the norbornene copolymer as claimed in claim 8 , wherein the main catalyst (A) is cyclopentadienyl(π-allyl)palladium.

10. A method for producing the norbornene copolymer as claimed in claim 7 , wherein the cocatalyst (B) is tris(pentafluorophenyl)boron, trityltetrakis(pentafluorophenyl)borate or N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate.

11. The norbornene copolymer as claimed in claim 2 having a molecular weight distribution (Mw/Mn) of 1.0 to 2.5.

12. The norbornene copolymer as claimed in claim 2 , wherein R 1 in formula (1) is a methyl group.

13. The norbornene copolymer as claimed in claim 2 , wherein R 2 in formula (1) and R 3 and R 4 in formula (2) is a hydrogen atom.

14. The norbornene copolymer as claimed in claim 2 , comprising the monomer unit represented by formula (1) in an amount of 10 to 70 mol %.