Patent ID: 8450440

Claim:
A method for purifying a polymer in which a solution comprising a cyclic olefin polymer containing at least a repeating structural unit represented by the general formula (1) and a metal component is brought into contact with an organic compound containing a basic functional group and an acidic functional group, and then said solution is brought into contact with a basic adsorbent to remove the metal component contained in said solution, wherein, in the formula, at least one of R 1 to R 4 is selected from alkoxycarbonyl having 2 to 20 carbon atoms, alkoxyalkyloxycarbonyl having 3 to 20 carbon atoms, alkoxycarbonylalkyloxycarbonyl having 4 to 20 carbon atoms and cyano having 1 to 20 carbon atoms, the others are selected from hydrogen, alkyl having 1 to 20 carbon atoms, halogen, alkyl halide having 1 to20 carbon atoms, alkoxy having 1 to 20 carbon atoms, alkoxyalkyl having 2 to 20 carbon atoms and aryloxycarbonyl having 6 to 20 carbon atoms, and R 1 to R 4 may be bonded to each other to form a cyclic structure; X 1 is selected from —O—, —S—, —NR 5 —, —PR 5 —and —CR 5 R 6 —(R 5 and R 6 each independently represent hydrogen or alkyl having 1 to 20 carbon atoms) and may be the same or different from each other; and j represents 0 or 1.