Patent ID: 7326520

Claim:
A copolymer consisting of repeating units l, m, n and o represented by the following Formula 1: wherein R 1 , R 2 and R 3 are independent to one another; R 1 is hydrogen, C 1 -C 18 alkyl, C 3 -C 18 cycloalkyl, C 2 -C 18 alkoxyalkyl, or C 3 -C 18 cycloalkoxyalkyl; R 2 and R 3 are hydrogen, or C 1 -C 30 alkyl with or without an ether group, an ester group, a carbonyl group, an acetal group, an epoxy group, a nitrile group, or an aldehyde group; R 4 and R 5 are independently hydrogen or methyl; X is an olefin compound representing a norbornene derivative; and l, m, n and o are a repeat unit of the copolymer, where l+m+n+o=1, 0.1</(l+m+n+o)<0.8, 0.1<m/(l+m+n+o)<0.7, 0.1<n/(l+m+n+o)<0.7, and 0.1<o/(l+m+n+o)<0.5.