Patent ID: 7833694

Claim:
A lactone-containing compound having the general formula (1): wherein R 1 is hydrogen, fluorine, methyl or trifluoromethyl, R 2 and R 3 are each independently hydrogen or a straight, branched or cyclic monovalent hydrocarbon group of 1 to 10 carbon atoms, or R 2 and R 3 may bond together to form an aliphatic hydrocarbon ring with the carbon atom to which they are attached, R 4 is hydrogen or CO 2 R 5 , R 5 is a straight, branched or cyclic monovalent hydrocarbon group of 1 to 15 carbon atoms which may have a halogen or oxygen atom, W is CH 2 , O or S, with the proviso that R 4 is CO 2 R 5 when W is CH 2 , and R 4 is hydrogen or CO 2 R 5 when W is O or S, and k 1 is an integer of 3 to 5.