Patent ID: 8563770

Claim:
A polynuclear polyphenol compound expressed by general formula (2) below: wherein R 1 and R 2 each independently represent an alkyl group with 1 to 8 carbon atoms or alkoxyl group with 1 to 8 carbon atoms, R 3 is an aliphatic saturated hydrocarbon group with 1 to 8 carbon atoms that may have a single-ring or condensed-ring aromatic hydrocarbon group with 6 to 15 carbon atoms, R 4 is a hydrogen atom or primary alkyl group or secondary alkyl group with 1 to 6 carbon atoms, R 5 and R 6 may be the same or different and each represent a bivalent aliphatic saturated hydrocarbon group with 1 to 8 carbon atoms, m is an integer of 0 or 1 to 3, n is an integer of 0 or 1 to 3, and k is an integer of 1 to 3, but if k is 2 or greater, then R 6 , R 1 and n in each phenyl group may all be the same or different, and X is a hydroxyphenyl group expressed by general formula (3) below: wherein R 7 is an alkyl group with 1 to 8 carbon atoms or alkoxyl group with 1 to 8 carbon atoms, a is an integer of 1 to 3, b is an integer of 0 to 4, where 1≦a+b≦5, and if b is 2 or greater, then R 7 's may be the same or different.