The present invention provides a compound represented by general formula (I) (wherein Ra0 represents a hydrogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkenyl group having 3 to 12 carbon atoms; Ra1, Ra2, Ra3 and Ra4 independently represent an alkyl group having 1 to 8 carbon atoms, or Ra1 and Ra2 and/or Ra3 and Ra4 may together form a cyclic structure; Ra5 and Ra6 independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; n represents 0 or 1; t represents 1 to 4; and U represents an organic group which can form a cyclic structure and has a valency of 2 × t).
