Ester compound and thermosetting resin composition using the same

An ester compound prepared by

• esterifying at least one OH group of a polyhydric phenol which is a condensation product of
• a non-substituted or substituted resorcinol represented by the following general formula (1):
• wherein P independently represents a halogen atom, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms or an aralkyl group having 7 to 20 carbon atoms;
• and i represents an integer of 0 to 2 and a carbonyl compound represented by the following general formula (2):
• wherein X and X′ independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, and X and X′ may form a ring,
• with an organic carboxylic acid having 1 to 20 carbon atoms or a derivative thereof, which necessarily contains an organic carboxylic polyacid having 1 to 20 carbon atoms or a derivative thereof, wherein a proportion of said organic carboxylic polyacid having 1 to 20 carbon atoms or a derivative thereof is within the range from 10 equivalent % to 50 equivalent %, based on the organic carboxylic acid having 1 to 20 carbon atoms or a derivative thereof used in the esterification.