Abstract: The present invention relates to a resin composition, comprising (a) an epoxy resin; (b) a curing agent comprising the structure of formula C1; (c) an inorganic filler; wherein RC1 is (a) a siloxane group of formula C1a or (b) or both a siloxane group of formula C1a and an ester group of formula C1b; RC2 is selected from a bulky C4 to C12 alkyl group comprising at least one tertiary or quaternary carbon atom; RC11, RC12, RC13 are independently selected from methyl, ethyl and 1-propyl; RC14 is selected from a linear or branched C1 to C8 alkyl; XC1 is selected from a divalent C1 to C4 alkanediyl group; and n is an average number of repeating units and is from 1.05 to 200.