Abstract: Provided is a new compound which can provide a cured film obtained from a resin composition with low cure shrinkage while suppressing reduction of hardness (scratch resistance) thereof. A silsesquioxane derivative having a radically polymerizable functional group, which is represented by formula (1), (2) or (3). In the formulas (1) to (3), R1 is a group independently selected from alkyl having 1 to 45 carbons, cycloalkyl having 4 to 8 carbons, aryl having 6 to 14 carbons and arylalkyl having 7 to 24 carbons, R2 and R3 are a group independently selected from alkyl having 1 to 10 carbons, cyclopentyl, cyclohexyl and phenyl, and X is independently hydrogen or a monovalent organic group, in which at least one of X is a radically polymerizable functional group represented by formula (4).

Abstract: A silicon compound is described, being obtained by a hydrosilylation reaction of the following compound (a), compound (b) and compound (c). Compound (a) is a silsesquioxane derivative having two or more SiH in one molecule. Compound (b) is a compound having, in one molecule, epoxy and/or oxetanyl and an alkenyl having a carbon number of 2 to 18. Compound (c) is a compound having, in one molecule, an alkoxysilyl and an alkenyl having a carbon number of 2 to 18.

Abstract: A silicon compound is described, being obtained by a hydrosilylation reaction of the following compound (a), compound (b) and compound (c). Compound (a) is a silsesquioxane derivative having two or more SiH in one molecule. Compound (b) is a compound having, in one molecule, epoxy and/or oxetanyl and an alkenyl having a carbon number of 2 to 18. Compound (c) is a compound having, in one molecule, an alkoxysilyl and an alkenyl having a carbon number of 2 to 18.