Epoxy Resin Composition

An epoxy resin composition comprising:

• (A) an epoxy resin containing two or more epoxy groups in a molecule;
• (B) a urethane bond-containing polyorganosiloxane represented by the following formula (1):
• wherein, R1 each independently represents a group selected from an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms, or a hydroxy group, X is each independently a divalent alkylene group having 1 to 10 carbon atoms, Y is each independently a group selected from an alkylene group having 5 to 30 carbon atoms and optionally having an ether bond, an arylene group having 6 to 30 carbon atoms, and an aralkylene group having 7 to 30 carbon atoms, Z is each independently an alkylene group having 1 to 20 carbon atoms and optionally having an ether bond, “n” is an integer from 0 to 100, and “m” is 1 to 10;
• (C) a mesogenic group-containing polyorganosiloxane represented by the following formula (2):
• wherein, R1 each independently represents a group selected from an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms, or a hydroxy group, “p” represents a repeating unit of a siloxane structure and is an integer from 0 to 100, and R2 each independently represents the following formula (3) or formula (4):
• wherein, R3 and R4 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, L is a linking group to the formula (2) and is a divalent hydrocarbon group having 1 to 12 carbon atoms, “a” and “b” represent the number of substituents of phenyl group in the formulae (3) and (4) and are integers from 0 to 4, and G is a glycidyl ether group;
• and
• (D) an epoxy resin curing agent.