Epoxy resin, epoxy resin composition, epoxy resin cured product, and composite material
An epoxy resin, comprising an epoxy compound having a mesogenic structure, the epoxy compound comprising a first epoxy compound having one biphenyl structure in a molecule and a second epoxy compound that is different from the first epoxy compound, at a mass ratio of the first epoxy compound to the second epoxy compound (first epoxy compound:second epoxy compound) of from 10:100 to 50:100.
1. An epoxy resin, comprising an epoxy compound having a mesogenic structure,
the epoxy compound comprising a first epoxy compound having one biphenyl structure in a molecule and a second epoxy compound that is different from the first epoxy compound, at a mass ratio of the first epoxy compound to the second epoxy compound (first epoxy compound: second epoxy compound) of from 10:100 to 50:100,
wherein the second epoxy compound comprises an epoxy compound having one mesogenic structure and an epoxy compound having two or more mesogenic structures each represented by the following Formula (B):
wherein, in Formula (B), X represents a linking group comprising at least one divalent group having the following structure:
each Y independently represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an aliphatic alkoxy group having 1 to 8 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group or an acetyl group; and each n independently represents an integer from 0 to 4.
2. The epoxy resin according to claim 1 , wherein the first epoxy compound comprises an epoxy compound represented by the following Formula (A):
wherein, in Formula (A), each Z independently represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, an aliphatic alkoxy group having 1 to 8 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group or an acetyl group; and each n independently represents an integer from 0 to 4.
3. The epoxy resin according to claim 1 , wherein the mass ratio of the first epoxy compound to the second epoxy compound (first epoxy compound: second epoxy compound) is from 10:100 to 25:100.
4. The epoxy resin according to claim 1 , having a viscosity at 60 ° C. of less than 200 Pa·s.
5. An epoxy resin composition, comprising the epoxy resin according to claim 1 and a curing agent.
6. The epoxy resin composition according to claim 5 , wherein the curing agent comprises an amine compound having a benzene ring or a naphthalene ring.
7. The epoxy resin composition according to claim 6 , wherein the amine compound has an amino group that is directly bonded to the benzene ring or the naphthalene ring.
8. The epoxy resin composition according to claim 5 , having a crosslink density of 7 mmol/cm 3 or less when the epoxy resin composition is cured.
9. The epoxy resin composition according to claim 5 , having a fracture toughness of 1.2 MPa·m 1/2 or more when the epoxy resin composition is cured.
10. A cured epoxy resin obtained by curing the epoxy resin composition according to claim 5 .
11. A composite material, comprising the cured epoxy resin according to claim 10 and a reinforcing material.
12. The composite material according to claim 11 , having a structure configured by layering at least a cured product-containing layer, comprising the cured epoxy resin, and at least one reinforcing material-containing layer, comprising the reinforcing material.
13. The epoxy resin according to claim 1 , wherein X of the epoxy compound represented by Formula (B) further comprises a divalent group having the following structure:
14. The epoxy resin according to claim 1 , wherein the epoxy compound represented by Formula (B) comprises one or more structures represented by the following formula (I):
wherein, in Formula (I), each of R 1 to R 4 independently represents a hydrogen atom or an alkyl group having from 1 to 3 carbon atoms.