Epoxy resin, epoxy resin composition, epoxy resin cured product and composite material
An epoxy resin, comprising an epoxy compound having a mesogenic structure, and having a value of η′2/η′1 equal to 3 or less, wherein η′1 is an initial dynamic shear viscosity (Pa·s) and η′2 is a maximum value of dynamic shear viscosity (Pa·s), in a measurement of dynamic shear viscosity.
1. An epoxy resin, comprising an epoxy compound having a mesogenic structure, and having a value η′2/η′1 equal to 3 or less, wherein η′1 is an initial dynamic shear viscosity in Pa·s and η′2 is a maximum value of dynamic shear viscosity in Pa·s, in a measurement of dynamic shear viscosity,
wherein the initial dynamic shear viscosity η′1 and the maximum value of dynamic shear viscosity η′2 are measured with a rheometer, with a gap between a parallel plate and a stage of the rheometer of 0.05 mm, a frequency of 0.5 Hz, a strain of 8000%, and a constant temperature of 80° C., over 80 minutes in a continuous manner, and
wherein the epoxy compound is represented by the following Formula (1):
wherein, in Formula (1), each of R 1 , R 2 and R 3 independently represents a monovalent group, at least one of the monovalent groups represented by R 1 , R 2 and R 3 includes a mesogenic structure, and at least one of the monovalent groups represented by R 1 , R 2 and R 3 has an epoxy group.
2. The epoxy resin according to claim 1 , comprising an epoxy compound A having two or more mesogenic structures and at least one phenylene group, and an epoxy compound B having two or more mesogenic structures and at least one divalent biphenyl group.
3. The epoxy resin according to claim 1 , comprising an epoxy compound having two aromatic rings that form a divalent biphenyl structure, and having mesogenic structures that are independently bonded to each of the two aromatic rings, wherein at least one of the mesogenic structures is bonded to the aromatic ring at an angle to the molecular axis of the biphenyl structure.
4. The epoxy resin according to claim 1 , wherein the initial dynamic shear viscosity η′1 is 200 Pa·s or less.
5. An epoxy resin composition, comprising the epoxy resin according to claim 1 , and a curing agent.
6. An epoxy resin cured product obtained by curing the epoxy resin composition according to claim 5 .
7. A composite material, comprising the epoxy resin cured product according to claim 6 , and a reinforcing member.