EPOXY RESIN B-STAGE FILM, EPOXY RESIN CURED FILM AND METHOD OF PRODUCING EPOXY RESIN CURED FILM
An epoxy resin B-stage film obtained by semi-curing an epoxy resin composition, the epoxy resin composition including: a liquid crystalline epoxy monomer capable of forming a cured product that includes a liquid crystal structure; and a curing agent, in which the epoxy resin B-stage film has an average thickness of less than 8 μm, and in which the liquid crystal structure included in the cured product turns into a liquid crystal structure, in which molecules are orientated in a film thickness direction, by being cured.
1 . An epoxy resin cured film, comprising a liquid crystal structure in which molecules are orientated in a film thickness direction, and which has an average thickness of less than 8 μm.
2 . The epoxy resin cured film according to claim 1 , wherein the liquid crystal structure is a nematic structure or a smectic structure.
3 . The epoxy resin cured film according to claim 1 , comprising a cured product of an epoxy resin composition, the epoxy resin composition comprising: a liquid crystalline epoxy monomer capable of forming a cured product that includes a liquid crystal structure; and a curing agent.
4 . The epoxy resin cured film according to claim 3 , wherein the liquid crystalline epoxy monomer comprises a monomer 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.
5 . The epoxy resin cured film according to claim 4 , wherein the liquid crystalline epoxy monomer comprises a reaction product of the monomer represented by Formula (I) and at least one selected from the group consisting of hydroquinone and a biphenol.
6 . The epoxy resin cured film according to claim 3 , wherein the curing agent comprises an amine curing agent.
7 . The epoxy resin cured film according to claim 3 , wherein the epoxy resin composition further comprises a solvent.
8 . The epoxy resin cured film according to claim 3 , wherein a content of the liquid crystalline epoxy monomer with respect to a total solid content of the epoxy resin composition is from 5% by volume to 80% by volume.
9 . The epoxy resin cured film according to claim 4 , wherein the monomer represented by Formula (I) comprises at least one selected from the group consisting of 4-{4-(2,3-epoxypropoxy)phenyl}cyclohexyl=4-(2,3-epoxypropoxy)benzoate and 4-{4-(2,3-epoxypropoxy)phenyl}cyclohexyl=4-(2,3-epoxypropoxy)-3-methyl benzoate.
10 . The epoxy resin cured film according to claim 5 , wherein the biphenol is 4,4′-biphenol.
11 . The epoxy resin cured film according to claim 6 , wherein the amine curing agent is 3,3′-diaminodiphenyl sulfone.
12 . A method of producing the epoxy resin cured film according to claim 1 , the method comprising:
forming a film having an average thickness of less than 8 μm at a temperature of 150° C. or lower, using an epoxy resin composition comprising: a liquid crystalline epoxy monomer capable of forming a cured product that includes a liquid crystal structure; and a curing agent; and
curing the film at a curing temperature of 200° C. or lower.