Epoxy resin compositions, prepreg, and fiber-reinforced composite materials

An epoxy resin compositions which comprises:

• (A) at least 20 PHR in total per 100 PHR of total epoxy resin of at least one poly-naphthalene-based epoxy resin having Formula (I):
• wherein R1 to R12 are each independently selected from the group consisting of hydrogen atoms, halogen atoms, C1 to C10 alkyl groups, C1 to C10 alkoxyl groups, C1 to C10 fluoroalkyl groups, cycloalkyl groups, aryl groups, aryloxyl groups, and glycidoxy groups, Y1 to Y3 are each independently selected from the group consisting of hydrogen atoms, halogen atoms, C1 to C10 alkyl groups, C1 to C10 alkoxyl groups, C1 to C10 fluoroalkyl groups, cycloalkyl groups, aryl groups, aryloxyl groups, and glycidoxy groups, wherein each benzene nucleus may be substituted with one or more Y groups, n is 0 or an integer of 1 to 5, k is 0 or an integer of 1 to 3, wherein the Y groups may be attached to either or both rings of each naphthalene nucleus;
• and each X is independently selected from the group consisting of a direct bond, —CH2—, —C(CH3)2—, —S—, —SO2—, —O—, —C(═O)O—, —C(═O)—, —C(═O)NH—, C1 to C6 alkylene groups, C1 to C6 alkoxylene groups, cycloalkylene groups, arylene groups and aryloxylene groups, wherein these groups are optionally employed individually or different groups are optionally employed in combination as X;
• (B) at least one non-linear multi-phenyl epoxy resin with an epoxy functionality of three or more selected from the group consisting of tris and higher (hydroxyphenyl) methane-based epoxy resins, tetra(hydroxyphenyl) ethane-based epoxy resins, fluorene-based epoxy resins, oligomers thereof, and combinations thereof in an amount of at least 10 PHR in total per 100 PHR of total epoxy resin;
• (C) at least one epoxy resin having an epoxy functionality of at least three which is neither a poly-naphthalene-based epoxy resin nor a non-linear multi-phenyl epoxy resin and which is a glycidyl ether of a diamine or a compound containing at least one amine group and at least one hydroxyl group per molecule;
• (D) at least one curing agent which comprises at least one diaminodiphenyl sulfone, wherein component (D) and components (A), (B), and (C) are present in amounts effective to provide a molar ratio of active hydrogens:epoxy groups ranging from 0.8:1 to 1.2:1;
• (E) at least one thermoplastic resin selected from the group consisting of polyethersulfones in an amount of from 5 to 30 PHR per 100 PHR of total epoxy resin;
• and
• (F) optionally, organic particles.