An epoxy resin composition including components (A), (B), (C) and (D); wherein a content of the component (A) is 60 to 90 parts by mass, and a content of the component (B) is 10 to 40 parts by mass, with respect to epoxy resins; the epoxy resin composition has a characteristic that, when cured and formed into a cured product, the cured product has a glass transition temperature of 200° C. or higher; and a viscosity at 100° C. of the resin composition is 5 to 35 Pa.Math.s, wherein Component (A) is an aromatic epoxy resin having at least 3 glycidyl groups in one molecule, Component (B) is an aromatic epoxy resin having two glycidyl groups in one molecule, Component (C) is an aromatic polysulfone resin having a reduced viscosity of 0.18 to 0.30 dl/g; and Component (D) is an aromatic amine compound.

The objective of the present invention is to provide a polyarylketone resin composition, a fiber-reinforced resin base material, and formed products therefrom having excellent thermal stability and mechanical properties. In order to achieve the above objective, the present invention has the following constitution. That is, the polyaryletherketone resin composition comprises (A) a polyaryletherketone and (B) a transition metal compound, wherein the transition metal content is between 0.001 parts by mass and 4 parts by mass inclusive with respect to 100 parts by mass of (A) the polyaryletherketone.

A prepreg includes [A], [B], and [C] described below. The [B] further comprises [B′]; a ratio of a mole number of an active hydrogen contained in [B′] to a mole number of an epoxy group in an epoxy resin contained in [B] is in a range of 0.6 to 1.1 both inclusive; [C] is present on a surface of the prepreg; and [A] that crosses over a boundary surface between a resin region containing [B] and a resin region containing [C] and that is in contact with both resin regions is present: [A] a reinforcing fiber; [B] an epoxy resin composition; an amine compound; and [C] a thermoplastic resin composition.

A sheet molding compound resin composition containing a thermosetting resin (A), a resin-curing agent (B), and a glycidyl ether (C) including an alkyl group having a carbon atom number of 7 to 14 and a glycidyl group is provided. The sheet molding compound resin composition can be favorably used for a sheet molding compound and a molded article of the sheet molding compound as a result of having excellent impregnating ability with respect to carbon fiber regardless of the resin viscosity.

An object of the present invention is to provide an epoxy resin composition that can be preferably used for prepreg and fiber reinforced composite material applications, has high Tg, and is excellent in elastic modulus and strength. The present invention is the epoxy resin composition including the following components [A] to [C] and satisfying the following conditions (1) to (2): [A]: epoxy resin [B]: polyamine curing agent, and [C]: a compound having a boiling point of 130° C. or more and a molecular weight m of 50 or more and 250 or less, the compound having no epoxy group in the molecule and having substantially no curing ability of an epoxy resin, (1): at least a part of the component [C] satisfies that the sum of the polar component and the hydrogen bond component in the Hansen solubility parameters is 10.0 or less, (2): the ratio C/E of the amount by mole, E, for epoxy groups of the component [A] to the amount by mole, C, of the component [C] satisfying the condition (1) is 0.01 or more and 0.20 or less.

Provided is a sheet molding compound having excellent thick portion-molding properties that can inhibit the occurrence of internal cracks even during the molding of a thick portion and enables a carbon fiber composite material molded article to be excellently released from a die. Also provided is a carbon fiber composite material molded article. The sheet molding compound of the present invention contains a fiber substrate (A) containing carbon fiber and a thermosetting resin composition (B), in which an average fiber length of the carbon fiber is 5 mm or more, and a volumetric molding shrinkage rate of the thermosetting resin composition (B) is 0.5% or more and 4.4% or less. Furthermore, the carbon fiber composite material molded article of the present invention has a thick portion having a thickness of 10 mm or more, in which the thick portion is formed of a cured material of the sheet molding compound of the present invention.

The purpose of the present invention is to provide: an epoxy resin composition which enables the achievement of a resin cured product that has high flame retardancy and excellent mechanical characteristics; and a prepreg and a fiber-reinforced composite material, each of which uses this epoxy resin composition. One embodiment of the epoxy resin composition according to the present invention, said epoxy resin composition having achieved the above-described purpose, contains the components (A) and (B) described below. (A): a bifunctional glycidyl amine type epoxy compound (B): an epoxy compound having a specific structure and/or an epoxy compound having another specific structure

Covalent network polymers that include one or more of a cure rate modifying (CRM) additive, a tack modifying additive, a flame retardant additive, a physical additive, and a viscosity modifying additive allow the viscosity, pot life, tackiness and safety of chemical mixtures and products to be tailored without sacrificing the mechanical properties or reprocessability of the final vitrimers. Use of additives also enables previously infeasible manufacturing techniques.

Methods of repairing damaged composites are described. The damaged composites can comprise a polymeric matrix and one or more layers of fibers (e.g., carbon or glass fibers). According to the described method, the damaged area of the composite is replaced by an insert comprising a core geometry and radial projections. The insert can comprise the same polymeric matrix and one or more layers of fibers as the original composite of the damaged composite. The method can provide a repaired composite with greater compressive strength and/or greater tensile strength than a composite repaired with a traditional patch having no radial projections.

A prepreg having at least one layer of fibres and a curable thermosetting resin system at least partly impregnating the at least one layer of fibres, wherein the curable thermosetting resin system includes a curable thermosetting resin including at least two epoxide groups, a curing agent that includes at least one amine group, and an accelerator that includes an azole group; wherein the curable thermosetting resin, the curing agent and the accelerator are provided in respective concentrations in the prepreg to provide that, after curing the thermosetting resin at a cure temperature of at least 140° C. for a period of from 1 to 6 minutes, (i) the cured thermosetting resin has a glass transition temperature Tg which is greater than the cure temperature and is within the range of from 150° C. to 180° C. and (ii) the cured thermosetting resin is at least 90% cured.