Abstract: An object of the present invention is to provide a stitched fiber-reinforced substrate material capable of suppressing the formation of microcracks in a fiber reinforced composite material. The stitched fiber-reinforced substrate material of the present invention is a stitched fiber-reinforced substrate material formed by stitching reinforcement fiber sheets made of reinforcement fibers using stitching yarns, to which an organic compound having a polar group is adhered. The organic compound having a polar group is preferably a compound having a polyoxyalkylene structure, and also preferably a compound having an epoxy group. The organic compound having a polar group is preferably adhered in an amount of 0.1 to 10 wt % with respect to the mass of the stitching yarn.

Abstract: An object of the present invention is to provide a stitched fiber-reinforced substrate material capable of suppressing the formation of microcracks in a fiber reinforced composite material. The stitched fiber-reinforced substrate material of the present invention is a fiber-reinforced substrate material formed by stitching reinforcement fiber sheets made of reinforcement fibers using stitching yarns, and the stitching yarn has a linear expansion coefficient in the fiber axial direction of ?1×10?6 to 70×10?6/K after being heated at 180° C. for 2 hours and then cooled. The stitching yarn is preferably a stitching yarn to which an organic compound having a polar group is adhered.

Abstract: An object of the present invention is to provide a stitched fiber-reinforced substrate material capable of suppressing the formation of microcracks in a fiber reinforced composite material. The stitched fiber-reinforced substrate material of the present invention is a stitched fiber-reinforced substrate material formed by stitching reinforcement fiber sheets made of reinforcement fibers using stitching yarns that exhibit an in-plane shear strength transition rate of 5% or more. The stitching yarn is preferably adhered by an organic compound having a polar group.

Abstract: The present invention provides an epoxy resin composition containing: an epoxy resin [A] that is a compound represented by Chemical formula (1) shown below: wherein R1 to R4 each independently represent one selected from the group consisting of a hydrogen atom, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and a halogen atom, and X represents one selected from —CH2—, —O—, —S—, —CO—, —C(?O)O—, —O—C(?O)—, —NHCO—, —CONH—, and —SO2—; a bifunctional epoxy resin [B] having an amine type glycidyl group; a curing agent [C] containing an aromatic polyamine, and having at least one substituent selected from an aliphatic substituent, an aromatic substituent, and a halogen atom at an ortho position with respect to an amino group; and a particulate rubber component [D].