Epoxy resin composition with epoxy groups and active hydrogens having different molar equivalents

An epoxy resin composition with epoxy groups and active hydrogens having different molar equivalents, comprising an epoxy resin component and a curing agent component, wherein a mixing ratio of the epoxy resin component and the curing agent component is not a theoretical value calculated based on an epoxy equivalent and an active hydrogen equivalent, and the mixing ratio of the epoxy resin component and the curing agent component is a mixing ratio of a cured product with a maximum glass transition temperature Tg among cured products with different mixing ratios measured experimentally;

• according to a weight percentage in a total weight of the epoxy resin component, the epoxy resin component comprises:
• 50 wt % to 100 wt % of a bisphenol A epoxy resin;
• and
• according to a weight percentage in a total weight of the curing agent component, the curing agent component comprises:
• 60 wt % to 98 wt % of polyetheramine (PEA) and
• 2 wt % to 20 wt % of a Mannich base having a viscosity of less than 400 mPa·s at 25° C.;
• wherein a molar ratio of epoxy groups to active hydrogens in the mixture of the epoxy resin component and the curing agent component at said mixing ratio of a cured product with a maximum glass transition temperature Tg is 1.7.