Abstract: This invention relates to a flame retardant epoxy resin composition which includes an epoxy resin structure having an epoxy functionality of 2 or more with a measured total heat release value of not more than 23 kJ/g as well as an organic phosphinic acid structure (in reacted or unreacted form), as well as a prepreg, and a fiber reinforced composite material prepared using the epoxy resin composition. More specifically, an epoxy resin composition is provided that contains a combination of particular types of epoxy resins and curatives that provide sufficient flame retardance when cured at 163° C. for 15 minutes. The epoxy resin systems are also suitable for preparing a fiber-reinforced composite material that will also provide sufficient flame retardance for a variety of applications.

Abstract: This invention relates to a flame retardant fiber-reinforced composite material based on an epoxy resin composition which includes at least one epoxy resin having an epoxy functionality of at least 2 as well as at least one organic phosphinic acid or derivative thereof (e.g., an organic phosphinic acid-modified epoxy resin), reinforced with a fiber having a thermal conductivity?3 W/m·K at room temperature, as well as a prepreg for making such a flame retardant fiber-reinforced composite material. More specifically, a composite material is provided that contains a combination of particular types of epoxy resins, curatives, and reinforcing fibers that provide sufficient flame retardance for thin-ply laminates when cured at 163° C. for 15 minutes. These cured composites are also suitable for a variety of applications requiring flame retardancy.