Epoxy resin compositions for fiber-reinforced composite materials, process for production of the materials and fiber-reinforced composite materials

摘要

The present invention relates to an epoxy resin composition for fiber reinforced composite material comprising the following components (1) - (3) as essential components, their mixing ratios meeting the following conditions (I) - (IV), and component (3) being dissolved homogeneously: component (1): epoxy resin that is liquid at room temperature, component (2): aromatic polyamine that is liquid at room temperature, component (3): diaminodiphenylsulfone, condition (I): The proportion of component (1) relative to the entire epoxy resin in the composition is 60-100 wt%, condition (II): The sum of the proportions of components (2) and (3) relative to the entire polyamine in the composition is 70-100 wt%, condition (III): The proportion of component (3) relative to the entire polyamine in the composition is 25-60 wt%, and condition (IV): The stoichiometric ratio of the entire polyamine to the entire epoxy resin in the composition is 0.7-1.3. Another embodiment of the invention relates to an epoxy resin composition for fiber reinforced composite material that contains at least the following components (4) - (6), forms a cured product with a theoretical molecular weight between crosslinking points in the range of 250-350 g/mol, and has an initial viscosity at 80 DEG C of 1-500 MPa.s: (4): aromatic epoxy resin with tri- or higher functionality, (5): aromatic epoxy resin with di- or higher and lower than tri-functionality, and (6): aromatic polyamine, the molecular weight between crosslinking points being defined as the weight of the entire cured epoxy resin divided by the number of crosslinking points contained in the entire cured epoxy resin. The invention also relates to an epoxy resin composition for fiber reinforced composite material that consists of the following components (7) and (8): (7) a polyglycidyl ether of phenol aralkyl resin as represented by the following formula: where R<1>, R<2>, R<3> and R<4> denote a hydrogen atom, an alkyl group having 1-8 carbon atoms, or a halogen atom, and m and n denote an integer of 1-4 and a real number of 0 or more and less than 1, respectively, and (8) polyamine. With the constitution described above, the present invention can provide a liquid epoxy resin composition for low cost production of high performance fiber reinforced composite material, that has a low viscosity at relatively low temperatures, and that after being cured, the cured product is high in glass transition temperature, elastic modulus and toughness while being small in the glass temperature decrease caused by water absorption and also small in the coefficient of linear expansion; and can provide a method to produce fiber reinforced composite material therefrom. Fiber reinforced composite material produced according to the present invention can serve as material for parts of aircraft, including main wing, tail, rotor blade, fairing, cowl, and door; parts of spacecraft, including motor case and main wing; and parts of space satellite body structure. They can also be used preferably as material for automobile chassis and railroad vehicle body structure.