Prepreg, Fiber-Reinforced Composite Resin Molded Article, Method for Producing Tubular Molded Article, Epoxy Resin Composition, and Tubular Molded Article

A method for producing a tubular molded article, comprising:

• placing a tubular prepreg including a resin composition and a reinforcing fiber in a mold;
• heating the tubular prepreg at 130° C. or higher;
• and
• pressing the tubular prepreg against the mold by expanding a medium from an inside of the tubular prepreg, thereby molding a tubular molded article,
• wherein the resin composition includes an oxazolidone epoxy resin, a novolac epoxy resin, and a curing agent.

An epoxy resin composition comprising:

• an epoxy resin;
• and
• a curing agent,
• wherein a glass transition point of the epoxy resin composition is 140° C. or higher in a case where the epoxy resin composition is heated at 130° C. to 150° C. to obtain a cured resin plate, a curing completion time in the following measuring method is 12 minutes or less:
• according to JIS K 6300, in which a change in torque value (N·m) at a die temperature of 140° C. is measured to obtain a torque-time curve;
• and a time until an inclination of a tangent line of the obtained torque-time curve becomes 1/30 of a maximum value after the inclination reaches the maximum is defined as the curing completion time, and
• the cured resin plate has a bending strength of 174 MPa or more, a flexural modulus of 3.6 GPa or more, and a breaking strain of 9% or more.