Method for producing fiber-reinforced composite material

A method for producing a fiber-reinforced composite material comprising a polyimide resin (A) and a continuous reinforcing fiber (B), wherein

• the polyimide resin (A) comprises a repeating structural unit represented by the following formula (1) and a repeating structural unit represented by the following formula (2), and
• a content ratio of the repeating structural unit of the formula (1) with respect to the total of the repeating structural unit of the formula (1) and the repeating structural unit of the formula (2) is 20 to 70 mol %:
• wherein R1 represents a divalent group having from 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure;
• R2 represents a divalent chain aliphatic group having from 5 to 16 carbon atoms;
• and X1 and X2 each independently represent a tetravalent group having from 6 to 22 carbon atoms containing at least one aromatic ring,
• the method comprising the following steps (I) and (II) in this order:
• step (I):
• a step of laminating at least one polyimide resin (A) layer and at least one continuous reinforcing fiber (B) layer to obtain a laminated product;
• and
• step (II):
• a step of molding the laminated product by heating and pressurizing under a condition where a working parameter X expressed by the following expression (i) is 35 or more and 87 or less:
• X=(Tp−Tm)3×P1/2/1000 (i)
• wherein in the expression (i), Tp represents a temperature (° C.) during the molding, Tm represents a melting point (° C.) of the polyimide resin (A), and P represents a press pressure (MPa) during the molding.