Method for producing fiber-reinforced plastic

A method for producing a rigid fiber-reinforced plastic having a three-dimensional shape using a tape-shaped substrate A and a sheet substrate C,

• the tape-shaped substrate A comprising one or more sheets of incised prepreg a,
• the incised prepreg a being a prepreg including unidirectionally oriented reinforcing fibers and a resin and having a plurality of incisions dividing the reinforcing fibers formed in the prepreg, and satisfying the following condition 1,
• the sheet substrate C being a substrate comprising one or more sheets of incised prepreg c,
• the incised prepreg c being a prepreg including unidirectionally oriented reinforcing fibers and a resin and having a plurality of incisions dividing the reinforcing fibers formed in the prepreg, and satisfying the following condition 2, wherein
• the method for producing a fiber-reinforced plastic comprises:
• a placement step (A) of placing a plurality of tape-shaped substrates A on a mold such that each of the tape-shaped substrates A forms an overlapping portion in which the tape-shaped substrate A overlaps one or more other tape-shaped substrates A and a non-overlapping portion in which the tape-shaped substrate A does not overlap any other tape-shaped substrates A;
• a placement step (C) of placing a sheet substrate C;
• and
• a molding step of heating and pressing the tape-shaped substrates A and the sheet substrate C placed,
• (Condition 1)
• the average length xa (mm) of the incisions and the average length ya (mm) of the reinforcing fibers divided by the incisions satisfy ya>6.0xa+10,
• (Condition 2)
• the average length xc (mm) of the incisions and the average length yc (mm) of the reinforcing fibers divided by the incisions satisfy yc≤6.0xc+10;
• wherein in the placement step (A), the ratio of the total of the area of the overlapping portion to the total of the area of the non-overlapping portion is 0.05 to 0.8;
• thereby producing the rigid fiber-reinforced plastic having a three-dimensional shape.