| 摘要 |
PROBLEM TO BE SOLVED: To provide a molded body which comprises a fiber reinforced composite material, is light in weight, has shape flexibility and maintains isotropy.SOLUTION: A random mat comprises a reinforced fiber having 10-100 mm fiber length and 25-3,000 g/munit weight and a thermoplastic resin, wherein the ratio of mat occupied in a reinforced fiber bundle constituted of equal to or above critical single yarn number defined by the formula (1):(the critical single yarn number)=600/D is ≥30 vol.% and <90 vol.% and the average number (N) of fibers in the reinforced fiber bundle satisfies the formula (2):0.7×104/D2<N<6×104/D2, wherein D is average fiber diameter (μm). A prepreg 1 comprising the random mat is arranged in a mold comprising a cavity 2 and a cavity edge 3 in ≥50 and <90% charge rate defined by the formula (3):(the charge rate (%))=100×(base material surface area)/(mold cavity projected area), wherein both the base material surface area and the mold cavity projected area are projected areas in a draft direction. Then the prepreg is press-molded under a condition of a prescribed temperature and pressure and after that, the pressure is increased by 1.2-25 times and then the prepreg 1 is cooled to equal to or below a prescribed temperature, so that the prepreg 1 is molded. |
