In the press and injection hybrid molding of CFRTP, short or long fiber-reinforced thermoplastics are injected on the continuous fiber-reinforced thermoplastics, which are used for the outer shell material. Since its fracture often occurs at a rib root portion, which is the interface of the injected materials and the continuous fiber-reinforced thermoplastics, the rib root portion has to be strengthened. By using slit material having high formability for the outer shell material, the penetration height of the outer shell material into the rib becomes higher, therefore, improvement of the strength of rib root portion can be expected. In this study, to clarify the effect of penetration height of slit materials on the mechanical properties of the rib root portion of the press and injection hybrid molding, slit materials were used for the outer shell material, and tensile tests of the surface layer and bonding strength at rib root were conducted. Experimental results reveal that the press and injection hybrid molding using slit materials in half of the continuous fiber-reinforced thermoplastics prepreg possesses the good combination of high bonding strength of rib root portion and high tensile strength of the surface layer.
