Fiber-reinforced resin prepreg, molded article, and fiber-reinforced thermoplastic resin prepreg

A fiber-reinforced thermoplastic resin prepreg, comprising:

• a matrix resin composition, and
• a carbon fiber base material including a carbon fiber bundle,
• wherein
• the matrix resin composition is impregnated in the carbon fiber base material,
• an average roughness Ra of a surface of single fibers constituting the carbon fiber bundle included in the carbon fiber base material is 1.0 to 4.0 nm,
• mass per unit length of the single fibers constituting the carbon fiber bundle included in the carbon fiber base material is 0.030 to 0.055 mg/m,
• an ipa value of the carbon fiber bundle measured by cyclic voltammetry is 0.14 to 0.20 μA/cm2, and
• the matrix resin composition is a thermoplastic resin composition having an impact absorption energy of 0.7 J or more measured using Impact Test specified below:
• Impact Test:
• a test piece of 100 mm in length and 100 mm in width is cut out of a film having a thickness of 100 μm formed using the matrix resin composition, the test piece is fixed with a clamp, a striking core with a ½ inch diameter is dropped at a falling speed of 3 m/sec on a center of the test piece at a temperature of 23° C. to apply an impact thereto, and impact absorption energy when the test piece is fractured is measured.

A method for producing a fiber-reinforced resin prepreg, the method comprising:

• impregnating a carbon fiber bundle with a matrix resin composition, wherein
• mass per unit length of single fibers constituting the carbon fiber bundle is 0.030 to 0.055 mg/m,
• an ipa value of the carbon fiber bundle measured by cyclic voltammetry is 0.14 μA/cm2 or more, and
• the matrix resin composition satisfies Condition 1 specified below:
• Condition 1:
• an impact strength of a film obtained by solidifying the matrix resin composition under Molding Conditions specified below is 12.0 KJ/m or more, and the impact strength is measured using Impact Test specified below:
• Molding Conditions:
• the matrix resin composition is extruded and drawn at a draw ratio of 1.1 times, and brought into contact for three seconds with a roll temperature-controlled to a temperature of (Tm −125° C.) in a case where a crystal melting enthalpy ΔHm of the matrix resin composition is 10 J/g or more, or to a temperature of (Tg −30° C.) in a case where the crystal melting enthalpy ΔHm of the matrix resin composition is less than 10 J/g, thereby obtaining a film having a thickness of 40 to 60 μm, where Tg and Tm are respectively a glass transition temperature and a melting point measured using differential scanning calorimetry in accordance with ISO11357,
• Impact Test:
• a test piece of 100 mm in length and 100 mm in width is cut out of the film, the test piece is fixed with a clamp, a striking core with a ½ inch diameter is dropped at a falling speed of 3 m/see on a center of the test piece at a temperature of 23° C. to apply an impact thereto, and impact absorption energy when the test piece is fractured is measured and divided by the film thickness to obtain the impact strength of the film.