Method for manufacturing fiber-reinforced composite material and fiber-reinforced composite material

Abstract

The purpose of the present invention is to obtain a fiber-reinforced composite material having excellent appearance or mechanical characteristics, whereby a three-dimensional shape is molded with high productivity while appearance defects such as fiber meandering or wrinkling are suppressed. In this method for manufacturing a fiber-reinforced composite material, when a stack in which a plurality of sheet-shaped prepregs (X) in which a plurality of continuously arranged reinforcing fibers are impregnated with a matrix resin composition are layered in different fiber directions is molded into a three-dimensional shape by a molding die ( 100 ) provided with a lower die ( 110 ) and an upper die ( 112 ), a stretchable sheet ( 10 ) or a resin film (Y) used in the stack ( 12 ) is utilized. In this method for manufacturing a fiber-reinforced composite material, the stack may be pre-molded to obtain a preform, and the preform may be furthermore compression-molded to obtain a fiber-reinforced composite material.

1 . A method for manufacturing a three-dimensional shaped molded article made of a fiber-reinforced composite material, the method comprising:
 preparing a stack comprising (i) a plurality of sheet-shaped prepregs which are each either a UD prepreg or a cloth prepreg and (ii) a resin material which is either a heat-curable resin film consisting of a resin composition or a sheet molding compound comprising a resin composition and short fibers dispersed therein, laminated with one another, and   obtaining the molded article by compression molding in which the stack is cured by being heated and pressurized in a molding die;   wherein a plurality of the sheet-shaped prepregs comprise two of the sheet-shaped prepregs having different fiber directions, and   wherein a plurality of the sheet-shaped prepregs comprise two of the sheet-shaped prepregs arranged adjacently to each other with the resin material sandwiched therebetween.   
     
     
         2 . The method according to  claim 1 , wherein the stack is formed into a preform by preparatory molding and the preform is further subjected to the compression molding. 
     
     
         3 . (canceled) 
     
     
         4 . The method according to  claim 1 , wherein the stack comprises a unit having a five-layer configuration of sheet-shaped prepreg (A)/sheet-shaped prepreg (B)/the resin material (C)/sheet-shaped prepreg (D)/sheet-shaped prepreg (E),
 the sheet-shaped prepreg (A), the sheet-shaped prepreg (B), the sheet-shaped prepreg (D) and the sheet-shaped prepreg (E) are each either a UD prepreg or a cloth prepreg, fiber directions of the sheet-shaped prepregs (B), (D) and (E) are each from 15° to 165° when a fiber direction of the sheet-shaped prepreg (A) is taken as 0°, and   fiber directions of the sheet-shaped prepregs (A), (B), (D) and (E) are different from one another.   
     
     
         5 . The method according to  claim 4 , wherein a fiber direction of the sheet-shaped prepreg (B) is from 85° to 95°, a fiber direction of the sheet-shaped prepreg (D) is from 30° to 60°, and a fiber direction of the sheet-shaped prepreg (E) is from 120° to 150°. 
     
     
         6 . The method according to  claim 4 , wherein the stack comprises two of the units laminated adjacently to each other sandwiching therebetween a resin material which is either a heat-curable resin film consisting of a resin composition or a sheet molding compound comprising a resin composition and short fibers dispersed therein. 
     
     
         7 . The method according to  claim 6 , wherein the stack comprises two of the units laminated adjacently to each other directly or sandwiching therebetween a resin material which is either a heat-curable resin film consisting of a resin composition or a sheet molding compound comprising a resin composition and short fibers dispersed therein, such that fiber directions are mirror symmetric between the two of the units with respect to a symmetric plane existing between the two of the units. 
     
     
         8 . The method according to  claim 5 , wherein a difference in angle between the fiber direction of the sheet-shaped prepreg (D) and the fiber direction of the sheet-shaped prepreg (E) is 90°. 
     
     
         9 . The method according to  claim 1 , wherein the three-dimensional shaped molded article has a three-dimensional shape which cannot be developed in a plane. 
     
     
         10 - 11 . (canceled) 
     
     
         12 . The method according to  claim 1 , wherein a plurality of the sheet-shaped prepreg comprise a cloth prepreg. 
     
     
         13 - 21 . (canceled) 
     
     
         22 . The method according to  claim 1 , wherein the resin material is the heat-curable resin film. 
     
     
         23 . The method according to  claim 1 , wherein the resin material is the sheet molding compound. 
     
     
         24 . The method according to  claim 22 , wherein a matrix resin in the sheet shaped prepregs and the resin composition in the heat-curable resin film have the same composition. 
     
     
         25 . The method according to  claim 22 , wherein a thickness of the heat-curable resin film is from 0.1 to 1 mm.