Fiber-reinforced plastic and production method therefor

Abstract

The purpose of the present invention is to obtain a fiber-reinforced plastic that is capable of controlling anisotropy, has excellent mechanical characteristics, has little variation, has excellent heat resistance, and has good fluidity during forming. A production method for fiber-reinforced plastic, having: a step in which a material (A) ( 100 ) including a prepreg base material is obtained, said prepreg base material having cuts therein and having a thermoplastic resin impregnated in reinforcing fibers ( 110 ) arranged in parallel in one direction; a step in which a pressurizing device is used that applies a substantially uniform pressure in a direction (X) orthogonal to the travel direction of the material (A) ( 100 ) and the material (A) ( 100 ) is caused to travel in the one direction and is pressurized while being heated to a prescribed temperature (T), an angle (.theta.) of −20-20.degree. being formed between the orthogonal direction (X) and a fiber axial direction (Y) for the reinforcing fibers ( 110 ) of the prepreg base material; and a step in which the material (A) ( 100 ) pressurized by the pressurizing device is cooled and the fiber-reinforced plastic is obtained

1 : A method for producing a fiber-reinforced plastic, the method comprising:
 (i) pressing a material (A) with a pressing apparatus that applies pressure approximately uniformly in a direction orthogonal to a travel direction of the material (A); and   (ii) cooling the material (A) that has been pressed by the pressing apparatus, and thereby obtaining a fiber-reinforced plastic,   wherein:   the material (A) comprises a prepreg substrate in which reinforcing fibers that are unidirectionally arranged in parallel are impregnated with a matrix resin, and slits are formed so as to intersect the fiber axes; and   the pressing (i) occurs such that the material (A) travels in one direction, with the angles θ formed by fiber axial directions of the reinforcing fibers of the prepreg substrate with respect to an orthogonal direction being adjusted to −20° to 20°, in a state in which the material (A) is heated to a temperature T that is higher than or equal to a melting point of the matrix resin, or is higher than or equal to a glass transition temperature if the matrix resin does not have a melting point.   
     
     
         2 : The method for producing a fiber-reinforced plastic according to  claim 1 , wherein the pressing (i) comprises (i-1) pressing the material (A) in a state of being heated to the temperature T, while causing the material (A) to travel in one direction, with a pressing apparatus which includes at least a pair of press rolls, with the shaft line direction of the rolls coinciding with the orthogonal direction. 
     
     
         3 : The method for producing a fiber-reinforced plastic according to  claim 2 , wherein the press rolls are heated rolls. 
     
     
         4 : The method for producing a fiber-reinforced plastic according to  claim 1 , wherein the angle θ is adjusted to −5° to 5°. 
     
     
         5 : The method for producing a fiber-reinforced plastic according to  claim 1 , wherein a thickness of the material (A) is 0.25 mm to 6.0 mm. 
     
     
         6 : The method for producing a fiber-reinforced plastic according to  claim 1 , wherein the matrix resin is a thermoplastic resin. 
     
     
         7 : The method for producing a fiber-reinforced plastic according to  claim 1 , wherein the matrix resin comprises at least one selected from the group consisting of a polyolefin resin, a modified polypropylene resin, a polyamide resin, and a polycarbonate resin. 
     
     
         8 : The method for producing a fiber-reinforced plastic according to  claim 1 , wherein a length L of the reinforcing fibers cut by slits in the prepreg substrate is 1 mm to 100 mm. 
     
     
         9 : The method for producing a fiber-reinforced plastic according to  claim 2 , wherein the pressing (i-1) occurs such that a double belt-type heat press machine by which the material (A) is interposed between at least one pair of belts and is heated while the material (A) is caused to travel so as to pass through between at least one pair of press rolls, and the material (A) is pressed with the at least one pair of press rolls. 
     
     
         10 : A fiber-reinforced plastic, comprising carbon fibers and a matrix resin,
 wherein:   a fiber length of the carbon fibers is 1 mm to 100 mm;   a degree of orientation pf of the carbon fibers in a direction that orthogonally intersects a thickness direction is 0.001 to 0.8; and   an eccentricity coefficient ec of an orientation profile of the carbon fibers in a plane that orthogonally intersects the thickness direction is 1×10 −5  to 9×10 −5 .   
     
     
         11 : The fiber-reinforced plastic according to  claim 10 , wherein a dispersion parameter dp of the carbon fibers in a cross-section in the thickness direction is 100 to 80. 
     
     
         12 : The fiber-reinforced plastic according to  claim 10 , wherein the matrix resin is formed from a thermoplastic resin. 
     
     
         13 : The fiber-reinforced plastic according to  claim 10 , wherein a fiber volume percentage content of the carbon fibers is 5% to 70% by volume. 
     
     
         14 : The fiber-reinforced plastic according to  claim 10 , wherein the fiber length of the carbon fibers is 10 mm to 50 mm.