Sheet molding compound and fiber-reinforced composite material

Abstract

A sheet molding compound which is a thickened material of an epoxy resin composition, including a component (A), a component (B), and a component (C), in which the component (A) is an epoxy resin staying at a liquid state at 25° C., the component (B) is an acid anhydride, the component (C) is an epoxy resin curing agent, and in the thickened material, at least some of epoxy groups of the component (A) and at least some of carboxy groups derived from the component (B) form ester.

1 . A sheet molding compound which is a thickened material of an epoxy resin composition, comprising:
 a component (A);   a component (B); and   a component (C),   wherein the component (A) is an epoxy resin staying in a liquid state at 25° C.,   the component (B) is an acid anhydride,   the component (C) is an epoxy resin curing agent, and   in the thickened material, at least some of epoxy groups of the component (A) and at least some of carboxy groups derived from the component (B) form ester.   
     
     
         2 . The sheet molding compound according to  claim 1 , further comprising:
 reinforcing fiber.   
     
     
         3 . The sheet molding compound according to  claim 1 ,
 wherein a viscosity of the epoxy resin composition that is measured by viscometry (a) at 30° C. 30 minutes after the preparation of the composition described below is 0.5 to 15 Pa·s,   viscometry (a): immediately after being prepared, the epoxy resin composition is put and sealed into an airtightable container and left to stand for 30 minutes at 23° C., and then a viscosity of the epoxy resin composition at 30° C. is measured.   
     
     
         4 . The sheet molding compound according to  claim 1 ,
 wherein a viscosity of the epoxy resin composition that is measured by viscometry (b) at 30° C. 10 days after the preparation of the composition described below is 2,000 to 55,000 Pa·s,   viscometry (b): immediately after being prepared, the epoxy resin composition is put and sealed into an airtightable container and left to stand for 10 days at 23° C., and then a viscosity of the epoxy resin composition at 30° C. is measured.   
     
     
         5 . The sheet molding compound according to  claim 1 ,
 wherein a viscosity of the epoxy resin composition that is measured by viscometry (c) at 30° C. 20 days after the preparation of the composition described below is 2,000 to 100,000 Pa·s,   viscometry (c): immediately after being prepared, the epoxy resin composition is put and sealed into an airtightable container and left to stand for 20 days at 23° C., and then a viscosity of the epoxy resin composition at 30° C. is measured.   
     
     
         6 . The sheet molding compound according to  claim 1 ,
 wherein a viscosity of the epoxy resin composition that is measured by viscometry (b) at 30° C. 10 days after the preparation of the composition by is 2,000 to 55,000 Pa·s,   the viscosity of the epoxy resin composition that is measured by viscometry (c) at 30° C. 20 days after the preparation of the composition described below is 2,000 to 100,000 Pa·s, and   a viscosity (b) measured by the viscometry (b) and a viscosity (c) measured by the viscometry (c) satisfy a relationship of [viscosity (c)]/[viscosity (b)]≤3,   viscometry (b): immediately after being prepared, the epoxy resin composition is put and sealed into an airtightable container and left to stand for 10 days at 23° C., and then a viscosity of the epoxy resin composition at 30° C. is measured,   viscometry (c): immediately after being prepared, the epoxy resin composition is put and sealed into an airtightable container and left to stand for 20 days at 23° C., and then a viscosity of the epoxy resin composition at 30° C. is measured.   
     
     
         7 . The sheet molding compound according to  claim 1 ,
 wherein a content of the component (B) is such that the amount of acid anhydride groups with respect to 1 equivalent of epoxy groups contained in the epoxy resin composition becomes 0.1 to 0.5 equivalents.   
     
     
         8 . The sheet molding compound according to  claim 1 ,
 wherein a content of the component (B) is 3 to 30 parts by mass with respect to 100 parts by mass of the entire epoxy resin contained in the epoxy resin composition.   
     
     
         9 . The sheet molding compound according to  claim 1 ,
 wherein a content of the component (C) is 0.1 to 25 parts by mass with respect to 100 parts by mass of the entire epoxy resin contained in the epoxy resin composition.   
     
     
         10 . The sheet molding compound according to  claim 1 ,
 wherein the component (A) contains a glycidyl amine-based epoxy resin.   
     
     
         11 . The sheet molding compound according to  claim 10 ,
 wherein a content of the glycidyl amine-based epoxy resin with respect to 100 parts by mass of the entire epoxy resin contained in the epoxy resin composition is 1 to 30 parts by mass.   
     
     
         12 . The sheet molding compound according to  claim 1 ,
 wherein the component (B) stays at a liquid state at 25° C.   
     
     
         13 . The sheet molding compound according to  claim 1 ,
 wherein the component (C) stays at a solid state at 25° C.   
     
     
         14 . The sheet molding compound according to  claim 1 ,
 wherein the component (B) contains a compound having two cyclic acid anhydrides in a molecule.   
     
     
         15 . The sheet molding compound according to  claim 1 ,
 wherein the component (B) contains a phthalic anhydride or a hydrogenated phthalic anhydride that may have a substituent.   
     
     
         16 . The sheet molding compound according to  claim 1 ,
 wherein the component (B) contains a hydrogenated phthalic anhydride that may have a substituent, and   the hydrogenated phthalic anhydride that may have a substituent is a compound represented by Formula (1) or a compound represented by Formula (2).   
       
         
           
           
               
               
           
         
       
     
     
         17 . The sheet molding compound according to  claim 1 ,
 wherein the component (C) contains an imidazole-based compound having a melting point of 120° C. to 300° C.   
     
     
         18 . The sheet molding compound according to  claim 1 ,
 wherein the epoxy resin composition further contains a component (D),   the component (1)) is dicyandiamide, and   a content of the component (D) with respect to 100 parts by mass of the entire epoxy resin contained in the epoxy resin composition is 0.1 to 5 parts by mass.   
     
     
         19 . The sheet molding compound according to  claim 1 ,
 wherein the component (C) further contains a component (E),   the component (E) is an imidazole-based compound staying in a liquid state at 25° C., and   a content of the component (E) with respect to 100 parts by mass of the entire epoxy resin contained in the epoxy resin composition is 0.01 to 0.2 parts by mass.   
     
     
         20 . A fiber-reinforced composite material which is a cured material of the sheet molding compound according to  claim 1 .