Curable composition and fiber reinforced composite material

Abstract

The present invention provides a curable composition comprising a urethane-modified epoxy resin (A) as an essential component of a main material, and an acid anhydride (B) as an essential component of a curing agent, wherein the urethane-modified epoxy resin (A) is a reaction product of a polyisocyanate compound (a1), a polyester polyol (a2), and a hydroxyl group-containing epoxy resin (a3) as essential reaction raw materials. The curable composition of the invention is advantageous in that a cured product having excellent fracture toughness and excellent tensile strength can be formed from the composition.

1 . A curable composition comprising a urethane-modified epoxy resin (A) as an essential component of a main material, and an acid anhydride (B) as an essential component of a curing agent, wherein the urethane-modified epoxy resin (A) is a reaction product of a polyisocyanate compound (a1), a polyester polyol (a2), and a hydroxyl group-containing epoxy resin (a3) as essential reaction raw materials. 
     
     
         2 . The curable composition according to  claim 1 , wherein the polyester polyol (a2) is a polyester diol having a number average molecular weight (Mn) of 500 to 4,000. 
     
     
         3 . The curable composition according to  claim 1 , wherein a linear aliphatic diol compound having 2 to 8 carbon atoms constitutes 80% by mass or more of a polyol raw material for the polyester polyol (a2). 
     
     
         4 . The curable composition according to  claim 1 , wherein the polyisocyanate compound (a1) has an isocyanate group content of 35% by mass or more. 
     
     
         5 . The curable composition according to  claim 1 , wherein the proportion of the mass of the urethane-modified epoxy resin (A) to the total mass of the epoxy resin component contained in the main material is in the range of 30 to 100% by mass. 
     
     
         6 . The curable composition according to  claim 1 , wherein the main material contains an aliphatic epoxy resin, in addition to the urethane-modified epoxy resin (A). 
     
     
         7 . The curable composition according to  claim 6 , wherein the mass ratio of the urethane-modified epoxy resin (A) and the aliphatic epoxy resin [urethane-modified epoxy resin (A)/aliphatic epoxy resin] is in the range of 30/70 to 100/0. 
     
     
         8 . A cured product of the curable composition according to  claim 1 . 
     
     
         9 . A fiber-reinforced composite material comprising the curable composition according to  claim 1  and a reinforcing fiber as essential components. 
     
     
         10 . A fiber-reinforced resin molded article comprising the cured product according to  claim 8  and a reinforcing fiber as essential components. 
     
     
         11 . A method for producing a fiber-reinforced resin molded article, the method comprising heat-curing the fiber-reinforced composite material according to  claim 9 . 
     
     
         12 . A cured product of the curable composition according to  claim 2 . 
     
     
         13 . A cured product of the curable composition according to  claim 3 . 
     
     
         14 . A cured product of the curable composition according to  claim 4 . 
     
     
         15 . A cured product of the curable composition according to  claim 5 . 
     
     
         16 . A cured product of the curable composition according to  claim 6 . 
     
     
         17 . A fiber-reinforced composite material comprising the curable composition according to  claim 2  and a reinforcing fiber as essential components. 
     
     
         18 . A fiber-reinforced composite material comprising the curable composition according to  claim 3  and a reinforcing fiber as essential components. 
     
     
         19 . A fiber-reinforced composite material comprising the curable composition according to  claim 4  and a reinforcing fiber as essential components. 
     
     
         20 . A fiber-reinforced composite material comprising the curable composition according to  claim 5  and a reinforcing fiber as essential components.