Epoxy resin composition excellent in weather resistance and fiber-reinforced composite materials

Abstract

The present invention relates: to an epoxy resin composition comprising at least (A) an epoxy resin having a cycloalkane ring or cyclohexene ring but having neither aromatic ring nor aminic nitrogen atom, (B) a carboxylic anhydride having no aromatic ring, and (C) an ultraviolet absorbent, wherein a content of component (A) is from 70 to 100 percents by weight based on the total weight of epoxy resins, and a content of component (B) is from 70 to 100 percents by weight based on the total weight of carboxylic anhydrides. By this constitution, the present invention can provide an epoxy resin composition whose cured product excels in mechanical properties and weatherability, and a fiber reinforced composite material having excellent mechanical properties and weatherability.

1 . An epoxy resin composition comprising (A) an epoxy resin having a cycloalkane ring or a cyclohexene ring but having neither aromatic ring nor aminic nitrogen atom, (B) a carboxylic anhydride having no aromatic ring, and (C) an ultraviolet absorbent, wherein a content of component (A) is from 70 to 100 percents by weight based on the total weight of epoxy resins, and a content of component (B) is from 70 to 100 percents by weight based on the total weight of carboxylic anhydrides.  
     
     
         2 . An epoxy resin composition according to  claim 1 , which comprises not mare than 3 percents by weight, based on the weight of the epoxy resin composition, of an epoxy resin having an aromatic ring or an aminic nitrogen atom.  
     
     
         3 . An epoxy resin composition according to  claim 1 , wherein the component (A) has 1,2-epoxycyclohexane ring or 1,2-epoxycyclopentane ring.  
     
     
         4 . An epoxy resin composition according to  claim 1 , wherein the component (B) is a carboxylic anhydride having a cycloalkane ring or a cycloalkene ring.  
     
     
         5 . An epoxy resin composition according to  claim 1 , wherein the component (C) has a molecular extinction coefficient in 380 nm in chloroform of from 5.0×10 2  to 2.0×10 4 .  
     
     
         6 . An epoxy resin composition according to  claim 1 , wherein the component (C) is a benzotriazol ultraviolet absorbent.  
     
     
         7 . An epoxy resin composition according to  claim 1  which further comprises (D) an imidazole compound.  
     
     
         8 . An epoxy resin composition according to  claim 1  which further comprises (E) a polyol compound having neither aromatic ring nor aminic nitrogen atom.  
     
     
         9 . An epoxy resin cured product obtained by curing an epoxy resin composition of  claim 1 .  
     
     
         10 . A fiber reinforced composite material comprising reinforcing fibers and a thermosetting matrix resin, which has a color difference ΔE of not more than 4 in a 1500-hour weatherometer test by a sunshine carbon arc light without painting.  
     
     
         11 . A fiber reinforced composite material according to  claim 10 , wherein the thermosetting matrix resin is an epoxy resin cured product of  claim 9 .  
     
     
         12 . A fiber reinforced composite material according to  claim 10 , wherein the flexural modulus at room temperature of the thermosetting matrix resin is not less than 2.9 GPa.  
     
     
         13 . A fiber reinforced composite material according to  claim 10 , wherein glass transition temperature of the thermosetting matrix resin is not less than 90 degrees Celsius.  
     
     
         14 . A fiber reinforced composite material according to  claim 10 , wherein the reinforcing fibers are carbon fibers.  
     
     
         15 . A fiber reinforced composite material which further comprises a transparent resin layer on an outside surface of a fiber reinforced composite material of  claim 10 .  
     
     
         16 . A fiber reinforced composite material according to  claim 15 , which has a color difference ΔE*ab of not more than 4 in a 1500-hour weatherometer test by a sunshine carbon arc light.  
     
     
         17 . A fiber reinforced composite material according to  claim 15 , characterized by an average-of-roughness-height Ra in roughness measurement of a designed surface being from 0.05 to 2.0 micrometers.  
     
     
         18 . A fiber reinforced composite material according to  claim 15 , characterized by a maximum height Ry in roughness measurement of a designed surface being from 0.1 to 5.0 micrometers.  
     
     
         19 . A fiber reinforced composite material according to  claim 15 , characterized by an image clarity index NSIC of a designed surface being from 30 to 80 percents.  
     
     
         20 . A fiber reinforced composite material, according to  claim 15 , characterized by a pencil hardness of a designed surface being for above.  
     
     
         21 . A vehicle member comprising a fiber reinforced composite material of  claim 15 .  
     
     
         22 . A sporting goods member comprising a fiber reinforced composite material of  claim 10 .  
     
     
         23 . A process for preparing a fiber reinforced composite material which comprises the steps of impregnating an epoxy resin composition of  claim 1  into reinforcing fibers, and heating to cure the epoxy resin composition impregnated into the reinforcing fibers, characterized by impregnating the epoxy resin compositions of  claim 1  under the conditions that viscosity thereof is from 10 to 1000 mPa.s.  
     
     
         24 . A process for preparing a fiber reinforced composite material which comprises the steps of impregnating an epoxy resin composition of  claim 1  into reinforcing fibers to obtain prepregs, thereafter laminating the prepregs to give a shape, and heating to cure the epoxy resin composition.