Epoxy resin compositions for fiber-reinforced composite materials, process for production of the materials and fiber-reinforced composite materials

Abstract

The present invention relates to an epoxy resin composition for fiber reinforced composite material comprising the following components (1)-(3) as essential components, their mixing ratios meeting the following conditions (I)-(IV), and component (3) being dissolved homogeneously: component (1): epoxy resin that is liquid at room temperature, component (2): aromatic polyamine that is liquid at room temperature, component (3): diaminodiphenylsulfone, condition (I): The proportion of component (1) relative to the entire epoxy resin in the composition is 60-100 wt %, condition (II): The sum of the proportions of components (2) and (3) relative to the entire polyamine in the composition is 70-100 wt %, condition (III): The proportion of component (3) relative to the entire polyamine in the composition is 25-60 wt %, and condition (IV): The stoichiometric ratio of the entire polyamine to the entire epoxy resin in the composition is 0.7-1.3. Another embodiment of the invention relates to an epoxy resin composition for fiber reinforced composite material that contains at least the following components (4)-(6), forms a cured product with a theoretical molecular weight between crosslinking points in the range of 250-350 g/mol, and has an initial viscosity at 80° C. of 1-500 MPa·s: (4): aromatic epoxy resin with tri- or higher functionality, (5): aromatic epoxy resin with di- or higher and lower than tri-functionality, and (6): aromatic polyamine, the molecular weight between crosslinking points being defined as the weight of the entire cured epoxy resin divided by the number of crosslinking points contained in the entire cured epoxy resin. The invention also relates to an epoxy resin composition for fiber reinforced composite material that consists of the following components (7) and (8): (7) a polyglycidyl ether of phenol aralkyl resin as represented by the following formula: where R 1 , R 2 , R 3 and R 4 denote a hydrogen atom, an alkyl group having 1-8 carbon atoms, or a halogen atom, and m and n denote an integer of 1-4 and a real number of 0 or more and less than 1, respectively, and (8) polyamine. With the constitution described above, the present invention can provide a liquid epoxy resin composition for low cost production of high performance fiber reinforced composite material, that has a low viscosity at relatively low temperatures, and that after being cured, the cured product is high in glass transition temperature, elastic modulus and toughness while being small in the glass temperature decrease caused by water absorption and also small in the coefficient of linear expansion; and can provide a method to produce fiber reinforced composite material therefrom. Fiber reinforced composite material produced according to the present invention can serve as material for parts of aircraft, including main wing, tail, rotor blade, fairing, cowl, and door; parts of spacecraft, including motor case and main wing; and parts of space satellite body structure. They can also be used preferably as material for automobile chassis and railroad vehicle body structure.

1 . An epoxy resin composition for fiber reinforced composite material comprising the following components (1)-(3) as essential components and meeting the following conditions (I)-(IV) for mixing rations, wherein component (3) is dissolved homogeneously: 
 Component (1): epoxy resin that is liquid at room temperature,    Component (2): aromatic polyamine that is liquid at room temperature,    Component (3): diaminodiphenylsulfone,    Condition (I): The proportion of component (1) relative to the entire epoxy resin in the composition is 60-100 wt %,    Condition (II): The total proportion of component (2) and component (3) combined relative to the entire polyamine in the composition is 70-100 wt %,    Condition (III): The proportion of component (3) relative to the entire polyamine in the composition is 25-60 wt %, and    Condition (IV): The stoichiometric ratio of the entire polyamine to the entire epoxy resin in the composition is 0.7-1.3.    
     
     
         2 . An epoxy resin composition for fiber reinforced composite material according to  claim 1  that is produced by mixing the following two liquids: 
 Liquid (A1): a liquid comprising component (1), and  
 Liquid (B1): a liquid comprising components (2) and (3), wherein component (3) is dissolved homogeneously.  
 
     
     
         3 . An epoxy resin composition for fiber reinforced composite material according to  claim 2  wherein precipitation of component (3) does not take place in liquid (B1) during storage for 30 days at 5° C.  
     
     
         4 . An epoxy resin composition for fiber reinforced composite material according to  claim 1  wherein the weight ratio of component (3) to component (2) is 0.25 or more.  
     
     
         5 . An epoxy resin composition for fiber reinforced composite material according to  claim 1  wherein component (2) comprises diethyl toluenediamine.  
     
     
         6 . An epoxy resin composition for fiber reinforced composite material according to  claim 1  wherein component (3) comprises 3,3′-diaminodiphenylsulfone.  
     
     
         7 . An epoxy resin composition for fiber reinforced composite material according to  claim 1  wherein component (3) comprises 3,3′-diaminodiphenylsulfone and 4,4′-diaminodiphenylsulfone  
     
     
         8 . An epoxy resin composition for fiber reinforced composite material according to  claim 1 , wherein the cured product of the epoxy resin composition obtained by being cured for two hours at 180° C., has a glass transition temperature of 170° C. or more and a coefficient of linear expansion of 7×10 −5 K −1  or less over the temperature range from 30° C. to 160° C.  
     
     
         9 . An epoxy resin composition for fiber reinforced composite material according to  claim 1  wherein the initial viscosity at 80° C. is in the range of 1-500 MPa·s.  
     
     
         10 . An epoxy resin composition for fiber reinforced composite material according to  claim 1  wherein the viscosity after storage for one hour at 80° C. is four times the initial viscosity or less  
     
     
         11 . An epoxy resin composition for fiber reinforced composite material according to  claim 1  wherein the viscosity after storage for one hour at 80° C. is in the range of 1-1000 MPa·s  
     
     
         12 . An epoxy resin composition for fiber reinforced composite material according to  claim 1 , wherein the cured product of the epoxy resin composition obtained by being cured for two hours at 130° C., has a glass transition temperature of 120° C. or more.  
     
     
         13 . An epoxy resin composition for fiber reinforced composite material according to  claim 1  that contains an accelerator selected from strong acid esters, onium salts, Lewis acid-amine complexes, and polyphenols.  
     
     
         14 . An epoxy resin composition for fiber reinforced composite material that contains at least the following components (4)-(6) wherein a theoretical molecular weight between crosslinking points of the cured product of the epoxy resin composition is 250-350 g/mol and an initial viscosity at 80° C. is 1-500 MPa·s: 
 (4): aromatic epoxy resin having tri- or higher functionality,  
 (5): aromatic epoxy resin of di- or higher and less than tri-functionality, and  
 (6): aromatic polyamine,  
 said theoretical molecular weight between crosslinking points being defined as the weight of the entire cured epoxy resin divided by the number of crosslinking points contained in the entire cured epoxy resin.  
 
     
     
         15 . An epoxy resin composition for fiber reinforced composite material according to  claim 14  that is produced by mixing the following two liquids: 
 liquid (A2): liquid comprising components (4) and (5),  
 liquid (B2): liquid comprising component (6).  
 
     
     
         16 . An epoxy resin composition for fiber reinforced composite material according to  claim 14  wherein component (4) accounts for 20-50 wt % of the entire epoxy resin.  
     
     
         17 . An epoxy resin composition for fiber reinforced composite material according to  claim 14  wherein component (4) is at least one selected from the group consisting of N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane, N,N,O-triglycidyl-m-aminophenol, N,O-triglycidyl-p-aminophenol, alkyl-substituted derivatives of any of the foregoing and N,N,N′,N′-tetraglycidyl-m-xylene diamine.  
     
     
         18 . An epoxy resin composition for fiber reinforced composite material according to  claim 14  wherein component (5) is at least. one selected from the group consisting of polyglycidyl ethers in the form of a condensation product of dicycolpentadiene and phenol or a substituent derivative of the phenol; diglycidyl ether of dihydroxynaphthalene; diglycidyl ether of dihydroxybiphenyl or its substituent derivative; diglycidyl ether of 9,9-bis(4-hydroxyphenyl)fluorine, and polyglycidyl ether of phenol aralkyl resin.  
     
     
         19 . An epoxy resin composition for fiber reinforced composite material according to  claim 14  wherein component (6) contains at least diethyl toluenediamine.  
     
     
         20 . An epoxy resin composition for fiber reinforced composite material according to  claim 14  wherein component (6) contains at least diaminodiphenylsulfone.  
     
     
         21 . An epoxy resin composition for fiber reinforced composite material according to  claim 14 , wherein, the cured product of the epoxy resin composition obtained by being cured for two hours at 180° C., has a flexural modulus at 25° C. in the range of 3.3-4.5 GPa.  
     
     
         22 . An epoxy resin composition for fiber reinforced composite material according to  claim 14 , wherein the cured product of the epoxy resin composition obtained by being cured for two hours at 180° C., has a glass transition temperature of 170° C. or more.  
     
     
         23 . An epoxy resin composition for fiber reinforced composite material according to  claim 14  that wherein the cured product of the epoxy resin composition obtained by being cured for two hours at 180° C., has a tensile elongation of 4% or more.  
     
     
         24 . An epoxy resin composition for fiber reinforced composite material according to  claim 14  that, after being left to stand for one hour at 80° C. , has a viscosity that is four times the initial viscosity or less.  
     
     
         25 . An epoxy resin composition for fiber reinforced composite material according to  claim 14 , wherein the cured product of the epoxy resin composition obtained by being cured for two hours at 130° C. , has a glass transition temperature of 120° C. or more.  
     
     
         26 . An epoxy resin composition for fiber reinforced composite material that contains at least the following components (7) and (8): 
 (7) a polyglycidyl ether of phenol aralkyl resin as represented by the following expression:                          where R 1 , R 2 , R 3 , and R 4  denote a hydrogen atom, an alkyl group having 1-8 carbon atoms, or a halogen atom, m is an integer of 1-4, and n is a real number of 0 or larger and less than 1, and    (8) a polyamine.    
     
     
         27 . An epoxy resin composition for fiber reinforced composite material according to  claim 26  wherein the component (8) is a liquid polyamine.  
     
     
         28 . An epoxy resin composition for fiber reinforced composite material according to  claim 26  wherein the component (8) is an aromatic polyamine.  
     
     
         29 . An epoxy resin composition for fiber reinforced composite material characterized in that the epoxy resin composition comprises an epoxy resin and an aromatic polyamine, has an initial viscosity at 80° C. of 1-500 MPa·s, and after being cured for two hours at 180° C. and immersed in boiling water for 48 hours, the cured product has a glass transition temperature of 130° C. or more.  
     
     
         30 . An epoxy resin composition for fiber reinforced composite material according to  claim 29 , wherein the cured product of the epoxy resin composition obtained by being cured for two hours at 180° C., has a flexural modulus at 82° C. of 2.3 GPa or more, after being immersed in boiling water for 48 hours.  
     
     
         31 . An epoxy resin composition for fiber reinforced composite material according to  claim 29 , wherein the cured product of the epoxy resin composition has a theoretical molecular weight between crosslinking points in the range of 250-350 g/mol.  
     
     
         32 . An epoxy resin composition for fiber reinforced composite material according to  claim 1 , wherein the epoxy resin composition is produced by mixing the following two liquids: 
 liquid (A3): component (9) or component (10) as specified below,    liquid (B3): a liquid comprising aromatic polyamine,    component (9): at least an epoxy selected from the group of N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane, and its alkyl-substituted derivatives, and    component (10): at least an epoxy selected from the group of N,N-diglycidyl aniline, and its alkyl-substituted derivatives.    
     
     
         33 . An epoxy resin composition for fiber reinforced composite material according to  claim 32 , wherein the epoxy resin composition has an initial viscosity at 80° C. of 1-500 MPa·s.  
     
     
         34 . An epoxy resin composition for fiber reinforced composite material according to  claim 32 , wherein the components (9) and (10) account for 30-90 wt % and 10-30 wt %, respectively, of the entire epoxy resin.  
     
     
         35 . A production method for fiber reinforced composite material that comprises impregnating reinforcing fiber with an epoxy resin composition of  claim 1 , followed by heating for curing.  
     
     
         36 . A production method for fiber reinforced composite material according to  claim 35  that comprises impregnating reinforcing fiber with an epoxy resin composition of  claim 1  at 40-90° C., precuring it at 80-140° C. , and aftercuring it at 170-190° C.  
     
     
         37 . A fiber reinforced composite material comprising a cured product of an epoxy resin composition of  claim 1 , and reinforcing fiber.  
     
     
         38 . A fiber reinforced composite material according to  claim 37  wherein reinforcing fiber accounts for 50-80% by volume.  
     
     
         39 . A production method for fiber reinforced composite material that comprises impregnating reinforcing fiber with an epoxy resin composition of  claim 14 , followed by heating for curing.  
     
     
         40 . A production method for fiber reinforced composite material according to  claim 39  that comprises impregnating reinforcing fiber with an epoxy resin composition of  claim 14  at 40-90° C., precuring it at 80-140° C. , and aftercuring it at 170-190° C.  
     
     
         41 . A fiber reinforced composite material comprising a cured product of an epoxy resin composition of  claim 14 , and reinforcing fiber.  
     
     
         42 . A fiber reinforced composite material according to  claim 41  wherein reinforcing fiber accounts for 50-85% by volume.  
     
     
         43 . A production method for fiber reinforced composite material characterized in that the production method comprises impregnating reinforcing fiber with an epoxy resin composition of  claim 29 , followed by heating for curing.  
     
     
         44 . A production method for fiber reinforced composite material according to  claim 43 , wherein the production method comprises impregnating reinforcing fiber with an epoxy resin composition of  claim 29  at 40-90° C., precuring it at 80-140° C., and aftercuring it at 170-190° C.  
     
     
         45 . Fiber reinforced composite material comprising a cured product of an epoxy resin composition of  claim 29 , and reinforcing fiber.  
     
     
         46 . Fiber reinforced composite material according to  claim 45  wherein reinforcing fiber accounts for 50-85% by volume.  
     
     
         47 . A production method for fiber reinforced composite material characterized in that the production method comprises impregnating reinforcing fiber with an epoxy resin composition of  claim 32 , followed by heating for curing.  
     
     
         48 . A production method for fiber reinforced composite material according to  claim 47 , wherein the production method comprises impregnating reinforcing fiber with an epoxy resin composition of  claim 32  at 40-90° C., precuring it at 80-140° C., and aftercuring it at 170-190° C.  
     
     
         49 . A fiber reinforced composite material comprising a cured product of an epoxy resin composition of  claim 32 , and reinforcing fiber.  
     
     
         50 . A fiber reinforced composite material according to  claim 49  wherein reinforcing fiber accounts for 50-85% by volume.