WO2025210429A1

WO2025210429A1 - Epoxy resin composition, resin film, prepreg, fiber-reinforced composite material, decomposition method of cured material and decomposed product

Info

Publication number: WO2025210429A1
Application number: PCT/IB2025/052845
Authority: WO
Inventors: Koji Furukawa
Original assignee: Toray Industries Inc; Toray Composite Materials America Inc
Current assignee: Toray Industries Inc; Toray Composite Materials America Inc
Priority date: 2024-03-30
Filing date: 2025-03-18
Publication date: 2025-10-09
Anticipated expiration: 2026-09-30

Abstract

A curable epoxy resin composition is described that comprises the following components [A], [B] and [C], wherein the resin composition comprises the reaction product of components [A] and [B] as component [D], and optionally comprises the component [B1] as component [B] included in component [D]; [A]: at least one epoxy resin; [B]: at least one amine compound; [C]: at least one curing agent other than component [B]; [B1]: at least one amine compound containing the structure represented by following formula (I) or (II) in a molecule (I) (II) wherein the epoxy resin composition as cured has a viscosity suitable for handling, excellent reaction stability, and excellent re-shapeability and easy degradation after curing, which can be used for resin films, fiber-reinforced composite materials, prepregs formed by impregnating the curable epoxy resin composition into reinforcing fibers, and fiber-reinforced composite materials containing the curable epoxy resin composition and reinforcing fibers. Also described is a process for recycling a product comprising the epoxy resin composition as cured and a fiber-reinforced composite material, wherein the process includes immersing the product in an acidic solvent at a temperature in the range of 25 to 200°C under conditions to remove the cured epoxy resin from the product.

Description

2102131-000636 -1- EPOXY RESIN COMPOSITION, RESIN FILM, PREPREG, FIBER-REINFORCED COMPOSITE MATERIAL, DECOMPOSITION METHOD OF CURED MATERIAL AND DECOMPOSED PRODUCT Cross-Reference to Related Applications This application claims the benefit of priority of United States Provisional Application No. 63/572,228, filed on March 30, 2024, and United States Provisional Application No. 63/755,746, filed on February 7, 2025, the contents of both of which are incorporated herein by reference in their entireties for all purposes. Field of the Invention This invention relates to an epoxy resin composition that combines viscosity in a range suitable for handling, excellent reaction stability, low exothermic heat generation during curing, and excellent re-shapeability and easy degradation after curing. The epoxy resin composition can be used in numerous applications, such as for resin films, fiber-reinforced composite materials, prepregs formed by impregnating the epoxy resin composition into reinforcing fibers, and fiber-reinforced composite materials containing the epoxy resin composition and reinforcing fibers. This invention also relates to a process for recycling cured epoxy resin compositions present in a product, wherein the process includes immersing the product in an acidic solvent at a temperature in the range of 25 to 200°C under conditions sufficient to remove the cured epoxy resin from the product, and to a decomposed product obtained by that process. Background of the Invention Fiber-reinforced composite materials containing reinforcing fibers (such as carbon fibers or glass fibers), and a matrix resin (such as an epoxy resin or a phenolic resin), have heretofore found application in fields such as aerospace, automobiles, rail cars, marine vessels, civil engineering and construction, and sporting goods since they are lightweight but exhibit excellent mechanical properties such as strength, rigidity, heat resistance and corrosion resistance. For applications which require high performance, a fiber-reinforced composite material containing continuous reinforcing fibers is a frequent choice. As the reinforcing fibers, carbon fibers exhibit excellent specific strength and specific modulus. As a matrix resin, a thermosetting resin, particularly an epoxy resin which adheres to carbon fibers, exhibits heat resistance, elastic modulus, chemical resistance, and low cure shrinkage, is often selected. However, due to the heat and chemical resistance resulting from its irreversible curing process, it is difficult to degrade cured epoxy resins and to recycle resin degradation products and reinforcing fibers at the end of the life cycle of cured resins 2102131-000636 -2- and fiber-reinforced materials. As a result, most epoxy resins are disposed of in landfills or incinerated at high temperatures of several hundred degrees Celsius. The challenge is to establish recycling methods that can reduce these negative environmental impacts and energy costs. Summary of the Invention In order to easily degrade epoxy resins in acidic solvents, techniques are described that use components with readily degradable bonds in epoxy resin compositions. WO 2013/184827 A1 describes epoxy resin compositions containing amine compounds with degradable bonds in the molecule. Also, WO 2020/161538 A1 describes epoxy resin compositions containing epoxy compounds with degradable bonds in the molecule. These technologies enable the previously difficult decomposition and recycling of cured epoxy resins to be achieved at relatively low temperatures in acetic acid solutions. On the other hand, when using these resin compositions as resin films, prepregs, or fiber-reinforced composites, it may be necessary or desirable to adjust the viscosity of the resin to a range suitable for a manufacturing process or for handling during use, but there is no such description or suggestion in these publications. In general, other components, such as thermoplastic resins, may be blended to adjust the viscosity of the epoxy resin composition, but blending high molecular weight components that are not degradable in the epoxy resin composition may undesirably impair the degradability of the readily degradable epoxy resin composition and may also make it difficult to recover the degradation products, A method of pre-reacting epoxy resins with amine compounds for the purpose of adjusting the viscosity of the resins to a range suitable for a manufacturing process and for handling during use is disclosed in WO2013/081058 A1. However, no consideration is given to achieving excellent reaction stability or low exothermic heat generation during curing, or the degradability and re-shapeability of the resulting cured product. To solve the aforementioned problems, the inventors have discovered a curable epoxy resin composition containing the following components [A], [B] and [C], wherein the resin composition comprises the reaction product of components [A] and [B] (referred to as component [D]) and component [B1] included in component [D]; [A]: at least one epoxy resin; [B]: at least one amine compound; [C]: at least one curing agent other than component [B]; [B1]: at least one amine compound containing a structure represented by formula (I) or (II). 2102131-000636 -3- (I) (II) Another aspect the following components [A], [B] and [C], wherein the resin composition comprises the reaction product of components [A] and [B](referred to as component [D]), wherein the rubber state elastic modulus of the cured product obtained by DMA (dynamic mechanical analysis) is 5.0 MPa or less: [A]: at least one epoxy resin; [B]: at least one amine compound; [C]: at least one curing agent other than component [B]. Another aspect relates to a curable epoxy resin composition containing the following components [A], [B] and [C], wherein the resin composition comprises the reaction product of components [A] and [B] (defined as component [D]), wherein during curing of the composition, the curing calorific value measured by differential scanning calorimetry (DSC) at a heating rate of 10° C / min is 240 J/g or less.; [A]: at least one epoxy resin; [B]: at least one amine compound; [C]: at least one curing agent other than component [B]. In an embodiment, a prepreg comprises reinforcing fiber bundles impregnated with an epoxy resin composition as disclosed herein. In an embodiment, a fiber-reinforced composite material is obtained by curing a prepreg as disclosed herein. In an embodiment, a fiber-reinforced composite material comprises a cured epoxy resin product obtained by curing a mixture comprising an epoxy resin composition as disclosed herein, and a reinforcing fiber. In an embodiment, a resin film comprises an epoxy resin composition as disclosed herein. Another embodiment is a process for recycling a product comprising the epoxy resin composition as cured and a fiber-reinforced composite material, wherein the process includes immersing the cured product in an acidic solvent at a temperature in the range of 25 to 200°C under conditions to remove the epoxy resin composition from the product, wherein the epoxy resin composition is formed from a curable epoxy resin composition comprising the following components [A], [B] and [C], wherein the resin composition comprises the reaction product of components [A] and [B] as component [D]; 2102131-000636 -4- [A]: at least one epoxy resin; [B]: at least one amine compound; [C]: at least one curing agent other than component [B]. Another embodiment is a process for recycling a product comprising the epoxy resin composition as cured, wherein the process includes immersing the product in an acidic solvent at a temperature in the range of 25 to 200°C under conditions to remove the epoxy resin composition from the product, wherein the epoxy resin composition is formed from a curable epoxy resin composition comprising components [A], [B] and [C], and wherein the resin composition comprises the reaction product of components [A] and [B] as component [D], and wherein the curable epoxy resin composition comprises the following component [B1] as component [B] included in component [D]; In an embodiment, the resin decomposition product is obtained by the process as disclosed herein. In an embodiment, the fiber material is obtained by the process as disclosed herein. Detailed Description of Embodiments of the Invention All publications, patents, and patent applications cited in this specification are hereby incorporated by reference in their entireties for all purposes. The articles “a” and “an” are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, “a polymer resin” means one polymer resin or more than one polymer resin. Any ranges cited herein are inclusive. The terms “substantially” and “about” are used to describe and account for small fluctuations. For example, they can refer to amounts or quantities that differ from a stated value by less than or equal to ±5%. Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Unless otherwise specified, “room temperature” as used herein refers to a temperature of 23 °C. As used herein, the term, “fiber-reinforced composite material” may be used interchangeably with the terms “fiber-reinforced composite,” “fiber-reinforced polymer material,” “fiber-reinforced polymer,” “fiber-reinforced plastic material,” and “fiber- reinforced plastic.” 2102131-000636 -5- This invention relates to an epoxy resin composition that combines viscosity in a range suitable for handling, excellent reaction stability, low exothermic heat generation during curing, and excellent re-shapeability and easy degradation after curing. The epoxy resin composition can be used in numerous applications, such as for resin films, fiber-reinforced composite materials, prepregs formed by impregnating the epoxy resin composition into reinforcing fibers, and fiber-reinforced composite materials containing the epoxy resin composition and reinforcing fibers. This invention also relates to a process for recycling cured epoxy resin compositions present in a product, wherein the process includes immersing the product in an acidic solvent at a temperature in the range of 25 to 200°C under conditions sufficient to remove the cured epoxy resin from the product, and to a decomposed product obtained by that process. The epoxy resin composition, the prepreg, and the carbon fiber-reinforced composite material of the present disclosure are described in detail below. Component [A] The [A] in the present invention is an epoxy resin. The epoxy the present invention are not limited to, but include, for example, bisphenol epoxy resins (such as bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol AD epoxy resin, bisphenol S epoxy resin, tetrabromobisphenol A brominated epoxy resins (such as tetrabromobisphenol A diglycidyl ether)), epoxy resins with a biphenyl skeleton, epoxy resins with a naphthalene skeleton, epoxy resins with a fluorene skeleton, epoxy resins with a dicyclopentadiene skeleton, phenolic novolac epoxy resins, cresol novolac epoxy resins, N,N,O-triglycidyl-m-aminophenol, N,N,O- triglycidyl-p-aminophenol, N,N,O-triglycidyl-4-amino-3-methylphenol, N,N,N ',N'- tetraglycidyl-4,4'-methylenedianiline, N,N,N',N'-tetraglycidyl-2,2'-diethyl-4,4'- methylenedianiline, N,N,N',N'-tetraglycidyl-m-xylylenediamine, N,N-diglycidylaniline, N,N N-diglycidyl-o-toluidine, glycidylamine epoxy resins, resorcinol diglycidyl ether, and triglycidyl isocyanurate. As the epoxy resin of component [A], it is preferable to use a compound having two epoxy groups in the molecule. Having two epoxy groups prevents the crosslink density of the resulting resin cured product from becoming too high, and the effects of the present invention, such as excellent degradability and re-shapeability, can be obtained, and heat generation during curing can also be suppressed. As the epoxy resin of component [A], epoxy resins containing three or more epoxy groups in one molecule may be blended, and epoxy resins containing one epoxy group in one molecule may also be blended. These epoxy resins may be used alone or in combination. 2102131-000636 -6- Component [B] The component [B] of the invention is an amine compound, which functions as a curing agent that reacts with the epoxy resin. The amine compound may be selected from, but is not limited to, aliphatic amines, aromatic amines, and mixtures thereof. When the component [B] is an aliphatic amine, the pre-reaction with the component [A] described below can easily proceed at a low temperature, which is preferred because it reduces energy costs. When the component [B] is an aromatic amine, it is preferred because the resin composition obtained has excellent viscosity stability and the cured material obtained has excellent heat resistance and toughness. When the component [B] is a monoamine or diamine, it is preferred because of the excellent degradability of the resulting cured product. When the constituent [B] is a trifunctional or higher polyamine, it is preferred because the viscosity of the epoxy resin composition can be efficiently increased to a viscosity suitable for prepreg applications even with a small amount of pre-reactant. As a preferred form of the invention, the resin composition comprises the following component [B1] as component [B] included in component [D]. [B1]: At least one amine compound containing the structure represented by following formula (I) or (II) in a molecule. (_I) ^(II) The structure is incorporated in the cured product of the epoxy resin obtained by including the component [B1]. In this embodiment, [B1] is a subset of [B] such that the composition includes at least one amine compound [B] and at least one of the at least one amine compound [B] is [B1]. Since this structure can be easily decomposed by treatment with the acid solution described below, the cured product of the epoxy resin has excellent degradability. Here, depending on the type of component [B1] used, the reactivity with epoxy resin, component [A], may be too high, and the resin viscosity change over time at the manufacturing process temperature of resin film or prepreg, for example, 60°C, may be too large, making the epoxy resin composition using it unsuitable for prepreg applications. In response to such a problem, the inventors have found that by using the component [D] in which this component [B1] is pre-reacted with the component [A], it is surprisingly possible to adjust the resin viscosity to a level suitable for the manufacturing process of resin films and prepregs while maintaining the excellent 2102131-000636 -7- degradability of the cured product, and the resin viscosity stability at 60°C can also be improved. Another form or aspect of this invention according to exemplary embodiments is an epoxy resin composition in which the component [B1] and the component [A] are blended without prior reaction, each unreacted. By blending the component [B1] and the component [A] without pre-reaction of them, the epoxy resin composition can be suitably used in processes that require relatively low resin viscosity, such as resin infusion applications, and the resulting resin cured product or fiber-reinforced composite material has excellent re-shapeability. Components [B1] include, but are not limited to, for example, 2-[2-(2- aminoethoxy)propan-2-yloxy]ethanamine, 1,1'-(propane-2,2-diylbis(oxy))bis(propan- 2-amine), 1,1'-(propane-2,2-diylbis(oxy))bis(butan-2-amine), 1,1'-(propane-2,2- diylbis(oxy))bis(2-methylpropan-2-amine), 2,2',2''- ((methylsilanetriyl)tris(oxy))tris(propan-1-amine), 1,1',1''- ((methylsilanetriyl)tris(oxy))tris(butan-2-amine), 1,1',1''- ((methylsilanetriyl)tris(oxy))tris(2-methylpropan-2-amine), and the amine compounds listed in, for example,. WO2012071896 A1, WO2013184827 A1, WO2015054698 A1, WO2019240840A1 and WO2019240841A1. The [B1] amine compounds may be used alone or in combination. Component [C] [C] is a curing agent different from the component [B] and can to the requirements of the application as long as it is a compound that reacts with epoxy resin. When the epoxy resin composition contains component [D] as described below and does not contain unreacted component [B] separately from component [D], the component [B] in component [D] has already been consumed by the preliminary reaction, and the curing reaction of the resin composition proceeds by the reaction between component [C], the curing agent, and component [A], the epoxy resin. On the other hand, if the epoxy resin composition does not contain component [D] or contains unreacted component [B] separately from component [D], the curing reaction of the composition proceeds by competition between the reaction of component [B] with component [A], the epoxy resin, and the reaction of component [C] with component [A]. The curing agent can be selected from, for example, but not limited to, amine compounds, hydrazide compounds, phenol compounds, thiol compounds, acid anhydrides, isocyanate compounds, cyanate ester compounds, and mixtures thereof. These curing agents may be used singly or two or more may be used in combination. 2102131-000636 -8- When mixed with other components, they may be in powder or liquid form, or powdered and liquid curing agents may be mixed together. It is preferred to include an aromatic amine compound (referred to as [C1]) as the component [C] of the present invention. The inclusion of component [C1] is preferred because it provides excellent viscosity stability of the epoxy resin composition and high elastic modulus after curing. In this embodiment, [C1] is a subset of [C] such that the composition includes at least one curing agent [C] and at least one of the at least one curing agent [C] is [C1]. Examples of such aromatic amine compounds include, but are not limited to, meta-phenylene diamine, diaminodiphenyl methane, diaminodiphenyl sulfone, meta- xylylene diamine, (para-phenylene methylene) dianiline, 4,4'-methylenebis[N-sec- butylaniline], N,N'-di-sec-buthyl-p-phenylendiamine, diethyltoluendiamine, dimethylthiotoluendiamine, various derivatives thereof such as alkyl-substituted derivatives, and various isomers having amino groups at different positions. Specific examples of suitable aromatic amine compounds include, but are not limited to, SEIKACURE-S (manufactured by Wakayama Seika Kogyo Co., Ltd.), ARADUR^® 976-1, ARADUR^® 9664-1, ARADUR^® 9719-1 (all manufactured by Huntsman Corporation), 3,3'-DAS (manufactured by Mitsui Chemicals, Inc.), Primacure^® M-DIPA, and Primacure^® M-MIPA (both manufactured by Arxada), Unilink 4200, Unilink 4100 (both manufactured by Dorf Ketal Chemicals LLC). It is preferred to include a phenolic compound (referred to as [C2]) as a component [C] of the present invention. The inclusion of component [C2] is preferred because it provides excellent reactivity of the epoxy resin composition, viscosity stability, and high elastic modulus after curing. Examples of such phenol compounds include, but are not limited to, bisphenol derivatives, dihydroxybenzophenone derivatives, dihydroxybiphenyl derivatives, dihydroxybenzene derivatives, naphthol derivatives, and dihydroxynaphthalene derivatives. Specific examples include 2,4-dihydroxybenzophenone, 4,4'- dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'- methylenebis(6-tert-butyl-4-ethylphenol), 4,4'-thiobis(6-tert-butyl-m-cresol), 4,4'- butylidenebis(6-tert-butyl-m-cresol), bis(4-hydroxyphenyl) sulfone, 9,9’-bis(4- hydroxyphenyl)fluorene, 9,9-bis(3-methyl-4-hydroxyphenyl)fluorene, 9,9’-bis(3-allyl-4- hydroxyphenyl)fluorene, 4,4'-dihydroxybiphenyl, tetrabromobisphenol a, 4,4’- dihydroxydiphenyl ether, 4,4’-thiodiphenol, 2,2'-dihydroxybiphenyl, 1,1'-bi-2-naphthol, 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2'-dihydroxy-4,4'- dimethoxybenzophenone, 2,2'-methylenebis[6-(1-methylcyclohexyl)-p-cresol], 2,2'- 2102131-000636 -9- methylenebis(6-tert-butyl-p-cresol), diethyl 2,5-dihydroxyterephthalate, 1,4- dihydroxyanthraquinone, 3,5-di-tert-butylpyrocatechol, tert-butylhydroquinone, methylhydroquinone, 2-methylresorcinol, 1,6-dihydroxynaphthalene, 2,3- dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 3,3,3’,3’-tetramethyl-1,1’- spirobiindan-6,6’-diol, 3-(4-hydroxyphenyl)-1,1,3-trimethyl-5-indanol, o- cresolphthalein, fluorescein, 2’,7’-dichlorofluorescein, 2,5-dihydroxy-1,4-benzoquinone, 3,3',5,5'-tetra-tert-butyl-[1,1'-biphenyl]-2,2'-diol, bis(4-hydroxy-3-methylphenyl) sulfide, bis(3-hydroxyphenyl) disulfide, 2,2-diallyl-4,4'-biphenol, 2,2'-diallylbisphenol a, 4,4'-sulfonylbis(2-allylphenol), 4-tert-butylcatechol, 2,5-di-tert-butylhydroquinone, 2,5- di-tert-amylhydroquinone, 2,2'-methylenebis(6-cyclohexyl-p-cresol), 2,2'- methylenebis(6-tert-butyl-p-cresol), 4,4'-(3,3,5-trimethylcyclohexane-1,1- diyl)diphenol, various derivatives thereof such as alkyl-substituted derivatives, and various isomers having phenol groups at different positions. It is preferable to include a thiol compound (referred to as [C3]) as a component [C] of the present invention. The inclusion of the constituent [C3] is preferred because it provides excellent reactivity of the epoxy resin composition and high elastic modulus after curing. Examples of such thiol compounds include, but are not limited to, trimethylol propane tris(3-mercaptobutylate), 1,4-bis(3-mercaptobutyroyloxy)butane, 1,3,5-tris [2-(3-mercaptobutanoyloxy)ethyl]-1,3,5-triazine-2,4,6(1h,3h,5h)-trione, pentaerythritol tetrakis(3-mercaptobutylate), 4,4'-thiobisbenzenethiol, bismuthiol, 6- (dibutylamino)-1,3,5-triazine-2,4-dithiol, various derivatives thereof such as alkyl- substituted derivatives, and various isomers having thiol groups at different positions. The constituent [C] of the present invention is preferably a compound having two active hydrogens in the molecule that react with the epoxy resin. By having two active hydrogens that react with the epoxy resin, component [C] acts as a chain-length extender and does not form cross-linking points in the resulting resin cured product, thus allowing the epoxy resin to be cured without impairing the degradability that is an advantage of the present invention. In addition, the resulting cured material has excellent remolding properties, and heat generation during curing can be suppressed. Examples of compounds having two active hydrogens in the molecule that react with epoxy resins include monofunctional primary amine compounds, bifunctional secondary amine compounds, bifunctional phenol compounds, monofunctional hydrazide compounds, bifunctional thiol compounds, monofunctional acid anhydrides, bifunctional isocyanate compounds, bifunctional cyanate ester compounds and mixtures thereof. Furthermore, it is particularly preferred to use a compound having two active hydrogens in the molecule that react with the epoxy resin as the component [C] of the 2102131-000636 -10- present invention, in combination with a compound having two epoxy groups in the molecule as the component [A] mentioned above. In this case, since the cross-linking point in the epoxy resin cured product formed from the components [A], [B1], and [C] is formed only by the component [B1], the resin cured product is particularly easily decomposed when the structure of formula (I) or (II) in the component [B1] is decomposed by acid solution treatment. In other words, the structure can be effectively decomposed in a short time even at low temperatures or at low acid concentrations, and the energy cost required for decomposition can be reduced. Component [D] The component [D] of this invention is the reaction product of component [A] [B]. As a form or aspect of the invention, by containing component [D], the epoxy resin composition of the invention can have a viscosity suitable for the manufacturing process of resin films and prepregs without blending other components such as a thermoplastic resin, thereby reducing costs and procedures in the production of the epoxy resin composition. In addition, by containing component [D], a resin composition with excellent viscosity stability can be obtained compared to when component [B], which is not reacted with component [A], is used alone. Furthermore, since the amount of heat generated from curing the epoxy resin composition can be reduced, the rise in member temperature due to heat storage during curing of the resin and prepreg can be suppressed, and degradation due to thermal decomposition can be prevented. It is also desirable because a cured material with a uniform degree of cure and minimal differences in physical properties can be obtained within a member, even when members of different sizes and thicknesses are molded. The reaction product of component [A] and component [B] can be obtained by heating mixtures of [A] and [B], blended in any ratio, at a temperature at which the reaction proceeds. When this method is used, unreacted component [A] and component [B] may remain in the reaction product, but there is no particular need to remove these residues. The heating temperature can be selected according to the type of component [A] and [B] used, but it is preferable to use a heating temperature of 80°C or higher, 100°C or higher, 120°C or higher, 130°C or higher, 140°C or higher, or 160°C or higher. The higher the heating temperature in this range, the more rapidly the reaction proceeds and the reaction product can be obtained in a shorter time. The preferred heating temperature is 200°C or less, and even more preferably 180°C or less. A heating temperature in this range is desirable because it prevents undesirable thermal decomposition due to heating and also reduces the energy cost required. The component [D] in one embodiment of the invention is the reaction product of component [A] and component [B1]. That is, component [D] has the structure of 2102131-000636 -11- formula (I) or (II) in the molecule. This gives the resulting cured product excellent degradability. Specific non-limiting examples of component [D] are described below using chemical structural formulas. These chemical structures are examples and do not limit the scope of the invention. For example, when a bisphenol A epoxy resin listed in Formula (III) is used as component [A] and a bifunctional amine listed in Formula (IV) is used as component [B1], the four active hydrogens in component [B1] react with the epoxy groups in component [A] by the above preliminary reaction procedure to form component [D] as in Formula (V). Although the chemical structure of component [D] obtained when all four active hydrogens in [B1] react is shown here, only one, two, or three of the active hydrogens in [B1] may react for example, and the system may contain unreacted active hydrogens in component [B1] and unreacted component [A]. In addition, the component [D] may be an oligomer in which the terminal epoxy group derived from component [A] has further reacted with another component [B1] molecule in its chemical structure. (IV) (V) A preferred form of the present invention is a preparation process in which component [A] and component [B] are pre-reacted to obtain component [D], which is a reactant, followed by further blending component [C] to obtain an epoxy resin composition. The epoxy resin composition obtained in the above process is preferred because the stability of the resin viscosity at 60°C is increased, the resin viscosity 2102131-000636 -12- becomes suitable for prepreg applications, and the amount of heat generated during curing is also reduced. Component [E] The component [E] is a catalyst. It can be included in the epoxy resin from the viewpoint of increasing the reactivity of the epoxy resin and cure in a short time and increasing the heat resistance, toughness and elongation of the cured product. As a catalyst, it is preferable to use at least one selected from the group consisting of an aromatic urea compound, an imidazole derivative, and a phosphorus compound from the viewpoint of achieving both storage stability and curability of the epoxy resin composition. The aromatic urea compounds mentioned above include, for example, 3- phenyl-1,1-dimethylurea, 3-(3-chloro-43-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,13-(3,4-dichlorophenyl)-1,1-dimethylurea, toluene bis dimethylurea, and others. The imidazole derivatives mentioned above include, for example, 1-benzyl-2- methylimidazole, 1-benzyl-2-ethylimidazole, 1-cyanoethyl-2-methylimidazole, 1- cyanoethyl-2-ethyl-41-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4- methylimidazole, 1-cyanoethyl-2-phenylimidazole, and others. The phosphorus compounds mentioned above include, for example, triphenylphosphine, tri-o-tolylphosphine, tris(p-methoxyphenyl)phosphine, triphenylphosphine triphenylborane, tetraphenylphosphonium tetraphenylborate, and others. The amount of component [E] is preferably 0.1 parts by mass or more, 0.3 parts by mass or more, or 0.5 parts by mass or more to 100 parts by mass of epoxy resin. The greater the amount of component [E] in this range, the better the curability of the epoxy resin composition. The amount of component [E] is preferably 5 parts by mass or less, 3 parts by mass or less, and 1.5 parts by mass or less per 100 parts by mass of epoxy resin. The smaller the amount of component [E] in this range, the better the viscosity stability of the epoxy resin composition. The resin compositions of the present invention can be blended with thermosetting resin particles, thermoplastic resins soluble in epoxy resin, or inorganic fillers such as silica particles, carbon particles, clay, carbon nanotubes, graphene, and metal powders to the extent that the effect of the invention is not hindered. As a thermoplastic resin, a thermoplastic resin having chemical bonds selected from the group consisting of carbon-carbon bonds, amide bonds, imide bonds, ester bonds, ether bonds, carbonate bonds, urethane bonds, thioether bonds, sulfone bonds and/or carbonyl bonds in the main chain of the thermoplastic resin is preferred. 2102131-000636 -13- Further, the thermoplastic resin can also have a partially cross-linked structure and be crystalline or amorphous. In particular, it is suitable or preferred that at least one thermoplastic resin selected from the group consisting of polyamides, polycarbonates, polyacetals, polyphenylene oxides, polyphenylene sulfides, polyallylates, polyesters, polyamideimides, polyimides (including polyimides having a phenyltrimethylindane or phenylindane structure), polyetherimides, polysulfones, polyethersulfones, polyetherketones, polyetheretherketones, polyaramids, polyethernitriles, polyvinylformal and polybenzimidazoles is mixed or dissolved into the epoxy resin composition. In the resin composition of the present invention, it is preferable that the ratio of each component in component [D] satisfies (F1); (F1): (the (number of moles of active hydrogens contained in component [B]) / the number of moles of epoxy groups of component [A]) ≦ 0.4. If the value of ((the number of moles of active hydrogens contained in component [B]) / the number of moles of epoxy groups of component [A]) is 0.4 or less, the viscosity of the epoxy resin composition does not become too high even if the component [A] and the component [B] react sufficiently, and it is suitable for mixing with other components. If the value of ((the number of moles of active hydrogens contained in component [B]) / the number of moles of epoxy groups of component [A]) is 0.1 or more, the cured material is insoluble in organic solvents such as acetone, which is desirable because the cured epoxy resin and fiber-reinforced composites are more resistant to such organic solvents in the operating environment. In the resin composition of the present invention, it is preferable that the blending ratio of each component satisfies (F2); (F2): 0.5 ≦ (the number of moles of active hydrogens contained in component [C] / the number of moles of epoxy groups of component [A]). If the value of (the number of moles of active hydrogens contained in component [C] / the number of moles of epoxy groups of component [A]) is 0.5 or more, preferably 0.6 or more, and even more preferably 0.7 or more, the formation of a crosslinked structure in the epoxy resin cured material is appropriate, and a cured material with excellent toughness and solvent resistance that can withstand trimming of parts, etc. is obtained. In addition, the rubber state modulus of the cured material becomes sufficiently low, i.e., the crosslink density becomes sufficiently low, which results in excellent reprocessing properties. If the value of (the number of moles of active hydrogens contained in component [C] / the number of moles of epoxy groups of component [A]) is 0.9 or less, preferably 0.8 or less, the formation of a crosslinked structure in the epoxy resin 2102131-000636 -14- cured material is appropriate, and a cured material with excellent toughness and solvent resistance that can withstand trimming of parts, etc. can be obtained. In the resin composition of the present invention, it is preferable that the blending ratio of each component satisfies (F3); (F3): 0.8 ≦ ((the number of moles of active hydrogens contained in component [B] + the number of moles of active hydrogens contained in component [C]) / the number of moles of epoxy groups of component [A]) ≦ 1.2. If the value of ((the number of moles of active hydrogens contained in component [B] + the number of moles of active hydrogens contained in component [C]) / the number of moles of epoxy groups of component [A]) is 0.8 or more, and preferably 0.9 or more, the formation of a crosslinked structure in the epoxy resin cured material is appropriate, and a cured material with excellent toughness and solvent resistance that can withstand trimming of parts, etc. is obtained. If the value of ((the number of moles of active hydrogens contained in component [B] + the number of moles of active hydrogens contained in component [C]) / the number of moles of epoxy groups of component [A]) is 1.2 or less, and preferably 1.1 or less, the formation of a crosslinked structure in the epoxy resin cured material is appropriate, and a cured material with excellent toughness and solvent resistance that can withstand trimming of parts, etc. is obtained. The rubber state elastic modulus of the cured material produced by curing the epoxy resin composition of the present invention should be 5.0 MPa or less in the dynamic viscoelasticity evaluation, and more preferably 4.0 MPa or less, 3.0 MPa or less, 2.0 MPa or less, and 1.0 MPa or less. The rubber state modulus of elasticity is said to be correlated with the crosslink density of the epoxy resin cured material, and the lower the rubber state modulus is in this range, the lower the crosslink density of the cured material is, meaning that the cured material has a crosslink structure with high deformation capacity. Surprisingly, the inventor found that when the dynamic viscoelastic modulus of the cured resin composition is within this range, the cured molding or fiber-reinforced composite material has excellent re-shapeability. The re- shapeability here refers to the ability to deform the shape of the cured molding by press molding or other methods when the cured molding is reheated to a temperature above the glass transition temperature, and to maintain the deformed shape when the temperature is lowered to a temperature below the glass transition temperature. The storage modulus of the cured material cured from the epoxy resin composition of the present invention at 40°C in the dynamic viscoelasticity evaluation should be 0.8 GPa or higher, more preferably 0.9 GPa or higher, and even more 2102131-000636 -15- preferably 1.0 GPa or higher. The higher the storage modulus in this range, the more rigid the cured material can be, and the wider the range of its applications. The ratio of the storage modulus at 40°C to the rubber state modulus (storage modulus at 40°C [Pa]/rubber state modulus [Pa]) in the dynamic viscoelasticity evaluation of the cured epoxy resin composition of the present invention should be 180 or more, more preferably 200 or more, 400 or more, 600 or more, 800 or more, 1000 or more, and 1500 or more. The larger the ratio of modulus of elasticity in the outer range, the more desirable it is because the cured material has both rigidity and re- shapeability at a high level, which further expands the range of its application. The rubber state elastic modulus and storage modulus at 40°C in the dynamic viscoelasticity evaluation of cured epoxy resin compositions of the present invention are measured in the DMA measurement method in the torsion mode according to ASTM D 5279 as follows. Using a viscoelasticity measuring device (ARES, TA instrument), DMA measurement is performed on a specimen of 2.0 mm thick, 12.7 mm wide, and 50 mm long in the temperature range of 40-280°C under a torsional vibration frequency of 1.0 Hz and a temperature increase rate of 5.0°C/min. The rubber state elastic modulus and storage modulus at 40°C are read. The rubber state modulus is the storage modulus in the temperature region above the glass transition temperature where the storage modulus has flattened out. The initial viscosity of the epoxy resin composition of the present invention at 60°C is preferably 1.0 Pa-s or higher, more preferably 5.0 Pa-s, 10 Pa-s, 15 Pa-s, 20 Pa-s, 25 Pa-s, 30 Pa-s or higher. The initial viscosity of the epoxy resin composition of the present invention at 60°C is preferably less than 2000 Pa-s, and more preferably less than 1000 Pa-s, 500 Pa-s, 400 Pa-s, 300 Pa-s, 200 Pa-s, 100 Pa-s or less. is within the approximate range, the resin flow during resin film and prepreg fabrication becomes appropriate, and resin film and prepreg with a uniform amount of resin can be obtained, which is desirable. In addition, handling of the obtained resin film or prepreg, such as tackiness and drape, is also desirable. The viscosity of the epoxy resin composition after holding at 60°C for 2 hours should be 5.0 times or less than the initial viscosity at 60°C. More preferably, it is 4.0 times or less, 3.0 times or less, 2.0 times or less, 1.5 times or less, and 1.2 times or less. The smaller the viscosity ratio is in the approximate range, the more desirable it is because the change in resin viscosity during resin film and prepreg fabrication can be suppressed and resin film and prepreg with a uniform resin content can be obtained. In addition, chemical reactions are less likely to progress when the resin film or prepreg is stored for a long period of time, resulting in excellent storage stability. 2102131-000636 -16- The viscosity of the epoxy resin composition is measured by the following method. Using a viscoelasticity measuring device (ARES, TA instrument) and parallel plates with a plate spacing of 0.6 mm, the complex viscosity η* of the epoxy resin composition was measured for 2 hours at a torsional vibration frequency of 0.5 Hz and a measurement temperature of 60°C. The initial viscosity at 60°C and the viscosity after 2 hours were respectively the initial viscosity and the viscosity after 2 hours at 60°C. The epoxy resin composition of the present invention preferably has a curing calorific value of less than 240 J/g as measured by differential scanning calorimetry (DSC) at a temperature increase rate of 10°C/min, and more preferably less than 230 J/g, 220 J/g, 190 J/g, 160 J/g and 130 J/g. The smaller the curing calorific value in the approximate range, the more the resin or prepreg can suppress the rise in member temperature due to heat storage during curing, thereby preventing degradation due to thermal decomposition. It is also desirable to obtain a cured product with a uniform degree of cure and minimal differences in physical properties within a member, even when members of different sizes and thicknesses are molded. The curing calorific value of the epoxy resin composition of the present invention can be determined from the peak area of the curing calorific curve obtained by raising the temperature from room temperature at a rate of 10°C/minute in a differential scanning calorimeter (DSC) in accordance with ASTM D 3418-15. The resin film is prepared by applying the described epoxy resin composition alone on release paper or release film, or by impregnating the substrate with the described epoxy resin composition. Preferred examples of base materials include carbon fiber, graphite fiber, aramid fiber, glass fiber, thermoplastic resin fiber, etc. Of these, glass fiber and thermoplastic resin fiber are particularly preferred. Resin films are made by various known methods, such as the wet method, in which epoxy resin is dissolved in a solvent such as methyl ethyl ketone or methanol to reduce the viscosity of the resin, and the solution is applied on release paper or release film or impregnated into the base material, the method of heating epoxy resin to reduce the viscosity of the resin, and the resin is applied on release paper or release film, or the method of impregnating the base material. The resulting resin film can be used as a surface resin layer to improve the surface quality of other components. It can also be used as an adhesive layer to bond other fiber-reinforced composites or between fiber-reinforced composites and other members. The resin film of the present invention is preferably used in combination with the cured product of epoxy resin or fiber reinforced composites of the present 2102131-000636 -17- invention. This is because the entire cured material including the resin film layer has excellent degradability and does not contain undissolved impurities after degradation. It is also desirable because the entire cured component including the resin film layer has excellent re-shapeability. It is also preferable to use the resin film in combination with cured conventional epoxy resins or fiber reinforced composites that are not degradable. This is because only the cured resin film layer is partially degradable under mild acidic conditions and can be recovered without degrading the cured conventional epoxy resin or fiber-reinforced composite material that is not degradable. The resin weight in the resin film is preferably 30 g/m² or more, more preferably 50 g/ m², 80 g/ m² or more. The higher the resin weight is, the fewer pinholes there are and the more uniformly the support can be covered with the epoxy resin composition, and the less likely it is to tear. On the other hand, the resin weight in the resin film is preferably 300 g/ m² or less, more preferably 200 g/ m², 150 g/ m² or less. The lower the resin weight is, the easier it is to improve the draping property of the sheet-like intermediate base material. The prepreg of the present invention is prepared by impregnating reinforcing fibers with the as described epoxy resin compositions as matrix resins. Preferred examples of the reinforced fibers include carbon fibers, graphite fibers, aramid fibers, glass fibers and the like, and among these fibers, carbon fibers are particularly preferred. The prepreg can be prepared by various commonly known methods, for example, by a wet method of dissolving a matrix resin in a solvent such as methyl ethyl ketone and methanol to reduce the viscosity of the resin and then impregnating reinforcing fiber bundles with the solution, or by a hot melting method of heating a matrix resin to reduce the viscosity of the resin and then impregnating reinforcing fiber bundles with the resin. In the wet method, the prepreg is prepared by immersing sizing agent- coated carbon fiber bundles in a solution containing a matrix resin, then pulling up the reinforcing fiber bundles, and evaporating the solvent using an oven or other units. 2102131-000636 -18- In the hot melting method, a prepreg is prepared by a method of directly impregnating reinforcing fiber bundles with a matrix resin having a viscosity lowered by heat or alternatively, by a method of preparing a coating film of a matrix resin composition on a release paper or the like, followed by superimposing the film on each side or on one side of the reinforcing carbon fiber bundles, and then applying heat and pressure to the film to impregnate the reinforcing fiber bundles with the matrix resin. The hot melting method is preferred over the wet method because no solvent remains in the prepreg. The reinforcing fiber cross-sectional density of a prepreg may be 50 to 1000 g/m², such as 100 to 1000 g/m², such as 200 to 1000 g/m². If the cross-sectional density is at least 50 g/m², there may be a need to laminate a small number of prepregs to secure the predetermined thickness when molding a fiber-reinforced composite material which may simplify the lamination process. If, on the other hand, the cross-sectional density is no more than 1000 g/m², the drapability of the prepreg remains good. The reinforcing fiber mass fraction of a prepreg may be 40 to 90% by mass in some embodiments, 50 to 85% by mass in other embodiments or even 60 to 80% by mass in still other embodiments. If the reinforcing fiber mass fraction is at least 40% by mass, there is sufficient fiber content to provide a fiber-reinforced composite material with excellent specific strength and specific modulus, as well as preventing the fiber-reinforced composite material from generating too much heat during the curing time. If the reinforcing fiber mass fraction is no more than 90% by mass, impregnation of the reinforcing fibers with the resin decreases the risk of a large number of voids forming in the fiber-reinforced composite material. The prepreg in this invention is preferably characterized by the inclusion of unidirectionally oriented discontinuous carbon fibers. The discontinuity of the carbon 2102131-000636 -19- fibers allows the prepreg to stretch in the fiber direction, preventing bridging (fiber sticking out) during curved surface forming of the prepreg laminate and suppressing wrinkle and void generation. Furthermore, it is particularly desirable to use the epoxy resin composition of the present invention as a matrix resin in a prepreg characterized by the inclusion of unidirectionally oriented discontinuous carbon fibers. Although epoxy cured materials with low crosslink density have excellent remolding properties on their own, by using them as matrix resins for fiber-reinforced composites containing unidirectionally oriented discontinuous carbon fibers, the restraints to deformation in the fiber direction are relaxed, resulting in fiber-reinforced composite materials with excellent re- shapeability even after curing compared to fiber-reinforced composites containing only continuous fibers. In addition, by using epoxy resin cured material with excellent degradability of this invention in combination with discontinuous carbon fibers above, the fiber material obtained after decomposing the fiber-reinforced composite material is already processed into short fibers instead of continuous fibers. The recovered fiber material is desirable because it can be easily reprocessed for reuse in other application such as the filler for other material or nonwoven material, simplifying the post- processing process. A prepreg characterized by the inclusion of unidirectionally oriented discontinuous carbon fibers can be made by known methods. For example, it can be obtained by inserting a prepreg sheet containing unidirectional continuous fibers into a roller cutter with blades arranged in a cylinder in the direction of the fibers and inserting intermittent straight incisions. 2102131-000636 -20- The method for forming a fiber-reinforced composite material by using a prepreg of the present invention is exemplified by a method of stacking prepregs and thermally hardening a matrix resin while applying pressure to the laminate. Application of heat and pressure under the prepreg lamination and molding method may be achieved by using a press molding method, an autoclave molding method, a bagging molding method, a wrapping tape method, an internal pressure molding method, or the like as appropriate. Autoclave molding is a method in which prepregs are laminated on a tool plate of a predetermined shape and then covered with bagging film, followed by curing, performed through the application of heat and pressure while air is drawn out of the laminate. This method allows precision control of the fiber orientation, as well as providing high-quality molded materials with excellent mechanical characteristics, due to a minimum void content. The pressure applied during the molding process may be 0.3 to 1.0 MPa, while the molding temperature may be in a range of 90 to 300 °C. The wrapping tape method is a method in which prepregs are wrapped around a mandrel or some other cored bar to form a tubular fiber-reinforced composite material. This method may be used to produce golf shafts, fishing poles and other rod shaped products. More specifically, the method involves the wrapping of prepregs around a mandrel using a wrapping tape made of thermoplastic film to wrap over the prepregs under tension for the purpose of securing the prepregs and applying pressure to them. After curing of the resin through heating inside an oven, the mandrel is removed to obtain a tubular body. The tension used to wrap the wrapping tape may be 20 to 100 N. The molding temperature may be in a range of 80 to 300 °C. The internal pressure forming method is a method in which a preform obtained by wrapping prepregs around a thermoplastic resin tube or some other internal 2102131-000636 -21- pressure applicator is set inside a metal mold, followed by the introduction of a high pressure gas into the internal pressure applicator to apply pressure, accompanied by the simultaneous heating of the metal mold to mold the prepregs. This method may be used when forming objects with complex shapes, such as golf shafts, bats, and tennis or badminton rackets. The pressure applied during the molding process may be in a range of 0.1 to 2.0 MPa. The molding temperature may be in a range between room temperature and 300 °C or in a range of 120 to 275 °C. The fiber-reinforced composite material produced from the prepreg of the present invention may have a class A surface as described herein. The term "class A surface" refers to a surface that exhibits extremely high finish quality characteristics free of aesthetic blemishes and defects. The fiber-reinforced composite materials that contain the cured epoxy resin compositions obtained from curing the epoxy resin compositions and the reinforcing fibers as described herein are advantageously used in sports applications, general industrial applications, and aeronautic and space applications. Sports applications in which these materials are advantageously used include, but are not limited to, golf shafts, fishing rods, tennis or badminton rackets, hockey sticks and ski poles. General industrial applications in which these materials are advantageously used include, but are not limited to, structural materials for vehicles (such as automobiles, bicycles, marine vessels and rail vehicles), drive shafts, leaf springs, windmill blades, pressure vessels, flywheels, papermaking rollers, roofing materials, cables, and repair/ reinforcement materials. This invention provides a process for recycling cured products of an epoxy resin composition and a fiber-reinforced composite material, wherein the process includes immersing the cured product in an acidic solvent, wherein the epoxy resin composition contains the following components [A], [B] and [C], wherein the resin 2102131-000636 -22- composition comprises the reaction product of components [A] and [B] as component [D]; [A]: At least one epoxy resin; [B]: At least one amine compound; [C]: At least one curing agent other than component [B]. Examples are shown below, but are not limited to this process. In one embodiment, cured products of an epoxy resin composition and a fiber-reinforced composite material are decomposed by an acidic solvent. The acidic solvent is a solvent containing a Lewis acid, for example, an acid selected from the group consisting of hydrochloric acid, acetic acid, lactic acid, formic acid, propionic acid, citric acid, methanesulfonic acid, p-toluenesulfonic acid, sulfuric acid, benzoic acid, and phthalic acid. The acid concentration in the acid solvent is preferably greater than 1 % by volume, and preferably greater than 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50% by volume. The higher the acid concentration, the more efficiently the cured products of an epoxy resin composition and a fiber-reinforced composite material are decomposed in a shorter time. Also, in one embodiment, cured products of an epoxy resin composition and a fiber-reinforced composite material are prepared in the presence of a solvent selected from the group consisting of methanol, ethanol, ethylene glycol, isopropyl alcohol, Butyl alcohol, pentanol, hexanol, heptanol, octanol, octanol alcohol, nonyl alcohol, etc., water, and combinations thereof. The acidic solution used in the process is preferably a mixture of an acid and an organic solvent. For example, methylene chloride, tetrahydrofuran, acetone, acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, etc. are used as organic solvents. N-methylpyrrolidone, etc. are used. The use of mixed solvents of acids and these organic solvents increases the affinity of the decomposition products to the solvent and promotes their diffusion into the solvent, resulting in more efficient decomposition. In one embodiment cured products of an epoxy resin composition and a fiber- reinforced composite material are decomposed by an acidic solution of 10% to 1000% by volume of the volume of the epoxy resin composition contained therein. by volume of the epoxy resin composition contained therein. The process of recycling cured products of an epoxy resin composition and a fiber-reinforced composite material is preferably carried out at temperatures in the range of 25 to 150°C. More preferred temperature ranges are above 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, and 120°C. The higher the process temperature, the more 2102131-000636 -23- quickly the cured products of an epoxy resin composition and a fiber-reinforced composite material can be decomposed. In one embodiment, cured products of an epoxy resin composition and a fiber- reinforced composite material are decomposed by heating in an acid solution for 10 minutes to 48 hours. of an epoxy resin composition and a fiber-reinforced composite material are decomposed by heating in an acid solution for 10 minutes to 12 hours. In some embodiments, the recycling process includes a process for recovering the decomposition products of the epoxy resin cured products via a filtration process and/or a precipitation process. The filtration process includes, for example, filtering the solution of the above process cured products of an epoxy resin composition and a fiber- reinforced composite material and recovering the contained fiber material. In the precipitation process, for example, the acid solution after decomposing the cured products of an epoxy resin composition and a fiber-reinforced composite material in the above process is neutralized with a basic compound to precipitate the resin decomposition products. The precipitation process includes, for example, neutralizing the acid solution with a basic compound to precipitate the resin decomposition products. The resin decomposition products of the present invention are resin products obtained by decomposing cured products of an epoxy resin composition and a fiber- reinforced composite material in the process described above. The degradation products of the present invention are fiber materials obtained by degrading a fiber-reinforced composite material in the process described above. Within this specification, embodiments have been described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without departing from the invention. For example, it will be appreciated that all preferred features described herein are applicable to all aspects of the invention described herein. Although the invention is illustrated and described herein with reference to specific embodiments, the scope of the invention is not intended to be limited by these embodiments. Rather, various modifications may be made within the scope and range of equivalents of the claims without departing from the invention. Examples 2102131-000636 -24- Embodiments of the present invention are now described in more detail by way of examples. The measurement of various properties was carried out using the methods described below. These properties were, unless otherwise noted, measured under environmental conditions comprising a temperature of 23 °C and a relative humidity of 50%. Prepregs were then made from the exemplary resins using a hot melt prepreg method. The components used in the working examples and comparative examples are as follows. <Component [A]> Epoxy 1: EPON™ 825 (bisphenol A type epoxy resin, manufactured by Miller- Stephenson Chemical Co., epoxy equivalent weight 187 g/eq); Epoxy 2: ARALDITE^® MY0816CH (Oxirane, 2,2'-[1,6- naphthalenediylbis(oxymethylene)]bis-, manufactured by Huntsman Corporation, epoxy equivalent weight 148 g/eq); Epoxy 3: EPICLON^® 830 (bisphenol F type epoxy resin, manufactured by DIC Corporation, epoxy equivalent weight 173 g/eq). <Component [B]> [B1] Amine 1: Recyclamine^® R 501 (2,2-Bis(2-amino-2- methylpropoxy)propane, manufactured by Aditya Birla Chemicals (Thailand) Limited., active hydrogen equivalent weight 55 g/eq); [B1] Amine 2: Recyclamine^® R 101 (2,2-Bis(2-aminoethoxy)propane, manufactured by Aditya Birla Chemicals (Thailand) Limited., active hydrogen equivalent weight 41 g/eq); [B1] Amine 3: Recyclamine^® R 805 (1,1',1''-((Methylsilanetriyl)tris(oxy))tris(2- methylpropan-2- amine), manufactured by Aditya Birla Chemicals (Thailand) Limited., active hydrogen equivalent weight 51 g/eq); Amine 4: JEFFAMINE^® T403 (Propylidynetrimethanol, propoxylated, reaction products with ammonia, manufactured by Huntsman Corporation, active hydrogen equivalent weight 81 g/eq). <Component [C]> [C1] Amine 5: Unilink 4200 (manufactured by Everchem specialty chemicals, active hydrogen equivalent weight 155 g/eq); [C2] Phenol 1: Compimide^® TM124 (2,2'-Bis(3-allyl-4-hydroxyphenyl)propane, manufactured by Evonik industries, active hydrogen equivalent weight 154 g/eq); [C2] Phenol 2: 4t-butylcatechol (manufactured by Tokyo Chemical Industry Co., Ltd., active hydrogen equivalent weight 83 g/eq); [C2] Phenol 3: 2,4-Dihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd., active hydrogen equivalent weight 107 g/eq); 2102131-000636 -25- [C2] Phenol 4: Tert-butylhydroquinone (manufactured by Tokyo Chemical Industry Co., Ltd., active hydrogen equivalent weight 83 g/eq); [C3] Thiol : Bismuthiol (manufactured by Tokyo Chemical Industry Co., Ltd., active hydrogen equivalent weight 75 g/eq). <Component [E]> Urea 1: DYHARD^® UR200 (DCMU. 3-(3,4-dichlorophenyl)-1,1-dimethylurea, manufactured by AlzChem LLC). (1) Preparation of epoxy resin composition The epoxy resin of component [A] and the amine compound of component [B] were put into a kneader in the amounts and proportions shown in Table 1, and heated to 135°C while mixing, and then stirred for 90 minutes to pre-react them to obtain viscous liquid component [D]. The liquid was cooled to 70°C with stirring, and the hardener of component [C] was added. The liquid was cooled to 60°C while stirring, component [E] catalyst was added, and stirred for another 10 minutes to obtain an epoxy resin composition. (2) Preparation of epoxy resin cured product The epoxy resin composition obtained in (1) was defoamed in a vacuum and cured in a mold set to a thickness of 2 mm using a 2 mm thick Teflon^TM spacer to obtain a 2 mm thick plate-like resin cured material. The curing conditions were either A or B below, depending on the curing agent used. Curing condition A: Ramp rate 1.7C/min, cured at 135°C for 2 hours. Curing condition B: Ramp rate 1.7C/min, cured at 180°C for 2 hours. (3) DMA (Dynamic mechanical analysis) measurement of epoxy resin cured product The rubber state elastic modulus and storage modulus at 40°C in the dynamic viscoelasticity evaluation of the epoxy resin cured material obtained in (2) were measured in the DMA measurement method in the torsion mode according to ASTM D 5279, as follows. Using a viscoelasticity measuring device (ARES, TA instrument), DMA measurements were performed on a specimen 2.0 mm thick, 12.7 mm wide, and 50 mm long in the temperature range of 40-280°C under a torsional vibration frequency of 1.0 Hz and a temperature increase rate of 5.0°C/min. The rubber state elastic modulus and storage modulus at 40°C were read. The storage modulus at 140°C, which was the temperature range above the glass transition temperature where the storage modulus was flat, was used as the rubber state modulus. (4) Viscosity measurement of epoxy resin composition 2102131-000636 -26- Viscosities of the epoxy resin composition obtained in (1) at 60 °C and after held at 60 °C for 2 hours were measured using a dynamic viscoelasticity measuring device (ARES, manufactured by TA Instruments) equipped with parallel plates with diameters of 40 mm (top) and 50 mm (bottom), which was operated under the conditions of a parallel plate gap of 0.6 mm, an angular frequency of 10 rad/s, a strain of 10%, and a measurement temperature of 60 °C in accordance with ASTM D 4473- 95a. (5) DSC (Differential Scanning Calorimeter) measurement of epoxy resin composition The curing calorific value of the epoxy resin composition of the present invention was determined from the peak area of the curing exothermic curve obtained by heating approximately 3 μg of the epoxy resin composition from room temperature at a rate of 10°C/min using a differential scanning calorimeter (Discovery DSC2500, TA instrument) in accordance with ASTM D 3418-15. (6) Degradability test of epoxy resin cured product The degradability of the epoxy resin cured material was confirmed by the following method. A test piece of 2.0 mm thick, 10.0 mm wide, and 20 mm long was cut from the epoxy resin cured material obtained in (2), and immersed in 12 ml of a mixed solution of 25% acetic acid solution and N-methylpyrrolidone at a volume ratio of 2:1. When the epoxy resin cured material decomposes, the solubility is judged as "A" (good), and when the epoxy resin cured material does not decompose and solids remain in the solution, the solubility is judged as "B" (poor). (7) Preparation of carbon fiber reinforced composite material A carbon fiber textile substrate (Torayca^TM T400H-3K, fiber areal weight: 193 g/m²) was coated with 129 g/m² of the epoxy resin composition obtained in (2) to obtain prepreg with a resin content of 40wt%. This prepreg was cut into 10 cm square pieces, and the 4-ply laminated pieces were formed in an autoclave under 0.6 MPa pressure conditions and the aforementioned curing condition A or curing condition B above to obtain a fiber-reinforced composite material with a thickness of approximately 1 mm. (8) Re-shapeability test of carbon fiber reinforced composite material The re-shapeability of the fiber-reinforced composites was evaluated by the following method. A test piece of 1.0 mm thick, 12.7 mm wide, and 50 mm long was 2102131-000636 -27- cut from the fiber-reinforced composite material obtained in (7), and heated in an oven so that the temperature of the test piece reached 140°C. The test piece was then removed from the oven and deformed by twisting in the longitudinal direction. The specimen that could be easily deformed was judged to have re-shapeability “A” (good), and the specimen that was difficult to deform was judged to have re-shapeability “B” (poor). (9) Solvent resistance test of epoxy resin cured product The solvent resistance of the epoxy resin cured material was checked by the following method. A test piece 2.0 mm thick, 10.0 mm wide, and 20 mm long was cut from the epoxy resin cured material obtained in (2), and immersed in acetone. After 12 hours of holding at room temperature, the specimen was evaluated at two levels: Solvent resistance “A” (Good) when the epoxy resin cured material remained solid without decomposing, and solvent resistance “B” (Poor) when the epoxy resin cured material dissolved. <Working example 1> Epoxy resin compositions were obtained by the method described in (1) with the ratios listed in Table 1. At this time, (F1): ((number of moles of active hydrogen contained in component [B]) / number of moles of epoxy group of component [A]) =0.3, (F2): (number of moles of active hydrogen contained in component [C] / number of moles of epoxy group of component [A]) = 0.7, (F3): ((number of moles of active hydrogen contained in component [B] + number of moles of active hydrogen contained in component [C]) / number of moles of epoxy group of component [A]) =1.0. The storage modulus of the resin-cured material evaluated by the method (3) at 40°C was 1.2 GPa, which was sufficient to obtain sufficiently high stiffness when used as a fiber-reinforced composite material. The rubber state elastic modulus of the resin-cured material at 140°C was 0.7 MPa, which was sufficiently low. In addition, the reshapeability evaluated by the method (8) was A. The initial viscosity of the resin composition evaluated by the method (4) at 60°C was 27 Pa-s, which is suitable for the resin film and prepreg manufacturing process. The ratio of the initial viscosity to the initial viscosity after 2 hours of holding at 60°C was 1.4, indicating good stability. The heat generation value of curing of the resin composition evaluated by the method (5) was 115 J/g, which was low enough to obtain a cured product with uniform performance. The decomposability of the resin cured material evaluated by the method of (6) was “A”. The solvent resistance of the resin cured material evaluated by the method of (8) was “A”. <Working example 2-4, 6-9> 2102131-000636 -28- Working example 2-4, 6-9 were also evaluated in the same manner as working example 1, except that the ratios of the formulation and curing conditions were different, with the ratios listed in Table 1. As shown in Table 1, good degradability, re- shapeability, and solvent resistance were also obtained in working example 2-8. <Working example 5> Working example 5 was also evaluated in the same manner as working example 1, and the ratios are shown in Table 1. However, in working example 5, a total of 15 part of Amine 1 was blended, of which 9 part were blended as component D in a preliminary reaction with component A, and the remaining 6 part were blended unreacted. As shown in Table 1, good degradability, re-shapeability, and solvent resistance were obtained in working example 5. <Comparative example 1-3> Comparative example 1-3 was also evaluated in the same manner as working example 1, except that the ratios of the formulation were different, with the ratios listed in Table 1. In comparative example 1, the pre-reactant corresponding to component [D] is not used, and component [B1] is blended without being pre-reacted with component [A]. Also, the hardener of component [C] is not included. The rubber state elastic modulus of the resin cured material evaluated by the method (3) at 140°C was 7.2 MPa, and the re-shapeability was inferior to that of the working example. The initial viscosity of the resin composition evaluated by the method (4) at 60°C was 0.20 Pa-s. The viscosity was too low in the resin film and prepreg manufacturing process, and the resin did not retain its form at room temperature, resulting in significantly poor handling properties. The ratio to the initial viscosity after holding at 60°C for 2 hours was 320, and the viscosity changed significantly during the process, resulting in a non- uniform amount of resin per area in the resin film and prepreg, and the prepreg produced was unstable, as the reaction progressed gradually during storage at room temperature, resulting in sequential changes in handling properties. The prepared prepregs were unstable, as the reaction progressed gradually during storage at room temperature, resulting in sequential changes in handling. In comparative example 2, the amine compound corresponding to component [B] and the pre-reactant corresponding to component [D] are not used. All epoxy resins are cured with the curing agent corresponding to component [C], and the cured product has no cross-linking points. Therefore, the solvent resistance of the resin cured products evaluated by the method in (8) was poor at “B”. In addition, the resin cured material was brittle, and DMA measurement was impossible due to the difficulty of specimen processing. 2102131-000636 -29- In comparative example 3, the pre-reactant corresponding to component [D] is not used, and component [B] is blended without being pre-reacted with component [A]. The rubber state elastic modulus of the resin cured material evaluated by the method (3) at 140°C was 8.3 MPa, and the remolding property was inferior to that of the Example. Component [B1] was not blended, and the degradability of the resin cured material evaluated by the method (6) was “B”, which is poor.

2102131-000636 -30- Table 1 ³ ₀ ^E _C 0 0 0⁰ ₁ 0 0 0 0 ⁷ ₄ 0 0 0 0 0 0 0 A 0 0^. ₁ 0^. ₁ B B A 2^. ₁ 3^. ₈ A^/ A N ^/ 7 N ⁸ ₃ ² ₀ ^E 0 _C ⁰ ₁ 0 0 0 0 0 0 0 0 ³ ₈ 0 0 0 0 1 A 0 0 0^. ₁ A A B A^/ A N ^{/ 7} N₃ ^. 1 0 ^. ₁ 3⁴ ₂ ¹ ₀ ^E 0 _C ⁰ ₁ 0 0 0 0 0 ² ₃ 0 0 0 0 0 0 0 0 A 0 0 0^. ₁ A B A 1^. ₁ 2^. ₇ ⁰ ₂ ^. 0 2 0 ² ₃ ¹ ₄9⁰ _E 0⁰ 0 0 9 0 0 0 0 0 ⁹ ₂ 0 0 ⁶ ₁ 0 1 A 3^. ₀ 7^. 0^. ₁ A A A 2^. ₁ 9^{. 9} ₄ 1^. 2⁴ W_{1 0 0 1 1}8⁰ _E 0⁰ 0 0 9 0 0 0 0 0 ⁰ ₅ 0 0 0 4 1 A 3^. 7^. 0^. A A A 2^. ₁ 0^{. 5} ₃ 5^. 1³ W_{1 0 0 1 1 1 1}7⁰ _E 0⁰ 0 0 0 0 5 0 0 0 ⁸ 0 0 0 0 1 A 2^. 8^. 0^. A A A 0^. 8^. 2^. 1^. 1⁰ W_{1 6 0 0 1 1 0 2 1 2}6⁰ _E 0 ⁸ 3^. 7 0 1 0 0 1 2 W⁰ ₁ 0 0 0 6 0 0 0 0 ₅ 0 0 0 0 1 A ₀ ^. ₀ ^. ₁ A A A ^. ₁ ^. ₁ ^. ₉ ^. ₁ ² ₁5⁰ _E 0⁰ 0 0 9 0 0 6 0 ² 0 0 0 0 0 B 3^. 7^. 0^. 1^. 3^. 0^. 8^. 1 W_{1 4} 0 _{0 0 1} A A A _{1 2 8 4} ⁵ ₁4⁰ _E 0 0 0 ⁰ 0 0 0 0 ³ 0 0 0 B 3^. 7^. 0^. 0^. 5^. 2^. 2^. 4 W ⁰ _{1 1 6} 0 0 0 _{0 0 1} A A A _{1 0 1 1} ¹ ₂3⁰ _E 0⁰ 0 0 9 0 0 0 0 0 0 ⁷ 6 0 0 1 A 3^. 7^. 0^. A A 0^. 9^{. 3} 9^. 8⁷ W_{1 2 0 0 1} A _{1 0 3 1 1}2⁰ _E 0⁰ 0 0 9 0 0 0 0 0 ⁹ ₂ ⁶ ₁ 0 0 0 1 A 3^. ₀ 7^. ₀ 0^. ₁ A A A 1^. ₁ 1^. ₁ ⁵ ₂ 2^. ₁ 0³ W_{1 1}1⁰ _E ⁰ ₅ ⁰ ₅ 0 ⁰ ₁ 0 0 0 0 0 ³ ₃ ⁸ ₁ 0 0 0 1 A 3^. ₀ 7^. 0^. A A A 2^. 7^{. 7} ₂ 4^. 5¹ W _{0 1 1 0 1 1} n_i ^y _x ^o _t _d ⁿ ^{e f} _i ⁿ _i _d ^o P _{C °} _n ⁱ _{o d} _a ^t _p ^{e f} _o ^e _n ⁿ _{e p} g^e _f ^M _N ]^a _P ⁰ ₆ _n ^u _n o _o ⁱ ^r _{a p} _g ^t _n ^{u i} _a _o ^t _o ^{r o} ^{r s} _d ⁿ ] ^{M t} _a _{g n} ^o _d ^y _{h e} ^l _{o a} ^a _P [^{s s} _r 1 1 _e 2 e 3 e 1 e 5 e ¹ _l ² _l ³ _l ⁴ _l ¹ _c _l ^{n y} _x ^o _c _y 2 3 ^{n n y} _c ^d x ⁿ _e ^{v m} _i ^c _a ^G [ _u ^l _u ^u _o ^{h ]} ^x _y ^x _y ^x _i ⁿ m_i ⁿ m_i ⁿ m_i 4 ⁿ m_e ⁿ _i ^o _n ^o _n ^o _n ^o _n ^{o 1} _e ^{g o} _{p e} ^o _e ^g _i ^t _f m^e _h ^e _h ^e _h ^e _i _h ^{h a} _o ^{r e} _f ^g _{o p} ^e _o ^r _c ^{a o} _{r ci} ^C ^t _° ^d C _{0 o} ^{] 2} _g ^/ ^m _s- _r ^e _J[ _o ^p _o _E ^p _o _E ^p _E ^A] ₁ ^A] ^B ₁ ^A] ₁ ^A _i ]₁ ^m _A ^A] ₁ ^P] [ ^B _[ ^B _[ ^B _[ ^C _{[ 2} ^P] ^C ₂ ^P] ₂ ^P] _T ₂ ^] _e ₃ ^r _d ^{y o r} _{d f d} ^y _f ^{o e} _{b e} ^{c 0} [ ^C _[ ^C _[ ^C _[ ^C _U _{[ h} _e ^s ₄ ⁴ _t ^ci _a ^P _{tf e} v _e ^y _h ^os _h ^{s m} _a ^{f 1 a u} ^s _t ^s _[ C^a _l ^a i ^l ^t _{o e e} ^l _e n _c ^v _e ^l _u ⁿ _{o t} _n ^a _u ^l _a ^{l °} _y ^ti _{y vc} _o ^{a m} _f ^v _i ^t _{o i} _c ^{m t} _{c o} a^m _/ ⁾ ⁱ _] ^oi _t ^d _e ^t e _{u e 0} n^d _e ^{t 6} _s t^o _{c ti} ^s _i ^fi _r t _f _i ^{o o} _r ^a _{f f} ^o ^d _{r f f} o^o _r ^C [ ^u ⁾ _l ^o _a ^e _{h o} ^t _o m _a ^t _{s a} ^s ^y _{i o} t ^{v c} _s ^o ⁱ _l ^a n ^s ^o _e ^e c ^l _b ^o o ^{m s} _e ^e ^l _b ^s _e ^{l e} _b ^t _n ^e _] ^A _s [ ^{d e} _{r e} ^c _{a e} ^g _a ^r _{e i} ^s _f _o ^o _v ^l _c _{a g} ⁿ ^m _u ⁿ _o ^m _{u o} m^m _{u n} ^{o t} _{n e} ^x _{i n} ^{e o} _t ^r _o ^b ^t _b ^{u c} _s ^o ^{i i} _t ⁱ ^a t_i i n _r ^u ]^A ] ^e _r ^u _f ^o _/ ^m [ ^B _{r )]} ⁾ _{] f} ⁿ ^{o /} _f ⁿ _p ^e ] ^o _r ⁺ _] m^o _n ^{o m} _h n _i w _e _y ^c _{n S R V R i C} a ^t _{[ C} ^{e B} _[ ^A _{[ r} ^C _[ ^{e B} _{[ c p} _n ^t ^e _{n b} ^{t t e} _b ^t _b ^{t n} _i m ^y _t ^t ⁱ i _t l _l ^{i s} _i ^{s y} _t _n ^e ^o _n ^m _n _p ^o _p ] _u B ] ^{n e} _n _n ^e _n m_n ^m ^{u e} _n _{n u} ^{n e} _{n d} ^o ^e _c ^f _i ^b _b _a ^a _{e e} ^r A _i _t ^{M s} _o C c^S [ ^C ] [ ^E _{[ (} ⁽ _: ^o _p ^o _{p n} ⁽ _: ^o _{p (} ⁽ _: ^o _{p n} ⁱ _{a o} ^{d p} ^t _{p a} ^r _a ^{h n} _{e D s} ⁱ _D m^o m ^{t t t )} C ^o _{C n} ^e _n ^e _n ^e ₁ ^F mm ⁾ ( ^o _c ^o ₂ ^F m ⁾ ^o ₃ ^F m^o _n ^u ^o _o ^r _g ^e _s ^{e v} _l ^o _V ] _{n n c ( c ( c c g D R S} D [ ^o _n t _p ^o _p ^o _{p n} ⁿ n m e^o m^o m^{o o} _i ^t _n ⁱ n_{C C C} ⁱ _s ^{y i} s_{t s} ^e _r ^y _t o^{o o}i_t ^e _r ^r _{e d} ^r _e _{p p} ^a _d ^{p e p} m _r ^e _{r o} ^r _r ^u _o ^r m^{o o u} _{p c p} _{C C C} ⁿ _U

Claims

2102131-000636 -31- What is claimed is: 1. A curable epoxy resin composition containing the following components [A], [B] and [C], wherein the curable epoxy resin composition comprises the reaction product of components [A] and [B] as component [D], and wherein the curable epoxy resin composition comprises the following component [B1] as component [B] included in component [D]; [A]: at least one epoxy resin; [B]: at least one amine compound; [C]: at least one curing agent other than component [B]; [B1]: at least one amine compound containing the structure represented by following formula (I) or (II) in a molecule: (I) (II) . 2. claim 1, wherein when the curable epoxy resin composition is cured, the rubber state modulus of the cured material by DMA (dynamic mechanical analysis) is 5.0 MPa or less. 3. The curable epoxy resin composition according to claim 1, having a viscosity at 60°C of 1.0 Pa-s or more. 4. The curable epoxy resin composition according to claim 1, having a curing calorific value of 240 J/g or less measured by differential scanning calorimetry (DSC) at a heating rate of 10 ° C/min. 5. The curable epoxy resin composition according to claim 1, wherein a blending ratio of the components [A] and [B] in component [D] satisfies (F1): (F1): ((the number of moles of active hydrogens contained in component [B]) / the number of moles of epoxy groups of component [A]) ≦ 0.4. 6. The curable epoxy resin composition according to claim 1, comprising component [C1] as the component [C], wherein [C1] is at least one aromatic amine compound. 7. The curable epoxy resin composition according to claim 1, comprising component [C2] as the component [C] , wherein [C2] is at least one phenol compound. 8. The curable epoxy resin composition according to claim 1, comprising component [C3] as component [C], wherein [C3] is at least one thiol compound. 2102131-000636 -32- 9. The curable epoxy resin composition according to claim 1, comprising component [C1] as the component [C], wherein [C1] is at least one aromatic amine compound having 2 active hydrogen atoms in the molecule. 10. The curable epoxy resin composition according to claim 1, comprising component [C2] as the component [C], wherein [C2] is at least one phenol compound having 2 active hydrogen atoms in the molecule. 11. The curable epoxy resin composition according to claim 1, comprising component [C3] as component [C], wherein [C3] is at least one thiol compound having 2 active hydrogen atoms in the molecule. 12. The curable epoxy resin composition according to claim 1, wherein a blending ratio of components [C] and [A] satisfies (F2): (F2): 0.5 ≦ (the number of moles of active hydrogens contained in component [C] / the number of moles of epoxy groups of component [A]). 13. The curable epoxy resin composition according to claim 1, wherein a blending ratio of components [A], [B] and [C] satisfies (F3): (F3): 0.8 ≦ ((the number of moles of active hydrogens contained in component [B] + the number of moles of active hydrogens contained in component [C]) / the number of moles of epoxy groups of component [A]) ≦ 1.2. 14. The curable epoxy resin composition according to claim 1, wherein component [C] is a curing agent having 2 active hydrogen atoms in the molecule. 15. The curable epoxy resin composition according to claim 1, wherein component [A] is a bifunctional epoxy resin. 16. The curable epoxy resin composition according to claim 1, further comprising component [E]: [E] at least one catalyst. 17. The curable epoxy resin composition according to claim 16, wherein the component [E] is at least one catalyst selected from the group consisting of an aromatic urea compound, an imidazole derivative and a phosphorus compound. 18. A cured epoxy resin composition formed from a curable epoxy resin composition containing the following components [A], [B] and [C], wherein the curable epoxy resin composition comprises the reaction product of components [A] and [B] as component [D], and wherein the curable epoxy resin composition comprises the following component [B1] as component [B] included in component [D]; [A]: at least one epoxy resin; [B]: at least one amine compound; [C]: at least one curing agent other than component [B]; 2102131-000636 -33- [B1]: at least one amine compound containing the structure represented by following formula (I) or (II) in a molecule: (_I) ^(II) wherein a ratio of composition to a rubber state modulus at 40°C [Pa]/rubber state modulus [Pa]) in a dynamic viscoelasticity evaluation is 180 or more. 19. The cured epoxy resin composition according to claim 18, the ratio of the storage modulus at 40°C of the cured epoxy resin composition to the rubber state modulus of the cured epoxy resin composition (storage modulus at 40°C [Pa]/rubber state modulus [Pa]) in a dynamic viscoelasticity evaluation being 200 or more. 20. The cured epoxy resin composition according to claim 18, the ratio of the storage modulus at 40°C of the cured epoxy resin composition to the rubber state modulus of the cured epoxy resin composition (storage modulus at 40°C [Pa]/rubber state modulus [Pa]) in a dynamic viscoelasticity evaluation being 400 or more. 21. The cured epoxy resin composition according to claim 18, the ratio of the storage modulus at 40°C of the cured epoxy resin composition to the rubber state modulus of the cured epoxy resin composition (storage modulus at 40°C [Pa]/rubber state modulus [Pa]) in a dynamic viscoelasticity evaluation being 600 or more. 22. The cured epoxy resin composition according to claim 18, the ratio of the storage modulus at 40°C of the cured epoxy resin composition to the rubber state modulus of the cured epoxy resin composition (storage modulus at 40°C [Pa]/rubber state modulus [Pa]) in a dynamic viscoelasticity evaluation being 800 or more. 23. The cured epoxy resin composition according to claim 18, the ratio of the storage modulus at 40°C of the cured epoxy resin composition to the rubber state modulus of the cured epoxy resin composition (storage modulus at 40°C [Pa]/rubber state modulus [Pa]) in a dynamic viscoelasticity evaluation being 1000 or more. 24. The cured epoxy resin composition according to claim 18, the ratio of the storage modulus at 40°C of the cured epoxy resin composition to the rubber state modulus of the cured epoxy resin composition (storage modulus at 40°C [Pa]/rubber state modulus [Pa]) in a dynamic viscoelasticity evaluation being 1500 or more. 25. A curable epoxy resin composition containing the following components [A], [B] and [C], wherein the curable epoxy resin composition comprises the reaction product of components [A] and [B] as component [D], and wherein the curable epoxy 2102131-000636 -34- resin composition comprises the following component [B1] as component [B] included in component [D]; [A]: at least one epoxy resin; [B]: at least one amine compound; [C]: at least one curing agent other than component [B]; [B1]: at least one amine compound containing the structure represented by following formula (I) or (II) in a molecule: (I) (II) wherein the holding at 60°C for 2 hours is 5 times or an epoxy resin composition at 60°C. 26. The curable epoxy resin composition according to claim 25, wherein the viscosity of the curable epoxy resin composition after holding at 60°C for 2 hours is 4 times or less than an initial viscosity of the curable epoxy resin composition at 60°C. 27. The curable epoxy resin composition according to claim 25, wherein the viscosity of the curable epoxy resin composition after holding at 60°C for 2 hours is 3 times or less than an initial viscosity of the curable epoxy resin composition at 60°C. 28. The curable epoxy resin composition according to claim 25, wherein the viscosity of the curable epoxy resin composition after holding at 60°C for 2 hours is 2 times or less than an initial viscosity of the curable epoxy resin composition at 60°C. 29. The curable epoxy resin composition according to claim 25, wherein the viscosity of the curable epoxy resin composition after holding at 60°C for 2 hours is 1.5 times or less than an initial viscosity of the curable epoxy resin composition at 60°C. 30. The curable epoxy resin composition according to claim 25, wherein the viscosity of the curable epoxy resin composition after holding at 60°C for 2 hours is 1.2 times or less than an initial viscosity of the curable epoxy resin composition at 60°C. 31. A curable epoxy resin composition containing the following components [A], [B] and [C], wherein the curable epoxy resin composition comprises the reaction product of components [A] and [B] as component [D], and wherein when cured, the epoxy resin has a rubber state elastic modulus obtained by DMA (dynamic mechanical analysis) of 5.0 MPa or less; [A]: at least one epoxy resin; 2102131-000636 -35- [B]: at least one amine compound; [C]: at least one curing agent other than component [B]. 32. A curable epoxy resin composition containing the following components [A], [B] and [C], wherein the curable epoxy resin composition comprises the reaction product of components [A] and [B] as component [D], having a curing calorific value of 240J/g or less as measured by differential scanning calorimetry (DSC) at a heating rate of 10° C / min; [A]: at least one epoxy resin; [B]: at least one amine compound; [C]: at least one curing agent other than component [B]. 33. A curable epoxy resin composition containing the following components [A], [B] and [C], and wherein the curable epoxy resin composition comprises the following component [B1] as component [B], wherein a blending ratio of components [C] and [A] satisfies (F2): (F2): 0.5 ≦ (the number of moles of active hydrogens contained in component [C] / the number of moles of epoxy groups of component [A]); [A]: at least one epoxy resin; [B]: at least one amine compound; [C]: at least one curing agent other than component [B]; [B1]: at least one amine compound containing the structure represented by following formula (I) or (II) in a molecule. 34. The curable epoxy resin composition according to claim 33, comprising component [C1] as the component [C], wherein [C1] is at least one aromatic amine compound having 2 active hydrogen atoms in the molecule. 35. The curable epoxy resin composition according to claim 33, comprising component [C2] as the component [C], wherein [C2] is at least one phenol compound having 2 active hydrogen atoms in the molecule. 36. The curable epoxy resin composition according to claim 33, comprising component [C3] as component [C], wherein [C3] is at least one thiol compound having 2 active hydrogen atoms in the molecule. 37. A cured epoxy resin composition formed from the curable epoxy resin composition according to any one of claims 1 to 36. 38. A resin film comprising the cured epoxy resin composition according to claim 37. 39. A fiber-reinforced composite material comprising the cured epoxy resin according to claim 37 and a reinforcing fiber. 2102131-000636 -36- 40. An adhesive resin film comprising the curable epoxy resin composition according to any one of claims 1 to 36. 41. A prepreg comprising reinforcing fiber bundles impregnated with the curable epoxy resin composition according to any one of claims 1 to 36. 42. A fiber-reinforced composite material obtained by curing the prepreg according to claim 41. 43. A prepreg comprising reinforcing fiber bundles impregnated with the curable epoxy resin composition according to any one of claims 1 to 36, wherein the prepreg contains unidirectionally oriented discontinuous carbon fibers. 44. A fiber-reinforced composite material obtained by curing the prepreg according to claim 43. 45. A process for recycling a product comprising a cured epoxy resin composition and a fiber-reinforced composite material, wherein the process includes immersing the product in an acidic solvent at a temperature in the range of 25 to 200°C under conditions sufficient to remove the cured epoxy resin composition from the product, wherein the cured epoxy resin composition is formed from a curable epoxy resin comprising the following components [A], [B] and [C], wherein the resin composition comprises the reaction product of components [A] and [B] as component [D], and wherein the curable epoxy resin composition comprises the following component [B1] as component [B] included in component [D]; [A]: at least one epoxy resin; [B]: at least one amine compound; [C]: at least one curing agent other than component [B]; [B1]: at least one amine compound containing the structure represented by following formula (I) or (II) in a molecule: (_I) ^(II) . 46. solvent of an acid and an organic solvent is used. 47. A resin decomposition product obtained by the process according to claim 45 or claim 46. 48. The fiber material recovered from fiber-reinforced epoxy resin composites decomposed by the method according to claim 45 or claim 46. 2102131-000636 -37- 49. A process for recycling a product comprising a cured epoxy resin composition and a fiber- reinforced composite material, wherein the process includes immersing the product in an acidic solvent at a temperature in the range of 25 to 200°C under conditions sufficient to remove the cured epoxy resin composition from the product, wherein the cured epoxy resin composition is formed from a curable epoxy resin comprising the following components [A], [B] and [C], wherein the curable epoxy resin composition comprises the following component [B1] as component [B], and wherein a blending ratio of components [C] and [A] satisfies (F2): (F2): 0.5 ≦ (the number of moles of active hydrogens contained in component [C] / the number of moles of epoxy groups of component [A]); [A]: at least one epoxy resin; [B]: at least one amine compound; [C]: at least one curing agent other than component [B]; [B1]: at least one amine compound containing the structure represented by following formula (I) or (II) in a molecule: . 50. The process according to claim 49, wherein a mixed solvent of an acid and an organic solvent is used. 51. A resin decomposition product obtained by the process according to claim 49 or claim 50. 52. The fiber material recovered from fiber-reinforced epoxy resin composites decomposed by the method according to claim 49 or claim 50. 2102131-000636 -38- 53. A process for recycling a product comprising a cured epoxy resin composition and a fiber-reinforced composite material according to any one of claims 39, 42 and 44, wherein the process includes immersing the product in an acidic solvent at a temperature in the range of 25 to 200°C under conditions sufficient to remove the cured epoxy resin composition from the product. 54. The process according to claim 53, wherein a mixed solvent of an acid and an organic solvent is used. 55. A resin decomposition product obtained by the process according to claim 53. 56. The fiber material recovered from fiber-reinforced epoxy resin composites decomposed by the method according to claim 53. 57. The curable epoxy resin composition according to claim 1, wherein the rubber state modulus of the cured material by DMA (dynamic mechanical analysis) is 5.0 MPa or less when the curable epoxy resin composition is cured at 135°C for 2 hours.

2102131-000636 -39- Abstract A curable epoxy resin composition is described that comprises the following components [A], [B] and [C], wherein the resin composition comprises the reaction product of components [A] and [B] as component [D], and optionally comprises the component [B1] as component [B] included in component [D]; [A]: at least one epoxy resin; [B]: at least one amine compound; [C]: at least one curing agent other than component [B]; [B1]: at least one amine compound containing the structure represented by following formula (I) or (II) in a molecule (_I) ^(II) wherein the epoxy resin composition as cured has a viscosity suitable for handling, excellent reaction stability, and excellent re-shapeability and easy degradation after curing, which can be used for resin films, fiber-reinforced composite materials, prepregs formed by impregnating the curable epoxy resin composition into reinforcing fibers, and fiber-reinforced composite materials containing the curable epoxy resin composition and reinforcing fibers. Also described is a process for recycling a product comprising the epoxy resin composition as cured and a fiber-reinforced composite material, wherein the process includes immersing the product in an acidic solvent at a temperature in the range of 25 to 200°C under conditions to remove the cured epoxy resin from the product. 4914-1612-2664, v. 1