Graphene-toughened cycloaliphatic epoxy resin composition

Abstract

The present disclosure relates to a curable composition comprising a cycloaliphatic epoxide; a curing agent; and graphene, and a method of producing or using the same.

Description

GRAPHENE-TOUGHENED CYCLOALIPHATIC EPOXY RESIN COMPOSITIONFIELD

[0001] The present disclosure relates to a curable epoxy composition capable of forming a cured product and methods of use thereof.BACKGROUND

[0002] Epoxy resins have been used as a resin to cover such as an optical semiconductor element in an optical semiconductor apparatus, a resin for molded products such as an ignition coil, a resin for a fiber-reinforced resin, a resin for a rotary electric machine and the like

[0003] The curable resin materials are exemplified by epoxides that excel typically in electrical properties, water- vapor resistance, and heat resistance. Among them, cycloaliphatic epoxides are materials excellent typically in electrical properties, water-vapor resistance, heat resistance, transparency, and curability and are suitable particularly in molding of wafer-level lenses. A cycloaliphatic epoxide is used so as to give a cured product having a higher glass transition temperature.

[0004] Various attempts have been made to allow cured products of curable compositions including a cycloaliphatic epoxide to have still higher glass transition temperatures and / or still higher mechanical strength. All the prior disclosures, however, fail to disclose a way to allow a material to maintain its high curability and to still give a cured product having higher mechanical strength and still having a high glass transition temperature as maintained. In addition, all the citations fail to describe a way to efficiently give a high-quality wafer-level lens as mentioned above.SUMMARYTechnical Problem

[0005] A resin having excellent heat resistance even in a high temperature environment has been desired. However, the resins formed from the resin compositions may not have satisfied sufficient heat resistance.

[0006] Therefore, the present disclosure relates to a curable composition capable of forming a cured product having excellent heat resistance even in a high temperature environment.Solution to Problem

[0007] As a result of intensive studies to achieve the above object, the inventor of the present disclosure has found that a cured product having excellent heat resistance can be formed even in a high temperature environment using a curable composition including an alicyclic compound having an alicyclic structure in a molecule, an acid anhydride-based curing agent, and graphene. The present disclosure relates to embodiments completed based on these findings.

[0008] The present disclosure provides a curable composition including a cycloaliphatic epoxide (A) having an alicyclic structure and an epoxy group in a molecule, a curing agent (B), and graphene as a toughening agent (C).

[0009] The present disclosure also provides a curable composition for any cured products including a rotary electric machine, including a cycloaliphatic epoxide (A) having an alicyclic structure and an epoxy group in a molecule, a curing agent (B), and graphene as a toughening agent (C), and may be liquid at 25 °C.

[0010] The curable composition may further include a chain extender (D).

[0011] The curable epoxy composition may further include a catalyst (E).

[0012] The curable composition may include one or more antioxidants selected from the group consisting of phenol-based antioxidants, hindered amine-based antioxidants, phosphorous-based antioxidants, and sulfur-based antioxidants.

[0013] The curable composition may include one or more poly hydric alcohols selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, and glycerin.

[0014] The present disclosure also provides a molded article formed from the cured product of the curable composition.Advantageous Effects

[0015] According to the curable composition of the present disclosure, a cured product can be formed that has excellent mechanical properties and toughness while maintaining high heat resistance even in a high temperature environment. Therefore, when the curable composition is used for example in a rotary electric machine (especially a rotary electric machine for an automobile), the rotary electric machine can operate properly even at a high operating environment temperature.

[0016] The curable composition according to the present embodiment, as having the configuration, can be cured satisfactorily and still can give a cured product that has a high glass transition temperature as maintained and exhibits high mechanical strength and toughness while maintaining high heat resistance. The cured product may excel in properties such as heat resistance, transparency, and water-vapor resistance. The curable composition is therefore preferably usable as a composition for optical element formation.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles.

[0018] Figure 1 is a photograph showing an appearance of the cured product prepared in Example 1.

[0019] Figure 2 illustrates a graph of storage modulus (MPa) of the cured product prepared in Example 1.

[0020] Figure 3 illustrates a graph of a thermomechanical analysis (TMA) of the cured product prepared in Example 1.

[0021] Figure 4 illustrates a graph of a thermogravimetric analysis (TGA) of the cured product prepared in Example 1.

[0022] Figure 5 illustrates a graph of a water absorption of the cured product prepared in Example 1.

[0023] Figure 6 illustrates a graph of reactivity and viscosity of the cured product prepared in Example 1.

[0024] Figure 7 illustrates results of the cured product prepared in Example 2.DETAILED DESCRIPTION

[0025] Hereinafter, the present disclosure will be described in more detail to help the understanding of the present disclosure.

[0026] As used herein and unless otherwise indicated, “% by weight” and “wt %” refer to a weight percent based on a total weight of a reference unless otherwise explained.

[0027] When the term “about” is used, it is used to mean a certain effect or result can be obtained within a certain tolerance, and the skilled person knows how to obtain the tolerance. When the term “about” is used in describing a value or an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to. In one aspect, the term “about” means plus or minus 20% of the numerical value of the number with which it is being used.

[0028] As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0029] The transitional phrase “consisting of’ excludes any element, step, or ingredient not specified in the claim, closing the claim to the inclusion of materials other than those recited except for impurities ordinarily associated therewith. When the phrase “consists of’ appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole.

[0030] The transitional phrase “consisting essentially of’ limits the scope of a claim to the specified materials or steps and those that do not materially affect the basic and novel characteristic(s) of the claimed embodiment. A “consisting essentially of’ claim occupies a middle ground between closed claims that are written in a “consisting of’ format and fully open claims that are drafted in a “comprising” format. Optional additives as defined herein, at a level that is appropriate for such additives, and minor impurities are not excluded from a composition by the term “consisting essentially of.”

[0031] Further, unless expressly stated to the contrary, “or” and “and / or” refers to an inclusive and not to an exclusive. For example, a condition A or B, or A and / or B, is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0032] The use of “a” or “an” to describe the various elements and components herein is merely for convenience and to give a general sense of the disclosure. This description should beread to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

[0033] The term “composition for optical element formation” refers to a material for the formation of a variety of optical elements and optical devices.

[0034] As used herein the term “wafer-level lens” refers to a lens for use in the wafer-level production of a camera to be used typically in a mobile phone. The “wafer-level lens” may have a size in diameter of typically from about 1 to about 10 mm, and preferably from about 3 to about 5 mm and a thickness of typically from about 100 to about 1500 pm, and preferably from about 500 to about 800 pm.

[0035] In one aspect, the present disclosure relates to a curable composition. In some embodiments, the curable composition comprises a cycloaliphatic epoxide.Curable Composition

[0036] The curable composition according to some embodiments of the present disclosure may include a cycloaliphatic epoxide (A), a curing agent (B), and graphene (C). The curable composition according to some embodiments of the present disclosure may include a cycloaliphatic epoxide (A), a curing agent (B), graphene (C) and silicone. In some embodiments, the curable composition may be thermosetting.

[0037] As used herein, the term “curable” means that the composition one or more curable functional groups capable of forming covalent bonds, polymerized or crosslinked. As used herein, the term “thermosetting” refers to resins that “set” irreversibly upon curing or crosslinking, wherein the polymer chains of the polymeric components are joined together by covalent bonds. In some embodiments, a curable composition of the present disclosure may include at least one curable compound. In some embodiments, the curable compound may be a compound having a curable group and may be any chemical forms, for example, a monomer, prepolymer, an oligomer, or mixture thereof.

[0038] As used herein, the product obtained by curing a curable composition is referred to as the cured product or cured article of the curable composition. The curing process may be induced by a curing agent, heat and / or energy. The curable composition may be cured by heat that solidified the curable composition. Forms of energy may include radiation such as electromagnetic radiation and thermal energy. Suitable wavelengths may include wavelengths inthe infrared, visible, or ultraviolet portion of the electromagnetic spectrum. The radiation curing reaction may occur in the presence of a photoinitiator. A radiation-curable component may also be thermally curable. Similarly, a curable composition may be a thermally curable composition that can be induced to undergo a curing reaction when exposed to thermal energy of sufficient intensity for a sufficient period of time. A thermally curable component may also be radiation curable.

[0039] The curable composition may be liquid at 25° C. The curable composition being liquid at 25° C may be excellent in workability such as an impregnation property and a casting property. The viscosity of the curable composition at 25° C may not be particularly limited, but may be about 330 mPa s or greater, for example, from about 330 to about 100,000 mPa s. If the viscosity is 330 mPa s or greater, the composition may not drip off after impregnation, and the workability during impregnation and casting may tend to improve. If the viscosity is 100000 mPa s or less, the impregnation property and the workability during casting may tend to improve, and a defect due to poor casting may be less likely to occur in the cured product. The viscosity of the curable composition at 25° C may be measured, for example, using a digital viscometer (model No. “DVU-EII”, available from TOKIMEC INC.) under conditions: rotor: standard 1° 34'xR24; temperature: 25° C; rotation speed: from 0.5 to 10 rpm.

[0040] In some aspects of the curable composition, the viscosity of the curable composition at 25° C may be 400 mPa s or greater, for example, from 400 to 10000 mPa s, or 450 mPa s or greater, for example, from 450 to 1000 mPa s. In another aspect of the curable composition, for example, in a case where the inorganic filler (E) is included, the viscosity of the curable composition at 25° C may be 2000 mPa s or greater, for example, from 2000 to 100000, 8000 mPa s or greater, for example, from 8000 to 80000 mPa s, or 10000 mPa s or greater, for example, from 10000 to 70000 mPa s. In some embodiments, the viscosity of the curable composition may be about 300, 400, 500, 600, 700, 800, 900, 1,000, 2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000, 10,000, 20,000, 30,000, 40,000, 50,000, 60,000, 70,000, 80,000, 90,000 mPa s or greater and / or about 100,000, 90,000, 80,000, 70,000, 60,000, 50,000, 40,000, 30,000, 20,000, 10,000, 9,000, 8,000, 7,000, 6,000, 5,000, 4,000, 3,000, 2,000, 1,000, 900, 800, 700, 600, 500, 400, mPa s or less.

[0041] Some embodiments of the curable composition may be, for example, a curable composition for a rotary electric machine, including a cycloaliphatic epoxide (A), an a curingagent (B), and graphene (C) and may be liquid at 25° C. Because the curable composition is liquid at 25° C, the curable composition may be excellent in an impregnation property and a casting property and thus excellent in workability, and a cured product obtained by curing the curable composition may have a high glass transition temperature and maintaining excellent high heat resistance. Another embodiments of the curable composition may include, for example, a curable composition for a rotary electric machine, including a cycloaliphatic epoxide (A), a curing agent (B), and graphene (C), and may further include a chain extender (D) a catalyst (E), and / or silica (F) and / or dispersing agent (G). The cured product obtained by curing the curable composition may have a high glass transition temperature, excellent flexibility, and bending strain that is further improved. The curable composition may further include a chain extender. Furthermore, the curable composition may further include a catalyst.Cycloaliphatic Epoxide (A)

[0042] The cycloaliphatic epoxide (A) may be a compound having one or more alicyclic rings and one or more epoxy groups in the molecule. As used herein, the term “cycloaliphatic” refers to a saturated or partially unsaturated aliphatic monocyclic, bicyclic, or polycyclic ring system having, for example, 3 to 30 members, wherein the aliphatic ring system is optionally substituted. Examples of cycloaliphatic compounds may include cyclohexane, methylcyclohexane, cyclopentane, cyclohexene, piperidine, N-aminoethylpiperazine (AEP), and the various epoxy resins derived from cycloaliphatic alcohols like hydrogenated bisphenol-A diglycidyl ether. As used herein, the term “epoxide” refers to a substituted or unsubstituted oxirane or ethylene oxide. As used herein, the term “substitute” refers to replacing one or more of hydrogen in a corresponding group with a hydroxyl group, a nitro group, a cyano group, an amino group, a carboxyl group, a linear or branched Cl to C30 alkyl group, a Cl to CIO alkyl silyl group, a C3 to C30 cycloalkyl group, a C6 to C30 aryl group, a C2 to C30 heteroaryl group, a Cl to CIO alkoxy group, a halogen, or a Cl to CIO fluoro alkyl group.

[0043] The cycloaliphatic epoxide (A) may have two or more epoxy groups in the molecule. In some embodiments, the cycloaliphatic epoxide (A) may have 3, 4, 5, 6, 7, 8, 9 or 10 epoxy groups in the molecule. The curable composition may include at least one cycloaliphatic epoxide (A). In some embodiments, the curable composition may include two or morecycloaliphatic epoxides (A).

[0044] As the cycloaliphatic epoxide (A), a well-known or commonly used cycloaliphatic epoxide can be used. Examples of the cycloaliphatic epoxide (A) include, but are not particularly limited to, (I) a compound having an epoxy group (referred to as “alicyclic epoxy group”), which is a group constituted of two adjacent carbon atoms and an oxygen atom that constitute an alicyclic ring in the molecule; (II) a compound in which an epoxy group is directly bonded to an alicyclic ring through a single bond; and (III) a compound having an alicyclic ring and a glycidyl ether group in the molecule (a glycidyl ether type epoxy compound). In some embodiments, the cycloaliphatic epoxide (A) may include a compound having an epoxy group directly bonded to an alicyclic ring having C3 to Cl 2 carbon atoms. In some embodiment, the cycloaliphatic epoxide (A) may include a compound having an epoxy group directly bonded to an alicyclic ring having C3, C4, C5, C6, C7, C8, C9, CIO, Cl 1 or C12 carbon atoms. In some embodiments, the cycloaliphatic epoxide (A) may preferably include a compound having two or more alicyclic rings having C6 carbon atoms to which an epoxy group is directly bonded. In some embodiments, the cycloaliphatic epoxide (A) may preferably include a compound having two alicyclic rings having C6 carbon atoms to which an epoxy group is directly bonded

[0045] In some embodiments, the curable composition may include the cycloaliphatic epoxide (A) including a compound represented by Formula (I):Formula (I) wherein, in Formula (I), X is a single bond or a linkage group.

[0046] In Formula (I), X may represent a single bond or a linking group , and the linking group may comprise divalent group. As used herein, the term “linkage group” refers to a specific chemical bond or functional group that connects different parts of a molecule together, and the linkage group may include at least one selected from a carbon atom, nitrogen atom, sulfur atom, and oxygen atom. Examples of the linking group include a divalent hydrocarbon group, an epoxidized alkenylene group in which some or all of the carbon-carbon double bonds are epoxidized, a carbonyl group, an ether bond, an ester bond, a carbonate group, an amide group, and a linked group in which a plurality of the above groups are linked. Note that substituents such as alkyl groups may be bonded to one or more of the carbon atoms constituting the cyclohexane ring in Formula (I).

[0047] In some embodiments, the divalent group of the present disclosure may comprise at least one selected from the group consisting of: a divalent hydrocarbon group; an epoxidized alkenylene group in which some or all of the carbon-carbon double bonds are epoxidized; a carbonyl group; an ether bond; an ester bond; a carbonate group; an amido group; and combinations thereof.

[0048] In some embodiments, the divalent hydrocarbon group of the present disclosure may comprise a linear or branched alkylene group having from 1 to 18 carbon atoms or a divalent alicyclic hydrocarbon group. In some embodiments, the divalent hydrocarbon group of the present disclosure may comprise a linear or branched alkylene group having of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon atoms or a divalent alicyclic hydrocarbon group. In some embodiments, the linear or branched alkylene group having from 1 to 18 carbon atoms of the present disclosure may include a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, and a trimethylene group. In some embodiments, the divalent alicyclic hydrocarbon group of the present disclosure may include divalent cycloalkylene groups, including a cycloalkylidene group, such as a 1 ,2- cyclopentylene group, a 1,3-cyclopentylene group, a cyclopentylidene group, a 1,2- cyclohexylene group, a 1,3 -cyclohexylene group, a 1,4-cyclohexylene group, and a cyclohexylidene group.

[0049] In some embodiments, the alkenylene group in the epoxidized alkenylene group may include linear or branched alkenylene groups having from 2 to 8 carbons. In some embodiments, the alkenylene group in the epoxidized alkenylene group may include at least one selected from the group consisting of vinylene group, a propenylene group, a 1-butenylene group, a 2- butenylene group, a butadienylene group, a pentenylene group, a hexenylene group, a heptenylene group, and an octenylene group. In some embodiments, the epoxidized alkenylene group may include an epoxidized alkenylene group in which all of the carbon-carbon double bonds are epoxidized, an epoxidized alkenylene group having from 2 to 4 carbons in which all of the carbon-carbon double bonds are epoxidized.

[0050] In some embodiments, the linkage group of the present disclosure may include an oxygen. In some embodiments, the linkage group of the present disclosure may include at least one selected from the group consisting of — (CH2)X— (l<x<20), a cycloalkyl group having C3 to CIO alkyl such as cyclohexyl, — COO — CH2 — , — CO — , — O — CO — O — , — COO — , — O — ,— O — R — (R = Cl to C8 alkylene), — CONH — and combinations thereof.

[0051] In some embodiments, the cycloaliphatic epoxide (A) may comprise 3,4- epoxy cyclohexylmethyl 3 ’,4’ -epoxy cyclohexanecarboxylate represented by Formula (1-1) below:

[0052] In some embodiments, the cycloaliphatic epoxide compound represented by Formula (I) may include (3,4,3',4'-diepoxy)bicyclohexyl. In some embodiments, the cycloaliphatic epoxide compound represented by Formula (I) may include Celloxide 202 IP manufactured by Dai cel Corporation. In some embodiments, the cycloaliphatic epoxide represented by Formula (I) may include at least one selected from the group consisting of compounds represented by Formulae (I -1) to (I -10) below:).

[0053] In Formula (1-5) and (1-7), 1 and m each may represent an integer of 1 to 30. In some embodiments, in Formulae (1-5) and (1-7), 1 and m each may represent an integer from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 or 29 or more and / or 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3 or 2 or less. In some embodiments, R in Formula (1-5) may be an alkylene group havingfrom 1 to 8 carbons. In some embodiments, the alkylene group having from 1 to 8 carbons may include a linear or branched alkylene group having from 1 to 3 carbons, such as a methylene group, an ethylene group, a propylene group, or an isopropylene group. In Formulae (I -9) and (I -10), nl to n6 each may represent an integer from 1 to 30. In some embodiments, in Formulae (1-9) and (1-10), nl to n6 each may represent an integer from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 or 29 or more and / or 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3 or 2 or less. In addition, other examples of the cycloaliphatic epoxide represented by the formula (I) may include 2,2-bis(3,4-epoxycyclohexyl)propane, l,2-bis(3,4-epoxycyclohexan-l-yl)ethane, 1,2- epoxy-l,2-bis(3,4-epoxycyclohexan-l-yl)ethane, and bis(3,4-epoxycyclohexylmethyl)ether.

[0054] In some embodiments, the cycloaliphatic epoxide (A) may comprise a compound in which an epoxy group is directly bonded to an alicyclic ring through a single bond. In some embodiments, the cycloaliphatic epoxide (A) may include compounds represented by Formula (II).

[0055] In Formula (II), R" may include a group resulting from elimination of a quantity of p- hydroxyl groups ( — OH) from a structural formula of a p-hydric alcohol [R"(OH)X] wherein x is 1 to 10, and p and n each may represent an integer from 1 to 50. In some embodiments, in Formulae (II), p and n each may represent an integer from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48 or 59 or more and / or 50, 49, 48, 47, 46, 45, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3 or 2 or less. In some embodiments, p and n may be the same or different to each other. In some embodiments, in the p-hydric alcohol [R"(OH)X], x may represent an integer of 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10. In some embodiments, p may be from 1 to 6, and n may be from 1 to 30. In some embodiments, in Formula (II), R" may include Cl to Cl 5substituted or unsubstituted hydrocarbon group, such as Cl to 15 substituted or unsubstituted alkyl group, Cl to Cl 5 substituted or unsubstituted alkenyl group.

[0056] In some embodiments, in Formula (II), the p-hydric alcohol [R"(OH)X] may include at least one selected from the group consisting of polyhydric alcohols having Cl to Cl 5 carbon atoms and 2,2-bis(hydroxymethyl)-l -butanol. In some embodiments, in Formula (II), when p may be 2 or greater, n in each group in the outer parentheses may be the same or different. In some embodiments, the compound represented by Formula (II) may include a l,2-epoxy-4-(2- oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-l -butanol, such as a product of the trade name “EHPE3150™” (available from Daicel Corporation)).

[0057] In some embodiments, the cycloaliphatic epoxide (A) may include a compound (III) having an alicyclic ring and a glycidyl ether group in the molecule, which may be a glycidyl ether type epoxy compound. In some embodiments, the compound (III) having an alicyclic ring and a glycidyl ether group in the molecule may include glycidyl ethers of alicyclic alcohols, such as alicyclic polyhydric alcohols. In some embodiments, the compound (III) having an alicyclic ring and a glycidyl ether group in the molecule may include compounds obtained by hydrogenating a bisphenol A type epoxy compound (hydrogenated bisphenol A type epoxy compounds), such as 2,2-bis[4-(2,3-epoxypropoxy)cyclohexyl]propane and 2,2-bis[3,5-dimethyl- 4-(2,3-epoxypropoxy)cyclohexyl]propane; compounds obtained by hydrogenating a bisphenol F type epoxy compound (hydrogenated bisphenol F type epoxy compounds), such as bis[o,o-(2,3- epoxypropoxy)cyclohexyl]methane, bis[o,p-(2,3-epoxypropoxy)cyclohexyl]methane, bis[p,p- (2,3-epoxypropoxy)cyclohexyl]methane, and bis[3,5-dimethyl-4-(2,3- epoxypropoxy)cyclohexyl]methane; a hydrogenated bisphenol type epoxy compound; a hydrogenated phenol novolac type epoxy compound; a hydrogenated cresol novolac type epoxy compound; a hydrogenated cresol novolac type epoxy compound of bisphenol A; a hydrogenated naphthalene type epoxy compound; a hydrogenated epoxy compound of an epoxy compound obtained from trisphenolmethane; and a hydrogenated epoxy compound of an epoxy compound having another aromatic ring.

[0058] The proportion of the content of the cycloaliphatic epoxide (A) in the curable composition may be about 20 to about 70 % by weight, about 30 to about 60 % by weight, about 40 to about 50 % by weight with respect to the total amount (100 % by weight) of the curable composition.. In some embodiments, proportion of the content of the cycloaliphatic epoxide (A)in the curable composition may be about 20, 25, 30, 35, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 55, 60, 65 mass % or more, and / or about 70, 65, 60, 55, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 35, 30, 25 mass% or less with respect to the total amount (100 % by weight) of the curable composition.

[0059] In some embodiments, the proportion of the cycloaliphatic epoxide (A) in the epoxy compound content of the curable composition may be more than about 70, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 mass % or greater with respect to the total epoxy compound amount (100 mass %). In some embodiment, the proportion of the cycloaliphatic epoxide (A) in the epoxy compound content of the curable composition may be more than about 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99 mass % or greater and / or about 100, 99, 98, 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72 or 71 mass % or less with respect to the total epoxy compound amount (100 mass %).

[0060] In some embodiments, the content of each component (such as the cycloaliphatic epoxide (A) and the curing agent (B)) included in the curable composition can be appropriately selected from the range described, and thus each total content may be 100 mass % or less.

[0061] In some embodiments, the curable composition may comprise the cycloaliphatic epoxide (A) in an amount from about 5 to about 60 % by weight based on the total amount (100 % by weight) of the curable composition. In some embodiments, the curable composition may comprise the cycloaliphatic epoxide (A) in an amount from about 10 to about 55 % by weight based on the total amount (100 % by weight) of the curable composition. In some embodiments, the curable composition may comprise the cycloaliphatic epoxide (A) in an amount from about 15 to about 50 % by weight based on the total amount (100 % by weight) of the curable composition. In some embodiments, the curable composition may comprise the cycloaliphatic epoxide (A) in an amount from about 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 % by weight or more and / or about 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7 or 6 % by weight or less based on the total amount (100 % by weight) of the curable composition.Curing Agent (B)

[0062] The curing agent (B) may be a compound that has a function of curing the curable composition by reacting with a compound having an epoxy group such as the cycloaliphaticepoxide (A). The curable composition of the present disclosure may include a single type of curing agent (B), or may include two or more curing agent (B).

[0063] In some embodiments, the curing agent (B) may include an acid-anhydride-based curing agent. As the acid anhydride-based curing agent, a well-known or commonly used acid anhydride-based curing agent can be used. In some embodiments, the acid anhydride-based curing agent (B) may preferably include an acid anhydride having an alicyclic ring having C3 to C12 carbon atoms. In some embodiments, the acid anhydride-based curing agent (B) may preferably include an acid anhydride having an alicyclic ring having C6 carbon atoms. In some embodiments, the acid anhydride-based curing agent (B) may include, but are not particularly limited to, at least one selected from the group consisting of methyltetrahydrophthalic anhydrides (such as 4-methyltetrahydrophthalic anhydride and 3 -methyltetrahydrophthalic anhydride), methylhexahydrophthalic anhydrides (such as 4-methylhexahydrophthalic anhydride and 3- methylhexahydrophthalic anhydride), dodecenyl succinic anhydride, methyl endomethylene tetrahydrophthalic anhydride, phthalic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylcyclohexene dicarboxylic anhydride, pyromellitic anhydride, trimellitic anhydride, benzophenone tetracarboxylic anhydride, nadic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, 4-(4-methyl-3- pentenyl)tetrahydrophthalic anhydride, succinic anhydride, adipic anhydride, sebacic anhydride, dodecanedioic anhydride, methylcylohexene tetracarboxylic anhydride, vinyl ether-maleic anhydride copolymers, alkyl styrene-maleic anhydride copolymers, and combinations thereof. In some embodiments, the methyltetrahydrophthalic anhydrides may preferably comprise 4- methyltetrahydrophthalic anhydride and / or 3 -methyltetrahydrophthalic anhydride. In some embodiments, the methylhexahydrophthalic anhydrides may comprise 4- methylhexahydrophthalic anhydride and / or 3 -methylhexahydrophthalic anhydride. In some embodiments, the acid anhydride-based curing agent (B) may preferably include 4- methylhexahydrophthalic anhydride and hexahydrophthalic anhydride. In some embodiments, the curing agent may comprises a methyl nadic anhydride.

[0064] In some embodiments, the curing agent (B) may include an acid anhydride that is liquid at 25 °C, such as methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, dodecenyl succinic anhydride, or methyl endomethylene tetrahydrophthalic anhydride, from the viewpoint of handleability. Meanwhile, acid anhydrides that are solid at 25 °C may tend toimprove in handleability as a curing agent in the curable composition when, for example, dissolved in an acid anhydride that is liquid at 25 °C to form a liquid mixture. Thus, in some embodiment, the curing agent (B) may include an acid anhydride that is solid at 25 °C.

[0065] Furthermore, the curing agent (B) may include nadic anhydride or its derivative, such as nadic anhydride, methylnadic anhydride, or hydrogenated methylnadic anhydride. In some embodiments, the curing agent (B) may include methylnadic anhydride, from the viewpoint of further increasing the glass transition temperature of the cured product to further improve the heat resistance of the cured product.

[0066] In some embodiments, the curable composition may comprise the curing agent (B) in an amount from about 50 to about 200 % by weight, or from about 80 to about 150 % by weight with respect to 100 % by weight of the total amount of the cycloaliphatic epoxide (A). In some embodiments, the curable composition may comprise the curing agent (B) in an amount of about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190 % by weight or more, and / or about 200, 195, 190, 185, 180, 175, 170, 165, 160, 155, 150, 145, 140, 135, 130, 125, 120, 115, 110, 105, 100, 95, 90, 85, 80, 75, 70, 65, 60 % by weight or less with respect to 100 % by weight of the cycloaliphatic epoxide (A) included in the curable composition.

[0067] In some embodiments, the curable composition may comprise the curing agent (B) in a proportion of from about 0.5 to about 1.5 equivalents, from about 0.8 to about 1.1 equivalents, or about 0.9 equivalents or greater and less than about 1.0 equivalent per equivalent of epoxy groups in all the compounds having an epoxy group included in the curable composition. If the content of the curing agent (B) is about 50 parts by mass or greater, curing may be sufficiently proceed, and the cured product may tend to further improve in heat resistance and toughness. If the content of the curing agent (B) is 200 parts by mass or less, discoloration may be suppressed, and the obtained cured product may tend to have excellent hue.

[0068] The proportion of the acid curing agent (B) in the curing agent content of the curable composition may be about 80 mass % or greater, about 85 mass % or greater, about 90 mass % or greater, about 95 mass % or greater, or about 99 mass % or greater with respect to the total curing agent amount (100 mass %). In some embodiments, the proportion of the acid curing agent (B) in the curing agent content of the curable composition may be about 80, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99 mass% or greater, and / or about 100, 99,98, 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81 mass% or less.

[0069] In some embodiments, the curable composition may include 3,4- epoxy cyclohexylmethyl 3, 4-epoxy cyclohexanecarboxy late, methylhexahydrophthalic anhydride, and graphene. In some embodiments, the curable composition may include 3,4- epoxy cyclohexylmethyl 3, 4-epoxy cyclohexanecarboxy late, methylhexahydrophthalic anhydride, graphene, and silica.Graphene (C)

[0070] Graphene is a material having a benzene ring-like structure in which carbon atoms are closely arranged in two-dimensional space. It is a new allotrope of carbon besides zerodimensional fullerene, one-dimensional carbon nanotube, three-dimensional graphite and diamond. Due to its special crystal structure and electronic structure, graphene has excellent electrical, magnetic, thermal and mechanical properties. . Graphene may be a transparent material. Graphene sheets, if fully exposed and reasonably large, may have a theoretical surface area of 2,629 m2 / g (Y. Zhu et al., Ruoff, Carbon-Based Supercapacitors Produced by Activation of Graphene, Science 332 (2011) 1537).

[0071] The term “graphene” used herein may include graphene related materials such as “graphene nano particles.” Graphene has properties that are distinct from those of other carbon materials. In some embodiments, graphene may have more than 90% of which have lateral dimensions (x, y) of about 50 to about 50000 nm and thickness (z) of about 0.34 to about 50 nm, with the lateral dimensions always being larger than the thickness. In some embodiments, graphene may have a thickness (z) from about 0.34 to about 20 nm, or from about 0.34 to about 15 nm. In some embodiments, graphene may preferably have lateral dimensions (x, y) of about 0.5 to about 5 pm.

[0072] The curable composition of the present disclosure may include the graphene (C) as a toughening agent for the curable composition. As used herein, the term “toughening agent” refers to an additive that enhances the impact resistance of the curable composition in which it is incorporated.

[0073] In some embodiments, graphene may be uniformly dispersed in the curable composition. Graphene having a planar chemical structure may provide high mechanical properties and toughness as a nanoscale reinforcement material via a nanofiller effect with theresin formed from the curable composition. In addition, graphene may be nano-dispersed in the highly cross-linked chemical structure of the resin formed from the curable composition including the cycloaliphatic epoxide (A), the effects of graphene, such as imparting mechanical strength and toughness, may be obtained without sacrificing the high heat resistance of the resin, such as high Tg, which may be a characteristic of the resin itself.

[0074] In some embodiments, the curable composition of the present disclosure may preferably include the graphene (C) in an amount from about 0.01 to about 50 % by weight, about 0.1 to about 40 % by weight, about 0.1 to about 30 % by weight, about 0.1 to about 20 % by weight, about 1 to about 40 % by weight, about 2 to about 30 % by weight, about 5 to about 20 % by weight, about 10 to about 15 % by weight with respect to the total amount (100 % by weight) of the cycloaliphatic epoxide (A) and the curing agent (B). In some embodiments, the curable composition of the present disclosure may include the graphene (C) in an amount from about 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 % by weight or more, and / or about 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46,45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20,19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2,0.1, or 0.05 % by weight or less with respect to the total amount (100 % by weight) of the cycloaliphatic epoxide (A) and the curing agent (B). If the content of graphene is withing the above ranges, a cured product obtained by curing the curable composition of the present disclosure may have excellent physical / mechanical properties and toughness while maintaining high heat resistance.

[0075] In some embodiments, adding graphene to the curable composition may increase physical properties of the cured product obtained by curing the curable composition of the present disclosure, such as flexibility, rigidity, and brittleness. In some embodiments, adding graphene to the curable composition may not significantly change a glass transition temperature (Tg) of the curable composition and may maintain relatively constant. In some embodiments, adding other carbon materials, such as graphene oxide, graphite, diamond, carbon fiber, carbon nanotubes, and fullerene, may not increase physical properties of the cured product obtained by curing the curable composition of the present disclosure.

[0076] In some embodiments, graphene may be the only toughening agent included in thecurable composition.Chain Extender (D)

[0077] In some embodiment, the curable composition of the present disclosure may further comprise a chain extender (D). As used herein, the term “chain extender” refers to materials or monomers with several functional groups that allow to attach chemically to the terminal edge of polymer chains in order to add additional chains to improve various properties like molecular weight and mechanical properties.

[0078] As the chain extender (D), a conventional chain extender may be used for the curable composition of the present disclosure. In some embodiment, the chain extender (D) may comprise at least one selected from the group consisting of diol compounds, alkanolamines, diamines, alicyclic diamines, aromatic diamines, aliphatic diamines, and combinations thereof.

[0079] In some embodiment, the chain extender (D) may comprise alkane diols. In some embodiments, the alkane diols may comprise ethylene glycol or 1,4-butanediol. In some embodiments, the diol compounds used for the chain extender may include 1,4-butanediol, 1,3- propanediol, 1,2-propanediol, 1,2-ethylene glycol, 1,6-hexanediol, 1, 4-di (P-hydroxyethyl) hydroquinone, 1,4-di (P-hydroxyethyl), and the like.

[0080] In some embodiments, the alkanolamines used for the chain extender (D) may comprise diethanolamine, triethanolamine, isopropanolamine, or dimethylethanolamine.

[0081] In some embodiment, the diamines used for the chain extender (D) may include tetramethylene diamine, hexamethylene diamine, and the like.

[0082] In some embodiments, the chain extender (D) may include short-chain diols such as aliphatic diols and alicyclic diols, alkanolamines such as diethanolamine, and diamines, aliphatic diamines such as ethylenediamine, C2-C8 alkane diamines such as propylene diamine, tetramethylene diamine and hexamethylene diamine and alicyclic diamines such as 1,4- cyclohexylenediamine, 3-aminomethyl-3,5,5-trimethylcyclohexyl, amine, isophorone diamine, 4,4-dicyclohexylmethane diamine, 1,3-bis (aminomethyl) cyclohexane, norbornane diamine, etc.), aromatic diamines (e.g., phenylene diamine, etc.), araliphatic diamines (e.g., m- xylylenediamine, etc.)] and the like. Of these chain extenders, diols (e.g., alkane diols such as ethylene glycol and 1,4-butanediol), diamines (e.g., tetramethylene diamine, hexamethylene diamine), and the like are widely used. These chain extenders (D) can be used alone or incombination of two or more. The chain extender (D) may be non-aromatic compounds for example, aliphatic or alicyclic compounds from the viewpoint of stability.

[0083] In case where the curable composition includes the chain extender (D), the content of chain extender (D) in the curable composition is not particularly limited, but may be preferably from about 0.1 to about 10 % by weight, about 0.3 to about 5 % by weight, or about 0.5 to about 3 % by weight with respect to the total amount (100 % by weight) of the cycloaliphatic epoxide (A) and the curing agent (B). In some embodiments, the curable composition of the present disclosure may include the chain extender (D) in an amount from about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, or 9.5 % by weight or more and / or about 10, 9.5, 9, 8.5, 8, 7.5, 7, 6.5, 6, 5.5, 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, or 0.2 % by weight or less with respect to the total amount (100 % by weight) of the cycloaliphatic epoxide (A) and the curing agent (B).

[0084] In some embodiments, the curable composition according to the present disclosure may further comprise a low molecular weight compound having one or more hydroxyl groups so that the curable reaction can proceed mildly.Catalyst (E)

[0085] In some embodiments, the curable composition of the present disclosure may further include catalyst (E). As used herein, the term “catalyst” refers to a substance or composition added to a curable composition that speeds up its curing process by initiating a chemical reaction. The catalyst (E) may include a curing accelerator. The curing accelerator may include a compound having a function of accelerating the curing rate when the compound having an epoxy group is cured by the curing agent (B). As the curing accelerator, known or conventional curing accelerators can be used, and are not particularly limited. In some embodiments the catalyst comprises at least one selected from the group consisting of 1,8-diazabicyclo [5.4.0] undecene-7 (DBU), and Salts thereof (e.g., phenol salts, octylates, p-toluenesulfonates, formates, tetraphenylborate salts); 1,5-diazabicyclo [4.3.0] nonene-5 (DBN), and salts thereof (e.g., phenol salt, octylate, p-toluenesulfonate, formate, tetraphenylborate salt); benzyldimethylamine, 2,4,6- tris (dimethylaminomethyl) phenol, N, N-dimethylcyclohexyl Tertiary amines such as amines; 2- ethyl-4-methylimidazole, l-cyanoethyl-2-ethyl-4-methylimidazole, etc. Imidazole compounds; phosphoric acid esters, phosphines such as triphenylphosphine; tetraphenylphosphonium tetra (p-tolyl) phosphonium compounds such as borate, tin octylate, organic metal salts such as zinc octylate; metal chelate and the like. In some embodiments, the curable composition may include one type of curing accelerator or in combination of 2 or more types.

[0086] In the present embodiments, the catalyst (E) or the curing accelerator may comprise at least one selected from the group consisting of U-CAT 12XD™ (trade name, supplied by San- Apro Ltd.), trade names “U-CAT SA 506™,” “U-CAT SA 102™,” “U-CAT 5003™,” “U-CAT 18X™,” “12XD™,” (manufactured by San Apro Co., Ltd.), trade names “TPP-K™,” “TPP- MK™,” (manufactured by Hokuko Chemical Co., Ltd.), trade name “PX-4ET™” (Nippon Chemical Industry) and combination thereof. In some embodiments, the catalyst may comprise U-CAT 12XD™ (trade name, supplied by San- Apro Ltd.).In some embodiments, the curable composition may comprise the catalyst (E) in an amount from about 0.05 to about 5 % by weight based on the total amount (100 parts by weight) of the cycloaliphatic epoxide. The curable composition may comprise the catalyst (E) in an amount of about 5 parts by weight, about 0.1 to about 3 parts by weight, about 0.2 to 3 parts by weight, or about 0.25 to about 2.5 parts by weight based on the total amount (100 parts by weight) of the cycloaliphatic epoxide. In some embodiments, the curable composition may comprise the catalyst (E) in an amount of about 0.05, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4 or 4.5 parts by weight or more and / or about 5, 4.5, 4. 3.5, 3, 2.5, 2, 1.5, 1, 0.5 or 0.1 parts by weight or less based on the total amount (100 parts by weight) of the cycloaliphatic epoxide. When the usage-amount of a hardening accelerator is less than 0.05 weight part, the hardening promotion effect may become inadequate. On the other hand, when the usage-amount of a hardening accelerator exceeds 5 weight part, a hardened cured material may color, and a hue may deteriorate.Silica (F)

[0087] In some embodiments, the curable composition of the present disclosure further comprise silica (F). Silica (F) may improve performance of the curable composition by ensuring a uniform distribution of the components in the curable composition. As the silica (F), a well- known or commonly used silica can be used. In some embodiments, the silica (F) may comprise silica (SiCh).

[0088] The silica is not particularly limited, and well-known or commonly used silica such asfused silica, crystalline silica, and high-purity synthetic silica can be used. As the silica, silica subjected to a well-known or commonly used surface treatment (for example, a surface treatment with a surface treatment agent such as a metal oxide, a silane coupling agent, a titanium coupling agent, an organic acid, a polyol, or silicone) can also be used.

[0089] Examples of the silica include hydrophilic silica and hydrophobic silica, and hydrophobic silica is preferable from the viewpoint of easily increasing the viscosity of the curable composition, suppressing sedimentation of solid components such as the microcapsuletype latent curing agent to improve the dispersibility, and imparting thixotropy to the curable composition to achieve excellent workability such impregnation and casting properties.

[0090] The hydrophobic silica is silica obtained by subjecting hydrophilic silica to a hydrophobization treatment. Examples of the treatment agent used in the hydrophobization treatment include organic silyl compounds such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, hexamethyldisilazane, methyltrialkoxysilane, dimethyldialkoxysilane, trimethylalkoxysilane, ethyltrichlorosilane, propyltrichlorosilane, hexyltrichlorosilane, long- chain alkyltrichlorosilane, ethyltrialkoxysilane, propyltrialkoxysilane, hexyltrialkoxysilane, long- chain alkyltrialkoxysilane, methacrylsilane, fluoroalkylsilane, and perfluoroalkylsilane and silicone compounds such as dimethylpolysiloxane (silicone oil), methylphenylpolysiloxane, methylhydrogenpolysiloxane, and polysiloxanes of amino-modified silicone and the like. Among these, polysiloxanes are preferably used in the hydrophobization treatment. As the hydrophobization treatment method, a well-known method can be used to perform a hydrophobization treatment, and examples of the method include a liquid phase method, a gas phase method, and an autoclave method.

[0091] The shape of the silica is not particularly limited, and examples of the shape include a powder shape, a round shape, a crushed shape, a fibrous shape, a needle shape, and a scaly shape. Among these, round silica is preferable, and spherical silica (for example, round silica having an aspect ratio of 1.2 or less) is particularly preferable, from the viewpoint of dispersibility.

[0092] The specific surface area of the silica is not particularly limited, but may be preferably about 10 m2 / g or greater, about 40 m2 / g or greater, about 70 m2 / g or greater, about 100 m2 / g or greater, 400 m2 / g or greater, or about 500 m2 / g or greater and / or 1,000 m2 / g or less, about 500 m2 / g or less, about 400 m2 / g or less, about 100 m2 / g or less, about 70 m2 / g, or 40 m2 / g or less.from the viewpoint of imparting thixotropy to the curable composition to achieve excellent workability such as impregnation and casting properties.

[0093] The median particle size of the silica is not particularly limited, but may be 200 nm or less, 100 nm or less, or 50 nm or less, from the viewpoint of imparting thixotropy to the curable composition to achieve excellent workability such as impregnation and casting properties. The median particle size may be, for example, 3 nm or greater. The median particle size may be from 0.1 to 50 pm, or from 0.1 to 30 pm from the viewpoint of improving the low linear expansivity, the strength, and the crack resistance of the cured product. The median particle size means a particle size at an integrated value of 50% in a particle size distribution (median diameter) measured with a laser diffraction / scattering method.

[0094] In a case where the curable composition may include the silica (F), the proportion of the content of the silica (F) in the curable composition is not particularly limited, but may be from about 0.1 to about 20 % by weight, about 0.5 to about 15 % by weight, about 1 to about 10 % by weight, about 1 to about 5 % by weight, about 3 to 8 % by weight with respect to the total amount (100 % by weight) of the curable composition. In some embodiments, proportion of the content of the silica (F) in the curable composition may be about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 14, 15, 16, 17, 18, 19, or 20 % by weight or more, and / or about 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2 or 0.1 % by weight or less with respect to the total amount (100 % by weight) of the cycloaliphatic epoxide (A), the curing agent (B) and the graphene (C).

[0095] In case where the curable composition includes silica, the content of silica in the curable composition is not particularly limited, but may be preferably from about 0.1 to about 20 % by weight, about 0.1 to about 10 % by weight, about 0.1 to about 5 % by weight, about 0.3 to about 3 % by weight, about 0.5 to about 2 % by weight, about 0.5 to about 15 % by weight, about 1 to about 10 % by weight, or about 3 to 8 % by weight with respect to the total amount (100 % by weight) of the total amount (100 % by weight) of the cycloaliphatic epoxide (A), the curing agent (B) and the graphene (C). In some embodiments, proportion of the content of silica in the curable composition may be about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 14, 15, 16, 17, 18, 19, or 20 % by weight or more, and / or about 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2 or 0.1 % by weight or less with respect to the total amount (100 % by weight) of the curable composition.If the content of graphene is withing the above ranges, a cured product may have excellent physical / mechanical properties and toughness while maintaining high heat resistance.

[0096] In case where the curable composition includes silica, a weight ratio of graphene to silica may be in a range from about 1 : 99 to about 99: 1. In some embodiments, the weight ratio of graphene to silica in the curable composition may be about 1 :99, 5:95, 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 55:45, 60:40, 65:35, 70:30, 75:25, 80:20, 85:15, 90:10, 95:5 or 99: 1. In certain embodiments, the weight ratio of the graphene to silica in the curable composition may be about 1 :1, 2: 1. 3:1, 4: 1, 5: 1, 6:1, 7: 1, 8:1, 9: 1 or 10:1.

[0097] In some embodiments, the curable composition excludes fillers. In some embodiments, the curable composition excludes fillers other than silica.Dispersing Agent (G)

[0098] In some embodiments, the curable composition of the present disclosure further comprise a dispersing agent (G). Dispersing agent (G) may improve performance of the curable composition by ensuring a uniform distribution of the components in the curable composition. As the dispersing agent (G), a well-known or commonly used dispersing agent can be used. In some embodiments, the dispersing agent (G) may comprise inorganic compounds. In some embodiments, the inorganic compounds for the dispersing agent (G) may include, but are not particularly limited to, powders of alumina, zircon, calcium silicate, calcium phosphate, calcium carbonate, magnesium carbonate, silicon carbide, silicon nitride, aluminum nitride, boron nitride, aluminum hydroxide, iron oxide, zinc oxide, zirconium oxide, magnesium oxide, titanium oxide, aluminum oxide, calcium sulfate, barium sulfate, forsterite, steatite, spinel, clay, kaolin, dolomite, hydroxyapatite, nepheline syenite, cristobalite, wollastonite, diatomaceous earth, talc, phenyl ether and the like, and molded bodies (for example, spheroidized beads) thereof. In some embodiments, the dispersing agent (G) may include those obtained by well-known or commonly used surface treatment of an inorganic filler. In some embodiments, the curable composition of the present disclosure may include a single type of the dispersing agent (G), or two or more types of the dispersing agent (G). Among these dispersing agent, alumina, and aluminum nitride may be used. In some embodiments, the curable composition of the present disclosure may include a polyoxyethylene styrenated phenyl ether.

[0099] In case where the curable composition includes the dispersing agent (G), the content ofdispersing agent (G) in the curable composition is not particularly limited, but may be preferably from about 0.1 to about 25 % by weight, about 1 to about 20 % by weight, or about 2 to about 12 % by weight with respect to the total amount (100 % by weight) of the cycloaliphatic epoxide (A) and the curing agent (B). In some embodiments, the curable composition of the present disclosure may include the dispersing agent (G) in an amount from about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24 % by weight or more and / or 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, or 0.2 % by weight or less with respect to the total amount (100 % by weight) of the cycloaliphatic epoxide (A) and the curing agent (B).Other Components

[0100] In some embodiments, the curable composition may consist essentially of: a cycloaliphatic epoxide (A) having an alicyclic structure and an epoxy group in a molecule, a curing agent (B), graphene as a toughening agent (C), a chain extender (D), and a catalyst (E). In some embodiments, the curable composition may consist of: a cycloaliphatic epoxide (A) having an alicyclic structure and an epoxy group in a molecule, a curing agent (B), graphene as a toughening agent (C), a chain extender (D), and a catalyst (E). In some embodiments, the curable composition may consist essentially of: a cycloaliphatic epoxide (A) having an alicyclic structure and an epoxy group in a molecule, a curing agent (B), graphene as a toughening agent(C), a chain extender (D), a catalyst (E), and silica (F). In some embodiments, the curable composition may consist of: a cycloaliphatic epoxide (A) having an alicyclic structure and an epoxy group in a molecule, a curing agent (B), graphene as a toughening agent (C), a chain extender (D), a catalyst (E), and silica (F). In some embodiments, the curable composition may consist essentially of: a cycloaliphatic epoxide (A) having an alicyclic structure and an epoxy group in a molecule, a curing agent (B), graphene as a toughening agent (C), a chain extender(D), a catalyst (E), silica (F), and a dispersing agent (G). In some embodiments, the curable composition may consist of: a cycloaliphatic epoxide (A) having an alicyclic structure and an epoxy group in a molecule, a curing agent (B), graphene as a toughening agent (C), a chain extender (D), a catalyst (E), silica (F), and a dispersing agent (G). In the curable composition that consists essentially of the recited ingredients may not exclude additives and minor impurities from the curable composition, which do not materially alter the basic and novel properties of thecurable composition. The basis and novel properties of the curable composition may include such as mechanical properties, toughness and heat resistance of cured product obtained from the curable composition and curability of the curable composition.

[0101] In some embodiment, the curable composition may include another component in addition to the above-described components. In addition, common additives can be used such as antifoamers such as silicone-based and fluorine-based antifoamers, leveling agents, coupling agents such as silane coupling agents of y-glycidoxypropyltrimethoxysilane, 3- mercaptopropyltrimethoxysilane, and the like, surfactants, flame retardants, colorants, antioxidants, ultraviolet absorbers, ion adsorbents, coloring agents, phosphors (for example, inorganic phosphor fine particles such as YAG-based phosphor fine particles and silicate-based phosphor fine particles), mold release agents, thickeners, dispersants, rust inhibitors, corrosion inhibitors, freezing point depressants, and antiwear additives, as long as the viscosity and the transparency are not impaired.

[0102] If an antioxidant described above is included, a cured product further excellent in heat resistance (in particular, yellowing resistance) may be formed. As the antioxidant, a well-known or commonly used antioxidant can be used. Examples of the antioxidant include, but are not particularly limited to, phenol-based antioxidants (phenol-based compounds), hindered amine- based antioxidants (hindered amine-based compounds), phosphorous-based antioxidants (phosphorous-based compounds), and sulfur-based antioxidants (sulfur-based compounds).

[0103] Examples of the phenol-based antioxidants include monophenols such as 2,6-di-t-butyl- p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-p-ethylphenol, and stearyl-[3-(3,5-di-t-butyl-4- hydroxyphenyl) propionate; bis-phenols such as 2,2'-methylene-bis(4-methyl-6-t-butylphenol), 2,2'-methylene-bis(4-ethyl-6-t-butylphenol), 4,4'-thio-bis(3-methyl-6-t-butylphenol), 4,4'- butylidene bis(3-methyl-6-t-butylphenol), and 3,9-bis[l,l-dimethyl-2-{P-(3-t-butyl-4-hydroxy-5- methylphenyl)propionyloxy} ethyl] 2,4,8,10-tetraoxaspiro [5.5]undecane; and polymeric phenols such as l,l,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl) butane, l,3,5-trimethyl-2,4,6-tris(3,5-di- t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'- hydroxyphenyl)propionate] methane, bis [3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid] glycol ester, 1,3,5-tris (3',5'-di-t-butyl-4'-hydroxybenzyl)-s-triazine-2,4,6-(lH,3H,5H) trione, and tocophenol.

[0104] Examples of the hindered amine-based antioxidants include bis (1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis (1,1-dimethyl ethyl)-4-hydroxyphenyl]methyl]butyl malonate, bis(l,2,2,6,6- pentamethyl-4-piperidyl) sebacate, methyl-l,2,2,6,6-pentamethyl-4-piperidyl sebacate, and 4- benzoyloxy-2,2,6,6-tetramethylpiperidine.

[0105] Examples of the phosphorous-based antioxidants include phosphites (phosphite-based antioxidants) such as triphenyl phosphite, diphenylisodecyl phosphite, phenyldiisodecyl phosphite, tris(nonylphenyl) phosphite, diisodecyl pentaerythritol phosphite, tris(2,4-di-t- butylphenyl) phosphite, cyclic neopentanetetrayl bis(octadecyl)phosphite, cyclic neopentanetetrayl bis (2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetrayl bis (2,4-di-t- butyl-4-methylphenyl) phosphite, and bis [2-t-butyl-6-methyl-4- {2- (octadecyloxycarbonyl)ethyl}phenyl] hydrogen phosphite; and oxaphosphaphenanthrene oxides such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 10-(3,5-di-t-butyl-4- hydroxybenzyl)-9, 10-dihydro-9-oxa- 10-phosphaphenanthrene- 10-oxide.

[0106] Examples of the sulfur-based antioxidants include dodecanethiol, dilauryl-3,3'- thiodipropionate, dimyristyl-3,3'-thiodipropionate, and distearyl-3,3'-thiodipropionate.

[0107] Among these, the antioxidant preferably includes a phosphorous-based antioxidant, and more preferably includes a phosphite-based antioxidant from the viewpoint of further improving the heat resistance of the cured product.

[0108] In a case where the curable composition includes an antioxidant, the content (blending amount) of the antioxidant in the curable composition is not particularly limited, but is preferably from 0.1 to 5 % by weight and more preferably from 0.5 to 3 % by weight with respect to 100 % by weight of the curable composition. If the content of the antioxidant is 0.1 parts by mass or greater, the cured product is efficiently prevented from oxidation, and tends to have heat resistance and yellowing resistance that are further improved. If the content of the antioxidant is 5 parts by mass or less, discoloration is suppressed, and a cured product having further good hue tends to be easily obtained.

[0109] The curable composition can be, but is not particularly limited to, one prepared by stirring and mixing the above-described components under heating as necessary. The curable composition can be used as a one-part composition, which contains components mixed beforehand and is used as is, or alternatively, used as a multi-part (for example, two-part) composition of which two or more components having been separately stored are mixed for use before use. The stirring and mixing method is not particularly limited, and a well-known orcommonly used stirring and mixing unit can be used, for example, including a mixer of various types, such as a dissolver and a homogenizer; a kneader; a roll mill; a bead mill; and a rotation / revolution stirring apparatus. In addition, after the stirring and mixing, the mixture may be defoamed under vacuum.

[0110] In some embodiments, the curable composition of the present disclosure may exclude oxetane or a compound including oxetane unit.

[0111] In some embodiments, the curable composition of the present disclosure may exclude a bio-based epoxy compound. In some embodiments, the curable composition of the present disclosure may exclude an epoxy compound having a tetrahydrofuran ring.

[0112] In some embodiments, the curable composition of the present disclosure may exclude a compound having a polyalkylene glycol unit.Cured Product

[0113] In some embodiment, the present disclosure relates to a cured product of the curable composition or an article of the cured product. In some embodiments, the present disclosure relates to a method of producing a molded article comprising: ejecting the curable composition; curing the ejected curable composition; and forming a molded article from the curable composition.

[0114] By curing the curable composition of the present disclosure, a cured product having excellent heat resistance can be obtained. As a method of curing, a well-known or commonly used method such as heat treatment can be used. The temperature during curing by heating (curing temperature) is not particularly limited, but may be from about 45 to 200° C., from about 50 to 190° C., and from about 55 to 180° C. The heating time (curing time) during curing is not particularly limited, but may be from about 30 to 600 minutes, from about 45 to 540 minutes, and from about 60 to 480 minutes. If the curing temperature and the curing time are about 45° C or higher, curing is sufficient, and if the curing temperature is about 200° C or lower, decomposition of the resin component can be suppressed. Although the curing conditions depend on various conditions, the curing conditions can be appropriately adjusted, for example, by shortening the curing time when the curing temperature is increased, or increasing the curing time when the curing temperature is reduced. The curing can be performed in one step or in multiple steps of two or more steps.

[0115] The cured product may have a glass transition temperature (Tg) of about 180 °C or higher, about 190 °C or higher, 200 °C. or higher, or about 210 °C or higher. If the glass transition temperature is 180° C or higher, the heat resistance of the cured product may be excellent even in the case of an environment of a temperature of 180° C or higher, such as the operating environment temperature of an EV motor. The glass transition temperature of the cured product is a value measured with a DSC (differential scanning calorimeter).

[0116] The cured product of the present disclosure may have a bending strain at 23 °C of about 2.0% or greater, about 3.0 % or greater, about 4.0% or greater, and about 4.3 % or greater. If the bending strain is 2.0% or greater (in particular, 4.0% or greater), the flexibility in an ordinary temperature environment is improved to achieve excellent toughness. The bending strain at 23 °C can be measured in accordance with JIS K 7171 (2008).

[0117] The cured product may have a bending strain at 150 °C of about 2.0 % or greater, about 4.4 % or greater, about 5.0 % or greater, and about 5.4 % or greater. If the bending strain is 2.0 % or greater (in particular, 4.4 % or greater), excellent flexibility and excellent toughness are achieved even in the case of an environment of a temperature of 180 °C or higher, such as the operating environment temperature of an EV motor. The bending strain at 150 °C can be measured in accordance with JIS K 7171 (2008).

[0118] The curable composition and the cured product may be used in a part included in a rotary electric machine (for a rotary electric machine). The cured product of the present disclosure may have excellent heat resistance, and therefore can be preferably used in a part used in a high heat environment, in particular in an automobile part (for example, for an automobile EV motor). Specific usage aspects of the cured product include insulating materials, coating materials, and adhesives. The curing agent composition including the acid anhydride-based curing agent (B) and the graphene (C) may have a long shelf life and is less likely to thicken during storage, and therefore the curable composition obtained by mixing the curing agent composition and the epoxy compound (A) may have excellent wettability and an excellent impregnation property to an object to which the curable composition is to be applied. Therefore, the curable composition can be preferably used in processes such as atmospheric pressure impregnation, vacuum impregnation, pressure impregnation, and dipping.

[0119] The curable composition and the cured product may be used in a rotary electric machine as described above, for example, for protecting a rotor wire (for covering a winding, awinding tip, and the like), for impregnating / casting a stator coil, for impregnating / casting and covering the entire stator, for fixing a magnet in a rotor and / or a stator to fix a magnet inserted into a hole provided in a rotor core or a stator core to an inner wall of the hole, and for filling a gap between the hole and the magnet.

[0120] In particular, the curable composition and the cured product may be used for impregnating a coil to impregnate / cast a coil (wire, winding) in a stator or a rotor of a rotary electric machine.

[0121] By using the cured product in the rotary electric machine, a rotary electric machine can be obtained that includes the cured product in a form such as a rotor for a rotary electric machine including the cured product covering a winding of the rotor; a stator for a rotary electric machine including the cured product that is formed to cover a stator coil; a stator for a rotary electric machine including the cured product covering the entire stator; a rotor or a stator for a rotary electric machine including a rotor core or a stator core having a hole, a magnet inserted into the hole, and the cured product adhering the magnet to an inner wall of the hole; or a rotor or a stator for a rotary electric machine including a rotor core or a stator core having a hole, a magnet inserted into the hole, the cured product with which a gap between the magnet and an inner wall of the hole is filled.

[0122] Each aspect disclosed in the present specification can be combined with any other feature disclosed herein. Note that each of the configurations, combinations thereof, or the like in each of the embodiments are examples, and additions, omissions, replacements, and other changes to the configurations may be made as appropriate without departing from the spirit of the present disclosure. In addition, each aspect of the invention according to the present disclosure is not limited by the embodiments or the following examples but is limited only by the claims.EXAMPLES

[0123] Some embodiments of the present disclosure will be described in further detail below based on examples.Preparation of Curable CompositionExamples 1 to 6

[0124] Graphene nano particles were uniformly mixed with a cycloaliphatic epoxide (trade name “Celloxide 2021P”, available from Daicel Corporation) in a blending proportion (unit: % by weight) shown in Table 1. Next, an acid-anhydride-based curing agent was uniformly mixed using a rotation / revolution stirring apparatus (trade name “THINKY MIXER AR-250”, available from THINKY CORPORATION), and the mixture was defoamed to prepare a curable composition.Comparative Example 1

[0125] A curable composition and a cured product are prepared in the same manner as in Example 1 except for changing the composition of the curable composition to the composition without graphene.

[0126] Table 1(% by weight with respect to 100 % of the cycloaliphatic epoxide (A))*14-methylhexahydrophthalic anhydride / hexahydrophthalic anhydride = 70 / 30*2Product by San-Apro Ltd.*3The diameter of the GrapheneBlack is 0.5 to 1.0pm.Preparation of Cured Product

[0127] The curable compositions obtained above were heated at 100 °C for 2 hour, and at 150 °C for 2 hour continuously using an oven and thus cured to prepare a cured product.Evaluation

[0128] The curable compositions and the cured products obtained in Examples 1 to 6 and Comparative Example 1 were subjected to the following evaluation tests.Viscosity at 25 °C

[0129] The viscosity of each curable composition at 25 °C were measured using a digital viscometer (model No. “DVU-EII”, available from TOKIMEC INC.) under conditions: rotor: standard 1° 34'xR24; temperature: 25 °C; rotation speed: from 0.5 to 10 rpm.Epoxy Equivalent

[0130] The epoxy equivalent of the cycloaliphatic epoxide was measured in accordance with HS K7236.Water Content (%)

[0131] The residual water content was measured by the Karl Fisher method.Glass Transition Temperature

[0132] The glass transition temperature of each cured product was measured using a differential scanning calorimeter (trade name “Q2000,” available from TA Instruments Inc.) as follows. A pretreatment was implemented (in which the temperature was increased from 30 °C to 250 °C at a temperature increase rate of 10 °C / min, and then decreased from 250 °C to 30 °C at a temperature decrease rate of -10 °C / min), and then the glass transition temperature was measured in a nitrogen stream in a measurement temperature range of from 30 to 250 °C at a temperature increase rate of 10° C / min. The temperature at the inflection point of the obtained temperature thermal history curve was then determined as the glass transition temperature.Bending Strain

[0133] The bending strain of each cured product was measured in accordance with JIS K 7171 (2008).

[0134] The results were shown in Tables 2 and 3 and Figures 1-6.

[0135] Table 2

[0136] Table 3

[0137] Figure 1 illustrates the appearance of the cured products when adding 10% or 20% of graphene was added to the mixture of Celloxide 202 IP and the acid-anhydride-based curing agent.

[0138] Figure 2 is a graph showing that a glass transition temperature (Tg) was not significantly decreased by adding graphene (10%, Example 5 or 20%, Example 6) to the mixture of Celloxide 202 IP. The data indicated that the physical properties such as flexibility, rigidity, and brittleness remain of the cured product of the curable composition of the present disclosure would be relatively constant by including graphene.

[0139] Figure 3 is a thermomechanical analysis (TMA) test result of the cured product of thecurable compositions including 10% or 20% of graphene. As shown in Table 2, the physical properties including the bending strength, the bending modulus, and the bending strain were improved when graphene was added to the mixture of Celloxide 202 IP and the acid-anhydride- based curing agent. As shown in Table 3, the heat resistance was also improved when graphene was added to the mixture of Celloxide 202 IP and the acid-anhydride-based curing agent. The thermomechanical analysis (TMA) and the coefficient of thermal expansion (CTE) (al, a2) were almost the same even if graphene was added. These results show that adding graphene to the curable composition improves performance of the curable composition and the cycloaliphatic epoxide, including modulus, toughness and heat resistance of the cured product.Examples 7 and 8

[0140] The curable compositions were prepared in the same manner as Example 1 except that 5% graphene and silica or a dispersing agent were added as described in Table 4 below. The results were shown in Table 4 and Figure 7.Comparative Examples 2

[0141] The curable compositions were prepared in the same manner as Example 1 except that 5% graphene and 0% EHPE3150 (Comparative Example 2), 20% EHPE3150 (Comparative Example 3) or 30% EHPE3150 (Comparative Example 4) were added. The results were shown in Figure 7.

[0142] Table 4(% by weight with respect to 100 % of the cycloaliphatic epoxide (A))* Curing condition: 100 °C for 2 hours and 150 °C for 2 hours.** DSP9: polyoxyethylene styrenated phenyl etherExamples 9 to 11

[0143] The curable compositions were prepare in the same manner as Example 1 except that 5%, 11% and 25% of graphene and 2.1%, 2.2% and 2.5% of silica were added as described in Table 5 below.

[0144] Table 5The viscosity of the composition obtained in Example 10 was 628 mPa • s.Preparation of Cured Product

[0145] The curable composition obtained above heated at 100 °C for 2 hour, and at 150 °C for 2 hour continuously using an oven and thus cured to prepare a cured product.Evaluation

[0146] The cured products obtained in Examples 9 to 10 and Comparative Example 3 were subjected to the following evaluation tests. The results were shown in Table 6.

[0147] Table 6

[0148] As illustrated in Figure 7, adding silica to the curable composition prevents sedimentation of graphene in the curable composition without significantly changing viscosity of the curable composition. Moreover, the cured product obtained by curing the curable composition including silica possessed significantly improved appearance as compared with the cured product obtained by curing the curable composition without silica. These data demonstrated that adding a combination of graphene and silica to the curable composition provides not only the improved mechanical properties of the cured product but also excellent toughness and appearance of the cured product of the present curable composition.Additional Examples

[0149] Some embodiments of the present disclosure will be described in further detail below based on the previous Examples and Comparative Examples.Comparative Example APreparation of Curable Compositions and Preparation of Cured Products

[0150] Curable compositions are prepared in the same manner as Example 1 except for graphene oxide is used instead of graphene nano particles as summarized in Table 7 below(unit: % by weight). In particular, graphene oxide are uniformly mixed with a cycloaliphatic epoxide (trade name “Celloxide 202 IP”, available from Daicel Corporation) in a blending proportion (unit: % by weight) shown in Table 7. Next, an acid-anhydride-based curing agent is uniformly mixed using a rotation / revolution stirring apparatus (trade name “THINKY MIXER AR-250”, available from THINKY CORPORATION), and the mixture is defoamed to prepare a curable composition. The viscosity of the mixture is increased and the mixture is not able to be molded due to lack of liquidity because graphene oxide has carboxyl group and reacts with epoxy group in a short period of time.

[0151] The curable composition obtainable above heats at 100 °C for 2 hours, and at 150 °C for 2 hours continuously using an oven and thus cures to prepare a cured product.Comparative Example BPreparation of Curable Compositions and Preparation of Cured Products

[0152] Curable compositions are prepared in the same manner as Example 1 except for graphite is used instead of graphene nano particles as summarized in Table 7 below (unit: % by weight). In particular, graphene oxide are uniformly mixed with a cycloaliphatic epoxide (trade name “Celloxide 2021P”, available from Daicel Corporation) in a blending proportion (unit: % by weight) shown in Table 7. Next, an acid-anhydride-based curing agent is uniformly mixed using a rotation / revolution stirring apparatus (trade name “THINKY MIXER AR-250”, available from THINKY CORPORATION), and the mixture is defoamed to prepare a curable composition.

[0153] The curable composition obtainable above heats at 100 °C for 2 hours, and at 150 °C for 2 hours continuously using an oven and thus cures to prepare a cured product. As a result of this, appearance of a cured product is not uniform because of low dispersibility and sedimentation of Graphite.Comparative Example CPreparation of Curable Compositions and Preparation of Cured Products

[0154] Curable compositions are prepared in the same manner as Example 1 except for diamond is used instead of graphene nano particles as summarized in Table 7 below (unit: % byweight). In particular, graphene oxide are uniformly mixed with a cycloaliphatic epoxide (trade name “Celloxide 2021P”, available from Daicel Corporation) in a blending proportion (unit: % by weight) shown in Table 7. Next, an acid-anhydride-based curing agent is uniformly mixed using a rotation / revolution stirring apparatus (trade name “THINKY MIXER AR-250”, available from THINKY CORPORATION), and the mixture is defoamed to prepare a curable composition. The viscosity of the mixture is increased and the mixture is not able to be molded due to lack of liquidity because graphene oxide has carboxyl group and reacts with epoxy group in a short period of time.

[0155] The curable composition obtainable above heats at 100 °C for 2 hours, and at 150 °C for 2 hours continuously using an oven and thus cures to prepare a cured product. As a result of this,

[0156] The cured product has lower mechanical properties and impact strength than a product including graphene because the structure of Diamond is three dimensional and not planar like graphene.Comparative Example DPreparation of Curable Compositions and Preparation of Cured Products

[0157] Curable compositions are prepared in the same manner as Example 1 except for carbon fiber is used instead of graphene nano particles as summarized in Table 7 below (unit: % by weight). In particular, graphene oxide are uniformly mixed with a cycloaliphatic epoxide (trade name “Celloxide 2021P”, available from Daicel Corporation) in a blending proportion (unit: % by weight) shown in Table 7. Next, an acid-anhydride-based curing agent is uniformly mixed using a rotation / revolution stirring apparatus (trade name “THINKY MIXER AR-250”, available from THINKY CORPORATION), and the mixture is defoamed to prepare a curable composition.

[0158] The curable composition obtainable above heats at 100 °C for 2 hours, and at 150 °C for 2 hours continuously using an oven and thus cures to prepare a cured product. As a result of this, appearance of a cured product is not uniform because of low dispersibility and sedimentation of carbon fiber.Comparative Example EPreparation of Curable Compositions and Preparation of Cured Products

[0159] Curable compositions are prepared in the same manner as Example 1 except for carbon nanotube is used instead of graphene nano particles as summarized in Table 7 below (unit: % by weight). In particular, graphene oxide are uniformly mixed with a cycloaliphatic epoxide (trade name “Celloxide 2021P”, available from Daicel Corporation) in a blending proportion (unit: % by weight) shown in Table 7. Next, an acid-anhydride-based curing agent is uniformly mixed using a rotation / revolution stirring apparatus (trade name “THINKY MIXER AR-250”, available from THINKY CORPORATION), and the mixture is defoamed to prepare a curable composition.

[0160] The curable composition obtainable above heats at 100 °C for 2 hours, and at 150 °C for 2 hours continuously using an oven and thus cures to prepare a cured product. As a result of this, appearance of a cured product is not uniform because of low dispersibility and sedimentation of carbon nanotube.Comparative Example FPreparation of Curable Compositions and Preparation of Cured Products

[0161] Curable compositions are prepared in the same manner as Example 1 except for fullerene is used instead of graphene nano particles as summarized in Table 7 below (unit: % by weight). In particular, graphene oxide are uniformly mixed with a cycloaliphatic epoxide (trade name “Celloxide 2021P”, available from Daicel Corporation) in a blending proportion (unit: % by weight) shown in Table 7. Next, an acid-anhydride-based curing agent is uniformly mixed using a rotation / revolution stirring apparatus (trade name “THINKY MIXER AR-250”, available from THINKY CORPORATION), and the mixture is defoamed to prepare a curable composition.

[0162] The curable composition obtainable above heats at 100 °C for 2 hours, and at 150 °C for 2 hours continuously using an oven and thus cures to prepare a cured product. As a result of this,

[0163] The cured product has lower mechanical properties than a product including graphene because the structure of fullerene is three dimensional and not planar like graphene.

[0164] Table ?

[0165] As described above, the cured products obtained in Examples 1 to 11 have high mechanical properties. In addition, since the cured products obtained in Examples 1 to 11 have at least high impact strength, the cured products exhibit excellent in toughness. Moreover, since the cured products obtained in Examples 1 to 11 have at least a high glass transition temperature (Tg) in DMA and a high glass transition temperature (Tg) in TMA, the cured products can maintain high heat resistance.

[0166] (Cycloaliphatic Epoxide)Celloxide 2021P: Trade name “Celloxide 2021P” (3,4-epoxycyclohexylmethyl(3,4- epoxy)cyclohexanecarboxylate, available from Daicel Corporation

[0167] (Acid Anhydride Curing Agent)NMA: Trade name “NMA,” available from Dixie Chemical, methylnadic anhydrideHHPA7030 NC: Trade name “HHPA 7030 NC”, available from Dixie Chemical, mixture of hexahydrophthalic anhydride and methylhexahydrophthalic anhydrideECA100: Trade name “ECA 100”, available from Dixie Chemical, mixture of methyltetrahydrophthalic anhydride and tetrahydrophthalic anhydrideHN-5500N: Trade name “HN-5500N”, available from Hitachi Chemical Co., Ltd., methylhexahydrophthalic anhydride

[0168] (Curing Accelerator)1-MI: 1 -methylimidazole2-MI: 2-methylimidazole2E4MZ: 2-ethyl-4-methylimidazoleHPI: l-(2-hydroxypropyl)imidazoleLC-80: Trade name “Technicure LC-80”, available from A & C Catalysts, amine adduct of 2- methylimidazole and bisphenol A type epoxy compound, latent curing acceleratorPX-4ET: Trade name “PX-4ET”, tetrabutylphosphonium diethyl phosphodithionate, available from NIPPON CHEMICAL INDUSTRIAL CO., LTD.

[0169] (Additive)R202: Trade name “AEROSIL R202”, available from Evonik Industries AG, fumed silicaTS-720: Trade name “CAB-O-SIL TS-720”, available from Cabot Corporation, fumed silicaBYK378: Trade name “BYK-378”, available from BYK Japan KKBYK506: Trade name “BYK-A 506”, available from BYK Japan KKBYK525: Trade name “BYK-A 525”, available from BYK Japan KK

[0170] EMBODIMENTSEmbodiment 1. A curable composition comprising:a cycloaliphatic epoxide; a curing agent; and graphene.Embodiment 2. The curable composition according to embodiment 1, wherein the cycloaliphatic epoxide comprises a compound represented by Formula (I):wherein, in Formula (I),X is a single bond or a linkage group, and optionally substituents is bonded to one or more of carbon atoms constituting cyclohexane ring.Embodiment 3. The curable composition according to embodiment 2, wherein in Formula (I), the linkage group comprises a divalent group.Embodiment 4. The curable composition according to embodiment 3, wherein the divalent group comprises at least one selected from the group consisting of: a divalent hydrocarbon group; an epoxidized alkenylene group in which some or all of the carbon-carbon double bonds are epoxidized; a carbonyl group; an ether bond; an ester bond; a carbonate group; an amido group; and combinations thereof.Embodiment 5. The curable composition according to embodiment 4, wherein the divalent hydrocarbon group comprises a linear or branched alkylene group having from 1 to 8 carbon atoms or a divalent alicyclic hydrocarbon group.Embodiment 6. The curable composition according to embodiment 5, wherein the linear or branched alkylene group having from 1 to 8 carbon atoms comprises at least one selected from the group consisting of a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, a trimethylene group, and combinations thereof.Embodiment 7. The curable composition according to embodiment 5, wherein the divalent alicyclic hydrocarbon group comprises a divalent cycloalkylene.Embodiment 8. The curable composition according to embodiment 5, wherein the divalent alicyclic hydrocarbon group comprises at least one selected from the group consisting of 1,2- cyclopentylene, 1,3-cyclopentylene, cyclopentylidene, 1 ,2-cyclohexylene, 1,3 -cyclohexylene, 1,4-cyclohexylene, cyclohexylidene, and combinations thereof.Embodiment 9. The curable composition according to embodiment 4, wherein an alkenylene group of the epoxidized alkenylene group comprises linear or branched alkenylene groups having from 2 to 8 carbons.Embodiment 10. The curable composition according to embodiment 4, wherein an alkenylene group of the epoxidized alkenylene group comprises at least one selected from the group consisting of a vinylene group, a propenylene group, a 1 -butenylene group, a 2-butenylene group, a butadienylene group, a pentenylene group, a hexenylene group, a heptenylene group, an octenylene group, and combinations thereof.Embodiment 11. The curable composition according to any one of embodiments 2 to 10, wherein the linkage group comprises an oxygen.Embodiment 12. The curable composition according to any one of embodiments 2 to 11, wherein the linkage group comprises at least one selected from the group consisting of — (CH2)X— (l<x<20), a cycloalkyl group having C3 to CIO alkyl such as cyclohexyl, — COO — CH2— , —CO—, — O— CO— O— , —COO—, — O— , — O— R— (R = Cl to C8 alkylene), — CONH — and combinations thereof.Embodiment 13. The curable composition according to any one of the preceding embodiments, wherein the cycloaliphatic epoxide comprises 3, 4-epoxy cyclohexylmethyl 3 ^d’epoxy cyclohexanecarboxylate represented by formula (1-1) below:Embodiment 14. The curable composition according to any one of the preceding embodiments, wherein the cycloaliphatic epoxide comprises at least one selected from the group consisting of compounds represented by Formulae (1-1) to (I- 10) below:) wherein in Formula (1-5) and (1-7), 1 and m each represents an integer of 1 to 30, in Formula (1-5), R represents Cl to C8 alkylene, and in Formulae (1-9) and (I- 10), nl to n6 each represents an integer of from 1 to 30.Embodiment 15. The curable composition according to any one of the preceding embodiments, wherein the cycloaliphatic epoxide comprises a compound represented by Formula (II):R" is a group resulting from elimination of a quantity of p hydroxyl groups ( — OH) from a structural formula of a p-hydric alcohol [R"(0H)P], and p and n each represents an integer from 1 to 50.Embodiment 16. The curable composition according to embodiment 15, wherein the p- hydric alcohol [R"(0H)P] includes at least one selected from the group consisting of polyhydric alcohols having Cl to Cl 5 carbon atoms and 2,2-bis(hydroxymethyl)-l -butanol.Embodiment 17. The curable composition according to embodiment 15 or 16 wherein p is an integer from 1 to 6, and n is an integer from 1 to 30.Embodiment 18. The curable composition according to any one of embodiments 15 to 17, when p is 2 or greater, n is the same or different to each other.Embodiment 19. The curable composition according to any one of embodiments 15 to 18 the compound represented by Formula (II) includes a l,2-epoxy-4-(2-oxiranyl)cyclohexane of 2, 2-bis(hy droxymethyl)- 1 -butanol.Embodiment 20. The curable composition according to any one of the preceding embodiments, wherein the curable composition comprises the cycloaliphatic epoxide of from 5 to 60 % by weight based on a total amount (100 % by weight) of the curable composition.Embodiment 21. The curable composition according to any one of the preceding embodiments, wherein the curable composition comprises the cycloaliphatic epoxide of from 10 to 55 % by weight based on the total amount (100 % by weight) of the curable composition.Embodiment 22. The curable composition according to any one of the preceding embodiments, wherein the curable composition comprises the cycloaliphatic epoxide of from 15 to 50 % by weight based on the total amount (100 % by weight) of the curable composition.Embodiment 23. The curable composition according to any one of the preceding embodiments, wherein the curing agent comprises an acid anhydride-based curing agent.Embodiment 24. The curable composition according to any one of the preceding embodiments, wherein the curing agent comprises at least one selected from the group consisting of methyltetrahydrophthalic anhydrides, methylhexahydrophthalic anhydrides, dodecenyl succinic anhydride, methyl endomethylene tetrahydrophthalic anhydride, phthalic anhydride,maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylcyclohexene dicarboxylic anhydride, pyromellitic anhydride, trimellitic anhydride, benzophenone tetracarboxylic anhydride, nadic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, 4-(4-methyl-3-pentenyl)tetrahydrophthalic anhydride, succinic anhydride, adipic anhydride, sebacic anhydride, dodecanedioic anhydride, methylcylohexene tetracarboxylic anhydride, vinyl ether-maleic anhydride copolymers, alkyl styrene-maleic anhydride copolymers, and combinations thereof.Embodiment 25. The curable composition according to embodiment 24, wherein the methyltetrahydrophthalic anhydrides comprise 4-methyltetrahydrophthalic anhydride or 3- methyltetrahydrophthalic anhydride.Embodiment 26. The curable composition according to embodiment 24, wherein the methylhexahydrophthalic anhydrides comprise 4-methylhexahydrophthalic anhydride or 3- methylhexahydrophthalic anhydride.Embodiment 27. The curable composition according to any one of the preceding embodiments, wherein the curing agent comprises a methylnadic anhydride.Embodiment 28. The curable composition according to any one of the preceding embodiments, wherein the curing agent comprises an acid anhydride that is liquid at 25° C.Embodiment 29. The curable composition according to any one of the preceding embodiments, wherein the curable composition comprises the curing agent of from 50 to 200 % by weight based on the total amount (100 % by weight) of the cycloaliphatic epoxide (A).Embodiment 30. The curable composition according to any one of the preceding embodiments, wherein the curable composition comprises the curing agent of from 80 to 150 % by weight based on the total amount (100 % by weight) of the cycloaliphatic epoxide (A).Embodiment 31. The curable composition according to any one of the preceding embodiments, wherein the curable composition comprises graphene in an amount of from 0.01 to 50 % by weight with respect to a total amount (100 % by weight) of the cycloaliphatic epoxide (A) and the curing agent (B).Embodiment 32. The curable composition according to any one of the preceding embodiments, wherein the curable composition comprises graphene in an amount of from 0.05 to40 % by weight with respect to a total amount (100 % by weight) of the cycloaliphatic epoxide (A) and the curing agent (B).Embodiment 33. The curable composition according to any one of the preceding embodiments, wherein the curable composition comprises graphene in an amount of from 0.1 to 30 % by weight with respect to a total amount (100 % by weight) of the cycloaliphatic epoxide (A) and the curing agent (B).Embodiment 34. The curable composition according to any one of the preceding embodiments, wherein the curable composition comprises graphene in an amount of from 0.1 to 20 % by weight with respect to a total amount (100 % by weight) of the cycloaliphatic epoxide (A) and the curing agent (B).Embodiment 35. The curable composition according to any one of the preceding embodiments, wherein the curable composition comprises graphene in an amount of from 5 to 20 % by weight with respect to a total amount (100 % by weight) of the cycloaliphatic epoxide (A) and the curing agent (B).Embodiment 36. The curable composition according to any one of the preceding embodiments, wherein the curable composition comprises graphene in an amount of from 10 to 15 % by weight with respect to a total amount (100 % by weight) of the cycloaliphatic epoxide (A) and the curing agent (B).Embodiment 37. The curable composition according to any one of the preceding embodiments, wherein graphene is the only toughening agent included in the curable composition.Embodiment 38. The curable composition according to any one of the preceding embodiments, further comprising silica.Embodiment 39. The curable composition according to embodiment 38, wherein the curable composition comprises silica in an amount of from 0.1 to 5 % by weight with respect to a total amount (100 % by weight) of the cycloaliphatic epoxide (A), the curing agent (B) and the graphene (C).Embodiment 40. The curable composition according to embodiment 38, wherein the curable composition comprises silica in an amount of from 0.3 to 3 % by weight with respect to atotal amount (100 % by weight) of the cycloaliphatic epoxide (A), the curing agent (B) and the graphene (C).Embodiment 41. The curable composition according to embodiment 38, wherein a weight ratio of graphene to silica is in a range from 1:99 to about 99:1.Embodiment 42. The curable composition according to embodiment 38, wherein a weight ratio of graphene to silica is in a range from 2:1 to 10: 1.Embodiment 43. The curable composition according to any one of the preceding embodiments, wherein the curable composition excludes filler.Embodiment 44. The curable composition according to any one of the preceding embodiments, further comprising a chain extender.Embodiment 45. The curable composition according to embodiment 44, wherein the chain extender comprises at least one selected from the group consisting of diol compounds, alkanolamines, diamines, alicyclic diamines, aromatic diamines, aliphatic diamines, and combinations thereof.Embodiment 46. The curable composition according to embodiment 45, wherein the diol compounds comprise alkane diols.Embodiment 47. The curable composition according to embodiment 46, wherein the alkane diols comprise ethylene glycol or 1,4-butanediol.Embodiment 48. The curable composition according to any one of embodiments 44 to 47, wherein the curable composition comprises the chain extender in an amount from 0.1 to 10 % by weight with respect to a total amount (100 by weight) of the cycloaliphatic epoxide and the curing agent.Embodiment 49. The curable composition according to any one of embodiments 44 to 47, wherein the curable composition comprises the chain extender in an amount from 0.3 to 5 % by weight with respect to a total amount (100 by weight) of the cycloaliphatic epoxide and the curing agent.Embodiment 50. The curable composition according to any one of embodiments 44 to 47, wherein the curable composition comprises the chain extender in an amount from 0.5 to 3 % byweight with respect to a total amount (100 by weight) of the cycloaliphatic epoxide and the curing agent.Embodiment 51. The curable composition according to any one of the preceding embodiments, further comprising a catalyst.Embodiment 52. The curable composition according to embodiment 51, wherein the catalyst comprises a curing accelerator.Embodiment 53. The curable composition according to embodiment 51 or 52, wherein the catalyst comprises at least one selected from the group consisting of: U-CAT 12XD™ (trade name, supplied by San-Apro Ltd.), U-CAT SA 506™, U-CAT SA 102™, U-CAT 5003 ™, U- CAT 18X™, TPP-K™, TPP-MK™ (Hokuko Chemical Co., Ltd.) and combinations thereof.Embodiment 54. The curable composition according to embodiment 51, wherein the catalyst comprises U-CAT 12XD™ (trade name, supplied by San-Apro Ltd.).Embodiment 55. The curable composition according to any one of the preceding embodiments, further comprising a dispersing agent.Embodiment 56. The curable composition according to embodiment 55, wherein the dispersing agent comprises inorganic compounds.Embodiment 57. The curable composition according to embodiment of 55 or 56, wherein the curable composition comprises the dispersing agent in an amount from 0.1 to 25 % by weight with respect to a total amount (100 by weight) of the cycloaliphatic epoxide and the curing agent.Embodiment 58. The curable composition according to embodiment of 55 or 56, wherein the curable composition comprises the dispersing agent in an amount from 1 to 20 % by weight with respect to a total amount (100 by weight) of the cycloaliphatic epoxide and the curing agent.Embodiment 59. The curable composition according to embodiment of 55 or 56, wherein the curable composition comprises the dispersing agent in an amount from 2 to 12 % by weight with respect to a total amount (100 by weight) of the cycloaliphatic epoxide and the curing agent.Embodiment 60. A cured product of the curable composition according to any one of the preceding embodiments.Embodiment 61. A molded article formed from the curable composition according to any one of embodiments 1-59 or the cured product according to embodiment 60.Embodiment 62. An article comprising the cured product according to embodiment 60.Embodiment 63. A method of producing a molded article comprising: ejecting the curable composition; curing the ejected curable composition; and forming a molded article from the curable composition according to any one of embodiments 1-59 or the cured product of embodiment 60.

Claims

CLAIMS1. A curable composition comprising: a cycloaliphatic epoxide; a curing agent; and graphene.

2. The curable composition according to claim 1, wherein the cycloaliphatic epoxide comprises a compound represented by Formula (I):Formula (I) wherein, in Formula (I),X is a single bond or a linkage group, and optionally substituents is bonded to one or more of carbon atoms constituting cyclohexane ring.

3. The curable composition according to claim 2, wherein in Formula (I), the linkage group comprises a divalent group.

4. The curable composition according to any one of the preceding claims, wherein the cycloaliphatic epoxide comprises 3, 4-epoxy cyclohexylmethyl 3’,4’- epoxy cyclohexanecarboxylate represented by Formula (1-1) below:

5. The curable composition according to any one of the preceding claims, wherein the cycloaliphatic epoxide comprises at least one selected from the group consisting of compounds represented by Formulae (1-1) to (I- 10) below:wherein in Formula (1-5) and (1-7), 1 and m each represents an integer of 1 to 30, in Formula (1-5), R represents Cl to C8 alkylene, and in Formulae (1-9) and (I- 10), nl to n6 each represents an integer of from 1 to 30.

6. The curable composition according to claim 1, wherein the cycloaliphatic epoxide comprises a compound represented by Formula (II):wherein, in Formula (II),R" is a group resulting from elimination of a quantity of p hydroxyl groups ( — OH) from a structural formula of a p-hydric alcohol [R"(0H)P], andp and n each represents an integer from 1 to 50.

7. The curable composition according to any one of the preceding claims, wherein the curable composition comprises the cycloaliphatic epoxide of from 5 to 60 % by weight based on the total amount (100 % by weight) of the curable composition.

8. The curable composition according to any one of the preceding claims, wherein the curing agent comprises an acid anhydride-based curing agent.

9. The curable composition according to any one of the preceding claims, wherein the curable composition comprises graphene in an amount of from 0.01 to 50 % by weight with respect to a total amount (100 % by weight) of the cycloaliphatic epoxide and the curing agent .

10. The curable composition according to any one of the preceding claims, further comprising silica.

11. The curable composition according to claim 10, wherein the curable composition comprises silica in an amount of from 0.1 to 5 % by weight with respect to a total amount (100 % by weight) of the of the cycloaliphatic epoxide, the curing agent and the graphene .

12. The curable composition according to any one of the preceding claims, further comprising a chain extender.

13. The curable composition according to any one of the preceding claims, further comprising dispersing agent.

14. A cured product of the curable composition according to any one of the preceding claims.

15. A molded article formed from the curable composition according to any one of claims 1- 13 or the cured product according to claim 14.

16. An article comprising the cured product according to claim 14.

17. A method of producing a molded article comprising: ejecting the curable composition; curing the ejected curable composition; and forming a molded article from the curable composition according to any one of claims 1 - 13 or the cured product of claim 14.

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