Epoxy resin composition

Abstract

[Topic] To provide an epoxy resin composition comprising an isocyanuric acid-type epoxy compound and a liquid epoxy compound, wherein the resin composition exhibits suppressed precipitation and excellent flowability during storage. [Solution] An epoxy resin composition comprising an epoxy compound A represented by formula [1] reacting with a L-piperidine derivative B to form a product C and a liquid epoxy compound D. (where R is in the formula) 1 to R 3 represents a hydrogen atom or a methyl group, respectively; L represents a hydrogen atom or a methyl group. 1 to L 3 (each independently represents an alkyl group having 1 to 10 carbon atoms).

Description

Technical Field

[0001] This invention relates to epoxy resin compositions. More specifically, it relates to an epoxy resin composition in which the precipitation of epoxy compounds contained therein is suppressed during storage. Prior Technology

[0002] Historically, epoxy compounds have been widely used as industrial raw materials in a wide range of fields such as adhesives, coatings, and electronic materials due to the excellent heat resistance, chemical resistance, high electrical insulation, and high adhesion of their cured products.

[0003] Triglycidyl isocyanate (trade name TEPIC (registered trademark)), as one of the isocyanuric acid type epoxy compounds, uses an isocyanuric acid backbone as its parent core and has three epoxy groups per molecule. Therefore, it is characterized by high reactivity, high crosslinking density of the resulting cured product, and the ability to obtain a product with a high glass transition temperature. Furthermore, because the backbone is a triazine ring, it exhibits excellent transparency, heat resistance, weather resistance, and lightfastness, as well as excellent electrical properties at high temperatures.

[0004] Generally, the aforementioned isocyanate-type epoxy compounds are solids. When considering liquid compositions requiring casting or molding, epoxy resin compositions obtained by combining them with various organic solvents or general-purpose liquid epoxy compounds are examined. Furthermore, to improve the solubility of the isocyanate-type epoxy compound in organic solvents or its compatibility with liquid epoxy compounds, and to improve the workability of the resin composition, the proposed composition contains a compound obtained by modifying the epoxy groups of the compound with anhydrides (Patent Documents 1-3). [Previous Technical Documents] [Patent Literature]

[0005] [Patent Document 1] International Publication No. 2006 / 035641 [Patent Document 2] International Publication No. 2018 / 074517 [Patent Document 3] Japanese Patent Application Publication No. 2013-209502 Summary of the Invention

[0006] [The problem that the invention aims to solve]

[0007] The resin composition obtained by combining the above-mentioned isocyanate-type epoxy compound with a liquid epoxy compound is prone to precipitation of the isocyanate-type epoxy compound during storage, resulting in an uneven composition and thus very poor workability. Furthermore, while modifying the epoxy groups of the isocyanate-type epoxy compound with an anhydride suppresses precipitation during storage, the resulting resin composition becomes highly viscous after formulation, which also leads to very poor workability.

[0008] The purpose of this invention is to provide an epoxy resin composition comprising an isocyanuric acid-type epoxy compound and a liquid epoxy compound, wherein the resin composition exhibits suppressed precipitation and excellent flowability during storage. [Methods for solving problems]

[0009] Through in-depth research, the inventors discovered that by incorporating a levopimaric acid derivative into an epoxy resin composition—specifically, by having it present in the epoxy resin composition as a reaction product of isocyanate-type epoxy compounds and the levopimaric acid derivative—the curing properties of the composition or the properties of the cured product are not adversely affected, the precipitation of epoxy compounds during storage is suppressed, and the flowability of the resin composition is excellent. Therefore, this invention is complete.

[0010] That is, the first aspect of the present invention relates to an epoxy resin composition comprising an epoxy compound A represented by formula [1] and a reaction product C of a L-pilocarboxylic acid derivative B, and a liquid epoxy compound D, wherein the L-pilocarboxylic acid derivative B is selected from at least one of the compounds represented by formulas [2-1] to [2-5]. (In the formula, R1 to R3 independently represent hydrogen atoms or methyl groups, and L1 to L3 independently represent alkyl groups with 1 to 10 carbon atoms.) (in the aforementioned formula, R4, R4', R5, R5', R6, R7, R8, and R8' each independently represent a straight-chain or branched alkyl group with 1 to 6 carbon atoms. R9, R9', R10, and R10' each independently represent a hydrogen atom, a straight-chain or branched alkyl group having 1 to 6 carbon atoms, -COOM, or R9 or R9' together with R10 or R10' to form an anhydride. M represents a hydrogen atom, an alkali metal atom, or an alkaline earth metal atom. The second viewpoint concerns the epoxy resin composition described in the first viewpoint, wherein the aforementioned reaction product C is a reaction product of the following mixture. The mixture is a mixture obtained by including 0.3 to 20 parts by mass of the aforementioned L-piperidine derivative B relative to 100 parts by mass of the total of the aforementioned epoxy compound A and epoxy compound D. The third viewpoint concerns the epoxy resin composition described in the first or second viewpoint, wherein the aforementioned L-pilocarboxylic acid derivative B is a compound selected from at least one of the compounds represented by the following formula. (In the formula, M' represents an alkali metal atom or an alkaline earth metal atom). The fourth viewpoint refers to the epoxy resin composition described in any of the first to third viewpoints, wherein the aforementioned epoxy compound D is an aromatic epoxy compound. The fifth point concerns the epoxy resin composition described in the fourth point, wherein the aforementioned aromatic epoxy compound is a difunctional aromatic epoxy compound D1. The sixth point concerns the epoxy resin composition described in the fifth point, wherein the aforementioned difunctional aromatic epoxy compound D1 is an epoxy compound having a bisphenol A backbone or a bisphenol F backbone. The seventh point refers to the epoxy resin composition described in any of the first to sixth points, wherein it further includes a curing agent E. The eighth point concerns the epoxy resin composition described in the seventh point, wherein the aforementioned curing agent E is selected from at least one of the group consisting of acid anhydrides, amines, phenolic resins, polyamide resins, imidazoles, polythiols (polymercaptan), and dicyanamide. The ninth point concerns an epoxy curing body, which is a cured product of the epoxy resin composition described in any of the first to eighth points. The tenth point relates to a method for manufacturing an epoxy resin composition, comprising the following steps: The step of stirring a mixture comprising an epoxy compound A represented by formula [1], a levorotatory pinoic acid derivative B selected from the group consisting of compounds represented by formulas [2-1] to [2-5], and a liquid epoxy compound D at a temperature exceeding 100°C but not exceeding 200°C. (In the formula, R1 to R3 independently represent hydrogen atoms or methyl groups, and L1 to L3 independently represent alkyl groups with 1 to 10 carbon atoms.) (in the aforementioned formula, R4, R4', R5, R5', R6, R7, R8, and R8' each independently represent a straight-chain or branched alkyl group with 1 to 6 carbon atoms. R9, R9', R10, and R10' each independently represent a hydrogen atom, a straight-chain or branched alkyl group having 1 to 6 carbon atoms, -COOM, or R9 or R9' together with R10 or R10' to form an anhydride. M represents a hydrogen atom, an alkali metal atom, or an alkaline earth metal atom. The 11th point concerns the method for manufacturing the epoxy resin composition described in the 10th point, which includes the following steps: The steps include further cooling the mixture to room temperature to below 100°C after the aforementioned stirring step, and adding the hardener E to the aforementioned mixture after cooling and stirring. The 12th point concerns a method for suppressing precipitation, which involves suppressing the precipitation of epoxy compound A in an epoxy resin composition comprising epoxy compound A represented by formula [1] and liquid epoxy compound D, characterized in that the epoxy resin composition comprises a reaction product C of L-pilocarboxylic acid derivative B and epoxy compound A, wherein the L-pilocarboxylic acid derivative B is selected from at least one of the compounds represented by formulas [2-1] to [2-5]. (In the formula, R1 to R3 independently represent hydrogen atoms or methyl groups, and L1 to L3 independently represent alkyl groups with 1 to 10 carbon atoms.) (in the aforementioned formula, R4, R4', R5, R5', R6, R7, R8, and R8' each independently represent a straight-chain or branched alkyl group with 1 to 6 carbon atoms. R9, R9', R10, and R10' each independently represent a hydrogen atom, a straight-chain or branched alkyl group having 1 to 6 carbon atoms, -COOM, or R9 or R9' together with R10 or R10' to form an anhydride. M represents a hydrogen atom, an alkali metal atom, or an alkaline earth metal atom. [The effects of the invention]

[0011] The present invention provides an epoxy resin composition in which the aforementioned isocyanate-type epoxy compound exists in the composition by means of a reaction product with a L-pilocarboxylic acid derivative, thereby suppressing precipitation during storage and providing excellent flowability. Implementation

[0012] [Optimal Form of Invention Implementation] [Epoxy Resin Composition]

[0013] The epoxy resin composition of the present invention comprises the reaction product C of epoxy compound A (hereinafter simply referred to as "epoxy compound A") represented by formula [1] and L-pilosic acid derivative B (hereinafter simply referred to as "L-pilosic acid derivative B") and liquid epoxy compound D, wherein the L-pilosic acid derivative B is selected from at least one of the compounds represented by formulas [2-1] to [2-5]. That is, the epoxy resin composition of the present invention only needs to include, in addition to the liquid epoxy compound D, the product C of the reaction between epoxy compound A and L-pilocarboxylic acid derivative B. In one embodiment, in addition to the liquid epoxy compound D, it also includes the following states: a state containing the product C of the reaction between epoxy compound A and L-pilocarboxylic acid derivative B; a state containing epoxy compound A and the product C of the reaction between epoxy compound A and L-pilocarboxylic acid derivative B; a state containing L-pilocarboxylic acid B and the product C of the reaction between epoxy compound A and L-pilocarboxylic acid derivative B; and a state containing epoxy compound A, L-pilocarboxylic acid derivative B and the product C of the reaction between epoxy compound A and L-pilocarboxylic acid derivative B.

[0014] [Epioxide compound A represented by formula [1]] The epoxy compound A used in this invention is represented by the following formula [1]. In the above formula [1], R1 to R3 represent hydrogen atoms or methyl groups, and L1 to L3 represent alkyl groups with 1 to 10 carbon atoms.

[0015] Examples of alkyl groups with 1 to 10 carbon atoms, represented by L1 to L3, include methylene, ethyl, trimethylene, 1-methylethyl, tetramethylene, 1-methyltrimethylene, 1,1-dimethylethyl, pentamethylene, 1-methyltetramethylene, 2-methyltetramethylene, 1,1-dimethyltrimethylene, 1,2-dimethyltrimethylene, 2,2-dimethyltrimethylene, 1-ethyltrimethylene, hexamethylene, 1-methylpentamethylene, and 2-methylpentamethylene. Methylene, 3-methylpentamethylene, 1,1-dimethyltetramethylene, 1,2-dimethyltetramethylene, 2,2-dimethyltetramethylene, 1-ethyltetramethylene, 1,1,2-trimethyltrimethylene, 1,2,2-trimethyltrimethylene, 1-ethyl-1-methyltrimethylene, 1-ethyl-2-methyltrimethylene, cyclohexane-1,4-diyl, heptamethyl, octamethyl, nonamethylene, 2-methyloctamethyl, decamethyl, etc. Methylene, trimethylene, and hexamethylene are preferred.

[0016] In this invention, the epoxy compound represented by formula [1] can be a commercially available epoxy compound or an epoxy compound containing a triisocyanate ring manufactured by a known method. Commercially available epoxy compounds may include, but are not limited to, TEPIC-G, TEPIC-S, TEPIC-SP, TEPIC-SS, TEPIC-HP [Nissan Chemical Co., Ltd., triglycidyl isocyanate]; tris(3,4-epoxybutyl) isocyanate; TEPIC-VL [Nissan Chemical Co., Ltd., tris(4,5-epoxypentyl) isocyanate]; tris(5,6-epoxyhexyl) isocyanate; TEPIC-FL [Nissan Chemical Co., Ltd., tris(7,8-epoxyoctyl) isocyanate].

[0017] [L-piperidine derivative B] The L-piperidine derivative B used in this invention is a compound selected from at least one of the groups of compounds represented by formulas [2-1] to [2-5]. In the above formulas [2-1] to [2-5], R4, R4', R5, R5', R6, R7, R8 and R8' independently represent hydrogen atoms, alkyl groups with 1 to 6 carbon atoms in straight or branched chains, and M represents hydrogen atoms, alkali metal atoms or alkaline earth metal atoms. Furthermore, in the above formulas [2-3] and [2-4], R9, R9', R10 and R10' independently represent hydrogen atoms, straight-chain or branched alkyl groups with 1 to 6 carbon atoms, -COOM, or R9 or R9' together with R10 or R10' to form an acid anhydride.

[0018] Examples of alkyl groups with 1 to 6 carbon atoms that are straight-chain or branched include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, and n-hexyl.

[0019] As specific examples of compounds represented by formulas [2-1] to [2-5] above, compounds represented by formulas [2-1a], [2-1b], [2-2a], [2-3a], [2-3b], [2-4a] or [2-5a] can be given. These compounds are resin acids and their derivatives that constitute rosin, also known as rosin acid (formula [2-1a]), rosin acid metal salt (formula [2-1b]), tetrahydrorosin acid (formula [2-2a]), acrylopimaric acid (formula [2-3a]), maleopimaric acid (formula [2-3b]), dihydroacryloimaric acid (formula [2-4a]), or L-piperidine (formula [2-5a]). (In the above formula, M' represents an alkali metal atom or an alkaline earth metal atom).

[0020] In this invention, the L-pilocarboxylic acid derivative B represented by formulas [2-1] to [2-5] can be a commercially available compound or a compound manufactured by a known method. As commercially available products, products and developments of L-piperidine derivatives or pinoresinic acid derivatives are available from Arakawa Chemical Industry Co., Ltd. and Harima Chemicals Group Co., Ltd.

[0021] [Reaction product C] The reaction product C in this invention is the reaction product of the epoxy compound A represented by the above formula [1] and at least one of the L-piperidine derivatives B selected from the group of compounds represented by the above formulas [2-1] to [2-5]. The reaction product C is an ester compound obtained by reacting one or all of the epoxy groups of the above-mentioned epoxy compound A with the L-piperidine derivative B. By reacting the epoxy compound A represented by the above formula [1] with the L-pilocarboxylic acid derivative B, compounds can be formed by adding 1 molecule of L-pilocarboxylic acid derivative B to epoxy compound A, 2 molecules of L-pilocarboxylic acid derivative B to epoxy compound A, and 3 molecules of L-pilocarboxylic acid derivative B to epoxy compound A. The amounts of these compounds can be adjusted in various ways by adjusting the reaction conditions or the molar number of L-pilocarboxylic acid derivative B relative to epoxy compound A. Unreacted epoxy compound (epoxide compound A) or unreacted L-pilocarboxylic acid derivative B may also be present in the reaction system. The above reaction product C can be obtained by, for example, by stirring a mixture comprising the epoxy compound A represented by the above formula [1], the above-mentioned L-piperidine derivative B, and the liquid epoxy compound D described below at a temperature exceeding 100°C but not exceeding 200°C.

[0022] In the epoxy resin composition of the present invention, the reaction product C can be set as the reaction product of the following mixture: the mixture contains, for example, 0.3 parts to 20 parts by mass, or for example, 1 parts to 15 parts by mass, the L-piperidine derivative B represented by formulas [2-1] to [2-5] relative to the total amount of epoxy compound (that is, the total of epoxy compound A represented by formula [1] and the liquid epoxy compound D described below) for 100 parts by mass.

[0023] [Liquid Epoxy Compound D] The epoxy resin composition of the present invention includes a liquid epoxy compound D. The liquid epoxy compound D dissolves the epoxy compound A represented by the above formula [1], improves the workability of the epoxy resin composition, and can also play a role in adjusting the physical properties such as the elastic modulus of the cured resin composition. The aforementioned liquid epoxy compound D can be any liquid epoxy compound among aliphatic, alicyclic, and aromatic epoxy compounds, and is not limited thereto. Among these, aromatic epoxy compounds are preferred, and a suitable example is a difunctional aromatic epoxy compound D1 having two epoxy groups. Among them, aromatic epoxy compound D1 is preferably an epoxy compound having a bisphenol A backbone or a bisphenol F backbone.

[0024] The aforementioned aromatic epoxy compounds can be used in commercially available products. Examples of difunctional aromatic epoxy compounds D1 include Mitsubishi Chemical Company's jER (registered trademark) 806, a bisphenol F type epoxy compound, and Mitsubishi Chemical Company's jER (registered trademark) 828, a bisphenol A type epoxy compound. Furthermore, examples of monofunctional aromatic epoxy compounds include phenyl glycidyl ethers (e.g., manufactured by Nagase ChemteX, Denacol EX-141, a registered trademark), phenol (EO)5 glycidyl ethers (e.g., manufactured by Nagase ChemteX, Denacol EX-145, a registered trademark), and p-tert-butylphenyl glycidyl ethers (e.g., manufactured by Nagase ChemteX, Denacol EX-146, a registered trademark).

[0025] Furthermore, as the aforementioned aliphatic or alicyclic epoxy compounds, examples include monofunctional or difunctional aliphatic or alicyclic epoxy compounds, which may be commercially available. For example, examples of the aforementioned monofunctional aliphatic epoxy compounds include ethylene oxide-2-ylmethyl 2-(4,4-dimethylpentan-2-yl)-5,7,7-trimethyloctanoate (Nissan Chemical Co., Ltd., FOLDI (registered trademark) E101); examples of the aforementioned difunctional aliphatic epoxy compounds include 2,2-bis(ethylene oxide-2-ylmethoxy)methyl)butyl 2-(4,4-dimethylpentan-2-yl)-5,7,7-trimethyloctanoate (Nissan Chemical Co., Ltd., FOLDI (registered trademark) E201), but are not limited to these. Commercially available examples of the aforementioned monofunctional alicyclic epoxy compounds include 3,4-epoxycyclohexyl methyl methacrylate (e.g., Daicel Corporation, Cyclomer (registered trademark) M-100), 3,4-epoxycyclohexyl methacrylate (e.g., Daicel Corporation, Cyclomer (registered trademark) A-200), 1,2-epoxy-4-vinylcyclohexane (e.g., Daicel Corporation, Celloxide (registered trademark) 2000), and 1,2,8,9-diepoxylimonene (e.g., Daicel Corporation, Celloxide (registered trademark) 3000), etc. Furthermore, examples of the aforementioned difunctional alicyclic epoxy compounds include, for instance, diepoxydicyclohexyl (e.g., manufactured by Daicel, Celloxide 8000 and Celloxide 8010), 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexene carboxylate (e.g., manufactured by Daicel, Celloxide 2021P), ε-caprolactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate (e.g., manufactured by Daicel, Celloxide 2081), bis(3,4-epoxycyclohexylmethyl) adipic acid ester, and diepoxylated tetrahydroindene (e.g., manufactured by ENEOS, EPOCHALIC THI-DE).

[0026] In the epoxy resin composition of the present invention, relative to 100 parts by mass of the total amount of epoxy compound (that is, the total of epoxy compound A and epoxy compound D), epoxy compound D can be included in a ratio of, for example, 5 parts by mass to 80 parts by mass, or, for example, 10 parts by mass to 70 parts by mass.

[0027] [Hardening Agent E] The epoxy resin composition of the present invention may further include a hardener E. The curing agent is not particularly limited, and can be, for example, acid anhydrides, amines, phenolic resins, polyamide resins, imidazoles, polythiols, or mixtures thereof. Among these, acid anhydrides and amines are particularly preferred. These hardeners can be solid or dissolved in a solvent. However, since the evaporation of the solvent can cause a decrease in the density of the hardened material, or the formation of pores can lead to a decrease in strength and water resistance, it is preferable that the hardener itself is liquid at room temperature and pressure. The curing agent can be contained in a ratio of 0.5 to 1.5 equivalents relative to the total amount of epoxy groups in the epoxy compound (i.e., the total epoxy compound consisting of epoxy compound A represented by formula [1] and liquid epoxy compound D). The curing agent equivalent relative to the epoxy compound is expressed as the equivalent ratio of the curing group of the curing agent to the epoxy group. Furthermore, if other epoxy compounds are used in addition to epoxy compound A represented by formula [1] and liquid epoxy compound D, the equivalent amount of epoxy groups in these total epoxy compounds will be within the range described above.

[0028] As an acid anhydride, it is preferred to be an anhydride of a compound having a plurality of carboxyl groups in one molecule. Examples of such acid anhydrides include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol dipremetyltrimethylbenzene, glycerol trimellitic trimethylbenzene, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylmethylenetetrahydrophthalic anhydride, methylmethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, methylcyclohexenedicarboxylic anhydride, chlorendic acid anhydride, etc. Of these, methyltetrahydrophthalic anhydride, methyl-5-norbornene-2,3-dicarboxylic anhydride (methylnadic anhydride, norbornene anhydride), hydrogenated methylnadic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, methylhexahydrophthalic anhydride, or a mixture of methylhexahydrophthalic anhydride and hexahydrophthalic anhydride, which are liquid at room temperature and pressure, are preferred. The viscosity of these liquid anhydrides, measured at 25°C, is approximately 10–1,000 mPa·s. In the anhydride group, one anhydride group is considered as one equivalent.

[0029] Examples of amines include piperidine, N,N'-dimethylpiperazine, triethylenediamine, 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, 2-(dimethylaminomethyl)phenol, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, di(1-methyl-2-aminocyclohexyl)methane, menthanediamine, isophoronediamine, diaminodicyclohexylmethane, 1,3-bis(aminomethyl)cyclohexane, succinic acid diamine, m-phenylenediamine, diaminodiphenylmethane, and diaminodiphenylamine. Among these, liquid forms of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, bis(1-methyl-2-aminocyclohexyl)methane, menthol diamine, isophorone diamine, diaminodicyclohexylmethane, etc., are preferred.

[0030] Examples of phenolic resins include phenolic varnish resin and cresol varnish resin.

[0031] Polyamide resin is formed by the condensation of dimer acid and polyamine, and the molecule contains both primary and secondary amines.

[0032] Examples of imidazole derivatives include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecapridinium trimellitic acid, and epoxy imidazole adducts.

[0033] Polythiols are those with thiol groups at the ends of polypropylene glycol chains or polyethylene glycol chains, preferably in liquid form.

[0034] Furthermore, dicyandiamide, a known latent curing agent, can also be used as curing agent E. Dicyandiamide is almost insoluble in epoxy resin at room temperature, but dissolves and reacts with the epoxy groups (curing) when heated above 180°C. Therefore, it is a latent curing agent with excellent storage stability at room temperature. If a lower curing temperature is desired, as described later, by using a urea-based or imidazole-based curing accelerator F, the curing temperature can be reduced to, for example, around 120-140°C. Moreover, dicyandiamide has the ability to maintain a semi-cured state for a certain period, and the cured product exhibits high heat resistance and high adhesion. Because dicyandiamine contains a catalytic functional group (-CN group) in its compound, it generally does not need to be stoichiometrically equivalent with epoxy groups; even a less than full equivalent can be used for curing.

[0035] [Hardening Accelerator F] In addition to the curing agent E mentioned above, the epoxy resin composition of the present invention may also appropriately contain a curing accelerator F (also known as a curing aid). Examples of curing accelerators include organophosphorus compounds such as triphenylphosphine and tributylphosphine; fourth-order phosphine salts such as ethyltriphenylphosphine bromide and tetrabutylphosphine O,O-diethylthiodiphosphate; and fourth-order ammonium salts such as 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,8-diazabicyclo[5.4.0]undec-7-ene salts with octanoic acid, zinc octanoate, and tetrabutylammonium bromide. Furthermore, imidazoles such as 2-methylimidazole and 2-ethyl-4-methylimidazole, or amines such as 2,4,6-tris(dimethylaminomethyl)phenol and benzyldimethylamine, can also be used as other types of curing accelerators for curing agents. Furthermore, if dicyandiamide (DICY) is used as a curing agent, urea derivatives such as phenyl dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), or the aforementioned imidazoles or amines can be used. The curing accelerator can be used at a ratio of 0.001 to 5 parts by mass relative to 1 part by mass of the curing agent.

[0036] The epoxy resin composition of this invention may also include a solvent as needed. The solvent is not particularly limited without impairing the effects of this invention; alcohols, ketones, ethers, and esters may be used. Examples of solvents mentioned above include, for example, alcohols such as methanol, ethanol, propanol, isopropanol, n-butanol, ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; ketones such as cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, γ-butyl lactone, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone; ethers such as butyl cellosolve; and esters such as ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, and propylene glycol monomethyl ether acetate, but are not limited to these.

[0037] [Other ingredients] The epoxy resin composition of this invention may also include conventional additives as needed. Examples of such additives include, for instance, curing catalysts (photoacid generators, thermal acid generators, alkali generators, etc.), curing monomers (cationic curing monomers such as vinyl compounds and oxygen-containing heterocyclic butyl compounds), thickeners, sensitizers, defoamers, leveling agents, coatability modifiers, lubricants, stabilizers (antioxidants, heat stabilizers, light stabilizers, etc.), plasticizers, surfactants (fluorinated surfactants, polysiloxane surfactants, nonionic surfactants, etc.), adhesion promoters, solubilizers, fillers, antistatic agents, and curing agents. These additives may be used alone or in combination of two or more.

[0038] [Manufacturing method of epoxy resin composition] The manufacturing method of the epoxy resin composition of the present invention is not particularly limited, but it is preferable to manufacture it by including the following steps: The step of stirring a mixture comprising an epoxy compound A represented by formula [1], a levorotatory pinoic acid derivative B selected from the group of compounds represented by formulas [2-1] to [2-5], and a liquid epoxy compound D at a temperature exceeding 100°C but not exceeding 200°C.

[0039] Furthermore, by including the step of cooling the mixture to room temperature to below 100°C after the above stirring step, and then adding the above-mentioned curing agent E to the mixture after cooling and stirring, an epoxy resin composition containing curing agent E can be manufactured. Additionally, a curing accelerator F may also be added when adding curing agent E. When adding curing agent E (and the desired curing accelerator F), a portion of liquid epoxy compound D can be separated during the previous stirring step of epoxy compound A and epoxy compound D, and the separated portion of liquid epoxy compound D can be mixed with curing agent E (and the desired curing accelerator F) and then added to the above mixture. It is best to mix and degas the mixture after adding hardener E (and the desired hardening accelerator F) under reduced pressure.

[0040] [Epoxy Cured Body] The epoxy resin composition of this invention can be cured by the following operation: applying the epoxy resin composition to a substrate or injecting it into a casting mold coated with a release agent, pre-curing at a temperature of, for example (as needed), 100-120°C, and then performing main curing (post-curing) at a temperature of 120-200°C. The heating time can be appropriately adjusted according to the size or thickness of the epoxy resin. For example, both pre-curing and main curing are 1-12 hours, for example, about 2-5 hours. The cured body, which is a cured product of the epoxy resin composition of the present invention, is also the subject of the present invention.

[0041] [Methods for inhibiting the precipitation of epoxide compound A] Furthermore, the method for precipitating epoxy compound A in an epoxy resin composition comprising epoxy compound A represented by the above formula [1] and liquid epoxy compound D is also the subject of this invention. The above-mentioned method for suppressing precipitation is characterized in that the epoxy resin composition exists in the form of a reaction product of the aforementioned isocyanuric acid type epoxy compound and a L-piperidine derivative, that is, it includes a reaction product C of at least one L-piperidine derivative B selected from the group of compounds represented by formulas [2-1] to [2-5] and the epoxy compound A. [Example]

[0042] The present invention will be described in more detail below with examples, but the present invention is not limited to the examples described below.

[0043] Furthermore, in the embodiments, the apparatus and conditions used for preparing the samples and analyzing their properties are as follows. (1) NMR Device: AVANCE III (600MHz) [Made by Bruker] Measurement conditions: 13C-NMR Deuterated solvent: DMSO-d 6 (2) Viscosity (rheometer) Device: MCR-302 [Made by Anton Paar] Measurement speed: 1 rpm; Measurement temperature: 70℃, 100℃ (3) Glass transition temperature Tg Apparatus: DMA Q800 dynamic viscoelasticity measuring device [manufactured by TA Instruments] Transformation Mode: Dual Cantilever Frequency: 1Hz Strain: 0.05% Scanning temperature: 30~300℃ Heating rate: 5℃ / minute (4) Bending strength, flexural modulus of elasticity, and flexural strength Equipment: Autograph AGS-5kNX benchtop precision universal testing machine [manufactured by Shimadzu Corporation] Measurements were taken according to JIS K-6911. (4-1) Bending strength Measure the height (thickness) and width of the specimen, support the specimen, and apply a load to the center of the specimen with a pressure wedge. Measure the load at which the specimen breaks. When P: load at which the specimen breaks (N) {kgf}, L: distance between support points (mm), W: width of the specimen (mm), and h: height of the specimen (mm), calculate the bending strength σ (MPa) {kgf / mm²} according to the following formula. Bending strength σ = (3PL) / (2Wh 2) (4-2) Flexural modulus When F / Y represents the slope of the straight portion of the load-bending curve (N / mm) {kgf / mm}, the flexural modulus of elasticity (E) is calculated using the following formula: (MPa){kgf / mm²} Flexural modulus E = [L³ / (4Wh³)] × [F / Y]

[0044] Furthermore, the codes for the components used in the embodiments are as follows. TEPIC-S: Triglycidyl isocyanate [Made by Nissan Chemical Co., Ltd., Trade Name: TEPIC (Registered Trademark)-S, Epoxy Equivalent: 100g / eq.] jER828: Bisphenol A type epoxy resin [Made by Mitsubishi Chemical Co., Ltd., jER (registered trademark) 828, epoxy equivalent: 185g / eq.] Ad-1: Pinoresinic acid [manufactured by Tokyo Chemical Industry Co., Ltd., (purity >80.0%)] Ad-2: Hydrogenated propylene rosin [Contains 30-50% by mass of dihydropropylene rosinic acid as represented by formula (2-4a), acid value: 239.6 mg KOH / g, manufactured by Arakawa Chemical Industry Co., Ltd.] Ad-3: Terephthalic acid [manufactured by Tokyo Chemical Industry Co., Ltd.] MH-700: RIKACID (registered trademark) MH-700 [Manufactured by Shin Nippon Rikka Co., Ltd., a mixture of 4-methylcyclohexane-1,2-dicarboxylic anhydride and cyclohexane-1,2-dicarboxylic anhydride, anhydride equivalent: 165 g / eq.] Ad-4: Acrylic acid modified rosin [Contains 60-70% by mass of acrylonitrile as represented by formula (2-3a), acid value: 247.1 mg KOH / g, manufactured by Arakawa Chemical Industry Co., Ltd.] Ad-5: 1,4-Cyclohexanedicarboxylic acid [manufactured by Tokyo Chemical Industry Co., Ltd.] PX-4ET: Tetrabutylphosphonium o,o-diethylthiobisphosphate [Manufactured by Nippon Kagaku Kogyo Co., Ltd., Hishicolin (registered trademark) PX-4ET] DICY: Dicyandiamine [Made by Mitsubishi Chemical Co., Ltd., jERCURE (registered trademark) DICY7] DCMU: 3-(3,4-Dichlorophenyl)-1,1-Dimethylurea [Manufactured by Tokyo Chemical Industry Co., Ltd.] MEK: Methyl ethyl ketone [Manufactured by Kanto Chemical Co., Ltd.] PGMEA: Propylene glycol monomethyl ether acetate [Manufactured by Kanto Chemical Co., Ltd.]

[0045] [Preparation of Epoxy Resin Composition] (Example 1) 10g of TEPIC-S, 9g of jER828, and 1g of Ad-1 were added to a container and heated and mixed at 150°C for 1 hour to obtain the epoxy resin composition of Example 1.

[0046] (Examples 2-12, Examples 24-29, Comparative Examples 1-10) Except for changing the formulation and dosage as shown in Table 1, the epoxy resin compositions of the examples and comparative examples were obtained by the same steps as in Example 1. In addition, in Comparative Examples 7 and 8, which were prepared with Ad-3, the heating conditions during preparation were set to 160°C for 3 hours, and in Comparative Examples 9 and 10, which were prepared with Ad-5, the heating conditions were set to 160°C for 2 hours. Furthermore, in the following explanation, the number examples of epoxy resin components are set as examples of numbers for performance evaluation or physical property evaluation.

[0047] In the epoxy resin composition of Example 6, the formation of reaction product C was confirmed by the following method. 13C-NMR spectra of TEPIC-S (epoxide A), Ad-2 (L-pimolic acid derivative B), jER828 (liquid epoxy D), the resin composition of Example 6, and the resin composition of Comparative Example 1 were measured to compare the peak intensities before and after the reaction. The results showed that the peak from the carboxyl group of Ad-2 (176-180 ppm) disappeared, and a new peak was observed at the high magnetic field side (174-178 ppm) for the ester bond associated with the reaction between the carboxyl group of Ad-2 and the epoxy group of TEPIC-S. Therefore, it was confirmed that TEPIC-S (epoxide A) reacted with Ad-2 (L-pimolic acid derivative B) to generate reaction product C. The resin compositions of other examples were also confirmed using the same method.

[0048] [Performance Evaluation of Epoxy Resin Components] (1) Presence or absence of crystallization The epoxy resin compositions of Examples 1-12, Examples 24-29, and Comparative Examples 1-10 were placed in glass containers and sealed. After being left at room temperature for one week, the presence or absence of crystal precipitation was observed visually. The evaluation was conducted based on the following evaluation criteria. The results are presented in Table 1. <Evaluation Criteria> A: No crystals precipitated; N: Crystals precipitated.

[0049] (2) Viscosity measurement of epoxy resin composition The viscosity of the epoxy resin compositions of Examples 1-4, Examples 24-25, and Comparative Examples 1, 7-10 was measured at 70°C and 100°C. The results are presented in Table 1.

[0050]

[0051] As shown in Table 1, it can be seen that the epoxy resin compositions of Examples 1 to 12 and Examples 24 to 29, which are prepared by Ad-1, Ad-2 or Ad-4, did not show any crystal precipitation after being placed at room temperature for 1 week. On the other hand, the epoxy resin compositions of Comparative Examples 1 to 6, which were not prepared using Ad-1, Ad-2 or Ad-4, showed crystal precipitation after being left at room temperature for 1 week, confirming that they lacked storage stability.

[0052] Furthermore, compared to the epoxy resin composition of Comparative Example 1 without Ad-1, Ad-2, or Ad-4, although an increase in viscosity can be observed in the epoxy resin compositions of Examples 1 to 4 and Examples 24 to 25, the viscosity at 70°C is approximately 1,000 mPa·s or less, and the viscosity at 100°C is approximately 130 mPa·s or less, which is considered low viscosity. Therefore, it is confirmed that the flowability of these compositions is excellent. On the other hand, the epoxy resin compositions of Comparative Examples 7 and 8, which were prepared by replacing Ad-1, Ad-2, or Ad-4 and containing Ad-3 (terephthalic acid), and the epoxy resin compositions of Comparative Examples 9 and 10, which were prepared by containing Ad-5 (1,4-cyclohexanedicarboxylic acid), did not show any crystal precipitation after being left at room temperature for one week. However, compared with the epoxy resin compositions of the examples prepared by formulating the same grade of components, their viscosity at 70°C and 100°C was higher (Comparative Examples 7 and 9 compared to Examples 1, 2, or 25; Comparative Examples 8 and 10 compared to Examples 3, 4, or 24). Therefore, the workability of the resin compositions was lacking.

[0053] [Current Properties of Epoxy Resin Compositions 1 (Current Agents: MH-700, PX-4ET)] (Example 13) 10.5g of TEPIC-S, 9.45g of jER828, and 1.05g of Ad-1 were added to a container and heated and mixed at 150°C for 1 hour, then cooled to 70°C. Next, 25.575g of MH-700 (epoxy equivalent ratio: 1 equivalent) as a hardener and 0.210g of PX-4ET as a curing accelerator were added. The mixture was stirred at 70°C for 30 minutes while undergoing degassing under reduced pressure to obtain the epoxy resin composition.

[0054] (Examples 14-20, Reference Examples 1-5) Except for changing the formulation and dosage as shown in Table 2, the epoxy resin compositions of each embodiment and reference example are obtained by the same steps as in Example 13. In addition, in Reference Examples 1 and 3 for preparing Ad-3, the conditions for heating and mixing TEPIC-S, jER828 and Ad-3 were set to 160°C for 3 hours.

[0055] Each component, along with a 3mm thick U-shaped polysiloxane spacer, is sandwiched between two glass substrates that have been pre-molded using OPTOOL (registered trademark) DSX [manufactured by Daikin Industries, Ltd.]. The substrate is heated to 100°C for 2 hours (pre-curing), then heated to 150°C for 5 hours (main curing). After cooling, the glass substrates are removed, resulting in each cured component with a 3mm thickness. The obtained hardened material was evaluated for glass transition temperature, flexural strength (stress), flexural modulus, and flexural deflection. Furthermore, the values ​​of each property were measured using the following steps. The results are presented in Table 2.

[0056] [Glass transition temperature (Tg)] The storage elastic modulus E' and loss elastic modulus E” are measured by DMA, and the temperature at which the maximum value of tanδ (loss elastic modulus E” / storage elastic modulus E') obtained from these measurements is set as Tg.

[0057] [Bending strength (stress), flexural modulus of elasticity, deflection] Measurements were performed in accordance with JIS K-6911:2006. Specifically, the specimen (80×10×3mm) was supported with a fulcrum distance of 64mm. A load was applied to the center of the specimen using a pressure wedge, and the slope F / Y [N / mm] of the straight section of the load-deflection curve was obtained. Furthermore, the load P [N] at which the specimen broke was determined. The flexural modulus is calculated using the following formula, taking the values ​​of the distance L [mm] between the support point, the width W [mm] of the specimen, and the thickness h [mm] of the specimen. Flexural modulus [MPa] = (L³ ÷ 4Wh³) × (F / Y) Bending strength (stress) [MPa] = 3PL ÷ 2Wh 2 Furthermore, the deflection (indentation distance) at the fracture point is evaluated as [deflection].

[0058]

[0059] [Curing Properties of Epoxy Resin Compositions 2 (Curing Agents: DICY, DCMU)] (Example 21) 13.5 g of TEPIC-S, 9.45 g (30% by mass of jER828 used), and 2.25 g of Ad-2 were added to a container and heated and mixed at 150°C for 1 hour, then cooled to 70°C. Next, a mixture previously treated with a three-roll mill (22.05 g (70% by mass of jER828 used), 1.35 g of DICY, and 1.35 g of DCMU) was added. While stirring at 70°C for 30 minutes, the mixture was degassed under reduced pressure to obtain the epoxy resin composition.

[0060] (Examples 22-23, Reference Examples 6-8) Except for changing the formulation and dosage as shown in Table 3, the hardened products of each embodiment and reference example are obtained by the same steps as in Example 21.

[0061] Each component, along with a 3mm thick U-shaped polysiloxane spacer, is sandwiched between two glass substrates that have been pre-molded using OPTOOL (registered trademark) DSX [manufactured by Daikin Industries, Ltd.]. The substrates are heated to 130°C for 2 hours (hardening), and after slow cooling, the glass substrates are removed, resulting in each hardened component with a thickness of 3mm. Following the same steps as in Examples 14 to 20 and Reference Examples 1 to 5, the obtained hardened material was evaluated for glass transfer temperature, flexural strength (stress), flexural modulus, and flexural deflection. The results are presented in Table 3.

[0062]

[0063] As shown in Table 2, the cured epoxy resin compositions formulated using Ad-1 or Ad-2 exhibit the same level of glass transition temperature, flexural strength (stress), flexural modulus, and flexural strength as those formulated using Ad-3 or without Ad-1 to Ad-3. Furthermore, as shown in Table 3, even when the type of hardener is changed, the epoxy resin composition prepared using Ad-2 exhibits the same level of hardener properties as the epoxy resin composition prepared without Ad-2.

[0064] [Solvent Solubility Evaluation of Epoxy Resin Components] (Epoxy Resin Composition A) 10g of TEPIC-S, 10g of jER828, and 2g of Ad-2 were added to a container and heated at 150°C for 1 hour to obtain epoxy resin composition A. (Epoxy Resin Composition B) Add 10g of TEPIC-S and 10g of jER828 to a container and heat and mix at 150°C for 1 hour to obtain epoxy resin composition B.

[0065] (Example 30) 1g of epoxy resin composition A and 9g of solvent MEK were placed in a glass container and mixed. The solubility of the epoxy resin composition in the solvent was observed visually, as well as the presence or absence of crystal precipitation after being left at room temperature for 2 weeks. The evaluation was conducted based on the following evaluation criteria. The results are presented in Table 4. <Evaluation Criteria> A: It dissolved uniformly, and no crystals precipitated after 2 weeks. B: Dissolves uniformly, but crystals will precipitate within one week. C: Not uniformly dissolved (insoluble)

[0066] (Examples 31-33) Except for changing the formulation and dosage as shown in Table 4, the solvent solubility was evaluated using the same steps as in Example 30.

[0067] (Comparative Examples 11 to 14) Except for changing the formulation and dosage as shown in Table 5, the solvent solubility was evaluated using the same steps as in Example 30.

[0068]

[0069]

[0070] As can be seen from Examples 30 to 33 in Table 4, the epoxy resin composition A prepared using Ad-2 is uniformly dissolved in MEK and PGMEA, and the precipitation of crystals at room temperature is suppressed. On the other hand, as can be seen from Comparative Examples 11-14 in Table 5, when MEK is used as a solvent, the epoxy resin composition B prepared without Ad-2 dissolves uniformly, but crystallization is confirmed to occur when placed at room temperature; when PGMEA is used as a solvent, the composition does not dissolve.

[0071] As can be confirmed from Tables 1 to 5 above, the epoxy resin composition of the present invention does not adversely affect the curability or curing properties of the composition, inhibits the precipitation of epoxy compounds during storage, and has excellent flowability.

Claims

1. An epoxy resin composition comprising an epoxy compound A represented by formula [1] reacting with a L-pilocarboxylic acid derivative B to form a product C and a liquid epoxy compound D, wherein, The L-piperidine derivative B is selected from at least one of the groups consisting of compounds represented by formulas [2-1], [2-3], [2-4], and [2-5], (where R1 to R3 independently represent a hydrogen atom or a methyl group, and L1 to L3 independently represent an alkyl group having 1 to 10 carbon atoms) (where R4, R4', R5, R5', R6, R7, R8, and R8' independently represent a hydrogen atom, a straight-chain or branched alkyl group having 1 to 6 carbon atoms, R9, R9', R10, and R10' independently represent a hydrogen atom, a straight-chain or branched alkyl group having 1 to 6 carbon atoms, -COOM, or R9 or R9' together with R10 or R10' to form an anhydride). M represents a hydrogen atom, an alkali metal atom, or an alkaline earth metal atom. However, excluding compounds in formula [2-1] where R4 represents isopropyl, R5 represents a hydrogen atom, R5' represents a hydrogen atom, R6 represents methyl, R7 represents methyl, R8 represents a hydrogen atom, and M represents a hydrogen atom.

2. The epoxy resin composition as claimed in claim 1, wherein, The aforementioned reaction product C is a reaction product of the following mixture, wherein the mixture is a mixture containing 0.3 to 20 parts by mass of the aforementioned L-piperidine derivative B relative to 100 parts by mass of the total of the aforementioned epoxy compound A and epoxy compound D.

3. The epoxy resin composition as claimed in claim 1 or claim 2, wherein, The aforementioned L-piperidine derivative B is a compound selected from at least one of the compounds represented by the following formula (where M' represents an alkali metal atom or an alkaline earth metal atom).

4. The epoxy resin composition as claimed in claim 1 or claim 2, wherein, The aforementioned epoxy compounds are D-series aromatic epoxy compounds.

5. The epoxy resin composition as claimed in claim 4, wherein, The aforementioned aromatic epoxy compound is a difunctional aromatic epoxy compound D1.

6. The epoxy resin composition as claimed in claim 5, wherein, The aforementioned difunctional aromatic epoxy compound D1 is an epoxy compound with a bisphenol A backbone or a bisphenol F backbone.

7. The epoxy resin composition as claimed in claim 1 or claim 2, wherein, It further contains hardener E.

8. The epoxy resin composition as claimed in claim 7, wherein, The aforementioned curing agent E is selected from at least one of the group consisting of acid anhydrides, amines, phenolic resins, polyamide resins, imidazoles, polythiols, and dicyandiamide.

9. An epoxy curable body, which is a cured product of the epoxy resin composition of any one of claims 1 to 8.

10. A method for manufacturing an epoxy resin composition, comprising the following steps: stirring a mixture comprising an epoxy compound A represented by formula [1], a levorotatory pinoic acid derivative B selected from the group consisting of compounds represented by formulas [2-1], [2-3], [2-4] and [2-5], and a liquid epoxy compound D at a temperature exceeding 100°C but not exceeding 200°C, (wherein R1 to R3 independently represent hydrogen atoms or methyl groups, and L1 to L3 independently represent alkyl groups having 1 to 10 carbon atoms) (wherein in the aforementioned formulas, R4, R4', R5, R5', R6, R7, R8 and R8' independently represent hydrogen atoms and straight-chain or branched alkyl groups having 1 to 6 carbon atoms, respectively). R9, R9', R10, and R10' each independently represent a hydrogen atom, a straight-chain or branched alkyl group having 1 to 6 carbon atoms, -COOM, or R9 or R9' together with R10 or R10' forming an anhydride. M represents a hydrogen atom, an alkali metal atom, or an alkaline earth metal atom. However, excluding the aforementioned formula [2-1], R4 represents isopropyl, R5 represents a hydrogen atom, R5' represents a hydrogen atom, R6 represents a methyl group, R7 represents a methyl group, R8 represents a hydrogen atom, and M represents a hydrogen atom in the compound.

11. A method for manufacturing the epoxy resin composition as claimed in claim 10, wherein, The process includes the following steps: further cooling the mixture to room temperature to below 100°C after the aforementioned stirring step; and adding the hardener E to the aforementioned mixture after cooling and stirring.

12. A method for suppressing precipitation, comprising suppressing the precipitation of epoxy compound A in an epoxy resin composition comprising epoxy compound A represented by the following formula [1] and liquid epoxy compound D, characterized in that the epoxy resin composition comprises a reaction product C of L-pilosolic acid derivative B and the aforementioned epoxy compound A, wherein, The L-piperidine derivative B is selected from at least one of the groups consisting of compounds represented by formulas [2-1], [2-3], [2-4] and [2-5] below, (where R1 to R3 independently represent a hydrogen atom or a methyl group, and L1 to L3 independently represent an alkyl group having 1 to 10 carbon atoms) (where R4, R4', R5, R5', R6, R7, R8 and R8' independently represent a hydrogen atom, a straight-chain or branched alkyl group having 1 to 6 carbon atoms, R9, R9', R10 and R10' independently represent a hydrogen atom, a straight-chain or branched alkyl group having 1 to 6 carbon atoms, -COOM, or R9 or R9' together with R10 or R10' to form an anhydride). M represents a hydrogen atom, an alkali metal atom, or an alkaline earth metal atom. However, excluding compounds in formula [2-1] where R4 represents isopropyl, R5 represents a hydrogen atom, R5' represents a hydrogen atom, R6 represents methyl, R7 represents methyl, R8 represents a hydrogen atom, and M represents a hydrogen atom.