epoxy resin composition

Abstract

[Problem] To provide an epoxy resin composition which contains an isocyanuric acid type epoxy compound and a liquid epoxy compound and which enables suppression of precipitation during storage and also has excellent flowability. [Solution] An epoxy resin composition comprising a liquid epoxy compound D and a reaction product C of an epoxy compound A represented by formula [1] and a levopimaric acid derivative B. [1] (In the formula, R1 to R3 each independently represent a hydrogen atom or a methyl group and L1 to L3 each independently represent a C1-10 alkylene group.)

Description

Technical Field

[0001] The present invention relates to an epoxy resin composition. More specifically, the present invention relates to an epoxy resin composition in which precipitation of an epoxy compound contained in the resin composition during storage is suppressed. Background Art

[0002] Conventionally, epoxy compounds have been used as industrial materials in a wide range of fields such as adhesives, paints, and electronic materials because cured products thereof have excellent heat resistance, chemical resistance, high electrical insulation, and high adhesiveness.

[0003] Triglycidyl isocyanurate (trade name TEPIC (registered trademark)), which is one of isocyanuric acid-type epoxy compounds, has an isocyanuric acid skeleton as a mother nucleus and has three epoxy groups in one molecule, so it has high reactivity, and the resulting cured product is characterized by having a high crosslinking density and a high glass transition temperature. Further, since the skeleton is a triazine ring, the compound is characterized by being excellent in transparency, heat resistance, weather resistance, and light resistance, and excellent in electrical properties at high temperatures.

[0004] The above isocyanuric acid-type epoxy compounds are generally solid, and when a liquid composition form such as casting molding is required, epoxy resin compositions in combination with various organic solvents and general-purpose liquid epoxy compounds have been studied. Furthermore, in order to improve the solubility of isocyanuric acid-type epoxy compounds in organic solvents and the compatibility with liquid epoxy compounds, and to improve the handling properties of the resin composition, compositions containing a compound obtained by modifying the epoxy groups of the compound with an acid anhydride have been proposed (Patent Documents 1 to 3). Prior Art Documents Patent Documents

[0005] Patent Document 1 International Publication No. 2006 / 035641 Patent Document 2 International Publication No. 2018 / 074517 [Patent Document 3] Japanese Patent Publication No. 2013-209502 [Overview of the project] [Problems that the invention aims to solve]

[0006] The resin composition combining the above-mentioned isocyanuric acid type epoxy compound and liquid epoxy compound suffers from poor handling properties because the isocyanuric acid type epoxy compound easily precipitates during storage, resulting in a non-uniform composition. Furthermore, while modifying the epoxy groups of the isocyanuric acid type epoxy compound with an acid anhydride suppresses precipitation during storage when combining the modified product with the liquid epoxy compound, the resulting resin composition becomes highly viscous after preparation, which also has the disadvantage of being very difficult to handle.

[0007] The present invention aims to provide an epoxy resin composition comprising an isocyanuric acid type epoxy compound and a liquid epoxy compound that exhibits suppressed precipitation during storage and excellent fluidity. [Means for solving the problem]

[0008] The present inventors conducted diligent research to solve the above problems and, as a result, discovered that by incorporating a levopimaric acid derivative into an epoxy resin composition, and more specifically by including an isocyanuric acid type epoxy compound as a reaction product with the levopimaric acid derivative, the precipitation of the epoxy compound during storage is suppressed without adversely affecting the curability or cured product properties of the composition, and the resin composition exhibits excellent fluidity, thus completing the present invention.

[0009] In other words, the present invention relates, in first aspect, to an epoxy resin composition comprising an epoxy compound A represented by formula [1], a reaction product C of at least one levopimaric acid derivative B selected from the group consisting of compounds represented by formulas [2-1] to [2-5], and a liquid epoxy compound D. [ka] (wherein R 1 to R 3 each independently represent a hydrogen atom or a methyl group, and L 1 to L 3 each independently represent an alkylene group having 1 to 10 carbon atoms.)

Chemical Formula

Chemical Formula

[0010] According to the present invention, in an epoxy resin composition comprising an isocyanuric acid type epoxy compound and a liquid epoxy compound, by including the isocyanuric acid type epoxy compound as a reaction product with a levopimaric acid derivative, it is possible to provide a resin composition that suppresses precipitation during storage and has excellent fluidity. [Modes for carrying out the invention]

[0011] [Epoxy resin composition] The epoxy resin composition of the present invention comprises a reaction product C of epoxy compound A represented by formula [1] (hereinafter also simply referred to as epoxy compound A) and at least one levopimaric acid derivative B selected from the group consisting of compounds represented by formulas [2-1] to [2-5] (hereinafter also simply referred to as levopimaric acid derivative B), and a liquid epoxy compound D. In other words, the epoxy resin composition of the present invention may be configured to include, in addition to a liquid epoxy compound D, a reaction product C of epoxy compound A and levopimaric acid derivative B as an essential component. One embodiment includes configurations comprising: liquid epoxy compound D and a reaction product C of epoxy compound A and levopimaric acid derivative B; epoxy compound A and a reaction product C of epoxy compound A and levopimaric acid derivative B; levopimaric acid B and a reaction product C of epoxy compound A and levopimaric acid derivative B; and epoxy compound A, levopimaric acid derivative B, and a reaction product C of epoxy compound A and levopimaric acid derivative B.

[0012] [Epoxy compound A represented by formula [1]] The epoxy compound A used in this invention is represented by the following formula [1]. [ka] In the above formula [1], R 1 ~R 3 Each of these independently represents a hydrogen atom or a methyl group, L 1 ~L 3 Each of these independently represents an alkylene group having 1 to 10 carbon atoms.

[0013] L 1 ~L 3Examples of alkylene groups with 1 to 10 carbon atoms represented by include methylene group, ethylene group, trimethylene group, 1-methylethylene group, tetramethylene group, 1-methyltrimethylene group, 1,1-dimethylethylene group, pentamethylene group, 1-methyltetramethylene group, 2-methyltetramethylene group, 1,1-dimethyltrimethylene group, 1,2-dimethyltrimethylene group, 2,2-dimethyltrimethylene group, 1-ethyltrimethylene group, hexamethylene group, 1-methylpentamethylene group, and 2-methylpentamethylene. Examples include the methylene group, 3-methylpentamethylene group, 1,1-dimethyltetramethylene group, 1,2-dimethyltetramethylene group, 2,2-dimethyltetramethylene group, 1-ethyltetramethylene group, 1,1,2-trimethyltrimethylene group, 1,2,2-trimethyltrimethylene group, 1-ethyl-1-methyltrimethylene group, 1-ethyl-2-methyltrimethylene group, cyclohexane-1,4-diyl group, heptamethylene group, octamethylene group, nonamethylene group, 2-methyloctamethylene group, decamethylene group, etc. Preferably, the methylene group, trimethylene group, or hexamethylene group.

[0014] In the present invention, the epoxy compound represented by formula [1] can be a commercially available epoxy compound or an isocyanurate ring-containing epoxy compound produced by a known method. Examples of commercially available epoxy compounds that can be used include, but are not limited to, TEPIC(registered trademark)-G, TEPIC(registered trademark)-S, TEPIC(registered trademark)-SP, TEPIC(registered trademark)-SS, and TEPIC(registered trademark)-HP [manufactured by Nissan Chemical Corporation, triglycidyl isocyanurate]; tris(3,4-epoxybutyl) isocyanurate; TEPIC(registered trademark)-VL(registered trademark) [manufactured by Nissan Chemical Corporation, tris(4,5-epoxypentyl) isocyanurate]; tris(5,6-epoxyhexyl) isocyanurate; and TEPIC(registered trademark)-FL(registered trademark) [manufactured by Nissan Chemical Corporation, tris(7,8-epoxyoctyl) isocyanurate].

[0015] [Levopimalate derivative B] The levopimaric acid derivative B used in the present invention is at least one compound selected from the group consisting of compounds represented by the following formulas [2-1] to [2-5]. [ka] In equations [2-1] to [2-5] above, R 4 , R 4’ , R 5 , R 5’ , R 6 , R 7 , R 8 , and R 8’ Each of these independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, while M represents a hydrogen atom, an alkali metal atom, or an alkaline earth metal atom. Also, in equations [2-3] and [2-4] above, R 9 , R 9’ , R 10 , and R 10’ Each of these independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, -COOM, or R 9 or R 9’ and R 10 or R 10’ They combine to form acid anhydrides.

[0016] Examples of linear or branched alkyl groups having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, neopentyl group, and n-hexyl group.

[0017] Specific examples of compounds represented by the above formulas [2-1] to [2-5] include the compounds represented by the following formulas [2-1a], [2-1b], [2-2a], [2-3a], [2-3b], [2-4a], or [2-5a]. These compounds are resin acids and their derivatives that constitute rosin, and are also called abietic acid (formula [2-1a]), metal abietic acid salt (formula [2-1b]), tetrahydroabietic acid (formula [2-2a]), acrylopimaric acid (formula [2-3a]), maleopimaric acid (formula [2-3b]), dihydroacrylopimaric acid (formula [2-4a]), or levopimaric acid (formula [2-5a]). [ka] (In the above formula, M' represents an alkali metal atom or an alkaline earth metal atom.)

[0018] In the present invention, the levopimaric acid derivative B represented by formulas [2-1] to [2-5] can be a commercially available product or a compound produced by known methods. Commercially available products and development materials containing levopimaric acid derivatives or abietic acid derivatives can be obtained from Arakawa Chemical Industries, Ltd. and Harima Chemicals Group Co., Ltd.

[0019] [Reaction product C] In the present invention, reaction product C is the reaction product of epoxy compound A represented by formula [1] and at least one levopimaric acid derivative B selected from the group consisting of compounds represented by formulas [2-1] to [2-5]. The reaction product C is an ester compound obtained by reacting some or all of the epoxy groups of the epoxy compound A with the levopimaric acid derivative B. The reaction of epoxy compound A represented by the above formula [1] with levopimaric acid derivative B can produce compounds in which one molecule of levopimaric acid derivative B is added to epoxy compound A, compounds in which two molecules of levopimaric acid derivative B are added, and compounds in which three molecules of levopimaric acid derivative B are added. The amounts of these compounds can be adjusted in various ways by adjusting the reaction conditions and the number of moles of levopimaric acid derivative B reacted with the number of moles of epoxy compound A. Unreacted epoxy compound (epoxy compound A) and unreacted levopimaric acid derivative B may be present in the reaction system. The above reaction product C is obtained, for example, by stirring a mixture containing epoxy compound A represented by formula [1] above, levopimaric acid derivative B above, and liquid epoxy compound D described later, at a temperature greater than 100°C but less than 200°C.

[0020] In the epoxy resin composition of the present invention, the reaction product C may be a reaction product of a mixture containing, for example, 0.3 to 20 parts by mass, or for example, 1 to 15 parts by mass, of levopimaric acid derivative B represented by formulas [2-1] to [2-5], relative to the total amount of epoxy compounds, i.e., the sum of epoxy compound A represented by formula [1] and the liquid epoxy compound D described later (100 parts by mass).

[0021] [Liquid epoxy compound D] The epoxy resin composition of the present invention contains a liquid epoxy compound D. The liquid epoxy compound D dissolves the epoxy compound A represented by the above formula [1], improves the handling properties 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 liquid epoxy compound D described above is not limited to aliphatic epoxy compounds, alicyclic epoxy compounds, and aromatic epoxy compounds, as long as it is a liquid epoxy compound. Among these, aromatic epoxy compounds are preferred, and in a preferred embodiment, a bifunctional aromatic epoxy compound D1 having two epoxy groups can be cited. In particular, it is preferable that the aromatic epoxy compound D1 is an epoxy compound having a bisphenol A-type skeleton or a bisphenol F-type skeleton.

[0022] The above aromatic epoxy compounds can be commercially available. Examples of the bifunctional aromatic epoxy compound D1 include jER(registered trademark) 806, a bisphenol F type epoxy compound manufactured by Mitsubishi Chemical Corporation, and jER(registered trademark) 828, a bisphenol A type epoxy compound also manufactured by Mitsubishi Chemical Corporation. Other examples of monofunctional aromatic epoxy compounds include phenyl glycidyl ether (e.g., Denacol® EX-141, manufactured by Nagase ChemteX Corporation), phenol (EO) 5 glycidyl ether (e.g., Denacol® EX-145, manufactured by Nagase ChemteX Corporation), and p-tert-butylphenyl glycidyl ether (e.g., Denacol® EX-146, manufactured by Nagase ChemteX Corporation).

[0023] Furthermore, examples of the above-mentioned aliphatic epoxy compounds and alicyclic epoxy compounds include monofunctional or difunctional aliphatic or alicyclic epoxy compounds, and commercially available products can be used for these. For example, the above monofunctional aliphatic epoxy compounds include oxiran-2-ylmethyl 2-(4,4-dimethylpentan-2-yl)-5,7,7-trimethyloctanoate (manufactured by Nissan Chemical Corporation, FOLDI® E101), etc.; and the difunctional aliphatic epoxy compounds include, but are not limited to, 2,2-bis(oxiran-2-ylmethoxy)methyl)butyl 2-(4,4-dimethylpentan-2-yl)-5,7,7-trimethyloctanoate (manufactured by Nissan Chemical Corporation, FOLDI® E201), etc. Examples of commercially available monofunctional alicyclic epoxy compounds include 3,4-epoxycyclohexylmethyl methacrylate (e.g., Cyclomer® M-100, manufactured by Daicel Corporation), 3,4-epoxycyclohexylmethyl acrylate (e.g., Cyclomer® A-200, manufactured by Daicel Corporation), 1,2-epoxy-4-vinylcyclohexane (e.g., Celoxide® 2000, manufactured by Daicel Corporation), and 1,2,8,9-diepoxylimonene (e.g., Celoxide® 3000, manufactured by Daicel Corporation). Examples of the above-mentioned bifunctional alicyclic epoxy compounds include diepoxybicyclohexyl (e.g., Celoxide® 8000 and 8010, manufactured by Daicel Corporation), 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexene carboxylate (e.g., Celoxide® 2021P, manufactured by Daicel Corporation), epsilon-caprolactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate (e.g., Celoxide® 2081, manufactured by Daicel Corporation), bis(3,4-epoxycyclohexylmethyl) adipate, and diepoxylated tetrahydroindene (e.g., Epocalic® THI-DE, manufactured by ENEOS Corporation).

[0024] In the epoxy resin composition of the present invention, epoxy compound D may be included in a proportion of, for example, 5 to 80 parts by mass, or 10 to 70 parts by mass, relative to the total amount of epoxy compounds, i.e., the total amount of epoxy compound A and epoxy compound D (100 parts by mass).

[0025] [Hardening agent E] The epoxy resin composition of the present invention may further contain a curing agent E. The curing agent is not particularly limited, but for example, acid anhydrides, amines, phenolic resins, polyamide resins, imidazoles, polymercaptans, or mixtures thereof can be used. Among these, acid anhydrides and amines are particularly preferred. These curing agents can be used even if they are solid, by dissolving them in a solvent. However, because evaporation of the solvent can lead to a decrease in the density of the cured product, the formation of pores, and a reduction in strength and water resistance, it is preferable that the curing agent itself be liquid at room temperature and atmospheric pressure. The curing agent can be contained in an amount of 0.5 to 1.5 equivalents, preferably 0.8 to 1.2 equivalents, per equivalent of epoxy groups in the total epoxy compound, i.e., epoxy compound A represented by formula [1] and liquid epoxy compound D combined. The equivalent amount of curing agent relative to the epoxy compound is expressed as the equivalent ratio of the curable groups of the curing agent to the epoxy groups. When other epoxy compounds are used in combination with epoxy compound A represented by formula [1] and liquid epoxy compound D, the equivalent amount of all those epoxy compounds relative to the epoxy groups will be within the above range.

[0026] As acid anhydrides, anhydrides of compounds having multiple carboxyl groups in one molecule are preferred. Examples of these acid anhydrides include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, ethylene glycol bistrimellitate, glycerol trimellitate, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, methylcyclohexendicarboxylic anhydride, and chloride anhydride. Among these, methyltetrahydrophthalic anhydride, methyl-5-norbornene-2,3-dicarboxylic acid anhydride (methylnadic anhydride, methylhymic anhydride), hydrogenated methylnadic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, methylhexahydrophthalic anhydride, or a mixture of methylhexahydrophthalic anhydride and hexahydrophthalic anhydride are preferred, as they are liquid at room temperature and atmospheric pressure. These liquid acid anhydrides have a viscosity of approximately 10 to 1,000 mPa·s when measured at 25°C. In the acid anhydride group, one acid anhydride group is calculated as one equivalent.

[0027] 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, xylenediamine, metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone. Among these, liquid diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, bis(1-methyl-2-aminocyclohexyl)methane, menthanediamine, isophoronediamine, and diaminodicyclohexylmethane can be preferably used.

[0028] Examples of phenolic resins include phenol novolac resins and cresol novolac resins.

[0029] Polyamide resins are produced by the condensation of dimer acids and polyamines, and are polyamidoamines that contain primary and secondary amines in their molecules.

[0030] Examples of imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, and epoxyimidazole adduct.

[0031] Polymercaptans are, for example, those in which mercaptan groups are present at the ends of polypropylene glycol chains or polyethylene glycol chains, and are preferably in liquid form.

[0032] As a curing agent E, dicyandiamide, known as a latent curing agent, can also be used. Dicyandiamide is a latent curing agent with excellent storage stability at room temperature, as it hardly dissolves in epoxy resin at room temperature, but dissolves and reacts with the epoxy group (cures) when heated to 180°C or higher. If it is desired to lower the curing temperature, as described later, the curing temperature can be lowered to, for example, 120-140°C by using a urea-based or imidasol-based curing accelerator F in combination. Dicyandiamide also has the characteristic of being able to maintain a semi-cured state for a certain period of time, and the cured product can exhibit high heat resistance and high adhesive strength. Because dicyandiamides contain catalytic functional groups (-CN groups) within the compound, they generally do not need to be stoichiometrically equivalent to the epoxy group, and curing can occur even with less than an equivalent amount.

[0033] [Curing accelerator F] The epoxy resin composition of the present invention may optionally contain a curing accelerator F (also called a curing aid) in addition to the curing agent E. Examples of curing accelerators include organophosphorus compounds such as triphenylphosphine and tributylphosphine; quaternary phosphonium salts such as ethyltriphenylphosphonium bromide and tetrabutylphosphonium O,O-diethylphosphodithioate; and quaternary ammonium salts such as 1,8-diazabicyclo[5.4.0]undeca-7-ene, salts of 1,8-diazabicyclo[5.4.0]undeca-7-ene with octic acid, zinc octoate, and tetrabutylammonium bromide. In addition, imidazoles such as 2-methylimidazole and 2-ethyl-4-methylimidazole, which were listed as curing agents above, and amines such as 2,4,6-tris(dimethylaminomethyl)phenol and benzyldimethylamine can also be used as curing accelerators for other types of curing agents. Furthermore, when using the aforementioned dicyanamide (DICY) as a curing agent, urea derivatives such as phenyldimethylurea and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), or the above-mentioned imidazoles and amines can be used. These curing accelerators can be used in a ratio of 0.001 to 5 parts by mass per 1 part by mass of the curing agent.

[0034] The epoxy resin composition of the present invention may optionally contain a solvent. The solvent is not particularly limited as long as it does not impair the effects of the present invention, but alcohols, ketones, ethers, and esters can be used. The aforementioned solvent is, Examples of alcohols include methanol, ethanol, propanol, isopropanol, n-butanol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, etc. Ketones include cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, γ-butyl lactone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, etc. Examples of ethers include butyl cellosolve; Examples of esters include, but are not limited to, ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, and propylene glycol monomethyl ether acetate.

[0035] [Other ingredients] The epoxy resin composition of the present invention may optionally contain conventional additives. Examples of such additives include curing catalysts (photoacid generators, thermoacid generators, base generators, etc.), curable monomers (cationic curable monomers such as vinyl group-containing compounds and oxetanyl group-containing compounds), thickeners, sensitizers, defoamers, leveling agents, coatability improvers, lubricants, stabilizers (antioxidants, heat stabilizers, light-resistant stabilizers, etc.), plasticizers, surfactants (fluorine-based surfactants, silicone-based surfactants, nonionic surfactants, etc.), adhesion promoters, dissolution promoters, fillers, antistatic agents, and curing agents. These additives may be used individually or in combination of two or more.

[0036] [Method for producing epoxy resin composition] The method for producing the epoxy resin composition of the present invention is not particularly limited, but it is preferable to produce it by stirring a mixture containing epoxy compound A represented by formula [1], at least one levopimaric acid derivative B selected from the group consisting of compounds represented by formulas [2-1] to [2-5], and the liquid epoxy compound D at a temperature of more than 100°C but less than 200°C.

[0037] Furthermore, an epoxy resin composition containing the curing agent E can be produced by including the steps of cooling the mixture to room temperature or below 100°C after the stirring step, and then adding the curing agent E to the mixture and stirring after cooling. A curing accelerator F may also be added when adding the curing agent E. When adding a curing agent E (and optionally a curing accelerator F), a portion of the liquid epoxy compound D may be set aside during the stirring step of epoxy compound A and epoxy compound D. This portion of liquid epoxy compound D can then be mixed with the curing agent E (and optionally a curing accelerator F) and added to the mixture. Furthermore, after adding the curing agent E (and optionally the curing accelerator F), it is preferable to stir and mix under reduced pressure to remove air bubbles.

[0038] [Epoxy cured material] The epoxy resin composition of the present invention can be applied to a substrate or poured into a casting plate coated with a release agent, and a cured product can be obtained by pre-curing at a temperature of, for example, 100-120°C (if necessary), and then main curing (post-curing) at a temperature of 120-200°C. The heating time can be adjusted as appropriate depending on the size and thickness of the epoxy resin. For example, both pre-curing and main curing can take 1-12 hours, or for example, 2-5 hours. The cured product of the epoxy resin composition of the present invention is also a subject of this invention.

[0039] [Method for suppressing the precipitation of epoxy compound A] The present invention also relates to a method for suppressing the precipitation of epoxy compound A in an epoxy resin composition comprising epoxy compound A represented by the above formula [1] and liquid epoxy compound D. The above precipitation suppression method is characterized in that the epoxy resin composition contains the isocyanuric acid type epoxy compound as a reaction product with a levopimaric acid derivative, that is, it contains a reaction product C of at least one levopimaric acid derivative B selected from the group consisting of compounds represented by formulas [2-1] to [2-5] above and the epoxy compound A. [Examples]

[0040] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0041] The apparatus and conditions used for sample preparation and analysis of physical properties in the examples are as follows. (1) NMR Equipment: AVANCE III (600MHz) [Bruker] Measurement conditions: 13 C-NMR Deuterated solvent: DMSO-d6 (2) Viscosity (rheometer) Device: MCR-302 [Manufactured by Anton Paar] Measurement speed: 1rpm, measurement temperature: 70℃, 100℃ (3) Glass transition temperature Tg Equipment: Dynamic viscoelasticity measuring device DMA Q800 [manufactured by TA Instruments] Transformation mode: Dual cantilever Frequency: 1Hz Distortion: 0.05% Sweep temperature: 30~300℃ Heating rate: 5°C / min (4) Bending strength, bending modulus, and deflection Equipment: Desktop precision universal testing machine Autograph AGS-5kNX [(Manufactured by Shimadzu Corporation)] Measurements were taken in accordance with JIS K-6911. (4-1) Bending strength The height (thickness) and width of the test specimen were measured. The specimen was supported, and a load was applied to its center using a pressure wedge. The load at which the specimen broke was measured. When P: load at which the specimen broke (N) {kgf}, L: distance between supports (mm), W: width of the specimen (mm), and h: height of the specimen (mm), the bending strength σ: (MPa) {kgf / mm 2 The value of} was calculated based on the following formula. Bending strength σ = (3PL) / (2Wh) 2 ) (4-2) Flexural modulus Flexural modulus (E): (MPa) {kgf / mm 2 If F / Y is the gradient (N / mm) of the straight portion of the load-deflection curve, then it can be calculated using the following formula. Flexural modulus E = [L 3 / (4Wh 3 )〕×〔F / Y〕

[0042] The abbreviations for each component used in the examples are as follows: TEPIC-S: Triglycidyl isocyanurate [Manufactured by Nissan Chemical Corporation, Product name: TEPIC(registered trademark)-S, Epoxy equivalent: 100g / eq.] jER828: Bisphenol A type epoxy resin [Manufactured by Mitsubishi Chemical Corporation, jER(registered trademark) 828, epoxy equivalent: 185g / eq.] Ad-1: Abietic acid [Manufactured by Tokyo Chemical Industry Co., Ltd., (purity > 80.0%)] Ad-2: Hydrogenated acrylic rosin [Contains 30-50% by mass of dihydroacrylopimaric acid represented by formula (2-4a), acid value: 239.6 mg KOH / g, manufactured by Arakawa Chemical Industries, Ltd.] Ad-3: Terephthalic acid [Manufactured by Tokyo Chemical Industry Co., Ltd.] MH-700: Ricacid (registered trademark) MH-700 [Manufactured by Shin-Nippon Rika Co., Ltd., a mixture of 4-methylcyclohexane-1,2-dicarboxylic acid anhydride and cyclohexane-1,2-dicarboxylic acid anhydride, acid anhydride equivalent: 165 g / eq.] Ad-4: Acrylic acid modified rosin [Acrylopimaric acid represented by formula (2-3a) Contains 60~70% by mass, acid value: 247.1mgKOH / 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-diethylphosphorodithioate [Manufactured by Nippon Chemical Industrial Co., Ltd., Hishikorin® PX-4ET] DICY: Dicyandiamide [Manufactured by Mitsubishi Chemical Corporation, jER Cure® 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.]

[0043] ( reference example 9 ) Add 10g of TEPIC-S, 9g of jER828, and 1g of Ad-1 to a container, and heat and mix at 150°C for 1 hour. reference example 9 An epoxy resin composition was obtained.

[0044] (Example 2) , Example 4 Examples 12, 24-29, Comparative Examples 1-10, Reference example 10 ) Except for the changes made to the ingredients and their amounts as shown in Table 1, reference example 9 Examples using the same procedure , reference example And comparative epoxy resin compositions were obtained. For Comparative Examples 7 and 8, which contained Ad-3, the heating conditions during preparation were 160°C for 3 hours, while for Comparative Examples 9 and 10, which contained Ad-5, the heating conditions were 160°C for 2 hours. Furthermore, in the following explanation, the example numbers for epoxy resin compositions will also be treated as example numbers for performance evaluation and physical property evaluation.

[0045] In the epoxy resin composition of Example 6, it was confirmed that reaction product C was generated by the following method. Regarding TEPIC-S (epoxy compound A), Ad-2 (levopimaric acid derivative B), jER828 (liquid epoxy compound D), the resin composition of Example 6, and the resin composition of Comparative Example 1: 13 ¹¹C-NMR spectra were measured, and the peak intensities before and after the reaction were compared. As a result, the peak originating from the carboxyl group of Ad-2 (176-180 ppm) disappeared, and a new peak originating from the ester bond resulting from the reaction between the carboxyl group of Ad-2 and the epoxy group of TEPIC-S was observed on the high-field side (174-178 ppm). This confirmed that TEPIC-S (epoxy compound A) and Ad-2 (levopimaric acid derivative B) reacted to form reaction product C. Other examples , reference example The resin composition was also confirmed using a similar method.

[0046] [Performance evaluation of epoxy resin compositions] (1) Presence or absence of crystal precipitation Examples 2. Example 4 Examples 12, 24-29, Comparative Examples 1-10 , Reference example 9, Reference example 10 The epoxy resin composition was placed in a glass container, sealed, and left at room temperature for one week. The presence or absence of crystal precipitation was then visually observed. The evaluation was conducted according to the following criteria. The results are shown in Table 1. <Evaluation Criteria> A: No crystal precipitation, N: Crystal precipitation present

[0047] (2) Viscosity measurement of epoxy resin composition Examples 2、4 Examples 24-25, Comparative Examples 1, 7-10 , Reference examples 9, 10 The viscosity of the epoxy resin composition was measured at 70°C and 100°C. The results are shown in Table 1.

[0048] [Table 1]

[0049] Examples prepared including Ad-1, Ad-2, or Ad-4 are shown in Table 1. 2 , Example 4~ Examples 12 and 24-29 , Reference examples 9, 10 No crystal precipitation was observed in the epoxy resin composition after being left at room temperature for one week. On the other hand, the epoxy resin compositions of Comparative Examples 1 to 6, which were prepared without using Ad-1, Ad-2, or Ad-4, showed crystal precipitation after being left at room temperature for one week, confirming a lack of storage stability.

[0050] Examples 2、 Example 4 、 Examples 24-25 and Reference Examples 9 and 10 Compared to the epoxy resin composition of Comparative Example 1, which did not contain Ad-1, Ad-2, or Ad-4, the epoxy resin composition showed an increase in viscosity, but it remained at a low viscosity of approximately 1,000 mPa·s or less at 70°C and approximately 130 mPa·s or less at 100°C, confirming excellent fluidity. On the other hand, the epoxy resin compositions of Comparative Examples 7 and 8, which were prepared by including Ad-3 (terephthalic acid) instead of Ad-1, Ad-2, or Ad-4, and the epoxy resin compositions of Comparative Examples 9 and 10, which were prepared by including Ad-5 (1,4-cyclohexanedicarboxylic acid), did not show crystal precipitation after being left at room temperature for one week, even though the formulation of each component was equivalent. to Examples , reference example Compared to the epoxy resin composition, the viscosity at both 70°C and 100°C is higher (compared to Comparative Examples 7 and 9). reference example 9 For Example 2 or Example 25, Comparative Example 8 and Comparative Example 10 reference example 10 In Example 4 or Example 24, the resin composition was found to have poor handling properties.

[0051] [Cured product properties of epoxy resin composition 1 (curing agent: MH-700, PX-4ET)] ( reference example 11 ) 10.5 g of TEPIC-S, 9.45 g of jER828, and 1.05 g of Ad-1 were added to a container, heated and mixed at 150°C for 1 hour, and then cooled to 70°C. Subsequently, 25.575 g of MH-700 (epoxy equivalent ratio: 1 equivalent) was added as a curing agent, and 0.210 g of PX-4ET was added as a curing accelerator. This mixture was degassed under reduced pressure while stirring at 70°C for 30 minutes to obtain an epoxy resin composition.

[0052] (Example 1) 4. Example 16~ Example 20, Reference Examples 1 to 5, Reference example 12 ) Except for the changes to the ingredients and their amounts as shown in Table 2, reference example 11 The epoxy resin compositions for each example and reference example were obtained using the same procedure. In Reference Examples 1 and 3, which incorporate Ad-3, the conditions for heating and mixing TEPIC-S, jER828, and Ad-3 were 160°C for 3 hours.

[0053] Each composition was sandwiched between two glass substrates that had been pre-treated with Optool® DSX [manufactured by Daikin Industries, Ltd.], along with a 3mm thick U-shaped silicone rubber spacer. This was heated at 100°C for 2 hours (pre-curing), and then the temperature was raised to 150°C and heated for 5 hours (main curing). After slow cooling, the glass substrates were removed to obtain 3mm thick cured products. The glass transition temperature, flexural strength (stress), flexural modulus, and deflection of the obtained cured material were evaluated. Each physical property was measured using the following procedure. The results are shown in Table 2.

[0054] [Glass transition temperature (Tg)] The storage modulus E' and loss modulus E'' were measured using DMA, and the temperature at which the value of tanδ(loss modulus E'' / storage modulus E') obtained from these values ​​was maximized was defined as Tg.

[0055] [Bending strength (stress), bending modulus, deflection] Measurements were taken in accordance with JIS K-6911:2006. Specifically, a load was applied with a pressure wedge to the center of a test piece (80×10×3 mm) supported with a distance between supporting points of 64 mm, and the gradient F / Y [N / mm] of the linear portion of the load-deflection curve was determined. Further, the load P [N] at which the test piece fractured was determined. From these values and the values of the distance between supporting points L [mm], the width W [mm] of the test piece, and the thickness h [mm] of the test piece, the flexural modulus was calculated by the following formula. Flexural modulus [MPa] = (L 3 ÷ 4Wh 3 ) × (F / Y) Flexural strength (stress) [MPa] = 3PL ÷ 2Wh 2 Further, the deflection at break (indentation distance) was evaluated as [deflection].

[0056]

Table 2

[0057] [Cured product properties 2 of epoxy resin composition (curing agents: DICY, DCMU)] (Example 21) 13.5 g of TEPIC-S, 9.45 g of jER828 (30% by mass of the total amount of jER828 used), and 2.25 g of Ad-2 were added into a container, heated and mixed at 150°C for 1 hour, then cooled to 70°C. Thereafter, a mixture treated in advance with a three-roll mill (22.05 g of jER828 (70% by mass of the total amount of jER828 used), 1.35 g of DICY, and 1.35 g of DCMU) was further added. This was subjected to vacuum degassing while stirring at 70°C for 30 minutes to obtain an epoxy resin composition.

[0058] (Examples 22 to 23, Reference Examples 6 to 8) Cured products of each Example and each Reference Example were obtained by the same procedure as in Example 21, except that the blending components and the blending amounts thereof were changed as shown in Table 3.

[0059] Each composition was sandwiched between two glass substrates that had been pre-treated with Optool® DSX [manufactured by Daikin Industries, Ltd.], along with a 3mm thick U-shaped silicone rubber spacer. This was heated (cured) at 130°C for 2 hours, then slowly cooled, after which the glass substrates were removed to obtain each cured product with a thickness of 3mm. Regarding the cured product obtained, see Example 14 above. Examples 16~ Example 20 and Reference Examples 1 to 5 , Reference example 11, Reference example 12 Using the same procedure, the glass transition temperature, bending strength (stress), bending modulus, and deflection were evaluated. The results are shown in Table 3.

[0060] [Table 3]

[0061] As shown in Table 2, the cured epoxy resin compositions prepared using Ad-1 or Ad-2 exhibited glass transition temperatures, flexural strength (stress), flexural modulus, and deflection equivalent to those of the cured epoxy resin compositions prepared using Ad-3, and those prepared without using Ad-1 to Ad-3. Furthermore, as shown in Table 3, even when the type of curing agent was changed, the cured products of epoxy resin compositions prepared using Ad-2 and those prepared without Ad-2 showed equivalent cured product properties.

[0062] [Evaluation of solvent solubility of epoxy resin compositions] (Epoxy resin composition A) 10g of TEPIC-S, 10g of jER828, and 2g of Ad-2 were added to a container and heated and mixed at 150°C for 1 hour to obtain epoxy resin composition A. (Epoxy resin composition B) 10g of TEPIC-S and 10g of jER828 were added to a container and heated and mixed at 150°C for 1 hour to obtain epoxy resin composition B.

[0063] (Example 30) One g of epoxy resin composition A and nine g of solvent MEK were placed in a glass container and mixed. The solubility of the epoxy resin composition in the solvent and the presence or absence of crystal precipitation after being left at room temperature for two weeks were observed visually. The evaluation was conducted according to the following criteria. The results are shown in Table 4. <Evaluation Criteria> A: Uniform dissolution and no crystal precipitation even after 2 weeks. B: Uniform dissolution occurs, but crystal precipitation occurs within one week. C: Does not dissolve uniformly (insoluble)

[0064] (Examples 31-33) Solvent solubility was evaluated using the same procedure as in Example 30, except that the components and their amounts were changed as shown in Table 4.

[0065] (Comparative Example 11-14) Solvent solubility was evaluated using the same procedure as in Example 30, except that the components and their amounts were changed as shown in Table 5.

[0066] [Table 4]

[0067] [Table 5]

[0068] As shown in Examples 30 to 33 of Table 4, epoxy resin composition A prepared using Ad-2 showed uniform dissolution of its components in MEK and PGMEA, and crystal precipitation was suppressed when left at room temperature. On the other hand, as shown in Comparative Examples 11-14 of Table 5, when epoxy resin composition B was prepared without using Ad-2, the components dissolved uniformly when MEK was used as the solvent, but crystal precipitation was observed when left at room temperature, and when PGMEA was used as the solvent, the components did not dissolve.

[0069] As shown in Tables 1 to 5 above, the epoxy resin composition of the present invention was confirmed to suppress the precipitation of epoxy compounds during storage without adversely affecting the curability or cured product properties of the composition, and to have excellent fluidity of the resin composition.

Claims

1. The reaction product C of epoxy compound A represented by formula [1] and at least one levopimaric acid derivative B selected from the group consisting of compounds represented by formulas [2-1], [2-3], [2-4] and [2-5], and Liquid epoxy compound D An epoxy resin composition comprising, An epoxy resin composition in which the reaction product C is a reaction product of a mixture containing 0.3 to 20 parts by mass of the levopimaric acid derivative B with respect to 100 parts by mass of the total of epoxy compound A and epoxy compound D. 【Chemistry 1】 (In the formula, R １ ~R ３ Each of these independently represents a hydrogen atom or a methyl group, L １ ~L ３ Each of these independently represents an alkylene group having 1 to 10 carbon atoms. 【Chemistry 2】 (In the above formula, R ４ , R ４’ , R ５ , R ５’ , R ６ , R ７ , R ８ , and R ８’ each independently represent a hydrogen atom, or a linear or branched alkyl group having 1 to 6 carbon atoms, R ９ , R ９’ , R １０ , and R １０’ Each of these independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, -COOM, or R ９ or R ９’ and R １０ or R １０’ They combine to form acid anhydrides, M represents a hydrogen atom, an alkali metal atom, or an alkaline earth metal atom (however, in formula [2-1] above, R ４ is an isopropyl group, R ５ is a hydrogen atom, R ５’ is a hydrogen atom, R ６ is a methyl group, R ７ is a methyl group, R ８ Compounds in which is a hydrogen atom and M is a hydrogen atom are excluded.

2. The levopimaric acid derivative B is at least one compound selected from the group consisting of compounds represented by the following formula. The epoxy resin composition according to claim 1. 【Transformation 3】 (In the formula, M' represents an alkali metal atom or an alkaline earth metal atom.)

3. The epoxy resin composition according to claim 1, wherein the epoxy compound D is an aromatic epoxy compound.

4. The epoxy resin composition according to claim 3, wherein the aromatic epoxy compound is a bifunctional aromatic epoxy compound D1.

5. The epoxy resin composition according to claim 4, wherein the difunctional aromatic epoxy compound D1 is an epoxy compound having a bisphenol A-type skeleton or a bisphenol F-type skeleton.

6. Furthermore, the epoxy resin composition according to claim 1, further comprising a curing agent E.

7. The epoxy resin composition according to claim 6, wherein the curing agent E is at least one selected from the group consisting of acid anhydrides, amines, phenolic resins, polyamide resins, imidazoles, polymer captans, and dicyanamides.

8. An epoxy cured body which is a cured product of the epoxy resin composition according to any one of claims 1 to 7.

9. Epoxy compound A represented by the following formula [1], At least one levopimaric acid derivative B selected from the group consisting of compounds represented by the following formulas [2-1], [2-3], [2-4], and [2-5], and The process includes stirring a mixture containing liquid epoxy compound D at a temperature greater than 100°C but less than 200°C. A method for producing an epoxy resin composition containing reaction product C of epoxy compound A and levopimaric acid derivative B. 【Chemistry 4】 (In the formula, R １ ~R ３ Each of these independently represents a hydrogen atom or a methyl group, L １ ~L ３ Each of these independently represents an alkylene group having 1 to 10 carbon atoms. 【Transformation 5】 (In the above formula, R ４ , R ４’ , R ５ , R ５’ , R ６ , R ７ , R ８ , and R ８’ Each of these independently represents a hydrogen atom and a linear or branched alkyl group having 1 to 6 carbon atoms. R ９ , R ９’ , R １０ , and R １０’ Each of these independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, -COOM, or R ９ or R ９’ and R １０ or R １０’ They combine to form acid anhydrides, M represents a hydrogen atom, an alkali metal atom, or an alkaline earth metal atom (however, in formula [2-1] above, R ４ is an isopropyl group, R ５ is a hydrogen atom, R ５’ is a hydrogen atom, R ６ is a methyl group, R ７ is a methyl group, R ８ Compounds in which is a hydrogen atom and M is a hydrogen atom are excluded.

10. After the stirring step, the mixture is further cooled to a temperature of room temperature to 100°C or lower. The process includes adding the curing agent E to the mixture after cooling and stirring, A method for producing the epoxy resin composition according to claim 9.

11. A method for 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, A method for suppressing precipitation, characterized in that the epoxy resin composition contains a reaction product C of at least one levopimaric acid derivative B selected from the group consisting of compounds represented by the following formulas [2-1], [2-3], [2-4], and [2-5], and the epoxy compound A. 【Chemistry 1】 (In the formula, R １ ~R ３ Each of these independently represents a hydrogen atom or a methyl group, L １ ~L ３ Each of these independently represents an alkylene group having 1 to 10 carbon atoms. 【Chemistry 2】 (In the above formula, R ４ , R ４’ , R ５ , R ５’ , R ６ , R ７ , R ８ , and R ８’ Each of these independently represents a hydrogen atom and a linear or branched alkyl group having 1 to 6 carbon atoms. R ９ , R ９’ , R １０ , and R １０’ Each of these independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, -COOM, or R ９ or R ９’ and R １０ or R １０’ They combine to form acid anhydrides, M represents a hydrogen atom, an alkali metal atom, or an alkaline earth metal atom (however, in formula [2-1] above, R ４ is an isopropyl group, R ５ is a hydrogen atom, R ５’ is a hydrogen atom, R ６ is a methyl group, R ７ is a methyl group, R ８ Compounds in which is a hydrogen atom and M is a hydrogen atom are excluded.

Images