Curable epoxy composition

Abstract

Provided is a curable epoxy composition which can be cured in a short time in the presence of oxygen and which has excellent filling properties. A curable epoxy composition containing an epoxy compound having an epoxy group in the molecule and a photo-cationic polymerization initiator, the curable epoxy composition being used for use in a rotary electric machine and / or a semiconductor. It is preferable that the curable epoxy composition substantially does not contain a curing agent other than a photo-cationic polymerization initiator. The curable epoxy composition may also include a polyol.

Description

Technical Field

[0001] This disclosure relates to a curable epoxy composition for use in rotating electrical machines and / or semiconductors. More specifically, in one embodiment, this disclosure relates to a curable epoxy composition for forming a cured product used in the stator or rotor of a rotating electrical machine. Furthermore, this application claims priority to Japanese Patent Application No. 2023-139154, filed on August 29, 2023, the contents of which are incorporated herein by reference. Background Technology

[0002] Free radical polymerizable compounds, epoxy resins used as molded coils such as ignition coils impregnated / molded, resins for rotating motors (e.g., insulating materials, adhesive resins for fixing permanent magnets, filling materials for gaps, etc.) etc. (e.g., see Patent Documents 1 to 3).

[0003] For example, Patent Document 1 discloses a resin composition for coating insulated copper wires, comprising a base unsaturated polyester resin and / or a base vinyl ester resin, a free radical polymerizable monomer, and a photoradical polymerization initiator. Furthermore, Patent Document 2 discloses an epoxy resin composition for a rotating electric motor comprising an epoxy resin and a sulfonate cationic polymerization initiator. Patent Document 3 discloses a powder coating comprising an epoxy resin and an anhydride-based curing agent as a resin composition for filling gaps in copper wires of a coil.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-19457

[0007] Patent Document 2: Japanese Patent Application Publication No. 2005-245143

[0008] Patent Document 3: Japanese Patent Application Publication No. 2020-157183 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, resin compositions containing free radical polymerizable monomers, as described in Patent Document 1, require oxygen isolation for curing in order to undergo free radical polymerization. When curing components with complex structures, such as rotary motors, the method of oxygen isolation for curing becomes cumbersome. Furthermore, when using thermal cationic polymerization initiators as described in Patent Document 2, the curing time becomes longer. If the curing process is complex or the curing time is long, liquid dripping can occur during the coating and curing process, resulting in poor workability. In addition, powder coatings as described in Patent Document 3 have poor gap-filling properties.

[0011] Therefore, the purpose of this disclosure is to provide a curable epoxy composition that can be cured in the presence of oxygen for a short time and has excellent filling properties.

[0012] Solution for solving the problem

[0013] The inventors of this disclosure conducted in-depth research to achieve the aforementioned objectives and discovered that a curable epoxy composition comprising an epoxy compound having intramolecular epoxy groups and a photocationic polymerization initiator can be cured quickly in the presence of oxygen and exhibits excellent filling properties. This disclosure relates to technical solutions based on these insights.

[0014] This disclosure provides a curable epoxy composition comprising an epoxy compound having an intramolecular epoxy group and a photocationic polymerization initiator, the curable epoxy composition being intended for use in rotary motors and / or semiconductor applications.

[0015] Preferably, the above-mentioned curable epoxy composition does not contain curing agents other than the above-mentioned photocationic polymerization initiator.

[0016] Preferably, the above-mentioned curable epoxy composition contains a polyol.

[0017] Preferably, the content of the epoxy compound relative to the total amount of the cationic curable compound is 90% by mass or more.

[0018] Preferably, the above-mentioned curable epoxy composition does not substantially contain free radical polymerizable compounds.

[0019] Preferably, the above-mentioned curable epoxy composition contains an inorganic filler.

[0020] Preferably, the above-mentioned curable epoxy composition is liquid at 25°C.

[0021] Preferably, the curable epoxy composition is a curable epoxy composition for impregnating the stator coil of the rotary motor, or a curable epoxy composition for fixing a magnet inserted into a hole provided in the rotor core of the rotary motor to the inner wall of the hole.

[0022] Furthermore, this disclosure provides a cured product, which is a cured product of the above-mentioned curable epoxy composition.

[0023] Furthermore, this disclosure provides a stator for a rotary electric machine, which is formed in a manner that covers stator coils.

[0024] Furthermore, this disclosure provides a stator for a rotating electric motor having the aforementioned solidified material covering the windings of a rotor.

[0025] Invention Effects

[0026] The curable epoxy composition disclosed herein can cure rapidly in the presence of oxygen and exhibits excellent filling properties. Therefore, when coating components with complex structures using the curable epoxy composition, liquid dripping is less likely to occur during curing. Furthermore, surface tackiness is reduced early on, resulting in excellent workability. In addition, the rapid curing time helps reduce CO2 emissions and environmental impact. Detailed Implementation

[0027] [Curing epoxy composition]

[0028] The curable epoxy composition disclosed herein is a composition that contains at least an epoxy compound having an intramolecular epoxy group and a photocationic polymerization initiator, and has both photocurable and thermocurable properties.

[0029] (Epoxy compounds)

[0030] The aforementioned epoxy compounds are compounds having one or more epoxy groups (epoxyethyl groups) within their molecules. Preferably, the epoxy compounds have two or more epoxy groups (preferably 2 to 6, more preferably 2 to 4). Only one type of epoxy compound may be used, or two or more types may be used.

[0031] As the aforementioned epoxy compounds, well-known or conventional epoxy compounds can be used without particular limitation. Examples include: alicyclic epoxy compounds (alicyclic epoxy resins); aliphatic epoxy compounds such as aliphatic polyglycidyl ethers (aliphatic epoxy resins); aromatic epoxy compounds such as bisphenol A type epoxy compounds (aromatic epoxy resins); heterocyclic epoxy compounds (heterocyclic epoxy resins), etc.

[0032] The aforementioned alicyclic epoxy compounds are compounds that have at least an alicyclic (aliphatic hydrocarbon ring) structure and an epoxy group within their molecules. As such alicyclic epoxy compounds, known or conventional alicyclic epoxy compounds can be used without particular limitation; examples include: (I) compounds having an epoxy group (called "alicyclic epoxy group") formed by two adjacent carbon atoms and an oxygen atom constituting the alicyclic ring within their molecules; (II) compounds with an epoxy group directly bonded to the alicyclic ring by a single bond; and (III) compounds having an alicyclic ring and a glycidyl ether group within their molecules (glycidyl ether type epoxy compounds), etc.

[0033] As compounds having an alicyclic epoxy group in the molecule of (I) above, compounds having an epoxy cyclohexyl group can be listed, for example, compounds shown in the following formula (i).

[0034]

[0035] In formula (i) above, Y represents a single bond or a linking group (a divalent group having one or more atoms). Examples of such linking groups include: divalent hydrocarbon groups, alkenyl groups with part or all of the carbon-carbon double bond epoxidized, carbonyl groups, ether bonds, ester bonds, carbonate groups, amide groups, and groups formed by the linkage of multiple of these. It should be noted that one or more carbon atoms constituting the cyclohexane ring (epoxycyclohexyl) in formula (i) are optionally bonded to substituents such as alkyl groups.

[0036] Examples of divalent hydrocarbon groups include straight-chain or branched alkylene groups and divalent alicyclic hydrocarbon groups with 1 to 18 carbon atoms. Examples of straight-chain or branched alkylene groups with 1 to 18 carbon atoms include methylene, methylmethylene, dimethylmethylene, ethylene, propylene, and trimethylene. Examples of divalent alicyclic hydrocarbon groups include 1,2-cyclopentylene, 1,3-cyclopentylene, cyclopentylene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1,4-cyclohexylene, and cyclohexylene, etc., which are divalent cycloalkylene groups (including cycloalkylene groups).

[0037] Examples of alkenyl groups (sometimes called "epoxidized alkenyl groups") in which part or all of the aforementioned carbon-carbon double bonds are epoxidized include: vinylidene, propenide, 1-butenide, 2-butenide, butadienylene group, pentenide, hexenide, heptenide, octene, and other straight-chain or branched alkenyl groups with 2 to 8 carbon atoms. In particular, alkenyl groups in which all of the carbon-carbon double bonds are epoxidized are preferred, and alkenyl groups in which all of the carbon-carbon double bonds are epoxidized with 2 to 4 carbon atoms are more preferred.

[0038] Representative examples of alicyclic epoxy compounds shown in formula (i) above include (3,4,3',4'-diepoxy)bicyclohexane and compounds shown in formulas (i-1) to (i-10) below. It should be noted that in formulas (i-5) and (i-7) below, l and m represent integers from 1 to 30. In formula (i-5) below, R' is an alkylene group having 1 to 8 carbon atoms, preferably a straight-chain or branched alkylene group having 1 to 3 carbon atoms, such as methylene, ethylene, propylene, or isopropylene. In formulas (i-9) and (i-10) below, n1 to n6 represent integers from 1 to 30. In addition, as alicyclic epoxy compounds represented by formula (i) above, other examples include 2,2-bis(3,4-epoxycyclohexyl)propane, 1,2-bis(3,4-epoxycyclohexane-1-yl)ethane, 1,2-epoxy-1,2-bis(3,4-epoxycyclohexane-1-yl)ethane, bis(3,4-epoxycyclohexylmethyl) ether, etc.

[0039]

[0040]

[0041] Furthermore, as compounds having alicyclic epoxy groups within the molecule of (1) above, epoxy-modified siloxanes can be listed as examples. As such epoxy-modified siloxanes, chain-like or cyclic polyorganosiloxanes having structural units shown in the following formula (i') can be listed as examples.

[0042]

[0043] In the above formula (i'), R 3 R represents a substituent containing a group represented by formula (1a) below or a substituent containing a group represented by formula (1b) below. 4 It indicates alkyl or alkoxy.

[0044]

[0045] In equations (1a) and (1b), R 1a R 1b The same or different indicates straight-chain or branched alkylene groups, such as methylene, methylmethylene, dimethylmethylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, decamethylene, etc., which are straight-chain or branched alkylene groups with 1 to 10 carbon atoms.

[0046] The epoxy equivalent (according to JIS K7236) of the above-mentioned epoxy-modified siloxane is, for example, 100 to 400, preferably 150 to 300.

[0047] As the aforementioned epoxy-modified siloxane, for example, commercially available products such as the compound shown in the following formula (i'-1) (trade name "X-40-2670", manufactured by Shin-Etsu Chemical Industry Co., Ltd.) can be used.

[0048]

[0049] As compounds in (II) above that have an epoxy group directly bonded to the alicyclic ring by a single bond, examples include compounds represented by the following formula (ii).

[0050]

[0051] In formula (ii), R” is a group (p-valent organic group) formed by removing p hydroxyl groups (-OH) from the structural formula of a p-hydronic alcohol, where p and n represent natural numbers. As a p-hydronic alcohol [R””OH] pExamples of compounds represented by formula (ii) include polyols such as 2,2-bis(hydroxymethyl)-1-butanol (alcohols with 1 to 15 carbon atoms). p is preferably 1 to 6, and n is preferably 1 to 30. When p is 2 or more, the n in each group within the parentheses can be the same or different. Specifically, examples of compounds represented by formula (ii) include 1,2-epoxy-4-(2-epoxyethyl)cyclohexane adducts of 2,2-bis(hydroxymethyl)-1-butanol [e.g., trade name "EHPE3150" (manufactured by DAICEL Co., Ltd.)].

[0052] As compounds containing an alicyclic ring and a glycidyl ether group within the molecule of (III) mentioned above, examples include glycidyl ethers of alicyclic alcohols (especially alicyclic polyols). More specifically, examples include: 2,2-bis[4-(2,3-epoxypropoxy)cyclohexyl]propane, 2,2-bis[3,5-dimethyl-4-(2,3-epoxypropoxy)cyclohexyl]propane, and other compounds formed by hydrogenating bisphenol A type epoxides (hydrogenated bisphenol A type epoxides); bis[o,o-(2,3-epoxypropoxy)cyclohexyl]methane, bis[o,p-(2,3-epoxypropoxy)cyclohexyl]methane, bis[p,p-(2,3-epoxypropoxy)cyclohexyl]methane, bis[o ... Compounds formed by hydrogenating bisphenol F type epoxides such as [3,5-dimethyl-4-(2,3-epoxypropoxy)cyclohexyl]methane (hydrogenated bisphenol F type epoxides); hydrogenated biphenol type epoxides; hydrogenated phenol linear phenolic type epoxides; hydrogenated cresol linear phenolic type epoxides; hydrogenated cresol linear phenolic type epoxides of bisphenol A; hydrogenated naphthalene type epoxides; hydrogenated epoxides of epoxides obtained from triphenolmethane; and hydrogenated epoxides of other epoxides having aromatic rings, etc.

[0053] Examples of the aforementioned aromatic epoxy compounds include: epi-bis-type glycidyl ether epoxy resins obtained by the condensation reaction of bisphenols (e.g., bisphenol A, bisphenol F, bisphenol S, bisphenol fluorene, etc.) with epihaloalcohols; high molecular weight epi-bis-type glycidyl ether epoxy resins obtained by further adding these epi-bis-type glycidyl ether epoxy resins to the aforementioned bisphenols; and epoxy resins obtained by reacting phenols (e.g., phenol, cresol, xylenol, resorcinol) with the aforementioned bisphenols. Polyols obtained by condensing catechol, bisphenol A, bisphenol F, bisphenol S, etc. with aldehydes [e.g., formaldehyde, acetaldehyde, benzaldehyde, hydroxybenzaldehyde, salicylaldehyde, etc.] are further condensed with epihaloalcohols to obtain linear phenolic / alkyl glycidyl ether type epoxy resins; epoxy compounds formed by bonding two phenolic skeletons at the 9 position of the fluorene ring, and by directly or via alkylene oxides bonding glycidyl groups to the oxygen atoms after removing hydrogen atoms from the hydroxyl groups of these phenolic skeletons.

[0054] Examples of the aforementioned aliphatic epoxides include: glycidyl ethers of q-hydroxides (q being a natural number) that do not have a cyclic structure; glycidyl esters of mono- or polycarboxylic acids [such as acetic acid, propionic acid, butyric acid, stearic acid, adipic acid, sebacic acid, maleic acid, itaconic acid, etc.]; epoxides of oils containing double bonds, such as epoxidized linseed oil, epoxidized soybean oil, and epoxidized castor oil; and epoxides of polyolefins (including polydienes) such as epoxidized polybutadiene. It should be noted that the aforementioned non-cyclic q-ols can include, for example: monohydric alcohols such as methanol, ethanol, 1-propanol, isopropanol, and 1-butanol; dihydric alcohols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polyethylene glycol, and polypropylene glycol; and polyols with three or more nucleotides such as glycerol, diglycerol, erythritol, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, and sorbitol. Furthermore, q-ols can also be polyether polyols, polyester polyols, polycarbonate polyols, and polyolefin polyols.

[0055] Examples of the aforementioned heterocyclic epoxides include epoxides that have an epoxy group and heterocycles other than the epoxy group within the molecule, such as tetrahydrofuran ring, tetrahydropyran ring, morpholine ring, chromium ring, isochorium ring, tetrahydrothiophene ring, tetrahydrothiophene ring, aziridine ring, pyrrolidine ring, piperidine ring, piperazine ring, indoline ring, 2,6-dioxabicyclo[3.3.0]octane ring, 1,3,5-triazacyclohexane ring, 1,3,5-triazacyclohexane-2,4,6-trione ring (isocyanuric ring), dihydroimidazo[4,5-d]imidazo-2,5-dione ring (glycourea ring), etc. (non-aromatic heterocycles); thiophene ring, pyrrole ring, furan ring, pyridine ring, etc. (aromatic heterocycles). Among them, heterocyclic epoxy compounds are preferably compounds composed of carbon atoms, hydrogen atoms, oxygen atoms and nitrogen atoms.

[0056] Examples of heterocyclic epoxy compounds include, for instance, epoxy compounds having an isocyanuric acid ring (epoxide compounds containing an isocyanuric acid ring) and epoxy compounds having a glycourea ring (epoxide compounds containing a glycourea ring). The number of epoxy groups within the molecule of the aforementioned epoxy compounds containing an isocyanuric acid ring is not particularly limited, but is preferably 1 to 6, more preferably 1 to 3. The number of epoxy groups within the molecule of the aforementioned epoxy compounds containing a glycourea ring is not particularly limited, but is preferably 1 to 6, more preferably 2 to 4.

[0057] Examples of epoxy compounds containing isocyanuric acid rings include compounds represented by formula (iii) below.

[0058]

[0059] In equation (iii), R 4 ~R 6 The same or different indicates a hydrogen atom or a monovalent organic group. Among them, R... 4 ~R 6 At least one of them is a monovalent organic group containing an epoxy group. Examples of such monovalent organic groups include: monovalent aliphatic hydrocarbon groups (e.g., alkyl, alkenyl, etc.); monovalent aromatic hydrocarbon groups (e.g., aryl, etc.); monovalent heterocyclic groups; and monovalent groups formed by the bonding of two or more aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. It should be noted that the monovalent organic group may have substituents (e.g., hydroxyl, carboxyl, halogen atoms, etc.). Examples of monovalent organic groups containing epoxy groups include: epoxy group, glycidyl group, 2-methylepoxypropyl group, epoxycyclohexyl group, and other monovalent organic groups containing epoxy groups described later.

[0060] Particularly preferred is R in equation (iii) 4 ~R 6 Whether the groups are the same or different, they are groups having the group shown in formula (iiia) or groups having the group shown in formula (iiib), and R 4 ~R 6 At least one of them is a group having the group shown in formula (iiia).

[0061]

[0062]

[0063] R in equations (iiia) and (iiib) above 7 and R 8 Whether the terms are the same or different, they refer to alkyl groups having 1 to 8 carbon atoms or hydrogen atoms. Examples of alkyl groups having 1 to 8 carbon atoms include straight-chain or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, pentyl, hexyl, heptyl, and octyl. Among these, straight-chain or branched alkyl groups having 1 to 3 carbon atoms, such as methyl, ethyl, propyl, and isopropyl, are preferred. R in formulas (iiia) and (iiib) 7 and R 8 Hydrogen atoms are particularly preferred.

[0064] In equations (iiia) and (iiib) above, X 1 and X 2 The terms "same" or "different" indicate divalent organic groups. These divalent organic groups can be divalent hydrocarbon groups, or groups formed by two or more divalent hydrocarbon groups bonded together by ester bonds, ether bonds, or other linking groups.

[0065] R in equation (iii) 4 ~R 6 Whether identical or different, it may have only one group having the group shown in formula (iiia) above and / or a group having the group shown in formula (iiib) above, or it may have two or more. R 4 ~R 6 The number of groups having the group shown in formula (iiia) and / or having the group shown in formula (iiib) is preferably 1 to 3, more preferably 1 to 2.

[0066] More specifically, examples of the above-mentioned epoxy compounds containing isocyanuric acid rings include compounds shown in formula (iii-1), compounds shown in formula (iii-2), and compounds shown in formula (iii-3).

[0067]

[0068]

[0069]

[0070] In equations (iii-1) to (iii-3) above, R 7 R 8 X 1 and X 2 Same or different, as in equations (iiia) and (iiib).

[0071] Representative examples of compounds shown in formula (iii-1) above include: monoallyl diglycidyl isocyanurate, 1-allyl-3,5-bis(2-methylepoxypropyl) isocyanurate, 1-(2-methylpropenyl)-3,5-diglycidyl isocyanurate, 1-(2-methylpropenyl)-3,5-bis(2-methylepoxypropyl) isocyanurate, etc.

[0072] Representative examples of compounds shown in formula (iii-2) above include: diallyl monoglycidyl isocyanurate, 1,3-diallyl-5-(2-methylepoxypropyl) isocyanurate, 1,3-bis(2-methylpropenyl)-5-glycidyl isocyanurate, 1,3-bis(2-methylpropenyl)-5-(2-methylepoxypropyl) isocyanurate, etc.

[0073] Representative examples of compounds shown in formula (iii-3) above include triglycidyl isocyanurate, tris(2-methylepoxypropyl)isocyanurate, etc.

[0074] Commercially available products containing the aforementioned isocyanuric acid ring include the TEPIC series (TEPIC-G, TEPIC-S, TEPIC-SS, TEPIC-HP, TEPIC-L, TEPIC-PAS, TEPIC-VL, TEPIC-UC) manufactured by Nissan Chemical Co., Ltd.

[0075] It should be noted that the above-mentioned epoxy compounds containing isocyanuric acid rings can also be pre-modified by adding compounds that react with epoxy groups, such as alcohols and acid anhydrides, before use.

[0076] Examples of the epoxy compounds containing the glycourea ring described above include compounds represented by formula (iv) below.

[0077]

[0078] In equation (iv), R 9 ~R 12 The same or different indicates a hydrogen atom or a monovalent organic group. Among them, R... 9 ~R 12 At least one of them is a monovalent organic group containing an epoxy group. Examples of such monovalent organic groups include those identical to the monovalent organic groups in the aforementioned epoxide compounds containing an isocyanuric acid ring. It should be noted that the monovalent organic group optionally has substituents. Preferably, the monovalent organic group is a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a monovalent organic group containing an epoxy group. Therefore, it is preferred that the above-mentioned R... 9 ~R 12 The same or different, being a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a monovalent organic group containing an epoxy group.

[0079] The aforementioned monovalent organic groups containing epoxy groups are organic groups containing at least one epoxy group (ethylene oxide ring). Examples include: groups formed by epoxidation of at least one double bond of a straight-chain or branched aliphatic hydrocarbon group with carbon-carbon double bonds, such as alkenyl groups; and groups formed by epoxidation of at least one double bond of a cyclic aliphatic hydrocarbon group with carbon-carbon double bonds (e.g., cycloalkenyl; cyclohexenylethyl, etc., cycloalkenylalkyl, etc.). More specifically, examples include: 1,2-epoxyethyl (epoxy group), 1,2-epoxypropyl, 2,3-epoxypropyl (glycidyl), 2,3-epoxy-2-methylpropyl (methylglycidyl), 3,4-epoxybutyl, 3-glycidyloxypropyl, 3,4-epoxycyclohexylmethyl, 2-(3,4-epoxycyclohexyl)ethyl, etc.

[0080] Examples of alkenyl groups include substituted or unsubstituted alkenyl groups such as vinyl, allyl, butenyl, pentenyl, and hexenyl. Examples of substituents include halogen atoms, hydroxyl groups, and carboxyl groups. Among these, ω-alkenyl groups (alkenyl groups with a carbon-carbon unsaturated double bond at the end) are preferred, ω-alkenyl groups with 2 to 6 carbon atoms are more preferred, and allyl groups are even more preferred.

[0081] In equation (iv), R 13 and R 14 "Same" or "different" refers to a hydrogen atom or a monovalent organic group. Examples of monovalent organic groups mentioned above include those identical to the monovalent organic groups in the aforementioned epoxide compounds containing isocyanuric acid rings.

[0082] Particularly preferred is R in equation (iv) 9 ~R 12 Whether the groups are the same or different, they are groups having groups shown in the following formula (iva) or groups having groups shown in the following formula (ivb), and R 9 ~R 12 At least one of them is a group having the group shown in formula (iva).

[0083]

[0084]

[0085] R in the above equations (iva) and (ivb) 15 and R 16 Whether the terms are the same or different, they refer to alkyl groups having 1 to 8 carbon atoms or hydrogen atoms. Examples of alkyl groups having 1 to 8 carbon atoms include straight-chain or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, pentyl, hexyl, heptyl, and octyl. Among these, straight-chain or branched alkyl groups having 1 to 3 carbon atoms, such as methyl, ethyl, propyl, and isopropyl, are preferred. R in formulas (iva) and (ivb) 15 and R 16 Hydrogen atoms are particularly preferred.

[0086] X in the above equations (iva) and (ivb) 3 and X 4 The terms "same" or "different" indicate divalent organic groups. These divalent organic groups can be divalent hydrocarbon groups, or groups formed by two or more divalent hydrocarbon groups bonded together by ester bonds, ether bonds, or other linking groups.

[0087] R in equation (iv) 9 ~R 12 Whether identical or different, it may have only one group having the group shown in formula (iva) above and / or a group having the group shown in formula (ivb) above, or it may have two or more. R9 ~R 12 The number of groups having the groups shown in the above formula (iva) and / or the groups having the groups shown in the above formula (ivb) is preferably 1 to 3, more preferably 1 to 2.

[0088] More specifically, examples of the above-mentioned epoxy compounds containing a glycourea ring include compounds shown in formula (iv-1), formula (iv-2), formula (iv-3), formula (iv-4), formula (iv-5), and formula (iv-6).

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095] In the above equations (iv-1) to (iv-6), R 15 R 16 X 3 and X 4 Same or different, as in formulas (iva) and (ivb).

[0096] Representative examples of compounds shown in formula (iv-1) above include 1,3,4,6-tetraglycidylglycerol, tetra(2-methylepoxypropyl)glycerol, etc.

[0097] Representative examples of compounds shown in formula (iv-2) above include: 1-allyl-3,4,6-triglycidylglycerol, 1-allyl-3,4,6-tris(2-methylepoxypropyl)glycerol, 1-(2-methylpropenyl)-3,4,6-triglycidylglycerol, 1-(2-methylpropenyl)-3,4,6-tris(2-methylepoxypropyl)glycerol, etc.

[0098] Representative examples of compounds shown in formula (iv-3) above include: 1,4-diallyl-3,6-diglycidyl glycourea, 1,4-diallyl-3,6-bis(2-methylepoxypropyl)glycourea, 1,4-bis(2-methylpropenyl)-3,6-diglycidyl glycourea, 1,4-bis(2-methylpropenyl)-3,6-bis(2-methylepoxypropyl)glycourea, etc.

[0099] Representative examples of compounds shown in formula (iv-4) above include: 1,3-diallyl-4,6-diglycidyl glycourea, 1,3-diallyl-4,6-bis(2-methylepoxypropyl)glycourea, 1,3-bis(2-methylpropenyl)-4,6-diglycidyl glycourea, 1,3-bis(2-methylpropenyl)-4,6-bis(2-methylepoxypropyl)glycourea, etc.

[0100] Representative examples of compounds shown in formula (iv-5) above include: 1,6-diallyl-3,4-diglycidyl glycourea, 1,6-diallyl-3,4-bis(2-methylepoxypropyl)glycourea, 1,6-bis(2-methylpropenyl)-3,4-diglycidyl glycourea, 1,6-bis(2-methylpropenyl)-3,4-bis(2-methylepoxypropyl)glycourea, etc.

[0101] Representative examples of compounds shown in formula (iv-6) above include: 1,3,4-triallyl-6-glycidylglycerol, 1,3,4-triallyl-6-(2-methylepoxypropyl)glycerol, 1,3,4-tris(2-methylpropenyl)-6-glycidylglycerol, 1,3,4-tris(2-methylpropenyl)-6-(2-methylepoxypropyl)glycerol, etc.

[0102] It should be noted that the above-mentioned epoxy compounds containing a glycourea ring can also be pre-modified by adding compounds that react with epoxy groups, such as alcohols and acid anhydrides, before use.

[0103] Relative to the total amount (100% by mass) of the curable epoxy composition, the content of the epoxy compound in the above-mentioned curable epoxy composition is preferably 10% by mass or more. In one embodiment of the above-mentioned curable epoxy composition (e.g., without inorganic fillers), the content of the epoxy compound is more preferably 60 to 99.5% by mass, more preferably 70 to 99% by mass, and even more preferably 75 to 98.5% by mass. In another embodiment of the above-mentioned curable epoxy composition (e.g., including inorganic fillers), the content of the epoxy compound is more preferably 10 to 50% by mass, more preferably 15 to 40% by mass, and even more preferably 18 to 30% by mass.

[0104] It should be noted that, in this specification, the content of each component (e.g., epoxy compound, photocationic polymerization initiator, etc.) contained in the above-described curable epoxy composition can be appropriately selected from the range described above in such a way that the total content is less than 100% by mass.

[0105] (Photocationic polymerization initiator)

[0106] Examples of photocationic polymerization initiators include: hexafluoroantimonate, pentafluorohydroxyantimonate, hexafluorophosphate, hexafluoroarsenate, tetra(pentafluorophenyl)borate, and pentafluoroethyl phosphate. Only one or more of these photocationic polymerization initiators may be used.

[0107] In addition, examples of photocationic polymerization initiators include: triarylsulfonium hexafluorophosphate (e.g., p-phenylthiophenyl diphenylsulfonium hexafluorophosphate), triarylsulfonium hexafluoroantimonate, and other sulfonium salts (especially triarylsulfonium salts); diaryliodomonium hexafluorophosphate, diaryliodomonium hexafluoroantimonate, bis(dodecylphenyl)iodomonium tetra(pentafluorophenyl)borate, iodomonium [4-(4-methylphenyl-2-methylpropyl)phenyl] hexafluorophosphate, and other iodomonium salts; tetrafluorophosphonium hexafluorophosphate and other phosphonium salts; N-hexylpyridinium tetrafluoroborate and other pyridinium salts.

[0108] Specifically, examples of photocationic polymerization initiators include: (4-hydroxyphenyl)methylbenzylsulfonium tetra(pentafluorophenyl)borate, 4-(4-biphenylthio)phenyl-4-biphenylphenylsulfonium tetra(pentafluorophenyl)borate, 4-(phenylthio)phenyl diphenylsulfonium phenyl tri(pentafluorophenyl)borate, [4-(4-biphenylthio)phenyl]-4-biphenylphenylsulfonium phenyl tri(pentafluorophenyl)borate, and diphenyl[4-(phenylthio)phenyl]sulfonium tri(pentafluoroethyl)trifluorophosphate. Diphenyl[4-(phenylthio)phenyl]sulfonium tetra(pentafluorophenyl)borate, diphenyl[4-(phenylthio)phenyl]sulfonium hexafluorophosphate, 4-(4-biphenylthio)phenyl-4-biphenylphenylsulfonium tri(pentafluoroethyl)trifluorophosphate, sulfide bis[4-(diphenylsulfonium)phenyl]phenyl tri(pentafluorophenyl)borate, [4-(2-thioxanthoneylthio)phenyl]phenyl-2-thioxanthoneylsulfonium tri(pentafluorophenyl)borate, 4-(phenylthio)phenyl diphenylsulfonium hexafluoroantimonate, etc.

[0109] The aforementioned photocationic polymerization initiators can be commercially available products. Examples of such commercially available products include: "CyracureUVI-6970", "CyracureUVI-6974", "CyracureUVI-6990", and "CyracureUVI-950" (manufactured by Union Carbide, Inc., USA); "Omnirad250", "Omnirad261", "Omnirad264", and "CG-24-61" (manufactured by IGM Resins, Inc.); "OptomerSP-150", "OptomerSP-151", "OptomerSP-170", and "OptomerSP-171" (manufactured by ADEKA, Inc.); and "DAICAT". II (manufactured by DAICEL Co., Ltd.); "UVAC1590", "UVAC1591" (manufactured by DAICEL-ALLNEX Co., Ltd.); "CI-2064", "CI-2639", "CI-2624", "CI-2481", "CI-2734", "CI-2855", "CI-2823", "CI-2758", "CIT-1682" (manufactured by Nippon Soda Co., Ltd.); "PI-2074" (manufactured by Rhodia Co., Ltd., tetra(pentafluorophenyl)borate toluene-cumyl iodomonium salt); "FF C509 (manufactured by 3M); "BBI-102", "BBI-101", "BBI-103", "MPI-103", "TPS-103", "MDS-103", "DTS-103", "NAT-103", "NDS-103" (manufactured by Midori Chemical Co., Ltd.); "CD-1010", "CD-1011", "CD-1012" (manufactured by Sartomer, Inc., USA); "CPI-100P", "CPI-101A" (manufactured by San-Apro Co., Ltd.), etc.

[0110] The content of the above-mentioned photocationic polymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 7 parts by mass, and even more preferably 0.5 to 4 parts by mass, relative to the total amount (100 parts by mass) of the cationic curable compound in the curable epoxy composition. If the content is 0.01 parts by mass or more, photocuring is easier to perform, and photocationic polymerization can be carried out in a short time. If the content is 10 parts by mass or less, the storage stability is better.

[0111] (Polyols)

[0112] The aforementioned curable epoxy composition may also contain polyols. By incorporating polyols, the cured product obtained from the curable epoxy composition exhibits a high glass transition temperature and improved flexibility. Consequently, the heat resistance of the cured product of the aforementioned curable epoxy composition is improved. Furthermore, the addition of polyols allows the reaction to proceed more slowly. Only one type of polyol may be used, or two or more types may be used.

[0113] The aforementioned polyols are compounds having two or more hydroxyl groups within their molecules. Examples of such polyols include: aliphatic polyols, alicyclic polyols, aromatic polyols, polyether polyols, polyester polyols, polycarbonate polyols, and polyolefin polyols. Among these polyols, polyester polyols are preferred from the viewpoint of further improving the glass transition temperature and flexibility of the cured product.

[0114] Examples of the aforementioned polyester polyols include compounds having two or more hydroxyl groups and two or more ester bonds within their molecules. Examples of the aforementioned polyester polyols include: polycaprolactone polyols and other polylactone polyols, aliphatic polyester polyols, aromatic polyester polyols, and alicyclic polyester polyols.

[0115] Of the aforementioned polyester polyols, from the viewpoint of maintaining a high glass transition temperature of the cured product and exhibiting superior flexibility, polylactone polyols and / or aliphatic polyester polyols are preferred. Furthermore, from the same viewpoint, polyester diols and / or polyester triols are also preferred as the aforementioned polyester polyols.

[0116] The molecular weight of the aforementioned polyols (especially polyester polyols) is not particularly limited, but is preferably 250 or more, more preferably 600 or more, even more preferably 1100 or more, and particularly preferably 1700 or more. If the molecular weight is 250 or more (especially 600 or more), the strength and toughness of the cured product are easily improved, and the flexibility is further enhanced. The aforementioned molecular weight can be, for example, 100,000 or less, or 50,000 or less, 10,000 or less, or 4,000 or less. The molecular weight of the aforementioned polyol refers to the number-average molecular weight converted from standard polystyrene, determined by gel permeation chromatography (GPC).

[0117] The hydroxyl value of the aforementioned polyols (especially polyester polyols) is not particularly limited, but is preferably 600 mg / g or less, more preferably 200 mg / g or less, even more preferably 100 mg / g or less, and particularly preferably 80 mg / g or less. If the hydroxyl value is 600 mg / g or less (especially 200 mg / g or less), the chain transfer reaction of the epoxy compound polymerization is suppressed, the degree of polymerization of the epoxy backbone easily increases, and the glass transition temperature of the cured product can be maintained at a high level. The aforementioned hydroxyl value can be determined by potentiometric titration according to JIS K0070.

[0118] When the above-mentioned curable epoxy composition contains polyols, the proportion of polyols in the curable epoxy composition is not particularly limited, but is preferably 1 to 40% by mass relative to the total amount (100% by mass), more preferably 3 to 30% by mass, and even more preferably 5 to 20% by mass. If the above proportion is within the above range, the heat resistance and flexibility of the cured product are excellent. In particular, the proportion of polyester polyols is preferably within the above range.

[0119] (Inorganic filler)

[0120] The aforementioned curable epoxy composition may also contain inorganic fillers. By incorporating inorganic fillers, the sedimentation of any powders that may be present in the composition can be suppressed by imparting thixotropy to the composition; furthermore, it can impart low linear expansion to the cured product. Only one type of inorganic filler may be used, or two or more may be used.

[0121] As the aforementioned inorganic filler, known or conventional inorganic fillers can be used without particular limitation, such as: silicon dioxide, alumina, zircon, calcium silicate, calcium phosphate, calcium carbonate, magnesium carbonate, silicon carbide, silicon nitride, aluminum nitride, boron nitride, aluminum hydroxide, iron oxide, zinc oxide, zirconium oxide, magnesium oxide, titanium oxide, alumina, calcium sulfate, barium sulfate, forsterite, steel, spinel, clay, kaolin, dolomite, hydroxyapatite, nepheline syenite, quartz, wollastonite, diatomaceous earth, talc, etc., in powder form or in shaped form (e.g., spherical beads). Furthermore, the aforementioned inorganic fillers may or may not be surface-treated. Moreover, as surface-treated inorganic fillers, examples include inorganic fillers obtained by subjecting the aforementioned inorganic fillers to known or conventional surface treatments. Among these, from the viewpoint that the coefficient of linear expansion of the cured product is lower and the warping of the cured product is less likely to occur, silica, alumina, and aluminum nitride are preferred as inorganic fillers, and silica (silica filler) is more preferred.

[0122] There are no particular limitations on the silica used; for example, known or conventional silica such as molten silica, crystalline silica, and high-purity synthetic silica can be used. It should be noted that silica obtained by performing known or conventional surface treatments (e.g., surface treatment using surface treatment agents such as metal oxides, silane coupling agents, titanium coupling agents, organic acids, polyols, and organosilicones) can also be used.

[0123] Hydrophilic silica and hydrophobic silica are examples of silica. From the viewpoint that it can easily increase the viscosity of curable epoxy compositions, inhibit the sedimentation of solid components such as microencapsulated latent curing agents and improve dispersibility, and impart thixotropy to curable epoxy compositions, as well as excellent workability such as impregnation and injection molding, hydrophobic silica is preferred.

[0124] The aforementioned hydrophobic silica is silica obtained by hydrophobizing hydrophilic silica. Examples of processing agents used for hydrophobication treatment include: methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, hexamethyldisilazane, methyltrialkoxysilane, dimethyldialkoxysilane, trimethylalkoxysilane, ethyltrichlorosilane, propyltrichlorosilane, hexyltrichlorosilane, long-chain alkyltrichlorosilane, ethyltrialkoxysilane, propyltrialkoxysilane, hexyltrialkoxysilane, long-chain alkyltrialkoxysilane, methacrylate silane, fluoroalkylsilane, perfluoroalkylsilane, and other organosilicon compounds; dimethylpolysiloxane (silicone oil), methylphenylpolysiloxane, methylhydropolysiloxane, amino-modified organosilicon, and other polysiloxane organosilicon compounds, etc. Among these, hydrophobication treatment of polysiloxanes is preferred. Hydrophobication treatment can be carried out using well-known methods, such as liquid phase method, gas phase method, autoclave method, etc.

[0125] The shape of silica is not particularly limited, and examples include: powder, spherical, broken, fibrous, needle-like, and flake-like. From the viewpoint of dispersibility, spherical silica is preferred, and perfectly spherical silica (e.g., spherical silica with an aspect ratio of 1.2 or less) is particularly preferred.

[0126] The specific surface area of ​​silica is not particularly limited, but from the viewpoint of imparting excellent workability such as thixotropy, impregnation, and injection molding properties to the cured epoxy composition, 10 μm is preferred. 2 / g or more, preferably 40m 2 / g or more, further preferably 70m 2 / g or more.

[0127] The center particle size of silica is not particularly limited, but from the viewpoint of imparting excellent workability such as thixotropy, impregnation, and injection molding properties to the cured epoxy composition, it is preferably 200 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less. The aforementioned center particle size is, for example, 3 nm or more. Furthermore, from the viewpoint of improving the low linear expansion, strength, and crack resistance of the cured product, it is preferably 0.1 to 50 μm, more preferably 0.1 to 30 μm. It should be noted that the aforementioned center particle size refers to the particle size at 50% of the integral value of the particle size distribution determined by laser diffraction / scattering (median particle size).

[0128] When the above-mentioned curable epoxy composition contains inorganic fillers, the content (compound amount) of inorganic fillers in the curable epoxy composition is not particularly limited. It is preferably 0.5 to 500 parts by mass relative to 100 parts by mass of the total amount of cationic curable compounds contained in the curable epoxy composition, more preferably 10 to 400 parts by mass, even more preferably 30 to 350 parts by mass, and particularly preferably 50 to 320 parts by mass. If the above content is within the above range, the viscosity of the curable epoxy composition increases appropriately, and the impregnation, molding, and other workability are improved.

[0129] When the above-mentioned curable epoxy composition contains inorganic fillers, the proportion of inorganic fillers in the curable epoxy composition is not particularly limited, but is preferably 0.5 to 95% by mass relative to the total amount (100% by mass) of the curable epoxy composition, more preferably 30 to 90% by mass, further preferably 40 to 85% by mass, and particularly preferably 45 to 80% by mass.

[0130] The above-described curable epoxy composition may also contain cationic curable compounds other than epoxy compounds. Relative to the total amount (100% by mass) of all the above-described curable compounds in the above-described curable epoxy composition, the content of epoxy compounds in the above-described curable epoxy composition and in the above-described cationic curable compounds is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, further preferably 80% by mass or more, further preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0131] Furthermore, the aforementioned curable epoxy compound preferably contains substantially no curable compounds other than cationic polymerizable compounds (other curable compounds). It should be noted that, in this specification, "substantially free" means not actively added, except in cases where their presence is unavoidable. Relative to the total amount of curable compounds contained in the curable epoxy composition (100% by mass), the proportion of the aforementioned other curable compounds in the aforementioned curable epoxy composition is preferably less than 1% by mass, more preferably less than 0.5% by mass, and even more preferably less than 0.1% by mass. By substantially containing no other curable compounds, it is less susceptible to curing hindrance caused by oxygen during photocuring, allowing for more complete curing.

[0132] Other examples of curable compounds mentioned above include anionic polymeric compounds and free radical polymeric compounds. Examples of free radical polymeric compounds include compounds having a (meth)acryloyl group (acryloyl group and / or methacryloyl group) and other compounds possessing a radioactive carbon-carbon double bond.

[0133] Relative to the total amount (100 parts by mass) of the curable compounds contained in the curable epoxy composition, the content of polyol in the curable epoxy composition is preferably 5 to 45 parts by mass, more preferably 10 to 35 parts by mass, and even more preferably 15 to 30 parts by mass. If the above content is within the above range, the heat resistance and flexibility of the cured product are excellent.

[0134] The above-described curable epoxy composition may also contain other components besides those listed above. As other components, for example, without impairing viscosity or transparency, the following commonly used additives may be used: silicone-based, fluorine-based, etc., defoamers; leveling agents; coupling agents such as silane coupling agents like γ-epoxypropoxypropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane; surfactants; flame retardants; colorants; antioxidants; ultraviolet absorbers; ionomers; colorants; phosphors (e.g., inorganic phosphor particles such as YAG-based phosphor particles and silicate-based phosphor particles); release agents; tackifiers; dispersants; rust inhibitors; corrosion inhibitors; freezing point depressants; abrasion-resistant additives, etc. Only one of the above-mentioned components may be used, or two or more may be used.

[0135] The above-described curable epoxy composition preferably contains substantially no curing agents other than the aforementioned photocationic polymerization initiator. The content of the aforementioned other curing agents is preferably less than 0.01 parts by weight, more preferably less than 0.005 parts by weight, relative to the total amount (100 parts by weight) of the cationic curable compound in the curable epoxy composition. By being substantially free of other curing agents, the curable epoxy composition exhibits excellent storage stability.

[0136] Other curing agents mentioned above include thermal cationic polymerization initiators, anionic polymerization initiators, free radical polymerization initiators, curing accelerators, and curing catalysts.

[0137] The above-mentioned curable epoxy composition is preferably liquid at 25°C. If the above-mentioned curable epoxy composition is liquid at 25°C, its workability, such as impregnation, molding, and filling properties, is excellent. The viscosity of the above-mentioned curable epoxy composition at 25°C is not particularly limited, but is preferably 330 mPa·s or higher (e.g., 330 mPa·s to 100,000 mPa·s). If the viscosity is 330 mPa·s or higher, the composition does not drip after impregnation, and there is a tendency for improved workability during impregnation and molding. If the viscosity is 100,000 mPa·s or lower, there is a tendency for improved impregnation and molding workability, or for less likelihood of defects originating from poor molding occurring in the cured product. It should be noted that the viscosity of the cured epoxy composition at 25°C can be measured, for example, using a digital viscometer (model "DVU-EII type", manufactured by Tokimec Co., Ltd.) under the following conditions: rotor: standard 1°34'×R24, temperature: 25°C, rotation speed: 0.5 to 10 rpm.

[0138] In one embodiment of the above-described curable epoxy composition (e.g., without inorganic fillers), the viscosity of the curable epoxy composition at 25°C is more preferably 400 mPa·s or more (e.g., 400 mPa·s to 10000 mPa·s), and even more preferably 450 mPa·s or more (e.g., 450 mPa·s to 1000 mPa·s). Furthermore, in another embodiment of the above-described curable epoxy composition (e.g., including inorganic fillers), the viscosity of the curable epoxy composition at 25°C is more preferably 2000 mPa·s or more (e.g., 2000 to 100000), 8000 mPa·s or more (e.g., 8000 mPa·s to 80000 mPa·s), and even more preferably 10000 mPa·s or more (e.g., 10000 mPa·s to 70000 mPa·s).

[0139] The above-described curable epoxy composition is not particularly limited and can be prepared by stirring / mixing the components under a heated state as needed. It should be noted that the above-described curable epoxy composition can be used as a single-liquid composition where the components are pre-mixed and used as is, or as a multi-liquid composition (e.g., a two-liquid composition) where two or more separately stored components are mixed before use. The stirring / mixing method is not particularly limited; for example, known or commonly used stirring / mixing units such as dissolvers, homogenizers, and various mixers; kneaders; rollers; bead mills; and self-rotating / revolutionary stirring devices can be used. Furthermore, defoaming can be performed under vacuum after stirring / mixing.

[0140] The curable epoxy composition disclosed herein can cure rapidly in the presence of oxygen and exhibits excellent filling properties. Therefore, when coating components with complex structures using the curable epoxy composition, liquid dripping is less likely to occur during curing. Furthermore, surface tackiness is reduced early on, resulting in excellent workability. In addition, the rapid curing time helps reduce CO2 emissions and environmental impact.

[0141] [Cured product]

[0142] A cured product can be obtained by curing the above-mentioned curable epoxy composition. The above-mentioned curable composition has both photocurable and thermocurable properties, so it is preferable to perform photocuring and thermocuring sequentially. First, photocuring is performed, thereby suppressing liquid dripping and stickiness (viscousness) after the curable epoxy composition is applied, resulting in excellent workability. Then, thermocuring is performed, thereby enabling thermocuring to be carried out in a short time.

[0143] When applying the above-described curable epoxy composition, known or conventional methods can be used. When applying the above-described curable epoxy composition to components such as coils or semiconductors in rotating electric machines with complex shapes, the substrate to be coated can be immersed in the above-described curable epoxy composition. After immersion, the substrate is lifted from the above-described curable epoxy composition and photocured by irradiation with active energy rays.

[0144] Examples of such active energy rays include ionizing rays such as alpha rays, beta rays, gamma rays, neutron beams, and electron beams; and ultraviolet radiation. The irradiation conditions for active energy rays are appropriately set according to the type of active energy ray; for example, an illuminance of 5–300 mW / cm². 2 The irradiation dose is 50–18000 mJ / cm². 2 The irradiation time is preferably 10 seconds to 5 minutes, more preferably 20 seconds to 1 minute.

[0145] After photocuring, thermal curing is performed. The temperature during thermal curing (curing temperature) is not particularly limited, but is preferably 45°C to 200°C, more preferably 50°C to 190°C, and even more preferably 55°C to 180°C. Furthermore, the heating time during curing (curing time) is not particularly limited, but is preferably 5 to 60 minutes, more preferably 10 to 45 minutes. By performing thermal curing after photocuring, the above-described curable epoxy composition can shorten the thermal curing time, and even with the above-mentioned curing time, a cured product with high degree of curing can be obtained. Moreover, each curing step can be performed in one step, or in multiple steps (two or more steps).

[0146] The glass transition temperature (Tg-DMA) of the cured product is preferably 78°C or higher, more preferably 80°C or higher, and even more preferably 100°C or higher. If the glass transition temperature is 78°C or higher, the heat resistance is excellent.

[0147] The glass transition temperature (Tg-TMA) of the cured product is preferably 40°C or higher, more preferably 50°C or higher, and even more preferably 60°C or higher. If the glass transition temperature is 40°C or higher, the heat resistance is excellent.

[0148] In one embodiment (e.g., without inorganic fillers), the elastic modulus of the cured material at 25°C is preferably 1.0 to 10.0 GPa, more preferably 2.0 to 6.0 GPa, and even more preferably 3.0 to 5.0 GPa. Furthermore, in another embodiment (e.g., including inorganic fillers), the elastic modulus of the cured material at 25°C is preferably 12.0 to 30.0 GPa, more preferably 14.0 to 28.0 GPa, and even more preferably 16.0 to 26.0 GPa. If the elastic modulus is above the lower limit, it is easier to follow the movement of the adhered object, such as a rotating motor or semiconductor, resulting in better adhesion. If the elastic modulus is below the upper limit, the internal stress becomes more appropriate. The elastic modulus can be determined by viscoelasticity measurement.

[0149] In one embodiment (e.g., without inorganic fillers), the coefficient of linear expansion (α1) of the cured material in the low-temperature region below Tg is preferably 90 ppm / ℃ or less (e.g., 20 to 90 ppm / ℃), more preferably 80 ppm / ℃ or less (e.g., 30 to 80 ppm / ℃), and even more preferably 70 ppm / ℃ or less (e.g., 40 to 70 ppm / ℃). Furthermore, in another embodiment (e.g., including inorganic fillers), the coefficient of linear expansion (α1) is preferably 200 ppm / ℃ or less (e.g., 5 to 200 ppm / ℃), more preferably 100 ppm / ℃ or less (e.g., 7 to 100 ppm / ℃), and even more preferably 30 ppm / ℃ or less (e.g., 10 to 30 ppm / ℃). If the coefficient of linear expansion (α1) is below the aforementioned upper limit, it is less prone to deformation due to temperature changes, resulting in excellent coating properties on the adhered object.

[0150] In one embodiment (e.g., without inorganic fillers), the coefficient of linear expansion (α2) of the cured material in a high-temperature region above Tg is preferably 220 ppm / ℃ or less (e.g., 60 to 220 ppm / ℃), more preferably 200 ppm / ℃ or less (e.g., 70 to 200 ppm / ℃), and even more preferably 180 ppm / ℃ or less (e.g., 100 to 180 ppm / ℃). Furthermore, in another embodiment (e.g., including inorganic fillers), the coefficient of linear expansion (α2) is preferably 90 ppm / ℃ or less (e.g., 20 to 90 ppm / ℃), more preferably 85 ppm / ℃ or less (e.g., 30 to 85 ppm / ℃), and even more preferably 80 ppm / ℃ or less (e.g., 40 to 80 ppm / ℃). If the coefficient of linear expansion (α2) is below the aforementioned upper limit, it is less prone to deformation due to temperature changes, resulting in excellent coating properties on the adhered object.

[0151] The above-described curable epoxy composition and cured product are used in parts contained in rotating electric machines (for rotating electric machine applications) and / or in semiconductor applications. The cured product exhibits excellent heat resistance, making it preferably suitable for parts used in high-temperature environments, particularly automotive parts (such as EV motors for automobiles). Specific applications of the cured product include: insulating materials, coating materials, and adhesive materials. The above-described curable epoxy composition demonstrates excellent wettability, impregnation, and filling properties to the object to be coated. Therefore, the above-described curable epoxy composition is preferably used in atmospheric pressure impregnation, depressurized pressure impregnation, pressurized impregnation, and immersion processes.

[0152] Examples of applications for the aforementioned rotating electric motors include: protection of rotor wires (winding covering, tip covering, etc.), impregnation / molding of stator coils, impregnation / molding to cover the entire stator, magnet fixing to fix a magnet inserted into a hole in the rotor core or stator core to the inner wall of the hole, and filling the gap between the hole and the magnet.

[0153] Regarding the use of the above-mentioned curable epoxy composition and the above-mentioned cured product, coil impregnation applications, such as coil (wire, winding) impregnation / molding applications in the stator and rotor of rotating electric machines, are preferred.

[0154] By using the aforementioned cured material for the aforementioned applications of rotary motors, rotary motors with rotors or stators comprising the aforementioned cured material can be obtained, for example: a rotary motor rotor comprising a rotor winding covered by the aforementioned cured material; a rotary motor stator comprising the aforementioned cured material formed in a manner covering stator coils; a rotary motor stator comprising the aforementioned cured material covering the entire stator; a rotary motor rotor or stator comprising a rotor core or stator core having a hole, a magnet inserted into the hole, and the aforementioned magnet being bonded to the inner wall of the hole; a rotary motor rotor or stator comprising a rotor core or stator core having a hole, a magnet inserted into the hole, and the aforementioned cured material filling the gap between the magnet and the inner wall of the hole, etc.

[0155] Examples of semiconductor applications include sealing and underfilling. By using the cured material for these semiconductor applications, the curable epoxy composition can be cured quickly in the presence of oxygen, thus suppressing thermal damage to the semiconductor. Furthermore, the semiconductor is particularly preferably a power semiconductor. Power semiconductors require higher insulation than conventional semiconductors, but because the curable epoxy composition is less prone to dripping, it can be easily coated to form a thick film, providing sufficient insulation.

[0156] The various solutions disclosed in this specification can also be combined with any other features disclosed in this specification. The structures and combinations of structures in the various embodiments are merely examples, and appropriate additions, omissions, substitutions, and other modifications to the structures can be made without departing from the spirit of this disclosure. Furthermore, the inventions of this disclosure are not limited to the embodiments or the following examples, but only to the claims.

[0157] Example

[0158] The following describes one embodiment of the present disclosure in more detail based on an example.

[0159] Example 1

[0160] (Preparation of the curable composition)

[0161] Using the proportions shown in Table 1 (unit: parts by mass), an alicyclic epoxy compound (trade name "CELLOXIDE2021P", manufactured by DAICEL Co., Ltd.), a polyester polyol (trade name "PLACCEL220", manufactured by DAICEL Co., Ltd.), and diphenyl[4-(phenylthio)phenyl]sulfonium tri(pentafluoroethyl) trifluorophosphate (curing agent A) as a UV cationic polymerization initiator were added to an ointment container and mixed evenly using a rotary stirring device (trade name "AWATORI RENTARO AR-250", manufactured by THINKY Co., Ltd.) to further defoam and produce a curable composition that is liquid at 25°C.

[0162] (Preparation of solidified material)

[0163] The curable composition obtained above was filled into a mold, held in place by a glass plate, and the illuminance was adjusted using a lux meter (trade name "UV lux meter UIT-201", manufactured by Ushio Electric Co., Ltd.). The surface was then irradiated with ultraviolet light under atmospheric conditions using a UV irradiation machine (trade name "San Ace120", manufactured by Sanyo Electric Co., Ltd.), followed by heat curing in an oven to produce a cured product. The irradiation conditions are shown in Table 2.

[0164] Examples 2-8, Comparative Example 1

[0165] (Preparation of the curable composition)

[0166] The composition of the curable epoxy composition was changed to that shown in Table 1. Otherwise, a curable composition that is liquid at 25°C was prepared in the same manner as in Example 1.

[0167] (Preparation of solidified material)

[0168] The cured composition obtained above was filled into a mold, clamped with a glass plate, and the illuminance was adjusted using a lux meter (trade name "UV lux meter UIT-201", manufactured by Ushio Electric Co., Ltd.). The surface was then irradiated with ultraviolet light under atmospheric conditions using a UV irradiation machine (trade name "San Ace120", manufactured by Sanyo Electric Co., Ltd.), followed by heat curing in an oven to produce a cured product. The irradiation conditions are shown in Table 2 or Table 3.

[0169] [Table 1]

[0170]

[0171] It should be noted that the ingredients used in the embodiments and comparative examples are as follows.

[0172] (Epoxy compounds)

[0173] CELLOXIDE 2021P: Trade name "CELLOXIDE 2021P", manufactured by DAICEL Co., Ltd., (3,4-epoxycyclohexylmethyl (3,4-epoxy)cyclohexylcarbamate).

[0174] TEPIC-FL: Trade name "TEPIC-FL", manufactured by Nissan Chemical Co., Ltd., a triepoxyisocyanurate compound.

[0175] TEPIC-UC: Trade name "TEPIC-UC", manufactured by Nissan Chemical Co., Ltd., a hexacyclic isocyanurate compound.

[0176] YX8000: Trade name "YX8000", manufactured by Mitsubishi Chemical Co., Ltd., is a hydrogenated bisphenol type diglycidyl compound.

[0177] jER806: Trade name "jER806", manufactured by Mitsubishi Chemical Co., Ltd., is a bisphenol F type epoxy resin.

[0178] YD128: Trade name "YD-128", manufactured by Nippon Steel Chemical & Material Co., Ltd., Bisphenol A diglycidyl ether.

[0179] (Polyols)

[0180] PCL: Trade name "PLACCEL 220", manufactured by DAICEL Co., Ltd., an aliphatic polyester glycol with a molecular weight of 2000 and a hydroxyl value of 56.8 KOH mg / g.

[0181] (Acrylic monomers)

[0182] Viscoat#230: Trade name "Viscoat#230", manufactured by Osaka Organic Chemical Industry Co., Ltd., 1,6-hexanediol diacrylate.

[0183] (additive)

[0184] Silica filler: Manufactured by DENKA Corporation, non-surface treated, with a central particle size of approximately 0.1–100 μm, and is perfectly spherical.

[0185] (UV cationic polymerization initiator)

[0186] Curing agent A: Diphenyl[4-(phenylthio)phenyl]sulfonium tri(pentafluoroethyl)trifluorophosphate.

[0187] Curing agent B: Triarylsulfonium salt.

[0188] (Free radical polymerization initiator)

[0189] Omnirad 184: Trade name "Omnirad 184", manufactured by IGM Resins, 1-hydroxycyclohexylphenyl ketone.

[0190] <Evaluation>

[0191] The following evaluation tests were performed on the curable compositions and cured products obtained in the Examples and Comparative Examples. It should be noted that the properties of the cured product of Comparative Example 1 were obtained by evaluating the cured product prepared by ultraviolet irradiation under a nitrogen flow instead of atmospheric pressure.

[0192] (Viscoelasticity determination)

[0193] For the cured material, viscoelasticity was measured using a solid viscoelasticity measuring apparatus (trade name "DMA7100", manufactured by Hitachi High-Tech Science Co., Ltd.) under nitrogen flow, a heating rate of 5°C / min, a measurement temperature range of -50 to 300°C, a deformation mode of tension, and a frequency of 1 Hz. The elastic modulus at 25°C was measured. Then, the inflection point of the obtained temperature thermal history curve was taken as the glass transition temperature (Tg-DMA).

[0194] (Thermomechanical analysis)

[0195] For the cured material, thermomechanical analysis was performed using a thermomechanical analysis apparatus (trade name "TMA 6100", manufactured by Hitachi High-Tech Science Co., Ltd.) under nitrogen flow, a heating rate of 5°C / min, and a measurement temperature of 30–300°C. The inflection point of the obtained temperature history curve was then taken as the glass transition temperature (Tg-TMA), and the coefficients of linear expansion (α1, α2) were calculated based on the curves before and after the glass transition temperature.

[0196] (Differential scanning calorimetry)

[0197] For the curable compositions of Examples 6-8, a differential scanning calorimeter (DSC6200, manufactured by Seiko Instruments Co., Ltd.) was used. Under a nitrogen flow, a UV irradiator (San Ace120, manufactured by Sanyo Electric Co., Ltd.) was installed, and ultraviolet irradiation was performed at 30°C and an intensity of 200 mW × 10 sec. After UV irradiation, differential scanning calorimetry was performed under a nitrogen flow, a heating rate of 10°C / min, and a measurement temperature range of 30–300°C. The degree of cure was then calculated by taking the heat release between the inflection point (glass transition temperature) and 300°C of the obtained temperature history curve as residual heat release.

[0198] (curing property (i))

[0199] After atmospheric ultraviolet irradiation during the production of cured materials, cases without poor curing are rated as "0", and cases with poor curing are rated as "×".

[0200] (curing property (ii))

[0201] For cured products that have undergone thermosetting during the production of cured products, cases without poor curing are rated as "0", and cases with poor curing are rated as "×".

[0202] (Operability)

[0203] After atmospheric ultraviolet irradiation during the production of cured materials, a case in which no liquid drips and no stickiness is produced is evaluated as "0", and a case in which liquid drips or becomes sticky is evaluated as "×".

[0204] [Table 2]

[0205]

[0206] [Table 3]

[0207]

[0208] As shown in Table 2, the curable compositions of Examples 1-5 can be cured by ultraviolet irradiation under atmospheric conditions, exhibiting excellent workability. Furthermore, they can be heat-cured within a short time of 30 minutes, resulting in excellent curing properties after heat curing. On the other hand, the curable composition of Comparative Example 1 does not cure sufficiently under ultraviolet irradiation under atmospheric conditions, resulting in poor workability. Moreover, because Comparative Example 1 did not cure sufficiently under ultraviolet irradiation under atmospheric conditions, it also exhibited insufficient curing when heat-cured for 30 minutes.

[0209] The curable compositions of Examples 6-8 are examples containing inorganic fillers. As shown in Table 3, they can be cured by ultraviolet irradiation under atmospheric conditions and exhibit excellent workability. Furthermore, they can be heat-cured in a short time of 15 minutes, and exhibit excellent curability after heat curing. In addition, the curable compositions of the examples are liquid at 25°C and also exhibit excellent filling and impregnation properties.

[0210] The following describes variations of the invention disclosed herein.

[0211] [Note 1] A curable epoxy composition comprising an epoxy compound having an intramolecular epoxy group and a photocationic polymerization initiator, said curable epoxy composition being used for rotary motor applications and / or semiconductor applications.

[0212] [Note 2] The curable epoxy composition according to Note 1, wherein the curable epoxy composition comprises an alicyclic epoxy compound as the epoxy compound.

[0213] [Note 3] The curable epoxy composition according to Note 1 or 2, wherein the curable epoxy composition comprises an aromatic epoxy compound as the epoxy compound.

[0214] [Note 4] The curable epoxy composition according to any one of Notes 1 to 3, wherein the curable epoxy composition comprises an aliphatic epoxy compound as the epoxy compound.

[0215] [Note 5] The curable epoxy composition according to any one of Notes 1 to 4, wherein the curable epoxy composition comprises a heterocyclic epoxy compound as the epoxy compound.

[0216] [Note 6] According to Note 5, the curable epoxy composition comprises an epoxy compound having an isocyanuric acid ring as the heterocyclic epoxy compound.

[0217] [Note 7] The curable epoxy composition according to Note 6, wherein the curable epoxy composition comprises a compound represented by formula (iii) as the epoxy compound having an isocyanuric acid ring.

[0218]

[0219] (In equation (iii), R) 4 ~R 6 The same or different indicates a hydrogen atom or a monovalent organic group. Among them, R... 4 ~R 6 At least one of them is a monovalent organic group containing an epoxy group.

[0220] [Note 8] The curable epoxy composition according to any one of Notes 5 to 7, wherein the curable epoxy composition comprises an epoxy compound having a glycourea ring as the heterocyclic epoxy compound.

[0221] [Note 9] The curable epoxy composition according to Note 8, wherein the curable epoxy composition comprises a compound of the following formula (iv) as the epoxy compound having a glycourea ring.

[0222]

[0223] (In formula (iv), R) 9 ~R 12 The same or different indicates a hydrogen atom or a monovalent organic group. Among them, R... 9 ~R 12 At least one of them is a monovalent organic group containing an epoxy group. Furthermore, R 13 and R 14 Same or different, indicating hydrogen atoms or monovalent organic groups).

[0224] [Note 10] The curable epoxy composition according to any one of Notes 1 to 9, wherein the content of the epoxy composition is 60 to 99.5% by mass relative to the total amount (100% by mass) of the curable epoxy composition.

[0225] [Note 11] The curable epoxy composition according to any one of Notes 1 to 10, wherein the curable epoxy composition is substantially free of curing agents other than the photocationic polymerization initiator.

[0226] [Note 12] The curable epoxy composition according to any one of Notes 1 to 11, wherein the curable epoxy composition comprises a polyol.

[0227] [Note 13] The curable epoxy composition according to Note 12, wherein the curable epoxy composition comprises a polyester polyol as the polyol.

[0228] [Note 14] The curable epoxy composition according to Note 12 or 13, wherein the molecular weight of the polyol is 600 or more and 50,000 or less.

[0229] [Note 15] The curable epoxy composition according to any one of Notes 12 to 14, wherein the hydroxyl value of the polyol is less than 600 KOH mg / g.

[0230] [Note 16] The curable epoxy composition according to any one of Notes 12 to 15, wherein the polyol is contained in an amount of 1 to 40% by mass relative to the total amount (100% by mass) of the curable epoxy composition.

[0231] [Note 17] The curable epoxy composition according to any one of Notes 1 to 16, wherein the epoxy compound is present in an amount of 90% by mass or more relative to the total amount of the cationic curable compound.

[0232] [Note 18] The curable epoxy composition according to any one of Notes 1 to 17, wherein the curable epoxy composition is substantially free of free radical polymerizable compounds.

[0233] [Note 19] The curable epoxy composition according to any one of Notes 1 to 18, wherein the curable epoxy composition comprises an inorganic filler.

[0234] [Note 20] The curable epoxy composition according to Note 19, wherein the curable epoxy composition comprises silica as the inorganic filler.

[0235] [Appendix 21] In the curable epoxy composition according to Appendix 20, the specific surface area of ​​the silica is 10 m². 2 / g or more.

[0236] [Note 22] The curable epoxy composition according to Note 20 or 21, wherein the central particle size of the silica is 3 nm or more and 200 nm or less.

[0237] [Note 23] The curable epoxy composition according to Note 20 or 21, wherein the central particle size of the silica is 0.1 to 30 μm.

[0238] [Note 24] In any one of Notes 20 to 23, the content of the inorganic filler is 0.5 to 500 parts by mass relative to 100 parts by mass of the total amount of cationic curable compound contained in the curable epoxy composition.

[0239] [Note 25] The curable epoxy composition according to any one of Notes 1 to 24, wherein the curable epoxy composition is liquid at 25°C.

[0240] [Appendix 26] The curable epoxy composition according to any one of Appendices 1 to 25, wherein the curable epoxy composition is a curable epoxy composition for impregnating the stator coil of the rotating electric motor, or a curable epoxy composition for fixing a magnet inserted into a hole provided in the rotor core of the rotating electric motor to the inner wall of the hole.

[0241] [Note 27] A cured product, which is a cured product of the curable epoxy composition according to any one of Notes 1 to 26.

[0242] [Note 28] A stator for a rotary electric machine, comprising a solidified material as described in Note 27 formed in a manner that covers the stator coils.

[0243] [Note 29] A rotor for a rotary electric motor, comprising a solidified material according to Note 27 for the windings of the covered rotor.

Claims

1. A curable epoxy composition comprising an epoxy compound having an intramolecular epoxy group and a photocationic polymerization initiator, said curable epoxy composition for use in rotary motors and / or semiconductor applications.

2. The curable epoxy composition according to claim 1, wherein, The curable epoxy composition substantially contains no curing agent other than the photocationic polymerization initiator.

3. The curable epoxy composition according to claim 1 or 2, wherein, The curable epoxy composition contains a polyol.

4. The curable epoxy composition according to claim 1 or 2, wherein, The epoxy compound accounts for more than 90% by mass of the total amount of the cationic curable compound.

5. The curable epoxy composition according to claim 1 or 2, wherein, The cured epoxy composition is substantially free of free radical polymerizable compounds.

6. The curable epoxy composition according to claim 1 or 2, wherein, The cured epoxy composition contains an inorganic filler.

7. The curable epoxy composition according to claim 1 or 2, wherein, The curable epoxy composition is liquid at 25°C.

8. The curable epoxy composition according to claim 1 or 2, wherein, The curable epoxy composition is a curable epoxy composition for impregnating the stator coil of the rotating electric motor, or a curable epoxy composition for fixing a magnet inserted into a hole in the rotor core of the rotating electric motor to the inner wall of the hole.

9. A cured product, which is a cured product of the curable epoxy composition according to claim 1 or 2.

10. A stator for a rotary electric motor, comprising a cured material according to claim 9 formed in a manner covering stator coils.

11. A rotor for a rotary electric motor, comprising a cured material according to claim 9, wherein the windings of the rotor are covered.

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