JP2023073098A - Curable composition - Google Patents

Abstract

To provide a curable composition excellent in electrical insulation properties.SOLUTION: The curable composition according to one embodiment of the present invention contains: a (meth)acrylic polymer (A); an epoxy compound and/or an oxetane compound (B); a photoradical polymerization initiator (C); and an epoxy curing agent (D). The weight ratio of the (meth)acrylic polymer (A) to the epoxy compound and/or the oxetane compound (B) is (1:99)-(50:50). The (meth)acrylic polymer (A) has a molecular weight distribution (Mw/Mn) of 1.8 or less, the total of bromine element and potassium element contained in the polymer is 0 ppm or more and 25 ppm or less, and the polymer has 1.0 or more groups represented by "-OC(O)C(R1)=CH2" per molecule. In the formula, R1 represents a hydrogen atom or a C1-20 organic group.SELECTED DRAWING: None

Description

The present invention relates to curable compositions.

Curable compositions containing (meth)acrylic polymers and epoxy compounds are known in the prior art. Patent Document 1 describes a method for purifying a vinyl polymer produced by atom transfer radical polymerization of a vinyl monomer. Patent Document 2 discloses a vinyl polymer having a specific terminal structure, an epoxy compound and/or an oxetane compound, and photoradical polymerization by a living radical polymerization method of a (meth)acrylic monomer using a copper complex as a catalyst. A curable composition comprising an initiator, a photocationic polymerization initiator, and a compound having an epoxy group and a (meth)acryloyl group in the molecule as essential components is described.

JP-A-2004-155846 WO2012/020545 WO2005/092981

However, the conventional techniques as described above have room for further improvement from the viewpoint of realizing a curable composition having excellent electrical insulation.

An object of one aspect of the present invention is to provide a curable composition having excellent electrical insulation.

The curable composition according to one aspect of the present invention is
(Meth) acrylic polymer (A);
an epoxy compound and/or an oxetane compound (B);
a radical photopolymerization initiator (C);
an epoxy curing agent (D);
contains
The weight ratio of the (meth)acrylic polymer (A) to the epoxy compound and/or oxetane compound (B) is (1:99) to (50:50),
The (meth)acrylic polymer (A) is
The molecular weight distribution (Mw/Mn) is 1.8 or less,
The total amount of bromine element and potassium element contained in the polymer is 0 ppm or more and 25 ppm or less, and
It has 1.0 or more (meth)acryloyl-based functional groups represented by the following general formula (a) per molecule.
—OC(O)C(R ¹ )=CH ₂ General formula (a)
(In the formula, R ¹ represents a hydrogen atom or an organic group having 1 to 20 carbon atoms).

An aspect of the present invention provides a curable composition with excellent electrical insulation.

An embodiment of the invention will be described below, but the invention is not limited thereto. In this specification, unless otherwise specified, "A to B" representing a numerical range means "A or more and B or less". As used herein, "(meth)acryl" means acryl and/or methacryl.

[1. (Meth)acrylic polymer (A)]
A curable composition according to one embodiment of the present invention contains a (meth)acrylic polymer (A). Only one kind of the (meth)acrylic polymer (A) may be used, or two or more kinds thereof may be used in combination.

[1.1. Main chain of (meth)acrylic polymer]
The (meth)acrylic monomer constituting the main chain of the (meth)acrylic polymer (A) is not particularly limited. Examples of (meth)acrylic monomers include (meth)acrylic acid and (meth)acrylic acid esters. Examples of (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and n-(meth)acrylate. Butyl, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, (meth)acrylic n-heptyl acid, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, (meth)acrylate Phenyl Acrylate, Toluyl (Meth)acrylate, Benzyl (Meth)acrylate, 2-Methoxyethyl (Meth)acrylate, 3-Methoxybutyl (Meth)acrylate, 2-Hydroxyethyl (Meth)acrylate , 2-hydroxypropyl (meth)acrylate, stearyl (meth)acrylate, glycidyl (meth)acrylate, 2-aminoethyl (meth)acrylate, γ-(methacryloyloxypropyl)trimethoxysilane, (meth) Ethylene oxide adduct of acrylic acid, trifluoromethyl (meth)acrylate, 2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl (meth)acrylate, 2-perfluoro(meth)acrylate Ethyl-2-perfluorobutylethyl, 2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate, diperfluoromethylmethyl (meth)acrylate, 2-perfluoromethyl (meth)acrylate -2-perfluoroethylmethyl, 2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl (meth)acrylate, and 2-perfluorohexadecylethyl (meth)acrylate.

Based on the physical properties of the resulting (meth)acrylic polymer (A), among these monomers, acrylic acid esters and methacrylic acid esters are preferred, acrylic acid esters are more preferred, and n-butyl acrylate is preferred. , ethyl acrylate and 2-methoxyethyl acrylate are more preferred.

The (meth)acrylic polymer (A) may be composed of units derived from only one type of these monomers, or may be composed of units derived from two or more types of monomers. The (meth)acrylic polymer (A) may be a copolymer of units derived from the preferred monomers described above and units derived from other monomers. In this case, the proportion of units derived from preferred monomers in the (meth)acrylic polymer (A) is preferably 20% by weight or more, more preferably 50% by weight or more, and even more preferably 70% by weight or more.

[1.2. (Meth)acryloyl functional group possessed by the (meth)acrylic polymer (A)]
The (meth)acrylic polymer (A) has 1.0 or more (meth)acryloyl functional groups represented by the following general formula (a) per molecule. In the formula, R ¹ represents a hydrogen atom or an organic group having 1 to 20 carbon atoms. Since the (meth)acrylic polymer (A) has a (meth)acryloyl substituent, it is cured by light irradiation.
—OC(O)C(R ¹ )=CH ₂ General formula (a)

The (meth)acryloyl functional group represented by the general formula (a) may be located in the middle of the main chain of the (meth)acrylic polymer (A), or may be located at the end of the main chain. may From the viewpoint of rubber elasticity to be obtained, the (meth)acryloyl functional group is preferably located at the end of the main chain.

In the general formula (a), examples of the structure of R ¹ include -H, -CH ₃ , -CH ₂ CH ₃ , -(CH ₂ ) _n CH ₃ (n represents an integer of 2 to 19), - C ₆ H ₅ (phenyl group), —CH ₂ OH, —CN are included. From the viewpoint of the reactivity of the (meth)acryloyl functional group, R ¹ is preferably —H or —CH ₃ .

The number of (meth)acryloyl functional groups possessed by the (meth)acrylic polymer (A) is preferably 1.2 or more per molecule, more preferably 1.5 or more, and 1.8. The above is more preferable. The upper limit of the number of (meth)acryloyl functional groups possessed by the (meth)acrylic polymer (A) is, for example, 2.0 or less, 2.5 or less, or 3.0 or less per molecule. can be

[1.3. (Meth) molecular weight distribution of acrylic polymer (A)]
The (meth)acrylic polymer (A) has a molecular weight distribution of 1.8 or less. As used herein, molecular weight distribution represents the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn). Weight average molecular weight and number average molecular weight are measured by gel permeation chromatography (GPC). In one embodiment, the mobile phase used in GPC measurements is chloroform or tetrahydrofuran. In one embodiment, the column used for GPC measurements is a polystyrene gel column. The value of molecular weight is obtained as a polystyrene equivalent value.

The number average molecular weight of the (meth)acrylic polymer (A) is not particularly limited. The lower limit of the number average molecular weight is preferably 500 or more, more preferably 3,000 or more, even more preferably 5,000 or more, most preferably 8,000 or more. The upper limit of the number average molecular weight is preferably 1,000,000 or less, more preferably 100,000 or less, even more preferably 80,000 or less, most preferably 50,000 or less. If the number average molecular weight is too low, it tends to be difficult to exhibit properties such as tensile physical properties required of the (meth)acrylic polymer (A). If the number average molecular weight is too high, the polymer tends to be difficult to handle.

The molecular weight distribution of the (meth)acrylic polymer (A) is preferably 1.7 or less, more preferably 1.6 or less, even more preferably 1.5 or less, and particularly preferably 1.4. or less, and most preferably 1.3 or less. The theoretical lower limit of the molecular weight distribution is one.

[1.4. (Meth) Ionic Element Contained in Acrylic Polymer (A)]
The (meth)acrylic polymer (A) has a reduced content of ionic elements. As used herein, ionic elements mean bromine and potassium. These ionic elements are basically mixed during the synthesis of the main chain of the (meth)acrylic polymer (A). However, the potassium element is also mixed when the functional group is introduced.

The total amount of bromine element and potassium element contained in the (meth)acrylic polymer (A) is 25 ppm or less. The total amount of bromine element and potassium element contained in the (meth)acrylic polymer (A) is preferably 20 ppm or less, more preferably 15 ppm or less, and even more preferably 10 ppm or less, from the viewpoint of electrical insulation. The bromine element and the potassium element are inevitably included in the synthesis of the (meth)acrylic polymer (A), so the lower limit of the total content of these elements is more than 0 ppm. This lower limit may be, for example, 0.1 ppm or 0.5 ppm. If the total amount of elemental bromine and elemental potassium is within the above range, the resulting cured product exhibits good electrical insulation.

Among elemental bromine and elemental potassium, the (meth)acrylic polymer (A) tends to contain more elemental bromine than elemental potassium. Therefore, by reducing the amount of bromine element contained in the (meth)acrylic polymer (A), the ionic element contained in the (meth)acrylic polymer (A) can be efficiently reduced. The amount of bromine element contained in the (meth)acrylic polymer (A) is preferably 15 ppm or less, more preferably 10 ppm or less, and even more preferably 5 ppm or less. This lower limit may be, for example, 0.1 ppm or 0.5 ppm.

The content of ionic elements is measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS).

In order to reduce the ionic element content of the (meth)acrylic polymer (A), for example, it is preferable to provide a purification step in the production process of the (meth)acrylic polymer (A). Examples of objects to be removed in the purification process include solvents (polymerization solvents, etc.) and insoluble components (polymerization catalysts, etc.). Examples of specific treatments in the purification process include liquid-liquid extraction using water and adsorption treatment using an adsorbent. In order to improve purification efficiency, heat treatment may be performed in the purification step.

Another example of the method for reducing the ionic element content of the (meth)acrylic polymer (A) is chemical modification. Specifically, there is a method of removing a bromine group contained in a polymer molecule by introducing a functional group.

For a more detailed description of the purification process, see, for example, [0040] to [0066] of JP-A-2004-002835 and [0117]-[0143] of JP-A-2013-241541.

As a specific example of a preferable production method for reducing the ionic element content of the (meth)acrylic resin (A), before the step of introducing the (meth)acryloyl functional group, the [0040] to [0066] perform adsorption filtration purification; after the step of introducing a (meth)acryloyl functional group, perform water purification described in [0117] to [0143] of JP-A-2013-241541. method. A more detailed manufacturing method will be described in a manufacturing example described later.

[2. Method for producing (meth)acrylic polymer (A)]
[2.1. Main chain manufacturing method]
The (meth)acrylic polymer (A) has a molecular weight distribution (Mw/Mn) of 1.8 or less. In order to achieve such a small molecular weight distribution, it is preferable to produce the (meth)acrylic polymer (A) by living polymerization. Examples of living polymerization include living radical polymerization, living anionic polymerization, and living cationic polymerization. Living radical polymerization is preferred from the viewpoint of raw material management, facility design, and manufacturing process. Examples of living radical polymerization include ATRP (atom transfer radical polymerization), ARGET, ICAR, SET-LRP, RAFT and NMP. ATRP and ARGET are preferred from the viewpoint of ease of raw material procurement and purification. Each method will be briefly described below.

[2.1.1. ATRP]
Examples of initiators used in ATRP include organic halides, sulfonyl halide compounds. Among the organic halides, organic halides having a highly reactive carbon-halogen bond are more preferable (carbonyl compounds having a halogen at the α-position, compounds having a halogen at the benzylic position, etc.). Specific examples of initiators are described in paragraphs [0040] to [0064] of JP-A-2005-232419.

As the initiator, a compound having two or more initiation points is preferred. By using such an initiator, it is easy to control the molecular structure of the (meth)acrylic resin (A) to be produced to a preferred one. Specifically, it is easy to obtain a (meth)acrylic resin (A) having a (meth)acryloyl functional group at the end of the molecule and having 1.0 or more functional groups per molecule. .

The (meth)acrylic monomer used in ATRP is not particularly limited. Any of the (meth)acrylic acid ester monomers exemplified in section [1] can be suitably used.

The transition metal complex used as a polymerization catalyst in ATRP is not particularly limited. Preferred are metal complexes having an element of Group 7, 8, 9, 10 or 11 of the periodic table as the central metal. More preferred are transition metal complexes having zerovalent copper, monovalent copper, divalent ruthenium, divalent iron, or divalent nickel as a central metal. More preferably, it is a complex having monovalent copper as a central metal. Examples of monovalent copper compounds used to form such complexes include cuprous chloride, cuprous bromide, cuprous iodide, cuprous cyanide, cuprous oxide, perchlorate Cuprous acid may be mentioned.

When a metal complex having monovalent copper as a central metal is used as a polymerization catalyst, it is preferable to use a polydentate amine as a ligand because the catalytic activity is enhanced. Examples of polydentate amines include 2,2'-bipyridine or its derivatives, 1,10-phenanthroline or its derivatives, tetramethylethylenediamine, pentamethyldiethylenetriamine, hexamethyltris(2-aminoethyl)amine.

The ATRP polymerization reaction can be carried out in the absence of a solvent or in the presence of a solvent. Examples of solvents used for polymerization are described in [0067] of JP-A-2005-232419. Only one solvent may be used, or two or more solvents may be used in combination. The polymerization reaction can also be carried out in an emulsion system or a system mediated by supercritical fluid _CO2 .

The polymerization temperature in ATRP is preferably 0 to 200°C, more preferably room temperature (eg, 20°C) to 150°C.

[2.1.2. ARGET]
ARGET is an aspect of ATRP. Since ARGET regenerates the metal catalyst by using a reducing agent, the amount of metal catalyst used can be greatly reduced. Therefore, the purification load after production is also reduced, leading to cost reduction.

In one embodiment, ARGET uses monovalent copper, polydentate amines, bases other than polydentate amines, and reducing agents. In this polymerization system, monovalent copper coordinated with a polydentate amine functions as a polymerization catalyst. Bases other than polydentate amines have the function of removing acid, which is a by-product of the catalytic cycle, and preventing poisoning of polydentate amines. The reducing agent reduces the divalent copper complex to an active monovalent copper complex. By controlling the rate of addition of the reducing agent, the rate of polymerization and the heat of polymerization can be controlled.

In a preferred embodiment of ARGET, 5 to 30 ppm by weight of copper atoms are used with respect to the total charge of (meth)acrylic monomers. In this embodiment, the amount of polydentate amine used is 7 mmol% or less with respect to the entire polymerization system, and 150 mol% or less with respect to the total amount of copper atoms. This polymerization system also contains a base and a reducing agent other than the polydentate amine.

(polydentate amine)
Examples of polydentate amines include: Only one type of polydentate amine may be used, or two or more types may be used in combination.
- Bidentate polydentate amines: 2,2-bipyridine, 4,4'-di-(5-nonyl)-2,2'-bipyridine, N-(n-propyl)pyridylmethanimine, N-( n-octyl)pyridylmethanimine/tridentate polydentate amines: N,N,N′,N″,N″-pentamethyldiethylenetriamine, N-propyl-N,N-di(2-pyridylmethyl) ) Amine/tetradentate polydentate amine: hexamethyltris(2-aminoethyl)amine, N,N-bis(2-dimethylaminoethyl)-N,N'-dimethylethylenediamine, 2,5,9, 12-tetramethyl-2,5,9,12-tetraazatetradecane, 2,6,9,13-tetramethyl-2,6,9,13-tetraazatetradecane, 4,11-dimethyl-1,4, 8,11-tetraazabicyclohexadecane, N',N''-dimethyl-N',N''-bis((pyridin-2-yl)methyl)ethane-1,2-diamine, tris[(2-pyridyl ) methyl]amine, 2,5,8,12-tetramethyl-2,5,8,12-tetraazatetradecane and pentadentate polydentate amine: N,N,N',N'',N''',N'''',N''''-heptamethyltetraethylenetetramine/hexadentate polydentate amine: N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine/polyamine : Polyethyleneimine

Preferred polydentate amines are hexamethyltris(2-aminoethyl)amine and N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine. When these polydentate amines are used, a sufficient reaction rate can be achieved while reducing the amount of transition metal atoms used (about 30 ppm or less relative to the (meth)acrylic monomer). Moreover, the molecular weight distribution of the obtained (meth)acrylic resin becomes narrow.

(Bases other than polydentate amines)
Bases other than polydentate amines may be Bronsted bases (compounds that accept protons) or Lewis bases (compounds that donate unshared electron pairs to form coordinate bonds). Examples of bases other than polydentate amines include the following. Bases other than polydentate amines may be used alone or in combination of two or more.
• Monoamines: Monoamines refer to compounds with only one amine site that acts as a base. Specific examples of monoamines include primary amines (methylamine, aniline, lysine, etc.), secondary amines (dimethylamine, piperidine, etc.), tertiary amines (trimethylamine, triethylamine, etc.), aromatic amines (pyridine, pyrrole, etc.), Ammonia is mentioned.
- Inorganic base: An inorganic base represents an element or compound of Group 1 or Group 2 of the periodic table. Examples of elements include lithium, sodium, and calcium. Examples of compounds include sodium methoxide, potassium ethoxide, methyllithium, sodium hydroxide, potassium hydroxide, potassium carbonate, sodium hydrogen carbonate, ammonium hydrogen carbonate, trisodium phosphate, disodium hydrogen phosphate, triphosphate Potassium, dipotassium hydrogen phosphate, sodium acetate, potassium acetate, sodium oxalate, potassium oxalate, sodium phenoxy, potassium phenoxy, sodium ascorbate, potassium ascorbate. In addition to these, salts of weak acids (such as ammonium hydroxide) and strong bases are also inorganic bases.

Bases other than polydentate amines may be added directly to the reaction system or may be generated in the reaction system.

Bases other than the polydentate amine are usually removed by purification after the production of the (meth)acrylic polymer (A). Therefore, amines with low boiling points or low cost are preferred. Examples of amines satisfying such conditions include triethylamine and trimethylamine.

(reducing agent)
Examples of reducing agents are described in [0083] to [0095] of WO2012/020545. Only one reducing agent may be used, or two or more reducing agents may be used in combination.

The reducing agent is usually removed by purification after production of the (meth)acrylic polymer (A). Therefore, reducing agents that are easy to purify or that are low cost are preferred. Examples of reducing agents satisfying such conditions include ascorbic acid, ascorbates, and organic tin compounds.

The lower limit of the amount of the reducing agent to be added is preferably 10 ppm or more with respect to the total amount of (meth)acrylic acid monomer charged. The upper limit of the amount of the reducing agent added is preferably 100000 ppm or less, more preferably 10000 ppm or less, even more preferably 1000 ppm or less, and particularly preferably 500 ppm or less, relative to the total amount of (meth)acrylic acid monomer charged. If the addition amount of the reducing agent is within the above range, sufficient polymerization activity can be expected, and removal by purification is easy.

When the reducing agent is a substance that is solid at room temperature, it is preferable to add a solution of the reducing agent dissolved in a good solvent to the polymerization system. By doing so, it becomes easier to exhibit the effect as a reducing agent.

As mentioned above, the rate of polymerization and the heat of polymerization can be controlled by adjusting the rate of addition of the reducing agent. From the viewpoint of safety, it is preferable to add the reducing agent to the polymerization system little by little as the polymerization progresses. The lower limit of the addition rate of the reducing agent is preferably 10 mol %/Hr or more, more preferably 20 mol %/Hr or more, and even more preferably 30 mol %/Hr or more with respect to the copper complex. The upper limit of the addition rate of the reducing agent is preferably 1000 mol %/Hr or less, more preferably 700 mol %/Hr or less, and even more preferably 500 mol %/Hr or less, relative to the copper complex.

[2.2. Method for introducing a (meth)acryloyl functional group]
A known method can be used to introduce the (meth)acryloyl functional group represented by the general formula (a) into the main chain of the (meth)acrylic polymer. Such a method is described, for example, in [0080] to [0091] of JP-A-2004-203932.

In particular, a method of substituting a terminal halogen group of a (meth)acrylic polymer represented by the following general formula (b) with a compound having a (meth)acryloyl functional group represented by the following general formula (c): preferable. This method allows easy control of the reaction.

—CR ² R ³ X General formula (b)
In the formula, ^R2 and ^R3 are groups bonded to the ethylenically unsaturated groups of the (meth)acrylic monomer. X represents chlorine, bromine or iodine.

M ⁺⁻ OC(O)C(R ¹ )=CH ₂ General formula (c)
In the formula, R ¹ is as explained for general formula (a). M ⁺ represents an alkali metal ion or a quaternary ammonium ion. Examples of alkali metal ions include lithium ions, sodium ions and potassium ions. Examples of quaternary ammonium ions include tetramethylammonium ion, tetraethylammonium ion, tetrabenzylammonium ion, trimethyldodecylammonium ion, tetrabutylammonium ion, and dimethylpiperidinium ion. Preferred M ⁺ is one or more selected from sodium ions and potassium ions.

[2.1.1. ] Section using an organic halide or a sulfonyl halide compound as an initiator and a transition metal complex as a catalyst, a (meth)acrylic polymer having a terminal structure represented by the general formula (b) can be produced. . Alternatively, a (meth)acrylic polymer having a terminal structure represented by general formula (b) can be produced using a halogen compound as a chain transfer agent. The former production method is preferred.

When the compound represented by the general formula (c) is reacted with the polymer represented by the general formula (b), the amount of the oxyanion in the general formula (c) relative to the halogen group in the general formula (b) is preferably 1.0 to 5.0 equivalents, more preferably 1.0 to 1.2 equivalents.

The solvent used for the introduction reaction is preferably a polar solvent. This is because the introduction reaction is a nucleophilic substitution reaction. Examples of polar solvents include tetrahydrofuran, dioxane, diethyl ether, acetone, dimethylsulfoxide, dimethylformamide, dimethylacetamide, hexamethylphosphoric triamide, acetonitrile.

The reaction temperature for the introduction reaction is preferably 0 to 150°C. From the viewpoint of maintaining the polymerizability of the (meth)acryloyl functional group, the reaction temperature is more preferably room temperature (eg, 20°C) to 100°C.

[3. epoxy compound and/or oxetane compound (B)]
A curable composition according to one embodiment of the present invention contains an epoxy compound and/or an oxetane compound (B). Epoxy compounds and oxetane compounds play a role in improving the strength of cured products. The oxetane compound also serves to reduce the viscosity of the curable composition to improve workability. The epoxy compound and/or oxetane compound (B) may be used alone or in combination of two or more.

[3.1. epoxy compound]
Epoxy compounds generally refer to compounds having an epoxy group. Examples of epoxy compounds include aromatic epoxy compounds and alicyclic epoxy compounds. From the viewpoint of increasing the hardness of the cured product, aromatic epoxy compounds are preferred.

Furthermore, the epoxy compound preferably has a radical reactive group. Such epoxy compounds form crosslinks with the (meth)acryloyl functional groups of the (meth)acrylic polymer. Therefore, a tough cured product with low elution into solvents can be obtained. Examples of radically reactive groups include acryloyl, methacryloyl and allyl groups. Epoxy compounds having a radical reactive group are available from Nippon Kayaku Co., Ltd., DIC Co., Ltd., Showa Denko Materials Co., Ltd., and the like.

Specific examples of aromatic epoxy compounds include bisphenol A epoxy compounds, bisphenol F epoxy compounds, bisphenol AD epoxy compounds, hydrogenated bisphenol A epoxy compounds, and hydrogenated bisphenol F epoxy compounds. An example of an aromatic epoxy compound is 2,2-bis(4-glycidyloxyphenyl)propane.

Examples of alicyclic epoxy compounds include compounds having a cyclohexene oxide group, a tricyclodecene oxide group, a cyclopentene oxide group, and the like. More specific examples of alicyclic epoxy compounds include vinylcyclohexene diepoxide, vinylcyclohexene monoepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 2-(3, 4-epoxycyclohexyl 5,5-spiro-3,4-epoxy)cyclohexane-m-dioxane, bis(3,4-epoxycyclohexyl)adipate, bis(3,4-epoxycyclohexylmethylene)adipate.

[3.2. Oxetane compound]
Examples of oxetane compounds include 3-ethyl-3-hydroxymethyloxetane, 3-(meth)allyloxymethyl-3-ethyloxetane, (3-ethyl-3-oxetanylmethoxy)methylbenzene, 4-fluoro-[1 -(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 4-methoxy-[1-(3-ethyl-3-oxetanylmethoxy)methyl]benzene, [1-(3-ethyl-3-oxetanylmethoxy)ethyl ] Phenyl ether, isobutoxymethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyl (3-ethyl-3-oxetanylmethyl) ether, 2 - Ethylhexyl (3-ethyl-3-oxetanylmethyl) ether, Ethyldiethylene glycol (3-ethyl-3-oxetanylmethyl) ether, Dicyclopentadiene (3-ethyl-3-oxetanylmethyl) ether, Dicyclopentenyloxyethyl (3 -ethyl-3-oxetanylmethyl) ether, dicyclopentenylethyl (3-ethyl-3-oxetanylmethyl) ether, tetrahydrofurfuryl (3-ethyl-3-oxetanylmethyl) ether, tetrabromophenyl (3-ethyl-3 -oxetanylmethyl) ether, 2-tetrabromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, tribromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tribromophenoxyethyl (3-ethyl- 3-oxetanylmethyl) ether, 2-hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether, butoxyethyl (3-ethyl-3-oxetanylmethyl) ether ) ether, pentachlorophenyl (3-ethyl-3-oxetanylmethyl) ether, pentabromophenyl (3-ethyl-3-oxetanylmethyl) ether, bornyl (3-ethyl-3-oxetanylmethyl) ether, 3,7-bis (3-oxetanyl)-5-oxa-nonane, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 1,2-bis[(3-ethyl-3-oxetanylmethoxy)methyl ] ethane, 1,2-bis[(3-ethyl-3-oxetanylmethoxy)methyl]propane, ethylene glycol bis(3-ethyl-3-oxetanylmethyl)ether, dicyclopentenylbis(3-ethyl-3-oxetanyl methyl) ether, triethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tricyclodecanediyldimethylene bis (3-ethyl-3- oxetanylmethyl) ether, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]butane, 1,6-bis[(3-ethyl-3-oxetanylmethoxy)methyl]hexane, polyethylene glycol bis(3 -ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol A bis(3-ethyl-3-oxetanylmethyl) ether, PO-modified bisphenol A bis(3-ethyl-3-oxetanylmethyl) ether, EO-modified hydrogenated bisphenol A Bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol F bis (3-ethyl-3-oxetanylmethyl) ether, tri Methylolpropane tris(3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tris(3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis(3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis(3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol tetrakis(3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis(3-ethyl-3-oxetanylmethyl)ether, ditrimethylolpropanetetrakis(3-ethyl-3-oxetanylmethyl)ether.

The weight ratio of the (meth)acrylic polymer (A) to the epoxy compound and/or oxetane compound (B) in the curable composition is preferably 1:99 to 50:50, more preferably 2:98 to 40:60. Preferred is 3:97 to 30:70. If the blending ratio of the two is within the above range, the cured product will have sufficient strength and elongation.

[4. Photoradical polymerization initiator (C)]
A curable composition according to one embodiment of the present invention contains a radical photopolymerization initiator (C). The radical photopolymerization initiator (C) plays a role of curing the curable composition with light irradiation (such as UV irradiation) as a trigger. Only one kind of radical photopolymerization initiator (C) may be used, or two or more kinds thereof may be used in combination.

Examples of photoradical polymerization initiators (C) include acetophenone, propiophenone, benzophenone, xanthol, fluoresin, benzaldehyde, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-methylacetophenone, 3-pentyl Acetophenone, 2,2-diethoxyacetophenone, 4-methoxyacetophenone, 3-bromoacetophenone, 4-allylactophenone, p-diacetylbenzene, 3-methoxybenzophenone, 4-methylbenzophenone, 4-chlorobenzophenone, 4,4' -dimethoxybenzophenone, 4-chloro-4'-benzylbenzophenone, 3-chloroxanthone, 3,9-dichloroxanthone, 3-chloro-8-nonylxanthone, benzoyl, benzoin methyl ether, benzoin butyl ether, bis(4 -dimethylaminophenyl)ketone, benzylmethoxyketal, 2-chlorothioxanthone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2 -methyl-1-phenyl-propan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4 -morpholinophenyl)-butanone-1,2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one).

Further examples of radical photopolymerization initiators (C) include acylphosphine oxide photopolymerization initiators. Acylphosphine oxide-based photopolymerization initiators are preferable because they are excellent in deep-part curability during UV irradiation. Examples of acylphosphine oxide photoinitiators include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxy benzoyl)-2,4,4-trimethyl-pentylphosphine oxide, bis(2,6-dimethylbenzoyl)-phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-isobutylphosphine oxide, bis(2,6 -dimethoxybenzoyl)-isobutylphosphine oxide, bis(2,6-dimethoxybenzoyl)-phenylphosphine oxide. Among these are 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4, 4-trimethyl-pentylphosphine oxide is preferred.

Among the radical photopolymerization initiators (C) described above, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2, 2-dimethoxy-1,2-diphenylethan-1-one, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide are preferred.

The amount of the radical photopolymerization initiator (C) is 0.01 to 5 parts by weight, with the total weight of the (meth)acrylic polymer (A) and the epoxy compound and/or oxetane compound (B) being 100 parts by weight. Part by weight is preferable, and 0.05 to 1 part by weight is more preferable from the viewpoint of achieving both deep curability and light transmittance of the cured product.

[5. Epoxy Curing Agent (D)]
The curable composition contains an epoxy curing agent (D). Conventionally known epoxy curing agents (D) can be widely used. Examples of epoxy curing agents (D) include amine curing agents, imidazole curing agents, and acid anhydride curing agents. Only one type of epoxy curing agent (D) may be used, or two or more types may be used in combination.

Examples of amine curing agents include aliphatic amines (diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, hexamethylenediamine, methylpentamethylenediamine, trimethylhexamethylenediamine, guanidine, oleylamine, etc.); Cyclic amines (mencenediamine, isophoronediamine, norbornanediamine, piperidine, N,N'-dimethylpiperazine, N-aminoethylpiperazine, 1,2-diaminocyclohexane, bis(4-amino-3-methylcyclohexyl)methane, bis(4-aminocyclohexyl)methane, polycyclohexylpolyamine, 1,8-diazabicyclo[5,4,0]undecene-7 (DBU), etc.); amines having an ether bond (3,9-bis(3-aminopropyl )-2,4,8,10-tetraoxaspiro[5,5]undecane (ATU), morpholine, N-methylmorpholine, polyoxypropylenediamine, polyoxypropylenetriamine, polyoxyethylenediamine, etc.); hydroxyl-containing amines ( diethanolamine, triethanolamine, etc.); aromatic amines (tris-2,4,6-dimethylaminomethylphenol, etc.); aminosilanes (γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltri isopropoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ -(2-aminoethyl)aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltriisopropoxysilane, γ-(2-(2 -aminoethyl)aminoethyl)aminopropyltrimethoxysilane, γ-(6-aminohexyl)aminopropyltrimethoxysilane, 3-(N-ethylamino)-2-methylpropyltrimethoxysilane, 2-aminoethylaminomethyl trimethoxysilane, N-cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane , N-phenylaminomethyltrimethoxysilane, N-benzyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-γ-aminopropyltriethoxysilane, N-(3-triethoxysilylpropyl)-4,5- dihydroimidazole, N-cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane, N-phenylaminomethyltrimethoxysilane, (2-aminoethyl)aminomethyltrimethoxysilane, N,N'-bis[ 3-(trimethoxysilyl)propyl]ethylenediamine and the like; and ketimine-type silanes (N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine and the like).

Examples of imidazole curing agents include 2-phenylimidazole, 2-ethyl-4(5)-methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2- phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2, 4-diamino-6-[2′-methylimidazolyl-(1′)]-ethyl-s-triazine, 2,4-diamino-6-[2′-ethyl-4′-methylimidazolyl-(1′)] -ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanurate, 2-phenylimidazole isocyanurate, 2-phenyl -4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole. An adduct of an epoxy compound and the imidazole compound described above is also an example of an imidazole-based curing agent.

Examples of acid anhydride curing agents include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, dodecyl Succinic anhydride is mentioned.

Further examples of the epoxy curing agent (D) include polyamidoamines (polyamide obtained by reacting dimer acid and polyamine (diethylenetriamine, triethylenetetramine, etc.), and polycarboxylic acid other than dimer acid and polyamine reacted. modified amines (epoxy-modified amines obtained by reacting amines with epoxy compounds, Mannich-modified amines obtained by reacting amines with formalin or phenolic compounds, Michael addition-modified amines, ketimine, etc.); mentioned.

From the viewpoint of the curability of the epoxy compound and/or the oxetane compound (B), the epoxy curing agent (D) is preferably an amine-based curing agent. Furthermore, considering the storage stability of the curable composition, the epoxy curing agent (D) is preferably a tertiary amine compound.

The amount of the epoxy curing agent (D) is preferably 1 to 200 parts by weight, more preferably 5 to 100 parts by weight, based on 100 parts by weight of the epoxy compound and/or the oxetane compound (B). When the amount of the epoxy curing agent (D) is within the above range, the curability of the curable composition can be enhanced and the elution of components from the cured product can be reduced.

[6. Other ingredients]
The curable composition according to one embodiment of the present invention may contain various additives in addition to (A) to (D) described above, depending on the purpose. Examples of additives include polymerizable monomers and/or oligomers, fillers, plasticizers, solvents, thixotropic agents, antioxidants, and other additives. These additives may be used alone or in combination of two or more.

[6.1. Polymerizable monomers and/or oligomers]
Addition of a polymerizable monomer and/or oligomer can, for example, lower the viscosity of the curable composition, improve the curability, and improve the mechanical properties of the cured product. Examples of polymerizable monomers and/or oligomers include substances described in [0110] to [0124] of JP-A-2006-274085.

The blending amount of the polymerizable monomer and/or oligomer is preferably 10 to 200 parts by weight, more preferably 20 to 150 parts by weight, relative to 100 parts by weight of the (meth)acrylic polymer (A). , more preferably 30 to 100 parts by weight. If the blending amount is within the above range, there is an advantage that workability is improved by reducing the viscosity. Only one kind of the polymerizable monomer and/or oligomer may be used, or two or more kinds thereof may be used in combination.

[6.2. filler]
Addition of a filler can adjust the thixotropy of the curable composition and impart mechanical strength and abrasion resistance to the cured product. Examples of fillers include fillers and fine hollow particles described in [0134] to [0151] of JP-A-2006-291073.

Specific examples of fillers include finely divided silica that is reinforcing silica (fumed silica, wet silica, etc.), carbon black, wood flour, pulp, cotton chips, mica, walnut shell powder, rice husk powder, graphite, and white clay. , silica (crystalline silica, fused silica, dolomite, anhydrous silicic acid, hydrated silicic acid, etc.), ground calcium carbonate, colloidal calcium carbonate, magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, titanium oxide, bentonite, organic Bentonite, ferric oxide, red iron oxide, fine aluminum powder, flint powder, zinc oxide, active zinc white, zinc dust, zinc carbonate, shirasu balloons, beads (made of polyacrylic resin, polyacrylonitrile-vinylidene chloride resin, phenolic resin made of polystyrene resin, etc.) and their hollow particles, inorganic hollow particles (glass balloons, shirasu balloons, fly ash balloons, etc.), fibrous fillers (glass fiber, glass filament, carbon fiber, Kevlar fiber, polyethylene fiber, etc.) is mentioned. Among these, one or more selected from the group consisting of fumed silica, wet-process silica, carbon black, ground calcium carbonate, and hard calcium carbonate are preferred from the viewpoint of excellent reinforcing properties.

The particle size of fumed silica and wet-process silica is preferably 50 μm or less. The specific surface area of fumed silica and wet-process silica is preferably 80 m ² /g or more. Such fumed silica and wet process silica can sufficiently enhance reinforcing properties. As used herein, the specific surface area value represents a value measured by the BET method. Silica used as a filler is preferably surface-untreated silica rather than surface-treated silica (for example, silica surface-treated with organosilane, organosilazane, diorganocyclopolysiloxane, etc.). Surface-untreated silica has advantages such as easy kneading, good fluidity of the curable composition, and excellent economic efficiency.

Examples of commercially available fumed silica include AEROSIL (manufactured by Nippon Aerosil Co., Ltd.). Examples of commercially available wet process silica include Nipsil (manufactured by Tosoh Silica Co., Ltd.).

Examples of carbon black include channel black, furnace black, acetylene black and thermal black. Furnace black is preferred from the viewpoint of reinforcement and economy.

The amount of filler compounded is preferably 0.1 to 500 parts by weight, more preferably 0.5 to 200 parts by weight, based on 100 parts by weight of the (meth)acrylic polymer (A). It is preferably 1 to 50 parts by weight. If the blending amount is within the above range, both reinforcing properties of the cured product and workability of the curable composition can be achieved. Only one type of filler may be used, or two or more types may be used in combination.

[6.3. Plasticizer]
By adding a plasticizer, the viscosity of the curable composition can be adjusted, and the mechanical properties (tensile strength, elongation, etc.) of the cured product can be adjusted. Addition of a plasticizer can also improve the transparency of the cured product.

Examples of plasticizers include phthalates (dibutyl phthalate, diheptyl phthalate, di(2-ethylhexyl) phthalate, butylbenzyl phthalate, etc.); aromatic esters of polyalkylene glycols (diethylene glycol dibenzoate, triethylene glycol dibenzoate, etc.). ); phosphoric acid ester (tricresyl phosphate, tributyl phosphate, etc.); trimellitic acid ester; pyromellitic acid ester; polystyrene resin (polystyrene, poly-α-methylstyrene, etc.); polybutadiene; polybutene; polyisobutylene; butadiene-acrylonitrile; polychloroprene; chlorinated paraffin; Ether polyols (polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc.), derivatives obtained by converting hydroxyl groups of polyether polyols into ester groups or ether groups, etc.); Epoxy plasticizers (epoxidized soybean oil, epoxy benzyl stearate, etc.) (Meth)acrylic polymers obtained by polymerizing vinyl monomers by various methods (such as acrylic plasticizers; commercially available products include ARUFON series (manufactured by Toagosei Co., Ltd.)).

The blending amount of the plasticizer is preferably 1 to 100 parts by weight, more preferably 1 to 50 parts by weight, per 100 parts by weight of the (meth)acrylic polymer (A). When the blending amount is within the above range, the workability of the curable composition is good, and the influence on the mechanical properties of the obtained cured product is small. Only one plasticizer may be used, or two or more plasticizers may be used in combination.

[6.4. solvent]
Examples of solvents include aromatic hydrocarbon solvents (toluene, xylene, etc.); ester solvents (ethyl acetate, butyl acetate, amyl acetate, cellosolve acetate, etc.); ketone solvents (acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketones, etc.); alcohol solvents (methanol, ethanol, isopropanol, etc.); hydrocarbon solvents (hexane, cyclohexane, methylcyclohexane, heptane, octane, etc.).

The amount of the solvent compounded is preferably 50 parts by weight or less, more preferably 30 parts by weight or less, relative to 100 parts by weight of the (meth)acrylic polymer (A). When the blending amount is within the above range, the workability of the curable composition is good, and the influence of cure shrinkage is small. Moreover, from the viewpoint of little influence on the working environment, it is more preferably 10 parts by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer (A). Only one solvent may be used, or two or more solvents may be used in combination.

[6.5. thixotropy-imparting agent]
Addition of a thixotropic agent (anti-sagging agent) can prevent sagging and improve workability.

Examples of thixotropic agents include hydrogenated castor oil derivatives, metal soaps having long-chain alkyl groups, ester compounds having long-chain alkyl groups, inorganic fillers (such as silica), and amide waxes.

The amount of the thixotropic agent is preferably 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, per 100 parts by weight of the (meth)acrylic polymer (A). If the blending amount is within the above range, the workability of the curable composition will be good. Only one type of thixotropic agent may be used, or two or more types may be used in combination.

[6.6. Antioxidant]
Addition of an antioxidant (antiaging agent) can improve the heat resistance of the cured product.

Examples of antioxidants include primary antioxidants (hindered phenol antioxidants, amine antioxidants, lactone antioxidants, ethanolamine antioxidants, etc.), secondary antioxidants (sulfur oxidizing agents, phosphorus-based oxidizing agents, etc.). Further examples of antioxidants include substances described in [0232] to [0235] of JP-A-2007-308692, and substances described in [0089] to [0093] of WO 2005/116134. be done.

The content of the antioxidant is preferably 0.1 to 5 parts by weight, more preferably 0.1 to 3 parts by weight, per 100 parts by weight of the (meth)acrylic polymer (A). If the blending amount is within the above range, the heat resistance effect is sufficiently exhibited, and there is no economic disadvantage.

[6.7. Other additives]
Examples of other additives include compatibilizers, curability modifiers, radical inhibitors, metal deactivators, antiozonants, phosphorus peroxide decomposers, lubricants, pigments, antifoaming agents, and foaming agents. agents, termite inhibitors, fungicides, ultraviolet absorbers, and light stabilizers. Further examples of other additives include JP-A-63-006041, JP-A-63-006003, JP-A-63-254149, JP-A-64-022904, JP-A-2001- Additives described in JP-A-072854 can be mentioned.

[7. Curing method]
The curable composition according to one embodiment of the present invention is cured by both radical photocuring and thermal curing.

Photoradical curing is curing initiated by irradiation with active energy rays (UV, electron beams, etc.). The active energy ray source can be appropriately selected according to the properties of the radical photopolymerization initiator (C). Examples of active energy ray sources include high-pressure mercury lamps, low-pressure mercury lamps, LEDs, electron beam irradiation devices, halogen lamps, light-emitting diodes, and semiconductor lasers.

Thermal curing is an effect initiated by heating. The thermosetting temperature is appropriately set according to the types of epoxy compound and/or oxetane compound (B), epoxy curing agent (D), and other additives. The thermosetting temperature is preferably 15 to 300°C, more preferably 15 to 250°C. Within the above temperature range, deterioration of the cured product due to heat can be prevented. A heating furnace, an oven, a heating conveyor, or the like can be used for heat curing.

[8. Application]
Since the curable composition according to one embodiment of the present invention has good electrical insulation, it is suitably used for electric/electronic parts, resist materials, and the like. However, it is not limited to these uses, and can be used for various uses.

Examples of electrical and electronic parts include electrical insulating materials (insulating coating materials for electric wires and cables, etc.), sealing materials, adhesives, adhesives, conformal coating agents, potting agents for electrical and electronic devices, packing, O-rings, and belts. mentioned. More specific examples include high-voltage thick-film resistors, hybrid IC circuit elements, HICs, electrical insulating parts, semi-conductive parts, conductive parts, modules, printed circuits, ceramic substrates, diodes, transistors, or bonding wires. buffer materials, coating materials for optical fibers for optical communication, transformer high-voltage circuits, printed circuit boards, high-voltage transformers with variable resistors, electrical insulating parts, solar cells (crystalline silicon solar cells, amorphous silicon solar cells, CI (G)S solar cells, perovskite solar cells, organic thin-film solar cells, dye-sensitized solar cells, GaAs solar cells, etc.), potting materials for flyback transformers for televisions, heavy electrical parts, weak electrical parts, back sealing of solar cells Sealing materials for circuits and substrates of electrical and electronic equipment.

Examples of resist materials include peripheral members of semiconductors and conductors. More specific examples include photomasks, photoresists, semiconductor surface protection tapes, dicing tapes, die bonding tapes, die bonding materials, interlayer insulating materials (build-up materials), photosensitive dry film resists, and liquid photosensitive resin materials. , interporter materials, package substrate materials, solder resists, semiconductor sealing resins, underfill materials, side-fill materials, printed circuit board materials, and modifiers for these materials.

Further examples of suitable applications include components that allow passage of light (ultraviolet, visible, infrared, X-rays, lasers, etc.). Examples include display peripheral members and UV inks for 3D printing. More specific examples include flat panel displays and their sealing materials; liquid crystal display device peripheral materials (light guide plates, prism sheets, polarizing plates, retardation plates, viewing angle correction films, front glass protective films in the field of liquid crystal displays , polarizer protective films or adhesives, adhesives or fillers between panels or films, liquid crystal films, etc.); color PDP (plasma display) sealing materials, antireflection films, optical correction films, front glass protective films or adhesives, adhesives or fillers between panels or films; molding materials for light-emitting elements used in light-emitting diode displays, sealing materials for light-emitting diodes (LEDs), protective films or adhesives for front glass, panels or Adhesive or filler between films; light guide plate, prism sheet, polarizer, retarder viewing angle correction film, polarizer protective film or adhesive in plasma addressed liquid crystal (PALC) displays, adhesive or between panels or films Fillers; front glass protective films or adhesives in organic EL (electroluminescence) displays, adhesives or fillers between panels or films; protective films or adhesives in organic TFT (organic thin film transistor) displays, between panels or films Adhesives or fillers; Various film substrates in field emission displays (FED), protective films or adhesives for front glass, adhesives or fillers between panels or films; Protective films or adhesives, between panels or films in electronic paper protective films or adhesives for touch panels, mobile phone displays, car navigation displays, adhesives or fillers between panels or films; peripheral materials for the above display devices.

[9. summary〕
The present invention includes the following aspects.
<1>
(Meth) acrylic polymer (A);
an epoxy compound and/or an oxetane compound (B);
a radical photopolymerization initiator (C);
an epoxy curing agent (D);
contains
The weight ratio of the (meth)acrylic polymer (A) to the epoxy compound and/or oxetane compound (B) is (1:99) to (50:50),
The (meth)acrylic polymer (A) is
The molecular weight distribution (Mw/Mn) is 1.8 or less,
The total amount of bromine element and potassium element contained in the polymer is 0 ppm or more and 25 ppm or less, and
Having 1.0 or more (meth)acryloyl functional groups per molecule represented by the following general formula (a),
—OC(O)C(R ¹ )=CH ₂ General formula (a)
(Wherein, R ¹ represents a hydrogen atom or an organic group having 1 to 20 carbon atoms)
Curable composition.
<2>
The curable composition according to <1>, wherein the (meth)acrylic polymer (A) has the (meth)acryloyl functional group at the terminal of the molecule.
<3>
The curable composition according to <1> or <2>, wherein the bromine element contained in the (meth)acrylic polymer (A) is 0 ppm or more and 15 ppm or less.
<4>
The curable composition according to any one of <1> to <3>, wherein the epoxy compound and/or the oxetane compound (B) is an aromatic epoxy compound.
<5>
The curable composition according to any one of <1> to <4>, wherein the epoxy compound and/or the oxetane compound (B) is an epoxy compound having a radical reactive group.
<6>
The curable composition according to any one of <1> to <5>, wherein the epoxy curing agent (D) is an amine compound.
<7>
A step of producing the (meth)acrylic polymer (A) using a copper complex, a polydentate amine, a base other than the polydentate amine, and a reducing agent;
The obtained (meth)acrylic polymer (A), the epoxy compound and/or oxetane compound (B), the photoradical polymerization initiator (C), and the epoxy curing agent (D) are mixed. and
The method for producing a curable composition according to any one of <1> to <6>.

In addition to the above aspects, the present invention further includes the following aspects.
<A1>
The (meth)acrylic polymer (A) may be produced by a living polymerization method.
<A2>
The living polymerization method may be a living radical polymerization method.

Specific examples of the present invention are shown below. However, the present invention is not limited to the following examples.

[Method for measuring physical properties of (meth)acrylic resin]
[1. Number average molecular weight and molecular weight distribution]
The number average molecular weight and molecular weight distribution (ratio of weight average molecular weight to number average molecular weight) were calculated by a standard polystyrene conversion method using gel permeation chromatography (GPC).

As the GPC column, a column filled with polystyrene crosslinked gel (shodex GPC K-804 and K-802.5, manufactured by Showa Denko KK) was used. Chloroform was used as the GPC solvent.

[2. Content of ionic element]
The content of ionic elements (bromine element and potassium element) was analyzed using ICP-MS (HP-4500, manufactured by Yokogawa Analytical Systems Corporation).

[3. Number of functional groups introduced in the functionalization step]
The number of functional groups introduced per polymer molecule was calculated based on concentration analysis by ¹ H-NMR and number average molecular weight. As an apparatus for NMR, ASX-400 (manufactured by Bruker) was used. Deuterated chloroform was used as a solvent for NMR.

[Production example of (meth)acrylic resin]
Reagents used in the production examples were obtained from mass-produced reagents and used without any treatment such as purification in consideration of industrialization.

[Production Example 1]
<1. Polymerization step>
1. 100 parts by weight of n-butyl acrylate, 20 parts by weight of methanol, 1.76 parts by weight of diethyl 2,5-dibromoadipate, and 955 ppm of triethylamine (Et3N) were charged and stirred at 45°C under a nitrogen stream. Triethylamine corresponds to amines other than polydentate amines.
2. Bromide mixed with 107 ppm copper(II) bromide, 109 ppm hexamethyltris(2-aminoethyl)amine (96% purity), and 0.43 parts by weight (0.54 parts by volume) methanol A copper solution was prepared. The copper content in the copper bromide solution is 30 ppm, and the content of hexamethyltris(2-aminoethyl)amine is equivalent to copper. Hexamethyltris(2-aminoethyl)amine corresponds to polydentate amines.
3. An ascorbic acid solution was prepared by mixing 17 ppm ascorbic acid and 0.10 parts by weight (0.13 parts by volume) of methanol. Ascorbic acid corresponds to a reducing agent.
4. Copper bromide solution and ascorbic acid solution were added to the reaction system to initiate the reaction. During the reaction, the ascorbic acid solution was appropriately added, and heating and stirring were continued so that the temperature of the reaction solution reached 45°C to 70°C.
5. 153 minutes after the initiation of polymerization, the reaction rate of n-butyl acrylate reached 94 mol %. At this point, the volatile matter was removed under reduced pressure to obtain a (meth)acrylic polymer X. The amount of ascorbic acid added to the reaction system up to this point was 432 ppm and the amount of methanol was 65.4 parts by weight (81.8 parts by volume).

The (meth)acrylic polymer X had a number average molecular weight of 21,200 and a molecular weight distribution of 1.10.

<2. Adsorption filtration purification step (1)>
6. The (meth)acrylic polymer X obtained in the polymerization step was diluted with 100 parts by weight of butyl acetate to prepare a polymer solution.
7. An adsorbent was added to the polymer solution, and the mixture was heated and stirred at about 100° C. for 1 hour. As adsorbents, Kyoward 700SEN (adsorbent/manufactured by Kyowa Chemical Industry Co., Ltd.) and Kyoward 500SH (adsorbent/manufactured by Kyokagaku Kogyo Co., Ltd.) were used in an amount of 1 part by weight each.
8. A polymer slurry solution containing insoluble components (adsorbent, etc.) was filtered to separate solid and liquid. This gave a clear polymer solution.

<3. Functionalization step>
9. 2.0 parts by weight of potassium acrylate, 0.3 parts by weight of tetrabutylammonium bromide, and 0.01 parts by weight of H-TEMPO were added to the polymer solution obtained in the adsorption filtration purification step (1).
10. Using an autoclave, the mixture was heated and stirred at an internal temperature of 120° C. for 2 hours. As a result, a (meth)acrylic polymer Y having terminal functional groups represented by "--OC(O)CH=CH ₂ " was obtained.

In the (meth)acrylic polymer Y, the number of terminal functional groups introduced was two per molecule.

<4a. Water purification process>
11a. 400 parts by weight of water was added to the polymer solution of (meth)acrylic polymer Y obtained in the functionalization step. After stirring for 5 minutes at an internal temperature of 80° C., the mixture was allowed to stand for 10 minutes. This process separated the solution into two phases, forming an upper organic phase (polymer solution) and a lower aqueous phase.
12a. The aqueous phase was removed from the bottom of the autoclave. Thereafter, the organic phase was devolatilized under reduced pressure at 130° C. to obtain a clear (meth)acrylic polymer (1).

The (meth)acrylic polymer (1) had a number average molecular weight of 21,800 and a molecular weight distribution of 1.11. The bromine element contained in the (meth)acrylic polymer (1) was 5 ppm, and the potassium element was 2 ppm.

[Production Example 2]
The polymerization step, the adsorption filtration purification step (1), and the functionalization step were performed in the same manner as in Production Example 1. The functionalization step was followed by the adsorption filtration purification step (2) shown below instead of the water purification step described above.

<4b. Adsorption filtration purification step (2)>
11b. An adsorbent was added to the polymer solution of the (meth)acrylic polymer Y obtained in the functionalization step, and the mixture was heated and stirred at 100° C. for 1 hour. As adsorbents, Kyoward 700SEN (manufactured by Kyowa Chemical Industry Co., Ltd.) and Kyoward 500SH (manufactured by Kyowa Chemical Industry Co., Ltd.) were used in an amount of 1 part by weight each.
12b. A polymer slurry solution containing insoluble components (adsorbents, etc.) was filtered. Thereafter, devolatilization was performed under reduced pressure at 130° C. to obtain a clear (meth)acrylic polymer (2).

The (meth)acrylic polymer (2) had a number average molecular weight of 21,900 and a molecular weight distribution of 1.12. The (meth)acrylic polymer (2) contained 20 ppm of elemental bromine and 11 ppm of elemental potassium. Therefore, the (meth)acrylic polymer (2) does not correspond to the (meth)acrylic polymer (A) referred to in this specification.

[Preparation of sample for evaluation]
A sample for physical property evaluation was produced by the following method.

[1. Preparation of curable composition]
Each component was added to a disposable cup according to the composition shown in Table 1 below and stirred with a spatula. Then, using a rotation/revolution mixer (Awatori Mixer, manufactured by Thinky Co., Ltd.), the mixture was stirred at 1600 rpm for 1.5 minutes and defoamed at 2200 rpm for 3 minutes. Thus, a curable composition was obtained.

Each component blended in the curable composition is as follows.
● (Meth) acrylic polymer (A)
・(Meth)acrylic polymer (1): obtained in Production Example 1 ・(Meth)acrylic polymer (2): obtained in Production Example 2 Epoxy compound and/or oxetane compound (B)
- Epoxy compound (B1): an epoxy compound having a glycidyl group and an acryloyl group - Epoxy compound (B2): 2,2-bis (4-glycidyloxyphenyl) propane (jER828, manufactured by Mitsubishi Chemical Corporation)
●Photoradical polymerization initiator (C)
- Photoradical polymerization initiator (C1): 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Omnirad1173, manufactured by IGM Resins BV)
・Photoradical polymerization initiator (C2): bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Ominirad819, manufactured by IGM Resins BV)
● Epoxy curing agent (D)
・ Epoxy curing agent (D1): Tris-2,4,6-dimethylaminomethylphenol (Ankamine K54, manufactured by EVONIK)

[2a. Preparation of sample for three-point bending test]
1. The curable composition was poured into a Teflon (registered trademark) mold (width 10 mm, length 100 mm, thickness 2 mm).
2. Preheating was performed at 80° C. for 20 minutes. Then, the curable composition was irradiated with UV light using a UV irradiation device (LIGHT HAMMER 6, manufactured by Fusion UV Systems). The irradiated light was light source: mercury lamp, peak illuminance: 250 mW/cm ² , integrated light quantity: 2,000 mJ/cm ² .
3. A cured product was obtained by heating at 150° C. for 60 minutes.

[2b. Preparation of sample for volume resistance measurement]
A cured product was prepared in the same manner as the sample for the three-point bending test, except that the size of the Teflon (registered trademark) mold was changed to 100 mm in width, 100 mm in length, and 2 mm in thickness.

[Method for evaluating physical properties of cured product]
[Three-point bending test]
A jig with an indenter radius of 5 mm and a fulcrum radius of 2 mm was used. The distance between the fulcrums was 32 mm. An autograph (AG-2000A, manufactured by Shimadzu Corporation) was used for the measurement. Measurement temperature: 23°C, strain rate: 2 mm/min.

[Volume resistivity]
Using R8340 ULTRA HIGH RESISTANCE METER (manufactured by ADVANTEST), volume resistivity was measured by a method based on JIS K6911. It can be said that the higher the volume resistivity, the better the electrical insulation.

From Table 1, the cured product containing the (meth)acrylic polymer (1) has a higher volume resistivity than the cured product containing the (meth)acrylic polymer (2), and has excellent electrical insulation. was The difference between (meth)acrylic polymer (1) and (meth)acrylic polymer (2) is the total content of ionic elements (bromine element and potassium element).

By comparing the examples and comparative examples, it was confirmed that even if the total content of bromine element and potassium element was reduced, the mechanical properties of the cured product were not affected. In addition, by comparing Examples and Comparative Examples with Reference Examples, it was found that even when a (meth)acrylic polymer with a reduced total content of bromine element and potassium element was blended, the mechanical properties of the cured product were improved. It was confirmed that there is

One aspect of the present invention can be used in the field of curable compositions.

Claims (7)

(Meth) acrylic polymer (A);
an epoxy compound and/or an oxetane compound (B);
a radical photopolymerization initiator (C);
an epoxy curing agent (D);
contains
The weight ratio of the (meth)acrylic polymer (A) to the epoxy compound and/or oxetane compound (B) is (1:99) to (50:50),
The (meth)acrylic polymer (A) is
The molecular weight distribution (Mw/Mn) is 1.8 or less,
The total amount of bromine element and potassium element contained in the polymer is 0 ppm or more and 25 ppm or less, and
Having 1.0 or more (meth)acryloyl functional groups per molecule represented by the following general formula (a),
—OC(O)C(R ¹ )=CH ₂ General formula (a)
(Wherein, R ¹ represents a hydrogen atom or an organic group having 1 to 20 carbon atoms)
Curable composition. The curable composition according to claim 1, wherein the (meth)acrylic polymer (A) has the (meth)acryloyl functional group at the terminal of the molecule. The curable composition according to claim 1 or 2, wherein the bromine element contained in the (meth)acrylic polymer (A) is 0 ppm or more and 15 ppm or less. The curable composition according to any one of claims 1 to 3, wherein the epoxy compound and/or oxetane compound (B) is an aromatic epoxy compound. The curable composition according to any one of claims 1 to 4, wherein the epoxy compound and/or oxetane compound (B) is an epoxy compound having a radical reactive group. The curable composition according to any one of claims 1 to 5, wherein the epoxy curing agent (D) is an amine compound. A method for producing the curable composition according to any one of claims 1 to 6,
A step of producing the (meth)acrylic polymer (A) using a copper complex, a polydentate amine, a base other than the polydentate amine, and a reducing agent;
The obtained (meth)acrylic polymer (A), the epoxy compound and/or oxetane compound (B), the photoradical polymerization initiator (C), and the epoxy curing agent (D) are mixed. and
A method for producing a curable composition, comprising: