Curable composition, cured product, and electronic component

Abstract

[Problem] To provide: a curable composition that includes an AMA ester and produces cured products that are flexible, have low warpage, and adhere to conductor circuits; a cured product of the curable composition; and an electronic component that includes the cured product. [Solution] A curable composition that contains (A) a polymerizable monomer that is represented by formula (1) (in which R1 is a straight-chain, branched, or cyclic C1–4 hydrocarbon group that may include an ether linkage (and may also include a substituent)), (B) a compound selected from the group that consists of melamine and derivatives thereof, (C) a photopolymerization initiator, and (D) a thermosetting component. Cured products of the curable composition are flexible, have low warpage, and have high adhesion to conductor circuits.

Description

[Technical Field]

[0001] The present invention relates to a curable composition, a cured product thereof, and an electronic component comprising the cured product, and more particularly to a curable composition suitable for use as an insulating material for printed wiring boards, a cured product thereof, and an electronic component comprising the cured product. [Background technology]

[0002] Esters containing an α-allyloxymethylacryloyl group (hereinafter also referred to as AMA esters) undergo polymerization while cyclizing, forming a main chain skeleton having a five-membered ring ether structure with methylene groups on both sides as a repeating unit. Therefore, cured products containing this polymer have excellent properties such as thermal decomposition resistance, adhesion to resin substrates, and tough mechanical properties.

[0003] Patent Document 1 discloses a curable composition containing this AMA ester. Specifically, Patent Document 1 discloses a curable composition containing a specific AMA ester, a bifunctional or higher functional photopolymerizable monomer, and a radical polymerization agent. This curable composition has excellent curability and is useful as an insulating material for inkjet printed wiring boards. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-040585 Summary of the Invention [Problem to be solved by the invention]

[0005] As insulating materials for printed wiring boards, curable compositions that are applied onto circuit boards are known, and such curable compositions are adjusted to various viscosities depending on the application method. However, although a curable composition for use in printed wiring boards is required to have strong adhesion to conductor circuits, low warpage, and flexibility, Patent Document 1 does not disclose any of these properties.

[0006] The present inventors have found that the cured product described in Patent Document 1 does not sufficiently possess the properties of adhesion to conductor circuits, low warpage, and flexibility required for use as an insulating material for printed wiring boards.

[0007] In view of the above-mentioned problems, an object of the present invention is to provide a curable composition containing an AMA ester, which provides a cured product that has excellent adhesion to a conductor circuit, low warpage, and flexibility, a cured product thereof, and an electronic component that includes the cured product. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to achieve the above object, and as a result have found that by blending a compound selected from the group consisting of melamine and its derivatives and a thermosetting component in a curable composition in addition to an α-allyloxymethyl acrylic acid ester compound and a photopolymerization initiator, the resulting cured product can be made to have high adhesion to conductor circuits, low warpage, and flexibility, which led to the completion of the present invention.

[0009] That is, the object of the present invention is to (A) Formula (1) [ka] (In formula (1), R 1 represents a hydrocarbon group having 1 to 4 carbon atoms, which may be linear, branched, or cyclic, and which may contain an ether bond (however, the hydrocarbon group may have a substituent). and a polymerizable monomer represented by the formula: (B) a compound selected from the group consisting of melamine and its derivatives; (C) a photopolymerization initiator; (D) a thermosetting component; It has been found that this can be achieved by a curable composition comprising: Here, the curable composition of the present invention preferably has a viscosity at 50°C of 50 mPa·s or less.

[0010] Furthermore, it is preferable that the curable composition of the present invention contains (E) a compound having two or more (meth)acryloyl groups, and it is more preferable that the (E) compound having two or more (meth)acryloyl groups contains (E1) a compound having an aromatic ring and two or more (meth)acryloyl groups.

[0011] Furthermore, it is preferable that the (D) thermosetting component contains a latent thermosetting component, and it is more preferable that the latent thermosetting component is a blocked isocyanate compound.

[0012] Moreover, it is preferred that the curable composition of the present invention further comprises (F) a phosphorus-based flame retardant.

[0013] Preferably, the curable composition of the present invention further contains (G) an ion scavenger.

[0014] Furthermore, the above-mentioned object of the present invention can also be achieved by a cured product obtained from the curable composition of the present invention, and an electronic part having the cured product. [Effects of the Invention]

[0015] According to the curable composition of the present invention, the obtained cured product has high adhesion to conductor circuits, low warpage, and flexibility. Similarly, the cured product obtained from the curable resin composition of the present invention and the electronic component having this cured product each have high adhesion to conductor circuits, low warpage, and flexibility. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is an explanatory diagram of an MIT test performed on a cured film obtained from a curable composition. DETAILED DESCRIPTION OF THE INVENTION

[0017] <Curable composition> The curable composition of the present invention comprises: (A) Formula (1) [ka] (In formula (1), R 1 represents a hydrocarbon group having 1 to 4 carbon atoms, which may be linear, branched, or cyclic, and which may contain an ether bond (however, the hydrocarbon group may have a substituent). (hereinafter also referred to as polymerizable monomer of formula (1) (A)) (B) a compound selected from the group consisting of melamine and its derivatives; (C) a photopolymerization initiator; (D) a thermosetting component; It has.

[0018] [(A) Polymerizable Monomer of Formula (1)] The polymerizable monomer of formula (A) (1) contained in the curable composition of the present invention can suppress warping of the cured product after exposure, particularly on flexible printed wiring boards having flexibility. If the cured product warps excessively, the entire flexible printed wiring board becomes cylindrical, which can cause the problem of making it impossible to apply the curable composition to the appropriate position when recoating. Furthermore, in the case of inkjet printing applications, warping of the flexible printed wiring board can cause the board to come into contact with the inkjet head. Furthermore, there is also the problem of further increasing warping during thermal curing. However, since the curable composition of the present invention contains the polymerizable monomer of formula (A) (1), warping of the cured product after exposure and warping after thermal curing can be suppressed. The polymerizable monomer (A) of formula (1) contained in the curable composition of the present invention is, for example, a polymerizable monomer represented by the following formula a): TIFF0007766584000003.tif14551 (formula a), R 1 is R in equation (1). 1 where X represents an initiating or propagating radical), the polymerization reaction proceeds with cyclization, so it is thought to form a main chain skeleton with repeating units of a five-membered ring ether structure with methylene groups on both sides.

[0019] Examples of the hydrocarbon group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a vinyl group, an allyl group, a methallyl group, a crotyl group, a cyclopropyl group, a cyclobutyl group, a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an ethoxyethyl group, and a vinyloxyethyl group.

[0020] Examples of the substituent include chain unsaturated hydrocarbon groups such as vinyl, allyl, methallyl, and crotyl groups; alkoxy groups such as methoxy, ethoxy, and methoxyethoxy groups; alkylthio groups such as methylthio and ethylthio groups; acyl groups such as acetyl and propionyl groups; acyloxy groups such as acetyloxy and propionyloxy groups; alkoxycarbonyl groups such as methoxycarbonyl and ethoxycarbonyl groups; alkylthiocarbonyl groups such as methylthiocarbonyl and ethylthiocarbonyl groups; halogen atoms such as fluorine, chlorine, bromine, and iodine atoms; ureido groups; amido groups; cyano groups; and trimethylsilyl groups.

[0021] R 1 From the viewpoints of industrial ease of producing the polymerizable monomer of formula (1) (A) and of reducing the viscosity of the polymerizable monomer of formula (1) (A) and of reducing the viscosity of the curable composition, preferred are linear saturated hydrocarbon groups having from 1 to 4 carbon atoms, linear unsaturated hydrocarbon groups having from 1 to 4 carbon atoms, and hydrocarbon groups having an ether bond having from 1 to 4 carbon atoms, and more preferred are methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, allyl, methallyl, crotyl, methoxyethyl, ethoxyethyl, and vinyloxyethyl groups.

[0022] Examples of the polymerizable monomer of formula (1) (A) include methyl α-allyloxymethylacrylate, ethyl α-allyloxymethylacrylate, n-propyl α-allyloxymethylacrylate, isopropyl α-allyloxymethylacrylate, n-butyl α-allyloxymethylacrylate, sec-butyl α-allyloxymethylacrylate, tert-butyl α-allyloxymethylacrylate, vinyl α-allyloxymethylacrylate, allyl α-allyloxymethylacrylate, methallyl α-allyloxymethylacrylate, crotyl α-allyloxymethylacrylate, methoxymethyl α-allyloxymethylacrylate, methoxyethyl α-allyloxymethylacrylate, methoxypropyl α-allyloxymethylacrylate, methoxybutyl α-allyloxymethylacrylate, ethoxymethyl α-allyloxymethylacrylate, ethoxyethyl α-allyloxymethylacrylate, vinyloxyethyl α-allyloxymethylacrylate, etc. These may be used alone or in combination of two or more.

[0023] The polymerizable monomer of formula (A) (1) can be prepared, for example, according to the methods described in JP-A Nos. 2014-040585 and 2011-137123.

[0024] The blending amount of the polymerizable monomer of formula (A) (1) is preferably 1 part by mass or more and 80 parts by mass or less, more preferably 5 parts by mass or more and 60 parts by mass or less, and particularly preferably 5 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the curable composition of the present invention.

[0025] [(B) A compound selected from the group consisting of melamine and its derivatives] The curable composition of the present invention contains (B) a compound selected from the group consisting of melamine and its derivatives. Melamine and its derivatives are used to improve the adhesion of the cured product to the conductor circuit and further improve properties such as heat resistance.

[0026] (B) Examples of the compound selected from the group consisting of melamine and its derivatives include guanamines such as acetoguanamine and benzoguanamine; melamine; and triazine derivatives such as ethyldiamino-S-triazine, 2,4-diamino-S-triazine, and 2,4-diamino-6-xylyl-S-triazine, among which melamine is preferred.

[0027] The compound (B) selected from the group consisting of melamine and its derivatives can be used alone or in combination of two or more. When the compound (B) selected from the group consisting of melamine and its derivatives is blended in the curable composition of the present invention, the blending amount thereof is preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 20% by mass or less, and particularly preferably 1% by mass or more and 15% by mass or less, where the total amount of the thermosetting component (D) described below is taken as 100% by mass.

[0028] By setting the blending amount of (B) the compound selected from the group consisting of melamine and its derivatives to 0.1 mass % or more and 20 mass % or less, relative to 100 mass % of the total amount of (D) the thermosetting component, it is possible to improve the storage stability of the curable composition and achieve good thermosetting.

[0029] [(C) Photopolymerization initiator] As the (C) photopolymerization initiator, any compound that generates radicals by light, laser, electron beam, etc. and initiates a radical polymerization reaction can be used. Examples of the (C) photopolymerization initiator include benzoin and benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, and 1,1-dichloroacetophenone; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1; -one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, N,N-dimethylaminoacetophenone and other aminoacetophenones; anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone and other anthraquinones; thioxanthone such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone and other thioxanthones Xanthones; ketals such as acetophenone dimethyl ketal and benzil dimethyl ketal; 2,4,5-triarylimidazole dimer; riboflavin tetrabutylate; thiol compounds such as 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, and 2-mercaptobenzothiazole; organic halogen compounds such as 2,4,6-tris-s-triazine, 2,2,2-tribromoethanol, and tribromomethylphenyl sulfone; benzophenone benzophenones or xanthones such as 4,4'-bisdiethylaminobenzophenone; acylphosphines such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide; and oxime esters such as 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime).

[0030] The photopolymerization initiator (C) can be used alone or in combination of two or more. In addition to these, photoinitiator assistants such as N,N-dimethylaminobenzoic acid ethyl ester, N,N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, triethanolamine, and other tertiary amines can also be used. Titanocene compounds such as Omnirad 784 (manufactured by IGM Resins BV), which absorb light in the visible light region, can also be added to the photopolymerization initiator (C) to promote photoreaction. The components added to the photopolymerization initiator are not limited to these. Any component that absorbs light in the ultraviolet or visible light region and radically polymerizes ethylenically unsaturated groups such as (meth)acryloyl groups can be used alone or in combination, regardless of whether it is a photopolymerization initiator or a photoinitiator assistant.

[0031] Examples of commercially available (C) photopolymerization initiators include Omnirad 907, Omnirad 127, and Omnirad 379EG (all manufactured by IGM Resins BV).

[0032] The photopolymerization initiator (C) may be a compound that initiates a cationic polymerization reaction. Examples of such photopolymerization initiators (C) include diphenyliodonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, 2,4,6-triphenylthiopyrylium hexafluorophosphate, and commercially available sulfonium salt-based cationic photopolymerization initiators such as Optoma-SP-170 and SP-152 manufactured by ADEKA Corporation, and CPI-100P, CPI-101A, CPI-200K, and CPI-210S manufactured by San-Apro Co., Ltd., and Irgacure (registered trademark) 261 manufactured by BASF.

[0033] The amount of the (C) photopolymerization initiator to be added is preferably 0.2 to 25 parts by mass, more preferably 0.5 to 20 parts by mass, based on 100 parts by mass of the curable composition of the present invention.

[0034] [(D) Thermosetting component] The curable composition of the present invention also contains a thermosetting component (D), which is different from the polymerizable monomer (A) of formula (1). The inclusion of the thermosetting component (D) not only improves the adhesion of the cured film to the conductor circuit, but also further improves functionality such as heat resistance, plating resistance, flexibility, solvent resistance, and flame retardancy.

[0035] As the (D) thermosetting component, for example, known compounds such as blocked isocyanate compounds, epoxy compounds, and oxetane compounds can be used.

[0036] Among these, in the present invention, a latent thermosetting component in which functional groups in the structure are protected by a protecting group can be particularly preferably used. The use of such a latent thermosetting component can suppress unintended reactions in the curable composition due to unexpected conditions, thereby improving the storage stability of the curable composition. Furthermore, such a curable composition has excellent inkjet printability at 50°C, and can be easily deprotected by heating or the like during curing, thereby activating the latent thermosetting component. In the present invention, "latent" refers to a property in which the component is not active at room temperature or under slightly elevated temperatures, but is activated and exhibits thermosetting properties when heated at a high temperature of 80°C or higher.

[0037] Such a latent thermosetting component is preferably a blocked isocyanate compound. The blocked isocyanate compound is a compound having preferably a plurality of blocked isocyanate groups in one molecule. A blocked isocyanate group is an isocyanate group that is protected and temporarily inactivated by reaction with a blocking agent, and when heated to a predetermined temperature, the blocking agent dissociates to generate an isocyanate group.

[0038] As the polyisocyanate compound having a plurality of isocyanate groups, for example, an aromatic polyisocyanate, an aliphatic polyisocyanate, or an alicyclic polyisocyanate can be used.

[0039] Specific examples of aromatic polyisocyanates include 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, o-xylylene diisocyanate, m-xylylene diisocyanate, and 2,4-tolylene dimer.

[0040] Specific examples of aliphatic polyisocyanates include tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4-methylenebis(cyclohexyl isocyanate), and isophorone diisocyanate.

[0041] Specific examples of alicyclic polyisocyanates include bicycloheptane triisocyanate, as well as adducts, biuret compounds, and isocyanurates of the isocyanate compounds listed above.

[0042] Examples of isocyanate blocking agents include phenol-based blocking agents such as phenol, cresol, xylenol, chlorophenol, and ethylphenol; lactam-based blocking agents such as ε-caprolactam, δ-valerolactam, γ-butyrolactam, and β-propiolactam; active methylene-based blocking agents such as ethyl acetoacetate and acetylacetone; and alkoxyl-based blocking agents such as methanol, ethanol, propanol, butanol, amyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether, benzyl ether, methyl glycolate, butyl glycolate, diacetone alcohol, methyl lactate, and ethyl lactate. Examples of suitable blocking agents include alcohol-based blocking agents; oxime-based blocking agents such as formaldehyde oxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, diacetyl monooxime, and cyclohexane oxime; mercaptan-based blocking agents such as butyl mercaptan, hexyl mercaptan, t-butyl mercaptan, thiophenol, methylthiophenol, and ethylthiophenol; acid amide-based blocking agents such as acetic acid amide and benzamide; imide-based blocking agents such as succinimide and maleimide; amine-based blocking agents such as xylidine, aniline, butylamine, and dibutylamine; imidazole-based blocking agents such as imidazole and 2-ethylimidazole; imine-based blocking agents such as methyleneimine and propyleneimine; and pyrazole-based blocking agents such as dimethylpyrazole.

[0043] The blocked isocyanate compound may be a commercially available product, and examples thereof include Duranate TPA-B80E, 17B-60PX, and E402-B80T (all manufactured by Asahi Kasei Corporation), and Trixene BI7982: blocked isocyanate (hexamethylene isocyanate (HDM) trimer, blocking agent: dimethylpyrazole (DMP), manufactured by Baxenden Chemicals).

[0044] The latent thermosetting component may be a reaction product obtained by reacting an amine compound such as imidazole or dicyandiamide with a hydroxyl group-containing compound, a cyclic ether group-containing compound, a carboxyl group-containing compound, or the like.

[0045] The blending amount of the (D) thermosetting component is preferably from 1 to 30 parts by mass, more preferably from 5 to 25 parts by mass, per 100 parts by mass of the curable composition of the present invention. By blending the (D) thermosetting component in an amount of from 1 to 30 parts by mass per 100 parts by mass of the curable composition of the present invention, the storage stability of the curable composition of the present invention can be maintained while further improving the functionality of the cured film, such as heat resistance and plating resistance.

[0046] [(E) Compounds having two or more (meth)acryloyl groups] The curable composition of the present invention preferably contains (E) a compound having two or more (meth)acryloyl groups. (E) The compound having two or more (meth)acryloyl groups is a component that is blended to be cured by a photopolymerization reaction to form a cured product. (E) The compound having two or more (meth)acryloyl groups is different from (A) the polymerizable monomer of formula (1).

[0047] Having two or more (meth)acryloyl groups makes it possible to obtain good curability by photopolymerization reaction. Here, the term "(meth)acryloyl group" is a general term that refers to an acryloyl group and a methacryloyl group.

[0048] Furthermore, in order to impart functionality as a solder resist, such as good adhesion to conductor circuits and film hardness to the cured film (cured product) even after heat history, i.e., after soldering, it is more preferable that the (E) compound having two or more (meth)acryloyl groups includes (E1) a compound having an aromatic ring and two or more (meth)acryloyl groups.

[0049] (E1) Examples of the compound having an aromatic ring and two or more (meth)acryloyl groups include (meth)acrylates of polyhydric phenols and their alkylene oxide adducts.

[0050] Examples of polyhydric phenols include bisphenols such as bisphenol A, bisphenol AP, bisphenol B, bisphenol BP, bisphenol E, bisphenol F, bisphenol M, bisphenol P, bisphenol PH, and bisphenol Z, and biphenols.

[0051] Examples of alkylene oxides include ethylene oxide, propylene oxide, and butylene oxide. The number of alkylene oxides added is preferably 6 or less.

[0052] (E1) Examples of commercially available compounds having an aromatic ring and two or more (meth)acryloyl groups include ABE-300 (manufactured by Shin-Nakamura Chemical Co., Ltd.), BPE-80N (manufactured by Shin-Nakamura Chemical Co., Ltd.), BPE-100 (manufactured by Shin-Nakamura Chemical Co., Ltd.), A-BPE-4 (manufactured by Shin-Nakamura Chemical Co., Ltd.), BPE-4 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), BPE-10 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), BPE-200 (manufactured by Shin-Nakamura Chemical Co., Ltd.), and EBECRYL 150 (manufactured by Daicel-Allnex Corporation).

[0053] Furthermore, from the viewpoint of obtaining good curability while reducing the viscosity of the curable composition, the (E) compound having two or more (meth)acryloyl groups preferably includes a low-viscosity compound having two (meth)acryloyl groups. Here, in the (E) compound having two or more (meth)acryloyl groups, low viscosity means a viscosity at 50°C of 50 mPa s or less, particularly a viscosity at 50°C of 20 mPa s or less.

[0054] Examples of low-viscosity compounds having two (meth)acryloyl groups include bifunctional (meth)acryloyl group-containing monomers, which are esters of alkylene glycol and (meth)acrylic acid.

[0055] The alkylene glycol may be a monoalkylene glycol or may have a repeating structure of two or more alkylene glycols. Examples of the monoalkylene glycol include linear or branched alkylene diols having 3 to 16 carbon atoms, preferably 6 to 9 carbon atoms.

[0056] Examples of the alkylene glycol having a repeating structure of two or more alkylene glycols include diethylene glycol, dipropylene glycol, dibutylene glycol, triethylene glycol, tripropylene glycol, and tributylene glycol.

[0057] Specific examples of low-viscosity compounds having two (meth)acryloyl groups include diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, dibutylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tributylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol acrylate, 1,10-decanediol diacrylate, and 1,16-hexadecanediol diacrylate.

[0058] Commercially available low-viscosity compounds having two (meth)acryloyl groups include 2G (manufactured by Shin-Nakamura Chemical Co., Ltd.), 3G (manufactured by Shin-Nakamura Chemical Co., Ltd.), DPGDA (manufactured by Daicel-Allnex Co., Ltd.), T0948 (manufactured by Tokyo Chemical Industry Co., Ltd.), T2389 (manufactured by Tokyo Chemical Industry Co., Ltd.), Viscoat #310HP (manufactured by Osaka Organic Chemical Industry Co., Ltd.), PE-200 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), PE-300 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), HDDA (manufactured by Daicel-Allnex Co., Ltd.), L-C9A (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), A-NOD-N (manufactured by Shin-Nakamura Chemical Co., Ltd.), B1065 (manufactured by Tokyo Chemical Industry Co., Ltd.), and 1,9-NDA (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.).

[0059] In order to further improve the curability by the photopolymerization reaction, it is preferable that the (E) compound having two or more (meth)acryloyl groups contains a compound having three or more (meth)acryloyl groups.

[0060] Examples of the compound having three or more (meth)acryloyl groups include trimethylolpropane triacrylate, trimethylolmethane triacrylate, ethylene oxide-modified trimethylolpropane triacrylate, propylene oxide-modified trimethylolpropane triacrylate, epichlorohydrin-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, tetramethylolmethane tetraacrylate, ethylene oxide-modified phosphate triacrylate, propylene oxide-modified phosphate triacrylate, epichlorohydrin-modified glycerol triacrylate, dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, and polyfunctional acrylates typified by silsesquioxane-modified products thereof, as well as corresponding methacrylate monomers and ε-caprolactone-modified trisacryloxyethyl isocyanurate.

[0061] The compound having three or more (meth)acryloyl groups may be a multi-branched oligomer or polymer.

[0062] The amount of the (E) compound having two or more (meth)acryloyl groups is preferably 10 parts by mass or more and 90 parts by mass or less, more preferably 10 parts by mass or more and 80 parts by mass or less, and particularly preferably 15 parts by mass or more and 75 parts by mass or less, per 100 parts by mass of the curable composition of the present invention.

[0063] When the amount of the (E) compound having two or more (meth)acryloyl groups is 10 parts by mass or more per 100 parts by mass of the curable composition of the present invention, compatibility is improved, uniform dispersion occurs, and good coating film properties are obtained, while when the amount is 90 parts by mass or less, the effect of improving heat resistance is obtained.

[0064] [(F) Phosphorus-based flame retardants] The curable composition of the present invention preferably contains a known and commonly used phosphorus-based flame retardant (F) for the purpose of improving the flame retardancy of the resulting cured product.

[0065] (F) Examples of the phosphorus-based flame retardant include phosphate esters and condensed phosphate esters, phosphorus-containing compounds having a phenolic hydroxyl group, phosphazene compounds, metal phosphinates, and compounds represented by the following general formula (2): [ka] (In formula (2), R 2 , R 3 and R 4 each independently represents a substituent other than a halogen atom.

[0066] In the above general formula (2), R 2 , R 3 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R 4 is preferably, but not limited to, a hydrogen atom, an alkyl group having 1 to 4 carbon atoms which may be substituted with a cyano group, a 2,5-dihydroxyphenyl group, or a 3,5-di-t-butyl-4-hydroxyphenyl group.

[0067] Commercially available products of the compound represented by the general formula (2) include HCA, SANKO-220, M-ESTER, and HCA-HQ (all trade names of Sankosha).

[0068] The phosphorus-containing compound having a phenolic hydroxyl group includes the compound represented by the general formula (2) above, R 4 However, examples include those in which the phenyl group is substituted with a hydroxyl group. Commercially available products include HCA-HQ manufactured by Sankosha.

[0069] Examples of the metal phosphinate include those represented by the following structural formula (3): [ka] (In formula (3), R1 and R2 each represent an alkyl group having 1 to 6 carbon atoms or an aryl group having 12 or less carbon atoms; M represents calcium, aluminum, or zinc, and when M represents aluminum, m=3, and when M represents any other metal, m=2. Preferably, the compound has a structure represented by the following formula:

[0070] More preferred is a compound having a structure in which M in formula (3) represents aluminum.

[0071] By using a metal phosphinate, the flame retardancy of the cured film can be improved without impairing the flexibility of the film.

[0072] Specific examples of the phosphinic acid constituting the metal phosphinate include phosphinic acid, dimethylphosphinic acid, ethylmethylphosphinic acid, diethylphosphinic acid, methyl-n-propylphosphinic acid, methanedi(methylphosphinic acid), benzene-1,4-(dimethylphosphinic acid), methylphenylphosphinic acid, phenylphosphinic acid, diphenylphosphinic acid, and mixtures thereof.

[0073] Commercially available products include, for example, Exolit OP 1240, 1240, 1312, 1400, 930, 945TP, and OP-935.

[0074] The phosphazene compound is preferably a compound having a phosphazene structure and a phenoxy group substituted with one of a cyano group (-CN), a hydroxyl group (-OH), and a methyl group. In particular, it is preferable that the phosphazene compound has a hexaphenoxycyclotriphosphazene structure as a basic skeleton, and at least two of the six phenoxy groups in the structure are substituted with a cyano group (-CN) or a hydroxyl group (-OH).

[0075] A preferred embodiment is a structure in which only one of the two phenoxy groups bonded to the phosphorus atom in the hexaphenoxycyclotriphosphazene structure is substituted with one cyano group (-CN), and the hexaphenoxycyclotriphosphazene structure as a whole has two such substituted phenoxy groups.

[0076] Another preferred embodiment is a structure in which each of the two phenoxy groups bonded to the phosphorus atom in the hexaphenoxycyclotriphosphazene structure is substituted with a cyano group (-CN), and the entire hexaphenoxycyclotriphosphazene structure has six phenoxy groups substituted in this way.

[0077] Another preferred embodiment is a structure in which only one of the two phenoxy groups bonded to the phosphorus atom in the hexaphenoxycyclotriphosphazene structure is substituted with one hydroxyl group (—OH), and the hexaphenoxycyclotriphosphazene structure as a whole has three such substituted phenoxy groups.

[0078] More preferably, the cyclic phosphazene compound has the following structure: [ka] or [ka] or [ka] The structure has one of the following structures:

[0079] Preferred commercially available phosphazene compounds include, for example, FP-300B, FP-300, and SPH-100 (all manufactured by Fushimi Pharmaceutical Co., Ltd.).

[0080] The (F) phosphorus-based flame retardant may be used alone or in combination of two or more. When the (F) phosphorus-based flame retardant is used, the amount thereof is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, per 100 parts by mass of the curable composition of the present invention. In particular, the amount of the (F) phosphorus-based flame retardant is preferably 0.1 to 10%, more preferably 1 to 5%, in terms of the phosphorus content in the curable composition of the present invention. When the (F) phosphorus-based flame retardant is used within the above range, flame retardancy can be effectively imparted while maintaining heat resistance and low warpage. In addition, in the curable composition of the present invention, a metal borate (zinc borate compound (2ZnO·3B2O3·3.5H2O) such as Firebrake ZB may be used as a flame retardant.

[0081] [(G) Ion scavenger] The curable composition of the present invention preferably contains a known and commonly used ion scavenger (G) in order to improve insulation reliability such as ion migration resistance.

[0082] Examples of the (G) ion scavenger include inorganic cation scavenger agents that capture cations by ion exchange, inorganic anion scavenger agents that capture anions by ion exchange, and inorganic amphoteric ion scavenger agents that capture both cations and anions by ion exchange, with inorganic amphoteric ion scavenger agents being preferred.

[0083] The (G) ion scavenger contains at least one component selected from the group consisting of zirconium, aluminum, zinc, magnesium, and bismuth. Oxide hydrates or hydroxides of two or more of these components are particularly preferred, with two or more oxide hydrates or hydroxides selected from the group consisting of zirconium, magnesium, and aluminum being more preferred. Among these, ternary oxide hydrates of magnesium, aluminum, and zirconium, binary oxide hydrates of bismuth and zirconium, and hydrotalcite, a hydroxide containing magnesium and aluminum, are preferred. The ion scavenger may be used alone or in combination of two or more.

[0084] Hydrotalcite is represented by the following formula (1).

[0085] Mg a Al b (OH) c (CO3) d nH2O (1) (In formula (1), a, b, c, and d are positive numbers and satisfy the relationship 2a+3b-c-2d=0. Furthermore, n represents the number of hydrations and is 0 or a positive number, preferably 1 to 5.)

[0086] In formula (1), a part of Mg may be replaced with another divalent metal ion, and among the other divalent metal ions, Zn is particularly preferred.

[0087] Specific examples of hydrotalcite include, but are not limited to, Mg 4.5 Al2(OH) 13 CO3·nH2O, Mg5Al 1.5 (OH) 12.5 CO3·nH2O, Mg6Al2(OH) 16 CO3·nH2O, Mg 4.2 Al2(OH) 12.4 CO3·nH2O, Mg 4.3 Al2(OH) 12.6 CO3·nH2O, Mg 2.5 Zn2Al2(OH) 13 CO3·nH2O, Mg 4.2 Al2(OH) 12.4 CO3·nH2O, Mg 4.2 Al2(OH) 12.4 CO3·nH2O, Mg4Al2(OH) 12 CO3·nH2O, etc. (where n represents the number of hydrations, and is 0 or a positive number, preferably 1 to 5). Among these, Mg 4.3 Al2(OH) 12.6 CO3·nH2O is preferred.

[0088] In the hydrotalcite represented by formula (1), a / b is preferably 1.5 or more and 5 or less, more preferably 1.7 or more and 3 or less, and even more preferably 1.8 or more and 2.5 or less.

[0089] The average particle size of the ion scavenger (G) is usually 5 μm or less, preferably 1 μm or less. The lower limit of the average particle size is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.1 μm or more, and even more preferably 0.3 μm or more.

[0090] The average particle size of the ion scavenger can be measured by dynamic light scattering. Specifically, a particle size distribution of the ion scavenger is created on a volume basis using a dynamic light scattering particle size distribution analyzer, and the median diameter (D50) is used as the average particle size. A preferred measurement sample is one in which the ion scavenger is dispersed in water using ultrasonic waves. A Nanotrac Wave II UT151 manufactured by Microtrack Bell Corporation or the like can be used as a dynamic light scattering particle size distribution analyzer.

[0091] (G) The ion scavenger may be a commercially available product, and examples thereof include IXEPLAS-A1, IXEPLAS-A2, IXEPLAS-A3, and IXEPLAS-B1 manufactured by Toagosei Co., Ltd., and DHT-4A, DHT-4A-2, and DHT-4C manufactured by Kyowa Chemical Industry Co., Ltd.

[0092] When (G) an ion scavenger is added, the amount thereof is preferably 0.01 to 10 parts by mass, more preferably 0.02 to 5 parts by mass, and even more preferably 0.03 to 3 parts by mass, relative to 100 parts by mass of the curable composition of the present invention. When the amount of the ion scavenger is within the above range, the insulation reliability and adhesion after high-temperature and high-humidity conditions can be improved without reducing flexibility, low warpage, and flame retardancy.

[0093] [Compounds having a (meth)acryloyl group and a hydroxyl group (excluding (E) compounds having two or more (meth)acryloyl groups)] Furthermore, the curable composition of the present invention preferably contains a compound having a (meth)acryloyl group and a hydroxyl group, which improves the adhesion of the obtained cured film to the conductor and the substrate.

[0094] Examples of compounds having a (meth)acryloyl group and a hydroxyl group include 2-hydroxy-3-acryloyloxypropyl (meth)acrylate, 2-hydroxy-3-phenoxyethyl (meth)acrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, 2-hydroxypropyl (meth)acrylate, etc. Commercially available products include Aronix M-5700 (trade name, manufactured by Toagosei Co., Ltd.), 4HBA, 2HEA, CHDMMA (all trade names, manufactured by Kyoeisha Chemical Co., Ltd.), BHEA, HPA, HEMA, HPMA (all trade names, manufactured by Nippon Shokubai Co., Ltd.), Light Ester HO, Light Ester HOP, Light Ester HOA (all trade names, manufactured by Kyoeisha Chemical Co., Ltd.), etc. The compound having a (meth)acryloyl group and a hydroxyl group can be used alone or in combination of two or more kinds.

[0095] Among these, 2-hydroxy-3-acryloyloxypropyl acrylate, 2-hydroxy-3-phenoxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, and 1,4-cyclohexanedimethanol monoacrylate are particularly preferably used.Furthermore, from the viewpoint of ease of viscosity adjustment, compounds having one (meth)acryloyl group are preferably used.

[0096] The amount of the compound having a (meth)acryloyl group and a hydroxyl group added is preferably 1 to 15 parts by mass, more preferably 1 to 10 parts by mass, and particularly preferably 2 to 8 parts by mass, per 100 parts by mass of the curable composition of the present invention.

[0097] The curable composition of the present invention may contain additives such as antioxidants, antifoaming / leveling agents, thixotropy-imparting agents / thickeners, coupling agents, dispersants, polymerization retarders, and colorants, as needed.

[0098] Furthermore, the curable composition of the present invention may contain a solvent to adjust the viscosity, but the amount added is preferably small to prevent a decrease in film thickness after curing.Moreover, it is more preferable that the curable composition does not contain a solvent for adjusting the viscosity.

[0099] The curable composition of the present invention is preferably applied to printing by the inkjet method. In order to be applicable to printing by the inkjet method, it is preferable that the composition has a viscosity that allows it to be sprayed by an inkjet printer.

[0100] The viscosity of the curable composition of the present invention is preferably 50 mPa·s or less at 50° C., more preferably 20 mPa·s or less at 50° C., and particularly preferably 15 mPa·s or less at 50° C. The viscosity is measured in accordance with the viscosity measurement method using a 10 cone-plate rotational viscometer of JIS Z8803:2011, at 50° C., 100 rpm, and 30 seconds using a cone-plate viscometer (TVE-33H, manufactured by Toki Sangyo Co., Ltd.) with a 1°34' x R24 cone rotor.

[0101] Therefore, the curable composition of the present invention can be used to directly print a pattern on a substrate for a printed wiring board or the like by inkjet printing.

[0102] Furthermore, the curable composition of the present invention does not undergo a polymerization reaction at room temperature, and therefore can be stably stored as a one-component curable composition.

[0103] When the viscosity of the curable composition of the present invention is adjusted to 50 mPa·s or less at 50° C., it can be supplied as ink to an inkjet printer and used for printing on a substrate.

[0104] <Cured product obtained from curable composition> The cured product obtained from the curable composition of the present invention can be obtained by, for example, applying 50 mJ / cm 2 to the composition layer immediately after printing. 2 ~1000mJ / cm 2 The curable composition can be obtained by photocuring the composition layer by irradiating it with active energy rays such as ultraviolet rays, electron beams, and actinic rays, preferably ultraviolet rays.

[0105] UV irradiation in an inkjet printer can be performed by attaching a light source such as a high-pressure mercury lamp, metal halide lamp, or UV LED to the side of the print head and scanning by moving the print head or substrate. In this case, printing and UV irradiation can be performed almost simultaneously.

[0106] The photocured product is then thermally cured using known heating means, such as a heating furnace, such as a hot air furnace, an electric furnace, or an infrared induction heating furnace. The heating conditions are preferably 130°C to 170°C for 5 to 90 minutes.

[0107] The cured product obtained from the curable composition of the present invention has excellent flexibility and is therefore particularly suitable as a solder resist for flexible printed wiring boards.

[0108] Examples of substrates for flexible printed wiring boards include films made of glass polyimide, polyimide, polyethylene terephthalate, liquid crystal polymer, polycarbonate, and the like.

[0109] <Electronic component having a cured product of the curable composition> When a cured film made of a curable composition pattern-printed on a substrate is used as a solder resist, it is heated in a soldering process for mounting components. Soldering may be performed by any of manual soldering, flow soldering, reflow soldering, etc. For example, in the case of reflow soldering, the solder is preheated at 100°C to 140°C for 1 to 4 hours, and then heated at 240°C to 280°C for about 5 to 20 seconds, which is repeated multiple times (e.g., 2 to 4 times) to heat and melt the solder. After cooling, an electronic component is completed, with components mounted as necessary.

[0110] In the present invention, the term "electronic component" refers to a component used in an electronic circuit, and includes active components such as printed wiring boards, transistors, light-emitting diodes, and laser diodes, as well as passive components such as resistors, capacitors, inductors, and connectors. The cured product of the curable composition of the present invention serves as an insulating cured film for these components, thereby exerting the effects of the present invention.

[0111] The curable composition of the present invention is easily reduced in viscosity, has excellent applicability, and exhibits little warping after photocuring. Furthermore, it remains flexible after curing and exhibits excellent adhesion to substrates, flame retardancy, solder heat resistance, plating resistance, and solvent resistance, making it suitable for a variety of applications, with no particular limitations on the scope of application. For example, it can be used to prepare etching resists, solder resists, and marking inks for printed wiring boards using an inkjet method, and is particularly suitable as a solder resist for flexible printed wiring boards, which require high heat resistance and flexibility.

[0112] It can also be used as a material for UV molding products, photolithography, and 3D inkjet printing.

[0113] The present invention is not limited to the configurations and examples of the above-described embodiments, and various modifications are possible within the scope of the gist of the invention. [Example]

[0114] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following, unless otherwise specified, "parts" refers to parts by mass.

[0115] <1. Preparation of Curable Compositions of Examples 1 to 8 and Comparative Examples 1 to 3> The components were blended in the proportions (unit: parts by mass) shown in Table 1 below and stirred with a dissolver. Then, dispersion was carried out for 2 hours with zirconia beads using a bead mill to obtain curable compositions of the present invention (Examples 1 to 8) and comparative curable compositions (Comparative Examples 1 to 3). A conical K-8 bead mill (manufactured by Buhler) was used, and kneading was carried out under the following conditions: rotation speed 1200 rpm, discharge rate 20%, bead diameter 0.65 mm, and packing ratio 88%.

[0116] [Table 1]

[0117] *1: α-(allyloxymethyl)methyl acrylate (FX-AOMA: manufactured by Nippon Shokubai Co., Ltd.) *2: Trimethylolpropane triacrylate (A-TMPT: manufactured by Shin-Nakamura Chemical Co., Ltd.) *3: 1,9-nonanediol diacrylate (1,9-NDA: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) *4: Dipropylene glycol diacrylate (DPGDA: manufactured by Toyo Chemicals Co., Ltd.) *5: Ethoxylated bisphenol A diacrylate (A-BPE-10: manufactured by Shin-Nakamura Chemical Co., Ltd.) *6: 4-Hydroxybutyl acrylate (4HBA: manufactured by Kyoeisha Chemical Co., Ltd.) *7: Trifunctional blocked isocyanate (BI7982: manufactured by Baxenden Chemical) *8: Melamine (Nissan Chemical Co., Ltd.) *9: 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (Omnirad 379: manufactured by IGM Resins) *10: Phosphazene compound (phosphorus content 12.5%) (FP-300B: Fushimi Pharmaceutical Co., Ltd.) *11: Metal phosphinate (phosphorus content 23%) (OP935: Clariant Chemicals) *12: Phosphorus-containing compound with a phenolic hydroxyl group (phosphorus content 9.6%) (HCA-HQ: manufactured by Sankosha) *13: Ion scavenger containing Mg-based compounds, Al-based compounds, and Zr-based compounds (IXEPLAS-A1: manufactured by Toagosei Co., Ltd.) *14: Phthalocyanine blue pigment (Pigment Blue 15:3) *15: Anthraquinone yellow pigment (Pigment Yellow 147)

[0118] <2. Evaluation> The viscosity of each of the curable compositions obtained in <1. Preparation of Curable Compositions of Examples 1 to 8 and Comparative Examples 1 to 3> was evaluated as follows. Test samples were also prepared as described below, and evaluations were conducted on the coatability, post-exposure warpage, flexibility (MIT test), solder heat resistance, solvent resistance, electroless gold plating resistance, flame retardancy, and adhesion after high-temperature, high-humidity exposure. The results are shown in Table 2.

[0119] (1) Viscosity The viscosity of each of the curable compositions obtained in <1. Preparation of curable compositions of Examples 1 to 8 and Comparative Examples 1 to 3> above was measured at 50°C, 100 rpm, and 30 seconds using a cone-plate viscometer (TVE-33H, manufactured by Toki Sangyo Co., Ltd.) using a 1°34' x R24 cone rotor, and evaluated according to the following criteria.

[0120] ◎: 10mPa·s or less ○: More than 10mPa·s but less than 20mPa·s ×: More than 20mPa·s

[0121] (2) Conditions for forming the cured film Each of the curable compositions obtained in <1. Preparation of curable compositions of Examples 1 to 8 and Comparative Examples 1 to 3> above was applied using an inkjet printing device CPS6151 (manufactured by Microcraft). The array used was a KM1024iSHE (manufactured by Konica Minolta, Inc., coating droplet volume 6 pL, number of nozzles 1024, head temperature 50°C). Photocuring was performed using an SGHUV-UN-L042-B (manufactured by Microcraft, LED light source, wavelength 365 nm) as the light source, with an intensity of 300 mJ / cm. 2 Then, a hot air circulation drying oven DF610 (manufactured by Yamato Scientific Co., Ltd.) was used as the heating device, and the coating was fully cured at 150°C for 60 minutes.

[0122] (3) Spreadability Each of the curable compositions obtained in <1. Preparation of curable compositions of Examples 1 to 8 and Comparative Examples 1 to 3> above was applied to a copper surface of sulfuric acid-treated ESPANEX (registered trademark) M (Nippon Steel Chemical & Material Co., Ltd.) to a coating thickness of 20 μm using an inkjet printing device CPS6151 (Microcraft Co., Ltd.). The surface of the cured film was visually observed and evaluated according to the following criteria.

[0123] ○: The coating is even and the surface is smooth. △: The entire surface is coated, but streaks occur in the direction of the head movement. ×: Part of the cured film is missing

[0124] (4) Warpage after exposure Each of the curable compositions obtained in the above <1. Preparation of curable compositions of Examples 1 to 8 and Comparative Examples 1 to 3> was photocured using an inkjet printing device CPS6151 (manufactured by Microcraft Co., Ltd.) under a photocuring condition of 800 mJ / cm 2The solution was applied to one side of sulfuric acid-treated Kapton (registered trademark) 200H (manufactured by DuPont-Toray Co., Ltd.). The resulting laminate of cured film after exposure was cut into a 5 cm x 5 cm (length x width) sample (film thickness: 15 μm). Each sample was left standing on a horizontal workbench for 30 minutes with the cured film side facing up, and the height of each of the four edges of the sample raised from the workbench was measured with a ruler to determine the average height of the four edges. The same test was performed three times for each sample, and the average value of the three tests was calculated and evaluated according to the following criteria.

[0125] ◎: The average total height of the four edges is 5 mm or less ○: The average total height of the four edges is more than 5 mm and less than 10 mm ×: The average total height of the four edges is 10 mm or more

[0126] (5) Flexibility (MIT Test) Each curable composition obtained in the above <1. Preparation of curable compositions of Examples 1 to 8 and Comparative Examples 1 to 3> was applied to a 25 μm polyimide substrate with a circuit pattern formed on it and a 12 μm thick copper plate treated with sulfuric acid using a Microcraft CP56151. A 20 μm thick cured film was then formed according to the above "(2) Conditions for forming the cured film." The resulting cured film was subjected to the MIT test (R=0.38 mm) based on JIS P8115 to evaluate its flexibility.

[0127] Specifically, as shown in Figure 1, test piece 1 was mounted on the device, and with a load F (0.5 kgf) applied, test piece 1 was attached vertically to clamp 2, and bent at a bending angle α of 135 degrees and a bending speed of 175 cpm, and the number of times it was bent back and forth until it broke was measured. The test environment was 25°C, and the radius of curvature was R = 0.38 mm. The evaluation criteria were as follows:

[0128] ◎: 150 times or more ○: 100-149 times △: 50 to 99 times ×: 49 times or less

[0129] (6) Solder heat resistance Each of the curable compositions obtained in the above <1. Preparation of curable compositions of Examples 1 to 8 and Comparative Examples 1 to 3> was photocured using an inkjet printing device CPS6151 (manufactured by Microcraft Co., Ltd.) under photocuring conditions of 800 mJ / cm 2 The test substrate was coated with the above-mentioned solution onto a circuit pattern board with a copper thickness of 12 μm and polyimide thickness of 50 μm, which had been treated with sulfuric acid. A 20 μm thick cured film was then formed according to the above "(2) Conditions for forming the cured film." A rosin-based flux was applied to the obtained evaluation board, which was then immersed once or twice in a solder bath set to 260°C for 5 seconds. The flux was then washed off with denatured alcohol, and a cross-cut tape peel test was performed to evaluate swelling and peeling of the cured film. The evaluation criteria were as follows:

[0130] ⊚: After immersion for 5 seconds twice, no peeling of the cured film was observed even when a peel test was carried out using Cellotape (registered trademark). ◯: After immersion for 5 seconds once, no peeling of the cured film was observed even when a peel test was carried out using Cellotape (registered trademark). ×: After immersion for 5 seconds once, the cured film swelled and peeled off.

[0131] (7) Solvent resistance Each of the curable compositions obtained in the above <1. Preparation of curable compositions of Examples 1 to 8 and Comparative Examples 1 to 3> was photocured using an inkjet printing device CPS6151 (manufactured by Microcraft Co., Ltd.) under photocuring conditions of 800 mJ / cm 2 The solution was applied to the copper surface of sulfuric acid-treated ESPANEX (registered trademark) M (manufactured by Nippon Steel Chemical & Material Co., Ltd.) and heated in a hot air circulation drying oven at 150°C for 60 minutes to obtain a cured film with a thickness of 20 μm. The cured film was immersed in propylene glycol monomethyl acetate for 30 minutes and then the condition of the cured film was evaluated. The evaluation criteria are as follows:

[0132] ○: No change was observed △: Only slight changes ×: Significant changes

[0133] (8) Electroless gold plating resistance Each curable composition obtained in the above <1. Preparation of Curable Compositions of Examples 1 to 8 and Comparative Examples 1 to 3> was applied to a circuit pattern substrate with a copper thickness of 12 μm and a polyimide thickness of 50 μm, which had been treated with sulfuric acid, using an inkjet printing device CPS6151 (manufactured by Microcraft Co., Ltd.). Then, a cured film with a thickness of 20 μm was formed according to the above "(2) Conditions for Forming the Cured Film." The obtained evaluation substrate was gold-plated using a commercially available electroless nickel plating bath and electroless gold plating bath under conditions of 5 μm nickel and 0.03 μm gold, and the surface condition of the cured film was observed. The evaluation criteria are as follows:

[0134] ○: No change was observed ×: Significant whitening or cloudiness occurred

[0135] (9) Flame retardancy Each curable composition obtained in the above <1. Preparation of curable compositions of Examples 1 to 8 and Comparative Examples 1 to 3> was applied to both sides of an FR-4 (0.8 mm thick) substrate using an inkjet printer CPS6151 (manufactured by Microcraft Co., Ltd.). Then, a cured film was formed according to the above "(2) Conditions for forming the cured film" (the coating film thickness on each side was 20 μm). The obtained cured film was subjected to a thin material vertical combustion test in accordance with the UL94 standard. The evaluation criteria are as follows:

[0136] ◎: Passed V-0, and the burning time of each sample was less than 3 seconds ○: Passed V-0, and the burning time of each sample was more than 3 seconds and less than 7 seconds V-0: Passed V-0, and the burning time of each sample was between 7 and 10 seconds Not: V-0 failed

[0137] (10) Adhesion after high temperature and humidity Each curable composition obtained in the above <1. Preparation of Curable Compositions of Examples 1 to 8 and Comparative Examples 1 to 3> was applied to the copper surface of sulfuric acid-treated ESPANEX® M (manufactured by Nippon Steel Chemical & Material Co., Ltd.) using an inkjet printer CPS6151 (manufactured by Microcraft Co., Ltd.). Subsequently, a 20 μm-thick cured film was formed according to the above "(2) Conditions for Forming the Cured Film." The resulting cured film was then exposed to a temperature of 85°C and a humidity of 85% for 500 hours, and then left at room temperature for 24 hours. A cross-cut tape peel test was then performed using each test substrate, and the number of remaining grids per 100 was counted and evaluated according to the following criteria.

[0138] ◎:100 pieces ○: 80 or more and 99 or less ×: 79 or less

[0139] [Table 2]

[0140] As shown in Table 2, Examples 1 to 8 according to the present invention exhibited excellent adhesion between the cured film (cured product) and the conductor circuit, low warpage, and flexibility. Furthermore, flame retardancy could be improved by adding (E1) a compound having an aromatic ring and two or more (meth)acryloyl groups or by adding a phosphorus-based flame retardant (see Examples 1 to 8). Furthermore, the addition of an ion scavenger further improved adhesion between the cured film (cured product) and the conductor circuit (see Examples 6 and 7).

Claims

1. (A) Formula (1) 【Chemistry 1】 (In formula (1), R １ represents a hydrocarbon group having 1 to 4 carbon atoms, which may be linear, branched, or cyclic and may contain an ether bond (however, the hydrocarbon group may have a substituent). and a polymerizable monomer represented by the formula: (B) a compound selected from the group consisting of melamine and its derivatives; (C) a photopolymerization initiator; (D) a thermosetting component; and Contains A curable composition, wherein the (D) thermosetting component contains a latent thermosetting component.

2. 2. The curable composition according to claim 1, having a viscosity of 50 mPa·s or less at 50°C.

3. 3. The curable composition according to claim 1, further comprising (E) a compound having two or more (meth)acryloyl groups.

4. The curable composition according to claim 3, characterized in that the compound (E) having two or more (meth)acryloyl groups includes (E1) a compound having an aromatic ring and two or more (meth)acryloyl groups.

5. 5. The curable composition according to claim 1, wherein the latent thermosetting component is a blocked isocyanate compound.

6. The curable composition according to any one of claims 1 to 5, further comprising (F) a phosphorus-based flame retardant.

7. The curable composition according to any one of claims 1 to 6, further comprising (G) an ion scavenger.

8. A cured product obtained from the curable composition according to any one of claims 1 to 7.

9. An electronic component comprising the cured product according to claim 8.

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