Curable composition, dry film and cured product thereof

Abstract

[Question] Provide: A curable composition capable of forming a solder mask layer having both flux resistance and flex resistance. [Solution] A curable composition comprising: (A) an alkali-soluble resin having at least one of a bisphenol A structure, a bisphenol F structure, and a urethane structure; (B) a photopolymerization initiator; and (C) an epoxy resin having an isocyanurate structure; the epoxy resin having an isocyanurate structure (C) having a structure in which a nitrogen atom in the isocyanurate structure and an epoxy group are bonded via an alkylene chain having at least two carbon atoms.

Description

Technical Field

[0001] The present invention relates to a curable composition, particularly a curable composition capable of forming a cured product having both flux resistance and bendability. Background Art

[0002] Conventionally, a solder resist layer (SR) is formed on a printed circuit board to protect the circuits, and semiconductor chips and the like are soldered (mounted) on the printed circuit board with the solder resist layer formed thereon. Examples of compositions for forming such solder resist layers include solder resist inks for circuit boards described in Patent Document 1, which use a photosensitive resin composition containing a carboxyl group-containing photosensitive polymer as a base.

[0003] On the other hand, during soldering, flux is typically applied to the surface of the connected circuits. However, during the application process, the flux is exposed to the entire surface of the printed circuit board (PCB) with the solder mask layer formed on it. This flux is used to remove oxides and contaminants from the circuit connection surface, prevent oxidation during heating, and further reduce the surface tension of the molten solder, thereby improving the solder's wettability at the joint.

[0004] On the other hand, as so-called flexible printed circuit boards, which are used for applications where printed circuit boards are bent, are increasingly used, the solder resist layer formed on the printed circuit board is required to have flexibility that can withstand bending.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 11-65117 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] In other words, the solder resist layer needs to have flux resistance, that is, the following performance: even during the high-temperature soldering process after applying flux, it maintains close adhesion to the printed circuit board and does not peel off from the printed circuit board. In addition, the solder resist layer also needs to have flexibility so that it does not crack even if the printed circuit board is bent.

[0010] However, in this regard, the solder resist layer obtained from the conventional composition described in Patent Document 1 is easily degraded by the flux component and has insufficient flexibility, making it difficult to achieve both flux resistance and bendability.

[0011] Solutions for solving problems

[0012] Therefore, in view of the above aspects, the present inventors conducted in-depth research and found that a curable composition containing an alkali-soluble resin having a bisphenol A structure, etc., and an epoxy resin having a specific structure having both an isocyanurate structure and an alkylene structure can form a solder mask layer having both flux resistance and bendability, thereby completing the present invention.

[0013] That is, the present invention relates to a curable composition comprising:

[0014] (A) an alkali-soluble resin having at least one structure of a bisphenol A structure, a bisphenol F structure, and a urethane structure;

[0015] (B) a photopolymerization initiator; and

[0016] (C) an epoxy resin having an isocyanurate structure,

[0017] The epoxy resin (C) having an isocyanurate structure has a structure in which a nitrogen atom in the isocyanurate structure and an epoxy group are bonded via an alkylene chain having 2 or more carbon atoms.

[0018] Furthermore, a preferred embodiment of the present invention relates to a curable composition further comprising a powdery or crystalline epoxy resin, preferably an epoxy resin having a biphenyl structure.

[0019] Furthermore, a more preferred embodiment of the present invention relates to a curable composition further comprising an epoxy resin having a dicyclopentadiene structure.

[0020] Furthermore, a more preferred embodiment of the present invention relates to a curable composition wherein the mass ratio of the epoxy resin (C) having an isocyanurate structure to the powder or crystalline epoxy resin to the epoxy resin having a dicyclopentadiene structure is 1:2 to 6:1 to 3.

[0021] Furthermore, a more preferred embodiment of the present invention relates to a curable composition further comprising urethane beads and / or epoxidized polybutadiene.

[0022] Furthermore, a more preferred embodiment of the present invention relates to a curable composition further comprising a cellulose resin.

[0023] Other aspects of the present invention also relate to: a dry film having a resin layer obtained from the curable composition; a cured product obtained by curing the curable composition or the resin layer of the dry film; and an electronic component having the cured product.

[0024] Effects of the Invention

[0025] According to the present invention, there is provided a curable composition capable of forming a solder resist layer having excellent flux resistance and bending properties. DETAILED DESCRIPTION

[0026] Hereinafter, each component that can constitute the curable composition of the present invention will be described.

[0027] [(A) Alkali-soluble resin]

[0028] The alkali-soluble resin (A) used in the present invention has at least one of a bisphenol A structure, a bisphenol F structure, and a urethane structure. As described below, it can of course be used in combination with an alkali-soluble resin having a structure other than these.

[0029] (A) The alkali-soluble resin is a resin containing one or more functional groups selected from the group consisting of a phenolic hydroxyl group, a mercapto group, and a carboxyl group, and being soluble in an alkaline solution. Preferred examples include compounds having two or more phenolic hydroxyl groups, carboxyl-containing resins, compounds having a phenolic hydroxyl group and a carboxyl group, and compounds having two or more mercapto groups. Examples of the alkali-soluble resin include carboxyl-containing resins and phenolic hydroxyl-containing resins, with carboxyl-containing resins being preferred.

[0030] The carboxyl-containing resin can form alkali developability by containing a carboxyl group. In addition, from the viewpoint of light curing property and development resistance, in addition to the carboxyl group, it is preferred to have an ethylenically unsaturated group in the molecule, or it is also possible to use only a carboxyl-containing resin without an ethylenically unsaturated group. As the ethylenically unsaturated group, it is preferred to be derived from acrylic acid or methacrylic acid or their derivatives. Among the carboxyl-containing resins, preferred are: a carboxyl-containing resin having a carbamate structure, a carboxyl-containing resin using bisphenol A type epoxy resin or bisphenol F type epoxy resin as a starting material, and a carboxyl-containing resin using bisphenol A or bisphenol F as a starting material. As specific examples of the carboxyl-containing resin, the following compounds (either oligomers or polymers) can be cited.

[0031] (1) A carboxyl group-containing photosensitive resin obtained by reacting a bisphenol A epoxy resin or a bisphenol F epoxy resin with (meth)acrylic acid and adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the hydroxyl groups present in the side chains. The bifunctional or higher-functional epoxy resin is preferably a solid.

[0032] (2) A carboxyl group-containing photosensitive resin obtained by epoxidizing the hydroxyl groups of a bisphenol A epoxy resin or a bisphenol F epoxy resin with epichlorohydrin to obtain a multifunctional epoxy resin, reacting the obtained multifunctional epoxy resin with (meth)acrylic acid, and adding a dibasic acid anhydride to the generated hydroxyl groups. The bifunctional epoxy resin is preferably a solid.

[0033] (3) A carboxyl-containing photosensitive resin obtained by reacting a bisphenol A epoxy resin or a bisphenol F epoxy resin with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule and a monocarboxylic acid containing an unsaturated group such as (meth) acrylic acid, so that the alcoholic hydroxyl group of the obtained reaction product reacts with a polybasic acid anhydride such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, or adipic anhydride.

[0034] (4) A carboxyl group-containing photosensitive resin obtained by reacting a reaction product obtained by reacting a condensate of bisphenol A or bisphenol F with an aldehyde with an alkylene oxide such as ethylene oxide or propylene oxide with an unsaturated group-containing monocarboxylic acid such as (meth)acrylic acid, and then reacting the resulting reaction product with a polyacid anhydride.

[0035] (5) A carboxyl group-containing photosensitive resin obtained by reacting a reaction product obtained by reacting bisphenol A or bisphenol F with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate with an unsaturated group-containing monocarboxylic acid, and then reacting the reaction product with a polybasic acid anhydride.

[0036] (6) A carbamate resin containing terminal carboxyl groups obtained by reacting the ends of the obtained carbamate resin with an acid anhydride to obtain a carbamate resin by polyaddition reaction of a diisocyanate compound such as an aliphatic diisocyanate, a branched aliphatic diisocyanate, an alicyclic diisocyanate, an aromatic diisocyanate, and a diol compound such as a polycarbonate polyol, a polyether polyol, a polyester polyol, a polyolefin polyol, an acrylic polyol, a bisphenol A-based alkylene oxide adduct diol, and a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

[0037] (7) In the synthesis of carboxyl-containing urethane resins obtained by the addition polymerization reaction of diisocyanates with carboxyl-containing diol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid and diol compounds, a carboxyl-containing urethane resin is terminally (meth)acrylated by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule such as (meth)acrylate.

[0038] (8) In the synthesis of a carboxyl group-containing urethane resin obtained by the polyaddition reaction of a diisocyanate, a carboxyl group-containing diol compound and a diol compound, a carboxyl group-containing urethane resin is obtained by adding an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate to a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule to obtain a terminal (meth)acryloyl carboxyl group-containing urethane resin.

[0039] (9) A carboxyl group-containing photosensitive resin obtained by adding a compound having a cyclic ether group and a (meth)acryloyl group in one molecule to any of the carboxyl group-containing resins described in (1) to (8).

[0040] (A) As the alkali-soluble resin having a structure other than the alkali-soluble resin, the following compounds (either oligomers or polymers) may be mentioned.

[0041] (10) Carboxyl group-containing photosensitive resins obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with unsaturated group-containing compounds such as styrene, α-methylstyrene, lower alkyl (meth)acrylates, and isobutylene.

[0042] (11) A carboxyl-containing photosensitive resin is obtained by reacting a polyfunctional oxetane resin described later with a dicarboxylic acid such as adipic acid, phthalic acid, or hexahydrophthalic acid, and adding a dibasic acid anhydride to the generated primary hydroxyl group to obtain a carboxyl-containing polyester resin. A compound having one epoxy group and one or more (meth)acryloyl groups in one molecule, such as (meth)acrylate glycidyl ester or (meth)acrylate α-methylglycidyl ester, is further added to the obtained carboxyl-containing polyester resin.

[0043] (12) A carboxyl group-containing photosensitive resin obtained by adding a compound having a cyclic ether group and a (meth)acryloyl group in one molecule to the carboxyl group-containing resin of (10) or (11).

[0044] It should be noted that the term "(meth)acrylate" herein refers to a term that collectively refers to acrylate, methacrylate, and a mixture thereof, and the same applies to other similar expressions hereinafter.

[0045] The acid value of the carboxyl group-containing resin is preferably 40 to 150 mgKOH / g. By setting the acid value of the carboxyl group-containing resin to 40 mgKOH / g or higher, alkaline development is improved. Furthermore, by setting the acid value to 150 mgKOH / g or lower, a normal resist pattern can be easily drawn. More preferably, it is 50 to 130 mgKOH / g.

[0046] The amount of the alkali-soluble resin (A) in the total composition is preferably 15 to 35% by mass. When the amount is 15 to 35% by mass, the coating film strength is good, the viscosity of the composition is moderate, and the coating properties are improved.

[0047] [(B) Photopolymerization initiator]

[0048] As the (B) photopolymerization initiator, any photopolymerization initiator known as a photopolymerization initiator or a photoradical generator can be used, and examples thereof include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethylphenylphosphine oxide, and bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide. Bisacylphosphine oxides such as 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine oxide, methyl 2,4,6-trimethylbenzoyldiphenylphosphine oxide, isopropyl pivaloylphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide; monoacylphosphine oxides such as 1-hydroxy-cyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propane-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1-one. benzophenones such as benzophenone, benzoyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether, etc.; benzoin alkyl ethers; benzophenones such as benzophenone, p-methyl benzophenone, Michler's ketone, methyl benzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone, etc.; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylthio)phenyl Acetophenones such as (amino)-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone and N,N-dimethylaminoacetophenone; thioxanthones such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone; anthraquinones such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzil dimethyl ketal; benzoates such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, and ethyl p-dimethylbenzoate;Oxime esters such as 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime) and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetooxime); titanocenes such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium and bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyrrol-1-yl)ethyl)phenyl]titanium; phenyl disulfide 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, and tetramethylthiuram disulfide. Photopolymerization initiators may be used alone or in combination of two or more.

[0049] The amount of the photopolymerization initiator (B) is preferably 8 to 15 parts by mass relative to 100 parts by mass of the alkali-soluble resin (A). Within this range, surface curability is improved, halation is less likely to occur, and good resolution can be achieved.

[0050] [(C) Epoxy resin having an isocyanurate structure]

[0051] The curable composition of the present invention contains an epoxy resin having an isocyanurate structure, wherein the nitrogen atom in the isocyanurate structure is bonded to the epoxy group via an alkylene chain having 2 or more carbon atoms. Epoxy resins having an alkylene chain having 2 or more and 5 or less carbon atoms are particularly preferred. If the alkylene chain has 2 to 5 carbon atoms, the cured product obtained from the curable composition can achieve both effective flux resistance and flex resistance. Furthermore, the inherent developability of the curable composition can be maintained.

[0052] The epoxy resin (C) having an isocyanurate structure used in the present invention preferably has a structure represented by the following formula (I).

[0053]

[0054] (In formula (1),

[0055] R1, R2 and R3 each independently represent an alkylene group having 2 to 5 carbon atoms,

[0056] n is 0 or 1, but not all n are 0 at the same time)

[0057] Among them, a structure in which R1, R2 and R3 in formula (1) are simultaneously an alkylene group having 3 carbon atoms and n is simultaneously 1 is particularly preferred.

[0058] Specific examples of the epoxy resin (C) having an isocyanurate structure preferably used in the present invention include TEPIC (registered trademark)-VL and TEPIC (registered trademark)-FL (both manufactured by Nissan Chemical Industries, Ltd.).

[0059] The amount of the epoxy resin (C) having an isocyanurate structure is preferably 5 to 15 parts by mass relative to 100 parts by mass of the carboxyl group-containing resin (A). Within this range, the cured product can be provided with both excellent flux resistance and flex resistance while maintaining the inherent developability of the curable composition.

[0060] [Inorganic fillers]

[0061] The curable composition of the present invention may contain an inorganic filler in order to suppress its curing shrinkage and improve properties such as adhesion and hardness.

[0062] The inorganic filler is not particularly limited, and known and commonly used fillers can be used, for example, silica, crystalline silica, Neuburg silica, aluminum hydroxide, glass powder, talc, clay, magnesium carbonate, calcium carbonate, natural mica, synthetic mica, aluminum hydroxide, barium sulfate, barium titanate, iron oxide, non-fibrous glass, hydrotalcite, mineral wool, aluminum silicate, calcium silicate, zinc oxide, etc. Among them, silica is preferred, and spherical silica is more preferred because it has a small surface area and disperses stress over the entire surface, making it less likely to become a starting point for cracks.

[0063] For inorganic filler, photoreactive surface treatment can be carried out to have vinyl, styryl, methacryloyl, acryloyl etc. as photocurable reaction group, in this case, particularly preferably methacryloyl, acryloyl, vinyl. In addition, thermally reactive surface treatment can be carried out to have hydroxyl, carboxyl, isocyanate, amino, imino, epoxy, oxetane, sulfhydryl, methoxymethyl, methoxyethyl, ethoxymethyl, ethoxyethyl, oxazoline etc. as thermally curable reaction group, in this case, particularly preferably amino, epoxy. And then, inorganic filler can have more than two kinds of curable reaction groups. As inorganic filler, preferably surface-treated silica. By comprising surface-treated silica, thus can reduce CTE, raise glass transition temperature.

[0064] The method for introducing curable reactive groups into the surface of the inorganic filler is not particularly limited and can be introduced by a known common method. The surface of the inorganic filler can be treated with a surface treatment agent having curable reactive groups, such as a coupling agent having curable reactive groups.

[0065] As the surface treatment of the inorganic filler, surface treatment using a coupling agent is preferred. As the coupling agent, a silane coupling agent, a titanium coupling agent, a zirconium coupling agent, an aluminum coupling agent, etc. can be used. Among them, a silane coupling agent is preferred.

[0066] As silane coupling agents, those capable of introducing curing-reactive groups into inorganic fillers are preferred. Silane coupling agents capable of introducing thermosetting-reactive groups include those having epoxy groups, amino groups, mercapto groups, and isocyanate groups, with epoxy groups being more preferred. Silane coupling agents capable of introducing photocuring-reactive groups include those having vinyl groups, styryl groups, methacryl groups, and acryl groups, with methacryl groups being more preferred.

[0067] When the inorganic filler is surface-treated, it can be mixed with the curable resin composition of the present invention in a surface-treated state. The surface-untreated inorganic filler and the surface treatment agent can be mixed separately and the inorganic filler is surface-treated in the composition, but it is preferred to pre-mix the surface-treated inorganic filler. By mixing the inorganic filler that has been surface-treated in advance, it is possible to prevent the reduction of crack resistance and the like caused by the surface treatment agent that is not consumed during the surface treatment and that may remain when mixed separately. When the surface treatment is performed in advance, it is preferred to mix a pre-dispersion liquid in which the inorganic filler is pre-dispersed in a solvent or a resin component. More preferably, the surface-treated inorganic filler is pre-dispersed in a solvent and the pre-dispersion liquid is mixed with the composition; or the surface-untreated inorganic filler is pre-dispersed in a solvent and the pre-dispersion liquid is fully surface-treated and then mixed with the composition.

[0068] In the curable composition of the present invention, the average particle size of the inorganic filler is preferably 1 μm or less from the perspective of achieving better crack resistance. More preferably, it is 0.8 μm or less. 50 The value of is, for example, a value measured using a Microtrac particle size analyzer manufactured by Nikkiso Co., Ltd.

[0069] In addition, from the perspective of efficient reaction and excellent crack resistance and adhesion, the maximum particle size of the inorganic filler is preferably 4.0 μm or less. More preferably, it is 3.0 μm or less. It should be noted that in this specification, the maximum particle size refers to D 100 The value of is, for example, a value measured using a Microtrac particle size analyzer manufactured by Nikkiso Co., Ltd.

[0070] When the curable composition of the present invention contains an inorganic filler, the amount of the inorganic filler blended is preferably 15 to 35 parts by mass based on 100 parts by mass of the solid content of the curable composition.

[0071] [Powder or crystalline epoxy resin]

[0072] The curable composition of the present invention preferably contains an epoxy resin, and particularly preferably contains a powdered or crystalline epoxy resin, as this further improves the flux resistance of the cured product.

[0073] Powdered or crystalline epoxy resins are highly crystalline epoxy resins that are solid resins with well-ordered polymer chains at temperatures below their melting point and thermosetting epoxy resins with low viscosity equivalent to liquid resins when melted.

[0074] As the powder or crystalline epoxy resin, a crystalline epoxy resin having any of a biphenyl structure, a sulfide structure, a phenylene structure, and a naphthylene structure is preferably used.

[0075] Biphenyl type epoxy resins are available as, for example, "jER (registered trademark) YX4000", "jER (registered trademark) YX4000H", "jER (registered trademark) YL6121H", "jER (registered trademark) YL6640", and "jER (registered trademark) YL6677" manufactured by Mitsubishi Chemical Corporation; diphenyl sulfide type epoxy resins are available as, for example, "Epototo (registered trademark) YSLV-120TE" manufactured by NIPPON STEEL Chemical & Material Co., Ltd.; and phenylene type epoxy resins are available as, for example, "NIPPON STEEL Chemical & Material" manufactured by Co., Ltd., "Epototo (registered trademark) YDC-1312," and naphthylene-type epoxy resins are available as, for example, "Epiclon (registered trademark) HP-4032," "Epiclon (registered trademark) HP-4032D," and "Epiclon (registered trademark) HP-4700" manufactured by DIC Corporation. In addition, powdered or crystalline epoxy resins such as "Epototo (registered trademark) YSLV-90C" manufactured by Nippon Steel Chemical & Material Co., Ltd. and "TEPIC-S" (triglycidyl isocyanurate) manufactured by Nissan Chemical Co., Ltd. can also be used. Among these, "jER (registered trademark) YX4000" manufactured by Mitsubishi Chemical Corporation, a biphenyl-type epoxy resin, is preferred due to its excellent solder heat resistance.

[0076] In the curable composition of the present invention, these powders or crystalline epoxy compounds may be used alone or in combination of two or more.

[0077] The amount of the powder or crystalline epoxy resin to be added is preferably 20 to 40 parts by mass based on solid content relative to 100 parts by mass of the (A) alkali-soluble resin.

[0078] When the amount of the powder or crystalline epoxy resin added is within the above range, developability and flux resistance become further improved.

[0079] Furthermore, the curable composition of the present invention may, of course, further contain an epoxy resin other than the powdery or crystalline epoxy resin in order to improve heat resistance.

[0080] Examples of such epoxy resins include amorphous cresol novolac epoxy resins (specifically, EPICLON N-695 manufactured by DIC Corporation), amorphous phenol novolac epoxy resins (specifically, EPICLON N-775 manufactured by DIC Corporation), amorphous bisphenol A novolac epoxy resins (specifically, EPICLON N-865 manufactured by DIC Corporation), amorphous bisphenol A epoxy resins (specifically, jER1001 manufactured by Mitsubishi Chemical Corporation), amorphous bisphenol F epoxy resins (specifically, jER4004P manufactured by Mitsubishi Chemical Corporation), amorphous bisphenol S epoxy resins (specifically, EPICLON N-865 manufactured by DIC Corporation), and amorphous bisphenol A epoxy resins. EXA-1514), non-crystalline bisphenol AD ​​type epoxy resin, non-crystalline hydrogenated bisphenol A type epoxy resin, non-crystalline biphenyl novolac type epoxy resin, and non-crystalline special bifunctional epoxy resin (as specific examples, non-crystalline epoxy resins such as product numbers YL7175-500 and YL7175-1000 manufactured by Mitsubishi Chemical Corporation; and product names EPICLON TSR-960, EPICLON TER-601, EPICLON TSR-250-80BX, EPICLON 1650-75MPX, EPICLON EXA-4850, EPICLON EXA-4816, EPICLON EXA-4822, and EPICLON EXA-9726 manufactured by DIC Corporation).

[0081] Alternatively, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol AF epoxy resin, or phenol novolac epoxy resin may be mentioned. Specific examples of liquid epoxy resins include liquid epoxy resins such as "EXA4032SS," "HP4032SS," and "EXA-7311G4S" (naphthylene epoxy resins) manufactured by DIC Corporation, and "jER828EL" (bisphenol A epoxy resin), "jER807" (bisphenol F epoxy resin), "jER152" (phenol novolac epoxy resin), and "YL7223" and "YL7723" (bisphenol AF epoxy resins) manufactured by Mitsubishi Chemical Corporation.

[0082] Further examples include solid epoxy resins such as tetrafunctional naphthylene epoxy resins, cresol novolac epoxy resins, dicyclopentadiene epoxy resins, trisphenol epoxy resins, naphthol novolac epoxy resins, biphenyl epoxy resins, and naphthyl ether epoxy resins. Among these, tetrafunctional naphthylene epoxy resins, biphenyl epoxy resins, and naphthyl ether epoxy resins are more preferred, and biphenyl epoxy resins are even more preferred. Specific examples of such solid epoxy resins include “HP-4710” (a tetrafunctional naphthylene-type epoxy resin), “EXA7311”, “EXA7311-G3”, and “HP6000” (naphthyl ether-type epoxy resins) manufactured by DIC Corporation, “EPPN-502H” (a trisphenol epoxy resin), “NC7000L” (a naphthol novolac epoxy resin), “NC3000H”, “NC3000”, “NC3000L”, and “NC3100” (a biphenyl-type epoxy resin) manufactured by Nippon Kayaku Co., Ltd., “ESN475” and “ESN485” (naphthol novolac-type epoxy resins) manufactured by NIPPON STEEL Chemical & Material Co., Ltd., and (a bixylenol-type epoxy resin) manufactured by Mitsubishi Chemical Corporation.

[0083] Here, the curable composition of the present invention preferably contains an epoxy resin having a dicyclopentadiene structure as an epoxy resin other than a powdered or crystalline epoxy resin. Examples of such epoxy resins include "HP7200," "HP7200H," "HP7200K," and "HP7200L" manufactured by DIC Corporation.

[0084] The mass ratio of the epoxy resin (C) having an isocyanurate structure to the powder or crystalline epoxy resin to the epoxy resin having a dicyclopentadiene structure is particularly preferably 1:2 to 6:1 to 3. Within this numerical range, the curable composition of the present invention exhibits optimal flux resistance and flexural properties.

[0085] The mixing ratio of the powder or crystalline epoxy resin to other epoxy resins is preferably in the range of 5:1 to 1:5 in terms of mass ratio.

[0086] [Urethane beads / epoxidized polybutadiene]

[0087] The curable composition of the present invention preferably contains urethane beads and / or epoxidized polybutadiene to improve flexibility. In particular, the inclusion of epoxidized polybutadiene further improves the bendability of the cured product.

[0088] The amount of the urethane beads added is preferably 20 to 35 parts by mass relative to 100 parts by mass of the (A) alkali-soluble resin.

[0089] The amount of the epoxidized polybutadiene added is preferably 8 parts by mass or more and 12 parts by mass or less relative to 100 parts by mass of the (A) alkali-soluble resin.

[0090] [Cellulose resin]

[0091] The curable composition of the present invention preferably contains a cellulose resin.

[0092] By including a cellulose resin, the amount of liquid components (such as liquid epoxy resin and monomer components) can be increased, thereby making it easier to ensure flux resistance and also achieving the effect of suppressing tackiness during light exposure.

[0093] The amount of the cellulose resin to be added is preferably 5 to 10 parts by mass relative to 100 parts by mass of the (A) alkali-soluble resin.

[0094] [Colorant]

[0095] The curable composition of the present invention may contain a colorant. Specific examples of colorants include phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, leuco crystal violet, carbon black, naphthalene black, and solvent blue. The colorant may be used alone or in combination of two or more.

[0096] The amount of the colorant added is not particularly limited, but a ratio of preferably 7 to 15 parts by mass relative to 100 parts by mass of the (A) alkali-soluble resin is sufficient.

[0097] [Organic solvents]

[0098] Furthermore, the curable composition of the present invention may contain an organic solvent for the purpose of preparing the composition or adjusting the viscosity when applying the composition to a substrate or a carrier film.

[0099] Examples of such organic solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, and tripropylene glycol monomethyl ether; esters such as ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha. These organic solvents may be used alone or in combination of two or more.

[0100] [Compounds having an ethylenically unsaturated group]

[0101] The curable composition of the present invention preferably further contains a compound having an ethylenically unsaturated group as a reactive diluent. Examples of the compound having an ethylenically unsaturated group include compounds having a monofunctional or bifunctional (meth)acryloyl group.

[0102] Examples of monofunctional (meth)acryloyl compounds include aliphatic (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, hydroxypropyl (meth)acrylate, butoxymethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, isodecyl (meth)acrylate, and glycerol mono(meth)acrylate, cyclohexyl (meth)acrylate, 4-(meth)acryloyloxytricyclo[5.2.1.02,6]decyl alicyclic (meth)acrylates such as alkyl, isobornyl (meth)acrylate, aromatic (meth)acrylates such as phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate, modified (meth)acrylates such as aliphatic epoxy-modified (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-(meth)acryloyloxyalkyl phosphate, 2-(meth)acryloyloxyethyl phosphate, (meth)acryloyloxyethyl phthalate, and γ-(meth)acryloyloxyalkyltrialkoxysilane.

[0103] Specific examples of the compound having a bifunctional (meth)acryloyl group include diol diacrylates such as 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, and 1,10-decanediol diacrylate; ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, neopentyl glycol diacrylate, diol diacrylates obtained by adding at least one of ethylene oxide and propylene oxide to neopentyl glycol; diol diacrylates such as caprolactone-modified hydroxypivalic acid neopentyl glycol diacrylate; bisphenol A EO adduct diacrylate; and bisphenol A. Diacrylates having a cyclic structure such as PO adduct diacrylate, tricyclodecane dimethanol diacrylate, hydrogenated dicyclopentadienyl diacrylate, and cyclohexyl diacrylate.

[0104] Specific examples of compounds having three or more functional (meth)acryloyl groups include alkylene polyol poly(meth)acrylates such as pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; and polyoxyalkylene glycol poly(meth)acrylates such as propoxylated trimethylolpropane tri(meth)acrylate.

[0105] The amount of the compound having an ethylenically unsaturated group to be added is preferably 20 to 40 parts by mass relative to 100 parts by mass of the (A) alkali-soluble resin.

[0106] [Thermal Curing Catalyst]

[0107] The curable composition of the present invention may contain a thermal curing catalyst in order to improve its storage stability and heat resistance.

[0108] Examples of such a heat curing catalyst include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; amine compounds such as dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, and 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; and phosphorus compounds such as triphenylphosphine. In addition, s-triazine derivatives such as guanamine, methylguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-s-triazine, 2-vinyl-2,4-diamino-s-triazine, 2-vinyl-4,6-diamino-s-triazine / isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-s-triazine / isocyanuric acid adduct can also be used.

[0109] The amount of the thermosetting catalyst to be added is preferably 2.0 to 4.5 parts by mass relative to 100 parts by mass of the (A) alkali-soluble resin.

[0110] [Other ingredients]

[0111] The curable composition of the present invention may also contain other commonly used additives known in the field of electronic materials. Examples of such additives include thermal polymerization inhibitors, ultraviolet absorbers, silane coupling agents, plasticizers, flame retardants, antistatic agents, antioxidants, antibacterial / antifungal agents, leveling agents, thickeners, adhesion-imparting agents, thixotropy-imparting agents, photoinitiator aids, sensitizers, photobase generators, thermoplastic resins, organic fillers such as elastomers, mold release agents, surface treatment agents, dispersants, dispersing aids, surface modifiers, stabilizers, and phosphors.

[0112] [Dry film]

[0113] The curable composition of the present invention can also be used in the form of a dry film. The dry film of the present invention comprises a resin layer obtained by coating the curable composition of the present invention on a carrier film and drying the coating.

[0114] To form a dry film, the curable composition of the present invention is first diluted with the aforementioned organic solvent and adjusted to an appropriate viscosity. The composition is then applied to a carrier film in a uniform thickness using a comma coater, blade coater, lip coater, rod coater, die coater, reverse coater, transfer roll coater, gravure coater, spray coater, or the like. The applied composition is then dried, typically at a temperature of 40 to 130°C for 1 to 30 minutes, to form a resin layer. The coating film thickness is not particularly limited, but is generally selected within the range of 3 to 150 μm, preferably 5 to 60 μm, based on the dried film thickness.

[0115] As the carrier film, a plastic film can be used, for example, polyester films such as polyethylene terephthalate (PET), polyimide films, polyamide-imide films, polypropylene films, polystyrene films, etc. The thickness of the carrier film is not particularly limited, but is generally selected within the range of 10 to 150 μm, more preferably within the range of 15 to 130 μm.

[0116] After forming a resin layer comprising the curable composition of the present invention on a carrier film, it is preferable to further laminate a removable protective film on the surface of the resin layer to prevent dust from adhering to the surface of the resin layer. Examples of removable protective films include polyethylene films, polytetrafluoroethylene films, polypropylene films, and surface-treated paper. The protective film may be any film as long as its adhesive strength is less than that of the resin layer and the carrier film when the protective film is peeled off.

[0117] In the present invention, the curable composition of the present invention may be applied to the protective film and dried to form a resin layer, and a carrier film may be laminated on the surface of the resin layer. Specifically, when producing the dry film of the present invention, either a carrier film or a protective film may be used as the film to which the curable composition of the present invention is applied.

[0118] [cured material]

[0119] When a cured product is formed using the curable composition of the present invention, the composition is applied to a substrate, the solvent is evaporated and dried to obtain a resin layer, and the obtained resin layer is exposed (light irradiated) to cure the exposed portion (the portion after light irradiation). Specifically, a contact or non-contact method is used to selectively expose the product using active energy rays through a photomask having a pattern, or a laser direct exposure machine is used to directly expose the pattern, and an alkaline aqueous solution (such as a 0.3 to 3% sodium carbonate aqueous solution) is used to develop the unexposed portion to form a resist pattern. The product is then heated to a temperature of about 100 to 180°C for thermal curing (post-curing), thereby forming a cured film (cured product) having excellent properties such as heat resistance, chemical resistance, moisture absorption resistance, adhesion, and electrical properties.

[0120] The curable composition of the present invention can be applied to a substrate using, for example, the aforementioned organic solvent, adjusted to a viscosity suitable for the coating method, and then applied to the substrate by dip coating, flow coating, roll coating, bar coating, screen printing, curtain coating, or the like. The organic solvent contained in the composition is then volatilized and dried at a temperature of approximately 60 to 100°C (temporary drying) to form a tack-free resin layer. Alternatively, when the curable composition is applied to a carrier film or protective film, dried, and wound up as a dry film, the resin layer of the dry film of the present invention can be laminated to the substrate using a laminator or the like so that the resin layer is in contact with the substrate, and the carrier film is removed to thereby laminate the resin layer onto the substrate.

[0121] As a substrate, in addition to printed circuit boards and flexible printed circuit boards with circuits pre-formed from copper or the like, there can also be mentioned: copper-clad laminates of all grades (FR-4, etc.), as well as metal substrates, polyimide films, PET films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer plates, etc. The copper-clad laminates are made of materials such as copper-clad laminates for high-frequency circuits using paper phenol resin, paper epoxy resin, glass cloth epoxy resin, glass polyimide, glass cloth / non-woven fabric epoxy resin, glass cloth / paper epoxy resin, synthetic fiber epoxy resin, fluororesin / polyethylene / polyphenylene ether, polyphenylene ether / cyanate ester, etc.

[0122] The volatilization drying or thermal curing can be performed using a hot air circulation drying furnace, IR furnace, hot plate, convection oven, etc. (a method using a heat source with steam-based air heating method to make hot air convection contact in the dryer and a method of blowing from a nozzle to the support).

[0123] As the exposure machine used in the above-mentioned active energy ray irradiation, any device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, etc., and irradiating active energy rays in the range of 350 to 450 nm can be used. In addition, a direct drawing device (for example, a laser direct imaging device that directly draws an image with a laser based on CAD data from a computer) can also be used. As a lamp light source or a laser light source of a direct drawing machine, the maximum wavelength can be in the range of 350 to 410 nm. The exposure amount used for image formation varies depending on the film thickness, etc., and is usually set to 20 to 1000 mJ / cm 2 , preferably 20 to 800 mJ / cm 2 within the range.

[0124] The development method may be based on immersion, showering, spraying, brushing, etc., and the developer may be an aqueous alkali solution of potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, etc.

[0125] The curable composition of the present invention is suitable for forming a surface protective film such as a solder resist layer on a flexible printed circuit board. Note that the curable composition of the present invention can also be used as an interlayer insulating layer of a multilayer printed circuit board.

[0126] [Electronic components]

[0127] The present invention also provides an electronic component comprising a cured product obtained by curing the curable composition of the present invention. By using the curable composition of the present invention, an electronic component having high quality, durability, and reliability is provided.

[0128] It should be noted that the electronic components in the present invention refer to components used in electronic circuits, and include active components such as printed circuit 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 present invention exhibits the effects of the present invention as these insulating cured coating films.

[0129] It should be noted that the flux in which the cured product of the present invention shows good resistance includes all existing compositions and formulations based on rosin. As examples of some of such fluxes, SF-270, SF-360PF-1, SRM-800G (all manufactured by Sanwa Kagaku Corp.), JS-E-15X, JS-EU-31 (all manufactured by KOKI Company Ltd.), NS-F850-8, NS-F901, NS-334, NS-316F-8 (manufactured by Nippon Superior Co., Ltd.), etc. can be cited.

[0130] Hereinafter, one embodiment of the present invention will be specifically described based on an embodiment, but it is of course not intended to limit the scope of protection of the claims of this application.

[0131] Example

[0132] <Synthesis Example 1. Preparation of Carboxyl Group-Containing Acrylate Resin (Bisphenol A Structure)>

[0133] In a flask equipped with a condenser and a stirrer, 456 parts of bisphenol A, 228 parts of water, and 649 parts of 37% formaldehyde were added. Maintaining the temperature below 40°C, 228 parts of a 25% aqueous sodium hydroxide solution were added and reacted at 50°C for 10 hours. After the reaction, the mixture was cooled to 40°C and neutralized to pH 4 with a 37.5% aqueous phosphoric acid solution while maintaining the temperature below 40°C. The mixture was then allowed to stand and the aqueous layer separated. After separation, 300 parts of methyl isobutyl ketone was added and uniformly dissolved. The mixture was then washed three times with 500 parts of distilled water. Water and the solvent were then removed under reduced pressure at a temperature below 50°C. The resulting polymethylol compound was dissolved in 550 parts of methanol to obtain 1230 parts of a methanol solution of the polymethylol compound.

[0134] A portion of the obtained methanol solution of the polymethylol compound was dried in a vacuum dryer at room temperature, whereupon the solid content was 55.2%.

[0135] In a flask equipped with a condenser and a stirrer, 500 parts of the obtained methanol solution of the polymethylol compound and 440 parts of 2,6-xylenol were placed and uniformly dissolved at 50°C. After uniform dissolution, the methanol was removed under reduced pressure at a temperature below 50°C. Then, 8 parts of oxalic acid was added, and the mixture was reacted at 100°C for 10 hours. After completion of the reaction, the fraction was removed at 180°C under a reduced pressure of 50 mmHg to obtain 550 parts of Novolac Resin A.

[0136] In an autoclave equipped with a thermometer, an alkylene oxide introduction device which also serves as a nitrogen introduction device, and a stirring device, 130 parts of novolac resin A, 2.6 parts of a 50% sodium hydroxide aqueous solution, and 100 parts of toluene / methyl isobutyl ketone (mass ratio = 2 / 1) were placed. The system was purged with nitrogen while stirring. Then, the temperature was raised to 150°C and 8 kg / cm 2 60 parts of propylene oxide were slowly introduced to react. The reaction was continued for about 4 hours until the gauge pressure reached 0.0 kg / cm 2 The mixture was then cooled to room temperature. 3.3 parts of a 36% aqueous hydrochloric acid solution was added to the reaction solution and mixed, followed by neutralization with sodium hydroxide. The neutralized reaction product was diluted with toluene, washed three times with water, and desolvated in an evaporator to obtain a propylene oxide adduct of novolac resin A having a hydroxyl value of 189 g / eq. This product was obtained by adding an average of 1 mol of propylene oxide per 1 equivalent of phenolic hydroxyl groups.

[0137] In a reactor equipped with a stirrer, a thermometer, and an air inlet tube, 189 parts of the obtained propylene oxide adduct of novolac resin A, 36 parts of acrylic acid, 3.0 parts of p-toluenesulfonic acid, 0.1 part of hydroquinone monomethyl ether, and 140 parts of toluene were placed. The mixture was stirred while blowing air in, and the temperature was raised to 115°C. The reaction was continued for 4 hours while distilling off the water produced by the reaction and toluene as an azeotropic mixture. The mixture was then cooled to room temperature. The resulting reaction solution was washed with a 5% aqueous NaCl solution, and after removing the toluene by vacuum distillation, diethylene glycol monoethyl ether acetate was added to obtain an acrylate resin solution having a solids content of 67%.

[0138] Next, 322 parts of the resulting acrylic resin solution, 0.1 part of hydroquinone monomethyl ether, and 0.3 part of triphenylphosphine were placed in a four-necked flask equipped with a stirrer and a reflux condenser. The mixture was heated to 110°C, and 60 parts of tetrahydrophthalic anhydride was added. The mixture was reacted for 4 hours, cooled, and then removed. The resulting photosensitive carboxyl-containing resin solution had a solids content of 70% and a solids acid value of 81 mgKOH / g.

[0139] <Synthesis Example 2. Preparation of Carboxyl Group-Containing Resin for Comparative Example>

[0140] A 2-liter separable flask equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen inlet tube was charged with 900 g of diethylene glycol dimethyl ether as a solvent and 21.4 g of t-butyl peroxy-2-ethylhexanoate (Perbutyl O, manufactured by NOF Corporation) as a polymerization initiator, and heated to 90°C. After heating, 309.9 g of methacrylic acid, 116.4 g of methyl methacrylate, 109.8 g of lactone-modified 2-hydroxyethyl methacrylate (Praxel FM1, manufactured by Daicel Chemical Industries, Ltd.), and 21.4 g of bis(4-tert-butylcyclohexyl) peroxydicarbonate (Peroyl TCP, manufactured by NOF Corporation) as a polymerization initiator were added dropwise over 3 hours. The mixture was then aged for 6 hours to obtain a carboxyl group-containing copolymer resin. The reaction was carried out under a nitrogen atmosphere.

[0141] Next, 363.9 g of 3,4-epoxycyclohexylmethyl acrylate (Cyclomer A200, manufactured by Daicel Chemical Co., Ltd.), 3.6 g of dimethylbenzylamine as a ring-opening catalyst, and 1.80 g of hydroquinone monomethyl ether as a polymerization inhibitor were added to the resulting carboxyl group-containing copolymer resin. The mixture was heated to 100° C. and stirred to effect an epoxy ring-opening addition reaction. After 16 hours, a solution containing 53.8% by weight (non-volatile content) of a carboxyl group-free resin having an acid value of 108.9 mgKOH / g and a weight-average molecular weight of 25,000, containing no aromatic rings, was obtained.

[0142] <Examples 1 to 7 and Comparative Examples 1 and 2>

[0143] The components and compounding amounts shown in Table 1 below were pre-mixed in a stirrer and then kneaded using a three-roll mill to obtain curable compositions of Examples 1 to 7 and Comparative Examples 1 and 2.

[0144] In addition, the numerical value of the compounding quantity in a table|surface shows the mass part of a solid content unless otherwise specified.

[0145] [Table 1]

[0146] Table 1. Components and blending amounts of curable compositions of Examples 1 to 7 and Comparative Examples 1 and 2

[0147]

[0148] *1Bisphenol F type acid-modified epoxy acrylate resin, alkali-soluble resin with bisphenol F structure (solid content 65%); ZFR-1401H; manufactured by Nippon Kayaku Co., Ltd.

[0149] *2 Composite acid-modified epoxy acrylate resin, alkali-soluble resin with urethane structure (solid content 52%); UXE-3000; manufactured by Nippon Kayaku Co., Ltd.

[0150] *3 Synthesis Example 1: Alkali-soluble resin with bisphenol A structure

[0151] *4 Alkali-soluble resins other than (A) alkali-soluble resins in the above-mentioned synthesis example 2

[0152] *5 CAP504-0.2; manufactured by Eastman Chemical

[0153] *6 Dicyandiamide; manufactured by Mitsubishi Chemical Corporation

[0154] *7 Paliogen Red K3580; manufactured by BASF Japan Co., Ltd.

[0155] *8 Firstgen blue 5380; manufactured by DIC Co., Ltd.

[0156] *9 Plast Yellow 8025; manufactured by Arimoto Chemical Industry Co., Ltd.

[0157] *10 Balck CK-T / SD-TT2259; Made by RESINO COLOR INDUSTRY CO., LTD.

[0158] *11 BYK-180; manufactured by BYK Japan Co.,Ltd.

[0159] *12 Silicon KS-66; manufactured by Shin-Etsu Silicone Co., Ltd.

[0160] *13 JMT-784; manufactured by DKSH Japan Co., Ltd.

[0161] *14Omirad379; manufactured by IGM Resins

[0162] *15 Exolit (registered trademark) OP935; manufactured by Clariant

[0163] *16 Erosil#R974; manufactured by Toshin Kasei Co., Ltd.

[0164] *17 Melamine; manufactured by Nissan Chemical Co., Ltd.

[0165] *18 UCN-5050D Clear; manufactured by Dainichi Seika Industries, Ltd.

[0166] *19 Dawanol DPM; manufactured by Dow Chemical Company

[0167] *20 EPOLEAD PB3600; manufactured by Daicel Co., Ltd.

[0168] *21 NK Ester APG-700; manufactured by Shin-Nakamura Chemical Industry Co., Ltd.

[0169] *22 BPE-900; manufactured by Shin-Nakamura Chemical Industry Co., Ltd.

[0170] *23 HP-7200L; made by DIC Co., Ltd.

[0171] *24 jER YX-4000; manufactured by Mitsubishi Chemical Corporation

[0172] *25 TEPIC (registered trademark)-VL; manufactured by Nissan Chemical Co., Ltd.

[0173] *26 TEPIC (registered trademark)-HP; manufactured by Nissan Chemical Co., Ltd.

[0174] Cured coating films (solder resist layers) were prepared from the curable compositions of Examples 1 to 7 and Comparative Examples 1 and 2 obtained in Table 1. The cured coating films were tested for flux resistance, developability, and flexural properties as described below.

[0175] <Test Example 1. Evaluation of Flux Resistance>

[0176] The curable compositions of Examples 1 to 7 and Comparative Examples 1 to 2 were applied to the entire surface of a 1.6 mm thick copper foil plate that had been pretreated (0.20 vol% sulfuric acid hydrogen peroxide) by screen printing to a film thickness of 20 ± 5 μm after drying. After drying in a hot air circulation drying oven at 80°C for 30 minutes, the film was exposed to light (150 mJ / cm2) in a 5 × 5 grid pattern of 1 mm each. 2 ), using 1wt% Na2CO3 alkaline developer (30℃), developing for 60 seconds, and then thermally curing at a temperature above 150℃ for 60 minutes to obtain the cured coating films of Examples 1 to 7 and Comparative Examples 1 to 2, respectively.

[0177] Each cured coating was then fully coated with flux (SF-270 manufactured by Sanwa Kagaku Corp.). A dummy wafer was placed on the top of the coating and heat treated once at a speed of 1.5 m / min for 5 minutes at 230°C in an air conveyor furnace. The cured coating was then peeled off using cellophane tape with a strength of 1.18 N / cm or greater as specified in JIS Z 1522:2009. The degree of peeling of the cured coating was evaluated as follows.

[0178] The peeling area after the peel test is less than 10%◎

[0179] The peeled area after the peel test is more than 10% and less than 50%○

[0180] After the peel test, the peeled area exceeds 50% and 100% ×

[0181] <Test Example 2. Developability>

[0182] The curable compositions of Examples 1-7 and Comparative Examples 1-2 were screen-printed onto the entire surface of a 1.6 mm thick copper foil plate that had been pretreated (0.20 vol% sulfuric acid hydrogen peroxide) to a film thickness of 20 ± 5 μm after drying. The films were then dried in a hot air circulation drying oven at 80°C for 30 minutes to obtain dried coatings of Examples 1-7 and Comparative Examples 1-2, respectively. The dried coatings were then developed in a 1 wt% Na2CO3 solution (at 30°C) using a spray method at a pressure of 0.1 MPa. The developing time (dissolution time) was measured to evaluate the developability. The evaluation is as follows.

[0183] Development time is less than 20 seconds◎

[0184] Development time: more than 20 seconds - less than 25 seconds

[0185] Development time 25 seconds or more ×

[0186] <Test Example 3. Bending Properties>

[0187] The curable compositions of Examples 1 to 7 and Comparative Examples 1 to 2 were applied to the entire surface of a 25 μm thick polyimide film by screen printing so that the film thickness after drying was 20 ± 5 μm. After drying in a hot air circulation drying oven at 80°C for 30 minutes, exposure (150 mJ / cm 2 ), using 1wt% Na2CO3 alkaline developer (30℃), developing for 60 seconds, and then thermally curing at a temperature above 150℃ for 60 minutes to obtain the cured coating films of Examples 1 to 7 and Comparative Examples 1 to 2, respectively.

[0188] Then, the film was bent 180 degrees, a 500 g weight was applied for 10 seconds, and the number of bends required until cracks occurred on the surface of the cured coating film was measured. Evaluation was as follows.

[0189] Bend more than 5 times◎

[0190] Bend more than 2 times○

[0191] Bend less than 2 times×

[0192] The test results of Test Examples 1 to 3 are shown in Table 2 below.

[0193] [Table 2]

[0194] Table 2. Test results

[0195]

Claims

1. A curable composition comprising: (A) an alkali-soluble resin, wherein the (A) alkali-soluble resin comprises an alkali-soluble resin having a bisphenol A structure, an alkali-soluble resin having a bisphenol F structure, and an alkali-soluble resin having a urethane structure; (B) a photopolymerization initiator; and (C) an epoxy resin having an isocyanurate structure, The epoxy resin (C) having an isocyanurate structure has a structure in which the nitrogen atom in the isocyanurate structure and the epoxy group are bonded via an alkylene chain having 2 to 5 carbon atoms. The compounding quantity of the said (C) epoxy resin which has an isocyanurate structure is 5-15 mass parts with respect to 100 mass parts of (A) alkali-soluble resins. 2 . The curable composition according to claim 1 , further comprising a powder or a crystalline epoxy resin.

3. The curable composition according to claim 2, wherein The powder or crystalline epoxy resin is an epoxy resin having a biphenyl structure. The curable composition according to claim 2 or 3, further comprising an epoxy resin having a dicyclopentadiene structure.

5. The curable composition according to claim 4, wherein The mass ratio of the epoxy resin (C) having an isocyanurate structure to the powder or crystalline epoxy resin to the epoxy resin having a dicyclopentadiene structure is 1:2-6:1-3. 6 . The curable composition according to claim 1 , further comprising urethane beads and / or epoxidized polybutadiene. 7 . The curable composition according to claim 1 , further comprising a cellulose resin. 8 . A dry film comprising a resin layer, wherein the resin layer is obtained from the curable composition according to claim 1 . 9 . A cured product obtained by curing the curable composition according to claim 1 or the resin layer of the dry film according to claim 8 . 10 . An electronic component comprising the cured product according to claim 9 .

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