Curable composition, dry film thereof, and cured product

Abstract

[Problem] To provide a curable composition capable of forming solder resists which combine flux resistance and folding endurance. [Solution] The curable composition comprises (A) an alkali-soluble resin having at least any one structure selected from among 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, wherein the epoxy resin (C) having an isocyanurate structure has a structure in which a nitrogen atom contained in the isocyanurate structure has been bonded to an epoxy group by an alkylene chain having two or more carbon atoms. [Selected drawing] None

Description

[Technical Field]

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

[0002] Conventionally, a solder resist (SR) is formed on a printed wiring board to protect the circuitry, and a semiconductor chip or the like is soldered (mounted) on the printed wiring board on which the solder resist is formed. An example of a composition for forming such a solder resist is a solder resist ink for circuit boards, which is based on a photosensitive resin composition containing a carboxyl group-containing photosensitive polymer, as described in Patent Document 1.

[0003] On the other hand, during soldering, flux is usually applied to the surface of the connecting circuit, and during the application process, the entire surface of the printed wiring board on which the solder resist is formed is exposed to the flux. This flux is used to remove oxides and dirt from the circuit connecting surface and prevent oxidation during heating, and also has the effect of lowering the surface tension of the molten solder, improving the wetting of the solder to the joint. On the other hand, in view of the fact that the use of so-called flexible printed wiring boards, which are used while being bent, is increasing, the solder resist formed on such wiring boards is also required to have a degree of flexibility that allows it to withstand bending. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-65117 Summary of the Invention [Problem to be solved by the invention]

[0005] In other words, solder resists are required to have flux resistance, i.e., the ability to maintain adhesion to the printed wiring board without peeling off even during high-temperature soldering treatment after application of flux.In addition, solder resists are also required to have bendability that prevents cracks from occurring even when the printed wiring board is bent.

[0006] However, in this regard, solder resists obtained from conventional compositions such as those described in Patent Document 1 are easily deteriorated by flux components and also have insufficient flexibility, making it difficult to simultaneously achieve flux resistance and bendability. [Means for solving the problem]

[0007] In view of the above, the present inventors have conducted extensive research and have found that a curable composition containing an alkali-soluble resin having a bisphenol A structure or the like and an epoxy resin with a specific structure having both an isocyanurate structure and an alkylene structure can form a solder resist that is both flux-resistant and bendable, thereby completing the present invention.

[0008] That is, the present invention provides: (A) an alkali-soluble resin having at least one structure selected from the group consisting of a bisphenol A structure, a bisphenol F structure, and a urethane structure; (B) a photopolymerization initiator; (C) an epoxy resin having an isocyanurate structure; A curable composition comprising: The (C) epoxy resin having an isocyanurate structure has a structure in which a nitrogen atom in the isocyanurate structure is bonded to an epoxy group via an alkylene chain having two or more carbon atoms. The present invention relates to the curable composition. A preferred embodiment of the present invention relates to a curable composition further comprising a powder or crystalline epoxy resin, preferably an epoxy resin having a biphenyl structure. A more preferred embodiment of the present invention also relates to a curable composition further comprising an epoxy resin having a dicyclopentadiene structure. A more preferred embodiment of the present invention relates to a curable composition, wherein the mass ratio of the (C) epoxy resin having an isocyanurate structure, the powdery or crystalline epoxy resin, and the epoxy resin having a dicyclopentadiene structure is 1:2 to 6:1 to 3. A more preferred embodiment of the present invention relates to a curable composition further comprising urethane beads and / or epoxidized polybutadiene. A more preferred embodiment of the present invention relates to a curable composition further comprising a cellulose resin. Another aspect of the present invention relates 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. [Effects of the Invention]

[0009] The present invention provides a curable composition capable of forming a solder resist having excellent flux resistance and bending properties. DETAILED DESCRIPTION OF THE INVENTION

[0010] Each component that can constitute the curable composition of the present invention will be described below.

[0011] [(A) Alkali-soluble resin] The alkali-soluble resin (A) used in the present invention has at least one structure selected from the group consisting of a bisphenol A structure, a bisphenol F structure, and a urethane structure. However, as will be described later, it is of course possible to use the alkali-soluble resin (A) in combination with an alkali-soluble resin having a structure other than these structures.

[0012] The (A) alkali-soluble resin is a resin that contains one or more functional groups selected from phenolic hydroxyl groups, thiol groups, and carboxyl groups and is soluble in an alkaline solution, and is preferably a compound having two or more phenolic hydroxyl groups, a carboxyl group-containing resin, a compound having a phenolic hydroxyl group and a carboxyl group, or a compound having two or more thiol groups. As the alkali-soluble resin, a carboxyl group-containing resin or a phenolic hydroxyl group-containing resin can be used, with a carboxyl group-containing resin being preferred.

[0013] The inclusion of carboxyl groups in the carboxyl group-containing resin allows it to be alkali-developable. Furthermore, from the viewpoint of photocurability and development resistance, it is preferable for the resin to have an ethylenically unsaturated group in addition to the carboxyl group in the molecule. However, it is also possible to use only a carboxyl group-containing resin without an ethylenically unsaturated group. The ethylenically unsaturated group is preferably derived from acrylic acid, methacrylic acid, or a derivative thereof. Among the carboxyl group-containing resins, preferred are carboxyl group-containing resins having a urethane structure, carboxyl group-containing resins made from bisphenol A epoxy resins or bisphenol F epoxy resins, and carboxyl group-containing resins made from bisphenol A or bisphenol F. Specific examples of carboxyl group-containing resins include the compounds (which may be either oligomers or polymers) listed below.

[0014] (1) A carboxyl group-containing photosensitive resin obtained by reacting bisphenol A epoxy resin or bisphenol F epoxy resin with (meth)acrylic acid and then adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the hydroxyl groups present in the side chains. Here, the bifunctional or higher polyfunctional epoxy resin is preferably solid.

[0015] (2) A carboxyl group-containing photosensitive resin obtained by reacting a polyfunctional epoxy resin in which the hydroxyl groups of a bisphenol A epoxy resin or a bisphenol F epoxy resin are further epoxidized with epichlorohydrin with (meth)acrylic acid, and then adding a dibasic acid anhydride to the resulting hydroxyl groups. Here, the difunctional epoxy resin is preferably solid.

[0016] (3) A carboxyl group-containing photosensitive resin obtained by reacting a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule with a bisphenol A type epoxy resin or a bisphenol F type epoxy resin, and an unsaturated group-containing monocarboxylic acid such as (meth)acrylic acid, and then reacting the alcoholic hydroxyl group of the resulting reaction product with a polybasic acid anhydride such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, or adipic acid.

[0017] (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 and 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 polybasic acid anhydride.

[0018] (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, reacting the reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0019] (6) A carboxyl-terminated urethane resin obtained by reacting an acid anhydride with the terminal of a urethane resin obtained by polyaddition reaction of a diisocyanate compound such as an aliphatic diisocyanate, a branched aliphatic diisocyanate, an alicyclic diisocyanate, or an aromatic diisocyanate with a diol compound such as a polycarbonate polyol, a polyether polyol, a polyester polyol, a polyolefin polyol, an acrylic polyol, a bisphenol A alkylene oxide adduct diol, or a compound having a phenolic hydroxyl group or an alcoholic hydroxyl group.

[0020] (7) A carboxyl group-containing urethane resin in which a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as a hydroxyalkyl (meth)acrylate, is added during the synthesis of the carboxyl group-containing urethane resin by polyaddition reaction of a diisocyanate with a carboxyl group-containing dialcohol compound such as dimethylolpropionic acid or dimethylolbutyric acid, and a diol compound, resulting in a (meth)acrylic-terminated carboxyl group-containing urethane resin.

[0021] (8) A carboxyl group-containing urethane resin obtained by adding a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as an equimolar reactant of isophorone diisocyanate and pentaerythritol triacrylate, during the synthesis of the carboxyl group-containing urethane resin by polyaddition reaction of a diisocyanate, a carboxyl group-containing dialcohol compound, and a diol compound, to form a (meth)acrylic-terminated carboxyl group-containing urethane resin.

[0022] (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 one of the carboxyl group-containing resins (1) to (8) above.

[0023] (A) Examples of the alkali-soluble resin having a structure other than the alkali-soluble resin include the compounds (which may be either oligomers or polymers) listed below. (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.

[0024] (11) A carboxyl group-containing photosensitive resin obtained by reacting a polyfunctional oxetane resin as described below with a dicarboxylic acid such as adipic acid, phthalic acid, or hexahydrophthalic acid, and then adding a dibasic acid anhydride to the resulting primary hydroxyl group to obtain a carboxyl group-containing polyester resin, to which a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule, such as glycidyl (meth)acrylate or α-methylglycidyl (meth)acrylate, is further added.

[0025] (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) above.

[0026] Here, (meth)acrylate is a general term for acrylate, methacrylate and mixtures thereof, and the same applies to other similar expressions hereinafter.

[0027] Here, the acid value of the carboxyl group-containing resin is preferably 40 to 150 mgKOH / g. By making the acid value of the carboxyl group-containing resin 40 mgKOH / g or more, alkaline development becomes favorable. Furthermore, by making the acid value 150 mgKOH / g or less, it becomes easier to draw a normal resist pattern. More preferably, it is 50 to 130 mgKOH / g.

[0028] The amount of the alkali-soluble resin (A) in the total composition is preferably 15 to 35% by mass, which provides good coating strength, appropriate viscosity of the composition, and improved coatability.

[0029] [(B) Photopolymerization initiator] 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, and bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide. bisacylphosphine oxides such as phosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, and methyl 2,4,6-trimethylbenzoylphenylphosphine acid; monoacylphosphine oxides such as 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid isopropyl ester, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; 1-hydroxy-cyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propane- hydroxyacetophenones such as benzoin, benzil, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and benzoin n-butyl ether; benzoin alkyl ethers; benzophenones such as benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bisdiethylaminobenzophenone;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-(dimethylamino)-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone acetophenones such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone anthraquinones such as acetophenone dimethyl ketal and 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzil dimethyl ketal; benzoic acid esters such as ethyl 4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate and p-dimethylbenzoic acid ethyl ester; 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime) Examples of photopolymerization initiators include oxime esters such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium and titanocenes such as bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyr-1-yl)ethyl)phenyl]titanium; phenyl disulfide 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, and tetramethylthiuram disulfide. The photopolymerization initiator may be used alone or in combination of two or more.

[0030] The blending amount of (B) photopolymerization initiator is preferably 8 to 15 parts by mass per 100 parts by mass of (A) alkali-soluble resin. Within this range, the surface curing property is good, halation is unlikely to occur, and good resolution can be obtained.

[0031] [(C) Epoxy resin having an isocyanurate structure] The curable composition of the present invention contains an epoxy resin having an isocyanurate structure, in which a nitrogen atom in the isocyanurate structure is bonded to an epoxy group via an alkylene chain having two or more carbon atoms. Epoxy resins having an alkylene chain with two or more to five carbon atoms are particularly preferred. When the alkylene chain has two to five carbon atoms, the cured product obtained from the curable composition can have both effective flux resistance and bendability. Furthermore, the inherent developability of the curable composition can be maintained.

[0032] The epoxy resin (C) having an isocyanurate structure used in the present invention preferably has a structure represented by the following formula (I). [ka] (In the formula, R1, R2, and R3 each independently represent an alkylene group having 2 to 5 carbon atoms; n is either 0 or 1, but not all n's are 0 at the same time.

[0033] Among these, particularly preferred is a structure in which R1, R2 and R3 simultaneously represent an alkylene group having 3 carbon atoms and n simultaneously represents 1 in the formula.

[0034] Specific examples of the epoxy resin having an isocyanurate structure (C) that is preferably used in the present invention include TEPIC (registered trademark)-VL and TEPIC (registered trademark)-FL (both manufactured by Nissan Chemical Industries, Ltd.).

[0035] The amount of the epoxy resin (C) having an isocyanurate structure is determined by the following formula: Alkali soluble The amount is preferably 5 to 15 parts by mass per 100 parts by mass of the resin. Within this range, not only can the cured product be simultaneously imparted with good flux resistance and bendability, but also the inherent developability of the curable composition can be maintained.

[0036] [Inorganic filler] The curable composition of the present invention may contain an inorganic filler in order to suppress cure shrinkage and improve properties such as adhesion and hardness. Such inorganic filler is not particularly limited, and known and commonly used fillers can be used, such as 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 these, silica is preferred, and spherical silica is more preferred because it has a small surface area and distributes stress throughout, making it less likely to become a starting point for cracks.

[0037] The inorganic filler may be surface-treated to be photoreactive so as to have a photocurable reactive group such as a vinyl group, a styryl group, a methacrylic group, or an acrylic group, with methacrylic, acrylic, or vinyl groups being particularly preferred. The inorganic filler may also be surface-treated to have a thermosetting reactive group such as a hydroxyl group, a carboxyl group, an isocyanate group, an amino group, an imino group, an epoxy group, an oxetanyl group, a mercapto group, a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an ethoxyethyl group, or an oxazoline group, with amino and epoxy groups being particularly preferred. Furthermore, the inorganic filler may have two or more types of curable reactive groups. Surface-treated silica is preferred as the inorganic filler. By including surface-treated silica, the CTE can be lowered and the glass transition temperature can be increased.

[0038] The method for introducing a curable reactive group onto the surface of an inorganic filler is not particularly limited, and the group may be introduced using a known, commonly used method, in which the surface of the inorganic filler is treated with a surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group.

[0039] The surface treatment of the inorganic filler is preferably a surface treatment with a coupling agent. Examples of the coupling agent that can be used include a silane coupling agent, a titanium coupling agent, a zirconium coupling agent, and an aluminum coupling agent. Among these, a silane coupling agent is preferred.

[0040] As the silane coupling agent, the silane coupling agent that can introduce curing reactive group into inorganic filler is preferred.As the silane coupling agent that can introduce thermosetting reactive group, the silane coupling agent that has epoxy group, the silane coupling agent that has amino group, the silane coupling agent that has mercapto group, the silane coupling agent that has isocyanate group can be mentioned, among which, the silane coupling agent that has epoxy group is more preferred.As the silane coupling agent that can introduce photocuring reactive group, the silane coupling agent that has vinyl group, the silane coupling agent that has styryl group, the silane coupling agent that has methacryl group, the silane coupling agent that has acrylic group is preferred, among which, the silane coupling agent that has methacryl group is more preferred.

[0041] When the inorganic filler is surface-treated, it is sufficient that it is blended in the curable resin composition of the present invention in a surface-treated state. Although the surface-untreated inorganic filler and the surface treatment agent may be blended separately to surface-treat the inorganic filler in the composition, it is preferable to blend an inorganic filler that has been surface-treated in advance. By blending an inorganic filler that has been surface-treated in advance, it is possible to prevent a decrease in crack resistance, etc., due to the surface treatment agent that may remain when blended separately and is not consumed in the surface treatment. When the inorganic filler is surface-treated in advance, it is preferable to blend a pre-dispersion in which the inorganic filler is pre-dispersed in a solvent or resin component. It is more preferable to pre-disperse the surface-treated inorganic filler in a solvent and then blend the pre-dispersion into the composition, or to pre-disperse the surface-untreated inorganic filler in a solvent, perform sufficient surface treatment, and then blend the pre-dispersion into the composition.

[0042] In the curable composition of the present invention, the inorganic filler preferably has an average particle size of 1 μm or less, as this provides better crack resistance. More preferably, it is 0.8 μm or less. In this specification, the average particle size refers to D 50 This is a value measured using, for example, a Microtrac particle size analyzer manufactured by Nikkiso Co., Ltd.

[0043] In addition, the inorganic filler preferably has a maximum particle size of 4.0 μm or less, as this allows for efficient reaction and provides superior crack resistance and adhesion. It is more preferably 3.0 μm or less. In this specification, the maximum particle size refers to D 100 This is a value measured using, for example, a Microtrac particle size analyzer manufactured by Nikkiso Co., Ltd.

[0044] When the curable composition of the present invention contains an inorganic filler, the amount of the inorganic filler to be blended is preferably 15 to 35 parts by mass per 100 parts by mass of the solid content of the curable composition.

[0045] [Powder or crystalline epoxy resin] The curable composition of the present invention preferably contains an epoxy resin, and particularly preferably contains a powder or crystalline epoxy resin, which can further improve the flux resistance of the cured product. Powder or crystalline epoxy resin refers to a highly crystalline epoxy resin, which is a thermosetting epoxy resin in which polymer chains are regularly arranged at temperatures below the melting point, and which, although being a solid resin, has a low viscosity comparable to that of a liquid resin when melted.

[0046] As the powder or crystalline epoxy resin, it is preferable to use a crystalline epoxy resin having any one of a biphenyl structure, a sulfide structure, a phenylene structure, and a naphthalene structure. Biphenyl-type epoxy resins are available, for example, from Mitsubishi Chemical Corporation under the names "jER (registered trademark) YX4000," "jER (registered trademark) YX4000H," "jER (registered trademark) YL6121H," "jER (registered trademark) YL6640," and "jER (registered trademark) YL6677." Diphenyl sulfide-type epoxy resins are available, for example, from Nippon Steel Chemical & Material Corporation under the name "Epotohto (registered trademark) YSLV-120TE." Phenylene-type epoxy resins are available, for example, from Nippon Steel Chemical & Material Corporation under the name "Epotohto (registered trademark) YDC-1312." Naphthalene-type epoxy resins are available, for example, from DIC Corporation under the names "EPICLON (registered trademark) HP-4032," "EPICLON (registered trademark) HP-4032D," and "EPICLON (registered trademark) HP-4700." Furthermore, as powder or crystalline epoxy resins, "Epotohto (registered trademark) YSLV-90C" manufactured by Nippon Steel Chemical & Material Co., Ltd. and "TEPIC-S" (triglycidyl isocyanurate) manufactured by Nissan Chemical Industries, Ltd. can also be used. Among these, "jER (registered trademark) YX4000" manufactured by Mitsubishi Chemical Corporation, which is a biphenyl-type epoxy resin, is preferred due to its excellent solder heat resistance properties. In the curable composition of the present invention, these powdery or crystalline epoxy compounds may be used alone or in combination of two or more.

[0047] The amount of such powder or crystalline epoxy resin to be blended is preferably 20 to 40 parts by mass based on the solid content per 100 parts by mass of the alkali-soluble resin (A). When the blending amount of the powder or crystalline epoxy resin is within the above range, the developability and flux resistance become better.

[0048] Furthermore, the curable composition of the present invention may, of course, further contain an epoxy resin other than the powder or crystalline epoxy resin in order to improve heat resistance. 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 (specifically, jER1001 manufactured by Mitsubishi Chemical Corporation). EXA-1514), amorphous bisphenol AD epoxy resins, amorphous hydrogenated bisphenol A epoxy resins, amorphous biphenyl novolac epoxy resins, and amorphous special bifunctional epoxy resins (specific examples include amorphous epoxy resins such as YL7175-500 and YL7175-1000 manufactured by Mitsubishi Chemical Corporation; 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).

[0049] Other examples include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol AF epoxy resins, and phenol novolac epoxy resins. Specific examples of liquid epoxy resins include "EXA4032SS," "HP4032SS," and "EXA-7311G4S" (naphthalene epoxy resins) manufactured by DIC Corporation, and "jER828EL" (bisphenol A epoxy resin), "jER807" (bisphenol F epoxy resin), "jER152" (phenol novolac epoxy resin), "YL7223," and "YL7723" (bisphenol AF epoxy resins) manufactured by Mitsubishi Chemical Corporation.

[0050] Further examples include solid epoxy resins such as tetrafunctional naphthalene epoxy resins, cresol novolac epoxy resins, dicyclopentadiene epoxy resins, trisphenol epoxy resins, naphthol novolac epoxy resins, biphenyl epoxy resins, and naphthylene ether epoxy resins. Of these, tetrafunctional naphthalene epoxy resins, biphenyl epoxy resins, and naphthylene ether epoxy resins are more preferred, and biphenyl epoxy resins are even more preferred. Specific examples of such solid epoxy resins include "HP-4710" (tetrafunctional naphthalene-type epoxy resin), "EXA7311", "EXA7311-G3", and "HP6000" (naphthylene ether-type epoxy resins) manufactured by DIC Corporation; "EPPN-502H" (trisphenol epoxy resin), "NC7000L" (naphthol novolac epoxy resin), "NC3000H", "NC3000", "NC3000L", and "NC3100" (biphenyl-type epoxy resins) manufactured by Nippon Kayaku Co., Ltd.; "ESN475" and "ESN485" (naphthol novolac-type epoxy resins) manufactured by Nippon Steel Chemical & Material Co., Ltd.; and (bixylenol-type epoxy resins) manufactured by Mitsubishi Chemical Corporation.

[0051] Here, the curable composition of the present invention preferably contains an epoxy resin having a dicyclopentadiene structure as an epoxy resin other than a powder or crystalline epoxy resin. Examples of such epoxy resins include "HP7200," "HP7200H," "HP7200K," and "HP7200L" manufactured by DIC Corporation. In particular, it is preferable that the mass ratio of the (C) epoxy resin having an isocyanurate structure, the powder or crystalline epoxy resin, and the epoxy resin having a dicyclopentadiene structure is 1:2 to 6:1 to 3. When the ratio is within this range, the curable composition of the present invention can exhibit the best flux resistance and bending properties.

[0052] The blending ratio of the powder or crystalline epoxy resin to the other epoxy resin is preferably in the range of 5:1 to 1:5 by mass.

[0053] [Urethane beads / epoxidized polybutadiene] 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 improves the foldability of the cured product. The amount of urethane beads to be blended is preferably 20 to 35 parts by mass per 100 parts by mass of the alkali-soluble resin (A). The amount of epoxidized polybutadiene to be blended is preferably 8 parts by mass or more and 12 parts by mass or less per 100 parts by mass of the alkali-soluble resin (A).

[0054] [Cellulose resin] The curable composition of the present invention preferably contains a cellulose resin. The inclusion of cellulose resin allows for an increase in the amount of liquid components (e.g., liquid epoxy resin or monomer components), which makes it easier to ensure flux resistance and also reduces tackiness during exposure. The blending amount of the cellulose resin is preferably 5 to 10 parts by mass per 100 parts by mass of the alkali-soluble resin (A).

[0055] [Coloring agent] The curable composition of the present invention may contain a colorant. Specific examples of colorants include phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, leucocrystal violet, carbon black, naphthalene black, and solvent blue. The colorants may be used alone or in combination of two or more.

[0056] There are no particular restrictions on the amount of colorant added, but a ratio of 7 to 15 parts by mass per 100 parts by mass of (A) the alkali-soluble resin is preferably sufficient.

[0057] [Organic solvents] The curable composition of the present invention may contain an organic solvent for the purpose of adjusting the viscosity when preparing the composition or when applying it to a substrate or a carrier film. Examples of such organic solvents that can be used 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.

[0058] [Compounds having an ethylenically unsaturated group] The curable composition of the present invention preferably further contains, as a reactive diluent, a compound having an ethylenically unsaturated group. Examples of the compound having an ethylenically unsaturated group include monofunctional or bifunctional compounds having a (meth)acryloyl group.

[0059] Examples of compounds having a monofunctional (meth)acryloyl group 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, and 4-(meth)acryloxytricyclo[5.2.1.02,6]decane. Examples of the methacrylate include alicyclic (meth)acrylates such as 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)acryloxyalkyl phosphate, 2-(meth)acryloyloxyethyl phosphate ester, (meth)acryloyloxyethyl phthalate, and γ-(meth)acryloxyalkyltrialkoxysilane.

[0060] 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, glycol diacrylates such as caprolactone-modified hydroxypivalic acid neopentyl glycol diacrylate, bisphenol A EO adduct diacrylate, and bisphenol A Examples include diacrylates having a cyclic structure such as PO adduct diacrylate, tricyclodecane dimethanol diacrylate, hydrogenated dicyclopentadienyl diacrylate, and cyclohexyl diacrylate. Specific examples of compounds having tri- or higher 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.

[0061] The amount of the compound having an ethylenically unsaturated group to be blended is preferably 20 to 40 parts by mass per 100 parts by mass of the alkali-soluble resin (A).

[0062] [Thermosetting catalyst] The curable composition of the present invention may contain a heat curing catalyst in order to improve its storage stability and heat resistance. Examples of such thermal curing catalysts 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, acetoguanamine, 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.

[0063] The amount of the thermosetting catalyst to be added is preferably 2.0 to 4.5 parts by mass per 100 parts by mass of the alkali-soluble resin (A).

[0064] [Other ingredients] The curable composition of the present invention may further contain other additives known and commonly used in the field of electronic materials, such as a thermal polymerization inhibitor, an ultraviolet absorber, a silane coupling agent, a plasticizer, a flame retardant, an antistatic agent, an antioxidant, an antibacterial and antifungal agent, a leveling agent, a thickener, an adhesion imparting agent, a thixotropy imparting agent, a photoinitiator aid, a sensitizer, a photobase generator, a thermoplastic resin, an organic filler such as an additional elastomer, a release agent, a surface treatment agent, a dispersant, a dispersion aid, a surface modifier, a stabilizer, and a fluorescent substance.

[0065] [Dry film] 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 has a resin layer obtained by applying the curable composition of the present invention onto a carrier film and drying it. When forming a dry film, the curable composition of the present invention is first diluted with the organic solvent to adjust the viscosity to an appropriate level, and then coated onto a carrier film to a uniform thickness using a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, or the like. The coated composition is then typically dried at a temperature of 40 to 130°C for 1 to 30 minutes to form a resin layer. There are no particular limitations on the thickness of the coated film, but it is generally selected appropriately from a range of 3 to 150 μm, preferably 5 to 60 μm, in terms of the film thickness after drying.

[0066] The carrier film may be a plastic film, such as a polyester film such as polyethylene terephthalate (PET), a polyimide film, a polyamideimide film, a polypropylene film, or a polystyrene film. There are no particular restrictions on the thickness of the carrier film, but it is generally selected appropriately in the range of 10 to 150 μm, and more preferably in the range of 15 to 130 μm.

[0067] After forming a resin layer made of the curable composition of the present invention on a carrier film, it is preferable to further laminate a peelable cover film on the surface of the resin layer for the purpose of preventing dust from adhering to the surface of the resin layer. As the peelable cover film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, surface-treated paper, etc. can be used. The cover film may be any film as long as the adhesive strength between the resin layer and the carrier film is smaller when the cover film is peeled off.

[0068] In the present invention, the curable composition of the present invention may be applied to the cover film and dried to form a resin layer, and then a carrier film may be laminated on the surface of the resin layer. That is, in the present invention, when producing a dry film, either a carrier film or a cover film may be used as the film to which the curable composition of the present invention is applied.

[0069] [Cured product] To form a cured product using the curable composition of the present invention, the composition is applied to a substrate, the solvent is evaporated, and the resulting resin layer is then exposed (irradiated with light) to cure the exposed areas. Specifically, a resist pattern is formed by selectively exposing the composition to active energy rays through a patterned photomask using a contact or non-contact method, or by directly exposing the pattern using a laser direct exposure device, and developing the unexposed areas with an alkaline aqueous solution (e.g., a 0.3 to 3 wt% sodium carbonate aqueous solution). Further heat curing (post-cure) by heating to a temperature of approximately 100 to 180°C results in the formation of a cured film (cured product) with excellent properties such as heat resistance, chemical resistance, moisture absorption resistance, adhesion, and electrical properties.

[0070] The curable composition of the present invention can be adjusted to a viscosity suitable for the coating method using the organic solvent, and applied to a substrate by a method such as dip coating, flow coating, roll coating, bar coating, screen printing, or curtain coating, followed by volatilization and drying (pre-drying) of the organic solvent contained in the composition at a temperature of about 60 to 100° C. to form a tack-free resin layer. Furthermore, in the case of a dry film obtained by coating the curable composition on a carrier film or cover film, drying, and winding it up as a film, the dry film of the present invention can be attached to the substrate using a laminator or the like so that the resin layer of the dry film contacts the substrate, and then peeling off the carrier film, thereby laminating the resin layer on the substrate.

[0071] Substrates include printed wiring boards and flexible printed wiring boards with circuits already formed using copper or other materials, as well as copper-clad laminates for high-frequency circuits made from materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, fluororesin, polyethylene, polyphenylene ether, polyphenylene oxide, cyanate, etc., including copper-clad laminates of all grades (FR-4, etc.), as well as metal substrates, polyimide film, PET film, polyethylene naphthalate (PEN) film, glass substrates, ceramic substrates, and wafer plates.

[0072] The volatilization drying or thermal curing can be carried out using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, etc. (a method in which hot air in the dryer is brought into countercurrent contact using a heat source of an air heating method using steam, or a method in which hot air is blown onto the support from a nozzle).

[0073] The exposure device used for the active energy ray irradiation may be a device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, or the like, and capable of irradiating active energy rays in the range of 350 to 450 nm. Furthermore, a direct imaging device (for example, a laser direct imaging device that directly draws an image with a laser based on CAD data from a computer) may also be used. The lamp or laser light source of the direct imaging device may have a maximum wavelength in the range of 350 to 410 nm. The exposure dose for image formation varies depending on factors such as the film thickness, but is generally 20 to 1,000 mJ / cm. 2 , preferably 20 to 800 mJ / cm 2 The range may be:

[0074] The developing method may be a dipping method, a shower method, a spray method, a brush method, or the like, and the developing solution may be an aqueous alkali solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, or an amine.

[0075] The curable composition of the present invention is suitably used for forming a surface protective film such as a solder resist on a flexible printed wiring board. The curable composition of the present invention may also be used as an interlayer insulating layer in a multilayer printed wiring board.

[0076] [Electronic Components] The present invention also provides an electronic component having 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 can be provided. In the present invention, electronic components refer to components used in electronic circuits, and include 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 present invention exerts the effects of the present invention as an insulating cured coating film for these components.

[0077] The fluxes to which the cured product of the present invention exhibits good resistance include all fluxes with conventional structures and formulations that are primarily based on rosin. Some examples of such fluxes include SF-270, SF-360 PF-1, SRM-800G (all manufactured by Sanwa Chemical Co., Ltd.), JS-E-15X, JS-EU-31 (all manufactured by Kokisha), NS-F850-8, NS-F901, NS-334, and NS-316F-8 (manufactured by Nippon Superior Co., Ltd.).

[0078] Hereinafter, one embodiment of the present invention will be specifically illustrated by way of an example, but it goes without saying that the purpose is not to limit the scope of the invention according to the claims of this application. [Example]

[0079] <Synthesis Example 1: Preparation of Carboxyl Group-Containing Acrylate Resin (Bisphenol A Structure)> A flask equipped with a condenser and a stirrer was charged with 456 parts of bisphenol A, 228 parts of water, and 649 parts of 37% formalin. While maintaining the temperature below 40°C, 228 parts of 25% aqueous sodium hydroxide was added. After the addition was completed, the mixture was reacted at 50°C for 10 hours. After the reaction was completed, the mixture was cooled to 40°C and neutralized to pH 4 with 37.5% aqueous phosphoric acid while maintaining the temperature below 40°C. The mixture was then allowed to stand and the aqueous layer was separated. After separation, 300 parts of methyl isobutyl ketone was added and dissolved uniformly. The mixture was then washed three times with 500 parts of distilled water, and the water, solvent, etc. were 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. A part of the obtained methanol solution of the polymethylol compound was dried at room temperature in a vacuum dryer, and the solid content was found to be 55.2%.

[0080] 500 parts of the resulting methanol solution of polymethylol compound and 440 parts of 2,6-xylenol were placed in a flask equipped with a condenser and a stirrer and dissolved uniformly at 50°C. After uniform dissolution, the methanol was removed under reduced pressure at a temperature of 50°C or below. 8 parts of oxalic acid was then added, and the mixture was reacted at 100°C for 10 hours. After the reaction was completed, the distillate was removed under reduced pressure at 180°C and 50 mmHg, yielding 550 parts of novolak resin A. An autoclave equipped with a thermometer, a nitrogen inlet / alkylene oxide inlet, and a stirrer was charged with 130 parts of novolak resin A, 2.6 parts of a 50% aqueous solution of sodium hydroxide, and 100 parts of toluene / methyl isobutyl ketone (mass ratio = 2 / 1). The system was purged with nitrogen while stirring, and then heated to 150°C and 8 kg / cm 2 60 parts of propylene oxide was gradually introduced and the reaction was carried out at a gauge pressure of 0.0 kg / cm. 2 The reaction was continued for about 4 hours until the reaction mixture reached a final concentration, after which it was cooled to room temperature. 3.3 parts of a 36% aqueous solution of hydrochloric acid was added to and mixed with the reaction solution to neutralize the sodium hydroxide. The neutralized reaction product was diluted with toluene, washed with water three times, and the solvent was removed using an evaporator to obtain a propylene oxide adduct of novolak resin A with a hydroxyl value of 189 g / eq. This product had an average of 1 mole of propylene oxide added per equivalent of phenolic hydroxyl group.

[0081] 189 parts of the resulting propylene oxide adduct of novolak resin A, 36 parts of acrylic acid, 3.0 parts of p-toluenesulfonic acid, 0.1 parts of hydroquinone monomethyl ether, and 140 parts of toluene were charged into a reactor equipped with a stirrer, thermometer, and air inlet tube, and the mixture was stirred while blowing in air. The temperature was raised to 115°C, and the reaction was continued for another 4 hours while distilling off the water produced by the reaction as an azeotrope with toluene. The mixture was then cooled to room temperature. The resulting reaction solution was washed with 5% aqueous NaCl solution, and the toluene was removed by distillation under reduced pressure. Diethylene glycol monoethyl ether acetate was then added to obtain an acrylate resin solution with a solids content of 67%.

[0082] Next, 322 parts of the obtained acrylate resin solution, 0.1 parts of hydroquinone monomethyl ether, and 0.3 parts of triphenylphosphine were charged into a four-neck flask equipped with a stirrer and a reflux condenser, and 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 photosensitive carboxyl group-containing resin solution thus obtained had a solids content of 70% and an acid value of 81 mgKOH / g.

[0083] <Synthesis Example 2: Preparation of a Carboxyl Group-Containing Resin for Comparative Example> A 2-L 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-butylperoxy 2-ethylhexanoate (Perbutyl O, manufactured by Nippon Oil & Fats Co., Ltd.) as a polymerization initiator and heated to 90°C. After heating, 309.9 g of methacrylic acid, 116.4 g of methyl methacrylate, and 109.8 g of lactone-modified 2-hydroxyethyl methacrylate (Placcel FM1, manufactured by Daicel Chemical Industries, Ltd.) were added dropwise over 3 hours along with 21.4 g of the polymerization initiator bis(4-t-butylcyclohexyl)peroxydicarbonate (Perloyl TCP, manufactured by Nippon Oil & Fats Co., Ltd.). The mixture was then aged for an additional 6 hours to obtain a carboxyl group-containing copolymer resin. The reaction was carried out under a nitrogen atmosphere. Next, 363.9 g of 3,4-epoxycyclohexylmethyl acrylate (Cyclomer A200, manufactured by Daicel Chemical Industries, 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, and the mixture was heated to 100°C and stirred to carry out the ring-opening addition reaction of the epoxy. After 16 hours, a solution containing 53.8 wt% (non-volatile content) of a carboxyl group-containing resin without aromatic rings was obtained, with an acid value of 108.9 mg KOH / g and a weight-average molecular weight of 25,000.

[0084] <Examples 1 to 7 and Comparative Examples 1 and 2> The components and amounts shown in Table 1 below were premixed in a stirrer and then kneaded in a three-roll mill to obtain curable compositions of Examples 1 to 7 and Comparative Examples 1 and 2. The numerical values of the blend amounts in the tables indicate parts by mass of solid content unless otherwise specified.

[0085] [Table 1] *1 Bisphenol 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. *2 Composite acid-modified epoxy acrylate resin, alkali-soluble resin with urethane structure (solid content 52%); UXE-3000; manufactured by Nippon Kayaku Co., Ltd. *3 Synthesis Example 1, alkali-soluble resin having a bisphenol A structure *4 Alkali-soluble resin other than (A) alkali-soluble resin in Synthesis Example 2 above *5 CAP504-0.2; Eastman Chemical Co. *6 Dicyandiamide (Dicyandiamide, "DICY") manufactured by Mitsubishi Chemical Corporation *7 Paliogen Red K3580; BASF Japan *8 Firstgen Blue 5380; manufactured by DIC Corporation *9 Plast Yellow 8025; Arimoto Chemical Industry Co., Ltd. *10 Black CK-T / SD-TT2259; manufactured by Resino Color Kogyo Co., Ltd. *11 BYK-180; manufactured by BYK Japan Co., Ltd. *12 Silicon KS-66; manufactured by Shin-Etsu Silicone Co., Ltd. *13 JMT-784; manufactured by DKSH Japan *14 Omirad379; manufactured by IGM Resins *15 Exolit® OP935; Clariant *16 Erogel #R974; manufactured by Toshin Kasei Co., Ltd. *17 Melamine; Nissan Chemical Co., Ltd. *18 UCN-5050D Clear; manufactured by Dainichi Seika Color & Chemicals Mfg. Co., Ltd. *19 Dowanol DPM; manufactured by The Dow Chemical Company *20 Epolead PB3600; manufactured by Daicel Corporation *21 NK Ester APG-700; manufactured by Shin-Nakamura Chemical Co., Ltd. *22 BPE-900; Manufactured by Shin-Nakamura Chemical Industry Co., Ltd. *23 HP-7200L; manufactured by DIC *24 jER YX-4000; manufactured by Mitsubishi Chemical Corporation *25 TEPIC (registered trademark)-VL; manufactured by Nissan Chemical Industries, Ltd. *26 TEPIC (registered trademark)-HP; manufactured by Nissan Chemical Industries, Ltd.

[0086] Cured coating films (solder resists) were prepared from the curable compositions of Examples 1 to 7 and Comparative Examples 1 and 2 obtained as shown in Table 1 above, and the cured coating films were subjected to tests for flux resistance, developability, and bending property as described below.

[0087] <Test Example 1. Evaluation of Flux Resistance> The curable compositions of Examples 1 to 7 and Comparative Examples 1 and 2 were each applied to the entire surface of a 1.6 mm thick copper foil plate that had been pretreated (with 0.20 vol% sulfuric acid peroxide solution) by screen printing so that the film thickness after drying would be 20±5 μm. Subsequently, the film was dried in a hot air circulation drying oven at 80°C for 30 minutes, and then exposed to light (150 mJ / cm) in a 5 × 5 grid pattern with 1 mm spacing. 2 ), and developed for 60 seconds using an alkaline developer (30°C) of 1 wt% Na2CO3, and then thermally cured at a temperature of 150°C or higher for 60 minutes to obtain cured coating films of Examples 1 to 7 and Comparative Examples 1 and 2, respectively. Next, flux (SF-270 manufactured by Sanwa Chemical Co., Ltd.) was applied to the entire surface of each cured coating film, a dummy wafer was placed on top, and the film was heat-treated once for 5 minutes at a speed of 1.5 m / min in a 230°C air conveyor-type heating furnace. After that, the film was peeled off using cellophane tape with a strength of 1.18 N / cm or more as specified in JIS Z 1522:2009, and the degree of peeling of the cured coating film was evaluated. The evaluation was as follows. Peeling area after peel test is 10% or less ◎ After peel test, peeling area is over 10% - 50% or less ○ After peel test, peeling area is over 50% - 100% ×

[0088] <Test Example 2. Developability> The curable compositions of Examples 1 to 7 and Comparative Examples 1 to 2 were each applied to the entire surface of a 1.6 mm thick copper foil plate that had been pretreated (0.20 vol% sulfuric acid peroxide solution) by screen printing to a film thickness of 20±5 μm after drying. The composition was then dried in a hot air circulating drying oven at 80°C for 30 minutes to obtain dried coatings of Examples 1 to 7 and Comparative Examples 1 to 2. The dried coatings were then developed using a spray of 1 wt% Na2CO3 solution (at 30°C) at a pressure of 0.1 MPa, and the development time (dissolution time) was measured to evaluate the developability. The evaluation results are as follows: Development time: Less than 20 seconds ◎ Development time: 20 seconds or more but less than 25 seconds Development time: 25 seconds or more ×

[0089] <Test Example 3. Bendability> The curable compositions of Examples 1 to 7 and Comparative Examples 1 and 2 were each applied to the entire surface of a 25 μm thick polyimide film by screen printing so that the film thickness after drying would be 20±5 μm. Subsequently, the film was dried in a hot air circulation drying oven at 80°C for 30 minutes, and then exposed to light (150 mJ / cm 2 ), and developed for 60 seconds using an alkaline developer (30°C) of 1 wt% Na2CO3, and then thermally cured at a temperature of 150°C or higher for 60 minutes to obtain cured coating films of Examples 1 to 7 and Comparative Examples 1 and 2, respectively. Next, the sample was bent 180°, and a 500 g weight was applied for 10 seconds, and the number of times it was bent until cracks appeared on the surface of the cured coating film was counted. Bend more than 5 times ◎ Bending more than twice ○ Fold less than twice ×

[0090] The test results for Test Examples 1 to 3 are shown in Table 2 below.

[0091] [Table 2]

Claims

1. (A) an alkali-soluble resin having at least one structure selected from the group consisting of a bisphenol A structure, a bisphenol F structure, and a urethane structure; (B) a photopolymerization initiator; (C) an epoxy resin having an isocyanurate structure; A curable composition comprising: the (C) epoxy resin 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 two or more carbon atoms, the amount of the (A) alkali-soluble resin is 15 to 35 mass% of the total composition, the amount of the (B) photopolymerization initiator is 8 to 15 mass parts per 100 parts by mass of the (A) alkali-soluble resin, and the amount of the (C) epoxy resin having an isocyanurate structure is 5 to 15 mass parts per 100 parts by mass of the (A) alkali-soluble resin; The curable composition.

2. The curable composition according to claim 1 , further comprising a powder or 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.

4. The curable composition according to claim 2 or 3, further comprising an epoxy resin having a dicyclopentadiene structure.

5. 5. The curable composition according to claim 4, wherein a mass ratio of the epoxy resin having an isocyanurate structure (C), the powdery or crystalline epoxy resin, and the epoxy resin having a dicyclopentadiene structure is 1:2 to 6:1 to 3.

6. The curable composition according to any one of claims 1 to 5, further comprising urethane beads and / or epoxidized polybutadiene.

7. The curable composition according to any one of claims 1 to 6, further comprising a cellulose resin.

8. A dry film having a resin layer obtained from the curable composition according to any one of claims 1 to 7.

9. A cured product obtained by curing the resin layer of the curable composition according to any one of claims 1 to 7 or the dry film according to claim 8.

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

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