Alkaline developable resin composition, dry film, cured product, and electronic component having cured product

Abstract

The invention provides an alkaline developing resin composition which is low in volatility and excellent in dispersibility, photosensitivity, developing performance and the like, a cured product of the alkaline developing resin composition is excellent in pencil hardness and heat resistance, and a coating film formed by the alkaline developing resin composition has good finger touch dryness. The alkaline developing type resin composition comprises (A) epoxy resin, (B) carboxyl-containing vinyl ester resin, (C) photopolymerization initiator, (D) photosensitive monomer, (E) inorganic filler, (F) high-boiling-point solvent and (G) reactive diluent, the (G) reactive diluent comprises at least one selected from the group consisting of (G-1) reactive diluents having a viscosity of 2-15 mPa * s (inclusive) and (G-2) reactive diluents having a viscosity of more than 15 mPa * s and 50 mPa * s (inclusive); the reactive diluent (G-1) having a viscosity of 2-15 mPa.s inclusive and the reactive diluent (G-2) having a viscosity of more than 15 mPa.s inclusive and 50 mPa.s inclusive are epoxy compounds having only one epoxy group in one molecule.

Description

Alkaline-developable resin composition, dry film, cured product, and electronic component having the cured product Technical Field

[0001] The present invention relates to an alkaline-developable resin composition, a dry film, a cured product, and an electronic component having the cured product. In particular, the present invention relates to a low-volatility alkaline-developable resin composition, a cured product thereof suitable for printed circuit boards, such as a solder mask layer, and an electronic component having the cured product. Background Art

[0002] Curable resin compositions are commonly used to form permanent coatings such as solder masks in printed circuit board manufacturing. Dry film-type compositions and liquid compositions have been developed for these curable resin compositions. Furthermore, to enable miniaturization of electronic components, high-precision design structures, and complex manufacturing methods, curable resin compositions are also expected to be capable of patterning using the principles of photography (photolithography), thereby enabling microfabrication. In recent years, alkaline-developable resins that can be developed in dilute weak alkaline aqueous solutions have become mainstream due to environmental concerns.

[0003] Traditionally, a curable resin composition (also known as solder resist or solder resist ink) has been used to form a solder mask layer on printed circuit boards (PCBs) as a protective material for the circuitry. Conventional solder resists use highly volatile, low-boiling-point solvents, which can lead to defects such as bubbles and pinholes during application. Furthermore, their high volatility also increases environmental impact.

[0004] With increasing environmental protection requirements, standards and regulations aimed at reducing volatile organic compounds (VOCs) are becoming increasingly stringent for printed circuit boards (PCBs), which use a large number of chemicals during their manufacturing process. Volatile organic compounds are defined as any organic compound with an initial boiling point of 250°C or less at a standard pressure of 101.3 kPa (see GB / T 38608-2020). VOCs are generally classified into eight categories: alkanes, aromatic hydrocarbons, olefins, halogenated hydrocarbons, esters, aldehydes, ketones, and other compounds. Common VOCs include benzene, toluene, xylene, styrene, trichloroethylene, chloroform, trichloroethane, diisocyanates, and diisocyanatomethylbenzene.

[0005] Patent Document 1 uses water to replace high-boiling-point solvents to reduce VOC emissions. However, its solder mask ink has disadvantages such as poor storage stability (the carboxyl groups of the acrylic resin in the ink that can participate in the development reaction are wrapped by water molecules after being hydrophilic. The water molecule wrapping weakens the acid-base reaction between the carboxyl groups and the sodium carbonate developer, thereby reducing the ink's developability. In severe cases, the development is not clean), and the use process is complicated. In addition, the ink has insufficient characteristics and a limited range of applications. Patent Document 2 uses environmentally friendly solvents (such as one or more of ethylene glycol butyl ether (boiling point 171°C), divalent acid esters (boiling point 196-225°C), diethylene glycol monobutyl ether (boiling point 230.5°C), ethylene glycol acetate (boiling point 83°C), and propylene glycol methyl ether (boiling point 120°C)), but the VOC content is greater than 20%.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: CN 108219585A

[0009] Patent Document 2: CN 113604103A Summary of the Invention

[0010] Problems to be solved by the invention

[0011] Conventional developing solder resist compositions have traditionally used aromatic solvents (such as the heavy aromatic solvent naphtha S-150) and low-boiling-point ester or ether solvents (such as dipropylene glycol monomethyl ether and diethylene glycol ethyl ether acetate). Their primary drawback is that they contain volatile organic compounds (VOCs) exceeding 20%, posing a significant environmental hazard. Furthermore, due to the rapid evaporation of these solvents, they can easily generate bubbles when printing on thick copper plates (e.g., copper thicknesses of 2 oz (70 μm) or greater), or when printing thick films, resulting in poor appearance of the cured film. Furthermore, solder resist compositions, as protective materials, are required to possess excellent ink properties such as dispersibility, photosensitivity, and developability. Their cured products are also required to exhibit excellent pencil hardness and heat resistance to withstand the high heat of solder attachment. Furthermore, the coating is required to exhibit good dry-to-touch properties, ensuring that the cured film (e.g., solder resist layer) has a good appearance.

[0012] Therefore, it is desirable to produce an alkaline-developable resin composition with low volatility (VOCs detection value below 10%) while maintaining excellent ink performance. Furthermore, the cured product thereof exhibits excellent pencil hardness and further improved heat resistance, and the resulting coating film exhibits excellent dry-to-touch properties.

[0013] From the perspective of ink performance, it is desirable to obtain an alkaline-developable resin composition with low volatility, good dispersibility, photosensitivity, and developability (i.e., the ink performance in the present invention primarily refers to the composition's VOC content, dispersibility, photosensitivity, and developability). Furthermore, if the resulting coating film has excellent dry-to-touch properties, the cured film surface will exhibit no film marks upon exposure. Conversely, if the dry-to-touch properties are poor, the coating surface will be highly tackier, and film marks will readily form upon exposure. After curing, the cured film surface will also be more susceptible to marks, resulting in a poor appearance.

[0014] Therefore, an object of the present invention is to provide an alkali-developable resin composition having low volatility and excellent dispersibility, photosensitivity, and developability, wherein the cured product thereof has excellent pencil hardness and heat resistance and the coating film thereof has excellent dryness to touch.

[0015] A further object of the present invention is to provide a dry film and cured product having excellent properties as described above, obtained by using such an alkaline-developable resin composition, and an electronic component such as a printed wiring board having a cured coating such as a solder resist formed from the dry film or cured product.

[0016] Solutions for solving problems

[0017] The present inventors have conducted intensive research and have found that the above-mentioned problems can be solved by the following alkaline-developable resin composition. The alkaline-developable resin composition is composed of at least a two-component resin composition, characterized in that the alkaline-developable resin composition contains: (A) an epoxy resin, (B) a carboxyl group-containing vinyl ester resin, (C) a photopolymerization initiator, (D) a photosensitive monomer, (E) an inorganic filler, (F) a high-boiling-point solvent, and (G) a reactive diluent.

[0018] The boiling point of the high boiling point solvent (F) is higher than 250°C and lower than 280°C,

[0019] The reactive diluent (G) comprises at least one selected from the group consisting of (G-1) a reactive diluent having a viscosity of 2 mPa·s to 15 mPa·s and (G-2) a reactive diluent having a viscosity of greater than 15 mPa·s to 50 mPa·s, wherein the reactive diluent (G-1) having a viscosity of 2 mPa·s to 15 mPa·s and (G-2) having a viscosity of greater than 15 mPa·s to 50 mPa·s are epoxy compounds having only one epoxy group per molecule.

[0020] The present invention is completed by the following steps: the content of the reactive diluent (G-1) having a viscosity of 2 mPa·s to 15 mPa·s is greater than 5 parts by mass and less than 25 parts by mass, and the content of the reactive diluent (G-2) having a viscosity of greater than 15 mPa·s to 50 mPa·s is greater than 5 parts by mass and less than 30 parts by mass, relative to 100 parts by mass of the (B) carboxyl group-containing vinyl ester resin in terms of solid content.

[0021] Among them, a preferred embodiment of the present invention relates to an alkaline-developable resin composition, characterized in that the reactive diluent (G-1) having a viscosity of greater than 2 mPa·s and less than 15 mPa·s is the epoxy compound having an unsaturated group, and the reactive diluent (G-2) having a viscosity greater than 15 mPa·s and less than 50 mPa·s is the epoxy compound having an aromatic ring.

[0022] Furthermore, a preferred embodiment of the present invention relates to an alkali-developable resin composition, characterized in that, in the at least two-component system, each component may optionally contain a solvent other than the (G) reactive diluent.

[0023] A further preferred embodiment of the present invention relates to an alkaline-developable resin composition, characterized in that, in the at least two-component system, the component containing the (G) reactive diluent does not contain any solvent other than the (G) reactive diluent.

[0024] A further preferred embodiment of the present invention relates to an alkaline-developable resin composition, characterized in that the reactive diluent (G-1) having a viscosity of 2 mPa·s or more and 15 mPa·s or less is at least one selected from 3,4-epoxycyclohexylmethyl (meth)acrylate and glycidyl (meth)acrylate, and the reactive diluent (G-2) having a viscosity of greater than 15 mPa·s and less than 50 mPa·s is p-tert-butylphenyl glycidyl ether.

[0025] A further preferred embodiment of the present invention relates to an alkaline-developable resin composition, characterized in that the content of volatile organic compounds is 10% by mass or less.

[0026] Moreover, another aspect of the present invention relates to a dry film obtained by applying the above-mentioned alkali-developable resin composition on a carrier film and drying the resultant.

[0027] Moreover, another aspect of the present invention relates to a cured product obtained by curing the above-mentioned alkali-developable resin composition.

[0028] Furthermore, another embodiment of the present invention preferably relates to a cured product characterized in that it is obtained by curing the resin layer of the dry film.

[0029] Another aspect of the present invention relates to an electronic component including the cured product.

[0030] Effects of the Invention

[0031] The present invention provides an alkali-developable resin composition having low volatility, excellent dispersibility, photosensitivity, and developability, and also having excellent pencil hardness and heat resistance of the formed cured product and excellent dry-to-touch properties of the formed coating film.

[0032] Furthermore, the present invention can provide a dry film and cured product having excellent properties as described above obtained by using such an alkaline-developable resin composition, and an electronic component such as a printed wiring board in which a cured film such as a solder resist is formed from the dry film or cured product. DETAILED DESCRIPTION

[0033] The alkaline-developable resin composition of the present invention is preferably composed of at least a two-component resin composition. For example, a two-component system can be employed, wherein one resin composition serves as a main component (main component composition) and another resin composition serves as a curing agent component (curing agent composition). In this case, for example, the main component preferably comprises at least (B) a carboxyl group-containing vinyl ester resin, (C) a photopolymerization initiator, (E) an inorganic filler, and (F) a high-boiling-point solvent, and the curing agent preferably comprises at least (A) an epoxy resin, (D) a photosensitive monomer, and (G) a reactive diluent.

[0034] Here, from the viewpoint of preventing chemical reactions during storage, it is preferred that (A) the epoxy resin and (B) the carboxyl group-containing vinyl ester resin are directly contained in separate compositions, (D) the photosensitive monomer and (C) the photopolymerization initiator are directly contained in separate compositions, and the component containing the (G) reactive diluent does not contain any solvent other than the (G) reactive diluent.

[0035] Furthermore, if (B) the carboxyl vinyl ester resin and (C) the photopolymerization initiator are contained in the same composition, the detailed mechanism is unclear, but the cured film of the composition may suffer from poor appearance and coarse particles. However, the present inventors have discovered that by using a base composition comprising at least (B) the carboxyl vinyl ester resin, (C) the photopolymerization initiator, and (F) a high-boiling-point solvent in a specific boiling point range, and a curing agent composition comprising at least (A) the epoxy resin, (D) the photosensitive monomer, and (G) the reactive diluent, this problem can be alleviated while reducing the VOC content.

[0036] Hereinafter, each component constituting the alkali-developable resin composition of the present invention will be described.

[0037] (A) Epoxy resin

[0038] (A) The epoxy resin functions as a thermosetting component in the alkaline-developable resin composition to form a cured product.

[0039] As such an epoxy resin (A), a well-known and commonly used multifunctional epoxy resin having at least two epoxy groups in one molecule can be used.

[0040] (A) The epoxy resin may be in a liquid state, a solid state, or even a semi-solid state.

[0041] As the multifunctional epoxy resin, preferably bisphenol A type epoxy resin; brominated epoxy resin; novolac type epoxy resin; bisphenol F type epoxy resin; hydrogenated bisphenol A type epoxy resin; glycidylamine type epoxy resin; hydantoin type epoxy resin; alicyclic epoxy resin; trishydroxyphenylmethane type epoxy resin; bixylenol type or biphenol type epoxy resin or a mixture thereof; bisphenol S type epoxy resin; bisphenol A novolac type epoxy resin; tetrahydroxyphenylethane type epoxy resin; Resin; heterocyclic epoxy resin; diglycidyl phthalate resin; tetraglycidyl ditoluoyl ethane resin; naphthyl-containing epoxy resin; epoxy resin having a dicyclopentadiene skeleton; glycidyl methacrylate copolymer epoxy resin; copolymerized epoxy resin of cyclohexylmaleimide and glycidyl methacrylate; epoxy-modified polybutadiene rubber derivative; CTBN-modified epoxy resin, epoxy resin having an isocyanurate ring, etc., but of course not limited to these.

[0042] These epoxy resins can be used alone or in combination of two or more.

[0043] As the "epoxy resin that is solid or semi-solid at room temperature" in the component (A), a known and commonly used one can be used. For example, examples of epoxy resins that are solid at room temperature include bisphenol A epoxy resins (jER1001 manufactured by Mitsubishi Chemical Corporation, 128E manufactured by Nan Ya Plastics Co., Ltd.), bisphenol F epoxy resins (jER4004P manufactured by Mitsubishi Chemical Corporation), naphthalene epoxy resins (HP-4700 manufactured by DIC Corporation), polyfunctional solid epoxy resins containing a naphthalene skeleton (NC-7000 manufactured by Nippon Kayaku Co., Ltd.), naphthyl group-containing epoxy resins (ESN-190, ESN-360 manufactured by Nippon Steel Chemical & Material Co., Ltd., HP-4032, EXA-4750, EXA-4700 manufactured by DIC Corporation), trisphenol epoxy resins (EPPN-502H manufactured by Nippon Kayaku Co., Ltd.), polyfunctional solid epoxy resins containing a dicyclopentadiene skeleton (Epiclon manufactured by DIC Corporation), and epoxy resins containing naphthalene groups. HP-7200, HP-7200H), phosphorus-containing epoxy resin (TX0712 manufactured by Nippon Steel & Sumikin Chemicals Corporation), tris(2,3-epoxypropyl)isocyanurate (TEPIC manufactured by Nissan Chemical Industries, Ltd.), as epoxy resins that are semi-solid at room temperature, bisphenol A type epoxy resin (jER834 manufactured by Mitsubishi Chemical Corporation), naphthalene type epoxy resin (HP-4032 manufactured by DIC Corporation), etc.

[0044] Here, in the present invention, being solid or semi-solid at room temperature means being solid or semi-solid at 15° C. Determination of solid or semi-solid can be made in accordance with Annex 2, "Method for Confirming Liquid State," of the Ministerial Ordinance concerning the Test and Properties of Dangerous Substances (Ministry of Home Affairs Ordinance No. 1 of 1991).

[0045] As the biphenyl-type epoxy resin in component (A), a well-known and commonly used multifunctional epoxy resin having a biphenyl skeleton can be used. Examples thereof include multifunctional solid epoxy resins containing a biphenyl skeleton (NC-3000H and NC-3000 manufactured by Nippon Kayaku Co., Ltd.) and biphenyl-type epoxy resins (YX-4000 and YL-6121HA manufactured by Mitsubishi Chemical Corporation).

[0046] Examples of the novolac-type epoxy resin in component (A) include cresol novolac-type epoxy resin (Epiclon N-690 manufactured by DIC Corporation), phenol / modified novolac-type epoxy resin (Epiclon N-770 manufactured by DIC Corporation, jER152 manufactured by Mitsubishi Chemical Corporation), and bisphenol A novolac-type epoxy resin (BNE200 manufactured by Tiantai High-tech (Guangzhou) Co., Ltd.).

[0047] As the epoxy resin having an isocyanurate ring in the component (A), triglycidyl isocyanurate epoxy resin (TGIC-G manufactured by Shanghai Xindi Chemical Co., Ltd.) and the like can be mentioned.

[0048] The content of the epoxy resin (A) described above is preferably 30 parts by mass to 90 parts by mass, more preferably 40 parts by mass to 80 parts by mass, relative to 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) in terms of solid content.

[0049] (B) Carboxyl vinyl ester resin

[0050] The carboxyl group-containing vinyl ester resin (B) used in the present invention is preferably one having an ethylenically unsaturated double bond in the molecule from the perspectives of alkali developability, photocurability, and development resistance. Furthermore, it is more preferred that the unsaturated double bond be derived from acrylic acid, methacrylic acid, or a derivative thereof. Specific examples of the carboxyl group-containing vinyl ester resin (B) are shown below.

[0051] (1) Carboxyl group-containing vinyl ester resins obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with one or more other compounds having unsaturated double bonds;

[0052] (2) Carboxyl group-containing vinyl ester resins obtained by adding an ethylenically unsaturated group as a pendant group to a copolymer of an unsaturated carboxylic acid such as (meth)acrylic acid and one or more other compounds having an unsaturated double bond, using a compound having an epoxy group and an unsaturated double bond, such as glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, or (meth)acryloyl chloride;

[0053] (3) Carboxyl group-containing vinyl ester resins obtained by reacting a copolymer of a compound having an epoxy group and an unsaturated double bond, such as glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate, and another compound having an unsaturated double bond, with an unsaturated carboxylic acid, such as (meth)acrylic acid, and reacting a polybasic acid anhydride with the resulting secondary hydroxyl group;

[0054] (4) Carboxyl group-containing vinyl ester resins obtained by reacting a copolymer of an acid anhydride having an unsaturated double bond, such as maleic anhydride, and another compound having an unsaturated double bond, with a compound having a hydroxyl group and an unsaturated double bond, such as 2-hydroxyethyl (meth)acrylate;

[0055] (5) Carboxyl group-containing vinyl ester resins obtained by reacting a polyfunctional epoxy compound with an unsaturated monocarboxylic acid and reacting a saturated or unsaturated polybasic acid anhydride with the resulting hydroxyl group;

[0056] (6) A vinyl ester resin containing hydroxyl groups and carboxyl groups obtained by reacting a hydroxyl-containing polymer such as a polyvinyl alcohol derivative with a saturated or unsaturated polybasic acid anhydride, and then reacting a compound having an epoxy group and an unsaturated double bond in one molecule with the resulting carboxylic acid;

[0057] (7) a carboxyl group-containing vinyl ester resin obtained by reacting a reaction product of a polyfunctional epoxy compound and an unsaturated monocarboxylic acid with a compound having at least one alcoholic hydroxyl group and one reactive group other than the alcoholic hydroxyl group that reacts with an epoxy group in one molecule, with a saturated or unsaturated polybasic acid anhydride;

[0058] (8) a carboxyl group-containing vinyl ester resin obtained by reacting an unsaturated monocarboxylic acid with a polyfunctional oxetane compound having at least two oxetane rings in one molecule, and reacting a saturated or unsaturated polybasic acid anhydride with the primary hydroxyl group in the resulting modified oxetane resin; and

[0059] (9) Carboxyl group-containing vinyl ester resins obtained by reacting a bifunctional epoxy compound with an unsaturated monocarboxylic acid and reacting a saturated or unsaturated polybasic acid anhydride with the generated hydroxyl group.

[0060] (10) Carboxyl group-containing vinyl ester resins obtained by reacting a polyfunctional epoxy resin such as a phenol novolac epoxy resin, a cresol novolac epoxy resin, a bisphenol A cresol novolac epoxy resin, or a dicyclopentadiene cresol novolac 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;

[0061] (11) reacting the multifunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of the multifunctional epoxy resin in the above-mentioned (10) with epichlorohydrin with (meth)acrylic acid, and adding a polybasic acid anhydride to the generated hydroxyl groups to obtain a carboxyl group-containing vinyl ester resin;

[0062] (12) Carboxyl group-containing vinyl ester resins obtained by adding cyclic ethers such as ethylene oxide or cyclic carbonates such as propylene carbonate to polyfunctional phenolic compounds such as novolac resins, partially esterifying the resulting hydroxyl groups with (meth)acrylic acid, and reacting the remaining hydroxyl groups with a polyacid anhydride;

[0063] (13) Carboxyl vinyl ester resins obtained by further adding a compound having one epoxy group and one or more (meth)acryloyl groups in the molecule, such as glycidyl (meth)acrylate or monomethylglycidyl (meth)acrylate, to any of the resins described above (10) to (12);

[0064] Particularly preferred among these examples are cresol novolac type and phenol novolac type, and the carboxyl group-containing vinyl ester resins of (5), (9), (10), (11), (12), and (13) mentioned above.

[0065] It should be noted that, in this specification, (meth)acrylate is a term that collectively refers to acrylate, methacrylate, and a mixture thereof, and the same applies to other similar expressions.

[0066] Since the carboxyl group-containing vinyl ester resin (B) described above has a plurality of free carboxyl groups on the side chains of the main chain polymer, it can be developed with a dilute alkaline aqueous solution.

[0067] The acid value of the carboxyl group-containing vinyl ester resin (B) is preferably in the range of 40 to 200 mgKOH / g, more preferably in the range of 45 to 120 mgKOH / g. If the acid value of the carboxyl group-containing resin is less than 40 mgKOH / g, alkali development becomes difficult. On the other hand, if it exceeds 200 mgKOH / g, dissolution of the exposed portion by the developer is promoted, resulting in thinner lines than desired. In some cases, the exposed and unexposed portions may be dissolved and peeled off indiscriminately by the developer, making it difficult to form a normal resist pattern. This is not preferred.

[0068] The weight-average molecular weight of the carboxyl group-containing vinyl ester resin (B) varies depending on the resin backbone, but is generally preferably in the range of 2,000 to 150,000, more preferably 5,000 to 100,000. A weight-average molecular weight of less than 2,000 may result in poor application to a substrate and poor tackiness (dry to touch) after drying. Furthermore, the moisture resistance of the cured film after exposure may deteriorate, film loss may occur during development, and resolution may be significantly reduced. On the other hand, a weight-average molecular weight exceeding 150,000 may result in significantly poor developability and poor storage stability.

[0069] (C) Photopolymerization initiator

[0070] (C) Photopolymerization initiator includes, for example, 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-trimethylbenzoyl)-phenylphosphine oxide, and bisacylphosphine oxide; ,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine oxide, methyl 2,4,6-trimethylbenzoylphenylphosphine oxide, 2-methylbenzoyldiphenylphosphine oxide, isopropyl pivaloylphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide (TMO; (Di-p-tolylphosphoryl)(mesityl)methanone) and other monoacylphosphine oxides; 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]-1- benzoin, benzil, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether, and other benzoin compounds; benzoin alkyl ethers; benzophenones such as benzophenone, p-methylbenzophenone, Michler's ketone, methyl benzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bis(diethylamino)benzophenone; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholine Acetophenones such as 1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone, and N,N-dimethylaminoacetophenone; thioxanthones such as 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;Benzoate esters 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-benzoyl oxime) and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone 1-(O-acetyl oxime); bis( Titanocenes such as 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; 2-nitrofluorene phenyl disulfide, butyroin, anisoin ethyl ether, azobisisobutyronitrile, and tetramethylthiuram disulfide. Photopolymerization initiators may be used alone or in combination of two or more.

[0071] The content of the photopolymerization initiator (C) is preferably 5 parts by mass or more and 25 parts by mass or less relative to 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) in terms of solid content. When the content is 5 parts by mass or more, surface curability is improved, while when the content is 25 parts by mass or less, halation is less likely to occur, resulting in good resolution.

[0072] (D) Photosensitive monomer

[0073] The photosensitive monomer (D) is preferably a compound having one or more ethylenically unsaturated groups in its molecule. The photosensitive monomer (D) containing such an ethylenically unsaturated group contributes to the photocuring of the carboxyl vinyl ester resin (B) by irradiation with active energy rays, thereby curing the alkaline-developable resin composition.

[0074] (D) The photosensitive monomer preferably used in the present invention includes, for example, methyl α-(allyloxymethyl)acrylate, or 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 hydroxypivalate neopentyl glycol diacrylate, bisphenol A EO adduct diacrylate, bisphenol A PO adduct diacrylate, tricyclodecane dimethanol diacrylate, hydrogenated dicyclopentadienyl diacrylate, cyclohexyl diacrylate esters, or bifunctional (meth)acrylates such as methacrylate monomers corresponding thereto, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolmethane triacrylate, ethylene oxide-modified trimethylolpropane triacrylate, propylene oxide-modified trimethylolpropane triacrylate, epichlorohydrin-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, tetramethylolmethane tetraacrylate, ethylene oxide-modified phosphoric acid triacrylate, epichlorohydrin-modified glycerol triacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, or polyfunctional acrylates such as silsesquioxane-modified products thereof, or methacrylate monomers corresponding thereto, trifunctional methacrylates, polyfunctional (meth)acrylates such as ε-caprolactone-modified tris(acryloyloxyethyl)isocyanurate, or combinations of two or more thereof.

[0075] The content of the photosensitive monomer (D) is preferably 2 parts by mass to 25 parts by mass, more preferably 4 parts by mass to 20 parts by mass, relative to 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) in terms of solid content.

[0076] When the content of the photosensitive monomer (D) is within such a range, the alkali-developable resin composition has sufficient photocurability, patterning during development becomes more favorable, and dryness to touch also becomes favorable.

[0077] (E) Inorganic fillers

[0078] In the present invention, the inorganic filler (E) may be used alone or in combination of two or more. The amount of the inorganic filler (E) is preferably in the range of 35 parts by mass or more and 200 parts by mass or less, and more preferably in the range of 50 parts by mass or more and 150 parts by mass or less, relative to 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) in terms of solid content. When the amount of the inorganic filler (E) is 35 parts by mass or more, a cured film having superior soldering heat resistance, insulation reliability, and heat discoloration resistance tends to be obtained. When the amount of the inorganic filler (E) is 200 parts by mass or less, an alkaline-developable resin composition having superior degassing properties, resolution, and deep curing properties tends to be obtained.

[0079] Examples of the inorganic filler (E) include titanium oxide, silicon dioxide, barium sulfate, barium titanate, Neuburg silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, and aluminum nitride. Among these, at least one of talc, silicon dioxide, and barium sulfate is preferred from the perspectives of improving mechanical properties, heat resistance, and processability. The main agent preferably contains an inorganic filler, and barium sulfate is preferably used as the inorganic filler, as this can suppress cure shrinkage of the cured product of the alkaline-developable resin composition and improve properties such as adhesion and hardness.

[0080] (E) The inorganic filler may be surface-treated and used. More preferably, the surface of the inorganic filler is surface-treated to introduce curable reactive groups.

[0081] Here, the curable reactive group refers to a group that undergoes a curing reaction with (A) an epoxy resin or the like, or (B) a carboxyl group-containing vinyl ester resin, and may be a photocurable reactive group or a thermosetting reactive group. Examples of the photocurable reactive group include methacryloyl, acryloyl, vinyl, and styryl groups, while examples of the thermosetting reactive group include epoxy, amino, hydroxyl, carboxyl, isocyanate, imino, oxetanyl, mercapto, methoxymethyl, methoxyethyl, ethoxymethyl, ethoxyethyl, and oxazoline groups.

[0082] The method for introducing curable reactive groups into the surface of (E) the inorganic filler is not particularly limited, and can be introduced using a known conventional method. The surface of the inorganic filler can be treated with a surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group as an organic group. As coupling agents, silane coupling agents, titanium coupling agents, zirconium coupling agents, aluminum coupling agents, etc. can be used. It should be noted that, as inorganic fillers without a surface treatment of curable reactive groups, for example, silica-alumina surface treatment, titanate coupling agent treatment, aluminate coupling agent treatment, organically treated inorganic fillers, etc. can be cited.

[0083] The average particle size (D50) of the inorganic filler (E) is 2000 nm or less, more preferably 1200 nm or less. The lower limit thereof is preferably 0.1 nm or more in terms of the average particle size (D50).

[0084] (E) The smaller the average particle size of the inorganic filler, the more diffuse reflection during light irradiation is suppressed, and the micro-processing of the cured product pattern can be facilitated. The average particle size (D50) can be obtained using a laser diffraction particle size distribution measuring device and a measuring device based on a dynamic light scattering method. As a measuring device based on a laser diffraction method, MicrotracMT3300EXII manufactured by MicrotracBEL Inc. can be cited, and as a measuring device based on a dynamic light scattering method, Nanotrac Wave II UT151 manufactured by MicrotracBEL Inc. can be cited.

[0085] (F) High boiling point solvent

[0086] The alkaline-developable resin composition of the present invention achieves the above-mentioned object of the present invention by using a high-boiling-point solvent having a higher boiling point than conventional solvents in the main component.

[0087] Specifically, the inventors have discovered through intensive research that, when a low-VOC (carboxylic vinyl ester) resin (B) is directly used in an alkaline-developable resin composition to reduce the VOC content to below 20%, the composition becomes highly viscous and prone to bubbles, resulting in poor appearance of the cured film. Furthermore, if the solvent's boiling point is too high (above 280°C), it becomes difficult to volatilize, resulting in a large amount of residual solvent during pre-baking, which in turn deteriorates the film's dryness to touch.

[0088] By using a high-boiling-point solvent within a specific boiling point range, exceeding 250°C and below 280°C, the alkaline-developable resin composition reduces bubbles during printing and improves visual defects such as orange peel and pinholes in the cured film. This ensures the ink performance of the alkaline-developable resin composition while significantly reducing environmental impact due to its low volatility.

[0089] Such a high boiling point solvent may be, for example, any one or more selected from polyol ethers, polyol esters, organic acid alkyl esters (esters obtained by reacting an organic acid with a monohydric alcohol), aliphatic hydrocarbons, etc. Among them, polyol ethers and polyol esters are preferred, and polyol ethers are more preferred, from the perspective of further facilitating the achievement of the object of the present invention. These high boiling point solvents may be used alone or in combination of two or more.

[0090] Specific examples of high-boiling-point solvents include diethylene glycol dibutyl ether (boiling point 254° C.), tripropylene glycol n-butyl ether (boiling point 254° C.), tetraethylene glycol dimethyl ether (boiling point 275° C.), and tripropylene glycol dibutyl ether (boiling point 275° C.).

[0091] The content of the high boiling point solvent is 40 parts by mass or more and 80 parts by mass or less, more preferably 45 parts by mass or more and 75 parts by mass or less, and further preferably 50 parts by mass or more and 70 parts by mass or less, relative to 100 parts by mass of the carboxyl vinyl ester resin (B) in terms of solid content. If the content is too low, the ink performance is poor. If the content is too high, there may be a tendency for the dryness to touch of the coating to deteriorate. By using a high boiling point solvent within the above content range, the alkaline developing resin composition has excellent ink performance while reducing the VOCs content. Bubbles are not easy to appear when printing thick copper plates, so that the coating has good dryness to touch, thereby making its cured film have an excellent appearance.

[0092] (G) Reactive diluent

[0093] The alkaline-developable resin composition of the present invention utilizes a reactive diluent (G) having a specific viscosity and molecular structure in the curing agent component to adjust the viscosity of the composition, thereby achieving a higher thermal crosslink density after curing of the ink. Furthermore, it is presumed that since the reactive diluent (G) participates in the reaction and is bonded to the cured product, it does not contribute to the environmental burden as a volatile component. Furthermore, while improving ink properties such as dispersibility, photosensitivity, and developability of the alkaline-developable resin composition, the composition unexpectedly further improves the pencil hardness and heat resistance of its cured product, and imparts excellent set-to-touch properties to the resulting coating film, thereby achieving the aforementioned objectives of the present invention.

[0094] In the present invention, the (G) reactive diluent includes an epoxy compound having only one epoxy group in one molecule, and the viscosity of the reactive diluent is 2 mPa·s or more and 50 mPa·s or less.

[0095] Preferably, the (G) reactive diluent comprises at least one of (G-1) a reactive diluent having a viscosity of 2 mPa·s or more and 15 mPa·s or less and (G-2) a reactive diluent having a viscosity of greater than 15 mPa·s and 50 mPa·s or less, that is, only one of them may be used or the two may be used in combination.

[0096] The reactive diluent (G-1) having a viscosity of 2 mPa·s or more and 15 mPa·s or less is an epoxy compound having an unsaturated group, that is, an epoxy compound having an unsaturated group and having only one epoxy group per molecule. The present invention adds this specific low-viscosity, unsaturated epoxy reactive diluent to the curing agent component. It is speculated that due to the high reactivity of the unsaturated group, it can undergo self-polymerization and copolymerization with other monomers, thereby increasing the photocuring crosslinking density of the system. The epoxy group can react with hydroxyl, amino, carboxyl, or anhydride groups, introducing more functional groups and increasing the thermal crosslinking density of the system, thereby further improving the ink properties of the composition and the mechanical and physical strength, heat resistance, and other properties of the resulting cured product.

[0097] From the perspective of easily forming a cross-linked structure and thus improving properties such as strength, the reactive diluent (G-1) having a viscosity of 2 mPa·s or more and 15 mPa·s or less is preferably an epoxy compound having an ethylenically unsaturated group and only one epoxy group in one molecule, more preferably an epoxy compound having an ethylenically unsaturated group and only one glycidyl group in one molecule, and even more preferably a glycidyl ester of an unsaturated monobasic organic acid. For example, glycidyl acrylate, glycidyl methacrylate, glycidyl crotonate, 4-heptenoic acid glycidyl ester, glycidyl sorbate, glycidyl linoleate, 4-methyl-3-pentenoic acid glycidyl ester, glycidyl 3-cyclohexene carboxylic acid, glycidyl ester of unsaturated carboxylic acids such as glycidyl ester of 4-methyl-3-cyclohexene carboxylic acid, from the viewpoint of reactivity with groups such as carboxyl and compatibility with other components, diluting ability, preferably (meth) acrylic acid 3,4-epoxycyclohexyl methyl ester, glycidyl (meth) acrylate, more preferably glycidyl (meth) acrylate. As a commercially available commodity of glycidyl methacrylate, GMA manufactured by Sigma-Aldrich can be listed. Above-mentioned (G-1) reactive diluent can be used alone or in combination of two or more.

[0098] The reactive diluent having a viscosity (G-1) of 2 mPa·s to 15 mPa·s is preferably a reactive diluent having a viscosity (G-1') greater than 5 mPa·s to less than 12 mPa·s, and more preferably a reactive diluent having a viscosity (G-1") greater than 7 mPa·s to 10 mPa·s.

[0099] The reactive diluent (G-2) having a viscosity greater than 15 mPa·s and less than 50 mPa·s is an epoxy compound having an aromatic ring, that is, an epoxy compound having an aromatic ring and only one epoxy group per molecule. The present invention adds this specific low-viscosity, aromatic-ringed epoxy reactive diluent to the curing agent component. It is speculated that the addition of the aromatic ring improves the heat resistance of the composition, and the structure contains rigid segments, resulting in strong dilution ability and high reactivity. The epoxy group can react with hydroxyl, amino, carboxyl, or anhydride groups, introducing more functional groups and increasing the thermal bridging density of the system, thereby further improving the ink properties of the composition and the mechanical and physical strength and heat resistance of the resulting cured product.

[0100] From the perspectives of reactivity with groups such as carboxyl groups, compatibility with other components, and dilutability, the reactive diluent (G-2) having a viscosity greater than 15 mPa·s and less than 50 mPa·s is preferably a glycidyl ether having an aromatic ring, and more preferably a phenyl glycidyl ether, wherein the phenyl group may be optionally substituted with a substituent such as an alkyl group, a halogen atom, an amino group, an amine group, or a nitro group. From the perspectives of compatibility with other components and dilutability, glycidyl ethers in which the phenyl group is substituted with an alkyl group are preferred, and the alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and even more preferably an alkyl group having 1 to 6 carbon atoms. Examples of the reactive diluent (G-2) having a viscosity of greater than 15 mPa·s and less than 50 mPa·s include methylphenyl glycidyl ether, ethylphenyl glycidyl ether, propylphenyl glycidyl ether, butylphenyl glycidyl ether, pentylphenyl glycidyl ether, hexylphenyl glycidyl ether, heptylphenyl glycidyl ether, octylphenyl glycidyl ether, nonylphenyl glycidyl ether, and decylphenyl glycidyl ether. Preferred is butylphenyl glycidyl ether, and more preferred is p-tert-butylphenyl glycidyl ether. Commercially available products of p-tert-butylphenyl glycidyl ether include XY693 manufactured by Kyokase Chemical Industries, Ltd. and DENACOL EX-146 manufactured by NagasechemteX. The reactive diluent (G-2) having a viscosity of greater than 15 mPa·s and less than 50 mPa·s may be used alone or in combination of two or more.

[0101] The reactive diluent having a viscosity (G-2) greater than 15 mPa·s and less than 50 mPa·s is preferably a reactive diluent having a viscosity (G-2') greater than 15 mPa·s and less than 40 mPa·s, and more preferably a reactive diluent having a viscosity (G-2") greater than 15 mPa·s and less than 30 mPa·s.

[0102] The content of the reactive diluent (G-1) having a viscosity of 2 mPa·s to 15 mPa·s, based on 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) on a solids basis, is greater than 5 parts and less than 25 parts by mass, preferably greater than 6 parts and less than 23 parts by mass, more preferably greater than 8 parts and less than 20 parts by mass, and even more preferably greater than 10 parts and less than 18 parts by mass. The content of the reactive diluent (G-2) having a viscosity of greater than 15 mPa·s to 50 mPa·s, based on 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) on a solids basis, is greater than 5 parts and less than 30 parts by mass, preferably greater than 7 parts and less than 27 parts by mass, more preferably greater than 8 parts and less than 25 parts by mass, and even more preferably greater than 10 parts and less than 25 parts by mass. (G) If the amount of reactive diluent added is too low, the dispersibility, photosensitivity, and developability may not be significantly improved, and the heat resistance and pencil hardness of the cured product may not be further improved. It may also have an adverse effect on the touch drying property of the coating film, thereby affecting the appearance of the cured film. If the amount added is too high, the viscosity of the system is low, making it difficult to disperse, which will adversely affect the dispersibility and developability of the resin composition, the touch drying property of the coating film, and the heat resistance of the cured product.

[0103] The viscosity in this specification is measured using a cone rotation viscometer (TVE-33H manufactured by Toki Sangyo Co., Ltd.) using a cone rotor 1°34'×R24 at a rotation speed of 100 rpm, 25°C, and 30 seconds.

[0104] In the at least two-component system of the present invention, each component may optionally further include a solvent other than the reactive diluent (G), such as various conventional solvents. Preferably, the component containing the reactive diluent (G) does not contain any other solvent other than the reactive diluent (G). This reduces the VOC content while further improving the hardness and heat resistance of the cured product, as the reactive diluent (G) itself forms part of the crosslinked structure and no other solvents that could contribute to VOCs are present.

[0105] Other solvents

[0106] In the present invention, for general purposes, such as preparing the various component systems of the alkali-developable resin composition and adjusting the viscosity thereof, a solvent other than the above-mentioned high-boiling-point solvent may be used in at least one component system.

[0107] Solvents other than the high-boiling point solvents may be conventional organic solvents, examples of which 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 monoether (DPM), dipropylene glycol diethyl ether, and tripropylene glycol monomethyl ether; esters such as ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate (CA), 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 solvents such as petroleum ether, petroleum naphtha, solvent naphtha, and heavy aromatic solvent naphtha.

[0108] These conventional organic solvents can be used alone or in combination of two or more.

[0109] The curing agent composition of the alkaline-developable resin composition of the present invention preferably does not contain any solvent other than the reactive diluent (G). Of course, conventional solvents may be optionally further used in the various components of the system for general purposes in the art. When a conventional solvent is used, for example, the content of the conventional solvent is preferably in the range of 2 parts by mass to 35 parts by mass, and more preferably in the range of 4 parts by mass to 25 parts by mass, relative to 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) calculated as solids.

[0110] Other ingredients

[0111] The alkali-developable resin composition of the present invention may, of course, contain further additives as other components as needed within the scope of the object of the present invention.

[0112] Examples of such components include colorants such as pigments and dyes, thermal polymerization inhibitors, thermal curing catalysts, ultraviolet absorbers, plasticizers, flame retardants, antistatic agents, antioxidants, volatile agents, antioxidants, antibacterial / antifungal agents, defoaming agents, leveling agents, anti-sag agents, thickeners, adhesion-imparting agents, thixotropy-imparting agents, photoinitiator aids, sensitizers, photobase generators, thermoplastic resins, elastomers, organic fillers, release agents, surface treatment agents, dispersants, dispersing aids, surface modifiers, stabilizers, phosphors, and cellulose resins.

[0113] As the thermal curing catalyst, any known substance can be used within the range that does not hinder the effects of the present invention, and examples thereof 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 to these, guanamine, methylguanamine, benzoguanamine, melamine, an organic salt of melamine which is a reaction product of melamine with an organic acid such as phthalic acid, s-triazine derivatives such as 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.

[0114] The amount of the thermosetting catalyst added is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, based on solid content, per 100 parts by mass of the (B) carboxyl group-containing vinyl ester resin.

[0115] Among these, melamine is preferably added. As an antioxidant, it improves the adhesion between the substrate and the cured film of the alkaline-developable resin composition by inhibiting oxidation of the conductor (copper) on the substrate. It also acts as a thermal curing catalyst, promoting the reaction between epoxy groups and carboxyl groups. This improves the acid and alkali resistance, metal plating resistance, adhesion, and hardness of the dry film and cured product formed from the alkaline-developable resin composition.

[0116] Melamine may be optionally added to at least one of the base composition and the curing agent composition of the alkaline-developable resin composition of the present invention. Adding melamine to the curing agent composition is more preferred to further facilitate the aforementioned effects. The amount of melamine added is preferably 0.1 parts by mass to 20 parts by mass, and more preferably 0.5 parts by mass to 15 parts by mass, per 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) calculated as a solid content.

[0117] The base composition and curing agent composition of the alkali-developable resin composition of the present invention can be prepared by mixing and dispersing these components in predetermined amounts, for example, using a three-roll mill.

[0118] dry film

[0119] A dry film can be produced from the alkaline-developable resin composition of the present invention. The dry film of the present invention has a resin layer, which is obtained by coating the alkaline-developable resin composition of the present invention on a carrier film and drying it. When forming the dry film, first, in the case of a two-component system, the main agent composition and the curing agent composition are thoroughly mixed with each other to obtain the alkaline-developable resin composition of the present invention. After adjusting the viscosity to an appropriate level, the composition is diluted directly or as needed with a high-boiling point solvent, and then applied to a carrier film to a uniform thickness using a comma coater, a knife coater, a lip coater, a rod coater, an extrusion coater, a reverse coater, a transfer roll coater, a gravure coater, a spray coater, or the like. Thereafter, the applied composition is dried at a temperature of generally 50 to 130°C for 1 to 30 minutes to form a resin layer. There are no particular restrictions on the coating film thickness, but it is generally selected within the range of 10 to 150 μm, preferably 20 to 60 μm, based on the film thickness after drying.

[0120] As the carrier film, a plastic film is generally 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.

[0121] After forming a resin layer formed from the alkaline-developable resin composition of the present invention on a carrier film, it is preferable to further laminate a removable cover film on the surface of the resin layer to prevent dust and the like from adhering to the surface of the resin layer. Examples of the removable cover film include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper. The cover film may be any film as long as it is smaller than the adhesion between the resin layer and the carrier film when the cover film is peeled off.

[0122] It should be noted that in the present invention, the alkaline-developable resin composition of the present invention may be applied to the aforementioned cover film and dried to form a resin layer, and a carrier film may be laminated on the surface of the resin layer. In other words, in the present invention, when producing a dry film, either a carrier film or a cover film may be used as the thin film to which the curable composition of the present invention is applied.

[0123] Here, a tack-free resin layer can also be formed by adjusting the alkaline-developable resin composition of the present invention to a viscosity suitable for the coating method using, for example, a high-boiling-point solvent, and applying it to a substrate by dip coating, flow coating, roll coating, bar coating, screen printing, curtain coating, or the like, followed by volatilization and drying of the high-boiling-point solvent contained in the composition at a temperature of approximately 60 to 100° C. (temporary drying). Alternatively, when the composition is applied to a carrier film or a cover film, dried, and wound into a thin film, the resin layer can be formed by laminating the composition of the present invention to the substrate using a laminator or the like so that the layer is in contact with the substrate, and then peeling off the carrier film.

[0124] As the above-mentioned 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 use materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven fabric epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, and copper-clad laminates for high-frequency circuits using fluorine·polyethylene·polyphenylene ether (polyphenylene oxide)·cyanate ester, etc.

[0125] Cured material

[0126] When forming a cured product using the alkaline developing resin composition of the present invention, the composition is applied to a substrate, the solvent is evaporated and dried, and a resin layer is obtained. The obtained resin layer is exposed (light irradiated) so that the exposed portion (the portion irradiated with light) is cured. Specifically, by contact or non-contact method, active energy rays are selectively exposed through a photomask having a pattern, or a laser direct exposure machine is used to directly expose the pattern, and an alkaline aqueous solution (for example, a 0.3-3% by mass sodium carbonate aqueous solution) is used to develop the unexposed portion to form an etching resist pattern. Further heating to a temperature of about 100-180°C and heat curing (post-curing) is performed, thereby forming a cured product (cured film) having excellent properties such as heat resistance and pencil hardness.

[0127] The volatilization drying or thermal curing when forming the above-mentioned cured product can be carried out, for example, using a hot air circulation drying furnace, IR furnace, hot plate, convection oven, etc. (using a device with a heat source that uses steam to heat the air, a method of making the hot air in the dryer contact by convection, and a method of blowing it onto the support body using a nozzle).

[0128] In addition, as an exposure machine used in the above-mentioned active energy ray irradiation, any device that is equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, etc. and irradiates ultraviolet rays in the range of 350 to 450 nm can be used. Furthermore, a direct drawing device (for example, a laser direct imaging device that directly draws an image with a laser using 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 can usually be set to 20 to 1000 mJ / cm 2 , preferably can be set to 20 to 800 mJ / cm 2 within the range.

[0129] Next, in a development step, the resin layer after the exposure step is treated with a developer to remove unexposed portions of the resin layer, thereby forming a pattern film of the alkali-developable resin composition of the present invention.

[0130] Here, as the method used in the development step, an immersion method, a shower method, a spray method, a brush method, etc. can be used. As the developer, a sodium carbonate aqueous solution with a mass concentration of 0.5 to 5% can generally be used. Other alkaline aqueous solutions can also be used, such as alkaline aqueous solutions of potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, etc.

[0131] In this development step, the temperature of the developer is 20 to 40° C. and the development time is within 180 seconds.

[0132] In the development step, the obtained pattern film may be washed with a rinse solution as needed. As the rinse solution, distilled water, methanol, ethanol, isopropyl alcohol, etc. may be used alone or in combination.

[0133] electronic components

[0134] The present invention can also provide an electronic component comprising the cured product.

[0135] The alkaline-developable resin composition or dry film of the present invention can be used as protective films, electrical insulating layers, sealants, sealing materials for built-in electronic components, component embedding layers, adhesive layers for fixing electronic components, and the like for printed circuit boards, semiconductor elements, and the like. It is particularly suitable for high-density wiring requiring low dielectric constants and low dielectric loss tangents, electronic components that process high-frequency signals, and electronic components for vehicles and robots that require high-temperature and long-term reliability.

[0136] It should be noted that the electronic components in the present invention refer to components used in electronic circuits, including active components such as printed circuit boards, transistors, light-emitting diodes, laser diodes, etc., as well as passive components such as resistors, capacitors, inductors, connectors, etc.

[0137] Hereinafter, one embodiment of the present invention will be specifically described based on the examples, but it is of course not intended to limit the scope of the invention according to the claims of the present invention.

[0138] In addition, unless otherwise specified, the "parts" and "%" shown are based on mass.

[0139] Example

[0140] [Synthesis Example: Synthesis of Carboxyl Group-Containing Vinyl Ester Resin]

[0141] 1070 g of an o-cresol novolac-type epoxy resin (EPICLONN-695, manufactured by DIC Corporation, softening point 95°C, epoxy equivalent 214, average number of functional groups 7.6) (glycidyl group number (total number of aromatic rings): 5.0 mol), 360 g (5.0 mol) of acrylic acid, and 1.5 g of hydroquinone were added to 600 g of diethylene glycol dibutyl ether, and stirred until uniformly dissolved. Next, 4.3 g of triphenylphosphine was added, and the mixture was heated to 110°C and reacted for 2 hours. The temperature was then raised to 120°C and the reaction was continued for an additional 12 hours. To the resulting reaction solution, 415 g of diethylene glycol dibutyl ether and 456.0 g (3.0 mol) of tetrahydrophthalic anhydride were added, and the mixture was reacted at 110°C for 4 hours. The mixture was then cooled to obtain a carboxyl group-containing vinyl ester resin (varnish). The carboxyl vinyl ester resin (varnish) thus obtained had a solid content concentration of 65% by mass and an acid value of 89 mgKOH / g. Furthermore, the weight-average molecular weight (Mw) of the obtained carboxyl vinyl ester resin was 9000. It should be noted that the weight-average molecular weight of the obtained resin was measured using a high performance liquid chromatograph equipped with an LC-6AD pump manufactured by Shimadzu Corporation and three Shodex (registered trademark) columns KF-804, KF-803, and KF-802 manufactured by Showa Denko K.K.

[0142] [Examples 1 to 7 and Comparative Examples 1 to 4]

[0143] The components shown in Table 1 were pre-mixed in a blender at various blending amounts and then kneaded using a three-roll mill to prepare alkaline-developable resin compositions (two-component systems consisting of a base composition and a curing agent composition) of Examples 1 to 7 and Comparative Examples 1 to 4, respectively.

[0144] [Table 1]

[0145] The components described in Table 1 are as follows.

[0146] *1: Carboxyl vinyl ester resin obtained in Synthesis Example, solid content 65%, solvent content (carbitol acetate (normal solvent)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd.

[0147] *2: Carboxyl vinyl ester resin obtained in Synthesis Example (where only the solvent component was replaced), solid content 65%, solvent component (diethylene glycol dibutyl ether ((F) high boiling point solvent*18)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd.

[0148] *3: Organic bentonite: volatile agent, ORBEN M, manufactured by Shiraishi Calcium (Shanghai) International Trading Co., Ltd.

[0149] *4: Green color paste: Base product of 6Y-501, manufactured by TOYOCOLOR CO., LTD.

[0150] *5: Antioxidant: IRGANOX 1010, manufactured by BASF JAPAN LTD.

[0151] *6: Thermal curing catalyst DCDA (DICY), manufactured by Shanghai Xindi Chemical Co., Ltd.

[0152] *7: Defoaming agent: KSZ-118, manufactured by Zhejiang Shin-Etsu Fine Chemical Co., Ltd.

[0153] *8: Leveling agent: BYK-1790, manufactured by BYK Additives (Shanghai) Co., Ltd.

[0154] *9: Photopolymerization initiator: #784 bis(cyclopentadienyl)bis[2,6-difluoro-3-(1-pyrrolyl)phenyltitanium (Omnirad 784 manufactured by IGM Resins)

[0155] *10: Photopolymerization initiator: EAB, 4,4'-bis(diethylamino)benzophenone (manufactured by Daido Chemical Industry Co., Ltd.)

[0156] *11: Photopolymerization initiator: ITX, isopropylthioxanthone (manufactured by DKSH JAPAN)

[0157] *12: Photopolymerization initiator: #907: α-aminoacetophenone-based photopolymerization initiator (Omnirad 907 manufactured by IGM Resins) (2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one)

[0158] *13: Filler: HD25, talc, manufactured by Fushi (Shanghai) Trading Co., Ltd.

[0159] *14: Filler: A2, barium sulfate, manufactured by Foshan Anyi Nanomaterials Co., Ltd.

[0160] *15: Defoaming agent: DS-100, manufactured by Foshan Nanhai Datian Chemical Co., Ltd.

[0161] *16: Anti-sagging agent: BYK-R606, manufactured by BYK Additives (Shanghai) Co., Ltd.

[0162] *17: Conventional organic solvent: DPM, dipropylene glycol monomethyl ether, manufactured by Shanghai Hongze Chemical (boiling point 190°C)

[0163] *18: (F) High boiling point organic solvent: Diethylene glycol dibutyl ether, manufactured by Anhui Lixing New Materials Co., Ltd. (boiling point 254°C)

[0164] *19: Epoxy resin: 128E, manufactured by Nan Ya Plastics, bisphenol A epoxy resin, solid content 100%

[0165] *20: Epoxy resin: N-770, manufactured by DIC Corporation, phenol / modified novolac type epoxy resin, solid content 100%

[0166] *21: Epoxy resin: BNE200, bisphenol A novolac epoxy resin, manufactured by Tiantai High-tech (Guangzhou) Co., Ltd., solid content 100%

[0167] *22: Epoxy resin: TGIC-G, manufactured by Shanghai Xindi Chemical Co., Ltd.

[0168] *23: Photosensitive monomer: DPHA, dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd.

[0169] *24: Melamine: MELAMINE-JC, manufactured by Shanghai Xindi Chemical Co., Ltd.

[0170] *25: Conventional organic solvent: DPM, dipropylene glycol monoether, manufactured by Shanghai Hongze Chemical (boiling point 190°C)

[0171] *26: Hexadecanol ester, high boiling point organic solvent: Hexadecanol ester, manufactured by Wuhan Qiaofeng Chemical Technology Co., Ltd. (boiling point 281°C)

[0172] *27: GMA, glycidyl methacrylate, viscosity 10 mPa·s / 25°C, molecular weight 142.15, boiling point 189°C, manufactured by Sigma-Aldrich

[0173] *28: XY693, p-tert-butylphenyl glycidyl ether, viscosity 30 mPa·s / 25°C, molecular weight 206.28, boiling point 175°C, manufactured by Keikasei Kogyo Co., Ltd.

[0174] The following tests were performed on the obtained base composition, curing agent composition, and alkali-developable resin composition obtained by mixing these in Examples and Comparative Examples.

[0175] <VOCs content>

[0176] According to GB / T 38608-2020, when the expected VOC content (mass fraction) in the alkaline-developable resin composition is greater than 15%, it is determined by the difference method; when the expected VOC content (mass fraction) in the alkaline-developable resin composition is less than or equal to 15%, it is determined by gas chromatography.

[0177] Dispersibility

[0178] Use a 0-50μm scraper fineness gauge. Wipe the gauge clean before testing. After the solvent has completely evaporated, confirm that there is no residue on the surface. Remove any surface dust with a static-eliminating brush. With the 0 mark on the fineness measuring table facing the tester, take a small amount of the alkaline-developable resin composition sample from the above-mentioned Examples and Comparative Examples and place it above the maximum scale mark. The amount of sample should be greater than the volume of the deep groove of the fineness gauge. With the blade of the scraper perpendicular to the deep groove of the measuring table, press the fineness gauge downward perpendicularly to the flat surface of the fineness gauge. Push the scraper toward the 0 mark at a constant speed (scraping for approximately 4 seconds).

[0179] Line Assessment

[0180] If lines longer than 5mm appear due to friction between the particles of the sample being tested and the scraper, and three or more lines appear in the same slot and within the same scale range, the upper scale line within the scale range where the lines appear is the reading. If the readings of the left and right slots differ, the larger reading is used as the test result.

[0181] Particle Assessment

[0182] Observe the particles in the channel. If there are 5 or more particles in the same channel and within the same scale range, the upper scale line within the scale range is used as the reading. If the readings of the left and right channels are inconsistent, the larger reading shall prevail as the test result.

[0183] Judgment criteria: If the line evaluation is 15μm or less and the particle evaluation is 35μm or less, the dispersion is judged as good "○";

[0184] Otherwise, the dispersion was judged as poor "×".

[0185] <Dry to touch>

[0186] The alkaline-developable resin compositions of the above-mentioned examples and comparative examples were applied to the entire surface of a copper-clad laminate polished with a polishing roller by screen printing, and dried at 80°C for 30 minutes to prepare a substrate. The dryness to touch of the coating surface was evaluated.

[0187] ○: No stickiness at all

[0188] △: Slightly sticky

[0189] ×: sticky

[0190] <Sensitivity division (photosensitivity)>

[0191] The copper-free substrate was polished with a jet scrubber, washed with water, and dried. The alkaline-developable resin compositions of the above-mentioned examples and comparative examples were applied by screen printing and dried in a hot air circulation drying oven at 80°C for 30 minutes. After drying, the substrate was exposed to light at 400 mJ / cm using a step tablet (Kodak No. 2). 2 The photosensitivity was evaluated by the number of remaining steps on the step meter after exposure to an exposure dose of 100 nm and development for 60 seconds using a 1 wt% sodium carbonate aqueous solution at 30°C and a spray pressure of 0.2 MPa. The higher the number of steps on the step meter, the better the photosensitivity.

[0192] <Development Residue (Development Properties)>

[0193] The alkaline-developable resin compositions of the above-described Examples and Comparative Examples were applied to the entire surface of a copper-clad laminate substrate, dried at 75°C for 60 minutes, and then left to cool at 20°C for 10 minutes to form a 25 μm thick resin layer. After development for 60 seconds using a 1% by mass sodium carbonate aqueous solution at 30°C and a spray pressure of 2 kg, the residual composition on the substrate surface was evaluated.

[0194] ○: No developing residue

[0195] △: Slight development residue

[0196] ×: Severe residual development

[0197] Pencil hardness

[0198] The alkaline-developable resin compositions of the above-mentioned examples and comparative examples were applied by screen printing to the entire surface of a copper-clad laminate substrate that had been pre-treated by polishing and grinding. The substrate was dried at 80°C for 30 minutes and cooled to room temperature to form a resin layer with a thickness of 25 μm. The resin layer was pattern-exposed using a 7 kW conventional halogen exposure machine (HMW-680GW manufactured by ORC) equipped with a halogen lamp light source. The resin layer was then developed for 60 seconds in a 1 wt % sodium carbonate aqueous solution, a pressure of 0.2 MPa, and a liquid temperature of 30°C. The composition was then dried (post-cured) for 60 minutes in a hot air circulation drying oven at 150°C to obtain an evaluation substrate. The pencil hardness of the resin (cured product) surface of the evaluation substrate was measured according to JIS K 5600-5-4, and the measurement results are recorded in Table 1. A larger pencil hardness value indicates a higher pencil hardness.

[0199] <Heat resistance>

[0200] The alkaline-developable resin compositions of the above-mentioned examples and comparative examples were applied by screen printing to the entire surface of a copper-clad laminate substrate that had been pre-treated by polishing and grinding, dried at 80°C for 30 minutes, and cooled to room temperature to form a resin layer with a thickness of 25 μm. The resin layer was exposed to light using a 7 kW conventional halogen exposure machine (HMW-680GW manufactured by ORC) equipped with a halogen lamp light source at a rate of 400 mJ / cm 2 The entire surface was exposed to an exposure dose of 100 nm, and developed using a 1% mass concentration sodium carbonate aqueous solution at 30°C and a spray pressure of 0.2 MPa for 60 seconds. The composition was then dried (post-cured) in a hot air circulation drying oven adjusted to 150°C for 60 minutes to obtain an evaluation substrate.

[0201] The evaluation substrate coated with rosin-based flux was immersed in a solder bath pre-set at 288°C. After the flux was washed with modified alcohol, the resist layer (cured material) was visually evaluated for swelling and peeling. The evaluation criteria were as follows.

[0202] ◎: The resist layer (cured material) bulges and peels off when the 10-second immersion is repeated more than 6 times

[0203] ○: The resist layer (cured material) bulges or peels off when the immersion is repeated 4 or more times but less than 6 times for 10 seconds.

[0204] △: The resist layer (cured material) bulges and peels off when the 10-second immersion is repeated less than 4 times

[0205] The results shown in Table 1 demonstrate that the alkaline-developable resin composition of the present invention exhibits excellent dispersibility, photosensitivity, and developability while reducing VOC content. Furthermore, its cured product exhibits high pencil hardness and excellent heat resistance, while also improving the dry-to-touch properties of the coating film.

[0206] On the other hand, the main agent composition of Comparative Example 1 contained a conventional solvent and did not contain the high-boiling-point solvent (F). As a result, the VOC content exceeded the standard. Although the dispersibility and developability of the resin composition were evaluated well, the heat resistance of the cured product could not be considered excellent. Although the main agent composition of Comparative Example 2 contained the high-boiling-point solvent (F), which significantly reduced the VOC content, the curing agent composition contained a solvent, hexadecyl ester, with a boiling point of 281°C. Although this had little effect on the dispersibility and photosensitivity of the resin composition, or the pencil hardness of the resulting cured product, the developability and the dry-to-touch properties of the resulting coating were evaluated poorly, and the cured product had poor heat resistance. The main agent composition of Comparative Example 3 includes (F) a high-boiling-point solvent, and the curing agent composition contains glycidyl methacrylate (GMA) as a reactive diluent (G-1) having a viscosity of 2 mPa·s or more and 15 mPa·s or less. However, the inclusion of 25 parts by mass of glycidyl methacrylate (GMA) relative to 100 parts by mass of the carboxyl vinyl ester resin (B) on a solid basis results in an excessively low viscosity of the system, poor dispersibility, and poor dry-to-touch properties of the resulting coating surface. Although the resin composition has excellent photosensitivity, it has poor developability, and the cured product also has poor heat resistance. The main agent composition of Comparative Example 4 includes (F) a high-boiling-point solvent, and the curing agent composition contains p-tert-butylphenyl glycidyl ether as (G-2) a reactive diluent having a viscosity greater than 15 mPa·s and less than 50 mPa·s. However, the inclusion of 30 parts by mass of p-tert-butylphenyl glycidyl ether per 100 parts by mass of (B) the carboxyl group-containing vinyl ester resin, calculated as the solid content, results in a low viscosity of the system, poor dispersibility, and poor dryness to touch on the coating surface. While this has little effect on the photosensitivity of the resin composition and the pencil hardness of its cured product, the developability of the resin composition and the heat resistance of its cured product are both poor.

[0207] In contrast, the alkaline-developable resin compositions of each Example, which included an appropriate amount of the reactive diluent (G) in the curing agent composition, not only had significantly lower VOCs contents (to 10% or less), but also exhibited further improved dispersibility, photosensitivity, and developability. The resulting cured products exhibited excellent pencil hardness and heat resistance, and the resulting coating films also exhibited excellent set-to-touch properties. Furthermore, in Examples 3 and 4, where the curing agent composition contained only glycidyl methacrylate (GMA), a reactive diluent (G-1) with a viscosity of 2 mPa·s to 15 mPa·s, as the reactive diluent (G), the resulting alkaline-developable resin compositions not only had reduced VOCs contents (to 7% or less), but also exhibited excellent dispersibility and developability, further improved photosensitivity, and excellent pencil hardness and heat resistance. The resulting coating films also exhibited excellent set-to-touch properties. In Example 7, in which the curing agent composition contains both GMA as a reactive diluent (G-1) with a viscosity of 2 mPa·s to 15 mPa·s, and XY693 as a reactive diluent (G-2) with a viscosity of greater than 15 mPa·s to 50 mPa·s, the resulting alkaline-developable resin composition not only has a reduced VOC content (to 7% or less), but also exhibits excellent dispersibility and developability, and further enhances photosensitivity. Furthermore, the resulting cured product exhibits excellent pencil hardness and heat resistance, and the resulting coating film also exhibits excellent dry-to-touch properties.

[0208] As can be seen, the alkaline-developable resin composition of the present invention poses less environmental hazards and exhibits superior dispersibility, photosensitivity, and developability. Furthermore, the pencil hardness and heat resistance of the resulting cured product are further improved, and the resulting coating film also exhibits excellent dry-to-touch properties. The composition is particularly suitable for use in dry films, cured products for printed circuit boards employing photolithography, and electronic components comprising the cured product.

Claims

1. An alkaline-developable resin composition, comprising at least a two-component resin composition, characterized in that: The alkaline-developable resin composition comprises: (A) an epoxy resin, (B) a carboxyl group-containing vinyl ester resin, (C) a photopolymerization initiator, (D) a photosensitive monomer, (E) an inorganic filler, (F) a high-boiling-point solvent, and (G) a reactive diluent. The boiling point of the high boiling point solvent (F) is higher than 250°C and lower than 280°C, The reactive diluent (G) comprises at least one selected from the group consisting of (G-1) a reactive diluent having a viscosity of 2 mPa·s to 15 mPa·s and (G-2) a reactive diluent having a viscosity of greater than 15 mPa·s to 50 mPa·s, wherein the reactive diluent (G-1) having a viscosity of 2 mPa·s to 15 mPa·s and (G-2) having a viscosity of greater than 15 mPa·s to 50 mPa·s are epoxy compounds having only one epoxy group per molecule. The content of the reactive diluent (G-1) having a viscosity of 2 mPa·s to 15 mPa·s is greater than 5 parts by mass and less than 25 parts by mass, and the content of the reactive diluent (G-2) having a viscosity of greater than 15 mPa·s to 50 mPa·s is greater than 5 parts by mass and less than 30 parts by mass, relative to 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) in terms of solid content.

2. The alkaline-developable resin composition according to claim 1, wherein The reactive diluent (G-1) having a viscosity of 2 mPa·s to 15 mPa·s is an epoxy compound having an unsaturated group, and the reactive diluent (G-2) having a viscosity of greater than 15 mPa·s to 50 mPa·s is an epoxy compound having an aromatic ring.

3. The alkaline-developable resin composition according to claim 1 or 2, wherein In the at least two-component system, each component may optionally contain other solvents in addition to the (G) reactive diluent.

4. The alkaline-developable resin composition according to claim 1 or 2, wherein In the at least two-component system, the component containing the (G) reactive diluent does not contain any solvent other than the (G) reactive diluent.

5. The alkaline-developable resin composition according to claim 1 or 2, wherein The reactive diluent (G-1) having a viscosity of 2 mPa·s to 15 mPa·s is at least one selected from 3,4-epoxycyclohexylmethyl (meth)acrylate and glycidyl (meth)acrylate, and the reactive diluent (G-2) having a viscosity of greater than 15 mPa·s to 50 mPa·s is p-tert-butylphenyl glycidyl ether.

6. The alkaline-developable resin composition according to claim 1 or 2, wherein The content of volatile organic compounds is less than 10% by mass. 7 . A dry film obtained by applying the alkali-developable resin composition according to claim 1 to a carrier film and drying the resulting film.

8. A cured product, characterized in that: This is obtained by curing the alkali-developable resin composition according to any one of claims 1 to 6.

9. A cured product, characterized in that: This is obtained by curing the resin layer of the dry film according to claim 7.

10. An electronic component, characterized in that: A cured product according to claim 8 or 9.