Alkali-developable resin composition, dry film, cured product, and electronic component having the cured product

Abstract

The present invention provides an alkali-developable resin composition, a dry film, a cured product, and an electronic component having the cured product, which exhibit excellent appearance, character adhesion, adhesion, and crack resistance, low volatility, and excellent ink performance. The alkali-developable resin composition is an at least two-component resin composition comprising (A) an epoxy resin, (B) a carboxyl group-containing vinyl ester resin, (C) a photopolymerization initiator, (D) a photosensitive monomer, (E) an inorganic filler, and (F) a high-boiling-point solvent, wherein the (B) carboxyl group-containing vinyl ester resin, the (C) photopolymerization initiator, the (E) inorganic filler, and the (F) high-boiling-point solvent are contained in a resin composition different from the (A) epoxy resin and the (D) photosensitive monomer, and the boiling point of the (F) high-boiling-point solvent is greater than 250°C and not greater than 280°C.

Description

[Technical Field]

[0001] The present invention relates to an alkali-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 alkali-developable resin composition, a cured product suitable for printed wiring boards such as solder resist, and an electronic component having the cured product. [Background technology]

[0002] In the manufacture of printed circuit boards, curable resin compositions are typically used to form permanent coatings such as solder resist layers. Dry film-type compositions, liquid compositions, and other types of curable resin compositions have been developed. Furthermore, in order to achieve miniaturization of electronic components, high-precision design structures, and application to complex manufacturing methods, it is expected that curable resin compositions will be patterned using the principles of photolithography, thereby enabling microfabrication. In recent years, from the perspective of environmental protection, alkaline development types that can be developed with a dilute, weak alkaline aqueous solution have become mainstream.

[0003] Until now, solder resist (also known as solder resist ink) has been used on printed circuit boards as a protective material for the circuits on the circuit board. Conventional solder resists use highly volatile, low-boiling-point solvents, which often cause defects such as bubbles and pinholes during application, and their high volatility also places a heavy burden on the environment.

[0004] With increasing environmental awareness, printed circuit boards, which use many chemicals during their production, are subject to increasingly strict standards and regulations aimed at reducing volatile organic compounds (VOCs). A volatile organic compound is 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, alkenes, halogenated hydrocarbons, esters, aldehydes, ketones, and other compounds. Common VOCs include benzene, toluene, xylene, styrene, trichloroethylene, chloroform, trichloroethane, diisocyanates, and diisocyanate toluenes.

[0005] Patent Document 1 uses water instead of high-boiling-point solvents to reduce VOC emissions. However, the solder resist ink has disadvantages such as poor storage stability (the carboxyl groups of the acrylic resin in the ink, which are involved in the development reaction, become hydrophilic and then become surrounded by water molecules. This weakens the reaction between the carboxyl groups and the sodium carbonate in the developer, reducing the ink's developability and, in severe cases, causing developer staining) and a complex process. Furthermore, the ink's properties limit its range of use. Patent Document 2 uses eco-friendly solvents (e.g., one or more of ethylene glycol butyl ether (boiling point 171°C), diacid 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 exceeds 20%. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] CN108219585A [Patent Document 2] CN113604103A Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional imageable solder resists typically use aromatic hydrocarbon solvents (such as the heavy aromatic hydrocarbon solvent Naphtha S-150) and low-boiling ester or ether solvents (such as dipropylene glycol monomethyl ether and diethylene glycol ethyl ether acetate). The main problems are that they contain more than 20% volatile organic compounds (VOCs), which have a significant negative impact on the environment, and because these solvents evaporate quickly, they are prone to forming bubbles when printed on thick copper plates (for example, copper thickness of 2 oz (70 μm) or more) or when the printed film is thick, which can cause defects such as pits (unevenness or wrinkles on the painted surface) and pinholes (marks left by bubbles or a surface that looks like it was poked with a pin).

[0008] Therefore, there is a demand for alkali-developable resin compositions that, while ensuring ink performance, have low volatility (detection level of VOCs of 10% or less), excellent photosensitivity, and excellent hardness of the cured product (coating film), as well as improved character adhesion, adhesion, and crack resistance during thermal cycling.

[0009] Furthermore, from the viewpoint of ink performance, there is a need for an alkali-developable resin composition that is less likely to generate bubbles when printing on thick copper substrates, has excellent coating film appearance, has better leveling properties, reduces defects such as pits and pinholes in the coating film, and has better adhesion.

[0010] If the coating film has excellent dryness to the touch, no tack marks will appear on the surface of the coating film upon exposure to light. On the other hand, if the dryness to the touch is poor, the coating film surface will be highly viscous, making tack marks more likely to appear on the surface of the coating film upon exposure to light, and these marks will likely remain on the surface of the cured coating film after curing, deteriorating the appearance.

[0011] Therefore, an object of the present invention is to provide an alkali-developable resin composition which produces a coating film with excellent tack-drying properties, and which exhibits excellent appearance, character adhesion, adhesion, and crack resistance in a cured product, and which has low volatility and excellent ink performance.

[0012] Another object of the present invention is to provide a dry film and a cured product which are obtained using such an alkali-developable solder resist composition and which have the above-mentioned excellent properties, as well as a printed wiring board having formed thereon a cured film such as a solder resist as the cured product. [Means for solving the problem]

[0013] As a result of intensive research, the present inventors have discovered an alkali-developable resin composition comprising at least a two-component resin composition, the alkali-developable resin composition comprising: (A) an epoxy resin; (B) a carboxyl group-containing vinyl ester resin; (C) a photopolymerization initiator; (D) a photosensitive monomer; (E) an inorganic filler; and (F) a high-boiling point solvent, the (B) carboxyl group-containing vinyl ester resin, the (C) photopolymerization initiator, the (E) inorganic filler, and the (F) high-boiling point solvent are contained in a resin composition different from that of the (A) epoxy resin and the (D) photosensitive monomer; The inventors have found that the above problems can be solved by using an alkali-developable resin composition in which the boiling point of the (F) high-boiling-point solvent is more than 250°C and not more than 280°C, and have thus completed the present invention.

[0014] A preferred embodiment of the present invention relates to an alkali-developable resin composition, wherein the (F) high-boiling point solvent is at least one or more selected from the group consisting of polyol ethers, polyol esters, organic acid alkyl esters, and aliphatic hydrocarbons.

[0015] A more preferred embodiment of the present invention relates to an alkali-developable resin composition, wherein the (F) high-boiling point solvent is at least one or more solvents selected from the group consisting of diethylene glycol dibutyl ether, tripropylene glycol n-butyl ether, tetraethylene glycol dimethyl ether, and tripropylene glycol dibutyl ether.

[0016] An even more preferred embodiment of the present invention relates to an alkali-developable resin composition, wherein the content of the (F) high-boiling point solvent is 40 to 80 parts by mass, calculated as solid content, per 100 parts by mass of the (B) carboxyl group-containing vinyl ester resin.

[0017] Furthermore, a further preferred embodiment of the present invention relates to an alkali-developable resin composition, wherein at least one component of the at least two-component system further contains a solvent other than the (F) high-boiling point solvent.

[0018] A further preferred embodiment of the present invention relates to an alkali-developable resin composition having a volatile organic compound content of 10% or less by mass fraction.

[0019] Another aspect of the present invention relates to a dry film having a resin layer obtained by applying the above-mentioned alkali-developable resin composition to a carrier film and drying the applied resin layer.

[0020] Yet another aspect of the present invention relates to the above alkali-developable resin composition, which is used as a solder resist material.

[0021] Yet another aspect of the present invention relates to a cured product obtained by curing an alkali-developable resin composition, a cured product obtained by curing a resin layer of a dry film, and an electronic component having these cured products. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide an alkali-developable resin composition which produces a coating film with excellent dryness to touch, and which provides a cured product obtained by curing the alkali-developable resin composition with excellent appearance, character adhesion, adhesion, and crack resistance, and which has low volatility and excellent photosensitivity and ink performance.

[0023] Furthermore, according to the present invention, it is possible to provide a dry film and a cured product obtained by using such an alkali-developable resin composition, which are excellent in the above-mentioned properties, as well as electronic components, such as printed wiring boards, having formed thereon a cured coating, such as a solder resist, as the cured product. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a photograph showing cracking of the solder resist for evaluating thermal shock resistance in a comparative example (NG: cracks present). [Figure 2] 1 is a photograph showing that the solder resist used to evaluate thermal shock resistance in an example does not crack (OK: no cracks). DETAILED DESCRIPTION OF THE INVENTION

[0025] The alkali-developable resin composition of the present invention preferably comprises at least a two-component resin composition. For example, a two-component system may be used in which one resin composition is a base composition and another resin composition is a curing agent composition. In this case, for example, the base composition 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 composition preferably comprises at least (A) an epoxy resin and (D) a photosensitive monomer.

[0026] In this case, from the viewpoint of preventing chemical reactions during storage, it is preferable that (A) the epoxy resin and (B) the carboxyl group-containing vinyl ester resin are contained in different compositions, and that (D) the photosensitive monomer and (C) the photopolymerization initiator are contained in different compositions.

[0027] Furthermore, when (B) a carboxyl group-containing vinyl ester resin and (C) a photopolymerization initiator are present in the same composition, the composition may have poor appearance and coarse particles, although the detailed mechanism is unclear. As a result of research, the inventors have found that by using a base resin containing at least (B) a carboxyl group-containing vinyl ester resin, (C) a photopolymerization initiator, and (F) a high-boiling point solvent within a specific boiling point range, the VOC content can be reduced and this problem can be resolved.

[0028] Each component constituting the alkali-developable resin composition of the present invention will now be described.

[0029] (A) Epoxy resin The (A) epoxy resin functions as a thermosetting component in the alkali-developable resin composition and forms a cured product.

[0030] As such epoxy resin (A), a known and commonly used multifunctional epoxy resin having at least two epoxy groups in one molecule can be used.

[0031] The (A) epoxy resin may be in a liquid state, or may be in a solid or semi-solid state. Preferred examples of polyfunctional epoxy resins include bisphenol A epoxy resins, brominated epoxy resins, novolac epoxy resins, bisphenol F epoxy resins, hydrogenated bisphenol A epoxy resins, glycidylamine epoxy resins, hydantoin epoxy resins, alicyclic epoxy resins, trihydroxyphenylmethane epoxy resins, bixylenol or biphenol epoxy resins or mixtures thereof, bisphenol S epoxy resins, bisphenol A novolac epoxy resins, tetraphenylolethane epoxy resins, heterocyclic epoxy resins, diglycidyl phthalate resins, tetraglycidylxylenoylethane resins, naphthalene group-containing epoxy resins, epoxy resins having a dicyclopentadiene skeleton, glycidyl methacrylate copolymer epoxy resins, cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resins, epoxy-modified polybutadiene rubber derivatives, CTBN-modified epoxy resins, and epoxy resins having an isocyanuric ring, but the present invention is not limited to these.

[0032] These epoxy resins can be used alone or in combination of two or more.

[0033] The "epoxy resin that is solid or semi-solid at room temperature" in component (A) can also be a known or commonly used epoxy resin. 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-A Plastics Co., Ltd.), bisphenol F epoxy resins (jER4004P manufactured by Mitsubishi Chemical Corporation), naphthalene epoxy resins (HP-4700 manufactured by DIC Corporation), naphthalene skeleton-containing multifunctional solid epoxy resins (NC-7000 manufactured by Nippon Kayaku Co., Ltd.), trisphenol epoxy resins (EPPN-502H manufactured by Nippon Kayaku Co., Ltd.), dicyclopentadiene skeleton-containing multifunctional solid epoxy resins (Epicron HP-7200 manufactured by DIC Corporation), phosphorus-containing epoxy resins (TX0712 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), and tris(2,3-epoxypropyl)isocyanurate (Nissan Chemical Industries, Ltd.). TEPIC), and examples of epoxy resins that are semi-solid at room temperature include bisphenol A type epoxy resins (jER834 manufactured by Mitsubishi Chemical Corporation) and naphthalene type epoxy resins (HP-4032 manufactured by DIC Corporation).

[0034] Here, in the present invention, being solid or semi-solid at room temperature means being solid or semi-solid at 15° C. Whether a substance is solid or semi-solid can be determined in accordance with the "Method for Confirming Liquid State" in Appendix 2 of the Ministerial Ordinance on the Testing and Properties of Hazardous Materials (Ministry of Home Affairs Ordinance No. 1 of 1989).

[0035] The biphenyl-type epoxy resin in component (A) may be a known, commonly used multifunctional epoxy resin having a biphenyl skeleton, such as a biphenyl-skeleton-containing multifunctional solid epoxy resin (NC-3000H, NC-3000, manufactured by Nippon Kayaku Co., Ltd.) or a biphenyl-type epoxy resin (YX-4000, YL-6121HA, manufactured by Mitsubishi Chemical Corporation).

[0036] Examples of novolac epoxy resins in component (A) include cresol novolac epoxy resins (Epiclon N-690 manufactured by DIC Corporation), phenol novolac epoxy resins (Epiclon N-770 manufactured by DIC Corporation, jER152 manufactured by Mitsubishi Chemical Corporation), and bisphenol A novolac epoxy resins (BNE200D75 manufactured by Shanghai Hongze Chemical Co., Ltd.).

[0037] Examples of the epoxy resin having an isocyanuric ring in the component (A) include triglycidyl isocyanurate epoxy resin (TGIC-G, manufactured by Shanghai Xinxin Di Chemical Co., Ltd.).

[0038] The content of the epoxy resin (A) as described above is preferably in the range of approximately 30 to 90 parts by mass, more preferably 40 to 80 parts by mass, per 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) in terms of solid content.

[0039] (B) Carboxyl group-containing vinyl ester resin The (B) carboxyl group-containing vinyl ester resin used in the present invention is preferably a carboxyl group-containing resin containing an ethylenically unsaturated double bond in the molecule from the viewpoints of alkali developability, photocurability, and development resistance. Furthermore, those in which the unsaturated double bond is derived from acrylic acid, methacrylic acid, or a derivative thereof are more preferred. Specific examples of the (B) carboxyl group-containing vinyl ester resin are shown below.

[0040] (1) A carboxyl group-containing vinyl ester resin obtained by copolymerizing an unsaturated carboxylic acid such as (meth)acrylic acid with one or more other compounds having an unsaturated double bond. (2) Carboxyl group-containing vinyl ester resins obtained by adding ethylenically unsaturated groups as pendant groups to copolymers of unsaturated carboxylic acids such as (meth)acrylic acid and one or more other compounds having unsaturated double bonds using compounds having epoxy groups and unsaturated double bonds, such as glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate, or (meth)acryloyl chloride. (3) A carboxyl group-containing vinyl ester resin obtained by reacting a copolymer of a compound having an epoxy group and an unsaturated double bond, such as glycidyl (meth)acrylate or 3,4-epoxycyclohexylmethyl (meth)acrylate, with an unsaturated carboxylic acid, such as (meth)acrylic acid, and then reacting the resulting secondary hydroxyl group with a polybasic acid anhydride. (4) A carboxyl group-containing vinyl ester resin 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. (5) A carboxyl group-containing vinyl ester resin obtained by reacting a polyfunctional epoxy compound with an unsaturated monocarboxylic acid and then reacting the resulting hydroxyl group with a saturated or unsaturated polybasic acid anhydride. (6) A vinyl ester resin containing hydroxyl and carboxyl groups, obtained by reacting a hydroxyl group-containing polymer such as a polyvinyl alcohol derivative with a saturated or unsaturated polybasic acid anhydride, and then reacting the resulting carboxylic acid with a compound having an epoxy group and an unsaturated double bond in one molecule. (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. (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 then reacting a saturated or unsaturated polybasic acid anhydride with the primary hydroxyl groups of the resulting modified oxetane resin. (9) A carboxyl group-containing vinyl ester resin obtained by reacting a bifunctional epoxy compound with an unsaturated monocarboxylic acid and then reacting the resulting hydroxyl group with a saturated or unsaturated polybasic acid anhydride. (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 then adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the hydroxyl groups present in the side chains. (11) A carboxyl group-containing vinyl ester resin obtained by further epoxidizing the hydroxyl groups of the polyfunctional epoxy resin (10) with epichlorohydrin, reacting the resulting polyfunctional epoxy resin with (meth)acrylic acid, and adding a polybasic acid anhydride to the resulting hydroxyl groups. (12) A carboxyl group-containing vinyl ester resin obtained by adding a cyclic ether such as ethylene oxide or a cyclic carbonate such as propylene carbonate to a polyfunctional phenol compound such as a novolac resin, partially esterifying the resulting hydroxyl groups with (meth)acrylic acid, and reacting the remaining hydroxyl groups with a polybasic acid anhydride. (13) A carboxyl group-containing vinyl ester resin 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 (10) to (12) above.

[0041] Of these examples, particularly preferred are the cresol novolac type and phenol novolac type, and the carboxyl group-containing vinyl ester resins (5), (10), (11), (12) and (13) above.

[0042] In this specification, (meth)acrylate is a general term for acrylate, methacrylate and mixtures thereof, and the same applies to other similar expressions.

[0043] The carboxyl group-containing vinyl ester resin (B) described above has many free carboxyl groups in the side chains of the main chain polymer, which makes it possible to develop it with a dilute alkaline aqueous solution.

[0044] The acid value of the (B) carboxyl group-containing vinyl ester resin is preferably in the range of 40 to 200 mgKOH / g, more preferably 45 to 120 mgKOH / g. If the acid value of the carboxyl group-containing resin is less than 40 mgKOH / g, alkaline development becomes difficult. On the other hand, if the acid value exceeds 200 mgKOH / g, dissolution of the exposed area in the developer is accelerated, resulting in unnecessarily thin lines, and the exposed and unexposed areas are dissolved and peeled indistinguishably by the developer, making it difficult to draw a normal resist pattern, which is undesirable.

[0045] The weight-average molecular weight of the (B) carboxyl group-containing vinyl ester resin varies depending on the resin skeleton, but is generally in the range of 2,000 to 150,000, and preferably 5,000 to 100,000. If the weight-average molecular weight is less than 2,000, the tack-free properties (dryness to the touch) after application to the substrate and drying may be poor. Furthermore, the moisture resistance of the coating film after exposure may be poor, the film obtained during development may be reduced, and resolution may be significantly reduced. On the other hand, if the weight-average molecular weight exceeds 150,000, the developability may be significantly impaired and storage stability may be reduced.

[0046] (C) Photopolymerization initiator Examples of the (C) photopolymerization initiator include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, and bis-(2,6-dimethoxybenzoyl)-2,4,4-thiazolinone. Bisacylphosphine oxides such as 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, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, and 2-methylbenzoyldiphenylphosphine oxide. monoacylphosphine oxides such as phosphine 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-propan-1-one, and 2-hydroxy hydroxyacetophenones such as 2-methyl-1-phenylpropan-1-one; benzoins 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.

[0047] The content of the (C) photopolymerization initiator is preferably 5 to 25 parts by mass relative to 100 parts by mass of the (B) carboxyl group-containing resin, calculated as solid content. When the content is 5 parts by mass or more, the surface curing property is good, and when the content is 25 parts by mass or less, halation is unlikely to occur and good resolution can be obtained.

[0048] (D) Photosensitive monomer The (D) photosensitive monomer is preferably, for example, a compound having one or more ethylenically unsaturated groups in the molecule. The (D) photosensitive monomer containing such an ethylenically unsaturated group aids in photocuring of the (B) carboxyl group-containing vinyl ester resin by irradiation with active energy rays, thereby curing the alkali-developable resin composition.

[0049] The photosensitive monomer (D) preferably used in the present invention is, for example, methyl α-(allyloxymethyl)acrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,Bifunctional compounds such as diol diacrylates such as 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, bisphenol A PO adduct diacrylate, diacrylates having a cyclic structure such as tricyclodecane dimethanol diacrylate, hydrogenated dicyclopentadienyl diacrylate, and cyclohexyl diacrylate, and methacrylate monomers corresponding thereto. Examples of suitable acrylates include polyfunctional acrylates such as trifunctional (meth)acrylate, 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 phosphate triacrylate, epichlorohydrin-modified glycerol triacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, and silsesquioxane-modified versions of these, as well as corresponding methacrylate monomers, trifunctional methacrylate esters, and polyfunctional (meth)acrylates such as ε-caprolactone-modified tris(acryloxyethyl)isocyanurate, and combinations of two or more of these.

[0050] The content of such (D) photosensitive monomer is preferably in the range of 2 to 20 parts by mass, more preferably 4 to 15 parts by mass, based on 100 parts by mass of (B) carboxyl group-containing vinyl ester resin, calculated as solid content.

[0051] If the content of the (D) photosensitive monomer is within this range, the alkali-developable resin composition will have sufficient photocurability, will exhibit better patterning during development, and will also exhibit good tack-dry properties.

[0052] (E) Inorganic filler In the present invention, the inorganic filler (E) may be used alone or in combination of two or more kinds.

[0053] The blending amount of the (E) inorganic filler is preferably in the range of 35 to 200 parts by mass, and more preferably in the range of 50 to 150 parts by mass, per 100 parts by mass of the (B) carboxyl group-containing vinyl ester resin, calculated as solid content. When the blending amount of the (E) inorganic filler is 35 parts by mass or more, a cured film with superior solder heat resistance, insulation reliability, and heat discoloration resistance tends to be obtained. When the blending amount of the (E) inorganic filler is 200 parts by mass or less, an alkali-developable resin composition with superior defoaming properties, resolution, and deep curing properties tends to be obtained.

[0054] Examples of (E) inorganic fillers include titanium oxide, silica, barium sulfate, barium titanate, Neuburg silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, etc. Among these, from the viewpoint of improving mechanical properties, heat resistance, processability, etc., at least one of talc, silica, and barium sulfate is preferred, and it is preferable that the base material contains an inorganic filler, and it is preferable to use barium sulfate as this inorganic filler, which can suppress cure shrinkage of the cured product of the alkali-developable resin composition and improve properties such as adhesion and hardness.

[0055] The (E) inorganic filler may be surface-treated, and more preferably, the surface thereof is subjected to a surface treatment that allows the introduction of a curable reactive group.

[0056] Here, the curable reactive group refers to a group that undergoes a curing reaction with (A) an epoxy resin 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 a methacrylic group, an acrylic group, a vinyl group, and a styryl group. Examples of the thermosetting reactive group include an epoxy group, an amino group, a hydroxyl group, a carboxyl group, an isocyanate group, an imino group, an oxetanyl group, a mercapto group, a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an ethoxyethyl group, and an oxazoline group.

[0057] (E) The method for introducing curable reactive groups onto the surface of the inorganic filler is not particularly limited, and can be carried out using a known, commonly used method. The surface of the inorganic filler can be treated with a surface treatment agent having a curable reactive group, such as a coupling agent having a curable reactive group as an organic group. Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, a zirconium coupling agent, and an aluminum coupling agent. Examples of surface-treated inorganic fillers that do not have curable reactive groups include inorganic fillers that have been treated with silica-alumina, titanate-based coupling agents, aluminate-based coupling agents, or organically treated.

[0058] The average particle size (D50) of the (E) inorganic filler is preferably 2000 nm or less, more preferably 1200 nm or less, and the lower limit of the average particle size (D50) is preferably 0.1 nm or more.

[0059] (E) The smaller the average particle size of the inorganic filler, the less diffuse reflection there is during light irradiation, making it easier to finely pattern the cured product. The average particle size (D50) can be determined using a laser diffraction particle size distribution analyzer and a dynamic light scattering analyzer. Examples of laser diffraction analyzers include the MicrotracMT3300EXII manufactured by Microtrac-Bell, and examples of dynamic light scattering analyzers include the Nanotrac Wave II UT151 manufactured by Microtrac-Bell.

[0060] (F) High boiling point solvent The alkali-developable resin composition of the present invention achieves the above-mentioned object of the present invention by using, as the main component, a high-boiling point solvent having a boiling point higher than that of common solvents.

[0061] In detail, as a result of intensive research, the inventors have found that, in an alkali-developable resin composition, if a carboxyl group-containing vinyl ester resin (B) with a low VOC content is used as is and the VOC content is reduced to 20% or less, the viscosity of the composition increases and bubbles tend to form, resulting in poor appearance of the print, while if the boiling point of the solvent is too high (greater than 280°C), evaporation becomes difficult and a large amount remains after pre-baking, resulting in poor tack-drying of the resin layer.

[0062] By using a high-boiling solvent within a specific boiling point range, namely above 250°C and below 280°C, alkali-developable resin compositions reduce bubbles during printing, improving appearance defects such as pits and pinholes in the coating film, ensuring the ink performance of the alkali-developable resin composition, while significantly reducing the environmental impact due to its low volatility. Furthermore, the composition unexpectedly further improves adhesion and crack resistance during thermal cycling. Excellent crack resistance during thermal cycling indicates that the structure of each part of the cured product is nearly uniform, making it less likely to experience stress differences due to thermal expansion and cooling contraction, and also indicates excellent mechanical properties such as hardness.

[0063] Such high-boiling point solvents may be, for example, one or more selected from polyol ethers, polyol esters, organic acid alkyl esters (esters obtained by reacting an organic acid with a monohydric alcohol), and aliphatic hydrocarbons. Among them, from the viewpoint of more easily achieving the object of the present invention, polyol ethers and polyol esters are preferred, and polyol ethers are more preferred. These high-boiling point solvents may be used alone or in combination of two or more.

[0064] 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).

[0065] The content of the high-boiling point solvent is 40 to 80 parts by mass, more preferably 45 to 75 parts by mass, and even more preferably 50 to 70 parts by mass, relative to 100 parts by mass of the carboxyl group-containing vinyl ester resin (B), calculated as solids content. It is most preferably 60 to 70 parts by mass. If the content is too low, the ink performance will be poor, the adhesion of the cured film will be reduced, and crack resistance during thermal cycling will also be poor. If the content is too high, the tack-drying property will tend to deteriorate. By using a high-boiling point solvent within the above content range, the alkali-developable resin composition will have excellent ink performance while reducing the VOC content. It will be less likely to generate bubbles when printing on thick copper plates and will have better leveling properties. The cured product will have an excellent appearance and further improved adhesion and crack resistance.

[0066] Other solvents In the present invention, for general purposes such as preparing each component system of the alkali-developable resin composition or adjusting its viscosity, a solvent other than the above-mentioned high-boiling point solvent may be used in at least one component system.

[0067] As the solvent other than the high-boiling point solvent, a general organic solvent can be used. Examples of such a solvent 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 (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-based solvents such as petroleum ether, petroleum naphtha, solvent naphtha, and heavy aromatic solvent naphtha.

[0068] These common organic solvents can be used alone or in combination of two or more.

[0069] The content of a common solvent in the base composition of the alkali-developable resin composition of the present invention is preferably in the range of 1 to 40 parts by mass, more preferably 10 to 25 parts by mass, relative to 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) in terms of solids content. The content of a common solvent in the curing agent composition of the alkali-developable resin composition of the present invention is preferably in the range of 2 to 35 parts by mass, more preferably 4 to 25 parts by mass, relative to 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) in terms of solids content.

[0070] Other ingredients In the alkali-developable resin composition of the present invention, it is of course possible to incorporate further additives as other components, if necessary, within the scope of the object of the present invention.

[0071] Examples of such components include colorants such as pigments and dyes, thermal polymerization inhibitors, heat curing catalysts, ultraviolet absorbers, plasticizers, flame retardants, antistatic agents, antioxidants, thixotropic agents, antiaging agents, antibacterial and antifungal agents, antifoaming agents, leveling agents, anti-sagging agents, thickeners, adhesion imparting agents, thixotropy imparting agents, photoinitiator assistants, sensitizers, photobase generators, thermoplastic resins, elastomers, organic fillers, release agents, surface treatment agents, dispersants, dispersion assistants, surface modifiers, stabilizers, fluorescent materials, cellulose resins, and the like.

[0072] Among these, the addition of melamine is preferred. As an antioxidant, it inhibits oxidation of the conductor (copper) on the substrate, improving adhesion between the substrate and the cured film of the alkali-developable resin composition. As a thermosetting catalyst, it promotes the reaction between epoxy groups and carboxyl groups. This can improve properties such as acid resistance, alkali resistance, metal plating resistance, adhesion, and hardness of dry films and cured products formed from the alkali-developable resin composition.

[0073] At least one of the base composition and the curing agent composition of the alkali-developable resin composition of the present invention may optionally contain melamine. To more easily achieve the above-described effects, it is more preferable to add melamine to the curing agent composition. The amount of melamine added is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, based on 100 parts by mass of the (B) carboxyl group-containing vinyl ester resin, calculated as solid content.

[0074] The base composition and the 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 using, for example, a three-roll mill.

[0075] Dry Film A dry film can be produced from the alkali-developable resin composition of the present invention. The dry film of the present invention has a resin layer obtained by coating and drying the alkali-developable resin composition of the present invention on a carrier film. To form the dry film, first, in the case of a two-component system, the base composition and the curing agent composition are thoroughly mixed to obtain the alkali-developable resin composition of the present invention. This composition is then applied to a carrier film in 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, either directly or after diluting with a high-boiling point solvent as necessary to adjust the viscosity. The applied composition is then typically dried at a temperature of 50 to 130°C for 1 to 30 minutes to form a resin layer. There are no particular limitations on the coating thickness, but it is generally selected appropriately within the range of 10 to 150 μm, preferably 20 to 60 μm, after drying.

[0076] As the carrier film, a plastic film is used, and examples thereof include polyester films such as polyethylene terephthalate (PET), polyimide films, polyamideimide films, polypropylene films, polystyrene films, etc. 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.

[0077] After forming a resin layer made of the alkali-developable resin 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. Examples of the peelable cover film that can be used include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper. The cover film may be any material as long as the adhesive strength between the resin layer and the carrier film is smaller than that between the resin layer and the carrier film when the cover film is peeled off.

[0078] In the present invention, the alkali-developable resin 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.

[0079] Here, the alkali-developable resin composition of the present invention can also be used to form a tack-free resin layer by, for example, adjusting the viscosity to a level suitable for the coating method using a high-boiling point solvent, applying the composition to a substrate by a method such as dip coating, flow coating, roll coating, bar coating, screen printing, or curtain coating, and then evaporating and drying (pre-drying) the high-boiling point solvent contained in the composition at a temperature of about 60 to 100° C. Alternatively, in the case of a dry film obtained by applying the composition to a carrier film, drying it, and winding it up as a film, the resin layer can be formed on the surface of the substrate by laminating it onto the substrate using a laminator or the like so that the resin layer is in contact with the substrate, and then peeling off the carrier film.

[0080] The substrates include printed wiring boards and flexible printed wiring boards on which circuits are pre-formed using copper or the like, as well as 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, copper-clad laminates for high-frequency circuits made from fluororesin, polyethylene, polyphenylene ether, polyphenylene oxide, cyanate, etc., and examples include copper-clad laminates of all grades (FR-4, etc.), metal substrates, polyimide film, PET film, polyethylene naphthalate (PEN) film, glass substrates, ceramic substrates, wafer plates, etc.

[0081] cured product To form a cured product using the alkali-developable resin 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 (irradiated 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% aqueous solution of sodium carbonate). The alkali-developable resin composition of the present invention has excellent photosensitivity because it can form a cured film pattern after exposure and development. Furthermore, by heating to a temperature of approximately 100 to 180°C for thermal curing (post-cure), a cured film (cured product) with excellent properties such as heat resistance, chemical resistance, moisture absorption resistance, adhesion, and electrical properties can be formed.

[0082] The volatilization drying or thermal curing when forming the cured product can be carried out using, for example, a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, etc. (a method in which hot air in a dryer equipped with a heat source of an air heating type using steam is brought into countercurrent contact with the substrate, or a method in which hot air is blown onto the substrate from a nozzle).

[0083] 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 ultraviolet 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:

[0084] Next, in the development step, the resin layer after the exposure step is treated with a developer, thereby removing the unexposed portions of the coating film and forming a patterned film of the alkali-developable resin composition of the present invention.

[0085] Here, the developing step can be performed using a dipping method, a shower method, a spray method, a brush method, etc. As the developer, an aqueous sodium carbonate solution having a mass concentration of 0.5 to 5% can usually be used, but other alkaline aqueous solutions such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium silicate, ammonia, and amines can also be used.

[0086] In this development step, the temperature of the developer is 20 to 40° C., and the development time is within 180 seconds.

[0087] In this developing step, the resulting pattern film is washed with a rinse liquid, if necessary. As the rinse liquid, distilled water, methanol, ethanol, isopropyl alcohol, etc. can be used alone or in combination.

[0088] Electronic Components The present invention can also provide an electronic component having the above-mentioned cured product.

[0089] The alkali-developable resin composition or dry film of the present invention can be used for protective films for printed wiring boards, semiconductor elements, and the like, electrical insulating layers, sealing materials for sealing or incorporating electronic components, component-embedding layers, adhesive layers for fixing electronic components, and is particularly suitable for high-density wiring that requires a low dielectric constant and a low dielectric dissipation factor, electronic components that process high-frequency signals, and electronic components for vehicles and robots that require high-temperature and long-term reliability.

[0090] 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.

[0091] 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.

[0092] Unless otherwise specified, the "parts" and "%" shown are based on mass. Example

[0093] [Synthesis example: Synthesis of carboxyl group-containing vinyl ester resin] 600 g of diethylene glycol dibutyl ether was charged with 1070 g of o-cresol novolac epoxy resin (DIC Corporation, EPICLONN-695, softening point 95°C, epoxy equivalent 214, average functionality 7.6) (number of glycidyl groups (total number of aromatic rings): 5.0 mol), 360 g (5.0 mol) of acrylic acid, and 1.5 g of hydroquinone. The mixture was heated to 100°C, stirred, and dissolved uniformly. Next, 4.3 g of triphenylphosphine was charged, heated to 110°C, and reacted for 2 hours, then heated to 120°C and reacted for an additional 12 hours. 415 g of diethylene glycol dibutyl ether and 456.0 g (3.0 mol) of tetrahydrophthalic anhydride were charged to the resulting reaction solution, reacted at 110°C for 4 hours, and then cooled to obtain a carboxyl group-containing vinyl ester resin (varnish). The solids concentration of the carboxyl group-containing vinyl ester resin (varnish) thus obtained was 65% by mass, and the acid value of the solids was 89 mgKOH / g. The weight-average molecular weight (Mw) of the carboxyl group-containing vinyl ester resin thus obtained was 9,000. The weight-average molecular weight of the resin thus obtained was measured by high-performance liquid chromatography using a pump LC-6AD manufactured by Shimadzu Corporation and three columns, Shodex (registered trademark) KF-804, KF-803, and KF-802 manufactured by Showa Denko K.K.

[0094] [Examples 1 to 6 and Comparative Examples 1 to 5] The components shown in Table 1 were mixed in advance in a mixer in the respective amounts, and then kneaded in a three-roll mill to prepare alkali-developable resin compositions (two-component systems consisting of a base composition and a curing agent composition) of Examples 1 to 6 and Comparative Examples 1 to 5, respectively.

[0095] [Table 1]

[0096] Each component listed in Table 1 is explained as follows: *1: Carboxyl group-containing vinyl ester resin obtained in the synthesis example, solid content 65%, solvent component (carbitol acetate (general solvent)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd. *2: Carboxyl group-containing vinyl ester resin obtained in the synthesis example (only the solvent component is changed), solid content 65%, solvent component (diethylene glycol dibutyl ether ((F) high boiling point solvent *20)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd. *3: Carboxyl group-containing vinyl ester resin obtained in the synthesis example (only the solvent component is changed), solid content 65%, solvent component (2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB) (high boiling point solvent *21)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd. *4: Carboxyl group-containing vinyl ester resin obtained in the synthesis example (only the solvent component is changed), solid content 65%, solvent component (diethylene glycol butyl ether acetate (general organic solvent *22)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd. *5: Carboxyl group-containing vinyl ester resin obtained in the synthesis example (only the solvent component is changed), solid content 65%, solvent component (tripropylene glycol n-butyl ether ((F) high boiling point solvent *23)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd. *6: Carboxyl group-containing vinyl ester resin obtained in the synthesis example (only the solvent component is changed), solid content 65%, solvent component (tetraethylene glycol dimethyl ether ((F) high boiling point solvent *24)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd. Differences between *1 to *6: The only difference between the six resins is the type of solvent. The solvent content is all 35% and the solid content is the same, with the solid content being 65%. *7: Organic bentonite: thixotropic agent, ORBEN M, manufactured by Shiraishi Calcium (Shanghai) International Trading Co., Ltd. *8: Green pigment paste: 6Y-501 base product, manufactured by Toyo Color Co., Ltd. *9: Antioxidant: IRGANOX 1010, manufactured by BASF Japan *10: Antifoaming agent: KSZ-118, manufactured by Zhejiang Shin-Etsu Seisei Kako Co., Ltd. *11: Leveling agent: BYK-1790, manufactured by BYK (Shanghai) Co., Ltd. *12: Photopolymerization initiator: ITX, isopropylthioxanthone (manufactured by DKSH Japan) *13: Photopolymerization initiator: #907: α-aminoacetophenone-based photopolymerization initiator (Omnirad 907, manufactured by IGM Resins) (2-methyl-1-(4-methylthiophenyl)-2-morpholinylpropan-1-one) *14: Filler: HD25, talc, manufactured by Toishi (Shanghai) Trading Co., Ltd. *15: Filler: A2, barium sulfate, manufactured by Foshan Anyi Nano Materials Co., Ltd. *16: Antifoaming agent: DS-100, manufactured by Nankai Oda Chemical Co., Ltd., Foshan City *17: Anti-sagging agent: BYK-R606, manufactured by BYK (Shanghai) Co., Ltd. *18: Common organic solvent: DPM, dipropylene glycol monomethyl ether, manufactured by Shanghai Hongze Chemical Co., Ltd. (boiling point 190°C) *19: Common organic solvent: S-150, heavy aromatic solvent naphtha, manufactured by Shanghai Hongze Chemical Co., Ltd. (boiling point 180°C) *20: (F) High boiling point organic solvent: Diethylene glycol dibutyl ether, manufactured by Anhui Lixing New Materials Co., Ltd. (boiling point 254°C) *21: High boiling point organic solvent: TXIB, manufactured by Wuhan Qiaofeng Chemical Co., Ltd. (boiling point 281℃) *22: Common organic solvent: Diethylene glycol butyl ether acetate, manufactured by Guangzhou Inda New Materials Co., Ltd. (boiling point 245°C) *23: (F) High-boiling organic solvent: Tripropylene glycol n-butyl ether, manufactured by Dow Chemical (Shanghai) Co., Ltd. (boiling point 275 °C) *24: (F) High-boiling organic solvent: Tetraethylene glycol dimethyl ether, manufactured by Jinan Mingwei Chemical Co., Ltd. (boiling point 275 °C) *25: Epoxy resin: 128E, manufactured by Nan Ya Plastics Corporation, bisphenol A type epoxy resin (solid content 100%) *26: Epoxy resin: BNE200D75, bisphenol A novolac type epoxy resin, manufactured by Shanghai Hongze Chemical Co., Ltd. *27: Epoxy resin: N-770-75EA, manufactured by DIC Corporation, novolac type polyfunctional epoxy resin, solid content 75% *28: Epoxy resin: TGIC-G, manufactured by Shanghai Xindi Chemical Co., Ltd. *29: Photosensitive monomer: DPHA, dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd. *30: Melamine: MELAMINE-JC, manufactured by Shanghai Xindi Chemical Co., Ltd. *31: General organic solvent: DPM, dipropylene glycol monomethyl ether, manufactured by Shanghai Hongze Chemical Co., Ltd. <9000401><9000402>For the obtained main agent compositions, curing agent compositions of the examples and comparative examples, and alkali-developable resin compositions obtained by mixing these, the following tests were conducted.

[0098] <VOCs content> In accordance with GB / T 38608-2020, when the predicted VOC content (mass fraction) in the alkali-developable resin composition exceeds 15%, it was measured using the difference method, and when the predicted VOC content (mass fraction) in the alkali-developable resin composition is 15% or less, it was measured using gas chromatography.

[0099] <Bubbles during printing> The alkali-developable resin compositions of the above Examples and Comparative Examples were applied to the entire surface of a copper-clad laminate having an opening pattern with a diameter of 400 μm and a pitch of 600 μm and a copper thickness of 3 oz (105 μm) by screen printing, allowed to stand at room temperature for 30 minutes, and then dried at 80°C for 30 minutes in a hot air circulation drying oven to produce a substrate for evaluating defoaming properties. The substrate for evaluating defoaming properties was observed using a 100-fold optical microscope, and it was confirmed whether or not bubbles were generated in the resin layer filled in the opening pattern portion. The number (unit number) of the opening pattern portions where bubbles were generated was counted, and the bubble generation rate in the copper opening pattern portion was evaluated. The evaluation criteria are as follows. The smaller the bubble generation rate, the better the appearance of the cured film. 〇: The bubble generation rate is less than 50%. △: The bubble generation rate is 50% or more. Bubble generation rate (%) = (number of unit portions where bubbles exist / total 100 unit portions) × 100%

[0100] <Touch dryness> Each of the alkali-developable resin compositions of the above Examples and Comparative Examples was applied to the entire surface of a copper-clad laminate polished with a polishing roller by screen printing, dried at 80°C for 30 minutes to produce a substrate having a resin layer, and the touch dryness of the surface of the resin layer was evaluated. ○: It is not sticky at all. △: It is slightly sticky. ×: It is sticky.

[0101] <Wetting tension (print adhesion force) of the cured film surface> The alkali-developable resin compositions of the Examples and Comparative Examples were each applied to the entire surface of a copper foil laminate by screen printing so as to have a thickness of 20 μm, and dried at 80°C for 30 minutes in a hot air circulation drying oven. After cooling to room temperature, the entire surface was exposed at 400 mJ / cm <00,00003>using an exposure apparatus equipped with a high-pressure mercury lamp. Next, after developing in a 1 wt% aqueous sodium carbonate solution at a pressure of 0.2 MPa and a liquid temperature of 30°C for 60 seconds, it was cured at 150°C for 60 minutes in a hot air circulation drying oven to produce an evaluation substrate having a cured film. Next, the surface tension of the cured film of the evaluation substrate was measured using a standard dye pen. The larger the value of the surface tension, the better the hydrophilicity and the more advantageous for the adhesion of letters.

[0102] <Adhesion> The alkali-developable resin compositions of the Examples and Comparative Examples were each applied to the entire surface of a copper foil laminate by screen printing to a thickness of 20 μm, and then dried in a hot air circulating drying oven at 80° C. for 30 minutes. After cooling to room temperature, the resin compositions were exposed to 400 mJ / cm using an exposure device equipped with a high-pressure mercury lamp. 2 The entire surface was exposed to UV light. Next, the substrate was developed in a 1 wt% aqueous sodium carbonate solution at a pressure of 0.2 MPa and a liquid temperature of 30°C for 60 seconds, and then cured in a hot air circulating drying oven at 150°C for 60 minutes. These substrates were then exposed to UV light at 2000 mJ / cm using a UV conveyor oven. 2 The coated substrate was irradiated with ultraviolet light at 1000 kJ / cm 2 at 100 kJ / cm 2 to prepare a substrate for evaluating adhesion having a cured film. Using a cutter guide, 100 grid patterns with sides of 1 mm were drawn on the cured film of the evaluation substrate, and a peeling test was carried out once using transparent tape (3 m, width 24 mm, adhesive strength 1.8 N / 10 mm or more) to confirm the rate at which the 1 mm grid patterns fell off. 〇: No dropout △: Dropout is 1% or less ×: Dropout exceeds 1%

[0103] <Crack resistance> The alkali-developable resin compositions of the Examples and Comparative Examples were applied by screen printing to a thickness of 40 μm over the entire surface of a substrate on which a 2 mm copper wire pattern had been formed, and then dried at 80°C for 30 minutes using a hot air circulation dryer. After cooling to room temperature, the resin compositions were exposed to 400 mJ / cm using an exposure device equipped with a high-pressure mercury lamp. 2 The pattern was exposed to light with a UV lamp, and then developed in a 1 wt% aqueous solution of sodium carbonate at a pressure of 0.2 MPa and a liquid temperature of 30°C for 60 seconds, and then cured in a hot air circulating drying oven at 150°C for 60 minutes. The cumulative exposure in the UV conveyor oven was 2000 mJ / cm. 2A substrate for evaluating crack resistance in thermal cycles was prepared by irradiating the substrate with ultraviolet light at 1000 kJ / s at 1000 kJ / s, forming 17 patterns of cured film with right-angled shapes. The evaluation substrates prepared as described above were placed in a thermal cycler that cycled temperatures between -40°C and 140°C, and a thermal shock resistance cycle test (TCT test) was conducted by setting different numbers of cycles. The appearance was then observed after each number of cycles, and the maximum number of cycles at which no cracks occurred in the cured film was recorded (see Figures 1 and 2 for the presence or absence of cracks). The evaluation criteria were as follows: ○: No cracks occur after 500 or more cycles ×: Cracks occurred after less than 500 cycles

[0104] The results shown in Table 1 demonstrate that the alkali-developable resin composition of the present invention has a reduced VOC content, excellent ink performance, is less likely to generate bubbles when printing on thick copper plates, has better leveling properties, and produces cured products with excellent appearance, as well as improved adhesion and crack resistance.

[0105] On the other hand, the base compositions of Comparative Examples 1 and 2 contained common solvents but did not contain high-boiling-point solvents, so the VOC content exceeded the standard, there were many bubbles during printing, and although the coating surface had excellent tack-dryness, the coating surface had low wetting tension (low letter adhesion), poor adhesion, and poor crack resistance during thermal cycling.

[0106] Comparative Example 3 mainly contained common solvents but also contained some high-boiling point solvents, and although the VOC content was reduced, there were many bubbles during printing, the wetting tension of the coating surface was low (low letter adhesion), adhesion was poor, and crack resistance during thermal cycling was poor. Dryness to the touch was also poor.

[0107] The base composition of Comparative Example 4 contained the high-boiling point solvent TXIB (boiling point 281°C), and the VOC content was significantly reduced, there were fewer bubbles during printing, and the wetting tension of the coating surface was slightly improved, but the tack-drying property was reduced, adhesion was poor, and crack resistance during thermal cycling was poor.

[0108] The base composition of Comparative Example 5 contained the common solvent diethylene glycol butyl ether acetate (boiling point 245°C), which reduced the VOC content, reduced bubbles during printing, and slightly improved the wetting tension of the coating surface, but reduced tack-dryness, poor adhesion, and poor crack resistance during thermal cycling.

[0109] In contrast, the alkali-developable resin compositions of the examples not only had significantly lower VOC contents (reaching 10% or less), but also produced fewer bubbles during printing, improved wetting tension on the surface of the cured film, excellent tactile dryness, high adhesion of the cured film, and excellent crack resistance during thermal cycling. Thus, the alkali-developable resin compositions of the present invention are less harmful to the environment and have better ink performance, while at the same time, the appearance, character adhesion, adhesion, and crack resistance of the cured film formed are further improved, making them particularly suitable for use in cured products for printed wiring boards, such as solder resists, which are produced using photolithography, and for electronic components incorporating such cured products.

Claims

1. An alkali-developable resin composition comprising at least a two-component resin composition, The alkali-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, and (F) a high-boiling point solvent; the (B) carboxyl group-containing vinyl ester resin, the (C) photopolymerization initiator, the (E) inorganic filler, and the (F) high-boiling point solvent are contained in a resin composition different from that of the (A) epoxy resin and the (D) photosensitive monomer, The alkali-developable resin composition, wherein the boiling point of the (F) high-boiling-point solvent is higher than 250°C and not higher than 280°C.

2. 2. The alkali-developable resin composition according to claim 1, wherein the high-boiling point solvent (F) is at least one solvent selected from the group consisting of polyol ethers, polyol esters, organic acid alkyl esters, and aliphatic hydrocarbons.

3. 3. The alkali-developable resin composition according to claim 1, wherein the (F) high-boiling point solvent is at least one or more selected from the group consisting of diethylene glycol dibutyl ether, tripropylene glycol n-butyl ether, tetraethylene glycol dimethyl ether, and tripropylene glycol dibutyl ether.

4. 3. The alkali-developable resin composition according to claim 1, wherein a content of the (F) high-boiling point solvent is 40 to 80 parts by mass, calculated as a solid content, relative to 100 parts by mass of the (B) carboxyl group-containing vinyl ester resin.

5. 3. The alkali-developable resin composition according to claim 1, wherein at least one component of the at least two-component system further contains a solvent other than the high-boiling point solvent (F).

6. 3. The alkali-developable resin composition according to claim 1, wherein the content of volatile organic compounds is 10% or less by mass fraction.

7. A dry film having a resin layer obtained by applying the alkali-developable resin composition according to any one of claims 1 to 6 to a carrier film and drying the applied resin composition.

8. A cured product obtained by curing the alkali-developable resin composition according to any one of claims 1 to 6.

9. A cured product obtained by curing the resin layer of the dry film according to claim 7.

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

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