Melamine-free alkali-developable resin composition, dry film, cured product, and electronic component having the cured product.

Abstract

The present invention provides a melamine-free alkali-developable resin composition, dry film, cured product, and electronic component having the cured product, which exhibits excellent pencil hardness, acid resistance, metal plating resistance, alkali resistance, and solvent resistance, as well as excellent drying control range, sensitivity, and resolution. The composition contains an epoxy resin, a carboxyl group-containing vinyl ester resin, a photopolymerization initiator, a photosensitive monomer, an inorganic filler, and a hydroxyl group-containing compound component, wherein the carboxyl group-containing vinyl ester resin and the inorganic filler, and the epoxy resin and the photosensitive monomer are each contained in different resin compositions, the pH value of the hydroxyl group-containing compound component is 4.0 or higher and 5.5 or lower, the hydroxyl group-containing compound component contains a hydroxyl group-containing compound having at least one hydroxyl group in its molecule, and the content of the hydroxyl group-containing compound component is 1.2 to 7.8 parts by mass per 100 parts by mass of the carboxyl group-containing vinyl ester resin on a solid content basis.

Description

[Technical Field]

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

[0002] In the manufacturing of printed circuit boards, curable resin compositions are typically used to form permanent coatings such as solder resist layers. Dry film and liquid compositions have been developed as examples of such curable resin compositions. Furthermore, to enable miniaturization of electronic components, high-precision design structures, and complex manufacturing methods, it is anticipated that the principles of photolithography will be applied to pattern curable resin compositions, thereby enabling microfabrication. In recent years, from an environmental perspective, alkaline-developable types that can be developed with dilute, weakly alkaline aqueous solutions have become the mainstream.

[0003] Until now, solder resist (also called solder resist ink) has been used in printed circuit boards as a protective material for the circuits on the board. Currently, in the actual manufacturing of printed circuit boards, alkali-developable photosensitive compositions are commonly used as solder resist. The mainstream method for forming the solder resist layer using this is contact exposure, in which the solder resist composition is applied to the substrate on which the circuits are formed, dried, and then exposed to light by vacuum-fitting a photomask.

[0004] Currently available solder resist inks typically contain melamine, which acts as both a thermosetting agent and an antioxidant, improving the ink's properties such as acid resistance, alkali resistance, metal plating resistance, adhesion, and hardness. However, melamine in the ink has several problems, including the fact that it volatilizes during the welding process (260°C) and that, according to the European Union's REACH Regulation (Registration, Evaluation, Authorisation and Restriction of Chemicals), it is an environmentally regulated substance that would be added to the SVHC (Substances of Very High Concern) list.

[0005] Patent Document 1 describes the production of a highly sensitive epoxy solder-resist acrylic oligomer containing hydroxyl groups, carboxyl groups, and double bonds, with acid value and epoxy equivalent within a specific range, thereby improving the sensitivity of solder-resist inks. However, when manufacturing inks using the above epoxy solder-resist acrylic oligomer, conventional curing agents continue to be used. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] CN114262424A [Overview of the project] [Problems that the invention aims to solve]

[0007] Traditionally, solder resist inks have commonly contained melamine as a thermosetting agent and antioxidant. However, with increasing environmental concerns, there is a growing demand for the manufacture of alkali-developable resin compositions that do not use melamine, possess excellent drying control range, sensitivity, and resolution, and whose cured products exhibit excellent pencil hardness, acid resistance, metal plating resistance, alkali resistance, and solvent resistance.

[0008] Therefore, the object of the present invention is to provide an alkali-developable resin composition whose cured product has excellent pencil hardness, acid resistance, metal plating resistance, alkali resistance, and solvent resistance, and which also has excellent drying control range, sensitivity, and resolution.

[0009] A further object of the present invention is to provide a dry film and a cured product having excellent properties as described above, obtained using such an alkali-developable solder resist composition, as well as a printed circuit board having a cured film such as solder resist formed on it. [Means for solving the problem]

[0010] As a result of diligent research, the present inventors have found an alkali-developable resin composition comprising at least a two-component resin composition, containing an epoxy resin, a carboxyl group-containing vinyl ester resin, a photopolymerization initiator, a photosensitive monomer, an inorganic filler, and a hydroxyl group-containing compound component. The carboxyl group-containing vinyl ester resin and the inorganic filler, and the epoxy resin and the photosensitive monomer are each contained in different resin compositions. We have found that the above problem can be solved by an alkali-developable resin composition characterized in that the pH value of the hydroxyl group-containing compound component is 4.0 or higher and 5.5 or lower, the hydroxyl group-containing compound component contains a hydroxyl group-containing compound having at least one hydroxyl group in its molecule, and the content of the hydroxyl group-containing compound component is 1.2 to 7.8 parts by mass per 100 parts by mass of the carboxyl group-containing vinyl ester resin on a solid content basis.

[0011] A preferred embodiment of the present invention relates to an alkali-developable resin composition characterized in that the hydroxyl group-containing compound having at least one hydroxyl group in the molecule is at least one or more selected from the group consisting of alcohols, phenols, ethers, esters, or polymers.

[0012] A more preferred aspect of the present invention relates to an alkali-developable resin composition characterized in that the hydroxyl group-containing compound having at least one hydroxyl group in the molecule is a polymer having hydroxyl groups in its side chain and / or terminal, for example, a propylene glycol compound and / or a propylene glycol ether compound.

[0013] A more preferred aspect of the present invention relates to an alkali-developable resin composition characterized in that the acid value of the hydroxyl group-containing compound component having at least one hydroxyl group in the molecule is 10 to 100 mg KOH / g.

[0014] Furthermore, a particularly preferred aspect of the present invention relates to an alkali-developable resin composition characterized in that the number average molecular weight of the hydroxyl group-containing compound having at least one hydroxyl group in the molecule is in the range of 500 to 5000.

[0015] Furthermore, particularly preferred embodiments of the present invention relate to an alkali-developable resin composition characterized in that the carboxyl group-containing vinyl ester resin, the photopolymerization initiator, the inorganic filler, and the hydroxyl group-containing compound component are each contained in different resin compositions from the epoxy resin and the photosensitive monomer.

[0016] Another aspect of the present invention relates to a dry film having a resin layer obtained by coating and drying the above-mentioned alkali-developable resin composition onto a carrier film.

[0017] Yet another aspect of the present invention relates to the alkali-developable resin composition described above, characterized in that it is used as a material for solder resist.

[0018] Further aspects of the present invention relate to cured products obtained by curing an alkali-developable resin composition, cured products obtained by curing a resin layer of a dry film, and electronic components having these cured products. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide an alkali-developable resin composition whose cured product has excellent pencil hardness, acid resistance, metal plating resistance, alkali resistance, and solvent resistance, and is excellent in any of the drying control range, sensitivity, and resolution.

[0020] Furthermore, according to the present invention, it is possible to provide a dry film and a cured product excellent in the above-mentioned respective characteristics obtained by using such an alkali-developable resin composition, and an electronic component such as a printed wiring board formed by forming a cured film such as a solder resist as the cured product.

Embodiments for Carrying Out the Invention

[0021] The alkali-developable resin composition of the present invention preferably consists of at least a two-component resin composition. For example, a two-component system in which one resin composition is used as the main agent composition and another resin composition is used as the curing agent composition can be mentioned. In this case, for example, a carboxyl group-containing vinyl ester resin and an inorganic filler, and an epoxy resin and a photosensitive monomer are contained in different resin compositions, respectively. The main agent composition preferably consists of at least a carboxyl group-containing vinyl ester resin, a photopolymerization initiator, an inorganic filler, and a hydroxyl group-containing compound component, and the curing agent composition preferably consists of at least an epoxy resin and a photosensitive monomer.

[0022] At this time, from the viewpoint of preventing chemical reactions during the storage period, it is preferable that the epoxy resin and the carboxyl group-containing vinyl ester resin are contained in different compositions from each other, and the photosensitive monomer and the photopolymerization initiator are contained in different compositions from each other.

[0023] Hereinafter, each component constituting the alkali-developable resin composition of the present invention will be described.

[0024] epoxy resin The epoxy resin functions as a thermosetting component in the alkali-developable resin composition and forms a cured product.

[0025] As such epoxy resins, known and conventional polyfunctional epoxy resins having at least two epoxy groups in one molecule can be used.

[0026] The epoxy resin may be liquid at room temperature, or it may be solid or semi-solid.

[0027] Preferred polyfunctional epoxy resins include, but are not limited to, bisphenol A type epoxy resins, brominated epoxy resins, novolac type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, glycidylamine type epoxy resins, hydantoin type epoxy resins, alicyclic epoxy resins, trihydroxyphenylmethane type epoxy resins, bixylenol type or biphenol type epoxy resins or mixtures thereof, bisphenol S type epoxy resins, bisphenol A novolac type epoxy resins, tetraphenyloleethane type epoxy resins, heterocyclic epoxy resins, diglycidyl phthalate resins, tetraglycidyl xylenoylethane resins, naphthalene group-containing epoxy resins, epoxy resins having a dicyclopentadiene skeleton, glycidyl methacrylate copolymer epoxy resins, copolymer epoxy resins of cyclohexylmaleimide and glycidyl methacrylate, epoxy-modified polybutadiene rubber derivatives, CTBN-modified epoxy resins, and epoxy resins having an isocyanuric ring.

[0028] These epoxy resins can be used individually or in combination of two or more types.

[0029] "Epoxy resins that are solid or semi-solid at room temperature" can also be those that are known and commonly used. For example, epoxy resins that are solid at room temperature include bisphenol A type epoxy resin (JER1001, manufactured by Mitsubishi Chemical Corporation), bisphenol F type epoxy resin (JER4004P, manufactured by Mitsubishi Chemical Corporation), naphthalene type epoxy resin (HP-4700, manufactured by DIC Corporation), naphthalene skeleton-containing polyfunctional solid epoxy resin (NC-7000, manufactured by Nippon Kayaku Co., Ltd.), trisphenol epoxy resin (EPPN-502H, manufactured by Nippon Kayaku Co., Ltd.), dicyclopentadiene skeleton-containing polyfunctional solid epoxy resin (Epiclon HP-7200, manufactured by DIC Corporation), phosphorus-containing epoxy resin (TX0712, manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), and tris(2,3-epoxypropyl) isocyanurate (TEPIC, manufactured by Nissan Chemical Industries, Ltd.). As for epoxy resins that are semi-solid at room temperature, there is bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation). Examples include jER834), naphthalene-type epoxy resin (HP-4032 manufactured by DIC Corporation), etc.

[0030] Here, in this invention, "solid or semi-solid at room temperature" means that the substance is solid or semi-solid at 15°C. The determination of whether a substance is solid or semi-solid can be made in accordance with the "Method for confirming liquid status" in Appendix 2 of the Ministerial Ordinance Concerning the Testing and Properties of Hazardous Materials (Ministry of Home Affairs Ordinance No. 1 of 1989).

[0031] As biphenyl-type epoxy resins, known and conventional polyfunctional epoxy resins having a biphenyl skeleton can be used. Examples include biphenyl skeleton-containing polyfunctional solid epoxy resins (NC-3000H, NC-3000, manufactured by Nippon Kayaku Co., Ltd.) and biphenyl-type epoxy resins (YX-4000, YL-6121HA, manufactured by Mitsubishi Chemical Corporation).

[0032] Examples of novolac-type epoxy resins include cresol novolac-type epoxy resin (Epiclon N-690, manufactured by DIC Corporation) and phenol novolac-type epoxy resins (Epiclon N-770, manufactured by DIC Corporation, and jER152, manufactured by Mitsubishi Chemical Corporation).

[0033] The epoxy resin content described above is preferably in the range of approximately 30 to 100 parts by mass, more preferably in the range of 40 to 90 parts by mass, and even more preferably in the range of 50 to 85 parts by mass, based on solid content, per 100 parts by mass of carboxyl group-containing vinyl ester resin.

[0034] Carboxyl group-containing vinyl ester resin In the present invention, carboxyl group-containing vinyl ester resins that contain ethylenically unsaturated double bonds in their molecules are particularly preferred from the viewpoint of providing alkali developability, photocurability, and developability. Examples include resins starting from epoxy resins, polyurethane resins having a urethane skeleton, copolymer resins having a copolymer structure of unsaturated carboxylic acids, and resins starting from phenolic compounds. Specific examples of carboxyl group-containing vinyl ester resins are shown below. (1) A carboxyl group-containing vinyl ester resin obtained by reacting 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 an alcoholic hydroxyl group that reacts with an epoxy group in one molecule, with a saturated or unsaturated polybasic acid anhydride. (2) A carboxyl group-containing resin obtained by reacting a polyfunctional epoxy resin with an unsaturated monocarboxylic acid, followed by a polybasic acid anhydride, and further reacting it with a compound having one oxirane ring and one or more ethylenically unsaturated groups in the molecule, thereby obtaining a carboxyl group-containing vinyl ester resin. (3) A carboxyl group-containing vinyl ester resin obtained by reacting a polyfunctional epoxy resin such as a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, a bisphenol A cresol novolac type epoxy resin, or a dicyclopentadiene cresol novolac type 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 chain. (4) A carboxyl group-containing vinyl ester resin obtained by reacting a polyfunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of the polyfunctional epoxy resin of (3) above with epichlorohydrin with (meth)acrylic acid, and adding a polybasic acid anhydride to the resulting hydroxyl groups. (5) 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 novolac resin, partially esterifying the resulting hydroxyl group with (meth)acrylic acid, and reacting the remaining hydroxyl group with a polybasic acid anhydride. (6) A carboxyl group-containing vinyl ester resin obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in its molecule, such as glycidyl (meth)acrylate or α-methylglycidyl (meth)acrylate, to any of the resins in (3) to (5) above. Particularly preferred among these examples are cresol novolac type and phenol novolac type carboxyl group-containing vinyl ester resins, i.e., the carboxyl group-containing vinyl ester resins of (3), (4), (5), and (6) above.

[0035] In this specification, (meth)acrylate is a general term referring to acrylates, methacrylates, and mixtures thereof, and the same applies to other similar expressions.

[0036] The carboxyl group-containing vinyl ester resin described above has numerous free carboxyl groups in the side chains of the main chain polymer, which allows for development with dilute alkaline aqueous solutions.

[0037] Furthermore, the acid value of the carboxyl group-containing vinyl ester resin described above is preferably in the range of 40 to 200 mgKOH / g, and more preferably in the range of 45 to 120 mgKOH / g. If the acid value is less than 40 mgKOH / g, alkaline development becomes difficult. On the other hand, if it exceeds 200 mgKOH / g, the dissolution of the exposed areas by the developer is promoted, resulting in lines that are thinner than necessary, and the exposed and unexposed areas are dissolved and peeled off by the developer without distinction, making it difficult to draw the resist pattern as normal, which is undesirable.

[0038] Furthermore, the mass-average molecular weight of the carboxyl group-containing vinyl ester resin described above varies depending on the resin skeleton, but is generally preferred to be in the range of 2,000 to 150,000, and even more preferably in the range of 5,000 to 100,000. If the mass-average molecular weight is less than 2,000, the tack-free properties (touch-dryness) after coating and drying on the substrate will be poor, and the moisture resistance of the coating film after exposure may deteriorate, the amount of film obtained during development may decrease, and the resolution may be significantly reduced. On the other hand, if the mass-average molecular weight exceeds 150,000, the developability may be significantly poor and the storage stability may deteriorate.

[0039] Photopolymerization initiator Examples of photopolymerization initiators 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-trimethylphenylphosphine oxide. Bisacyl phosphine oxides such as tylpentyl phosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenyl phosphine oxide, bis-(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide; 2,6-dimethoxybenzoyl diphenyl phosphine oxide, 2,6-dichlorobenzoyl diphenyl phosphine oxide, 2,4,6-trimethylbenzoylphenyl phosphate methyl ester, 2-methylbenzoyl diphenyl phosph Monoacyl phosphine oxides such as phenyl oxide, isopropyl pivaloylphenylphosphinate, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; 1-hydroxycyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-hydroxy Hydroxyacetophenones such as -2-methyl-1-phenylpropan-1-one; Benzoins such as benzoin, benzyl, 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, Michlar's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bisdiethylaminobenzophenone;Acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl 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, N,N-dimethylaminoacetophenone, etc.; thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropyl Thioxanthones such as thioxanthone; anthraquinones such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzoic acid esters such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, and p-dimethylbenzoate ethyl ester; oxime esters such as 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyl oxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyl oxime); bis(η; 5 Examples of photopolymerization initiators include titanosenes such as -2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl)titanium and 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.

[0040] The content of the photopolymerization initiator is preferably 5 to 25 parts by mass, and more preferably 8 to 20 parts by mass, per 100 parts by mass of the carboxyl group-containing resin, based on solid content. When the content is 5 parts by mass or more, good surface curability is obtained, and when it is 25 parts by mass or less, halation is less likely to occur and good resolution can be obtained.

[0041] Photosensitive monomer The alkali-developable resin composition capable of forming the cured product of the present invention may contain known and conventional photosensitive monomers. The photosensitive monomer may, for example, be a compound having one or more ethylenically unsaturated groups in its molecule. Such photosensitive monomers (if they contain ethylenically unsaturated groups) assist in the photocuring of carboxyl-containing vinyl ester resins by active energy ray irradiation, thereby curing the alkali-developable resin composition.

[0042] The photosensitive monomers preferably used in the present invention include, for example, methyl α-(allyloxymethyl)acrylate, or 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,Diacrylates of diols 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, diacrylate of diols obtained by adding at least one of ethylene oxide and propylene oxide to neopentyl glycol, diacrylates of glycols such as caprolactone-modified hydroxypivalic acid neopentyl glycol diacrylate, EO adduct diacrylate of bisphenol A, PO adduct diacrylate of bisphenol A, tricyclodecanedimethanol diacrylate, hydrogenated dicyclopentadienyl diacrylate, cyclohexyl diacrylate, and other cyclic diacrylates, or corresponding methacrylate monomers. Examples include polyfunctional acrylates such as methacrylate, 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, or silsesquioxane-modified products thereof, or corresponding methacrylate monomers, trifunctional methacrylate esters, polyfunctional methacrylates such as ε-caprolactone-modified tris(acrooxyethyl) isocyanurate, or combinations of two or more of these.

[0043] The content of such photosensitive monomers is preferably in the range of 5 to 50 parts by mass, more preferably in the range of 10 to 45 parts by mass, and even more preferably in the range of 15 to 40 parts by mass, based on solid content, per 100 parts by mass of carboxyl group-containing vinyl ester resin.

[0044] If the photosensitive monomer content is within this range, the alkali-developable resin composition will have sufficient photocurability, resulting in better patterning during development and good touch-dry properties.

[0045] inorganic fillers In the present invention, the inorganic filler may be used alone or in combination of two or more types.

[0046] The amount of inorganic filler added is preferably in the range of 10 to 100 parts by mass, more preferably in the range of 15 to 80 parts by mass, and even more preferably in the range of 20 to 60 parts by mass, based on solid content, per 100 parts by mass of carboxyl group-containing vinyl ester resin. If the amount of inorganic filler added is 10 parts by mass or more, a cured film with better solder heat resistance, insulation reliability, reflectivity, and heat discoloration resistance tends to be obtained. If the amount of inorganic filler added is 80 parts by mass or less, an alkali-developable resin composition with better defoaming properties, resolution, and deep curing properties tends to be obtained.

[0047] Examples of inorganic fillers include titanium dioxide, silica, barium sulfate, barium titanate, Neuburg silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, and aluminum nitride. Among these, it is preferable to include at least one of talc, silica, and barium sulfate, as this can suppress curing shrinkage of the cured product of the alkali-developable resin composition and improve properties such as adhesion, hardness, and reflectivity.

[0048] From the viewpoint of improving the mechanical properties, heat resistance, processability, and chemical resistance of the cured product, it is preferable that the main component contains an inorganic filler. At least one of silica and barium sulfate is preferred as the inorganic filler.

[0049] The inorganic fillers may be surface-treated, and it is more preferable that their surfaces are surface-treated to allow for the introduction of curable reactive groups.

[0050] Here, a curable reactive group refers to a group that undergoes a curing reaction with epoxy resins or carboxyl group-containing vinyl ester resins, and may be either a photocurable reactive group or a thermosetting reactive group. Examples of photocurable reactive groups include methacrylic groups, acrylic groups, vinyl groups, and styryl groups, while examples of thermosetting reactive groups include epoxy groups, amino groups, hydroxyl groups, carboxyl groups, isocyanate groups, imino groups, oxetanyl groups, mercapto groups, methoxymethyl groups, methoxyethyl groups, ethoxymethyl groups, ethoxyethyl groups, and oxazoline groups.

[0051] The method for introducing curable reactive groups to the surface of an inorganic filler is not particularly limited and can be done using known and conventional methods. The surface of the inorganic filler can be treated with a surface treatment agent having curable reactive groups, such as a coupling agent having curable reactive groups as organic groups. Examples of coupling agents that can be used include silane coupling agents, titanium coupling agents, zirconium coupling agents, and aluminum coupling agents. Examples of surface-treated inorganic fillers that do not have curable reactive groups include those treated with silica-alumina surface treatment, titanate-based coupling agent treatment, aluminate-based coupling agent treatment, and organic treatment.

[0052] The average particle size (D50) of the inorganic filler is preferably 2000 nm or less, and more preferably 1200 nm or less. Furthermore, the lower limit of the average particle size (D50) is preferably 0.1 nm or more.

[0053] The smaller the average particle size of the inorganic filler, the more diffuse reflection is suppressed during light irradiation, making it easier to finely process the cured material pattern. 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 from Microtrac-Bell, and examples of dynamic light scattering analyzers include the Nanotrac Wave II UT151 from Microtrac-Bell.

[0054] Hydroxyl group-containing compound components The alkali-developable resin composition of the present invention achieves the above-described objectives of the present invention by using a hydroxyl group-containing compound component within a specific pH range as the main component.

[0055] In detail, the inventors, through diligent research, found that melamine has the ability to donate electrons, absorb radicals, and play a certain polymerization inhibitory role in the photoinitiated polymerization process, thereby reducing sensitivity. By replacing melamine with a hydroxyl group-containing compound component with a specific pH range, it is possible to slightly reduce its acid resistance and metal plating resistance while maintaining drying control range, resolution, alkali resistance, and solvent resistance, but simultaneously improving sensitivity. Furthermore, surprisingly, by adding a hydroxyl group-containing compound component with a specific pH range in a specific content, acid resistance and metal plating resistance can be further improved.

[0056] From the viewpoint of achieving the above objectives of the present invention, the pH range of the hydroxyl group-containing compound component is 4.0 or more and 5.5 or less, preferably 4.0 or more and 5.2 or less, and more preferably 4.0 or more and 5.0 or less. The pH value is measured according to DIN 19268. Furthermore, the acid value of the hydroxyl group-containing compound is 10 to 100 mg KOH / g, preferably 20 to 80 mg KOH / g, and more preferably 25 to 60 mg KOH / g.

[0057] If the pH value of the hydroxyl group-containing compound component is within the above range, any substance can be used as the hydroxyl group-containing compound having at least one hydroxyl group in its molecule (hereinafter sometimes simply referred to as "hydroxyl group-containing compound"). For example, substances having one or more alcoholic hydroxyl groups and / or phenolic hydroxyl groups in their molecule can be used. More specifically, examples include alcohols (including monohydric alcohols and / or polyhydric alcohols), phenols (including monohydric phenols and / or polyhydric phenols), ethers (including esters formed from monohydric alcohols and / or polyhydric alcohols, monohydric phenols or esters formed from polyhydric phenols), esters (including esters formed from monohydric alcohols and / or polyhydric alcohols, monohydric phenols or esters formed from polyhydric phenols), polymers having hydroxyl groups in their side chains and / or terminals, etc. These hydroxyl group-containing compounds may be used alone or in combination of two or more types. The hydroxyl group-containing compound is preferably a polymer having a hydroxyl group in its side chain and / or terminal, and more preferably a polymer having both a hydroxyl group and a carboxyl group in its side chain and / or terminal.

[0058] Within limits that do not affect the objectives of the present invention, the main chain and / or side chain of the hydroxyl group-containing compound may optionally contain other substituents. Examples include alkyl groups (preferably having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms), alkoxy groups (preferably having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms), alkenyl groups (preferably having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms), alkynyl groups (preferably having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms), amino groups, halogen atoms, amine groups (preferably with the N atom substituted with an alkyl group having 1 to 8 carbon atoms, and more preferably with an alkyl group having 1 to 4 carbon atoms), carboxyl groups, and the like.

[0059] The hydroxyl group-containing compound may contain other components, such as solvents, to the extent that it does not affect the purpose of the present invention.

[0060] The content of the hydroxyl group-containing compound component within the specified pH range is 1.2 to 7.8 parts by mass, more preferably 1.5 to 6 parts by mass, per 100 parts by mass of the carboxyl group-containing vinyl ester resin, on a solid content basis. If the content is too low, there is room for improvement in terms of acid resistance and metal plating resistance. If the content is too high, acid resistance and pencil hardness tend to deteriorate. By adding the hydroxyl group-containing compound component within the above content range within the specified pH range, the alkali-developable resin composition has excellent drying control range, sensitivity, and resolution, and the cured product has excellent pencil hardness, acid resistance, metal plating resistance, alkali resistance, and solvent resistance. Surprisingly, acid resistance and metal plating resistance are further improved compared to the use of melamine.

[0061] From the viewpoint of making it easier to achieve the objectives of the present invention, the molecular weight of the hydroxyl group-containing compound is preferably 500 to 5000 in number average molecular weight, more preferably 1000 to 4000, and even more preferably 1500 to 3000. In weight average molecular weight, it is preferably 1000 to 6000, more preferably 2000 to 5000, and even more preferably 3000 to 4000.

[0062] A commercially available product containing a hydroxyl group within the aforementioned specific pH range is TECH-7200 (Shanghai Tiger Polymer Technology Co., Ltd.).

[0063] solvent In the present invention, a solvent may be used in at least one component system for general purposes such as preparing each component system of an alkali-developable resin composition and adjusting its viscosity.

[0064] As the aforementioned solvent, general organic solvents can be used. Examples 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.

[0065] These solvents can be used individually or in combination of two or more types.

[0066] In terms of solid content, the solvent content in the main component composition of the alkali-developable resin composition of the present invention is preferably in the range of 25 to 110 parts by mass per 100 parts by mass of carboxyl group-containing vinyl ester resin.

[0067] Other ingredients In the alkali-developable resin composition of the present invention, it is of course possible to incorporate further additives as other components as necessary, without departing from the objectives of the present invention.

[0068] Examples of such components include colorants such as pigments and dyes, thermal polymerization inhibitors, ultraviolet absorbers, plasticizers, flame retardants, antistatic agents, anti-aging agents, antibacterial and antifungal agents, defoaming agents, leveling agents, anti-sagging agents, thickeners, adhesion promoters, thixotropic agents, photoinitiator aids, sensitizers, photobase generators, thermoplastic resins, elastomers, organic fillers, release agents, surface treatment agents, dispersants, dispersion aids, surface modifiers, stabilizers, phosphors, cellulose resins, and the like.

[0069] The main component 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.

[0070] Dry film A dry film can be produced from the alkali-developable resin composition of the present invention.

[0071] 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. When forming the dry film, first, in the case of a two-component system, the main component composition and the curing agent composition are thoroughly mixed to obtain the alkali-developable resin composition of the present invention. Then, either as is, or diluted with a high-boiling point solvent as needed to adjust to an appropriate viscosity, it is applied to the carrier film to a uniform thickness using a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, etc. After that, the applied composition can be dried at a temperature of 50 to 130°C for 1 to 30 minutes to form the resin layer. There are no particular restrictions on the coating film thickness, but generally, the film thickness after drying is appropriately selected in the range of 10 to 150 μm, preferably 20 to 60 μm.

[0072] As the carrier film, a plastic film is used, such as polyester film (e.g., polyethylene terephthalate (PET)), polyimide film, polyamide-imide film, polypropylene film, or polystyrene film. There are no particular restrictions on the thickness of the carrier film, but it is generally selected appropriately within the range of 10 to 150 μm.

[0073] 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 purposes such as preventing dust from adhering to the surface of the resin layer. Examples of peelable cover films that can be used include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper. The cover film only needs to have an adhesive strength that is weaker than the adhesive strength between the resin layer and the carrier film when the cover film is peeled off.

[0074] In addition, in the present invention, a resin layer may be formed by applying and drying the alkali-developable resin composition of the present invention on the cover film, and then laminating a carrier film on its surface. That is, in the present invention, when manufacturing 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.

[0075] Here, the alkali-developable resin composition of the present invention can be adjusted to a viscosity suitable for the coating method using a high-boiling point solvent, and then applied to a substrate by methods such as dip coating, flow coating, roll coating, bar coating, screen printing, or curtain coating. After application, the high-boiling point solvent contained in the composition is evaporated and dried (pre-dried) at a temperature of approximately 60 to 100°C to form a tack-free resin layer. Furthermore, in the case of a dry film in which the above composition is applied to a carrier film, dried, and wound as a film, the resin layer of the present invention can be bonded to the substrate using a laminator or the like so that it comes into contact with the substrate, and then the carrier film is peeled off to form a resin layer on the surface of the substrate.

[0076] The above-mentioned substrates include printed circuit boards and flexible printed circuit boards with circuits already formed using copper, as well as materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / nonwoven fabric epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, and copper-clad laminates for high-frequency circuits using fluororesin, polyethylene, polyphenylene ether, polyphenylene oxide, cyanate, etc. Examples include copper-clad laminates of all grades (FR-4, etc.), metal substrates, polyimide films, PET films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafers, etc.

[0077] cured product To form a cured product using the alkali-developable resin composition of the present invention, the composition is applied to a substrate, and after the solvent has evaporated and dried, the resulting resin layer is exposed (irradiated with light) to cure the exposed area (the part that has been irradiated with light). Specifically, the resin layer is selectively exposed with active energy rays through a photomask with a pattern formed on it using a contact or non-contact method, or the pattern is directly exposed using a laser direct exposure machine, and the unexposed areas are developed with an alkaline aqueous solution (for example, a 0.3-3% by mass sodium carbonate aqueous solution) to form a resist pattern. Furthermore, by heating to a temperature of approximately 100-180°C and performing thermal curing (post-curing), a cured film (cured product) with excellent properties such as heat resistance, chemical resistance, moisture resistance, adhesion, and electrical properties can be formed.

[0078] The volatilization drying or thermal curing when forming the above-mentioned 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 inside the dryer is brought into countercurrent contact using a heat source equipped with a steam-heated air heating method, or a method in which hot air is blown onto the support from a nozzle).

[0079] Furthermore, the exposure machine used for the above-mentioned active energy ray irradiation can be any device equipped with a high-pressure mercury lamp, ultra-high-pressure mercury lamp, metal halide lamp, mercury short-arc lamp, etc., that irradiates ultraviolet light in the range of 350 to 450 nm. In addition, a direct writing device (for example, a laser direct imaging device that directly draws images with a laser using CAD data from a computer) can also be used. The lamp light source or laser light source of the direct writing device can have a maximum wavelength in the range of 350 to 410 nm. The exposure amount for image formation varies depending on the film thickness, etc., but is generally 20 to 1000 mJ / cm². 2 Preferably 20-800 mJ / cm² 2 It can be within the range of

[0080] Next, in the development step, the resin layer after the exposure step is treated with a developing solution. In this way, the unexposed portions of the coating film are removed, and a patterned film of the alkali-developable resin composition of the present invention is formed.

[0081] Here, the dipping method, shower method, spray method, brush method, etc., can be used as the developing process. Typically, a sodium carbonate aqueous solution with a mass concentration of 0.5 to 5% can be used as the developer, but other alkaline aqueous solutions such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium silicate, ammonia, and amines can also be used.

[0082] In this developing process, the developer solution temperature is 20-40°C and the developing time is 180 seconds or less.

[0083] During this development process, the resulting pattern film may be washed with a rinsing solution as needed. Distilled water, methanol, ethanol, isopropyl alcohol, etc., can be used as the rinsing solution, either alone or in combination.

[0084] Electronic components Furthermore, the present invention can also provide electronic components having the above-mentioned cured product.

[0085] The alkali-developable resin composition or dry film of the present invention can be used as a protective film for printed circuit boards and semiconductor elements, an electrical insulating layer, a sealing material for sealing or embedding electronic components, a component embedding layer, an adhesive layer for fixing electronic components, etc. It is particularly suitable for high-density wiring requiring low dielectric constant and low dielectric loss tangent, electronic components for processing high-frequency signals, and electronic components for vehicles and robots requiring high temperature and long-term reliability.

[0086] In this invention, "electronic components" refers to components used in electronic circuits, and includes not only active components such as printed circuit boards, transistors, light-emitting diodes, and laser diodes, but also passive components such as resistors, capacitors, inductors, and connectors.

[0087] The following examples illustrate one aspect of the present invention, but of course, the purpose is not to limit the scope of the invention claimed in this application.

[0088] Furthermore, unless otherwise specified, the indicated "parts" and "%" are based on mass. Examples

[0089] [Synthesis example: Synthesis of carboxyl group-containing vinyl ester resin] In a high-pressure vessel equipped with a thermometer, a nitrogen introduction device / alkylene oxide introduction device, and a stirring device, 119.4 parts of cresol novolac resin (Shonol CRG-951, manufactured by Aica Kogyo Co., Ltd., OH equivalent: 119.4), 1.19 parts of potassium hydroxide, and 119.4 parts of toluene were introduced. The system was then heated and the temperature increased while stirring and nitrogen was purged into the atmosphere. Subsequently, 63.8 parts of propylene oxide were slowly added dropwise, and the temperature was raised to 125-132°C and 0-4.8 kg / cm³. 2 The reaction was carried out for 16 hours. After cooling to room temperature, 1.56 parts of 89% phosphoric acid were added to the reaction solution and mixed to neutralize the potassium hydroxide, yielding a propylene oxide reaction solution of novolac-type cresol resin with a non-volatile content of 62.1% and a hydroxyl value of 182.2 mg KOH / g (307.9 g / eq.). On average, 1.08 moles of propylene oxide were added per equivalent of phenolic hydroxyl groups.

[0090] 293.0 parts of the propylene oxide reaction solution of the obtained novolac-type cresol resin, 43.2 parts of acrylic acid, 11.53 parts of methanesulfonic acid, 0.18 parts of methylhydroquinone, and 252.9 parts of toluene were introduced into a reactor equipped with a stirrer, thermometer, and air blowing tube. Air was blown in at a rate of 10 ml / min, and the reaction was carried out at 110°C for 12 hours while stirring. 12.6 parts of the water produced by the reaction were removed by distillation as an azeotrope with toluene. The solution was then cooled to room temperature, neutralized with 35.35 parts of 15% sodium hydroxide aqueous solution, and washed with water. Subsequently, toluene was replaced with 118.1 parts of diethylene glycol monoethyl ether acetate using an evaporator, and the mixture was removed by distillation to obtain a novolac-type acrylate resin solution.

[0091] Next, 332.5 parts of the obtained novolac-type acrylate resin solution and 1.22 parts of triphenylphosphine were introduced into a reactor equipped with a stirrer, thermometer, and air blowing tube. Air was blown in at a rate of 10 ml / min, and 60.8 parts of tetrahydrophthalic anhydride were slowly added while stirring. The mixture was reacted at 95-101°C for 6 hours, then cooled and removed. In this way, a carboxyl group-containing vinyl ester resin with a solid content of 65% and an acid value of 87.7 mgKOH / g of the solid content was obtained.

[0092] [Examples 1-3 and Comparative Examples 1-8] After mixing each component shown in Table 1 in the respective proportions using a mixer, the mixture was kneaded using a three-roll mill to prepare the alkali-developable resin compositions (two-component systems consisting of a main component and a curing agent) of Examples 1-3 and Comparative Examples 1-8, respectively.

[0093] [Table 1]

[0094] Each component listed in Table 1 is explained as follows. *1: The same carboxyl group-containing vinyl ester resin obtained in the synthesis example, with a solid content of 65% and a solvent content of 35%. *2: Black color powder: MA100 (carbon black) Mitsubishi Chemical Corporation, JY-140P (carbon black) Hangzhou Junyi New Materials Co., Ltd. *3: Defoaming agent: KS-66, manufactured by Shin-Etsu Chemical Co., Ltd. *4: Leveling agent: BYK-1790, manufactured by BYK (Shanghai) Co., Ltd. *5: Photopolymerization initiator: ITX, #369E, manufactured by Tianjin Jiuri New Materials Co., Ltd. *6: Silica, A-8, manufactured by Sibelco. *7: Barium sulfate: B-30, manufactured by Sakai Chemical Industry Co., Ltd. *8: Solvent: DPM: Manufactured by Taiwan Liante Co., Ltd. *9: Epoxy resin: N-770-75EA, manufactured by DIC Corporation, novolac-type polyfunctional epoxy resin, solids content 75% *10: Photosensitive monomer: DPHA, dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd. *11:MELAMINE-JC, manufactured by Jiangsu Jinxiangzaisui Chemical Co., Ltd. *12: Hydroxyl group-containing compound component: TECH-7200, manufactured by Shanghai Tiger Polymer Technology Co., Ltd., pH: 4.0~5.0, hydroxyl polyester compound, acid value: 30 mg KOH / g, number average molecular weight: 2037, weight average molecular weight: 3115 *13: Hydroxyl group-containing compound component: BYK-102, pH: 2.8, manufactured by BIC Chemie Japan Co., Ltd. *14: Hydroxyl group-containing compound component: BYK-220SN, pH: 3.5, manufactured by BIC Chemie Japan Co., Ltd. *15: Hydroxyl group-containing compound component: BYK-174, pH: 6.0, manufactured by BIC Chemie Japan Co., Ltd.

[0095] The main component compositions, curing agent compositions, and alkali-developable resin compositions obtained by mixing them in the examples and comparative examples were subjected to the following tests.

[0096] <Drying control range (time after drying until exposure and development are possible)> The alkali-developable resin compositions shown in Table 1 were applied to the entire surface of a copper foil substrate with a pattern formed on it by screen printing, and dried in a hot air circulating drying oven at 80°C. After the start of drying, the substrate was removed every 10 minutes from 20 to 70 minutes and slowly cooled to room temperature. The substrate was developed using a 1 wt% sodium carbonate aqueous solution at 30°C at a spray pressure of 0.2 MPa for 60 seconds, and the maximum allowable drying time at which no residue remained was defined as the drying control range. ○: Maximum allowable drying time without residue is 50 minutes or more. ×: Maximum allowable drying time without residue is less than 50 minutes.

[0097] <Sensitivity> After polishing the copper-free substrates using a jet scrubber, they were rinsed with water and dried. Then, the alkali-developable resin compositions shown in Table 1 were applied by screen printing, and dried in a hot air circulating drying oven at 80°C for 30 minutes. After drying, exposure at 300 mJ / cm² was applied using a step tablet (Kodak No. 2). 2 The number of step tablets remaining after exposure and development with a 1 wt% sodium carbonate aqueous solution at 30°C at a spray pressure of 0.2 MPa for 60 seconds was evaluated as sensitivity.

[0098] <Resolution> The alkali-developable resin compositions shown in Table 1 are applied to a copper-free substrate (FR4) by screen printing or spraying to a dry film thickness of 42 ± 2 μm. After drying (80°C, 30 minutes), a predetermined photomask is placed in close contact with the coating and exposed to light (exposure on the masking material is 300 mJ / cm²). 2 The sample was then developed (1 wt% Na2CO3, 30°C, 0.2 MPa, 60 seconds) to prepare a test specimen. The thinnest line remaining on this specimen was visually inspected.

[0099] <Pencil hardness> The manufacturing process for the circuit board is as follows: The alkali-developable resin compositions of the examples and comparative examples were screen-printed onto copper-clad laminates to a thickness of 20 μm, and dried in a hot air circulating drying oven at 80°C for 30 minutes. After cooling to room temperature, exposure was performed using an exposure apparatus equipped with a high-pressure mercury lamp at 300 mJ / cm². 2 A complete exposure was performed. Next, the substrate was developed with a 1 wt% sodium carbonate aqueous 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 to produce evaluation substrate A with a cured film. The pencil hardness of the resin surface of substrate A was measured and evaluated in accordance with JIS K 5600-5-4. The evaluation criteria are as follows: ◎: Pencil hardness of 6H or higher ○: Pencil hardness between 4H and 6H △: Pencil hardness less than 4H

[0100] <Acid resistance> The manufacturing process of the substrate is as follows. The alkali-developable resin compositions of the examples and comparative examples were each applied entirely to a copper-clad laminate by screen printing so as to have a thickness of 20 μm, and dried in a hot air circulation drying oven at 80°C for 30 minutes. After cooling to room temperature, image transfer was performed using an exposure apparatus equipped with a high-pressure mercury lamp at 300 mJ / cm 2 (a window pattern such as a circle appeared). Next, after developing with 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 in a hot air circulation drying oven at 150°C for 60 minutes to produce an evaluation substrate B having a cured film. The evaluation substrate B was immersed in a 10 vol% H2SO4 aqueous solution at room temperature for 20 minutes, and this was repeated 5 times in total. Penetration and elution of the coating film were visually confirmed, and peeling due to tape peeling was further confirmed. ○: No change was observed △: Only slightly changed ×: The coating film swelled, swelled and peeled off

[0101] <Metal plating resistance> The manufacturing process of the substrate is as follows. The alkali-developable resin compositions of the examples and comparative examples were each applied entirely to a copper-clad laminate by screen printing so as to have a thickness of 20 μm, and dried in a hot air circulation drying oven at 80°C for 30 minutes. After cooling to room temperature, image transfer was performed using an exposure apparatus equipped with a high-pressure mercury lamp at 300 mJ / cm 2 (a window pattern such as a circle appeared). Next, after developing with 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 in a hot air circulation drying oven at 150°C for 60 minutes to produce an evaluation substrate B having a cured film. Using a commercially available electroless nickel plating bath and electroless gold plating bath, plating was performed under the conditions of 0.5 μm of nickel and 0.03 μm of gold, the presence or absence of plating penetration was evaluated, and then the presence or absence of peeling of the cured film of the evaluation substrate B was evaluated by tape peeling. The criteria for judgment are as follows. ○: No penetration or peeling was observed △: Slight penetration is observed after plating, and peeling is observed after tape removal. ×: Peeling after plating

[0102] <Alkali resistance> The manufacturing process for the circuit board is as follows: The alkali-developable resin compositions of the examples and comparative examples were screen-printed onto copper-clad laminates to a thickness of 20 μm, and dried in a hot air circulating drying oven at 80°C for 30 minutes. After cooling to room temperature, exposure was performed using an exposure apparatus equipped with a high-pressure mercury lamp at 300 mJ / cm². 2 Image transfer was performed (circular and other window patterns appeared). Next, the substrate was developed with a 1 wt% sodium carbonate aqueous 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 to produce evaluation substrate B with a cured film. Evaluation substrate B was immersed in a 10 vol% NaOH aqueous solution at room temperature for 20 minutes. Penetration and dissolution of the coating film were visually confirmed, and peeling due to tape removal was also checked. ○: No change observed △: Only a slight change ×: The paint film swelled or swelled and peeled off.

[0103] <Solvent resistance> The manufacturing process for the circuit board is as follows: The alkali-developable resin compositions of the examples and comparative examples were screen-printed onto copper-clad laminates to a thickness of 20 μm, and dried in a hot air circulating drying oven at 80°C for 30 minutes. After cooling to room temperature, exposure was performed using an exposure apparatus equipped with a high-pressure mercury lamp at 300 mJ / cm². 2 Image transfer was performed (window patterns such as circles and squares appeared). Next, the substrate was developed with a 1 wt% sodium carbonate aqueous 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 to produce evaluation substrate B with a cured film. Evaluation substrate B was immersed in propylene glycol monomethyl ether at room temperature for 30 minutes. Penetration and dissolution of the coating film were visually confirmed, and peeling due to tape removal was also checked. ○: No change observed △: Only a slight change ×: The paint film swelled or swelled and peeled off.

[0104] The results shown in Table 1 indicate that the alkali-developable resin composition of the present invention has excellent drying control range, sensitivity, and resolution, and that the cured product formed therefrom has excellent pencil hardness, acid resistance, metal plating resistance, alkali resistance, and solvent resistance.

[0105] On the other hand, Comparative Examples 1 and 2, in which the curing agent component contains melamine but does not contain a hydroxyl group-containing compound component, show a decrease in sensitivity of 1 to 2 steps, and as the amount of melamine decreases, acid resistance and metal plating resistance tend to decrease. Comparative Example 3, in which the curing agent component does not contain either melamine or a hydroxyl group-containing compound component, exhibits poor acid resistance and metal plating resistance. Comparative Examples 4 to 6, in which the curing agent component does not contain melamine but contains a hydroxyl group-containing compound component with a pH value outside the specified range, exhibit poor acid resistance and metal plating resistance. Comparative Examples 7 and 8, in which the hydroxyl group-containing compound component has a pH value within the specified range but its content is insufficient or excessive, have room for improvement in terms of acid resistance and metal plating resistance (basically at the same level as Comparative Examples 1 and 2), and Comparative Example 8 tends to show a decrease in pencil hardness.

[0106] In contrast, the alkali-developable resin compositions of each example contain a hydroxyl group-containing compound component with a pH value within a specific range in the main component, resulting in a composition with excellent drying control range, sensitivity, and resolution. The cured product exhibits excellent pencil hardness, acid resistance, metal plating resistance, alkali resistance, and solvent resistance. Surprisingly, the acid resistance and metal plating resistance are even better than when melamine is used. Therefore, the melamine-free alkali-developable resin composition of the present invention is particularly suitable for cured products of printed circuit boards using photolithography, such as solder resists, and for electronic components having such cured products.

Claims

1. A melamine-free alkali-developable resin composition comprising at least two components of resin composition, It contains epoxy resin, carboxyl group-containing vinyl ester resin, photopolymerization initiator, photosensitive monomer, inorganic filler, and hydroxyl group-containing compound component. The carboxyl group-containing vinyl ester resin and the inorganic filler, and the epoxy resin and the photosensitive monomer are each contained in different resin compositions. The pH value of the hydroxyl group-containing compound component is 4.0 or higher and 5.5 or lower, and the hydroxyl group-containing compound component includes a hydroxyl group-containing compound having at least one hydroxyl group in its molecule. A melamine-free alkali-developable resin composition characterized in that the content of the hydroxyl group-containing compound component is 1.2 to 7.8 parts by mass per 100 parts by mass of the carboxyl group-containing vinyl ester resin, on a solid content basis.

2. The melamine-free alkali-developable resin composition according to claim 1, characterized in that the hydroxyl group-containing compound having at least one hydroxyl group in the molecule is at least one or more selected from the group consisting of alcohols, phenols, ethers, esters, and polymers.

3. The melamine-free alkali-developable resin composition according to claim 1 or 2, characterized in that the hydroxyl group-containing compound having at least one hydroxyl group in the molecule is a polymer having a hydroxyl group in its side chain and / or terminal.

4. The melamine-free alkali-developable resin composition according to claim 1 or 2, characterized in that the acid value of the hydroxyl group-containing compound component having at least one hydroxyl group in the molecule is 10 to 100 mg KOH / g.

5. The melamine-free alkali-developable resin composition according to claim 1 or 2, characterized in that the molecular weight of the hydroxyl group-containing compound having at least one hydroxyl group in the molecule is in the range of 500 to 5000 in number average molecular weight.

6. The melamine-free alkali-developable resin composition according to claim 1 or 2, characterized in that the carboxyl group-containing vinyl ester resin, the photopolymerization initiator, the inorganic filler, and the hydroxyl group-containing compound component, the epoxy resin, and the photosensitive monomer are each contained in different resin compositions.

7. A dry film having a resin layer obtained by coating and drying a melamine-free alkali-developable resin composition according to any one of claims 1 to 6 onto a carrier film.

8. A cured product characterized by being obtained by curing a melamine-free alkali-developable resin composition according to any one of claims 1 to 6.

9. A cured product characterized by being obtained by curing the resin layer of the dry film described in claim 7.

10. An electronic component characterized by having a cured product according to claim 8 or 9.

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