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

Abstract

An alkali-developable resin composition, a dry film, a cured product, and an electronic component having the cured product. The alkali-developable resin composition is composed of a resin composition having at least two component systems. The alkali-developable resin composition comprises: (A) an epoxy resin, (B) a carboxyl-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-containing vinyl ester resin, (C) photopolymerization initiator, (E) inorganic filler and (F) high-boiling point solvent are contained in a different resin composition from the (A) epoxy resin and (D) photosensitive monomer. The boiling point of the (F) high-boiling point solvent is greater than 250°C and less than 280°C.

Description

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

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

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

[0003] Solder resist (also known as solder mask ink) has long been used as a protective material for printed circuit boards (PCBs). Conventional solder resists use highly volatile, low-boiling-point solvents, which can cause defects such as bubbles and pinholes during application. Furthermore, their high volatility also increases environmental impact.

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

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

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: CN 108219585A

[0009] Patent Document 2: CN 113604103A

[0010] Summary of the Invention

[0011] Technical Problems to be Solved by the Invention

[0012] Conventional developing solder resists have traditionally used aromatic solvents (such as the heavy aromatic solvent naphtha S-150) and low-boiling-point esters or ethers (such as dipropylene glycol monomethyl ether and diethylene glycol ethyl ether acetate). These solvents typically contain volatile organic compounds (VOCs) exceeding 20%, posing a significant environmental hazard. Furthermore, due to their rapid evaporation, these solvents can easily generate bubbles when printing on thick copper plates (e.g., copper thicknesses of 2 oz (70 μm) or greater), or when printing thick films. This can lead to undesirable effects such as orange peel (bumps and wrinkles on the painted surface) and pinholes (removed bubble marks, resembling a needle-punctured surface).

[0013] Therefore, it is desirable to develop an alkaline-developable resin composition with low volatility (VOCs value below 10%) and excellent photosensitivity while maintaining ink performance. Furthermore, the resulting cured product (paint film) exhibits excellent hardness, further improving text adhesion, tightness, and thermal cycling crack resistance.

[0014] In addition, from the perspective of ink performance, it is expected to obtain an alkaline-developable resin composition that is less likely to cause bubbles when printing on thick copper plates, has excellent coating appearance, better leveling properties, reduces the occurrence of undesirable conditions such as orange peel and pinholes in the paint film, and has better adhesion.

[0015] The coating has excellent dryness to the touch, and there is no film indentation on the coating surface when exposed. On the contrary, if the dryness to the touch is poor, the coating surface is more sticky, and film indentation is easily generated on the coating surface during exposure. After the coating is cured, the surface of the cured coating is also more likely to have indentation marks, and the appearance deteriorates.

[0016] Therefore, an object of the present invention is to provide an alkali-developable resin composition having excellent coating film dryness to touch, excellent appearance, letter adhesion, adhesion and crack resistance of its cured product, low volatility and excellent ink performance.

[0017] A further object of the present invention is to provide a dry film and a cured product having excellent properties as described above, obtained by using such an alkaline-developable solder resist composition, and a printed wiring board having a cured film of a solder resist or the like formed thereon as the cured product.

[0018] Solutions for solving problems

[0019] The present inventors have conducted intensive research and have found that the above-mentioned problems can be solved by the following alkaline-developable resin composition. The alkaline-developable resin composition is composed of at least a two-component resin composition, characterized in that the alkaline-developable resin composition contains: (A) an epoxy resin, (B) a carboxyl group-containing vinyl ester resin, (C) a photopolymerization initiator, (D) a photosensitive monomer, (E) an inorganic filler, and (F) a high-boiling-point solvent.

[0020] 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 different resin compositions from the (A) epoxy resin and the (D) photosensitive monomer.

[0021] The present invention has been completed by finding that the boiling point of the high-boiling-point solvent (F) is higher than 250°C and lower than 280°C.

[0022] Among them, a preferred embodiment of the present invention relates to an alkaline-developable resin composition, characterized in that the (F) high-boiling-point solvent is at least one or two or more selected from the group consisting of polyol ethers, polyol esters, organic acid alkyl esters and aliphatic hydrocarbons.

[0023] Furthermore, a preferred embodiment of the present invention relates to an alkaline-developable resin composition, characterized in that the high-boiling-point solvent (F) is at least one or two 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.

[0024] Furthermore, a 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 per 100 parts by mass of the (B) carboxyl group-containing vinyl ester resin in terms of solid content.

[0025] Furthermore, a more 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.

[0026] Furthermore, a more preferred embodiment of the present invention relates to an alkaline-developable resin composition, wherein the content of the volatile organic compound is 10% or less by mass.

[0027] Moreover, 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 on a carrier film and drying the resultant.

[0028] Still another embodiment of the present invention relates to the alkali-developable resin composition, characterized in that the composition is used as a material for a solder resist.

[0029] Still another embodiment of the present invention relates to: a cured product obtained by curing an alkaline-developable resin composition; a cured product obtained by curing a resin layer of a dry film; and an electronic component comprising these cured products.

[0030] Effects of the Invention

[0031] According to the present invention, an alkaline-developable resin composition can be provided, which has excellent coating film drying properties to touch, and a cured product obtained by curing the alkaline-developable resin composition has excellent appearance, letter adhesion, adhesion, and crack resistance, and has low volatility and excellent photosensitivity and ink properties.

[0032] Furthermore, the present invention can provide a dry film and cured product having excellent properties as described above obtained by using such an alkaline-developable resin composition, and an electronic component such as a printed wiring board having a cured film such as a solder resist formed thereon as the cured product. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a photograph showing cracks in a solder resist film for evaluating thermal shock resistance in a comparative example (NG: cracks).

[0034] FIG. 2 is a photograph showing that the solder resist film used for evaluating thermal shock resistance in Examples was not cracked (OK: no cracking). DETAILED DESCRIPTION

[0035] The alkaline-developable resin composition of the present invention is preferably composed of at least a two-component resin composition. For example, a two-component system can be employed, wherein one resin composition serves as a base composition and the other resin composition serves as a curing agent composition. In this case, for example, it is preferred that the base composition 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 comprises at least (A) an epoxy resin and (D) a photosensitive monomer.

[0036] Here, from the viewpoint of preventing chemical reactions during storage, it is preferred that (A) the epoxy resin and (B) the carboxyl group-containing vinyl ester resin are directly contained in separate compositions, and (D) the photosensitive monomer and (C) the photopolymerization initiator are directly contained in separate compositions.

[0037] Furthermore, if (B) the carboxyl vinyl ester resin and (C) the photopolymerization initiator are combined in the same composition, the detailed mechanism is unclear, but the composition may suffer from poor appearance and coarse particles. However, the present inventors have discovered that using a main agent comprising at least (B) the carboxyl vinyl ester resin, (C) the photopolymerization initiator, and (F) a high-boiling-point solvent within a specific boiling point range can reduce VOC content while also improving this problem.

[0038] Hereinafter, each component constituting the alkali-developable resin composition of the present invention will be described.

[0039] (A) Epoxy resin

[0040] (A) The epoxy resin functions as a thermosetting component in the alkaline-developable resin composition to form a cured product.

[0041] As such an epoxy resin (A), a well-known and commonly used multifunctional epoxy resin having at least two epoxy groups in one molecule can be used.

[0042] (A) The epoxy resin may be in a liquid state, a solid state, or even a semi-solid state.

[0043] As the multifunctional epoxy resin, preferably bisphenol A type epoxy resin; brominated epoxy resin; novolac type epoxy resin; bisphenol F type epoxy resin; hydrogenated bisphenol A type epoxy resin; glycidylamine type epoxy resin; hydantoin type epoxy resin; alicyclic epoxy resin; trishydroxyphenylmethane type epoxy resin; bixylenol type or biphenol type epoxy resin or a mixture thereof; bisphenol S type epoxy resin; bisphenol A novolac type epoxy resin; tetrahydroxyphenylethane type epoxy resin; Resin; heterocyclic epoxy resin; diglycidyl phthalate resin; tetraglycidyl ditoluoyl ethane resin; naphthyl-containing epoxy resin; epoxy resin having a dicyclopentadiene skeleton; glycidyl methacrylate copolymer epoxy resin; copolymerized epoxy resin of cyclohexylmaleimide and glycidyl methacrylate; epoxy-modified polybutadiene rubber derivative; CTBN-modified epoxy resin, epoxy resin having an isocyanurate ring, etc., but of course not limited to these.

[0044] These epoxy resins can be used alone or in combination of two or more.

[0045] The "solid or semi-solid epoxy resin at room temperature" in the component (A) can also be a well-known commonly used one. For example, examples of epoxy resins that are solid at room temperature include bisphenol A epoxy resin (jER1001 manufactured by Mitsubishi Chemical Corporation, 128E manufactured by Nan Ya Plastics Co., Ltd.), bisphenol F epoxy resin (jER4004P manufactured by Mitsubishi Chemical Corporation), naphthalene epoxy resin (HP-4700 manufactured by DIC Corporation), multifunctional solid epoxy resin containing a naphthalene skeleton (NC-7000 manufactured by Nippon Kayaku Co., Ltd.), trisphenol epoxy resin (EPPN-502H manufactured by Nippon Kayaku Co., Ltd.), multifunctional solid epoxy resin containing a dicyclopentadiene skeleton (Epiclon manufactured by DIC Corporation), and epoxy resins having a tert-butyl ether. HP-7200), phosphorus-containing epoxy resin (TX0712 manufactured by Nippon Steel & Sumikin Chemicals Corporation), tris(2,3-epoxypropyl)isocyanurate (TEPIC manufactured by Nissan Chemical Industries, Ltd.); as epoxy resins that are semi-solid at room temperature, bisphenol A type epoxy resin (jER834 manufactured by Mitsubishi Chemical Corporation), naphthalene type epoxy resin (HP-4032 manufactured by DIC Corporation), etc. can be cited.

[0046] Here, in the present invention, being solid or semi-solid at room temperature means being solid or semi-solid at 15° C. Determination of solid or semi-solid can be made in accordance with Annex 2, "Method for Confirming Liquid State," of the Ministerial Ordinance concerning the Test and Properties of Dangerous Substances (Ministry of Home Affairs Ordinance No. 1 of 1991).

[0047] As the biphenyl-type epoxy resin in component (A), a well-known and commonly used multifunctional epoxy resin having a biphenyl skeleton can be used. Examples thereof include multifunctional solid epoxy resins containing a biphenyl skeleton (NC-3000H and NC-3000 manufactured by Nippon Kayaku Co., Ltd.) and biphenyl-type epoxy resins (YX-4000 and YL-6121HA manufactured by Mitsubishi Chemical Corporation).

[0048] Examples of the novolac-type epoxy resin in component (A) include cresol novolac-type epoxy resin (Epiclon N-690 manufactured by DIC Corporation), phenol novolac-type epoxy resin (Epiclon N-770 manufactured by DIC Corporation, jER152 manufactured by Mitsubishi Chemical Corporation), and bisphenol A novolac-type epoxy resin (BNE200D75 manufactured by Shanghai Hongze Chemical).

[0049] As the epoxy resin having an isocyanurate ring in the component (A), triglycidyl isocyanurate epoxy resin (TGIC-G manufactured by Shanghai Xindi Chemical Co., Ltd.) and the like can be mentioned.

[0050] The content of the epoxy resin (A) described above is preferably approximately 30 to 90 parts by mass, more preferably 40 to 80 parts by mass, relative to 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) in terms of solid content.

[0051] (B) Carboxyl vinyl ester resin

[0052] The carboxyl group-containing vinyl ester resin (B) used in the present invention is preferably one having an ethylenically unsaturated double bond in the molecule from the perspectives of alkali developability, photocurability, and development resistance. Furthermore, it is more preferred that the unsaturated double bond be derived from acrylic acid, methacrylic acid, or a derivative thereof. Specific examples of the carboxyl group-containing vinyl ester resin (B) are shown below.

[0053] (1) Carboxyl group-containing vinyl ester resins obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with one or more other compounds having unsaturated double bonds;

[0054] (2) Carboxyl group-containing vinyl ester resins obtained by adding an ethylenically unsaturated group as a pendant group to a copolymer of an unsaturated carboxylic acid such as (meth)acrylic acid and one or more other compounds having an unsaturated double bond, using a compound having an epoxy group and an unsaturated double bond, such as glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, or (meth)acryloyl chloride;

[0055] (3) Carboxyl group-containing vinyl ester resins obtained by reacting a copolymer of a compound having an epoxy group and an unsaturated double bond, such as glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate, and another compound having an unsaturated double bond, with an unsaturated carboxylic acid, such as (meth)acrylic acid, and reacting a polybasic acid anhydride with the resulting secondary hydroxyl group;

[0056] (4) Carboxyl group-containing vinyl ester resins obtained by reacting a copolymer of an acid anhydride having an unsaturated double bond, such as maleic anhydride, and another compound having an unsaturated double bond, with a compound having a hydroxyl group and an unsaturated double bond, such as 2-hydroxyethyl (meth)acrylate;

[0057] (5) Carboxyl group-containing vinyl ester resins obtained by reacting a polyfunctional epoxy compound with an unsaturated monocarboxylic acid and reacting a saturated or unsaturated polybasic acid anhydride with the resulting hydroxyl group;

[0058] (6) A vinyl ester resin containing hydroxyl groups and carboxyl groups obtained by reacting a hydroxyl-containing polymer such as a polyvinyl alcohol derivative with a saturated or unsaturated polybasic acid anhydride, and then reacting a compound having an epoxy group and an unsaturated double bond in one molecule with the resulting carboxylic acid;

[0059] (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;

[0060] (8) a carboxyl group-containing vinyl ester resin obtained by reacting an unsaturated monocarboxylic acid with a polyfunctional oxetane compound having at least two oxetane rings in one molecule, and reacting a saturated or unsaturated polybasic acid anhydride with the primary hydroxyl group in the resulting modified oxetane resin; and

[0061] (9) Carboxyl group-containing vinyl ester resins obtained by reacting a bifunctional epoxy compound with an unsaturated monocarboxylic acid and reacting a saturated or unsaturated polybasic acid anhydride with the generated hydroxyl group.

[0062] (10) Carboxyl group-containing vinyl ester resins obtained by reacting a polyfunctional epoxy resin such as a phenol novolac epoxy resin, a cresol novolac epoxy resin, a bisphenol A cresol novolac epoxy resin, or a dicyclopentadiene cresol novolac epoxy resin with (meth)acrylic acid, and adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the hydroxyl groups present in the side chains;

[0063] (11) reacting the multifunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of the multifunctional epoxy resin in the above-mentioned (10) with epichlorohydrin with (meth)acrylic acid, and adding a polybasic acid anhydride to the generated hydroxyl groups to obtain a carboxyl group-containing vinyl ester resin;

[0064] (12) Carboxyl group-containing vinyl ester resins obtained by adding cyclic ethers such as ethylene oxide or cyclic carbonates such as propylene carbonate to polyfunctional phenolic compounds such as novolac resins, partially esterifying the resulting hydroxyl groups with (meth)acrylic acid, and reacting the remaining hydroxyl groups with a polyacid anhydride;

[0065] (13) Carboxyl vinyl ester resins obtained by further adding a compound having one epoxy group and one or more (meth)acryloyl groups in the molecule, such as glycidyl (meth)acrylate or monomethylglycidyl (meth)acrylate, to any of the resins described above (10) to (12);

[0066] Particularly preferred among these examples are cresol novolac type and phenol novolac type, and the carboxyl group-containing vinyl ester resins (5), (10), (11), (12), and (13) mentioned above.

[0067] It should be noted that, in this specification, (meth)acrylate is a term that collectively refers to acrylate, methacrylate, and a mixture thereof, and the same applies to other similar expressions.

[0068] Since the carboxyl group-containing vinyl ester resin (B) described above has a plurality of free carboxyl groups on the side chains of the main chain polymer, it can be developed with a dilute alkaline aqueous solution.

[0069] The acid value of the carboxyl group-containing vinyl ester resin (B) is preferably in the range of 40 to 200 mgKOH / g, more preferably in the range of 45 to 120 mgKOH / g. If the acid value of the carboxyl group-containing resin is less than 40 mgKOH / g, alkali development becomes difficult. On the other hand, if it exceeds 200 mgKOH / g, dissolution of the exposed portion by the developer is promoted, resulting in thinner lines than desired. In some cases, the exposed and unexposed portions may be dissolved and peeled off indiscriminately by the developer, making it difficult to form a normal resist pattern. This is not preferred.

[0070] The weight-average molecular weight of the carboxyl group-containing vinyl ester resin (B) varies depending on the resin backbone, but is generally preferably in the range of 2,000 to 150,000, more preferably 5,000 to 100,000. A weight-average molecular weight of less than 2,000 may result in poor application to a substrate and poor tackiness (dry to touch) after drying. Furthermore, the moisture resistance of the coating film after exposure may deteriorate, film loss may occur during development, and resolution may be significantly reduced. On the other hand, a weight-average molecular weight exceeding 150,000 may result in significantly poor developability and poor storage stability.

[0071] (C) Photopolymerization initiator

[0072] Examples of the photopolymerization initiator (C) include bisacylphosphine oxides such as bis(2,6-dichlorobenzoyl)phenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; and bis(2,6-dimethoxybenzoyl)phenylphosphine oxide. Monoacylphosphine oxides such as phenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine oxide, methyl 2,4,6-trimethylbenzoyldiphenylphosphine oxide, isopropyl pivaloylphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide; hydroxyacetophenones such as 1-hydroxy-cyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propane-1-one, and 2-hydroxy-2-methyl-1-phenylpropane-1-one; benzoin, benzyl, and benzoin methyl Benzoins such as benzoin 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-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- Acetophenones such as 1-[4-(4-morpholinyl)phenyl]-1-butanone, N,N-dimethylaminoacetophenone, etc.; thioxanthones such as 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone, etc.; anthraquinones such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone, etc.; ketals such as acetophenone dimethyl ketal, benzil dimethyl ketal, etc.; benzoic acid esters such as ethyl 4-dimethylamino benzoate, 2-(dimethylamino)ethyl benzoate, and ethyl p-dimethylbenzoate;Oxime esters such as 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime) and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone 1-(O-acetooxime); titanocenes such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium and bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyrrol-1-yl)ethyl)phenyl]titanium; 2-nitrofluorene phenyl disulfide, butyroin, anisoin ethyl ether, azobisisobutyronitrile, and tetramethylthiuram disulfide. Photopolymerization initiators may be used alone or in combination of two or more.

[0073] The content of the photopolymerization initiator (C) is preferably 5 to 25 parts by mass relative to 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) in terms of solid content. When the content is 5 parts by mass or more, surface curability is improved, while when the content is 25 parts by mass or less, halation is less likely to occur, resulting in good resolution.

[0074] (D) Photosensitive monomer

[0075] The photosensitive monomer (D) is preferably a compound having one or more ethylenically unsaturated groups in its molecule. Such a photosensitive monomer (D) containing an ethylenically unsaturated group contributes to the photocuring of the carboxyl group-containing vinyl ester resin (B) by irradiation with active energy rays, thereby curing the alkaline-developable resin composition.

[0076] (D) The photosensitive monomer preferably used in the present invention includes, for example, methyl α-(allyloxymethyl)acrylate, or diol diacrylates such as 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, and 1,10-decanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, Tripropylene glycol diacrylate, polypropylene glycol diacrylate, neopentyl glycol diacrylate, diol diacrylates obtained by adding at least one of ethylene oxide and propylene oxide to neopentyl glycol, diol diacrylates such as caprolactone-modified hydroxypivalate neopentyl glycol diacrylate, bisphenol A EO adduct diacrylate, bisphenol A PO adduct diacrylate, tricyclodecane dimethanol diacrylate, hydrogenated dicyclopentadienyl diacrylate, cyclohexyl diacrylate esters, or bifunctional (meth)acrylates such as methacrylate monomers corresponding thereto, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolmethane triacrylate, ethylene oxide-modified trimethylolpropane triacrylate, propylene oxide-modified trimethylolpropane triacrylate, epichlorohydrin-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, tetramethylolmethane tetraacrylate, ethylene oxide-modified phosphoric acid triacrylate, epichlorohydrin-modified glycerol triacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, or polyfunctional acrylates such as silsesquioxane-modified products thereof, or methacrylate monomers corresponding thereto, trifunctional methacrylates, polyfunctional (meth)acrylates such as ε-caprolactone-modified tris(acryloyloxyethyl)isocyanurate, or combinations of two or more thereof.

[0077] The content of the photosensitive monomer (D) is preferably in the range of 2 to 20 parts by mass, more preferably in the range of 4 to 15 parts by mass, based on 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) in terms of solid content.

[0078] When the content of the photosensitive monomer (D) is within such a range, the alkali-developable resin composition has sufficient photocurability, patterning during development becomes more favorable, and dryness to touch also becomes favorable.

[0079] (E) Inorganic fillers

[0080] In the present invention, the (E) inorganic filler may be used alone or in combination of two or more.

[0081] The amount of the inorganic filler (E) is preferably 35 to 200 parts by mass, more preferably 50 to 150 parts by mass, relative to 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) in terms of solid content. When the amount of the inorganic filler (E) is 35 parts by mass or greater, a cured film having superior solder heat resistance, insulation reliability, and heat discoloration resistance tends to be obtained. When the amount of the inorganic filler (E) is 200 parts by mass or less, an alkaline-developable resin composition having superior degassing properties, resolution, and deep-section curing properties tends to be obtained.

[0082] Examples of the inorganic filler (E) include titanium oxide, silicon dioxide, barium sulfate, barium titanate, Neuburg silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, and aluminum nitride. Among these, at least one of talc, silicon dioxide, and barium sulfate is preferred from the perspectives of improving mechanical properties, heat resistance, and processability. The main agent preferably contains an inorganic filler, and barium sulfate is preferably used as the inorganic filler, as this can suppress cure shrinkage of the cured product of the alkaline-developable resin composition and improve properties such as adhesion and hardness.

[0083] (E) The inorganic filler may be surface-treated and used. More preferably, the surface of the inorganic filler is surface-treated to introduce curable reactive groups.

[0084] Here, the curable reactive group refers to a group that undergoes a curing reaction with (A) an epoxy resin or the like, or (B) a carboxyl group-containing vinyl ester resin, and may be a photocurable reactive group or a thermosetting reactive group. Examples of the photocurable reactive group include methacryloyl, acryloyl, vinyl, and styryl groups, while examples of the thermosetting reactive group include epoxy, amino, hydroxyl, carboxyl, isocyanate, imino, oxetanyl, mercapto, methoxymethyl, methoxyethyl, ethoxymethyl, ethoxyethyl, and oxazoline groups.

[0085] The method for introducing curable reactive groups into the surface of (E) the inorganic filler is not particularly limited, and can be introduced using a known conventional method. The surface of the inorganic filler can be treated with a surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group as an organic group. As coupling agents, silane coupling agents, titanium coupling agents, zirconium coupling agents, aluminum coupling agents, etc. can be used. It should be noted that, as inorganic fillers without a surface treatment of curable reactive groups, for example, silica-alumina surface treatment, titanate coupling agent treatment, aluminate coupling agent treatment, organically treated inorganic fillers, etc. can be cited.

[0086] The average particle size (D50) of the (E) inorganic filler is 2000 nm or less, more preferably 1200 nm or less. The lower limit thereof is preferably 0.1 nm or more in terms of the average particle size (D50).

[0087] (E) The smaller the average particle size of the inorganic filler, the more diffuse reflection during light irradiation is suppressed, and the micro-processing of the cured product pattern can be facilitated. The average particle size (D50) can be obtained using a laser diffraction particle size distribution measuring device and a measuring device based on a dynamic light scattering method. As a measuring device based on a laser diffraction method, MicrotracMT3300EXII manufactured by MicrotracBEL Inc. can be cited, and as a measuring device based on a dynamic light scattering method, Nanotrac Wave II UT151 manufactured by MicrotracBEL Inc. can be cited.

[0088] (F) High boiling point solvent

[0089] The alkaline-developable resin composition of the present invention achieves the above-mentioned object of the present invention by using a high-boiling-point solvent having a higher boiling point than conventional solvents in the main component.

[0090] Specifically, the inventors have discovered through extensive research that using a low-VOC (carboxylic vinyl ester) resin (B) in an alkaline-developable resin composition to reduce the VOC content to below 20% can increase the viscosity of the composition, leading to bubbles and poor print appearance. Furthermore, if the solvent's boiling point is too high (above 280°C), it becomes difficult to volatilize, resulting in a large amount of residual pre-bake residue and poor touch drying of the resin layer.

[0091] By using a high-boiling-point solvent within a specific boiling point range, exceeding 250°C and below 280°C, the alkaline-developable resin composition reduces bubbles during printing and improves cosmetic defects such as orange peel and pinholes in the coating film. While maintaining the ink properties of the alkaline-developable resin composition, its low volatility significantly reduces environmental impact. Furthermore, unexpectedly, it further improves adhesion and thermal cycling crack resistance. Excellent thermal cycling crack resistance indicates that the structure of the cured product is essentially uniform across all parts, less susceptible to stress differences caused by thermal expansion and cooling contraction, and indicates excellent mechanical properties such as hardness.

[0092] Such a high boiling point solvent may be, for example, any one or more selected from polyol ethers, polyol esters, organic acid alkyl esters (esters obtained by reacting an organic acid with a monohydric alcohol), aliphatic hydrocarbons, etc. Among them, polyol ethers and polyol esters are preferred, and polyol ethers are more preferred, from the perspective of further facilitating the achievement of the object of the present invention. These high boiling point solvents may be used alone or in combination of two or more.

[0093] 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.).

[0094] The content of the high boiling point solvent is 40 to 80 parts by mass, more preferably 45 to 75 parts by mass, further preferably 50 to 70 parts by mass, and most preferably 60 to 70 parts by mass, relative to 100 parts by mass of the carboxyl vinyl ester resin (B) in terms of solid content. If the content is too low, the ink performance is poor, and the adhesion of the cured film is low, and the resistance to cracking during hot and cold cycles is also poor. If the content is too high, there may be a tendency for dryness to deteriorate. By using a high boiling point solvent within the above content range, the alkaline developing resin composition has excellent ink performance while reducing the VOCs content. Bubbles are less likely to occur when printing thick copper plates, and the composition has better leveling properties. The cured product has an excellent appearance, and further improves adhesion and cracking resistance.

[0095] Other solvents

[0096] In the present invention, for general purposes, such as preparing the various component systems of the alkali-developable resin composition and adjusting the viscosity thereof, a solvent other than the above-mentioned high-boiling-point solvent may be used in at least one component system.

[0097] Solvents other than the high-boiling point solvents may be conventional organic solvents, examples of which include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monoether (DPM), dipropylene glycol diethyl ether, and tripropylene glycol monomethyl ether; esters such as ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate (CA), butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; and petroleum solvents such as petroleum ether, petroleum naphtha, solvent naphtha, and heavy aromatic solvent naphtha.

[0098] These conventional organic solvents can be used alone or in combination of two or more.

[0099] The content of the conventional solvent in the main agent composition of the alkaline-developable resin composition of the present invention is preferably in the range of 1 to 40 parts by mass, more preferably in the range of 10 to 25 parts by mass, per 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) on a solid basis. The content of the conventional solvent in the curing agent composition of the alkaline-developable resin composition of the present invention is preferably in the range of 2 to 35 parts by mass, more preferably in the range of 4 to 25 parts by mass, per 100 parts by mass of the carboxyl group-containing vinyl ester resin (B) on a solid basis.

[0100] Other ingredients

[0101] The alkali-developable resin composition of the present invention may, of course, contain further additives as other components as needed within the scope of the object of the present invention.

[0102] Examples of such components include colorants such as pigments and dyes, thermal polymerization inhibitors, thermal curing catalysts, ultraviolet absorbers, plasticizers, flame retardants, antistatic agents, antioxidants, volatile agents, antioxidants, antibacterial / antifungal agents, defoaming agents, leveling agents, anti-sag agents, thickeners, adhesion-imparting agents, thixotropy-imparting agents, photoinitiator aids, sensitizers, photobase generators, thermoplastic resins, elastomers, organic fillers, release agents, surface treatment agents, dispersants, dispersing aids, surface modifiers, stabilizers, phosphors, and cellulose resins.

[0103] Among these, melamine is preferably added. As an antioxidant, it improves the adhesion between the substrate and the cured film of the alkaline-developable resin composition by inhibiting oxidation of the conductor (copper) on the substrate. It also acts as a thermal curing catalyst, promoting the reaction between epoxy and carboxyl groups. This improves the acid and alkali resistance, metal plating resistance, adhesion, and hardness of the dry film and curing agent formed from the alkaline-developable resin composition.

[0104] Melamine may be optionally added to at least one of the base composition and curing agent composition of the alkaline-developable resin composition of the present invention. Adding melamine to the curing agent composition is more preferred to further facilitate the aforementioned effects. The amount of melamine added is preferably 0.1 to 20 parts by mass, and more preferably 0.5 to 15 parts by mass, per 100 parts by mass of the carboxyl group-containing vinyl ester resin (B), calculated as a solid content.

[0105] The base composition and curing agent composition of the alkali-developable resin composition of the present invention can be prepared by mixing and dispersing these components in predetermined amounts, for example, using a three-roll mill.

[0106] dry film

[0107] A dry film can be produced from the alkaline-developable resin composition of the present invention. The dry film of the present invention has a resin layer, which is obtained by coating the alkaline-developable resin composition of the present invention on a carrier film and drying it. When forming the dry film, first, in the case of a two-component system, the main agent composition and the curing agent composition are thoroughly mixed with each other to obtain the alkaline-developable resin composition of the present invention. After adjusting the viscosity to an appropriate level, the composition is diluted directly or as needed with a high-boiling point solvent, and then applied to a carrier film to a uniform thickness using a comma coater, a knife coater, a lip coater, a rod coater, an extrusion coater, a reverse coater, a transfer roll coater, a gravure coater, a spray coater, or the like. Thereafter, the applied composition is dried at a temperature of generally 50 to 130°C for 1 to 30 minutes to form a resin layer. There are no particular restrictions on the coating film thickness, but it is generally selected within the range of 10 to 150 μm, preferably 20 to 60 μm, based on the film thickness after drying.

[0108] As the carrier film, a plastic film is generally used, for example, polyester films such as polyethylene terephthalate (PET), polyimide films, polyamide-imide films, polypropylene films, polystyrene films, etc. The thickness of the carrier film is not particularly limited, but is generally selected within the range of 10 to 150 μm.

[0109] After forming a resin layer formed from the alkaline-developable resin composition of the present invention on a carrier film, it is preferable to further laminate a removable cover film on the surface of the resin layer to prevent dust and the like from adhering to the surface of the resin layer. Examples of the removable cover film include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper. The cover film may be any film as long as it is smaller than the adhesion between the resin layer and the carrier film when the cover film is peeled off.

[0110] It should be noted that in the present invention, the alkaline-developable resin composition of the present invention may be applied to the aforementioned cover film and dried to form a resin layer, and a carrier film may be laminated on the surface of the resin layer. In other words, in the present invention, when producing a dry film, either a carrier film or a cover film may be used as the thin film to which the curable composition of the present invention is applied.

[0111] Here, a tack-free resin layer can also be formed by adjusting the alkaline-developable resin composition of the present invention to a viscosity suitable for the coating method using, for example, a high-boiling-point solvent, and applying it to a substrate by dip coating, flow coating, roll coating, bar coating, screen printing, curtain coating, or the like, followed by volatilization and drying of the high-boiling-point solvent contained in the composition at a temperature of approximately 60 to 100° C. (temporary drying). Alternatively, when the composition is applied to a carrier film, dried, and wound as a thin film, the resin layer can be formed on the surface of the substrate by laminating the composition to the substrate using a laminator or the like so that the resin layer contacts the substrate, and then the carrier film is peeled off.

[0112] As the above-mentioned substrate, in addition to printed circuit boards and flexible printed circuit boards with circuits pre-formed from copper or the like, there can also be mentioned: copper-clad laminates of all grades (FR-4, etc.), as well as metal substrates, polyimide films, PET films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer plates, etc. The copper-clad laminates use materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven fabric epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, and copper-clad laminates for high-frequency circuits using fluorine·polyethylene·polyphenylene ether (polyphenylene oxide)·cyanate ester, etc.

[0113] Cured material

[0114] When forming a cured product using the alkaline developing resin composition of the present invention, the composition is applied to a substrate, the solvent is evaporated and dried, and a resin layer is obtained. The obtained resin layer is exposed (light irradiated) so that the exposed portion (the portion irradiated with light) is cured. Specifically, by contact or non-contact method, active energy rays are selectively exposed through a photomask having a pattern, or a laser direct exposure machine is used to directly expose the pattern, and an alkaline aqueous solution (for example, a 0.3-3% by mass sodium carbonate aqueous solution) is used to develop the unexposed portion to form a resist pattern. The alkaline developing resin composition of the present invention can form a pattern of a cured film after exposure and development, and therefore has excellent photosensitivity. Further heating to a temperature of about 100-180°C and performing thermal curing (post-curing) can form a cured film (cured product) having excellent properties such as heat resistance, chemical resistance, moisture absorption resistance, adhesion, and electrical properties.

[0115] The volatilization drying or thermal curing when forming the above-mentioned cured product can be carried out, for example, using a hot air circulation drying furnace, IR furnace, hot plate, convection oven, etc. (using a device with a heat source that uses steam to heat the air, a method of making the hot air in the dryer contact by convection, and a method of blowing it onto the support body using a nozzle).

[0116] In addition, as an exposure machine used in the above-mentioned active energy ray irradiation, any device that is equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, etc. and irradiates ultraviolet rays in the range of 350 to 450 nm can be used. Furthermore, a direct drawing device (for example, a laser direct imaging device that directly draws an image with a laser using CAD data from a computer) can also be used. As a lamp light source or a laser light source of a direct drawing machine, the maximum wavelength can be in the range of 350 to 410 nm. The exposure amount used for image formation varies depending on the film thickness, etc., and can usually be set to 20 to 1000 mJ / cm 2 , preferably can be set to 20 to 800 mJ / cm 2 within the range.

[0117] Next, in a development step, the resin layer after the exposure step is treated with a developer to remove the unexposed portion of the coating film, thereby forming a pattern film of the alkali-developable resin composition of the present invention.

[0118] Here, as the method used in the development step, an immersion method, a shower method, a spray method, a brush method, etc. can be used. As the developer, a sodium carbonate aqueous solution with a mass concentration of 0.5 to 5% can generally be used. Other alkaline aqueous solutions can also be used, such as alkaline aqueous solutions of potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, etc.

[0119] In this development step, the temperature of the developer is 20 to 40° C. and the development time is within 180 seconds.

[0120] In the development step, the obtained pattern film may be washed with a rinse solution as needed. As the rinse solution, distilled water, methanol, ethanol, isopropyl alcohol, etc. may be used alone or in combination.

[0121] electronic components

[0122] The present invention can also provide an electronic component comprising the cured product.

[0123] The alkaline-developable resin composition or dry film of the present invention can be used as protective films, electrical insulating layers, sealants, sealing materials for built-in electronic components, component embedding layers, adhesive layers for fixing electronic components, and the like for printed circuit boards, semiconductor elements, and the like. It is particularly suitable for high-density wiring requiring low dielectric constants and low dielectric loss tangents, electronic components that process high-frequency signals, and electronic components for vehicles and robots that require high-temperature and long-term reliability.

[0124] It should be noted that the electronic components in the present invention refer to components used in electronic circuits, including active components such as printed circuit boards, transistors, light-emitting diodes, laser diodes, etc., as well as passive components such as resistors, capacitors, inductors, connectors, etc.

[0125] Hereinafter, one embodiment of the present invention will be specifically described based on the examples, but it is of course not intended to limit the scope of the invention according to the claims of the present invention.

[0126] In addition, unless otherwise specified, the "parts" and "%" shown are based on mass.

[0127] Example

[0128] [Synthesis Example: Synthesis of Carboxyl Group-Containing Vinyl Ester Resin]

[0129] 1070 g of an o-cresol novolac-type epoxy resin (EPICLONN-695, manufactured by DIC Corporation, softening point 95°C, epoxy equivalent 214, average number of functional groups 7.6) (glycidyl group number (total number of aromatic rings): 5.0 mol), 360 g (5.0 mol) of acrylic acid, and 1.5 g of hydroquinone were added to 600 g of diethylene glycol dibutyl ether, and stirred until uniformly dissolved. Next, 4.3 g of triphenylphosphine was added, and the mixture was heated to 110°C and reacted for 2 hours. The temperature was then raised to 120°C and the reaction was continued for an additional 12 hours. To the resulting reaction solution, 415 g of diethylene glycol dibutyl ether and 456.0 g (3.0 mol) of tetrahydrophthalic anhydride were added, and the mixture was reacted at 110°C for 4 hours. The mixture was then cooled to obtain a carboxyl group-containing vinyl ester resin (varnish). The carboxyl vinyl ester resin (varnish) thus obtained had a solid content concentration of 65% by mass and an acid value of 89 mgKOH / g. Furthermore, the weight-average molecular weight (Mw) of the obtained carboxyl vinyl ester resin was 9000. It should be noted that the weight-average molecular weight of the obtained resin was measured using a high performance liquid chromatograph equipped with an LC-6AD pump manufactured by Shimadzu Corporation and three Shodex (registered trademark) columns KF-804, KF-803, and KF-802 manufactured by Showa Denko K.K.

[0130] [Examples 1 to 6 and Comparative Examples 1 to 5]

[0131] The components shown in Table 1 were pre-mixed in a blender at various blending amounts and then kneaded using a three-roll mill to prepare alkaline-developable resin compositions (two-component systems consisting of a base composition and a curing agent composition) of Examples 1 to 6 and Comparative Examples 1 to 5, respectively.

[0132] [Table 1]

[0133] The components described in Table 1 are as follows.

[0134] *1: Carboxyl vinyl ester resin obtained in Synthesis Example, solid content 65%, solvent content (carbitol acetate (normal solvent)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd.

[0135] *2: Carboxyl vinyl ester resin obtained in Synthesis Example (where only the solvent component was replaced), solid content 65%, solvent component (diethylene glycol dibutyl ether ((F) high boiling point solvent*20)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd.

[0136] *3: Carboxyl vinyl ester resin obtained in Synthesis Example (where only the solvent component was replaced), solid content 65%, solvent component (hexadecanol ester (high boiling point solvent*21)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd.

[0137] *4: Carboxyl vinyl ester resin obtained in Synthesis Example (where only the solvent component was replaced), solid content 65%, solvent content (butyl diglycol acetate (conventional organic solvent*22)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd.

[0138] *5: Carboxyl vinyl ester resin obtained in Synthesis Example (where only the solvent component was replaced), solid content 65%, solvent component (tripropylene glycol n-butyl ether ((F) high boiling point solvent*23)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd.

[0139] *6: Carboxyl vinyl ester resin obtained in Synthesis Example (where only the solvent component was replaced), solid content 65%, solvent component (tetraethylene glycol dimethyl ether ((F) high boiling point solvent*24)) 35%, manufactured by Zhangjiagang DIC Chemical Co., Ltd.

[0140] The difference between *1 to *6: The 6 resins only differ in the type of solvent. The solvent content is 35% and the solid content is the same, which is 65%.

[0141] *7: Organic bentonite: volatile agent, ORBEN M, manufactured by Shiraishi Calcium (Shanghai) International Trading Co., Ltd.

[0142] *8: Green color paste: Base product of 6Y-501, manufactured by TOYOCOLOR CO., LTD.

[0143] *9: Antioxidant: IRGANOX 1010, manufactured by BASF JAPAN LTD.

[0144] *10: Defoaming agent: KSZ-118, manufactured by Zhejiang Shin-Etsu Fine Chemical Co., Ltd.

[0145] *11: Leveling agent: BYK-1790, manufactured by BYK Additives (Shanghai) Co., Ltd.

[0146] *12: Photopolymerization initiator: ITX, isopropylthioxanthone (manufactured by DKSH JAPAN)

[0147] *13: Photopolymerization initiator: #907: α-aminoacetophenone-based photopolymerization initiator (Omnirad 907 manufactured by IGM Resins) (2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one)

[0148] *14: Filler: HD25, talc, manufactured by Fushi (Shanghai) Trading Co., Ltd.

[0149] *15: Filler: A2, barium sulfate, manufactured by Foshan Anyi Nanomaterials Co., Ltd.

[0150] *16: Defoaming agent: DS-100, manufactured by Foshan Nanhai Datian Chemical Co., Ltd.

[0151] *17: Anti-sagging agent: BYK-R606, manufactured by BYK Additives (Shanghai) Co., Ltd.

[0152] *18: Conventional organic solvent: DPM, dipropylene glycol monomethyl ether, manufactured by Shanghai Hongze Chemical (boiling point 190°C)

[0153] *19: Conventional organic solvent: S-150, heavy aromatic solvent naphtha, manufactured by Shanghai Hongze Chemical (boiling point 180°C)

[0154] *20: (F) High boiling point organic solvent: Diethylene glycol dibutyl ether, manufactured by Anhui Lixing New Materials Co., Ltd. (boiling point 254°C)

[0155] *21: High boiling point organic solvent: Hexadecyl alcohol, manufactured by Wuhan Qiaofeng Chemical Technology Co., Ltd. (boiling point 281°C)

[0156] *22: Conventional organic solvent: Diethylene glycol butyl ether acetate, manufactured by Guangzhou Yintian New Materials Co., Ltd. (boiling point 245°C)

[0157] *23: (F) High boiling point organic solvent: Tripropylene glycol n-butyl ether, manufactured by Dow Chemical (Shanghai) Co., Ltd. (boiling point 275°C)

[0158] *24: (F) High boiling point organic solvent: Tetraethylene glycol dimethyl ether, manufactured by Jinan Mingwei Chemical Co., Ltd. (boiling point 275°C)

[0159] *25: Epoxy resin: 128E, manufactured by Nan Ya Plastics Co., Ltd., bisphenol A epoxy resin (solid content 100%)

[0160] *26: Epoxy resin: BNE200D75, bisphenol A novolac epoxy resin, manufactured by Shanghai Hongze Chemical

[0161] *27: Epoxy resin: N-770-75EA, manufactured by DIC Corporation, a novolac-type multifunctional epoxy resin, solid content 75%

[0162] *28: Epoxy resin: TGIC-G, manufactured by Shanghai Xindi Chemical Co., Ltd.

[0163] *29: Photosensitive monomer: DPHA, dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd.

[0164] *30: Melamine: MELAMINE-JC, manufactured by Shanghai Xindi Chemical Co., Ltd.

[0165] *31: Conventional organic solvent: DPM, dipropylene glycol monoether, manufactured by Shanghai Hongze Chemical Co., Ltd.

[0166] The following tests were performed on the obtained base composition, curing agent composition, and alkali-developable resin composition obtained by mixing these in Examples and Comparative Examples.

[0167] <VOCs content>

[0168] According to GB / T 38608-2020, when the expected VOC content (mass fraction) in the alkaline-developable resin composition is greater than 15%, it is determined by the difference method; when the expected VOC content (mass fraction) in the alkaline-developable resin composition is less than or equal to 15%, it is determined by gas chromatography.

[0169] <Air bubbles during printing>

[0170] The alkaline developing resin composition of the above-mentioned embodiment and comparative example is coated on the entire surface by screen printing onto a copper-clad laminate having an opening pattern of φ400μm and a spacing of 600μm and a copper thickness of 3oz (105μm). After standing at room temperature for 30 minutes, it is dried at 80°C for 30 minutes in a hot air circulation drying furnace to prepare a degassing evaluation substrate. The degassing evaluation substrate is observed using a 100x optical microscope to confirm whether bubbles occur in the resin layer filled in the opening pattern portion. The number of opening pattern portions where bubbles occur (number of units) is counted, and the bubble incidence rate of the copper opening pattern portion is evaluated. The evaluation criteria are as follows. The lower the bubble incidence rate, the better the appearance of the cured film.

[0171] ○: Bubble occurrence rate less than 50%

[0172] △: Bubble generation rate is 50% or more

[0173] Bubble generation rate (%) = (number of cells with bubbles / total 100 cells) × 100%

[0174] <Dry to touch>

[0175] On a copper-clad laminated board polished with a polishing roller, each alkaline-developable resin composition of the above-mentioned embodiment and comparative example was applied to the entire surface by screen printing, and dried at 80°C for 30 minutes to prepare a substrate having a resin layer, and the touch dryness of the surface of the resin layer was evaluated.

[0176] ○: No stickiness at all

[0177] △: Slightly sticky

[0178] ×: sticky

[0179] Cured film surface wetting tension (text adhesion)

[0180] The alkaline-developable resin compositions of Examples and Comparative Examples were applied to the entire surface of a copper-clad laminate by screen printing to 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, the alkali-developable resin compositions were exposed to light at 400 mJ / cm using an exposure device equipped with a high-pressure mercury lamp. 2 The entire surface was exposed. Next, the film was developed in a 1 wt% sodium carbonate aqueous solution at a pressure of 0.2 MPa and a temperature of 30°C for 60 seconds. The film was then cured in a hot air circulation drying oven at 150°C for 60 minutes to produce an evaluation substrate with a cured film. The surface tension of the cured film on the evaluation substrate was then measured using a standard dyne pen.

[0181] The higher the surface tension value, the better the hydrophilicity, which is more conducive to text adhesion.

[0182] <Adhesion>

[0183] The alkaline-developable resin compositions of Examples and Comparative Examples were applied to the entire surface of a copper-clad laminate by screen printing to 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, the alkali-developable resin compositions were exposed to light at 400 mJ / cm using an exposure device equipped with a high-pressure mercury lamp. 2 The whole surface was exposed. Then, the substrate was developed in a 1 wt% sodium carbonate aqueous solution, a pressure of 0.2 MPa, and a liquid temperature of 30°C for 60 seconds, and then cured in a hot air circulation drying oven at 150°C for 60 minutes. A UV conveyor oven was used for these substrates at 2000 mJ / cm 2 The substrate was exposed to ultraviolet light to prepare an adhesion evaluation substrate having a cured film.

[0184] Use a grid jig to create 100 1mm squares on the cured film of the evaluation substrate. Then, perform a peel test using scotch tape (3M, 24mm width, adhesion 1.8N / 10mm or more) to determine the peel rate of each 1mm square.

[0185] ○: No shedding

[0186] △: Shedding is less than or equal to 1%

[0187] ×: Shedding greater than 1%

[0188] <Crack resistance>

[0189] The alkaline-developable resin compositions of Examples and Comparative Examples were applied to the entire surface of a substrate having a 2 mm copper wire pattern by screen printing to a thickness of 40 μm, and dried in a hot air circulation drying oven at 80°C for 30 minutes. After cooling to room temperature, the exposure apparatus equipped with a high-pressure mercury lamp was used to expose the substrate at 400 mJ / cm 2 The pattern was exposed, and then developed in a 1 wt% sodium carbonate aqueous solution, a pressure of 0.2 MPa, and a liquid temperature of 30°C for 60 seconds, and then cured in a hot air circulation drying oven at 150°C for 60 minutes. 2 The thermal shock cycle crack resistance evaluation substrate was prepared by irradiating the substrate with ultraviolet light under the conditions of 17 right-angled cured films. Several evaluation substrates prepared as described above were placed in a thermal cycler that cycles between -40°C and 140°C and set for different cycles to conduct a thermal shock cycle test (TCT test). The appearance was then observed at each cycle number, and the maximum number of cycles without cracks in the cured film was recorded (see Figures 1 and 2 for the presence or absence of cracks). The evaluation criteria are shown below.

[0190] ○: No cracks after more than 500 cycles

[0191] ×: Cracks occurred when the number of cycles was less than 500

[0192] The results shown in Table 1 demonstrate that the alkaline-developable resin composition of the present invention exhibits excellent ink properties while reducing VOC content. It is less prone to bubbles when printing on thick copper plates and exhibits improved leveling. The cured product exhibits excellent appearance and further improves adhesion and crack resistance.

[0193] On the other hand, the main agent compositions of Comparative Examples 1 and 2 contained conventional solvents and no high-boiling-point solvents. Consequently, the VOC content exceeded the standard, resulting in a high number of bubbles during printing. While the coating surface exhibited excellent dry-to-touch properties, the surface wetting tension was low (low text adhesion), adhesion was low, and resistance to cracking during thermal cycling was poor. Comparative Example 3, which primarily used conventional solvents and included some high-boiling-point solvents, exhibited a reduced VOC content but still produced a high number of bubbles during printing, a low surface wetting tension (low text adhesion), adhesion was low, and resistance to cracking during thermal cycling was poor. Furthermore, dry-to-touch properties were also reduced.

[0194] The main agent composition of Comparative Example 4 contains a high-boiling point solvent, hexadecyl ester (boiling point 281°C), and the VOCs content is significantly reduced. There are fewer bubbles during printing, and the surface wetting tension of the coating is slightly improved, but the dryness to touch is reduced, the adhesion is low, and the resistance to cracking during hot and cold cycles is poor.

[0195] The main agent composition of Comparative Example 5 contains the conventional solvent diethylene glycol butyl ether acetate (boiling point 245°C), the VOCs content is reduced, there are fewer bubbles during printing, and the surface wetting tension of the coating is slightly improved, but the dryness to touch is reduced, the adhesion is low, and the resistance to cracking during hot and cold cycles is poor.

[0196] In contrast, the alkaline-developable resin compositions of the Examples not only have significantly lower VOCs content (less than 10%), but also produce fewer bubbles during printing, improved surface wetting tension of the cured films, excellent set-to-touch properties, high adhesion, and excellent thermal cycling crack resistance. This demonstrates that the alkaline-developable resin compositions of the present invention pose less environmental risk, exhibit superior ink properties, and produce cured films with improved appearance, text adhesion, adhesion, and crack resistance. These compositions are particularly suitable for use in cured products for printed circuit boards (PCBs) using photolithography, such as solder resists, and electronic components incorporating these cured products.

Claims

1. An alkaline developing resin composition, which is composed of at least a two-component system resin composition, characterized in that: The alkaline developing resin composition comprises: (A) an epoxy resin, (B) a carboxyl group-containing vinyl ester resin, (C) a photopolymerization initiator, (D) a photosensitive monomer, (E) an inorganic filler 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 different resin compositions from the (A) epoxy resin and the (D) photosensitive monomer. The boiling point of the (F) high boiling point solvent is higher than 250°C and lower than 280°C.

2. The alkaline-developable resin composition according to claim 1, characterized in that: The (F) high boiling point solvent is at least one or two or more selected from the group consisting of polyol ethers, polyol esters, organic acid alkyl esters and aliphatic hydrocarbons.

3. The alkaline-developable resin composition according to claim 1 or 2, characterized in that: 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. The alkaline-developable resin composition according to claim 1 or 2, characterized in that: The content of the (F) high boiling point solvent is 40 to 80 parts by mass based on 100 parts by mass of the (B) carboxyl group-containing vinyl ester resin in terms of solid content.

5. The alkaline-developable resin composition according to claim 1 or 2, characterized in that: At least one component of the at least two-component system further comprises a solvent other than the (F) high boiling point solvent.

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

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

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

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

Images