Curable resin composition, dry film, cured product, and printed wiring board

Abstract

PROBLEM TO BE SOLVED: To provide a curable resin composition giving a cured product having a high glass transition temperature and excellent moisture absorption reflow resistance. SOLUTION: A curable resin composition according to the present invention contains a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, and an inorganic filler and is characterized in that the carboxyl group-containing resin contains a specific unit structure and the content of the inorganic filler is from 12 mass% to 80 mass%, in terms of solid content, relative to the total amount of the curable resin composition.

Description

Curable resin composition, dry film, cured product, and printed wiring board

[0001] The present invention relates to a curable resin composition. The present invention also relates to a dry film, a cured product, and a printed wiring board using the curable resin composition.

[0002] In the manufacture of printed wiring boards, curable resin compositions are generally used to form permanent coatings such as solder resists, and dry film-type compositions and liquid compositions have been developed as such curable resin compositions. Among these, due to consideration of environmental issues, alkaline development-type curable resin compositions that use a dilute alkaline aqueous solution as a developer have become mainstream, and several composition systems have been proposed in the past (for example, Patent Document 1).

[0003] Patent Document 1 discloses a photocurable liquid resist ink composition that can be developed with a dilute alkaline solution and contains (A) an active energy ray-curable resin obtained by reacting a reaction product of a novolac epoxy compound and an unsaturated monocarboxylic acid with a saturated or unsaturated polybasic acid anhydride, (B) a photopolymerization initiator, and (C) a diluent, and the photocurable liquid resist ink composition exhibits excellent photocurability and developability.

[0004] Patent Document 2 discloses a carboxyl group-containing photosensitive resin obtained by reacting a reaction product (c) of a novolac phenolic resin (a) and an alkylene oxide (b) with an unsaturated group-containing monocarboxylic acid (d), and then reacting the resulting reaction product (e) with a polybasic acid anhydride (f).

[0005] Japanese Patent Application Laid-Open No. 61-243869 International Publication No. 2002 / 024774

[0006] Conventional solder resists (Patent Document 1) contain impurities in the form of organic chlorines in the carboxyl group-containing resin, which hinders improvement of crosslink density. Although a method for synthesizing a carboxyl group-containing resin that does not contain organic chlorines is known (Patent Document 2), the resin leaves room for improvement in terms of increasing the double bond density in the resin. Furthermore, the present inventors have discovered that the inability to increase the double bond density in the carboxyl group-containing resin results in a low glass transition temperature of the resin, resulting in insufficient moisture absorption reflow resistance of the solder resist.

[0007] The present invention has been made in view of the above problems, and aims to provide a curable resin composition that provides a cured product having a high glass transition temperature and excellent moisture absorption reflow resistance, even when the curable resin is a carboxyl group-containing resin with a reduced chlorine content. Another aim of the present invention is to provide a dry film having a resin layer formed from a dried coating film of the curable resin composition, a cured product of the curable resin composition or the resin layer of the dry film, and a printed wiring board having the cured product.

[0008] Means for Solving the Problems The present inventors have conducted extensive research to achieve the above object, and have found that the above problem can be solved by providing a curable resin composition containing a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, and an inorganic filler, in which the carboxyl group-containing resin has a specific structure and the content of the inorganic filler is adjusted to 12% by mass or more and 80% by mass or less in terms of solid content, relative to the total amount of the curable resin composition.

[0009] That is, the present invention provides the following inventions: [1] A curable resin composition comprising a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, and an inorganic filler, wherein the carboxyl group-containing resin is represented by the following general formulas (I) to (VI): (In the formula, R １１ , R ２１ , R ３１ , R ４１ , R ５１ and R ６１ each independently represents a hydrogen atom or a methyl group, R １２, R ２２ , R ３２ and R ４２ each independently represent a hydrogen atom or an alkyl group, and X represents a single bond or a divalent hydrocarbon group derived from the skeletal structure of a polybasic acid anhydride. In the formula, a, b, c, d, e, and f each represent the number of repetitions of formulas (I) to (VI), and a:b, c:d, and e:f each independently represent a ratio of 100:0 to 0:100, with the proviso that: 5≦a+b+c+d+e+f≦60 is satisfied, 0<(a+b) / (a+b+c+d+e+f)<0.8 is satisfied, 0.2<(c+d) / (a+b+c+d+e+f)<1.0 is satisfied, and (e+f) / (a+b+c+d+e+f)<0.001 is satisfied. ), and the content of the inorganic filler is 12% by mass or more and 80% by mass or less, in terms of solid content, based on the total amount of the curable resin composition. [2] The curable resin composition according to [1], wherein the inorganic filler comprises at least one of silica and barium sulfate. [3] The curable resin composition according to [1] or [2], wherein the content of the carboxyl group-containing resin is 10% by mass or more and 50% by mass or less, in terms of solid content, based on the total amount of the curable resin composition. [4] The curable resin composition according to any one of [1] to [3], wherein the content of the thermosetting component is 5% by mass or more and 30% by mass or less, in terms of solid content, based on the total amount of the curable resin composition. [5] A dry film comprising a first film and a resin layer formed on the first film, the resin layer comprising a dried coating film of the curable resin composition according to any one of [1] to [4]. [6] A cured product obtained by curing the curable resin composition according to any one of [1] to [4]. [7] A cured product obtained by curing the resin layer of the dry film according to [5]. [8] A printed wiring board comprising the cured product according to [6]. [9] A printed wiring board comprising the cured product according to [7].

[0010] According to the present invention, there is provided a curable resin composition that provides a cured product having a high glass transition temperature and excellent moisture absorption reflow resistance. Furthermore, according to the present invention, there are provided a dry film having a resin layer formed from a dried coating film of the curable resin composition, a cured product of the curable resin composition or the resin layer of the dry film, and a printed wiring board having the cured product.

[0011] [Curable Resin Composition] The curable resin composition of the present invention comprises a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, and an inorganic filler. In the curable resin composition, the carboxyl group-containing resin has a specific structure, and the content of the inorganic filler is set to a specific amount, thereby improving the glass transition temperature and moisture absorption reflow resistance of the curable resin composition. While this is not entirely clear, it is speculated as follows. That is, in order to improve the moisture absorption reflow resistance of the curable resin composition, it is effective to use a carboxyl group-containing resin that has a high glass transition temperature and exhibits little change in physical properties during high-temperature moisture absorption treatment. Furthermore, it is speculated that adding a predetermined amount of inorganic filler to the carboxyl group-containing resin can further improve the moisture absorption reflow resistance, but this is merely speculation and is not necessarily limited to this.

[0012] [Definitions] The components constituting the curable resin composition of the present invention are described below. In this specification, (meth)acrylic acid is a general term referring to acrylic acid, its corresponding methacrylic acid, and mixtures thereof, and (meth)acrylate is a general term referring to acrylates, its corresponding methacrylates, and mixtures thereof. Similarly, (meth)acryloyl group is a general term referring to acryloyl groups and their corresponding methacryloyl groups, and (meth)acryloxy group is a general term referring to acryloxy groups and their corresponding methacryloxy groups. In this specification, the term "reaction raw material" refers to a compound used to obtain a target compound through a chemical reaction such as synthesis or decomposition, and partially constitutes the chemical structure of the target compound. Substances that serve as chemical reaction aids, such as solvents and catalysts, are excluded. In this specification, the term "unit structure" refers to a (repeating) unit of a chemical structure formed during a reaction or polymerization. In other words, in the product compound formed by a reaction or polymerization, a partial structure other than the structure of the chemical bonds involved in the reaction or polymerization, i.e., a residue.

[0013] (Carboxyl Group-Containing Resin) The carboxyl group-containing resin contained in the curable resin composition of the present invention is a resin represented by the following general formulas (I) to (VI): (In the formula, R １１ , R ２１ , R ３１ , R ４１ , R ５１ and R ６１ each independently represents a hydrogen atom or a methyl group, R １２ , R ２２ , R ３２ , and R ４２each independently represent a hydrogen atom or an alkyl group, X represents a single bond or a divalent hydrocarbon group derived from the skeletal structure of a polybasic acid anhydride. In the formula, a, b, c, d, e, and f each represent the number of repetitions of formulas (I) to (VI), and a:b, c:d, and e:f each independently represent a ratio of 100:0 to 0:100, with the proviso that: 5≦a+b+c+d+e+f≦60 is satisfied, 0<(a+b) / (a+b+c+d+e+f)<0.8 is satisfied, 0.2<(c+d) / (a+b+c+d+e+f)<1.0 is satisfied, and (e+f) / (a+b+c+d+e+f)<0.001 is satisfied.

[0014] The carboxyl group-containing resin used in the present invention satisfies the condition that the number of repeating units of the structural units represented by formulas (I) to (VI) satisfies 5≦a+b+c+d+e+f≦60, preferably 5 to 55, and even more preferably 5 to 50. When the sum of the number of repeating units is less than the upper limit, the developability and resolution are improved. When the sum of the number of repeating units is greater than the lower limit, the glass transition temperature of the resin is increased, thereby improving insulation reliability. The sum of the number of repeating units (a+b+c+d+e+f) can be determined, for example, from the molar concentration of benzene rings quantified by NMR analysis using the internal standard method.

[0015] Since the carboxyl group-containing resin provides a curable resin composition having excellent alkali developability and high photosensitivity, and capable of forming a cured product having excellent heat resistance and substrate adhesion, the content of unit structures (I) and (II) containing neither a carboxyl group nor a chlorine atom satisfies 0<(a+b) / (a+b+c+d+e+f)<0.8, and is preferably 0.4 or more and 0.75 or less. Note that (a+b) can be calculated by subtracting (c+d) and (e+f) calculated below from (a+b+c+d+e+f) calculated above.

[0016] The carboxyl group-containing resin has excellent alkali developability and high photosensitivity, and can form a cured product having excellent heat resistance and substrate adhesion. Therefore, the content of the carboxyl group-containing unit structures (III) and (IV) satisfies 0.2 < (c + d) / (a ​​+ b + c + d + e + f) < 1.0, preferably 0.25 or more and 0.6 or less. The acid value of the carboxyl group-containing resin is preferably in the range of 40 to 140 mg KOH / g, more preferably 50 to 120 mg KOH / g. In the present invention, the acid value of the carboxyl group-containing resin is a value measured by the neutralization titration method of JIS K 0070 (1992), and the (c + d) can be calculated by dividing the acid value by the molar mass of KOH (56,105 mg / mol).

[0017] The carboxyl group-containing resin reduces the environmental load and exhibits high insulating reliability when cured, so it is more preferable that the content of the chlorine atom-containing unit structures (V) and (VI) satisfies (e + f) / (a ​​+ b + c + d + e + f) < 0.001 and is 0.0005 or less. When the carboxyl group-containing resin is used in the curable resin composition of the present invention, particularly in a solder resist resin material, an insulating material, a resist member, or the like, it exhibits high insulating reliability and high heat resistance when cured, and can exhibit excellent thermal shock resistance. Generally, in a printed wiring board having conductive wiring or electronic components attached on or inside a substrate made of an insulating material, when a voltage is applied between the electrodes of the board, the anode portion of the wiring pattern receives electrons, making it easy for metal ions to dissolve from the surface of the anode portion into moisture or ionic substances contained on the board surface or inside the base material. When the metal ions dissolve in the water or ionic substance, they migrate to the cathode side due to Coulomb force caused by the electric field and can be regenerated as metal (so-called dendrites) through electron exchange. If dendrites grow large due to the ionization and dissolution of the metal constituting the electrode, this can cause insulation degradation. In particular, if a certain amount or more of ionic components (e.g., halogen atoms such as chlorine atoms) contained in the resist material or base material are present in the water or ionic substance, metal ions are more likely to dissolve, facilitating migration and resulting in reduced insulation reliability. However, the carboxyl group-containing resin has a reduced chlorine atom content, which is believed to suppress or prevent such a decrease in insulation reliability. Furthermore, the reduced halogen content is believed to reduce environmental impact. As described below, when a compound having an epoxy group is used as a component of a curable resin composition, the epoxy group is introduced into the desired compound industrially using a chlorine atom-containing compound such as epichlorohydrin. Therefore, the amount of chlorine atoms remaining in the system cannot be ignored in order to maintain high insulation reliability.The (e+f) can be calculated by dividing the weight chlorine concentration (ppm) determined by the following method (combustion tube combustion method) by the molar mass of chlorine atoms (35.45 g / mol).

[0018] In this specification, the method for calculating the content of chlorine atoms in the carboxyl group-containing resin, the (meth)acrylate compound (B) having an epoxy group, or the curable resin composition is as follows. The content of chlorine atoms in the carboxyl group-containing resin, the (meth)acrylate compound (B) having an epoxy group, or the curable resin composition was measured by burning and decomposing the carboxyl group-containing resin or the curable resin composition at high temperature using a combustion tube combustion method, absorbing the decomposition gas into an absorption liquid, and quantifying it by ion chromatography. The absorption liquid used was ultrapure water containing hydrogen peroxide solution and hydrazine hydrate. The ion chromatography was performed using an ion chromatograph "Ion Chromatograph ICS-1500 Model (detector: electrical conductivity meter)" manufactured by Thermo Fisher Scientific Inc. and an ion chromatography column "AS-12A manufactured by Thermo Fisher Scientific Inc.." The eluent was 0.3 mM sodium bicarbonate (NaHCO ). ３ ) aqueous solution and 2.7 mM sodium carbonate (Na ２ CO ３ ) aqueous solution, and the flow rate was 1.5 mL / min.

[0019] In the present invention, means for making the content of chlorine-containing unit structures (e+f) / (a+b+c+d+e+f) in the carboxyl group-containing resin less than 0.001 include (1) using compounds that do not contain chlorine atoms as the components constituting the carboxyl group-containing resin and as raw materials, catalysts, solvents, and additives used to synthesize the components, and (2) performing a purification step to remove chlorine atoms from the components constituting the carboxyl group-containing resin and as raw materials, catalysts, solvents, and additives used to synthesize the components. In the present invention, means for making the content of chlorine-containing unit structures (e+f) / (a+b+c+d+e+f) in the carboxyl group-containing resin less than 0.001 preferably include at least one of purification using preparative HPLC under known conditions and using compounds that do not contain chlorine atoms as the components constituting the carboxyl group-containing resin and as raw materials, catalysts, solvents, and additives used to synthesize the components. As a means of using compounds that do not contain chlorine atoms as the components constituting the carboxyl group-containing resin and the raw materials, catalysts, solvents, and additives used to synthesize these components, it is preferable to use a (meth)acrylate compound (B) having an epoxy group with a chlorine atom content of 10 mass ppm or less, preferably below the detection limit, as described below. More specifically, the (meth)acrylate compound (B) having an epoxy group with a chlorine atom content of 10 mass ppm or less, preferably below the detection limit, has a chemical structure similar to that of a compound synthesized by reacting epichlorohydrin with a (meth)acrylate compound (b1) (e.g., an alkali metal salt of (meth)acrylic acid, (meth)acrylic acid) and glycidylating it. Furthermore, the (meth)acrylate compound (B) having an epoxy group has a chemical structure similar to that of a compound obtained by transesterification of an epoxy group- and hydroxyl group-containing compound (e.g., glycidol) with (meth)acrylic acid, etc. From an industrial viewpoint, the former reaction shows a higher yield, but since epichlorohydrin has a chlorine atom in the molecule, the obtained (meth)acrylate compound (B) having an epoxy group contains chlorine compounds as by-products at a concentration of about 500 ppm to several percent.Therefore, the (meth)acrylate compound (B) having an epoxy group in the present invention is preferably a compound obtained by reacting an epoxy group- and hydroxyl group-containing compound (e.g., glycidol) with (meth)acrylic acid as reaction raw materials, thereby making it possible to make the content of chlorine atom-containing unit structures in the carboxyl group-containing resin (e+f) / (a+b+c+d+e+f) less than 0.001.

[0020] [Method for producing carboxyl group-containing resin] The carboxyl group-containing resin used in the present invention can be produced using a phenolic resin (A), a (meth)acrylate compound (B) having an epoxy group, and a polybasic acid anhydride (C) as reaction raw materials (1). Hereinafter, the phenolic resin (A), the (meth)acrylate compound (B) having an epoxy group, and the polybasic acid anhydride (C) will be described.

[0021] (Phenol-based Resin (A)) The phenol-based resin (A) in the present invention can be any known or commonly used resin as long as it has a phenolic hydroxyl group. Examples of such resins include novolak resins which are polycondensates of phenols (phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.) with formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, o-hydroxybenzaldehyde, p-hydroxyacetophenone, o-hydroxyacetophenone, and furfural; reaction products of phenol or cresol with a phenylenedimethylol compound, a dimethoxymethyl compound, or a methyl halide compound; and reaction products of phenol or cresol with bischloromethylbiphenyl, bismethoxymethylbiphenyl, ... Examples of the phenolic resin (A) include a reaction product of phenol with benzenediisopropanol, benzenediisopropanol dimethyl ether, or benzenebis(chloroisopropane), a phenol aralkyl resin, which is a reaction product of phenol with benzenediisopropanol, benzenediisopropanol dimethyl ether, or benzenebis(chloroisopropane), and modified products thereof; halogenated bisphenols such as tetrabromobisphenol A; condensates of terpenes and phenols; dicyclopentadiene-phenol addition type resins; cresol aralkyl resins; phenol trimethylolmethane resins; tetraphenylolethane resins; aminotriazine-modified phenolic resins; and alkoxy group-containing aromatic ring-modified novolac resins (polyhydric phenol compounds in which a phenol nucleus and an alkoxy group-containing aromatic ring are linked by formaldehyde). Among these, the phenolic resin (A) may be any of novolac type phenolic resins, resol type phenolic resins, or other phenolic resins, but novolac type phenolic resins are preferred from the viewpoint of obtaining the carboxyl group-containing resin that exhibits high insulation reliability, high heat resistance, and excellent thermal shock resistance. The novolac type phenolic resin is preferably a resin obtained by reacting an [aldehyde compound (a1)] / [phenolic compound (a2)] in a molar ratio of 0.3 to 1.0, and the resol type phenolic resin is preferably a resin obtained by reacting an [aldehyde compound (a1)] / [phenolic compound (a2)] in a molar ratio of 1.0 to 2.5.The method for producing the phenolic resin (A) of the present invention includes, for example, a step of reacting an aldehyde compound (a1) and a phenolic compound (a2) using an acid or alkali as a catalyst at 40 to 150°C for 1 to 5 hours, a step of removing residual water from the reaction system through a normal pressure or reduced pressure dehydration step, and a step of dissolving the condensate in the reaction system in a solvent such as methanol. In the removal operation of the step of removing residual water from the reaction system, the content of residual water is not particularly limited.

[0022] <Novolac-type phenolic resin> In the present invention, the novolac-type phenolic resin is not particularly limited, and one type may be used alone or two or more types may be used in combination. In the present invention, the number average molecular weight of the novolac-type phenolic resin is preferably 200 to 10,000, and more preferably 1,000 to 7,000.

[0023] The novolac phenolic resin of the present invention is preferably a resin prepared by reacting an aldehyde compound (a1) and a phenolic compound (a2) as raw materials (2). If necessary, the raw materials (2) may contain one or more compounds selected from the group consisting of catalysts, organic solvents, acids, and additives. Thus, a novolac phenolic resin can be obtained by reacting the aldehyde compound (a1) with the phenolic compound (a2) in a molar ratio of 0.3 to 1.0 in the presence of a catalyst. Examples of the aldehyde compound (a1) include formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine, furfural, glyoxal, n-butylaldehyde, caproaldehyde, allylaldehyde, benzaldehyde, crotonaldehyde, acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde, etc. These aldehyde compounds (a1) may be used alone or in combination of two or more.Examples of the phenol compound (a2) include alkylphenols such as phenol, cresol (o-cresol, m-cresol, or p-cresol), xylenol (2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, or 3,5-xylenol), ethylphenol (o-ethylphenol, m-ethylphenol, or p-ethylphenol), butylphenol (isopropylphenol, butylphenol, p-t-butylphenol), octylphenol, p-nonylphenol, and p-cumylphenol; polyhydric phenols such as resorcinol, catechol, hydroquinone, and trihydroxybenzene; and bisphenols. Examples of the phenol compound (a2) include bisphenols such as bisphenol A, bisphenol F, bisphenol S, bisphenol E, thiobisphenol, bis(hydroxyphenyl)ether, dihydroxybenzophenone, and bisphenolfluorene; halogenophenols such as fluorophenol, chlorophenol, bromophenol, and iodophenol; mono-substituted phenols such as p-phenylphenol, aminophenol, nitrophenol, dinitrophenol, and trinitrophenol; and naphthols such as 1-naphthol, 2-naphthol, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, and trihydroxynaphthalene. These phenol compounds (a2) may be used alone or in combination of two or more.

[0024] In the production of the novolac phenolic resin of the present invention, acids can be used, such as formic acid, hydrochloric acid, phosphoric acid, sulfuric acid, paratoluenesulfonic acid, phenolsulfonic acid, etc. The acids may be blended with the reaction raw material (2).

[0025] Examples of the catalyst include metal salts such as zinc acetate and manganese borate, and metal oxides such as lead oxide and zinc oxide. These catalysts can be used alone or in combination of two or more. Furthermore, when producing the novolac phenolic resin, additives such as furfural, urea, melamine, acetoguanamine, and benzoguanamine can also be used in combination, if necessary. The novolac phenolic resin is preferably one in which the amount of residual catalyst has been reduced by washing with water or the like, more preferably 50 ppm or less, even more preferably 10 ppm or less, even more preferably 0.1 ppm or less, and particularly preferably 0.005 ppm or less.

[0026] For example, the reaction of the aldehyde compound (a1) with the phenol compound (a2) may be carried out in the presence of an organic solvent, or an organic solvent may be added to the resulting reaction product. Examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene, glycols such as ethylene glycol and propylene glycol, polyether glycols which are polymers thereof, cellosolves, carbitols, and aliphatic alcohols such as methanol.

[0027] <Resol-Type Phenol Resin> The resol-type phenolic resin of the present invention is preferably a resin prepared by reacting an aldehyde compound (a1) and a phenol compound (a2) as reaction raw materials (3), similar to the novolac-type phenolic resin described above. If necessary, the reaction raw material (3) may contain one or more compounds selected from the group consisting of alkaline catalysts, organic solvents, and additives. This allows the aldehyde compound (a1) to react in the presence of a catalyst at a molar ratio of the phenol compound (a2) to the aldehyde compound (a1) of 1.0 to 4.0, thereby obtaining a resol-type phenolic resin. When synthesizing the resol-type phenolic resin of the present invention, the molar ratio of the phenol compound (a2) to the aldehyde compound (a1) is preferably in the range of 1.0 to 4.0, more preferably 1.5 to 3.0, because this reduces the amount of unreacted material remaining in the reaction product, suppresses foaming, and provides good curability. In the present invention, the number-average molecular weight of the resol-type phenolic resin is preferably 200 to 10,000, more preferably 1,000 to 5,000. Examples of the alkaline catalyst include alkali hydroxides such as caustic soda, alkaline earth metal oxides, ammonia, aliphatic amines, aromatic amines, alkanolamines, and the like, as well as zinc acetate and zinc octoate, which are catalysts used in the production of high-ortho and benzylic types. More specific examples include alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide; alkaline earth metal oxides and hydroxides such as calcium, magnesium, and barium; primary amines such as ammonia and monoethanolamine; secondary amines such as diethanolamine; tertiary amines such as trimethylamine, triethylamine, triethanolamine, and diazabicycloundecene; and alkaline substances such as sodium carbonate and hexamethylenetetramine. These alkaline catalysts can be used alone or in combination. Among these alkaline catalysts, sodium hydroxide, potassium hydroxide, barium hydroxide, and calcium hydroxide are preferred because of their excellent catalytic activity. The alkaline catalyst may be added to the reaction raw material (3) before the reaction or during the reaction.The organic solvents and additives that can be added to the reaction raw material (3) are the same as those that can be added to the reaction raw material (2).

[0028] <Other Phenolic Resins> The other phenolic resins of the present invention may be resins prepared by reacting a compound (a5) having a phenolic hydroxyl group with an aldehyde compound (a1) as reaction raw materials. If necessary, the reaction raw materials may contain one or more selected from the group consisting of the catalyst, organic solvent, acid, and additive. In this way, the other phenolic resins can be obtained by reacting the aldehyde compound (a1) with the compound (a5) having a phenolic hydroxyl group in the presence of a catalyst at a molar ratio of 0.3 to 1.0. The other phenolic resins do not include the novolac-type phenolic resins and resol-type phenolic resins.

[0029] ((Meth)acrylate Compound (B) Having Epoxy Group) The carboxyl group-containing resin used in the present invention is a glycidyl (meth)acrylate or a (meth)acrylate in which the α carbon in the acrylic group is an alkyl group R ２ The structure (H ２ C=C(-R ２)-C(═O)-OR (R is an optional substituent). Hereinafter, the above-mentioned substituted structures are also referred to as (meth)acrylates. In addition to glycidyl (meth)acrylates, (meth)acrylate compounds having an additional epoxy group may also be used. As long as the molecular structure contains a (meth)acryloyl group and an epoxy group, the specific structure is not particularly limited, and a wide variety of compounds can be used. Examples of such compounds include (meth)acrylate monomers having a glycidyl group, such as 4-hydroxybutyl (meth)acrylate glycidyl ether and epoxycyclohexylmethyl (meth)acrylate; and mono(meth)acrylates of diglycidyl ether compounds, such as dihydroxybenzene diglycidyl ether, dihydroxynaphthalene diglycidyl ether, biphenol diglycidyl ether, and bisphenol diglycidyl ether. Among these, the carboxyl group-containing resin of the present invention uses glycidyl (meth)acrylates, and it is preferable to use 4-hydroxybutyl (meth)acrylate glycidyl ether or epoxycyclohexylmethyl (meth)acrylate in addition to the carboxyl group-containing resin. These (meth)acrylate compounds having an epoxy group can be used alone or in combination of two or more.

[0030] In the present invention, the content of chlorine atoms contained in the (meth)acrylate compound (B) having an epoxy group is preferably 500 ppm by mass or less, more preferably 1 ppm by mass or more and 100 ppm by mass or less, and even more preferably 1 ppm by mass or more and 100 ppm by mass or less. By having the chlorine atom content of the (meth)acrylate compound (B) having an epoxy group, which is a component of the reaction raw material (1) of the carboxyl group-containing resin in the present invention, be 100 ppm by mass or less, the chlorine atom content of the resin can be 100 ppm by mass or less. A common method for synthesizing glycidyl (meth)acrylate is a method using epichlorohydrin as a raw material. These methods can be broadly classified into the following two methods. The first method is a method in which epichlorohydrin and an alkali metal (meth)acrylate salt are reacted in the presence of a catalyst to synthesize glycidyl (meth)acrylate. The second method is to react epichlorohydrin with (meth)acrylic acid in the presence of a catalyst, followed by a ring-closure reaction in an aqueous alkaline solution to synthesize glycidyl (meth)acrylate. However, in either method, epichlorohydrin contains chlorine atoms in the molecule. Therefore, if the synthesis method of the (meth)acrylate compound (B) having an epoxy group in the present invention involves reacting epichlorohydrin with the (meth)acrylate compound (b1) and glycidylating it, since epichlorohydrin contains chlorine atoms in the molecule, it is believed that the resulting (meth)acrylate compound (B) having an epoxy group will contain chlorine compounds as by-products at a concentration of about 500 ppm to several percent. Therefore, a carboxyl group-containing resin containing the (meth)acrylate compound (B) having an epoxy group as a component of the reaction raw material (1) may also contain chlorine atoms at a concentration of about 500 ppm to several percent or less by mass ppm. Similarly, when the carboxyl group-containing resin is selected as a curing agent for a curable resin composition, the presence of chlorine atoms or chlorine compounds as impurities may affect the insulation reliability.Therefore, when the (meth)acrylate compound (B) having an epoxy group is synthesized using epichlorohydrin in the present invention, it is preferable to reduce the content of chlorine atoms contained in the (meth)acrylate compound (B) having an epoxy group to 100 ppm by mass or less by the above-mentioned purification method.

[0031] As the (meth)acrylate compound (b1), glycidyl (meth)acrylates are used. Other (meth)acrylate compounds may also be used without any particular limitation as long as they have a (meth)acryloyl group, and examples thereof include aliphatic mono(meth)acrylate compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and octyl (meth)acrylate; cyclohexyl (meth)acrylate; Alicyclic mono(meth)acrylate compounds such as acrylate, isobornyl (meth)acrylate, and adamantyl mono(meth)acrylate; heterocyclic mono(meth)acrylate compounds such as tetrahydrofurfuryl acrylate; benzyl (meth)acrylate, phenyl (meth)acrylate, phenylbenzyl (meth)acrylate, phenoxy (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxyethoxyethyl (meth)acrylate, 2-hydro Mono(meth)acrylate compounds such as aromatic mono(meth)acrylate compounds such as 3-phenoxypropyl (meth)acrylate, phenoxybenzyl (meth)acrylate, benzyl benzyl (meth)acrylate, and phenylphenoxyethyl (meth)acrylate; (poly)oxyalkylene-modified mono(meth)acrylate compounds in which a polyoxyalkylene chain such as a (poly)oxyethylene chain, a (poly)oxypropylene chain, or a (poly)oxytetramethylene chain has been introduced into the molecular structure of the various mono(meth)acrylate monomers mentioned above; lactone-modified mono(meth)acrylate compounds in which a (poly)lactone structure has been introduced into the molecular structure of the various mono(meth)acrylate compounds mentioned above; aliphatic di(meth)acrylate compounds such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate;Alicyclic di(meth)acrylate compounds such as 1,4-cyclohexanedimethanol di(meth)acrylate, norbornane di(meth)acrylate, norbornane dimethanol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, and tricyclodecane dimethanol di(meth)acrylate; aromatic di(meth)acrylate compounds such as biphenol di(meth)acrylate and bisphenol di(meth)acrylate; and compounds having a (poly)oxyethylene group in the molecular structure of the above-mentioned various di(meth)acrylate compounds. polyoxyalkylene-modified di(meth)acrylate compounds in which a (poly)oxyalkylene chain such as a (poly)ethylene chain, a (poly)oxypropylene chain, or a (poly)oxytetramethylene chain has been introduced; lactone-modified di(meth)acrylate compounds in which a (poly)lactone structure has been introduced into the molecular structure of the above-mentioned various di(meth)acrylate compounds; aliphatic tri(meth)acrylate compounds such as trimethylolpropane tri(meth)acrylate and glycerin tri(meth)acrylate; (Poly)oxyalkylene-modified tri(meth)acrylate compounds in which a (poly)oxyalkylene chain such as a (poly)oxyethylene chain, a (poly)oxypropylene chain, or a (poly)oxytetramethylene chain has been introduced into the structure; lactone-modified tri(meth)acrylate compounds in which a (poly)lactone structure has been introduced into the molecular structure of the aliphatic tri(meth)acrylate compounds; pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, aliphatic poly(meth)acrylate compounds having tetrafunctional or more functional groups such as acrylate; (poly)oxyalkylene-modified poly(meth)acrylate compounds having tetrafunctional or more functional groups in which a (poly)oxyalkylene chain such as a (poly)oxyethylene chain, a (poly)oxypropylene chain, or a (poly)oxytetramethylene chain has been introduced into the molecular structure of the aliphatic poly(meth)acrylate compound; and lactone-modified poly(meth)acrylate compounds having tetrafunctional or more functional groups in which a (poly)lactone structure has been introduced into the molecular structure of the aliphatic poly(meth)acrylate compound.(meth)acrylate compounds having a hydroxyl group, such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, trimethylolpropane (meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol (meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane (meth)acrylate, ditrimethylolpropane di(meth)acrylate, and ditrimethylolpropane tri(meth)acrylate; (meth)acrylate compounds having a hydroxyl group, such as (poly)oxyethylene chains, (poly)oxypropylene chains, (poly)oxypropylene chains, lactone modified compounds in which a (poly)lactone structure has been introduced into the molecular structure of the above-mentioned (meth)acrylate compound having a hydroxyl group; (meth)acrylate compounds having an isocyanate group such as 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, and 1,1-bis(acryloyloxymethyl)ethyl isocyanate; (meth)acrylate compounds having an epoxy group such as (meth)acrylate monomers having a glycidyl group such as 4-hydroxybutyl(meth)acrylate glycidyl ether and epoxycyclohexylmethyl(meth)acrylate, and mono(meth)acrylate products of diglycidyl ether compounds of hydroxybenzene diglycidyl ether, dihydroxynaphthalene diglycidyl ether, biphenol diglycidyl ether, and bisphenol diglycidyl ether. The various (meth)acrylate compounds (b1) can be used alone or in combination of two or more. Among the above examples, the (meth)acrylate compound (b1) suitable for the present invention is preferably a compound that reacts with epichlorohydrin.

[0032] In this specification, the method for calculating the content of chlorine atoms in the (meth)acrylate compound (B) having an epoxy group is the same as above, using ion chromatography by the combustion tube combustion method, and therefore the details are omitted here.

[0033] The amount of the (meth)acrylate compound (B) having an epoxy group used is preferably in the range such that the number of moles of the epoxy groups in the (meth)acrylate compound (B) having an epoxy group is 0.9 to 1.2 moles, and more preferably 0.95 to 1.1 moles, per mole of the phenolic hydroxyl groups in the phenolic resin (A), because a curable resin composition having excellent alkali developability and capable of forming a cured product excellent in elongation, adhesion, and dielectric properties can be obtained.

[0034] In the present invention, another method for reducing the chlorine atoms contained in the (meth)acrylate compound (B) having an epoxy group or the carboxyl group-containing resin to 100 mass ppm or less is preferably a production method using a transesterification reaction between an epoxy group- and hydroxyl group-containing compound such as glycidol and a (meth)acrylic acid ester such as the (meth)acrylate compound (b1). As a method for producing the (meth)acrylate compound (B) having an epoxy group by the transesterification reaction between the epoxy group- and hydroxyl group-containing compound such as glycidol and a (meth)acrylic acid ester such as the (meth)acrylate compound (b1) (e.g., methyl (meth)acrylate, ethyl (meth)acrylate), a known method can be used, in which the reaction is carried out in the presence of a basic catalyst while removing the by-product alkanol from the system by distillation. After completion of the reaction, the catalyst used in the reaction can be removed from the system by operations such as filtration or washing with water before purifying the target product. As the epoxy group- and hydroxyl group-containing compound, hydroxyalkene oxides (epoxyalkanols) are preferred. For example, hydroxyalkene oxides having 3 to 10 carbon atoms such as 2,3-epoxypropanol (glycidol) and 2,3-epoxybutanol; and hydroxycycloalkene oxides having 4 to 10 carbon atoms such as 2,3-epoxycyclobutanol and 2,3-epoxycyclopentanol are preferred.

[0035] The ratios a:b, c:d, and e:f of the structural units of the carboxyl group-containing resin used in the present invention are each independently 100:0 to 0:100. In this reaction system, the (meth)acrylate compound (B) having an epoxy group can be added to the phenolic resin in two forms: β-addition, which is formed by cleavage of an unsubstituted β-carbon in the epoxide, and α-addition, which is formed by cleavage of a substituted α-carbon. The reaction process between a phenolic resin and epichlorohydrin or a glycidyl (meth)acrylate, and the reaction process between the reaction product of the phenolic resin and a glycidyl (meth)acrylate and a polybasic acid anhydride are shown below for both α-addition and β-addition. (In the formula, R ７are independently a hydrogen atom or a methyl group. 1 is independently an integer of 0 or greater. X is a single bond or a divalent hydrocarbon group derived from the skeletal structure of a polybasic acid anhydride, as described below. This is because, in asymmetric epoxides having the above substituents, β-addition is likely to occur in the presence of a basic catalyst, and α-addition is likely to occur in the presence of an acidic catalyst. In particular, in the carboxyl group-containing resin used in the present invention, β-addition can be made more likely to occur by using, for example, a basic catalyst, as described below.

[0036] (Polybasic Acid Anhydride (C)) By including a unit structure derived from the polybasic acid anhydride (C) as the unit structure constituting the carboxyl group-containing resin of the present invention, the carboxyl group-containing resin obtained as described above can exhibit excellent insulation reliability, heat resistance, and cold-heat shock resistance when cured. Examples of the polybasic acid anhydride (C) in the present invention include saturated polybasic acid anhydrides and unsaturated polybasic acid anhydrides. In the present invention, the saturated polybasic acid anhydride means a polybasic acid anhydride that does not have a carbon-carbon double bond, and the unsaturated polybasic acid anhydride means a polybasic acid anhydride that has a carbon-carbon double bond.

[0037] Examples of the saturated polybasic acid anhydride include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,2,3,4-butanetetracarboxylic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, cyclohexanetricarboxylic acid, cyclohexanetetracarboxylic acid, bicyclo[2.2.1]heptane-2,3-dicarboxylic acid, methylbicyclo[2.2.1]heptane-2,3-dicarboxylic acid, etc. Among these, hexahydrophthalic anhydride (hexahydroisobenzofuran-1,3-dione), methylhexahydrophthalic anhydride (3-methyl-8-oxabicyclo[4.3.0]nonane-7,9-dione), etc. are more preferred.

[0038] Examples of the unsaturated polybasic acid anhydride include acid anhydrides of maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, tetrahydrophthalic acid, phthalic acid, trimellitic acid, pyromellitic acid, naphthalenedicarboxylic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, biphenyldicarboxylic acid, biphenyltricarboxylic acid, biphenyltetracarboxylic acid, benzophenonetetracarboxylic acid, and 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid.

[0039] In the carboxyl group-containing resin used in the present invention, the divalent hydrocarbon group derived from the skeletal structure of the polybasic acid anhydride is preferably selected from the group consisting of the structures shown below. (n is 1 to 8, m1 is 0 to 2, m2 is 0 to 2, m3 is 0 or 1, m1' is 0 to 2, m2' is 0 to 2, m3' is 0 or 1, m is 0 to 2, m' is 0 to 2, and m'' is 0 to 2. R α is a hydrogen atom or a methyl group. * is a bond, and in a linking group having three or more bonds, any two positions serve as bonds for X, and the remaining * positions are substituted with *-COOH groups and / or their anhydride groups (*-C(=O)-O-C(=O)-*).

[0040] These polybasic acid anhydrides may be used alone or in combination of two or more thereof. Among these, saturated polybasic acid anhydrides are preferred, and saturated polybasic acid anhydrides having an alicyclic structure are more preferred, because they can give carboxyl group-containing resins capable of forming cured products having high photosensitivity, excellent alkali developability, and excellent heat resistance, heat yellowing resistance, and reflectivity.

[0041] The amount of the polybasic acid anhydride (C) used is preferably in the range of 0.20 to 1.05 mol, more preferably 0.25 to 0.95 mol, even more preferably 0.30 to 0.95 mol, and still more preferably 0.30 to 0.90 mol, relative to 1 mol of the phenolic hydroxyl group in the phenolic resin (A), because a curable resin composition having excellent alkali developability and capable of forming a cured product excellent in elongation, adhesion, and dielectric properties can be obtained.

[0042] (Other Compounds) The carboxyl group-containing resin may contain, as necessary, other compounds as reaction raw materials (1) other than the phenolic resin (A), the (meth)acrylate compound (B) having an epoxy group, and the polybasic acid anhydride (C). Examples of the other compounds include unsaturated monobasic acid anhydrides. Examples of the unsaturated monobasic acid anhydrides include acrylic acid anhydride and methacrylic acid anhydride. These unsaturated monobasic acid anhydrides can be used alone or in combination of two or more.

[0043] The total mass proportion of the phenolic resin (A), the (meth)acrylate compound (B) having an epoxy group, and the polybasic acid anhydride (C) in the raw materials (solid content) of the carboxyl group-containing resin is preferably 70 mass% or more, more preferably 80 mass% or more and 100 mass% or less, and even more preferably 80 mass% or more and 99 mass% or less.

[0044] The method for producing the carboxyl group-containing resin is not particularly limited, and any method may be used. For example, the carboxyl group-containing resin may be produced by a method in which all of the reaction raw materials containing the phenolic resin (A), the (meth)acrylate compound (B) having an epoxy group, and the polybasic acid anhydride (C) are reacted at once, or by a method in which the reaction raw materials are reacted sequentially. Among these, a method in which the phenolic resin (A) and the (meth)acrylate compound (B) having an epoxy group are first reacted in the presence of a basic catalyst at a temperature range of 80 to 140°C, and then the polybasic acid anhydride (C) is added and reacted at a temperature range of 80 to 140°C is preferred because it is easy to control the reaction.

[0045] The reaction of the phenolic resin (A), the (meth)acrylate compound (B) having an epoxy group, and the polybasic acid anhydride (C) can be carried out in an organic solvent, if necessary, and a polymerization inhibitor or an antioxidant can also be used, if necessary.

[0046] Examples of the basic catalyst include N-methylmorpholine, pyridine, 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), 1,5-diazabicyclo[4.3.0]nonene-5 (DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO), tri-n-butylamine or dimethylbenzylamine, trimethylamine, triethylamine, triisopropylamine, tributylamine, trioctylamine, butylamine, octylamine, monoethanolamine, diene Ethanolamine, triethanolamine, imidazole, 1-methylimidazole, 2-ethyl-4-methylimidazole, 2,4-dimethylimidazole, 1,4-diethylimidazole, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(N-phenyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropylmethyldimethoxysilane, tetramethylammonium hydroxy quaternary ammonium salts such as trioctylmethylammonium chloride and trioctylmethylammonium acetate; phosphine compounds such as trimethylphosphine, tributylphosphine and triphenylphosphine; phosphonium salts such as tetramethylphosphonium chloride, tetraethylphosphonium chloride, tetrapropylphosphonium chloride, tetrabutylphosphonium chloride, tetrabutylphosphonium bromide, trimethyl(2-hydroxypropyl)phosphonium chloride, triphenylphosphonium chloride and benzylphosphonium chloride; organic tin compounds such as dibutyltin dilaurate, octyltin trilaurate, octyltin diacetate, dioctyltin diacetate, dioctyltin dineodecanoate, dibutyltin diacetate, tin octoate and 1,1,3,3-tetrabutyl-1,3-dodecanoyldistannoxane; organic metal compounds such as zinc octoate and bismuth octoate; inorganic tin compounds such as tin octoate; and inorganic metal compounds. It is also possible to use alkaline earth metal hydroxides, alkali metal carbonates, alkali metal hydroxides, etc. These basic catalysts can be used alone or in combination of two or more.When used, these basic catalysts may be used in the form of an aqueous solution of about 10 to 55% by mass, or in the form of a solid.

[0047] The amount of the basic catalyst used is preferably in the range of 0.01 to 1 part by mass, more preferably in the range of 0.05 to 0.8 parts by mass, relative to a total of 100 parts by mass of the phenolic resin (a1), the (meth)acrylate compound having an epoxy group (a2), and the polybasic acid anhydride (a3), because a curable resin composition that has excellent alkali developability and is capable of forming a cured product that is excellent in elongation, adhesion, and dielectric properties can be obtained.

[0048] Examples of the organic solvent include hydrocarbon solvents such as toluene, xylene, heptane, hexane, and mineral spirits; ketone solvents such as methyl ethyl ketone, acetone, dimethylformamide, methyl isobutyl ketone, cyclohexanone, and dimethylacetamide; cyclic ether solvents such as tetrahydrofuran and dioxolane; ester solvents such as methyl acetate, ethyl acetate, and butyl acetate; aromatic solvents such as toluene, xylene, and solvent naphtha; alicyclic solvents such as cyclohexane and methylcyclohexane; carbitol, cellosolve, methanol, ethanol, propanol, isopropanol, butanol, and cyclohexanol. Examples of suitable organic solvents include alcohol solvents such as propylene glycol monomethyl ether and propylene glycol monomethyl ether; ether solvents such as propyl ether, methyl cellosolve, cellosolve, butyl cellosolve, methyl carbitol, and the like; glycol ether solvents such as alkylene glycol monoalkyl ether, dialkylene glycol monoalkyl ether, dialkylene glycol monoalkyl ether acetate, and the like; vegetable oils and fats such as soybean oil, linseed oil, rapeseed oil, safflower oil, and the like; methoxypropanol, cyclohexanone, methyl cellosolve, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and the like. These organic solvents can be used alone or in combination of two or more.

[0049] In addition, commercially available products can also be used as the organic solvent. Examples of commercially available products include "No. 1 Spindle Oil," "No. 3 Solvent," "No. 4 Solvent," "No. 5 Solvent," "No. 6 Solvent," "Naphtesol H," "Alkene 56NT," "AF Solvent No. 4," "AF Solvent No. 5," "AF Solvent No. 6," and "AF Solvent No. 7" manufactured by ENEOS Corporation; "Diadol 13" and "Dialene 168" manufactured by Mitsubishi Chemical Corporation; "F Oxocol" and "F Oxocol 180" manufactured by Nissan Chemical Industries, Ltd.; "Supersol LA35" and "Supersol LA38" manufactured by Idemitsu Kosan Co., Ltd.; and ExxonMobil. Examples of suitable organic solvents include Exxor D80, Exxor D110, Exxor D120, Exxor D130, Exxor D160, Exxor D100K, Exxor D120K, Exxor D130K, Exxor D280, Exxor D300, and Exxor D320 manufactured by Exxor Chemical Co., Ltd. The organic solvents described above can be used alone or in combination of two or more. In the present invention, the amount of organic solvent used is preferably in the range of about 0.1 to 5 times the total mass of the reaction raw materials, as this improves the reaction efficiency.

[0050] The organic solvent may be used in combination with water, and the amount of water in the mixed solvent is preferably 5 to 60 parts by mass, more preferably 10 to 50 parts by mass, per 100 parts by mass of the mixed solvent.

[0051] Examples of the polymerization inhibitor include phenolic compounds such as p-methoxyphenol, p-methoxycresol, 4-methoxy-1-naphthol, 4,4'-dialkoxy-2,2'-bi-1-naphthol, 3-(N-salicyloyl)amino-1,2,4-triazole, N'1,N'12-bis(2-hydroxybenzoyl)dodecane dihydrazide, styrenated phenol, N-isopropyl-N'-phenylbenzene-1,4-diamine, and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline; quinone compounds such as hydroquinone, methylhydroquinone, p-benzoquinone, methyl-p-benzoquinone, 2,5-diphenylbenzoquinone, 2-hydroxy-1,4-naphthoquinone, anthraquinone, and diphenoquinone; melamine, p-phenylenediamine, 4-aminodiphenylamine, and N. Amine compounds such as N'-diphenyl-p-phenylenediamine, N-i-propyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, diphenylamine, 4,4'-dicumyl-diphenylamine, 4,4'-dioctyl-diphenylamine, poly(2,2,4-trimethyl-1,2-dihydroquinoline), styrenated diphenylamine, reaction products of styrenated diphenylamine and 2,4,4-trimethylpentene, reaction products of diphenylamine and 2,4,4-trimethylpentene, phenothiazine, distearyl thiodipropionate, 2,2-bis({[3-(dodecylthio)propionyl]oxy}methyl)-1,3-propanediyl bis[3-(dodecylthio)propionate], ditridecan-1-yl=3,Thioether compounds such as 3'-sulfanediyldipropanoate, N-nitrosodiphenylamine, N-nitrosophenylnaphthylamine, p-nitrosophenol, nitrosobenzene, p-nitrosodiphenylamine, α-nitroso-β-naphthol, N,N-dimethyl p-nitrosoaniline, p-nitrosodiphenylamine, p-nitronedimethylamine, p-nitrone-N,N-diethylamine, N-nitrosoethanolamine, N-nitrosodi-n-butylamine, N-nitroso-N-n-butyl-4-butanolamine, N-nitro N-nitroso-diisopropanolamine, N-nitroso-N-ethyl-4-butanolamine, 5-nitroso-8-hydroxyquinoline, N-nitrosomorpholine, N-nitroso-N-phenylhydroxylamine ammonium salt, nitrosobenzene, N-nitroso-N-methyl-p-toluenesulfonamide, N-nitroso-N-ethylurethane, N-nitroso-N-propylurethane, 1-nitroso-2-naphthol, 2-nitroso-1-naphthol, sodium 1-nitroso-2-naphthol-3,6-sulfonate, 2-nitroso-1-naphthol 4-sodium sulfonate, 2-nitroso-5-methylaminophenol hydrochloride, nitroso compounds such as 2-nitroso-5-methylaminophenol hydrochloride, esters of phosphoric acid and octadecan-1-ol, triphenyl phosphite, 3,9-dioctadecan-1-yl-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, trisnonylphenyl phosphite, phosphorous acid-(1-methylethylidene)-di-4,1-phenylenetetra-C12-15-alkyl ester, 2-ethylhexyl diphenyl phosphite phosphate compounds such as diphenylisodecylphosphite, triisodecylphosphite, and tris(2,4-di-tert-butylphenyl)phosphite; zinc compounds such as bis(dimethyldithiocarbamato-κ(2)S,S')zinc, zinc diethyldithiocarbamate, and zinc dibutyldithiocarbamate; nickel compounds such as bis(N,N-dibutylcarbamodithioato-S,S')nickel; 1,3-dihydro-2H-benzimidazole-2-thione, 4,6-bis(octylthiomethyl)-o-cresol, and 2-methyl-4,Examples of the polymerization inhibitor include sulfur compounds such as 6-bis[(octan-1-ylsulfanyl)methyl]phenol, dilauryl thiodipropionate, and distearyl 3,3'-thiodipropionate. These polymerization inhibitors can be used alone or in combination of two or more.

[0052] As the antioxidant, the same compounds as those exemplified as the polymerization inhibitor can be used, and the antioxidants can be used alone or in combination of two or more kinds.

[0053] In addition, examples of commercially available products of the polymerization inhibitor and the antioxidant include "Q-1300" and "Q-1301" manufactured by Wako Pure Chemical Industries, Ltd., and "Sumilizer BBM-S" and "Sumilizer GA-80" manufactured by Sumitomo Chemical Co., Ltd.

[0054] (Other Carboxyl Group-Containing Resins) In addition to resins containing unit structures represented by the above general formulas (I) to (VI), known and commonly used carboxyl group-containing resins can also be used. The other carboxyl group-containing resins may be used alone or in combination of two or more. Furthermore, the carboxyl group-containing resin can be made photosensitive by having an ethylenically unsaturated double bond in the molecule in addition to the carboxyl group. The ethylenically unsaturated double bond is preferably derived from acrylic acid or methacrylic acid or a derivative thereof.

[0055] Specific examples of the carboxyl group-containing resin include the following compounds (which may be either oligomers or polymers):

[0056] (1) Carboxyl group-containing resins obtained by copolymerizing an unsaturated carboxylic acid such as (meth)acrylic acid with an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth)acrylate, or isobutylene.

[0057] (2) Carboxyl group-containing urethane resins obtained by the polyaddition reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates with carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, and diol compounds such as polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A alkylene oxide adduct diols, and compounds having a phenolic hydroxyl group and an alcoholic hydroxyl group.

[0058] (3) Carboxylic acid group-containing urethane resins obtained by polyaddition reaction of diisocyanates with partially acid anhydride-modified products of reaction products of bifunctional epoxy resins such as bisphenol A epoxy resins, hydrogenated bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bixylenol epoxy resins, and biphenol epoxy resins with monocarboxylic acid compounds having ethylenically unsaturated double bonds such as (meth)acrylic acid, carboxylic acid-containing dialcohol compounds, and diol compounds.

[0059] (4) A curable urethane resin containing a carboxyl group, which is (meth)acrylated at the terminal by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as a hydroxyalkyl (meth)acrylate, during the synthesis of the resin (2) or (3).

[0060] (5) A carboxyl group-containing curable urethane resin that has been (meth)acrylated at its terminal by adding a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate, during the synthesis of the resin (2) or (3).

[0061] (6) A carboxyl group-containing resin obtained by reacting a difunctional or more polyfunctional (solid) epoxy resin with (meth)acrylic acid and adding a dibasic acid anhydride to the hydroxyl groups present in the side chains.

[0062] (7) A carboxyl group-containing resin obtained by reacting a polyfunctional epoxy resin in which the hydroxyl groups of a bifunctional (solid) epoxy resin are further epoxidized with epichlorohydrin with (meth)acrylic acid, and then adding a dibasic acid anhydride to the resulting hydroxyl groups.

[0063] (8) Carboxyl group-containing polyester resins obtained by reacting a dicarboxylic acid such as adipic acid, phthalic acid, or hexahydrophthalic acid with a bifunctional oxetane resin, and then adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the resulting primary hydroxyl groups.

[0064] (9) A carboxyl group-containing resin obtained by reacting an epoxy compound having multiple epoxy groups in one molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenethyl alcohol, and an unsaturated group-containing monocarboxylic acid, such as (meth)acrylic acid, and then reacting the alcoholic hydroxyl groups of the resulting reaction product with a polybasic acid anhydride, such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, or adipic acid.

[0065] (10) A carboxyl group-containing resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide, reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0066] (11) A carboxyl group-containing resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate, reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0067] (12) A carboxyl group-containing resin obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule to any of the resins (1) to (11).

[0068] The phenolic hydroxyl group-containing resin is not particularly limited as long as it has a phenolic hydroxyl group in the main chain or side chain, i.e., a hydroxyl group bonded to a benzene ring. Preferably, the resin has two or more phenolic hydroxyl groups in one molecule. Examples of the resin containing two or more phenolic hydroxyl groups in one molecule include, but are not limited to, catechol, resorcinol, hydroquinone, dihydroxytoluene, naphthalenediol, t-butylcatechol, t-butylhydroquinone, pyrogallol, phloroglucinol, bisphenol A, bisphenol F, bisphenol S, biphenol, bixylenol, novolac-type phenolic resins, novolac-type alkylphenolic resins, bisphenol A novolac resins, dicyclopentadiene-type phenolic resins, Xylok-type phenolic resins, terpene-modified phenolic resins, polyvinylphenols, condensates of phenols with aromatic aldehydes having a phenolic hydroxyl group, and condensates of 1-naphthol or 2-naphthol with aromatic aldehydes.

[0069] The weight-average molecular weight of the carboxyl group-containing resin is preferably 2,000 or more and 15,000 or less. When the weight-average molecular weight of the carboxyl group-containing resin is within the above range, the resin has excellent developability and is particularly effective in reducing residues during development. The weight-average molecular weight can be determined by gel permeation chromatography (GPC) using a standard polystyrene equivalent.

[0070] The content of the carboxyl group-containing resin is preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 45% by mass or less, and even more preferably 20% by mass or more and 40% by mass or less, in terms of solid content, relative to the total amount of the curable resin composition. By making it 10% by mass or more, the strength of the cured product can be improved. Furthermore, by making it 50% by mass or less, the viscosity of the composition can be appropriate, and the application property can be improved.

[0071] (Photopolymerization initiator) The photopolymerization initiator is used to react a photosensitive carboxyl group-containing resin or a photopolymerizable monomer by exposure to light. Any known photopolymerization initiator can be used. One photopolymerization initiator may be used alone, or two or more photopolymerization initiators may be used in combination.

[0072] Specific examples of the photopolymerization initiator include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, and bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide. bisacylphosphine oxides such as sphingonitrile, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, and pivaloylphenylphosphinic acid methyl ester; monoacylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate, 1-hydroxy-cyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-hydroxy Hydroxyacetophenones such as 2-methyl-1-phenylpropan-1-one; benzoins such as benzoin, benzil, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and benzoin n-butyl ether; benzoin alkyl ethers; benzophenones such as benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bisdiethylaminobenzophenone;Acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone acetophenones such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, Anthraquinones such as 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzil dimethyl ketal; benzoic acid esters such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate and p-dimethylbenzoic acid ethyl ester; 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyl oxime esters such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium and titanocenes such as bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyr-1-yl)ethyl)phenyl]titanium; phenyl disulfide 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, tetramethylthiuram disulfide, and the like.

[0073] Commercially available α-aminoacetophenone photopolymerization initiators include Omnirad 907, 369, 369E, and 379 manufactured by IGM Resins. Commercially available acylphosphine oxide photopolymerization initiators include Omnirad 819 manufactured by IGM Resins. Commercially available oxime ester photopolymerization initiators include Irgacure OXE01 and OXE02 manufactured by BASF Japan Ltd., N-1919 manufactured by ADEKA Corporation, ADEKA Arcles NCI-831 and NCI-831E, and TR-PBG-304 manufactured by Changzhou New Advanced Electronic Materials Co., Ltd.

[0074] Other examples include carbazole oxime ester compounds described in JP-A-2004-359639, JP-A-2005-097141, JP-A-2005-220097, JP-A-2006-160634, JP-A-2008-094770, JP-T-2008-509967, JP-T-2009-040762, and JP-A-2011-80036.

[0075] The content of the photopolymerization initiator is preferably 0.1 to 10 mass %, more preferably 0.5 to 7 mass %, calculated as solid content, relative to the total amount of the curable resin composition. When the content of the photopolymerization initiator is 0.1 mass % or more, the photocurability of the curable resin composition is good, and the properties of the cured product, such as chemical resistance, are also good. On the other hand, when the content is 10 mass % or less, light absorption at the surface of the resist film (cured product) is good, and deep curing is less likely to decrease.

[0076] A photoinitiator aid, sensitizer, or catalyst may be used in combination with the above-described photopolymerization initiator. Examples of the photoinitiator aid, sensitizer, or catalyst include benzoin compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, tertiary amine compounds, and xanthone compounds. In particular, it is preferable to use thioxanthone compounds such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, and 4-isopropylthioxanthone. The inclusion of a thioxanthone compound can improve deep curing properties. While these compounds may be used as photopolymerization initiators, it is preferable to use them in combination with a photopolymerization initiator. Furthermore, one type of photoinitiator aid, sensitizer, or catalyst may be used alone, or two or more types may be used in combination.

[0077] These photopolymerization initiators, photoinitiator assistants, sensitizers, and catalysts absorb light of specific wavelengths, which may reduce sensitivity in some cases and function as ultraviolet absorbers. However, they are not used solely for the purpose of improving the sensitivity of the curable resin composition. They can absorb light of specific wavelengths as needed to increase the photoreactivity of the surface, change the line shape and openings of the resist pattern to vertical, tapered, or reverse tapered, and improve the accuracy of the line width and opening diameter.

[0078] (Thermosetting Component) The curable resin composition of the present invention contains a thermosetting component. As the thermosetting component, various conventionally known compounds and resins having thermosetting properties can be used. By including a thermosetting component in the curable resin composition, it is expected that the heat resistance of the composition can be improved. Examples of the thermosetting component used in the present invention include isocyanate compounds, blocked isocyanate compounds, amino resins, maleimide compounds, benzoxazine resins, carbodiimide resins, cyclocarbonate compounds, epoxy resins, oxetane compounds, and episulfide resins. One type of thermosetting component may be used alone, or two or more types may be used in combination. Among these, the preferred thermosetting component is an epoxy resin.

[0079] Examples of epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, hydrogenated bisphenol A epoxy resins, bisphenol S epoxy resins, novolac epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins, biphenyl epoxy resins, naphthalene epoxy resins, dicyclopentadiene epoxy resins, triphenylmethane epoxy resins, glycidylamine epoxy resins, alicyclic epoxy resins, trihydroxyphenylmethane epoxy resins, bixylenol or biphenol epoxy resins, tetraphenylolethane epoxy resins, heterocyclic epoxy resins, diglycidyl phthalate resins, tetraglycidylxylenoylethane resins, glycidyl methacrylate copolymer epoxy resins, cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resins, and CTBN-modified epoxy resins. These may be used alone or in combination of two or more depending on the required properties.

[0080] Commercially available epoxy resins include jER (registered trademark) 828, 806, 807, YX8000, YX8034, 834, and YX4000 manufactured by Mitsubishi Chemical Corporation, YD-128, YDF-170, ZX-1059, and ST-3000 manufactured by Nippon Steel Chemical & Material Co., Ltd., EPICLON (registered trademark) 830, 835, 840, 850, N-730A, N-695, N-860, and N-870 manufactured by DIC Corporation, and RE-306 manufactured by Nippon Kayaku Co., Ltd. These epoxy compounds may be used alone or in combination of two or more.

[0081] The content of the thermosetting component is preferably 5% by mass or more and 30% by mass or less, more preferably 7% by mass or more and 25% by mass or less, and even more preferably 10% by mass or more and 20% by mass or less, in terms of solid content, relative to the total amount of the curable resin composition. When the content of the thermosetting component is within the above numerical range, a cured product having excellent developability and excellent flexibility, adhesion, and heat resistance can be obtained.

[0082] (Inorganic Filler) As the inorganic filler, conventionally known inorganic fillers can be used, including silica, talc, mica, aluminum oxide, calcium oxide, magnesium oxide, zinc oxide, calcium carbonate, magnesium carbonate, fly ash, dewatered sludge, kaolin, clay, calcium hydroxide, aluminum hydroxide, magnesium hydroxide, hydrotalcite, aluminum silicate, magnesium silicate, calcium silicate, wollastonite, potassium titanate, magnesium sulfate, calcium sulfate, magnesium phosphate, sepiolite, zonolite, boron nitride, aluminum borate, silica balloons, glass flakes, glass balloons, steelmaking slag, copper, iron, iron oxide, sendust, alnico magnets, various ferrites and other magnetic powders, cement, glass powder, Neuburg silica, diatomaceous earth, antimony trioxide, magnesium oxysulfate, aluminum hydrate, hydrated gypsum, alum, and barium sulfate. Among these, silica and barium sulfate are preferred. These inorganic fillers may be used alone or in combination of two or more.

[0083] The inorganic filler may be surface-treated to enhance dispersibility in the curable resin composition. Use of a surface-treated inorganic filler can suppress aggregation. The surface treatment method is not particularly limited, and any known or commonly used method may be used. However, it is preferable to treat the surface of the inorganic filler with a surface treatment agent having a curable reactive group, such as a coupling agent having a curable reactive group as an organic group.

[0084] Examples of coupling agents that can be used include silane-based, titanate-based, aluminate-based, and zircoaluminate-based coupling agents. Among these, silane-based coupling agents are preferred. Examples of such silane-based coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N-(2-aminomethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane. These can be used alone or in combination. It is preferred that these silane-based coupling agents are immobilized in advance on the surface of the inorganic filler by adsorption or reaction. Here, the amount of the coupling agent to be treated is preferably 0.5 to 10 parts by mass per 100 parts by mass of the inorganic filler.

[0085] From the viewpoint of dispersibility, the inorganic filler preferably has an average particle size (D50) of 0.12 μm or more and 10 μm or less, more preferably 0.12 μm or more and 5 μm or less, and even more preferably 0.12 μm or more and 1 μm or less. The average particle size refers to the particle size at 50% cumulative volume obtained using a laser diffraction / scattering particle size distribution measurement method. The average particle size of silica refers to the value measured as described above for the inorganic filler before preparing (stirring, kneading) the curable resin composition.

[0086] The content of the inorganic filler is, in terms of solid content, 12% by mass to 80% by mass, preferably 20% by mass to 70% by mass, and more preferably 30% by mass to 60% by mass, based on the total amount of the curable resin composition. When the content of the inorganic filler is within the above range, changes in physical properties of the cured product during high-temperature moisture absorption treatment can be further reduced, and moisture absorption reflow resistance in particular is likely to be improved.

[0087] (Photopolymerizable Monomer) The curable resin composition of the present invention may contain a photopolymerizable monomer. In the present invention, the photopolymerizable monomer is a photopolymerizable monomer having one or more ethylenically unsaturated double bonds in one molecule. By containing the photopolymerizable monomer, the crosslinking density of the curable resin composition during photopolymerization increases, and the heat resistance of the curable resin composition and the chemical resistance of the cured product can be improved. Examples of such photopolymerizable monomers include commonly known polyester (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates, carbonate (meth)acrylates, and epoxy (meth)acrylates.Specific examples include alkyl acrylates such as 2-ethylhexyl acrylate and cyclohexyl acrylate; hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; mono- or diacrylates of alkylene oxide derivatives such as ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol; acrylamides such as N,N-dimethylacrylamide, N-methylolacrylamide, and N,N-dimethylaminopropylacrylamide; aminoalkyl acrylates such as N,N-dimethylaminoethyl acrylate and N,N-dimethylaminopropyl acrylate; polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, and trishydroxyethyl isocyanurate, or alkylene oxides thereof. Polyhydric acrylates derived from alkylene oxide adducts or ε-caprolactone adducts; polyhydric acrylates such as phenols such as phenoxy acrylate and bisphenol A diacrylate or their alkylene oxide adducts; acrylates derived from glycidyl ethers such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate; alicyclic di(meth)acrylate compounds such as tricyclodecane dimethanol di(meth)acrylate; and, without limitation, acrylates and melamine acrylates obtained by directly acridating polyols such as polyether polyols, polycarbonate diols, hydroxyl-terminated polybutadienes, and polyester polyols or by urethane acrylate via diisocyanates, as well as methacrylates corresponding to the above acrylates, can be appropriately selected and used. Such photopolymerizable monomers can also be used as reactive diluents. The photopolymerizable monomers can be used alone or in combination of two or more.

[0088] When the photopolymerizable monomer is contained, the content thereof is preferably 10 mass % or less in terms of solid content relative to the total amount of the curable resin composition. When the content of the photopolymerizable monomer is within the above range, the developability and resolution of the curable resin composition are likely to be further improved.

[0089] (Curing Agent) Examples of the curing agent include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; amine compounds such as dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, and 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; and phosphorus compounds such as triphenylphosphine. Commercially available examples include 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, and 2P4MHZ (all trade names of imidazole-based compounds) manufactured by Shikoku Chemicals Corporation, and U-CAT 3513N (trade name of a dimethylamine-based compound), DBU, DBN, and U-CAT SA 102 (all bicyclic amidine compounds and salts thereof) manufactured by San-Apro Co., Ltd. In particular, the curing agent is not limited to these, and any agent that promotes the reaction of an epoxy resin or oxetane compound curing agent, or at least one of an epoxy group and an oxetanyl group with a carboxyl group may be used, and they may be used alone or in combination of two or more.

[0090] Furthermore, S-triazine derivatives such as guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine·isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine·isocyanuric acid adduct can also be used, and these compounds that also function as adhesion-imparting agents are preferably used in combination with a curing agent. One type of curing agent may be used alone, or two or more types may be used in combination.

[0091] The content of the curing agent is preferably 0.1 to 8 mass %, more preferably 0.3 to 5 mass %, calculated as solid content, based on the total amount of the curable resin composition.

[0092] (Colorant) The curable resin composition of the present invention can be blended with a colorant. The colorant is not particularly limited, and known colorants such as red, blue, green, and yellow can be used. Any of pigments, dyes, and coloring matters can be used, but from the viewpoint of reducing the environmental load and having little effect on the human body, a colorant that does not contain halogen is preferred.

[0093] Red colorants include monoazos, disazos, azo lakes, benzimidazolone, perylene, diketopyrrolopyrrole, condensed azos, anthraquinones, and quinacridones, and specific examples thereof include those having the following Color Index (C.I., published by The Society of Dyers and Colorists) numbers:

[0094] Examples of monoazo red colorants include Pigment Red 1, 2, 3, 4, 5, 6, 8, 9, 12, 14, 15, 16, 17, 21, 22, 23, 31, 32, 112, 114, 146, 147, 151, 170, 184, 187, 188, 193, 210, 245, 253, 258, 266, 267, 268, and 269. Examples of disazo red colorants include Pigment Red 37, 38, and 41. Examples of monoazo lake-based red colorants include Pigment Red 48:1, 48:2, 48:3, 48:4, 49:1, 49:2, 50:1, 52:1, 52:2, 53:1, 53:2, 57:1, 58:4, 63:1, 63:2, 64:1, and 68. Examples of benzimidazolone-based red colorants include Pigment Red 171, 175, 176, 185, and 208. Examples of perylene-based red colorants include Solvent Red 135, 179, Pigment Red 123, 149, 166, 178, 179, 190, 194, and 224. Examples of diketopyrrolopyrrole red colorants include Pigment Red 254, 255, 264, 270, and 272. Examples of condensed azo red colorants include Pigment Red 220, 144, 166, 214, 220, 221, and 242. Examples of anthraquinone red colorants include Pigment Red 168, 177, and 216, and Solvent Red 149, 150, 52, and 207. Examples of quinacridone red colorants include Pigment Red 122, 202, 206, 207, and 209.

[0095] Blue colorants include phthalocyanine-based and anthraquinone-based ones, and examples of pigment-based agents include compounds classified as pigments, such as Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, and 60, and examples of dye-based agents include Solvent Blue 35, 63, 68, 70, 83, 87, 94, 97, 122, 136, 67, and 70. In addition to the above, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

[0096] Examples of yellow colorants include monoazo, disazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone. Examples of anthraquinone yellow colorants include Solvent Yellow 163, Pigment Yellow 24, 108, 193, 147, 199, and 202. Examples of isoindolinone yellow colorants include Pigment Yellow 110, 109, 139, 179, and 185. Examples of condensed azo yellow colorants include Pigment Yellow 93, 94, 95, 128, 155, 166, and 180. Examples of benzimidazolone yellow colorants include Pigment Yellow 120, 151, 154, 156, 175, and 181. Examples of monoazo yellow colorants include Pigment Yellow 1, 2, 3, 4, 5, 6, 9, 10, 12, 61, 62, 62:1, 65, 73, 74, 75, 97, 100, 104, 105, 111, 116, 167, 168, 169, 182, and 183. Examples of disazo yellow colorants include Pigment Yellow 12, 13, 14, 16, 17, 55, 63, 81, 83, 87, 126, 127, 152, 170, 172, 174, 176, 188, and 198.

[0097] In addition, colorants such as purple, orange, brown, and black may be added. Specific examples include C.I. Pigment Black 1, 6, 7, 8, 9, 10, 11, 12, 13, 18, 20, 25, 26, 28, 29, 30, 31, and 32, C.I. Pigment Violet 19, 23, 29, 32, 36, 38, and 42, Solvent Violet 13 and 36, C.I. Pigment Orange 1, 5, 13, 14, 16, 17, 24, 34, 36, 38, 40, 43, 46, 49, 51, 61, 63, 64, 71, and 73, C.I. Pigment Brown 23 and 25, and carbon black.

[0098] (Organic Solvent) The curable resin composition of the present invention may contain an organic solvent for the purpose of preparing the composition, adjusting the viscosity when applying it to a substrate or a film, etc. Examples of the organic solvent include solvents that can be used when producing the carboxyl group-containing resin containing the unit structures represented by the general formulas (I) to (VI) above. Specifically, known and commonly used organic solvents can be used, such as ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, and tripropylene glycol monomethyl ether; esters such as ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, diethylene glycol monoethyl ether acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha. These organic solvents may be used alone or in combination of two or more.

[0099] The content of the organic solvent is not particularly limited, and can be appropriately set depending on the target viscosity so as to facilitate preparation of the curable resin composition.

[0100] (Other Additives) The curable resin composition of the present invention may further contain, as necessary, components such as cyanate compounds, elastomers, mercapto compounds, urethanization catalysts, thixotropic agents, adhesion promoters, block copolymers, chain transfer agents, polymerization inhibitors, copper inhibitors, antioxidants, rust inhibitors, thickeners, at least one of silicone-based, fluorine-based, and polymer-based antifoaming agents and leveling agents, imidazole-based, thiazole-based, and triazole-based silane coupling agents, and flame retardants such as phosphinates, phosphate ester derivatives, and phosphorus compounds such as phosphazene compounds. These may be known in the field of electronic materials.

[0101] [Preparation Method] The curable resin composition of the present invention can be prepared by weighing and blending the components, pre-mixing them with a mixer, and then dispersing and kneading the components in a kneader.

[0102] Examples of the kneading machine include a bead mill, a ball mill, a sand mill, a three-roll mill, and a two-roll mill. Among these, a bead mill is preferably used to improve dispersibility. Dispersion conditions such as the type and particle size of the beads of the bead mill can be appropriately set depending on the target viscosity.

[0103] [Uses] The curable resin composition of the present invention is useful for forming a pattern layer as a permanent coating on a printed wiring board, and is also useful for forming a solder resist, a coverlay, an interlayer insulating layer, a rewiring layer, etc. Furthermore, since the curable resin composition of the present invention can form a cured product that has excellent film strength even when it is a thin film, it can also be suitably used for forming a pattern layer on a printed wiring board that requires a thin film, such as a package substrate (a printed wiring board used for a semiconductor package).

[0104] Furthermore, the curable resin composition of the present invention can be used not only for forming a pattern layer but also for applications in which a pattern layer is not formed, such as molding applications (sealing applications).

[0105] [Dry Film] The curable resin composition of the present invention can also be in the form of a dry film comprising a first film and a resin layer formed on the first film, the resin layer being a dried coating of the curable resin composition. The term "first film" as used herein refers to a film that is at least adhered to the resin layer when the dry film is laminated onto a substrate or other base material by heating or other means so that the resin layer side of the dry film is in contact with the resin layer formed on the dry film and integrally formed. The first film may be peeled from the resin layer in a post-lamination step. In particular, in the present invention, peeling from the resin layer in a post-exposure step is preferred. To form a dry film, the curable resin composition of the present invention is diluted with the organic solvent to an appropriate viscosity, and then coated to a uniform thickness on the first film using a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, or the like. The film is then typically dried at a temperature of 50 to 130°C for 1 to 30 minutes to obtain a film. There is no particular restriction on the thickness of the coating film, but it is generally selected appropriately within the range of 1 to 150 μm, preferably 5 to 60 μm, in terms of the thickness after drying.

[0106] The first film can be any known film without particular limitation, and examples of suitable films include polyester films such as polyethylene terephthalate and polyethylene naphthalate, and films made of thermoplastic resins such as polyimide films, polyamideimide films, polypropylene films, and polystyrene films. Among these, polyester films are preferred from the viewpoints of heat resistance, mechanical strength, ease of handling, etc. A laminate of these films can also be used as the first film.

[0107] From the viewpoint of improving mechanical strength, the above-mentioned thermoplastic resin film is preferably a film stretched in a uniaxial or biaxial direction.

[0108] The thickness of the first film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0109] After forming a resin layer consisting of a dried coating film of the curable resin composition of the present invention on the first film, it is preferable to further laminate a peelable second film on the surface of the resin layer for the purpose of preventing dust from adhering to the surface of the resin layer. The second film in the present invention refers to a film that is peeled from the resin layer before lamination when the dry film is laminated by heating or the like so that the resin layer side of the dry film is in contact with a base material such as a substrate to form an integral mold. Examples of the peelable second film that can be used include polyethylene film, polytetrafluoroethylene film, polypropylene film, surface-treated paper, etc., and any film can be used as long as the adhesive strength between the resin layer and the second film is smaller than the adhesive strength between the resin layer and the first film when the second film is peeled off.

[0110] The thickness of the second film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0111] [Cured Product] The cured product of the present invention is obtained by curing the curable resin composition of the present invention or the resin layer of the dry film of the present invention. The manufacturing conditions such as curing conditions will be described later in [Method for manufacturing printed wiring board]. The cured product of the present invention can be suitably used for printed wiring boards, electronic components, etc.

[0112] [Printed Wiring Board] The printed wiring board of the present invention comprises a circuit board and a cured product obtained from the resin layer of the curable resin composition or dry film of the present invention.

[0113] Examples of the substrate include printed wiring boards and flexible printed wiring boards on which circuits have been formed in advance using copper or the like, as well as copper-clad laminates for high-frequency circuits made of materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, fluororesin / polyethylene / polyphenylene ether, polyphenylene oxide / cyanate, and the like, and include copper-clad laminates of all grades (FR-4, etc.), as well as metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer plates, etc.

[0114] [Method for Manufacturing Printed Wiring Board] In a method for manufacturing a printed wiring board of the present invention, for example, the curable resin composition of the present invention is adjusted to a viscosity suitable for the coating method using the organic solvent, and applied to a substrate by a method such as dip coating, flow coating, roll coating, bar coating, screen printing, or curtain coating. The organic solvent contained in the composition is then evaporated and dried (pre-dried) at a temperature of 60 to 100°C for 15 to 90 minutes to form a tack-free resin layer. There are no particular restrictions on the coating film thickness, but the thickness after drying is generally selected appropriately from the range of 1 to 150 μm, preferably 5 to 60 μm. In the case of a dry film, the resin layer is bonded to the substrate using a laminator or the like so that the resin layer contacts the substrate, forming a resin layer on the substrate.

[0115] The dry film is preferably bonded to the substrate under pressure and heat using a vacuum laminator or the like. By using such a vacuum laminator, when a circuit-formed substrate is used, the dry film adheres tightly to the circuit substrate even if the circuit substrate surface is uneven, preventing the inclusion of air bubbles and improving the filling of recesses in the substrate surface. The pressure condition is preferably about 0.1 to 2.0 MPa, and the heating condition is preferably 40 to 120°C.

[0116] The volatilization drying carried out after the curable resin composition of the present invention is applied to a substrate can be carried out using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, etc. (a method in which hot air in a dryer equipped with a heat source of an air heating method using steam is brought into countercurrent contact with the substrate, or a method in which hot air is blown onto the substrate from a nozzle.) Examples of the apparatus include a hot air circulation drying oven such as DF610 manufactured by Yamato Scientific Co., Ltd.

[0117] After forming a resin layer on a substrate, the resin layer is selectively exposed to active energy rays through a photomask having a predetermined pattern formed thereon, and the unexposed areas are developed with a dilute alkaline aqueous solution (e.g., a 0.3 to 3.0 mass % aqueous sodium carbonate solution) to form a patterned cured product. In the case of a dry film, after exposure, the first film is peeled from the dry film and development is carried out to form a patterned cured product on the substrate. Note that, as long as the properties are not impaired, the first film may be peeled from the dry film before exposure, and the exposed resin layer may be exposed and developed.

[0118] The exposure device used for the active energy ray irradiation may be any device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, or the like, and capable of irradiating ultraviolet rays in the range of 350 to 450 nm. Furthermore, a direct imaging device (for example, a laser direct imaging device that draws an image directly with a laser based on CAD data from a computer) may also be used. The lamp or laser light source of the direct imaging device may have a maximum wavelength in the range of 350 to 450 nm. The exposure dose for image formation varies depending on factors such as the film thickness, but is generally 10 to 1,000 mJ / cm. ２ , preferably 20 to 800 mJ / cm ２ The range may be:

[0119] The developing method may be a dipping method, a shower method, a spray method, a brush method, or the like, and the developing solution may be an aqueous alkali solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, or an amine.

[0120] Furthermore, the cured product is irradiated with active energy rays and then heat-cured (for example, at a temperature of 100 to 220°C for 30 to 90 minutes), or is irradiated with active energy rays (for example, at a temperature of 1,000 to 2,000 mJ / cm ２), or by heat curing only for final finish curing (main curing), a cured product with excellent properties such as adhesion and hardness is formed. Examples of equipment include a UV conveyor using a high-pressure mercury lamp, such as QRM-2082 manufactured by Oak Manufacturing Co., Ltd.

[0121] The present invention will be described in more detail below using examples, but the present invention is not limited to the following examples. In the following, "parts" and "%" are all based on mass in terms of solid content unless otherwise specified.

[0122] [Method for Evaluating the Number of Repeating Units (NMR)] The total number of repeating units of the carboxyl group-containing resins obtained in the following synthesis examples was determined from the results of NMR analysis using an internal standard method. In NMR, the obtained carboxyl group-containing resins were dissolved in deuterated acetone, １ Measurements were carried out using H-NMR (400 MHz). The molar concentration of benzene rings in the carboxyl group-containing resin solution was determined from the measurement results, and the sum of the number of repeating units was calculated by dividing by the molar mass of the benzene rings. [Method for evaluating acid value] The acid value of the carboxyl group-containing resin obtained in the following synthesis examples was calculated in accordance with JIS K0070:1992. [Method for evaluating chlorine content] The chlorine content of the carboxyl group-containing resin obtained in the following synthesis examples was measured by burning and decomposing the carboxyl group-containing resin at high temperature using a combustion tube combustion method, absorbing the decomposition gas into an absorption liquid, and quantifying it by ion chromatography. Ultrapure water containing hydrogen peroxide and hydrazine hydrate was used as the absorption liquid. The ion chromatography used in the combustion tube combustion method was an ion chromatograph "Ion Chromatograph ICS-1500 (detector: electrical conductivity meter)" manufactured by Thermo Fisher Scientific Co., Ltd., and an ion chromatography column "AS-12A manufactured by Thermo Fisher Scientific Co., Ltd.." The eluent was sodium bicarbonate (NaHCO ) with a concentration of 0.3 mM. ３ ) aqueous solution and 2.7 mM sodium carbonate (Na ２ CO ３) aqueous solution, and the flow rate was 1.5 mL / min. [Method for evaluating weight-average molecular weight] The weight-average molecular weight of the carboxyl group-containing resin obtained in the following synthesis examples was measured by gel permeation chromatography (GPC). In GPC, Shodex K-805L was used as the column, the column temperature was 40°C, the flow rate was 1 mL / min, the eluent was chloroform, and the standard substance was polystyrene.

[0123] Synthesis Example 1 Synthesis of Carboxyl Group-Containing Resin 1 A flask equipped with a thermometer, a stirrer, and a reflux condenser was charged with 105.9 parts by mass of diethylene glycol monoethyl ether acetate, and 105 parts by mass of a phenol novolak phenolic resin (PHENOLITE (trade name) TD-2090, manufactured by DIC Corporation, softening point 120°C, phenolic hydroxyl group equivalent 105 g / eq) was dissolved therein. 0.6 parts by mass of dibutylhydroxytoluene and 0.1 parts by mass of methoquinone were added, followed by the addition of 142 parts by mass of glycidyl methacrylate (total chlorine content: 30 ppm) and 1.2 parts by mass of triethylamine. The mixture was reacted at 120°C for 18 hours while blowing in air. Next, 62.3 parts by mass of diethylene glycol monoethyl ether acetate and 65.4 parts by mass of tetrahydrophthalic anhydride were added, and the mixture was reacted at 110°C for 3 hours. Next, 1.2 parts by mass of phosphoric acid was added, and the mixture was stirred at 80°C for 2 hours to obtain a carboxyl group-containing resin. The nonvolatile content of this carboxyl group-containing resin was 65% by mass, the acid value of the solid content was 80 mgKOH / g, and the total chlorine content of the solid content was 11 ppm. The structural units of the carboxyl group-containing resin obtained above were analyzed using NMR, acid value, and chlorine content measurements. The number and ratio of each structural unit in formulas (I) to (VI) were found to be: a + b + c + d + e + f = 36 (a + b) / (a ​​+ b + c + d + e + f) = 0.570 (c + d) / (a ​​+ b + c + d + e + f) = 0.430 (e + f) / (a ​​+ b + c + d + e + f) = 0.0001. The glycidyl methacrylate used in Synthesis Example 1 was purified using preparative HPLC before use. As a result, the chlorine content of the glycidyl methacrylate used was 30 ppm.

[0124] Synthesis Example 2: Synthesis of Another Carboxyl Group-Containing Resin 1 Another carboxyl group-containing resin 1 was synthesized according to the following procedure. First, 220 g of cresol novolac epoxy resin (EPICLON (registered trademark) N-695 manufactured by DIC Corporation, epoxy equivalent: 220) was charged into a four-neck flask equipped with a stirrer and a reflux condenser, and 214 g of carbitol acetate was added and dissolved by heating. Next, 0.1 g of hydroquinone as a polymerization inhibitor and 2.0 g of dimethylbenzylamine as a reaction catalyst were added. The resulting mixture was heated to 95 to 105°C, and 72 g of acrylic acid was gradually added dropwise, allowing the reaction to proceed for 16 hours. The resulting reaction product was cooled to 80 to 90°C, and 106 g of tetrahydrophthalic anhydride was added. The reaction was allowed to proceed for 8 hours, and the resin was then cooled and removed. In this manner, a resin with a solids content of 65%, an acid value of the solids content of 80 mg KOH / g, a weight-average molecular weight of approximately 3,500, and a carboxylic acid equivalent of 701 g / eq. was obtained. A carboxyl group-containing resin of formula (I) was obtained. The obtained carboxyl group-containing resin was designated as other carboxyl group-containing resin 1. The structural units of the carboxyl group-containing resin obtained above were analyzed using the results of measurement of NMR, acid value, and chlorine content. The numbers and ratios of the structural units in formulas (I) to (VI) were found to be as follows: a+b+c+d+e+f=12 (a+b) / (a+b+c+d+e+f)=0.565 (c+d) / (a+b+c+d+e+f)=0.429 (e+f) / (a+b+c+d+e+f)=0.0056

[0125] Synthesis Example 3: Synthesis of Another Carboxyl Group-Containing Resin 2 First, 119.4 parts of a novolac cresol resin (Shonol CRG951 manufactured by Resonac Corporation, OH equivalent: 119.4), 1.19 parts of potassium hydroxide, and 119.4 parts of toluene were charged into an autoclave equipped with a thermometer, a nitrogen introducing device / alkylene oxide introducing device, and a stirrer, and the system was purged with nitrogen while stirring, and heated to a temperature of 125 to 132°C and a pressure of 0 to 4.8 kg / cm. Next, 63.8 parts of propylene oxide were gradually added dropwise, and the temperature was increased to 125 to 132°C and a pressure of 0 to 4.8 kg / cm. ２The reaction was carried out at 100°C for 16 hours. The system was then cooled to room temperature, and 1.56 parts of 89% by weight phosphoric acid was added to the resulting reaction solution and mixed to neutralize the potassium hydroxide, yielding a propylene oxide reaction solution of novolac cresol resin with a nonvolatile content of 62.1% and a hydroxyl value of 182.2 g / eq. The resulting novolac cresol resin had an average of 1.08 moles of alkylene oxide added per equivalent of phenolic hydroxyl group. 293.0 parts of the resulting alkylene oxide reaction solution of novolac 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 charged into a reactor equipped with a stirrer, thermometer, and air inlet tube, and the mixture was reacted at 110°C for 12 hours while stirring and blowing air at a rate of 10 ml / min. The water produced by the reaction was distilled as an azeotrope with toluene, and 12.6 parts of water were distilled off. The system was then cooled to room temperature, and the resulting reaction solution was neutralized with 35.35 parts of 15% aqueous sodium hydroxide and washed with water. The toluene was then distilled off using an evaporator while being replaced with 118.1 parts of diethylene glycol monoethyl ether acetate (carbitol acetate), yielding a novolac acrylate resin solution. Next, 332.5 parts of the resulting novolac acrylate resin solution and 1.22 parts of triphenylphosphine were charged into a reactor equipped with a stirrer, thermometer, and air inlet tube. Air was blown in at a rate of 10 ml / min, and while stirring, 60.8 parts of tetrahydrophthalic anhydride was gradually added. The reaction was carried out at a temperature of 95 to 101°C for 6 hours, and then cooled to yield a carboxyl group-containing resin solution having an acid value of 88 mgKOH / g, a weight average molecular weight of 2550, and a solids content of 65.8%.

[0126] [Examples 1 to 7, Comparative Examples 1 to 3] For each curable resin composition, the components were blended according to the formulation shown in Table 1 below and mixed in a stirrer to prepare a curable resin composition.

[0127]

[0128] The blend amounts in Table 1 are in parts by mass (solid content equivalent). Details of each component in Table 1 are as follows: *1: Carboxylic acid-containing resin synthesized in Synthesis Example 1 *2: Carboxylic acid-containing resin synthesized in Synthesis Example 2 *3: Carboxylic acid-containing resin synthesized in Synthesis Example 3 *4: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (acylphosphine oxide photopolymerization initiator) *5: EPICLON N-680 (DIC Corporation) *6: Melamine (Nissan Chemical Industries, Ltd.) *7: Spherical silica (SFP-130MC (D50: 0.6 μm), Denka Company, Limited) *8: Barium sulfate (B-33 (D50: 0.3 μm), Sakai Chemical Industry Co., Ltd.) *9: DPHA (dipentaerythritol hexaacrylate, Nippon Kayaku Co., Ltd.)

[0129] [Measurement of Glass Transition Temperature (DMA)] The curable resin composition described in each Example and Comparative Example was applied to a first film (polyethylene terephthalate film, T-60, manufactured by Toray Industries, Inc., thickness 38 μm) using an applicator so that the film thickness after drying would be 25 μm, and then dried at 80°C for 20 minutes to produce a dry film. The dry film was heat-laminated onto the glossy side of copper foil (F2-WS manufactured by Furukawa Electric Co., Ltd., thickness 18 μm) using a vacuum laminator (CVP-300, manufactured by Nikko Materials Co., Ltd.) at a temperature of 100°C and a pressure of 0.5 MPa for 1 minute. Thereafter, the entire surface was exposed to an optimum exposure amount using an exposure device equipped with a high-pressure mercury lamp (short arc lamp). After peeling off the first film, the dry film was heated and laminated at 30°C with 1 mass% Na ２ CO ３ The aqueous solution is sprayed at a pressure of 2 kg / cm ２ The optimum exposure amount was determined when the number of steps of the step tablet (T4105C, manufactured by Stouffer) remained after development was 8. Then, a metal halide lamp was used to expose the film to 2000 mJ / m ２After irradiating with ultraviolet light of 1000 kJ / s, the coating was heated at 170°C for 1 hour to obtain a cured coating film. The cured coating film was then peeled off from the copper foil to obtain a cured product. A 5 mm x 40 mm test piece was cut from the cured product, and the temperature at which the change in elastic modulus was maximum was evaluated as the glass transition temperature using the following test machine, a viscoelasticity measuring device. The measurement results for each Example and Comparative Example are shown in Table 2. [Measurement conditions] Test machine: G2 RSA (manufactured by TA Instruments Japan Co., Ltd.) Measurement mode: Tension mode Chuck distance: 10 mm Temperature conditions: Under a nitrogen atmosphere, temperature increased from 30°C to 250°C at a rate of 5°C / min

[0130] [Evaluation of Moisture Absorption Reflow Resistance] The curable resin composition described in each Example and Comparative Example was applied to a first film (polyethylene terephthalate film, T-60, manufactured by Toray Industries, Inc., thickness 38 μm) using an applicator so that the film thickness after curing was 15 μm, and then dried at 80 ° C. for 20 minutes to produce a dry film. The surface of a substrate (50 mm × 50 mm × 0.4 mmt) on which a circuit with a 250 μm bump pitch was formed was chemically polished, and the resin layer of the dry film was bonded. Subsequently, using a vacuum laminator (CVP-300, manufactured by Nikko Materials Co., Ltd.), the film was heat-laminated at a temperature of 100 ° C. and a pressure of 0.5 MPa for 1 minute. Next, after exposure at an optimal exposure dose using an exposure device equipped with a high-pressure mercury lamp (short arc lamp), the first film was peeled off to expose the photosensitive resin layer. Thereafter, 1 mass % Na ２ CO ３ Using an aqueous solution, 30°C, spray pressure 2 kg / cm ２ Then, a metal halide lamp was used to develop the image at 2000 mJ / m ２After irradiating the specimen with ultraviolet light, the specimen was heated at 170°C for 1 hour to produce a cured product. Next, a 20 mm square chip was mounted using the C4 method to produce a test specimen. The test specimen was stored for 168 hours in a thermo-hygrostat chamber at a temperature of 85°C and a humidity of 60%, and then repeatedly subjected to a thermal history of 1 minute or more at a peak temperature of 260°C and a temperature of 240°C or higher. The silicon wafer and solder bumps were removed so that the cured product could be observed, and the presence or absence of cracks in the cured product was observed at 500x magnification using a digital microscope (product name VHX-8000) manufactured by Keyence Corporation. The moisture absorption reflow resistance was evaluated according to the following evaluation criteria. The evaluation results for each example and comparative example are shown in Table 2. [Evaluation criteria] ⊚: No cracks after 10 thermal cycles; ◯: No cracks after 5 thermal cycles, and cracks after 10 thermal cycles; ×: Cracks after 5 thermal cycles.

[0131]

[0132] The results in Table 2 show that the cured products of the curable resin compositions of each Example used the carboxyl group-containing resin obtained in Synthesis Example 1, and the inorganic filler content was 12 mass% or more, calculated as solids, relative to the total amount of the curable resin composition. Therefore, all of them had good moisture absorption reflow resistance. Comparing Comparative Example 1 with Example 1, Example 1 had an inorganic filler content of 12 mass% or more, which is considered to have improved moisture absorption reflow resistance compared to Comparative Example 1. Furthermore, comparing Comparative Examples 2 and 3 with Example 1, Example 1 used the carboxyl group-containing resin obtained in Synthesis Example 1, which is considered to have improved glass transition temperature and moisture absorption reflow resistance. This is presumably because the carboxyl group-containing resin of Synthesis Example 1 used in Example 1 had an improved double bond density in the resin, thereby improving the crosslink density of the cured product of the curable resin composition, and therefore the glass transition temperature. Therefore, the curable resin composition of Example 1 is considered to have improved moisture absorption reflow resistance compared to Comparative Examples 2 and 3, which contain similar amounts of inorganic filler. For this reason, the curable resin composition of the present invention can give a cured product having a high glass transition temperature and excellent moisture absorption reflow resistance.

Claims

1. A curable resin composition comprising a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, and an inorganic filler, wherein the carboxyl group-containing resin is represented by the following general formulas (I) to (VI): (In the formula, R １１ , R ２１ , R ３１ , R ４１ , R ５１ and R ６１ each independently represents a hydrogen atom or a methyl group, R １２ , R ２２ , R ３２ and R ４２ each independently represent a hydrogen atom or an alkyl group, and X represents a single bond or a divalent hydrocarbon group derived from the skeletal structure of a polybasic acid anhydride. In the formula, a, b, c, d, e, and f each represent the number of repetitions of formulas (I) to (VI), and a:b, c:d, and e:f each independently represent a ratio of 100:0 to 0:100, with the proviso that: 5≦a+b+c+d+e+f≦60 is satisfied, 0<(a+b) / (a+b+c+d+e+f)<0.8 is satisfied, 0.2<(c+d) / (a+b+c+d+e+f)<1.0 is satisfied, and (e+f) / (a+b+c+d+e+f)<0.001 is satisfied. a content of the inorganic filler in the curable resin composition is 12% by mass or more and 80% by mass or less in terms of solid content, based on the total amount of the curable resin composition.

2. The curable resin composition according to claim 1, wherein the inorganic filler comprises at least one of silica and barium sulfate.

3. The curable resin composition according to claim 1, wherein the content of the carboxyl group-containing resin is 10% by mass or more and 50% by mass or less in terms of solid content relative to the total amount of the curable resin composition.

4. The curable resin composition according to claim 1, wherein the content of the thermosetting component is 5% by mass or more and 30% by mass or less in terms of solid content relative to the total amount of the curable resin composition.

5. A dry film comprising a first film and a resin layer formed on the first film, the resin layer being a dry coating of the curable resin composition according to any one of claims 1 to 4.

6. A cured product obtained by curing the curable resin composition according to any one of claims 1 to 4.

7. A cured product obtained by curing the resin layer of the dry film according to claim 5.

8. A printed wiring board comprising the cured product according to claim 6.

9. A printed wiring board comprising the cured product according to claim 7.

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