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

Abstract

To provide a curable resin composition in which particle growth due to both an organic filler and a photopolymerization initiator is suppressed even when the composition contains the organic filler and a carboxyl group-containing resin, and haloing is also suppressed.SOLUTION: The curable resin composition according to the present invention is a curable resin composition containing a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, and an organic filler, wherein the carboxyl group-containing resin contains two kinds of carboxyl group-containing resins having specific structures at a predetermined mass ratio, and the content of the organic filler is 0.5% by mass or more in terms of solid content with respect to the total amount of the curable resin composition.SELECTED DRAWING: None

Description

[Technical Field]

[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. [Background technology]

[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 (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 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] When manufacturing printed wiring boards, electroless gold plating is applied to the conductor pads formed in the solder resist openings. Printed wiring boards processed in this way have a problem in that discoloration (haloing phenomenon) is observed around the solder resist openings after the electroless gold plating process. As a means for solving the problem of the haloing phenomenon, a method of adding melamine or a derivative thereof to a curable resin composition that forms a solder resist has been proposed (Patent Document 3). In addition, since solder resists are patterned by alkaline development, they contain phenolic hydroxyl groups or carboxylic acid groups. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 61-243869 [Patent Document 2] International Publication No. 2002 / 024774 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-17444 Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional solder resists (Patent Document 1) contain impurities in the form of organic chlorine in the carboxyl group-containing resin, which hinders insulation reliability. Although a method for synthesizing carboxyl group-containing resins that do not contain organic chlorine is also known (Patent Document 2), curable resin compositions containing these carboxyl group-containing resins may cause ink granulation over time, impairing coatability. In particular, the present inventors have discovered that the following problems arise in both configurations using ordinary carboxyl group-containing resins and carboxyl group-containing resins with reduced impurity content such as chlorine. Carboxyl group-containing resins, which contain carboxylic acid groups or phenolic hydroxyl groups, may cause particle size increase over time due to interaction with melamine or its derivatives. In particular, the resin described in Patent Document 2 has a high acid value, so there is a high risk of particle size increase due to melamine or its derivatives. Furthermore, aromatic compounds having a conjugated system are often used as photopolymerization initiators, and those with high crystallinity may cause particle size increase over time due to interaction with the resin. The resin described in Patent Document 1 has a low acid value, so particle size increase due to melamine or its derivatives is suppressed, but since it has many conjugated systems, particle size increase may occur due to interaction with the photopolymerization initiator.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide a curable resin composition that contains melamine or a derivative thereof and a carboxyl group-containing resin, but that is capable of suppressing particle size increase due to both the melamine or a derivative thereof and the photopolymerization initiator, and also suppressing haloing. Another object 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. [Means for solving the problem]

[0009] As a result of intensive research conducted by the present inventors to achieve the above object, they 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 organic filler, in which the carboxyl group-containing resin contains two types of carboxyl group-containing resins having specific structures (a first carboxyl group-containing resin and a second carboxyl group-containing resin), adjusting the content ratio of the first carboxyl group-containing resin to the second carboxyl group-containing resin to 83:17 to 10:90 on a solids mass basis, and adjusting the content of the organic filler to 0.5 mass% or more on a solids mass basis with respect to the total amount of the curable resin composition.

[0010] That is, according to the present invention, the following inventions are provided. [1] A curable resin composition comprising a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, and an organic filler, the carboxyl group-containing resin includes a first carboxyl group-containing resin and a second carboxyl group-containing resin, The first carboxyl group-containing resin is represented by the following general formulas (I) to (VI): [ka] [ka] [ka] (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 represents a hydrogen atom or an alkyl group, and X represents a single bond or a divalent hydrocarbon group derived from the skeleton 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, however, 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, (e+f) / (a+b+c+d+e+f)<0.001 is satisfied. It includes a unit structure represented by the ratio of the acid group equivalent in terms of solid content of the first carboxyl group-containing resin to the polymerizable unsaturated group equivalent in terms of solid content is 2.0 or more; the second carboxyl group-containing resin has at least one type of acid group and one or more types of polymerizable unsaturated group, the ratio of the acid group equivalent in terms of solid content of the second carboxyl group-containing resin to the polymerizable unsaturated group equivalent in terms of solid content is 1.0 or more and less than 2.0; the ratio of the content of the first carboxyl group-containing resin to the content of the second carboxyl group-containing resin is 83:17 to 10:90 on a solid content mass basis, The content of the organic filler is 0.5 mass% or more in terms of solid content with respect to the total amount of the curable resin composition. Curable resin composition. [2] The curable resin composition according to [1], wherein the acid group equivalent of the second carboxyl group-containing resin is 550 g / eq or more and 750 g / eq or less in terms of solid content. [3] The curable resin composition according to [1] or [2], wherein the second carboxyl group-containing resin has a polymerizable unsaturated group equivalent of 350 g / eq or more and 600 g / eq or less, calculated on a solid content basis. [4] The curable resin composition according to any one of [1] to [3], wherein the content of the carboxyl group-containing resin is 10% by mass or more and 70% by mass or less in terms of solid content, based on the total amount of the curable resin composition. [5] The curable resin composition according to any one of [1] to [4], wherein the organic filler contains nitrogen-containing organic fine particles. [6] The curable resin composition according to any one of [1] to [5], wherein the content of the organic filler is 10 mass % or less in terms of solid content, based on the total amount of the curable resin composition. [7] The curable resin composition according to any one of [1] to [6], wherein the content of the thermosetting component is 5% by mass or more and 40% by mass or less in terms of solid content, based on the total amount of the curable resin composition. [8] A dry film comprising a first film and a resin layer formed on the first film and comprising a dried coating film of the curable resin composition according to any one of [1] to [7]. [9] A cured product obtained by curing the curable resin composition according to any one of [1] to [7].

[10] A cured product obtained by curing the resin layer of the dry film described in [8].

[11] A printed wiring board comprising the cured product according to [9].

[12] A printed wiring board comprising the cured product according to

[10] . [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a curable resin composition that is less likely to cause particle size increase due to both an organic filler and a photopolymerization initiator, and that suppresses haloing. Furthermore, according to the present invention, it is possible 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. DETAILED DESCRIPTION OF THE INVENTION

[0012] [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 organic filler. The carboxyl group-containing resin comprises two types of carboxyl group-containing resins (a first carboxyl group-containing resin and a second carboxyl group-containing resin) having specific structures in a specific mass ratio. By adjusting the content of the organic filler to a specific amount, it is possible to suppress particle size increase due to the melamine or a derivative thereof and the photopolymerization initiator, and also to suppress haloing. Although the reason for this is not entirely clear, it is speculated as follows. That is, in the curable resin composition, particle size increase over time was likely due to the interaction between the carboxyl group-containing resin and melamine or a derivative thereof and / or the photopolymerization initiator, but by including a carboxyl group-containing resin that does not interact easily with melamine or a derivative thereof and the photopolymerization initiator in a predetermined mass ratio, the respective interactions were reduced, and particle size increase of the curable resin composition was suppressed. However, this is merely speculation and is not necessarily limited to this. Furthermore, by including an organic filler in a predetermined content, it is possible to suppress the particle size increase while also suppressing haloing.

[0013] [Definition] Each component constituting the curable resin composition of the present invention will be described below. In this specification, (meth)acrylic acid is a general term for acrylic acid, the corresponding methacrylic acid, and a mixture thereof, (meth)acrylate is a general term for acrylate, the corresponding methacrylate, and a mixture thereof, Similarly, (meth)acryloyl group is a general term for acryloyl group and the corresponding methacryloyl group, and (meth)acryloxy group is a general term for acryloxy group and the corresponding methacryloxy group. In this specification, "reaction raw material" refers to a compound that is used to obtain a target compound through a chemical reaction such as synthesis or decomposition and that partially constitutes the chemical structure of the target compound, excluding substances that act as auxiliary agents in the chemical reaction, such as solvents and catalysts. In this specification, "unit structure" refers to a (repeating) unit of a chemical structure formed during a reaction or polymerization, in other words, a partial structure other than the structure of the chemical bonds involved in the reaction or polymerization in the product compound formed by the reaction or polymerization, which is a so-called residue.

[0014] (Carboxyl group-containing resin) The curable resin composition of the present invention contains a carboxyl group-containing resin, and further contains a first carboxyl group-containing resin and a second carboxyl group-containing resin having specific structures.

[0015] (First carboxyl group-containing resin) The first carboxyl group-containing resin contained in the curable resin composition of the present invention is represented by the following general formulas (I) to (VI): [ka] [ka] [ka] (In the formula, R 11 , R 21 , R 31 , R 41 , R 51 and R 61each independently represents a hydrogen atom or a methyl group, and R 12 , R 22 , R 32 , and R 42 each independently represents a hydrogen atom or an alkyl group, X represents a single bond or a divalent hydrocarbon group derived from the skeleton 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, however, 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, (e+f) / (a+b+c+d+e+f)<0.001 is satisfied. It includes a unit structure represented by:

[0016] The first carboxyl group-containing resin satisfies the condition that the number of repeating unit structures represented by formulas (I) to (VI) is 5≦a+b+c+d+e+f≦60, preferably 5 or more and 55 or less, and even more preferably 5 or more and 50 or less. When the total number of repeating units is less than the upper limit, the developability and resolution are improved, whereas when the total 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 repeating numbers (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.

[0017] The first carboxyl group-containing resin has excellent alkali developability and high photosensitivity, and can give a curable resin composition capable of forming a cured product having excellent heat resistance and substrate adhesion. Therefore, the content of unit structures (I) and (II) that do not contain a carboxyl group or 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. The (a+b) can be calculated by subtracting (c+d) and (e+f) calculated below from the (a+b+c+d+e+f) calculated above.

[0018] The first carboxyl group-containing resin has excellent alkali developability and high photosensitivity, and can give a curable resin composition capable of forming 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, and is preferably 0.25 or more and 0.6 or less. The acid value of the first carboxyl group-containing resin is preferably in the range of 40 to 140 mgKOH / g, and more preferably in the range of 50 to 120 mgKOH / g. In the present invention, the acid value of the first 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).

[0019] The first carboxyl group-containing resin reduces the environmental load and exhibits high insulating reliability when cured. Therefore, it is more preferable that the content of the unit structures (V) and (VI) containing chlorine atoms satisfies (e+f) / (a+b+c+d+e+f)<0.001 and is 0.0005 or less. When the first carboxyl group-containing resin is used in the curable resin composition of the present invention, particularly in a resin material for a solder resist, an insulating material, a resist member, or the like, the cured resin exhibits high insulating reliability and high heat resistance, and can also exhibit excellent resistance to thermal shocks. Generally, in a printed wiring board having conductive wiring or electronic components mounted on or within a substrate made of an insulating material, when a voltage is applied between electrodes on the board, the anode portion of the wiring pattern receives electrons, causing metal ions to be easily dissolved from the surface of the anode portion into moisture or ionic substances contained on the surface of the board or within the substrate. Once the metal ions are dissolved into the moisture or ionic substances, they migrate to the cathode side due to Coulomb force caused by an 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 substrate are present in the moisture or ionic substances, metal ions are more likely to be dissolved, facilitating migration and resulting in reduced insulation reliability. However, the first carboxyl group-containing resin is thought to be able to suppress or prevent such a decrease in insulation reliability because the chlorine atom content in the carboxyl group-containing resin is reduced, and further, the reduced halogen content is thought to reduce the environmental impact. As will be described later, 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, and 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 a chlorine atom (35.45 g / mol).

[0020] In this specification, the method for calculating the content of chlorine atoms in the first 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 first carboxyl group-containing resin, the (meth)acrylate compound (B) having an epoxy group, or the curable resin composition was measured by combusting and decomposing the first 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 the content by ion chromatography. Ultrapure water containing hydrogen peroxide and hydrazine hydrate was used as the absorption liquid. Ion chromatography was performed using an ion chromatograph "Ion Chromatograph ICS-1500 (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 a mixture of a 0.3 mM aqueous solution of sodium bicarbonate (NaHCO3) and a 2.7 mM aqueous solution of sodium carbonate (Na2CO3), and the flow rate was 1.5 mL / min.

[0021] In the present invention, examples of means for making the content of unit structures containing chlorine atoms (e+f) / (a+b+c+d+e+f) in the first carboxyl group-containing resin less than 0.001 include: (1) using compounds that do not contain chlorine atoms for the components constituting the first carboxyl group-containing resin and the raw materials, catalysts, solvents, and additives used to synthesize the components; and (2) subjecting the components constituting the first carboxyl group-containing resin and the raw materials, catalysts, solvents, and additives used to synthesize the components to a purification step for removing chlorine atoms. In the present invention, as a means for making the content of unit structures containing chlorine atoms (e+f) / (a+b+c+d+e+f) in the first carboxyl group-containing resin less than 0.001, it is preferable to use at least one of a means for purifying the resin using preparative HPLC under known conditions, and a means for using compounds that do not contain chlorine atoms as components constituting the first carboxyl group-containing resin and raw materials, catalysts, solvents, and additives for synthesizing the components. As a means for using compounds that do not contain chlorine atoms as the components constituting the first carboxyl group-containing resin and the raw materials, catalysts, solvents, and additives for synthesizing the components, it is preferable to use a (meth)acrylate compound (B) having an epoxy group and having a chlorine atom content of 10 ppm by mass or less, preferably below the detection limit, as will be described later. More specifically, the (meth)acrylate compound (B) having an epoxy group and a chlorine atom content of 10 ppm by mass or less, preferably below the detection limit, has a chemical structure similar to that of a compound synthesized by glycidylating a (meth)acrylate compound (b1) (e.g., an alkali metal salt of (meth)acrylic acid, (meth)acrylic acid) with epichlorohydrin. The (meth)acrylate compound (B) having an epoxy group also 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 or the like. From an industrial viewpoint, the former reaction exhibits a higher yield, but because epichlorohydrin contains chlorine atoms in its molecule, the resulting (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 (for example, glycidol) with (meth)acrylic acid as reaction raw materials. This allows the content of unit structures containing chlorine atoms in the first carboxyl group-containing resin (e+f) / (a+b+c+d+e+f) to be less than 0.001.

[0022] [Method for producing first carboxyl group-containing resin] The first carboxyl group-containing resin used in the present invention can be produced using a phenolic resin (A), a (meth)acrylate compound having an epoxy group (B), and a polybasic acid anhydride (C) as reaction raw materials (1). The phenolic resin (A), the (meth)acrylate compound having an epoxy group (B), and the polybasic acid anhydride (C) will be described below.

[0023] (Phenol-based resin (A)) The phenolic resin (A) in the present invention may 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 phenylenedimethylol, dimethoxymethyl, or halomethyl; reaction products of phenol or cresol with bischloromethylbiphenyl, bismethoxymethyl, phenol aralkyl resins which are reaction products 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 phenol resins; and alkoxy group-containing aromatic ring-modified novolak 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 a first carboxyl group-containing resin that exhibits high insulation reliability, high heat resistance, and excellent resistance to cold and thermal shock. 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.

[0024] <Novolac-type phenolic resin> In the present invention, the novolac type phenolic resin is not particularly limited, and one type may be used, 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, more preferably 1,000 to 7,000.

[0025] 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 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, pt-butylphenol), octylphenol, p-nonylphenol, and p-cumylphenol; polyhydric phenols such as resorcinol, catechol, hydroquinone, and trihydroxybenzene; 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.

[0026] In producing the novolak 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).

[0027] 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. In addition, when producing the novolac phenolic resin, additives such as furfural, urea, melamine, acetoguanamine, and benzoguanamine can 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, still more preferably 0.1 ppm or less, and particularly preferably 0.005 ppm or less.

[0028] 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.

[0029] <Resol-type phenolic 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 raw materials (3) in the same manner as the novolac-type phenolic resin. If necessary, the raw materials (3) may contain one or more selected from the group consisting of an alkaline catalyst, an organic solvent, and an additive. Thus, a resol-type phenolic resin can be obtained by reacting the aldehyde compound (a1) with the phenol compound (a2) in a molar ratio of 1.0 to 4.0 in the presence of a catalyst. 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 in the range of 1.5 to 3.0, because this reduces the amount of unreacted materials 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 producing high-ortho and benzylic types. More specifically, 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 due to their excellent catalytic activity. The alkaline catalyst may be added to the reaction raw material (3) etc. before the reaction or may be added to the reaction raw material (3) etc. 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).

[0030] <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. 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.

[0031] ((Meth)acrylate Compound (B) Having an Epoxy Group) The first carboxyl group-containing resin used in the present invention is glycidyl (meth)acrylate or a glycidyl (meth)acrylate in which the α carbon in the acrylic group is an alkyl group R 2 The structure substituted with (H2C=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 they have a (meth)acryloyl group and an epoxy group in their molecular structure, the specific structure is not particularly limited, and a wide variety of compounds can be used. For example, (meth)acrylate monomers having a glycidyl group, such as 4-hydroxybutyl (meth)acrylate glycidyl ether and epoxycyclohexylmethyl (meth)acrylate; mono(meth)acrylates of diglycidyl ether compounds, such as dihydroxybenzene diglycidyl ether, dihydroxynaphthalene diglycidyl ether, biphenol diglycidyl ether, and bisphenol diglycidyl ether, may be mentioned. 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 kinds.

[0032] 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 still more preferably 1 ppm by mass or more and 100 ppm by mass or less. In the present invention, the content of chlorine atoms in the (meth)acrylate compound (B) having an epoxy group, which is a component in the reaction raw material (1) of the first carboxyl group-containing resin, is 100 ppm by mass or less, so that the content of chlorine atoms in the resin can be 100 ppm by mass or less. A common method for synthesizing glycidyl (meth)acrylate is to use epichlorohydrin as a raw material. These methods can be broadly classified into the following two methods. The first method involves reacting epichlorohydrin with an alkali metal salt of (meth)acrylate in the presence of a catalyst to synthesize glycidyl (meth)acrylate. The second method involves reacting epichlorohydrin with (meth)acrylic acid in the presence of a catalyst, followed by a ring-closing reaction in an aqueous alkaline solution to synthesize glycidyl (meth)acrylate. However, in both methods, epichlorohydrin contains a chlorine atom in the molecule. Therefore, when 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, epichlorohydrin contains chlorine atoms in the molecule, and therefore the resulting (meth)acrylate compound (B) having an epoxy group is likely to 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 by mass or less. Similarly, when the first carboxyl group-containing resin is selected as a curing agent for a curable resin composition, the presence of impurity chlorine atoms or chlorine compounds may affect insulation reliability. Therefore, when the (meth)acrylate compound (B) having an epoxy group according to the present invention is synthesized using epichlorohydrin, it is preferable to reduce the content of chlorine atoms contained in the (meth)acrylate compound (B) having an epoxy group to 100 mass ppm or less by the above-mentioned purification method.

[0033] 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. Examples of such compounds 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 above-mentioned various mono(meth)acrylate monomers; lactone-modified mono(meth)acrylate compounds in which a (poly)lactone structure has been introduced into the molecular structure of the above-mentioned various mono(meth)acrylate compounds; 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 containing (poly)oxyethylene groups 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)oxyethylene 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; the molecular structure of the above-mentioned aliphatic tri(meth)acrylate compounds (Poly)oxyalkylene-modified tri(meth)acrylate compounds having a (poly)oxyalkylene chain such as a (poly)oxyethylene chain, a (poly)oxypropylene chain, or a (poly)oxytetramethylene chain introduced into the structure; lactone-modified tri(meth)acrylate compounds having a (poly)lactone structure 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 higher functionality such as acrylate; (poly)oxyalkylene-modified poly(meth)acrylate compounds having tetrafunctional or higher functionality 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 higher functionality 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)oxyalkylene modified compounds in which a (poly)oxyalkylene chain such as a )oxytetramethylene chain has been introduced; 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, 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.

[0034] 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.

[0035] The amount of the (meth)acrylate compound (B) having an epoxy group used is preferably in the range of 0.9 to 1.2 moles, more preferably 0.95 to 1.1 moles, of the epoxy groups in the (meth)acrylate compound (B) having an epoxy group 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.

[0036] In the present invention, another preferred method for reducing the chlorine atoms contained in the (meth)acrylate compound (B) having an epoxy group or the first carboxyl group-containing resin to 100 mass ppm or less is a production method using an ester exchange 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 of the epoxy group- and hydroxyl group-containing compound such as glycidol with a (meth)acrylic acid ester such as the (meth)acrylate compound (b1) (for example, methyl (meth)acrylate, ethyl (meth)acrylate), a known method can be adopted, 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 filtration, washing with water, or the like before purifying the target product. The epoxy group- and hydroxyl group-containing compound is preferably a hydroxyalkene oxide (epoxyalkanol), for example, a hydroxyalkene oxide having 3 to 10 carbon atoms such as 2,3-epoxypropanol (glycidol) or 2,3-epoxybutanol; or a hydroxycycloalkene oxide having 4 to 10 carbon atoms such as 2,3-epoxycyclobutanol or 2,3-epoxycyclopentanol.

[0037] The ratios of the structural units a:b, c:d, and e:f of the first 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. Below, the reaction process of a phenolic resin with epichlorohydrin or a glycidyl (meth)acrylate, and the reaction process of a reaction product of the phenolic resin with a glycidyl (meth)acrylate with a polybasic acid anhydride are shown for each of the α-addition and β-addition. [ka] (In the formula, R 7 are independently a hydrogen atom or a methyl group; l is independently an integer of 0 or greater; and 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 the asymmetric epoxide having the above substituent, β-addition is likely to occur in the presence of a basic catalyst, whereas 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 described below.

[0038] (Polybasic acid anhydride (C)) By including a unit structure derived from the polybasic acid anhydride (C) as a unit structure constituting the first carboxyl group-containing resin in the present invention, the resulting first carboxyl group-containing resin can exhibit excellent insulating reliability, heat resistance, and thermal shock resistance when cured. Examples of the polybasic acid anhydride (C) in the present invention include saturated polybasic acid anhydrides, unsaturated polybasic acid anhydrides, etc. 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.

[0039] Examples of the saturated polybasic acid anhydride include acid anhydrides of 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, and methylbicyclo[2.2.1]heptane-2,3-dicarboxylic acid. Among these, hexahydrophthalic anhydride (hexahydroisobenzofuran-1,3-dione), methylhexahydrophthalic anhydride (3-methyl-8-oxabicyclo[4.3.0]nonane-7,9-dione), and the like are more preferred.

[0040] 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.

[0041] In the first 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. [ka] (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. * represents 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)-OC(=O)-*).

[0042] These polybasic acid anhydrides may be used alone or in combination of two or more. Among these, saturated polybasic acid anhydrides are preferred, and saturated polybasic acid anhydrides having an alicyclic structure are more preferred, because they can provide a first carboxyl group-containing resin that can form a cured product having high photosensitivity, excellent alkali developability, and excellent heat resistance, heat yellowing resistance, and reflectivity.

[0043] 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, per 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.

[0044] (Other compounds) The first carboxyl group-containing resin may contain, as a reaction raw material (1), compounds other than the phenolic resin (A), the (meth)acrylate compound having an epoxy group (B), and the polybasic acid anhydride (C), if necessary. Examples of the other compounds include unsaturated monobasic acid anhydrides. Examples of the unsaturated monobasic acid anhydride include acrylic acid anhydride, methacrylic acid anhydride, etc. These unsaturated monobasic acid anhydrides can be used alone or in combination of two or more kinds.

[0045] 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 material (solid content) of the first 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.

[0046] The method for producing the first carboxyl group-containing resin is not particularly limited, and any method may be used. For example, the first carboxyl group-containing resin may be produced by reacting 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) all at once, or by sequentially reacting the reaction raw materials. Among these, a preferred method is one 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 of 80 to 140°C, and then the polybasic acid anhydride (C) is added and reacted at a temperature of 80 to 140°C, because this method makes it easier to control the reaction.

[0047] 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.

[0048] 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.

[0049] The amount of the basic catalyst used is preferably in the range of 0.01 to 1 part by mass, more preferably 0.05 to 0.8 parts by mass, relative to 100 parts by mass of the total of the phenolic resin (a1), the (meth)acrylate compound (a2) having an epoxy group, and the polybasic acid anhydride (a3), since 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.

[0050] 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 ethanol and propylene glycol monomethyl ether; ether solvents such as propyl ether, methyl cellosolve, cellosolve, butyl cellosolve, and methyl carbitol; glycol ether solvents such as alkylene glycol monoalkyl ether, dialkylene glycol monoalkyl ether, and dialkylene glycol monoalkyl ether acetate; vegetable oils and fats such as soybean oil, linseed oil, rapeseed oil, and safflower oil; methoxypropanol, cyclohexanone, methyl cellosolve, diethylene glycol monoethyl ether acetate, and propylene glycol monomethyl ether acetate. These organic solvents can be used alone or in combination of two or more.

[0051] In addition, commercially available organic solvents can also be used. Examples of commercially available organic solvents 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 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 can be used alone or in combination of two or more. In the present invention, the amount of the organic solvent used is preferably in the range of about 0.1 to 5 times the total mass of the reaction raw materials, in order to improve the reaction efficiency.

[0052] 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.

[0053] Examples of the polymerization inhibitor include 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, 6-ethoxy-2,2,4-trimethyl- Phenol compounds such as 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, N,N'-diphenyl-p-phenylenediamine, Ni-propyl-N'-phenyl-p-phenylenediamine, N-(1,2-dimethyl-2,3-diphenyl-4-phenylenediamine), and methyl-p-benzoquinone.Amine compounds such as 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 with 2,4,4-trimethylpentene, and reaction products of diphenylamine with 2,4,4-trimethylpentene, phenothiazine, distearyl thiodipropionate, 2,2-bis({[3-(dodecyl) thioether compounds such as N-nitrosodiphenylamine, N-nitrosophenylnaphthylamine, p-nitrosophenol, nitrosobenzene, p-nitrosodiphenylamine, α-nitroso-β-naphthol, N,N-dimethyl p-nitrosoaniline, p-nitrosodiphenylamine, p-nitrosodimethylamine, p-nitroso-β-naphthol, N,N-dimethyl p-nitrosoaniline, p-nitrosodiphenylamine, p-nitrosodimethylamine, p-nitroso-β-naphthol, N,N-dimethyl p-nitrosoaniline, p-nitrosodiphenylamine, p-nitroso-β-naphthol, N,N-dimethyl p-nitrosoaniline ... -N,N-diethylamine, N-nitrosoethanolamine, N-nitrosodi-n-butylamine, N-nitroso-Nn-butyl-4-butanolamine, 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-Nn -Propyl urethane, 1-nitroso-2-naphthol, 2-nitroso-1-naphthol, sodium 1-nitroso-2-naphthol-3,6-sulfonate, sodium 2-nitroso-1-naphthol-4-sulfonate, 2-nitroso-5-methylaminophenol hydrochloride, 2-nitroso-5-methylaminophenol hydrochloride and other nitroso compounds, 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, diphenyl isodecyl phosphite, triisodecyl phosphite, phosphite compounds such as tris(2,4-di-tert-butylphenyl) phosphite, bis(dimethyldithiocarbamato-κ(2)S,S')zinc, zinc diethyldithiocarbamate Examples of polymerization inhibitors include zinc compounds such as zinc dibutyl dithiocarbamate, nickel compounds such as bis(N,N-dibutylcarbamodithioato-S,S')nickel, and sulfur compounds such as 1,3-dihydro-2H-benzimidazole-2-thione, 4,6-bis(octylthiomethyl)-o-cresol, 2-methyl-4,6-bis[(octan-1-ylsulfanyl)methyl]phenol, dilauryl thiodipropionate, and distearyl 3,3'-thiodipropionate. These polymerization inhibitors can be used alone or in combination.

[0054] 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.

[0055] 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.

[0056] [Hydrophobicity parameter S of first carboxyl group-containing resin] The first carboxyl group-containing resin has a hydrophobicity parameter S, as defined below, that satisfies 2.0≦S.

number

[0057] The hydrophobic parameter S of the first carboxyl group-containing resin can be determined from the measured values ​​of the acid group equivalent and the polymerizable unsaturated group equivalent, which can be determined from the measured value of the acid value and the measured value of the repeating number of the unit structure containing the polymerizable unsaturated group.

[0058] The hydrophobic parameter S of the first carboxyl group-containing resin satisfies 2.0≦S, and preferably 2.0≦S≦4.0. When the hydrophobic parameter S of the first carboxyl group-containing resin is within the above range, the amount of acid groups relative to polymerizable unsaturated groups is reduced, making it easier to suppress melamine granulation.

[0059] (Second Carboxyl Group-Containing Resin) The curable resin composition of the present invention further contains a different carboxyl group-containing resin (second carboxyl group-containing resin) in addition to the first carboxyl group-containing resin. The second carboxyl group-containing resin has at least one acid group and one or more polymerizable unsaturated groups, and the hydrophobic parameter S defined above satisfies 1.0≦S<2.0, preferably 1.1≦S≦1.9. When the hydrophobic parameter S of the second carboxyl group-containing resin is within the above range, the amount of polymerizable unsaturated groups relative to the acid groups is reduced, making it easier to suppress initiator particle size increase. The hydrophobic parameter S of the second carboxyl group-containing resin can be determined in the same manner as for the first carboxyl group-containing resin.

[0060] The acid group equivalent of the second carboxyl group-containing resin is preferably 550 g / eq or more and 750 g / eq or less, more preferably 580 g / eq or more and 720 g / eq or less, calculated on a solid content basis. The polymerizable unsaturated group equivalent of the second carboxyl group-containing resin is preferably 350 g / eq or more and 600 g / eq or less, more preferably 370 g / eq or more and 550 g / eq or less, calculated on a solid content basis. When the acid group equivalent and polymerizable unsaturated group equivalent of the second carboxyl group-containing resin are within the above ranges, particle size increase due to the organic filler and initiator can be suitably suppressed.

[0061] Specific examples of the second carboxyl group-containing resin include the following compounds (which may be either oligomers or polymers) that have at least one type of acid group and one or more types of polymerizable unsaturated group and further satisfy the above-defined hydrophobic parameter S of 1.0≦S<2.0:

[0062] (1) Carboxyl group-containing resins obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with unsaturated group-containing compounds such as styrene, α-methylstyrene, lower alkyl (meth)acrylates, and isobutylene.

[0063] (2) Carboxylic acid-containing urethane resins obtained by the polyaddition reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates with carboxyl-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 phenolic hydroxyl groups and alcoholic hydroxyl groups.

[0064] (3) Carboxylic acid group-containing urethane resins obtained by polyaddition reaction of diisocyanates with 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, and monocarboxylic acid compounds having ethylenically unsaturated double bonds such as (meth)acrylic acid, partially acid anhydride-modified products thereof, and carboxyl group-containing dialcohol compounds and diol compounds.

[0065] (4) A curable urethane resin containing a carboxyl group, which is terminally (meth)acrylated 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).

[0066] (5) A carboxyl group-containing curable urethane resin that is (meth)acrylated at the end 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).

[0067] (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.

[0068] (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.

[0069] (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.

[0070] (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.

[0071] (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.

[0072] (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.

[0073] (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 the resins (1) to (11) above.

[0074] 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. A resin containing two or more phenolic hydroxyl groups per molecule is preferred. Examples of resins containing two or more phenolic hydroxyl groups per 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 phenolic hydroxyl groups, and condensates of 1-naphthol or 2-naphthol with aromatic aldehydes.

[0075] The second carboxyl group-containing resin may be used singly or in combination of two or more kinds.

[0076] [Content ratio of first carboxyl group-containing resin to second carboxyl group-containing resin] In the present invention, among the above-mentioned carboxyl group-containing resins, the first carboxyl group-containing resin and the second carboxyl group-containing resin are used in combination. By using the first carboxyl group-containing resin and the second carboxyl group-containing resin in a specific mass ratio, it is possible to suppress particle size increase due to both melamine and the photopolymerization initiator, and to maintain good coatability.

[0077] The content of the first carboxyl group-containing resin and the second carboxyl group-containing resin is, on a solid mass basis, 83:17 to 10:90, more preferably 80:20 to 10:90, and even more preferably 70:30 to 10:90. When the contents of the first carboxyl group-containing resin and the second carboxyl group-containing resin are within the above numerical ranges, particle size increase due to both the melamine and the photopolymerization initiator can be suppressed, and good coatability can be maintained.

[0078] (Other carboxyl group-containing resins) The curable resin composition of the present invention may further contain, in addition to the first carboxyl group-containing resin and the second carboxyl group-containing resin, a different carboxyl group-containing resin, as long as the effects of the present invention are not impaired. The other carboxyl group-containing resin may be a known or commonly used resin, and examples thereof include the carboxyl group-containing resins listed above in (1) to (12).

[0079] The content of the carboxyl group-containing resin is preferably 10% by mass or more and 70% by mass or less, and more preferably 15% by mass or more and 65% by mass or less, in terms of solid content, relative to the total amount of the curable resin composition. By making the content 10% by mass or more, the strength of the cured product can be improved, and by making the content 70% by mass or less, the viscosity of the composition can be appropriate, and the application properties can be improved.

[0080] (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.

[0081] 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. Sphingoxide, bisacylphosphine oxides such as bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, 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, pivaloylphenylphosphinic acid 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 dimethyl-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 Examples of suitable oxime esters include bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium and titanocenes such as bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyr-1-yl)ethyl)phenyl]titanium; phenyl disulfide 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, and tetramethylthiuram disulfide.

[0082] 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, ADEKA Arcures NCI-831 and NCI-831E manufactured by ADEKA Corporation, and TR-PBG-304 manufactured by Changzhou New Advanced Electronic Materials Co., Ltd.

[0083] Other examples include carbazole oxime ester compounds described in JP-A Nos. 2004-359639, 2005-097141, 2005-220097, 2006-160634, 2008-094770, JP-T Nos. 2008-509967, 2009-040762, and 2011-80036.

[0084] The content of the photopolymerization initiator is preferably 0.1 to 10 mass %, more preferably 1 to 7 mass %, calculated as solid content, based on the total amount of the curable resin composition. When the content of the photopolymerization initiator is 0.1% by 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% by mass or less, light absorption at the surface of the resist film (cured product) is good, and deep curability is less likely to decrease.

[0085] 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. Thioxanthone compounds, such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, and 4-isopropylthioxanthone, are particularly preferred. The inclusion of a thioxanthone compound can improve deep curing properties. While these compounds may be used as photopolymerization initiators, they are preferably used in combination with a photopolymerization initiator. The photoinitiator aid, sensitizer, or catalyst may be used alone or in combination of two or more.

[0086] 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.

[0087] (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 the 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.

[0088] 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.

[0089] Examples of 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.

[0090] The content of the thermosetting component is preferably 5% by mass or more and 40% by mass or less, more preferably 7% by mass or more and 35% 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 range, a cured product having excellent developability, flexibility, adhesion, and heat resistance can be obtained.

[0091] (organic filler) The curable resin composition of the present invention contains an organic filler, which includes nitrogen-containing organic fine particles, particularly nitrogen-containing organic fine particles having an aromatic ring. By incorporating the nitrogen-containing organic fine particles, it is possible to obtain a cured product that has excellent BHAST resistance for substrates made of low dielectric loss tangent materials and excellent resistance to tin plating. Furthermore, the nitrogen-containing functional groups of the nitrogen-containing organic fine particles promote the reaction of the thermosetting resin, resulting in stronger tin plating resistance and adhesion. The nitrogen-containing organic fine particles generally have a high melting point, making them difficult to dissolve. If the particle size is large, sufficient adhesion to the substrate between narrow-pitch wirings cannot be achieved. Therefore, nitrogen-containing organic fine particles with a smaller particle size are preferred, and the average particle size of the nitrogen-containing organic fine particles is preferably less than 5 μm, more preferably 2 μm or less, and even more preferably 0.5 μm or less. The smaller the average particle size, the better the adhesion to the substrate between narrow-pitch wirings, improving insulation reliability. The problem of tin plating resistance is particularly pronounced when the filler amount is large. However, according to the present invention, even when the filling amount of silica particles is large, for example, 30 mass % or more, it is possible to obtain a curable resin composition that is resistant to deterioration in BHAST resistance to a substrate made of a low dielectric loss tangent material and in tin plating resistance.

[0092] Examples of the nitrogen-containing organic fine particles 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, 4-methyl-N,N-dimethylbenzylamine, and 4-dimethylaminopyridine; 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 Chemical Industry Co., Ltd., and U-CAT 3513N (a trade name of a dimethylamine-based compound), DBU, DBN, and U-CAT SA 102 (all bicyclic amidine compounds and their salts) manufactured by San-Apro Co., Ltd. In addition, 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. Preferably, these compounds that also function as adhesion promoters are used in combination with the curing accelerator. The curing accelerators can be used alone or in combination of two or more. As the nitrogen-containing organic fine particles, at least one of melamine and dicyandiamide (DICY) is preferred.

[0093] In this specification, the average particle size of the nitrogen-containing organic fine particles refers to the average particle size (D50) including not only the particle size of the primary particles but also the particle size of the secondary particles (aggregates), and is the D50 value measured by a laser diffraction method. An example of a measuring device for the laser diffraction method is Microtrac MT3300EXII manufactured by Nikkiso Co., Ltd.

[0094] The average particle size (D50) of the nitrogen-containing organic fine particles is preferably from 0.01 to 2 μm, and more preferably from 0.01 to 1 μm.

[0095] The effects of the present invention can be effectively achieved when the nitrogen-containing organic fine particles have a melting point of 100° C. or higher. The upper limit of the melting point is not particularly limited, but is preferably 700° C. or lower.

[0096] The average particle size of the nitrogen-containing organic fine particles may be adjusted, and it is preferable to pre-disperse the particles using, for example, a bead mill or a jet mill.

[0097] The content of the organic filler is 0.5% by mass or more, and preferably 0.5% by mass or more and 10% by mass or less, in terms of solid content, based on the total amount of the curable resin composition. When the content of the organic filler is within the above range, haloing can be suitably suppressed while suppressing particle size increase due to the interaction with the carboxyl group-containing resin.

[0098] (inorganic filler) The curable resin composition of the present invention may contain an inorganic filler. Conventional 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 is preferred. These inorganic fillers may be used alone or in combination of two or more.

[0099] 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.

[0100] 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 on the surface of the inorganic filler in advance by adsorption or reaction. Here, the amount of the coupling agent to be treated with respect to 100 parts by mass of the inorganic filler is preferably 0.5 to 10 parts by mass.

[0101] From the viewpoint of dispersibility and the like, the inorganic filler preferably has an average particle size (D50) of 150 nm or more and 900 nm or less, more preferably 200 nm or more and 700 nm 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 and kneading) the curable resin composition.

[0102] The content of the inorganic filler, calculated as solid content, relative to the total amount of the curable resin composition, is preferably 3% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 50% by mass or less. When the content of the inorganic filler is within the above range, the resolution, thermal expansion coefficient, and dielectric properties of the cured product are more likely to be improved.

[0103] (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 including the photopolymerizable monomer, the crosslink density of the curable resin composition during photopolymerization can be increased, 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. Specifically, 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 (e.g., phenoxy acrylate, bisphenol A diacrylate) or their alkylene oxide adducts; acrylates derived from glycidyl ethers (e.g., glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, triglycidyl isocyanurate); alicyclic di(meth)acrylate compounds (e.g., tricyclodecane dimethanol di(meth)acrylate); and, without limitation, acrylates and melamine acrylates obtained by directly or via diisocyanate urethane acrylate of polyols (e.g., polyether polyols, polycarbonate diols, hydroxyl-terminated polybutadienes, polyester polyols), and the like, as well as methacrylates corresponding to the 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.

[0104] 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.

[0105] (coloring agent) A colorant can be blended into the curable resin composition of the present invention. The colorant is not particularly limited, and known colorants such as red, blue, green, and yellow can be used, and any of pigments, dyes, and coloring matters can be used. However, 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.

[0106] Red colorants include monoazos, disazos, azolakes, benzimidazolone, perylene, diketopyrrolopyrrole, condensed azos, anthraquinones, and quinacridones, and specific examples thereof include those having the following Color Index (CI; published by The Society of Dyers and Colourists) numbers:

[0107] 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, Solvent Red 149, 150, 52, and 207. Examples of quinacridone red colorants include Pigment Red 122, 202, 206, 207, and 209.

[0108] Blue colorants include phthalocyanine and anthraquinone types, and pigment types include compounds classified as pigments, such as Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, and 60. Dye types 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.

[0109] Yellow colorants include monoazo, disazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone colorants. For example, anthraquinone yellow colorants include Solvent Yellow 163, Pigment Yellow 24, 108, 193, 147, 199, and 202. Isoindolinone yellow colorants include Pigment Yellow 110, 109, 139, 179, and 185. Condensed azo yellow colorants include Pigment Yellow 93, 94, 95, 128, 155, 166, and 180. 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.

[0110] Other colorants such as purple, orange, brown, and black may also be added. Specific examples include Pigment Black 1, 6, 7, 8, 9, 10, 11, 12, 13, 18, 20, 25, 26, 28, 29, 30, 31, and 32, Pigment Violet 19, 23, 29, 32, 36, 38, and 42, Solvent Violet 13 and 36, CI Pigment Orange 1, 5, 13, 14, 16, 17, 24, 34, 36, 38, 40, 43, 46, 49, 51, 61, 63, 64, 71, and 73, Pigment Brown 23 and 25, and carbon black.

[0111] (organic solvent) The curable resin composition of the present invention may contain an organic solvent for the purpose of adjusting the viscosity when preparing the composition or when applying it to a substrate or film, etc. Examples of the organic solvent include solvents that can be used when producing the first carboxyl group-containing resin. 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.

[0112] 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.

[0113] (Other added ingredients) The curable resin composition of the present invention may further contain, as necessary, components such as a curing agent, a cyanate compound, an elastomer, a mercapto compound, a urethanization catalyst, a thixotropic agent, an adhesion promoter, a block copolymer, a chain transfer agent, a polymerization inhibitor, a copper inhibitor, an antioxidant, a rust inhibitor, a thickener, at least one of a silicone-based, fluorine-based, or polymer-based antifoaming agent and a leveling agent, an imidazole-based, thiazole-based, or triazole-based silane coupling agent, a phosphinate, a phosphate ester derivative, or a phosphorus compound such as a phosphazene compound, etc. These may be flame retardants such as those known in the field of electronic materials.

[0114] [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.

[0115] 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, it is preferable to use a bead mill in order 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.

[0116] [Application] 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 thin, it can also be suitably used for forming a pattern layer on a printed wiring board that requires thinning, such as a package substrate (a printed wiring board used for a semiconductor package).

[0117] 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).

[0118] [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 curable resin layer. 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 typically dried at a temperature of 50 to 130°C for 1 to 30 minutes to obtain a film. There are no particular restrictions 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 thickness after drying.

[0119] 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.

[0120] From the viewpoint of improving mechanical strength, the above-mentioned thermoplastic resin film is preferably a film stretched in a uniaxial or biaxial direction.

[0121] The thickness of the first film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0122] 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.

[0123] The thickness of the second film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0124] [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.

[0125] [Printed wiring board] The printed wiring board of the present invention comprises a circuit board and a cured product obtained from the curable resin composition or the resin layer of the dry film of the present invention.

[0126] Examples of the substrates include printed wiring boards and flexible printed wiring boards with circuits already formed using copper or the like, as well as copper-clad laminates for high-frequency circuits made from 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, etc., including copper-clad laminates of all grades (FR-4, etc.), as well as metal substrates, polyimide film, polyethylene terephthalate film, polyethylene naphthalate (PEN) film, glass substrates, ceramic substrates, wafer plates, etc.

[0127] [Printed wiring board manufacturing method] In a method for producing 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 then coated onto 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 attached to the substrate using a laminator or the like so that the resin layer contacts the substrate, forming a resin layer on the substrate.

[0128] The dry film is preferably applied to the substrate under pressure and heat using a vacuum laminator or the like. By using such a vacuum laminator, even if a circuit-formed substrate is used, the dry film adheres tightly to the circuit substrate, preventing the inclusion of air bubbles and improving the filling of recesses in the substrate surface. The pressure is preferably about 0.1 to 2.0 MPa, and the heating temperature is preferably 40 to 120°C.

[0129] 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 type using steam is brought into countercurrent contact with the substrate, or a method in which hot air is blown onto the substrate from a nozzle.) Examples of the apparatus include a hot air circulation drying oven such as DF610 manufactured by Yamato Scientific Co., Ltd.

[0130] After forming a resin layer on a substrate, it is selectively exposed to active energy rays through a photomask with 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 % sodium carbonate aqueous solution) to form a patterned cured product. In the case of a dry film, after exposure, the first film is peeled off 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 off from the dry film before exposure, and the exposed resin layer may be exposed and developed.

[0131] The exposure device used for the above-mentioned active energy ray irradiation may be a device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, or the like, and capable of irradiating ultraviolet rays in the range of 350 to 450 nm. Furthermore, a direct imaging device (for example, a laser direct imaging device that directly draws an image with a laser based on CAD data from a computer) may also be used. The lamp or laser light source of the direct imaging device may have a maximum wavelength in the range of 350 to 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:

[0132] 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.

[0133] 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 after heat-curing (for example, at a temperature of 1,000 to 2,000 mJ / cm 2 By performing final curing (main curing) by heating alone, or by heat curing alone, a cured product with excellent properties such as adhesion and hardness can be formed. Examples of equipment include a UV conveyor using a high-pressure mercury lamp, such as the QRM-2082 manufactured by Oak Manufacturing Co., Ltd. [Example]

[0134] 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.

[0135] [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 measurement by NMR analysis using the internal standard method. In NMR, the obtained carboxyl group-containing resin was dissolved in deuterated acetone, 1 Measurement was carried out by H-NMR (400 MHz). From the measurement results, the molar concentration of benzene rings in the carboxyl group-containing resin solution was determined, and the sum of the number of repeating units was calculated by dividing the molar concentration by the molar mass of the benzene rings. [Acid value evaluation method] The acid values ​​of the carboxyl group-containing resins obtained in the following synthesis examples were calculated in accordance with JIS K0070:1992 standard. [Method for evaluating chlorine content] The chlorine content of the carboxyl group-containing resins obtained in the following synthesis examples was measured by burning and decomposing the carboxyl group-containing resins at high temperatures 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 and hydrazine hydrate. 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 a mixture of a 0.3 mM aqueous solution of sodium bicarbonate (NaHCO3) and a 2.7 mM aqueous solution of sodium carbonate (Na2CO3), 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 the 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.

[0136] (Synthesis Example 1: Synthesis of First Carboxyl Group-Containing Resin 1) A flask equipped with a thermometer, stirrer, and reflux condenser was charged with 105.9 parts by weight of diethylene glycol monoethyl ether acetate, and 105 parts by weight of a phenol novolac 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 weight of dibutylhydroxytoluene and 0.1 parts by weight of methoquinone were added, followed by 142 parts by weight of glycidyl methacrylate (total chlorine content: 30 ppm) and 1.2 parts by weight of triethylamine. The reaction was carried out at 120°C for 18 hours while blowing in air. Next, 62.3 parts by weight of diethylene glycol monoethyl ether acetate and 65.4 parts by weight of tetrahydrophthalic anhydride were added, and the reaction was carried out at 110°C for 3 hours. Next, 1.2 parts by weight 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 resulting carboxyl group-containing resin was designated as first carboxyl group-containing resin 1. The structural units of the carboxyl group-containing resin obtained above were analyzed using NMR, acid value, and chlorine content measurements. As a result, it was found that the number and ratio of each structural unit in the formulas (I) to (VI) were: 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 It was. In addition, the polymerizable unsaturated group equivalent of this carboxyl group-containing resin was 315 g / eq in terms of solid content, and the hydrophobic parameter of this carboxyl group-containing resin was 2.2. The glycidyl methacrylate used in Example 1 was purified using preparative HPLC before use. As a result, the chlorine content of the glycidyl methacrylate used was 30 ppm.

[0137] (Synthesis Example 2: Synthesis of Second Carboxyl Group-Containing Resin 1) A second carboxyl group-containing resin 1 was synthesized according to the following procedure. First, 220 g of cresol novolac epoxy resin (EPICLON® N-695, manufactured by DIC Corporation, epoxy equivalent: 220) was placed in 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 95-105°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 80-90°C, and 106 g of tetrahydrophthalic anhydride was added. The reaction was allowed to proceed for 8 hours, and the mixture was then cooled and removed. In this way, a carboxyl group-containing resin was obtained with a solid content of 65%, a solid acid value of 80 mgKOH / g, a weight average molecular weight of about 3,500, and a carboxylic acid equivalent of 701 g / eq. In addition, the polymerizable unsaturated group equivalent of this carboxyl group-containing resin was 400 g / eq in terms of solid content, and the hydrophobic parameter of this carboxyl group-containing resin was 1.8. The resulting carboxyl group-containing resin was designated as second carboxyl group-containing resin 1. The structural units of the carboxyl group-containing resin obtained above were analyzed using the acid value, chlorine content, and NMR measurement results. As a result, the number and ratio of each structural unit in the formulas (I) to (VI) were found to be: 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 It was.

[0138] (Synthesis Example 3: Synthesis of second carboxyl group-containing resin 2) First, 119.4 parts of 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 adjusted to 125 to 132°C and a pressure of 0 to 4.8 kg / cm. 2 The reaction was carried out at room temperature for 16 hours. The system was then cooled to room temperature, and 1.56 parts of 89% by mass 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. Air was blown in at a rate of 10 ml / min, and the mixture was stirred while reacting at 110°C for 12 hours. 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 solution and washed with water. The toluene was then distilled off using an evaporator while replacing it with 118.1 parts of diethylene glycol monoethyl ether acetate (carbitol acetate), yielding a novolac acrylate resin solution. Next, 332.5 parts of the obtained novolac acrylate resin solution and 1.22 parts of triphenylphosphine were charged into a reactor equipped with a stirrer, a thermometer, and an air inlet tube, and while blowing air in at a rate of 10 ml / min and stirring, 60.8 parts of tetrahydrophthalic anhydride was gradually added and the mixture was reacted at a temperature of 95 to 101°C for 6 hours, and then cooled to obtain a carboxyl group-containing resin solution having an acid value of 88 mgKOH / g, a weight average molecular weight of 2550, and a solid content of 65.8%. In addition, the polymerizable unsaturated group equivalent of this carboxyl group-containing resin was 530 g / eq in terms of solid content, and the hydrophobic parameter of this carboxyl group-containing resin was 1.2.

[0139] (Synthesis Example 4: Synthesis of second carboxyl group-containing resin 3) A flask equipped with a condenser and a stirrer was charged with 456 parts of bisphenol A, 228 parts of water, and 649 parts of 37% formalin. While maintaining the temperature below 40°C, 228 parts of 25% aqueous sodium hydroxide was added. The reaction was continued for 10 hours at 50°C. After the reaction was completed, the mixture was cooled to 40°C and neutralized to pH 4 with 37.5% aqueous phosphoric acid while maintaining the temperature below 40°C. The mixture was then allowed to stand and the aqueous layer was separated. After separation, 300 parts of methyl isobutyl ketone was added and uniformly dissolved. The mixture was then washed three times with 500 parts of distilled water. Water and solvent were removed under reduced pressure at a temperature below 50°C. The resulting polymethylol compound was dissolved in 550 parts of methanol to obtain 1230 parts of a methanol solution of the polymethylol compound. A portion of the resulting methanol solution of the polymethylol compound was dried at room temperature in a vacuum dryer, revealing a solids content of 55.2%. 500 parts of the resulting methanol solution of the polymethylol compound and 440 parts of 2,6-xylenol were charged and dissolved uniformly at 50°C. After the solution was dissolved uniformly, the methanol was removed under reduced pressure at a temperature of 50°C or less. 8 parts of oxalic acid was then added, and the reaction was carried out at 100°C for 10 hours. After the reaction was completed, the distillate was removed under reduced pressure at 180°C and 50 mmHg, yielding 550 parts of novolak resin A. Furthermore, 130 parts of the novolak resin A, 2.6 parts of a 50% aqueous sodium hydroxide solution, and 100 parts of toluene / methyl isobutyl ketone (mass ratio = 2 / 1) were charged into an autoclave equipped with a thermometer, a nitrogen inlet / alkylene oxide inlet, and a stirrer, and the system was purged with nitrogen while stirring. Then, the temperature was raised to 150°C and 8 kg / cm 2 45 parts of ethylene oxide was gradually introduced and the reaction was carried out at a gauge pressure of 0.0 kg / cm. 2 The reaction was continued for about 4 hours until the reaction mixture reached a final concentration, after which it was cooled to room temperature. 3.3 parts of a 36% aqueous solution of hydrochloric acid was added to the reaction solution and mixed to neutralize the sodium hydroxide. The neutralized reaction product was diluted with toluene, washed with water three times, and the solvent was removed using an evaporator to obtain an ethylene oxide adduct of novolak resin A with a hydroxyl value of 175 g / eq. This product had an average of 1 mole of ethylene oxide added per equivalent of phenolic hydroxyl group. 175 parts of the ethylene oxide adduct of novolak resin A, 50 parts of acrylic acid, 3.0 parts of p-toluenesulfonic acid, 0.1 parts of hydroquinone monomethyl ether, and 130 parts of toluene were charged into a reactor equipped with a stirrer, thermometer, and air inlet tube, and the mixture was stirred while blowing in air. The temperature was raised to 115°C, and the reaction was continued for another 4 hours while distilling off the water produced by the reaction as an azeotrope with toluene. The reaction solution was washed with 5% aqueous NaCl, and the toluene was removed by distillation under reduced pressure. Diethylene glycol monoethyl ether acetate was then added to obtain an acrylate resin solution with a solids content of 68%. Next, 312 parts of the obtained acrylate resin solution, 0.1 parts of hydroquinone monomethyl ether, and 0.3 parts of triphenylphosphine were charged into a four-neck flask equipped with a stirrer and a reflux condenser, and this mixture was heated to 110°C. 45 parts of tetrahydrophthalic anhydride was added, and the mixture was reacted for 4 hours. After cooling, a carboxyl group-containing resin solution having a solid content of 70% and an acid value of the solid content of 86 mgKOH / g was obtained. In addition, the polymerizable unsaturated group equivalent of this carboxyl group-containing resin was 485 g / eq in terms of solid content, and the hydrophobic parameter of this carboxyl group-containing resin was 1.3.

[0140] [Examples 1 to 7, Comparative Examples 1 to 6] For each curable resin composition, the components were blended according to the formulation shown in Table 1 below and mixed with a stirrer.

[0141] [Table 1]

[0142] The blending amounts in Table 1 are in parts by mass (solid content equivalent). Details of each component in Table 1 are as follows: *1: The first carboxyl group-containing resin synthesized in Synthesis Example 1 *2: Second carboxyl group-containing resin 1 synthesized in Synthesis Example 2 *3: Second carboxyl group-containing resin 2 synthesized in Synthesis Example 3 *4: Second carboxyl group-containing resin 3 synthesized in Synthesis Example 4 *5: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (acylphosphine oxide photopolymerization initiator) *6: EPICLONN-770 (phenol novolac epoxy resin, manufactured by DIC Corporation) *7: Melamine (manufactured by Nissan Chemical Industries, Ltd.) *8: SFP-130MC (spherical silica (D50: 600 nm), manufactured by Denka Co., Ltd.) *9: DPHA (Dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd.)

[0143] [Evaluation of melamine granulation] An appropriate amount of the compositions obtained by preparation according to the formulations of Examples 1 to 7 and Comparative Examples 1 to 6 was placed in a transparent glass bottle, sealed, and left to stand at 25°C for one month. The five-grain value was evaluated by particle size measurement using a 25 μm grind gauge in accordance with JIS K5101 and JIS K5600. The evaluation results are shown in Table 2. ◎ or ○ was considered to be acceptable. [Evaluation criteria] ◎: Dispersion determined by the 5-particle value is 5 μm or less ○: Dispersion determined by the 5-particle value is more than 5 μm and less than 10 μm ×: Dispersion determined by the 5-particle value is greater than 10 μm

[0144] [Evaluation of initiator granulation] An appropriate amount of the compositions obtained by preparation according to the formulations of Examples 1 to 7 and Comparative Examples 1 to 6 was placed in a transparent glass bottle, sealed, and left to stand at 25°C for one month. The five-grain value was evaluated by particle size measurement using a 25 μm grind gauge in accordance with JIS K5101 and JIS K5600. The evaluation results are shown in Table 2. ◎ or ○ was considered to be acceptable. [Evaluation criteria] ◎: Dispersion determined by the 5-particle value is 5 μm or less ○: Dispersion determined by the 5-particle value is more than 5 μm and less than 10 μm ×: Dispersion determined by the 5-particle value is greater than 10 μm

[0145] [Appearance evaluation of coating film] The compositions prepared according to the formulations of Examples 1 to 7 and Comparative Examples 1 to 6 were applied to a PET film using an applicator so that the film thickness after drying would be 20 μm, and then dried in a hot air circulating drying oven for 20 minutes. Thereafter, the surface of the resulting coating film (30 cm × 30 cm) was observed under an optical microscope at 20x magnification to check the number of surface defects (cracking and pinholes). The evaluation results are shown in Table 2. [Evaluation criteria] 〇: No defects ×: Defective

[0146] [Evaluation of insulation reliability] CZ-8101B (MEC Co., Ltd.) with an etching rate of 1.0 μm / m 2 On a substrate on which a comb-shaped pattern of L / S=20 / 15 μm was formed, which had been processed under the above conditions, compositions prepared according to the formulations of Examples 1 to 7 and Comparative Examples 1 to 6 were applied so that the film thickness on the conductor was about 15 μm, and the entire surface was exposed to light. After that, development was carried out for twice the time until the unexposed parts of the coating film dissolved in the development process and became invisible from the substrate, and then a UV conveyor equipped with a high-pressure mercury lamp was used to apply 1000 mJ / cm 2 The product was irradiated with ultraviolet light and cured in a hot air drying oven at 150°C for 60 minutes. After that, electrodes were connected and a B-HAST resistance test was carried out under conditions of 130°C, RH 85%, and 3 V. The evaluation results are shown in Table 2. [Evaluation criteria] 〇: No malfunctions for 192 hours ×: Failure occurs within 192 hours

[0147] [Haloing Evaluation] After CZ treatment was performed as a pretreatment for the test substrate, the composition prepared according to the formulation of Examples 1 to 7 and Comparative Examples 1 to 6 was applied to the conductor to a thickness of about 20 μm. 2 After exposure at 1000 mJ / cm 2 , the film was developed for 60 seconds. 2 After post-UV treatment and post-curing at 150°C for 60 minutes, a test substrate was prepared. The test substrates fabricated according to this manufacturing process were electroless gold plated (Ni 3.00 μm, Au 0.03 μm), and the discoloration (haloing) of the appearance around the openings after electroless gold plating was observed using an optical microscope. The evaluation results are shown in Table 2. [Evaluation criteria] ○: Halo amount is less than 5 μm ×: Halo amount is 5 μm or more

[0148] [Table 2]

[0149] As can be seen from the results in Table 2, the curable resin compositions of each Example suppressed melamine particle size increase and initiator particle size increase, and suppressed surface defects in the appearance of the coating film. Furthermore, the evaluation results for insulation reliability and haloing were also good. Comparing Comparative Examples 1 to 5 with Examples 1 to 3, it is believed that Examples 1 to 3 had a mass ratio of the first carboxyl group-containing resin to the second carboxyl group-containing resin (first carboxyl group-containing resin:second carboxyl group-containing resin) of 80:20 to 20:80, which reduced the tendency to increase in particle size and improved the appearance of the coating film compared to Comparative Example 1 (100:0), Comparative Example 2 (85:15), and Comparative Examples 3 to 5 (0:100). Furthermore, when comparing Comparative Example 6 with Example 1, the content of the organic filler in Example 1 was 0.5 mass% or more in terms of solid content relative to the total amount of the curable resin composition, and therefore it is believed that haloing was reduced more than in Comparative Example 4 (0.28 mass%).

Claims

1. A curable resin composition comprising a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, and an organic filler, the carboxyl group-containing resin includes a first carboxyl group-containing resin and a second carboxyl group-containing resin, The first carboxyl group-containing resin is represented by the following general formulas (I) to (VI): 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 (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 represents a hydrogen atom or an alkyl group, and X represents a single bond or a divalent hydrocarbon group derived from the skeleton 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; however, 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, (e+f) / (a+b+c+d+e+f)<0.001 is satisfied. It includes a unit structure represented by the ratio of the acid group equivalent in terms of solid content of the first carboxyl group-containing resin to the polymerizable unsaturated group equivalent in terms of solid content is 2.0 or more; the second carboxyl group-containing resin has at least one type of acid group and one or more types of polymerizable unsaturated group, the ratio of the acid group equivalent in terms of solid content of the second carboxyl group-containing resin to the polymerizable unsaturated group equivalent in terms of solid content is 1.0 or more and less than 2.0; the ratio of the content of the first carboxyl group-containing resin to the content of the second carboxyl group-containing resin is 83:17 to 10:90 based on the mass of the solid content, The content of the organic filler is 0.5 mass% or more in terms of solid content with respect to the total amount of the curable resin composition. Curable resin composition.

2. The curable resin composition according to claim 1, wherein the second carboxyl group-containing resin has an acid group equivalent of 550 g / eq or more and 750 g / eq or less in terms of solid content.

3. The curable resin composition according to claim 1, wherein the second carboxyl group-containing resin has a polymerizable unsaturated group equivalent of 350 g / eq or more and 600 g / eq or less in terms of solid content.

4. The curable resin composition according to claim 1, wherein the content of the carboxyl group-containing resin is 10% by mass or more and 70% by mass or less in terms of solid content with respect to the total amount of the curable resin composition.

5. The curable resin composition according to claim 1 , wherein the organic filler comprises nitrogen-containing organic fine particles.

6. The curable resin composition according to claim 1 , wherein the content of the organic filler is 10 mass % or less in terms of solid content with respect to the total amount of the curable resin composition.

7. The curable resin composition according to claim 1 , wherein the content of the thermosetting component is 5% by mass or more and 40% by mass or less in terms of solid content with respect to the total amount of the curable resin composition.

8. A dry film comprising a first film and a resin layer formed on the first film and comprising a dry coating film of the curable resin composition according to any one of claims 1 to 7.

9. A cured product obtained by curing the curable resin composition according to any one of claims 1 to 7.

10. A cured product obtained by curing the resin layer of the dry film according to claim 8.

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

12. A printed wiring board comprising the cured product according to claim 10.

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