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

Abstract

To provide a curable resin composition which leaves little development residue even when a carboxyl group-containing resin having a low content of impurities such as chlorine is used.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 elastomer, wherein the carboxyl group-containing resin contains a specific structure, and the content of the elastomer is 0.1% by mass or more and 50% by mass or less in terms of solid content based on the total amount of the curable resin composition.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). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 61-243869 [Patent Document 2] International Publication No. 2002 / 024774 Summary of the Invention [Problem to be solved by the invention]

[0006] 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 a carboxyl group-containing resin that does not contain organic chlorine is known (Patent Document 2), when the content of impurities such as chlorine is low, the resin used in the solder resist may localize in the composition, causing uneven development. The present inventors have discovered a particular problem: residues remain at the bottom of the small diameter openings required in recent years.

[0007] 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 leaves little development residue in small diameter openings, even when the curable resin is a carboxyl group-containing resin with a reduced chlorine content. 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]

[0008] Means for Solving the Problems The present inventors have conducted extensive research to achieve the above object, and have found that the above problem can be solved by providing a curable resin composition containing a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, and an elastomer, in which the carboxyl group-containing resin has a specific structure and the content of the elastomer is adjusted to 0.1% by mass or more and 50% by mass or less in terms of solid content, relative to the total amount of the curable resin composition.

[0009] 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 elastomer, The 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 content of the elastomer is 0.1% by mass or more and 50% by mass or less 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 elastomer comprises at least one of core-shell type rubber particles and a non-particle elastomer. [3] The curable resin composition according to [2], wherein the constituent material of the core layer of the core-shell rubber particles is at least one selected from the group consisting of silicone-based elastomers, butadiene-based elastomers, styrene-based elastomers, acrylic elastomers, polyolefin-based elastomers, silicone / acrylic composite elastomers, and (meth)acrylate-based polymers. [4] The curable resin composition according to [2] or [3], wherein the non-particle elastomer is at least one selected from the group consisting of polyester-based elastomers, polyurethane-based elastomers, polyesterurethane-based elastomers, polyamide-based elastomers, polyesteramide-based elastomers, acrylic-based elastomers, and olefin-based elastomers. [5] The curable resin composition according to any one of [1] to [4], wherein the content of the carboxyl group-containing resin is 10% by mass or more and 60% by mass or less in terms of solid content, based on the total amount of the curable resin composition. [6] The curable resin composition according to any one of [1] to [5], wherein the content of the thermosetting component is 5% by mass or more and 30% by mass or less in terms of solid content, based on the total amount of the curable resin composition. [7] 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 [6]. [8] A cured product obtained by curing the curable resin composition according to any one of [1] to [6]. [9] A cured product obtained by curing the resin layer of the dry film described in [7].

[10] A printed wiring board comprising the cured product according to [8].

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

[0010] According to the present invention, it is possible to provide a curable resin composition that leaves little development residue even when a carboxyl group-containing resin with a low content of impurities such as chlorine is used. 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

[0011] [Curable resin composition] The curable resin composition of the present invention includes a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, and an elastomer. In the curable resin composition, the carboxyl group-containing resin has a specific structure, and the content of the elastomer is set to a specific amount, thereby reducing development residues in small-diameter openings in the curable resin composition. Although the reason for this is not entirely clear, it is speculated as follows: In other words, in the curable resin composition, aggregation and orientation were likely to occur due to the low impurity content of the carboxyl group-containing resin, but by adding a predetermined amount of elastomer as a stress relaxation component, aggregation and orientation of the curable resin composition are suppressed, thereby suppressing development that leaves behind components with low developability, such as thermosetting components, and further suppressing swelling and peeling of the resin composition, thereby reducing the development residue of the curable resin composition; however, this is merely speculation and is not necessarily limited to this.

[0012] [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.

[0013] (Carboxyl group-containing resin) The 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 61 each 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:

[0014] The carboxyl group-containing resin used in the present invention satisfies the condition that the number of repeating units of the structural units represented by formulas (I) to (VI) 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.

[0015] The 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) which do not contain a carboxyl group or a chlorine atom satisfies 0<(a+b) / (a+b+c+d+e+f)<0.8, and 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.

[0016] The 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 0.60 or less. The acid value of the 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 carboxyl group-containing resin is a value measured by the neutralization titration method of JIS K 0070 (1992), and the (c+d) can be calculated by dividing the acid value by the molar mass of KOH (56,105 mg / mol).

[0017] The carboxyl group-containing resin reduces the environmental load and exhibits high insulating reliability when cured, so it is more preferable that the content of the 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 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 composition exhibits high insulating reliability and high heat resistance, and also exhibits excellent resistance to thermal shock. 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, since the carboxyl group-containing resin has a reduced content of chlorine atoms, it is believed that this deterioration in insulation reliability can be suppressed or prevented.Furthermore, since the amount of halogen is reduced, it is believed that the environmental load can be reduced. 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).

[0018] In this specification, the content of chlorine atoms in the carboxyl group-containing resin, the (meth)acrylate compound (B) having an epoxy group, or the curable resin composition is calculated as follows. The chlorine atom content in the carboxyl group-containing resin, the epoxy group-containing (meth)acrylate compound (B), or the curable resin composition was measured by burning and decomposing the carboxyl group-containing resin or the curable resin composition at high temperature using a combustion tube combustion method, absorbing the decomposition gas into an absorption liquid, and quantifying it by ion chromatography. 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.

[0019] In the present invention, means for making the content of unit structures containing chlorine atoms in the carboxyl group-containing resin (e+f) / (a+b+c+d+e+f) less than 0.001 include (1) using compounds that do not contain chlorine atoms for the components constituting the carboxyl group-containing resin and the raw materials, catalysts, solvents, and additives used to synthesize the components, and (2) subjecting the components constituting the 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, the means for making the content of chlorine atom-containing unit structures (e+f) / (a+b+c+d+e+f) in the carboxyl group-containing resin less than 0.001 preferably involves at least one of purification using preparative HPLC under known conditions and using compounds that do not contain chlorine atoms as components constituting the 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 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 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 carboxyl group-containing resin, (e+f) / (a+b+c+d+e+f), to be less than 0.001.

[0020] [Method of manufacturing carboxyl group-containing resin] The carboxyl group-containing resin used in the present invention can be produced using a phenolic resin (A), a (meth)acrylate compound 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.

[0021] (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 the carboxyl group-containing resin that exhibits high insulation reliability, high heat resistance, and excellent resistance to 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.

[0022] <Novolac-type phenolic resin (A1)> 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.

[0023] The novolac phenolic resin of the present invention is preferably a resin prepared by reacting an aldehyde compound (a1) and a phenolic compound (a2) as raw materials (2). If necessary, the raw materials (2) may contain one or more 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.

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

[0025] Examples of the catalyst include metal salts such as zinc acetate and manganese borate, and metal oxides such as lead oxide and zinc oxide. These catalysts can be used alone or in combination of two or more. 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.

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

[0027] <Resol-type phenolic resin> The resol-type phenolic resin of the present invention is preferably a resin prepared from an aldehyde compound (a1) and a phenol compound (a2) as reaction raw materials (3), similar to the novolac-type phenolic resin (A1). If necessary, the reaction raw material (3) may contain one or more compounds 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).

[0028] <Other phenolic resins> The other phenolic resins of the present invention may be resins prepared by reacting a compound (a5) having a phenolic hydroxyl group with an aldehyde compound (a1) as reaction raw materials. If necessary, the reaction raw materials may contain one or more selected from the group consisting of the catalyst, organic solvent, acid, and additive. 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 novolac-type phenolic resins or resol-type phenolic resins.

[0029] ((Meth)acrylate Compound (B) Having an Epoxy Group) The carboxyl group-containing resin used in the present invention is glycidyl (meth)acrylate or a carboxyl group-containing resin in which the α carbon of the acrylic group of the acrylate 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.

[0030] In the present invention, the content of chlorine atoms contained in the (meth)acrylate compound (B) having an epoxy group is preferably 500 ppm by mass or less, more preferably 1 ppm by mass or more and 100 ppm by mass or less, and still more preferably 1 ppm by mass or more and 100 ppm by mass or less. In the present invention, the chlorine atom content of the (meth)acrylate compound (B) having an epoxy group, which is a component in the reaction raw material (1) of the carboxyl group-containing resin, is 100 ppm by mass or less, so that the chlorine atom content of 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 synthesizing it by glycidylating it, since epichlorohydrin contains chlorine atoms in the molecule, it is thought that the resulting (meth)acrylate compound (B) having an epoxy group will contain chlorine compounds as by-products at a concentration of about 500 ppm to several percent. Therefore, a carboxyl group-containing resin containing the (meth)acrylate compound (B) having an epoxy group as a component of the reaction raw material (1) may also contain chlorine atoms at a concentration of about 500 ppm to several percent by mass or less. Similarly, when the 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.

[0031] As the (meth)acrylate compound (b1), glycidyl (meth)acrylates are used. Other (meth)acrylate compounds may also be used without any particular limitation as long as they have a (meth)acryloyl group. 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.

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

[0033] The amount of the (meth)acrylate compound (B) having an epoxy group used is preferably in the range 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.

[0034] 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 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.

[0035] The ratios of the structural units a:b, c:d, and e:f of the carboxyl group-containing resin used in the present invention are each independently 100:0 to 0:100. In this reaction system, the (meth)acrylate compound (B) having an epoxy group can be added to the phenolic resin in two forms: β-addition, which is formed by cleavage of an unsubstituted β-carbon in the epoxide, and α-addition, which is formed by cleavage of a substituted α-carbon. 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.

[0036] (Polybasic acid anhydride (C)) By including a unit structure derived from the polybasic acid anhydride (C) as a unit structure constituting the carboxyl group-containing resin of the present invention, the carboxyl group-containing resin obtained as described above 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.

[0037] 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.

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

[0039] In the carboxyl group-containing resin used in the present invention, the divalent hydrocarbon group derived from the skeletal structure of the polybasic acid anhydride is preferably selected from the group consisting of the structures shown below. [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)-*).

[0040] 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 give carboxyl group-containing resins capable of forming cured products having high photosensitivity, excellent alkali developability, and excellent heat resistance, heat yellowing resistance, and reflectivity.

[0041] The amount of the polybasic acid anhydride (C) used is preferably in the range of 0.20 to 1.05 mol, more preferably 0.25 to 0.95 mol, even more preferably 0.30 to 0.95 mol, and still more preferably 0.30 to 0.90 mol, 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.

[0042] (Other compounds) The 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), as 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.

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

[0044] The method for producing the carboxyl group-containing resin is not particularly limited, and any method may be used. For example, the carboxyl group-containing resin may be produced by 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.

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

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

[0047] The amount of the basic catalyst used is preferably in the range of 0.01 to 1 part by mass, more preferably 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.

[0048] Examples of the organic solvent include hydrocarbon solvents such as toluene, xylene, heptane, hexane, and mineral spirits; ketone solvents such as methyl ethyl ketone, acetone, dimethylformamide, methyl isobutyl ketone, cyclohexanone, and dimethylacetamide; cyclic ether solvents such as tetrahydrofuran and dioxolane; ester solvents such as methyl acetate, ethyl acetate, and butyl acetate; aromatic solvents such as toluene, xylene, and solvent naphtha; alicyclic solvents such as cyclohexane and methylcyclohexane; carbitol, cellosolve, methanol, ethanol, propanol, isopropanol, butanol, and cyclohexanol. Examples of suitable organic solvents include alcohol solvents such as 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.

[0049] 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.

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

[0051] Examples of the polymerization inhibitor include 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.

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

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

[0054] (Other carboxyl group-containing resins) The carboxyl group-containing resin may be a resin containing a unit structure represented by the above general formulas (I) to (VI), or may be a known or commonly used resin. The other carboxyl group-containing resins may be used singly or in combination of two or more. Furthermore, the carboxyl group-containing resin may have an ethylenically unsaturated double bond in the molecule in addition to the carboxyl group, thereby making the resin photosensitive. The ethylenically unsaturated double bond is preferably derived from acrylic acid, methacrylic acid, or a derivative thereof.

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

[0056] (1) Carboxyl group-containing resins obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with unsaturated group-containing compounds such as styrene, α-methylstyrene, lower alkyl (meth)acrylates, and isobutylene.

[0057] (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.

[0058] (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.

[0059] (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).

[0060] (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).

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

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

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

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

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

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

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

[0068] The phenolic hydroxyl group-containing resin is not particularly limited as long as it has a phenolic hydroxyl group in the main chain or side chain, i.e., a hydroxyl group bonded to a benzene ring. 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.

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

[0070] The content of the carboxyl group-containing resin is preferably 10% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 60% by mass or less, calculated as solid content, relative to the total amount of the curable resin composition. By setting it to 10% by mass or more, the strength of the cured product can be improved. Furthermore, by setting it to 60% by mass or less, the viscosity of the composition can be appropriate, and the coatability can be improved.

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

[0072] Specific examples of the photopolymerization initiator include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, and bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide. 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.

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

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

[0075] The content of the photopolymerization initiator is preferably 0.1 to 10 mass %, more preferably 1 to 7 mass %, calculated as solid content, relative to the total amount of the curable resin composition. When the content of the photopolymerization initiator is 0.1 mass % or more, the photocurability of the curable resin composition is good, and the properties of the cured product, such as chemical resistance, are also good. On the other hand, when the content is 10 mass % or less, light absorption at the surface of the resist film (cured product) is good, and deep curing is less likely to decrease.

[0076] A photoinitiator aid, sensitizer, or catalyst may be used in combination with the above-described photopolymerization initiator. Examples of the photoinitiator aid, sensitizer, or catalyst include benzoin compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, tertiary amine compounds, and xanthone compounds. 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.

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

[0078] (thermosetting component) The curable resin composition of the present invention contains a thermosetting component. As the thermosetting component, various conventionally known compounds and resins having thermosetting properties can be used. By including 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.

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

[0080] 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.

[0081] The content of the thermosetting component is preferably 5% by mass or more and 30% by mass or less, more preferably 6% by mass or more and 26% by mass or less, and even more preferably 6.5% by mass or more and 25% by mass or less, in terms of solid content, relative to the total amount of the curable resin composition. When the content of the thermosetting component is within the above numerical range, a cured product having excellent developability and excellent flexibility, adhesion, and heat resistance can be obtained.

[0082] (Elastomer) The curable resin composition of the present invention contains an elastomer. When the curable resin composition of the present invention contains a component that acts as a stress relaxation agent having impact resistance, such as a flexible polymer, aggregation and orientation of the curable resin composition are suppressed, and development residues in small diameter openings are particularly reduced. For example, it is preferable that the curable resin composition contains at least one selected from rubber particles and non-particle elastomers.

[0083] [Rubber particles] Specific examples of the rubber particles include silicone rubber particles, acrylic rubber particles, cross-linked acrylonitrile butadiene rubber particles, cross-linked styrene butadiene rubber particles, and core-shell rubber particles, from the viewpoint of crack resistance, adhesion, electrical insulation, etc. of the cured film, with core-shell rubber particles being particularly preferred.

[0084] <Core-shell rubber particles> Core-shell rubber particles refer to a rubber material with a multilayer structure consisting of core layers of different compositions and one or more shell layers covering the core layers. As will be described later, core-shell rubber particles have a core layer made of a material with excellent flexibility and a shell layer made of a material with excellent affinity for other components, which allows for a low modulus of elasticity due to the blending of rubber components while also providing good dispersibility.

[0085] The core layer is made of a material with excellent flexibility, such as a silicone elastomer, a butadiene elastomer, a styrene elastomer, an acrylic elastomer, a polyolefin elastomer, or a silicone / acrylic composite elastomer, but preferably a (meth)acrylate polymer.

[0086] Specific examples of the (meth)acrylate polymer constituting the core layer include: Ethyl acrylate and methyl methacrylate polymer, Methyl acrylate and methyl methacrylate polymers, Polymer of 2-ethylhexyl acrylate and methyl methacrylate, Polymers of butyl acrylate, butyl methacrylate and methyl methacrylate, Polymer of 2-ethylhexyl acrylate, methyl acrylate and methyl methacrylate, Butyl methacrylate, methyl acrylate and methyl methacrylate polymers, Polymer of butyl acrylate, ethyl acrylate and methyl methacrylate, -Butyl acrylate and methyl methacrylate polymer, -Butyl methacrylate and 2-ethylhexyl acrylate polymer, Isobutyl acrylate and methyl methacrylate polymer, Polymers of ethyl acrylate, methyl acrylate and methyl methacrylate, Polymer of butyl acrylate, 2-ethylhexyl acrylate and methyl methacrylate, Polymer of butyl methacrylate, ethyl acrylate and methyl methacrylate, -Butyl acrylate and isobutyl methacrylate polymer, Polymer of butyl acrylate, ethyl methacrylate and methyl acrylate, Polymers of butyl acrylate, methyl acrylate and methyl methacrylate, Ethyl acrylate and ethyl methacrylate polymers, Isobutyl acrylate and octadecyl methacrylate polymer, Polymer of butyl acrylate, isobutyl methacrylate and methyl methacrylate, -Butyl acrylate, methyl acrylate and octadecyl methacrylate polymer, Polymers of ethyl acrylate, ethyl methacrylate and methyl acrylate, Polymers of butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate and methyl methacrylate, Polymer of ethyl acrylate, isooctyl acrylate and methyl methacrylate, Butyl acrylate and dodecyl methacrylate polymer, Polymers of butyl acrylate, butyl methacrylate and 2-ethylhexyl acrylate, Polymer of 2-ethylhexyl acrylate, methyl methacrylate and octadecyl methacrylate, Polymer of butyl acrylate, methyl methacrylate and octadecyl methacrylate, Polymer of dodecyl methacrylate, 2-ethylhexyl acrylate and tridecyl methacrylate, Polymer of 2-ethylhexyl acrylate, methyl methacrylate, pentadecyl methacrylate and tetradecyl methacrylate, Polymers of butyl acrylate, butyl methacrylate, tert-butyl methacrylate and methyl methacrylate, Polymers of dodecyl methacrylate, ethyl acrylate, methyl methacrylate and tridecyl methacrylate are included. The core layer is preferably made of at least one of the above (meth)acrylate polymers.

[0087] On the other hand, as a constituent material of the shell layer, a material having excellent affinity for other components is used. For example, when the curable resin composition contains an epoxy resin, it is preferable to use core-shell type rubber particles having a shell layer made of a material having excellent affinity for the epoxy resin.

[0088] The material constituting the core layer is preferably a rubbery polymer with a glass transition temperature of -30°C or lower, while the material constituting the shell layer is preferably a glassy polymer with a glass transition temperature of 70°C or higher. Such core-shell rubber particles can be produced by a multistage seed emulsion polymerization method consisting of at least two consecutive stages. Alternatively, the seed latex prepared in the first stage can be partially coagulated by solvent coagulation or the like, and then graft-polymerized onto the coagulated latex to form the shell.

[0089] In the first stage polymerization, a (meth)acrylate monomer having an alkyl group with 2 to 8 carbon atoms, preferably the (meth)acrylate monomer and a crosslinkable monomer, are polymerized to prepare a rubbery seed polymer having a glass transition temperature of −30° C. or lower.

[0090] The crosslinkable monomer may be one having two or more double bonds with substantially equal reactivity, such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, butylene glycol diacrylate, butylene glycol dimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, hexanediol diacrylate, hexanediol methacrylate, oligoethylene diacrylate, oligoethylene dimethacrylate, aromatic divinyl monomers such as divinylbenzene, triallyl trimellitate, triallyl isocyanurate, etc. These crosslinkable monomers may be used alone or in combination of two or more, and the amount used is generally selected from the range of 0.01 to 5 mass %, preferably 0.1 to 2 mass %, based on the total weight of the monomers.

[0091] Furthermore, other copolymerizable monomers can be used as desired together with the (meth)acrylate monomer and crosslinkable monomer. Examples of such copolymerizable monomers include aromatic vinyl compounds such as styrene, vinyltoluene, and α-methylstyrene, vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, and vinylidene cyanide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxybutyl acrylate, 2-hydroxyethyl fumarate, hydroxybutyl vinyl ether, monobutyl maleate, glycidyl methacrylate, and butoxyethyl methacrylate. These monomers can be used alone or in combination of two or more, and the amount used is usually selected from a range of 50% by mass or less based on the total weight of the monomers.

[0092] Next, the thus obtained (meth)acrylate polymer particles are used as a core, and a second-stage emulsion polymerization is carried out to form a shell by graft copolymerization of a (meth)acrylate monomer having an alkyl group with 1 to 4 carbon atoms and a crosslinkable monomer. In this case, examples of the (meth)acrylate monomer having an alkyl group with 1 to 4 carbon atoms used include ethyl acrylate, n-butyl acrylate, methyl methacrylate, and butyl methacrylate. These may be used alone or in combination of two or more, but among these, methyl methacrylate is particularly preferred.

[0093] The crosslinkable monomer may be one or more selected from those exemplified in the description of the (meth)acrylate polymer forming the core. The amount of the crosslinkable monomer used is selected from the range of usually 0.01 to 10% by mass, preferably 0.1 to 5% by mass, based on the total weight of the monomers. Furthermore, other copolymerizable monomers can be used together with the (meth)acrylate monomer and crosslinkable monomer as desired. As such other copolymerizable monomers, one or more can be selected from those exemplified in the description of the (meth)acrylate polymer forming the core. The amount used is usually selected from the range of 50% by mass or less based on the total weight of the monomers.

[0094] The core-shell rubber particles obtained by such multistage emulsion polymerization are usually directly spray-dried to obtain core-shell rubber particles with excellent dispersibility in resin components such as epoxy resins. These core-shell rubber particles can be obtained by at least two multistage seed emulsion polymerization methods as described above, but in some cases they may be prepared by partially agglomerating the seed latex prepared in the first stage and then graft-polymerizing the resultant particles thereon. Furthermore, after emulsion polymerization, the latex particles may be coagulated and separated by salting out or freezing, and the resulting wet cake may be dehydrated and dried in a fluidized bed or the like to obtain agglomerated particles.

[0095] In the core-shell type rubber particles thus obtained, the content of the constituent material of the core layer is preferably in the range of 20 to 80% by mass, and the content of the constituent material of the shell layer is preferably in the range of 80 to 20% by mass.

[0096] Furthermore, the weight-average particle diameter of the core of the core-shell type powder polymer is preferably in the range of 0.1 to 2.0 μm. The core particles may be polymerized with the shell component following polymerization of the core component, or the core particles may be aggregated by solvent coagulation or salting-out coagulation before polymerization for coating with the shell component. Many known methods for secondary aggregation are available, and any of them can be used. Core particle diameters less than 0.1 μm result in poor dispersibility due to a large surface area per weight, significantly reducing the mechanical strength and storage stability of compositions containing the core-shell type powder polymer. Core particle diameters greater than 2.0 μm tend to result in reduced shear strength and peel strength. The average shell thickness of the core-shell type powder polymer is preferably 50 Å or greater. If the thickness is less than 50 Å, the shell component will not provide sufficient coverage, resulting in reduced storage stability.

[0097] The core-shell rubber particles may have a curable reactive group on their surface, which may be a thermosetting reactive group or a photocurable reactive group, or may have two or more types of curable reactive groups.

[0098] Examples of the thermosetting reactive group include a hydroxyl group, a carboxyl group, an isocyanate group, an imino group, an epoxy group, an oxetanyl group, a mercapto group, a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an ethoxyethyl group, and an oxazoline group. An epoxy group is more preferable. Examples of the photocurable reactive group include an ethylenically unsaturated group such as a vinyl group, a styryl group, a methacrylic group, and an acrylic group.

[0099] The method for introducing the curable reactive groups on the surface of the rubber particles is not particularly limited, and they may be introduced by any known or commonly used method. For example, when forming a shell layer around the core layer, the shell layer can be introduced by polymerizing a material having a curable reactive group different from the functional group for polymerizing with the core layer into the core layer as a constituent material of the shell layer.

[0100] The rubber particles preferably have an average particle size of 1 nm to 2 μm, in order not to interfere with crosslinking, and more preferably 0.05 to 1 μm.

[0101] (Non-particle elastomer) The curable resin composition of the present invention may contain a non-particle elastomer in place of or in combination with the rubber particles. As the non-particle elastomer, known elastomers such as thermoplastic elastomers can be used. Examples of non-particle elastomers that can be used include polyester elastomers, polyurethane elastomers, polyesterurethane elastomers, polyamide elastomers, polyesteramide elastomers, acrylic elastomers, and olefin elastomers. Resins in which some or all of the epoxy groups of epoxy resins having various skeletons have been modified with both-end carboxylic acid-modified butadiene-acrylonitrile rubber can also be used. Furthermore, epoxy-containing polybutadiene elastomers, acrylic-containing polybutadiene elastomers, hydroxyl-containing polybutadiene elastomers, hydroxyl-containing isoprene elastomers, and block copolymers can also be used. For example, trade names include R-45HT, Poly bd HTP-9 (both manufactured by Idemitsu Kosan Co., Ltd.), Epolead PB3600 (manufactured by Daicel Corporation), Denalex R-45EPT (manufactured by Nagase ChemteX Corporation), Tafthren (manufactured by Sumitomo Chemical Co., Ltd.), Ricon 130, Ricon 131, Ricon 134, Ricon 142, Ricon 150, Ricon 152, Ricon 153, Ricon 154, Ricon 156, Ricon 157, Ricon 100, Ricon 181, Ricon 184, Ricon 130MA8, Ricon 130MA13, Ricon 130MA20, Ricon 131MA5, Ricon 131MA10, Ricon Examples of suitable non-particulate elastomers include Ricon 131MA17, Ricon 131MA20, Ricon 184MA6, and Ricon 156MA17 (all manufactured by Cray Valley). These non-particulate elastomers can be used alone or in combination of two or more.

[0102] (polyester polyol) The non-particle elastomer according to the present invention may be, for example, a polyester polyol obtained by polycondensation of a polycarboxylic acid and a polyhydric alcohol. The polyester polyol contained in the resin composition of the present invention may be one type or multiple types.

[0103] (Polycarboxylic Acid) Examples of polybasic carboxylic acids include polybasic acids that provide polybasic acid anhydrides (C) containing the unit structures represented by the general formulae (I) to (VI) and that serve as raw materials for the carboxyl group-containing resins. Specific examples include malonic acid, succinic acid, succinic anhydride, glutaric acid, adipic acid, azelaic acid, sebacic acid, phthalic acid, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, isophthalic acid, terephthalic acid, nadic anhydride, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, and pyromellitic anhydride. Of these, aliphatic polybasic carboxylic acids such as succinic acid, adipic acid, and sebacic acid are preferred.

[0104] (Polyhydric alcohol) Examples of polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,2-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, cyclohexanediol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, glycerin, trimethylolpropane, trimethylolethane, and pentaerythritol, of which 1,2-propylene glycol, 1,4-butylene glycol, and 1,6-hexanediol are preferably used.

[0105] In particular, the polyester polyol used as the elastomer according to the present invention is preferably an aliphatic polyester polyol, which is a polycondensation product of an aliphatic polycarboxylic acid and an aliphatic polyhydric alcohol, since it can provide a fiber-reinforced composite material with high mechanical properties. In particular, an aliphatic polyester polyol using succinic acid, adipic acid, sebacic acid, or the like as the aliphatic polycarboxylic acid and 1,2-propylene glycol, 1,4-butylene glycol, 1,6-hexanediol, or the like as the aliphatic polyhydric alcohol is more preferred, since it can provide a fiber-reinforced composite material with high 90° flexural strength.

[0106] The weight average molecular weight of the polyester polyol is preferably 40,000 or less, more preferably 20,000 or less, and even more preferably 10,000 or less, from the viewpoint of developability. For example, trade names include Polylite OD-X-2068 and OD-X-3100 (both polyester polyols manufactured by DIC Corporation).

[0107] The above elastomers may be used alone or in combination of two or more. The content of the elastomer is, in terms of solid content, 0.1% by mass to 50% by mass, preferably 0.1% by mass to 35% by mass, and more preferably 1% by mass to 20% by mass, based on the total amount of the curable resin composition. When the content of the elastomer is within the above numerical range, aggregation and orientation of the curable resin composition are suppressed, and swelling and peeling of the curable resin composition are suppressed, so it is presumed that development residues are likely to be reduced, but this is merely a matter of presumption and is not necessarily limited to this.

[0108] (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 and barium sulfate are preferred. These inorganic fillers may be used alone or in combination of two or more.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] The content of the inorganic filler, calculated as solid content, relative to the total amount of the curable resin composition, is preferably 3.2% by mass or more and 60% by mass or less, and more preferably 5% by mass or more and 55% 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.

[0113] (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.

[0114] 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.

[0115] (hardening agent) Examples of the curing agent include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; amine compounds such as dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, and 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; and phosphorus compounds such as triphenylphosphine. Commercially available examples include 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, and 2P4MHZ (all trade names of imidazole-based compounds) manufactured by Shikoku Chemical Industry Co., Ltd., and U-CAT 3513N (trade name of a dimethylamine-based compound), DBU, DBN, and U-CAT SA 102 (all bicyclic amidine compounds and salts thereof) manufactured by San-Apro Co., Ltd. However, the curing agent is not limited to these, and any curing agent that promotes the reaction of at least one of an epoxy group and an oxetanyl group with a carboxyl group may be used, and they may be used alone or in combination of two or more.

[0116] Furthermore, S-triazine derivatives such as guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine·isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine·isocyanuric acid adduct can also be used, and these compounds that also function as adhesion promoters are preferably used in combination with a curing agent. The curing agents may be used alone or in combination of two or more.

[0117] The content of the curing agent is preferably 0.1 to 8 mass %, more preferably 0.3 to 5 mass %, calculated as solid content, based on the total amount of the curable resin composition.

[0118] (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.

[0119] 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:

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] (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 above-mentioned carboxyl group-containing resin containing the unit structures represented by the above general formulas (I) to (VI). 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.

[0125] 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.

[0126] (Other added ingredients) The curable resin composition of the present invention may further contain, as necessary, components such as cyanate compounds, mercapto compounds, urethanization catalysts, thixotropic agents, adhesion promoters, block copolymers, chain transfer agents, polymerization inhibitors, copper inhibitors, antioxidants, rust inhibitors, thickeners, at least one of silicone-based, fluorine-based, and polymer-based antifoaming agents and leveling agents, imidazole-based, thiazole-based, and triazole-based silane coupling agents, and flame retardants such as phosphinates, phosphate ester derivatives, and phosphorus compounds such as phosphazene compounds. These may be known in the field of electronic materials.

[0127] [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.

[0128] 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.

[0129] [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).

[0130] 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).

[0131] [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 formed on the dry film and integrally formed. The first film may be peeled from the resin layer in a post-lamination step. In particular, in the present invention, peeling from the resin layer in a post-exposure step is preferred. To form a dry film, the curable resin composition of the present invention is diluted with the organic solvent to an appropriate viscosity, and then coated to a uniform thickness on the first film using a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, or the like. The film is 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.

[0132] 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.

[0133] From the viewpoint of improving mechanical strength, the above-mentioned thermoplastic resin film is preferably a film stretched in a uniaxial or biaxial direction.

[0134] The thickness of the first film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0135] 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.

[0136] The thickness of the second film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0137] [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.

[0138] [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.

[0139] 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.

[0140] [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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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:

[0145] 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.

[0146] Furthermore, the cured product is irradiated with active energy rays and then heat-cured (for example, at a temperature of 100 to 220°C for 30 to 90 minutes), or is irradiated with active energy rays (for example, at a temperature of 1,000 to 2,000 mJ / cm 2 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]

[0147] 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.

[0148] [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.

[0149] (Synthesis Example 1: Synthesis of carboxyl group-containing resin) 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 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. 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.

[0150] [Examples 1 to 9, Comparative Examples 1 and 2] For each curable resin composition, the components were blended according to the formulation shown in Table 1 below and mixed with a stirrer.

[0151] [Table 1]

[0152] 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: Carboxyl group-containing resin synthesized in Synthesis Example 1 *2: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (acylphosphine oxide photopolymerization initiator) *3: EPICLON N-770 (DIC Corporation) *4: Melamine (manufactured by Nissan Chemical Industries, Ltd.) *5: Spherical silica (SFP-130MC (D50: 600 nm), manufactured by Denka Co., Ltd.) *6: Barium sulfate (B-33 (D50: 300 nm), manufactured by Sakai Chemical Industry Co., Ltd.) *7: DPHA (Dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd.) *8: MX-960 (Silicone core (core-shell structure), manufactured by Kaneka Corporation) *9: C-223A (butadiene rubber (core-shell structure), manufactured by Mitsubishi Chemical Corporation) *10: Nipporan 4002 (polyester polyol (non-particle elastomer), manufactured by Tosoh Corporation)

[0153] (Dry film preparation) The curable resin compositions of Examples 1 to 6 and Comparative Examples 1 and 2 obtained as described above were diluted with 300 g of propylene glycol monomethyl ether acetate (PMA) and stirred for 15 minutes with a stirrer to obtain a coating solution. The coating solution was applied to a 38 μm-thick polyethylene terephthalate film (Emblet PTH-25, manufactured by Unitika Ltd.) as a first film and dried at 80°C for 20 minutes to form a 25 μm-thick resin layer. Next, a 18 μm-thick polypropylene film (OPP-FOA, manufactured by Futamura Chemical Co., Ltd.) as a second film was laminated onto the resin layer to produce a dry film.

[0154] (Evaluation of development residue) An FR-4.0 glass cloth-based epoxy resin multilayer substrate (1.6 mm thick, copper-clad laminate with 18 μm copper foil) was electrolytically plated with 17 μm of copper and treated with a MEC CZ-8101B etching process to achieve a thickness equivalent to 1.0 μm. The second film was then peeled from the resin layer of the dry film prepared in the above procedure (preparation of dry film). The resin layer was then laminated onto the substrate using a vacuum laminator (CVP-300, Nikko Materials Co., Ltd.) at 90 °C in the first chamber under conditions of 3 hPa vacuum pressure and 30 seconds of vacuuming. The laminate was then pressed under conditions of 0.5 MPa pressure and 30 seconds of pressing. The substrate was then exposed to light using a high-pressure mercury lamp with aperture patterns of 40, 50, 60, and 70 μm diameter. The exposure dose was adjusted to achieve 10 gloss levels using a step tablet (Photec 41-step). After the exposure, the first film was peeled off from the resin layer (including the cured product) of the dry film to expose the resin layer. Then, a 1% by mass Na2CO3 aqueous solution at 30°C was sprayed at a pressure of 2 kg / cm 2 This substrate was then exposed to a UV conveyor furnace at an integrated exposure dose of 1000 mJ / cm for 30 seconds. 2 After irradiating with ultraviolet light under the conditions, the substrate was heated and cured at 150°C for 60 minutes. The appearance of the area around the opening of the test substrate produced according to this production process was observed using an optical microscope. The evaluation method was as follows. The evaluation results are shown in Table 2. A ◎ or ○ was considered to be acceptable. [Evaluation criteria] ◎: No residue was observed for any opening size. ◯: No residue was observed at openings of Φ50 or more. ×: Residue was observed in all sizes from Φ40 to Φ70. XX: The opening could not be patterned.

[0155] <Evaluation of insulation reliability> The second film was peeled off from the resin layer of the dry film prepared in the above (preparation of dry film), and etched with CZ-8101B at an etching rate of 1.0 μm / m 2A resin layer was bonded to a substrate with a comb-shaped pattern of L / S = 20 / 20 μm formed under the above conditions, and then laminated using a vacuum laminator (CVP-300, manufactured by Nikko Materials Co., Ltd.) in a first chamber at 90°C under conditions of a vacuum pressure of 3 hPa and a vacuum time of 30 seconds. Pressing was then performed under conditions of a pressure of 0.5 MPa and a press time of 30 seconds. Next, the entire surface was exposed to light using an exposure device equipped with a high-pressure mercury lamp. The exposure dose was adjusted to achieve a gloss sensitivity of 10 steps using a step tablet (Photec 41 steps). After exposure, the first film was peeled off from the resin layer (including the cured product) of the dry film, exposing the resin layer. Then, a 1% by mass Na2CO3 aqueous solution at 30°C was sprayed at a pressure of 2 kg / cm. 2 This substrate was then exposed to a UV conveyor furnace at an integrated exposure dose of 1000 mJ / cm for 30 seconds. 2 After irradiating with ultraviolet light under the above conditions, the sample was heat-cured at 150°C for 60 minutes. After that, electrodes were connected and a HAST test was carried out under the conditions of 130°C, RH 85%, and 5V. The evaluation method is as follows. The evaluation results are shown in Table 2. [Evaluation criteria] ○: No malfunctions up to 150 hours ×: Failure occurs within 150 hours

[0156] [Table 2]

[0157] From the results in Table 2, it was confirmed that the curable resin compositions of each Example all had excellent insulation reliability and reduced development residues. It is believed that the curable resin compositions of each Example exhibited excellent insulation reliability because they used the carboxyl group-containing resin of Synthesis Example 1, which had a reduced chlorine content. Comparing Comparative Example 1 and Example 2, Example 2 contained 0.6% by mass of elastomer, and therefore the development residue was reduced compared to Comparative Example 1, which did not contain elastomer. This is thought to be because the stress relaxation effect of the elastomer suppresses aggregation and orientation of the curable resin composition, thereby reducing the development residue. Similarly, when comparing Comparative Example 2 and Example 3, Example 3 had a lower development residue than Comparative Example 2, in which the elastomer content was 55% by mass. This is thought to be because when the elastomer content exceeds 50% by mass, the curable resin composition becomes more susceptible to swelling and peeling, resulting in an increase in development residue. For this reason, the curable resin composition of the present invention exhibits excellent insulation reliability by using a carboxyl group-containing resin with a low content of impurities such as chlorine, and development residues can be reduced by using a predetermined amount of elastomer.

Claims

1. A curable resin composition comprising a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component, and an elastomer, The 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 content of the elastomer is 0.1% by mass or more and 50% by mass or less 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 elastomer comprises at least one of a core-shell type rubber particle and a non-particle elastomer.

3. 3. The curable resin composition according to claim 2, wherein a constituent material of the core layer of the core-shell type rubber particle is at least one selected from the group consisting of a silicone-based elastomer, a butadiene-based elastomer, a styrene-based elastomer, an acrylic-based elastomer, a polyolefin-based elastomer, a silicone / acrylic-based composite elastomer, and a (meth)acrylate-based polymer.

4. 3. The curable resin composition according to claim 2, wherein the non-particle elastomer is at least one selected from the group consisting of polyester-based elastomers, polyurethane-based elastomers, polyesterurethane-based elastomers, polyamide-based elastomers, polyesteramide-based elastomers, acrylic-based elastomers, and olefin-based elastomers.

5. The curable resin composition according to claim 1, wherein the content of the carboxyl group-containing resin is 10% by mass or more and 60% by mass or less in terms of solid content with respect to the total amount of the curable resin composition.

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

7. 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 6.

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

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

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

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

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