JP2018045030A - Photosensitive resin composition and coated printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition from which such a solder resist layer can be formed that has sufficient alkali developability and UV sensitivity and has excellent electric insulation reliability, PCT durability and whitening durability.SOLUTION: The photosensitive resin composition comprises a carboxyl group-containing resin, a photopolymerization initiator, a photopolymerizable compound, and an epoxy compound. The carboxyl group-containing resin comprises a carboxyl group-containing resin (A-1) that is a reaction product of an epoxy resin having a novolac structure with an unsaturated carboxylic acid and a polybasic acid, and a carboxyl group-containing resin (A-2) that is a reaction product of an intermediate as a reaction product of an epoxy resin having a phenol novolac structure and an unsaturated carboxylic acid, and a polybasic acid anhydride.SELECTED DRAWING: None

Description

  The present invention relates to a photosensitive resin composition and a coated printed wiring board, and more specifically, a photosensitive resin composition used for forming a solder resist layer in a printed wiring board, and the photosensitive resin composition. The present invention relates to a coated printed wiring board provided with a solder resist layer.

  In order to form a solder resist layer in a printed wiring board, various photosensitive resin compositions are used. The solder resist layer is formed by irradiating the coating film of the photosensitive resin composition with ultraviolet rays (hereinafter also referred to as UV) and curing it.

  For example, Patent Document 1 discloses that ultraviolet rays are applied to a coating film of a photosensitive resin composition containing a composition obtained by reacting a polybasic acid anhydride with a reaction product of a novolak epoxy compound and an unsaturated monocarboxylic acid. It is disclosed that a coating film is cured by irradiation to form a solder resist layer.

Japanese Patent Laid-Open No. 01-141904

  In recent years, further increases in the density of conductor wiring in printed wiring boards and further improvement in the reliability of solder resist layers have been demanded. However, it is difficult for the photosensitive resin composition described in Patent Document 1 to ensure sufficient alkali developability to cope with the increase in the density of the conductor wiring, and high electrical insulation reliability required in recent years. It was also difficult to form a solder resist layer having PCT (pressure cooker test) resistance and whitening resistance.

  Moreover, when irradiating a coating film of the photosensitive resin composition with ultraviolet rays, various light sources are used, and depending on the light source, the irradiation amount of ultraviolet rays to the coating film (hereinafter also referred to as exposure amount) may be reduced. When the exposure dose is small and the UV sensitivity of the photosensitive resin composition is low, a solder resist layer having sufficient electrical insulation reliability, PCT resistance, and whitening resistance may not be formed. For this reason, improving the UV sensitivity of the photosensitive resin composition was also calculated | required.

  An object of the present invention is to provide a photosensitive resin composition capable of forming a solder resist layer having sufficient alkali developability and UV sensitivity, and having excellent electrical insulation reliability, PCT resistance, and whitening resistance, and this photosensitive resin composition. It is providing the covering printed wiring board provided with the soldering resist layer formed from the adhesive resin composition.

The photosensitive resin composition according to an embodiment of the present invention includes a carboxyl group-containing resin (A),
A photopolymerization initiator (B);
A photopolymerizable compound (C);
An epoxy compound (D),
The carboxyl group-containing resin (A) contains a carboxyl group-containing resin (A-1) and a carboxyl group-containing resin (A-2),
The carboxyl group-containing resin (A-1) is a reaction product of an epoxy resin (a11) having a novolak structure, an unsaturated carboxylic acid (a12) and a polybasic acid (a13),
The carboxyl group-containing resin (A-2) includes an intermediate that is a reaction product of an epoxy resin (a21) having a phenol novolak structure and an unsaturated carboxylic acid (a22), and a polybasic acid anhydride (a23). It is a reactant.

  The coated printed wiring board which concerns on one Embodiment of this invention is equipped with the soldering resist layer which is a hardened | cured material of said photosensitive resin composition.

  According to the present invention, a photosensitive resin composition capable of forming a solder resist layer having sufficient alkali developability and UV sensitivity and having excellent electrical insulation reliability, PCT resistance, and whitening resistance, and this photosensitive resin composition. And a coated printed wiring board provided with a solder resist layer formed from a conductive resin composition.

  Hereinafter, modes for carrying out the present invention will be described.

  The photosensitive resin composition according to this embodiment contains a carboxyl group-containing resin (A), a photopolymerization initiator (B), a photopolymerizable compound (C), and an epoxy compound (D). Hereinafter, each component contained in the photosensitive resin composition will be described in detail.

1. Carboxyl group-containing resin (A)
The carboxyl group-containing resin (A) contains a carboxyl group-containing resin (A-1) and a carboxyl group-containing resin (A-2). The carboxyl group-containing resin (A-1) is a reaction product of an epoxy resin (a11) having a novolak structure, an unsaturated carboxylic acid (a12), and a polybasic acid (a13). The carboxyl group-containing resin (A-2) is a reaction between an intermediate that is a reaction product of an epoxy resin (a21) having a phenol novolak structure and an unsaturated carboxylic acid (a22), and a polybasic acid anhydride (a23). It is a thing.

  When the photosensitive resin composition contains the carboxyl group-containing resin (A-1), an excellent alkali developability can be imparted to the photosensitive resin composition, and the solder resist layer formed from the photosensitive resin composition In addition, excellent electrical insulation reliability and PCT resistance can be imparted. Furthermore, when the photosensitive resin composition contains the carboxyl group-containing resin (A-2), sufficient UV sensitivity of the photosensitive resin composition can be secured, and whitening resistance can be imparted.

  Thus, the photosensitive resin composition of this embodiment contains sufficient carboxyl developability and UV sensitivity by containing both the carboxyl group-containing resin (A-1) and the carboxyl group-containing resin (A-2). And having excellent electrical insulation reliability, PCT resistance, and whitening resistance can be imparted to a solder resist layer produced from the photosensitive resin composition.

  The ratio of the carboxyl group-containing resin (A) to the solid content of the photosensitive resin composition is, for example, in the range of 20 to 60% by weight, and preferably in the range of 25 to 55% by weight.

  The carboxyl group-containing resin (A) may contain only the carboxyl group-containing resin (A-1) and the carboxyl group-containing resin (A-2), or the carboxyl group-containing resin (A-1) and the carboxyl group. In addition to the containing resin (A-2), other carboxyl group-containing resins may be contained.

1-1. Carboxyl group-containing resin (A-1)
As described above, the carboxyl group-containing resin (A-1) is a reaction product of an epoxy resin (a11) having a novolak structure, an unsaturated carboxylic acid (a12), and a polybasic acid (a13). In this carboxyl group-containing resin (A-1), an unsaturated carboxylic acid (a12) is added to a part of the epoxy groups of the epoxy resin (a11), and a polybasic acid is added to another part of the epoxy groups. (A13) has the added structure.

  The epoxy resin (a11) has a structure represented by the following formula (1), for example. X in the formula (1) is a divalent hydrocarbon group, and R is hydrogen or an alkyl group. The epoxy resin (a11) contains, for example, at least one component selected from the group consisting of a cresol novolac epoxy resin, a phenol novolac epoxy resin, and a biphenyl novolac epoxy resin. The cresol novolac type epoxy resin has a structure in which, for example, R and X in the formula (1) are a methyl group and a methylene group, respectively. The phenol novolac type epoxy resin has a structure in which, for example, R and X in the formula (1) are hydrogen and a methylene group, respectively. The biphenyl novolac type epoxy resin may have a structure in which, for example, R and X in the formula (1) are hydrogen and biphenyl groups, respectively, and R and X are respectively connected to hydrogen and biphenyl groups and both ends thereof. It may have a structure consisting of two methylene groups.

  The epoxy resin (a11) preferably contains at least one component selected from the group consisting of a cresol novolac type epoxy resin and a biphenyl novolac type epoxy resin, and more preferably contains a cresol novolac type epoxy resin.

  The epoxy resin (a11) is not limited to the resin having the structure represented by the above formula (1). For example, the novolac epoxy resin having a cyclopentadiene skeleton, the novolak epoxy resin having a naphthalene skeleton, and the bisphenol skeleton are used. You may contain the at least 1 type of component selected from the group which consists of the novolak-type epoxy resin which has.

  Examples of components contained in the unsaturated carboxylic acid (a12) include a compound having only one ethylenically unsaturated group and a compound having a plurality of ethylenically unsaturated groups. Examples of compounds having only one ethylenically unsaturated group are acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid 2-methacryloyloxyethyl phthalic acid, β-carboxyethyl acrylate, acryloyloxyethyl succinate, methacryloyloxyethyl succinate, 2-propenoic acid, 3- (2-carboxyethoxy) -3-oxypropyl ester, 2 -Acryloyloxyethyl tetrahydrophthalic acid, 2-methacryloyloxyethyl tetrahydrophthalic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-methacryloyloxyethyl hexahydrophthalic acid, and ω-carbo Contains xyl-polycaprolactone monoacrylate. Examples of compounds having a plurality of ethylenically unsaturated groups are compounds obtained by reacting a difunctional acid anhydride with a polyfunctional acrylate having a hydroxyl group, and dibasic acid anhydrides on a polyfunctional methacrylate having a hydroxyl group. Includes compounds obtained by reaction. More specifically, examples of compounds having a plurality of ethylenically unsaturated groups include pentaerythritol triacrylate, pentaerythritol trimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, dipentaerythritol pentaacrylate, and dipenta Contains erythritol pentamethacrylate. Unsaturated carboxylic acid (a12) can contain 1 type, or 2 or more types among these components. In particular, the unsaturated carboxylic acid (a12) preferably contains one or more components selected from the group consisting of acrylic acid and methacrylic acid. In this case, the stickiness of the wet coating film formed from the photosensitive resin composition is sufficiently suppressed, and the plating resistance and solder heat resistance of the solder resist layer are improved.

  The polybasic acid (a13) is preferably a polycarboxylic acid, more preferably a dicarboxylic acid. Examples of components contained in the polybasic acid (a13) are oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, Contains isophthalic acid, terephthalic acid, tetrahydrophthalic acid, methanetricarboxylic acid, tricarballylic acid, benzenetricarboxylic acid, benzenetetracarboxylic acid. The polybasic acid (a13) can contain one or more of these components. In particular, the polybasic acid (a13) preferably contains one or more components selected from the group consisting of malonic acid, glutaric acid, maleic acid, tetrahydrophthalic acid, and phthalic acid, and includes maleic acid, tetrahydrophthalic acid, and phthalic acid. More preferably, it contains one or more components selected from the group consisting of acids.

  The carboxyl group-containing resin (A-1) can be produced, for example, by the following method.

  First, the unsaturated carboxylic acid (a12) is reacted with the epoxy resin (a11). Thereby, as shown to following formula (2), unsaturated carboxylic acid (a12) adds to a part among epoxy groups of an epoxy resin (a11), and a 1st intermediate body produces | generates. For this reason, the first intermediate has a structure represented by the following formula (3) and an unreacted epoxy group. Since the first intermediate has a structure represented by the following formula (3), the first intermediate has a secondary hydroxyl group in the side chain. The addition reaction of the following formula (2) is preferably performed in a solvent in the presence of a polymerization inhibitor and a catalyst.

  X in the above formulas (2) and (3) represents an unsaturated carboxylic acid residue.

  Next, the first intermediate is reacted with the polybasic acid (a13). Thereby, as shown to following formula (4), a polybasic acid (a13) is added to the unreacted epoxy group which a 1st intermediate body has, and carboxyl group-containing resin (A-1) produces | generates. . For this reason, carboxyl group-containing resin (A-1) has a structure shown in following formula (5). For this reason, the carboxyl group-containing resin (A-1) has a secondary hydroxyl group in the side chain and a carboxyl group at the end of the side chain.

  Y in the formulas (4) and (5) represents a polybasic acid residue.

  In addition, at the time of reaction of a 1st intermediate body and a polybasic acid (a13), a polybasic acid (a13) is preferential with the unreacted epoxy group which an intermediate body has instead of the secondary hydroxyl group which an intermediate body has. To react. Therefore, carboxyl group-containing resin (A-1) has the structure shown in Formula (3) and the structure shown in Formula (5).

  In addition, when the carboxyl group-containing resin (A-1) has the structure represented by the formula (3) and the structure represented by the formula (5) as described above, an unsaturated carboxylic acid (a12) is added to the epoxy resin (a11). ) May be prepared by reacting polybasic acid (a13) at the same time, or reacting polybasic acid (a13) with epoxy resin (a11) and then reacting with unsaturated carboxylic acid (a12). May be manufactured.

  The carboxyl group-containing resin (A-1) includes a secondary hydroxyl group in the structure represented by the above formula (3) and a carboxyl group at the end of the side chain in the structure represented by the above formula (5). It is speculated that this is the reason why the carboxyl group-containing resin (A-1) can exhibit excellent developability when an alkaline solution is used as a developer. Further, the carboxyl group-containing resin (A-1) has an ethylenically unsaturated group at the end of the side chain in the structure represented by the above formula (3) and a terminal of the side chain in the structure represented by the above formula (5). It has a certain carboxyl group. This is presumed to be the reason why the carboxyl group can have high reactivity. Therefore, the solder resist layer produced from the photosensitive resin composition can have high electrical insulation reliability and high PCT resistance.

  Examples of the solvent used in the synthesis of the carboxyl group-containing resin (A-1) are ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; ethylene glycol monoethyl ether, ethylene Glycol ethers such as glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether Ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate Acetic esters such as ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate; alcohols such as ethanol, propanol, ethylene glycol, propylene glycol; octane And aliphatic hydrocarbons such as decane; and petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. Of these organic solvents, only one type may be used, or two or more types may be used in combination.

  Examples of the catalyst used in the synthesis of the carboxyl group-containing resin (A-1) include tertiary amines such as triethylamine, quaternary ammonium salts such as triethylbenzylammonium chloride, and imidazole compounds such as 2-ethyl-4-methylimidazole. And phosphorus compounds such as triphenylphosphine and metal salts of organic acids such as naphthenic acid, lauric acid, stearic acid, oleic acid and octoenoic acid such as lithium, chromium, zirconium, potassium and sodium. Among these catalysts, only one type may be used or two or more types may be used in combination.

  Examples of the polymerization inhibitor used in the synthesis of the carboxyl group-containing resin (A-1) include hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, catechol, pyrogallol, and phenothiazine. Among these polymerization inhibitors, only one kind may be used or two or more kinds may be used in combination.

  The amount of the unsaturated carboxylic acid (a12) relative to 1 mol of the epoxy group of the epoxy resin (a11) when the epoxy resin (a11) and the unsaturated carboxylic acid (a12) are reacted is within the range of 0.2 to 0.8 mol. It is preferable that it is within a range of 0.3 to 0.7 mol. Moreover, the quantity of polybasic acid (a13) with respect to 1 mol of epoxy groups of epoxy resin (a11) at the time of making a 1st intermediate body and polybasic acid (a13) react is in the range of 0.2-0.8 mol. It is preferable that it is within a range of 0.3 to 0.7 mol. That is, the unsaturated carboxylic acid (a12) is in the range of 0.2 to 0.8 mol and the polybasic acid (a13) is 0.2 to 0.8 mol with respect to 1 mol of the epoxy group of the epoxy resin (a11). It is preferable to be within the range. Moreover, unsaturated carboxylic acid (a12) exists in the range of 0.3-0.7 mol with respect to 1 mol of epoxy groups of an epoxy resin (a11), and polybasic acid (a13) is 0.3-0.7 mol. More preferably within the range. In this case, the improvement of the UV sensitivity of the photosensitive resin composition and the securing of alkali developability can be easily achieved.

  The ratio of the carboxyl group-containing resin (A-1) to the entire carboxyl group-containing resin (A) is preferably 15% by mass or more, more preferably 25% by mass or more, and further preferably 35% by mass or more. Especially preferably, it is 45 mass% or more. Although the upper limit of the ratio of carboxyl group-containing resin (A-1) with respect to the whole carboxyl group-containing resin (A) is not specifically limited, For example, it is 92 mass% or less, Preferably it is 84 mass% or less.

1-2. Carboxyl group-containing resin (A-2)
The carboxyl group-containing resin (A-2) is an intermediate (hereinafter also referred to as a second intermediate) that is a reaction product of an epoxy resin (a21) having a phenol novolak structure and an unsaturated carboxylic acid (a22). It is a reaction product with polybasic acid anhydride (a23).

  The epoxy resin (a21) having a phenol novolac structure has, for example, a structure in which X in the above formula (1) is a methylene group and R is hydrogen.

  The example of the component contained in unsaturated carboxylic acid (a22) is the same as the example of the component contained in said unsaturated carboxylic acid (a12).

  Examples of components contained in the polybasic acid anhydride (a23) are methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, nadic anhydride, 3,6-endomethylenetetrahydro Alicyclic dibasic acid anhydrides such as phthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, tetrabromophthalic anhydride; succinic anhydride, maleic anhydride, itaconic anhydride, octenyl succinic anhydride, pentadodecenyl succinic anhydride, anhydrous Aliphatic or aromatic dibasic acid anhydrides such as phthalic acid and trimellitic anhydride, biphenyl tetracarboxylic dianhydride, diphenyl ether tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, cyclopentane tetracarboxylic acid di Anhydride, pyromellitic anhydride, ben Including phenone dianhydride and aliphatic tetracarboxylic acid dianhydride, and benzophenone tetracarboxylic acid dianhydride and aromatic tetracarboxylic acid dianhydride. The polybasic acid anhydride (a23) can contain one or more of these components.

  The carboxyl group-containing resin (A-2) is produced, for example, by the following reaction.

  First, the epoxy resin (a21) and the unsaturated carboxylic acid (a22) are reacted. Thereby, as shown to following formula (6), unsaturated carboxylic acid (a22) is added to the epoxy group of an epoxy resin (a21), and a 2nd intermediate body produces | generates. For this reason, the second intermediate has a structure represented by the following formula (7) and an unreacted epoxy group. All epoxy groups may be reacted, i.e. the second intermediate may not have unreacted epoxy groups. The second intermediate has a secondary hydroxyl group in the side chain in the structure represented by the following formula (7). This addition reaction is preferably performed in a solvent in the presence of a polymerization inhibitor and a catalyst.

  X in the formulas (6) and (7) represents an unsaturated carboxylic acid residue.

  Next, the second intermediate is reacted with the polybasic acid anhydride (a23). Thereby, as shown in the following formula (8), the secondary hydroxyl group and the polybasic acid anhydride are obtained by an esterification reaction between the secondary hydroxyl group of the second intermediate and the polybasic acid anhydride (a23). A carboxyl group-containing resin (A-2) having an ester bond with the product (a23) is produced. For this reason, carboxyl group-containing resin (A-2) has a structure shown in following formula (9). For this reason, carboxyl group-containing resin (A-2) has a carboxyl group in the side chain in the structure shown in Formula (9).

  The second intermediate may have an unreacted epoxy group, but at the time of the reaction between the second intermediate and the polybasic acid anhydride (a23), the polybasic acid anhydride (a23) Reacts preferentially with secondary hydroxyl groups rather than groups. This is because when a secondary hydroxyl group and an epoxy group coexist, the polybasic acid anhydride (a23) is very difficult to react with the epoxy group and very easily reacts with the secondary hydroxyl group. is there.

  In formulas (8) and (9), A represents an unsaturated carboxylic acid residue, and B represents a polybasic acid anhydride residue. When the polybasic acid anhydride is an acid dianhydride, the polybasic acid anhydride reacts with two hydroxyl groups to form a crosslinked structure and generate two carboxyl groups.

  The carboxyl group-containing resin (A-2) has an ethylenically unsaturated bond and a carboxyl group in the side chain in the structure represented by the above formula (9). Since this carboxyl group-containing resin (A-2) does not have a substituent such as a methyl group other than the side chain on the benzene ring, the steric hindrance is small. Therefore, the carboxyl group-containing resin (A-2) can increase the UV sensitivity of the photosensitive resin composition. Furthermore, since the carboxyl group-containing resin (A-2) is likely to have a three-dimensional structure by polymerization, the carboxyl group-containing resin (A-2) is a cured product produced by UV curing of the photosensitive resin composition. Crosslinking density can be increased and high whitening resistance can be achieved.

  Examples of the solvent used in the synthesis of the carboxyl group-containing resin (A-2) include aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol mono Glycol ethers such as butyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether; and ethyl acetate, butyl acetate , Ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate DOO, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, include acetic acid esters such as propylene glycol monomethyl ether acetate. Of these solvents, only one type may be used, or two or more types may be used in combination.

  Examples of the polymerization inhibitor used in the synthesis of the carboxyl group-containing resin (A-2) include hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, catechol, pyrogallol, and phenothiazine. Among these polymerization inhibitors, only one kind may be used, or two or more kinds may be used in combination.

  Examples of the catalyst used in the synthesis of the carboxyl group-containing resin (A-2) include tertiary amines such as triethylamine, quaternary ammonium salts such as triethylbenzylammonium chloride, and imidazoles such as 2-ethyl-4-methylimidazole. Compounds and phosphorus compounds such as triphenylphosphine are included. Of these catalysts, only one type may be used, or two or more types may be used in combination.

  When the epoxy resin (a21) and the unsaturated carboxylic acid (a22) are reacted, the amount of the unsaturated carboxylic acid (a22) with respect to 1 mol of the epoxy group of the epoxy resin (a21) is within a range of 0.8 to 1.2 mol. It is preferable that it is within a range of 0.9 to 1.1 mol. Moreover, the amount of the polybasic acid anhydride (a23) relative to 1 mol of the epoxy group of the epoxy resin (a21) when the second intermediate and the polybasic acid anhydride (a23) are reacted is 0.2 to 0.8 mol. Is preferably in the range of 0.3 to 0.7 mol. That is, the unsaturated carboxylic acid (a22) is in the range of 0.8 to 1.2 mol and the polybasic acid anhydride (a23) is 0.2 to 0 with respect to 1 mol of the epoxy group of the epoxy resin (a21). It is preferable to be within the range of .8 mol. Moreover, unsaturated carboxylic acid (a22) exists in the range of 0.9-1.1 mol with respect to 1 mol of epoxy groups of an epoxy resin (a21), and polybasic acid anhydride (a23) is 0.3-0. More preferably, it is in the range of 7 mol. In this case, the improvement of the UV sensitivity of the photosensitive resin composition and the securing of the alkali developability of the photosensitive resin composition can be easily achieved.

  The ratio of the carboxyl group-containing resin (A-2) to the entire carboxyl group-containing resin (A) is preferably 8% by mass or more, more preferably 12% by mass or more, and further preferably 16% by mass or more. Especially preferably, it is 20 mass% or more. Although the upper limit of the ratio of carboxyl group-containing resin resin (A-2) with respect to the whole carboxyl group-containing resin (A) is not particularly limited, it is, for example, 85% by mass or less, and preferably 70% by mass or less.

2. Photopolymerization initiator (B)
The photopolymerization initiator (B) is a compound that generates a radical, a cation, an anion, or the like when irradiated with ultraviolet rays or an electron beam, and triggers a polymerization reaction. The photopolymerization initiator (B) is preferably a compound that generates radicals when irradiated with ultraviolet rays. The photopolymerization initiator (B) includes, for example, benzoin and its alkyl ethers; acetophenones such as acetophenone and benzyldimethyl ketal; anthraquinones such as 2-methylanthraquinone; 2,4-dimethylthioxanthone and 2,4-diethylthioxanthone Thioxanthones such as 2-isopropylthioxanthone, 4-isopropylthioxanthone, and 2,4-diisopropylthioxanthone; benzophenones such as benzophenone and 4-benzoyl-4′-methyldiphenyl sulfide; and xanthones such as 2,4-diisopropylxanthone; Nitrogen-containing initiators such as 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one; 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl -1-phenyl-propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- { Α-hydroxyalkylphenones such as 4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, phenylglyoxylic acid methyl ester; Methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2- (dimethylamino) Α-aminoalkylphenones such as 2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone; 2 Monoacylphosphine oxide photoinitiators such as 4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,4,6-trimethylbenzoyl-ethyl-phenyl-phosphinate; and bis- (2,4,6-trimethyl) Benzoyl) -phenylphosphine oxide, bis- (2,6-dichlorobenzoyl) phenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) ) -4-propylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -1-naphthylphosphine oxide, bis- (2,6-dimethoxybenzoyl) phenylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,5-dimethylphenylphosphine oxide, (2,5,6-trimethylbenzoyl) -2,4,4-trimethyl Acylphosphine photopolymerization initiators such as pentylphosphine oxide; 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6 It can contain at least one compound selected from the group consisting of oxime ester photopolymerization initiators such as-(2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime). The photopolymerization initiator (B) preferably contains an acylphosphine oxide photopolymerization initiator. In this case, the insulation reliability of the solder resist layer formed from the photosensitive resin composition can be improved, and the UV sensitivity of the photosensitive resin composition can be improved. In particular, the photopolymerization initiator (B) is one or more selected from the group consisting of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide. It is more preferable to contain this compound. In this case, the UV sensitivity of the photosensitive resin composition can be particularly improved.

  The ratio of the photopolymerization initiator (B) to the carboxyl group-containing resin (A) is preferably in the range of 0.01 to 50% by mass, more preferably in the range of 0.1 to 25% by mass, More preferably, it exists in the range of 1-20 mass%.

3. Photopolymerizable compound (C)
The photopolymerizable compound (C) is a compound having an ethylenically unsaturated double bond. The photopolymerizable compound (C) can impart photocurability to the photosensitive resin composition. The photopolymerizable compound (C) is, for example, a monofunctional (meth) acrylate such as 2-hydroxyethyl (meth) acrylate; and diethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meta) ) Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ε-caprolactone modified pentaerythritol hexaacrylate, etc. It can contain at least one compound selected from the group consisting of (meth) acrylates.

  The photopolymerizable compound (C) may contain a trifunctional compound, that is, a compound having three unsaturated bonds in one molecule. In this case, the resolution in the case of exposing and developing a film formed from the resin composition is improved, and the developability of the resin composition with an alkaline aqueous solution is particularly improved. Trifunctional compounds include, for example, trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethoxylated isocyanuric acid tri (meth) acrylate and ε-caprolactone modified It can contain at least one compound selected from the group consisting of tris- (2-acryloxyethyl) isocyanurate and ethoxylated glycerin tri (meth) acrylate.

  The photopolymerizable compound (C) may contain a phosphorus-containing compound (phosphorus-containing unsaturated compound). In this case, the flame retardancy of the cured product of the resin composition is improved. Phosphorus-containing unsaturated compounds include, for example, 2-methacryloyloxyethyl acid phosphate (as specific examples, product number light ester P-1M and light ester P-2M manufactured by Kyoeisha Chemical Co., Ltd.), 2-acryloyloxyethyl acid phosphate (As a specific example, product number light acrylate P-1A manufactured by Kyoeisha Chemical Co., Ltd.), diphenyl-2-methacryloyloxyethyl phosphate (as a specific example, product number MR-260 manufactured by Daihachi Kogyo Co., Ltd.), and Showa Polymer Co., Ltd. HFA series (part number HFA-6003 which is an addition reaction product of dipentaerystol hexaacrylate and HCA (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) as a specific example, and HFA-6007, caprolactone And at least one compound selected from the group consisting of HFA-3003, HFA-6127, etc., which is an addition reaction product of modified dipentaerystol hexaacrylate and HCA).

  The photopolymerizable compound (C) may contain a prepolymer. The prepolymer is, for example, at least selected from the group consisting of prepolymers obtained by adding an ethylenically unsaturated group after polymerizing a monomer having an ethylenically unsaturated bond, and oligo (meth) acrylate prepolymers One kind can be contained. Oligo (meth) acrylate prepolymers include, for example, epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) acrylate, alkyd resin (meth) acrylate, silicone resin (meth) acrylate, and spirane resin (meth) acrylate At least one selected from the group consisting of:

  The ratio of the photopolymerizable compound (C) to the carboxyl group-containing resin (A) is preferably in the range of 5 to 50% by mass, more preferably in the range of 7 to 40% by mass, and still more preferably 9 It is in the range of ˜35% by mass.

4). Epoxy compound (D)
The epoxy compound (D) can impart thermosetting properties to the photosensitive resin composition. The epoxy compound (D) preferably has at least one epoxy group in one molecule, and preferably has at least two epoxy groups in one molecule. The epoxy compound (D) may be a solvent-insoluble epoxy compound or a general-purpose solvent-soluble epoxy compound. The kind of epoxy compound (D) is not specifically limited. The epoxy compound (D) is a phenol novolac type epoxy resin (specifically, product number EPICLON N-775 manufactured by DIC Corporation), a cresol novolac type epoxy resin (specifically, product number EPICLON N-695 manufactured by DIC Corporation), bisphenol. A type epoxy resin (specifically, product number jER1001 manufactured by Mitsubishi Chemical Corporation), bisphenol A-novolak type epoxy resin (specifically, product number EPICLON N-865 manufactured by DIC Corporation), bisphenol F type epoxy resin (specific examples) Mitsubishi Chemical Corporation product number jER4004P), bisphenol S type epoxy resin (specific example, product number EPICLON EXA-1514 made by DIC Corporation), bisphenol AD type epoxy resin, biphenyl type epoxy resin (specific As an example, Mitsubishi Chemical Corporation product number YX4000), biphenyl novolac type epoxy resin (as a specific example, Nippon Kayaku Co., Ltd. product number NC-3000), hydrogenated bisphenol A type epoxy resin (as a specific example, Nippon Steel & Sumikin Chemical Co., Ltd.) Manufactured product number ST-4000D), naphthalene type epoxy resin (specifically, product numbers EPICLON HP-4032, EPICLON HP-4700, EPICLON HP-4770 manufactured by DIC Corporation), tertiary butyl catechol type epoxy resin (specific example: DIC) Product number EPICLON HP-820 manufactured by Co., Ltd., dicyclopentadiene type epoxy resin (specific example, product number EPICLON HP-7200 manufactured by DIC), adamantane type epoxy resin (specific example, product number ADAM manufactured by Idemitsu Kosan Co., Ltd.) NTATE X-E-201), biphenyl ether type epoxy resin (as a specific example, product number YSLV-80DE manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., special bifunctional type epoxy resin (as a specific example, product number YL7175-500 manufactured by Mitsubishi Chemical Corporation) , And YL7175-1000; DIC Corporation part numbers EPICLON TSR-960, EPICLON TER-601, EPICLON TSR-250-80BX, EPICLON 1650-75MPX, EPICLON EXA-4850, EPICLON EXA-4816, EPICLON EXA-4816 EPICLON EXA-9726; product number YSLV-120TE manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., 1,3,5-tris (2,3-epoxypropyl) -1,3,5-triazine-2,4 , 6 (1H, 3H, 5H) -trione, and at least one compound selected from the group consisting of bisphenol-based epoxy resins other than those described above.

  In this embodiment, it is preferable that an epoxy compound (D) contains a crystalline epoxy resin. In this case, the developability of the coating film formed from the photosensitive resin composition with an alkaline aqueous solution can be improved, and the photosensitive resin composition is an alkali containing at least one of an alkali metal salt and an alkali metal hydroxide. It can be developed with an aqueous solution. Examples of crystalline epoxy resins include 1,3,5-tris (2,3-epoxypropyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) trione, hydroquinone type crystals Epoxy resin (specifically, product name YDC-1312 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), biphenyl type crystalline epoxy resin (specifically, product number YX-4000 manufactured by Mitsubishi Chemical Corporation), diphenyl ether type crystalline epoxy resin (specific example) As an example, Nippon Steel & Sumikin Chemical Co., Ltd. product number YSLV-80DE), bisphenol type crystalline epoxy resin (as a specific example, Nippon Steel & Sumikin Chemical Co., Ltd. product number YSLV-80XY), tetrakisphenol ethane type crystalline epoxy resin (as a specific example Nippon Kayaku Co., Ltd. product number GTR-1800), bisphenolfluorene type crystalline Carboxymethyl contained resin (epoxy resin having a structure represented by the formula (7) as a specific example).

  The ratio of the epoxy compound (D) to the carboxyl group-containing resin (A) is preferably within a range of 3 to 70% by mass, more preferably within a range of 5 to 60% by mass, and further preferably 10 to 50%. It is in the range of mass%. When the epoxy compound (D) contains a crystalline epoxy resin, the ratio of the crystalline epoxy resin to the carboxyl group-containing resin (A) is preferably in the range of 1% by mass to 70% by mass. It is more preferably in the range of mass% to 60 mass%, further preferably in the range of 5 mass% to 50 mass%, and particularly preferably in the range of 10 mass% to 40 mass%.

5. Ingredient (E)
The photosensitive resin composition includes components other than the above-mentioned carboxyl group-containing resin (A), photopolymerization initiator (B), photopolymerizable compound (C), and epoxy compound (D) (hereinafter referred to as component (E)). Say). Examples of the component (E) include a colorant, an adhesion-imparting agent, an organic solvent, an inorganic filler, a curing agent, other resins, and additives.

5-1. Colorant The photosensitive resin composition may contain a colorant. In this case, a color can be imparted to the film formed from the photosensitive resin composition. The colorant may contain, for example, a blue colorant and a yellow colorant. In this case, the color of the film formed from the photosensitive resin composition can be green. The colorant can include both pigments and dyes. For this reason, the blue colorant may be a pigment or a dye. The yellow colorant may be a pigment or a dye. The green colorant may be a pigment or a dye. The pigment may be inorganic particles or organometallic particles. The pigment may be dispersed in the solder resist composition. The dye may be an organic compound. The dye may be one that dissolves in the solder resist composition.

  Examples of blue colorants include phthalocyanine blue colorants and anthraquinone blue colorants. Examples of the phthalocyanine blue colorant include, for example, metal-substituted or unsubstituted phthalocyanine compounds. The blue colorant is preferably a pigment. Specific examples of blue colorants include: Pigment Blue 15; Pigment Blue 15: 1; Pigment Blue 15: 2; Pigment Blue 15: 3; Pigment Blue 15: 4; Pigment Blue 15: 6; Pigment Blue 16; Can be mentioned.

  Examples of yellow colorants include monoazo yellow colorants, disazo yellow colorants, condensed azo yellow colorants, benzimidazolone yellow colorants, isoindolinone yellow colorants, and anthraquinone yellow colorants. included. Specific examples of the yellow colorant (E2) include Pigment Yellow 24; Pigment Yellow 108; Pigment Yellow 193; Pigment Yellow 147; Pigment Yellow 150; Pigment Yellow 199; Pigment Yellow 202; Pigment Yellow 110; Pigment Yellow 179; Pigment Yellow 185; Pigment Yellow 93; Pigment Yellow 94; Pigment Yellow 95; Pigment Yellow 128; Pigment Yellow 155; Pigment Yellow 166; Pigment Yellow 180; 156; Pigment Yellow 175; and Pigment Yellow 181. Specific examples of 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; and Pigment Yellow 12, 13, 14, 16, 17, 55, 63, 81, 83, 87, 126, 127, 152, 170, 172, 174, 176, 188, and 198 are also included.

  The colorant is appropriately selected according to the color of the target film and the color of the insulating layer of the printed wiring board. The colorant is a kind selected from the group consisting of, for example, a blue colorant, a yellow colorant, a black colorant, a white colorant, a red colorant, a green colorant, a purple colorant, an orange colorant, and a brown colorant. The above materials may be included.

5-2. Adhesion imparting agent The photosensitive resin composition may contain an adhesion imparting agent. Examples of adhesion-imparting agents include melamine, anamine, acetoguanamine, benzoguanamine, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-4,6-diamino-S-triazine, 2 S-triazine derivatives such as vinyl-4,6-diamino-S-triazine / isocyanuric acid adduct and 2,4-diamino-6-methacryloyloxyethyl-S-triazine / isocyanuric acid adduct are included. In this case, the adhesiveness with the board | substrate of the soldering resist layer formed from the photosensitive resin composition can be improved.

5-3. Organic solvent The photosensitive resin composition may contain an organic solvent. Examples of organic solvents include linear, branched, secondary or polyhydric alcohols such as ethanol, propyl alcohol, isopropyl alcohol, hexanol and ethylene glycol; ketones such as methyl ethyl ketone and cyclohexanone; aromatics such as toluene and xylene Hydrocarbons: Petroleum-based aromatic solvents such as Swazol series (manufactured by Maruzen Petrochemical Co., Ltd.) and Solvesso series (manufactured by Exxon Chemical Co.); cellosolves such as cellosolve and butylcellosolve; Carbitols; diethylene glycol acetates such as diethylene glycol monoethyl ether acetate; propylene glycol alkyl ethers such as propylene glycol methyl ether; polypropylene such as dipropylene glycol methyl ether Glycol alkyl ethers; included and dialkyl glycol ethers are; ethyl acetate, butyl acetate, cellosolve acetate, acetic acid esters such as carbitol acetate. The amount of the organic solvent is preferably adjusted so that when the coating film of the photosensitive resin composition is dried, the organic solvent is volatilized quickly, that is, the organic solvent does not remain in the film. In particular, the organic solvent is preferably in the range of 0 to 99.5% by mass and more preferably in the range of 15 to 60% by mass with respect to the total amount of the photosensitive resin composition. In addition, since the suitable ratio of an organic solvent changes with the formation methods of a coating film, it is preferable to adjust suitably according to the formation method of a coating film.

5-4. Inorganic filler The photosensitive resin composition may contain an inorganic filler. In this case, the curing shrinkage of the coating film formed from the photosensitive resin composition can be reduced. Examples of inorganic fillers include barium sulfate, crystalline silica, fine silica, nanosilica, carbon nanotubes, talc, bentonite, aluminum hydroxide, magnesium hydroxide, magnesium oxide, calcium carbonate, titanium oxide, hydrotalcite, clay, Calcium silicate, mica, potassium titanate, barium titanate, aluminum nitride, boron nitride, zinc borate, aluminum borate, montmorillonite and sepiolite are included. You may whiten the photosensitive resin composition and its hardened | cured material by making an inorganic filler contain white materials, such as a titanium oxide and a zinc oxide.

5-5. Curing agent The photosensitive resin composition may contain a curing agent for the epoxy resin. Examples of curing agents include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- ( Imidazole derivatives such as 2-cyanoethyl) -2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N-dimethylbenzylamine Amine compounds such as 4-methyl-N, N-dimethylbenzylamine; hydrazine compounds such as adipic hydrazide and sebacic acid hydrazide; phosphorus compounds such as triphenylphosphine; acid anhydrides; phenols; mercaptans; ; And Oni It may contain one or more components selected from the group consisting of unsalted. Examples of commercially available products of these components include 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ (both trade names of imidazole compounds) manufactured by Shikoku Kasei Co., Ltd., U-CAT3503N, U manufactured by San Apro Co., Ltd. -CAT3502T (all are trade names of blocked isocyanate compounds of dimethylamine), DBU, DBN, U-CATSA102, U-CAT5002 (all are bicyclic amidine compounds and salts thereof).

5-6. Other resins The photosensitive resin composition comprises tolylene diisocyanate, morpholine diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate blocked isocyanates blocked with caprolactam, oxime, malonic acid ester, etc .; melamine resin, n-butyl Amino resins such as butyl melamine resin, isobutyl melamine resin, butylated urea resin, butylated melamine urea co-condensation resin, benzoguanamine co-condensation resin; various other thermosetting resins; ultraviolet curable epoxy (meth) acrylate; Resins obtained by adding (meth) acrylic acid to epoxy resins such as bisphenol A type, phenol novolac type, cresol novolac type, and alicyclic type; and diallyl phthalate resin, phenoxy resin, urethane resin, You may contain 1 or more types of resin selected from the group which consists of high molecular compounds, such as a fluororesin.

5-7. Additives The photosensitive resin composition comprises a curing accelerator; a copolymer such as silicone and acrylate; a leveling agent; a thixotropic agent; a polymerization inhibitor; an antihalation agent; a flame retardant; an antifoaming agent; As well as one or more additives selected from the group consisting of polymeric dispersants.

  The photosensitive resin composition of this embodiment includes the carboxyl group-containing resin (A), the photopolymerization initiator (B), the photopolymerizable compound (C), and the epoxy compound (D), as necessary. It can manufacture by mixing a component (E).

  Specifically, the photosensitive resin composition can be prepared by blending the raw materials of the photosensitive resin composition as described above and kneading by a known kneading method using, for example, a three roll, ball mill, sand mill or the like. In the case where the raw material of the photosensitive resin composition contains a liquid component, a low viscosity component, etc., the part of the raw material excluding the liquid component, the low viscosity component, etc. is first kneaded, and the resulting mixture is The photosensitive resin composition may be prepared by adding and mixing a liquid component, a component having a low viscosity, and the like.

  In consideration of storage stability and the like, the first agent may be prepared by mixing a part of the components of the photosensitive resin composition, and the second agent may be prepared by mixing the rest of the components. That is, the photosensitive resin composition may include a first agent and a second agent. In this case, for example, among the components of the photosensitive resin composition, the photopolymerizable compound (C), the epoxy compound (D), and a part of the organic solvent are mixed in advance and dispersed to disperse the first agent. The second agent may be prepared by mixing and dispersing the remainder of the components of the photosensitive resin composition. In this case, it is possible to prepare a mixed solution by mixing the necessary amount of the first agent and the second agent in a timely manner and curing the mixed solution to obtain a cured product.

  The photosensitive resin composition of this embodiment is suitable as an electrically insulating material for a printed wiring board. In particular, the photosensitive resin composition is suitable for forming an electrically insulating layer such as a solder resist layer, a plating resist layer, an etching resist layer, and an interlayer insulating layer.

  Hereinafter, an example of a method for producing a coated printed wiring board provided with a solder resist layer formed from a photosensitive resin composition will be described.

  First, a core material is prepared. The core material includes, for example, at least one insulating layer and at least one conductor wiring. A film is formed from the photosensitive resin composition on the surface of the core material where the conductor wiring is provided. The film formation method is preferably a coating method. In the application method, for example, a photosensitive resin composition is applied on a core material to form a wet coating film. The method for applying the photosensitive resin composition is selected from the group consisting of known methods such as dipping, spraying, spin coating, roll coating, curtain coating, and screen printing. Subsequently, in order to volatilize the organic solvent in the wet coating film, the wet coating film is dried, for example, at a temperature in the range of 60 to 120 ° C., thereby obtaining a film.

The film is partially cured by exposure. Examples of the exposure method include a method in which a negative mask is applied to the film and then the film is irradiated with ultraviolet rays. The negative mask includes an exposure part that transmits ultraviolet light and a non-exposure part that blocks ultraviolet light. The negative mask is a photo tool such as a mask film or a dry plate. Examples of ultraviolet light sources include chemical lamps, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, metal halide lamps, LEDs, g-line (436 nm), h-line (405 nm), i-line (365 nm), and It is selected from the group consisting of a combination of two or more of g-line, h-line and i-line. The exposure method may be a method other than a method using a negative mask. For example, the film may be exposed by a direct drawing method in which only the portion of the film to be exposed is irradiated with ultraviolet rays emitted from a light source. For example, the preferable exposure amount range in the exposure step before the development step is preferably in the range of 30 to 1000 mJ / cm ² , more preferably in the range of 30 to 600 mJ / cm ² , and 30 to 400 mJ / cm ^2. More preferably within the range of cm ² .

  Subsequently, the film is subjected to development treatment to remove the unexposed portion of the film. In the development process, an appropriate developer according to the composition of the photosensitive resin composition can be used. The developer is, for example, an alkaline aqueous solution containing at least one of an alkali metal salt and an alkali metal hydroxide, or an organic amine. More specifically, the alkaline aqueous solution is, for example, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium hydroxide, potassium hydroxide, ammonium hydroxide, tetramethyl ammonium hydroxide and water. It contains at least one component selected from the group consisting of lithium oxide. The solvent in the alkaline aqueous solution may be water alone or a mixture of water and a hydrophilic organic solvent such as a lower alcohol. The organic amine contains, for example, at least one component selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine and triisopropanolamine.

  Subsequently, the film after the development process is heated. The heating conditions are, for example, within a heating temperature range of 120 to 200 ° C. and within a heating time range of 30 to 150 minutes. When the film is cured in this way, the performance of the solder resist layer such as strength, hardness, chemical resistance and the like is improved. If necessary, the film may be further irradiated with ultraviolet rays before or after heating. In this case, photocuring of the film can be further advanced.

  By the above, the soldering resist layer which consists of hardened | cured material of the photosensitive resin composition is provided on a core material. Thereby, a covering printed wiring board provided with a soldering resist layer is obtained.

  Hereinafter, the present invention will be specifically described by way of examples.

(1) Synthesis of carboxyl group-containing resin (Synthesis Example A-1 (i))
In a four-necked flask equipped with a reflux condenser, a thermometer, an air blowing tube and a stirrer, 203 parts by mass of a cresol novolac type epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., product number YDCN-700-5, epoxy equivalent 203), A mixture was prepared by adding 105 parts by mass of diethylene glycol monoethyl ether acetate, 0.2 part by mass of methylhydroquinone, 43.2 parts by mass of acrylic acid, and 3 parts by mass of triphenylphosphine. This mixture was heated under the conditions of a heating temperature of 100 ° C. and a heating time of 3 hours. Subsequently, after adding 68 parts by mass of tetrahydrophthalic acid, 0.3 parts by mass of methylhydroquinone and 65 parts by mass of diethylene glycol monoethyl ether acetate to the mixture, the mixture was heated under the conditions of a heating temperature of 110 ° C. and a heating time of 6 hours. Thereby, the epoxy equivalent is about 8300 g / eq. A 65 mass% solution of carboxyl group-containing fat (carboxyl group-containing resin solution A-1 (i)) was obtained.

(Synthesis Example A-1 (ii))
In a four-necked flask equipped with a reflux condenser, a thermometer, an air blowing tube and a stirrer, 288 parts by mass of a biphenyl novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., product number NC-3000-H, epoxy equivalent 288), A mixture was prepared by adding 155 parts by mass of diethylene glycol monoethyl ether acetate, 0.2 part by mass of methylhydroquinone, 36 parts by mass of acrylic acid, and 3 parts by mass of triphenylphosphine. This mixture was heated under the conditions of a heating temperature of 100 ° C. and a heating time of 3 hours. Subsequently, 85 parts by mass of tetrahydrophthalic acid, 0.3 part by mass of methylhydroquinone, and 40 parts by mass of diethylene glycol monoethyl ether acetate were added to the mixture, and then heated under the conditions of a heating temperature of 110 ° C. and a heating time of 10 hours. Thereafter, 27 parts by mass of diethylene glycol monoethyl ether acetate was added. Thereby, the epoxy equivalent is about 7800 g / eq. A 65 mass% solution of carboxyl group-containing resin (carboxyl group-containing resin solution A-1 (ii)) was obtained.

(Synthesis Example A-2 (i))
In a four-necked flask equipped with a reflux condenser, a thermometer, an air blowing tube, and a stirrer, 189 parts by mass of phenol novolac type epoxy resin (manufactured by DIC Corporation, product number EPICLON N-775, epoxy equivalent 189), diethylene glycol monoethyl A mixture was prepared by adding 103 parts by mass of ether acetate, 0.2 parts by mass of methylhydroquinone, 72 parts by mass of acrylic acid, and 1.5 parts by mass of triphenylphosphine. This mixture was heated under the conditions of a heating temperature of 115 ° C. and a heating time of 12 hours, thereby allowing the addition reaction to proceed. Subsequently, 60.8 parts by mass of tetrahydrophthalic anhydride and 71.5 parts by mass of diethylene glycol monoethyl ether acetate were added to the mixture, and the mixture was further heated under the conditions of a heating temperature of 90 ° C. and a heating time of 3 hours. This obtained the 65 mass% solution (carboxyl group containing resin solution A-2 (i)) of carboxyl group containing resin.

(Synthesis Example A-2 (ii))
In a four-necked flask equipped with a reflux condenser, a thermometer, an air blowing tube and a stirrer, 188 parts by mass of a phenol novolac type epoxy resin (manufactured by DIC Corporation, product number EPICLON N-770, epoxy equivalent 188), diethylene glycol monoethyl A mixture was prepared by adding 103 parts by mass of ether acetate, 0.2 parts by mass of methylhydroquinone, 72 parts by mass of acrylic acid, and 1.5 parts by mass of triphenylphosphine. This mixture was heated under the conditions of a heating temperature of 115 ° C. and a heating time of 12 hours, thereby allowing the addition reaction to proceed. Subsequently, 76 parts by mass of tetrahydrophthalic anhydride and 78.8 parts by mass of diethylene glycol monoethyl ether acetate were added to the mixture, and the mixture was further heated under the conditions of a heating temperature of 90 ° C. and a heating time of 3 hours. This obtained the 65 mass% solution (carboxyl group containing resin solution A-2 (ii)) of carboxyl group containing resin.

(Synthesis Example A-3 (i))
In a four-necked flask equipped with a reflux condenser, a thermometer, an air blowing tube and a stirrer, 203 parts by mass of a cresol novolac type epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., product number YDCN-700-5, epoxy equivalent 203), A mixture was prepared by adding 103 parts by mass of diethylene glycol monoethyl ether acetate, 0.2 parts by mass of methylhydroquinone, 72 parts by mass of acrylic acid, and 1.5 parts by mass of triphenylphosphine. This mixture was heated under the conditions of a heating temperature of 115 ° C. and a heating time of 12 hours, thereby allowing the addition reaction to proceed. Subsequently, 60.8 parts by mass of tetrahydrophthalic anhydride and 78.9 parts by mass of diethylene glycol monoethyl ether acetate were added to the mixture, and the mixture was further heated under the conditions of a heating temperature of 90 ° C. and a heating time of 3 hours. This obtained the 65 mass% solution (carboxyl group containing resin solution A-3 (i)) of carboxyl group containing resin.

(Synthesis Example A-3 (ii))
A four-necked flask equipped with a reflux condenser, a thermometer, an air blowing tube and a stirrer was charged with 472 parts by mass of a bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, product number jER1001, epoxy equivalent 472), diethylene glycol monoethyl ether acetate 202. A reaction solution was prepared by adding mass parts, 0.2 parts by mass of methylhydroquinone, 72 parts by mass of acrylic acid, and 3 parts by mass of triphenylphosphine. This reaction solution was heated at 115 ° C. for 12 hours while air was blown into the four-necked flask to cause the addition reaction to proceed. Subsequently, 118.9 parts by mass of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (Mitsubishi Gas Chemical Co., Ltd., product number H-TMAn-S) was added to the liquid in the four-necked flask, diethylene glycol. 158 mass parts of monoethyl ether acetate was added, and it was made to react by heating at 110 degreeC for 5 hours. This obtained the 65 mass% solution (carboxyl group containing resin solution A-3 (ii)) of carboxyl group containing resin.

(2) Preparation of photosensitive resin composition The components shown in the following table were kneaded with three rolls, and then stirred in the flask, whereby the photosensitivity of Examples 1 to 12 and Comparative Examples 1 to 7 was obtained. A resin composition was produced. Details of the components shown in the table are as follows.
Photopolymerization initiator B-1: 2,4,6-trimethylbenzoyldiphenylphosphine oxide, product number Irgacure TPO manufactured by BASF.
Photopolymerization initiator B-2: bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, product number Irgacure 819 manufactured by BASF.
Photopolymerization initiator B-3: 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, product number Irgacure 907 manufactured by BASF.
Photopolymerization initiator B-4: 1-hydroxy-cyclohexyl-phenyl-ketone, manufactured by BASF, product number Irgacure 184.
Photopolymerization initiator B-5: 2-hydroxy-2-methyl-4-phenyl-propan-1-one, product number Darocur 1173 manufactured by BASF.
Photopolymerization initiator B-6: 2,4-diethylthioxanthone, Nippon Kayaku Co., Ltd. product number Kayacure DETX-S.
Photopolymerization initiator B-7: 4,4′-bis (diethylamino) benzophenone, product number EAB manufactured by Hodogaya Chemical Co., Ltd.
Photopolymerization initiator B-8: Ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (0-acetyloxime), manufactured by BASF Part number Irgacure OXE02.
Photopolymerizable compound C: a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate, product number KAYARAD DPHA manufactured by Nippon Kayaku Co., Ltd.
Epoxy compound D-1 (crystalline): biphenyl type crystalline epoxy resin, product number YX-4000 manufactured by Mitsubishi Chemical Corporation.
Epoxy compound D-2 (crystalline): bisphenol type crystalline epoxy resin, product number YSLV-80XY manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.
Epoxy compound solution D-3: A solution obtained by dissolving amorphous cresol novolac type epoxy resin, product name EPICLON N-695 manufactured by DIC Corporation in diethylene glycol monoethyl ether acetate with a solid content of 70%.
Epoxy compound D-4: A phenol novolac type epoxy resin, manufactured by DIC Corporation, a product obtained by dissolving a reaction product of product number EPICLON N-775 and isophorone diisocyanate in diethylene glycol monoethyl ether acetate at a solid content of 75%.
Organic bentonite: Part No. Benton SD-2 manufactured by Leox Co.
Barium sulfate: Part number Variace B30 manufactured by Sakai Chemical Industry Co., Ltd.
-Talc: Part number SG2000 manufactured by Toshin Kasei Co., Ltd.
Melamine; product number melamine HM manufactured by Nissan Chemical Industries, Ltd.
Antifoaming agent: dimethicone (mixture of dimethicone and silicic acid), manufactured by Shin-Etsu Silicone Co., Ltd., product number KS-66.
Blue colorant: Pigment Blue 15: 3.
Yellow colorant: Pigment Yellow 147.
Organic solvent 1: Aromatic mixed solvent (petroleum naphtha).
Organic solvent 2: diethylene glycol monoethyl ether acetate.

(3) Preparation of test piece Using the photosensitive resin compositions of the examples and comparative examples, test pieces were prepared as follows.

  First, a copper foil was patterned by performing an etching process on a glass substrate epoxy resin copper-clad laminate having a copper foil having a thickness of 17.5 μm, thereby obtaining a printed wiring board.

  Then, the copper foil was roughened by melt | dissolving and removing the surface layer part about 1 micrometer thick in copper foil with the product number CZ-8101 by MEC Co., Ltd.

  A wet paint film was formed on the printed wiring board by applying the photosensitive resin compositions obtained in the respective Examples and Comparative Examples on the printed wiring board by a screen printing method. This wet coating film was preliminarily dried by heating under conditions of a heating temperature of 80 ° C. and a heating time of 20 minutes. This formed a 20-micrometer-thick film | membrane on copper foil.

A negative mask was directly applied onto the film, and the film was irradiated with ultraviolet rays of 250 mJ / cm ² through the negative mask. Thereby, the film was selectively exposed. Subsequently, the exposed film was subjected to a development treatment using an aqueous sodium carbonate solution, so that a portion (cured film) cured by the exposure of the film remained on the printed wiring board. The cured film was further heat-cured by heating at 150 ° C. for 60 minutes, and then irradiated with 1000 mJ / cm ² ultraviolet rays. Thus, a solder resist layer was formed on the printed wiring board, and a printed wiring board provided with this solder resist layer was used as a test piece.

(4) Evaluation test (4-1) Developability First, a copper foil is patterned by performing an etching process on a glass substrate epoxy resin copper clad laminate provided with a copper foil having a thickness of 17.5 μm, thereby a printed wiring board. Got.

  Then, the copper foil was roughened by melt | dissolving and removing the surface layer part about 1 micrometer thick in copper foil with the product number CZ-8101 by MEC Co., Ltd.

  A wet paint film was formed on the printed wiring board by applying the photosensitive resin compositions obtained in the respective Examples and Comparative Examples on the printed wiring board by a screen printing method. This wet coating film was preliminarily dried by heating under conditions of a heating temperature of 80 ° C. and a heating time of 20 minutes. This formed a 20-micrometer-thick film | membrane on copper foil. A sample was prepared by subjecting this film to development using an aqueous sodium carbonate solution.

  Moreover, the sample was produced by the same method except having changed the heating time at the time of preliminary drying into 80 minutes.

Samples were observed and evaluated as follows.
A: No film remained on the sample regardless of whether the heating time during the preliminary drying was 20 minutes or 80 minutes.
B: Although the film did not remain in the sample when the heating time during the preliminary drying was 20 minutes, a part of the film remained in the sample where the heating time during the preliminary drying was 80 minutes. It was.
C: A part of the film remained on the sample regardless of whether the heating time during the preliminary drying was 20 minutes or 80 minutes.

(4-2) Adhesiveness In accordance with the test method defined in JIS D0202, a cross-cut is made in a grid pattern in the solder resist layer of the test piece prepared in (3) above, followed by a peeling test using a cellophane adhesive tape. I did it. The state of peeling after the test was visually observed. The results were evaluated as follows.
A: No change is observed in all of the 100 crosscut portions.
B: Peeling occurred in 1 to 10 places out of 100 crosscut portions.
C: Peeling occurred at 11 to 100 of 100 cross cut portions.

(4-3) Pencil Hardness The pencil hardness of the solder resist layer of the test piece produced in the above (3) was measured using Mitsubishi High Uni (manufactured by Mitsubishi Pencil Co., Ltd.) as a pencil in accordance with JIS K5400.

(4-4) Acid resistance After immersing the test piece prepared in (3) above in a 10% aqueous sulfuric acid solution at room temperature for 30 minutes, the appearance of the solder resist layer of this test piece was observed. The results were evaluated as follows.
A: Abnormalities such as blistering, peeling, and discoloration are not observed in the solder resist layer.
B: Abnormalities such as blistering, peeling, and discoloration are slightly observed in the solder resist layer.
C: Abnormalities such as blistering, peeling, and discoloration are remarkably observed in the solder resist layer.

(4-5) Solder heat resistance 1
A water-soluble flux (product number LONCO 3355-11 manufactured by London Chemical Co., Ltd.) is applied to the solder resist layer of the test piece prepared in (3) above, and then the solder resist layer is immersed in a molten solder bath at 260 ° C. for 10 seconds. And then washed with water. After repeating this treatment three times, the appearance of the solder resist layer was observed, and the results were evaluated as follows.
A: Abnormalities such as blistering and peeling are not observed in the solder resist layer.
B: Abnormalities such as blistering and peeling are slightly observed in the solder resist layer.
C: Abnormalities such as blistering and peeling are remarkably observed in the solder resist layer.

(4-6) Solder heat resistance 2
A water-soluble flux (product number LONCO 3355-11 manufactured by London Chemical Co., Ltd.) is applied to the solder resist layer of the test piece prepared in (3) above, and then the solder resist layer is immersed in a molten solder bath at 260 ° C. for 10 seconds. And then washed with water. After repeating this treatment three times, the appearance of the solder resist layer was observed, and the results were evaluated as follows.
A: No whitening is observed in the solder resist layer.
B: Some whitening is seen in the solder resist layer.
C: Strong whitening is observed in the solder resist layer.

(4-7) Plating resistance 1
By performing electroless nickel plating and electroless gold plating sequentially on the test piece produced in (3) above using a commercially available plating solution, the cellophane adhesive tape peeling test of the solder resist layer of this test piece is performed. The adhesion state of the solder resist layer after plating was confirmed.

The results were evaluated as follows.
A: No peeling of the solder resist layer was observed in the cellophane adhesive tape peeling test.
B: Partial peeling of the solder resist layer is observed in the cellophane adhesive tape peeling test.
C: Large peeling of the solder resist layer is observed in the cellophane adhesive tape peeling test.

(4-8) Plating resistance 2
The test piece produced in the above (3) was subjected to electroless nickel plating and electroless gold plating sequentially using a commercially available plating solution, and then the state of the solder resist layer of this test piece was confirmed.

The results were evaluated as follows.
A: No whitening is observed in the solder resist layer.
B: Some whitening is seen in the solder resist layer.
C: Strong whitening is observed in the solder resist layer.

(4-9) PCT resistance After leaving the test piece produced by said (3) in saturated water vapor | steam of temperature 121 degreeC for 168 hours, the external appearance of the soldering resist layer of this test piece was observed. The results were evaluated as follows.
A: Abnormalities such as blistering, peeling, and discoloration are not observed in the solder resist layer.
B: Abnormalities such as blistering, peeling, and discoloration are slightly observed in the solder resist layer.
C: Abnormalities such as blistering, peeling, and discoloration are remarkably observed in the solder resist layer.

(4-10) Electrical insulation A printed wiring board for evaluation was obtained by forming a comb-shaped electrode having a line width / space width of 50 μm / 50 μm on an FR-4 type copper-clad laminate. A solder resist layer was formed on this printed wiring board under the same production method and conditions as in (3) above. Subsequently, while applying a bias voltage of DC 12 V to the comb-shaped electrode, the printed wiring board was placed at 121 ° C. and 97% R.D. H. The test environment was exposed for 150 hours. The electrical resistance value of the solder resist layer in this test environment was constantly measured. The results were evaluated according to the following evaluation criteria.
A: The electric resistance value was always 10 ⁶ Ω or more from the start of the test until 150 hours passed.
B: The electric resistance value was 10 ⁶ Ω or more until at least 100 hours passed from the start of the test, but the electric resistance value was less than 10 ⁶ Ω until 150 hours passed.
C: The electric resistance value was less than 10 ⁶ Ω before 100 hours passed from the start of the test.

  The results of the above evaluation tests are shown in Table 1 and Table 2 below.

Claims (6)

A carboxyl group-containing resin (A);
A photopolymerization initiator (B);
A photopolymerizable compound (C);
An epoxy compound (D),
The carboxyl group-containing resin (A) contains a carboxyl group-containing resin (A-1) and a carboxyl group-containing resin (A-2),
The carboxyl group-containing resin (A-1) is a reaction product of an epoxy resin (a11) having a novolak structure, an unsaturated carboxylic acid (a12) and a polybasic acid (a13),
The carboxyl group-containing resin (A-2) includes an intermediate that is a reaction product of an epoxy resin (a21) having a phenol novolak structure and an unsaturated carboxylic acid (a22), and a polybasic acid anhydride (a23). A reactant,
Photosensitive resin composition. The unsaturated carboxylic acid (a12) is in the range of 0.2 to 0.8 mol with respect to 1 mol of the epoxy group of the epoxy resin (a11),
The polybasic acid (a13) is in the range of 0.2 to 0.8 mol with respect to 1 mol of the epoxy group of the epoxy resin (a11).
The photosensitive resin composition according to claim 1. The unsaturated carboxylic acid (a22) is in the range of 0.8 to 1.2 mol with respect to 1 mol of the epoxy group of the epoxy resin (a21),
The polybasic acid anhydride (a23) is in the range of 0.2 to 0.8 mol with respect to 1 mol of the epoxy group of the epoxy resin (a21).
The photosensitive resin composition according to claim 1. The photopolymerization initiator (B) contains an acylphosphine oxide photopolymerization initiator.
The photosensitive resin composition as described in any one of Claim 1 to 3. The epoxy compound (D) contains a crystalline epoxy resin,
The photosensitive resin composition as described in any one of Claim 1 to 4. A coated printed wiring board comprising a solder resist layer that is a cured product of the photosensitive resin composition according to any one of claims 1 to 5.