TWI853086B - Photosensitive resin composition, dry film having photosensitive resin composition, and printed circuit board having photocured product of photosensitive resin composition - Google Patents

Abstract

The purpose of the present invention is to provide a photosensitive resin composition that can form a photocurable film without damaging the high sensitivity to ultraviolet rays and having excellent alkali developability, plating property, etc. The photosensitive resin composition of the present invention is a photosensitive resin composition containing (A) a carboxyl group-containing photosensitive resin, (B) an antioxidant, (C) a photopolymerization initiator, (D) a reactive diluent, and (E) an epoxy compound, wherein the aforementioned (B) antioxidant contains at least one compound selected from the group consisting of (B1) a compound having a phenolic hydroxyl group and phosphorus and (B2) a compound having a phenolic hydroxyl group and sulfur.

Description

Photosensitive resin composition, dry film having photosensitive resin composition, and printed circuit board having photocured photosensitive resin composition

The present invention relates to a coating material, such as a photosensitive resin composition suitable for an insulating coating material, a dry film having a coating film in which the photosensitive resin composition is coated on a film, and a printed circuit board coated with a photocurable material in which the photosensitive resin composition is photocured.

A conductor circuit diagram of a conductor (e.g., copper foil) is formed on a substrate, and electronic components are mounted by soldering on the soldering land of the circuit diagram. The circuit portion other than the soldering land is covered with a solder resist film as an insulating film serving as a protective film. As the insulating film, a photocurable film of a photosensitive resin composition including a photosensitive resin containing a carboxyl group and a photopolymerization initiator is used. In addition, an antioxidant may be added to the photosensitive resin composition in order to achieve the purpose of preventing yellowing of the photocurable film, preventing halo during the photocuring reaction, stabilizing the shape of the through-port portion, and the like.

Among them, when it is desired to prevent yellowing of a photocurable film and halo during a photocuring reaction, a photosensitive resin composition to which an antioxidant is added is proposed, for example, a photosensitive resin composition containing (A) a carboxyl group-containing photosensitive resin, (B) a phenolic compound, (C) an organic sulfur compound, (D) a photopolymerization initiator, (E) a diluent, (F) an epoxy compound, and (G) a colorant (Patent Document 1). Patent Document 1 states that by adding (B) a phenolic compound and (C) an organic sulfur compound as an antioxidant, yellowing of a photocurable film and halo during a photocuring reaction can be prevented.

On the other hand, from the viewpoint of miniaturization of electronic components mounted on printed circuit boards and mounting of electronic components at high density, solder resist films are required to have high resolution. In order to improve the resolution of the soldering resist film, a photosensitive resin composition that is highly sensitive to ultraviolet rays is required. When it is desired to increase the sensitivity of the photosensitive resin composition, an oxime ester-based photopolymerization initiator may be used as the photopolymerization initiator.

However, when an oxime ester-based photopolymerization initiator is used, the sensitivity of the photosensitive resin composition will be too high. Even if an antioxidant such as a phenolic compound or an organic sulfur compound is added, the halo cannot be fully suppressed. For example, the small-diameter opening cannot be imaged. There is still room for improvement in the alkali developability.

Furthermore, in a case where the influence of oxygen barrier is relatively small (for example, a state where a resin film such as PET is laminated on a coating film of a photosensitive resin composition), when the photosensitive resin composition is photocured, if an oxime ester-based photopolymerization initiator is used, the UV rays may scan an inappropriate coating area, so that the photocuring reaction of the coating film may be excessively advanced, and defects such as scum may be generated in the photocured film. When defects such as scum are generated in the photocured film, for example, when a photocured film of a photosensitive resin composition formed on a conductor is subjected to a plating treatment such as gold plating, unevenness may occur in the plated film such as the gold plated film, and the plated film may not be attached. Therefore, there is still room for improvement in the plating properties of conventional photosensitive resin compositions to which antioxidants such as phenolic compounds or organic sulfur compounds are added. [Prior art literature] [Patent literature]

[Patent Document 1] Japanese Patent Application Publication No. 2011-70108

[Problem solved by the invention]

In view of the above, the purpose of the present invention is to provide a photosensitive resin composition that can form a high sensitivity to ultraviolet rays without damaging it and has excellent coating properties such as alkali developability and gold plating properties. [Means for solving the problem]

The gist of the present invention is as follows. [1] A photosensitive resin composition comprising (A) a carboxyl group-containing photosensitive resin, (B) an antioxidant, (C) a photopolymerization initiator, (D) a reactive diluent, and (E) an epoxy compound, wherein the antioxidant (B) comprises at least one compound selected from the group consisting of (B1) a compound having a phenolic hydroxyl group and phosphorus and (B2) a compound having a phenolic hydroxyl group and sulfur. [2] The photosensitive resin composition described in [1] wherein the antioxidant (B) comprises the compound (B1) having a phenolic hydroxyl group and phosphorus. [3] The photosensitive resin composition described in [1] or [2] contains 0.40 parts by mass to 12.0 parts by mass of the antioxidant (B) per 100 parts by mass of the photosensitive resin (A) containing a carboxyl group. [4] The photosensitive resin composition described in [2] contains 2.0 parts by mass to 6.0 parts by mass of the compound (B1) having a phenolic hydroxyl group and phosphorus per 100 parts by mass of the photosensitive resin (A) containing a carboxyl group. [5] The aforementioned (B) antioxidant contains the aforementioned (B2) compound having a phenolic hydroxyl group and sulfur, and the photosensitive resin composition described in any one of [1] to [4] contains 0.50 mass parts to 1.5 mass parts of the aforementioned (B2) compound having a phenolic hydroxyl group and sulfur per 100 mass parts of the aforementioned (A) photosensitive resin containing a carboxyl group. [6] The aforementioned (B1) compound having a phenolic hydroxyl group and phosphorus is the following formula (1): [7] The compound (B2) having a phenolic hydroxyl group and sulfur is the following formula (2): [8] A photosensitive resin composition described in any one of [1] to [7], wherein the aforementioned (C) photopolymerization initiator contains an oxime ester-based photopolymerization initiator. [9] A photocured product of the photosensitive resin composition described in any one of [1] to [8]. [10] A dry film comprising the photosensitive resin composition described in any one of [1] to [8]. [11] A printed circuit board comprising the photocured product of the photosensitive resin composition described in any one of [1] to [8]. [Effects of the Invention]

According to the aspect of the present invention, by containing (B) an antioxidant at least one compound selected from the group consisting of (B1) a compound having a phenolic hydroxyl group and phosphorus and (B2) a compound having a phenolic hydroxyl group and sulfur, a photosensitive resin composition can be obtained that forms a photocurable film that does not impair high sensitivity to ultraviolet rays and has excellent plating properties such as gold plating properties. In addition, according to the aspect of the present invention, by containing (B) an antioxidant at least one compound selected from the group consisting of (B1) a compound having a phenolic hydroxyl group and phosphorus and (B2) a compound having a phenolic hydroxyl group and sulfur, excellent alkali developing properties can be obtained, so that the non-exposed portion of the coating of the photosensitive resin composition can be reliably subjected to alkali development, and the coating can be reliably removed at the small-diameter opening by alkali development.

According to the aspect of the present invention, by containing (B1) a compound having a phenolic hydroxyl group and phosphorus as the antioxidant, the alkali developability can be further improved, and the non-exposed portion of the coating film of the photosensitive resin composition can be more reliably subjected to alkali development.

According to the aspect of the present invention, by containing 0.40 to 12.0 parts by mass of (B) antioxidant per 100 parts by mass of (A) carboxyl group-containing photosensitive resin, the sensitivity to ultraviolet rays can be reliably improved, and the plating properties such as alkali developability and gold plating properties can be further improved.

According to the present invention, by containing 2.0 parts by mass to 6.0 parts by mass of a compound having a phenolic hydroxyl group and phosphorus (B1) per 100 parts by mass of the photosensitive resin having a carboxyl group, the balance of plating properties such as sensitivity and plating properties can be further improved.

According to the aspect of the present invention, when the (B) antioxidant contains the (B2) compound having a phenolic hydroxyl group and sulfur, the (B2) compound having a phenolic hydroxyl group and sulfur is contained in an amount of 0.50 parts by mass to 1.5 parts by mass based on 100 parts by mass of the (A) photosensitive resin having a carboxyl group, the balance of plating properties such as alkali developability and plating properties can be further improved.

[Type of implementation of the invention]

Next, the photosensitive resin composition of the present invention is described as follows. The photosensitive resin composition of the present invention is a photosensitive resin composition containing (A) a carboxyl group-containing photosensitive resin, (B) an antioxidant, (C) a photopolymerization initiator, (D) a reactive diluent, and (E) an epoxy compound, wherein the antioxidant (B) contains at least one compound selected from the group consisting of (B1) a compound having a phenolic hydroxyl group and phosphorus and (B2) a compound having a phenolic hydroxyl group and sulfur.

(A) Photosensitive resin containing carboxyl groups The chemical structure of the photosensitive resin containing carboxyl groups of the component (A) is not particularly limited, and examples thereof include resins having one or more photosensitive unsaturated double bonds and free carboxyl groups. Examples of the aforementioned photosensitive resin containing a carboxyl group include free radical polymerizable unsaturated monocarboxylic acid epoxy resins such as epoxy (meth) acrylate obtained by reacting free radical polymerizable unsaturated monocarboxylic acid such as acrylic acid or methacrylic acid (hereinafter sometimes referred to as "(meth) acrylic acid") on at least a part of the epoxy groups of a multifunctional epoxy resin having two or more epoxy groups in one molecule, and polyacid-modified free radical polymerizable unsaturated monocarboxylic acid epoxy resins such as polyacid-modified epoxy (meth) acrylate obtained by reacting the generated hydroxyl group with a polyacid and/or a polyacid anhydride.

If the polyfunctional epoxy resin is a bifunctional or higher functional epoxy resin, the chemical structure is not particularly limited. In addition, the epoxy equivalent of the polyfunctional epoxy resin is not particularly limited. For example, the upper limit of the epoxy equivalent is preferably 3000 g/eq, more preferably 2000 g/eq, and particularly preferably 1500 g/eq. On the other hand, the lower limit of the epoxy equivalent is preferably 100 g/eq, and particularly preferably 200 g/eq.

Examples of the polyfunctional epoxy resin include bisphenol A epoxy resin, bisphenol F epoxy resin and other phenol novolac epoxy resins, biphenyl aralkyl epoxy resins, phenyl aralkyl epoxy resins, biphenyl epoxy resins, naphthalene epoxy resins, dicyclopentadiene epoxy resins, silicone-modified epoxy resins and other rubber-modified epoxy resins, ε-caprolactone-modified epoxy resins, and the like. Resins, o-cresol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, epoxies, glycidyl ester type multifunctional epoxy resins, glycidyl amine type multifunctional epoxy resins, heterocyclic multifunctional epoxy resins, bisphenol modified novolac type epoxy resins, multifunctional modified novolac type epoxy resins, etc. In addition, these epoxy resins may be used in which halogen atoms such as Br and Cl are further introduced. These multifunctional epoxy resins may be used alone or in combination of two or more.

The free radical polymerizable unsaturated monocarboxylic acid is not particularly limited, and examples thereof include (meth)acrylic acid, crotonic acid, chamomile acid, angelic acid, cinnamic acid, etc. Among these, (meth)acrylic acid is preferred from the viewpoint of availability and handling properties. These free radical polymerizable unsaturated monocarboxylic acids may be used alone or in combination of two or more.

The method for reacting the polyfunctional epoxy resin with the radical polymerizable unsaturated monocarboxylic acid is not particularly limited. For example, there can be mentioned a method in which the polyfunctional epoxy resin and the radical polymerizable unsaturated monocarboxylic acid are dissolved in a non-reactive diluent such as an organic solvent and then heated.

The polyacid and/or polyacid anhydride is obtained by introducing free carboxyl groups into the free radical polymerizable unsaturated monocarboxylic acid epoxy resin after an addition reaction on the hydroxyl groups generated by the reaction of a polyfunctional epoxy resin and a free radical polymerizable unsaturated monocarboxylic acid. The chemical structures of the polyacid and polyacid anhydride are not particularly limited, and any unsaturated monocarboxylic acid can be used. Examples of the polyacid include succinic acid, maleic acid, adipic acid, citric acid, phthalic acid, tetrahydrophthalic acid, tetrahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, 3-ethyltetrahydrophthalic acid, 4-ethyltetrahydrophthalic acid, and other tetrahydrophthalic acids, hexahydrophthalic acid, 3-methylhexahydrophthalic acid, and 4-ethyltetrahydrophthalic acid. Hexahydrophthalic acid such as hydrophthalic acid, 4-methylhexahydrophthalic acid, 3-ethylhexahydrophthalic acid, 4-ethylhexahydrophthalic acid, tetrahydrophthalic acid such as methyltetrahydrophthalic acid, terminal methylene tetrahydrophthalic acid, methylterminated methylene tetrahydrophthalic acid, trimellitic acid, pyromellitic acid, and diglycolic acid. As the polybasic acid anhydride, the above-mentioned various polybasic acid anhydrides (acid anhydrides) can be cited. These compounds can be used alone or in combination of two or more.

The method for reacting the free radical polymerizable unsaturated monocarboxylic acid epoxy resin with the polyacid and/or polyacid anhydride is not particularly limited. For example, there can be cited a method in which the free radical polymerizable unsaturated monocarboxylic acid epoxy resin and the polyacid and/or polyacid anhydride are dissolved in a non-reactive diluent such as an organic solvent and then heated.

The polyacid-modified unsaturated monocarboxylic acid epoxy resin can be used as a photosensitive resin containing a carboxyl group. In addition, a polyacid-modified free radical polymerizable unsaturated monocarboxylic acid epoxy resin to which a free radical polymerizable unsaturated group is added by addition reaction of a compound having an epoxy group with one or more free radical polymerizable unsaturated groups to a part of the carboxyl groups of the polyacid-modified unsaturated monocarboxylic acid epoxy resin obtained as above can be used as a photosensitive resin containing a carboxyl group. The polyacid-modified free radical polymerizable unsaturated monocarboxylate epoxy resin to which free radical polymerizable unsaturated groups are further added has a chemical structure in which free radical polymerizable unsaturated groups are further introduced into the side chain of the polyacid-modified unsaturated monocarboxylate epoxy resin. Therefore, it is a photosensitive resin containing a carboxyl group with a higher photosensitivity than the polyacid-modified unsaturated monocarboxylate epoxy resin.

Examples of compounds having one or more free radical polymerizable unsaturated groups and epoxy groups include glycidyl compounds. Examples of glycidyl compounds include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, pentaerythritol triacrylate monoglycidyl ether, pentaerythritol trimethacrylate monoglycidyl ether, and the like. The glycidyl compound may have one or more glycidyl groups in one molecule. Furthermore, compounds having one or more free radical polymerizable unsaturated groups and epoxy groups may be used alone or in combination of two or more.

The method for reacting the polyacid-modified unsaturated monocarboxylic acid epoxy resin with a compound having one or more free radical polymerizable unsaturated groups and epoxy groups such as a glyceryl compound is not particularly limited. For example, there can be mentioned a method in which the polyacid-modified unsaturated monocarboxylic acid epoxy resin and a compound having one or more free radical polymerizable unsaturated groups and epoxy groups are dissolved in a non-reactive diluent such as an organic solvent and then heated.

The acid value of the photosensitive resin containing a carboxyl group is not particularly limited, but the lower limit is preferably 30 mgKOH/g, and particularly preferably 40 mgKOH/g, from the viewpoint of alkaline development. On the other hand, the upper limit of the acid value of the photosensitive resin containing a carboxyl group is preferably 200 mgKOH/g, from the viewpoint of preventing the dissolution of the exposed portion by an alkaline developer, and particularly preferably 150 mgKOH/g, from the viewpoint of reliably preventing the moisture resistance and insulation reliability of the photocured product from being reduced.

The mass average molecular weight of the photosensitive resin containing a carboxyl group is not particularly limited. For example, the lower limit is preferably 6,000, more preferably 7,000, and particularly preferably 8,000 from the viewpoint of the toughness and touch drying of the photocured product. On the other hand, the upper limit of the mass average molecular weight of the photosensitive resin containing a carboxyl group is preferably 200,000, more preferably 100,000, and particularly preferably 50,000 from the viewpoint of development with alkali. The so-called "mass average molecular weight" means the mass average molecular weight calculated in terms of polystyrene by gel permeation chromatography (GPC) at room temperature.

The photosensitive resin containing a carboxyl group can be prepared by using the above-mentioned components in the above-mentioned reaction steps, or a commercially available photosensitive resin containing a carboxyl group can be used. Examples of commercially available photosensitive resins containing a carboxyl group include "KAYARAD ZAR-2000", "KAYARAD ZFR-1122", "KAYARAD FLX-2089", "KAYARAD ZCR-1569H" (all from Nippon Kayaku Co., Ltd.), "Cyclomer P (ACA) Z-250" (Daicel Ornex Co., Ltd.), and "SP-4621" (Showa Denko Co., Ltd.). In addition, these photosensitive resins containing a carboxyl group can be used alone or in combination of two or more.

(B) Antioxidant As the antioxidant of component (B), at least one compound selected from the group consisting of (B1) a compound having a phenolic hydroxyl group and phosphorus and (B2) a compound having a phenolic hydroxyl group and sulfur is used. By using at least one compound selected from the group consisting of (B1) a compound having a phenolic hydroxyl group and phosphorus and (B2) a compound having a phenolic hydroxyl group and sulfur as the antioxidant of the component (B), a photosensitive resin composition can be obtained which can form a photocurable film having high sensitivity to active energy rays such as ultraviolet rays and excellent plating properties such as gold plating properties without impairing the photosensitive resin composition. In addition, since excellent alkaline developing properties that can fully prevent halation can be obtained, the non-exposed parts of the coating of the photosensitive resin composition can be reliably removed by alkaline development. For example, the coating can be reliably removed by alkaline development even at a small-diameter via or a fine pad.

Examples of the compound having a phenolic hydroxyl group and phosphorus as the component (B1) include compounds having a phenolic hydroxyl group and a phosphite structure represented by P(OR ¹ )(OR ² )(OR ³ )(R ¹ , R ² , and R ³ are organic groups) in the skeleton. Examples of the compound having a phenolic hydroxyl group and a phosphite structure represented by P(OR ¹ )(OR ² )(OR ³ ) in the skeleton include compounds represented by the following formula (1).

In addition, the butyl group of the above formula (1) may be replaced by a compound having hydrogen, an alkyl group having 1 to 3 carbon atoms, a phenolic hydroxyl group of an alkyl group having 5 to 10 carbon atoms, and phosphorus, and the methyl group of the above formula (1) may be replaced by a compound having hydrogen, an alkyl group having 2 to 10 carbon atoms, and phosphorus. Examples of the compound represented by the above formula (1) include "Sumilizer GP" (Sumitomo Chemical Co., Ltd.).

Examples of the compound having a phenolic hydroxyl group and sulfur as component (B2) include compounds in which phenol is substituted with a substituent of -R ⁴ -SR ⁵ (wherein R ⁴ represents a hydrocarbon having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and R ⁵ represents a hydrocarbon having 5 to 20 carbon atoms, preferably 10 to 15 carbon atoms). The number of the substituent -R ⁴ -SR ⁵ is at least 1, preferably 2.

Examples of the compound in which phenol is substituted with -R ⁴ -SR ⁵ include the compound represented by the following formula (2).

As the compound represented by the above formula (2), " Irganox 1726" (BASF Corporation) can be cited.

In the photosensitive resin composition of the present invention, a compound having a phenolic hydroxyl group and phosphorus and a compound having a phenolic hydroxyl group and sulfur can be used in combination, or either a compound having a phenolic hydroxyl group and phosphorus or a compound having a phenolic hydroxyl group and sulfur can be used. Among them, a compound having a phenolic hydroxyl group and phosphorus is preferred from the viewpoint of further improving the alkali developing property and making it possible to more reliably remove the non-exposed part of the coating film of the photosensitive resin composition by alkali development.

The amount of at least one compound selected from the group consisting of a compound having a phenolic hydroxyl group and phosphorus, and a compound having a phenolic hydroxyl group and sulfur is not particularly limited, but the lower limit is preferably 0.40 parts by mass, more preferably 0.50 parts by mass, more preferably 1.0 parts by mass, and particularly preferably 2.0 parts by mass, based on 100 parts by mass of the photosensitive resin containing a carboxyl group (solid content, the same below), from the viewpoint of further improving the plating properties such as gold plating properties. On the other hand, the upper limit of the amount of at least one compound selected from the group consisting of a compound having a phenolic hydroxyl group and phosphorus, and a compound having a phenolic hydroxyl group and sulfur is preferably 12.0 parts by mass, more preferably 10.0 parts by mass, and particularly preferably 5.0 parts by mass based on 100 parts by mass of the photosensitive resin containing a carboxyl group, from the viewpoint of reliably improving the sensitivity to ultraviolet rays and obtaining excellent alkali developability.

Furthermore, when the compound having a phenolic hydroxyl group and phosphorus is added but the compound having a phenolic hydroxyl group and sulfur is not added, the lower limit of the amount of the compound having a phenolic hydroxyl group and phosphorus is preferably 1.0 part by mass, more preferably 1.5 parts by mass, and particularly preferably 2.0 parts by mass based on 100 parts by mass of the photosensitive resin containing a carboxyl group, from the viewpoint of further improving the plating properties such as gold plating properties. On the other hand, when the compound having a phenolic hydroxyl group and phosphorus is added but the compound having a phenolic hydroxyl group and sulfur is not added, the upper limit of the amount of the compound having a phenolic hydroxyl group and phosphorus is preferably 10.0 parts by mass, more preferably 7.5 parts by mass, more preferably 6.0 parts by mass, and particularly preferably 5.0 parts by mass based on 100 parts by mass of the photosensitive resin containing a carboxyl group from the viewpoint of further improving sensitivity.

Furthermore, when a compound having a phenolic hydroxyl group and sulfur is added but a compound having a phenolic hydroxyl group and phosphorus is not added, the lower limit of the compound having a phenolic hydroxyl group and sulfur is preferably 0.50 parts by mass, and particularly preferably 0.75 parts by mass, based on 100 parts by mass of the photosensitive resin containing a carboxyl group, from the viewpoint of further improving plating properties such as gold plating properties. On the other hand, when a compound having a phenolic hydroxyl group and sulfur is added but a compound having a phenolic hydroxyl group and phosphorus is not added, the upper limit of the compound having a phenolic hydroxyl group and sulfur is preferably 2.5 parts by mass, more preferably 2.0 parts by mass, and particularly preferably 1.5 parts by mass, based on 100 parts by mass of the photosensitive resin containing a carboxyl group, from the viewpoint of further improving alkali developing properties.

Furthermore, as the (B) antioxidant, if necessary, (B1) a compound having a phenolic hydroxyl group and phosphorus and/or (B2) a compound having a phenolic hydroxyl group and sulfur, and an antioxidant other than the (B1) component and the (B2) component (hereinafter sometimes referred to as "other antioxidants") may be used in combination. Examples of other antioxidants that may be used in combination include phenolic antioxidants that do not contain phosphorus and do not contain sulfur (hereinafter sometimes referred to as "phenolic antioxidants"), phosphorus antioxidants that do not have a phenolic hydroxyl group (hereinafter sometimes referred to as "phosphorus antioxidants"), and sulfur antioxidants that do not have a phenolic hydroxyl group (hereinafter sometimes referred to as "sulfur antioxidants"), etc.

Examples of phenolic antioxidants include 3,9-bis{2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxahertzspiro[5,5]undecane, 3,9-bis{2-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxahertzspiro[5,5]undecane, 3,9-bis{2-[3-(3-iso-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1'-dimethyl Hindered phenol antioxidants include 2,4,8,10-tetraoxaspiro[5,5]undecane, 3,9-bis{2-[3-(4-hydroxy-5-methylphenyl)propionyloxy]1,1'-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, 3,9-bis{2-[3-(3-t-butyl-5-ethyl-4-hydroxyphenyl)propionyloxy]1,1'-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, and 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate stearyl. Examples of hindered phenol antioxidants on the market include "Irganox 1010" (BASF).

As a phosphorus-based antioxidant, for example, 2,4-di-tert-butylphenyl phosphite, which is already on the market as "Irgafos 168" (BASF), can be cited.

Examples of the sulfur-based antioxidant include organic sulfur-based compounds represented by the following general formula (I). (In formula (I), R ⁶ represents an alkyl group having 10 to 20 carbon atoms, and the four R ⁶ groups may be the same or different) Examples of the alkyl group having 10 to 20 carbon atoms for R ⁶ include lauryl, myristyl, palmityl, and stearyl. Examples of commercially available sulfur-based antioxidants include "Sumilizer TP-D" (Sumitomo Chemical Co., Ltd.).

The amount of other antioxidants to be added is not particularly limited, but the lower limit is preferably 0.05 parts by mass, and particularly preferably 0.10 parts by mass, based on 100 parts by mass of the photosensitive resin containing a carboxyl group, from the viewpoint of reliably providing halo suppression. On the other hand, the upper limit of the amount of other antioxidants to be added is preferably 2.0 parts by mass, and particularly preferably 1.0 parts by mass, based on 100 parts by mass of the photosensitive resin containing a carboxyl group, from the viewpoint of reliably maintaining high sensitivity.

(C) Photopolymerization initiator The photopolymerization initiator of component (C) is not particularly limited, and any type can be used. Examples of the photopolymerization initiator include 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyl oxime)], acetone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-, 1-(O-acetyl oxime), 2-(acetyloxyiminomethyl)thiazol-9-one, 1,8-octanedione, 1,8-bis[9-ethyl-6-nitro-9H-carbazole-3 Oxime ester photopolymerization initiators include oxime esters such as ((1-methoxypropane-2-yl)oxy)-2-methylphenyl)methanone O-acetyl oxime, (((1-methoxypropane-2-yl)oxy)-2-methylphenyl)methanone)-1,8-bis(O-acetyl oxime), (((1-methoxypropane-2-yl)oxy)-2-methylphenyl)methanone)-1,8-bis(O-acetyl oxime), (((1-methoxypropane-2-yl)oxy)-2-methylphenyl)methanone)-1,8-bis(O-acetyl oxime). These compounds may be used alone or in combination of two or more. Oxime ester photopolymerization initiators can impart high sensitivity to active energy rays such as ultraviolet rays to photosensitive resin compositions.

In the present invention, even if an oxime ester-based photopolymerization initiator is added, the (B) antioxidant contains at least one compound selected from the group consisting of (B1) a compound having a phenolic hydroxyl group and phosphorus and (B2) a compound having a phenolic hydroxyl group and sulfur. Therefore, halation during the photocuring reaction can be prevented, thereby forming a photocurable film with excellent alkali developability, gold plating property, and other plating properties.

In addition, when a photopolymerization initiator other than an oxime ester-based photopolymerization initiator is used, for example, phenylbis(2,4,6-trimethylbenzyl)phosphine oxide, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1-benzyl-1-(dimethylamino)propyl-4-morpholinophenyl-ketone, 2-methyl-4′-(methylthio)-2-morpholinopropiophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) -Butanone-1, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexyl phenyl ketone, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4'-bis(diethylamino)benzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothiazolone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ethyl ester, and the like. These compounds may be used alone or in combination of two or more.

The content of the photopolymerization initiator is not particularly limited, but is preferably 0.10 to 10 parts by mass, and particularly preferably 0.50 to 5.0 parts by mass, based on 100 parts by mass of the photosensitive resin containing a carboxyl group.

(D) Reactive diluent The reactive diluent of the component (D) is, for example, a photopolymerizable monomer, a compound having at least one, preferably two or more, polymerizable double bonds per molecule. The reactive diluent can fully photoharden the photosensitive resin composition, thereby improving the acid resistance, heat resistance, alkali resistance, etc. of the photohardened material.

Examples of the reactive diluent include monofunctional (meth)acrylate monomers and bifunctional or higher functional (meth)acrylate monomers. Examples of the monofunctional (meth)acrylate monomer include 2-hydroxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, diethylene glycol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, and caprolactone-modified (meth)acrylate. Examples of the (meth)acrylate monomer having two or more functional groups include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, dicyclopentyl di(meth)acrylate, ethylene oxide modified phosphate di(meth)acrylate, and allyl cyclohexyl di(meth)acrylate. Acrylate, isocyanurate di(meth)acrylate, trihydroxymethylpropane tri(meth)acrylate, ditrihydroxymethylpropane tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trihydroxymethylpropane tri(meth)acrylate, tris(acryloyloxyethyl) isocyanurate, propionic acid modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, urethane (meth)acrylate, etc. These compounds may be used alone or in combination of two or more.

The amount of the reactive diluent to be added is not particularly limited, but is preferably 5.0 to 100 parts by mass, and particularly preferably 10 to 30 parts by mass, based on 100 parts by mass of the photosensitive resin containing a carboxyl group.

(E) Epoxy compound The epoxy compound of the component (E) is used to increase the crosslinking density of the photocured product of the photosensitive resin composition to obtain a photocured film having sufficient mechanical strength. Examples of the epoxy compound include epoxy resins. Examples of the epoxy resins include biphenyl type epoxy resins, biphenyl aralkyl type epoxy resins, bisphenol A type epoxy resins, tetramethyl bisphenol F type epoxy resins, bisphenol F type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, dicyclopentadiene type epoxy resins, and adamantane type epoxy resins. Among these, bisphenol A type epoxy resin, biphenyl type epoxy resin, and tetramethyl bisphenol F type epoxy resin are preferred from the viewpoint of further improving the pot life, and biphenyl type epoxy resin and tetramethyl bisphenol F type epoxy resin are particularly preferred. These compounds may be used alone or in combination of two or more.

The amount of the epoxy compound to be added is not particularly limited, but is preferably 5.0 to 100 parts by mass, and particularly preferably 10 to 50 parts by mass, based on 100 parts by mass of the carboxyl group-containing photosensitive resin, from the viewpoint of reliably obtaining a photocured product having sufficient mechanical strength.

In the photosensitive resin composition of the present invention, in addition to the above-mentioned components (A) to (E), other components may be added as necessary, for example, physical pigments, flame retardants, hardening accelerators, additives, colorants, non-reactive diluents, etc. may be appropriately added.

Examples of the physical pigment include talc, barium sulfate, hydrophobic silica, aluminum oxide, aluminum hydroxide, mica, etc. The flame retardant is used to impart flame retardancy to the photocured product of the photosensitive resin composition of the present invention, and examples thereof include phosphorus-based flame retardants. Examples of phosphorus-based flame retardants include halogen-containing phosphates such as quinoline (chloroethyl) phosphate, quinoline (2,3-dichloropropyl) phosphate, quinoline (2-chloropropyl) phosphate, quinoline (2,3-bromopropyl) phosphate, quinoline (bromochloropropyl) phosphate, 2,3-dibromopropyl-2,3-chloropropyl phosphate, quinoline (tribromophenyl) phosphate, quinoline (dibromophenyl) phosphate, and quinoline (tribromoneopentyl) phosphate; trimethyl phosphate; , triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate and other non-halogen aliphatic phosphates; triphenyl phosphate, cresol diphenyl phosphate, dicresol phenyl phosphate, tricresol phosphate, trixyl phosphate, ditolyl diphenyl phosphate, phenyl (isopropyl phenyl) phosphate, isopropyl phenyl diphenyl phosphate, diisopropyl phenyl phosphate, phenyl (trimethyl phenyl) phosphate, phenyl ( Non-halogen aromatic phosphates such as t-butylphenyl) phosphate, hydroxyphenyl diphenyl phosphate, octyl diphenyl phosphate, etc.; phosphonic acids such as aluminum tris-diethylphosphonate, aluminum tris-methylethylphosphonate, aluminum tris-diphenylphosphonate, zinc bis-diethylphosphonate, zinc bis-methylethylphosphonate, zinc bis-diphenylphosphonate, titanium bis-diethylphosphonate, titanium tetrakis-diethylphosphonate, titanium bis-methylethylphosphonate, titanium tetrakis-methylethylphosphonate, titanium bis-diphenylphosphonate, titanium tetrakis-diphenylphosphonate, etc. Metal salts of 9,10-dihydro-9-oxa-10-phosphophananthrene-10-oxide (hereinafter referred to as HCA), HCA modified compounds such as addition reaction products of HCA and acrylate, addition reaction products of HCA and epoxy resin, addition reaction products of HCA and hydroquinone, phosphine oxide compounds such as diphenylvinylphosphine oxide, triphenylphosphine oxide, trialkylphosphine oxide, tris(hydroxyalkyl)phosphine oxide, etc. Among them, organic phosphate flame retardants are preferred.

Examples of curing accelerators include benzoxazole and its derivatives, dicyandiamide (DICY) and its derivatives, melamine and its derivatives, boron trifluoride-amine complex, organic acid hydrazide, diaminomaleonitrile (DAMN) and its derivatives, guanamine and its derivatives, amine imide (AI) and polyamine, etc. Examples of additives include polysilicone-based, hydrocarbon-based and acrylic-based defoamers, polycarboxylic acid amides and other modifiers, etc.

The coloring agent is not particularly limited to a pigment or a coloring agent, and any coloring agent of any color among white coloring agent, blue coloring agent, green coloring agent, yellow coloring agent, purple coloring agent, black coloring agent, orange coloring agent, etc. can be used. Examples of the coloring agent include inorganic coloring agents such as titanium oxide (rutile type, rutile type) for white coloring agents, carbon black and acetylene black for black coloring agents, phthalocyanine series such as phthalocyanine green for green coloring agents and phthalocyanine blue or Lionol blue for blue coloring agents, anthraquinone series, diketopyrrolopyrrole series such as Chromophthal orange for orange coloring agents, and the like.

The non-reactive diluent is a diluent that can adjust the coating properties or drying properties of the photosensitive resin composition. Examples of the non-reactive diluent include organic solvents. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohydroquinone, aromatic hydrocarbons such as toluene and xylene, alcohols such as methanol, ethanol, propanol, and cyclohexanol, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, petroleum solvents such as petroleum ether and naphtha, solvents such as butyl solvent, carbitols such as carbitol and butyl carbitol, ethyl acetate, butyl acetate, solvent acetate, butyl solvent acetate, carbitol acetate, butyl carbitol acetate, ethylene glycol acetate, ethyl diglycol acetate and other esters. These may be used alone or in combination of two or more.

The method for producing the photosensitive resin composition of the present invention is not limited to a specific method. For example, the above-mentioned components are mixed in a predetermined ratio and then kneaded or mixed at room temperature (normal temperature) by a kneading means such as a three-roller, ball mill, sand mill, or a stirring means such as a super mixer or planetary mixer. In addition, before the above kneading or mixing, preliminary kneading or preliminary mixing can be carried out at room temperature (normal temperature) as necessary.

Next, examples of the use of the photosensitive resin composition of the present invention are described. First, a method of forming a solder resist film on a printed circuit board having a circuit pattern formed by etching a conductor foil is described using a dry film coated with the photosensitive resin composition of the present invention.

The dry film has a laminated structure of a support film (e.g., thermoplastic films such as polyethylene terephthalate film and polyester film), a solder resist layer coated on the support film, and a cover film (e.g., polyethylene film and polypropylene film) for protecting the solder resist layer. The photosensitive resin composition of the present invention is coated on the support film by a known method such as a roll coating method and a rod coater method to form a coating film, and the coating film is dried to form a solder resist layer on the support film. Thereafter, a cover film is laminated on the formed solder resist layer to manufacture a dry film having a coating film of the photosensitive resin composition of the present invention.

By peeling off the cover film of the dry film, the solder resist layer is bonded to the printed circuit board to form a solder resist film on the printed circuit board. Thereafter, if necessary, in order to evaporate the non-reactive diluent (organic solvent) in the photosensitive resin composition, it is heated at a temperature of about 70 to 120°C for 1 to 20 minutes to perform preliminary drying, and the non-reactive diluent (organic solvent) is evaporated from the photosensitive resin composition to make the surface of the solder resist film non-sticky. On the formed solder resist film, a negative film having a light-transmitting pattern outside the circuit pattern area is adhered, and ultraviolet rays (for example, a wavelength range of 300 to 400nm) are irradiated from the negative film. After that, the non-exposed area corresponding to the aforementioned area is removed by a dilute alkaline aqueous solution to develop the solder resist film. For the developing method, a spray method, a shower method, etc. are used. As the dilute alkaline aqueous solution used, for example, a 0.5-5 mass % sodium carbonate aqueous solution can be cited. After development, after curing (thermal curing treatment) for 20-80 minutes in a hot air circulation dryer at 130-170°C, a solder resist film with a target pattern can be formed on the printed circuit board.

Next, as an example of the use of the photosensitive resin composition of the present invention, a method of coating the photosensitive resin composition on a printed circuit board to form an insulating protective film (e.g., a solder resist film) is described. The photosensitive resin composition of the present invention obtained as described above is coated on a printed circuit board having a circuit pattern by screen printing, spray coating, rod coater method, applicator method, scraper coater method, knife coater method, roller coating method, gravure coater method, or other known coating methods to form a coating film at a desired thickness. Next, if necessary, the non-reactive diluent is evaporated, and pre-dried by heating at a temperature of about 60 to 100°C for about 15 to 60 minutes to form a non-sticky coating. Next, a negative film having a pattern that makes the area outside the circuit pattern transparent is adhered to the coating, and ultraviolet rays (for example, a wavelength range of 300 to 400nm) are irradiated from the top of the negative film to photoharden the coating. Then, the coating is developed by removing the non-exposed area corresponding to the aforementioned area with a dilute alkaline aqueous solution. The developing method uses a spray method, a spray method, etc. As the dilute alkaline aqueous solution used, for example, a 0.5 to 5 mass% sodium carbonate aqueous solution can be cited. Next, after curing (thermal curing treatment) for 20 to 80 minutes in a hot air circulation dryer at 130 to 170°C, the desired solder resist film can be formed on the printed circuit board. [Example]

Next, embodiments of the present invention will be described, but the present invention is not limited to these embodiments as long as the effects thereof are not exceeded.

Examples 1 to 9, Comparative Examples 1 to 3 The components shown in Table 1 below were mixed in the proportions shown in Table 1 below, and three rollers were used to mix and disperse at room temperature (25°C) to prepare the photosensitive resin composition used in Examples 1 to 9 and Comparative Examples 1 to 3. The amounts of the components shown in Table 1 below are expressed in parts by mass unless otherwise specified. In addition, the blank column of the amount in Table 1 below indicates that no addition is made.

The details of each component in Table 1 are as follows. (A) Photosensitive resin containing a carboxyl group ･KAYARAD ZAR-2000: solid content (resin content) 65% by mass, Nippon Kayaku Co., Ltd. KAYARAD ZAR-2000 is a polyacid-modified epoxy acrylate resin obtained by reacting acrylic acid with at least a portion of the epoxy groups of an epoxy resin (bisphenol A type epoxy resin) to obtain epoxy acrylate, and then reacting the hydroxyl group generated by the epoxy acrylate with a polyacid. (B) Antioxidants ･SumilizerGP: Compound of formula (1), Sumitomo Chemical Co., Ltd. ･Irganox1726: Compound of formula (2), BASF ･Irganox 1010: Phenolic antioxidant, BASF ･Irgafos 168: Phosphorus antioxidant, BASF (C) Photopolymerization initiator ･NCI-831: Oxime ester photopolymerization initiator, ADEKA ･OXE-02: Oxime ester photopolymerization initiator, BASF (D) Reactive diluent ･EBERCRYL8405: Daicel-Scitech Co., Ltd. (E) Epoxy compounds ･EPICRON 850-S: DIC Corporation

Extender pigments ･Heidi Light H42M: Showa Denko Co., Ltd. Flame retardant ･OP-935: Clariant Japan Hardening accelerator ･Melamine: Nissan Chemical Co., Ltd. ･DICY-7: Mitsubishi Chemical Co., Ltd. Additives ･X-50-1095C: Defoamer, Shin-Etsu Chemical Co., Ltd. Colorant ･Cromofutal DPP Orenji TR: Ciba Specialty Chemicals Non-reactive diluent ･EDGAC: Sanyo Chemicals Co., Ltd.

Test body preparation steps Using the prepared photosensitive resin composition, the following test bodies were manufactured. Substrate: Glass epoxy substrate, "FR4", copper foil thickness 25μm Substrate surface treatment: 5 mass% sulfuric acid treatment Coating: Screen printing Pre-drying: BOX furnace, 80℃, 20 minutes Exposure: Use direct drawing exposure machine (Nuvogo 80, Orbotech), exposure treatment under exposure conditions of 100-300mJ/ ^cm2 Alkaline development: 1 mass% _{Na2CO3 aqueous} solution, liquid temperature 30℃, spray pressure 0.2MPa, development time 60 seconds after hardening (heat treatment for this hardening): 150℃, 60 minutes

The thickness of the photocurable film of the test body obtained as described above was 20-23 μm.

Evaluation Items (1) Sensitivity In the above test body preparation step, the coated substrate was pre-dried at 80°C for 20 minutes, and a Step tablet (Kodak, 21) was set up for sensitivity measurement. The Step tablet was used to expose 100mJ/ ^cm2 as a test piece. After exposure, a 1 mass% _{Na2CO3 aqueous} solution was used for development at a spray pressure of 0.2MPa and a development time of 60 seconds. The exposed part that was not removed was expressed as a number (step number). The larger the step number, the better the photosensitivity.

(2) Alkali Development For the test specimen preparation step, the photosensitive resin composition was applied by spray coating instead of screen printing, and then pre-dried at 80°C for 20 to 80 minutes with intervals of 10 minutes as the test specimen. The test specimen was taken out of the pre-drying oven and developed under the alkaline development conditions of the test specimen preparation step. The removal state of the coating after development was visually observed, and the longest pre-drying time of the test specimen with the coating removed was measured.

(3) Plating properties Using the electroless nickel plating bath and electroless gold plating bath sold by OKU Pharmaceutical Co., Ltd., plating was performed under the conditions of 0.5μm nickel and 0.03μm gold. The state of plating was visually observed, and the plating properties were evaluated in the following 4 stages. ○: No abnormality on the plating surface. △: Slightly uneven plating. ×: The entire surface is unevenly plated. ××: Plating was not completed

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

As shown in Table 1, Examples 1 to 9 in which a compound having a phenolic hydroxyl group and phosphorus as component (B1) or a compound having a phenolic hydroxyl group and sulfur as component (B2) is formulated as an antioxidant have good sensitivity and can obtain photocurable materials having good alkali developability and metallization properties. Furthermore, Examples 4 and 7 show that even when a phenolic antioxidant is used in combination, a photocurable material having good sensitivity and good alkali developability and metallization properties can be obtained. In particular, in the comparison between Examples 1 to 4 and 8 and Examples 5 to 7 and 9, that is, the compound having a phenolic hydroxyl group and phosphorus as component (B1) and the compound having a phenolic hydroxyl group and sulfur as component (B2), the coating film can be removed even after a long pre-drying time, and the alkali developability is further improved.

In addition, for 100 parts by mass of the photosensitive resin containing a carboxyl group, Example 2, in which about 2 parts by mass of the compound having a phenolic hydroxyl group and phosphorus (B1) is added, has a higher sensitivity than Example 1, in which about 5 parts by mass of the compound having a phenolic hydroxyl group and phosphorus (B1) is added, and Example 8, in which about 10 parts by mass of the compound having a phenolic hydroxyl group and phosphorus (B1) is added. In addition, for 100 parts by mass of the photosensitive resin containing a carboxyl group, Example 2, in which about 2 parts by mass of the compound having a phenolic hydroxyl group and phosphorus (B1) is added, has a higher plating property at 300 mJ/cm ² than Example 4, in which about 1 part by mass of the compound having a phenolic hydroxyl group and phosphorus (B1) is added.

In addition, in Example 5, in which about 1 part by mass of the compound having a phenolic hydroxyl group and sulfur (B2) is added to 100 parts by mass of the photosensitive resin containing a carboxyl group, the alkali developing property is further improved compared with Example 9, in which about 2 parts by mass of the compound having a phenolic hydroxyl group and sulfur (B2) is added. In addition, in Example 5, in which about 1 part by mass of the compound having a phenolic hydroxyl group and sulfur (B2) is added to 100 parts by mass of the photosensitive resin containing a carboxyl group, the plating property at 300 mJ/cm ² is further improved compared with Example 6, in which about 0.5 parts by mass of the compound having a phenolic hydroxyl group and sulfur (B2) is added.

On the other hand, in Comparative Example 1 in which no antioxidant was added, plating properties could not be obtained, and in Comparative Example 2 in which a phenolic antioxidant was used as an antioxidant and Comparative Example 3 in which a phosphorus antioxidant was used, plating properties could not be obtained at 200 mJ/cm ² and 300 mJ/cm ^2. [Industrial Applicability]

The photosensitive resin composition of the present invention can form a photocurable film that does not impair the high sensitivity to ultraviolet rays and has excellent alkali developability, plating properties, etc. Therefore, it has high utilization value in the field of protective films such as solder resists formed on printed circuit boards, especially in the field of protective films such as solder resists formed on highly sensitized photosensitive resin compositions.

Claims (9)

A photosensitive resin composition, comprising (A) a photosensitive resin containing a carboxyl group, (B) an antioxidant, (C) a photopolymerization initiator, (D) a reactive diluent, and (E) an epoxy compound, wherein the antioxidant (B) is a compound containing (B1) a phenolic hydroxyl group and phosphorus, and the compound (B1) containing a phenolic hydroxyl group and phosphorus is contained in an amount of 2.0 parts by mass or more and 6.0 parts by mass or less per 100 parts by mass of the photosensitive resin (A) containing a carboxyl group, and the photopolymerization initiator (C) is an oxime ester-based photopolymerization initiator. A photosensitive resin composition, which contains (A) a photosensitive resin containing a carboxyl group, (B) an antioxidant, (C) a photopolymerization initiator, (D) a reactive diluent, and (E) an epoxy compound, wherein the aforementioned (B) antioxidant is a compound containing the aforementioned (B2) a phenolic hydroxyl group and sulfur, and the aforementioned (B2) compound containing a phenolic hydroxyl group and sulfur is contained in an amount of 0.50 parts by mass or more and 1.5 parts by mass or less per 100 parts by mass of the aforementioned (A) photosensitive resin containing a carboxyl group. The photosensitive resin composition of claim 1 or 2, wherein the aforementioned (B) antioxidant is contained in an amount of 0.40 parts by mass or more and 12.0 parts by mass or less for 100 parts by mass of the aforementioned (A) photosensitive resin containing a carboxyl group. The photosensitive resin composition of claim 1, wherein the compound (B1) having a phenolic hydroxyl group and phosphorus is a compound represented by the following formula (1);

The photosensitive resin composition of claim 2, wherein the compound (B2) having a phenolic hydroxyl group and sulfur is a compound represented by the following formula (2);

The photosensitive resin composition of claim 1, wherein the aforementioned oxime ester photopolymerization initiator is (Z)-(9-ethyl-6-nitro-9H-carbazole-3-yl)(4-((1-methoxypropane-2-yl)oxy)-2-methylphenyl)methanone O-acetyl oxime. A photocurable material of a photosensitive resin composition as claimed in any one of claims 1 to 6. A dry film having a photosensitive resin composition as described in any one of claims 1 to 6. A printed circuit board having a photocured product of the photosensitive resin composition of any one of claims 1 to 6.