Photosensitive resin composition, and print wiring board

Abstract

To provide a photosensitive resin composition capable of forming a cured film having excellent delustering appearance, and having excellent insulation reliability.SOLUTION: A photosensitive resin composition contains: (A) a carboxyl group-containing photosensitive resin; (B) a photoinitiator; (C) a reactive diluent; and (D) an epoxy compound, where the constituent (A) contains (A1) a carboxyl group-containing copolymer resin, and a gross value of a cured product of the photosensitive resin composition is 40 or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a photosensitive resin composition and a printed wiring board.

Background Art

[0002] As an insulating film of a printed wiring board, a cured film of a solder resist, which is a photo-developable photosensitive resin composition, may be used. On the other hand, the cured film of the photosensitive resin composition may be required to have a matte appearance depending on the usage conditions as a protective film. Therefore, a solder resist ink composition containing a carboxyl group-containing photosensitive resin, a photopolymerization initiator, an organic filler, a diluent, and an epoxy resin has been proposed (see Patent Document 1). The solder resist ink composition described in Patent Document 1 obtains a matte effect by blending an organic filler such as polymethacrylate particles and silicone resin.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the solder resist ink composition described in Patent Document 1, since the reactivity between the organic filler and the carboxyl group-containing photosensitive resin is low, there is a problem that the insulation reliability is insufficient.

[0005] An object of the present invention is to provide a photosensitive resin composition capable of forming a cured film having an excellent matte appearance and excellent insulation reliability, and a printed wiring board using the same.

Means for Solving the Problems

[0006] According to the present invention, there are provided a photosensitive resin composition and a printed wiring board as described below. [1] A photosensitive resin composition containing (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) a reactive diluent, and (D) an epoxy compound, wherein the component (A) contains (A1) a carboxyl group-containing photosensitive copolymer resin, and the gloss value of the cured product of the photosensitive resin composition is 40 or less. Photosensitive resin composition. [2] In the photosensitive resin composition according to [1], the weight average molecular weight of the component (A1) is 20,000 or more. Photosensitive resin composition. [3] In the photosensitive resin composition according to [1] or [2], the solid content acid value of the component (A1) is 90 mgKOH / g or more. Photosensitive resin composition. [4] In the photosensitive resin composition according to any one of [1] to [3], the component (B) contains 1-(4-morpholinophenyl)-2-(dimethylamino)-2-(4-methylbenzyl)-1-butanone and (9-ethyl-6-nitro-9H-carbazol-3-yl)(4-((1-methoxypropan-2-yl)oxy)-2-methylphenyl)methanol O-acetoxime. Photosensitive resin composition. [5] In the photosensitive resin composition according to any one of [1] to [4], the component (C) contains a caprolactone-modified (meth)acrylate. Photosensitive resin composition. [6] In the photosensitive resin composition according to any one of [1] to [5], furthermore, it contains cresol novolak type epoxy acrylate. Photosensitive resin composition. [7] In the photosensitive resin composition according to any one of [1] to [6], Furthermore, it contains N’-[3-[[[(dimethylamino)carbonyl]amino]methyl]-3,5,5-trimethylcyclohexyl]-N,N-dimethylurea, a photosensitive resin composition. [8] In the photosensitive resin composition according to any one of [1] to [7], wherein the cured product of the photosensitive resin composition has a black color tone, a photosensitive resin composition. [9] A printed wiring board comprising a solder resist film made of a cured product of the photosensitive resin composition according to any one of [1] to [8]. A printed wiring board. [Advantages of the Invention]

[0007] According to the present invention, there can be provided a photosensitive resin composition capable of forming a cured film having an excellent matte appearance and excellent insulation reliability, and a printed wiring board using the same. [Modes for Carrying Out the Invention]

[0008] [Photosensitive Resin Composition] First, the photosensitive resin composition according to the present embodiment will be described. The photosensitive resin composition according to the present embodiment contains (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) a reactive diluent, and (D) an epoxy compound, which will be described below. Further, the component (A) contains (A1) a carboxyl group-containing photosensitive copolymer resin, and it is necessary that the gloss value of the cured product of the photosensitive resin composition is 40 or less. From the viewpoint of an even more excellent matte appearance, the gloss value of the cured product is preferably 20 or less, more preferably 5 or less, still more preferably 3 or less, and particularly preferably 2 or less. The gloss value is the 60-degree glossiness measured using a microtri-gloss (manufactured by BYK-Chemie Japan).

[0009] [Component (A)] The (A) carboxyl group-containing photosensitive resin used in this embodiment needs to contain (A1) a carboxyl group-containing photosensitive copolymer resin. The component (A1) is a resin synthesized by at least a step including a copolymerization reaction, and is a resin having a carboxyl group and a photosensitive group. With this component (A1), the gloss of the cured film can be suppressed without significantly affecting various properties such as insulation reliability.

[0010] The solid content acid value of the component (A1) is not particularly limited, but from the viewpoints of alkali developability and the gloss of the cured film, it is preferably 40 mgKOH / g or more, and particularly preferably 90 mgKOH / g or more. On the other hand, this solid content acid value is preferably 200 mgKOH / g or less, and particularly preferably 150 mgKOH / g or less, from the viewpoint of preventing the dissolution of the exposed portion by the alkali developer.

[0011] The weight average molecular weight of the component (A1) is not particularly limited, but from the viewpoints of the toughness of the cured product and the gloss of the cured film, it is preferably 10,000 or more, and particularly preferably 20,000 or more. On the other hand, this weight average molecular weight is preferably 200,000 or less, and particularly preferably 50,000 or less, from the viewpoint of smooth alkali developability. The weight average molecular weight of the carboxyl group-containing photosensitive resin is a standard polystyrene conversion value measured by the gel permeation chromatography (GPC) method.

[0012] Examples of the component (A1) include a resin obtained by partially reacting a copolymer of (A11) an unsaturated carboxylic acid and a compound having an unsaturated double bond other than an unsaturated carboxylic acid with an epoxy group-containing unsaturated compound, and a resin obtained by subjecting an epoxy group of a copolymer of (A12) an epoxy group-containing unsaturated compound and a compound having an unsaturated double bond other than the epoxy group-containing unsaturated compound to an addition reaction with a carboxyl group-containing compound, and then reacting the resulting hydroxyl group with a saturated or unsaturated polybasic acid anhydride.

[0013] Examples of the unsaturated carboxylic acid used for the synthesis of the (A11) component include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, and vinylacetic acid. Among these, acrylic acid or methacrylic acid is preferable, and methacrylic acid is particularly preferable. Examples of the compound having an unsaturated double bond other than the unsaturated carboxylic acid include methyl methacrylate, methyl acrylate, ethyl methacrylate, cyclohexyl methacrylate, phenoxymethyl methacrylate, and 2-hydroxyethyl methacrylate. Examples of the epoxy group-containing unsaturated compound include glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, and 4-hydroxybutyl acrylate glycidyl ether. Among these, glycidyl methacrylate or 4-hydroxybutyl acrylate glycidyl ether is preferable, and glycidyl methacrylate is particularly preferable.

[0014] Examples of the epoxy group-containing unsaturated compound used for the synthesis of the (A12) component include glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, and 4-hydroxybutyl acrylate glycidyl ether. Examples of the compound having an unsaturated double bond other than the epoxy group-containing unsaturated compound include methyl methacrylate, methyl acrylate, ethyl methacrylate, cyclohexyl methacrylate, phenoxymethyl methacrylate, and 2-hydroxyethyl methacrylate. Examples of the carboxyl group-containing compound include acrylic acid or methacrylic acid. Examples of the saturated or unsaturated polybasic acid anhydride include acid anhydrides such as succinic acid, maleic acid, adipic acid, citric acid, phthalic acid, and tetrahydrophthalic acid.

[0015] Examples of the (A1) component include resins represented by the following structural formulas (A1-1) and (A1-2).

[0016] [Chem.]

[0017] In Structural Formulas (A1-1) and (A1-2), a, b, c, d, and e represent the number of each structural unit, and n represents the number of repetitions of the oxyethylene group. In Structural Formula (A1-1), a + b is preferably 0.5 or more and 0.7 or less, more preferably 0.6 or more and 0.65 or less. c is preferably 0.3 or more and 0.5 or less, more preferably 0.35 or more and 0.4 or less. b / (a + b) is preferably 0.4 or more and 0.6 or less, more preferably 0.5 or more and 0.55 or less. n is preferably 1 or more and 5 or less, more preferably 1 or more and 3 or less. In Structural Formula (A1-2), a is preferably 0.2 or more and 0.4 or less, more preferably 0.25 or more and 0.35 or less. b is preferably 0.01 or more and 0.15 or less, more preferably 0.03 or more and 0.08 or less. c + d is preferably 0.4 or more and 0.6 or less, more preferably 0.45 or more and 0.55 or less. e is preferably 0.1 or more and 0.3 or less, more preferably 0.15 or more and 0.2 or less. d / (c + d) is preferably 0.45 or more and 0.65 or less, more preferably 0.55 or more and 0.6 or less.

[0018] Component (A) may contain a carboxyl group-containing photosensitive resin other than Component (A1) (hereinafter also referred to as Component (A2)) within the range where the effects of the present invention can be exhibited. However, from the perspective of the gloss of the cured film, the blending amount of Component (A1) is preferably 75% by mass or more, more preferably 85% by mass or more, and particularly preferably 95% by mass or more with respect to 100% by mass of Component (A).

[0019] (Component (A2)) is not particularly limited, and examples thereof include a photosensitive carboxyl group-containing resin having one or more photosensitive unsaturated double bonds. Examples of the carboxyl group-containing photosensitive resin include a polybasic acid-modified radical polymerizable unsaturated monocarboxylated epoxy resin such as a polybasic acid-modified epoxy (meth)acrylate obtained by reacting at least a part of the epoxy groups of a polyfunctional epoxy resin having two or more epoxy groups in one molecule with a radical polymerizable unsaturated monocarboxylic acid such as acrylic acid or methacrylic acid (hereinafter sometimes referred to as “(meth)acrylic acid”), obtaining a radical polymerizable unsaturated monocarboxylated epoxy resin such as epoxy (meth)acrylate, and then reacting the resulting hydroxyl group with a polybasic acid or its anhydride.

[0020] Any polyfunctional epoxy resin having two or more functional groups can be used. The epoxy equivalent is not particularly limited, but is, for example, 1000 or less, preferably 100 or more and 500 or less. Examples of the polyfunctional epoxy resin include biphenyl type epoxy resins, naphthalene type epoxy resins, dicyclopentadiene type epoxy resins, rubber-modified epoxy resins (for example, silicone-modified epoxy resins, etc.), ε-caprolactone-modified epoxy resins, phenol novolac type epoxy resins (for example, epoxy resins such as bisphenol A type, bisphenol F type, bisphenol AD type, etc.), cresol novolac type epoxy resins (for example, о-cresol novolac type epoxy resins), bisphenol A novolac type epoxy resins, cycloaliphatic polyfunctional epoxy resins, glycidyl ester type polyfunctional epoxy resins, glycidyl amine type polyfunctional epoxy resins, heterocyclic polyfunctional epoxy resins, bisphenol-modified novolac type epoxy resins, polyfunctional modified novolac type epoxy resins, and condensate type epoxy resins of phenols and aromatic aldehydes having phenolic hydroxyl groups. Further, those obtained by introducing halogen atoms such as Br and Cl into these resins can also be used.

[0021] The radically polymerizable unsaturated monocarboxylic acid is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, etc. Among these, acrylic acid and methacrylic acid are preferred. The reaction method between the epoxy resin and the radically polymerizable unsaturated monocarboxylic acid is not particularly limited. For example, the epoxy resin and the radically polymerizable unsaturated monocarboxylic acid can be reacted by heating in a suitable diluent.

[0022] The polybasic acid or polybasic acid anhydride reacts with the hydroxyl group generated by the reaction between the epoxy resin and the radically polymerizable unsaturated monocarboxylic acid to introduce a free carboxyl group into the resin. The polybasic acid or its anhydride is not particularly limited, and either saturated or unsaturated ones can be used. Examples of the polybasic acid include succinic acid, maleic acid, adipic acid, citric acid, phthalic acid, tetrahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, 3-ethyltetrahydrophthalic acid, 4-ethyltetrahydrophthalic acid, hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid, 3-ethylhexahydrophthalic acid, 4-ethylhexahydrophthalic acid, methyltetrahydrophthalic acid, methylhexahydrophthalic acid, endomethylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, trimellitic acid, pyromellitic acid, and diglycolic acid, etc. Examples of the polybasic acid anhydride include the anhydrides of these acids. These compounds may be used alone or in combination of two or more.

[0023] The above-mentioned polybasic acid-modified unsaturated monocarboxylated epoxy resin can also be used as a carboxyl group-containing photosensitive resin. Further, if necessary, a glycidyl compound having one or more radically polymerizable unsaturated groups and an epoxy group can be reacted with the carboxyl group of the above-mentioned polybasic acid-modified unsaturated monocarboxylated epoxy resin to further introduce a radically polymerizable unsaturated group, and it may be used as a carboxyl group-containing photosensitive resin with improved photosensitivity.

[0024] This carboxyl group-containing photosensitive resin with improved photosensitivity is such that, due to the reaction of the glycidyl compound, the radically polymerizable unsaturated group binds to the side chain of the polybasic acid-modified unsaturated monocarboxylic acid epoxy resin skeleton, resulting in a resin with high photopolymerization reactivity and excellent photosensitive properties. The compound having one or more radically polymerizable unsaturated groups and an epoxy group is not particularly limited, and examples thereof include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, pentaerythritol triacrylate monoglycidyl ether, and the like. Note that a plurality of glycidyl groups may be present in one molecule. The above-described compound having one or more radically polymerizable unsaturated groups and an epoxy group may be used alone or in combination of two or more.

[0025] Component (A) is the main component of the photosensitive resin composition, and its blending amount is not particularly limited. For example, it is preferably 20% by mass or more, more preferably 30% by mass or more, and particularly preferably 40% by mass or more with respect to 100% by mass of the photosensitive resin composition.

[0026] [Component (B)] The (B) photoinitiator used in this embodiment is not particularly limited, and any known one can be appropriately used. Examples of such photoinitiators include 1-(4-morpholinophenyl)-2-(dimethylamino)-2-(4-methylbenzyl)-1-butanone, (9-ethyl-6-nitro-9H-carbazole-3-yl)(4-((1-methoxypropan-2-yl)oxy)-2-methylphenyl)methanone O-acetyl oxime, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime), 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, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, and ethyl p-dimethylaminobenzoate. These may be used alone or in combination of two or more.Among these, from the viewpoint of photosensitivity, it is preferable to use 1-(4-morpholinophenyl)-2-(dimethylamino)-2-(4-methylbenzyl)-1-butanone and (9-ethyl-6-nitro-9H-carbazol-3-yl)(4-((1-methoxypropan-2-yl)oxy)-2-methylphenyl)methanol O-acetoxime in combination.

[0027] The blending amount of the component (B) is not particularly limited. For example, from the viewpoints of photosensitivity and resolution, it is preferably 0.2 parts by mass or more and 12 parts by mass or less, more preferably 0.4 parts by mass or more and 10 parts by mass or less, and particularly preferably 0.6 parts by mass or more and 8 parts by mass or less with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin.

[0028] [Component (C)] The reactive diluent (C) used in this embodiment is, for example, a photopolymerizable monomer, which is a compound having at least one polymerizable double bond per molecule. The reactive diluent can improve the photocurability of the photosensitive resin composition.

[0029] Examples of the reactive diluent include 2-hydroxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, diethylene glycol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 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, neopentyl glycol hydroxypivalate di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified phosphoric acid di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, isocyanurate di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl)isocyanurate, propionic acid-modified dipentaerythritol penta(meth)acrylate, caprolactone-modified (meth)acrylate (such as caprolactone-modified dipentaerythritol hexa(meth)acrylate), and dipentaerythritol hexa(meth)acrylate. These may be used alone or in combination of two or more. Among these, from the viewpoint of various physical properties of the cured film, it is preferable to use caprolactone-modified (meth)acrylate.

[0030] (C) The blending amount is not particularly limited, but it is preferably 10 parts by mass or more and 150 parts by mass or less, and particularly preferably 40 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin.

[0031] [Component (D)] The (D) epoxy compound used in this embodiment is a compound having an epoxy group. By using this epoxy compound, the crosslinking density of the cured product of the alkali-soluble transparent resin composition can be increased. Examples of the epoxy compound include epoxy resins. Examples of the epoxy resin include bisphenol A type epoxy resins (for example, bisphenol A type liquid epoxy resins, bisphenol A type modified flexible epoxy resins, nuclear hydrogenated bisphenol A type liquid epoxy resins), novolak type epoxy resins (for example, phenol novolak type epoxy resins, o-cresol novolak type epoxy resins, p-tert-butylphenol novolak type), bisphenol F type and bisphenol S type epoxy resins (epoxy resins obtained by reacting bisphenol F or bisphenol S with epichlorohydrin), alicyclic epoxy resins (alicyclic epoxy resins having a cyclohexene oxide group, a tricyclodecane oxide group, a cyclopentene oxide group, etc.), dicyclopentadiene type epoxy resins, and adamantane type epoxy resins. These may be used alone or in combination of two or more.

[0032] From the viewpoint of obtaining sufficient curability, the blending amount of the (D) component is preferably 10 parts by mass or more and 120 parts by mass or less, more preferably 30 parts by mass or more and 90 parts by mass or less, based on 100 parts by mass of the carboxyl group-containing photosensitive resin.

[0033] [Epoxy acrylate] The photosensitive resin composition according to this embodiment may contain a cresol novolak type epoxy acrylate. By using this cresol novolak type epoxy acrylate, the photocurability of the photosensitive resin composition can be improved. As the cresol novolak type epoxy acrylate, known ones can be used.

[0034] The blending amount of cresol novolak type epoxy acrylate is not particularly limited, but it is preferably 5 parts by mass or more and 100 parts by mass or less, and particularly preferably 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin.

[0035] [Thermosetting catalyst] The photosensitive resin composition according to this embodiment may contain a thermosetting catalyst. With this cresol novolak type epoxy acrylate, the thermosetting property of the photosensitive resin composition can be improved. Examples of the thermosetting catalyst include boron trifluoride-amine complex, dicyandiamide (DICY) and its derivatives, organic acid hydrazide, diaminomaleonitrile (DAMN) and its derivatives, guanamine and its derivatives, melamine and its derivatives, amine imide (AI), aromatic dimethylurea, and polyamine. These may be used alone or in combination of two or more. Among these, from the viewpoint of curability, it is preferable to use aromatic dimethylurea in combination with another thermosetting catalyst. Examples of the aromatic dimethylurea include N’-[3-[[[(dimethylamino)carbonyl]amino]methyl]-3,5,5-trimethylcyclohexyl]-N,N-dimethylurea.

[0036] The blending amount of the thermosetting catalyst is not particularly limited, but it is preferably 1 part by mass or more and 20 parts by mass or less, and particularly preferably 3 parts by mass or more and 12 parts by mass or less with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin.

[0037] In the photosensitive resin composition of this embodiment, in addition to the above components (A) to (D), epoxy acrylate, and thermosetting catalyst, a filler pigment, various additives, flame retardants, colorants, and non-reactive diluents can be blended as necessary.

[0038] Examples of the extender pigment include talc, barium sulfate, alumina, mica, etc. However, from the viewpoint of bend resistance and the like, it is preferable to reduce the blending amount of the extender pigment, and it is particularly preferable not to use it. When using the extender pigment, the blending amount of the extender pigment is preferably 20 parts by mass or less, more preferably 1 part by mass or more and 10 parts by mass or less, based on 100 parts by mass of the carboxyl group-containing photosensitive resin.

[0039] Examples of the various additives include defoamers such as silicone-based, hydrocarbon-based and acrylic-based defoamers, organic fillers such as (meth)acrylic polymers, urethane beads and organic bentonite, and thixotropy imparting agents such as polycarboxylic acid amides. However, from the viewpoint of insulation reliability and the like, it is preferable to reduce the blending amount of the organic filler, and it is particularly preferable not to use it. When using the organic filler, the blending amount of the organic filler is preferably 20 parts by mass or less, more preferably 1 part by mass or more and 10 parts by mass or less, based on 100 parts by mass of the carboxyl group-containing photosensitive resin.

[0040] Examples of the flame retardant include aluminum hydroxide and phosphorus-based flame retardants. When the photosensitive resin composition is used for a flexible printed wiring board, a high degree of flame retardancy is required as compared with the case of using it for a rigid board with a thick plate thickness. Therefore, it is preferable to blend a flame retardant in the photosensitive resin composition. It is preferable to use aluminum hydroxide and a phosphorus-based flame retardant in combination as the flame retardant.Examples of phosphorus-based flame retardants include halogen-containing phosphate esters such as tris(chloroethyl) phosphate, tris(2,3-dichloropropyl) phosphate, tris(2-chloropropyl) phosphate, tris(2,3-bromopropyl) phosphate, tris(bromochloropropyl) phosphate, 2,3-dibromopropyl-2,3-chloropropyl phosphate, tris(tribromophenyl) phosphate, tris(dibromophenyl) phosphate, tris(tribromoneopentyl) phosphate; non-halogenated aliphatic phosphate esters such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate; non-halogenated aromatic phosphate esters such as triphenyl phosphate, cresyldiphenyl phosphate, dicresylphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, xylenyl diphenyl phosphate, tris(isopropylphenyl) phosphate, isopropylphenyl diphenyl phosphate, diisopropylphenyl phenyl phosphate, tris(trimethylphenyl) phosphate, tris(t-butylphenyl) phosphate, hydroxyphenyl diphenyl phosphate, octyl diphenyl phosphate; metal salts of phosphinic acids such as aluminum tris(diethylphosphinate), aluminum tris(methylethylphosphinate), aluminum tris(diphenylphosphinate), zinc bis(diethylphosphinate), zinc bis(methylethylphosphinate), zinc bis(diphenylphosphinate), titanyl bis(diethylphosphinate), titanium tetrakis(diethylphosphinate), titanyl bis(methylethylphosphinate), titanium tetrakis(methylethylphosphinate), titanyl bis(diphenylphosphinate), titanium tetrakis(diphenylphosphinate); phosphine oxide-based compounds such as diphenylvinylphosphine oxide, triphenylphosphine oxide, trialkylphosphine oxide, tris(hydroxyalkyl)phosphine oxide, etc. Among these, organic phosphate-based flame retardants are preferred.The compounding amount of the flame retardant is not particularly limited, but it is preferably 2 parts by mass or more and 60 parts by mass or less, more preferably 5 parts by mass or more and 50 parts by mass or less, based on 100 parts by mass of the carboxyl group-containing photosensitive resin.

[0041] The colorant may be a pigment or a dye and is not particularly limited. Also, the color of the colorant can be any color such as a white colorant, a blue colorant, a green colorant, a yellow colorant, an orange colorant, a red colorant, a purple colorant, and a black colorant. Examples of the inorganic colorants include titanium oxide as a white colorant, carbon black as a black colorant, and acetylene black. Examples of the organic colorants include phthalocyanine-based such as phthalocyanine green as a green colorant, phthalocyanine blue and rhodamine blue as a blue colorant, and diketopyrrolopyrrole-based such as chromophthal orange as an orange colorant. Since it is preferable that the cured product of the photosensitive resin composition according to the present embodiment has a black color tone, it is preferable to use a black colorant and a blue colorant in combination.

[0042] The non-reactive diluent is a component for adjusting the viscosity, coatability, or drying property of the photosensitive resin composition. Examples of the non-reactive diluent include organic solvents. Examples of the organic solvents include ketones such as methyl ethyl ketone, aromatic hydrocarbons such as toluene and xylene, alcohols such as methanol, n-propanol, isopropanol, cyclohexanol, and propylene glycol monomethyl ether, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, cellosolves such as cellosolve and butyl cellosolve, carbitols such as carbitol and butyl carbitol, and esters such as ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, diethylene glycol monomethyl ether acetate, ethyl diglycol acetate, and propylene glycol monomethyl ether acetate. The blending amount of the non-reactive diluent is not particularly limited, but is preferably 2 parts by mass or more and 50 parts by mass or less, and particularly preferably 5 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin.

[0043] The method for producing the photosensitive resin composition of the above-described embodiment is not limited to a specific method. For example, after blending the above components in a predetermined ratio, they can be kneaded or mixed at room temperature by a kneading means such as a three-roll mill, a ball mill, or a sand mill, or a stirring means such as a super mixer or a planetary mixer. Further, before the kneading or mixing, preliminary kneading or preliminary mixing may be performed as necessary.

[0044] [Printed Wiring Board] Next, the printed wiring board according to the present embodiment will be described. The printed wiring board according to the present embodiment includes a solder resist film made of the photosensitive resin composition of the above-described embodiment. And the printed wiring board according to the present embodiment can be produced by forming a solder resist film using the photosensitive resin composition of the above-described embodiment. The printed wiring board may be a flexible printed wiring board or a rigid printed wiring board.

[0045] Specifically, first, the photosensitive resin composition of the present embodiment is applied to the entire surface of the printed wiring board, and then pre-dried to form a coating film. Here, examples of the coating method of the coating film include a screen printing method, a bar coater method, an applicator method, a blade coater method, a knife coater method, a roll coater method, a gravure coater method, and a spray coater method. The conditions for pre-drying vary depending on the type of the photosensitive resin composition and are not particularly limited. For example, heating may be performed at a temperature in the range of 60°C or higher and 80°C or lower for 15 minutes or longer and 60 minutes or shorter. By such pre-drying, solvents and the like in the photosensitive resin composition can be volatilized to form a tack-free coating film. The thickness (DRY film thickness) of the coating film is not particularly limited, but is usually 5 μm or more and 200 μm or less, preferably 10 μm or more and 70 μm or less.

[0046] Note that a dry film may be used when forming the coating film. The dry film has a laminated structure including a support film (a thermoplastic resin film such as a polyethylene terephthalate film or a polyester film), a photosensitive resin composition layer coated on the support film, and a cover film (a thermoplastic resin film such as a polyethylene terephthalate film or a polyester film) for protecting the photosensitive resin composition layer. Then, by bonding the photosensitive resin composition layer and the printed wiring board while peeling off the cover film of the dry film, a coating film can be formed on the printed wiring board.

[0047] Next, a negative film having a pattern that makes the areas other than the lands of the circuit pattern translucent is adhered to the coating film of the photosensitive resin composition, and ultraviolet rays are irradiated from above. The exposure amount at this time can be appropriately set according to the type of the photosensitive resin composition and the type of the exposure apparatus. For example, the exposure amount is 10 mJ / cm 2It is preferably 1000 mJ / cm or less. 2 It is preferably below.

[0048] Next, the exposed coating film is developed by removing the unexposed area with a dilute alkaline aqueous solution. Thereby, an opening corresponding to the circuit pattern can be provided in the coating film. Examples of the developing method include a spray method and a shower method. Examples of the dilute alkaline aqueous solution include an aqueous sodium carbonate solution of 0.5 mass% or more and 5 mass% or less.

[0049] Next, the printed wiring board after development is heat-treated (hereinafter also referred to as post-cure in some cases). Thereby, an insulating coating film (solder resist film) having a target pattern can be formed on the printed wiring board. The heat treatment conditions vary depending on the type of the photosensitive resin composition and are not particularly limited. For example, as the heat treatment furnace, a hot air circulation dryer, a far-infrared furnace, etc. can be employed. Also, when using a hot air circulation dryer, the heat treatment temperature is preferably 130°C or higher and 170°C or lower, and the heat treatment time is preferably 30 minutes or longer and 120 minutes or shorter. Further, when using a far-infrared furnace, the heat treatment temperature is preferably 200°C or higher and 250°C or lower, and the heat treatment time is preferably 3 minutes or longer and 10 minutes or shorter.

Examples

[0050] Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited by these examples.

[0051] (Component (A1)) Carboxyl group-containing photosensitive copolymer resin A: The copolymer resin obtained in Preparation Example 1 below (Mw: 19000, solid content: 49.2 mass%, solvent: dipropylene glycol monomethyl ether, solid content acid value: 92.7 mgKOH / g) Carboxyl group-containing photosensitive copolymer resin B: The copolymer resin obtained in Preparation Example 2 below (Mw: 26000, solid content: 44.2% by mass, solvent: dipropylene glycol monomethyl ether, solid content acid value: 93.4 mgKOH / g) Carboxyl group-containing photosensitive copolymer resin C: Acrylic oligomer (Mw: 14000, solid content: 45%, solid content acid value: 66 mgKOH / g), trade name "Cyclomer P(ACA)Z251", manufactured by Daicel Ornex Co., Ltd. Carboxyl group-containing photosensitive copolymer resin D: Acrylic oligomer (Mw: 21000, solid content: 47%, solid content acid value: 111 mgKOH / g), trade name "Cyclomer P(ACA)Z300", manufactured by Daicel Ornex Co., Ltd. (Component (A2)) Carboxyl group-containing photosensitive resin A: Acid-modified cresol novolak type epoxy acrylate resin added with glycidyl methacrylate (solid content: 65% by mass, solvent: 17.5% by mass of diethylene glycol monoethyl ether acetate, 17.5% by mass of petroleum naphtha), trade name "Lipoxy SP-4785", manufactured by Resonac Co., Ltd. Carboxyl group-containing photosensitive resin B: Acid-modified biphenyl aralkyl type epoxy acrylate (solid content: 65% by mass, solvent: 35% by mass of diethylene glycol monoethyl ether acetate), trade name "ZCR-1601H", manufactured by Nippon Kayaku Co., Ltd. (Component (B)) Photoinitiator A: Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, trade name "Omnirad 819", manufactured by Nippon Cytec Industries Co., Ltd. Photoinitiator B: 2,4,6-Trimethylbenzoyldiphenylphosphine oxide, trade name "Omnirad TPO", manufactured by BASF Co., Ltd. Photoinitiator C: 1-(4-Morpholinophenyl)-2-(dimethylamino)-2-(4-methylbenzyl)-1-butanone, trade name "Omnirad 379EG", manufactured by BASF Co., Ltd. Photoinitiator D: (9-Ethyl-6-nitro-9H-carbazol-3-yl)(4-((1-methoxypropan-2-yl)oxy)-2-methylphenyl)methanone O-acyloxime, trade name "NCI-831", manufactured by ADEKA (Component (C)) Reactive diluent A: Caprolactone-modified acrylate (molecular weight: 1263), trade name "DPCA-60", manufactured by Nippon Kayaku Co., Ltd. Reactive diluent B: Caprolactone-modified acrylate (molecular weight: 1948), trade name "DPCA-120", manufactured by Nippon Kayaku Co., Ltd. (Component (D)) Epoxy compound A: Cresol novolak type epoxy resin, trade name "N-860", manufactured by DIC Corporation Epoxy compound B: Biphenyl novolak type epoxy resin, trade name "NC-3000", manufactured by Nippon Kayaku Co., Ltd. Epoxy compound C: Biphenyl type epoxy resin, trade name "YX-4000K", manufactured by Mitsubishi Chemical Corporation (Other components) Epoxy acrylate: Cresol novolak type epoxy acrylate (solid content: 65%, solvent: diethylene glycol monoethyl ether acetate 35% by mass), trade name "SP-4621BC", manufactured by Resonac Co., Ltd. Thermosetting catalyst A: Melamine, manufactured by Nissan Chemical Industries, Ltd. Thermosetting catalyst B: Dicyandiamide, trade name "DICY-7", manufactured by Mitsubishi Chemical Corporation Thermosetting catalyst C: N’-[3-[[[(dimethylamino)carbonyl]amino]methyl]-3,5,5-trimethylcyclohexyl]-N,N-dimethylurea, trade name "U-CAT 3513N", manufactured by San-Apro Ltd. Colorant A: Acetylene black, manufactured by Denka Co., Ltd. Colorant B: Phthalocyanine blue, manufactured by DIC Corporation Defoamer: Trade name "Flowlen AC-2300C", manufactured by Kyoeisha Chemical Co., Ltd. Flame retardant A: Organic phosphate, trade name "Exolit OP-935", manufactured by BASF SE Flame retardant B: Aluminum hydroxide, trade name "BF013STV", manufactured by Nippon Light Metal Co., Ltd. Inorganic filler: Talc, manufactured by Nippon Talc Co., Ltd. Organic filler: Urethane beads, manufactured by Dainichi Seiko Kogyo Co., Ltd. Ion catcher: Product name "IXE-100", manufactured by Toagosei Co., Ltd. Non-reactive diluent: Diethylene glycol monomethyl ether acetate, product name "EDGAC", manufactured by Sanyo Chemical Industries, Ltd.

[0052] [Preparation Example 1] 129 g of dipropylene glycol monomethyl ether (hereinafter also referred to as DPM) was charged into a 500 mL four-necked flask equipped with a stirrer, a thermometer, and a reflux tube. After heating to 120 °C under a nitrogen atmosphere, 40 g (0.47 mol) of methacrylic acid, 59 g (0.285 mol) of phenoxyethyl methacrylate ("SR-340" manufactured by Sartomer Co., Ltd., hereinafter also referred to as PEMA), and 5 g of dimethyl 2,2'-azobis(2-methylpropionate) (V-60 manufactured by Wako Pure Chemical Industries, Ltd.) were added dropwise over about 1 hour, and then stirred at 120 °C for 3 hours. Next, after lowering the temperature in the flask to 100 °C, while passing a mixed gas of air and nitrogen (air volume to nitrogen volume ratio is 1:2) into the flask at 200 mL / min, 50 g (0.25 mol) of 4-hydroxybutyl acrylate glycidyl ether (hereinafter also referred to as 4HBAGE), triphenylphosphine as a reaction catalyst, and methoxyhydroquinone as a polymerization inhibitor were added. After reacting at 100 °C for 5 hours, the reaction was continued at 115 °C until the acid value decreased, and a DPM solution (photosensitive copolymer resin A containing carboxyl groups) containing about 49% by mass of copolymer resin 1 was prepared. The weight average molecular weight of copolymer resin 1 was about 19,000 (polystyrene conversion), and the acid value of the DPM solution was 45.6 mgKOH / g.

[0053] [Preparation Example 2] The blending amount of methacrylic acid was changed to 0.32 mol. Instead of phenoxyethyl methacrylate, 0.18 mol of methyl methacrylate, 0.03 mol of 2-hydroxyethyl methacrylate, and 0.11 mol of cyclohexyl methacrylate were used. Further, instead of 4-hydroxybutyl acrylate glycidyl ether, 0.19 mol of glycidyl methacrylate was used. Otherwise, in the same manner as in Preparation Example 1, a DPM solution (carboxyl group-containing photosensitive copolymer resin B) containing about 44% by mass of copolymer resin 2 was prepared. The weight average molecular weight of copolymer resin 2 was about 26,000 (polystyrene conversion), and the acid value of the DPM solution was 41.3 mgKOH / g.

[0054] [Example 1] 43 parts by mass of carboxyl group-containing photosensitive copolymer resin A, 0.6 part by mass of photoinitiator A, 1 part by mass of photoinitiator B, 20 parts by mass of reactive diluent A, 10 parts by mass of epoxy compound A, 1 part by mass of thermosetting catalyst A, 0.7 part by mass of colorant A, 0.2 part by mass of colorant B, 2 parts by mass of defoaming agent, 10 parts by mass of flame retardant A, 3 parts by mass of inorganic filler, and 8.5 parts by mass of non-reactive diluent were put into a container and premixed with a stirrer, and then mixed and dispersed at room temperature using a three-roll mill to obtain a photosensitive resin composition. Then, a copper-clad laminate (conductor (Cu foil) thickness: 50 μm, substrate thickness: 1.6 mm) was surface-treated with a 5% by mass sulfuric acid aqueous solution, and the obtained photosensitive resin composition was applied by the screen printing method so that the dry film thickness became 20 to 23 μm to obtain a coated substrate. After coating, pre-drying was performed in a BOX furnace at 80°C for 20 minutes. After pre-drying, exposure was performed on the coating film with an exposure apparatus (direct exposure apparatus "Mms604" manufactured by ORC) under the condition that the exposure amount was 400 mJ / cm 2 . After exposure, development was performed using a 1% by mass aqueous sodium carbonate solution under the conditions of a development temperature of 30°C and a development time of 60 seconds. Then, post-curing was performed in a BOX furnace at 150°C for 60 minutes to form a solder resist film on the substrate, and an evaluation substrate was produced.

[0055] [Examples 2 to 10] A photosensitive resin composition was obtained in the same manner as in Example 1, except that each material was blended according to the composition shown in Table 1. An evaluation substrate was obtained in the same manner as in Example 1, except that the exposure amount was set to the numerical value of the sensitivity evaluation result shown in Table 1. [Comparative Examples 1 to 4] A photosensitive resin composition was obtained in the same manner as in Example 1, except that each material was blended according to the composition shown in Table 1. An evaluation substrate was obtained in the same manner as in Example 1, except that the exposure amount was set to the numerical value of the sensitivity evaluation result shown in Table 1.

[0056] [Evaluation of Photosensitive Resin Composition] The evaluation of the photosensitive resin composition (sensitivity evaluation, gloss value, adhesion, electrical insulation) was carried out by the following methods. The obtained results are shown in Table 1. (1) Sensitivity Evaluation For the coated substrate after pre-drying at 80°C for 20 minutes, a step tablet for sensitivity measurement (Kodak 21 steps) was installed, and 100 mJ / cm 2 , 200 mJ / cm 2 , 300 mJ / cm 2 , and 400 mJ / cm 2 exposures were performed under each condition. After development for 60 seconds at a spray pressure of 2.0 kg / cm 2 using a 1% aqueous sodium carbonate solution, the non-removed part of the exposed area was represented by a number (step number). Then, the exposure amount at which the step number reached 8 steps was determined. (2) Gloss Value The cured coating film of the evaluation substrate was measured for 60-degree glossiness (gloss value) using a micro trigloss (manufactured by BYK-Chemie Japan) to evaluate the matte appearance. The 60-degree glossiness was displayed by rounding off the third digit after rounding the significant figures of the average value to two digits. (3) Adhesion For the cured coating film of the evaluation substrate, an adhesion test was performed according to JIS K5600-5-6. Then, the adhesion was evaluated according to the following criteria. ◎: No peeling. ○: The peeling area is less than 5%. △: The peeling area is 5% or more and less than 50%. ×: The peeling area is 50% or more. (4) Electrical insulation Under the same conditions as in the manufacturing process of the evaluation substrate, a cured coating film of the photosensitive resin composition was formed on a comb-shaped test pattern (line width: 30 μm, line pitch: 30 μm) to produce a test piece for insulation evaluation. A DC voltage of 50 V was applied in an atmosphere of 85°C and 85% humidity, and after leaving it for 500 hours, the test piece for insulation evaluation was taken out of the tank and the insulation resistance value was measured. Then, the electrical insulation was evaluated according to the following criteria. ○: The insulation resistance value is 1×10 12 Ω or more. △: The insulation resistance value is 1×10 7 Ω or more and less than 1×10 12 Ω. ×: The insulation resistance value is less than 1×10 7 Ω.

[0057]

Table 1

[0058] As is clear from the results shown in Table 1, when the photosensitive resin composition of the present invention was used (Examples 1 to 10), it was confirmed that all the results of sensitivity evaluation, gloss value, adhesion, and electrical insulation were good. Therefore, according to the present invention, it was confirmed that a photosensitive resin composition capable of forming a cured film having an excellent matte appearance and excellent insulation reliability can be obtained.

Industrial applicability

[0059] The photosensitive resin composition of the present invention can be suitably used as a technique for forming an insulating coating film having a pattern on a printed wiring board or the like.

Claims

1. A photosensitive resin composition containing (A) a carboxyl group-containing photosensitive resin, (B) a photoinitiator, (C) a reactive diluent, and (D) an epoxy compound, wherein the component (A) contains (A1) a carboxyl group-containing photosensitive copolymer resin, and the gloss value of the cured product of the photosensitive resin composition is 40 or less. A photosensitive resin composition.

2. The photosensitive resin composition according to Claim 1, wherein the weight average molecular weight of the component (A1) is 20,000 or more. A photosensitive resin composition.

3. The photosensitive resin composition according to Claim 1 or Claim 2, wherein the solid content acid value of the component (A1) is 90 mgKOH / g or more. A photosensitive resin composition.

4. The photosensitive resin composition according to Claim 1 or Claim 2, wherein the component (B) contains 1-(4-morpholinophenyl)-2-(dimethylamino)-2-(4-methylbenzyl)-1-butanone and (9-ethyl-6-nitro-9H-carbazol-3-yl)(4-(((1-methoxypropan-2-yl)oxy)-2-methylphenyl)methanol O-acetoxime. A photosensitive resin composition.

5. The photosensitive resin composition according to Claim 1 or Claim 2, wherein the component (C) contains a caprolactone-modified (meth)acrylate. A photosensitive resin composition.

6. The photosensitive resin composition according to Claim 1 or Claim 2, further containing cresol novolak type epoxy acrylate. A photosensitive resin composition.

7. The photosensitive resin composition according to Claim 1 or Claim 2, further containing N'-[3-[[[(dimethylamino)carbonyl]amino]methyl]-3,5,5-trimethylcyclohexyl]-N,N-dimethylurea. A photosensitive resin composition.

8. The photosensitive resin composition according to Claim 1 or Claim 2, wherein the color tone of the cured product of the photosensitive resin composition is black. A photosensitive resin composition.

9. A printed wiring board comprising a solder resist film made of a cured product of the photosensitive resin composition according to Claim 1 or Claim 2. A printed wiring board.

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