Photosensitive resin composition and printed circuit 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 circuit board. [Background technology]

[0002] A cured film of solder resist, a photosensitive resin composition of the photodevelopable type, is sometimes used as an insulating coating for printed circuit boards. 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 incorporating organic fillers such as polymethacrylate particles and silicone resin. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2006-040935 [Overview of the Initiative] [Problems that the invention aims to solve]

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

[0005] The present invention aims to provide a photosensitive resin composition capable of forming a cured film having an excellent matte appearance and excellent insulating reliability, and a printed circuit board using the same. [Means for solving the problem]

[0006] According to the present invention, the following photosensitive resin composition and printed circuit board are provided. [1] A photosensitive resin composition comprising (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) a reactive diluent, and (D) an epoxy compound, The above component (A) contains (A1) a carboxyl group-containing photosensitive copolymer resin, The gloss value of the cured product of the aforementioned photosensitive resin composition is 40 or less. Photosensitive resin composition. [2] In the photosensitive resin composition described in [1], The weight-average molecular weight of component (A1) is 20,000 or more. Photosensitive resin composition. [3] In the photosensitive resin composition described in [1] or [2], The solid content acid value of component (A1) is 90 mg KOH / g or more. Photosensitive resin composition. [4] In the photosensitive resin composition described in any of [1] to [3], The aforementioned component (B) contains 1-(4-morpholinophenyl)-2-(dimethylamino)-2-(4-methylbenzyl)-1-butanone and (9-ethyl-6-nitro-9H-carbazole-3-yl)(4-((1-methoxypropan-2-yl)oxy)-2-methylphenyl)methanone O-acetyloxime. Photosensitive resin composition. [5] In the photosensitive resin composition described in any of [1] to [4], The aforementioned component (C) contains caprolactone-modified (meth)acrylate. Photosensitive resin composition. In the photosensitive resin composition described in any of [6] [1] to [5], Furthermore, it contains cresol novolac type epoxy acrylate, Photosensitive resin composition. In the photosensitive resin composition described in any of [7] [1] to [6], Furthermore, it contains N'-[3-[[[(dimethylamino)carbonyl]amino]methyl]-3,5,5-trimethylcyclohexyl]-N,N-dimethylurea, Photosensitive resin composition. In the photosensitive resin composition described in any of [8] [1] to [7], The cured product of the aforementioned photosensitive resin composition is black in color. Photosensitive resin composition. [9] A solder resist film comprising a cured product of a photosensitive resin composition described in any of [1] to [8], Printed circuit board. [Effects of the Invention]

[0007] According to the present invention, a photosensitive resin composition capable of forming a cured film having an excellent matte appearance and excellent insulating reliability can be provided, as well as a printed wiring board using the same. [Modes for carrying out the invention]

[0008] [Photosensitive resin composition] First, the photosensitive resin composition according to this embodiment will be described. The photosensitive resin composition according to this embodiment contains (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) a reactive diluent, and (D) an epoxy compound, as described below. Furthermore, component (A) contains (A1) a carboxyl group-containing photosensitive copolymer resin, and the gloss value of the cured product of the photosensitive resin composition must be 40 or less. From the viewpoint of achieving a superior matte appearance, the gloss value of the cured product is preferably 20 or less, more preferably 5 or less, even more preferably 3 or less, and particularly preferably 2 or less. The gloss value is the 60-degree gloss measured using Microtrigloss (manufactured by Bic Chemie Japan).

[0009] [(A) component] The photosensitive resin containing a carboxyl group (A) used in this embodiment needs to contain a photosensitive copolymer resin containing a carboxyl group (A1). 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. By this component (A1), the gloss of the cured film can be suppressed without significantly affecting various properties such as insulation reliability.

[0010] (A1) component's solid content acid value 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, from the viewpoint of preventing the dissolution of the exposed portion by the alkali developer, this solid content acid value is preferably 200 mgKOH / g or less, and particularly preferably 150 mgKOH / g or less.

[0011] (A1) component's weight average molecular weight 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, from the viewpoint of smooth alkali developability, this weight average molecular weight is preferably 200,000 or less, and particularly preferably 50,000 or less. The weight average molecular weight of the photosensitive resin containing a carboxyl group is the standard polystyrene conversion value measured by the gel permeation chromatography (GPC) method.

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

[0013] Examples of unsaturated carboxylic acids used in the synthesis of component (A11) include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, and vinylacetic acid. Among these, acrylic acid or methacrylic acid is preferred, and methacrylic acid is particularly preferred. Other compounds having unsaturated double bonds besides unsaturated carboxylic acids include methyl methacrylate, methyl acrylate, ethyl methacrylate, cyclohexyl methacrylate, phenoxymethyl methacrylate, and 2-hydroxyethyl methacrylate. Examples of epoxy group-containing unsaturated compounds 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 preferred, and glycidyl methacrylate is particularly preferred.

[0014] Examples of epoxy group-containing unsaturated compounds used in the synthesis of component (A12) include glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, and 4-hydroxybutyl acrylate glycidyl ether. Other unsaturated double bond compounds besides epoxy group-containing unsaturated compounds include methyl methacrylate, methyl acrylate, ethyl methacrylate, cyclohexyl methacrylate, phenoxymethyl methacrylate, and 2-hydroxyethyl methacrylate. Examples of carboxyl group-containing compounds include acrylic acid or methacrylic acid. Examples of saturated or unsaturated polybasic acid anhydrides include succinic acid, maleic acid, adipic acid, citric acid, phthalic acid, and tetrahydrophthalic acid.

[0015] (A1) Component includes resins represented by the following structural formulas (A1-1) and (A1-2).

[0016] [ka]

[0017] In structural formulas (A1-1) and (A1-2), a, b, c, d, and e represent the number of each constituent unit, and n represents the number of repeating oxyethylene groups. In structural formula (A1-1), a+b is preferably 0.5 to 0.7, and more preferably 0.6 to 0.65. c is preferably 0.3 to 0.5, and more preferably 0.35 to 0.4. b / (a+b) is preferably 0.4 to 0.6, and more preferably 0.5 to 0.55. n is preferably 1 to 5, and more preferably 1 to 3. In structural formula (A1-2), a is preferably 0.2 to 0.4, and more preferably 0.25 to 0.35. b is preferably 0.01 to 0.15, and more preferably 0.03 to 0.08. c+d is preferably 0.4 to 0.6, and more preferably 0.45 to 0.55. e is preferably 0.1 to 0.3, and more preferably 0.15 to 0.2. d / (c+d) is preferably 0.45 to 0.65, and more preferably 0.55 to 0.6.

[0018] Component (A) may contain a carboxyl group-containing photosensitive resin other than component (A1) (hereinafter also referred to as component (A2)) to the extent that the effects of the present invention can be exhibited. However, from the viewpoint of gloss of the cured film, the amount of component (A1) blended is preferably 75% by mass or more, more preferably 85% by mass or more, and particularly preferably 95% by mass or more, based on 100% by mass of component (A).

[0019] (A2) The component is not particularly limited, and examples include photosensitive carboxyl group-containing resins having one or more photosensitive unsaturated double bonds. Examples of carboxyl group-containing photosensitive resins include polybasic acid-modified radical polymerizable unsaturated monocarboxylic acid-containing epoxy resins such as polybasic acid-modified epoxy (meth)acrylate, which are obtained by reacting at least a portion 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 of acrylic acid or methacrylic acid (hereinafter sometimes referred to as "(meth)acrylic acid") to obtain a radical polymerizable unsaturated monocarboxylic acid-modified epoxy resin such as epoxy (meth)acrylate, and then further reacting the resulting hydroxyl groups with a polybasic acid or its anhydride.

[0020] Any polyfunctional epoxy resin can be used as long as it is a bifunctional or more functional epoxy resin. The epoxy equivalent is not particularly limited, but for example, it is 1000 or less, and preferably 100 to 500. Examples of polyfunctional epoxy resins include biphenyl-type epoxy resins, naphthalene-type epoxy resins, dicyclopentadiene-type epoxy resins, rubber-modified epoxy resins (e.g., silicone-modified epoxy resins), ε-caprolactone-modified epoxy resins, phenol novolac-type epoxy resins (e.g., bisphenol A-type, bisphenol F-type, bisphenol AD-type epoxy resins), cresol novolac-type epoxy resins (e.g., o-cresol novolac-type epoxy resins), bisphenol A novolac-type epoxy resins, cyclic aliphatic polyfunctional epoxy resins, glycidyl ester-type polyfunctional epoxy resins, glycidylamine-type polyfunctional epoxy resins, heterocyclic polyfunctional epoxy resins, bisphenol-modified novolac-type epoxy resins, polyfunctionally modified novolac-type epoxy resins, and condensate-type epoxy resins of phenols and aromatic aldehydes having phenolic hydroxyl groups. Furthermore, resins into which halogen atoms such as Br and Cl have been introduced are also available.

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

[0022] Polybasic acids or polybasic anhydrides introduce free carboxyl groups into epoxy resins by reacting with hydroxyl groups generated by the reaction of epoxy resins with radically polymerizable unsaturated monocarboxylic acids. The polybasic acid or its anhydride is not particularly limited; both saturated and unsaturated forms can be used. Examples of polybasic acids 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. Examples of polybasic acid anhydrides include these anhydrides. These compounds may be used individually or in mixtures of two or more.

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

[0024] This carboxyl group-containing photosensitive resin, with its improved photosensitivity, exhibits high photopolymerization reactivity and excellent photosensitive properties because the radically polymerizable unsaturated group is bonded to the side chain of the polybasic acid-modified unsaturated monocarboxylated epoxy resin skeleton through the reaction of the glycidyl compound. The compound having one or more radically polymerizable unsaturated groups and epoxy groups is not particularly limited, but examples include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and pentaerythritol triacrylate monoglycidyl ether. Note that a single molecule may contain multiple glycidyl groups. The above-mentioned compounds having one or more radically polymerizable unsaturated groups and epoxy groups may be used individually or in combination of two or more.

[0025] Component (A) is the main component of the photosensitive resin composition, and its amount is not particularly limited, but 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, based on 100% by mass of the photosensitive resin composition.

[0026] [(B) Component] The (B) photopolymerization initiator used in this embodiment is not particularly limited, and any known one can be used as appropriate. Examples of photopolymerization initiators include 1-(4-morpholinophenyl)-2-(dimethylamino)-2-(4-methylbenzyl)-1-butanone, (9-ethyl-6-nitro-9H-carbazole-3-yl)(4-((1-methoxypropane-2-yl)oxy)-2-methylphenyl)methanone O-acetyloxime, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethanolone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyloxime), benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, and 2,2-dimethoxy-2-phenylacetophenone. Examples include 2,2-diethoxy-2-phenylacetophenone, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorbenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, and p-dimethylaminobenzoate ethyl ester. These may be used individually or in combination of two or more types.Furthermore, 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-carbazole-3-yl)(4-((1-methoxypropan-2-yl)oxy)-2-methylphenyl)methanone O-acetyloxime in combination.

[0027] (B) The amount of component is not particularly limited, but for example, from the viewpoint 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, per 100 parts by mass of the carboxyl group-containing photosensitive resin.

[0028] [(C) component] The (C) reactive diluent 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] Reactive diluents 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, hydroxypivalate neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, and ethylene oxide-modified phosphate di(meth)acrylate. Examples include acrylates, 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 individually or in combination of two or more. Among these, caprolactone modified (meth)acrylate is preferred from the viewpoint of the various physical properties of the cured film.

[0030] The amount of component (C) is not particularly limited, but 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, per 100 parts by mass of the carboxyl group-containing photosensitive resin.

[0031] [(D) component] The epoxy compound (D) used in this embodiment is a compound having an epoxy group. This epoxy compound can increase the crosslinking density of the cured product of the alkali-soluble transparent resin composition. Examples of epoxy compounds include epoxy resins. Examples of epoxy resins include bisphenol A type epoxy resins (e.g., bisphenol A type liquid epoxy resin, bisphenol A type modified flexible epoxy resin, nuclear hydrogenated bisphenol A type liquid epoxy resin), novolac type epoxy resins (e.g., phenol novolac type epoxy resin, o-cresol novolac type epoxy resin, p-tert-butylphenol novolac 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 cyclohexene oxide groups, tricyclodecane oxide groups, cyclopentene oxide groups, etc.), dicyclopentadiene type epoxy resins, and adamantane type epoxy resins. These may be used individually or in combination of two or more types.

[0032] (D) The amount of component (D) is preferably 10 to 120 parts by mass, and more preferably 30 to 90 parts by mass, per 100 parts by mass of the carboxyl group-containing photosensitive resin, from the viewpoint of obtaining sufficient curability.

[0033] [Epoxy acrylate] The photosensitive resin composition according to this embodiment may contain a cresol novolac type epoxy acrylate. This cresol novolac type epoxy acrylate can improve the photocurability of the photosensitive resin composition. Known cresol novolac type epoxy acrylates can be used.

[0034] The amount of cresol novolac type epoxy acrylate blended is not particularly limited, but 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, per 100 parts by mass of carboxyl group-containing photosensitive resin.

[0035] [Thermosetting catalyst] The photosensitive resin composition according to this embodiment may contain a thermosetting catalyst. This cresol novolac type epoxy acrylate can improve the thermosetting properties of the photosensitive resin composition. Examples of thermosetting catalysts include boron trifluoride-amine complex, dicyandiamide (DICY) and its derivatives, organic acid hydrazides, diaminomaleonitrile (DAMN) and its derivatives, guanamine and its derivatives, melamine and its derivatives, amineimide (AI), aromatic dimethylurea, and polyamines. These may be used individually 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 aromatic dimethylurea include N'-[3-[[[(dimethylamino)carbonyl]amino]methyl]-3,5,5-trimethylcyclohexyl]-N,N-dimethylurea.

[0036] The amount of thermosetting catalyst is not particularly limited, but is preferably 1 to 20 parts by mass, and particularly preferably 3 to 12 parts by mass, per 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, extender pigments, various additives, flame retardants, colorants, and non-reactive diluents may be added as needed.

[0038] Examples of extender pigments include talc, barium sulfate, alumina, and mica. However, from the viewpoint of flexibility and other factors, it is preferable to reduce the amount of extender pigments used, and it is particularly preferable not to use them at all. When extender pigments are used, the amount of extender pigment used is preferably 20 parts by mass or less, and more preferably 1 to 10 parts by mass, per 100 parts by mass of the carboxyl group-containing photosensitive resin.

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

[0040] Examples of flame retardants include aluminum hydroxide and phosphorus-based flame retardants. When a photosensitive resin composition is used in a flexible printed circuit board, a higher level of flame retardancy is required compared to when it is used in a rigid board with a thicker board thickness. Therefore, it is preferable to incorporate a flame retardant into the photosensitive resin composition. It is preferable to use a combination of aluminum hydroxide and phosphorus-based flame retardants.Examples of phosphorus-based flame retardants include halogen-containing phosphorus-based Non-halogenated aliphatic phosphate esters; such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, and tributoxyethyl phosphate; triphenyl phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, tricresyl phosphate, trixylenyl phosphate, xylenyl diphenyl phosphate, tris(isopropylphenyl) phosphate, isopropylphenyl diphenyl phosphate, diisopropylphenyl Examples include non-halogenated aromatic phosphate esters such as propylphenylphenyl phosphate, tris(trimethylphenyl) phosphate, tris(t-butylphenyl) phosphate, hydroxyphenyldiphenyl phosphate, and octyldiphenyl phosphate; metal salts of phosphinic acid such as aluminum trisdiethylphosphinate, aluminum trismethylethylphosphinate, aluminum trisdiphenylphosphinate, zinc bisdiethylphosphinate, zinc bismethylethylphosphinate, zinc bisdiphenylphosphinate, titanyl bisdiethylphosphinate, titanium tetrakisdiethylphosphinate, titanium bismethylethylphosphinate, titanium tetrakismethylethylphosphinate, titanyl bisdiphenylphosphinate, and titanium tetrakisdiphenylphosphinate; and phosphin oxide compounds such as diphenylvinylphosphin oxide, triphenylphosphin oxide, trialkylphosphin oxide, and tris(hydroxyalkyl)phosphin oxide. Of these, organophosphate-based flame retardants are preferred.The amount of flame retardant is not particularly limited, but is preferably 2 parts by mass or more and 60 parts by mass or less, and more preferably 5 parts by mass or more and 50 parts by mass or less, per 100 parts by mass of carboxyl group-containing photosensitive resin.

[0041] The coloring agent may be a pigment or a dye, and is not particularly limited. Furthermore, any coloring agent can be used, including white, blue, green, yellow, orange, red, purple, and black coloring agents. Examples of inorganic coloring agents include titanium dioxide (a white coloring agent) and carbon black and acetylene black (black coloring agents). Examples of organic coloring agents include phthalocyanine green (a green coloring agent), phthalocyanine-based blue coloring agents such as phthalocyanine blue and leonol blue, and diketopyrrolopyrrole-based orange coloring agents such as chromophthal orange. Since the cured product of the photosensitive resin composition according to this embodiment is preferably black, it is preferable to use both a black coloring agent and a blue coloring agent.

[0042] Non-reactive diluents are components used to adjust the viscosity, coating properties, or drying properties of a photosensitive resin composition. Examples of non-reactive diluents include organic solvents. Examples of 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 amount of non-reactive diluent is not particularly limited, but is preferably 2 to 50 parts by mass, and particularly preferably 5 to 25 parts by mass, per 100 parts by mass of the carboxyl group-containing photosensitive resin.

[0043] The method for producing the photosensitive resin composition of this embodiment described above is not limited to a specific method. For example, after blending each of the above components in a predetermined proportion, the composition can be produced by kneading or mixing at room temperature using a kneading means such as a three-roll mill, ball mill, or sand mill, or by a stirring means such as a super mixer or planetary mixer. Furthermore, pre-kneading or pre-mixing may be performed before the kneading or mixing as needed.

[0044] [Printed circuit board] Next, a printed circuit board according to this embodiment will be described. The printed circuit board according to this embodiment comprises a solder resist film made of the photosensitive resin composition of this embodiment described above. The printed circuit board according to this embodiment can be manufactured by forming a solder resist film using the photosensitive resin composition of this embodiment described above. The printed circuit board may be a flexible printed circuit board or a rigid printed circuit board.

[0045] Specifically, first, the photosensitive resin composition of this embodiment is applied to the entire surface of the printed circuit board, and then pre-dried to form a coating film. Here, examples of coating methods include screen printing, bar coating, applicator coating, blade coating, knife coating, roll coating, gravure coating, and spray coating. The pre-drying conditions vary depending on the type of photosensitive resin composition and are not particularly limited, but for example, heating at a temperature in the range of 60°C to 80°C for a period of 15 minutes to 60 minutes is sufficient. Such pre-drying volatilizes solvents and other substances in the photosensitive resin composition, allowing for the formation of a tack-free coating film. The thickness of the coating film (DRY film thickness) is not particularly limited, but is usually between 5 μm and 200 μm, and preferably between 10 μm and 70 μm.

[0046] Furthermore, a dry film may be used when forming the coating. The dry film has a laminated structure comprising a support film (a thermoplastic resin film such as polyethylene terephthalate film or polyester film), a photosensitive resin composition layer coated on the support film, and a cover film (a thermoplastic resin film such as polyethylene terephthalate film or polyester film) that protects the photosensitive resin composition layer. By peeling off the cover film of the dry film and bonding the photosensitive resin composition layer to the printed circuit board, a coating can be formed on the printed circuit board.

[0047] Next, a negative film having a pattern in which areas other than the lands of the circuit pattern are translucent is placed in close contact with the photosensitive resin composition coating, and ultraviolet light is irradiated from above. The exposure dose at this time can be appropriately set depending on the type of photosensitive resin composition and the type of exposure device. For example, the exposure dose may be 10 mJ / cm². 2More than 1000mJ / cm 2 The following is preferable:

[0048] Next, the exposed coating is developed by removing the unexposed areas with a dilute alkaline aqueous solution. This allows openings corresponding to the circuit pattern to be created in the coating. Examples of development methods include the spray method and the shower method. Examples of dilute alkaline aqueous solutions include aqueous solutions of sodium carbonate containing 0.5% to 5% by mass.

[0049] Next, the developed printed circuit board is subjected to heat treatment (hereinafter sometimes referred to as post-curing). This allows for the formation of an insulating film (solder resist film) with the desired pattern on the printed circuit board. The heat treatment conditions vary depending on the type of photosensitive resin composition and are not particularly limited. For example, a hot air circulation type dryer and a far-infrared furnace can be used as the heat treatment furnace. When using a hot air circulation type dryer, the heat treatment temperature is preferably 130°C to 170°C, and the heat treatment time is preferably 30 minutes to 120 minutes. Furthermore, when using a far-infrared furnace, the heat treatment temperature is preferably 200°C to 250°C, and the heat treatment time is preferably 3 minutes to 10 minutes. [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 in any way by these examples.

[0051] (Component A1) Carboxyl group-containing photosensitive copolymer resin A: Copolymer resin obtained in Preparation Example 1 below (Mw: 19000, Solids content: 49.2% by mass, Solvent: Dipropylene glycol monomethyl ether, Solids content acid value: 92.7 mg KOH / g) Carboxyl group-containing photosensitive copolymer resin B: Copolymer resin obtained in Preparation Example 2 below (Mw: 26000, Solids content: 44.2% by mass, Solvent: Dipropylene glycol monomethyl ether, Solids content acid value: 93.4 mg KOH / g) Carboxyl group-containing photosensitive copolymer resin C: Acrylic oligomer (Mw: 14000, Solids content: 45%, Solids content acid value: 66 mg KOH / g), Product name "Cychromer P(ACA)Z251", Manufactured by Daicel Ornex Co., Ltd. Carboxyl group-containing photosensitive copolymer resin D: Acrylic oligomer (Mw: 21000, Solids content: 47%, Solids content acid value: 111 mg KOH / g), Product name "Cychromer P(ACA)Z300", Manufactured by Daicel Ornex Co., Ltd. ((A2) component) Carboxyl group-containing photosensitive resin A: Acid-modified cresol novolac type epoxy acrylate resin with added glycidyl methacrylate (solids content: 65% by mass, solvent: diethylene glycol monoethyl ether acetate 17.5% by mass, petroleum naphtha 17.5% by mass), trade name "Lipoxy SP-4785", manufactured by Resonaq Corporation. Carboxyl group-containing photosensitive resin B: Acid-modified biphenyl aralkyl type epoxy acrylate (solids content: 65% by mass, solvent: diethylene glycol monoethyl ether acetate 35% by mass), trade name "ZCR-1601H", manufactured by Nippon Kayaku Co., Ltd. ((B) component) Photopolymerization initiator A: Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, trade name "Omnirad 819", manufactured by Siber Hegner Japan. Photopolymerization initiator B: 2,4,6-trimethylbenzoyldiphenylphosphine oxide, trade name "Omnirad TPO", manufactured by BASF. Photopolymerization initiator C: 1-(4-morpholinophenyl)-2-(dimethylamino)-2-(4-methylbenzyl)-1-butanone, trade name "Omnirad 379EG", manufactured by BASF. Photopolymerization initiator D: (9-ethyl-6-nitro-9H-carbazole-3-yl)(4-((1-methoxypropan-2-yl)oxy)-2-methylphenyl)methanone O-acetyloxyMu ((C) component) Reactive diluent A: Caprolactone-modified acrylate (molecular weight: 1263), trade name "DPCA-60", Nippon Kayaku Co., Ltd. Reactive diluent B: Caprolactone-modified acrylate (molecular weight: 1948), trade name "DPCA-120", Nippon Kayaku Co., Ltd. ((D) component) Epoxy compound A: Cresol novolac type epoxy resin, trade name "N-860", manufactured by DIC Corporation. Epoxy compound B: Biphenyl novolac 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 ingredients) Epoxy acrylate: Cresol novolac type epoxy acrylate (solids content: 65%, solvent: diethylene glycol monoethyl ether acetate 35% by mass), trade name "SP-4621BC", manufactured by Resonaq Corporation. Thermosetting catalyst A: Melamine, manufactured by Nissan Chemical Corporation 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 Sunapro Co., Ltd. Coloring agent A: Acetylene black, manufactured by Denka Co., Ltd. Coloring agent B: Phthalocyanine blue, manufactured by DIC Corporation. Antifoaming agent: Product name "Floren AC-2300C", manufactured by Kyoeisha Chemical Co., Ltd. Flame retardant A: Organic phosphate, product name "Exolit OP-935", manufactured by BASF. Flame retardant B: Aluminum hydroxide, product 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 Seika Kogyo Co., Ltd. Ion Catcher: Product name "IXE-100", manufactured by Toagosei Co., Ltd. Non-reactive diluent: Diethylene glycol monomethyl ether acetate, trade name "EDGAC", manufactured by Sanyo Chemical Industries, Ltd.

[0052] [Preparation Example 1] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and reflux tubing, 129 g of dipropylene glycol monomethyl ether (hereinafter also referred to as DPM) was added. After raising the temperature 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, hereinafter also referred to as PEMA), and 5 g of dimethyl 2,2'-azobis(2-methylpropionate) (V-60, manufactured by Wako Pure Chemical Industries) were added dropwise over approximately 1 hour. The mixture was then stirred at 120°C for 3 hours. Next, the contents of the flask were... After lowering the temperature to 100°C, 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 to the flask while a mixture of air and nitrogen (air volume to nitrogen volume ratio of 1:2) was passed through at a rate of 200 mL / min. The reaction was then carried out at 100°C for 5 hours, and then continued at 115°C until the acid value decreased completely to prepare a DPM solution (carboxyl group-containing photosensitive copolymer resin A) containing approximately 49% by mass of copolymer resin 1. The weight-average molecular weight of copolymer resin 1 was approximately 19000 (polystyrene equivalent), and the acid value of the DPM solution was 45.6 mgKOH / g.

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

[0054] [Example 1] 43 parts by mass of carboxyl group-containing photosensitive copolymer resin A, 0.6 parts by mass of photopolymerization initiator A, 1 part by mass of photopolymerization initiator 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 parts by mass of colorant A, 0.2 parts 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 placed in a container, pre-mixed with a stirrer, and then mixed and dispersed at room temperature using a three-roll roller 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 resulting photosensitive resin composition was applied by screen printing to a dry film thickness of 20-23 μm to obtain a coated substrate. After application, pre-drying was performed in a box oven at 80°C for 20 minutes. After pre-drying, the coating film was exposed to light using an exposure device (ORC's direct exposure device "Mms604") at an exposure dose of 400 mJ / cm². 2 Exposure was performed under the following conditions. After exposure, development was carried out using a 1% by mass sodium carbonate aqueous solution at a development temperature of 30°C for 60 seconds. Subsequently, 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 prepared.

[0055] [Examples 2-10] 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 results shown in Table 1. [Comparative Examples 1-4] 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 results shown in Table 1.

[0056] [Evaluation of photosensitive resin compositions] The photosensitive resin composition was evaluated (sensitivity evaluation, gloss value, adhesion, and electrical insulation) using the following method. The results are shown in Table 1. (1) Sensitivity evaluation After pre-drying the coated substrate at 80°C for 20 minutes, a sensitivity measurement step tablet (Kodak 21-step) was placed on the substrate, and a measurement of 100 mJ / cm² was taken. 2 , 200 mJ / cm 2 300 mJ / cm² 2 , and 400 mJ / cm 2 Exposure was performed under each of the following conditions, and a 1% sodium carbonate aqueous solution was used, with a density of 2.0 kg / cm³. 2 The area of ​​exposure that remains unremoved after developing for 60 seconds at a given spray pressure is represented by a number (step count). Then, the exposure amount that results in 8 steps was determined. (2) Gross value The cured coating film of the evaluation substrate was measured for 60-degree gloss (gloss value) using Microtrigloss (manufactured by Bic Chemie Japan Co., Ltd.) to evaluate its matte appearance. The 60-degree gloss value was expressed with two significant figures of the average value, rounded to the third digit. (3) Adhesion Adhesion tests were conducted on the cured coating film of the evaluation substrate in accordance with JIS K5600-5-6. The adhesion was then evaluated according to the following criteria. ◎: No peeling. ○: The peeling area is less than 5%. △: The peeling area is 5% or more but less than 50%. ×: The peeling area is 50% or more. (4) Electrical insulation Under the same conditions as 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 comprising (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) a reactive diluent, and (D) an epoxy compound, The aforementioned component (A) contains only (A1) a carboxyl group-containing photosensitive copolymer resin, The photosensitive resin composition does not contain an extender pigment, or the amount of the extender pigment is 20 parts by mass or less per 100 parts by mass of component (A). The aforementioned component (B) contains 1-(4-morpholinophenyl)-2-(dimethylamino)-2-(4-methylbenzyl)-1-butanone and (9-ethyl-6-nitro-9H-carbazole-3-yl)(4-((1-methoxypropan-2-yl)oxy)-2-methylphenyl)methanone O-acetyloxime, The photosensitive resin composition is applied to a dry film thickness of 20 to 23 μm, pre-dried in a box oven at 80°C for 20 minutes, and exposed to an exposure dose of 400 mJ / cm². ２ The material is exposed to light under the specified conditions, developed using a 1% by mass sodium carbonate aqueous solution at a development temperature of 30°C for 60 seconds, and then post-cured in a box furnace at 150°C for 60 minutes to obtain a cured product. When the gloss value of this cured product at 60°C is measured, the gloss value is 40 or less. Photosensitive resin composition.

2. In the photosensitive resin composition according to claim 1, The weight-average molecular weight of component (A1) is 20,000 or more. Photosensitive resin composition.

3. In the photosensitive resin composition according to claim 1 or claim 2, The solid content acid value of component (A1) is 90 mg KOH / g or more. Photosensitive resin composition.

4. In the photosensitive resin composition according to claim 1 or claim 2, Furthermore, it contains cresol novolac type epoxy acrylate, Photosensitive resin composition.

5. In the photosensitive resin composition according to claim 1 or claim 2, Furthermore, it contains N'-[3-[[[(dimethylamino)carbonyl]amino]methyl]-3,5,5-trimethylcyclohexyl]-N,N-dimethylurea, Photosensitive resin composition.

6. In the photosensitive resin composition according to claim 1 or claim 2, The cured product of the aforementioned photosensitive resin composition is black in color. Photosensitive resin composition.

7. The present invention comprises a solder resist film made from a cured product of the photosensitive resin composition according to claim 1 or claim 2. Printed circuit board.

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