JP2018097036A - Photosensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition from which a cured coating film can be formed that has excellent sensitivity and an excellent appearance and can prevent sagging even when the photosensitive resin composition is applied to be thick by use of a spray coating method.SOLUTION: (The photosensitive resin composition comprises: (A) a carboxyl group-containing photosensitive resin that is a reaction product obtained by allowing a glycidyl compound having a radically polymerizable unsaturated group and an epoxy group to react with a carboxyl group of a polybasic acid-modified radically polymerizable unsaturated monocarboxylate epoxy resin which is a compound obtained by allowing a polybasic acid or its anhydride to react with a reaction product between a polyfunctional epoxy resin having at least two epoxy groups in one molecule and a radically polymerizable unsaturated monocarboxylic acid; (B) a photopolymerization initiator; (C) a reactive diluent; (D) an epoxy compound; (E) bentonite treated with a quaternary ammonium salt represented by general formula (I): [RRRR-N]X, where R, R, R, Reach independently represent a saturated aliphatic hydrocarbon group having 1 to 25 carbon atoms or an unsaturated aliphatic hydrocarbon group having 2 to 25 carbon atoms, and X represents a halogen selected from the group consisting of fluorine, chlorine, bromine and iodine; and (F) hydrophobic silica. The (F) hydrophobic silica is included by from 4.5 parts by mass to 20 parts by mass with respect to 100 parts by mass of the (A) carboxyl group-containing photosensitive resin.SELECTED DRAWING: None

Description

  The present invention relates to a photosensitive resin composition suitable for a coating material for coating a coating material, for example, a conductor circuit pattern formed on a substrate such as a printed wiring board, a cured product obtained by curing the photosensitive resin composition, and the cured product. The present invention relates to a coated printed wiring board.

  A printed wiring board such as a flexible printed wiring board or a rigid wiring board is used for forming a conductive circuit pattern on a substrate and mounting an electronic component on the soldering land of the pattern by soldering. The circuit part except for is covered with a protective film (for example, a solder resist film). This prevents solder from adhering to unnecessary parts when soldering electronic components to a printed wiring board, and prevents circuit conductors from being directly exposed to air and being corroded by oxidation or humidity. To do.

  Further, the conductor forming the conductor circuit pattern may be designed to be thicker (35 μm or more, for example, 50 to 100 μm) than the conventional general-purpose thickness (about 10 to 25 μm). When a protective film such as a solder resist film is formed on a printed wiring board having a thick conductor circuit, it is necessary to increase the thickness of the protective film accordingly (for example, a thickness of 60 to 110 μm). It is necessary to apply a thick resin composition (for example, a thickness of 70 to 150 μm).

  Therefore, a printed wiring board has been proposed in which the photocurable solder resist layer has a laminated structure composed of a lower layer solder resist and an upper layer solder resist (Patent Document 1).

  However, as in Patent Document 1, if the photosensitive resin composition that is the raw material of the protective film is applied thickly, from the thickness of the coating film, ultraviolet rays are difficult to reach in the deep part of the coating film when exposed to ultraviolet rays. There was a problem that the sensitivity of the coating film (especially the sensitivity near the bottom of the coating film) was not sufficient, and high resolution and good line shape could not be obtained.

  From the viewpoint of workability, the photosensitive resin composition may be applied to a printed wiring board by a spray coating method. However, when the photosensitive resin composition is applied thick as described above by the spray coating method, there is a problem that the coating film is sagged or a good coating film appearance cannot be obtained.

JP 2010-129575 A

  In view of the above circumstances, the object of the present invention is to provide a cured coating film that has excellent sensitivity, can prevent sagging, and is excellent in appearance even with a photosensitive resin composition that has been applied thickly using a spray coating method. And a wiring board such as a printed wiring board having a photocured film of the photosensitive resin composition.

Aspects of the present invention are: (A) a radical polymerizable unsaturated monocarboxylic oxide epoxy which is a reaction product of a polyfunctional epoxy resin having two or more epoxy groups in one molecule and a radical polymerizable unsaturated monocarboxylic acid Glycidyl having a radical polymerizable unsaturated group and an epoxy group on the carboxyl group of a polybasic acid-modified radical polymerizable unsaturated monocarboxylic oxide epoxy resin, which is a compound in which a hydroxyl group of the resin is reacted with a polybasic acid or its anhydride A carboxyl group-containing photosensitive resin (hereinafter, also referred to as “(A) component carboxyl group-containing photosensitive resin”), (B) a photopolymerization initiator, and (C ) A reactive diluent, (D) an epoxy compound, (E) the following general formula (I)
[Chemical 1]
[R ¹ R ² R ³ R ⁴ —N] ⁺ X ⁻ (I)
(Wherein R ¹ , R ² , R ³ and R ⁴ are each independently a saturated aliphatic hydrocarbon group having 1 to 25 carbon atoms or an unsaturated aliphatic hydrocarbon group having 2 to 25 carbon atoms, X is , A bentonite treated with a quaternary ammonium salt represented by fluorine, chlorine, bromine and iodine selected from the group consisting of iodine (hereinafter, treated with a quaternary ammonium salt of component (E) And (F) hydrophobic silica, and the (F) hydrophobic silica is based on 100 parts by mass of the carboxyl group-containing photosensitive resin of the component (A). It is a photosensitive resin composition containing 4.5 parts by mass to 20 parts by mass.

  In the said aspect, the carboxyl group-containing photosensitive resin of (A) component has a radical polymerizable unsaturated group and an epoxy group in addition to the carboxyl group of the polybasic acid-modified radical polymerizable unsaturated monocarboxylic oxide epoxy resin. Since it has a chemical structure in which a glycidyl compound has reacted, it has the characteristics of improved photosensitivity. Moreover, "100 mass parts of carboxyl group-containing photosensitive resin" means the mass part of solid content of carboxyl group-containing photosensitive resin.

  In the aspect of the present invention, the bentonite treated with the quaternary ammonium salt of the component (E) is 5.0 parts by mass to 20 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin of the component (A). It is a photosensitive resin composition containing a part.

  In the aspect of the present invention, the hydrophobic silica (F) contains 5.5 parts by mass to 13.5 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin of the component (A). The bentonite treated with the quaternary ammonium salt of the component is a photosensitive resin composition containing 8.0 parts by mass to 18 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin of the component (A). is there.

  In the aspect of the present invention, the mass of bentonite treated with the quaternary ammonium salt of the component (E): the mass of the hydrophobic silica (F) is in the range of 1.0: 0.30 to 3.0. It is a certain photosensitive resin composition.

  An aspect of the present invention is a photosensitive resin composition in which the (F) hydrophobic silica is silica modified with an alkylsilyl group.

  An aspect of the present invention is a photosensitive resin composition in which the quaternary ammonium salt is a distearyldimethylammonium salt.

  The aspect of this invention is the photocured material of the said photosensitive resin composition.

  An aspect of the present invention is a wiring board having a photocured film of the photosensitive resin composition.

  According to the aspect of the present invention, the carboxyl group-containing photosensitive resin (A) having the above-described improved photosensitivity is used as the carboxyl group-containing photosensitive resin. By blending bentonite treated with an ammonium salt and 4.5 parts by mass to 20 parts by mass of (F) hydrophobic silica with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin of component (A), It is possible to obtain a photosensitive resin composition that can form a cured coating film that has excellent sensitivity, can prevent sagging, and has an excellent appearance, even if it is a photosensitive resin composition that is thickly applied by a spray coating method. it can.

  According to the aspect of the present invention, the bentonite treated with the quaternary ammonium salt of the component (E) is 5.0 parts by mass to 20 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin of the component (A). By blending, even a photosensitive resin composition thickly applied by a spray coating method can surely prevent sagging of the coating film without damaging excellent sensitivity, and the appearance of the cured coating film It can be improved further.

  According to the aspect of the present invention, (F) 5.5 to 13.5 parts by mass of hydrophobic silica and (E) of component (E) with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin of component (A). By containing 8.0 parts by weight to 18 parts by weight of bentonite treated with a quaternary ammonium salt, even a photosensitive resin composition thickly applied by a spray coating method may impair excellent sensitivity. In addition, the prevention of sagging and the appearance of the coating film can be improved in a well-balanced manner.

  According to the aspect of the present invention, the mass of bentonite treated with the quaternary ammonium salt of component (E): (F) the mass of hydrophobic silica is 1.0: 0.30-3.0 Even if it is the photosensitive resin composition apply | coated thickly by the spray coating method, the photosensitive resin composition which can prevent dripping reliably and can form the cured coating film excellent in the external appearance can be obtained.

  According to the aspect of the present invention, since the (F) hydrophobic silica is a silica modified with an alkylsilyl group, even if it is a photosensitive resin composition thickly applied by spray coating, It is possible to reliably prevent the coating from sagging.

  According to the aspect of the present invention, the quaternary ammonium salt is a distearyldimethylammonium salt, thereby obtaining a photosensitive resin composition that can more reliably prevent sagging and form a cured coating film having an excellent appearance. be able to.

Next, the photosensitive resin composition of the present invention will be described below. The photosensitive resin composition of the present invention comprises (A) a radical polymerizable unsaturated which is a reaction product of a polyfunctional epoxy resin having two or more epoxy groups in one molecule and a radical polymerizable unsaturated monocarboxylic acid. A radical polymerizable unsaturated group and an epoxy group are added to a carboxyl group of a polybasic acid-modified radical polymerizable unsaturated monocarboxylic oxide epoxy resin, which is a compound obtained by reacting a hydroxyl group of a monocarboxylic oxide epoxy resin with a polybasic acid or an anhydride thereof. A carboxyl group-containing photosensitive resin, which is a reaction product obtained by reaction of a glycidyl compound having, and (B) a photopolymerization initiator, (C) a reactive diluent, (D) an epoxy compound, and (E) Formula (I)
[Chemical 1]
[R ¹ R ² R ³ R ⁴ —N] ⁺ X ⁻ (I)
(Wherein R ¹ , R ² , R ³ and R ⁴ are each independently a saturated aliphatic hydrocarbon group having 1 to 25 carbon atoms or an unsaturated aliphatic hydrocarbon group having 2 to 25 carbon atoms, X is Represents a halogen selected from the group consisting of fluorine, chlorine, bromine and iodine.) Bentonite treated with a quaternary ammonium salt represented by: (F) hydrophobic silica, and (F ) Hydrophobic silica is contained in an amount of 4.5 to 20 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin as the component (A).

(A) Component carboxyl group-containing photosensitive resin (A) Component carboxyl group-containing photosensitive resin is an acrylic resin in at least part of the epoxy group of a polyfunctional epoxy resin having two or more epoxy groups in one molecule. Radical polymerizable unsaturated monocarboxylic acid such as epoxy (meth) acrylate by reacting with radical polymerizable unsaturated monocarboxylic acid such as acid or methacrylic acid (hereinafter sometimes referred to as “(meth) acrylic acid”) An epoxy resin is obtained, and a polybasic acid-modified epoxy (meth) acrylate or other polybasic acid-modified radical polymerizability is obtained by reacting a polybasic acid or its anhydride with the hydroxyl group of the generated radical polymerizable unsaturated monocarboxylic oxide epoxy resin. An unsaturated monocarboxylic oxide epoxy resin was obtained, and the resulting polybasic acid-modified radical polymerizable unsaturated monocarboxylic oxide epoxy resin was obtained. It is a resin obtained by reacting a part of a carboxyl group with a glycidyl compound having one or more radically polymerizable unsaturated groups and an epoxy group.

  The component (A) carboxyl group-containing photosensitive resin blended in the photosensitive resin composition of the present invention is obtained by reacting a glycidyl compound with the carboxyl group of a polybasic acid-modified radical polymerizable unsaturated monocarboxylic oxide epoxy resin. In addition, since the radical polymerizable unsaturated group is introduced into the side chain of the polybasic acid-modified radical polymerizable unsaturated monocarboxylic oxide epoxy resin, the polybasic acid-modified radical polymerizable unsaturated monocarboxylic oxide epoxy resin and In comparison, it has excellent photosensitivity.

  Therefore, a thick protective film (for example, 60 to 110 μm) is formed on a printed wiring board designed with a thick conductor (thickness of 35 μm or more, for example, 50 to 100 μm). Therefore, even if the photosensitive resin composition is applied thick (for example, 70 to 150 μm in thickness), the sensitivity of the coating film (especially the sensitivity near the bottom of the coating film) is excellent, so high resolution A cured coating film having a good line shape can be obtained.

  Any polyfunctional epoxy resin can be used as long as it is a bifunctional or higher functional epoxy resin. Although the epoxy equivalent of a polyfunctional epoxy resin is not specifically limited, 3000 or less are preferable, 2000 or less are more preferable, and 100-500 are especially preferable. Examples of the polyfunctional epoxy resin include biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, rubber modified epoxy resin such as silicone modified epoxy resin, ε-caprolactone modified epoxy resin, bisphenol A type, bisphenol. Phenolic novolak type epoxy resin such as F type, bisphenol AD type, cresol novolac type epoxy resin such as о-cresol novolak type, bisphenol A novolak type epoxy resin, cyclic aliphatic polyfunctional epoxy resin, glycidyl ester type polyfunctional epoxy Resin, glycidylamine type polyfunctional epoxy resin, heterocyclic polyfunctional epoxy resin, bisphenol modified novolac type epoxy resin, polyfunctional modified novolak type epoxy resin, phenols and phenol And a condensate type epoxy resin with an aromatic aldehyde having a functional hydroxyl group. Moreover, you may use what introduce | transduced halogen atoms, such as Br and Cl, into these resin. These polyfunctional epoxy resins may be used alone or in combination of two or more.

  The radically polymerizable unsaturated monocarboxylic acid is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, and acrylic acid and methacrylic acid are preferable. These radically polymerizable unsaturated monocarboxylic acids may be used alone or in combination of two or more.

  The reaction method of the polyfunctional epoxy resin and the radically polymerizable unsaturated monocarboxylic acid is not particularly limited. For example, the polyfunctional epoxy resin and the radically polymerizable unsaturated monocarboxylic acid are heated in a suitable diluent. Can be reacted.

  The polybasic acid or polybasic acid anhydride is for reacting with the hydroxyl group produced by the reaction of the polyfunctional epoxy resin and the radically polymerizable unsaturated monocarboxylic acid to introduce a free carboxyl group into the resin. is there. The polybasic acid or its anhydride is not particularly limited, and either saturated or unsaturated can be used. Polybasic acids include, for example, 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, methylhexahydro Examples include phthalic 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 alone or in combination of two or more.

  The glycidyl compound having one or more radically polymerizable unsaturated groups and an epoxy group is not particularly limited. For example, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, pentaerythritol triacrylate monoglycidyl ether, pentaerythritol trimethacrylate mono A glycidyl ether etc. are mentioned. In addition, you may have multiple glycidyl groups in 1 molecule. The above-mentioned compound having one or more radically polymerizable unsaturated groups and an epoxy group may be used alone or in combination of two or more.

  The acid value of the carboxyl group-containing photosensitive resin as the component (A) is not particularly limited, but the lower limit is preferably 30 mgKOH / g, particularly preferably 40 mgKOH / g, from the viewpoint of reliable alkali development. On the other hand, the upper limit of the acid value is preferably 200 mgKOH / g from the viewpoint of preventing dissolution of the exposed area with an alkali developer, and particularly preferably 150 mgKOH / g from the viewpoint of preventing moisture from being cured and preventing deterioration of electrical characteristics.

  Further, the mass average molecular weight of the carboxyl group-containing photosensitive resin as the component (A) is not particularly limited, but the lower limit is preferably 3000 and particularly preferably 5000 from the viewpoint of toughness and dryness to touch of the cured product. . On the other hand, the upper limit value of the mass average molecular weight is preferably 200000, particularly preferably 50000, from the viewpoint of smooth alkali developability.

(B) Photopolymerization initiator The photopolymerization initiator is not particularly limited as long as it is generally used, and any of them can be used. Specifically, for example, ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] -1- (0-acetyloxime), phenylbis (2,4,4) 6-trimethylbenzoyl) phosphine oxide, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2 , 2-Diethoxy-2-phenylacetophenone, 2-methyl-4 '-(methylthio) -2-morpholinopropiophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl Keto 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethyl Anthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal P-dimethylaminobenzoic acid ethyl ester and the like. These may be used alone or in combination of two or more.

  Content of a photoinitiator is not specifically limited, For example, 5-20 mass parts is preferable with respect to 100 mass parts of carboxyl group-containing photosensitive resin (solid content, hereafter the same) of (A) component.

(C) Reactive Diluent The reactive diluent is, for example, a photopolymerizable monomer and is a compound having at least one polymerizable double bond per molecule, preferably at least two polymerizable double bonds per molecule. The reactive diluent is used to obtain a cured product having sufficient acid resistance, heat resistance, alkali resistance, etc., by sufficiently photocuring the photosensitive resin composition.

  The reactive diluent is not particularly limited as long as it is the above compound. For example, 2-hydroxyethyl methacrylate, phenoxyethyl methacrylate, diethylene glycol monomethacrylate, 2-hydroxy-3-phenoxypropyl 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 neo Pentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified di (meth) acrylate Rate, allylated cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tri (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, dipentaerythritol hexa (Meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, urethane (meth) acrylate Etc. The. These may be used alone or in combination of two or more.

  Content of a reactive diluent is not specifically limited, For example, 2.0-200 mass parts is preferable with respect to 100 mass parts of carboxyl group-containing photosensitive resin of (A) component, and 10-100 mass parts is preferable. Particularly preferred.

(D) Epoxy compound An epoxy compound is for obtaining the hardened | cured material of sufficient intensity | strength by raising the crosslinking density of hardened | cured material, For example, an epoxy resin can be mentioned. Examples of the epoxy resin include biphenyl type epoxy resin, bisphenol A type epoxy resin, novolak type epoxy resin (phenol novolak type epoxy resin, o-cresol novolak type epoxy resin, p-tert-butylphenol novolak type, etc.), bisphenol F, and the like. Bisphenol F-type and bisphenol S-type epoxy resins obtained by reacting bisphenol S with epichlorohydrin, alicyclic epoxy resins having cyclohexene oxide groups, tricyclodecane oxide groups, cyclopentene oxide groups, and the like, tris (2,3- Epoxypropyl) isocyanurate, triglycidyl isocyanurate having a triazine ring such as triglycidyltris (2-hydroxyethyl) isocyanurate, dicyclopentadi Emission type epoxy resins, adamantane type epoxy resin. These compounds may be used alone or in combination of two or more.

  The content of the epoxy compound is not particularly limited, and is, for example, 10 to 200 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin of the component (A) from the viewpoint of obtaining a coating film having sufficient strength after curing. Is preferable, and 20-100 mass parts is especially preferable.

Bentonite treated with quaternary ammonium salt of component (E) By blending bentonite treated with quaternary ammonium salt of component (E) together with (F) hydrophobic silica described later, a spray coating method can be applied. Even a thick photosensitive resin composition can prevent sagging and form a cured coating film having an excellent appearance.

The bentonite treated with the quaternary ammonium salt of component (E) has the following general formula (I)
[Chemical 1]
[R ¹ R ² R ³ R ⁴ —N] ⁺ X ⁻ (I)
(Wherein R ¹ , R ² , R ³ and R ⁴ are each independently a saturated aliphatic hydrocarbon group having 1 to 25 carbon atoms or an unsaturated aliphatic hydrocarbon group having 2 to 25 carbon atoms, X is Represents a halogen selected from the group consisting of fluorine, chlorine, bromine and iodine.) And bentonite treated with a quaternary ammonium salt.

^R 1 of the quaternary ammonium ^salt, R ^2, R 3, ^{R 4} are each, if unsaturated aliphatic hydrocarbon radical of a saturated aliphatic hydrocarbon group, or 2 to 25 carbon atoms having 1 to 25 carbon atoms Although not particularly limited, a saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms and a saturated aliphatic hydrocarbon having 7 to 22 carbon atoms from the viewpoint of reliably preventing sagging and forming a cured coating film having an excellent appearance. A quaternary ammonium salt having a group is preferable, and a quaternary ammonium salt having a saturated aliphatic hydrocarbon group having 1 to 2 carbon atoms and a saturated aliphatic hydrocarbon group having 15 to 20 carbon atoms is particularly preferable.

  Specific examples of the quaternary ammonium salts include distearyl dimethyl ammonium salts such as distearyl dimethyl ammonium chloride and distearyl dimethyl ammonium bromide, stearyl trimethyl ammonium salts such as stearyl trimethyl ammonium chloride and stearyl trimethyl ammonium bromide, and lauryl chloride. Lauryltrimethylammonium salts such as trimethylammonium, lauryltrimethylammonium bromide, behenyltrimethylammonium chloride such as behenyltrimethylammonium chloride, dioctyldimethylammonium chloride such as dioctyldimethylammonium chloride, dioctyldimethylammonium bromide, etc. Can be mentioned. Of these, distearyldimethylammonium salts such as distearyldimethylammonium chloride and distearyldimethylammonium bromide are preferable from the viewpoint of more reliably preventing sagging and forming a cured coating film having an excellent appearance.

  (E) Content of the bentonite processed with the quaternary ammonium salt of a component is not specifically limited, For example, the lower limit is with respect to 100 mass parts of carboxyl group-containing photosensitive resin of (A) component, The amount is preferably 5.0 parts by mass from the viewpoint of reliably preventing sagging, and is particularly preferably 8.0 parts by mass from the viewpoint of improving the coverability in the vicinity of a conductor such as a copper foil. In addition, the upper limit is 20 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin of the component (A) in order to easily maintain the appearance of an excellent cured coating film while facilitating spray coating. Preferably, 18 parts by mass is particularly preferable.

(F) Hydrophobic silica By blending (F) hydrophobic silica with bentonite treated with the quaternary ammonium salt of component (E) described above, a photosensitive resin composition applied thickly by spray coating. Even if it is a thing, dripping can be prevented and the cured coating film excellent in the external appearance can be formed.

  The hydrophobic silica is, for example, silica obtained by hydrophobizing the surface of hydrophilic silica having a silanol group with a hydrophobic compound, and is a spherical or substantially spherical fine particle. As the hydrophobic silica, for example, the surface of fine silica such as fumed silica or silica airgel obtained by flame hydrolysis of silicon tetrachloride is a hydrophobic compound, and an organosilicon compound such as a silane compound or a siloxane compound. And hydrophobized. Examples of the organic silicon compound that is the hydrophobic compound include methacryloxysilane, methylchlorosilane, dimethyldichlorosilane, hexamethyldisilazane, dimethylsiloxane, trimethoxyoctylsilane, methacrylsilane, and acrylic silane. Of these, hydrophobic silica whose surface is modified with an alkylsilyl group is preferable from the viewpoint of preventing the coating from sagging more reliably even with a photosensitive resin composition applied thickly by a spray coating method. .

The primary particle diameter of the hydrophobic silica is not particularly limited, but is preferably 3 to 100 nm, particularly preferably 5 to 50 nm from the viewpoint of dispersibility. Moreover, the BET specific surface area of hydrophobic silica is not particularly limited, but for example, 50 to 500 m ² / g is preferable.

  Content of hydrophobic silica is 4.5 mass parts-20 mass parts with respect to 100 mass parts of carboxyl group-containing photosensitive resin of (A) component. When the photosensitive resin composition of the present invention is thickly applied by a spray coating method, the amount is less than 4.5 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin of component (A). If it exceeds 20 parts by mass, it may not be possible to obtain an excellent appearance of the cured coating film by the spray coating method. Moreover, the lower limit of the content of hydrophobic silica is preferably 5.5 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin of component (A), and the upper limit of the content of hydrophobic silica is ( 13.5 parts by mass is preferable with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin as component A).

  In addition, even if the photosensitive resin composition is thickly applied by spray coating, the carboxyl (A) component is used because it prevents dripping and improves the appearance of the coating film in a well-balanced manner without impairing excellent sensitivity. Bentonite containing 5.5 parts by weight to 13.5 parts by weight of hydrophobic silica and 100 parts by weight of the group-containing photosensitive resin and treated with the quaternary ammonium salt of component (E) is 8.0. It is preferable to contain mass parts-18 mass parts.

  The ratio of the mass of bentonite treated with the quaternary ammonium salt of component (E) and the mass of hydrophobic silica is not particularly limited, but the mass of bentonite treated with the quaternary ammonium salt of component (E): Hydrophobic silica has a mass of 1.0 from the point that even a photosensitive resin composition coated thick by spray coating can reliably prevent sagging and form a cured coating film having an excellent appearance. : 0.30 to 3.0 is preferable, 1.0: 0.50 to 2.5 is more preferable, and 1.0: 0.80 to 1.5 is particularly preferable.

  In the photosensitive resin composition of the present invention, in addition to the above components (A) to (F), various components, for example, non-reactive dilutions such as colorants, various additives, organic solvents, etc. An agent, a filler, etc. can be mix | blended.

  The colorant is not particularly limited. For example, as a white colorant, an inorganic pigment such as titanium oxide, as a colorant other than white, a green colorant such as phthalocyanine green, a blue colorant such as phthalocyanine blue, an anthraquinone series Examples thereof include organic pigments such as yellow colorants such as inorganic pigments, and inorganic pigments such as black colorants such as carbon black.

  Various additives include, for example, silicone-based, hydrocarbon-based and acrylic-based antifoaming agents, dispersants, silane-based, titanate-based and alumina-based coupling agents, boron trifluoride-amine complex, dicyandiamide ( DICY) and derivatives thereof, organic acid hydrazide, diaminomaleonitrile (DAMN) and derivatives thereof, guanamine and derivatives thereof, melamine and derivatives thereof, amine imide (AI) and latent curing agents such as polyamines, acetylacetonate Zn and acetylacetate Metal salts of acetylacetone such as nato Cr, enamines, tin octylates, quaternary sulfonium salts, imidazoles such as triphenylphosphine and 2-mercaptobenzimidazole, imidazolium salts and thermosetting accelerators such as triethanolamine borate, Poly Etc. thixotropic agents such as carboxylic acid amide can be mentioned.

  The filler contributes to increasing the physical strength of the coating film of the photosensitive resin composition, and examples thereof include talc, barium sulfate, silica, alumina, aluminum hydroxide, and mica.

  The non-reactive diluent is for adjusting the drying property and coating viscosity of the photosensitive resin composition, and examples thereof include an organic solvent. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether , Glycol ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, cellosolve acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene Glycol monomethyl ether acetate and the above Esters such as esters of calls ethers; ethanol, can be mentioned propanol, ethylene glycol, and alcohols such as propylene glycol.

  Although the manufacturing method of the above-mentioned photosensitive resin composition is not limited to a specific method, For example, after mix | blending each said component by a predetermined ratio, it can mix and disperse | distribute with a three roll at room temperature. Moreover, you may pre-mix with a stirrer before the said mixing dispersion | distribution as needed.

  Next, the usage example of the photosensitive resin composition of this invention is demonstrated. Here, a method of applying the photosensitive resin composition of the present invention as an insulating protective film (for example, a solder resist film) of a printed wiring board will be described as an example.

  The photosensitive resin composition of the present invention obtained as described above is a substrate having a circuit pattern (for example, a copper foil thickness of 50 μm or more) formed by etching a copper foil, for example. When a desired thickness, for example, a DRY film thickness of 60 μm or more is applied on the wiring board by spray coating (spray coater method), a coating film is formed by coating with a wet film thickness of 70 μm or more. Next, when the non-reactive diluent such as an organic solvent is contained in the photosensitive resin composition, in order to volatilize the non-reactive diluent, the temperature is about 60 to 80 ° C. for 15 to 60 minutes. Pre-drying is performed to a certain degree to form a tack-free coating film.

  Next, a negative film (photomask) having a light-transmitting pattern other than the circuit pattern land is brought into close contact with the pre-dried coating film, and ultraviolet light (for example, in a wavelength range of 300 to 400 nm) is formed thereon. ). Then, the coating film is developed by removing the non-exposed areas corresponding to the lands with a dilute alkaline aqueous solution. As the developing method, a spray method, a shower method, or the like is used, and examples of the diluted alkaline aqueous solution to be used include 0.5 to 5% by mass of an aqueous sodium carbonate solution. Next, by performing post-cure for 20 to 80 minutes with a hot air circulation dryer or the like at 130 to 170 ° C., a desired insulating protective film such as a solder resist film can be formed on the printed wiring board.

  In addition, as a coating method, instead of spray coating (spray coater method), other known coating methods such as screen printing, bar coater, applicator, blade coater, knife coater, roll coater, and gravure coater may be used. Good.

  Next, examples of the present invention will be described, but the present invention is not limited to these examples as long as it does not exceed the gist thereof.

Examples 1-7, Comparative Examples 1-7
The components shown in Table 1 below are blended in the proportions shown in Table 1 below, mixed and dispersed at room temperature using three rolls, and used in Examples 1 to 7 and Comparative Examples 1 to 7. A resin composition was prepared. And the prepared photosensitive resin composition was applied as follows and the test piece was produced. The numbers in Table 1 below indicate parts by mass. Moreover, the blank in Table 1 below means no blending.

  The details of each component in Table 1 are as follows.

(A) Component carboxyl group-containing photosensitive resin 250 parts by mass of carbitol acetate, 220 parts by mass of cresol novolac type epoxy resin (manufactured by Sumitomo Chemical Co., Ltd., ESCN-220, epoxy equivalent 220) and 72 parts by mass of acrylic acid Was dissolved and reacted under reflux to obtain a cresol novolac epoxy acrylate. Next, 138.6 parts by mass of hexahydrophthalic anhydride was added to the obtained cresol novolac type epoxy acrylate and reacted under reflux until the acid value reached a theoretical value, and then 56.8 parts by mass of glycidyl methacrylate was added. The reaction was further performed to obtain a carboxyl group-containing photosensitive resin synthetic resin (A-1) as component (A) having a solid content of 65% by mass.

(B) Photopolymerization initiator / Irgacure 907: BASF Japan K.K.
・ KAYACURE DETX: Nippon Kayaku Co., Ltd.
(C) Reactive diluent DPHA: Toagosei Co., Ltd.
(D) Epoxy compound / Epicoat 828, YX-4000K: Mitsubishi Chemical Corporation

(E) Bentonite thixogel treated with component quaternary ammonium salt VP: united catalyst (F) Hydrophobic silica Aerosil R974: Surface modified with dimethylsilyl group, Nippon Aerosil Co., Ltd.

Filler Barium sulfate B-34: Sakai Chemical Industry Co., Ltd.
・ FH105: Fuji Talc Co., Ltd.
Colorant, Fast Gen Green: DIC

Various additives and melamine: Nissan Chemical Industries, Ltd.
-DICY-7: Japan Epoxy Resin Co., Ltd.
・ Antage MB: Kawaguchi Chemical Industry Co., Ltd.
・ Disperbyk-103, BYK-410: Big Chemie Japan Co., Ltd.
Non-reactive diluent / PMA: Sanyo Chemicals Co., Ltd.

(A) Carboxy group-containing photosensitive resin other than component, lipoxy SP-4621: Showa Denko K.K.
(E) Bentonite thixogel treated with quaternary ammonium salt other than component LG: united catalyst hydrophilic silica Aerosil # 380: Nippon Aerosil Co., Ltd.

Test piece production process board: Printed wiring board (glass epoxy board “FR-4”, board thickness 1.6 mm, conductor (Cu foil) thickness 18 to 90 μm)
Substrate surface treatment: buffing coating: spray coating coating conditions: discharge rate (110 cc / min), conveyor speed (2.3 m / min), disk rotation speed (30000 rpm), applied voltage (−35 KV)
Wet film thickness: 100-110 μm
Pre-drying: 80 ° C., 20 minutes Exposure: 300 mJ / cm ² on the photosensitive resin composition (main wavelength 365 nm, “HMW-680GW” manufactured by Oak Co.)
Alkali development: 1% by weight Na ₂ CO ₃ aqueous solution, liquid temperature 30 ° C., spray pressure 0.2 MPa, development time 60 seconds Post cure: 150 ° C., 60 minutes

The evaluation items are as follows.
(1) Thixo ratio After dilution with a solvent (propylene glycol monomethyl ether) so as to be 60 to 65 seconds (25 ° C.) with an Iwata cup, using a viscometer RVT type manufactured by Brookfield, at a spindle rotation speed of 5 rpm. The BF viscosity (η5) of the photosensitive resin composition at a temperature of 25 ° C. and the BF viscosity (η50) of the photosensitive resin composition at a temperature of 25 ° C. at a spindle rotation speed of 50 rpm were measured. And thixo ratio ((eta) 5 / (eta) 50) was computed from these measured values.

(2) Sagging property With respect to the substrate after the preliminary drying performed in the test piece preparation step, the coating film of the photosensitive resin composition was visually evaluated on the following criteria.
：: No sagging of the coating on the fine wire pattern portion with a conductor thickness of 90 μm ○: Although there is a sagging of the coating on the thin wire pattern portion with a conductor thickness of 90 μm, there is no sagging of the coating on the fine wire pattern portion with a conductor thickness of 60 μm Δ: The thin line pattern portion with a conductor thickness of 60 μm has a sagging of the coating film, but the thin wire pattern portion with a conductor thickness of 35 μm has no sagging of the coating film X: The sagging of the coating film on the thin wire pattern portion with a conductor thickness of 35 μm (conductor thickness 18 μm) There is no sagging of the coating on the fine line pattern part of

(3) Sensitivity In the above test piece preparation process, a step tablet for sensitivity measurement (21 stages of Kodak) is installed on the coating film on the substrate after preliminary drying at 80 ° C. for 20 minutes, and the main wavelength is passed through the step tablet. Is measured using an integrating light meter (“UV-351”, manufactured by Oak Corporation), and irradiated with 300 mJ / cm ² as a test piece, and 1% by mass of Na _2. The portion of the exposed portion that was not removed after developing for 60 seconds at a spray pressure of 0.2 MPa using a CO ₃ aqueous solution was recorded as a number (number of steps) and evaluated according to the following criteria.
○: 8 steps or more ×: 7 steps or less

(4) Spray coating property The appearance of the coating film surface after preliminary drying in the test piece preparation step was visually observed and evaluated according to the following criteria.
◎: No bubbles or yuzu skin, good leveling ○: Some yuzu skin, or slightly thin covering near Cu foil Δ: In addition to some yuzu skin, the surface of the coating film is slightly lost ×: Yuzu skin is present or spray coating is not possible

  The results of the evaluation are shown in Table 2 below.

  As shown in Table 2 above, carboxyl is a reaction product obtained by reacting a glycidyl compound having a radical polymerizable unsaturated group and an epoxy group with a carboxyl group of a polybasic acid-modified radical polymerizable unsaturated monocarboxylic oxide epoxy resin. The synthetic resin (A-1) corresponding to the group-containing photosensitive resin (carboxyl group-containing photosensitive resin of component (A)) is added to the quaternary ammonium salt represented by the above general formula (I). Bentonite treated with quaternary ammonium salt of component (E), which is bentonite treated with stearyldimethylammonium, and about 5.0 mass with respect to 100 mass parts of carboxyl group-containing photosensitive resin of component (A) Parts to about 18 parts by mass of (F) hydrophobic silica, Examples 1 to 7 were spray coated on a conductor pattern having a thickness of 35 μm or more. Therefore, even if the photosensitive resin composition is thickly applied with a wet film thickness of 100 to 110 μm, it has excellent sensitivity, can prevent dripping, and can form a cured coating film with excellent appearance in spray coating. It was.

  Moreover, (F) hydrophobic silica is about 6.0 mass part-about 13 mass parts with respect to 100 mass parts of carboxyl group-containing photosensitive resin of (A) component, (E) Quaternary ammonium salt of a component. In Examples 2 to 4, in which the processed bentonite was blended in an amount of about 9.0 parts by weight to about 18 parts by weight, the photosensitive resin composition was thickly applied with a wet film thickness of 100 to 110 μm by a spray coating method. However, without sacrificing excellent sensitivity, sagging can be prevented even for a conductor pattern having a thickness of 60 μm, and the appearance of the cured coating film can be further improved.

  On the other hand, as shown in Table 2, in Comparative Example 1 in which about 4.0 parts by mass of (F) hydrophobic silica was blended with 100 parts by mass of the carboxyl group-containing photosensitive resin of component (A), Although the sensitivity was good even with a film thickness of 100 to 110 μm, sagging occurred on a conductor pattern with a thickness of 35 μm. In Comparative Example 4 in which about 27 parts by mass of (F) hydrophobic silica was blended with 100 parts by mass of the carboxyl group-containing photosensitive resin of component (A), the sensitivity was good even with a wet film thickness of 100 to 110 μm. However, a good appearance was not obtained by spray coating. In addition, a comparison of a carboxyl group-containing photosensitive resin in which a glycidyl compound having a radical polymerizable unsaturated group and an epoxy group was not reacted with the carboxyl group of a polybasic acid-modified radical polymerizable unsaturated monocarboxylic oxide epoxy resin In Examples 2 and 7, good sensitivity was not obtained.

  Further, in Comparative Example 3 in which hydrophilic silica was blended in place of (F) hydrophobic silica, sagging occurred on a conductor pattern having a thickness of 35 μm. In addition, instead of the bentonite treated with the quaternary ammonium salt of the component (E) in Comparative Example 5 in which the bentonite treated with the quaternary ammonium salt of the component (E) was not blended, stearylbenzyldimethyl chloride In Comparative Example 6 in which ammonium-treated bentonite was blended, sagging occurred with respect to a conductor pattern having a thickness of 35 μm, and a good appearance was not obtained in spray coating.

  In the present invention, even a photosensitive resin composition thickly applied using a spray coating method has excellent sensitivity, can prevent sagging, and can form a cured coating film having an excellent appearance. The utility value is high in a field in which an insulating protective film such as a solder resist film is provided on a printed wiring board having a thick conductor pattern (for example, a thickness of 35 μm or more).

Claims (8)

(A) A hydroxyl group of a radically polymerizable unsaturated monocarboxylic oxide epoxy resin, which is a reaction product of a polyfunctional epoxy resin having two or more epoxy groups in one molecule and a radically polymerizable unsaturated monocarboxylic acid, Reaction product of a glycidyl compound having a radical polymerizable unsaturated group and an epoxy group reacted with a carboxyl group of a polybasic acid-modified radical polymerizable unsaturated monocarboxylic oxide epoxy resin, which is a compound reacted with a basic acid or its anhydride A carboxyl group-containing photosensitive resin that is a product,
(B) a photopolymerization initiator;
(C) a reactive diluent;
(D) an epoxy compound;
(E) The following general formula (I)
[Chemical 1]
[R ¹ R ² R ³ R ⁴ —N] ⁺ X ⁻ (I)
(Wherein R ¹ , R ² , R ³ and R ⁴ are each independently a saturated aliphatic hydrocarbon group having 1 to 25 carbon atoms or an unsaturated aliphatic hydrocarbon group having 2 to 25 carbon atoms, X is , Represents a halogen selected from the group consisting of fluorine, chlorine, bromine and iodine.)
Bentonite treated with a quaternary ammonium salt represented by:
(F) hydrophobic silica;
Including
The photosensitive resin composition which said (F) hydrophobic silica contains 4.5-20 mass parts with respect to 100 mass parts of carboxyl group-containing photosensitive resin of said (A) component.   The bentonite treated with the quaternary ammonium salt of the component (E) contains 5.0 parts by mass to 20 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin of the component (A). The photosensitive resin composition as described in 2.   The (F) hydrophobic silica is contained in an amount of 5.5 to 13.5 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin of the component (A), and the quaternary of the component (E). The photosensitive resin composition according to claim 1 or 2, wherein the bentonite treated with an ammonium salt contains 8.0 parts by mass to 18 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin of the component (A). object.   The mass of bentonite treated with the quaternary ammonium salt of component (E): The mass of (F) hydrophobic silica is in the range of 1.0: 0.30 to 3.0. The photosensitive resin composition of any one of these.   The photosensitive resin composition according to claim 1, wherein the (F) hydrophobic silica is silica modified with an alkylsilyl group.   The photosensitive resin composition according to any one of claims 1 to 5, wherein the quaternary ammonium salt is a distearyldimethylammonium salt.   The photocured material of the photosensitive resin composition of any one of Claims 1 thru | or 6.   The wiring board which has a photocuring film of the photosensitive resin composition of any one of Claims 1 thru | or 6.