JP7133594B2 - Photosensitive resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photosensitive resin composition, for example, a photosensitive resin composition useful as an insulating protective film for a circuit board, and a printed wiring board having a film obtained by photocuring the photosensitive resin composition.

Circuit boards such as printed wiring boards are used to form conductor circuit patterns on the board and mount electronic components on the soldering lands of the pattern by soldering. Circuit parts other than the soldering lands are It is covered with a solder resist film as a permanent insulating protective film. As a result, when soldering electronic components to a circuit board such as a printed wiring board, it is possible to prevent solder from adhering to unnecessary parts, and to prevent the circuit conductors from being corroded by oxidation and humidity due to direct exposure to air. to prevent

The insulating protective film that covers the circuit board is required to have coating film hardness and tackiness (dryness to the touch) during exposure in the process of forming the insulating protective film. Silica is sometimes added as a filler to the photosensitive resin composition in order to impart excellent coating film hardness to the insulating protective film and to impart tackiness during exposure. As a photosensitive resin composition containing silica to improve tackiness (dryness to the touch), (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) an epoxy resin, and (D ) (Meth) acrylic monomer, (E) an alkali-developable photosensitive resin composition containing spherical silica as an inorganic filler, and (B) an acylphosphine oxide-based photopolymerization initiator as a photopolymerization initiator and (C) an alkali-developable photosensitive resin composition containing a bisphenol A novolac type epoxy resin as the epoxy resin (Patent Document 1).

On the other hand, in recent years, as the wiring density of printed wiring boards has become finer, high resolution (high dimensional accuracy) and high precision have been required for the photosensitive resin composition applied as an insulating protective film. However, when silica is blended as a filler into the photosensitive resin composition, there are cases where sufficient resolution of the insulating protective film cannot be obtained.

Moreover, when silica is blended into the photosensitive resin composition as a filler, sufficient sensitivity may not be obtained when the photosensitive resin composition undergoes a photocuring reaction. Furthermore, from the viewpoint of excellent efficiency of forming an insulating protective film, the photosensitive resin composition may be applied to the entire surface of the printed wiring board with an electrostatic spray coating machine, and the photosensitive resin composition has spray coating properties. may be requested.

JP 2015-64546 A

In view of the above circumstances, the present invention provides a photosensitive resin composition that can obtain a cured product with high resolution while having excellent coating film hardness, and has excellent spray coatability, tackiness and sensitivity. The purpose is to provide goods.

In the present invention, by controlling the particle size of the silica particles to be blended in the photosensitive resin composition, it is possible to form a cured product having excellent coating film hardness and resolution. To obtain a photosensitive resin composition excellent in tackiness and sensitivity.

The gist of the configuration of the present invention is as follows.
[1] A photosensitive resin composition containing (A) a photosensitive resin, (B) silica, (C) a photopolymerization initiator, (D) a reactive diluent, and (E) an epoxy compound There is
The photosensitive resin composition, wherein the silica (B) has a particle diameter D50 at a cumulative volume percentage of 50% by volume of 0.50 μm or more and 2.00 μm or less.
[2] The photosensitive resin composition according to [1], which contains 2.0 parts by mass or more and 30 parts by mass or less of silica (B) based on 100 parts by mass of the (A) photosensitive resin.
[3] The photosensitive resin composition according to [1], which contains 4.0 parts by mass or more and 20 parts by mass or less of silica (B) relative to 100 parts by mass of the (A) photosensitive resin.
[4] The photosensitive property according to any one of [1] to [3], wherein the (B) silica has a particle diameter D50 at a cumulative volume percentage of 50% by volume of 1.20 μm or more and 1.90 μm or less Resin composition.
[5] The (B) silica has a particle diameter D1.0 at a cumulative volume percentage of 1.0% by volume of 0.20 μm or more and 0.54 μm or less, and a particle diameter D99 at a cumulative volume percentage of 99% by volume. , 5.00 μm or more and 8.40 μm or less, the photosensitive resin composition according to any one of [1] to [4].
[6] The (B) silica has a particle diameter D1.0 at a cumulative volume percentage of 1.0% by volume of 0.40 μm or more and 0.54 μm or less, and a particle diameter D99 at a cumulative volume percentage of 99% by volume. , 7.00 μm or more and 8.40 μm or less, the photosensitive resin composition according to [4].
[7] The (B) silica has a particle diameter D10 at a cumulative volume percentage of 10% by volume of 0.30 μm or more and 0.75 μm or less, and a particle diameter D90 at a cumulative volume percentage of 90% by volume is 3.00 μm. The photosensitive resin composition according to any one of [1] to [6], which has a thickness of 5.00 μm or less.
[8] The (B) silica has a particle diameter D10 at a cumulative volume percentage of 10% by volume of 0.50 μm or more and 0.75 μm or less, and a particle diameter D90 at a cumulative volume percentage of 90% by volume is 4.00 μm. The photosensitive resin composition according to [4] or [6], which is at least 5.00 μm or less.
[9] The photosensitive resin composition according to any one of [1] to [8], further comprising (F) other silica having a particle diameter D50 at a cumulative volume percentage of 50% by volume of less than 0.50 μm. thing.
[10] Any one of [1] to [9] containing 1.0 parts by mass or more and 8.0 parts by mass or less of the (F) other silica with respect to 100 parts by mass of the (A) photosensitive resin The photosensitive resin composition described.
[11] Any one of [1] to [10], wherein the (E) epoxy compound is at least one epoxy resin selected from the group consisting of biphenyl-type epoxy resins and triglycidyl isocyanurate-type epoxy resins. The photosensitive resin composition according to .
[12] The photosensitive resin composition according to any one of [1] to [11], which is for spray coating.
[13] A printed wiring board coated with the photosensitive resin composition according to any one of [1] to [12].

According to the aspect of the present invention, by containing silica having a cumulative volume percentage of 50% by volume and a particle diameter D50 of 0.50 μm or more and 2.00 μm or less, it has excellent coating film hardness and high resolution. It is possible to obtain a photosensitive resin composition having excellent spray coatability, tackiness and sensitivity.

According to the aspect of the present invention, by including 2.0 parts by mass or more and 30 parts by mass or less of silica (B) with respect to 100 parts by mass of (A) photosensitive resin, the coating film hardness and tackiness are reliably improved. It is possible to obtain high resolution and sensitivity at the same time.

According to the aspect of the present invention, by including 4.0 parts by mass or more and 20 parts by mass or less of silica (B) with respect to 100 parts by mass of (A) the photosensitive resin, the coating can be performed without impairing the spray coatability. It is possible to improve film hardness and tackiness, and resolution and sensitivity in a well-balanced manner.

According to the aspect of the present invention, (B) the particle diameter D50 at a cumulative volume percentage of silica of 50% by volume is 1.20 μm or more and 1.90 μm or less, so that the coating film hardness, tackiness, resolution, sensitivity And the spray coatability can be further improved.

According to the aspect of the present invention, (B) the particle diameter D1.0 at a cumulative volume percentage of silica of 1.0% by volume is 0.40 μm or more and 0.54 μm or less, and the particle diameter at a cumulative volume percentage of 99% by volume When D99 is 7.00 μm or more and 8.40 μm or less, the coating film hardness, tackiness, resolution, sensitivity and spray coatability can be further improved.

According to the aspect of the present invention, (B) the particle diameter D10 at a cumulative volume percentage of 10% by volume of silica is 0.50 μm or more and 0.75 μm or less, and the particle diameter D90 at a cumulative volume percentage of 90% by volume is 4.0 μm. When the thickness is 00 μm or more and 5.00 μm or less, the coating film hardness, tackiness, resolution, sensitivity and spray coatability can be further improved.

According to the aspect of the present invention, the coating film hardness, tackiness, resolution, sensitivity And it can contribute to the improvement of spray coatability.

According to the aspect of the present invention, by including 1.0 parts by mass or more and 8.0 parts by mass or less of (F) other silica with respect to (A) 100 parts by mass of the photosensitive resin, the coating film hardness, tackiness, It can surely contribute to further improvement of resolution, sensitivity and spray coatability.

Next, the photosensitive resin composition of the present invention will be explained below. The photosensitive resin composition of the present invention comprises (A) a photosensitive resin, (B) silica, (C) a photopolymerization initiator, (D) a reactive diluent, and (E) an epoxy compound. In the photosensitive resin composition containing silica (B), the particle diameter D50 at a cumulative volume percentage of 50% by volume is 0.50 μm or more and 2.00 μm or less.

(A) Photosensitive resin The structure of the photosensitive resin of component (A) is not particularly limited, and examples thereof include resins having one or more photosensitive unsaturated double bonds. Examples of photosensitive resins include carboxyl group-containing photosensitive resins having one or more photosensitive unsaturated double bonds and free carboxyl groups. As the carboxyl group-containing photosensitive resin, for example, acrylic acid or methacrylic acid (hereinafter referred to as "(meth)acrylic acid ), etc. are reacted to obtain a radically polymerizable unsaturated monocarboxylic acid epoxy resin such as epoxy (meth)acrylate, and the resulting radically polymerizable unsaturated Polybasic acid-modified radically polymerizable unsaturated monocarboxylated epoxy such as polybasic acid-modified epoxy (meth)acrylate obtained by reacting hydroxyl group of monocarboxylic epoxy resin with polybasic acid and/or its anhydride resin etc. can be mentioned.

The chemical structure of the polyfunctional epoxy resin is not particularly limited as long as it is a bifunctional or higher epoxy resin. Moreover, the epoxy equivalent of the polyfunctional epoxy resin is not particularly limited, and for example, the upper limit thereof is preferably 3000 g/eq, more preferably 2000 g/eq, and particularly preferably 1500 g/eq. On the other hand, the lower limit is preferably 100 g/eq, particularly preferably 200 g/eq.

Examples of polyfunctional epoxy resins include rubber-modified epoxy resins such as biphenylaralkyl-type epoxy resins, phenylaralkyl-type epoxy resins, biphenyl-type epoxy resins, naphthalene-type epoxy resins, dicyclopentadiene-type epoxy resins, and silicone-modified epoxy resins; -caprolactone-modified epoxy resin, phenol novolak type epoxy resin such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, cresol novolak type epoxy resin such as ortho-cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, cycloaliphatic Examples include polyfunctional epoxy resins, glycidyl ester type polyfunctional epoxy resins, glycidylamine type polyfunctional epoxy resins, heterocyclic polyfunctional epoxy resins, bisphenol-modified novolak type epoxy resins, polyfunctional modified novolac type epoxy resins, and the like. In addition to these epoxy resins, epoxy resins into which halogen atoms such as Br and Cl are further introduced may be used. These polyfunctional epoxy resins may be used alone or in combination of two or more.

The chemical structure of the radically polymerizable unsaturated monocarboxylic acid is not particularly limited, and examples thereof include (meth)acrylic acid, crotonic acid, tiglic acid, angelic acid, and cinnamic acid. Of these, (meth)acrylic acid is preferred because it is readily available and easy to handle. These radically polymerizable unsaturated monocarboxylic acids may be used alone or in combination of two or more.

The method for reacting the polyfunctional epoxy resin and the radically polymerizable unsaturated monocarboxylic acid is not particularly limited. A method of dissolving in a diluent and heating may be mentioned.

A polybasic acid and/or a polybasic acid anhydride undergoes an addition reaction with a hydroxyl group generated by a reaction between a polyfunctional epoxy resin and a radically polymerizable unsaturated monocarboxylic acid to give a radically polymerizable unsaturated monocarboxylic acid epoxy resin. A free carboxyl group is introduced into The chemical structures of polybasic acids and polybasic anhydrides are not particularly limited, and may be either saturated or unsaturated. 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- Tetrahydrophthalic acids such as ethyltetrahydrophthalic acid, hexahydrophthalic acid such as hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid, 3-ethylhexahydrophthalic acid, and 4-ethylhexahydrophthalic acid Phthalic acids, tetrahydrophthalic acids such as methyltetrahydrophthalic acid, endomethylenetetrahydrophthalic acid, and methylendomethylenetetrahydrophthalic acid, trimellitic acid, pyromellitic acid and diglycolic acid. Examples of polybasic acid anhydrides include anhydrides of various polybasic acids described above. These compounds may be used alone or in combination of two or more.

The method for reacting the radically polymerizable unsaturated monocarboxylic acid epoxy resin with the polybasic acid and/or polybasic acid anhydride is not particularly limited. And/or a method of dissolving a polybasic acid anhydride in a non-reactive diluent such as an organic solvent and heating.

The above polybasic acid-modified unsaturated monocarboxylic acid epoxy resin can also be used as a photosensitive resin (carboxyl group-containing photosensitive resin). A polybasic acid-modified radically polymerizable unsaturated group further added with a radically polymerizable unsaturated group obtained by addition reaction of a compound having one or more radically polymerizable unsaturated groups and an epoxy group to a part of the carboxyl group. A saturated monocarboxylated epoxy resin may be used as the photosensitive resin. A polybasic acid-modified radically polymerizable unsaturated monocarboxylic acid epoxy resin to which a radically polymerizable unsaturated group is further added is obtained by further introducing a radically polymerizable unsaturated group into the side chain of the polybasic acid-modified unsaturated monocarboxylic acid epoxy resin. It has the chemical structure Therefore, it is a photosensitive resin (carboxyl group-containing photosensitive resin) whose photosensitivity is further improved than that of polybasic acid-modified unsaturated monocarboxylated epoxy resin.

Examples of compounds having one or more radically polymerizable unsaturated groups and epoxy groups include glycidyl compounds. Examples of glycidyl compounds include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, pentaerythritol triacrylate monoglycidyl ether, and pentaerythritol trimethacrylate monoglycidyl ether. A molecule may have one glycidyl group or may have a plurality of glycidyl groups. Moreover, the compounds having one or more radically polymerizable unsaturated groups and an epoxy group may be used alone, or two or more of them may be used in combination.

The method of reacting the polybasic acid-modified unsaturated monocarboxylic acid epoxy resin and the compound having one or more radically polymerizable unsaturated groups and epoxy groups is not particularly limited. A saturated monocarboxylated epoxy resin, one or more radically polymerizable unsaturated groups, and a compound having an epoxy group are dissolved in a non-reactive diluent such as an organic solvent, followed by heating.

Moreover, as the photosensitive resin, a photosensitive resin having no free carboxyl group may be used. Examples of photosensitive resins having no free carboxyl groups include (meth)acrylate monomer polymers, epoxy (meth)acrylates obtained by reacting (meth)acrylic acid with epoxy resins, urethane (meth)acrylates, and urethane (meth)acrylates. ) acrylates and the like.

Epoxy (meth) acrylates include epoxy (meth) acrylates obtained in the process of preparing the carboxyl group-containing photosensitive resin described above. Urethane (meth)acrylates include, for example, urethane (meth)acrylates obtained by reacting urethane resins with (meth)acrylic acid. A urethane resin is a resin obtained by reacting a compound having two or more isocyanate groups in one molecule with a polyol compound having two or more hydroxyl groups in one molecule. Further, urethane (meth)acrylate is obtained by, for example, reacting (meth)acrylic acid with at least part of the epoxy groups of an epoxy resin having one or more epoxy groups in one molecule to obtain epoxy (meth)acrylate. and urethane (meth)acrylates obtained by addition reaction of a compound having one or more isocyanate groups in one molecule to the generated hydroxyl group.

When the photosensitive resin contains a carboxyl group, the acid value of the photosensitive resin is not particularly limited. Especially preferred. On the other hand, the upper limit of the acid value of the carboxyl group-containing photosensitive resin is preferably, for example, 200 mgKOH/g from the viewpoint of preventing dissolution of the exposed area by an alkaline developer, and does not reduce the moisture resistance and insulation reliability of the photocured product. 150 mgKOH/g is particularly preferable from the viewpoint of reliable prevention.

The weight average molecular weight of the photosensitive resin is not particularly limited, and for example, the lower limit thereof is preferably 6,000, more preferably 7,000, and particularly preferably 8,000 from the viewpoint of toughness of the photocured product. On the other hand, the upper limit of the weight average molecular weight of the photosensitive resin is preferably 200,000, more preferably 100,000, and particularly preferably 50,000 from the viewpoint of compatibility with the non-reactive diluent described later. In addition, the "mass average molecular weight" means the mass average molecular weight measured at room temperature using gel permeation chromatography (GPC) and calculated in terms of polystyrene.

The photosensitive resin may be prepared in the above-described reaction step using the components described above, or a commercially available photosensitive resin may be used. Examples of commercially available photosensitive resins include "SP-4621" (Showa Denko Co., Ltd.), "KAYARAD ZAR-2000", "KAYARAD ZFR-1122", "KAYARAD FLX-2089", and "KAYARAD
ZCR-1569H” (Nippon Kayaku Co., Ltd.), and “Cychromer P (ACA) Z-250” (Daicel-Ornex Co., Ltd.). Moreover, these photosensitive resins may be used alone or in combination of two or more.

(B) Silica with a cumulative volume percentage of 50% by volume and a particle size D50 of 0.50 μm or more and 2.00 μm or less, and a particle size D50 of 0.50 μm or more and 2.00 μm or more with a cumulative volume percentage of 50% by volume, which is the component (B) By blending the following silica, it is possible to form a cured product with excellent coating film hardness and high resolution, and a photosensitive resin composition with excellent spray coatability, tackiness and sensitivity can get things.

Silica has a particle diameter D50 (hereinafter sometimes simply referred to as “D50”) at a cumulative volume percentage of 50% by volume of 0.50 μm or more and 2.00 μm or less. Although not limited, the lower limit of D50 is preferably 1.00 μm, particularly preferably 1.20 μm, from the viewpoint of further improving coating film hardness, tackiness, resolution, sensitivity and spray coatability. On the other hand, the upper limit of D50 is preferably 1.95 μm, more preferably 1.90 μm, more preferably 1.80 μm, from the viewpoint of further improving coating film hardness, tackiness, resolution, sensitivity and spray coatability. Especially preferred.

Silica has a particle diameter D1.0 with a cumulative volume percentage of silica of 1.0% by volume (hereinafter sometimes simply referred to as “D1.0”), if D50 is 0.50 μm or more and 2.00 μm or less. Particle diameter D99 (hereinafter sometimes simply referred to as “D99”) with a cumulative volume percentage of silica of 99% by volume is not particularly limited, but the lower limit of D1.0 is to ensure coating film hardness and tackiness. 0.20 μm is preferable from the viewpoint of obtaining high resolution and sensitivity while improving, and 0.40 μm is more preferable from the viewpoint of further improving coating film hardness, tackiness, resolution, sensitivity and spray coatability. Preferably, 0.45 μm is particularly preferred. On the other hand, the upper limit of D1.0 is preferably 0.54 μm, particularly preferably 0.53 μm, from the viewpoint of further improving coating film hardness, tackiness, resolution, sensitivity and spray coatability. In addition, the lower limit of D99 is preferably 5.00 μm from the viewpoint of obtaining high resolution and sensitivity while reliably improving the coating film hardness and tackiness, and the coating film hardness, tackiness, resolution, and sensitivity. And from the point of further improving the spray coatability, 7.00 μm is more preferable, and 7.50 μm is particularly preferable. On the other hand, the upper limit of D99 is preferably 8.40 μm, particularly preferably 8.35 μm, from the viewpoint of further improving coating film hardness, tackiness, resolution, sensitivity and spray coatability.

If D50 is 0.50 μm or more and 2.00 μm or less, silica has a particle diameter D10 (hereinafter sometimes simply referred to as “D10”) with a cumulative volume percentage of 10% by volume of silica, and a cumulative volume percentage of silica is The 90% by volume particle diameter D90 (hereinafter sometimes simply referred to as “D90”) is not particularly limited, but the lower limit of D10 ensures that the coating film hardness and tackiness are improved, while maintaining high resolution. 0.30 μm is preferable from the point of obtaining and sensitivity, and 0.50 μm is more preferable from the point of further improving coating film hardness, tackiness, resolution, sensitivity and spray coatability, and 0.60 μm is particularly preferable. . On the other hand, the upper limit of D10 is preferably 0.75 μm, particularly preferably 0.70 μm, from the viewpoint of further improving coating film hardness, tackiness, resolution, sensitivity and spray coatability. In addition, the lower limit of D90 is preferably 3.00 μm from the viewpoint of obtaining high resolution and sensitivity while reliably improving the coating film hardness and tackiness, and the coating film hardness, tackiness, resolution, and sensitivity. And from the point of further improving the spray coatability, 4.00 μm is more preferable, and 4.30 μm is particularly preferable. On the other hand, the upper limit of D90 is preferably 5.00 μm, particularly preferably 4.90 μm, from the viewpoint of further improving coating film hardness, tackiness, resolution, sensitivity and spray coatability.

The above D1.0, D10, D50, D90, and D99 are based on the volume-based cumulative distribution when the particle size distribution of silica is measured with a laser particle size measuring device in accordance with JIS Z 8825-1. Particle diameter of 1.0% by volume from the small diameter side of the particle size distribution, Particle diameter of 10% by volume from the small diameter side of the particle size distribution, Particle diameter of 50% by volume from the small diameter side of the particle size distribution, 90% by volume from the small diameter side of the particle size distribution means a particle diameter of 99% by volume from the small diameter side of the particle size distribution.

The particle shape of silica is not particularly limited, but may be spherical. The silica may be silica that has not been surface-treated (untreated silica), or surface-treated silica having a surface coated with an organic compound or the like.

The content of silica having a D50 of 0.50 μm or more and 2.00 μm or less is not particularly limited. 2.0 parts by mass is preferable from the viewpoint of obtaining high resolution and sensitivity while reliably improving the coating film hardness and tackiness. 4.0 parts by mass is more preferable from the viewpoint of improving image quality and sensitivity in a well-balanced manner, and 8.0 parts by mass is particularly preferable from the viewpoint of further improving spray coating properties. On the other hand, the upper limit of the content of silica having a D50 of 0.50 μm or more and 2.00 μm or less ensures that the resolution and sensitivity are improved with respect to 100 parts by mass of the photosensitive resin, while achieving a high coating film hardness. 30 parts by mass is preferable from the point of obtaining tackiness, and 20 parts by mass is more preferable from the point that the coating film hardness and tackiness, resolution and sensitivity can be improved in a well-balanced manner without impairing the spray coatability. , 15 parts by mass is particularly preferred from the viewpoint of further improving the sensitivity and spray coatability.

(C) Photopolymerization Initiator The photopolymerization initiator that is the component (C) is not particularly limited, and any of them can be used. Examples of photopolymerization initiators include 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methyl benzoyl)-9H-carbazol-3-yl]-,1-(O-acetyloxime), 2-(acetyloxyiminomethyl)thioxanthene-9-one, 1,8-octanedione, 1,8-bis[ 9-ethyl-6-nitro-9H-carbazol-3-yl]-, 1,8-bis(O-acetyloxime), 1,8-octanedione, 1,8-bis[9-(2-ethylhexyl) -6-nitro-9H-carbazol-3-yl]-, 1,8-bis(O-acetyloxime), (Z)-(9-ethyl-6-nitro-9H-carbazol-3-yl) (4 Oxime ester photopolymerization initiators such as -((1-methoxypropan-2-yl)oxy)-2-methylphenyl)methanone and O-acetyloxime are included. In addition, photopolymerization initiators other than oxime ester photopolymerization initiators may be used. isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1-benzyl-1-(dimethylamino ) propyl-4-morpholinophenyl-ketone, 2-methyl-4′-(methylthio)-2-morpholinopropiophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone- 1,2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p -phenylbenzophenone, 4,4'-bis(diethylamino)benzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone , 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ethyl ester, and the like. These compounds may be used alone or in combination of two or more.

The content of the photopolymerization initiator is not particularly limited, but is preferably 5 parts by mass or more and 40 parts by mass or less, particularly preferably 10 parts by mass or more and 30 parts by mass or less, relative to 100 parts by mass of the photosensitive resin.

(D) Reactive diluent The reactive diluent as component (D) is, for example, a photopolymerizable monomer, and is a compound having at least one, preferably two or more polymerizable double bonds per molecule. be. The reactive diluent enhances the photocuring of the photosensitive resin composition and contributes to improving the hardness, acid resistance, heat resistance and alkali resistance of the photocured product.

Examples of reactive diluents include monofunctional (meth)acrylate monomers and bifunctional or higher (meth)acrylate monomers. Monofunctional (meth)acrylate monomers such as 2-hydroxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, diethylene glycol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acryl rate, caprolactone-modified (meth)acrylate. In addition, bifunctional or higher (meth)acrylate monomers include, for example, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, (Meth)acrylates, neopentyl glycol adipate di(meth)acrylate, neopentyl glycol hydroxypivalate di(meth)acrylate, dicyclopentanyl di(meth)acrylate, ethylene oxide-modified phosphate di(meth)acrylate, cyclohexyl allylate 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, dipentaerythritol hexa(meth)acrylate and the like. These compounds may be used alone or in combination of two or more.

The content of the reactive diluent is not particularly limited, but is preferably 10 parts by mass or more and 100 parts by mass or less, particularly preferably 20 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the photosensitive resin.

(E) Epoxy Compound The epoxy compound, which is the component (E), increases the crosslink density of the photocured product of the photosensitive resin composition and contributes to the improvement of the mechanical strength of the photocured product. Examples of epoxy compounds include epoxy resins. Examples of epoxy resins include biphenyl type epoxy resins, biphenylaralkyl type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins such as tetramethylbisphenol F type epoxy resins, phenol novolac type epoxy resins, and cresol novolak type epoxy resins. , dicyclopentadiene type epoxy resin, adamantane type epoxy resin, triglycidyl isocyanurate type epoxy resin, and the like. Of these, bisphenol A type epoxy resin, biphenyl type epoxy resin, and tetramethylbisphenol F type epoxy resin are preferable, and biphenyl type epoxy resin and tetramethylbisphenol F type epoxy resin are particularly preferable, from the viewpoint of further improving pot life. Among these, triglycidyl isocyanurate type epoxy resins are preferable from the viewpoint of further improving coating film hardness. These compounds may be used alone or in combination of two or more.

The content of the epoxy compound is not particularly limited, but is preferably 10 parts by mass or more and 100 parts by mass or less, particularly preferably 20 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the photosensitive resin.

In the photosensitive resin composition of the present invention, in addition to the above components (A) to (E), if necessary, (F) silica having a cumulative volume percentage of 50% by volume and a particle diameter D50 of less than 0.50 μm (hereinafter sometimes simply referred to as “other silica”) may be blended. Other silica contributes to improving coating film hardness, tackiness, resolution, sensitivity and spray coatability.

The D50 of the other silica that is the component (F) is not particularly limited as long as it is less than 0.50 µm, preferably less than 0.30 µm, particularly preferably less than 0.10 µm. Other silicas can include, for example, fumed silica. Fumed silica can be hydrophobic fumed silica or hydrophilic fumed silica.

The content of other silica is not particularly limited, but the lower limit is certain to further improve the coating film hardness, tackiness, resolution, sensitivity and spray coatability with respect to 100 parts by mass of the photosensitive resin. 1.0 parts by mass is preferable, and 2.0 parts by mass is particularly preferable from the viewpoint of contributing to the On the other hand, the upper limit of the content of other silica is 15 from the viewpoint of contributing to further improvement in coating film hardness, tackiness, resolution, sensitivity and spray coatability with respect to 100 parts by mass of the photosensitive resin. Parts by mass are preferred, and 8.0 parts by mass is particularly preferred from the viewpoint of reliably contributing to further improvements in coating film hardness, tackiness, resolution, sensitivity and spray coatability.

In addition to the components (A) to (F) described above, the photosensitive resin composition of the present invention may optionally contain other components such as extender pigments, colorants (color pigments), additives, non- A reactive diluent or the like may be added as appropriate.

Examples of extender pigments include talc, barium sulfate, hydrophobic silica, alumina, aluminum hydroxide, and mica. The coloring agent is not particularly limited and may be a pigment, a dye, or the like, and may be any color such as a white coloring agent, a blue coloring agent, a green coloring agent, a yellow coloring agent, a purple coloring agent, a black coloring agent, an orange coloring agent, or the like. agents can also be used. Examples of the coloring agent include inorganic coloring agents such as titanium oxide (rutile type, anatase type) which is a white coloring agent, carbon black which is a black coloring agent and acetylene black, and phthalocyanine green and blue which are green coloring agents. Organic coloring agents such as phthalocyanine-based coloring agents such as phthalocyanine blue and lionol blue, yellow coloring agents such as anthraquinone-based coloring agents, and diketopyrrolopyrrole-based coloring agents such as orange coloring agents such as chromophthalorange can be exemplified. .

Additives include, for example, mercaptobenzoxazale and its derivatives, dicyandiamide (DICY) and its derivatives, melamine and its derivatives, boron trifluoride-amine complex, organic acid hydrazides, diaminomaleonitrile (DAMN) and its derivatives, Curing accelerators such as guanamine and its derivatives, amine imides (AI) and polyamines, metal salts of acetylacetone such as Zn acetylacenate and Cr acetylacenate, enamines, tin octylate, quaternary sulfonium salts, triphenylphosphine, 2 - Imidazoles such as mercaptobenzimidazole, imidazolium salts, thermosetting accelerators such as triethanolamine borate, and thixotropic agents such as polycarboxylic acid amides.

A non-reactive diluent is for adjusting the coatability and drying properties of the photosensitive resin composition. Non-reactive diluents include, for example, organic solvents. Examples of organic solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; Carbitols, glycol ethers such as propylene glycol monomethyl ether, 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 esters of the above glycol ethers; alcohols such as ethanol, propanol, cyclohexanol, ethylene glycol and propylene glycol. These may be used alone or in combination of two or more.

The method for producing the photosensitive resin composition of the present invention described above is not limited to a specific method. For example, after blending each of the above components in a predetermined ratio, at room temperature (ordinary temperature), a three-roll mill, a ball mill, a sand mill, etc. or kneading or mixing by a stirring means such as a super mixer or a planetary mixer. In addition, prior to kneading or mixing, pre-kneading or pre-mixing may be performed at room temperature (ordinary temperature), if necessary.

Next, an example of how to use the photosensitive resin composition of the present invention will be described. Here, a method for forming an insulating film such as a solder resist film by spray coating the photosensitive resin composition of the present invention on a printed wiring board will be described as an example.

The photosensitive resin composition of the present invention produced as described above is applied to a printed wiring board to a desired thickness, for example, 5 to 100 μm, by spraying to form a coating film. The means of spray coating can be appropriately selected, and examples thereof include an electrostatic spray coating machine, an air spray coating machine, an airless spray coating machine, and the like. After the spray coating of the photosensitive resin composition, pre-drying by heating at a temperature of about 60 to 100° C. for about 15 to 60 minutes is performed as necessary to form a tack-free coating film. Next, a negative film having a translucent pattern other than the lands of the circuit pattern is adhered to the coating film, and ultraviolet rays (for example, wavelengths in the range of 300 to 400 nm) are irradiated from above the negative film to remove the coating film. Light cure. The coating is then developed by removing the non-exposed areas corresponding to the lands with a dilute alkaline aqueous solution. As a developing method, a spray method, a shower method, or the like is used, and examples of the dilute alkaline aqueous solution used include a 0.5 to 5% by mass sodium carbonate aqueous solution. Then, post-curing (main curing treatment) is performed for 20 to 80 minutes in a hot air circulating dryer or the like at 130 to 170° C. to form the desired solder resist film on the printed wiring board.

Examples of the present invention will now be described, but the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

Examples 1-8, Comparative Examples 1-3
Each component shown in Table 1 below was blended in the blending ratio shown in Table 1 below, and mixed and dispersed at room temperature (25 ° C.) using a three-roller to obtain Examples 1 to 8 and Comparative Examples 1 to 3. A photosensitive resin composition for use was prepared. The blending amount of each component shown in Table 1 below indicates parts by mass unless otherwise specified. In addition, the blank part of the compounding amount in the following Table 1 means that there is no compounding.

The details of each component in Table 1 below are as follows.
(A) Photosensitive resin In 250 parts by mass of carbitol acetate, 220 parts by mass of a cresol novolak epoxy resin (ESCN-220, epoxy equivalent: 220, manufactured by Sumitomo Chemical Co., Ltd.) and 72 parts by mass of acrylic acid are dissolved, and the mixture is refluxed. to obtain a cresol novolak type epoxy acrylate. Next, 138.6 parts by mass of hexahydrophthalic anhydride was added to the obtained cresol novolak-type epoxy acrylate, reacted under reflux until the acid value reached the theoretical value, then 56.8 parts by mass of glycidyl methacrylate was added, Further reaction was carried out to obtain a synthetic resin (A-1) of a carboxyl group-containing photosensitive resin having a solid content of 65% by mass.

(B) Silica with a D50 of 0.50 μm or more and 2.00 μm or less SilvorBond 925: SEBELCO (C) Photopolymerization initiator Irgacure 369: Ciba Specialty Chemicals Co., Ltd. NCI-831: ADEKA Corporation
(D) Reactive diluent DPHA: Toagosei Co., Ltd. (E) Epoxy compound YX-4000K: Mitsubishi Chemical Corporation TEPIC-H: Nissan Chemical Industries, Ltd. (F) Silica with D50 less than 0.50 μm Aerosil R974: Nippon Aerosil Co., Ltd., D50 is 12 nm

Extender pigment Barium sulfate B-30: Sakai Chemical Industry Co., Ltd. FH105: Fuji Talc Co., Ltd. Coloring agent Chromophthal yellow AGR: Chiba Specialty Chemicals Co., Ltd. Lionol blue FG-7351: Toyocolor Co., Ltd.

Additive Melanin: Nissan Chemical Co., Ltd. DICY-7: Japan Epoxy Resin Co., Ltd. Antage MB: Kawaguchi Chemical Industry Co., Ltd. BYK-405: BYK Chemie Non-reactive diluent Diethylene glycol monoethyl ether acetate: Sanyo Chemicals Ltd.

Silica MINUSIL 5 with a D50 greater than 2.00 μm: Air Braun

Test body production process board: Printed wiring board (glass epoxy board "FR-4", board thickness 1.6 mm, conductor (Cu foil) thickness 50 μm)
Substrate surface treatment: Buffing Coating: Screen spray coating Coating conditions: Discharge rate (110 cc/min), conveyor speed (2.3 m/min), disk rotation speed (30000 rpm), applied voltage (-35 KV)
DRY film thickness: 35-40 μm, wet film thickness: spray coating 70-80 μm
Pre-drying: 80° C., 20 minutes Exposure: 100 mJ/cm ² on photosensitive resin composition (Oak Manufacturing Co., Ltd. “HMW-680
GW”)
Alkaline development: 1% Na ₂ CO ₃ , solution temperature 30°C, spray pressure 0.2 MPa, development time 60 seconds Post cure (main curing treatment): 150°C, 60 minutes

Evaluation items are as follows.
(1) Resolution (dimensional accuracy)
The line width of the exposed portion of the photosensitive resin composition formed on the Cu foil through a photomask (line 100 μm) was measured with an optical microscope (50×) and evaluated according to the following criteria.
◎: Line width less than 105 μm ○: Line width 105 μm or more and less than 110 μm △: Line width 110 μm or more and less than 115 μm ×: Line width 115 μm or more

(2) Pencil Hardness The pencil hardness of the cured coating film on the Cu foil of the substrate was evaluated according to the test method of JISK-5600-5-4.
◎: 7H or more ○: 5H or more and 6H or less △: 3H or more and 4H or less ×: 2H or less

(3) Tackiness The stickiness to the coating film when the negative film was brought into contact with the coating film after preliminary drying and exposed to light was evaluated according to the following criteria.
◎: No sticking to the coating film ○: Slightly sticking to the coating film, but no sticking marks on the coating film △: Sticking traces remaining on the coating film with adhesion of

(4) Sensitivity After pre-drying at 80°C for 20 minutes, a step tablet for sensitivity measurement (Kodak 21 stage) was placed on the coated substrate, and the amount of UV irradiation with a main peak of 365 nm was measured through the step tablet. - A test piece irradiated with 100 mJ / cm ² using an integrated photometer of Ku Seisakusho Co., Ltd., using a 1% by mass sodium carbonate aqueous solution, a spray pressure of 0.2 MPa,
The portion of the exposed portion that was not removed after development was performed at a development time of 60 seconds was expressed by a number (the number of steps) and evaluated according to the following criteria.
◎: 9 steps or more ○: 7-8 steps △: 5-6 steps ×: 4 steps or less

(5) Spray Coatability The surface appearance of the coating film after predrying was visually observed and evaluated according to the following criteria.
◎: No air bubbles or orange peel, good leveling property ○: There is some orange peel, or the covering near the Cu foil is slightly thin △: In addition to some orange peel, the coating surface is slightly depleted. ×: There is orange skin, or spray coating is not possible

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

As shown in Table 1 above, in Examples 1 to 8 in which silica having a D50 of 0.50 μm or more and 2.00 μm or less, which is the component (B), was blended, excellent coating film hardness and high resolution were obtained. It was possible to form a cured product with and to obtain a photosensitive resin composition excellent in spray coatability, tackiness and sensitivity. In Example 3, about 12 parts by mass of silica having a D50 of 0.50 μm or more and 2.00 μm or less, which is the component (B), was added to 100 parts by mass of the photosensitive resin (solid content (resin content), hereinafter the same). Compared to Example 1 in which about 2.4 parts by mass of silica having a D50 of 0.50 μm or more and 2.00 μm or less, which is the component (B), was blended with respect to 100 parts by mass of the photosensitive resin, the coating film hardness, tackiness, and sprayability were improved. The coatability is further improved, and compared with Example 2 in which about 4.8 parts by mass of silica having a D50 of 0.50 μm or more and 2.00 μm or less, which is the component (B), is blended with 100 parts by mass of the photosensitive resin. Further improved spray coatability.

In Example 3, about 12 parts by mass of silica having a D50 of 0.50 μm or more and 2.00 μm or less, which is the component (B), was mixed with 100 parts by mass of the photosensitive resin. ) Component D50 is 0.50 μm or more and 2.00 μm or less silica is blended about 29 parts by mass, the resolution, sensitivity, and spray coatability are further improved, and the photosensitive resin 100 mass Compared to Example 4, in which about 19 parts by mass of silica having a D50 of 0.50 μm or more and 2.00 μm or less, which is the component (B), was blended with respect to 1 part, sensitivity and spray coatability were further improved.

In addition, Example 2, in which about 2.4 parts by mass of silica having a D50 of less than 0.50 μm, which is the component (F), is blended with respect to 100 parts by mass of the photosensitive resin, has a D50 of the component (F) of less than 0.50 μm. The resolution, coating film hardness, tackiness, sensitivity, and spray coatability were further improved compared to Example 6 in which about 9.6 parts by mass of silica was added to 100 parts by mass of the photosensitive resin. In addition, Example 3 using silica having a D50 of 1.75 μm as the component (B) was compared with Example 7 using silica having a D50 of 1.12 μm as the component (B). Further improved coating film hardness, tackiness, sensitivity and spray coating properties. Furthermore, Example 8 using a triglycidyl isocyanurate type epoxy resin as the epoxy compound (E) further improved the coating film hardness compared to Example 3 using a biphenyl type epoxy resin.

On the other hand, as shown in Table 1 above, in Comparative Examples 1 to 3 in which silica having a D50 of 2.09 μm was used instead of silica having a D50 of 0.50 μm or more and 2.00 μm or less, the resolution and the coating film At least one property of hardness and sensitivity could not be obtained.

The photosensitive resin composition of the present invention can form a cured product with high resolution while having excellent coating film hardness, and is a photosensitive resin excellent in spray coatability, tackiness and sensitivity. Since the composition can be obtained, it is highly useful in the field of insulating coatings for printed wiring boards, such as solder resist films.

Claims (10)

A photosensitive resin composition comprising (A) a photosensitive resin, (B) silica, (C) a photopolymerization initiator, (D) a reactive diluent, and (E) an epoxy compound,
The (B) silica has a particle diameter D50 at a cumulative volume percentage of 50% by volume of 1.20 μm or more and 1.80 μm or less,
2.0 parts by mass or more and 20 parts by mass or less of silica (B) with respect to 100 parts by mass of the (A) photosensitive resin,
(F) other silica having a cumulative volume percentage of 50% by volume and a particle diameter D50 of less than 0.50 μm is added to 1.0 parts by mass or more and 8.0 parts by mass or less with respect to 100 parts by mass of the photosensitive resin (A) including
The photosensitive resin composition, wherein the silica blended in the photosensitive resin composition is the (B) silica and the (F) other silica. The photosensitive resin composition according to claim 1, wherein the (B) silica is contained in an amount of 4.0 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the (A) photosensitive resin. 5. The (B) silica has a particle diameter D1.0 at a cumulative volume percentage of 1.0% by volume of 0.20 μm or more and 0.54 μm or less, and a particle diameter D99 at a cumulative volume percentage of 99% by volume. 3. The photosensitive resin composition according to claim 1, having a thickness of 00 μm or more and 8.40 μm or less. 7. The (B) silica has a particle diameter D1.0 at a cumulative volume percentage of 1.0% by volume of 0.40 μm or more and 0.54 μm or less, and a particle diameter D99 at a cumulative volume percentage of 99% by volume. The photosensitive resin composition according to claim 1 , having a thickness of 00 µm or more and 8.40 µm or less. 5. The (B) silica has a particle diameter D10 at a cumulative volume percentage of 10% by volume of 0.30 μm or more and 0.75 μm or less, and a particle diameter D90 at a cumulative volume percentage of 90% by volume of 3.00 μm or more. 5. The photosensitive resin composition according to any one of claims 1 to 4 , which has a thickness of 00 µm or less. 4. The (B) silica has a particle diameter D10 at a cumulative volume percentage of 10% by volume of 0.50 μm or more and 0.75 μm or less, and a particle diameter D90 at a cumulative volume percentage of 90% by volume is 4.00 μm or more. 5. The photosensitive resin composition according to claim 1 or 4 , which has a particle size of 00 μm or less. The photosensitive material according to any one of claims 1 to 6 , wherein (E) the epoxy compound is at least one epoxy resin selected from the group consisting of biphenyl-type epoxy resins and triglycidyl isocyanurate-type epoxy resins. Resin composition. 7. The photosensitive resin composition according to any one of claims 1 to 6 , wherein (E) the epoxy compound is a triglycidyl isocyanurate type epoxy resin. 9. The photosensitive resin composition according to any one of claims 1 to 8 , which is for spray coating. A printed wiring board coated with the photosensitive resin composition according to any one of claims 1 to 9 .