JP2020042162A - Photosensitive resin composition - Google Patents

Abstract

To provide a photosensitive resin composition that makes it possible to obtain a photocured product having an excellent matte appearance while having excellent insulation reliability, heat resistance, flexibility.SOLUTION: A photosensitive resin composition contains (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) an epoxy compound, (D) an aliphatic urea compound with a melting point of 100°C-200°C, and (E) a reactive diluent.SELECTED DRAWING: None

Description

  The present invention relates to a coating material, in particular, a photosensitive resin composition capable of forming a coating material having a matte appearance, excellent flexibility, heat resistance, and excellent insulating properties, and a coating film obtained by applying the photosensitive resin composition to a film. The present invention relates to a dry film having:

  A conductor circuit pattern of a conductor (for example, copper foil) is formed on a substrate, and an electronic component is mounted on a soldering land of the circuit pattern by soldering. A circuit portion excluding the soldering land serves as a protective film. It is covered with an insulating film (for example, a solder resist film). As the protective film, a photocured film of a photosensitive resin composition containing a photosensitive resin and a photopolymerization initiator may be used.

  Further, a photo-cured film of a photosensitive resin composition may be used as a protective film for a flexible printed wiring board. In this case, the photocurable film is required to have flexibility (flexibility) in addition to various properties such as insulation reliability and heat resistance.

  On the other hand, the photocured film of the photosensitive resin composition may be required to have a matte appearance depending on the use conditions as a protective film and the like. Therefore, a solder resist ink composition containing a carboxyl group-containing photosensitive resin, a photopolymerization initiator, an organic filler, a diluent, and an epoxy resin has been proposed (Patent Document 1). In Patent Document 1, a matting effect is obtained by blending an organic filler such as polymethacrylate particles and silicone resin.

  However, as described in Patent Document 1, in a photosensitive resin composition exhibiting a matting effect by blending an organic filler, since the reactivity between the organic filler and the carboxyl group-containing photosensitive resin is low, insulation reliability is low. There is a problem that there is room for improvement in the heat resistance, and when an organic filler is blended, sufficient heat resistance may not be obtained.

  Further, by blending an inorganic filler such as silica particles in place of the organic filler, a matting effect is exerted on the photosensitive resin composition. However, when an inorganic filler such as silica particles is blended, there is a problem that excellent flexibility (flexibility) may not be imparted to the photocurable film.

JP 2006-40935 A

  In view of the above circumstances, an object of the present invention is to provide a photosensitive resin composition capable of obtaining a photocured product having excellent matte appearance, excellent insulation reliability, heat resistance, and flexibility. And

（式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｒ^６、Ｒ^７は、それぞれ、独立して、炭素数１〜２０個の飽和脂肪族炭化水素基、または少なくとも１つのエチレン性不飽和基を有する炭素数２〜２０個の不飽和脂肪族炭化水素基を意味する。）で表される化合物であることを特徴とする［１］に記載の感光性樹脂組成物。
［３］前記Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｒ^６、Ｒ^７は、それぞれ、独立して、炭素数１〜５個の飽和脂肪族炭化水素基であることを特徴とする［２］に記載の感光性樹脂組成物。
［４］前記Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｒ^６、Ｒ^７は、メチル基であることを特徴とする［２］または［３］に記載の感光性樹脂組成物。
［５］前記（Ａ）カルボキシル基含有感光性樹脂１００質量部に対し、前記（Ｄ）融点が１００℃〜２００℃である脂肪族系ウレア化合物が、１．０質量部以上３０質量部以下含有することを特徴とする［１］乃至［４］のいずれか１つに記載の感光性樹脂組成物。
［６］塗工した前記感光性樹脂組成物を、７０℃にて２０分間乾燥後、４００ｍＪ／ｃｍ^２の紫外線を照射して、１５０℃、６０分間にて熱硬化させた後の光硬化物表面を、光沢計を用いて６０度鏡面反射率を測定することにより得られるグロス値が４０％以下であることを特徴とする［１］乃至［５］のいずれか１つに記載の感光性樹脂組成物。
［７］前記（Ｂ）光重合開始剤が、オキシムエステル化合物及び／またはα−アミノアルキルフェノン化合物を含むことを特徴とする［１］乃至［６］のいずれか１つに記載の感光性樹脂組成物。
［８］［１］乃至［７］のいずれか１つに記載の感光性樹脂組成物の光硬化物。
［９］［１］乃至［７］のいずれか１つに記載の感光性樹脂組成物を有するドライフィルム。 The gist of the configuration of the present invention is as follows.
[1] (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) an epoxy compound, (D) an aliphatic urea compound having a melting point of 100 ° C to 200 ° C, E) a reactive diluent; and a photosensitive resin composition.
[2] The aliphatic urea compound (D) having a melting point of 100 ° C. to 200 ° C. is represented by the following general formula (1):

(Wherein, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ each independently represent a saturated aliphatic hydrocarbon group having 1 to 20 carbon atoms, or at least one of (2) means a compound having 2 to 20 carbon atoms and an unsaturated aliphatic hydrocarbon group having an ethylenically unsaturated group).
[3] The above R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ are each independently a saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms. The photosensitive resin composition according to [2], wherein
[4] The photosensitive resin composition according to [2] or [3], wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ are methyl groups. .
[5] The aliphatic urea compound (D) having a melting point of 100 ° C. to 200 ° C. is contained in an amount of 1.0 to 30 parts by mass with respect to 100 parts by mass of the (A) carboxyl group-containing photosensitive resin. The photosensitive resin composition according to any one of [1] to [4].
[6] A photo-cured product obtained by drying the coated photosensitive resin composition at 70 ° C. for 20 minutes, irradiating with ultraviolet rays of 400 mJ / cm ² , and heat-curing at 150 ° C. for 60 minutes. The photosensitivity according to any one of [1] to [5], wherein a gloss value obtained by measuring a 60-degree specular reflectance of the surface using a gloss meter is 40% or less. Resin composition.
[7] The photosensitive resin according to any one of [1] to [6], wherein the photopolymerization initiator (B) contains an oxime ester compound and / or an α-aminoalkylphenone compound. Composition.
[8] A photocured product of the photosensitive resin composition according to any one of [1] to [7].
[9] A dry film comprising the photosensitive resin composition according to any one of [1] to [7].

  In the present specification, the “melting point” means a temperature at a transition point at which a decrease in calorific value, which indicates endotherm, is measured by a differential scanning calorimetry (DSC) at a heating rate of 10 ° C./min.

  According to an embodiment of the present invention, a photosensitive resin composition containing a carboxyl group-containing photosensitive resin, a photopolymerization initiator, and an epoxy compound has an aliphatic urea compound having a melting point of 100 ° C to 200 ° C. By being blended, a photocured product having excellent insulation reliability, heat resistance and flexibility and having an excellent matte appearance can be obtained.

  According to the aspect of the present invention, since the aliphatic urea compound having a melting point of 100 ° C to 200 ° C is a compound represented by the general formula (1), an excellent matte appearance can be reliably obtained. Can be.

According to an embodiment of the present invention, the aliphatic urea compound having a melting point of 100 ° C to 200 ° C with respect to 100 parts by mass of a carboxyl group-containing photosensitive resin contains 1.0 part by mass or more and 30 parts by mass or less. The matte appearance and heat resistance can be reliably improved.

  Next, the photosensitive resin composition of the present invention will be described below. The photosensitive resin composition of the present invention comprises (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) an epoxy compound, and (D) a fat having a melting point of 100 ° C to 200 ° C. A group-containing urea compound and (E) a reactive diluent.

(A) Carboxyl group-containing photosensitive resin The carboxyl group-containing photosensitive resin is not particularly limited. For example, a carboxyl group having one or more, preferably two or more photosensitive unsaturated double bonds in one molecule. Containing resin. As the carboxyl group-containing photosensitive resin, for example, acrylic acid or methacrylic acid (hereinafter, referred to as “(meth) acrylic acid”) is added to at least a part of the epoxy groups of a polyfunctional epoxy resin having two or more epoxy groups in one molecule. ) To obtain a radically polymerizable unsaturated monocarboxylic oxide epoxy resin such as epoxy (meth) acrylate, and the resulting hydroxyl group of the resin is obtained. And a polybasic acid-modified radically polymerizable unsaturated monocarboxylic oxide epoxy resin such as a polybasic acid-modified epoxy (meth) acrylate obtained by reacting a polybasic acid and / or an anhydride thereof.

  The polyfunctional epoxy resin is not particularly limited as long as it is a bifunctional or higher epoxy resin, and an epoxy resin having any chemical structure can be used. The epoxy equivalent of the polyfunctional epoxy resin is not particularly limited, but the upper limit is preferably 3000 g / eq, more preferably 2000 g / eq, and particularly preferably 1500 g / eq. On the other hand, the lower limit of the epoxy equivalent of the polyfunctional epoxy resin is preferably 100 g / eq, and particularly preferably 200 g / eq.

  The polyfunctional epoxy resin, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl aralkyl type epoxy resin, phenyl aralkyl type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, ε-caprolactone-modified epoxy resin, phenol novolak-type epoxy resin, cresol novolak-type epoxy resin, bisphenol-modified novolak-type epoxy resin, cycloaliphatic epoxy resin, glycidyl ester-type epoxy resin, glycidylamine-type epoxy resin, heterocyclic epoxy resin, etc. Can be mentioned. Further, resins obtained by introducing halogen atoms such as Br and Cl into these resins may be used. 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 (meth) acrylic acid, crotonic acid, and cinnamic acid. Among them, (meth) acrylic acid is preferable from the viewpoint of availability. Acids are preferred. These radically polymerizable unsaturated monocarboxylic acids may be used alone or in combination of two or more. The radically polymerizable unsaturated monocarboxylic acid reacts with the epoxy group of the polyfunctional epoxy resin, whereby a photosensitive unsaturated double bond is introduced into the resin to form a photosensitive resin.

  The method of reacting the polyfunctional epoxy resin with the radically polymerizable unsaturated monocarboxylic acid is not particularly limited. For example, the polyfunctional epoxy resin and the radically polymerizable unsaturated monocarboxylic acid may be mixed with a suitable diluent (for example, an organic solvent). ).

The polybasic acid and / or polybasic acid anhydride reacts with the hydroxyl group generated by the reaction between the polyfunctional epoxy resin and the radically polymerizable unsaturated monocarboxylic acid, thereby introducing a photosensitive unsaturated double bond. Free carboxyl groups are further introduced into the resin thus obtained. By introducing a free carboxyl group into a resin into which a photosensitive unsaturated double bond has been introduced, alkali developability is imparted to the resin. The polybasic acid and its anhydride are not particularly limited, and both saturated and unsaturated acids can be used. Polybasic acids include, for example, succinic acid, maleic acid, adipic acid, citric acid, phthalic acid, phthalic acid derivatives (eg, tetrahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, 3-ethyl Tetrahydrophthalic acid, 4-ethyltetrahydrophthalic acid, hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid, 3-ethylhexahydrophthalic acid, 4-ethylhexahydrophthalic acid, methyltetrahydro Phthalic acid, methylhexahydrophthalic acid, endmethylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid), trimellitic acid, pyromellitic acid, diglycolic acid and the like. Examples of polybasic acid anhydrides include anhydrides of these polybasic acids. These compounds may be used alone or in combination of two or more. The method of reacting the radically polymerizable unsaturated monocarboxylic oxide epoxy resin with the polybasic acid and / or polybasic acid anhydride is not particularly limited. For example, the radical polymerizable unsaturated monocarboxylic oxide epoxy resin and the polybasic acid and And / or heating with a polybasic acid anhydride in a suitable diluent (for example, an organic solvent).

  The above-mentioned polybasic acid-modified radically polymerizable unsaturated monocarboxylic oxide epoxy resin can also be used as the carboxyl group-containing photosensitive resin. By reacting a glycidyl compound having one or more radically polymerizable unsaturated groups and an epoxy group with a part of the groups, and further introducing a radically polymerizable unsaturated group into a side chain of the resin, the photosensitive A carboxyl group-containing photosensitive resin having improved properties may be used.

  In the carboxyl group-containing photosensitive resin having improved photosensitivity, a radical polymerizable unsaturated group is added to a side chain of a polybasic acid-modified radical polymerizable unsaturated monocarboxylic oxide epoxy resin skeleton by an addition reaction of a glycidyl compound. Due to the bonding, photopolymerization reactivity, that is, photocurability, is further improved, and more excellent photosensitive characteristics are obtained. Examples of the glycidyl compound include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, pentaerythritol triacrylate monoglycidyl ether, and pentaerythritol trimethacrylate monoglycidyl ether. The compounds having one or more radically polymerizable unsaturated groups and epoxy groups described above may be used alone or in combination of two or more.

  The acid value of the carboxyl group-containing photosensitive resin is not particularly limited, but the lower limit is preferably 30 mgKOH / g, particularly preferably 40 mgKOH / g, from the viewpoint of obtaining reliable alkali developability. On the other hand, the upper limit of the acid value of the carboxyl group-containing photosensitive resin is preferably 200 mgKOH / g from the viewpoint of preventing dissolution of the exposed portion (photocured portion) by the alkali developing solution. From the viewpoint of preventing the property from lowering, 150 mgKOH / g is particularly preferable.

  The weight average molecular weight (Mw) of the carboxyl group-containing photosensitive resin is not particularly limited, but the lower limit is preferably 6000, particularly preferably 7000, from the viewpoint of the toughness and dryness of the cured product. On the other hand, the upper limit of the mass average molecular weight (Mw) of the carboxyl group-containing photosensitive resin is preferably 200,000, more preferably 100,000, and particularly preferably 50,000, from the viewpoint of reliably preventing a decrease in alkali developability.

The carboxyl group-containing photosensitive resin may be synthesized by the above reaction using each of the above starting materials, and a commercially available carboxyl group-containing photosensitive resin may be used. Examples of commercially available carboxyl group-containing photosensitive resins include “SP-4621” (Showa Denko KK), “KAYARAD ZAR-2000”, “ZFR-1122”, and “FLX-208”.
9 "," ZCR-1569H "(Nippon Kayaku Co., Ltd.)," Cyclomer P (ACA) Z-250 "(Daicel Ornex Co., Ltd.) and the like. Further, these carboxyl group-containing photosensitive resins may be used alone or in combination of two or more.

(B) Photopolymerization initiator The photopolymerization initiator is not particularly limited, and any of them can be used. Examples of the photopolymerization initiator include 1,2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyloxime)], and ethanone 1- [9-ethyl-6- (2-methylbenzoyl). ) -9H-Carbazol-3-yl] -1- (0-acetyloxime), 2- (acetyloxyiminomethyl) thioxanthen-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- ( (1-methoxypropane- -Yl) oxy) -2-methylphenyl) methanone An oxime ester-based photopolymerization initiator such as O-acetyloxime, 2-benzyl-2-dimethylamino-1-morpholinophenone) -butanone-1,2- (dimethylamino ) -2-[(4-Methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino- And α-aminoalkylphenone-based photopolymerization initiators such as propanone-1.

Further, as other photopolymerization initiators, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin-based photopolymerization initiators such as benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, Acetophenone-based photopolymerization initiators such as 2,2-dimethoxy-2-phenylacetophenone and 2,2-diethoxy-2-phenylacetophenone; benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, etc. Benzophenone photopolymerization initiators, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, anthraquinones such as 2-aminoanthraquinone Thioxanthone-based photopolymerization initiators such as 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, and 2,4-diethylthioxanthone; ethyl-4- (dimethyl Amino) benzoate, 2-n-butoxyethyl-4- (dimethylamino) benzoate, methyl-4- (dimethylamino) benzoate, isoamyl-4- (dimethylamino) benzoate, 2- (dimethylamino) ethylbenzoate, 2- Examples include benzoate-based photopolymerization initiators such as ethylhexyl-4- (dimethylamino) benzoate.

  Of the above photopolymerization initiators, oxime ester-based photopolymerization initiators and α-aminoalkylphenone-based photopolymerization initiators are preferred from the viewpoint of excellent photosensitivity. These photopolymerization initiators may be used alone or in combination of two or more. The content of the photopolymerization initiator is not particularly limited, but is preferably 1.0 to 10 parts by mass, and more preferably 2.0 to 10 parts by mass, based on 100 parts by mass of the carboxyl group-containing photosensitive resin (solid content, the same applies hereinafter). -8.0 parts by mass is particularly preferred.

(C) Epoxy compound The epoxy compound increases the crosslink density of the cured product of the photosensitive resin composition, and contributes to obtaining a cured product having sufficient mechanical strength. Examples of the epoxy compound include an epoxy resin. The epoxy resin is not particularly limited, and for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, phenyl aralkyl type epoxy resin, naphthalene type epoxy resin, phenol novolak type epoxy Resin, cresol novolak type epoxy resin, dicyclopentadiene type epoxy resin, adamantane type epoxy resin and the like can be mentioned. 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 preferably 10 to 150 parts by mass, and more preferably 15 to 15 parts by mass, based on 100 parts by mass of the carboxyl group-containing photosensitive resin, from the viewpoint of reliably obtaining a cured product having sufficient mechanical strength. 80 parts by mass is more preferable, and 20 to 40 parts by mass is particularly preferable.

(D) an aliphatic urea compound having a melting point of 100 ° C. to 200 ° C. A photosensitive resin composition containing a carboxyl group-containing photosensitive resin, a photopolymerization initiator, and an epoxy compound has a melting point of 100 ° C. to 200 ° C. By blending the aliphatic urea compound at a temperature of ° C., a cured product having excellent insulation reliability, heat resistance and flexibility and having an excellent matte appearance can be obtained. Each of the above-mentioned effects is achieved by the fact that, in addition to the properties of the aliphatic urea compound itself, the melting point of the aliphatic urea compound is from 100 ° C. to 200 ° C., so that the reactivity between the carboxyl group-containing photosensitive resin and the aliphatic urea compound can be improved. Is considered to be obtained by good.

（式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｒ^６、Ｒ^７は、それぞれ、独立して、炭素数１〜２０個の飽和脂肪族炭化水素基、または少なくとも１つのエチレン性不飽和基を有する炭素数２〜２０個の不飽和脂肪族炭化水素基を意味する。）で表される化合物を挙げることができる。 An aliphatic urea compound is an aliphatic urea compound having no aromatic ring in its chemical structure. Examples of the aliphatic urea compound having a melting point of 100 ° C. to 200 ° C. include an aliphatic urea compound having a cycloaliphatic structure. As the aliphatic urea compound having a cyclic aliphatic structure, the following general formula (1)

(Wherein, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ each independently represent a saturated aliphatic hydrocarbon group having 1 to 20 carbon atoms, or at least one of Which means an unsaturated aliphatic hydrocarbon group having 2 to 20 carbon atoms having an ethylenically unsaturated group.).

Of these, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ are each independently from the viewpoint of further reducing the gloss value of the cured product to further improve the matte appearance. And an aliphatic urea compound of the general formula (1), which is a saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms, is more preferable, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ is more preferably an aliphatic urea compound of the general formula (1) in which each independently represents a saturated aliphatic hydrocarbon group having 1 to 3 carbon atoms, and R ¹ , R ² , R ³ , and R ⁴ In particular, an aliphatic urea compound of the general formula (1) wherein R ⁵ , R ⁶ , and R ⁷ are all methyl groups is preferred. The aliphatic urea compound of the general formula (1) in which R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ are all methyl groups is represented by N ′-[3-[[[ (Dimethylamino) carbonyl] amino] methyl] -3,5,5-trimethylcyclohexyl] -N, N-dimethylurea. The melting point of N ′-[3-[[[(dimethylamino) carbonyl] amino] methyl] -3,5,5-trimethylcyclohexyl] -N, N-dimethylurea is 150 ° C.

Further, the melting point of the aliphatic urea compound is not particularly limited as long as it is in the range of 100 ° C. to 200 ° C., and the reactivity between the carboxyl group-containing photosensitive resin and the aliphatic urea compound is further improved, and From the viewpoint of obtaining insulation reliability and heat resistance, the range of 120 ° C to 180 ° C is preferable, and the range of 130 ° C to 170 ° C is particularly preferable.

  The content of the aliphatic urea compound having a melting point of 100 ° C. to 200 ° C. is not particularly limited, but the lower limit thereof is from the viewpoint of reliably improving the matte appearance and heat resistance. It is preferably 1.0 part by mass, more preferably 4.0 parts by mass, and particularly preferably 6.0 parts by mass from the viewpoint of further improving heat resistance. On the other hand, the upper limit of the content of the aliphatic urea compound having a melting point of 100 ° C. to 200 ° C. is 30 points with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin from the viewpoint of ensuring excellent insulation reliability. A mass part is preferred, 25 mass parts is more preferred, and 17 mass parts is especially preferred.

In the photosensitive resin composition of the present invention, a cured product having a matte appearance can be obtained by blending an aliphatic urea compound having a melting point of 100 ° C to 200 ° C. For example, after the photosensitive resin composition of the present invention is applied, it is dried at 70 ° C. for 20 minutes, irradiated with ultraviolet rays of 400 mJ / cm ² , and thermally cured at 150 ° C. for 60 minutes. The gloss value obtained by measuring the 60-degree specular reflectance of the object surface using a gloss meter is preferably 40% or less. When the gloss value is reduced to 40% or less, a cured product having a more excellent matte appearance can be obtained. The gloss value is preferably as low as possible, for example, more preferably 35% or less, particularly preferably 30% or less.

  In the photosensitive resin composition of the present invention, together with an aliphatic urea compound having a melting point of 100 ° C. to 200 ° C., if necessary, a component having a conventional matting effect, an organic filler and an inorganic filler are used. You may mix.

  Examples of the organic filler include particulate urethane resin (urethane beads), fluororesin, epoxy resin, silicone resin, polyethylene, polypropylene, polyamide, polyimide, polymethyl methacrylate, polybutyl methacrylate, and the like. The average primary particle diameter of the organic filler is preferably from 1 μm to 30 μm, particularly preferably from 2 μm to 10 μm. The compounding amount of the organic filler is, for example, preferably from 1.0 to 30 parts by mass, particularly preferably from 2.0 to 15 parts by mass, per 100 parts by mass of the carboxyl group-containing photosensitive resin.

  Examples of the inorganic filler include particulate silica, talc, clay, mica, magnesium hydroxide, calcium carbonate, magnesium carbonate, and the like. The average primary particle diameter of the inorganic filler is preferably from 0.1 μm to 10 μm, particularly preferably from 1 μm to 5 μm. The compounding amount of the inorganic filler is, for example, preferably from 0.2 parts by mass to 10 parts by mass, particularly preferably from 1.0 part by mass to 5 parts by mass based on 100 parts by mass of the carboxyl group-containing photosensitive resin.

(E) 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 two or more polymerizable double bonds per molecule. The reactive diluent enhances photocuring of the photosensitive resin composition, and contributes to acid resistance, heat resistance, alkali resistance and the like of the photocured product. Examples of the reactive diluent include a monofunctional (meth) acrylate monomer and a difunctional or higher functional (meth) acrylate monomer. Specific examples include 2-hydroxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, diethylene glycol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, and caprolactone-modified (meth) Acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, neopentyl glycol adipate di (meth) Acrylate, neopentyl glycol hydroxypivalate di (meth) acrylate, dicyclopentanyl di (meth) acrylate, ethylene oxide-modified phosphate di (meth) acrylate, allylated cyclohexyl di ( TA) acrylate, isocyanurate di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified Examples include trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, propionic acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and urethane (meth) acrylate. These may be used alone or in combination of two or more.

  The content of the reactive diluent is not particularly limited, but is preferably 5.0 to 50 parts by mass, particularly preferably 10 to 30 parts by mass, per 100 parts by mass of the carboxyl group-containing photosensitive resin.

  In the photosensitive resin composition of the present invention, in addition to the above components (A) to (E), if necessary, other components such as extender, curing accelerator, additive, and colorant , A non-reactive diluent, a flame retardant and the like may be appropriately blended.

  Examples of the extender include aluminum hydroxide, aluminum oxide, barium sulfate, and the like. Examples of the curing accelerator include mercaptobenzoxazal and its derivatives, dicyandiamide (DICY) and its derivatives, melamine and its derivatives, boron trifluoride-amine complex, organic acid hydrazide, diaminomaleonitrile (DAMN) and its derivatives, and guanamine. And its derivatives, amine imides (AI) and polyamines. Examples of the additives include defoamers such as silicone, hydrocarbon, and acrylic, dispersants such as (meth) acrylic polymer, thixotropy-imparting agents, and antioxidants.

  The colorant is not particularly limited, such as a pigment and a dye, and is also not particularly limited, and a white colorant, a blue colorant, a green colorant, a yellow colorant, a purple colorant, a black colorant, an orange colorant, a red colorant, Colorants of any color can be used. Examples of the coloring agent include inorganic coloring agents such as titanium oxide as a white coloring agent, carbon black as a black coloring agent, phthalocyanine green as a green coloring agent, and phthalocyanine blue and lionol blue as blue coloring agents. And organic colorants such as diketopyrrolopyrroles such as chromophthal orange which is an orange colorant.

The flame retardant is for imparting flame retardancy to a cured product of the photosensitive resin composition of the present invention. Examples of the flame retardant include a phosphorus-based flame retardant. Examples of the phosphorus-based flame retardant include tris (chloroethyl) phosphate, tris (2,3-dichloropropyl) phosphate, tris (2-chloropropyl) phosphate, tris (2,3-bromopropyl) phosphate and tris (bromo). Halogen-containing phosphoric acid such as chloropropyl) phosphate, 2,3-dibromopropyl-2,3-chloropropylphosphate, tris (tribromophenyl) phosphate, tris (dibromophenyl) phosphate, and tris (tribromoneopentyl) phosphate Esters; non-halogenated aliphatic phosphates such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, and tributoxyethyl phosphate; triphenyl phosphate; Resyl diphenyl phosphate, dicresyl phenyl phosphate, tricresyl phosphate, trixylenyl phosphate, xylenyl diphenyl phosphate, tris (isopropylphenyl) phosphate, isopropylphenyl diphenyl phosphate, diisopropylphenyl phenyl phosphate, tris (trimethylphenyl) phosphate, Non-halogenated aromatic phosphates such as tris (t-butylphenyl) phosphate, hydroxyphenyldiphenylphosphate, octyldiphenylphosphate; aluminum trisdiethylphosphinate, aluminum trismethylethylphosphinate, aluminum trisdiphenylphosphinate, bisdiethylphosphinate Zinc, bismethylethylphosphinic acid Of phosphinic acids such as lead, zinc bisdiphenylphosphinate, titanyl bisdiethylphosphinate, titanium tetrakisdiethylphosphinate, titanyl bismethylethylphosphinate, titanium tetrakismethylethylphosphinate, titanyl bisdiphenylphosphinate and titanium tetrakisdiphenylphosphinate. Metal salts, phosphine oxides such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, diphenylvinylphosphine oxide, triphenylphosphine oxide, trialkylphosphine oxide, tris (hydroxyalkyl) phosphine oxide and the like And the like. Of these, organic phosphate-based flame retardants are preferred. These may be used alone or in combination of two or more.

  The non-reactive diluent is for adjusting the viscosity, coatability and drying property of the photosensitive resin composition. Non-reactive diluents include, for example, organic solvents. Examples of the organic solvent include ketones such as methyl ethyl ketone, aromatic hydrocarbons such as benzene, toluene and xylene, alcohols such as methanol, ethanol, n-propanol, isopropanol and cyclohexanol, and oils such as cyclohexane and methylcyclohexane. Petroleum solvents such as cyclic hydrocarbons, petroleum ether, petroleum naphtha, cellosolves such as cellosolve and butyl cellosolve, carbitols such as carbitol and butyl carbitol, ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate and carbitol Esters such as tall acetate, butyl carbitol acetate, ethylene glycol acetate and ethyl diglycol acetate can be exemplified. These may be used alone or in combination of two or more.

  The method for producing the above-described photosensitive resin composition of the present invention is not limited to a specific method. For example, after mixing the above-described components at a predetermined ratio, at room temperature (for example, 10 ° C. to 30 ° C.), the three components are mixed. It can be manufactured by kneading or mixing by a kneading means such as a roll, a ball mill, a sand mill, a bead mill, a kneader or the like, or a stirring and mixing means such as a super mixer, a planetary mixer, and a trimix. Before kneading or mixing, preliminary kneading or pre-mixing may be performed as necessary.

  Next, an example of a method for using the above-described photosensitive resin composition of the present invention will be described. Here, a method for forming a solder resist film on a flexible printed wiring board having a circuit pattern formed by etching a copper foil, using a dry film coated with the photosensitive resin composition of the present invention, will be described as an example. explain.

  The dry film includes a support film (for example, a thermoplastic film such as a polyethylene terephthalate film and a polyester film), a solder resist layer applied to the support film, and a cover film (for example, a polyethylene film) for protecting the solder resist layer. , A polypropylene film). After coating the photosensitive resin composition of the present invention on a support film by a known method such as a roller coating method or a bar coater method to form a coating film having a predetermined thickness, the coating film is subjected to a drying treatment. Then, a solder resist layer is formed on the supporting film. Thereafter, a dry film coated with the photosensitive resin composition of the present invention can be produced by laminating a cover film on the formed solder resist layer.

The solder resist layer and the flexible printed wiring board are bonded together while the cover film of the dry film is peeled off to form a solder resist film on the flexible printed wiring board. Thereafter, if necessary, predrying is performed by heating at a temperature of about 100 to 120 ° C. for about 1 to 10 minutes to volatilize a non-reactive diluent (organic solvent) in the photosensitive resin composition. A non-reactive diluent (organic solvent) is volatilized from the resin composition to make the surface of the solder resist film tack-free. A negative film having a light-transmitting pattern other than the land of the circuit pattern is brought into close contact with the formed solder resist film, and ultraviolet light (for example, in a wavelength range of 300 to 400 nm) is irradiated thereon. Thereafter, the solder resist film is developed by removing the non-exposed area corresponding to the land with a diluted alkaline aqueous solution. As a developing method, a spray method, a shower method, or the like is used. As the dilute aqueous alkaline solution to be used, for example, a 0.5 to 5% by mass aqueous sodium carbonate solution is exemplified. After the development, post-curing is performed for 20 to 80 minutes with a dryer of a hot air circulation type at 130 to 170 ° C., so that a solder resist film can be formed on the flexible printed wiring board.

  Next, examples of the present invention will be described, but the present invention is not limited to these examples unless it exceeds the gist.

Examples 1-3, Comparative Examples 1-3
The components shown in Table 1 below were blended in the proportions shown in Table 1 below, and mixed and dispersed at room temperature (about 25 ° C.) using three rolls to obtain Examples 1-3 and Comparative Examples 1-3. Were used to prepare the photosensitive resin compositions to be used. The 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 containing carboxyl group, KAYARAD ZAR-2000: 65% by mass of solid content (resin content), Nippon Kayaku Co., Ltd. KAYARAD ZAR-2000 has at least an epoxy group of an epoxy resin (bisphenol A type epoxy resin). A polybasic acid-modified epoxy acrylate resin having a chemical structure prepared by reacting acrylic acid to obtain an epoxy acrylate and reacting a polybasic acid with a hydroxyl group of the epoxy acrylate.

(B) Photopolymerization initiator IRGACURE 369: 1-benzyl-1- (dimethylamino) propyl-4-morpholinophenyl-ketone, Ciba Specialty Chemicals Co., Ltd. IRGACURE OXE02: Ethanone, 1- [9-ethyl- 6- (2-Methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime), Ciba Specialty Chemicals Co., Ltd. (C) Epoxy compound epicron 850-S: DIC Corporation ( D) Aliphatic urea compound having a melting point of 100 ° C. to 200 ° C. U-Cat3513N: N ′-[3-[[[(dimethylamino) carbonyl] amino] methyl] -3,5,5-trimethylcyclohexyl] -N, N-dimethylurea (melting point 150 ° C), San Apro Co., Ltd. (E) Reactive dilution · EBECRYL8405: Daicel-Cytec Co., Ltd.

Inorganic Filler Syloid ED-5: Grace & Co. Organic Filler RHC-730: Dainichi Seika Kogyo Co., Ltd.

Extender / Heidilite H42M: Showa Denko KK Flame retardant / Exolit OP-935: Clariant Japan Co., Ltd. Curing accelerator / Melamine: Nissan Chemical Co., Ltd./DICY-7: Mitsubishi Chemical Corporation Additives / AC-303: Dispersion Coloring agent, Denka Black: Denka Co., Ltd. Non-reactive diluent, EDGAC: Sanyo Chemical Co., Ltd.

Test piece preparation process for flexibility (flexibility) evaluation (test piece preparation step 1)
A 25 μm-thick polyimide film (Dupont Toray Co., Ltd., “Kapton 100H”) is coated with the photosensitive resin composition prepared as described above by a screen printing method so as to have a DRY film thickness of 20 μm. In the inside, preliminary drying was performed at 70 ° C. for 20 minutes. After the preliminary drying, the applied photosensitive resin composition was irradiated with ultraviolet light (wavelength: 300 to 400 nm) at 400 mJ / cm ² by an exposure apparatus (Oak Seisakusho Co., Ltd., “HMW-680GW”). After the irradiation, post-curing was performed in a BOX furnace at 150 ° C. for 60 minutes, followed by heat curing to obtain a cured coating film, thereby preparing a test piece for evaluating flexibility.

Gross value, insulation reliability, test piece preparation process for heat resistance evaluation (test piece preparation step 2)
A flexible printed wiring board in which a 25 μm-thick polyimide film (Dupont Toray Co., Ltd., “Kapton 100H”) is provided with a comb-shaped circuit pattern having a conductor (copper foil) thickness of 9 μm, a line width of 100 μm, and a space width of 100 μm 3 After the surface treatment with an aqueous solution of sulfuric acid of mass%, the photosensitive resin composition prepared as described above is applied by a screen printing method so that the DRY film thickness on the conductor becomes 20 μm, and the resultant is heated to 70 ° C. in a BOX furnace. For 20 minutes. After the preliminary drying, a negative film having a pattern in which light is transmissive except for the land of the circuit pattern is brought into close contact with the applied photosensitive resin composition, and the exposed film is exposed to an exposure apparatus (Oak Manufacturing Co., Ltd., “HMW-680GW”). UV light (wavelength: 300 to 400 nm) of 400 mJ / cm ² . After the irradiation, development was performed at a spray pressure of 0.1 MPa for 60 seconds using a 1% by mass aqueous solution of sodium carbonate at 30 ° C. After the development, post-curing was performed in a BOX furnace at 150 ° C. for 60 minutes, followed by heat curing to obtain a cured coating film, and a test piece for evaluating a gloss value, insulation reliability, and heat resistance was prepared.

(1) Gloss value (matte appearance)
The surface of the cured coating film of the sample obtained in the test piece preparation step 2 was measured for 60-degree specular reflectance using a gloss meter VG-2000 (Nippon Denshoku Industries Co., Ltd.). It was evaluated that a matte appearance was obtained when the gloss value was 40% or less.

(2) Flexibility (flexibility)
The sample obtained in the test piece preparation step 1 was repeatedly bent 180 ° by goby fold several times, and the occurrence of cracks in the cured coating film at that time was visually observed and observed with a × 200 optical microscope. The number of times that the test was not performed was measured and evaluated according to the following criteria.
◎: No crack occurred even if bending was repeated 5 times or more.
：: No crack was generated even when bending was repeated 2 to 4 times.
Δ: No cracks occurred even after bending once.
×: Cracks occurred after bending was performed once.

(3) Insulation reliability (insulation reliability in the thickness direction (Z-axis direction) of the cured coating film)
Regarding the sample obtained in the test piece preparation step 2, the upper surface of the cured coating film obtained by depositing silver on the cured coating film was connected to the anode, and the conductor (copper foil) of the flexible printed wiring board was connected to the cathode. . Next, 50 V was applied in a thermo-hygrostat at 85 ° C. and 85% humidity, and the resistance value was continuously measured using an ion migration tester (IMV Co., Ltd., “MIG-8600B / 128”). The time at which 50 V was applied was defined as the measurement start time, and the time required for the resistance value to fall below 1.0E + 6 (1.0 × 10 ⁶ ) Ω was measured. This was defined as the dielectric breakdown time, and evaluated according to the following criteria.
：: 1000 hours or more of dielectric breakdown time.
Δ: Breakdown time of 500 hours or more and less than 1000 hours.
X: The dielectric breakdown time was less than 500 hours.

(4) Heat resistance The cured coating film of the sample obtained in the test piece preparation step 2 was immersed in a solder bath at 260 ° C. for 10 seconds according to the test method of JIS C-6481, and then a peeling test using a cellophane tape was performed for one cycle. After repeating this one to three times, the state of the coating film was visually observed and evaluated according to the following criteria.
：: No change was observed in the coating film even after repeating three cycles.
：: A slight change is observed in the coating film after three cycles.
Δ: A change is observed in the coating film after two cycles.
X: Peeling is observed in the coating film after repeating one cycle.

  The evaluation results are shown in Table 1 below.

As shown in Table 1 above, Examples 1 to 3 in which an aliphatic urea compound having a melting point of 150 ° C was blended.
In this case, a photocured product having excellent insulation reliability, heat resistance, and flexibility, and having a reduced gloss value and an excellent matte appearance was obtained. In particular, in Examples 1 and 3, in which the aliphatic urea compound was contained in 15 parts by mass and 7.5 parts by mass, respectively, with respect to 97.5 parts by mass of the carboxyl group-containing photosensitive resin, the heat resistance was further improved. . Further, in Example 2 in which the aliphatic urea compound and the organic filler as the matting agent were used in combination, and in Example 3 in which the aliphatic urea compound and the inorganic filler as the matting agent were used in combination, the gloss value was further reduced. did.

  On the other hand, in Comparative Example 1 in which the aliphatic urea compound having a melting point of 150 ° C. was not blended, the gloss value was large, and a matte appearance could not be obtained. In Comparative Example 1, excellent heat resistance was not obtained. In Comparative Example 2 in which an inorganic filler as a matting agent was blended in place of the aliphatic urea compound, flexibility was not obtained, and excellent insulation reliability and heat resistance were not obtained. In Comparative Example 3, in which an organic filler as a matting agent was blended instead of the aliphatic urea compound, insulation reliability and heat resistance were not obtained.

  The photosensitive resin composition of the present invention is excellent in insulation reliability, heat resistance and flexibility, and has an excellent matte appearance by being mixed with an aliphatic urea compound having a melting point of 100 ° C to 200 ° C. Since a photocured product can be obtained, for example, in the field of an insulating protective film provided on a flexible printed wiring board, in particular, a dry film having a coating film obtained by applying a photosensitive resin composition to a film is applied to the flexible printed wiring board. This is highly useful in the field of forming a protective film such as a solder resist on a flexible printed wiring board.

Claims (9)

  (E) Reaction with (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) an epoxy compound, (D) an aliphatic urea compound having a melting point of 100 ° C to 200 ° C. A photosensitive diluent. The aliphatic urea compound (D) having a melting point of 100 ° C. to 200 ° C. is represented by the following general formula (1)

(Wherein, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ each independently represent a saturated aliphatic hydrocarbon group having 1 to 20 carbon atoms, or at least one of The photosensitive resin composition according to claim 1, wherein the compound is an unsaturated aliphatic hydrocarbon group having 2 to 20 carbon atoms having an ethylenically unsaturated group. The R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ are each independently a saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms. Item 3. The photosensitive resin composition according to Item 2. 4. The photosensitive resin composition according to claim ² , wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ are methyl groups. 5.   (A) 100 parts by mass of the carboxyl group-containing photosensitive resin, wherein the (D) aliphatic urea compound having a melting point of 100 ° C to 200 ° C contains 1.0 to 30 parts by mass. The photosensitive resin composition according to any one of claims 1 to 4, characterized in that: The coated photosensitive resin composition is dried at 70 ° C. for 20 minutes, irradiated with 400 mJ / cm ² ultraviolet light, and thermally cured at 150 ° C. for 60 minutes. The photosensitive resin composition according to any one of claims 1 to 5, wherein a gloss value obtained by measuring a 60-degree specular reflectance using a gloss meter is 40% or less.   The photosensitive resin composition according to any one of claims 1 to 6, wherein the photopolymerization initiator (B) contains an oxime ester compound and / or an α-aminoalkylphenone compound.   A photocured product of the photosensitive resin composition according to claim 1.   A dry film comprising the photosensitive resin composition according to claim 1.