Photosensitive resin composition for inkjet

Abstract

The present invention provides a photosensitive resin composition for inkjet, which is capable of forming a cured product excellent in adhesion to a substrate having a circuit pattern, and in coating properties for inkjet, flame retardancy, and resistance to gold plating, without impairing basic properties such as electrical insulation, etc. The photosensitive resin composition for inkjet contains (A) a (meth)acrylic compound having a weight average molecular weight of 500 or more, (B) a (meth)acrylic compound having a weight average molecular weight of less than 500, (C) a phosphorus-containing flame retardant having a functional group that is cured by active energy rays, (D) an amine-modified (meth)acrylic compound having a functional group that is cured by active energy rays, and (E) a photopolymerization initiator.

Description

TECHNICAL FIELD

[0001] The present application relates to a photosensitive resin composition which is capable of being applied on a substrate such as a printed wiring board using a rigid substrate, a flexible substrate, etc. by an inkjet method, and which has flame retardancy. BACKGROUND

[0002] In the past, when forming an insulating coating on a substrate having a desired circuit pattern (for example, a printed wiring board), after applying a photosensitive resin composition by a screen printing method or the like, pre-drying is performed, a negative film having a pattern which makes the land of the circuit pattern other than the land transparent is adhered to the applied photosensitive resin composition, active energy rays such as ultraviolet rays are irradiated from above, and the non-exposed area corresponding to the land is removed with an aqueous alkali solution, thereby performing development and heat curing treatment (post-treatment) on the coating film of the photosensitive resin composition.

[0003] However, the method of forming the above-described insulating coating on a substrate has many processing steps such as development, and is complicated in work. Therefore, in recent years, it is also performed in such a manner that a photosensitive resin composition is jetted by an inkjet method to a substrate having a desired circuit pattern to form a coating film, and a cured coating film is formed by performing a curing treatment using active energy rays such as laser, ultraviolet rays on the coating film, and further performing a heat curing treatment on the cured coating film to form an insulating coating having a desired pattern.

[0004] As a curable resin composition suitable for the production of a printed wiring board and used for an inkjet method, for example, a curable resin composition containing a bisallylnadic imide compound having a prescribed chemical structure, a bismaleimide compound having a prescribed chemical structure, and a diluent, the viscosity of which is 150 mPa-s or less at 25°C has been proposed (Patent Document 1).

[0005] On the other hand, since a heat generating element such as an electronic component is mounted on a printed wiring board, flame retardancy is sometimes required for the cured coating film of the photosensitive resin composition forming an insulating coating. In order to stably discharge a photosensitive resin composition having flame retardancy by an inkjet method, it is necessary to incorporate a flame retardant having a fine particle diameter, for example, a flame retardant having an average particle diameter of 1 μm or less in the photosensitive resin composition. Therefore, in order to apply a photosensitive resin composition by an inkjet method, a substance which is subjected to a pulverization treatment to achieve fine particle of a powder-shaped flame retardant is sometimes incorporated in the photosensitive resin composition.

[0006] However, even if a pulverization treatment is performed on a powder-shaped flame retardant, it cannot be sufficiently fine-particle, and there is room for improvement in terms of stably discharging a photosensitive resin composition having flame retardancy by an inkjet method.

[0007] In recent years, as electronic devices have become more highly functional, the electronic components connected to printed wiring boards have diversified. Therefore, the versatility of being able to mount a variety of electronic components is sometimes required for printed wiring boards. In order to impart versatility to printed wiring boards, surface treatment such as gold plating treatment is sometimes performed on the surface of the insulating coating film formed on the printed wiring board. Therefore, not only flame retardancy but also gold plating resistance is sometimes required for the cured coating film of the photosensitive resin composition.

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: International Publication No. 2006 / 075654 SUMMARY

[0011] Problems to be Solved by the Invention

[0012] In view of the above circumstances, an object of the present application is to provide a photosensitive resin composition which is capable of forming a cured product that does not impair the basic properties such as adhesion to a substrate having a circuit pattern and electrical insulation, and which has excellent coating properties for inkjet, flame retardancy, and gold plating resistance.

[0013] Means for Solving the Problem

[0014] The gist of the present application is as follows.

[0015] [1] A photosensitive resin composition for inkjet, comprising (A) a (meth)acrylic compound having a weight average molecular weight of 500 or more, (B) a (meth)acrylic compound having a weight average molecular weight of less than 500, (C) a phosphorus-containing flame retardant, (D) an amine-modified (meth)acrylic compound, and (E) a photopolymerization initiator, wherein the (C) phosphorus-containing flame retardant has a functional group that is cured by active energy rays, and the (D) amine-modified (meth)acrylic compound has a functional group that is cured by active energy rays.

[0016] [2] The photosensitive resin composition for inkjet according to [1], wherein the (C) phosphorus-containing flame retardant is in a powder form, and has a solubility of 10 parts by mass or more with respect to 100 parts by mass of the (B) (meth)acrylic compound having a weight average molecular weight of less than 500 at 25°C.

[0017] [3] The photosensitive resin composition for inkjet according to [1] or [2], wherein the (D) amine-modified (meth)acrylic compound is in a liquid state at 25°C and 1 atm.

[0018] [4] The photosensitive resin composition for inkjet according to any one of [1] to [3], wherein the (C) phosphorus-containing flame retardant is a compound having an ethylenic unsaturated bond and / or an oxirane ring.

[0019] [5] The photosensitive resin composition for inkjet according to any one of [1] to [3], wherein the (C) phosphorus-containing flame retardant is a compound having a (meth)acryloyl group or a glycidyl group.

[0020] [6] The photosensitive resin composition for inkjet according to any one of [1] to [5], wherein the (D) amine-modified (meth)acrylic compound is a compound having an ethylenic unsaturated bond and / or an oxirane ring.

[0021] [7] The photosensitive resin composition for inkjet according to any one of [1] to [5], wherein the (D) amine-modified (meth)acrylic compound is a compound having a (meth)acryloyl group or a glycidyl group.

[0022] [8] The photosensitive resin composition for inkjet according to any one of [1] to [7], wherein the (B) (meth)acrylic compound having a weight average molecular weight of less than 500 has a cyclic skeleton.

[0023] [9] The photosensitive resin composition for inkjet according to any one of [1] to [8], wherein the (E) photopolymerization initiator contains phosphorus.

[0024]

[10] A cured product of the photosensitive resin composition for inkjet according to any one of [1] to [9].

[0025]

[11] A printed wiring board comprising the cured product according to

[10] .

[0026] The active energy ray in the above-described mode [1] indicates ultraviolet rays or laser light having a wavelength of 300 to 400 μm. In the above-described mode [2], the (C) phosphorus-containing flame retardant in a powder form has a property of dissolving 10 parts by mass or more with respect to 100 parts by mass of the (B) (meth)acrylic compound having a weight average molecular weight of less than 500 at 25°C, and thus the (C) phosphorus-containing flame retardant has a property of easily dissolving with respect to the (B) (meth)acrylic compound having a weight average molecular weight of less than 500 as a component of the photosensitive resin composition.

[0027] Effects of the Invention

[0028] The photosensitive resin composition of the present application contains (A) a (meth) acrylic compound having a weight average molecular weight of 500 or more, (B) a (meth) acrylic compound having a weight average molecular weight of less than 500, (C) a phosphorus-containing flame retardant, (D) an amine-modified (meth) acrylic compound, and (E) a photopolymerization initiator, wherein the (C) phosphorus-containing flame retardant has a functional group that is cured by active energy rays, and the (D) amine-modified (meth) acrylic compound has a functional group that is cured by active energy rays, whereby the photosensitive resin composition is excellent in coatability by inkjet, and can form a cured product that does not impair the basic properties such as adhesion and electrical insulation to a substrate having a circuit pattern, and is excellent in flame retardancy and gold plating resistance.

[0029] The photosensitive resin composition according to the present application, wherein the (C) phosphorus-containing flame retardant is in a powder form, and has a solubility of 10 parts by mass or more at 25°C with respect to 100 parts by mass of the (B) (meth) acrylic compound having a weight average molecular weight of less than 500, whereby the coatability by inkjet is more excellent, and a cured product that reliably improves the flame retardancy can be formed.

[0030] The photosensitive resin composition according to the present application, wherein the (D) amine-modified (meth) acrylic compound is in a liquid state at 25°C under 1 atm, whereby the coatability by inkjet is more excellent, and a cured product that reliably improves the flame retardancy can be formed.

[0031] The photosensitive resin composition according to the present application, wherein the (C) phosphorus-containing flame retardant is a compound having an ethylenic unsaturated bond and / or an oxirane ring, whereby the coatability by inkjet can be reliably improved, and the gold plating resistance can be reliably improved by curing with active energy rays.

[0032] The photosensitive resin composition according to the present application, wherein the (D) amine-modified (meth) acrylic compound is a compound having an ethylenic unsaturated bond and / or an oxirane ring, whereby the coatability by inkjet can be reliably improved, and the gold plating resistance can be reliably improved by curing with active energy rays.

[0033] The photosensitive resin composition according to the present application, wherein the (B) (meth) acrylic compound having a weight average molecular weight of less than 500 has a cyclic skeleton, whereby the gold plating resistance can be further improved. DETAILED DESCRIPTION

[0034] Next, the photosensitive resin composition of the present application is described in detail below. The photosensitive resin composition of the present application is an inkjet photosensitive resin composition containing (A) a (meth)acrylic compound having a weight average molecular weight of 500 or more, (B) a (meth)acrylic compound having a weight average molecular weight of less than 500, (C) a phosphorus-containing flame retardant, (D) an amine-modified (meth)acrylic compound, and (E) a photopolymerization initiator, (C) the phosphorus-containing flame retardant having a functional group that is cured with active energy rays, and (D) the amine-modified (meth)acrylic compound having a functional group that is cured with active energy rays. The photosensitive resin composition of the present application is capable of forming a cured product that does not impair the basic properties such as adhesion to a substrate having a circuit pattern and electrical insulation, coating properties for inkjet, flame retardancy, and gold plating resistance.

[0035] (A) a (meth)acrylic compound having a weight average molecular weight of 500 or more

[0036] (A) a (meth)acrylic compound having a weight average molecular weight of 500 or more (hereinafter sometimes referred to as "(meth)acrylic compound (A)") is not particularly limited in chemical structure as long as it is a (meth)acrylic compound having a weight average molecular weight of 500 or more. In addition, in the present specification, the "weight average molecular weight" indicates a weight average molecular weight determined at normal temperature by gel permeation chromatography (GPC) and calculated by polystyrene conversion.

[0037] As the (meth)acrylic compound (A), for example, a polymer containing a (meth)acrylic acid-containing monomer, a polymer containing a (meth)acrylic acid ester-containing monomer, a polymer containing a (meth)acrylic acid and a (meth)acrylic acid ester-containing monomer, an epoxy (meth)acrylic ester obtained by reacting a (meth)acrylic acid with an epoxy resin, a urethane (meth)acrylic ester, and the like can be given. Among them, from the viewpoint of reliably improving the coating properties by the inkjet method, a (meth)acrylic ester compound is preferred, and an epoxy (meth)acrylic ester, a urethane (meth)acrylic ester is particularly preferred.

[0038] The epoxy (meth) acrylate can be obtained by reacting (meth) acryl acid with at least a part of the epoxy group of an epoxy resin having one or more epoxy groups in one molecule. The epoxy resin is not particularly limited, and for example, a biphenyl aralkyl type epoxy resin, a phenyl aralkyl type epoxy resin, a biphenyl type epoxy resin, a naphthalene type epoxy resin, a dicyclopentadiene type epoxy resin, a rubber-modified epoxy resin such as a silicone-modified epoxy resin, an ε-caprolactone-modified epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a phenol novolak type epoxy resin, a cresol novolak type epoxy resin, a cyclic aliphatic multifunctional epoxy resin, a glycidyl ester type multifunctional epoxy resin, a glycidyl amine type multifunctional epoxy resin, a heterocyclic type multifunctional epoxy resin, a bisphenol-modified novolak type epoxy resin, a multifunctional modified novolak type epoxy resin, and the like can be given. Two or more of the above-mentioned epoxy resins can be used simultaneously or individually. The epoxy (meth) acrylate as the (meth) acryl compound (A) does not have a free carboxyl group.

[0039] For the urethane (meth) acrylate, for example, a urethane (meth) acrylate obtained by reacting a compound having two or more isocyanate groups in one molecule (polyisocyanate compound) with a compound having two or more hydroxyl groups in one molecule (polyol compound) and (meth) acryl acid can be given.

[0040] The polyisocyanate compound is not particularly limited, and for example, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), methylene diisocyanate (MDI), methylene bis-cyclohexyl isocyanate, trimethyl hexamethylene diisocyanate, hexane diisocyanate, hexamethylamine diisocyanate, methylene bis-cyclohexyl isocyanate, toluene diisocyanate, 1,2-diphenylethane diisocyanate, 1,3-diphenylpropane diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethyl diisocyanate, and the like can be given. Two or more of the above-mentioned polyisocyanate compounds can be used simultaneously or individually.

[0041] The polyol compound is not particularly limited, and examples include aliphatic diols such as ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, neopentyl glycol, 1,6-hexanediol, 2,2-diethyl-1,3-propanediol, 3,3-dimethylolheptane, 2-ethyl-2-butyl-1,3-propanediol, 1,12-dodecanediol, 1,18-octadecanediol, and the like having a carbon number of 2 to 22; olefinic diols such as 2-buten-1,4-diol, 2,6-dimethyl-1-octene-3,8-diol, and the like; alicyclic diols such as 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and the like; aliphatic triols such as glycerol, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,6-hexanetriol, trimethylol ethane, trimethylol propane, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-(hydroxymethyl)pentane, 2,2-bis(hydroxymethyl)-3-butanol, and the like; polyols having four or more hydroxyl groups such as tetramethylolmethane, pentaerythritol, dipentaerythritol, xylitol, and the like. Two or more of the above polyol compounds can be used alone or simultaneously.

[0042] In addition, examples of the urethane (meth)acrylate include a structure obtained by reacting a (meth)acrylic acid with at least one of the epoxy groups of an epoxy resin having one or more epoxy groups in one molecule to obtain an epoxy (meth)acrylate, and then adding a compound having one or more isocyanate groups in one molecule to the resulting hydroxyl group.

[0043] The epoxy resin is not particularly limited, and examples include the same as the above-described epoxy (meth)acrylate, such as a biphenyl aralkyl type epoxy resin, a phenyl aralkyl type epoxy resin, a biphenyl type epoxy resin, a naphthalene type epoxy resin, a dicyclopentadiene type epoxy resin, a rubber-modified epoxy resin such as a silicone-modified epoxy resin, an ε-caprolactone-modified epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a phenol novolak type epoxy resin, a cresol novolak type epoxy resin, a cyclic aliphatic multifunctional epoxy resin, a glycidyl ester type multifunctional epoxy resin, a glycidyl amine type multifunctional epoxy resin, a heterocyclic multifunctional epoxy resin, a bisphenol-modified novolak type epoxy resin, a multifunctional modified novolak type epoxy resin, and the like. Two or more of the above epoxy resins can be used alone or simultaneously.

[0044] The compound having one or more isocyanate groups in one molecule is not particularly limited, and, for example, as described above, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), methylene diisocyanate (MDI), methylene bis-cyclohexyl isocyanate, trimethyl hexamethylene diisocyanate, hexane diisocyanate, hexamethylamine diisocyanate, methylene bis-cyclohexyl isocyanate, toluene diisocyanate, 1, 2-diphenylethane diisocyanate, 1, 3-diphenylpropane diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethyl diisocyanate, and the like can be mentioned. As to the above isocyanate compounds, one kind alone can be used, or two or more kinds can be used simultaneously. Thus, the urethane (meth) acrylate having a structure resulting from the addition reaction of the compound having one or more isocyanate groups in one molecule to the hydroxyl group of the epoxy (meth) acrylate, as the (meth) acryl compound (A), does not have a free carboxyl group.

[0045] As to the above various (meth) acryl compounds (A), one kind alone can be used, or two or more kinds can be used simultaneously.

[0046] The weight average molecular weight of the (meth) acryl compound (A) is not particularly limited as long as it is 500 or more, and, from the viewpoint of further improving the ejection property in the inkjet method, it is preferably 520 or more, more preferably 700 or more, and particularly preferably 1000 or more. On the other hand, from the viewpoint of reliably preventing an increase in the viscosity of the photosensitive resin composition and also obtaining an excellent coatability in the inkjet method, the upper limit of the weight average molecular weight of the (meth) acryl compound (A) is preferably 5000, and particularly preferably 4000. In addition, the number of functional groups of the (meth) acryl compound (A) is not particularly limited, but from the viewpoint of further improving the solder heat resistance and gold plating resistance, it is preferably 1 to 5, and particularly preferably 2 to 4.

[0047] (B) (Meth) acryl compound having a weight average molecular weight of less than 500

[0048] (B) a (meth)acrylic compound having a weight average molecular weight (Mw) of less than 500 (hereinafter sometimes referred to as "(meth)acrylic compound (B)"). The (meth)acrylic compound (B) is not particularly limited as long as it is a (meth)acrylic compound having a weight average molecular weight of less than 500. As the (meth)acrylic compound (B), for example, a monofunctional (meth)acrylate monomer, a difunctional or higher (meth)acrylate monomer, or the like (a (meth)acrylate compound) is exemplified. By incorporating the (meth)acrylic compound (B) in the photosensitive resin composition of the present application, a prescribed amount of the prescribed (C) phosphorus-containing flame retardant described later can be dissolved in the (meth)acrylic compound (B), and thus a photosensitive resin composition excellent in coatability at the time of inkjet can be obtained, and in addition, the photosensitive resin composition can be imparted with flame retardancy. Furthermore, by incorporating the (meth)acrylic compound (B), the viscosity of the photosensitive resin composition at 25°C is reduced, and thus even without incorporating a non-reactive diluent (for example, an organic solvent), the photosensitive resin composition can be used for inkjet.

[0049] The viscosity of the (meth)acrylic compound (B) at 25°C is not particularly limited, and from the viewpoint of further improving the coatability at the time of inkjet and in addition, obtaining excellent bleed resistance, it is preferably 1.0 mPa-s or more and 50 mPa-s or less, and particularly preferably 2.0 mPa-s or more and 30 mPa-s or less.

[0050] As the (meth)acrylic compound (B), for example, monofunctional (meth)acrylate compounds such as benzyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, phenol (meth)acrylate, phenoxyethyl (meth)acrylate, diethylene glycol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, dicyclopentyl di(meth)acrylate, oxirane-modified phosphoric acid di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, isocyanurate di(meth)acrylate, difunctional (meth)acrylate compounds such as trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like, and 3 or more functional (meth)acrylate compounds. Two or more of the above substances can be used alone or simultaneously. Among them, from the viewpoint of further improving the gold plating resistance, a (meth)acrylic compound (B) having a cyclic skeleton is preferred, and a (meth)acrylic compound (B) having an aromatic ring is particularly preferred.

[0051] The content of the (meth)acrylic compound (A) and the (meth)acrylic compound (B) in the photosensitive resin composition is not particularly limited, and from the viewpoint of reliably imparting strength to the cured product of the photosensitive resin composition, 5.0 parts by mass or more of the (meth)acrylic compound (A) is preferably contained relative to 100 parts by mass of the (meth)acrylic compound (B), 10 parts by mass or more is more preferred, and 15 parts by mass or more is particularly preferred. On the other hand, from the viewpoint of reliably imparting flame retardancy and reliably improving the coatability in the inkjet method by dissolving the prescribed (C) phosphorus-containing flame retardant in the (meth)acrylic compound (B), 50 parts by mass or less of the (meth)acrylic compound (A) is preferably contained relative to 100 parts by mass of the (meth)acrylic compound (B), 40 parts by mass or less is more preferred, and 30 parts by mass or less is particularly preferred.

[0052] (C) phosphorus-containing flame retardant

[0053] In the present application, as the phosphorus-containing flame retardant of the component (C), a phosphorus-containing flame retardant having a functional group which is cured by active energy rays (hereinafter sometimes referred to as "phosphorus-containing flame retardant (C)") is used. By compounding the phosphorus-containing flame retardant (C) in the photosensitive resin composition, excellent coatability can be obtained even in the inkjet method, and imparting of gold plating resistance and flame retardancy is facilitated. As the phosphorus-containing flame retardant (C), from the viewpoint of reliably improving the coatability by the inkjet method and further reliably improving the gold plating resistance by curing with active energy rays, a compound containing an olefinic unsaturated bond and / or an oxirane ring (epoxy group) can be cited. As the phosphorus-containing flame retardant (C) containing an olefinic unsaturated bond and / or an oxirane ring, more specifically, a compound having a (meth)acryloyl group or a chain epoxy group or an alicyclic epoxy group can be cited.

[0054] From the viewpoint of reliably obtaining excellent coatability in the inkjet method and reliably imparting flame retardancy to the photosensitive resin composition, the phosphorus-containing flame retardant (C) is preferably in a powder form, and has a solubility of 10 parts by mass or more with respect to 100 parts by mass of the (meth)acrylic compound (B) at 25°C. Further, the phosphorus-containing flame retardant (C) being in a powder form means that the state before being mixed into the photosensitive resin composition of the present application is in a powder form. However, even after the phosphorus-containing flame retardant (C) is compounded into the photosensitive resin composition of the present application, a part of the phosphorus-containing flame retardant (C) remains in a powder state and exists in the photosensitive resin composition of the present application (i.e., another part of the phosphorus-containing flame retardant (C) exists in the photosensitive resin composition of the present application in a dissolved state), and thus it can be confirmed that the state before being mixed into the photosensitive resin composition of the present application is in a powder form even after the phosphorus-containing flame retardant (C) is compounded into the photosensitive resin composition of the present application.

[0055] From the viewpoint of further improving the coatability when the inkjet method is used, the solubility of the phosphorus-containing flame retardant (C) with respect to 100 parts by mass of the (meth)acrylic compound (B) at 25°C is preferably 12 parts by mass or more, and particularly preferably 14 parts by mass or more. On the other hand, the upper limit of the solubility of the phosphorus-containing flame retardant (C) with respect to 100 parts by mass of the (meth)acrylic compound (B) at 25°C is more preferably higher, and for example, 50 parts by mass can be cited. Thus, in the photosensitive resin composition, a part of the phosphorus-containing flame retardant (C) is dissolved, and another part remains in a powder state and is mixed.

[0056] The average particle diameter of the phosphorus-containing flame retardant (C) in a powder form is not particularly limited, and for example, from the viewpoint of dispersibility in the photosensitive resin composition, it is preferably 0.10 μm or more and 3.00 μm or less, and particularly preferably 0.10 μm or more and 1.00 μm or less.

[0057] As specific examples of the phosphorus-containing flame retardant (C) of 10 mass parts or more relative to 100 mass parts of the (meth) acrylic compound (B) at 25°C, which is in the form of a powder, mention can be made of (meth) acryloylmethyl diphenylphosphine oxide, 2-(3,4-epoxycyclohexyl)ethyl diphenylphosphine oxide, 10-(3-glycidyloxypropyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-[2-(3,4-epoxycyclohexyl)ethyl]-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3-glycidyloxypropyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 9,10-dihydro-9-oxa-10-vinyl-10-phosphaphenanthrene-10-oxide, phenylvinylphosphinic acid, and the like. As for the above-mentioned substances, one can be used alone, or two or more can be used simultaneously. Among these, from the viewpoint of more excellent coatability in the inkjet method, and the viewpoint of being able to obtain a cured product of more excellent resistance to gold plating, (meth) acryloylmethyl diphenylphosphine oxide and 10-(3-glycidyloxypropyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are preferred.

[0058] The content of the phosphorus-containing flame retardant (C) is not particularly limited, and from the viewpoint of reliably contributing to the improvement of flame retardancy, the lower limit value of the phosphorus-containing flame retardant (C) relative to 100 mass parts of the (meth) acrylic compound (B) is preferably 5.0 mass parts, more preferably 10 mass parts, and particularly preferably 15 mass parts. On the other hand, from the viewpoint of further improving the coatability using the inkjet method, the upper limit value of the content of the phosphorus-containing flame retardant (C) relative to 100 mass parts of the (meth) acrylic compound (B) is preferably 40 mass parts, more preferably 35 mass parts, and particularly preferably 30 mass parts.

[0059] (D) Amine-modified (meth) acrylic compound

[0060] In the present application, as the amine-modified (meth) acrylic compound of the (D) component, an amine-modified (meth) acrylic compound having a functional group that is cured by active energy rays (hereinafter sometimes referred to as "amine-modified (meth) acrylic compound (D)") is used. By incorporating the amine-modified (meth) acrylic compound (D) in the photosensitive resin composition, excellent coatability is obtained even in the inkjet method, and contributes to imparting resistance to gold plating and flame retardancy. The amine-modified (meth) acrylic compound (D) differs from the (meth) acrylic compound (A) and the (meth) acrylic compound (B) in that it is amine-modified. Therefore, the above-mentioned (meth) acrylic compound (A) and (meth) acrylic compound (B) are not subjected to amine modification.

[0061] As the amine-modified (meth)acrylic compound (D), from the viewpoint of reliably improving the coatability by the inkjet method and reliably improving the gold plating resistance by the use of active energy rays, a compound having an ethylenic unsaturated bond and / or an oxirane ring is preferred. As the amine-modified (meth)acrylic compound (D) having an ethylenic unsaturated bond and / or an oxirane ring, more specifically, a compound having a (meth)acryloyl group or a glycidyl group can be mentioned.

[0062] As the amine-modified (meth)acrylic compound (D), from the viewpoint of reliably obtaining excellent coatability in the inkjet method and reliably imparting flame retardancy to the photosensitive resin composition, an amine-modified (meth)acrylic compound (D) that is liquid at 25°C under 1 atm is preferred. As a product of a specific example of the amine-modified (meth)acrylic compound (D), CN371, CN550, CN551 (all of which are manufactured by Sartomer Company), EBECRYL 3703, EBECRYL 80, EBECRYL 7100 (all of which are manufactured by Daicel-Allnex Ltd.), SP281, SP283, SE1703 (all of which are manufactured by SOLTECH Corporation), and the like can be mentioned.

[0063] The content of the amine-modified (meth)acrylic compound (D) is not particularly limited, and from the viewpoint of reliably contributing to the improvement of the flame retardancy, the lower limit value of the amine-modified (meth)acrylic compound (D) is preferably 1.0 part by mass, more preferably 3.0 parts by mass, and particularly preferably 5.0 parts by mass, relative to 100 parts by mass of the (meth)acrylic compound (B). On the other hand, from the viewpoint of further improving the coatability by the inkjet method, the upper limit value of the content of the amine-modified (meth)acrylic compound (D) is preferably 25 parts by mass, more preferably 20 parts by mass, and particularly preferably 15 parts by mass, relative to 100 parts by mass of the (meth)acrylic compound (B).

[0064] (E) Photopolymerization initiator

[0065] The photopolymerization initiator is not particularly limited, and a publicly known substance can be appropriately used. As the photopolymerization initiator, for example, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-methyl-4'-(methylthio)-2-morpholinobutyrophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4'-bis(diethylamino)benzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, ethyl p-dimethylaminobenzoate, and the like can be mentioned. As to the above-mentioned substances, one can be used alone, or two or more can be used simultaneously. Among the above-mentioned photopolymerization initiators, from the viewpoint of flame retardancy, a photopolymerization initiator having phosphorus is preferred.

[0066] The content of the photopolymerization initiator is not particularly limited, and is preferably 5.0 parts by mass or more and 30 parts by mass or less, and particularly preferably 10 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the (meth)acrylic compound (B).

[0067] In the photosensitive resin composition for inkjet according to the present application, in addition to the above-mentioned components (A) to (E), other components, such as a colorant, various additives, a non-reactive diluent, and the like, can be compounded as necessary.

[0068] The colorant is not particularly limited to a pigment, a dye, or the like. In addition, depending on the color imparted to the cured product of the photosensitive resin composition, the colorant can use a white colorant, a blue colorant, a green colorant, a yellow colorant, a violet colorant, a black colorant, or the like. As to the above-mentioned colorant, for example, inorganic colorants such as titanium oxide as a white colorant, carbon black as a black colorant, phthalocyanine green as a green colorant, phthalocyanine blue as a blue colorant, phthalocyanine, color phthalocyanine such as color phthalocyanine yellow, anthraquinone, and the like can be mentioned.

[0069] Among various additives, for example, antifoaming agents such as silicone-based, hydrocarbon-based, and acrylic-based ones, inorganic fillers such as talc, barium sulfate, alumina, aluminum hydroxide, mica, and silica, organic fillers such as powder urethane resin, (meth)acrylic polymer, vinyl polymer, carboxyl group-containing polymer modifier, and carboxylate, and the like can be mentioned.

[0070] A non-reactive diluent is compounded as needed in order to adjust the viscosity and drying property of the photosensitive resin composition for inkjet. As the non-reactive diluent, for example, an organic solvent can be mentioned. As the organic solvent, for example, ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, alcohols such as methanol, isopropyl alcohol, and cyclohexanol, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, cellulose solvents such as cellosolve and butyl cellosolve, carbitols such as carbitol and butyl carbitol, esters such as ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, diethylene glycol monomethyl ether acetate, and diethylene glycol monoethyl ether acetate, and the like can be mentioned.

[0071] The production method of the photosensitive resin composition for inkjet according to the present application is not limited to a specific method, and for example, after the respective components described above are compounded in prescribed proportions, kneading or mixing can be performed at room temperature using a triple roll, a ball mill, a bead mill, a sand mill, or the like, or a stirring means such as a super mixer or a planetary mixer. In addition, pre-kneading or pre-mixing can be performed as needed before the kneading or mixing.

[0072] Next, an example of the use method of the photosensitive resin composition for inkjet according to the present application will be described. For example, the photosensitive resin composition for inkjet according to the present application can be used to form an insulating coating (for example, a solder resist film) on a substrate (for example, a printed wiring board having a prescribed conductor circuit pattern) by an inkjet printing method. First, the photosensitive resin composition for inkjet according to the present application is applied to a printed wiring board in a desired pattern by an inkjet method (for example, an inkjet method using an inkjet dispenser). After the application, the applied coating film is photocured by laser direct writing using LDI (Laser Direct Imaging) or active energy rays such as ultraviolet rays having a wavelength of 300 to 400 μm. Note that, in the case of photocuring treatment using active energy rays such as ultraviolet rays, the light irradiation amount is, for example, in the range of 100 to 2000 mJ / cm 2 After the photocuring treatment of the coating film, post-curing (heat curing treatment) is performed at 130 to 170°C for 20 to 80 minutes using a hot air circulation type drying machine or the like, whereby a solder resist film having a desired pattern can be formed on the printed wiring board.

[0073] Example

[0074] Next, the embodiments of the present application will be described, and the present application is not limited to the above examples as long as it does not deviate from the gist thereof.

[0075] Examples 1 to 26, Comparative Examples 1 to 6

[0076] Each component shown in Tables 1 to 3 below was compounded in the compounding ratio shown in Tables 1 to 3 below, and they were mixed and dispersed at room temperature using a bead mill, whereby the photosensitive resin composition used in Examples 1 to 26, Comparative Examples 1 to 6 was prepared. The compounding amount of each component shown in Tables 1 to 3 below indicates parts by mass as long as it is not particularly stated. Further, the blank part of the compounding amount in Tables 1 to 3 below indicates that it is not compounded.

[0077] Further, the detailed information of each component in Tables 1 to 3 is as follows.

[0078] (A) (Meth)acrylic compound having a weight average molecular weight of 500 or more

[0079] • EBECRYL 3708, EBECRYL 8405, EBECRYL 8402: Daicel-Allnex Ltd.

[0080] • Miramer PE210, Miramer PE250, Miramer PU210: Miwon Corporation

[0081] (B) (Meth)acrylic compound having a weight average molecular weight of less than 500

[0082] • Viscoat #160, Viscoat #150, IBXA: Osaka Organic Chemical Industry Ltd.

[0083] • Light Ester 1.4BG, Light Ester 2EG: Kyoeisha Chemical Co., Ltd.

[0084] • Aronix M-220: Toagosei Co., Ltd.

[0085] • HDDA: Daicel-Allnex Ltd.

[0086] • Miramer M140: Miwon Corporation

[0087] (C) Phosphorus-containing flame retardant

[0088] • MC-4: 10 to 15 g with respect to 100 g of solubility of (B) (Meth)acrylic compound having a weight average molecular weight of less than 500 at 25°C, Katayama Chemical Industries, Ltd.

[0089] • E-10g: solubility of (meth)acrylic compound having weight average molecular weight of less than 500 at 25°C of 10 to 15 g with respect to 100 g, KATSUMURAI CHEMICAL CO., LTD.

[0090] (D) Amine-modified (meth)acrylic compound

[0091] • EBECRYL 3703: amine-modified bisphenol A type epoxy acrylate, liquid at 25°C, 1 atm, Daicel-Allnex Ltd.

[0092] • CN371: amine-modified di(meth)acrylate (amine value of 136 mgKOH / g), liquid at 25°C, 1 atm, Sartomer Company

[0093] (E) Photopolymerization initiator

[0094] • IRGACURE 907, IRGACURE 369E, LUCIRIN TPO, IRGACURE 819: BASF Corporation

[0095] • Chemcure DETX: Chembridge International

[0096] Colorant

[0097] • LEONARDO BLUE FG-7351: TOYO COLOR Co., Ltd.

[0098] • CROMOPHTHAL YELLOW AGR: CIBA SPECIALTY CHEMICALS

[0099] Additive

[0100] • FLOWLEN G-700: KYOEISHA CHEMICAL CO., LTD.

[0101] • UVX-189: KANBEN KAGAKU CO., LTD.

[0102] • BYK-361N, BYK-168: BYK CHEMICAL JAPAN K.K.

[0103] Non-reactive diluent

[0104] • EDGAC: SHIN-NIPPON OIL CHEMICAL CO., LTD.

[0105] Phosphorus-containing flame retardant not having a functional group curable with active energy rays

[0106] • OP-935: aluminum diethylphosphinate, Clariant Corporation

[0107] • FP-110: Hexaphenoxycyclotriphosphazene, San-Aid Co., Ltd.

[0108] Amine-modified (meth)acrylic compound having no functional group curable with active energy rays

[0109] • PA-100: Polymeric fatty acid polyamide resin, T&K TOKA Co., Ltd.

[0110] • Flamestab NOR 116FF: Hindered amine-based flame retardant, BASF Corporation

[0111] Sample production step

[0112] Substrate: Copper-clad laminate (thickness: 1.6 mm)

[0113] Surface treatment: Polishing with a polishing paste

[0114] Printing method: Inkjet printing (inkjet device: "MJP2013F1-DU", Microcraft Co., Ltd.)

[0115] Dry film thickness: 20 to 23 μm

[0116] Exposure: 1000 mJ / cm2on the coated film 2 • "UB093-5AM", EYE GRAPHICS Co., Ltd.

[0117] Post-curing: BOX-type drying oven 150°C, 60 minutes

[0118] Evaluation items

[0119] (1) Coatability

[0120] A 100 x 100 dot pattern was applied using the above inkjet device, and the substrate after that was observed using a magnifying glass (30 times) to confirm whether or not application equivalent to the pattern had been performed.

[0121] (2) Adhesion

[0122] The adhesion to copper was evaluated based on JIS K 5400 for the sample produced by the above sample production step, and was evaluated in terms of the remaining number of checkers according to the following.

[0123] ◎: 100 / 100

[0124] O: 70 / 100 to 99 / 100

[0125] Δ: 10 / 100 to 69 / 100

[0126] X: 0 / 100 to 9 / 100

[0127] (3) Flame retardancy

[0128] Except for changing the substrate from the copper-clad laminate to a polyimide substrate having a thickness of 25 μm, the dry film thickness was made to reach 20 μm by applying on both sides based on the above sample production procedure, and after forming the cured coating film, evaluation was performed based on the UL94 VTM test standard.

[0129] (4) Electric insulation property

[0130] Except for changing the substrate from the copper-clad laminate to a comb test pattern (line width of 100 μm, line pitch of 100 μm), the cured coating film was formed based on the above sample production procedure, and after applying a direct current of 30 V in an atmosphere of temperature 85°C, humidity 85% for 100 hours, the sample was taken out to the outside of the tank, and the insulation resistance value was measured.

[0131] (5) Gold plating resistance property

[0132] Gold plating was performed on the sample produced by the above sample production procedure so that the nickel layer thickness was 3 to 5 μm, and the gold plating layer thickness was 0.05 μm, and the substrate thereafter was observed using a magnifying glass (30 times), and it was confirmed whether or not gold plating was deposited on the open copper pad.

[0133] ◎: Gold plating layer was formed

[0134] O: Slightly, gold plating layer was not formed

[0135] Δ: Gold plating layer was not formed in part

[0136] X: Gold plating layer was not formed on the entire surface

[0137] The evaluation results are shown in Tables 1, 2, and 3 below.

[0138] [Table 1]

[0139]

[0140] [Table 2]

[0141]

[0142] [Table 3]

[0143]

[0144] From the above Tables 1 and 2, in Examples 1 to 26 of the photosensitive resin composition containing (A) a (meth)acrylic compound having a weight average molecular weight of 500 or more, (B) a (meth)acrylic compound having a weight average molecular weight of less than 500, (C) a phosphorus-containing flame retardant having a functional group that is cured by active energy rays, (D) an amine-modified (meth)acrylic compound having a functional group that is cured by active energy rays, and (E) a photopolymerization initiator for inkjet, the coatability is excellent, and a cured product having excellent adhesion and electrical insulation properties, flame retardancy, and gold plating resistance can be formed. According to Example 3 and Examples 1, 2, 4 to 6, if MC-4, a methacryloylmethyl diphenyl phosphine oxide, is contained as the (C) component phosphorus-containing flame retardant, and CN371, an amine-modified acrylate, is contained as the (D) component amine-modified (meth)acrylic compound, the gold plating resistance is further improved. In particular, according to Example 1 and Examples 13 to 19, if benzyl acrylate, a structure having a cyclic skeleton, is used as the (B) (meth)acrylic compound having a weight average molecular weight of less than 500, the gold plating resistance is further improved.

[0145] On the other hand, according to the above Table 3, in Comparative Example 1 not containing the (D) component amine-modified (meth)acrylic compound, and Comparative Example 2 not containing the (C) component phosphorus-containing flame retardant, the flame retardancy cannot be obtained. In addition, in Comparative Examples 3 and 4 in which the (D) component amine-modified (meth)acrylic compound is replaced with an amine-modified (meth)acrylic compound not having a functional group that is cured by active energy rays, the gold plating resistance or the coatability in the inkjet method cannot be obtained. In addition, in Comparative Examples 5 and 6 in which the (C) component phosphorus-containing flame retardant is replaced with a phosphorus-containing flame retardant not having a functional group that is cured by active energy rays, the gold plating resistance or the coatability in the inkjet method cannot be obtained.

[0146] Industrial applicability

[0147] The photosensitive resin composition of the present application has excellent coatability by the inkjet method, and can form a cured product having excellent adhesion and electrical insulation properties with respect to a circuit pattern, and excellent flame retardancy and gold plating resistance, and thus has high value in the field of forming an insulating coating on a printed wiring board having a desired circuit pattern.

Claims

1. A photosensitive resin composition for inkjet, comprising (A) a (meth) acrylic compound having a weight average molecular weight of 500 or more, (B) a (meth) acrylic compound having a weight average molecular weight of less than 500, (C) a phosphorus-containing flame retardant, (D) an amine-modified (meth) acrylic compound, and (E) a photopolymerization initiator, wherein, The (C) phosphorus-containing flame retardant has a functional group that is cured with active energy rays, and the (D) amine-modified (meth)acrylic compound has a functional group that is cured with active energy rays, The (D) amine-modified (meth)acrylic compound is a compound having an ethylenic unsaturated bond and / or an oxirane ring.

2. The photosensitive resin composition for inkjet according to claim 1, wherein The (C) phosphorus-containing flame retardant is in a powder form, and has a solubility of 10 parts by mass or more with respect to 100 parts by mass of the (B) (meth)acrylic compound having a weight average molecular weight of less than 500 at 25°C.

3. The photosensitive resin composition for inkjet according to claim 1 or 2, wherein, The (D) amine-modified (meth)acrylic compound is in a liquid state at 25°C under 1 atm.

4. The photosensitive resin composition for inkjet according to claim 1 or 2, wherein, The (C) phosphorus-containing flame retardant is a compound having an ethylenic unsaturated bond and / or an oxirane ring.

5. The photosensitive resin composition for inkjet according to claim 1 or 2, wherein The (C) phosphorus-containing flame retardant is a compound having a (meth)acryloyl group or a glycidyl group.

6. The photosensitive resin composition for inkjet according to claim 1 or 2, wherein The (D) amine-modified (meth)acrylic compound is a compound having a (meth)acryloyl group or a glycidyl group.

7. The photosensitive resin composition for inkjet according to claim 1 or 2, wherein The (B) (meth)acrylic compound having a weight average molecular weight of less than 500 has a cyclic skeleton.

8. The photosensitive resin composition for inkjet according to claim 1 or 2, wherein The (E) photopolymerization initiator contains phosphorus.

9. A cured product, which is a cured product of the photosensitive resin composition for inkjet according to any one of claims 1 to 8.

10. A printed wiring board comprising the cured product according to claim 9.

Images