TW201504304A - Photocurable resin composition, cured product of same and printed wiring board - Google Patents

Abstract

The purpose of the present invention is to provide: a photocurable resin composition which is suppressed in the generation of an outgas; a cured product which is obtained by curing this photocurable resin composition; and a printed wiring board which is provided with this cured product. A photocurable resin composition which contains a carboxyl group-containing resin, a compound that has two or more ethylenically unsaturated groups in each molecule, and a photopolymerization initiator that is represented by general formula (I). (In the formula, R represents a structure represented by formula (II); l1 represents an integer of 2-4; and m1 represents an integer of 1 or more).

Description

Photocurable resin composition, cured product thereof, and printed wiring board

The present invention relates to a photocurable resin composition, a cured product thereof, and a printed wiring board provided therewith.

A photocurable composition containing a photopolymerization initiator as a component and hardened by irradiation with an active energy ray such as ultraviolet rays is used for a coating material, a resin insulating layer, and a solder resist because it has advantages such as excellent rapid curing property. A wide range of fields such as pastes for electrode formation (for example, Patent Documents 1 and 2).

When the photocurable composition is thermally cured at the time of photocuring or after the necessity, the components of the photopolymerization initiator or the like are volatilized and vaporized, and the so-called out gas is contaminated. The problem, so ask for its solution. For example, Patent Document 3 discloses a photocurable resin composition containing a complex of onium borate, which is a photocurable composition having little occurrence of outgassing.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2000-214584

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2001-075281

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2005-336314

In recent years, in order to increase the performance of the photocurable composition or to expand the use, it is more desirable to reduce the occurrence of outgassing of the photocurable composition.

Therefore, an object of the present invention is to provide a photocurable resin composition capable of suppressing generation of outgas, a cured product obtained by curing the same, and a printed wiring board having the same.

In view of the above problems and intensive studies, the present inventors have found that the above problems can be solved by using a specific photopolymerization initiator, and the present invention has been completed.

In other words, the photocurable resin composition of the present invention contains a carboxyl group-containing resin, a compound having two or more ethylenically unsaturated groups in the molecule, and photopolymerization represented by the following general formula (I). Starting agent

(wherein R represents a structure represented by the following formula (II), and l ₁ represents an integer of 2 to 4, and m ₁ represents an integer of 1 or more),

The photocurable resin composition of the present invention preferably further contains a thermosetting component.

In the photocurable resin composition of the present invention, the thermosetting component is preferably an epoxy resin.

The photocurable resin composition of the present invention is preferably used for forming a resist.

The cured product of the present invention is characterized in that the photocurable resin composition is cured.

The printed wiring board of the present invention is characterized in that the cured product is provided.

According to the present invention, it is possible to provide a photocurable resin composition capable of suppressing the occurrence of outgassing, a cured product obtained by curing the same, and a printed wiring board having the same.

Fig. 1 is a graph showing a heating decrement curve obtained by simultaneous measurement of differential photothermal-thermal weight (TG/DTA measurement) of a photopolymerization initiator used in Reference Example. The horizontal axis represents the temperature (Cel: Celsius temperature), and the vertical axis represents the reduction ratio (%) of the thermal weight.

Hereinafter, the photocurable resin composition of the present invention will be described in detail.

[Carboxyl group-containing resin]

The photocurable resin composition of the present invention contains a carboxyl group-containing resin. The photocurable resin composition can be made into an alkali-curable photocurable resin composition by containing a carboxyl group-containing resin. The carboxyl group-containing resin is not particularly limited, and can be used as a conventional carboxyl group-containing resin used for a solder resist or a photocurable resin composition for an interlayer insulating layer.

Further, from the viewpoint of photocurability or developability, it is preferable to have an ethylenically unsaturated bond in the molecule in addition to a carboxyl group, but it may also be a carboxyl group-containing resin having no ethylenically unsaturated double bond. . When the carboxyl group-containing resin does not have an ethylenically unsaturated bond, a compound having two or more ethylenically unsaturated groups in the molecule (photoreactive monomer) is used in combination in order to impart photocurability to the composition. . As the ethylenically unsaturated double bond, acrylic acid or methacrylic acid or a derivative derived therefrom is preferred.

The carboxyl group-containing resin having a carboxyl group in the molecule and not containing an ethylenically unsaturated bond in the molecule can be exemplified as follows: (1) by using an unsaturated carboxylic acid (for example, acrylic acid, methacrylic acid, etc.) with a compound having an unsaturated double bond (for example, styrene, α-methylstyrene, low-order alkyl (meth)acrylic acid a carboxyl group-containing resin obtained by copolymerization of an ester, isobutylene or the like; (2) an epoxy group of a copolymer of a compound having an unsaturated double bond and glycidyl (meth) acrylate, and one molecule having An organic acid having one carboxyl group and having no ethylenically unsaturated bond (for example, an alkyl carboxylic acid having 2 to 17 carbon atoms or an alkyl carboxylic acid containing an aromatic group) is reacted, and the resulting secondary hydroxyl group is further reacted. a carboxyl group-containing resin obtained by reacting with a saturated or unsaturated polybasic acid anhydride; (3) a hydroxyl group-containing polymer (for example, an olefin-based hydroxyl group-containing polymer, an acrylic polyol, a rubber-based polyol, or a polyethylene) a carboxyl group-containing resin obtained by reacting an aldehyde, a styrene allyl resin, a cellulose or the like with a saturated or unsaturated polybasic acid anhydride; (4) a diepoxide compound (for example, a bisphenol A type epoxy resin) , bisphenol F type epoxy resin, bisphenol S type epoxy resin, brominated bisphenol A type epoxy tree , hydrogenated bisphenol A type epoxy resin, biphenol type epoxy resin, bisphenol type epoxy resin, etc.) and dicarboxylic acid (for example, oxalic acid, malonic acid, succinic acid, phthalic acid, isophthalic acid) a reaction product of dicarboxylic acid or the like, a carboxyl group-containing resin obtained by reacting with a saturated or unsaturated polybasic acid anhydride; and, (5) a difunctional epoxy compound and a bisphenol (for example, bisphenol A, bisphenol) A reaction product of F or the like, a carboxyl group-containing resin obtained by reacting with a saturated or unsaturated polybasic acid anhydride, or the like.

Further, as the carboxyl group-containing photosensitive prepolymer having a carboxyl group and an intramolecular ethylenically unsaturated bond in the molecule, for example, (1) a polyfunctional epoxy having at least two epoxy groups in one molecule can be exemplified as follows: a hydroxyl group formed by reacting a compound (for example, a novolac type epoxy resin or the like) with an unsaturated monocarboxylic acid (for example, (meth)acrylic acid, etc.), and a saturated or unsaturated polybasic acid anhydride (for example, hexahydrophthalic acid) a carboxyl group-containing photosensitive prepolymer obtained after the reaction of an acid anhydride or tetrahydrophthalic anhydride; (2) a polyfunctional epoxy compound having at least two epoxy groups in one molecule (for example, a phenol type) An epoxy resin or the like, a compound having a reactive group other than a monocarboxylic acid (for example, (meth)acrylic acid) and an alcoholic hydroxyl group reactive with an epoxy group in one molecule (for example, nonylphenol, etc.) And / more preferably, a compound having at least one alcoholic hydroxyl group in one molecule and one reactive group other than the alcoholic hydroxyl group which reacts with an epoxy group (for example, p-hydroxyphenylethanol) is further reacted and saturated. Or an unsaturated polybasic acid anhydride (for example, hexahydrophthalic anhydride or tetrahydrophthalic anhydride) The obtained carboxyl group-containing photosensitive prepolymer; (3) an unsaturated carboxylic acid (for example, (meth)acrylic acid or maleic acid, etc.) and a compound having an ethylenically unsaturated double bond (for example, A a part of a carboxyl group of a copolymer of a (meth) acrylate or the like, and a compound having one epoxy group and an ethylenically unsaturated double bond in one molecule (for example, glycidyl (meth) acrylate, etc.) a carboxyl group-containing photosensitive prepolymer obtained after the reaction; (4) an unsaturated carboxylic acid (for example, (meth)acrylic acid or maleic acid, etc.) and a compound having an ethylenically unsaturated double bond ( For example, A a copolymer of a base (meth) acrylate or the like, which is reacted with a compound having one epoxy group and an ethylenically unsaturated double bond in one molecule (for example, glycidyl (meth) acrylate, etc.), and then a carboxyl group-containing photosensitive prepolymer obtained by reacting a generated hydroxyl group with a saturated or unsaturated polybasic acid anhydride (for example, hexahydrophthalic anhydride or tetrahydrophthalic anhydride); and, (5) a copolymer of an unsaturated diprotic anhydride (for example, maleic anhydride or the like) with a compound having an ethylenically unsaturated double bond (for example, methyl (meth) acrylate, etc.), and a hydroxyalkyl group (methyl) A carboxyl group-containing photosensitive prepolymer obtained by reacting an acrylate (for example, 2-hydroxyethyl (meth) acrylate or the like).

Further, the polyfunctional epoxy resin used for the synthesis of the above resin is a bisphenol A structure, a bisphenol F structure, a biphenol structure, a biphenol novolac structure, or a bisxylenol structure, and particularly has a biphenylphenol phenol structure. When the compound and the hydride thereof are used, the cured product of the photocurable composition is preferably low in warpage and bending resistance.

Here, the term "(meth)acrylate" is generally referred to as acrylate, methacrylate, and the like, and the following similar expressions are also the same.

Further, the acid value of the carboxyl group-containing resin is preferably in the range of 20 to 200 mgKOH/g, and more preferably in the range of 40 to 150 mgKOH/g. When the acid value of the carboxyl group-containing resin is 20 mgKOH/g or more, the adhesion of the coating film is good, and in the case of the photocurable resin composition, the alkali liquid developability is superior. Moreover, when the acid value is 200 mgKOH/g or less, the dissolution of the exposed portion due to the developer can be suppressed, and the line is not caused. Further, it is thinner than necessary, and it is possible to suppress the exposed portion and the unexposed portion from being dissolved and peeled off by the developer without distinction, and thus it is easy to obtain a normal resist pattern drawing.

The weight average molecular weight of the carboxyl group-containing resin varies depending on the resin skeleton, but is generally preferably 2,000 to 150,000. When the weight average molecular weight is 2,000 or more, the non-stick property is excellent, and the moisture resistance of the coating film after exposure is good, and no film reduction occurs during development, so the resolution is good. Moreover, when the weight average molecular weight is 150,000 or less, it is excellent in developability, and storage stability is also excellent. It is preferably 5,000 to 100,000.

[Compound having two or more ethylenically unsaturated groups in the molecule]

The photocurable resin composition of the present invention contains a compound (photoreactive monomer) having two or more ethylenically unsaturated groups in the molecule. The compound having two or more ethylenically unsaturated groups in the molecule is photocured by irradiation with an active energy ray, and then contributes to insolubilization or insolubilization of the carboxyl group-containing resin in the aqueous alkali solution. As the photoreactive monomer, a diluent which is a photocurable resin composition can also be used.

As the compound which can be used as the above photoreactive monomer, for example, a conventional polyester (meth) acrylate, a polyether (meth) acrylate, a urethane (meth) acrylate, or a carbonate (for example) can be used. Methyl) acrylate, epoxy (meth) acrylate, and the like. Specific examples thereof include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxy methacrylate. Diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, propylene glycol, diethylene glycol, etc.; N,N-dimethyl methacrylate, N-hydroxyl Acrylamides such as acrylamide, N,N-dimethylaminopropylpropenylamine; N,N-dimethylaminoethyl acrylate, N,N-dimethylaminopropyl Aminoalkyl acrylates such as acrylates; polyols such as hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, cis-hydroxyethyl isocyanurate or the like Multivalent acrylates such as adducts, propylene oxide adducts, or ε-caprolactone adducts; phenoxy acrylates, bisphenol A diacrylates, and phenolic epoxys thereof a polyvalent acrylate such as an ethane adduct or a propylene oxide adduct; glycerol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, triglycidyl isocyanurate a polyvalent acrylate of a glycidyl ether; and not limited to the above, a polyether polyol, a polycarbonate diol, a hydroxyl terminated polybutadiene, a polyether polyol, etc. Acrylated directly, or by a diisocyanate to the esterification of acrylic urethane acrylate and melamine acrylate, and / or the like corresponding to each of acrylates of the above acrylate.

Further, the following resin may be used as a photosensitive monomer: an epoxy acrylate resin obtained by reacting a polyfunctional epoxy resin such as a cresol novolac epoxy resin with acrylic acid, or the epoxy An epoxy urethane acrylate compound obtained by reacting a hydroxyl group of an acrylate resin with a hydroxy acrylate such as pentaerythritol triacrylate or a diisocyanate compound such as isophorone diisocyanate. Such an epoxy acrylate-based resin does not cause stickiness (touch dryness) Reduced and improved hardenability.

In particular, in the present invention, polyvalent acrylates such as polyhydric alcohols or such ethylene oxide adducts, propylene oxide adducts, or ε-caprolactone adducts, or phenols are used. Polyvalent acrylates such as ethylene oxide adducts or propylene oxide adducts, and (meth) acrylates containing urethane oligomers, which are low in warpage and bendability From the viewpoint, it can be suitably used.

The photoreactive single system may be used singly or in combination of two or more. The amount of the photoreactive monomer to be blended is preferably from 1 to 30% by mass, more preferably from 2 to 20% by mass, particularly preferably from 5 to 15% by mass, based on the solid content of the photocurable resin composition. . When the content is 30% by mass or less, adhesion of the surface is not caused, and the dryness of the touch is good. In addition, when it is 1% by mass or more, sufficient photocurability can be obtained at the time of exposure, and pattern formability will be good.

[Photopolymerization initiator]

Moreover, the photocurable resin composition of the present invention contains the photopolymerization initiator represented by the following general formula (I).

(In the formula, R represents a structure represented by the following formula (II), and l ₁ represents an integer of 2 to 4, and m ₁ represents an integer of 1 or more)

The l ₁ in the above general formula (I) is preferably 2 or 4; the m ₁ is preferably 1 to 5, more preferably 1 to 3, and particularly preferably 1.

The photopolymerization initiator represented by the above general formula (I) is preferably liquid at room temperature. Here, the term "liquid at room temperature" means that a sample is placed in a test tube having an inner diameter of 30 mm at a temperature of 10 to 40 ° C to a height of 55 mm and the test tube is horizontally passed from the bottom to the bottom. The 85mm portion is within 90 seconds.

The photopolymerization initiator represented by the above general formula (I) is preferably a 5% reduction temperature of 260 ° C or higher. Further, the upper limit is preferably 500 ° C or lower. In the present specification, the 5% reduction temperature refers to a temperature at which the thermal weight is reduced by 5% in the heating loss curve obtained by simultaneous measurement of differential heat-heat weight (TG/DTA measurement) (measurement condition: 10 °C/min).

As an example of the photopolymerization initiator represented by the above general formula (I), for example, polyethylene glycol (200) bis (β-4-[4-(2-dimethylamino-2-phenyl) group) Butyl phenyl] piperidine ) Propionate and the like.

The chemical formula of a specific example of the photopolymerization initiator represented by the above general formula (I) is described. However, the present invention is not limited by the following compounds.

(wherein n represents an integer of 1 or more).

As an example of a commercial product of the photopolymerization initiator represented by the above general formula (I), Omnipol 910, Omnipol 9210, Omnipol 9220, etc., manufactured by IHT Co., Ltd., can be exemplified.

The photopolymerization initiators of the above formula (I) may be used singly or in combination of two or more. The blending amount of the photopolymerization initiator represented by the above formula (I) is preferably from 0.01 to 15% by mass, and more preferably from 0.1 to 15% by mass, based on the solid content of the photocurable resin composition. When it is 15 mass% or less, the coating film formation will be good. In addition, when it is 0.01% by mass or more, sufficient photocurability can be obtained, and pattern formability will be good.

(thermosetting component)

In the photocurable resin composition of the present invention, a thermosetting component may be added in order to impart heat resistance. The thermosetting component used in the present invention may, for example, be a blocked isocyanate compound, an amine resin, a maleimide compound, or a benzo compound. A conventional thermosetting resin such as a resin, a carbodiimide resin, a cyclic carbonate compound, a polyfunctional epoxy compound, a polyfunctional oxetane compound, or an episulfide resin. Among these, a thermosetting component which is preferably one of a plurality of cyclic ether groups and a cyclic thioether group (hereinafter, simply referred to as a cyclic (thio)ether group) in one molecule is used. Hardening ingredients. The thermosetting component having such a cyclic (thio)ether group is commercially available in a variety of types, and various properties can be imparted depending on the structure.

A thermosetting component having a plurality of cyclic (thio)ether groups in the molecule, which is a cyclic ether group having two or more three, four or five-membered rings or a cyclic thioether group in the molecule. The compound of the two types of the group may, for example, be a compound having a plurality of epoxy groups in the molecule, that is, a polyfunctional epoxy compound; a compound having a plurality of oxetanyl groups in the molecule, that is, a polyfunctional oxy compound. A cyclobutane compound; a compound having a plurality of thioether groups in the molecule, that is, an episulfide resin or the like.

The polyfunctional epoxy compound is a polyfunctional epoxy compound having two or more epoxy groups (oxirane rings) in one molecule, or a resin obtained by polymerizing the polyfunctional epoxy compound. Examples of the polyfunctional epoxy compound include epoxidized vegetable oil; bisphenol A type epoxy resin; hydroquinone type epoxy resin, bisphenol type epoxy resin, thioether type epoxy resin; and brominated epoxy resin. ; phenolic epoxy resin; phenolic phenolic epoxy resin; bisphenol F epoxy resin; hydrogenated bisphenol A epoxy resin; glycidylamine epoxy resin; Ring epoxy resin; trihydroxyphenylmethane type epoxy resin; dixylenol type or biphenol type epoxy resin or a mixture thereof; bisphenol S type epoxy resin; bisphenol A phenolic type epoxy resin ; tetraphenylolethane type epoxy resin; heterocyclic epoxy resin; diglycidyl phthalate resin; tetraglycidyl xylyl ethane resin; naphthalene-containing epoxy tree Lipid; epoxy resin having a dicyclopentadiene skeleton; glycidyl methacrylate copolymerized epoxy resin; copolymerized epoxy resin of cyclohexane maleimide and glycidyl methacrylate; The oxygen-modified polybutadiene rubber derivative, the CTBN modified epoxy resin, and the like are not limited thereto. These epoxy resins may be used alone or in combination of two or more. Among these, a bisphenol type epoxy resin is particularly preferable.

As the above polyfunctional oxetane compound, in addition to bis[(3-methyl-3-oxetanylmethoxy)methyl]ether, bis[(3-ethyl-3-oxetan) Alkyloxy)methyl]ether, 1,4-bis[(3-methyl-3-oxetanylmethoxy)methyl]benzene, 1,4-bis[(3-ethyl-) 3-oxetanyl methoxy)methyl]benzene, (3-methyl-3-oxetanyl) methacrylate, (3-ethyl-3-oxetan) Acrylate, (3-methyl-3-oxetane) methacrylate, (3-ethyl-3-oxetane) methacrylate or such oligomers or copolymers Examples of the polyfunctional oxetane such as a substance include oxetane, phenol resin, poly(p-hydroxystyrene), cardo bisphenol, calixarene, and resorcinol. An ether compound of a resin having a hydroxyl group such as a calixarene or a sesquioxane or the like. Other examples thereof include a copolymer of an oxetane ring-unsaturated monomer and an alkyl (meth) acrylate.

Examples of the episulfide resin having a plurality of cyclic thioether groups in the above-mentioned molecule include YL7000 (bisphenol A type episulfide resin) manufactured by Mitsubishi Chemical Corporation, and YSLV-120TE manufactured by Tosho Kasei Co., Ltd., and the like. Further, an episulfide resin in which an oxygen atom of an epoxy group of a novolac type epoxy resin is substituted with a sulfur atom or the like can be used by the same synthesis method.

Moreover, in addition to the above-mentioned thermosetting component, the photocurable resin composition of the present invention may be a thermosetting component such as an amine resin such as a melamine derivative or a benzoguanamine derivative. Examples of such a thermosetting component include a methylol melamine compound, a methylol benzoguanamine compound, a methylol glycoluril compound, a methylol urea compound, an alkoxymethylated melamine compound, and the like. An alkoxymethylated benzoguanamine compound, an alkoxymethylated glycoluril compound, an alkoxymethylated urea compound, or the like. The type of the alkoxymethyl group is not particularly limited, and examples thereof include a methoxymethyl group, an ethoxymethyl group, a propoxymethyl group, and a butoxymethyl group. In particular, a melamine derivative having a concentration of 0.2% or less of a formalin having a suitable human body or environment is preferred. The thermosetting component may be used singly or in combination of two or more. Moreover, when it is used as a solder resist, it is preferable to mix the said thermosetting component.

(other ingredients)

In the photocurable resin composition of the present invention, conventional additives other than the above components may be blended as long as the effects of the present invention are not impaired. Examples of the additive include a thermal polymerization inhibitor, a UV absorber, a decane coupling agent, a plasticizer, a flame retardant, an antistatic agent, an antiaging agent, an antibacterial, an antifungal agent, an antifoaming agent, a leveling agent, and a filler. A tackifier, a tackifier, a shake imparting agent, a colorant, a photopolymerization initiator other than the above, a photoinitiating aid, a sensitizer, and the like. A solvent may also be used in the case of coating, drying, or photohardening on the surface of the substrate like a solder resist.

(Other photopolymerization initiators)

The photocurable resin composition of the present invention may further contain a photopolymerization initiator other than the above photopolymerization initiator. Examples of the other photopolymerization initiator include an oxime ester photopolymerization initiator, an alkylphenone photopolymerization initiator, a mercaptophosphine oxide photopolymerization initiator, and a titanocene photopolymerization. Starter and the like.

As the oxime ester photopolymerization initiator, CGI-325, Irgacure OXE01, Irgacure OXE02, manufactured by BASF Japan Co., Ltd., N-1919 manufactured by ADEKA Co., Ltd., and the like can be exemplified.

In addition, a photopolymerization initiator having two oxime ester groups in the molecule can be suitably used. Specifically, an oxime ester compound having the carbazole structure represented by the following general formula (2) can be exemplified.

(wherein X represents a hydrogen atom, an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a phenyl group, or a phenyl group (which is an alkyl group having a carbon number of 1 to 17 and carbon) a group of 1 to 8 alkoxy groups, an amine group, an alkylamino group having a carbon number of 1 to 8 or a dialkylamino group, and a naphthyl group (having a carbon number of 1 to 17) An alkyl group, an alkoxy group having 1 to 8 carbon atoms, an amine group, an alkylamino group having a carbon number of 1 to 8 or a dialkylamino group; wherein Y and Z are each represented as a hydrogen atom; Alkyl number, carbon number of 1 to 17 carbon atoms 1 to 8 alkoxy group, halogen group, phenyl group, phenyl group (by an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an amine group, and a carbon number of 1 to 8) a substituted alkylamino or dialkylamino group), naphthyl (by an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an amine group, a carbon number a substituent of an alkylamino group or a dialkylamino group of an alkyl group of 1 to 8, a mercapto group, a pyridyl group, a benzofuranyl group, a benzothienyl group; and an Ar system represents an alkylene group having a carbon number of 1 to 10 , vinyl, phenyl, phenyl, exopyridyl, naphthyl, thienyl, thiol, thienyl, furanyl, 2,5-pyrrole-diyl, 4,4' -茋-diyl, 4,2'-styrene-diyl; n is an integer of 0 or 1)

In particular, in the above formula, X and Y are each a methyl group or an ethyl group, Z is a methyl group or a phenyl group, n is 0, and Ar is an oxime ester group of a stretching phenyl group, a stretching naphthyl group, a thienyl group or a thienyl group. A photopolymerization initiator is preferred.

The oxime ester photopolymerization initiator may be used singly or in combination of two or more. The blending amount in the case of using a phthalic ester-based photopolymerization initiator is preferably from 0.1 to 25% by mass, and more preferably from 5 to 15% by mass, based on the solid content of the photocurable resin composition. When it is 25% by mass or less, the coating film formation will be good. Moreover, when it is 0.1 mass % or more, sufficient photocurability can be obtained, and pattern formation property will be favorable.

The alkylphenone-based photopolymerization initiator may, for example, be a benzyldimethylketal photopolymerization such as 2,2-dimethoxy-1,2-diphenylethane-1-one. Starting agent; 1-hydroxy-cyclohexane-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)- Phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propyl Α-hydroxyalkylphenone photopolymerization initiator such as mercapto)-benzyl]phenyl}-2-methyl-propan-1-one; 2-methyl-1-[4-(methyl sulfide) Phenyl]-2-morpholinylacetone-1, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butan-1-one, 2-( Dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-ythyl)phenyl]-1-butanone, N,N-dimethyl An α-aminoacetophenone photopolymerization initiator such as aminoacetophenone. As a commercial item of the benzyl dimethyl ketal-based photopolymerization initiator, Irgacure 651 manufactured by BASF Japan Co., Ltd., etc. can be mentioned. As a commercial item of the α-hydroxyalkylphenone-based photopolymerization initiator, Irgacure 184, Darocur 1173, Irgacure 2959, Irgacure 127, etc., manufactured by BASF Japan Co., Ltd., may be mentioned. As a commercial item of the α-amino acetophenone-based photopolymerization initiator, Irgacure 907, Irgacure 369, Irgacure 379, etc. by BASF Japan Co., Ltd. are mentioned.

The mercaptophosphine oxide photopolymerization initiator may, for example, be 2,4,6-trimethylbenzimidyldiphenylphosphine oxide or bis(2,4,6-trimethylbenzhydrazide). Phenylphosphine oxide, bis(2,6-dimethoxybenzylidene)-2,4,4-trimethyl-pentylphosphine oxide, and the like. As a commercial item, Lucirin TPO, Irgacure 819, etc. by BASF Japan company are mentioned.

As the titanocene-based photopolymerization initiator, bis(cyclopentadienyl)-di-phenyl-titanium, bis(cyclopentadienyl)-di-chloro-titanium, bis(cyclopentane) can be exemplified. Alkenyl)-bis(2,3,4,5,6pentafluorophenyl)titanium, bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyrrol-1-yl)benzene Base) titanium and the like. As a commercial item, Irgacure 784 by BASF Japan company, etc. are mentioned.

Alkylphenone photopolymerization initiator, mercaptophosphine oxide system The photopolymerization initiator and the titanocene-based photopolymerization initiator may be used singly or in combination of two or more. The amount of the photopolymerization initiator to be used in the photocurable resin composition is preferably 2 to 25% by mass, and more preferably 5 to 15% by mass, based on the solid content. When it is 25% by mass or less, the coating film formation will be good. In addition, when it is 2% by mass or more, sufficient photocurability is obtained and pattern formability is also excellent.

(filler)

The photocurable resin composition of the present invention may further contain a filler (inorganic filler). The filler is used to suppress the hardening shrinkage of the cured product of the photocurable resin composition and to improve the properties such as adhesion and hardness. Examples of the filler include barium sulfate, amorphous vermiculite, molten vermiculite, globular vermiculite, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, tantalum nitride, aluminum nitride, and the like. Boron nitride, Neuburg Siliceous Earth, and the like.

The average particle diameter (D50) of the filler is preferably 1 μm or less, more preferably 0.7 μm or less, and still more preferably 0.5 μm or less. When the average particle diameter exceeds 1 μm, the photocurable resin composition is cloudy and turbid, and it is not suitable depending on the use. The average particle diameter (D50) can be measured by a laser diffraction/scattering method. When the average particle diameter is within the above range, the refractive index will approach the resin component and the permeability will be improved.

(solvent)

The photocurable resin composition of the present invention may contain an organic solvent in order to adjust the viscosity of the composition. As the organic solvent, as long as it is a photopolymerization initiator which can dissolve the present invention, a conventionally used type can be used. For example, toluene, xylene, ethyl acetate, butyl acetate, methanol, ethanol, isopropanol, isobutanol, 1-butanol, diacetone alcohol, ethylene glycol monobutyl ether, propylene glycol monoethyl ether, propylene glycol single Methyl ether acetate, terpineol, methyl ethyl ketone, carbitol, carbitol acetate, butyl carbitol, butyl carbitol acetate, and the like. The solvent may be used singly or in combination of two or more.

The photocurable resin composition of the present invention is applied to a substrate or the like by, for example, the following coating method, and then subjected to ultraviolet irradiation, preferably at a wavelength of 10 to 400 nm, preferably 250 to 400 nm. hardening.

Examples of the ultraviolet light irradiation source include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a xenon lamp or a metal halide lamp, a laser, a UV-LED, and the like.

The coating method can be any method such as a dip coating method, a flow coating method, a roll coating method, a bar coating method, a screen printing method, a curtain coating method, a gravure coating method, or a lithography method. .

The photocurable resin composition of the present invention is preferably a solder resist. The solder resist is characterized in that the photocurable resin composition of the present invention is coated and cured on a substrate.

A conventional method can also be applied to the method of coating and hardening the photocurable resin composition for a solder resist. For example, the method can be as follows. If necessary, it is diluted by a solvent to adjust the viscosity suitable for the coating method, and this is formed on a printed wiring board on which a loop is formed, for example, by screen printing, curtain coating, spray coating, roll coating. The coating is carried out by a method such as a method, and a non-stick coating film can be formed by volatilizing and drying the organic solvent contained in the composition at a temperature of, for example, about 60 to 100 °C. Thereafter, the active energy ray such as laser light is directly irradiated as in the form of a pattern, or is formed by a pattern mask and selectively exposed to ultraviolet light to be cured. When the photocurable resin composition is in the case of an alkali-developing type, the unexposed portion is developed by a dilute aqueous alkali solution to form a resist pattern. Further, as desired, a cured film (cured material) can be formed by heat curing or final hardening (true hardening) after irradiation with ultraviolet rays.

The photocurable resin composition of the present invention can be suitably used for the formation of a resist agent such as a solder resist, an etching resist, a plating resist, or the like. Further, it can be used for an interlayer insulating layer for a printed wiring board, a conductive paste for forming a plasma of a plasma display panel or a touch panel, and the like. Further, the photocurable resin composition of the present invention may be used in the form of a dry film which has a photocurable resin composition in advance, in addition to a method of applying a liquid directly onto a substrate. The coating layer formed by coating a thin film of a film of ethylene terephthalate or the like is applied.

The photocurable resin composition of the present invention is suitably used as a permanent film of a printed wiring board, and is suitably used as a solder resist or an interlayer insulating material.

[Examples]

Hereinafter, the present invention will be described in more detail by way of Examples and Comparative Examples. However, the present invention is not limited to the Examples and Comparative Examples. In addition, unless otherwise specified, "parts" means mass parts, and "%" means mass%.

[Reference example] (Measurement of 5% reduction temperature of photopolymerization initiator)

The 5% reduction temperature of Omnipol 910 manufactured by IHT Co., Ltd. was measured using a differential thermal-thermal weight simultaneous measurement device (TG/DTA) to measure the weight loss at a constant rate under the following conditions, and the thermal weight was determined to be 5 The temperature at which % is reduced. The obtained heating loss curve is shown in Fig. 1. The 5% reduction temperature was 318 °C.

Assay sample: photopolymerization initiator (10 mg of this sample was metered on the sample vessel).

Measuring machine: TG/DTA6200 manufactured by Hitachi High-Tech Science Co., Ltd.

Measuring range: 30 ° C ~ 600 ° C.

Heating rate: 10 ° C / min.

(Synthesis or preparation of carboxyl group-containing resins) [A-1: Synthesis of carboxyl group-containing resin]

To 600 g of diethylene glycol monoethyl ether acetate, an o-cresol novolac type epoxy resin (manufactured by DIC Corporation, EPICLON N-695, softening point 95 ° C, epoxy equivalent 214, average functional group number 7.6) 1070 g ( Shrinking sweet The oil base number (total number of aromatic rings): 5.0 mol), 360 g of acrylic acid (5.0 mol), and 1.5 g of hydroquinone were stirred while heating to 100 ° C and dissolved until uniform. Next, 4.3 g of triphenylphosphine was placed in the solution, and after heating to 110 ° C, the reaction was allowed to proceed for 2 hours. Thereafter, the temperature was raised to 120 ° C, and then the reaction was further carried out for 12 hours. 415 g of an aromatic hydrocarbon (Solvesso 150) and 456.0 g (3.0 mol) of tetrahydrophthalic anhydride were placed in the obtained reaction liquid, and the reaction was carried out at 110 ° C for 4 hours, and the solid content was obtained after cooling. A carboxyl group-containing resin solution having an acid value of 89 mgKOH/g and a solid content of 65%. The obtained resin solution is hereinafter referred to as A-1.

[A-2: Modulation of carboxyl group-containing resin]

CYCLOMER P (ACA) Z250 (solid content: 45%, acid value: 70.0 mgKOH/g) manufactured by Daicel Chemical Industry Co., Ltd. was used. This resin solution is referred to as A-2 hereinafter.

[Examples 1 to 3 and Comparative Examples 1 and 2] (Modulation of photocurable resin composition)

Each component described in the following Table 1 was kneaded by a triaxial roll mill to prepare a photocurable resin composition. The unit of the blending amount in the table is part by mass. In addition, the photopolymerization initiator represented by the above general formula (I) is a photopolymerization initiator using the above Chemical Formula No. 1.

The following evaluation of the obtained photocurable composition was carried out. The evaluation results are shown in Table 2 below.

<Photopolymerization initiator properties>

It was confirmed by visual observation that the photopolymerization initiator was liquid or powder at room temperature.

<solder heat resistance>

A rosin-based flux was applied to the test substrate and immersed in a solder bath set at 260 ° C for 30 seconds.

After the test substrate was washed with an organic solvent, the test was performed by a cellophane adhesive tape, and the evaluation was performed based on the following criteria.

○: There is no change at all.

×: The ridge of the hardened coating film was confirmed.

<pencil hardness>

The hardened coating film was tested in accordance with the test method of JIS C 5400, and the highest hardness was observed without damage to the coating film.

<sensitivity>

The photocurable resin compositions of the examples and the comparative examples were completely coated on a full copper substrate by screen printing, and dried at 80 ° C for 20 minutes. Next, the substrate was developed by a stage exposure meter (step tablet/Kodak No. 2), exposed to a metal halide lamp at 400 mJ/cm ² , and then sprayed at a pressure of 0.2 MPa in a 1 wt% Na ₂ CO ₃ aqueous solution. The maximum number of residual gloss is used as the sensitivity.

<逸气>

The photocurable compositions of the examples and the comparative examples were subjected to full-coating by screen printing on a copper foil substrate on which a pattern was formed, and dried at 80 ° C for 20 minutes. Next, the substrate was exposed to light using an exposure apparatus equipped with a metal halide lamp through a photomask, and developed by a 1% by mass Na ₂ CO ₃ aqueous solution having a spray pressure of 0.2 MPa at 30° C. to form a resist pattern. Next, a part of the substrate was subjected to an additional treatment and heated at 150 ° C for 60 minutes to prepare a thermally hardened substrate.

In a heating and off-loading device (TDU) manufactured by GERSTEL, a powder sample was taken from the prepared resist and placed. Thereafter, the outgassing component at a heat extraction temperature of 150 ° C for 10 minutes was collected using liquid nitrogen at -60 ° C. The collected off-gas components were separated and analyzed by a gas chromatography mass spectrometer (6890N/5973N) manufactured by Agilent Technologies, Inc., and quantified by conversion to n-dodecane, and evaluated according to the following criteria.

○: There is almost no fustive component.

△: A slight outgassing component was confirmed.

×: A large amount of outgassing components.

*1: The carboxyl group-containing resin solution A-1 obtained above; o-cresol novolac type epoxy resin (CN) / acrylic acid (AA) / tetrahydrophthalic anhydride (THPAn) (the amount of blending in the table) System represents the solid component)

*2: The carboxyl group-containing resin solution A-2 (CYCLOMER P (ACA) Z250) obtained as described above; copolymerized resin (the blending amount in the table indicates the solid content)

*3: OMNIPOL 910 (manufactured by IHT); polyethylene glycol (200) bis(β-4-[4-(2-dimethylamino-2-benzyl)butanylphenyl]peri Propionate

*4: Irgacure 907 (manufactured by BASF Japan); 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one

*5: Lucirin TPO-L (manufactured by BASF Japan); ethyl-2,4,6-trimethylbenzimidylphenylphosphonate

*6: DPHA (manufactured by Nippon Kayaku Co., Ltd.); dipentaerythritol hexaacrylate

*7: TMPTA (manufactured by Nippon Kayaku Co., Ltd.); Trimethylolpropane triacrylate

*8: B-30 (manufactured by Dai Chemical Industry Co., Ltd.); barium sulfate

*9: KS-66 (manufactured by Shin-Etsu Silicone Co., Ltd.); polydimethyl methoxy oxane

*10: jER828 (made by Mitsubishi Chemical Corporation); bisphenol A type epoxy resin

As is apparent from the results shown in Table 1, the photocurable resin composition of the example containing the photopolymerization initiator represented by the above general formula (I) is excellent in suppressing generation of outgas.

Claims (6)

A photocurable resin composition comprising a carboxyl group-containing resin, a compound having two or more ethylenically unsaturated groups in a molecule, and a photopolymerization initiator represented by the following general formula (I); (wherein R represents a structure represented by the following formula (II), and l ₁ represents an integer of 2 to 4, and m ₁ represents an integer of 1 or more), The photocurable resin composition of claim 1, further comprising a thermosetting component. The photocurable resin composition of claim 2, wherein the thermosetting component is an epoxy resin. The photocurable resin composition of claim 1 which is formed into a resist. A cured product obtained by curing the photocurable resin composition according to any one of claims 1 to 4. A printed wiring board characterized by having a cured product of claim 5.