Photocurable thermosetting resin composition

Abstract

To provide a photocurable thermosetting resin composition which enables formation of a cured film having good adhesion to a mold resin and having good resistance to plating, even if the resin composition is not subjected to plasma treatment.SOLUTION: There is provided a photocurable thermosetting resin composition which includes a carboxy group-containing resin, an inorganic filler, a photopolymerization initiator, a thermosetting resin, and a thermosetting catalyst. In the photocurable thermosetting resin composition, the inorganic filler has an average particle diameter of 1 μm or less, the inorganic filler includes talc, the content thereof is 2 mass% or more and 10 mass% or less with respect to the total resin composition in terms of solid content, the inorganic filler further includes a monofunctional polymerizable compound having a silyloxy group and an ethylenic unsaturated group, and the content of the monofunctional polymerizable compound is 0.05 mass% or more and 2.5 mass% or less with respect to the total resin composition in terms of solid content.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photocurable thermosetting resin composition, a dry film, a cured product, and an electronic component. [Background technology]

[0002] Generally, in printed wiring boards used in electronic devices, when mounting electronic components on the printed wiring board, a solder resist is formed on a substrate on which a circuit pattern is formed. Furthermore, when surface-mounting electronic components such as IC chips on the solder resist, a molding resin may be formed on the solder resist to protect the mounted electronic components. Printed wiring boards manufactured in this manner may peel off if the adhesion between the solder resist and the molding resin is poor.

[0003] To address the above-mentioned problems, the solder resist surface is roughened before sealing with a mold resin. For example, the solder resist surface is modified by plasma treatment (Patent Document 1), or a solder resist is formed using a dry film with fine irregularities formed on the surface of a photosensitive resin layer (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-294285 [Patent Document 2] Japanese Patent Application Publication No. 2017-191335 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the increasing sophistication of electronic devices has created a demand for high-resolution patterns to be formed using solder resist. To achieve this, it is necessary to suppress scattering during pattern formation exposure, which requires, for example, the particle size of the inorganic filler to be sufficiently small. However, if the particle size of the inorganic filler is made small, the inorganic filler tends to fall off when the solder resist is subjected to the above-mentioned plasma treatment, resulting in a brittle and easily damaged surface. Furthermore, as electronic devices become lighter, thinner, and smaller, thinner solder resists are being required. However, thinner solder resists may result in reduced plating resistance, for example, due to the permeation of plating solutions into the solder resist during plating.

[0006] Therefore, one aspect of the present invention aims to provide a photocurable thermosetting resin composition that can form a cured film that has good adhesion to molding resins and good plating resistance without the need for plasma treatment. [Means for solving the problem]

[0007] The present invention includes the following aspects.

[0008] [1] Carboxy group-containing resin, inorganic filler, photopolymerization initiator, thermosetting resins, and thermosetting catalyst, A photocurable thermosetting resin composition comprising: The inorganic filler has an average particle size of 1 μm or less, the inorganic filler contains talc, and the content of talc is 2% by mass or more and 10% by mass or less in terms of solid content relative to the entire resin composition; A photocurable thermosetting resin composition further comprising a monofunctional polymerizable compound having a silyloxy group and an ethylenically unsaturated group, the content of which is 0.05% by mass or more and 2.5% by mass or less in terms of solid content based on the entire resin composition.

[0009] [2] The photocurable thermosetting resin composition according to [1], wherein the thermosetting resin contains an epoxy resin having a nitrile rubber structure.

[0010] [3] The photocurable thermosetting resin composition according to [2], wherein the content of the epoxy resin is 1% by mass or more and 30% by mass or less in terms of solid content relative to the entire resin composition.

[0011] [4] The photocurable thermosetting resin composition according to any one of [1] to [3], wherein the inorganic filler has an average particle size of 0.1 μm or more.

[0012] [5] The photocurable thermosetting resin composition according to any one of [1] to [4], wherein the ratio of the content of the polymerizable compound to the total content of the inorganic filler is 0.001 or more and 0.07 or less in terms of solid content.

[0013] [6] In the infrared absorption spectrum of a dried coating film formed from the resin composition, -1 Peak intensity I1 near 2237cm -1 The photocurable thermosetting resin composition according to any one of [2] to [5], wherein the intensity ratio (I2 / I1) of the peak intensity I2 in the vicinity of the wavelength of the photocurable thermosetting resin composition is 0.1 or more and 0.4 or less.

[0014] [7] A dry film having a resin layer obtained by applying the photocurable thermosetting resin composition according to any one of [1] to [6] to a first film and drying the applied composition.

[0015] [8] A cured product obtained by curing the photocurable thermosetting resin composition according to any one of [1] to [6] or the resin layer of the dry film according to [7].

[0016] [9] An electronic component comprising the cured product according to [8]. [Effects of the Invention]

[0017] According to one aspect of the present invention, it is possible to provide a photocurable thermosetting resin composition that can form a cured film that has good adhesion to a molding resin and good plating resistance. DETAILED DESCRIPTION OF THE INVENTION

[0018] In this specification, when multiple substances corresponding to each component are present in the composition, the content of each component refers to the total amount of those multiple substances present in the composition, unless otherwise specified. Furthermore, the upper and lower limits of the numerical ranges described in this specification can be arbitrarily selected and combined from the numerical values ​​exemplified as numerical ranges. In this specification, "(meth)acrylate" is a general term for acrylate, methacrylate, and mixtures thereof, and the same applies to other similar expressions. Furthermore, "solid content" refers to the residue remaining after removing volatile components (e.g., organic solvents) from a composition or its components. Hereinafter, embodiments of the present invention will be described in detail. However, the following embodiments are intended to embody the technical concept of the present invention, and are intended to exemplify photocurable thermosetting resin compositions, dry films, cured products, and electronic components. However, the present invention is not limited to the photocurable thermosetting resin compositions, dry films, cured products, and electronic components shown below.

[0019] [Photocurable thermosetting resin composition] The photocurable thermosetting resin composition (hereinafter simply referred to as "resin composition") contains a carboxyl group-containing resin, an inorganic filler, a photopolymerization initiator, a thermosetting resin, and a thermosetting catalyst. The inorganic filler contained in the resin composition may have an average particle size of 1 μm or less. The inorganic filler may also contain talc, and the content of talc may be 2% by mass or more and 10% by mass or less, calculated as solid content, based on the total resin composition. The resin composition may further contain a monofunctional polymerizable compound having a silyloxy group and an ethylenically unsaturated group (hereinafter also referred to as "specific polymerizable compound"). The content of the specific polymerizable compound may be 0.05% by mass or more and 2.5% by mass or less, calculated as solid content, based on the total resin composition.

[0020] By setting the average particle size of the inorganic filler contained in the photocurable thermosetting resin composition to 1 μm or less, the average particle size of the inorganic filler becomes sufficiently small relative to the thickness of the cured film, thereby suppressing the occurrence of defects such as holes penetrating the cured film and tending to improve the plating resistance of the cured film. The inclusion of talc as an inorganic filler improves adhesion to the molding resin. This is thought to be due, for example, to the hydrophilic groups contained in the talc improving the wettability of the cured film with the molding resin. The inclusion of a specific polymerizable compound in the photocurable thermosetting resin composition improves adhesion to the molding resin. This is thought to be due, for example, to the specific polymerizable compound having a silyloxy group capable of bonding to the inorganic filler and an ethylenically unsaturated group capable of bonding to the resin component, thereby forming a covalent bond between the inorganic filler in the cured film and the resin component via the specific polymerizable compound, thereby improving the strength of the cured film.

[0021] <Carboxy group-containing resin> The photocurable thermosetting resin composition contains a carboxy group-containing resin. By including the carboxy group-containing resin, the resin composition can be imparted with alkaline developability. From the viewpoint of photocurability and development resistance, the carboxy group-containing resin preferably contains a carboxy group-containing photosensitive resin having an ethylenically unsaturated group in the molecule in addition to a carboxy group. The ethylenically unsaturated group is preferably derived from acrylic acid, methacrylic acid, or a derivative thereof.

[0022] Specific examples of the carboxyl group-containing resin include the following: One type of carboxyl group-containing resin may be used alone, or two or more types may be used in combination.

[0023] (1) A carboxyl group-containing photosensitive resin obtained by reacting a bifunctional or more polyfunctional (solid) epoxy resin with (meth)acrylic acid, and then adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the hydroxyl groups present in the side chain.

[0024] (2) A carboxyl group-containing photosensitive resin in which the hydroxyl groups of a bifunctional (solid) epoxy resin are further epoxidized with epichlorohydrin, and then (meth)acrylic acid is reacted with the resulting polyfunctional epoxy resin, and a dibasic acid anhydride is added to the resulting hydroxyl groups.

[0025] (3) A carboxyl group-containing photosensitive resin obtained by reacting an epoxy compound having two or more epoxy groups per molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group per molecule and an unsaturated group-containing monocarboxylic acid such as (meth)acrylic acid, and then reacting the alcoholic hydroxyl groups of the resulting reaction product with a polybasic acid anhydride such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, or adipic acid.

[0026] (4) A carboxyl group-containing photosensitive resin obtained by reacting a compound having two or more phenolic hydroxyl groups in one molecule, such as bisphenol A, bisphenol F, bisphenol S, novolac-type phenolic resin, poly-p-hydroxystyrene, a condensation product of naphthol and aldehydes, or a condensation product of dihydroxynaphthalene and aldehydes, with an alkylene oxide, such as ethylene oxide or propylene oxide, and then reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, such as (meth)acrylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0027] (5) A carboxyl group-containing photosensitive resin obtained by reacting a compound having two or more phenolic hydroxyl groups per molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate, reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0028] (6) A carboxyl group-containing photosensitive resin obtained by adding a compound having a cyclic ether group and a (meth)acryloyl group in one molecule to a carboxyl group-containing urethane resin obtained by reacting an acid anhydride with the terminal of a urethane resin obtained by polyaddition reaction of a diisocyanate compound such as an aliphatic diisocyanate, a branched aliphatic diisocyanate, an alicyclic diisocyanate, or an aromatic diisocyanate with a diol compound such as a polycarbonate polyol, a polyether polyol, a polyester polyol, a polyolefin polyol, an acrylic polyol, a bisphenol A alkylene oxide adduct diol, or a compound having a phenolic hydroxyl group or an alcoholic hydroxyl group.

[0029] (7) A carboxyl group-containing urethane resin in which a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as a hydroxyalkyl (meth)acrylate, is added during the synthesis of the carboxyl group-containing urethane resin by polyaddition reaction of a diisocyanate with a carboxyl group-containing dialcohol compound such as dimethylolpropionic acid or dimethylolbutyric acid, and a diol compound, resulting in a terminal (meth)acrylated carboxyl group-containing urethane resin.

[0030] (8) A carboxyl group-containing urethane resin obtained by adding a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as an equimolar reactant of isophorone diisocyanate and pentaerythritol triacrylate, during the synthesis of the carboxyl group-containing urethane resin by polyaddition reaction of a diisocyanate, a carboxyl group-containing dialcohol compound, and a diol compound, to form a (meth)acrylic terminal carboxyl group-containing urethane resin.

[0031] (9) A carboxyl group-containing photosensitive resin obtained by copolymerizing an unsaturated carboxylic acid such as (meth)acrylic acid with an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth)acrylate, or isobutylene, to which a compound having a cyclic ether group and a (meth)acryloyl group in one molecule has been added.

[0032] (10) A carboxyl group-containing photosensitive resin obtained by reacting a polyfunctional oxetane resin with a dicarboxylic acid such as adipic acid, phthalic acid, or hexahydrophthalic acid, and then adding a dibasic acid anhydride to the resulting primary hydroxyl group to obtain a carboxyl group-containing polyester resin, to which a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule, such as glycidyl (meth)acrylate or α-methylglycidyl (meth)acrylate, is further added.

[0033] (11) A carboxyl group-containing photosensitive resin obtained by adding a compound having a cyclic ether group and a (meth)acryloyl group in one molecule to any one of the carboxyl group-containing photosensitive resins (1) to (5), (7), (8), and (10) described above.

[0034] Among the above-mentioned carboxyl group-containing photosensitive resins, one or more of the carboxyl group-containing photosensitive resins (1) and (4) to (8) can be particularly preferably used.

[0035] The carboxyl group-containing resins having ethylenically unsaturated groups as described above have many carboxyl groups in the side chains of the backbone polymer, so they can be developed with an alkaline aqueous solution.

[0036] The acid value of the carboxyl group-containing resin may be, for example, 30 mgKOH / g or more and 200 mgKOH / g or less, preferably 40 mgKOH / g or more and 150 mgKOH / g or less, and more preferably 45 mgKOH / g or more and 120 mgKOH / g or less. When the acid value of the carboxyl group-containing resin is equal to or greater than the lower limit (e.g., 30 mgKOH / g or more), alkaline developability is improved. Furthermore, when the acid value of the carboxyl group-containing resin is equal to or less than the upper limit (e.g., 200 mgKOH / g or less), dissolution of the exposed portion in the developer can be suppressed, thereby preventing unnecessary line thinning and, in some cases, dissolution and peeling of the exposed and unexposed portions in the developer without distinction, thereby enabling good patterned resist writing.

[0037] The weight-average molecular weight Mw of the carboxyl group-containing resin varies depending on the resin skeleton, but may be, for example, 2,000 to 150,000, preferably 2,500 to 100,000, or 3,000 to 50,000. When the weight-average molecular weight is above the lower limit, the tack-free performance is good, the moisture resistance of the coating film after exposure is good, and film loss during development tends to be suppressed, thereby suppressing a decrease in resolution. When the weight-average molecular weight is below the upper limit, the developability and storage stability tend to be good. In this specification, the weight-average molecular weight refers to the value measured by gel permeation chromatography (GPC) (polystyrene equivalent).

[0038] The content of the carboxyl group-containing resin, calculated as solid content, of the entire photocurable thermosetting resin composition may be, for example, 20% by mass to 60% by mass, preferably 22% by mass to 50% by mass, more preferably 23% by mass to 40% by mass, and even more preferably 25% by mass to 35% by mass. When the content of the carboxyl group-containing resin is within the above range, better alkaline developability can be imparted.

[0039] <Inorganic filler> The photocurable thermosetting resin composition contains an inorganic filler, and the inorganic filler may have an average particle size of 1 μm or less.

[0040] The average particle size of the inorganic filler may be, for example, 0.1 μm or more and 1 μm or less, preferably 0.2 μm or more and 0.9 μm or less, and more preferably 0.3 μm or more and 0.8 μm or less. When the average particle size of the inorganic filler is below the above upper limit (e.g., 1 μm or less), plating resistance, particularly gold plating resistance, can be imparted to the cured film of the resin composition. This is thought to be because, by making the average particle size of the inorganic filler sufficiently small relative to the thickness of the cured film, the occurrence of defects such as holes penetrating the cured film can be suppressed. When the average particle size of the inorganic filler is above the above lower limit (e.g., 0.1 μm or more), an increase in the viscosity of the resin composition can be suppressed, which may prevent poor debubbling or poor lamination of the dry film.

[0041] The average particle size of the inorganic filler is a value measured and calculated as follows in a scanning electron microscope (SEM) image. First, obtain an SEM image under the following conditions: Measurement equipment: JEOL Ltd. JSM-7600 Acceleration voltage: 5.0 kV Measurement mode: COMPO image (backscattered electron composition image) Observation magnification: 5000x The obtained image is then binarized using Otsu's method with image analysis software (ImageJ). The particle area S of the particles is determined from the binarized image using image analysis software (ImageJ). The particle area S of the obtained particles is assumed to be a circle, and the particle size l is calculated using the following formula 1. The median value obtained from the particle size l of 100 randomly selected particles is taken as the average particle size D50.

number

[0042] The shape of the inorganic filler is not particularly limited, and may be, for example, spherical, scaly, needle-like, etc. In one embodiment, a scaly shape may be preferable from the viewpoint of further improving adhesion to the molding resin.

[0043] Examples of inorganic fillers include talc, silica, crystalline silica, barium sulfate, Neuburg silica, aluminum hydroxide, glass powder, clay, magnesium carbonate, calcium carbonate, natural mica, synthetic mica, aluminum hydroxide, barium titanate, iron oxide, non-fibrous glass, hydrotalcite, mineral wool, aluminum silicate, calcium silicate, zinc oxide, and alumina. The inorganic filler may contain at least one selected from the group consisting of these. One type of inorganic filler may be used alone, or two or more types may be used in combination. Among these, talc, silica, and barium sulfate are preferred from the viewpoints of resolution and low thermal expansion.

[0044] The inorganic filler may be surface-treated or not. When a part or all of the inorganic fillers contained in the resin composition are surface-treated inorganic fillers, the viscosity increase of the resin composition is suppressed, and the stability of the resin composition over time tends to be further improved. The surface treatment agent is not particularly limited, but examples thereof include silane coupling agents such as vinylsilane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, and mercaptosilane coupling agents, organosilazane compounds, titanate coupling agents, aluminate coupling agents, and zirconium coupling agents.

[0045] Examples of vinylsilane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, (meth)acryloxypropylmethyldimethoxysilane, (meth)acryloxysilane, (meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, and 3-(meth)acryloxypropyltriethoxysilane. Examples of aminosilane coupling agents include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, ureidopropyltriethoxysilane, N-phenylaminopropyltrimethoxysilane, and N-2-(aminoethyl)aminopropyltrimethoxysilane. Examples of epoxysilane coupling agents include glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, glycidoxypropylmethyldiethoxysilane, glycidylbutyltrimethoxysilane, and (3,4-epoxycyclohexyl)ethyltrimethoxysilane. Examples of mercaptosilane coupling agents include mercatopropyltrimethoxysilane and mercatopropyltriethoxysilane. Silane coupling agents such as methyltrimethoxysilane, octadecyltrimethoxysilane, phenyltrimethoxysilane, imidazolesilane, and triazinesilane can also be used. Examples of organosilazane compounds include hexamethyldisilazane, hexaphenyldisilazane, trisilazane, cyclotrisilazane, and 1,1,3,3,5,5-hexamethylcyclotrisilazane.Titanate coupling agents include butyl titanate dimer, titanium octylene glycolate, diisopropoxytitanium bis(triethanolamine), dihydroxytitanium bislactate, dihydroxybis(ammonium lactate)titanium, bis(dioctyl pyrophosphate)ethylene titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, tri-n-butoxytitanium monostearate, tetra-n-butyl titanate, tetra(2-ethylhexyl) titanate, tetraisopropyl bis(dioctyl phosphite)titanate, and tetraoctyl bis(ditridecyl phosphite)titanate. Examples of suitable coupling agents include tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, isopropyl trioctanoyl titanate, isopropyl tricumylphenyl titanate, isopropyl triisostearoyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl dimethacrylisostearoyl titanate, isopropyl tri(dioctylphosphate) titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tris(dioctylpyrophosphate) titanate, and isopropyl tris(N-amidoethylaminoethyl) titanate. Examples of suitable coupling agents include acetoalkoxyaluminum diisopropylate, aluminum diisopropoxymonoethylacetoacetate, aluminum trisethylacetoacetate, and aluminum trisacetylacetonate. Examples of zirconium coupling agents include zirconium acetate, ammonium zirconium carbonate, and zirconium fluoride.

[0046] The total content of the inorganic filler in the resin composition may be, in terms of solid content, preferably 10% by mass or more and 90% by mass or less, more preferably 15% by mass or more and 60% by mass or less, and even more preferably 20% by mass or more and 40% by mass or less, based on the entire resin composition.

[0047] The inorganic filler preferably contains at least talc. By including talc in the inorganic filler, the adhesive strength of the cured film to the molding resin can be improved. This is thought to be because the inclusion of talc having a hydrophilic group in the resin composition improves the wettability of the cured film with the molding resin.

[0048] The average particle size of the talc may be, for example, 0.1 μm or more and 1 μm or less, preferably 0.2 μm or more and 0.9 μm or less, and more preferably 0.5 μm or more and 0.8 μm or less. When the average particle size of the talc is equal to or less than the upper limit (for example, 1 μm or less), plating resistance can be imparted to the cured film of the resin composition. When the average particle size of the talc is equal to or more than the lower limit (for example, 0.1 μm or more), an increase in the viscosity of the resin composition can be suppressed, which may prevent poor debubbling or poor lamination of the dry film. The average particle size of the talc can be measured using the same method as that for measuring the average particle size of the inorganic filler.

[0049] The shape of the talc may be, for example, a hexagonal plate, a scale, a fine powder, etc. In one embodiment, a scale shape may be preferable from the viewpoint of further improving adhesion to the molding resin.

[0050] The talc may be surface-treated or not. When the talc is a surface-treated inorganic filler in part or in whole, the viscosity increase of the resin composition is suppressed, and the stability of the resin composition over time tends to be further improved. The surface treatment agent is not particularly limited, and examples thereof include the same surface treatment agents as those for the inorganic filler.

[0051] When talc is contained, the inorganic filler may contain other inorganic fillers other than talc. Examples of other inorganic fillers include silica, crystalline silica, barium sulfate, Neuburg silica, aluminum hydroxide, glass powder, clay, magnesium carbonate, calcium carbonate, natural mica, synthetic mica, aluminum hydroxide, barium titanate, iron oxide, non-fibrous glass, hydrotalcite, mineral wool, aluminum silicate, calcium silicate, zinc oxide, and alumina. The other inorganic fillers may be used alone or in combination of two or more. Among these, silica and barium sulfate are preferred from the viewpoints of resolution and low thermal expansion.

[0052] The talc content in the resin composition may be, for example, 2% by mass to 10% by mass, preferably 2.5% by mass to 9% by mass, and more preferably 3% by mass to 8% by mass, calculated as solid content, relative to the entire resin composition. When the talc content is within the above range, adhesion to the molding resin tends to be improved. When the talc content is equal to or greater than the above lower limit, the talc's effect of improving the wettability of the cured film can improve adhesion to the molding resin. When the talc content is equal to or less than the above upper limit, a decrease in cured film strength can be suppressed, and adhesion to the molding resin can be improved.

[0053] The content of talc in the resin composition may be, in terms of solid content, preferably 2% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 40% by mass or less, and even more preferably 10% by mass or more and 35% by mass or less, relative to the total content of the carboxy group-containing resin.

[0054] The talc content in the inorganic filler, calculated as solid content, may be preferably 5% by mass or more and 40% by mass or less, more preferably 7.5% by mass or more and 35% by mass or less, even more preferably 10% by mass or more and 30% by mass or less, and particularly preferably 15% by mass or more and 25% by mass or less, relative to the total content of the inorganic filler.

[0055] <Specific polymerizable compound> The photocurable thermosetting resin composition may contain a monofunctional specific polymerizable compound having a silyloxy group and an ethylenically unsaturated group. The silyloxy group of the specific polymerizable compound forms a covalent bond with the inorganic filler, and the ethylenically unsaturated group forms a covalent bond with resin components such as a carboxyl group-containing resin and a thermosetting resin. That is, by including the specific polymerizable compound in the resin composition, a covalent bond is formed between the inorganic filler in the cured film and the resin component via the specific polymerizable compound. Therefore, when the resin composition contains the specific polymerizable compound, the strength of the cured film is improved and the adhesion to the mold resin can be enhanced.

[0056] The silyloxy group is a group containing an O-Si bond and may be, for example, a silanol group, an alkoxysilyl group, or a combination thereof. The silyloxy group may be any of a dialkylhydroxysilyl group, an alkyldihydroxysilyl group, a trihydroxysilyl group, a dialkylmonoalkoxysilyl group, an alkyldialkoxysilyl group, a trialkoxysilyl group, a dialkoxyhydroxysilyl group, and an alkoxydihydrosilyl group. Two or more silyloxy groups may be condensed to form one silyloxy group. The alkyl group and the alkoxy group in the silyloxy group may have, for example, 1 to 3 carbon atoms. The specific polymerizable compound may have only one silyloxy group, or two or more silyloxy groups.

[0057] Examples of the ethylenically unsaturated group include a vinyl group and a (meth)acrylic group.

[0058] The specific polymerizable compound may have a group other than a silyloxy group and an ethylenically unsaturated group, and may have, for example, an amino group, an epoxy group, or the like in addition to a silyloxy group and an ethylenically unsaturated group.

[0059] Specific examples of the specific polymerizable compound include compounds having a silanol group and a vinyl group, such as 3-ethenyl-1,1,3,3-tetrahydroxy-1-disiloxaneamine, 1,3-distyryl-1,1,3,3-disiloxanetetrol, and 1,3-diethenyl-1,1,3,3-disiloxanetetrol; and compounds having a silyloxy group and a (meth)acrylic group, such as 3-methacryloxypropyltrihydroxysilane, 3-methacryloxypropyldihydroxymethoxysilane, and 3-methacryloxypropylhydroxydimethoxysilane. Commercially available compounds include X-12-1353 manufactured by Shin-Etsu Chemical Co., Ltd.

[0060] The content of the specific polymerizable compound in the resin composition may be, for example, 0.05 to 2.5 mass% of the total resin composition, calculated as solid content, preferably 0.05 to 1.5 mass%, more preferably 0.07 to 0.7 mass%. When the content of the specific polymerizable compound is within the above range, the strength of the cured film is improved, and the adhesion to the molding resin can be enhanced.

[0061] The content of the specific polymerizable compound in the resin composition may be, in terms of solid content, preferably 0.1% by mass or more and 8% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less, and even more preferably 0.3% by mass or more and 5% by mass or less, relative to the total content of the carboxy group-containing resin.

[0062] In the resin composition, the ratio of the content of the specific polymerizable compound to the total content of the inorganic fillers (content of the specific polymerizable compound / total content of the inorganic fillers), converted into solid content, may be preferably 0.0010 or more and 0.0700 or less, more preferably 0.0015 or more and 0.0500 or less, and even more preferably 0.0030 or more and 0.0500 or less.

[0063] <Thermosetting resin> The photocurable thermosetting resin composition may contain a thermosetting resin, which can improve the heat resistance and electrical insulation properties of the resin composition.

[0064] Examples of thermosetting resins include epoxy resins, oxetane resins, melamine resins, and silicone resins. These may be used alone or in combination of two or more. Among these, from the viewpoint of low-temperature curing properties, the thermosetting resin may preferably contain at least one selected from the group consisting of epoxy resins and oxetane resins, and more preferably contain at least an epoxy resin.

[0065] Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol S type epoxy resins, bisphenol F type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, and alicyclic epoxy resins.

[0066] Specific examples of epoxy resins include jER828, jER834, jER1001, and jER1004 manufactured by Mitsubishi Chemical Corporation; Epicron 840, Epicron 850, Epicron 1050, and Epicron 2055 manufactured by DIC Corporation; Epotohto YD-011, YD-013, YD-127, and YD-128 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; and DER317, DER331, and DE manufactured by Dow Chemical Japan. Bisphenol A epoxy resins such as R661, DER664, Sumi-Epoxy ESA-011, ESA-014, ELA-115, ELA-128 manufactured by Sumitomo Chemical Co., Ltd., AER330, AER331, AER661, AER664 manufactured by Asahi Kasei E-Materials Corporation; jERYL903 manufactured by Mitsubishi Chemical Corporation, Epicron 152, Epicron 165 manufactured by DIC Corporation, Epicron 166 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. Brominated epoxy resins such as Pototo YDB-400 and YDB-500, DER542 manufactured by Dow Chemical Japan, Sumi-Epoxy ESB-400 and ESB-700 manufactured by Sumitomo Chemical Co., Ltd., and AER711 and AER714 manufactured by Asahi Kasei E-Materials Corporation; jER152 and jER154 manufactured by Mitsubishi Chemical Corporation, DEN431 and DEN438 manufactured by Dow Chemical Japan, and Epicron N-7 manufactured by DIC Corporation. 30, Epicron N-770, Epicron N-865, Epotohto YDCN-701, YDCN-704 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306, NC-3000 manufactured by Nippon Kayaku Co., Ltd., Sumi-Epoxy ESCN-195X, ESCN-220 manufactured by Sumitomo Chemical Co., Ltd., and AER manufactured by Asahi Kasei E-Materials Corporation.Novolac epoxy resins such as ECN-235, ECN-299, YDCN-700-2, YDCN-700-3, YDCN-700-5, YDCN-700-7, YDCN-700-10, YDCN-704, and YDCN-704A manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., and Epiclon N-680, N-690, and N-695 (all trade names) manufactured by DIC Corporation; Epiclon 830 manufactured by DIC Corporation, jER807 manufactured by Mitsubishi Chemical Corporation, and Epotohto YDF-170, YDF-175, and YDF-2004 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. Bisphenol F epoxy resins; hydrogenated bisphenol A epoxy resins such as Epotohto ST-2004, ST-2007, and ST-3000 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; jER604 manufactured by Mitsubishi Chemical Co., Ltd., Epotohto YH-434 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; glycidyl amine epoxy resins such as Sumi-Epoxy ELM-120 manufactured by Sumitomo Chemical Co., Ltd.; hydantoin epoxy resins; alicyclic epoxy resins such as Celloxide 2021 manufactured by Daicel Corporation; YL-933 manufactured by Mitsubishi Chemical Co., Ltd., and TEN manufactured by Dow Chemical Japan.trihydroxyphenylmethane type epoxy resins such as EPPN-501 and EPPN-502; bixylenol type or biphenol type epoxy resins or mixtures thereof such as YL-6056, YX-4000 and YL-6121 manufactured by Mitsubishi Chemical Corporation; bisphenol S type epoxy resins such as EBPS-200 manufactured by Nippon Kayaku Co., Ltd., EPX-30 manufactured by ADEKA Corporation and EXA-1514 manufactured by DIC Corporation; bisphenol A novolac type epoxy resins such as jER157S manufactured by Mitsubishi Chemical Corporation; tetraphenylolethane type epoxy resins such as jERYL-931 manufactured by Mitsubishi Chemical Corporation; heterocyclic epoxy resins such as TEPIC manufactured by Nissan Chemical Industries, Ltd.; diglycidyl phthalate resins such as Blenmer DGT manufactured by NOF Corporation; Examples of epoxy resins include, but are not limited to, tetraglycidylxylenoylethane resins such as ZX-1063 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; naphthalene group-containing epoxy resins such as ESN-190 and ESN-360 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. and HP-4032, EXA-4750, and EXA-4700 manufactured by DIC Corporation; dicyclopentadiene skeleton epoxy resins such as HP-7200 and HP-7200H manufactured by DIC Corporation; glycidyl methacrylate copolymer epoxy resins such as CP-50S and CP-50M manufactured by NOF Corporation; cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resins; and CTBN-modified epoxy resins (e.g., YR-102 and YR-450 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.). Among these, bisphenol A epoxy resins, heterocyclic epoxy resins, and mixtures thereof are preferred due to their excellent discoloration resistance. These epoxy resins may be used alone or in combination of two or more.

[0067] The epoxy equivalent of the epoxy resin may be, for example, 80 g / eq or more and 1000 g / eq or less, preferably 90 g / eq or more and 500 g / eq or less, and more preferably 100 g / eq or more and 400 g / eq or less.

[0068] In one embodiment, the thermosetting resin preferably contains an epoxy resin having a nitrile rubber structure (hereinafter also referred to as "NBR-containing epoxy resin"). When the thermosetting resin contains an NBR-containing epoxy resin, the adhesion to the molding resin can be further improved. Although the reason for this is not clear, it is thought that the NBR-containing epoxy resin improves the wettability of the coating film with the molding resin and improves the coating film strength.

[0069] From the viewpoint of dryness to the touch, the viscosity of the NBR-containing epoxy resin at 50°C may be preferably 20,000 mPa·s or more and 100,000 mPa·s or less, more preferably 40,000 mPa·s or more and 80,000 mPa·s or less, and even more preferably 50,000 mPa·s or more and 70,000 mPa·s or less. The viscosity of the NBR-containing epoxy resin can be determined, for example, from the 30-second value measured at 50°C and a rotor rotation speed of 5.0 rpm using a TVE-33H (manufactured by Toki Sangyo Co., Ltd., rotor 3°×R9.7).

[0070] An example of an NBR-containing epoxy resin is EPR-4030 manufactured by ADEKA Corporation.

[0071] The content of the NBR-containing epoxy resin in the resin composition, calculated as solid content, may be preferably 1% by mass or more and 40% by mass or less, more preferably 3% by mass or more and 30% by mass or less, and even more preferably 5% by mass or more and 25% by mass or less, based on the total resin composition. When the content of the NBR-containing epoxy resin is equal to or more than the lower limit, adhesion to the molding resin tends to be further improved. When the content of the NBR-containing epoxy resin is equal to or less than the upper limit, the stability over time of the resin composition tends to be improved.

[0072] When the thermosetting resin contains an NBR-containing epoxy resin, it is preferable that the thermosetting resin contains, in addition to the NBR-containing epoxy resin, a thermosetting resin that does not have a nitrile rubber structure, such as an epoxy resin that does not have a nitrile rubber structure, from the viewpoint of the temporal stability of the cured product. Examples of the thermosetting resin that does not have a nitrile rubber structure include the thermosetting resins such as the epoxy resins exemplified above. The content of the NBR-containing epoxy resin in the thermosetting resin may be, in terms of solid content, preferably 5% by mass or more and 80% by mass or less, more preferably 10% by mass or more and 70% by mass or less, and even more preferably 20% by mass or more and 65% by mass or less, relative to the total content of the thermosetting resin.

[0073] <Photopolymerization initiator> The photocurable thermosetting resin composition may contain a photopolymerization initiator. As the photopolymerization initiator, a photopolymerization initiator known as a photopolymerization initiator or a photoradical generator can be used.

[0074] Examples of the photopolymerization initiator include bisacylphosphine oxides, monoacylphosphine oxides, hydroxyacetophenones, benzoins, benzoin alkyl ethers, benzophenones, acetophenones, thioxanthones, anthraquinones, ketals, benzoic acid esters, oxime esters, titanocenes, phenyl disulfide 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, and tetramethylthiuram disulfide.

[0075] Examples of bisacylphosphine oxides include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (IRGACURE819 manufactured by BASF Japan Ltd.). Examples of monoacylphosphine oxides include 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid isopropyl ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (IRGACURE TPO manufactured by BASF Japan Ltd.), etc. Examples of hydroxyacetophenones include 1-hydroxycyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, etc. Examples of benzoins include benzoin, benzil, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether, etc. Examples of benzophenones include benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone, etc.Examples of acetophenones include acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone, N,N-dimethylaminoacetophenone, and 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one. Examples of thioxanthones include thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone. Examples of anthraquinones include anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone. Examples of ketals include acetophenone dimethyl ketal and benzyl dimethyl ketal. Examples of benzoic acid esters include ethyl 4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, and p-dimethylbenzoic acid ethyl ester. Examples of oxime esters include 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime), etc. Examples of titanocenes include bis(η 5Examples of the photopolymerization initiator include bis(cyclopentadienyl)-bis(2,6-difluoro-3-(2-(1H-pyrrol-1-yl)ethyl)phenyl)titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1H-pyrrol-1-yl)ethyl)phenyl]titanium, etc. The photopolymerization initiator may be used alone or in combination of two or more.

[0076] The content of the photopolymerization initiator may be, for example, 0.1% by mass or more and 30% by mass or less, preferably 1% by mass or more and 10% by mass or less, and more preferably 2% by mass or more and 8% by mass or less, in terms of solid content relative to the resin composition.

[0077] <Thermosetting catalyst> The photocurable thermosetting resin composition may contain a thermosetting catalyst.

[0078] Examples of the thermal curing catalyst include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, and 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; phosphorus compounds such as triphenylphosphine; and S-triazine derivatives such as guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine-isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine-isocyanuric acid adduct. Commercially available examples include 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, and 2P4MHZ (all trade names of imidazole-based compounds) manufactured by Shikoku Chemical Industry Co., Ltd., and U-CAT (registered trademark) 3503N and U-CAT3502T (all trade names of dimethylamine-blocked isocyanate compounds), DBU, DBN, U-CATSA102, and U-CAT5002 (all bicyclic amidine compounds and salts thereof) manufactured by San-Apro Co., Ltd. The heat curing catalysts may be used alone or in combination of two or more.

[0079] The content of the thermosetting catalyst may be, for example, 0.1% by mass or more and 10% by mass or less, preferably 0.5% by mass or more and 8% by mass or less, and more preferably 1% by mass or more and 5% by mass or less, in terms of solid content relative to the thermosetting resin.

[0080] <Photopolymerizable monomer> The photocurable thermosetting resin composition may further contain a photopolymerizable monomer, if necessary.

[0081] Examples of photopolymerizable monomers include (meth)acrylate monomers, allyl compounds, etc. Examples of (meth)acrylate monomers include (meth)acrylamides, (meth)acrylic acid esters, hydroxyalkyl (meth)acrylates, alkoxyalkylene glycol mono(meth)acrylates, alkylene polyol poly(meth)acrylates, polyoxyalkylene glycol poly(meth)acrylates, isocyanurate-type poly(meth)acrylates, and hydroxypivalic acid neopentyl glycol ester di(meth)acrylate.

[0082] Examples of (meth)acrylamides include (meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-ethoxymethyl(meth)acrylamide, and N-butoxymethyl(meth)acrylamide. Examples of (meth)acrylic acid esters include 2-ethylhexyl(meth)acrylate, lauryl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, isobornyl(meth)acrylate, phenyl(meth)acrylate, and phenoxyethyl(meth)acrylate. Examples of hydroxyalkyl(meth)acrylates include hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, and pentaerythritol tri(meth)acrylate. Examples of alkoxyalkylene glycol mono(meth)acrylates include methoxyethyl(meth)acrylate and ethoxyethyl(meth)acrylate. Examples of ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, and alkylene polyol poly(meth)acrylates include neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. Examples of polyoxyalkylene glycol poly(meth)acrylates include diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, ethoxylated trimethylolpropane triacrylate, and propoxylated trimethylolpropane tri(meth)acrylate. Examples of isocyanurate-type poly(meth)acrylates include tris[(meth)acryloxyethyl]isocyanurate. Examples of the allyl compound include triallyl isocyanurate, diallyl phthalate, diallyl isophthalate, etc. The photopolymerizable monomers may be used alone or in combination of two or more.

[0083] The content of the photopolymerizable monomer may be, for example, 1% by mass or more and 30% by mass or less, preferably 2% by mass or more and 25% by mass or less, and more preferably 2.5% by mass or more and 20% by mass or less, in terms of solid content relative to the resin composition.

[0084] <Coloring agent> The photocurable thermosetting resin composition may contain a colorant. As the colorant, a commonly used and known colorant such as red, blue, green, yellow, white, or black can be used, and any of a pigment, dye, and coloring matter can be used.

[0085] Specifically, the following colors may be given the Color Index (CI; published by The Society of Dyers and Colorists) numbers:

[0086] Red colorants include monoazo, disazodisazo, azolake, benzimidazolone, perylene, diketopyrrolopyrrole, condensed azo, anthraquinone, and quinacridone. Blue colorants include phthalocyanine and anthraquinone, and pigment compounds classified as pigments can be used. In addition to these, metal-substituted or unsubstituted phthalocyanine compounds can also be used. Green colorants include phthalocyanine, anthraquinone, and perylene. In addition to these, metal-substituted or unsubstituted phthalocyanine compounds can also be used. Yellow colorants include monoazo, disazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone. White colorants include rutile or anatase titanium dioxide. Examples of black colorants include carbon black, graphite, iron oxide, titanium black, iron oxide, anthraquinone, cobalt oxide, copper oxide, manganese, antimony oxide, nickel oxide, perylene, aniline, molybdenum sulfide, bismuth sulfide, etc. In addition, purple, orange, brown, and other colorants may be added to adjust the color tone.

[0087] The content of the colorant in the resin composition is preferably 0.1% by mass to 10% by mass, more preferably 0.2% by mass to 5% by mass, calculated as solid content. When the content of the colorant in the resin composition is within this range, the circuit hiding ability and the resolution tend to be improved.

[0088] <Organic solvents> The photocurable thermosetting resin composition may contain an organic solvent for the purposes of preparing the resin composition and adjusting the viscosity when applying it to a substrate film.

[0089] Examples of organic solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, and tripropylene glycol monomethyl ether; esters such as ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha. These organic solvents may be used alone or in combination.

[0090] <Other additives> The photocurable thermosetting resin composition may contain other additives known and commonly used in the field of electronic materials, such as thermal polymerization inhibitors, ultraviolet absorbers, silane coupling agents, plasticizers, flame retardants, antistatic agents, antioxidants, antibacterial and antifungal agents, antifoaming agents, leveling agents, thickeners, adhesion-imparting agents, thixotropy-imparting agents, photoinitiator assistants, sensitizers, thermoplastic resins, organic fillers, release agents, surface treatment agents, dispersants, dispersion assistants, surface modifiers, stabilizers, and phosphors.

[0091] The total content of other additives may be, for example, 0.01% by mass or more and 5% by mass or less, preferably 0.05% by mass or more and 3% by mass or less, and more preferably 0.1% by mass or more and 2% by mass or less, in terms of solid content, relative to the entire resin composition.

[0092] <Photocurable thermosetting resin composition> The photocurable thermosetting resin composition according to one embodiment of the present invention can form a cured film that has high adhesion to a molding resin and plating resistance, particularly gold plating resistance, even without plasma treatment, and the cured film can be suitably used as a solder resist.

[0093] The solid content of the photocurable thermosetting resin composition may be preferably 40% by mass or more and 80% by mass or less, and more preferably 50% by mass or more and 70% by mass or less, based on the total mass of the resin composition.

[0094] The photocurable thermosetting resin composition has a wavelength of 2237 cm in the infrared absorption spectrum of a dried coating film formed from the resin composition. -1 Near and 3677 cm -1 It is preferable to have a peak around 2237 cm -1 The peak in the vicinity corresponds to the peak derived from, for example, a cyano group. -1 The peak around 3677 cm is an indicator that the resin composition contains an NBR-containing epoxy resin containing a cyano group. -1 The peak in the vicinity corresponds to, for example, a peak derived from talc. Therefore, in the infrared absorption spectrum of the dried coating film, the peak at 2237 cm-1 Near and 3677 cm -1 When the resin composition has a peak in the vicinity of 100° C., it is suggested that the resin composition contains an NBR-containing epoxy resin and talc. The peak here means the maximum absorption peak.

[0095] In the infrared absorption spectrum of the dried coating film formed from the resin composition, -1 Peak intensity I1 for peaks near 2237 cm -1 The intensity ratio (I2 / I1) of the peak intensity I2 at the peak in the vicinity of I2 may be preferably 0.1 or more and 0.40 or less, more preferably 0.15 or more and 0.38 or less, and even more preferably 0.20 or more and 0.35 or less. When the intensity ratio is 0.1 or more, adhesion to the mold tends to be improved, and when it is 0.40 or less, stability over time tends to be improved.

[0096] The dried coating film used for measuring the infrared absorption spectrum is formed by applying the resin composition to a uniform thickness on a substrate such as a copper-plated substrate and drying it for 25 to 35 minutes at a temperature of 78 to 82° C. The infrared absorption spectrum of the dried coating film can be measured using a Fourier transform infrared spectrometer such as a PerkinElmer Spectrum 100, for example, by the method described in the Examples.

[0097] The photocurable thermosetting resin composition may be used in the form of a dry film or in a liquid form. When used in a liquid form, it may be one-component or two or more-component.

[0098] The photocurable thermosetting resin composition can be produced by a known method, for example, by blending the components to be contained in the resin composition and stirring and kneading them with a mixer, kneader, or the like.

[0099] [Dry film] The photocurable thermosetting resin composition can also be in the form of a dry film comprising a first film (e.g., a support (carrier) film) and a resin layer formed on the first film as a dry coating of the photocurable thermosetting resin composition. That is, the present invention may include a dry film as one embodiment. The dry film comprises a first film and a resin layer.

[0100] When forming a dry film, the photocurable thermosetting resin composition is diluted with an organic solvent to adjust the viscosity to an appropriate level, and then coated to a uniform thickness on the first film using a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, or the like. The dried coating film is typically dried at a temperature of 50°C to 130°C for 1 minute to 30 minutes to obtain a dry coating film. There are no particular restrictions on the coating film thickness (resin layer thickness), but the thickness after drying may be, for example, 1 μm to 50 μm, and preferably may be selected appropriately from the range of 3 μm to 15 μm.

[0101] The first film can be any known film without particular limitation, and examples of suitable films include polyester films such as polyethylene terephthalate and polyethylene naphthalate, and films made of thermoplastic resins such as polyimide films, polyamideimide films, polypropylene films, and polystyrene films. Among these, polyester films are preferred from the viewpoints of heat resistance, mechanical strength, ease of handling, etc. A laminate of these films can also be used as the first film.

[0102] From the viewpoint of improving mechanical strength, the above-mentioned thermoplastic resin film is preferably a film stretched in a uniaxial or biaxial direction.

[0103] The thickness of the first film is not particularly limited, but may be, for example, 10 μm or more and 150 μm or less.

[0104] After forming a resin layer consisting of a dry coating film of a photocurable thermosetting resin composition on a first film, it is preferable to further laminate a peelable second film (e.g., a protective (cover) film) on the surface of the resin layer for the purpose of preventing dust from adhering to the surface of the resin layer. That is, in one embodiment, the dry film comprises a first film, a resin layer, and a second film, in this order. Examples of the peelable second film that can be used include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper, and any film can be used as long as the adhesive strength between the resin layer and the second film is smaller than the adhesive strength between the resin layer and the first film when the second film is peeled off.

[0105] The thickness of the second protective film is not particularly limited, but may be, for example, 10 μm or more and 150 μm or less.

[0106] To prepare a cured film usable as a solder resist on a printed wiring board using a dry film, the second film is peeled off from the dry film, and the exposed resin layer of the dry film is placed on a substrate with a circuit formed thereon, and the two are bonded together using a laminator or the like to form a resin layer on the substrate with a circuit formed thereon. The formed resin layer is then exposed to light, developed, and heat-cured to form a cured film. The first film can be peeled off either before or after exposure.

[0107] One embodiment of the present invention may include a cured product obtained by curing the photocurable thermosetting resin composition or the resin layer of the dry film.

[0108] One aspect of the present invention may include an electronic component having a cured product. Here, the electronic component refers to a component used in an electronic circuit, such as a printed wiring board. The cured product of the photocurable thermosetting resin composition is suitable as a solder resist for these components.

[0109] A printed wiring board having a cured product of the photocurable thermosetting resin composition as a solder resist has high adhesion to a molding resin and plating resistance, particularly gold plating resistance. [Example]

[0110] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" and "%" are by mass.

[0111] [Synthesis of carboxyl group-containing resin] <Synthesis example 1:*1> 220 parts of cresol novolac epoxy resin (DIC Corporation, EPICLON N-695, epoxy equivalent: 220) was placed in a four-neck flask equipped with a stirrer and reflux condenser, and 214 parts of carbitol acetate was added and dissolved by heating. Next, 0.1 parts of hydroquinone as a polymerization inhibitor and 2.0 parts of dimethylbenzylamine as a reaction catalyst were added. This mixture was heated to 95-105°C, and 72 parts of acrylic acid were slowly added dropwise, allowing the reaction to proceed for 16 hours. The reaction product was cooled to 80-90°C, and 106 parts of tetrahydrophthalic anhydride was added. The reaction was allowed to proceed for 8 hours, cooled, and then discharged. The photosensitive resin thus obtained, which had both ethylenically unsaturated bonds and carboxyl groups, had a nonvolatile content (solid content) of 65%, an acid value of the solid content of 100 mgKOH / g, and a weight-average molecular weight (Mw) of approximately 3,500. This resin will be referred to as A-1 below.

[0112] <Synthesis example 2: A-2> A flask equipped with a condenser and a stirrer was charged with 456 parts of bisphenol A, 228 parts of water, and 649 parts of 37% formalin. While maintaining the temperature below 40°C, 228 parts of 25% aqueous sodium hydroxide was added. The reaction was continued for 10 hours at 50°C. After the reaction was completed, the mixture was cooled to 40°C and neutralized to pH 4 with 37.5% aqueous phosphoric acid while maintaining the temperature below 40°C. The mixture was then allowed to stand and the aqueous layer was separated. After separation, 300 parts of methyl isobutyl ketone was added and uniformly dissolved. The mixture was then washed three times with 500 parts of distilled water. Water and solvent were removed under reduced pressure at a temperature below 50°C. The resulting polymethylol compound was dissolved in 550 parts of methanol to obtain 1230 parts of a methanol solution of the polymethylol compound. A portion of the resulting methanol solution of the polymethylol compound was dried at room temperature in a vacuum dryer, revealing a solids content of 55.2%. 500 parts of the resulting methanol solution of the polymethylol compound and 440 parts of 2,6-xylenol were charged and dissolved uniformly at 50°C. After the solution was dissolved uniformly, the methanol was removed under reduced pressure at a temperature of 50°C or less. 8 parts of oxalic acid was then added, and the reaction was carried out at 100°C for 10 hours. After the reaction was completed, the distillate was removed under reduced pressure at 180°C and 50 mmHg, yielding 550 parts of novolak resin A. Furthermore, 130 parts of the novolak resin A, 2.6 parts of a 50% aqueous sodium hydroxide solution, and 100 parts of toluene / methyl isobutyl ketone (mass ratio = 2 / 1) were charged into an autoclave equipped with a thermometer, a nitrogen inlet / alkylene oxide inlet, and a stirrer, and the system was purged with nitrogen while stirring. Then, the temperature was raised to 150°C and 8 kg / cm 2 45 parts of ethylene oxide was gradually introduced and the reaction was carried out at a gauge pressure of 0.0 kg / cm. 2 The reaction was continued for about 4 hours until the reaction mixture reached a final concentration, after which it was cooled to room temperature. 3.3 parts of a 36% aqueous solution of hydrochloric acid was added to the reaction solution and mixed to neutralize the sodium hydroxide. The neutralized reaction product was diluted with toluene, washed with water three times, and the solvent was removed using an evaporator to obtain an ethylene oxide adduct of novolak resin A with a hydroxyl value of 175 g / eq. This product had an average of 1 mole of ethylene oxide added per equivalent of phenolic hydroxyl group. 175 parts of the ethylene oxide adduct of novolak resin A, 50 parts of acrylic acid, 3.0 parts of p-toluenesulfonic acid, 0.1 parts of hydroquinone monomethyl ether, and 130 parts of toluene were charged into a reactor equipped with a stirrer, thermometer, and air inlet tube, and the mixture was stirred while blowing in air. The temperature was raised to 115°C, and the reaction was continued for another 4 hours while distilling off the water produced by the reaction as an azeotrope with toluene. The reaction solution was washed with 5% aqueous NaCl solution, and the toluene was removed by distillation under reduced pressure. Diethylene glycol monoethyl ether acetate was then added to obtain an acrylate resin solution with a solids content of 68%. Next, 312 parts of the obtained acrylate resin solution, 0.1 parts of hydroquinone monomethyl ether, and 0.3 parts of triphenylphosphine were placed in a four-neck flask equipped with a stirrer and a reflux condenser, and the mixture was heated to 110°C. 45 parts of tetrahydrophthalic anhydride was added, and the mixture was allowed to react for 4 hours. After cooling, a solution of a carboxyl group-containing resin was obtained with a solid content of 70%, a solid acid value of 65 mgKOH / g, and a weight-average molecular weight Mw of approximately 12,000. Hereinafter, this resin solution is referred to as A-2.

[0113] [Preparation of silica slurry] <Preparation Example 1> 400 g of spherical silica (SFP-30M manufactured by Denka Co., Ltd.), 590 g of PMA (propylene glycol monomethyl ether acetate) as a dispersion medium, and 10 g of 3-glycidoxypropyltrimethoxysilane (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.) were uniformly dispersed in a bead mill for 2 hours to obtain a silica slurry (solid content 41%, silica content 40%). Measurements showed that the average particle size D50 of the obtained silica slurry was 0.6 μm.

[0114] [Preparation of barium sulfate slurry] <Preparation Example 2> 700 g of barium sulfate (B-30 (alumina surface-treated barium sulfate) manufactured by Sakai Chemical Industry Co., Ltd.), 250 g of PMA (propylene glycol monomethyl ether acetate) as a solvent, and 50 g of dispersant (BYK BYK-111 manufactured by BYK) were uniformly dispersed in a bead mill for 2 hours to obtain a barium sulfate slurry (solid content 75%, barium sulfate content 70%). As a result of measurement, the average particle size D50 of the obtained barium sulfate slurry was 0.30 μm.

[0115] [Preparation of surface-treated talc] <Preparation Example 3> 97 g of talc (Nano Ace D-600 manufactured by Nippon Talc Co., Ltd.) was uniformly dispersed in 3 g of a surface treatment agent, KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd., to perform surface treatment on the talc, thereby obtaining surface-treated talc (solid content 100%, talc content 97%). Measurements showed that the average particle size D50 of the obtained surface-treated talc was 0.6 μm.

[0116] [Examples 1 to 14 and Comparative Examples 1 to 3] According to the formulation shown in Table 1, each component was blended in the indicated proportions (parts by mass), premixed in a mixer, and then kneaded in a three-roll mill to prepare a resin composition. The values ​​in Table 1 are blend amounts in parts by mass in a solution containing solids and solvent. Note that "-" in Table 1 indicates that no component was added.

[0117] [Table 1]

[0118] Details of each component in the table are as follows:

[0119] Carboxy group-containing resin *1: Carboxy group-containing resin A-1 obtained in Synthesis Example 1 above, solid content 68% *2: Carboxy group-containing resin A-2 obtained in Synthesis Example 2 above, solid content 70%

[0120] inorganic filler *3: Silica slurry obtained in Preparation Example 1 above (D50 = 0.6 μm, solid content 41%, silica content 40%) *4: Barium sulfate slurry obtained in Preparation Example 2 above (D50 = 0.30 μm, solid content 75, barium sulfate content 70%) *5: Surface-treated nanotalc obtained in Preparation Example 3 above (D50 = 0.6 μm, solid content 100%, talc content 97%) *6: Nanotalc (Nano Ace D-600): Made by Nippon Talc Co., Ltd., talc, D50 = 0.6 μm, solid content 100% *7: Talc (K-1): Made by Nippon Talc Co., Ltd., D50 = 8 μm, solid content 100%

[0121] Photopolymerization initiator *8: Omnirad 379EG: IGM Resins BV, 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one, solid, molecular weight 380.5, solid content 100%

[0122] thermosetting resin *9: Bisphenol A epoxy resin (N-870-75EA): manufactured by DIC Corporation, epoxy equivalent 205 (g / eq), solid content 75% *10: Epoxy resin with nitrile rubber structure (EPR-4030): ADEKA Corporation, NBR-modified epoxy resin, epoxy equivalent 365 (g / eq), viscosity 60,000 mPa·s (50℃), solid content 100%

[0123] thermosetting catalyst *11: Melamine, manufactured by Nikka Trading Co., Ltd., 100% solids

[0124] Specific polymerizable compound *12: X-12-1353 (having silanol groups): manufactured by Shin-Etsu Chemical Co., Ltd., 3-ethenyl-1,1,3,3,-tetrahydroxy-1-disiloxaneamine, solid content 20%

[0125] Photopolymerizable Monomer *13: A-9550: Shin-Nakamura Chemical Co., Ltd., dipentaerythritol polyacrylate, viscosity 6500 mPa·s (25°C), solid content 100%

[0126] sensitizer *14: KAYACURE DETX-S: Manufactured by Nippon Kayaku Co., Ltd., 2,4-diethylthioxanthone, molecular weight 268.37, solid content 100%

[0127] coloring agent *15: Blue coloring pigment (Firstgen Blue 5380), manufactured by DIC, 100% solids *16: Yellow coloring pigment (Yellow S1515), manufactured by BASF, 100% solids

[0128] additives *17: Defoamer (KS-66): Shin-Etsu Chemical Co., Ltd., oil compound type, 100% solids

[0129] solvent *18: Jukisol CA, manufactured by Shinko Organic Chemical Industry Co., Ltd., diethylene glycol monoethyl ether acetate, molecular weight 176.21, solid content 0%

[0130] [measurement] 1. Average particle size D50 of inorganic filler The average particle size D50 of each inorganic filler was measured and calculated under the following conditions using a scanning electron microscope (SEM: JSM-7600 manufactured by JEOL Ltd.). First, scanning electron microscope (SEM) images were obtained under the following conditions. Accelerating voltage: 5.0 kV Measurement mode: COMPO image (backscattered electron composition image) Observation magnification: 5000x The obtained image was then binarized using Otsu's method with image analysis software (ImageJ). The particle area S of the particles was determined using the binarized image using image analysis software (ImageJ). The particle area S of the obtained particles was assumed to be a circle, and the particle size l was calculated using the following formula 1. The median value obtained from the particle size l of 100 randomly selected particles was taken as the average particle size D50.

number

[0131] 2. Infrared absorption spectrum measurement using the ATR method (attenuated total reflection measurement) of Fourier transform infrared spectroscopy (FT-IR) The resin compositions obtained in the examples and comparative examples were applied to a copper-plated substrate (size 15 cm × 9.5 cm, thickness 0.8 mm) by screen printing to form a 10 μm-thick dry coating film, and then dried in a heat circulation drying oven at 80 ° C for 30 minutes to obtain a dry coating film. IR absorption spectra of each of the obtained dry coating films were obtained by the ATR method (prism: diamond, window plate: KRS-5) using an FT-IR (Fourier transform infrared spectroscopy) analyzer (PerkinElmer, Spectrum 100). From the infrared absorption spectrum obtained above, 3677 cm -1 Peak intensities at I1 and 2237 cm -1 The peak intensity I2 at this point was determined, and the peak intensity ratio I2 / I1 was calculated.

[0132] [evaluation] The resin compositions obtained in the examples and comparative examples were evaluated as follows. The evaluation results are shown in Table 1.

[0133] 1. Stability over time For the resin compositions obtained in the examples and comparative examples, 2 ml of the resin composition was taken immediately after kneading in a three-roll mill, and the viscosity was measured using a cone-plate viscometer (manufactured by Toki Sangyo Co., Ltd., TV-30 model, rotor 3° × R9.7) at 25°C, a rotation speed of 5 rpm (shear rate 10 s ー1The viscosity of the resin compositions obtained in the Examples and Comparative Examples was measured at 30 seconds after storage. The resin compositions obtained in the Examples and Comparative Examples were stored for two weeks in a dark place at 15 to 25°C, and the viscosity was measured after two weeks in the same manner as above. The viscosity change rate of each resin composition after two weeks was calculated from the measured viscosity and evaluated according to the following evaluation criteria.

[0134] Evaluation criteria A: Viscosity change rate after 2 weeks is 15% or less B: Viscosity change rate after 2 weeks is more than 15% and less than 30% C: Viscosity change rate after 2 weeks is 30% or more

[0135] 2. Adhesion to molding resin The resin compositions obtained in the examples and comparative examples were applied to copper-plated substrates (15 cm x 9.5 cm, 0.8 mm thick, pre-treated with chemical polishing using CZ8101 manufactured by MEC Co., Ltd.) by screen printing to a thickness of 10 μm after curing. The resulting resin composition was then dried at 80 °C for 30 minutes in a thermal circulation drying oven (DF610 manufactured by Yamato Scientific Co., Ltd.). The resulting dried coating was subjected to full-surface exposure using an Oak Seisakusho HMW680GW (metal halide lamp, scattered light) at an exposure dose equivalent to 10 steps of a 41-step step tablet. The resulting coating was then developed for 60 seconds in a 1.0 wt% sodium carbonate aqueous solution at 30 °C, 0.2 MPa, and further developed with UV light at an integrated exposure dose of 1000 mJ. The resin layer was then cured by heating at 160 °C for 1 hour, resulting in the formation of a cured coating on the copper-plated substrate. A substrate for evaluation was then prepared. Then, an EMC pin (diameter 2.5 mm, height 3.0 mm, cup shape) was pressed onto the formed hardened coating using a manual mold press (Apic Yamada, MZ-667) with a contact area of ​​5 mm. 2 Next, the shear strength of the EMC pin was measured at 500 μm / s and room temperature using a bond tester (4000Plus / Optima Nordson). The measured shear strength was evaluated according to the following criteria.

[0136] Evaluation criteria A: Shear strength is 150N or more B: Shear strength is 120N or more but less than 150N C: Shear strength less than 120N

[0137] 3. Plating resistance Similar to the evaluation substrate prepared in "2. Adhesion to Mold Resin," an evaluation substrate was prepared by forming a cured coating on a copper-plated substrate. The evaluation substrate was immersed in an acidic degreasing solution (20 vol% aqueous solution of Metex L-5B, manufactured by Japan MacDermid Co., Ltd.) at 30°C for 3 minutes, then rinsed with water. It was then immersed in a 14.3 wt% aqueous solution of ammonium persulfate at room temperature for 3 minutes for soft etching, and then immersed in running water for 3 minutes for rinsing. The evaluation substrate was then immersed in a 10 vol% aqueous solution of sulfuric acid at room temperature for 1 minute, then rinsed with running water. The evaluation substrate was then immersed in a catalyst solution (10 vol% aqueous solution of Metal Plate Activator 350, manufactured by Meltex Co., Ltd.) at 30°C for 3 minutes to apply a catalyst, then immersed in running water for 3 minutes for rinsing. The evaluation substrate thus catalyst-applied was immersed in a nickel plating solution (20 vol% aqueous solution of Melplate Ni-865M, manufactured by Meltex) at 85°C for 20 minutes to perform electroless nickel plating, and then immersed in a 10 vol% aqueous sulfuric acid solution at room temperature for 1 minute, followed by immersion in running water for 1 minute to rinse. Next, the specimen was immersed in an 85°C gold plating solution (manufactured by Meltex, an aqueous solution of Melplate AU-6601MA 10 vol%, Melplate AU-6601MB 10 vol%, and gold potassium cyanide 3 wt%) for 30 minutes to perform electroless gold plating, and then rinsed in 60°C warm water for 3 minutes. Finally, the substrate was washed with water and dried to obtain a substrate for evaluating plating resistance that had been electrolessly gold plated. The cured coating film on the substrate for evaluating plating resistance was observed for defects. The plating resistance was evaluated according to the following evaluation criteria.

[0138] Evaluation criteria A: There were no defects that penetrated from the cured coating to the substrate (base). B: There was a defect that penetrated from the cured coating film to the substrate (base).

Claims

1. carboxyl group-containing resin, inorganic filler, photopolymerization initiator, thermosetting resins, and thermosetting catalyst, A photocurable thermosetting resin composition comprising: The inorganic filler has an average particle size of 1 μm or less, the inorganic filler contains talc, and the content of talc is 2% by mass or more and 10% by mass or less in terms of solid content with respect to the entire resin composition; a photocurable thermosetting resin composition, further comprising a monofunctional polymerizable compound having a silyloxy group and an ethylenically unsaturated group, the content of which is 0.05% by mass or more and 2.5% by mass or less in terms of solid content based on the entire resin composition;

2. The photocurable thermosetting resin composition according to claim 1 , wherein the thermosetting resin comprises an epoxy resin having a nitrile rubber structure.

3. The photocurable thermosetting resin composition according to claim 2 , wherein the content of the epoxy resin is 1% by mass or more and 30% by mass or less in terms of solid content relative to the entire resin composition.

4. 2. The photocurable thermosetting resin composition according to claim 1, wherein the inorganic filler has an average particle size of 0.1 μm or more.

5. 2. The photocurable thermosetting resin composition according to claim 1, wherein a ratio of a content of the polymerizable compound to a total content of the inorganic filler is 0.001 or more and 0.07 or less in terms of solid content.

6. In the infrared absorption spectrum of a dried coating film formed from the resin composition, －１ Peak intensity I near １ 2237 cm －１ Peak intensity I near ２ Intensity ratio (I ２ / I １ 3. The photocurable thermosetting resin composition according to claim 2, wherein the value of (a) is 0.1 or more and 0.4 or less.

7. A dry film having a resin layer obtained by applying the photocurable thermosetting resin composition according to claim 1 to a first film and drying the applied resin layer.

8. A cured product obtained by curing the photocurable thermosetting resin composition according to any one of claims 1 to 6 or the resin layer of the dry film according to claim 7.

9. An electronic component comprising the cured product according to claim 8.

Images