JP7053345B2 - Curable resin composition, dry film, cured product and printed wiring board - Google Patents

Description

The present invention relates to a curable resin composition suitable for forming a film such as a solder resist of a printed wiring board, a dry film and a cured product thereof, and more particularly, to have a fluidity suitable for coating on a printed wiring board or the like. The present invention relates to a curable resin composition, a dry film and a cured product thereof, which have a reduced dielectric constant and dielectric tangent. The present invention also relates to a printed wiring board in which a permanent film such as a solder resist is formed by a cured product of such a composition.

Generally, in a printed wiring board, from the viewpoint of heat resistance and electrical insulation, a modified epoxy acrylate compound, an epoxy resin, or the like is used as a main component for an interlayer insulating material or a solder resist material, and an additive component such as a filler is further contained. Resin compositions are widely used.

On the other hand, in the information and communication field, with the diversification of information and the increase in the amount of information, the frequency of radio waves used for wireless information communication is increasing, and even in the case of printed wiring board materials, transmission loss in information transmission during communication is progressing. There is a demand for the development of materials that can handle high frequencies with reduced noise. That is, since this transmission loss is generally expressed as the product of the dielectric constant and the dielectric loss tangent of the cured product of the resin composition constituting the interlayer insulating material or the solder resist, both the dielectric constant and the dielectric loss tangent are reduced. It was necessary to develop a material to make it.

On the other hand, conventionally, as a method of reducing both the dielectric constant and the dielectric loss tangent of the printed wiring board material, a method of blending a large amount of a filler having a small dielectric constant and a dielectric loss tangent into the resin composition constituting the interlayer insulating material or the solder resist has been used. Proposed.

For example, Patent Document 1 proposes a resin composition containing a specific amount of a fluororesin filler.

Japanese Unexamined Patent Publication No. 2016-166347

However, if a large amount of filler having a small dielectric constant or dielectric loss tangent is added to the modified epoxy acrylate compound or epoxy resin contained in the interlayer insulating material or solder resist, the transmission loss of the material is reduced, while the filler and other components are contained. It was found that the difference in polarity (electrical bias of the molecular structure) causes new problems such as increased thixotropy of the composition, markedly reduced fluidity, and eventually the coating work by screen printing or the like becomes impossible. rice field.

Therefore, an object of the present invention is to provide a curable resin composition capable of reducing both the dielectric constant and the dielectric loss tangent of a cured product while maintaining excellent fluidity and coatability.

The present inventors have diligently studied toward the realization of the above object. As a result, in addition to the fact that the resin component is a curing system of the carboxyl group-containing resin and the isocyanate compound, the fluidity and coatability of the material are deteriorated by using the fluororesin filler and silica together as the filler component. It has been found that both the dielectric constant and the dielectric loss tangent of the cured product can be reduced without any problem, and the present invention has been completed.

That is, the curable resin composition of the present invention is characterized by containing (A) a carboxyl group-containing resin, (B) an isocyanate compound, (C) a fluororesin filler, (D) silica, and (E) an organic solvent. do.
The dry film of the present invention is characterized by having a resin layer obtained from the curable resin composition.
The cured product of the present invention is characterized by being obtained by curing the curable resin composition or the resin layer of the dry film.
The printed wiring board of the present invention is characterized by having the cured product.

According to the present invention, it is possible to provide a curable resin composition in which both the dielectric constant and the dielectric loss tangent of the cured product are reduced while maintaining excellent fluidity and coatability.

Hereinafter, the curable resin composition of the present invention will be specifically described, but the present invention is not limited thereto.

When isomers are present in the described compounds, all possible isomers can be used in the present invention unless otherwise specified.

The curable resin composition of the present invention contains at least (A) a carboxyl group-containing resin, (B) an isocyanate compound, (C) a fluororesin filler, (D) silica, and (E) an organic solvent.
Further, the curable resin composition of the present invention may further contain (F) a photopolymerization initiator and (G) a photopolymerizable monomer as preferable components.
Furthermore, the curable resin composition of the present invention may contain other components as long as the effects of the present invention are not impaired.

Hereinafter, each component of the curable resin composition of the present invention will be described.

[(A) Carboxyl group-containing resin]
As the carboxyl group-containing resin, known ones can be used. Further, the carboxyl group-containing resin may be used alone or in combination of two or more.

As the carboxyl group-containing resin, various conventionally known carboxyl group-containing resins having a carboxyl group in the molecule can be used, and a carboxyl group-containing resin having an ethylenically unsaturated double bond in the molecule (carboxyl group-containing photosensitive resin) can be used. (Resin) is preferable. The ethylenically unsaturated double bond is preferably derived from acrylic acid, methacrylic acid, or a derivative thereof. When only a carboxyl group-containing resin having no ethylenically unsaturated double bond in the molecule is used, in order to make the composition photocurable, a compound having a plurality of carbon-carbon unsaturated bonds in the molecule described later will be used. That is, it is necessary to use a photopolymerizable monomer in combination.

Specific examples of the carboxyl group-containing resin include the following compounds (either oligomer or polymer).

(I) A carboxyl group-containing 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, and isobutylene.

(II) Diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates and aromatic diisocyanates, carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, polycarbonate-based polyols and polyether-based compounds. A carboxyl group-containing urethane resin obtained by a double addition reaction of a diol compound such as a polyol, a polyester-based polyol, a polyolefin-based polyol, an acrylic polyol, a bisphenol A-based alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

(III) Diisocyanate and bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin ( Meta) A carboxyl group-containing photosensitive urethane resin obtained by a double addition reaction of an acrylate or a modified partial acid anhydride thereof, a carboxyl group-containing dialcohol compound and a diol compound.

(IV) During the synthesis of the resin of (II) or (III), a compound having one hydroxyl group and one or more (meth) acryloyl groups in a molecule such as hydroxyalkyl (meth) acrylate is added to the terminal (IV). Meta) Acryloylated carboxyl group-containing photosensitive urethane resin.

(V) During the synthesis of the resin of (II) or (III), one isocyanate group and one or more (meth) acryloyl groups are formed in the molecule, such as an isophorone diisocyanate and a pentaerythritol triacrylate homomolar reaction product. Carboxyl group-containing photosensitive urethane resin that is terminal (meth) acrylicized by adding the compound to be possessed.

(VI) A carboxyl group-containing photosensitive resin obtained by reacting a bifunctional or higher polyfunctional (solid) epoxy resin with (meth) acrylic acid and adding a dibasic acid anhydride to a hydroxyl group existing in a side chain.

(VII) Carboxyl obtained by reacting (meth) acrylic acid with a polyfunctional epoxy resin obtained by further epoxidizing the hydroxyl group of a bifunctional (solid) epoxy resin with epichlorohydrin, and adding dibasic acid anhydride to the generated hydroxyl group. Group-containing photosensitive resin.

(VIII) A dicarboxylic acid such as adipic acid, phthalic acid, or hexahydrophthalic acid is reacted with a bifunctional oxetane resin, and the resulting primary hydroxyl group is subjected to two bases such as phthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride. Carboxyl group-containing polyester resin to which acid anhydride is added.

(IX) An epoxy compound having a plurality of epoxy groups in one molecule, a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule such as p-hydroxyphenethyl alcohol, and (meth). Reacting with an unsaturated group-containing monocarboxylic acid such as acrylic acid, maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, adipine with respect to the alcoholic hydroxyl group of the obtained reaction product. A carboxyl group-containing resin obtained by reacting a polybasic acid anhydride such as an acid.

(X) A reaction product obtained by reacting a reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide with an unsaturated group-containing monocarboxylic acid. A carboxyl group-containing photosensitive resin obtained by reacting a substance with a polybasic acid anhydride.

(XI) Obtained by reacting an unsaturated group-containing monocarboxylic acid with a reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate. A carboxyl group-containing photosensitive resin obtained by reacting a reaction product with a polybasic acid anhydride.

(XII) A carboxyl group-containing photosensitive resin obtained by further adding a compound having one epoxy group and one or more (meth) acryloyl groups in one molecule to the resins (I) to (XI).

The acid value of the carboxyl group-containing resin is preferably in the range of 30 to 150 mgKOH / g, and more preferably in the range of 50 to 120 mgKOH / g. When the acid value of the carboxyl group-containing resin is 30 mgKOH / g or more, the heat resistance and strength of the film of the cured product are improved, and when the pattern is formed by photolithography, the developability is good. If it is 150 mgKOH / g or less, the polar groups are reduced, resulting in low dielectric properties. When pattern formation is performed by photolithography, sufficient resistance to the developer of the exposed part is sufficiently obtained, and a normal resist pattern is ensured. It is preferable because it can be drawn in.

The weight average molecular weight of the carboxyl group-containing resin varies depending on the resin skeleton, but is generally preferably in the range of 2,000 to 150,000, more preferably 5,000 to 100,000. When the weight average molecular weight is 2,000 or more, the flexibility and adhesion of the film after curing are good, and when pattern formation by photolithography is performed, the developability is good. When the weight average molecular weight is 150,000 or less, the heat resistance, the insulating property, and the storage stability of the composition after curing are improved. The weight average molecular weight can be measured by gel permeation chromatography.

The carboxyl group-containing resin is not limited to those listed above, and can be used. Among them, the carboxyl group-containing resin synthesized by using a phenol compound such as the carboxyl group-containing resin (X) and (XI) as a starting material has HAST resistance (super accelerated life test) and PCT resistance (saturated vapor pressurization test). ) Is excellent, so it can be preferably used.

The blending amount of the (A) carboxyl group-containing resin is not particularly limited, but may be 10 to 95% by mass, preferably 10 to 80% by mass or the like, per curable resin composition in terms of non-volatile components.

[(B) Isocyanate compound]
As the isocyanate compound, known ones can be used. Further, the isocyanate compound may be used alone or in combination of two or more.

As the isocyanate compound, a polyisocyanate compound can be blended. Examples of the polyisocyanate compound include 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, o-xylylene diisocyanate, m-xylylene diisocyanate and Aromatic polyisocyanates such as 2,4-tolylene dimer; aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4-methylenebis (cyclohexyl isocyanate) and isophorone diisocyanate; bicyclo Alicyclic polyisocyanates such as heptanetriisocyanate; and adducts, burettes, and isocyanurates of the isocyanate compounds mentioned above can be mentioned.

Further, in the present invention, the blocked isocyanate compound is preferable as the isocyanate compound from the viewpoint that the workability is improved due to the excellent storage stability.

As the blocked isocyanate compound, an addition reaction product of the isocyanate compound and the isocyanate blocking agent can be used. Examples of the isocyanate compound that can react with the isocyanate blocking agent include the above-mentioned polyisocyanate compound and the like. Examples of the isocyanate blocking agent include phenolic blocking agents such as phenol, cresol, xylenol, chlorophenol and ethylphenol; lactam blocking agents such as ε-caprolactam, δ-palerolactam, γ-butyrolactam and β-propiolactam; Active oxime-based blocking agents such as ethyl acetoacetate and acetylacetone; methanol, ethanol, propanol, butanol, amyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether, benzyl. Alcohol-based blocking agents such as ether, methyl glycolate, butyl glycolate, diacetone alcohol, methyl lactate and ethyl lactate; oxime-based blocking agents such as formaldehyde xim, acetoaldoxime, acetoxime, methylethylketoxim, diacetylmonooxime and cyclohexaneoxime. Mercaptan-based blocking agents such as butyl mercaptan, hexyl mercaptan, t-butyl mercaptan, thiophenol, methylthiophenol, ethylthiophenol; acid amide-based blocking agents such as acetate amide and benzamide; imides such as succinic acid imide and maleate imide. Oxime-based blocking agents; Amin-based blocking agents such as xylidine, aniline, butylamine, dibutylamine; Imidazole-based blocking agents such as imidazole and 2-ethylimidazole; Imine-based blocking agents such as methyleneimine and propyleneimine; Blocking agent; Examples thereof include maleic acid ester-based blocking agents such as diethyl maleic acid.

Commercially available blocked isocyanate compounds include, for example, Sumijour® BL-3175, BL-4165, BL-1100, BL-1265, Death Module® TPLS-2957, TPLS-2062, TPLS. -2078, TPLS-2117, Desmotherm 2170, Desmotherm 2265 (all manufactured by Sumitomo Bayer Urethane Co., Ltd.), Coronate (registered trademark) 2512, Coronate 2513, Coronate 2520 (all manufactured by Nippon Polyurethane Industry Co., Ltd.), B- 830, B-815, B-846, B-870, B-874, B-882 (all manufactured by Mitsui Takeda Chemical Co., Ltd.), Duranate SBN-70D, TPA-B80E, 17B-60PX, E402-B80T (all All of them can be mentioned as Asahi Kasei Chemicals Co., Ltd., TRIXENE BI 7982, 7950, 7951, 7960, 7961, (Baxenden Chemicals Limited), among which, Duranate SBN-70D and TRIXENE BI 7982. preferable. Sumijour BL-3175 and BL-4265 are obtained by using methylethyloxime as a blocking agent.

The blending amount of the isocyanate compound is 0.01 to 20 parts by mass, preferably 5 to 15 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin in terms of non-volatile components. When the blending amount is within the range of the number of parts by mass, a good permanent coating for circuit protection of the printed wiring board can be obtained by the curing reaction with the carboxyl group-containing resin.

[(C) Fluororesin filler]
As the fluororesin filler, known ones can be used. Further, the fluororesin filler may be used alone or in combination of two or more.

Examples of the fluororesin include polytetrafluoroethylene (PTFE), tetrafluoroethylene / ethylene copolymer (ETFE), tetrafluoroethylene / perfluoroalkyl vinyl ether-based copolymer (PFA), and tetrafluoroethylene / hexafluoropropylene-based polymer. Examples thereof include a copolymer (FEP), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF) and the like.

The shape of the primary particles of the fluororesin filler is not particularly limited, and examples thereof include amorphous, spherical or substantially granular, and among them, spherical and substantially granular are preferable.

The average particle size of the fluororesin filler is preferably 0.1 μm to 50 μm, and more preferably 0.2 μm to 20 μm.

The content of the fluororesin filler is preferably 5% by mass or more and less than 50% by mass, and more preferably 8% by mass or more and 35% by mass or less per curable resin composition in terms of non-volatile components.

As the above-mentioned fluororesin filler, the PTFE filler is particularly preferable. The PTFE filler is not particularly limited, and examples thereof include suspension polymerization type and emulsion polymerization type, and an emulsion polymerization type PTFE filler having excellent dispersibility is more preferable.

Here, in the present specification, the average particle size is an average particle size (D50) including not only the particle size of the primary particles but also the particle size of the secondary particles (aggregates), and is measured by a laser diffraction method. It is the value of D50. Examples of the measuring device by the laser diffraction method include the Microtrac MT3300EXII manufactured by Nikkiso Co., Ltd. The maximum particle diameter (D100) and the particle diameter (D10) can also be measured in the same manner by the above-mentioned apparatus.

[(D) Silica]
The silica may be any known silica that can be used as a filler for electronic materials. In addition, one type of silica may be used alone, or two or more types may be used in combination.

Examples of silica include fused silica, spherical silica, amorphous silica, crystalline silica, fine powder silica and the like, and among them, spherical silica is preferable from the viewpoint of fluidity of the composition.

The shape of the spherical silica may be spherical, and is not limited to that of a true spherical silica. Suitable spherical silica includes, for example, those having a sphericity of 0.8 or more measured as described below, but are not limited thereto.

The sphericity is measured as follows. That is, first, a photograph of spherical silica is taken with a scanning electron microscope (SEM), and from the area and peripheral length of the particles observed on the photograph, (sphericity) = {4π × (area) ÷ (periphery). Long) Calculate as the value calculated in ² }. Specifically, an average value measured for 100 particles can be adopted by using an image processing device.

The average particle size of silica obtained from the volume average particle size distribution measurement result measured by the above-mentioned laser diffraction type particle size distribution measuring device is preferably 0.1 μm to 50 μm, and more preferably the average particle size. It is 0.2 μm to 20 μm.

The content of silica is preferably 5% by mass or more and less than 50% by mass, and more preferably 8% by mass or more and 40% by mass or less per curable resin composition in terms of non-volatile components.

As the silica, either silica that has not been surface-treated or silica that has been surface-treated can be used, and it is particularly preferable to use silica that has been surface-treated from the viewpoint of the fluidity of the composition. In the surface treatment of such silica, either silica in a pre-surface-treated state is blended, or silica of an unsurface-treated product and a surface-treating agent are separately blended to surface-treat the silica in the composition. May be good. The surface treatment agent is not particularly limited, and a known one may be used, but it is preferable to use a surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group as an organic group.

As the coupling agent, a silane-based, titanate-based, aluminate-based, zircoaluminate-based, or other coupling agent can be used. Of these, a silane-based coupling agent is preferable. Examples of such silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N- (2-aminomethyl) -3-aminopropylmethyldimethoxysilane, and N- (2-aminoethyl) -3-amino. Propyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxy) Cyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and the like can be mentioned, which can be used alone or in combination. The treatment amount of these silane-based coupling agents is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of silica. In the present invention, the reactive functional group derived from the coupling agent applied to silica is not included in the compound having a photocurable reactive group and a thermosetting functional group.

The content of such silica is preferably 5% by mass or more and less than 50% by mass, and more preferably 8% by mass or more and 40% by mass or less per curable resin composition in terms of non-volatile components.

As for the amount of the fluororesin filler and silica to be blended, the blending ratio of the fluororesin filler and silica is preferably in the range of 2: 8 to 7: 3, and more preferably 3: 7 to 6: 4. .. Within the range of the content ratio and the compounding ratio, the fluidity of the composition is improved, and the effect of reducing the dielectric constant and the dielectric loss tangent can be obtained.

[(E) Organic solvent]
As the organic solvent, a known one can be used, and it is used for the purpose of preparing a composition, adjusting the viscosity when applied on a printed wiring board, and the like. Therefore, the content of the organic solvent can be appropriately changed according to the purpose. Further, the organic solvent may be used alone or in combination of two or more. Among them, it is preferable to use at least one organic solvent having a dissolution parameter of less than 9. When the organic solvent having a solubility parameter of less than 9 is contained in the curable resin composition, the dispersibility of the low-polarity fluororesin filler and the fluidity of the composition of the present invention are improved. In this specification, the dissolution parameter is calculated based on the Fedors method.

Examples of the organic solvent having a dissolution parameter of less than 9 include n-hexane, cyclohexane, ethylcyclohexane, methylcyclohexane, diethyl ether, isopropyl ether, n-pentane, butyl acetate, xylene, toluene, ethylbenzene, dipropylene glycol dimethyl ether, and dipropylene glycol. Propylene glycol methyl-n-propyl ether, isopropyl acetate, dipropylene glycol methyl ether acetate, ethyl acetate, n-propyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, 3-methoxybutyl acetate, methyl acetate, ethylene glycol mono Examples thereof include butyl ether acetate, diethylene glycol monobutyl ether acetate, and petroleum naphtha (Ipsol 100, Ipsol 150 manufactured by Idemitsu Kosan Co., Ltd.).

Examples of the organic solvent having a dissolution parameter of 9 or more include tetrahydrofuran, ethyl acetate, trichloroethylene, methyl ethyl ketone, acetone, 2-ethylhexanol, ethanol, methanol, 1-propanol, benzyl alcohol, ethylene glycol monomethyl ether acetate, and diethylene glycol mono. Ethyl ether acetate, cyclohexanol acetate, tripropylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol methyl ether, 1,3-butylene glycol diacetate, 1,6-hexanediol diacetate, dipropylene Glycol n-propyl ether, propylene glycol diacetate, 1,4-butanediol diacetate, propylene glycol n-butyl ether, dipropylene glycol methyl ether, propylene glycol n-propyl ether, triacetin, propylene glycol monomethyl ether, 3- Examples thereof include methoxybutanol, diethylene glycol monoethyl ether, n-propyl alcohol, 1,3-butylene glycol and the like.

[(F) Photopolymerization Initiator]
As the photopolymerization initiator, known ones can be used. Further, the photopolymerization initiator may be used alone or in combination of two or more.

Examples of the photopolymerization initiator include bis- (2,6-dichlorobenzoyl) phenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphinoxide, and bis- (2,). 6-Dichlorobenzoyl) -4-propylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -1-naphthylphosphinoxide, bis- (2,6-dimethoxybenzoyl) phenylphosphin oxide, bis- (2,6-dimethoxybenzoyl) 2,6-Dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,5-dimethylphenylphosphinoxide, bis- (2,4,6- Bisacylphosphine oxides such as trimethylbenzoyl) -phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine Monoacylphosphine oxides such as acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid isopropyl ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide; phenyl (2,4) 6-trimethylbenzoyl) ethyl phosphinate, 1-hydroxy-cyclohexylphenylketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one, 2- Hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propane-1-one, 2-hydroxy-2-methyl-1-phenylpropane- Hydroxyacetophenones such as 1-one; Benzoyls such as benzoin and benzyl; Benzoylalkyl ethers such as benzoinmethyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether and benzoin n-butyl ether; benzophenone, p-methyl Benzoyls such as benzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone; acetophenone, 2,2-dimethoxy-2-phenylacetophenone , 2,2-Diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanol, 2, -Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) ) Phenyl] -acetophenones such as -1-butanone, N, N-dimethylaminoacetophenone; thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone , 2,4-Diisopropylthioxanthone and the like; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone and the like. Anthraquinones; Ketals such as acetophenone dimethyl ketal, benzyl dimethyl ketal; benzoic acid esters such as ethyl-4-dimethylaminobenzoate, 2- (dimethylamino) ethyl benzoate, p-dimethylbenzoic acid ethyl ester; 1,2- Octandione, 1- [4- (Phenylthio)-, 2- (O-benzoyloxime)], Etanone, 1- [9-Ethyl-6- (2-Methylbenzoyl) -9H-Carbazole-3-yl]- , 1- (O-Acetyloxym) and other oxime esters; bis (η5-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-yl)) Phenyl) Titanium, bis (cyclopentadienyl) -bis [2,6-difluoro-3- (2- (1-pyll-1-yl) ethyl) phenyl] Titanosen such as titanium; phenyldisulfide 2-nitrofluorene , Butyloin, anisoin ethyl ether, azobisisobutyronitrile, tetramethylthium disulfide and the like.

The content of the photopolymerization initiator is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin. When the amount is 0.1 part by mass or more, the photocurability of the curable resin composition is good, the film is hard to peel off, and the film properties such as chemical resistance are also good. Further, when the amount is 30 parts by mass or less, the effect of reducing outgas is obtained, the light absorption on the surface of the solder resist coating film is good, and the deep curability is not easily lowered. More preferably, it is 0.1 to 20 parts by mass.

[(G) Photopolymerizable Monomer]
As the photopolymerizable monomer, known ones can be used. Further, the photopolymerizable monomer may be used alone or in combination of two or more.

The photopolymerizable monomer is a compound having an intercarbon multiple bond (double bond and triple bond) in the molecule. Examples of such photopolymerizable monomers include alkyl (meth) acrylates such as 2-ethylhexyl (meth) acrylate and cyclohexyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and the like. Hydroxyalkyl (meth) acrylates; mono- or di (meth) acrylates of alkylene oxide derivatives such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol; hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, di Polyhydric alcohols such as pentaerythritol and trishydroxyethyl isocyanurate or polyvalent (meth) acrylates of these ethylene oxides or propylene oxide adducts; phenols such as phenoxyethyl (meth) acrylates and polyethoxydi (meth) acrylates of bisphenol A. (Meta) acrylates of ethylene oxide or propylene oxide adduct; (meth) acrylates of glycidyl ethers such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, triglycidyl isocyanurate; and melamine (meth) acrylate; etc. Known (meth) acrylates of the above can be mentioned.
In addition, in this specification, (meth) acrylate is a generic term for acrylate, methacrylate and a mixture thereof, and the same applies to other similar expressions.

The content of the photopolymerizable monomer in the curable resin composition of the present invention is not particularly limited, but may be, for example, 5 to 40 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin.

[Other ingredients]
Other components include known additives commonly used in curable resin compositions, such as colorants, thermosetting catalysts, photoinitiator aids, wet dispersants, elastomers, mercapto compounds, urethanization catalysts, and thixochemicals. Agents, adhesion promoters, block copolymers, chain transfer agents, polymerization inhibitors, copper damage inhibitors, antioxidants, rust preventives, organic bentonite, thickeners such as montmorillonite, silicone-based, fluorine-based, polymers Examples thereof include defoaming agents and / or leveling agents such as systems, silane coupling agents such as imidazole, thiazole and triazole, flame retardants such as phosphinates, phosphate ester derivatives, and phosphorus compounds such as phosphazene compounds.

Further, as other components, known heat-reactive components other than the above-mentioned isocyanate compounds can also be mentioned. Examples of such a heat-reactive component include amino resins such as melamine resin, benzoguanamine resin, melamine derivative, and benzoguanamine derivative, cyclocarbonate compound, epoxy compound, oxetane compound, episulfide resin, bismaleimide, and carbodiimide resin. ..

<Use of curable resin composition>
The curable resin composition of the present invention is suitable for forming a permanent coating film such as a solder resist, a coverlay, and an interlayer insulating layer of a printed wiring board or a flexible printed wiring board, and is particularly excellent in low dielectric property. Suitable for forming insulating layers and protective coatings for high-density wiring and printed wiring boards for high frequencies.

<How to use the curable resin composition>
The curable resin composition of the present invention may be used as a dry film or may be used as a liquid. When used as a liquid, it may be one-component or two-component or more.

Next, as an example of the method of using the curable resin composition of the present invention, a method of forming a dry film for solder resist and a method of forming a cured product of the curable resin composition on a substrate will be described. ..

(Dry film)
The curable resin composition of the present invention can also be in the form of a dry film including a support (carrier) film and a resin layer obtained from the curable resin composition formed on the support film. When forming a dry film, the curable resin composition of the present invention is diluted with the above organic solvent to adjust the viscosity to an appropriate level, and a comma coater, a blade coater, a lip coater, a rod coater, a squeeze coater, a reverse coater, and a transferor coater are used. , A gravure coater, a spray coater or the like is applied onto a carrier film to a uniform thickness, and the film is usually dried at a temperature of 50 to 130 ° C. for 1 to 30 minutes to obtain a film. That is, the resin layer is a layer obtained by drying the curable resin composition, in other words, a layer made of solid content in the curable resin composition. The coating film thickness is not particularly limited, but is generally selected as appropriate in the range of 1 to 150 μm, preferably 10 to 60 μm after drying.

As the support film, a plastic film is used, and it is preferable to use a polyester film such as polyethylene terephthalate (PET), a polyimide film, a polyamideimide film, a polypropylene film, and a plastic film such as a polystyrene film. The thickness of the support film is not particularly limited, but is generally appropriately selected in the range of 10 to 150 μm.

After forming the resin layer of the curable resin composition of the present invention on the support film, the cover can be peeled off from the surface of the resin layer for the purpose of preventing dust from adhering to the surface of the resin layer. ) It is preferable to laminate the film. As the peelable protective film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, a surface-treated paper, or the like can be used, and when the protective film is peeled off, the adhesive strength between the resin layer and the support film is increased. However, the adhesive strength between the resin layer and the protective film may be smaller.

In the present invention, the curable resin composition of the present invention may be applied onto the protective film and dried to form a resin layer, and a support film may be laminated on the surface thereof. That is, as the film to which the curable resin composition of the present invention is applied when producing the dry film in the present invention, either a support film or a protective film may be used.

(Cursed product)
The cured product of the present invention is obtained by curing the resin layer of the curable resin composition of the present invention or the dry film of the present invention, and has low dielectric properties (low dielectric constant and low dielectric loss tangent). Has.

(Printed wiring board)
The printed wiring board of the present invention has a curable resin composition of the present invention or a cured product obtained by curing the resin layer of a dry film. As a method for producing a printed wiring board of the present invention, for example, the curable resin composition of the present invention is adjusted to a viscosity suitable for the coating method using the above organic solvent, and a dip coating method is applied on the substrate. After coating by a flow coating method, a roll coating method, a bar coater method, a screen printing method, a curtain coating method, etc., the organic solvent contained in the composition is volatilized and dried (temporarily dried) at a temperature of 60 to 100 ° C. This forms a tack-free resin layer. Further, in the case of a dry film, a resin layer is formed on the base material by laminating the resin layer on the base material with a laminator or the like so as to be in contact with the base material and then peeling off the carrier film.

The base material includes a printed wiring board and a flexible printed wiring board whose circuit is formed of copper or the like in advance, as well as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, and glass cloth / paper epoxy. , Synthetic fiber epoxy, fluororesin / polyethylene / polyimideene ether, polyphenylene oxide / cyanate, etc. are used for high frequency circuit copper-clad laminates, etc., and all grades (FR-4, etc.) of copper-clad laminates are used. Examples thereof include a plate, a metal substrate, a polyimide film, a polyethylene terephthalate film, a polyethylene naphthalate (PEN) film, a glass substrate, a ceramic substrate, a wafer plate, and the like.

The volatile drying performed after applying the curable resin composition of the present invention is carried out in a hot air circulation type drying oven, an IR furnace, a hot plate, a convection oven, etc. It can be carried out by using a method of bringing hot air into countercurrent contact and a method of blowing hot air onto a support from a nozzle).

When the curable resin composition of the present invention is patterned by photolithography, a resin layer is formed on a substrate, and then selectively exposed by active energy rays through a photomask having a predetermined pattern formed, and unexposed. The portion is developed with a dilute alkaline aqueous solution (for example, 0.3 to 3 mass% sodium carbonate aqueous solution) to form a pattern of the cured product. Further, the cured product is adhered by irradiating the cured product with active energy rays and then heat-curing (for example, 100 to 220 ° C.), or by irradiating the cured product with active energy rays after heat curing, or by performing final finish curing (main curing) only by heat curing. It forms a cured film with excellent properties such as properties and hardness.

The exposure machine used for the above-mentioned active energy ray irradiation may be a device equipped with a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, etc., and irradiates ultraviolet rays in the range of 350 to 450 nm. Further, a direct drawing device (for example, a laser direct imaging device that directly draws an image with a laser based on CAD data from a computer) can also be used. The lamp light source or the laser light source of the direct drawing machine may have a maximum wavelength in the range of 350 to 450 nm. The amount of exposure for image formation varies depending on the film thickness and the like, but is generally in the range of 10 to 1000 mJ / cm ² , preferably in the range of 20 to 800 mJ / cm ² .

The development method can be a dipping method, a shower method, a spray method, a brush method, or the like, and the developers include potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, and the like. Alkaline aqueous solutions such as ammonia and amines can be used.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples and Comparative Examples. In the following, "part" and "%" are all based on mass unless otherwise specified.

<Raw material for curable resin composition>
[(A) Carboxyl group-containing resin]
A-1: Resin solution of carboxyl group-containing resin A-1 synthesized later (nonvolatile component 70.6% by mass)
[(B) Isocyanate compound]
B-1: BI-7982 (manufactured by Baxenden Chemicals, blocked isocyanate)
[(C) Fluororesin filler]
C-1: PTFE PF150-PH (manufactured by Nippon Valker Co., Ltd., spherical and substantially spherical, emulsion-polymerized PTFE filler, average particle size 2.6 μm)
[(D) Silica]
D-1: SO-E2 (manufactured by Admatex, spherical silica, average particle size 2.0 μm)
[(E) Organic solvent]
E-1: Diethylene glycol monoethyl ether acetate (solubility parameter 9 or higher)
E-2: Ipsol 150 (manufactured by Idemitsu Kosan, petroleum-based naphtha, solubility parameter less than 9)
[(F) Photopolymerization Initiator]
F-1: Omnirad379 (IGM, alkylphenone-based photopolymerization initiator)
F-2: JMT-784 (Titanocene-based photopolymerization initiator manufactured by DKSH Japan)
[(G) Photopolymerizable Monomer]
G-1: Aronix M-309 (Trimethylol Prohantriacrylate, manufactured by Toagosei Co., Ltd.)
[(H) Other ingredients]
(Wet dispersant)
OFS-6030 (Dow Corning, methacryloxypropyltrimethoxysilane)
(Leveling agent)
Polyflow No.90 (manufactured by Kyoeisha Chemical Co., Ltd.)
(Colorant)
Blue colorant (Pigment Blue 15: 3)
Yellow colorant (Pigment Yellow 147)
(Curing catalyst)
Melamine (antifoaming agent)
KS-66 (manufactured by Shin-Etsu Chemical Co., Ltd.)
(Thermal reactive component)
NC-3000H (manufactured by Nippon Kayaku Co., Ltd., biphenyl novolac modified epoxy resin, epoxy equivalent 290 (g / eq))

<Synthesis of Carboxyl Group-Containing Photosensitive Resin A-1>
Novolac type cresol resin (trade name "Shonol CRG951", manufactured by Showa Denko KK, OH equivalent: 119.4) 119.4 in an autoclave equipped with a thermometer, a nitrogen introduction device and an alkylene oxide introduction device, and a stirring device. A parts by mass, 1.19 parts by mass of potassium hydroxide and 119.4 parts by mass of toluene were introduced, the inside of the system was replaced with nitrogen while stirring, and the temperature was raised by heating. Next, 63.8 parts by mass of propylene oxide was gradually added dropwise, and the mixture was reacted at 125 to 132 ° C. and 0 to 4.8 kg / cm ² for 16 hours. Then, the mixture was cooled to room temperature, and 1.56 parts by mass of 89% phosphoric acid was added to and mixed with this reaction solution to neutralize potassium hydroxide. The non-volatile content was 62.1% and the hydroxyl value was 182.2 mgKOH / g (307). A propylene oxide reaction solution of a novolak-type cresol resin at 0.9 g / eq.) Was obtained. This had an average of 1.08 mol of alkylene oxide added per equivalent amount of phenolic hydroxyl group.
293.0 parts by mass of the alkylene oxide reaction solution of the obtained novolak type cresol resin, 43.2 parts by mass of acrylic acid, 11.53 parts by mass of methanesulfonic acid, 0.18 parts by mass of methylhydroquinone and 252.9 parts by mass of toluene. , Introduced into a reactor equipped with a stirrer, thermometer and air blow tube, air was blown at a rate of 10 ml / min and reacted at 110 ° C. for 12 hours with stirring. As the water produced by the reaction, 12.6 parts by mass of water was distilled off as an azeotropic mixture with toluene. Then, the mixture was cooled to room temperature, the obtained reaction solution was neutralized with 35.35 parts by mass of a 15% aqueous sodium hydroxide solution, and then washed with water. Then, toluene was distilled off while substituting 118.1 parts by mass of diethylene glycol monoethyl ether acetate with an evaporator to obtain a novolak type acrylate resin solution. Next, 332.5 parts by mass of the obtained novolak-type acrylate resin solution and 1.22 parts by mass of triphenylphosphine were introduced into a reactor equipped with a stirrer, a thermometer and an air blow tube, and air was introduced at 10 ml / min. With stirring, 60.8 parts by mass of tetrahydrophthalic anhydride was gradually added, reacted at 95 to 101 ° C. for 6 hours, cooled, and then taken out. In this way, a solution of a photosensitive carboxyl group-containing resin having a non-volatile component of 70.6% by mass and a solid acid value of 87.7 mgKOH / g was obtained.

<Preparation of curable resin composition according to Examples and Comparative Examples>
Based on the component compositions shown in Table 1, each component was blended, premixed with a stirrer, and then kneaded and dispersed to prepare a curable resin composition according to Examples and Comparative Examples.

<Evaluation>
For each composition thus obtained, the dielectric constant (Dk), the dielectric loss tangent (Df) and the screen printability were evaluated based on the following evaluation methods. The results of these evaluations are shown in Table 1.

[Evaluation of permittivity (Dk) and dielectric loss tangent (Df)]
(Creation of test piece)
The curable resin compositions obtained in Examples and Comparative Examples were appropriately diluted with methyl ethyl ketone, and then using an applicator, a PET film (manufactured by Toray Industries, Inc., FB) was used so that the dried film had a thickness of 25 μm. -50: 16 μm) and dried at 80 ° C. for 30 minutes to obtain a dry film. The obtained dry film was pressed on an electrolytic copper foil (manufactured by Furukawa Electric Co., Ltd.) having a thickness of 9 μm using a vacuum laminator (MVLP-500 manufactured by Meiki Seisakusho Co., Ltd.) at a pressure of 0.8 MPa. , 70 ° C., 1 minute, vacuum degree: 133.3 Pa. The dry film laminated on the copper foil was subjected to solid exposure at the optimum exposure amount using an exposure apparatus equipped with a high-pressure mercury lamp (short arc lamp), and the PET film was peeled off. The dry film was heat-laminated again on the exposed dry film, and then solid-exposed at the optimum exposure amount. By repeating laminating and exposure twice, a dry film layer having a thickness of 50 μm was formed on the copper foil. The copper foil on which the dry film layer was formed in this manner was irradiated with ultraviolet rays under the condition of an integrated exposure amount of 1000 mJ / cm2 in a UV conveyor furnace, and then heated at 150 ° C. for 60 minutes to cure the dry film layer. Next, the copper foil with a dry film layer was etched and removed with an etching solution having a composition of 340 g / l cupric chloride and a free hydrochloric acid concentration of 51.3 g / l, washed thoroughly with water, and dried. A test piece made of a cured film having a thickness of 50 μm was prepared.

[Measurement of permittivity (Dk) and dielectric loss tangent (Df)]
The test piece thus produced was evaluated by measuring the dielectric constant and the dielectric loss tangent at 10 GHz using an SPDR dielectric resonator and a network analyzer (both manufactured by Agilent).

[Evaluation of screen printability]
The curable resin compositions obtained in Examples and Comparative Examples were screen-printed on a copper substrate. The printability of the screen was evaluated according to the following criteria.
⊚: When printing, a coating film could be formed neatly on the substrate without transfer defects.
〇: There was a slight leveling defect when printing, but it was at a level where there was no problem in practical use.
X: When printing, the coating film could not be formed due to poor transfer.

As is clear from the evaluation results shown in the above table, in each example, the improved fluidity of the composition provides excellent screen printability and cure with reduced dielectric constant and dielectric loss tangent. It was confirmed that the sex resin composition, the dry film and the cured product were obtained.

Claims (4)

A curable resin composition containing (A) a carboxyl group-containing resin, (B) an isocyanate compound, (C) a fluororesin filler, (D) silica, and (E) an organic solvent.
A curable resin composition , wherein the compounding ratio of the fluororesin filler (C) to the silica (D) is 2: 8 to 7: 3 in mass ratio . A dry film having a resin layer obtained from the curable resin composition according to claim 1. A cured resin composition according to claim 1, or a cured product obtained by curing the resin layer of the dry film according to claim 2. A printed wiring board comprising the cured product according to claim 3.