JP2019179200A - Curable resin composition, dry film, cured product and printed wiring board - Google Patents

Abstract

To provide a curable resin composition having reduced dielectric constants and dielectric loss tangents while maintaining excellent flowability and coatability.SOLUTION: A curable resin composition contains (A) a carboxyl group-containing resin, (B) an isocyanate compound, (C) a fluorine resin filler, (D) silica, and (E) an organic solvent.SELECTED DRAWING: None

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

  Generally, in printed wiring boards, from the viewpoints of heat resistance and electrical insulation, it is mainly composed of modified epoxy acrylate compounds and epoxy resins for interlayer insulation materials and solder resist materials, and also contains additional components such as fillers. Resin compositions are widely used.

  On the other hand, in the information 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 with printed wiring board materials, transmission loss in information transmission during communication There is a demand for the development of high-frequency compatible materials with reduced noise. In other words, this transmission loss is generally expressed as the product of the dielectric constant and dielectric loss tangent of the cured product of the resin composition that constitutes the interlayer insulating material and solder resist, so both the dielectric constant and dielectric loss tangent are reduced. It was necessary to develop materials to be used.

  On the other hand, as a method for reducing both the dielectric constant and dielectric loss tangent of printed wiring board materials, there is a method of blending a large amount of a filler having a low dielectric constant or dielectric loss tangent with the resin composition constituting the interlayer insulating material or solder resist. Proposed.

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

Japanese Patent Laid-Open No. 2006-166347

  However, when a large amount of a filler having a low 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 such filler and other components From the difference in polarity (electrical bias of molecular structure), the thixotropy of the composition is increased, the fluidity is remarkably lowered, and thus new problems such as the inability to perform the coating work by screen printing and the like arise. It was.

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

  The present inventors diligently studied to realize the above object. As a result, in addition to the point that the resin component is a curing system of a carboxyl group-containing resin and an isocyanate compound, the fluidity and coating properties of the material are deteriorated by using the filler component as a combination of a fluororesin filler and silica. The inventors have found that both the dielectric constant and the dielectric loss tangent of the cured product can be reduced, and have completed the present invention.

That is, the curable resin composition of the present invention comprises (A) a carboxyl group-containing resin, (B) an isocyanate compound, (C) a fluororesin filler, (D) silica, and (E) an organic solvent. To do.
The dry film of the present invention has a resin layer obtained from the curable resin composition.
The cured product of the present invention is obtained by curing the curable resin composition or the resin layer of the dry film.
The printed wiring board of this invention has the said hardened | cured material, It is characterized by the above-mentioned.

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

  Hereinafter, although the curable resin composition of this invention is demonstrated concretely, this invention is not limited to these at all.

  In addition, when an isomer exists in the described compound, all isomers that can exist 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.
Moreover, the curable resin composition of this invention may further contain (F) photoinitiator and (G) photopolymerizable monomer as a preferable component.
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, a known resin can be used. Moreover, carboxyl group-containing resin may be used individually by 1 type, and may be used in combination of 2 or more type.

  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). Resin). The ethylenically unsaturated double bond is preferably derived from acrylic acid or methacrylic acid or a derivative thereof. In the case of using only a carboxyl group-containing resin having no ethylenically unsaturated double bond in the molecule, in order to make the composition photocurable, a compound having a plurality of carbon-carbon unsaturated bonds to be described later That is, it is necessary to use a photopolymerizable monomer in combination.

  Specific examples of the carboxyl group-containing resin include the following compounds (any of oligomers and polymers).

  (I) A carboxyl group-containing resin obtained by copolymerization of an unsaturated carboxylic acid such as (meth) acrylic acid and 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, aromatic diisocyanates, and carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, polycarbonate polyols, and polyethers A carboxyl group-containing urethane resin by a polyaddition 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 ( A carboxyl group-containing photosensitive urethane resin obtained by polyaddition reaction of (meth) acrylate or a partially acid anhydride modified product 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, and the terminal ( (Meth) acrylic 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 added in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate. A carboxyl group-containing photosensitive urethane resin obtained by adding a compound having a terminal (meth) acrylate.

  (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 present in the side chain.

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

  (VIII) Two bases such as phthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride are reacted with a dicarboxylic acid such as adipic acid, phthalic acid, and hexahydrophthalic acid on a bifunctional oxetane resin. A carboxyl group-containing polyester resin to which an 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, and then reacting with the alcoholic hydroxyl group of the resulting reaction product, maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, adipine A carboxyl group-containing resin obtained by reacting a polybasic acid anhydride such as an acid.

  (X) Reaction product obtained by reacting a compound 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 product with a polybasic acid anhydride.

  (XI) An unsaturated group-containing monocarboxylic acid is reacted 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 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 suitably in the range of 30 to 150 mgKOH / g, 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 developability is improved when pattern formation is performed by photolithography. If it is 150 mgKOH / g or less, the polar group is reduced and low dielectric properties are obtained. When pattern formation is performed by photolithography, sufficient resistance to the developer in the exposed area is obtained, and a normal resist pattern is ensured. This is preferable because it can be drawn on the screen.

  The weight average molecular weight of the carboxyl group-containing resin varies depending on the resin skeleton, but is generally 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 cured film has good flexibility and adhesion, and developability is good when pattern formation is performed by photolithography. Further, when the weight average molecular weight is 150,000 or less, the heat resistance and insulation of the cured film and the storage stability of the composition 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, carboxyl group-containing resins synthesized using phenol compounds such as the carboxyl group-containing resins (X) and (XI) as starting materials are HAST resistance (super accelerated life test) and PCT resistance (saturated steam pressure test). ), It can be preferably used.

  (A) Although the compounding quantity of carboxyl group-containing resin is not specifically limited, It is 10-95 mass% per curable resin composition in conversion of a non-volatile component, Preferably what is necessary is just to be 10-80 mass%.

[(B) Isocyanate compound]
A well-known thing can be used for an isocyanate compound. Moreover, an isocyanate compound may be used individually by 1 type, and may be used in combination of 2 or more type.

  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; Alicyclic polyisocyanates such as heptane triisocyanate; and adducts of the isocyanate compounds listed above, Yuretto body and isocyanurate products thereof.

  In the present invention, the isocyanate compound is preferably a blocked isocyanate compound from the viewpoint that workability is improved due to excellent storage stability.

  As the blocked isocyanate compound, an addition reaction product of an isocyanate compound and an isocyanate blocking agent can be used. As an isocyanate compound which can react with an isocyanate blocking agent, the above-mentioned polyisocyanate compound etc. are mentioned, for example. 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 methylene 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 Ether, methyl glycolate, butyl glycolate, diacetone alcohol, milk Alcohol-based blocking agents such as methyl and ethyl lactate; oxime-based blocking agents such as formaldehyde oxime, acetaldoxime, acetoxime, methylethyl ketoxime, diacetyl monooxime, cyclohexane oxime; butyl mercaptan, hexyl mercaptan, t-butyl mercaptan, thiophenol, Mercaptan block agents such as methylthiophenol and ethylthiophenol; Acid amide block agents such as acetic acid amide and benzamide; Imide block agents such as succinimide and maleic imide; Amines such as xylidine, aniline, butylamine and dibutylamine Blocking agents; imidazole blocking agents such as imidazole and 2-ethylimidazole; imine blocking agents such as methyleneimine and propyleneimine A pyrazole block agent such as dimethylpyrazole; a maleate ester block agent such as diethylmaleic acid; and the like.

  As a block isocyanate compound, for example, Sumidur (registered trademark) BL-3175, BL-4165, BL-1100, BL-1265, Desmodur (registered trademark) TPLS-2957, TPLS-2062, TPLS are commercially available. -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 ( Asahi Kasei Chemica 'S Ltd.), TRIXENE BI 7982, the 7950, the 7951, the 7960, the 7961, can be mentioned (Baxeneden Chemicals Limited Co.), among others, Duranate SBN-70D, is TRIXENE BI 7982 preferred. Sumijoules BL-3175 and BL-4265 are obtained using methyl ethyl oxime as a blocking agent.

  The compounding quantity of an isocyanate compound is 0.01-20 mass parts with respect to 100 mass parts of carboxyl group-containing resin in conversion of a non-volatile component, Preferably it is 5-15 mass parts. If the blending amount is within the range of the above-mentioned parts by mass, a good permanent film can be obtained as a circuit protection for the printed wiring board by the curing reaction with the carboxyl group-containing resin.

[(C) Fluororesin filler]
A well-known thing can be used as a fluororesin filler. Moreover, a fluororesin filler may be used individually by 1 type, and may be used in combination of 2 or more type.

  Fluororesin includes polytetrafluoroethylene (PTFE), tetrafluoroethylene / ethylene copolymer (ETFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene Examples thereof include a copolymer (FEP), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF).

  The shape of the primary particles of the fluororesin filler is not particularly limited, and examples thereof include indeterminate shapes and spherical or substantially granular shapes. Among these, spherical and substantially granular shapes 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, more preferably 8% by mass or more and 35% by mass or less per curable resin composition in terms of nonvolatile components.

  The above-mentioned fluororesin filler is preferably a PTFE filler. Although it does not specifically limit in this PTFE filler, Suspension polymerization type and an emulsion polymerization type are mentioned, The emulsion polymerization type PTFE filler which is excellent in a dispersibility is more preferable.

  Here, in this specification, the average particle diameter is not only the particle diameter of the primary particles but also the average particle diameter (D50) including the particle diameter of the secondary particles (aggregates), and is measured by a laser diffraction method. D50 value obtained. An example of a measuring apparatus using the laser diffraction method is Microtrac MT3300EXII manufactured by Nikkiso Co., Ltd. Note that the maximum particle size (D100) and the particle size (D10) can be measured in the same manner using the above-described apparatus.

[(D) Silica]
Any known silica can be used as the filler for electronic materials. Moreover, a silica may be used individually by 1 type and may be used in combination of 2 or more type.

  Examples of the silica include fused silica, spherical silica, amorphous silica, crystalline silica, finely divided silica, and the like. Among these, 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 a true sphere. Suitable spherical silica includes, for example, those having a sphericity measured as follows of 0.8 or more, but are not limited thereto.

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

  Silica is preferably 0.1 μm to 50 μm, more preferably the average particle size as the average particle size obtained from the volume average particle size distribution measurement result measured by the laser diffraction particle size distribution measuring device. 0.2 μm to 20 μm.

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

  As the silica, either silica that has not been surface-treated or surface-treated silica can be used, and it is preferable to use silica that has been surface-treated from the viewpoint of fluidity of the composition. In such a surface treatment of silica, silica in a surface-treated state is blended in advance, or silica in a surface-untreated product and a surface treatment agent are blended separately to surface-treat silica in the composition. Also good. The surface treatment agent is not particularly limited and may be a known one, 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, coupling agents such as silane, titanate, aluminate and zircoaluminate can be used. Of these, silane coupling agents are preferred. Examples of such silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N- (2-aminomethyl) -3-aminopropylmethyldimethoxysilane, 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, and these can be used alone or in combination. The processing amount of these silane coupling agents is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of silica. In the present invention, a reactive functional group derived from a coupling agent applied to silica is not included in a compound having a photocurable reactive group or a thermosetting functional group.

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

  The blending amount of the fluororesin filler and silica described above is preferably such that the blending ratio of the fluororesin filler and silica is preferably in the range of 2: 8 to 7: 3, more preferably 3: 7 to 6: 4. . If it is the range of the said content rate and compounding ratio, the fluidity | liquidity as a composition will improve and the reduction effect of a dielectric constant and a dielectric loss tangent will be acquired.

[(E) Organic solvent]
As the organic solvent, known ones can be used, and they are used for the purpose of preparing the composition and adjusting the viscosity when applied on the printed wiring board. Therefore, the content of the organic solvent can be appropriately changed according to the purpose. Moreover, an organic solvent may be used individually by 1 type, and may be used in combination of 2 or more type. Among these, it is preferable to use at least one organic solvent having a solubility parameter of less than 9. By including an organic solvent having a solubility parameter of less than 9 in the curable resin composition, the dispersibility of the fluororesin filler having a low polarity and the fluidity of the composition of the present invention are improved. In the present specification, the solubility parameter is calculated based on the Fedors method.

  Examples of the organic solvent having a solubility 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, 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 Butyl ether acetate, diethylene glycol monobutyl ether acetate, petroleum naphtha (Idemitsu Kosan) Ltd. Ipuzoru 100 include Ipuzoru 150), and the like.

  Examples of the organic solvent having a solubility 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, 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-methoxybutanol, diethylene glycol monoethyl ether, n-propyl alcohol, 1,3-butylene glycol , Etc.

[(F) Photopolymerization initiator]
Known photopolymerization initiators can be used. Moreover, a photoinitiator may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the photopolymerization initiator 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, bis- (2,4,6- Trimethylbenzoyl) -phenylphosphine oxide 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenyl Monoacylphosphine oxides such as phosphine oxide, pivaloylphenylphosphinic acid isopropyl ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide; ethyl phenyl (2,4,6-trimethylbenzoyl) phosphinate; 1-hydroxy-cyclohexyl phenyl ketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydro Ci-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, 2-hydroxy-2-methyl-1-phenylpropane- Hydroxyacetophenones such as 1-one; Benzoins such as benzoin and benzyl; Benzoin alkyl ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether and benzoin n-butyl ether; Benzophenone and p-methyl Benzophenones, 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-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 other acetophenones; thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone 2,4-diisopropylthioxanthone Thioxanthones; anthraquinones such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone; acetophenone dimethyl ketal, benzyl Ketals such as dimethyl ketal; benzoic acid esters such as ethyl-4-dimethylaminobenzoate, 2- (dimethylamino) ethylbenzoate, p-dimethylbenzoic acid ethyl ester; 1,2-octanedione, 1- [4- (Phenylthio)-, 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime) ) Bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) phenyl) titanium, bis (cyclopentadienyl) ) -Bis [2,6-difluoro-3- (2- (1-pyr-1-yl) ethyl) phenyl] titanium and the like; phenyl disulfide 2-nitrofluorene, butyroin, anisoin ethyl ether, azobis Examples include isobutyronitrile and tetramethylthiuram disulfide.

  It is preferable that content of a photoinitiator is 0.1-30 mass parts with respect to 100 mass parts of carboxyl group-containing resin. In the case of 0.1 parts by mass or more, the photocurability of the curable resin composition is good, the film is difficult to peel off, and the film properties such as chemical resistance are also good. Moreover, when it is 30 parts by mass or less, an effect of reducing outgas is obtained, light absorption on the surface of the solder resist coating film is good, and deep part curability is hardly lowered. More preferably, it is 0.1-20 mass parts.

[(G) Photopolymerizable monomer]
A well-known thing can be used as a photopolymerizable monomer. Moreover, a photopolymerizable monomer may be used individually by 1 type, and may be used in combination of 2 or more type.

The photopolymerizable monomer is a compound having a carbon-carbon multiple bond (double bond and triple bond) in the molecule. Examples of such a photopolymerizable monomer 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 polyvalents of these ethylene oxide or propylene oxide adducts (Meth) acrylates; (meth) acrylates of ethylene oxide or propylene oxide adducts of phenols such as phenoxyethyl (meth) acrylate and polyethoxydi (meth) acrylate of bisphenol A; glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, Known (meth) acrylates such as (meth) acrylates of glycidyl ether such as triglycidyl isocyanurate; and melamine (meth) acrylate;
In addition, in this specification, (meth) acrylate is a term which generically refers to acrylate, methacrylate and a mixture thereof, and the same applies to other similar expressions.

  Although content of the photopolymerizable monomer in the curable resin composition of this invention is not specifically limited, For example, what is necessary is just to be 5-40 mass parts etc. with respect to 100 mass parts of carboxyl group-containing resin.

[Other ingredients]
As other components, known additives generally used in curable resin compositions, such as colorants, thermosetting catalysts, photoinitiator aids, wetting and dispersing agents, elastomers, mercapto compounds, urethanization catalysts, thixotropy Agent, adhesion promoter, block copolymer, chain transfer agent, polymerization inhibitor, copper damage inhibitor, antioxidant, rust inhibitor, organic bentonite, montmorillonite and other thickeners, silicone-based, fluorine-based, polymer Examples include antifoaming agents and / or leveling agents, silane coupling agents such as imidazole, thiazole, and triazole, flame retardants such as phosphinates, phosphoric acid ester derivatives, and phosphorus compounds such as phosphazene compounds.

  Moreover, as another component, well-known heat-reactive components other than the isocyanate compound mentioned above are also mentioned. Examples of such heat-reactive components include amino resins such as melamine resins, benzoguanamine resins, melamine derivatives, and benzoguanamine derivatives, cyclocarbonate compounds, epoxy compounds, oxetane compounds, episulfide resins, bismaleimides, carbodiimide resins, and the like. .

<Use of curable resin composition>
The curable resin composition of the present invention is suitable for the formation of permanent coatings such as solder resists, coverlays, interlayer insulation layers of printed wiring boards and flexible printed wiring boards, and in particular, because of its excellent low dielectric properties, It is suitable for forming insulating layers and protective coatings for high-density wiring and high-frequency printed wiring boards.

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

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

(Dry film)
The curable resin composition of this invention can also be made into the form of the dry film provided with the support (carrier) film and the resin layer obtained from the said curable resin composition formed on this support film. When forming a dry film, the curable resin composition of the present invention is diluted with the above organic solvent to adjust to an appropriate viscosity, and is applied to a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater. A film can be obtained by applying a uniform thickness on a carrier film with a gravure coater, spray coater or the like, and drying usually at a temperature of 50 to 130 ° C. for 1 to 30 minutes. That is, the resin layer is a layer obtained by drying the curable resin composition. In other words, the resin layer is a layer made of a solid content in the curable resin composition. Although there is no restriction | limiting in particular about a coating film thickness, Generally, it is 1-150 micrometers in the film thickness after drying, Preferably it selects suitably in the range of 10-60 micrometers.

  A plastic film is used as the support film, and a plastic film such as a polyester film such as polyethylene terephthalate (PET), a polyimide film, a polyamideimide film, a polypropylene film, or a polystyrene film is preferably used. Although there is no restriction | limiting in particular about the thickness of a support film, Generally, it selects suitably in the range of 10-150 micrometers.

  After forming the resin layer of the curable resin composition of the present invention on the support film, the protective layer (cover) that 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 films. As the peelable protective film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, a surface-treated paper, etc. can be used, and when the protective film is peeled off, the adhesive force between the resin layer and the support film As long as the adhesive strength between the resin layer and the protective film is smaller.

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

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

(Printed wiring board)
The printed wiring board of the present invention has a cured product obtained by curing the curable resin composition of the present invention or the resin layer of the 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 a coating method using the organic solvent, and a dip coating method is performed on a substrate. After coating by a method such as a flow coating method, a roll coating method, a bar coater method, a screen printing method, or a curtain coating method, the organic solvent contained in the composition is volatilized and dried (temporary drying) at a temperature of 60 to 100 ° C. Thus, a tack-free resin layer is formed. Moreover, in the case of a dry film, after bonding together on a base material so that a resin layer may contact a base material with a laminator etc., a resin layer is formed on a base material by peeling a carrier film.

  Examples of the base material include printed wiring boards and flexible printed wiring boards that have been previously formed with copper or the like, paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy. It is made of materials such as copper-clad laminates for high-frequency circuits using synthetic fiber epoxy, fluororesin, polyethylene, polyphenylene ether, polyphenylene oxide, cyanate, etc., and copper-clad laminates of all grades (FR-4 etc.) 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, and a wafer plate.

  Volatile drying performed after the application of the curable resin composition of the present invention is performed in a dryer using a hot air circulation drying furnace, an IR furnace, a hot plate, a convection oven or the like (equipped with a heat source of an air heating method using steam). The method can be carried out using a method in which hot air is brought into countercurrent contact and a method in which the hot air is blown onto the support.

  When patterning the curable resin composition of the present invention by photolithography, after forming a resin layer on the substrate, it is selectively exposed with active energy rays through a photomask on which a predetermined pattern is formed, and unexposed. The part is developed with a dilute alkaline aqueous solution (for example, 0.3 to 3% by mass aqueous sodium carbonate solution) to form a cured product pattern. Furthermore, the cured product is irradiated with active energy rays and then heat-cured (for example, 100 to 220 ° C.), irradiated with active energy rays after heat-curing, or subjected to final finish curing (main-curing) only by heat-curing, thereby allowing adhesion. A cured film having excellent properties such as properties and hardness is formed.

As an exposure machine used for the active energy ray irradiation, a high-pressure mercury lamp lamp, an ultra-high pressure mercury lamp lamp, a metal halide lamp, a mercury short arc lamp, and the like may be used as long as the apparatus irradiates ultraviolet rays in a range of 350 to 450 nm. Furthermore, a direct drawing apparatus (for example, a laser direct imaging apparatus that directly draws an image with a laser using CAD data from a computer) can also be used. The lamp light source or 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 10 to 1000 mJ / cm ² , preferably 20 to 800 mJ / cm ² .

  The developing method can be a dipping method, a shower method, a spray method, a brush method, etc., and as a developing solution, potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, Alkaline aqueous solutions such as ammonia and amines can be used.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not restrict | limited by these Examples and a comparative example. In the following description, “parts” and “%” are all based on mass unless otherwise specified.

<Raw material of curable resin composition>
[(A) Carboxyl group-containing resin]
A-1: Resin solution of carboxyl group-containing resin A-1 synthesized later (non-volatile 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 Valqua Co., Ltd., spherical and substantially spherical, emulsion polymerization type PTFE filler, average particle size 2.6 μm)
[(D) Silica]
D-1: SO-E2 (manufactured by Admatechs, spherical silica, average particle size 2.0 μm)
[(E) Organic solvent]
E-1: Diethylene glycol monoethyl ether acetate (dissolution parameter 9 or more)
E-2: Ipsol 150 (manufactured by Idemitsu Kosan Co., Ltd., petroleum naphtha, solubility parameter less than 9)
[(F) Photopolymerization initiator]
F-1: Omnirad 379 (manufactured by IGM, alkylphenone photopolymerization initiator)
F-2: JMT-784 (manufactured by DKSH Japan, titanocene photopolymerization initiator)
[(G) Photopolymerizable monomer]
G-1: Aronix M-309 (manufactured by Toa Gosei Co., Ltd., trimethylolprohantriacrylate)
[(H) Other ingredients]
(Wet dispersant)
OFS-6030 (Dow Corning, methacryloxypropyltrimethoxysilane)
(Leveling agent)
Polyflow No. 90 (manufactured by Kyoeisha Chemical Co., Ltd.)
(Coloring agent)
Blue colorant (Pigment Blue 15: 3)
Yellow colorant (Pigment Yellow 147)
(Curing catalyst)
Melamine (antifoam)
KS-66 (manufactured by Shin-Etsu Chemical Co., Ltd.)
(Thermally reactive component)
NC-3000H (Nippon Kayaku Co., Ltd., biphenyl novolak modified epoxy resin, epoxy equivalent 290 (g / eq))

<Synthesis of carboxyl group-containing photosensitive resin A-1>
In an autoclave equipped with a thermometer, a nitrogen introduction device / alkylene oxide introduction device, and a stirring device, a novolac-type cresol resin (trade name “Shonol CRG951”, manufactured by Showa Denko KK, OH equivalent: 119.4) 119.4 Part by mass, 1.19 parts by mass of potassium hydroxide and 119.4 parts by mass of toluene were introduced, the system was purged with nitrogen while stirring, and the temperature was raised. Next, 63.8 parts by mass of propylene oxide was gradually added dropwise and reacted at 125 to 132 ° C. and 0 to 4.8 kg / cm ² for 16 hours. Thereafter, the mixture was cooled to room temperature, and 1.56 parts by mass of 89% phosphoric acid was added to and mixed with the reaction solution to neutralize potassium hydroxide. The nonvolatile content was 62.1% and the hydroxyl value was 182.2 mgKOH / g (307 0.9 g / eq.) Of a novolac-type cresol resin propylene oxide reaction solution. This was an average of 1.08 moles of alkylene oxide added per equivalent of phenolic hydroxyl group.
293.0 parts by mass of the resulting novolak-type cresol resin alkylene oxide reaction solution, 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 Then, it was introduced into a reactor equipped with a stirrer, a thermometer and an air blowing tube, and air was blown at a rate of 10 ml / min, and the reaction was carried out at 110 ° C. for 12 hours while stirring. The water produced | generated by reaction distilled 12.6 mass parts water as an azeotrope with toluene. Then, it cooled to room temperature and neutralized the obtained reaction solution with 35.35 mass parts of 15% sodium hydroxide aqueous solution, and then washed with water. Thereafter, toluene was distilled off while substituting 118.1 parts by mass of diethylene glycol monoethyl ether acetate with an evaporator to obtain a novolak acrylate resin solution. Next, 332.5 parts by mass of the resulting novolak 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 blowing tube, and air was supplied at 10 ml / min. While stirring and stirring, 60.8 parts by mass of tetrahydrophthalic anhydride was gradually added, reacted at 95 to 101 ° C. for 6 hours, cooled, and 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 content acid value of 87.7 mgKOH / g was obtained.

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

<Evaluation>
Each composition thus obtained was evaluated for dielectric constant (Dk), dielectric loss tangent (Df), and screen printability based on the following evaluation methods. These evaluation results are shown in Table 1.

[Evaluation of dielectric constant (Dk) and dielectric loss tangent (Df)]
(Creation of specimen)
The curable resin compositions obtained in Examples and Comparative Examples were appropriately diluted with methyl ethyl ketone, respectively, and then an PET film (manufactured by Toray Industries, Inc., FB) was used so that the film thickness after drying was 25 μm using an applicator. −50: 16 μm) and dried at 80 ° C. for 30 minutes to obtain a dry film. The obtained dry film was applied on a 9 μm thick electrolytic copper foil (manufactured by Furukawa Electric Co., Ltd.) using a vacuum laminator (manufactured by Meiki Seisakusho Co., Ltd., MVLP-500). , 70 ° C., 1 minute, vacuum lamination: 133.3 Pa. The dry film laminated on the copper foil was subjected to solid exposure with an 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 exposure was performed with an optimum exposure amount. Lamination and exposure were repeated twice to form a dry film layer having a thickness of 50 μm on the copper foil. The copper foil thus formed with the dry film layer was irradiated with ultraviolet rays under a condition of an integrated exposure amount of 1000 mJ / cm 2 in a UV conveyor furnace, and then heated at 150 ° C. for 60 minutes to cure the dry film layer. Next, the copper foil is removed from the copper foil with a dry film layer using an etching solution having a composition of cupric chloride of 340 g / l and free hydrochloric acid concentration of 51.3 g / l, sufficiently washed with water and dried. A test piece made of a cured film having a thickness of 50 μm was prepared.

[Measurement of dielectric constant (Dk) and dielectric loss tangent (Df)]
The test piece thus produced was evaluated by measuring the dielectric constant and 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 screen printability was evaluated according to the following criteria.
(Double-circle): When printing, the coating film was able to be formed finely on the base material without the transfer defect.
◯: There was a slight leveling defect when printed, but it was at a level that would not interfere with practical use.
X: When printing, a coating film could not be formed due to transfer failure.

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

Claims (4)

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