JP5787516B2 - Curable resin composition, cured product thereof, and printed wiring board - Google Patents

Description

  The present invention relates to a curable resin composition, a cured product using the same, and a printed wiring board.

  A solder resist pattern for printed wiring boards is generally formed by applying and drying a curable resin composition on a circuit-formed substrate to form a dry coating film of the solder resist, and then exposing the photo tool to vacuum contact. Thereafter, it is formed by developing (see Patent Document 1).

  At this time, if the dry coating is not sufficiently dry to the touch, it will be in close contact with the phototool during contact exposure, and after exposure, the phototool cannot be peeled off or the dry coating will peel off from the substrate. Occurs.

  In recent years, built-up substrates that perform minute drilling with a laser are employed in high-density printed wiring boards. In such a built-up wiring board, there are innumerable minute holes (blind vias, laser vias) having a diameter of 20 μm to 200 μm and a depth of 20 μm to 100 μm on the surface layer. Solder resist is tented in the hole. And, when it repels after drying, there arises a problem that the resist is thin only around the hole.

Thus, in the curable resin composition, the problems caused by insufficient dryness of the touch of the coated film after drying and the problem of coating properties such as tenting to minute holes have not been solved yet. Is the actual situation.
JP 2000-7974 (Claims)

  An object of the present invention is to provide a curable resin composition capable of improving dryness to touch and coating properties after drying, a cured product using the same, and a printed wiring board.

  In order to solve the above problems, a curable resin composition of one embodiment of the present invention is a resin composition for a printed wiring board having a minute hole in a surface layer of a substrate, and includes a lactate ester, a carboxyl group-containing resin, and It is characterized by containing a photopolymerization initiator.

With such a configuration, it is possible to improve the touch-drying and coating properties after coating and drying on the substrate, in particular, prevention of repellency in a printed wiring board having minute holes in the surface layer of the substrate, and sufficient deep curing. It becomes possible to obtain a curable resin composition having properties. The lactic acid ester is preferably a natural product-derived L-lactic acid ester, so that the influence on the environment and the human body can be reduced from the environmental aspect of fossil fuel depletion and CO ₂ emission reduction. By diluting the viscosity of the curable resin composition to 0.1 to 250 dPa · s with this lactic acid ester, the coating property and coating property (prevention of repellency) are improved. In particular, the present invention is effective when a minute hole is formed in the surface layer of the substrate.

  Moreover, by including a carboxyl group-containing resin, it is possible to impart alkali developability to the resin composition of the present invention and to perform high-definition development.

  The cured product or printed wiring board of one embodiment of the present invention is a curable resin having a viscosity of 0.1 to 250 dPa · s diluted with a lactic acid ester on a substrate, in particular, on a substrate in which minute holes are formed in the surface layer. It is characterized by having a pattern formed by exposing, developing, and curing a dry coating film formed by applying and drying the composition. Further, this exposure is preferably contact exposure.

  With such a configuration, it is possible to obtain a cured product or printed wiring board having a pattern with high insulation and heat resistance that is sufficiently cured to a deep part by suppressing coating defects to minute holes and unevenness of film thickness due to repelling. Is possible.

  In the present invention, a minute hole means a hole (blind via or laser via) of φ20 μm to φ200 μm, and the depth direction is not particularly limited. In other words, the depth direction is applied in a wide range from a shallow hole having a depth of several μm to a hole having a depth of 100 μm.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to improve the touch-drying property after drying, and the coating property with respect to a micro hole. As a result, even if contact exposure is performed, peeling of the pattern from the substrate is suppressed, so that a higher definition pattern can be formed.

  In addition, it is possible to suppress the coating failure to minute holes and the unevenness of the film thickness due to repellency and to cure sufficiently to the deep part.

  Furthermore, according to the present invention, it is possible to form a pattern with high insulation and heat resistance that is sufficiently hardened to a deep part while suppressing coating defects in minute holes and uneven film thickness due to repellency.

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, embodiments of the present invention will be described.

  The curable resin composition of this embodiment includes a lactic acid ester, a carboxyl group-containing resin, and a photopolymerization initiator.

  Such a configuration is less likely to cause repellency after coating and drying on a substrate with a minute hole when a lactic acid ester is used as a diluent in a curable resin composition such as an alkali development type solder resist. This is based on the new knowledge.

  For example, as shown in FIG. 1A, the repellency phenomenon may occur when a curable resin composition 13 is applied and dried after forming a copper circuit 12 in which minute holes 12a are formed on a substrate 11. As shown in FIG. 1B, this is a phenomenon that the film thickness around the minute hole 12a of the copper circuit 12 becomes thin. The reason that the repellency phenomenon is reduced when a lactic acid ester is used as a diluent is considered to be related to the solubility of the lactic acid ester with the resin. That is, the lactic acid ester has a lower dilution efficiency than the other general-purpose solvents with respect to the resin component of the curable resin composition. Therefore, when the curable resin composition is diluted to a usable viscosity, the resin solid content relative to the solvent is relatively reduced. Accordingly, such a curable resin composition has a small resin solid content and is applied thickly on a minute hole and on a circuit to ensure an appropriate dry film thickness on the circuit. As described above, when a lactic acid ester is used as a diluent, the repellency phenomenon is considered to be suppressed even when the dry coating film is a thin film as a result of increasing the coating thickness above the minute holes as compared with other general-purpose solvents.

  Here, as shown to FIG. 2A, even if it is a curable resin composition which does not contain a lactic acid ester, by thickening the application | coating thickness of the curable resin composition 13 on the micro hole 12a, it shows to FIG. 2B. As such, the repelling phenomenon can be suppressed. However, in this case, there is a problem that the film thickness of portions other than the minute holes after drying and curing is also increased.

  In this regard, by using the curable resin composition containing the lactic acid ester of the present embodiment, as shown in FIG. 3A, even if the coating thickness of the curable resin composition 13 on the minute hole 12a is increased, As shown in 3B, the thickness of the portion other than the minute holes 12a after drying and curing of the curable resin composition 13 can be reduced, and the repellency phenomenon can be suppressed.

  At this time, it is preferable to adjust the viscosity of the curable resin composition of the present invention to 0.1 to 250 dPa · s with lactic acid ester. More effectively, it may be 0.5 to 50 dPa · s. In addition, since dilution efficiency is poor when only lactic acid esters are diluted, it is possible to easily adjust the coating film thickness and the composition while suppressing the repellency phenomenon by using another general-purpose solvent in combination.

  Therefore, normally, the repellency phenomenon cannot be suppressed unless the coating thickness of the curable resin composition 13 is increased, but according to this embodiment, the film thickness is adjusted by adjusting the viscosity of the composition with lactic acid ester. Even if it is made thinner, the repellency phenomenon is suppressed, and the film thickness around the minute holes can be kept uniform.

  In addition, when lactate is used as a diluent, the dryness is good and the touch-drying property of the dried coating film can be improved, and lactate is not used in image formation after exposure. It was unexpectedly obtained that a narrower minimum residual line could be formed compared to the conventional one. Although the details are unknown, it is conceivable that the photoreactivity at the bottom of the solder resist is improved because the amount of residual solvent when the curable resin composition is dried is reduced.

The lactic acid esters used in this way include not only lactic acid esters derived from fossil fuels but also lactic acid esters produced by fermentation from starch such as corn. A fossil fuel-derived lactic acid ester (mixture of D-form and L-form which are optical isomers) and a fermented lactic ester derived from a natural product (L-form) have almost the same effect. Since L-form lactic acid ester (L-lactic acid ester) has natural product-derived carbon, it can reduce the influence on the environment and the human body from the environmental aspect of fossil fuel depletion and CO ² emission reduction. .

  Specific examples of the lactic acid ester in the present embodiment include methyl lactate, ethyl lactate, n-propyl lactate, isopropyl lactate, n-butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, n-hexyl lactate, and cyclohexyl lactate. Benzyl lactate and the like, preferably methyl lactate and ethyl lactate. These lactic acid ester compounds may be used alone or as a mixture of two or more, and either L-form or D-form may be used.

  Furthermore, the curable resin composition of this embodiment can contain various components such as a thermosetting component and a photosensitive component in addition to the lactic acid ester. As long as it can be used suitably for a printed wiring board, such as insulation and heat resistance, it is not limited to a specific structural component, and can be appropriately selected.

  Basically, various embodiments including a thermosetting component, a photosensitive component, or both components are conceivable. In the case of an alkali development type solder resist, in addition to a lactic acid ester and a carboxyl group-containing resin, a photopolymerization initiator, a thermosetting component such as a compound having two or more ethylenically unsaturated groups in the molecule and an epoxy compound, Furthermore, a thermosetting catalyst, a filler, an organic solvent, etc. can be contained as needed. Since the curable resin composition of the present invention can be derived from natural products, the burden on the environment is small.

  And the hardened | cured material of a desired characteristic and a printed wiring board can be obtained by selecting suitably the kind of said each component, and using it as a curable resin composition which optimized the mixture ratio.

  In the present embodiment, as the carboxyl group-containing resin, various resin compounds having a carboxyl group in the molecule can be used, and alkali developability can be imparted. As such a carboxyl group-containing resin, a carboxyl group-containing photosensitive resin having an ethylenically unsaturated double bond in the molecule is more preferable from the viewpoint of photocurability and development resistance. The unsaturated double bond is preferably derived from acrylic acid, methacrylic acid or derivatives thereof.

  As specific examples of the carboxyl group-containing resin, compounds listed below are preferable. The term “(meth) acrylate” is a general term for acrylate, methacrylate, and a mixture thereof, and the same applies to other similar expressions.

  (1) A carboxyl group-containing resin obtained by copolymerization of (meth) acrylic acid and an unsaturated group-containing material.

  (2) A carboxylic acid-containing urethane resin by a polyaddition reaction of a diisocyanate, a carboxyl group-containing dialcohol compound, and a diol compound.

  (3) Photosensitive carboxylic acid-containing urethane resin by polyaddition reaction of diisocyanate and bifunctional epoxy (meth) acrylate or its partial acid anhydride modified product, carboxyl group-containing dialcohol compound and diol compound.

  (4) A terminal (meth) acrylated carboxylic acid-containing urethane resin added with a compound having one hydroxyl group and one or more (meth) acrylic groups in the molecule during the synthesis of the resin described in (2) or (3) above. .

  (5) A terminal (meth) acrylated carboxylic acid-containing urethane is added by adding a compound having one isocyanate group and one or more (meth) acryl groups in the molecule during the synthesis of the resin described in (2) or (3) above. resin.

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

  (7) Photosensitivity in which (meth) acrylic acid is reacted with a polyfunctional epoxy resin obtained by epoxidizing the hydroxyl group of a bifunctional (solid) epoxy resin with epichlorohydrin, and a dibasic acid anhydride is added to the resulting hydroxyl group. Functional carboxyl group-containing resin.

  (8) A carboxylic acid-containing polyester resin obtained by reacting a difunctional oxetane resin with a dicarboxylic acid and adding a dibasic acid anhydride to the resulting primary hydroxyl group.

  (9) A photosensitive carboxyl group-containing resin obtained by further adding a compound having one epoxy group and one or more (meth) acryl groups in one molecule to the resin described above.

  Lactic acid esters are also used for the synthesis of such carboxyl group-containing resins.

  By containing these carboxyl group-containing resins, the backbone polymer has a number of free carboxyl groups in the side chain, so that development with a dilute aqueous alkali solution is possible.

Moreover, it is preferable that the acid value of carboxyl group-containing resin is 40-200 mgKOH / g. When the acid value of the carboxyl group-containing resin is less than 40 mgKOH / g, alkali development becomes difficult. On the other hand, when the acid value exceeds 200 mgKOH / g, dissolution of the exposed area by the developer proceeds and the line becomes thinner than necessary. Depending on the case, the exposed portion and the unexposed portion may be dissolved and separated by the developer without distinction, and it becomes difficult to draw a normal resist pattern. More preferably, it is 45-120 mgKOH / g.

  Moreover, although the weight average molecular weight of carboxyl group-containing resin changes with resin frame | skeleton, what is generally in the range of 2,000-150,000, Furthermore, 5,000-100,000 is preferable. When the weight average molecular weight is less than 2,000, the tack-free performance may be inferior, the moisture resistance of the coated film after exposure may be poor, and the film may be reduced during development, and the resolution may be greatly inferior. On the other hand, when the weight average molecular weight exceeds 150,000, developability may be remarkably deteriorated, and storage stability may be inferior.

  The blending ratio of such a carboxyl group-containing resin is preferably 20 to 60% by mass in the entire composition. When the amount is less than the above range, the coating strength is lowered, which is not preferable. On the other hand, when the amount is more than the above range, the viscosity becomes high or the coating property is lowered. More preferably, it is 30-50 mass%.

  Such carboxyl-containing resins can be used alone or in admixture of two or more.

  In addition, as the photopolymerization initiator, one or more selected from the group consisting of an oxime ester photopolymerization initiator, an α-aminoacetophenone photopolymerization initiator, and an acylphosphine oxide photopolymerization initiator is used. Can be used.

  Specific examples of the oxime ester photopolymerization initiator include commercially available products such as CGI-325, Irgacure OXE01, and Irgacure OXE02 manufactured by Ciba Specialty Chemicals, Inc., and N-1919 manufactured by ADEKA. These oxime ester photopolymerization initiators can be used alone or in combination of two or more.

  Examples of α-aminoacetophenone photopolymerization initiators include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1, 2-benzyl-2-dimethylamino-1- (4-morpholino Phenyl) -butan-1-one, 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, N, N-dimethyl Examples include aminoacetophenone. Examples of commercially available products include Irgacure 907, Irgacure 369, and Irgacure 379 manufactured by Ciba Specialty Chemicals.

  Acylphosphine oxide photopolymerization initiators include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2 4,4-trimethyl-pentylphosphine oxide and the like. Examples of commercially available products include Lucilin TPO manufactured by BASF and Irgacure 819 manufactured by Ciba Specialty Chemicals.

  The blending ratio of such a photopolymerization initiator may be 0.01 to 30 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin described above. If it is less than 0.01 parts by mass, the photocurability on copper used for the printed wiring board is insufficient, and the coating film is peeled off or the coating film properties such as chemical resistance are deteriorated. . On the other hand, when it exceeds 30 parts by mass, light absorption on the surface of the solder resist coating film of the photopolymerization initiator becomes intense, and the deep curability tends to decrease. More preferably, it is 0.5-15 mass parts.

  In the case of the oxime ester photopolymerization initiator, the blending ratio is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin described above. More preferably, it is 0.01-5 mass parts.

  Furthermore, in the curable resin composition of the present embodiment, a photopolymerization initiator other than the above-described compounds, a photoinitiator assistant, and a sensitizer can be used. Examples include benzoin compounds, acetophenone compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, xanthone compounds, and tertiary amine compounds.

  Specific examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether.

  Specific examples of the acetophenone compound include acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, and the like.

  Specific examples of the anthraquinone compound include 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone and the like.

  Specific examples of the thioxanthone compound include 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone.

  Specific examples of the ketal compound include acetophenone dimethyl ketal and benzyl dimethyl ketal.

  Specific examples of the benzophenone compound include benzophenone, 4-benzoyldiphenyl sulfide, 4-benzoyl-4′-methyldiphenyl sulfide, 4-benzoyl-4′-ethyldiphenyl sulfide, 4-benzoyl-4′-propyl diphenyl sulfide. Etc.

  Specific examples of the tertiary amine compound include ethanolamine compounds and compounds having a dialkylaminobenzene structure, such as 4,4′-dimethylaminobenzophenone (Nisso Cure MABP manufactured by Nippon Soda Co., Ltd.), 4,4′-diethylaminobenzophenone ( Dialkylaminobenzophenone such as Hoabaya Chemical Co. EAB), dialkylamino group-containing coumarin such as 7- (diethylamino) -4-methyl-2H-1-benzopyran-2-one (7- (diethylamino) -4-methylcoumarin) Compound, ethyl 4-dimethylaminobenzoate (Kayacure EPA manufactured by Nippon Kayaku Co., Ltd.), ethyl 2-dimethylaminobenzoate (Quantacure DMB manufactured by International Bio-Synthetics), 4-dimethylaminobenzoic acid (n-butyl) Xyl) ethyl (Quantacure BEA, manufactured by International Bio-Synthetics), p-dimethylaminobenzoic acid isoamyl ethyl ester (Kayacure DMBI, manufactured by Nippon Kayaku Co., Ltd.), 2-ethylhexyl 4-dimethylaminobenzoic acid (Esol manufactured by Van Dyk) 507), 4,4'-diethylaminobenzophenone (EAB manufactured by Hodogaya Chemical Co., Ltd.) and the like.

  Of these compounds, thioxanthone compounds and tertiary amine compounds are particularly preferable. The inclusion of a thioxanthone compound is preferable from the viewpoint of deep curable properties, and among them, thioxanthone compounds such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone are preferable.

  The mixing ratio of such a thioxanthone compound is preferably 20 parts by mass or less with respect to 100 parts by mass of the carboxyl group-containing resin. When there are too many compounding ratios of a thioxanthone compound, thick film sclerosis | hardenability will fall and it will lead to the cost increase of a product. More preferably, it is 10 parts by mass or less.

  As the tertiary amine compound, a compound having a dialkylaminobenzene structure is preferable, and among them, a dialkylaminobenzophenone compound and a dialkylamino group-containing coumarin compound having a maximum absorption wavelength of 350 to 410 nm are particularly preferable. As the dialkylaminobenzophenone compound, 4,4'-diethylaminobenzophenone is preferable because of its low toxicity. The dialkylamino group-containing coumarin compound having a maximum absorption wavelength of 350 to 410 nm has a maximum absorption wavelength in the ultraviolet region, so that it is less colored and uses a colored pigment as well as a colorless and transparent photosensitive composition. A colored solder resist film reflecting the color can be provided. In particular, 7- (diethylamino) -4-methyl-2H-1-benzopyran-2-one is preferable because it exhibits an excellent sensitizing effect on laser light having a wavelength of 400 to 410 nm.

  The mixing ratio of such a tertiary amine compound is preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin. When the proportion of the tertiary amine compound is less than 0.1 parts by mass, a sufficient sensitizing effect tends not to be obtained. When the amount exceeds 20 parts by mass, light absorption on the surface of the dried solder resist coating film by the tertiary amine compound becomes intense, and the deep curability tends to decrease. More preferably, it is a ratio of 0.1 to 10 parts by mass.

  These photopolymerization initiators, photoinitiator assistants, and sensitizers can be used alone or in admixture of two or more.

  Moreover, the compound which has 2 or more ethylenically unsaturated groups in a molecule | numerator is photocured by active energy ray irradiation, and insolubilizes a carboxyl group-containing resin in alkaline aqueous solution, or helps insolubilization. Examples of such compounds include glycol diacrylates such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanurate, and the like. Polyhydric acrylates such as polyhydric alcohols or their ethylene oxide adducts or propylene oxide adducts; polyhydric acrylates such as phenoxy acrylate, bisphenol A diacrylate, and ethylene oxide adducts or propylene oxide adducts of these phenols Glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane trig Ethers, polyvalent acrylates of glycidyl ethers such as triglycidyl isocyanurate; and melamine acrylate, and / or the like each methacrylates corresponding to the acrylates.

  Further, an epoxy acrylate resin obtained by reacting acrylic acid with a polyfunctional epoxy resin such as a cresol novolac type epoxy resin, or a hydroxy acrylate such as pentaerythritol triacrylate and a diisocyanate such as isophorone diisocyanate on the hydroxyl group of the epoxy acrylate resin. Examples thereof include an epoxy urethane acrylate compound obtained by reacting a half urethane compound. Such an epoxy acrylate resin can improve photocurability without deteriorating the touch drying property.

  The blending ratio of the compound having two or more ethylenically unsaturated groups in the molecule is preferably 5 to 100 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin. When the blending ratio is less than 5 parts by mass, the photocurability is lowered, and pattern formation becomes difficult by alkali development after irradiation with active energy rays. On the other hand, when it exceeds 100 mass parts, the solubility with respect to alkaline aqueous solution will fall, and a coating film will become weak. More preferably, it is a ratio of 1 to 70 parts by mass.

  Moreover, thermosetting components, such as an epoxy compound, are used in order to provide heat resistance. Particularly preferred is a thermosetting component having two or more cyclic ether groups and / or cyclic thioether groups (hereinafter abbreviated as cyclic (thio) ether groups) in the molecule.

  Such a thermosetting component having two or more cyclic (thio) ether groups in the molecule is either one of the three-, four- or five-membered cyclic ether groups in the molecule, or the cyclic thioether group, or two kinds thereof. A compound having at least two epoxy groups in the molecule, that is, a polyfunctional epoxy compound, a compound having at least two oxetanyl groups in the molecule, that is, a polyfunctional compound. Examples include oxetane compounds, compounds having two or more thioether groups in the molecule, that is, episulfide resins.

  Specific examples of the polyfunctional epoxy compound include Epicoat 828, Epicoat 834, Epicoat 1001, Epicoat 1004, and Epicron 840, Epicron 850, Epicron 1050, and Epicron 2055 manufactured by Dainippon Ink & Chemicals, Inc. Etototo YD-011, YD-013, YD-127, YD-128 manufactured by Toto Kasei Co., Ltd., D.C. E. R. 317, D.E. E. R. 331, D.D. E. R. 661, D.E. E. R. 664, Ciba Specialty Chemicals' Araldide 6071, Araldide 6084, Araldide GY250, Araldide GY260, Sumitomo Chemical Industries Sumi-Epoxy ESA-011, ESA-014, ELA-115, ELA-128, Asahi Kasei Kogyo Co., Ltd. A. E. R. 330, A.I. E. R. 331, A.I. E. R. 661, A.I. E. R. Bisphenol A type epoxy resin such as 664 (all trade names); Epicoat YL903 manufactured by Japan Epoxy Resin, Epicron 152, Epicron 165 manufactured by Dainippon Ink & Chemicals, Epototo YDB-400, YDB- manufactured by Tohto Kasei Co., Ltd. 500, D.C. E. R. 542, Araldide 8011 manufactured by Ciba Specialty Chemicals, Sumi-epoxy ESB-400, ESB-700 manufactured by Sumitomo Chemical Co., Ltd., and A.D. E. R. 711, A.I. E. R. Brominated epoxy resins such as 714 (all trade names); Epicoat 152 and Epicoat 154 manufactured by Japan Epoxy Resin Co., Ltd., D.C. E. N. 431, D.D. E. N. 438, Epicron N-730, Epicron N-770, Epicron N-865, Etototo YDCN-701, YDCN-704 from Toto Kasei Co., Ltd., Araldide ECN1235 from Ciba Specialty Chemicals, Araldide ECN1273, Araldide ECN1299, Araldide XPY307, Nippon Kayaku Co., Ltd. EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306, Sumitomo Chemical Industries Sumi-epoxy ESCN-195X, ESCN- 220, manufactured by Asahi Kasei Corporation. E. R. Novolak type epoxy resins such as ECN-235, ECN-299, etc. (both trade names); Epicron 830 manufactured by Dainippon Ink & Chemicals, Epicoat 807 manufactured by Japan Epoxy Resin, Epototo YDF-170 manufactured by Toto Kasei Co., Ltd., YDF -175, YDF-2004, Araldide XPY306 manufactured by Ciba Specialty Chemicals (both are trade names), bisphenol F type epoxy resin; Etototo ST-2004, ST-2007, ST-3000 manufactured by Toto Kasei Hydrogenated bisphenol A type epoxy resin, such as Epicoat 604 manufactured by Japan Epoxy Resin Co., Ltd., Epotot YH-434 manufactured by Tohto Kasei Co., Ltd., Araldide MY720 manufactured by Ciba Specialty Chemicals Co., Ltd., Sumitomo Chemical Co., Ltd. Epoxy ELM Glycidylamine type epoxy resins such as 120 (both trade names); Hydantoin type epoxy resins such as Araldide CY-350 (trade name) manufactured by Ciba Specialty Chemicals; Celoxide 2021 manufactured by Daicel Chemical Industries, Ciba Specialty Alicyclic epoxy resins such as Araldide CY175 and CY179 manufactured by Chemicals (both are trade names); YL-933 manufactured by Japan Epoxy Resin Co., Ltd. E. N. , EPPN-501, EPPN-502, etc. (all trade names) trihydroxyphenylmethane type epoxy resin; Japan Epoxy Resin YL-6056, YX-4000, YL-6121 (all trade names), etc. Xylenol type or biphenol type epoxy resins or mixtures thereof; bisphenol S type such as EBPS-200 manufactured by Nippon Kayaku Co., Ltd., EPX-30 manufactured by Asahi Denka Kogyo Co., Ltd., EXA-1514 manufactured by Dainippon Ink & Chemicals, Inc. Epoxy resin; Bisphenol A novolak type epoxy resin such as Epicoat 157S (trade name) manufactured by Japan Epoxy Resin; Epicoat YL-931 manufactured by Japan Epoxy Resin, Araldide 163 manufactured by Ciba Specialty Chemicals, etc. Name) Tetrahu Nylolethane type epoxy resin; heterocyclic epoxy resin such as Araldide PT810 manufactured by Ciba Specialty Chemicals, TEPIC manufactured by Nissan Chemical Industries (all trade names); diglycidyl phthalate resin such as Bremer DGT manufactured by Nippon Oil &Fats; Tetraglycidylxylenoylethane resins such as ZX-1063 manufactured by Tohto Kasei Co., Ltd .; Naphthalenes such as ESN-190 and ESN-360 manufactured by Nippon Steel Chemical Co., Ltd., HP-4032, EXA-4750, and EXA-4700 manufactured by Dainippon Ink & Chemicals, Inc. Group-containing epoxy resin; Epoxy resin having a dicyclopentadiene skeleton such as HP-7200 and HP-7200H manufactured by Dainippon Ink &Chemicals; Glycidyl methacrylate copolymer epoxy such as CP-50S and CP-50M manufactured by Nippon Oil & Fats Co., Ltd. Resin; Copolymerized epoxy resin of rohexylmaleimide and glycidyl methacrylate; epoxy-modified polybutadiene rubber derivative (for example, PB-3600 manufactured by Daicel Chemical Industries), CTBN-modified epoxy resin (for example, YR-102, YR-450 manufactured by Tohto Kasei Co., Ltd.) ) Etc., but are not limited to these. These epoxy resins can be used alone or in combination of two or more. Among these, a novolac type epoxy resin, a heterocyclic epoxy resin, a bisphenol A type epoxy resin or a mixture thereof is particularly preferable.

  Polyfunctional oxetane compounds include bis [(3-methyl-3-oxetanylmethoxy) methyl] ether, bis [(3-ethyl-3-oxetanylmethoxy) methyl] ether, 1,4-bis [(3-methyl- 3-Oxetanylmethoxy) methyl] benzene, 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, (3-methyl-3-oxetanyl) methyl acrylate, (3-ethyl-3-oxetanyl) In addition to polyfunctional oxetanes such as methyl acrylate, (3-methyl-3-oxetanyl) methyl methacrylate, (3-ethyl-3-oxetanyl) methyl methacrylate and oligomers or copolymers thereof, oxetane alcohol and novolak resin, poly (P-hydroxystyrene), cardo-type bisphenol Le ethers, calixarenes, calix resorcin arenes, or the like ethers of a resin having a hydroxyl group such as silsesquioxane and the like. In addition, a copolymer of an unsaturated monomer having an oxetane ring and an alkyl (meth) acrylate is also included.

  Examples of the compound having two or more cyclic thioether groups in the molecule include bisphenol A type episulfide resin YL7000 manufactured by Japan Epoxy Resin Co., Ltd. Moreover, episulfide resin etc. which replaced the oxygen atom of the epoxy group of the novolak-type epoxy resin with the sulfur atom using the same synthesis method can be used.

  The blending ratio of the thermosetting component having two or more cyclic (thio) ether groups in the molecule is 0.6 to 2.5 equivalents with respect to 1 equivalent of the carboxyl group of the carboxyl group-containing resin. It is preferable. When the blending ratio of the thermosetting component having two or more cyclic (thio) ether groups in the molecule is less than 0.6, a carboxyl group remains in the solder resist film, and heat resistance, alkali resistance, electrical insulation, etc. Will fall. On the other hand, when the amount exceeds 2.5 equivalents, the low molecular weight cyclic (thio) ether group remains in the dry coating film, thereby reducing the strength of the coating film. More preferably, it is 0.8-2.0 equivalent.

  Moreover, it is preferable to contain a thermosetting catalyst together, when using the thermosetting component which has a 2 or more cyclic (thio) ether group in the molecule | numerator mentioned above. Specific examples of such a thermosetting catalyst include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, and 1-cyanoethyl-2. -Imidazole derivatives such as phenylimidazole, 1- (2-cyanoethyl) -2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy- Amine compounds such as N, N-dimethylbenzylamine and 4-methyl-N, N-dimethylbenzylamine, hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; phosphorus compounds such as triphenylphosphine, and the like are also commercially available. things and For example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ (all trade names of imidazole compounds) manufactured by Shikoku Kasei Kogyo Co., Ltd., U-CAT3503N, U-CAT3502T (all dimethylamine manufactured by San Apro) Product names of blocked isocyanate compounds), DBU, DBN, U-CATSA102, U-CAT5002 (both bicyclic amidine compounds and salts thereof), and the like.

  However, it is not particularly limited to these, and any thermosetting catalyst for an epoxy resin or an oxetane compound, or one that promotes the reaction between an epoxy group and / or an oxetanyl group and a carboxyl group may be used. And it can use individually or in mixture of 2 or more types.

  Further, guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-4,6-diamino-S-, which are compounds that also function as an adhesion-imparting agent. Use of S-triazine derivatives such as triazine, 2-vinyl-4,6-diamino-S-triazine / isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxyethyl-S-triazine / isocyanuric acid adduct You can also. These are preferably used in combination with the above-described thermosetting catalyst.

  The mixing ratio of these thermosetting catalysts is sufficient in the usual quantitative ratio, for example, with respect to 100 parts by mass of the carboxyl group-containing resin or thermosetting component having two or more cyclic (thio) ether groups in the molecule. 0.1 to 20 parts by mass is preferable. More preferably, it is 0.5-15.0 mass parts.

  The filler is used as necessary to increase the physical strength of the coating film. As such a filler, an inorganic or organic filler can be used, and barium sulfate, spherical silica and talc are particularly preferably used. Moreover, when using for an interlayer insulation layer like a prepreg, an insulating sheet, and copper foil with resin, a glass cloth, an inorganic, and an organic fiber nonwoven fabric can be used. Furthermore, in order to obtain a white appearance and flame retardancy, metal hydroxides such as titanium oxide, metal oxide, and aluminum hydroxide can be used as extender pigment fillers.

  The blending ratio of the filler is preferably 300 parts by mass or less with respect to 100 parts by mass of the carboxyl group-containing resin. When the blending ratio of the filler exceeds 300 parts by mass, the viscosity of the photocurable resin composition is increased and the printability is lowered, or the cured product is brittle. More preferably, it is 0.1-300 mass parts, Most preferably, it is 0.1-150 mass parts.

  Here, the organic solvent is an organic solvent other than a lactic acid ester, and is used for synthesis of a carboxyl group-containing resin, adjustment of the composition, or adjustment of viscosity for application to a substrate or a carrier film. Examples of such an organic solvent include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents, and the like. Specifically, ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether , Glycol ethers such as dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, Esters such as propylene glycol butyl ether acetate; ethanol, propano Le, ethylene glycol, alcohols such as propylene glycol; octane, aliphatic hydrocarbons such as decane; petroleum ether, and the like petroleum naphtha, hydrogenated petroleum naphtha, petroleum solvents such as solvent naphtha. Such organic solvents are used alone or as a mixture of two or more.

  Furthermore, if necessary, any known and commonly used colorants (pigments, dyes, pigments, etc.) such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, naphthalene black, etc. ) Can be used.

  Examples of these colorants are given below.

[Blue colorant]
Blue colorants include phthalocyanine and anthraquinone, and pigments are compounds classified as Pigment. Specifically, the following color index (CI; issued by The Society of Dyers and Colorists) number Can be mentioned.

Pigment Blue 15, Pigment Blue 15: 1, Pigment Blue 15: 2, Pigment Blue 15: 3, Pigment Blue 15: 4, Pigment Blue 15: 6, Pigment Blue 16, Pigment Blue 60,
As a dye system
Solvent Blue 35, Solvent Blue 45, Solvent Blue 63, Solvent Blue 68, Solvent Blue 70, Solvent Blue 83, Solvent Blue 87, Solvent Blue 94, Solvent Blue 97, Solvent Blue 101, Solvent Blue 104, Solvent Blue 122, Solvent Blue 136, Solvent Blue 67, Solvent Blue 70, etc. can be used. Besides these, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

[Green colorant]
Similarly, green colorants include phthalocyanine, anthraquinone, and perylene.
Pigment Green 7, Pigment Green 36, Solvent Green 3, Solvent Green 5, Solvent Green 20, Solvent Green 28
Etc. In addition to these, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

[Yellow colorant]
Examples of yellow colorants include monoazo, disazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone, and specific examples include the following.

(Anthraquinone)
Solvent Yellow 163, Pigment Yellow 24, Pigment Yellow 108, Pigment Yellow 193, Pigment Yellow 147, Pigment Yellow 199, Pigment Yellow 202
(Isoindolinone series)
Pigment Yellow 110, Pigment Yellow 109, Pigment Yellow 139, Pigment Yellow 179, Pigment Yellow 185
(Condensed azo)
Pigment Yellow 93, Pigment Yellow 94, Pigment Yellow 95, Pigment Yellow 128
, Pigment Yellow 155, Pigment Yellow 166, Pigment Yellow 180
(Benz imidazolone)
Pigment Yellow 120, Pigment Yellow 151, Pigment Yellow 154, Pigment Yellow 156, Pigment Yellow 175, Pigment Yellow 181
(Monoazo)
PigmentYellow1,2,3,4,5,6,9,10,12,61,62,62: 1,65,73,74,75,97,100,104,105,111,116,167,168,169,182,183,
(Disazo)
PigmentYellow12,13,14,16,17,55,63,81,83,87,126,127,152,170,172,174,176,188,198
[Red colorant]
Examples of red colorants include monoazo, disazo, azo lake, benzimidazolone, perylene, diketopyrrolopyrrole, condensed azo, anthraquinone, and quinacridone. Specific examples include the following: It is done.

(Monoazo)
PigmentRed1,2,3,4,5,6,8,9,12,14,15,16,17,21,22,23,31,32,112,114,146,147,151,170,184,187,188,193,210,245,253,258,266,267,268,269,
(Disazo series)
Pigment Red 37,38,41
(Monoazo lake)
PigmentRed48: 1,48: 2,48: 3,48: 4,49: 1,49: 2,50: 1,52: 1,52: 2,53: 1,53: 2,57: 1,58: 4,63: 1,63: 2,64: 1,68
(Benz imidazolone)
Pigment Red 171, Pigment Red 175, Pigment Red 176, Pigment Red 185, Pigment Red 208
(Perylene)
Solvent Red 135, Solvent Red 179, Pigment Red 123, Pigment Red 149, Pigment Red 166, Pigment Red 178, Pigment Red 179, Pigment Red 190, Pigment Red 194, Pigment Red 224
(Diketopyrrolopyrrole)
Pigment Red 254, Pigment Red 255, Pigment Red 264, Pigment Red 270, Pigment Red 272
(Condensed azo)
Pigment Red 220, Pigment Red 144, Pigment Red 166, Pigment Red 214, Pigment Red 220, Pigment Red 221 and Pigment Red 242
(Anthraquinone)
Pigment Red 168, Pigment Red 177, Pigment Red 216, Solvent Red 149, Solvent Red 150, Solvent Red 52, Solvent Red 207
(Quinacridone series)
Pigment Red 122, Pigment Red 202, Pigment Red 206, Pigment Red 207, Pigment Red 209
Other colorants such as purple, orange, brown, and black may be added for the purpose of adjusting the color tone. Specifically, Pigment Violet 19, 23, 29, 32, 36, 38, 42, Solvent Violet 13, 36, CI Pigment Orange 1, CI Pigment Orange 5, CI Pigment Orange 13, CI Pigment Orange 14, CI Pigment Orange 16, CI Pigment Orange 17, CI Pigment Orange 24, CI Pigment Orange 34, CI Pigment Orange 36, CI Pigment Orange 38, CI Pigment Orange 40, CI Pigment Orange 43, CI Pigment Orange 46, CI Pigment Orange 49, CI Pigment Orange 51, CI Pigment Orange 61, CI Pigment Orange 63, CI Pigment Orange 64, CI Pigment Orange 71, CI Pigment Orange 73, CI Pigment Brown 23, CI Pigment Brown 25; CI Pigment Black 1, CI Pigment Black 7, etc. It is below.

  Other known thermal polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, pyrogallol, phenothiazine, thickeners such as fine silica, organic bentonite, montmorillonite, silicones, fluorines, polymers, etc. Additives such as an antifoaming agent and / or leveling agent, an adhesion-imparting agent such as imidazole, thiazole, and triazole, and a silane coupling agent can be blended.

  Among such curable resin compositions, a photocurable composition containing a photosensitive component is applied on a substrate and photocured to form a cured product. Photocuring can be cured by an ultraviolet exposure device or a laser light source, particularly laser light having a wavelength of 350 to 410 nm. And the thermosetting resin composition and photocuring thermosetting composition containing a thermosetting component become a hardened | cured material by thermosetting by heating. By using the substrate as a circuit-formed substrate, a printed circuit board is formed in the same manner.

  Specifically, a cured product and a printed wiring board are formed as follows. For example, a curable resin composition adjusted to a viscosity suitable for the coating method with a lactic acid ester and other organic solvents is applied to a substrate including a circuit-formed substrate by a dip coating method, a flow coating method, a roll coating method. It is applied by a bar coater method, a spray coating method, a screen printing method, a curtain coating method or the like.

  Here, paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, fluorine / polyethylene / PPO / cyanate ester, etc. are used as the base material. All grades (FR-4, etc.) of copper-clad laminates, other polyimide films, PET films, glass substrates, ceramic substrates, wafer plates, etc. are used. Can do.

  And the tack-free coating film is formed by carrying out the volatile drying (temporary drying) of the organic solvent contained in a composition at the temperature of about 60-100 degreeC. Alternatively, the composition may be applied onto a carrier film, dried, and wound up as a film and pasted onto a substrate.

  Thereafter, the contact pattern (or non-contact pattern) is selectively exposed through an active energy ray through a photomask on which a pattern has been formed or directly exposed by a laser direct exposure machine, and unexposed areas that have not been cured by light irradiation are diluted. A pattern is formed by developing with an alkaline aqueous solution (for example, 0.3 to 3% sodium carbonate aqueous solution).

  Here, as an exposure device, a laser direct drawing device (laser direct imaging device), an exposure device equipped with a metal halide lamp, an exposure device equipped with a (super) high-pressure mercury lamp, an exposure device equipped with a mercury short arc lamp, or A direct drawing apparatus using an ultraviolet lamp such as a (super) high pressure mercury lamp can be used. When direct exposure is performed with a drawing apparatus, either a gas laser or a solid laser may be used as long as laser light having a maximum wavelength in the range of 350 to 410 nm is used. As the direct drawing apparatus, for example, those manufactured by Nippon Orbotech, ORC, etc. can be used, and any apparatus may be used as long as it oscillates laser light having a maximum wavelength of 350 to 410 nm. .

  As a developing method, a dipping method, a shower method, a spray method, a brush method, or the like can be used. As the developer, an alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines or the like can be used.

  Volatile drying is performed using a method 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, and a counter current contact with hot air in the dryer It can carry out using the system sprayed on a support body.

  Furthermore, in the case of a composition containing a thermosetting component, for example, by heating to a temperature of about 140 to 180 ° C. and thermosetting, the carboxyl group of the carboxyl group-containing resin and two or more in the molecule A thermosetting component having a cyclic ether group and / or a cyclic thioether group reacts to form a cured coating film excellent in various properties such as heat resistance, chemical resistance, moisture absorption resistance, adhesion, and electrical characteristics. Can do.

  Even if it does not contain a thermosetting component, the ethylenically unsaturated bond remaining in an unreacted state at the time of exposure undergoes thermal radical polymerization even when it does not contain a thermosetting component, thereby improving the coating film properties. Thus, heat treatment (thermosetting) may be performed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to the following Example. In the examples, parts and% are based on mass unless otherwise specified.

[Synthesis of Curable Resin Composition]
A 2 liter separable flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen introduction tube was added to a cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., EOCN-104S, softening point 92 ° C., epoxy equivalent 220). ) 660 g, carbitol acetate 421.3 g, and solvent naphtha 180.6 g were introduced, heated and stirred at 90 ° C., and dissolved.

  Next, it is once cooled to 60 ° C., 216 g of acrylic acid, 4.0 g of triphenylphosphine and 1.3 g of methylhydroquinone are added and reacted at 100 ° C. for 12 hours, and a reaction product having an acid value of 0.2 mgKOH / g. Got. This was charged with 241.7 g of tetrahydrophthalic anhydride, heated to 90 ° C. and reacted for 6 hours.

  Thus, a solution (B-1 varnish) of a carboxyl group-containing resin having an acid value of 50 mgKOH / g, a double bond equivalent (g weight of resin per mole of unsaturated groups) of 400, and a weight average molecular weight of 7,000 was obtained. Obtained.

  Using the resulting B-1 varnish, together with the components of the formulation examples shown below, premixed with a stirrer using a diluting solvent (lactic acid ester and organic solvent) at a blending ratio as shown in Table 1, and then 3 It knead | mixed with this roll mill and prepared the photosensitive resin composition for soldering resists.

(Formulation example)
Varnish 154 parts (solid content 100 parts)
Irg907 (Ciba Specialty Chemicals) 12 parts DETX (Nippon Kayaku) 0.5 parts dipentaerythritol hexaacrylate (DPHA / Nippon Kayaku) 20 parts phenol novolac epoxy resin (Dow Chemical) DEN-431) 15 parts bixylenol type epoxy resin (YX-4000 manufactured by Japan Epoxy Resin Co., Ltd.)
25 parts dicyandiamide 0.3 parts melamine 5 parts barium sulfate (barium sulfate B30 manufactured by Sakai Chemical Co., Ltd.) 100 parts Pigment 1 CI Pigment Blue 15: 3 0.3 part Pigment 2 CI Pigment Yellow 147 0.8 part 3 parts foam

* 1: Methyl lactate (2-hydroxymethylpropanoic acid)
* 2: L-methyl lactate (2-hydroxymethylpropanoic acid) fermented methyl lactate manufactured by Musashino Chemical Research Co., Ltd. (L-form content 99.6%)
* 3: Ethyl lactate (2-hydroxyethylpropanoic acid)
* 4: PM (propylene glycol monomethyl ether)
* 5: PMA (propylene glycol monomethyl ether acetate)
In addition, the addition amount of the dilution solvent computed the dilution rate at the time of IWATA CUP 30 second from the dilution viscosity curve shown in FIG. In addition,
Dilution rate (%) = total weight of ink / 100
Time (seconds) = ink drop time by IWATA CUP Ink temperature = 21 ° C ± 2 ° C
It was.

  Here, it was 15 micrometers or less when the dispersion degree of the obtained photosensitive resin composition was evaluated by the particle size measurement by the grindometer by Eriksen.

[Performance evaluation]
<Evaluation of viscosity>
The rotation speed of 5 rpm measured at 25 ° C. using the E-type rotational viscometer for the photocurable thermosetting resin compositions of the examples and comparative examples was taken as the viscosity.

<Evaluation of optimal exposure>
The photocurable thermosetting resin composition of each Example and Comparative Example was a circuit pattern substrate having a copper thickness of 50 μm, buffed, washed with water, dried and then dried by spray coating or screen printing, and the film thickness was 25 μm. The whole surface is coated, dried in a hot air circulation drying oven at 80 ° C. for 30 minutes, and allowed to cool to room temperature. After standing to cool, exposure was performed through a step tablet (Kodak No. 2) using an exposure apparatus (HMW680-GW20) manufactured by ORC, and development (30 ° C., 0.2 MPa, 1 mass% sodium carbonate aqueous solution) was performed in 60 seconds. When the pattern of the remaining step tablet was 7 steps, the optimum exposure amount was set.

[Characteristic evaluation]
<Color of coating film>
The color of the hardened | cured material of the alkali image development type solder resist of each Example and a comparative example was judged visually.

<Finger dryness>
The composition of each Example and Comparative Example was applied on the entire surface of a patterned copper foil substrate by spray coating or screen printing so that the film thickness was 25 μm after drying, and was heated in a hot air circulation drying oven at 60 ° C. for 30 minutes. Dry and allow to cool to room temperature. A negative film made of PET was applied to this substrate, and the film was pressure-bonded under reduced pressure for 1 minute with an exposure apparatus (HMW680-GW20) manufactured by ORC, and then the state of film sticking when the negative film was peeled off was evaluated according to the following criteria. .

○: The film peels without resistance.

(Triangle | delta): Although a film peels, a trace is attached to the coating film.

X: There is resistance when the film is peeled off, and the coating film has a clear mark.

<Cavity filling (for minute holes)>
The composition of each Example and Comparative Example was applied to the entire surface of the substrate having fine holes adjusted to φ100 μm and depth of 50 μm after copper plating so that the film thickness was 25 μm after drying by spray coating or screen printing, and 80 ° C. Dry in a hot air circulating drying oven for 30 minutes and allow to cool to room temperature. After standing to cool, the number of solder resists on the hole was visually counted and evaluated according to the following criteria.

Defect rate (%) = number of repellency / total number of holes 1700 holes ○: 3% or less Δ: 4% or more and 10% or less ×: 10% or more <Deep part curability>
A circuit pattern substrate having a line / space of 300/300 μm and a copper thickness of 50 μm was subjected to buffing, washing with water, drying, and then spray coating or screen printing, and then the film thickness was 25 μm. Then, the entire surface is coated, dried in a hot air circulating drying oven at 80 ° C. for 30 minutes, and allowed to cool to room temperature. After cooling, exposure was performed using an exposure apparatus (HMW680-GW20) manufactured by ORC. As the exposure pattern, a pattern for drawing a 20/30/40/50/60/70/80/90/100 μm line in the space portion was used. The exposure amount was the exposure amount obtained by the optimum exposure amount evaluation. After the exposure, development was performed with a 1% by mass aqueous sodium carbonate solution at 30 ° C. to draw a pattern, and a cured coating film was obtained by heat curing at 150 ° C. for 60 minutes.

  It counted using the optical microscope which adjusted the minimum residual line of the cured coating film of the obtained photocurable thermosetting resin composition to 200 time. Moreover, after cutting the center part of the line and performing mirror finish, the upper diameter, lower diameter, and film thickness of the minimum remaining line of the cured coating film were measured using an optical microscope adjusted to 1000 times. The evaluation criteria were such that the deeper part curability was better as the minimum remaining line was smaller and the lower diameter was closer to the design value.

The results are also shown in Table 1.

  As described above, it can be seen that the photosensitive resin composition for a solder resist of the example is a composition excellent in dryness to touch, filling in a minute hole and deep part curability.

  Thus, according to one embodiment of the present invention, it is possible to obtain a curable resin composition that is excellent in dryness to the touch, and further excellent in hole filling and deep part curability for minute holes. In particular, it is possible to provide a photocurable thermosetting resin composition suitable for use as a solder resist application, a cured product thereof, and a printed wiring board patterned using the same.

  In addition, this invention is not limited to embodiment mentioned above. Various other modifications can be made without departing from the scope of the invention.

The figure which shows a repelling phenomenon. The figure which shows a repelling phenomenon. The figure which shows the conventional application | coating state. The figure which shows the conventional dry state. The figure which shows the application | coating state in 1 aspect of this invention. The figure which shows the dry condition in 1 aspect of this invention. The figure which shows the dilution viscosity curve in 1 aspect of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Base material 12 ... Copper circuit 12a ... Minute hole 13 ... Curable resin composition

Claims (7)

A curable resin composition used for a printed wiring board in which minute holes are formed on the surface layer of a substrate,
Including a lactic acid ester, a carboxyl group-containing resin, and a photopolymerization initiator,
The carboxyl group-containing resin,
The bifunctional or polyfunctional epoxy resins by reacting (meth) acrylic acid, the curable resin characterized in that it is a photosensitive carboxyl resin obtained by adding a dibasic acid anhydride to a hydroxyl group present on the side chain composition object.   The curable resin composition according to claim 1, further comprising a colorant.   The curable resin composition according to claim 1, wherein the lactic acid ester is a natural product-derived L-lactic acid ester.   Viscosity is 0.1-250 dPa * s, The curable resin composition of any one of Claims 1-3 characterized by the above-mentioned.   The curable resin composition according to any one of claims 1 to 4, wherein the curable resin composition is a solder resist that covers a printed wiring board in which minute holes are formed in a surface layer of the substrate.   The curable resin composition according to any one of claims 1 to 5 is applied on a substrate, dried to form a dried coating film, and the dried coating film is cured. Characterized cured product.   A dry coating formed by applying and drying the curable resin composition according to any one of claims 1 to 5 on a substrate of a printed wiring board in which minute holes are formed in a surface layer of the substrate. A printed wiring board comprising a pattern formed by exposing, developing, and curing a film.

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