Solder resist composition and printed circuit board having cured product thereof

Abstract

The invention provides a solder resist composition used for filling a through hole of a printed circuit board and the printed circuit board with a cured product of the solder resist composition. The solder resist composition is characterized by containing (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a compound containing an ethylenically unsaturated group and an epoxy group, (D) an inorganic filler and (E) a thermosetting resin.

Description

[0001] This application is a divisional application of an application with an application date of July 7, 2020, application number 202010648326.0, and invention name of solder resist composition and printed circuit board having a cured product thereof. Technical Field

[0002] The present invention relates to a solder resist suitable for filling through holes of printed circuit boards, a photocurable resin composition having few voids and cracks after curing and excellent cavitation resistance, a cured product thereof, and a printed circuit board formed using the same. Background Art

[0003] At present, a multilayer printed circuit board formed by alternately laminating interlayer resin insulating layers and conductive circuit layers on a printed circuit substrate after filling a resin filler into a through hole provided in the printed circuit substrate and curing to make the surface smooth has been developed, or a multilayer printed circuit board in which a solder resist film for protecting the circuit is directly formed on a substrate filled with a resin filler in a through hole, etc. (Patent Document 1). In particular, recently, in order to reduce the manufacturing cost of printed circuit boards, the filling of through holes and the protection of circuits are performed using the same solder resist composition.

[0004] When the conventional alkali-developable photoresist is used for through-hole filling, the flame retardant composition in the through-hole is not sufficiently photocurable, which easily causes expansion and peeling (hereinafter referred to as "cavitation") during solder leveling. In addition, the uncured solder resist composition may flow out of the through-hole in the subsequent process, or voids or cracks may occur in the solder resist after the hole is filled.

[0005] Patent Document 1: WO2002 / 044272 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] An object of the present invention is to provide an alkali-developable photocurable resin composition which has few voids and cracks after curing, is excellent in cavitation resistance, and is suitable for a solder resist for through-hole filling of a printed wiring board, a cured product thereof, and a printed wiring board formed using the same.

[0008] Solutions for solving problems

[0009] The present inventors have conducted intensive studies to solve the above-mentioned problems and have found that a photocurable resin composition containing (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a compound containing an ethylenically unsaturated group and an epoxy group, (D) an inorganic filler and (E) a thermosetting resin has few voids and cracks after curing and has good cavitation resistance, and is suitable for through-hole filling of printed circuit boards, thereby completing the present invention.

[0010] That is, the present invention provides the following technical solutions.

[0011] 1. A solder resist composition for use in filling through holes of printed circuit boards, characterized in that it contains (A) a carboxyl-containing resin, (B) a photopolymerization initiator, (C) a compound containing an ethylenically unsaturated group and an epoxy group, (D) an inorganic filler and (E) a thermosetting resin.

[0012] 2. The solder resist composition for through-hole filling of a printed circuit board according to 1, characterized in that it contains, as (B) a photopolymerization initiator, a (B1) photopolymerization initiator having an absorbance of 1.0 or more at a wavelength of 450 nm in a 0.1 wt % 1-methyl-2-pyrrolidone solution.

[0013] 3. The solder resist composition for filling through-holes of printed wiring boards according to 2, wherein the content of the photopolymerization initiator (B1) is 0.05 to 1.0 part by weight relative to 100 parts by weight of the carboxyl group-containing resin (A).

[0014] 4. The solder resist composition for filling through-holes of printed wiring boards according to 1, wherein the content of the inorganic filler (D) is 60 to 200 parts by weight relative to 100 parts by weight of the carboxyl group-containing resin (A).

[0015] 5. The solder resist composition for filling through-holes of printed wiring boards according to 1, wherein the content of the thermosetting resin (E) is 10 to 70 parts by weight relative to 100 parts by weight of the carboxyl group-containing resin (A).

[0016] 6. The solder resist composition for filling through holes of printed wiring boards according to item 1, further comprising (F) a reactive diluent having no epoxy group and having an ethylenically unsaturated group.

[0017] 7. The solder resist composition for through-hole filling of a printed circuit board according to 6, wherein the content of the reactive diluent (F) having no epoxy group and having an ethylenically unsaturated group is 1 to 60 parts by weight relative to 100 parts by weight of the carboxyl group-containing resin (A).

[0018] 8. The solder resist composition for through-hole filling of a printed circuit board according to 1, wherein the content of the compound (C) containing an ethylenically unsaturated group and an epoxy group is 1 to 60 parts by weight relative to 100 parts by weight of the carboxyl group-containing resin (A).

[0019] 9. The solder resist composition for through-hole filling of a printed circuit board according to 1, wherein the (C) compound containing an ethylenically unsaturated group and an epoxy group is a multifunctional compound containing an ethylenically unsaturated group and an epoxy group.

[0020] 10. The solder resist composition for filling through holes of printed wiring boards according to any one of 1 to 9, wherein the (C) compound containing an ethylenically unsaturated group and an epoxy group has an isocyanurate skeleton.

[0021] 11. The solder resist composition for filling through holes of printed circuit boards according to 10, wherein the (E) thermosetting resin contains (E1) a liquid epoxy resin.

[0022] 12. A printed wiring board comprising a cured product of the solder resist composition for through-hole filling of a printed wiring board according to any one of 1 to 11.

[0023] Effects of the Invention

[0024] The present invention provides a photocurable resin composition having few voids and cracks after curing and excellent cavitation resistance, and a printed circuit board having the cured product thereof. The photocurable resin composition of the present invention is most suitable as a solder resist for through-hole filling of a printed circuit board.

[0025] The alkali-developable photoresist compositions of the past are prone to voids or cracks, and have low cavitation resistance. It is believed that the reason is that the previous compositions are poorly cured at the center of the through hole, that is, the compound having the ethylenically unsaturated group remains unreacted. As a result, defects such as voids occur.

[0026] The present invention uses a compound containing an ethylenically unsaturated group and an epoxy group in one molecule, so that even if the ethylenically unsaturated group in some molecules does not react when irradiated with active energy rays, the epoxy groups in these molecules can react with the carboxyl groups of the carboxyl group-containing resin (A). As a result, poor curing of the compound containing an ethylenically unsaturated group and an epoxy group does not occur, the occurrence of voids and cracks can be suppressed, and cavitation resistance can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the device used for determining the liquid state of the epoxy resin of the present invention. DETAILED DESCRIPTION

[0028] That is, the solder resist composition for through-hole filling of a printed circuit board of the present invention is characterized by containing (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a compound containing an ethylenically unsaturated group and an epoxy group, (D) an inorganic filler and (E) a thermosetting resin.

[0029] The (A) carboxyl group-containing resin used in the present invention can be obtained, for example, by reacting a reaction product of (a) a polyfunctional epoxy compound and (b) a monocarboxylic acid containing an unsaturated group with (c) a polybasic acid anhydride.

[0030] (a) A polyfunctional epoxy compound and (b) A monocarboxylic acid containing an unsaturated group are mixed in a ratio of 0.9 to 1.2 mol of (b) a monocarboxylic acid containing an unsaturated group to 1 mol of epoxy groups contained in the polyfunctional epoxy compound (a), and reacted in the presence or absence of an organic solvent in the presence of a polymerization inhibitor such as hydroquinone or oxygen and, if necessary, a tertiary amine such as triethylamine, a quaternary ammonium salt such as triethylbenzylammonium chloride, an imidazole compound such as 2-ethyl-4-methylimidazole, a phosphorus compound such as triphenylphosphine, etc., usually at about 80 to 140°C to obtain an epoxy acrylate compound.

[0031] As the polyfunctional epoxy compound, known conventional epoxy resin can be used. As representative example, for example, known conventional epoxy compounds such as bisphenol A type, hydrogenated bisphenol A type, bisphenol F type, bisphenol S type, phenol novolac type, cresol novolac type, bisphenol A novolac type, biphenol type, dimethylphenol type, N-glycidol type, etc. can be listed. And then, polyfunctional bisphenol epoxy resins such as the hydroxyl group of solid bisphenol epoxy resin and epihalohydrin reactions such as epichlorohydrin can also be listed. For example, as biphenol type diglycidyl ether, jER YL-6056 manufactured by Mitsubishi Chemical Corporation, as bimethylol type diglycidyl ether, jER YL-4000 manufactured by Mitsubishi Chemical Corporation, as biphenol type diglycidyl ether, bisphenol F type epoxy resins such as Epiclon 830S manufactured by DIC Corporation, bisphenol S type epoxy resins such as Epiclon EXA1514 manufactured by DIC Corporation, as naphthalene type diglycidyl ether, HP-4032 manufactured by DIC Corporation, etc. These epoxy resins can be used alone or in combination of two or more.

[0032] Representative substances of the (b) unsaturated monocarboxylic acid include acrylic acid, methacrylic acid, or further, unsaturated dibasic acid anhydride adducts of hydroxyl acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, phenyl glycidyl (meth)acrylate, and caprolactone (meth)acrylate adducts. Among them, acrylic acid and / or methacrylic acid are particularly preferred. These unsaturated monocarboxylic acids can be used alone or in combination of two or more.

[0033] In addition, in this specification, "(meth)acrylic acid" is a term that collectively refers to acrylic acid and methacrylic acid, and other similar expressions are the same.

[0034] The alcoholic hydroxyl group of the epoxy acrylate compound generated by the above reaction is reacted with (c) polyacid anhydride to obtain (A) carboxyl-containing resin. In the reaction, the amount of (c) polyacid anhydride is adjusted so that the acid value of (A) carboxyl-containing resin is usually in the range of 30 to 150 mgKOH / g, preferably 40 to 120 mgKOH / g. When the acid value of (A) carboxyl-containing resin is in the above range, the solubility in alkaline solution is easily within a suitable range, the development of the formed coating film becomes easy, and the development of the exposed part is easily controlled by the exposure conditions.

[0035] The reaction is carried out in the presence or absence of an organic solvent and in the presence of a polymerization inhibitor such as hydroquinone or oxygen, usually at about 50 to 130° C. At this time, a tertiary amine, a quaternary ammonium salt, an imidazole compound, a phosphorus compound or the like may be added as a catalyst as necessary.

[0036] As the above-mentioned (c) polyacid anhydride, alicyclic dibasic acid anhydrides such as methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, norbornene dicarboxylic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, and aliphatic or aromatic polyacid anhydrides such as succinic anhydride, maleic anhydride, itaconic anhydride, octenylsuccinic anhydride, pentadecene succinic anhydride, phthalic anhydride, and 1,2,4-tricarboxylic anhydride can be cited. These polyacid anhydrides can be used alone or in combination of two or more.

[0037] As specific examples of other (A) carboxyl group-containing resins, the following compounds (either oligomers or polymers) are preferred.

[0038] The following can be listed:

[0039] (1) Carboxyl group-containing resin obtained by copolymerizing unsaturated carboxylic acid such as (meth)acrylic acid with one or more other compounds having unsaturated double bonds,

[0040] (2) In a copolymer of an unsaturated carboxylic acid such as (meth)acrylic acid and one or more other compounds having an unsaturated double bond, an ethylenically unsaturated group is added using a compound having an epoxy group and an unsaturated double bond in one molecule such as glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, (meth)acrylic acid chloride, etc., to obtain a photosensitive carboxyl-containing resin,

[0041] (3) a photosensitive carboxyl-containing resin obtained by reacting a copolymer of a compound having an epoxy group and an unsaturated double bond in one molecule such as glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate with an unsaturated double bond other than the compound with an unsaturated carboxylic acid such as (meth)acrylic acid, and reacting the secondary hydroxyl group generated by the reaction with a polyacid anhydride;

[0042] (4) a photosensitive carboxyl-containing resin obtained by reacting a copolymer of an acid anhydride having an unsaturated double bond such as maleic anhydride and a compound having an unsaturated double bond other than maleic anhydride with a compound having a hydroxyl group and an unsaturated double bond in one molecule such as 2-hydroxyethyl (meth)acrylate;

[0043] (5) a photosensitive carboxyl-containing resin containing hydroxyl groups and carboxyl groups, obtained by reacting a hydroxyl-containing polymer such as a polyvinyl alcohol derivative with a saturated or unsaturated polyacid anhydride, and then reacting the resulting carboxylic acid with a compound having an epoxy group and an unsaturated double bond in one molecule;

[0044] (6) a photosensitive carboxyl-containing resin obtained by reacting a reaction product of a polyfunctional epoxy compound, an unsaturated monocarboxylic acid, and a compound having an alcoholic hydroxyl group reactive with an epoxy group and a reactive group other than the alcoholic hydroxyl group in one molecule with a saturated or unsaturated polybasic acid anhydride;

[0045] (7) a photosensitive carboxyl-containing resin obtained by reacting a polyfunctional oxetane compound having at least two oxetane rings in one molecule with an unsaturated monocarboxylic acid, and reacting the primary hydroxyl group in the obtained modified oxetane resin with a saturated or unsaturated polybasic acid anhydride;

[0046] (8) a photosensitive carboxyl-containing resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with an alkylene epoxy compound such as ethylene oxide or propylene oxide, and reacting the reaction product with a monocarboxylic acid containing an unsaturated group, and reacting the reaction product with a polyacid anhydride.

[0047] (9) a photosensitive carboxyl-containing resin 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, and a monocarboxylic acid containing an unsaturated group, and reacting the reaction product with a polyacid anhydride; and

[0048] (10) A photosensitive carboxyl-containing resin obtained by reacting a polyfunctional epoxy resin with an unsaturated monocarboxylic acid, and then reacting the resulting carboxyl-containing resin with a polyacid anhydride, and then reacting the resulting carboxyl-containing resin with a compound having one oxirane ring and one or more ethylenically unsaturated groups in the molecule, etc., but the present invention is not limited to these substances.

[0049] Among these examples, particularly preferred is the carboxyl group-containing resin (2) described above.

[0050] Examples of the (B) photopolymerization initiator constituting the photocurable resin composition of the present invention include:

[0051] Benzoin and benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether;

[0052] Acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, and 1-hydroxycyclohexyl phenyl ketone;

[0053] Aminoacetophenones such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-butanone-1, and N,N-dimethylaminoacetophenone;

[0054] Anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone;

[0055] Thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone;

[0056] Ketals such as acetophenone dimethyl ketal and benzil dimethyl ketal;

[0057] Benzophenones such as benzophenone, methyl benzophenone, 4,4'-dichlorobenzophenone, 4,4'-bis(diethylamino)benzophenone, and 4-benzoyl-4'-methyldiphenyl sulfide;

[0058] Monoaryl phosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide;

[0059] Diaryl phosphine oxides such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide;

[0060] Metallocenes such as bis(1-(2,4-difluorophenyl)-3-pyrrolyl) titanocene, and the like.

[0061] These photopolymerization initiators can be used alone or in combination of two or more.

[0062] Furthermore, the (B) photopolymerization initiator can be used in combination with one or more of tertiary amine photosensitizers or photoinitiator aids such as N,N-dimethylaminobenzoic acid ethyl ester, N,N-dimethylaminobenzoic acid isopentyl ester, 4-dimethylaminobenzoic acid pentyl ester, triethylamine, triethanolamine, etc.

[0063] The content of the above-mentioned (B) photopolymerization initiator (the total amount of the photosensitizer or photoinitiator auxiliary when using them) is, for example, 1 to 30 parts by weight, preferably 5 to 25 parts by weight, relative to 100 parts by weight (solid matter content, the same below) of the (A) carboxyl-containing resin. When the content of the (B) photopolymerization initiator is within the above range, the composition is easily cured by irradiation with active energy rays, and appropriate coating properties can be obtained even if the irradiation time is short. On the other hand, even if the photopolymerization initiator is added in an amount greater than the above range, the photocurability does not change, which is not economically preferred.

[0064] Furthermore, the photopolymerization initiator (B) preferably contains a photopolymerization initiator (B1) having an absorbance of 1.0 or more at a wavelength of 450 nm in a 0.1 wt % 1-methyl-2-pyrrolidone solution. By containing the photopolymerization initiator (B1), poor curing of the compound containing an ethylenically unsaturated group and an epoxy group as the component (C) can be suppressed. As a result, the curing property of the composition in the center of the through hole is improved, voids and cracks are less likely to occur, and cavitation resistance can be improved.

[0065] Examples of commercially available products of the photopolymerization initiator (B1) include Omnirad 784 manufactured by IGM Resin, GR-FMT manufactured by Hubei Gurun Technology Co., Ltd., Chivacure 534 manufactured by Chitec Technology, and JMT-784 manufactured by Yueyang Jinmaotai Technology Co., Ltd.

[0066] As the photopolymerization initiator (B1), metallocenes such as bis(1-(2,4-difluorophenyl)-3-pyrrolyl)titanocene are preferred.

[0067] The content of the photopolymerization initiator (B1) is 0.05 to 10 parts by weight, preferably 0.1 to 5 parts by weight, and more preferably 0.1 to 2 parts by weight, relative to 100 parts by weight of the carboxyl group-containing resin (A). When the amount of the photopolymerization initiator (B1) is within the above range, particularly excellent effects can be exerted.

[0068] The photocurable resin composition of the present invention uses (C) a compound containing an ethylenically unsaturated group and an epoxy group, so that even if the ethylenically unsaturated group in some molecules does not react when irradiated with active energy rays, the epoxy groups in these molecules can react with the carboxyl groups of the carboxyl group-containing resin (A). As a result, poor curing of the compound containing an ethylenically unsaturated group and an epoxy group does not occur, the occurrence of voids and cracks can be suppressed, and cavitation resistance can be improved.

[0069] (C) The compound containing an ethylenically unsaturated group and an epoxy group is a compound containing at least an ethylenically unsaturated group and an epoxy group.

[0070] The above-mentioned ethylenically unsaturated groups can include aliphatic ethylenically unsaturated groups and alicyclic ethylenically unsaturated groups. Among them, aliphatic ethylenically unsaturated groups are preferred. As aliphatic ethylenically unsaturated groups, straight or branched aliphatic ethylenically unsaturated groups with 2 to 12 carbon atoms are preferred, and straight or branched aliphatic ethylenically unsaturated groups with 2 to 8 carbon atoms are more preferred. As representative examples of the above-mentioned ethylenically unsaturated olefins, for example, vinyl, acryloyl, methacryloyl, vinylidene, acryloyl, allyl, 2-methylacryloyl, 1-butenyl, 2-butenyl, 3-butenyl, etc. can be listed. As such (C) compounds containing ethylenically unsaturated groups and epoxy groups, compounds having epoxy groups and (meth)acryloyl groups, and compounds having glycidyl groups and (meth)acryloyl groups can be listed.

[0071] From the perspective of photocrosslinking, curing speed, etc., the compound (C) containing an ethylenically unsaturated group and an epoxy group of the present invention preferably includes a multifunctional compound (C) containing an ethylenically unsaturated group and an epoxy group. That is, it preferably includes a compound containing two or more ethylenically unsaturated groups and / or two or more epoxy groups. The compound (C) containing an ethylenically unsaturated group and an epoxy group of the present invention also preferably has an isocyanurate skeleton.

[0072] That is, as the (C) compound containing an ethylenically unsaturated group and an epoxy group of the present invention, by including a polyfunctional (C) compound containing an ethylenically unsaturated group and an epoxy group and / or a (C) compound containing an ethylenically unsaturated group and an epoxy group having an isocyanurate skeleton, the occurrence of voids and cracks can be further suppressed and the cavitation resistance can be improved.

[0073] Commercially available products of the compound (C) containing an ethylenically unsaturated group and an epoxy group include, for example, LIGHT ESTER G manufactured by Kyoeisha Chemical Co., Ltd., DA-MGIC and MA-DGIC manufactured by Shikoku Chemical Industry Co., Ltd. These compounds (C) containing an ethylenically unsaturated group and an epoxy group may be used alone or in combination of two or more.

[0074] The content of the compound containing an ethylenically unsaturated group and an epoxy group (C) of the present invention is usually 1 to 60 parts by weight relative to 100 parts by weight of the carboxyl group-containing resin (A). It is preferably 5 to 40 parts by weight, more preferably 5 to 30 parts by weight, and particularly preferably 5 to 10 parts by weight. When it is within the above range, a particularly excellent effect can be exerted.

[0075] For the purpose of improving properties such as adhesion and hardness, the inorganic filler (D) may be a known and commonly used inorganic filler such as barium sulfate, barium titanate, silicon oxide powder, fine powder silicon oxide, amorphous silicon, talc, clay, calcium carbonate, aluminum oxide, aluminum hydroxide, mica powder, etc. These inorganic fillers may be used alone or in combination of two or more.

[0076] The content of the inorganic filler (D) is usually preferably 60 to 200 parts by weight, preferably 80 to 200 parts by weight, based on 100 parts by weight of the carboxyl group-containing resin (A).

[0077] The photocurable resin composition of the present invention contains (E) a thermosetting resin. As the (E) thermosetting resin, blocked isocyanate compounds, amino resins, maleimide compounds, benzoxazine resins, carbodiimide resins, cyclocarbonate compounds, 1,3-epoxypropylene compounds, episulfide resins, melamine derivatives, etc. can be used.

[0078] Since the photocurable resin composition of the present invention is used for filling the through-holes of printed circuit boards and protecting the circuits, it is preferred that a liquid epoxy resin is contained as (E) thermosetting resin. If a liquid epoxy resin is contained, the occurrence of voids and cracks can be suppressed, and cavitation resistance can be improved due to the reduction of the content of organic solvents. Based on such a viewpoint, in the photocurable resin composition of the present invention, it is preferred that (E1) a liquid epoxy resin is further contained as (E) a thermosetting resin. As a liquid epoxy resin, epoxy resins such as bisphenol A type, bisphenol F type, aminophenol type, and phenol novolac type can be suitably used.

[0079] In the photocurable resin composition of the present invention, these epoxy resins may be used alone or in combination of two or more. A solid epoxy resin may be used instead of a liquid epoxy resin.

[0080] In this specification, a liquid epoxy resin refers to an epoxy resin that is liquid at 20°C, and a solid epoxy resin refers to an epoxy resin that is solid at 20°C.

[0081] The determination of liquid state is carried out in accordance with the "Method for Confirming Liquid State" in Appendix 2 of the Ministerial Ordinance on the Test and Properties of Dangerous Substances (Ministry of Autonomy Ordinance No. 1 of 1919).

[0082] (1) Device

[0083] Constant temperature water tank:

[0084] A constant temperature water tank having a depth of 150 mm or more and equipped with a stirrer, a heater, a thermometer, and an automatic temperature regulator (a regulator capable of controlling the temperature at ±0.1° C.) was used.

[0085] In addition, the determination of the epoxy resin used in the following examples all used a combination of a low-temperature constant-temperature water tank (Model BU300) and an immersion constant-temperature device stirring controller (Model BF500) manufactured by YAMATO Scientific Co., Ltd. 22 liters of tap water were added to the low-temperature constant-temperature water tank (Model BU300), the power of the stirring controller (Model BF500) assembled thereon was turned on and the set temperature (20°C or 40°C) was set, and the water temperature was fine-tuned with the stirring controller (Model BF500) to maintain it at the set temperature ±0.1°C. Of course, any device that can perform the same adjustment can be used.

[0086] test tube:

[0087] As a test tube, Figure 1 As shown in the figure, a flat-bottomed cylindrical transparent glass test tube with an inner diameter of 30 mm and a height of 120 mm is used, and the marking lines 31 and 32 are respectively made at the heights of 55 mm and 85 mm from the bottom of the tube, and the test tube mouth is sealed with a rubber plug 33a as a liquid state determination test tube 30a, and a temperature measurement test tube 30b with the same size and the same marking lines, the test tube mouth is sealed with a rubber plug 33b with a hole for inserting and supporting a thermometer in the center, and a thermometer 34 is inserted into the rubber plug 33b. Hereinafter, the marking line at a height of 55 mm from the bottom of the tube is referred to as "A line", and the marking line at a height of 85 mm from the bottom of the tube is referred to as "B line".

[0088] As the thermometer 34, a thermometer for measuring freezing point specified in JIS B7410 (1982) "Glass thermometer for petroleum testing" (SOP-58 scale range 20 to 50°C) is used, but any thermometer capable of measuring a temperature range of 0 to 50°C may be used.

[0089] (2) Experimental implementation steps

[0090] Place the samples that have been placed in the atmosphere at 20±5℃ for more than 24 hours in Figure 1 The liquid determination test tube 30a shown in (a) and Figure 1 The temperature measuring test tube 30b shown in (b) of FIG. 30a and 30b are placed upright in a low-temperature constant-temperature water tank so that the B line is below the water surface. The lower end of the thermometer is located 30 mm lower than the A line.

[0091] Keep the sample temperature as it is for 10 minutes after it reaches the set temperature ±0.1°C. After 10 minutes, take the liquid determination test tube 30a out of the low-temperature constant temperature water tank and immediately put it horizontally on a horizontal test bench. Use a stopwatch to measure and record the time it takes for the front end of the liquid surface in the test tube to move from line A to line B. If the time measured at the set temperature is within 90 seconds, the sample is judged as liquid, and if it exceeds 90 seconds, it is judged as solid.

[0092] Commercially available products of the (E) thermosetting resin include, for example, bisphenol A type epoxy resins such as jER828, jER834, jER1001, and jER1004 manufactured by Mitsubishi Chemical Corporation, Epiclon840, Epiclon850, Epiclon1050, and Epiclon2055 manufactured by DIC Corporation, and Epotote YD-011, YD-013, YD-127, and YD-128 (all trade names) manufactured by Nippon Steel Chemicals & Materials Co., Ltd.; jER YL903 manufactured by Mitsubishi Chemical Corporation, Epiclon152 and Epiclon165 manufactured by DIC Corporation, and Epotote Brominated epoxy resins such as YDB-400 and YDB-500; jER152 and jER154 manufactured by Mitsubishi Chemical, EpiclonN-730, EpiclonN-770 and EpiclonN-865 manufactured by DIC, Epotote YDCN-701 and YDCN-704 manufactured by Nippon Steel Chemical & Materials, EPPN-201, EOCN-1025, EOCN-100, EOCN-104S and RE-306 (all trade names) manufactured by Nippon Kayaku; bisphenol F epoxy resins such as Epiclon830 manufactured by DIC, jER807 manufactured by Mitsubishi Chemical, Epotote YDF-170, YDF-175 and YDF-2004 (all trade names) manufactured by Nippon Steel Chemical & Materials; Epotote manufactured by Nippon Steel Chemical & Materials ST-2004, ST-2007, ST-3000 (trade names) and other hydrogenated bisphenol A type epoxy resins; jER604 manufactured by Mitsubishi Chemical Corporation, Epotote YH-434 manufactured by Nippon Steel Chemical & Materials Co., Ltd., Sumiepoxy ELM-120 manufactured by Sumitomo Chemical Co., Ltd. (all trade names) and other glycidylamine type epoxy resins; DAICEL CHEMICAL INDUSTRIES, LTD.Alicyclic epoxy resins such as Celoxide 2021 (trade name) manufactured by Mitsubishi Chemical Corporation; trihydroxyphenylmethane epoxy resins such as YL-933 manufactured by Mitsubishi Chemical Corporation, EPPN-501, EPPN-502 (all trade names) manufactured by Nippon Kayaku Co., Ltd.; bixylenol-type or biphenol-type epoxy resins such as YL-6056, YX-4000, YL-6121 (all trade names) manufactured by Mitsubishi Chemical Corporation, or mixtures thereof; EBPS-20 0, bisphenol S type epoxy resins such as EPX-30 manufactured by ADEKA and EXA-1514 manufactured by DIC (both trade names); bisphenol A novolac type epoxy resins such as jER157S (trade name) manufactured by Mitsubishi Chemical; tetrahydroxyphenylethane type epoxy resins such as jERYL-931 (trade name) manufactured by Mitsubishi Chemical Corporation; heterocyclic epoxy resins such as TEPIC (trade name) manufactured by Nissan Chemical Industries, Ltd.; Blemmer Phthalic acid diglycidyl ester resins such as DGT (trade name); tetraglycidyl xylenoyl ethane resins such as ZX-1063 (trade name) manufactured by Nippon Steel Chemical & Materials Co., Ltd.; naphthyl epoxy resins such as ESN-190 and ESN-360 manufactured by Nippon Steel Chemical & Materials Co., Ltd., HP-4032, EXA-4750, and EXA-4700 (all trade names) manufactured by DIC Co., Ltd.; epoxy resins having a dicyclopentadiene skeleton such as HP-7200 and HP-7200H (all trade names) manufactured by DIC Co., Ltd.; methacrylate glycidyl copolymer epoxy resins such as CP-50S and CP-50M (all trade names) manufactured by NOF Corporation; and copolymer epoxy resins of cyclohexylmaleimide and methacrylate glycidyl ester. These epoxy resins can be used alone or in combination of two or more. .

[0093] The content of the (E) thermosetting resin is usually preferably 10 to 70 parts by weight, preferably 10 to 60 parts by weight, based on 100 parts by weight of the (A) carboxyl group-containing resin.

[0094] From the perspective of further reducing voids and cracks after curing and further improving cavitation resistance, the photocurable resin composition of the present invention preferably further contains (F) a reactive diluent having no epoxy group and having an ethylenically unsaturated group. The reactive diluent can be any substance that functions as a diluent for the composition, preferably a compound having a molecular weight of 700 or less.

[0095] As the reactive diluent (F) having no epoxy group but having an ethylenically unsaturated group used in the present invention, a monofunctional, difunctional, or trifunctional or higher functional (meth)acrylate monomer is preferably used, and a difunctional, or trifunctional or higher functional (meth)acrylate monomer is more preferably used.

[0096] Examples of the monofunctional (meth)acrylates include 2-hydroxyethyl (meth)acrylate, carbitol (meth)acrylate, isobornyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-(meth)acryloylethoxy-2-hydroxypropyl phthalate, etc. Examples of commercially available products include ARONIX M-101, ARONIX M-111, ARONIX M-114 (all produced by Toagosei Co., Ltd.), KAYARAD TC-110S, KAYARAD TC-120S (all produced by Nippon Kayaku Co., Ltd.), and Viscoat 158 ​​and Viscoat 2311 (all produced by Osaka Organic Chemical Industry Co., Ltd.).

[0097] Examples of the bifunctional (meth)acrylate include ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, bisphenoxyethanol fluorene diacrylate, tricyclodecane dimethanol diacrylate, etc. Examples of commercially available products include ARONIX M-210, ARONIX M-240, ARONIX M-6200 (all manufactured by Toagosei Co., Ltd.), KAYARAD HDDA, KAYARAD HX-220, KAYARAD R-604 (all manufactured by Nippon Kayaku Co., Ltd.), Viscoat 260, Viscoat 312, Viscoat 335HP (all manufactured by Osaka Organic Chemical Industry Co., Ltd.), etc.

[0098] Examples of the trifunctional or higher-functional (meth)acrylate include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tri((meth)acryloyloxyethyl)phosphate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. Examples of commercially available products include ARONIX M-309, ARONIX M-400, ARONIX M-402, ARONIX M-405, ARONIX M-450, ARONIX M-7100, ARONIX M-8030, ARONIX M-8060, ARONIX M-1310, ARONIX M-1600, ARONIX M-1960, ARONIX M-8100, ARONIX M-8530, ARONIX M-8560, ARONIX M-9050, and ARONIX TO-1450 (all produced by Toagosei Co., Ltd.), KAYARAD TMPTA, KAYARAD DPHA, KAYARAD DPCA-20, KAYARAD DPCA-30, KAYARAD DPCA-60, and KAYARAD DPCA-120 (all produced by Nippon Kayaku Co., Ltd.), and Viscoat 295, Viscoat 300, Viscoat 360, Viscoat GPT, Viscoat 3PA, Viscoat 400 (all manufactured by Osaka Organic Chemical Industry Co., Ltd.), etc. These monofunctional, difunctional, or trifunctional or higher-functional (meth)acrylates may be used alone or in combination.

[0099] The content of the reactive diluent (F) having no epoxy group but having an ethylenically unsaturated group is 1 to 60 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the carboxyl group-containing resin (A).

[0100] In the present invention, an organic solvent may be used to adjust the viscosity to be suitable for the coating method.

[0101] Examples of such organic solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, and carbitol acetate; alcohols such as ethanol, propanol, ethylene glycol, and propylene glycol; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, naphtha, hydrogenated naphtha, and solvent naphtha, and the like.

[0102] The content of the organic solvent is preferably 30% by weight or less based on the total amount of the solder resist composition of the present invention.

[0103] In the present invention, a curing catalyst can be used to improve the toughness, adhesion, heat resistance and electroless plating resistance of the coating film. As a curing catalyst, for example, imidazole derivatives such as 2E4MZ-AZINE, C11Z-AZINE, 2PHZ, etc.; guanamines such as acetoguanamine and benzoguanamine; polyamines such as dicyandiamide, urea, urea derivatives, melamine, polyhydrazides, etc., which are well-known and commonly used curing agents or curing accelerators can be used. These curing agents or curing accelerators can be used alone or in combination of two or more.

[0104] Furthermore, in the present invention, known and commonly used inorganic pigments, organic pigments, etc. can be used for coloring as needed. Examples thereof include phthalocyanine blue, phthalocyanine green, disazo yellow, anthraquinone yellow pigments, benzimidazolone, titanium oxide, carbon black, and the like.

[0105] Furthermore, as required, known and commonly used fluidity adjusters such as fine powder silica, organic bentonite, montmorillonite, etc., known and commonly used defoaming agents or leveling agents such as silicone, fluorine-based, polymer-based, etc., adhesion imparting agents such as imidazole-based, thiazole-based, triazole-based, silane coupling agents, known and commonly used matting agents, etc. can also be formulated.

[0106] The photocurable resin composition of the present invention is preferably obtained by mixing the above-mentioned ingredients at the above-mentioned ratio, and uniformly mixing and dispersing them using a roll mill or the like.

[0107] As described above, the photocurable resin composition of the present invention is formed into a photocurable resin coating filled in a through hole through the following steps. That is, a coating film forming step of filling the photocurable resin composition of the present invention in a through hole, applying it on a surface, and drying it, a photocuring treatment step of selectively applying active energy rays to the coating film obtained by the coating film forming step, an alkali developing step of removing the unirradiated portion using an alkali developer to obtain a pattern after the photocuring treatment step, and a curing step of heating and curing the pattern obtained in the alkali developing step to form a cured product pattern.

[0108] (1) Coating film forming process

[0109] In this process, the photocurable resin composition of the present invention is filled in the through-hole portion of the printed circuit board on which the circuit is pre-formed by printing. The filling is performed using a screen that can selectively fill the through-hole portion, usually starting from one side. The photocurable resin composition of the present invention is applied to both sides after filling by a method such as screen printing, curtain coating, spraying or roller coating. In the case of coating by screen printing, the above-mentioned step of filling the through-hole can be omitted, and coating and filling the through-hole can be performed simultaneously.

[0110] After coating, the volatile components contained in the coating film are removed at a temperature of 60 to 90°C, and the coating film is dried to form a dry coating film. At this time, it is important to select the temperature and time so that the volatile components contained in the composition filled in the through hole can also be removed. It should be noted that after the photocurable resin composition is filled in the through hole, before coating on the surface of the printed circuit board, a process of drying the composition in the through hole and a process of irradiating active energy rays for semi-curing the composition in the through hole can also be implemented.

[0111] (2) Photocuring (exposure) process

[0112] In this step, the coating film obtained in the above step (1) is selectively irradiated with active energy rays. Here, for example, in order to perform exposure, active energy rays can be selectively irradiated through a photomask. As the exposure light source, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, etc. are generally used.

[0113] The amount of light used in the exposure can be appropriately selected depending on the weight average molecular weight, monomer ratio, content of the resin component, the type and content of the photopolymerizable compound, the weight and content of the photopolymerization initiator, the type and content of the photopolymerization initiation aid, and the like.

[0114] (3) Alkali Development Process

[0115] The exposed coating film after the above step (2) is developed. During development, a developer is sprayed onto the exposed coating film in a shower to remove the unexposed portion of the coating film. Examples of the developer include aqueous solutions of dilute alkaline compounds such as sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, and organic amines. By development, the unexposed portion is removed to form a coating film pattern. After development, the coating film can usually be washed with water and dried.

[0116] (4) Curing process

[0117] The coating film pattern on the substrate after the above step (3) is cured by heating to be thermally cured.

[0118] For the purpose of suppressing the curing shrinkage of the coating film in the through-holes and suppressing the bleeding and cavitation of the coating film, the thermal curing is performed by step curing.

[0119] Step curing is a method of heating and curing in two or three steps at different temperatures and times. The temperature and time are appropriately selected and used, usually at 60-80°C for 30-60 minutes as the first stage, at 100-120°C for 0-40 minutes as the second stage, and then at 150-160°C for 40-90 minutes as the third stage. In order to fully obtain electroless tin plating resistance and electroless gold plating resistance, it is preferred to make the step curing conditions as short as possible within the range that does not produce voids.

[0120] Through the above-described steps, a cured coating film having few voids and cracks after curing and excellent cavitation resistance can be formed.

[0121] Example

[0122] The present invention will be described in more detail below based on Examples and Comparative Examples, but the present invention is not limited to the following Examples. It should be noted that "parts" or "%" in Examples and Comparative Examples are by weight unless otherwise specified.

[0123] Examples 1 to 6 and Comparative Examples 1 to 2

[0124] The components were mixed in the proportions shown in Table 1 (values ​​are in parts by mass) and kneaded using a three-roll mill to prepare an alkali-soluble photocurable resin composition. It should be noted that (A) carboxyl group-containing resin in Table 1 is 100 parts by weight in terms of solid content.

[0125] The photocurable resin composition was printed on a through-hole substrate with a thickness of 1.6 mm and a hole diameter of 0.25 mm by screen printing using a 90-mesh polyester screen with a pattern capable of filling the through-holes. Further, both surfaces were fully coated with a 90-mesh polyester screen and dried in a hot air dryer at 75° C. for 30 minutes.

[0126] Then, HMW-680GW from ORC Corporation was used to generate 500 J / cm 2 The coating film was exposed to ultraviolet light with an exposure amount of 1000 nm. Then, a hot air circulation dryer was used to heat and cure the film at 80°C for 30 minutes, 110°C for 30 minutes, and 150°C for 40 minutes to produce a test substrate. The test substrate with a cured film was tested for the cross-sectional state and cavitation resistance of the cured product according to the test method and evaluation method described below. The evaluation results of the above tests are shown in Table 2.

[0127] Synthesis example 1

[0128] In a 2-liter separable flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen conduit, 900 parts of diethylene glycol dimethyl ether as a solvent, 21.4 parts of peroxidized 2-ethylhexanoic acid tert-butyl ester (PERBUTYL O manufactured by Nippon Oil & Fats Co., Ltd.) as a polymerization initiator are added and heated to 90°C. After heating, 309.9 parts of methacrylic acid, 116.4 parts of methyl methacrylate, 109.8 parts of lactone-modified 2-hydroxyethyl methacrylate (PLACCEL FM1 manufactured by DAICEL CHEMICAL INDUSTRIES, LTD.) and 21.4 parts of bis (4-tert-butylcyclohexyl) peroxydicarbonate (PEROYL TCP manufactured by Nippon Oil & Fats Co., Ltd.) as a polymerization initiator are added dropwise thereto in a total of 3 hours, and then aged for 6 hours to obtain a carboxyl-containing copolymer resin. It should be noted that the reaction is carried out under a nitrogen atmosphere.

[0129] Then, 363.9 parts of 3,4-epoxycyclohexylmethyl acrylate (CYCLOMER A200 manufactured by DAICEL CHEMICAL INDUSTRIES, LTD.), 3.6 parts of dimethylbenzylamine as a ring-opening catalyst, and 1.80 parts of hydroquinone monomethyl ether as a polymerization inhibitor were added to the obtained carboxyl-containing copolymer resin, and the mixture was heated to 100° C. and stirred to perform a ring-opening addition reaction of the epoxy group. After 16 hours, a solution of a carboxyl-containing resin having an acid value of 108.9 mgKOH / g, a weight average molecular weight of 25,000, and no aromatic ring was obtained.

[0130] (1) Cross-sectional state after curing

[0131] The test substrate was cut at the through-hole portion, and the cured product in the cross section was observed with an optical microscope to confirm whether voids and cracks occurred in 50 through-holes.

[0132] ◎: No more than 5 voids or cracks occurred in 500 holes

[0133] ○: 6 to 10 voids and cracks occurred in 500 holes

[0134] △: 11 to 20 voids and cracks occurred in 500 holes

[0135] ×: 21 or more voids and cracks occurred in 500 holes

[0136] (2) Cavitation resistance

[0137] The test substrate was immersed once in a 260° C. solder bath using rosin solder for 30 seconds, and then peeled off to check the peeling state of the cured film in the through-hole portion.

[0138] ◎: 0 out of 500 holes peeled off

[0139] ○: 10 or less holes peeled off in 500 holes

[0140] △: 11 to 50 holes peeled off out of 500 holes

[0141] ×: 51 or more holes in 500 holes peeled off

[0142] Table 1

[0143]

[0144] Table 2

[0145]

[0146] *1: Synthesis example 1

[0147] *2: KAYARAD ZAR-1035: Bisphenol A epoxy acrylate resin, manufactured by Nippon Kayaku Co., Ltd.

[0148] *3: Omnirad369: 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, manufactured by IGM Resins

[0149] *4: ITX: 2-isopropylthioxanthone, manufactured by Yangzhou Suntory Chemical Co., Ltd.

[0150] *5: Omnirad784: bis(1-(2,4-difluorophenyl)-3-pyrrolyl) titanocene, manufactured by IGM Resins, absorbance at 450 nm in a 0.1 wt% 1-methyl-2-pyrrolidone solution is 1.0 or more

[0151] *6: LIGHT ERTER G: Glycidyl methacrylate, manufactured by Kyoeisha Chemical Co., Ltd.

[0152] Structural formula

[0153] *7: MA-DGIC: Isocyanuric acid derivative, manufactured by Shikoku Chemical Industry Co., Ltd. Structural formula

[0154]

[0155] *8: DA-MGIC: Isocyanuric acid derivative, manufactured by Shikoku Chemical Industry Co., Ltd. Structural formula

[0156]

[0157] *9: A-DCP: diethyl tricyclodecanedioate, manufactured by Shin-Nakamura Chemical Industry Co., Ltd. *10: DPHA: dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd.

[0158] *11: B-30: Barium sulfate, average particle size 0.2 μm, manufactured by Sakai Chemical Industry Co., Ltd.

[0159] *12: A-8: Crystalline silica, manufactured by UNIMI

[0160] *13: N770CA75: Solid multifunctional phenol novolac type epoxy resin, manufactured by DIC Corporation

[0161] *14: JER-828: Liquid bisphenol A epoxy resin, epoxy equivalent: 184-194, manufactured by Mitsubishi Chemical Corporation

[0162] In Examples 1 to 7, by containing (C) a compound containing an ethylenically unsaturated group and an epoxy group, a cured film having few voids and cracks after curing and excellent cavitation resistance was obtained. Furthermore, when (F) a reactive diluent having no epoxy group but having an ethylenically unsaturated group was added, the cavitation resistance was further improved. On the other hand, in the comparative example not containing (C) a compound containing an ethylenically unsaturated group and an epoxy group, a cured film having many voids and cracks after curing and poor cavitation resistance was obtained.

[0163] As shown in Tables 1 and 2, the photocurable resin composition of the present invention can provide a cured film having few voids and cracks after curing and excellent cavitation resistance, and a printed circuit board formed using the same. It can be seen that the photocurable resin composition of the present invention can be suitably used as a solder resist for through-hole filling of a printed circuit board.

Claims

1. A solder resist composition for through-hole filling of a printed circuit board, characterized in that: Containing (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a compound containing an ethylenically unsaturated group and an epoxy group, (D) an inorganic filler, and (E) a thermosetting resin, The (A) carboxyl group-containing resin comprises a carboxyl group-containing resin obtained by reacting a reaction product of (a) a polyfunctional epoxy compound and (b) a monocarboxylic acid containing an unsaturated group with (c) a polyacid anhydride. The (a) multifunctional epoxy compound is at least any one of bisphenol A type, hydrogenated bisphenol A type, bisphenol F type and bisphenol S type.

2. The solder resist composition for through-hole filling of a printed circuit board according to claim 1, characterized in that: As the (B) photopolymerization initiator, a (B1) photopolymerization initiator having an absorbance of 1.0 or more at a wavelength of 450 nm in a 0.1% by weight 1-methyl-2-pyrrolidone solution is contained.

3. The solder resist composition for through-hole filling of a printed circuit board according to claim 2, characterized in that: The content of the photopolymerization initiator (B1) is 0.05 to 1.0 part by weight based on 100 parts by weight of the carboxyl group-containing resin (A).

4. The solder resist composition for through-hole filling of a printed circuit board according to claim 1, characterized in that: The content of the inorganic filler (D) is 60 to 200 parts by weight based on 100 parts by weight of the carboxyl group-containing resin (A).

5. The solder resist composition for through-hole filling of a printed circuit board according to claim 1, characterized in that: The content of the (E) thermosetting resin is 10 to 70 parts by weight based on 100 parts by weight of the (A) carboxyl group-containing resin.

6. The solder resist composition for through-hole filling of a printed circuit board according to claim 1, characterized in that: (F) A reactive diluent having no epoxy group but having an ethylenically unsaturated group is further contained.

7. The solder resist composition for through-hole filling of a printed circuit board according to claim 6, characterized in that: The content of the reactive diluent (F) having no epoxy group but having an ethylenically unsaturated group is 1 to 60 parts by weight based on 100 parts by weight of the carboxyl group-containing resin (A).

8. The solder resist composition for through-hole filling of a printed circuit board according to claim 1, characterized in that: The content of the compound (C) containing an ethylenically unsaturated group and an epoxy group is 1 to 60 parts by weight based on 100 parts by weight of the carboxyl group-containing resin (A).

9. The solder resist composition for through-hole filling of a printed circuit board according to claim 1, characterized in that: The (C) compound containing an ethylenically unsaturated group and an epoxy group is a polyfunctional compound containing an ethylenically unsaturated group and an epoxy group.

10. The solder resist composition for filling through-holes of a printed circuit board according to any one of claims 1 to 9, characterized in that: The (C) compound containing an ethylenically unsaturated group and an epoxy group has an isocyanurate skeleton.

11. The solder resist composition for through-hole filling of a printed circuit board according to claim 10, characterized in that: The (E) thermosetting resin contains (E1) a liquid epoxy resin.

12. A printed wiring board having a cured product of the solder resist composition for through-hole filling of a printed wiring board according to any one of claims 1 to 11.

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