Alkaline developable resin composition, photocurable dry film thereof, cured product thereof, and printed circuit board formed using the same.

Abstract

The present invention provides an alkaline developable resin composition that has good printability (covering properties, sagging) and stability (tin plating resistance, boil whitening resistance), and can form a solder resist film that is excellent in all aspects of thermal shock resistance and high-temperature storage, as well as a photocurable dry film thereof and its cured product, and a printed circuit board formed using the same. [Solution] The alkaline developable resin composition contains (A) a vinyl ester resin, (B) a photopolymerization initiator, (C) an antioxidant, (D) a compound having two or more ethylenically unsaturated groups in one molecule, and (E) an inorganic filler, wherein the (E) inorganic filler contains talc, and when the total amount of the (E) inorganic filler is 100% by weight, the talc content is 50% by weight or more, and the total content of the (E) inorganic filler is 60 to 180 parts by weight per 100 parts by weight of the (A) vinyl ester resin.

Description

[Technical Field]

[0001] The present invention relates to an alkaline developable resin composition suitable for forming solder resist films on printed circuit boards, a photocurable dry film thereof, and a cured product thereof, and more particularly to an alkaline developable resin composition, a photocurable dry film thereof, and a cured product thereof, as well as a printed circuit board, that can form a solder resist film with good printability and excellent thermal shock resistance. [Background technology]

[0002] Currently, alkaline developable solder resists are used to form the solder resist film (solder resist) on some consumer printed circuit boards and most industrial printed circuit boards. These resists are exposed to ultraviolet light, then developed to form a pattern, and then completely cured (primarily cured) by heat and / or light irradiation. Furthermore, in semiconductor equipment used in vehicles such as automobiles, trains, ships, and aircraft, and in communication equipment used in special environments, solder resists for long-term, high-reliability electronic materials tend to be used as solder resists for printed circuit boards.

[0003] However, conventional alkaline-developable solder resists typically have poor crack resistance during thermal cycling and poor high-temperature storage due to thermal expansion and other reasons. While selecting barium sulfate as a filler can satisfy the general uses of solder resist, it still has poor crack resistance during thermal cycling and poor high-temperature storage, which are required for applications such as automotive. It also negatively affects the printability (covering ability, dripping) and stability (tin plating resistance, boil-whitening resistance) of the ink.

[0004] For example, the photocurable solder resist described in Patent Document 1 uses silica, barium sulfate, and talc as fillers. The curable resin composition for solder resist films described in Patent Document 2 contains a carboxyl group-containing resin, a thermosetting component, a flame retardant, and an ion scavenger, the ion scavenger being a mixture of a hydrotalcite-based ion scavenger and a non-hydrotalcite-based ion scavenger, and aluminum hydroxide is used as an inorganic filler. The curable resin composition described in Patent Document 3 is used as a permanent mask for printed circuit boards and contains a resin containing ethylenically unsaturated groups and carboxyl groups in its molecule, a photopolymerization initiator, a photopolymerizable monomer, titanium oxide surface-treated with alumina, barium sulfate and / or talc, and an organic solvent. Patent Document 4 describes a UV-curable liquid photosensitive solder resist flex ink in which the filler is barium sulfate, talc, or silica. [Prior art documents] [Patent Documents]

[0005] Patent document 1: CN114716868A Patent document 2: CN108137791A Patent document 3: CN101798432A Patent document 4: CN106380929A [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide an alkaline developable resin composition, a photocurable dry film thereof, a cured product thereof, and a printed circuit board that can form a solder resist film that has good printability (covering properties, sagging) and stability (tin plating resistance, boil whitening resistance), and is excellent in all aspects of thermal shock resistance and high-temperature storage. [Means for solving the problem]

[0007] The inventors of the present invention conducted extensive research to solve the above problems and found that fillers and antioxidants have a significant impact on the above performance. The following alkaline developable resin composition can solve the above problems and has led to the completion of the present invention. The alkaline developable resin composition contains (A) vinyl ester resin, (B) photopolymerization initiator, (C) antioxidant, (D) compound having two or more ethylenically unsaturated groups in one molecule, and (E) inorganic filler, wherein the talc content is 50% by weight or more when the total amount of (E) inorganic filler is 100% by weight, and the total content of (E) inorganic filler is 60 to 180 parts by weight per 100 parts by weight (in terms of solids) of (A) vinyl ester resin.

[0008] In other words, the alkaline developable resin composition of the present invention contains (A) a vinyl ester resin, (B) a photopolymerization initiator, (C) an antioxidant, (D) a compound having two or more ethylenically unsaturated groups in one molecule, and (E) an inorganic filler, wherein the talc content is 50% by weight or more when the total amount of the inorganic filler (E) is 100% by weight, and the total content of the inorganic filler (E) is 60 to 180 parts by weight per 100 parts by weight (in terms of solid content) of the vinyl ester resin (A).

[0009] Furthermore, it is preferable to include (F) other additives other than (B) photopolymerization initiators and (C) antioxidants.

[0010] Furthermore, it is preferable that (G) epoxy resin be included.

[0011] Furthermore, it is preferable that the material contains an organic solvent (H).

[0012] Furthermore, the amount of (C) antioxidant used is preferably 3 parts by weight or more per 100 parts by weight (in terms of solid content) of the vinyl ester resin (A).

[0013] Furthermore, it is preferable that the (E) inorganic filler further contains barium sulfate.

[0014] Furthermore, the photocurable dry film of the present invention is characterized by being obtained by applying the alkaline developable resin composition to a carrier film and drying it.

[0015] Furthermore, the cured product of the present invention is characterized by being obtained by photocuring a coating film obtained by applying the alkaline developable resin composition to copper and drying it, or by applying the alkaline developable resin composition to a carrier film, drying it, and then laminating the resulting photocurable dry film onto copper.

[0016] Furthermore, the printed circuit board of the present invention is characterized by being obtained by applying the alkaline developable resin composition to a substrate having copper circuits and drying it to obtain a coating film, or by applying the alkaline developable resin composition to a carrier film and drying it to obtain a photocurable dry film, laminating the resulting coating film onto a substrate having copper circuits, photocuring the coating film, and then heat-curing it.

[0017] The most significant feature of the alkaline developable resin composition of the present invention is that it contains (A) a vinyl ester resin, (B) a photopolymerization initiator, (C) an antioxidant, (D) a compound having two or more ethylenically unsaturated groups in one molecule, and (E) an inorganic filler, wherein the talc content is 50% by weight or more when the total amount of the inorganic filler (E) is 100% by weight, and the total content of the inorganic filler (E) is 60 to 180 parts by weight per 100 parts by weight (in terms of solid content) of the vinyl ester resin (A).

[0018] Based on the characteristic configuration of the present invention, by using an antioxidant and talc in combination and adjusting the amount of each used, a solder resist film with excellent thermal shock resistance, high-temperature storage resistance, and acid resistance can be obtained while maintaining the good printability (covering ability, sagging) and stability (tin plating resistance, boil whitening resistance) of the alkaline developable resin composition.

[0019] In contrast, in the conventional technology, by using talc and barium sulfate together as fillers, acid resistance, tin plating resistance, and boil whitening resistance are improved, but printability, thermal shock resistance, and high-temperature storage stability are poor (for example, Patent Document 1, etc.).

[0020] As a result of intensive research by the present inventors, it has been found that talc, as a filler, has good flexibility, is excellent in crack resistance in a thermal cycle test (Temperature Cycle Test, hereinafter sometimes abbreviated as "TCT test"), and is excellent in high-temperature storage stability in a thermal shock test (Temperature shock Test, hereinafter sometimes abbreviated as "TS test"), but its acid resistance deteriorates as the usage amount increases. Barium sulfate, which is a conventional filler, can improve acid resistance, but has poor thermal shock resistance and high-temperature storage stability. Even when the usage amounts of both are increased simultaneously, high-temperature storage stability, acid resistance, and stability (tin plating resistance, boil whitening resistance) can be improved, but thermal shock resistance and printability (covering property, sagging) are still not good. On the other hand, by adding an antioxidant, acid resistance and stability (tin plating resistance, boil whitening resistance) can be improved without affecting printability. That is, by using an antioxidant and talc together, a surprising effect is achieved in that a solder resist film excellent in all of thermal shock resistance, high-temperature storage stability, acid resistance, tin plating resistance, and boil whitening resistance can be obtained while maintaining good printability (covering property, sagging), and the object of the present invention is achieved.

Advantages of the Invention

[0021] As described above, according to the present invention, it is possible to provide an alkaline-developable resin composition, a photocurable dry film thereof, a cured product thereof, and a printed wiring board that can form a solder resist film having good printability (covering property, sagging) and stability (tin plating resistance, boil whitening resistance) of the alkaline-developable resin composition and being excellent in all of thermal shock resistance and high-temperature storage stability.

Brief Description of the Drawings

[0022] [Figure 1] This photograph shows that cracks occurred in the solder resist film used to evaluate thermal shock resistance in the example. [Figure 2] This photograph shows that no cracks have occurred in the solder resist film used to evaluate thermal shock resistance in the example. [Figure 3] This photograph shows that no peeling occurred in the grid test used to evaluate high-temperature storage stability in the example. [Figure 4] This photograph shows the coating thickness of the alkaline developable resin composition on a copper corner for evaluating the covering properties in the examples. [Figure 5] This is an illustrative diagram showing how to measure the length of drip of the alkaline developable resin composition from the reference line in the example. [Modes for carrying out the invention]

[0023] The following describes each component of the alkaline-developable resin composition of the present invention.

[0024] The alkaline developable resin composition of the present invention contains (C) an antioxidant and (E) an inorganic filler, wherein the (E) inorganic filler contains talc, and when the total amount of the (E) inorganic filler is 100% by weight, the talc content is 50% by weight or more, and the total content of the inorganic filler is 60 to 180 parts by weight per 100 parts by weight (solids content) of the (A) vinyl ester resin. Therefore, first, (C) the antioxidant and (E) the inorganic filler will be described.

[0025] (C) Antioxidant The photosensitive resin composition of the present invention may contain antioxidants such as radical scavengers that eliminate generated radicals, and peroxide decomposers that decompose generated peroxides into harmless substances and prevent the generation of new radicals. The antioxidants used in the present invention can prevent oxidative degradation of resins and other materials, and can also suppress yellowing. Furthermore, if the inorganic filler contains talc, adding an antioxidant can significantly improve the acid resistance of the solder resist film and the stability of the ink (tin plating resistance, boil whitening resistance) in addition to the effects mentioned above. The antioxidant may be used alone or in combination of two or more types.

[0026] As the (C) antioxidant used in the alkaline developable resin composition of the present invention, an antioxidant that functions as a radical scavenger is preferred, as it is more advantageous in achieving the objectives of the present invention.

[0027] Examples of antioxidants that function as radical scavengers include hydroquinone, 4-tert-butylcatechol, 2-tert-butylhydroquinone, hydroquinone monomethyl ether, pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), 2,6-di-tert-butyl-p-cresol, 2,2-methylenebis(4-methyl-6-tert-butylphenol), and 1,1,3-tris(2-methyl-4-hydroxy-5-tert Examples include phenolic compounds such as -butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tri(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1,3,5-tris(3',5'-di-tert-butyl-4-hydroxybenzyl)-triazine-2,4,6-(1H,3H,5H)trione; quinone compounds such as p-methoxyphenol and benzoquinone; and amine compounds such as bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate and phenothiazine. Examples of commercially available products include ADEKASTAB AO-30, ADEKASTAB AO-330, ADEKASTAB AO-20, ADEKASTAB LA-77, ADEKASTAB LA-57, ADEKASTAB LA-67, ADEKASTAB LA-68, ADEKASTAB LA-87 (all manufactured by ADEKA CORPORATION, product names), IRGANOX 1010, IRGANOX 1035, IRGANOX 1076, IRGANOX 1135, TINUVIN 111FDL, TINUVIN 123, TINUVIN 144, TINUVIN 152, TINUVIN 292, TINUVIN 5100 (all manufactured by BASF JAPAN LTD., product names), and CHINOX TP-10H (manufactured by DOUBLE BOND CHEMICAL IND.CO.,LTD., product name).

[0028] Antioxidants that function as peroxide decomposition agents include, for example, phosphorus compounds such as triphenyl phosphite, sulfur compounds such as pentaerythritol tetrakis-(3-laurylthiopropionate), dilauryl thiodipropionate, and dioctadecyl 3,3'-thiodipropionate. Commercially available products include, for example, ADEKASTAB TPP (manufactured by ADEKA CORPORATION, trade name), MARK AO-412S (manufactured by ADEKA CORPORATION, trade name), and Sumilizer TPS (manufactured by Sumitomo Chemical Co., Ltd., trade name).

[0029] (C) The appropriate proportion of the antioxidant is 0.1 to 20 parts by weight, preferably 1 to 15 parts by weight, more preferably 3 to 12 parts by weight, and even more preferably 3 to 10 parts by weight, per 100 parts by weight (solid content) of the vinyl ester resin (A). If the amount of antioxidant used is within the above range, it is possible to ensure that the acid resistance of the solder resist film and the stability of the ink (tin plating resistance, boil whitening resistance) are significantly improved without adversely affecting printability.

[0030] (E) Inorganic filler As described above, in the alkaline-developable resin composition of the present invention, (E) talc used as an inorganic filler is used to improve thermal shock resistance and high-temperature storage performance.

[0031] As for the talc, the host rock can be any one of magnesium carbonate, serpentine, silica / silica-alumina, or magnesium deposits, or any of the so-called silicate minerals, and the shape can be massive or fine powder. Surface treatment may or may not be performed. The average particle size of the talc is appropriately 1.0 to 20.0 μm, more preferably 2.0 to 10 μm, and even more preferably 3.0 to 8.0 μm. Examples of commercially available products include HD25 manufactured by Pingdu City Talc Mining Co., Ltd. in Shandong Province, and LMP-100 manufactured by Fuji Talc Industry Co., Ltd. (E) When the inorganic filler consists only of talc, the printability is particularly excellent.

[0032] Talc can improve the printability of alkaline developable resin compositions and the thermal shock resistance and high-temperature storage properties of solder resist films, but its acid resistance deteriorates as the amount used increases. Therefore, in order to ensure the achievement of each effect of the present invention, it is appropriate, more preferably 55% by weight or more, and even more preferably 60% by weight or more, for the talc content when the total amount of (E) inorganic filler is 100% by weight.

[0033] Other fillers besides talc, such as barium sulfate, may be incorporated as long as they do not impair the objectives of the present invention. While the use of barium sulfate can improve acid resistance, increasing its amount adversely affects the printability (covering ability, sagging) and stability (tin plating resistance, boil whitening resistance) of the alkaline developable resin composition, as well as the thermal shock resistance and high-temperature storage ability of the solder resist film.

[0034] Examples of commercially available barium sulfate include B-30, B-31, B-32, B-33, B-34, B-35, and B-35T manufactured by Sakai Chemical Industry Co., Ltd.

[0035] Examples of inorganic filler shapes include spherical, needle-shaped, sheet-shaped, flaky, hollow, irregularly shaped, hexagonal, cubic, and flake-shaped.

[0036] The total content of inorganic fillers is appropriately 60 to 180 parts by weight, more preferably 80 to 160 parts by weight, and even more preferably 90 to 150 parts by weight, per 100 parts by weight (in terms of solid content) of (A) vinyl ester resin, in order to combine the printability of the alkaline developable resin composition, the thermal shock resistance of the solder resist film, and high-temperature storage properties.

[0037] (A) Vinyl ester resin In the photocurable thermosetting resin composition of the present invention, known resins having ethylenically unsaturated double bonds in their molecules can be used as the (A) vinyl ester resin from the viewpoint of photocurability and developability. Furthermore, to impart alkali developability, carboxyl group-containing resins having ethylenically unsaturated double bonds in their molecules are particularly preferred. Moreover, it is more preferable that the unsaturated double bond originates from acrylic acid or methacrylic acid or derivatives thereof. As the (A) vinyl ester resin, resins starting from epoxy resins, polyurethane resins having a urethane skeleton, copolymer resins having a copolymer structure of unsaturated carboxylic acids, and resins starting from phenolic compounds are preferred. Specific examples of (A) vinyl ester resins are shown below. (1) A vinyl ester resin obtained by copolymerizing an unsaturated carboxylic acid such as (meth)acrylic acid with one or more other compounds having an unsaturated double bond. (2) A photosensitive vinyl ester resin obtained by adding an ethylenically unsaturated group as a side group to a copolymer of an unsaturated carboxylic acid such as (meth)acrylic acid and one or more other compounds having an unsaturated double bond, using compounds having epoxy groups and unsaturated double bonds such as glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate, or (meth)acrylic acid chloride, etc. (3) A photosensitive vinyl ester resin obtained by reacting a copolymer of a compound having an epoxy group and an unsaturated double bond, such as glycidyl (meth)acrylate or 3,4-epoxycyclohexylmethyl (meth)acrylate, with an unsaturated carboxylic acid such as (meth)acrylic acid, and then reacting the resulting secondary hydroxyl group with a polybasic acid anhydride. (4) A photosensitive vinyl ester resin obtained by reacting a copolymer of an acid anhydride having an unsaturated double bond, such as maleic anhydride, with a compound having an unsaturated double bond, such as 2-hydroxyethyl (meth)acrylate, with a compound having a hydroxyl group and an unsaturated double bond. (5) A vinyl ester resin obtained by reacting a polyfunctional epoxy compound with an unsaturated monocarboxylic acid and reacting the resulting hydroxyl group with a saturated or unsaturated polybasic acid anhydride. (6) A vinyl ester resin containing hydroxyl groups and carboxyl groups is obtained by reacting a saturated or unsaturated polybasic acid anhydride with a hydroxyl group-containing polymer such as a polyvinyl alcohol derivative, and then reacting the resulting carboxylic acid with a compound having an epoxy group and an unsaturated double bond in one molecule. (7) A vinyl ester resin obtained by reacting a saturated or unsaturated polybasic acid anhydride with a reaction product of a polyfunctional epoxy compound, an unsaturated monocarboxylic acid, and a compound having at least one alcoholic hydroxyl group and one reactive group other than the alcoholic hydroxyl group that reacts with the epoxy group in one molecule, (8) A vinyl ester 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 resulting modified oxetane resin with a saturated or unsaturated polybasic acid anhydride, and (9) A vinyl ester resin obtained by reacting a polyfunctional epoxy resin with an unsaturated monocarboxylic acid, then reacting the carboxyl group-containing resin obtained by reacting it with a polybasic acid anhydride, and further reacting the carboxyl group-containing resin obtained by reacting it with a compound having one oxirane ring and one or more ethylenically unsaturated groups in the molecule. (10) A vinyl ester resin obtained by reacting an unsaturated monocarboxylic acid with a difunctional epoxy compound, and then reacting the resulting hydroxyl group with a saturated or unsaturated polybasic acid anhydride.

[0038] Of these examples, the vinyl ester resins described in (2), (5), (7), and (9) above are particularly preferred.

[0039] In this specification, (meth)acrylate is a general term referring to acrylate, methacrylate, and mixtures thereof, and the same applies to other similar expressions below.

[0040] The vinyl ester resin (A) described above has multiple free carboxyl groups in the side chains of the main chain polymer, and therefore can be developed using a dilute alkaline aqueous solution. In this specification, "polymer" is a general term encompassing homopolymers, copolymers, and mixtures thereof, and the same applies to other similar expressions.

[0041] Furthermore, the acid value of the vinyl ester resin (A) is preferably in the range of 40 to 200 mgKOH / g, and more preferably in the range of 45 to 120 mgKOH / g. If the acid value of the carboxyl group-containing resin is less than 40 mgKOH / g, alkaline development becomes difficult. On the other hand, if it exceeds 200 mgKOH / g, the dissolution of the exposed areas by the developer progresses, causing the lines to thin more than necessary, or in some cases, the exposed and unexposed areas to dissolve and peel off indiscriminately with the developer, making it difficult to draw a normal resist pattern, which is undesirable.

[0042] Furthermore, the weight-average molecular weight of the vinyl ester resin (A) described above varies depending on the resin skeleton, but is generally preferred to be in the range of 2,000 to 150,000, and even more preferably in the range of 5,000 to 100,000. If the weight-average molecular weight is less than 2,000, the tack-free performance after coating and drying on the substrate may be poor, and the moisture resistance of the coating film after exposure may be poor, resulting in film thinning during development and significantly reduced resolution. On the other hand, if the weight-average molecular weight exceeds 150,000, the developability may be significantly poor and the storage stability may be poor.

[0043] (A) The amount of vinyl ester resin added is preferably in the range of 20 to 60% by mass of the total composition in terms of solid content, and more preferably 25 to 50% by mass. (A) If the amount of vinyl ester resin added is less than the above range, the strength of the coating film will decrease, which is undesirable. On the other hand, if it is more than the above range, the viscosity of the composition will increase or the applicability will decrease, which is undesirable.

[0044] (B) Photopolymerization initiator The photopolymerization initiator used in the alkaline developable resin composition of the present invention is not particularly limited as long as it is a photopolymerization initiator commonly used in alkaline developable resin compositions.

[0045] Known photopolymerization initiators can be used, including benzoin, benzoin methyl ether and its alkyl ethers such as benzoin, benzoin ethyl ether; acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, and 4-(1-t-butyldioxy-1-methylethyl)acetophenone; and anthracones such as 2-methylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone, and 1-chloroanthraquinone. Examples include traquinones; thioxanthones such as isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, and 2,4-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone, 4-(1-t-butyldioxy-1-methylethyl)benzophenone, and 3,3',4,4'-tetrakis(t-butyldioxycarbonyl)benzophenone; and oxoanthracenes.

[0046] Furthermore, as photopolymerization initiators, oxime ester-based photopolymerization initiators having an oxime ester group, alkylphenone-based photopolymerization initiators, α-aminoacetophenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, titanocene-based photopolymerization initiators, phosphate ester-based photopolymerization initiators, etc., can also be used.

[0047] Commercially available oxime ester-based photopolymerization initiators include Irgacure OXE01 and Irgacure OXE02 from BASF Japan, and N-1919 and NCI-831 from ADEKA CORPORATION. Photopolymerization initiators having two oxime ester groups in the molecule can be suitably used, specifically oxime ester compounds having a carbazole structure.

[0048] Commercially available alkylphenone-based photopolymerization initiators include α-hydroxyalkylphenone-based products such as Omnirad 184, Omnirad 1173, Omnirad 2959, and Omnirad 127 from IGM Resins BV.

[0049] Examples of α-aminoacetophenone-based photopolymerization initiators include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, and N,N-dimethylaminoacetophenone. Commercially available products include Omnirad 907, Omnirad 369, and Omnirad 379 from IGM Resins BV.

[0050] Examples of acylphosphine oxide-based photopolymerization initiators include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and acylphosphine-based photopolymerization initiators with three or more functions. These acylphosphine-based photopolymerization initiators with three or more functions may be photopolymerization initiators having three or more acylphosphine oxide skeletons in one molecule, and can be represented by the following formula (I). JPEG2026077733000001.jpg28169In formula, A is independent of each other, consisting of single bonds, O, S, or NR. 3 This represents, G is a polyfunctional compound (core) G-(AH) m+n These are residues (where AH represents an alcohol group, an amino group, or a thiol group, respectively), Both m and n are integers, and m+n is an integer between 3 and 10. m is an integer between 3 and 8. R1 and R2 are each independently an unbroken C1-C alkyl group, an aryl group of C6-C, or a cycloalkyl group of C5-C, or are each independently interrupted by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino groups, or R1 and R2 are each independently a 5- to 6-membered heterocyclic group containing oxygen and / or nitrogen and / or sulfur atoms, which may be substituted with an aryl group, an alkyl group, an aryloxy group, an alkoxy group, a heteroatom and / or a heterocyclic group, 18 wherein the alkyl group of C1-C 12 the aryl group of C6-C 12 and the cycloalkyl group of C5-C. Alternatively, R1 and R2 may be each independently a 5- to 6-membered heterocyclic group containing oxygen and / or nitrogen and / or sulfur atoms, which may be substituted with an aryl group, an alkyl group, an aryloxy group, an alkoxy group, a heteroatom and / or a heterocyclic group, R2 may be R1-(C=O)-, Y is O or S, R3 is hydrogen or a C1-C4 alkyl group.

[0051] Here, the photoinitiator represented by formula (I) does not contain a photocurable ethylenically unsaturated group.

[0052] Preferably, in formula (I), m + n is an integer between 3 and 8, more preferably an integer between 3 and 6. For example, in formula I, m is an integer between 3 and 6, more preferably an integer between 3 and 5.

[0053] In formula (I), when A is oxygen, G-(A-H) m+n is a polyhydroxy compound, selected from the group consisting of monomer polyols, oligomer polyols, polymer polyols and mixtures thereof. When A is sulfur, G-(A-H) m+n is a polythiol compound. In formula (I), when A is nitrogen, G-(A-H) m+n is a linear or branched polyamine. When A is a mixture of oxygen and / or nitrogen and / or sulfur, G-(A-H) m+n is a compound containing different functional groups, for example, a compound containing an amino group and a hydroxy group. The residue G- suitable for the implementation of the present invention does not contain a photocurable ethylenically unsaturated group. When A is a single bond, G- is G-(A-H) exemplified above m+nThese are residues from which a hydroxyl group and / or an amino group and / or a mercapto group have been removed.

[0054] Preferably, G-(AH) m+n The number average molecular weight is 1,500 or less, more preferably 800 or less, and even more preferably 500 or less.

[0055] If n is not 0, the compound represented by formula (I) has an alcoholic free radical and / or an amino group and / or a mercapto group.

[0056] Table 1 shows representative acylphosphine-based photopolymerization initiators with three or more functions included in formula (I). Among these, PI-3, PI-4, PI-10, PI-11, PI-12, PI-14, and PI-17 are particularly preferred. By including such acylphosphine-based photopolymerization initiators with three or more functions, outgassing is suppressed, and a cured product with superior insulation reliability can be obtained.

[0057] [Table 1] JPEG2026077733000003.jpg227166JPEG2026077733000004.jpg238167JPEG2026077733000005.jpg185167 JPEG2026077733000006.jpg136167JPEG2026077733000007.jpg220167JPEG2026077733000008.jpg106165

[0058] Such trifunctional or more acylphosphine-based photopolymerization initiators can be produced, for example, by the method described in Japanese Patent No. 6599446.

[0059] Commercially available acylphosphine oxide-based photopolymerization initiators include Omnirad TPO from IGM Resins, Omnirad 819 and Omnipol TP from IGM Resins BV, etc.

[0060] Examples of the titanocene-based photopolymerization initiators include bis(cyclopentadienyl)(diphenyl)titanium(IV), bis(cyclopentadienyl)titanium(IV) dichloride, bis(cyclopentadienyl)-bis(2,3,4,5,6-pentafluorophenyl)titanium(IV), and bis(cyclopentadienyl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl)titanium(IV). A commercially available example is Omnirad 784 from IGM Resins BV.

[0061] The appropriate blending ratio of these photopolymerization initiators (B) is 0.01 to 30 parts by weight, preferably 5 to 25 parts by weight, and more preferably 10 to 20 parts by weight, per 100 parts by weight (in terms of solid content) of the vinyl ester resin (A). If the amount of photopolymerization initiator used is less than the above range, the photocurability of the composition will be poor, while if it is too much, the properties as a solder resist will be reduced, which is undesirable.

[0062] (D) Compounds having two or more ethylenically unsaturated groups in one molecule

[0063] The compound (D) having two or more ethylenically unsaturated groups in one molecule used in the alkaline-developable resin composition of the present invention is a compound that can be photocured by irradiation with active energy rays to insolubilize the vinyl ester resin (A) in an alkaline aqueous solution, or to assist in insolubilizing the vinyl ester resin in an alkaline aqueous solution. Specific examples of such compounds include: Hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate, Glycol monoacrylates or diacrylates such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol, Acrylamides such as N,N-dimethylacrylamide, N-methylolacrylamide, and N,N-dimethylaminopropylacrylamide, Aminoalkyl acrylates such as N,N-dimethylaminoethyl acrylate and N,N-dimethylaminopropyl acrylate, Polyols such as hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, tris(2-hydroxyethyl) isocyanurate, or polyvalent acrylates such as ethylene oxide adducts or propylene oxide adducts thereof, Phenoxyacrylate, bisphenol A diacrylate, and acrylates such as ethylene oxide adducts or propylene oxide adducts of these phenols, Glycidyl ether acrylates such as glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate, Examples include melamine acrylate and at least one of each of the methacrylates corresponding to the above acrylate.

[0064] Furthermore, examples include epoxy acrylate resins obtained by reacting a polyfunctional epoxy resin such as a cresol novolac type epoxy resin with acrylic acid, and epoxy urethane acrylate compounds obtained by reacting the hydroxyl groups of this epoxy acrylate resin with a half-urethane compound of a hydroxyacrylate such as pentaerythritol triacrylate and a diisocyanate such as isophorone diisocyanate.

[0065] The amount of compound (D) having two or more ethylenically unsaturated groups in one molecule is preferably 5 to 100 parts by weight, and more preferably 10 to 70 parts by weight, relative to 100 parts by weight (solid content) of the vinyl ester resin (A). If the amount of compound (D) is less than 5 parts by weight relative to 100 parts by weight of the vinyl ester resin (A), the photocurability of the resulting alkaline-developable resin composition decreases, making it difficult to form a pattern by alkaline development after irradiation with active energy rays, which is undesirable. On the other hand, if it exceeds 100 parts by weight, the solubility in alkaline aqueous solution decreases, and the cured coating film becomes brittle, which is also undesirable.

[0066] (F) Other additives As described above, the other additives in the present invention refer to additives other than (B) photopolymerization initiators and (C) antioxidants.

[0067] Examples of such additives include well-known and conventional colorants such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium dioxide, carbon black, and acid black; well-known and conventional thermal polymerization inhibitors such as fine silica, organic bentonite, and montmorillonite; at least one of silicone-based, fluorine-based, and polymer-based defoaming and leveling agents; adhesion promoters such as imidazole-based, thiazole-based, and triazole-based agents; silane coupling agents; and well-known and conventional light stabilizers such as hindered amine-based light stabilizers.

[0068] The appropriate proportion of such (F) other additives is 0.01% by weight or more and 20% by weight or less of the total amount of the alkaline developable resin composition. If it is less than 0.01% by weight, the effect will not be sufficiently obtained, while if it exceeds 20% by weight, the printability and hardness of the alkaline developable resin composition will deteriorate, which is undesirable.

[0069] (G) Epoxy resin To impart heat resistance, it is preferable to incorporate an epoxy resin having at least two epoxy groups in its molecule, i.e., a polyfunctional epoxy resin (G), into the alkaline developable resin composition used in the present invention.

[0070] Commercially available products include, for example, jER828, jER834, jER1001, jER1004 from Mitsubishi Chemical Corporation, EPICLON 840, 850, 850S, 1050, 2055 from DIC Corporation, EPOTOTE YD-011, YD-013, YD-127, YD-128 from NIPPON STEEL Chemical & Material Co., Ltd., DER317, DER331, DER661, DER664 from Dow Chemical Company, and Sumi-Epoxy ESA-011, ESA-014, ELA-115, ELA-128 from Sumitomo Chemical Co., Ltd. (all are product names) bisphenol A type epoxy resin; jERYL903 from Mitsubishi Chemical Corporation, EPICLON 152, EPICLON 165 from DIC Corporation, and NIPPON STEEL Chemical & Material Brominated epoxy resins such as EPOTOTE YDB-400, YDB-500 from Co., Ltd., DER542 from Dow Chemical Company, Sumi-Epoxy ESB-400, ESB-700 from Sumitomo Chemical Co., Ltd. (all are product names); jER152, jER154 from Mitsubishi Chemical Corporation, DEN431, DEN438 from Dow Chemical Company, EPICLON N-730, EPICLON N-770, EPICLON N-865 from DIC Corporation, EPOTOTE YDCN-701, YDCN-704 from NIPPON STEEL Chemical & Material Co., Ltd., EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306, NC-3000 from Nippon Kayaku Co., Ltd., and Sumi-Epoxy from Sumitomo Chemical Co., Ltd. ESCN-195X, ESCN-220, NIPPON STEEL Chemical & Novolac-type epoxy resins such as YDCN-700-2, YDCN-700-3, YDCN-700-5, YDCN-700-7, YDCN-700-10, YDCN-704, YDCN-704A from Material Co., Ltd., and EPICLON N-680, N-690, N-695 etc. (all product names) from DIC Corporation; EPICLON 830 from DIC Corporation, jER807 from Mitsubishi Chemical Corporation, and bisphenol F-type epoxy resins such as EPOTOTE YDF-170, YDF-175, YDF-2004 etc. (all product names) from NIPPON STEEL Chemical & Material Co., Ltd.; EPOTOTE Hydrogenated bisphenol A epoxy resins such as ST-2004, ST-2007, ST-3000 (product name), and YX8034 manufactured by Mitsubishi Chemical Corporation; jER604 manufactured by Mitsubishi Chemical Corporation; and NIPPON STEEL Chemical & Material Co., Ltd.Glycidylamine-type epoxy resins such as EPOTOTE YH-434 from [company name] and Sumi-Epoxy ELM-120 from Sumitomo Chemical Co., Ltd. (all trade names); hydantoin-type epoxy resins; alicyclic epoxy resins such as CELLOXIDE 2021P from Daicel Corporation (trade names); trihydroxyphenylmethane-type epoxy resins such as YL-933 from Mitsubishi Chemical Corporation and EPPN-501, EPPN-502 from Nippon Kayaku Co., Ltd. (all trade names); bixylenol-type or biphenol-type epoxy resins or mixtures thereof such as YL-6056, YX-4000, YL-6121 from Mitsubishi Chemical Corporation (all trade names); EBPS-200 from Nippon Kayaku Co., Ltd., ADEKA Bisphenol S type epoxy resins such as EPX-30 from CORPORATION and EXA-1514 (product name) from DIC Corporation; Bisphenol A novolac type epoxy resins such as jER157S (product name) from Mitsubishi Chemical Corporation; Tetraphenyloleethane type epoxy resins such as jERYL-931 (product name) from Mitsubishi Chemical Corporation; Heterocyclic epoxy resins such as TEPIC (product name) from Nissan Chemical Industries, Ltd.; Diglycidyl phthalate resins such as BRENMAR DGT from NOF Corporation; Tetraglycidyl xylenolethane resins such as ZX-1063 from NIPPON STEEL Chemical & Material Co., Ltd.; NIPPON STEEL Chemical & Material Co., Naphthalene skeleton-containing epoxy resins such as ESN-190 and ESN-360 from Ltd., and HP-4032, EXA-4750, and EXA-4700 from DIC Corporation; glycidyl methacrylate copolymer epoxy resins such as CP-50S and CP-50M from NOF Corporation; further, copolymer epoxy resins of cyclohexyl maleimide and glycidyl methacrylate; and CTBN-modified epoxy resins (e.g., NIPPON STEEL Chemical). Examples include, but are not limited to, YR-102, YR-450, etc., manufactured by & Material Co., Ltd. These epoxy resins may be used individually or in combination of two or more types.

[0071] (G) The epoxy resin content is preferably 10 to 100 parts by weight (in terms of solid content) per 100 parts by weight (A) of vinyl ester resin, more preferably 20 to 90 parts by weight, and even more preferably 30 to 80 parts by weight.

[0072] (H) Organic solvent Regarding the organic solvent (H) used in the alkaline developable resin composition of the present invention, (A) an organic solvent can be used for purposes such as the synthesis of vinyl ester resin, the preparation of the composition, or the adjustment of viscosity when coating it onto a substrate or carrier film.

[0073] Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, and petroleum-based solvents. More specifically, these include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, and propylene glycol butyl ether acetate; alcohols such as ethanol, propanol, ethylene glycol, and propylene glycol; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. The above organic solvents can be used individually or as mixtures of two or more.

[0074] When the alkaline developable resin composition of the present invention is used to form a solder resist film on a printed circuit board, the viscosity can be adjusted as needed to suit the application method, and then applied to a printed circuit board with pre-formed circuits, for example, by methods such as screen printing, curtain coating, spray coating, or roll coating. A tack-free coating can then be formed by drying it at a temperature of approximately 60 to 100°C, if necessary. Next, the coating can be selectively exposed to active light through a photomask with a predetermined exposure pattern, and the unexposed areas can be developed with an alkaline aqueous solution to form a resist pattern. Furthermore, by heating to a temperature of approximately 140 to 180°C to allow for thermal curing, the curing reaction of (G) epoxy resin and the polymerization of (A) vinyl ester resin can be promoted, improving the heat resistance, solvent resistance, acid resistance, moisture resistance, PCT resistance, adhesion, electrical properties, and other characteristics of the resulting resist film. The photocuring reaction may be further promoted by adding a UV irradiation step before or after thermal curing by heating.

[0075] As the alkaline aqueous solution used during the development process, alkaline aqueous solutions such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, and amines can be used. Furthermore, as the irradiation light source used for photocuring, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, semiconductor lasers, solid-state lasers, xenon lamps, or metal halide lamps are suitable. In addition to applying the alkaline developable resin composition of the present invention directly to a substrate having a copper circuit in liquid form, it can also be used in the form of a photocurable dry film obtained by pre-coating and drying the alkaline developable resin composition on a carrier film. The following describes how the alkaline developable resin composition of the present invention can be used as a photocurable dry film. A photocurable dry film has a structure in which a carrier film, a resin layer, and a peelable cover film, used as needed, are laminated in this order. The resin layer is obtained by applying the alkaline developable resin composition of the present invention to the carrier film and drying it. After forming the resin layer on the carrier film, a photocurable dry film is obtained by laminating the cover film on top of the resin layer. As the carrier film, a thermoplastic film such as polyester film with a thickness of 2 to 150 μm is used. The resin layer is formed by uniformly applying an alkaline developable resin composition to the carrier film to a thickness of 10 to 150 μm using a blade coater, lip coater, comma coater, film coater, etc., and then drying it. As the cover film, polyethylene film, polypropylene film, etc. can be used, but it is preferable that the adhesive strength to the resin layer is weaker than that of the carrier film. The cured product of the present invention is obtained by applying an alkaline developable resin composition to copper and drying it to obtain a coating film, or by applying the alkaline developable resin composition to a carrier film, drying it, and then laminating the resulting photocurable dry film onto copper to obtain a coating film, which is then photocured. To produce a cured product on a substrate with a copper circuit using a photocurable dry film, the cover film is peeled off, the resin layer and the substrate with the copper circuit are placed on top of each other, and they are bonded together using a laminator or the like to form a resin layer on the substrate with the copper circuit. The formed resin layer is then exposed, developed, and heat-cured in the same manner as described above to form a cured product. The carrier film can be peeled off either before or after exposure. Alkaline developable resin compositions are suitably used to form a cured film on printed circuit boards. The cured film is preferably a permanent insulating film, and particularly preferably a solder resist. Examples

[0076] The present invention will be described more specifically by examples and comparative examples, but the scope of rights and embodiments of the present invention are not limited thereto. Unless otherwise specified, "parts" or "%" in the examples and comparative examples are based on weight. The properties of the composition of this example will be tested by the method described later.

[0077] Synthesis example 214 parts of cresol novolac type epoxy resin EPICLON N-695 (manufactured by DIC, epoxy equivalent = 214) were added to a four-necked flask equipped with a stirrer and reflux condenser, along with 103 parts of diethylene glycol monoethyl ether acetate and a petroleum hydrocarbon solvent (manufactured by Japan Energy Corporation, trade name: Cactus Fines). 103 parts of SF-01) were added and heated to dissolve. Next, 0.1 parts of hydroquinone were added as a polymerization inhibitor and 2.0 parts of triphenylphosphine as a reaction catalyst. This mixture was heated to 95-105°C, and 72 parts of acrylic acid were slowly added dropwise, and the mixture was reacted for 16 hours. The resulting reaction product was cooled to 80-90°C, 91.2 parts of tetrahydrophthalic anhydride were added, and the mixture was reacted for 8 hours. After cooling, the product was removed. The carboxyl group-containing vinyl ester resin thus obtained had a non-volatile content of 65% and a solids acid value of 87.5 mgKOH / g.

[0078] Using the vinyl ester resin solution (varnish) from the above synthesis example, each component and proportion (parts by weight) shown in Table 1 were blended, pre-mixed with a stirrer, and then kneaded in a three-roll mill to prepare an alkaline developable resin composition. Furthermore, the thermal shock resistance (TCT test), high-temperature storage resistance (TS test), printability (covering ability, sagging), acid resistance, and stability (tin plating resistance, boil whitening resistance) were evaluated by the following methods.

[0079] [Table 1]

[0080] A example of synthesis: carboxyl group-containing vinyl ester resin, solids content 65%, (5) Equivalent to a vinyl ester resin containing a carboxyl group. F Pigment: Phthalocyanine Green, manufactured by Dainippon Ink and Chemicals, Inc. t A F. Antifoaming agent: KS-66, manufactured by Shin-Etsu Chemical Co., Ltd. C Antioxidant: IRGANOX 1010, manufactured by BASF JAPAN LTD. B Photoinitiator: Omnirad 369 E, manufactured by IGM E Talc: LMP-100, manufactured by FUJI TALC INDUSTRIAL. E. Barium sulfate: B-30, manufactured by Sakai Chemical Industry Co., Ltd. H Solvent: PGMEA, propylene glycol monomethyl ether acetate G Epoxy resin: N-770-75EA, manufactured by DIC Corporation, novolac type polyfunctional epoxy resin, solids content 75% D Compounds having two or more ethylenically unsaturated groups in one molecule: MT-3501G , made by Zhangjiagang Dongyadi Ai Biochemical Co., Ltd.

[0081] Performance evaluation (1) Thermal shock resistance (TCT test) The alkaline developable resin compositions of the examples and comparative examples were coated over the entire surface of a substrate on which a 2 mm copper wire pattern had been formed by screen printing, to a thickness of 40 μm, and dried in a hot air circulating drying oven at 80°C for 30 minutes. After cooling to room temperature, exposure was performed using an exposure apparatus equipped with a high-pressure mercury lamp at 400 mJ / cm². 2 Pattern exposure was performed, followed by development with a 1 wt% sodium carbonate aqueous solution at a pressure of 0.2 MPa and a liquid temperature of 30°C for 60 seconds. Then, it was cured in a hot air circulating drying oven at 150°C for 60 minutes. The cumulative exposure dose in the UV transport oven was 2000 mJ / cm². 2Seventeen evaluation substrates for crack resistance during thermal cycling, each with a right-angle resist pattern, were fabricated by irradiating them with ultraviolet light under the specified conditions. Multiple evaluation substrates fabricated in this manner were placed in a temperature cycling machine that performs thermal cycling from -40°C to 160°C, and thermal shock cycling (TCT) tests were conducted with different cycle counts. Next, the appearance was observed at each cycle count, and the number of cycles in which no cracks occurred was recorded (see Figures 1 and 2 for the presence or absence of cracks). The evaluation criteria are shown below. ○: No cracks appeared even after 1000 cycles. ×: Cracks occurred in less than 1000 cycles.

[0082] (2) High temperature storage capacity (TS test) The evaluation substrate described above was placed in a 160°C oven and left to stand for several different periods of time. A grid test was then performed as follows. The maximum number of hours during which no peeling occurred in the grid test was recorded. Grid pattern test: After irradiation with ultraviolet light in the UV transport furnace described above, a new cutter knife blade was applied to the board surface at a 30° angle to create a grid pattern of cuts on the surface of the solder resist film, and a peel test was performed using 3M tape (see Figure 3). ○: The high-temperature storage time during which no peeling occurred in the grid test exceeded 1000 hours. ×: The high-temperature storage time during which no peeling occurs in the grid test is less than 1000 hours.

[0083] (3) Coverability After printing the alkaline developable resin compositions shown in Table 1 onto copper circuits of a printed circuit board using screen printing, the coating status of the alkaline developable resin composition on individual circuits was observed, and the coating thickness of the alkaline developable resin composition on the copper corners was compared and evaluated. The thickness of the copper circuits was approximately 70 μm (see Figure 4). ○: The coating thickness of the alkaline developable resin composition is 10 μm or more. ×: The coating thickness of the alkaline developable resin composition is less than 10 μm.

[0084] (4) Hanging A starting line was drawn on a large copper-clad substrate with an oil-based pen. 0.2 ml of alkaline developable resin composition was drawn up using a 1 ml disposable syringe and applied to the copper-clad substrate. The large copper-clad substrate coated with the alkaline developable resin composition was placed upright in a substrate holder and baked in a hot air circulating dryer at 80°C for 30 minutes. After drying, the length of the drip from the reference line was measured (see Figure 5). ○: The length of the hanging part is 5 cm or less. ×: The length of the hanging part was longer than 5 cm.

[0085] (5) Acid resistance The alkaline developable resin compositions of the examples and comparative examples were coated over the entire surface of a substrate on which a 2 mm copper wire pattern had been formed by screen printing, to a thickness of 40 μm, and dried in a hot air circulating drying oven at 80°C for 30 minutes. After cooling to room temperature, exposure was performed using an exposure apparatus equipped with a high-pressure mercury lamp at 400 mJ / cm². 2 Pattern exposure was performed, and then the substrate was developed with a 1 wt% sodium carbonate aqueous solution at a pressure of 0.2 MPa and a liquid temperature of 30°C for 60 seconds. After that, it was cured in a hot air circulating drying oven at 150°C for 60 minutes to prepare an evaluation substrate with a solder resist film. This evaluation substrate was immersed in a 10 vol% H2SO4 aqueous solution at room temperature for 20 minutes, and the penetration between the solder resist film and the substrate and the dissolution of the solder resist film were visually confirmed, and peeling by tape peeling was also confirmed. ○: Items where no change is observed. △: Slightly altered. ×: Products with blistering or swelling and peeling of the coating.

[0086] (6) Tin plating resistance (solder heat resistance) The alkaline developable resin compositions of the examples and comparative examples were coated over the entire surface of a substrate on which a 2 mm copper wire pattern had been formed by screen printing, to a thickness of 40 μm, and dried in a hot air circulating drying oven at 80°C for 30 minutes. After cooling to room temperature, exposure was performed using an exposure apparatus equipped with a high-pressure mercury lamp at 400 mJ / cm². 2Pattern exposure was performed, and then the substrate was developed with a 1 wt% sodium carbonate aqueous solution at a pressure of 0.2 MPa and a liquid temperature of 30°C for 60 seconds. After that, it was cured in a hot air circulating drying oven at 150°C for 60 minutes to produce an evaluation substrate with a solder resist film. Rosin-based flux was applied to the solder resist film of this evaluation substrate. The evaluation substrate coated with rosin-based flux was immersed in a solder bath pre-set to 260°C, the flux was washed off with denatured alcohol, and then the blistering and peeling of the solder resist film were evaluated visually. The evaluation criteria are as follows. ○: No peeling was observed even after repeating immersion for 10 seconds three or more times. △: If you soak it for 10 seconds three or more times, it will peel off slightly. ×: Repeating immersion for 10 seconds three times or less may cause blistering and peeling of the solder resist film.

[0087] (7) Resistance to boiling and whitening The alkaline developable resin compositions of the examples and comparative examples were coated over the entire surface of a substrate on which a 2 mm copper wire pattern had been formed by screen printing, to a thickness of 40 μm, and dried in a hot air circulating drying oven at 80°C for 30 minutes. After cooling to room temperature, exposure was performed using an exposure apparatus equipped with a high-pressure mercury lamp at 400 mJ / cm². 2 Pattern exposure was performed, and then the substrate was developed with a 1 wt% sodium carbonate aqueous solution at a pressure of 0.2 MPa and a liquid temperature of 30°C for 60 seconds. After that, it was cured in a hot air circulating drying oven at 150°C for 60 minutes to produce an evaluation substrate with a solder resist film. Rosin-based flux was applied to the solder resist film of this evaluation substrate. The evaluation substrate coated with rosin-based flux was immersed in a solder bath pre-set to 288°C for 10 seconds, and then immersed in boiling water for 30 minutes to observe whether the surface color turned white or not. ○: It is not white. △: Slightly whitened. ×: It has become extremely pale.

[0088] As can be seen from the above, by adjusting the composition to that of Examples 1 to 4, an alkaline developable resin composition can be obtained that has good printability (covering ability, sagging) and stability (tin plating resistance, boil whitening resistance) of the alkaline developable resin composition, and can produce a solder resist film that is excellent in all aspects of thermal shock resistance, high-temperature storage ability, and acid resistance. In contrast, Comparative Example 1 used only barium sulfate as a filler without using talc, and Comparative Examples 2 and 3 had a low talc blending ratio in the filler, and none of them added an antioxidant, resulting in poor thermal shock resistance, high-temperature storage ability, and stability, as well as poor printability. In Comparative Example 4, as a result of increasing the talc blending ratio to 40 parts by weight, stability (tin plating resistance, boil whitening resistance) showed an improvement trend, but thermal shock resistance, high-temperature storage ability, and acid resistance were all poor, and printability was also poor. Comparative Example 5, in addition to Comparative Example 4, had an antioxidant added, resulting in improved acid resistance and stability (tin plating resistance, boil whitening resistance), but poor thermal shock resistance and high-temperature storage performance, and still poor printability. Comparative Example 6, in addition to Comparative Example 5, had an increased total amount of filler used, resulting in improved high-temperature storage performance, acid resistance, and stability (tin plating resistance, boil whitening resistance), and also improved some printability (dripping), but still poor thermal shock resistance and covering performance. Compared to Comparative Example 5, the reference example used only talc as a filler, resulting in excellent printability (covering performance, dripping), improved thermal shock resistance, high-temperature storage performance, and improved ink stability (tin plating resistance, boil whitening resistance), but poor acid resistance.

Claims

1. (A) vinyl ester resin, (B) photopolymerization initiator, (C) antioxidant, (D) compound having two or more ethylenically unsaturated groups in one molecule, and (E) inorganic filler, The (E) inorganic filler contains talc, When the total amount of the inorganic filler (E) is 100% by weight, the talc content is 50% by weight or more. The total content of the inorganic filler (E) is 60 to 180 parts by weight per 100 parts by weight (in terms of solid content) of the vinyl ester resin (A), The alkaline-developable resin composition is characterized in that the average particle size of the talc is 1.0 to 20.0 μm.

2. The alkaline developable resin composition according to claim 1, further comprising (F) other additives other than (B) the photopolymerization initiator and (C) the antioxidant.

3. (G) The alkaline developable resin composition according to claim 1, further comprising an epoxy resin.

4. (H) The alkaline developable resin composition according to claim 1, further comprising an organic solvent.

5. The alkaline developable resin composition according to any one of claims 1 to 4, characterized in that the content of (C) antioxidant is 3 parts by weight or more per 100 parts by weight (on a solid content basis) of the vinyl ester resin (A).

6. The alkaline developable resin composition according to any one of claims 1 to 4, characterized in that the (E) inorganic filler further comprises barium sulfate.

7. A photocurable dry film characterized by being obtained by applying an alkaline developable resin composition according to any one of claims 1 to 4 to a carrier film and drying it.

8. A cured product characterized by obtaining a coating film obtained by applying the alkaline developable resin composition described in any one of claims 1 to 4 to copper and drying it, or a coating film obtained by applying the alkaline developable resin composition to a carrier film, drying it, and laminating the resulting photocurable dry film onto copper, and then photocuring the coating film.

9. A printed circuit board characterized by having a coating film obtained by applying an alkaline developable resin composition according to any one of claims 1 to 4 to a substrate having a copper circuit and drying it, or a cured product obtained by photocuring the coating film obtained by applying the alkaline developable resin composition to a carrier film, drying it, and laminating the resulting photocurable dry film to a substrate having a copper circuit, and then thermocuring it.

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