Melamine-free photosensitive thermosetting developable two-component resin composition, dry film, cured product, and printed circuit board

Abstract

Provided are a melamine-free photosensitive thermosetting developable two-component resin composition of which a cured product has excellent acid resistance, metal plating resistance, high temperature storability, and discoloration resistance, and which reduces the volatilization of harmful substances in a welding stage and has an excellent drying control range; a dry film; a cured product; and a printed circuit board formed using the cured product. The melamine-free photosensitive thermosetting developable two-component resin composition comprises: (A) a carboxyl-containing vinyl ester resin, (B) a photopolymerization initiator, (C) melamine phthalate, and (D) an epoxy resin, wherein the carboxyl-containing vinyl ester resin (A) and the photopolymerization initiator (B) are contained in a first component, the epoxy resin (D) is contained in a second component different from the first component, and the content of the melamine phthalate (C) is 1.2-11.8 parts by weight with respect to 100 parts by weight of the carboxyl-containing vinyl ester resin (A) in terms of solid content.

Description

Melamine-free photosensitive thermosetting developable two-component resin composition, its dry film and cured product, and printed circuit board Technical Field

[0001] The present invention relates to a melamine-free, photosensitive and thermosetting two-component resin composition, a dry film thereof, and a cured product thereof. In particular, the present invention relates to a melamine-free, photosensitive and thermosetting two-component resin composition, a dry film thereof, and a cured product thereof, which are suitable for forming a solder resist for long-term reliable printed circuit boards. Background Art

[0002] Solder resist (also known as solder resist ink) has long been used as a protective material for printed circuit boards (PCBs). Currently, alkali-developable solder resists are used for some consumer PCBs and almost all industrial PCBs. These resists are developed after UV exposure to form an image and then fully cured (primary cure) by heat and / or light irradiation. Furthermore, solder resists designed for high-reliability electronic materials are trending toward long-term reliability in PCBs used in semiconductor devices for vehicles such as automobiles, trains, ships, and airplanes.

[0003] Currently available solder mask inks often contain melamine, which acts as a thermosetting agent and antioxidant to improve the ink's acid and alkali resistance, metal plating resistance, adhesion, and other properties. However, melamine in the ink also has many problems. It will volatilize during the soldering process (usually at 260°C), and according to the EU REACH regulation (Registration, Evaluation, Authorization and Restriction of Chemicals), melamine is classified as an SVHC (Substances of Very High Concern) environmentally controlled substance.

[0004] For example, the high-adhesion solder mask coating disclosed in Patent Document 1, the two-component solder mask photoresist disclosed in Patent Document 2, and the high-resolution solder mask ink disclosed in Patent Document 3 all use melamine. Patent Document 4 discloses a photosensitive solder mask ink that adds a melamine copolymer resin to the curing agent to improve the durability and corrosion resistance of the coating film. Patent Document 5 discloses a thermosetting ink that is resistant to yellowing and does not dry out by grafting modified melamine onto an epoxy resin. The modified melamine is dimethoxymelamine, trimethoxymelamine, tetramethylolmelamine, methylenemelamine, or methylated melamine.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: CN116239938A

[0008] Patent Document 2: CN116560187A

[0009] Patent Document 3: CN111100499A

[0010] Patent Document 4: CN114605867A

[0011] Patent Document 5: CN114656833A Summary of the Invention

[0012] Technical Problems to be Solved by the Invention

[0013] Traditionally, solder mask inks have typically contained melamine as a thermosetting agent and antioxidant. With increasingly stringent environmental regulations, there's a desire to reduce or eliminate the use of melamine. However, the present inventors have discovered that reducing the amount of melamine in existing solder mask inks (e.g., Patent Documents 1-3) can lead to a decrease in the solder mask's acid resistance and metal plating resistance after post-bake (i.e., post-curing). Furthermore, while prior art attempts have used melamine-derived resins as curing agents or curing components, these have failed to simultaneously meet the requirements for drying control range, acid resistance, metal plating resistance, high-temperature storage, and discoloration resistance. For example, Patent Document 4 uses a melamine copolymer resin, but due to its high molecular weight, it fails to impart sufficient thermosetting and antioxidant properties to the solder mask ink. Patent Document 5 uses trimethoxymelamine, which, due to its methoxy group, is highly reactive in thermosetting inks, but suffers from poor developability in developing inks, making it impractical.

[0014] Therefore, there is an urgent need to produce a developable resin composition with an excellent drying management range without using melamine, and the cured product thereof has excellent acid resistance, metal plating resistance (metallurgical resistance), high temperature storage ability, and discoloration resistance (i.e., it is not easy to undergo oxidative discoloration).

[0015] Therefore, an object of the present invention is to provide a melamine-free, photosensitive thermosetting, developable two-component resin composition whose cured product has excellent acid resistance, metal plating resistance, high-temperature storage stability, and discoloration resistance, reduces the volatilization of harmful substances during the soldering stage, and has an excellent drying control range.

[0016] Furthermore, the present invention aims to provide a dry film and a cured product having excellent properties as described above, obtained using such a melamine-free photosensitive and thermosetting two-component resin composition, and a printed wiring board formed by forming a cured coating such as a solder resist using such a melamine-free photosensitive and thermosetting two-component resin composition, its dry film, or its cured product.

[0017] Solutions for solving problems

[0018] The present inventors have conducted extensive research to address the aforementioned issues and have discovered that, when melamine phthalate is used in a specific amount as a curing agent and antioxidant in place of melamine in a photosensitive thermosetting and developable two-component resin composition, melamine phthalate, due to its unique structure, does not volatilize during the soldering process and has antioxidant properties comparable to those of melamine. The resulting melamine-free photosensitive thermosetting and developable two-component resin composition exhibits substantially the same other properties when used in solder resist inks.

[0019] Based on this, the present inventors have discovered that the above-mentioned problems can be solved by the following melamine-free photosensitive thermosetting and developable two-component resin composition, thereby completing the present invention. The melamine-free photosensitive thermosetting and developable two-component resin composition is characterized in that it comprises (A) a carboxyl vinyl ester resin, (B) a photopolymerization initiator, (C) a melamine phthalate, and (D) an epoxy resin, wherein the (A) carboxyl vinyl ester resin and the (B) photopolymerization initiator are contained in a first component, and the (D) epoxy resin is contained in a second component different from the first component, and the (C) melamine phthalate is contained in an amount of 1.2 to 11.8 parts by weight per 100 parts by weight of the (A) carboxyl vinyl ester resin on a solids basis.

[0020] As a preferred embodiment of the present invention, in the melamine-free photosensitive thermosetting and developable two-component resin composition, the amount of the melamine phthalate (C) is 1.8 to 18.2 parts by weight relative to 100 parts by weight of the epoxy resin (D) in terms of solid content.

[0021] As a preferred embodiment of the present invention, the above-mentioned (C) melamine phthalate is contained in the first component.

[0022] As a preferred embodiment of the present invention, the melamine-free photosensitive thermosetting and developable two-component resin composition further contains (E) an inorganic filler.

[0023] As a more preferred embodiment of the present invention, in the melamine-free photosensitive thermosetting and developable two-component resin composition, the (E) inorganic filler is contained in the first component.

[0024] In a preferred embodiment of the present invention, the melamine-free photosensitive thermosetting and developable two-component resin composition further contains (F) a photosensitive monomer.

[0025] As a more preferred embodiment of the present invention, in the melamine-free photosensitive thermosetting and developable two-component resin composition, the (F) photosensitive monomer is contained in the second component.

[0026] As a preferred embodiment of the present invention, in the above-mentioned melamine-free photosensitive thermosetting and developable two-component resin composition, the first component and / or the second component further contains (G) an organic solvent.

[0027] Another embodiment of the present invention relates to a dry film comprising a carrier film and a resin layer obtained by applying the melamine-free photosensitive thermosetting and developable two-component resin composition on the carrier film and drying the coating.

[0028] Still another embodiment of the present invention relates to the melamine-free photosensitive thermosetting and developable two-component resin composition, characterized in that the composition is used for a solder resist.

[0029] Still another embodiment of the present invention relates to a cured product characterized in that it is obtained by curing the above-mentioned melamine-free photosensitive thermosetting and developable two-component resin composition.

[0030] Still another aspect of the present invention relates to a cured product characterized by being obtained by curing the resin layer of the dry film.

[0031] Still another aspect of the present invention relates to a printed wiring board comprising the above-mentioned cured product.

[0032] Effects of the Invention

[0033] As described above, the present invention can provide a melamine-free, photosensitive, thermosetting, developable two-component resin composition, a dry film thereof, a cured product thereof, and a printed circuit board, the cured product of which has excellent acid resistance, metal plating resistance, high-temperature storage stability, and discoloration resistance, reduces the volatilization of harmful substances during the soldering stage, and has an excellent drying control range. DETAILED DESCRIPTION

[0034] Hereinafter, the melamine-free photosensitive thermosetting and developable two-component resin composition of the present invention will be described.

[0035] The melamine-free photosensitive thermosetting developable two-component resin composition of the present invention (hereinafter sometimes referred to as "photosensitive thermosetting developable two-component resin composition", "two-component resin composition" or "composition") comprises (A) a carboxyl vinyl ester resin, (B) a photopolymerization initiator, (C) melamine phthalate, and (D) an epoxy resin, wherein the (A) carboxyl vinyl ester resin and the (B) photopolymerization initiator are contained in a first component, and the (D) epoxy resin is contained in a second component different from the first component. The amount of the (C) melamine phthalate is 1.2 to 11.8 parts by weight per 100 parts by weight of the (A) carboxyl vinyl ester resin in terms of solid content.

[0036] The melamine-free, photosensitive, thermosetting, developable two-component resin composition of the present invention comprises a first component and a second component different from the first component. "Two-component" herein means comprising at least a two-component system. Therefore, in addition to the first and second components, the two-component resin composition of the present invention may further comprise other components, such as a third component.

[0037] Examples of two-component systems include one resin composition serving as a base composition and another resin composition serving as a curing agent composition. In two-component resin compositions, the different components, such as the base composition and the curing agent composition, are mixed immediately before use. During preparation, storage, and transportation, the different components are kept separate and isolated from each other to prevent mixing and reaction.

[0038] In the present invention, the first component containing (A) the carboxyl vinyl ester resin and (B) the photopolymerization initiator can be considered the base composition, while the second component containing (D) the epoxy resin can be considered the curing agent composition. Therefore, in the two-component resin composition of the present invention, to avoid a reaction between the base and curing agent during storage that could impair the performance of the solder resist ink, it is preferred that the first component not contain (D) the epoxy resin, and the second component not contain (A) the carboxyl vinyl ester resin and (B) the photopolymerization initiator.

[0039] Hereinafter, each component contained in the melamine-free photosensitive thermosetting and developable two-component resin composition of the present invention will be described.

[0040] (A) Carboxyl vinyl ester resin

[0041] The first component of the two-component resin composition of the present invention comprises (A) a carboxyl vinyl ester resin. The carboxyl vinyl ester resin (A) used in the present invention is particularly preferably one having an ethylenically unsaturated double bond in its molecule, as it can impart alkali developability, photocurability, and developer resistance. Examples include resins starting from epoxy resins, polyurethane resins having a urethane backbone, copolymeric resins having a copolymeric structure of unsaturated carboxylic acids, and resins starting from phenolic compounds. Specific examples of carboxyl vinyl ester resins are shown below.

[0042] (1) A carboxyl group-containing vinyl ester resin obtained by reacting a reaction product of a polyfunctional epoxy compound and an unsaturated monocarboxylic acid with a compound having at least one alcoholic hydroxyl group and one reactive group other than the alcoholic hydroxyl group that reacts with an epoxy group in one molecule, with a saturated or unsaturated polybasic acid anhydride;

[0043] (2) a carboxyl-containing vinyl ester resin obtained by reacting an unsaturated monocarboxylic acid with a polyfunctional epoxy resin and then reacting it with a polyacid anhydride, and further reacting the resultant carboxyl-containing resin with a compound having one oxirane ring and one or more ethylenically unsaturated groups in the molecule;

[0044] (3) Carboxyl group-containing vinyl ester resins obtained by reacting a polyfunctional epoxy resin such as a phenol novolac epoxy resin, a cresol novolac epoxy resin, a bisphenol A cresol novolac epoxy resin, or a dicyclopentadiene cresol novolac epoxy resin with (meth)acrylic acid, and adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the hydroxyl groups present in the side chains;

[0045] (4) reacting the multifunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of the multifunctional epoxy resin in (3) with epichlorohydrin with (meth)acrylic acid, and adding a polybasic acid anhydride to the generated hydroxyl groups to obtain a carboxyl group-containing vinyl ester resin;

[0046] (5) Carboxyl group-containing vinyl ester resins obtained by adding cyclic ethers such as ethylene oxide or cyclic carbonates such as propylene carbonate to polyfunctional phenolic compounds such as novolac resins, partially esterifying the resulting hydroxyl groups with (meth)acrylic acid, and reacting the remaining hydroxyl groups with polyacid anhydrides;

[0047] (6) Carboxyl group-containing vinyl ester resins obtained by further adding a compound having one epoxy group and one or more (meth)acryloyl groups in the molecule, such as glycidyl (meth)acrylate or α-methylglycidyl (meth)acrylate, to any of the resins described in (3) to (5).

[0048] Particularly preferred among these examples are cresol novolac type and phenol novolac type carboxyl group-containing vinyl ester resins, namely the carboxyl group-containing vinyl ester resins (3), (4), (5), and (6) described above.

[0049] It should be noted that, in this specification, (meth)acrylate is a term that collectively refers to acrylate, methacrylate, and a mixture thereof, and the same applies to other similar expressions.

[0050] Since the carboxyl group-containing vinyl ester resin (A) described above has a plurality of free carboxyl groups on the side chains of the main chain polymer, it can be developed with a dilute alkaline aqueous solution.

[0051] The acid value of the carboxyl group-containing vinyl ester resin (A) is preferably in the range of 40 to 200 mgKOH / g, more preferably in the range of 45 to 120 mgKOH / g. An acid value of less than 40 mgKOH / g makes alkali development difficult, while an acid value exceeding 200 mgKOH / g promotes dissolution of the exposed portion by the developer, resulting in thinner lines than desired. In some cases, the exposed and unexposed portions are dissolved and peeled off indiscriminately by the developer, making it difficult to form a normal resist pattern. This is not preferred.

[0052] The weight-average molecular weight of the carboxyl group-containing vinyl ester resin (A) varies depending on the resin backbone, but is generally preferably in the range of 2,000 to 150,000, more preferably 5,000 to 100,000. A weight-average molecular weight of less than 2,000 may result in poor application to a substrate and dryness (tack-free properties) after drying. Furthermore, the moisture resistance of the coating film after exposure may deteriorate, film loss may occur during development, and resolution may be significantly reduced. On the other hand, a weight-average molecular weight exceeding 150,000 may result in significantly poor developability and poor storage stability.

[0053] The amount of the carboxyl group-containing vinyl ester resin (A) added is preferably in the range of 20 to 60% by mass, and preferably 25 to 50% by mass, based on the solid content of the entire composition. If the amount of the carboxyl group-containing vinyl ester resin (A) added is less than the above range, the coating film strength is reduced, which is not preferred. On the other hand, if the amount is greater than the above range, the viscosity of the composition increases, or the coating properties are reduced, which is not preferred.

[0054] (B) Photopolymerization initiator

[0055] The first component of the photosensitive thermosetting and developable two-component resin composition of the present invention comprises (B) a photopolymerization initiator. Any photopolymerization initiator commonly used in photosensitive thermosetting and developable resin compositions can be used without particular limitation.

[0056] As the (B) photopolymerization initiator, a known substance can be used, for example, bisacylphosphine oxides such as bis(2,6-dichlorobenzoyl)phenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; bis(2,6-dimethoxybenzoyl)phenylphosphine oxide; Monoacylphosphine oxides such as diphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine oxide, methyl 2,4,6-trimethylbenzoylphenylphosphine oxide, 2-methylbenzoyldiphenylphosphine oxide, isopropyl pivaloylphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide; 1-hydroxy-cyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propane-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1-one, etc. Benzoin, benzil, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether and other benzoins; benzoin alkyl ethers; benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone and other benzophenones; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)- Acetophenones such as 2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone and N,N-dimethylaminoacetophenone; thioxanthones such as 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone and 2,4-diisopropylthioxanthone; anthraquinones such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone and 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzil dimethyl ketal; benzoic acid esters such as ethyl 4-dimethylamino benzoate, 2-(dimethylamino)ethyl benzoate and ethyl p-dimethylbenzoate;Oxime esters such as 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime) and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-ethanone 1-(O-acetooxime); titanocenes such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium and bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyrrol-1-yl)ethyl)phenyl]titanium; 2-nitrofluorene phenyl disulfide, butyroin, anisoin ethyl ether, azobisisobutyronitrile, and tetramethylthiuram disulfide. (B) Photopolymerization initiators may be used alone or in combination of two or more.

[0057] Examples of commercially available photopolymerization initiators (B) include oxime esters such as Irgacure OXE01 and Irgacure OXE02 manufactured by BASF Japan, and N-1919 and NCI-831 manufactured by ADEKA CORPORATION; α-hydroxyalkyl phenones such as Omnirad 184, Omnirad 1173, Omnirad 2959, and Omnirad 127 manufactured by IGM Resins BV; acetophenones such as Omnirad 907, Omnirad 369, and Omnirad 379 manufactured by IGM Resins BV; acylphosphine oxides such as Omnirad TPO manufactured by IGM Resins, Ltcure TMO manufactured by Shanghai Feikai Materials Technology Co., Ltd., and Omnirad 819 and Omnipol TP manufactured by IGM Resins BV; and Omnirad 784 and other titanocenes manufactured by BV.

[0058] The compounding ratio of the photopolymerization initiator (B) is preferably 0.01 to 30 parts by weight, preferably 5 to 25 parts by weight, and more preferably 10 to 20 parts by weight, relative to 100 parts by weight of the carboxyl group-containing vinyl ester resin (A) as a solid content. If the amount of the photopolymerization initiator (B) used is less than this range, the photocurability of the composition deteriorates. On the other hand, if the amount is too high, the solder resist properties of the two-component resin composition of the present invention are degraded, which is not preferred.

[0059] (C) Melamine Phthalate

[0060] The photosensitive thermosetting developable two-component resin composition of the present invention contains (C) melamine phthalate. The melamine phthalate (C) may be contained in either the first component or the second component, but is preferably contained in the first component, that is, in the main agent composition.

[0061] The present inventors compared the weight loss (i.e., volatile matter weight) of photosensitive, thermosetting, developable, two-component resin compositions containing melamine and melamine phthalate after thermal curing. They found that the composition containing melamine phthalate had significantly less volatile matter than the composition containing melamine. Furthermore, the composition containing melamine phthalate achieved comparable drying control ranges, high-temperature storage stability, discoloration resistance, acid resistance, and metal plating resistance of its cured product. While the underlying mechanism has not yet been fully elucidated, the present inventors speculate as follows. On the one hand, melamine phthalate contains melamine in its structure, thus acting as a curing agent and antioxidant, similar to melamine. In other words, melamine phthalate prevents oxidation of the copper circuitry, thereby improving the adhesion between the substrate containing the copper circuitry and the cured product. Consequently, acid resistance, metal plating resistance, and high-temperature storage performance are improved. Furthermore, melamine phthalate inhibits discoloration of the copper circuitry that serves as the base of the cured product, thereby improving the cured product's discoloration resistance. Furthermore, due to its unique structure, melamine phthalate remains relatively stable in the composition during soldering, typically performed at 260°C, and is less likely to volatilize in large quantities than melamine. Therefore, using melamine phthalate instead of melamine can reduce the volatilization of harmful substances during soldering without affecting the composition's performance.

[0062] The blending ratio of the melamine phthalate (C) is 1.2 to 11.8 parts by weight, preferably 1.8 to 10.2 parts by weight, per 100 parts by weight of the carboxyl group-containing vinyl ester resin (A), calculated as a solid content. If the amount of the melamine phthalate (C) used is less than 1.2 parts by weight, the curing agent and antioxidant functions are not effectively exerted, resulting in a cured product with good discoloration resistance. The composition also tends to have insufficient acid resistance, high-temperature storage properties, and metal plating resistance. If the amount of the melamine phthalate (C) used exceeds 11.8 parts by weight, the composition's drying range is poor, and volatile matter emissions during soldering significantly increase.

[0063] (D) Epoxy resin

[0064] The second component in the photosensitive and thermosetting two-component resin composition of the present invention comprises an epoxy resin (D). The epoxy resin (D) functions as a thermosetting component in the photosensitive and thermosetting two-component resin composition of the present invention to form a cured product.

[0065] As such an epoxy resin, a well-known and commonly used multifunctional epoxy resin having at least two epoxy groups in one molecule can be used.

[0066] The epoxy resin (D) used in the present invention may be liquid at room temperature, or may be solid or semisolid.

[0067] As the multifunctional epoxy resin, preferably bisphenol A type epoxy resin; brominated epoxy resin; novolac type epoxy resin; bisphenol F type epoxy resin; hydrogenated bisphenol A type epoxy resin; glycidylamine type epoxy resin; hydantoin type epoxy resin; alicyclic epoxy resin; trishydroxyphenylmethane type epoxy resin; bixylenol type or biphenol type epoxy resin or a mixture thereof; bisphenol S type epoxy resin; bisphenol A novolac type epoxy resin; tetrahydroxyphenylethane type epoxy resin; Resins; heterocyclic epoxy resins; diglycidyl phthalate resins; tetraglycidyl ditoluoylethane resins; naphthyl-containing epoxy resins; epoxy resins having a dicyclopentadiene skeleton; glycidyl methacrylate copolymerized epoxy resins; cyclohexylmaleimide and glycidyl methacrylate copolymerized epoxy resins; epoxy-modified polybutadiene rubber derivatives; CTBN-modified epoxy resins; epoxy resins having an isocyanurate ring, etc., but are of course not limited to these. These epoxy resins can be used alone or in combination of two or more.

[0068] The epoxy resins that are solid or semi-solid at room temperature can also be known and commonly used. For example, as epoxy resins that are solid at room temperature, bisphenol A epoxy resin (jER1001 manufactured by Mitsubishi Chemical Corporation), bisphenol F epoxy resin (jER4004P manufactured by Mitsubishi Chemical Corporation), naphthalene epoxy resin (HP-4700 manufactured by DIC Corporation), polyfunctional solid epoxy resin containing a naphthalene skeleton (NC-7000 manufactured by Nippon Kayaku Co., Ltd.), trisphenol epoxy resin (EPPN-502H manufactured by Nippon Kayaku Co., Ltd.), polyfunctional solid epoxy resin containing a dicyclopentadiene skeleton (Epiclon manufactured by DIC Corporation), HP-7200, HP-7200H), phosphorus-containing epoxy resin (TX0712 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), tris(2,3-epoxypropyl)isocyanurate (TEPIC manufactured by Nissan Chemical Industries, Ltd.), and epoxy resins that are semi-solid at room temperature include bisphenol A type epoxy resin (jER834 manufactured by Mitsubishi Chemical Corporation), naphthalene type epoxy resins (HP-4032, EXA-4750, EXA-4700 manufactured by DIC Corporation, ESN-190, ESN-360 manufactured by NIPPON STEEL Chemical & Material Co., Ltd.), etc.

[0069] Here, in the present invention, being solid or semi-solid at room temperature means being solid or semi-solid at 15° C. Determination of solid or semi-solid can be made in accordance with Annex 2, "Method for Confirming Liquid State," of the Ministerial Ordinance concerning the Test and Properties of Dangerous Substances (Ministry of Home Affairs Ordinance No. 1 of 1991).

[0070] As the biphenyl-type epoxy resin, a well-known and commonly used multifunctional epoxy resin having a biphenyl skeleton can be used. Examples thereof include multifunctional solid epoxy resins containing a biphenyl skeleton (NC-3000H and NC-3000 manufactured by Nippon Kayaku Co., Ltd.) and biphenyl-type epoxy resins (YX-4000 and YL-6121HA manufactured by Mitsubishi Chemical Corporation).

[0071] Examples of the novolac epoxy resin include cresol novolac epoxy resin (Epiclon N-690 manufactured by DIC Corporation), phenol novolac epoxy resin (Epiclon N-770 manufactured by DIC Corporation, jER152 manufactured by Mitsubishi Chemical Corporation), and the like.

[0072] The content of the epoxy resin (D) described above is preferably approximately 30 to 100 parts by weight, more preferably 40 to 90 parts by weight, and even more preferably 50 to 85 parts by weight, based on 100 parts by weight of the carboxyl group-containing vinyl ester resin (A) as a solid component.

[0073] From the perspective of further exerting the effects of the present invention, such as improved discoloration resistance and reduced volatilization of harmful substances during the soldering stage, the amount of the melamine phthalate (C) is preferably 1.8 to 18.2 parts by weight, more preferably 2.3 to 16.9 parts by weight, and even more preferably 3.0 to 16.0 parts by weight, relative to 100 parts by weight of the epoxy resin (D) in terms of solid content.

[0074] (E) Inorganic fillers

[0075] The melamine-free photosensitive thermosetting and developable two-component resin composition of the present invention may contain (E) an inorganic filler. The (E) inorganic filler may be used alone or in combination of two or more.

[0076] Examples of the inorganic filler (E) include titanium oxide, silica, barium sulfate, barium titanate, Neuburg silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, and aluminum nitride. Among these, the inclusion of at least one of talc, silica, and barium sulfate is preferred, as it can suppress cure shrinkage of the cured product of the photosensitive thermosetting and developable two-component resin composition and improve properties such as adhesion, hardness, and gloss.

[0077] From the perspective of improving the mechanical properties, high-temperature storage resistance, processability, and chemical resistance of the cured product, the inorganic filler (E) is preferably included in the main component, that is, in the first component of the two-component resin composition of the present invention. In this case, the inorganic filler (E) is preferably at least one of silica and barium sulfate.

[0078] (E) The inorganic filler may be surface-treated and used. More preferably, the surface of the inorganic filler is surface-treated to introduce curable reactive groups.

[0079] Here, the curable reactive group refers to a group that undergoes a curing reaction with (A) the carboxyl group-containing vinyl ester resin, (E) the epoxy resin, or the like, and may be a photocurable reactive group or a thermosetting reactive group. Examples of the photocurable reactive group include methacryloyl, acryloyl, vinyl, and styryl groups, while examples of the thermosetting reactive group include epoxy, amino, hydroxyl, carboxyl, isocyanate, imino, oxetanyl, mercapto, methoxymethyl, methoxyethyl, ethoxymethyl, ethoxyethyl, and oxazoline groups.

[0080] The method for introducing curable reactive groups into the surface of the inorganic filler is not particularly limited, and can be introduced using a known conventional method. The surface of the inorganic filler can be treated with a surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group as an organic group. As coupling agents, silane coupling agents, titanium coupling agents, zirconium coupling agents, aluminum coupling agents, etc. can be used. It should be noted that, as inorganic fillers without a surface treatment having a curable reactive group, for example, silica-alumina surface treatment, titanate coupling agent treatment, aluminate coupling agent treatment, organically treated inorganic fillers, etc. can be cited.

[0081] (E) The shape of the inorganic filler may be spherical, needle-like, flake-like, scaly, hollow, irregular, hexagonal, cubic, or flake-like. From the viewpoint of high filling of the inorganic filler, a spherical shape is preferred.

[0082] The average particle size (D50) of the (E) inorganic filler is 2000 nm or less, more preferably 1200 nm or less. The lower limit thereof is preferably 0.1 nm or more in terms of the average particle size (D50).

[0083] (E) The smaller the average particle size of the inorganic filler, the more diffuse reflection during light irradiation is suppressed, and the micro-processing of the cured product pattern can be facilitated. The average particle size (D50) can be obtained using a laser diffraction particle size distribution measuring device and a measuring device based on a dynamic light scattering method. As a measuring device based on a laser diffraction method, MicrotracMT3300EXII manufactured by MicrotracBEL Inc. can be cited, and as a measuring device based on a dynamic light scattering method, Nanotrac Wave II UT151 manufactured by MicrotracBEL Inc. can be cited.

[0084] The amount of the inorganic filler (E) is preferably in the range of 20 to 240 parts by weight, more preferably 50 to 200 parts by weight, and even more preferably 80 to 160 parts by weight, relative to 100 parts by weight of the carboxyl group-containing vinyl ester resin (A) as a solid component. When the inorganic filler is present in an amount of 20 parts by weight or more, a cured film having superior acid resistance, metal plating resistance, and discoloration resistance tends to be obtained. When the inorganic filler is present in an amount of 240 parts by weight or less, a photosensitive thermosetting and developable two-component resin composition having superior degassing properties, resolution, and deep curing properties tends to be obtained.

[0085] (F) Photosensitive monomer

[0086] The melamine-free photosensitive thermosetting and developable two-component resin composition of the present invention may contain (F) a photosensitive monomer. The (F) photosensitive monomer may be used alone or in combination of two or more.

[0087] The photosensitive monomer (F) in the present invention is not particularly limited, and commonly known photosensitive monomers can be used. The photosensitive monomer (F) can be, for example, a compound having one or more ethylenically unsaturated groups in its molecule. Such a photosensitive monomer contributes to the photocuring of the carboxyl vinyl ester resin (A) upon irradiation with active energy rays (if it contains an ethylenically unsaturated group), thereby curing the photosensitive thermosetting and developable two-component resin composition.

[0088] From the viewpoint of avoiding a reaction during storage that would impair the performance of the solder resist ink, the (F) photosensitive monomer is preferably contained in the curing agent, that is, in the second component of the two-component resin composition of the present invention.

[0089] (F) The photosensitive monomer preferably used in the present invention includes, for example, methyl α-(allyloxymethyl)acrylate, or diol diacrylates such as 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, and 1,10-decanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, Tripropylene glycol diacrylate, polypropylene glycol diacrylate, neopentyl glycol diacrylate, diol diacrylates obtained by adding at least one of ethylene oxide and propylene oxide to neopentyl glycol, diol diacrylates such as caprolactone-modified hydroxypivalate neopentyl glycol diacrylate, bisphenol A EO adduct diacrylate, bisphenol A PO adduct diacrylate, tricyclodecane dimethanol diacrylate, hydrogenated dicyclopentadienyl diacrylate, cyclohexyl diacrylate esters, or bifunctional (meth)acrylates such as methacrylate monomers corresponding thereto, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolmethane triacrylate, ethylene oxide-modified trimethylolpropane triacrylate, propylene oxide-modified trimethylolpropane triacrylate, epichlorohydrin-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, tetramethylolmethane tetraacrylate, ethylene oxide-modified phosphoric acid triacrylate, epichlorohydrin-modified glycerol triacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, or polyfunctional acrylates such as silsesquioxane-modified products thereof, or methacrylate monomers corresponding thereto, trifunctional methacrylates, polyfunctional (meth)acrylates such as ε-caprolactone-modified tris(acryloyloxyethyl)isocyanurate, or combinations of two or more thereof.

[0090] The content of the photosensitive monomer (F) is preferably 5 to 90 parts by weight, more preferably 20 to 60 parts by weight, and even more preferably 30 to 50 parts by weight, based on 100 parts by weight of the carboxyl group-containing vinyl ester resin (A) as a solid component.

[0091] When the content of the photosensitive monomer (F) is within this range, the melamine-free photosensitive thermosetting and developable two-component resin composition has sufficient photocurability, patterning during development is improved, and dryness to touch is also improved.

[0092] (G) Organic solvents

[0093] In the melamine-free photosensitive thermosetting developable two-component resin composition of the present invention, in order to synthesize the aforementioned (A) carboxyl vinyl ester resin, prepare the various components in the composition, or adjust the viscosity of the entire composition obtained by mixing the various components for coating on a substrate or a carrier film, an (G) organic solvent may be used in at least one component.

[0094] Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, and petroleum solvents. More specifically, they 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 solvents such as petroleum ether, naphtha, hydrogenated naphtha, and solvent naphtha. The above organic solvents may be used alone or in the form of a mixture of two or more.

[0095] The content of the organic solvent (G) is preferably 30 to 200 parts by weight, more preferably 40 to 150 parts by weight, and even more preferably 50 to 120 parts by weight, based on 100 parts by weight of the carboxyl group-containing vinyl ester resin (A) as a solid component.

[0096] Other ingredients

[0097] The melamine-free photosensitive thermosetting and developable two-component resin composition of the present invention may, of course, contain further additives as other components as needed within the scope of the purpose of the present invention.

[0098] Examples of such other components include colorants such as pigments and dyes, thermal polymerization inhibitors, ultraviolet absorbers, plasticizers, flame retardants, antistatic agents, antioxidants, antibacterial / antifungal agents, defoaming agents, leveling agents, anti-sag agents, thickeners, adhesion-imparting agents, thixotropy-imparting agents, photoinitiator aids, sensitizers, photobase generators, thermoplastic resins, elastomers, organic fillers, release agents, surface treatment agents, dispersants, dispersing aids, surface modifiers, stabilizers, phosphors, and cellulose resins.

[0099] It should be noted that the photosensitive thermosetting and developable two-component resin composition of the present invention does not contain melamine, and therefore the aforementioned other components do not include melamine.

[0100] The compounding ratio of the aforementioned other components is preferably 0.01% by weight or more and 20% by weight or less of the total amount of the photosensitive thermosetting and developable two-component resin composition. If the compounding ratio is less than 0.01% by weight, the corresponding effect cannot be fully obtained, while if the compounding ratio exceeds 20% by weight, the printability and hardness of the photosensitive thermosetting and developable two-component resin composition deteriorate, which is not preferred.

[0101] The first component and the second component of the photosensitive thermosetting and developable two-component resin composition of the present invention can be prepared by mixing and dispersing the respective components to be contained in predetermined amounts, for example, using a three-roll mill.

[0102] dry film

[0103] A dry film can be prepared from the photosensitive and thermosetting developable two-component resin composition of the present invention.

[0104] The dry film of the present invention comprises a resin layer obtained by coating the photosensitive thermosetting developable two-component resin composition of the present invention on a carrier film and drying the resin layer. To form the dry film, the first component and the second component (i.e., the base composition and the curing agent composition) of the photosensitive thermosetting developable two-component resin composition of the present invention are first thoroughly mixed. The mixed composition is then diluted with a solvent to an appropriate viscosity, either as is or as needed. The mixed composition is then applied to a uniform thickness on the carrier film using a comma coater, knife coater, lip coater, rod coater, extrusion coater, reverse coater, transfer roll coater, gravure coater, spray coater, or the like. The applied composition is then dried, typically at a temperature of 50 to 130°C for 1 to 30 minutes, to form the resin layer. The coating film thickness is not particularly limited, but is generally selected within the range of 10 to 150 μm, preferably 20 to 60 μm, based on the dried film thickness.

[0105] As the carrier film, a plastic film is used, for example, polyester film such as polyethylene terephthalate (PET), polyimide film, polyamide-imide film, polypropylene film, polystyrene film, etc. The thickness of the carrier film is not particularly limited, but is generally selected within the range of 10 to 150 μm.

[0106] After forming a resin layer formed from the composition of the present invention on a carrier film, it is preferable to further laminate a removable cover film on the surface of the resin layer to prevent dust from adhering to the surface of the resin layer. Examples of removable cover films include polyethylene films, polytetrafluoroethylene films, polypropylene films, and surface-treated paper. The cover film may be any film as long as it is smaller than the adhesion between the resin layer and the carrier film when the cover film is peeled off.

[0107] It should be noted that in the present invention, the composition of the present invention may be applied to the aforementioned cover film and dried to form a resin layer, and a carrier film may be laminated on the surface of the resin layer. In other words, in the present invention, when producing a dry film, either a carrier film or a cover film may be used as the thin film to which the composition of the present invention is applied.

[0108] Here, a tack-free resin layer can also be formed by adjusting the photosensitive thermosetting, developable two-component resin composition of the present invention to a viscosity suitable for the coating method using, for example, a high-boiling-point solvent, and applying it to a substrate by dip coating, flow coating, roll coating, bar coating, screen printing, curtain coating, or the like, followed by volatilization and drying of the high-boiling-point solvent contained in the composition at a temperature of approximately 60 to 100°C (temporary drying). Alternatively, when the composition is applied to a carrier film or cover film, dried, and wound into a thin film, the resin layer can be formed by laminating the composition layer to the substrate using a laminator or the like so that the layer contacts the substrate, and then peeling off the carrier film.

[0109] As the above-mentioned substrate, in addition to printed circuit boards and flexible printed circuit boards with circuits pre-formed from copper or the like, there can also be mentioned: copper-clad laminates of all grades (FR-4, etc.), as well as metal substrates, polyimide films, PET films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer plates, etc. The copper-clad laminates use materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven fabric epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, and copper-clad laminates for high-frequency circuits using fluorine·polyethylene·polyphenylene ether (polyphenylene oxide)·cyanate ester, etc.

[0110] Cured material

[0111] When forming a cured product using the photosensitive thermosetting developable two-component resin composition of the present invention, the composition is applied to a substrate, the solvent is evaporated and dried, and a resin layer is obtained. The obtained resin layer is exposed (light irradiated) so that the exposed portion (the portion irradiated with light) is cured. Specifically, by contact or non-contact method, active energy rays are selectively exposed through a photomask having a pattern, or a laser direct exposure machine is used to directly expose the pattern, and an alkaline aqueous solution (for example, a 0.3-3% by mass sodium carbonate aqueous solution) is used to develop the unexposed portion to form an etching resist pattern. The product is further heated to a temperature of about 100-180°C and thermally cured (post-cured), thereby forming a cured film (cured product) having excellent properties such as heat resistance, chemical resistance, moisture absorption resistance, adhesion, and electrical properties.

[0112] The volatilization drying or thermal curing when forming the above-mentioned cured product can be carried out, for example, using a hot air circulation drying furnace, IR furnace, hot plate, convection oven, etc. (using a device with a heat source that uses steam to heat the air, a method of making the hot air in the dryer contact by convection, and a method of blowing it onto the support body using a nozzle).

[0113] In addition, as an exposure machine used in the above-mentioned active energy ray irradiation, any device that is equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, etc. and irradiates ultraviolet rays in the range of 350 to 450 nm can be used. Furthermore, a direct drawing device (for example, a laser direct imaging device that directly draws an image with a laser using CAD data from a computer) can also be used. As a lamp light source or a laser light source of a direct drawing machine, the maximum wavelength can be in the range of 350 to 410 nm. The exposure amount used for image formation varies depending on the film thickness, etc., and can usually be set to 20 to 1000 mJ / cm 2 , preferably can be set to 20 to 800 mJ / cm 2 within the range.

[0114] Next, in a development step, the dried coating film after the exposure step is treated with a developer to remove unexposed portions of the coating film, thereby forming a patterned film of the curable composition of the present invention.

[0115] Here, as the method used in the development step, an immersion method, a shower method, a spray method, a brush method, etc. can be used. As the developer, a sodium carbonate aqueous solution with a mass concentration of 0.5 to 5% can generally be used. Other alkaline aqueous solutions can also be used, such as alkaline aqueous solutions of potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, etc.

[0116] In this development step, the temperature of the developer is 20 to 40° C. and the development time is within 180 seconds.

[0117] In the development step, the obtained pattern film may be washed with a rinse solution as needed. As the rinse solution, distilled water, methanol, ethanol, isopropyl alcohol, etc. may be used alone or in combination.

[0118] printed circuit boards

[0119] The present invention can also provide a printed circuit board having the above-mentioned cured product. The photosensitive and thermosetting developable two-component resin composition, dry film or cured product of the present invention can be used as a solder resist for printed circuit boards.

[0120] The present invention will be described in further detail based on Examples and Comparative Examples. However, the scope of the present invention and its embodiments are not limited thereto. "Parts" or "%" in the Examples and Comparative Examples are by weight unless otherwise specified. The properties of the compositions of these Examples were tested using the methods described below.

[0121] Example

[0122] [Synthesis Example: Synthesis of Carboxyl Group-Containing Vinyl Ester Resin]

[0123] In a four-necked flask equipped with a stirrer and a reflux condenser, 214 parts of cresol novolac-type epoxy resin EPICLON N-695 (manufactured by DIC Corporation, epoxy equivalent = 214) were added, followed by 103 parts of carbitol acetate and 103 parts of a petroleum hydrocarbon solvent (manufactured by Japan Energy Corporation, trade name: Cactus Fines SF-01) and dissolved by heating. Subsequently, 0.1 parts of hydroquinone as a polymerization inhibitor and 2.0 parts of triphenylphosphine as a reaction catalyst were added. The mixture was heated to 95-105°C, 72 parts of acrylic acid was slowly added dropwise, and the mixture was allowed to react for 16 hours. The resulting reaction product was cooled to 80-90°C, 91.2 parts of tetrahydrophthalic anhydride was added, the mixture was allowed to react for 8 hours, and then cooled and removed. The resulting carboxyl vinyl ester resin had a nonvolatile content of 65% and an acid value of 87.5 mgKOH / g on the solids.

[0124] The carboxyl group-containing vinyl ester resin solution (varnish) from the synthesis example was blended with the various components and proportions (parts by weight) shown in Table 1. After premixing with a stirrer, the mixture was kneaded with a three-roll mill to prepare a photosensitive thermosetting and developable two-component resin composition. The composition was then evaluated for drying control margin, acid resistance, metal plating resistance, high-temperature storage stability, volatile matter content, and discoloration resistance according to the following methods.

[0125] Table 1 "ND" indicates that the result was not detected and was below the detection limit.

[0126] The components described in Table 1 are as follows.

[0127] *1: Carboxyl vinyl ester resin obtained in Synthesis Example, solid content 65%, solvent 35%

[0128] *2: Pigment: 6Y-501, manufactured by TOYOCOLOR CO., LTD.

[0129] *3: Additives: KS-66, manufactured by Shin-Etsu Chemical Co., Ltd., BYK-1790, manufactured by BYK Additives (Shanghai) Co., Ltd.

[0130] *4: Initiator: ITX, isopropylthioxanthone (manufactured by DKSH JAPAN), #907: α-aminoacetophenone-based photopolymerization initiator (Omnirad 907, manufactured by IGM Resins)

[0131] *5: Filler: B-30, manufactured by Sakai Chemical Industry Co., Ltd., A-8, manufactured by Sibelco

[0132] *6: Solvent: DPM: Dipropylene glycol monomethyl ether, manufactured by Taiwan Leander Co., Ltd.

[0133] *7: Melamine: MELAMINE-JC, manufactured by Jiangsu Jinxiang Sairui Chemical Technology Co., Ltd.

[0134] *8: Melamine phthalate: THPAMELAMINESALT, manufactured by Shikoku Chemical Industry Co., Ltd.

[0135] *9: Epoxy resin: N-770, manufactured by DIC Corporation, novolac-type multifunctional epoxy resin, solid content 100%

[0136] *10: Photosensitive monomer: DPHA, dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd.

[0137] For the photosensitive thermosetting and developable two-component resin compositions of the above Examples and Comparative Examples, the following tests were performed after mixing the first component and the second component.

[0138] <Drying Management Scope (Time from Drying to Exposure and Development)>

[0139] Each composition listed in Table 1 was screen-printed onto the entire surface of a patterned copper foil substrate and dried in a hot air circulation drying oven at 80°C. From 20 to 70 minutes after the start of drying, the substrate was removed every 10 minutes and slowly cooled to room temperature. The substrate was then developed using a 1 wt% sodium carbonate aqueous solution at 30°C at a spray pressure of 0.2 MPa for 60 seconds. The maximum allowable drying time without residue was used as the drying control range.

[0140] ○: The maximum allowable drying time without leaving residue is more than 50 minutes

[0141] ×: The maximum allowable drying time without leaving residue is less than 50 minutes

[0142] <Acid resistance>

[0143] Each composition listed in Table 1 was applied to the entire surface of a substrate having a 2 mm copper wire pattern by screen printing to a thickness of 40 μm, and dried in a hot air circulation drying oven at 80°C for 30 minutes. After cooling to room temperature, the substrate was exposed to light at 400 mJ / cm using an exposure device equipped with a high-pressure mercury lamp. 2 The pattern was exposed, and then developed in a 1 wt% sodium carbonate aqueous solution, a pressure of 0.2 MPa, and a liquid temperature of 30°C for 60 seconds, and then cured in a hot air circulation drying oven at 150°C for 60 minutes. 2 The evaluation substrate was prepared by irradiating ultraviolet light under the conditions of .

[0144] The evaluation substrate was immersed in a 10 vol % H 2 SO 4 aqueous solution at room temperature for 20 minutes, and this was repeated 5 times in total. The impregnation and dissolution of the cured coating film were visually confirmed, and further, the peeling due to tape peeling was confirmed.

[0145] ○: No change observed

[0146] △: Only slight change

[0147] ×: The coating film is bulging or swelling and falling off

[0148] <Metal plating resistance>

[0149] Separate evaluation substrates were prepared using the same method as for the evaluation substrates described in the "Acid Resistance" section above. These evaluation substrates were plated using commercially available electroless nickel and gold plating baths, with nickel at 0.5 μm and gold at 0.03 μm. The presence of plated penetration was evaluated, and the presence of peeling of the cured coating film was evaluated by tape stripping. The evaluation criteria are as follows.

[0150] ○: No penetration or peeling is observed

[0151] △: Slight penetration is observed after plating, and peeling is also observed after stripping.

[0152] ×: Peeling occurs after plating

[0153] <High-temperature storage stability (TS test)>

[0154] Prepare another evaluation substrate using the same method as the evaluation substrate described in <Acid Resistance> above. Place this evaluation substrate in a 160°C oven for several different times and perform a 100-grid test as follows. Record the maximum number of hours in which no peeling occurs during the 100-grid test.

[0155] 100-grid test: After post-baking, use a brand new blade to scratch the surface of the cured coating at a 30° angle to the board surface, creating a grid pattern. Then, use 3M tape to perform a peel test. The judgment criteria are as follows.

[0156] ○: The high temperature storage time without falling off in the 100-grid test is more than 1000 hours

[0157] ×: The high temperature storage time without falling off in the 100-grid test is less than 1000 hours

[0158] <Volatile Matter Evaluation>

[0159] Another evaluation substrate was prepared using the same method as the evaluation substrate described in <Acid Resistance>. The cured coating film was pretreated after post-curing according to US EPA 3550C:2007 and analyzed for volatile matter content using HPLC, GC-MC, and LC-MS-MS.

[0160] The smaller the amount of volatile matter measured by LC-MS / MS, the less harmful substances are volatilized during the welding process. In the present invention, a volatile matter content of less than 1000 ppm is considered acceptable.

[0161] <Discoloration resistance>

[0162] A separate evaluation substrate was prepared by the same method as the evaluation substrate described in <Acid Resistance>. The L values ​​of the cured coating film were measured using a spectrophotometer CM-2600d manufactured by Konica Minolta. * a * b * Then, heat treatment was performed at 150°C for 2 hours (i.e., accelerated degradation), and L was measured in the same way. * a * b * . ΔEab was calculated from the measured value using the following formula. ΔEab=((L * 2-L * 1) 2 +(a * 2-a * 1) 2 +(b * 2-b * 1) 2 ) 0.5

[0163] (Where, L* 1.a * 1.b * 1 represents L before heating treatment * 、a * 、b * The value of L * 2.a * 2. b * 2 respectively represent L after heating treatment * 、a * 、b * .)

[0164] Here, ΔEab is calculated as L * a * b * The difference between the initial value and the value after accelerated degradation in the colorimetric system. The larger the value, the more likely it is to undergo oxidative discoloration, indicating a low discoloration resistance.

[0165] As shown above, Examples 1-4, by incorporating melamine phthalate in appropriate amounts, can produce melamine-free, photosensitive, thermosetting, developable, two-component resin compositions that are excellent in all evaluations of drying control margin, acid resistance, metal plating resistance, high-temperature storage stability, volatiles, and discoloration resistance. In contrast, Comparative Example 1, which contains neither melamine nor phthalate, exhibits poor acid resistance, metal plating resistance, and discoloration resistance in the resulting cured product. Comparative Example 2, which contains a small amount of melamine, and Comparative Example 7, which contains an insufficient amount of melamine phthalate, exhibit slightly improved acid resistance and metal plating resistance compared to Comparative Example 1, but these are still insufficient, and discoloration resistance remains poor. Comparative Examples 2-6, while using a certain amount of melamine improves acid resistance, metal plating resistance, and discoloration resistance, significantly increases volatiles. In Comparative Example 6 containing a large amount of melamine and Comparative Example 8 containing an excessive amount of melamine phthalate, the drying control range was poor and the amount of volatile matter was slightly high.

[0166] These results demonstrate that the melamine-free, photosensitive and thermosetting, two-component resin composition of the present invention has an excellent drying control margin, can reduce the volatilization of harmful substances during the soldering stage, and can produce a cured product with excellent acid resistance, metal plating resistance, high-temperature storage properties, and discoloration resistance. The melamine-free, photosensitive and thermosetting, two-component resin composition of the present invention, dry films obtained therefrom, and cured products thereof are suitable for use as solder resists for printed circuit boards.

Claims

1. A melamine-free photosensitive thermosetting developable two-component resin composition, characterized in that: The invention comprises (A) a carboxyl-containing vinyl ester resin, (B) a photopolymerization initiator, (C) a melamine phthalate and (D) an epoxy resin, wherein the (A) carboxyl-containing vinyl ester resin and the (B) photopolymerization initiator are contained in a first component, the (D) epoxy resin is contained in a second component different from the first component, and the (C) melamine phthalate is contained in an amount of 1.2 to 11.8 parts by weight relative to 100 parts by weight of the (A) carboxyl-containing vinyl ester resin in terms of solid content.

2. The melamine-free photosensitive thermosetting developable two-component resin composition according to claim 1, characterized in that: The amount of the melamine phthalate (C) is 1.8 to 18.2 parts by weight relative to 100 parts by weight of the epoxy resin (D) in terms of solid content.

3. The melamine-free photosensitive thermosetting developable two-component resin composition according to claim 1 or 2, characterized in that: The (C) melamine phthalate is contained in the first component.

4. The melamine-free photosensitive thermosetting developable two-component resin composition according to claim 1 or 2, characterized in that: It also contains (E) an inorganic filler.

5. The melamine-free photosensitive thermosetting developable two-component resin composition according to claim 4, characterized in that: The (E) inorganic filler is contained in the first component.

6. The melamine-free photosensitive thermosetting developable two-component resin composition according to claim 1 or 2, characterized in that: (F) A photosensitive monomer is also contained.

7. The melamine-free photosensitive thermosetting developable two-component resin composition according to claim 6, characterized in that: The (F) photosensitive monomer is contained in the second component.

8. The melamine-free photosensitive thermosetting developable two-component resin composition according to claim 1 or 2, characterized in that: The first component and / or the second component further contains (G) an organic solvent.

9. The melamine-free photosensitive thermosetting developable two-component resin composition according to claim 1 or 2, characterized in that: For solder resist.

10. A dry film, characterized in that: The invention comprises: a carrier film; and a resin layer obtained by applying the melamine-free photosensitive thermosetting developable two-component resin composition according to any one of claims 1 to 9 on the carrier film and drying the coating.

11. A solidified product, characterized in that: The photosensitive thermosetting developable two-component resin composition free of melamine according to any one of claims 1 to 9 is cured.

12. A solidified product, characterized in that: This is obtained by curing the resin layer of the dry film according to claim 10.

13. A printed circuit board, characterized in that: A cured product according to claim 11 or 12.

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