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

Abstract

The present invention provides a melamine-free photosensitive thermosetting developable two-component resin composition, a dry film thereof, a cured product thereof, and a printed circuit board using the same, wherein the cured product has excellent acid resistance, metal plating resistance, high temperature storage capacity, and discoloration resistance, and the volatilization of harmful substances during the soldering process is reduced, and the drying control range is excellent. The melamine-free photosensitive thermosetting developable two-component resin composition contains (A) a carboxyl group-containing vinyl ester resin, (B) a photopolymerization initiator, (C) a melamine phthalate, and (D) an epoxy resin, wherein (A) the carboxyl group-containing vinyl ester resin and (B) the photopolymerization initiator are contained in a first agent, (D) the epoxy resin is contained in a second agent different from the first agent, and (C) the melamine phthalate is in an amount of 1.2 to 11.8 parts by weight per 100 parts by weight of (A) the carboxyl group-containing vinyl ester resin on a solid content basis.

Description

[Technical Field]

[0001] The present invention relates to a melamine-free photosensitive thermosetting developable two-component resin composition, a dry film thereof, and a cured product thereof. In particular, the present invention relates to a melamine-free photosensitive thermosetting developable two-component resin composition, a dry film thereof, and a cured product thereof, which are suitably used for forming solder resists in long-reliability printed circuit boards. [Background technology]

[0002] Until now, solder resist (also called solder resist ink) has been used on printed circuit boards (PCBs) as a protective material for the circuits on the circuit board. Currently, some consumer-grade PCBs and most industrial PCBs use alkali-developable solder resist, which is developed by ultraviolet exposure to form a pattern and then fully cured (completely hardened) by heat and / or light irradiation. Furthermore, in semiconductor equipment used in vehicles such as automobiles, trains, ships, and aircraft, there is a growing trend to use solder resist designed for high-reliability electronic materials as the solder resist for long-term reliability PCBs.

[0003] Commercially available solder resist inks typically contain melamine, which acts as both a thermosetting agent and an antioxidant, improving the ink's properties such as acid resistance, alkali resistance, metal plating resistance, and adhesion. However, melamine in the ink has several problems, including the fact that it volatilizes during the soldering process (usually at 260°C) and that, according to the European Union's REACH Regulation (Registration, Evaluation, Authorisation and Restriction of Chemicals), it is an environmentally regulated substance that falls under the category of SVHC (Substances of Very High Concern).

[0004] For example, melamine is used in all of the following: the highly adhesive solder resist coating layer disclosed in Patent Document 1, the two-component solder mask photoresist disclosed in Patent Document 2, and the highly resolving solder resist ink disclosed in Patent Document 3. Patent Document 4 discloses a photosensitive solder resist ink in which the coating film has better durability and corrosion resistance by adding a melamine copolymer resin to the curing agent. Patent Document 5 discloses a thermosetting ink that has resistance to yellowing and does not dry out the screen mesh by grafting a modified melamine, such as dimethoxymelamine, trimethoxymelamine, tetramethylolmelamine, methylenemelamine, or methyl etherified melamine, onto an epoxy resin. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] CN116239938A [Patent Document 2] CN116560187A [Patent Document 3] CN111100499A [Patent Document 4] CN114605867A [Patent Document 5] CN114656833A [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Conventionally, solder resist inks usually contain melamine as a heat curing agent and an antioxidant. Since environmental requirements are becoming increasingly strict, reduction or avoidance of the use of melamine is desired. However, as a result of investigations by the present inventors, it has been found that when the amount of melamine used in conventional solder resist inks (for example, Patent Documents 1 to 3) is reduced, properties such as acid resistance and metal plating resistance after post-baking (i.e., post-curing) of the solder resist ink deteriorate. In addition, in the prior art, attempts have been made to use a resin derived from melamine as a curing agent or a curing component, but it has not been possible to simultaneously satisfy the requirements for the drying management range and acid resistance, metal plating resistance, high-temperature storage stability, and discoloration resistance. For example, since the molecular weight of the melamine copolymer resin used in Patent Document 4 is large, sufficient thermosetting properties and antioxidant properties cannot be imparted to the solder resist ink. Trimethoxymelamine used in Patent Document 5 has a methoxy group, and thus has high reactivity in thermosetting inks, but when used in developing inks, the developability is low and it is not practical.

[0007] Therefore, there is an urgent need to produce a developing resin composition that is excellent in the drying management range without using melamine, and further has excellent acid resistance, metal plating resistance (electroless plating resistance), high-temperature storage stability, and discoloration resistance (i.e., is difficult to oxidize and discolor) of the cured product.

[0008] Therefore, an object of the present invention is to provide a melamine-free photosensitive thermosetting developing two-component resin composition in which the cured product has excellent acid resistance, metal plating resistance, high-temperature storage stability, and discoloration resistance, and in which the volatilization of harmful substances is reduced in the soldering process and the drying management range is excellent.

[0009] Furthermore, an object of the present invention is to provide a dry film and a cured product having excellent properties as described above, obtained by using such a melamine-free photosensitive thermosetting developing two-component resin composition, and a printed wiring board formed by forming a cured film such as a solder resist using such a melamine-free photosensitive thermosetting developing two-component resin composition, its dry film or its cured product.

Means for Solving the Problem

[0010] As a result of intensive studies to solve the above problems, the present inventors have found that in a photosensitive thermosetting developable two-component resin composition, when a specific amount of melamine phthalate is used instead of melamine as a curing agent and an antioxidant, the melamine phthalate does not volatilize during soldering due to its unique structure, and furthermore, its antioxidant performance is the same as that of melamine. When the melamine-free photosensitive thermosetting developable two-component resin composition thus obtained is used as solder resist ink, it has been found that other properties are substantially the same.

[0011] In addition, the present inventors have found that the above problems can be solved by the following melamine-free photosensitive thermosetting developable two-component resin composition, and have completed the present invention. The melamine-free photosensitive thermosetting developable two-component resin composition contains (A) a carboxyl group-containing vinyl ester resin, (B) a photopolymerization initiator, (C) melamine phthalate, and (D) an epoxy resin. The (A) carboxyl group-containing vinyl ester resin and the (B) photopolymerization initiator are contained in the first agent, the (D) epoxy resin is contained in a second agent different from the first agent, and the (C) melamine phthalate is 1.2 to 11.8 parts by weight with respect to 100 parts by weight of the (A) carboxyl group-containing vinyl ester resin in terms of solid content.

[0012] In a preferred embodiment of the present invention, in the melamine-free photosensitive thermosetting developable two-component resin composition, the (C) melamine phthalate is 1.8 to 18.2 parts by weight with respect to 100 parts by weight of the (D) epoxy resin in terms of solid content.

[0013] In a preferred embodiment of the present invention, the (C) melamine phthalate is contained in the first agent.

[0014] In a preferred embodiment of the present invention, the melamine-free photosensitive thermosetting developable two-component resin composition further contains (E) an inorganic filler.

[0015] In a more preferred embodiment of the present invention, in the melamine-free photosensitive thermosetting developable two-component resin composition, the (E) inorganic filler is included in the first agent.

[0016] In a preferred embodiment of the present invention, the melamine-free photosensitive thermosetting developable two-component resin composition further contains (F) a photosensitive monomer.

[0017] In a more preferred embodiment of the present invention, in the melamine-free photosensitive thermosetting developable two-component resin composition, the (F) photosensitive monomer is included in the second agent.

[0018] In a preferred embodiment of the present invention, in the melamine-free photosensitive thermosetting developable two-component resin composition, the first agent and / or the second agent further contain (G) an organic solvent.

[0019] Furthermore, another embodiment of the present invention relates to a dry film characterized by comprising a carrier film and a resin layer obtained by applying and drying the melamine-free photosensitive thermosetting developable two-component resin composition onto the carrier film.

[0020] Another embodiment of the present invention relates to the melamine-free photosensitive thermosetting developable two-component resin composition, characterized in that it is used in a solder resist.

[0021] Another embodiment of the present invention relates to a cured product characterized by being obtained by curing the melamine-free photosensitive thermosetting developable two-component resin composition.

[0022] Another embodiment of the present invention relates to a cured product characterized by being obtained by curing the resin layer of the dry film.

[0023] Another embodiment of the present invention relates to a printed circuit board characterized by having the cured product. [Effects of the Invention]

[0024] As described above, the present invention provides a melamine-free photosensitive thermosetting two-component resin composition, its dry film, its cured product, and printed circuit board, in which the cured product has excellent acid resistance, metal plating resistance, high-temperature storage properties, and discoloration resistance, and in which the volatilization of harmful substances during the soldering process is reduced and the drying control range is excellent. [Modes for carrying out the invention]

[0025] The melamine-free, photosensitive, thermosetting, and developable two-component resin composition of the present invention will be described below.

[0026] The melamine-free photosensitive thermosetting developable two-component resin composition of the present invention (hereinafter sometimes simply referred to as "photosensitive thermosetting developable two-component resin composition," "two-component resin composition," or "composition") contains (A) a carboxyl group-containing vinyl ester resin, (B) a photopolymerization initiator, (C) a melamine phthalate, and (D) an epoxy resin, wherein (A) the carboxyl group-containing vinyl ester resin and (B) the photopolymerization initiator are contained in a first agent, (D) the epoxy resin is contained in a second agent different from the first agent, and (C) the melamine phthalate is in an amount of 1.2 to 11.8 parts by weight per 100 parts by weight of the carboxyl group-containing vinyl ester resin (A) on a solid content basis.

[0027] The melamine-free photosensitive thermosetting developable two-component resin composition of the present invention comprises a first agent and a second agent different from the first agent. Herein, "two-component" means that it consists of at least two components. Therefore, the two-component resin composition of the present invention may further contain other components, such as a third agent, in addition to the first and second agents.

[0028] An example of a two-component system is a system in which one resin composition is the main component and the other resin composition is the curing agent. In the case of a two-component resin composition, the different components, such as the main component and the curing agent, are mixed immediately before use. However, to prevent the components from mixing and reacting during the manufacturing, storage, and transportation processes, the different components exist independently of each other and do not come into contact with each other.

[0029] In the present invention, the first component containing (A) a carboxyl group-containing vinyl ester resin and (B) a photopolymerization initiator can be used as the main component composition, and the second component containing (D) an epoxy resin can be used as the curing agent composition. Therefore, in the two-component resin composition of the present invention, from the viewpoint of avoiding the main component and curing agent reacting during storage and impairing the performance as a solder resist ink, it is preferable that the first component does not contain (D) epoxy resin, and the second component does not contain (A) a carboxyl group-containing vinyl ester resin and (B) a photopolymerization initiator.

[0030] The following describes each component contained in the melamine-free photosensitive thermosetting developable two-component resin composition of the present invention.

[0031] (A) Carboxyl group-containing vinyl ester resin The first component of the two-component resin composition of the present invention comprises (A) a carboxyl group-containing vinyl ester resin. As the (A) carboxyl group-containing vinyl ester resin used in the present invention, a carboxyl group-containing vinyl ester resin having an ethylenically unsaturated double bond in the molecule is particularly preferred from the viewpoint of providing alkali developability, photocurability, and developability. Examples include 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. Specific examples of carboxyl group-containing vinyl ester resins are shown below. (1) A carboxyl group-containing vinyl ester resin obtained by reacting 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 an alcoholic hydroxyl group that reacts with an epoxy group in one molecule, with a saturated or unsaturated polybasic acid anhydride. (2) A carboxyl group-containing vinyl ester resin obtained by reacting a polyfunctional epoxy resin with an unsaturated monocarboxylic acid, followed by a polybasic acid anhydride, with a compound having one oxirane ring and one or more ethylenically unsaturated groups in its molecule. (3) A carboxyl group-containing vinyl ester resin obtained by reacting a polyfunctional epoxy resin such as a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, a bisphenol A cresol novolac type epoxy resin, or a dicyclopentadiene cresol novolac type 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 chain. (4) A carboxyl group-containing vinyl ester resin obtained by reacting a polyfunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of the polyfunctional epoxy resin of (3) with epichlorohydrin with (meth)acrylic acid, and adding a polybasic acid anhydride to the resulting hydroxyl groups. (5) A carboxyl group-containing vinyl ester resin obtained by adding a cyclic ether such as ethylene oxide or a cyclic carbonate such as propylene carbonate to a polyfunctional phenol compound such as novolac resin, partially esterifying the resulting hydroxyl group with (meth)acrylic acid, and reacting the remaining hydroxyl group with a polybasic acid anhydride. (6) A carboxyl group-containing vinyl ester resin obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in its molecule, such as glycidyl (meth)acrylate or α-methylglycidyl (meth)acrylate, to any of the resins in (3) to (5) above.

[0032] Particularly preferred among these examples are cresol novolac type and phenol novolac type carboxyl group-containing vinyl ester resins, i.e., the carboxyl group-containing vinyl ester resins of (3), (4), (5), and (6) above.

[0033] In this specification, (meth)acrylate is a general term referring to acrylates, methacrylates, and mixtures thereof, and the same applies to other similar expressions.

[0034] As described above, (A) carboxyl group-containing vinyl ester resins have numerous free carboxyl groups in the side chains of the main chain polymer, and therefore can be developed with dilute alkaline aqueous solutions.

[0035] Furthermore, the acid value of the carboxyl group-containing 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 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 is promoted, so the lines become finer than necessary, and the exposed and unexposed areas are dissolved and peeled off by the developer without distinction, making it difficult to draw a normal resist pattern, which is undesirable.

[0036] Furthermore, the weight-average molecular weight of the carboxyl group-containing vinyl ester resin (A) varies depending on the resin skeleton, but is generally preferably between 2,000 and 150,000, and more preferably between 5,000 and 100,000. If the weight-average molecular weight is less than 2,000, the tack-free properties (touch-dry properties) after coating and drying on the substrate may be poor, and furthermore, the moisture resistance of the coating film after exposure may deteriorate, the amount of film obtained during development may decrease, and the resolution may be significantly reduced. On the other hand, if the weight-average molecular weight exceeds 150,000, the developability may deteriorate significantly, and storage stability may worsen.

[0037] (A) The amount of carboxyl group-containing vinyl ester resin blended is preferably in the range of 20 to 60% by mass of the total composition in terms of solid content, and preferably 25 to 50% by mass. (A) If the amount of carboxyl group-containing vinyl ester resin blended is less than the above range, the coating strength will decrease, which is undesirable. On the other hand, if the amount blended exceeds the above range, the tackiness of the composition will increase or the applicability will decrease, which is undesirable.

[0038] (B) Photopolymerization initiator The first component of the photosensitive thermosetting developable two-component resin composition of the present invention comprises (B) a photopolymerization initiator. The (B) photopolymerization initiator can be any photopolymerization initiator commonly used in photosensitive thermosetting developable resin compositions, without any particular limitations.

[0039] (B) Known photopolymerization initiators can be used. For example, 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- Bisacylphosphine oxides such as (2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine methyl, 2-methylbenzoyldiphenylphosphine oxide, isopropyl pivaloylphenylphosphine, 2,4,6- Monoacylphosphine oxides such as methylbenzoyldiphenylphosphine oxide and 2,4,6-trimethylbenzoyl-di-p-toluylphosphine oxide; 1-hydroxycyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-hydroxy-2-methyl-1-phenyl Hydroxyacetophenones such as phenylpropan-1-one; benzoins such as benzoin, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and benzoin n-butyl ether; benzoin alkyl ethers; benzophenones such as benzophenone, p-methylbenzophenone, Michlar's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bisdiethylaminobenzophenone;Acetophenones such as 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)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, N,N-dimethylaminoacetophenone, etc.; thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropyl Thioxanthones such as thioxanthone; anthraquinones such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzoic acid esters such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, and p-dimethylbenzoate ethyl ester; oxime esters such as 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyl oxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyl oxime); bis(η; 5 Examples include titanosenes such as -2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl)titanium and bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyrrole-1-yl)ethyl)phenyl]titanium; phenyldithio-2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, tetramethylthiuram disulfide, etc. (B) The photopolymerization initiator may be used alone or in combination of two or more.

[0040] (B) Commercially available photopolymerization initiators include oxime esters such as Irgacure OXE01 and Irgacure OXE02 from BASF Japan, and N-1919 and NCI-831 from ADEKA CORPORATION; α-hydroxyalkylphenones such as Omnirad 184, Omnirad 1173, Omnirad 2959 and Omnirad 127 from IGM Resins BV; acetophenones such as Omnirad 907, Omnirad 369 and Omnirad 379 from IGM Resins BV; acylphosphine oxides such as Omnirad TPO from IGM Resins, Ltcure TMO from PhiChem, and Omnirad 819 and Omnipol TP from IGM Resins BV; and titanocenes such as Omnirad 784 from IGM Resins BV.

[0041] The blending ratio of these (B) photopolymerization initiators is preferably 0.01 to 30 parts by weight, more preferably 5 to 25 parts by weight, and more preferably 10 to 20 parts by weight, per 100 parts by weight of the (A) carboxyl group-containing vinyl ester resin on a solid content basis. If the amount of (B) 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 of the two-component resin composition of the present invention as a solder resist will be reduced, which is undesirable.

[0042] (C) Melamine phthalate The photosensitive thermosetting developable two-component resin composition of the present invention contains (C) melamine phthalate. This (C) melamine phthalate may be contained in either the first or second component, but it is preferably contained in the first component, i.e., it is preferably contained in the main component composition.

[0043] The inventors compared the weight loss (i.e., weight of volatile matter) after heat curing of photosensitive thermosetting developable two-component resin compositions with melamine and melamine phthalate added, respectively. They found that the composition with melamine phthalate added had significantly less volatile matter than the composition with melamine added, and that the composition with melamine phthalate added could achieve almost the same level of drying control range, high-temperature storage capacity, discoloration resistance, acid resistance, and metal plating resistance of the cured product as the composition with melamine added. Although the principle is not yet fully understood, the inventors speculate as follows: Melamine phthalate contains the structure of melamine in its structure, and therefore functions as a curing agent and antioxidant, similar to melamine. In other words, melamine phthalate can improve the adhesion between the substrate with the copper circuit and the cured product by preventing oxidation of the copper circuit. As a result, acid resistance, metal plating resistance, and high-temperature storage capacity are improved. Furthermore, melamine phthalate suppresses discoloration of the copper circuit, which is the base of the cured product, thereby improving the discoloration resistance of the cured product. On the other hand, due to its unique structure, melamine phthalate remains relatively stable in the composition during the soldering process, which is usually carried out at 260°C, and does not volatilize in large quantities like melamine. Therefore, when melamine phthalate is used instead of melamine, the volatilization of harmful substances during soldering can be reduced without affecting the various properties of the composition.

[0044] (C) The blending ratio of melamine phthalate 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) on a solid content basis. If the amount of (C) melamine phthalate used is less than 1.2 parts by weight, it cannot function effectively as a curing agent and antioxidant, resulting in a cured product with poor discoloration resistance, and tends to have insufficient acid resistance, high-temperature storage resistance, and metal plating resistance. If the amount of (C) melamine phthalate used exceeds 11.8 parts by weight, the drying range of the composition becomes poor, and volatile matter increases significantly during soldering.

[0045] (D) Epoxy resin The second component in the photosensitive thermosetting developable two-component resin composition of the present invention contains (D) epoxy resin. This (D) epoxy resin functions as a thermosetting component in the photosensitive thermosetting developable two-component resin composition of the present invention and forms a cured product.

[0046] As such epoxy resins, known and conventional polyfunctional epoxy resins having at least two epoxy groups in one molecule can be used.

[0047] The epoxy resin (D) used in the present invention may be liquid at room temperature, solid, or semi-solid.

[0048] Preferred polyfunctional epoxy resins include, but are not limited to, bisphenol A type epoxy resins, brominated epoxy resins, novolac type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, glycidylamine type epoxy resins, hydantoin type epoxy resins, alicyclic epoxy resins, trihydroxyphenylmethane type epoxy resins, bixylenol type or biphenol type epoxy resins or mixtures thereof, bisphenol S type epoxy resins, bisphenol A novolac type epoxy resins, tetraphenyloleethane type epoxy resins, heterocyclic epoxy resins, diglycidyl phthalate resins, tetraglycidyl xylenoylethane resins, naphthalene group-containing epoxy resins, epoxy resins having a dicyclopentadiene skeleton, glycidyl methacrylate copolymer epoxy resins, copolymer epoxy resins of cyclohexylmaleimide and glycidyl methacrylate, epoxy-modified polybutadiene rubber derivatives, CTBN-modified epoxy resins, and epoxy resins having an isocyanuric ring. These epoxy resins can be used individually or in combination of two or more types.

[0049] "Epoxy resins that are solid or semi-solid at room temperature" can also be those that are known and commonly used. For example, epoxy resins that are solid at room temperature include bisphenol A type epoxy resin (JER1001, manufactured by Mitsubishi Chemical Corporation), bisphenol F type epoxy resin (JER4004P, manufactured by Mitsubishi Chemical Corporation), naphthalene type epoxy resin (HP-4700, manufactured by DIC Corporation), naphthalene skeleton-containing polyfunctional solid epoxy resin (NC-7000, manufactured by Nippon Kayaku Co., Ltd.), trisphenol epoxy resin (EPPN-502H, manufactured by Nippon Kayaku Co., Ltd.), dicyclopentadiene skeleton-containing polyfunctional solid epoxy resin (Epiclon HP-7200, HP-7200H, manufactured by DIC Corporation), phosphorus-containing epoxy resin (TX0712, manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), and tris(2,3-epoxypropyl) isocyanurate (TEPIC, manufactured by Nissan Chemical Industries, Ltd.). As for epoxy resins that are semi-solid at room temperature, there is bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation). Examples include jER834), naphthalene-type epoxy resins (HP-4032, EXA-4750, EXA-4700 manufactured by DIC Corporation, and ESN-190, ESN-360 manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0050] Here, in this invention, "solid or semi-solid at room temperature" means that the substance is solid or semi-solid at 15°C. The determination of whether a substance is solid or semi-solid can be made in accordance with the "Method for confirming liquid status" in Appendix 2 of the Ministerial Ordinance Concerning the Testing and Properties of Hazardous Materials (Ministry of Home Affairs Ordinance No. 1 of 1989).

[0051] As biphenyl-type epoxy resins, known and conventional polyfunctional epoxy resins having a biphenyl skeleton can be used. Examples include biphenyl skeleton-containing polyfunctional solid epoxy resins (NC-3000H, NC-3000, manufactured by Nippon Kayaku Co., Ltd.) and biphenyl-type epoxy resins (YX-4000, YL-6121HA, manufactured by Mitsubishi Chemical Corporation).

[0052] Examples of novolac-type epoxy resins include cresol novolac-type epoxy resin (Epiclon N-690, manufactured by DIC Corporation) and phenol novolac-type epoxy resins (Epiclon N-770, manufactured by DIC Corporation, and jER152, manufactured by Mitsubishi Chemical Corporation).

[0053] The epoxy resin content described above is preferably in the range of approximately 30 to 100 parts by weight, more preferably in the range of 40 to 90 parts by weight, and even more preferably in the range of 50 to 85 parts by weight, based on the solid content of 100 parts by weight of the (A) carboxyl group-containing vinyl ester resin.

[0054] From the viewpoint of further demonstrating the effects of the present invention, such as improved discoloration resistance and reduced volatilization of harmful substances during the soldering process, the amount of (C) melamine phthalate 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 per 100 parts by weight of (D) epoxy resin on a solid content basis.

[0055] (E) Inorganic filler The melamine-free photosensitive thermosetting developable two-component resin composition of the present invention may contain (E) an inorganic filler. (E) The inorganic filler may be used alone or in combination of two or more types.

[0056] (E) Examples of inorganic fillers include titanium dioxide, silica, barium sulfate, barium titanate, Neuburg silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, and aluminum nitride. Among these, it is preferable to include at least one of talc, silica, and barium sulfate, as this can suppress curing shrinkage of the cured product of the photosensitive thermosetting developable two-component resin composition and improve properties such as adhesion, hardness, and gloss.

[0057] From the viewpoint of improving the mechanical properties, high-temperature storage resistance, processability, and chemical resistance of the cured product, it is preferable that (E) an inorganic filler is included in the main component, that is, it is preferable that it is included in the first component of the two-component resin composition of the present invention. In this case, at least one of silica and barium sulfate is preferred as the (E) inorganic filler.

[0058] (E) Inorganic fillers can be surface-treated, and it is more preferable that their surfaces are surface-treated to allow for the introduction of curable reactive groups.

[0059] Here, a curable reactive group refers to a group that undergoes a curing reaction with (A) a carboxyl group-containing vinyl ester resin, (E) an epoxy resin, etc., and may be either a photocurable reactive group or a thermosetting reactive group. Examples of photocurable reactive groups include methacrylic group, acrylic group, vinyl group, styryl group, etc., while examples of thermosetting reactive groups include epoxy group, amino group, hydroxyl group, carboxyl group, isocyanate group, imino group, oxetanyl group, mercapto group, methoxymethyl group, methoxyethyl group, ethoxymethyl group, ethoxyethyl group, oxazoline group, etc.

[0060] The method for introducing curable reactive groups to the surface of an inorganic filler is not particularly limited and can be done using known and conventional methods. The surface of the inorganic filler can be treated with a surface treatment agent having curable reactive groups, such as a coupling agent having curable reactive groups as organic groups. Examples of coupling agents that can be used include silane coupling agents, titanium coupling agents, zirconium coupling agents, and aluminum coupling agents. Examples of inorganic fillers treated with surface treatment agents that do not have curable reactive groups include those treated with silica-alumina surface treatment, titanate-based coupling agent treatment, aluminate-based coupling agent treatment, and organic treatment.

[0061] (E) Examples of inorganic filler shapes include spherical, needle-shaped, plate-shaped, flaky, hollow, irregularly shaped, hexagonal, cubic, and flake-shaped, and a spherical shape is preferred from the viewpoint of high filling performance of the inorganic filler.

[0062] (E) The average particle size (D50) of the inorganic filler is 2000 nm or less, and more preferably 1200 nm or less. The lower limit is preferably 0.1 nm or more for the average particle size (D50).

[0063] (E) The smaller the average particle size of the inorganic filler, the more diffuse reflection is suppressed during light irradiation, making it easier to perform fine processing of the cured material pattern. The average particle size (D50) can be determined using a laser diffraction particle size distribution analyzer or a dynamic light scattering analyzer. Examples of laser diffraction analyzers include the MicrotracMT3300EXII from Microtrac-Bell, and examples of dynamic light scattering analyzers include the Nanotrac Wave II UT151 from Microtrac-Bell.

[0064] (E) The amount of inorganic filler added is preferably in the range of 20 to 240 parts by weight, more preferably in the range of 50 to 200 parts by weight, and even more preferably in the range of 80 to 160 parts by weight, based on the solid content of 100 parts by weight of the (A) carboxyl group-containing vinyl ester resin. When the amount of inorganic filler added is 20 parts by weight or more, a cured film with excellent acid resistance, metal plating resistance, and discoloration resistance tends to be obtained. When the amount of inorganic filler added is 240 parts by weight or less, a photosensitive thermosetting developable two-component resin composition with excellent defoaming properties, resolution, and deep curing properties tends to be obtained.

[0065] (F) Photosensitive monomer The melamine-free photosensitive thermosetting developable two-component resin composition of the present invention may contain (F) a photosensitive monomer. (F) may be used alone or in combination of two or more types.

[0066] The (F) photosensitive monomer in the present invention is not particularly limited, and known and conventional photosensitive monomers can be used. The (F) photosensitive monomer may be, for example, a compound having one or more ethylenically unsaturated groups in its molecule. Such a photosensitive monomer (if it contains ethylenically unsaturated groups) assists in the photocuring of the (A) carboxyl group-containing vinyl ester resin by active energy ray irradiation, thereby curing the photosensitive thermosetting developable two-component resin composition.

[0067] (F) The photosensitive monomer is preferably included in the curing agent, that is, preferably in the second component of the two-component resin composition of the present invention, from the viewpoint of avoiding reaction during storage that impairs the performance as a solder resist.

[0068] The photosensitive monomer (F) preferably used in the present invention is, for example, methyl α-(allyloxymethyl)acrylate, or 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,Diacrylates of diols such as 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, diacrylate of diols obtained by adding at least one of ethylene oxide and propylene oxide to neopentyl glycol, diacrylates of glycols such as caprolactone-modified hydroxypivalic acid neopentyl glycol diacrylate, EO adduct diacrylate of bisphenol A, PO adduct diacrylate of bisphenol A, tricyclodecanedimethanol diacrylate, hydrogenated dicyclopentadienyl diacrylate, cyclohexyl diacrylate, and other cyclic diacrylates, or corresponding methacrylate monomers. Examples include polyfunctional acrylates such as methacrylate, 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 phosphate triacrylate, epichlorohydrin-modified glycerol triacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, or silsesquioxane-modified products thereof, or corresponding methacrylate monomers, trifunctional methacrylates, polyfunctional (meth)acrylates such as ε-caprolactone-modified tris(acryloyloxyethyl) isocyanurate, or combinations of two or more of these.

[0069] The content of such (F) photosensitive monomer is preferably in the range of 5 to 90 parts by weight, more preferably in the range of 20 to 60 parts by weight, and even more preferably in the range of 30 to 50 parts by weight, based on the solid content of 100 parts by weight of the (A) carboxyl group-containing vinyl ester resin.

[0070] (F) If the content of the photosensitive monomer is within this range, the melamine-free photosensitive thermosetting developable two-component resin composition will have sufficient photocurability, resulting in better patterning during development and good touch-drying properties.

[0071] (G) Organic solvents In the melamine-free photosensitive thermosetting developable two-component resin composition of the present invention, at least one component can be (G) an organic solvent in order to synthesize the (A) carboxyl group-containing vinyl ester resin and prepare each component in the composition, or to adjust the overall viscosity of the composition obtained by mixing the components in order to coat it on a substrate or a carrier film.

[0072] 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 solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. The organic solvents can be used individually or as a mixture of two or more.

[0073] The content of such (G) organic solvent is preferably in the range of 30 to 200 parts by weight, more preferably in the range of 40 to 150 parts by weight, and even more preferably in the range of 50 to 120 parts by weight, based on the solid content of 100 parts by weight of the (A) carboxyl group-containing vinyl ester resin.

[0074] Other ingredients In the melamine-free photosensitive thermosetting developable two-component resin composition of the present invention, it is of course possible to incorporate further additives as other components as necessary, without departing from the objectives of the present invention.

[0075] Other such components include, for example, colorants such as pigments and dyes, thermal polymerization inhibitors, ultraviolet absorbers, plasticizers, flame retardants, antistatic agents, anti-aging agents, antibacterial and antifungal agents, defoaming agents, leveling agents, anti-sagging agents, thickeners, adhesion promoters, thixotropic agents, photoinitiator aids, sensitizers, photobase generators, thermoplastic resins, elastomers, organic fillers, mold release agents, surface treatment agents, dispersants, dispersion aids, surface modifiers, stabilizers, phosphors, cellulose resins, and the like.

[0076] Furthermore, since the photosensitive thermosetting developable two-component resin composition of the present invention does not contain melamine, the other components mentioned above do not contain melamine.

[0077] The blending 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 developable two-component resin composition. If it is less than 0.01% by weight, the above effect cannot be sufficiently obtained, and if it exceeds 20% by weight, the printability and hardness of the photosensitive thermosetting developable two-component resin composition will deteriorate, which is undesirable.

[0078] The first and second components of the photosensitive thermosetting developable two-component resin composition of the present invention can each be prepared by mixing and dispersing their respective components in predetermined amounts, for example, using a three-roll mill.

[0079] Dry film A dry film can be produced from the photosensitive thermosetting developable two-component resin composition of the present invention.

[0080] The dry film of the present invention has a resin layer obtained by coating and drying the photosensitive thermosetting developable two-component resin composition of the present invention onto a carrier film. When forming the dry film, first, the first and second components (i.e., the main component composition and the curing agent composition) of the photosensitive thermosetting developable two-component resin composition of the present invention are thoroughly mixed together. Then, the mixed composition is applied to the carrier film to a uniform thickness using a comma coater, blade coater, lip coater, bar coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, etc. The applied composition is then dried at a temperature of 50 to 130°C for 1 to 30 minutes to form the resin layer. There are no particular restrictions on the coating film thickness, but generally, the film thickness after drying is appropriately selected within the range of 10 to 150 μm, preferably 20 to 60 μm.

[0081] As the carrier film, a plastic film is used, such as polyester film (e.g., polyethylene terephthalate (PET)), polyimide film, polyamide-imide film, polypropylene film, or polystyrene film. There are no particular restrictions on the thickness of the carrier film, but it is generally selected appropriately within the range of 10 to 150 μm.

[0082] After forming a resin layer made of the composition of the present invention on a carrier film, it is preferable to further laminate a peelable cover film on the surface of the resin layer for purposes such as preventing dust from adhering to the surface of the resin layer. Examples of peelable cover films that can be used include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper. The cover film should have less adhesive strength to the resin layer than the carrier film when the cover film is peeled off.

[0083] In addition, in the present invention, a resin layer can be formed by applying and drying the composition of the present invention on the cover film, and a carrier film can be laminated on its surface. That is, when manufacturing a dry film in the present invention, either a carrier film or a cover film may be used as the film to which the composition of the present invention is applied.

[0084] Here, the photosensitive thermosetting developable two-component resin composition of the present invention can be adjusted to a viscosity suitable for the coating method using a high-boiling point solvent, and then applied to a substrate by methods such as dip coating, flow coating, roll coating, bar coating, screen printing, or curtain coating. After application, the high-boiling point solvent contained in the composition can be evaporated and dried (pre-dried) at a temperature of approximately 60 to 100°C to form a tack-free resin layer. Furthermore, in the case of a dry film in which the composition is applied to a carrier film or cover film, dried, and wound as a film, the resin layer can be formed by laminating the layer of the composition of the present invention onto the substrate using a laminator or the like so that it comes into contact with the substrate, and then peeling off the carrier film.

[0085] Examples of the aforementioned substrates include printed circuit boards and flexible printed circuit boards with circuits pre-formed using copper, etc., as well as copper-clad laminates of all grades (FR-4, etc.) using materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / nonwoven fabric epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, copper-clad laminates for high-frequency circuits using fluororesin, polyethylene, polyphenylene ether (polyphenylene oxide), cyanate, etc., and metal substrates, polyimide films, PET films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafers, etc.

[0086] cured product 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, and after the solvent has evaporated and dried, the resulting resin layer is exposed (irradiated with light) to cure the exposed area (the part that has been irradiated with light). Specifically, the resin layer is selectively exposed with active energy rays through a photomask with a pattern formed on it using a contact or non-contact method, or the pattern is directly exposed using a laser direct exposure machine, and the unexposed areas are developed with an alkaline aqueous solution (for example, a 0.3-3% by mass sodium carbonate aqueous solution) to form a resist pattern. Furthermore, by heating to a temperature of approximately 100-180°C and performing thermal curing (post-curing), a cured film (cured product) with excellent properties such as heat resistance, chemical resistance, moisture resistance, adhesion, and electrical properties can be formed.

[0087] The volatilization drying or thermal curing during the formation of the cured product can be carried out using, for example, a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, etc. (a method of bringing hot air in the dryer into countercurrent contact using a device equipped with a steam-heated air source, and a method of blowing hot air onto the support from a nozzle).

[0088] Furthermore, the exposure machine used for the activated energy ray irradiation can be any device equipped with a high-pressure mercury lamp, ultra-high-pressure mercury lamp, metal halide lamp, mercury short-arc lamp, etc., that irradiates ultraviolet light in the range of 350 to 450 nm. In addition, a direct writing device (for example, a laser direct imaging device that directly draws patterns with a laser using CAD data from a computer) can also be used. The lamp light source or laser light source of the direct writing device can have a maximum wavelength in the range of 350 to 410 nm. The exposure amount for pattern formation varies depending on the film thickness, etc., but is generally 20 to 1000 mJ / cm². 2 Preferably 20-800 mJ / cm² 2 It can be set to the range of

[0089] Next, in the development step, the dried coating film after the exposure step is treated with a developer solution. In this way, the unexposed portions of the coating film are removed, and a patterned film of the curable composition of the present invention is formed.

[0090] Here, the dipping method, shower method, spray method, brush method, etc., can be used as the developing process. Typically, a sodium carbonate aqueous solution with a mass concentration of 0.5 to 5% can be used as the developer, but other alkaline aqueous solutions such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium silicate, ammonia, and amines can also be used.

[0091] In this developing process, the developer solution temperature is 20-40°C and the developing time is 180 seconds or less.

[0092] During this development process, the resulting pattern film may be washed with a rinsing solution as needed. Distilled water, methanol, ethanol, isopropyl alcohol, etc., can be used as the rinsing solution, either alone or in combination.

[0093] Printed circuit board Furthermore, the present invention can provide a printed circuit board having the cured product. The photosensitive 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.

[0094] The present invention will be described in more detail below based on examples and comparative examples. However, the technical scope and embodiments of the present invention are not limited thereto. In the examples and comparative examples, "parts" or "%" are based on weight unless otherwise specified. The property values ​​of the compositions in these examples were tested by the method described below. [Examples]

[0095] [Synthesis example: Synthesis of carboxyl group-containing vinyl ester resin] 214 parts of cresol novolac type epoxy resin EPICLON N-695 (manufactured by DIC, epoxy equivalent = 214) were placed in a four-necked flask equipped with a stirrer and reflux condenser. 103 parts of carbitol acetate and 103 parts of petroleum hydrocarbon solvent (manufactured by Japan Energy Corporation, trade name: Cactus Fines SF-01) were added and heated until dissolved. Next, 0.1 parts of hydroquinone as a polymerization inhibitor and 2.0 parts of triphenylphosphine as a reaction catalyst were added. 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 mg KOH / g.

[0096] Using the carboxyl group-containing vinyl ester resin solution (varnish) from the above synthesis example, various components and proportions (parts by weight) shown in Table 1 were blended, pre-mixed with a stirrer, and then kneaded in a three-roll mill to prepare a photosensitive thermosetting developable two-component resin composition. Furthermore, the drying range, acid resistance, metal plating resistance, high-temperature storage capacity, volatile matter, and discoloration resistance were evaluated by the following methods.

[0097] [Table 1]

[0098] "ND" indicates that the result was below the detection limit and no detection was found. Each component listed in Table 1 is explained as follows. * 1: Carboxyl group-containing vinyl ester resin obtained in the synthesis example, solids content 65%, solvent 35% * 2: Pigment: 6Y-501, manufactured by TOYOCOLOR CO., LTD. * 3. Additives: KS-66 (manufactured by Shin-Etsu Chemical Co., Ltd.), BYK-1790 (manufactured by BYK (Shanghai) Co., Ltd.) * 4: Initiator: ITX, isopropylthioxanthone (manufactured by DKSH JAPAN), #907: α-aminoacetophenone-based photoinitiator (Omnirad 907 manufactured by IGM Resins) * 5: Filler: B-30, manufactured by Sakai Chemical Industry Co., Ltd., A-8, manufactured by Sibelcon * 6: Solvent: DPM: dipropylene glycol monomethyl ether, manufactured by Taiwan Lyondell * 7: Melamine: MELAMINE-JC, manufactured by Jiangsu Jinxiang Sairui Chemical * 8: Melamine phthalate: THPAMELAMINESALT, manufactured by Shikoku Kasei Kogyo Co., Ltd. * 9: Epoxy resin: N-770, manufactured by DIC, novolak-type polyfunctional epoxy resin, solid content 100% * 10: Photosensitive monomer: DPHA, dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd.

[0099] Regarding the photosensitive thermosetting developable two-component resin compositions of the above Examples and Comparative Examples, after mixing the first agent and the second agent, the following tests were conducted.

[0100] <Drying control range (time from after drying until exposure and development are possible)> Each composition described in Table 1 was entirely coated on a copper foil substrate with a pattern formed thereon by screen printing, and dried in a hot air circulation drying oven at 80°C. After the start of drying, the substrate was taken out every 10 minutes from 20 minutes to 70 minutes, and gradually cooled to room temperature. For this substrate, using a 1 wt% aqueous sodium carbonate solution at 30°C, development was carried out for 60 seconds at a spray pressure of 0.2 MPa, and the maximum allowable drying time without residue remaining was defined as the drying control range.

[0101] ○: The maximum allowable drying time without residue remaining is 50 minutes or more. ×: The maximum allowable drying time without residue remaining is less than 50 minutes.

[0102] <Acid resistance> Each composition listed in Table 1 was screen-printed onto a substrate with a 2 mm copper wire pattern 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, and then curing in a hot air circulating drying oven at 150°C for 60 minutes. The cumulative exposure amount in the UV transport oven was 2000 mJ / cm². 2 The evaluation substrate was fabricated by irradiating it with ultraviolet light under these conditions.

[0103] The evaluation substrate was immersed in a 10 vol% H2SO4 aqueous solution at room temperature for 20 minutes, and this process was repeated a total of five times. The elution of the impregnated and cured coating was visually confirmed, and peeling due to tape removal was also checked. ○: No change observed. △: Only a slight change. ×: The paint film blistered or swelled and peeled off.

[0104] <Metal Plating Resistance> A separate evaluation substrate was prepared using the same manufacturing method as the evaluation substrate described in <Acid Resistance> above. Using this evaluation substrate, plating was performed using commercially available electroless nickel plating baths and electroless gold plating baths under conditions of nickel 0.5 μm and gold 0.03 μm. The presence or absence of plating penetration was evaluated, and then the presence or absence of peeling of the cured coating film was evaluated by tape peeling. The judgment criteria are as follows.

[0105] ○: No penetration or peeling is observed. △: Slight penetration was observed after plating, and peeling was observed after tape removal. ×: Peeling occurred after plating.

[0106] <High-temperature storage capacity (TS test)> A separate evaluation substrate was prepared using the same manufacturing method as the evaluation substrate described in the section on acid resistance above. This evaluation substrate was placed in a 160°C oven and left for slightly different durations, and a grid test was performed as follows. The maximum number of hours without detachment during the grid test was recorded.

[0107] Grid pattern test: After post-baking, a grid pattern was drawn on the hardened coating surface using a completely new blade, applying a force at a 30° angle to the board surface. A peel test was then performed using 3M tape. The evaluation criteria are as follows:

[0108] ○: No detachment occurred during high-temperature storage for over 1000 hours in the grid test. ×: High-temperature storage time without detachment in the grid test is less than 1000 hours.

[0109] <Volatile Matter Evaluation> A separate evaluation substrate was prepared using the same manufacturing method as the evaluation substrate described in the section on acid resistance above. The cured coating film of this evaluation substrate was pretreated in accordance with US EPA3550C:2007, and the volatile matter content was analyzed using HPLC, GC-MC, and LC-MS-MS.

[0110] A lower amount of volatile matter measured by LC-MS / MS indicates less volatilization of harmful substances during soldering. In this invention, a volatile matter level of less than 1000 ppm is considered acceptable.

[0111] <Colorfastness> A separate evaluation substrate was prepared using the same manufacturing method as the evaluation substrate described in <Acid Resistance> above. For this evaluation substrate, the cured coating film L * a * b * The color was measured using a Konica Minolta CM-2600d spectrophotometer. Subsequently, heat treatment (i.e., accelerated degradation) was performed at 150°C for 2 hours, and L was measured using the same method. * a * b * The following was measured. From the measured value, ΔEab was calculated using the following formula. ΔEab=((L * 2-L * 1)2 +(a * 2-a * 1) 2 +(b * 2-b * 1) 2 ) 0.5 (In the formula, L * 1, a * 1, b * 1 is L before heat treatment * a * , b * It represents the value of L * 2, a * 2, b * 2 is L after heat treatment * a * , b * (Represents the value of.)

[0112] Here, ΔEab is L * a * b * This value is calculated as the difference between the initial value and the value after accelerated degradation in the color system. A larger value indicates that the system is more susceptible to oxidative discoloration and has lower discoloration resistance.

[0113] As is clear from the above, in Examples 1 to 4, by including an appropriate amount of melamine phthalate, it was possible to obtain melamine-free photosensitive thermosetting developable two-component resin compositions that were excellent in terms of drying control range, acid resistance, metal plating resistance, high-temperature storage performance, volatile matter, and discoloration resistance. In contrast, Comparative Example 1 contained neither melamine phthalate nor melamine, and the cured product obtained from the composition had poor acid resistance, metal plating resistance, and discoloration resistance. In Comparative Example 2, which had a low melamine content, and Comparative Example 7, which had an insufficient melamine phthalate content, acid resistance and metal plating resistance were slightly improved compared to Comparative Example 1, but still not sufficient, and discoloration resistance remained poor. In Comparative Examples 2 to 6, using a certain amount of melamine improved acid resistance, metal plating resistance, and discoloration resistance, but volatile matter increased significantly. Furthermore, in Comparative Example 6, which contained a large amount of melamine, and Comparative Example 8, which contained an excessive amount of melamine phthalate, the drying control range was poor and the amount of volatile matter was somewhat high.

[0114] These results demonstrate that the melamine-free photosensitive thermosetting two-component resin composition of the present invention exhibits excellent drying control range, reduces the volatilization of harmful substances during the soldering process, and yields cured products with excellent acid resistance, metal plating resistance, high-temperature storage properties, and discoloration resistance. The melamine-free photosensitive thermosetting two-component resin composition of the present invention, the dry film using the same, and their cured products can be suitably used as solder resists for printed circuit boards.

Claims

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

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

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 agent.

4. (E) The melamine-free photosensitive thermosetting developable two-component resin composition according to claim 1 or 2, further comprising 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 agent.

6. (F) The melamine-free photosensitive thermosetting developable two-component resin composition according to claim 1 or 2, further comprising a photosensitive monomer.

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 agent.

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

9. A melamine-free photosensitive thermosetting developable two-component resin composition according to claim 1 or 2, characterized in that it is used in solder resist.

10. A dry film comprising a carrier film and a resin layer obtained by applying and drying a melamine-free photosensitive thermosetting developable two-component resin composition according to any one of claims 1 to 9 onto the carrier film.

11. A cured product characterized by being obtained by curing a melamine-free photosensitive thermosetting developable two-component resin composition according to any one of claims 1 to 9.

12. A cured product characterized by being obtained by curing the resin layer of the dry film described in claim 10.

13. A printed circuit board characterized by having the cured product described in claim 11 or 12.

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