TW202104335A - Curable resin composition, cured product, acid-modified maleimide resin, and curing agent - Google Patents

Abstract

The objective of the present invention is to provide: an acid-modified maleimide resin from which a cured product having excellent alkali developability and heat resistance can be obtained, and a curable resin composition including said resin; and a dry film and a printed wiring board using a solder resist forming composition and said curable resin composition; and a printed wiring board using the curable resin composition. The present invention uses a curable resin composition comprising: an acid-modified maleimide resin (A) containing a structure (1) obtained by adding, to an N-substituted maleimide group, a conjugated diene-containing fatty acid or a derivative (a1) thereof; and a curable resin (B). The acid-modified maleimide resin (A) preferably has, in one molecule, at least two structures represented by structural formula (i) [in formula (i), R is a hydrogen atom or an aliphatic hydrocarbon group having 1-20 carbon atoms, and X is a direct bond or a divalent aliphatic hydrocarbon group having 1-20 carbon atoms.].

Description

Curable resin composition, cured product, acid-modified maleimide resin and curing agent

The present invention relates to an acid-modified maleimide resin, a curing agent, and a curable resin composition containing the curing agent. Specifically, it relates to the curability of the solder resist used in the formation of printed circuit boards. Resin composition, and dry film and printed circuit board using it.

In recent years, in response to the increase in density of printed circuit boards that have been accompanied by the reduction in lightness, thickness, and size of electronic machines, curable resin compositions for resin insulating layers such as solder resist layers have also been required to improve performance and workability. improve. Especially in automobiles, the electronic control system of the driving part has progressed, and printed circuit boards are often installed in places with high ambient temperature such as the engine room and its surroundings. Automotive printed circuit boards are exposed to high temperatures ranging from 80°C to 150°C for a long time depending on where they are loaded. Therefore, high-performance solder masks used in automotive printed circuit boards are required to have excellent heat resistance.

As far as materials suitable for such solder resist layers are concerned, bismaleimide compounds can be cited. Although the bismaleimide compound is a resin with excellent heat resistance, flame resistance, and dielectric properties, it is a well-known bismaleimide compound that does not exhibit curing reactivity with epoxy resin. In the case of using a curable resin of a curable system in combination, there is a problem of insufficient heat resistance. Therefore, an amine-modified bismaleimide compound obtained by reacting the amine group of a monoamine compound such as aminophenol with the unsaturated N-substituted maleimide group of the bismaleimide compound is proposed , A proposal to use together with a curable resin of an epoxy curing system (for example, refer to Patent Document 1). However, due to the insufficient alkali developability of the compound, it is still insufficient as a solder resist material, especially for the solder resist material sought for in printed circuit boards with miniaturized circuits in recent years.

In addition, it has also been proposed to use a bismaleimide compound obtained by modifying an amine compound having a carboxyl group such as aminobenzoic acid in combination with a curable epoxy resin (for example, refer to Patent Document 2). However, the compound has a low thermal decomposition temperature and is still insufficient in the heat resistance to lead-free solder required in recent years. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2012-166515 A [Patent Document 2] JP 2007-302843 A

[The problem to be solved by the invention]

Therefore, the problem to be solved by the present invention is to provide an acid-modified maleimide resin that can obtain a cured product excellent in alkali developability and heat resistance, and a curable resin composition containing the resin, and a solder resist layer formation. Composition, and dry film and printed circuit board using the above-mentioned curable resin composition. [Means to solve the problem]

As a result of various studies conducted by the inventors, they found that by using the Diels-Alder reaction to add fatty acids with conjugated diene to the N- in the maleimide resin The acid-modified maleimide resin formed by substituting the maleimide group as a hardener can obtain a hardened product with excellent heat resistance and good alkali developability, thus solving the above-mentioned problems.

That is, the present invention provides a curable resin composition characterized by comprising an acid-modified maleimide resin (A) and a curable resin (B), wherein the acid-modified maleimide resin (A) Containing structure (1), the structure (1) is formed by adding a fatty acid with a conjugated diene or its derivative (a1) to an N-substituted maleimide group; the present invention also provides the curable resin The use of the composition, the hardened product, and the acid-modified maleimide resin with a specific structure suitable for use as a hardener. [Effects of Invention]

According to the present invention, it is possible to provide an acid-modified maleimide resin capable of obtaining a cured product excellent in heat resistance and alkali developability, and a curable resin composition containing the compound, a composition for forming a solder resist layer, and use Dry film and printed circuit board of the above-mentioned curable resin composition.

[Form to implement the invention]

The curable resin composition of the present invention is characterized by comprising an acid-modified maleimide resin (A) and a curable resin (B), and the acid-modified maleimide resin (A) contains the structure (1) ), the structure (1) is formed by adding a fatty acid with a conjugated diene or its derivative (a1) to the N-substituted maleimide group.

The aforementioned N-substituted maleimide group means an unsaturated N-substituted maleimide group called maleimide, that is, it is preferable to use maleimide as a raw material.

With regard to the aforementioned maleimines, for example, bismaleimines compounds having two maleimines in one molecule, and horses having three or more maleimines in one molecule can be cited. Leimine resin.

Regarding the aforementioned bismaleimide compound, as long as it is a compound having at least two unsaturated N-substituted maleimide groups in the molecular structure, any of them can be used. As a preferred one, for example, The bismaleimide compound represented by the following formula (a1) is exemplified:

[式(a1)中，R¹ 為具有芳香環或脂肪族烴的二價有機基]。該R¹ ，從所得到之硬化物中耐熱性優良的觀點而言，以具有芳香環之二價有機基為更佳。

[In the formula (a1), R ¹ is a divalent organic group having an aromatic ring or an aliphatic hydrocarbon]. This R ¹ is more preferably a divalent organic group having an aromatic ring from the viewpoint of excellent heat resistance in the obtained cured product.

Among them, the ^{divalent organic group having an aromatic ring or aliphatic hydrocarbon of R 1} includes alkylene, cycloalkylene, monocyclic or polycyclic arylalkylene, or their groups by A divalent group to which a divalent atomic group (for example, an alkylene group, a cyclic alkylene group, an oxygen atom, a sulfur atom, a sulfinyl group, a sulfinyl group, a disulfide group, a carbonyl group, etc.) is bonded is a preferred structure.

Regarding the aforementioned bismaleimide compound, specifically, N,N'-ethylene bismaleimide, N,N'-hexamethylene bismaleimide, N, N'-(1,3-phenylene) bismaleimide, N,N'-[1,3-(2-methylphenylene)] bismaleimide, N,N' -[1,3-(4-Methylphenylene)]bismaleimide, N,N'-(1,4-phenylene)bismaleimide, bis(4-maleimide) Aminophenyl) methane, bis(3-methyl-4-maleimidphenyl) methane, 3,3-dimethyl-5,5-diethyl-4,4-diphenyl Methane bismaleimide, bis(4-maleimidphenyl) ether, bis(4-maleimidphenyl) sulfide, bis(4-maleimidphenyl) sulfide , Bis(4-maleimidphenyl) ketone, bis(4-maleimidcyclohexyl)methane, 1,4-bis(4-maleimidphenyl)cyclohexane, 1 ,4-bis(maleimidyl)cyclohexane, 1,4-bis(maleimidyl)benzene, 1,3-bis(4-maleimidphenoxy) Benzene, 1,3-bis(3-maleiminophenoxy)benzene, bis[4-(3-maleiminophenoxy)phenyl]methane, bis[4-(4-male Leximinophenoxy)phenyl]methane, 1,1-bis[4-(3-maleimidinphenoxy)phenyl]ethane, 1,1-bis[4-(4- Maleimide phenoxy) phenyl] ethane, 1,2-bis[4-(3-maleimide phenoxy) phenyl] ethane, 1,2-bis[4-( 4-maleimidephenoxy)phenyl]ethane, 2,2-bis[4-(3-maleimidephenoxy)phenyl]propane, 2,2-bis[4- (4-Maleimidephenoxy)phenyl)propane, 2,2-bis[4-(3-maleimidephenoxy)phenyl)butane, 2,2-bis[4 -(4-maleimidephenoxy)phenyl]butane, 2,2-bis[[4-(3-maleimidephenoxy)phenyl]-1,1,1, 3,3,3-hexafluoropropane, 2,2-bis[4-(4-maleimide phenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 4,4-bis(3-maleimide phenoxy) biphenyl, 4,4-bis(4-maleimide phenoxy) biphenyl, bis[4-(3-maleimide phenoxy) Iminophenoxy) phenyl] ketone, bis[4-(4-maleiminophenoxy)phenyl] ketone, 2,2'-bis(4-maleiminophenyl) two Sulfide, bis(4-maleimidphenyl) disulfide, bis[4-(3-maleimidphenoxy)phenyl]sulfide, bis[4-(4-maleimide) Aminophenoxy) phenyl] sulfide, bis[4-(3-maleimidin phenoxy) phenyl] sulfide, bis[4-(4-maleimidin phenoxy) )Phenyl] arsenic, bis[4-(3-maleiminophenoxy)phenyl] arsenic, bis[4-(4-maleiminophenoxy)phenyl] arsenic, double [4-(3-Maleimide phenoxy) phenyl] ether, bis[4-(4-maleimide) Phenoxy) phenyl] ether, 1,4-bis[4-(4-maleimidin phenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4- (4-maleimidin phenoxy)-α,α-dimethylbenzyl)benzene, 1,4-bis[4-(3-maleimidin phenoxy)-α,α- Dimethylbenzyl]benzene, 1,3-bis[4-(3-maleiminophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-( 4-maleimide phenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-maleimide phenoxy) Yl)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-maleiminophenoxy)-3,5-dimethyl -Α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleiminophenoxy)-3,5-dimethyl-α,α-dimethyl Benzyl]benzene, 4-methyl-1,3-phenylene bismaleimide, polyphenylmethane maleimide, etc. These maleimide compounds can be used alone or Mix and use two or more types.

Among these, 2,2-bis[4-(4-maleiminophenoxy)phenyl]propane, bis(4-maleiminophenyl)methane, 4-methyl- 1,3-phenylene bismaleimide, polyphenylmethane maleimide, and bis(4-maleimide phenyl) are preferred. Furthermore, from the viewpoint of high reaction rate and higher heat resistance, bis(4-maleimidphenyl)methane, bis(4-maleimidphenyl), bis( 4-maleiminophenyl) sulfide, bis(4-maleiminophenyl) disulfide, N,N'-(1,3-phenylene) bismaleimide, 2,2-bis(4-(4-maleimidphenoxy)phenyl)propane is preferred. From the viewpoint of low cost, bis(4-maleimidphenyl)methane, N,N'-(1,3-phenylene) bismaleimide is more preferable. From the viewpoint of solvent solubility, bis(4-maleiminophenyl)methane is used as Especially good.

In addition, specific examples of maleimide resins having 3 or more N-substituted maleimide groups in one molecule include, for example, any of the following structural formulas (a2) to (a4) The person said.

(式中R² 互相獨立，為包含聚合性不飽和鍵之基、烷基、烷氧基、鹵素原子、芳基、芳烷基之任一者；R³ 為氫原子、烷基、鹵化烷基、鹵素原子之任一者；p為0或1～4之整數，q為0或1～3之整數；V為碳原子數1～4之伸烷基、芳基亞甲基、伸烷基伸芳基伸烷基、伸烷基伸聯苯基伸烷基、環伸烷基、氧原子、硫原子、羰基之任一者；Z為碳原子或氮原子； m為1以上之整數，n為3～6之整數)。

(In the formula, R ^{2 is} independent of each other and is any one of a group containing a polymerizable unsaturated bond, an alkyl group, an alkoxy group, a halogen atom, an aryl group, and an aralkyl group; R ³ is a hydrogen atom, an alkyl group, or an alkyl halide Any one of a group and a halogen atom; p is 0 or an integer of 1 to 4, q is an integer of 0 or 1 to 3; V is an alkylene, arylmethylene, or alkylene having 1 to 4 carbon atoms Any one of arylalkylene, biphenylene, cyclic alkylene, oxygen atom, sulfur atom, carbonyl group; Z is a carbon atom or a nitrogen atom; m is an integer of 1 or more, and n is 3 An integer of ~6).

Among these, it is preferable to use the resin represented by the aforementioned structural formula (a2) from the viewpoint of easy reaction control during acid modification and the viewpoint that the heat resistance of the cured product obtained is more excellent, especially It is more preferable to use a resin having V as an alkylene group having 1 to 4 carbon atoms, and having p and q as 0.

For these maleimines, commercially available ones can be used directly, for example, BMI series manufactured by Daiwa Chemical Industry Co., Ltd. (BMI-1000, 2000, 2300, 3000, 4000, 6000, 7000, 8000, TMH Etc.), BMI, BMI-70, BMI-80, etc. manufactured by KI Chemical Co., Ltd., B1109, B4807, P0778, P0976, etc. manufactured by Tokyo Chemical Industry Co., Ltd.

The fatty acid having a conjugated diene or its derivative (a1) used in the present invention, as long as it has a conjugated diene that can undergo Diels-Alder reaction with the aforementioned N-substituted maleimide group, and has The compound of a carboxyl group or its derivative is sufficient, and it does not specifically limit. In addition, the derivative means a compound in which the carboxyl group becomes a salt structure or a halide, which means a compound that does not hinder the Diels-Alder reaction and can become a carboxyl group after the addition reaction. From the viewpoint of easy control of the reaction, it is preferable to use fatty acid as a raw material.

As for the aforementioned fatty acids with conjugated diene, for example, sorbic acid, 2,4-decadienoic acid, 2,4-dodecadienoic acid, 10,12-octadecadienoic acid , 9-hydroxy-10,12-octadecadienoic acid, 13-hydroxy-9,11-octadecadienoic acid, 9,14-dihydroxy-10,12-octadecadienoic acid, 9 ,12,14-octadecatrienoic acid, 8,10,12-octadecatrienoic acid, oleonic acid, etc., or conjugated diene fatty acids formed by selectively hydrogenating fatty acids with various alkyl groups, It can be used alone or in combination of two or more kinds. Especially from the viewpoint of easy control of the addition reaction and better heat resistance of the obtained hardened product, it is better to use conjugated diene fatty acid with carbon number of 8 or less, if the ease of raw material acquisition is also considered , It is better to use sorbic acid.

The aforementioned Diels-Alder reaction is a well-known reaction and is not particularly limited in the present invention. For example, it can be carried out at a reaction temperature of 20 to 150°C and a reaction time of 1 to 80 hours. At this time, it is preferable to use the mol number of the fatty acid with a conjugated diene or its derivative (a1) in the range of 0.01 to 1.5 mol relative to 1 mol of the N-substituted maleimide group. , More preferably used in the range of 0.02 to 1.1 mol.

When performing the Diels-Alder reaction, an organic solvent can be used. As for the organic solvents that can be used, for example, alcoholic solvents such as ethanol, propanol, butanol, methyl cellophane, butyl cellophane, and propylene glycol monomethyl ether; acetone, methyl ethyl Ketone solvents such as ketone, methyl isobutyl ketone, and cyclohexanone; ether solvents such as tetrahydrofuran; aromatic solvents such as toluene, xylene, mesitylene; solvents containing S atoms such as dimethyl sulfide; two Methylformamide, dimethylacetamide, N-methylpyrrolidone and other solvents containing N atoms; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether Diethylene glycol dialkyl ethers; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol Polyethylene glycol dialkyl ethers such as diethyl ether and triethylene glycol dibutyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono Ethylene glycol monoalkyl ether acetates such as butyl ether acetate; diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether Polyethylene glycol monoalkyl ether acetate, such as acetate, triethylene glycol monomethyl ether acetate, triethylene glycol monoethyl ether acetate, triethylene glycol monobutyl ether acetate, etc. Class; Propylene glycol dialkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, and propylene glycol dibutyl ether; dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dibutyl ether, tripropylene glycol Polypropylene glycol dialkyl ethers such as dimethyl ether, tripropylene glycol diethyl ether, and tripropylene glycol dibutyl ether; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether Propylene glycol monoalkyl ether acetates such as acetate; dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol monobutyl ether acetate, tripropylene glycol monomethyl ether Acetate, tripropylene glycol monoethyl ether acetate, tripropylene glycol monobutyl ether acetate and other polypropylene glycol monoalkyl ether acetates; low molecular ethylene-propylene copolymers and other copolymerized polyether glycols Dialkyl ethers; monoacetate monoalkyl ethers of copolymerized polyether glycols; alkyl esters of copolymerized polyether glycols; and monoalkyl esters and monoalkyls of copolymerized polyether glycols Ethers and so on. These organic solvents can be used singly or in combination of two or more kinds. Among these, from the viewpoint of suppressing side reactions, a solvent that does not contain an alcoholic hydroxyl group is preferred. Furthermore, from the viewpoint of solubility, ketone-based solvents such as cyclohexanone and methyl ethyl ketone, and ester-based solvents are preferred. The amount of organic solvent used is not particularly limited. It is usually 0.5-100 parts by mass relative to the total mass of maleimine and the fatty acid with conjugated diene or its derivative (a1) (a1) as the raw material. Parts by mass are preferably 0.5 to 70 parts by mass, more preferably 0.5 to 50 parts by mass.

The acid-modified maleimide resin (A) in the present invention is obtained by the aforementioned addition reaction, and preferably has a structure represented by the following structural formula (1) in the molecule:

[式(i)中，R為氫原子或碳原子數1～20之脂肪族烴基，X為直接鍵結或碳原子數1～20之二價脂肪族烴基]，尤其，從所得到之硬化物耐熱性的觀點而言，以1分子中具有2個以上該結構為更佳。

[In formula (i), R is a hydrogen atom or an aliphatic hydrocarbon group with 1 to 20 carbon atoms, and X is a direct bond or a divalent aliphatic hydrocarbon group with 1 to 20 carbon atoms], especially from the resulting hardened From the viewpoint of physical heat resistance, it is more preferable to have two or more such structures in one molecule.

Especially when the aforementioned bismaleimide resin is used, it is preferably a resin represented by the following structural formula (ii):

[式(ii)中，R¹ 為具有芳香環或脂肪族烴之二價有機基，R為氫原子或碳原子數1～20之脂肪族烴基，X為直接鍵結或碳原子數1～20之二價脂肪族烴基]。

[In formula (ii), R ¹ is a divalent organic group having an aromatic ring or an aliphatic hydrocarbon, R is a hydrogen atom or an aliphatic hydrocarbon group with 1 to 20 carbon atoms, and X is a direct bond or a carbon number of 1 to 20 bis divalent aliphatic hydrocarbon group].

Furthermore, when the maleimide resin represented by the aforementioned structural formula (a2) is used as a raw material, it is preferably a resin represented by the following structural formula (iii):

[式(iii)中，R為氫原子或碳原子數1～20之脂肪族烴基，X為直接鍵結或碳原子數1～20之二價脂肪族烴基，s為0～10之整數，t為0～10之整數，且s+t為2以上。但是，重覆結構可為無規則，亦可為嵌段，在s為1以上之情況，亦可為末端未進行酸改性之結構]。此等之中，從所得到之硬化物耐熱性的觀點而言，尤其較佳為：具有共軛二烯之脂肪酸或其衍生物(a1)之加成比率，相對於1莫耳之N-取代馬來醯亞胺基為0.02～1莫耳之樹脂。

[In formula (iii), R is a hydrogen atom or an aliphatic hydrocarbon group with 1-20 carbon atoms, X is a direct bond or a divalent aliphatic hydrocarbon group with 1-20 carbon atoms, s is an integer of 0-10, t is an integer of 0-10, and s+t is 2 or more. However, the repeating structure may be random or block, and when s is 1 or more, it may be a structure without acid modification at the end]. Among these, from the viewpoint of the heat resistance of the cured product obtained, it is particularly preferable that the addition ratio of the fatty acid having a conjugated diene or its derivative (a1) relative to 1 mol of N- The substituted maleimide group is 0.02 to 1 mol resin.

The acid-modified maleimide resin (A) of the present invention obtained in this way usually shows a colorless to brown solid resin or liquid state, and crystallizes as the case may be.

In the case where the hue of the acid-modified maleimide resin in the present invention is different, the hue can also be improved by hydrogenation in the presence of a hydrogenation catalyst. The hydrogenation catalyst used at this time is preferably one containing iron group elements such as nickel or platinum group elements such as palladium, rhodium, and platinum as the active ingredient, and more preferably one that maintains the active ingredient on the carrier.

In addition, the carboxyl equivalent of the acid-modified maleimide resin in the present invention is not particularly limited. However, when used as a curing agent described later, from the viewpoint of the heat resistance of the cured product obtained, 200 to 10,000 [g The range of /eq] is preferred. Furthermore, from the viewpoint of the alkali developability of the blend, the range of 350 to 2000 [g/eq] is preferred.

In addition, the molecular weight of the acid-modified maleimide resin in the present invention is not particularly limited. However, when used as a curing agent described later, from the viewpoint of shortening the molding time of the cured product and imparting an arbitrary shape, the weight The average molecular weight is preferably 300 to 10,000, and more preferably 330 to 5,000. The weight average molecular weight is a polystyrene conversion value measured in accordance with the method described in the examples.

The acid-modified maleimide resin can be used as a hardening agent for the curable resin, for example, it can be used with the following components.

Regarding the curable resin (B) used in the present invention, as long as it is a resin that exhibits curability by heating or active energy rays, it can be used without particular limitation. For example, epoxy resin, melamine resin, and benzoic acid can be exemplified. Amino resins such as guanamine resins, melamine derivatives, benzoguanamine derivatives, blocked isocyanate compounds, cyclic carbonate compounds, polyfunctional oxetane compounds, cyclic sulfide resins, bismaleimides, Well-known curable resins such as carbodiimide resins and cyanate ester resins are preferable, and among them, epoxy resins are preferable.

More specifically, epoxy resins include novolac resin type epoxy resins, bisphenol A type epoxy resins, biphenyl type epoxy resins, triphenylmethane type epoxy resins, and phenol aralkyl type epoxy resins. Oxygen resin and so on. Specifically, examples include: bisphenol A, bisphenol S, thiodiol, bisphenol, terpene diol, 4,4'-biphenol, 2,2'-biphenol, 3,3',5, 5'-Tetramethyl-[1,1'-biphenyl]-4,4'-diol, hydroquinone, resorcinol, naphthalenediol, ginseng (4-hydroxyphenyl) methane, 1,1 , 2,2-(4-hydroxyphenyl)ethane, phenols (phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.) and formaldehyde , Acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, o-hydroxybenzaldehyde, p-hydroxyacetophenone, o-hydroxyacetophenone, dicyclopentadiene, furfural, 4,4'-bis(chloromethyl)-1 ,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxy) (Methyl) benzene and other polycondensates and their modified products, halogenated bisphenols such as tetrabromobisphenol A, glycidyl ether compounds derived from alcohols, alicyclic epoxy resins, and epoxy propylene Amine-based epoxy resin, glycidyl ester-based epoxy resin, silsesquioxane-based epoxy resin (silicone in a chain, cyclic, trapezoidal shape, or a mixed structure of at least two of them The oxane structure has a solid or liquid epoxy resin such as epoxy propyl group and/or epoxy cyclohexane structure, but it is not limited thereto.

In the curable resin composition of the present invention, the composition ratio of the acid-modified maleimide resin (A) to the curable resin (B) is not particularly limited, but from the viewpoint of excellent heat resistance and moisture resistance In the case of using an epoxy resin, the epoxy group of the curable resin (B) is preferably in the range of 1.0 to 2.0 equivalent relative to 1 equivalent of the carboxyl group of the acid-modified maleimide resin (A). Furthermore, from the viewpoint of alkali developability, it is more preferably in the range of 1.0 to 1.5 equivalents.

In the curable resin composition of the present invention, a well-known photopolymerization initiator (C) can be suitably added as necessary. As the photopolymerization initiator, a photopolymerization initiator selected from an oxime ester-based photopolymerization initiator having an oxime ester group, an alkylphenone-based photopolymerization initiator, and α-aminoacetophenone-based photopolymerization can be suitably used. One or more photopolymerization initiators in the group of initiators, phosphine oxide-based photopolymerization initiators, and titanium-based photopolymerization initiators.

In the case of using such an oxime ester-based photopolymerization initiator, the blending amount is excellent in photocurability and resolution, and the adhesion and PCT resistance are also improved. In addition, chemical resistance such as electroless gold plating resistance is also improved. From the viewpoint of an excellent solder resist layer, it is preferably 0.01 to 5% by mass of the entire composition, and more preferably 0.25 to 3% by mass.

In the case of using the alkylphenone-based photopolymerization initiator, from the same point of view, the blending amount is preferably 0.2-30% by mass of the entire composition, and more preferably 2-20% by mass. good.

In the case of using an α-aminoacetophenone-based photopolymerization initiator or an phosphine oxide-based photopolymerization initiator, the blending amount is 0.1-25 of the total composition from the same point of view The mass% is more preferable, and it is more preferable to be 1 to 20 mass %.

Moreover, as a photopolymerization initiator, Irgacure 389 manufactured by BASF Japan can also be suitably used. The preferable blending amount of Irgacure 389 is 0.1-20% by mass of the entire composition, and more preferably 1-15% by mass.

In addition, titanium-based photopolymerization initiators such as Irgacure 784 can also be suitably used. The preferred blending amount of the titanium-based photopolymerization initiator is 0.01 to 5 mass% of the entire composition, and more preferably 0.01 to 3 mass%.

By adjusting these photopolymerization initiators to a better blending amount, it can be formed with excellent photocurability and resolution, improved adhesion and PCT resistance, and excellent chemical resistance such as electroless gold plating resistance. Solder mask.

(thioxanthone)化合物、縮酮化合物、二苯基酮化合物、3級胺化合物、及氧蒽酮(xanthone)化合物等。In the curable resin composition of the present invention, in addition to the photopolymerization initiator, a photoinitiator and a sensitizer may be further used as needed. As for the photoinitiator and sensitizer that can be suitably used in the curable resin composition, benzoin compounds, acetophenone compounds, anthraquinone compounds, 9-oxothionin

(thioxanthone) compound, ketal compound, diphenyl ketone compound, tertiary amine compound, xanthone compound, etc.

These photo-initiating assistants and sensitizers can be used alone or in a mixture of two or more kinds. The total amount of the photo-initiating auxiliary agent and the sensitizer is preferably 30% by mass or less of the entire composition. If it exceeds 30% by mass, the deep curability tends to decrease due to such light absorption.

In the curable resin composition, a diluent (D) may be appropriately added as necessary. As for the diluent (D), it is preferable to blend a compound having an ethylenically unsaturated group in the molecule. The compound having an ethylenically unsaturated group in the molecule is photocured by the irradiation of active energy rays, thereby making the resin composition of the present invention insoluble in an alkaline aqueous solution, or helping it to be insoluble. For such compounds, commonly known polyester (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates, carbonate (meth)acrylates, Epoxy (meth)acrylates, specifically, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; ethylene glycol, methoxytetraethylene glycol, polyethylene Diacrylates of glycol, propylene glycol, etc.; N,N-dimethyl acrylamide, N-methylol acrylamide, N,N-dimethylaminopropyl acrylamide, etc. Amines; N,N-dimethylaminoethyl acrylate, N,N-dimethylaminopropyl acrylate and other amino alkyl acrylates; hexanediol, trimethylolpropane, new Polyols such as pentaerythritol, dineopentaerythritol, ginseng-hydroxyethyl isocyanurate or these ethylene oxide adducts, propylene oxide adducts, or ε-caprolactone additions Polyacrylates such as polyacrylates; phenoxy acrylate, bisphenol A diacrylate, and polyacrylates such as ethylene oxide adducts or propylene oxide adducts of these phenols; glycerol diglycidyl Polyacrylates of glycidyl ethers such as triglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, triglycidyl isocyanurate, etc.; not limited to the above , Can also include: directly acrylated polyols such as polyether polyol, polycarbonate diol, hydroxyl-terminated polybutadiene, polyester polyol, or urethane acrylated via diisocyanate Acrylates and melamine acrylates, and at least any one of methacrylates corresponding to the above-mentioned acrylates, and the like.

In addition, examples include epoxy acrylate resins obtained by reacting polyfunctional epoxy resins such as cresol novolac resin type epoxy resins with acrylic acid, or the hydroxyl groups of the epoxy acrylate resins, and neopentyl four An epoxy urethane acrylate compound formed by reacting a hydroxy acrylate such as alcohol triacrylate and a half urethane compound of a diisocyanate such as isophorone diisocyanate, or similarly with an acid anhydride Acid-modified epoxy acrylate resin containing carboxylic acid group formed by reaction. Such epoxy acrylate-based resins can improve the photocurability without reducing the dryness to the touch.

The compound having an ethylenically unsaturated group in the molecule as described above may be used alone or in combination of two or more kinds. Especially from the viewpoints of photoreactivity and resolution, a compound having 4 to 6 ethylenically unsaturated groups in one molecule is preferred, and if it is used, a compound having two ethylenically unsaturated groups in one molecule is used. The compound is preferable because the linear thermal expansion coefficient of the hardened material is reduced, and the occurrence of peeling during PCT is reduced.

When the diluent is used in the curable resin composition of the present invention, the blending amount is improved from the photocurability, the pattern formation becomes good by the alkali development after active energy ray irradiation, and the dissolution of the dilute alkali aqueous solution In terms of improved properties and a tendency to improve the impact resistance of the coating film, it is preferably 2-50% by mass of the entire composition.

In the curable resin composition of the present invention, a curing accelerator may be appropriately added as necessary. Examples of hardening accelerators include imidazoles such as 2-ethyl-4-methylimidazole and 1-methylimidazole; tertiary amines such as benzyldimethylamine and N,N-dimethylaniline ; Tetramethylammonium chloride, benzyltriethylammonium chloride and other quaternary ammonium salts; tetra-n-butylphosphonium-O,O-diethyldithiophosphonate, tetrabutylphosphonium benzotriazole Phosphonium salts such as salt; metal salts such as zinc octoate and zinc stearate; metal complexes such as zinc acetylacetonate and zinc benzylacetone.

In the case of using a hardening accelerator in the curable resin composition of the present invention, the blending amount is preferably 0.01 to 8% by mass, and more preferably 0.1 to 5% by mass. If the blending amount of the hardening accelerator is 0.01% by mass or more, since a sufficient effect can be obtained, it is preferable. In addition, if the blending amount of the hardening accelerator is 8% by mass or less, since the transparency and heat resistance of the obtained hardened product can be maintained, it is preferable.

In the curable resin composition of the present invention, an inorganic filler may be appropriately added as necessary. The inorganic filler is used in order to suppress the curing shrinkage of the cured product of the curable resin composition and to improve the properties such as adhesion and hardness. As for inorganic fillers, for example, barium sulfate, barium titanate, amorphous silica, crystalline silica, Neuenberg silica, fused silica, spherical silica, talc, clay, magnesium carbonate, Calcium carbonate, alumina, aluminum hydroxide, silicon nitride, aluminum nitride, etc.

The average particle diameter of the above-mentioned inorganic filler is preferably 5 μm or less. The blending ratio is preferably 75% by mass or less of the entire composition, and more preferably 0.1 to 60% by mass. If the blending ratio of the inorganic filler exceeds 75% by mass, the viscosity of the composition may increase, the coatability may decrease, or the cured product of the curable resin composition may become brittle.

In the curable resin composition of the present invention, it is also possible to further blend: organic solvents; elastomers; mercapto compounds; colorants; antioxidants; ultraviolet absorbers; adhesion promoters; polymerization inhibitors; Bentonite, montmorillonite and other viscosity-increasing agents; at least one of defoamers and leveling agents such as polysiloxane, fluorine, and polymer; and silane couples of imidazole, thiazole, triazole, etc. Mixtures; rust inhibitors; flame retardants such as phosphorus compounds such as phosphonates, phosphate derivatives, and phosphazene compounds; and well-known additives such as block copolymers as optional components.

In the curable resin composition of the present invention, an organic solvent can be used for the preparation of the above-mentioned resin composition or for adjusting the viscosity of the coating on the substrate and the carrier film. Such organic solvents for the preparation of the above-mentioned resin composition or for the viscosity adjustment of the substrate and the carrier film include ketones, aromatic hydrocarbons, glycol ethers, and glycol ether acetates. Types, esters, alcohols, aliphatic hydrocarbons, petroleum-based solvents, etc. In more detail, for example, ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; cellophane, methyl cellophane, and butyl Cellulose, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether, etc. Alcohol ethers; ethyl acetate, butyl acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol butyl ether acetate and other esters; ethanol, Alcohols such as propanol, ethylene glycol, and propylene glycol; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, naphtha, hydrogenated naphtha, mineral spirits, etc. Such an organic solvent may be used individually by 1 type, and may use 2 or more types as a mixture.

The dry film of the present invention has a curable resin layer formed by coating and drying the curable resin composition of the present invention. The dry film of the present invention can be used by laminating a curable resin layer so as to be adjacent to the base material.

The dry film of the present invention can be formed by uniformly coating the curable resin composition on a carrier film by a suitable method such as a knife coater, a lip coater, a comma coater, a film coater, etc., and drying it to form The aforementioned curable resin layer is preferably produced by laminating a cover film thereon. The cover film and the carrier film can be the same film material, or different films can be used.

In the dry film of the present invention, the film material of the carrier film and the cover film, as far as the dry film is used, can be any of well-known materials.

As the carrier film, a thermoplastic film such as a polyester film such as polyethylene terephthalate having a thickness of 2 to 150 μm can be used.

As for the cover film, a polyethylene film, a polypropylene film, etc. can be used, but it is preferable that the adhesive force with the curable resin layer is smaller than that of the carrier film.

The thickness of the curable resin layer on the carrier film of the present invention is preferably 100 μm or less, and more preferably in the range of 5-50 μm.

The printed circuit board of the present invention is preferably produced using the curable resin layer of the present invention constituting the dry film of the present invention. For example, it is preferable to form a resin insulating layer by laminating a dry film including a curable resin layer and heating it at a temperature of, for example, about 140 to 180° C. to heat it.

Furthermore, in the printed circuit board of the present invention, the curable resin composition can be directly coated on the substrate by a suitable method such as a knife coater, a lip coater, a comma coater, and a film coater, and then dried , The resin insulation layer is formed.

The resin insulating layer of the printed circuit board of the present invention can be patterned by irradiating _{semiconductor lasers such as CO 2} lasers and UV-YAG lasers. In addition, the holes can be made by CO ₂ laser, UV-YAG laser or drilling. When the resin insulating layer contains multiple layers, the hole can be made into a through hole that can communicate with any layer of the resin insulating layer, or a partial hole for the purpose of conducting the inner circuit and the surface of the resin insulating layer ( conformal via).

After the hole is drilled, in order to remove the smear on the inner wall and bottom of the hole, and to show the anchoring effect with the conductor layer (the metal plating layer formed later), a rough surface with fine unevenness is formed on the surface For the purpose of treatment, it is processed by commercially available desmear liquid (roughening agent) or liquid containing permanganate, dichromate, ozone, hydrogen peroxide/sulfuric acid, nitric acid and other oxidants .

Then, a circuit is formed by the subtractive method and the semi-additive method on the hole where the residue has been removed with the scum removal solution, or the surface of the film that has been roughened into a fine concave-convex shape. In either method, after performing electroless plating or electrolytic plating, or after these two types of plating, the purpose is to remove the stress of the metal and increase the strength, and perform it at about 80°C to 180°C for about 10 minutes to 60 minutes The heat treatment (annealing (annealing) treatment).

As for the metal plating used here, it can be copper, tin, solder, nickel, etc., and is not particularly limited, and a plurality of types can be used in combination. In addition, the electroplating used here can also be replaced by metal spattering.

In addition, when the resin insulating layer is formed by a photosensitive curable resin layer or a dry coating film formed by applying and drying a curable resin composition, the curable resin layer formed on the base material (substrate) Or dry the coating film, by contacting (or non-contacting), through a patterned photomask, selectively exposing with active energy rays or direct pattern exposing with a laser-guided exposure machine. The exposed part (the part irradiated with active energy rays) of the curable resin layer or the dried coating film will harden.

For the exposure machine used for active energy ray irradiation, a direct drawing device (for example, a laser-guided image processing device that draws an image directly with a laser using CAD data from a computer) and a metal halide lamp can be used Exposure machine, exposure machine equipped with (ultra) high pressure mercury lamp, exposure machine equipped with LED, exposure device equipped with mercury short arc lamp.

As for active energy rays, it is preferable to use light with a maximum wavelength in the range of 350 to 410 nm. By adjusting the maximum wavelength to this range, radicals can be efficiently generated from the photopolymerization initiator. In addition, the amount of exposure varies depending on the film thickness, etc. However, it can generally be set to 5 to 500 mJ/cm ² , and preferably set to be in the range of ^{10 to 300 mJ/cm 2.}

As for the direct drawing device, for example, those manufactured by Orbotech Co., Ltd., Pentax Co., Ltd., OAK Co., Ltd., and Dainippon Screen Co., Ltd. can be used, as long as the maximum irradiation wavelength is 350～ For devices with 410nm active energy rays, any device can be used.

Then, by exposing the curable resin layer and the dry coating film in this way, the exposed part (the part irradiated by the active energy ray) is cured, and the unexposed part is treated with a dilute alkali aqueous solution (for example, 0.3-3wt % Sodium carbonate aqueous solution) is developed, and a pattern is formed on the curable resin layer and the dried coating film.

At this time, as for the development method, the dipping method, washing method, spray method, painting method, etc. can be followed. In addition, as the developer, alkaline aqueous solutions such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, etc. can be used.

Furthermore, by heating the curable resin layer at a temperature of, for example, about 140-180°C, the carboxyl group of the acid-modified maleimide resin (A) reacts with the curable resin (B) to form a heat-resistant resin layer. A resin insulating layer (pattern) with excellent properties such as durability, chemical resistance, moisture absorption resistance, adhesion, and insulation reliability.

The total film thickness of the resin insulating layer in the printed circuit board of the present invention is preferably 100 μm or less, and more preferably in the range of 5-50 μm.

With regard to the aforementioned substrates, in addition to printed circuit boards with pre-formed circuits and flexible printed circuit boards, paper-phenol resin, paper-epoxy resin, glass cloth-epoxy resin, glass-poly Imide, glass cloth/non-woven fabric-epoxy resin, glass cloth/paper-epoxy resin, synthetic fiber-epoxy resin, fluororesin, polyethylene, polyphenylene ether, polyphenylene oxide, cyanic acid Copper foil laminates, polyimide films, PET films, glass substrates, ceramic substrates, wafer boards, etc. of all grades (FR-4, etc.) of composite materials such as esters.

The resin insulating layer of the printed circuit board of the present invention is suitable as a permanent film, and among them, it is preferably used as a solder resist layer and an interlayer insulating material.

The laminated structure of the present invention has a substrate, a plurality of resin insulating layers formed on the substrate, and at least one of the plurality of resin insulating layers is an insulating resin layer formed of the curable resin composition of the present invention That's it.

Regarding the basic structure of the laminated structure of the present invention, it is sufficient as long as it is ordinary. For example, there can be mentioned an insulating resin layer (L1) provided adjacent to the substrate (S), and a surface layer, that is, the outermost layer. Layers of things. Another layer may be further provided between the insulating resin layer (L1) and the surface layer. Even if no other layer is provided, for example, an alternate layer of the insulating resin layer (L1) and the resin insulating layer (L2) can be formed. For example, insulating resin layer (L1)/resin insulating layer (L2)/insulating resin layer (L1)/resin insulating layer (L2) may be formed. [Example]

Hereinafter, examples and comparative examples are shown to specifically explain the present invention, but the present invention is not limited by the following examples. Furthermore, the following "parts" and "%", unless otherwise stated, are all based on quality.

GPC measurement conditions Measuring machine: HLC8320GPC (manufactured by Tosoh Corporation) Detector: refractive index Solvent: Tetrahydrofuran (THF) Column composition: TSKguardcolumn HxL-L, TSKgel-G4000HxL, G3000HxL, G2000HxL, G1000HxL Temperature: 40℃ Flow rate: 1.0ml/min

FT-IR measurement conditions Measuring machine: FT/IR-4100 (Japan Seiko Co., Ltd.) Sample preparation conditions: The sample is obtained by coating the solution on the KBr plate and drying it with warm air as the measurement sample.

Example 1 In the flask equipped with thermometer, cooling tube, and stirrer, flush with nitrogen, and add 30 parts of maleimide compound (BMI-2300 manufactured by Daiwa Chemicals), 5.7 parts of sorbic acid, 35.7 parts of cyclohexanone, and Keep at 60°C for 5 hours. After confirming the disappearance of sorbic acid by GPC, it was taken out to obtain an acid-modified maleimide resin (A-1). The solid acid value of the obtained resin was 77 mgKOH/g, and the carboxyl equivalent was 729 g/eq.

Example 2 Flush with nitrogen in the flask equipped with thermometer, cooling tube and stirrer, and add 30 parts of maleimide compound (BMI-1000 manufactured by Daiwa Chemicals), 5.7 parts of sorbic acid, 35.7 parts of cyclohexanone, and Keep at 60°C for 5 hours. After confirming the disappearance of sorbic acid by GPC, it was taken out to obtain an acid-modified maleimide resin (A-1). The solid acid value of the obtained resin was 77 mgKOH/g, and the carboxyl equivalent was 729 g/eq.

Comparative example 1 In a 2L reaction vessel equipped with a thermometer, a stirrer, a reflux cooler and a nitrogen inlet, 294.8 parts of ethyl diethylene glycol acetate (hereinafter referred to as EDGAc) and 196.5 parts of N,N-dimethylacetate were added Amine (hereinafter DMAc), 400.0 parts of BMI-1000 (4,4'-diphenylmethane bismaleimide manufactured by Daiwa Chemical Industry Co., Ltd.), 243.3 parts of p-aminophenol, under nitrogen flow in the liquid, It took 150 minutes to heat up to 120°C. In this reaction vessel, 339.3 parts of RIKACID TH (manufactured by New Japan Rika Co., Ltd., 1,2,3,6-tetrahydrophthalic anhydride) was added, and the reaction was continued at 120°C. After 4.5 hours from heating to 150°C, after confirming that there is no change in the FT-IR spectrum of the resin, 709.7 parts of EDGAc was added, and the pressure was reduced at 140°C to distill off DMAc. After the distillation was completed, 196.5 parts of EDGAc was added and cooled to obtain an imine resin solution (A'-1) with a non-volatile content of 50%.

Comparative example 2 Add 563 parts by mass of diethylene glycol monoethyl ether acetate (EDGAc) and 400 parts by mass of 4,4'-diphenylmethane bismaleic acid to a reaction vessel equipped with a thermometer, a stirrer, and a nitrogen inlet. Imine (Daiwa Chemical Industry Co., Ltd., "BMI-1000"), 60.9 parts by mass of p-aminophenol, heated to 120°C in 150 minutes under nitrogen flow in the liquid, and reacted for 3 hours to obtain non-volatile matter 45% resin solution (A'-2).

Preparation of resin composition According to the composition ratio shown in Table 1, EDGAc was blended so that the final non-volatile content (N.V) became 50% by mass to prepare a curable resin composition.

Determination of the glass transition temperature (Tg) of the film The curable resin composition blended in the above ratio is coated on a glass substrate with a 6MIL applicator, placed in a hot air dryer, heated at 80°C for 30 minutes, heated at 120°C for 30 minutes, and heated at 200°C 2 hour. Then, the cured film was detached from the substrate and used as a test piece. According to the following conditions, the dynamic viscoelasticity of the sample for measurement was measured, and the temperature of the maximum value of Tanδ of the obtained spectrum was used as the glass transition temperature (Tg). The obtained results are shown in Table 1 as "Tg (°C) of the film". Measuring machine: Rheovibron RSA-II (manufactured by Rheometrics) Fixture: Stretch Between the chucks: 20mm Measuring temperature: 25℃～400℃ Measurement frequency: 1Hz Heating rate: 3℃/min

Alkali developability The curable resin composition is coated on a tinplate substrate so that the film thickness after drying becomes 25 to 35 μm. Then, the coated plate was dried in a dryer at 80°C for 30 minutes to prepare a test piece. After immersing it in a 1% potassium carbonate aqueous solution at 30°C and shaking for 3 minutes, it was washed with tap water, and the remaining condition of the coating film was visually observed to evaluate the alkali developability. The case where all the coating film is dissolved is regarded as "○", and the case where there is residual, even if only a part is still regarded as "×"

Furthermore, the terms in the table are as follows. N-680: DIC Co., Ltd., cresol novolac resin type epoxy resin, epoxy equivalent 212g/eq 2E4MZ: 2-ethyl-4-methylimidazole

[Table 1] Example Comparative example 1 2 1 2 Epoxy resin N-680 10 10 10 10 hardener (A-1) 34.5 (A-2) 34.5 (A'-1) 17.3 (A'-2) 16.2 catalyst 2E4MZ/phr 0.1 0.1 0.1 0.1 Tg of film(℃) 262 256 204 152 Alkali developability ○ ○ ○ X

no.

Fig. 1 is the FT-IR chart of the acid-modified maleimide resin obtained in Example 1 of the present invention. 2 is a GPC chart of the acid-modified maleimide resin obtained in Example 1 of the present invention.

no.

Claims (18)

A curable resin composition characterized by comprising an acid-modified maleimide resin (A) and a curable resin (B), wherein the acid-modified maleimide resin (A) contains the structure (1) The structure (1) is formed by adding a fatty acid with a conjugated diene or its derivative (a1) to the N-substituted maleimide group. The curable resin composition of claim 1, wherein the carboxyl equivalent of the acid-modified maleimide resin (A) is in the range of 200 to 10000 [g/eq]. The curable resin composition of claim 1 or 2, wherein the weight average molecular weight of the acid-modified maleimide resin (A) is in the range of 300 to 10,000. The curable resin composition according to any one of claims 1 to 3, wherein the acid-modified maleimide resin (A) has at least two of the structure (1) in one molecule. The curable resin composition according to any one of claims 1 to 4, wherein the structure in which the fatty acid having a conjugated diene or its derivative (a1) is added to an N-substituted maleimide group (1) is the structure represented by the following structural formula (i):

[In formula (i), R is a hydrogen atom or an aliphatic hydrocarbon group with 1 to 20 carbon atoms; X is a direct bond or a divalent aliphatic hydrocarbon group with 1 to 20 carbon atoms]. The curable resin composition according to any one of claims 1 to 5, wherein the acid-modified maleimide resin (A) is represented by the following structural formula (ii):

[In formula (ii), R ¹ is a divalent organic group having an aromatic ring or an aliphatic hydrocarbon, R is a hydrogen atom or an aliphatic hydrocarbon group with 1 to 20 carbon atoms, and X is a direct bond or a carbon number of 1 to 20 bis divalent aliphatic hydrocarbon group]. The curable resin composition according to any one of claims 1 to 5, wherein the acid-modified maleimide resin (A) is represented by the following structural formula (iii):

[In formula (iii), R is a hydrogen atom or an aliphatic hydrocarbon group with 1-20 carbon atoms, X is a direct bond or a divalent aliphatic hydrocarbon group with 1-20 carbon atoms, s is an integer of 0-10, t is an integer from 0 to 10 and s+t is 2 or more; however, the repeating structure can be random or block. When s is 1 or more, it can also be a structure without acid modification at the end ]. The curable resin composition according to any one of claims 1 to 7, wherein the curable resin (B) is an epoxy resin. The curable resin composition according to any one of claims 1 to 8, which further contains a photopolymerization initiator (C). The curable resin composition according to any one of claims 1 to 8, which further contains a diluent (D). A cured product obtained by curing the curable resin composition of any one of claims 1 to 10. A curable resin composition for forming a solder resist layer, comprising the curable resin composition according to any one of claims 1 to 10. A dry film having a curable resin layer containing the curable resin composition according to any one of claims 1 to 10. A printed circuit board has a resin insulating layer formed by thermally curing a curable resin layer containing the curable resin composition according to any one of claims 1 to 10. A laminated structure, which is a laminated structure having a base material and a plurality of resin insulating layers formed on the base material, characterized in that at least one of the plurality of resin insulating layers is composed of as claimed in claims 1 to 10 A layer formed of any one of the curable resin compositions. An acid-modified maleimide resin characterized by being represented by the following structural formula (ii) or (iii):

[In formula (ii), R ¹ is a divalent organic group having an aromatic ring or an aliphatic hydrocarbon, R is a hydrogen atom or an aliphatic hydrocarbon group with 1 to 20 carbon atoms, and X is a direct bond or a carbon number of 1 to 20 divalent aliphatic hydrocarbon group];

[In formula (iii), R is a hydrogen atom or an aliphatic hydrocarbon group with 1-20 carbon atoms, X is a direct bond or a divalent aliphatic hydrocarbon group with 1-20 carbon atoms, n is an integer of 0-10, m is an integer from 0 to 10, and n+m is 2 or more; however, the repeating structure can be random or block. When n is 1 or more, it can also be the end without acid modification structure]. The acid-modified maleimide resin of claim 16, which is an acid-modified maleimide resin represented by the structural formula (iii), in which a fatty acid having a conjugated diene or a derivative thereof ( The addition ratio of a1) is 0.02 to 1 mol relative to 1 mol of N-substituted maleimino group. A hardener comprising the acid-modified maleimide resin as claimed in claim 16 or 17.

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