JP2005105005A - Curable composition and cured product thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable composition having excellent preservation stability, rapidly advancing a curing reaction at a curing temperature and forming a cured film having various excellent characteristics such as electrical insulating properties without causing discoloring and curing shrinkage of a cured coated film and to provide a cured product having high insulation reliability formed by using the composition. <P>SOLUTION: The curable composition comprises (A) a carboxy group-containing resin, (B) a compound having an oxetanyl group and (C) an imidazole compound. As a preferred embodiment, the imidazole compound (C) is at least any of which the compound is soluble in at least one kind of liquid component in the composition and has ≥0.1 mass% amount dissolved therein based on the whole composition or has ≤200°C melting point. As a more preferred embodiment, the curable composition comprises (D) an s-triazine compound and/or dicyandiamide in addition to each of the components. The curable composition may be a liquid form or a form of a dry film. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a curable composition in a liquid form or a dry film form suitable for applications such as circuit board manufacture and mounting on electronic components, and a cured product thereof, and more particularly, a consumer or industrial printed wiring board solder. The present invention relates to a curable composition suitable for forming a resist, an insulating layer between conductor circuit layers, and the like, and a cured product thereof.

  Epoxy resins typified by bisphenol A type epoxy resins have excellent adhesion, heat resistance, chemical resistance, and electrical insulation, and thus have been widely used for adhesives, resists, casting agents, laminates, It is used for applications such as paints and sealants. However, with the development of the electrical industry and the semiconductor industry, for example, improvement in characteristics such as heat resistance, toughness, water resistance, and chemical resistance has been required, and various epoxy resins have been proposed to satisfy such characteristics. For example, polynuclear epoxy resins such as cresol novolac type epoxy resins and phenol novolac type epoxy resins have been proposed as epoxy resins having excellent heat resistance. However, although these epoxy resins are certainly excellent in heat resistance, they have a drawback that they are susceptible to cracking due to thermal shock because they have large shrinkage upon curing, little elongation, and lack toughness.

In addition, since the polyfunctional epoxy resin as described above has high reactivity, the curable resin composition containing the polyfunctional epoxy resin has poor storage stability and is easily gelled before coating, so that it can be composed in a one-pack type. It was difficult and there was a problem in terms of workability.
Furthermore, the curable resin composition containing the polyfunctional epoxy resin has a problem in storage stability at room temperature even in the form of a dry film, and the shelf life is shortened. There was a need to do.

In recent years, oxetane compounds have attracted attention as compounds that do not have such problems and can replace epoxy resins. From the viewpoint of creating new organic reactions and applying them to polymer synthesis, organic reactions using ring-opening addition reactions of oxetane rings, which are 4-membered ring ethers, have been studied. For example, oxetane compounds and active esters Studies have been made and reported on the synthesis of polyesters having a primary hydroxyl group in the side chain (see Non-Patent Document 2) by the addition reaction (see Non-Patent Document 1) and polyaddition reaction of bisoxetane and dicarboxylic acid. More recently, a polyaddition reaction between bisoxetanes and bisphenols (see Non-Patent Document 3) has been reported, and Patent Document 1 discloses a thermosetting composition containing an oxetane compound and a polycarboxylic acid. However, in any case, in specific examples, a quaternary onium salt having a halogen ion such as tetraphenylphosphonium bromide (TPPB) as an anion species is used as a catalyst for the curing reaction.
T. Nishikubo and K. Sato, Chem. Lett., 697 (1991) T. Nishikubo, A. Kameyama, A. Suzuki, Reactive & Functional Polymers, 37, 19 (1998) T. Nishikubo, A. Kameyama, M. Ito, T. Nakajima, H. Miyazaki, Journal of Polymer Chemistry, Vol. 37, pp. 2781-2790 (1999) JP-A-11-43540 (Claims)

  However, as in the past, a curable composition of an oxetane compound using a quaternary onium salt having a halogen ion such as tetraphenylphosphonium bromide (TPPB) as an anion species as a catalyst for the curing reaction is in terms of curing reactivity. It has not yet reached a satisfactory level, and the presence of halogen ions has a problem in terms of electrical characteristics, which has been an obstacle to practical application to printed wiring boards having conductor circuits. Furthermore, when such a curable composition was applied to a printed wiring board, there also existed a problem of producing coloring in a cured coating film.

  Therefore, the object of the present invention is that there is no problem due to the use of an epoxy resin as a thermosetting component as described above, and it has the advantages of an oxetane compound used in place of it as it is, and a conventional quaternary onium salt as a catalyst. There is no problem when used, it has excellent storage stability, the curing reaction proceeds promptly at the curing temperature, and there is no coloring or curing shrinkage of the cured coating film, and it has excellent characteristics such as electrical insulation. It is providing the curable composition which can form a cured film, and the hardened | cured material with high insulation reliability formed using it.

In order to achieve the object, according to the present invention, (A) a carboxyl group-containing resin, (B) a compound having an oxetanyl group (hereinafter referred to as “oxetane compound”), and (C) an imidazole compound are contained. A curable composition is provided.
In a preferred embodiment, the imidazole compound (C) is dissolved in at least one liquid component in the composition, and the amount of the imidazole compound (C) is 0.1% by mass or more based on the whole composition. Or the melting point is 200 ° C. or lower, or at least one of them. Here, melting | fusing point means the value measured based on the method as described in JISK0064.
In a more preferred embodiment, the curable composition contains (D) s-triazine compound and / or dicyandiamide in addition to the above components.
The curable composition may be in liquid form or in the form of a dry film.
Furthermore, according to this invention, the hardened | cured material obtained by hardening | curing the above curable compositions is provided.

  Since the curable composition of the present invention uses an imidazole compound as a catalyst for a curing reaction system containing an oxetane compound as a thermosetting component, it has excellent storage stability and a rapid curing reaction at a curing temperature. The cured product obtained proceeds and has excellent electrical characteristics. That is, the curable composition of the present invention is inferior in storage stability in the case of using an epoxy resin as a conventional thermosetting component, has no problem that the cured coating film undergoes curing shrinkage, and is used instead of the oxetane compound. While maintaining the advantages of the above, there is no problem of inferior electrical properties when using a conventional quaternary onium salt as a catalyst and coloring of the cured coating film, electrical insulation, heat resistance, plating resistance, hardness It can form cured products with excellent properties such as crack resistance (toughness) and adhesion, and can be used for various applications such as various resist materials, sealants, adhesives, paints, printing inks, especially solder resists for printed wiring boards. It is also useful as an interlayer insulation material for build-up multilayer printed wiring boards. Furthermore, it is advantageous in terms of workability because it can be formed into one liquid and a dry film having excellent storage stability at room temperature can be produced.

  As a result of intensive studies on a catalyst having high activity and not deteriorating electrical characteristics as a reaction catalyst for oxetanyl group and carboxyl group, the present inventors have found that imidazole as a curing catalyst for a curable composition containing a carboxyl group-containing resin and an oxetane compound. It has been found that when a compound is used, a cured product having excellent storage stability and excellent electrical properties can be obtained, and the present invention has been completed. The advantage of using an imidazole compound as the catalyst is that the curability at the curing temperature is good and the cured product is less colored. Therefore, not only the printed wiring board but also the cured coating film is used. It can be advantageously used in various applications such as liquid crystal parts where coloring is not desired.

Moreover, the curable composition containing an oxetane compound together with a carboxyl group-containing resin has no disadvantages when an epoxy resin is used as a thermosetting component as in the prior art, and can enjoy the advantages of using an oxetane compound.
That is, the oxetane compound added as a thermosetting component to the curable composition of the present invention has a four-membered ring oxetanyl group, which reacts with the carboxyl group of the carboxyl group-containing resin at the time of thermosetting and is mainly primary. As a result, it is possible to obtain a cured film with excellent adhesion to the substrate compared to the case of using a polyfunctional epoxy compound that mainly generates a secondary hydroxyl group, and the ethylene unit after the reaction due to the four-membered ring. Therefore, a cured film with less volume shrinkage, excellent toughness, and excellent crack resistance can be obtained. In addition, since the polyfunctional oxetane compound has a relatively low reactivity at a relatively low temperature compared to the polyfunctional epoxy compound, the curable composition containing the polyfunctional oxetane compound has excellent storage stability and can be composed in a one-pack type. In addition, a dry film that can be stored at room temperature for a long period of time can be produced, which is advantageous in terms of workability.
Furthermore, by adding an s-triazine compound and / or dicyandiamide to the curable composition of the present invention, the resistance to gold plating, discoloration resistance, and adhesion to a substrate are further improved.

Hereinafter, each component of the curable composition of this invention is demonstrated in detail.
First, as the carboxyl group-containing resin (A), any resin having a carboxyl group can be used, and is not limited to a specific one. Any of these may be suitably used.
(1) a carboxyl group-containing resin obtained by copolymerizing an unsaturated carboxylic acid (a) and a compound (b) having an unsaturated double bond,
(2) An organic compound having one carboxyl group in one molecule and no ethylenic unsaturated bond in the epoxy group of the copolymer of the compound (b) having an unsaturated double bond and glycidyl (meth) acrylate A carboxyl group-containing resin obtained by reacting the acid (c) and reacting the resulting secondary hydroxyl group with a saturated or unsaturated polybasic acid anhydride (d),
(3) a carboxyl group-containing resin obtained by reacting a hydroxyl group-containing polymer (e) with a saturated or unsaturated polybasic acid anhydride (d),
(4) a carboxyl group-containing resin obtained by reacting a reaction product of a bisepoxy compound (f) with a dicarboxylic acid (g) with a saturated or unsaturated polybasic acid anhydride (d), and (5) bis A carboxyl group-containing resin obtained by reacting a reaction product of an epoxy compound (f) and a bisphenol (h) with a saturated or unsaturated polybasic acid anhydride (d).

  The carboxyl group-containing resin (1) includes an unsaturated carboxylic acid (a) such as acrylic acid and methacrylic acid, and an unsaturated double bond such as styrene, α-methylstyrene, lower alkyl (meth) acrylate, and isobutylene. Is a copolymer of the compound (b) having an unsaturated carboxylic acid (a), which is one of the monomer components, and retains the carboxyl group as it is. It is soluble. In this specification, (meth) acrylate is a general term for acrylate and methacrylate, and the same applies to other similar expressions.

  The carboxyl group-containing resin (2) includes the compound (b) having an unsaturated double bond and having no hydroxyl group or acidic group, such as alkyl (meth) acrylate, substituted or unsubstituted styrene, and glycidyl (meta ) Organic acid (c) having one carboxyl group in one molecule and no ethylenically unsaturated bond in the glycidyl group of a copolymer having an acrylate main chain, for example, an alkylcarboxylic acid having 2 to 17 carbon atoms It is a resin obtained by reacting an acid, an aromatic group-containing alkylcarboxylic acid or the like, and adding the polybasic acid anhydride (d) to the generated secondary hydroxyl group. The introduction of a carboxyl group in this resin is produced by reacting an organic acid with the pendant glycidyl group of the above copolymer, and a polybasic acid anhydride is added to a secondary hydroxyl group located near the main chain. Therefore, the carboxyl group is bonded to a site near the main chain of the side chain, and contact with the basic inorganic fine particles is controlled by the steric hindrance between the main chain and the side chain. As a result, a composition containing such an alkali-soluble carboxyl group-containing resin together with an inorganic filler exhibits excellent storage stability, and hardly changes in viscosity or gels during storage.

  The carboxyl group-containing resin (3) is a hydroxyl group-containing polymer (e), such as an olefinic hydroxyl group-containing polymer, an acrylic polyol, a rubber polyol, a polyvinyl acetal, a styrene allyl alcohol resin, and celluloses. It is a resin in which a carboxyl group is introduced by reacting the relatively weak polybasic acid anhydride (d). Since such a carboxyl group-containing resin has a hydrophilic group (carboxyl group, hydroxyl group), it exhibits good wettability to the substrate, and the curable composition containing this has stable adhesion to the substrate in each step. Good storage stability.

  The carboxyl group-containing resins (4) and (5) are bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, brominated bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, biphenol. -Type epoxy resin, bis-epoxy compound such as bixylenol-type epoxy resin (f) and dicarboxylic acids (g) such as oxalic acid, malonic acid, succinic acid, phthalic acid, isophthalic acid, or bisphenols such as bisphenol A and bisphenol F By reacting the reaction product with (h) with a polybasic acid anhydride (d), a resin having excellent thermal stability is obtained.

In the curable composition of the present invention, in addition to the carboxyl group-containing resin as described above, a carboxyl group-containing photosensitive resin having an ethylenically unsaturated double bond can be used. Resin.
(1) A carboxyl group-containing photosensitive resin obtained by adding an ethylenically unsaturated group as a pendant to a copolymer of an unsaturated carboxylic acid (a) and a compound (b) having an unsaturated double bond,
(2) A secondary product produced by reacting an unsaturated carboxylic acid (a) with a copolymer of a compound (i) having an epoxy group and an unsaturated double bond and a compound (b) having an unsaturated double bond. A carboxyl group-containing photosensitive resin obtained by reacting a saturated or unsaturated polybasic acid anhydride (d) with a hydroxyl group of
(3) A compound of an acid anhydride (j) having an unsaturated double bond and a compound (b) having an unsaturated double bond is reacted with a compound (k) having a hydroxyl group and an unsaturated double bond. Carboxyl group-containing photosensitive resin obtained by
(4) Esterification reaction (total esterification or partial esterification) of the epoxy group of the polyfunctional epoxy compound (m) having at least two epoxy groups in one molecule and the carboxyl group of the unsaturated monocarboxylic acid (n) Carboxyl group-containing photosensitive resin obtained by reacting a saturated or unsaturated polybasic acid anhydride (d) with the generated hydroxyl group.
(5) Compound (i) having an epoxy group and an unsaturated double bond is further added to a carboxyl group-containing resin obtained by reacting a hydroxyl group-containing polymer (e) with a saturated or unsaturated polybasic acid anhydride (d). Carboxyl group-containing photosensitive resin obtained by reaction,
(6) A polyfunctional epoxy compound (m) having at least two epoxy groups in one molecule, an unsaturated monocarboxylic acid (n), at least two hydroxyl groups in one molecule, and an epoxy group. Carboxyl group-containing photosensitivity obtained by reacting a reaction product (I) with a compound (p) having one other reactive group other than a hydroxyl group with a saturated or unsaturated polybasic acid anhydride (d). resin,
(7) Unsaturated group-containing polycarboxylic acid urethane comprising the reaction product of the reaction product (I), a saturated or unsaturated polybasic acid anhydride (d), and an unsaturated group-containing monoisocyanate (q) resin,
(8) An unsaturated monocarboxylic acid (n) is reacted with a polyfunctional oxetane compound (r) having at least two oxetane rings in one molecule, and the primary hydroxyl group in the resulting modified oxetane resin is saturated or A carboxyl group-containing photosensitive resin obtained by reacting an unsaturated polybasic acid anhydride (d),
(9) Obtained by introducing an unsaturated double bond into the reaction product of the bisepoxy compound (f) and the dicarboxylic acid (g) and subsequently reacting with the saturated or unsaturated polybasic acid anhydride (d). Carboxyl group-containing photosensitive resin,
(10) Obtained by introducing an unsaturated double bond into the reaction product of the bisepoxy compound (f) and the bisphenol (h) and subsequently reacting with the saturated or unsaturated polybasic acid anhydride (d). A carboxyl group-containing photosensitive resin, and (11) a reaction product of a novolak-type phenol resin (s) and an alkylene oxide (t) with an unsaturated monocarboxylic acid (n), and the resulting reaction product is saturated. Or the carboxyl group-containing photosensitive resin obtained by making an unsaturated polybasic acid anhydride (d) react.

The carboxyl group-containing resins as described above may be used alone or in combination, but in any case, these are 10 to 80% by mass, preferably 20 to 60% by mass, based on the total amount of the composition. It is preferable to mix.
Moreover, as said carboxyl group-containing resin, an acid value of 30-250 mgKOH / g, Preferably 50-200 mgKOH / g can be used suitably. When the acid value of the resin is lower than 30 mgKOH / g, it is not preferable because a sufficient curing reaction with the oxetane compound (B) is difficult to proceed.

（式中、Ｒ¹は水素原子又は炭素数１〜６のアルキル基である。）
アルキル基としては、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、ｓｅｃ−ブチル基、ｔ−ブチル基、ｎ−ペンチル基、イソペンチル基、ネオペンチル基、ｎ−ヘキシル基、イソヘキシル基等の直鎖又は分岐鎖のアルキル基が挙げられる。これらの中でも、３−ヒドロキシメチルオキセタン、３−メチル−３−ヒドロキシメチルオキセタン、３−エチル−３−ヒドロキシメチルオキセタンが好ましい。 As the oxetane compound (B), either a monofunctional oxetane compound having one oxetanyl group in the molecule or a polyfunctional oxetane compound having two or more oxetanyl groups in the molecule can be used. Although not limited, it is preferable to use a polyfunctional oxetane compound.
As the monofunctional oxetane compound, an oxetane compound represented by the following general formula (1) can be preferably used.

(In the formula, R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, t-butyl group, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, Examples thereof include a linear or branched alkyl group such as an isohexyl group. Among these, 3-hydroxymethyl oxetane, 3-methyl-3-hydroxymethyl oxetane, and 3-ethyl-3-hydroxymethyl oxetane are preferable.

上記一般式（２）において、Ｒ¹は前記と同じ意味であり、Ｒ²は、炭素数１〜１２の線状又は分岐状飽和炭化水素類、炭素数１〜１２の線状又は分岐状不飽和炭化水素類、下記式（Ａ）、（Ｂ）、（Ｃ）、（Ｄ）及び（Ｅ）で示される芳香族炭化水素類、式（Ｆ）及び（Ｇ）で示されるカルボニル基を含む直鎖状又は環状のアルキレン類、式（Ｈ）及び（Ｉ）で示されるカルボニル基を含む芳香族炭化水素類から選択される２つの原子価を持った基である。その他の２官能オキセタン化合物としては、カルド型、ナフタレン型などが挙げられる。 Examples of the bifunctional oxetane compound include bisoxetanes represented by the following general formula (2).

In the general formula (2), R ¹ has the same meaning as described above, and R ² represents a linear or branched saturated hydrocarbon having 1 to 12 carbon atoms, linear or branched non-carbon having 1 to 12 carbon atoms. Saturated hydrocarbons, aromatic hydrocarbons represented by the following formulas (A), (B), (C), (D) and (E), including carbonyl groups represented by formulas (F) and (G) It is a group having two valences selected from linear or cyclic alkylenes and aromatic hydrocarbons containing a carbonyl group represented by formulas (H) and (I). Examples of other bifunctional oxetane compounds include cardo type and naphthalene type.

式中、Ｒ³は、水素原子、炭素数１〜１２のアルキル基、アリール基、又はアラルキル基を表わし、Ｒ⁴は、−Ｏ−、−Ｓ−、−ＣＨ₂−、−ＮＨ−、−ＳＯ₂−、−ＣＨ（ＣＨ₃）−、−Ｃ（ＣＨ₃）₂−、又は−Ｃ（ＣＦ₃）₂−を表わし、Ｒ⁵は、水素原子又は炭素数１〜６のアルキル基を表わす。

In the formula, R ³ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group, or an aralkyl group, and R ⁴ represents —O—, —S—, —CH ₂ —, —NH—, — SO ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ) ₂ —, or —C (CF ₃ ) ₂ — is represented, and R ⁵ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. .

式中、ｎは１〜１２の整数を表わす。

In the formula, n represents an integer of 1 to 12.

  Examples of the trifunctional oxetane compound include, in addition to the compound represented by the following general formula (3), hydroxyl groups such as oxetane and novolac resin, poly (hydroxystyrene), calixarene, or silicone resin such as silsesquioxane. An etherified product with a resin having In addition, a copolymer of an unsaturated monomer having an oxetane ring and an alkyl (meth) acrylate is also included.

上記一般式（３）において、Ｒ¹は前記と同じ意味であり、Ｒ⁶は、前記エーテル化物の水酸基含有樹脂残基、下記式（Ｊ）、（Ｋ）及び（Ｌ）で示されるような炭素数１〜１２の分岐状アルキレン基、式（Ｍ）、（Ｎ）及び（Ｐ）で示される芳香族炭化水素類である。また、ｍは残基Ｒ⁶に結合している官能基の数を表わし、３以上の整数、好ましくは３〜５０００の整数である。

In the general formula (3), R ¹ has the same meaning as described above, and R ⁶ represents a hydroxyl group-containing resin residue of the etherified product, as represented by the following formulas (J), (K), and (L). A branched alkylene group having 1 to 12 carbon atoms and aromatic hydrocarbons represented by formulas (M), (N) and (P). M represents the number of functional groups bonded to the residue R ⁶ and is an integer of 3 or more, preferably an integer of 3 to 5000.

式中、Ｒ⁷は、水素原子、炭素数１〜６のアルキル基、又はアリール基を表わす。

In the formula, R ⁷ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group.

  The oxetane compound (B) as described above can be used alone or in combination of two or more, but in particular, a finely divided oxetane compound that is sparingly soluble in an organic solvent described later, or a soluble oxetane compound and a sparingly soluble oxetane compound. It is preferable to use a combination of oxetane compounds. The blending amount of the oxetane compound (B) as the thermosetting component is appropriately 5 to 200 parts by mass, preferably 15 to 100 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin (A). It is.

The present invention is characterized in that the imidazole compound (C) is used as a catalyst for the curing reaction of the carboxyl group-containing resin and the oxetane compound.
The imidazole compound may be liquid or solid, and may be liquefied to the extent that it sufficiently contributes to the reaction between the carboxyl group and the oxetanyl group at the curing temperature. That is, when the imidazole compound is present in a liquid state at the time of curing, the probability that the imidazole compound exists between the carboxyl group of the carboxyl group-containing resin and the oxetanyl group of the oxetane compound increases, and the curing reaction proceeds rapidly. However, when a solid imidazole compound is added, the viscosity of the composition is lowered, and the coating workability is excellent. Therefore, in this respect, it is preferable to use a solid imidazole compound. In the case of a solid, for example, there are a method of dissolving in at least one liquid component such as a solvent and a monomer, and a method of liquefying an imidazole compound by heating during curing. In order to liquefy the imidazole compound by heating at the time of curing, it is preferable to use a imidazole compound having a melting point of 200 ° C. or lower, more preferably a curing temperature or lower (generally 180 ° C. or lower). Alternatively, it is desirable to use an imidazole compound that dissolves in at least one liquid component in the composition and has a dissolution amount of 0.1% by mass or more based on the entire composition. However, the curing temperature is limited and set according to the heat resistance of the substrate and the intended use of the composition. Therefore, in the present invention, depending on the curing temperature, the imidazole compound having the above-described properties may be used alone or in appropriate combination of two or more so that the imidazole compound can be liquefied to such an extent that it sufficiently contributes to the reaction. it can.

  Specific examples of the imidazole compound (C) include imidazole (melting point 89 to 90 ° C), 2-methylimidazole (melting point 137 to 145 ° C), 1-methylimidazole (liquid, boiling point 198 ° C), 2-ethylimidazole (melting point). 85-86 ° C), 2-ethyl-4-methylimidazole (liquid or solid, boiling point 164 ° C (2.666 kPa)), 2-phenylimidazole (melting point 137-147 ° C), 2-undecylimidazole (melting point 69- 74 ° C.), 2-heptadecylimidazole (melting point: 86-91 ° C.), 1-benzyl-2-methylimidazole (liquid), 2-phenyl-4-methylimidazole (melting point: 174-184 ° C.), 1-cyanoethyl-2 -Methylimidazole (melting point 53-56 ° C.), 1-cyanoethyl-2-phenylimidazole (melting point 05-111 ° C.), 1- (2-cyanoethyl) -2-ethyl-4-methylimidazole (liquid), 1-aminoethyl-2-methylimidazole (liquid), 1- (cyanoethylaminoethyl) -2-methyl Imidazole (liquid), N- [2- (2-methyl-1-imidazolyl) ethyl] urea (melting point 172 to 174 ° C.), 1-cyanoethyl-2-undecylimidazole (melting point 47 to 52 ° C.), 1-cyanoethyl 2-methylimidazolium trimellitate (melting point 170-177 ° C.), 1-cyanoethyl-2-phenylimidazolium trimellitate (melting point 175-183 ° C.), 1-cyanoethyl-2-ethyl-4-methylimidazolium Trimellitate (melting point 157-166 ° C.), 1-cyanoethyl-2-undecylimidazolium trimelli (Melting point 123-129 ° C), 2,4-diamino-6- [2'-undecylimidazolyl- (1 ')]-ethyl-s-triazine (melting point 187-195 ° C), 1-dodecyl-2 -Ethyl-3-benzylimidazolium chloride (melting point about 60 ° C), N, N'-bis (2-methyl-1-imidazolylethyl) urea (melting point 182 to 185 ° C), N, N '-(2-methyl -1-imidazolylethyl) -adipamide (melting point: 184-186 ° C.), 2-phenyl-4-methyl-5-hydroxymethylimidazole (melting point: 191-195 ° C.), 2-methylimidazole isocyanuric acid adduct (melting point: about 135 ° C.), 2-phenylimidazole isocyanuric acid adduct (melting point: about 140 ° C.), 1-benzyl-2-phenylimidazole (liquid or solid, melting point: about 0 ° C.), 4-formyl imidazole (mp one hundred seventy-four to one hundred and seventy-five ° C.), and 1-vinylimidazole (liquid) and the like.

  The amount of the imidazole compound (C) used is in the range of 0.1 to 25 mol%, preferably 0.5 to 20 mol%, more preferably 1 to 15 mol%, relative to 1 mol of the oxetanyl group. It is. When the amount of the imidazole compound (C) used is less than 0.1 mol% with respect to the oxetanyl group, the reaction does not proceed easily at a practical rate. Since the promotion effect is not seen, it is not preferable in terms of economy.

In a preferred embodiment of the curable composition of the present invention, as described above, the component (D) contains an s-triazine compound and / or dicyandiamide. Examples of the s-triazine compound include melamine, guanamine, acetoguanamine, benzoguanamine, 2,4,6-triamino-S-triazine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2, Examples include 4-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine / isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxyethyl-S-triazine / isocyanuric acid adduct, and the like. Preferably, an s-triazine compound and / or dicyandiamide that also functions as an adhesion-imparting agent is used in combination with the imidazole compound (C) as the curing catalyst.
The compounding amount of the s-triazine compound and / or dicyandiamide is sufficient in a normal quantitative ratio, for example, 0.1 to 20 parts by mass, preferably 0. 0 to 100 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin (A). It is a ratio of 5 to 15.0 parts by mass.

  The above-mentioned carboxyl group-containing resin (A), oxetane compound (B) and imidazole compound (C), and, if necessary, an s-triazine compound and / or dicyandiamide (D), an organic solvent, a filler, a curing accelerator and the like are blended. In addition, the curable composition of the present invention can easily obtain a cured product by a method similar to a conventionally known method, and can be used as a resist material for a printed wiring board, a resin insulating material, a sealant, an adhesive, and a paint. Can be used as etc. Further, the curable composition of the present invention is sufficiently mixed and melted as necessary using an extruder, kneader, roll, etc., if necessary, and then molded using a casting or transfer molding machine, and heated. By doing so, a cured product can be obtained. Furthermore, the prepreg obtained by dissolving the curable composition of the present invention in an organic solvent, impregnating a base material such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, paper, etc., and drying by heating is used. A cured product can also be obtained by press molding. When the carboxyl group-containing resin (A) is a carboxyl group-containing photosensitive resin, it can be cured by irradiation with active energy rays by adding a photopolymerization initiator in addition to the above components.

  Furthermore, the curable composition of this invention can contain an organic solvent as needed. Examples of organic solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol Glycol ethers such as monomethyl ether, dipropylene glycol diethyl ether, triethylene glycol monotyl ether; ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, Propylene glycol monobutyl ether acetate, dipropylene glycol Acetic esters such as nomethyl ether acetate; Alcohols such as ethanol, propanol, ethylene glycol, and propylene glycol; Aliphatic hydrocarbons such as octane and decane; Petroleum such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha Examples thereof include a solvent, and can be used alone or in combination of two or more.

  The purpose of use of the organic solvent is to dissolve and dilute the other components, thereby adjusting the viscosity suitable for the coating method, or alternatively, to form a film by coating on a support film and then temporarily drying, This is because a dry film can be created. The amount of the organic solvent used is not limited to a specific ratio, but a range of about 30 to 300 parts by mass is appropriate for 100 parts by mass of the carboxyl group-containing resin (A), and a coating method to be selected. It can be set appropriately according to.

Furthermore, an epoxy compound can also be mixed with the curable composition of the present invention as a part of the thermosetting component as long as the effect of using the oxetane compound (B) as the thermosetting component is not impaired. As the epoxy compound, any compound having two or more epoxy groups in the molecule can be used. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, brominated bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, biphenol type epoxy resin, bixylenol type epoxy resin, alicyclic epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, brominated phenol novolak type epoxy resin, Glycidyl ether compounds such as bisphenol A novolac epoxy resin, glycidyl ether such as diglycidyl terephthalate, diglycidyl hexahydrophthalate, diglycidyl dimer Tellurium compounds, triglycidyl isocyanurate, N, N, N ′, N′-tetraglycidylmetaxylenediamine, N, N, N ′, N′-tetraglycidylbisaminomethylcyclohexane, N, N-diglycidylaniline, etc. Known and commonly used epoxy compounds such as glycidylamine compounds can be mentioned. These epoxy compounds can be used alone or in combination of two or more. As the epoxy compound, any epoxy compound that is hardly soluble or soluble in an organic solvent can be used.
Furthermore, in order to accelerate the thermosetting reaction, a small amount of known epoxy curing accelerators such as quaternary ammonium salts, quaternary phosphonium salts and tertiary amines can be used in combination.

  In addition, the curable composition of the present invention includes barium sulfate, barium titanate, silicon oxide powder, amorphous silica, talc, magnesium carbonate, carbonic acid as necessary for the purpose of improving properties such as adhesion and hardness. Known and commonly used inorganic fillers such as calcium, aluminum oxide, aluminum hydroxide, glass fiber, carbon fiber and mica powder can be blended, and the blending ratio is suitably in the range of 0 to 60% by weight of the composition, preferably It is 5-40 mass%. Further, as required, known and commonly used colorants such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, naphthalene black, hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol , Known and conventional thermal polymerization inhibitors such as pyrogallol and phenothiazine, known and commonly used thickeners such as asbestos and fine silica, defoamers and / or leveling agents such as silicones, fluorines and polymers, thiazoles, Known and commonly used additives such as adhesion-imparting agents such as triazole and silane coupling agents can be blended.

  In the production of the dry film of the present invention, the curable composition of the present invention as described above is adjusted to a viscosity suitable for the coating method as necessary, and an appropriate support film such as polyethylene is used in the same manner as the conventional method. On a flexible base film having a thickness of about 15 to 125 μm, such as terephthalate (PET), polyethylene (PE), polypropylene (PP), polycarbonate, polyethersulfone, polyvinyl chloride, etc. After coating so as to have a film thickness of about 150 μm, it is dried and, for example, by evaporating and drying the organic solvent contained in the composition at a temperature of about 60 to 140 ° C., generally about 120 ° C., the dried film layer is formed. It is set as the dry film which has. The dry film layer formed on the support film is a release film having a film thickness of about 15 to 100 μm, such as a PET film, a PP film, a PE film, or a film coated or baked with silicone on this when not used. It is preferable to store a protective film having properties. The protective film is for stably protecting the dry film when not in use, and is removed during use. When the carboxyl group-containing resin has an unsaturated double bond, the film thickness 1 of a water-soluble composition such as polyvinyl alcohol or partially saponified polyvinyl acetate is further formed on the dry film layer in order to prevent oxygen desensitization. A layer of about 10 μm can be formed.

  When using a dry film having a protective film, the protective film is peeled off, the dry film layer is brought into close contact with the substrate, the support film is peeled off, and a dry film layer made of a curable composition is formed. Transcript. As the transfer method, a thermocompression bonding method in which the substrate to be treated is heated in advance is preferable. Alternatively, a vacuum pressure bonding method in which pressure bonding is performed under vacuum may be used. The substrate to be treated can be arbitrarily selected according to the purpose of using the dry film, but for example, when used as an interlayer insulating layer of a build-up multilayer printed wiring board, it is transferred to an inner layer board.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the following examples are only for illustrating the present invention and do not limit the present invention. In the following description, “part” means “part by mass” unless otherwise specified.

The raw materials used in the following Examples 1 to 11 and Comparative Examples 1 to 3 are shown in Table 1.

Examples 1-11 and Comparative Examples 1-3:
Each component was mix | blended with the compounding ratio shown in Table 2, and it knead | mixed using the roll mill, and prepared the thermosetting composition.

Curing catalyst solubility:
To 0.1 g of the imidazole compound used as a curing catalyst in Examples 1 to 11 above, 9.9 g of propylene glycol monomethyl ether acetate used as a solvent was added, heated in an oven at 60 ° C. for about 1 hour, and cooled to room temperature. Thereafter, the state of the solution was visually observed. The results are shown in Table 3.
○: Completely soluble Δ: Slightly precipitated imidazole compound in the solution X: Slightly precipitated imidazole compound in the solution

Coating film production:
The thermosetting compositions of Examples 1 to 11 and Comparative Examples 1 to 3 were each applied to a copper-clad laminate with a thickness of 50 μm with an applicator and heated at 170 ° C. for 60 minutes to obtain a cured coating film. Got.

Performance evaluation:
(1) Curability:
The surface of the cured coating film was rubbed ten times with absorbent cotton soaked with acetone, and the presence or absence of cloudiness on the surface was visually observed and evaluated according to the following criteria.
○: No change at all.
Δ: Cloudy on the surface.
X: The coating film dissolved and reached the ground.

(2) Discoloration:
The surface of the cured coating film was visually observed and evaluated according to the following criteria.
A: Almost no discoloration.
○: Color changed to pale yellow.
Δ: Yellowish color.
X: The color changed to brown.

(3) Heat resistance:
The cured coating film was immersed in a solder bath at 260 ° C. for 10 seconds in accordance with the method of JIS C-6481, and then subjected to a peeling test using a cellophane adhesive tape. Judgment criteria are as follows.
○: No change in coating film.
Δ: Some change is observed in the coating film.
X: The film peeled off.

(4) Pencil hardness:
It measured based on JIS K-5400.

(5) Gold plating resistance:
Using a commercially available electroless nickel plating bath and electroless gold plating bath, plating was performed under conditions of nickel 3 μm and gold 0.03 μm, and the surface state of the cured coating film was observed. Judgment criteria are as follows.
A: No change at all.
○: There is almost no change.
(Triangle | delta): The thing from which peeling or cloudiness produced.
X: Remarkably peeled off or clouded.

(6) Migration resistance:
For the compositions of Examples 1 to 7, 10, 11 and Comparative Example 1, a comb electrode having a line / space of 100/100 μm was used, and the composition was 130 ° C., 85% R.D. H. In the constant temperature and humidity chamber, DC25V was applied, and the presence or absence of migration after 50 hours was examined. Judgment criteria are as follows.
○: No migration.
Δ: Some migration.
X: A thing with remarkable migration.

(7) Storage stability:
The compositions of Examples 1 to 11 and Comparative Examples 1 to 3 were put into a 50 ° C. oven and evaluated by the rate of change in viscosity after 5 days. Judgment criteria are as follows.
○: Change rate of viscosity is 30% or less.
Δ: Viscosity change rate of 30% or more.
X: Gelled.

表４に示される結果から明らかなように、本発明の各実施例によれば、組成物中の少なくとも１種の液状成分に対して溶解し、かつその溶解量が組成物全体に対して０．１質量％以上であるイミダゾール化合物及び／又は融点が２００℃以下のイミダゾール化合物を硬化触媒として添加した硬化性組成物であるため、保存安定性に優れると共に、電気絶縁性等の特性に優れた硬化塗膜が得られた。また、５０℃での保存安定性に優れることから、常温保存可能なドライフィルムに有用であることが明らかとなった。これに対し、硬化触媒としてテトラフェニルホスホニウムブロミドを添加した比較例１の場合、電気絶縁性が悪いと共に、硬化塗膜に変色が生じた。一方、硬化促進剤としてのメラミンを添加した比較例２の場合、硬化性が悪いと共に、耐熱性、金めっき耐性等の特性においても劣っていた。また、熱硬化性成分としてエポキシ樹脂を用いた比較例３の場合、塗膜特性の点では問題はないが、保存安定性に劣っていた。
また、実施例１０及び１１の結果から明らかなように、本発明の硬化性組成物にｓ−トリアジン化合物であるメラミン又はジシアンジアミドを添加することにより、金めっき耐性や耐変色性がより一層向上した。なお、実施例８、９の組成物については、１７０℃×６０分の加熱条件では表２に示されるように硬化性、耐熱性等の特性が充分ではないが、２００℃にて６０分間加熱したところ、充分な特性を有する硬化物が得られた。
The results of each test are summarized in Table 4.

As is apparent from the results shown in Table 4, according to each example of the present invention, the composition dissolves in at least one liquid component in the composition, and the amount of dissolution is 0 with respect to the entire composition. .1% by mass or more of an imidazole compound and / or an imidazole compound having a melting point of 200 ° C. or less added as a curing catalyst, it has excellent storage stability and excellent properties such as electrical insulation. A cured coating was obtained. Moreover, since it was excellent in the storage stability at 50 degreeC, it became clear that it was useful for the dry film which can be stored at normal temperature. On the other hand, in the case of Comparative Example 1 in which tetraphenylphosphonium bromide was added as a curing catalyst, the electrical insulation was poor and the cured coating film was discolored. On the other hand, in the case of Comparative Example 2 in which melamine as a curing accelerator was added, the curability was poor and the properties such as heat resistance and gold plating resistance were inferior. Moreover, in the case of the comparative example 3 which used the epoxy resin as a thermosetting component, there was no problem in the point of the coating-film characteristic, but it was inferior in storage stability.
Further, as is clear from the results of Examples 10 and 11, the addition of melamine or dicyandiamide, which is an s-triazine compound, to the curable composition of the present invention further improved gold plating resistance and discoloration resistance. . In addition, about the composition of Examples 8 and 9, although characteristics, such as sclerosis | hardenability and heat resistance, are not enough as shown in Table 2 on the heating conditions of 170 degreeC x 60 minutes, it heats for 60 minutes at 200 degreeC. As a result, a cured product having sufficient characteristics was obtained.

Claims (5)

A curable composition comprising (A) a carboxyl group-containing resin, (B) a compound having an oxetanyl group, and (C) an imidazole compound. The imidazole compound (C) is dissolved in at least one liquid component in the composition, and the amount of the imidazole compound (C) is 0.1% by mass or more with respect to the entire composition, or the melting point is 200 ° C. The curable composition according to claim 1, which is at least one of the following. Furthermore, (D) s-triazine compound and / or dicyandiamide are contained, The curable composition of Claim 1 or 2 characterized by the above-mentioned. The curable composition according to claim 1, wherein the curable composition is in the form of a dry film. Hardened | cured material obtained by hardening | curing the curable composition as described in any one of the said Claims 1 thru | or 4.