JP2021102702A - Curable resin composition, cured product thereof, and semiconductor sealing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable resin composition having excellent curability, a high glass transition point of a cured product, excellent moisture resistance reliability, and a cured product having dielectric properties, a cured product thereof, and a semiconductor seal. Providing stop material. A curable resin composition containing an epoxy resin (A), an active ester (B), and a quaternary phosphonium salt carboxylate (C) as essential components, and a cured product thereof. In particular, as the carboxylate (C) of the quaternary phosphonium salt, the following general formulas (1) [in the formula (1), R1 to R4 are independently linear or branched with 1 to 16 carbon atoms. Alkyl group, or a phenyl group which may have a substituent on the aromatic ring. ], It is preferable that the phosphonium cation contains a salt of an aliphatic polycarboxylic acid, an alicyclic polycarboxylic acid, or an anionic residue of an aromatic polycarboxylic acid. [Selection diagram] None

Description

The present invention is excellent in curability and moisture resistance reliability of the obtained cured product, and can be suitably used for circuit boards such as printed wiring boards and semiconductor package substrates, semiconductor encapsulants, paints, casting applications, and the like. The present invention relates to a resin composition and a cured product thereof.

Thermosetting compositions containing epoxy resin as the main ingredient are used in adhesives, molding materials, paints, photoresist materials, color-developing materials, etc., and also have excellent heat resistance and moisture resistance of the obtained cured products. Due to its characteristics, it is widely used in the electrical and electronic fields such as semiconductor encapsulants and insulating materials for printed wiring boards.

In the electrical and electronic fields, due to the tendency of high-speed signals in various electronic devices and improvement of transmission characteristics due to high-frequency communication, insulating materials with low dielectric constant and dielectric loss tangent are used as insulating materials for semiconductor encapsulants and printed wiring boards. Is desired. In addition, in the semiconductor encapsulating material, reduction of the amount of chlorine during moisture resistance is an indispensable property in order to protect the semiconductor element.

So far, a technique of using di (α-naphthyl) isophthalate as a curing agent for an epoxy resin has been known as a resin material having a low dielectric constant and dielectric loss tangent in a cured product (see, for example, Patent Document 1). The epoxy resin composition described in Patent Document 1 is based on the case where a conventional epoxy resin curing agent such as phenol novolac resin is used by using di (α-naphthyl) isophthalate as the epoxy resin curing agent. In comparison, the dielectric constant and dielectric tangent value of the cured product are certainly low, but the curability is low, and a highly basic curing accelerator such as pyridines and imidazoles is required, and a large amount of chlorine is extracted during wet heat treatment. Therefore, moisture resistance and reliability have been an issue.

Further, as a curing agent for an epoxy resin, a technique of using an active ester resin and a phenol compound in combination has been proposed (see, for example, Patent Document 2). In Patent Document 2, when a phenol compound is used in combination, sufficient curability is exhibited even with a phosphorus-based curing accelerator known for its low chlorine extraction property, but a secondary hydroxyl group is generated in the cured product, so that the active ester resin is used. The dielectric constant and dielectric loss tangent were higher than when only the curing agent was used as the curing agent.

Further, in the bonding method between a semiconductor device using a flip chip connection method, which has been widely adopted in recent years, and a circuit board such as a package board, the circuit board itself is exposed to a high thermal environment during solder reflow, so that the circuit board material If the curing itself is not sufficient, there is a problem that the glass transition temperature of the insulating material rises during solder reflow, causing curing shrinkage. When the above-mentioned active ester compound is used, the reactivity between the active ester compound and the epoxy resin is low and the circuit board is insufficiently cured. Therefore, the glass transition temperature becomes high when the cured product such as solder reflow is reheated. This curing shrinkage is caused, and a large stress is generated in the solder ball which is the joint portion between the circuit board and the semiconductor, which causes a poor connection of the wiring.

On the other hand, as a means for increasing the reactivity between the active ester and the epoxy resin, an increase in the amount of the curing catalyst can be mentioned, but in this case, the curing time becomes extremely short, so that the required molding time cannot be secured and molding defects occur. It was the one that caused it. Further, in many printed circuit board manufacturing processes, there is a step of impregnating a glass cloth with an epoxy resin composition dissolved in a solvent and drying it to form a prepreg. However, if the curing time is extremely short, the epoxy is epoxy during the drying time. Curing of the resin composition partially progresses, or if the drying time is shortened to prevent this, the amount of solvent remaining in the prepreg increases, which eventually causes molding defects and curing defects. There was a limit to the amount increase.

As described above, the present situation is that a composition having a low dielectric constant and a low dielectric loss tangent and having excellent curability and moisture resistance reliability and a cured product thereof have not been obtained.

International Publication No. 2018/008411 International Publication No. 2018/008416

Therefore, the problem to be solved by the present invention is a curable resin composition capable of providing a cured product having excellent curability, a high glass transition point of the cured product, excellent moisture resistance reliability, and having dielectric properties. It is an object of the present invention to provide a product, a cured product thereof, and a semiconductor encapsulating material.

As a result of diligent studies to solve the above problems, the present inventors have added a specific compound to a resin composition using an active ester as a curing agent for an epoxy resin to obtain sufficient curability and moisture resistance of the cured product. We have found that reliability can be obtained, and have completed the present invention.

That is, the present invention is a curable resin composition containing an epoxy resin (A), an active ester compound (B), and a carboxylate (C) of a quaternary phosphonium salt as essential components, and a cured product thereof. , And a semiconductor encapsulating material using the same.

According to the present invention, a curable resin composition having a high glass transition point of a cured product, providing a cured product having excellent dielectric properties and moisture resistance reliability, and having sufficient curability at the time of curing. A cured product and a semiconductor encapsulating material having these performances can be provided.

Hereinafter, the present invention will be described in detail.
The epoxy resin (A) used in the curable resin composition of the present invention is not particularly limited, and for example, a bisphenol type epoxy resin such as a bisphenol A type epoxy resin or a bisphenol F type epoxy resin; a biphenyl type epoxy resin, Biphenyl type epoxy resin such as tetramethylbiphenyl type epoxy resin; phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, epoxy product of condensate of phenols and aromatic aldehyde having phenolic hydroxyl group , Novolak type epoxy resin such as biphenyl novolac type epoxy resin; triphenylmethane type epoxy resin; tetraphenylethane type epoxy resin; dicyclopentadiene-phenol addition reaction type epoxy resin; phenol aralkyl type epoxy resin; naphthol novolac type epoxy resin, Naftor-phenol co-condensed novolak type epoxy resin, naphthol-cresol co-condensed novolak type epoxy resin, diglycidyloxynaphthalene, structural formula below

で表される４官能ナフタレン型エポキシ樹脂等の分子構造中にナフタレン骨格を有するエポキシ樹脂；リン原子含有エポキシ樹脂等が挙げられる。また、これらのエポキシ樹脂は単独で用いてもよく、２種以上を混合してもよい。

An epoxy resin having a naphthalene skeleton in the molecular structure of a tetrafunctional naphthalene type epoxy resin represented by (2); a phosphorus atom-containing epoxy resin and the like can be mentioned. Further, these epoxy resins may be used alone or in combination of two or more.

Here, the phosphorus atom-containing epoxy resin includes epoxies of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (hereinafter abbreviated as "HCA"), HCA and quinones. Epoxy products of phenol resin obtained by reacting with HCA, epoxy resin obtained by modifying phenol novolac type epoxy resin with HCA, epoxy resin obtained by modifying cresol novolac type epoxy resin with HCA, and bisphenol A type epoxy resin with HCA and quinone. Epoxy resin obtained by modifying with a phenol resin obtained by reacting with other species, and epoxy resin obtained by modifying bisphenyl A type epoxy resin with a phenol resin obtained by reacting HCA with quinones, etc. Can be mentioned.

Further, in order to raise the glass transition temperature of the cured product of the curable resin composition to improve the heat resistance, the epoxy group equivalent of the epoxy resin (A) is 1,000 g / equivalent or less, particularly 700 g / equivalent or less, particularly 500 g. / It is preferably equal to or less than the equivalent amount.

Among these epoxy resins (A), dicyclopentadiene-phenol addition reaction type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, phenol aralkyl type epoxy resin, biphenyl novolac type epoxy resin and xantene type epoxy resin are particularly. A dicyclopentadiene-phenol addition reaction type epoxy resin is particularly preferable from the viewpoint of excellent flame retardancy and dielectric properties, and particularly preferably from the viewpoint of excellent dielectric properties of the cured product.

The active ester (B) used in the present invention is a compound or resin that is reactive with an epoxy group and has two or more carbonyloxy bonds in one molecule, and specifically, polyvalent carboxylic acids and phenols. Ester compound (b1) reacted with, polyhydric phenol polyaryl ester or polyalkyl ester (b2), bisphenol polyaryl ester or polyalkyl ester (b3), biphenol polyaryl ester or polyalkyl ester (b4) ), Polyaryl ester or polyalkyl ester of phenol resin (b5), aromatic polyester (b6) obtained by reacting polyvalent aromatic phenol with polyvalent carboxylic acid with monofunctional phenol or monofunctional carboxylic acid. Can be mentioned. Here, as the alkyl group or aryl group constituting the alkyl ester or aryl ester in the above (b2) to (b5), specifically, methyl, ethyl, n-propyl, i-propyl, t-butyl and the like can be used. Alkyl groups with 1 to 4 carbon atoms, or 1 to 1 carbon atoms such as phenyl group, biphenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, i-propylphenyl group, t-butylphenyl group, etc. Examples thereof include a phenyl group nuclearly substituted with an alkyl group of 4. Among these, an aryl group is particularly preferable from the viewpoint of heat resistance.

The polyvalent carboxylic acid used in the ester compound (b1) obtained by reacting the polyvalent carboxylic acid with phenols is an aliphatic carboxylic acid such as adipic acid, an aromatic carboxylic acid such as phthalic acid anhydride, or terephthalic acid. And examples of the phenols include phenol, cresol, α-naphthol, and β-naphthol. The polyaryl ester or polyalkyl ester (b2) of the polyhydric phenol described above is an alkyl esterifying agent or aryl esterification of a polyhydric phenol such as resorcinol, hydroquinone, 1,6-dihydroxynaphthalene, and 2,7-dihydroshiquinaphthalene. Examples thereof include ester compounds obtained by reacting with an agent.

The above-mentioned polyaryl ester or polyalkyl ester of bisphenol (b3) is a compound obtained by reacting bisphenols such as bisphenol A, bisphenol F, and bisphenol S with an alkyl esterifying agent or an aryl esterifying agent to esterify a phenolic hydroxyl group. In the above-mentioned polyaryl ester or polyalkyl ester of biphenol (b4), biphenols such as biphenol and tetramethylbiphenol were reacted with an alkyl esterifying agent or an aryl esterifying agent to esterify a phenolic hydroxyl group. Examples include compounds.

The polyaryl ester or polyalkyl ester (b5) of the phenol resin described above is a phenol novolac resin, a cresol novolak resin, a naphthol novolak resin, and the following general formula (1).

（式中、Ｒ^１は水素原子又は炭素原子数１〜４のアルキル基、Ｒ^２は水素原子又はメチル基を表し、Ｒ^３及びＲ^４は、水素原子、炭素原子数１〜４のアルキル基、又はフェニル基を表し、ｎは繰り返し単位の平均で０〜１０である。）
であらわされるアラルキル型フェノール樹脂、下記一般式（２）

(In the formula, R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ² represents a hydrogen atom or a methyl group, and R ³ and R ⁴ are hydrogen atoms or an alkyl group having 1 to 4 carbon atoms. , Or a phenyl group, where n is an average of 0 to 10 in repeating units.)
Aralkyl type phenol resin represented by the following general formula (2)

（式中、Ｒ^５は、水素原子、炭素原子数１〜４のアルキル基、又はフェニル基を表し、ｎは繰り返し単位の平均で０〜１０である。）
で表されるフェノール樹脂をアルキルエステル化剤又はアリールエステル化剤とを反応させてフェノール性水酸基をエステル化した樹脂が挙げられる。

(In the formula, R ⁵ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group, and n is an average of 0 to 10 in repeating units.)
Examples thereof include a resin obtained by reacting a phenol resin represented by (1) with an alkyl esterifying agent or an aryl esterifying agent to esterify a phenolic hydroxyl group.

Here, examples of the alkyl esterifying agent used in the production of (b1) to (b5) include saturated fatty acids such as formic acid, acetic acid, propionic acid and butanoic acid, and acid fluorides, acidified compounds and acids thereof. Examples thereof include acid halides such as bromides and acid iodides, and acid anhydrides which are bimolecular dehydration condensates of these saturated fatty acids. Examples of the aryl esterifying agent include benzoic acid, phenylbenzoic acid and methylbenzoic acid. , Ethyl benzoic acid, n-propyl benzoic acid, alkyl benzoic acids such as i-propyl benzoic acid and t-butyl benzoic acid, and acid halides such as acid fluorides, acidified compounds, acid bromides and acid iodide. , And acid anhydride which is a bimolecular dehydration condensate of these alkyl benzoic acids.

The aromatic polyester (b6) obtained by reacting the above-mentioned polyhydric aromatic phenol with the polyvalent carboxylic acid with a monofunctional phenol or a monofunctional carboxylic acid includes the above-mentioned polyhydric phenol, bisphenol or biphenol. , Polyallylate (b6-1) obtained by reacting aromatic dicarboxylic acid or its halide, phenolic resin having a molecular structure in which phenols are knotted via an aliphatic cyclic hydrocarbon group, aromatic dicarboxylic acid or Examples thereof include the halide and polyarylate (b-2) having a structure obtained by reacting an aromatic monohydroxy compound.

Among these, polyaryl ester or polyalkyl ester (b5) of phenol resin, polyaromatic phenol, polyvalent carboxylic acid and monofunctional phenol from the viewpoint of excellent reactivity with epoxy resin (A). Alternatively, an aromatic polyester (b6) obtained by reacting with a monofunctional carboxylic acid is preferable. Further, among the above (b5), polyaryl esters or polyalkyl esters of novolak resins such as phenol novolac resin, cresol novolak resin, and naphthol novolak resin are particularly preferable because the improvement effect according to the present invention is remarkable.

Here, the polyaryl ester or polyalkyl ester of the novolak resin is one in which a part or all of the phenolic hydroxyl groups of the novolak resin is esterified, and in particular, 60 to 95 of the phenolic hydroxyl groups of the novolak type phenol resin. It is preferable that the modified phenol resin has a molecular structure in which% is alkyl-esterified or aryl-esterified, and the softening point thereof is in the range of 80 to 160 ° C. Here, the softening point of the phenol resin is a value measured by the ring-and-ball method (heating rate: 5 ° C./min) based on "JIS K7234-86".

Further, among the (b6), a phenol resin (i) having a molecular structure in which phenols are knotted via an aliphatic cyclic hydrocarbon group, an aromatic dicarboxylic acid or its halide (ii), and an aromatic. A polyaromatic (b6-2) having a structure obtained by reacting a monohydroxy compound (iii) is preferable because it has excellent heat resistance.

More specifically, the polyallylate (b6-2) is a phenol in the phenol resin (i) with respect to 1 mol of the carboxyl group or the acid halide group in the aromatic dicarboxylic acid or its halide (ii). It is particularly cured that it has a structure obtained by reacting the aromatic monohydroxy compound (iii) in a proportion of 0.05 to 0.75 mol and the aromatic monohydroxy compound (iii) in an amount of 0.25 to 0.95 mol. This is preferable because the dielectric adjacency of the object is low.

Here, in the phenol resin (i), the molecular structure in which phenols are knotted via an aliphatic cyclic hydrocarbon group is an unsaturated aliphatic cyclic hydrocarbon compound containing two double bonds in one molecule. Examples thereof include a structure obtained by a double addition reaction with phenols. Here, examples of the phenols include phenols and substituted phenols in which one or more alkyl groups, alkenyl groups, allyl groups, aryl groups, aralkyl groups, halogen groups and the like are substituted. Specific examples include cresol, xylenol, ethylphenol, isopropylphenol, butylphenol, octylphenol, nonylphenol, vinylphenol, isopropenylphenol, allylphenol, phenylphenol, benzylphenol, chlorphenol, bromphenol, naphthol, dihydroxynaphthalene and the like. Be done. Moreover, you may use a mixture of these. Among these, phenol is particularly preferable because it has excellent fluidity and curability.

Specific examples of the unsaturated alicyclic hydrocarbon compound include cyclopentadiene, dicyclopentadiene, tricyclopentadiene, tetrahydroindene, 4-vinylcyclohexene, 5-vinylnorbona-2-ene, α-pinene, and the like. Examples include β-pinene and limonene. Among these, dicyclopentadiene is preferable from the viewpoint of characteristic balance, particularly heat resistance and hygroscopicity. Since dicyclopentadiene is contained in petroleum fractions, industrial dicyclopentadiene may contain other aliphatic or aromatic diene as impurities, but it has heat resistance and curability. Considering moldability and the like, it is desirable that the product has a purity of 90% by mass or more of dicyclopentadiene.

Next, the aromatic dicarboxylic acid or its halide (ii) is an aromatic dicarboxylic acid such as isophthalic acid, terephthalic acid, 1,4-, 2,3-, or 2,6-naphthalenedicarboxylic acid, and these. Examples thereof include acid halides such as acid fluorides, acid salts, acid bromides and acid iodides. Among these, an acid chloride of an aromatic dicarboxylic acid is preferable from the viewpoint of particularly good reactivity, and dichloride of isophthalic acid and dichloride of terephthalic acid are preferable, and dichloride of isophthalic acid is particularly preferable.

Next, examples of the aromatic monohydroxy compound (iii) include phenols; alkylphenols such as o-cresol, m-cresol, p-cresol, and 3,5-xylenol; o-phenylphenol, p-phenylphenol, and the like. Aromatic phenols such as 2-benzylphenol, 4-benzylphenol and 4- (α-cumyl) phenol; naphthols such as α-naphthol and β-naphthol can be mentioned. Among these, α-naphthol and β-naphthol are particularly preferable from the viewpoint of lowering the dielectric loss tangent of the cured product.

The above-mentioned active ester compound (b6-2) has a structure obtained by reacting a phenol resin (i), an aromatic dicarboxylic acid or a halide (ii) thereof, and an aromatic monohydroxy compound (iii). However, in particular, the following structural formula (3)

（式中、Ｘはベンゼン環又はナフタレン環であり、ｋは０又は１を表し、ｎは繰り返し単位の平均値で０．０５〜４．０である。）
で表される構造のものがとりわけ硬化物の誘電正接が低くなる点から好ましい。

(In the formula, X is a benzene ring or a naphthalene ring, k represents 0 or 1, and n is an average value of repeating units of 0.05 to 4.0.)
The structure represented by is particularly preferable because the dielectric loss tangent of the cured product is low.

In particular, the value of n in the structural formula (3), that is, the average value of the repeating units in the range of 0.25 to 3.0 is preferable because the solution viscosity is low and the production is easy. Further, in the structural formula (3), it is preferable that the value of k is 0 from the viewpoint that the effect of the present invention becomes remarkable.

Here, n in the structural formula (1) can be obtained as follows.
[How to find n in structural formula (1)]
The styrene-equivalent molecular weights (α1, α2, α3, α4) corresponding to each of n = 1, n = 2, n = 3, and n = 4 and n = 1, n = by GPC measurement performed under the following conditions. The ratios (β1 / α1, β2 / α2, β3 / α3, β4 / α4) to the theoretical molecular weights (β1, β2, β3, β4) of 2, n = 3, and n = 4 were obtained, and these (β1 / Obtain the average value of α1 to β4 / α4). The value obtained by multiplying the number average molecular weight (Mn) obtained by GPC by this average value is defined as the average molecular weight. Next, the value of n is calculated by using the molecular weight of the structural formula a as the average molecular weight.

(GPC measurement conditions)
Measuring device: "HLC-8220 GPC" manufactured by Tosoh Corporation,
Column: Guard column "HXL-L" manufactured by Tosoh Corporation
+ "TSK-GEL G2000HXL" manufactured by Tosoh Corporation
+ "TSK-GEL G2000HXL" manufactured by Tosoh Corporation
+ "TSK-GEL G3000HXL" manufactured by Tosoh Corporation
+ "TSK-GEL G4000HXL" manufactured by Tosoh Corporation
Detector: RI (Differential Refractometer)
Data processing: "GPC-8020 Model II Version 4.10" manufactured by Tosoh Corporation
Measurement conditions: Column temperature 40 ° C
Developing solvent tetrahydrofuran
Flow velocity 1.0 ml / min Standard: The following monodisperse polystyrene with a known molecular weight was used in accordance with the measurement manual of "GPC-8020 Model II Version 4.10".
(Polystyrene used)
"A-500" manufactured by Tosoh Corporation
"A-1000" manufactured by Tosoh Corporation
"A-2500" manufactured by Tosoh Corporation
"A-5000" manufactured by Tosoh Corporation
"F-1" manufactured by Tosoh Corporation
"F-2" manufactured by Tosoh Corporation
"F-4" manufactured by Tosoh Corporation
"F-10" manufactured by Tosoh Corporation
"F-20" manufactured by Tosoh Corporation
"F-40" manufactured by Tosoh Corporation
"F-80" manufactured by Tosoh Corporation
"F-128" manufactured by Tosoh Corporation
Sample: A solution obtained by filtering 1.0 mass% of a tetrahydrofuran solution in terms of resin solid content with a microfilter (50 μl).

The method of reacting a phenol resin (ii-1), an aromatic dicarboxylic acid or a halide thereof (ii-2), and an aromatic monohydroxy compound (ii-3) specifically makes each of these components alkaline. It can be reacted in the presence of a catalyst.

Examples of the alkaline catalyst that can be used here include sodium hydroxide, potassium hydroxide, triethylamine, pyridine and the like. Among these, sodium hydroxide and potassium hydroxide are particularly preferable because they can be used in an aqueous solution state and the productivity is improved. In addition to these alkaline catalysts, a phase transfer catalyst such as a quaternary ammonium salt or a quaternary phosphonium salt may be used in combination with the reaction, if necessary.

When the active ester (B) thus obtained is used as a semiconductor encapsulating material, a varnish for a laminated board, or an adhesive film for build-up, it is mixed with other compounding components as it is, and further, an organic solvent is appropriately used. The desired curable resin composition can be produced by adjusting the amount.

As for the blending amount of the active ester (B), the curability is good when the molar ratio of the epoxy group of the epoxy resin (A) to the ester group of the active ester (B) is in the range of 0.8 to 1.1. It becomes a thing and is preferable.

The quaternary phosphonium salt carboxylate (C) used in the present invention has a function as a curing catalyst for the above-mentioned epoxy resin (A) and active ester (B), and can be blended into the resin composition. The curability can be improved.

Further, the carboxylate (C) of the quaternary phosphonium salt has a phosphorus-based accelerator (phosphonium salt) whose mother nucleus has a low chlorine extraction ability, and further has a carboxylate anion which is an ester-based anion. It is possible to achieve both curability and moisture resistance reliability (low chlorine extraction property) of the cured product.

In particular, the carboxylic acid salt is preferably a carboxylic acid salt having a polybasic acid structure of 2 or more because these effects are even more robust.

Examples of the carboxylate (C) of the quaternary phosphonium salt include the following general formula (1).

〔式（１）中、Ｒ^１〜Ｒ^４は、それぞれ独立に、炭素原子数１〜１６の直鎖状若しくは分岐鎖状のアルキル基、または芳香環状に置換基を有していてもよいフェニル基である。〕
で表されるホスホニウムカチオンと、
脂肪族ポリカルボン酸（ｃ−１）、脂環式ポリカルボン酸（ｃ−２）、または芳香族ポリカルボン酸（ｃ−３）のアニオン残基との塩を含むものである。

[In the formula (1), R ^{1 to} R ⁴ each independently have a linear or branched alkyl group having 1 to 16 carbon atoms, or a phenyl which may have an aromatic cyclic substituent. It is a group. ]
The phosphonium cation represented by
It contains a salt with an anion residue of an aliphatic polycarboxylic acid (c-1), an alicyclic polycarboxylic acid (c-2), or an aromatic polycarboxylic acid (c-3).

Examples of the aliphatic polycarboxylic acid (c-1) include the following general formula (2-1).

〔式（２−１）中、Ｒ^５〜Ｒ^８は、それぞれ独立に、水素原子、炭素原子数１〜４の直鎖状若しくは分岐鎖状のアルキル基、水酸基、アミノ基、カルボキシル基又はカルボキシアルキル基である〕
で表される脂肪族ポリカルボン酸であることが好ましい。

[In formula (2-1), R ^{5 to} R ⁸ are independently hydrogen atoms, linear or branched alkyl groups having 1 to 4 carbon atoms, hydroxyl groups, amino groups, carboxyl groups or carboxy groups. Alkyl group]
It is preferably an aliphatic polycarboxylic acid represented by.

The anion residue of the polycarboxylic acid is monovalent or divalent or more (typically) with the hydrogen atom of one or two or more (typically one) carboxyl groups of the polycarboxylic acid removed. Is a monovalent) carboxyl anion.

A salt of the above phosphonium cation and an anion residue of at least one aliphatic polycarboxylic acid is known, or can be easily obtained by a known method, for example, the method described in JP-A-63-190893. Can be manufactured.

For example, a solution of tetra-substituted phosphonium halide (solvent is water, methanol, etc.) is converted into a solution of tetra-substituted phosphonium hydroxide (solvent is water, methanol, etc.) by ion exchange, and the tetra-substituted solution thereof is used in the solution. A salt by neutralizing 1 mol of phosphonium hydroxide with 0.5 to 5 mol, more preferably 0.5 to 2 mol of the aliphatic polycarboxylic acid represented by the above general formula (2-1). Examples include the method of forming.

From the reaction mixture containing the obtained salt, the solvent is removed by an appropriate method, for example, vacuum distillation or the like to separate the desired salt. As the tetra-substituted phosphonium hydroxide, a commercially available product may be used.

Further, the aliphatic polycarboxylic acid represented by the general formula (2-1) may contain hydrated water, water of crystallization, adsorbed water and the like, and may be used alone or in combination of two or more. Can be used.

Further, instead of the aliphatic polycarboxylic acid, the corresponding aliphatic polycarboxylic acid anhydride may be used respectively.

The salt obtained by the above method is usually mainly composed of a 1: 1 salt of 1 mol of a phosphonium cation and 1 mol of an anion residue of at least one aliphatic polycarboxylic acid.

（式中Ｒ^１〜Ｒ^８は前記と同じである）
で表されるものである。

(Wherein ^R 1 to R ⁸ are as defined above)
It is represented by.

R ¹ to R ⁴ in the phosphonium cation in the above formula is a methyl group as a linear or branched alkyl group having 1 to 4 carbon atoms, an ethyl group, n- propyl group, i- propyl, n- butyl A group, a sec-butyl group, an iso-butyl group, and a tert-butyl group are preferable, or the phenyl group which may be substituted with an alkyl group is preferably a phenyl group or a p-tolyl group. In particular ^{, it is more preferable that all of R 1 to} R ⁴ are the above-mentioned linear or branched butyl groups.

Further, the anion portion in the above formula represents an anion residue (monovalent anion residue) of the aliphatic polycarboxylic acid represented by the general formula (2-1), and strictly speaking, a plurality of carboxyl groups or Among the carboxyl anions, the carboxyl group existing across the ethylene chain and the carboxyl anion are anion residues coordinated with the phosphonium cation.

It is considered that the coordination of the anion residue with the phosphonium cation causes a time lag until the onset of activity in the initial stage of heating, which causes low viscosity (potential) in the initial stage of heating. In this case, the ethylene chain is optimal from the viewpoint of the balance between the potential and the coordination force.

Therefore, as suitable aliphatic polycarboxylic acids described in the general formula (2-1), succinic acid in which all ^{R 5 to} R ^{8 are hydrogen atoms, R 5 to} R ⁷ are hydrogen atoms, and R ⁸ is a hydroxyl group. become malic ^acid, R 5, ^{R 6} is a hydrogen atom, ^{R 7} is hydroxyl, ^R 6 citrate and ^R 5 ^{R 8} are represented by carboxymethyl group, ^{R 7} is a hydrogen atom, ^{R 8} is a carboxyl group Butane-1,2,3,4-tetracarboxylic acid and the like are preferable. In addition, these aliphatic polycarboxylic acids can be used alone or in combination of two or more.

The alicyclic polycarboxylic acid (c-2) has the following general formulas (2-2) and (2-3).

〔式（２−２）、（２−３）中、Ｒ^１０は、メチレン基又はエチレン基を示し、Ｒ^１１〜Ｒ^１８は、それぞれ独立に、水素原子、炭素原子数１〜４の直鎖状若しくは分岐鎖状のアルキル基、又はカルボキシ基である。〕
で表される脂環式ポリカルボン酸である

[In formulas (2-2) and (2-3), R ¹⁰ represents a methylene group or an ethylene group, and R ^{11 to} R ¹⁸ are independent straight chains having a hydrogen atom and 1 to 4 carbon atoms, respectively. It is an alkyl group in the form of a branched or branched chain, or a carboxy group. ]
It is an alicyclic polycarboxylic acid represented by

Such a carboxylate of a quaternary phosphonium salt can also be obtained by the same method as described above. Instead of the alicyclic polycarboxylic acid represented by the general formula (2-2) and the alicyclic polycarboxylic acid represented by the general formula (2-3), the corresponding alicyclic polycarboxylic acid anhydrides, respectively. You may use things.

In the reaction product obtained by the same method as described above, in addition to the 1: 1 salt, other types of salts (phosphonium cation represented by the general formula (1) and at least one alicyclic polycarboxylic acid) Although some salts (salts with anionic residues of the acid) may be mixed, such reaction products can be used as they are.

The alicyclic polycarboxylic acid represented by the general formula (2-2), which is industrially easily available, is usually a mixture containing two or more kinds of acids represented by the general formula (2-2). There are many. Therefore, a salt of a mixed anion residue derived from a mixture containing two or more alicyclic polycarboxylic acids represented by the general formula (2-2) and a phosphonium cation represented by the general formula (1) is used. In this case as well, an excellent effect is exhibited.

Further, regarding the phosphonium salt containing the salt of the phosphonium cation represented by the general formula (1) and the anion residue of the alicyclic polycarboxylic acid represented by the general formula (2-3), the general formula (2-). Since the alicyclic polycarboxylic acid represented by 3) is practically a single product and is often obtained industrially, usually, the alicyclic polycarboxylic acid represented by one general formula (2-3) is used. It is advantageous from the viewpoint of industrial availability to use the salt obtained by using. Therefore, when the alicyclic polycarboxylic acid represented by the general formula (2-3) is used as a raw material, it is typically a 1: 1 salt.

Regarding the alicyclic polycarboxylic acids of the general formula (2-2) and the general formula (2-3), the following can be exemplified as preferable ones.

In the general formula ^(2-2), a ^{R 10} is methylene ^group, R 11 ^{to R 14} are all alicyclic polycarboxylic acid which is a hydrogen ^{atom, R 10} is a methylene ^group, the R 11 ^{to R 14} It is preferable that an alicyclic polycarboxylic acid in which any one of them is a methyl group and the remaining three are hydrogen atoms, or a mixture thereof.

In the general formula (2-3), any one of R ^{15 to} R ¹⁸ is an alicyclic polycarboxylic acid in which all hydrogen atoms are hydrogen atoms, or one of R ^{15 to} R ¹⁸ is a methyl group and the remaining three are hydrogen atoms. Alicyclic polycarboxylic acids, in which two of ^{R 15 to} R ^{18 (particularly R 16} and R ¹⁷ ) are carboxyl groups and the remaining two are hydrogen atoms, are preferred.

In particular, in the general formula (2-3), ^{either R 15 to} R ¹⁸ are all anionic residues of the alicyclic polycarboxylic acid which are hydrogen atoms, or two of RR ^{15 to} R ¹⁸ (particularly). , R ¹⁶ and R ¹⁷ ) are carboxyl groups and the remaining two are hydrogen atoms, more preferably alicyclic polycarboxylic acids.

In the alicyclic polycarboxylic acids represented by the general formulas (2-2) and (2-3), isomers in which two carboxyl groups bonded to adjacent carbon atoms are cis-arranged and isomers thereof. There are isomers in which the two carboxyl groups are trans-arranged. The cis configuration refers to the case where the two carboxyl groups are present on the same side with respect to the single bond between the two carbon atoms to which the two carboxyl groups are bonded. Further, the transformer arrangement refers to the case where one of the two carboxyl groups is present on a side different from the other with respect to the single bond between the two carbon atoms to which the two carboxyl groups are bonded.

In the present invention, the anion residue may be derived from alicyclic polycarboxylic acid in a cis configuration or derived from alicyclic polycarboxylic acid in a trans configuration, or is a mixture of both. May be good. When the alicyclic polycarboxylic acid used as a raw material is a trans-cis mixture and two carboxyl groups bonded to adjacent carbon atoms are a set, an anion derived from the alicyclic polycarboxylic acid in the cis configuration. It is preferable that the residue is 80% or more (area standard by GC (gas chromatography) analysis). Basically, the configuration of the raw material alicyclic polycarboxylic acid is also preserved in the phosphonium salt formation reaction, and the cis form content of the raw material alicyclic polycarboxylic acid produces phosphonium and alicyclic polycarboxylic acid. It is considered that the cis form content of the salt with the acid anion residue is almost the same.

The aromatic polycarboxylic acid (c-3) is not particularly limited, but for example, the following general formula (2-4)

〔式（２−４）中、Ｒ^１９〜Ｒ^２２は、それぞれ独立に、水素原子、アルキル基、水酸基、アミノ基又はアルコキシ基である。〕
で表される芳香族ポリカルボン酸であることが好ましい。

[In formula (2-4), R ^{19 to} R ²² are independently hydrogen atoms, alkyl groups, hydroxyl groups, amino groups or alkoxy groups. ]
It is preferably an aromatic polycarboxylic acid represented by.

Examples of the compound represented by the general formula (2-4) include phthalic acid, 4-methylphthalic acid, 4-hydroxyphthalic acid, 4-aminophthalic acid, 4-methoxyphthalic acid and the like.

Salts of phosphonium cations and anionic residues of phthalates are known or can be easily prepared by known methods.

For example, a method of forming a salt by reacting a solution of a tetra-substituted phosphonium halide with an alkali metal salt of phthalic acids in a solvent (solvent is water, methanol, etc.) can be mentioned. In this case, the tetra-substituted phosphonium halide and the alkali metal salts of phthalates may be used alone or in combination of two or more to form the above salt. When two or more kinds are mixed, two or more kinds of tetra-substituted phosphonium halides and alkali metal salts of phthalates may be mixed first, and then phosphonium phthalates may be formed, or two or more kinds of phosphonium phthalates may be formed. The acid salts may be mixed. The salt obtained by the above method usually contains a 1: 1 salt of 1 mol of a phosphonium cation and 1 mol of an anion residue of phthalates as a main component, and is represented by a general formula.

In the above formula, the anion portion represents an anion residue (monovalent anion residue) of phthalates represented by the general formula (2-4), and at this time, the carboxyl group and the carboxyl anion are actually equivalent. Is.

When the compound of the above formula is difficult to homogenize in the composition, it is used as a masterbatch obtained by mixing or reacting the compound with the active ester (B) in advance for the purpose of facilitating homogenization. You may.

Examples of the compound represented by the above formula include tetraphenylphosphonium phthalate, tetraphenylphosphonium 4-methylphthalate, tetraphenylphosphonium 4-hydroxyphthalate, tetraphenylphosphonium 4-aminophthalate, and tetraphenylphosphonium 4-. Methoxyphthalate, (4-methylphenyl) triphenylphosphonium phthalate, (4-methylphenyl) triphenylphosphonium 4-methylphthalate, (4-methylphenyl) triphenylphosphonium 4-hydroxyphthalate, ( Examples thereof include 4-methylphenyl) triphenylphosphonium 4-aminophthalate, (4-methylphenyl) triphenylphosphonium 4-methoxyphthalate and the like.

Here, the blending ratio of the carboxylic acid salt (C) of the quaternary phosphonium salt is 0.5 to 10 parts by mass per 100 parts by mass of the total mass of the epoxy resin (A) and the active ester (B). This is preferable from the viewpoint that the effect of the present invention is remarkably exhibited. Above all, when it is in the range of 0.5 to 4.0 parts by mass, the balance between curability and moisture resistance reliability is more excellent.

In the curable resin composition of the present invention, in addition to the active ester (B) as a curing agent for epoxy resins, amine compounds, amide compounds, acid anhydride compounds, and pheno compounds are used as long as the effects of the present invention are not impaired. Other epoxy resin curing agents (B') such as compound compounds may be used in combination. In this case, the curing agent (B') can be used by replacing a part of the active ester (B) with the curing agent (B'). That is, when the curing agent (B') is used in combination, the total of the active hydrogen in the curing agent (B') and the ester bond in the active ester (B) is the epoxy group 1 in the epoxy resin (A). The ratio is preferably 0.7 to 1.2 with respect to the molar. Further, the curing agent (B') can be used at a ratio of 50% by mass or less with respect to the total mass of the active ester (B).

May be used herein, amine compounds, diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenyl sulfone, isophoronediamine, imidazo - Le, BF 3 _- amine complex, guanidine derivatives and the like. Examples of the amide compound include a polyamide resin synthesized from a dimer of dicyandiamide and linolenic acid and ethylenediamine.

Acid anhydride compounds include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride. Examples include phthalic acid.

Phenol-based compounds include phenol novolac resin, cresol novolac resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin, dicyclopentadienephenol-added resin, phenol aralkyl resin, α-naphthol aralkyl resin, β-naphthol aralkyl resin, biphenyl aralkyl resin. , Trimethylol methane resin, tetraphenylol ethane resin, naphthol novolac resin, naphthol-phenol co-shrink novolac resin, naphthol-cresol co-shrink novolak resin, aminotriazine-modified phenol resin and the like. Specific examples of the aminotriazine-modified phenolic resin include copolymers of amino group-containing triazine compounds such as melamine and benzoguanamine, phenols such as phenol and cresol, and formaldehyde.

Among these, a polyhydric phenol-based compound is particularly preferable because it has a lower linear expansion coefficient of the cured product, is resistant to thermal and physical impacts, and has excellent toughness, and is preferably a phenol novolac resin, a cresol novolac resin, or a phenol aralkyl resin. , Α-Naftor aralkyl resin, β-naphthol aralkyl resin, biphenyl aralkyl resin, aminotriazine-modified phenol resin are preferable.

In the curable resin composition of the present invention, a curing accelerator may be used in combination with each of the above-mentioned components.

Examples of the curing accelerator that can be used here include imidazoles, tertiary amines, and tertiary phosphines.

Here, as the imidazoles, specifically, 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 2,4-dimethylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2 -Phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1- Vinyl-2-methylimidazole, 1-propyl-2-methylimidazole, 2-isopropylimidazole, 1-cyanomethyl-2-methyl-imidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2- In addition to undecylimidazole, 1-cyanoethyl-2-phenylimidazole and the like, masked imidazoles can be mentioned.

Specific examples of tertiary amines include trimethylamine, triethylamine, tripropylamine, tributylamine, tetramethylbutanediamine, tetramethylpentanediamine, tetramethylhexadiamine, triethylenediamine, N, N-dimethylbenzylamine, N, N-dimethylaniline, N, N-dimethyltoluidine, N, N-dimethylaniline, pyridine, picolin, quinoline, N, N'-dimethylaminopyridine, N-methylpiperidine, N, N'-dimethylpiperazine, 1, 8-diazabicyclo- [5,4,0] -7-undecene (DBU) and the like can be mentioned.

Specific examples of tertiary phosphines include trimethylphosphine, triethylphosphine, tripropylphosphine, tributylphosphine, triphenylphosphine, dimethylphenylphosphine, and methyldiphenylphosphine.

In the resin composition of the present invention, the blending amount of the epoxy resin (A) and the active ester (B) contains the active ester (B) with respect to a total of 1 equivalent of the epoxy groups from the viewpoint of excellent curability. It is preferable that the total number of active groups in the curing agent is 0.8 to 1.2 equivalents.

In addition, other thermosetting resins may be used in combination with the curable resin composition.

Examples of other thermosetting resins include cyanate ester resins, resins having a benzoxazine structure, maleimide compounds, vinylbenzyl compounds, acrylic compounds, and copolymers of styrene and maleic acid anhydride. When the other thermosetting resin described above is used in combination, the amount used is not particularly limited as long as the effect of the present invention is not impaired, but it should be in the range of 1 to 50 parts by mass out of 100 parts by mass of the resin composition. Is preferable.

Examples of the cyanate ester resin include bisphenol A type cyanate ester resin, bisphenol F type cyanate ester resin, bisphenol E type cyanate ester resin, bisphenol S type cyanate ester resin, bisphenol sulfide type cyanate ester resin, and phenylene ether type cyanate ester resin. , Naftyrene ether type cyanate ester resin, biphenyl type cyanate ester resin, tetramethylbiphenyl type cyanate ester resin, polyhydroxynaphthalene type cyanate ester resin, phenol novolac type cyanate ester resin, cresol novolac type cyanate ester resin, triphenylmethane type cyanate. Ester resin, tetraphenylethane type cyanate ester resin, dicyclopentadiene-phenol addition reaction type cyanate ester resin, phenol aralkyl type cyanate ester resin, naphthol novolac type cyanate ester resin, naphthol aralkyl type cyanate ester resin, naphthol-phenol co-condensed novolak Examples thereof include type cyanate ester resin, naphthol-cresol co-condensed novolak type cyanate ester resin, aromatic hydrocarbon formaldehyde resin modified phenol resin type cyanate ester resin, biphenyl modified novolak type cyanate ester resin, and anthracene type cyanate ester resin. Each of these may be used alone, or two or more types may be used in combination.

Among these cyanate ester resins, bisphenol A type cyanate ester resin, bisphenol F type cyanate ester resin, bisphenol E type cyanate ester resin, and polyhydroxynaphthalene type cyanate ester resin are particularly excellent in heat resistance. , Naftylene ether type cyanate ester resin and novolak type cyanate ester resin are preferably used, and dicyclopentadiene-phenol addition reaction type cyanate ester resin is preferable in that a cured product having excellent dielectric properties can be obtained.

The resin having a benzoxazine structure is not particularly limited, but for example, a reaction product of bisphenol F, formalin and aniline (FA type benzoxazine resin) or a reaction product of diaminodiphenylmethane, formalin and phenol (P-). d-type benzoxazine resin), reaction product of bisphenol A, formalin and aniline, reaction product of dihydroxydiphenyl ether, formalin and aniline, reaction product of diaminodiphenyl ether, formalin and phenol, dicyclopentadiene-phenol-added resin and formalin And aniline reaction products, phenolphthalein, formalin and aniline reaction products, diphenylsulfide, formalin and aniline reaction products, and the like. Each of these may be used alone, or two or more types may be used in combination.

Examples of the maleimide compound include various compounds represented by any of the following structural formulas (i) to (iii).

（式中Ｒはｍ価の有機基であり、α及びβはそれぞれ水素原子、ハロゲン原子、アルキル基、アリール基の何れかであり、ｓは１以上の整数である。）

(In the formula, R is an m-valent organic group, α and β are any of a hydrogen atom, a halogen atom, an alkyl group, and an aryl group, respectively, and s is an integer of 1 or more.)

（式中Ｒは水素原子、アルキル基、アリール基、アラルキル基、ハロゲン原子、水酸基、アルコキシ基の何れかであり、ｓは１〜３の整数、ｔは繰り返し単位の平均で０〜１０である。）

(In the formula, R is any of a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, a halogen atom, a hydroxyl group, and an alkoxy group, s is an integer of 1 to 3, and t is an average of 0 to 10 in repeating units. .)

（式中Ｒは水素原子、アルキル基、アリール基、アラルキル基、ハロゲン原子、水酸基、アルコキシ基の何れかであり、ｓは１〜３の整数、ｔは繰り返し単位の平均で０〜１０である。）これらはそれぞれ単独で用いても良いし、２種類以上を併用しても良い。

(In the formula, R is any of a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, a halogen atom, a hydroxyl group, and an alkoxy group, s is an integer of 1 to 3, and t is an average of 0 to 10 in repeating units. .) Each of these may be used alone, or two or more types may be used in combination.

Further, when the resin composition of the present invention is used for applications requiring high flame retardancy, a non-halogen flame retardant that does not substantially contain a halogen atom may be blended.

Examples of the non-halogen flame retardant include phosphorus flame retardants, nitrogen flame retardants, silicone flame retardants, inorganic flame retardants, organic metal salt flame retardants, and the like, and their use is also restricted. It may be used alone, a plurality of flame retardants of the same system may be used, and flame retardants of different systems may be used in combination.

As the phosphorus-based flame retardant, either an inorganic type or an organic type can be used. Examples of the inorganic compound include ammonium phosphates such as red phosphorus, monoammonium phosphate, diammonium phosphate, triammonium phosphate and ammonium polyphosphate, and inorganic nitrogen-containing phosphorus compounds such as phosphate amide. ..

The red phosphorus is preferably surface-treated for the purpose of preventing hydrolysis and the like, and examples of the surface treatment method include (i) magnesium hydroxide, aluminum hydroxide, zinc hydroxide, and water. A method of coating with an inorganic compound such as titanium oxide, bismuth oxide, bismuth hydroxide, bismuth nitrate or a mixture thereof, (ii) inorganic compounds such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide and titanium hydroxide, and Method of coating with a mixture of thermosetting resins such as phenol resin, (iii) Thermocurability of phenol resin or the like on a film of an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide Examples thereof include a method of double coating with a resin.

The organic phosphorus compounds include, for example, general-purpose organic phosphorus compounds such as phosphoric acid ester compounds, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphoran compounds, and organic nitrogen-containing phosphorus compounds, as well as 9,10-dihydro. -9-Oxa-10-phosphaphenanthrene-10-oxide, 10- (2,5-dihydrooxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide, 10- (2,7-) Examples thereof include cyclic organophosphorus compounds such as dihydrooxynaphthyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide and derivatives obtained by reacting the cyclic organophosphorus compounds with compounds such as epoxy resins and phenol resins.

The blending amount of these phosphorus-based flame retardants is appropriately selected depending on the type of the phosphorus-based flame retardant, other components of the resin composition, and the desired degree of flame retardancy. For example, a non-halogen flame retardant. When red phosphorus is used as a non-halogen flame retardant, it is blended in the range of 0.1 parts by mass to 2.0 parts by mass in 100 parts by mass of the resin composition containing all of the fillers and other additives. In the same way, when an organic phosphorus compound is used, it is preferably blended in the range of 0.1 parts by mass to 10.0 parts by mass, and blended in the range of 0.5 parts by mass to 6.0 parts by mass. It is more preferable to do so.

When the phosphorus-based flame retardant is used, hydrotalcite, magnesium hydroxide, boron compound, zirconium oxide, black dye, calcium carbonate, zeolite, zinc molybdate, activated charcoal, etc. may be used in combination with the phosphorus-based flame retardant. Good.

Examples of the nitrogen-based flame retardant include triazine compounds, cyanuric acid compounds, isocyanuric acid compounds, and phenothiazine, and triazine compounds, cyanuric acid compounds, and isocyanuric acid compounds are preferable.

The triazine compound includes, for example, melamine, acetoguanamine, benzoguanamine, melon, melam, succinoguanamine, ethylenedimelamine, polyphosphate melamine, triguanamine and the like, and for example, (1) guanyl melamine sulfate, melem sulfate, melam sulfate. Aminotriazine sulfate compounds such as, (2) Phenols such as phenol, cresol, xylenol, butylphenol, nonylphenol, and melamines such as melamine, benzoguanamine, acetguanamine, formguanamine and formaldehyde, (3) the above. Examples thereof include a mixture of the cocondensate of (2) and a phenol resin such as a phenol formaldehyde condensate, and (4) the above (2) and (3) further modified with tung oil, isomerized melamine oil and the like.

Examples of the cyanuric acid compound include cyanuric acid and melamine cyanuric acid.

The blending amount of the nitrogen-based flame retardant is appropriately selected depending on the type of the nitrogen-based flame retardant, other components of the resin composition, and the desired degree of flame retardancy. For example, a non-halogen flame retardant. And other fillers, additives, etc. are all blended in the range of 0.05 to 10 parts by mass, preferably in the range of 0.1 parts by mass to 5 parts by mass, out of 100 parts by mass of the resin composition. It is more preferable to do so.

When using the nitrogen-based flame retardant, a metal hydroxide, a molybdenum compound, or the like may be used in combination.

The silicone-based flame retardant can be used without particular limitation as long as it is an organic compound containing a silicon atom, and examples thereof include silicone oil, silicone rubber, and silicone resin. The blending amount of the silicone flame retardant is appropriately selected depending on the type of the silicone flame retardant, other components of the resin composition, and the desired degree of flame retardancy. For example, a non-halogen flame retardant. It is preferable to blend in the range of 0.05 to 20 parts by mass in 100 parts by mass of the resin composition containing all of the other fillers and additives. Further, when using the silicone flame retardant, a molybdenum compound, alumina or the like may be used in combination.

Examples of the inorganic flame retardant include metal hydroxides, metal oxides, metal carbonate compounds, metal powders, boron compounds, and low melting point glass.

Examples of the metal hydroxide include aluminum hydroxide, magnesium hydroxide, dolomite, hydrotalcite, calcium hydroxide, barium hydroxide, zirconium hydride and the like.

The metal oxide includes, for example, zinc molybdate, molybdenum trioxide, zinc tinate, tin oxide, aluminum oxide, iron oxide, titanium oxide, manganese oxide, zirconium oxide, zinc oxide, molybdenum oxide, cobalt oxide, and bismuth oxide. Examples thereof include chromium oxide, nickel oxide, copper oxide, and tungsten oxide.

Examples of the metal carbonate compound include zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, basic magnesium carbonate, aluminum carbonate, iron carbonate, cobalt carbonate, titanium carbonate and the like.

Examples of the metal powder include aluminum, iron, titanium, manganese, zinc, molybdenum, cobalt, bismuth, chromium, nickel, copper, tungsten, tin and the like.

Examples of the boron compound include zinc borate, zinc metaborate, barium metaborate, boric acid, and borax.

The low melting point glass includes, for example, Shipley (Boxy Brown), hydrated glass SiO2-MgO-H2O, PbO-B2O3 series, ZnO-P2O5-MgO series, P2O5-B2O3-PbO-MgO series, P-Sn- Examples thereof include glassy compounds such as OF-based, PbO-V2O5-TeO2-based, Al2O3-H2O-based, and lead borosilicate-based.

The blending amount of the inorganic flame retardant is appropriately selected depending on the type of the inorganic flame retardant, other components of the resin composition, and the desired degree of flame retardancy. For example, a non-halogen flame retardant. It is preferable to blend in the range of 0.05 parts by mass to 20 parts by mass, and in the range of 0.5 parts by mass to 15 parts by mass, out of 100 parts by mass of the resin composition containing all of the other fillers and additives. It is more preferable to mix with.

The organometallic salt-based flame retardant includes, for example, ferrocene, an acetylacetonate metal complex, an organometallic carbonyl compound, an organocobalt salt compound, an organosulfonic acid metal salt, a metal atom and an aromatic compound or a heterocyclic compound in an ionic bond or arrangement. Examples thereof include position-bonded compounds.

The blending amount of the organic metal salt-based flame retardant is appropriately selected depending on the type of the organic metal salt-based flame retardant, other components of the resin composition, and the desired degree of flame retardancy. It is preferable to blend in the range of 0.005 parts by mass to 10 parts by mass in 100 parts by mass of the resin composition containing all of the halogen-based flame retardant and other fillers and additives.

The resin composition of the present invention may contain an inorganic filler, if necessary. Examples of the inorganic filler include fused silica, crystalline silica, alumina, silicon nitride, aluminum hydroxide and the like. When the blending amount of the inorganic filler is particularly large, it is preferable to use fused silica. The molten silica can be used in either a crushed form or a spherical shape, but in order to increase the blending amount of the molten silica and suppress an increase in the melt viscosity of the molding material, it is preferable to mainly use a spherical one. Further, in order to increase the blending amount of spherical silica, it is preferable to appropriately adjust the particle size distribution of spherical silica. The filling rate is preferably high in consideration of flame retardancy, and is particularly preferably 20% by mass or more with respect to the total mass of the resin composition. When used for applications such as conductive paste, a conductive filler such as silver powder or copper powder can be used.

In addition to this, various compounding agents such as a silane coupling agent, a mold release agent, a pigment, and an emulsifier can be added to the resin composition of the present invention, if necessary.

<Use of curable resin composition>
The curable resin composition of the present invention shall be applied to semiconductor encapsulant materials, semiconductor devices, prepregs, printed circuit boards, build-up substrates, build-up films, fiber-reinforced composite materials, fiber-reinforced resin molded products, conductive pastes, and the like. Can be done.

1. 1. Semiconductor encapsulation material As a method for obtaining a semiconductor encapsulation material from the curable resin composition of the present invention, the curable resin composition is uniformly obtained by using an extruder, a feeder, a roll or the like as necessary. Examples thereof include a method of sufficiently melting and mixing until it becomes possible. At that time, fused silica is usually used as the inorganic filler, but when used as a high thermal conductivity semiconductor encapsulant for power transistors and power ICs, crystalline silica, alumina, and silicon nitride having higher thermal conductivity than fused silica are used. It is preferable to use high-filling silicon or the like, or use molten silica, crystalline silica, alumina, silicon nitride, or the like. It is preferable to use an inorganic filler in the range of 30% by mass to 95% by mass per 100 parts by mass of the curable resin composition, and among them, improvement of flame retardancy, moisture resistance and solder crack resistance, wire In order to reduce the coefficient of expansion, 70 parts by mass or more is more preferable, and 80 parts by mass or more is further preferable.

2. Semiconductor device As a method for obtaining a semiconductor device from the curable resin composition of the present invention, the semiconductor encapsulant material is cast or molded using a transfer molding machine, an injection molding machine, or the like, and further at 50 to 200 ° C. 2 A method of heating for 10 hours can be mentioned.

3. 3. Prepreg As a method for obtaining a prepreg from the curable resin composition of the present invention, a curable resin composition obtained by blending an organic solvent to form a varnish is used as a reinforcing base material (paper, glass cloth, glass non-woven fabric, aramid paper, aramid cloth). , Glass mat, glass roving cloth, etc.) and then heated at a heating temperature, preferably 50 to 170 ° C., depending on the type of solvent used. The mass ratio of the resin composition and the reinforcing base material used at this time is not particularly limited, but it is usually preferable to prepare the resin content in the prepreg to be 20% by mass to 60% by mass.

Examples of the organic solvent used here include methyl ethyl ketone, acetone, dimethylformamide, methyl isobutyl ketone, methoxypropanol, cyclohexanone, methyl cellosolve, ethyl diglycol acetate, propylene glycol monomethyl ether acetate, and the like. It can be appropriately selected depending on the application, but for example, when further producing a printed circuit board from prepylene as described below, it is preferable to use a polar solvent having a boiling point of 160 ° C. or lower, such as methyl ethyl ketone, acetone, or dimethylformamide. , It is preferable to use the non-volatile content at a ratio of 40% by mass to 80% by mass.

4. Printed circuit board As a method for obtaining a printed circuit board from the curable resin composition of the present invention, the prepregs are laminated by a conventional method, copper foils are appropriately laminated, and the temperature is 170 to 300 ° C. under a pressure of 1 to 10 MPa. Examples thereof include a method of heat-bonding for 10 minutes to 3 hours.

5. Build-up substrate As a method for obtaining a build-up substrate from the curable resin composition of the present invention, a method via steps 1 to 3 can be mentioned. In step 1, first, the curable resin composition in which rubber, a filler and the like are appropriately mixed is applied to a circuit board on which a circuit is formed by a spray coating method, a curtain coating method, or the like, and then cured. In step 2, if necessary, a circuit board coated with the curable resin composition is drilled with a predetermined through-hole portion or the like, treated with a roughening agent, and the surface thereof is washed with hot water. Concavities and convexities are formed on the substrate, and a metal such as copper is plated. In step 3, the operations of steps 1 and 2 are sequentially repeated as desired, and the resin insulating layer and the conductor layer having a predetermined circuit pattern are alternately built up to form a build-up substrate. In the above step, the through-hole portion may be drilled after the outermost resin insulating layer is formed. Further, the build-up substrate of the present invention is roughened by heat-pressing a resin-containing copper foil obtained by semi-curing the resin composition on a copper foil onto a wiring substrate on which a circuit is formed at 170 to 300 ° C. It is also possible to produce a build-up substrate by omitting the steps of forming a surface and plating.

6. Build-up film As a method of obtaining a build-up film from the curable resin composition of the present invention, for example, a curable resin composition is applied on a support film, dried, and a resin composition layer is placed on the support film. There is a method of forming. When the curable resin composition of the present invention is used as a build-up film, the film is softened under the temperature conditions of lamination (usually 70 ° C. to 140 ° C.) in the vacuum laminating method, and is applied to the circuit board at the same time as laminating the circuit board. It is important to show fluidity (resin flow) capable of filling the existing via hole or through hole with resin, and it is preferable to blend each of the above components so as to exhibit such characteristics.

Here, the diameter of the through hole of the circuit board is usually 0.1 to 0.5 mm, and the depth is usually 0.1 to 1.2 mm, and it is usually preferable to enable resin filling in this range. When laminating both sides of a circuit board, it is desirable to fill about 1/2 of the through holes.

As a specific method for producing the above-mentioned build-up film, after preparing a varnished resin composition by blending an organic solvent, the composition is applied to the surface of the support film (Y) and further heated. Alternatively, a method of drying the organic solvent by blowing hot air or the like to form the layer (X) of the curable resin composition can be mentioned.

Examples of the organic solvent used here include ketones such as acetone, methyl ethyl ketone and cyclohexanone, acetates such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate, cellosolve and butyl carbitol and the like. Carbitols, aromatic hydrocarbons such as toluene and xylene, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like are preferably used, and the non-volatile content is 30% by mass to 60% by mass. Is preferable.

The thickness of the layer (X) of the resin composition to be formed usually needs to be equal to or larger than the thickness of the conductor layer. Since the thickness of the conductor layer of the circuit board is usually in the range of 5 to 70 μm, the thickness of the resin composition layer is preferably 10 to 100 μm. The layer (X) of the resin composition in the present invention may be protected by a protective film described later. By protecting with a protective film, it is possible to prevent dust and the like from adhering to the surface of the resin composition layer and scratches.

The support film and protective film described above include polyolefins such as polyethylene, polypropylene and polyvinyl chloride, polyethylene terephthalate (hereinafter, may be abbreviated as "PET"), polyesters such as polyethylene naphthalate, polycarbonate, polyimide, and further release. Examples include metal foils such as patterns, copper foils, and aluminum foils. The support film and the protective film may be subjected to a mold release treatment in addition to the mud treatment and the corona treatment. The thickness of the support film is not particularly limited, but is usually 10 to 150 μm, and is preferably used in the range of 25 to 50 μm. The thickness of the protective film is preferably 1 to 40 μm.

The support film (Y) described above is peeled off after being laminated on a circuit board or after forming an insulating layer by heat curing. If the support film (Y) is peeled off after the resin composition layer constituting the build-up film is heat-cured, it is possible to prevent the adhesion of dust and the like in the curing step. When peeling after curing, the support film is usually subjected to a mold release treatment in advance.

A multilayer printed circuit board can be manufactured from the build-up film obtained as described above. For example, when the layer (X) of the resin composition is protected by a protective film, the layers (X) of the resin composition are peeled off, and then one side or both sides of the circuit board are brought into direct contact with the layer (X) of the resin composition. , For example, by the vacuum laminating method. The laminating method may be a batch method or a continuous method using a roll. If necessary, the build-up film and the circuit board may be preheated if necessary before laminating. As for the laminating conditions, the crimping temperature (lamination temperature) is preferably 70 to 140 ° C., and the crimping pressure is preferably 1 to 11 kgf / cm2 (9.8 × 104 to 107.9 × 104 N / m2). , It is preferable to laminate under a reduced air pressure of 20 mmHg (26.7 hPa) or less.

7. Fiber-reinforced composite material As a method for obtaining a fiber-reinforced composite material (a sheet-like intermediate material in which a resin is impregnated in a reinforcing fiber) from the curable resin composition of the present invention, each component constituting the curable resin composition is uniformly applied. Examples thereof include a method of mixing to prepare a varnish, then impregnating the reinforcing base material made of reinforcing fibers with the varnish, and then carrying out a polymerization reaction.

Specifically, the curing temperature at the time of carrying out such a polymerization reaction is preferably in the temperature range of 50 to 250 ° C., in particular, after curing at 50 to 100 ° C. to obtain a tack-free cured product, further , 120-200 ° C. is preferable.

Here, the reinforcing fiber may be any of twisted yarn, untwisted yarn, untwisted yarn and the like, but the untwisted yarn and the untwisted yarn are preferable because both the moldability and the mechanical strength of the fiber-reinforced plastic member are compatible. Further, as the form of the reinforcing fiber, one in which the fiber directions are aligned in one direction or a woven fabric can be used. For woven fabrics, plain weaves, satin weaves, and the like can be freely selected according to the part to be used and the intended use. Specific examples thereof include carbon fiber, glass fiber, aramid fiber, boron fiber, alumina fiber, and silicon carbide fiber because of their excellent mechanical strength and durability, and two or more of these can be used in combination. Among these, carbon fibers are particularly preferable from the viewpoint of improving the strength of the molded product, and various carbon fibers such as polyacrylonitrile-based, pitch-based, and rayon-based can be used. Of these, polyacrylonitrile-based ones, which can easily obtain high-strength carbon fibers, are preferable. Here, the amount of the reinforcing fiber used when impregnating the reinforcing base material made of the reinforcing fiber with the varnish to obtain the fiber-reinforced composite material is such that the volume content of the reinforcing fiber in the fiber-reinforced composite material is 40% to 85%. The amount is preferably in the range of.

8. Fiber-reinforced resin molded product As a method for obtaining a fiber-reinforced molded product (a molded product in which a sheet-like member impregnated with resin impregnated in reinforcing fibers is cured) from the curable resin composition of the present invention, a fiber aggregate is laid on a mold and described above. Using either the hand lay-up method, spray-up method, or male or female type, in which varnish is laminated in multiple layers, the base material made of reinforcing fibers is impregnated with varnish and stacked to form, and pressure is applied to the molded product. Vacuum bag method in which a flexible mold that can be made to be covered and airtightly sealed is vacuum (decompressed) molded, SMC press method in which a varnish containing reinforcing fibers is previously made into a sheet and compression molded with a mold, fibers Examples thereof include a method of producing a prepreg in which reinforcing fibers are impregnated with the varnish by an RTM method or the like in which the varnish is injected into a combined mold in which the varnish is spread, and then baking the prepreg with a large autoclave. The fiber-reinforced resin molded product obtained above is a molded product having a reinforcing fiber and a cured product of a curable resin composition. Specifically, the amount of the reinforcing fiber in the fiber-reinforced molded product is It is preferably in the range of 40% by mass to 70% by mass, and particularly preferably in the range of 50% by mass to 70% by mass from the viewpoint of strength.

9. Conductive Paste As a method for obtaining a conductive paste from the curable resin composition of the present invention, for example, a method of dispersing fine conductive particles in the curable resin composition can be mentioned. The conductive paste can be a paste resin composition for circuit connection or an anisotropic conductive adhesive depending on the type of fine conductive particles used.

Next, the present invention will be specifically described with reference to Examples and Comparative Examples. In the following, "parts" and "%" are based on mass unless otherwise specified.

Examples 1-2, Comparative Examples 1-4
Each component was blended in the ratio shown in Table 1 to obtain a curable resin composition. The gel time of the obtained curable resin composition was measured. Further, the curable resin composition was poured into a predetermined mold using a press machine and molded at a temperature of 175 ° C. for 10 minutes. The molded product was taken out from the mold and cured at a temperature of 175 ° C. for 5 hours. The obtained cured product was evaluated for dielectric constant / dielectric loss tangent, glass transition temperature, and moisture resistance reliability as follows. The results are shown in Table 2.

The raw materials used for adjusting the curable resin composition are as follows.
-Epoxy resin: Cresol novolac type epoxy resin (manufactured by DIC Corporation, "EPICLON N-655-EXP-S" epoxy equivalent: 202 g / eq.)
-Active ester: "EPICLON EXB-8" manufactured by DIC Corporation, ester equivalent: 209 g / eq.
-Phenol resin: Phenol novolac resin (manufactured by DIC Corporation, "PHENOLITE TD-2131", hydroxyl group equivalent: 104 g / eq.)
-TBP-3S: "Tetra (n-butyl) phosphonium-hydrogen-hexahydrophthalate" manufactured by Hokuko Chemical Industry Co., Ltd.
-TPP-phthalic acid: "Tetraphenylphosphonium-hydrogen-phthalate" manufactured by Hokuko Chemical Industry Co., Ltd.
・ TPP: "Triphenylphosphine" manufactured by Hokuko Chemical Industry Co., Ltd.
2E4MZ: "2-Ethyl-4-methylimidazole" manufactured by Shikoku Chemicals Corporation
-DMAP: "N, N-dimethyl-4-aminopyridine" manufactured by Koei Chemical Industry Co., Ltd.

Measurement of gel time Immediately after mixing each component in the ratio shown in Table 1 to prepare a curable resin composition, 0.15 g of the curable composition was placed on a hot plate heated to 175 ° C., and the gel was stirred with a spatula. The time until the shape was formed was measured. The same operation was repeated three times, and the average value was used for evaluation.

Measurement of Dielectric Permittivity and Dissipation Factor A cured molded product was cut into a size of 1 mm × 54 mm × 1.6 mm and used as a test piece. Test pieces stored in a room at 23 ° C. and 50% humidity for 24 hours after being vacuum-dried by heating are conformed to JIS-C-6481 and used with an impedance material analyzer "HP4291B" manufactured by Agilent Technologies, Inc. at 1 GHz. Dielectric constant and dielectric loss tangent were measured.

Measurement of glass transition temperature The cured product obtained above was cut into a size of 5 mm in width and 54 mm in length, and this was used as a test piece using a viscoelasticity measuring device (“Solid viscoelasticity measuring device RSAII” manufactured by Leometric). The temperature at which the change in viscoelasticity was maximum (the rate of change in tan δ was the largest) was evaluated as the glass transition temperature under the measurement conditions of the rectangular tension method, the frequency of 1 Hz, and the heating rate of 3 ° C./min.

Moisture resistance and reliability A cured product and ion-exchanged water were placed in a PCT container and treated at 160 ° C. for 20 hrs. Extracted chloride ions were calculated by measuring the treated water by potentiometric titration (cured resin product: 5 g, ion-exchanged water: 50 g).
⊚: less than 5 ppm 〇: 5 ppm or more and less than 10 ppm ×: 10 ppm or more

Claims (11)

A curable resin composition comprising an epoxy resin (A), an active ester (B), and a quaternary phosphonium salt carboxylate (C) as essential components. The curable resin composition according to claim 1, wherein the active ester (B) has a structure in which a phenolic hydroxyl group of a polyhydric phenol or a phenol resin is alkyl-esterified or aryl-esterified. The carboxylate (C) of the quaternary phosphonium salt has the following general formula (1).

[In the formula (1), R ^{1 to} R ⁴ each independently have a linear or branched alkyl group having 1 to 16 carbon atoms, or a phenyl which may have an aromatic cyclic substituent. It is a group. ]
The phosphonium cation represented by
The claim 1 or 2 which comprises a salt with an anion residue of an aliphatic polycarboxylic acid (c-1), an alicyclic polycarboxylic acid (c-2), or an aromatic polycarboxylic acid (c-3). Curable resin composition. The aliphatic polycarboxylic acid (c-1) has the following general formula (2-1).

[In formula (2-1), R ^{5 to} R ⁸ are independently hydrogen atoms, linear or branched alkyl groups having 1 to 4 carbon atoms, hydroxyl groups, amino groups, carboxyl groups or carboxy groups. Alkyl group]
The curable resin composition according to claim 2, which is an aliphatic polycarboxylic acid represented by. The alicyclic polycarboxylic acid (c-2) has the following general formulas (2-2) and (2-3).

[In formulas (2-2) and (2-3), R ¹⁰ represents a methylene group or an ethylene group, and R11 to R18 are independently hydrogen atoms and linear or linear atoms having 1 to 4 carbon atoms, respectively. It is a branched alkyl group or a carboxy group. ]
The curable resin composition according to claim 2, which is an alicyclic polycarboxylic acid represented by. The aromatic polycarboxylic acid (c-3) has the following general formula (2-4).

[In formula (2-4), R ^{19 to} R ²² are independently hydrogen atoms, alkyl groups, hydroxyl groups, amino groups or alkoxy groups. ]
The curable resin composition according to claim 2, which is an aromatic polycarboxylic acid represented by. Any one of claims 1 to 6, wherein the ratio of the quaternary phosphonium salt carboxylate (C) used is in the range of 0.5 to 10 parts by mass with respect to 100 parts by mass of the epoxy resin (A). The curable resin composition according to the above. A cured product of the curable composition according to any one of claims 1 to 7. A printed wiring board using the curable composition according to any one of claims 1 to 7. A semiconductor encapsulating material using the curable composition according to any one of claims 1 to 7. A build-up film using the curable composition according to any one of claims 1 to 7.