JP2022043685A - Curable resin composition, dry film, copper foil with resin, cured product and electronic component - Google Patents

Abstract

To provide a curable resin composition which gives a cured product combining a high elastic modulus, high peel strength, high heat resistance and a low dielectric loss tangent, and to provide a dry film, a copper foil with resin, a cured product and an electronic component.SOLUTION: The curable resin composition contains (A) an epoxy resin, (B) a compound having an active ester group, (C) an inorganic filler and (D) a phenoxy resin. The epoxy resin (A) contains (A1) a biphenyl tetrafunctional epoxy resin represented by general formula (1).SELECTED DRAWING: None

Description

The present invention relates to a curable resin composition, a dry film, a copper foil with a resin and a cured product thereof, and an electronic component containing the cured product, and in particular, a heat-curable curable resin composition containing an epoxy resin and a dry film. , Resin-coated copper foils and their cured products, and electronic parts containing the cured products.

In recent years, the miniaturization of electronic devices has progressed, and the size of electronic components such as printed wiring boards mounted on the electronic devices has also been reduced in size.

Conventionally, as an insulating material for an inner layer material constituting an electronic component, a prepreg obtained by impregnating a glass cloth with an epoxy resin or the like has been mainly used. However, in recent years, adhesive dry films that do not use glass cloth have been used. For example, Patent Document 1 discloses an epoxy resin composition containing an epoxy resin, an active ester compound, a triazine-containing phenol resin, a maleimide compound, and a phenoxy resin, and an adhesive film using the epoxy resin composition.

Japanese Patent No. 5396805

However, in a cured product that does not contain glass cloth, warpage is likely to occur. When the warp of the cured product becomes large, the entire electronic component also warps, resulting in circuit distortion and poor contact. In particular, the lighter, thinner, shorter and smaller the electronic component, the greater the effect of the warp of the cured product.

Therefore, it is conceivable to increase the elastic modulus of the cured product in order to suppress the warp of the cured product that does not have the glass cloth and to cope with the lightening, thinning, shortening, and miniaturization of the electronic component. However, when the elastic modulus is increased, the adhesion (peel strength) with the underlying circuit board tends to decrease.

According to the epoxy resin composition of Patent Document 1, although the roughness of the roughened surface obtained by roughening the surface of the cured product of the epoxy resin composition is relatively small, the roughened surface is relative to the plated conductor. It is disclosed that an insulating layer showing high adhesion and having a small linear expansion rate can be achieved. However, even in the epoxy resin composition of Patent Document 1, it has not been possible to achieve both peel strength and elastic modulus.

On the other hand, it is conceivable to raise the glass transition temperature of the cured product in order to improve the heat resistance. However, when the crosslink density is usually increased in order to increase the glass transition temperature, the peel strength tends to decrease.

Further, in recent years, with the adoption of high-speed communication, that is, with the increase in high frequency, the transmission loss tends to increase, so that the insulating material of electronic components is required to have a low dielectric loss tangent capable of suppressing the transmission loss.

In view of the above problems, an object of the present invention is to obtain a curable resin composition, a dry film, a copper foil with a resin, and a cured product, wherein the obtained cured product has a high elastic modulus, high peel strength, high heat resistance, and low dielectric loss tangent. And to provide electronic components.

The present inventors have made diligent studies to achieve the above object. As a result, in the curable resin composition containing (A) an epoxy resin, (B) a compound having an active ester group, (C) an inorganic filler and (D) a phenoxy resin, the (A) epoxy resin is a predetermined biphenyl 4 It has been found that all the above problems can be solved by including the functional epoxy resin.

（一般式（１）において、Ｒ^１およびＲ^２は、それぞれ独立してメチル基、メトキシ基もしくはハロゲン原子を表し、ｍおよびｎは、それぞれ独立して０～３の整数を表す。）で表されるビフェニル４官能型エポキシ樹脂を含むことを特徴とする硬化性樹脂組成物によって達成されることが見出された。 That is, the object of the present invention is
(A) Epoxy resin,
(B) A compound having an active ester group,
A curable resin composition containing (C) an inorganic filler and (D) a phenoxy resin.
The (A) epoxy resin is the (A1) general formula (1).

(In the general formula (1), R ¹ and R ² independently represent a methyl group, a methoxy group or a halogen atom, and m and n independently represent an integer of 0 to 3). It has been found that this is achieved by a curable resin composition comprising a biphenyl tetrafunctional epoxy resin to be made.

Further, in the curable resin composition of the present invention, the ratio of the total amount of epoxy groups in (A) epoxy resin to the total amount of ester groups in (B) the compound having active ester groups is 0.2 or more and 0.6 or less. It is preferable to have.

Further, the blending ratio of the biphenyl tetrafunctional epoxy resin represented by the general formula (1) to the total amount of the (A) epoxy resin and (B) the compound having an active ester group is 3. It is preferably in the range of 0% by mass or more and 15.0% by mass or less.

Moreover, the (D) phenoxy resin preferably contains (D1) a biphenyl skeleton-containing phenoxy resin and / or (D2) a fluorene-type skeleton-containing phenoxy resin.

（式（２）中、Ｘ_１はそれぞれ独立的にベンゼン環またはナフタレン環を有する基であり、ｋは０または１を表し、ｎは繰り返し単位の平均で０．２５～１．５である）で表される化合物であることが好ましい。 Further, (B) the compound having an active ester group is the following general formula (2).

(In formula (2), X ₁ is a group independently having a benzene ring or a naphthalene ring, k represents 0 or 1, and n is an average of 0.25 to 1.5 in repeating units.) It is preferably a compound represented by.

（式（３）中、Ｘ_２はそれぞれ独立的に下記式（４）： Further, the compound having the (B) active ester group is described in the following general formula (3):

(In the formula (3), X ₂ is independently the following formula (4):

で表される基または下記式（５）：

で表される基であり、
ｍは１～６の整数であり、ｎはそれぞれ独立的に１～５の整数であり、ｑはそれぞれ独立的に１～６の整数であり、
式（４）中、ｋはそれぞれ独立的に１～５の整数であり、
式（５）中、Ｙは上記式（４）で表される基（ｋはそれぞれ独立的に１～５の整数）であり、ｔはそれぞれ独立的に０～５の整数である）
で表される構造部位を有し、その両末端が一価のアリールオキシ基である構造を有する化合物であることが好ましい。

Group represented by or the following formula (5):

It is a group represented by
m is an integer of 1 to 6, n is an integer of 1 to 5 independently, and q is an integer of 1 to 6 independently.
In equation (4), k is an integer of 1 to 5 independently.
In the formula (5), Y is a group represented by the above formula (4) (k is an integer of 1 to 5 independently), and t is an integer of 0 to 5 independently).
It is preferable that the compound has a structural moiety represented by and has a structure in which both ends thereof are monovalent aryloxy groups.

Moreover, the object of the present invention is to have the above-mentioned curable resin composition as a resin layer.
A copper foil with a resin, which comprises the above-mentioned curable resin composition as a resin layer on a copper foil or a copper foil with a carrier.
It is also achieved by the above-mentioned curable resin composition, the cured product of the resin layer of the dry film, or the cured product of the resin layer of the copper foil with resin, and the electronic component characterized by having the above-mentioned cured product.

According to the curable resin composition, the dry film, and the copper foil with resin of the present invention, the obtained cured product has high elastic modulus, high peel strength, high heat resistance, and low dielectric loss tangent.

（一般式（１）において、Ｒ^１およびＲ^２は、それぞれ独立してメチル基、メトキシ基もしくはハロゲン原子を表し、ｍおよびｎは、それぞれ独立して０～３の整数を表し、好ましくは、ｍおよびｎは共に０である。）で表されるビフェニル４官能型エポキシ樹脂（以下、単に（Ａ１）一般式（１）で表されるビフェニル４官能型エポキシ樹脂ともいう）を含む。 <Curable resin composition>
The curable resin composition of the present invention is
(A) Epoxy resin,
(B) A compound having an active ester group,
A curable resin composition containing (C) an inorganic filler and (D) a phenoxy resin.
The (A) epoxy resin is the (A1) general formula (1).

(In the general formula (1), R ¹ and R ² independently represent a methyl group, a methoxy group or a halogen atom, and m and n independently represent an integer of 0 to 3, preferably. Both m and n are 0), and a biphenyl tetrafunctional epoxy resin (hereinafter, also simply referred to as (A1) a biphenyl tetrafunctional epoxy resin represented by the general formula (1)) is included.

With the curable resin composition having such a structure, it is possible to obtain a cured product having high elastic modulus, high peel strength, high heat resistance, and low dielectric loss tangent. That is, in the composition (A1) which does not contain the biphenyl tetrafunctional epoxy resin represented by the general formula (1) and (B) the composition which does not contain the compound having an active ester group, the glass transition temperature is high and the elastic modulus is high. In the composition of the present invention, a high elastic modulus and a high peel are obtained by combining the components (A1), (B), (C) and (D). It is possible to obtain a cured product having both strength and high heat resistance and low dielectrically tangent.

[(A) Epoxy resin]
The curable resin composition of the present invention contains one or more kinds of (A) epoxy resins, and (A) the epoxy resin is (A1) a biphenyl tetrafunctional epoxy resin represented by the general formula (1). include.

が挙げられる。 (A1) Examples of the biphenyl tetrafunctional epoxy resin represented by the general formula (1) include the following compounds.

Can be mentioned.

Examples of the biphenyl tetrafunctional epoxy resin represented by the general formula (1) in which m and n in the general formula (1) are both 0 are the following compounds.

が挙げられる。

Can be mentioned.

Further, the biphenyl tetrafunctional epoxy resin represented by (A1) general formula (1) oxidizes the allyl group after glycidylating the phenolic hydroxyl group with epihalohydrin from, for example, a compound having an allyl group and a phenolic hydroxyl group. It can be produced by a method of forming an epoxy ring, a method of allylating a phenolic hydroxyl group and then oxidizing all allylic groups to form an epoxy ring, and the like. Specifically, it can be produced by the method described in JP-A-63-142019 and JP-A-2016-204647.

（式（６）中、Ａｒ_１はそれぞれ独立的に下記式

で表される基（式（７）～（８）中、Ｒは、それぞれ独立的に、水素、炭素数１～６個のアルキル基、炭素数１～６個のアルコキシ基およびオキシラニルメトキシ基のいずれかである）であり、
Ａｒ_２はそれぞれ独立的に下記式

で表される基（式（９）～（１０）中、Ｒは、それぞれ独立的に、水素および炭素数１～６個のアルキル基のいずれかである）であり、
Ａｒ_３はそれぞれ独立的に下記式

で表される基（式（１１）～（１４）中、Ｒは、それぞれ独立的に、水素、炭素数１～６個のアルキル基、炭素数１～６個のアルコキシ基およびオキシラニルメトキシ基のいずれかである）であり、
ｎは０から１５の整数である）で表されるエポキシ樹脂（以下、単に一般式（６）で表されるエポキシ樹脂ともいう）を含むことが好ましい。 In addition to the biphenyl tetrafunctional epoxy resin represented by the above (A1) general formula (1), the (A) epoxy resin contained in the curable resin composition of the present invention is further general formula (6).

(In equation (6), Ar ₁ is independently the following equation.

In the groups represented by (formulas (7) to (8), R is independently hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and oxylanylmethoxy. Is one of the groups)
Ar ₂ is independently the following formula

Is a group represented by (in formulas (9) to (10), R is independently one of hydrogen and an alkyl group having 1 to 6 carbon atoms).
Ar ₃ is independently the following formula

In the groups represented by (formulas (11) to (14), R is independently hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and oxylanylmethoxy. Is one of the groups)
It is preferable to include an epoxy resin represented by (n is an integer from 0 to 15) (hereinafter, also simply referred to as an epoxy resin represented by the general formula (6)).

Commercially available products of the epoxy resin obtained by the formula (1) include NC-3000, NC-3000-L, NC-3000-H, NC-3000-FH-75M, NC-3100, CER-3000-. L, NC-2000-L, NC-3500 (all manufactured by Nippon Kayaku Co., Ltd.), ESN-475V (manufactured by Nittetsu Chemical & Materials Co., Ltd.) and the like can be mentioned.

In addition to the above-mentioned (A1) biphenyl tetrafunctional epoxy resin represented by the general formula (1) and the epoxy resin represented by the general formula (6) which is an optional component, it is contained in the curable resin composition of the present invention. (A) The epoxy resin may contain an additional epoxy resin.

(A1) Further epoxy resins other than the biphenyl tetrafunctional epoxy resin represented by the general formula (1) and the epoxy resin represented by the general formula (6) are represented by (A1) the general formula (1). As long as it does not correspond to the biphenyl tetrafunctional epoxy resin and the epoxy resin represented by the general formula (6), any epoxy resin having one or more epoxy groups can be used, and an epoxy group is preferably used. Examples thereof include an epoxy resin having one or more, more preferably a bifunctional epoxy resin having two epoxy groups in the molecule, a polyfunctional epoxy resin having three or more epoxy groups in the molecule, and the like. It may be a hydrogenated epoxy resin.

In the curable resin composition of the present invention, from the viewpoint of imparting a low dielectric loss tangent to the cured product of the curable resin composition, the blending amount of the (A) epoxy resin is 100, which is the non-volatile content in the curable resin composition. In terms of mass%, it is preferably 20% by mass or less, and more preferably 15% by mass or less. Further, from the viewpoint of the strength of the cured product, the lower limit is preferably 1% by mass or more, and more preferably 3% by mass or more.

Further, the blending ratio of the biphenyl tetrafunctional epoxy resin represented by the general formula (1) to the total amount of the (A) epoxy resin and (B) the compound having an active ester group is 3. It is preferably in the range of 0% by mass or more and 15.0% by mass or less, and more preferably 3.0% by mass or more and 11.0% by mass or less.

The blending ratio of the biphenyl tetrafunctional epoxy resin represented by (A1) general formula (1) to the total amount of (A) epoxy resin and (B) compound having an active ester group is within the above range. A cured product having high peel strength can be obtained.

The curable resin composition of the present invention may contain a thermosetting resin in addition to the epoxy compound as long as the effects of the present invention are not impaired, and may contain, for example, an isocyanate compound, a blocked isocyanate compound, an amino resin, and a benzo. Known and commonly used thermosetting resins such as oxazine resins, carbodiimide resins, cyclocarbonate compounds, polyfunctional oxetane compounds, episulfide resins, and maleimide resins can be used.

[(B) Compound having active ester group]
The curable resin composition of the present invention contains (A) a compound having an active ester group as a curing agent for an epoxy resin.

(B) The compound having an active ester group is a compound having one or more, preferably two or more active ester groups in one molecule. A compound having an active ester group can generally be obtained by a condensation reaction between a carboxylic acid compound and a hydroxy compound. Among them, a compound having an active ester group obtained by using a phenol compound or a naphthol compound as the hydroxy compound is preferable. Examples of the phenol compound or naphthol compound include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthalin, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, fluoroglucin, benzenetriol , Dicyclopentadienyldiphenol, phenol novolac and the like. Further, as the compound (B) having an active ester group, a naphthalenediol alkyl / benzoic acid type may be used. (B) As the compound having an active ester group, one kind may be used alone, or two or more kinds may be used in combination. (B) As the compound having an active ester group, a compound having any one of benzene, α-naphthol, β-naphthol and a dicyclopentadiene skeleton is preferable.

(B) Among the compounds having an active ester group, the compounds having the following active ester groups (B1) and (B2) can be preferably used.

The (B1) compound having an active ester group includes (b1) a phenol resin having a molecular structure in which phenols are knotted via an aliphatic cyclic hydrocarbon group, (b2) an aromatic dicarboxylic acid or a halide thereof, and (b2) an aromatic dicarboxylic acid or a halide thereof. b3) It has a structure obtained by reacting an aromatic monohydroxy compound. The amount of the phenolic hydroxyl group in the (b1) phenolic resin is 0.05 to 0.75 mol with respect to 1 mol of the carboxyl group or the acid halide in the (b2) aromatic dicarboxylic acid or its halide, and the above (b3). Those having a structure obtained by reacting an aromatic monohydroxy compound at a ratio of 0.25 to 0.95 mol are preferable.

Here, in the (b1) phenol resin, 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 structures obtained by subjecting them to a double addition reaction with phenols. Here, examples of the phenols include unsubstituted phenols and substituted phenols in which one or more substituted alkyl groups, alkenyl groups, allyl groups, aryl groups, aralkyl groups, halogen groups and the like are substituted. Specific examples of the substituted phenol include cresol, xylenol, ethylphenol, isopropylphenol, butylphenol, octylphenol, nonylphenol, vinylphenol, isopropenylphenol, allylphenol, phenylphenol, benzylphenol, chlorphenol, bromphenol, naphthol, and dihydroxynaphthalene. Etc. are exemplified, but the present invention is not limited to these. Further, a mixture of these may be used. Of these, unsubstituted phenol is particularly preferable because of its excellent fluidity and curability.

Specific examples of the unsaturated alicyclic hydrocarbon compound include dicyclopentadiene, tetrahydroindene, 4-vinylcyclohexene, 5-vinylnorbona-2-ene, α-pinene, β-pinene, and limonene. Can be mentioned. 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 formability and the like, it is desirable that the product has a purity of 90% by mass or more of dicyclopentadiene.

Next, the (b2) aromatic dicarboxylic acid or its halide 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 acid compounds, acid odorants and acid iodides. Among these, the acid chloride of an aromatic dicarboxylic acid is preferable from the viewpoint of particularly good reactivity, and the dichloride of isophthalic acid and the dichloride of terephthalic acid are preferable, and the dichloride of isophthalic acid is particularly preferable.

Next, as the (b3) aromatic monohydroxy compound, for example, phenol; alkylphenols such as o-cresol, m-cresol, p-cresol, 3,5-xylenol; o-phenylphenol, p-phenylphenol, Aralkylphenols 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 because the dielectric loss tangent of the cured product is low.

（式（２）中、Ｘ_１はベンゼン環またはナフタレン環を有する基であり、ｋは０または１を表し、ｎは繰り返し単位の平均値で０．０５～２．５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、かつ、有機溶剤に溶解させた際の溶液粘度が低くなる点から好ましい。前記ベンゼン環またはナフタレン環を有する基は、特に限定されず、フェニル基、ナフチル基等でもよく、また、他の原子を介してベンゼン環またはナフタレン環が分子末端に結合していてもよく、置換基を有していてもよい。また、（Ｂ１）活性エステル化合物は、その分子末端にナフタレン環を有するものであることが好ましい。 The (B1) active ester compound has a structure obtained by reacting (b1) a phenol resin, (b2) an aromatic dicarboxylic acid or a halide thereof, and (b3) an aromatic monohydroxy compound, but in particular. , The following general formula (2)

(In formula (2), X ₁ is a group having 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 2.5.)
The structure represented by is particularly preferable because the dielectric loss tangent of the cured product is low and the solution viscosity when dissolved in an organic solvent is low. The group having a benzene ring or a naphthalene ring is not particularly limited, and may be a phenyl group, a naphthyl group, or the like, or a benzene ring or a naphthalene ring may be bonded to the molecular terminal via another atom, and is substituted. It may have a group. Further, the (B1) active ester compound preferably has a naphthalene ring at the molecular terminal thereof.

In particular, in the above general formula (2), the value of n, that is, the one in which the average value of the repeating unit is in the range of 0.25 to 1.5 has a low solution viscosity and is easy to manufacture into a dry film for build-up. It is preferable from the point of view. Further, in the above general formula (2), it is preferable that the value of k is 0 from the viewpoint of high heat resistance and low dielectric loss tangent.

Here, n in the above general formula (2) can be obtained as follows.

[How to find n in general formula (2)]
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 general formula (2) as the average molecular weight.

(GPC measurement conditions)
Measuring device: "HLC-8220 GPC" manufactured by Tosoh Co., Ltd.,
Column: Tosoh guard column "HXL-L"
+ "TSK-GEL G2000HXL" manufactured by Tosoh
+ "TSK-GEL G2000HXL" manufactured by Tosoh
+ "TSK-GEL G3000HXL" manufactured by Tosoh
+ "TSK-GEL G4000HXL" manufactured by Tosoh
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 rate: 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
"A-1000" manufactured by Tosoh
Tosoh "A-2500"
"A-5000" manufactured by Tosoh
Tosoh "F-1"
Tosoh "F-2"
Tosoh "F-4"
"F-10" manufactured by Tosoh
Tosoh "F-20"
Tosoh "F-40"
Tosoh "F-80"
"F-128" manufactured by Tosoh
Sample: A solution of 1.0% by mass in tetrahydrofuran in terms of resin solid content filtered through a microfilter (50 μl).

The method for reacting (b1) a phenol resin, (b2) an aromatic dicarboxylic acid or a halide thereof, and (b3) an aromatic monohydroxy compound specifically reacts each of these components in the presence of an alkaline catalyst. Can be made to.

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 the state of an aqueous solution and the productivity is improved.

Specifically, in the reaction, (b1) a phenol resin, (b2) an aromatic dicarboxylic acid or a halide thereof, and (b3) an aromatic monohydroxy compound are mixed in the presence of an organic solvent, and the alkaline catalyst or the same thereof is mixed. Examples thereof include a method of reacting the aqueous solution while continuously or intermittently dropping it. At that time, the concentration of the aqueous solution of the alkaline catalyst is preferably in the range of 3.0 to 30%. Further, examples of the organic solvent that can be used here include toluene and dichloromethane.

After completion of the reaction, if an aqueous solution of an alkaline catalyst is used, the reaction solution is statically separated, the aqueous layer is removed, and the remaining organic layer is repeated until the washed aqueous layer becomes almost neutral. The desired resin can be obtained.

The compound having the active ester group of (B1) thus obtained is usually obtained as an organic solvent solution, and therefore, when used as a varnish for a laminated board or a dry film for build-up, other compounding components as it is. And further, the amount of the organic solvent can be appropriately adjusted to produce the desired curable resin composition. The active ester compound (B1) is characterized by having a low melt viscosity when dissolved in an organic solvent to form a resin solution. Specifically, an active ester group of a toluene solution having a solid content of 65% is used. The solution viscosity of the compound having it is 300 to 10,000 mPa · s (25 ° C.).

で表される構造部位を有し且つその両末端が一価のアリールオキシ基である構造を有するものである。 The compound having the active ester group of (B2) has the following general formula (3):

It has a structure site represented by and has a structure in which both ends thereof are monovalent aryloxy groups.

で表される基または下記式（５）：

で表される基であり、ｍは１～６の整数であり、ｎはそれぞれ独立的に１～５の整数であり、ｑはそれぞれ独立的に０～６の整数であり、式（４）中、ｋはそれぞれ独立的に１～５の整数であり、式（５）中、Ｙは上記式（４）で表される基（ｋはそれぞれ独立的に１～５の整数）であり、ｔはそれぞれ独立的に０～５の整数である）
（Ｂ２）の活性エステル基を有する化合物は、前記一般式（３）中の

で表される部分構造が、水酸基当量が１７０～２００グラム／当量の変性ナフタレン化合物の由来構造であることが好ましい。 (In the formula (3), X ₂ is independently the following formula (4):

Group represented by or the following formula (5):

In the group represented by, m is an integer of 1 to 6, n is an integer of 1 to 5 independently, and q is an integer of 0 to 6 independently. In the formula (5), Y is a group represented by the above formula (4) (k is an integer of 1 to 5 independently). t is an integer of 0 to 5 independently)
The compound having the active ester group of (B2) is described in the general formula (3).

It is preferable that the partial structure represented by (1) is the derived structure of the modified naphthalene compound having a hydroxyl group equivalent of 170 to 200 g / equivalent.

In the formula (3), in order to clarify the relationship between m and n, some patterns are exemplified below, but the compound having the active ester group of (B2) is not limited thereto.

For example, when m = 1, the formula (3) represents the structure of the following formula (3-I).

In the formula (3-I), n is an integer of 1 to 5, and when n is 2 or more, q is an integer of 0 to 6 independently.

Further, for example, when m = 2, the formula (3) represents the structure of the following formula (3-II).

In the formula (3-II), n is an integer of 1 to 5 independently, and when n is 2 or more, q is an integer of 0 to 6 independently.

Since the compound having the active ester group of (B2) has a naphthylene ether structural moiety in the molecular main skeleton, more excellent heat resistance and flame retardancy can be imparted to the cured product, and the structural moiety is represented by the following formula (B2). Since it has a structure bonded at the structural portion represented by 15), the cured product can be provided with excellent dielectric properties. Further, in the structure of the compound having the active ester group of (B2), by adopting an aryloxy group as the structure of both ends, the heat-resistant decomposition property of the cured product can be improved to a sufficiently high level even in the use of a multilayer printed circuit board. can get.

The compound having the active ester group (B2) is preferably a compound having a softening point in the range of 100 to 200 ° C., particularly preferably in the range of 100 to 190 ° C., from the viewpoint of excellent heat resistance of the cured product.

Among the compounds having the active ester group of (B2), m in the formula (3) may be an integer of 1 to 6. Among them, those in which m is an integer of 1 to 5 are preferable. Further, n in the equation (3) may be an integer of 1 to 5 independently. Among them, those in which n is an integer of 1 to 3 are preferable.

In the formula (3), the relationship between m and n is described just in case. For example, when m is an integer of 2 or more, n of 2 or more occurs, but in that case, n is an independent value. be. That is, they may have the same value or different values as long as they are within the numerical range of n.

In the compound having the active ester group of (B2), when q is 1 or more in the formula (3), X ₂ may be substituted at any position in the naphthalene ring structure.

Examples of the aryloxy group at both ends of the structure are those derived from monohydric phenolic compounds such as phenol, cresol, pt-butylphenol (paratershary butylphenol), 1-naphthol, and 2-naphthol. Among them, a phenoxy group, a tolyloxy group or a 1-naphthyloxy group is preferable, and a 1-naphthyloxy group is more preferable, from the viewpoint of thermostable decomposition of the cured product.

Hereinafter, the method for producing the compound having the active ester group of (B2) will be described in detail.

The method for producing the compound having the active ester group of (B2) is a step of reacting a dihydroxynaphthalene compound and a benzyl alcohol in the presence of an acid catalyst to obtain a benzyl-modified naphthalene compound (hereinafter, this step is referred to as "step 1"). (May be abbreviated as), then a step of reacting the obtained benzyl-modified naphthalene compound with an aromatic dicarboxylate compound and a monovalent phenolic compound (hereinafter, this step may be abbreviated as "step 2"). There is) and.

That is, first, in step 1, the dihydroxynaphthalene compound and benzyl alcohol are reacted in the presence of an acid catalyst to have a naphthylene structure as a main skeleton and having phenolic hydroxyl groups at both ends thereof, and the naphthylene structure. A benzyl-modified naphthalene compound having a structure in which a benzyl group is bonded in a pendant shape on an aromatic nucleus can be obtained. Here, it should be noted that, in general, when a dihydroxynaphthalene compound is naphthylene etherified under an acid catalyst, it is extremely difficult to adjust the molecular weight and the molecular weight becomes high, whereas the above-mentioned production method is benzyl alcohol. By using the above in combination, such a high molecular weight increase can be suppressed, and a resin suitable for electronic material applications can be obtained.

Further, by adjusting the amount of benzyl alcohol used, in addition to being able to adjust the content of the benzyl group in the target benzyl-modified naphthalene compound, it is also possible to adjust the melt viscosity itself of the benzyl-modified naphthalene compound. Become. That is, usually, the reaction ratio between the dihydroxynaphthalene compound and benzyl alcohol is 1 / 0.1 to 1 in terms of the reaction ratio between the dihydroxynaphthalene compound and benzyl alcohol (dihydroxynaphthalene compound) / (benzyl alcohol) on a molar basis. It can be selected from the range of 1/10, but the reaction ratio of the dihydroxynaphthalene compound to benzyl alcohol (dihydroxynaphthalene compound) is based on a molar basis from the balance between heat resistance, flame retardancy, dielectric property, and heat decomposition property. The / (benzyl alcohol) is preferably in the range of 1 / 0.5 to 1 / 4.0.

The dihydroxynaphthalene compounds that can be used here are, for example, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7. -Dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene and the like can be mentioned. Among these, 1,6-dihydroxynaphthalene is obtained because the cured product of the obtained benzyl-modified naphthalene compound has better flame retardancy, and the dielectric loss tangent of the cured product is lowered and the dielectric properties are improved. Alternatively, 2,7-dihydroxynaphthalene is preferable, and 2,7-dihydroxynaphthalene is more preferable.

The acid catalyst that can be used in the reaction between the dihydroxynaphthalene compound and benzyl alcohol in step 1 is, for example, an inorganic acid such as phosphoric acid, sulfuric acid or hydrochloric acid, oxalic acid, benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid or fluoromethane. Examples thereof include organic acids such as sulfonic acid, Friedelcrafts catalysts such as aluminum chloride, zinc chloride, ferric chloride, ferric chloride and diethylsulfuric acid.

The amount of the acid catalyst used can be appropriately selected depending on the target modification rate and the like. For example, in the case of an inorganic acid or an organic acid, 0.001 to 5. It is in the range of 0 parts by mass, preferably 0.01 to 3.0 parts by mass, and in the case of a Friedel-Crafts catalyst, 0.2 to 3.0 mol, preferably 0.5 parts, relative to 1 mol of the dihydroxynaphthalene compound. The range is preferably in the range of about 2.0 mol.

The reaction between the dihydroxynaphthalene compound and benzyl alcohol in the above step 1 can be carried out without a solvent, or can be carried out under a solvent from the viewpoint of enhancing the uniformity in the reaction system. Examples of such a solvent include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monopropyl ether. Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether and other ethylene glycol and diethylene glycol mono or diether; non-polar aromatic solvents such as benzene, toluene and xylene; non-polar aromatic solvents such as dimethylformamide and dimethylsulfoxide. Protonic polar solvent; chlorobenzene and the like can be mentioned.

The specific method for carrying out the reaction in step 1 is to dissolve the dihydroxynaphthalene compound, benzyl alcohol and the acid catalyst in the absence of a solvent or in the presence of the solvent, and the temperature is about 60 to 180 ° C., preferably about 80 to 160 ° C. It can be done under temperature conditions. The reaction time is not particularly limited, but is preferably 1 to 10 hours. Therefore, the reaction can be specifically carried out by holding the temperature for 1 to 10 hours. Further, it is preferable to distill off the water generated during the reaction to the outside of the system using a fractional tube or the like because the reaction proceeds rapidly and the productivity is improved.

Further, when the obtained benzyl-modified naphthalene compound is heavily colored, an antioxidant or a reducing agent may be added to the reaction system in order to suppress it. Examples of the antioxidant include hindered phenol compounds such as 2,6-dialkylphenol derivatives, divalent sulfur compounds, and phosphite ester compounds containing a trivalent phosphorus atom. Examples of the reducing agent include hypophosphorous acid, phosphorous acid, thiosulfate, sulfurous acid, hydrosulfite or salts thereof.

After completion of the reaction, the acid catalyst can be removed by neutralization treatment, washing treatment or decomposition, and the target resin having a phenolic hydroxyl group can be separated by general operations such as extraction and distillation. The neutralization treatment and the washing treatment may be carried out according to a conventional method, and for example, basic substances such as sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia, triethylenetetramine and aniline can be used as the neutralizing agent.

Here, specific examples of the aromatic dicarboxylic acid compound include phthalic acid, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid. Examples include the acidified product of. Of these, isophthalic acid chloride and terephthalic acid chloride are preferable from the viewpoint of the balance between solvent solubility and heat resistance.

Specific examples of the monovalent phenolic compound include phenol, cresol, pt-butylphenol, 1-naphthol, 2-naphthol and the like. Of these, phenol, cresol, and 1-naphthol are preferable because they have good reactivity with carboxylic acid chloride, and 1-naphthol is more preferable because they have good thermal decomposition resistance.

Here, in the method of reacting the benzyl-modified naphthalene compound, the aromatic dicarboxylate compound, and the monohydric phenol-based compound, specifically, each of these components can be reacted in the presence of an alkaline 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 the state of an aqueous solution and the productivity is improved.

Specifically, the reaction can be carried out by mixing the above-mentioned components in the presence of an organic solvent and continuously or intermittently dropping the alkaline catalyst or an aqueous solution thereof. At that time, the concentration of the aqueous solution of the alkaline catalyst is preferably in the range of 3.0 to 30% by mass. Further, examples of the organic solvent that can be used here include toluene, dichloromethane, chloroform and the like.

After completion of the reaction, if an aqueous solution of an alkaline catalyst is used, the reaction solution is statically separated, the aqueous layer is removed, and the remaining organic layer is repeated until the washed aqueous layer becomes almost neutral. The desired resin can be obtained.

The compound having the active ester group of (B2) thus obtained is preferable when the softening point is 100 to 200 ° C. because the solubility in an organic solvent is high.

(B) The upper limit of the compounding amount of the compound having an active ester group is preferably 50% by mass or less from the viewpoint of the strength of the cured product when the non-volatile content in the curable resin composition is 100% by mass. , 40% by mass or less, and particularly preferably 30% by mass or less. Further, since a cured product having a lower dielectric loss tangent can be obtained, the lower limit is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 13% by mass or more.

In the curable resin composition of the present invention, a cured product having high heat resistance (glass transition temperature (Tg)), low dielectric loss tangent and low coefficient of linear thermal expansion can be obtained. Although the detailed mechanism is not clear, when the proportion of the compound having an active ester group, preferably the compound having an active ester group having the structure of the above general formula (2) or (3) is increased, the structure of the active ester, that is, It is considered that the glass transition temperature is improved because the movement of the chain portion between the cross-linking points is controlled by increasing the volume ratio of the aromatic ester structure which is rigid and has high molecular orientation.

Further, in order to obtain a cured product having both high heat resistance and low dielectric adjacency from the curable resin composition of the present invention, a compound having (B) an active ester group, which is the total amount of epoxy groups in (A) an epoxy resin. The ratio to the total amount of ester groups in the above is preferably 1.0 or less, more preferably 0.60 or less, and particularly preferably 0.20 or more and 0.50 or less.

The total amount of the above-mentioned epoxy groups is determined by dividing the blending amount (nonvolatile content conversion) of the (A) epoxy resin contained in the curable resin composition of the present invention by the epoxy equivalent of the (A) epoxy resin. Can be done. The total amount of the active ester group of the compound having the (B) active ester group is the blending amount (in terms of non-volatile content) of the compound having the (B) active ester group contained in the curable resin composition of the present invention. B) It can be obtained by dividing by the active ester equivalent of the compound having an active ester group.

The (A) epoxy resin and (B) the compound having an active ester group may each contain a plurality of types of compounds as described later, but in that case, the compounding amount is epoxy for each compound. Divide by the equivalent or the active ester equivalent to determine the total amount of epoxy groups or the total amount of ester groups.

The curable resin composition of the present invention may contain a curing agent other than the compound (B) having an active ester group as long as the effect of the present invention is not impaired. For example, a compound having a phenolic hydroxyl group, poly. Examples thereof include carboxylic acids and their acid anhydrides, compounds having a cyanate ester group, and alicyclic olefin polymers.

[(C) Inorganic filler]
The curable resin composition of the present invention contains (C) an inorganic filler. (C) By containing the inorganic filler, the curing shrinkage of the obtained cured product is suppressed, the CTE (coefficient of thermal expansion) is lowered, and the adhesion, hardness, and thermal strength with the conductor layer such as copper around the insulating layer are obtained. It is possible to improve thermal characteristics such as crack resistance by combining the above. (C) Conventionally known inorganic fillers can be used as the inorganic fillers, and the inorganic fillers are not limited to specific ones. Constituent pigments such as talc, clay, Neuburg silica soil particles, boehmite, magnesium carbonate, calcium carbonate, titanium oxide, aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, calcium zirconate, copper, tin, zinc, nickel, Examples thereof include metal powders such as silver, palladium, aluminum, iron, cobalt, gold and platinum. (C) The inorganic filler is preferably spherical particles. Among them, silica is preferable, and it is possible to suppress the curing shrinkage of the cured product of the curable resin composition, obtain a lower CTE, and improve properties such as adhesion and hardness. (C) The average particle size (median diameter, D50) of the inorganic filler is preferably 0.01 to 10 μm. The inorganic filler (C) is preferably silica having an average particle size of 0.01 to 3 μm. In the present specification, the average particle size of the (C) inorganic filler is an average particle size including not only the particle size of the primary particles but also the particle size of the secondary particles (aggregates). It can be obtained by a laser diffraction type particle size distribution measuring device and a measuring device by a dynamic light scattering method. Examples of the measuring device by the laser diffraction method include Microtrac MT3300EXII manufactured by Microtrac Bell, and examples of the measuring device by the dynamic light scattering method include Nanotrac Wave II UT151 manufactured by Microtrac Bell.

(C) The inorganic filler is preferably a surface-treated inorganic filler. As the surface treatment, a surface treatment with a coupling agent or a surface treatment without introducing an organic group such as an alumina treatment may be performed. (C) The surface treatment method of the inorganic filler is not particularly limited, and a known and commonly used method may be used, and a surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group, etc. (C) The surface of the inorganic filler may be treated.

(C) The surface treatment of the inorganic filler is preferably a surface treatment with a coupling agent. As the coupling agent, a silane-based, titanate-based, aluminate-based, zircoaluminate-based, or other coupling agent can be used. Of these, a silane-based coupling agent is preferable. Examples of such silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N- (2-aminomethyl) -3-aminopropylmethyldimethoxysilane, and N- (2-aminoethyl) -3-amino. Propyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxy) Cyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, etc. can be mentioned, which may be used alone or in combination. Can be used. It is preferable that these silane-based coupling agents are previously immobilized on the surface of the inorganic filler by adsorption or reaction. Here, the treatment amount of the coupling agent with respect to 100 parts by mass of the inorganic filler is, for example, 0.1 to 10 parts by mass, preferably 0.5 to 10 parts by mass.

As the curable reactive group, a thermosetting reactive group is preferable. Examples of the thermosetting reactive group include a hydroxyl group, a carboxyl group, an isocyanate group, an amino group, an imino group, an epoxy group, an oxetanyl group, a mercapto group, a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an ethoxyethyl group and an oxazolin group. Can be mentioned. Of these, at least one of an amino group and an epoxy group is preferable. The surface-treated inorganic filler may have a photocurable reactive group in addition to the thermosetting reactive group.

The surface-treated inorganic filler may be contained in the resin layer from the curable resin composition in the surface-treated state, and the curable resin composition forming the resin layer is surface-treated with the inorganic filler. The inorganic filler may be surface-treated in the curable resin composition by blending the agent separately, but it is preferable to blend the inorganic filler which has been surface-treated in advance. By blending the inorganic filler that has been surface-treated in advance, it is possible to prevent deterioration of crack resistance and the like due to the surface treatment agent that may remain in the surface treatment when the inorganic filler is blended separately. In the case of surface treatment in advance, it is preferable to mix a pre-dispersion liquid in which an inorganic filler is pre-dispersed in a solvent or a curable resin, and the surface-treated inorganic filler is pre-dispersed in a solvent and the pre-dispersion liquid is blended in the composition. Alternatively, it is more preferable to sufficiently surface-treat the surface-untreated inorganic filler when pre-dispersing it in the solvent, and then add the pre-dispersion liquid to the composition.

The inorganic filler (C) may be blended with an epoxy resin or the like in a powder or solid state, or may be mixed with a solvent or a dispersant to form a slurry and then blended with the epoxy resin or the like.

(C) The inorganic filler may be used alone or as a mixture of two or more. The blending amount of the inorganic filler (C) is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 65% by mass or more, when the non-volatile content in the curable resin composition is 100% by mass. Further, from the viewpoint of toughness of the cured film, 90% by mass or less is preferable, 80% by mass or less is more preferable, and 75% by mass or less is particularly preferable.

In the present specification, the non-volatile component in the curable resin composition means a component excluding the organic solvent.

[(D) Phenoxy resin]
The curable resin composition of the present invention further contains (D) a phenoxy resin from the viewpoint of improving the glass transition temperature while maintaining the dielectric loss tangent low and improving the mechanical strength of the obtained cured film.

The phenoxy resin (D) is a phenoxy resin which is a condensate of epichlorohydrin and various bifunctional phenol compounds, or a phenoxy resin obtained by esterifying the hydroxyl group of the hydroxy ether portion present in the skeleton of the phenoxy resin using various acid anhydrides or acid chlorides. And so on. Above all, it is preferable that the (D) phenoxy resin contains a phenoxy resin containing either or both of a biphenyl skeleton and a fluorene skeleton. By containing these skeletons, a cured product having a high glass transition temperature, a high peel strength, and a low dielectric loss tangent can be suitably obtained.

Specific examples of the (D) phenoxy resin include FX280S and FX293 manufactured by Nittetsu Chemical & Materials, jER (registered trademark) YX8100BH30, jER (registered trademark) YX6954BH30, and jER (registered trademark) YL6954 and jER manufactured by Mitsubishi Chemical Corporation. (Registered trademark) YL6974, jER (registered trademark) YX7200B35, jER (registered trademark) 1256B40 and the like can be mentioned.

Of these, the phenoxy resins containing either or both of the biphenyl skeleton and the fluorene skeleton are FX280S and FX293 manufactured by Nittetsu Chemical & Materials Co., Ltd., jER® YX8100BH30 manufactured by Mitsubishi Chemical Corporation, and jER®. YX6954BH30 and jER® YX7200B35. (D) The phenoxy resin may be used alone or in combination of two or more.

The blending amount of (D) phenoxy resin is obtained when the total of (A) epoxy resin and (B) compound having an active ester group in the curable resin composition is 100% by mass in terms of non-volatile content. From the viewpoint of the mechanical strength of the cured film, 1% by mass or more is preferable, and 5% by mass or more is more preferable. Further, from the viewpoint of the dielectric property of the cured film, 20% by mass or less is preferable, and 15% by mass or less is more preferable.

[Curing accelerator]
The curable resin composition of the present invention can contain a curing accelerator. The curing accelerator promotes a thermosetting reaction, and is used to further improve properties such as adhesion, chemical resistance, and heat resistance.

In the present invention, the curing accelerator can be used mainly for accelerating the reaction of (A) an epoxy resin and (B) a compound having an active ester group.

Specific examples of the curing accelerator for the curing reaction with (A) an epoxy resin and (B) a compound having an active ester group include imidazole and its derivatives; guanamines such as acetoguanamine and benzoguanamine; diaminodiphenylmethane and m-phenylene. Polyamines such as diamines, m-xylenediamines, diaminodiphenylsulphons, dicyandiamides, ureas, urea derivatives, melamines, polybasic hydrazides; these organic acid salts and / or epoxy adducts; amine complexes of boron trifluoride; ethyldiamino- Triazine derivatives such as S-triazine, 2,4-diamino-S-triazine, 2,4-diamino-6-xysilyl-S-triazine; trimethylamine, triethanolamine, N, N-dimethyloctylamine, N-benzyl Amines such as dimethylamine, pyridine, dimethylaminopyridine, N-methylmorpholin, hexa (N-methyl) melamine, 2,4,6-tris (dimethylaminophenol), tetramethylguanidine, m-aminophenol; polyvinylphenol Polyphenols such as polyvinylphenol bromide, phenol novolac, alkylphenol novolac; organic phosphines such as tributylphosphin, triphenylphosphine, tris-2-cyanoethylphosphine; tri-n-butyl (2,5-dihydroxyphenyl) phosphonium bromide , Hexadecyltributylphosphonium chloride and other phosphonium salts; benzyltrimethylammonium chloride, phenyltributylammonium chloride and other quaternary ammonium salts; the polybasic acid anhydride; diphenyliodonium tetrafluoroboroate, triphenylsulfonium hexafluoroantimonate, 2 , 4,6-Triphenylthiopyrilium hexafluorophosphate and other photocationic polymerization catalysts; styrene-maleic anhydride resin; equimolar reactants of phenylisocyanate and dimethylamine, and organic polyisocyanates such as tolylene diisocyanate and isophorone diisocyanate. Examples thereof include conventionally known curing accelerators such as an equimolar reaction product of dimethylamine and a metal catalyst. Among the curing accelerators, imidazole and its derivatives, dimethylaminopyridine, are preferable.

As the curing accelerator, one kind may be used alone or two or more kinds may be mixed. When the curing accelerator is blended in the curable resin composition of the present invention, the blending amount thereof is when the total amount of non-volatile components of (A) the epoxy resin and (B) the compound having an active ester group is 100% by mass. From the viewpoint of storage stability of the curable resin composition before the thermosetting reaction, 5% by mass or less is preferable, 3% by mass or less is more preferable, and from the viewpoint of curability, 0.01% by mass or more is preferable. , 0.1% by mass or more is more preferable.

[Organic solvent]
The curable resin composition of the present invention may contain an organic solvent for adjusting the curable resin composition or, in the case of producing a dry film, for coating on a carrier film described later. The organic solvent is not particularly limited, and examples thereof include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents and the like. can. More specifically, ketones such as methyl ethyl ketone, cyclohexanone, methyl butyl ketone and methyl isobutyl ketone; aromatic hydrocarbons such as toluene, xylene and tetramethyl benzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol and methyl carbitol. , Butyl carbitol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether and other glycol ethers; Esters such as ethyl acetate, butyl acetate, isobutyl acetate, ethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol butyl ether acetate; ethanol, propanol, 2- Alcohols such as methoxypropanol, n-butanol, isobutyl alcohol, isopentyl alcohol, ethylene glycol, propylene glycol; aliphatic hydrocarbons such as octane and decane; petroleum such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. In addition to system solvents and the like, N, N-dimethylformamide (DMF), tetrachloroethylene, televisionn oil and the like can be mentioned. In addition, Maruzen Petrochemical Co., Ltd. Swazole 1000, Swazole 1500, Sankyo Chemical Co., Ltd. Solvent # 100, Solvent # 150, Shell Chemicals Japan Co., Ltd. Shell Zol A100, Shell Zol A150, Idemitsu Kosan Co., Ltd. Ipsol No. 100, Ipsol No. 150, etc. You may use the organic solvent of. As the organic solvent, one kind may be used alone or two or more kinds may be used in combination.

When formed into a dry film, the amount of residual solvent in the resin layer is preferably 0.1 to 10.0% by mass. When the residual solvent is 10.0% by mass or less, bumping during heat curing is suppressed and the flatness of the surface becomes better. In addition, it is possible to prevent the resin from flowing due to the melt viscosity being lowered too much, and the flatness is improved. When the residual solvent is 0.1% by mass or more, particularly 0.5 or more, the fluidity at the time of laminating is good, and the flatness and the embedding property are better.

[Other ingredients]
The curable resin composition of the present invention further comprises, if necessary, polybutadiene rubber, polyisopropylene rubber, urethane-modified polybutadiene rubber, epoxy-modified polybutadiene rubber, acrylonitrile-modified polybutadiene rubber, carboxyl group-modified polybutadiene rubber, carboxyl group or hydroxyl group. Modified acrylonitrile butadiene rubber and its crosslinked rubber particles, rubber-like particles such as core-shell type rubber particles, hydrated metals such as aluminum hydroxide and magnesium hydroxide, red phosphorus, ammonium phosphate, ammonium carbonate, zinc borate, Flame retardants such as zinc tin, molybdenum compound, bromine compound, chlorine compound, phosphoric acid ester, phosphorus-containing polyol, phosphorus-containing amine, melamine cyanurate, melamine compound, triazine compound, guanidine compound, silicon polymer, silicon powder, Organic fillers such as fluorine powder and nylon powder, conventionally known colorants such as phthalocyanine blue, phthalocyanine green, iodin green, disazo yellow, crystal violet, titanium oxide, carbon black and naphthalene black, asbestos, olben, benton, Conventionally known thickeners such as fine powder silica, silicone-based, fluorine-based, polymer-based defoaming agents and / or leveling agents, thiazole-based, triazole-based, adhesion-imparting agents such as silane coupling agents, titanates. Conventionally known additives such as a system and an aluminum system can be used.

The curable resin composition of the present invention may be used as a dry film or may be used as a liquid. When used as a liquid, it may be one-component or two-component or more, but it is preferably two-component or more from the viewpoint of storage stability.

<Dry film>
The dry film of the present invention can be produced by applying the curable resin composition of the present invention on a carrier film and drying it to form a resin layer as a dry coating film. A protective film can be laminated on the resin layer, if necessary.

The carrier film has a role of supporting the resin layer of the dry film, and is a film to which the curable resin composition is applied when the resin layer is formed. Examples of the carrier film include polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyimide films, polyamideimide films, polyethylene films, polytetrafluoroethylene films, polypropylene films, and films made of thermoplastic resins such as polystyrene films, and Surface-treated paper or the like can be used. Among these, a polyester film can be preferably used from the viewpoints of heat resistance, mechanical strength, handleability and the like. The thickness of the carrier film is not particularly limited, but is appropriately selected depending on the intended use in the range of approximately 10 to 150 μm. The surface of the carrier film on which the resin layer is provided may be subjected to a mold release treatment. Further, spatter or copper foil may be formed on the surface of the carrier film on which the resin layer is provided.

The protective film is provided on the surface opposite to the carrier film of the resin layer for the purpose of preventing dust and the like from adhering to the surface of the resin layer of the dry film and improving handleability. As the protective film, for example, a film made of the thermoplastic resin exemplified in the carrier film, surface-treated paper and the like can be used, and among these, a polyester film, a polyethylene film and a polypropylene film are preferable. The thickness of the protective film is not particularly limited, but is appropriately selected depending on the application in the range of approximately 10 to 150 μm. The surface of the protective film on which the resin layer is provided may be subjected to a mold release treatment.

<Copper foil with resin>
The copper foil with a resin of the present invention has a resin layer obtained by applying the curable resin composition of the present invention to the copper foil surface of a copper foil or a copper foil with a carrier and drying it.

[Copper foil with carrier]
The copper foil with a carrier may have a structure in which the carrier foil and the copper foil are provided in this order, and the resin layer made of the curable resin composition of the present invention may be laminated so as to be in contact with the copper foil. It is preferable to use an ultrathin copper foil as the copper foil.

Examples of the carrier foil include copper foil, aluminum foil, stainless steel (SUS) foil, a resin film having a metal-coated surface, and the like, and copper foil is preferable. The copper foil may be an electrolytic copper foil or a rolled copper foil. The thickness of the carrier foil is usually 250 μm or less, preferably 9 to 200 μm. If necessary, a release layer may be formed between the carrier foil and the copper foil.

The method for forming the copper foil is not particularly limited, but an ultrathin copper foil is preferable, and a wet film forming method such as a non-electrolytic copper plating method and an electrolytic copper plating method, a dry film forming method such as sputtering and chemical vapor deposition, and a dry film forming method such as a sputtering method and a chemical vapor deposition method are used. , Can be formed by a combination of these. The thickness of the ultrathin copper foil is preferably 0.1 to 7.0 μm, more preferably 0.5 to 5.0 μm, and even more preferably 1.0 to 3.0 μm.

<Curing product>
The cured product of the present invention is obtained by curing the curable resin composition of the present invention, the resin layer of the dry film of the present invention, or the resin layer of the copper foil with resin of the present invention.

The method of curing is not particularly limited and may be cured by a conventionally known method, for example, it may be cured by heating at 150 to 230 ° C. As a method for manufacturing a printed wiring board using a curable resin composition, for example, in the case of a dry film having a three-layer structure in which a resin layer is sandwiched between a carrier film and a protective film, printing is performed by the following method. Wiring boards can be manufactured.

That is, either the carrier film or the protective film is peeled off from the dry film, heat-laminated on the circuit board on which the circuit pattern is formed, and then thermosetting. The thermosetting may be cured in an oven or may be cured by a hot plate press. When laminating or hot plate pressing the circuit board and the dry film of the present invention, the copper foil or the circuit board can be laminated at the same time. A printed wiring board can be manufactured by forming a pattern or via hole on a circuit board at a position corresponding to a predetermined position by laser irradiation or a drill to expose the circuit wiring. At this time, if there is a residual component (smear) that cannot be completely removed on the pattern or the circuit wiring in the via hole, the desmear process is performed. The remaining carrier film or protective film may be peeled off either after laminating, after thermosetting, after laser processing, or after desmear treatment.

Further, when the printed wiring board is manufactured using the copper foil with resin of the present invention, the resin layer is laminated on the circuit board, and the copper foil is used as all or part of the wiring layer by the modified semi-additive process (MSAP) method. Circuits may be formed and build-up wiring boards may be manufactured. Further, a build-up wiring board in which a circuit is formed by a semi-additive process (SAP) method may be manufactured by removing the copper foil. Further, the printed wiring board may be manufactured by a direct build-up on wafer in which the copper foil with resin is laminated and the circuit is formed alternately on the semiconductor integrated circuit. Further, a coreless build-up method in which resin layers and conductor layers are alternately laminated may be used without using a core substrate.

<Electronic components>
The electronic component of the present invention has a cured product of the present invention, that is, a cured resin composition of the present invention, a resin layer of a dry film of the present invention, or a cured product of a resin layer of a copper foil with a resin of the present invention.

Examples of the electronic component include a permanent protective film of a printed wiring board, and among them, a solder resist layer, an interlayer insulating layer, and a coverlay of a flexible printed wiring board. In addition, electronic components include applications other than printed wiring boards, for example, passive components such as inductors.

The curable resin composition of the present invention can be suitably used for filling permanent holes in printed wiring boards, for example, for filling holes such as through holes and via holes, in addition to the above-mentioned uses. It can also be used as a sealing material for semiconductor chips, as a material for copper-clad laminates (CCL) and prepregs.

Further, since the cured product of the curable resin composition of the present invention has excellent dielectric properties, it is considered that the transmission quality is good even in high frequency applications by using the cured product. Specific examples of high-frequency applications include millimeter-wave radars for automatic operation, millimeter-wave sensor boards, high-speed communication-compatible mobile motherboards, and SLPs (Substrate-Like PCBs) that form circuits using the modified semi-additive process (MSAP) method. ), Application processors (APs) for mobile and personal computers, high-frequency boards for base station servers and routers, boards for antennas, semiconductor encapsulation materials, and the like.

Further, the wiring board may be formed by bonding the wirings using the dry film of the present invention.

The form of the circuit forming material using the curable resin composition of the present invention is compatible with modified semi-additive process (MSAP) -compatible copper foil with resin (RCC: Resin-Coated-Copper) and semi-additive process (SAP). It may be a build-up film.

The dielectric loss tangent of the cured product of the present invention is not particularly limited, but according to the present invention, a cured product having a low dielectric loss tangent can be obtained. It can be 0.002 or less, and even 0.001 or less.

The present invention is not limited to the configuration and examples of the above-described embodiment, and various modifications can be made within the scope of the gist of the invention.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. In the following, unless otherwise specified, "parts" shall mean parts by mass.

((A1) Synthesis of biphenyl tetrafunctional epoxy resin represented by the general formula (1))
[Synthesis Example 1]
First, 26.63 g (0.1 mol) of biphenyl 4,4'-diallyl ether dissolved in 27 ml of toluene, 0.11 g of sodium carbonate and 0.43 g of LiCl are added to a 50 ml circle equipped with a cooler, a thermometer and a stirrer. It was introduced into a bottom flask and heated to 188-192 ° C. to distill off toluene. After reacting for 2 hours, the reaction mixture was cooled, absorbed in chloroform and washed with water. The organic phase was dried and concentrated to isolate 20.50 g (77%) of 3,3'-diallyl-4,4'-dihydroxybiphenyl, an intermediate of (A1).

Next, 70.00 g of 3,3'-diallyl biphenyl 4,4'-diglycidyl ether (intermediate of (A1) above, 0.185 mol) and 2.99 g of sodium acetate in 20 ml of chloroform are stirred and cooled. It was introduced into a 350 ml sulfonated flask equipped with a vessel, a thermometer and a dropping wax, and 80.56 g (0.39 mol) of 40% peracetic acid was added dropwise at room temperature over about 2 hours. After completion of the dropwise addition, the reaction mixture is stirred for an additional 3 hours, then 200 ml of chloroform is added, washed several times with water until the organic phase is neutral, dried with Na ₂ SO ₄ , filtered and evacuated. And concentrated. As a result, the epoxide content is 8,230 equivalents / kg (84.47% of the theoretical value) and the viscosity is 280 mPas / 80 ° C. 3,3'-diglycidyl biphenyl 4,4'-diglycidyl ether 70.45 g ( 92.77% of the theoretical value) was obtained.

((B) Synthesis of compound having active ester group)
[Synthesis Example 1 (Synthesis of (B-1))]
203.0 g of isophthalic acid chloride (number of moles of acid chloride group: 2.0 mol) and 1338 g of toluene were charged in a flask equipped with a thermometer, a dropping funnel, a cooling tube, a fractionation tube, and a stirrer, and the inside of the system was replaced with nitrogen under reduced pressure. And dissolved. Next, 96.0 g (0.67 mol) of α-naphthol and 220 g of dicyclopentadienephenol resin (number of moles of phenolic hydroxyl group: 1.33 mol) were charged, and the inside of the system was replaced with nitrogen under reduced pressure to dissolve it. Then, 1.12 g of tetrabutylammonium bromide was dissolved, and the inside of the system was controlled to 60 ° C. or lower while purging with nitrogen gas, and 400 g of a 20% sodium hydroxide aqueous solution was added dropwise over 3 hours. Then, stirring was continued for 1.0 hour under this condition. After completion of the reaction, the liquid was statically separated and the aqueous layer was removed. Further, water was added to the toluene phase in which the reaction product was dissolved, and the mixture was stirred and mixed for about 15 minutes, and the solution was allowed to stand and separated to remove the aqueous layer. This operation was repeated until the pH of the aqueous layer reached 7. Then, water was removed by decanter dehydration to obtain an active ester resin (B-1) in a toluene solution with a non-volatile content of 65%.

The ester group equivalent in terms of solid content of the obtained active ester resin (B-1) was 223 g / mol.

[Synthesis Example 2 (Synthesis of (B-2)))]
First, in a flask equipped with a thermometer, a dropping funnel, a cooling tube, a fractionation tube, and a stirrer, 320 g (2.0 mol) of 2,7-dihydroxynaphthalene, 184 g (1.7 mol) of benzyl alcohol, and paratoluenesulfone. 5.0 g of acid / monohydrate was charged, and the mixture was stirred at room temperature while blowing nitrogen. Then, the temperature was raised to 150 ° C., and the generated water was stirred for 4 hours while being distilled off from the system. After completion of the reaction, 900 g of methyl isobutyl ketone and 5.4 g of a 20% aqueous sodium hydroxide solution were added for neutralization, the aqueous layer was removed by liquid separation, and the mixture was washed with 280 g of water three times to reduce the pressure of methyl isobutyl ketone. The bottom was removed to obtain 460 g of a benzyl-modified naphthalene compound (B-2 intermediate). The obtained benzyl-modified naphthalene compound (B-2 intermediate) was a black solid, and the hydroxyl group equivalent was 180 g / equivalent.

Next, 203.0 g of isophthalic acid chloride (number of moles of acid chloride group: 2.0 mol) and 1400 g of toluene were charged in a flask equipped with a thermometer, a dropping funnel, a cooling tube, a fractionation tube, and a stirrer. The inside was replaced with reduced pressure nitrogen to dissolve it. Next, 96.0 g (0.67 mol) of α-naphthol and 240 g (molar number of phenolic hydroxyl groups: 1.33 mol) of the benzyl-modified naphthalene compound (B-2 intermediate) were charged, and the inside of the system was replaced with nitrogen under reduced pressure. Dissolved. Then, 0.70 g of tetrabutylammonium bromide was dissolved, and the inside of the system was controlled to 60 ° C. or lower while purging with nitrogen gas, and 400 g of a 20% sodium hydroxide aqueous solution was added dropwise over 3 hours. Then, stirring was continued for 1.0 hour under this condition. After completion of the reaction, the liquid was statically separated and the aqueous layer was removed. Further, water was added to the toluene layer in which the reaction product was dissolved, and the mixture was stirred and mixed for 15 minutes, and the solution was allowed to stand and separated to remove the aqueous layer. This operation was repeated until the pH of the aqueous layer reached 7. Then, water was removed by decanter dehydration to obtain an active ester resin (B-2) in a toluene solution state having a non-volatile content of 65% by mass. The ester group equivalent in terms of solid content of the obtained active ester resin (B-2) was 230 g / mol.

<1. Preparation of curable resin composition>
The various components shown in Table 1 below are kneaded and mixed at the ratio shown in the same table (mass part in terms of non-volatile content), and the curable resins of Examples 1 to 11 and Comparative Examples 1 to 3 for producing a film after curing are obtained. The composition was adjusted. The numerical values in Table 1 indicate the parts by mass or the mass% in terms of non-volatile content.

For each of the curable resin compositions, test samples were prepared as shown below, and the glass transition temperature (Tg), dielectric loss tangent, peel strength and room temperature elastic modulus were evaluated. The results are shown in Table 1.

<2. Creating a film after curing>
Using a film applicator, the curable resin compositions of the above-mentioned Examples and Comparative Examples were applied onto the glossy surface of a copper foil (F2-WS manufactured by Furukawa Electric Co., Ltd., 18 μm thickness), and a hot air circulation type was applied. After drying in a drying oven at 90 ° C. for 10 minutes and then curing at 200 ° C. for 60 minutes, the copper foil was peeled off to prepare a cured film (cured film) having a thickness of about 40 μm.

<3. Measurement of glass transition temperature (Tg)>
The above <2. Preparation of film after curing> The sample obtained was cut out to a measurement size (size of 3 mm × 10 mm), and the glass transition temperature (Tg) was measured using TMA Q400EM manufactured by TA Instruments. The temperature was raised above room temperature at a heating rate of 10 ° C./min, and measurements were taken twice in succession, and the glass transition temperature (Tg), which is the intersection of two tangents having different linear thermal expansion coefficients, was evaluated.

The glass transition temperature was evaluated according to the following criteria.

⊚: 180 ° C or higher ○: less than 180 ° C 175 ° C or higher ×: less than 175 ° C

<4. Measurement of dielectric loss tangent (10 GHz)>
The above <2. Preparation of cured film> Cut out the sample obtained in measurement size (size of 50 mm x 60 mm), and measure the dielectric loss tangent at 23 ° C using an SPDR dielectric resonator and a network analyzer (both manufactured by Agilent). Was done.

The evaluation of the dielectric loss tangent (10 GHz) was performed according to the following criteria.

⊚: less than 0.003 ○: 0.003 or more and less than 0.010 ×: 0.010 or more

<5. Evaluation of peel strength ＞
<Preparation of sample for peel strength measurement>
(1) Roughening treatment of laminated board Both sides of the glass cloth base material epoxy resin double-sided copper-clad laminated board [copper foil thickness 18 μm, substrate thickness 0.3 mm, Panasonic R5715ES] on which the inner layer circuit is formed are manufactured by MEC. The copper surface was roughened (etching amount: about 1 μm) by immersing it in the CZ8100 manufactured by Japan.

(2) Preparation of Copper Foil with Resin Using a film applicator, a curable resin composition was applied to each Example and Comparative Example of ultra-thin copper foil with a carrier (MT18Ex manufactured by Mitsui Kinzoku Co., Ltd., ultra-thin copper 3 μm thick). It was applied onto the thin copper foil surface and dried in a hot air circulation type drying furnace at 90 ° C. for 10 minutes to obtain a resin-coated copper foil having a resin layer thickness of about 40 μm.

(3) Laminating of copper foil with resin Using a batch type vacuum pressurizing laminator MVLP-500 (manufactured by Meiki Co., Ltd.), copper foil with resin (2) was used on both sides of the laminated board subjected to the roughening treatment (1). ) Resin composition coated surface was laminated. Lamination was performed by reducing the pressure for 30 seconds to a pressure of 13 hPa or less, and then pressing at 80 ° C. and a pressure of 0.5 MPa for 30 seconds.

(4) Curing of Resin Composition The laminated board (3) laminated with the copper foil with resin was cured at 170 ° C. for 30 minutes in a hot air circulation type drying oven.

(5) Electrolytic copper plating After curing, the carrier copper foil was peeled off from both sides of the laminated plate, and the ultrathin copper foil (3 μm) on both sides was made about 25 μm thick by electrolytic copper plating.

(6) Annealing Treatment The laminated plate after electrolytic copper plating was annealed at 200 ° C. for 60 minutes in a hot air circulation type drying oven.

<Measurement of peel strength>
Using the sample prepared by the above method, it was measured according to JIS C6481 and evaluated according to the following criteria. The results are shown in Table 1.

⊚: Peel strength 0.7 kN / m or more ○: Peel strength 0.3 kN / m or more and less than 0.7 kN / m ×: Peel strength less than 0.3 kN / m

<6. Evaluation of normal temperature elastic modulus>
The above <2. Preparation of film after curing> Cut out the sample obtained in the measurement size (size of 5 mm x 100 mm), and use the small desktop tester EZ-SX manufactured by Shimadzu Corporation to set the initial chuck interval to 50 mm and the tensile speed 1. A tensile test was carried out under the conditions of 0 mm / min and 23 ° C., and the normal temperature elastic modulus was measured and evaluated according to the following criteria.

◯: 10 GPa or more Δ: less than 10 GPa 9 GPa or more ×: less than 9 GPa

* 1: 3,3'-diglycidyl biphenyl 4,4'-diglycidyl ether (manufactured by synthetic example 1 of synthesis of biphenyl tetrafunctional epoxy resin represented by (A1) general formula (1))
* 2: Mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin, liquid, epoxy equivalent: 165 g / eq (EPICLON (registered trademark) EXA-835LV, manufactured by DIC Corporation)
* 3: Biphenyl novolac type epoxy resin, solid, epoxy equivalent: 290 g / eq (NC-3000H, manufactured by Nippon Kayaku Co., Ltd., epoxy resin represented by the general formula (6))
* 4: NC-3500 (manufactured by Nippon Kayaku Co., Ltd., biphenyl novolac type epoxy resin, epoxy equivalent: 290 g / eq, epoxy resin represented by the general formula (6))
* 5: ESN-475V (manufactured by Nittetsu Chemical & Materials Co., Ltd., naphthalene aralkyl type epoxy resin, epoxy equivalent: 330 g / eq, epoxy resin represented by the general formula (6))
* 6: Produced by (B) Synthesis Example 1 (Synthesis of (B-1)) of synthesis of a compound having an active ester group (active ester equivalent: 223 g / eq).
* 7: Produced by (B) Synthesis Example 2 (Synthesis of (B-2)) for the synthesis of a compound having an active ester group (active ester equivalent: 230 g / eq).
* 8: Phenol novolak (TD-2090, manufactured by DIC Corporation)
* 9: Spherical silica treated with phenylaminosilane, average particle size: 0.5 μm, carbon content per unit mass 0.18 (SO-C2, manufactured by Admatex)
* 10: Phenoxy resin containing biphenyl skeleton and bisphenol acetophenone skeleton (YX6954BH30, manufactured by Mitsubishi Chemical Corporation)
* 11: Phenoxy resin containing a biphenyl skeleton and a skeleton derived from 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (YX7200BH35, manufactured by Mitsubishi Chemical Corporation).
* 12: Phenoxy resin containing biphenyl skeleton and bisphenol S skeleton (YX8100BH30, manufactured by Mitsubishi Chemical Corporation)
* 13: Bisphenol fluorenone type phenoxy resin (FX293, manufactured by Nittetsu Chemical & Materials Co., Ltd.)
* 14: Bisphenol A type phenoxy resin (both biphenyl skeleton and bisphenol fluorenone skeleton are not included)
* 15: 2-Ethyl-4-methylimidazole

From the comparison between Examples 1 to 13 and Comparative Examples 1 to 3 in Table 1, (A) a biphenyl tetrafunctional epoxy resin represented by the general formula (1) as an epoxy resin, and (B) an active ester. A cured product of a curable resin composition containing a compound having a group, (C) an inorganic filler and (D) a phenoxy resin is higher in glass than a cured product of a curable resin composition lacking even one of these components. It has the characteristics of transition temperature, small dielectric tangent, high peel strength and high room temperature elasticity.

Further, as can be seen from the comparison of Examples 13, 9, 11 and 5, biphenyl represented by (A1) general formula (1) with respect to the total amount of (A) epoxy resin and (B) compound having an active ester group. It was found that the peel strength increased as the blending ratio of the tetrafunctional epoxy resin decreased in the order of Example 13, Example 9, Example 11, and Example 5.

Claims (10)

(A) Epoxy resin,
(B) A compound having an active ester group,
A curable resin composition containing (C) an inorganic filler and (D) a phenoxy resin.
The (A) epoxy resin is the (A1) general formula (1).

(In the general formula (1), R ¹ and R ² independently represent a methyl group, a methoxy group or a halogen atom, and m and n independently represent an integer of 0 to 3). A curable resin composition comprising a biphenyl tetrafunctional epoxy resin. The first aspect of claim 1, wherein the ratio of the total amount of epoxy groups in the (A) epoxy resin to the total amount of ester groups in the compound having the (B) active ester group is 0.2 or more and 0.6 or less. Curable resin composition. The blending ratio of the biphenyl tetrafunctional epoxy resin represented by the general formula (1) to the total amount of the (A) epoxy resin and (B) the compound having an active ester group is 3.0 mass in terms of non-volatile content. The curable resin composition according to claim 1 or 2, wherein the content is in the range of% or more and 15.0% by mass or less. The curable resin according to any one of claims 1 to 3, wherein the (D) phenoxy resin contains (D1) a biphenyl skeleton-containing phenoxy resin and / or (D2) a fluorene-type skeleton-containing phenoxy resin. Composition. (B) The compound having an active ester group has the following general formula (2).

(In formula (2), X ₁ is a group independently having a benzene ring or a naphthalene ring, k represents 0 or 1, and n is an average of 0.25 to 1.5 in repeating units.) The curable resin composition according to any one of claims 1 to 4, which is a compound represented by. (B) The compound having an active ester group has the following general formula (3):

(In the formula (3), X ₂ is independently the following formula (4):

Group represented by or the following formula (5):

It is a group represented by
m is an integer of 1 to 6, n is an integer of 1 to 5 independently, and q is an integer of 1 to 6 independently.
In equation (4), k is an integer of 1 to 5 independently.
In the formula (5), Y is a group represented by the above formula (4) (k is an integer of 1 to 5 independently), and t is an integer of 0 to 5 independently).
The curable resin composition according to any one of claims 1 to 4, which is a compound having a structural portion represented by and having a structure in which both ends thereof are monovalent aryloxy groups. A dry film comprising the curable resin composition according to any one of claims 1 to 6 as a resin layer. A copper foil with a resin, which comprises the curable resin composition according to any one of claims 1 to 6 as a resin layer on the copper foil or the copper foil with a carrier. The curable resin composition according to any one of claims 1 to 6, the resin layer of the dry film according to claim 7, or the cured product of the resin layer of the copper foil with resin according to claim 8. An electronic component comprising the cured product according to claim 9.