KR20200135761A - Curable resin composition, adhesive, adhesive film, coverlay film and flexible copper clad laminate - Google Patents

Abstract

An object of the present invention is to provide a curable resin composition capable of obtaining a cured product excellent in high temperature long-term heat resistance, moisture absorption reflow resistance, and plating resistance. In addition, the present invention aims to provide an adhesive comprising the curable resin composition, an adhesive film formed using the curable resin composition, and a coverlay film having a cured product of the curable resin composition and a flexible copper clad laminate To do.
The present invention is a curable resin composition containing a curable resin, an imide skeleton in a main chain, an imide oligomer having a crosslinkable functional group in a terminal, and an ion trapping agent.

Description

Curable resin composition, adhesive, adhesive film, coverlay film and flexible copper clad laminate

The present invention relates to a curable resin composition capable of obtaining a cured product excellent in high temperature long-term heat resistance, moisture absorption reflow resistance, and plating resistance. In addition, the present invention relates to an adhesive containing the curable resin composition, an adhesive film formed using the curable resin composition, and a coverlay film having a cured product of the curable resin composition, and a flexible copper clad laminate.

Curable resins such as epoxy resins that have low shrinkage and are excellent in adhesiveness, insulation and chemical resistance are used in many industrial products. In particular, in the use of electronic devices, a curable resin composition in which good results are obtained in a solder reflow test for a short time heat resistance or a cold heat cycle test for a repeated heat resistance is widely used.

In recent years, automotive electrical control units (ECUs) and power devices using SiC and GaN have attracted attention, but the curable resin compositions used in these applications have been exposed to high temperatures continuously for a long period of time, rather than short time or repeated heat resistance. The heat resistance (high temperature long-term heat resistance) of the time is obtained.

As a curing agent used in a curable resin composition, for example, Patent Document 1 discloses a polyimide obtained by reacting an acid anhydride component composed of an aromatic tetracarboxylic dianhydride and a diamine component composed of an aromatic diamine. In Patent Document 1, by using the polyimide, it is possible to form an adhesive layer that does not lower the adhesive strength between the wiring layer and the coverlay film even in a use environment exposed to repeated high temperatures. However, in the conventional curable resin composition using such a polyimide, it is difficult to maintain the adhesive force under a more severe temperature environment. Moreover, a curable resin composition having an excellent effect also in moisture absorption reflow resistance has been demanded.

Japanese Patent Application Publication No. 2017-145344

An object of the present invention is to provide a curable resin composition capable of obtaining a cured product excellent in high temperature long-term heat resistance, moisture absorption reflow resistance, and plating resistance. In addition, the present invention aims to provide an adhesive comprising the curable resin composition, an adhesive film formed using the curable resin composition, and a coverlay film having a cured product of the curable resin composition and a flexible copper clad laminate To do.

The present invention is a curable resin composition containing a curable resin, an imide skeleton in a main chain, an imide oligomer having a crosslinkable functional group in a terminal, and an ion scavenger.

The present invention is described in detail below.

The inventors of the present invention believe that the reason why the conventional curable resin composition is inferior in high-temperature long-term heat resistance or moisture absorption reflow resistance in a strict temperature environment is a source of curable resin composition, chloride ions derived from the cleaning solution of copper foil used for printed wiring boards, etc. I thought it was in a specific ion such as.

Therefore, the present inventors found that a cured product having excellent high-temperature long-term heat resistance and moisture absorption reflow resistance can be obtained by adding an ion scavenger to a curable resin composition containing a curable resin and an imide oligomer having a specific structure. And came to complete the present invention.

Further, the curable resin composition of the present invention is also excellent in initial adhesiveness and plating resistance.

The curable resin composition of the present invention contains an ion scavenger.

By containing the above ion scavenger, the curable resin composition of the present invention has a cured product excellent in high temperature long-term heat resistance and moisture absorption reflow resistance.

In addition, in this specification, the "ion scavenger" means an organic compound or inorganic compound having a function of adsorbing, trapping, or exchanging ions.

It is preferable that the said ion scavenger is an ion exchanger.

Examples of the ion exchanger include zirconium compounds, antimony compounds, magnesium aluminum compounds, antimony bismuth compounds, zirconium bismuth compounds, and the like. Among them, an anion exchanger or a positive ion exchanger is preferable, an anion exchanger is more preferable, and an anion exchanger magnesium aluminum-based compound is still more preferable.

The ion scavenger may be used alone, or two or more types may be used in combination.

It is preferable that the said ion scavenger is a particle of 10 micrometers or less in average particle diameter from a viewpoint of ion trapping ability. When the ion scavenger is particles having an average particle diameter of 10 µm or less, the cured product of the resulting curable resin composition is more excellent in high temperature long-term heat resistance and moisture absorption reflow resistance. The ion scavenger is more preferably particles having an average particle diameter of 6 µm or less, and still more preferably particles having an average particle diameter of 2 µm or less.

In addition, there is no particular lower limit of the average particle diameter of the ion scavenger, but from the viewpoint of thickening and the like, the ion scavenger is preferably a particle having an average particle diameter of 0.01 µm or more, and more preferably 0.1 µm or more.

In addition, the average particle diameter of the ion scavenger, and the inorganic filler and flow regulator described later can be measured by dispersing the particles in a solvent (water, organic solvent, etc.) using NICOMP 380ZLS (manufactured by PARTICLE SIZING SYSTEMS). have.

The content of the ion scavenger is a preferable lower limit of 0.1 parts by weight and a preferable upper limit of 200 parts by weight per 100 parts by weight of the total of the curable resin and the imide oligomer. When the content of the ion scavenger is within this range, the cured product of the resulting curable resin composition is more excellent in high temperature long-term heat resistance and moisture absorption reflow resistance. A more preferable lower limit of the content of the ion scavenger is 1 part by weight, a more preferable upper limit is 50 parts by weight, and a further preferable upper limit is 20 parts by weight.

The curable resin composition of the present invention contains an imide oligomer having an imide skeleton in the main chain and a crosslinkable functional group at the terminal (hereinafter, also referred to as "imide oligomer according to the present invention"). The imide oligomer according to the present invention is excellent in reactivity and compatibility with a curable resin such as an epoxy resin. The curable resin composition of the present invention contains the imide oligomer according to the present invention, so that the cured product is excellent in mechanical strength at high temperature and long-term heat resistance at high temperature.

It is preferable that the said crosslinkable functional group is a functional group which can react with an epoxy group.

Specific examples of the crosslinkable functional group include an amino group, a carboxyl group, an acid anhydride group, a phenolic hydroxyl group, an unsaturated group, an active ester group, and a maleimide group. Among them, at least any one of an acid anhydride group and a phenolic hydroxyl group is more preferable. The imide oligomer according to the present invention may have the crosslinkable functional group at one end or at both ends. In the case of having the crosslinkable functional groups at both ends, the curable resin composition obtained by increasing the crosslinking density will have a higher glass transition temperature after curing. On the other hand, in the case of having the crosslinkable functional group at one end, the functional group equivalent is increased, and the content of the imide oligomer according to the present invention in the curable resin composition can be increased, so that the cured product of the resulting curable resin composition has more high-temperature long-term heat resistance. It becomes excellent.

It is preferable that the imide oligomer according to the present invention has a structure represented by the following formula (1-1) or the following formula (1-2) as a structure containing the crosslinkable functional group. By having a structure represented by the following formula (1-1) or the following formula (1-2), the imide oligomer according to the present invention is more excellent in reactivity and compatibility with a curable resin such as an epoxy resin.

[Formula 1]

In formula (1-1) and formula (1-2), A is a tetravalent group represented by following formula (2-1) or following formula (2-2), and in formula (1-1), B is , It is a divalent group represented by the following formula (3-1) or the following formula (3-2), and in formula (1-2), Ar is a divalent aromatic group which may be substituted.

[Formula 2]

In formulas (2-1) and (2-2), * is a bonding position, and in formula (2-1), Z is a bonding hand, an oxygen atom, or may be substituted, and an oxygen atom at the bonding position It is a divalent hydrocarbon group which may have. The hydrogen atom of the aromatic ring in formula (2-1) and formula (2-2) may be substituted.

[Formula 3]

In formulas (3-1) and (3-2), * is a bonding position, and in formula (3-1), Y is a bonding hand, an oxygen atom, or an optionally substituted divalent hydrocarbon group. The hydrogen atom of the aromatic ring in formula (3-1) and formula (3-2) may be substituted.

In addition, the imide oligomer according to the present invention is preferably an imide oligomer having no siloxane skeleton in its structure, since it may lower the glass transition temperature after curing or contaminate the adherend and cause poor adhesion. Do.

The preferred upper limit of the number average molecular weight of the imide oligomer according to the present invention is 4000. When the number average molecular weight is 4000 or less, the cured product of the resulting curable resin composition is more excellent in high temperature long-term heat resistance. A more preferable upper limit of the number average molecular weight of the imide oligomer according to the present invention is 3400, and a more preferable upper limit is 2800.

In particular, the number average molecular weight of the imide oligomer according to the present invention is preferably 900 or more and 4000 or less when it has a structure represented by the formula (1-1), and when it has a structure represented by the formula (1-2). It is preferably 550 or more and 4000 or less. In the case of having a structure represented by the above formula (1-1), a more preferable lower limit of the number average molecular weight is 950, and a more preferable lower limit is 1000. In the case of having a structure represented by the above formula (1-2), a more preferable lower limit of the number average molecular weight is 580, and a more preferable lower limit is 600.

In addition, in this specification, the said "number average molecular weight" is a value calculated|required by the conversion of polystyrene by performing measurement using tetrahydrofuran as a solvent by gel permeation chromatography (GPC). As a column used when measuring the number average molecular weight in terms of polystyrene by GPC, JAIGEL-2H-A (manufactured by Nippon Analytical Industry Co., Ltd.), etc. are mentioned, for example.

The imide oligomer according to the present invention is specifically an imide represented by the following formula (4-1), the following formula (4-2), the following formula (4-3), or the following formula (4-4) It is preferable that it is an oligomer or an imide oligomer represented by following formula (5-1), following formula (5-2), following formula (5-3), or following formula (5-4).

[Formula 4]

In formulas (4-1) to (4-4), A is a tetravalent group represented by the following formula (6-1) or the following formula (6-2), and the formulas (4-1) and (4- In 3) and formula (4-4), A may each be the same or different. In formulas (4-1) to (4-4), B is a divalent group represented by the following formula (7-1) or the following formula (7-2), and formulas (4-3) and (4- In 4), B may be the same or different, respectively. In formula (4-2), X is a hydrogen atom, a halogen atom, or a monovalent hydrocarbon group which may be substituted, and in formula (4-4), W is a hydrogen atom, a halogen atom, or may be substituted. It is a monovalent hydrocarbon group.

[Formula 5]

In formulas (5-1) to (5-4), A is a tetravalent group represented by the following formula (6-1) or the following formula (6-2), and the formula (5-3) and formula (5- In 4), A may be the same or different, respectively. In formulas (5-1) to (5-4), R is a hydrogen atom, a halogen atom, or an optionally substituted monovalent hydrocarbon group, and in formulas (5-1) and (5-3), R Silver may be the same or different, respectively. In formulas (5-2) and (5-4), W is a hydrogen atom, a halogen atom, or a monovalent hydrocarbon group which may be substituted, and in formulas (5-3) and (5-4), B is a divalent group represented by the following formula (7-1) or the following formula (7-2).

[Formula 6]

In formulas (6-1) and (6-2), * is a bonding position, and in formula (6-1), Z is a bonding hand, an oxygen atom, or may be substituted, and an oxygen atom at the bonding position It is a divalent hydrocarbon group which may have. The hydrogen atom of the aromatic ring in formula (6-1) and formula (6-2) may be substituted.

[Formula 7]

In formulas (7-1) and (7-2), * is a bonding position, and in formula (7-1), Y is a bonding hand, an oxygen atom, or an optionally substituted divalent hydrocarbon group. The hydrogen atom of the aromatic ring in formula (7-1) and formula (7-2) may be substituted.

Among the imide oligomers according to the present invention, as a method for producing an imide oligomer having a structure represented by the above formula (1-1), for example, an acid dianhydride represented by the following formula (8) and the following formula (9) The method of making the diamine represented by) react, etc. are mentioned.

[Formula 8]

In formula (8), A is a tetravalent group similar to A in said formula (1-1).

[Formula 9]

In formula (9), B is a divalent group similar to that of B in the formula (1-1), and R ¹ to R ⁴ are each independently a hydrogen atom or a monovalent hydrocarbon group.

A specific example of the method of making the acid dianhydride represented by said formula (8) and the diamine represented by said formula (9) react is shown below.

First, the diamine represented by the above formula (9) is previously dissolved in a solvent in which an amic acid oligomer obtained by the reaction is soluble (for example, N-methylpyrrolidone, etc.), and the obtained solution is represented by the formula (8). The indicated acid dianhydride is added and reacted to obtain an amic acid oligomer solution. Subsequently, the solvent is removed by heating or reduced pressure, and further, a method of reacting the amic acid oligomer by heating at about 200° C. or higher for 1 hour or more may be mentioned. By adjusting the molar ratio of the acid dianhydride represented by the formula (8) and the diamine represented by the formula (9) and the imidation conditions, the structure represented by the formula (1-1) has a desired number average molecular weight, and at both ends An imide oligomer having can be obtained.

Further, by substituting a part of the acid dianhydride represented by the formula (8) with an acid anhydride represented by the following formula (10), the structure represented by the formula (1-1) has a desired number average molecular weight, and at one end The imide oligomer having a structure derived from an acid anhydride represented by the following formula (10) at the other terminal can be obtained. In this case, the acid dianhydride represented by the formula (8) and the acid anhydride represented by the following formula (10) may be added at the same time or may be added separately.

Further, by substituting a part of the diamine represented by the formula (9) with a monoamine represented by the following formula (11), it has a desired number average molecular weight, and has a structure represented by the formula (1-1) at one terminal, An imide oligomer having a structure derived from a monoamine represented by the following formula (11) at the other terminal can be obtained. In this case, the diamine represented by the above formula (9) and the monoamine represented by the following formula (11) may be added at the same time or may be added separately.

[Formula 10]

In formula (10), Ar is a divalent aromatic group which may be substituted.

[Formula 11]

In formula (11), Ar is a monovalent aromatic group which may be substituted, and R ⁵ and R ⁶ are each independently a hydrogen atom or a monovalent hydrocarbon group.

Among the imide oligomers according to the present invention, as a method for producing an imide oligomer having a structure represented by the formula (1-2), for example, an acid dianhydride represented by the formula (8) and the following formula (12) The method of making the phenolic hydroxyl group-containing monoamine represented by) react, etc. are mentioned.

[Formula 12]

In formula (12), Ar is a divalent aromatic group which may be substituted, and R ⁷ and R ⁸ are each independently a hydrogen atom or a monovalent hydrocarbon group.

A specific example of a method of reacting an acid dianhydride represented by the formula (8) with a phenolic hydroxyl group-containing monoamine represented by the formula (12) is shown below.

First, a phenolic hydroxyl group-containing monoamine represented by formula (12) is previously dissolved in a solvent in which the amic acid oligomer obtained by the reaction is soluble (for example, N-methylpyrrolidone, etc.), and the above formula The acid dianhydride represented by (8) is added and reacted to obtain an amic acid oligomer solution. Subsequently, the solvent is removed by heating or reduced pressure, and further, a method of reacting the amic acid oligomer by heating at about 200° C. or higher for 1 hour or more may be mentioned. By adjusting the molar ratio of the acid dianhydride represented by the above formula (8) and the phenolic hydroxyl group-containing monoamine represented by the above formula (12) and the imidization conditions, it has a desired number average molecular weight, and the above formula (1-2) An imide oligomer having a structure represented by) can be obtained.

In addition, by substituting a part of the phenolic hydroxyl group-containing monoamine represented by the above formula (12) with the monoamine represented by the above formula (11), it has a desired number average molecular weight, and one terminal is represented by the above formula (1-2). An imide oligomer having a structure shown and having a structure derived from a monoamine represented by the formula (11) at the other terminal can be obtained. In this case, the phenolic hydroxyl group-containing monoamine represented by the formula (12) and the monoamine represented by the formula (11) may be added at the same time or may be added separately.

Examples of the acid dianhydride represented by the above formula (8) include pyromellitic dianhydride, 3,3'-oxydiphthalic dianhydride, 3,4'-oxydiphthalic dianhydride, and 4,4'- Oxydiphthalic dianhydride, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, 4,4'-bis(2,3-dicarboxylphenoxy)diphenylether dianhydride , p-phenylenebis (trimellitate anhydride), 2,3,3',4'-biphenyltetracarboxylic dianhydride, etc. are mentioned.

Among them, the acid dianhydride used for the raw material of the imide oligomer according to the present invention is preferably an aromatic acid dianhydride having a melting point of 240° C. or less, and a melting point of 220° C. Aromatic acid dianhydrides of the following are more preferable, aromatic acid dianhydrides having a melting point of 200° C. or less are more preferable, and 3,4′-oxydiphthalic dianhydride (melting point 180° C.), 4,4′-(4, Particularly preferred is 4'-isopropylidenediphenoxy)diphthalic anhydride (melting point 190°C).

In addition, in this specification, the "melting point" means a value measured as the temperature of the endothermic peak when the temperature is raised at 10°C/min using a differential scanning calorimeter. Examples of the differential scanning calorimeter include EXTEAR DSC6100 (SII, manufactured by Nanotechnology).

As the diamine represented by the above formula (9), for example, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3, 3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 3 ,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1 ,4-bis(4-aminophenoxy)benzene, bis(4-(4-aminophenoxy)phenyl)methane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3 -Bis(2-(4-aminophenyl)-2-propyl)benzene, 1,4-bis(2-(4-aminophenyl)-2-propyl)benzene, 3,3'-diamino-4,4 '-Dihydroxyphenylmethane, 4,4'-diamino-3,3'-dihydroxyphenylmethane, 3,3'-diamino-4,4'-dihydroxyphenyl ether, bisaminophenylflu Orene, bistoluidinefluorene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-diamino-3,3'-dihydroxyphenyl ether, 3,3'-diamino- 4,4'-dihydroxybiphenyl, 4,4'-diamino-2,2'-dihydroxybiphenyl, etc. are mentioned. Among them, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 1,3-bis(2-(4-aminophenyl)-2-propyl )Benzene, 1,4-bis(2-(4-aminophenyl)-2-propyl)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy) Benzene and 1,4-bis(4-aminophenoxy)benzene are preferable, and from the viewpoint of excellent solubility and heat resistance, 1,3-bis(2-(4-aminophenyl)-2-propyl)benzene, 1 ,4-bis(2-(4-aminophenyl)-2-propyl)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1, 4-bis(4-aminophenoxy)benzene is more preferred.

As the acid anhydride represented by the above formula (10), for example, phthalic anhydride, 3-methylphthalic anhydride, 4-methylphthalic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, 1,8 -Naphthalic anhydride, 2,3-anthracene dicarboxylic anhydride, 4-tert-butylphthalic anhydride, 4-ethynylphthalic anhydride, 4-phenylethynylphthalic anhydride, 4-fluorophthalic anhydride, 4-chlorophthalic anhydride, 4-bromophthalic anhydride, 3,4-dichlorophthalic anhydride, and the like.

As the monoamine represented by the above formula (11), for example, aniline, o-toluidine, m-toluidine, p-toluidine, 2,4-dimethylaniline, 3,4-dimethylaniline, 3,5-dimethylaniline , 2-tert-butylaniline, 3-tert-butylaniline, 4-tert-butylaniline, 1-naphthylamine, 2-naphthylamine, 1-aminoanthracene, 2-aminoanthracene, 9-aminoanthracene, 1 -Aminopyrene, 3-chloroaniline, o-anisidine, m-anisidine, p-anisidine, 1-amino-2-methylnaphthalene, 2,3-dimethylaniline, 2,4-dimethylaniline, 2,5 -Dimethylaniline, 3,4-dimethylaniline, 4-ethylaniline, 4-ethynylaniline, 4-isopropylaniline, 4-(methylthio)aniline, N,N-dimethyl-1,4-phenylenediamine, etc. Can be mentioned.

As the phenolic hydroxyl group-containing monoamine represented by the above formula (12), for example, 3-aminophenol, 4-aminophenol, 4-amino-o-cresol, 5-amino-o-cresol, 4-amino- 2,3-xylenol, 4-amino-2,5-xylenol, 4-amino-2,6-xylenol, 4-amino-1-naphthol, 5-amino-2-naphthol, 6- And amino-1-naphthol and 4-amino-2,6-diphenylphenol. Among them, 4-amino-o-cresol, 5-amino-o-cresol, and 3-aminophenol are preferable because they are excellent in availability and storage stability, and a high glass transition temperature is obtained after curing.

When the imide oligomer according to the present invention is produced by the above-described production method, the imide oligomer according to the present invention is a plurality of types of imide oligomers having a structure represented by the above formula (1-1) or the above formula (1). It is obtained by being contained in a mixture (imide oligomer composition) of a plurality of types of imide oligomers having a structure represented by -2) and each raw material. Since the imide oligomer composition has an imidation ratio of 70% or more, when used as a curing agent, a cured product having more excellent mechanical strength at high temperature and long-term heat resistance at high temperature can be obtained.

A preferable lower limit of the imidation ratio of the imide oligomer composition is 75%, and a more preferable lower limit is 80%. Moreover, although there is no particular upper limit with a preferable imidation ratio of the said imide oligomer composition, the practical upper limit is 98%.

In addition, the ``imidation rate'' is measured by a total reflection measurement method (ATR method) using a Fourier transform infrared spectrophotometer (FT-IR), and the peak absorbance in the vicinity of 1660 cm ^-1 derived from the carbonyl group of amic acid It can be derived from the area by the following equation. Examples of the Fourier transform infrared spectrophotometer include UMA600 (manufactured by Agilent Technologies). In addition, the "peak absorbance area of the amic acid oligomer" in the following formula is, after reacting an acid dianhydride with a diamine or a monoamine containing a phenolic hydroxyl group, the solvent is removed by evaporation without performing an imidation step. It is the absorbance area of the amic acid oligomer obtained by doing it.

Imidation rate (%) = 100 × (1-(peak absorbance area after imidization) ÷ (peak absorbance area of amic acid oligomer))

From the viewpoint of solubility in the case where the imide oligomer composition is used as a curable resin composition as a curing agent, it is preferable to dissolve 3 g or more with respect to 10 g of tetrahydrofuran at 25°C.

It is preferable that the said imide oligomer composition has a melting|fusing point of 200 degreeC or less from the viewpoint of handling property in the case where it is used for a curable resin composition as a curing agent. The melting point of the imide oligomer composition is more preferably 190°C or less, and still more preferably 180°C or less.

Further, the lower limit of the melting point of the imide oligomer composition is not particularly limited, but it is preferably 60°C or higher.

The preferred lower limit of the content of the imide oligomer according to the present invention in 100 parts by weight of the total amount of the curable resin and the imide oligomer is 20 parts by weight, and the preferred upper limit is 80 parts by weight. When the content of the imide oligomer according to the present invention is within this range, the cured product of the resulting curable resin composition is more excellent in mechanical strength at high temperature and long-term heat resistance at high temperature. A more preferable lower limit of the content of the imide oligomer according to the present invention is 25 parts by weight, and a more preferable upper limit is 75 parts by weight.

The curable resin composition of the present invention may contain other curing agents in addition to the imide oligomer according to the present invention within a range that does not impair the object of the present invention in order to improve workability in an uncured state.

Examples of the other curing agents include phenolic curing agents, thiol curing agents, amine curing agents, acid anhydride curing agents, cyanate curing agents, and active ester curing agents. Among them, a phenolic curing agent, an acid anhydride curing agent, a cyanate curing agent, and an active ester curing agent are preferable.

When the curable resin composition of the present invention contains the other curing agent, a preferable upper limit of the content ratio of the other curing agent in the entire curing agent is 70% by weight, a more preferable upper limit is 50% by weight, and a more preferable upper limit is 30% by weight. .

The curable resin composition of the present invention contains a curable resin.

Examples of the curable resin include epoxy resin, acrylic resin, phenol resin, cyanate resin, isocyanate resin, maleimide resin, benzoxazine resin, silicone resin, fluorine resin, polyimide resin, and phenoxy resin. Among them, an epoxy resin is preferred. Moreover, these curable resins may be used individually, and 2 or more types may be mixed and used for them.

Moreover, in the case of film processing, the curable resin is preferably in a liquid or semi-solid form at 25°C, and more preferably in a liquid form in order to improve handling properties.

Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, 2,2'-diallylbisphenol A type epoxy resin, hydrogenated bisphenol Type epoxy resin, propylene oxide added bisphenol A type epoxy resin, resorcinol type epoxy resin, biphenyl type epoxy resin, sulfide type epoxy resin, diphenyl ether type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin , Fluorene type epoxy resin, naphthylene ether type epoxy resin, phenol novolak type epoxy resin, orthocresol novolac type epoxy resin, dicyclopentadiene novolac type epoxy resin, biphenyl novolak type epoxy resin, naphthalenephenol furnace Rock-type epoxy resins, glycidylamine-type epoxy resins, alkyl polyol-type epoxy resins, rubber-modified epoxy resins, and glycidyl ester compounds. Among them, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol E type epoxy resin, and a resorcinol type epoxy resin are preferred from the viewpoint of low viscosity and easy to adjust the processability at room temperature of the resulting curable resin composition. .

It is preferable that the curable resin composition of this invention contains a hardening accelerator. By containing the curing accelerator, the curing time can be shortened and productivity can be improved.

Examples of the curing accelerator include an imidazole-based curing accelerator, a tertiary amine curing accelerator, a phosphine curing accelerator, a photobase generator, and a sulfonium salt curing accelerator. Among them, from the viewpoint of storage stability and curability, an imidazole-based curing accelerator and a phosphine curing accelerator are preferable.

The curing accelerator may be used alone or in combination of two or more.

The content of the curing accelerator is preferably 0.8% by weight based on the total weight of the curable resin, the imide oligomer, and the curing accelerator. When the content of the curing accelerator is 0.8% by weight or more, the effect of shortening the curing time becomes more excellent. A more preferable lower limit of the content of the curing accelerator is 1% by weight.

Moreover, from a viewpoint of adhesiveness etc., a preferable upper limit of the content of the curing accelerator is 10% by weight, and a more preferable upper limit is 5% by weight.

It is preferable that the curable resin composition of this invention contains an inorganic filler.

By containing the above inorganic filler, the curable resin composition of the present invention is more excellent in moisture absorption reflow resistance, plating resistance, and workability, while maintaining excellent adhesiveness and long-term heat resistance at high temperatures.

The inorganic filler is preferably at least any one of silica and barium sulfate. By containing at least any of silica and barium sulfate as the inorganic filler, the curable resin composition of the present invention is more excellent in moisture absorption reflow resistance, plating resistance, and workability.

Examples of other inorganic fillers other than the silica and barium sulfate include alumina, aluminum nitride, boron nitride, silicon nitride, glass powder, glass frit, glass fiber, carbon fiber, inorganic ion exchanger, and the like. .

The above inorganic fillers may be used alone or in combination of two or more.

The preferred lower limit of the average particle diameter of the inorganic filler is 50 nm, and the preferred upper limit is 4 µm. When the average particle diameter of the inorganic filler is within this range, the resulting curable resin composition is more excellent in coatability and processability. The more preferable lower limit of the average particle diameter of the inorganic filler is 100 nm, and the more preferable upper limit is 3 μm.

The content of the inorganic filler is a preferable lower limit of 10 parts by weight and a preferable upper limit of 150 parts by weight based on 100 parts by weight of the total of the curable resin and the imide oligomer. When the content of the inorganic filler is within this range, the resulting curable resin composition is more excellent in moisture absorption reflow resistance, plating resistance, and workability. A more preferable lower limit of the content of the inorganic filler is 20 parts by weight.

The curable resin composition of the present invention may contain a flow modifier for the purpose of improving coatability and shape retention to an adherend in a short time.

Examples of the flow control agent include fumed silica such as aerosol, layered silicate, and the like.

The flow modifier may be used alone or in combination of two or more.

Further, as the flow modifier, those having an average particle diameter of less than 100 nm are preferably used.

The content of the flow modifier is a preferable lower limit of 0.1 parts by weight and a preferable upper limit of 50 parts by weight based on 100 parts by weight of the total of the curable resin and the imide oligomer. When the content of the flow modifier is within this range, the effect of improving the coatability and shape retention to an adherend in a short time becomes more excellent. A more preferable lower limit of the content of the flow modifier is 0.5 parts by weight, and a more preferable upper limit is 30 parts by weight.

The curable resin composition of the present invention may contain an organic filler for the purpose of relieving stress and imparting toughness.

Examples of the organic fillers include silicone rubber particles, acrylic rubber particles, urethane rubber particles, polyamide particles, polyamideimide particles, polyimide particles, benzoguanamine particles, and core shell particles thereof. . Among them, polyamide particles, polyamideimide particles, and polyimide particles are preferable.

The organic fillers may be used alone or in combination of two or more.

The content of the organic filler is preferably an upper limit of 300 parts by weight based on 100 parts by weight of the total amount of the curable resin and the imide oligomer. When the content of the organic filler is within this range, the cured product of the curable resin composition obtained is more excellent in toughness and the like while maintaining excellent adhesiveness and the like. A more preferable upper limit of the content of the organic filler is 200 parts by weight.

The curable resin composition of the present invention may contain a flame retardant.

Examples of the flame retardant include metal hydrates such as boehmite type aluminum hydroxide, aluminum hydroxide, and magnesium hydroxide, halogen-based compounds, phosphorus-based compounds, nitrogen compounds, and the like. Among them, boehmite type aluminum hydroxide is preferred.

The flame retardant may be used alone or in combination of two or more.

The content of the flame retardant is a preferable lower limit of 5 parts by weight and a preferable upper limit of 200 parts by weight based on 100 parts by weight of the total amount of the curable resin and the imide oligomer. When the content of the flame retardant is within this range, the resulting curable resin composition is excellent in flame retardancy while maintaining excellent adhesion and the like. A more preferable lower limit of the content of the flame retardant is 10 parts by weight, and a more preferable upper limit is 150 parts by weight.

The curable resin composition of the present invention may contain a polymer compound within a range that does not impair the object of the present invention. The polymer compound serves as a film forming component.

The polymer compound may have a reactive functional group.

As said reactive functional group, an amino group, a urethane group, an imide group, a hydroxyl group, a carboxyl group, an epoxy group, etc. are mentioned, for example.

In addition, the polymer compound may form a phase separation structure in a cured product, or may not form a phase separation structure. When the polymer compound does not form a phase-separated structure in the cured product, the polymer compound is a polymer compound having an epoxy group as the reactive functional group in terms of superior mechanical strength at high temperature, long-term high temperature heat resistance and moisture resistance desirable.

The curable resin composition of the present invention may contain a solvent from the viewpoint of coating properties and the like.

The solvent is preferably a non-polar solvent having a boiling point of 120° C. or less, or an aprotic polar solvent having a boiling point of 120° C. or less from the viewpoint of coating properties and storage stability.

Examples of the non-polar solvent having a boiling point of 120° C. or less or an aprotic polar solvent having a boiling point of 120° C. or less include, for example, a ketone-based solvent, an ester-based solvent, a hydrocarbon-based solvent, a halogen-based solvent, an ether-based solvent, and a nitrogen-containing solvent. And the like.

Examples of the ketone solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone.

As said ester solvent, methyl acetate, ethyl acetate, isobutyl acetate, etc. are mentioned, for example.

Examples of the hydrocarbon-based solvent include benzene, toluene, normal hexane, isohexane, cyclohexane, methylcyclohexane, and normal heptane.

Examples of the halogen-based solvent include dichloromethane, chloroform, and trichloroethylene.

Examples of the ether solvent include diethyl ether, tetrahydrofuran, 1,4-dioxane, and 1,3-dioxolane.

As said nitrogen-containing solvent, acetonitrile etc. are mentioned, for example.

Among them, at least one selected from the group consisting of a ketone solvent having a boiling point of 60°C or higher, an ester solvent having a boiling point of 60°C or higher, and an ether solvent having a boiling point of 60°C or higher from the viewpoint of handling properties and solubility of imide oligomers. Paper is preferred. As such a solvent, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, isobutyl acetate, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, etc. are mentioned, for example.

In addition, the "boiling point" means a value measured under a condition of 101 kPa, or a value converted to 101 kPa in a boiling point conversion chart.

The preferable lower limit of the content of the solvent in the curable resin composition of the present invention is 20% by weight, and the preferable upper limit is 90% by weight. When the content of the solvent is within this range, the curable resin composition of the present invention has more excellent coatability and the like. The more preferable lower limit of the content of the solvent is 30% by weight, and the more preferable upper limit is 80% by weight.

The curable resin composition of the present invention may contain a reactive diluent within a range that does not impair the object of the present invention.

As the reactive diluent, a reactive diluent having two or more reactive functional groups per molecule is preferable from the viewpoint of adhesion reliability.

The curable resin composition of the present invention may further contain additives such as a coupling agent, a dispersant, a storage stabilizer, a bleed inhibitor, a flux agent, a leveling agent, a rust inhibitor, and an adhesion imparting agent.

As a method for producing the curable resin composition of the present invention, for example, using a mixer such as a homodisper, a universal mixer, a Banbury mixer, and a kneader, the curable resin, the imide oligomer according to the present invention, and ion trapping And a method of mixing an agent and a solvent to be added as necessary.

By coating the curable resin composition of the present invention on a base film and drying it, a curable resin composition film made of the curable resin composition of the present invention can be obtained, and the curable resin composition film is cured to obtain a cured product.

In the curable resin composition of the present invention, it is preferable that the initial adhesive strength of the cured product to the copper foil is 3 N/cm or more. Since the initial adhesive strength of the cured product to the copper foil is 3 N/cm or more, the curable resin composition of the present invention can be preferably used for an adhesive for coverlay of a flexible printed circuit board. It is more preferable that it is 5 N/cm or more, and, as for the initial adhesive strength of the said hardened|cured material to copper foil, it is still more preferable that it is 6 N/cm or more.

In addition, the initial adhesive strength to the copper foil was peel strength when a 90° peel test was performed under the condition of a peel rate of 50 mm/min at 25°C using a tensile tester for a test piece cut into a width of 1 cm. It can be measured as As the test piece, a polyimide substrate (manufactured by Toray DuPont, "Kafton 100H", 25 μmt) was laminated on one side of a curable resin composition film having a thickness of 20 μm, and a copper foil having a thickness of 35 μm was laminated on the other side, What is obtained by heating at 190 degreeC for 1 hour is used. The initial adhesive strength means a value measured within 24 hours after preparation of the test piece. The said curable resin composition film can be obtained by coating a curable resin composition on a base film and drying. As the copper foil, a glossy surface having an electrolytic copper foil (manufactured by Fukuda Metal Foil Powder Co., Ltd., "UN series", glossy surface roughness (Ra) of 0.25 µm) can be used. Examples of the tensile tester include UCT-500 (manufactured by ORIENTEC).

It is preferable that the curable resin composition of the present invention has an adhesive strength of 3 N/cm or more to the copper foil of the cured product after being stored at 200°C for 100 hours. The curable resin composition of the present invention can be suitably used for heat-resistant adhesives such as vehicle installations because the adhesive strength of the cured product after storage at 200° C. for 100 hours is 3 N/cm or more. The adhesion of the cured product to the copper foil after storage at 200° C. for 100 hours is more preferably 5 N/cm or more, and still more preferably 6 N/cm or more.

In particular, the curable resin composition of the present invention preferably has an adhesive strength of 3 N/cm or more to the copper foil of the cured product even after storage at 200°C for 200 hours. Thereby, even after storage under high temperature conditions over a long period of time, such as 1000 hours at 175°C, a decrease in adhesive strength can be further suppressed.

In addition, the adhesion to the copper foil of the cured product after storage at 200°C for 100 hours is the same as the method for measuring the initial adhesive strength described above, and after storing the prepared test piece at 200°C for 100 hours, it is left to cool to 25°C, It means a value measured by the same method as the initial adhesive strength within 24 hours after standing to cool.

In the curable resin composition of the present invention, it is preferable that the water absorption rate of the cured product is 1.5% or less after exposure to a high-temperature, high-humidity environment of 85°C and 85%RH for 24 hours. When the water absorption rate of the cured product is 1.5% or less, the curable resin composition of the present invention is more excellent in initial adhesiveness, high temperature long-term heat resistance, and reliability at the time of moisture absorption. The water absorption rate of the cured product is more preferably 1.2% or less, and still more preferably 1.0% or less.

In addition, the water absorption rate of the cured product after exposure to the above 85°C and 85%RH high-temperature, high-humidity environment for 24 hours can be determined by a change in the weight of the cured product before and after exposure. Specifically, after measuring the weight of the cured product before exposure, it is exposed under a high temperature and high humidity environment of 85°C and 85%RH for 24 hours, and the weight of the cured product after exposure is measured, whereby the water absorption rate of the cured product can be derived from the following equation. .

Water absorption rate (%) = 100 × (((weight after exposure)-(weight before exposure)) ÷ (weight before exposure))

As a cured product for measuring the water absorption, a curable resin composition film having a thickness of 50 mm x 50 mm and a thickness of 400 µm is heated at 190°C for 1 hour.

Although the curable resin composition of the present invention can be used for a wide range of applications, it can be suitably used for electronic material applications where particularly high heat resistance is required. For example, die attach agents for aviation, automotive electrical control unit (ECU) applications and power device applications using SiC or GaN, adhesives for power overlay packages, curable resin compositions for printed wiring boards, and flexible printed circuit boards. It can be used for coverlay adhesives, copper clad laminates, semiconductor bonding adhesives, interlayer insulating films, prepregs, encapsulants for LEDs, curable resin compositions for structural materials, and the like. Among them, it is preferably used for adhesive applications. The adhesive comprising the curable resin composition of the present invention is also one of the present invention.

The curable resin composition film can be preferably used as an adhesive film. An adhesive film formed by using the curable resin composition of the present invention is also one of the present inventions.

Further, a coverlay film having a base film and a layer comprising a cured product of the curable resin composition of the present invention formed on the base film is also one of the present inventions.

Further, a base film, a layer made of a cured product of the curable resin composition of the present invention formed on the base film, and a flexible copper clad laminate having a copper foil are also one of the present inventions.

According to the present invention, it is possible to provide a curable resin composition capable of obtaining a cured product excellent in high temperature long-term heat resistance, moisture absorption reflow resistance, and plating resistance. Further, according to the present invention, an adhesive comprising the curable resin composition, an adhesive film formed using the curable resin composition, and a coverlay film having a cured product of the curable resin composition and a flexible copper clad laminate can be provided. have.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Synthesis Example 1 (Preparation of Imide Oligomer Composition A))

1,4-bis(2-(4-aminophenyl)-2-propyl)benzene (manufactured by Mitsui Chemical Fine, ``bisaniline P'') 17.2 parts by weight of N-methylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., ``NMP ") It was dissolved in 400 parts by weight. To the obtained solution was added 52.0 parts by weight of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.), stirred at 25°C for 2 hours, and reacted to prepare an amic acid oligomer solution. Got it. After removing N-methylpyrrolidone under reduced pressure from the obtained amic acid oligomer solution, the imide oligomer composition A (97% imidation ratio) was obtained by heating at 300°C for 2 hours.

In addition, by ¹ H-NMR, GPC and FT-IR analysis, the imide oligomer composition A is an imide oligomer having a structure represented by the above formula (1-1) (A is a group represented by the following formula (13), B confirmed that it contained the group represented by following formula (14)). Moreover, the number average molecular weight of the imide oligomer which has a structure represented by the formula (1-1) was 1390. In addition, the imide oligomer composition A is an imide oligomer having a structure represented by the formula (1-1), and an imide oligomer represented by the formula (4-1) and an imide represented by the formula (4-3). It confirmed that it contained an oligomer (all, A is a group represented by following formula (13), B is a group represented by following formula (14)).

[Formula 13]

In Formula (13), * is a bonding position.

[Formula 14]

In Formula (14), * is a bonding position.

(Synthesis Example 2 (Preparation of Imide Oligomer Composition B))

21.8 parts by weight of 3-aminophenol was dissolved in 400 parts by weight of N-methylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., "NMP"). To the obtained solution, 17.2 parts by weight of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride was added, stirred at 25°C for 2 hours, and reacted to obtain an amic acid oligomer solution. After removing N-methylpyrrolidone under reduced pressure from the obtained amic acid oligomer solution, the imide oligomer composition B (96% imidation ratio) was obtained by heating at 300°C for 2 hours.

In addition, by ¹ H-NMR, GPC and FT-IR analysis, the imide oligomer composition B is an imide oligomer having a structure represented by the above formula (1-2) (A is a group represented by the above formula (13), Ar confirmed that it contained a group represented by following formula (15)). Moreover, the number average molecular weight of the imide oligomer which has a structure represented by the formula (1-2) was 630. In addition, the imide oligomer composition B is an imide oligomer having a structure represented by the formula (1-2), and an imide oligomer represented by the formula (5-1) (A is a group represented by the formula (13), R was confirmed to contain a hydrogen atom).

[Formula 15]

In Formula (15), * is a bonding position.

(Examples 1 to 10, Comparative Examples 1 and 2)

According to the blending ratios described in Tables 1 and 2, each material was stirred and mixed to prepare each curable resin composition of Examples 1 to 10 and Comparative Examples 1 and 2.

Each obtained curable resin composition was coated on a base PET film so as to have a thickness of about 20 µm and dried to obtain a curable resin composition film.

<Evaluation>

The following evaluation was performed about each curable resin composition and each curable resin composition film obtained in Examples and Comparative Examples. The results are shown in Tables 1 and 2.

(Initial adhesion)

Each curable resin composition obtained in Examples and Comparative Examples was coated on a polyimide substrate (manufactured by Toray DuPont, "Kafton 100H", 25 µm) so that the thickness was about 20 µm, and dried to make an adhesive film Got it. The obtained adhesive film was cut to a width of 1 cm, and a copper foil having a thickness of 35 µm (manufactured by Fukuda Metal Foil Powder Co., Ltd., a glossy surface of an electrolytic copper foil, "CF-T8G-UN-35") was laminated on the adhesive side side, and then at 190°C , 3 MPa and 1 hour, hot pressing was performed, the adhesive layer was cured to obtain a test piece. For the test piece within 24 hours after production, a 90° peel test was performed at 25°C with a peel rate of 50 mm/min at 25°C with a tensile tester (manufactured by ORIENTEC, “UCT-500”) to measure the peel strength, The obtained peel strength was taken as the initial adhesive strength.

Initial adhesion was evaluated as "◎" when the initial adhesive strength was 6 N/cm or more, "○" when 3 N/cm or more and less than 6 N/cm, and "x" when it was less than 3 N/cm.

(High temperature long term heat resistance)

For the test piece obtained in the same manner as the "(initial adhesion)", it was stored at 175°C for 1000 hours, then left to cool to 25°C, and the same as the "(initial adhesion)" for the test piece within 24 hours after standing to cool. The peel strength was measured by the method, and the obtained peel strength was taken as the adhesive force after 1000 hours at 175°C.

When the adhesive strength after 1000 hours at 175°C is 6 N/cm or more, “◎”, when 3 N/cm or more and less than 6 N/cm are “○”, and when it is less than 3 N/cm, “×”, high temperature long-term Heat resistance (175°C, 1000 hours) was evaluated.

Further, for the test piece obtained in the same manner as in the above "(initial adhesion)", the test piece was stored at 200°C for 100 hours or 200 hours, then allowed to cool to 25°C, and the test piece within 24 hours after standing to cool was referred to as "(initial Adhesion)", the peel strength was measured, and the obtained peel strength was made into the adhesive force after 200 degreeC and 100 hours, or the adhesive force after 200 degreeC and 200 hours.

When the adhesive strength after 200°C and 100 hours is 6 N/cm or more, “◎”, when 3 N/cm or more and less than 6 N/cm are “○”, and when it is less than 3 N/cm, “×”, high temperature long-term Heat resistance (200°C, 100 hours) was evaluated.

When the adhesive strength after 200°C and 200 hours is 6 N/cm or more, “◎”, when 3 N/cm or more and less than 6 N/cm are “○”, and when it is less than 3 N/cm, “×”, high temperature long-term Heat resistance (200°C, 200 hours) was evaluated.

(Moisture Reflow Resistance)

With respect to the test piece obtained in the same manner as in the above "(initial adhesiveness)", a moisture absorption reflow test was carried out by heating at 260°C for 20 seconds after being allowed to stand for 72 hours in an environment of 40°C and 90% RH. . About the test piece after the moisture absorption reflow test, the presence or absence of air bubbles was visually confirmed.

Evaluating the moisture absorption reflow resistance by setting ``○'' when no air bubbles were identified, ``△'' when 1 or 2 air bubbles were identified, and ``x'' when 3 or more air bubbles were identified I did.

(Plating resistance)

Each curable resin composition obtained in Examples and Comparative Examples was coated on a polyimide substrate (manufactured by Toray DuPont, "Kafton 100H", thickness 25 µm) so as to have a thickness of about 20 µm, and dried to form an adhesive film. Got it. An opening of 10 mm x 10 mm was formed in the obtained adhesive film and bonded to a copper-clad laminate comprising a copper wiring pattern having L/S = 100 µm/100 µm and a thickness of 18 µm and a polyimide film having a thickness of 50 µm. ) To prepare a sample for FPC evaluation. In addition, bonding was performed by hot pressing on the conditions of 190 degreeC, 3 MPa, and 1 hour.

The obtained sample for FPC evaluation was plated using a commercially available electroless nickel plating bath and an electroless gold plating bath at 80°C to 90°C under the conditions of 5 μm nickel and 0.05 μm gold. Observation of the end of the adhesive film at the opening with an optical microscope, "○" when leaching of the plating solution was not confirmed, "△" when leaching of the plating solution was confirmed within a range of less than 200 μm from the end of the adhesive film, and leaching of the plating solution. The case where it was confirmed from the end of the adhesive film to the range of 200 µm or more was referred to as "x", and plating resistance was evaluated.

(Absorption rate)

After peeling off the base PET film from each curable resin composition film obtained in Examples and Comparative Examples, it was laminated and cut to obtain a laminated film having a thickness of 50 mm x 50 mm and a thickness of 400 μm. A cured product was obtained by heating the obtained laminated film at 190°C for 1 hour. After measuring the weight (weight before exposure) of the obtained hardened|cured material, it exposed under the high temperature and high humidity environment of 85 degreeC and 85%RH for 24 hours. The weight of the cured product after exposure to a high temperature and high humidity environment (weight after exposure) was measured, and the water absorption rate of the cured product was derived from the above-described equation.

Industrial availability

According to the present invention, it is possible to provide a curable resin composition capable of obtaining a cured product excellent in high temperature long-term heat resistance, moisture absorption reflow resistance, and plating resistance. Further, according to the present invention, an adhesive comprising the curable resin composition, an adhesive film formed using the curable resin composition, and a coverlay film having a cured product of the curable resin composition and a flexible copper clad laminate can be provided. have.

Claims (12)

A curable resin composition comprising a curable resin, an imide oligomer having an imide skeleton in a main chain and a crosslinkable functional group at a terminal, and an ion scavenger. The method of claim 1,
The ion scavenger is a curable resin composition that is an anion exchanger or a positive ion exchanger. The method according to claim 1 or 2,
The curable resin composition, wherein the ion scavenger is particles having an average particle diameter of 10 μm or less. The method of claim 1, 2 or 3,
The content of the ion scavenger is 0.1 parts by weight or more and 200 parts by weight or less based on 100 parts by weight of the total amount of the curable resin and the imide oligomer. The method of claim 1, 2, 3 or 4,
The curable resin composition in which the initial adhesion of the cured product to the copper foil is 3 N/cm or more, and the adhesion of the cured product to the copper foil after storage at 200°C for 100 hours is 3 N/cm or more. The method according to claim 1, 2, 3, 4 or 5,
The curable resin composition in which the water absorption rate of the cured product after exposure to a high temperature and high humidity environment of 85°C and 85%RH for 24 hours is 1.5% or less. The method according to claim 1, 2, 3, 4, 5 or 6,
The said imide oligomer is a curable resin composition whose number average molecular weight is 4000 or less. The method of claim 1, 2, 3, 4, 5, 6 or 7,
The curable resin composition in which the crosslinkable functional group is at least any of an acid anhydride group and a phenolic hydroxyl group. An adhesive comprising the curable resin composition according to claim 1, 2, 3, 4, 5, 6, 7 or 8. An adhesive film obtained by using the curable resin composition according to claim 1, 2, 3, 4, 5, 6, 7 or 8. Consisting of a base film and a cured product of the curable resin composition according to claim 1, 2, 3, 4, 5, 6, 7 or 8 formed on the base film Layered coverlay film. Consisting of a base film and a cured product of the curable resin composition according to claim 1, 2, 3, 4, 5, 6, 7 or 8 formed on the base film A flexible copper clad laminate having a layer and a copper foil.