JP2022121514A - Curable resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a curable resin composition which has a high glass transition temperature after curing and from which a cured material having excellent thermal decomposition resistance, adhesiveness, and long-term heat resistance can be obtained; a cured material of the curable resin composition; an adhesive comprising the curable resin composition; an adhesive film using the curable resin composition; and a circuit board comprising the cured material.

SOLUTION: A curable resin composition comprises: a curable resin; an imide oligomer having an imide skeleton in the main chain, a cross-linkable functional group at a terminal, and a number average molecular weight of 4000 or less; and a curing accelerator. Initial adhesive strength of a cured material to polyimide is 3.4 N/cm or more, and adhesive strength of the cured material to polyimide, after being stored at 200°C for 100 hours, is 0.8 times or more the initial adhesive strength.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

TECHNICAL FIELD The present invention relates to a curable resin composition that has a high glass transition temperature after curing and that can give a cured product that is excellent in thermal decomposition resistance, adhesiveness, and long-term heat resistance. The present invention also relates to a cured product of the curable resin composition, an adhesive containing the curable resin composition, an adhesive film using the curable resin composition, and a circuit board having the cured product. .

Curable resins such as epoxy resins, which have low shrinkage and excellent adhesiveness, insulation, and chemical resistance, are used in many industrial products. Particularly in applications for electronic devices, curable resin compositions that give good results in solder reflow tests for short-term heat resistance and thermal cycle tests for repeated heat resistance are often used.

In recent years, automotive electric control units (ECUs) and power devices using SiC and GaN have attracted attention. However, it is required to have heat resistance (long-term heat resistance) when continuously exposed to high temperatures for a long period of time.

As a curing agent used in a curable resin composition, Patent Document 1 discloses an imide oligomer curing agent having an acid anhydride structure at both ends. Since it is insufficient, there is a problem that the resulting curable resin composition is inferior in long-term heat resistance.

On the other hand, Patent Documents 2 and 3 disclose a curable resin composition using a polyimide having a flexible siloxane skeleton or an alicyclic skeleton as a curing agent in order to improve compatibility with the curable resin. there is However, when a siloxane skeleton or an alicyclic skeleton is introduced, the glass transition temperature of the resulting cured product tends to decrease, resulting in poor mechanical strength and long-term heat resistance at the operating temperatures of ECUs, power devices, and the like. was there.
Further, Patent Document 4 discloses an imide oligomer which is formed by using an acid dianhydride having a specific structure and has phenolic hydroxyl groups or aniline amino groups at both ends. However, when such an imide oligomer is used, it is necessary to use a highly polar solvent from the viewpoint of solubility in the solvent, resulting in poor storage stability and insufficient solubility in the curable resin. As a result, the long-term heat resistance of the cured product may deteriorate due to the residue left behind without being incorporated into the cured product.

JP-A-61-270852 JP 2016-20437 A JP 2016-69651 A WO2005/100433

An object of the present invention is to provide a curable resin composition that has a high glass transition temperature after curing and can give a cured product that is excellent in thermal decomposition resistance, adhesiveness, and long-term heat resistance. Further, the present invention provides a cured product of the curable resin composition, an adhesive containing the curable resin composition, an adhesive film using the curable resin composition, and a circuit board having the cured product. intended to provide

The present invention contains a curable resin, an imide skeleton in the main chain, an imide oligomer having a crosslinkable functional group at the end, and a number average molecular weight of 4000 or less, and a curing accelerator, and a cured product for polyimide A curable resin composition having an initial adhesive strength of 3.4 N/cm or more, and a cured product having an adhesive strength to polyimide after storage at 200° C. for 100 hours is 0.8 times or more the initial adhesive strength. It is a thing.
The present invention will be described in detail below.

The present inventors have used an imide oligomer having a specific structure and a number average molecular weight of a specific value or less as a curing agent for a curable resin composition, and further specified the initial adhesive strength of the cured product to polyimide. and the adhesive strength of the cured product to polyimide after being stored at 200° C. for 100 hours was considered to be at least a specific proportion of the initial adhesive strength. As a result, the present inventors have found that a cured product having a high glass transition temperature after curing and excellent thermal decomposition resistance, adhesiveness and long-term heat resistance can be obtained, and have completed the present invention.

The curable resin composition of the present invention has an initial adhesive strength of 3.4 N/cm or more to polyimide as a cured product. Since the cured product has an initial adhesive strength of 3.4 N/cm or more to polyimide, the curable resin composition of the present invention can be suitably used as a coverlay adhesive for flexible printed circuit boards. The initial adhesive strength of the cured product to polyimide is preferably 5 N/cm or more, more preferably 6 N/cm or more.
The initial adhesive strength to the polyimide can be measured by subjecting a test piece cut to a width of 1 cm to T-shaped peeling at 25° C. and a peeling speed of 20 mm/min using a tensile tester. As the test piece, those obtained by laminating polyimide films having a thickness of 50 μm on both sides of a curable resin composition film having a thickness of 20 μm and heating at 190° C. for 1 hour are used. , means the value measured within 24 hours after the preparation of the test piece. The curable resin composition film can be obtained by applying the curable resin composition onto a base film and drying the coating. Kapton 200H (manufactured by DuPont Toray Co., Ltd.; surface roughness 0.03 to 0.07 μm) can be used as the polyimide. Examples of the tensile tester include UCT-500 (manufactured by ORIENTEC).

In the curable resin composition of the present invention, the adhesive strength of the cured product to polyimide after storage at 200° C. for 100 hours is 0.8 times or more the initial adhesive strength. The curable resin composition of the present invention has a heat resistance such as in-vehicle use because the adhesive strength to polyimide of the cured product after storage at 200 ° C. for 100 hours is at least 0.8 times the initial adhesive strength. It can be suitably used for adhesives. The adhesion of the cured product to polyimide after being stored at 200° C. for 100 hours is preferably 0.85 times or more, more preferably 0.9 times or more, the initial adhesion.
The adhesive strength of the cured product to polyimide after storage at 200 ° C. for 100 hours is up to 25 ° C. after storing a test piece prepared in the same manner as the initial adhesive strength measurement method at 200 ° C. for 100 hours. It means a value measured in the same manner as the above-mentioned initial adhesive strength within 24 hours after standing to cool.

The curable resin composition of the present invention is an imide oligomer having an imide skeleton in the main chain, a crosslinkable functional group at the end, and a number average molecular weight of 4000 or less (hereinafter also referred to as "the imide oligomer according to the present invention"). contains The imide oligomer according to the present invention is excellent in reactivity and compatibility with curable resins such as epoxy resins. By containing the imide oligomer according to the present invention, the curable resin composition of the present invention exhibits excellent mechanical strength and long-term heat resistance at high temperatures.

The crosslinkable functional group is preferably a functional group capable of reacting with an epoxy group.
Examples of functional groups capable of reacting with epoxy groups include amino groups, carboxyl groups, acid anhydride groups, phenolic hydroxyl groups, unsaturated groups, active ester groups, and maleimide groups. Among them, an acid anhydride group and/or a phenolic hydroxyl group are 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, a higher glass transition temperature can be obtained after curing by increasing the crosslink density. On the other hand, when the crosslinkable functional group is provided at one end, the functional group equivalent increases, and the content of the imide oligomer according to the present invention in the curable resin composition can be increased, so that the resulting cured product has long-term heat resistance. It will be better.

The imide oligomer according to the present invention preferably has a structure represented by the following formula (1-1) or the following formula (1-2) as the 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 excellent in reactivity and compatibility with curable resins such as epoxy resins. becomes.

In the formulas (1-1) and (1-2), A is a tetravalent group represented by the following formula (2-1) or the following formula (2-2), and the formula (1-1) Among them, B is a divalent group represented by the following formula (3-1) or the following formula (3-2), and in formula (1-2), Ar is an optionally substituted divalent is an aromatic group of

In formulas (2-1) and (2-2), * is a bonding position, and in formula (2-1), Z is a bond, an oxygen atom, or optionally substituted, a bond It is a divalent hydrocarbon group optionally having an oxygen atom at its position. The hydrogen atoms of the aromatic rings in formulas (2-1) and (2-2) may be substituted.

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

In addition, the imide oligomer according to the present invention lowers the glass transition temperature after curing and may contaminate the adherend and cause adhesion failure. is preferred.

The number average molecular weight of the imide oligomer according to the present invention is 4000 or less. When the number average molecular weight is within this range, the resulting cured product of the curable resin composition is excellent in long-term heat resistance. A preferable upper limit of the number average molecular weight of the imide oligomer according to the present invention is 3,400, and a more preferable upper limit is 2,800.
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 above formula (1-1), and is represented by the above formula (1-2). In the case of having a structure with a A more preferable lower limit of the number average molecular weight in the case of having the structure represented by the above formula (1-1) is 950, and a more preferable lower limit is 1,000. A more preferable lower limit of the number average molecular weight in the case of having the structure represented by the above formula (1-2) is 580, and a more preferable lower limit is 600.
In addition, the above-mentioned "number average molecular weight" in this specification is a value measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent and calculated by polystyrene conversion. Examples of the column used for measuring the polystyrene-equivalent number-average molecular weight by GPC include JAIGEL-2H-A (manufactured by Japan Analytical Industry Co., Ltd.).

Specifically, the imide oligomer according to the present invention is represented by the following formula (4-1), the following formula (4-2), the following formula (4-3), or the following formula (4-4). An imide oligomer or an imide oligomer represented by the following formula (5-1), (5-2), (5-3) or (5-4) below is preferable.

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

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

In formulas (6-1) and (6-2), * is a bonding position, and in formula (6-1), Z is a bond, an oxygen atom, or optionally substituted, a bond It is a divalent hydrocarbon group optionally having an oxygen atom at its position. The hydrogen atoms of the aromatic rings in formulas (6-1) and (6-2) may be substituted.

In formulas (7-1) and (7-2), * is a bonding position, and in formula (7-1), Y is a bond, an oxygen atom, or an optionally substituted divalent is a hydrocarbon group of The hydrogen atoms of the aromatic rings in formulas (7-1) and (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 and a method of reacting with a diamine represented by (9).

In formula (8), A is the same tetravalent group as A in formula (1-1) above.

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

A specific example of the method for reacting the acid dianhydride represented by the above formula (8) with the diamine represented by the above formula (9) is shown below.
First, the diamine represented by the above formula (9) is dissolved in advance in a solvent (for example, N-methylpyrrolidone) in which the amic acid oligomer obtained by the reaction is soluble, and the resulting solution is added with the above formula (8). An acid dianhydride represented by is added and reacted to obtain an amic acid oligomer solution. Next, the solvent is removed by heating, pressure reduction, or the like, and the mixture is heated at about 200° C. or higher for 1 hour or longer to react the amic acid oligomer. By adjusting the molar ratio of the acid dianhydride represented by the above formula (8) and the diamine represented by the above formula (9), and the imidization conditions, it has a desired number average molecular weight, and both An imide oligomer having a structure represented by the above formula (1-1) at the end can be obtained.
Further, by replacing a part of the acid dianhydride represented by the above formula (8) with the acid anhydride represented by the following formula (10), it has a desired number average molecular weight and one end has the above An imide oligomer having a structure represented by the formula (1-1) and having a structure derived from an acid anhydride represented by the following formula (10) at the other end can be obtained. In this case, the acid dianhydride represented by the above formula (8) and the acid anhydride represented by the following formula (10) may be added simultaneously or separately.
Furthermore, by replacing a part of the diamine represented by the above formula (9) with a monoamine represented by the following formula (11), it has a desired number average molecular weight, and one end has the above formula (1-1) ) and having at the other end a structure derived from a monoamine represented by the following formula (11). In this case, the diamine represented by the above formula (9) and the monoamine represented by the following formula (11) may be added simultaneously or separately.

In formula (10), Ar is an optionally substituted divalent aromatic group.

式（１１）中、Ａｒは、置換されていてもよい１価の芳香族基であり、Ｒ^５及びＲ^６は、それぞれ独立に、水素原子又は１価の炭化水素基である。

In formula (11), Ar is an optionally substituted monovalent aromatic group, 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 above formula (1-2), for example, an acid dianhydride represented by the above formula (8) and the following formula Examples thereof include a method of reacting with a phenolic hydroxyl group-containing monoamine represented by (12).

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

A specific example of the method for reacting the acid dianhydride represented by the above formula (8) with the phenolic hydroxyl group-containing monoamine represented by the above formula (12) is shown below.
First, a phenolic hydroxyl group-containing monoamine represented by formula (12) is dissolved in advance in a solvent in which the amic acid oligomer obtained by the reaction is soluble (for example, N-methylpyrrolidone, etc.), and the resulting solution is added with the above formula An acid dianhydride represented by (8) is added and reacted to obtain an amic acid oligomer solution. Next, the solvent is removed by heating, pressure reduction, or the like, and the mixture is heated at about 200° C. or higher for 1 hour or longer to react the amic acid oligomer. 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, a desired number average molecular weight can be obtained. An imide oligomer having a structure represented by the above formula (1-2) at both ends can be obtained.
Further, by replacing 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 end has the above formula An imide oligomer having a structure represented by (1-2) and having a structure derived from a monoamine represented by the above formula (11) at the other end can be obtained. In this case, the phenolic hydroxyl group-containing monoamine represented by the above formula (12) and the monoamine represented by the above formula (11) may be added simultaneously or separately.

Examples of the acid dianhydride represented by the above formula (8) include pyromellitic dianhydride, 3,3′-oxydiphthalic dianhydride, 3,4′-oxydiphthalic dianhydride, 4,4 '-oxydiphthalic dianhydride, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, 4,4'-bis(2,3-dicarboxylphenoxy)diphenyl ether dianhydride, p -phenylene bis(trimellitate anhydride), 2,3,3',4'-biphenyltetracarboxylic dianhydride and the like.
Among them, aromatic acid dianhydrides having a melting point of 240° C. or less are preferable as the acid dianhydrides used as raw materials for the imide oligomer according to the present invention, since they are excellent in solubility and heat resistance. is more preferably 220° C. or less, more preferably 200° C. or less, 3,4′-oxydiphthalic dianhydride (melting point 180° C.), 4 ,4′-(4,4′-isopropylidenediphenoxy)diphthalic anhydride (melting point 190° C.) is particularly preferred.
In this specification, the "melting point" means a value measured as an endothermic peak temperature when the temperature is raised at 10°C/min using a differential scanning calorimeter. Examples of the differential scanning calorimeter include EXTEAR DSC6100 (manufactured by SII Nano Technology Co., Ltd.).

Examples of diamines represented by the above formula (9) include 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-amino phenyl)-2-propyl)benzene, 3,3′-diamino-4,4′-dihydroxyphenylmethane, 4,4′-diamino-3,3′-dihydroxyphenylmethane, 3,3′-diamino-4, 4'-dihydroxyphenyl ether, bisaminophenylfluorene, 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 and the like. 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, 1,4-bis( 4-Aminophenoxy)benzene is preferred, and 1,3-bis(2-(4-aminophenyl)-2-propyl)benzene, 1,4-bis(2-(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.

Examples of acid anhydrides represented by the above formula (10) include phthalic anhydride, 3-methylphthalic anhydride, 4-methylphthalic anhydride, 1,2-naphthalic anhydride, and 2,3-naphthalic anhydride. acid anhydride, 1,8-naphthalic anhydride, 2,3-anthracenedicarboxylic anhydride, 4-tert-butyl phthalic anhydride, 4-ethynyl phthalic anhydride, 4-phenylethynyl phthalic anhydride, 4-fluorophthalic anhydride, 4-chlorophthalic anhydride, 4-bromophthalic anhydride, 3,4-dichlorophthalic anhydride and the like.

Monoamines represented by the above formula (11) include, 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-dimethyl aniline, 4-ethylaniline, 4-ethynylaniline, 4-isopropylaniline, 4-(methylthio)aniline, N,N-dimethyl-1,4-phenylenediamine and the like.

Examples of the phenolic hydroxyl group-containing monoamine represented by the above formula (12) include 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-amino-1-naphthol, 4 -amino-2,6-diphenylphenol and the like. Among them, 4-amino-o-cresol and 5-amino-o-cresol are preferred because they are excellent in availability and storage stability and provide a high glass transition temperature after curing.

When the imide oligomer according to the present invention is produced by the production method described above, 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 (1-2) ) and a mixture of each starting material (imide oligomer composition). When the imide oligomer composition has an imidization rate of 70% or more, it can provide a cured product having excellent mechanical strength at high temperatures and long-term heat resistance when used as a curing agent.
A preferred lower limit for the imidization rate of the imide oligomer composition is 75%, and a more preferred lower limit is 80%. Although there is no particular upper limit for the imidization rate of the imide oligomer composition, the practical upper limit is 98%.
The above-mentioned "imidation rate" is measured by a total reflection measurement method (ATR method) using a Fourier transform infrared spectrophotometer (FT-IR), and is derived from the carbonyl group of amic acid at 1660 cm ^-1 It can be derived from the peak absorbance area in the vicinity by the following formula. Examples of the Fourier transform infrared spectrophotometer include UMA600 (manufactured by Agilent Technologies). The "peak absorbance area of the amic acid oligomer" in the following formula is obtained by removing the solvent by evaporation or the like without performing the imidization step after reacting the acid dianhydride with a diamine or a phenolic hydroxyl group-containing monoamine. is the absorbance area of the amic acid oligomer obtained by
Imidation rate (%) = 100 × (1-(peak absorbance area after imidization)/(peak absorbance area of amic acid oligomer))

From the viewpoint of solubility when used as a curing agent in a curable resin composition, the imide oligomer composition preferably dissolves in an amount of 3 g or more per 10 g of tetrahydrofuran at 25°C.

The imide oligomer composition preferably has a melting point of 200° C. or lower from the viewpoint of handleability when used as a curing agent in a curable resin composition. The melting point of the imide oligomer composition is more preferably 190° C. or lower, even more preferably 180° C. or lower.
Although the lower limit of the melting point of the imide oligomer composition is not particularly limited, it is preferably 60°C or higher.

The content of the imide oligomer according to the present invention in the curable resin composition of the present invention has a preferred lower limit of 20% by weight and a preferred upper limit of 80%, based on the total weight of the curable resin, the imide oligomer, and the curing accelerator. % by weight. When the content of the imide oligomer according to the present invention is within this range, the obtained cured product has excellent mechanical strength at high temperatures and long-term heat resistance. A more preferable lower limit of the content of the imide oligomer according to the present invention is 25% by weight, and a more preferable upper limit thereof is 75% by weight.

The curable resin composition of the present invention contains other curing agents in addition to the imide oligomer according to the present invention, within a range that does not hinder the object of the present invention, in order to improve workability in an uncured state. You may
Examples of other curing agents include phenol-based curing agents, thiol-based curing agents, amine-based curing agents, acid anhydride-based curing agents, cyanate-based curing agents, active ester-based curing agents, and the like. Among them, a phenol-based curing agent, an acid anhydride-based curing agent, a cyanate-based curing agent, and an active ester-based curing agent are preferable.

When the curable resin composition of the present invention contains the other curing agent, the upper limit of the content of the other curing agent in the total curing agent is preferably 70% by weight, more preferably 50% by weight, and still more preferably. The upper limit is 30% by weight.

The curable resin composition of the present invention contains a curable resin.
Examples of the curable resins include epoxy resins, acrylic resins, phenol resins, cyanate resins, isocyanate resins, maleimide resins, benzoxazine resins, silicone resins, fluorine resins, polyimide resins, and phenoxy resins. Among them, epoxy resin is preferable. Moreover, these curable resins may be used alone, or two or more of them may be mixed and used.
In the case of film processing, the curable resin is preferably in a liquid or semi-solid form at 25° C., 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, and 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, ortho-cresol novolak type epoxy resin, dicyclopentadiene novolak type epoxy resin, biphenyl novolak type epoxy resin, naphthalenephenol novolak type epoxy resin, glycidylamine type epoxy resin, alkylpolyol type epoxy resin, Examples include rubber-modified epoxy resins and glycidyl ester compounds. Among them, bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, bisphenol E-type epoxy resin, and resorcinol-type epoxy resin are preferable because they have low viscosity and can easily adjust the processability at room temperature of the resulting curable resin composition. .

The curable resin composition of the present invention contains a curing accelerator. By containing the curing accelerator, the curing time can be shortened and the productivity can be improved.

Examples of the curing accelerator include imidazole-based curing accelerators, tertiary amine-based curing accelerators, phosphine-based curing accelerators, photobase generators, and sulfonium salt-based curing accelerators. Among these, imidazole-based curing accelerators and phosphine-based curing accelerators are preferable from the viewpoint of storage stability and curability.

The preferable lower limit of the content of the curing accelerator in the curable resin composition of the present invention is 0.8% by weight with respect to 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 is more excellent. A more preferable lower limit for the content of the curing accelerator is 1% by weight.
From the viewpoint of adhesiveness and the like, the preferred upper limit of the content of the curing accelerator is 10% by weight, and the more preferred upper limit is 5% by weight.

The curable resin composition of the present invention preferably has a tack value at 60°C that is at least twice the tack value at 25°C. When the tack value at 60°C is at least twice the tack value at 25°C, the curable resin composition of the present invention is superior in handleability at room temperature and superior in adhesion and long-term heat resistance. become a thing. The tack value at 60°C is more preferably at least 2.2 times the tack value at 25°C, and even more preferably at least 2.5 times.
The tack value at 25° C. of the curable resin composition of the present invention is preferably 20 gf/5 mmφ or less, more preferably 15 gf/5 mmφ or less, and even more preferably 10 gf/5 mmφ or less.
In this specification, the above-mentioned "tack value" means using a probe tack measuring device (e.g., tacking tester TAC-2 (manufactured by RHESCA), etc.), a probe diameter of 5 mm, a contact speed of 0.5 mm / sec, It means a tack value measured under the measurement conditions of a test speed of 0.5 mm/sec, a contact load of 0.05 MPa, and a contact time of 1 second. In addition, the tack value is a curable resin composition film obtained by coating the curable resin composition on a base film such as PET or polyimide and drying it (the thickness of the curable resin composition layer 20 μm) is obtained by measuring the tack value on the side opposite to the base film.

The curable resin composition of the present invention preferably has a surface free energy of 40 mJ/m ² or more. When the surface free energy is 40 mJ/m ² or more, the curable resin composition of the present invention becomes excellent in adhesiveness and long-term heat resistance. The surface free energy is more preferably 41 mJ/m ² or more, even more preferably 42 mJ/m ² or more.
In the present invention, the above-mentioned "surface free energy" can be calculated by the following formula after measuring the contact angle with water and methylene iodide using a contact angle meter (dropping amount 3 μL, 30 seconds after dropping). can.
γs = γsd + γsp
72.8(1+cos θH)=2(21.8γsd) ^1/2 +2(51.0γsp) ^1/2
50.8(1+cos θI)=2(48.5γsd) ^1/2 +2(2.3γsp) ^1/2
γs: surface free energy γsd: dispersion component of surface free energy γsp: polar component of surface free energy θH: contact angle to water θI: contact angle to methylene iodide The surface free energy is measured by the above-described tack value measurement method. Obtained by measuring the surface free energy on the opposite side of the substrate film to a curable resin composition film (having a thickness of the curable resin composition layer of about 20 μm) prepared in the same manner as in .

In the curable resin composition of the present invention, the adhesive strength of the cured product after storage for 24 hours in an environment of 85° C. and 85% RH is 0.8 times or more the initial adhesive strength. preferable. The curable resin composition of the present invention has an adhesive strength to polyimide of 0.8 times or more of the initial adhesive strength of the cured product after storage for 24 hours in an environment of 85° C. and 85% RH. is superior in adhesion and long-term heat resistance. The adhesive strength of the cured product after storage for 24 hours in an environment of 85 ° C. and 85% RH is more preferably 0.85 times or more, more preferably 0.9 times or more, relative to the initial adhesive strength. is more preferable.
The adhesive strength of the cured product to polyimide after being stored for 24 hours in an environment of 85 ° C. and 85% RH was measured using a test piece prepared in the same manner as the initial adhesive strength measurement method described above. It means a value measured in the same manner as the above initial adhesive strength within 24 hours after cooling to 25° C. after storing for 24 hours in a RH environment.

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

The organic filler is not particularly limited, and examples thereof 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 preferred.

The preferred lower limit of the content of the organic filler is 10 parts by weight, and the preferred upper limit thereof is 500 parts by weight with respect to 100 parts by weight of the curable resin. When the content of the organic filler is within this range, the obtained cured product is superior in toughness and the like while maintaining excellent adhesiveness and the like. A more preferable lower limit for the content of the organic filler is 30 parts by weight, and a more preferable upper limit is 400 parts by weight.

The curable resin composition of the present invention may contain an inorganic filler for the purpose of lowering the coefficient of linear expansion after curing to reduce warpage or improving adhesion reliability. In addition, the inorganic filler can also be used as a flow control agent.

Examples of the inorganic filler include silica such as fumed silica and colloidal silica, barium sulfate, alumina, aluminum nitride, boron nitride, silicon nitride, glass powder, glass frit, glass fiber, carbon fiber, inorganic ion exchangers, and the like. is mentioned.

As for the content of the inorganic filler, a preferred lower limit is 10 parts by weight and a preferred upper limit is 500 parts by weight with respect to 100 parts by weight of the curable resin. When the content of the inorganic filler is within this range, excellent effects such as improved adhesion reliability can be achieved while maintaining excellent processability and the like. A more preferable lower limit for the content of the inorganic filler is 30 parts by weight, and a more preferable upper limit is 400 parts by weight.

The curable resin composition of the present invention may contain a polymer compound as long as the object of the present invention is not impaired. The polymer compound serves as a film-forming component.

The polymer compound may have a reactive functional group.
Examples of the reactive functional groups include amino groups, urethane groups, imide groups, hydroxyl groups, carboxyl groups, and epoxy groups.

Moreover, the polymer compound may form a phase-separated structure in the cured product, or may not form a phase-separated structure. When the polymer compound does not form a phase separation structure in the cured product, the polymer compound has excellent mechanical strength at high temperatures, long-term heat resistance, and moisture resistance. Polymer compounds having epoxy groups are preferred.

The curable resin composition of the present invention may contain a solvent from the viewpoint of coatability and the like.
As the solvent, a non-polar solvent having a boiling point of 120° C. or lower or an aprotic polar solvent having a boiling point of 120° C. or lower is preferable from the viewpoint of coatability, storage stability, and the like.
Examples of the nonpolar solvent having a boiling point of 120° C. or lower or the aprotic polar solvent having a boiling point of 120° C. or lower include ketone solvents, ester solvents, hydrocarbon solvents, halogen solvents, ether solvents, and nitrogen-containing solvents. system solvents and the like.
Examples of the ketone solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone.
Examples of the ester solvent include methyl acetate, ethyl acetate, and isobutyl acetate.
Examples of the hydrocarbon solvent include benzene, toluene, normal hexane, isohexane, cyclohexane, methylcyclohexane, normal heptane and the like.
Examples of the halogen-based solvent include dichloromethane, chloroform, and trichlorethylene.
Examples of the ether solvent include diethyl ether, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane and the like.
Examples of the nitrogen-containing solvent include acetonitrile.
Among them, a group consisting of ketone-based solvents with a boiling point of 60°C or higher, ester-based solvents with a boiling point of 60°C or higher, and ether-based solvents with a boiling point of 60°C or higher, from the viewpoint of handleability, solubility of imide oligomers, etc. At least one more selected is preferred. Examples of such solvents include methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, isobutyl acetate, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran and the like.
The "boiling point" means a value measured under conditions of 101 kPa, or a value converted to 101 kPa using a boiling point conversion chart or the like.

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

The curable resin composition of the present invention may contain a reactive diluent as long as the object of the present invention is not impaired.
From the viewpoint of adhesion reliability, the reactive diluent is preferably a reactive diluent having two or more reactive functional groups in one molecule.

The curable resin composition of the present invention may further contain additives such as coupling agents, dispersants, storage stabilizers, bleed inhibitors, fluxing agents, organic or inorganic flame retardants.

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, a kneader, a curable resin, an imide oligomer according to the present invention, and a curing accelerator and a method of mixing the agent with a solvent or the like added as necessary.
Further, by applying the curable resin composition of the present invention onto a substrate film and drying it, a curable resin composition film made of the curable resin composition of the present invention can be obtained. A cured product can be obtained by curing the resin composition film. A cured product of the curable resin composition of the present invention is also one aspect of the present invention.

From the viewpoint of mechanical strength and long-term heat resistance, the cured product of the present invention preferably has a glass transition temperature of 150° C. or higher, more preferably 160° C. or higher.
The above glass transition temperature was measured using a dynamic viscoelasticity measuring device for a cured product having a thickness of 400 μm at a heating rate of 10° C./min, a frequency of 10 Hz, and a chuck distance of 24 mm from 0° C. to 300° C. It can be obtained as the peak temperature of the tan δ curve obtained when measured under the conditions. A cured product for measuring the glass transition temperature can be obtained by heating the curable resin composition film at 190° C. for 30 minutes. Examples of the dynamic viscoelasticity measuring device include the Rheovibron dynamic viscoelasticity automatic measuring device DDV-GP series (manufactured by A&D Co., Ltd.).

From the viewpoint of thermal decomposition resistance, the cured product of the present invention preferably has a weight loss rate of less than 2.5% at 330°C, more preferably less than 2.0%.
The weight loss rate was obtained by thermogravimetric measurement of the curable resin composition film using a thermogravimetric measurement device under conditions of temperature elevation from 30° C. to 400° C. at a temperature elevation rate of 10° C./min. It can be obtained as a percentage of the weight that has decreased up to 330°C. Examples of the thermogravimetry apparatus include EXTEAR TG/DTA6200 (manufactured by SII Nano Technology Co., Ltd.).

The curable resin composition of the present invention can be used in a wide range of applications, and is particularly suitable for electronic material applications that require high heat resistance. For example, aviation and automotive electric control unit (ECU) applications, die attach agents for power device applications using SiC and GaN, adhesives for power overlay packages, curable resin compositions for printed wiring boards, flexible printed circuit boards coverlay adhesives, copper clad laminates, semiconductor bonding adhesives, interlayer insulating films, prepregs, LED sealants, curable resin compositions for structural materials, and the like. Among others, it is preferably used for adhesives. An adhesive containing the curable resin composition of the present invention is also one aspect of the present invention.
Moreover, the curable resin film can be suitably used as an adhesive film. An adhesive film using the curable resin composition of the present invention is also one aspect of the present invention.
Furthermore, a circuit board having the cured product of the present invention is also one aspect of the present invention.

ADVANTAGE OF THE INVENTION According to this invention, it has a high glass transition temperature after hardening, and can provide the curable resin composition which can obtain the hardened|cured material which is excellent in thermal decomposition resistance, adhesiveness, and long-term heat resistance. Further, according to the present invention, a cured product of the curable resin composition, an adhesive containing the curable resin composition, an adhesive film using the curable resin composition, and a circuit having the cured product A substrate can be provided.

EXAMPLES The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to these Examples.

(Synthesis Example 1 (preparation of imide oligomer composition A))
34.5 parts by weight of 1,3-bis(2-(4-aminophenyl)-2-propyl)benzene (manufactured by Mitsui Chemicals Fine Co., Ltd., "Bisaniline M") and N-methylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., "NMP") was dissolved in 400 parts by weight. 62.0 parts by weight of 3,4'-oxydiphthalic dianhydride (manufactured by Tokyo Kasei Kogyo Co., Ltd., "3,4'-ODPA") was added to the resulting solution, and the mixture was stirred at 25°C for 2 hours to react. to obtain an amic acid oligomer solution. After removing N-methylpyrrolidone from the resulting amic acid oligomer solution under reduced pressure, the solution was heated at 300° C. for 2 hours to obtain an imide oligomer composition A (imidization rate: 92%).
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 represented by the following formula (13). It was confirmed that B contains a group represented by the following formula (14). Also, the number average molecular weight of the imide oligomer having the structure represented by the formula (1-1) was 1,380. Furthermore, the imide oligomer composition A is an imide oligomer represented by the above formula (4-1) as an imide oligomer having a structure represented by the above formula (1-1) (A is represented by the following formula (13) It was confirmed that B contains a group represented by the following formula (14).

In formula (13), * is a binding position.

In formula (14), * is a binding position.

(Synthesis Example 2 (preparation of imide oligomer composition B))
1,3-bis(2-(4-aminophenyl)-2-propyl)benzene 34.5 parts by weight, 1,4-bis(2-(4-aminophenyl)-2-propyl)benzene (Mitsui Chemicals An imide oligomer composition B (imidization rate: 92%) was obtained in the same manner as in Synthesis Example 1, except that 34.5 parts by weight of "bisaniline P" manufactured by Fine Co., Ltd. was used.
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 (1-1) (A is represented by the above formula (13). It was confirmed that B contains a group represented by the following formula (15). Also, the number average molecular weight of the imide oligomer having the structure represented by the formula (1-1) was 1,390. Furthermore, the imide oligomer composition B is an imide oligomer represented by the above formula (4-1) as an imide oligomer having a structure represented by the above formula (1-1) (A is represented by the above formula (13) It was confirmed that B contains a group represented by the following formula (15).

In formula (15), * is a binding position.

(Synthesis Example 3 (preparation of imide oligomer composition C))
34.5 parts by weight of 1,3-bis(2-(4-aminophenyl)-2-propyl)benzene, 1,3-bis(3-aminophenoxy)benzene (manufactured by Mitsui Chemicals Fine Co., Ltd., "APB-N ”) An imide oligomer composition C (imidization rate: 91%) was obtained in the same manner as in Synthesis Example 1, except that the content was changed to 29.2 parts by weight.
By ¹ H-NMR, GPC, and FT-IR analysis, the imide oligomer composition C is an imide oligomer having a structure represented by the above formula (1-1) (A is represented by the above formula (13). It was confirmed that B contains a group represented by the following formula (16). In addition, the number average molecular weight of the imide oligomer composition C was 1,310. Furthermore, the imide oligomer composition C is an imide oligomer represented by the above formula (4-1) as an imide oligomer having a structure represented by the above formula (1-1) (A is represented by the above formula (13) It was confirmed that B contains a group represented by the following formula (16).

In formula (16), * is a binding position.

(Synthesis Example 4 (preparation of imide oligomer composition D))
62.0 parts by weight of 3,4'-oxydiphthalic dianhydride is added to 104.1 parts by weight of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) An imide oligomer composition D (imidization rate 93%) was obtained in the same manner as in Synthesis Example 1 except for the change.
By ¹ H-NMR, GPC, and FT-IR analysis, the imide oligomer composition D was an imide oligomer having a structure represented by the above formula (1-1) (A is represented by the following formula (17). It was confirmed that B contains the group represented by the above formula (14). Also, the number average molecular weight of the imide oligomer having the structure represented by the formula (1-1) was 2,020. Furthermore, the imide oligomer composition D is an imide oligomer represented by the above formula (4-1) as an imide oligomer having a structure represented by the above formula (1-1) (A is represented by the following formula (17) It was confirmed that B contains the group represented by the above formula (14).

In formula (17), * is a binding position.

(Synthesis Example 5 (preparation of imide oligomer composition E))
An imide oligomer composition E (imide conversion rate of 91%) was obtained.
By ¹ H-NMR, GPC, and FT-IR analysis, the imide oligomer composition E was an imide oligomer having a structure represented by the above formula (1-1) (A is represented by the above formula (17). It was confirmed that B contains the group represented by the above formula (14). Also, the number average molecular weight of the imide oligomer having the structure represented by the formula (1-1) was 2,520. Furthermore, the imide oligomer composition E is an imide oligomer represented by the above formula (4-1) as an imide oligomer having a structure represented by the above formula (1-1) (A is represented by the following formula (17) It was confirmed that B contains the group represented by the above formula (14).

(Synthesis Example 6 (preparation of imide oligomer composition F))
An imide oligomer composition F (imidization rate 92%) was obtained in the same manner as in Synthesis Example 1, except that the amount of 3,4'-oxydiphthalic dianhydride added was changed to 65.1 parts by weight.
By ¹ H-NMR, GPC, and FT-IR analysis, the imide oligomer composition F was an imide oligomer having a structure represented by the above formula (1-1) (A is represented by the above formula (13). It was confirmed that B contains the group represented by the above formula (14). Also, the number average molecular weight of the imide oligomer having the structure represented by the formula (1-1) was 1,220. Furthermore, the imide oligomer composition F is an imide oligomer represented by the above formula (4-1) as an imide oligomer having a structure represented by the above formula (1-1) (A is represented by the above formula (13) It was confirmed that B contains the group represented by the above formula (14).

(Synthesis Example 7 (preparation of imide oligomer composition G))
34.5 parts by weight of 1,3-bis(2-(4-aminophenyl)-2-propyl)benzene (manufactured by Mitsui Chemicals Fine Co., Ltd., "Bisaniline M") and N-methylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., "NMP") was dissolved in 400 parts by weight. 62.0 parts by weight of 3,4'-oxydiphthalic dianhydride (manufactured by Tokyo Kasei Kogyo Co., Ltd., "3,4'-ODPA") was added to the resulting solution, and the mixture was stirred at 25°C for 2 hours to react. to obtain an amic acid oligomer solution. The resulting amic acid oligomer solution is heated in N-methylpyrrolidone at 180° C. for 3 hours while removing water generated during imidization with a Dean-Stark tube, and then N-methylpyrrolidone is removed under reduced pressure. Thus, an imide oligomer composition G (imidization rate: 23%) was obtained.
By ¹ H-NMR, GPC, and FT-IR analysis, the imide oligomer composition G was an imide oligomer having a structure represented by the above formula (1-1) (A is represented by the above formula (13). It was confirmed that B contains the group represented by the above formula (14). The number average molecular weight of the imide oligomer having the structure represented by formula (1-1) was 1,400. Furthermore, the imide oligomer composition G is an imide oligomer represented by the above formula (4-1) as an imide oligomer having a structure represented by the above formula (1-1) (A is represented by the above formula (13) It was confirmed that B contains the group represented by the above formula (14).

(Synthesis Example 8 (preparation of imide oligomer composition H))
An imide oligomer composition H (imide conversion rate of 91%) was obtained.
¹ H-NMR, GPC, and FT-IR analysis revealed that the imide oligomer composition H was an imide oligomer having a structure represented by the above formula (1-1) (A is represented by the above formula (17). It was confirmed that B contains the group represented by the above formula (14). Also, the number average molecular weight of the imide oligomer having the structure represented by the formula (1-1) was 4,200.

(Synthesis Example 9 (preparation of imide oligomer composition I))
62.0 parts by weight of 3,4'-oxydiphthalic dianhydride is added to 52.0 parts by weight of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) changed. Further, 34.5 parts by weight of 1,3-bis(2-(4-aminophenyl)-2-propyl)benzene was added to 1,3-bis(3-aminopropyl)tetramethyldisiloxane (manufactured by Tokyo Chemical Industry Co., Ltd. ) was changed to 12.4 parts by weight. An imide oligomer composition I (imidization rate: 90%) was obtained in the same manner as in Synthesis Example 1 except that these changes were made.
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer composition I contained an imide oligomer having a siloxane skeleton and terminal acid anhydride groups. The imide oligomer had a number average molecular weight of 1,880.

(Synthesis Example 10 (preparation of imide oligomer composition J))
24.6 parts by weight of 5-amino-o-cresol was dissolved in 400 parts by weight of N-methylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., "NMP"). 31.0 parts by weight of 3,4'-oxydiphthalic dianhydride (manufactured by Tokyo Kasei Kogyo Co., Ltd., "3,4'-ODPA") was added to the resulting solution, and the mixture was stirred at 25°C for 2 hours to react. to obtain an amic acid oligomer solution. After removing N-methylpyrrolidone from the obtained amic acid oligomer solution under reduced pressure, the solution was heated at 300° C. for 2 hours to obtain an imide oligomer composition J (imidization rate: 91%).
By ¹ H-NMR, GPC, and FT-IR analysis, the imide oligomer composition J was an imide oligomer having a structure represented by the above formula (1-2) (A is represented by the above formula (13). It was confirmed that Ar contains a group represented by the following formula (18). Also, the number average molecular weight of the imide oligomer having the structure represented by the formula (1-2) was 650. Furthermore, the imide oligomer composition J is an imide oligomer represented by the above formula (5-1) as an imide oligomer having a structure represented by the above formula (1-2) (A is represented by the above formula (13) group, R is a methyl group).

In formula (18), * and ** are bonding positions, and * is the bonding position with the hydroxyl group in formula (1-2).

(Synthesis Example 11 (preparation of imide oligomer composition K))
An imide oligomer composition K (imidization rate 90%) was prepared in the same manner as in Synthesis Example 10, except that 24.6 parts by weight of 5-amino-o-cresol was changed to 21.8 parts by weight of 3-aminophenol. Obtained.
By ¹ H-NMR, GPC, and FT-IR analysis, the imide oligomer composition K is an imide oligomer having a structure represented by the above formula (1-2) (A is represented by the above formula (13). It was confirmed that Ar contains a group represented by the following formula (19). Also, the number average molecular weight of the imide oligomer having the structure represented by the formula (1-2) was 630. Furthermore, the imide oligomer composition K is an imide oligomer represented by the above formula (5-1) as an imide oligomer having a structure represented by the above formula (1-2) (A is represented by the above formula (13) group, R is a hydrogen atom).

In formula (19), * is a binding position.

(Synthesis Example 12 (preparation of imide oligomer composition L))
Synthesis example except that 31.0 parts by weight of 3,4'-oxydiphthalic dianhydride was changed to 52.0 parts by weight of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride An imide oligomer composition L (imidization rate 92%) was obtained in the same manner as in 10.
By ¹ H-NMR, GPC, and FT-IR analysis, the imide oligomer composition L was an imide oligomer having a structure represented by the above formula (1-2) (A is represented by the above formula (17). and Ar contains the group represented by the above formula (18). Also, the number average molecular weight of the imide oligomer having the structure represented by the formula (1-2) was 910. Furthermore, the imide oligomer composition L is an imide oligomer represented by the above formula (5-1) as an imide oligomer having a structure represented by the above formula (1-2) (A is the above formula (17) It was confirmed that the represented group, R is a methyl group).

(Synthesis Example 13 (preparation of imide oligomer composition M))
An imide oligomer composition was prepared in the same manner as in Synthesis Example 10, except that 31.0 parts by weight of 3,4′-oxydiphthalic dianhydride was changed to 135.0 parts by weight of the imide oligomer composition E obtained in Synthesis Example 5. Product M (imidization rate 91%) was obtained.
¹ H-NMR, GPC, and FT-IR analysis revealed that the imide oligomer composition M was an imide oligomer having a structure represented by the above formula (1-2) (A is represented by the above formula (17). and Ar contains the group represented by the above formula (18). Also, the number average molecular weight of the imide oligomer having the structure represented by the formula (1-2) was 2,960. Furthermore, the imide oligomer composition M is an imide oligomer represented by the above formula (5-3) as an imide oligomer having a structure represented by the above formula (1-2) (A is represented by the above formula (17) group, B is the group represented by the above formula (14), and R is a methyl group).

(Synthesis Example 14 (preparation of imide oligomer composition N))
An imide oligomer composition N (imidization rate: 91%) was obtained in the same manner as in Synthesis Example 10, except that the amount of 5-amino-o-cresol added was changed to 25.9 parts by weight.
By ¹ H-NMR, GPC, and FT-IR analysis, the imide oligomer composition N was an imide oligomer having a structure represented by the above formula (1-2) (A is represented by the above formula (13). and Ar contains the group represented by the above formula (18). Also, the number average molecular weight of the imide oligomer having the structure represented by the formula (1-2) was 590. Furthermore, the imide oligomer composition N is an imide oligomer represented by the above formula (5-1) as an imide oligomer having a structure represented by the above formula (1-2) (A is represented by the above formula (13) group, R is a methyl group).

(Synthesis Example 15 (preparation of imide oligomer composition O))
24.6 parts by weight of 5-amino-o-cresol was dissolved in 400 parts by weight of N-methylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., "NMP"). 31.0 parts by weight of 3,4'-oxydiphthalic dianhydride (manufactured by Tokyo Kasei Kogyo Co., Ltd., "3,4'-ODPA") was added to the resulting solution, and the mixture was stirred at 25°C for 2 hours to react. to obtain an amic acid oligomer solution. The resulting amic acid oligomer solution is heated in N-methylpyrrolidone at 180° C. for 3 hours while removing water generated during imidization with a Dean-Stark tube, and then N-methylpyrrolidone is removed under reduced pressure. Thus, an imide oligomer composition O (imidization rate: 25%) was obtained.
By ¹ H-NMR, GPC, and FT-IR analysis, the imide oligomer composition O was an imide oligomer having a structure represented by the above formula (1-2) (A is represented by the above formula (13). and Ar contains the group represented by the above formula (18). Also, the number average molecular weight of the imide oligomer having the structure represented by the formula (1-2) was 680. Further, the imide oligomer composition O is an imide oligomer represented by the above formula (5-1) as an imide oligomer having a structure represented by the above formula (1-2) (A is represented by the above formula (13) group, R is a methyl group).

(Synthesis Example 16 (preparation of imide oligomer composition P))
An imide oligomer composition was prepared in the same manner as in Synthesis Example 10, except that 31.0 parts by weight of 3,4′-oxydiphthalic dianhydride was changed to 180.0 parts by weight of the imide oligomer composition H obtained in Synthesis Example 8. Product P (imidization rate 90%) was obtained.
By ¹ H-NMR, GPC, and FT-IR analysis, the imide oligomer composition P was an imide oligomer having a structure represented by the above formula (1-2) (A is represented by the above formula (17) and Ar contains the group represented by the above formula (18). Also, the number average molecular weight of the imide oligomer having the structure represented by the formula (1-2) was 4,610.

(solubility)
Each imide oligomer composition obtained in Synthesis Examples was dissolved in methyl ethyl ketone (MEK), tetrahydrofuran (THF), and bisphenol F-type epoxy resin (manufactured by DIC, "EPICLON EXA-830CRP"). 3 g or more of the imide oligomer composition was dissolved in each 10 g of MEK, THF, and bisphenol F type epoxy resin. Solubility was evaluated as "x" for those that were
For MEK and THF, a predetermined amount of the imide oligomer composition was added to 10 g of MEK or THF, and the mixture was stirred using a planetary stirrer, and the solubility at 25° C. was evaluated. For EXA-830CRP, after adding a predetermined amount of the imide oligomer composition to 10 g of EXA-830CRP, the mixture was stirred for 1 hour while being heated to 150°C, and after cooling, the solubility at 25°C was evaluated.
Table 1 shows the results.

(melting point)
For each imide oligomer composition obtained in Synthesis Examples, the temperature of the endothermic peak when the temperature was raised at 10° C./min using a differential scanning calorimeter ("EXTEAR DSC6100" manufactured by SII Nanotechnology Co., Ltd.) was measured. Measured as melting point.
Table 1 shows the results.

(Examples 1 to 16, Comparative Examples 1 to 5)
According to the compounding ratios shown in Tables 2 to 5, each material was stirred and mixed to prepare curable resin compositions of Examples 1 to 16 and Comparative Examples 1 to 5.
A curable resin composition film was obtained by coating each obtained curable resin composition on a substrate PET film so as to have a thickness of about 20 μm, followed by drying.
The PET film was peeled off from the resulting curable resin composition film, and a polyimide film having a thickness of 50 μm ("Kapton 200H" manufactured by Toray DuPont Co., Ltd.) was applied to both sides of the adhesive layer while heating to 80° C. using a laminator. ) were pasted together. After hot pressing was performed under the conditions of 190° C., 3 MPa, and 1 hour to cure the adhesive layer, a test piece was obtained by cutting into a width of 1 cm. A test piece within 24 hours after preparation was subjected to T-shaped peeling at a peel rate of 20 mm/min at 25° C. using a tensile tester ("UCT-500" manufactured by ORIENTEC) to measure the initial adhesive strength. Also, a test piece prepared in the same manner was stored at 200° C. for 100 hours, then allowed to cool to 25° C., and the adhesive strength of the test piece within 24 hours after cooling was measured in the same manner as the initial adhesive strength described above. .
Furthermore, a test piece prepared in the same manner was stored in an environment of 85 ° C. and 85% RH for 24 hours, then allowed to cool to 25 ° C., and the same initial adhesive strength was obtained for the test piece within 24 hours after cooling. method was used to measure the adhesive force.
In addition, the tack value at 25° C. and the tack value at 60° C. of each curable resin composition film obtained were measured using the surface opposite to the base film. The tack value was measured using a probe tack measuring device (tacking tester TAC-2 (manufactured by RHESCA)), probe diameter 5 mm, contact speed 0.5 mm / sec, test speed 0.5 mm / sec, contact load Measurement was performed under the conditions of 0.05 MPa, contact time of 1 second, and measurement temperatures of 25°C and 60°C.
Furthermore, the surface free energy of each curable resin composition film obtained was measured using the surface opposite to the substrate film. The surface free energy was measured using a contact angle meter to measure the contact angles with water and methylene iodide (dropping amount: 3 μL, 30 seconds after dropping), and calculated using the above formula.
The resulting initial adhesion, adhesion after 100 hours storage at 200°C, adhesion after 24 hours storage at 85°C, 85% RH, tack value at 25°C, tack value at 60°C, and surface The measurement results of free energy are shown in Tables 2-5.

<Evaluation>
Each curable resin composition obtained in Examples and Comparative Examples was evaluated as follows. The results are shown in Tables 2-5.

(Weight reduction rate at 330°C)
A curable resin composition film was obtained by applying each curable resin composition obtained in Examples and Comparative Examples onto a base film and drying the coating.
The obtained curable resin composition film was heated from 30° C. to 400° C. at a rate of 10° C./min using a thermogravimetry device (manufactured by SII Nanotechnology Co., Ltd., “EXTEAR TG/DTA6200”), A weight loss rate (%) at 330°C was measured.

(Glass-transition temperature)
A curable resin composition film was obtained by applying each curable resin composition obtained in Examples and Comparative Examples onto a base film and drying the coating. The obtained curable resin composition films were laminated and cured by heating at 190° C. for 30 minutes to prepare a cured product having a thickness of 400 μm. The resulting cured product was measured using a dynamic viscoelasticity measuring device (manufactured by A&D Co., Ltd., "Leovibron DDV-25GP") at a temperature increase rate of 10 ° C./min, a frequency of 10 Hz, and a distance between chucks of 24 mm to 0 ° C. The peak temperature of the tan δ curve obtained when the temperature was raised from to 300° C. was determined as the glass transition temperature. When the glass transition temperature was 150°C or higher, it was evaluated as "○"; when it was 130°C or more and less than 150°C, it was evaluated as "Δ";

(Long-term heat resistance)
A curable resin composition film was obtained by applying each curable resin composition obtained in Examples and Comparative Examples onto a base film and drying the coating. A 20 μm-thick polyimide film (manufactured by Toray DuPont, “Kapton V”) was laminated on both sides of the resulting 20 μm-thick curable resin composition film, and cured by heating at 190° C. for 1 hour. After that, heat treatment was performed at 175° C. for 1000 hours. The state of the laminate of the curable resin composition film and the polyimide film after the laminate of the curable resin composition film after the heat treatment and the polyimide film is semicircularly aligned with a cylinder having a diameter of 5 mm or 3 mm at room temperature. was visually observed.
"O" indicates that no cracks or cracks were observed when the laminate was semicircularly aligned with a 3 mm cylinder, and no cracks or cracks were observed when the laminate was semicircularly aligned with a 5 mm cylinder. However, "△" indicates that cracks or cracks were observed when the sample was placed along a 3mm cylinder in a semicircular shape, and "X" indicates that cracks or cracks were observed when the sample was placed along a 5mm cylinder in a semicircular shape. Long-term heat resistance was evaluated.

ADVANTAGE OF THE INVENTION According to this invention, it has a high glass transition temperature after hardening, and can provide the curable resin composition which can obtain the hardened|cured material which is excellent in thermal decomposition resistance, adhesiveness, and long-term heat resistance. Further, according to the present invention, a cured product of the curable resin composition, an adhesive containing the curable resin composition, an adhesive film using the curable resin composition, and a circuit having the cured product A substrate can be provided.

Claims (1)

A curable resin, an imide oligomer having an imide skeleton in the main chain, a crosslinkable functional group at the end, and a number average molecular weight of 4000 or less, and a curing accelerator,
The initial adhesive strength of the cured product to polyimide is 3.4 N/cm or more, and the adhesive strength of the cured product to polyimide after storage at 200 ° C. for 100 hours is 0.8 times or more than the initial adhesive strength. A curable resin composition comprising: