JP7400678B2 - Thermosetting compositions, thermosetting sheets, cured products, cured sheets and printed wiring boards - Google Patents

Description

The present invention relates to a thermosetting composition containing a polyimide resin. The present invention also relates to a thermosetting sheet impregnated with a thermosetting composition, a cured sheet thereof, a cured product of the thermosetting composition, and a printed wiring board.

Polyimide resin has excellent heat resistance and chemical resistance, so it is widely used in a wide range of fields including electrical insulation and electronic fields. For example, Patent Document 1 discloses a thermosetting ink composition containing an amic acid having a specific structure, and a method for producing a polyimide film in which the ink composition is applied to form a coating film and then cured. has been done. Furthermore, Patent Documents 2 and 3 disclose polyimide adhesive compositions containing a polyimide resin obtained by reacting aromatic tetracarboxylic acids and dimer diamine with a curing agent such as an epoxy compound. Patent Document 4 describes a polyimide resin containing an aliphatic, alicyclic and/or aromatic tetracarboxylic acid residue and a diamine residue including a dimer diamine, an epoxy resin, and a curing agent capable of curing an epoxy group. A resin composition containing the following is disclosed. Further, Patent Document 5 discloses an adhesive composition comprising a polyimide resin obtained by reacting an aromatic tetracarboxylic acid and a dimer diamine and a dihydrazide curing agent.

Japanese Patent Application Publication No. 2013-032501 Japanese Patent Application Publication No. 2016-191049 Japanese Patent Application Publication No. 2013-199645 Japanese Patent Application Publication No. 2015-117278 JP2020-056011A

The thermosetting ink composition described in Patent Document 1 has the advantage of exhibiting good adhesion to plated copper, but has a problem with storage stability. Further, there is a problem that the high degree of solder heat resistance is inferior. The polyimide adhesive compositions described in Patent Documents 2 and 3 have the advantage of exhibiting good heat-resistant adhesion, but have the problem of poor crack resistance and laser processability. Further, the resin composition described in Patent Document 4 has the advantage of being excellent in solder heat resistance, water absorption, chemical resistance, tensile strength, etc., but has problems in long-term heat resistance and laser processability. Further, the adhesive composition described in Patent Document 5 has the advantage of exhibiting good dielectric properties, but has problems with solder heat resistance, crack resistance, and laser processability.

BACKGROUND ART In multilayer substrate prepregs, buildup films, and interlayer adhesive sheets used in multilayer printed wiring boards and the like, there is a demand for highly reliable resin materials that have excellent adhesive properties with other materials. In addition, there are multiple heating processes during manufacturing, and even after the product is commercialized, it will be used in industrial machinery such as automobiles, ships, and aircraft, so there is a need for highly reliable resin compositions with long-term heat resistance. .

Furthermore, in response to the recent demands for smaller size, lighter weight, and higher density of various substrates, there is a need for thinner and multilayered substrates, and more than ever, improvements in flexibility and crack suppression are required. There is. Further, for example, in a built-up layer, there is a strong desire for a resin material that has excellent laser processability due to the miniaturization of the aperture diameter.

The present invention has been made in view of the above background, and provides a thermosetting composition, a thermosetting sheet, a cured product, and a cured product that can provide a cured product with excellent adhesiveness, long-term heat resistance, crack resistance, and laser processability. Its purpose is to provide sheets and printed wiring boards.

（Ｘ^１は繰り返し単位毎にそれぞれ独立に４価のテトラカルボン酸残基であり、Ｘ^２は繰り返し単位毎にそれぞれ独立に２価のジアミン残基を表し、前記Ｘ^１とイミド結合が互いに結合して２つのイミド環を形成する。）で表される構造の繰り返し単位および酸無水物基の分子鎖末端を含むポリイミド樹脂（Ａ）と、架橋剤（Ｂ）と、を含有する熱硬化性組成物であって、
ポリイミド樹脂（Ａ）中の前記Ｘ^１は、以下の（Ｉ）および（ＩＩ）の少なくとも一方を満たす構造Ｓを有するＸ^１ａを含み、当該Ｘ^１全体を１００モル％としたときに、前記Ｘ^１ａの割合が６０～１００モル％であり、前記Ｘ^２は、ダイマー構造を有するＸ^２ｄを含み、
架橋剤（Ｂ）は、エポキシ化合物（ｂ１）、シアネートエステル化合物(ｂ２)、イソシアネート基含有化合物（ｂ３）、キレート化合物（ｂ４）およびカルボジイミド基含有化合物（ｂ５）からなる群から選択される一種以上である熱硬化性組成物。
（Ｉ）前記イミド環を構成する前記Ｘ^１中の炭素の少なくとも一つが、他方の前記イミド環を構成する前記Ｘ^１中の炭素の少なくとも一つと互いに直結する。
（ＩＩ）２つの前記イミド環それぞれを構成する、前記Ｘ^１中の炭素の少なくとも一つが、それぞれ独立に、脂肪族構造と直結する構造を有する、および構成元素の一つとなる脂肪族構造を含む、のいずれかを満たす。
［２］：エポキシ化合物（ｂ１）として、軟化点が３０～１２０℃のエポキシ化合物を含むことを特徴とする［１］記載の熱硬化性組成物。
［３］：更に、フェノール樹脂（ｄ１）、ベンゾオキサジン（ｄ２）、活性エステル樹脂（ｄ３）およびマレイミド化合物（ｄ４）から選択されるいずれか一種以上である化合物（Ｄ）を含むことを特徴とする［１］または［２］記載の熱硬化性組成物。
［４］：ポリイミド樹脂（Ａ）中の前記Ｘ^２は、当該Ｘ^２全体を１００モル％としたときに、前記Ｘ^２ｄの割合が２０～１００モル％であることを特徴とする［１］～［３］いずれか記載の熱硬化性組成物。
［５］：無機フィラー（Ｃ）を含有することを特徴とする［１］～［４］いずれか記載の熱硬化性組成物。
［６］：１８０℃、６０分の条件で熱硬化した後のガラス転移温度が１４０～２５０℃であることを特徴とする［１］～［５］いずれか記載の熱硬化性組成物。
［７］：ポリイミド樹脂（Ａ）が一般式（２）：

（Ｘ^３は４価のテトラカルボン酸残基を表し、前記Ｘ^３と酸無水物基は互いに結合して酸無水物環を形成し、且つ前記Ｘ^３とイミド結合は互いに結合してイミド環を形成する。）で表される分子鎖末端を有し、ポリイミド樹脂（Ａ）の分子鎖末端中の前記Ｘ^３は、以下の（ＩＩＩ）および（ＩＶ）の少なくとも一方を満たす構造Ｔを有するＸ^３ｔを含む［１］～［６］いずれかに記載の熱硬化性組成物。
（ＩＩＩ）前記酸無水物環を構成する前記Ｘ^３中の炭素の少なくとも一つが、前記イミド環を構成する前記Ｘ^３中の炭素の少なくとも一つと互いに直結する。
（ＩＶ）前記酸無水物環を構成する前記Ｘ^３中の炭素の少なくとも一つ、および前記イミド環を構成する前記Ｘ^３中の炭素の少なくとも一つが、それぞれ独立に脂肪族構造と直結する構造を有する、および構成元素の一つとなる脂肪族構造を含む、のいずれかを満たす。
［８］：［１］～［７］いずれか記載の熱硬化性組成物を繊維基材に含浸させてなる、熱硬化性シート。
［９］：［１］～［７］いずれか記載の熱硬化性組成物を熱硬化させてなる硬化物。
［１０］：［８］記載の熱硬化性シートを熱硬化させてなる、硬化シート。
［１１］：基材上に、［９］記載の硬化物からなる層を有することを特徴とするプリント配線板。
［１２］：［１０］記載の硬化シートを用いてなる、プリント配線板。 As a result of extensive studies, the present inventors have found that the problems of the present invention can be solved in the following embodiments, and have completed the present invention.
[1]: General formula (1):

(X ¹ is a tetravalent tetracarboxylic acid residue independently for each repeating unit, X ² is a divalent diamine residue independently for each repeating unit, and the above X ¹ and imide bond are bonded to each other. to form two imide rings.) A thermosetting resin containing a polyimide resin (A) containing a repeating unit with a structure represented by (A) and a molecular chain end of an acid anhydride group, and a crosslinking agent (B). A composition,
The above-mentioned X ¹ in the polyimide resin (A) includes X ¹ a having a structure S satisfying at least one of the following (I) and (II), and when the entire X ¹ is taken as 100 mol%, the above-mentioned The proportion of X ¹ a is 60 to 100 mol%, and the X ² includes X ² d having a dimer structure,
The crosslinking agent (B) is one or more selected from the group consisting of an epoxy compound (b1), a cyanate ester compound (b2), an isocyanate group-containing compound (b3), a chelate compound (b4), and a carbodiimide group-containing compound (b5). A thermosetting composition.
(I) At least one carbon in X ¹ constituting the imide ring is directly bonded to at least one carbon in X ¹ constituting the other imide ring.
(II) At least one of the carbons in X ¹ constituting each of the two imide rings each independently has a structure that is directly connected to an aliphatic structure, and contains an aliphatic structure that is one of the constituent elements. , satisfies either of the following.
[2]: The thermosetting composition according to [1], characterized in that the epoxy compound (b1) contains an epoxy compound having a softening point of 30 to 120°C.
[3]: Further comprising a compound (D) which is one or more selected from phenol resin (d1), benzoxazine (d2), active ester resin (d3) and maleimide compound (d4). The thermosetting composition according to [1] or [2].
[4]: The above-mentioned X ² in the polyimide resin (A) is characterized in that the proportion of the above-mentioned X ² d is 20 to 100 mol% when the entire X ² is 100 mol% [1 ] to [3] The thermosetting composition according to any one of the above.
[5]: The thermosetting composition according to any one of [1] to [4], which contains an inorganic filler (C).
[6]: The thermosetting composition according to any one of [1] to [5], which has a glass transition temperature of 140 to 250°C after thermosetting at 180°C for 60 minutes.
[7]: Polyimide resin (A) has general formula (2):

(X ³ represents a tetravalent tetracarboxylic acid residue, X ³ and the acid anhydride group are bonded to each other to form an acid anhydride ring, and X ³ and the imide bond are bonded to each other to form an imide ring. ), and the X ³ in the molecular chain end of the polyimide resin (A) has a structure T that satisfies at least one of the following (III) and (IV). The thermosetting composition according to any one of [1] to [6], which contains X ³ t.
(III) At least one of the carbon atoms in X ³ constituting the acid anhydride ring is directly bonded to at least one carbon in X ³ constituting the imide ring.
(IV) A structure in which at least one of the carbons in X ³ constituting the acid anhydride ring and at least one carbon in X ³ constituting the imide ring are each independently directly connected to an aliphatic structure. and contains an aliphatic structure that is one of the constituent elements.
[8]: A thermosetting sheet obtained by impregnating a fiber base material with the thermosetting composition according to any one of [1] to [7].
[9]: A cured product obtained by thermosetting the thermosetting composition according to any one of [1] to [7].
[10]: A cured sheet obtained by thermosetting the thermosetting sheet described in [8].
[11]: A printed wiring board characterized by having a layer made of the cured product described in [9] on a base material.
[12]: A printed wiring board using the cured sheet described in [10].

According to the present invention, it is possible to provide a thermosetting composition, a thermosetting sheet, a cured product, a cured sheet, and a printed wiring board from which a cured product with excellent adhesiveness, long-term heat resistance, crack resistance, and laser processability can be obtained. It has excellent effects.

The present invention will be explained in detail below. It goes without saying that other embodiments are also included in the scope of the present invention as long as they meet the spirit of the present invention. Furthermore, in this specification, numerical ranges specified using "~" include the numerical values written before and after "~" as the lower limit and upper limit ranges. Furthermore, in this specification, "film" and "sheet" are not distinguished by thickness. In other words, the term "sheet" in this specification includes a thin film, and the term "film" in this specification includes a thick sheet. Further, unless otherwise noted, the various components appearing in this specification may be used individually or in combination of two or more.

In the present specification, "Mw" and "Mn" are a weight average molecular weight and a number average molecular weight in terms of polystyrene, which are determined by gel permeation chromatography (GPC) measurement. These can be measured by the method described in the [Example] section.

[[Thermosetting composition]]
The thermosetting composition according to this embodiment is a composition containing at least a polyimide resin (A) and a crosslinking agent (B), which will be described later. Here, the thermosetting composition refers to a composition containing a thermosetting resin, and refers to a composition that is cured by forming a three-dimensional crosslinked structure of the resin by heat curing treatment. Note that in this specification, a cured product refers to a state that has been cured to such an extent that the curing reaction does not substantially proceed even if it is further heated. When a thermosetting composition is molded into a desired shape such as a sheet, a part of it may undergo a curing reaction, but a state in which it can be cured by further heating is not included in the term cured product. At the stage of the thermosetting composition, some of the components may be in a semi-cured B-stage state.

According to the thermosetting composition according to the present embodiment, a polyimide resin (A) containing a repeating unit represented by general formula (1) described below and a molecular chain terminal of an acid anhydride group, and a specific compound described below. A crosslinking agent ( ^B ) selected from By including X ² d having the following, a thermosetting composition whose cured product has excellent adhesiveness and heat resistance can be obtained. Moreover, the cured product has excellent long-term heat resistance, crack resistance, and laser processability. Hereinafter, each component and manufacturing method of the thermosetting composition of this embodiment will be explained in detail.

式（１）中のＸ^１は繰り返し単位毎にそれぞれ独立に４価のテトラカルボン酸残基であり、Ｘ^２は繰り返し単位毎にそれぞれ独立に２価のジアミン残基を表す。Ｘ^１とイミド結合は互いに結合して２つのイミド環を形成する。 [Polyimide resin (A)]
The polyimide resin (A) according to the present embodiment is a resin containing a repeating unit having a structure represented by the following general formula (1) and a molecular chain terminal of an acid anhydride group.

In formula (1), X ¹ represents a tetravalent tetracarboxylic acid residue independently for each repeating unit, and X ² represents a divalent diamine residue independently for each repeating unit. X ¹ and the imide bond combine with each other to form two imide rings.

The X ¹ in the polyimide resin (A) includes X ¹ a having a structure S satisfying at least one of the following (I) and (II). Further, the X ² includes X ² d having a dimer structure.
(I) At least one carbon in X ¹ constituting an imide ring is directly bonded to at least one carbon in X ¹ constituting the other imide ring.
(II) At least one of the carbons in X ¹ constituting each of the two imide rings each independently has a structure that is directly connected to an aliphatic structure, and contains an aliphatic structure that is one of the constituent elements. Satisfy either.
When the total amount of X ¹ constituting the polyimide resin (A) is 100 mol %, the proportion of X ¹ a having structure S is 60 to 100 mol %.

As used herein, "tetracarboxylic acid residue" refers to components derived from tetracarboxylic acid and tetracarboxylic acid derivatives such as tetracarboxylic dianhydride and tetracarboxylic acid diester, and "diamine residue" refers to a component derived from diamine. Furthermore, an "imide bond" is defined as one nitrogen atom and two carbonyl bonds (C=O), and the imide bond and a portion of ^X1 in formula (1) bond to each other to form an imide ring. Form. "Imide ring" is a ring having an imide bond, and the number of elements forming one ring is 4 or more and 7 or less. Preferably it is 5 or 6. The imide ring may be fused with another ring. In addition, "acid anhydride group" means a group represented by -C(=O)-OC(=O)-, and "acid anhydride ring" refers to an acid anhydride group and a carbon element. A ring formed by bonding.

The "aliphatic structure" includes a chain hydrocarbon structure and/or an alicyclic hydrocarbon structure that may contain a substituent. A "chain hydrocarbon structure" is a linear hydrocarbon structure and/or a branched hydrocarbon structure that may have an unsaturated bond. Moreover, the "alicyclic hydrocarbon structure" is an alicyclic hydrocarbon that may have an unsaturated bond, and may be monocyclic or polycyclic. Examples of the substituents include alkyl groups, halogens, carbonyl groups, and the like.

Specific examples of X ¹ a having structure S that satisfy the above (I) include chemical formulas (Ia) to (Id). Note that chemical formulas (I-b) to (I-d) are also compounds that satisfy the above (II). * in the formula indicates a bonding site with an imide group.

Specific examples of X ¹ a having the structure S that satisfy the above (II) include chemical formulas (II-a) to (II-v).

As an example of X ¹ a having a structure S in which carbon in X ¹ forming an imide ring is directly connected to a chain hydrocarbon structure which is an aliphatic structure, a compound represented by chemical formula (II-a) can be exemplified. . As an example of X ¹ a in which the carbon in X 1 forming the imide ring has a structure S containing an alicyclic hydrocarbon structure of the ^aliphatic structure serving as one of the constituent elements, chemical formula (II-b) is used. The compounds represented can be exemplified. Furthermore, the carbon in X ¹ forming one imide ring is directly connected to the alicyclic hydrocarbon structure of the aliphatic structure, and the carbon in X ¹ forming the other imide ring is connected to one of the constituent elements. As an example of X ¹ a having a structure S including an alicyclic hydrocarbon structure among the aliphatic structures, chemical formula (II-c) can be exemplified. Note that it is sufficient that the two imide rings each independently satisfy at least one of the above (I) and (II), and may contain an aromatic ring as shown in chemical formula (II-d).

The "dimer structure" is a structure derived from a fatty acid dimer (hereinafter referred to as a fatty acid dimer), and includes X ² d having a dimer structure as X ² in general formula (1). X ² d is a diamine residue derived from dimer diamine. As the dimer diamine, a compound obtained by converting the carboxyl group of dimer acid into an amino group can be used. Examples of the conversion method include a method in which a carboxylic acid is amidated, aminated by Hoffmann rearrangement, and further distilled and purified. Note that the dimer acid is a polybasic acid having a dimer structure, and is a fatty acid dimer. Specific examples of dimer diamine will be described later.

The proportion of X ¹ a having structure ^S is the proportion of It can be determined from the content (mol %) of monomers in which ^1a is a residue. Similarly, the proportion of X ² d having a dimer structure is determined based on the proportion of X 2 d having a dimer structure in 100 mol% of the total monomers forming the X ² residue among the raw material monomers used when synthesizing the polyimide resin (A). It can be determined from the content (mol%) of monomers in which X ² d is a residue.

The proportion of X ^{1 a} having structure S is 60 to 100 mol%, more preferably 70 to 100 mol%, and more preferably The preferred range is 80 to 100 mol%. Further, the proportion of X ² d having the dimer structure is preferably 20 to 100 mol%, and more preferably 40 to 100 mol%, when the total amount of X ² constituting the polyimide resin (A) is 100 mol%. The more preferable range is 60 to 100 mol%.

The dimer structure has multiple hydrocarbon chains and ring structures, and there is little interaction between molecular chains. By including the dimer structure in the polyimide resin (A), the resin composition It is possible to alleviate the internal stress generated within the structure. Stress relaxation due to the dimer structure contained in the polyimide resin (A) can suppress a decrease in adhesive strength and the occurrence of cracks caused by stress caused by repeated high and low temperatures.

Note that the polyimide resin (A) may contain residues derived from monomers other than the X ¹ residue and the X ² residue without departing from the spirit of the present invention.

The method of introducing an acid anhydride group to the molecular chain end of the polyimide resin (A) is not particularly limited. An example of a simple method is a method in which the polymerizable functional groups of monomer Y1 constituting the ^X1 residue are blended in a larger amount than the polymerizable functional groups of monomer Y2 constituting the ^X2 residue. In addition, the monomers Y1 and Y2 may be used alone or in combination of two or more. Depending on the desired weight average molecular weight, for example, the equivalent ratio of the polymerizable functional group of monomer Y1/the polymerizable functional group of monomer Y2 can be adjusted within a range of more than 1.0 and 5.0 or less. . More preferably 1.01 to 3.0, still more preferably 1.02 to 2.0. Instead of the above method, after producing a polyimide precursor in which the equivalent ratio of the polymerizable functional group of monomer Y1/the polymerizable functional group of monomer Y2 is 1 or less than 1, the terminal is capped to An acid anhydride group may also be introduced.

式（２）中のＸ^３は４価のテトラカルボン酸残基を表し、Ｘ^３と酸無水物基は互いに結合して酸無水物環を形成し、且つＸ^３とイミド結合は互いに結合してイミド環を形成する。 It is more preferable that the acid anhydride group at the molecular chain end includes a molecular chain end represented by general formula (2).

In formula (2), X ³ represents a tetravalent tetracarboxylic acid residue, X ³ and an acid anhydride group are bonded to each other to form an acid anhydride ring, and X ³ and an imide bond are bonded to each other. to form an imide ring.

X ³ in the molecular chain terminal of the polyimide resin (A) includes X ³ t having a structure T that satisfies at least one of the following (III) and (IV).
(III) At least one of the carbon atoms in X ³ constituting the acid anhydride ring is directly bonded to at least one carbon in X ³ constituting the imide ring.
(IV) At least one carbon in X ³ constituting the acid anhydride ring and at least one carbon in X ³ constituting the imide ring each independently have a structure directly connected to an aliphatic structure. , and contains an aliphatic structure that is one of the constituent elements,
It has a structure that satisfies either of the following.
By having such a structure, the packing property of the polyimide resin (A) can be suppressed and flexibility can be imparted more effectively.

Preferred examples of X ³ include the compounds listed in (I-a) to (I-d) and (II-a) to (II-v) above.

The polyimide resin (A) can include a molecular chain terminal having no functional group. For example, the number of functional groups can be reduced by sealing a portion of the anhydride group at the end of the molecular chain with a monoamine compound. According to this method, the amount of acid anhydride groups at the molecular chain terminals of the polyimide resin (A) can be easily adjusted. Note that the molecular chain terminal of the polyimide resin (A) may have a functional group other than an acid anhydride group without departing from the spirit of the present invention.

(Mw of polyimide resin (A))
The weight average molecular weight of the polyimide resin (A) is preferably within the range of 3,000 to 200,000, more preferably within the range of 4,000 to 150,000, and preferably within the range of 5,000 to 100,000. More preferred. If the weight average molecular weight is 3,000 or more, the resulting cured product will have good crack resistance. On the other hand, if it is 200,000 or less, the laser processability of the cured product will be good. Note that the weight average molecular weight is a polystyrene equivalent weight average molecular weight determined by gel permeation chromatography (GPC) measurement.

(Tg of polyimide resin (A))
The glass transition temperature of the polyimide resin (A) is preferably 0°C to 90°C, more preferably 10°C to 70°C, even more preferably 20°C to 60°C. The glass transition temperature is the temperature at which the value obtained by dividing the viscosity term by the elastic term (tan δ) of a cured resin composition measured with a dynamic viscoelasticity measurement device is at its maximum.
If the glass transition temperature is 0°C or higher, it is easier to obtain a uniform resin composition in the step of blending other components such as a crosslinking agent (B) and an inorganic filler such as silica (C) with the polyimide resin (A). . On the other hand, if the glass transition temperature is 90°C or lower, when a resin composition containing polyimide resin (A) is molded into a sheet, blocking between the sheet-shaped resin compositions is unlikely to occur, resulting in problems in handling. It is difficult to become

As a result of intensive studies by the present inventors, it ^was found that The ratio is 60 to 100 mol% when the entire component constituting X ¹ is 100 mol%, and by including X ² d having a dimer structure as X ² , it has excellent adhesiveness and heat resistance, Furthermore, it was found that not only was the material excellent in long-term heat resistance, but also crack resistance and laser processability were significantly superior.

The reason for this is not clear, but by introducing X ¹ a with the structure S and X ² d with the dimeric structure, and the ring structure with the acid anhydride group at the end of the molecular chain, the packing around the highly planar imide ring is improved. It is thought that the synergistic effect of increasing the interaction between the molecular chain end and the imide ring while simultaneously inhibiting the properties of the imide ring made it possible to increase the flexibility, resulting in a marked increase in crack resistance. In addition, the presence of an acid anhydride group at the end of the molecular chain further promotes suppression of packing around the imide ring of the polyimide resin (A), promoting uniform dispersion of the imide ring, and localizing the area around the imide group during laser processing. It is thought that this makes it possible to suppress heating, making it possible to miniaturize the opening diameter during laser processing.

<Method for producing polyimide resin (A)>
Polyimide resin (A) can be produced by various known methods. A specific example is a method in which a polyamic acid resin or a polyamic acid ester resin, which is a polyimide precursor, is cyclized by heating and converted into an imide group. A method for synthesizing polyamic acid resin includes, for example, a method in which tetracarboxylic dianhydride and diamine are reacted. More specifically, a monomer containing a tetracarboxylic dianhydride and a diamine is dissolved in a solvent, stirred for 0.1 to 2 hours at a temperature of 60 to 120°C, and polymerized to form a polyimide precursor. A polyamic acid resin can be produced.

Synthesis methods for polyamic acid ester resins include obtaining a diester using tetracarboxylic dianhydride and alcohol and then reacting it with diamine in the presence of a condensing agent, or obtaining a diester using tetracarboxylic dianhydride and alcohol. An example of this is a method in which the remaining dicarboxylic acid is then converted into acid chloride and reacted with a diamine.

Examples of organic solvents used in polymerization include N-methyl-2-pyrrolidone (NMP), 2-butanone, dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMAc). ), N,N-diethylacetamide, hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme, and cresol. The solvents may be used alone or in combination of two or more. It is also possible to use aromatic hydrocarbons such as xylene and toluene in combination.

The method of imidizing a polyimide precursor to obtain a polyimide resin is not particularly limited, but an example is a method of heating in a solvent at a temperature of 80 to 400° C. for 0.5 to 50 hours. At this time, a catalyst and/or a dehydrating agent may be used if necessary.

Examples of the reaction catalyst include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, and heterocyclic tertiary amines such as pyridine, picoline, and isoquinoline. Examples of the dehydrating agent include aliphatic acid anhydrides such as acetic anhydride and aromatic acid anhydrides such as benzoic anhydride.

The imidization rate (formation rate of imide rings) is not limited, but from the viewpoint of effectively exhibiting the effect of long-term heat resistance, it is preferably 80% or more, more preferably 90% or more, and 95% or more. More preferably, it is 100%. The imidization rate can be determined by NMR or IR analysis.

(Tetracarboxylic dianhydride having structure S)
The tetracarboxylic dianhydride that becomes the monomer of X 1 a having structure S in X ¹ in general formula ( ¹ ) is particularly limited as long as it satisfies at least either of the above (I) or (II). Not done.
Specific examples include 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-pentanetetracarboxylic acid, 1,2,4,5-pentanetetracarboxylic acid, 1,2,3,4 -Hexanetetracarboxylic acid, 1,2,5,6-hexanetetracarboxylic acid, and other tetracarboxylic dianhydrides having a chain hydrocarbon structure can be exemplified.

Also, cyclobutane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, cyclohexane-1,2,3,4-tetracarboxylic acid, cyclohexane-1,2 , 4,5-tetracarboxylic acid, 1-carboxymethyl-2,3,5-cyclopentanetricarboxylic acid, 3-carboxymethyl-1,2,4-cyclopentanetricarboxylic acid, rel-dicyclohexyl-3,3', 4,4'-tetracarboxylic acid, tricyclo[4.2.2.02,5]dec-9-ene-3,4,7,8-tetracarboxylic acid, 5-carboxymethylbicyclo[2.2.1 ] heptane-2,3,6-tricarboxylic acid, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic acid, bicyclo[2.2.2]oct-7-ene-2, 3,6,7-tetracarboxylic acid, bicyclo[3.3.0]octane-2,4,6,7-tetracarboxylic acid, 7,8-diphenylbicyclo[2.2.2]oct-7-ene -2,3,5,6-tetracarboxylic acid, 4,8-diphenyl-1,5-diazabicyclooctane-2,3,6,7-tetracarboxylic acid, 9-oxatricyclo[4.2. 1.02,5]nonane-3,4,7,8-tetracarboxylic acid, 9,14-dioxopentacyclo[8.2.11,11.14,7.02,10.03,8]tetradecane Cyclo, bicyclo, tricyclotetracarboxylic acids such as -5,6,12,13-tetracarboxylic acid; spiro ring-containing such as 2,8-dioxaspiro[4.5]decane-1,3,7,9-teloton Tetracarboxylic acid; fats such as 1,3,3a,4,5,9b-hexahydro-5(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-c]furan-1,3-dione Examples include tetracarboxylic dianhydrides having a cyclic hydrocarbon structure.

式中のＸ^５は、２価の置換基を有していてもよい有機基（例えば炭素数１～１０の炭化水素基）、－Ｏ－、－ＣＯ－、－ＳＯ_２－、－Ｓ－、－ＳＯ_２－、－ＣＯＮＨ－、－ＣＯＯ－、又は－ＯＣＯ－等の連結基を示す。 (Tetracarboxylic dianhydride without structure S)
In X ¹ in general formula (1), as a monomer other than the monomer of X ¹ a having structure S, that is, as a tetracarboxylic dianhydride that becomes a monomer of X ¹ not having structure S Examples include compounds in which an imide ring and an aromatic group are directly connected or form a polycyclic structure. Specific examples include pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6, Examples of anhydrides include 7-naphthalenetetracarboxylic dianhydride and diphthalic acid represented by the following general formula (4).

In the formula, X ⁵ is an organic group that may have a divalent substituent (for example, a hydrocarbon group having 1 to 10 carbon atoms), -O-, -CO-, -SO ₂ -, -S- , -SO ₂ -, -CONH-, -COO-, or -OCO-.

The tetracarboxylic dianhydride having structure S and the tetracarboxylic dianhydride not having structure S may be used independently, or two or more types may be used in combination. Moreover, the above monomer examples may have a substituent as appropriate. Examples of the substituent include an alkyl group, a halogen atom, a nitro group, and a cyano group. Further, in place of the above-mentioned tetracarboxylic dianhydride, a tetracarboxylic acid having a similar structure or a tetracarboxylic acid derivative such as a tetracarboxylic acid diester may be used.

(Dimer diamine with dimer structure)
As the dimer diamine which becomes the monomer of X ² d having a dimer structure in X ² in the general formula (1), a compound obtained by converting the carboxyl group of a dimer acid into an amino group can be used as described above. Dimer acid is a polybasic acid having a dimer structure, and is a fatty acid dimer (fatty acid dimer). The fatty acid dimer is preferably a compound having 20 to 60 carbon atoms, more preferably a compound having 24 to 56 carbon atoms, even more preferably a compound having 28 to 48 carbon atoms, and even more preferably a compound having 36 to 44 carbon atoms. The fatty acid dimer is preferably a dicarboxylic acid compound having a branched structure obtained by subjecting a fatty acid to a Diels-Alder reaction. The branched structure preferably has an aliphatic chain and a ring structure, and more preferably a ring structure. The ring structure preferably has one or more aromatic rings or an alicyclic structure, and more preferably an alicyclic structure. When an alicyclic structure has one double bond in the ring, it may not have a double bond.

The dimer diamine is preferably a compound having 20 to 60 carbon atoms, more preferably a compound having 24 to 56 carbon atoms, even more preferably a compound having 28 to 48 carbon atoms, and even more preferably a compound having 36 to 44 carbon atoms. A dimer diamine having such a carbon number is preferable from the viewpoint of easy availability.

Commercial products of dimer diamine include, for example, "Priamine 1071", "Priamine 1073", "Priamine 1074", and "Priamine 1075" manufactured by Croda Japan, and "Versamine 551" manufactured by BASF Japan. Dimer diamines can be used alone or in combination of two or more types.

Note that polybasic acids having a dimer structure for obtaining dimer diamine include, for example, structures shown by the following chemical formulas (d1) to (d4). Note that it goes without saying that the polybasic acid having a dimer structure is not limited to the following structure.

(Other diamines without dimer structure)
In X ² in general formula (1), a monomer other than the monomer forming the X ² d residue having a dimeric structure, i.e., other diamine that becomes a monomer of X ² without a dimeric structure is not particularly limited. Specifically, aliphatic structures that may have substituents (chain hydrocarbon structures and/or alicyclic hydrocarbon structures that may contain unsaturated bonds), aromatic rings, and There are diamine compounds that have arbitrary combinations of. When a diamine having a phenolic hydroxyl group is used as the other diamine, the phenolic hydroxyl group can be introduced into the polyimide resin (A). By using the polyimide resin (A) having a phenolic hydroxyl group, the crosslinking point with the crosslinking agent (B) can be adjusted and the three-dimensional crosslinked structure can be adjusted, so a tough cured product can be obtained.

Other diamines include, for example, 1,4-diaminobenzene, 1,3-diaminobenzene, 1,2-diaminobenzene, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3-diaminonaphthalene, 2 , 6-diaminotoluene, 2,4-diaminotoluene, 3,4-diaminotoluene, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diamino -1,2-diphenylethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 3 , 3'-diaminodiphenylsulfone; ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,9-nonanediamine, 1 , 12-dodecamethylene diamine, metaxylene diamine and other aliphatic diamines; isophorone diamine, norbornane diamine, 1,2-cyclohexane diamine, 1,3-cyclohexane diamine, 1,4-cyclohexane diamine, 4,4'-diaminodicyclohexyl Examples include alicyclic diamines such as methane and piperazine.

A diaminophenol compound is a phenol having two amino groups. Examples of diaminophenols include diamines represented by the following general formula (5).

In the formula, R ¹ represents a direct bond or a group containing carbon, hydrogen, oxygen, nitrogen, sulfur, or halogen. The group is, for example, a divalent hydrocarbon group having 1 to 30 carbon atoms, a divalent hydrocarbon group having 1 to 30 carbon atoms in which part or all of the hydrogen atoms are substituted with halogen atoms, -(C= O)-, -SO ₂ -, -O-, -S-, -NH-(C=O)-, -(C=O)-O-, a group represented by the following general formula (6) and the following Examples include groups represented by general formula (7). In the formula, r and s each independently represent an integer of 1 to 20, and R ² represents a hydrogen atom or a methyl group.

Examples of diamines represented by general formula (5) include 2,2-bis(3-amino-4-hydroxyphenyl)propane, 9,9-bis(3-amino-4-hydroxyphenyl)fluorene, and 2,2-bis(3-amino-4-hydroxyphenyl)fluorene. Examples include (3-amino-4-hydroxyphenyl)hexafluoropropane 4,4'-diamino-3,3'-dihydroxybisphenyl.

Among these, as other diamines, isophorone diamine or norbornane diamine is preferable from the viewpoint of further improving adhesive strength and heat cycle property.

(Other monomers)
Monomers other than those mentioned above may be used without departing from the spirit of the invention. For example, a polyamine compound having three or more amino groups may be used. Examples of the polyamine compound having three or more amino groups include 1,2,4-triaminobenzene and 3,4,4'-triamino diphenyl ether.

[Crosslinking agent (B)]
"Crosslinking agent (B)" refers to a compound that has two or more reactive functional groups in one molecule and can construct a crosslinked structure. The crosslinking agent (B) is one or more selected from the group consisting of an epoxy compound (b1), a cyanate ester compound (b2), an isocyanate group-containing compound (b3), a chelate compound (b4), and a carbodiimide group-containing compound (b5). shall be. The crosslinking agent (B) may be a low molecular compound or a high molecular compound.

The crosslinking agent (B) may be a compound that itself exhibits thermosetting properties, or may be a compound in which the crosslinking agent (B) and the polyimide resin (A) are crosslinked. Further, the crosslinking agent (B) and the later-described compound (D) may be a compound that crosslinks. These may be combined arbitrarily.

<Epoxy compound (b1)>
The epoxy compound (b1) refers to a compound having two or more epoxy groups in one molecule, and known compounds can be used. From the viewpoint of increasing heat resistance more effectively, an epoxy compound (b1) having an Mw of 200 to 3000 is more preferable.

Examples of the epoxy compound (b1) include an epoxy compound (b1-1) which is liquid at room temperature of 25°C, and an epoxy compound (b1-2) whose softening point exceeds 25°C and is below 160°C. The softening point of (b1-2) is more preferably 30 to 150°C, even more preferably 30 to 120°C. The softening point is the temperature at which the epoxy compound that is the resin softens, and is a value measured by the softening point test (ring and ball method) (measurement conditions: in accordance with JIS-2817).

Examples of the epoxy compound (b1-1) include bisphenol A epoxy resin, bisphenol F epoxy resin, biphenyl epoxy resin, novolac epoxy resin, dicyclopentadiene epoxy resin, polyfunctional phenol epoxy resin, and naphthalene epoxy resin. Examples include epoxy resins, aralkyl-modified epoxy resins, alicyclic and alcohol-based glycidyl ethers, alicyclic and alcohol-based glycidyl amines, and alicyclic and alcohol-based glycidyl ester resins. It will be done.

Examples of the epoxy compound (b1-2) include bisphenol epoxy resins such as bisphenol A epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin; novolac epoxy resins such as o-cresol novolak epoxy resin; Biphenyl type epoxy resin, naphthalene type epoxy resin, naphthalene-containing novolak type epoxy resin, dicyclopentadiene type epoxy resin, phenol aralkyl type epoxy resin, trisphenolmethane type epoxy resin, phenol-modified xylene resin type epoxy resin, chemical formula (5) described below. ) to (10) can be mentioned.

Among these, biphenylaralkyl epoxy resins, biphenyl epoxy resins, triphenolmethane epoxy resins, and xylene structure-containing novolak epoxy resins are preferred from the viewpoint of further improving crack resistance and laser processability.

Suitable examples include epoxy resins of the following chemical formulas (b1-2-1) to (b1-2-6). n in the formula is an integer, preferably from 1 to 10, for example.

By using the epoxy compound (b1-2) with a softening point of 30 to 120°C, adhesiveness and heat resistance can be more effectively exhibited. Further, the combined use of the epoxy compound (b1-2) and the epoxy compound (b1-1) having a softening point of 30 to 120°C is excellent in terms of improving adhesiveness.

The epoxy equivalent of the epoxy compound (b1) is 100 to 300 g/eq. is preferably 150 to 250 g/eq. is more preferable. Further, the content ratio (mass ratio) of the polyimide resin (A) and the epoxy compound (b1) is preferably (A):(b1) = 5:95 to 50:50, and 10:90 to 30:70. is more preferable. By setting the above ratio, crack resistance and laser processability can be further improved.

The epoxy compound (b1) can be used alone or in combination of two or more. By using two or more kinds, adhesiveness and soldering heat resistance can be improved more suitably.
For example, it is preferable to include a biphenylaralkyl epoxy resin and a novolak epoxy resin containing a xylene structure, or a biphenylaralkyl epoxy resin and a trisphenolmethane epoxy resin. Among these, when a biphenylaralkyl epoxy resin and a novolak epoxy resin containing a xylene structure, or a biphenylaralkyl epoxy resin and a trisphenolmethane epoxy resin are used in combination at a mass ratio of 2:8 to 8:2, a polyimide resin can be obtained. It is preferable because it has appropriate compatibility with (A) and further improves soldering heat resistance.

<Cyanate ester compound (b2)>
"Cyanate ester compound (b2)" refers to a compound in which the average number of cyanate groups per molecule (average number of cyanate groups) is 2 or more, and specific examples include 2,2-bis(4-cyanatophenyl) Aromatic cyanate ester compounds such as propane (bisphenol A type cyanate resin), bis(3,5-dimethyl-4-cyanatophenyl)methane, 2,2-bis(4-cyanatophenyl)ethane, etc. or derivatives thereof Can be mentioned. These may be used alone or in combination of two or more.

<Isocyanate group-containing compound (b3)>
The "isocyanate group-containing compound (b3)" is not particularly limited as long as it has two or more isocyanate groups per molecule, but specific examples include aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, etc. Examples include polyisocyanates. The isocyanate group-containing compounds can be used alone or in combination of two or more.

Examples of aromatic polyisocyanates include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate ( MDI), 2,4-diphenylmethane diisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-di Examples include isocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, 4,4',4''-triphenylmethane triisocyanate, m-isocyanatophenylsulfonyl isocyanate, p-isocyanatophenylsulfonyl isocyanate.

Examples of aliphatic polyisocyanates include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate. , 2,6-diisocyanatomethyl caproate, bis(2-isocyanatoethyl) fumarate, bis(2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate, etc. Can be mentioned.

Examples of the alicyclic polyisocyanate include isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H12-MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), and bis(2-isocyanato). Examples include ethyl)-4-cyclohexene-1,2-dicarboxylate, 2,5-norbornane diisocyanate, and 2,6-norbornane diisocyanate.

Further examples include a trimethylolpropane adduct of diisocyanate, a burette reacted with water, and a trimer having an isocyanurate ring.

The blocked isocyanate compound is not particularly limited as long as it is a blocked isocyanate group-containing compound in which the isocyanate group is protected with ε-caprolactam, MEK oxime, or the like. Specifically, examples include compounds in which the isocyanate group of the isocyanate group-containing compound is blocked with ε-caprolactam, MEK oxime, cyclohexanone oxime, pyrazole, phenol, and the like. In particular, when used in this embodiment, hexamethylene diisocyanate trimer having an isocyanurate ring and blocked with MEK oxime or pyrazole not only has good storage stability but also can be used in resin layers such as polyimide base materials and copper It is very preferable because it has excellent adhesive strength to bonding materials such as metal layers and soldering heat resistance.

<Chelate compound (b4)>
"Chelate compound (b4)" refers to a complex formed by coordination of a multidentate ligand (chelate ligand) to a metal ion, and refers to a compound having at least two crosslinking groups with an acid anhydride group. say. Specific examples include aluminum chelate compounds, titanium chelate compounds, and zirconium chelate compounds, but are not particularly limited because chelate bonds can be formed with various metals such as iron, cobalt, and indium as the central metal.

<Carbodiimide group-containing compound (b5)>
"Carbodiimide group-containing compound (b5)" refers to a compound having at least two or more carbodiimide groups in the molecule, and specific examples include Carbodilite series manufactured by Nisshinbo Co., Ltd. Among them, carbodilite V-01, 03, 05, 07, and 09 are preferred because they have excellent compatibility with organic solvents.

[Inorganic filler (C)]
The thermosetting composition may contain an inorganic filler (C) as an optional component. The type of inorganic filler (C) can be used alone or in combination of two or more depending on the desired properties such as flame retardancy, mechanical strength, heat resistance, thermal conductivity, and hygroscopicity. . Specific examples include calcium carbonate, aluminum oxide, magnesium oxide, aluminum nitride, boron nitride, silicon nitride, titanium oxide, zinc oxide, talc, calcium carbonate, carbon black, silica, copper powder, aluminum powder, and silver powder. can.

By containing silica filler as the inorganic filler (C), crack resistance and laser processability can be improved. Specific examples of the silica filler include silica fillers such as fused crushed silica, fused spherical silica, crystalline silica, and secondary agglomerated silica.

The average particle diameter D ₅₀ of the silica filler is preferably 0.2 to 100 μm, and considering the balance between softness, flexibility, and high filling, it is preferably 1 to 50 μm, more preferably 5 to 30 μm, and even more preferably 10 to 22 μm. . In this embodiment, the average particle diameter D ₅₀ is a value measured using a laser diffraction scattering particle size distribution measuring device using a sample arbitrarily extracted from the population.

Although a single type of silica filler or a combination of two or more types may be used, it is preferable to include two or more types of silica filler from the viewpoint of improving adhesive strength. As an embodiment containing two or more types of silica filler, there is an embodiment in which any two or more types of silica filler are used together from among fused crushed silica, fused spherical silica, crystalline silica, and secondary agglomerated silica. Further, examples include an embodiment in which two or more types of silica fillers with different average particle diameters are used together, and an embodiment in which two or more types of silica fillers with different surface treatments are used in combination.

From the viewpoint of improving the filling property, it is preferable to combine two or more types of fused spherical silica having different average particle diameters _D50 . In this case, the average particle diameter D ₅₀ preferably includes two types, 0.2 to 10 μm and 10 to 100 μm, and the content ratio (mass ratio) of each silica filler is 5:95 to 95:5. The ratio is preferably 10:90 to 90:10. By using the content ratio in the range of 5:95 to 95:5, it is easy to improve the filling property. The content of silica filler can be selected depending on the application.

When the cured product of the thermosetting composition is required to have heat dissipation properties, it is preferable to contain an inorganic filler (C) having thermal conductivity. Specific examples of the inorganic filler (C) include alumina, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, calcium oxide, magnesium oxide, zinc oxide, beryllia, aluminum oxide, aluminum nitride, and nitride. Metal oxides and metal nitrides such as boron; hydrated metal compounds; silica-based materials such as fused silica, crystalline silica, and amorphous silica; nitride-based and carbon-based fillers such as silicon carbide, silicon nitride, titanium carbide, and diamond can be exemplified. Among these, alumina, aluminum oxide, aluminum nitride, and boron nitride are more preferred, and alumina and boron nitride are particularly preferred from the viewpoint of heat resistance, thermal conductivity, and low dielectric constant. A combination of alumina and boron nitride is also suitable.

The surface of the inorganic filler (C) can be surface-treated with, for example, a silane-based, titanate-based, or aluminate-based coupling agent. The surface treatment can improve the dispersibility of the inorganic filler (C) in the polyimide resin (A). Moreover, the interfacial adhesive strength between the polyimide resin (A) and the inorganic filler (C) can also be increased. A silane coupling agent is suitable as a surface treatment agent for silica filler.

A silane coupling agent is a compound having a hydrolyzable group and a reactive functional group. Examples of the hydrolyzable group include an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and an ethoxy group; an acetoxy group; and a 2-methoxyethoxy group. Among these, methoxy group is preferable since volatile components such as alcohol produced by hydrolysis can be easily removed. Examples of the reactive functional group include a vinyl group, an epoxy group, a styryl group, a methacrylic group, an acrylic group, an amino group, a ureido group, a mercapto group, a sulfide group, an isocyanate group, and among them, an epoxy group is preferable.

Examples of the silane coupling agent include vinyl group-containing silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane; 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxy Epoxy group-containing silane coupling agents such as silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane; p-styryltrimethoxysilane, etc. Styryl group-containing silane coupling agent; methacrylic group-containing silane such as 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, etc. Coupling agent; Acrylic group-containing silane coupling agent such as 3-acryloxypropyltrimethoxysilane; N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3- Aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyl Amino group-containing silane coupling agents such as trimethoxysilane and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane; ureido group-containing silane coupling agents such as 3-ureidopropyltriethoxysilane; Mercapto group-containing silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; sulfide group-containing silane coupling agents such as bis(triethoxysilylpropyl)tetrasulfide; 3-isocyanatepropyltriethoxy Examples include isocyanate group-containing silane coupling agents such as silane. As the silane coupling agent, phenylaminosilane treatment and/or vinylsilane treatment is preferable from the viewpoint of developing excellent adhesive strength and heat cycle properties of the curable composition.

Examples of titanate coupling agents include isopropyl triisostearoyl titanate, isopropyl tri(N-aminoethyl aminoethyl) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, and bis(ditridecyl)phosphite titanate. Examples include dioctyl pyrophosphate) oxyacetate titanate, bis(dioctyl pyrophosphate) ethylene titanate, diisopropyl bis(dioctyl phosphate) titanate, tetraisopropyl bis(dioctyl phosphite) titanate, and tetraoctyl bis(ditridecyl phosphite) titanate.

Examples of methods for treating silica filler with a silane coupling agent include a wet method in which the silica filler and the silane coupling agent are mixed in a solvent, and a dry method in which the silica filler and the silane coupling agent are treated in a gas phase. It will be done. The amount of silane coupling agent to be treated is preferably about 0.1 to 1 part by mass per 100 parts by mass of untreated silica filler.

[Compound (D)]
Compound (D) can be used as a curing agent or curing accelerator as an optional component. Compound (D) is one or more selected from phenol resin (d1), benzoxazine (d2), active ester resin (d3), and maleimide compound (d4). By further using the compound (D), it is easy to further promote the three-dimensional network structure of the crosslinking agent (B) contained in the thermosetting composition and to adjust the degree of the three-dimensional network structure. Become. Compound (D) is more preferably combined with epoxy compound (b1) among the options for crosslinking agent (B).

Examples of the phenol resin (d1) include addition compounds of formaldehyde and compounds such as phenol, cresols, and bisphenols, or partial condensates thereof. Specifically, resols of phenol resin, cresol resin, t-butylphenol resin, dicyclopentadiene cresol resin, dicyclopentadiene phenol resin, xylylene modified phenol resin, tetrakis phenol resin, bisphenol A resin, and poly-p-vinylphenol resin. Examples include mold resin and novolak resin. Other examples include naphthol compounds, trisphenol compounds, and phenol aralkyl resins. Among them, resol type resins such as phenolic resins have excellent heat resistance and curability, and can be suitably used in the present invention.

As the benzoxazine compound (d2), "Pa", "P-alp", "P-ala", "B-ala" described in Macromolecules, 36, 6010 (2003), Macromolecules, 34, 7257 (2001) ) "P-appe", "B-appe", "B-a type benzoxazine", "F-a type benzoxazine", "B-m type benzoxazine" manufactured by Shikoku Kasei Co., Ltd. .

The active ester resin (d3) is a resin having two or more active ester groups in one molecule. Active ester resins can generally be obtained by a condensation reaction between a carboxylic acid compound and a hydroxy compound. Among these, active ester compounds obtained using a phenol compound or a naphthol compound as the hydroxy compound are preferred. Examples of phenolic compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalin, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol , dicyclopentadienyl diphenol, phenol novolac, and the like.
Furthermore, the carboxylic acid compound referred to here is a polycarboxylic acid having two or more carboxyl groups, such as aliphatic carboxylic acids such as adipic acid, and aromatic compounds in which 2 to 4 hydrogen atoms are replaced with carboxyl groups. Examples include substituted aromatic carboxylic acids. Polyhydric phenol is a compound having two or more phenolic hydroxyl groups, and includes aromatic compounds in which 2 to 4 hydrogen atoms are replaced with hydroxyl groups.

The maleimide compound (d4) has at least one maleimide group in its molecule, such as phenylmaleimide, 1-methyl-2,4-bismaleimidebenzene, N,N'-m-phenylenebismaleimide. , N,N'-p-phenylenebismaleimide, N,N'-4,4-biphenylenebismaleimide, N,N'-4,4-(3,3-dimethylbiphenylene)bismaleimide, N,N'- 4,4-(3,3-dimethyldiphenylmethane)bismaleimide, N,N'-4,4-(3,3-diethyldiphenylmethane)bismaleimide, N,N'-4,4-diphenylmethanebismaleimide, N, N'-4,4-diphenylpropane bismaleimide, N,N'-4,4-diphenyl ether bismaleimide, N,N'-4,4-diphenylsulfone bismaleimide, 2,2-bis[4-(4- maleimidophenoxy)phenyl]propane, 2,2-bis[3-s-butyl-3,4-(4-maleimidophenoxy)phenyl]propane, 1,1-bis[4-(4-maleimidophenoxy)phenyl]decane , 4,4'-cyclohexylidene-bis[1-(4-maleimidophenoxy)phenoxy]-2-cyclohexylbenzene, 2,2-bis[4-(4-maleimidophenoxy)phenyl]hexafluoropropane, etc. , may be used alone or in combination of two or more.

When using the epoxy compound (b1) as the crosslinking agent (B), the content of the compound (D) is preferably 1 to 200 parts by mass, and 5 to 200 parts by mass, based on 100 parts by mass of the epoxy compound (b1). It is more preferably 150 parts by mass, and even more preferably 10 to 100 parts by mass.

[Catalyst (E)]
The thermosetting composition of the present embodiment may contain a catalyst (E) as an optional component in order to promote crosslinking between the acid anhydride group at the end of the molecular chain of the polyimide resin (A) and the crosslinking agent (B). can. Suitable examples of the catalyst (E) include imidazole type, amine type and phosphorus type.

<Other optional ingredients>
The thermosetting composition may further contain additives without departing from the spirit of the present invention. For example, a polyimide resin that does not fall under the polyimide resin (A) may be used. Further, any thermoplastic resin (elastomer) can be used. Also, dyes, pigments (e.g. carbon black), flame retardants, antioxidants, polymerization inhibitors, antifoaming agents, leveling agents, ion scavengers, humectants, viscosity modifiers, preservatives, antibacterial agents, antistatic agents. agents, anti-blocking agents, ultraviolet absorbers, infrared absorbers, electromagnetic shielding agents, etc.

[Method for producing thermosetting composition]
The thermosetting composition is obtained by blending the respective ingredients. Instead of a polyimide precursor, an imidized polyimide resin (A) is used as a compounding component. When blending, a solvent can be used as appropriate. The solid content concentration can be, for example, 20 to 60 parts by mass. According to the polyimide resin (A) of this embodiment, since it has a dimer structure, it can be easily dissolved in various organic solvents.

The thermosetting composition preferably has a glass transition temperature of 30 to 270°C, more preferably 38 to 260°C, and still more preferably 45 to 255°C after thermosetting at a temperature of 180°C for 60 minutes. preferable. From the viewpoint of improving long-term heat resistance, the temperature is preferably 140 to 250°C. In this case, the more preferred range is 150 to 240°C, and even more preferably 160 to 230°C.

[Method for producing cured product]
A cured product can be obtained by subjecting the thermosetting composition of this embodiment to a thermosetting treatment. An example is a method in which a thermosetting composition is formed into a desired shape such as a sheet, and then subjected to thermosetting treatment. A molded article such as a sheet of a thermosetting composition can be easily obtained by applying and drying a thermosetting composition containing a solvent. Then, a cured product is formed by thermosetting the molded body. The molded body and the curing may be performed at the same time.

The thermosetting temperature may be appropriately selected depending on the type of crosslinking agent (B). For example, a method of heat treatment at a temperature of 150 to 230° C. for 30 to 180 minutes can be exemplified. By thermosetting treatment, crosslinking of the crosslinking agent (B) itself, crosslinking of the polyimide resin (A) and the crosslinking agent (B), crosslinking of the crosslinking agent (B) and the compound (D), or any combination thereof. A structure is formed and a three-dimensionally crosslinked cured product is obtained.

[Applications of thermosetting composition and cured product, etc.]
The thermosetting composition of this embodiment exhibits excellent adhesive properties after curing, and therefore can be used as an adhesive material. In addition, because it has excellent electrical insulation, the circuit board itself or insulating layer forming materials on the circuit board (including coverlay layers of printed wiring boards, interlayer insulating layers such as built-up boards, board forming materials, bonding sheets, etc.), It is suitably used as a resin casting material such as an underfill material, a sealing material for semiconductor chips, a material for forming an insulating layer of a semiconductor chip package, etc. It is also suitable as a bonding material for components such as electronic circuit boards and electronic components.

Since the polyimide resin (A) used in this embodiment has excellent electrical insulation properties, a cured product with excellent insulation properties can be provided. Further, by blending a conductive filler as the inorganic filler (C), it can be suitably used as a conductive adhesive sheet. Furthermore, by using a thermally conductive filler as the inorganic filler (C), it can be applied to all applications requiring heat dissipation. For example, by taking advantage of the moldability of the resin composition, it can be suitably used as a heat dissipation component in a desired shape. In particular, it is useful as a heat dissipation member for electronic devices (smartphones, doublet terminals, etc.) that cannot be equipped with fans or heat sinks due to their miniaturization, and for battery exterior materials. Furthermore, the cured product of the thermosetting composition of this embodiment is suitable as an adhesive layer between a heat generating element and a heat sink, or as a heat spreader. Furthermore, it can be applied as a heat dissipation layer covering one or more electronic components mounted on a substrate.

The thermosetting composition can be, for example, in the form of a powder, film, sheet, plate, pellet, paste, or liquid. A liquid or pasty thermosetting composition can be easily obtained by adjusting the viscosity using a solvent. Further, a film-like, sheet-like, or plate-like thermosetting composition can be formed, for example, by applying a liquid or paste-like thermosetting composition and drying it. Further, a powdered or pelleted thermosetting composition can be obtained, for example, by pulverizing or cutting the above-mentioned film-like thermosetting composition into a desired size.

Moreover, it can be suitably applied to insulating members of electronic components. Examples of electronic components include semiconductor devices and circuit boards. The semiconductor device is, for example, a power module such as a power semiconductor device, an LED, or an inverter device, and the semiconductor device includes, for example, a semiconductor element such as an insulated gate bipolar transistor, a diode, or an IC chip, or various heating elements such as a resistor or a capacitor. is installed. The cured product of the thermosetting composition of this embodiment is used for substrates, insulating layers, sealing materials of semiconductor devices, insulating layers of semiconductor chip packages, underfill materials, adhesives, and the like. Examples of the circuit board include a printed wiring board and a laminate for a circuit board that is not classified as a printed wiring board and is a laminate including a metal layer and an insulating resin layer. It can also be used for thermosetting compositions for copper-clad laminates, bonding sheets for forming wiring boards, cover coats for flexible circuit boards, prepregs, etc.

(wiring board)
The thermosetting composition of this embodiment can be suitably used as adhesive sheets and interlayer insulating layers for printed wiring boards and multilayer wiring boards. An insulating layer (cured sheet) that is a cured product of a thermosetting sheet formed from the thermosetting composition of this embodiment, or an insulation layer that is a cured product of a prepreg formed using the thermosetting composition of this embodiment The layer (cured sheet) is suitable as an adhesive sheet or an interlayer insulation layer. These can be suitably used, for example, as a printed wiring board having a layer made of a cured product obtained by thermally curing the thermosetting composition of this embodiment on a base material.
An opening can be provided in the insulating layer of this embodiment formed on one or both sides of the wiring board by drilling, laser processing, etc., and a via can be formed by filling the opening with a conductive agent. Further, a circuit layer can be formed on the interlayer insulating layer of this embodiment. The thermosetting composition of this embodiment has excellent adhesion and long-term heat resistance, as well as crack resistance and laser processability, so it is suitable for use in multilayer circuit boards having multiple insulating layer/circuit layer configurations. .

(Metal-clad laminate)
The thermosetting composition of this embodiment can be used as a member of a metal-clad laminate. A metal-clad laminate is obtained by forming an insulating layer using a thermosetting composition to obtain a laminate including a laminate structure of an insulating layer and a metal layer. This insulating layer may be an insulating sheet made only of a thermosetting composition, or a sheet made of the prepreg described above. For example, after laminating a metal layer and an insulating sheet made of the thermosetting composition of this embodiment, the insulating sheet is cured by thermocompression bonding to form an insulating layer, and a metal-clad laminate can be obtained. A known method can be used as the heat compression bonding method. For example, hot pressing is carried out at a temperature of 120 to 200° C. and a pressure of 0.5 to 10 MPa for 0.5 to 5 hours.

The laminated structure of the metal-clad laminate may be a two-layer laminate of metal layer/insulating layer, a laminate consisting of multiple layers of metal layer/insulating layer/metal layer, or metal layer/insulating layer/metal layer/insulating layer. An example is a metal-clad laminate having a multilayer structure in which layers/metal layers are alternately laminated. Further, the laminate may include an insulating layer other than the insulating layer formed from the thermosetting composition of this embodiment. Further, in order to adjust the thickness of the insulating layer, a plurality of prepregs can be stacked and cured. Further, conductive layers other than metal layers may be laminated. The resin sheet may contain filler or the like.

For example, a metal-clad laminate having a layer structure of metal layer/insulating layer/metal layer is manufactured by forming a circuit pattern on a metal layer formed on both main surfaces of an insulating layer, thereby producing a circuit board having a circuit pattern layer. can be obtained. Through holes and vias may be formed in the insulating layer using a laser or the like. Insulating layers may be stacked on the core substrate by a build-up process to form vias to form a multilayer structure. A circuit board can be obtained, for example, by forming a desired circuit pattern on the metal layer of a metal-clad laminate using a subtractive method, or by forming a desired circuit pattern on one or both sides of an insulating layer using an additive method. can.

Through holes can be formed in the insulating layer by laser processing. Specific examples include UV-YAG laser, CO ₂ laser and excimer laser.

(prepreg)
The thermosetting composition according to this embodiment can be used as a prepreg by impregnating it into a fiber base material. The prepreg can be produced, for example, by impregnating a fiber base material with the thermosetting composition of this embodiment, and then semi-curing (B-staged) the thermosetting composition by heating and drying.

The amount of solid content of the thermosetting composition on the fiber base material is preferably 20 to 90% by mass based on the content of the thermosetting composition after drying on the prepreg. More preferably, it is 30 to 80% by mass, and still more preferably 40 to 70% by mass. For example, after impregnating or coating a fiber base material with the thermosetting composition of this embodiment so that the solid content of the thermosetting composition in the prepreg is 20 to 90% by mass, for example, It can be produced by heating and drying at a temperature of 200° C. for 1 to 30 minutes to semi-cure (B-stage).

As the fiber base material, any known material can be used without limitation, and examples thereof include organic fibers, inorganic fibers, and glass fibers. Examples of organic fibers include polyimide, polyester, tetrafluoroethylene, and wholly aromatic polyamide. An example of the inorganic fiber is carbon fiber. Examples of the glass fiber include E glass cloth, D glass cloth, S glass cloth, Q glass cloth, NE glass cloth, L glass cloth, T glass cloth, spherical glass cloth, and low dielectric glass cloth. Among these, E glass cloth, T glass cloth, S glass cloth, Q glass cloth and organic fibers are suitable from the viewpoint of low coefficient of thermal expansion. The fiber base materials may be used alone or in combination of two or more.

The shape of the fiber base material can be appropriately selected depending on the intended use and performance. Specific examples include woven fabrics, nonwoven fabrics, raw binders, chopped strand mats, and surfacing mats. Examples of weaving methods for the woven fabric include plain weave, Nanako weave, and twill weave. It can be arbitrarily selected and designed according to desired characteristics. The thickness of the fibrous substrate can range, for example, from about 0.01 to 1.0 mm. From the viewpoint of thinning the film, the thickness is preferably 500 μm or less, more preferably 300 μm or less.

The fiber base material can be subjected to surface treatment with a silane coupling agent or the like or mechanically opened to bring out desired properties, if necessary. In addition, corona treatment or plasma treatment may be performed. Surface treatments of the silane coupling agent include aminosilane coupling treatment, vinyl silane coupling treatment, cationic silane coupling treatment, and epoxysilane coupling treatment.

The method for impregnating the fiber base material with the thermosetting composition is not particularly limited, but examples include alcohols, ethers, acetals, ketones, esters, alcohol esters, ketone alcohols, ether alcohols, and ketone ethers. A method of preparing a thermosetting composition varnish using an organic solvent such as ketone esters or ester ethers, and dipping the fiber base material in the varnish, or applying the varnish to the fiber base material or dispersing it by spraying, etc. Examples include a method of laminating both sides of a fiber base material with a film made of a thermosetting composition.

The present invention will be explained in more detail, but the following examples do not limit the scope of the present invention in any way. In the examples, "parts" are "parts by mass" and "%" are "% by mass." The blending amounts in the table are parts by mass. Further, Example 45 shall be read as Reference Example 45 for the purpose of conforming to the scope of claim 1.

<Method for measuring weight average molecular weight (Mw)>
The Mw was measured using GPC (gel permeation chromatography) "GPC-101" manufactured by Showa Denko. GPC is liquid chromatography that separates and quantifies substances dissolved in a solvent (THF: tetrahydrofuran) based on the difference in molecular size. The measurement in the present invention uses two "KF-805L" columns (manufactured by Showa Denko Co., Ltd.: GPC column: 8 mm ID x 300 mm size) connected in series, sample concentration of 1% by mass, flow rate of 1.0 mL/min, It was carried out under the conditions of a pressure of 3.8 MPa and a column temperature of 40° C., and the weight average molecular weight (Mw) was determined in terms of polystyrene. For data analysis, the calibration curve, molecular weight, and peak area were calculated using the manufacturer's built-in software, and the weight average molecular weight was determined using the retention time range of 17.9 to 30.0 minutes as the analysis target.

<Method for measuring glass transition temperature of polyimide resin (A)>
A polyimide resin varnish was prepared by dissolving polyimide resin in cyclohexanone so that the nonvolatile content was 35%. This varnish was applied onto a heat-resistant release film using a 10 mil doctor blade and dried at 130° C. for 10 minutes to obtain a 25 μm thick polyimide resin film, which was used as a sample for glass transition temperature measurement. Tan δ was measured in a temperature range of -50 to 200°C using a dynamic viscoelasticity measuring device to determine the glass transition temperature.
Dynamic viscoelasticity measurement device: DVA-200 (manufactured by IT Keizai Control Co., Ltd.)
Temperature increase rate: 10℃/min
Measurement frequency: 10Hz
Length between grips: 15mm
Width: 5mm

<Method for measuring functional group value of polyimide resin (A)>
<Measurement of acid value>
Approximately 1 g of the sample was accurately weighed into a stoppered Erlenmeyer flask, and 100 mL of cyclohexanone solvent was added to dissolve it. Add phenolphthalein test solution to this as an indicator and hold for 30 seconds. Thereafter, it is titrated with 0.1N alcoholic potassium hydroxide solution until the solution takes on a pale pink color. The acid value was determined by the following formula (unit: mgKOH/g).
Acid value (mgKOH/g) = (5.611 x a x F)/S
however,
S: Amount of sample collected (g)
a: Consumption amount (mL) of 0.1N alcoholic potassium hydroxide solution
F: Titer of 0.1N alcoholic potassium hydroxide solution

<Measurement of amine value>
Approximately 1 g of the sample was accurately weighed into a stoppered Erlenmeyer flask, and 100 mL of cyclohexanone solvent was added to dissolve it. To this, add a few drops of an indicator separately prepared by mixing 0.20 g of Methyl Orange dissolved in 50 mL of distilled water and 0.28 g of Xylene Cyanol FF dissolved in 50 mL of methanol. Hold for seconds. It is then titrated with 0.1N alcoholic hydrochloric acid solution until the solution assumes a blue-gray color. The amine value was determined by the following formula (unit: mgKOH/g).
Amine value (mgKOH/g) = (5.611×a×F)/S
however,
S: Amount of sample collected (g)
a: Consumption amount of 0.1N alcoholic hydrochloric acid solution (mL)
F: Titer of 0.1N alcoholic hydrochloric acid solution

<Method for measuring acid anhydride value>
Approximately 1 g of the sample was accurately weighed into a stoppered Erlenmeyer flask, and 100 mL of 1,4-dioxane solvent was added to dissolve it. Add 10 mL of a mixed solution of octylamine, 1,4-dioxane, and water (mass mixing ratio: 1.49/800/80) in an amount greater than the amount of acid anhydride groups in the sample, stir for 15 minutes, and remove the acid anhydride. reacted with a substance. Thereafter, excess octylamine was titrated with a mixed solution of 0.02M perchloric acid and 1,4-dioxane. Additionally, 10 mL of a mixed solution of octylamine, 1,4-dioxane, and water (mixing ratio of mass: 1.49/800/80) to which no sample was added was also used as a blank for measurement. Acid anhydride value was determined by the following formula (unit: mgKOH/g)
Acid anhydride price (mgKOH/g) = 0.02 x (BS) x F x 56.11/W
B: Blank titer (mL)
S: Titration amount of sample (mL)
W: Sample solid amount (g)
F: 0.02mol/L perchloric acid titer

<Synthesis of polyimide resin>
[Polyimide resin (A-1)]
[Synthesis example 1]
Cyclohexanone (200 g) was added to a 1 L separable flask equipped with a stirring bar equipped with an oil bath while introducing nitrogen gas, and 68.6 g (68.6% by mass) of dimer diamine (PRIAMINE1075) was added as a diamine while stirring. Then, 31.4 g (31.4% by mass) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride was added as a tetracarboxylic dianhydride, and the mixture was stirred at room temperature for 30 minutes. After raising the temperature to 100°C and stirring for 3 hours, the oil bath was removed and the temperature was returned to room temperature to obtain a varnish-like polyimide precursor. Thereafter, while removing distilled water from the system using a Dean-Stark trap, heating was performed at 170° C. for 10 hours to imidize and obtain a polyimide resin. Table 1 shows the weight average molecular weight (Mw), Tg, and functionalization of the obtained polyimide resin.

[Synthesis Examples 2 to 15, Synthesis Examples 16 to 20 (Comparative Synthesis Examples)]
A polyimide resin was obtained in the same manner as in Synthesis Example 1 except that the monomers listed in Tables 1 and 2 were used. The Mw and Tg of the obtained polyimide resin are shown in Table 1 or Table 2.

The contents of the abbreviations in Table 1 are shown below.
BISDA: 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride PMDA: Pyromellitic anhydride TDA: 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2 , 3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride HPMDA: 1,2,4,5-cyclohexanetetracarboxylic dianhydride BTCA: 1,2,3,4-butanetetracarboxylic dianhydride TTC: 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid HPMTC: 1,2,4,5-cyclohexanetetracarboxylic acid BTC : 1,2,3,4-butanetetracarboxylic acid TMA: Trimellitic anhydride DDA1: Dimer diamine (trade name "PRIAMINE1075", manufactured by Croda Japan)
DDA2: Dimer diamine (trade name "PRIAMINE1074", manufactured by Croda Japan)
DADE: 4,4'-diaminodiphenyl ether Note that the functional group values in Table 1 indicate the acid anhydride value for Synthesis Examples 1 to 18, the acid value for Synthesis Example 19, and the amine value for Synthesis Example 20.

Details of the materials used in Examples and Comparative Examples are shown below.
(Crosslinking agent (B))
HP-7200H: Epoxy compound 1 (manufactured by DIC, dicyclopentadiene type polyfunctional epoxy resin, softening point 83°C)
HP-4710: Epoxy compound 2 (manufactured by DIC, ultra-high heat resistant epoxy resin, softening point 95°C)
N-660: Epoxy compound 3 (manufactured by DIC, cresol novolak type epoxy resin, softening point 40°C or higher)
TETRAD-X: Epoxy compound 4 (manufactured by Mitsubishi Gas Chemical Co., Ltd., tetrafunctional glycidylamine compound, room temperature liquid (softening point less than 40°C))
BA230S75: Cyanate ester compound (manufactured by Lonza, polyfunctional cyanate ester compound)
BL3175: Isocyanate group-containing compound (manufactured by Sumika Bayer Urethane Co., Ltd., trifunctional isocyanurate type blocked isocyanate)
Aluminum chelate A: chelate compound (manufactured by Kawaken Fine Chemicals, trifunctional Al chelate compound)
V-07: Carbodiimide group-containing compound (manufactured by Nisshinbo, polyfunctional polycarbodiimide compound)
Denacol EX-321: Liquid epoxy resin (manufactured by Nagase ChemteX, room temperature liquid)

(Inorganic filler (C))
SO-C1: Silica (manufactured by Admatex, average particle size 0.25 μm)

(Compound (D))
H-4: Phenol resin (manufactured by Meiwa Kasei Co., Ltd.)
P-d type benzoxazine: Benzoxazine (manufactured by Shikoku Kasei Co., Ltd.)
HPC8000-65T: Active ester resin (manufactured by DIC)
Rikacid MH: Acid anhydride (4-methylhexahydrophthalic anhydride, manufactured by Shinnihon Chemical Co., Ltd.)
DPB: maleimide compound (4,4'-diphenylmethane bismaleimide, bifunctional maleimide compound)

(Catalyst (E))
2P4MZ: Catalyst 1 (manufactured by Shikoku Kasei Co., Ltd., imidazole-based catalyst)
DBU: Catalyst 2 (amine catalyst)
TPP: Catalyst 3 (phosphonium catalyst)

(Other resins)
Zylon S201A: Polyphenylene ether resin (manufactured by Asahi Kasei Corporation)
SMA1000: Styrene maleic anhydride copolymer (manufactured by CRAYVALLEY)
HR-15ET: Polyamideimide resin (manufactured by Toyobo Co., Ltd.)

<Method of measuring softening point>
The softening point is measured by the ring and ball method in accordance with JIS K-2207. That is, a specified ring is filled with a sample, supported horizontally in a water bath or glycerin bath, a specified sphere is placed in the center of the sample, and the bath temperature is increased at a rate of 5°C/min. , the temperature when touching the bottom plate of the ring stand is the softening point.

<Method for measuring glass transition temperature of cured product>
The thermosetting compositions of each example and comparative example were coated on a release film and dried at 120° C. for 2 minutes to produce a thermosetting sheet with a release film on one side so as to have a thickness of about 30 μm. This thermosetting sheet with a single-sided release film was thermally cured at 180° C. for 60 minutes, and the release film was removed to prepare a sample for glass transition temperature measurement. Tan δ was measured in a temperature range of -50 to 200°C using a dynamic viscoelasticity measuring device to determine the glass transition temperature.
Dynamic viscoelasticity measurement device: DVA-200 (manufactured by IT Keizai Control Co., Ltd.)
Temperature increase rate: 10℃/min
Measurement frequency: 10Hz
Length between grips: 15mm
Width: 5mm

<Adhesiveness>
The thermosetting sheet with a single-sided release film prepared in the above glass transition temperature measurement test was cut into a size of 65 mm x 65 mm, the release film was removed, and a polyimide film with a thickness of 75 μm [DuPont-Toray Co., Ltd. "Kapton 300H" manufactured by Kapton Co., Ltd.] and laminated at 80°C, followed by pressure bonding at 180°C and 1.0 MPa for 30 minutes. Furthermore, this test piece was heat-cured at 180° C. for 1 hour to prepare a test piece for evaluation. This test piece was cut out to a width of 10 mm and a length of 65 mm, and a T-peel peel test was performed at a pulling speed of 300 mm/min at 23° C. and an atmosphere of 50% relative humidity to measure the adhesive strength (N/cm). This test evaluated the adhesive strength of the adhesive layer when used at room temperature, and the results were judged based on the following criteria.
A..."12 (N/cm)<adhesion strength"
B... "8 (N/cm)<adhesion strength≦12 (N/cm)"
C..."5 (N/cm)<adhesion strength≦8 (N/cm)"
D... "3 (N/cm)<adhesion strength≦5 (N/cm)"
E... "Adhesive strength ≦ 3 (N/cm)"

<Evaluation of soldering heat resistance>
Similar to the above adhesion test, a test piece cut out to a width of 10 mm and a length of 65 mm was stored at 23°C in an atmosphere of 50% relative humidity for more than 24 hours, and then the polyimide film surface was applied to molten solder at various temperatures. were brought into contact with each other and floated for 1 minute. Thereafter, the appearance of the test piece was visually observed, and the presence or absence of adhesion abnormalities such as foaming, lifting, and peeling of the cured adhesive layer (cured sheet) was evaluated. This test evaluates the thermal stability of the cured adhesive layer when it comes into contact with solder, based on its appearance. Those with good heat resistance will not change in appearance, while those with poor heat resistance will not change when soldering. Foaming and peeling occur after treatment. These evaluation results were judged based on the following criteria.
A: There is no change in appearance even at 300°C.
B: No change in appearance at 280°C. Foaming is confirmed at 300°C.
C: No change in appearance at all even at 260°C. Foaming is confirmed at 280°C.
D...No change in appearance even at 240°C. Foaming is confirmed at 260°C.
E: Foaming is observed at 240°C.

<Long-term heat resistance>
Similar to the above adhesion test, a test piece cut out to a width of 10 mm and a length of 65 mm was stored in an air atmosphere at 150° C. for 1000 hours or more, and after being taken out, the adhesive strength was measured. The degree of decrease in adhesive strength from that at room temperature was confirmed, and the results were judged based on the following criteria.
A: The rate of decrease in adhesive strength is less than 20% compared to the adhesive strength at room temperature.
B: The rate of decrease in adhesive strength is 20% or more and less than 40% compared to the adhesive strength at room temperature.
C: The rate of decrease in adhesive strength is 40% or more and less than 60% compared to the adhesive strength at room temperature.
D: The rate of decrease in adhesive strength is 60% or more and less than 80% compared to the adhesive strength at room temperature.
E: Adhesive strength decreases by 80% or more compared to adhesive strength at room temperature.

<Crack resistance>
An adhesive sheet (thermosetting sheet) with a size of 65 mm x 65 mm from which the protective film was removed was bonded to a polyimide film with a thickness of 25 μm [Kapton 100H, manufactured by DuPont-Toray Co., Ltd.] and a copper circuit was formed on the polyimide. The formed comb-shaped pattern (conductor pattern width/space width = 50 μm/50 μm) was sandwiched between the printed wiring board and laminated at 80°C, followed by pressure bonding at 180°C and 1.0 MPa for 30 minutes. Ta. Furthermore, this test piece was heat-cured at 180° C. for 2 hours to prepare a test piece for evaluation. The evaluation test piece was placed in a thermal cycle machine that cycles the temperature between -65°C and 150°C, and crack resistance was confirmed. Then, the surface of the cured film was observed at 400 cycles, 600 cycles, 800 cycles, and 1000 cycles. The judgment criteria are as follows.
A: No abnormality after 1000 cycles.
B: No abnormality after 800 cycles, cracks occurred after 1000 cycles.
C: No abnormality after 600 cycles, cracks occurred after 800 cycles.
D: No abnormality after 400 cycles, cracks occurred after 600 cycles.
E: Cracks occurred after 400 cycles.

<Laser processability>
The light release film is peeled off from the thermosetting adhesive sheet with a double-sided release film, and the exposed thermosetting adhesive sheet surface is used as one side of a double-sided copper-clad laminate made by laminating 12 μm copper foil on both sides of a 50 μm polyimide film. Temporarily adhered to the copper foil on the surface.
Next, the heavy release film was peeled off, and the polyimide film side of the single-sided copper-clad laminate, which was made by laminating a 50 μm polyimide film and 12 μm copper foil, was temporarily attached to the exposed thermosetting adhesive sheet surface using a vacuum laminator. After adhering, it was thermally cured in a heat press at 180°C for 1 hour at 2 MPa to form copper foil (1) / polyimide film (2) / copper foil (2) / cured product of thermosetting adhesive sheet (1) / An evaluation sample with a laminated structure of polyimide film (2)/copper foil (3) was obtained.

The above sample was irradiated with laser from the copper foil (1) side using a UV-YAG laser (Model 5330, manufactured by ESI), and a blind via with a diameter of 150 μm was formed to the boundary between the adhesive layer and the double-sided copper-clad laminate. Processed.
Next, the cross section of the blind via section was observed using a laser microscope (VK-X100 manufactured by Keyence Corporation) at a magnification of approximately 20 to 500 times, and side etching (with an opening diameter larger than the designed opening diameter) that occurred in the cured thermosetting adhesive sheet was observed. The maximum length of horizontal scraping) was measured and evaluated based on the following criteria.
A...5 μm or less.
B: greater than 5 μm and less than 7 μm.
C: greater than 7 μm and less than 9 μm.
D: greater than 9 μm and less than 10 μm.
E... larger than 10 μm.

From the results in Tables 3 to 5, it can be seen that the thermosetting compositions of Examples 1 to 45 are excellent in adhesiveness, solder heat resistance, long-term heat resistance, crack resistance, and laser processability.

Claims (15)

General formula (1):

(X ¹ is a tetravalent tetracarboxylic acid residue independently for each repeating unit, X ² is a divalent diamine residue independently for each repeating unit, and the above X ¹ and imide bond are bonded to each other. to form two imide rings.)
A polyimide resin (A) containing a repeating unit having the structure represented by the formula and a molecular chain end of an acid anhydride group and having a glass transition temperature of 0 to 90°C;
A thermosetting composition containing a crosslinking agent (B),
The above-mentioned X ¹ in the polyimide resin (A) includes X ¹ a having a structure S satisfying at least one of the following (I) and (II), and when the entire X ¹ is taken as 100 mol%, the above-mentioned The proportion of X ¹ a is 60 to 100 mol %, the X ² includes X ² d having a dimer structure, and the X ² in the polyimide resin (A) accounts for 100 mol % of the entire X ² . when the proportion of X ² d is 40 to 100 mol%,
The weight average molecular weight of the polyimide resin (A) is 3,000 to 100,000,
The polyimide resin (A) has an equivalent ratio α/β of the polymerizable functional group α of the monomer Y ¹ constituting the X ¹ and the polymerizable functional group β of the monomer Y ² constituting the X ² . It is obtained by polymerizing in the range of 1.01 to 5.0,
The crosslinking agent (B) is one or more selected from the group consisting of an epoxy compound (b1), a cyanate ester compound (b2), an isocyanate group-containing compound (b3), a chelate compound (b4), and a carbodiimide group-containing compound (b5). A thermosetting composition.
(I) At least one carbon in X ¹ constituting the imide ring is directly bonded to at least one carbon in X ¹ constituting the other imide ring.
(II) At least one of the carbons in X ¹ constituting each of the two imide rings each independently has a structure that is directly connected to an aliphatic structure, and contains an aliphatic structure that is one of the constituent elements. , satisfies either of the following. General formula (1):

(X ¹ are independently tetravalent tetracarboxylic acid residues for each repeating unit, and ² represents a divalent diamine residue independently for each repeating unit, and ¹ and imide bonds combine with each other to form two imide rings. )
A polyimide resin (A) containing a repeating unit having the structure represented by the formula and a molecular chain end of an acid anhydride group and having a glass transition temperature of 0 to 90°C;
A thermosetting composition containing a crosslinking agent (B),
The above X in the polyimide resin (A) ¹ has a structure S that satisfies at least one of the following (I) and (II) ¹ including a, and the relevant X ¹ When the whole is 100 mol%, the above X ¹ The proportion of a is 60 to 100 mol%, and the ² is X with a dimeric structure ² d, and the above X in the polyimide resin (A) ² is the relevant X ² When the whole is 100 mol%, the above X ² The proportion of d is 40 to 100 mol%,
The weight average molecular weight of the polyimide resin (A) is 3,000 to 100,000,
The acid anhydride value of the polyimide resin (A) is 4.4 to 48.7,
The crosslinking agent (B) is one or more selected from the group consisting of an epoxy compound (b1), a cyanate ester compound (b2), an isocyanate group-containing compound (b3), a chelate compound (b4), and a carbodiimide group-containing compound (b5). A thermosetting composition.
(I) Said X constituting said imide ring ¹ the above-mentioned X in which at least one carbon constitutes the other imide ring; ¹ directly bonded to at least one of the carbons in the
(II) The X constituting each of the two imide rings ¹ At least one of the carbons independently satisfies either of having a structure directly connected to an aliphatic structure and containing an aliphatic structure that is one of the constituent elements. The thermosetting composition according to claim 1 or 2 , characterized in that the epoxy compound (b1) contains an epoxy compound having a softening point of 30 to 120°C. Claim 1 further comprising a compound (D) which is one or more selected from phenol resin (d1), benzoxazine (d2), active ester resin (d3) and maleimide compound (d4). 3. The thermosetting composition according to any one of 3 to 3 . 5. The thermosetting composition according to claim 4 , wherein the compound (D) is one or more selected from benzoxazine (d2) and maleimide compound (d4). The thermosetting composition according to any one of claims 1 to 5 , characterized in that it contains an inorganic filler (C). 7. The thermosetting composition according to claim 1, which has a glass transition temperature of 140 to 250°C after thermosetting at 180°C for 60 minutes. The thermosetting composition according to any one of claims 1 to 7 , characterized in that it contains 9.1 to 91% by mass of polyimide resin based on 100% by mass of the thermosetting composition excluding the solvent. 9. The thermosetting composition according to claim 1, wherein the inorganic filler (C) is present in an amount of 0 to 300 parts by mass based on 100 parts by mass of the polyimide resin (A). Polyimide resin (A) has general formula (2):

(X ³ represents a tetravalent tetracarboxylic acid residue, X ³ and the acid anhydride group are bonded to each other to form an acid anhydride ring, and X ³ and the imide bond are bonded to each other to form an imide ring. It has a molecular chain end represented by
The heat according to any one of claims 1 to 9 , wherein the X ³ in the molecular chain terminal of the polyimide resin (A) includes an X ³ t having a structure T satisfying at least one of the following (III) and (IV). Curable composition.
(III) At least one of the carbon atoms in X ³ constituting the acid anhydride ring is directly bonded to at least one carbon in X ³ constituting the imide ring.
(IV) A structure in which at least one of the carbons in X ³ constituting the acid anhydride ring and at least one carbon in X ³ constituting the imide ring are each independently directly connected to an aliphatic structure. and contains an aliphatic structure that is one of the constituent elements. A thermosetting sheet obtained by impregnating a fiber base material with the thermosetting composition according to any one of claims 1 to 10 . A cured product obtained by thermosetting the thermosetting composition according to any one of claims 1 to 10 . 11. A cured sheet obtained by thermosetting the thermosetting sheet according to claim 1 . A printed wiring board comprising a layer made of the cured product according to claim 12 on a base material. A printed wiring board comprising the cured sheet according to claim 13 .