WO2022210671A1

WO2022210671A1 - Curable adhesive composition and cured product

Info

Publication number: WO2022210671A1
Application number: PCT/JP2022/015341
Authority: WO
Inventors: 健太西嶋; 幹広樫尾
Original assignee: リンテック株式会社
Priority date: 2021-03-30
Filing date: 2022-03-29
Publication date: 2022-10-06
Also published as: TW202248387A; KR20230164004A; CN117098825A; JPWO2022210671A1; CN117098825A8

Abstract

The present invention provides a curable adhesive composition which contains (A) a binder resin that has a reactive functional group and (B) a crosslinking agent that is reactive with the component (A), while having a molecular weight of 1000 or less, wherein the content of the component (B) is 0.1% by mass or more relative to the total amount of the active ingredients of this curable adhesive composition. A cured product that has a dielectric loss tangent of less than 0.0050 at 23°C at a frequency of 1 GHz is obtained by curing this curable adhesive composition. The present invention also provides a cured product of this curable adhesive composition.

Description

Curable adhesive composition and cured product

The present invention relates to a curable adhesive composition that gives a cured product with excellent low dielectric properties in a high frequency range and that does not easily contaminate the surroundings during the bonding process, and the cured product thereof. In this specification, the high frequency region refers to the region from 300 MHz to 300 GHz.

In recent years, with the miniaturization and weight reduction of electronic equipment, the use of flexible printed circuit boards (FPC) as wiring members has increased.
An FPC can be obtained, for example, by etching the copper foil of an insulating resin film such as polyimide (copper-clad laminate) to form an electric circuit.
Moreover, usually, a coverlay film having an insulating resin base material and an adhesive layer is attached to a copper foil having an electric circuit formed thereon to protect the electric circuit.

By the way, in recent years, regarding communication devices such as smartphones, the frequency of electric signals has been increasing in order to handle larger amounts of data.
However, since electrical signals in a high frequency range are easily converted into heat, increasing the frequency of electrical signals tends to increase transmission loss.

In order to transmit electrical signals in the high frequency range at high speed while suppressing transmission loss, the dielectric properties of the insulators (base materials, adhesives, etc.) Tangentization) has been done.

Patent Document 1 discloses an adhesive composition containing a styrene-based elastomer, a modified polyphenylene ether resin, an epoxy resin, and an epoxy resin curing agent, and a thermosetting adhesive layer made of this adhesive composition on a substrate. Formed thermosetting adhesive sheets are described.
Patent Document 1 also describes that the adhesive composition has a low dielectric constant and a low dielectric loss tangent.

JP 2019-135280 A

The adhesive composition and its cured product described in Patent Document 1 have low dielectric properties (in this specification, "low dielectric properties" means "low dielectric constant and low dielectric loss tangent". ).
However, in order to cope with the further increase in the frequency of electrical signals expected in the future, it has been desired to form a cured product that is even more excellent in low dielectric properties in the high frequency region.
In addition, with regard to conventional curable adhesive compositions, the fluidity before curing is too high, which can cause contamination of the surroundings during the bonding process.

The present invention has been made in view of the above circumstances, and provides a curable adhesive composition that gives a cured product excellent in low dielectric properties in a high frequency region and does not easily contaminate the surroundings in the bonding process, and a cured product thereof. intended to provide

The inventors diligently studied to solve the above problems. As a result, for a curable adhesive composition that contains a binder resin and gives a cured product with excellent low dielectric properties, by blending a cross-linking agent that can react with the binder resin, contamination of the surroundings during the adhesion process can be suppressed. The inventors have found that and completed the present invention.

Thus, according to the present invention, the following curable adhesive compositions [1] to [10] and cured products [11] to [15] are provided.

[1] Curability containing the following components (A) and (B), wherein the content of component (B) is 0.1% by mass or more relative to the total amount of active ingredients in the curable adhesive composition An adhesive composition comprising:
A curable adhesive composition that, when cured, gives a cured product having a dielectric loss tangent of less than 0.0050 at 23° C. and a frequency of 1 GHz.
Component (A): a binder resin having a reactive functional group Component (B): a cross-linking agent having a molecular weight of 1000 or less that can react with the component (A) [2] The component (A) is a polyolefin resin , the curable adhesive composition according to [1].
[3] The curable adhesive composition according to [1] or [2], wherein the component (A) is an acid-modified resin.
[4] The curable adhesive composition according to any one of [1] to [3], wherein the component (B) is a compound having an isocyanurate skeleton.
[5] The curable adhesive composition according to any one of [1] to [4], wherein the component (B) is a compound having two or more isocyanate groups.
[6] The curable adhesive composition according to any one of [1] to [5], further comprising the following component (C).
Component (C): A non-aromatic curable compound that is liquid at 25° C. [7] Component (C) is a compound having two or more hydrocarbon groups with double bonds at their terminals [6] A curable adhesive composition as described.
[8] The curable adhesive composition according to any one of [1] to [7], further comprising the following component (D).
Component (D): Polyphenylene ether resin having a reactive functional group [9] The curable adhesive composition according to any one of [1] to [8], further comprising the following component (E).
Component (E): Cationic polymerization initiator [10] The curable adhesive composition gives a cured product having a dielectric constant of 3.00 or less at 23° C. and a frequency of 1 GHz when cured [1 ] to [9].
[11] A cured product obtained by curing the curable adhesive composition according to any one of [1] to [10].
[12] The cured product of [11], wherein the cured product has thermosetting properties.
[13] The cured product of [11] or [12], which has a sheet-like shape.
[14] The cured product according to any one of [11] to [13], which is a sheet adhesive for electronic devices.
[15] The cured product according to any one of [11] to [13], wherein the cured product is a sheet adhesive for coverlay films.

According to the present invention, there are provided a curable adhesive composition that gives a cured product with excellent low dielectric properties in a high frequency range and that does not easily contaminate the surroundings in the bonding process, and a cured product thereof.

FIG. 2 is a schematic diagram (plan view) of a part of a laminate used when evaluating the exudation of an adhesive component. FIG. 2 is a schematic diagram showing a cross section taken along line AA of FIG. 1;

Hereinafter, the present invention will be described in detail by dividing into (1) a curable adhesive composition and (2) a cured product.

For the numerical ranges described herein, the upper and lower limits can be combined arbitrarily. For example, when the numerical range is described as "preferably 30 to 100, more preferably 40 to 80", the range of "30 to 80" and the range of "40 to 100" are also described in this specification. included in the specified numerical range. Further, for example, when the numerical range is described as "preferably 30 or more, more preferably 40 or more, and preferably 100 or less, more preferably 80 or less", "30 to 80" Ranges and ranges from "40 to 100" are also included in the numerical ranges described herein.
Also, as a numerical range described in this specification, for example, the description of "60 to 100" means a range of "60 or more and 100 or less".
Furthermore, in the definition of the upper limit value and the lower limit value described in this specification, it is possible to define the numerical range from the lower limit value to the upper limit value by appropriately selecting from each option and combining them arbitrarily.
In addition, various requirements described as preferred embodiments described herein can be combined.

In the present specification, the number average molecular weight (Mn) can be obtained as a standard polystyrene conversion value by performing gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent. can be measured by
(Example of measurement conditions)
・ Gel permeation chromatograph device: manufactured by Tosoh Corporation, product name “HLC-8020”
・ Column: "TSK guard column HXL-L", "TSK gel G2500HXL", "TSK gel G2000HXL" and "TSK gel G1000HXL" sequentially connected (all manufactured by Tosoh Corporation)
・Column temperature: 40°C
・Developing solvent: tetrahydrofuran ・Flow rate: 1.0 mL/min

(1) Curable adhesive composition The curable adhesive composition of the present invention contains the following components (A) and (B), and the content of component (B) is A curable adhesive composition containing 0.1% by mass or more of the total amount of active ingredients.
Component (A): a binder resin having a reactive functional group Component (B): a cross-linking agent having a molecular weight of 1000 or less that can react with the component (A) The curable adhesive composition of the present invention can be cured by curing. , 23° C. and a frequency of 1 GHz.
As used herein, the term "active ingredient" refers to a component in the composition other than the solvent.

In this specification, the cross-linking reaction involving the binder resin (A) and the cross-linking agent (B) is referred to as "curing reaction (I)", and the cured product obtained mainly through the progress of curing reaction (I) is referred to as " It may be described as “cured product (I)”.
The cured product (I) should be cured at least to such an extent that exudation of the adhesive component in the coating film is suppressed. Therefore, the cured product (I) may be one in which the curing reaction (I) is almost completed, or contains an unreacted binder resin (A) and a cross-linking agent (B), and has undergone the curing reaction (I). It may have curability derived from it.

The curable adhesive composition of the present invention contains a curable component other than the binder resin (A) and the cross-linking agent (B) (hereinafter sometimes referred to as “curable component (X)”). good too.

The curable component (X) may be a compound that participates in the curing reaction (I) or a compound that does not participate in the curing reaction (I).
It is possible to obtain a curable adhesive composition that can reliably perform a plurality of curing reactions and more reliably suppress exudation of the adhesive component in the coating film, so the curable component (X) is Compounds that do not participate in the curing reaction (I) are preferred.
That is, when the curable component (X) is a compound that participates in the curing reaction (I), both the step of building a crosslinked structure in the coating film and the step of bonding the two adherends more firmly Since the curing reaction (I) is required, it is necessary to temporarily stop the curing reaction (I) that has been started to build a crosslinked structure in the coating film, and the curing reaction (I) is highly controlled. There is a need.
On the other hand, when the curable component (X) is a compound that does not participate in the curing reaction (I), even if the curing reaction (I) is almost completed, the resulting cured product (I) is not affected by the curable component (X). Since it has curability derived from it, it is possible to carry out a step of bonding two adherends more strongly by utilizing this curability. Thus, the curable adhesive composition containing the curable component (X) that does not participate in the curing reaction (I) can ensure multiple curing reactions without highly controlling the curing reaction (I). It is possible to more reliably prevent the adhesive component from oozing out of the coating film.

In this specification, the curing reaction involving the curable component (X) that does not participate in the curing reaction (I) is sometimes referred to as "curing reaction (II)".

The curable component (X) includes the following components (C), (D) and (F).
Component (C): Non-aromatic curable compound that is liquid at 25° C. Component (D): Polyphenylene ether resin having a reactive functional group Component (F): Silane coupling agent

When the curing reaction (I) or curing reaction (II) is a cationic polymerization reaction, the curable adhesive composition of one embodiment of the present invention may further contain the following component (E).
Component (E): Cationic polymerization initiator Further, the curable adhesive composition of one embodiment of the present invention further includes components other than the above components (A) to (F), as long as the effects of the present invention are not impaired. may contain ingredients.

In the curable adhesive composition of one aspect of the present invention, the total content of components (A) and (B) is 40% by mass or more, 50% by mass or more, 60% by mass or more, 65% by mass or more, or 70% by mass or more, and 100% by mass or less, 99% by mass or less, 95% by mass or less, 90% by mass or less , 85% by mass or less, or 80% by mass or less.

In the curable adhesive composition of one aspect of the present invention, the total content of components (A) to (E) is based on the total amount (100% by mass) of active ingredients in the curable adhesive composition, 45% by mass or more, 55% by mass or more, 65% by mass or more, 75% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more, or 100% by mass Below, it is good also as 99.9 mass % or less, or 99.8 mass % or less.

In the curable adhesive composition of one aspect of the present invention, the total content of components (A) to (F) is based on the total amount (100% by mass) of active ingredients in the curable adhesive composition, 45 to 100% by mass, 55% by mass or more, 65% by mass or more, 75% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more, or 100% by mass % or less, 99.9 mass % or less, or 99.8 mass % or less.

[(A) component: binder resin having a reactive functional group]
The curable adhesive composition of the present invention contains, as component (A), a binder resin having a reactive functional group (hereinafter sometimes referred to as "binder resin (A)").
Since the curable adhesive composition of the present invention contains the binder resin (A), contamination of the surroundings during the adhesion process can be suppressed, as will be described later.
Binder resin (A) can be used individually by 1 type or in combination of 2 or more types.

The number average molecular weight (Mn) of the binder resin (A) is not particularly limited. 000, more preferably 10,000 to 100,000.
The number average molecular weight (Mn) of the binder resin (A) can be obtained as a standard polystyrene conversion value by performing gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent, and specific measurement The conditions are as described above.

The content of the binder resin (A) contained in the curable adhesive composition (the total amount of these when two or more binder resins (A) are included) is the total amount of active ingredients in the curable adhesive composition ( 100% by mass), preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 65% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, More preferably 85 mass % or less, still more preferably 80 mass % or less.
When the content of the binder resin (A) is 50% by mass or more, it becomes easier to obtain a curable adhesive composition that does not easily stain the surroundings.
When the content of the binder resin (A) is 95% by mass or less, it becomes easier to obtain a curable adhesive composition that gives a cured product with excellent low dielectric properties.

Examples of the binder resin (A) include polyolefin-based resins, phenoxy-based resins, polyimide-based resins, polyamideimide-based resins, polyvinyl butyral-based resins, and polycarbonate-based resins.
Among these, polyolefin-based resins are preferable as the binder resin (A). When the binder resin (A) is a polyolefin resin, it becomes easier to obtain a curable adhesive composition that gives a cured product with excellent low dielectric properties.

In the case of a curable adhesive composition in which the component (A) is a polyolefin resin, the curable adhesive composition may contain a binder resin other than the polyolefin resin as another component. good.
In the curable adhesive composition, the content of the other binder resin is preferably 0 to 50 parts by mass, more preferably 0 to 30 parts by mass, and still more preferably 100 parts by mass of the total polyolefin resin. 0 to 10 parts by weight, more preferably 0 to 5 parts by weight.

A polyolefin resin is a polymer containing repeating units derived from an olefin monomer. The polyolefin resin may be a polymer consisting only of repeating units derived from an olefinic monomer, or a repeating unit derived from an olefinic monomer and a monomer copolymerizable with the olefinic monomer. It may be a polymer composed of repeating units derived from

The olefinic monomer is preferably an α-olefin having 2 to 8 carbon atoms, more preferably ethylene, propylene, 1-butene, isobutylene, or 1-hexene, and still more preferably ethylene or propylene. These olefinic monomers can be used singly or in combination of two or more.
Examples of monomers copolymerizable with olefinic monomers include vinyl acetate, (meth)acrylic acid esters, and styrene. Here, "(meth)acrylic acid" means acrylic acid or methacrylic acid (same below).
These "monomers copolymerizable with olefinic monomers" can be used singly or in combination of two or more.

Polyolefin resins include very low density polyethylene (VLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene, polypropylene (PP), ethylene-propylene Copolymers, olefinic elastomers (TPO), ethylene-vinyl acetate copolymers (EVA), ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, and the like.

Reactive functional groups contained in the binder resin (A) include a carboxy group, a carboxylic acid anhydride group, a carboxylic acid ester group, a hydroxyl group, an epoxy group, an amide group, an ammonium group, a nitrile group, an amino group, an imide group, and an isocyanate group. group, acetyl group, thiol group, ether group, thioether group, sulfone group, phosphon group, nitro group, urethane group, halogen atom, alkoxysilyl and the like.

Binder resin (A) is preferably a modified resin. The modified resin is a resin into which a reactive functional group is introduced, which is obtained by modifying a resin as a precursor using a modifying agent.
A modifier used for modifying the binder resin is a compound having a reactive functional group in the molecule. Reactive functional groups include those previously described.

Examples of modified resins include resins into which acid groups have been introduced (acid-modified resins) and resins into which hydroxyl groups have been introduced, and acid-modified resins are preferred. Among the acid-modified resins, resins into which an acid anhydride structure is introduced are preferable.
By using an acid-modified resin as the component (A), it becomes easier to obtain a curable adhesive composition that gives a cured product with excellent low dielectric properties. Furthermore, by using a resin into which an acid anhydride structure is introduced as the acid-modified resin, there is a tendency to easily maintain a long pot life.

In the case of a curable adhesive composition in which the component (A) is an acid-modified resin, the curable adhesive composition may contain other binder resins other than the acid-modified resin as other components.
In the curable adhesive composition, the content of the other binder resin is preferably 0 to 50 parts by mass, more preferably 0 to 30 parts by mass, and still more preferably 100 parts by mass of the total amount of the acid-modified resin. 0 to 10 parts by weight, more preferably 0 to 5 parts by weight.

As the acid-modified resin, for example, a resin is reacted with an unsaturated carboxylic acid or an unsaturated carboxylic anhydride (hereinafter sometimes referred to as "unsaturated carboxylic acid or the like") to form a carboxy group or a carboxylic anhydride group. is introduced (graft modification).

Unsaturated carboxylic acids to be reacted with the resin include unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, and aconitic acid; maleic anhydride, itaconic anhydride, and glutaconic anhydride. acids, unsaturated carboxylic anhydrides such as citraconic anhydride, aconitic anhydride, norbornene dicarboxylic anhydride, and tetrahydrophthalic anhydride;
These can be used individually by 1 type or in combination of 2 or more types. Among these, maleic anhydride is preferable because it is easy to obtain a curable adhesive composition that gives a cured product with higher adhesive strength.

The amount of the unsaturated carboxylic acid or the like to be reacted with the resin is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 3 parts by mass, and still more preferably 0.2 to 1 part by mass with respect to 100 parts by mass of the resin. part by mass. By curing the curable adhesive composition containing the acid-modified resin thus obtained, it becomes easier to obtain a cured product with higher adhesive strength.

The method of introducing unsaturated carboxylic acid units or unsaturated carboxylic anhydride units into the resin is not particularly limited. For example, in the presence of a radical generator such as organic peroxides or azonitriles, a resin and an unsaturated carboxylic acid, etc., a method of heating and melting above the melting point of the resin to react, or a method of reacting the resin and the unsaturated carboxylic acid. After dissolving an acid or the like in an organic solvent, the resin is graft-copolymerized with an unsaturated carboxylic acid or the like by heating and stirring in the presence of a radical generator.

As the binder resin (A), a modified polyolefin resin is preferable, and an acid-modified polyolefin resin is more preferable. When the binder resin (A) is an acid-modified polyolefin resin, it becomes easier to obtain a curable adhesive composition that gives a cured product with excellent low dielectric properties and low staining properties.

A modified polyolefin resin is a polyolefin resin into which a reactive functional group has been introduced, obtained by modifying a polyolefin resin as a precursor using a modifier.

In the case of a curable adhesive composition in which the component (A) is an acid-modified polyolefin resin, the curable adhesive composition contains, as another component, a binder resin other than the acid-modified polyolefin resin. may
In the curable adhesive composition, the content of the other binder resin is preferably 0 to 50 parts by mass, more preferably 0 to 30 parts by mass, and more preferably 0 to 30 parts by mass, based on 100 parts by mass of the total amount of the acid-modified polyolefin resin. It is preferably 0 to 10 parts by weight, and more preferably 0 to 5 parts by weight.

[Component (B): a cross-linking agent having a molecular weight of 1000 or less, which can react with the component (A)]
The curable adhesive composition of the present invention contains, as the component (B), a cross-linking agent having a molecular weight of 1,000 or less that can react with the component (A) (hereinafter sometimes referred to as "cross-linking agent (B)". ).
Since the curable adhesive composition of the present invention contains the cross-linking agent (B), contamination of the surroundings during the adhesion process can be suppressed, as will be described later.
In addition, a crosslinking agent (B) can be used individually by 1 type or in combination of 2 or more types.

The molecular weight of the cross-linking agent (B) is 1000 or less, preferably 800 or less, more preferably 700 or less, even more preferably 600 or less, and even more preferably 500 or less.
When the molecular weight of the cross-linking agent (B) is 1000 or less, the collision probability of the reaction with the component (A) is increased, the cross-linked structure is easily formed, and the curable adhesive is highly effective in suppressing the surrounding contamination in the adhesion process. agent composition.
Although there is no particular lower limit for the molecular weight of the cross-linking agent (B), it is usually 100 or more, preferably 200 or more.
The molecular weight of the cross-linking agent (B) is a formula weight determined from the structural formula of the compound used as the cross-linking agent (B).

The content of the cross-linking agent (B) (the total amount of these when two or more cross-linking agents (B) are included) is 0 with respect to the total amount (100% by mass) of the active ingredients of the curable adhesive composition. .1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, even more preferably 0.7% by mass or more, and particularly preferably is 0.9% by mass or more, and is preferably 5% by mass or less, more preferably 4% by mass or less, even more preferably 3% by mass or less, and even more preferably 2% by mass or less.
When the content of the cross-linking agent (B) is 0.1% by mass or more relative to the total amount of active ingredients in the curable adhesive composition, it is possible to obtain a curable adhesive composition that does not easily stain the surroundings. .
In addition, the content of the cross-linking agent (B) is 5% by mass or less with respect to the total amount of active ingredients in the curable adhesive composition, so that the curable adhesive composition gives a cured product having excellent low dielectric properties. easier to obtain.

The content of the cross-linking agent (B) (the total amount of these when two or more cross-linking agents (B) are included) is preferably 0.1 part by mass or more, more preferably 100 parts by mass of component (A) 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, still more preferably 0.8 parts by mass or more, particularly preferably 1.2 parts by mass or more, and preferably 10 parts by mass or less, more It is preferably 7 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less.

Cross-linking agent (B) is a compound capable of reacting with component (A). Therefore, as the cross-linking agent (B), it is necessary to appropriately select one having a reactive group or a reactive site that is reactive with the reactive functional group in the binder resin (A).
For example, as the cross-linking agent (B), an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, a metal chelate-based cross-linking agent, an aziridine-based cross-linking agent, or the like can be used. Among these, one or more selected from isocyanate-based cross-linking agents, epoxy-based cross-linking agents, and metal chelate-based cross-linking agents are preferable from the viewpoint of storage stability.
Further, in one aspect of the present invention, for example, when the binder resin (A) is an acid-modified resin and the reactive functional group in the binder resin (A) is a carboxy group or a carboxylic anhydride group, a cross-linking agent ( B) is preferably one or more selected from isocyanate-based cross-linking agents, epoxy-based cross-linking agents, and metal chelate-based cross-linking agents.

An isocyanate-based cross-linking agent is a compound having two or more isocyanate groups in the molecule.
Examples of isocyanate cross-linking agents include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, 1,5-pentamethylene diisocyanate, and 1,6-hexamethylene. Diisocyanate, diphenylmethane-4,4-diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, tetramethylxylylene diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, and polyisocyanate compounds thereof and adducts of polyol compounds such as trimethylolpropane, burettes and isocyanurates of these polyisocyanate compounds, and the like.

An epoxy-based cross-linking agent is a compound having two or more epoxy groups in its molecule.
Epoxy crosslinking agents include 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-m-xylylenediamine, ethylene glycol diglycidyl ether, 1 ,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidylaniline, diglycidylamine and the like.

A metal chelate-based cross-linking agent is a chelate compound having metal ions functioning as cross-linking points.
As metal chelate-based cross-linking agents, for example, metal chelate compounds whose metal ions are aluminum ions, zirconium ions, titanium ions, zinc ions, iron ions, tin ions, and the like can be used. Among these, aluminum chelate compounds are preferred.

Examples of aluminum chelate compounds include aluminum tris(acetylacetonate), acetylacetonate aluminum bis(ethylacetoacetate), diisopropoxyaluminum monooleyl acetoacetate, monoisopropoxyaluminum bisoleyl acetoacetate, and the like.

In one aspect of the present invention, the cross-linking agent (B) is preferably a compound having an isocyanurate skeleton, more preferably a compound having an isocyanurate skeleton and two or more isocyanate groups.
When the cross-linking agent (B) is a compound having an isocyanurate skeleton, it becomes easier to obtain a curable adhesive composition that gives a cured product with excellent low dielectric properties.
When the component (B) is a curable adhesive composition that is a compound having an isocyanurate skeleton, the curable adhesive composition contains, as another component, a cross-linking compound other than the compound having an isocyanurate skeleton. It may contain an agent.
In the curable adhesive composition, the content of the other cross-linking agent is preferably 0 to 100 parts by mass, more preferably 0 to 50 parts by mass, with respect to 100 parts by mass of the total amount of the compound having an isocyanurate skeleton. More preferably 0 to 30 parts by mass, still more preferably 0 to 10 parts by mass, and particularly preferably 0 to 5 parts by mass.

In one aspect of the present invention, a curable adhesive composition that gives a cured product having excellent low dielectric properties can be easily obtained. is preferred, and an isocyanurate of a polyisocyanate compound is more preferred, and an isocyanurate of 1,5-pentamethylene diisocyanate [1,3,5-tris(5-isocyanatopentyl)-1,3,5-triazine-2, 4,6-trione] or isocyanurate of 1,6-hexamethylene diisocyanate [1,3,5-tris(6-isocyanatohexyl)-1,3,5-triazine-2,4,6-trione] More preferred.
In the case of a curable adhesive composition in which the component (B) is an isocyanate-based cross-linking agent, the curable adhesive composition contains, as another component, a cross-linking agent other than the isocyanate-based cross-linking agent. You may
In the curable adhesive composition, the content of the other cross-linking agent is preferably 0 to 100 parts by mass, more preferably 0 to 50 parts by mass, with respect to 100 parts by mass of the total amount of the isocyanate-based cross-linking agent. It is preferably 0 to 30 parts by mass, more preferably 0 to 10 parts by mass, and particularly preferably 0 to 5 parts by mass.

In one aspect of the present invention, the cross-linking agent (B) is preferably an epoxy-based cross-linking agent, since a curable adhesive composition capable of suppressing contamination of the surroundings in the bonding process can be easily obtained.
In the case of a curable adhesive composition in which the component (B) is an epoxy-based cross-linking agent, the curable adhesive composition may contain, as another component, a cross-linking agent other than the epoxy-based cross-linking agent. good.
In the curable adhesive composition, the content of the other cross-linking agent is preferably 0 to 100 parts by mass, more preferably 0 to 50 parts by mass, and still more preferably 100 parts by mass of the total epoxy cross-linking agent. is 0 to 30 parts by weight, more preferably 0 to 10 parts by weight, and particularly preferably 0 to 5 parts by weight.

Since the cross-linking agent (B) is a compound that can react with the binder resin (A), the binder resin (A) and the cross-linking agent ( B) can be reacted to build a crosslinked structure in the coating film. A coating film having a crosslinked structure inside is difficult to fluidize even when heated. Therefore, by building a cross-linked structure in the coating film before adhering the two adherends, even if heat treatment is performed when adhering the two adherends, staining of the adhesive component in the coating film can be prevented. The coating film can be completely cured while suppressing extrusion.
As described above, in the curable adhesive composition of the present invention, by appropriately controlling the reaction between the binder resin (A) and the cross-linking agent (B), contamination of the surroundings during the adhesion process can be suppressed. .

[Component (C): non-aromatic curable compound that is liquid at 25°C]
Component (C) is a non-aromatic curable compound that is liquid at 25° C. (hereinafter sometimes referred to as “curable compound (C)”).
Curable compound (C) can be used individually by 1 type or in combination of 2 or more types.

The curable compound (C) is a curable compound. Therefore, when the curable compound (C) is the curable component (X) that does not participate in the curing reaction (I), the curable adhesive composition containing the curable compound (C) causes the curing reaction (I). The resulting cured product can undergo curing reaction (II) and can function as a solid adhesive.

The curable compound (C) is a compound that is liquid at 25°C. Therefore, when the curable compound (C) is the curable component (X) that does not participate in the curing reaction (I), the curable adhesive composition containing the curable compound (C) causes the curing reaction (I). The solid adhesive composed of the resulting cured product has good wettability and spreadability during lamination processing, and is more excellent in lamination aptitude.
"Liquid at 25°C" means having fluidity at 25°C. For example, a compound that is liquid at 25° C. is a compound with a viscosity of 2 to 10000 mPa·s measured at 25° C. and 1.0 rpm using an E-type viscometer.

The curable compound (C) is a non-aromatic compound. A non-aromatic compound means a compound without an aromatic ring. Since the curable compound (C) is a non-aromatic compound, the cured product of the curable adhesive composition containing the curable compound (C) tends to have excellent low dielectric properties.

The curable compound (C) is preferably a compound having a heterocyclic skeleton. When the curable compound (C) is a compound having a heterocyclic skeleton, it becomes easier to obtain a curable adhesive composition that gives a cured product with excellent adhesive strength and low dielectric properties.
When the component (C) is a curable adhesive composition that is a compound having a heterocyclic skeleton, the curable adhesive composition contains, as another component, a curable compound other than the compound having the heterocyclic skeleton. It may contain a compound.
In the curable adhesive composition, the content of the other curable compound is preferably 0 to 50 parts by mass, more preferably 0 to 30 parts by mass, relative to 100 parts by mass of the total amount of the compound having a heterocyclic skeleton. parts, more preferably 0 to 10 parts by weight, and even more preferably 0 to 5 parts by weight.
The heterocyclic skeleton includes an isocyanurate skeleton and a glycoluril skeleton.
The heterocyclic skeleton preferably has an n-fold rotation axis as a symmetry element. A cured product of a curable adhesive composition containing such a curable compound (C) having a heterocyclic skeleton tends to have excellent low dielectric properties.

The molecular weight of the curable compound (C) is preferably 1,000 or less, more preferably 800 or less, still more preferably 650 or less, and even more preferably 500 or less.
Curable compounds with a molecular weight of 1,000 or less tend to meet the requirement of being liquid at 25°C.
Moreover, the molecular weight of the curable compound (C) is preferably 100 or more, more preferably 200 or more, and even more preferably 275 or more.
The curable compound (C) having a molecular weight of 100 or more is less likely to volatilize during the drying process and heat curing process of the curable adhesive composition, so that a cured product having desired physical properties can be easily obtained.

As the curable compound (C), for example, a compound having two or more hydrocarbon groups having double bonds at the terminals (hereinafter, this compound may be referred to as "curable compound (C')"). mentioned.
By using the curable compound (C′) as the curable compound (C), it becomes easier to obtain a curable adhesive composition that gives a cured product having excellent low dielectric properties.
(C) When the component is the curable compound (C'), the curable adhesive composition contains, as other components, other than the curable compound (C') may contain a curable compound.
In the curable adhesive composition, the content of the other curable compound is preferably 0 to 50 parts by mass, more preferably 0 to 30 parts by mass, relative to 100 parts by mass of the curable compound (C'). parts by weight, more preferably 0 to 10 parts by weight, and even more preferably 0 to 5 parts by weight.

The number of carbon atoms in the hydrocarbon group having a double bond at the end contained in the curable compound (C') is preferably 2-10, more preferably 2-5.
Hydrocarbon groups having a double bond at the end include vinyl group, allyl group, 3-butenyl group, 4-pentenyl group, 5-hexenyl group, isopropenyl group, 1-methyl-2-propenyl group and vinylbenzyl group. , a vinyl naphthyl group, and the like. Among these, an allyl group is preferred.

The number of hydrocarbon groups having a double bond at the terminal contained in the curable compound (C') is two or more. When the number of hydrocarbon groups having a double bond at the terminal is 2 or more, it becomes easier to obtain a curable adhesive composition that gives a cured product with excellent adhesive strength and heat resistance.
In addition, when the crosslinked structure formed in the cured product is moderately sparse, the occurrence of cracks in the cured product tends to be suppressed. Therefore, the number of hydrocarbon groups having a double bond at the end is preferably 2-4, more preferably 2.

Examples of the curable compound (C') include a curable compound (C') having an isocyanurate skeleton and a curable compound (C') having a glycoluril skeleton.
Examples of the curable compound (C') having an isocyanurate skeleton include compounds represented by the following formula (1) or (2).

In formula (1), R ¹ and R ² each independently represent a hydrocarbon group having a double bond at the end; R ³ is a saturated hydrocarbon group having 1 to 15 carbon atoms; represents an alkoxy group-substituted alkyl group.
In formula (2), R ⁴ to R ⁶ each independently represent a hydrocarbon group having a double bond at its end.

The hydrocarbon groups having a double bond at the end represented by R ¹ , R ² , R ⁴ , R ⁵ and R ⁶ are as explained above.

The saturated hydrocarbon group represented by R ³ has 1 to 15 carbon atoms, preferably 5 to 15 carbon atoms, and more preferably 8 to 15 carbon atoms. Examples of saturated hydrocarbon groups represented by R ³ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, s-butyl group, isobutyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, etc. is mentioned.

The alkoxy group-substituted alkyl group represented by R ³ has 2 to 15 carbon atoms, preferably 2 to 12 carbon atoms, and more preferably 3 to 10 carbon atoms. The alkoxy-substituted alkyl group represented by R ³ includes methoxymethyl group, ethoxymethyl group, 2-methoxyethoxymethyl group, benzyloxymethyl group and the like.

Examples of the curable compound (C') having a glycoluril skeleton include compounds represented by the following formula (3).

In formula (3), R ⁷ to R ¹⁰ each independently represent a hydrocarbon group having 1 to 15 carbon atoms, at least two of which are hydrocarbon groups having double bonds at their ends. R ¹¹ and R ¹² each represent a hydrogen atom or a saturated hydrocarbon group having 1 to 15 carbon atoms.

Among these, a compound having an isocyanurate skeleton is preferable as the curable compound (C′), since a cured product having an appropriate crosslink density and excellent low dielectric properties can be easily obtained. A compound represented by is more preferable, and a compound represented by the following formula is even more preferable.

In the formula, R represents a saturated hydrocarbon group having 5 to 15 carbon atoms, preferably a saturated hydrocarbon group having 8 to 15 carbon atoms.

When the curable adhesive composition of the present invention contains the curable compound (C), the content of the curable compound (C) (the total amount when two or more curable compounds (C) are included) is preferably 5% by mass or more, more preferably 7% by mass or more, still more preferably 8.5% by mass or more, relative to the total amount (100% by mass) of the active ingredients of the curable adhesive composition, and , preferably 25% by mass or less, more preferably 20% by mass or less, and still more preferably 15% by mass or less.
When the content of the curable compound (C) is 5% by mass or more based on the total amount of active ingredients in the curable adhesive composition, it becomes easier to obtain a curable adhesive composition that provides a cured product with excellent adhesive strength. .
When the content of the curable compound (C) is 25% by mass or less in the total amount of active ingredients in the curable adhesive composition, it is easy to obtain a curable adhesive composition that gives a cured product having excellent low dielectric properties. Become.

When the curable adhesive composition of the present invention contains the curable compound (C), the content of the curable compound (C) (two or more curable compounds (C) The total amount of these when containing) is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, still more preferably 7 parts by mass or more, still more preferably 10 parts by mass or more, and preferably 30 It is not more than 25 parts by mass, more preferably not more than 20 parts by mass, and even more preferably not more than 16 parts by mass.

[(D) component: polyphenylene ether resin having a reactive functional group]
Component (D) is a polyphenylene ether resin having a reactive functional group (hereinafter sometimes referred to as "polyphenylene ether resin (D)").
A polyphenylene ether resin is a resin having a polyphenylene skeleton in its main chain.
A polyphenylene skeleton refers to a skeleton having a repeating unit represented by the following formula or a repeating unit in which hydrogen atoms in the above formula are substituted.

Polyphenylene ether resin (D) is a compound having a polyphenylene ether skeleton and a reactive functional group.
Since the polyphenylene ether resin (D) has a polyphenylene ether skeleton, the cured product of the curable adhesive composition containing the polyphenylene ether resin (D) is excellent in low dielectric properties.
Moreover, since the polyphenylene ether resin (D) has a reactive functional group, the cured product of the curable adhesive composition containing the polyphenylene ether resin (D) has excellent heat resistance.
Polyphenylene ether resin (D) can be used individually by 1 type or in combination of 2 or more types.

Examples of the polyphenylene ether skeleton in the polyphenylene ether resin (D) include those represented by the following formula (4).

In formula (4), X is a divalent group represented by the following formula (5) or formula (6), and each Y is independently a divalent group represented by the following formula (7) is a group, a and b are integers of 0 to 100, and at least one of a and b is 1 or more. * represents a bond (same below).

In formula (5), R ¹³ to R ²⁰ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group, preferably a hydrogen atom or a methyl group.

In formula (6), R ²¹ to R ²⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group, preferably a hydrogen atom or a methyl group. A represents a linear, branched or cyclic divalent hydrocarbon group having 20 or less carbon atoms.

In formula (7), R ²⁹ to R ³² each independently represent a hydrogen atom, a halogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group, preferably a hydrogen atom or a methyl group.

Examples of the polyphenylene ether skeleton in the polyphenylene ether resin (D) include those represented by the following formula (8).

(a and b are integers from 0 to 100, and at least one of a and b is 1 or more.)

Examples of reactive functional groups in the polyphenylene ether resin (D) include groups having an ethylenically unsaturated bond such as vinyl, allyl, acryloyl, methacryloyl, cyclopentenyl, vinylbenzyl, and vinylnaphthyl; group; hydroxyl group; and the like.
Among these, the reactive functional group is preferably a group having an ethylenically unsaturated bond, more preferably a vinylbenzyl group, since a cured product having excellent low dielectric properties can be easily obtained.

As the polyphenylene ether resin (D), a resin having a reactive functional group at both ends of the polyphenylene ether skeleton is preferable because a cured product having excellent low dielectric properties can be easily obtained.
(D) When the component is a curable adhesive composition that is a resin having a reactive functional group at both ends of the polyphenylene ether skeleton, the curable adhesive composition contains, as another component, the polyphenylene ether skeleton Other polyphenylene ether resins other than resins having reactive functional groups at both ends may be contained.
In the curable adhesive composition, the content of the other polyphenylene ether resin is preferably 0 to 50 parts by mass with respect to 100 parts by mass of the total amount of the resin having reactive functional groups at both ends of the polyphenylene ether skeleton. , more preferably 0 to 30 parts by mass, still more preferably 0 to 10 parts by mass, and even more preferably 0 to 5 parts by mass.

The polyphenylene ether resin (D) can be obtained by forming a polyphenylene ether skeleton and then introducing a reactive functional group to the terminal.
For example, a polyphenylene ether resin (D) having vinylbenzyl groups at both ends as reactive functional groups was reacted with a bifunctional phenol compound and a monofunctional phenol compound to obtain a polymer having phenolic hydroxyl groups at both ends. Then, it can be obtained by vinylbenzyl etherifying the terminal phenolic hydroxyl group using 4-(chloromethyl)styrene.

Examples of the polyphenylene ether resin (D) include compounds represented by the following formula (9).

(In the above formula, a and b are integers of 0 to 100, and at least one of a and b is 1 or more.)

(D) When a curable adhesive composition is a compound represented by the above formula (9), the curable adhesive composition is represented by the above formula (9) as another component. A polyphenylene ether resin other than the compound may be contained.
In the curable adhesive composition, the content of the other polyphenylene ether resin is preferably 0 to 50 parts by mass, more preferably 0 parts by mass, relative to 100 parts by mass of the total amount of the compound represented by the above formula (9). to 30 parts by mass, more preferably 0 to 10 parts by mass, and even more preferably 0 to 5 parts by mass.

The number average molecular weight (Mn) of the polyphenylene ether resin (D) is preferably 500 to 5,000, more preferably 500 to 3,000, still more preferably 700 to 2,500, still more preferably 1,000 to 2. , 000.
The number average molecular weight (Mn) of the polyphenylene ether resin (D) is obtained by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent, and can be obtained as a standard polystyrene conversion value, and specific measurement conditions is as described above.

When the curable adhesive composition of the present invention contains a polyphenylene ether resin (D), the content of the polyphenylene ether resin (D) (when two or more (D) components are included, the total amount of these) is Preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, still more preferably 15% by mass, relative to the total amount (100% by mass) of the active ingredients in the curable adhesive composition or more, preferably 30% by mass or less, more preferably 25% by mass or less.
When the content of the polyphenylene ether resin (D) is 1% by mass or more in the total amount of active ingredients of the curable adhesive composition, it is easy to obtain a curable adhesive composition that gives a cured product having excellent low dielectric properties. Become.
When the content of the polyphenylene ether resin (D) is 30% by mass or less in the total amount of active ingredients of the curable adhesive composition, it becomes easier to impart sticking properties.

When the curable adhesive composition of the present invention contains the polyphenylene ether resin (D), the content of the polyphenylene ether resin (D) relative to 100 parts by mass of the component (A) (including two or more components (D) When the total amount of these) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 15 parts by mass or more, still more preferably 20 parts by mass or more, and preferably 50 parts by mass Below, more preferably 40 parts by mass or less, still more preferably 35 parts by mass or less, and even more preferably 30 parts by mass or less.

[(F) component: silane coupling agent]
The curable adhesive composition of the present invention may contain a silane coupling agent (F) as a curable component (X).
The silane coupling agents (F) can be used singly or in combination of two or more.

A known silane coupling agent can be used as the silane coupling agent (F). Among them, organosilicon compounds having at least one alkoxysilyl group in the molecule are preferred.
Silane coupling agents (F) include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyl Silane coupling agents having a (meth)acryloyl group such as roxypropyltrimethoxysilane;
Silane coupling agents having a vinyl group such as vinyltrimethoxysilane, vinyltriethoxysilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, trichlorovinylsilane, vinyltris(2-methoxyethoxy)silane;
2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 8-glycid Silane coupling agents having an epoxy group such as xyoctyltrimethoxysilane;
Silane coupling agents having a styryl group such as p-styryltrimethoxysilane and p-styryltriethoxysilane;
N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane , 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N - Silane coupling agents having an amino group such as hydrochloride of (vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane;
Silane coupling agents having a ureido group such as 3-ureidopropyltrimethoxysilane and 3-ureidopropyltriethoxysilane;
Silane coupling agents having halogen atoms such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane;
Silane coupling agents having a mercapto group such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane;
Silane coupling agents having a sulfide group such as bis(trimethoxysilylpropyl)tetrasulfide and bis(triethoxysilylpropyl)tetrasulfide;
Silane coupling agents having an isocyanate group such as 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane;
Silane coupling agents having an allyl group such as allyltrichlorosilane, allyltriethoxysilane, allyltrimethoxysilane;
silane coupling agents having a hydroxyl group such as 3-hydroxypropyltrimethoxysilane and 3-hydroxypropyltriethoxysilane;

When the curable adhesive composition contains a silane coupling agent (F), the content of the silane coupling agent (F) (when two or more silane coupling agents (F) are included, the total amount of these) is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.08% by mass or more, relative to the total amount (100% by mass) of the active ingredients of the curable adhesive composition and is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, and even more preferably 0.5% by mass or less.
When the content of the silane coupling agent (F) is 0.01% by mass or more based on the total amount of active ingredients in the curable adhesive composition, it becomes easier to maintain the adhesiveness after the high-temperature and high-humidity test.
When the content of the silane coupling agent (F) is 5% by mass or less in the total amount of active ingredients in the curable adhesive composition, it becomes easier to maintain the adhesiveness after the high temperature and high humidity test.

When the curable adhesive composition of the present invention contains a silane coupling agent (F), the content of the silane coupling agent (F) (two or more silane coupling agents The total amount of these when containing (F)) is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, still more preferably 0.1 parts by mass or more, and even more preferably 0.15 It is at least 3 parts by mass, preferably 3 parts by mass or less, more preferably 1 part by mass or less, still more preferably 0.7 parts by mass or less, and even more preferably 0.5 parts by mass or less.

[(E) component: cationic polymerization initiator]
The curable adhesive composition of the present invention may contain a cationic polymerization initiator as component (E).
When curing reaction (I) or curing reaction (II) is a cationic polymerization reaction, these curing reactions can be efficiently advanced by adding a cationic polymerization initiator to the curable adhesive composition.
A cationic polymerization initiator can be used individually by 1 type or in combination of 2 or more types.
Examples of the cationic polymerization initiator (E) include thermal cationic polymerization initiators and photocationic polymerization initiators, and preferred are thermal cationic polymerization initiators that can be polymerized by a simple process.

Thermal cationic polymerization initiators are compounds that can generate cationic species that initiate polymerization upon heating.
Thermal cationic polymerization initiators include sulfonium salts, quaternary ammonium salts, phosphonium salts, diazonium salts, iodonium salts and the like.

Sulfonium salts include triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluoroalcinate, tris(4-methoxyphenyl)sulfonium hexafluoroalcinate, and diphenyl(4-phenylthiophenyl)sulfonium. hexafluoroalcinate and the like.

The quaternary ammonium salts include tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, tetrabutylammonium hydrogensulfate, tetraethylammonium tetrafluoroborate, tetraethylammonium p-toluenesulfonate, N,N-dimethyl-N- benzylanilinium hexafluoroantimonate, N,N-dimethyl-N-benzylanilinium tetrafluoroborate, N,N-dimethyl-N-benzylpyridinium hexafluoroantimonate, N,N-diethyl-N-benzyltrifluoromethanesulfonate , N,N-dimethyl-N-(4-methoxybenzyl)pyridinium hexafluoroantimonate, N,N-diethyl-N-(4-methoxybenzyl)toluidinium hexafluoroantimonate, and the like.

Phosphonium salts include ethyltriphenylphosphonium hexafluoroantimonate, tetrabutylphosphonium hexafluoroantimonate, and the like.

Examples of iodonium salts include diphenyliodonium hexafluoroarsinate, bis(4-chlorophenyl)iodonium hexafluoroarsinate, bis(4-bromophenyl)iodonium hexafluoroarsinate, phenyl(4-methoxyphenyl)iodonium hexafluoroarsinate, and the like. is mentioned.

When the curable adhesive composition contains a cationic polymerization initiator (E), the content of the cationic polymerization initiator (E) (when two or more (E) components are included, the total amount of these) is a cationic Preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, still more preferably 0.1 parts by mass with respect to a total of 100 parts by mass of components (C) and (D), which are polymerizable compounds Above, more preferably 0.2 parts by mass or more, preferably 6 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 4 parts by mass or less.
When the content of the cationic polymerization initiator is 0.01 parts by mass or more, it becomes easier to prevent a decrease in reactivity.
When the content of the cationic polymerization initiator is 6 parts by mass or less, it becomes easy to suppress corrosion of the adherend.

〔solvent〕
The curable adhesive composition of the present invention may be in the form of a solution containing a solvent.
Examples of solvents include aromatic hydrocarbon solvents such as benzene and toluene; ester solvents such as ethyl acetate and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as heptane; alicyclic hydrocarbon solvents such as cyclopentane, cyclohexane, and methylcyclohexane; and the like.
These solvents can be used singly or in combination of two or more.
When the curable adhesive composition contains a solvent, the content of the solvent can be appropriately determined in consideration of applicability and the like.

[Other ingredients]
The curable adhesive composition of the present invention may contain components (other components) other than those described above as long as the effects of the present invention are not impaired.
Other components include additives such as UV absorbers, antistatic agents, light stabilizers, antioxidants, resin stabilizers, fillers, pigments, extenders and softeners.
These can be used individually by 1 type or in combination of 2 or more types.
When the curable adhesive composition of the present invention contains these additives, the content thereof can be appropriately determined according to the purpose.

[Method for Producing and Using Curable Adhesive Composition]
The curable adhesive composition of the present invention can be prepared by appropriately mixing and stirring the binder resin (A), the cross-linking agent (B), and other optional components according to a conventional method.

The method of using the curable adhesive composition of the present invention is not particularly limited.
For example, the curable adhesive composition of the present invention is applied to one adherend, the resulting coating film is dried, and the curing reaction (I) proceeds to form a cured product (I). Then, another adherend is superimposed on the cured product (I), and these adherends can be adhered by further curing the coating film.
As described above, when the curing reaction (I) started to build a crosslinked structure in the coating film is stopped in the middle, the unreacted binder resin (A) in the cured product (I) and the cross-linking agent (B) can be used to restart the curing reaction (I) to bond the two adherends together. Further, when the cured product (I) contains a curable component (X) that does not participate in the curing reaction (I), the curing reaction (II) can be used to bond two adherends together. .

Examples of methods for applying the curable adhesive composition include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating.

Methods for drying the coating film include conventionally known drying methods such as hot air drying, hot roll drying, and infrared irradiation.
The conditions for drying the coating film are, for example, 80 to 150° C. for 30 seconds to 5 minutes.

Although the thickness of the coating film is not particularly limited, it is usually 1 to 50 μm, preferably 1 to 25 μm, more preferably 5 to 25 μm.

When the curing reaction (I) is a reaction initiated by heat, the drying treatment of the coating film and the curing reaction (I) can be combined.
For example, the reactive functional group in the binder resin (A) is a carboxy group or a carboxylic anhydride group, and the cross-linking agent (B) is an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, a metal chelate-based cross-linking agent, or the like. In this case, by heating the coating film to about 100° C., the drying treatment and the curing reaction (I) can be performed simultaneously, and the cured product (I) can be obtained.

Alternatively, an adhesive sheet may be produced using the curable adhesive composition of the present invention, and two adherends may be bonded using this adhesive sheet.
For example, the curable adhesive composition of the present invention is applied on a release film, the resulting coating film is dried, and the curing reaction (I) is allowed to proceed to cure the cured product (I) (adhesion of the adhesive sheet). agent layer) can be obtained.
The method for applying the curable adhesive composition and the method for drying may be those described above.
In addition, the preferable thickness of the coating film and the combination of the drying treatment of the coating film and the curing reaction (I) are also as described above.

[Physical Properties of Cured Product Obtained from Curable Adhesive Composition]
The curable adhesive composition of the present invention provides a cured product having a dielectric loss tangent of less than 0.0050 at 23° C. and a frequency of 1 GHz by curing the curable adhesive composition, and 0.0030 or less. Those that give a cured product are preferred, those that give a cured product of 0.0020 or less are more preferred, those that give a cured product of 0.0015 or less are more preferred, those that give a cured product of 0.0012 or less are even more preferred, Those that give a cured product of 0.0010 or less are more preferred, and those that give a cured product of 0.0008 or less are particularly preferred. Although there is no particular lower limit for the dielectric loss tangent under these conditions, it is usually 0.0001 or more.

The curable adhesive composition of the present invention preferably gives a cured product having a dielectric constant of 3.00 or less at 23° C. and a frequency of 1 GHz by curing the curable adhesive composition, and preferably 2.75 or less. more preferably give a cured product of 2.50 or less. Although there is no particular lower limit for the dielectric constant under these conditions, it is usually 2.00 or more.

The cured state of the sample used for the measurement of the dielectric loss tangent and the dielectric constant is not limited as long as the measurement is possible. For example, it may or may not have additional curability.
An example of a sample for measurement of the dielectric loss tangent and relative permittivity is a sheet-like adhesive after being subjected to a heat treatment at 100° C. for 2 minutes as a drying treatment and curing reaction (I).

The curable adhesive composition of the present invention provides a cured product having the above-described dielectric properties through a curing reaction. It is preferably used as a material for forming members, insulating members, and the like.

(2) Cured Product The cured product of the present invention is characterized in that the raw material composition is the curable adhesive composition of the present invention.
That is, the cured product of the present invention is a product in which at least the curing reaction (I) proceeds and the viscosity of the curable adhesive composition increases or solidifies.

Examples of the cured product of the present invention include the following.
Cured product (α1): A cured product whose raw material composition is a curable adhesive composition capable of performing only curing reaction (I) as a curing reaction, wherein the curing reaction (I) is interrupted in the middle and further curability is obtained. Cured product Cured product (β1): A cured product whose raw material composition is a curable adhesive composition capable of performing curing reaction (I) and curing reaction (II) as a curing reaction, at least curing reaction (II Cured product having curability derived from ) Cured product (α2): A cured product whose raw material composition is a curable adhesive composition capable of performing only the curing reaction (I) as a curing reaction, wherein the curing reaction (I ) is completed and does not have further curability. A cured product in which the curing reaction (I) and the curing reaction (II) are completed and have no further curability

The cured product (α1) and the cured product (β1) are cured products having curability. The cured product (α1) and cured product (β1) are useful as solid adhesives. It is preferable that these hardened products have thermosetting properties because the bonding process can be performed efficiently.
Further, the thermosetting cured product preferably has a sheet-like shape.
Since the thermosetting cured product has a sheet-like shape, two adherends can be efficiently adhered by heat press treatment or the like.

Sheet-shaped thermosetting cured products (hereinafter sometimes referred to as "thermosetting sheet adhesives") are protected on one or both sides for protection during storage and transportation. It may have a seat or the like.

The thermosetting sheet adhesive of the present invention uses the curable adhesive composition of the present invention as a raw material composition. Therefore, the cured product obtained by curing the thermosetting sheet adhesive of the present invention is excellent in low dielectric properties.
Therefore, the thermosetting sheet-like adhesive of the present invention is suitably used as a sheet-like adhesive for electronic devices and a sheet-like adhesive for coverlay films.

Sheet-like adhesives for electronic devices are sheet-like adhesives used for bonding various parts in electronic devices and for protecting and insulating circuits in electronic devices.
Examples of electronic devices include communication devices such as smartphones and tablet terminals.

A sheet-like adhesive for a coverlay film is a sheet-like adhesive used when manufacturing a coverlay film. A coverlay film is, for example, a laminated film used to protect the surface of a flexible printed wiring board, and usually has an insulating resin layer and an adhesive layer.
The thermosetting sheet adhesive of the present invention is useful as this adhesive layer.

The cured product (α2) and the cured product (β2) are non-curing products. As the cured product (α2) and the cured product (β2), the cured product (α1) and the cured product (β1) function as an adhesive and are in a completely cured state, or the curable adhesive composition of the present invention. Examples include a molded article obtained by completely curing an object.

The present invention will be described in more detail below with reference to examples. However, the present invention is by no means limited to the following examples.

[Compounds used in Examples or Comparative Examples]
- Binder resin (A1): maleic anhydride-modified α-olefin polymer [manufactured by Mitsui Chemicals, trade name: UNISTOL H-200, number average molecular weight: 47,000]
Isocyanate-based cross-linking agent (B1): 1,3,5-tris(5-isocyanatopentyl)-1,3,5-triazine-2,4,6-trione [manufactured by Mitsui Chemicals, Inc., trade name: Stabio D-370N, molecular weight: 462]
Epoxy-based cross-linking agent (B2): 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, [manufactured by Mitsubishi Gas Chemical Company, Inc., trade name: TETRAD-C, molecular weight: 362]
- Metal chelate-based cross-linking agent (B3): aluminum tris (acetylacetonate) [manufactured by Soken Chemical Co., Ltd., trade name: M-5A, molecular weight: 324]
Curable compound (C1): a compound having an isocyanurate skeleton and two allyl groups [manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name: L-DAIC]
- Polyphenylene ether resin (D1): vinylbenzyl-modified polyphenylene ether [manufactured by Mitsubishi Gas Chemical Company, trade name: OPE-2St 1200, number average molecular weight: 1200]
- Cationic polymerization initiator (E1): Thermal cationic polymerization initiator [manufactured by Sanshin Chemical Industry Co., Ltd., product name: San-Aid SI-B3]
- Silane coupling agent (F1): 8-glycidoxyoctyltrimethoxysilane [manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM4803]

[Example 1]
Binder resin (A1) 100 parts by mass, isocyanate cross-linking agent (B1) 0.5 parts by mass, curable compound (C1) 12.5 parts by mass, polyphenylene ether resin (D1) 25 parts by mass, cationic polymerization initiator (E1) 0.12 parts by mass and 0.2 parts by mass of the silane coupling agent (F1) were dissolved in toluene to prepare a curable adhesive composition.
The obtained curable adhesive composition is applied on the release-treated surface of a release sheet (first release sheet, manufactured by Lintec Corporation, trade name: SP-PET752150) to form a coating film, and the resulting coating is The film was dried at 100° C. for 2 minutes to form an adhesive layer with a thickness of 15 μm. An adhesive sheet was obtained by laminating the release-treated surface of another release sheet (second release sheet, product name: SP-PET381130, manufactured by Lintec Corporation) on the exposed surface of the adhesive layer.

[Examples 2 to 5, Comparative Example 1]
A curable adhesive composition was prepared and an adhesive sheet was obtained in the same manner as in Example 1, except that the amounts or types of the components were changed to those shown in Table 1.

[Evaluation of exudation of ingredients]
One release sheet of the adhesive sheet obtained in Examples or Comparative Examples was peeled off, and the exposed adhesive layer was press-bonded to a polyimide film (Kapton, 25 μm thick, manufactured by DuPont-Toray Co., Ltd.) at 100° C. using a heat laminator. to obtain a laminate having a structure of release sheet/adhesive layer/polyimide film. Next, the release sheet of this laminate was peeled off, and the exposed adhesive layer was press-bonded to copper foil at 100° C. using a hot laminator to obtain a laminate having a structure of copper foil/adhesive layer/polyimide film. . Since the copper foil has a larger area than the other two layers, when the adhesive component of the adhesive layer seeps out, it adheres to the copper foil.
This laminate was subjected to a heat press treatment under conditions of 171° C. and 1.38 MPa for 20 minutes.
After cooling, the length of the most exuded adhesive component from the adhesive layer (cured product) in plan view [the length (μm) of the portion indicated by X in FIG. 1] was measured using a digital microscope. . The results are shown in Table 1. In addition, FIG. 1 is a schematic plan view of the laminated body used for evaluating the exudation of the adhesive component in the examples after being subjected to a heat press treatment. As shown in FIG. 1, a part of the adhesive layer (cured product) sandwiched between the copper foil 1 and the polyimide film 3 of the laminate oozes out and is deposited on the copper foil 1 by the heat press treatment. The exuded adhesive component 2 may adhere. At this time, as shown in FIG. 1, the maximum value X of the distance between the oozing adhesive component 2 and the polyimide film 3 when viewed from the top is defined as "the oozing length of the adhesive component", and is shown in Table 1. described.

[Dielectric constant, dielectric loss tangent]
After stacking a plurality of the adhesive layers of the adhesive sheets obtained in Examples or Comparative Examples so as to have a thickness of about 1 mm, a heat laminator is used to perform a fusion treatment at 100° C., resulting in a release sheet/about 1 mm thickness. A laminate having a structure of thick adhesive layer/release sheet was obtained. The release sheets on both sides of this laminate were peeled off to obtain a sample for measurement.
The dielectric constant and dielectric loss tangent at 23° C. and 1 GHz were measured using an RF impedance material analyzer (manufactured by Keysight Technologies, E4991A) for the obtained measurement sample. In addition, 1 GHz was adopted as an example of a high frequency region this time.
The results are shown in Table 1.

The cured products of the curable adhesive compositions obtained in Examples 1 to 5 and Comparative Example 1 are all excellent in low dielectric properties.
However, when a laminate was produced using the curable adhesive composition of Comparative Example 1, a heat press treatment was performed under the conditions of 171° C., 1.38 MPa, and 20 minutes, and the adhesive component oozed out to a large extent.
On the other hand, since the curable adhesive compositions of Examples 1 to 5 contain the cross-linking agent (B), the coating film of the curable adhesive composition was dried at 100°C or heat laminated at 100°C. A crosslinked structure is formed in the coating film by performing the treatment. Therefore, even if the heat press treatment is performed under the conditions of 171° C., 1.38 MPa, and 20 minutes, the exudation of the adhesive component is suppressed.

1: Copper foil 2: Exuded adhesive component 3: Polyimide film

Claims

A curable adhesive composition containing the following components (A) and (B), wherein the content of component (B) is 0.1% by mass or more relative to the total amount of active ingredients in the curable adhesive composition. being a thing,
A curable adhesive composition that, when cured, gives a cured product having a dielectric loss tangent of less than 0.0050 at 23° C. and a frequency of 1 GHz.
(A) component: binder resin having a reactive functional group (B) component: a cross-linking agent having a molecular weight of 1000 or less that can react with the component (A)
The curable adhesive composition according to claim 1, wherein the component (A) is a polyolefin resin.
The curable adhesive composition according to claim 1 or 2, wherein the component (A) is an acid-modified resin.
The curable adhesive composition according to any one of claims 1 to 3, wherein the component (B) is a compound having an isocyanurate skeleton.
The curable adhesive composition according to any one of claims 1 to 4, wherein the component (B) is a compound having two or more isocyanate groups.
The curable adhesive composition according to any one of claims 1 to 5, further comprising the following component (C).
Component (C): A non-aromatic curable compound that is liquid at 25°C
The curable adhesive composition according to claim 6, wherein the component (C) is a compound having two or more hydrocarbon groups with double bonds at their terminals.
The curable adhesive composition according to any one of claims 1 to 7, further comprising the following component (D).
(D) component: polyphenylene ether resin having a reactive functional group
The curable adhesive composition according to any one of claims 1 to 8, further comprising the following component (E).
(E) component: cationic polymerization initiator
The curable adhesive according to any one of claims 1 to 9, wherein the curable adhesive composition, when cured, gives a cured product having a dielectric constant of 3.00 or less at 23 ° C. and a frequency of 1 GHz. agent composition.
A cured product obtained by curing the curable adhesive composition according to any one of claims 1 to 10.
The cured product according to claim 11, wherein the cured product has thermosetting properties.
The cured product according to claim 11 or 12, wherein the cured product has a sheet-like shape.
The cured product according to any one of claims 11 to 13, wherein the cured product is a sheet adhesive for electronic devices.
The cured product according to any one of claims 11 to 13, wherein the cured product is a sheet adhesive for coverlay films.