WO2023106206A1

WO2023106206A1 - Layered body, adhesive agent composition, and circuit board material

Info

Publication number: WO2023106206A1
Application number: PCT/JP2022/044397
Authority: WO
Inventors: 菜摘向坂; 宇之中根
Original assignee: 三菱ケミカル株式会社
Priority date: 2021-12-06
Filing date: 2022-12-01
Publication date: 2023-06-15
Also published as: KR20240033256A; TW202330279A; JPWO2023106206A1

Abstract

This layered body has an adhesive layer on at least one surface of a base material or a conductor layer thereof. The adhesive layer is a cured product of an adhesive agent composition containing a polyester-based resin (A), a polyepoxy-based compound (B), and a filler (C). The dielectric loss tangent (Df) (in an environment where the temperature is 23ºC and a relative humidity is 50%RH) at 10 GHz of the adhesive layer is 0.005 or less.

Description

Laminates, adhesive compositions and circuit board materials

TECHNICAL FIELD The present invention relates to a laminate having an adhesive layer made of a cured adhesive composition containing a polyester resin. More specifically, the present invention relates to a laminate having an adhesive layer that is excellent in heat resistance, has a low dielectric loss tangent, and has a high adhesive strength retention rate before and after a wet heat durability test.
The invention also relates to a circuit board material comprising this laminate.
The present invention also relates to an adhesive composition suitable for the adhesive layer of this laminate.

Polyester-based resins are excellent in heat resistance, chemical resistance, durability, and mechanical strength, so they are used in a wide range of fields such as films, PET bottles, fibers, toners, electrical parts, adhesives, and adhesives. .
Polyester-based resins are highly polar due to their polymer structure, and are known to exhibit excellent adhesion to polar polymers such as polyester, polyvinyl chloride, polyimide, and epoxy resins, as well as metal materials such as copper and aluminum. It is Utilizing this property, polyester resins are being investigated for use as adhesives for producing laminates of metal and plastic.

Patent Literature 1 proposes a thermosetting adhesive sheet that is excellent in dimensional stability when cured and excellent in adhesiveness, heat resistance, flexibility, electrical insulation, low dielectric constant and low dielectric loss tangent after curing. . In this thermosetting adhesive sheet, the total amount of the reactive functional group capable of reacting with at least one of the organometallic compound and the epoxy group-containing compound and the functional group having a heteroatom other than halogen is 0.01 mmol/g. It is formed from a thermosetting composition containing 9 mmol/g or less resin (for example, polyester resin), an organometallic compound, and a trifunctional or higher epoxy group-containing compound.

Patent Document 2 proposes a copolyester having excellent wet heat resistance and cationic acid resistance, compatibility with epoxy resins, and adhesiveness, and an adhesive composition containing it. This copolymer polyester comprises an aromatic dicarboxylic acid component, a dimer diol, a first glycol, a second glycol or an oxyacid, and an alkylene glycol having 2 to 10 carbon atoms.

In Patent Document 3, an adhesive composition having excellent long-term durability in a moist heat environment and further having high adhesiveness has an ester bond concentration of 7 mmol / g or less, an acid value of 3 mgKOH / g or more, and a glass transition An adhesive composition containing a polyester resin (A1) satisfying the requirement that the temperature (Tg) is -5°C or higher has been proposed.

Japanese Patent Application Laid-Open No. 2017-031301 JP 2003-183365 A WO2021/079670

In recent years, in the field of electronic materials such as flexible copper-clad laminates and flexible printed circuit boards, the physical properties required for the adhesive layer used there include excellent adhesiveness, heat resistance, and durability to moisture and heat, as well as transmission signals. Along with the increase in the frequency of the radio frequency, low dielectric properties such as a lower dielectric constant and a lower dielectric loss tangent, especially a low dielectric loss tangent, are strongly desired.
However, when a resin is designed for the purpose of improving heat resistance and wet heat durability, the dielectric loss tangent tends to increase, and it has been difficult to achieve both of these characteristics at a high level.

For example, in the technology disclosed in Patent Document 1, a large amount of polyhydric carboxylic acid or polyhydric alcohol having a long-chain alkyl group is used for the purpose of lowering the dielectric constant, dielectric loss tangent, and water absorption, so adhesion is poor. There were problems such as lowering. Further, Patent Document 1 does not take into consideration the long-term durability in a hot and humid environment, and further improvement is required.

When a copper-clad laminate or the like is produced using the adhesive composition disclosed in Patent Document 2, it is assumed that the long-term durability in a moist and hot environment is relatively excellent. However, the copolymerized polyester contains an ether bond-containing glycol such as polypropylene glycol as a copolymerization component, or is not given an acid value that serves as a reaction point with the epoxy resin. For this reason, the copolyester has a problem that it is inferior in adhesiveness and heat resistance.

Although the adhesive composition disclosed in Patent Document 3 has solved these problems, further improvement in low dielectric loss tangent is desired.

The present invention is an adhesive composition that has excellent heat resistance, a low dielectric loss tangent, and can form an adhesive layer having a high adhesive strength maintenance rate before and after a wet heat durability test, and this adhesive composition. Laminates and circuit board materials are provided.

The present inventors have found that by controlling the dielectric loss tangent (Df) of a cured adhesive composition containing a polyester resin (A), a polyepoxy compound (B) and a filler (C), excellent heat resistance can be obtained. , contributed to low transmission loss, and obtained a laminate having a high adhesive force retention rate before and after the wet heat durability test.

The gist of the present invention is as follows.

[1] A laminate having an adhesive layer on at least one surface of a substrate or a conductor layer,
The adhesive layer is a cured product of an adhesive composition containing a polyester resin (A), a polyepoxy compound (B), and a filler (C),
A laminate in which the dielectric loss tangent (Df) of the adhesive layer at 10 GHz (at a temperature of 23° C. and a relative humidity of 50% RH) is 0.005 or less.

[2] The laminate according to [1], wherein the filler (C) contains fluoropolymer powder (C1) and/or clay mineral (C2).

[3] The content of the polyepoxy compound (B) in the adhesive composition is such that the epoxy equivalent of the polyepoxy compound (B) to the carboxy group of the polyester resin (A) is 0.8 or more 2 The laminate according to [1] or [2], which is less than the amount.

[4] The laminate according to any one of [1] to [3], wherein the polyester resin (A) has an acid value of 3 mgKOH/g or higher and a glass transition temperature of -5°C or higher.

[5] The laminate according to any one of [1] to [4], wherein the polyester resin (A) contains structural units derived from polycarboxylic acids and structural units derived from polyhydric alcohols.

[6] The laminate according to [5], wherein the polyester-based resin (A) contains a structural unit derived from an aromatic polycarboxylic acid as the structural unit derived from the polycarboxylic acid.

[7] Any one of [1] to [6], wherein the content of the filler (C) in the adhesive composition is 1 to 100 parts by weight with respect to 100 parts by weight of the polyester resin (A) The laminate according to .

[8] The base material is polyimide film, polyether ether ketone film, polyphenylene sulfide film, aramid film, polyethylene naphthalate film, liquid crystal polymer film, polyethylene terephthalate film, polyethylene film, polypropylene film, silicone release treated paper, polyolefin The laminate according to any one of [1] to [7], which is at least one selected from the group consisting of resin-coated paper, polymethylpentene film, and fluorine resin film.

[9] The laminate according to any one of [1] to [8], which is further laminated with a conductor.

[10] A circuit board material having the laminate according to any one of [1] to [9].

[11] An adhesive composition containing a polyester resin (A), a polyepoxy compound (B), and a filler (C),
An adhesive composition having a dielectric loss tangent (Df) at 10 GHz (at a temperature of 23° C. and a relative humidity of 50% RH) of 0.005 or less for a cured product of the adhesive composition.

[12] The adhesive composition according to [11], wherein the filler (C) contains fluoropolymer powder (C1) and/or clay mineral (C2).

[13] The content of the polyepoxy compound (B) is such that the epoxy equivalent of the polyepoxy compound (B) to the carboxy group of the polyester resin (A) is 0.8 or more and less than 2. , [11] or the adhesive composition according to [12]

[14] The adhesive composition according to any one of [11] to [13], wherein the polyester resin (A) has an acid value of 3 mgKOH/g or higher and a glass transition temperature of -5°C or higher.

[15] The adhesive composition according to [14], wherein the polyester resin (A) has an acid value of 5 mgKOH/g or higher and a glass transition temperature of -5°C or higher.

[16] The adhesive composition according to any one of [11] to [15], wherein the polyester resin (A) contains structural units derived from polycarboxylic acids and structural units derived from polyhydric alcohols. thing.

[17] The adhesive composition according to [16], wherein the polyester-based resin (A) contains a structural unit derived from an aromatic polycarboxylic acid as the structural unit derived from the polycarboxylic acid.

[18] The adhesive composition according to any one of [11] to [17], wherein the content of the filler (C) is 1 to 100 parts by weight with respect to 100 parts by weight of the polyester resin (A). thing.

The adhesive layer of the laminate of the present invention has excellent heat resistance, contributes to low transmission loss, and maintains a high adhesive strength before and after the wet heat durability test.
Moreover, according to the adhesive composition of the present invention, it is possible to form an adhesive layer which is excellent in heat resistance, contributes to low transmission loss, and has a high rate of maintaining adhesive strength before and after the wet heat durability test.

The laminate of the present invention is particularly suitable as a laminate obtained by bonding and integrating metal and plastic with an adhesive layer, for example, flexible laminates such as flexible copper-clad laminates and flexible printed circuit boards, coverlays, bonding sheets, and the like. Among them, it is more preferably used as a circuit board material such as a flexible printed wiring board. Such a circuit board material has excellent long-term durability and high reliability in a hot and humid environment.

The configuration of the present invention will be described in detail below. The following description provides an example of a preferred embodiment of the invention.

In the present invention, the "class" attached after the compound name is a concept that includes not only the compound but also derivatives of the compound. For example, the term "carboxylic acids" includes carboxylic acids as well as carboxylic acid derivatives such as carboxylic acid salts, carboxylic acid anhydrides, carboxylic acid halides, and carboxylic acid esters.

[Adhesive composition]
The adhesive composition of the present invention contains a polyester resin (A), an epoxy compound (B) and a filler (C), and its cured product exhibits a specific dielectric loss tangent (Df).

[Polyester resin (A)]
The polyester-based resin (A) preferably contains a structural unit derived from a polycarboxylic acid and a structural unit derived from a polyhydric alcohol in the molecule, and particularly preferably, an ester of a polyhydric carboxylic acid and a polyhydric alcohol. It is obtained by combining.

<Polyvalent carboxylic acids>
Polyvalent carboxylic acids in polyvalent carboxylic acids include, for example, aromatic polyvalent carboxylic acids described later; 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid and acid anhydrides thereof alicyclic polyvalent carboxylic acids such as polycarboxylic acids; and aliphatic polyvalent carboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid and dodecanedioic acid. 1 type(s) or 2 or more types can be used for polyhydric carboxylic acid.

The polyvalent carboxylic acid preferably contains an aromatic polyvalent carboxylic acid. Examples of aromatic polycarboxylic acids include monocyclic aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, dimethyl terephthalate, dimethyl isophthalate, and orthophthalic acid; biphenyldicarboxylic acid, naphthalenedicarboxylic acid, and naphthalenedicarboxylic acid; Polycyclic aromatic polycarboxylic acids such as dimethyl; Among polycyclic aromatic polycarboxylic acids, naphthalenedicarboxylic acid, condensed polycyclic aromatic polycarboxylic acids such as dimethyl naphthalenedicarboxylate, and these Derivatives (aromatic dicarboxylic acids) can be mentioned. Aromatic oxycarboxylic acids such as p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are also included.

Further, trifunctional or higher functional aromatic carboxylic acids introduced for the purpose of imparting a branched skeleton and acid value to the polyester resin (A) are also included in the above aromatic polyvalent carboxylic acids.
Examples of tri- or higher functional aromatic carboxylic acids include trimellitic acid, trimesic acid, ethylene glycol bis(anhydrotrimellitate), glycerol tris(anhydrotrimellitate), trimellitic anhydride, and pyromellitic acid. dianhydride, oxydiphthalic dianhydride, 3,3′,4,4′-benzophenonetetracarboxylic dianhydride, 3,3′,4,4′-diphenyltetracarboxylic dianhydride, 3,3′ ,4,4'-diphenylsulfonetetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride, 2,2'-bis[(dicarboxyphenoxy)phenyl]propane dianhydride etc.

Among the above polycarboxylic acids, polycyclic aromatic polycarboxylic acids are preferred from the viewpoint of dielectric properties, and condensed polycyclic aromatic polycarboxylic acids are particularly preferred. Among the condensed polycyclic aromatic polycarboxylic acids, dimethyl naphthalenedicarboxylate is particularly preferred.
Among the monocyclic aromatic polycarboxylic acids, terephthalic acid, dimethyl terephthalate, isophthalic acid and dimethyl isophthalate are preferred.
In order to reduce crystallinity and ensure stability after dissolution in a solvent, it is preferable to use a plurality of types of polyvalent carboxylic acids.

The content of the aromatic polycarboxylic acid relative to the total polycarboxylic acid is preferably 25 mol% or more, more preferably 40 mol% or more, still more preferably 70 mol% or more, and particularly preferably 90 mol% or more. is. Aromatic polycarboxylic acids may occupy 100 mol %. If the content of the aromatic carboxylic acid is too low, the long-term durability in a moist and hot environment tends to be insufficient, and the low dielectric loss tangent tends to be poor.

The content (molar ratio) of the aromatic polycarboxylic acid relative to the total polycarboxylic acid is obtained from the following formula.
Aromatic polycarboxylic acid content (mol%)
= (aromatic polycarboxylic acids (mol)/polycarboxylic acids (mol)) x 100

The content of structural units derived from aromatic polycarboxylic acids relative to the entire polyester resin (A) is preferably 15 to 70% by weight, more preferably 20 to 65% by weight, and still more preferably 25 to 60% by weight. , particularly preferably 30 to 55% by weight. If the content of the structural unit derived from the aromatic polycarboxylic acid is too small, the initial adhesiveness tends to be insufficient and the low dielectric loss tangent tends to be poor. If the content of structural units derived from aromatic polycarboxylic acids is too high, the initial adhesiveness tends to be insufficient.

Polyvalent carboxylic acids preferably also contain trivalent or higher polyvalent carboxylic acids having 0 or 1 acid anhydride groups. The valence of the carboxy group in such polyvalent carboxylic acids is preferably 3-6 valence, more preferably 3-4 valence. Examples of such polyvalent carboxylic acids include those having 0 or 1 acid anhydride group among the above trifunctional or higher aromatic polyvalent carboxylic acids. Examples include trimellitic anhydride, trimellitic acid, and trimesic acid. Among these, those having one acid anhydride group are preferred, and trimellitic anhydride is particularly preferred.
Examples of trivalent or higher polyvalent carboxylic acids having 0 or 1 acid anhydride groups other than aromatic polyvalent carboxylic acids include hydrogenated trimellitic anhydride.

From the viewpoint of hygroscopicity of the polyester resin (A), sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5(4-sulfophenoxy)isophthalic acid, etc. The content of aromatic dicarboxylic acids having a sulfonic acid group, and aromatic dicarboxylic acid salts having sulfonic acid groups such as metal salts and ammonium salts thereof, relative to the total polycarboxylic acids is 10 mol% or less. It is preferably 5 mol % or less, still more preferably 3 mol % or less, particularly preferably 1 mol % or less, and most preferably 0 mol %.

<Polyhydric alcohols>
Examples of polyhydric alcohols include dimer diols, bisphenol skeleton-containing monomers, aliphatic polyhydric alcohols, alicyclic polyhydric alcohols, and aromatic polyhydric alcohols. One or two or more polyhydric alcohols can be used.

In the present invention, the compound constituting the polyester resin (A) preferably contains dimer diols as polyhydric alcohols.
The dimer diols include, for example, dimer diols which are reductants of dimer acids (mainly those having 36 to 44 carbon atoms) derived from oleic acid, linoleic acid, linolenic acid, erucic acid, etc. and the like. Among them, hydrogenated products are preferable from the viewpoint of suppressing gelation during the production of the polyester-based resin (A).

The dimer diol content relative to the total polyhydric alcohols is preferably 2 to 80 mol%, more preferably 5 to 70 mol%, still more preferably 7 to 65 mol%, particularly preferably 10 to 60 mol%. is. If the content of dimer diols is too low, the hygroscopicity and dielectric properties tend to be poor. If the content of dimer diols is too high, the initial adhesiveness tends to be insufficient.

The content of structural units derived from dimer diols is preferably 5 to 70% by weight, more preferably 10 to 60% by weight, still more preferably 12 to 55% by weight, and particularly preferably 12 to 55% by weight, based on the entire polyester resin (A). is 15 to 50% by weight. If the content of structural units derived from dimer diols is too small, the resulting composition tends to have low hygroscopicity and poor dielectric properties. If the content of structural units derived from dimer diols is too high, initial adhesion tends to be insufficient.

Examples of bisphenol skeleton-containing monomers include bisphenol A, bisphenol B, bisphenol E, bisphenol F, bisphenol AP, bisphenol BP, bisphenol P, bisphenol PH, bisphenol S, bisphenol Z, 4,4′-dihydroxybenzophenone, bisphenol fluorene, Examples include bisphenylphenol fluorenes, hydrogenated products thereof, and glycols such as ethylene oxide adducts and propylene oxide adducts obtained by adding 1 to several moles of ethylene oxide or propylene oxide to the hydroxyl group of bisphenols. . Among them, bisphenolfluorene and bisphenylphenolfluorene having a condensed polycyclic aromatic skeleton are preferred from the viewpoint of low dielectric properties, and ethylene oxide adducts are preferred from the viewpoint of reactivity. In particular, from the viewpoint of heat resistance, low hygroscopicity, and long-term durability in a moist heat environment, adducts of 2 to 3 mol of ethylene oxide are preferred, and bisphenoxyethanol fluorene and bisphenylphenoxyethanol fluorene are most preferred.

Examples of aliphatic polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, and 1,5-pentane. diol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butylpropanediol, dimethylolheptane, 2,2,4 -trimethyl-1,3-pentanediol and the like. Among them, it is preferable to use one having 5 or less carbon atoms from the viewpoint of dielectric properties.

Examples of alicyclic polyhydric alcohols include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, tricyclodecanediol, tricyclodecanedimethanol, and spiroglycol. Among these, polycyclic compounds are preferred from the viewpoint of low dielectric properties, and tricyclodecanedimethanol is more preferred.

Examples of aromatic polyhydric alcohols include para-xylene glycol, meta-xylene glycol, ortho-xylene glycol, 1,4-phenylene glycol, and ethylene oxide adducts of 1,4-phenylene glycol.

Among the above polyhydric alcohols, it is preferable to use polyhydric alcohols having side chains from the viewpoint of solvent solubility and solution stability. Examples of polyhydric alcohols having side chains include bisphenol A, bisphenol B, bisphenol E, bisphenol AP, bisphenol BP, bisphenol P, bisphenol PH, bisphenol S, bisphenol Z, bisphenol fluorene, bisphenylphenol fluorene, and their water Additives, ethylene oxide or propylene oxide adducts obtained by adding 1 to several moles of ethylene oxide or propylene oxide to hydroxyl groups of bisphenols, bisphenol skeleton-containing monomers having side chains such as propylene oxide adducts, 1,2-propylene glycol, 2-methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-ethyl-2-butylpropanediol, dimethylolheptane, 2,2,4-trimethyl- Aliphatic polyhydric alcohols having side chains such as 1,3-pentanediol, and alicyclic polyhydric alcohols having side chains such as tricyclodecanediol, tricyclodecanedimethanol and spiroglycol can be mentioned.

The content of the polyhydric alcohol having a side chain is preferably 10 mol% or more, more preferably 20 mol% or more, still more preferably 30 mol% or more, relative to the total polyhydric alcohols, The upper limit is 95 mol%.
The content of the structural unit derived from a polyhydric alcohol having a side chain is preferably 5% by weight or more, more preferably 10% by weight or more, and still more preferably 15% by weight or more, relative to the entire polyester resin (A). Yes, the upper limit is 50% by weight.
If the content of the polyhydric alcohol having a side chain is too small, the solubility in the solvent and the solution stability of the obtained polyester resin (A) solution tend to decrease.

The content of structural units derived from ether bond-containing glycols other than bisphenol skeleton-containing monomers such as diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. From the viewpoint of low hygroscopicity and long-term durability in a moist and heat environment, it is preferably 20% by weight or less, more preferably 15% by weight or less, and still more preferably 10% by weight with respect to the entire polyester resin (A). Below, it is particularly preferably 8% by weight or less, and most preferably 5% by weight or less.

In the polyester resin (A), in addition to the polyvalent carboxylic acid anhydride to be described later, for the purpose of introducing a branched skeleton as necessary, a tri- or more functional polycarboxylic acid and a tri- or more functional polyhydric alcohol At least one selected from the group consisting of the following may be copolymerized. When a cured product is obtained by reacting with the polyepoxy compound (B) described below, the introduction of a branched skeleton increases the terminal group concentration (reaction point) of the resin, resulting in a cured product with high crosslink density and high strength. Obtainable.

In that case, trifunctional or higher polyvalent carboxylic acids include, for example, trimellitic acid, trimesic acid, ethylene glycol bis(anhydrotrimellitate), glycerol tris(anhydrotrimellitate), trimellitic anhydride, pyromellitic dianhydride, oxydiphthalic dianhydride, 3,3′,4,4′-benzophenonetetracarboxylic dianhydride, 3,3′,4,4′-diphenyltetracarboxylic dianhydride, 3 ,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride, 4,4′-(hexafluoroisopropylidene)diphthalic dianhydride, 2,2′-bis[(dicarboxyphenoxy)phenyl]propane Examples include compounds such as dianhydrides. Examples of tri- or higher functional polyhydric alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.
Tri- or more functional polycarboxylic acids and tri- or more functional polyhydric alcohols may be used alone or in combination of two or more.

When using at least one selected from the group consisting of trifunctional or higher polycarboxylic acids and trifunctional or higher polyhydric alcohols separately from the polycarboxylic anhydride described later, the entire polycarboxylic acid The content of trifunctional or higher polyhydric carboxylic acids, or the content of trifunctional or higher polyhydric alcohols with respect to the total polyhydric alcohols, is preferably 0.1 to 5 mol%, more preferably 0.1 It is in the range of ~3 mol%. If the content of either or both is too high, the adhesive layer formed from the adhesive composition tends to have reduced mechanical properties such as elongation at break, and gelation tends to occur during polymerization. .

<Production of polyester resin (A)>
Polyester-based resin (A) can be produced by a well-known method. For example, a polyhydric carboxylic acid and a polyhydric alcohol may be produced by subjecting them to an esterification reaction in the presence of a catalyst, if necessary, to obtain a polyester resin, and then introducing an acid value. can.

　As a method of introducing an acid value into a polyester resin, for example, a method of introducing a carboxylic acid into the resin by acid addition after an esterification reaction or after reduced pressure polycondensation can be mentioned. When a monocarboxylic acid, dicarboxylic acid, or polyfunctional carboxylic acid compound is used for acid addition, the molecular weight may decrease due to transesterification, so it is preferable to use a compound having at least one carboxylic acid anhydride. Examples of the carboxylic anhydride include succinic anhydride, maleic anhydride, orthophthalic anhydride, 2,5-norbornene dicarboxylic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, and pyromellitic dianhydride. , oxydiphthalic dianhydride, 3,3′,4,4′-benzophenonetetracarboxylic dianhydride, 3,3′,4,4′-diphenyltetracarboxylic dianhydride, 3,3′,4, Compounds such as 4'-diphenylsulfonetetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride, 2,2'-bis[(dicarboxyphenoxy)phenyl]propane dianhydride etc.

When the total structural units derived from polyvalent carboxylic acids constituting the polyester resin are taken as 100 mol %, if 15 mol % or more of acid addition is performed, gelation may occur. Methods of acid addition include a method of direct addition in a bulk state and a method of dissolving and adding a polyester resin. The reaction in the bulk state is fast, but if a large amount is added, gelation may occur and the reaction will be at a high temperature, so it is necessary to take precautions such as blocking oxygen gas to prevent oxidation. On the other hand, addition in a solution state is slow in reaction, but can stably introduce a large amount of carboxyl groups.

When obtaining a polyester resin having a carboxyl group in the side chain, a polycarboxylic acid is added to a hydroxyl group-containing prepolymer obtained by copolymerizing a polycarboxylic acid other than a polycarboxylic anhydride and a polyhydric alcohol. A method of reacting an anhydride is preferable in terms of productivity.

The polyester-based resin (A) can also be obtained by another well-known method, for example, by subjecting polyhydric carboxylic acids and polyhydric alcohols to an esterification reaction, optionally in the presence of a catalyst, to obtain a prepolymer. After obtaining, it can be produced by polycondensing and further depolymerizing.

The temperature in the esterification reaction between polyhydric carboxylic acids and polyhydric alcohols is usually 180-280°C, and the reaction time is usually 60 minutes-8 hours.

The temperature in the polycondensation is usually 220-280°C, and the reaction time is usually 20 minutes-4 hours. Polycondensation is preferably carried out under reduced pressure.

For depolymerization, it is preferable to use trivalent or higher polyvalent carboxylic acids having 0 or 1 acid anhydride groups from the viewpoint of initial adhesiveness. Examples of trivalent or higher polyvalent carboxylic acids having 0 or 1 acid anhydride groups include compounds such as trimellitic acid, trimellitic anhydride, hydrogenated trimellitic anhydride and trimesic acid. Polyvalent carboxylic acids having a valence of 3 or more and having one acid anhydride group are preferred from the viewpoint of suppressing a decrease in molecular weight, and examples thereof include trimellitic anhydride and hydrogenated trimellitic anhydride. Trimellitic anhydride is particularly preferred from the viewpoint of low dielectric loss tangent.
The temperature in the depolymerization is usually 200-260° C., and the reaction time is usually 10 minutes-3 hours.

When the structural units derived from all polyvalent carboxylic acids constituting the polyester-based resin are 100 mol%, more than 20 mol% of trivalent or higher polyvalent carboxylic acids having 0 or 1 acid anhydride groups are used. Depolymerization can significantly reduce the molecular weight of the resin. Therefore, when the structural units derived from all polyvalent carboxylic acids constituting the polyester resin are 100 mol%, 20 mol% or less of trivalent or higher polyvalent carboxylic acids having 0 or 1 acid anhydride groups are used. Depolymerization is preferably carried out, more preferably 1 to 15 mol %, still more preferably 2 to 10 mol %, particularly preferably 3 to 9 mol %.

<Ester bond concentration of polyester resin (A)>
The ester bond concentration of the polyester resin (A) is preferably 10 mmol/g or less, more preferably 1 to 9 mmol/g, still more preferably 2 to 8.5 mmol/g, particularly preferably 2.5 ~8 mmol/g, particularly preferably 3 to 7.5 mmol/g.
If the ester bond concentration is too high, low hygroscopicity and long-term durability in a moist and heat environment will be insufficient. If the ester bond concentration is too low, the initial adhesion will be insufficient.

The definition and measuring method of the ester bond concentration are as follows.
The ester bond concentration (mmol/g) is the number of moles of ester bonds in 1 g of the polyester-based resin, and is obtained, for example, by a calculated value from the charged amount. This calculation method is a value obtained by dividing the number of moles of the smaller of the charged amounts of the polyhydric carboxylic acid and the polyhydric alcohol by the total weight of the resin, and an example of the calculation formula is shown below.
When the polyhydric carboxylic acid and the polyhydric alcohol are charged in the same molar amount, either of the following formulas may be used.
If a monomer having both a carboxy group and a hydroxyl group is used, or if a polyester is produced from caprolactone or the like, the calculation method will be changed as appropriate.

(When polyhydric carboxylic acids are less than polyhydric alcohols)
Ester bond concentration (mmol/g)
＝[(A1/a1×m1+A2/a2×m2+A3/a3×m3……)/Z]×1000
A: Charge amount (g) of polyvalent carboxylic acid
a: molecular weight of polyvalent carboxylic acid m: number of carboxylic acid groups per molecule of polyvalent carboxylic acid Z: finished weight (g)

(When polyhydric alcohols are less than polyhydric carboxylic acids)
Ester bond concentration (mmol/g)
=[(B1/b1×n1+B2/b2×n2+B3/b3×n3……)/Z]×1000
B: Charged amount of polyhydric alcohol (g)
b: molecular weight of polyhydric alcohol n: number of hydroxyl groups per molecule of polyhydric alcohol Z: finished weight (g)

The above ester bond concentration can also be measured by a known method using NMR or the like.

Concentrations of other polar groups other than ester bonds and reactive functional groups are preferably low from the viewpoint of low hygroscopicity and long-term durability in wet and heat environments.
Other polar groups include, for example, amide groups, imide groups, urethane groups, urea groups, ether groups, carbonate groups and the like.

The total concentration of amide groups, imide groups, urethane groups, and urea groups is preferably 3 millimoles/g or less, more preferably 2 millimoles/g or less, still more preferably 1 millimoles/g or less, and particularly preferably is less than or equal to 0.5 mmol/g, most preferably less than or equal to 0.2 mmol/g.
Ether groups include, for example, alkyl ether groups and phenyl ether groups. In terms of low hygroscopicity and long-term durability in a moist and hot environment, it is particularly preferred to lower the concentration of alkyl ether groups.
The alkyl ether group concentration is preferably 3 mmol/g or less, more preferably 2 mmol/g or less, still more preferably 1.5 mmol/g or less, particularly preferably 1 mmol/g or less, and most preferably is less than or equal to 0.5 mmol/g.
The phenyl ether group concentration is preferably 5 mmol/g or less, more preferably 4 mmol/g or less, still more preferably 3 mmol/g or less, and particularly preferably 2.5 mmol/g or less.
The carbonate group concentration is preferably 3 mmol/g or less, more preferably 2 mmol/g or less, still more preferably 1 mmol/g or less, particularly preferably 0.5 mmol/g or less, and most preferably 0.2 mmol/g or less.

<Dielectric properties of polyester resin (A)>
(Dielectric loss tangent (Df))
The dielectric loss tangent (Df) at a frequency of 10 GHz in an environment of a temperature of 23 ° C. and a relative humidity of 50% RH of the polyester resin (A) is preferably 0.005 or less, more preferably 0.0045 or less, and still more preferably It is 0.004 or less, more preferably 0.0035 or less, and particularly preferably 0.003 or less. If the dielectric loss tangent is too high, the resulting laminate will have a large transmission loss.

(relative permittivity (Dk))
The relative dielectric constant (Dk) of the polyester resin (A) at a temperature of 23° C. and a relative humidity of 50% RH at a frequency of 10 GHz is preferably 2.9 or less, more preferably 2.8 or less, and still more preferably 2. 0.7 or less, particularly preferably 2.6 or less. If the dielectric constant is too high, the resulting laminate tends to have a low transmission speed or a large transmission loss.

　The dielectric constant and dielectric loss tangent of the polyester resin (A) can be obtained by the cavity resonator perturbation method using a network analyzer. If it is difficult to prepare a measurement sample by itself due to the strong adhesiveness of the polyester resin (A), the dielectric properties of the polyester resin (A) alone can be estimated by measuring the sample sandwiched between films and subtracting the film amount. can also be calculated.

<Acid value of polyester resin (A)>
The acid value of the polyester resin (A) is preferably 3 mgKOH/g or more, more preferably 4 mgKOH/g or more, still more preferably 5 mgKOH/g or more, particularly preferably 6 mgKOH/g or more, particularly preferably 7 mgKOH/g or more. is. On the other hand, the acid value of the polyester resin (A) is preferably 60 mgKOH/g or less, more preferably 40 mgKOH/g or less, still more preferably 30 mgKOH/g or less, and particularly preferably 20 mgKOH/g or less.
If the acid value of the polyester-based resin (A) is too low, when the polyepoxy-based compound (B) is included in the adhesive composition, the cross-linking points with the polyepoxy-based compound (B) are insufficient, resulting in a low degree of cross-linking. As a result, the heat resistance becomes insufficient. If the acid value of the polyester-based resin (A) is too high, the hygroscopicity and long-term durability in a moist and heat environment are reduced, and a large amount of the polyepoxy-based compound (B) is required during curing. It tends to be inferior in dielectric properties, which has become more common.

The definition and measuring method of the acid value are as follows.
The acid value (mgKOH/g) can be obtained by dissolving 1 g of a polyester resin in 30 g of a mixed solvent of toluene/methanol (for example, toluene/methanol=7/3 by volume) and performing neutralization titration based on JIS K0070. can.
In the present invention, the acid value of the polyester resin (A) is due to the content of carboxy groups in the resin.

<Glass transition temperature (Tg) of polyester resin (A)>
The glass transition temperature (Tg) of the polyester resin (A) is preferably −5° C. or higher, more preferably 0° C. or higher, still more preferably 3° C. or higher, particularly preferably 5° C. or higher, particularly preferably 7° C. above, and most preferably above 10°C. On the other hand, the glass transition temperature (Tg) of the polyester resin (A) is preferably 100° C. or lower, more preferably 80° C. or lower, still more preferably 60° C. or lower, particularly preferably 40° C. or lower, particularly preferably 30° C. or lower. is.
If the glass transition temperature (Tg) of the polyester-based resin (A) is too low, initial adhesiveness and tack-free properties will be insufficient. If the glass transition temperature (Tg) of the polyester-based resin (A) is too high, the initial adhesiveness and flexibility tend to be insufficient.

The method for measuring the glass transition temperature (Tg) is as follows.
The glass transition temperature (Tg) can be obtained by measuring with a differential scanning calorimeter. The measurement conditions are a measurement temperature range of -70 to 140°C and a temperature increase rate of 10°C/min.

<Peak Top Molecular Weight (Mp) and Weight Average Molecular Weight (Mw) of Polyester Resin (A)>
The peak top molecular weight (Mp) of the polyester resin (A) is preferably 5,000 to 150,000, more preferably 10,000 to 100,000, even more preferably 15,000 to 70,000, and particularly preferably 25,000 to 40,000.
If the peak top molecular weight (Mp) is too low, low hygroscopicity, tack-free property, and long-term durability in a moist heat environment will be insufficient, and flexible laminates such as flexible copper-clad laminates and flexible printed circuit boards will be produced. There is a tendency that problems such as the polyester-based resin of the adhesive layer flowing and oozing out during press processing when bonding are likely to occur. If the peak top molecular weight (Mp) is too high, the initial adhesion may be insufficient, or the viscosity of the solution at the time of coating may be too high, making it difficult to obtain a uniform coating film.

The weight average molecular weight (Mw) of the polyester resin (A) is preferably 5,000 to 300,000, more preferably 10,000 to 200,000, still more preferably 20,000 to 150,000, and particularly preferably 25,000 to 100,000.
If the weight average molecular weight (Mw) is too low, low hygroscopicity, tack-free property, and long-term durability in a moist heat environment will be insufficient, and flexible laminates such as flexible copper-clad laminates and flexible printed circuit boards will be produced. There is a tendency that problems such as the polyester-based resin of the adhesive layer flowing and oozing out during press processing when bonding are likely to occur. If the weight-average molecular weight (Mw) is too high, the initial adhesion may be insufficient, or the solution viscosity at the time of coating may be too high, making it difficult to obtain a uniform coating film.

Methods for measuring peak top molecular weight (Mp) and weight average molecular weight (Mw) are as follows.
The peak top molecular weight (Mp) and weight average molecular weight (Mw) were measured by high-performance liquid chromatography (manufactured by Tosoh Corporation, "HLC-8320GPC") on a column (TSKgel SuperMultipore HZ-M (exclusion limit molecular weight: 2 × 106, number of theoretical plates). : 16,000 plates/line, filler material: styrene-divinylbenzene copolymer, filler particle diameter: 4 μm))))), and can be obtained by standard polystyrene molecular weight conversion.

<Water absorption rate (% by weight) of polyester resin (A)>
The water absorption of the polyester resin (A) is preferably 2% by weight or less, more preferably 1% by weight or less, still more preferably 0.8% by weight or less, and particularly preferably 0.6% by weight or less.
If the water absorption is too high, the wet heat durability and insulation reliability tend to deteriorate, and the dielectric properties tend to deteriorate. Inferior in dielectric properties means that the values of relative permittivity and dielectric loss tangent do not decrease or increase.

The method for measuring water absorption is as follows.
The polyester resin solution (before blending the polyepoxy compound (B) and the filler (C)) was applied onto the release film with an applicator and dried at 120°C for 10 minutes, and the dry film thickness of the polyester resin layer was 65 µm. Make a sheet. This sheet is cut into a size of 7.5 cm×11 cm, the polyester-based resin layer surface of the sheet is laminated on a glass plate, and then the release film is peeled off. By repeating this operation six times, a test plate having a polyester-based resin layer with a thickness of 390 μm on a glass plate is obtained.
After immersing the thus-obtained test plate in purified water at 23°C for 24 hours, it is taken out, the water on the surface is wiped off, and dried at 70°C for 2 hours. The weight required in each of these steps is measured, and the water absorption (% by weight) is calculated from the change in weight according to the following formula.
Water absorption (% by weight) = (cd) x 100/(ba)
a: Weight of the glass plate alone b: Weight of the initial test plate c: Weight of the test plate immediately after removing from the purified water and wiping off moisture d: Weight of the test plate after drying at 70 ° C. for 2 hours

<Content of polyester resin (A)>
The adhesive composition of the present invention may contain only the polyester resin (A) as the polyester resin, or may contain a polyester resin other than the polyester resin (A). The content of the polyester resin (A) in the adhesive composition of the invention is preferably more than 50% by weight, more preferably 70% by weight or more, and still more preferably 85% by weight or more of the total polyester resin. Yes, and may be 100% by weight. If the content of the polyester-based resin (A) is too small, the low hygroscopicity and the long-term durability in a moist and hot environment tend to be insufficient, and the low dielectric loss tangent tends to be poor.

[Polyepoxy compound (B)]
The adhesive composition of the present invention contains a polyepoxy compound (B). Since the adhesive composition of the present invention contains the polyepoxy compound (B), the epoxy groups in the polyepoxy compound (B) and the carboxy groups in the polyester resin (A) react to cure. As a result, it is possible to obtain an adhesive layer that is excellent not only in adhesive strength but also in solder heat resistance.

The equivalent weight of the epoxy group of the polyepoxy compound (B) in the adhesive composition to the carboxy group of the polyester resin (A) in the adhesive composition is preferably less than 2, more preferably 1.9 or less, and further It is preferably 1.7 or less, particularly preferably 1.5 or less. On the other hand, the equivalent weight of the epoxy group of the polyepoxy compound (B) in the adhesive composition to the carboxy group of the polyester resin (A) in the adhesive composition is preferably 0.1 or more, more preferably 0.1. It is 3 or more, more preferably 0.5 or more, and most preferably 0.8 or more.
If the corresponding amount is too large, the initial adhesiveness and low hygroscopicity tend to become insufficient, the dielectric properties deteriorate, and the solder heat resistance tends to deteriorate. If the corresponding amount is too small, there is a tendency that the long-term durability and solder heat resistance in a moist and hot environment become insufficient.

The equivalent weight of the epoxy group to the carboxy group (COOH) is obtained from the acid value of the polyester resin (A) and the epoxy equivalent weight (g/eq) of the blended polyepoxy compound (B) by the following formula.
Equivalent weight of epoxy group to COOH = (e÷WPE)/(AV÷56.1÷1000×P)
e: weight (g) of the polyepoxy compound (B) used in the formulation
WPE: epoxy equivalent (g/eq) of polyepoxy compound (B)
AV: Acid value of polyester resin (A) (mgKOH/g)
p: Weight (g) of the polyester resin (A) used in the formulation

The epoxy equivalent WPE of the polyepoxy compound (B) is preferably 500 g/eq or less, more preferably 350 g/eq or less, still more preferably 250 g/eq or less, and particularly preferably 200 g/eq or less. If the epoxy equivalent of the polyepoxy compound (B) is too large, the crosslink density after curing will be low, resulting in poor solder heat resistance, or it will be necessary to add a large amount of the polyepoxy compound (B) to increase the crosslink density. Therefore, it tends to be inferior in dielectric properties. The epoxy equivalent WPE of the polyepoxy compound (B) is usually 50 g/eq or more.
In the present invention, "epoxy equivalent (WPE)" is defined as "weight of epoxy resin containing one equivalent of epoxy group" and can be measured according to JIS K7236.

Examples of the polyepoxy compound (B) include glycidylamine types such as tetraglycidyldiaminodiphenylmethane, triglycidyl para-aminophenol, tetraglycidylbisaminomethylcyclohexane, and N,N,N',N'-tetraglycidyl-m-xylenediamine. nitrogen atom-containing polyepoxy compounds. In addition, bifunctional glycidyl ether types such as bisphenol A diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether; polyfunctional glycidyl ether types such as phenol novolac glycidyl ether and cresol novolac glycidyl ether; hexahydrophthalic acid Glycidyl ester types such as glycidyl ester and dimer acid glycidyl ester; alicyclic or aliphatic epoxides such as triglycidyl isocyanurate, 3,4-epoxycyclohexylmethyl carboxylate, epoxidized polybutadiene, and epoxidized soybean oil; Polyepoxy compound (B) can be used alone or in combination of two or more.

When the adhesive composition of the present invention contains a nitrogen atom-containing polyepoxy compound (nitrogen atom-containing polyepoxy compound) as the polyepoxy compound (B), the adhesive composition can be formed by heating at a relatively low temperature. There is a tendency that the coating film of the object can be B-staged (semi-cured state), and the fluidity of the B-stage film can be suppressed to improve the workability in the bonding operation. Moreover, the effect of suppressing the foaming of the B-stage film can be expected, which is preferable.

[Filler (C)]
The adhesive composition of the present invention contains filler (C). By containing the filler (C), it is possible to obtain an adhesive that is excellent not only in adhesive strength but also in solder heat resistance. In addition, various functionalities such as flame retardancy can be imparted.

The filler is not particularly limited, but may be spherical, powdery, fibrous, needle-like, scale-like, or the like.

Examples of fillers include polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer (ETFE), polychlorotri Fluoropolymer powder such as fluoroethylene (PCTFE), fluororubber (FKM), polyethylene powder, polyacrylate powder, epoxy resin powder, polyamide powder, polyurethane powder, polysiloxane powder, silicone, acrylic, styrene Polymer filler such as butadiene rubber, multi-layered core-shell using butadiene rubber;
(Poly)phosphates such as melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, amide ammonium phosphate, amide ammonium polyphosphate, carbamate phosphate, and carbamate polyphosphate phosphines such as compounds, organophosphate compounds, phosphazene compounds, phosphonic acid compounds, aluminum diethylphosphinate, aluminum methylethylphosphinate, aluminum diphenylphosphinate, aluminum ethylbutylphosphinate, aluminum methylbutylphosphinate, and aluminum polyethylenephosphinate Phosphorus-based flame retardant fillers such as acid compounds, phosphine oxide compounds, phosphorane compounds, and phosphoramide compounds;
Nitrogen-based flame retardant fillers such as benzoguanamine, melamine, melam, melem, melon, melamine cyanurate, cyanuric acid compounds, isocyanuric acid compounds, triazole compounds, tetrazole compounds, diazo compounds, and urea;
Silica, silicon nitride, boron nitride, aluminum nitride, calcium hydrogen phosphate, calcium phosphate, glass flakes, hydrated glass, calcium titanate, sepiolite, magnesium sulfate, aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, barium hydroxide, Calcium hydroxide, titanium oxide, tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, antimony oxide, nickel oxide, zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, zinc borate, aluminum borate inorganic fillers such as;
Kaolinite group clay minerals (halloysite, kaolinite, endellite, dickite, nacrite, etc.), antigorite group clay minerals (antigorite, chrysotile, etc.), smectite group clay minerals (montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, stevensite, etc.), vermiculite group clay minerals (vermiculite, etc.), mica or mica group clay minerals (muscovite, phlogopite, etc. mica, margarite, tetrasilic mica, teniolite, etc.), talc, clay, Clay minerals such as hydrotalcite, wollastonite, xonotlite, synthetic mica;
etc.
One or two or more fillers (C) can be used.

Among these fillers, fluoropolymer powder (C1) and/or clay mineral (C2) are preferable from the viewpoint of further reducing the dielectric constant and dielectric loss tangent and further improving the effects of the present invention. By containing the fluoropolymer powder (C1) and/or the clay mineral (C2), it is possible to obtain an adhesive having not only initial adhesive strength, but also low dielectric properties and high adhesive strength even after a wet heat durability test. can. From the viewpoint of dispersibility in the polyester-based resin (A), clay minerals are more preferred, and mica is particularly preferred.

Examples of the fluoropolymer powder (C1) include polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer ( ETFE), polychlorotrifluoroethylene (PCTFE), fluororubber (FKM), and the like. These may be used alone or in combination of two or more.
The fluorine-based polymer powder (C1) is preferable from the viewpoint of further reducing the dielectric constant and dielectric loss tangent and further improving the effects of the present invention. It is particularly preferable from the viewpoint of compatibility and dispersibility with (A). By blending the fluorine-based polymer powder, it becomes possible to obtain a cured product having not only dielectric properties but also an excellent balance among adhesiveness, flexibility, electrical insulation and heat resistance.

Examples of the clay mineral (C2) include kaolinite group clay minerals (halloysite, kaolinite, endellite, dickite, nacrite, etc.), antigorite group clay minerals (antigorite, chrysotile, etc.), smectite group clay minerals ( montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, stevensite, etc.), vermiculite group clay minerals (vermiculite, etc.), mica or mica group clay minerals (muscovite, phlogopite, mica, margarite, tetrasilic mica, teniolite, etc.), talc, clay, hydrotalcite, wollastonite, xonotlite, synthetic mica, and the like. These may be used alone or in combination of two or more.
Among these clay minerals (C2), mica group clay minerals and synthetic mica are preferred, and synthetic mica is more preferred, in terms of dispersibility in the polyester resin (A).

The average particle size of these fillers (C) is preferably 0.1 μm to 25 μm. When a filler having an average particle diameter close to 0.1 μm is used, the modification effect of the filler is likely to be obtained, and the dispersibility and the stability of the dispersion liquid are likely to be improved. When a filler having an average particle size close to 25 μm is used, the mechanical properties of the cured film are likely to be improved.

[Formulation of Adhesive Composition]
The adhesive composition of the present invention contains a polyester-based resin (A), a polyepoxy-based compound (B) and a filler (C), and has low transmission properties, low moisture absorption, tack-free properties, initial adhesiveness, and a moist heat environment. It has an effect of being excellent in long-term durability under the environment.

The content of the polyepoxy compound (B) in the adhesive composition of the present invention is such that the epoxy groups of the polyepoxy compound (B) to the carboxy groups of the polyester resin (A) are in the aforementioned suitable equivalent ratio. If it is More specifically, the content of the polyepoxy compound (B) is preferably 0.5 to 30 parts by weight, more preferably 1 to 20 parts by weight, with respect to 100 parts by weight of the polyester resin (A). More preferably 1.5 to 15 parts by weight, particularly preferably 1.8 to 5 parts by weight. If the content of the polyepoxy-based compound (B) is too small, the heat resistance and long-term durability in a moist and hot environment tend to be insufficient. If the content of the polyepoxy-based compound (B) is too high, the initial adhesiveness and low hygroscopicity tend to be insufficient, and the dielectric properties tend to be poor.

The content of the filler (C) in the adhesive composition of the present invention is preferably 1 to 100 parts by weight, more preferably 5 to 90 parts by weight, and still more preferably 100 parts by weight of the polyester resin (A). 10 to 80 parts by weight, particularly preferably 15 to 70 parts by weight, particularly preferably 20 to 60 parts by weight. When the content of the filler (C) is within the above range, it is possible to reduce the dielectric loss tangent and improve the long-term durability in a wet and hot environment without impairing the adhesiveness, which is preferable. If the content of the filler (C) is too high, the adhesiveness tends to decrease.

[catalyst]
The adhesive composition of the present invention containing the polyepoxy compound (B) may contain a catalyst for curing.

Examples of catalysts include 2-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, and the like. Imidazole compounds; triethylamine, triethylenediamine, N'-methyl-N-(2-dimethylaminoethyl)piperazine, 1,8-diazabicyclo(5,4,0)-undecene-7, 1,5-diazabicyclo(4, 3,0)-nonene-5,6-dibutylamino-1,8-diazabicyclo(5,4,0)-undecene-7 and other tertiary amines; compounds converted into amine salts with quaternized tetraphenylborate salts; cationic catalysts such as triallylsulfonium hexafluoroantimonate and diallyiodonium hexafluoroantimonate; and triphenylphosphine. Among these, 1,8-diazabicyclo(5,4,0)-undecene-7 and 1,5-diazabicyclo(4,3,0)-nonene-5,6-dibutylamino-1,8-diazabicyclo(5 ,4,0)-undecene-7 and other tertiary amines; and compounds obtained by converting these tertiary amines into amine salts with phenol, octylic acid, quaternary tetraphenylborate salts, etc., are thermosetting and heat-resistant. It is preferable in terms of properties, adhesion to metals, and storage stability after compounding. These catalysts can be used alone or in combination of two or more.

When the adhesive composition of the present invention contains a catalyst, the content thereof is preferably 0.01 to 1 part by weight per 100 parts by weight of the polyester resin (A). Within this range, the catalytic effect on the reaction between the polyester-based resin (A) and the polyepoxy-based compound (B) is further increased, and strong adhesion performance can be obtained.

[solvent]
A solvent may be added to the adhesive composition of the present invention in order to appropriately adjust the viscosity of the adhesive composition and to facilitate handling when forming a coating film. The solvent is used to ensure handleability and workability in molding the adhesive composition, and the amount used is not particularly limited.

Examples of solvents include ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone and cyclohexanone; esters such as ethyl acetate; ethers such as ethylene glycol monomethyl ether; amides such as dimethylacetamide; alcohols such as methanol and ethanol; alkanes such as hexane and cyclohexane; aromatics such as toluene and xylene, and the like. Only one kind of solvent may be used, or two or more kinds may be mixed and used in any combination and ratio.

[Other ingredients]
The adhesive composition of the present invention may contain components other than those listed above for the purpose of further improving its functionality. Other components include, for example, coupling agents such as silane coupling agents, UV inhibitors, antioxidants, plasticizers, fluxes, flame retardants, colorants, dispersants, emulsifiers, elasticity reducing agents, diluents, Antifoaming agents, ion trapping agents, leveling agents, catalysts and the like are included.

When the adhesive composition of the present invention contains these other components, the content of the other components is preferably 40% by weight or less, more preferably 0.05 to 30% by weight, and still more preferably 0% by weight. .1 to 20% by weight, particularly preferably 0.2 to 10% by weight.

[Dielectric Properties of Adhesive Composition]
<Dielectric loss tangent (Df)>
The cured product of the adhesive composition of the present invention has a dielectric loss tangent (Df) of 0.005 or less, preferably 0.004 or less, and more preferably at a frequency of 10 GHz under an environment of a temperature of 23° C. and a relative humidity of 50% RH. is 0.0038 or less, more preferably 0.0036 or less, still more preferably 0.0034 or less, particularly preferably 0.0032 or less, particularly preferably 0.0030 or less, and most preferably 0.0028 or less. If the dielectric loss tangent is too high, the transmission loss will increase when used in a laminate.

<Dielectric constant (Dk)>
The cured product of the adhesive composition of the present invention has a dielectric constant (Dk) of preferably 3.0 or less, more preferably 2.9 or less, at a frequency of 10 GHz under an environment of a temperature of 23° C. and a relative humidity of 50% RH. It is more preferably 2.8 or less, particularly preferably 2.7 or less. If the dielectric constant is too high, the transmission speed tends to be low and the transmission loss tends to increase when used in a laminate.

The method for measuring the dielectric loss tangent and the dielectric constant of the cured product of the adhesive composition of the present invention can be obtained by the cavity resonator perturbation method using a network analyzer. If the adhesion of the adhesive composition is too strong to prepare a measurement sample by itself, it is also possible to measure with the film sandwiched and subtract the film component to calculate the dielectric properties of the adhesive composition alone. can.

Examples of methods for obtaining an adhesive composition having excellent dielectric properties such that the dielectric loss tangent and the dielectric constant are equal to or less than the above upper limits include the following methods.
(1) A polyester-based resin (A) having a low dielectric loss tangent and a low dielectric constant is used.
(2) Designing a composition with few polar groups that deteriorate the dielectric properties.
(3) A low dielectric filler is also used as the filler (C).

[Adhesion layer]
The adhesive layer obtained by curing the adhesive composition of the present invention exhibits the effects of being excellent in initial adhesiveness, low hygroscopicity, and long-term durability under moist and heat environments.

"Curing" in the present invention means intentionally curing the adhesive composition with heat and/or light, etc., and the degree of curing can be controlled according to desired physical properties and applications. The degree of curing can be confirmed by the gel fraction of the adhesive, which is preferably 50% or more, more preferably 60% or more, particularly preferably 70% or more, and still more preferably 75% or more. If the gel fraction is too low, the heat resistance and long-term durability in a moist and hot environment tend to be insufficient.
The above-mentioned gel fraction means the weight percentage of the undissolved cured product component relative to the weight of the cured product obtained by immersing the cured product of the adhesive composition in methyl ethyl ketone at 23° C. for 24 hours before immersion.

The curing method of the adhesive composition when curing or semi-curing the adhesive composition of the present invention varies depending on the ingredients and amounts in the adhesive composition, but is usually 80 to 200° C. for 10 minutes to 10 minutes. heating conditions of hours.

[Use]
Since the adhesive composition of the present invention is excellent in initial adhesiveness, low moisture absorption, and long-term durability in a moist and heat environment, it is effective for bonding substrates made of various materials such as resins and metals. It is suitable as an adhesive for producing a laminated plate of a layer and a plastic layer, for example, an adhesive used for bonding electronic material members to be described later.

[Laminate]
The laminate of the present invention is a laminate having an adhesive layer on at least one surface of a substrate or a conductor layer, wherein the adhesive layer comprises a polyester resin (A), a polyepoxy compound (B), and a filler. It is a cured product of an adhesive composition containing (C), and the adhesive layer (hereinafter sometimes referred to as the "adhesive layer of the present invention") exhibits a specific dielectric loss tangent (Df).

[Adhesive composition]
As the adhesive composition constituting the adhesive layer of the laminate of the present invention, the above-described adhesive composition of the present invention can be used, and the curing method for forming the adhesive layer is also as described above.

[Dielectric properties of adhesive layer]
<Dielectric loss tangent (Df)>
The dielectric loss tangent (Df) of the adhesive layer of the present invention at a frequency of 10 GHz under an environment of a temperature of 23° C. and a relative humidity of 50% RH is 0.005 or less, preferably 0.004 or less, more preferably 0.0038 or less. , more preferably 0.0036 or less, still more preferably 0.0034 or less, particularly preferably 0.0032 or less, particularly preferably 0.0030 or less, and most preferably 0.0028 or less. If the dielectric loss tangent is too high, the transmission loss of the laminate will increase.

<Dielectric constant (Dk)>
The dielectric constant (Dk) of the adhesive layer of the present invention at a frequency of 10 GHz under an environment of a temperature of 23° C. and a relative humidity of 50% RH is preferably 3.0 or less, more preferably 2.9 or less, still more preferably 2.9. 8 or less, particularly preferably 2.7 or less. If the dielectric constant is too high, the transmission speed of the laminate tends to be low and the transmission loss tends to increase.

The dielectric loss tangent and dielectric constant of the adhesive layer of the present invention can be measured by the same method as the method for measuring the cured product of the adhesive composition of the present invention described above.

With respect to the method for obtaining an adhesive layer having excellent dielectric properties in which the dielectric loss tangent and the dielectric constant are equal to or less than the above upper limits, the adhesive composition of the present invention having excellent dielectric properties can be obtained. The method for forming the adhesive layer of the present invention is as described above.
(1) A polyester-based resin (A) having a low dielectric loss tangent and a low dielectric constant is used in the adhesive composition.
(2) The adhesive composition is designed to contain few polar groups that deteriorate the dielectric properties.
(3) A low dielectric filler is also used as the filler (C).

[Thickness of adhesive layer]
The thickness of the adhesive layer of the present invention is usually 1 to 200 μm, although it varies depending on the application of the laminate.

[Method for Forming Adhesive Layer]
The adhesive layer of the present invention can be produced by applying the adhesive composition of the present invention to a substrate or conductor layer, which will be described later. More specifically, after the resin composition is applied to the substrate or conductor layer, it is semi-cured (hereinafter also referred to as B stage) under certain conditions (temperature: 80 to 180 ° C., time: 2 to 30 minutes). to obtain an adhesive layer. The thickness of the coating film may be about 1 to 200 μm, depending on the application. The coating method is not particularly limited, and examples thereof include methods such as a comma coater, die coater, gravure coater, and roll coater. In addition, the adhesive layer in the completely cured state (C stage) is obtained by laminating the adhesive layer in the B stage with another base material or conductor layer using a laminator or a press, and then applying a certain curing condition (temperature: 80 to 200 ° C., pressure: 0 to 3 MPa, time: 10 to 600 minutes).
In the laminate of the present invention, the adhesive layer of the present invention may be formed only on one surface of the substrate or conductor layer, or may be formed on both surfaces.

[Base material]
The base material of the laminate of the present invention is not particularly limited.
Specific examples of the substrate include polyimide film, polyetheretherketone film, polyphenylene sulfide film, aramid film, polyethylene naphthalate film, liquid crystal polymer film, polyethylene terephthalate film, polyethylene film, polypropylene film, and silicone release treated paper. , polyolefin resin-coated paper, polymethylpentene film, and fluororesin film. These are preferable when the laminate of the present invention is used as a flexible laminate, which will be described later.
Only one type of these base materials may be used, or two or more types may be used. For example, two or more of the above substrates may be laminated and used. Moreover, in this case, the adhesive layer of the present invention may be formed between the substrates.

Among the above substrates, polyimide film, polyether ether ketone film, polyphenylene sulfide film, aramid film, polyethylene naphthalate film, liquid crystal polymer film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, and fluorine resin Films are preferred, and among these, polyimide films, polyethylene naphthalate films, and liquid crystal polymer films are more preferred, and polyimide films and liquid crystal polymer films are even more preferred, from the viewpoint of adhesiveness and electrical properties.

There are no particular restrictions on the thickness of the base material, and it is appropriately designed according to the application of the laminate and the material of the base material used. From the viewpoint of obtaining the desired strength, it is preferably in the range of 1 to 500 μm, particularly 3 to 100 μm, especially 5 to 50 μm.

[Conductor layer]
Examples of conductors forming the conductor layer include foils made of general copper or copper alloys, stainless steel or alloys thereof, nickel or nickel alloys (including 42 alloys), aluminum or aluminum alloys. Copper foils such as rolled copper foils and electrolytic copper foils are often used as general circuit board materials, and they can also be preferably used in the present invention. A rust preventive layer, a heat resistant layer, or an adhesive layer may be applied to the surface of these metal foils. Moreover, the thickness of the metal foil is not particularly limited, and may be any thickness that can exhibit sufficient functions according to the application.
The conductor layer may be formed in a pattern as a circuit, or may be formed in a plane.

The thickness of the conductor layer is usually about 1 to 100 μm.

[Other layers]
The laminate of the present invention may have other layers in addition to the adhesive layer of the present invention and the substrate or conductor layer.
The other layer is preferably a base material or a conductor layer, particularly when the laminate of the present invention is applied to a circuit board material.

Moreover, the laminate of the present invention may have a release layer so as to be in contact with the adhesive layer of the present invention.
Examples of the release film that forms the release layer include polyolefin films such as polyethylene and polypropylene; polyester films such as polyethylene terephthalate and polyethylene naphthalate; polyimide films; can.
The thickness of the release film is preferably 1 to 300 μm, more preferably 5 to 200 μm, still more preferably 10 to 150 μm, particularly preferably 20 to 120 μm.
The release film may be subjected to matte treatment, corona treatment, or antistatic treatment on the surface in contact with the adhesive layer of the present invention.

In addition, the laminate of the present invention may have one or more of an adhesive layer, an insulating layer, and a conductor layer other than the above.

[Use]
Applications of the laminate of the present invention include, for example, electronic material members such as flexible copper-clad laminates, coverlays, bonding sheets, and resin-coated copper foils.
Examples of products manufactured by laminating electronic material members include flexible laminates such as flexible printed circuit boards, multilayer printed wiring boards, laminates for electrical and electronic circuits such as capacitors, underfill materials, and 3D-LSI interconnects. A chip fill, an insulating sheet, a heat dissipation substrate, and the like can be mentioned. In addition, the laminate of the present invention can be used as a material for circuit boards, but is not limited to these.
A flexible laminate is, for example, a laminate obtained by sequentially laminating "flexible flexible substrate/adhesive layer/conductive metal layer made of copper, aluminum, alloys thereof, etc.", and constitutes the adhesive layer. The adhesive of the present invention can be used as an adhesive. In addition to the various layers described above, the flexible laminate may further include other insulating layers, other adhesive layers, and other conductive metal layers.

One aspect of the laminate of the present invention is a circuit board material.
Further, another aspect of the laminate of the present invention includes a flexible copper-clad laminate, a coverlay film, a bonding sheet, a resin-coated copper foil, and the like.

[Circuit board material]
A circuit board material as one aspect of the laminate of the present invention can be produced, for example, by the following method.
After forming the adhesive layer of the present invention on a base material or conductor layer, further laminating a conductor or base material thereon, a circuit is formed using a photoresist or the like, and the necessary number of such layers are stacked.
The lamination of the substrate and the conductor layer may be performed by directly laminating the conductive metal foils or by bonding the conductive metal foils with the adhesive composition of the present invention. Alternatively, a method of forming a conductive metal layer by plating or sputtering may be used, or a combination of these methods may be used.

Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the following, "parts" and "%" mean weight basis.

Proportion of aromatic polycarboxylic acids to the total polycarboxylic acids (mol%) (referred to as "aromatic acid content" in Table 1-B), ester bond concentration (mmol/g), water absorption (%) , glass transition temperature (Tg) (° C.), acid value (mgKOH/g), peak top molecular weight (Mp), weight average molecular weight (Mw), dielectric properties, equivalent weight of epoxy group to COOH (epoxy/COOH), Measurements were performed as described herein.

[Manufacturing of polyester resin]
The composition (molar ratio) shown in Table 1-A below is the finished composition ratio (resin composition ratio), and is the relative ratio (molar ratio) of the amount of each constituent monomer of the obtained polyester resin.

<Production Example 1: Production of polyester resin (A-1)>
A thermometer, a stirrer, a rectifying column, and a reactor equipped with a nitrogen inlet tube were charged with 53.8 parts (0.3238 mol) of terephthalic acid (TPA) and 212.7 parts of isophthalic acid (IPA) as polyvalent carboxylic acids. (1.2802 mol), trimellitic anhydride (TMAn) 3.1 parts (0.0161 mol), 2-methyl-1,3-propanediol (2MPG) 58.4 parts (0 .6480 mol), 140.1 parts (1.3452 mol) of neopentyl glycol (NPG), 102.9 parts (0.1944 mol) of dimer diol "PRIPOL 2033" (P2033) (manufactured by Croda), tetra 0.1 part of butyl titanate was charged, the temperature was raised over 2 hours until the internal temperature reached 260° C., and an esterification reaction was carried out at 260° C. for 1.5 hours. Then, 0.1 part of tetrabutyl titanate was added as a catalyst, the pressure in the system was reduced to 2.5 hPa, and the polymerization reaction was carried out over 2 hours. Thereafter, the inner temperature is lowered to 240° C., 9.0 parts (0.0468 mol) of trimellitic anhydride (TMAn) is added, and depolymerization reaction is performed at 240° C. for 1 hour to obtain a polyester resin (A-1). got

<Production Example 2: Production of polyester resin (A-2)>
A polyester resin (A-2) was obtained in the same manner as in Production Example 1 except that the resin composition was changed as shown in Table 1-A.

Tables 1-A and 1-B show the resin compositions (structural units derived from components) and physical properties of the obtained polyester resins (A-1) and (A-2). The abbreviations in Table 1-A are as follows.
"TPA": terephthalic acid "IPA": isophthalic acid "NDCM": dimethyl 2,6-naphthalenedicarboxylate "TMAn": trimellitic anhydride "EG": ethylene glycol "2MPG": 2-methyl-1,3 - Propanediol "NPG": Neopentyl glycol "TCD-DM": Tricyclodecanedimethanol "P2033": Dimer diol "Pripol 2033" (manufactured by Croda)

<Polyepoxy compound (B)>
The following was prepared as a polyepoxy-based compound (B).
(B-1): Meta-xylenediamine type epoxy resin "TETRAD-X" (manufactured by Mitsubishi Gas Chemical Company, Inc.) (WPE = 98 (g/eq))
(B-2): Glycidylamine type epoxy resin "jER-604" (manufactured by Mitsubishi Chemical Corporation) (WPE = 118 (g/eq))
(B-3): para-aminophenol type epoxy resin "jER-630" (manufactured by Mitsubishi Chemical Corporation) (WPE = 98 (g/eq))
(B-4): Phenolic novolak type epoxy resin "YDPN-638" (manufactured by Nippon Steel Chemical & Materials Co., Ltd.) (WPE = 177 (g / eq))

<Filler (C)>
As the filler (C), the following were prepared.
(C-1): Synthetic mica "Micromica MK-100" (manufactured by Katakura Co-op Agri) (average particle size = 6 µm)
(C-2): Fluorinated polymer powder "EA-2000" (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) (manufactured by AGC) (average particle size = 2 to 3 µm)

[Manufacture of adhesive composition]
Using the polyester resin (A-1), the polyepoxy compound (B) and the filler (C), an adhesive composition was produced as follows.

<Example 1>
3.2 parts of the polyepoxy compound (B-1) (solid content) and 30 parts of the filler (C-1) are added to the polyester resin (A-1) solution (100 parts as solid content), Further, the mixture was diluted with methyl ethyl ketone to a solid content of 40%, stirred and mixed to obtain an adhesive composition.

<Examples 2 to 6, Comparative Examples 1 to 3>
An adhesive composition was obtained in the same manner as in Example 1, except that the resin composition was as shown in Table 2.

The obtained adhesive composition was evaluated as follows. The results are shown in Tables 2 and 3.

[Preparation of laminate]
The adhesive composition prepared above was applied to a 50 μm-thick polyimide film “Kapton 200H” (manufactured by Toray DuPont) with an applicator and then dried at 120° C. for 5 minutes to form an adhesive layer with a dry film thickness of 25 μm. . Next, a rolled copper foil having a thickness of 30 μm is laminated with the adhesive layer surface of the polyimide film with an adhesive layer (lamination conditions: 170 ° C., 0.2 MPa, feed rate 1.5 m / min), and then heat treated in an oven at 160 ° C. for 4 hours. , to obtain a laminate.
For convenience, a laminated body (polyimide film/adhesive layer/rolled copper foil) laminated with a rolled copper foil is referred to as "PI/Cu".

[evaluation]
<Gel fraction>
After the polyimide film with the adhesive layer obtained above was cured by heat treatment at 160° C. for 4 hours, it was cut into a size of 4 cm×4 cm. This was wrapped in a 200-mesh SUS wire mesh, immersed in methyl ethyl ketone at 23° C. for 24 hours, and the weight percentage of the undissolved adhesive component remaining in the wire mesh relative to the weight of the adhesive before immersion was defined as the gel fraction.

<Dispersibility>
After the polyimide film with the adhesive layer obtained above was cured by heat treatment at 160° C. for 4 hours, the obtained adhesive layer was visually checked for resin compatibility and filler dispersibility.
The evaluation criteria were as follows.
A: Dispersed/dissolved and no aggregates are observed B: Dispersed, but fine aggregates are visually observed C: Dispersed, but a large number of aggregates are visually observed D: Not dispersed

<Initial adhesive strength>
A test piece was prepared by cutting the PI/Cu obtained above into a width of 1 cm. The test piece was fixed to a glass plate with a thickness of 2 mm using double-sided tape, and the tensile peel strength (N / cm) of the test piece was measured using a peel tester in an environment of 23 ° C. and 50% RH (peel speed: 50 mm/min, peeling angle: 180°). The evaluation criteria were as follows.
◎: 8 N / cm or more ○: 6 N / cm or more, less than 8 N / cm △: 4 N / cm or more, less than 6 N / cm ×: less than 4 N / cm

<Damp heat durability>
Place the test piece prepared in the same manner as above in a constant temperature and humidity machine at 85 ° C. and 85% RH, remove it after a predetermined time (after 240, 500 or 1000 hours), and place it in an environment of 23 ° C. and 50% RH. After standing overnight, the tensile peel strength (N/cm) was measured in the same manner as the initial adhesive strength described above. The percentage of the adhesive strength after wet heat treatment to the initial adhesive strength was defined as "retention rate (%)".
The absolute value of adhesive strength was evaluated using the same evaluation criteria as those for the initial adhesive strength.
The adhesive force retention rate was evaluated based on the following evaluation criteria.
◎: retention rate of 80% or more ○: retention rate of 60% or more and less than 80% △: retention rate of 40% or more and less than 60% ×: retention rate of less than 40%

<Dielectric constant (Dk)/dielectric loss tangent (Df)>
The adhesive composition prepared above was applied to a PET film having a thickness of 38 μm with an applicator, dried at 120° C. for 5 minutes, and then heat-treated and cured in an oven at 160° C. for 4 hours to prepare a cured film having a thickness of 50 μm. was determined at 10 GHz by the cavity resonator perturbation method using a network analyzer.

<Transmission loss>
The transmission loss of the laminate consists of the sum of the conductor loss and the dielectric loss, and the dielectric loss is proportional to the square root of the dielectric constant (Dk) and dielectric loss tangent (Df) of the dielectric layer.
Therefore, as an evaluation of the effect on transmission loss, the coefficient E of the dielectric loss term of transmission loss was set to the following formula, and the value was calculated from the dielectric constant (Dk) and the dielectric loss tangent (Df) at 10 GHz.
E = (Dk) ^1/2 x Df
The evaluation criteria were as follows. With evaluations A and B, the transmission loss of the laminate is good.
A: E ≤ 0.004
B: 0.004 < E ≤ 0.007
C: 0.007 < E ≤ 0.009
D: 0.009 < E

From the above results, according to the laminate of the present invention and the adhesive composition of the present invention, it is possible to provide a laminate having an adhesive layer with a low transmission loss and a high adhesive strength maintenance rate before and after the wet heat durability test. I know it can be done.

Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application 2021-197875, Japanese Patent Application 2021-197876 and Japanese Patent Application 2021-197877 filed on December 6, 2021, the entirety of which is incorporated by reference.

Claims

A laminate having an adhesive layer on at least one surface of a substrate or a conductor layer,
The adhesive layer is a cured product of an adhesive composition containing a polyester resin (A), a polyepoxy compound (B), and a filler (C),
A laminate in which the dielectric loss tangent (Df) of the adhesive layer at 10 GHz (under an environment of a temperature of 23° C. and a relative humidity of 50% RH) is 0.005 or less.
The laminate according to claim 1, wherein the filler (C) contains fluoropolymer powder (C1) and/or clay mineral (C2).
The content of the polyepoxy compound (B) in the adhesive composition is such that the epoxy equivalent of the polyepoxy compound (B) to the carboxy group of the polyester resin (A) is 0.8 or more and less than 2. The laminate according to claim 1 or 2, which is an amount.
The laminate according to any one of claims 1 to 3, wherein the polyester resin (A) has an acid value of 3 mgKOH/g or more and a glass transition temperature of -5°C or more.
The laminate according to any one of claims 1 to 4, wherein the polyester resin (A) contains structural units derived from polyhydric carboxylic acids and structural units derived from polyhydric alcohols.
The laminate according to claim 5, wherein the polyester-based resin (A) contains a structural unit derived from an aromatic polycarboxylic acid as the structural unit derived from the polyvalent carboxylic acid.
The content of the filler (C) in the adhesive composition is 1 to 100 parts by weight with respect to 100 parts by weight of the polyester resin (A), according to any one of claims 1 to 6. laminate.
The base material is polyimide film, polyether ether ketone film, polyphenylene sulfide film, aramid film, polyethylene naphthalate film, liquid crystal polymer film, polyethylene terephthalate film, polyethylene film, polypropylene film, silicone release treated paper, polyolefin resin coated paper. The laminate according to any one of claims 1 to 7, which is at least one selected from the group consisting of , polymethylpentene film, and fluororesin film.
The laminate according to any one of claims 1 to 8, which is further laminated with a conductor.
A circuit board material having the laminate according to any one of claims 1 to 9.
An adhesive composition containing a polyester resin (A), a polyepoxy compound (B), and a filler (C),
An adhesive composition having a dielectric loss tangent (Df) at 10 GHz (at a temperature of 23° C. and a relative humidity of 50% RH) of 0.005 or less for a cured product of the adhesive composition.
The adhesive composition according to claim 11, wherein the filler (C) contains fluoropolymer powder (C1) and/or clay mineral (C2).
The content of the polyepoxy compound (B) is such that the epoxy equivalent of the polyepoxy compound (B) to the carboxy group of the polyester resin (A) is 0.8 or more and less than 2. The adhesive composition according to 11 or 12
The adhesive composition according to any one of claims 11 to 13, wherein the polyester resin (A) has an acid value of 3 mgKOH/g or more and a glass transition temperature of -5°C or more.
The adhesive composition according to claim 14, wherein the polyester resin (A) has an acid value of 5 mgKOH/g or more and a glass transition temperature of -5°C or more.
The adhesive composition according to any one of claims 11 to 15, wherein the polyester resin (A) contains structural units derived from polyhydric carboxylic acids and structural units derived from polyhydric alcohols.
The adhesive composition according to claim 16, wherein the polyester-based resin (A) contains a structural unit derived from an aromatic polycarboxylic acid as the structural unit derived from the polyvalent carboxylic acid.
The adhesive composition according to any one of claims 11 to 17, wherein the content of said filler (C) is 1 to 100 parts by weight with respect to 100 parts by weight of said polyester resin (A).