JP2021025016A - Thermosetting adhesive composition and laminated film - Google Patents

Abstract

To provide a thermosetting adhesive composition that has a low dielectric constant and a low dielectric loss tangent and that has a high adhesive strength to heat-resistant film.SOLUTION: The thermosetting adhesive composition of the present invention is an adhesive composition containing an oligophenylene ether, a maleimide compound, an epoxy resin, a styrene-based elastomer and a modified polyolefin, and in which the weight ratio of the styrene-based elastomer and the modified polyolefin is 2:1 to 2:3.SELECTED DRAWING: None

Description

The present invention relates to a thermosetting adhesive composition having excellent low dielectric properties and a laminated film on which the thermosetting adhesive composition is laminated.

In recent years, as electronic devices such as portable personal computers and mobile phones have become more sophisticated, smaller, and more multifunctional, there is a strong demand for higher density, smaller size, and thinner electronic components that make up electronic devices. There is. The characteristics required for wiring boards or semiconductor packages, which are constituent materials of electronic components, are also diversifying. For example, a structure capable of three-dimensional wiring is required for a printed wiring board having a limited space. There is an increasing demand for flexible printed wiring boards (hereinafter referred to as FPCs) having this configuration.

In general, FPC has a structure in which a circuit pattern is formed on a copper foil laminated on a plastic film, the circuit pattern is filled with a heat-curable insulating resin, and the circuit pattern is coated with another heat-resistant film. The plastic film has heat resistance and insulating properties typified by polyimide. A film in which an uncured circuit pattern filling resin and a heat-resistant film are integrated in advance is called a coverlay film, and various films have been proposed so far. Further, for high-density mounting, it is widely practiced to multi-layer FPCs, and what is used at the time of multi-layering is a so-called bonding sheet obtained by processing a thermosetting adhesive into a thin sheet.

In FPC manufactured by a general method using a flexible cupper Clad Laminate (hereinafter referred to as FCCL), a coverlay film, and a bonding sheet in which copper foil is laminated on a polyimide film or the like, the copper foil layer is used. Insulation is ensured with the other copper foil layer through a polyimide film or the like.

The coverlay film and the bonding sheet are required to have high adhesive strength with respect to the insulating plastic film which is the FPC base material. To solve this problem, Patent Document 1 proposes a thermosetting adhesive composition having high adhesive strength to a liquid crystal polymer film and a copper foil.

WO2016 / 117554

However, in Patent Document 1, although a certain adhesive strength of the thermosetting adhesive composition to the liquid crystal polymer film is achieved, higher adhesion is achieved depending on the laminate such as FCCL containing the thermosetting adhesive composition. Strength may be required. In addition, a polyimide film (modified polyimide) compatible with next-generation high-speed transmission is also attracting attention as a candidate for a low-dielectric base material along with a liquid crystal polymer film, but this base material generally obtains low-dielectric properties. It is known to be difficult to adhere due to the segment for.
Therefore, an object of the present invention is to provide a thermosetting adhesive composition having a low dielectric constant and a low dielectric loss tangent and having a high adhesive strength with respect to a heat-resistant film.

The present inventors have come to find a thermosetting adhesive composition having high adhesive strength to a heat-resistant film by diligently examining the weight ratios of a styrene-based elastomer and a modified olefin in addition to an organic material having low dielectric properties. It was.
The present invention includes the following forms.
<1> An adhesive composition containing an oligophenylene ether, a maleimide compound, an epoxy resin, a styrene-based elastomer, and a modified polyolefin.
A thermosetting adhesive composition characterized in that the weight ratio of the styrene-based elastomer and the modified polyolefin is 2: 1 to 2: 3.
<2> The thermosetting adhesive composition according to <1>, wherein the weight ratio of the modified polyolefin and the epoxy resin is 10: 1 to 10:10.
<3> The thermosetting adhesive composition according to claim 1 or 2 is laminated on at least one of a copper foil, a heat-resistant film, a release film base material, and a release paper. Laminated film.

The thermosetting adhesive composition according to the present invention has a low dielectric constant and a low dielectric loss tangent, and has excellent adhesiveness to a heat-resistant film.

The present invention will be described in detail below, but the present invention is not limitedly interpreted based on the specific examples described in the specification. The thermosetting adhesive composition (hereinafter, appropriately abbreviated as an adhesive composition) in the present invention contains oligophenylene ether, maleimide compound, epoxy resin, styrene-based elastomer and modified polyolefin as essential components.

<Component (A): Oligophenylene ether>
The oligophenylene ether used in the adhesive composition of the present invention is not particularly limited as long as it is a compound that imparts low dielectric property to the adhesive composition, but typical structures are shown below. The component (A) of the present invention is a vinyl compound having a polyphenylene ether skeleton represented by the structural formula (1). In the present invention, the component (A) mainly contributes to the improvement of thermosetting property, heat resistance and low dielectric property of the adhesive composition.

構造式（１）中、置換基Ｒ^１、Ｒ^２、Ｒ^３およびＲ^４はそれぞれ、水素原子、ハロゲン原子、アルキル基、フェニル基、またはハロアルキル基である。
ハロゲン原子としては、フッ素原子、塩素原子、臭素原子、ヨウ素原子などが挙げられる。

In the structural formula (1), the substituents R ¹ , R ² , R ³ and R ⁴ are hydrogen atoms, halogen atoms, alkyl groups, phenyl groups, or haloalkyl groups, respectively.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

The alkyl group is preferably an alkyl group having 1 to 6 carbon atoms, and the haloalkyl group is preferably a haloalkyl group having 1 to 6 carbon atoms. Further, the substituents R ¹ , R ² , R ³ and R ⁴ are preferably hydrogen atoms or alkyl groups having 1 to 6 carbon atoms, respectively.

X is an organic group having 1 or more carbon atoms and may contain an oxygen atom, a sulfur atom or a halogen atom, and a and d are 0 or 1. As the organic group having 1 or more carbon atoms, an alkyl group having 1 to 6 carbon atoms is preferable.

Y is represented by the structural formula (2), and R ⁵ , R ⁶ , R ⁷ and R ⁸ are hydrogen atoms, halogen atoms, alkyl groups having 1 to 6 carbon atoms, or phenyl groups, respectively, preferably hydrogen. It is an atom or an alkyl group having 1 to 6 carbon atoms. b and c are integers from 0 to 20, both of which are non-zero.

Z is represented by the structural formula (3), and R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are alkyl atoms having hydrogen atoms, halogen atoms and 1 to 6 carbon atoms, respectively. It is a group or a phenyl group, preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
A in the structural formula (3) is a single-bonded or linear, branched or cyclic hydrocarbon group having 1 to 20 carbon atoms, preferably a single-bonded or divalent fat having 1 to 6 carbon atoms. It is a group saturated hydrocarbon group.
Each of the "*" in the structural formulas (2) and (3) indicates a binding site with an oxygen atom in the structural formula (1).

As a preferred form, the component (A) has a structure represented by the following structural formula (4).

上記構造式（４）中、ｂおよびｃは上記の通りである。上記構造式（４）中、Ｙは下記構造式（５）または構造式（５’）のうち１種が配列した、または、２種がランダムで配列した構造を満たすものである。下記構造式（５）および構造式（５’）において、*^１は上記構造式（４）にける酸素原子との結合部位を示し、*^２は上記構造式（４）にける炭素原子との結合部位を示す。

In the structural formula (4), b and c are as described above. In the above structural formula (4), Y satisfies a structure in which one of the following structural formulas (5) or structural formula (5') is arranged or two types are randomly arranged. In the following structural formulas (5) and (5'), * ¹ indicates the binding site with the oxygen atom in the ^{above structural formula (4), and * 2} indicates the binding site with the carbon atom in the above structural formula (4). Indicates the binding site.

上記「Ｙは下記構造式（５）または構造式（５’）のうち１種が配列した、または、２種がランダムで配列した構造を満たすものである」により、上記構造式（４）中、−ＹＯ−が、下記構造式（５）または構造式（５’）のうち１種のみが配列した、または、２種がランダムで配列した構造であることを意味するだけでなく、−ＯＹ−が、下記構造式（５ａ）または構造式（５ａ’）のうち１種のみが配列した、または、２種がランダムで配列した構造であることも包含する。下記構造式（５ａ）および構造式（５ａ’）において、*^１は上記構造式（４）にける酸素原子との結合部位を示し、*^２は上記構造式（４）にける炭素原子との結合部位を示す。

In the above structural formula (4), according to the above "Y satisfies the structure in which one of the following structural formulas (5) or structural formula (5') is arranged or two types are randomly arranged". , -YO- not only means that only one of the following structural formulas (5) or structural formula (5') is arranged, or two types are randomly arranged, but also -OY. -Also includes a structure in which only one of the following structural formulas (5a) or structural formula (5a') is arranged, or two types are randomly arranged. In the following structural formulas (5a) and (5a'), * ¹ indicates a binding site with an oxygen atom in the ^{above structural formula (4), and * 2} indicates a binding site with a carbon atom in the above structural formula (4). Indicates the binding site.

〔成分（Ａ）の分子量〕
構造式（１）で示される化合物の数平均分子量は、５００〜３０００の範囲にあることが好ましく、１０００〜２５００であることがさらに好ましい。数平均分子量は、ゲル透過クロマトグラフィー法により、ポリスチレン標準により測定される。
数平均分子量が５００以上である場合、樹脂組成物を硬化させる工程において、接着剤組成物の粘度が極端に低くなり難く、流れ出しが起こり難くなるため好ましい。また、数平均分子量の下限が５００である成分（Ａ）はビニル基当量が小さくなり過ぎず、反応基数から配合量を決定する際、成分（Ｂ）の必要量が少なくなり、低誘電特性が得られ易くなるため好ましい。
一方、数平均分子量が３０００以下である場合、溶剤への溶解性および他の樹脂との相溶性が高まり、ワニスの安定性が良好で、フィルム状態にした際の外観不良および物性低下が起こり難いため好ましい。

[Molecular weight of component (A)]
The number average molecular weight of the compound represented by the structural formula (1) is preferably in the range of 500 to 3000, and more preferably 1000 to 2500. The number average molecular weight is measured by gel permeation chromatography and polystyrene standards.
When the number average molecular weight is 500 or more, the viscosity of the adhesive composition is unlikely to be extremely low and the outflow is unlikely to occur in the step of curing the resin composition, which is preferable. In addition, the vinyl group equivalent of the component (A) having a lower limit of the number average molecular weight of 500 does not become too small, and the required amount of the component (B) becomes small when determining the blending amount from the number of reactive groups, resulting in low dielectric properties. It is preferable because it is easy to obtain.
On the other hand, when the number average molecular weight is 3000 or less, the solubility in a solvent and the compatibility with other resins are enhanced, the stability of the varnish is good, and poor appearance and deterioration of physical properties are unlikely to occur in a film state. Therefore, it is preferable.

<Component (B): Maleimide compound>
The component (B) of the present invention is a maleimide compound having two or more maleimide groups in the molecule, and is preferably at least one selected from the compound group represented by the structural formulas (6) to (9). is there. In the present invention, the component (B) mainly contributes to the thermosetting property of the adhesive composition. The above-mentioned component (A) and component (B) can be cured by themselves when heated to 200 ° C. or higher, but the reaction temperature can be lowered by coexisting the component (A) and the component (B). Specifically, good characteristics can be obtained by heat treatment at 150 ° C. to 180 ° C.
In the adhesive composition of the present invention, one type of the compound represented by the structural formulas (6) to (9) may be used alone, or two or more types may be mixed and used.

上記式（６）中、Ｒ^１７〜Ｒ^２４はそれぞれ、水素原子または炭素数１〜６のアルキル基である。Ｂは単結合、炭素数１〜２０の２価の炭化水素基、または酸素原子であり、好ましくは、好ましくは炭素数１〜４の２価の脂肪族飽和炭化水素基である。

In the above formula (6), R ^{17 to} R ²⁴ are hydrogen atoms or alkyl groups having 1 to 6 carbon atoms, respectively. B is a single bond, a divalent hydrocarbon group having 1 to 20 carbon atoms, or an oxygen atom, and is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 4 carbon atoms.

上記式（７）中、Ｒ^２５〜Ｒ^３２はそれぞれ、水素原子または炭素数１〜６のアルキル基である。Ｄは炭素数１〜２０の２価の炭化水素基であり、好ましくは下記式（１５）で示される炭化水素基である。

In the above formula (7), R ^{25 to} R ³² are hydrogen atoms or alkyl groups having 1 to 6 carbon atoms, respectively. D is a divalent hydrocarbon group having 1 to 20 carbon atoms, and is preferably a hydrocarbon group represented by the following formula (15).

上記式（１５）中、Ｒ^４４及びＲ^４５はそれぞれ水素原子または炭素数１〜４のアルキル基を示し、Ｆは炭素数１〜４の２価の脂肪族飽和炭化水素基を示し、*は酸素原子との結合部位を示す。

In the above formula (15), R ⁴⁴ and R ⁴⁵ each represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, F represents a divalent aliphatic saturated hydrocarbon group having 1 to 4 carbon atoms, and * indicates a divalent aliphatic saturated hydrocarbon group. The bond site with the oxygen atom is shown.

上記式（８）中、Ｒ^３３〜Ｒ^４３はそれぞれ、水素原子または炭素数１〜６のアルキル基であり、ｐは１〜２０の整数を示す。

In the above formula (8), R ^{33 to} R ⁴³ are hydrogen atoms or alkyl groups having 1 to 6 carbon atoms, respectively, and p represents an integer of 1 to 20.

式（９）中、Ｅは炭素数１〜２０の２価の脂肪族炭化水素基であり、好ましくは炭素数１〜１０の２価の脂肪族飽和炭化水素基である。

In the formula (9), E is a divalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, preferably a divalent aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms.

Specific examples of the structural formulas (6), (7), (8), and (9) include the following structural formulas (10), (11), (12), (13), and (14). In the following structural formula (13), p has the same meaning as p in the above structural formula (8).

〔ビニル基とマレイミド基の比率〕
成分（Ａ）と成分（Ｂ）の配合量は、ビニル基とマレイミド基との当量比を考慮して決定する。すなわち、成分（Ａ）に含まれるビニル基と成分（Ｂ）に含まれるマレイミド基の当量比（ビニル基：マレイミド基）を、１．０：０．５〜１．０：４．０、好ましくは、１．０：０．７５〜１．０：３．５、さらに好ましくは、１．０：１．０〜１．０：３．０に設定する。

[Ratio of vinyl group to maleimide group]
The blending amount of the component (A) and the component (B) is determined in consideration of the equivalent ratio of the vinyl group and the maleimide group. That is, the equivalent ratio (vinyl group: maleimide group) of the vinyl group contained in the component (A) to the maleimide group contained in the component (B) is preferably 1.0: 0.5 to 1.0: 4.0. Is set to 1.0: 0.75 to 1.0: 3.5, more preferably 1.0: 1.0 to 1.0: 3.0.

When the ratio of maleimide groups is smaller than 1.0: 0.5, the component (A) having a low molecular weight remains unreacted in the cured adhesive composition, and the adhesive composition is machined at a high temperature. It is not preferable because it deteriorates the target characteristics. On the other hand, when the ratio of maleimide groups is larger than 1.0: 5.0, the amount of the component (B) in the adhesive composition is large, and the component (B) has a higher dielectric constant than the component (A). It is not preferable because it has a high rate, high dielectric loss tangent, and high moisture absorption rate, and as a result, the electrical characteristics of the adhesive composition and the heat resistance in the soldering process at the time of moisture absorption are lowered.

<Component (C): Epoxy resin>
As the epoxy resin which is the component (C) used in the present invention, a known material can be used. For example, as novolak type epoxy resin, novolak epoxy resin, cresol novolak epoxy resin, etc .: As bisphenol type epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, dicyclopentadiene skeleton-containing epoxy resin, naphthalene skeleton-containing epoxy resin, biphenyl skeleton Epoxy contained, etc .: Other examples include an epoxy resin having a dicyclopentadiene skeleton.

<Component (D): Styrene-based elastomer>
In the present invention, the styrene-based elastomer of the component (D) mainly contributes to the low dielectric property, heat resistance and adhesiveness improvement of the adhesive composition, and the flexibility improvement when the adhesive composition is formed into a film.

The styrene-based elastomer of the component (D) used in the present invention contains a polyolefin skeleton composed of one or more selected from ethylene, propylene, butene, isobutene, butadiene, and isoprene as a main component, and a polyolefin block and a polystyrene block. A thermoplastic elastomer (hereinafter referred to as a thermoplastic elastomer) which is a copolymer of the above can be used.
Specifically, polystyrene-poly (ethylene / propylene) block copolymer, polystyrene-poly (ethylene / butylene) block copolymer, polystyrene-polyisoprene block copolymer, polystyrene-poly (butadiene / butylene) block Polymers, hydrogenated polystyrene-poly (isoprene / butadiene) block copolymers are more preferred, and polystyrene-poly (ethylene / propylene) block copolymers and polystyrene-polyisoprene block copolymers are particularly preferred.

The weight ratio of the styrene unit in the thermoplastic elastomer used in the present invention (hereinafter referred to as styrene content) is 10 to 40% by weight, preferably 10 to 30% by weight, based on the total weight of the thermoplastic elastomer. More preferably, it is 10 to 25% by weight. If the styrene content is less than 10% by weight, the compatibility with other resins is lowered, which is not preferable. If the styrene content is more than 40% by weight, cracks are likely to occur when the adhesive composition is formed into a film. Since the storage elastic modulus E'of the adhesive composition after heat curing becomes high, the flexibility is impaired and the folding resistance is lowered, which is not preferable.

Further, the thermoplastic elastomer used in the present invention shows predetermined values for 100% tensile tensile stress and elongation at cutting measured in accordance with JIS K-6251. The details will be described below. The 100% tensile tensile stress is in the range of 0.1 to 2.9 MPa, preferably 0.2 to 2.7 MPa, more preferably 0.3 to 2.5 MPa. If it is less than 0.1 MPa, the adhesive composition after curing becomes too soft and the required strength as an adhesive cannot be obtained, which is not preferable. If it exceeds 2.9 MPa, the adhesive composition after heat curing becomes rigid. Therefore, the stress relaxation performance becomes small, that is, a large stress is likely to be generated for a small transfer amount, which is not preferable.

The elongation at the time of cutting of the thermoplastic elastomer is 100% or more, preferably 200% or more, more preferably 300% or more, and particularly preferably 400% or more. If it is less than 100%, the flexibility of the adhesive composition is insufficient, so that the thermosetting adhesive film (hereinafter, appropriately abbreviated as "adhesive film") in which the adhesive composition is laminated with another base material is cracked. It is not preferable because it is easy to use and the folding resistance is lowered.

The number average molecular weight of the thermoplastic elastomer used in the present invention is not particularly limited, but is 10,000 to 300,000 from the viewpoint of lowering the storage elastic modulus E'of the adhesive composition and imparting high flexibility. It is preferably 10,000 to 250,000, more preferably 10,000 to 200,000. When the number average molecular weight of the thermoplastic elastomer is 10,000 or more, the flexibility of the adhesive composition can be appropriately obtained, and the strength required for the adhesive can be obtained. On the other hand, when it is 300,000 or less, the storage elastic modulus E'of the adhesive composition does not increase, so that the flexibility is not impaired, the folding resistance of the adhesive composition is unlikely to decrease, and the solvent is used. Solubility and compatibility with other components are maintained, and phase separation is difficult. In the adhesive composition of the present invention, one type of the above-mentioned elastomer may be used alone, or two or more types may be mixed and used.

<Component (E): Modified Polyolefin>
The modified polyolefin of the component (E) used in the present invention is a resin having a portion derived from a polyolefin resin and a graft portion derived from a modifier. Preferably, those obtained by grafting at least one of α, β-unsaturated carboxylic acid and its acid anhydride to at least one of polyethylene, polypropylene and propylene-α-olefin copolymer can be mentioned. The modified polyolefin resin can be produced by graft polymerization by a known method.
Specific examples thereof include maleic anhydride-modified polypropylene, maleic anhydride-modified propylene-ethylene copolymer, maleic anhydride-modified propylene-butene copolymer, maleic anhydride-modified propylene-ethylene-butene copolymer and the like. These acid-modified polyolefins may be used alone or in combination of two or more.
The melting point (Tm) of the modified polyolefin resin (A) is preferably in the range of 50 ° C. to 120 ° C., more preferably in the range of 60 ° C. to 100 ° C., and most preferably in the range of 70 ° C. to 90 ° C. is there. If the melting point (Tm) is less than 50 ° C., the workability at the time of thermocompression bonding is deteriorated, and the work efficiency may be lowered. On the other hand, when the melting point (Tm) exceeds 120 ° C., the fluidity at the time of heat decreases, and the desired adhesive strength cannot be obtained.

The acid value of the modified polyolefin resin is preferably 3 mgKOH / g to 40 mgKOH / g, more preferably 5 mgKOH / g to 30 mgKOH, from the viewpoint of heat resistance and adhesiveness to the resin base material and the metal base material. / g. If the acid value is less than 3 mgKOH / g, the interaction with the adherend may be deteriorated and the adhesive strength may be deteriorated. In addition, the reactivity with other components may deteriorate, and the heat resistance may decrease. If the acid value exceeds 40 mgKOH / g, the reaction with other components cannot be controlled, the stability of the solution is lowered, and the pot life and the storage stability of the adhesive composition are lowered, which is not preferable.

The weight average molecular weight (Mw) of the modified polyolefin resin (E) is preferably in the range of 10,000 to 150,000. More preferably, it is in the range of 50,000 to 100,000. If the weight average molecular weight (Mw) is less than 10,000, the cohesive force is weakened, and the adhesiveness and heat resistance may be deteriorated. Further, if the weight average molecular weight (Mw) exceeds 150,000, the solubility in various solvents is deteriorated and the stability of the coating material is lowered, which is not preferable.

[Ratio of components (A) and (C)]
The weight ratio of the oligophenylene ether of the component (A) and the epoxy resin of the component (C) may be appropriately changed according to the type of each component used and the like, but is preferably 10: 1 to 1: 1. .. When the ratio of the component (C) is larger than 10: 1, the increase in the resin flow of the adhesive composition can be suppressed, and when the ratio of the component (C) is smaller than 1: 1, the dielectric loss tangent of the adhesive composition Can be suppressed from increasing.

[Ratio of components (D) and (E)]
The adhesive composition of the present invention has a weight ratio of the styrene-based elastomer of the component (D) and the modified polyolefin of (E) of 2: 1 to 2: 3. When the weight ratio is in the above range, it is possible to provide an adhesive composition having a suitable solder heat resistance by suppressing an increase in the resin flow of the adhesive composition.
If only the above component (D) is contained, the adhesive strength of the adhesive composition to the heat-resistant film may be insufficient, and if only the above component (E) is contained, the resin flow of the adhesive composition may be insufficient. Problems such as an increase in the amount of resin and deterioration of solder heat resistance may occur.

<Filler>
The adhesive composition of the present invention includes improvements in mechanical strength, adjustment of melting behavior, suppression of surface tack, improvement of plating properties, improvement of adhesiveness of conductive paste, improvement of flame retardancy, adjustment of dielectric properties, etc. Therefore, a filler may be added. Examples of the filler include resin particles, inorganic particles, and fillers made of inorganic fibers, and known fillers can be used.
Specific fillers include acrylic resin, polystyrene resin, styrene-acrylic copolymer, polyethylene resin, epoxy resin, silicone resin, polyvinylidene fluoride, polytetrafluorethylene, and divinylbenzene resin, as resin particles. Phenolic resin, urethane resin, cellulose acetate, nylon, cellulose, benzoguanamine resin, melamine resin, etc .; as inorganic particles, silica, titanium oxide, aluminum oxide, zinc oxide, magnesium oxide, silicon carbide, silicon nitride, boron nitride, barium sulfate, Metal salts such as magnesium sulfate, aluminum hydroxide, magnesium hydroxide, boron nitride, kaolin, clay, talc, zinc flower, lead white, gicrite, quartz, keisou soil, pearlite, bentonite, mica, synthetic mica, etc.; Examples of the fibrous filler include glass fiber, aramid fiber, silicon carbide fiber, alumina fiber and the like.

In order not to impair the low dielectric constant and low dielectric loss tangent characteristics that are the features of the adhesive composition of the present invention, it is effective to use shirasu balloons or nano-sized hollow silica which are inorganic particles. As the above-mentioned filler, one kind may be used alone, or two or more kinds may be used in combination. Regarding the blending amount, when the total volume of the adhesive composition is 100 parts by volume, the preferable blending amount of the filler is 0.1 to 200 parts by volume, more preferably 0.5 to 150 parts by volume, still more preferably. 1 to 100 parts by volume.

<Other additives>
The adhesive composition of the present invention contains, as necessary, known flame retardants, reaction accelerators, cross-linking agents, polymerization inhibitors, coupling agents, thermosetting resins, heat, for the purpose of adjusting various properties. Plastic resins, dyes, pigments, thickeners, lubricants, defoaming agents, UV absorbers and the like can be added.

<Manufacturing method of adhesive composition solution>
The adhesive composition solution of the present invention will be described. The adhesive composition solution of the present invention can be obtained by dissolving or dispersing each component such as the components (A) to (E) which are the raw materials of the adhesive composition of the present invention in a solvent.
Each component of the adhesive composition may be individually dissolved in a solvent and then blended in a predetermined amount of each solution, or a predetermined amount of each component which is a raw material of the adhesive composition is mixed in advance. A solvent may be added to dissolve it.

Examples of the dissolution method include a method in which the adhesive composition and the solvent are mixed in a container equipped with a stirring device and stirred. If you want to shorten the melting time, it is also effective to heat.
In the present invention, the solid content of the adhesive composition solution is preferably set to 10 to 50% by weight, preferably 15 to 40% by weight. When the solid content is 10% by weight or more, the viscosity of the adhesive composition solution is prevented from becoming too low, and for example, a film having a desired thickness and shape is formed without flowing out when applied to a base film. It tends to be easy to do. On the other hand, when the solid content is 50% by weight or less, the viscosity of the adhesive composition solution is prevented from becoming too high, the coating operation becomes easier, the separation and crystallization of each component are prevented, and the adhesive composition is prevented. The storage stability of the solution tends to improve.

The solvent used in the present invention is not particularly limited as long as the adhesive composition is soluble, and even if the solvent does not dissolve the adhesive composition, it can be a solvent that can obtain a uniform dispersion state. It can be used. Specifically, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, toluene, xylene, ethyl acetate, butyl acetate, tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2. -Pyrrolidone, dimethylsulfoxide, ethylene glycol monomethyl ether acetate, propylene glycol dimethyl ether, benzene dioxane, cyclopentyl methyl ether, methylene chloride, chloroform, 1,2-dichloroethane, γ-butyrolactone, cellosolve, butyl cellosobul, carbitol, butyl carbitol And so on. One of the above solvents may be used alone, or two or more of them may be mixed and used. Of these, tetrahydrofuran and toluene are preferably used.

<Applying method of adhesive composition solution>
Next, a method of laminating the adhesive composition of the present invention on a base material such as a plastic film, metal leaf, paper, woven fabric, or non-woven fabric to obtain an adhesive film with a base material (laminated film) will be described. In the present invention, in addition to plastic films, metal foils, papers, woven fabrics, non-woven fabrics, etc., those having a mold release treatment on one or both sides thereof are also referred to as a base material.
The adhesive film with a base material of the present invention may be obtained by applying an adhesive composition solution to a base material and drying it, or an adhesive film is prepared in advance on a release film or a release paper and used as a base material. You may obtain it by pasting it on.

Examples of the method for applying the adhesive composition solution include a normal coating method and a printing method. Specifically, air doctor coating, bar coating, blade coating, knife coating, reverse coating, transfer roll coating, gravure roll coating, kiss coating, cast coating, spray coating, slot orifice coating, calendar coating, dam coating, dip coating. , Die coating and other coatings, intaglio printing such as gravure printing, and stencil printing such as screen printing can be used.

The drying conditions for drying the solvent are not particularly limited, but it is desirable to appropriately adjust the temperature in the range of 60 to 150 ° C. depending on the solvent used. If the temperature is lower than 60 ° C., the solvent tends to remain in the adhesive film, and the temperature of the applied adhesive composition solution decreases as the solvent volatilizes, causing dew condensation, and the resin components are phase-separated or precipitated. It is not preferable because it may occur. If the temperature is higher than 150 ° C., the curing of the adhesive composition proceeds, or the coating film becomes rough due to a sudden temperature rise, which is not preferable. The drying time is not particularly limited, but a treatment of 1 to 10 minutes is preferable in consideration of practicality. The thickness of the adhesive film can be adjusted by the concentration of the adhesive composition solution and the coating thickness.

A release film or a release paper can be laminated on the adhesive film after drying as a separator (protective layer). As the release film or the release paper, any one can be used as long as it does not impair the characteristics of the adhesive film and can be easily peeled off. Specific examples thereof include polyethylene film, polypropylene film, polymethylpentene film, polyethylene terephthalate film released from silicone, polyethylene coated paper, polypropylene coated paper, silicone release paper and the like. The thickness of the separator is preferably 10 to 100 μm in the case of a release film using a plastic film as a base material, and 50 to 200 μm in the case of a release paper using paper as a base material.

When using an adhesive film with a base material having a separator, only the separator is peeled off, and then the adhesive film surface is attached to the adherend. Examples of the form of the adhesive film with a base material include a sheet or a roll. From the viewpoint of productivity, the adhesive composition solution is continuously applied to the base material wound in a roll state using a known coating machine or the like, and the base material to which the adhesive composition solution is applied is placed in a drying furnace. It is passed through and dried at 60 to 150 ° C. for 1 to 10 minutes, and when it comes out of the drying furnace, a protective layer is attached using a roll laminator to form an adhesive film with a base material, which is wound into a roll. It is preferable to store it.

<Curing method of adhesive composition>
When the adhesive composition of the present invention is heated to 150 to 180 ° C., a cured product is obtained. The heating time is 20 minutes to 5 hours, preferably 30 minutes to 2 hours.
The heating method is arbitrary, and for example, a hot air circulation type oven, a press machine, an autoclave, or the like can be used. The cured product of the adhesive composition of the present invention is characterized by having high flexibility even at a low temperature and having a small decrease in elastic modulus even at a high temperature. Specifically, the storage elastic modulus after heat treatment at 180 ° C. for 1 hour has a minimum value of 1 × 10 ⁵ Pa or more and a maximum value of 1 × 10 ⁸ Pa or less in the range of 25 to 150 ° C.

<Application example>
The adhesive composition of the present invention described above can be laminated with a base material and used for various members of FPC in the form of an adhesive film (laminated film). Hereinafter, each application example will be described.

[Bond sheet]
The bonding sheet can be said to be a thermosetting adhesive film in which the adhesive composition of the present invention is laminated on a release film base material.
Among the adhesive films with a base material of the present invention, a release film using a plastic film as a base material or a release paper using paper as a base material can be used as a bonding sheet. The base material used for the bonding sheet is not particularly limited, but a release film having a thickness of 10 to 100 μm or a release paper having a thickness of 50 to 200 μm is preferable.

Specific examples of the release film include a polyethylene film, a polypropylene film, a polymethylpentene film, a polyvinyl chloride film, a release-treated polyethylene terephthalate film, and a release-treated polyethylene naphthalate film. Specific examples of the release paper include polyethylene coated paper, polypropylene coated paper, silicone release paper and the like.
In the case of the bonding sheet, the thickness of the adhesive film can be set arbitrarily, but it is preferably 5 to 50 μm in a dry state, and more preferably 5 to 25 μm.

[Adhesive film with copper foil (FRCC)]
Among the adhesive films with a base material of the present invention, those using a copper foil as a base material can be used as FRCC. That is, FRCC can be said to be a thermosetting adhesive tape in which the adhesive composition of the present invention is laminated on one surface of a copper foil.
The copper foil used for FRCC is not particularly limited, but a copper foil commercially available for use in electronic material parts is preferable. The thickness of the copper foil is preferably 5 to 50 μm, more preferably 9 to 25 μm.
When used for FRCC, the thickness of the adhesive film can be set arbitrarily, but it is preferably 1 to 50 μm in a dry state, and more preferably 1 to 25 μm.

[Coverlay film]
Among the adhesive films with a base material of the present invention, those using a heat-resistant film as a base material can be used as a coverlay film.
The heat-resistant film used for the coverlay film is not particularly limited as long as it has high electrical insulation and is usually used for the coverlay film. Specific examples include polyimide film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyparavanic acid film, polyether ether ketone film, polyphenylene sulfide film, liquid crystal polymer film, syndiotactic polystyrene film, polycarbonate film and the like. Be done. Usually, the strength of the adhesive composition with respect to a heat-resistant film, particularly a polyimide film, tends to be low, but the adhesive composition of the present invention exhibits good adhesive strength.

The thickness of the heat-resistant film may be arbitrarily selected depending on the intended use, but is usually 1 to 50 μm, preferably 3 to 38 μm, and particularly preferably 5 to 25 μm. Further, for the purpose of increasing the adhesion to the adhesive composition, the surface of the heat-resistant film may be treated with a chemical solution, or may be subjected to surface modification treatment such as plasma treatment, corona discharge treatment, sandblasting, etc. Good.
When used for a coverlay film, the thickness of the adhesive film can be set arbitrarily, but it is preferably 5 to 50 μm in a dry state, more preferably 5 to 38 μm, and particularly preferably 5 to 25 μm.

[FCCL with adhesive]
The thermosetting adhesive film with a base material of the present invention is one in which the adhesive composition of the present invention is laminated on one surface of a heat-resistant film base material and has a copper foil layer on the other side. The FCCL with an adhesive having a structure in which the adhesive film of the present invention, the heat-resistant film, and the copper foil are sequentially laminated has a structure in which a bonding sheet is previously laminated on the heat-resistant film surface of the FCCL. ing. By using this FCCL with an adhesive, labor saving and cost reduction in the FPC manufacturing process can be realized.
As the copper foil and the heat-resistant film used for the FCCL with an adhesive of the present invention, those exemplified by the above-mentioned coverlay film and FRCC can be used. As the FCCL, a commercially available one can be used in the present invention. Alternatively, the copper foil and the heat-resistant film may be bonded together using the adhesive film of the present invention.

The thickness of the copper foil is 5 to 50 μm, preferably 9 to 25 μm, and the thickness of the heat resistant film is 1 to 50 μm, preferably 3 to 38 μm, and more preferably 5 to 25 μm. The thickness of the adhesive film can be set arbitrarily, but it is preferably 1 to 50 μm in a dry state, and more preferably 1 to 25 μm.
A liquid crystal polymer film is used as the heat-resistant film in the adhesive composition film with a base material having a structure in which the coverlay film, the adhesive composition film, the heat-resistant film, and the copper foil are sequentially laminated. This will give an FPC material with a lower dielectric constant and a lower dielectric tangent.

<Characteristics of the present invention>
As shown below, the adhesive composition of the present invention has particularly suitable properties as an FPC material for high frequencies, that is, a bonding sheet, a coverlay, FRCC, and an FCCL with an adhesive. The adhesive composition of the present invention exhibits excellent electrical properties, adhesive strength, heat resistance, and flexibility when heated at 150 to 180 ° C. for 30 minutes to 1 hour.
Specifically, the dielectric constant (ε) at a frequency of 10 GHz is 3.0 or less, the dielectric loss tangent (tan δ) is 0.005 or less, and the peel strength with respect to a heat-resistant film (polyimide film) is 8 N / cm or more.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[Manufacturing of adhesive composition solution]
Each component and solvent which are the raw materials of the adhesive composition shown in Tables 1 and 2 were added, and then a thermometer and a stirrer were set in a flask and all the components were dissolved by stirring for 2 hours. Finally, the solution was filtered using a nylon mesh (wire diameter 30 μm, 255 mesh) to obtain an adhesive composition solution. During the work, the liquid temperature was controlled so as not to exceed 30 ° C. In Table 1, "-" indicates that the resin flow was high and the adhesive composition was too thin, so that the adhesive strength could not be measured.

表１、２に記載した各成分の詳細を以下に示す。
成分（Ａ）：
ビニル化合物１：オリゴフェニレンエーテル（構造式（４）で示される化合物）（OPE2St-1200数平均分子量＝1200）
成分（Ｂ）：
ＢＭＩ１：構造式（１０）で示される化合物（4,4’-ジフェニルメタンビスマレイミド）
成分（Ｃ）：
NC3000H：ビフェニル型エポキシ樹脂
成分（Ｄ）：
エラストマー１：ポリスチレン-ポリ（エチレン/プロピレン）ブロック共重合体。スチレン含有量20重量％、100％伸び引張応力＝2.4ＭＰａ、切断時伸び＝670％。
成分（Ｅ１）：
変性ポリオレフィン（Ｅ１） : 無水マレイン酸変性ポリプロピレン
融点７０℃、酸化１５ｍｇＫＯＨ/ｇ、分子量 ７００００
成分（Ｅ２）：
変性ポリオレフィン（Ｅ２） : 無水マレイン酸変性プロピレン−ブテン共重合体
融点８０℃ 酸化２０ｍｇＫＯＨ/ｇ、分子量 ８００００
硬化促進剤：
C11-Z : ２−ウンデシルイミダゾール
溶媒：
THF：テトラヒドロフラン、トルエン

Details of each component listed in Tables 1 and 2 are shown below.
Ingredient (A):
Vinyl compound 1: Oligophenylene ether (compound represented by structural formula (4)) (OPE2St-1200 number average molecular weight = 1200)
Ingredient (B):
BMI1: Compound represented by structural formula (10) (4,4'-diphenylmethanebismaleimide)
Ingredient (C):
NC3000H: Biphenyl type epoxy resin component (D):
Elastomer 1: Polystyrene-poly (ethylene / propylene) block copolymer. Styrene content 20% by weight, 100% elongation tensile stress = 2.4MPa, elongation at cutting = 670%.
Ingredient (E1):
Modified Polyolefin (E1): Maleic anhydride-modified polypropylene Melting point 70 ° C., oxidation 15 mgKOH / g, molecular weight 70000
Ingredient (E2):
Modified Polyolefin (E2): Maleic anhydride-modified propylene-butene copolymer Melting point 80 ° C. Oxidation 20 mg KOH / g, molecular weight 80000
Curing accelerator:
C11-Z: 2-Undecylimidazole solvent:
THF: tetrahydrofuran, toluene

[Manufacturing of adhesive composition film]
An adhesive composition of a 38 μm-thick polyethylene terephthalate film (trade name: Purex A43, manufactured by Teijin DuPont Film Co., Ltd.) that has been mold-released with silicone so that the thickness after drying is 25 μm using an applicator. A product solution was applied. Then, it was dried in a ventilation oven set at 100 ° C. for 5 minutes to obtain an adhesive composition film having a thickness of 25 μm.

[Preparation of evaluation sample]
(1) Preparation of sample for peel strength (adhesive strength) measurement In order to measure the peel strength, the strength against the polyimide (PI) film and the strength against the copper foil are individually measured. A sample in which the copper foils were bonded to each other was used. Here, the reason for independently measuring the peel strength of the two types of base materials is that it may be required to achieve both high adhesiveness to the two types of base materials having different properties. This is because it is necessary to know the exact peel strength. Even if a sample is prepared using PI as one base material and copper foil as the other base material and the peel strength is measured, only the peel strength with respect to either base material can be known, which is not possible. It is enough.

(1-1. Peel test 1): Using a roll laminator for measuring adhesive strength to PI film, PI film (trade name: Vecstar CT-Z, manufactured by Kuraray Co., Ltd.) with a thickness of 25 μm and an adhesive composition film Was laminated. The working conditions at this time were a roll temperature of 120 ° C., a pressurization of 30 N / cm, and a speed of 0.5 m / min.
Next, the same PI film as described above was further laminated to obtain a laminate in which the two PI films were bonded via an adhesive composition.
The above laminate is heat-pressed at 160 ° C x 0.5 MPa x 2 minutes, then heat-cured at 180 ° C x 1 hour in a ventilation oven, cut into 10 mm x 100 mm, and a sample for measuring peel strength against PI film. Was produced.

(1-2. Peel test 2): The above (1) except that the PI film for measuring the adhesive strength to the copper foil was replaced with a copper foil (trade name: FQ-VLP, manufactured by Mitsui Metal Mining Co., Ltd.) having a thickness of 18 μm. -1. Peel test Under the same conditions as 1), a sample for measuring peel strength against copper foil was prepared. The adhesive surface of the copper foil was a shine surface.

(2) Preparation of sample for solder heat resistance test For measuring solder heat resistance temperature when using copper foil Copper foil under the same conditions as (1-2. Peel test 1) except that the cutting size was changed to 25 mm x 25 mm. A sample for measuring the heat resistant temperature of solder when a film was used was prepared.

(3) Preparation of Sample for Measurement of Dielectric Permittivity and Dielectric Dissipation Factor Using a roll laminator, adhesive composition films having a thickness of 25 μm were sequentially laminated to obtain an adhesive composition having a thickness of 200 μm.
Next, this was heat-cured in a ventilation oven at 180 ° C. for 1 hour, and then cut into 2 mm × 50 mm to prepare a sample for measuring the dielectric constant and the dielectric loss tangent.
At the time of laminating and heat curing, the work was carried out with the Purex A43 laminated on both sides of the adhesive composition, and the Purex A43 was removed immediately before the measurement.

(4) Preparation of sample for resin flow measurement A hole is punched in the adhesive composition film using a hole punch (punch hole diameter 6 mm), and a 25 μm-thick PI film (trade name: Vecstar CT) is used using a roll laminator. -Z. Made by Kuraray Co., Ltd.) and the adhesive composition film were laminated. The working conditions at this time were a roll temperature of 120 ° C., a pressurization of 30 N / cm, and a speed of 0.5 m / min. Next, a copper foil having a thickness of 18 μm (trade name: FQ-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) was further laminated to obtain a laminate in which two films were bonded via an adhesive composition. The center of the punched hole portion of the laminate was marked and a cross line was drawn, and the diameter of the punched hole was measured with a microscope. The above laminate was heat-pressed at 175 ° C. × 0.5 MPa × 2 minutes, and the length of the pores reduced by the exudation of the adhesive composition was measured with a microscope.

[Evaluation details and criteria]
(1) Measurement of peel strength (adhesive strength) The base material was peeled off in the 90 ° direction using a universal tensile tester (manufactured by Olintec Corporation), and the peel strength was measured. The tensile speed was 50 mm / min.
For the PI film and copper foil, a case of 8 N / cm or more was judged to be good, and a case of less than 5 N / cm was judged to be bad.
(2) Solder heat resistance test The sample was humidity-controlled at 20 ° C./65% RH / 96 hours, and then floated in a solder bath at 260 ° C., 280 ° C., and 300 ° C. for 60 seconds.
The temperature at which no abnormality occurred during the float for 60 seconds was defined as the solder heat resistant temperature. If it is 280 ° C, it can be used without any problem, and if it is 300 ° C, it can be judged to be excellent.
(3) Measurement of permittivity and dielectric loss tangent The permittivity (ε) and dielectric loss tangent (tan δ) at 10 GHz were measured by the cavity resonator perturbation method.
(4) Resin flow The value of the difference between the measured length before pressing and the length after pressing / 2 was calculated. If it is 0.4 mm or less, it can be used without problems, and if it is 0.3 mm or less, it can be judged to be excellent. If it is 0.5 mm or more, it is judged to be defective in actual use.

<Evaluation result>
Examples 1 to 4, Comparative Examples 1 to 5:
In Examples 1 to 4, the weight ratio of the styrene oligomer of the component (D) to the modified polyolefin of the component (E1) or (E2) was changed, which was good at 8 N / cm or more with respect to PI, which is a heat-resistant film. Peel strength is obtained, demonstrating the usefulness of the present invention. In Comparative Example 1, the weight ratio of the modified polyolefin is high, that is, component (D): component (E1) = 1: 2. In this case, the solder heat resistance was less than 260 ° C., and the resin flow was as low as 0.4. On the other hand, in Comparative Example 2, the weight ratio of the modified polyolefin is low, that is, component (D): component (E1) = 10: 1. In this case, the adhesive strength to PI was low, and the effect of the inappropriate ratio of modified polyolefin was confirmed.

Further, in Comparative Example 3, when the component (D): the component (E1) = 1: 5, the adhesive strength against PI is lower than that of Comparative Example 1, and the solder heat resistance is inferior. The flow has deteriorated.
In Comparative Example 4, the ratio of the component (D) is 0, and when the component (D) is not used, there is a demerit that the resin flow is very high. In Comparative Example 5, when the component (E1) or (E2) was not used, the adhesive strength against PI was a very low value.

Examples 5-11:
In Examples 5 and 6, when the weight ratio of the component (C) to the component (A) was changed, good adhesive strength to PI was confirmed in each case. On the other hand, in Examples 7 and 8, when the weight ratio of the component (C) was set to 1 and 50, respectively, the adhesive strength to PI was within the permissible range, but the solder heat resistance was higher in Examples 5 and 6. Was a good result.
In Examples 9 to 11, the weight ratios of the curing accelerator, the component (B), and the component (A) were changed, but good results were obtained in terms of both PI adhesive strength and solder heat resistance.

Claims (3)

An adhesive composition containing an oligophenylene ether, a maleimide compound, an epoxy resin, a styrene-based elastomer, and a modified polyolefin.
A thermosetting adhesive composition characterized in that the weight ratio of the styrene-based elastomer and the modified polyolefin is 2: 1 to 2: 3. The thermosetting adhesive composition according to claim 1, wherein the weight ratio of the modified polyolefin and the epoxy resin is 10: 1 to 10:10. A laminated film characterized in that the thermosetting adhesive composition according to claim 1 or 2 is laminated on at least one of a copper foil, a heat-resistant film, a release film base material, and a release paper.