JP2020012026A - Adhesive composition, laminate, and adhesive sheet - Google Patents

Abstract

To provide an adhesive composition which has good adhesiveness to a substrate such as an LCP and is excellent in low dielectric characteristics.SOLUTION: The adhesive composition contains (A) a bismaleimide resin represented by general formula (1), (B) an epoxy resin, and (C) a curing agent. The epoxy resin (B) contains at least one epoxy resin selected from the group consisting of polyfunctional epoxy resins having a bisphenol A skeleton, a bisphenol F skeleton, and a novolac skeleton. The content of the component (B) is 15-35 pts.mass based on 100 pts.mass of the total amount of the component (A) and the component (B). [In the formula (1), Rrepresents a divalent hydrocarbon group derived from a dimer acid; Q represents a substituted or unsubstituted C1-100 aliphatic group, a substituted or unsubstituted aromatic group, or a substituted or unsubstituted heteroaromatic group; and n represents an integer of 0-100.]SELECTED DRAWING: None

Description

  The present invention relates to an adhesive composition, a laminate, and an adhesive sheet. More specifically, the present invention relates to an adhesive composition used for bonding a resin substrate and a resin substrate or a metal substrate, and particularly has a low dielectric property such as a liquid crystal polymer (hereinafter abbreviated as “LCP”). The present invention relates to an adhesive composition used for bonding to a substrate.

  In recent years, with the increase in the speed of transmission signals in printed wiring boards, the frequency of signals has been increasing. Along with this, there has been an increasing demand for flexible printed wiring boards (hereinafter abbreviated as “FPC”) to have low dielectric properties (low dielectric constant and low dielectric loss tangent) in a high frequency range. In response to such demands, as a substrate film used for FPC, instead of conventional polyimide (PI) and polyethylene terephthalate films, LCP having low dielectric properties, syndiotactic polystyrene (SPS), polyphenylene sulfide (PPS) ) Has been proposed.

  However, since the base film having low dielectric properties has low polarity, when a conventional epoxy-based adhesive or acrylic-based adhesive is used, the adhesive strength is weak, and the FPC member such as a cover lay film and a laminated board is used. Fabrication was difficult. Further, epoxy adhesives and acrylic adhesives have a problem that they are not excellent in low dielectric properties and impair the dielectric properties of FPC.

  On the other hand, polyolefin resins are known to have low dielectric properties. Therefore, an FPC adhesive composition using a polyolefin resin has been proposed. For example, Patent Document 1 proposes a modified polyamide adhesive composition into which an olefin skeleton has been introduced in order to enhance the electrical characteristics of FPC. Patent Literature 2 proposes an adhesive using an aromatic olefin oligomer-type modifier and an epoxy resin and a coverlay for a flexible printed wiring board.

JP 2007-284515 A JP 2007-63306 A

  However, the adhesive compositions described in Patent Literatures 1 and 2 have a problem in that, although adhesiveness with a polyimide film is obtained, it is difficult to obtain adhesiveness with a base film having low dielectric properties such as LCP. is there. Further, the adhesive compositions described in Patent Documents 1 and 2 have a problem that the dielectric properties are inferior.

  When an LCP base material is used, there is a method in which the LCP is melted without using an adhesive and is bonded to a copper foil to produce a two-layer substrate. However, this method has a problem that a device or a base for bonding at a high temperature is required, and wrinkles are apt to be formed during processing, and the yield is reduced.

  The present invention has been made in view of the above-mentioned problems of the related art, and has an adhesive composition having good adhesiveness to a substrate such as LCP, and also having excellent low dielectric properties. An object is to provide a laminate and an adhesive sheet.

  The present inventors have conducted intensive studies in order to solve the above problems, and as a result, containing a specific bismaleimide resin having a structure derived from dimer acid, and an epoxy resin having a specific structure at a specific ratio. Further, the present invention has found that an adhesive composition containing a curing agent exhibits excellent low dielectric properties and has high adhesiveness to a resin base material having low dielectric properties such as LCP. It was completed.

［式（１）中、Ｒ^１はダイマー酸に由来する２価の炭化水素基を示し、Ｑは置換又は非置換の炭素数１〜１００の脂肪族基、置換又は非置換の芳香族基、或いは、置換又は非置換のヘテロ芳香族基を示し、ｎは０〜１００の整数を示す。］
［２］上記（Ｃ）成分が、ホスフィン化合物、ホスホニウム塩化合物及びイミダゾール化合物からなる群より選択される少なくとも１種を含有する、上記［１］に記載の接着剤組成物。
［３］上記（Ｃ）成分の含有量が、上記（Ａ）成分及び（Ｂ）成分の総量１００質量部に対して０．１〜５．０質量部である、上記［１］又は［２］に記載の接着剤組成物。
［４］樹脂基材と、樹脂基材又は金属基材との接着に用いられる、上記［１］〜［３］のいずれかに記載の接着剤組成物。
［５］基材と、該基材上に上記［１］〜［４］のいずれかに記載の接着剤組成物を用いて形成された接着剤層と、を備える積層体。
［６］上記［１］〜［４］のいずれかに記載の接着剤組成物によって接着された、樹脂基材と、樹脂基材又は金属基材とを備える積層体。
［７］上記［５］又は［６］に記載の積層体を備える接着シート。 That is, the present invention provides the following inventions.
[1] (A) A bismaleimide resin represented by the following general formula (1), (B) an epoxy resin, and (C) a curing agent, wherein the (B) epoxy resin has a bisphenol A skeleton , An epoxy resin having a bisphenol F skeleton, and at least one epoxy resin selected from the group consisting of a polyfunctional epoxy resin having a novolak skeleton, wherein the content of the component (B) is The adhesive composition, wherein the total amount of the component (A) and the component (B) is 15 to 35 parts by mass based on 100 parts by mass.

[In the formula (1), R ¹ represents a divalent hydrocarbon group derived from dimer acid, Q represents a substituted or unsubstituted aliphatic group having 1 to 100 carbon atoms, a substituted or unsubstituted aromatic group, Alternatively, it represents a substituted or unsubstituted heteroaromatic group, and n represents an integer of 0 to 100. ]
[2] The adhesive composition according to the above [1], wherein the component (C) contains at least one selected from the group consisting of a phosphine compound, a phosphonium salt compound, and an imidazole compound.
[3] The above-mentioned [1] or [2], wherein the content of the component (C) is 0.1 to 5.0 parts by mass based on 100 parts by mass of the total of the components (A) and (B). ] The adhesive composition as described in the above.
[4] The adhesive composition according to any one of [1] to [3], which is used for bonding a resin substrate and a resin substrate or a metal substrate.
[5] A laminate comprising a base material and an adhesive layer formed on the base material using the adhesive composition according to any one of [1] to [4].
[6] A laminate comprising a resin substrate and a resin or metal substrate bonded by the adhesive composition according to any one of [1] to [4].
[7] An adhesive sheet comprising the laminate according to the above [5] or [6].

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition which has favorable adhesiveness with base materials, such as LCP, and is excellent also in low dielectric property, a laminated body and an adhesive sheet using the same can be provided.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments.

[Adhesive composition]
The adhesive composition of the present embodiment includes (A) a bismaleimide resin represented by the general formula (1) (hereinafter, also referred to as “(A) component”) and (B) an epoxy resin (hereinafter, “(B) ) Component) and (C) a curing agent (hereinafter, also referred to as “component (C)”). In the adhesive composition of the present embodiment, the component (B) is selected from the group consisting of an epoxy resin having a bisphenol A skeleton, an epoxy resin having a bisphenol F skeleton, and a polyfunctional epoxy resin having a novolak skeleton. At least one epoxy resin. Further, in the adhesive composition of the present embodiment, the content of the component (B) is 15 to 35 parts by mass, where the total amount of the components (A) and (B) is 100 parts by mass. Further, the adhesive composition of the present embodiment may contain (D) an organic solvent (hereinafter, also referred to as “component (D)”).

<(A) component: bismaleimide resin>
(A) Bismaleimide resin is a compound represented by the following general formula (1), and is obtained by reacting dimer diamine, which is a diamine derived from dimer acid, with tetracarboxylic dianhydride and maleic anhydride. Obtainable.

式（１）中、Ｒ^１はダイマー酸に由来する２価の炭化水素基を示し、Ｑは置換又は非置換の炭素数１〜１００の脂肪族基、置換又は非置換の芳香族基、或いは、置換又は非置換のヘテロ芳香族基を示し、ｎは０〜１００の整数を示す。式（１）中のＱは、ＬＣＰ等の低誘電特性を有する樹脂基材に対するより優れた接着性、及び、より優れた低誘電特性を得る観点から、非置換の芳香族基であることが好ましい。また、式（１）中のｎは、ＬＣＰ等の低誘電特性を有する樹脂基材に対するより優れた接着性、及び、より優れた低誘電特性を得る観点から、５〜３０の整数であることが好ましい。

In the formula (1), R ¹ represents a divalent hydrocarbon group derived from dimer acid, and Q represents a substituted or unsubstituted aliphatic group having 1 to 100 carbon atoms, a substituted or unsubstituted aromatic group, or , A substituted or unsubstituted heteroaromatic group, and n represents an integer of 0 to 100. Q in the formula (1) may be an unsubstituted aromatic group from the viewpoint of obtaining better adhesiveness to a resin substrate having low dielectric properties such as LCP and obtaining better low dielectric properties. preferable. Further, n in the formula (1) is an integer of 5 to 30 from the viewpoint of obtaining better adhesion to a resin base material having low dielectric properties such as LCP and obtaining better low dielectric properties. Is preferred.

  The dimer diamine is, for example, a compound derived from dimer acid, which is a dimer of unsaturated fatty acid such as oleic acid, as described in JP-A-9-12712. In the present embodiment, a known dimer diamine can be used without any particular limitation. For example, a compound represented by the following general formula (3) and / or general formula (4) is preferable.

  In the formulas (3) and (4), p, q, r and s each represent one or more integers selected so that p + q = 6 to 17 and r + s = 8 to 19; There may be. In the formulas (3) and (4), the bond indicated by a broken line means a carbon-carbon single bond or a carbon-carbon double bond. However, when the bond shown by the broken line is a carbon-carbon double bond, the formulas (3) and (4) indicate the number of hydrogen atoms bonded to each carbon atom constituting the carbon-carbon double bond by the formula The structure is obtained by subtracting one from the numbers shown in (3) and (4).

As dimer diamine, the solubility of the resulting bismaleimide resin in an organic solvent, and the heat resistance of the adhesive composition when the bismaleimide resin is used as a material for the adhesive composition, heat-resistant adhesion, low viscosity, etc. From the viewpoint, those represented by the above general formula (4) are preferred, and compounds represented by the following formula (4-1) are particularly preferred.

  Commercial products of dimer diamine include, for example, PRIAMINE 1075 and PRIAMINE 1074 (both manufactured by Croda Japan KK).

  Examples of the tetracarboxylic dianhydride include pyromellitic anhydride; 1,2,3,4-cyclobutanetetracarboxylic dianhydride; 1,4,5,8-naphthalenetetracarboxylic dianhydride; 4,9,10-perylenetetracarboxylic dianhydride; bicyclo (2.2.2) oct-7-ene-2,3,5,6-tetracarboxylic dianhydride; diethylenetriaminepentaacetic dianhydride; Ethylenediaminetetraacetic acid dianhydride; 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride; 3,3', 4,4'-biphenyltetracarboxylic dianhydride; 4,4'-oxydi Phthalic anhydride; 3,3 ', 4,4'-diphenylsulfonetetracarboxylic dianhydride; 2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride 4,4′-bisphenol A diphthalic anhydride; 5- (2,5-dioxytetrahydro) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride; ethylene glycol bis (trimellitic anhydride) Hydroquinone diphthalic anhydride; allyl nadic anhydride; 2-octen-1-yl succinic anhydride; 1,2,3,6-tetrahydrophthalic anhydride; 3,4 5,6-tetrahydrophthalic anhydride and the like. Among them, pyromellitic anhydride is preferred from the viewpoint of heat resistance. These can be used alone or in combination of two or more.

  (A) The weight average molecular weight of the bismaleimide resin is preferably 3,000 to 70,000 from the viewpoint of obtaining better adhesion to a resin base material having low dielectric properties such as LCP, and more excellent low dielectric properties. Preferably, it is 5,000 to 50,000, more preferably 7000 to 30,000.

  As the bismaleimide resin (A), a commercially available compound can be used. Specifically, for example, DESIGNER MOLECURES Inc. BMI-3000 (synthesized from dimer diamine, pyromellitic dianhydride and maleic anhydride), BMI-1500, BMI-1700, BMI-5000 and the like can be suitably used.

<(B) component: epoxy resin>
(B) The epoxy resin includes at least one epoxy resin selected from the group consisting of an epoxy resin having a bisphenol A skeleton, an epoxy resin having a bisphenol F skeleton, and a polyfunctional epoxy resin having a novolak skeleton. (B) The epoxy resin may be composed of only the specific epoxy resin, or may further include another epoxy resin other than the specific epoxy resin.

  Examples of the epoxy resin having a bisphenol A skeleton and the epoxy resin having a bisphenol F skeleton include a compound represented by the following general formula (2). The epoxy resin having a bisphenol A skeleton and the epoxy resin having a bisphenol F skeleton are epoxy resins represented by the following general formula (2-1) from the viewpoint of obtaining better adhesion to a substrate such as LCP. Is preferred.

式（２）及び式（２−１）中、Ｒ^２は水素原子又はメチル基を示し、Ｒ^３は２価の有機基を示し、ｍは０〜３０の整数を示す。式（２）及び式（２−１）中のｍは、ＬＣＰ等の低誘電特性を有する樹脂基材に対するより優れた接着性、及び、より優れた低誘電特性を得る観点から、０〜１０の整数であることが好ましい。式（２）のＲ^３としては、置換又は非置換のアルキレン基、置換又は非置換のアルキレンオキシド基、置換又は非置換の芳香族基等が挙げられる。Ｒ^３が置換又は非置換のアルキレン基、或いは、置換又は非置換のアルキレンオキシド基である場合、エポキシ樹脂に低弾性を付与することができる。

In the formulas (2) and (2-1), R ² represents a hydrogen atom or a methyl group, R ³ represents a divalent organic group, and m represents an integer of 0 to 30. M in the formulas (2) and (2-1) is from 0 to 10 from the viewpoint of obtaining better adhesiveness to a resin base material having low dielectric properties such as LCP and obtaining more excellent low dielectric properties. Is preferably an integer. Examples of R ^{3 in the} formula (2) include a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene oxide group, and a substituted or unsubstituted aromatic group. When R ³ is a substituted or unsubstituted alkylene group or a substituted or unsubstituted alkylene oxide group, low elasticity can be imparted to the epoxy resin.

  Examples of the polyfunctional epoxy resin having a novolak skeleton include compounds having a structural unit represented by the following general formula (5) or (6). For example, a novolak epoxy resin, a naphthalene skeleton modified novolak epoxy resin, a biphenyl novolak Epoxy resin and cresol novolak epoxy resin. The number of epoxy groups in the polyfunctional epoxy resin having a novolak skeleton is preferably 3 or more, and more preferably 5 or more. A in the following general formula (5) is preferably an unsubstituted aromatic group such as a naphthalene skeleton and a biphenyl skeleton from the viewpoint of low dielectric properties.

式（５）及び式（６）中、Ｒ^４は水素原子又はメチル基を示し、Ａは置換又は非置換の炭素数１〜３０の脂肪族基、置換又は非置換の芳香族基、或いは、置換又は非置換のヘテロ芳香族基を有する２価の有機基を示し、ｘ及びｙは各々独立に１以上の整数を示す。ｘが２以上である場合、複数存在するＲ^４は同一でも異なっていてもよい。ｙが２以上である場合、複数存在するＡは同一でも異なっていてもよい。

In the formulas (5) and (6), R ⁴ represents a hydrogen atom or a methyl group, and A represents a substituted or unsubstituted aliphatic group having 1 to 30 carbon atoms, a substituted or unsubstituted aromatic group, or It represents a divalent organic group having a substituted or unsubstituted heteroaromatic group, and x and y each independently represent an integer of 1 or more. When x is 2 or more, a plurality of R ⁴ may be the same or different. When y is 2 or more, a plurality of A may be the same or different.

  As the epoxy resin (B), a liquid bisphenol A epoxy resin or a liquid bisphenol F epoxy resin is preferably used from the viewpoint of compatibility with the (A) bismaleimide resin.

  The content of the (B) epoxy resin is 15 to 35 parts by mass, preferably 15 to 30 parts by mass, and preferably 20 to 25 parts by mass based on 100 parts by mass of the total of the components (A) and (B). Is more preferable. When the content of the component (B) is 15 parts by mass or more, excellent adhesive strength to the LCP substrate can be obtained, and when the content is 35 parts by mass or less, excellent low dielectric properties can be obtained. it can.

<(C) component: curing agent>
(C) The curing agent is not particularly limited, and examples thereof include a phosphine compound, a phosphonium salt compound, and an imidazole compound. These can be used alone or in combination of two or more. Among them, a phosphonium salt compound or an imidazole compound is preferable because it has a particularly excellent function as a catalyst.

  Examples of the phosphine compound include primary phosphines such as alkyl phosphines such as ethyl phosphine and propyl phosphine and phenyl phosphines; dialkyl phosphines such as dimethyl phosphine and diethyl phosphine; diphenyl phosphines such as diphenyl phosphine, methyl phenyl phosphine and ethyl phenyl phosphine; Graded phosphines; trialkylphosphines such as trimethylphosphine, triethylphosphine, tributylphosphine, trioctylphosphine, tricyclohexylphosphine, triphenylphosphine, alkyldiphenylphosphine, dialkylphenylphosphine, tribenzylphosphine, tolylphosphine, tri-p- Styrylphosphine, tris (2,6-dimethoxyphenyl) phosphine, tri-4-meth Le triphenylphosphine, tri-4-methoxyphenyl phosphine, such as tertiary phosphines such as tri-2-cyanoethyl phosphine. Of these, tertiary phosphines are preferably used. These can be used alone or in combination of two or more.

  Examples of the phosphonium salt compound include compounds having tetraphenylphosphonium, alkyltriphenylphosphonium, tetraalkylphosphonium, and the like.Specifically, tetraphenylphosphonium-thiocyanate, tetraphenylphosphonium-tetra-p-methylphenylborate, butyl Triphenylphosphonium-thiocyanate, tetraphenylphosphonium-phthalic acid, tetrabutylphosphonium-1,2-cyclohexyldicarboxylic acid, tetrabutylphosphonium-1,2-cyclohexyldicarboxylic acid, tetrabutylphosphonium-lauric acid and the like. Can be

  Examples of the imidazole compound include 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 2,4-dimethylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-vinyl-2- Methylimidazole, 1-propyl-2-methylimidazole, 2-isopropylimidazole, 1-cyanomethyl-2-methyl-imidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazo Le, 1-cyanoethyl-2-phenylimidazole, and the like. Among them, 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole and 2-ethyl-4-methylimidazole are preferred. By using these compounds, there is obtained an advantage that the reaction of the (A) bismaleimide resin is further promoted, and the heat resistance of the obtained cured product is improved. These can be used alone or in combination of two or more.

  (C) The content of the curing agent is not particularly limited, but from the viewpoint of further improving the adhesiveness to a substrate such as LCP and the heat resistance of the obtained cured product, the bismaleimide resin (A) It is preferably from 0.1 to 5.0 parts by mass, more preferably from 1.0 to 3.0 parts by mass, based on 100 parts by mass of the total amount of the component (B) and the epoxy resin.

<(D) component: organic solvent>
The adhesive composition of the present embodiment can further contain (D) an organic solvent. The organic solvent used in the present embodiment is not particularly limited as long as it dissolves (A) a bismaleimide resin, (B) an epoxy resin, and (C) a curing agent. (D) Specific examples of the organic solvent include, for example, aromatic hydrocarbons such as benzene, toluene, xylene and mesitylene; aliphatic hydrocarbons such as hexane, heptane, octane and decane; cyclohexane, cyclohexene, methylcyclohexane and ethylcyclohexane. Alicyclic hydrocarbons such as hexane; halogenated hydrocarbons such as trichloroethylene, dichloroethylene, chlorobenzene, and chloroform; alcohols such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, and phenol Solvents; ketone solvents such as acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isophorone and acetophenone; cell solvents such as methyl cellosolve and ethyl cellosolve Ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, and butyl formate; ethylene glycol mono n-butyl ether, ethylene glycol mono iso-butyl ether, ethylene glycol mono tert-butyl ether, diethylene glycol mono n-butyl ether; Glycol ether solvents such as diethylene glycol mono iso-butyl ether, triethylene glycol mono n-butyl ether, and tetraethylene glycol mono n-butyl ether can be used. These can be used alone or in combination of two or more. A preferred embodiment is an aromatic hydrocarbon, and among them, toluene or xylene is preferably used.

  The preparation of the adhesive composition of the present embodiment is performed according to a generally employed method. Examples of the preparation method include methods such as melt mixing, powder mixing, and solution mixing. In this case, other than the essential components of the present embodiment, for example, an inorganic filler, a release agent, a flame retardant, an ion trapping agent, an antioxidant, an adhesion imparting agent, a low stress agent, a coloring agent, a coupling agent Agents and the like may be blended within a range that does not impair the effects of the present invention.

<Inorganic filler>
The inorganic filler is added for lowering the coefficient of thermal expansion of the adhesive composition and improving the moisture resistance reliability. Examples of the inorganic filler include fused silica, crystalline silica, silica such as cristobalite, alumina, silicon nitride, aluminum nitride, boron nitride, titanium oxide, glass fiber, and magnesium oxide. The average particle size and shape of these inorganic fillers can be selected according to the application. Among them, spherical alumina, spherical fused silica, glass fiber and the like are preferable.

<Release agent>
The release agent is added to improve the releasability from the mold. Examples of the release agent include carnauba wax, rice wax, candelilla wax, polyethylene, polyethylene oxide, polypropylene, montanic acid, montanic acid and saturated alcohol, 2- (2-hydroxyethylamino) ethanol, ethylene glycol, and glycerin. All known compounds such as montan wax, stearic acid, stearic acid ester, stearic acid amide, etc., which are ester compounds with these compounds can be used.

<Flame retardant>
Flame retardants are added to impart flame retardancy. Any known flame retardant can be used and is not particularly limited. Examples of the flame retardant include a phosphazene compound, a silicone compound, zinc-molybdate-supported talc, zinc-molybdate-supported zinc oxide, aluminum hydroxide, magnesium hydroxide, and molybdenum oxide.

<Ion trap agent>
The ion trapping agent is added in order to capture ionic impurities contained in the liquid adhesive composition and prevent thermal deterioration and moisture absorption deterioration. Any known ion trapping agent can be used and is not particularly limited. Examples of the ion trapping agent include hydrotalcites, bismuth hydroxide compounds, and rare earth oxides.

[Laminate]
The laminate of the present embodiment is obtained by laminating an adhesive composition on a substrate (two-layer laminate of a substrate / adhesive layer) or by further laminating a substrate (substrate / adhesive layer) / Three-layer laminate of base material). Here, the adhesive layer refers to a layer of the adhesive composition after the adhesive composition of the present embodiment is applied to a substrate and dried. The laminate of the present embodiment can be obtained by applying and drying the adhesive composition of the present embodiment to various substrates in accordance with a conventional method, and further laminating another substrate.

<Substrate>
In the present embodiment, the substrate is not particularly limited as long as the adhesive composition of the present embodiment can be applied and dried to form an adhesive layer. , A metal substrate such as a metal plate and a metal foil, and papers.

  Examples of the material of the resin substrate include polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, and fluorine resin. Preferably, the resin substrate is a film-like resin (hereinafter, also referred to as a “substrate film layer”).

  Any conventionally known conductive material that can be used for a circuit board can be used as the metal substrate. Examples of the material include various metals such as SUS, copper, aluminum, iron, steel, zinc, and nickel, and respective alloys, plated products, metals treated with other metals such as zinc or chromium compounds, and the like. . The metal substrate is preferably a metal foil, more preferably a copper foil. The thickness of the metal foil is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, and further preferably 10 μm or more. Further, the thickness of the metal foil is preferably 50 μm or less, more preferably 30 μm or less, and further preferably 20 μm or less. If the thickness is too small, it may be difficult to obtain sufficient electrical performance of the circuit, while if the thickness is too large, the processing efficiency or the like during circuit fabrication may decrease. The metal foil is usually provided in the form of a roll, but the form of the metal foil used when manufacturing a printed wiring board as described below is not particularly limited. When a ribbon-shaped metal foil is used, its length is not particularly limited. The width is not particularly limited, but is preferably about 250 to 500 cm.

  Examples of papers include high quality paper, kraft paper, roll paper, glassine paper, and the like. Further, as the composite material, glass epoxy or the like can be exemplified.

  From the viewpoint of the adhesive force with the adhesive composition and durability, as the material of the base material, polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, Fluorine-based resin, SUS steel plate, copper foil, aluminum foil, or glass epoxy is preferable.

<Adhesive sheet>
The adhesive sheet of the present embodiment includes the above-described laminate, and is, for example, a laminate of the above-described laminate and a release substrate via an adhesive composition. As a specific configuration mode, a laminate (substrate / adhesive layer) / release substrate, laminate (substrate / adhesive layer / substrate) / adhesive layer / release substrate, or release Base material / adhesive layer / laminate (base material / adhesive layer / base material) / adhesive layer / release base material. By laminating the release base material, it functions as a protective layer of the adhesive layer constituting the adhesive sheet. In addition, by using the release substrate, the release substrate can be released from the adhesive sheet, and the adhesive layer can be transferred to another substrate.

  The adhesive sheet of the present embodiment can be obtained by applying and drying the adhesive composition of the present embodiment to various laminates according to a conventional method. In addition, after drying, when a release substrate is attached to the adhesive layer, it can be wound up without causing set-off to the base material that constitutes the laminate, and it is excellent in operability and the adhesive layer is Because it is protected, it has excellent storage properties and is easy to use. Further, if the adhesive composition is applied to the release substrate and dried, and then, if necessary, another release substrate is attached, so that the adhesive layer itself can be transferred to another substrate.

<Release substrate>
The release substrate is not particularly limited, but, for example, high-quality paper, kraft paper, roll paper, on both sides of paper such as glassine paper, clay, polyethylene, a coating layer of a filler such as polypropylene, etc. And a silicone-based, fluorine-based, or alkyd-based release agent applied on each of the coating layers. In addition, various olefin films such as polyethylene, polypropylene, ethylene-α-olefin copolymer, and propylene-α-olefin copolymer alone, and those obtained by applying the release agent on a film such as polyethylene terephthalate may also be used. The release force between the release base material and the adhesive layer, the use of alkyd-based release agents on both sides of high-quality paper, and polypropylene, for the reason that silicone has an adverse effect on electrical properties, Alternatively, it is preferable to use an alkyd release agent on polyethylene terephthalate.

  In the present embodiment, the method for coating the adhesive composition on the substrate is not particularly limited, and examples thereof include a comma coater and a reverse roll coater. Alternatively, if necessary, an adhesive layer can be provided directly or by a transfer method on a rolled copper foil or a polyimide film which is a constituent material of a printed wiring board. The thickness of the adhesive layer after drying is appropriately changed as necessary, but is preferably in the range of 5 to 200 μm. If the thickness of the adhesive layer is less than 5 μm, the adhesive strength may be insufficient. When the thickness is 200 μm or more, drying may be insufficient and the residual solvent may increase, and there is a problem that blisters may be generated at the time of pressing for manufacturing a printed wiring board. The drying conditions are not particularly limited, but the residual solvent ratio after drying is preferably 1% by mass or less. If it exceeds 1% by mass, there is a problem in that the residual solvent foams during pressing in the production of a printed wiring board and blisters are likely to occur.

<Printed wiring board>
The printed wiring board according to the present embodiment includes, as constituent elements, a laminate formed from a metal foil forming a conductive circuit and a resin base material. The printed wiring board can be manufactured by a conventionally known method such as a subtractive method using a metal-clad laminate. The printed wiring board according to the present embodiment is a so-called flexible circuit board (FPC) in which a conductor circuit formed of a metal foil is partially or entirely covered with a cover film or screen printing ink as necessary. , Flat cables, circuit boards for tape automated bonding (TAB), and the like.

  The printed wiring board of the present embodiment can have any laminated configuration that can be adopted as a printed wiring board. For example, it can be a printed wiring board composed of four layers of a base film layer, a metal foil layer, an adhesive layer, and a cover film layer. Further, for example, a printed wiring board composed of five layers of a base film layer, an adhesive layer, a metal foil layer, an adhesive layer, and a cover film layer can be provided.

  Furthermore, if necessary, a configuration in which two or three or more of the above-described printed wiring boards are stacked may be employed.

  The adhesive composition of the present embodiment can be suitably used for each adhesive layer of a printed wiring board. In particular, when the adhesive composition of the present embodiment is used as an adhesive, the adhesive composition has high adhesiveness not only to a conventional polyimide, polyester film, and copper foil constituting a printed wiring board but also to a low-polarity resin base material such as LCP. In addition, solder reflow resistance can be obtained, and the adhesive layer itself has excellent low dielectric properties. Therefore, it is suitable as an adhesive composition used for coverlay films, laminates, copper foil with resin, and bonding sheets.

  In the printed wiring board of the present embodiment, as the base film, any resin film conventionally used as a base material of the printed wiring board can be used. Examples of the resin of the base film include polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, and fluorine resin. The adhesive composition of the present embodiment has excellent adhesion even to a low-polar substrate such as a liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, or a polyolefin resin.

<Cover film>
As the cover film, any conventionally known insulating film as an insulating film for a printed wiring board can be used. For example, manufactured from various polymers such as polyimide, polyester, polyphenylene sulfide, polyether sulfone, polyether ether ketone, aramid, polycarbonate, polyarylate, polyimide, polyamide imide, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, and polyolefin resin. The film to be used is usable. More preferably, it is a polyimide film or a liquid crystal polymer film.

  Hereinafter, the present invention will be described more specifically based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Physical property evaluation method]
<Weight average molecular weight (Mw)>
The weight average molecular weight (Mw) was measured by GPC (gel permeation chromatography). A column prepared by dissolving a maleimide resin in tetrahydrofuran (THF) at a concentration of 3% by mass was heated to 30 ° C. (GL-R420 (manufactured by Hitachi High-Tech Fielding Co., Ltd.) × 1, GL-R430 ( 50 μL was injected into 1 × GL-R440 (manufactured by Hitachi High-Tech Fielding Co., Ltd.) and 1 × GL-R440 (manufactured by Hitachi High-Tech Fielding Co., Ltd.), and measurement was carried out at 1.6 mL / min using THF as a developing solvent. Was. In addition, an L-3350 RI detector (manufactured by Hitachi, Ltd.) was used as a detector, and a weight average molecular weight (Mw) was obtained from a molecular weight / elution time curve prepared using standard polystyrene (manufactured by Tosoh Corporation) based on the elution time. ) Was converted.

<Compatibility>
Compatibility refers to a composition obtained by blending (A) a bismaleimide resin, (B) an epoxy resin, (C) a curing agent, and (D) an organic solvent and stirring the mixture under the conditions of Example 1 described below. Refers to the state observed. If the compatibility is good, it means that there is no precipitate, etc., and it can be applied to the substrate.If the compatibility is poor, there is a precipitate, etc., which makes it difficult to apply it to the substrate. Point to.
(Evaluation criteria)
○: No precipitate ×: Precipitate

<Preparation of resin film>
The adhesive composition obtained in Examples and Comparative Examples described below is dried on a Purex (registered trademark) A31 (polyester film, manufactured by Teijin Dupont Co., Ltd., trade name) using an applicator. Was applied so as to have a thickness of 65 μm, and dried at 130 ° C. for 10 minutes using an oven to produce a resin film.

<Adhesive strength>
A resin film from which Purex A31 has been peeled off, a glass plate having a thickness of 0.7 mm, and an LCP film having a thickness of 75 μm (trade name “Vexter” manufactured by Kuraray Co., Ltd.) laminated with the resin film in the middle Then, thermocompression bonding was performed at 200 ° C. and 2 MPa for 1 hour using a hot press to obtain a laminate in which a glass plate, a cured resin film, and an LCP film were laminated in this order. The adhesive strength was measured by peeling off the LCP film of the obtained laminate. The peel strength was measured at a room temperature at a tensile speed of 5 mm / s using a 90 ° peeling measuring device (trade name “RHEONER II CREEMETER RE2-3305B” manufactured by Yamaden Corporation). Further, a peeling position (peeling mode) at the time of peeling was observed. The peeling mode means that “substrate destruction” has higher adhesive strength than “interfacial peeling”.

<Dielectric constant and dissipation factor>
The resin film from which Purex A31 was peeled off and two copper foils (trade name “F2WS-18”, manufactured by Furukawa Electric Co., Ltd.) were laminated so that the roughened surface of the copper foil faced the resin film, Thermocompression bonding was performed by a hot press at 200 ° C. and 2 MPa for 1 hour to obtain a copper foil laminate in which a copper foil, a cured resin film, and a copper foil were laminated in this order. The copper foil on both sides of the obtained copper foil laminate was removed by etching, dried at 130 ° C. for 30 minutes, and then a 5 cm × 5 cm test piece was prepared, and a dielectric constant measuring device (manufactured by Agilent Technologies, product) Under the name “E4980A Precision LCR Meter”), the dielectric constant and the dielectric loss tangent at a frequency of 1 MHz were measured.

[Synthesis of bismaleimide resin]
<Synthesis example 1>
60.8 parts by mass of pyromellitic dianhydride (manufactured by Daicel Co., Ltd.) and mesitylene (manufactured by Toyo Gosei Kogyo Co., Ltd.) were placed in a 1 L flask container equipped with a condenser, a nitrogen inlet tube, a thermocouple, and a stirrer. 4 parts by mass and 90.7 parts by mass of ethanol (manufactured by Wako Pure Chemical Industries, Ltd.) were added. After the introduction, the temperature was raised to 80 ° C., and the temperature was maintained for 0.5 hour, and 201.3 parts by mass of dimer diamine (trade name “PRIAMINE 1075”, manufactured by Croda Japan Ltd.) was added dropwise. After the dropwise addition, 4.3 parts by mass of methanesulfonic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was added. Thereafter, the temperature was raised to 165 ° C., and a dehydration ring-closing reaction was performed at 165 ° C. for 1 hour to remove water and ethanol in the reaction solution to obtain an intermediate polyimide resin. Subsequently, the obtained polyimide resin was cooled to 80 ° C., 27.3 parts by mass of maleic anhydride (manufactured by Fuso Chemical Industry Co., Ltd.) was added, the temperature was raised to 160 ° C., and a dehydration ring closure reaction was performed at 160 ° C. for 2 hours. Then, water in the reaction solution was removed to obtain a bismaleimide resin.

  The obtained bismaleimide resin was put into a separating funnel, 1000 parts by mass of pure water was charged, and the separating funnel was shaken and allowed to stand. After standing, the aqueous layer and the organic layer were separated, and then only the organic layer was recovered. The collected organic layer is poured into a 1-L glass container equipped with a cooler, a nitrogen inlet tube, a thermocouple, a stirrer, and a vacuum pump, and the temperature is raised to 88 to 93 ° C. The temperature was raised, and the solvent was removed for 1 hour in a state where the pressure was reduced from the atmospheric pressure by 0.1 MPa to obtain a bismaleimide resin (A-1) (weight average molecular weight of 16,000) as the component (A).

<Synthesis Example 2>
The component (A) was prepared in the same manner as in Synthesis Example 1 except that 86.4 parts by mass of 4,4′-oxydiphthalic anhydride was used instead of pyromellitic dianhydride as the tetracarboxylic dianhydride. (B-2) (weight average molecular weight 17000) was obtained.

[Example 1]
In a 500 ml four-necked flask equipped with a stirrer, 85 parts by mass of the maleimide resin (A-1) obtained in Synthesis Example 1 and an epoxy resin (trade name “jER-825”, manufactured by Mitsubishi Chemical Corporation) were added. 15 parts by mass and 100 parts by mass of toluene were charged and stirred for 3 hours. To the obtained solution, 2 parts by mass of a curing agent (trade name “TBP-3S”, manufactured by Hokuko Chemical Co., Ltd.) was added, and the mixture was further stirred for 0.5 hour to obtain an adhesive composition. Table 1 shows the compounding amounts of the respective components and the physical property evaluation results. In Table 1, the amounts of the components (A) to (D) indicate parts by mass.

[Examples 2 to 12, Comparative Examples 1 to 10]
Bonding of Examples 2 to 12 and Comparative Examples 1 to 10 in the same manner as in Example 1 except that the type and the amount of the bismaleimide resin or the epoxy resin were changed to the contents shown in Tables 1 and 2. Agent composition was obtained. Tables 1 and 2 show the amounts of each component and the results of evaluation of the physical properties. In Tables 1 and 2, the amounts of the components (A) to (D) indicate parts by mass. Details of the components (A) to (D) are as follows.

Component (A): Bismaleimide resin (A-1) Bismaleimide resin of Synthesis Example 1 (weight average molecular weight 16,000)
(A-2) Bismaleimide resin of Synthesis Example 2 (weight average molecular weight 17000)

(B) component: epoxy resin (B-1) bisphenol A type epoxy resin: jER-825 (manufactured by Mitsubishi Chemical Corporation)
(B-2) Bisphenol F type epoxy resin: YDF-8170C (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
(B-3) Naphthalene skeleton modified novolak type epoxy resin: HP-5000 (manufactured by DIC Corporation)
(B-4) Bisphenol-type flexible epoxy resin: EXA-4850-150 (manufactured by DIC Corporation)
(B-5) Biphenyl novolak epoxy resin: NC-3000H (manufactured by Nippon Kayaku Co., Ltd.)
(B-6) Cresol novolak type epoxy resin: N-670 (manufactured by DIC Corporation)
(B-7) 4,4′-methylenebis (N, N-diglycidylaniline) (manufactured by Tokyo Chemical Industry Co., Ltd.) (hereinafter abbreviated as “MBDGA”)
(B-8) Dicyclopentadiene type epoxy resin: HP-7200HHH (manufactured by DIC Corporation)
(B-9) Triphenolmethane type epoxy resin: HPPN-501H (manufactured by Nippon Kayaku Co., Ltd.)

Component (C): curing agent (C-1) tetrabutylphosphonium-1,2-cyclohexyldicarboxylic acid (cation type: anion type = 1: 1): TBP-3S (manufactured by Hokuko Chemical Co., Ltd.)

  In Tables 1 and 2, the adhesive strength “> 2.0 kN / m” indicates the measurement limit of the device. However, even those having an adhesive strength of “> 2.0 kN / m” were at least partially peeled off by pulling by hand or the like, and the breaking mode at that time was evaluated.

  As is clear from the results shown in Tables 1 and 2, the adhesive composition (Example) containing a specific bismaleimide resin of the present invention, a specific and predetermined amount of an epoxy resin, and a curing agent was prepared by using LCP. And high adhesive strength. In particular, when the content of the component (B) having a specific structure is 15 parts by mass or more and 35 parts by mass or less when the total amount of the components (A) and (B) is 100 parts by mass (Example), this content is included. It was confirmed that the adhesive strength can be significantly improved as compared with the case where the amount is less than 15 parts by mass or exceeds 35 parts by mass (Comparative Examples 1 to 7). Furthermore, it was confirmed that the adhesive composition (Example) of the present invention had a low dielectric constant and a low dielectric loss tangent, and was excellent in low dielectric properties.

ADVANTAGE OF THE INVENTION The adhesive composition which has high adhesiveness with the low polar resin base material, such as LCP which has the low dielectric property superior to the conventional polyimide by this invention, and is further excellent in a low dielectric property, The laminated body which adhered using this And an adhesive sheet. Due to the above properties, the adhesive composition of the present invention is useful in flexible printed wiring board applications, particularly in FPC applications requiring low dielectric properties (low dielectric constant and low dielectric loss tangent) in a high frequency range.

Claims (7)

(A) a bismaleimide resin represented by the following general formula (1), (B) an epoxy resin, and (C) a curing agent,
(B) the epoxy resin contains at least one epoxy resin selected from the group consisting of an epoxy resin having a bisphenol A skeleton, an epoxy resin having a bisphenol F skeleton, and a polyfunctional epoxy resin having a novolak skeleton.
The adhesive composition, wherein the content of the component (B) is 15 to 35 parts by mass with the total amount of the components (A) and (B) being 100 parts by mass.

[In the formula (1), R ¹ represents a divalent hydrocarbon group derived from dimer acid, Q represents a substituted or unsubstituted aliphatic group having 1 to 100 carbon atoms, a substituted or unsubstituted aromatic group, Alternatively, it represents a substituted or unsubstituted heteroaromatic group, and n represents an integer of 0 to 100. ]   The adhesive composition according to claim 1, wherein the component (C) contains at least one selected from the group consisting of a phosphine compound, a phosphonium salt compound, and an imidazole compound.   The adhesive according to claim 1, wherein the content of the component (C) is 0.1 to 5.0 parts by mass based on 100 parts by mass of the total of the components (A) and (B). Composition.   The adhesive composition according to any one of claims 1 to 3, which is used for bonding a resin substrate and a resin substrate or a metal substrate.   A laminate comprising: a base material; and an adhesive layer formed on the base material using the adhesive composition according to claim 1.   A laminate comprising a resin substrate and a resin or metal substrate bonded by the adhesive composition according to claim 1. An adhesive sheet comprising the laminate according to claim 5.