WO2020012978A1

WO2020012978A1 - Adhesive composition, laminate, and adhesive sheet

Info

Publication number: WO2020012978A1
Application number: PCT/JP2019/025722
Authority: WO
Inventors: 来佐藤; 武史中村; 正嗣水野; 誌朗正木
Original assignee: 日立化成株式会社; 日立化成テクノサービス株式会社
Priority date: 2018-07-13
Filing date: 2019-06-27
Publication date: 2020-01-16
Also published as: TW202012582A; JPWO2020012978A1

Abstract

An adhesive composition containing (A) a bismaleimide resin represented by general formula (1), (B) an epoxy resin represented by general formula (2), and (C) a curing accelerator. [In formula (1), R1 represents 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.] [In formula (2), R2 represents a hydrogen atom or a methyl group, and m represents an integer of 0-30.]

Description

Adhesive composition, laminate and adhesive sheet

The present disclosure relates to an adhesive composition, a laminate, and an adhesive sheet. More specifically, the present disclosure 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 is 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 base 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. Thus, 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 that, although they can obtain adhesiveness with a polyimide film, they cannot easily 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.

In the case where an LCP base material is used, there is a method in which the LCP is melted without using an adhesive and 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 easily formed at the time of processing, and the yield is reduced.

The present disclosure has been made in view of the problems of the above prior art, and has an adhesive composition having good adhesion 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 to solve the above-described problems, and contain a specific bismaleimide resin having a structure derived from dimer acid, and an epoxy resin having a further specific structure, and a curing accelerator. The present inventors have found that an adhesive composition containing the compound exhibits excellent low dielectric properties and has high adhesiveness to a resin substrate having low dielectric properties such as LCP, and has completed the present invention.

That is, the present disclosure provides the following inventions.
[1] Adhesion containing (A) a bismaleimide resin represented by the following general formula (1), (B) an epoxy resin represented by the following general formula (2), and (C) a curing accelerator. Composition.

[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. ]

[In the formula (2), R ² represents a hydrogen atom or a methyl group, and n represents an integer of 0 to 30. ]
[2] The adhesive composition according to [1], wherein the component (C) contains at least one selected from the group consisting of a phosphine compound, a phosphonium salt compound, an imidazole compound, and an amine compound.
[3] The above-mentioned [1] or [2], wherein the content of the component (B) is 10 to 40 parts by mass based on 100 parts by mass of the total of the components (A) and (B). Adhesive composition.
[4] The above-mentioned [1] to [3], 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 according to any one of the above.
[5] The adhesive composition according to any one of [1] to [4], which is used for bonding a resin substrate to a resin substrate or a metal substrate.
[6] 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 [5].
[7] A laminate comprising a resin substrate and a resin or metal substrate bonded by the adhesive composition according to any one of the above [1] to [5].
[8] An adhesive sheet comprising the laminate according to [6] or [7].

According to the present disclosure, it is possible to provide an adhesive composition having good adhesion to a substrate such as LCP and also having excellent low dielectric properties, and a laminate and an adhesive sheet using the same.

Hereinafter, the present disclosure will be described in detail in accordance with 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 “component (A)”) and (B) a general formula (2). (Hereinafter, also referred to as “component (B)”) and (C) a curing accelerator (hereinafter, also referred to as “component (C)”). 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.

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 base material 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 adhesiveness to a resin substrate having low dielectric properties such as LCP and obtaining better low dielectric properties. Is preferred.

@Dimer diamine is a compound derived from dimer acid, which is a dimer of unsaturated fatty acids such as oleic acid, as described in, for example, JP-A-9-112712. 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, and are integers of 1 to 12 There may be. In the formulas (3) and (4), the bond shown 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 formula (4) are preferred, and compounds represented by the following formula (4-1) are particularly preferred.

市販 Examples of commercially available dimer diamines include 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'-oxydiphthalic acid 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. Above all, 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 3000 to 70000 from the viewpoint of obtaining better adhesiveness to a resin base material having low dielectric properties such as LCP and obtaining better low dielectric properties. It is more preferably from 5,000 to 50,000, even more preferably from 7000 to 30,000.

(A) Bismaleimide resin may be a commercially available compound. Specifically, for example, DESIGNERＤＥMOLECURES Inc. BMI-3000 (synthesized from dimer diamine, pyromellitic dianhydride and maleic anhydride), BMI-1500, BMI-1700, BMI-5000 and the like can be preferably used.

<(B) component: epoxy resin>
(B) The epoxy resin is not particularly limited as long as it is represented by the following general formula (2), and examples thereof include a bisphenol A epoxy resin and a bisphenol F epoxy resin. These can be used alone or in combination of two or more. As the epoxy resin (B), it is preferable to use a liquid bisphenol A epoxy resin or a liquid bisphenol F epoxy resin from the viewpoint of compatibility with the (A) bismaleimide resin.

In the formula (2), R ² represents a hydrogen atom or a methyl group, and m represents an integer of 0 to 30. M in the formula (2) is preferably an integer of 0 to 10 from the viewpoint of obtaining better adhesiveness to a resin base material having low dielectric properties such as LCP and obtaining better low dielectric properties. .

The content of the epoxy resin (B) is preferably from 10 to 40 parts by mass, more preferably from 10 to 30 parts by mass, where the total amount of the components (A) and (B) is 100 parts by mass. , More preferably from 12 to 25 parts by mass, particularly preferably from 15 to 20 parts by mass. When the content of the component (B) is 10 parts by mass or more, excellent adhesive strength to the LCP substrate tends to be easily obtained. When the content is 40 parts by mass or less, more excellent low dielectric properties are obtained. Tend to be more likely to be caught.

<(C) component: curing accelerator>
(C) The curing accelerator is not particularly limited, and examples thereof include a phosphine compound, a phosphonium salt compound, an imidazole compound, and an amine 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 phosphine; dialkyl phosphines such as dimethyl phosphine and diethyl phosphine; diphenyl phosphine such as diphenyl phosphine; methyl phenyl phosphine; Graded phosphines; trialkyl phosphines such as trimethyl phosphine, triethyl phosphine, tributyl phosphine, trioctyl phosphine, tricyclohexyl phosphine, triphenyl phosphine, alkyl diphenyl phosphine, dialkyl phenyl phosphine, tribenzyl phosphine, tolyl phosphine, tri-p- Styrylphosphine, tris (2,6-dimethoxyphenyl) phosphine, tri-4- Chill 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 1- (2-cyanoethyl) -2-phenylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-ethylimidazole, and 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-cyano Chill-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecyl imidazole, 1-cyanoethyl-2-phenylimidazole, and the like. Among them, imidazole compounds include 1- (2-cyanoethyl) -2-phenylimidazole, 1,2-dimethylimidazole, 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, and 2-ethyl-imidazole. 4-Methylimidazole is preferred. By using these compounds, the reaction of the (A) bismaleimide resin is further promoted, and higher adhesiveness to a resin substrate having low dielectric properties such as LCP is easily obtained.

Examples of the amine compound include triethylamine, dimethylbenzylamine, triethylenediamine, tripropylamine, tributylamine, dimethylethanolamine, triethanolamine, 4-aminopyridine, 2-aminopyridine, N, N-dimethyl-4-amino Examples include pyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine and the like.

(C) The content of the curing accelerator 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 of the component (A) is used. The total amount is preferably 0.1 to 5.0 parts by mass, more preferably 1.0 to 3.0 parts by mass, based on 100 parts by mass of the total 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 accelerator. (D) Specific examples of the organic solvent include 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.

接着 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 colorant, a coupling, Agents and the like may be blended within a range that does not impair the effects of the present disclosure.

<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 and stearic acid amide, which are ester compounds with the above, 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 (a two-layer laminate of a substrate / adhesive layer) or 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 adhesive composition of the present embodiment can be applied to various substrates and dried according to a conventional method, and further laminated with another substrate to obtain the laminate of the present embodiment.

<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.

材質 Examples of the material of the resin base material 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”).

As the metal substrate, any conventionally known conductive material that can be used for a circuit board can be used. 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 be reduced. 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 preferred.

<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 mold, laminate (substrate / adhesive layer / substrate) / adhesive layer / release mold, or release Base material / adhesive layer / laminated body (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. Further, 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. Also, 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 excellent operability is achieved, 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 if necessary, another release substrate is attached, the adhesive layer itself can be transferred to another substrate.

<Release substrate>
The release substrate is not particularly limited, for example, a 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 polyethylene and polypropylene. 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 above release agent on a film such as polyethylene terephthalate may also be used. The release force between the release substrate 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 adversely affects the 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. If 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 that the residual solvent foams during the press for producing a printed wiring board, and blisters are easily generated.

<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 conductive 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.

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

{Circle around (2)} If necessary, two or three or more of the above printed wiring boards may be laminated.

接着 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 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 a coverlay film, a laminate, a copper foil with resin, and a bonding sheet.

プリント 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-based resin, and fluorine-based resin. The adhesive composition of the present embodiment has excellent adhesiveness even to a low-polar substrate such as a liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, and 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 disclosure will be described more specifically based on examples and comparative examples, but the present disclosure 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 bismaleimide 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). Inject 50 μL into (× 1 bottle of Hitachi High-Tech Fielding Co., Ltd.) and 1 × GL-R440 (× 1 bottle of Hitachi High-Tech Fielding Co., Ltd.), measure at 1.6 mL / min flow rate using THF as a developing solvent. went. In addition, an L-3350 RI detector (manufactured by Hitachi, Ltd.) was used as the 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>
The compatibility refers to a composition obtained by mixing (A) a bismaleimide resin, (B) an epoxy resin, (C) a curing accelerator, and (D) an organic solvent, and stirring the mixture under the conditions of Example 1 described below. Refers to the state observed visually. 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. For those having poor compatibility, other physical properties were not evaluated because it was difficult to form a film.
(Evaluation criteria)
○: No precipitate (transparent)
△: No precipitate (turbidity)
×: with precipitate

<Preparation of resin film>
The adhesive composition obtained in Examples and Comparative Examples described below was dried on a Purex (registered trademark) A31 (polyester film, manufactured by Teijin Dupont Co., Ltd., trade name) using an applicator. Was applied to 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 was 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 with a hot press at 200 ° C. and 2 MPa for 1 hour 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 the LCP film of the obtained laminate. The peeling strength was measured at a normal 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 dielectric loss tangent>
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 test piece of 5 cm × 5 cm was prepared. The dielectric constant and the dielectric loss tangent at a frequency of 1 MHz were measured under the name "E4980A Precision LCR Meter").

[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 Crowda Japan Co., 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.

(4) 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, heated to 88 to 93 ° C., and water is removed. The temperature was raised and the solvent was removed for 1 hour under reduced pressure of 0.1 MPa from atmospheric pressure to obtain a bismaleimide resin (A-1) (weight average molecular weight of 16,000) as the component (A).

<Synthesis Example 2>
Component (A) was prepared in the same manner as in Synthesis Example 1, except that 8,4 parts by mass of 4,4′-oxydiphthalic anhydride was used instead of pyromellitic dianhydride as the tetracarboxylic dianhydride. Was obtained (weight average molecular weight 17000).

[Example 1]
In a 500 ml four-necked flask equipped with a stirrer, 90 parts by mass of the bismaleimide resin (A-1) obtained in Synthesis Example 1 and an epoxy resin (trade name “jER-825”, manufactured by Mitsubishi Chemical Corporation) And 100 parts by mass of toluene, and stirred for 3 hours. To the obtained solution, 2 parts by mass of a curing accelerator (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 amounts of the components and the results of evaluation of the physical properties. In Table 1, the amounts of the components (A) to (D) indicate parts by mass.

[Examples 2 to 12, Comparative Examples 1 to 13]
Examples 2 to 12 and Comparative Examples 1 to 12 were performed in the same manner as in Example 1 except that the kind and the amount of the bismaleimide resin, the epoxy resin, or the curing accelerator were changed to the contents shown in Table 1 or Table 2. Thus, 13 adhesive compositions were obtained. Tables 1 and 2 show the amounts of the components and the results of the physical property evaluation. 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. In the component (B), (B-1) to (B-2) are epoxy resins satisfying the general formula (2), and (B-3) to (B-13) do not satisfy the general formula (2). Epoxy resin.

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)

Component (B): 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) 4,4′-methylenebis (N, N-diglycidylaniline) (manufactured by Tokyo Chemical Industry Co., Ltd.) (hereinafter abbreviated as “MBDGA”)
(B-4) Naphthalene skeleton modified polyfunctional epoxy resin: HP-5000 (manufactured by DIC Corporation)
(B-5) Naphthalene type epoxy resin: HP-6000 (manufactured by DIC Corporation)
(B-6) Cresol novolak type epoxy resin: N-670 (manufactured by DIC Corporation)
(B-7) Biphenyl novolak epoxy resin: NC-3000H (manufactured by Nippon Kayaku Co., Ltd.)
(B-8) Bisphenol-type flexible epoxy resin: EXA-4850-150 (manufactured by DIC Corporation)
(B-9) Naphthalene type epoxy resin: HP-4710 (manufactured by DIC Corporation)
(B-10) Naphthalene type epoxy resin: NC-7000L (manufactured by Nippon Kayaku Co., Ltd.)
(B-11) Bisphenol S type epoxy resin: EXA-1514 (manufactured by DIC Corporation) (B-12) o-cresol novolak type epoxy resin: YDCN-700-10 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
(B-13) Triphenolmethane epoxy resin: HPPN-501H (manufactured by Nippon Kayaku Co., Ltd.)

Component (C): curing accelerator (C-1) tetrabutylphosphonium-1,2-cyclohexyldicarboxylic acid (cation type: anion type = 1: 1): TBP-3S (manufactured by Hokuko Chemical Co., Ltd.)
(C-2) 1- (2-cyanoethyl) -2-phenylimidazole: 2PZCN (manufactured by Shikoku Chemicals Co., Ltd.)
(C-3) 1,2-dimethylimidazole: 1,2-DMZ (manufactured by Shikoku Chemicals Co., Ltd.)
(C-4) Dimethylbenzylamine: DMBA (Fuji Film Wako Pure Chemical Industries, Ltd.)

において 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 the bismaleimide resin, the epoxy resin, and the curing accelerator of the present disclosure shows high adhesive strength with LCP. Was confirmed. Furthermore, it was confirmed that the adhesive composition (Example) of the present disclosure has low dielectric constant and dielectric loss tangent, and is excellent in low dielectric properties.

で In the present disclosure, it is believed that the mechanism by which the adhesive composition exhibited high adhesive strength with LCP is related to the compatibility between the bismaleimide resin and the epoxy resin. When the compatibility between the bismaleimide resin and the epoxy resin is good, the maleimide group and the epoxy group are uniformly copolymerized, and the hydroxy group is dispersed, so that the LCP and the hydroxy group can interact with each other to exhibit high adhesive strength. thinking. On the other hand, if the compatibility between the bismaleimide resin and the epoxy resin is poor, the bismaleimide resin and the epoxy resin react with each other, causing microphase separation, and the hydroxy groups do not disperse and interact with each other. It is thought that the adhesive strength will be low because of the inability to interact with.

According to the present disclosure, an adhesive composition having high adhesiveness to a low-polar resin base material such as LCP having low dielectric properties superior to conventional polyimide, and further excellent in low dielectric properties, and a laminate bonded using the same And an adhesive sheet. Due to the above characteristics, the adhesive composition of the present disclosure is useful in flexible printed wiring board applications, particularly in FPC applications that require low dielectric properties (low dielectric constant and low dielectric loss tangent) in a high frequency range.

Claims

(A) An adhesive composition containing a bismaleimide resin represented by the following general formula (1), (B) an epoxy resin represented by the following general formula (2), and (C) a curing accelerator. .

[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. ]

[In the formula (2), R 2 represents a hydrogen atom or a methyl group, and m represents an integer of 0 to 30. ]
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, an imidazole compound, and an amine compound.
(3) The adhesive composition according to (1) or (2), wherein the content of the component (B) is 10 to 40 parts by mass based on 100 parts by mass of the total of the components (A) and (B).
The content according to any one of claims 1 to 3, 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 according to item 1.
(5) The adhesive composition according to any one of (1) to (4), 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 any one of claims 1 to 5.
A laminate comprising a resin substrate and a resin or metal substrate bonded by the adhesive composition according to any one of claims 1 to 5.
接着 An adhesive sheet comprising the laminate according to claim 6.