JP2008111102A - Flame-retardant adhesive composition, and adhesive sheet, cover-lay film and flexible copper-clad laminate using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonhalogen flame-retardant adhesive composition having excellent migration resistance not only in a single layer plate structure but also in a copper-clad plate having a densified multilayer structure and the like. <P>SOLUTION: The flame retardant adhesive composition comprises (A) a nonhalogen epoxy resin, (B) a carboxy-containing acrylic resin and/or a carboxy-containing acrylonitrile-butadiene rubber, (C) a curing agent, (E) a specific phosphinic acid-based compound and (F) an ion scavenger and/or a heavy metal-inactivating agent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an adhesive composition in which a cured product obtained by curing is excellent in flame retardancy and migration resistance and does not contain a halogen, and an adhesive sheet, a coverlay film and a flexible copper-clad using the composition The present invention relates to a laminated board.

  In recent years, the development of the electronics field has been remarkable, and in particular, electronic devices for communication and consumer use have been reduced in size, weight and density, and the demand for these performances has become increasingly sophisticated. In response to such demands, flexible printed wiring boards are flexible and can withstand repeated bending, so they can be three-dimensionally mounted in a narrow space. Wiring to electronic devices, cables and connectors Applications are expanding as composite parts with functions.

  The flexible printed wiring board is obtained by preparing a circuit on a flexible printed wiring board by a conventional method and attaching a coverlay film in a form that protects the circuit depending on the purpose of use. The flexible printed wiring board used in this flexible printed wiring board is a laminate of an electrically insulating film having high heat resistance and excellent electrical and mechanical properties and a metal foil laminated with an adhesive. Properties required for the flexible printed wiring board include adhesion durability, heat resistance, flexibility, folding resistance, migration resistance, flame resistance, and the like. In addition, the adhesive sheet is a sheet used to form a multilayer structure by laminating two or more single-sided copper foils or double-sided copper foil flexible printed wiring boards, or a reinforcing plate or the like is bonded to the flexible printed wiring board. Therefore, the properties required for the adhesive sheet include adhesive strength, heat resistance, migration resistance, and the like.

  Against the background of environmental problems in recent years, there is a tendency to suppress the use of halogen compounds in components mounted on electronic devices. Conventionally, bromine compounds that have been frequently used to make flexible printed wiring board materials flame-retardant It has become difficult to use.

  Due to the above-described background, recently, a technique for making a flame retardant by adding a phosphorus compound instead of a bromine compound as a flame retardant to an adhesive has been taken. For example, a resin composition (Patent Document 1 and Patent Document 2) mainly composed of an epoxy resin, a phosphate ester compound, a phenolic curing agent, and NBR rubber has been proposed. However, since the phosphate ester is inferior in heat and moisture resistance, the phosphate ester is hydrolyzed under high-temperature and high-humidity conditions to produce an ionic component, and the substrate has insufficient migration resistance, peeling properties and solvent resistance. . Further, an adhesive composition (Patent Document 3 and Patent Document 4) containing a phosphazene compound, a polyepoxy compound, a curing agent, a curing accelerator, a synthetic rubber, and an inorganic filler has been proposed. It was difficult to sufficiently satisfy the peeling characteristics, solvent resistance and solder heat resistance.

  Furthermore, according to the study by the present inventors, even if the single-layer board structure that has been widely used in the past has excellent migration resistance, when the flexible printed wiring board is multi-layered and densified, other thermal loads (heat It has been found that when the (history) is repeatedly applied, the migration resistance may be insufficient, and further improvement of the migration resistance is necessary.

JP 2001-339131 A JP 2001-339132 A JP 2001-19930 A JP 2002-60720 A

  Therefore, the present invention is non-halogen, excellent in flame retardancy, adhesion, and heat resistance, and not only excellent in migration resistance in a conventionally used single layer plate structure, but also in a higher density multilayer plate. It is an object of the present invention to provide an adhesive composition excellent in migration resistance even in the structure, and a printed board material such as an adhesive sheet, a coverlay film, and a copper clad laminate using the composition.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors use a specific phosphinate compound as a flame retardant component, and an ion scavenger and / or heavy metal deactivator as an essential component. As a result, it has been found that the above-mentioned problems can be solved.

That is, the present invention
(A) non-halogen epoxy resin,
(B) a carboxyl group-containing acrylic resin and / or a carboxyl group-containing acrylonitrile-butadiene rubber,
(C) a curing agent,
(E) Phosphinic acid salt represented by the following general formula (1) and / or diphosphinic acid salt represented by the following general formula (2)

（１）

(1)

Wherein R ₁ and R ₂ may be the same or different and are monovalent linear or branched alkyl groups having 1 to 6 carbon atoms, or preferably aryl groups having 6 carbon atoms, M Is selected from the group consisting of Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, and a protonated nitrogen base M is an integer of 1 to 4.)

（２）

(2)

(Wherein R ₁ , R ₂ , M and m are as defined above, R ₃ is a divalent linear or branched alkylene group having 1 to 10 carbon atoms and arylene having 6 to 10 carbon atoms) A group, an alkylarylene group having 6 to 10 carbon atoms, or an arylalkylene group having 6 to 10 carbon atoms, n is an integer of 1 to 4, and x is an integer of 1 to 4, provided that 2n = mx)), and

(F) A flame retardant adhesive composition comprising an ion scavenger and / or a heavy metal deactivator is provided.

  Moreover, this invention provides the adhesive sheet which has a mold release base material and the layer which consists of the said adhesive composition formed in the single side | surface of this base material. The adhesive sheet is obtained by applying the adhesive composition to a substrate having releasability.

  Furthermore, this invention provides the coverlay film which has an insulating film and the layer which consists of the said composition provided in the at least single side | surface of this insulating film. The cover lay film is obtained by applying the composition onto an insulating film.

  Furthermore, the present invention provides an electrically insulating film, a layer made of the above-mentioned adhesive composition provided on one or both sides of the insulating film, and a single-layer or double-layer adhesive composition layer thus provided. Provided is a flexible copper clad laminate having one or two layers of copper foil provided. The flexible copper-clad laminate is obtained by bonding an electrically insulating film and a copper foil with the adhesive composition.

  In the composition of the present invention, a cured product obtained by curing is excellent in flame retardancy, adhesion, and heat resistance, is further excellent in migration resistance than before, and does not contain a halogen. Therefore, the adhesive sheet, coverlay film and flexible copper clad laminate produced using this composition are also excellent in flame retardancy, adhesion and heat resistance, and a thermal load (heat history) is repeatedly applied. Even in a multilayer board (laminated) structure, it has excellent migration resistance.

<Flame-retardant adhesive composition>
Hereinafter, the constituent components of the flame retardant adhesive composition of the present invention will be described in more detail.

[(A) Non-halogen epoxy resin]
The non-halogen epoxy resin as component (A) is an epoxy resin that does not contain a halogen atom such as bromine in its molecule. This epoxy resin is not specifically limited, For example, you may contain silicone, urethane, a polyimide, polyamide, etc. Further, the skeleton may contain a phosphorus atom, a sulfur atom, a nitrogen atom or the like.

  Examples of such epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, or hydrogenated products thereof, phenol novolac type epoxy resins, cresol novolac type epoxy resins and other glycidyl ether type epoxy resins, Glycidyl ester epoxy resins such as glycidyl hexahydrophthalate and dimer acid glycidyl esters, glycidyl amine epoxy resins such as triglycidyl isocyanurate and tetraglycidyl diaminodiphenylmethane, linear aliphatics such as epoxidized polybutadiene and epoxidized soybean oil Epoxy resin, etc., preferably bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novo Click type epoxy resins. As these commercially available products, for example, Epicoat 828 (manufactured by Japan Epoxy Resin), Epicron 830S (manufactured by Dainippon Ink and Chemicals), Epicoat 517 (manufactured by Japan Epoxy Resin), EOCN103S (manufactured by Nippon Kayaku), etc. Is mentioned.

  In addition, various phosphorus-containing epoxy resins in which phosphorus atoms are bonded using a reactive phosphorus compound are also effectively used when constituting a flame-retardant adhesive composition that does not contain a halogen. Specifically, for example, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (manufactured by Sanko Co., Ltd., trade name: HCA) is bonded to the phosphorus atom of this compound. A compound obtained by reacting a compound obtained by substituting the active hydrogen atom with hydroquinone (trade name: HCA-HQ, manufactured by Sanko Co., Ltd.) with the above-described epoxy resin is used. As these commercial products, for example, under the trade name, FX305 (manufactured by Toto Kasei Co., Ltd., phosphorus content: 3%), Epicron EXA9710 (manufactured by Dainippon Ink & Chemicals, Inc., phosphorus content: 3%) Etc. The said epoxy resin may be used individually by 1 type, or may use 2 or more types together.

[(B) carboxyl group-containing acrylic resin and / or carboxyl group-containing acrylonitrile-butadiene rubber]

As the component (B), a carboxyl group-containing acrylic resin and / or a carboxyl group-containing acrylonitrile-butadiene rubber (hereinafter, “acrylonitrile-butadiene rubber” is referred to as “NBR”) can be used.
Ratio of carboxyl group in carboxyl group-containing acrylic resin and / or carboxyl group-containing NBR (that is, carboxyl group-containing monomer relative to the total amount of all monomers constituting carboxyl group-containing acrylic resin and / or carboxyl group-containing NBR) ) Is not particularly limited, but is preferably 1 to 10 mol%, more preferably 2 to 6 mol%.

  The carboxyl group-containing acrylic resin that can be used has a glass transition temperature (Tg) of −40 to 30 ° C., and is composed of an acrylic ester as a main component and a monomer having a small amount of carboxyl groups. I just need it. This glass transition temperature (Tg) is preferably -10 to 25 ° C. When the glass transition temperature is −40 to 30 ° C., an appropriate tackiness is imparted to the adhesive, and the handling property is excellent. When the glass transition temperature is less than −40 ° C., the tackiness of the adhesive is large and the handling property is inferior. Moreover, when the glass transition temperature exceeds 30 ° C., the adhesive is inferior in adhesiveness. The glass transition temperature is measured by a differential scanning calorimeter (DSC).

  As for the weight average molecular weight of this acrylic resin, the measured value by gel permeation chromatography (GPC, standard polystyrene conversion) is preferably 100,000 to 1,000,000, and more preferably 300,000 to 850,000.

  The acrylic polymer can be prepared by ordinary solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization, etc., but from the viewpoint of reducing ionic impurities that affect migration resistance as much as possible. Is more preferable.

  Preferable examples of this acrylic resin include copolymerizing three components of (a) acrylic acid ester and / or methacrylic acid ester, (b) acrylonitrile and / or methacrylonitrile, and (c) unsaturated carboxylic acid. The obtained acrylic polymer is mentioned. The acrylic polymer may be a copolymer composed only of the components (a) to (c) or a copolymer containing other components.

-(A) (Meth) acrylic acid ester (a) The acrylic acid ester and / or methacrylic acid ester of the component gives flexibility to the acrylic adhesive composition, and is a specific compound of acrylic acid ester. As, for example, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylate-n-butyl, isobutyl (meth) acrylate, isopentyl (meth) acrylate, (meth) acrylic acid-n -Hexyl, isooctyl (meth) acrylate, (meth) acrylic acid-2-ethylhexyl, (meth) acrylic acid-n-octyl, isononyl (meth) acrylate, (meth) acrylic acid-n-decyl, (meth) Examples include isodecyl acrylate. Among them, (meth) acrylic acid alkyl esters having 1 to 12, particularly 1 to 4 carbon atoms in the alkyl group are preferable. These (a) component (meth) acrylic acid esters may be used alone or in combination of two or more.

  The amount of the component (a) is preferably 50 to 80% by mass and more preferably 55 to 75% by mass in the component (A). When this amount is less than 50% by mass, the flexibility of the adhesive may be impaired. Moreover, when it exceeds 80 mass%, the protrusion of the said composition may generate | occur | produce at the time of press work.

(B) (Meth) acrylonitrile (B) Component acrylonitrile and / or methacrylonitrile impart heat resistance, adhesion and chemical resistance to the adhesive sheet.

  The amount of the component (b) is preferably 15 to 45% by mass and more preferably 20 to 40% by mass in the component (A). When this amount is less than 15% by mass, the adhesive may be inferior in heat resistance. Moreover, when it exceeds 45 mass%, the softness | flexibility of an adhesive agent sheet may be impaired.

-(C) Unsaturated carboxylic acid (c) The unsaturated carboxylic acid of component (c) is a crosslinking monomer at the time of heating as well as providing adhesiveness, and is a copolymerizable vinyl monomer having a carboxyl group Well, specific compounds include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid and the like.

(C) It is preferable that the quantity of a component is 2-10 mass% in (A) component, and 2-8 mass% is more preferable. When this amount is less than 2% by mass, the crosslinking effect may be insufficient. On the other hand, when the amount exceeds 10% by mass, the composition is too cross-linked and poorly adapted to the adherend, which may cause bubbles and blisters during heat curing or solder bath treatment.
The ratio of the carboxyl group in the carboxyl group-containing acrylic resin (that is, the ratio of the monomer unit containing a carboxyl group to all monomers constituting the carboxyl group-containing acrylic resin) is not particularly limited, but preferably 1 to 1 It is 10 mol%, particularly preferably 2 to 6 mol%.
As such a carboxyl group-containing acrylic resin, for example, under the trade name, Paracron ME-3500-DR (manufactured by Negami Kogyo Co., Ltd., glass transition temperature -35 ° C., weight average molecular weight 600,000, containing —COOH), Teisan Resin WS023DR ( Made by Nagase ChemteX, glass transition temperature -5 ° C, weight average molecular weight 450,000, containing -OH / -COOH, Teisan Resin SG-280DR (manufactured by Nagase ChemteX, glass transition temperature -30 ° C, weight average molecular weight 900,000, -COOH-containing), Teisan Resin SG-708-6DR (manufactured by Nagase ChemteX, glass transition temperature 5 ° C, weight average molecular weight 800,000, -OH / -COOH-containing). The said acrylic resin may be used individually by 1 type, or may use 2 or more types together.

  As the carboxyl group-containing NBR that can be used in the present invention, for example, acrylonitrile and butadiene, the amount of acrylonitrile relative to the total amount of acrylonitrile and butadiene is preferably 5 to 70% by mass, particularly preferably 10 to 50% by mass. Examples thereof include those obtained by carboxylating the molecular chain terminal of a copolymer rubber copolymerized so as to have a ratio, or a copolymer rubber of acrylonitrile and butadiene with a carboxyl group-containing monomer such as acrylic acid or maleic acid. For this carboxylation, for example, a monomer having a carboxyl group such as methacrylic acid can be used.

  The ratio of the carboxyl group in the carboxyl group-containing NBR (that is, the ratio of the monomer unit having the carboxyl group to the total monomers constituting the carboxyl group-containing NBR) is not particularly limited, but preferably 1 -10 mol%, particularly preferably 2-6 mol%. When this ratio satisfies the range of 1 to 10 mol%, the fluidity of the resulting composition can be controlled, so that good curability can be obtained.

  As such a carboxyl group-containing NBR, for example, Nipol 1072 (manufactured by Nippon Zeon Co., Ltd.) or PNR-1H (manufactured by JSR), which is a high purity product with a small amount of ionic impurities, can be used. High-purity carboxyl group-containing acrylonitrile butadiene rubber is expensive and cannot be used in large quantities, but is effective in that it can simultaneously improve adhesion and migration resistance.

  Although the compounding quantity of (B) component is not specifically limited, It is 10-200 mass parts normally with respect to 100 mass parts of (A) component, Preferably it is 20-150 mass parts. When the component (B) satisfies the range of 10 to 200 parts by mass, the obtained flexible copper-clad laminate, coverlay and adhesive sheet are excellent in flame retardancy and peel strength with copper foil.

  The carboxyl group-containing acrylic resin and / or the carboxyl group-containing NBR may be used alone or in combination of two or more.

[(C) curing agent]
The curing agent which is component (C) is not particularly limited as long as it is normally used as a curing agent for epoxy resins. Examples of the curing agent include a polyamine curing agent, an acid anhydride curing agent, a boron trifluoride amine complex salt, and a phenol resin. Examples of polyamine curing agents include aliphatic amine curing agents such as diethylenetriamine, tetraethylenetetramine, and tetraethylenepentamine, alicyclic amine curing agents such as isophoronediamine, and aromatic amines such as diaminodiphenylmethane and phenylenediamine. Examples thereof include a system curing agent and dicyandiamide. Examples of the acid anhydride curing agent include phthalic anhydride, pyromellitic acid anhydride, trimellitic acid anhydride, hexahydrophthalic anhydride, and the like. Among them, a polyamine-based curing agent is preferable because appropriate reactivity is required when the obtained composition is used for a coverlay film, and when it is used for a flexible copper-clad laminate, more excellent heat resistance can be imparted. To acid anhydride curing agents are preferred. The said hardening | curing agent may be used individually by 1 type, or may use 2 or more types together.

  Although the compounding quantity of (C) component is not specifically limited, It is 0.5-20 mass parts normally with respect to 100 mass parts of (A) component, Preferably it is 1-15 mass parts.

[(D) Curing accelerator]
In the present invention, the component (D) is not essential, but is preferably added and blended.
The curing accelerator as component (D) is not particularly limited as long as it is used for promoting the reaction between (A) the non-halogen epoxy resin and (C) the curing agent and does not contain a halogen atom. Examples of the curing accelerator include 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, and ethyl isocyanate compounds of these compounds, 2-phenylimidazole, 2-phenyl-4-methylimidazole. Imidazole compounds such as 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, triphenylphosphine, tributylphosphine, tris (p-methylphenyl) phosphine, tris (p -Methoxyphenyl) phosphine, tris (p-ethoxyphenyl) phosphine, triphenylphosphine / triphenylborate, tetraphenylphosphine / tetraphenylborate Honiumu salts, tertiary amines such as triethylene ammonium triphenyl borate, and tetra-boronic acid salts; tin octylate, octoate salts such as zinc octylate and the like. These curing accelerators may be used alone or in combination of two or more.

  Although the compounding quantity of (D) component is not specifically limited, It is 0.1-15 mass parts normally with respect to 100 mass parts of (A) component, Preferably it is 0.5-10 mass parts, Most preferably 1 to 5 parts by mass.

[(E) Phosphinates represented by the general formula (1) and the general formula (2)]
The phosphinic acid salt represented by the general formula (1) and / or the diphosphinic acid salt represented by the general formula (2) (hereinafter referred to as phosphinic acid salts) does not contain a halogen atom and imparts flame retardancy. It is an ingredient.

Among the phosphinic acid salts, in the compounds represented by the general formulas (1) and (2), R ₁ and R ₂ are preferably an alkyl group having 1 to 3 carbon atoms, and preferably an ethyl group. More preferably, M is particularly preferably aluminum. R ₃ in the general formula (2) is preferably an alkyl group having 1 to 3 carbon atoms, more preferably an ethyl group.

  Phosphinates have a high phosphorus content and a particularly high flame retardancy. In addition, phosphinic acid salts are insoluble in organic solvents such as methyl ethyl ketone, toluene, dimethylacetamide, and epoxy resin components commonly used in adhesive varnishes. There is an advantage that bleeding or the like hardly occurs when the film is heat-press cured. The phosphinic acid salts used in the present invention preferably have an average particle size of 20 μm or less, more preferably 0.1 μm or more and 10 μm or less. If the average particle size of the phosphinic acid salt is too large or too small, the dispersibility in the composition of the present invention may be deteriorated, resulting in problems in flame retardancy, heat resistance, and insulation. As a commercial item of the said phosphinates, Exolit OP930 (The product made from Clariant, diethylphosphinic acid aluminum salt, phosphorus content rate 23 mass%) etc. are mentioned by a brand name, for example. Here, the “average particle diameter” is a volume average particle diameter measured by a laser diffraction scattering method.

  In addition to the phosphinates, other phosphorus flame retardants can be used in combination as long as the migration resistance is not deteriorated. However, it is desirable to use the phosphinates alone, and the phosphate esters have migration resistance. In order to worsen, it is not desirable to use phosphate esters together.

  (E) Although the compounding quantity of a component is not specifically limited, From a viewpoint of ensuring favorable flame retardance, Preferably it is 2.0 as phosphorus content rate with respect to the organic resin component except the inorganic solid component in adhesive composition. It is necessary that it is -4.5 mass%, and it is more preferable that it is 2.5-4.0 mass%. When this proportion is less than 2.0% by mass, it is difficult to satisfy the flame retardancy of the obtained adhesive composition, and when it exceeds 4.5% by mass, the heat resistance of the obtained adhesive composition is lowered. To do. Specifically explaining the inorganic solid component and the organic resin component in the adhesive composition, examples of the inorganic solid component include (F) an ion scavenger and an inorganic filler described later. For example, (A) non-halogen epoxy resin, (B) carboxyl group-containing acrylic resin and / or carboxyl group-containing acrylonitrile-butadiene rubber, (C) curing agent, (D) curing accelerator, (E) the above general formula (1) and the phosphinic acid salt shown by the said General formula (2), and (F) heavy metal deactivator are mentioned.

[(F) ion scavenger and / or heavy metal deactivator]
The ion scavenger and / or metal deactivator as the component (F) further improves the migration resistance.

  The ion scavenger is a compound having an ion scavenging ability, and reduces ionic impurities by capturing a phosphate anion, an organic acid anion, a halogen anion, an alkali metal cation, an alkaline earth metal cation, and the like. . When a large amount of ionic impurities are contained, the corrosion of the wiring and the migration resistance of the insulating layer are significantly reduced. Specific examples of such ion scavengers include hydrotalcite ion scavengers, bismuth oxide ion scavengers, antimony oxide ion scavengers, titanium phosphate ion scavengers, and zirconium phosphate ion scavengers. Can be mentioned. Examples of commercially available ion scavengers include DHT-4A (manufactured by Kyowa Chemical Industry, hydrotalcite ion scavenger), IXE-100 (manufactured by Toagosei Co., Ltd., zirconium phosphate ion scavenger), and IXE-300. (Toagosei, antimony oxide ion scavenger), IXE-400 (Toagosei, titanium phosphate ion scavenger), IXE-500 (Toagosei, bismuth oxide ion scavenger), IXE-600 ( Toagosei Co., Ltd., antimony oxide / bismuth oxide ion scavenger), and the like.

  The heavy metal deactivator suppresses the elution of copper ions and improves the migration resistance by inactivating the surface of the copper wiring of the flexible printed wiring board. Specific examples of such heavy metal deactivators include nitrogen compounds such as hydrazides and triazoles. Examples of commercially available heavy metal deactivators include Irganox MD1024 (manufactured by Ciba Specialty Chemicals, hydrazide heavy metal deactivator), BT-120 (manufactured by Johoku Chemical, benzotriazole heavy metal deactivator), and the like. Can be mentioned.

  Said ion-trapping agent and heavy metal deactivator may be used individually by 1 type, or may use 2 or more types together.

  Although the compounding quantity of (F) component is not specifically limited, It is 0.1-5 mass parts normally with respect to 100 mass parts of (A) component, Most preferably, it is 0.5-3 mass parts.

[Other optional ingredients]
In addition to the components (A) to (F), other components may be added as long as the objects and effects of the present invention are not impaired.

-Inorganic filler An inorganic filler can be used together as fillers other than the phosphinic acid salt of the said (E) component. The inorganic filler is not particularly limited as long as it is conventionally used for an adhesive sheet, a coverlay film and a flexible copper-clad laminate. Specific examples thereof include metal oxides such as aluminum hydroxide, magnesium hydroxide, silicon dioxide, and molybdenum oxide from the point of acting also as a flame retardant aid, preferably aluminum hydroxide, magnesium hydroxide. Is mentioned. These inorganic fillers may be used alone or in combination of two or more. Although the compounding quantity of the said inorganic filler is not specifically limited, Preferably it is 5-50 mass parts with respect to a total of 100 mass parts of the organic resin component in adhesive composition, More preferably, it is 10-40 mass parts. .

Organic solvent The above components (A) to (F) and components added as necessary may be used in the production of flexible copper-clad laminates, coverlay films, and adhesive sheets without solvent. The composition may be dissolved or dispersed in the composition and the composition may be prepared and used as a solution or dispersion (hereinafter simply referred to as “solution”). Examples of the organic solvent include N, N-dimethylacetamide, methyl ethyl ketone, N, N-dimethylformamide, cyclohexanone, N-methyl-2-pyrrolidone, toluene, methanol, ethanol, isopropanol, acetone, and the like. N-dimethylacetamide, methyl ethyl ketone, N, N-dimethylformamide, cyclohexanone, N-methyl-2-pyrrolidone, toluene, particularly preferably N, N-dimethylacetamide, methyl ethyl ketone, and toluene. These organic solvents may be used alone or in combination of two or more.

  The total concentration of the organic resin component and the inorganic solid component in the adhesive solution is usually 10 to 45% by mass, preferably 20 to 40% by mass. When this concentration satisfies the range of 10 to 45% by mass, the adhesive solution is excellent in workability because it has good applicability to a substrate such as an electrically insulating film, and there is no unevenness during coating. It is excellent in coating property and excellent in environmental aspect and economical efficiency.

  The “organic resin component” is a non-volatile organic component that constitutes a cured product obtained by curing the adhesive composition of the present invention. Specifically, the components (A) to (E) are mainly used. And (F) a heavy metal deactivator of the component, including an optionally added component. When the organic solvent is included, the organic solvent is usually not included in the organic resin component. The “inorganic solid component” is a non-volatile inorganic solid component contained in the composition. Specifically, it is an ion scavenger of component (F) and an optional inorganic filler. Ingredients also included.

  What is necessary is just to mix the organic resin component in this composition, and the inorganic solid component and the organic solvent added depending on the case using a pot mill, a ball mill, a homogenizer, a super mill, etc.

<Coverlay film>
The said composition can be used for manufacture of a coverlay film. Specifically, for example, a cover lay film having an electrically insulating film and a layer made of the adhesive composition provided on at least one surface of the film can be mentioned. The coverlay film can be provided with a protective layer for protecting the layer on the adhesive composition layer as an optional member. Moreover, when an electrically insulating film is thin, the support body layer for reinforcing it can also be affixed with the adhesive agent of this film.

Hereinafter, the manufacturing method of a coverlay film is demonstrated.
An adhesive solution prepared by mixing a required component and an organic solvent in advance to form a liquid is applied to an electrically insulating film using a reverse roll coater, a comma coater, or the like. The electrically insulating film coated with the adhesive solution is passed through an in-line dryer, and dried by removing the organic solvent at 80 to 160 ° C. over 2 to 10 minutes to obtain a semi-cured state. Next, a coverlay film is obtained by pressing and laminating this semi-cured adhesive composition layer with a release substrate that functions as a protective layer of the composition layer using a roll laminator. The release substrate is peeled off during use. The “semi-cured state” means a state in which the composition is in a dry state and a curing reaction proceeds in a part of the composition.

  The thickness after drying of the adhesive composition layer of the coverlay film is usually 5 to 45 μm, preferably 5 to 35 μm.

-Electrical insulation film The said electrical insulation film is used also for the flexible copper clad laminated board of this invention. This electrical insulating film is not particularly limited as long as it is usually used for a flexible copper clad laminate or a coverlay film. Specifically, for example, based on polyimide film, aramid film, polyethylene terephthalate film, polyethylene naphthalate film, polyester film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, glass fiber, aramid fiber, polyester fiber, etc. Then, impregnated with an epoxy resin, acrylic resin, or the like as a matrix, and a film or sheet and pasted with a copper foil, etc., heat resistance of the obtained coverlay film, dimensional stability, From the viewpoint of mechanical properties and the like, particularly preferably, a low-temperature plasma-treated polyimide film or a corona-treated aramid film can be suitably used. As a polyimide film, what is normally used for a coverlay film should just be used. The thickness of this electrically insulating film may be any thickness as required, but is preferably 9 to 50 μm. Moreover, as an aramid film, what is necessary is just to be normally used for a coverlay film, The thickness of this aramid film should just use arbitrary thickness as needed, Preferably it is 3 9 μm. In general, an aramid film is superior in that it can be handled as a thinner film because it has a higher tensile elastic modulus than a polyimide film. However, when it is difficult to handle as a thin film, a support film coated with an adhesive, such as a polyethylene terephthalate film, can be attached to the thin film to improve the handleability.

  Therefore, as a representative example of a cover lay film using an aramid film as an electrically insulating film, an electrically insulating film comprising a support film and an aramid film preferably having a thickness of 3 to 9 μm supported on the support film, and the insulating film And a coverlay film having a layer made of the adhesive composition provided on at least one surface of the adhesive film and a release substrate provided on the composition layer.

・ Release substrate (protective layer)
The release substrate is not particularly limited as long as it is a film-like material that protects the adhesive composition layer and can be peeled off from the composition layer as needed without impairing its form. For example, polyethylene (PE) film, polypropylene (PP) film, polymethylpentene (TPX) film, plastic film such as polyester film subjected to release treatment, PE film, polyolefin film such as PP film, TPX film, release Examples include release paper obtained by coating a treated polyester film on one or both sides of a paper material. Although the thickness of a mold release base material is not specifically limited, Usually, it is 25-150 micrometers, Preferably it is 30-140 micrometers.

<Adhesive sheet>
The said composition can be used for manufacture of an adhesive sheet. Specifically, for example, an adhesive sheet having a layer made of the composition and a release substrate that covers the layer made of the composition and functions as a protective layer can be mentioned. As the release substrate, those described as the protective layer of the coverlay film can be used. The thickness of the adhesive layer after drying is usually 5 to 50 μm, preferably 10 to 40 μm. Although the thickness of a mold release base material is not specifically limited, Usually, it is 25-150 micrometers, Preferably it is 30-140 micrometers.
Hereinafter, the manufacturing method of the adhesive sheet of this invention is demonstrated.

  The adhesive composition of the present invention prepared as a solution by mixing required components and an organic solvent in advance is applied to a release substrate using a reverse roll coater, a comma coater or the like. The release substrate coated with the adhesive solution is passed through an in-line dryer and dried by removing the organic solvent at 80 to 160 ° C. over 2 to 10 minutes to obtain a semi-cured state. Next, the semi-cured composition layer is pressure-bonded to another release substrate using a roll laminator and laminated. Thus, an adhesive sheet is obtained.

<Flexible copper-clad laminate>
The composition of this invention can be used for manufacture of a flexible copper clad laminated board. Specifically, for example, an electrically insulating film, a layer made of the above-described composition provided on one or both surfaces of the electrically insulating film, one layer bonded to one or two layers of the composition layer, or A flexible copper-clad laminate having two layers of copper foil is exemplified. As the electrical insulating film, those described as the electrical insulating film of the coverlay film can be used. The manufacturing method will be described below.

  The adhesive composition of the present invention prepared as a solution by mixing required components and an organic solvent in advance is applied to an electrically insulating film using a reverse roll coater, a comma coater or the like. The electrically insulating film coated with the adhesive solution is passed through an in-line dryer, and dried by removing the organic solvent at 80 to 160 ° C. over 2 to 10 minutes to obtain a semi-cured state. Next, a copper foil is disposed on the semi-cured composition layer, and a laminate is obtained by heat lamination (thermocompression bonding) at 100 to 150 ° C. The laminate is further post-cured at 80 to 160 ° C. to completely cure the semi-cured composition, thereby obtaining a flexible copper-clad laminate.

  The thickness of the composition layer of the flexible copper-clad laminate after drying is usually 5 to 45 μm, preferably 5 to 18 μm.

  As said copper foil, the rolled copper foil and electrolytic copper foil conventionally used for the flexible copper clad laminated board can be used. The thickness of this copper foil is usually 3 to 70 μm.

EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, these Examples do not limit this invention at all. The components (A) to (F) and other optional components used in the examples are specifically as follows. In addition, the unit of the numerical value which shows the compounding ratio in a table | surface is a "mass part."

<Adhesive composition components>
(A) Non-halogen epoxy resin (1) Epicoat 828 (trade name) (manufactured by Japan Epoxy Resin, epoxy equivalent: 184-194)
(2) Epicoat 1001 (trade name) (manufactured by Japan Epoxy Resin, epoxy equivalent: 450-500)
(3) EOCN-103S (trade name) (manufactured by Nippon Kayaku, epoxy equivalent: 209 to 219)
(4) NC-3000-H (trade name) (manufactured by Nippon Kayaku, epoxy equivalent: 280-300)
(5) EP-49-20 (trade name) (Asahi Denka, epoxy equivalent: 200)

(B) carboxyl group-containing acrylic resin and / or carboxyl group-containing acrylonitrile-butadiene rubber (1) Nipol 1072 (trade name) (manufactured by Nippon Zeon, carboxyl group-containing NBR)
(2) Taisan Resin SG-708-6DR (trade name) (manufactured by Nagase ChemteX, carboxyl group-containing acrylic resin)

(C) Curing agent (1) 4,4′-diaminodiphenyl sulfone (DDS, diamine curing agent)
(2) Phenolite TD-2093 (trade name) (manufactured by Dainippon Ink & Chemicals, novolak type phenol resin, OH equivalent: 104)

・ (D) Curing accelerator (1) 2E4MZ (trade name) (made by Shikoku Kasei Kogyo Co., Ltd., imidazole curing accelerator)

(E) Phosphinic acid salts (1) Exolit OP930 (trade name) (manufactured by Clariant, diethylphosphinic acid aluminum salt, phosphorus content: 23% by mass)

・ (F) Ion scavenger, heavy metal deactivator (1) DHT-4A (trade name) (manufactured by Kyowa Chemical, magnesium, aluminum, hydroxide, carbonate, hydrate (Mg _4.3 Al ₂ (OH) _12.6 CO ₃・ MH ₂ O), ion scavenger)
(2) BT-120 (trade name) (Johoku Chemical Co., Ltd., 1,2,3-benzotriazole, heavy metal deactivator)

・ Inorganic filler (1) Aluminum hydroxide

・ Other phosphorus-based flame retardant PX-200 (trade name) (Daihachi Chemical Industry Co., Ltd., aromatic condensed phosphate ester, phosphorus content: 9.0% by mass)
SP-703 (trade name) (manufactured by Shikoku Kasei Kogyo Co., Ltd., aromatic phosphate ester amide, phosphorus content: 10% by mass)
SPE-100 (trade name) (Otsuka Chemical Co., Ltd., phosphazene, phosphorus content: 13% by mass)

<Characteristics of flexible copper-clad laminate and coverlay film>
[Example 1]
-Preparation of adhesive composition The components of the adhesive composition are mixed in the proportions shown in the column of Formulation Example 1 in Table 1, and a methyl ethyl ketone / toluene mass ratio 1/1 mixed solvent is added to the resulting mixture. Thus, a dispersion having a total concentration of the organic solid component and the inorganic solid component of 35% by mass was prepared.

-Preparation of flexible copper clad laminate On the polyimide film A (trade name: Kapton, manufactured by Toray DuPont, thickness: 25 μm), the dispersion liquid was dried with the applicator to a thickness of 18 μm. The composition was made into a semi-cured state by being applied in a dry state at 120 ° C. for 10 minutes in a blowing oven. After combining the dispersion-coated surface of polyimide film A and the roughened surface of rolled copper foil (Nikko Metal, thickness: 18 μm), and thermocompression bonding them with a roll laminator at 120 ° C. and a linear pressure of 20 N / cm A flexible copper clad laminate was prepared by post-curing at 80 ° C. for 1 hour and further at 160 ° C. for 4 hours.

-Preparation of coverlay film On the surface of polyimide film A (trade name: Kapton, manufactured by Toray DuPont, thickness: 25 μm) so that the thickness after drying of the adhesive composition is 25 μm with the applicator It was applied and dried at 120 ° C. for 10 minutes in a blowing oven to make the composition semi-cured to produce a coverlay film.

[Example 2]
A flexible copper clad laminate and a coverlay film were produced in the same manner as in Example 1 except that the components of the adhesive composition were mixed in the proportions shown in the column of Formulation Example 2 in Table 1.

Example 3
A flexible copper clad laminate and a coverlay film were produced in the same manner as in Example 1 except that the components of the adhesive composition were mixed in the proportions shown in the column of Formulation Example 3 in Table 1.

Example 4
-Preparation of flexible copper clad laminate A mixture of the components of the adhesive composition in the proportions shown in the column of Formulation Example 1 in Table 1 was dispersed in the mixed solvent used in Example 1, and the resulting organic After drying the above adhesive composition with an applicator on an aramid film (trade name: Aramika, Teijin Advanced Film, thickness: 4 μm), a dispersion having a total concentration of solid component and inorganic solid component of 35% by mass The composition was applied to a thickness of 10 μm and dried in a blowing oven at 120 ° C. for 10 minutes to make the composition semi-cured. The surface of the aramid film dispersion applied and the roughened surface of the electrolytic copper foil (Mitsui Metals, thickness: 9 μm) were thermocompression bonded at 120 ° C. and a linear pressure of 20 N / cm with a roll laminator. A flexible copper-clad laminate was prepared by post-curing for 4 hours at 160 ° C. for an additional time.

-Preparation of cover lay film Aramid film (trade name: Aramika, manufactured by Teijin Advanced Film, thickness: 4 μm) so that the thickness of the adhesive composition after drying the adhesive composition is 10 μm with an applicator The composition was semi-cured by applying it to the surface and drying it in a blowing oven at 120 ° C. for 10 minutes to prepare a coverlay film.

[Comparative Examples 1-9]
In each comparative example, a flexible copper-clad laminate and a coverlay film were produced in the same manner as in Example 1 except that the components of the adhesive composition were mixed in the proportions shown in the respective columns of Comparative Formulation Examples 1 to 9 in Table 1. did.

[Comparative Example 10]
A flexible copper clad laminate and a coverlay film were produced in the same manner as in Example 4 except that the components of the adhesive composition were mixed in the proportions shown in the column of Formulation Comparative Example 2 in Table 1.

[Measurement]
The characteristics of the flexible copper clad laminates produced in Examples 1 to 4 and Comparative Examples 1 to 10 were measured according to the following measurement method 1. The characteristics of the produced coverlay film were measured according to the following measurement method 2. Further, the migration resistance of the flexible copper-clad laminate and the coverlay film was measured according to the following measurement method 3. The results are shown in Table 2.

-Measurement method 1-
1-1. Peel strength In accordance with JIS C6471, after forming a circuit with a pattern width of 1 mm on a flexible copper-clad laminate, the direction of the copper foil (the circuit) is 90 degrees with respect to the surface of the laminate at 25 ° C. The minimum value of the force required for peeling off at a speed of 50 mm / min is measured and shown as the peel strength. However, for the films using an aramid film as the electrically insulating film (Example 4 and Comparative Example 10), the force required for peeling at a speed of 50 mm / min in the direction of 180 degrees with respect to the surface of the laminate. The minimum value was measured and indicated as peel strength.

1-2. Solder heat resistance (normal condition, moisture absorption)
-Under normal conditions: In accordance with JIS C6471, a test piece was prepared by cutting a flexible copper-clad laminate into 25 mm squares, and the test piece was floated on a 300 ° C. solder bath for 30 seconds. When the test piece does not swell, peel off, or discolor, it is evaluated as “good” and indicated by ○, and when at least one of the test piece swells, peels off or discolors occurs, it is evaluated as “bad”. And indicated by ×.

  -Under moisture absorption: A test piece prepared in the same manner as that for measuring solder heat resistance under normal conditions was allowed to stand for 24 hours in an atmosphere of 40 ° C and 90% relative humidity, and then the test piece was placed at 260 ° C. It floated on the solder bath for 30 seconds. When the test piece does not swell, peel off, or discolor, it is evaluated as “good” and indicated by ○, and when at least one of the test piece swells, peels off or discolors occurs, it is evaluated as “bad”. And indicated by ×.

1-3. Flame retardance All copper foil was removed by etching the flexible copper-clad laminate to produce a sample. In accordance with UL94VTM-0 flame retardancy standard, the flame retardancy of the sample was measured. A case where flame retardancy satisfying the UL94VTM-0 standard was evaluated as “good” and indicated by ◯, and a case where the sample did not satisfy the UL94VTM-0 standard was evaluated as “defective” and indicated by ×.

-Measurement method 2-
2-1. Peel strength According to JIS C6471, the glossy surface of rolled copper foil (Nikko Metal, thickness: 18 μm) and the adhesive layer of the coverlay film are pressed (temperature: 160 ° C., pressure: 3 MPa, time: 30) A press sample was prepared by laminating using a method. The obtained press sample was cut into a size of 1 cm in width and 15 cm in length to obtain a test piece. The surface of the electrically insulating film of the test piece is fixed (in the case of an aramid film, the film is easy to cut thinly, so a mending tape is attached to the back of the aramid film to reinforce it), and the copper foil is attached to the copper foil at 25 ° C. The minimum value of the force required to peel off at a rate of 50 mm / min in the direction of 90 degrees with respect to the insulating film surface was measured and indicated as peel strength.

2-2. Solder heat resistance (normal condition, moisture absorption)
As a test piece, except that a test piece prepared by cutting a press sample of a coverlay film prepared in the same manner as that for measuring the peel strength into 25 mm squares was used, the same as in the above measurement method 1-2. The solder heat resistance under normal conditions and moisture absorption was measured.

2-3. Flame retardance All the copper foil was removed by etching the pressed sample to prepare a sample. In accordance with UL94VTM-0 flame retardancy standard, the flame retardancy of the sample was measured. A case where flame retardancy satisfying the UL94VTM-0 standard was evaluated as “good” and indicated by ◯, and a case where the sample did not satisfy the UL94VTM-0 standard was evaluated as “defective” and indicated by ×.

-Measurement method 3-
3-1. Migration resistance (single-layer board evaluation and multilayer board evaluation)

  In each example, an adhesive composition layer (25 μm) was formed on one side of a polyester film, which was prepared in the same manner as in Example 5 below except that the flexible copper-clad laminate, the coverlay film, and the adhesive dispersion liquid of each example were used. A test piece having a single-layer plate structure and a test piece having a multi-layer plate structure were prepared using an adhesive sheet comprising That is,

・ Single-layer board test piece:
A test piece for single-layer plate evaluation having the cross-sectional structure shown in FIG. 1 is prepared. A comb-shaped circuit having a line width / space width = 80 μm / 80 μm is prepared on a flexible copper-clad laminate, and a coverlay film is pressed on the circuit forming surface using a press device. Temperature: 160 ° C., pressure: 3 MPa, pressurization time : A test piece for evaluating a laminated single-layer board is prepared under a condition of 30 minutes. In FIG. 1, 1 is an electrically insulating film derived from a cover lay film, 2 is an adhesive layer derived from a cover lay film, 3 is an adhesive layer derived from a flexible copper clad laminate, and 4 is an electricity derived from a flexible copper clad laminate. The insulating film 5 is a copper circuit.

-Test piece for multilayer board evaluation:
The test piece for multilayer board evaluation which shows a cross-sectional structure in FIG. 2 is produced. After bonding the adhesive layers of the two adhesive sheets on the upper and lower surfaces of the single-layer board evaluation test piece prepared as described above, the polyester film as the protective layer was peeled off from the adhesive layer. Expose. In this way, two glass epoxy plates (thickness: 1 mm) are bonded to the adhesive layers provided on the upper and lower sides of the single-layer plate evaluation test piece so as to sandwich the single-layer plate evaluation test piece from above and below, and the temperature Pressure bonding is performed for 30 minutes at 160 ° C. and a pressure of 3 MPa. In this way, the test piece for multilayer board evaluation is produced. In FIG. 2, 1 to 5 are the same as those in FIG. 1, 6 is an adhesive layer derived from an adhesive sheet, and 7 is a glass epoxy plate.

  With respect to the test piece produced as described above, a DC voltage of 50 V was applied to both poles of the circuit under conditions of a temperature of 85 ° C. and a relative humidity of 85% to evaluate migration resistance (migration tester, manufactured by IMV Co., Ltd.). , MIG-86). When a short circuit (reduction in resistance value) occurs between the conductors within 1,000 hours after voltage application, or when dendrite growth is observed after 1,000 hours, it is evaluated as “Poor” and indicated by x. The case where the resistance value was maintained after 1,000 hours and no dendrite was produced was evaluated as “good” and indicated by ◯.

<Characteristics of adhesive sheet>
Example 5
The components of the adhesive composition were mixed in the proportions shown in the column of Formulation Example 1 in Table 1, and a dispersion was prepared in the same manner as in Example 1. Next, the dispersion was applied to the surface of the polyester film that had been subjected to a release treatment so that the thickness after drying of the composition was 25 μm with an applicator, and dried in a blowing oven at 120 ° C. for 10 minutes. By doing so, the adhesive sheet was produced by setting the composition to a semi-cured state.

[Comparative Example 11]
An adhesive sheet was prepared in the same manner as in Example 5 except that the components of the adhesive composition were mixed at the ratio shown in the column of Comparative Formulation Example 2 in Table 1.

[Measurement]
The properties of the adhesive sheets prepared in Example 5 and Comparative Example 11 were measured according to the following measuring method 4. The results are shown in Table 3.

-Measurement method 4-
4-1. Peel strength Through an adhesive layer obtained by removing the polyester film as a protective layer from the adhesive sheet, polyimide film B (trade name: Apical, Kaneka, thickness: 75 μm) and polyimide film C (trade name: Apical, Kaneka) Manufactured and having a thickness of 25 μm), a press sample is prepared by bonding using a press device (temperature: 160 ° C., pressure: 3 MPa, time: 60 minutes). The sample was cut into a size of 1 cm in width and 15 cm in length to obtain a test piece. A polyimide film B (thickness: 75 μm) of the test piece was fixed, and a polyimide film C (thickness: 25 ° C.) The minimum value of the force required to peel 25 μm) at a rate of 50 mm / min in the direction of 180 degrees with respect to the surface of the polyimide film B is measured and shown as the peel strength.

<Evaluation>
The compositions prepared in Formulation Examples 1, 2, and 3 satisfy the requirements of the present invention, and the flexible copper-clad laminate, coverlay, and adhesive sheet using the composition are peel strength, solder heat resistance, Excellent flame retardancy and migration resistance.

  The composition prepared in Comparative Formulation Example 1 was inferior in migration resistance in laminate evaluation because the (F) ion scavenger or heavy metal deactivator required for the present invention was insufficient.

  The composition prepared in Comparative Formulation Example 4 does not contain (E) phosphinates and (F) ion scavengers or heavy metal deactivators, which are requirements of the present invention, and is inferior in peel strength and migration resistance. It was a thing.

  The compositions prepared in Comparative Formulation Example 2, Comparative Formulation Example 6 and Comparative Formulation Example 8 did not contain the (E) phosphinates required for the present invention, and were inferior in peel strength and migration resistance. . In addition, since a phosphorus-based flame retardant having a lower phosphorus content than the (E) phosphinates of the present invention is used, the flame retardant is inferior despite the addition of the same amount of flame retardant as in Formulation Example 1. Met.

  The compositions prepared in Comparative Formulation Example 3, Comparative Formulation Example 5, Comparative Formulation Example 7 and Comparative Formulation Example 9 do not contain (E) phosphinic acid salts which are the requirements of the present invention, and are excellent in peel strength and migration resistance. It was inferior.

  The cured product obtained by curing the flame-retardant adhesive composition of the present invention, and the coverlay film, adhesive sheet and flexible copper-clad laminate using the composition are all peel strength, solder heat resistance and difficulty. Not only has excellent flammability, but also excellent migration resistance in the single-layer board state that has been frequently used in the past, as well as excellent migration resistance in the higher-density multilayer board state, and does not contain halogen. Therefore, it is expected to be applied to the production of environment-friendly flexible printed wiring boards.

It is a longitudinal cross-sectional view which shows the outline of the cross-section of the test piece for a migration resistance test (single-layer board evaluation). It is a longitudinal cross-sectional view which shows the outline of the cross-sectional structure of the test piece for a migration resistance test (multilayer board evaluation).

Explanation of symbols

1 Electrical insulating film (derived from coverlay film)
2 Adhesive layer (from coverlay film)
3 Adhesive layer (derived from flexible copper clad laminate)
4 Electrical insulating film (derived from flexible copper-clad laminate)
5 Conductor (Copper circuit)
6 Adhesive sheet 7 Glass epoxy board

Claims (9)

(A) non-halogen epoxy resin,
(B) a carboxyl group-containing acrylic resin and / or a carboxyl group-containing acrylonitrile-butadiene rubber,
(C) a curing agent,
(E) Phosphinic acid salt represented by the following general formula (1) and / or diphosphinic acid salt represented by the following general formula (2)

(1)
(In the formula, R ₁ and R ₂ may be the same or different, and are a monovalent linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group, and M is Mg, Ca, Al , Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, and a protonated nitrogen base, and m is 1 It is an integer of ~ 4.)

(2)
Wherein R ₁ , R ₂ , M and m are as described above, R ₃ is a divalent linear or branched alkylene group having 1 to 10 carbon atoms, and arylene having 6 to 10 carbon atoms. A group, an alkylarylene group having 6 to 10 carbon atoms, or an arylalkylene group having 6 to 10 carbon atoms, n is an integer of 1 to 4, and x is an integer of 1 to 4, provided that 2n = mx)), and (F) a flame retardant adhesive composition comprising an ion scavenger and / or a heavy metal deactivator.   The adhesive sheet which has a mold release base material and the layer which consists of an adhesive composition of Claim 1 formed in the single side | surface of this base material.   The coverlay film which has a layer which consists of an electrically insulating film and the composition of Claim 1 provided in the at least single side | surface of this insulating film.   The coverlay film according to claim 3, wherein the electrically insulating film includes a polyimide film or an aramid film.   The coverlay film according to claim 4, wherein the electrically insulating film comprises a support film and an aramid film having a thickness of 3 to 9 μm supported on the support film.   An electrically insulating film made of an aramid film having a thickness of 3 to 9 μm supported on a support film, a layer made of the composition according to claim 1 provided on at least one surface of the insulating film, and the composition layer The coverlay film according to claim 5, further comprising a release substrate provided thereon.   An electrically insulating film, a layer comprising the adhesive composition according to claim 1 provided on one or both sides of the insulating film, and a single or two-layer adhesive composition layer thus provided. A flexible copper clad laminate having a single layer or two layers of copper foil.   The flexible copper clad laminate according to claim 7, wherein the electrical insulating film includes a polyimide film or an aramid film.   The flexible copper-clad laminate according to claim 8, wherein the electrical insulating film comprises a support film and an aramid film having a thickness of 3 to 9 μm supported on the support film.

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