JP2010018676A - Flame-retardant adhesive composition and adhesion sheet using the same, coverlay film, and flexible copper-clad laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition excellent in flame retardancy, migration resistance, adhesiveness and heat resistance while being halogen-free, to provide an adhesive sheet using the composition, to provide a coverlay film and to provide a print board material such as a copper-clad laminate. <P>SOLUTION: The flame-retardant adhesive composition includes a halogen-free epoxy resin (A), a synthetic rubber (B), a hardener (C), and a specific phosphorus-containing benzoxazine compound (D). The adhesive sheet has a release substrate, and a layer formed of the composition provided on at least one side of the substrate. The coverlay film has an electric insulation film, and a layer formed of the composition provided on at least one side of the electric insulation film. The flexible copper-clad laminate has an electric insulation film, a layer or layers formed of the composition provided on one side or both sides of the electric insulation film, and one layer or two layers of copper foil on the one layer or two layers of the composition thus provided. <P>COPYRIGHT: (C)2010,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 laminate using the composition It is about a 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, flame resistance, and the like. Also, the adhesive sheet is 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 to attach a reinforcing plate or the like to the flexible printed wiring board. The properties required for the adhesive sheet include adhesive strength, heat resistance, and the like.

  With the recent environmental problems, bromine compounds that tend to suppress the use of halogen compounds in components mounted on electronic equipment and have been used extensively in the past to make flexible printed wiring board materials flame-retardant The use of has become difficult.

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) mainly composed of an epoxy resin, a phosphate ester compound, a phenolic curing agent, and NBR rubber has been proposed. However, since ordinary phosphoric acid esters are soluble in common solvents, the glass transition temperature of the cured product is lowered, and the solvent resistance of the substrate is insufficient. Moreover, since phosphate ester is inferior in heat-and-moisture resistance, the phosphate ester hydrolyzed under high-temperature and high-humidity conditions to produce an ionic component, and the migration resistance of the substrate was insufficient.
JP 2001-339131 A

  Therefore, the present invention provides an adhesive composition excellent in flame retardancy, migration resistance, adhesion, heat resistance, and solvent resistance while being non-halogen, and an adhesive sheet, coverlay film, copper-clad using the composition. It aims at providing printed circuit board materials, such as a laminated board.

  As a result of intensive studies to achieve the above problems, the present inventors have found that the above problems can be solved by adopting a specific phosphorus-containing benzoxazine compound as an essential component as a flame retardant component. The present invention has been completed.

That is, the present invention firstly
(A) non-halogen epoxy resin,
(B) synthetic rubber,
(C) a curing agent, and (D) the following formula (1):

（1）
で示されるリン含有ベンゾオキサジン化合物
を含む難燃性接着剤組成物を提供する。

(1)
A flame retardant adhesive composition comprising a phosphorus-containing benzoxazine compound represented by the formula:

  Secondly, the present invention provides an adhesive sheet having a release substrate and a layer made of the above composition provided on at least one surface of the substrate. The adhesive sheet is obtained by applying the composition to a substrate having releasability.

  Thirdly, the present invention provides a coverlay film having an electrically insulating film and a layer made of the above composition provided on at least one surface of the electrically insulating film. The coverlay film is obtained by applying the composition onto an electrically insulating film.

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

  In the composition of the present invention, a cured product obtained by curing is excellent in flame retardancy, migration resistance, adhesion, heat resistance and solvent resistance, 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, migration resistance, adhesion, heat resistance, and solvent resistance.

<Flame-retardant adhesive composition>
The flame retardant adhesive composition of the present invention contains the above components (A) to (D).
The method of using the composition of the present invention and the form of use are not limited in any way, but in one of the typical forms of use as an adhesive, the composition is sandwiched between two adherends and these adherends are used. Is used as a layered composition for adhering. A to-be-adhered body is not specifically limited, For example, the combination etc. of the electrically insulating film used for the flexible copper clad laminated board mentioned later and copper foil are mentioned.
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 commercial products, for example, EK (Epicoat) 1001 (manufactured by Japan Epoxy Resin), Epicron 830S (manufactured by Dainippon Ink & Chemicals), EK517 (manufactured by Japan Epoxy Resin), EOCN103S (manufactured by Nippon Kayaku) ) And the like.

  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.

  (A) The non-halogen-type epoxy resin of a component may be used individually by 1 type, or may use 2 or more types together.

[(B) Synthetic rubber]
The (B) component synthetic rubber is not particularly limited and can be used singly or in combination of two or more. Examples of the component (B) include acrylic rubber, acrylonitrile-butadiene rubber (hereinafter, “acrylonitrile-butadiene rubber” is referred to as “NBR”), ethylene-acryl rubber, styrene-butadiene rubber, butadiene-methyl acrylate-acrylonitrile rubber, Synthetic rubbers that do not contain substituents such as butadiene rubber, silicone rubber, urethane rubber, and polyvinyl butyral; synthetic rubbers in which substituents are introduced into synthetic rubbers that do not contain these substituents, such as carboxyl group-containing acrylic resins, carboxyl group-containing NBR And synthetic rubbers containing substituents such as vinyl group-containing NBR and carboxyl group-containing ethylene-acrylic rubber. Among these, carboxyl group-containing acrylic resins, carboxyl group-containing NBR, and carboxyl group-containing ethylene-acrylic rubber are preferable. Hereinafter, in particular, the carboxyl group-containing acrylic resin, the carboxyl group-containing NBR, and the carboxyl group-containing ethylene-acrylic rubber will be described.

<Carboxyl group-containing acrylic resin>
The carboxyl group-containing acrylic resin that can be used in the present invention has a glass transition temperature (Tg) of −40 to 30 ° C., and is mainly composed of an acrylate ester and a monomer having a small amount of carboxyl groups. Anything is acceptable. This glass transition temperature (Tg) is preferably -10 to 25 ° C. When the glass transition temperature is −40 to 30 ° C., the obtained adhesive composition has an appropriate tack and is excellent in handling properties. When the glass transition temperature is lower than −40 ° C., the obtained adhesive composition has a large tack and is inferior in handling properties. Moreover, when a glass transition temperature exceeds 30 degreeC, the adhesive composition obtained is inferior to 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 the acrylic resin include (a) acrylic acid ester, methacrylic acid ester or a combination thereof, (b) acrylonitrile, methacrylonitrile or a combination thereof, and (c) three components of unsaturated carboxylic acid. An acrylic polymer obtained by polymerization is exemplified. The acrylic polymer may be a copolymer composed only of the components (a) to (c) or a copolymer containing other components.

(A) Acrylic acid ester, methacrylic acid ester, or a combination thereof (a) Acrylic acid ester, methacrylic acid ester or a combination thereof as a component imparts flexibility to the adhesive composition, (a) Specific compounds of the components include, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, acrylate-n-butyl, methacrylate-n-butyl, isobutyl acrylate, isobutyl methacrylate, acrylic Isopentyl acid, isopentyl methacrylate, acrylic acid-n-hexyl, methacrylic acid-n-hexyl, isooctyl acrylate, isooctyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, n-octyl acrylate, Methacryl Examples include acid-n-octyl, isononyl acrylate, isononyl methacrylate, acrylic acid-n-decyl, methacrylic acid-n-decyl, isodecyl acrylate, and isodecyl methacrylate. Among these, acrylic acid esters and methacrylic acid esters having an alkyl group having 1 to 12 carbon atoms, particularly 1 to 4 carbon atoms are preferable. Each of the (a) component acrylic acid ester and methacrylic acid ester may be used alone or in combination of two or more.

  The amount of the component (a) is preferably 50 to 80% by mass in the component (B), and more preferably 55 to 75% by mass. When this amount is less than 50% by mass, the flexibility of the resulting composition 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) Acrylonitrile, methacrylonitrile or a combination thereof (b) Component acrylonitrile, methacrylonitrile or a combination thereof imparts heat resistance, adhesiveness 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 (B). When this amount is less than 15% by mass, the resulting cured product may be inferior in heat resistance. Moreover, when it exceeds 45 mass%, the softness | flexibility of an adhesive sheet may be impaired.

-(C) Unsaturated carboxylic acid (c) The unsaturated carboxylic acid of component (c) provides adhesion to the resulting composition, and at the same time serves as a crosslinking point during heat curing, and can be copolymerized with a carboxyl group. Specific examples of the compound include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid. (C) The unsaturated carboxylic acid of a component may be used individually by 1 type, or may use 2 or more types together.

  The amount of the component (c) is preferably 2 to 10% by mass and more preferably 2 to 8% by mass in the component (B). If this amount is less than 2% by mass, the effect of crosslinking formation 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.

  As such a carboxyl group-containing acrylic resin, for example, under the trade name, Paracron ME-3500-DR (manufactured by Negami Kogyo, 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.

<Carboxyl group-containing NBR>
As the carboxyl group-containing NBR that can be used in the present invention, for example, acrylonitrile and butadiene, the amount of acrylonitrile with respect 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 achieved.

  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 NBR is expensive and cannot be used in a large amount, but is effective in that it can simultaneously improve adhesion and migration resistance. The carboxyl group-containing NBR may be used alone or in combination of two or more.

<Carboxyl group-containing ethylene-acrylic rubber>
The carboxyl group-containing ethylene-acrylic rubber that can be used in the present invention includes an ethylene monomer unit and an acrylate monomer unit, a methacrylic acid ester monomer unit, or a combination thereof and a monomer having a carboxyl group. An ethylene-acrylic rubber composed of units can be used. Examples of the acrylate monomer unit include a methyl acrylate monomer unit, an ethyl acrylate monomer unit, and a butyl acrylate monomer unit. Examples of the methacrylate ester monomer unit include a methyl methacrylate monomer unit, an ethyl methacrylate monomer unit, and a butyl methacrylate monomer unit. Examples of the monomer unit having a carboxyl group include an acrylic acid monomer unit, a methacrylic acid monomer unit, and a maleic acid monomer unit.

  The ratio of the carboxyl group in the carboxyl group-containing ethylene-acrylic rubber (that is, the ratio of the monomer unit having a carboxyl group to the total monomer units constituting the carboxyl group-containing ethylene-acrylic rubber) is not particularly limited. However, Preferably it is 1-10 mol%, Most preferably, it is 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 achieved.

  As such an ethylene-acrylic rubber, for example, Baymac G (manufactured by Mitsui DuPont Polychemical Co., Ltd., containing —COOH) may be mentioned under the trade name. The said carboxyl group-containing ethylene-acrylic rubber may be used individually by 1 type, or may use 2 or more types together.

  Although the compounding quantity of (B) component is not specifically limited, Preferably it is 10-100 mass parts with respect to 100 mass parts of (A) component, More preferably, it is 20-90 mass parts. When the component (B) satisfies the range of 10 to 100 parts by mass, the obtained flexible copper-clad laminate, coverlay film and adhesive sheet are more excellent in flame retardancy and peel strength from copper foil.

[(C) curing agent]
The curing agent as component (C) is not particularly limited as long as it is usually used as a curing agent for epoxy resins, but from the viewpoint of not deteriorating the flame retardancy of the resulting cured product, an aromatic in the molecular skeleton. A curing agent having a ring is more preferable. (C) As a hardening | curing agent of a component, a polyamine type hardening | curing agent, an acid anhydride type hardening | curing agent, a boron trifluoride amine complex salt, a phenol resin type hardening | curing agent etc. are mentioned, for example. 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 of such a curing agent include dicyandiamide, and as described above, an aromatic amine curing agent is particularly preferable. Examples of the acid anhydride curing agent include phthalic anhydride, pyromellitic acid anhydride, trimellitic acid anhydride, hexahydrophthalic anhydride, and the like. Especially, when using the obtained composition for a coverlay film, since an appropriate reactivity is calculated | required, an aromatic polyamine type hardening | curing agent and a phenol resin type hardening | curing agent are preferable. (C) The hardening | curing agent of a component may be used individually by 1 type, or may use 2 or more types together.

  (C) The compounding quantity of a component becomes like this. Preferably it is 1-150 mass parts with respect to 100 mass parts of (A) component, More preferably, it is 3-100 mass parts. When the blending amount is within this range, the obtained composition is sufficiently cured, and the obtained cured product does not have an excessively high degree of crosslinking, and tends to be excellent in heat resistance and adhesion.

[(D) Phosphorus-containing benzoxazine compound]
The phosphorus-containing benzoxazine compound represented by the general formula (1), which is the component (D), is a component that imparts excellent flame retardancy to the resulting cured product, and does not contain a halogen atom.

  The phosphorus-containing benzoxazine compound of component (D) has a benzoxazine structure and a phosphorus atom in the molecule, and therefore has excellent heat resistance, flame resistance, chemical resistance, and resistance to the resulting cured product. Gives migration.

  (D) As a commercial item of the phosphorus containing benzoxazine compound of a component, HFB2006M (Showa High Polymer Co., Ltd. make, phosphorus content = 7.0 mass%) is mentioned by a brand name, for example.

  In addition to the phosphorus-containing benzoxazine compound of component (D), other phosphorus-based flame retardants can be used in combination, but using component (D) alone from the viewpoint of heat resistance, solvent resistance, and migration resistance desirable.

Although the compounding quantity of (D) component is not specifically limited, as a phosphorus content rate with respect to 100 mass parts of organic resin components except an inorganic solid component in an adhesive composition from a viewpoint of ensuring favorable flame retardance, it is 1 It is preferable that it is 0.0-3.0 mass%, and it is more preferable that it is 1.0-2.5 mass%. When the phosphorus content is within the above range, the resulting adhesive composition tends to have good flame retardancy and adhesion.

  The “organic resin component” is a non-volatile organic component constituting a cured product obtained by curing the adhesive composition of the present invention, and specifically, components (A) to (D) are mainly used. If the adhesive composition contains an organic solvent, 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 adhesive composition of the present invention. Specifically, it is an inorganic filler (described later) that is optionally added. Ingredients are also included.

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

-Inorganic filler The inorganic filler is not particularly limited as long as it is conventionally used for adhesive sheets, coverlay films and flexible copper-clad laminates, but other than the phosphorus-containing benzoxazine compound of the above component (D) Those which can be used in combination as a flame retardant aid are preferred. Specific examples of the inorganic filler are preferably metal oxides such as aluminum hydroxide, magnesium hydroxide, silicon dioxide, and molybdenum oxide, more preferably hydroxylated from the point of acting also as a flame retardant aid. Aluminum and magnesium hydroxide are 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 5-100 mass parts with respect to a total of 100 mass parts of the organic resin component in adhesive composition, More preferably, it is 10-90 mass parts. .

-Hardening accelerator A hardening accelerator will not be specifically limited if it is used for acceleration | stimulation of reaction with (A) non-halogen-type epoxy resin and (C) hardening agent. 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 Tertiary amines such as phonium salts, triethyleneammonium triphenylborate, and tetraphenylborates thereof, borofluorides such as zinc borofluoride, tin borofluoride, nickel borofluoride; tin octylate, zinc octylate, etc. An octylate etc. are mentioned.
The said hardening accelerator may be used individually by 1 type, or may use 2 or more types together.

Organic solvent The components (A) to (D) and components added as necessary may be used in the production of adhesive sheets, coverlay films and flexible copper-clad laminates 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 composition solution is usually 10 to 70% by mass, preferably 20 to 50% by mass. When this concentration satisfies the range of 10 to 70% by mass, the adhesive composition solution is excellent in workability because it has good applicability to a substrate such as an electrical insulating film, and unevenness occurs during coating. It is excellent in coating properties, and in terms of environment and economy.

  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 coverlay film having an electrically insulating film and a layer made of the above 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 on this film with an adhesive agent.

Hereinafter, the manufacturing method of a coverlay film is demonstrated.
A solution of the adhesive composition of the present invention prepared 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 composition 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. The electrical insulating film is not particularly limited as long as it is usually used for flexible copper clad laminates and coverlay films. Specifically, for example, polyimide film; aramid film; polyethylene terephthalate film; polyethylene naphthalate film; polyester film; polyparabanic acid film; polyetheretherketone 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.

・ 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.

<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. Hereinafter, the manufacturing method of the adhesive sheet of this invention is demonstrated.

  A solution of the adhesive composition of the present invention prepared 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 composition 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. In this way, 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, a flexible copper-clad laminate having an electrically insulating film, a layer made of the above composition provided on the film, and a copper foil bonded to the composition layer can be mentioned. As the electrical insulating film, those described as the electrical insulating film of the coverlay film can be used. Hereinafter, the manufacturing method of the flexible copper clad laminated board 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 an electrically insulating film using a reverse roll coater, a comma coater or the like. The electrically insulating film coated with the adhesive composition 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 laminated body is further post-cured at 100 to 180 ° 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 (D) 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) NC-3000-H (trade name) (manufactured by Nippon Kayaku, epoxy equivalent: 280-300)

・ (B) Synthetic rubber (1) Nipol 1072 (trade name) (manufactured by Nippon Zeon, carboxyl group-containing NBR)
(2) Teisan resin SG-708-6 (trade name) (manufactured by Nagase ChemteX, carboxyl group-containing acrylic resin)
(3) Baymac G (trade name) (Mitsui DuPont Polychemical, carboxyl group-containing ethylene-acrylic rubber)

・ (C) Hardener (1) TD-2131 (trade name) (manufactured by Dainippon Ink, phenol resin)

・ (D) Phosphorus-containing benzoxazine compound (1) HFB2006M (trade name) (manufactured by Showa Polymer, phosphorus content 7.0 mass%)

・ Inorganic filler (optional component)
(1) Aluminum hydroxide (made by Showa Denko)

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

・ Phosphorus flame retardant (component for comparison)
(1) PX-200 (trade name) (produced by Daihachi Chemical Industry Co., Ltd., aromatic condensed phosphate ester, phosphorus content: 9.0% by mass)

<Characteristics of flexible copper-clad laminate and coverlay film>
[Example 1]
-Preparation of adhesive composition The components of the adhesive composition were mixed in the proportions shown in the column of Formulation Example 1 in Table 1, and the resulting mixture was mixed in a mass ratio of methyl ethyl ketone / toluene / dimethylacetamide 1/1 / 0.5. By adding a solvent, 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 above dispersion was applied with an applicator so that the thickness after drying was 18 μm, The composition was semi-cured by drying in a blast oven at 120 ° C. for 10 minutes. The dispersion coating surface of polyimide film A and the roughened surface of rolled copper foil (manufactured by Nikko Materials, thickness: 18 μm) were combined, and both were thermocompression bonded with a roll laminator at 120 ° C. and a linear pressure of 20 N / cm. Then, a flexible copper clad laminate was produced by post-curing at 80 ° C. for 1 hour and further at 180 ° C. for 4 hours.

-Production of coverlay film The above dispersion was applied to the surface of polyimide film A (trade name: Kapton, Toray DuPont, thickness: 25 μm) with an applicator so that the thickness after drying was 25 μm. A coverlay film was prepared by drying the composition in a blowing oven at a temperature of 10 ° C. for a semi-cured state.

[Examples 2 to 4]
In each of Examples 2 to 4, a flexible copper clad laminate and a coverlay film were prepared 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 Formulation Examples 2 to 4 in Table 1. Was made.

[Comparative Examples 1 and 2]
In each of Comparative Examples 1 and 2, a flexible copper clad laminate and a coverlay were prepared 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 and 2 in Table 1. A film was prepared.

[Measurement]
The characteristics of the produced flexible copper clad laminate were measured according to the following measurement method 1. Further, the characteristics of the produced coverlay film were measured according to the following measurement method 2. Furthermore, 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 to peel off at a speed of 50 mm / min was measured and indicated as the 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, or discolor, it is evaluated as “good” and indicated by ○, and when at least one of the test piece swells, peels, or discolors occurs, it is evaluated as “bad”. 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, or discolor, it is evaluated as “good” and indicated by ○, and when at least one of the test piece swells, peels, or discolors occurs, it is evaluated as “bad”. 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. When the sample exhibited flame retardancy satisfying the UL94VTM-0 standard, it was evaluated as “good” and indicated by “◯”, and when this sample did not satisfy the UL94VTM-0 standard, it was evaluated as “bad”. Indicated.

[Measurement method 2]
2-1. Peel strength According to JIS C6471, the glossy surface of rolled copper foil (manufactured by Nikko Materials, thickness: 18 μm) and the adhesive composition layer of the coverlay film are pressed (temperature: 180 ° C., pressure: 3 MPa, A press sample was produced by pasting using a time of 60 minutes. 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 electric insulation film surface of the test piece is fixed, and the minimum force required to peel the copper foil at a speed of 50 mm / min in the direction of 90 degrees with respect to the electric insulation film surface under the condition of 25 ° C. The value was measured and expressed as peel strength.

2-2. Solder heat resistance (normal condition, moisture absorption)
As a test piece, under normal conditions and moisture absorption as in the above measurement method 1-2, except that a test piece produced by cutting a press sample produced in the same manner as in the above measurement method 2-1 into 25 mm square was produced. The lower solder heat resistance was measured.

2-3. Flame retardancy All the copper foil was removed by performing an etching process on the press sample produced in the same manner as in the above measuring method 2-1, and a sample for flame retardancy evaluation was produced. In accordance with UL94VTM-0 flame retardancy standard, the flame retardancy of the flame retardancy evaluation sample was measured. When the sample for flame retardancy evaluation showed flame retardancy satisfying the UL94VTM-0 standard, it was evaluated as “good” and indicated by ○, and the sample for flame retardancy evaluation did not satisfy the UL94VTM-0 standard. The case was evaluated as “bad” and indicated by x.

[Measurement method 3]
3-1. Migration resistance A comb-shaped circuit having a line width / space width = 50 μm / 50 μm is prepared on a flexible copper-clad laminate, and an adhesive composition layer of a coverlay film is aligned with the circuit-forming surface. A sample for evaluating migration resistance was prepared by pasting the coverlay film on a press device (temperature: 180 ° C., pressure: 3 MPa, time: 60 minutes).

  Under conditions of a temperature of 85 ° C. and a relative humidity of 85%, a DC voltage of 50 V was applied to both electrodes of the circuit of the sample for evaluation, and migration resistance was evaluated (migration tester, manufactured by IMV, 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 had passed and no dendrite was produced was evaluated as “good” and indicated by ◯.

<Characteristics of adhesive sheet>
Example 5
A dispersion was prepared in the same manner as in Example 1. Next, the dispersion was applied to the surface of the polyester film which had been subjected to a release treatment so that the thickness after drying was 25 μm with an applicator, and then it was dried in a blowing oven at 120 ° C. for 10 minutes. An adhesive sheet was prepared with the product in a semi-cured state.

[Examples 6 to 8]
In each of Examples 6 to 8, an adhesive sheet was prepared in the same manner as in Example 5 except that the components of the adhesive composition were mixed in the proportions shown in the respective columns of Formulation Examples 2 to 4 in Table 1.

[Comparative Examples 3 and 4]
In each of Comparative Examples 3 and 4, an adhesive sheet was prepared in the same manner as in Example 5 except that the components of the adhesive composition were mixed in the proportions shown in the respective columns of Comparative Formulation Examples 1 and 2 in Table 1.

[Measurement]
The characteristics of the prepared adhesive sheet were measured according to the following measuring methods 4 and 5. The results are shown in Table 3.

[Measurement method 4]
4-1. Peel strength Through a composition layer separated from the polyester film of the adhesive sheet, polyimide film B (trade name: Apical, Kaneka, thickness: 75 μm) and polyimide film C (trade name: Apical, Kaneka, thickness: 25 μm), followed by bonding using a press device (temperature: 180 ° C., pressure: 3 MPa, time: 60 minutes) to produce a press sample. 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 was measured and indicated as the peel strength.

[Measurement method 5]
5-1. Glass transition temperature of cured adhesive sheet After the glossy surfaces of rolled copper foil (manufactured by Nikko Materials, thickness: 18 μm) are overlapped with each other through the composition layer separated from the polyester film of the adhesive sheet, a press device ( A press sample was manufactured by bonding using a temperature of 180 ° C., a pressure of 3 MPa, and a time of 60 minutes. All the copper foil was removed by performing an etching process on the press sample, and a sample made of a cured product of the adhesive sheet was obtained. The sample was cut into a size of 1 cm in width and 5 cm in length to obtain a test piece, and by dynamic viscoelasticity measurement (manufactured by Rheometric, RSA III, measurement frequency 5 Hz, tensile mode, tan δ peak was glass transition temperature). The glass transition temperature of the cured product was determined.

<Evaluation>
The compositions prepared in Formulation Examples 1 to 4 satisfy the requirements of the present invention, and a flexible copper-clad laminate, a coverlay film, and an adhesive sheet using the composition are peel strength, solder heat resistance, flame resistance , Migration resistance, heat resistance (glass transition temperature of the cured product) and solvent resistance.

  The composition prepared in Comparative Formulation Example 1 does not contain the phosphorus-containing benzoxazine compound represented by the above general formula (1), which is a requirement of the present invention. The transition temperature was inferior.

  The composition prepared in Comparative Formulation Example 2 does not contain (D) the phosphorus-containing benzoxazine compound represented by the above general formula (1), which is a requirement of the present invention, and a phosphate ester compound which is not a requirement of the present invention. It contained and was inferior to peeling strength, heat resistance (glass transition temperature of hardened | cured material), and migration resistance.

  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, difficulty Since it is excellent in flammability, migration resistance, heat resistance (glass transition temperature of the cured product) and solvent resistance and does not contain halogen, it is expected to be applied to the production of environment-friendly flexible printed wiring boards.

Claims (7)

(A) non-halogen epoxy resin,
(B) synthetic rubber,
(C) a curing agent, and (D) the following formula (1):

(1)
The flame-retardant adhesive composition containing the phosphorus containing benzoxazine compound shown by these.   The composition according to claim 1, wherein the composition is a layered structure that is sandwiched between two adherends to adhere the adherends.   The adhesive sheet which has a mold release base material and the layer which consists of a composition of Claim 1 provided in the at least single side | surface of this base material.   The coverlay film which has an electrically insulating film and the layer which consists of a composition of Claim 1 provided in the at least single side | surface of this electrically insulating film.   The coverlay film according to claim 4, wherein the electrically insulating film is a polyimide film.   An electrically insulating film, a layer made of the composition according to claim 1 provided on one or both sides of the electrically insulating film, and a layer provided on one or two composition layers thus provided Or the flexible copper clad laminated board which has a copper foil of two layers.   The flexible copper-clad laminate according to claim 6, wherein the electrically insulating film is a polyimide film.