JP2006232984A - Adhesive composition, and coverlay film and adhesive sheet obtained using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition giving a cured product excellent in glass transition temperature, peeling strength, soldering heat resistance and processability, and a coverlay film and an adhesive sheet each having an adhesive layer comprised of the composition. <P>SOLUTION: The adhesive composition comprises (A) a phenoxy resin having a molecular weight of at least 10,000, a glass transition temperature of 40°C or higher and bearing epoxy groups on the both ends of the molecular chain, (B) an epoxy resin, (C) a carboxy group-containing NBR having an acrylonitrile content of 20-50 mass% and a carboxy group content of 0.005-5 mass%, (D) a curing agent, (E) an inorganic filler, and (F) a vulcanizing agent, where the ratio of the component (C) to the total of the components (A)-(D) is 10-60 mass% and the ratio of the components having a glass transition temperature of 30°C or higher in the components (A)-(D) is 40-90 mass%. The adhesive sheet and the coverlay film are obtained using the composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an adhesive composition that is a cured product excellent in glass transition point, peel strength, solder heat resistance and processability, and a coverlay film and an adhesive sheet having an adhesive layer made of the composition.

  In recent years, the electronics field has been remarkably developed, and in particular, electronic devices for communication and consumer use have been reduced in size, weight, density, etc., and demands for these performances have become increasingly sophisticated. In response to such requirements, flexible printed wiring boards are flexible and can withstand repeated bending, so they can be mounted three-dimensionally and densely in a narrow space. As a composite part with a connector function and the like, its application is expanding.

  As the flexible printed wiring board, a coverlay film is used in which a semi-cured adhesive is applied to one side of an electrically insulating base film and a release material is bonded together. This cover lay film is for the purpose of circuit protection and flexibility improvement of a flexible printed wiring board, and, for example, characteristics such as storage stability, adhesion, heat resistance, electrical characteristics, and workability are required.

  In addition, when manufacturing a multilayer flexible printed wiring board by bonding a flexible printed wiring board and a flexible printed wiring board, or when bonding a flexible printed wiring board and a reinforcing plate, an adhesive sheet is used as an adhesive material. Is done. This adhesive sheet is obtained by applying a semi-cured adhesive on one side of the release material, or by applying a semi-cured adhesive on one side of the release material, and further bonding the release material. Properties such as storability, adhesion, heat resistance, electrical properties, and workability are required.

  In recent years, the opportunity to use flexible printed wiring boards at high temperatures and the opportunity to mount components by wire bonding has increased, and this has led to a high glass transition point for adhesives used for flexible printed wiring boards. Is becoming necessary.

  Therefore, regarding flexible printed wiring boards, materials using an adhesive having a high glass transition point, materials obtained by bonding a metal foil and a heat-resistant resin without using an adhesive, and the like have been proposed. On the other hand, as for the cover lay film and the adhesive sheet, those using an adhesive having a high glass transition point have been proposed from the viewpoint of processability, storage stability and the like.

  Specific examples thereof include, for example, an adhesive composition composed of a thermoplastic resin, a phosphorus-containing phenoxy resin, a phosphorus-containing epoxy resin and a curing agent (Patent Document 1), an epoxy resin, a curing agent, a phenoxy resin, a rubber component, and a curing accelerator. Resin composition comprising an agent (Patent Document 2), resin composition comprising a phenoxy resin, an epoxy resin and a curing agent (Patent Document 3), an adhesive composition comprising an acrylic rubber, a phenoxy resin and a curing agent (Patent Document 4) An adhesive composition comprising a phosphorus-containing phenoxy resin, an epoxy resin, a carboxyl group-containing butadiene rubber, a curing agent, a curing accelerator, a metal hydroxide and an inorganic filler (Patent Document 5) has been proposed.

  However, in any of the adhesive compositions, the cured product was not excellent in glass transition point, peel strength, solder heat resistance and workability at the same time.

JP 2003-176470 A JP 2003-286391 A JP 11-279260 A JP 2004136663 A JP 2003-292927 A

  Accordingly, the present invention provides an adhesive composition that becomes a cured product having excellent glass transition point, peel strength, solder heat resistance and processability, and a coverlay film and an adhesive sheet having an adhesive layer made of the composition. The purpose is to do.

In order to solve the above problems, the present invention provides:
(A) a phenoxy resin having an epoxy group at both ends of a molecular chain, having a weight average molecular weight of 10,000 or more and a glass transition point of 40 ° C. or more;
(B) an epoxy resin other than the component (A),
(C) a carboxyl group-containing acrylonitrile-butadiene rubber having an acrylonitrile content of 20 to 50% by mass and a carboxyl group content of 0.005 to 5% by mass,
(D) a curing agent,
(E) An adhesive composition comprising an inorganic filler and (F) a metal oxide vulcanizing agent, wherein the component (C) is added to the total of the components (A) to (D). The above composition wherein the proportion is 10 to 60% by mass, and the blending amount of the component having a glass transition point of 30 ° C. or higher among the components (A) to (D) is 40 to 90% by mass,
I will provide a.

  Secondly, the present invention provides an adhesive sheet having an adhesive layer made of the adhesive composition and a release material layer covering the adhesive layer.

  Thirdly, the present invention provides a coverlay film having an electrically insulating film layer and an adhesive layer made of the adhesive composition provided on the film layer.

  The adhesive composition of the present invention forms a cured product or an adhesive layer excellent in glass transition point, peel strength, solder heat resistance and processability. Therefore, since the coverlay film and adhesive sheet having this adhesive layer also have excellent characteristics, they can be suitably used and applied particularly in the field of flexible printed wiring boards and the like.

  Hereinafter, the present invention will be described in detail.

  In addition, in this specification, the glass transition point (Tg) of (A)-(F) component and the component contained depending on the case is based on DSC method, The glass transition point of the hardened | cured material of adhesive composition is This is based on the DMA method.

<Adhesive composition>
The adhesive composition of the present invention is a thermosetting adhesive composition, and is used, for example, for the production of coverlay films and adhesive sheets.

  The adhesive composition of the present invention comprises the components (A) to (F). In the present specification, the “organic solid component” is a non-volatile organic component constituting the adhesive composition of the present invention.

  Hereinafter, each component contained in the composition will be described in detail.

[(A) Phenoxy resin]
The phenoxy resin as component (A) has an epoxy group at both ends of the molecular chain, a weight average molecular weight of 10,000 or more, and a glass transition point of 40 ° C. or more.

  The weight average molecular weight is preferably 20,000 to 100,000, more preferably 30,000 to 80,000. When the molecular weight is less than 10,000, the cured product may be inferior in heat resistance and flexibility, and in the case of exceeding 100,000, the cured product may be inferior in stability. In particular, the solubility of this component in a solvent may be reduced. In addition, this molecular weight is a polystyrene conversion value by GPC.

  The glass transition point is preferably 50 to 200 ° C, more preferably 60 to 160 ° C. When the glass transition point is less than 40 ° C., the glass transition point of the cured product may be low, and when it exceeds 200 ° C., the peel strength of the cured product may be inferior.

  Further, when the phenoxy resin does not have an epoxy group at both ends of the molecular chain, the solvent resistance of the cured product, the solder heat resistance, particularly the solder heat resistance during moisture absorption is lowered.

  Examples of the phenoxy resin of this component include bisphenol A type phenoxy resin, bisphenol F type phenoxy resin, copolymerized phenoxy resin of bisphenol A type and bisphenol F type, or phenoxy resin containing a bromine atom in these molecules. Can be mentioned. As the commercially available product, for example, Epicoat 4256, Epicoat 4275, Epicoat 1256 (manufactured by Japan Epoxy Resin Co., Ltd.) and the like are listed under the trade name.

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

[(B) Epoxy resin]
The epoxy resin as the component (B) has two or more epoxy groups in one molecule and is other than the component (A). Specifically, it is usually an epoxy resin having a weight average molecular weight of less than 10,000, and may be modified with, for example, silicone, urethane, polyimide, polyamide, etc., and in the molecular skeleton, bromine atom, phosphorus atom, A sulfur atom, a nitrogen atom, etc. may be included.

  The epoxy resin preferably has 2 to 15 epoxy groups in one molecule, and more preferably 2 to 10 epoxy groups. In particular, an epoxy resin having two epoxy groups in one molecule is more excellent in flexibility and peel strength of a cured product, and an epoxy resin having three or more epoxy groups in one molecule is a cured product. The heat resistance and glass transition point of the glass are more excellent.

  Examples of the epoxy resin having two epoxy groups in one molecule include bisphenol A type epoxy resin, bisphenol F type epoxy resin, stilbene type epoxy resin, biphenyl type epoxy resin, and alicyclic epoxy resin. . As the commercial item, for example, Epicoat 828, 871, 1001, 5050, 5046 (manufactured by Japan Epoxy Resin), Sumiepoxy ELA115, 127 (manufactured by Sumitomo Chemical Co., Ltd.) and the like are listed under the trade name.

  Examples of the epoxy resin having three or more epoxy groups in one molecule include phenol novolac type epoxy resin, cresol novolac type epoxy resin, glycidylamine type epoxy resin, polyphenylmethane type epoxy resin and the like. As the commercial item, for example, Epicoat 604 (manufactured by Japan Epoxy Resin), Sumiepoxy ESCN195X, ELM120 (manufactured by Sumitomo Chemical Co., Ltd.), EOCN103S, EPPN502H, BREN-S (manufactured by Nippon Kayaku Co., Ltd.) and the like can be mentioned.

  (B) The compounding quantity of a component is 30-300 mass parts normally with respect to 100 mass parts of said (A) component, Preferably it is 50-250 mass parts, More preferably, it is 80-200 mass parts. When this blending amount satisfies such a range, the cured product has better solvent resistance, solder heat resistance, heat resistance, glass transition point, and peel strength.

  The epoxy resin of this component may be used individually by 1 type, or may use 2 or more types together.

[(C) carboxyl group-containing acrylonitrile-butadiene rubber]
The component (C) carboxyl group-containing acrylonitrile-butadiene rubber (hereinafter referred to as “NBR”) has an acrylonitrile content in this component of 20 to 50 mass% and a carboxyl group content of 0.005 to 5 mass%. It is. The carboxyl group is usually present at the end of the molecular chain. In addition, the carboxyl group-containing NBR of this component is a polymer compound having a glass transition point (Tg) of usually less than room temperature (25 ° C.).

  The acrylonitrile content in this component is preferably 25 to 45% by mass. When the acrylonitrile content is less than 20% by mass, the adhesiveness of the cured product may be insufficient, and when it exceeds 50% by mass, the electrical properties of the cured product are significantly reduced, and other components Since the compatibility with (especially the resin and the organic solvent blended in some cases) is deteriorated, the storage stability of the cured product may be inferior.

  The carboxyl group content in this component is preferably 0.001 to 1% by mass. When the carboxyl group content is less than 0.005% by mass, the reactivity of the composition decreases, so the solvent resistance of the cured product and the solder heat resistance may be inferior. The adhesion and electrical properties of the cured product may be reduced.

  Examples of the carboxyl group-containing NBR include those obtained by carboxylating a molecular chain terminal of a copolymer rubber obtained by copolymerizing acrylonitrile and butadiene, or carboxylic acid having acrylonitrile, butadiene, and a polymerizable unsaturated double bond. Examples thereof include copolymer rubbers with acid monomers. Examples of the carboxylic acid monomer include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid. Moreover, the same thing as what was illustrated as these carboxylic acid monomers can also be used for the said carboxylation.

  As the carboxyl group-containing NBR of this component, for example, ternary of acrylonitrile, a conjugated diolefin having 3 to 5 carbon atoms such as butadiene, isoprene and pentadiene and a carboxyl group-containing polymerizable monomer such as acrylic acid or methacrylic acid A copolymer rubber is mentioned. Examples of the commercially available products include Nipol 1072, 1072B, 1072J, DN631, DN601 (Nihon Zeon), Hiker CTBN (Goodrich), and the like under the trade names.

  (C) The compounding quantity of a component needs to be the quantity used as 10-60 mass% with respect to the sum total of (A)-(D) component, Preferably the quantity used as 20-50 mass%, The amount is more preferably 25 to 50% by mass. When the blending amount is less than 10% by mass, the adhesive layer (cured product) is likely to be broken or chipped when processing the coverlay film and the adhesive sheet, resulting in 60% by mass. When the amount is exceeded, the glass transition point of the cured product may be lowered.

  In a preferred embodiment, since the peel strength, flexibility, heat resistance, and glass transition point of the cured product are improved, the amount of component (C) is in addition to the above range, component (A) 100 Preferably it is 20-200 mass parts with respect to a mass part, More preferably, it is 30-150 mass parts, More preferably, it is 40-100 mass parts.

  The (C) component carboxyl group-containing NBR may be used alone or in combination of two or more.

[(D) Curing agent]
(D) The hardening | curing agent which is a component may be a well-known thing used as a hardening | curing agent of an epoxy resin. Examples of the curing agent include aliphatic amine curing agents such as diethylenetriamine, tetraethylenetetramine, and tetraethylenepentamine; alicyclic amine curing agents such as isophoronediamine; and aromatics such as diaminodiphenylmethane, diaminodiphenylsulfone, and phenylenediamine. Group amine curing agents; acid anhydride curing agents such as phthalic anhydride, pyromellitic anhydride, trimellitic anhydride, hexahydrophthalic anhydride; 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2 Imidazole compounds such as ethyl-4-methylimidazole; dicyandiamide; boron trifluoride amine complex salts, borofluorides such as tin borofluoride and zinc borofluoride; octylates such as tin octylate and zinc octylate; Preferably, the aliphatic amino acid System curing agent, aromatic amine curing agent, an imidazole compound, dicyandiamide, fluoroboric halides and octylate, particularly preferably, an aromatic amine curing agent, an imidazole compound include fluoroboric halides and octylate. Among these, it is particularly preferable to use an imidazole compound in combination with borofluoride and / or octylate.

  The blending amount of the component (D) is determined in consideration of the epoxy equivalent of the components (A) and (B), the cured state of the adhesive, the balance of the properties of the cured product, and the like. On the other hand, it is 0.1-50 mass parts normally, Preferably it is 0.5-30 mass parts, More preferably, it is 1-20 mass parts. When this blending amount satisfies such a range, the cured product has better solder heat resistance, solvent resistance, glass transition point, and electrical characteristics.

  (D) The hardening | curing agent of a component may be used individually by 1 type, or may use 2 or more types together.

[(E) inorganic filler]
The inorganic filler as component (E) is a component blended for the purpose of assisting the flame retardancy of the cured product, improving the stability of the peeled state (cohesive peeling of the adhesive), stabilizing the moisture absorption resistance, and the like. . The inorganic filler is not particularly limited as long as it is conventionally used for a coverlay film or an adhesive sheet. Examples of the inorganic filler include metal hydroxides such as aluminum hydroxide and magnesium hydroxide; metal oxides such as aluminum oxide, silicon oxide and molybdenum oxide; boric acid compounds such as zinc borate and magnesium borate. Preferred are metal hydroxides such as aluminum hydroxide and magnesium hydroxide, and boric acid compounds such as zinc borate and magnesium borate, and particularly preferred are aluminum hydroxide, magnesium hydroxide and zinc borate. It is. In order to improve the adhesion and water resistance of these inorganic fillers to the resin matrix, and to improve the heat resistance, moisture absorption resistance, etc. of the cured product, the surface of the inorganic filler is a silane coupling agent or titanate cup. It is preferably hydrophobized with a ring agent or the like.

  The amount of component (E) is usually 5 to 40% by mass, preferably 10 to 35% by mass, more preferably the total of components (A) to (D). The amount is 15 to 30% by mass. When this blending amount satisfies such a range, the peel strength, solder heat resistance, and moisture absorption resistance of the cured product become better.

  (E) The inorganic filler which is a component may be used individually by 1 type, or may use 2 or more types together.

[(F) Metal oxide vulcanizing agent]
The metal oxide vulcanizing agent as component (F) is a component for vulcanizing the carboxyl group-containing NBR and further improving the heat resistance, solder heat resistance, solvent resistance, etc. of the cured product. The average particle size of the metal oxide vulcanizing agent is not particularly limited, but is preferably 2.0 μm or less, more preferably 1.0 μm or less, and particularly preferably 0.01 to 0.5 μm. The “average particle size” means a particle size in which the mass distribution with respect to the particle size is examined and the maximum peak in mass is shown.

  Examples of the metal oxide vulcanizing agent include zinc oxide, magnesium oxide, lead oxide and the like, and zinc oxide and magnesium oxide are preferable.

  The amount of component (F) is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, and particularly preferably 1.0 to 10% by mass with respect to component (C). This is the amount. When this blending amount satisfies this range, the carboxyl group-containing NBR is sufficiently vulcanized, and the cured product has better heat resistance, solder heat resistance, solvent resistance, and peel strength.

  The (F) component metal oxide vulcanizing agent may be used alone or in combination of two or more.

[Other conditions]
-Ratio of components having a glass transition point of 30 ° C or higher With respect to the sum of components (A) to (D), the proportion of components having a glass transition point of 30 ° C or higher among the components (A) to (D) is 40. It is necessary to be -90 mass%, Preferably it is 50-80 mass%, More preferably, it is 60-80 mass%. When this ratio is less than 40% by mass, the glass transition point of the cured product may be lowered. When it exceeds 90% by mass, the adhesive layer is used when processing the coverlay film and the adhesive sheet. The (cured product) is likely to be broken or chipped.

Bromine content In a preferred embodiment of the present invention, the bromine content in the total organic solid component is preferably 12% by mass in order to improve the flame retardancy, solder heat resistance, heat resistance, etc. of the cured product. % Or more, more preferably 13 to 25% by mass, still more preferably 18 to 22% by mass.

[Other ingredients]
In addition to the components (A) to (F), the following components can be blended as necessary. Each of these other components may be used alone or in combination of two or more.

-Brominated flame retardant A brominated flame retardant may be blended in order to bring the bromine content in the composition into a preferred range. This brominated flame retardant has a melting point or softening point of preferably 80 ° C. or higher, more preferably 100 ° C. or higher, more preferably 200 to 600 ° C. Specific examples thereof include an aliphatic flame retardant, a cycloaliphatic flame retardant, an aromatic flame retardant, and the like, and preferably an aromatic flame retardant having good heat resistance and stability.

  Although the compounding quantity of a brominated flame retardant is not specifically limited, It is preferable to set it as the quantity which satisfy | fills the above-mentioned range in consideration of the bromine content rate in all the organic solid components.

Others In addition, for example, a non-brominated flame retardant, a coupling agent, an antioxidant, an ion adsorbent and the like may be added.

Organic solvent The above components (A) to (F) and components added as necessary may be used in the production of adhesive sheets and coverlay films without solvent, but are dissolved or dispersed in an organic solvent, The composition may be prepared and used as a solution or dispersion (hereinafter simply referred to as “solution”). Examples of the organic solvent include toluene, methanol, ethanol, isopropanol, acetone, dioxolane, methyl ethyl ketone (hereinafter referred to as “MEK”), and preferably toluene, dioxolane, and methyl ethyl ketone.

  The adhesive solution obtained here preferably has a concentration of all organic solid components of 20 to 45% by mass, more preferably 25 to 40% by mass, and particularly preferably 25 to 35% by mass. . When this density | concentration satisfy | fills the range of 20-45 mass%, an adhesive composition will become the thing excellent in coating property, without producing a nonuniformity at the time of coating.

  In the case of mixing the above components, the order is not particularly limited, but can be determined as appropriate in consideration of the solubility of the added components and the viscosity of the resulting adhesive solution. A pot mill, a ball mill, a homogenizer, a super mill, etc. can be used for mixing.

<Coverlay film>
-Structure As a structure of the coverlay film which has an adhesive bond layer which consists of an adhesive composition of this invention, it has an electrically insulating film layer and the adhesive bond layer provided on this film layer. Specifically, for example, a three-layer structure having an electrically insulating film layer, an adhesive layer, and a release material layer can be given. The thickness of the adhesive layer can be selected according to the purpose of use, but is usually 10 to 50 μm, preferably 15 to 35 μm, particularly preferably 15 to 25 μm in a dry state.

  Examples of the electrically insulating film constituting the electrically insulating film layer include polyimide film, PET (polyethylene terephthalate) film, polyester film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, aramid film; glass fiber, Based on aramid fiber, polyester fiber, etc., epoxy resin as a matrix, polyester resin, diallyl phthalate resin impregnated in this, film or sheet and pasted with copper foil, etc. From the viewpoints of heat resistance, dimensional stability, mechanical properties (elastic modulus, elongation, etc.), a polyimide film, a polyparabanic acid film, and a polyphenylene sulfide film are preferable, and a polyimide film is particularly preferable.

  The thickness of the electrically insulating film layer may be arbitrarily selected depending on the purpose of use, but is usually 12.5 to 75 μm, preferably 12.5 to 50 μm, particularly preferably 12.5 to 25 μm. In addition, in order to improve adhesion to the adhesive layer, clean the film surface, improve dimensional stability, etc., surface treatment such as low-temperature plasma treatment, corona discharge treatment, sandblast treatment, etc. is performed on one or both sides of this film. May be.

  Examples of the release material constituting the release material layer include polyethylene (PE) film, polypropylene (PP) film, polymethylpentene (TPX) film; PE film and PP film with silicone release material; PE resin-coated paper, PP resin Examples thereof include coated paper and TPX resin coated paper. The thickness of the release material may be an appropriate thickness as required, but is preferably 13 to 75 μm for a film and 50 to 200 μm for paper.

〔Production method〕
Next, the case where the organic solvent which is preferable embodiment is used is demonstrated as an example about the manufacturing method of the coverlay film of this invention.

  First, an adhesive solution containing an organic solvent prepared in advance is applied to one side of an electrically insulating film using a reverse roll coater, a comma coater or the like. The adhesive composition is semi-cured by removing the organic solvent in the adhesive composition by heating the film coated with this adhesive composition through an in-line dryer at 40-160 ° C for 2-20 minutes. State. Next, the application surface of the adhesive composition of the film and the release material are pressure-bonded by a heating roll under the conditions of a linear pressure of 0.2 to 20 kg / cm and a temperature of 40 to 120 ° C. to obtain a coverlay film. The release material is peeled off during use. The “semi-cured state” means a state in which the composition is dried or a state in which the curing reaction proceeds in a part thereof.

<Adhesive sheet>
-Structure As a structure of the adhesive sheet which has an adhesive bond layer which consists of an adhesive composition of this invention, it has an adhesive bond layer and the mold release material layer which coat | covers this adhesive bond layer. Specific examples include a two-layer structure having a release material layer and an adhesive layer, or a three-layer structure having a release material layer, an adhesive layer, and a release material layer. The two-layer structure and three-layer structure of the adhesive sheet may be appropriately selected depending on the processing method at the time of manufacturing the flexible printed wiring board. The thickness of the adhesive layer can be selected depending on the purpose of use, but is usually 10 to 50 μm, preferably 15 to 35 μm, particularly preferably 15 to 25 μm in a dry state.

  The release material constituting the release material layer is as described in the section of the coverlay film.

〔Production method〕
Next, the case where the organic solvent which is preferable embodiment is used is demonstrated as an example about the manufacturing method of the adhesive sheet of this invention.

  First, an adhesive solution containing an organic solvent prepared in advance is applied to one side of a release material using a reverse roll coater, a comma coater, or the like. The release agent coated with the adhesive composition is passed through an in-line dryer and heat-treated at 40 to 160 ° C. for 2 to 20 minutes to remove the organic solvent in the adhesive composition. It is set as a hardening state and it is set as the adhesive sheet of 2 layer structure. Further, another release material is pressure-bonded to the application surface of the adhesive composition of the adhesive sheet with a heating roll under the conditions of a linear pressure of 0.2 to 20 kg / cm and a temperature of 40 to 120 ° C. To do. The release material is peeled off during use.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited to these Examples. In addition, specifically, the following were used as said (A)-(F) component and another component.

<Adhesive composition components>
(A) Phenoxy resin / Epicoat 4275 (trade name) (made by Japan Epoxy Resin, weight average molecular weight: about 60,000, Tg: about 68 ° C.)
Epicoat 1256 (trade name) (made by Japan Epoxy Resin, weight average molecular weight: about 53,000, Tg: about 95 ° C.)
(B) Epoxy resin / Epicoat 604 (trade name) (made by Japan Epoxy Resin, weight average molecular weight: about 500, Tg: less than 30 ° C., 4 epoxy groups in one molecule)
Epicoat 828 (trade name) (made by Japan Epoxy Resin, weight average molecular weight: about 300, Tg: less than 30 ° C., 2 epoxy groups in one molecule)
Epicoat 1001 (trade name) (made by Japan Epoxy Resin, weight average molecular weight: about 1,000, Tg: about 70 ° C., two epoxy groups in one molecule)
Epicoat 5050 (trade name) (made by Japan Epoxy Resin, weight average molecular weight: about 800, bromine content: about 50% by mass, Tg: about 70 ° C., two epoxy groups in one molecule)
(C) Carboxyl group-containing NBR
Nipol 1072B (trade name) (manufactured by Nippon Zeon, acrylonitrile content: about 27.0% by mass, carboxyl group content: about 0.075% by mass, Tg: 0 ° C. or less)
DN631 (trade name) (manufactured by Nippon Zeon, acrylonitrile content: about 33.5% by mass, carboxyl group content: about 0.075% by mass, Tg: 0 ° C. or less)
(D) Curing agent / DDS (4,4′-diaminodiphenylsulfone, Tg: 30 ° C. or higher)
・ Dicyandiamide (Tg: about 200 ℃)
・ 2E4MZ-CN (trade name) (Shikoku Chemicals, Tg: less than 30 ° C)
-45% by weight tin borofluoride aqueous solution (Tg: 30 ° C or higher)
(E) Inorganic filler H43STE (trade name) (Showa Denko, aluminum hydroxide)
・ Kisuma 5A (trade name) (manufactured by Kyowa Chemical, magnesium hydroxide)
(F) Metal oxide vulcanizing agent and zinc oxide (average particle size: 0.5μm)
・ Magnesium oxide (average particle size: 0.5μm)
(G) Brominated flame retardant BT93 (trade name) (Ethyl, softening point: about 440 ° C., bromine content: about 66% by mass)
-PO64P (trade name) (manufactured by Great Lakes, softening point: about 200 ° C, bromine content: about 64% by mass)

<Materials used>
・ Kapton 100H (trade name) (Toray DuPont, polyimide film, thickness: 25μm)
・ Y7TF (trade name) (Made by Lintec, release paper, thickness: approx. 130 μm)
・ PET38X (trade name) (Made by Lintec, release film, thickness: approx. 38μm)
・ HTE (trade name) (Mitsui Metals, electrolytic copper foil)
RAS22S47 (trade name) (manufactured by Shin-Etsu Chemical, flexible printed wiring board, Kapton 50H / adhesive layer thickness: 13 μm / rolled copper foil 1/2 oz)

<Examples 1-9, Comparative Examples 1-4>
For each component of the adhesive composition, the types shown in Table 1 were used in the blending amounts (parts by mass) shown in the same table. First, the component (A), the component (B), and the component (D) were dissolved in MEK, stirred, and mixed to obtain a solution 1 having an organic solid component concentration of 30% by mass. Subsequently, the component (C) is separately dissolved in a MEK / toluene mixed solution (MEK: toluene = 80: 20 (mass ratio)) to be a 15 mass% solution, and the component (E) (comparative example 4) is dissolved in this solution. And (F) component (in Examples 7 to 9 and Comparative Example 2, further bromine-based flame retardant) was added, and then component (E) was sufficiently dispersed using a ball mill to obtain solution 2. It was. Thereafter, the solution 1 and the solution 2 were mixed and sufficiently stirred to obtain an adhesive solution.

  Next, this adhesive solution was applied on a polyimide film (trade name: Kapton 100H, thickness: 25 μm) using a reverse roll coater so that the thickness of the adhesive layer after drying was 25 μm. Thereafter, MEK and toluene were removed under heating and drying conditions at 140 ° C. for 10 minutes, so that the adhesive composition was in a semi-cured state. A release paper (trade name: Y7TF) is pressure-bonded to the adhesive surface of the film with the semi-cured adhesive composition using a roll laminator at a temperature of 70 ° C. and a linear pressure of 2 kg / cm. A film was prepared.

  Moreover, the adhesive sheet was produced by the process similar to preparation of a coverlay film except having changed the polyimide film into the release film (brand name: PET38X).

  About these coverlay films and adhesive sheets, physical properties were evaluated and measured according to the following evaluation and measurement methods. The results are shown in Table 1.

<Evaluation and measurement method>
(Configuration of evaluation sample)
The following sample, which was pressure-bonded while being heated at 160 ° C., 3.0 MPa for 50 minutes, was used as a sample for evaluating peel strength, solder heat resistance, and glass transition point. The release material was peeled off and used for sample preparation.
Sample 1: Adhesive layer of coverlay film and 1 oz glossy surface of HTE foil Sample 2: Both sides of adhesive sheet covered with two RAS22S47 film surfaces Sample 3: Two sides of adhesive sheet Covered with 1oz glossy surface of HTE foil

(Physical property evaluation / measurement method)
1. Peel strength (according to JIS C6471)
-Peel strength A: Sample 1 was cut to a width of 10 mm to prepare test piece 1, and for this test piece 1, HTE foil was continuously applied at a speed of 50 mm / min in the direction of 90 degrees at 25 ° C. The minimum value of the load when peeling 50 mm was measured and taken as the peel strength.
-Peel strength B: Sample 2 was cut to a width of 10 mm to produce test piece 2, and RAS22S47 was continuously 50 mm at a rate of 50 mm / min in the direction of 90 degrees under the condition of 25 ° C. The minimum value of the load when it was peeled off was measured and taken as the peel strength.

2. Solder heat resistance (according to JIS C6471)
Solder heat resistance A: Sample 1 was cut into a 25 mm square to prepare test piece 3, which was dried at 80 ° C. for 10 minutes and then floated on a solder bath for 30 seconds. Then, the external appearance of this test piece 3 was confirmed visually, and the presence or absence of a swelling, peeling, etc. was investigated. This operation was repeated while changing the temperature of the solder bath, and the maximum temperature at which the sample did not swell or peel off was measured.
Solder heat resistance B: Sample 1 was cut into a 25 mm square to prepare test piece 4, which was left at 40 ° C. and 90% RH for 1 hour, and then floated on a solder bath for 30 seconds. Thereafter, the maximum temperature was measured in the same manner as the solder heat resistance A.
Solder heat resistance C: The maximum temperature was measured in the same manner as the solder heat resistance A, except that the test piece 5 was prepared by cutting the sample 2 into 25 mm square.

3. Glass transition point (Tg)
The adhesive sheet was prepared by removing the HTE foil of Sample 3 with an aqueous ferric chloride solution, and this adhesive sheet was cut to prepare a test piece 6 (10 mm × 50 mm). Using the test piece 6, the Tg of the adhesive was measured using a viscoelasticity measuring device (trade name: RSAIII, manufactured by Rheometric Co., Ltd.) with the temperature raising condition set to 5 ° C./min. Tg was a peak (maximum value) of tan δ.

4). Workability After removing the release material from the adhesive sheet, the adhesive sheet was bent and opened in the direction of 180 degrees, and the adhesive layer was visually checked for breakage and chipping. When the adhesive layer is not broken or chipped, the processability is evaluated as good and shown as A, and when the adhesive layer is broken or chipped, the processability is evaluated as poor. B.

5). Flame resistance (according to UL94)
The coverlay film was cut into 50 mm × 200 mm to prepare a sample for flame retardancy evaluation. The sample was evaluated for flame retardancy according to the UL94VTM-0 standard. When the flame retardancy satisfied the VTM-0 standard, it was evaluated as good and indicated as A, and when it did not meet the VTM-0 standard, it was evaluated as defective and indicated as B.

Claims (6)

(A) a phenoxy resin having an epoxy group at both ends of a molecular chain, having a weight average molecular weight of 10,000 or more and a glass transition point of 40 ° C. or more;
(B) an epoxy resin other than the component (A),
(C) a carboxyl group-containing acrylonitrile-butadiene rubber having an acrylonitrile content of 20 to 50% by mass and a carboxyl group content of 0.005 to 5% by mass,
(D) a curing agent,
(E) An adhesive composition comprising an inorganic filler and (F) a metal oxide vulcanizing agent, wherein the component (C) is added to the total of the components (A) to (D). The said composition whose ratio is 10-60 mass% and whose ratio of the component whose glass transition point is 30 degreeC or more in this (A)-(D) component is 40-90 mass%.   The component (B) is 30 to 300 parts by mass, the component (C) is 20 to 200 parts by mass, and the component (D) is 0.1 to 50 parts by mass with respect to 100 parts by mass of the component (A). And the proportion of the component (E) is 5 to 40% by mass relative to the total of the components (A) to (D), and the proportion of the component (F) is relative to the component (C). The composition according to claim 1, which is 0.1 to 20% by mass.   The composition according to claim 1 or 2, wherein the component (D) contains an imidazole compound and a borofluoride and / or an octylate.   The bromine content in the total organic solid component is 12% by mass or more, The composition according to any one of claims 1 to 3.   The adhesive sheet which has the adhesive bond layer which consists of an adhesive composition as described in any one of Claims 1-4, and the mold release material layer which coat | covers this adhesive bond layer. The coverlay film which has an electrically insulating film layer and the adhesive bond layer which consists of an adhesive composition as described in any one of Claims 1-4 provided on this film layer.