JP5278179B2 - Adhesive composition, and adhesive sheet and coverlay film using the same - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention has an excellent heat resistant adhesive property, adhesive property, solder heat resistance, and workability, and particularly an adhesive composition that gives a cured product that can be suitably used for a flexible printed wiring board, and the same. The present invention relates to an adhesive sheet and a coverlay film.

  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 demands for these performances have become increasingly sophisticated. In response to such demands, flexible printed wiring boards (hereinafter referred to as FPCs) are flexible and can withstand repeated bending, so that they can be mounted three-dimensionally and densely in a narrow space. Applications are expanding as composite parts with wiring to devices, cables, and connector functions.

  An adhesive sheet is used as an adhesive material when a multilayer FPC is manufactured by bonding a plurality of FPCs or when an FPC and a reinforcing plate are bonded. This adhesive sheet has a semi-cured adhesive layer provided on one side of the release substrate, or a semi-cured adhesive layer provided on one side of the release substrate, and another release layer is provided on the adhesive layer. For example, it is required to have excellent properties such as adhesion, solder heat resistance, workability, glass transition temperature, electrical characteristics, storage stability, flame retardancy, and handling properties.

  In addition, a coverlay film in which a semi-cured adhesive layer is provided on one side of an electrically insulating base film and another release base material is bonded to the adhesive layer is used for FPC. This cover lay film is intended for FPC circuit protection and bendability improvement, such as adhesion, solder heat resistance, workability, glass transition temperature, electrical properties, storability, handling properties, etc. It is required to have excellent characteristics.

  With the recent reduction in size, weight and density of electronic devices, multilayer FPCs are increasingly used as FPCs built into electronic devices. Multi-layer FPCs must be equipped with reinforcing plates, electromagnetic wave shields, etc., and many mounting parts must be mounted. In addition, multilayer FPCs are often placed in harsh usage environments. Therefore, the multilayer FPC tends to repeatedly receive a thermal history and is often exposed for a long time under high temperature and high humidity. Therefore, the adhesive sheet and coverlay film used for such FPC are required to have excellent heat-resistant adhesiveness and solder heat resistance against the above-described thermal cycle and severe high temperature and high humidity conditions. However, particularly with respect to heat-resistant adhesiveness, the conventional adhesive sheet and coverlay film are not sufficiently reliable at present.

  The main cause of the decrease in heat-resistant adhesion is a synthetic rubber having an unsaturated bond in the molecular chain (for example, acrylonitrile-butadiene rubber, which is contained in an adhesive sheet and a coverlay film and expresses these adhesive forces) Etc.) is considered to be due to thermal oxidative degradation. In order to prevent such thermal oxidative deterioration of the synthetic rubber and obtain excellent heat-resistant adhesion, acrylic resin, polyester resin, polyimide resin, phenol resin, epoxy resin, phenoxy resin, acrylonitrile-butadiene rubber, or these two Although an adhesive sheet and a coverlay film provided with an adhesive layer composed of a combination of more than one species have been proposed (for example, Patent Documents 1 to 4), all have heat resistant adhesiveness, adhesiveness, solder heat resistance and workability at the same time. It is not enough to satisfy.

  For the same purpose, adhesive sheets and coverlay films to which various conventional deterioration-preventing agents such as phenols and amines have been proposed have been proposed and are effective under relatively mild temperature conditions. Yes. However, as described above, in recent years, the environment in which FPC is used becomes more severe, and it is often used under high temperature conditions of 80 ° C. or higher. Under such a high temperature condition, the above-mentioned various conventional deterioration preventing agents are sufficiently prevented from vaporizing and disappearing, so that even if these various deterioration preventing agents are added, the thermal oxidation deterioration of the synthetic rubber is sufficiently prevented. Is difficult. Therefore, the above-described conventional adhesive sheet and cover lay film containing synthetic rubber to which various deterioration inhibitors are added do not sufficiently satisfy the heat-resistant adhesive property, the adhesive property, the solder heat resistance and the workability at the same time.

JP 2001-291964 A JP 2004-256682 A JP 2004-323811 A JP 2007-045882

  An object of the present invention is to provide an adhesive composition having excellent heat-resistant adhesiveness, adhesiveness, soldering heat resistance and workability, and particularly a cured product that can be suitably used for FPC, and the composition. It is to provide an adhesive sheet and a coverlay film.

  As a result of intensive studies, the present inventor added a sulfur-containing hindered phenol-based degradation inhibitor represented by the following general formula (1) to the adhesive composition, whereby a cured product of the adhesive composition, And it discovered that the heat-resistant adhesiveness of the adhesive sheet and coverlay film using this composition can be improved very effectively.

That is, in order to solve the above problems, the present invention firstly
(A) epoxy resin,
(B) carboxyl group-containing acrylonitrile-butadiene rubber,
(C) curing agent,
(D) inorganic filler, and (E) the following general formula (1):

（式中、R₁およびR₂は独立に水素原子または炭素原子数1〜20のアルキル基であり、R₃は水素原子または炭素原子数1〜5のアルキル基である。）
で表される硫黄含有ヒンダードフェノール系劣化防止剤
を含有してなる接着剤組成物であって、前記（E）成分の配合量が前記（B）成分に対して1〜30質量％である前記接着剤組成物を提供する。

(In the formula, R ₁ and R ₂ are independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R ₃ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.)
It is an adhesive composition containing a sulfur-containing hindered phenol-based degradation inhibitor represented by the formula (E), and the blending amount of the component (E) is 1 to 30% by mass with respect to the component (B). The adhesive composition is provided.

  Secondly, the present invention provides an adhesive sheet having a release substrate and an adhesive layer made of the composition provided on the release substrate.

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

  The adhesive composition of the present invention provides a cured product having excellent heat-resistant adhesiveness, adhesiveness, solder heat resistance and workability. Therefore, the adhesive sheet and cover lay film produced using this composition also have excellent heat resistant adhesiveness, adhesiveness, solder heat resistance and workability, and therefore can be suitably used and applied particularly in the field of FPC and the like.

  Hereinafter, the present invention will be described in detail.

<Adhesive composition>
The adhesive composition of the present invention is a thermosetting adhesive composition comprising the above components (A) to (E), and further contains optional components such as a solvent as necessary. Also good. In addition, when the adhesive composition of this invention contains a solvent as an arbitrary component, a solvent is not normally contained in an organic resin component.

  The method of use and the form of use of the composition of the present invention 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 in a layered manner. Used as a composition for adhering a kimono. The adherend is not particularly limited, and examples thereof include a combination of a copper foil and an electrically insulating film used for a cover lay film described later. Moreover, the composition of this invention is used also for manufacture of an adhesive sheet, a coverlay film, etc., for example.

  Hereinafter, the above-mentioned components (A) to (E), other optional components, and the method for preparing the adhesive composition of the present invention will be described in detail.

[(A) Epoxy resin]
The epoxy resin as component (A) is usually preferably an epoxy resin having a weight average molecular weight of less than 10,000, and specifically limited as long as it has two or three or more epoxy groups in one molecule. Instead, it may be modified with silicone, urethane, polyimide, polyamide or the like. Also, brominated epoxy resins can be used to impart flame retardancy. Furthermore, a phosphorus atom, a sulfur atom, a nitrogen atom or the like may be included in the molecular skeleton.

  Among such epoxy resins, as an epoxy resin having two epoxy groups in one molecule, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, stilbene type epoxy resin, alicyclic epoxy resin, biphenyl Type epoxy resin and the like. In a commercial item, for example, as a non-brominated epoxy resin, it is a brand name, jER828, 871, 1001, 1256 (made by Japan Epoxy Resin), Sumiepoxy ELA115, 127 (made by Sumitomo Chemical), NC-3000H. (Manufactured by Nippon Kayaku Co., Ltd.) and the like, and examples of brominated epoxy include jER5050, 5048, 5046 (manufactured by Japan Epoxy Resin) and the like under the trade names.

  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. Examples of commercially available products include non-brominated epoxy resins such as jER604 (made by Japan Epoxy Resin), Sumiepoxy ESCN195X, ELM120 (made by Sumitomo Chemical), EOCN103S, EPPN502H (made by Nippon Kayaku), and the like. Examples of brominated epoxy resins include BREN-S (manufactured by Nippon Kayaku Co., Ltd.) under the trade name.

  An epoxy resin having two epoxy groups in one molecule is effective in improving the flexibility and adhesiveness of the cured product, and an epoxy resin having three or more epoxy groups in one molecule has a heat resistance of the cured product. It is effective in improving the property and glass transition temperature. Epoxy resins are used in consideration of these characteristics, but may be used alone or in combination of two or more.

[(B) Carboxyl group-containing acrylonitrile-butadiene rubber]
The component (B) carboxyl group-containing acrylonitrile-butadiene rubber (hereinafter referred to as “carboxyl group-containing NBR”) preferably has an acrylonitrile residue content in this component of 20 to 50% by mass, more preferably 25 to 45%. The carboxyl group content is preferably 0.001 to 10 mass%, more preferably 0.005 to 5 mass%. When the acrylonitrile residue content is 20 to 50% by mass, the compatibility between the component (B) and other components (particularly, the epoxy resin of the component (A) and the solvent to be blended in some cases) is particularly good. Therefore, a cured product excellent in storage stability can be easily obtained, and the adhesiveness and electrical properties of the cured product are likely to be good. When the carboxyl group content is 0.001 to 10% by mass, the reactivity of the resulting composition is easily maintained in an appropriate range, so that a cured product having excellent solvent resistance and solder heat resistance can be easily obtained. Moreover, the adhesiveness and electrical properties of the cured product tend to be good.

  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, and carboxylic acid monomers having a polymerizable unsaturated double bond with acrylonitrile, butadiene, and the like. These terpolymer rubbers are listed. Examples of the carboxylic acid monomer include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid. For the carboxylation, those exemplified as these carboxylic acid monomers can be used. In addition, the carboxyl group-containing NBR is a crosslinked rubber that is partially crosslinked by further adding a crosslinkable monomer in a ternary copolymerization step of acrylonitrile, butadiene, and a carboxylic acid monomer having a polymerizable unsaturated double bond. If necessary, it may be a crosslinked rubber that is made into particles after crosslinking.

  Examples of the terpolymer rubber include 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. Examples of commercially available products include Nipol 1072, 1072B, 1072J, DN631, DN631, and DN601 (manufactured by Nippon Zeon), Hiker CTBN (manufactured by Goodrich). XER-32 (manufactured by JSR) and the like. Moreover, as said crosslinked rubber, XER-91 (made by JSR) etc. are mentioned by a brand name, for example.

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

  (B) Although the compounding quantity of carboxyl group-containing NBR which is a component is not restrict | limited, Preferably it is 5-200 mass parts with respect to 100 mass parts of (A) component, More preferably, it is 10-100 mass parts. is there. When the blended amount is in the range of 5 to 200 parts by mass, the adhesive layer (cured product) is not easily broken during the production of the adhesive sheet and coverlay film, and defects such as chipping are unlikely to occur, and the glass transition temperature of the cured product. Is difficult to decrease.

[(C) Curing agent]
(C) The hardening agent which is a component may be a well-known thing used as a hardening | curing agent of an epoxy resin. Examples of such curing agents include aliphatic amine curing agents such as diethylenetriamine, tetraethylenetetramine, and tetraethylenepentamine; alicyclic amine curing agents such as isophoronediamine; diaminodiphenylmethane, diaminodiphenylsulfone, and phenylenediamine. Aromatic amine curing agent; phenolic resin such as resol type phenolic resin, novolac type phenolic resin; acid anhydride type curing agent such as phthalic anhydride, pyromellitic anhydride, trimellitic anhydride, hexahydrophthalic anhydride; 2-methylimidazole Imidazole compounds such as 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole; dicyandiamide; boron trifluoride amine complex salts, borofluorides such as tin borofluoride and zinc borofluoride Tin octylate, Examples include octylates such as zinc octylate, preferably aliphatic amine-based curing agents, aromatic amine-based curing agents, phenol resins, imidazole compounds, borofluorides, dicyandiamide, and octylates. Are aromatic amine curing agents, phenol resins, imidazole compounds, and borofluorides.

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

  (C) The compounding quantity of the hardening | curing agent which is a component may be an effective amount as a hardening | curing agent, Although it does not restrict | limit, Preferably it is 0.1-80 mass parts with respect to 100 mass parts of (A) component, More preferably Is 0.5 to 40 parts by mass. When the blending amount is in the range of 0.1 to 80 parts by mass, the obtained cured product has better heat resistance, solder heat resistance, solvent resistance, glass transition temperature, and electrical characteristics.

[(D) inorganic filler]
The inorganic filler (D) is a component formulated 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, etc. is there. 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 boric acid. Zinc. 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. Hydrophobic treatment with a system coupling agent or the like is preferred.

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

  (D) Although the compounding quantity of the inorganic filler which is a component is not restrict | limited in particular, Preferably it is 5-100 mass% with respect to the total amount of (A)-(C) component, More preferably, 10-50 % By mass. When the blending amount is in the range of 5 to 100% by mass, the obtained cured product has better heat resistance adhesion, solder heat resistance, and moisture absorption resistance.

[(E) Sulfur-containing hindered phenol-based degradation inhibitor represented by general formula (1)]
The component (E) has the following general formula (1):

（式中、R₁およびR₂は独立に水素原子または炭素原子数1〜20のアルキル基であり、R₃は水素原子または炭素原子数1〜5のアルキル基である。）
で表される硫黄含有ヒンダードフェノール系劣化防止剤であり、（B）成分であるカルボキシル基含有NBRの熱酸化劣化を防止する。そこで、（E）成分は、本発明の接着剤組成物の硬化物の耐熱接着性を向上させることを目的として配合される。

(In the formula, R ₁ and R ₂ are independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R ₃ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.)
It is a sulfur-containing hindered phenol-based degradation inhibitor represented by the formula, and prevents thermal oxidation degradation of the carboxyl group-containing NBR that is the component (B). Then, (E) component is mix | blended for the purpose of improving the heat-resistant adhesiveness of the hardened | cured material of the adhesive composition of this invention.

R ₁ and R ₂ in the general formula (1) may be the same or different, and are independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and an alkyl group having 1 to 20 carbon atoms. In some cases, it may be linear or branched, but is preferably a linear alkyl group having 5 to 15 carbon atoms. Examples of R ₁ and R ₂ that are alkyl groups having 1 to 20 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, and n-heptyl group. Group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group A linear alkyl group such as a group, n-octadecyl group, n-nonadecyl group or n-icosyl group; a branched alkyl group such as isopropyl group, sec-butyl group, t-butyl group or 2-ethylhexyl group. Can be mentioned. Among them, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group Group and n-pentadecyl group are preferable, and n-octyl group, n-nonyl group, n-decyl group, n-undecyl group and n-dodecyl group are particularly preferable.

R ₃ in the general formula (1) is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and when it is an alkyl group having 1 to 5 carbon atoms, it is either linear or branched There may be. Examples of R ₃ which is an alkyl group having 1 to 5 carbon atoms include linear alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group; an isopropyl group, Examples thereof include branched alkyl groups such as a sec-butyl group and a t-butyl group. Of these, a methyl group, an ethyl group, and an n-propyl group are preferable, and a methyl group is particularly preferable.

  Examples of commercially available sulfur-containing hindered phenol-based degradation inhibitors for component (E) include, for example, IRGANOX 1520L (Ciba, 4,6-bis (octylthiomethyl) -o-cresol), 1726 (Ciba, 4,6-bis (dodecylthiomethyl) -o-cresol) and the like.

  The sulfur-containing hindered phenol-based degradation inhibitor (E) may be used alone or in combination of two or more.

  The compounding amount of the sulfur-containing hindered phenol-based degradation inhibitor as the component (E) is usually 1 to 30% by mass, preferably 1 to 25% by mass with respect to the carboxyl group-containing NBR as the component (B). %, More preferably 5 to 20% by mass. When the blending amount is in the range of 1 to 30% by mass, the cured product has better heat-resistant adhesiveness and solder heat resistance.

[Other optional ingredients]
In addition to the above components (A) to (E), if necessary, a solvent, a flame retardant, a coupling agent, as long as it does not deteriorate the properties of the adhesive composition and the adhesive sheet and coverlay film using the same. You may add arbitrary components, such as an ion supplement.

  Examples of the solvent used in the adhesive composition of the present invention include methyl ethyl ketone (MEK), toluene, methanol, ethanol, isopropanol, acetone, N, N-dimethylformamide, cyclohexanone, N-methyl 2-pyrrolidone, and dioxolane. Among them, MEK, toluene, N, N-dimethylformamide, and cyclohexanone are preferable. These solvents may be used alone or in combination of two or more.

  In a solution in which components other than the solvent of the adhesive composition are dissolved in a solvent (hereinafter sometimes referred to as “adhesive composition solution”), the solid content may be 20 to 50% by mass, and more preferably 25 to 40% by mass. If the solid content concentration is less than 20% by mass, there is a high risk of unevenness in thickness when the adhesive composition solution is applied. If the solid content concentration exceeds 50% by mass, the adhesive composition solution has a high viscosity, so that the coating property is deteriorated. Problems arise. Note that. Solid content refers to a substance that does not volatilize after leaving a 35% by weight solution obtained by dissolving the adhesive composition in methyl ethyl ketone as a solvent at a depth of 25 μm and leaving it at 120 ° C. for 10 minutes. Specifically, it is mainly the components (A) to (E), and may include a part of optional components added as necessary.

(Preparation of composition)
The adhesive composition of the present invention can be prepared by mixing the components (A) to (E) and optional components added as necessary according to a conventional method. The order in which the components (A) to (E) and the optional components are mixed is not particularly limited, and is appropriately determined in consideration of the solubility of the added components and the viscosity of the resulting adhesive composition solution. A pot mill, a ball mill, a homogenizer, a super mill, etc. can be used for mixing.

<Adhesive sheet>
〔Constitution〕
The adhesive sheet which has the adhesive bond layer which consists of an adhesive composition of this invention has a mold release base material and this adhesive bond layer provided on this mold release base material. Specifically, for example, a two-layer structure having a release substrate and an adhesive layer, or a three-layer structure having an adhesive layer and a release substrate provided on both sides of the adhesive layer, etc. Can be mentioned. Any one of a two-layer structure and a three-layer structure may be appropriately selected according to a processing method at the time of manufacturing an FPC. The thickness of the adhesive layer can be selected depending on the purpose of use, but is preferably 10 to 50 μm, more preferably 15 to 35 μm, and particularly preferably 15 to 25 μm in a dry state.

  The release substrate is not particularly limited as long as it is a film-like material that can be peeled off from the adhesive layer without impairing the form of the adhesive layer, if necessary. Examples of mold release substrates include polyethylene (PE) films, polypropylene (PP) films, polymethylpentene (TPX) films, PE films with silicone mold release substrates, and PP films with silicone mold release substrates. Film: Release paper such as PE resin-coated paper, PP resin-coated paper, TPX resin-coated paper, and the like. The thickness of the release substrate may be appropriately selected as necessary. For example, when the release substrate is a release film, the thickness of the substrate is preferably 13 to 75 μm, When the release substrate is a release paper, the thickness of the substrate is preferably 50 to 200 μm.

〔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 composition solution containing an organic solvent prepared in advance is applied to one side of a release substrate using a reverse roll coater, a comma coater, or the like. The release substrate coated with this adhesive composition solution is passed through an in-line dryer and heated at 40 to 160 ° C. for 2 to 20 minutes to remove the organic solvent in the adhesive composition solution. The composition is made into a semi-cured state to form an adhesive sheet having a two-layer structure. Further, another release substrate is bonded to the application surface of the adhesive composition of the adhesive sheet 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. A sheet. The release substrate is peeled off when the adhesive sheet is used. 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.

<Coverlay film>
〔Constitution〕
The coverlay film having an adhesive layer made of the adhesive composition of the present invention has an electrically insulating film and the adhesive layer provided on the electrically insulating film. Specifically, for example, a three-layer structure having an electrically insulating film, an adhesive layer, and a release substrate provided on the adhesive layer can be given. The thickness of the adhesive layer can be selected depending on the purpose of use, but is preferably 10 to 50 μm, more preferably 15 to 35 μm, and particularly preferably 15 to 25 μm in a dry state.

  Examples of electrically insulating films include polyimide film, PET (polyethylene terephthalate) film, polyester film, polyparabanic acid film, polyetheretherketone film, polyphenylene sulfide film, aramid film; glass fiber, aramid fiber, polyester fiber, etc. And impregnated with a matrix epoxy resin, polyester resin, diallyl phthalate resin, or a combination of two or more of these, and film-like or sheet-like bonded with copper foil. From the viewpoints of properties, 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 this electrically insulating film may be selected depending on the purpose of use, but is preferably 12.5 to 75 μm, more preferably 12.5 to 50 μm, and 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.
The mold release substrate is as described in the section of the adhesive sheet.

〔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 composition 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 film coated with the adhesive composition solution is passed through an in-line drier and heated at 40 to 160 ° C. for 2 to 20 minutes to remove the organic solvent in the adhesive composition solution, whereby the adhesive composition Is in a semi-cured state. Next, the coated surface of the adhesive composition of the film and the release substrate are pressure-bonded 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 obtain a coverlay film. The release substrate is peeled off when the coverlay film is used.

  The adhesive sheet and coverlay film of the present invention can be used to produce an FPC according to a conventional method. In the FPC manufacturing process, the semi-cured adhesive layer may be completely cured each time one or both of the adhesive sheet and the coverlay film are bonded together, or after the final FPC configuration is assembled, It may be cured. The adhesive layer in the semi-cured state in the adhesive sheet and the coverlay film of the present invention can be completely cured by heating at 140 to 180 ° C. for 40 to 120 minutes under a pressure of 1 to 5 MPa, for example.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, these Examples do not limit this invention at all.

<Adhesive composition components>
Specifically, the following components (A) to (E) and other optional components used in Examples and Comparative Examples were used.

(A) Epoxy resin jER604 (trade name) (manufactured by Japan Epoxy Resin, weight average molecular weight: about 500, epoxy equivalent: about 109 g / eq)
・ JER828 (trade name) (manufactured by Japan Epoxy Resin, weight average molecular weight: about 300, epoxy equivalent: about 189 g / eq)
・ JER1001 (trade name) (manufactured by Japan Epoxy Resin, weight average molecular weight: about 1,000, epoxy equivalent: about 475 g / eq)
・ JER5050 (trade name) (made by Japan Epoxy Resin, weight average molecular weight: about 800, epoxy equivalent: about 395 g / eq, bromine content: about 50% by mass)

(B) Carboxyl group-containing NBR
・ Nipol 1072B (trade name) (Nippon Zeon)
・ XER-32 (trade name) (manufactured by JSR)
・ XER-91 (trade name) (manufactured by JSR)

(C) Curing agent DDS (4,4′-diaminodiphenyl sulfone, molecular weight: about 248, active hydrogen equivalent: about 62 g / eq)
・ Phenolite J-325 (trade name) (manufactured by Dainippon Ink and Chemicals, resol type phenolic resin, active hydrogen equivalent of about 65 g / eq)
-45% by mass aqueous solution of tin borofluoride (molecular weight of tin borofluoride: about 292)
・ 2E4MZ-CN (trade name) (manufactured by Shikoku Chemicals, imidazole compound)

(D) Inorganic filler-H43STE (trade name) (Showa Denko, aluminum hydroxide)
・ Kisuma 5A (trade name) (manufactured by Kyowa Chemical, magnesium hydroxide)

(E) Sulfur-containing hindered phenol-based degradation inhibitor represented by general formula (1) ・ IRGANOX 1520L (trade name) (manufactured by Ciba)
・ IRGANOX 1726 (trade name) (Ciba)

Other optional components ・ Nipol 1043 (trade name) (Nippon Zeon, carboxyl group-free NBR)
-Baymac G (trade name) (Mitsui DuPont Polychemicals, carboxyl group-containing ethylene-acrylic rubber)
・ IRGANOX1135 (trade name) (Ciba, hindered phenol-based degradation inhibitor that does not contain sulfur)
・ IRGANOX565 (trade name) (made by Ciba, a sulfur-containing hindered phenol-based degradation inhibitor not represented by the general formula (1))

<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 Co., Ltd., flexible printed wiring board, Kapton 50H / adhesive layer thickness: 13 μm / rolled copper foil 1/2 oz (oz))

<Examples 1 to 5 and Comparative Examples 1 to 9>
Each component of the adhesive composition was mixed at a blending ratio (parts by mass) shown in Table 1 to prepare a mixture. This mixture was dissolved in a MEK / toluene mixed solvent (MEK: toluene = 80: 20 (mass ratio)) and stirred sufficiently using a ball mill to be uniform, and the total concentration of solids was 35% by mass. An adhesive composition solution was prepared.

  Next, the adhesive composition solution was applied on a release film (trade name: PET38X) 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 120 ° C. for 10 minutes to make the adhesive composition semi-cured. The release surface on the release paper (trade name: Y7TF) is aligned with the semi-cured adhesive surface on the film with the semi-cured adhesive composition, and the temperature is 70 ° C. and the linear pressure is 2 kg / cm. Under the conditions described above, pressure bonding was performed using a roll laminator to prepare an adhesive sheet.

  Moreover, the coverlay film was produced by the process similar to preparation of an adhesive sheet except having changed the release film into the polyimide film (Brand name: Kapton 100H, thickness: 25 micrometers).

  About these adhesive sheets and coverlay films, 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)
Samples 1 and 2 below were prepared by thermocompression bonding under press processing conditions at 160 ° C., 5.0 MPa, and used as evaluation samples for peel strength, solder heat resistance, and heat peel strength. A sample was prepared after the release substrate was peeled off.
Sample 1: Adhesive layer on both sides of the adhesive layer covered with one RAS22S47 film surface Sample 2: Adhesive layer of coverlay film and 1 oz (1 oz) glossy HTE foil

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

2. Solder heat resistance (according to JIS C6471)
Normal solder heat resistance: Sample 2 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, this test piece 3 was taken out from the solder bath, the external appearance of this test piece 3 was confirmed visually, and the presence or absence of 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.
Moisture-absorbing solder heat resistance: Sample 2 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. The remaining operations were performed in the same manner as described in the section of normal solder heat resistance, and the maximum temperature was measured.

3. Heat-resistant peel strength Sample 2 was cut to a width of 10 mm to prepare test piece 5, and this test piece 5 was left at 100 ° C. and 90% RH for 1000 hours, and then the HTE foil was 90 ° C. at 25 ° C. The minimum value of the load when 50 mm was peeled continuously at a speed of 50 mm / min in the direction was measured to obtain the heat-resistant peel strength.

4). Workability The release substrate was removed from the adhesive sheet, the remaining adhesive layer was folded in the direction of 180 degrees and opened, and the adhesive layer was visually checked for breakage and chipping. If no breakage or chipping is observed in the adhesive layer, the processability is evaluated as good (indicated by ○ in Table 1). If at least one of the folding or chipping is observed in the adhesive layer, the workability is poor. (Indicated by x in Table 1).

<Evaluation results>
The compositions prepared in Examples 1 to 5 satisfied the requirements of the present invention, and had excellent adhesion, solder heat resistance, heat resistance adhesion and workability.
On the other hand, the compositions prepared in Comparative Examples 1 to 9 do not satisfy the requirements of the present invention, and at least one characteristic of adhesiveness, solder heat resistance, heat resistant adhesiveness and workability is prepared in the examples. It was inferior to what I did.

Claims (6)

(A) epoxy resin,
(B) carboxyl group-containing acrylonitrile-butadiene rubber,
(C) curing agent,
(D) inorganic filler, and (E) the following general formula (1):

(In the formula, R ₁ and R ₂ are independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R ₃ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.)
It is an adhesive composition containing a sulfur-containing hindered phenol-based degradation inhibitor represented by the formula (E), and the blending amount of the component (E) is 1 to 30% by mass with respect to the component (B). The adhesive composition.   The composition according to claim 1, wherein the adherends are bonded by being sandwiched between two adherends.   The adhesive sheet which has a mold release base material and the adhesive bond layer which consists of a composition of Claim 1 provided on this mold release base material.   The coverlay film which has an electrically insulating film and the contact bonding layer which consists of a composition of Claim 1 provided on this electrically insulating film.   The coverlay film according to claim 4, wherein the electrically insulating film is a polyimide film.   The coverlay film according to claim 4 or 5, further comprising a release substrate provided on the adhesive layer.