JP2008222906A - Adhesive composition for flexible wiring board, cover-lay, adhesive film, flexible copper-clad laminate, flexible wiring board and wiring board with stiffening plate each using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition for a flexible wiring board which can improve the high temperature sliding and bending performance of the board when it is used for producing a flexible wiring board and also has good adhesion, heat resistance, and flame retardancy. <P>SOLUTION: The adhesive composition comprises (A) a polyepoxide compound, (B) an curing agent for an epoxy compound, and (C) a styrene/butadiene/methyl methacrylate triblock copolymer as essential components. The size of the structure of the component (C) is 60-5,000 nm. The component (C) is contained in an amount of 1-30 pts.wt. based on 100 pts.wt. of the component (A). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an adhesive composition for a flexible wiring board, and a cover lay, an adhesive film, a flexible copper-clad laminate, a flexible wiring board, and a wiring board with a reinforcing plate using the same.

  In recent years, as electronic devices have become smaller, lighter, and more functional, fine pitches and miniaturization have rapidly progressed in flexible wiring boards and package / module substrates used in such devices. Furthermore, with the growing concern about global environmental issues and human safety, the demand for less harmful and higher safety, such as lead-free soldering and the use of non-halogen flame retardants, has increased. ing.

  For these reasons, adhesive compositions used for flexible wiring boards are also required to have excellent heat resistance and high-density mounting, and there are demands for solder heat resistance and copper foil peel strength. Increasing further. In addition, since flexible wiring boards are forced to be used under high temperature conditions due to heat generation problems of equipment and the like, improvement in high temperature reliability is required. In particular, since flexible wiring boards are used under sliding, there is an urgent need to improve sliding bending characteristics at high temperatures.

For improving the sliding flexibility of such an adhesive composition, use of, for example, an acrylic-modified epoxy resin or a rubber-modified epoxy resin has been studied. In addition, such an adhesive composition is still insufficient in brittleness. For example, a mixture of a brominated phenoxy resin and an epoxy resin is mixed with an amine curing agent and an acid anhydride curing agent as a curing agent. Further, it has been studied to improve the high-temperature sliding flexibility by further mixing a silane coupling agent (for example, see Patent Document 1).
JP 2001-098243 A

  As described above, regarding the adhesive composition used for the flexible wiring board, various composition modification proposals have been made in order to improve the sliding flexibility, particularly the high temperature sliding flexibility. However, the conventional adhesive composition has not yet obtained sufficient characteristics with respect to high temperature sliding flexibility.

  The present invention has been made to solve the above-described problems, and is excellent in high-temperature sliding flexibility, good in adhesiveness, heat resistance and flame retardancy, and highly reliable and flexible. It is an object to provide an adhesive composition for a wiring board, and a coverlay, an adhesive film, a flexible copper-clad laminate, a flexible wiring board, and a wiring board with a reinforcing plate using the same.

  The adhesive composition for flexible wiring boards of the present invention (hereinafter also simply referred to as an adhesive composition) includes (A) a polyepoxide compound, (B) a curing agent for epoxy, and (C) styrene / butadiene / methyl methacrylate. An adhesive composition comprising a triblock copolymer as an essential component, wherein the dimension of the structure of the styrene / butadiene / methyl methacrylate triblock copolymer of the component (C) is 60 nm or more and 5000 nm or less, and the component (A) The styrene / butadiene / methyl methacrylate triblock copolymer of component (C) is contained in an amount of 1 to 30 parts by weight based on 100 parts by weight of the polyepoxide compound.

In the adhesive composition of the present invention, each block in the styrene / butadiene / methyl methacrylate triblock copolymer as the component (C) is preferably as shown in the following (1) to (3).
(1) A styrene block having a number average molecular weight of 20,000 g / mol to 200,000 g / mol and having a content in the styrene / butadiene / methyl methacrylate triblock copolymer of 30 wt% to 60 wt%.
(2) A butadiene block having a number average molecular weight of 10,000 g / mol to 200,000 g / mol and having a content in the styrene / butadiene / methyl methacrylate triblock copolymer of 10 wt% to 40 wt%.
(3) A methyl methacrylate block having a number average molecular weight of 20,000 g / mol to 200,000 g / mol, and a content in the styrene / butadiene / methyl methacrylate triblock copolymer of 5 wt% to 40 wt%.

  The coverlay of this invention has a polyimide film and the adhesive bond layer formed using the adhesive composition of the said invention on the surface of the said polyimide film, It is characterized by the above-mentioned. The adhesive film of the present invention is characterized in that the adhesive composition of the present invention is formed into a film. Furthermore, the flexible copper clad laminated board of this invention has a polyimide film and the copper foil joined by the adhesive composition of this invention to the at least one main surface of the said polyimide film, It is characterized by the above-mentioned.

  The flexible wiring board of the present invention is characterized in that a circuit is formed on the copper foil in the flexible copper-clad laminate of the present invention. In the flexible wiring board of the present invention, one obtained by bonding the coverlay of the present invention on the circuit is preferable. Moreover, the wiring board with a reinforcing board of the present invention is characterized in that the flexible wiring board of the present invention and the reinforcing board are bonded together via the adhesive film of the present invention.

  According to the present invention, the adhesive composition for flexible wiring boards contains a styrene / butadiene / methyl methacrylate triblock copolymer having a specific dimension at a specific ratio, so that a high-temperature slip such as a flexible wiring board using the same can be obtained. The dynamic flexibility can be made extremely excellent, and the adhesiveness, heat resistance and flame retardancy can also be made good.

  Hereinafter, the present invention will be described in detail. The adhesive composition of the present invention contains (A) a polyepoxide compound, (B) a curing agent for epoxy, and (C) a styrene / butadiene / methyl methacrylate triblock copolymer as essential components. The adhesive composition of the present invention is characterized in that the dimension of the structure of the styrene / butadiene / methyl methacrylate triblock copolymer as the component (C) is 60 nm or more and 5000 nm or less. In the adhesive composition of the present invention, the styrene / butadiene / methyl methacrylate triblock copolymer as the component (C) is 1 part by weight or more and 30 parts by weight with respect to 100 parts by weight of the polyepoxide compound as the component (A). It is characterized by being contained by weight part or less.

  As the polyepoxide compound of component (A), an epoxy resin having two or more epoxy groups in one molecule, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, glycidyl ether type epoxy resin, fat Examples thereof include cyclic epoxy resins, heterocyclic epoxy resins, glycidyl ether-based modified epoxy resins and bromines thereof, and these can be used alone or in admixture of two or more. Further, by modifying with siloxane and phosphorus compound, it is possible to impart flame retardancy without halogen.

  As the epoxy curing agent for component (B), general epoxy curing agents can be used, such as dicyandiamide (DICY) and its derivatives, novolac-type phenol resins, amino-modified novolac-type phenol resins, and polyvinylphenol resins. , Organic acid hydrazide, diaminomaleonitrile and its derivatives, melamine and its derivatives, amine imide, polyamine salt, molecular sieve, amine, acid anhydride, polyamide, imidazole, etc., these may be used alone or in combination of two or more. Can be used.

  The component (C), a styrene / butadiene / methyl methacrylate triblock copolymer (hereinafter also simply referred to as a triblock copolymer) is composed of a styrene block, a butadiene block and a methyl methacrylate block, and is mainly used for high temperature sliding of the adhesive composition. It is added to improve dynamic flexibility.

  As such a triblock copolymer of the component (C), those having a structure dimension of 60 nm or more and 5000 nm or less are used. Further, such a triblock copolymer of the component (C) is contained in a range of 1 part by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the polyepoxide compound of the component (A).

  That is, when the structure size of the triblock copolymer is less than 60 nm or more than 5000 nm, it is difficult to improve the high temperature sliding flexibility when used in the production of flexible wiring boards, etc. Other characteristics such as adhesiveness, heat resistance, and flame retardancy may be deteriorated. When the content of the triblock copolymer is less than 1 part by weight relative to 100 parts by weight of the polyepoxide compound as the component (A), the effect of adding the triblock copolymer is small, and the high temperature sliding flexibility of the adhesive composition is reduced. It becomes difficult to improve. In addition, when the content of the triblock copolymer exceeds 30 parts by weight with respect to 100 parts by weight of the polyepoxide compound as the component (A), characteristics other than high-temperature sliding bendability, that is, adhesiveness, heat resistance, flame retardancy, etc. Various characteristics may be deteriorated. The content of the triblock copolymer is more preferably 1 part by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the polyepoxide compound as the component (A).

As the triblock copolymer of component (C), specifically, each block, that is, a styrene block, a butadiene block, and a methyl methacrylate block are preferably those shown in the following (1) to (3), respectively.
(1) A styrene block having a number average molecular weight of from 20,000 g / mol to 200,000 g / mol and having a content in the styrene / butadiene / methyl methacrylate triblock copolymer of from 30% by weight to 60% by weight.
(2) A butadiene block having a number average molecular weight of 10,000 g / mol to 200,000 g / mol and having a content in the styrene / butadiene / methyl methacrylate triblock copolymer of 10 wt% to 40 wt%.
(3) A methyl methacrylate block having a number average molecular weight of 20,000 g / mol to 200,000 g / mol and having a content in the styrene / butadiene / methyl methacrylate triblock copolymer of 5 wt% to 40 wt%.

  When the number average molecular weight of each block is outside the above range, or when the content of each block in the triblock copolymer is outside the above range, the effect of improving the high temperature sliding flexibility of the adhesive composition is not sufficient. In addition, there is a possibility that characteristics other than high-temperature sliding flexibility, that is, various characteristics such as adhesiveness, heat resistance, and flame retardancy may be deteriorated.

Such a triblock copolymer of component (C) can be produced, for example, by the method described in European Patent Application No. 0,524,054 or European Patent Application No. 0,749,987. In the above method, each monomer having a predetermined concentration is synthesized by anionic polymerization, and the produced triblock body can be purified and produced by solid-liquid extraction using cyclohexanone as a selective solvent. Production examples (A1, A2) of the triblock copolymer of component (C) produced according to the above method are shown below. In addition, [dimension] in the following example is obtained by cutting an ultrathin piece from a molded product molded using the triblock copolymer, staining with osmic anhydride (OsO ₄ ), and observing with a transmission electron microscope. It was obtained by measurement.

(Triblock copolymer (A1))
[Dimensions] 70-180nm
[Styrene block] Number average molecular weight 50000 g / mol, content in triblock copolymer 50% by weight
[Butadiene block] Number average molecular weight 15000 g / mol, content in triblock copolymer 15% by weight
[Methyl methacrylate block] Number average molecular weight 35000 g / mol, content in triblock copolymer 35% by weight

(Triblock copolymer (A2))
[Dimensions] 70-180nm
[Styrene block] Number average molecular weight 45000 g / mol, content in triblock copolymer 35% by weight
[Butadiene block] Number average molecular weight 20000 g / mol, content in triblock copolymer 31% by weight
[Methyl methacrylate block] Number average molecular weight 35000 g / mol, content in triblock copolymer 34% by weight

  As such a triblock copolymer of the component (C), a commercially available product can be used. For example, NANOSTRENGTH E20, E40, M22 (trade name) manufactured by Arkema Co., Ltd. can be used.

  The adhesive composition of the present invention comprises the (A) component epoxy resin, the (B) component epoxy curing agent, and the (C) component triblock copolymer as essential components. Insofar as it does not violate the purpose, a curing accelerator, an inorganic filler, a synthetic rubber, a pigment, other flame retardants and the like can be contained.

  Any curing accelerator may be used as long as it is usually used as an epoxy resin curing accelerator. Specifically, a tertiary amine, imidazole, aromatic amine, boron trifluoride amine complex, or the like may be used. it can.

  The inorganic filler is used as an auxiliary additive for improving the flame retardancy, and can be used within a range not impairing various properties as an adhesive. Examples of such inorganic fillers include metal hydrates such as aluminum hydroxide and magnesium hydroxide, talc, silica, alumina and the like, and these can be used alone or in admixture of two or more. . When an inorganic filler is contained, the content is preferably 1% by weight or more and 30% by weight or less in the adhesive composition. If it is less than 1% by weight, there is no sufficient effect for improving the flame retardancy, and if it exceeds 30% by weight, the adhesive composition becomes hard and brittle, resulting in a decrease in adhesive strength and the like.

  Synthetic rubber is used for imparting flexibility to the cured product of the adhesive composition and improving sliding bending characteristics. For example, acrylic rubber, acrylonitrile butadiene rubber, styrene butadiene rubber, butadiene methyl acrylate acrylonitrile rubber, Examples thereof include butadiene rubber, carboxyl group-containing acrylonitrile butadiene rubber, vinyl-containing acrylonitrile butadiene rubber, silicone rubber, urethane rubber, and polyvinyl butyral. These can be used alone or in combination of two or more.

  When synthetic rubber is contained, it is preferably 10 parts by weight or more and 200 parts by weight or less, more preferably 15 parts by weight or more and 150 parts by weight or less, with respect to 100 parts by weight of the epoxy resin of component (A). If the content of the synthetic rubber is less than 10 parts by weight, there is no sufficient effect for improving the flexibility and sliding bending characteristics, and if it exceeds 200 parts by weight, the heat resistance may be impaired.

  In addition, the adhesive composition of the present invention can be imparted with flame retardancy by modification with an epoxy resin having a halogen such as bromine or an additive bromine compound. Further, it is possible to impart flame retardancy without halogen by modifying siloxane and phosphorus compounds.

  In this case, condensed phosphoric acid ester, phosphoric acid ester amide and phosphazene compound are optimal as the phosphorus compound. For example, the phosphazene compound is substantially free of halogen, and has heat resistance, moisture resistance and flame retardancy. From the viewpoint of chemical resistance, a phosphazene compound having a melting point of 80 ° C. or higher can be preferably used. Such a phosphazene compound is preferably 10 parts by weight or more and 200 parts by weight or less, more preferably 15 parts by weight or more with respect to 100 parts by weight of the epoxy resin of component (A), from the balance of flame retardancy and other physical properties. More preferably, it is 150 parts by weight or less.

（但し、式中、Ｘは水素原子またはハロゲンを含まない有機基であって、それらが互いに同じでも異なっていてもよい。また、ｎは、３〜１０の整数を表す。）
なお、このシクロホスファゼン化合物における置換基Ｘのハロゲンを含まない有機基としては、炭素数１〜１５のアルコキシ基、フェノキシ基、アミノ基、アリル基などが挙げられる。 Suitable examples of the phosphazene compound include cyclophosphazene compounds represented by the following general formula.

(In the formula, X is an organic group containing no hydrogen atom or halogen, and they may be the same or different from each other. N represents an integer of 3 to 10.)
In addition, as an organic group which does not contain the halogen of the substituent X in this cyclophosphazene compound, a C1-C15 alkoxy group, a phenoxy group, an amino group, an allyl group etc. are mentioned.

  The adhesive composition of the present invention can be prepared by employing a known method. For example, after blending the above-mentioned essential components and other components that are added as necessary, kneading at room temperature or under heating using a known kneader such as a pot mill, ball mill, bead mill, roll mill, homogenizer, super mill, or raikai machine Can be prepared. Moreover, it can use as a viscosity which adds a solvent and suits a processing method. Solvents include alcohol solvents such as methanol, ethanol and isopropanol, ketone solvents such as acetone and methyl ethyl ketone, hydrocarbon solvents such as benzene, toluene and xylene, 1,4-dioxane, 1,3-dioxane and propylene glycol. Examples include ether solvents such as monomethyl ether, N-methylpyrrolidone, dimethylformamide, and the like. These may be used alone or in combination of two or more.

  Such an adhesive composition of the present invention can be suitably used as an adhesive in the production of coverlays, flexible metal foil-clad laminates, flexible wiring boards, wiring boards with reinforcing plates, and the like. By using the adhesive composition of the present invention for these products, the sliding and bending characteristics of the product can be made extremely excellent, and the adhesiveness and heat resistance can be made good.

  That is, as a coverlay, an adhesive layer made of the adhesive composition of the present invention is formed on a base film. As the base film, for example, a film having a thickness of 5 μm or more and 50 μm or less is suitably used. If the thickness of the base film is less than 5 μm, reliability with respect to pinholes, strength, etc. cannot be ensured, and if it exceeds 50 μm, the sliding and bending characteristics may be deteriorated and the reliability may be deteriorated.

  Moreover, as a base film, plastic films, such as a polyimide film, a polyparaphenylene terephthalamide film, a polyether nitrile film, a polyether sulfone film, a polyethylene terephthalate film, a polyethylene naphthalate film, a polyvinyl chloride film, are used, for example. Among these, polyimide film, polyethylene terephthalate film, polyethylene naphthalate film are preferably used from the viewpoints of heat resistance, dimensional stability, electrical properties, mechanical properties, chemical resistance and cost, and polyimide film is particularly preferred. Used for.

  Such a coverlay can be easily manufactured by applying and drying the adhesive composition of the present invention on the base film as described above by a known method. That is, after applying the adhesive composition of the present invention on the base film as described above by the bar coating method, knife coating method, roll coating method, blade coating method, die coating method or gravure coating method, this coating was performed. It can be easily produced by drying the adhesive composition to a semi-cured state. At this time, it is preferable that the coating thickness of the adhesive composition (the thickness of the adhesive layer) is 5 μm or more and 20 μm or less. By setting the thickness to 5 μm or more and 20 μm or less, heat resistance characteristics such as solder heat resistance can be improved, and sliding bending characteristics can also be improved.

  About such a coverlay, you may provide a release sheet in an adhesive bond layer as needed. Examples of such release sheets include paper substrates such as glassine paper, coated paper, cast coated paper, laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper substrates, or polyethylene terephthalate, polybutylene terephthalate. In addition, a film obtained by applying a release agent such as a silicone resin to a plastic film such as a polyester film such as polyethylene naphthalate or a polyolefin film such as polypropylene or polyethylene.

  Moreover, as an adhesive film, the adhesive composition of this invention is formed in a film form. Such an adhesive film can be easily manufactured by using a release sheet as described above instead of the base film in the manufacture of the coverlay as described above. That is, the adhesive composition of the present invention is applied on a release sheet by a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method or a gravure coating method, and then the applied adhesive composition. Can be easily produced by subjecting to a semi-cured state by drying.

  Furthermore, as a flexible metal foil tension laminated board, metal foil is joined via the adhesive composition of this invention on an electrically insulating film. The electrically insulating film is not particularly limited, and any one of those used as the electrically insulating film in the conventional flexible metal foil-clad laminate can be appropriately selected and used. Specifically, plastic films such as polyimide film, polyparaphenylene terephthalamide film, polyether nitrile film, polyether sulfone film, polyethylene terephthalate film, polyethylene naphthalate film, and polyvinyl chloride film are used. Among these, polyimide film, polyethylene terephthalate film, polyethylene naphthalate film are preferably used from the viewpoints of heat resistance, dimensional stability, electrical properties, mechanical properties, chemical resistance and cost, and polyimide film is particularly preferred. Used for.

  Moreover, although copper foil, aluminum foil, etc. are mentioned as metal foil, Among these, copper foil is used suitably. The flexible metal foil-clad laminate produced using the adhesive composition of the present invention is preferably a flexible copper-clad laminate in which a polyimide film is used as the electrically insulating film and a copper foil is used as the metal foil. As mentioned.

  Such a flexible metal foil-clad laminate can be produced by a known production method except that the adhesive composition of the present invention is used as the adhesive composition. For example, after applying the adhesive composition of the present invention on an electrically insulating film by a bar coating method, knife coating method, roll coating method, blade coating method, die coating method or gravure coating method, the applied adhesive composition The product is dried to be in a semi-cured state, and a metal foil is superimposed on the semi-cured adhesive composition and heated and pressure-bonded by a hot press at 100 ° C. to 250 ° C. to adhere the semi-cured state. A flexible metal foil-clad laminate can be produced by completely curing the agent composition. In addition, it is preferable to perform such pressurization and pressure bonding in a reduced pressure environment.

  Moreover, as a flexible wiring board, a circuit is formed on the metal foil in the flexible metal foil-clad laminate. That is, a flexible wiring board is manufactured by selectively removing an unnecessary portion of the metal foil in the flexible metal foil-clad laminate according to a desired circuit pattern. As the metal foil-clad laminate used in the manufacture of such a flexible wiring board, a polyimide film is used as the above-mentioned electrical insulating film, and a flexible copper-clad laminate in which a copper foil is used as the metal foil is preferable. It is mentioned as a thing.

  And it is preferable to provide a coverlay in the circuit formation surface (metal foil surface) of such a flexible wiring board. As such a coverlay, in particular, a coverlay whose adhesive layer is made of the adhesive composition of the present invention is preferably used. The coverlay is bonded to the flexible wiring board by, for example, overlaying the coverlay on the circuit forming surface of the flexible wiring board so that the adhesive layer side is the circuit forming surface side, and then 100 ° C to 250 ° C. It can be carried out by heat-pressing the whole by hot pressing and completely curing the semi-cured adhesive layer. In addition, it is preferable to perform such pressurization and pressure bonding in a reduced pressure environment.

  Moreover, as a wiring board with a reinforcement board, such a flexible wiring board and a reinforcement board are joined through the adhesive film which consists of an adhesive composition of this invention. The flexible wiring board may not have a cover lay, or may have a cover lay. Although it does not specifically limit as a reinforcement board, A glass base material epoxy resin laminated board, a paper base material phenol resin laminated board, a polyester film, a polyimide film, a polyetherimide film, a stainless steel board, an aluminum board, etc. are mentioned.

  In such a wiring board with a reinforcing board, the flexible wiring board and the reinforcing board are overlapped via an adhesive film made of the adhesive composition of the present invention, and then the whole is heated by a hot press at 100 ° C to 250 ° C. By pressure bonding, a semi-cured adhesive film can be completely cured and manufactured. In addition, it is preferable to perform such pressurization and pressure bonding in a reduced pressure environment.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited by these Examples.

(Example 1)
200 parts by weight of carboxyl group-containing acrylonitrile butadiene rubber Nipol 1072 (manufactured by Nippon Zeon Co., Ltd., nitrile content 27), 320 parts by weight of bisphenol A type epoxy resin Epicoat 1001 (manufactured by Yuka Shell Co., Ltd., epoxy equivalent 470), 339 weights Part of naphthalene skeleton epoxy resin NC-7000L (manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 230), 300 parts by weight of phenoxyphosphazene oligomer (manufactured by Otsuka Chemical Co., Ltd., melting point 100 ° C.), styrene / butadiene / methyl methacrylate triblock copolymer As a solvent, a mixture of 10 parts by weight, 300 parts by weight of aluminum hydroxide and 0.5 parts by weight of 2-ethyl-4methylimidazole was used as a solvent. The glycol monomethyl ether (PGM) and Methyl ethyl ketone was added solids 40 wt% adhesive composition A was prepared.

  The thickness of the adhesive composition A after drying with a roll coater on the surface of a 12.5 μm thick polyimide film Kapton (manufactured by Toray DuPont Co., Ltd.) The cover lay was manufactured by coating and drying to 15 μm. And this cover lay was overlap | superposed on the two-layer flexible copper clad board (ESPANEX MC-18-25-00, Nippon Steel Chemical Co., Ltd. product) which carried out the soft etching process of the copper surface, 160 degreeC, 4 Mpa, Heating and pressure bonding was performed for 1 hour to produce a flexible wiring board for evaluation.

(Example 2)
200 parts by weight of carboxyl group-containing acrylonitrile butadiene rubber Nipol 1072 (manufactured by Nippon Zeon Co., Ltd., nitrile content 27), 74 parts by weight of bisphenol A type epoxy resin Epicoat 1001 (manufactured by Yuka Shell Co., Ltd., epoxy equivalent 470), 226 weights Part of biphenyl skeleton epoxy resin NC-3000-H (manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 289), 180 parts by weight of phenol novolac resin (Showa High Polymer Co., Ltd., hydroxyl value 106), 300 parts by weight of phenoxyphosphazene oligomer (Manufactured by Otsuka Chemical Co., Ltd., melting point 100 ° C.) 5 parts by weight of triblock copolymer (A2) in the above-described production example as styrene / butadiene / methyl methacrylate triblock copolymer, 300 parts by weight of aluminum hydroxide and double Propylene glycol monomethyl ether (PGM) and methyl ethyl ketone was added adhesive composition solids 34% by weight B as a solvent was prepared in a mixture consisting of 2-ethyl-4-methylimidazole parts.

  Thereafter, a coverlay was produced in the same manner as in Example 1 except that this adhesive composition B was used, and a flexible wiring board for evaluation was further produced.

(Comparative Example 1)
In the production of the adhesive composition A of Example 1, the adhesive composition C was prepared under the same composition and conditions except that the triblock copolymer (A1) as a styrene / butadiene / methyl methacrylate triblock copolymer was not added. did. Then, except having used this adhesive composition C, it carried out similarly to Example 1, and manufactured the coverlay, and also manufactured the flexible wiring board for evaluation.

(Comparative Example 2)
In the production of the adhesive composition B of Example 2, an adhesive composition D was prepared under the same composition and conditions except that the triblock copolymer (A2) as a styrene / butadiene / methyl methacrylate triblock copolymer was not added. did. Then, except having used this adhesive composition D, it carried out similarly to Example 1, and manufactured the coverlay, and also manufactured the flexible wiring board for evaluation.

  Table 1 summarizes the compositions of the adhesive compositions A to D. Here, the adhesive compositions A to B contain a styrene / butadiene / methyl methacrylate triblock copolymer in a range of 1 to 30 parts by weight with respect to 100 parts by weight of the total epoxy resin. The details of the structure dimensions and the like of each styrene / butadiene / methyl methacrylate triblock copolymer are as described above.

  Next, with respect to the flexible wiring boards for evaluation of Examples and Comparative Examples, the peel strength, solder heat resistance, and high-temperature sliding flexibility were measured and evaluated. Moreover, the glass transition temperature (Tg) of the used adhesive composition AD was measured. The evaluation method and the like are as shown below. The results are shown in Table 2.

(Stripping strength)
About the flexible wiring board for evaluation, the peeling strength when peeling a coverlay from a flexible copper clad board according to IPC-FC-240B was measured. The reflow conditions were a peak temperature of 240 ° C., a preheat temperature of 180 ° C., a preheat time of 90 seconds, a reflow temperature of 220 ° C., and a reflow time of 40 seconds.

(Solder heat resistance)
The flexible wiring board for evaluation was dried by heating at 100 ° C. for 60 minutes, and then floated in a solder bath at 288 ° C. or 300 ° C. for 20 seconds to observe the presence or absence of swelling.

(High temperature sliding flexibility)
Regarding the flexible wiring board for evaluation, in accordance with JIS C 6471, a frequency of 1500 cpm, a stroke of 25 mm, a radius of curvature of 2.5 mm, a temperature condition of 80 ° C., a pattern (conductor width 0.1 mm / A bending test was performed at an interval of 0.1 mm, and the number of bendings until the resistance value increase due to the occurrence of cracks reached 20% or more of the initial value was measured.

(Glass transition temperature (Tg))
About the hardened | cured material of the adhesive composition used for manufacture of the flexible wiring board for evaluation, it measured by DMA (dynamic viscoelasticity measuring apparatus).

  As is apparent from Table 2, Examples and Comparative Examples having the same composition except for containing a styrene / butadiene / methyl methacrylate triblock copolymer having a predetermined size (for example, Example 1 and Comparative Example 1) It can be seen that the example containing the styrene / butadiene / methyl methacrylate triblock copolymer having a predetermined dimension has remarkably improved high-temperature sliding flexibility. In addition, with respect to other characteristics, it can be seen that the characteristics of the example are almost equal to or higher than those of the comparative example.

Claims (8)

(A) a polyepoxide compound,
(B) a curing agent for epoxy, and
(C) an adhesive composition comprising a styrene / butadiene / methyl methacrylate triblock copolymer as an essential component,
The size of the structure of the styrene / butadiene / methyl methacrylate triblock copolymer as the component (C) is 60 nm or more and 5000 nm or less, and the styrene as the component (C) with respect to 100 parts by weight of the polyepoxide compound as the component (A). / Adhesive composition for flexible wiring board, comprising 1 part by weight or more and 30 parts by weight or less of / butadiene / methyl methacrylate triblock copolymer. 2. The adhesive composition for flexible wiring boards according to claim 1, wherein each block in the styrene / butadiene / methyl methacrylate triblock copolymer of component (C) is as shown in the following (1) to (3). .
(1) A styrene block having a number average molecular weight of 20,000 g / mol to 200,000 g / mol and having a content in the styrene / butadiene / methyl methacrylate triblock copolymer of 30 wt% to 60 wt%.
(2) A butadiene block having a number average molecular weight of 10,000 g / mol to 200,000 g / mol and having a content in the styrene / butadiene / methyl methacrylate triblock copolymer of 10 wt% to 40 wt%.
(3) A methyl methacrylate block having a number average molecular weight of 20,000 g / mol to 200,000 g / mol, and a content in the styrene / butadiene / methyl methacrylate triblock copolymer of 5 wt% to 40 wt%.   A coverlay comprising a polyimide film and an adhesive layer formed on the surface of the polyimide film using the adhesive composition for a flexible wiring board according to claim 1 or 2.   An adhesive film formed by forming the adhesive composition for flexible wiring boards according to claim 1 or 2 into a film shape.   A flexible copper-clad laminate comprising: a polyimide film; and a copper foil bonded to at least one main surface of the polyimide film with the adhesive composition for a flexible wiring board according to claim 1.   A flexible wiring board comprising a circuit formed on the copper foil in the flexible copper-clad laminate according to claim 5.   The flexible wiring board according to claim 6, wherein the coverlay according to claim 3 is bonded onto the circuit.   A wiring board with a reinforcing board, wherein the flexible wiring board according to claim 6 and the reinforcing board are bonded together via the adhesive film according to claim 4.