JP2010074050A - Adhesive composition for flexible printed wiring board and adhesive film using the adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition for a flexible printed wiring board, which displays excellent solder heat resistance and adhesive force by heat curing for a short time, and has a good punching property in a B stage (a state before curing) and to provide an adhesive film using the adhesive composition. <P>SOLUTION: The adhesive composition for the flexible printed wiring board contains epoxy resin (A), phenol resin (B), elastomer (C) having a functional group reacting with the (A) or (B), a microcapsule type curing agent (D), an inorganic filler (E), and silicon oligomer (F); wherein the blending amount of the microcapsule type curing agent (D) to the total 100 pts.mass of the epoxy resin (A) and the phenol resin (B) is 5 to 100 pts.mass. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is an adhesive for a flexible printed circuit board (hereinafter referred to as FPC) which exhibits excellent solder heat resistance and adhesive strength by short-time thermosetting, and has good punchability in a B stage (before curing). The present invention relates to a composition and an adhesive film using the composition.

  In recent years, the electronic materials industry has made remarkable progress, and the life cycle of electronic devices has been shortening year by year. In addition, with the globalization of electric devices such as portable devices, further reduction in lead time is required.

  However, the conventional adhesives and adhesive films used in the flexible printed wiring board industry are mainly cured by pressing or oven, and the curing time also needs to be 30 minutes to 2 hours. Met.

  In addition, an epoxy resin adhesive composition that is generally used as an adhesive is obtained by using an acid anhydride, an aromatic amine or the like as a curing agent, so that good adhesion and solder heat resistance can be obtained. There is a problem that sufficient room temperature storage stability cannot be obtained, and Lewis acids, amine complexes and the like have been proposed, but they are not suitable for short-time curing (see Reference 1).

  In addition to thermosetting adhesives, there is also a pressure-sensitive adhesive film with tackiness, but the solder heat resistance is insufficient, and in the future it will not be able to cope with lead-free solder, which will become the mainstream due to environmental issues Moreover, since it has adhesiveness and is soft, there is a disadvantage that punchability at the B stage stage is inferior.

  Furthermore, although an ultraviolet curing type adhesive film has been proposed, there is a problem that enormous capital investment is required and conventional equipment cannot cope with it.

  Since the flexible printed wiring board is used by being punched into various shapes, punchability is required, and as a technique for improving the punchability, there is a method using an inorganic filler in combination. However, usually, when an inorganic filler is blended in a resin varnish, there are problems of dispersibility and precipitation of the inorganic filler. In addition, when the sedimentation is significant, the inorganic filler accumulates at the bottom of the container and hardens due to aggregation or the like, and it is difficult to sufficiently disperse only by stirring.

  As a method for improving the dispersibility of the filler, there is a method using a filler whose surface has been previously treated with a surface treatment agent such as a coupling agent (see References 2, 3, and 4). However, since the types of commercially available treatment fillers are very limited, it has been difficult to select treatment fillers suitable for various resin compounding systems. On the other hand, for the purpose of further improving the functionality, the blending amount of the filler in the resin material tends to increase. As the amount of the filler is increased, the above sedimentation becomes more and more remarkable, and more excellent dispersibility and thixotropy than before are required. Satisfying these characteristics has become difficult with conventional treatment methods using coupling agents.

JP 2008-247472 A JP-A 63-230729 Japanese Patent Publication No.62-40368 JP-A-61-272243

  The present invention has been made in view of the above-mentioned problems of the prior art. The object of the present invention is to exhibit excellent solder heat resistance and adhesive force by short-time thermosetting, and to provide a B stage ( It is to provide an adhesive composition for a flexible printed wiring board (hereinafter referred to as FPC) having good punchability in a state before curing) and an adhesive film using the same.

  In order to solve these problems, the present inventor has intensively studied and required an epoxy resin and a phenol resin, an elastomer having a functional group capable of reacting with an epoxy resin or a phenol resin, a microcapsule type curing agent, an inorganic filler, and a silicone oligomer. By using it as a component, it has been found that it exhibits excellent solder heat resistance and adhesive strength in a short time of heat curing, and has good punchability in the B stage (state before curing). It came to complete.

That is, the present invention relates to [1] an epoxy resin (A), a phenol resin (B), an elastomer (C) having a functional group that reacts with (A) or (B), a microcapsule type curing agent (D), an inorganic The filler (E) and the silicone oligomer (F) are included, and the blending amount of the microcapsule type curing agent (D) is 100 parts by mass with respect to a total of 100 parts by mass of the epoxy resin (A) and the phenol resin (B). ) Is an adhesive composition for a flexible printed wiring board having 5 to 100 parts by mass.
Further, the present invention provides: [2] The silicone oligomer (F) has a degree of polymerization of 2 to 70, has one or more functional groups that react with a hydroxyl group, and R ₂ SiO _2/2 , RSiO _3/2. And at least one siloxane unit selected from the group consisting of SiO _4/2 , wherein in the siloxane unit, R is an organic group, and when a plurality of Rs are included, the Rs are the same It is related with the adhesive composition for flexible printed wiring boards as described in said [1] which may be different.
Moreover, this invention relates to the adhesive film formed into a film using the adhesive composition for flexible printed wiring boards as described in [3] said [1] or said [2].

  According to the present invention, the epoxy resin (A), the elastomer (C) having a functional group that reacts with the phenol resin (B) (A) or (B), the microcapsule type curing agent (D), the inorganic filler (E ), And an adhesive composition for a flexible printed wiring board containing silicone oligomer (F) as an essential component, exhibiting excellent solder heat resistance and adhesive force in a short time of thermosetting, and B It is possible to provide an adhesive composition for a flexible printed wiring board having good punchability on the stage (the state before curing) and an adhesive film using the same.

  Hereinafter, embodiments of the present invention will be specifically described.

The main components of the adhesive used in the present invention are an epoxy resin (A) and a phenol resin (B) which is a curing agent thereof, and other resins may be blended as long as the properties are not disturbed. As these resins, xylene resins, guanamine resins, diallyl phthalate resins, vinyl ester resins, unsaturated polyester resins, furan resins, polyimide resins, polyurethane resins, cyanate resins, maleimide resins, benzocyclobutene resins, and the like can also be used.
The epoxy resin (A) includes bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin and other bisphenol type epoxy resins, phenol novolac type epoxy resins, cresol novolak type epoxy resins, bisphenol A novolak type epoxy resins. Novolak type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, diglycidyl etherified product of biphenol, diglycidyl etherified product of naphthalenediol, diglycidyl etherified product of phenol, diglycidyl etherified product of alcohol , And their alkyl-substituted products, halides, hydrogenated products, and the like. One type of epoxy resin may be used alone, or two or more types may be mixed and used.
The phenol resin (B) is obtained by reacting a phenol and an aldehyde with an acid or alkali as a catalyst. As the phenol, phenol, metacresol, paracresol, orthocresol, isopropylphenol, nonylphenol or the like is used. Examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, paraacetaldehyde, butyraldehyde, octylaldehyde, benzaldehyde and the like, and are not particularly limited. In general, formaldehyde or paraformaldehyde is used. In addition, a vegetable oil-modified phenol resin can also be used. The vegetable oil-modified phenol resin is obtained by reacting phenols and vegetable oil in the presence of an acid catalyst, and then reacting aldehydes in the presence of an alkali catalyst. Examples of the acid catalyst include p-toluenesulfonic acid. Examples of the alkali catalyst include amine catalysts such as ammonia, trimethylamine, and triethylamine.
The epoxy resin (A) and the phenol resin (B) are based on the epoxy equivalent of the epoxy resin.
The hydroxyl group equivalent of the phenol resin is preferably blended in the range of 1: 0.8 to 1.10.

The elastomer (C) having a functional group that reacts with (A) or (B) used in the present invention may have a functional group that reacts with the epoxy resin (A) or the phenol resin (B). , Molecular weight, composition, etc., can be used without particular limitation, and functional groups that react with epoxy resins or phenol resins include carboxyl groups, glycidyl groups, hydroxyl groups, etc. Among them, these resins contain carboxyl groups It is preferable. When it contains a carboxyl group, when the resulting composition is applied to an adhesive film, the reactivity with the thermosetting component tends to increase and the heat resistance tends to increase.
Examples of elastomers that can have a functional group include acrylonitrile-butadiene rubber, acrylic rubber, acrylic acid alkyl ester (including methacrylic acid ester) as a main component, vinyl monomer and, if necessary, acrylonitrile, styrene, etc. Copolymer, polyisoprene, polybutadiene, styrene-butadiene-styrene copolymer, butyl rubber, chloroprene rubber, nitrile rubber, acrylonitrile-butadiene-methacrylic acid copolymer, styrene-isoprene copolymer, styrene-butylene-styrene Examples include block copolymers, styrene-ethylene-butylene-styrene block copolymers, and more specifically, carboxyl group-containing acrylic rubber, carboxyl group-terminated polybutadiene, hydroxyl group-terminated polybutadiene, carboxyl group-terminated 1,2-polybutadiene, hydroxyl-terminated 1,2-polybutadiene, hydroxyl-terminated styrene-butadiene rubber, carboxyl group, hydroxyl group, (meth) acryloyl group or morpholine group-containing acrylonitrile-butadiene rubber, carboxylated nitrile rubber, Examples include hydroxyl-terminated poly (oxypropylene), poly (oxytetramethylene) glycol, polyolefin glycol, poly-ε-caprolactone, and the like.

  The microcapsule type curing agent (D) is a thin layer coated with a coating agent to such an extent that the microcapsule is easily broken by applying pressure or temperature. For example, NovaCure HX-3612, -3722, -3741, 3748 (trade name, manufactured by Asahi Kasei Chemicals Corporation).

  A microcapsule type hardening | curing agent (D) is 5-100 mass parts with respect to a total of 100 mass parts of an epoxy resin (A), a phenol resin (B), or resin mix | blended as needed. If the amount is less than 5 parts by mass, the desired heat resistance cannot be obtained. If the amount exceeds 100 parts by mass, the unreacted microcapsule type curing agent (D) remains, and the heat resistance tends to decrease.

  The average particle size of the microcapsule type curing agent (D) is preferably 5 μm or less, preferably 1 to 3 μm. Also, if the average particle size of the microcapsule type curing agent exceeds 5 μm, the area in contact with the resin composition constituting the adhesive composition decreases, so that high temperature and long time are required for adhesion, and the average If the particle size becomes too small, the life tends to be shortened.

  The inorganic filler (E) used in the present invention is not particularly limited and can be used as long as it is essentially electrically insulating. For example, metal hydroxide such as aluminum hydroxide and magnesium hydroxide can be used. And metal oxides such as aluminum oxide and calcium oxide, silica, mica, talc, clay and the like. In the present invention, it is particularly preferable to use aluminum hydroxide or silicon oxide as the inorganic filler. Aluminum hydroxide and silicon oxide are preferable because they have few ionic impurities and are low in cost, and are widely used for electronic materials including FPC. These can be used alone or in combination of two or more as required. There is no restriction | limiting in particular about the shape of a inorganic filler, and a particle size, Usually, the particle size of 0.01-50 micrometers, Preferably 0.1-15 micrometers is used suitably. The blending amount of these inorganic fillers is preferably in the range of 5 to 100 parts by mass with respect to 100 parts by mass in total of the resin solids of (A) + (B) + (C). If it is less than 5 parts by mass, the B-stage will be poorly cut and will tend to adhere to the punching blade, etc., and the desired punchability will not be obtained. If it exceeds 100 parts by mass, the normal peel adhesion strength will be low. There is a tendency to decrease.

  The adhesive composition for flexible printed wiring boards of the present invention may be used in combination with a microcapsule type curing agent (D), and various conventionally known ones may be added as reaction accelerators or curing catalysts. For example, amine complexes of boron trifluoride such as diaminodiphenylmethane, diaminodiphenylsulfone, aromatic polyamine, boron trifluoride triethylamine complex, 1-alkyl-2-phenylimidazole, 2-alkyl-4-methylimidazole, 2-phenyl Imidazole derivatives such as -4-alkylimidazole, organic acids such as pyromellitic anhydride, phthalic anhydride, trimellitic anhydride, dicyandiamide, triphenylphosphine, diazabicycloundecene, hydrazine, organophosphorus compounds, 3rd Well-known things, such as a quaternary amine and a quaternary ammonium salt, can be used. In addition, these curing catalysts may be used independently and may use 2 or more types together as needed.

  If the silicone oligomer (F) used by this invention has one or more functional groups which react with a hydroxyl group at the terminal, there will be no restriction | limiting in particular in the molecular weight, a structure, etc.

The silicone oligomer (F) used in the present invention is preferably three-dimensionally cross-linked in advance, and therefore, a bifunctional siloxane unit (R ₂ SiO _2/2 ), a trifunctional siloxane unit (RSiO _3/2 ). And tetrafunctional siloxane units (RSiO _4/2 ) (wherein R is an organic group, for example, an alkyl group having 1 or 2 carbon atoms such as a methyl group or an ethyl group, or an aryl having 6 to 12 carbon atoms such as a phenyl group) R group in the silicone oligomer may be the same as or different from each other, and at least one siloxane unit selected from 2 to 70 (converted from the weight average molecular weight by GPC). For example, a bifunctional siloxane unit, a trifunctional siloxane unit, a tetrafunctional siloxane unit, a bifunctional siloxane unit and a trifunctional siloxane unit, a trifunctional siloxane unit, Examples thereof include those composed of tetrafunctional siloxane units, those composed of bifunctional siloxane units and tetrafunctional siloxane units, and those composed of bifunctional siloxane units, trifunctional siloxane units and tetrafunctional siloxane units. Moreover, although the polymerization degree of a silicone oligomer is a thing of 2-70, Preferably, it is a polymerization degree 6-70, More preferably, it is 10-50. If the degree of polymerization is less than 2, a sufficient three-dimensional crosslinked structure cannot be obtained, and if a silicone oligomer having a degree of polymerization of more than 70 is used, uneven treatment may occur during surface treatment and heat resistance may be reduced.

Here, the bifunctional siloxane unit (R ₂ SiO _2/2 ), the trifunctional siloxane unit (RSiO _3/2 ), and the tetrafunctional siloxane unit (SiO _4/2 ) each have the following structure.
R R O-
｜ ｜ ｜
-O-Si-O- -O-Si-O- -O-Si-O-
｜ ｜ ｜
R O- O-

R ₂ SiO _2/2 , RSiO _3/2 , SiO _4/2

  As for the compounding quantity of the silicone oligomer (F) of this invention, 0.01-50 mass% is preferable with respect to an inorganic filler (E). If it is less than 0.01% by mass, the effect of improving the interfacial adhesion may be insufficient, and if it exceeds 50% by mass, the heat resistance and the like tend to decrease.

  The adhesive composition for flexible printed wiring boards and the adhesive film using the same of the present invention can be used by dissolving or dispersing in an organic solvent. The organic solvent is not particularly limited. For example, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, aromatic solvents such as toluene, alcohol solvents such as methanol and ethanol, N-methylpyrrolidone, N, N-dimethylformamide An amide solvent such as may be used.

  The adhesive film of the present invention can be obtained by directly coating an adhesive solution of an adhesive composition for flexible printed wiring boards on a release paper and drying an organic solvent. Although it does not restrict | limit especially as a coating method, A comma coater, a reverse roll coater, etc. are mentioned.

  The release paper used for the above applications is not particularly limited, but for example, a coating layer of a sealant such as clay, polyethylene, or polypropylene on both surfaces of paper such as fine paper, kraft paper, and glassine paper. Further, a silicone-based, fluorine-based, or alkyd-type release agent is coated on each coating layer, and polyethylene, polypropylene, ethylene-α-olefin copolymer, propylene-α- Examples include various olefin films such as olefin copolymers alone, and those obtained by applying the release agent on films such as polyethylene terephthalate. From one side or both sides of a high-quality paper and then using a silicone mold release agent on it, What uses the silicone type mold release agent on the ethylene terephthalate is preferable.

  Next, the present invention will be specifically described using examples and comparative examples.

(Synthesis Example 1)
(1) Production of silicone oligomer solution A glass flask equipped with a stirrer, condenser and thermometer was charged with a solution containing 40 g of tetramethoxysilane and 93 g of methanol, and then 0.47 g of acetic acid and 18.9 g of distilled water were added. The mixture was stirred at 50 ° C. for 8 hours to synthesize a silicone oligomer having a degree of polymerization of siloxane units of 20 (converted from a weight average molecular weight by GPC, the same applies hereinafter). The obtained silicone oligomer has a methoxy group and / or a silanol group as a terminal functional group that reacts with a hydroxyl group.
Methanol was added to the obtained silicone oligomer solution to prepare a silicone oligomer treatment liquid having a solid content of 1% by weight.

(2) Preparation of adhesive solution of adhesive composition for flexible printed circuit board After dispersing 20 parts by weight of Aerosil 200 (silicon oxide; trade name of Nippon Aerosil Co., Ltd.) as an inorganic filler (E) in methyl ethyl ketone, Add the silicone oligomer treatment liquid prepared in (1) of Synthesis Example 1 as a silicone oligomer to 0.2 parts by mass and add it as a carboxyl group-containing elastomer (C) to the solution stirred at room temperature (25 ° C.) for 30 minutes. 50 parts by mass of Nipol 1072J (carboxyl group-containing NBR; product name manufactured by Nippon Zeon Co., Ltd.), 25 parts by mass of epoxy resin YDCN703 (cresol novolac type epoxy resin; product name manufactured by Tohto Kasei Co., Ltd.) as epoxy resin (A) TD2625 (resol type phenol resin; phenol resin (B)) Dainippon Ink Co., Ltd. trade name) 25 parts by mass was added. Furthermore, what mixed 10 mass parts of NOVACURE HX3612 (Asahi Kasei Chemicals make brand name) as a microcapsule type hardening | curing agent (D) with the said liquid mixture was used as the adhesive agent solution.

(2) Production of adhesive film An adhesive solution was applied to a separator (hereinafter referred to as a separator) in which a silicone release agent was applied to a 75 μm thick polyethylene terephthalate film so that the adhesive thickness after drying would be 12.5 μm. Then, it was dried at 90 ° C. for 3 minutes in a hot air dryer to prepare an adhesive film.

(Example 2)
In Example 1, it carried out like Example 1 except having made Nipol 1072J acrylic rubber (WS023, Nagase ChemteX Corporation, BA-EA-AN copolymer) which has -OH and -COOH.

(Example 3)
In Example 1, 0 part by mass of YDCN703, 25 parts by mass of ESCN220S (trade name, manufactured by Sumitomo Chemical Co., Ltd., cresol novolac type epoxy resin), 0 part by mass of TD2625, PR54313 (trade name, manufactured by Sumitomo Bakelite Co., Ltd., resol type phenol resin) Example 1 except that 25 parts by mass, Aerosil 200 was 0 parts by mass, H42M (trade name, manufactured by Showa Denko KK, aluminum hydroxide) was 30 parts by mass, and the silicon oligomer treatment liquid was 0.3 parts by mass. The same was done.

Example 4
In Example 1, 0 parts by mass of Nipol 1072J, 60 parts by mass of WS023, 30 parts by mass of YDCN703, 10 parts by mass of TD2625, 20 parts by mass of Novacure HX3612, 40 parts by mass of Aerosil 200, and silicon oligomer treatment liquid It carried out similarly to Example 1 except having set it as 0.4 mass part.

(Example 5)
In Example 4, except that WS023 was 70 parts by mass, YDCN was 20 parts by mass, TD2625 was 0 parts by mass, PR54313 was 10 parts by mass, Aerosil 200 was 50 parts by mass, and the silicon oligomer treatment liquid was 0.2 parts by mass. The same operation as in Example 4 was performed.

(Comparative Example 1)
Example 1 was carried out in the same manner as Example 1 except that 1 part by mass of 2E4MZ (trade name, 2-ethyl-4-methylimidazole, manufactured by Shikoku Kasei Kogyo Co., Ltd.) was used instead of Novacure HX3612.

(Comparative Example 2)
In Example 1, it carried out like Example 1 except having made NovaCure HX3612 into 2 mass parts.

(Comparative Example 3)
In Example 1, it carried out like Example 1 except having made NovaCure HX3612 60 mass parts.

(Comparative Example 4)
In Example 1, it carried out like Example 1 except having made Aerosil 200 into 0 mass part.

(Evaluation methods)
(1) Peel adhesion strength (normal state)
After bonding the adhesive film surface of an adhesive film with a 50 μm polyimide film Kapton200H (manufactured by DuPont) and a separator (release paper) with a laminating roll at 100 ° C. (linear pressure 5 kg / cm, laminating speed 1 m / min) A 50 μm polyimide film Kapton 100H was bonded to the adhesive film surface from which the separator had been peeled off with a laminating roll at 100 ° C. (linear pressure: 5 kg / cm, laminating speed: 1 m / min). Then, what was pressed (temperature 170 ° C., pressure 1 MPa, 2 minutes) was used as a test piece. The cured test piece was measured for 90 ° peel adhesion strength in accordance with JIS K 6854-3. The peeling temperature was 23 ° C., and the peeling speed was 10 mm / min.
(2) Reflow soldering heat resistance The adhesive film surface of the adhesive film with a 50 μm polyimide film Kapton200H (manufactured by DuPont) and a separator (release paper) is laminated on a 100 ° C. roll (linear pressure 5 kg / cm, laminating speed 1 m / min). Then, a 50 μm polyimide film Kapton 200H was bonded to the adhesive film surface from which the separator had been peeled off with a laminating roll at 100 ° C. (linear pressure: 5 kg / cm, laminating speed: 1 m / min). Then, what was pressed (temperature 170 ° C., pressure 1 MPa, 2 minutes) was used as a test piece. After the test piece was left in a humidified condition (temperature 40 ° C., relative humidity 80%) for 12 hours in accordance with JIS C 6481, the surface of the sample was measured using a reflow soldering apparatus (RF430, manufactured by Nippon Pulse Laboratories). The test piece was heated so that the maximum temperature was 260 ° C., and the presence or absence of swelling of the adhesive layer was observed.
Then, the case where there was no bulge or peel was evaluated as “◯”, and the case where there was bulge or peel was evaluated as “x”.
(3) Flow-out property After bonding the adhesive film surface of the adhesive film with 25 μm polyimide film Kapton100H and the separator with a laminating roll (linear pressure 5 kg / cm, laminating speed 1 m / min) at 100 ° C., A 25 μm polyimide film Kapton 100H was bonded to the adhesive film surface from which the separator had been peeled off with a laminating roll (linear pressure 5 kg / cm, laminating speed 1 m / min) at 100 ° C. The test piece was cut into 80 mm × 80 mm and pressed (170 ° C. × 1 MPa × 2 minutes). Thereafter, the maximum protruding portion on each of the four sides was measured with a caliper, and the average was taken as the flow-out amount (mm).
For the evaluation of the flow-out amount, the average flow-out amount was evaluated as “◯” when less than 0.2 mm, and “×” when 0.2 mm or more.
(4) Punching property With the adhesive film surface of the adhesive film facing up, punching was performed with a No. 2 dumbbell. The evaluation was performed 10 times, and the breakage of the adhesive film and the stringing were visually confirmed when punched.
As the punchability, the number of times that the N number (test number) was used in the denominator, the numerator was well cut, and the punching was good without stringing.
The results of Examples 1 to 5 and Comparative Examples 1 to 3 are shown in Table 1.

表中の部数は溶剤を除いた質量部比
はんだ耐熱性の評価；○：フクレ・ハガレなし ×：フクレ・ハガレあり
流れ出し量の評価；○:０．２ｍｍ未満 ×：０．２ｍｍ以上
打ち抜き性；分母がＮ数（試験数）、分子が打ち抜き良好となった回数

The number of parts in the table is the evaluation of solder heat resistance relative to the mass part excluding the solvent; ○: No swelling or peeling ×: Evaluation of flowing amount with swelling or peeling; ○: Less than 0.2 mm ×: Punchability of 0.2 mm or more; Number of times the denominator is N number (number of tests) and the numerator is punched well.

The present invention relates to an epoxy resin (A), a phenol resin (B), an elastomer (C) having a functional group that reacts with (A) or (B), a microcapsule curing agent (D), and an inorganic filler (E). , And the silicone oligomer (F), and the blending amount of the microcapsule type curing agent (D) is 5 parts by weight based on the total amount of 100 parts by weight of the epoxy resin (A) and the phenol resin (B). It is the adhesive composition for flexible printed wiring boards which is -100 mass parts.
Comparative Example 1 using an imidazole curing agent was inferior in peel adhesion strength and solder heat resistance because curing was insufficient at 170 ° C. for 2 minutes. On the other hand, the formulation of the microcapsule type curing agent (D) is 4 parts by mass of Comparative Example 2 with respect to the total of 100 parts by mass of (A) + (B). The solder heat resistance is inferior, and 120 parts by mass of Comparative Example 3 is inferior in the flow-out property because it has a large amount of the curing agent and acts as a plasticizer. In the comparative example 4 which does not mix | blend an inorganic filler (E), it is inferior to punching property.
For these comparative examples, the epoxy resin (A) of the present invention, phenol resin (B) (A), elastomer (C) having a functional group that reacts with (B), microcapsule type curing agent (D), inorganic In the adhesive composition for flexible printed wiring boards containing the filler (E) and the silicone oligomer (F) and having an appropriate blending amount of (D), it can be cured in a short time, peel adhesion strength, and reflow soldering heat resistance. Excellent in both punching and the like.

Claims (3)

Epoxy resin (A), phenol resin (B), elastomer (C) having a functional group that reacts with (A) or (B), microcapsule curing agent (D), inorganic filler (E), and silicone oligomer (F) and the amount of the microcapsule type curing agent (D) is 100 parts by mass of the total of the epoxy resin (A) and the phenol resin (B), and the amount of (D) is 5 to 100 parts by mass An adhesive composition for a flexible printed wiring board. The silicone oligomer (F) has a polymerization degree of 2 to 70, has at least one functional group that reacts with a hydroxyl group, and is selected from the group consisting of R ₂ SiO _2/2 , RSiO _3/2 and SiO _4/2. Having at least one selected siloxane unit, wherein in the siloxane unit, R is an organic group, and when a plurality of Rs are included, the Rs may be the same or different. The adhesive composition for flexible printed wiring boards according to claim 1. The adhesive film for flexible printed wiring boards formed into a film using the adhesive composition for flexible printed wiring boards of Claim 1 or Claim 2.