JP4892923B2 - Adhesive composition, circuit terminal connection structure, and circuit terminal connection method - Google Patents

Description

  The present invention relates to an adhesive composition, a circuit terminal connection structure, and a circuit terminal connection method.

  Epoxy resin adhesives are widely used in various applications such as electricity, electronics, architecture, automobiles and aircraft because they have high adhesive strength and are excellent in water resistance and heat resistance. Among them, one-pack type epoxy resin adhesives are used in the form of film, paste, and powder because they do not require mixing of the main agent and curing agent and are easy to use (for example, patent documents). 1). In this case, it is common to obtain specific performance by various combinations of epoxy resins, curing agents and modifiers. However, such an epoxy resin film-like adhesive is excellent in workability, but is insufficient in terms of low-temperature fast curing.

As a low-temperature fast-curing adhesive, a radical-polymerizable adhesive is known (for example, Patent Document 2). However, when low-temperature curability is emphasized, a curing agent (peroxidation) having a low decomposition temperature (half-life temperature) is known. Etc.), the storage stability is lowered. Further, although photocationic curing has been proposed as a curing method by light irradiation and low-temperature heating (for example, Patent Document 3), there may be a problem due to corrosion or the like on a metal member.
Further, a method has been proposed in which a photobase generator and an epoxy resin are used in combination to cure by light irradiation and heating (for example, Patent Document 4). This is based on the principle that a basic compound generated from a photobase generator by light irradiation accelerates the curing reaction between an epoxy resin and a thiol compound at a low temperature, but the structure of the usable thiol compound is rigid. For this reason, the cured product becomes brittle, which may cause problems such as a decrease in adhesion and peeling.

Japanese Patent Laid-Open No. 1-113480 International Publication No. 98/44067 Pamphlet Japanese Patent No. 3392866 JP 2001-279216 A

  An object of the present invention is to provide an adhesive composition that is excellent in low-temperature rapid curing properties and storage stability, and has improved adhesive strength reduction, peeling, etc., a circuit terminal connection structure, and a circuit terminal connection method. It is.

  As a result of earnest research in view of the above problems, the present inventors combined an epoxy resin, a thiol compound having one or more ester bonds in the molecule, and a photobase generator that generates a base by light irradiation. The present inventors have found that the low-temperature fast curability and adhesiveness of the adhesive are improved and that the storage stability is excellent when light is blocked, and the present invention has been completed.

The present invention is as follows.
[1] An adhesive composition containing (A) an epoxy resin, (B) a thiol compound having one or more ester bonds in the molecule, and (C) a photobase generator that generates a base by light irradiation.
[2] (B) The thiol compound is trimethylolpropane tristhioglycolate, pentaerythritol tetrakisthioglycolate, trimethylolpropane tristhiopropionate, pentaerythritol tetrakisthiopropionate, the following general formula (1), ( The adhesive composition according to [1] above, which is at least one compound selected from the group of compounds represented by 2).

（一般式（１）、（２）において、ｍ、ｎは独立に１〜５の整数を示す）

(In general formulas (1) and (2), m and n each independently represents an integer of 1 to 5)

[3] (C) The photobase generator is one or more compounds selected from the group consisting of amine imide derivatives, imidazolium salt derivatives, quaternary ammonium salt derivatives, carbamic acid ester derivatives, oxime ester derivatives, and α-aminoketone derivatives. The adhesive composition according to the above [1] or [2], which is characterized in that it exists.
[4] The adhesive composition according to any one of [1] to [3], further including a thermoplastic resin.
[5] The adhesive composition according to [4], wherein the thermoplastic resin is selected from phenoxy resin, polyester resin, polyurethane resin, polyester urethane resin, butyral resin, and acrylic resin.
[6] The adhesive composition according to any one of [1] to [5], further including conductive particles.
[7] A first circuit member having a first connection terminal and a second circuit member having a second connection terminal are arranged to face the first connection terminal and the second connection terminal. The adhesive composition according to any one of [1] to [6] is interposed between the first connection terminal and the second connection terminal arranged opposite to each other, and A circuit terminal connection structure in which only one connection terminal and the second connection terminal are electrically connected.
[8] The adhesive composition according to any one of [1] to [6] is disposed on a first circuit member having a first connection terminal, and light irradiation is performed from above the adhesive composition. After performing, arrange | positioning the 2nd circuit member which has a 2nd connection terminal facing, and pressurizing while heating, and electrically connecting only the 1st connection terminal and 2nd connection terminal which were opposingly arranged How to connect circuit terminals.
[9] A first circuit member having a first connection terminal and a second circuit member having a second connection terminal are disposed so that the first connection terminal and the second connection terminal face each other. The adhesive composition according to any one of the above [1] to [6] is interposed between the first connection terminal and the second connection terminal arranged to face each other, and the pressure is applied while heating simultaneously with light irradiation. A circuit terminal connection method for electrically connecting only the first connection terminal and the second connection terminal arranged opposite to each other.

  According to the present invention, it is possible to provide an adhesive composition, a circuit terminal connection structure, and a circuit terminal connection method that are excellent in low-temperature fast-curing property and storage stability and excellent in adhesiveness.

  The (A) epoxy resin used in the present invention is not particularly limited as long as it has two or more epoxy groups in the molecule, and known ones can be used. Examples of the compound having at least two epoxy groups in the molecule include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol. A novolac type epoxy resin, bisphenol F novolak type epoxy resin, alicyclic epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, aliphatic chain epoxy resin, etc. Yes, these epoxy resins may be halogenated or hydrogenated. Two or more of these epoxy resins may be used in combination.

  In addition, as the compound having an epoxy group in the present invention, a compound having an epoxy group with an epoxy equivalent of about 43 to 10,000 may be used. If the epoxy equivalent is 43 or more, the crosslinking density can be prevented from decreasing, and if it is 10,000 or less, the tendency of the reaction rate to decrease can be suppressed.

  The (B) thiol compound used in the present invention is not particularly limited as long as it is a thiol compound having one or more ester bonds in the molecule, and known compounds can be used. The (B) thiol compound used in the present invention is characterized by showing good adhesiveness by having a highly polar ester bond in the molecule. Hereinafter, the thiol compound having one or more ester bonds in the molecule is abbreviated as (B) thiol compound.

Such (B) thiol compound preferably has a mercapto group equivalent (hereinafter referred to as SH equivalent) of 100 or more, which is a value obtained by dividing the molecular weight of the thiol compound by the number of functional groups of the mercapto group per molecule of thiol compound. A thiol compound having an ester bond and two or more mercapto groups in the molecule and an SH equivalent of 100 or more is more preferable from the viewpoint of adhesiveness.
Specifically, trimethylolpropane tristhioglycolate, pentaerythritol tetrakisthioglycolate, trimethylolpropane tristhiopropionate, pentaerythritol tetrakisthiopropionate modified with OH group of trimethylolpropane or pentaerythritol, Examples include isocyanurate-modified thiol compounds represented by general formulas (1) and (2), 4,4′-thiodibenzenethiol, and isocyanurate-modified thiol compounds are particularly preferable from the viewpoints of adhesiveness and heat resistance. These thiol compounds may be used alone or in combination of two or more.

（一般式（１）、（２）において、ｍ、ｎは独立に１〜５の整数を示す）

(In general formulas (1) and (2), m and n each independently represents an integer of 1 to 5)

  The amount of (B) thiol compound used should be a ratio of 0.3 / 1.7 to 1.7 / 0.3 in the ratio of SH equivalent / epoxy equivalent to (A) epoxy resin. Is preferable, and a ratio of 0.8 / 1.2 to 1.2 / 0.8 is more preferable. If this ratio is in the range of 0.3 / 1.7 to 1.7 / 0.3, it is possible to prevent a large amount of unreacted thiol groups and epoxy groups from remaining in the cured product. It is possible to suppress the tendency of the mechanical properties to decrease.

(C) The photobase generator that generates a base by light irradiation used in the present invention is not particularly limited as long as it is a compound that generates a base by light irradiation, but it is an amine imide derivative, an imidazolium salt derivative, a quaternary ammonium salt. Derivatives, carbamic acid ester derivatives, oxime ester derivatives, and α-aminoketone derivatives are more preferable from the viewpoint of efficiently generating a base with respect to light irradiation.
The role of the photobase generator in the present invention is based on the premise that a basic compound generated by light irradiation acts as a curing catalyst and promotes curing of the epoxy resin and the thiol compound. For this reason, the basicity of the compound generated by light irradiation is important along with the photobase generation efficiency. As the basic compound generated from the photobase generator, for example, a compound having a pKa of 5 or more, which is a basic index, is preferable. Examples of such compounds include imidazole derivatives, primary amines, secondary amines, tertiary amines, DABCO (triethylenediamine) and DBU (1,8-diazabicyclo [5,4,0] undec-7-ene), DBN (2,6-dichlorobenzonitrile) etc. are mentioned. Examples of photobase generators that generate such basic compounds include Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints, Ed. by G. Bradley, John Wiley and Sons Ltd. (1998), p479 to p545, carbamic acid ester derivatives, oxime ester derivatives, and quaternary ammonium salt derivatives. Further, α-aminoacetophenone derivatives described in JP-A No. 11-71450, amine imide derivatives described in WO 2002/051905 pamphlet, and imidazolium described in JP-A No. 2003-212856. And salt derivatives.

  The amount of the (C) photobase generator used in the present invention is preferably 0.01 to 200 parts by weight, more preferably 0.02 to 150 parts by weight, based on 100 parts by weight of the (A) epoxy resin. If the photobase generator is 0.01 parts by weight or more, the heat resistance can be prevented from decreasing, and if it is 200 parts by weight or less, the film properties are good.

  The adhesive composition of the present invention can further contain a thermoplastic resin. The thermoplastic resin is not particularly limited, but a resin containing a polar group such as a hydroxyl group, an ether group, an ester group, a urethane group, an amide group, an imide group, or a carboxyl group in the main chain skeleton or side chain of the resin. Is preferable from the viewpoint of adhesiveness. Specifically, phenoxy resin, polyester resin, polyurethane resin, polyester urethane resin, polyvinyl butyral resin, polyvinyl formal resin, polyamide resin, polyimide resin, polyacrylic resin, and the like can be used. In addition, a polymer obtained by modifying the polymer with an epoxy group, an acryloyl group, a methacryloyl group, a carboxyl group or the like, which is a reactive functional group, is more preferable because heat resistance is improved.

The molecular weight of these resins is not particularly limited, but the general weight average molecular weight is preferably from 5,000 to 150,000, particularly preferably from 10,000 to 80,000. If this value is 5,000 or more, sufficient film formability can be obtained, and if it is 150,000 or less, the tendency for compatibility with other components to deteriorate can be suppressed. The amount used is preferably 20 to 320 parts by weight per 100 parts by weight of the (A) epoxy resin.
In addition, the weight average molecular weight prescribed | regulated by this invention means what was measured using the analytical curve by a standard polystyrene by the gel permeation chromatography method (GPC) according to the following conditions.
<GPC conditions> Equipment used: Hitachi L-6000 type [Hitachi, Ltd.], Column: Gel Pack GL-R420 + Gel Pack GL-R430 + Gel Pack GL-R440 (3 in total) [trade name, manufactured by Hitachi Chemical Co., Ltd.] , Eluent: tetrahydrofuran, measurement temperature: 40 ° C., flow rate: 1.75 ml / min, detector: L-3300RI [Hitachi, Ltd.]

  The adhesive composition of the present invention may further contain conductive particles when used as a circuit connection material. The adhesive composition of the present invention can be connected by direct contact of circuit electrodes facing each other at the time of connection, but more stable connection can be obtained when it contains conductive particles. Examples of the conductive particles include metal particles such as Au, Ag, Ni, Cu, and solder, carbon, and the like. In order to obtain a sufficient pot life, the surface layer is preferably Au, Ag, or a platinum group noble metal, preferably Au. More preferred.

  Further, the surface of a transition metal such as Ni may be coated with a noble metal such as Au. In addition, the conductive layer described above is formed by coating or the like on non-conductive glass, ceramic, plastic (polystyrene, etc.), the outermost layer is precious metal, the core is plastic, and in the case of hot-melt metal particles, heating Since it has deformability by pressurization, it is preferable because the contact area with the electrode is increased at the time of connection and the reliability is improved.

  It is preferable to set it as 0.1-30 volume% with respect to 100 volume of adhesive composition, and, as for the usage-amount of electroconductive particle, it is more preferable to set it as 0.1-10 volume%. If this value is 0.1% by volume or more, conductivity can be obtained, and if it is 30% by volume or less, a short circuit of the circuit can be suppressed. The volume% is determined based on the volume of each component before curing at 23 ° C., but the volume of each component can be converted from weight to volume using specific gravity.

  The adhesive composition of the present invention may be used in combination with a sensitizer for the purpose of improving the base generation efficiency of the photobase generator. As a sensitizer to be used, a known singlet sensitizer and triplet sensitizer can be used as long as they do not adversely affect the curable composition. For example, aromatic compound derivatives such as naphthalene, anthracene, and pyrene, carbazole derivatives, benzophenone derivatives, thioxanthone derivatives, and coumarin derivatives are preferably used. The amount of the sensitizer used is required to refer to the absorption wavelength and molar extinction coefficient of the sensitizer, but is generally preferably 0.01 to 5 parts by weight with respect to 1 part by weight of the imidazolium salt compound. 0.1 to 2 parts by weight is particularly preferred. If the sensitizer is 0.01 parts by weight or more, the effect of improving the light absorption efficiency can be obtained, and if it is 5 parts by weight or less, a situation where light does not reach the entire curable composition can be prevented.

  In the adhesive composition of the present invention, a silane coupling agent having a functional group such as an epoxy group, a mercapto group, an amino group, or an imidazole group in the skeleton, a tetraalkoxy titanate derivative or a polysiloxane is used for the purpose of further improving the adhesive strength. A coupling agent typified by a dialkyl titanate derivative can also be contained. Furthermore, a filler, a softener, an accelerator, an anti-aging agent, a colorant, a flame retardant, and a thixotropic agent can also be contained.

  In the adhesive composition of the present invention, (C) the basic compound generated by light irradiation from the photobase generator promotes the curing of the epoxy resin and the thiol compound, thereby promoting the reaction of the entire adhesive composition, As a result, the low temperature fast curability is improved. Furthermore, by including a thiol compound having one or more ester bonds in the molecule, it is possible to provide an adhesive composition having excellent adhesiveness.

  The circuit terminal connection method of the present invention includes a first circuit member having a first connection terminal and a second circuit member having a second connection terminal, the first connection terminal and the second connection terminal. Are arranged opposite to each other, and the connection material of the present invention (preferably a film-like adhesive) is interposed between the first connection terminal and the second connection terminal arranged opposite to each other, and the first connection arranged oppositely. Only the terminal and the second connection terminal are electrically connected. As such a circuit member, a chip component such as a semiconductor chip, a resistor chip or a capacitor chip, a substrate such as a printed circuit board, or the like is used. The circuit member is usually provided with a large number of connection terminals (or a single connection terminal in some cases).

  In order to obtain better electrical connection, it is preferable that at least one surface of the circuit electrode (connection terminal) is made of a metal selected from gold, silver, tin, and a platinum group. The surface layer is selected from gold, silver, platinum group, or tin, and these may be used in combination. Moreover, it is good also as a multilayer structure combining several metals like copper / nickel / gold.

  As a connection method, after arranging an adhesive composition on a first circuit member having a first connection terminal, after irradiating light from above the adhesive composition, it has a second connection terminal. The second circuit member can be disposed to face and pressurize while heating, and can be bonded by sequentially performing light irradiation, heating and pressurization.

In the case where the first circuit member is a transparent substrate from the ultraviolet region to the visible region, after the adhesive composition is disposed on the first circuit member having the first connection terminal, the second circuit member A second circuit member having a connection terminal can be disposed oppositely, and can be bonded even if light irradiation is performed from below the first circuit member simultaneously with heating and pressurization from the second circuit member. The curing condition is usually 1 to 120 seconds at 100 to 200 ° C. under a pressure of 0.1 to 10 MPa in the case of heating, but is not limited thereto. The light irradiation is preferably in the wavelength range of 150 to 750 nm, and a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, or a metal halide lamp can be used. Although it is 0.01-10 J / cm < ² >, it is not limited to this.

  The adhesive composition of the present invention can be used in the form of a paste when it is liquid at room temperature (25 ° C.). In the case of a solid at room temperature (25 ° C.), in addition to heating, it may be pasted using a solvent. The solvent that can be used is not particularly limited as long as it does not adversely affect the curability and exhibits sufficient solubility, but a solvent having a boiling point of 50 to 150 ° C. at normal pressure is preferable. When the boiling point is 50 ° C. or higher, volatilization when left at room temperature (25 ° C.) can be prevented, and use in an open system is possible. Moreover, if a boiling point is 150 degrees C or less, the removal of a solvent will become easy.

  The adhesive composition of the present invention can be used in the form of a film. A solution in which a solvent or the like is added to the adhesive composition as necessary is applied onto a peelable substrate such as a fluororesin film, a polyethylene terephthalate film, or a release paper, or a substrate such as a nonwoven fabric is impregnated with the solution. It can be placed on a peelable substrate and used as a film after removing the solvent and the like. Use in the form of a film is more convenient from the viewpoint of handleability.

  Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

(Synthesis of amine imide)
P-Nitrobenzoic acid methyl ester (2.00 g, 11 mmol), N, N-dimethylhydrazine (0.66 g, 11 mmol), phenylglycidyl ether (1.66 g, 11 mmol), tert- Butanol (15.0 g) was added, stirred for 10 hours at 50 ° C. while feeding nitrogen gas, and further stirred for 48 hours at room temperature (25 ° C.). As a result, a white precipitate was formed. The obtained precipitate was filtered off, washed twice with ethyl acetate, and dried with a vacuum dryer (device name: LHV-112, manufactured by Tabai) to obtain an amine imide compound. The yield was 3.67 g, and the yield was 85%.

(Synthesis of imidazolium salt)
In a 100 ml three-necked flask, p-nitrophenacyl bromide (2.00 g, 8.2 mmol) was dissolved in acetone (20 g), and 1,2-dimethylimidazole (0 g) dissolved in acetone (5 g) was dissolved therein. .79 g, 8.2 mmol) was slowly added, and then stirred at room temperature (25 ° C.) for 2 hours to precipitate white crystals. The obtained crystals were filtered, washed twice with acetone, and then dried under vacuum at 60 ° C. for 5 hours to obtain an imidazolium bromide salt (yield 2.62 g). The above-mentioned imidazole bromide salt (2.00 g, 5.8 mmol) was dissolved in a methanol / water (15 g / 15 g) solution, and tetraphenylborate sodium salt (2.01 g) dissolved in water (5.0 g). 5.8 mmol) solution was added slowly.
A white slurry-like precipitation was observed with the addition, and the mixture was further stirred at room temperature (25 ° C.) for 5 hours. The obtained precipitate was filtered, dissolved in acetone (20 g) and recrystallized to obtain the target imidazolium tetraphenylborate (imidazolium salt) (yield 3.23 g).
In addition, all stirring was performed with the magnetic stirrer (F202SC, the Fine company make), and temperature control was performed with the oil bath (device name: FWB-240, the Fine company make).

(Synthesis of quaternary ammonium salt 1)
In a 100 ml three-necked flask, p-nitrophenacyl bromide (2.00 g, 8.2 mmol) was dissolved in acetone (20 g), and N, N-dimethylbenzylamine (5 g) was dissolved in acetone (5 g). A solution of 1.10 g, 8.2 mmol) was slowly added, and then stirred at room temperature (25 ° C.) for 2 hours to precipitate white crystals. This was filtered, washed twice with acetone, and then dried under vacuum at 60 ° C. for 5 hours to obtain ammonium bromide salt 1 (yield 2.73 g). The ammonium bromide salt 1 (2.00 g, 5.3 mmol) was dissolved in a methanol / water (15 g / 15 g) solution in a 200 ml three-necked flask, and methanol / water (2.5 g / 2. A solution of sodium tetraphenylborate (1.84 g, 5.3 mmol) dissolved in 5 g) was added slowly. A white slurry-like precipitation was observed with the addition, and the mixture was further stirred at room temperature (25 ° C.) for 5 hours. This was filtered, dissolved in acetone (20 g) and recrystallized to obtain the desired quaternary ammonium salt (yield 2.98 g).
(Synthesis of quaternary ammonium salt 2)
2- (Bromoacetyl) naphthalene (3.00 g, 12.0 mmol) and methyl ethyl ketone (30 g) were added to a 200 ml three-necked flask, and 1,8-diaza-bicyclo (dissolved in methyl ethyl ketone (10 g) was added thereto. A solution of 5,4,0) -undecene-7 (1.83 g, 12.0 mmol) was slowly added, followed by stirring at 0 ° C. for 4 hours to precipitate white crystals. This was filtered, washed twice with acetone, and then dried under vacuum at 60 ° C. for 5 hours to obtain ammonium bromide salt 2 (yield 3.15 g).
Ammonium bromide salt 2 (3.00 g, 7.5 mmol) is dissolved in a methanol / water (50 g / 50 g) solution in a 200 ml three-necked flask, and dissolved in methanol / water (5 g / 5 g). A solution of tetraphenylborate sodium salt (2.56 g, 7.5 mmol) was added slowly. A white slurry-like precipitation was observed with the addition, and the mixture was further stirred at room temperature for 5 hours. This was filtered, dissolved in acetone (20 g) and recrystallized to obtain the desired quaternary ammonium salt 2 (yield 3.80 g).

(Synthesis of carbamate)
2,4-dinitrobenzyl alcohol (2.00 g, 10 mmol) and 1,8-diaza-bicyclo (5,4,0) undecene-7 (0.10 g, 0.6 mmol) in a 100 ml three-necked flask, Tetrahydrofuran (20 g) was added, and cyclohexyl isocyanate (1.27 g, 10 mmol) was added dropwise at room temperature (25 ° C.). After completion of the dropwise addition, the mixture was stirred at room temperature (25 ° C.) for 48 hours, and a white precipitate was formed. This was filtered off, recrystallized with ethyl acetate, and dried with a vacuum dryer to obtain a carbamate compound. The yield was 2.23 g and the yield was 68%.

(Synthesis of oxime ester)
In a 100 ml three-necked flask, 9-fluorenone oxime (2.00 g, 10 mmol) and pyridine (0.80 g, 10 mmol) were dissolved in 20 g of tetrahydrofuran, and diethylcarbamoyl chloride (1.36 g, 10 mmol) was dissolved in an ice bath. It was added dropwise while cooling. After completion of the dropwise addition, the mixture was stirred at room temperature (25 ° C.) for 24 hours, and a white precipitate was formed. When 200 g of water was added thereto, a pale yellow precipitate was deposited. This was filtered off, recrystallized with acetone, and dried with a vacuum dryer to obtain an oxime ester compound. The yield was 2.58 g and the yield was 88%.

(Examples 1-12)
As the thermoplastic resin, a phenoxy resin and a urethane resin were used. Methyl ethyl ketone (product name: 2-butanone, manufactured by Wako Pure Chemical Industries, Ltd., purity 99) in which 40 g of phenoxy resin (PKHC, trade name of Union Carbide, average molecular weight 45,000) is put in a glass container. %) Was dissolved in 60 g to obtain a solution having a solid content of 40% by weight. The urethane resin is composed of 450 parts by weight of polybutylene adipate diol having an average molecular weight of 2000 (product name: polybutylene adipate diol, manufactured by Aldrich) and polyoxytetramethylene glycol having an average molecular weight of 2000 (product name: polyoxytetramethylene glycol, Aldrich) 450 parts by weight, 1,4-butylene glycol (product name: 1,4-butylene glycol, Aldrich) 100 parts by weight methyl ethyl ketone (product name: 2-butanone, Wako Pure Chemical Industries, Ltd.) The product was obtained by dissolving in 4000 parts by weight of a product (purity 99%), adding 390 parts by weight of diphenylmethane diisocyanate (product name: diphenylmethane diisocyanate, manufactured by Aldrich) and reacting at 70 ° C. for 60 minutes. In addition, temperature control at this time was performed by an oil bath (device name: FWB-240, manufactured by Fine). It was 120,000 when the weight average molecular weight of the obtained urethane resin was measured by the gel permeation chromatography method (GPC).
Phenol novolac type epoxy resin (Epicoat 152, trade name of Japan Epoxy Resin Co., Ltd.) as the epoxy resin (A), pentaerythritol tetrakisthiopropionate (PETP, manufactured by Tokyo Chemical Industry Co., Ltd.) or Isocyan as the thiol compound (B) Nurate modified thiol compound (THEIC-BMPA, Sakai Chemical Co., Ltd. product name), 3-glycidoxypropyltrimethoxysilane (SZ6040, trade name of Toray Dow Corning Silicone Co., Ltd.) as a silane coupling agent, photobase generation The compounds shown in Table 1 were used as the agent (C). Further, a nickel layer having a thickness of 0.2 μm is provided on the surface of a particle having polystyrene as a nucleus, and a gold layer having a thickness of 0.02 μm is provided outside the nickel layer, and the conductive material has an average particle diameter of 4 μm and a specific gravity of 2.5. Particles were made.

  It mix | blends as shown in Table 1 by solid weight ratio, Furthermore, 1.5 volume% of electroconductive particles are mix-dispersed, and it applies to a fluororesin film of 80 micrometers in thickness (apparatus name: SNC-S3.0, Yasui Seiki). And a film adhesive having an adhesive layer thickness of 20 μm was obtained by hot air drying at 70 ° C. for 10 minutes.

(Measurement of adhesive strength and connection resistance)
Using the film-like adhesive obtained by the above manufacturing method, a flexible circuit board (FPC) having 500 copper circuits having a line width of 50 μm, a pitch of 100 μm, and a thickness of 18 μm, and a thin layer of 0.2 μm of indium oxide (ITO) The formed glass (thickness 1.1 mm, surface resistance 20Ω / □) was heated and pressurized at 140 ° C. and 3 MPa for 30 seconds to be connected over a width of 2 mm.
At this time, the adhesive surface of the film-like circuit connecting material is preliminarily connected to the ITO glass by heating and pressurizing at 70 ° C. and 0.5 MPa for 3 seconds, and then the fluororesin film is peeled off to form the circuit connecting composition. The film surface was irradiated with ultraviolet rays of 2.0 J / cm ² using an ultraviolet irradiation device (USHIO INC.) Having a high-pressure mercury lamp. Then, it connected with FPC which is another to-be-adhered body, and produced the connection body. The resistance value between adjacent circuits of this connection body was measured with a multimeter (device name: TR6848, manufactured by Advantest) immediately after bonding and after being held in a high-temperature and high-humidity bath at 85 ° C. and 85% RH. The resistance value was shown as an average of 37 resistances between adjacent circuits.

  Moreover, the adhesive strength of this connection body was measured by a 90-degree peeling method according to JIS-Z0237 and evaluated. Here, Tensilon UTM-4 (peeling speed 50 mm / min, 25 ° C.) manufactured by Toyo Baldwin Co., Ltd. was used as a measuring device for adhesive strength.

(Comparative Example 1)
A film-like adhesive was prepared in the same manner as in Example 3 except that 1,2-dimethylimidazole was used in place of the imidazolium salt as the photobase generator (C). Was made.

(Comparative Example 2)
Similar to Example 4 except that p-xylenedithiol (SH equivalent 85, solid weight ratio 25) having an SH equivalent of 85 and having no ester bond in the molecule was used instead of PETP which is a thiol compound (B). A film-like adhesive was prepared with the above composition, and a connection body was prepared in the same manner as in Example 4.

  Table 2 shows the results of measurement of the adhesive strength and connection resistance of the connection body performed as described above.

  The adhesive compositions obtained in Examples 1 to 12 had good connection resistance and adhesion at a heating temperature of 140 ° C. immediately after adhesion and after being held in a high-temperature and high-humidity tank at 85 ° C. and 85% RH for 168 hours. It was found to show strength and good properties. On the other hand, in Comparative Example 1 in which 1,2-dimethylimidazole was added instead of the photobase generator, curing progressed during drying (70 ° C., 10 minutes) during film production, and a connection body could not be obtained. . Moreover, in Comparative Example 2 using a thiol compound having no ester bond in the molecule, the connection resistance value immediately after adhesion is high, and after holding in a high-temperature and high-humidity tank at 85 ° C. and 85% RH, it is abrupt. An increase in connection resistance and a decrease in adhesive strength became apparent.

(Example 13)
The film adhesive obtained in Example 7 was vacuum packaged and allowed to stand at 40 ° C. for 3 days, and then FPC and ITO were thermocompression bonded at 140 ° C., 3 MPa, 30 s in the same manner as in Example 7. It was. As a result of measuring the adhesive strength and connection resistance of the connected body as described above, it was found that the adhesive strength was 790 N / m and the connection resistance was 1.7Ω, which was excellent in storage stability.

Claims (8)

(A) an epoxy resin, (B) a thiol compound having one or more ester bonds in the molecule, (C) a photobase generator that generates a base by light irradiation and conductive particles ,
(B) The thiol compound is trimethylolpropane tristhioglycolate, pentaerythritol tetrakisthioglycolate, trimethylolpropane tristhiopropionate, pentaerythritol tetrakisthiopropionate, represented by the following general formulas (1) and (2): An adhesive composition for circuit connection, which is at least one compound selected from the group of compounds shown .

(In general formulas (1) and (2), m and n each independently represents an integer of 1 to 5) The adhesive composition for circuit connection according to claim 1, wherein the (B) thiol compound is a compound represented by the general formula (1) or (2) . (C) The photobase generator is one or more compounds selected from the group consisting of amine imide derivatives, imidazolium salt derivatives, quaternary ammonium salt derivatives, carbamic acid ester derivatives, oxime ester derivatives, and α-aminoketone derivatives. The adhesive composition for circuit connection according to claim 1 or 2, characterized in that: Furthermore, the adhesive composition for circuit connections as described in any one of Claims 1 thru | or 3 containing a thermoplastic resin. The adhesive composition for circuit connection according to claim 4, wherein the thermoplastic resin is selected from phenoxy resin, polyester resin, polyurethane resin, polyester urethane resin, butyral resin, and acrylic resin. The first circuit member having the first connection terminal and the second circuit member having the second connection terminal are arranged to face the first connection terminal and the second connection terminal, and The adhesive composition for circuit connection according to any one of claims 1 to 5 is interposed between a first connection terminal and a second connection terminal arranged opposite to each other, and the first connection arranged opposite to the first connection terminal. A circuit terminal connection structure in which only the terminal and the second connection terminal are electrically connected. After arrange | positioning the adhesive composition for circuit connections as described in any one of Claims 1 thru | or 5 on the 1st circuit member which has a 1st connection terminal, and performing light irradiation from the upper direction of an adhesive composition The second circuit member having the second connection terminal is disposed oppositely, and the first connection terminal and the second connection terminal that are disposed opposite to each other by applying pressure while heating are electrically connected to each other. Connection method. A first circuit member having a first connection terminal and a second circuit member having a second connection terminal are disposed so that the first connection terminal and the second connection terminal are opposed to each other, and the opposed arrangement is performed. The adhesive composition for circuit connection according to any one of claims 1 to 5 is interposed between the first connection terminal and the second connection terminal, and the facing is performed by applying pressure while heating simultaneously with light irradiation. A circuit terminal connection method for electrically connecting only the arranged first connection terminal and second connection terminal.