JP5251393B2 - Adhesive composition, adhesive for circuit connection, and connection body using the same - Google Patents

Description

  The present invention relates to an adhesive composition, an adhesive for circuit connection, and a connection body using the same.

In the semiconductor element and the liquid crystal display element, various adhesives are conventionally used for the purpose of bonding various members in the element. The properties required for adhesives vary widely, including adhesiveness, heat resistance, reliability in high temperature and high humidity conditions, and the like. In addition, the adherends used for adhesion include organic substrates such as printed wiring boards and polyimides, metals such as copper and aluminum, and substrates having various surface states such as ITO, SiN, and SiO _2. Is used. For this reason, it is necessary to molecularly design the adhesive in accordance with each adherend.

  Conventionally, a thermoplastic resin has been used as a main component as an adhesive for the semiconductor element and the liquid crystal display element (see, for example, Patent Document 1), but the thermoplastic adhesive has problems in reliability and heat resistance. . Therefore, a thermosetting resin using an epoxy resin that exhibits high adhesiveness and high reliability has become the mainstream (see, for example, Patent Document 2). As such thermosetting resins, those containing a curing agent such as an epoxy resin, a phenol resin having reactivity with the epoxy resin, and a thermal latent catalyst for promoting the reaction between the epoxy resin and the curing agent are generally used. . The heat latent catalyst is an important factor for determining the curing temperature and the curing rate, and various compounds have been used from the viewpoint of storage stability at room temperature and curing rate during heating. As for the curing conditions in the actual process, desired adhesiveness is obtained by curing at a temperature of 170 to 250 ° C. for 1 to 3 hours.

  In recent years, with high integration of semiconductor elements and high definition of liquid crystal elements, the pitch between elements and between wirings has been reduced. For this reason, when heat processing is performed on said conditions, there exists a possibility of having a bad influence on a peripheral member by the heating at the time of hardening. In order to further reduce the cost, it is necessary to improve the throughput, and adhesion at a low temperature (100 to 170 ° C.), a short time (within 1 hour, preferably within a few seconds), in other words, “low temperature rapid curing”. Is required. In order to achieve this low temperature rapid cure, a thermal latent catalyst with low activation energy may be used, but in that case, it is very difficult for the adhesive to have storage stability near room temperature. It has been known.

Recently, a radical curable adhesive using an acrylate derivative or a methacrylate derivative (hereinafter referred to as “(meth) acrylate derivative”) in combination with a peroxide as a radical polymerization initiator has attracted attention (for example, Patent Document 3). 4). The radical curable adhesive can be cured in a short time because radicals which are reactive species are highly reactive. In particular, when a compound having two or more (meth) acrylate derivatives in the molecule is used, a cross-linked structure is formed after curing, so that adhesion and connection reliability can be improved.
Japanese Patent Laid-Open No. 04-62714 Japanese Patent Laid-Open No. 01-113480 JP 2002-203427 A International Publication No. 98/044067 Pamphlet

  However, the conventional radical curable adhesives described in Patent Documents 3, 4 and the like have a problem that the adhesive strength is inferior to that of an epoxy curable adhesive because the curing shrinkage during curing is large.

  The present invention provides an adhesive composition capable of obtaining sufficient adhesion and connection reliability even when cured at a low temperature in a short time, and an adhesive for circuit connection and a connection body using the same. The purpose is to provide.

  In view of the above circumstances, the present invention provides (a) a thermoplastic resin, (b) a radical polymerizable compound having two or more (meth) acryloyl groups in the molecule, (c) a radical polymerization initiator, and (d) heating. An adhesive composition comprising a silane coupling agent having a functional group that generates isocyanate is provided.

  According to such an adhesive composition, sufficient adhesiveness and connection reliability can be obtained even when cured at a low temperature in a short time.

  (D) The silane coupling agent having a functional group that generates isocyanate upon heating is preferably a compound represented by the following general formula (I) or a compound represented by the following general formula (II).

（式（Ｉ）中、ｍ、ｎは独立に１〜３の整数、Ｒ_１は水素原子、メチル基又はエチル基、Ｒ_２、Ｒ_３は、それぞれ任意の一価の有機官能基を表す。）

(In formula (I), m and n are each independently an integer of 1 to 3, R ₁ is a hydrogen atom, a methyl group or an ethyl group, and R ₂ and R ₃ each represents an arbitrary monovalent organic functional group. )

（式（ＩＩ）中、ｍ、ｎは独立に１〜３の整数、Ｒ_４は水素原子、メチル基又はエチル基、Ｒ_５、Ｒ_６、Ｒ_７は独立に水素原子又は任意の一価の有機官能基を表す。）

(In the formula (II), m and n are each independently an integer of 1 to 3, R ₄ is a hydrogen atom, a methyl group or an ethyl group, R ₅ , R ₆ and R ₇ are independently a hydrogen atom or any monovalent group. Represents an organic functional group.)

  The adhesive composition of the present invention comprises (a) 50 to 250 parts by mass of a radically polymerizable compound having 2 or more (meth) acryloyl groups in the molecule with respect to 100 parts by mass of the thermoplastic resin. c) It is preferable to contain 0.05-30 mass parts of radical polymerization initiators, and (d) 0.2-5 mass parts of silane coupling agents which have a functional group which produces | generates isocyanate by heating.

  The adhesive composition of the present invention preferably further contains (e) conductive particles in an amount of 0.1 to 30% by volume based on the total amount of the adhesive composition.

  The present invention is an adhesive for circuit connection that is interposed between substrates having circuit electrodes facing each other, and is used for bonding the substrates so that the circuit electrodes facing each other are electrically connected to each other, Provided is an adhesive for circuit connection comprising the adhesive composition of the present invention.

  Since such an adhesive for circuit connection uses the adhesive composition of the present invention, sufficient adhesiveness and connection reliability can be obtained even when cured at a low temperature in a short time.

  In the present invention, a first substrate having a first circuit electrode and a second substrate having a second circuit electrode are arranged so that the first circuit electrode and the second circuit electrode face each other. Then, the adhesive for circuit connection of the present invention is interposed between the first substrate and the second substrate arranged to face each other, and heated and pressurized to connect the first circuit electrode and the second circuit electrode. Provided is a connection body that is electrically connected.

  Since this connection body uses the adhesive for circuit connection of the present invention, it has sufficiently high adhesiveness and connection reliability.

  ADVANTAGE OF THE INVENTION According to this invention, even when it hardens | cures at low temperature for a short time, the adhesive composition which makes it possible to acquire sufficient adhesiveness and connection reliability, the adhesive agent for circuit connection using the same, and connection The body is provided.

  The adhesive composition of the present invention comprises (a) a thermoplastic resin, (b) a radical polymerizable compound having two or more (meth) acryloyl groups in the molecule, (c) a radical polymerization initiator, and (d) heating. A silane coupling agent having a functional group for generating an isocyanate.

(A) As a thermoplastic resin, a well-known thing can be used without a restriction | limiting in particular. Examples of such a resin include polyimide, polyamide, phenoxy resins, poly (meth) acrylates, polyimides, polyurethanes, polyesters, polyester urethanes, and polyvinyl butyrals. These can be used alone or in admixture of two or more.
Furthermore, these resins may contain a siloxane bond or a fluorine substituent. These can be suitably used as long as the resins to be mixed are completely compatible with each other or microphase separation occurs and becomes cloudy.
The larger the molecular weight of the resin, the easier it is to obtain film formability, and the melt viscosity that affects the fluidity as an adhesive can be set over a wide range. The molecular weight is not particularly limited, but a 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, the film formability tends to be satisfied, and if it is 150,000 or less, the tendency for compatibility with other components to deteriorate can be prevented.

In addition, in this specification, a weight average molecular weight means what was measured using the calibration curve by a standard polystyrene by the gel permeation chromatography method (GPC) on the following conditions.
<GPC conditions>
Equipment used: Hitachi L-6000 (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.]

(B) As a radically polymerizable compound having two or more (meth) acryloyl groups in the molecule, any known compound may be used without particular limitation as long as it has two or more (meth) acryloyl groups in the molecule. can do.
Specific examples include oligomers such as epoxy (meth) acrylate oligomers, urethane (meth) acrylate oligomers, polyether (meth) acrylate oligomers, polyester (meth) acrylate oligomers, trimethylolpropane tri (meth) acrylate, polyethylene glycol diesters. (Meth) acrylate, polyalkylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, isocyanuric acid modified bifunctional (meth) acrylate, isocyanuric acid modified trifunctional (meth) Examples thereof include polyfunctional (meth) acrylate compounds such as acrylate and 2,2′-di (meth) acryloyloxydiethyl phosphate. These compounds may be used alone or in combination as required.

  (B) The addition amount of the radically polymerizable compound having two or more (meth) acryloyl groups in the molecule is preferably 50 to 250 parts by weight, more preferably 100 parts by weight of the thermoplastic resin (a). Is 60 to 150 parts by mass. If the addition amount is 50 parts by mass or more, the heat resistance after curing is further improved. Moreover, if it is 250 mass parts or less, when using as a film, it can prevent that film formability falls.

(C) As the radical polymerization initiator, known compounds such as conventionally known peroxides and azo compounds can be used. From the viewpoint of stability, reactivity, and compatibility, the half-life temperature for 1 minute is used. Is preferably a peroxyester derivative or diacyl peroxide compound having a weight average molecular weight of 180 to 1,000. The above-described method can be used as a method for measuring the weight average molecular weight.
Specific examples thereof include cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxynodecanoate, and t-hexyl. Peroxyneodecanoate, t-butylperoxyneodecanoate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5- Dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyneo Heptanoate, t-amylperoxy-2-ethylhexanoate, di-t-butylperoxyhexahydroterephthalate Tate, t-amylperoxy-3,5,5-trimethylhexanoate, 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, t-amylperoxyneodecanoate, t-amylperoxy-2-ethylhexanoate, 2,2′-azobis-2,4-dimethylvaleronitrile, 1,1 ′ -Azobis (1-acetoxy-1-phenylethane), 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), dimethyl-2,2'-azobisiso Butyronitrile, 4,4′-azobis (4-cyanovaleric acid), 1,1′-azobis (1-cyclohexanecarbonitrile), t-hexylperoxyisopropyl monocarbonate Bonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di (3-methyl Benzoylperoxy) hexane, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxybenzoate, Dibutylperoxytrimethyladipate, t-amylperoxynormal octoate, t-amylperoxyisononanoate, t-amylperoxybenzoate, dibenzoyl peroxide, dilauroyl peroxide, di-t-butylperoxyhexahydro Examples include terephthalate It is. These compounds may be used alone or as a mixture of two or more compounds.

  (C) The addition amount of the radical polymerization initiator is preferably 0.05 to 30 parts by mass, and preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the (a) thermoplastic resin. If the addition amount is 0.05 parts by mass or more, insufficient curing can be prevented, and if the addition amount is 30 parts by mass or less, deterioration in standing stability can be prevented.

  (D) As a silane coupling agent having a functional group that generates isocyanate upon heating, a silane compound having a group represented by the following general formula (i) or (ii) can be preferably used, and more preferably. Can be a compound represented by the following general formula (I) or (II).

（式中、ｍ、ｎは独立に１〜３の整数、Ｒ_１は、水素原子、メチル基又はエチル基、Ｒ_２、Ｒ_３は、それぞれ任意の一価の有機官能基、Ｒ_４は水素原子、メチル基又はエチル基、Ｒ_５、Ｒ_６、Ｒ_７は独立に水素原子又は任意の一価の有機官能基を表す。）

(In the formula, m and n are each independently an integer of 1 to 3, R ₁ is a hydrogen atom, a methyl group or an ethyl group, R ₂ and R ₃ are each an arbitrary monovalent organic functional group, and R ₄ is hydrogen. Atom, methyl group or ethyl group, R ₅ , R ₆ , R ₇ independently represent a hydrogen atom or any monovalent organic functional group.)

  Specific examples of the compound represented by the general formula (I) or (II) include the compounds shown below. These compounds may be used alone or as a mixture of two or more compounds.

（Ｅｔは、エチル基を示す。）

(Et represents an ethyl group.)

  (D) The addition amount of the silane coupling agent having a functional group that generates isocyanate by heating is preferably 0.2 to 5 parts by mass, more preferably 100 parts by mass of the thermoplastic resin (a). It is 0.5-3 mass parts, More preferably, it is 1-2 mass parts. If the addition amount is less than 0.2 parts by mass, the desired addition effect tends not to be obtained, and if it exceeds 5 parts by mass, phase separation from the adhesive component tends to occur.

When the adhesive composition of the present invention is used for circuit connection, it is preferable to contain (e) conductive particles in order to impart conductivity or anisotropic conductivity to the adhesive.
(E) Examples of the conductive particles include metal particles such as Au, Ag, Ni, Cu, and solder, and carbon. Further, (e) the conductive particles may have non-conductive glass, ceramic, plastic or the like as a core, and the core, the metal, metal particles, or carbon may be coated on the core.
(E) In the case where the conductive particle is a plastic core and the core is coated with the above-mentioned metal, metal particle or carbon, or a hot-melt metal particle such as solder, it is deformable by heating and pressurization. It is preferable because it absorbs variation in thickness, increases the contact area with the electrode, and improves reliability.

  Further, fine particles obtained by coating the surface of these conductive particles with a polymer resin or the like may be used as (e) conductive particles. Such fine particles suppress short-circuiting due to contact between particles when the amount of conductive particles is increased, and can improve insulation between electrode circuits. Therefore, these can be used alone or mixed with conductive particles as appropriate. Can be used.

(E) The average particle diameter of the conductive particles is preferably 1 to 18 μm from the viewpoint of dispersibility and conductivity. (E) The amount of conductive particles added is not particularly limited, but is preferably 0.1 to 30% by volume, and preferably 0.1 to 10% by volume based on the total amount of the adhesive composition. More preferred.
If this value is less than 0.1% by volume, the conductivity tends to be inferior, and if it exceeds 30% by volume, a short circuit tends to occur. 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. In addition, do not dissolve or swell the component in a graduated cylinder, etc., but put in a suitable solvent (water, alcohol, etc.) that wets the component well. You can ask for it.

  To the adhesive composition of the present invention, an adhesion assistant such as a coupling agent represented by a phosphate ester derivative, an adhesion improver, and a leveling agent may be appropriately added. Specifically, a compound represented by the following general formula can be suitably added. These compounds may be used alone or as a mixture of two or more compounds.

（ここでＲ８は水素、メチル基、ｎは１〜１０の整数、ｍは１又は２を示す。）

(Here, R8 is hydrogen, a methyl group, n is an integer of 1 to 10, and m is 1 or 2.)

  In the adhesive composition of the present invention, for the purpose of improving the crosslinking rate, in addition to the radically polymerizable compound having two or more (b) (meth) acryloyl groups, an allyl group, a maleimide group, a vinyl group, etc. You may add suitably the compound which has a functional group superposed | polymerized by an active radical. Specific examples thereof include N-vinylimidazole, N-vinylpyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylcaprolactam, 4,4′-vinylidenebis (N, N-dimethylaniline), N-vinyl. Examples include acetamide, N, N-dimethylacrylamide, N-isopropylacrylamide, N, N-diethylacrylamide, and acrylamide.

  A monofunctional (meth) acrylate may be added to the adhesive composition of the present invention for the purpose of improving fluidity. Specific examples thereof include pentaerythritol (meth) acrylate, 2-cyanoethyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, 2- (2 -Ethoxyethoxy) ethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-hexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate , Isobornyl (meth) acrylate, isodecyl (meth) acrylate, isooctyl (meth) acrylate, n-lauryl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-phenoxy Chill (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2- (meth) acryloyloxyethyl phosphate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, (meth) acryloylmorpholine may be mentioned.

A rubber component may be added to the adhesive composition of the present invention for the purpose of stress relaxation and adhesion improvement. Specific examples thereof include polyisoprene, polybutadiene, carboxyl group-terminated polybutadiene, hydroxyl-terminated polybutadiene, 1,2-polybutadiene, carboxyl-terminated 1,2-polybutadiene, hydroxyl-terminated 1,2-polybutadiene, acrylic rubber, and styrene-butadiene rubber. Hydroxyl group-terminated styrene-butadiene rubber, acrylonitrile-butadiene rubber, carboxyl group, hydroxyl group, (meth) acryloyl group or morpholine group-containing acrylonitrile-butadiene rubber, carboxylated nitrile rubber, hydroxyl group-terminated poly (oxypropylene), Examples include alkoxysilyl group-terminated poly (oxypropylene), poly (oxytetramethylene) glycol, polyolefin glycol, and poly-ε-caprolactone.
As the rubber component, a rubber component containing a cyano group or a carboxyl group, which is a highly polar group, in the side chain or terminal is preferable from the viewpoint of improving adhesiveness, and liquid rubber is more preferable from the viewpoint of improving fluidity. Specific examples thereof include a liquid acrylonitrile-butadiene rubber, a carboxyl group, a hydroxyl group, a liquid acrylonitrile-butadiene rubber containing a (meth) acryloyl group or a morpholine group at the polymer terminal, and a liquid carboxylated nitrile rubber, which is a polar group. The acrylonitrile content is preferably 10 to 60%. These compounds may be used alone or as a mixture of two or more compounds.

  In the adhesive composition of the present invention, for the purpose of imparting storage stability, t-butylpyrocatechol, t-butylphenol, p-methoxyphenol, 2,2,6,6-tetramethylpiperidine-1-oxy radical ( TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPOL) and other additives such as polymerization inhibitors may be added as appropriate.

The adhesive composition of the present invention can be used as a paste adhesive when it is liquid at room temperature (25 ° C.). In the case of a solid at room temperature, in addition to heating, it can be pasted using a solvent and used as a paste adhesive.
The solvent that can be used is not particularly limited as long as the reactivity with the adhesive composition and the additive is sufficiently small and exhibits sufficient solubility, but the boiling point at normal pressure is 50 to 150. Those having a temperature are preferred. If the boiling point is 50 ° C. or higher, volatilization when left at room temperature can be prevented, and it can also be used in an open system. Moreover, if a boiling point is 150 degrees C or less, it is easy to volatilize a solvent and it will not have a bad influence on the reliability after adhesion | attachment.

  The adhesive composition of the present invention can also be used as a film adhesive. The film adhesive is, for example, a solution obtained by adding a solvent or the like to the adhesive composition as necessary, on a peelable substrate such as a fluororesin film, a polyethylene terephthalate film, a release paper, or a non-woven fabric. It can be produced by impregnating the base material with the solution and placing the base material on the peelable base material and removing the solvent and the like. A film adhesive is more convenient from the viewpoint of handleability.

  The adhesive composition of the present invention can be bonded using heating and pressurization together. The heating temperature is not particularly limited, but is preferably 100 to 170 ° C. The pressure is not particularly limited as long as it does not damage the adherend, but is generally preferably 0.1 to 10 MPa. These heating and pressurization are preferably performed in the range of 0.5 seconds to 120 seconds.

  The adhesive composition of the present invention can be used as an adhesive for circuit connection for connecting different types of adherends having different thermal expansion coefficients. Specifically, it is used as a semiconductor element adhesive material typified by anisotropic conductive adhesive, silver paste, silver film, etc., circuit connection material, CSP elastomer, CSP underfill material, LOC tape, etc. Can do.

  In the connection body according to the present invention, the first circuit electrode and the second circuit electrode face each other between the first substrate having the first circuit electrode and the second substrate having the second circuit electrode. The first circuit electrode and the second circuit are arranged by interposing the circuit connecting adhesive of the present invention between the first substrate and the second substrate arranged to face each other and heating and pressing the adhesive. The electrode is electrically connected.

  As an adhesive for circuit connection, the anisotropic conductive film which consists of the adhesive composition of this invention containing (e) electroconductive particle is preferable.

  As the substrate for forming the circuit electrode, for example, inorganic materials such as semiconductors, glass and ceramics, organic materials such as polyimide and polycarbonate, and combinations of these composites such as glass / epoxy can be applied.

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

(Synthesis of silane coupling agent 1)
25 g of 3-isocyanatopropyltriethoxysilane (product name: KBE9007, manufactured by Shin-Etsu Chemical Co., Ltd.) and 9.7 g of 3,5-dimethylpyrazole (manufactured by Tokyo Chemical Industry Co., Ltd.), methyl ethyl ketone (product name: 2-butanone) In addition to 50 g of Wako Pure Chemical Industries, Ltd., purity 99%), the mixture was heated to reflux for 120 minutes to obtain a silane coupling agent 1 represented by the following formula (IIa).

なお、ＦＴ−ＩＲによってイソシアネート基由来の吸収（２２７０ｃｍ^−１）の消失を確認することにより、反応の終結を確認した。また加熱還流の際の温度制御はオイルバス（装置名：ＨＯＢ−５０Ｄ，アズワン株式会社製）により行った。

In addition, the completion | finish of reaction was confirmed by confirming the loss | disappearance of absorption (2270cm < ^-1 >) derived from an isocyanate group by FT-IR. Moreover, the temperature control at the time of heating-refluxing was performed by an oil bath (device name: HOB-50D, manufactured by ASONE CORPORATION).

(Synthesis of silane coupling agent 2)
25 g of 3-isocyanatopropyltriethoxysilane (product name: KBE9007, manufactured by Shin-Etsu Chemical Co., Ltd.) and 8.7 g of butanone oxime (manufactured by Tokyo Chemical Industry Co., Ltd.), methyl ethyl ketone (product name: 2-butanone, Wako Pure Chemical Industries, Ltd.) In addition to 50 g (purity 99%), the mixture was heated to reflux for 4 hours to obtain a silane coupling agent 2 represented by the following formula (Ia).

なお、ＦＴ−ＩＲによってイソシアネート基由来の吸収（２２７０ｃｍ^−１）の消失を確認することにより、反応の終結を確認した。また、加熱還流の際の温度制御はオイルバス（装置名：ＨＯＢ−５０Ｄ，アズワン株式会社製）により行った。

In addition, the completion | finish of reaction was confirmed by confirming the loss | disappearance of absorption (2270cm < ^-1 >) derived from an isocyanate group by FT-IR. Moreover, temperature control at the time of heating and refluxing was performed by an oil bath (device name: HOB-50D, manufactured by AS ONE Corporation).

(Examples 1 and 2, Comparative Examples 1 and 2)
(A) Methyl ethyl ketone (product name: 2-butanone, Wako Pure Chemical Industries) in which 40 g of a phenoxy resin (product name: PKHC, manufactured by Union Carbide Corporation, weight average molecular weight 45,000) is placed as a thermoplastic resin in a glass container. Kogyo Co., Ltd., purity 99%) dissolved in 60 g to give a solution having a solid content of 40% by weight and a urethane resin prepared as follows.
450 parts by weight of polybutylene adipate diol having a weight 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, manufactured by Aldrich) 450 parts by weight, 100 parts by weight of 1,4-butylene glycol (product name: 1,4-butylene glycol, manufactured by Aldrich), methyl ethyl ketone (product name: 2-butanone, manufactured by Wako Pure Chemical Industries, Ltd., purity 99% ) In 4000 parts by weight, 390 parts by weight of diphenylmethane diisocyanate (product name: diphenylmethane diisocyanate, manufactured by Aldrich) was added and reacted at 70 ° C. for 60 minutes to obtain a urethane resin.
In addition, temperature control at this time was performed by an oil bath (device name: HOB-50D, manufactured by AS ONE Corporation). It was 100,000 when the weight average molecular weight of the obtained urethane resin was measured by the gel permeation chromatography method (GPC).

(B) As a radically polymerizable compound having two or more (meth) acryloyl groups in the molecule, isocyanuric acid EO-modified diacrylate (M-215, trade name, manufactured by Toagosei Co., Ltd.), urethane acrylate (AT-600, Kyoeisha) Chemical Co., Ltd. trade name) and bis [2- (methacryloyloxy) ethyl] phosphate (P-2M, Kyoeisha Chemical Co., Ltd. trade name) were used.
(C) As the radical polymerization initiator, t-hexyl peroxy-2-ethylhexanoate (Perhexyl O, a product name manufactured by NOF Corporation) was used.
(D) Silane coupling agents 1 and 2 synthesized by the above-described method were used as silane coupling agents having a functional group that generates isocyanate upon heating. Further, alkoxysilyl isocyanate (KBE9007, manufactured by Shin-Etsu Chemical Co., Ltd.) was used as a comparative silane coupling agent.
(E) Conductive particles produced as described below were used as the conductive particles.
By providing a nickel layer having a thickness of 0.2 μm on the surface of particles having polystyrene as a core, and providing a gold layer having a thickness of 0.02 μm on the outside of the nickel layer, a conductive material having an average particle diameter of 4 μm and a specific gravity of 2.5. Particles were made.

  The components (a) to (d) described above were blended at a solid weight ratio shown in Table 1, and (e) 1.5% by volume of conductive particles were blended and dispersed. This dispersion was applied to a fluororesin film having a thickness of 80 μm using a coating device (device name: SNC-S3.0, manufactured by Yasui Seiki Co., Ltd.), and dried with hot air at 70 ° C. for 10 minutes to form an adhesive layer. A film adhesive having a thickness of 20 μm was obtained.

[Measurement of connection resistance and adhesive strength]
A flexible circuit board (FPC) having 500 copper circuits having a line width of 25 μm, a pitch of 50 μm, and a thickness of 18 μm, and 0.5 μm of silicon nitride (SiN) or 0.2 μm, using the film-like adhesive obtained by the above-described manufacturing method. A glass (thickness 1.1 mm, surface resistance 20 Ω / □) on which a thin layer of indium oxide (ITO) was formed on the entire surface was heated using a thermocompression bonding apparatus (heating method: constant heat type, manufactured by Toray Engineering Co., Ltd.). Temporarily attached at 1 ° C. for 3 seconds. Thereafter, heating and pressurization at 160 ° C. and 3 MPa for 10 seconds were performed to connect over a width of 2 mm to produce a connection body.
The bonding strength (adhesive strength) to SiN or ITO immediately after bonding of this connector and after being held in a high-temperature and high-humidity bath at 80 ° C. and 95% RH for 240 hours after bonding (JIS-Z0237) Measured by a 90-degree peeling method according to the above. Here, Tensilon UTM-4 (peeling speed 50 mm / min, 25 ° C.) manufactured by Toyo Baldwin Co., Ltd. was used as an adhesive strength measuring device.
Moreover, the resistance value between adjacent circuits was measured with a multimeter (device name: TR6848, manufactured by Advantest Co., Ltd.) for the connection body in the case of using the glass having the ITO thin film formed on the entire surface. The resistance value is shown as an average (x + 3σ) of 150 resistances between adjacent circuits.

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

  The adhesive composition obtained when the silane coupling agent is added (Examples 1 and 2 and Comparative Example 2) has improved adhesive strength as compared with the case where the silane coupling agent is not added (Comparative Example 1). did.

Moreover, when the alkoxysilyl isocyanate which does not produce | generate isocyanate by heating was added to the adhesive composition (Comparative Example 2), although the adhesive force improved, connection resistance deteriorated.
When the silane coupling agent which produces | generates isocyanate by heating was added (Examples 1 and 2), the adhesive force improved without lowering the connection resistance, a good electrical connection was made, and the connection reliability was improved.

Claims (8)

  (A) a thermoplastic resin, (b) a radical polymerizable compound having two or more (meth) acryloyl groups in the molecule, (c) a radical polymerization initiator, and (d) a functional group that generates isocyanate upon heating. An adhesive composition containing a silane coupling agent. (D) The adhesive composition of Claim 1 whose silane coupling agent which has a functional group which produces | generates isocyanate by heating is a compound represented by the following general formula (I).

(In formula (I), m and n are each independently an integer of 1 to 3, R ₁ is a hydrogen atom, a methyl group or an ethyl group, and R ₂ and R ₃ each represents an arbitrary monovalent organic functional group. ) (D) The adhesive composition of Claim 1 whose silane coupling agent which has a functional group which produces | generates isocyanate by heating is a compound represented by the following general formula (II).

(In the formula (II), m and n are each independently an integer of 1 to 3, R ₄ is a hydrogen atom, a methyl group or an ethyl group, R ₅ , R ₆ and R ₇ are independently a hydrogen atom or any monovalent group. Represents an organic functional group.)   (A) 50 to 250 parts by mass of a radically polymerizable compound having 2 or more (meth) acryloyl groups in the molecule and 100 parts by mass of (c) a radical polymerization initiator with respect to 100 parts by mass of the thermoplastic resin. Adhesive composition as described in any one of Claims 1-3 which contains 0.2-5 mass parts of silane coupling agents which have a functional group which produces | generates isocyanate by 05-30 mass parts and (d) heating. object.   (E) Adhesive composition as described in any one of Claims 1-4 which further contains electroconductive particle 0.1-30 volume% on the basis of adhesive composition whole quantity. An adhesive for circuit connection that is interposed between substrates having circuit electrodes facing each other, and is used for bonding the substrates so that the circuit electrodes facing each other are electrically connected,
The adhesive for circuit connection which consists of an adhesive composition as described in any one of Claims 1-5. A first substrate having a first circuit electrode;
A second substrate having a second circuit electrode;
The first circuit electrode and the second circuit electrode are arranged so as to face each other,
The adhesive for circuit connection according to claim 6 is interposed between the first substrate and the second substrate which are arranged to face each other, and the first circuit electrode and the second circuit are heated and pressed. A connection body in which electrodes are electrically connected.   The connection body according to claim 7, wherein the first substrate having the first circuit electrode is a semiconductor element.