JP6645499B2 - Adhesive composition and connector - Google Patents

Description

  The present invention relates to an adhesive composition and a connector.

  2. Description of the Related Art In a semiconductor device or a liquid crystal display device, various adhesive compositions have conventionally been used as circuit connecting materials for the purpose of bonding various members in the device. The adhesive composition is required to have various properties such as adhesiveness, heat resistance, and reliability in a high temperature and high humidity state.

The adherends to be bonded are various surfaces formed from various materials, such as organic materials such as printed wiring boards and polyimide films, metals such as copper and aluminum, and metal compounds such as ITO, SiN and SiO _2. Having. Therefore, the adhesive composition is designed according to each adherend.

  As an adhesive composition for a semiconductor element or a liquid crystal display element, a thermosetting resin composition containing a thermosetting resin such as an epoxy resin having high adhesion and high reliability is known (for example, Patent Document 1). reference). Such an adhesive composition generally contains a curing agent such as an epoxy resin and a phenol resin that reacts with the epoxy resin, and a heat latent catalyst that promotes the reaction between the epoxy resin and the curing agent. Among them, the thermal latent catalyst is an important factor that determines the curing temperature and the curing speed. Therefore, various compounds are used as the heat latent catalyst from the viewpoints of storage stability at room temperature and a curing rate at the time of heating. This adhesive composition is generally cured by heating at a temperature of 170 to 250 ° C. for 1 to 3 hours to exhibit desired adhesiveness.

  Also, a radical-curable adhesive containing a (meth) acrylate derivative and a peroxide has attracted attention (for example, see Patent Document 2). The radical-curable adhesive is advantageous in that it can be cured in a short time because radicals that are reactive species have high reactivity.

JP-A-1-113480 WO 98/44067

  With the recent high integration of semiconductor elements and high definition of liquid crystal elements, the pitch between elements and between wirings has been narrowing, and heating during curing for circuit connection may adversely affect peripheral members. It is getting higher.

  Furthermore, in order to reduce costs, it is necessary to improve the throughput, and there is a need for the development of an adhesive composition that cures at a lower temperature and in a shorter time, in other words, an adhesive composition that cures at a lower temperature and faster. Have been.

  In order to achieve low-temperature rapid curing of the adhesive composition, for example, in the thermosetting resin composition, a heat latent catalyst having a low activation energy may be used. It is very difficult to maintain storage stability.

  On the other hand, the radical-curable adhesive can achieve low-temperature rapid curing while having a practically satisfactory level of storage stability. However, even when a radical-curable adhesive is used, the radical-polymerizable compound in the adhesive almost reacts when cured at a lower temperature (for example, 140 ° C. or lower) than in the past. Nevertheless, the adhesive strength between the adherend and the adhesive may not be obtained. This is presumably because the interaction between the adherend and the adhesive was not sufficiently developed under the low temperature condition.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and has been made to adhere to an adherend even at a lower temperature (for example, 140 ° C. or lower) as compared with the conventional radical-curing adhesive. An object of the present invention is to provide an adhesive composition capable of sufficiently exhibiting adhesive strength with an agent.

  The present invention is an adhesive composition comprising (a) a thermoplastic resin, (b) a radical polymerizable compound, and (c) a radical polymerization initiator, wherein (b) the radical polymerizable compound is an isocyanate group. And a radical polymerizable compound having a structure in which an isocyanate group is generated by heating. According to such an adhesive composition, the adhesive strength between the adherend and the adhesive can be sufficiently exhibited even at a lower temperature (for example, 140 ° C. or lower) than in the past.

  The content of the radical polymerizable compound having an isocyanate group or the radical polymerizable compound having a structure in which an isocyanate group is generated by heating is based on 100 parts by mass of the total amount of (a) the thermoplastic resin and (b) the radical polymerizable compound. , 2 to 12 parts by mass. By setting the content within this range, the above-described effect is further increased.

  The adhesive composition of the present invention may further contain (d) conductive particles. Since the adhesive composition can be provided with conductivity or anisotropic conductivity by further containing conductive particles, the adhesive composition can be more suitably used as a circuit connection material. Further, the connection resistance between the circuit electrodes electrically connected via the adhesive composition can be more easily reduced.

  The present invention also includes a first circuit member having a first circuit electrode formed on a main surface of a first circuit board, and a second circuit electrode formed on a main surface of a second circuit board, A second circuit member disposed so that the second circuit electrode and the first circuit electrode face each other, and a first circuit member provided between the first circuit member and the second circuit member. And a connecting member for electrically connecting the second circuit member and the second circuit member, wherein the connecting member is a cured product of the adhesive composition of the present invention. Here, it is preferable that one of the first circuit board and the second circuit board is a flexible board.

  In the connection body according to the present invention, the connection member that electrically connects the first circuit member and the second circuit member is formed of a cured product of the adhesive composition of the present invention. The adhesive strength between the member and the cured product of the adhesive composition is sufficiently exhibited.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive strength between an adherend and an adhesive is fully exhibited even under conditions of lower temperature (for example, 140 [deg.] C. or less) as compared with the related art, and sufficiently high connection reliability is obtained. Adhesive composition can be provided. Furthermore, according to such an adhesive composition, even when the high temperature and high humidity treatment is performed after bonding to the adherend, a decrease in bonding strength and connection reliability is sufficiently suppressed, and further, the pot life is excellent.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic cross section which shows one Embodiment of the film adhesive which consists of an adhesive composition which concerns on this embodiment. It is a schematic cross section showing one embodiment of a connection object provided with a connection member which consists of a hardened material of an adhesive constituent concerning this embodiment. It is a flowchart showing one embodiment which manufactures a connection object with an adhesive constituent concerning this embodiment by a schematic sectional view.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. However, the present invention is not limited to the following embodiments. In the drawings, the same or corresponding parts have the same reference characters allotted, and overlapping description will be appropriately omitted. In this specification, (meth) acrylic acid means acrylic acid or methacrylic acid corresponding thereto. The same applies to other similar expressions such as (meth) acrylate.

  The adhesive composition according to the present embodiment contains (a) a thermoplastic resin, (b) a radically polymerizable compound, and (c) a radical polymerization initiator.

  As the thermoplastic resin (a), for example, one or more kinds selected from polyimide resin, polyamide resin, phenoxy resin, poly (meth) acrylic resin, polyester resin, polyurethane resin, polyester urethane resin and polyvinyl butyral resin Resins. Among them, it is preferable to include (a) a thermoplastic resin such as a polyimide resin, a polyamide resin, a phenoxy resin, a poly (meth) acrylic resin, a polyurethane resin, a polyester urethane resin, or a polyvinyl butyral resin.

  The lower limit of the weight average molecular weight of the thermoplastic resin may be 5,000 or more, 10,000 or more, or 25,000 or more. When the weight average molecular weight of the thermoplastic resin is 5,000 or more, the adhesive strength of the adhesive composition tends to be improved. On the other hand, the upper limit of the weight average molecular weight of the thermoplastic resin may be 400,000 or less, 200,000 or less, or 150,000 or less. When the weight average molecular weight of the thermoplastic resin is 400,000 or less, good compatibility with other components tends to be easily obtained, and fluidity of the adhesive tends to be easily obtained. In light of the above, the weight average molecular weight of the thermoplastic resin is preferably 5,000 to 400,000, more preferably 5,000 to 200,000, further preferably 10,000 to 150,000, and particularly preferably 25,000 to 150,000.

  As the thermoplastic resin, a rubber component can be used for the purpose of relaxing stress and improving adhesiveness.

  The content of the thermoplastic resin is preferably 20 to 80 parts by mass, more preferably 30 to 70 parts by mass, and preferably 35 to 70 parts by mass, based on 100 parts by mass of the total of the components (a) and (b). More preferably, the amount is 65 parts by mass. When the content of the thermoplastic resin is 20 parts by mass or more, the adhesive strength tends to be improved, and the film formability of the adhesive composition tends to be improved. Tend to be easily obtained.

  The adhesive composition according to the present embodiment includes, as the radical polymerizable compound (b), a radical polymerizable compound having an isocyanate group or a radical polymerizable compound having a structure in which an isocyanate group is generated by heating.

  The radically polymerizable compound preferably contains at least one compound having a structure in which an isocyanate group or an isocyanate group is generated by heating, and a radically polymerizable unsaturated group. The radically polymerizable unsaturated group is preferably a (meth) acryloyl group, more preferably a (meth) acryloyloxy group.

  As a method for producing a compound having an isocyanate group and a (meth) acryloyloxy group, as described in JP-A-2006-232797, a salt of an ester of (meth) acrylic acid and an amino alcohol with phosgene is reacted. And a method of reacting isopropenyl oxazoline with phosgene, a method of dehydrochlorinating a 3-chloropropionate derivative having an isocyanate group, and the like.

  The molecular weight of the compound having an isocyanate group and a (meth) acryloyloxy group is preferably 150 or more and less than 1,000. When the molecular weight is 150 or more, the compound tends to be less likely to volatilize in the production process of the adhesive composition. If the molecular weight is less than 1,000, sufficient fluidity tends to be easily obtained during heating.

  In the compound having an isocyanate group and a (meth) acryloyloxy group, the number of the isocyanate group and the (meth) acryloyloxy group in the molecule is not particularly limited, but it is practically independently about 1 to 5 each. It is.

  Examples of the compound having an isocyanate group and a (meth) acryloyloxy group include 2- (meth) acryloyloxyethyl isocyanate, 2- (meth) acryloyloxymethyl isocyanate, 2- (meth) acryloyloxypropyl isocyanate, 1- (bisacryloyloxymethyl) ethyl isocyanate and the like.

  The adhesive composition according to the present embodiment may contain, as the radical polymerizable compound (b), a radical polymerizable compound having a structure in which an isocyanate group is generated by heating. By using such a compound, the pot life of the adhesive can be further improved.

  The structure in which an isocyanate group is generated by heating can be synthesized by chemically blocking the isocyanate group with a blocking agent or the like. Blocking agents include, for example, dimethyl pyrazole, dimethyl malonate, diethyl malonate, methyl ethyl ketone oxime and caprolactam. Since the temperature at which the blocking agent dissociates can be controlled by the type of the blocking agent, one of these blocking agents can be used alone or in combination of two or more in accordance with the practical temperature.

  Examples of the compound having a structure in which an isocyanate group is generated by heating and a (meth) acryloyloxy group synthesized by the above method include, for example, a compound having an isocyanate group and a (meth) acryloyloxy group as described above. Compounds blocked with agents. Specific examples thereof include 2- (0- [1′-methylpropylideneamino] carboxyamino) ethyl (meth) acrylate.

  The total content of the radical polymerizable compound having an isocyanate group or the radical polymerizable compound having a structure in which an isocyanate group is generated by heating is 2 to 12 parts by mass based on 100 parts by mass of the components (a) and (b). It is preferably 3.5 parts by mass, more preferably 3.5 parts by mass, even more preferably 4 parts by mass to 9 parts by mass. When the content is 2 parts by mass or more, the adhesive strength to an adherend tends to be higher. When the content is 12 parts by mass or less, the pot life of the adhesive tends to be further improved, and the generation of bubbles after curing can be suppressed, so that better connection reliability can be obtained. .

  The adhesive composition according to the present embodiment includes, in addition to the radical polymerizable compound having an isocyanate group or the radical polymerizable compound having a structure in which an isocyanate group is generated by heating, (b) a radical polymerizable compound as the radical polymerizable compound. Any other compound having a non-functional functional group may be included. The other compound may be, for example, either a monomer or an oligomer of the compound described below, or may be a combination of both.

  As the above compound, one or more polyfunctional (meth) acrylate compounds having two or more (meth) acryloyloxy groups are preferable. Such (meth) acrylate compounds include, for example, epoxy (meth) acrylate, urethane (meth) acrylate, polyether (meth) acrylate, polyester (meth) acrylate, trimethylolpropane tri (meth) acrylate, and polyethylene glycol diacrylate. Polyalkylene glycol di (meth) acrylates such as (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, neopentyl glycol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate Acrylate, isocyanuric acid-modified bifunctional (meth) acrylate and isocyanuric acid-modified trifunctional (meth) acrylate are exemplified. Examples of the epoxy (meth) acrylate include an epoxy (meth) acrylate in which (meth) acrylic acid is added to two glycidyl groups of bisphenol full orange glycidyl ether and an ethylene glycol in two glycidyl groups of bisphenol full orange glycidyl ether. And / or a compound obtained by introducing a (meth) acryloyloxy group to a compound to which propylene glycol has been added. These compounds can be used alone or in combination of two or more.

  Further, the adhesive composition may contain a monofunctional (meth) acrylate compound as the radical polymerizable compound (b) for the purpose of adjusting fluidity or the like. Examples of the monofunctional (meth) acrylate compound include pentaerythritol (meth) acrylate, 2-cyanoethyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and 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-phenoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2- (meth) acryloyloxyethyl phosphate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (Meth) acrylate, glycidyl group-containing (meth) acrylate and (meth) acryloyl morpholine obtained by reacting one of glycidyl groups of an epoxy resin having a plurality of glycidyl groups with (meth) acrylic acid are exemplified. These compounds can be used alone or in combination of two or more.

  Further, the adhesive composition contains a compound having a radically polymerizable functional group such as an allyl group, a maleimide group, or a vinyl group as (b) a radically polymerizable compound for the purpose of improving a crosslinking ratio or the like. Is also good.

  The adhesive composition preferably contains a radical polymerizable compound having a phosphate group as the radical polymerizable compound (b) for the purpose of improving the adhesive strength. Examples of the radical polymerizable compound having a phosphate group include compounds represented by the following formulas (1), (2), and (3).

式（１）中、Ｒ^５は水素原子又はメチル基を示し、Ｒ^６は（メタ）アクリロイルオキシ基を示し、ｗ及びｘはそれぞれ独立に１〜８の整数を示す。なお、同一分子中の複数のＲ^５、Ｒ^６、ｗ及びｘは、それぞれ同一でも異なっていてもよい。

In the formula (1), R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents a (meth) acryloyloxy group, and w and x each independently represent an integer of 1 to 8. A plurality of R ⁵ , R ⁶ , w and x in the same molecule may be the same or different.

式（２）中、Ｒ^７は（メタ）アクリロイルオキシ基を示し、ｙ及びｚはそれぞれ独立に１〜８の整数を示す。同一分子中の複数のＲ^７、ｙ及びｚは、それぞれ同一でも異なっていてもよい。

In the formula (2), R ⁷ represents a (meth) acryloyloxy group, and y and z each independently represent an integer of 1 to 8. A plurality of R ⁷ , y and z in the same molecule may be the same or different.

式（３）中、Ｒ^８は水素原子又はメチル基を示し、Ｒ^９は（メタ）アクリロイルオキシ基を示し、ｂ及びｃはそれぞれ独立に１〜８の整数を示す。同一分子中の複数のＲ^８及びｂは同一でも異なっていてもよい。

In the formula (3), R ⁸ represents a hydrogen atom or a methyl group, R ⁹ represents a (meth) acryloyloxy group, and b and c each independently represent an integer of 1 to 8. A plurality of R ⁸ and b in the same molecule may be the same or different.

  Examples of the radical polymerizable compound having a phosphate group include acid phosphooxyethyl (meth) acrylate, acid phosphooxypropyl (meth) acrylate, acid phosphooxypolyoxyethylene glycol mono (meth) acrylate, and acid phosphooxypolyoxy. Propylene glycol mono (meth) acrylate, 2,2′-di (meth) acryloyloxydiethyl phosphate, EO (ethylene oxide) -modified di (meth) acrylate phosphate, phosphate-modified epoxy (meth) acrylate and vinyl phosphate No. These compounds can be used alone or in combination of two or more.

  The content of the radical polymerizable compound having a phosphate group is preferably from 0.1 to 15 parts by mass, and more preferably from 0.5 to 10 parts by mass, based on 100 parts by mass of the total of the components (a) and (b). It is more preferable that the amount be from 1 to 5 parts by mass. When the content of the radically polymerizable compound having a phosphate group is 0.1 parts by mass or more, high adhesive strength tends to be easily obtained, and when the content is 15 parts by mass or less, the adhesive composition after curing is used. The deterioration of the physical properties hardly occurs, and the effect of improving the reliability is improved.

  The total content of the (b) radically polymerizable compound contained in the adhesive composition is preferably 20 to 80 parts by mass with respect to 100 parts by mass of the total amount of the components (a) and (b). The amount is more preferably from 70 to 70 parts by mass, and still more preferably from 35 to 65 parts by mass. If the total content is 20 parts by mass or more, the heat resistance tends to be improved, and if it is 80 parts by mass or less, the effect of suppressing peeling after being left in a high-temperature and high-humidity environment tends to be large.

  (C) The radical polymerization initiator can be arbitrarily selected from compounds such as peroxides and azo compounds. From the viewpoints of stability, reactivity and compatibility, a peroxide having a one-minute half-life temperature of 90 to 175 ° C and a molecular weight of 180 to 1000 is preferable. "One minute half-life temperature" refers to the temperature at which the half-life of the peroxide is one minute. "Half-life" refers to the time it takes for the concentration of a compound to decrease to half its initial value at a given temperature.

  Examples of the radical polymerization initiator include 1,1,3,3-tetramethylbutylperoxy neodecanoate, di (4-t-butylcyclohexyl) peroxydicarbonate, and di (2-ethylhexyl) peroxydicarbonate. Carbonate, cumyl peroxy neodecanoate, 1,1,3,3-tetramethylbutyl peroxy neodecanoate, dilauroyl peroxide, 1-cyclohexyl-1-methylethyl peroxy neodecanoate, t- Hexyl peroxy neodecanoate, t-butyl peroxy neodecanoate, t-butyl peroxy pivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5 -Dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, t-hexylpa Oxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyneoheptanoate, t-amylperoxy-2-ethylhexanoate, di-t-butyl Peroxyhexahydroterephthalate, t-amylperoxy-3,5,5-trimethylhexanoate, 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate, 1,1,3,3-tetramethyl Butyl peroxy-2-ethylhexanoate, t-amyl peroxy neodecanoate, t-amyl peroxy-2-ethyl hexanoate, 3-methylbenzoyl peroxide, 4-methylbenzoyl peroxide, di ( 3-methylbenzoyl) peroxide, dibenzoyl peroxide, di (4-methyl Zoyl) peroxide, 2,2′-azobis-2,4-dimethylvaleronitrile, 1,1′-azobis (1-acetoxy-1-phenylethane), 2,2′-azobisisobutyronitrile, , 2'-Azobis (2-methylbutyronitrile), dimethyl-2,2'-azobisisobutyronitrile, 4,4'-azobis (4-cyanovaleric acid), 1,1'-azobis (1- Cyclohexanecarbonitrile), t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5 -Dimethyl-2,5-di (3-methylbenzoylperoxy) hexane, t-butylperoxy-2-ethylhexyl monocarbo , T-hexylperoxybenzoate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxybenzoate, dibutylperoxytrimethyl adipate, t-amylperoxy normal octoate, t -At least one compound selected from amyl peroxy isononanoate and t-amyl peroxy benzoate.

  The content of the radical polymerization initiator is preferably from 1 to 15 parts by mass, more preferably from 2.5 to 10 parts by mass, based on 100 parts by mass of the total of the components (a) and (b). Preferably, it is 3 to 8 parts by mass.

  The adhesive composition according to the present embodiment may contain a silane coupling agent. The silane coupling agent is preferably a compound represented by the following formula (4).

式（４）中、Ｒ^１、Ｒ^２及びＲ^３はそれぞれ独立に、水素原子、炭素数１〜５のアルキル基、炭素数１〜５のアルコキシ基、炭素数１〜５のアルコキシカルボニル基又はアリール基を示す。Ｒ^１、Ｒ^２及びＲ^３のうち少なくとも１つはアルコキシ基である。Ｒ^４は（メタ）アクリロイル基、（メタ）アクリロイルオキシ基、ビニル基、イソシアナート基、イミダゾール基、メルカプト基、アミノアルキル基で置換されていてもよいアミノ基、メチルアミノ基、ジメチルアミノ基、ベンジルアミノ基、フェニルアミノ基、シクロヘキシルアミノ基、モルホリノ基、ピペラジノ基、ウレイド基、グリシジル基又はグリシドキシ基を示す。ａは０〜１０の整数を示す。

In the formula (4), R ¹ , R ² and R ³ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkoxycarbonyl group having 1 to 5 carbon atoms or Indicates an aryl group. At least one of R ¹ , R ² and R ³ is an alkoxy group. R ⁴ represents a (meth) acryloyl group, a (meth) acryloyloxy group, a vinyl group, an isocyanate group, an imidazole group, a mercapto group, an amino group optionally substituted with an aminoalkyl group, a methylamino group, a dimethylamino group, A benzylamino group, a phenylamino group, a cyclohexylamino group, a morpholino group, a piperazino group, a ureido group, a glycidyl group or a glycidoxy group. a shows the integer of 0-10.

  Examples of the silane coupling agent of the formula (4) include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3- (meth) silane. Acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, N-2- (amino Ethyl) -3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane . These compounds can be used alone or in combination of two or more.

  The content of the silane coupling agent is preferably from 0.1 to 10 parts by mass, and more preferably from 0.25 to 5 parts by mass, based on 100 parts by mass of the components (a) and (b). Is more preferred. If the content of the silane coupling agent is 0.1 parts by mass or more, the effect of suppressing the separation of the interface between the circuit member and the circuit connection material, and the generation of bubbles tends to be greater, and the silane coupling agent When the content is 10 parts by mass or less, the pot life of the adhesive composition tends to be long.

  The adhesive composition according to the present embodiment may further contain (d) conductive particles. An adhesive composition containing conductive particles can be particularly suitably used as an anisotropic conductive adhesive.

  Examples of the conductive particles include metal particles such as Au, Ag, Pd, Ni, Cu, and solder, and carbon particles. In addition, the conductive particles are composite particles having core particles made of a non-conductive material such as glass, ceramic, and plastic, and a conductive layer such as metal, metal particles, or carbon that covers the core particles. You may. The metal particles may be copper particles and particles having a silver layer covering the copper particles. The core particles of the composite particles are preferably plastic particles.

  Since the composite particles having the plastic particles as core particles have deformability to be deformed by heating and pressurizing, when the circuit members are bonded to each other, the contact area between the circuit electrode of the circuit members and the conductive particles. Can be increased. For this reason, according to the adhesive composition containing these composite particles as conductive particles, a connection body that is more excellent in connection reliability can be obtained.

  The adhesive composition may contain insulating coated conductive particles having the conductive particles and an insulating layer or insulating particles covering at least a part of the surface thereof. The insulating layer can be provided by a method such as hybridization. The insulating layer or the insulating particles are formed from an insulating material such as a polymer resin. By using such insulating-coated conductive particles, a short circuit between adjacent conductive particles hardly occurs.

  The average particle size of the conductive particles is preferably 1 to 18 μm from the viewpoint of obtaining good dispersibility and conductivity.

  The content of the conductive particles is preferably from 0.1 to 30% by volume, more preferably from 0.1 to 10% by volume, and more preferably from 0.5 to 10% by volume, based on the total volume of the adhesive composition. More preferably, it is 7.5% by volume. When the content of the conductive particles is 0.1% by volume or more, the conductivity tends to be improved. When the content of the conductive particles is 30% by volume or less, there is a tendency that a short circuit between the circuit electrodes hardly occurs. The content (% by volume) of the conductive particles is determined based on the volume at 23 ° C. of each component constituting the adhesive composition before curing. The volume of each component can be determined by converting the mass into a volume using specific gravity. A suitable solvent (water, alcohol, etc.) that can wet the component without dissolving or swelling the component whose volume is to be measured is put in a measuring cylinder or the like, and the component to be measured is introduced there. The increased volume can also be determined as the volume of the component.

  The adhesive composition may contain insulating organic or inorganic fine particles in addition to the conductive particles. Examples of the inorganic fine particles include metal oxide fine particles such as silica fine particles, alumina fine particles, silica-alumina fine particles, titania fine particles, and zirconia fine particles, and nitride fine particles. Examples of the organic fine particles include silicone fine particles, methacrylate-butadiene-styrene fine particles, acryl-silicone fine particles, polyamide fine particles, and polyimide fine particles. These fine particles may have a uniform structure or may have a core-shell type structure.

The content of the organic fine particles and the inorganic fine particles is preferably 5 to 30 parts by mass, and preferably 7.5 to 20 parts by mass with respect to 100 parts by mass of the total of the components (a) and (b). More preferred. When the content of the organic fine particles and the inorganic fine particles is 5 parts by mass or more, it tends to be relatively easy to maintain the electrical connection between the opposing electrodes. There is a tendency for the fluidity of the product to improve.
The adhesive composition may contain various additives.

  When the adhesive composition according to this embodiment is liquid at normal temperature (25 ° C.), it can be used as a paste adhesive. When the adhesive composition is solid at room temperature, it may be used by heating, or may be used by adding a solvent to form a paste. Solvents used for pasting are not particularly limited as long as they have substantially no reactivity with the adhesive composition (including additives) and can sufficiently dissolve the adhesive composition. Not done.

  The adhesive composition according to the present embodiment can be formed into a film and used as a film adhesive. Film adhesive, for example, a solution obtained by adding a solvent or the like as necessary to the adhesive composition, a fluororesin film, polyethylene terephthalate film, coated on a release support such as release paper. And a method for removing a solvent and the like. The film adhesive is more convenient in terms of handling and the like.

  FIG. 1 is a schematic cross-sectional view showing one embodiment of a film adhesive made of the adhesive composition according to the present embodiment. The laminated film 100 shown in FIG. 1 includes a support 8 and a film adhesive 40 that is releasably laminated on the support 8. The film adhesive 40 is composed of the insulating adhesive layer 5 and the conductive particles 7 dispersed in the insulating adhesive layer 5. The insulating adhesive layer 5 is composed of components other than the conductive particles in the above-mentioned adhesive composition. According to this film adhesive, handling is easy, it can be easily installed on an adherend, and connection work can be easily performed. The film adhesive may have a multilayer structure composed of two or more layers. When the film adhesive contains conductive particles, the film adhesive can be suitably used as an anisotropic conductive film.

  According to the adhesive composition and the film adhesive according to the present embodiment, generally, the adherends can be bonded to each other by using both heat and pressure. The heating temperature is preferably 100 to 250 ° C. The pressure is not particularly limited as long as the pressure does not damage the adherend, but is generally preferably 0.1 to 10 MPa. These heating and pressurizing are preferably performed in a range of 0.5 to 120 seconds. According to the adhesive composition and the film adhesive according to the present embodiment, for example, the adherends are sufficiently adhered to each other even at a temperature of about 140 ° C. and a pressure of about 3 MPa with a short-time heating and pressurizing for 5 seconds. It is possible.

  The adhesive composition and the film adhesive according to the present embodiment can be used as adhesives for different types of adherends having different coefficients of thermal expansion. Specifically, the adhesive composition and the film adhesive according to the present embodiment include, in addition to the anisotropic conductive adhesive, a silver paste, a circuit connection material such as a silver film, a CSP elastomer, a CSP underfill material, It can be used as a semiconductor element adhesive material such as a LOC tape.

  Hereinafter, using the film adhesive according to the present embodiment as an anisotropic conductive film, a circuit board and circuit members having circuit electrodes formed on the main surface of the circuit board are connected as adherends, An example of manufacturing a connection body will be described.

  FIG. 2 is a schematic cross-sectional view showing one embodiment of a connection body provided with a connection member made of a cured product of the adhesive composition according to the present embodiment. The connection body 1 shown in FIG. 2 includes a first circuit member 20 and a second circuit member 30 that are arranged to face each other. Between the first circuit member 20 and the second circuit member 30, a connecting member 10 for bonding and connecting them is provided.

  The first circuit member 20 includes a first circuit board 21 and a first circuit electrode 22 formed on a main surface 21a of the first circuit board 21. An insulating layer may be formed on the main surface 21a of the first circuit board 21.

  The second circuit member 30 includes a second circuit board 31 and a second circuit electrode 32 formed on a main surface 31a of the second circuit board 31. An insulating layer may also be formed on the main surface 31a of the second circuit board 31.

  The first circuit member 20 and the second circuit member 30 are not particularly limited as long as they have circuit electrodes that require electrical connection. As the first circuit board 21 and the second circuit board 31, for example, a substrate made of an inorganic material such as a semiconductor, glass, or ceramic, a substrate made of an organic material such as polyimide or polycarbonate, or an inorganic material and an organic material such as glass / epoxy are used. Substrates. The first circuit board 21 may be a glass substrate, and the second circuit board 31 may be a flexible board (preferably, a resin film such as a polyimide film).

Specific examples of the circuit member to be connected include a glass or plastic substrate on which an electrode such as an indium tin oxide (ITO) film is formed, which is used for a liquid crystal display, a printed wiring board, a ceramic wiring board, and a flexible wiring board. And a semiconductor silicon chip. These are used in combination as needed. As described above, according to the adhesive composition according to the present embodiment, in addition to a member having a surface formed of an organic material such as a printed wiring board and a polyimide film, a metal such as copper and aluminum, ITO, and silicon nitride ( It can be used for bonding circuit members having a wide variety of surface states, such as members having a surface formed from an inorganic material such as SiN _x ) or silicon dioxide (SiO ₂ ).

  For example, when one circuit member is a solar cell having electrodes such as a finger electrode and a bus bar electrode, and the other circuit member is a tab wire, a connection body obtained by connecting these is a solar cell, It is a solar cell module including a tab wire and a connecting member (a cured product of an adhesive composition) for bonding these.

  The connection member 10 is made of a cured product of the adhesive composition according to the present embodiment. The connection member 10 includes an insulating layer 11 and conductive particles 7 dispersed in the insulating layer 11. The conductive particles 7 are arranged not only between the opposing first circuit electrode 22 and the second circuit electrode 32 but also between the main surfaces 21a and 31a. Since the first circuit electrode 22 and the second circuit electrode 32 are electrically connected via the conductive particles 7, the connection resistance between the first circuit electrode 22 and the second circuit electrode 32 is sufficient. To be reduced. Therefore, the flow of current between the first circuit electrode 22 and the second circuit electrode 32 can be made smooth, and the function of the circuit can be sufficiently exhibited. When the connection member does not contain conductive particles, the first circuit electrode 22 and the second circuit electrode 32 come into contact with each other to be electrically connected.

  Since the connecting member 10 is formed of the cured product of the adhesive composition according to the present embodiment, the bonding strength of the connecting member 10 to the first circuit member 20 and the second circuit member 30 is sufficiently high. Therefore, even after the reliability test (high-temperature high-humidity test), it is possible to sufficiently suppress the decrease in the adhesive strength and the increase in the connection resistance.

  The connector 1 includes, for example, a step of arranging a pair of circuit members having circuit electrodes and facing each other with a film-like adhesive made of an adhesive composition interposed therebetween, Bonding the pair of circuit members via a cured product of the adhesive composition (main connection step) by heating and curing the agent while pressing in the thickness direction of the film adhesive. Can be manufactured.

  FIG. 3 is a process diagram schematically showing a cross-sectional view of an embodiment for manufacturing a connection body using the adhesive composition according to the present embodiment. As shown in FIG. 3A, the film adhesive 40 is placed on the main surface of the first circuit member 20 on the first circuit electrode 22 side. When the film adhesive 40 is provided on the above-described support, the laminate of the film adhesive and the support is placed in a direction in which the film adhesive 40 is located on the first circuit member 20 side. Be placed on The film adhesive 40 is easy to handle because it is a film. For this reason, the film adhesive 40 can be easily interposed between the first circuit member 20 and the second circuit member 30, and the connection between the first circuit member 20 and the second circuit member 30 can be made. Work can be performed easily.

  The film adhesive 40 is the above-described adhesive composition (circuit connection material) formed in a film shape, and has the conductive particles 7 and the insulating adhesive layer 5. Even when the adhesive composition does not contain conductive particles, it can be used as a circuit connecting material for electrically connecting circuit electrodes by directly connecting the circuit electrodes. A circuit connecting material containing no conductive particles is sometimes called NCF (Non-Conductive-FILM) or NCP (Non-Conductive-Paste). When the adhesive composition has conductive particles, a circuit connecting material using the same may be referred to as ACF (Anisotropic Conductive FILM) or ACP (Anisotropic Conductive Paste).

  The thickness of the film adhesive 40 is preferably 10 to 50 μm. If the thickness of the film adhesive 40 is 10 μm or more, the space between the first circuit electrode 22 and the second circuit electrode 32 tends to be easily filled with the adhesive. When the thickness of the film adhesive is 50 μm or less, the adhesive composition between the first circuit electrode 22 and the second circuit electrode 32 can be sufficiently eliminated, and the first circuit electrode 22 and the second Conduction between the two circuit electrodes 32 can be easily ensured.

  By applying pressures A and B in the thickness direction of the film adhesive 40 as shown in FIG. 3A, the film adhesive 40 is temporarily connected to the first circuit member 20 (FIG. 3). (B)). At this time, pressure may be applied while heating. However, the heating temperature is set to a temperature at which the adhesive composition in the film adhesive 40 does not cure, that is, a temperature sufficiently lower than the temperature at which the radical polymerization initiator rapidly generates radicals.

  Subsequently, as shown in FIG. 3C, the second circuit member 30 is placed on the film adhesive 40 in a direction in which the second circuit electrode is located on the first circuit member 20 side. When the film adhesive 40 is provided on the support, the support is peeled off, and then the second circuit member 30 is placed on the film adhesive 40.

  Thereafter, the film adhesive 40 is heated while applying pressures A and B in the thickness direction. The heating temperature at this time is set to a temperature at which the radical polymerization initiator generates radicals sufficiently. As a result, radicals are generated from the radical polymerization initiator, and polymerization of the radically polymerizable compound is started. By this connection, the connection body shown in FIG. 2 is obtained. By heating the film adhesive 40, the insulating adhesive is cured in a state where the distance between the first circuit electrode 22 and the second circuit electrode 32 is sufficiently small, and the insulating layer 11 is formed. . As a result, the first circuit member 20 and the second circuit member 30 are firmly connected via the connection member 10 including the insulating layer 11.

  This connection is preferably performed under the conditions of a heating temperature of 100 to 250 ° C., a pressure of 0.1 to 10 MPa, and a pressing time of 0.5 to 120 seconds. These conditions are appropriately selected depending on the intended use, the adhesive composition, and the circuit member. According to the adhesive composition according to the present embodiment, a connector having sufficient reliability can be obtained even at a low temperature condition of 140 ° C. or lower. After the main connection, post-curing may be performed if necessary.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples.

<Synthesis of urethane acrylate>
In a 2-liter four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser, 4000 parts by mass of polycarbonate diol (manufactured by Aldrich, number average molecular weight Mn = 2000) and 2-hydroxy A reaction liquid was prepared by charging 238 parts by mass of ethyl acrylate, 0.49 parts by mass of hydroquinone monomethyl ether, and 4.9 parts by mass of a tin catalyst. To the reaction solution heated to 70 ° C., 666 parts by mass of isophorone diisocyanate (IPDI) was uniformly dropped over 3 hours to cause a reaction. After completion of the dropwise addition, the reaction was continued for 15 hours. When the NCO content was confirmed to be 0.2% by mass with an automatic potentiometric titrator (AT-510, manufactured by Kyoto Electronics Industry Co., Ltd.), the reaction was performed. Was completed to obtain a urethane acrylate. As a result of analysis by GPC (gel permeation chromatography), the weight average molecular weight of the urethane acrylate was 8,500 (standard polystyrene equivalent). The analysis by GPC was performed under the conditions shown in Table 1 below.

<Preparation of conductive particles>
A nickel layer having a thickness of 0.2 μm was formed on the surface of the polystyrene particles, and a gold layer having a thickness of 0.04 μm was formed outside the nickel layer. Thus, conductive particles having an average particle size of 4 μm were produced.

<Preparation of film adhesive>
The raw materials shown in Table 2 were mixed at the mass ratio shown in Table 2. The conductive particles were dispersed therein at a ratio of 1.5% by volume to obtain a coating liquid for forming a film adhesive. This coating liquid was applied to a 50 μm-thick polyethylene terephthalate (PET) film using a coating apparatus. The coating film was dried with hot air at 70 ° C. for 10 minutes to form an 18 μm thick film adhesive.

Each numerical value shown in Table 2 indicates parts by mass of the solid content. The specific substances of each raw material shown in Table 2 are as shown below.
Urethane acrylate: synthesized as described above,
Radical polymerizable compound A: methacryloyloxyethyl isocyanate (molecular weight 155.15, purity 99%),
-Radical polymerizable compound B: 2- (0- [1'-methylpropylideneamino] carboxyamino) ethyl methacrylate (molecular weight 240.00, purity 99%),
Radical polymerizable compound C: monofunctional acrylate compound (trade name: Alix CHA, manufactured by Toagosei Co., Ltd .: cyclohexyl acrylate),
Phenoxy resin: 40 mass% solution prepared by dissolving 40 g of PKHC (manufactured by Union Carbide, trade name: average molecular weight: 45,000) in 60 g of methyl ethyl ketone;
-Phosphate ester: 2-methacryloyloxyethyl acid phosphate (trade name: Light ester P-2M, manufactured by Kyoeisha Chemical Co., Ltd.),
-Silane coupling agent: 3-methacryloxypropyltrimethoxysilane (brand name: KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.),
-Peroxide: lauroyl peroxide (trade name: Parloyl L, manufactured by NOF Corporation: molecular weight 398.6),
-Inorganic fine particles: 10% by mass of a dispersion prepared by dispersing 10 g of silica particles (trade name: R104, manufactured by Nippon Aerosil Co., Ltd.) in a mixed solvent of 45 g of toluene and 45 g of ethyl acetate.

<Preparation of connection body>
A flexible circuit board (FPC) having 2200 copper circuits having a line width of 75 μm, a pitch of 150 μm, and a thickness of 18 μm using the film adhesive as a circuit connecting material, a glass substrate and a thickness of 0 mm formed on the glass substrate. An ITO substrate (thickness: 1.1 mm, surface resistance: 20Ω / □) having a thin layer of 0.2 μm indium oxide (ITO) was connected. The connection was performed by heating and pressing at 140 ° C. and 3 MPa for 5 seconds using a thermocompression bonding apparatus (heating method: constant heat type, manufactured by Toray Engineering Co., Ltd.). As a result, a connected body in which the FPC and the ITO substrate were connected to each other over a width of 1.5 mm with the cured product of the film adhesive was produced.

<Measurement of connection resistance and adhesive strength>
The resistance value (connection resistance) between adjacent circuits of the obtained connection was measured with a multimeter. The resistance value is represented by an average of 37 resistances between adjacent circuits. Further, the adhesive strength of the connection body was measured by a 90-degree peeling method according to JIS-Z0237. Tensilon UTM-4 (trade name, manufactured by Toyo Baldwin Co., Ltd., peel strength: 50 mm / min, 25 ° C.) was used as an adhesive strength measuring device. The connection resistance and the adhesive strength were measured for the connected body immediately after the connection and after being kept in a thermo-hygrostat at 85 ° C. and 85% RH for 250 hours. Table 3 shows the evaluation results.

<Evaluation of pot life>
Using the film-form adhesive treated at 40 ° C. for 3 days as a circuit connection material, a connection body was prepared in the same manner as described above, and the connection resistance and the adhesion strength were measured by the above-described methods. Table 3 shows the evaluation results.

  According to the film-like adhesive of each Example, good connection resistance (5 Ω or less) was obtained immediately after connection, after a high-temperature and high-humidity test, and after treatment at 40 ° C. for 3 days under low-temperature and short-time curing conditions. ) And adhesive strength (6 N / cm or more). In particular, in Example 5 using a film adhesive containing a radical polymerizable compound having a structure in which an isocyanate group is generated by heating, the adhesive strength after treatment at 40 ° C. for 3 days is more excellent, and the pot life is more improved. It was confirmed that it could be improved.

  On the other hand, in the case of the film adhesive of Comparative Example 1 containing no radical polymerizable compound having an isocyanate group or a radical polymerizable compound having a structure in which an isocyanate group is generated by heating as the radical polymerizable compound, immediately after connection, In both cases after the high-temperature and high-humidity test and after the treatment at 40 ° C. for 3 days, it was confirmed that a sufficient adhesive strength could not be obtained as compared with each of the examples.

  DESCRIPTION OF SYMBOLS 1 ... Connection body, 5 ... Insulating adhesive layer, 7 ... Conductivity particle, 8 ... Support body, 10 ... Connection member, 11 ... Insulation layer, 20 ... First circuit member, 21 ... First circuit board, 21a: Main surface, 22: First circuit electrode, 30: Second circuit member, 31: Second circuit board, 31a: Main surface, 32: Second circuit electrode, 40: Film adhesive, 100 ... Laminated film.

Claims (4)

(A) phenoxy resin,
(B) a radical polymerizable compound,
(C) a radical polymerization initiator, and (d) conductive particles,
An adhesive composition containing
The (b) radical polymerizable compound includes a radical polymerizable compound having an isocyanate group or a radical polymerizable compound having a structure in which an isocyanate group is generated by heating,
The radical polymerizable compound having an isocyanate group is 2- (meth) acryloyloxyethyl isocyanate, 2- (meth) acryloyloxymethyl isocyanate, 2- (meth) acryloyloxypropyl isocyanate and 1,1- (bisacryloyloxymethyl) ) Ri least 1 Tanedea selected from the group consisting of isocyanate,
The radical polymerizable compound having a structure in which an isocyanate group is generated by heating is a compound having an isocyanate group and a (meth) acryloyloxy group selected from dimethylpyrazole, dimethylmalonate, diethylmalonate, methylethylketone oxime, and caprolactam. Ru compounds der blocked with one blocking agent,
Adhesive composition.   The content of the radical polymerizable compound having an isocyanate group or the radical polymerizable compound having a structure in which an isocyanate group is generated by heating is based on 100 parts by mass of the total of (a) the phenoxy resin and (b) the radical polymerizable compound. The adhesive composition according to claim 1, which is 2 to 12 parts by mass. A first circuit member having a first circuit electrode formed on a main surface of a first circuit board,
A second circuit electrode is formed on the main surface of the second circuit board, and a second circuit member arranged so that the second circuit electrode and the first circuit electrode face each other,
A connection member that is provided between the first circuit member and the second circuit member and electrically connects the first circuit member and the second circuit member,
A connection body, wherein the connection member is a cured product of the adhesive composition according to claim 1.   The connection body according to claim 3, wherein one of the first circuit board and the second circuit board is a flexible board.

Images