JP2015166406A - Adhesive composition and connection body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition capable of sufficiently exhibiting an adhesive strength between an adherend and an adhesive even on a lower temperature (for instance, 140°C or lower) condition compared with a conventional one in a radical curing type adhesive.SOLUTION: An adhesive composition contains (a) a thermoplastic resin, (b) a radical polymerizable compound, and (c) a radical polymerization initiator. The (b) radical polymerizable compound contains a radical polymerizable compound having an isocyanate group or a radical polymerizable compound having such a structure that an isocyanate group is generated by heating.

Description

  The present invention relates to an adhesive composition and a connection body.

  In a semiconductor element or a liquid crystal display element, various adhesive compositions are conventionally used as a circuit connection material for the purpose of bonding various members in the element. The adhesive composition is required to have various properties such as adhesiveness, heat resistance, reliability in a high temperature and high humidity state, and the like.

The adherends to be bonded are various surfaces formed from various materials such as printed wiring boards, organic materials such as polyimide films, metals such as copper and aluminum, and metal compounds such as ITO, SiN and SiO _2. Have 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 an epoxy resin, a curing agent such as a phenol resin that reacts with the epoxy resin, and a thermal latent catalyst that promotes the reaction between the epoxy resin and the curing agent. Among these, the thermal latent catalyst is an important factor that determines the curing temperature and the curing rate. For this reason, various compounds are used as thermal latent catalysts from the viewpoint of storage stability at room temperature and curing rate during 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.

  Further, 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 terms of short-time curing because radicals which are reactive active species are rich in reactivity.

Japanese Patent Laid-Open No. 1-113480 International Publication No. 98/44067

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

  Furthermore, in order to reduce costs, it is necessary to improve throughput, and it is necessary to develop an adhesive composition that cures at a lower temperature and in a shorter time, in other words, an adhesive composition that is "low temperature fast cure". Has been.

  In order to achieve low temperature rapid curing of the adhesive composition, for example, in the above thermosetting resin composition, a thermal 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 storage stability at a level that is not problematic in practice. However, even when a radical curable adhesive is used, the radical polymerizable compound in the adhesive is almost reacted when cured at a lower temperature (for example, 140 ° C. or lower) compared to the conventional case. 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 is not sufficiently developed under low temperature conditions.

  The present invention has been made in view of the above-mentioned problems of the prior art, and in a radical curable adhesive, it adheres to an adherend even under conditions of a lower temperature (for example, 140 ° C. or lower) as compared with the conventional one. It aims at providing the adhesive composition which can fully express the adhesive strength with an agent.

  The present invention is an adhesive composition containing (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. An adhesive composition comprising a radically polymerizable compound having a structure or a radically polymerizable compound having a structure in which an isocyanate group is generated by heating is provided. According to such an adhesive composition, the adhesive strength between the adherend and the adhesive can be sufficiently expressed even under conditions of a lower temperature (for example, 140 ° C. or lower) than in the past.

  The content of the radically polymerizable compound having an isocyanate group or the radically 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 radically polymerizable compound. 2 to 12 parts by mass is preferable. By making content into this range, the effect mentioned above becomes larger.

  The adhesive composition of the present invention may further contain (d) conductive particles. By further containing conductive particles, the adhesive composition can be imparted with conductivity or anisotropic conductivity, so that the adhesive composition can be more suitably used as a circuit connection material. Moreover, 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 the main surface of the first circuit board, and a second circuit electrode formed on the main surface of the second circuit board. A second circuit member disposed so that the second circuit electrode and the first circuit electrode face each other; and the first circuit member provided between the first circuit member and the second circuit member. A connecting member that electrically connects 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, since the connection member that electrically connects the first circuit member and the second circuit member is constituted by the cured product of the adhesive composition of the present invention, each circuit Adhesive strength between the member and the cured product of the adhesive composition is sufficiently expressed.

  According to the present invention, the adhesive strength between the adherend and the adhesive is sufficiently expressed and the connection reliability is sufficiently high even at a lower temperature (eg, 140 ° C. or lower) than the conventional case. Can be provided. Further, according to such an adhesive composition, even when it is subjected to a high temperature and high humidity treatment after being bonded to an adherend, a decrease in adhesive strength and connection reliability is sufficiently suppressed, and furthermore, the pot life is excellent.

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 which shows one Embodiment of a connection body provided with the connection member which consists of hardened | cured material of the adhesive composition which concerns on this embodiment. It is process drawing which shows one Embodiment which manufactures a connection body with the adhesive composition which concerns on this embodiment with a schematic sectional drawing.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as the case may be. However, the present invention is not limited to the following embodiments. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and repeated description is omitted as appropriate. Moreover, in this specification, (meth) acrylic acid means acrylic acid or methacrylic acid corresponding to it. The same applies to other similar expressions such as (meth) acrylate.

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

  Examples of the thermoplastic resin (a) include one or more selected from polyimide resin, polyamide resin, phenoxy resin, poly (meth) acrylic resin, polyester resin, polyurethane resin, polyester urethane resin, and polyvinyl butyral resin. These resins are mentioned.

  The weight average molecular weight of the thermoplastic resin is preferably 5000 to 400000, more preferably 5000 to 200000, and still more preferably 10000 to 150,000. There exists a tendency for the adhesive strength of an adhesive composition to improve that the weight average molecular weight of a thermoplastic resin is 5000 or more. If the weight average molecular weight of the thermoplastic resin is 400000 or less, good compatibility with other components tends to be easily obtained, and the fluidity of the adhesive tends to be easily obtained.

  As the thermoplastic resin, a rubber component can also be used for the purpose of stress relaxation and adhesion improvement.

  The content of the thermoplastic resin is preferably 20 to 80 parts by mass, more preferably 30 to 70 parts by mass with respect to 100 parts by mass of the total amount of the components (a) and (b), 35 More preferably, it is -65 mass parts. If the content of the thermoplastic resin is 20 parts by mass or more, the adhesive strength tends to improve or the film forming property of the adhesive composition tends to improve. There is a tendency for fluidity to be easily obtained.

  The adhesive composition according to the present embodiment includes (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 as the radical polymerizable compound.

  The radical polymerizable compound preferably contains at least one compound having an isocyanate group or a structure in which an isocyanate group is generated by heating and a radical 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 (meth) acrylic acid, an amino alcohol ester and phosgene are reacted. A method of reacting isopropenyl oxazoline and phosgene, a method of dehydrochlorinating a 3-chloropropionic acid ester 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 1000. There exists a tendency for a compound to become difficult to volatilize in the manufacturing process of adhesive composition as the said molecular weight is 150 or more. If the molecular weight is less than 1000, sufficient fluidity tends to be obtained during heating.

  In the compound having an isocyanate group and a (meth) acryloyloxy group, there are no particular restrictions on the number of isocyanate groups and (meth) acryloyloxy groups in the molecule, but it is practically about 1 to 5 each independently. 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, Examples include 1- (bisacryloyloxymethyl) ethyl isocyanate.

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

  A 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. Examples of the blocking agent include dimethylpyrazole, dimethyl malonate, diethyl malonate, methyl ethyl ketone oxime and caprolactam. Since the temperature at which the blocking agent dissociates can be controlled depending on the type of the blocking agent, these blocking agents can be used alone or in combination of two or more in accordance with the practical temperature.

  As the compound synthesized by the above method and having a structure in which an isocyanate group is generated by heating and a (meth) acryloyloxy group, for example, the above-mentioned compound having an isocyanate group and a (meth) acryloyloxy group is blocked. And compounds blocked with an agent. Specific examples thereof include 2- (0- [1′-methylpropylideneamino] carboxyamino) ethyl (meth) acrylate.

  The total content of the radically polymerizable compound having an isocyanate group or the radically polymerizable compound having a structure in which an isocyanate group is generated by heating is 2 to 12 on the basis of 100 parts by mass of the total amount of the component (a) and the component (b). It is preferable that it is a mass part, and it is more preferable that it is 3.5-10 mass parts. There exists a tendency for adhesive strength with a to-be-adhered body to become higher that the said content is 2 mass parts or more. If the content is 12 parts by mass or less, the pot life of the adhesive tends to be further improved, generation of bubbles after curing can be suppressed, and better connection reliability can be obtained. .

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

  As said compound, the 1 type, or 2 or more types of polyfunctional (meth) acrylate compound which has a 2 or more (meth) acryloyloxy group is preferable. Examples of such (meth) acrylate compounds include epoxy (meth) acrylate, urethane (meth) acrylate, polyether (meth) acrylate, polyester (meth) acrylate, trimethylolpropane tri (meth) acrylate, and polyethylene glycol diester. Polyalkylene glycol di (meth) acrylate such as (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, neopentyl glycol di (meth) acrylate, dipentaerythritol hexa (meth) Examples include acrylate, isocyanuric acid-modified bifunctional (meth) acrylate, and isocyanuric acid-modified trifunctional (meth) acrylate. Examples of the epoxy (meth) acrylate include, for example, an epoxy (meth) acrylate obtained by adding (meth) acrylic acid to two glycidyl groups of bisphenol fluorenediglycidyl ether and ethylene glycol in two glycidyl groups of bisphenol fluorenediglycidyl ether. And / or the compound which introduce | transduced the (meth) acryloyloxy group to the compound which added propylene glycol is mentioned. These compounds can be used individually by 1 type or in combination of 2 or more types.

  Moreover, the adhesive composition may contain a monofunctional (meth) acrylate compound as the radically polymerizable compound (b) for the purpose of adjusting fluidity. Examples of monofunctional (meth) acrylate compounds 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) acryloylmorpholine obtained by reacting one of the glycidyl groups of an epoxy resin having a plurality of glycidyl groups with (meth) acrylic acid. These compounds can be used individually by 1 type or in combination of 2 or more types.

  Furthermore, the adhesive composition contains a compound having a radical polymerizable functional group such as an allyl group, a maleimide group, and a vinyl group as the (b) radical polymerizable compound for the purpose of improving the crosslinking rate. Also good.

  The adhesive composition preferably contains a radical polymerizable compound having a phosphate group as the (b) radical polymerizable compound for the purpose of improving the adhesive strength. Examples of the radically polymerizable compound having a phosphoric acid group include compounds represented by the following formula (1), (2) or (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 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 formula (2), R ⁷ represents a (meth) acryloyloxy group, and y and z each independently represents 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 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 phosphoric acid 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, phosphoric acid modified epoxy (meth) acrylate and vinyl phosphate Can be mentioned. These compounds can be used individually by 1 type or in combination of 2 or more types.

  The content of the radically polymerizable compound having a phosphate group is preferably 0.1 to 15 parts by mass with respect to 100 parts by mass of the total amount of the component (a) and the component (b), and 0.5 to 10 parts by mass. More preferably, it is part by mass. If the content of the radically polymerizable compound having a phosphoric acid group is 0.1 parts by mass or more, high adhesive strength tends to be obtained, and if it is 15 parts by mass or less, It is difficult to cause deterioration in physical properties, and the effect of improving reliability is good.

  The total content of the (b) radical 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 of the components (a) and (b). More preferably, it is -70 mass parts, and it is still more preferable that it is 35-65 mass parts. 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 leaving in a high temperature and high humidity environment tends to increase.

  (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 half-life temperature of 1 minute for 90 to 175 ° C. and a molecular weight of 180 to 1000 is preferable. “1 minute half-life temperature” refers to a temperature at which the half-life of the peroxide is 1 minute. “Half-life” refers to the time taken for the concentration of a compound to decrease to half of its initial value at a given temperature.

  Examples of the radical polymerization initiator include 1,1,3,3-tetramethylbutylperoxyneodecanoate, di (4-t-butylcyclohexyl) peroxydicarbonate, and di (2-ethylhexyl) peroxydi. Carbonate, cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, dilauroyl peroxide, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t- Hexyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy-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 Butylperoxy-2-ethylhexanoate, t-amylperoxyneodecanoate, t-amylperoxy-2-ethylhexanoate, 3-methylbenzoyl peroxide, 4-methylbenzoyl peroxide, di ( 3-methylbenzoyl) peroxide, dibenzoyl peroxide, di (4-methylbenzene) Zoyl) peroxide, 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-azobis (1-acetoxy-1-phenylethane), 2,2'-azobisisobutyronitrile, 2, , 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 Nate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxybenzoate, dibutylperoxytrimethyladipate, t-amylperoxynormal octoate, t -One or more compounds selected from amyl peroxy isononanoate and t-amyl peroxy benzoate.

  The content of the radical polymerization initiator is preferably 1 to 15 parts by mass and more preferably 2.5 to 10 parts by mass with respect to 100 parts by mass of the total amount of the components (a) and (b). preferable.

  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 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 An aryl group is shown. At least one of R ¹ , R ² and R ³ is an alkoxy group. R ⁴ is 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 represents an integer of 0 to 10.

  Examples of the silane coupling agent of the formula (4) include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3- (meth). 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 individually by 1 type or in combination of 2 or more types.

  It is preferable that content of a silane coupling agent is 0.1-10 mass parts with respect to 100 mass parts of total amounts of (a) component and (b) component, and is 0.25-5 mass parts. Is more preferable. 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 connecting material and the generation of bubbles tends to increase. 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 this embodiment may further contain (d) conductive particles. The 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. The conductive particles are composite particles having core particles made of a non-conductive material such as glass, ceramic, and plastic, and conductive layers such as metal, metal particles, and carbon that coat the core particles. May be. The metal particles may be copper particles and particles having a silver layer covering the copper particles. The core particle of the composite particle is preferably a plastic particle.

  The composite particles having the plastic particles as the core particles have a deformability that is deformed by heating and pressurization. Therefore, when the circuit members are bonded to each other, the contact area between the circuit electrodes of the circuit members and the conductive particles Can be increased. Therefore, according to the adhesive composition containing these composite particles as conductive particles, a connection body that is more excellent in terms of 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 part of the surface of the conductive particles. 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 coating conductive particles, short circuit between adjacent conductive particles is less likely to occur.

  The average particle diameter 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 0.1 to 30% by volume, more preferably 0.1 to 10% by volume, based on the total volume of the adhesive composition, More preferably, it is 7.5 volume%. If content of electroconductive particle is 0.1 volume% or more, there exists a tendency for electroconductivity to improve. If content of electroconductive particle is 30 volume% or less, there exists a tendency for it to become difficult to produce the short circuit between circuit electrodes. Content (volume%) of electroconductive particle is determined based on the volume in 23 degreeC of each component which comprises the adhesive composition before hardening. The volume of each component can be determined by converting mass to volume using specific gravity. Put an appropriate solvent (water, alcohol, etc.) that can wet the component well without dissolving or swelling the component whose volume is to be measured. The increased volume can be obtained 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 inorganic fine particles include metal fine particles such as silica fine particles, alumina fine particles, silica-alumina fine particles, titania fine particles, 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 a core-shell type structure.

The content of the organic fine particles and inorganic fine particles is preferably 5 to 30 parts by mass, and 7.5 to 20 parts by mass with respect to 100 parts by mass of the total amount of the component (a) and the component (b). More preferred. If the content of organic fine particles and 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, and if it is 30 parts by mass or less, the adhesive composition There is a tendency for the fluidity of things to improve.
The adhesive composition may contain various additives.

  The adhesive composition according to the present embodiment can be used as a paste-like adhesive when it is liquid at room temperature (25 ° C.). When the adhesive composition is solid at normal temperature, it may be used by heating, or it may be used by pasting it by adding a solvent. The solvent used for pasting is not particularly limited as long as it has substantially no reactivity with the adhesive composition (including additives) and can sufficiently dissolve the adhesive composition. Not.

  The adhesive composition according to this embodiment can be formed into a film and used as a film adhesive. For example, a film adhesive is obtained by applying a solution obtained by adding a solvent or the like to an adhesive composition as necessary on a peelable support such as a fluororesin film, a polyethylene terephthalate film, or a release paper. It can be obtained by a method of removing a solvent or the like. A film adhesive is more convenient in terms of handling and the like.

  FIG. 1 is a schematic cross-sectional view showing an embodiment of a film adhesive comprising the adhesive composition according to this embodiment. A laminated film 100 shown in FIG. 1 includes a support 8 and a film adhesive 40 laminated on the support 8 in a peelable manner. The film adhesive 40 is composed of an insulating adhesive layer 5 and conductive particles 7 dispersed in the insulating adhesive layer 5. The insulating adhesive layer 5 is comprised from components other than electroconductive particle among the above-mentioned adhesive compositions. According to this film adhesive, it is easy to handle, can be easily installed on the adherend, and can be easily connected. 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-like adhesive according to the present embodiment, the adherends can usually be bonded together using heating and pressurization together. The heating temperature is preferably 100 to 250 ° C. The pressure is not particularly limited as long as it does not damage the adherend, but it is generally preferably 0.1 to 10 MPa. These heating and pressurization are preferably performed in the range of 0.5 to 120 seconds. According to the adhesive composition and the film-like adhesive according to the present embodiment, for example, the adherends are sufficiently bonded to each other even when heated and pressed for a short period of 5 seconds under conditions of 140 ° C. and 3 MPa. It is possible.

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

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

  FIG. 2 is a schematic cross-sectional view showing an embodiment of a connection body including a connection member made of a cured product of the adhesive composition according to this 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. A connecting member 10 is provided between the first circuit member 20 and the second circuit member 30 to bond and connect them.

  The first circuit member 20 includes a first circuit board 21 and a first circuit electrode 22 formed on the main surface 21 a of the first circuit board 21. An insulating layer may be formed on the main surface 21 a 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 the main surface 31 a of the second circuit board 31. An insulating layer may also be formed on the main surface 31 a 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, an inorganic material such as glass / epoxy, and an organic material are used. A substrate containing. The first circuit board 21 may be a glass substrate, and the second circuit board 31 may be a flexible substrate (preferably a resin film such as a polyimide film).

Specific examples of circuit members to be connected include glass or plastic substrates, printed wiring boards, ceramic wiring boards, flexible wiring boards on which electrodes such as ITO (indium tin oxide) films are formed, which are used in liquid crystal displays. And a semiconductor silicon chip. These are used in combination as necessary. Thus, according to the adhesive composition according to the present embodiment, in addition to a member having a surface formed from an organic material such as a printed wiring board and a polyimide film, a metal such as copper or aluminum, ITO, silicon nitride ( It can be used for bonding circuit members having a wide variety of surface states, such as members having a surface formed of 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 busper electrode, and the other circuit member is a tab wire, the connection body obtained by connecting them is a solar cell, It is a solar cell module provided with a tab wire and a connecting member (cured product of the adhesive composition) for bonding them.

  The connection member 10 is made of a cured product of the adhesive composition according to this embodiment. The connecting member 10 contains an insulating layer 11 and conductive particles 7 dispersed in the insulating layer 11. The electroconductive particle 7 is arrange | positioned not only between the 1st circuit electrode 22 and the 2nd circuit electrode 32 which oppose but 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. Reduced to Therefore, the flow of current between the first circuit electrode 22 and the second circuit electrode 32 can be made smooth, and the functions of the circuit can be fully 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 connection member 10 is formed of the cured product of the adhesive composition according to this embodiment, the bonding strength of the connection member 10 to the first circuit member 20 and the second circuit member 30 is sufficiently high. Therefore, even after a reliability test (high temperature and high humidity test), it is possible to sufficiently suppress a decrease in adhesive strength and an increase in connection resistance.

  The connection body 1 includes, for example, a step of disposing a pair of circuit members having circuit electrodes disposed opposite to each other with a film adhesive made of an adhesive composition interposed therebetween, a pair of circuit members, and a film adhesive A step of bonding a 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 producing 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 a circuit member in such a direction that the film adhesive 40 is positioned on the first circuit member 20 side. It is put on. The film adhesive 40 is easy to handle because it is in the form of 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 is possible. Work can be done easily.

  The film adhesive 40 is the above-described adhesive composition (circuit connection material) formed in a film shape, and includes 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 connection material for electrical connection by directly connecting the circuit electrodes. The circuit connection material that does not contain 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 conductive particles 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. If 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 circuit electrode The 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). (See (b) of). At this time, you may pressurize, heating. However, the heating temperature is set to a temperature sufficiently lower than the temperature at which the adhesive composition in the film adhesive 40 is not cured, that is, 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 such a direction that the second circuit electrode is positioned on the first circuit member 20 side. In the case where the film adhesive 40 is provided on the support, the second circuit member 30 is placed on the film adhesive 40 after the support is peeled off.

  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 sufficiently generates radicals. As a result, radicals are generated from the radical polymerization initiator, and polymerization of the radical polymerizable compound is started. The connection shown in FIG. 2 is obtained by this connection. By heating the film adhesive 40, the insulating adhesive is cured to form the insulating layer 11 in a state where the distance between the first circuit electrode 22 and the second circuit electrode 32 is sufficiently small. . 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 pressurization 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 this embodiment, a connection body having sufficient reliability can be obtained even under a low temperature condition such as 140 ° C. or lower. After the connection, post-curing may be performed as 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>
Into 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 solution 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-based catalyst. To the reaction liquid heated to 70 ° C., 666 parts by mass of isophorone diisocyanate (IPDI) was uniformly dropped over 3 hours to be reacted. The reaction was continued for 15 hours after completion of the dropping, and the reaction was performed when it was confirmed that the NCO content became 0.2% by mass with an automatic potentiometric titrator (trade name AT-510, manufactured by Kyoto Electronics Industry Co., Ltd.). And urethane acrylate was obtained. As a result of analysis by GPC (gel permeation chromatography), the weight average molecular weight of urethane acrylate was 8500 (standard polystyrene conversion value). 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 further formed outside the nickel layer. Thus, conductive particles having an average particle diameter of 4 μm were produced.

<Production of film adhesive>
The raw materials shown in Table 2 were mixed at the mass ratio shown in Table 2. The said electroconductive particle was disperse | distributed in the ratio of 1.5 volume% there, and the coating liquid for forming a film adhesive was obtained. This coating solution was applied to a polyethylene terephthalate (PET) film having a thickness of 50 μm using a coating apparatus. The coating film was dried with hot air at 70 ° C. for 10 minutes to form a film adhesive having a thickness of 18 μm.

Each numerical value shown in Table 2 indicates a mass part of solid content. Moreover, the specific substance of each raw material described in Table 2 is 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% by mass solution prepared by dissolving 40 g of PKHC (manufactured by Union Carbide, trade name: average molecular weight 45000) 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 (trade name KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.),
Peroxide: Lauroyl peroxide (trade name Parroyl L, manufactured by NOF Corporation: molecular weight 398.6),
Inorganic fine particles: A 10% by mass 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.

<Production of connected body>
Using the film adhesive as a circuit connecting material, 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, a glass substrate and a thickness of 0 formed on the glass substrate An ITO substrate (thickness 1.1 mm, surface resistance 20Ω / □) having a thin layer of 2 μm indium oxide (ITO) was connected. The connection was made by heating and pressurizing 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 connection body in which the FPC and the ITO substrate were connected by a cured product of a film adhesive over a width of 1.5 mm was produced.

<Measurement of connection resistance and adhesive strength>
The resistance value (connection resistance) between adjacent circuits of the obtained connection body was measured with a multimeter. The resistance value is 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. Tensilon UTM-4 (manufactured by Toyo Baldwin Co., Ltd., trade name, 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 connection body immediately after the connection and after being kept in a constant temperature and humidity chamber at 85 ° C. and 85% RH for 250 hours. The evaluation results are shown in Table 3.

<Evaluation of pot life>
Using the film adhesive treated at 40 ° C. for 3 days as a circuit connecting material, a connected body was prepared by the same method as described above, and the connection resistance and adhesive strength were measured by the above method. The evaluation results are shown in Table 3.

  According to the film-like adhesives of each example, good connection resistance (5Ω or less) was obtained in all cases immediately after connection, after high-temperature and high-humidity test, and after treatment at 40 ° C. for 3 days, depending on 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 radically 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 enhanced. It was confirmed that it could be improved.

  On the other hand, in the case of the film-like adhesive of Comparative Example 1 that does not contain a radically polymerizable compound having an isocyanate group or a radically polymerizable compound having a structure in which an isocyanate group is generated by heating as a radically polymerizable compound, It was confirmed that sufficient adhesive strength was not obtained in each case after the high-temperature and high-humidity test and after the treatment at 40 ° C. for 3 days as compared with each example.

  DESCRIPTION OF SYMBOLS 1 ... Connection body, 5 ... Insulating adhesive layer, 7 ... Conductive particle, 8 ... Support body, 10 ... Connection member, 11 ... Insulating 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 (5)

(A) a thermoplastic resin,
(B) a radical polymerizable compound, and (c) a radical polymerization initiator,
An adhesive composition comprising:
The (b) radical polymerizable compound is an adhesive composition containing 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 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 100 parts by mass in total of the (a) thermoplastic resin and (b) radical polymerizable compound. On the other hand, the adhesive composition of Claim 1 which is 2-12 mass parts.   (D) The adhesive composition according to claim 1 or 2, further comprising conductive particles. A first circuit member having a first circuit electrode formed on the main surface of the first circuit board;
A second circuit member formed on the main surface of the second circuit board, wherein the second circuit electrode is disposed so that the second circuit electrode and the first circuit electrode face each other;
A connection member provided between the first circuit member and the second circuit member, and electrically connecting the first circuit member and the second circuit member;
The connection body whose said connection member is the hardened | cured material of the adhesive composition as described in any one of Claims 1-3.   The connection body according to claim 4, wherein one of the first circuit board and the second circuit board is a flexible board.

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