JP2017101131A - Conductive adhesive, cured product and electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive adhesive having excellent adhesion, a cured product of the conductive adhesive and an electronic component comprising a member electrically connected with the conductive adhesive.SOLUTION: The present invention provides a conductive adhesive comprising (A) a compound having an ethylenically unsaturated bond, (B) an organic binder, (C) a peroxide, (D) a conductive particle, and (E) a resin particle.SELECTED DRAWING: None

Description

  The present invention relates to a conductive adhesive, a cured product, and an electronic component.

  As the density of printed wiring boards is increasing due to the recent reduction in size and size of electronic devices, as a technology used for electrical connection of electronic components, for example, electrical connection between wiring boards and electronic elements, and electrical connection between wiring boards The development and improvement of conductive adhesives are underway (for example, Patent Documents 1 and 2). Such a conductive adhesive is applied between members to be electrically connected and thermocompression bonded, thereby enabling electrical connection in a lightweight and space-saving manner.

  Specifically, although the conductive adhesive itself is insulative, a conductive path is formed by sandwiching and pressing conductive particles contained in the conductive adhesive between the electrodes by thermocompression bonding. As a result, electrical connection between members becomes possible. On the other hand, since the conductive particles remain dispersed in a region where no pressure is applied without being sandwiched between the electrodes even after thermocompression bonding, insulation is maintained. As a result, a so-called anisotropic conductive connection structure is obtained.

JP 2012-216770 A JP2013-045650A

  The anisotropically conductive connection structure formed using the conductive adhesive as described above secures a path for electrically connecting members through conductive particles, but does not provide sufficient adhesion. There was a problem that there was a case.

  Therefore, an object of the present invention is to provide an electronic component including a conductive adhesive having excellent adhesion, a cured product of the conductive adhesive, and a member electrically connected using the conductive adhesive. .

  As a result of intensive research aimed at the realization of the above object, the present inventors have conducted conductive bonding from an electrically connected portion depending on the conditions of thermocompression bonding when electrically connecting members through a conductive adhesive. It has been found that sufficient adhesion cannot be obtained because the agent oozes out and the conductive adhesive decreases. About the exudation of this conductive adhesive, as a result of further earnest study, the inventors surprisingly suppressed the exudation of the conductive adhesive by including resin particles in the constituent components of the conductive adhesive, It has been found that the adhesion is improved, and the present invention has been completed.

  That is, the conductive adhesive of the present invention comprises (A) a compound having an ethylenically unsaturated bond, (B) an organic binder, (C) peroxide, (D) conductive particles, and (E) resin particles. It is characterized by including these.

  The cured product of the present invention is obtained by curing the conductive adhesive.

  The electronic component of the present invention includes a member electrically connected using the conductive adhesive.

  According to the present invention, it is possible to provide an electronic component including a conductive adhesive having excellent adhesion, a cured product of the conductive adhesive, and a member electrically connected using the conductive adhesive. Become.

  Hereinafter, the components contained in the conductive adhesive of the present invention will be described in detail.

[(A) Compound having ethylenically unsaturated bond]
The compound (A) having an ethylenically unsaturated bond constituting the conductive adhesive of the present invention can be used without particular limitation as long as it has an ethylenically unsaturated bond. (A) The compound having an ethylenically unsaturated bond is preferably a monomer or oligomer that can be used as a reactive diluent. Further, the compound (A) having an ethylenically unsaturated bond is preferably a monofunctional or polyfunctional (meth) acryloyl group-containing compound, and is a monofunctional or polyfunctional (meth) acryloyl group-containing monomer. Is preferred. Here, in the present specification, the (meth) acryloyl group is a term that collectively refers to an acryloyl group and a methacryloyl group, and the same applies to other similar expressions.

  Examples of the (meth) acryloyl group-containing compound include substituted or unsubstituted aliphatic acrylates, alicyclic acrylates, aromatic acrylates, heterocycle-containing acrylates, and ethylene oxide-modified acrylates, epoxy acrylates, and aromatic urethane acrylates. , Aliphatic urethane acrylate, polyester acrylate, polyether acrylate, polyol acrylate, alkyd acrylate, melamine acrylate, silicone acrylate, polybutadiene acrylate, and methacrylates corresponding to these can be used.

  More specifically, monofunctional (meth) acryloyl group-containing compounds include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) ) Acrylate, hydroxypropyl (meth) acrylate, butoxymethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, isodecyl (meth) acrylate, glycerol mono (meth) acrylate, etc. Alicyclic (meth) acrylates such as acrylate, cyclohexyl (meth) acrylate, 4- (meth) acryloxytricyclo [5.2.1.02,6] decane, isobornyl (meth) acrylate, phenoxyethyl (meth) Acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, aromatic (meth) acrylate such as 2-hydroxy-3-phenoxypropyl (meth) acrylate, modified (meth) acrylate such as aliphatic epoxy-modified (meth) acrylate, Tetrahydrofurfuryl (meth) acrylate, (meth) acryloyloxyethylphthalic acid, γ- (meth) acryloxyalkyltrialkoxysilane and the like can be used.

In addition, examples of the polyfunctional (meth) acryloyl group-containing compound include tripropylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, bisphenol-A-diglycidyl ether di (meth) acrylate, tetra Bifunctional (meth) acryloyl group-containing compounds such as ethylene glycol di (meth) acrylate, trifunctional (meth) acryloyl group-containing compounds such as trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra 4,5,6-functional (meth) acryloyl group-containing compounds such as (meth) acrylate, dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate can be used. .
The oligomeric (meth) acryloyl group-containing compounds include bisphenol A type epoxy (meth) acrylate, modified bisphenol A type epoxy (meth) acrylate, epoxidized soybean oil (meth) acrylate, aliphatic epoxy (meth) acrylate, Epoxy (meth) acrylates such as novolac epoxy (meth) acrylate and amine-modified bisphenol A type epoxy (meth) acrylate, and urethane (meth) acrylates such as aromatic urethane acrylate and aliphatic urethane acrylate can be used.
(A) A commercially available compound can be used as the compound having an ethylenically unsaturated bond.

  (A) The compound which has an ethylenically unsaturated bond can be used 1 type or in mixture of 2 or more types.

  (A) It is preferable to mix | blend the compound which has an ethylenically unsaturated bond in a conductive adhesive so that the ethylenically unsaturated bond equivalent in the organic component except a solvent may be 260 or more. Preferably it is 260-1000, More preferably, it is 300-700, More preferably, it is 350-700. By setting the ethylenically unsaturated bond equivalent to 260 or more, curing shrinkage that occurs during curing can be suppressed, and better adhesion can be obtained. Moreover, sufficient sclerosis | hardenability can be acquired because an ethylenically unsaturated bond equivalent shall be 1000 or less. Here, the ethylenically unsaturated bond equivalent is a mass per gram equivalent per number of ethylenically unsaturated bonds. When the ethylenically unsaturated group is a (meth) acryloyl group, it is generally called a (meth) acrylic equivalent. For example, when the ethylenically unsaturated group is a (meth) acryloyl group, it is defined as the mass of an organic component (excluding the solvent when a solvent is included) per (meth) acryloyl group. That is, the ethylenically unsaturated bond equivalent can be obtained by dividing the total mass of organic components (excluding the solvent when a solvent is included) by the number of ethylenically unsaturated bonds in the composition.

  By using a peroxide described later as a polymerization initiator for such a compound having an ethylenically unsaturated bond, the reaction is quickly started, rapid curing is possible, and adhesion is improved.

  (A) The compounding quantity of the compound which has an ethylenically unsaturated bond is 10-90 mass% with respect to the total mass of a conductive adhesive, Preferably it is 20-60 mass%. (A) By making the compounding quantity of the compound which has an ethylenically unsaturated bond into 10 mass% or more with respect to the total mass of a conductive adhesive, sufficient sclerosis | hardenability will be obtained and adhesiveness will also become better. . Moreover, (A) By making the compounding quantity of the compound which has an ethylenically unsaturated bond into 90 mass% or less with respect to the total mass of a conductive adhesive, cure shrinkage is suppressed and adhesiveness becomes more favorable.

  The conductive adhesive of the present invention may contain a reactive diluent other than the compound (A) having an ethylenically unsaturated bond, as long as the effects of the present invention are not impaired.

[(B) Organic binder]
The organic binder (B) constituting the conductive adhesive of the present invention is used to relieve stress generated during thermosetting and improve adhesion.

  The (B) organic binder in the present invention is a resin component that dissolves in the compound (A) having an ethylenically unsaturated bond, and known natural resins and synthetic resins can be used. Examples of the organic binder (B) include natural resins such as cellulose and rosin, polyethylene, polypropylene, polystyrene, polycarbonate, polyvinyl chloride, polyvinyl acetate, polyamide, acrylic resin, polyethylene terephthalate, fluororesin, silicone resin, A synthetic resin such as a polyester resin, an acetal resin, or a butyral resin can be used. Of these, acrylic resins, butyral resins, and saturated polyester resins are preferably used.

  Specific examples of the acrylic resin include Clarity LA2330 of Clarity series (manufactured by Kuraray Co., Ltd.).

  Specific examples of butyral resins include Sekisui Chemical S Lec Series (manufactured by Sekisui Chemical Co., Ltd.), S-LEC BL-1, BL-1H, BL-2, BL-2H, BL-5, BL-10, BL-10, BL-S, BL-L, etc. are mentioned.

  As specific examples of the saturated polyester resin, Byron 200, 220, 240, 245, 270, 280, 290, 296, 300, 337, 500, 530, 550, 560, 600 of Toyobo Byron series (manufactured by Toyobo Co., Ltd.) 630, 650, BX1001, GK110, 130, 140, 150, 180, 190, 250, 330, 590, 640, 680, 780, 810, 880, 890, and the like.

  (B) It is preferable to use a solid organic binder at room temperature (25 ° C.) and atmospheric pressure. By using a solid organic binder, it becomes easy to maintain the strength after curing of the conductive adhesive. The Tg (glass transition temperature) of the organic binder is -20 to 150 ° C, preferably 0 to 120 ° C, more preferably 10 to 70 ° C.

  (B) The molecular weight of the organic binder is 1,000 to 100,000, preferably 3,000 to 80,000, more preferably 5,000 to 60,000. If the molecular weight is 1,000 or more, the stress can be relaxed without bleeding out at the time of curing, and if it is 100,000 or less, it is easily compatible with a compound having an ethylenically unsaturated bond to obtain sufficient fluidity. be able to.

  (B) The compounding quantity of an organic binder is 1-90 mass% with respect to the total mass of a conductive adhesive, Preferably it is 5-60 mass%, More preferably, it is 10-40 mass%.

[(C) Peroxide)
According to the (C) peroxide constituting the conductive adhesive of the present invention, the compound having an ethylenically unsaturated bond can be cured at a low temperature in a short time, and as a result, the members of the electronic component Adhesion is improved.

  Examples of such (C) peroxide include liquid and powdered materials, and specific examples include the following.

  For example, ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, and acetylacetone peroxide, 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-di (t- Peroxyketals such as hexylperoxy) cyclohexane, 1,1-di (t-butylperoxy) -2-methylcyclohexane, and 1,1-di (t-butylperoxy) cyclohexane, 2,2-di ( t-butylperoxy) butane, n-butyl 4,4-di- (t-butylperoxy) valerate, 2,2-di (4,4-di- (t-butylperoxy) cyclohexyl) propane and the like Peroxyketal, p-menthane hydroperoxide, diisopropylbenzene hydride Hydroperoxides such as peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, and t-butyl hydroperoxide, di (2-t-butylperoxyisopropyl) benzene, di- Milperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-hexyl peroxide, di-t-butyl peroxide, and 2, Dialkyl peroxides such as 5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, diisobutyl peroxide, di (3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, dihaku Acid peroxide, di- (3-methylbenzoyl) par Diacyl peroxides such as oxide, benzoyl (3-methylbenzoyl) peroxide, dibenzoyl peroxide, and di- (4-methylbenzoyl) peroxide, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, Peroxydicarbonates such as di (4-t-butylcyclohexyl) peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, cumylperoxyneodecanoate, 1 , 1,3,3-tetramethylbutylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-butylperoxyneoheptanoate, t-hexyl Peroxypi Rate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) ) Hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-hexylperoxyisopropylmonocarbonate, t-butylperoxymaleic acid, t-butylper Oxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, 2 , 5-Dimethyl-2,5-di (benzoylperoxy) hexane peroxyesters such as t-butylperoxyacetate, t-butylperoxy-3-methylbenzoate, t-butylperoxybenzoate, and t-butylperoxyallyl monocarbonate, and 3,3 ′, 4,4 ′ -Tetra (t-butylperoxycarbonyl) benzophenone.

  Among such peroxides, it is preferable to use a liquid one. By using a liquid peroxide, a conductive adhesive excellent in storage stability can be obtained. Here, the liquid peroxide means a peroxide that is liquid at room temperature (25 ° C.) and atmospheric pressure.

  Usually, in a general thermosetting resin composition such as an epoxy resin, in order to provide a function as a latent curing agent, a powder curing agent is blended instead of a liquid. However, in the case of the thermosetting resin composition containing the compound having an ethylenically unsaturated bond, the storage stability of the composition is unexpectedly improved by using a liquid peroxide. As a result, according to the liquid peroxide, it is well dispersed in the conductive adhesive and works well on the compound having an ethylenically unsaturated bond to promote curing.

  Examples of the liquid peroxide include ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, and acetylacetone peroxide, 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1 Peroxyketals such as 1,1-di (t-hexylperoxy) cyclohexane, 1,1-di (t-butylperoxy) -2-methylcyclohexane, and 1,1-di (t-butylperoxy) cyclohexane 2,2-di (t-butylperoxy) butane, n-butyl 4,4-di- (t-butylperoxy) valerate, and 2,2-di (4,4-di- (t-butyl) Peroxy) cyclohexyl) peroxyketals such as propane, p-menthane hydroperoxide Hydroperoxides such as diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, and t-butyl hydroperoxide, 2,5-dimethyl-2,5- Di (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-hexyl peroxide, di-t-butyl peroxide, and 2,5-dimethyl-2,5-di (t-butylperoxide Dialkyl peroxides such as oxy) hexyne-3, diisobutyl peroxide, di (3,5,5-trimethylhexanoyl) peroxide, di- (3-methylbenzoyl) peroxide, and benzoyl (3-methylbenzoyl) peroxide Oxide, dibenzoyl peroxide, etc. Peroxydicarbonates such as acyl peroxide, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, cumylperoxy Neodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-butylperoxyneoheepta Noate, t-hexyl peroxypivalate, 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-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5-trimethylhexanoate, t- Butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, t-butyl peroxyacetate, t-butyl peroxy-3-methyl Mention may be made of peroxyesters such as benzoate, t-butyl peroxybenzoate, and t-butyl peroxyallyl monocarbonate, and 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone. .

（式中、ＲおよびＲ´はそれぞれ独立にアルキル基を表す。） Among these, preferable peroxides in the present invention include 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-di (t-hexylperoxy) cyclohexane, n- Peroxyketals such as butyl-4,4-di- (t-butylperoxy) valerate, hydroperoxides such as 1,1,3,3-tetramethylbutyl hydroperoxide, 2,5-dimethyl-2, 5-di (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-hexyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butyl) Peroxy) 3-hexyne and other dialkyl peroxides, diacyl peroxides, peroxycarbonates, and 1,1,3,3 Tetramethylbutylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-hexylperoxyisopropylmonocarbonate, t- Butyl peroxy-3,3,5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, t-butyl peroxy-3- Peroxyesters such as methyl benzoate and t-butyl peroxybenzoate. Further, among the particularly preferred peroxides described above, better adhesion can be obtained by using a peroxyester. Among them, extremely excellent adhesion can be obtained by using an alkyl peroxy ester having the following structure.

(In the formula, R and R ′ each independently represents an alkyl group.)

  It is preferable to use a peroxide having a half-life temperature of 80 to 160 ° C., preferably 85 to 145 ° C., more preferably 90 to 135 ° C. for one minute as described above. By setting the half-life temperature for 1 minute to 80 ° C. or more, a sufficient pot life can be secured for use at room temperature. Moreover, sufficient sclerosis | hardenability is securable by making 1 minute half life temperature into 160 degrees C or less.

  (C) Although peroxide is used independently, it can also be used in combination of multiple types.

  (C) The compounding quantity of a peroxide is 0.1-10 mass% with respect to the total mass of a conductive adhesive, Preferably it is 0.5-5 mass%, More preferably, it is 1.0-3.5 mass%. It is suitably selected within the range of (C) Sufficient curability is securable by making the compounding quantity of a peroxide into 0.1 mass% or more with respect to the compound which has an ethylenically unsaturated bond. (C) By making the compounding quantity of a peroxide into 10 mass% or less with respect to the compound which has an ethylenically unsaturated bond, more favorable adhesiveness can be ensured.

[(D) conductive particles]
The conductive adhesive of the present invention contains (D) conductive particles. Here, the conductive particles mean particles of a substance having a volume resistivity of 1 × 10 ⁶ Ω · cm or less.

  (D) The conductive particles are sandwiched between the electrodes, whereby the members are electrically connected.

  (D) The conductive particles constituting the conductive adhesive of the present invention are Sn, Bi, In, and Sb metal particles, such as Au, Ag, Ni, Cu, Pd, and low melting point solder described later, Examples thereof include carbon particles. The conductive particles may be composite particles obtained by coating non-conductive particles such as glass, ceramic, or plastic as a core with a metal layer, or composite particles having the non-conductive particles and metal particles or carbon particles. . When the conductive particles are the composite particles or the heat-meltable metal particles, the conductive particles are deformed by heating and pressurization, so that the contact area with the electrode is increased at the time of connection, and particularly high reliability is obtained. As the conductive particles, silver-coated copper particles or metal particles having a shape in which a large number of fine metal particles are connected in a chain shape can be used.

  As the (D) conductive particles, it is preferable to use heat-meltable conductive particles. In particular, it is preferable to use conductive particles that melt by thermocompression bonding at 170 ° C. or lower and 2 MPa or lower, and more preferably low melting point solder particles.

  Here, the low melting point solder particles mean solder particles having a melting point of 200 ° C. or lower, preferably 170 ° C. or lower, more preferably 150 ° C. or lower.

  The low melting point solder particles preferably include lead-free solder particles, and the lead-free solder particles are defined as JIS Z 3282 (solder-chemical component and shape) and have a lead content of 0.10. It means solder particles of less than mass%.

  As the solder particles not containing lead, a low melting point solder composed of one or more metals selected from tin, bismuth, indium, copper, silver, and antimony is preferably used. In particular, an alloy of tin (Sn) and bismuth (Bi) is preferably used from the viewpoint of balance of cost, handleability, and bonding strength.

  The content of Bi in such solder particles is appropriately selected in the range of 15 to 65% by mass, preferably 35 to 65% by mass, more preferably 55 to 60% by mass.

  By setting the Bi content to 15% by mass or more, the alloy starts to melt at about 160 ° C. Further, when the Bi content is increased, the melting start temperature decreases, and when it is 20% by mass or more, the melting start temperature becomes 139 ° C., and at 58% by mass, the eutectic composition is obtained. By setting the Bi content in the range of 15 to 65% by mass, the effect of lowering the melting point is sufficiently obtained, and as a result, sufficient conductive connection is obtained even at a low temperature.

  (D) The conductive particles are preferably spherical, and the average particle size D50 by laser diffraction particle size distribution measurement is 0.1 to 20 μm, preferably 3 to 17 μm, more preferably 7 to 15 μm. By setting the average particle diameter D50 of the conductive particles to 20 μm or less, sufficient conductive connection can be achieved even in a minute portion. Further, by setting the average particle diameter D50 of the conductive particles to 0.1 μm or more, aggregation of the conductive particles in the conductive adhesive can be suppressed. In the present invention, the term “spherical conductive particles” refers to those containing 90% or more of spherical powders having a major axis / minor axis ratio of 1 to 1.5 at a magnification at which the shape of the conductive particles can be confirmed.

  (D) It is preferable that the compounding quantity of electroconductive particle is 0.1-50 mass% with respect to the total mass of a conductive adhesive. More preferably, it is 5-40 mass%, More preferably, it is 10-35 mass%.

[(E) Resin particles]
The resin particles (E) constituting the conductive adhesive of the present invention are stained with the conductive adhesive from the electrical connection portion between members even under high temperature and high pressure conditions, for example, at 240 ° C. and 4.0 MPa. It is sufficient that it functions as a spacer without causing sticking out. Specifically, (A) particles of a resin component that does not dissolve in a compound having an ethylenically unsaturated bond are preferable, and known natural resins and synthetic resins are used. The particles can be used.

  In the present invention, spherical resin particles are preferably used as the resin particles (E). Here, the spherical resin particles refer to those containing 90% or more of particles having a ratio of major axis to minor axis of 1 to 1.5 at a magnification at which the shape of the resin particles can be confirmed. As the spherical resin particles, so-called resin beads may be used.

  (E) The average particle diameter of the resin particles is 1 to 40 μm, preferably more than 5 μm and 40 μm or less in order to function as a spacer.

  Examples of (E) resin particles include (meth) acrylate resins, styrene resins, styrene / (meth) acrylate resins, polyethylene resins, polypropylene resins, ABS resins, AS resins, polycarbonate resins, and phenol resins. Examples thereof include particles of organic resins such as resins, polyacetal resins, benzoguanamine resins, epoxy resins, polyester resins, polyamide resins, urethane resins, and polyimide resins. Such an organic resin may be either a crosslinked polymer or a non-crosslinked polymer. Further, the (E) resin particles may be core-shell type particles. Especially, it is preferable that (E) resin particle is a (meth) acrylate type resin particle, and it is more preferable that it is a polyalkyl (meth) acrylate type resin particle.

  Here, the cross-linked polymer means cross-linked fine particles obtained by cross-linking a compound having a functional group to resin particles made of a polymerizable monomer. Further, the non-crosslinked polymer refers to resin particles in which a polymerizable monomer has no crosslinking reaction with a compound having a functional group.

  Examples of commercial products of the polyalkyl (meth) acrylate resin particles include MX-1000, MX-1500H, MX-3000C and the like manufactured by Soken Chemical Co., Ltd.

  (E) The surface of the resin particles may be surface-treated with a dispersant, a coupling agent or the like.

  (E) The CV value (100 × (standard deviation of particle diameter [σ] / number average particle diameter [D])) [%] of the resin particles is preferably 0.1 to 50%, and preferably 1 to 40 % Is more preferable.

  (E) The true specific gravity of the resin particles is preferably 0.5 to 5, and more preferably 0.7 to 3.

  (E) It is preferable that the compounding quantity of the resin particle is 0.01-40 mass% with respect to the total mass of a conductive adhesive.

  The conductive adhesive of the present invention can be blended with additives such as known and commonly used thixotropy imparting agents, wetting and dispersing agents, and antifoaming agents as necessary.

  As the thixotropic agent, bentonite, wax, metal stearate, modified urea, silica and the like can be used. Among these, silica is preferable. The silica is preferably amorphous silica, more preferably amorphous silica having an average primary particle diameter of 50 nm or less, and particularly preferably hydrophobic amorphous silica having a hydrophobic surface.

  As the wetting and dispersing agent, aliphatic carboxylic acids, aliphatic carboxylates, higher alcohol sulfates, alkyl sulfonic acids, phosphate esters, polyethers, polyester carboxylic acids and their salts can be used. Of these, phosphate esters are preferred.

  As the antifoaming agent, silicone resin, modified silicone resin, organic polymer polymer, organic oligomer, and the like can be used. Among these, organic polymer polymers and organic oligomers are preferred, and vinyl ether polymers are more preferred.

  The conductive adhesive of the present invention preferably contains no solvent. Here, “not containing a solvent” means that the resin composition containing a resin component for an adhesive is substantially free of a solvent and is a resin composition containing a resin component for an adhesive at 150 ° C. for 30 minutes. It means that the decrease in mass due to heating is 3% by mass or less compared to the mass before heating.

  The conductive adhesive of the present invention can be used for electrical connection between members in an electronic component. For example, it can be used for electrical connection between a printed wiring board and an electronic element and electrical connection between printed wiring boards, and among them, it is preferably used for electrical connection between a rigid printed wiring board and a flexible printed wiring board. It can also be suitably used for electrical connection of wiring for driving a touch panel or a liquid crystal display. Moreover, it can use suitably also for the electrical connection in a smart phone, a tablet terminal, and a wearable terminal. Furthermore, since the high frequency characteristics are good, it can be suitably used for electrical connection in electronic devices that require high frequency characteristics.

  The method for applying the conductive adhesive according to the present invention is not particularly limited. For example, the conductive adhesive of the present invention is applied to the electrical connection portion of the connection member in a printed wiring board or the like using a screen mesh or a metal mask, Or it can apply | coat with coating apparatuses, such as a dispenser.

  After confirming that the conductive adhesive has been sufficiently supplied to the connection location, place the member to be connected (component) on the connection location of the connection member (substrate) and perform thermocompression bonding at a predetermined temperature and pressure. Harden. Thereby, a connection member (board | substrate) and a to-be-connected member (component) can be electrically connected.

  The thermocompression bonding temperature during thermocompression bonding is 100 to 240 ° C., preferably 120 to 200 ° C., more preferably 140 to 160 ° C., and the thermocompression bonding pressure is 0.05 to 4.0 MPa, preferably 0.1 to 3.0 MPa. More preferably, the pressure is 0.5 to 2.0 MPa, and the thermocompression bonding time is 1 to 60 seconds, preferably 1 to 30 seconds, and more preferably 1 to 15 seconds. When the treatment is performed at a temperature of 100 ° C. or higher, the thermal reaction proceeds satisfactorily. By performing the treatment at a temperature of 240 ° C. or less, the electronic components to be bonded are not damaged by heating, and the original performance is improved. Hold. Further, by setting the pressure to 0.05 MPa or more, sufficient bonding is formed between the electronic components, and the conductivity is sufficient. Further, by reducing the thermocompression bonding pressure, damage due to application of an excessive load to the electronic component can be avoided. In addition, by making the thermocompression bonding time short, damage to the electronic component due to heat can be avoided.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. In the following description, “part” and “%” are based on mass unless otherwise specified.

(Examples 1-5 and Comparative Example 1)
(Preparation of conductive adhesive)
The components were blended and stirred at the blending ratio (parts by mass) shown in Table 1, and conductive adhesives of Examples 1 to 5 and Comparative Example 1 were prepared.

(Preparation of test piece)
The conductive adhesives of Examples 1 to 5 and Comparative Example 1 prepared above were bonded to a rigid substrate (base material: FR-4, electrode width: 100 μm, electrode length: 6 mm, pitch width: 0.2 mm, The number of electrodes of 70, the straight electrode 1, and the flash Au treatment was applied by a scraper through a metal mask (mask thickness: 80 μm, opening: 15 mm × 1 mm). Next, a flexible substrate (width: 16 mm, base material: polyimide, electrode width: 100 μm, electrode length: 6 mm, pitch width: 0.2 mm, U-shape) on a rigid substrate in a state where a conductive adhesive is applied. The number of mold electrodes 70, the number of linear electrodes 1, flash Au treatment) were placed. In this mounting, the positions of the electrodes of the rigid substrate and the flexible substrate were aligned so that a daisy chain was formed, and the overlapping length of both electrodes was set to 3.5 mm. The bonded surfaces of the substrates placed in this manner were subjected to thermocompression bonding at 0.79 MPa (tool: width 3 mm, length 18 mm, load: 42.7 N), 150 ° C., 6 seconds, and 70 conductive connections. A daisy chain circuit test piece having a portion was prepared.

(Measurement of adhesion)
The adhesion strength of the test piece obtained by the above method is measured by peeling the flexible substrate in the vertical direction according to JIS K 6854-1 using a bond tester (4000 Plus manufactured by Nordson Advanced Technology). The numerical value of the displacement 3 mm was taken as the adhesion value.
(Conductivity check)
The continuity of the test piece obtained by the above method was confirmed by a tester (manufactured by Hioki Electric Co., Ltd., Digital High Tester 3256). The evaluation criteria are as follows.
○: Continuity was confirmed.
X: Conductivity was not confirmed.

＊１：（Ａ−１）フェノキシエチルアクリレート（共栄社化学社製「ライトアクリレートＰＯ−Ａ」）
＊２：（Ａ−２）脂肪族ウレタンアクリレート（ダイセル・オルネクス社製「ＥＢＥＣＲＹＬ２７０」、分子量１５００、Ｔｇ−２７℃、粘度３０ｄＰａ・ｓ／６０℃）
＊３：（Ｂ）ポリエステル樹脂（東洋紡社製「バイロン３３７」、分子量：Ｍｎ１００００、Ｔｇ：１４℃、性状：個体）
＊４：（Ｃ）１，１，３，３−テトラメチルブチルパーオキシ−２−エチルヘキサノエート（日油社製「パーオクタＯ」、１分間半減期温度：１２４．３℃、１０時間半減期温度：６５．３℃）
＊５：（Ｄ）４２Ｓｎ−５８Ｂｉ［４２Ｓｎ−５８Ｂｉ組成の球状粒子：平均粒径（Ｄ５０）、１３．１２μｍ）］
＊６：（Ｅ−１）架橋アクリル粒子（綜研化学社製「ＭＸ−１０００」、平均粒子径１０μｍ、真比重１．１９）
＊７：（Ｅ−２）架橋アクリル粒子（綜研化学社製「ＭＸ−１５００Ｈ」、平均粒子径１５μｍ、真比重１．１９）
＊８：（Ｅ−３）架橋アクリル粒子（綜研化学社製「ＭＸ−３０００Ｃ」、平均粒子径３０μｍ、真比重１．１９）
＊９：リン酸エステル（共栄社化学社製「ライトエステルＰ−２Ｍ」）
＊１０：ビニルエーテルポリマー（共栄社化学社製「フローレンＡＣ−３２６Ｆ」）
＊１１：シリカ微粒子（日本アエロジル社製、「エロジルＲ９７４」、比表面積１７０ｍ^２／ｇ）

* 1: (A-1) Phenoxyethyl acrylate (Kyoeisha Chemical Co., Ltd. “Light acrylate PO-A”)
* 2: (A-2) Aliphatic urethane acrylate ("EBECRYL 270" manufactured by Daicel Ornex Co., Ltd., molecular weight 1500, Tg-27 ° C, viscosity 30dPa · s / 60 ° C)
* 3: (B) polyester resin (“Byron 337” manufactured by Toyobo Co., Ltd., molecular weight: Mn10000, Tg: 14 ° C., property: solid)
* 4: (C) 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (“Perocta O” manufactured by NOF Corporation, 1 minute half-life temperature: 124.3 ° C., 10 hours half (Temperature: 65.3 ° C)
* 5: (D) 42Sn-58Bi [spherical particles having a composition of 42Sn-58Bi: average particle diameter (D50), 13.12 μm)]
* 6: (E-1) Cross-linked acrylic particles (“MX-1000” manufactured by Soken Chemical Co., Ltd., average particle diameter 10 μm, true specific gravity 1.19)
* 7: (E-2) cross-linked acrylic particles (“MX-1500H” manufactured by Soken Chemical Co., Ltd., average particle size 15 μm, true specific gravity 1.19)
* 8: (E-3) Crosslinked acrylic particles (“MX-3000C” manufactured by Soken Chemical Co., Ltd., average particle diameter 30 μm, true specific gravity 1.19)
* 9: Phosphate ester (Kyoeisha Chemical Co., Ltd. “Light Ester P-2M”)
* 10: Vinyl ether polymer (“Floren AC-326F” manufactured by Kyoeisha Chemical Co., Ltd.)
* 11: Silica fine particles (Nippon Aerosil Co., Ltd., “Erosil R974”, specific surface area 170 m ² / g)

  As shown in the said table | surface, it turns out that the conductive adhesive of this invention is excellent in adhesiveness.

Claims (3)

(A) a compound having an ethylenically unsaturated bond;
(B) an organic binder;
(C) peroxide,
(D) conductive particles;
(E) Resin particle | grains, Conductive adhesive agent characterized by the above-mentioned.   A cured product obtained by curing the conductive adhesive according to claim 1. An electronic component comprising a member electrically connected using the conductive adhesive according to claim 1.