JP2016035044A - Conductive adhesive and electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive adhesive that solves conventional problems to ensure a desired adhesive strength at a low temperature, a low pressure and in a short time and to enable electrical connection between members.SOLUTION: The conductive adhesive according to the present invention comprises (A) a compound having an ethylenic unsaturated bond, (B) a peroxide, and (C) a conductive powder.SELECTED DRAWING: None

Description

  The present invention relates to a conductive adhesive, and more particularly to a conductive adhesive suitable for use in an electronic component that can electrically connect members at a low temperature, a low pressure, and in a short time.

  In the field of electronic equipment or circuit formation technology of electronic equipment, a method of obtaining electrical conductivity and connection strength by melting cream solder kneaded with conductive powder and flux has been used when electronic components are mounted on a substrate. However, in order to conductively connect the members using such cream solder, it is necessary to perform the treatment at a high temperature, so that damage to the mounted component due to heat has been a problem.

  On the other hand, a technique has been proposed in which conductive connection at a low temperature is possible using a low melting point solder and the adhesive strength of the low melting point solder is reinforced using an epoxy resin (Patent Document 1).

  However, this conventional technique has a problem that the conductive adhesive cannot be cured in a short time.

  On the other hand, processing at high temperature is disclosed as a technique for curing a low-melting-point conductive adhesive in a short time (Patent Document 2).

  However, this conventional technique has not yet achieved satisfactory adhesive strength.

  As described above, there is still no proposal for a technique that enables conductive connection with a conductive adhesive having excellent adhesive strength at low temperature, low pressure and in a short time.

JP2012-115881A JP2013-51353A

  An object of the present invention is to provide a conductive adhesive that can secure desired adhesive strength at low temperature, low pressure and in a short time and can electrically connect members to each other.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have completed the invention having the following contents.

  That is, the conductive adhesive of the present invention is characterized by containing (A) a compound having an ethylenically unsaturated bond, (B) peroxide, and (C) conductive powder.

  In such a conductive adhesive of the present invention, the (B) peroxide is preferably liquid. The liquid (B) liquid peroxide is preferably one or more compounds selected from peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxycarbonates, and peroxyesters. .

  In the conductive adhesive of the present invention, the (C) conductive powder is preferably a low melting point conductive powder.

  The conductive adhesive of the present invention preferably further contains a binder.

  The conductive adhesive of the present invention preferably contains no solvent.

  In the conductive adhesive of the present invention, the (A) compound having an ethylenically unsaturated bond is preferably a (meth) acryloyl group-containing monomer.

  The conductive adhesive of the present invention is preferably used for conductive bonding of electronic components, and the obtained electronic components are electrically connected to each other.

  ADVANTAGE OF THE INVENTION According to this invention, the desired adhesive strength can be ensured in low temperature, a low pressure, and for a short time, and the conductive adhesive which can electrically connect members can be provided.

  The conductive adhesive of the present invention includes (A) a compound having an ethylenically unsaturated bond, (B) peroxide, and (C) conductive powder.

  The conductive powder (C) used in the present invention is preferably a low-melting-point conductive powder, more preferably a low-melting-point lead-free solder, which contributes to electrical connection between members in an electronic component.

  The conductive adhesive of the present invention preferably contains no lead in components other than (C) the conductive powder, and contains (A) a compound having an ethylenically unsaturated bond and (B) peroxide, The electrical connection by the above-mentioned (C) conductive powder is reinforced in terms of adhesive strength. In particular, by using (B) peroxide, (A) the compound having an ethylenically unsaturated bond is cured at a low temperature in a short time. It was also found that the use of a liquid peroxide as the peroxide provided an effect specific to the present invention that was excellent in the storage stability of the paste.

  Below, the component which comprises the conductive adhesive of this invention is demonstrated.

[(A) Compound having ethylenically unsaturated bond]
The conductive adhesive of the present invention is a composition containing (A) a compound having an ethylenically unsaturated bond.

  (A) The compound having an ethylenically unsaturated bond can be used without particular limitation as long as it has an ethylenically unsaturated bond, and examples thereof include (meth) acryloyl group-containing compounds. In addition to the following monomers, those oligomers can also be used.

  Examples include compounds having an ethylenically unsaturated bond that undergoes radical polymerization. For example, monomers such as substituted or unsubstituted aliphatic acrylates, alicyclic acrylates, aromatic acrylates, and these ethylene oxide-modified acrylates, epoxy acrylates, urethanes Oligomers such as acrylates, polyester acrylates, polyether acrylates, polyol acrylates, alkyd acrylates, melamine acrylates, silicone acrylates, polybutadiene acrylates, and corresponding methacrylates can be used.

  More specifically, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, butoxymethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, hydroxyethyl (meth) Acrylate, hydroxypropyl (meth) acrylate, glycerol (meth) acrylate, 4- (meth) acryloxytricyclo [5.2.1.02.6] decane, isobornyl (meth) acrylate, isodecyl (meth) acrylate, phenoxy Ethyl (meth) acrylate, cyclohexyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, Monofunctional (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate, 4- (meth) acryloxyalkyl acid phosphate, γ- (meth) acryloxyalkyltrialkoxysilane; acryloylmorpholine, N-vinylpyrrolidone, N, Monofunctional monomers such as N-dimethylacrylamide, N-vinylcarbazole, styrene, vinyl acetate, acrylonitrile, trialkoxyvinylsilane; bisphenol-A-di (meth) acrylate, alkylene oxide modified bisphenol-A-di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, ethylene glycol di (meth) acrylate Triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) ) Acrylate, bis [4- (meth) acryloxymethyl] tricyclo [5.2.1.02.6] decane, bis [4- (meth) acryloxy-2-hydroxypropyloxyphenyl] propane, isophorone diisocyanate modified urethane di (Meth) acrylate, hexamethylene diisocyanate modified urethane di (meth) acrylate, trimethylhexamethylene diisocyanate modified urethane (meth) acrylate, trimethylhexa Tylene diisocyanate modified urethane (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, aliphatic epoxy modified (meth) acrylate, oligosiloxanyl di (meth) acrylate, etc. Polyfunctional (meth) acrylates; polyfunctional monomers such as triallyl isocyanurate, vinyl (meth) acrylate, allyl (meth) acrylate, etc., and compounds having these (meth) acrylate-based ethylenically unsaturated bonds Can be used alone or in admixture of two or more.

  In addition, the following compounds can also be used as the compound (A) having an ethylenically unsaturated bond of the present invention.

(1) Liquid polybutadiene urethane (meth) acrylate obtained by subjecting 2-hydroxyethyl (meth) acrylate to a urethane addition reaction with a hydroxyl group of liquid polybutadiene via 2,4-tolylene diisocyanate,
(2) Liquid polybutadiene acrylate obtained by esterifying 2-hydroxyacrylate with maleated polybutadiene to which maleic anhydride has been added,
(3) Liquid polybutadiene (meth) acrylate obtained by an epoxy esterification reaction between a carboxyl group of polybutadiene and glycidyl (meth) acrylate,
(4) Liquid polybutadiene (meth) acrylate obtained by esterification reaction of epoxidized polybutadiene obtained by allowing an epoxidizing agent to act on liquid polybutadiene and (meth) acrylic acid,
(5) Liquid polybutadiene (meth) acrylate obtained by dechlorination reaction of liquid polybutadiene having hydroxyl groups and (meth) acrylic acid chloride, and (6) Unsaturation of liquid polybutadiene having hydroxyl groups at both molecular ends. Liquid hydrogenated 1,2 polybutadiene (meth) acrylate obtained by modifying liquid hydrogenated 1,2 polybutadiene glycol hydrogenated with a heavy bond with urethane (meth) acrylate is preferably used.

  Examples of these commercially available products include NISSO PB TE-2000, NISSO PB TEA-1000, NISSO PB TE-3000, NISSO PB TEAI-1000 (all of which are manufactured by Nippon Soda Co., Ltd.), MM-1000-80, MAC- 1000-80 (all manufactured by Nippon Petrochemical Co., Ltd.), Polybeck ACR-LC (manufactured by Nippon Hydrazine Kogyo Co., Ltd.), HYCAR VT VTR 2000 × 164 (manufactured by Ube Industries), Quinbeam101 (manufactured by Nippon Zeon Co., Ltd.), Chemlink 5000 (SARTOMER BAC-15 (Osaka Organic Chemical Co., Ltd.), BAC-45 (Osaka Organic Chemical Co., Ltd.), UAT-2000 (Kyoeisha Chemical Co., Ltd.), Epolide PB-3600 (Daicel Chemical Co., Ltd.) RESIN, BR-45UAS (Light Chemi Cal Kogyo Co., Ltd.).

  Of these, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and polybutadienediol IPDI (isophorone isocyanate) modified urethane acrylate (BR-45UAS) are particularly preferable. -Hydroxy-3-phenoxypropyl (meth) acrylate is preferably used.

  These (A) compounds having an ethylenically unsaturated bond can be used alone or in combination.

  By using the (B) peroxide described later on such a compound having (A) an ethylenically unsaturated bond, the reaction is quickly started, rapid curing is possible, and the adhesive strength is improved.

  Here, the compounding quantity of this (A) compound which has an ethylenically unsaturated bond is 30-90 mass% with respect to the total mass of a conductive adhesive, Preferably it is 40-85 mass%, More preferably, it is 50-80. It is preferable that it is mass%.

  (A) By making the compounding quantity of the compound which has an ethylenically unsaturated bond into 30 mass% or more with respect to the total mass of a conductive adhesive, the fluidity | liquidity of a paste increases, handling becomes easy and adhesive strength. Is also considered good. In addition, by setting the blending amount of the compound having (A) the ethylenically unsaturated bond to 90% by mass or less with respect to the total mass of the conductive adhesive, the amount of solder in the paste is sufficiently secured, and the solder As a result, it is possible to ensure the metal connection that is originally necessary for the attachment.

[(B) Peroxide]
The conductive adhesive of the present invention contains (B) peroxide as a polymerization initiator for the compound (A) having an ethylenically unsaturated bond.

  The peroxide initiates a radical reaction of the compound having an ethylenically unsaturated bond. As a result, the adhesive force between members in the electronic component is improved.

  The (B) peroxide used in the present invention includes liquid and powdered peroxides, and specific examples thereof include the following materials.

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-hexylperoxide) Peroxyketals such as oxy) 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-butylperoxy) Peroxyketals such as oxy) cyclohexyl) propane,
hydroperoxides such as p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, and t-butyl hydroperoxide,
Di (2-t-butylperoxyisopropyl) benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-hexyl Dialkyl peroxides such as peroxide, di-t-butyl peroxide, and 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3;
Diisobutyl peroxide, di (3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, disuccinic acid peroxide, di- (3-methylbenzoyl) peroxide, benzoyl (3-methylbenzoyl) peroxide, Diacyl peroxides such as dibenzoyl peroxide and di- (4-methylbenzoyl) peroxide;
Di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate Peroxydicarbonate, etc.
Cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-butylper Oxyneoheptanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, 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-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, -Butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di (benzoylperoxy) ) Peroxyesters such as hexane, t-butylperoxyacetate, t-butylperoxy-3-methylbenzoate, and t-butylperoxybenzoate, and t-butylperoxyallyl monocarbonate, 3,3 ′, 4 , 4′-Tetra (t-butylperoxycarbonyl) benzophenone.

  Among such (B) peroxides, it is preferable to use a liquid one. By using liquid peroxide, an effect peculiar to the present invention that the storage stability of the paste is excellent can be obtained. Here, the liquid peroxide means a liquid peroxide at room temperature (25 ° C.) and atmospheric pressure.

  Usually, in a thermosetting composition, a powder curing agent is blended to give a function as a latent curing agent. However, in the present invention, by using a liquid peroxide, it is It was found that the storage stability of the adhesive was improved. As a result, according to the liquid peroxide, it is well dispersed in the conductive adhesive, and (A) works well on the compound having an ethylenically unsaturated bond to promote curing.

Examples of liquid peroxides include 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-hexylperoxy) cyclohexane, 1,1-di (t-butylperoxy) -2 -Peroxyketals such as 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-butylperoxy) Peroxyketals such as oxy) cyclohexyl) propane,
hydroperoxides such as p-menthane hydroperoxide, 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- Dialkyl peroxides such as 2,5-di (t-butylperoxy) hexyne-3;
Diacyl peroxides such as diisobutyl peroxide, di (3,5,5-trimethylhexanoyl) peroxide, di- (3-methylbenzoyl) peroxide, benzoyl (3-methylbenzoyl) peroxide, and dibenzoyl peroxide ,
Peroxydicarbonates such as di-n-propylperoxydicarbonate, diisopropylperoxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate,
Cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-butylper Oxyneoheptanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, 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-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, t-butyl peroxyacetate, t-butylperoxy-3-methylbenzoate, and t-butyl Mention may be made of peroxyesters such as peroxybenzoate, and t-butylperoxyallyl monocarbonate, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone.

  Among these, in the present invention, it is particularly preferable to use the following peroxides.

を用いることにより、極めて優れた接着強度が得られる。 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-di (t-hexylperoxy) cyclohexane, n-butyl-4,4-di- (t-butyl) Peroxy) peroxyketals such as 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-butylperoxy) 3-hexyne and other dialkyl peroxides,
Diacyl peroxide,
Peroxycarbonate, and 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate Ate, t-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,3,5-trimethylhexanoate, t-butylperoxylaurate, t-butylperoxy-2-ethylhexyl monocarbonate, t- Peroxyesters such as hexyl peroxybenzoate, t-butyl peroxy-3-methylbenzoate, and t-butyl peroxybenzoate.
Moreover, the outstanding adhesiveness is obtained by using peroxyester among said especially preferable peroxides. Among them, alkyl peroxyesters

By using, extremely excellent adhesive strength can be obtained.

  The (B) peroxide as described above preferably has a one-minute half-life temperature of 80 ° C. to 160 ° C., preferably 85 ° C. to 145 ° C., more preferably 90 ° C. to 135 ° C.

  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.

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

  The compounding quantity of such (B) peroxide is 0.1-10 mass% with respect to the compound which has (A) ethylenically unsaturated bond, Preferably it is 1-7 mass%, More preferably, it is 3-5 mass % Is appropriately selected.

  (B) 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 (A), sufficient sclerosis | hardenability can be ensured. Moreover, sufficient adhesiveness is securable by making the compounding quantity of a peroxide into 10 mass% or less with respect to the compound which has an (A) ethylenically unsaturated bond.

[(C) Conductive powder]
The conductive adhesive of the present invention includes (C) conductive powder.
Members are electrically connected by this conductive powder.
Examples of the conductive powder include Au, Ag, Ni, Cu, Pd, and metal powder of Sn, Bi, In, and Sb, carbon powder, and the like, which are materials such as low melting point solder described later. The conductive powder may be a composite powder in which a non-conductive powder such as glass, ceramic, or plastic as a core is coated with a metal layer, or a composite powder having the non-conductive powder and a metal powder or carbon powder. . When the conductive powder is the composite powder or the heat-meltable metal powder, the conductive powder is 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 powder, silver-coated copper powder or metal powder having a shape in which a large number of fine metal powders are connected in a chain shape can also be used.
In the conductive powder of the present invention, a low melting point conductive powder is preferable, and a lead-free conductive powder having a low melting point is more preferably used.

  Here, the low melting point conductive powder means a conductive powder having a melting point of 200 ° C. or lower, preferably 170 ° C. or lower, more preferably 150 ° C. or lower.

  Moreover, the electroconductive powder which does not contain lead means the electroconductive powder of 0.10 mass% or less of lead content prescribed | regulated by JISZ 3282 (solder-chemical component and shape).

  As such a conductive powder (C), 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 the conductive powder (C) is appropriately selected in the range of 15 to 65% by mass, preferably 35 to 65% by mass, and 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. When the Bi content is further 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.

  Such (C) conductive powder is preferably spherical particles, and the average particle diameter D50 is preferably 0.1 μm to 20 μm, preferably 3 μm to 17 μm, more preferably 7 μm to 15 μm. By setting the average particle diameter D50 of the conductive powder to 20 μm or less, sufficient conductive connection can be achieved even at a fine location. Moreover, aggregation of the conductive powder in the conductive adhesive can be suppressed by setting the average particle diameter D50 of the conductive powder to 0.1 μm or more.

  The blending amount of the conductive powder as described above (C) is appropriately selected in the range of 5 to 60% by mass, preferably 15 to 45% by mass, more preferably 25 to 35% by mass in the conductive adhesive. The

  (C) Sufficient conduction | electrical_connection connection can be ensured by the compounding quantity of electroconductive powder being 5 mass% or more in a conductive adhesive. Moreover, sufficient adhesiveness is securable by making the compounding quantity of (C) conductive powder into 60 mass% or less in a conductive adhesive.

[binder]
The conductive adhesive of the present invention preferably contains a binder. By adding this binder, the dispersion state of the conductive powder in the conductive adhesive is improved, and the adhesive strength is further improved.

  As such a binder, a known and commonly used thermoplastic resin can be used, and among them, a saturated polyester resin is preferably used.

  Specific examples of the saturated polyester resin include Byron 200, 220, 240, 245, 270, 280, 290, 296, 300, 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.

  The molecular weight (Mn) of such a binder is in the range of 1,000 to 100,000, preferably 3,000 to 50,000, more preferably 6,000 to 30,000. By setting it as this range, further favorable adhesive strength can be obtained without affecting the storage stability of the conductive adhesive.

[Other ingredients]
The conductive adhesive of the present invention as described above can be blended with additives such as known and commonly used thixotropic agents, antifoaming agents, and leveling agents as necessary.

In addition, an activator having a carboxyl group is generally used for a curable composition or a solder paste used for a copper electrode used in an electronic device or a circuit of the electronic device in order to remove a copper oxide film.

However, since an electrode used for a display member such as a liquid crystal panel or a touch panel is formed of a material other than copper such as a conductive paste such as silver or sputtering such as aluminum, such an electrode is an activator having the carboxyl group. The inventors have realized that they are more easily corroded.

  Therefore, it is preferable that the curable composition of the present invention does not contain an activator having a carboxyl group in the composition.

  The conductive adhesive of the present invention is used for electrical connection between members in an electronic component.

  For example, the conductive adhesive of the present invention is applied to an electrical connection location of a connection member in a printed wiring board or the like by pattern printing using a screen mesh or a metal mask, or a coating device 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) are electrically connected.

  In the present invention, excellent adhesive strength can be obtained by thermocompression bonding at a low temperature, a low pressure and in a short time, so that the electronic component is not damaged.

  Specifically, the thermocompression bonding temperature is 100 ° C. to 240 ° C., preferably 120 ° C. to 200 ° C., more preferably 140 to 160 ° C., and the thermocompression bonding pressure is 0.05 MPa to 3.0 MPa, preferably 0.1 MPa to The pressure is set to 2.0 MPa, more preferably 0.5 MPa to 1.5 MPa, and the thermocompression bonding time is 1 second to 60 seconds, preferably 1 second to 20 seconds, more preferably 1 second to 9 seconds. According to the treatment at a temperature of 100 ° C. or higher, the melting of the solder and the reaction of the compound having an ethylenically unsaturated bond proceed well, and by performing the treatment at a temperature of 240 ° C. or lower, the electronic component to be bonded, etc. Retains its original performance without being damaged by heating. Also, by setting the pressure to 0.05 MPa or more, sufficient solder joints are formed between the electronic components, and the conductivity is sufficient, and by setting the pressure to 3.0 MPa or less, an excessive load is applied to the electronic components. Damage due to application is avoided. In addition, by making the thermocompression bonding time short, damage to the electronic component due to heat can be avoided.

  Thus, if the conductive adhesive of this invention is used, desired adhesive strength can be ensured in low temperature, a low pressure, and a short time, and the members in an electronic component can be electrically connected.

  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 1-8 and Comparative Example 1)
I. Preparation of conductive adhesive Each component was blended and stirred at a blending ratio (mass ratio) shown in Table 1, and conductive adhesives of Examples 1 to 8 and Comparative Example 1 were prepared.

II. Evaluation of adhesive strength II-1. Preparation of test piece (1) Rigid substrate (copper substrate)
The conductive adhesives of Examples 1 to 8 and Comparative Example 1 prepared in I above were placed on a rigid substrate (base material: FR-4, pad width: 100 μm, pitch width: 0.2 mm, flash Au treatment). It 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, pad width: 100 μm, pitch width: 0.2 mm, flash Au treatment) was placed on the rigid substrate in a state where a conductive adhesive was applied. In this mounting, the position of the pad of the rigid substrate and the pad of the flexible substrate were aligned so that the length of the overlapping surface of both substrates was 4 mm. The bonded surfaces of the substrates placed in this manner were subjected to thermocompression bonding at 1.5 MPa and 150 ° C. for 6 seconds to prepare test pieces.
(2) Silver electrode substrate Substrate (silver electrode) obtained by patterning the conductive adhesive of Example 4 with soda lime glass (thickness 1.1 mm) with silver paste (ECM-100 AF6100 manufactured by Taiyo Ink Manufacturing Co., Ltd.) The substrate was coated with a scraper through a metal mask (mask thickness: 80 μm, opening: 15 mm × 1 mm) (pad width: 100 μm, pitch width: 0.2 mm). Next, a flexible substrate (width: 16 mm, base material: polyimide, pad width: 100 μm, pitch width: 0.2 mm, flash Au treatment) was placed on the glass substrate coated with the conductive adhesive. In this mounting, the position of the pad of the rigid substrate and the pad of the flexible substrate were aligned so that the length of the overlapping surface of both substrates was 4 mm. The bonded surfaces of the substrates placed in this manner were subjected to thermocompression bonding at 1.5 MPa and 150 ° C. for 6 seconds to prepare test pieces.
(3) ITO substrate The conductive adhesive of Example 4 was placed on an ITO-deposited glass substrate (ITO base) (PD200 manufactured by Asahi Glass Co., Ltd., ITO thickness 500 mm) with a metal mask (mask thickness: 80 μm, opening: 15 mm × 1 mm). Was applied by a scraper. Next, a flexible substrate (width: 16 mm, base material: polyimide, pad width: 100 μm, pitch width: 0.2 mm, flash Au treatment) was placed on the glass substrate coated with the conductive adhesive. In this mounting, the position of the pad of the rigid substrate and the pad of the flexible substrate were aligned so that the length of the overlapping surface of both substrates was 4 mm. The bonded surfaces of the substrates placed in this manner were subjected to thermocompression bonding at 1.5 MPa and 150 ° C. for 6 seconds to prepare test pieces.
(4) Aluminum substrate
The conductive adhesive of Example 4 was applied on an aluminum rigid substrate (base material: FR-4, aluminum thickness 25 μm) with 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, pad width: 100 μm, pitch width: 0.2 mm, flash Au treatment) was placed on the glass substrate coated with the conductive adhesive. In this mounting, the position of the pad of the rigid substrate and the pad of the flexible substrate were aligned so that the length of the overlapping surface of both substrates was 4 mm. The bonded surfaces of the substrates placed in this manner were subjected to thermocompression bonding at 1.5 MPa and 150 ° C. for 6 seconds to prepare test pieces.

II-2. Measurement of Adhesive Strength For the prepared test piece, the flexible substrate was peeled in the vertical direction according to JIS K 6854-1, and the adhesive strength was measured. The obtained evaluation results are also shown in Table 1.

III. Evaluation of conductivity Using the test piece obtained in II-1 above, the conduction between the pad portion of the rigid substrate and the pad portion of the flexible substrate was confirmed by a tester (manufactured by Hioki Electric Co., Ltd., Digital High Tester 3256). evaluated. The evaluation criteria are as follows. The obtained evaluation results are also shown in Table 1.

○: Continuity was confirmed.
X: Conductivity was not confirmed.

IV. Evaluation of storage stability (thickening rate) The viscosity of the conductive adhesive prepared in I above was measured with an E-type viscometer (Cone plate viscometer TVH-33 manufactured by Toki Sangyo Co., Ltd., measuring temperature 25 ° C.). This was taken as the initial viscosity. Thereafter, the conductive adhesive was stored in a thermostat at 30 ° C. for 60 hours, and the viscosity after 60 hours was measured in the same manner using the E-type viscometer.

The thickening rate was calculated by the following formula.
Thickening rate (%) = ((viscosity after 60 hours (dPa · s) / initial viscosity (dPa · s)) − 1) × 100
The obtained evaluation results are also shown in Table 1. In addition, about the electroconductive adhesive which became gelled and became unable to measure viscosity, it described as "gelation" in Table 1.

  The detail of each component described in Table 1 is as follows.

Compound having ethylenically unsaturated bond (A-1): 2-hydroxy-3-phenoxypropyl acrylate (Aronix manufactured by Toagosei Co., Ltd.)
M-5700, molecular weight: 222, Tg: 17 ° C., viscosity: 1.65 dPa · s / 25 ° C.)
Compound (A-2) having an ethylenically unsaturated bond: Polybutadiene urethane acrylate (BR-45UAS manufactured by Light Chemical Industries, Ltd., molecular weight: Mw 3000, viscosity: 375 dPa · s / 25 ° C.)
Binder: Polyester resin (byron 500 manufactured by Toyobo Co., Ltd., molecular weight: Mn 23000, Tg: 4 ° C.)
Epoxy resin: bisphenol A type epoxy resin (828, manufactured by Mitsubishi Chemical Corporation, molecular weight: 370, viscosity: 138 dPa · s / 25 ° C.)
Curing agent: 2-ethyl-4-methylimidazole (2E4MZ, Shikoku Kasei Kogyo Co., Ltd., melting point: 40 ° C.) Peroxide (B-1): t-hexylperoxyisopropyl monocarbonate (property: liquid, 1 minute half-life temperature) : 155.0 ° C, 10 hour half-life temperature: 95.0 ° C)
Peroxide (B-2): 1,1-di (t-hexylperoxy) cyclohexane (Perhexa HC manufactured by NOF Corporation, property: liquid, 1 minute half-life temperature: 149.2 ° C., 10 hour half-life temperature : 87.1 ° C)
Peroxide (B-3): t-Butylperoxy-2-ethylhexanoate (NOF Corporation Perbutyl O, property: liquid, 1 minute half-life temperature: 134 ° C., 10 hour half-life temperature: 72.1 ℃)
Peroxide (B-4): 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (Perocta O manufactured by NOF Corporation, property: liquid, half-life temperature for 12 minutes: 124.3 ℃, 10 hours half-life temperature: 65.3 ℃)
Peroxide (B-5): t-hexylperoxy-2-ethylhexanoate (Perhexyl O manufactured by NOF Corporation, property: liquid, 1 minute half-life temperature: 90.1 ° C., 10 hour half-life temperature: 69.9 ° C)
Peroxide (B-6): Dibenzoyl peroxide (Nippa Nipper BW, properties: powder, 1 minute half-life temperature: 130 ° C., 10-hour half-life temperature: 73.6 ° C.)
Peroxide (B-7): Di (4-t-butylcyclohexyl) peroxydicarbonate (Perroyl TCP manufactured by NOF Corporation, properties: powder, 1 minute half-life temperature: 92.1 ° C., 10 hour half-life (Temperature: 40.8 ° C)
Conductive powder: spherical particles of 42Sn-58Bi composition (average particle diameter (D50): 13.12 μm)

  As is clear from the results shown in Table 1, it was confirmed that low temperature, low pressure, and short-time conductive bonding was possible by using a compound having an ethylenically unsaturated bond and peroxide.

  It was also confirmed that the use of liquid peroxide reduces the viscosity increase rate and improves the storage stability.

Claims (5)

(A) a compound having an ethylenically unsaturated bond;
(B) peroxide,
(C) Conductive powder Conductive adhesive comprising conductive powder.   The conductive adhesive according to claim 1, wherein the (B) peroxide is liquid.   The conductive adhesive according to claim 1, wherein the conductive powder (C) is a low melting point conductive powder.   The conductive adhesive according to claim 1, wherein the conductive adhesive is used for conductive bonding of electronic parts.   The electronic component by which members are electrically connected using the conductive adhesive of any one of Claims 1-4.