JP2002235065A - Electrically conductive adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrically conductive adhesive composition capable of being cured with a small irradiation amount of an active energy beam and excellent in various physical properties. SOLUTION: This electrically conductive adhesive composition contains a compound having at least one oxetanyl group in its molecule and electrically conductive particles. The composition exhibits such characteristics as being cured with the small irradiation amount of the active energy beam while keeping good adhesion and electrical properties, so that it is useful for an electrically conductive adhesive and an electrically conductive adhesive film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive adhesive composition used for bonding electronic parts such as semiconductors and a conductive adhesive composition for a conductive adhesive film used for connecting between conductors. More specifically, the present invention relates to a conductive adhesive composition comprising a compound having at least one oxetanyl group in a molecule and conductive particles.

[0002]

2. Description of the Related Art A conductive adhesive (or a conductive paste) or a conductive adhesive film is composed of a binder and a conductive powder, etc., and is used for bonding, coating, and printing various electronic components, forming circuits, and connecting circuits. It is used for etc. As such a binder, a thermoplastic resin such as a urethane-based, polyester-based, or acrylic-based resin, or a thermosetting resin such as an epoxy-based or silicone-based resin is used. Particularly, an epoxy-based thermosetting resin has heat resistance and chemical resistance. It is often used from the viewpoint of adhesiveness, moisture resistance and the like.

As described above, epoxy resins are excellent in heat resistance, chemical resistance, adhesiveness, moisture resistance and the like, but have the disadvantage that they are inferior in low-temperature curability and rapid curability. If it takes a long time to cure the conductive resin, it will not only improve the productivity of electronic components and equipment using it, but also use it for bonding thermoplastic materials with low softening point such as polycarbonate. In this case, there is a problem that the substrate is thermally damaged in order to ensure reliable bonding. Therefore, resins used for conductive adhesives and conductive adhesive films are required to have not only excellent heat resistance, chemical resistance, adhesiveness, moisture resistance, etc., but also excellent low-temperature curability and rapid curability. Is done.

[0004] Anionic polymerization initiators such as tertiary amines and imidazoles, and cationic polymerization initiators such as aromatic diazonium salts and aromatic sulfonium salts are used for curing the epoxy resin. Agents are advantageous. And, in order to further improve the curability of such a cationic polymerization type epoxy resin, much research has been conducted on a cationic polymerization initiator. For example, JP-A-7-90237, JP-A-8-90237
JP-A-2455764 and JP-A-11-60899 disclose the use of various specific cationic polymerization initiators for low-temperature curing and rapid curing.

[0005] However, despite the devise of such initiators, the curability of conventional cationically polymerizable thermosetting resins such as epoxy resins is not yet satisfactory. Things. Therefore, a resin composition having excellent curability as a substitute for such a cationic polymerization type thermosetting resin, and also having various properties desired in a conductive adhesive or a conductive adhesive film, for example, good adhesiveness and electrical properties. There is a long-awaited need for product development in various fields including the electronic component industry.

It has been reported that an oxetane monomer having an oxetane ring which is a 4-membered cyclic ether as a polymerizable group has photocurability (Journal of Macromolecular Science, A29, No. 10, No. 91).
5, p. 1992; A30, 2 & 3, p. 173;
A30, 2 & 3, p. 189, 1993). Also,
U.S. Pat. No. 3,388,105 describes that an alicyclic alkane having an oxetanyl group and an epoxy group in the same molecule is cured by a heat addition reaction with a carboxyl group-containing compound. However, it is not known that this oxetane or alicyclic alkane exhibits extremely high activity (curability) for cation ring-opening polymerization, and it is difficult to cure by a small amount of active energy ray irradiation or a short heat treatment. It has not been known that it is suitable as a component of a conductive adhesive composition having excellent physical properties.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made in view of the above circumstances, and has a small amount of active energy ray irradiation or a conductive adhesive composition excellent in various physical properties which is cured by a short heat treatment. The task is to provide

[0008]

Means for Solving the Problems As a result of intensive studies on the solution of the above-mentioned problems, the present inventors have found that a specific conductive adhesive composition containing a compound having an oxetanyl group in a molecule and conductive particles has solved the problem. They have found that they can be solved, and have completed the present invention.

That is, the present invention provides the following [1] to [1]
[5] The present invention relates to a conductive adhesive composition, a conductive adhesive and a conductive adhesive film comprising the same, products manufactured using the same, and a method of curing the conductive adhesive composition. [1] A conductive adhesive composition comprising a compound (a) having at least one oxetanyl group in a molecule and conductive particles. [2] Compound (b) having at least one oxetanyl group and at least one epoxy group in the same molecule
And a conductive adhesive composition comprising the conductive particles. [3] A compound (a) having at least one oxetanyl group in the molecule, a compound (b) having at least one oxetanyl group and at least one epoxy group in the same molecule, and conductive particles. Conductive adhesive composition. [4] Compound (b) having at least one oxetanyl group and at least one epoxy group in the same molecule
Is an alicyclic alkane, the conductive adhesive composition according to [2] or [3]. [5] The conductive adhesive composition according to [4], wherein the alicyclic alkane is a compound represented by the general formula (1).

Embedded image Wherein R is a hydrogen atom or a methyl group, and m is 0 to 2
N is 2 when m is 0, and 1 otherwise.) [6] The compound represented by the general formula (1) is 7,8-epoxy-2-oxa-5-methyl-spiro [3.5] nonane and / or 6,7-epoxy-2-oxa-spiro [ 3.5] The conductive adhesive composition according to [5], which is nonane. [7] The conductive adhesive composition according to any one of [1] to [6], which contains a compound (c) that initiates cationic polymerization by irradiation with active energy rays and / or heating. [8] The conductivity according to [7], wherein the compound (c) that initiates cationic polymerization by irradiation with active energy rays and / or heating is at least one selected from a sulfonium salt, an iodonium salt, and a diazonium salt. Adhesive composition. [9] The conductive adhesive composition according to any one of [1] to [8], containing a compound (d) having one or more epoxy groups and not having an oxetanyl group. [10] The conductive adhesive composition according to any one of [1] to [9], containing the compound (e) having a radically polymerizable unsaturated group. [11] The conductive adhesive composition according to any one of [1] to [10], which contains a photoradical polymerization initiator (f). [12] A conductive adhesive comprising the conductive adhesive composition according to any one of [1] to [11]. [13] An electronic component and device manufactured using the conductive adhesive according to [12]. [14] A printed circuit manufactured using the conductive adhesive according to [12]. [15] A conductive adhesive film comprising the conductive adhesive composition according to any one of [1] to [11]. [16] An electronic component and device manufactured using the conductive adhesive film according to [15]. [17] A printed circuit manufactured using the conductive adhesive film according to [15]. [18] The method for curing a conductive adhesive composition according to any one of [1] to [11], wherein the conductive adhesive composition is cured by irradiation with active energy rays and / or heating. . [19] The method for curing the conductive adhesive composition according to [18], wherein the active energy rays are ultraviolet rays.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. Specific examples of the compound (a) having at least one oxetanyl group in a molecule used in the present invention include trimethylene oxide, 3,3-dimethyloxetane, 3,3-dichloromethyloxetane, and 3-ethyl-3. -Phenoxymethyloxetane, 3-ethyl-3-
Hydroxymethyl oxetane (Toagosei Co., Ltd .; trade name E
OXA), bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene (also called xylylenedioxetane; manufactured by Toagosei Co., Ltd .; trade name XDO), tri [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, Bis [(3-ethyl-3-oxetanylmethoxy) methylphenyl] ether, (3-ethyl-3-oxetanylmethoxy) oligodimethylsiloxane, a compound having a high-molecular-weight polyvalent oxetane ring, specifically an oxetane oligomer ( Toagosei Co., Ltd .; trade name Oligo-OX
T), 2-oxaspiro [3.5] nonane, 7-methyl-2-oxaspiro [3.5] nonane, spiro [adamantane-2,3′-oxetane], spiro [bicyclo [2.2.1] heptane -2,3'-oxetane], spiro [bicyclo [2.2.2] octane-2,3'-oxetane], spiro [7-oxabicyclo [2.2.
1] Heptane-2,3′-oxetane], 2-oxaspiro [3.5] non-6-ene, 5-methyl-2-oxaspiro [3.5] non-6-ene, spiro [bicyclo [2. 2.1] Hept-5-ene-2,3'-oxetane], spiro [3-methylbicyclo [2.2.1] hept-5-ene-2,3'-oxetane], 5-methyl-
2-oxaspiro [3.5] nonane, spiro [3-methylbicyclo [2.2.1] heptane-2,3′-oxetane] and the like. These compounds (a) can be used alone or as a mixture of two or more. The compounding amount of the compound (a) in the conductive adhesive composition of the present invention is preferably 1 to 60% by mass, more preferably 5 to 40% by mass.

The compound (b) having at least one oxetanyl group and at least one epoxy group in the same molecule used in the present invention includes, for example, at least one oxetanyl group and at least one epoxy group in the same molecule. And alicyclic alkanes having the same. Compound (b) includes the following. That is, 3-ethyl-3-[(oxiranylmethoxy) methyl] oxetane, 7,8-epoxy-2-oxa-5-
Methyl-spiro [3.5] nonane, 6,7-epoxy-
2-oxa-spiro [3.5] nonane, spiro [5,6
-Epoxynorbornane-2,3'-oxetane], spiro [5,6-epoxy-3-methylnorbornane-
2,3'-oxetane] and the like. Furthermore, 7,8-epoxy-2-oxa-5-methyl-spiro [3.6] decane, 5,6-epoxy-2-oxa-spiro [3.
6] Decane. Among them, the general formula (1)
Compounds represented by the following formulas, for example, 7,8-epoxy-2-oxa-5-methyl-spiro [3.5] nonane and 6,7-epoxy-2-oxa-spiro [3.5] nonane are preferred.

The compound (b) having at least one oxetanyl group and at least one epoxy group in the same molecule can be easily synthesized by a known method,
For example, a synthesis method is described in U.S. Pat. No. 3,388,105.

The compound (b) having at least one oxetanyl group and at least one epoxy group in the same molecule can be used alone or as a mixture of two or more. The compounding amount of the compound (b) in the conductive adhesive composition of the present invention is preferably 1 to 60% by mass, and more preferably 5 to 40% by mass.

The cured film formed from the conductive adhesive composition containing the compound (a) and / or (b) having an oxetanyl group in the molecule has low water absorption, and as a result, has good water resistance. Shows sex. In addition, since the degree of cure shrinkage is small, it has a feature of excellent dimensional stability.

The conductive particles dispersed in the conductive adhesive composition of the present invention include Au, Ag, Ni, Cu, Sb,
There are metal particles such as Sn and solder, particles of a substance having conductivity such as carbon, and particles having these particles or non-conductive glass, ceramics and plastic particles as cores and coated with another conductive material on the surface. Further, a conductive particle having a core as a core, the surface of the core is coated with an insulating layer, and when pressed, the inner core breaks the insulating layer to make contact therewith can be used. These particles may be used alone or in combination as needed.

The compounding amount of the conductive particles is usually 1 to 50% by mass, preferably 4 to 30% by mass, particularly preferably 5 to 10% by mass in the conductive adhesive composition of the present invention. If the amount of the conductive particles is too small, the conductivity may decrease. On the other hand, if the amount is too large, the anisotropy of the conductivity may decrease. For the purpose of improving the dispersibility of the conductive particles, a coupling agent such as a silane coupling agent may be used in combination. The amount of the coupling agent
In the conductive adhesive composition of the present invention, it is usually 1 to 10% by mass, preferably about 2 to 7% by mass.

The compound (c) for initiating cationic polymerization by irradiation with active energy rays and / or heating in the present invention is changed by heating or irradiation with active energy rays such as ultraviolet rays to initiate cationic polymerization such as acid. It can be a compound that produces a substance. Therefore, the compound (c) is a kind of cationic polymerization initiator, and is also called “acid generator” in the art. Hereinafter, in the present invention, the compound (c) is referred to as an acid-generating cationic polymerization initiator.

The acid-generating cationic polymerization initiator promotes the ring-opening cationic polymerization of the compound (a) and / or (b) having an oxetanyl group in the molecule of the present invention by heating or irradiation with light such as ultraviolet rays. The curing of the cured film proceeds smoothly.

The acid-generating cationic polymerization initiator referred to in the present invention is a compound which changes upon heating or irradiation with active energy rays such as ultraviolet rays to produce a substance which initiates cationic polymerization such as an acid. Thus, compounds which are in the acid form from the beginning are not included.

As the acid-generating cationic polymerization initiator, known sulfonium salts, iodonium salts, phosphonium salts,
Examples thereof include diazonium salts, ammonium salts, and ferrocenes. Specific examples are shown below, but the present invention is not limited to these compounds.

Examples of the sulfonium salt-based acid-generating cationic polymerization initiator include bis [4- (diphenylsulfonio)
Phenyl] sulfide bishexafluorophosphate, bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluoroantimonate, bis [4- (diphenylsulfonio) phenyl] sulfide bistetrafluoroborate, bis [4- (diphenylsulfo) Nio) phenyl] sulfide tetrakis (pentafluorophenyl) borate, diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate, diphenyl-4- (phenylthio) phenylsulfonium hexafluoroantimonate, diphenyl-4- (phenylthio) phenylsulfonium tetra Fluoroborate, diphenyl-4- (phenylthio) phenylsulfonium tetrakis (pentafluorophenyl) borate, tri Phenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfo) Nio) phenyl] sulfide bishexafluorophosphate, bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bishexafluoroantimonate, bis [4
-(Di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bistetrafluoroborate, bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfidetetrakis ( Pentafluorophenyl) borate, and the like.

Examples of the iodonium salt-based cationic polymerization initiator include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, diphenyliodonium tetrakis (pentafluorophenyl) borate, and bis (dodecylphenyl). ) Iodonium hexafluorophosphate, bis (dodecylphenyl) iodonium hexafluoroantimonate, bis (dodecylphenyl) iodonium tetrafluoroborate, bis (dodecylphenyl) iodonium tetrakis (pentafluorophenyl) borate, 4-methylphenyl-4- (1 −
Methylethyl) phenyliodonium hexafluorophosphate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium hexafluoroantimonate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium tetrafluoroborate, 4
-Methylphenyl-4- (1-methylethyl) phenyliodonium tetrakis (pentafluorophenyl)
Borate, and the like.

Examples of phosphonium salt-based cationic polymerization initiators include ethyltriphenylphosphonium tetrafluoroborate, ethyltriphenylphosphonium hexafluorophosphate, ethyltriphenylphosphonium hexafluoroantimonate, tetrabutylphosphonium tetrafluoroborate and tetrabutylphosphonium tetrafluoroborate. Butylphosphonium hexafluorophosphate, tetrabutylphosphonium hexafluoroantimonate, and the like.

Examples of the diazonium salt-based cationic polymerization initiator include phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroantimonate, phenyldiazonium tetrafluoroborate, phenyldiazonium tetrakis (pentafluorophenyl) borate, and the like. .

Examples of the ammonium salt-based cationic polymerization initiator include 1-benzyl-2-cyanopyridinium hexafluorophosphate and 1-benzyl-2-phosphate.
Cyanopyridinium hexafluoroantimonate,
1-benzyl-2-cyanopyridinium tetrafluoroborate, 1-benzyl-2-cyanopyridinium tetrakis (pentafluorophenyl) borate, 1-
(Naphthylmethyl) -2-cyanopyridinium hexafluorophosphate, 1- (naphthylmethyl) -2-
Cyanopyridinium hexafluoroantimonate,
1- (naphthylmethyl) -2-cyanopyridinium tetrafluoroborate, 1- (naphthylmethyl) -2-
Cyanopyridinium tetrakis (pentafluorophenyl) borate; and the like.

Examples of the ferrocene-based cationic polymerization initiator include (2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -Fe (II) hexafluorophosphate and (2,4 -Cyclopentadien-1-yl) [(1-methylethyl) benzene]-
Fe (II) hexafluoroantimonate, 2,4-cyclopentadien-1-yl) [(1-methylethyl)
Benzene] -Fe (II) tetrafluoroborate, 2,
4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -Fe (II) tetrakis (pentafluorophenyl) borate, and the like.

Among these acid-generating cationic polymerization initiators, sulfonium salt and iodonium salt-based initiators are preferred from the viewpoints of curing speed, stability and economy. Commercial products include Asahi Denka Kogyo's SP-150, SP-170, CP
-66, CP-77; CYRA manufactured by Union Carbide
CURE-UVI-6990, UVI-6974; CI-2855, CI-2639, manufactured by Nippon Soda Co., Ltd .; San-Aid SI-60, manufactured by Sanshin Chemical Industries; "Irgacure 261"
((2,4-cyclopentadien-1-yl) [(1-methylethyl) manufactured by Ciba Specialty Chemicals)
Benzene] -Fe (II) hexafluorophosphate), "RHODORSIL 207
4 "; (4-methylphenyl-4 manufactured by Rhone Poulin Co.)
-(1-methylethyl) phenyliodonium tetrakis (pentafluorophenyl) borate) and the like.

These acid-generating cationic polymerization initiators are selected from the above-mentioned materials, and can be used alone or in combination of two or more.
The preferred range of the amount of the acid-generating cationic polymerization initiator used is
Although there is no particular limitation, the sum of the compounding amount of the compound (a) having at least one oxetanyl group in the molecule and the compound (b) having at least one oxetanyl group and at least one epoxy group in the same molecule (described later) When a compound capable of cationic polymerization, such as a compound having an epoxy group, is used in combination, the total amount of these compounds is 100 parts by mass.
It is 0.5 to 25 parts by mass, preferably 0.1 to 20 parts by mass. If the addition amount is less than 0.05 parts by mass, sensitivity becomes poor and curing is required, so that extremely large light irradiation energy and prolonged high-temperature treatment are required. Further, even if it is added in excess of 25 parts by mass, the sensitivity is not improved, which is not economically preferable. Conversely, the amount remaining as an uncured component in the cured conductive adhesive layer is increased, and the cured physical properties may be reduced.

As the compound (d) having one or more epoxy groups in the molecule and not having an oxetanyl group, a known and commonly used epoxy compound can be used. When an epoxy compound is added to the conductive adhesive composition of the present invention, the heat resistance and chemical resistance of the obtained cured film are further improved. This epoxy compound is not particularly limited as long as it has one or more epoxy groups in one molecule.

Specifically, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether,
Bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether, novolak epoxy resin (for example, phenol novolak epoxy resin, cresol novolak epoxy resin, Brominated phenol novolak type epoxy resin), hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether,
Triglycidyl isocyanurate and the like can be used.

Further, as the aliphatic epoxy compound,
(3,4-epoxycyclohexyl) methyl-3 ′,
4'-epoxycyclohexylcarboxylate, 2-
(3,4-epoxycyclohexyl-5,5-spiro-
3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclohexylmethyl) adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-
6-methylcyclohexylmethyl) adipate, 3,4
-Epoxy-6-methylcyclohexyl-3 ', 4'-
Epoxy-6'-methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylenebis (3,4-epoxycyclohexane) Carboxylate).

Further, dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether,
1 for aliphatic polyhydric alcohols such as glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, ethylene glycol, propylene glycol, and glycerin
Polyglycidyl ethers of polyether polyols obtained by adding one or more alkylene oxides; diglycidyl ethers of aliphatic long-chain dibasic acids; monoglycidyl ethers of aliphatic higher alcohols; butyl glycidyl ether; Phenyl glycidyl ether, cresol glycidyl ether, nonylphenyl glycidyl ether, glycidyl methacrylate;
Phenol, cresol, butylphenol or monoglycidyl ethers of polyether alcohol obtained by adding alkylene oxide thereto; glycidyl esters of higher fatty acids; epoxidized soybean oil; butyl epoxystearate, octyl epoxystearate, epoxidized ani Oil, epoxidized polybutadiene and the like can be mentioned.

The compound (d) having one or more epoxy groups in the molecule and no oxetanyl group can be used alone or as a mixture of two or more. The compounding amount of the compound (d) (the total amount when two or more kinds are used in combination) is 1 to 100 parts by mass of the compound (a) and the compound (b) having an oxetanyl group in the molecule in the present invention. It is preferably from 10,000 to 10,000 parts by mass,
000 parts by weight are particularly preferred.

In the present invention, the following cationically polymerizable monomers can also be added to the conductive adhesive composition. The cationically polymerizable monomer is a compound which initiates a polymerization initiation reaction or a crosslinking reaction by an acid generated from an acid-generating type cationic polymerization initiator, and includes (a), (b), (c), and (d).
Are classified as compounds other than. For example, oxolane compounds such as tetrahydrofuran and 2,3-dimethyltetrahydrofuran; trioxane, 1,3-dioxolane,
Cyclic acetal compounds such as 1,3,6-trioxanecyclooctane; cyclic lactone compounds such as β-propiolactone and ε-caprolactone; ethylene sulfide;
Thiirane compounds such as 1,2-propylene sulfide and thioepichlorohydrin; Thietane compounds such as 3,3-dimethylthiethane; vinyl ether compounds such as ethylene glycol divinyl ether, triethylene glycol divinyl ether, and trimethylolpropane trivinyl ether; Spiro orthoester compounds which are reaction products of epoxy compounds and lactones; ethylenically unsaturated compounds such as vinylcyclohexane, isobutylene and polybutadiene; cyclic ether compounds; cyclic thioether compounds; vinyl compounds.

These cationically polymerizable monomers can be used alone or in a combination of two or more.

The compound (e) having a radical polymerizable unsaturated group is added to the conductive adhesive composition of the present invention in a range that does not impair the object of the present invention in order to improve the photocurable (active energy ray) curability. It is also possible to add. The compound (e) is not particularly limited, but a (meth) acrylic ester-based known and commonly used radically polymerizable monomer can be used. Specifically, methyl (meth) acrylate,
Ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth)
Acrylate, cyclohexyl (meth) acrylate,
Monofunctional (meth) such as phenoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, benzyl (meth) acrylate, and ethylene glycol mono (meth) acrylate ) Acrylate compounds; ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, polyfunctional epoxy ( (Meth) acrylate resins, polyfunctional urethane (meth) acrylate resins, and the like.

The compound (e) is added in an amount of 5 to 200 parts by mass, preferably 1 to 100 parts by mass of the total of the cationically polymerizable compounds (a) and / or (b), (c) and (d).
0 to 100 parts by mass. If the addition amount exceeds 200 parts by mass, the dryness to the touch becomes poor. In addition, since the rate of crosslinking of the (meth) acrylic group increases during curing, the heat resistance and chemical resistance of the obtained cured film are reduced.

It is desirable to add a photo-radical initiator (f) in order to smoothly promote the radical polymerization of the above-mentioned compound having a radical-polymerizable unsaturated group. it can. Here, “light” means radiation such as visible light, ultraviolet light, far ultraviolet light, X-rays, and electron beams. Examples of the photo-radical initiator (f) include benzoin, benzoin ethyl ether,
Benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl- 1-phenylpropan-1-one, 1-
Hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (manufactured by Ciba Specialty Chemicals; Irgacure 907), 4- (2-hydroxyethoxy) phenyl- 2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4′-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone,
t-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, p-dimethylamine benzoate, 2,4,6- Trimethylbenzoyldiphenylphosphine oxide (BASF
(Rucillin TPO), initiator containing bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide (Ciba Specialty Chemicals; Irgacure 1700, 149, 180)
0), bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (manufactured by Ciba Specialty Chemicals, Inc .; Irgacure 819). These can be used alone or as a mixture of two or more.

The amount of the photo-radical initiator (f) used is determined by the amount of the compound (e) 1 having a radical polymerizable unsaturated group in the composition.
0.007 to 0.5 mol can be used per equivalent.

A solvent can be added to the conductive adhesive composition of the present invention as a viscosity modifier for adapting to the method of use. Specifically, ethylene glycol monoalkyl ether or acetates thereof; diethylene glycol mono or dialkyl ethers; propylene glycol monoalkyl ether or acetates thereof;
Dipropylene glycol mono- or dialkyl ethers; well-known such as methyl carbitol, butyl carbitol, butyl cellosolve acetate, carbitol acetate, ethyl methyl ketone, cyclohexane, toluene, xylene, tetramethylbenzene, petroleum ether, petroleum naphtha, solvent naphtha, etc. Organic solvents; or additives well-known in the art such as plasticizers, solvents, and the like, and these can be used alone or in combination of two or more.

The amount of these solvents is based on 100 parts by weight of the total of the components (a) to (f) in the adhesive composition of the present invention, or the components appropriately selected and used among them, and the conductive particles. The amount is 0 to 2000 parts by mass, and can be appropriately selected depending on the application method.

The conductive adhesive composition of the present invention has heat resistance,
An inorganic filler may be blended for the purpose of improving properties such as adhesion and hardness. Specifically, powders of fused silica powder, crystalline silica powder, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, aluminum nitride, boron nitride, beryllium, zirconia, talc, clay, aluminum hydroxide, etc., Or spherical beads of these,
One or more kinds of single crystal fibers such as potassium titanate, silicon carbide, silicon nitride, and alumina, glass fibers, and the like can be mixed and used. Among these inorganic fillers, fused silica is preferred from the viewpoint of reducing the coefficient of linear expansion, and alumina is preferred from the viewpoint of high thermal conductivity. The amount used is in a range that does not impair the conductivity. It is preferable that the inorganic filler is sufficiently mixed in advance.

When polymerizing the conductive adhesive composition of the present invention with ultraviolet rays, which is one of the active energy rays, a sensitizer may be used in order to increase the polymerization rate. Sensitizers used for such purposes include pyrene, perylene, 2,4-diethylthioxanthone,
4-dimethylthioxanthone, 2,4-dichlorothioxanthone, phenothiazine and the like. When the sensitizer is used in combination, the amount used is preferably in the range of 0.1 to 100 parts by mass with respect to 100 parts by mass of the photoacid-generating cationic polymerization initiator.

If necessary, known and conventional coloring agents such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black; silicone-based, fluorine-based, and polymer -Based antifoaming agents; leveling agents; adhesion-imparting agents such as imidazole-based, thiazole-based, triazole-based, and silane coupling agents; antimony trioxide, phosphate esters, red phosphorus, and nitrogen-containing compounds including melamine resins. And other known additives such as a flame retardant such as silicone oil and silicone rubber powder, a stress relieving agent such as silicone oil and silicone rubber powder, and an ion trapping agent such as hydrotalcite and antimony-bismuth.

The conductive adhesive (conductive paste) of the present invention
Is prepared by mixing the constituents such as the compounds (a) and (b) described above, and further performing a kneading treatment using a known and commonly used mixing apparatus, for example, a three-roll mill, and then degassing under reduced pressure if necessary. can do. The mixing apparatus is not particularly limited as long as it can uniformly mix the constituent materials, but it is necessary to select the mixing apparatus in consideration of the viscosity of the composition, the dispersibility of the conductive particles, and the like. As the mixing device, for example, a high-speed mixer, a kneader, a homomixer, a planetary mixer, or the like can be used.

The conductive adhesive thus produced can be used for bonding various electronic parts, coating, forming electrodes by printing, forming circuits, and the like.

The conductive adhesive film of the present invention is prepared by mixing the above-mentioned components (a) and (b),
Further, a kneading process using a known and customary mixing device, for example, a three-roll mill, and then, if necessary, preparing a coating solution by defoaming under reduced pressure, and then applying the coating solution on a support such as a polymer film, For example, it can be manufactured by blowing and drying to form a coating film. The above-mentioned solvent can be added to the coating liquid as needed. As the mixing device, for example, a high-speed mixer, a kneader, a homomixer, a planetary mixer, or the like can be used. The coating can be performed using, for example, a knife coater, a bar coater, a roll coater, a die coater, or the like.

The conductive adhesive film thus manufactured can be used for electrical connection between conductors. For example, the conductive adhesive film of the present invention can be used to electrically connect a conductor provided on each surface of two substrates, as follows.

First, the conductive adhesive film of the present invention is disposed so as to be in contact with the conductor of one of the substrates, and the adhesive film is cured by irradiation with active energy rays and / or heating. This step is convenient for temporarily bonding the substrate and the adhesive film when the surface of the conductive adhesive film before curing has tackiness. When one surface of the adhesive film is covered with a transparent support, the adhesive film may be irradiated with active energy rays through the support. In the case where the support absorbs the active energy ray, irradiation of the active energy ray is performed after the support is peeled off.

Next, the other substrate is placed so that the conductor of the substrate is in contact with the activated adhesive film,
The thermocompression bonding is performed at a temperature of 120 ° C. or less, for example, 70 to 120 ° C. The open time from activation to thermocompression bonding is usually from several seconds to 24 hours. The thermocompression bonding can be performed by, for example, an iron, a hot damper, or a heating roll. The strength of the pressure is generally 1 so that sufficient electrical continuity is obtained after connection.
About 5 to 5 MPa (10 to 50 kg / cm ² ) is appropriate. Further, the pressure bonding time is sufficient for 10 to 30 seconds, but may be longer.

The conductive adhesive composition of the present invention can be polymerized (cured) by irradiation with active energy rays and / or heating. The term “active energy ray” as used herein refers to ultraviolet rays, X-rays, electron beams, γ-rays, and the like. As a light source for irradiating ultraviolet rays, a metal halide lamp, a mercury arc lamp, a xenon arc lamp, a fluorescent lamp, a carbon arc lamp, a tungsten-halogen copying lamp, sunlight, and the like can be given.

The irradiation conditions for curing are usually such that the dose is about 1
0 to 1,000 mJ / cm ² , preferably about 10 to 50
0 mJ / cm ² , more preferably about 10 to 100 mJ /
cm ² is suitable. If heating is used, curing may be at room temperature (about 25 ° C.) to 250 ° C., preferably about 50 to 200 ° C., more preferably about 75 to 150 ° C. for about 1 to 60 minutes, preferably about 5 to 30 minutes, Preferably, the reaction may be performed under the conditions of about 10 to 20 minutes.

[0053]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The “parts” in Examples and Comparative Examples
Represents parts by mass unless otherwise specified.

Of the materials used in Examples and Comparative Examples, commercial products were used without purification.

Compound not commercially available, ie, 7,8-
Epoxy-2-oxa-5-methylspiro [3.5] nonane (ECHO) was synthesized by the present inventors as described below with reference to the method described in US Pat. No. 3,388,105.

<Synthesis of 7,8-epoxy-2-oxa-5-methyl-spiro [3.5] nonane> 1) Synthesis of 2-methyl-4-cyclohexene-1,1-dimethanol Three-necked flask Of butadiene and crotonaldehyde
327 g of 2-methyl-4-cyclohexene-1-carbaldehyde, which is a Diels-Alder reaction product, 600 ml of methanol and 729 g of 37% formalin water were added thereto, and the solution was heated to 60 ° C. while stirring. Subsequently, a solution in which 252 g of KOH was dissolved in 600 ml of distilled water was added dropwise over 2 hours. After stirring was continued for 7 hours, the reaction solution was concentrated under reduced pressure to obtain a two-layer residue. The oil layer concentrated to about 150 ml was washed with 300 ml of distilled water. After concentrating the oil layer under reduced pressure, 50 mg of 3,5-di (t-butyl) -4-hydroxytoluene (BHT) was added, and the mixture was distilled under reduced pressure to obtain 2-methyl-4-cyclohexene-1,1, a colorless crystal. 311 g of dimethanol (82% yield) were obtained.

2) 2-methyl-4-cyclohexene-
Synthesis of 1,1-dimethanol cyclic carbonate 3-methyl-4-cyclohexene-
310 g (1.99 mol) of 1,1-dimethanol, 894 g of dimethyl carbonate (DMC) and 0.9 g of potassium carbonate
3 g was charged, the temperature was raised to 90 ° C., and the mixture was refluxed for 4 hours. The reaction solution was returned to room temperature, and potassium carbonate was separated by filtration. After adding 120 mg of BHT, the remaining DMC and methanol were removed under reduced pressure of 2 kPa (15 mmHg), followed by distillation under reduced pressure to obtain 2-methyl-4-cyclohexene-1,1-dimethanol cyclic which was colorless crystals at room temperature. 326 mg (yield: 89.4%) of a carbonate was obtained.

3) 2-oxa-5-methylspiro [3.
5] Synthesis of nona-7-ene 2-methyl-4-cyclohexene-
1,1-dimethanol cyclic carbonate 321.15
g, BHT 642 mg (0.2% by mass), LiCl 1.9
3 g was charged and heated and stirred at 275 ° C. using a mantle heater. Immediately after about 8 kPa (60 mmH
g) Pull out the system under reduced pressure and wait until no more
Heating was continued for hours. Add 600 mg of BHT to the product,
The mixture was distilled under reduced pressure to obtain 187 g of 2-oxa-5-methylspiro [3.5] non-7-ene which was a colorless transparent liquid (yield: 7).
1%).

4) 7,8-epoxy-2-oxa-5-
Synthesis of methyl-spiro [3.5] nonane 50 g of 2-oxa-5-methylspiro [3.5] non-7-ene was dissolved in 150 ml of dichloromethane and charged into the reactor. A suspension of 93.7 g of m-chloroperbenzoic acid in 400 ml of dichloromethane was added dropwise over 1 hour so that the reaction solution did not exceed 40 ° C. The precipitated m-chlorobenzoic acid was separated by filtration and washed well with cold dichloromethane. 15.0 g of calcium hydroxide in the organic layer
Was added and stirred for 30 minutes, and the precipitated crystals were separated by filtration and washed with cold dichloromethane. The organic layer was washed with 5% NaHSO ₄
After washing with water and a saturated saline solution, the mixture was concentrated and distilled under reduced pressure at room temperature to give a colorless semisolid 7,8-epoxy-2-oxa-
38.1 g (yield 73.7%) of 5-methyl-spiro [3.5] nonane was obtained.

Examples 1 to 5 and Comparative Example 1 Curability of each composition containing an epoxy resin (Epicoat 828) and an oxetane compound (ECHO or XDO) having the composition shown in Table 1 after curing at 100 ° C. for 5 minutes. Compared. From the results shown in Table 1, it can be seen that both the oxetane compound alone and the case where the oxetane compound is mixed with the epoxy resin cures much faster than the composition containing only the epoxy resin as the main component.

[0061]

[Table 1]

Epoxy resin: Epikote 828 (manufactured by Yuka Shell Co., Ltd.) Oxetane compound: ECHO: 7,8-epoxy-2-oxa-5-methyl-spiro [3.5] nonane XDO: 1,4-bis [( 3-ethyl-3-oxetanylmethoxy) methyl] benzene (manufactured by Toagosei Co., Ltd.) Cationic curing agent: CP66 (manufactured by Adeka) 2-butenyltetramethylenesulfonium hexafluoroantimonate

Examples 6 and 7 Conductive Adhesives (Conductive Pastes) Various conductive adhesives were prepared, and their curability and adhesive strength were measured. 13 g of Epicoat 1004 (manufactured by Yuka Shell Co., Ltd.) as an epoxy resin and ECHO as an oxetane compound
Or 2 g of XDO and 15 g of methyl cellosolve acetate
At 100 ° C. Cool this to room temperature,
0.023 g of 3,5-dimethyl-4-acetoxyphenylsulfonium hexafluoroantimonate and 9 g of silver powder were added, mixed, and kneaded with a three-roll mill to produce a conductive adhesive.

These conductive adhesives were tested for curability and adhesive strength. As for the curability, a cured state after 10 minutes at 150 ° C. was observed. The adhesive strength was measured by bonding a 2.0 × 2.0 mm silicone element on a silver-plated lead frame (copper), curing at 150 ° C. for 1 hour, and then using a tension gauge at 25 ° C. The results are shown in Table 2.

Comparative Example 2 A conductive adhesive was prepared in the same manner as in Examples 6 and 7, except that 13 g of Epicoat 1004 and 15 g of Epicoat 100 were used instead of 13 g of oxetane. The results are shown in Table 2. In Examples 6 and 7, which contain ECHO or XDO, which is an oxetane compound, it can be seen that the adhesive strength is the same as in Comparative Example 8, which contains the epoxy resin, but the curability is significantly improved.

[0066]

[Table 2]

Examples 8 to 11 and Comparative Example 3 Conductive Adhesive Film The adhesive properties and connection resistance of the prepared conductive adhesive films were measured and compared between the epoxy resin alone and the system mixed with the oxetane compound. As shown in Table 3, the epoxy resin, the oxetane compound ECHO, the phenoxy resin and the cationic polymerization initiator were mixed with 30 g of toluene and 3 g of ethyl acetate.
Dissolved in 0 g. 4 g of nickel-based conductive particles (specific gravity: 2.0) having a polystyrene core having an average particle diameter of 10 μm
Was added and dispersed.

Each composition was applied to a fluororesin film having a thickness of 80 μm and dried by blowing air at room temperature to prepare a conductive adhesive film having a thickness of 25 μm. Using these films, line width 100 μm, pitch 200 μm, thickness 35
A flexible substrate having 250 μm copper circuits and a 0.5 mm thick polycarbonate plate having a thin film of indium tin oxide (ITO) formed on the entire surface at 130 ° C. and 1.5
The connection was made over a width of 3 mm by thermocompression bonding at 20 MPa for 20 seconds. At this time, the adhesive surface of the conductive adhesive film was previously stuck on the polycarbonate plate,
Temporarily connected by heating and pressure bonding for 5 seconds at Pa, peeling off the fluororesin film and connecting to the flexible substrate. After the circuit was connected, the state of adhesion was observed, and the resistance between adjacent circuits of the flexible substrate including the connection was measured with a multimeter. The composition and results are shown in Table 3.

[0069]

[Table 3]

Epicoat 828: bisphenol A type epoxy resin (manufactured by Yuka Shell) Celloxide 2021: alicyclic epoxy resin (manufactured by Daicel Chemical Industries, Ltd.) PKHA: phenoxy resin (manufactured by UCC) Cationic polymerization initiator A: p- Acetoxyphenylbenzylmethylsulfonium hexafluorophosphate Cationic polymerization initiator B: p-hydroxyphenyl-P-
Nitrobenzylmethylsulfonium hexafluorophosphate

Examples 8 to 11 were all the same as Comparative Example 3 in both the adhesiveness and the connection resistance. Therefore,
It has been clarified that the adhesion and the connection resistance are not impaired even when the amount of the oxetane compound is increased.

Example 12 Conductive Adhesive Film The adhesiveness and connection resistance of a conductive adhesive film prepared by mixing a radical polymerizable resin were measured. A conductive adhesive film having the composition shown in Table 4 was produced in the same manner as in Example 8.
The above-mentioned conductive adhesive film was heat-pressed at 70 ° C. and 0.5 MPa for 5 seconds on a 0.5 mm-thick polycarbonate plate having a thin film of indium tin oxide (ITO) formed on the entire surface, and temporarily connected to form a fluororesin film. Peeled off. This was irradiated with ultraviolet rays of 1000 mJ / cm ² from a high-pressure mercury lamp. A flexible substrate having 250 copper circuits having a line width of 100 μm, a pitch of 200 μm, and a thickness of 35 μm is placed on the conductive adhesive film at 110 ° C. and 1.5 MPa
a. Heated and pressed at a for 20 seconds and connected over a width of 3 mm.
After the circuit was connected, the state of adhesion was observed, and the resistance between adjacent circuits of the flexible substrate including the connection was measured with a multimeter. The composition and the results are shown in Table 4.

As is clear from comparison with the results shown in Table 3,
Even when a radical polymerizable compound is further added and activated by ultraviolet light, low-temperature curing becomes possible without affecting adhesiveness and connection resistance.

[0074]

[Table 4]

[0075]

Industrial Applicability The conductive adhesive composition of the present invention can be sufficiently cured by a small amount of active energy ray irradiation or heating at a low temperature for a short time, and has excellent adhesiveness and electrical properties. It is useful for providing an adhesive film.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 1/20 H01B 1/20 DF Term (Reference) 4J004 AA01 AA11 AA13 AB03 AB05 AB06 AB07 BA02 CC02 FA05 4J040 EC261 EE031 HB43 HB44 HC14 HD13 JA09 JB01 JB02 JB07 JB08 KA03 KA13 KA32 LA09 NA20 PA23 5G301 DA03 DA42 DD03 DD08

Claims (19)

[Claims] 1. A conductive adhesive composition comprising a compound (a) having at least one oxetanyl group in a molecule and conductive particles. 2. A conductive adhesive composition comprising: a compound (b) having at least one oxetanyl group and at least one epoxy group in the same molecule; and conductive particles. 3. A compound (a) having at least one oxetanyl group in the molecule, a compound (b) having at least one oxetanyl group and at least one epoxy group in the same molecule, and conductive particles. Characteristic conductive adhesive composition. 4. The conductive adhesive according to claim 2, wherein the compound (b) having at least one oxetanyl group and at least one epoxy group in the same molecule is an alicyclic alkane. Composition. 5. The conductive adhesive composition according to claim 4, wherein the alicyclic alkane is a compound represented by the general formula (1). Embedded image Wherein R is a hydrogen atom or a methyl group, and m is 0 to 2
N is 2 when m is 0, and 1 otherwise.) 6. The compound represented by the general formula (1) is 7,8
-Epoxy-2-oxa-5-methyl-spiro [3.
5] The conductive adhesive composition according to claim 5, which is nonane and / or 6,7-epoxy-2-oxa-spiro [3.5] nonane. 7. The conductive adhesive composition according to claim 1, further comprising a compound (c) for initiating cationic polymerization by irradiation with active energy rays and / or heating. 8. The compound according to claim 7, wherein the compound (c) which initiates cationic polymerization by irradiation with active energy rays and / or heating is at least one selected from a sulfonium salt, an iodonium salt and a diazonium salt. Conductive adhesive composition. 9. A compound (d) having at least one epoxy group and not having an oxetanyl group.
The conductive adhesive composition according to any one of the above. 10. The conductive adhesive composition according to claim 1, comprising a compound (e) having a radically polymerizable unsaturated group. 11. The conductive adhesive composition according to claim 1, further comprising a photo-radical polymerization initiator (f). 12. A conductive adhesive comprising the conductive adhesive composition according to claim 1. 13. An electronic component and device manufactured using the conductive adhesive according to claim 12. 14. A printed circuit manufactured using the conductive adhesive according to claim 12. 15. A conductive adhesive film comprising the conductive adhesive composition according to claim 1. 16. An electronic component and device manufactured using the conductive adhesive film according to claim 15. 17. A printed circuit manufactured using the conductive adhesive film according to claim 15. 18. The method for curing a conductive adhesive composition according to claim 1, wherein the conductive adhesive composition is cured by irradiation with active energy rays and / or heating. . 19. The method for curing a conductive adhesive composition according to claim 18, wherein the active energy rays are ultraviolet rays.