JPH11256117A - Anisotropically electroconductive photocurable adhesive sheet and junction of electrical parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject adhesive sheet capable of accomplishing anisotropically electroconductive connection through merely pressure contact bonding, curable without the need of any heat treatment, thereby capable of raising electrical connection reliability and also usable in the connection of parts or members with inadequate heat resistance, and to provide a method for the junction of electrical parts using the above adhesive sheet. SOLUTION: This adhesive sheet comprises (A) a polymer, (B) a photocurable resin, (C) a curing catalyst intended for curing the resin B, and (D) electroconductive particles, having tackiness. The objective method for the junction of electrical parts using the above adhesive sheet comprises irradiating the above sheet with light to effect the aimed junction of two electrical, parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anisotropically conductive photo-curable pressure-sensitive adhesive sheet and a method for joining electric parts, and more particularly, to an anisotropically conductive photo-curable pressure-sensitive adhesive sheet having an adhesive property sufficient to achieve anisotropically conductive connection only by pressing. The present invention relates to an anisotropically conductive photo-curable pressure-sensitive adhesive sheet which can be cured by heat and without heat treatment by light irradiation, and which can enhance the reliability of anisotropically conductive connection, and a method for joining electric components.

[0002]

2. Description of the Related Art As electric and electronic equipment has become more sophisticated, smaller, and thinner, the size of electrical connections has been reduced. For example, there is an increasing need to join fine electrical circuits together or to join a fine electrical circuit and a chip component having many connection pins. When joining such very small electric circuit parts or making electrical connection in a very narrow range, it is difficult to ensure insulation from surrounding parts that should not be electrically connected. It may be.

In order to solve the above-mentioned problems, various anisotropic conductive bonding materials have been proposed. An anisotropic conductive bonding material is a bonding material that has conductivity in one direction but does not have conductivity in another direction. Such an anisotropic conductive bonding material is widely used, for example, for connection between a liquid crystal display panel and a TCP (tape carrier package) in a liquid crystal display device, or for electrical connection between a flexible printed circuit board (FPC) and a TCP. ing.

[0004] Conventional anisotropic conductive bonding materials include a film-shaped anisotropic conductive film (JP-A-60-84718) in which conductive particles are dispersed in a thermoplastic resin.
Alternatively, an anisotropic conductive adhesive formed by dispersing conductive particles in a thermoplastic resin to form a paste (JP-A-62-15474).
No. 6) has been studied.

[0005] In the anisotropic conductive film based on the above-mentioned thermoplastic resin, the film is sandwiched between members to be joined, and the film is melted by heating and pressing, and further cooled to cool the members. Is achieved. Since this type of anisotropic conductive film is based on a thermoplastic resin, heating and pressing can be performed in a short time, that is, bonding can be performed in a short time. However, since the matrix of the joining portion is made of the thermoplastic resin as described above, there is a limit to the heat resistance of the joining portion.

On the other hand, in the case of an anisotropic conductive adhesive based on a thermosetting resin (Japanese Patent Application Laid-Open No. 61-74205), the adhesive is heated to about 150 ° C. to promote thermosetting. Thereby, the adhesive strength and the reliability of the connection are improved. Further, the cured product is also excellent in heat resistance and chemical resistance.

However, in order to complete the curing, 1
Since it is necessary to heat at a temperature of about 50 ° C. for a certain period of time, it cannot be used for joining members or components having low heat resistance or members or components having insufficient thermal dimensional stability.

Japanese Patent Application Laid-Open No. 9-291259 discloses a low-temperature curable anisotropic conductive adhesive for solving this problem. However, even with the anisotropic conductive adhesive described in this prior art, although the heating temperature is lowered, it is still necessary to heat it at a high temperature of about 90 ° C. It was not enough to use for a member with insufficient properties.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above-mentioned disadvantages of the prior art, to achieve an anisotropic conductive connection only by crimping, and to cure without heat treatment. Anisotropically conductive photo-curable pressure-sensitive adhesive sheet that can be used to increase the reliability of electrical connection and can be used to connect parts and members with insufficient heat resistance, and the anisotropically conductive photo-curable pressure-sensitive adhesive An object of the present invention is to provide a method for joining electric components using a sheet.

[0010]

Means for Solving the Problems The invention according to claim 1 has been made to achieve the above object, and comprises a polymer (A), a photocurable resin (B), and the photocurable resin. It comprises a curing catalyst (C) for curing a conductive resin and conductive particles (D), and is characterized by having adhesiveness.

In the invention according to claim 2, the polymer (A)
Is a (meth) acrylic polymer, the photocurable resin (B) is a resin having at least one cationically polymerizable group in one molecule, and the curing catalyst (C) is a photocationic polymerization initiator. I have.

According to the third aspect of the present invention, an epoxy resin is used as the resin having at least one cationically polymerizable group in one molecule. In the invention described in claim 4, the photocurable resin (B) is 5 to 5000 parts by weight and the conductive particles (D) are 100 parts by weight of the polymer (A).
In a proportion of 0.1 to 2000 parts by weight.

According to a fifth aspect of the present invention, there is provided a method for bonding an electric component, wherein the anisotropic conductive photo-curable pressure-sensitive adhesive sheet according to any one of the first to fourth aspects is used to electrically connect two electric components. Upon connection, the anisotropic conductive light post-curing adhesive sheet is irradiated with light.

In the invention according to claim 6, as the light for curing, light containing a component having a wavelength in the range of 200 to 800 nm is used. Hereinafter, details of the present invention will be described.

[Polymer (A)] The polymer (A) used in the invention of claim 1 may be compatible with the photocurable resin (B), or may be compatible with the photocurable resin (B). The molecular weight is preferably as large as possible as long as it does not cause macro phase separation. Here, the macro phase separation refers to a polymer (A),
A phenomenon in which the photocurable resin (B) completely separates into phases,
This refers to separation in a state in which one or both of the polymer (A) and the photocurable resin (B) has transparency, and is a state different from a state where the polymer is merely clouded by microphase separation.

When the polymer (A) is mixed with the photocurable resin (B), the catalyst (C) and the conductive particles (D) to form a sheet, the polymer (A) exhibits a sufficient cohesive force and It is not particularly limited as long as it can exhibit adhesiveness.
Therefore, the polymer (A) may be appropriately selected according to the photocurable resin (B), the catalyst (C) and the conductive particles (D) to be used.

The molecular weight of the polymer (A) is preferably large, and particularly preferably the one having a weight average molecular weight of about 200,000 to 5,000,000. When the weight average molecular weight is less than 200,000, the cohesive force of the anisotropically conductive photo-curable pressure-sensitive adhesive sheet is insufficient, so that stringing may occur at the time of application and peeling may occur. When the weight average molecular weight exceeds 5,000,000, the viscosity of the composition containing the polymer (A) and the photocurable resin (B) becomes high, and it may be difficult to form the composition into a sheet.

Examples of the polymer (A) include (meth)
Acrylic polymers, polyesters, polyurethanes, silicones, polyethers, polycarbonates, polyvinyl ethers, polyvinyl chloride, polyvinyl acetate, vinyl ester polymers, polyisobutylene, polystyrene, polybutadiene, polyisoprene, polyacrylonitrile, etc. Also, copolymers and modified polymers based on these can be used. Further, as the polymer (A), two or more of the above-mentioned various polymers may be used in combination.

Preferably, it is excellent in weather resistance and tackiness,
(Meth) acrylic polymers are preferably used. The (meth) acrylic polymer includes a homopolymer composed of at least a (meth) acrylate, a copolymer composed of two or more (meth) acrylates, a (meth) acrylate and a copolymer thereof. Copolymers with a vinyl monomer having a possible unsaturated bond can be used, and two or more of these may be used in combination. Here, (meth) acryl is used as a generic term for acrylic and methacryl.

The method for producing the (meth) acrylic polymer is not particularly limited, either, and may be any of those produced by known appropriate polymerization methods such as radical polymerization, anion polymerization, coordination polymerization, and photopolymerization. Can be used.
The structure of the (meth) acrylic polymer is, for example, a homopolymer structure, a random copolymer structure,
Block copolymer structure, alternating copolymer structure, stereoregular structure, hyperbranched structure, star structure, dendritic structure, ladder structure,
Examples of suitable structures such as a cyclic structure and a helical structure can be given, and there is no particular limitation.

More specifically, examples of the above (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, ter
t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, isomyristyl (meth) acrylate, stearyl (Meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, hexane Diol di (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate , Polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate , Dipentaerythritol hexa (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (Meth) acrylate, 2
-Hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 3-hydroxy-3-methylbutyl (meth) acrylate, 2-hydroxy-3
Phenoxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, 2-[(meth) acryloyloxy] ethyl-2-hydroxyethylphthalic acid, 2-[(meth) acryloyloxy] ethyl-2-hydroxypropylphthalate acid,

[0022]

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[0030]

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[0036]

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Although there is no particular limitation,

The vinyl monomer having an unsaturated bond copolymerizable with the (meth) acrylic acid ester is not particularly limited.
Acrylic acid, maleic anhydride, maleimide derivative, (meth) acrylonitrile, N-vinylpyrrolidone, N-acryloylmorpholine, N-vinylcaprolactone,
N-vinylpiperidine, N-vinylformamide, N-
Vinylacetamide, styrene, indene, α-methylstyrene, p-methylstyrene, p-chlorostyrene,
p-chloromethylstyrene, p-methoxystyrene, p
-Tert-butoxystyrene, divinylbenzene, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl benzoate, vinyl cinnamate and derivatives thereof.

The above-mentioned (meth) acrylic acid ester and the vinyl monomer having an unsaturated bond copolymerizable with the (meth) acrylic acid ester may be used in combination of two or more kinds.

[Photocurable Resin (B)] In the invention of the first aspect, the photocurable resin (B) is not particularly limited as long as it is a resin that is cured by irradiating light. The photocurable resin includes, for example, an acrylic oligomer resin selected from epoxy acrylate, urethane acrylate, polyester acrylate, copolymer acrylate, polybutadiene acrylate, silicone acrylate, amino resin acrylate; a compound having a vinyl ether group and a maleimide group A maleimide resin obtained by combining a compound having a double bond; an thiol-based resin obtained by combining a compound having a double bond with a polythiol; a vinyl ether having a vinyloxy group in a resin selected from urethane vinyl ether, polyester vinyl ether, and polyfunctional vinyl ether oligomer Resin; a resin having a cyclic ether such as an epoxy group or an oxetanyl group in the resin. These resins may be used in combination of two or more.

More preferably, a resin having at least one cationically polymerizable group in one molecule is used because of its excellent curing reactivity after light irradiation. Examples of the resin having at least one cationically polymerizable group in one molecule include a vinyl ether-based resin and an epoxy-based resin, and more preferably, adhesion after curing, weather resistance, and chemical resistance. Epoxy resin is used because of its excellent heat resistance.

The epoxy resin is not particularly limited, but examples thereof include bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, bisphenol F epoxy resin, novolak epoxy resin, and aliphatic cyclic epoxy resin. Resins, brominated epoxy resins, rubber-modified epoxy resins, urethane-modified epoxy resins, glycidyl ester compounds, epoxidized soybean oil, epoxidized elastomers, and the like may be used, and a plurality of these may be used in combination.

[Curing Catalyst (C)] As the above curing catalyst (C), an appropriate catalyst can be used according to the curing reaction mode when curing the photocurable resin (B), and it is particularly limited. Do not mean. For example, when an acrylic oligomer resin is used as the photocurable resin, a photoradical polymerization initiator is selected as the curing catalyst (C), and as the photocurable resin, a vinyl ether-based resin having a cationic polymerizable group or When an epoxy resin is used, a cationic photopolymerization initiator is used as the catalyst (C). When an epoxy resin is used as the photocurable resin (B), a photobase catalyst or a photoanion catalyst may be used as the curing catalyst (C).

Examples of the photo-radical polymerization initiator include 4-phenoxydichloroacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 4- (2-hydroxyethoxy) phenyl (2-hydroxy -2-propyl) ketone, α-hydroxy-
acetophenone derivative compounds such as α, α′-dimethylacetophenone, methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone; benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether and benzoin isobutyl ether Ketal derivative compounds such as benzyldimethyl ketal; benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone,
Benzophenone derivative compounds such as hydroxybenzophenone; thioxanthone, 2-chlorothioxanthone,
Such as 2-methylthioxanthone, 2,4-dimethylthioxanthone, 2-isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone; Thioxanthone derivative compounds; halogenated ketones; acylphosphine oxides; acylphosphonates;
Examples thereof include (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, but are not particularly limited. Further, a plurality of photoradical polymerization initiators may be used in combination.

The cationic photopolymerization initiator is not particularly limited as long as it is a compound which can be activated by light irradiation and induce cationic polymerization. Preferably, a compound having a low thermocatalytic activity at around 20 to 100 ° C. is preferable for enhancing storage stability. Examples of such preferred cationic photopolymerization initiators include iron-allene complex compounds, aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, and pyridinium salts.

More specifically, for example, Optomer SP
-150 (manufactured by Asahi Denka Kogyo), Optmer SP151
(Asahi Denka Kogyo), Optmer SP171 (Asahi Denka Kogyo), Optmer SP-170 (Asahi Denka Kogyo), UVE-1014 (General Electronics), CD-1012 (Sartomer), Sun Aid SI-60L (manufactured by Sanshin Chemical Industries), Sun Aid SL-
80L (manufactured by Sanshin Chemical Industry Co., Ltd.), Sun-Aid SI-100
L (manufactured by Sanshin Chemical Industry Co., Ltd.), CI-2064 (manufactured by Nippon Soda Co., Ltd.), CI-2639 (manufactured by Nippon Soda Co., Ltd.), CI-262
Commercially available compounds such as No. 4 (manufactured by Nippon Soda Co., Ltd.), CI-2481 (manufactured by Nippon Soda Co., Ltd.), and RHODORSIL PHOTOINITIATOR 2074 (manufactured by Rh ヌ ne-L ラ ン n) or a solution thereof can be used.

A plurality of the above-mentioned cationic photopolymerization initiators may be used in combination, and a photosensitizer, for example, a thioxanthone derivative compound may be used in an appropriate combination in order to promote the polymerization.

[Conductive Particles (D)] In the first aspect of the present invention, the conductive particles (D) are dispersed in the polymer (A) and the photocurable resin (B). in this case,
The mode of dispersion is not limited as long as anisotropic conductivity can be exhibited. Usually, since the anisotropic conductivity is exhibited by making the particle size of the conductive particles larger than the thickness of the sheet, in this case,
As long as the adjacent conductive particles do not directly contact, insulation can be ensured in the plane direction. The particle size may be appropriately selected according to the circuit pattern to be connected and the pitch.

As the conductive particles (D), for example,
Gold, silver, copper, nickel, palladium, platinum, cobalt,
Rhodium, iridium, iron, ruthenium, osmium,
A suitable metal such as aluminum, zinc, tin, lead, etc. in the form of particles; an alloy of the above metals in the form of particles; a metal oxide such as tin oxide in the form of particles; conductive carbon such as carbon Examples include, but are not particularly limited to, particles of an allotrope, insulating particles such as glass, carbon, mica, and plastic coated on a surface with a conductive metal. Further, two or more kinds of conductive particles may be used in combination.

The average particle size of the conductive particles is not particularly limited as described above, but is preferably in the range of 1 to 20 μm. If it is less than 1 μm, the cohesive force between the conductive particles becomes remarkable, and it may become difficult to uniformly disperse the conductive particles when producing an anisotropic conductive photo-curable pressure-sensitive adhesive sheet, and if it exceeds 20 μm, When the distance between the lines is reduced when joining a fine circuit, the possibility of causing a short circuit increases.

[Blending Ratio] The anisotropic conductive photo-curable pressure-sensitive adhesive sheet according to the present invention comprises the polymer (A), the photo-curable resin (B), the curing catalyst (C), and the conductive particles ( D) as an essential component.
It is appropriately selected according to the desired tackiness and curing characteristics. Preferably, the photocurable resin (B) is blended in an amount of 5 to 5,000 parts by weight based on 100 parts by weight of the polymer (A). When the compounding ratio of the photocurable resin is less than 5 parts by weight, the strength of the adhesive cured product is not sufficient, and it may be difficult to secure the bonding reliability after curing, and the amount may exceed 5000 parts by weight. This makes it difficult to control adhesiveness, and it may be difficult to achieve both sheet cohesive strength and adhesive strength.

The conductive particles (D) are preferably blended in an amount of 0.1 to 2,000 parts by weight based on 100 parts by weight of the polymer (A). When the compounding ratio of the conductive particles is less than 0.1 part by weight, the dispersion of the conductive particles in the anisotropic conductive photo-curing pressure-sensitive adhesive sheet becomes thin, and it may not be possible to secure conduction. If the amount exceeds the weight part, the transparency of the anisotropic conductive light post-curable pressure-sensitive adhesive sheet is impaired, and the transmittance of light used for the curing reaction may decrease,
It is difficult to completely cure. In addition, a short circuit occurs between adjacent wirings.

The mixing ratio of the curing catalyst (C) is selected depending on the type of the photocurable resin (B) and the curing mechanism.
The range is 0.001 to 100 parts by weight based on parts by weight. If the compounding ratio of the curing catalyst (C) is less than 0.001 part by weight, even if the curing catalyst is activated by irradiating light, the concentration of the cationic polymerization species does not become sufficiently high, and it is difficult to increase the curing speed. When it exceeds 100 parts by weight, the curing proceeds rapidly on the surface of the anisotropic conductive photo-curable pressure-sensitive adhesive sheet, and the electric component on the bonding surface of the anisotropic conductive light post-curable pressure-sensitive adhesive sheet Adhesion may decrease.

[Other Additives] The present invention is an anisotropically conductive photo-curable pressure-sensitive adhesive sheet characterized by containing the essential components described above. Accordingly, the following additives may be appropriately compounded.

For example, when an epoxy resin is used as the photocurable resin (B), a vinyl ether-based compound may be further added in order to lengthen the time from light irradiation to application, that is, the pot life. When a vinyl ether compound is contained, the compounding ratio is preferably in the range of 1 to 30 parts by weight based on 100 parts by weight of the epoxy resin. The mixing ratio of the vinyl ether compound is 1
If the amount is less than 10 parts by weight, it is difficult to sufficiently obtain the effect of extending the pot life. If the amount exceeds 30 parts by weight, the strength of the cured product after curing may be reduced, and sufficient adhesive strength may not be exhibited.

Further, an appropriate tackifying resin may be added in order to increase the tackiness. As the tackifying resin, a known appropriate tackifying resin such as a rosin resin, a modified rosin resin, a terpene resin, a terpene phenol resin, an aromatic modified terpene resin, a C5 or C9 petroleum resin, and a cumarone resin is used. be able to.

Further, in order to enhance the coating property, a thickening agent having electrical insulation properties, a thixotropic agent, a bulking agent and the like may be appropriately added. Examples of the thickener include acrylic rubber, epichlorohydrin rubber, isoprene rubber, and butyl rubber, and examples of the thixotropic agent include colloidal silica and polyvinylpyrrolidone.Examples of the extender include calcium carbonate, titanium oxide, and clay. And the like.

Further, in order to enhance the adhesive strength, inorganic hollow bodies such as electrically insulating glass balloons, alumina balloons, ceramic balloons, etc .; nylon beads, acrylic beads, silicon beads, acrylonitrile-butadiene copolymers may be used as reinforcing agents. Organic spheres such as particles, particles comprising terminal carboxylated acrylonitrile-butadiene copolymer (CTBN); organic hollow bodies such as vinylidene chloride balloons and acrylic balloons; simple materials such as glass, polyester, rayon, nylon, cellulose, etc. Fibers and the like may be added.

[Production Method] The method for producing the anisotropically conductive light post-curable pressure-sensitive adhesive sheet according to the present invention is not particularly limited, and may be a solvent casting method, an extrusion coating method, a calendering method, or a UV method.
A known method such as a coating polymerization method can be used.

For example, in the solvent casting method, the polymer (A), the photocurable resin (B) and the curing catalyst (C) are dissolved in a solvent, and the conductive particles (D) are further dispersed. By casting the solution on a release-treated film and drying the solvent, an anisotropic conductive photo-curable pressure-sensitive adhesive sheet can be obtained.

In the hot melt coating method, the polymer (A),
The photocurable resin (B) and the curing catalyst (C) may be mixed by heating, and a composition obtained by dispersing the conductive particles (D) may be subjected to hot melt coating.

The UV coating polymerization method can be used when an acrylic polymer is used as the polymer (A) and a cationic curable resin is used as the photocurable resin (B). That is, a monomer component containing an acrylic monomer for constituting the polymer (A), a photo-curable resin (B), a curing catalyst (C), and a monomer component for constituting the acrylic polymer are mixed with light. A photo-radical polymerization catalyst for radical polymerization is mixed, and the conductive particles (D) are dispersed and coated. The photo-radical polymerization initiator is activated without activating the curing catalyst (C), and acrylic Examples of the method include a method of obtaining a system polymer and forming an adhesive sheet. In this case, in order to uniformly disperse and stabilize the conductive particles, in addition to the acrylic polymer obtained by radical polymerization such as an acrylic polymer, another polymer is added to the compound before coating. May be.

Preferred embodiments of the UV coating polymerization method include:
Compound having an epoxy group, a cationic photopolymerization initiator,
(Meth) acrylate monomer, a photo-radical polymerization initiator sensitive to light in a wavelength region where the curing catalyst (C) is insensitive,
A photopolymerizable composition comprising the conductive particles (D) is used. This photopolymerizable composition is applied to an appropriate sheet substrate, only the photoradical polymerization initiator is exposed to light, radical polymerization is caused, and the coating film applied with the above material is used as a polymer (A). By forming an acrylic polymer, an anisotropic conductive photo-curable pressure-sensitive adhesive sheet can be obtained.

As the lamp used for light irradiation in the photoradical polymerization, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, a metal halide lamp, and the like are used. And is not particularly limited. In this case, when light in a wavelength range sensitive to the photocationic polymerization initiator is irradiated, light having such a wavelength may be cut off and irradiated by using an appropriate filter.

[Method of Joining Electric Parts] The method of joining electric parts according to the present invention joins electric parts using the anisotropic conductive photo-curable pressure-sensitive adhesive sheet according to the present invention. In this case, when one or both of the electrical components to be joined transmit light, after bonding the two electrical components with an anisotropic conductive photo-curing adhesive sheet,
Light may be irradiated from the transparent electric component side to start the curing reaction of the photocurable resin. After curing for a predetermined time at room temperature, the curing can be completed and joined.

When there is a concern that the electric parts may be damaged by the irradiation light, the anisotropic conductive light post-curing pressure-sensitive adhesive sheet is first irradiated with light, and then the anisotropic conductive light post-curing pressure-sensitive adhesive sheet is irradiated. It is preferable to use a method for electrically connecting and joining two electric components with each other.

Specifically, first, after irradiating the above-mentioned anisotropic conductive light post-curing type pressure-sensitive adhesive sheet with light to activate the curing reaction, the two electric parts are connected to each other while maintaining the adhesiveness. And bonding. Thereafter, curing is carried out at room temperature for a predetermined time to saturate the curing reaction and complete the joining.

Alternatively, an anisotropic conductive photo-curable pressure-sensitive adhesive sheet is bonded to one of the electrical components in advance, and then the surface layer of the anisotropic conductive photo-curable pressure-sensitive adhesive sheet is irradiated with light to activate the curing reaction. And the other electrical component is bonded and joined. Thereafter, predetermined curing is performed at room temperature to saturate the curing reaction and complete the bonding.

The light used for curing is selected according to the curing catalyst (C) to be used, and is not particularly limited. Preferably, light containing a component having a wavelength of 200 to 800 nm is used. When light having a wavelength of less than 200 nm is irradiated, only the surface layer of the anisotropically conductive light post-curable pressure-sensitive adhesive sheet is cured, does not exhibit adhesive strength at the time of bonding, and may not be able to join electric components. When light exceeding 800 nm is irradiated, it is difficult to apply sufficient energy to the curing catalyst (C), and it may be difficult to cure the anisotropic conductive photo-curable pressure-sensitive adhesive sheet. More preferably, the handling of the light source is easy, so
Light having a wavelength in the range of 0 nm is used.

The light source is not particularly limited as long as it can cure the photocurable resin (B). For example, examples of the ultraviolet or visible light source include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, a metal halide lamp, a fluorescent lamp, and sunlight. In order to prevent curing of only the surface layer and realize internal curing, it is preferable to cut and irradiate light of less than 200 nm. In the present specification, the electric component is not particularly limited as long as it constitutes an electric / electronic device.

(Use) The use of the anisotropically conductive light post-curing pressure-sensitive adhesive sheet of the present invention is not particularly limited as long as it is used for electric connection between electric and electronic parts constituting electric products and electronic products.

Examples of the electric and electronic products include mobile communication devices such as mobile phones, pagers, and mobile personal computers, information holding / recording cards such as IC cards, supercomputers, workstations, desktop computers, and notebook computers. Computers, various printers, magneto-optical disk drives, CD disk drives, computers such as scanners and their peripheral devices,
General home appliances such as cameras, tape video cassette recorders, video cameras, televisions, radios, DVDs, CD players, stationary telephones, videophones, and integrated stereo components can be mentioned.

The electric parts include electric products,
There is no particular limitation as long as it constitutes an electronic product, but since the time of the joining step can be reduced and the joining can be realized in a small space, at least one of the flexible printed circuit board and the rigid printed circuit board is used. The present invention can be suitably used in the case of a transparent electric wiring glass substrate, a transparent electric wiring resin substrate, and an integrated circuit module.

[Function] In the anisotropically conductive photo-curable pressure-sensitive adhesive sheet according to the first aspect of the present invention, the polymer (A) is blended so as to have tackiness in the initial state. It can be easily attached to electrical parts that are bodies. By irradiating light, the curing catalyst (C)
Is activated, and the photocurable resin (B) is cured. Therefore, curing is promoted by irradiating light before or after attaching the anisotropic conductive light post-curing pressure-sensitive adhesive sheet to an adherend such as an electric component. Therefore, for example, by bonding two electric components together with an anisotropic conductive photo-curing pressure-sensitive adhesive sheet, the electric components are firmly joined after the final curing.

Further, in the anisotropically conductive photo-curable pressure-sensitive adhesive sheet, since the conductive particles (D) are appropriately dispersed, the anisotropically conductive photo-curable adhesive sheet exhibits anisotropic conductivity. Accordingly, the joined electric components are reliably electrically connected to each other, and exhibit no conductivity in a direction other than the joining direction, so that a short circuit with another member can be prevented. In addition, the completion of the curing of the photocurable resin enhances the reliability of the electrical connection between the electric components.

In the invention according to claim 2, the polymer (A)
A (meth) acrylic polymer is used as the resin, a resin containing at least one cationically polymerizable group in one molecule is used as the photocurable resin (B), and a curing catalyst (C)
Since a photo-cationic polymerization initiator is used as the photo-polymerization initiator, it can be easily attached to an adherend due to the tackiness of the (meth) acrylic polymer in the initial state, and is irradiated with light for activating the photo-cationic polymerization initiator. Thus, a resin having at least one cationically polymerizable group in one molecule is cured by a cationic polymerization reaction. Therefore, similarly to the first aspect of the present invention, it can be suitably used, for example, for electrically connecting and joining electric components, and by completion of curing, the electrical connection utilizing anisotropic conductivity is completed. Can increase reliability.

According to the third aspect of the invention, since the resin having at least one cationically polymerizable group in one molecule is an epoxy resin, it exhibits excellent weather resistance, chemical resistance and heat resistance after completion of curing. .

In the invention according to claim 4, the polymer (A)
5 to 500 parts by weight of the photocurable resin (B) based on 100 parts by weight
0 parts by weight, and the conductive particles (D) are mixed in a ratio of 0.1 to 2000 parts by weight.
Excellent balance between cohesive strength and adhesive strength of the sheet in the initial state, and having sufficient strength when the curing of the photo-curable resin is completed, thus achieving a highly reliable anisotropic conductive connection. Can be.

According to a fifth aspect of the present invention, there is provided a method for bonding an electric component, wherein the anisotropic conductive photo-curable pressure-sensitive adhesive sheet according to any one of the first to fourth aspects is used to electrically connect the two electric components. At the time of connection, the anisotropic conductive light post-curing adhesive sheet is irradiated with light, so that the two electrical components can be easily bonded together at first using the adhesiveness, and the curing that proceeds after light irradiation Upon completion of the reaction, eventually
The electric components are securely joined together, and both are electrically connected with high reliability.

In the invention according to claim 6, since light containing a component having a wavelength of 200 to 800 nm is used as the light, it is possible to provide sufficient energy to complete the curing reaction in a relatively short time, The curing can be completed in a relatively short time, the curing of only the surface layer of the anisotropically conductive photo-curable pressure-sensitive adhesive sheet can be suppressed, and the electric components can be easily bonded to each other.

[0082]

The present invention will be clarified by the following non-limiting examples.

Example 1 In a 2 L separable flask, a copolymer of ethyl acrylate (EA) and glycidyl methacrylate (GMA) (weight average molecular weight 700,000, composition ratio: EA / GMA) as polymer (A) = 8/2
(Weight ratio)) 100 g, an epoxy resin (product name: Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd.) as a photocurable resin (B), and a photocationic polymerization initiator (Asahi Denka Kogyo Co., Ltd.) as a curing catalyst (C) (Trade name: Optmer SP-170, trade name: 1.0 g), and 40 g of nickel powder (average particle size: 15 μm) as conductive particles (D) were mixed with ethyl acetate 3.
The mixture was stirred and dissolved until it became uniform at 00 g to obtain a coating composition.

The coating composition thus obtained was
A polyethylene terephthalate film whose surface was release-treated was coated so that the thickness after drying was 20 μm, to obtain an anisotropic conductive photo-curable pressure-sensitive adhesive sheet.

(Examples 2 to 8) The composition of the coating composition was
An anisotropic conductive photo-curable pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive sheet was changed as shown in Table 1 below.

(Example 9) In a 0.5 L separable flask, 50 g of glycidyl methacrylate, 50 g of an epoxy resin (trade name: Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd.) as a photocurable resin (B), and 400 nm
Bis (2,2)
0.10 g of 6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide (manufactured by Ciba Geigy, trade name: Irgacure 1700) and photocationic polymerization initiation which is not sensitive to light of 400 nm as a curing catalyst (C) Agent (Asahi Denka Kogyo Co., Ltd., trade name: Optomer SP)
-170) 0.5 g and 20 g of nickel powder (average particle size: 15 μm) as conductive particles (D) were stirred and mixed until uniform, and then dissolved oxygen was removed by bubbling with nitrogen gas for 20 minutes. Thus, a photopolymerizable composition was obtained.

Two sets of laminates in which a PET film subjected to a release treatment was adhered to a glass plate were prepared.
With the film on the inside, the photopolymerizable composition is sandwiched via a spacer so as to have a thickness of 20 μm,
A laminate in which the photopolymerizable composition was disposed at the center in the thickness direction was obtained. This laminate was irradiated with light for 10 minutes using a fluorescent lamp having a maximum emission wavelength at 400 nm so that the light intensity became 1 mW / cm ^2, and photopolymerized glycidyl methacrylate to produce a polymer (A). Thus, an anisotropic conductive light post-curing pressure-sensitive adhesive sheet was obtained.

Examples 10 and 11 Except that the composition of the photopolymerizable composition was changed as shown in Table 2 below,
In the same manner as in Example 9, an anisotropic conductive photo-curable pressure-sensitive adhesive sheet was obtained.

(Comparative Example 1) Without using the curing catalyst (C),
A composition obtained in the same manner as in Example 1 was used except that 1 part by weight of dicyandiamide (DICY) was blended as a thermosetting catalyst. I got a sheet.

Comparative Examples 2 to 5 Anisotropically conductive thermosetting adhesive was prepared in the same manner as in Comparative Example 1 except that the composition of the composition was changed as shown in Tables 1 and 2 below. I got a sheet.

(Evaluation) The anisotropically conductive photocurable pressure-sensitive adhesive sheets obtained in Examples 1 to 11 and the anisotropically conductive thermosetting pressure-sensitive adhesive sheets obtained in Comparative Examples 1 to 5 were adhered in the following manner. The force, connection resistance, and stability over time were evaluated.

Adhesive Strength A flexible printed wiring board (FPC) having a copper wiring pattern formed on a polyimide film having a thickness of 50 μm at a pitch of 200 μm and ITO glass having a thickness of 1 mm (surface resistance: 20 Ω) were joined. That is, FPC
After laminating an anisotropic conductive photo-curable pressure-sensitive adhesive sheet on the wiring surface of above, and irradiating the surface of the anisotropic conductive photo-curable pressure-sensitive adhesive sheet with ultraviolet rays at 25 mW / cm ² for 30 seconds using a high-pressure mercury lamp, PET Peel the film and apply ITO glass to 30k
Crimping was performed under a pressure of gf / cm ² to obtain a joined body. This conjugate was cured at a temperature of 25 ° C. for 7 days from ultraviolet irradiation.

The adhesion was evaluated by measuring the FPC with a width of 10 mm.
Was peeled at 180 ° C. at a peeling speed of 50 mm / min. The strength in this case was measured and defined as the adhesive strength. Comparative Example 1
In Nos. 5 to 5, when bonding the FPC and the ITO glass, an anisotropic conductive thermosetting adhesive sheet was laminated on the wiring surface of the FPC, and then the ITO glass was filled with 30 kgf.
/ Cm ² was applied under pressure to form a bonded body, which was then cured at a temperature of 25 ° C. for 7 days to obtain a sample used for evaluation of adhesive strength. About this sample, Examples 1-11
As in the case of the above, the adhesive strength was evaluated.

Connection Resistance As shown in FIGS. 1 (a) and 1 (b), a flexible printed circuit board (FPC) in which connection portions of copper wirings 1 and 1 are formed on one surface in parallel with each other at a pitch of 200 μm. 2) were prepared, and the surfaces of the FPCs 2 and 2 on which the wiring patterns were formed were opposed to each other, and were bonded together using the anisotropic conductive photo-curing adhesive sheet 3. Note that the copper wiring 1 indicated by a broken line indicates that it is formed on the lower surface. In this case, the resistance a between the ends of the joined body obtained by bonding, that is, the joining of the copper wiring pattern on the other FPC2 to the end opposite to the joining part of the copper wiring pattern on one FPC. The resistance value between the portion and the opposite end and the resistance value b between adjacent wiring patterns were measured.

Further, as for the joined body used in the above-mentioned evaluation of the adhesive strength, as shown in FIG. 2, the resistance value c between the end of the FPC wiring pattern opposite to the joined part and the ITO glass d was measured. did.

Stability over time The FPC and 1 mm thick ITO glass (surface resistance: 20 Ω) bonded by an anisotropic conductive photo-curable pressure-sensitive adhesive sheet by the above method were cured for 7 days at 40 ° C. in an atmosphere. rear,
The resistance value c was measured.

The results are shown in Tables 1 and 2 below. The details of the polymers A-1 and A-2 in Table 1 are as follows. Polymer A-1: Ethyl acrylate (EA) / glycidyl methacrylate (GMA) copolymer (weight average molecular weight 700,000, composition ratio: EA / GMA = 8/2 (weight ratio)) Polymer A-2: t- Butyl acrylate (TBA) / tetrahydrofurfuryl acrylate (THFA) copolymer (weight average molecular weight 700,000, composition ratio: TBA / THFA
= 9/1 (weight ratio)

[0098]

[Table 1]

[0099]

[Table 2]

As is clear from the comparison between the results of Comparative Examples 1 to 5 and the results of Examples 1 to 11, the anisotropic conductive photo-curing pressure-sensitive adhesive sheets of Examples 1 to 11 It can be seen that it exhibits the same adhesive strength and connection resistance as the anisotropic conductive thermosetting pressure-sensitive adhesive sheet of No. 5.

However, the thermosetting pressure-sensitive adhesive sheets of Comparative Examples 1 to 5 do not adhere and cure at 25 ° C., so that it may be difficult to establish a conductive connection over time. Therefore, Examples 1 to
According to No. 11, the electric components can be firmly joined to each other without causing the deterioration of the adherend by heat, and the electric components can be securely connected by utilizing the anisotropic conductivity without causing deterioration with time. It can be seen that the connection can be made.

[0102]

The anisotropic conductive photo-curable pressure-sensitive adhesive sheet according to the present invention is constituted so as to have tackiness by the polymer (A), so that it can be easily attached to an adherend such as an electric component. can do. Further, the irradiation of light activates the curing catalyst (C), and the curing reaction in the photocurable resin (B) proceeds to cure. Therefore, the reliability of the electrical connection between the adherends by the conductive particles (D) is enhanced, and the adherends are firmly joined. Therefore,
By using the anisotropically conductive photo-curable pressure-sensitive adhesive sheet according to the present invention, for example, flexible printed wiring boards can be easily joined to each other or other electrical components, and the reliability of the anisotropically conductive connection can be improved. It is possible to increase. In addition, since heat is not required for curing, it can be suitably used for connection of an electric component using a material having poor heat resistance or an electric component made of a material having insufficient thermal dimensional stability.

In the method for joining electric parts according to the present invention,
In joining and electrically connecting two electrical components,
The anisotropic conductive light post-curable pressure-sensitive adhesive sheet according to the present invention is irradiated with light, and the two are bonded using the anisotropic conductive light post-curable pressure-sensitive adhesive sheet. The two electric components can be easily joined together by utilizing the adhesiveness of the curable adhesive sheet. In addition, after the light irradiation, the curing reaction of the photocurable resin proceeds, so that after the curing reaction is completed, the two electric components are firmly joined together,
The reliability of the anisotropic conductive connection via the conductive particles (D) is improved. In addition, since heat is not required for the curing reaction, it can be suitably used for connection of electric parts using a material having poor heat resistance or a material having poor thermal dimensional stability.

[Brief description of the drawings]

FIG. 1 is a plan view and a side view for explaining a joined body of an FPC and an ITO glass plate used in evaluating the adhesive strength of a curable pressure-sensitive adhesive sheet of an example and a comparative example.

FIG. 2 is a plan view and a side view for explaining a joined body sample used for evaluating the adhesive strength of the curable pressure-sensitive adhesive sheets of Examples and Comparative Examples.

[Explanation of symbols]

 3: Anisotropic conductive light post-curing adhesive sheet

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01R 4/04 H01R 4/04

Claims (6)

[Claims] 1. A polymer (A) and a photocurable resin (B)
And a curing catalyst (C) for curing the photocurable resin;
An anisotropically conductive photo-curable pressure-sensitive adhesive sheet comprising conductive particles (D) and having tackiness. 2. The method according to claim 1, wherein the polymer (A) is a (meth) acrylic polymer, the photocurable resin (B) is a resin having at least one cationically polymerizable group in one molecule, The anisotropically conductive photo-curable pressure-sensitive adhesive sheet according to claim 1, wherein the catalyst (C) is a photocationic polymerization initiator. 3. The resin having at least one cationically polymerizable group in one molecule is an epoxy resin.
The anisotropic conductive photo-curable pressure-sensitive adhesive sheet according to item 1. 4. The polymer (A) based on 100 parts by weight,
The photocurable resin (B) is blended in an amount of 5 to 5000 parts by weight and the conductive particles (D) in an amount of 0.1 to 2000 parts by weight. The anisotropic conductive photo-curable pressure-sensitive adhesive sheet according to item 1. 5. An anisotropically conductive photo-curable pressure-sensitive adhesive for electrically connecting two electrical components using the anisotropically conductive photo-curable pressure-sensitive adhesive sheet according to claim 1. A method for joining electric parts, comprising irradiating a sheet with light. 6. The method according to claim 5, wherein light having a wavelength of 200 to 800 nm is used as the light.