JP6470944B2 - Conductive adhesive composition and conductive adhesive sheet - Google Patents

Description

  The present invention relates to a conductive pressure-sensitive adhesive composition and a conductive pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed from the conductive pressure-sensitive adhesive composition.

Conventionally, when producing electrical parts, electronic parts, semiconductor parts, etc., an adhesive sheet may be used for the purpose of temporarily fixing the parts or protecting a circuit or the like.
The pressure-sensitive adhesive sheet used for such applications is required to have a strong adhesive force (peeling resistance) in the treatment process after sticking, but is peeled off after completion of the predetermined treatment process. Re-peelability that can be peeled off with a small force without contaminating the body is required. Moreover, when peeling these adhesive sheets, static electricity called peeling electrification is easy to occur between adherends such as parts and circuits and the adhesive sheet. Due to the generation of static electricity, parts and circuits that are adherends may be destroyed.

In order to suppress the generation of static electricity at the time of peeling of the pressure-sensitive adhesive sheet, means for improving the conductivity of the pressure-sensitive adhesive layer by dispersing a conductive substance such as metal powder or carbon-based filler in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet Are known.
As an adhesive sheet having such an adhesive layer, for example, Patent Document 1 discloses an adhesive sheet having an adhesive layer made of an adhesive composition containing a carbon nanomaterial and a conductive polymer together with an adhesive. Yes.
Patent Document 2 discloses a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive composition in which a carbon nanomaterial is dispersed in a pressure-sensitive adhesive with a polyether-based dispersant.
In Patent Documents 1 and 2, a monomer and / or oligomer having an energy ray polymerizable group, a photopolymerization initiator, and the like are further blended in the pressure-sensitive adhesive composition, so that energy rays such as ultraviolet rays can be contained. There is also a statement that the adhesive sheet can be easily peeled off from the adherend by reducing the adhesive strength by irradiation.

JP 2010-163586 A JP 2010-163587 A

However, the pressure-sensitive adhesive sheets disclosed in Patent Documents 1 and 2 have room for further improvement from the viewpoint of improving the effect of suppressing the generation of static electricity during peeling.
In order to improve the conductivity of the pressure-sensitive adhesive sheet, a means of increasing the blending amount of the conductive substance in the pressure-sensitive adhesive layer may be considered, but increasing the blending amount of the conductive substance in the pressure-sensitive adhesive layer reduces the adhesive strength. Result.

  The present invention provides a conductive pressure-sensitive adhesive composition which is a material for forming a pressure-sensitive adhesive layer having excellent antistatic properties and conductivity, which has good adhesive strength and removability and can suppress the generation of static electricity during peeling. And it aims at providing the electroconductive adhesive sheet using the said electroconductive adhesive composition.

The inventors of the present invention provide a conductive pressure-sensitive adhesive composition containing a polymerizable compound having a mass average molecular weight of a specific value or less and a predetermined amount of a carbon-based filler with respect to a pressure-sensitive adhesive resin containing an acrylic resin. The inventors have found that this can be solved and completed the present invention.
That is, the present invention provides the following [1] to [14].
[1] An adhesive resin (A) containing an acrylic resin (A1), a polymerizable compound (B) having a mass average molecular weight (Mw) of 5000 or less and having an energy ray polymerizable group, and a carbon filler (C )
The electroconductive adhesive composition whose content of a carbon-type filler (C) is 0.1-7.0 mass parts with respect to a total of 100 mass parts of a component (A) and (B).
[2] In the above [1], the content of the non-adhesive compound (β) having a mass average molecular weight (Mw) exceeding 5000 is 5% by mass or less based on the total amount of the conductive adhesive composition. The electroconductive adhesive composition of description.
[3] A non-adhesive compound (β), a polymerizable compound (β1) having an energy ray polymerizable group having a mass average molecular weight (Mw) exceeding 5000, and a conductive polymer having a mass average molecular weight (Mw) exceeding 5000 The conductive adhesive composition according to the above [2], which is at least one selected from (β2) and a polyether dispersant (β3) having a mass average molecular weight (Mw) of more than 5,000.
[4] The conductive adhesive composition according to any one of [1] to [3], wherein the polymerizable compound (B) includes a polyfunctional urethane acrylate oligomer.
[5] The conductive pressure-sensitive adhesive composition according to any one of [1] to [4], wherein the number of groups in one molecule of the energy beam polymerizable group of the polymerizable compound (B) is 4 to 10. object.
[6] The conductive material according to any one of [1] to [5], wherein the content of the polymerizable compound (B) is 10 to 150 parts by mass with respect to 100 parts by mass of the component (A). Adhesive composition.
[7] The conductive adhesive composition according to any one of [1] to [6] above, wherein the acid value of the adhesive resin (A) is 20 mg KOH / g or less.
[8] Any of the above [1] to [7], wherein the content of the structural unit derived from (meth) acrylic acid is 5% by mass or less based on the total amount of the structural unit of the acrylic resin (A1). 2. The conductive adhesive composition according to item 1.
[9] The conductive adhesive composition according to any one of the above [1] to [8], wherein the average aspect ratio of the carbon-based filler (C) is 5 or more.
[10] The conductive pressure-sensitive adhesive composition according to any one of [1] to [9], wherein the carbon-based filler (C) includes a carbon nanomaterial.
[11] A conductive pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed from the conductive pressure-sensitive adhesive composition according to any one of [1] to [10].
[12] The surface resistivity after energy ray irradiation of the pressure-sensitive adhesive layer (ρ _S2), wherein the ratio of the surface resistivity before the energy ray irradiation of the pressure-sensitive adhesive layer ([rho _S1) [ρ _{S2 /} ρ _S1] is The conductive adhesive sheet according to [11], which is 9.0 × 10 ⁻² or less.
[13] The conductive pressure-sensitive adhesive sheet according to [11] or [12], which is used for conveying an insulating material.
[14] The conductive pressure-sensitive adhesive sheet according to [11] or [12], which is used for transporting a conductive material.

  The conductive pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed from the conductive pressure-sensitive adhesive composition of the present invention has excellent adhesion and removability, and excellent antistatic properties that can suppress the generation of static electricity during peeling. And conductivity.

It is sectional drawing of the said conductive adhesive sheet which shows an example of a structure of the conductive adhesive sheet of 1 aspect of this invention.

In the present specification, “mass average molecular weight (Mw)” is a value in terms of standard polystyrene measured by gel permeation chromatography (GPC), and specifically measured based on the method described in Examples. It is the value.
For example, “(meth) acrylate” is used as a term indicating both “acrylate” and “methacrylate”, and the same applies to other similar terms.
In the following description of the present specification, the “surface resistivity of the conductive adhesive sheet” means that the adhesive surface of the adhesive layer of the conductive adhesive sheet is exposed unless otherwise specified. The surface resistivity measured from the surface side is meant, and a specific measuring method is as described in the examples.

[Conductive adhesive composition]
The conductive pressure-sensitive adhesive composition of the present invention comprises a pressure-sensitive adhesive resin (A) containing an acrylic resin (A1), a weight average molecular weight (Mw) of 5000 or less, and a polymerizable compound (B ) (Hereinafter also simply referred to as “polymerizable compound (B)”) and carbon-based filler (C).

The conductive pressure-sensitive adhesive composition of the present invention contains the above-described polymerizable compound (B) together with the pressure-sensitive resin (A) containing the acrylic resin (A1) and the carbon-based filler (C). The pressure-sensitive adhesive layer formed from the adhesive composition can be cured by irradiation with energy rays, the adhesive strength can be reduced, the surface resistivity can be reduced, and the generation of static electricity during peeling can be suppressed.
This is because the formed pressure-sensitive adhesive layer has a polymer formed by polymerizing components (B) in the polymer network of component (A1), and forms the so-called semi-IPN structure. It is thought to be expressed.

Note that the conductive pressure-sensitive adhesive composition of one embodiment of the present invention is a high-molecular-weight non-tacky compound (for example, a high-molecular weight polymerizable compound, a high-molecular conductor, or a polyether) that can cause contamination of an adherend. It is not necessary to contain a dispersant or the like.
In addition, the conductive adhesive composition of one embodiment of the present invention can reduce the surface resistivity of the formed adhesive layer even when the content of the carbon-based filler (C) is reduced. Since it is not necessary to contain the carbon filler (C), it has good adhesiveness.

The conductive pressure-sensitive adhesive composition of one embodiment of the present invention preferably further contains a photopolymerization initiator (D), and may further contain a crosslinking agent (E). You may contain general purpose additives, such as a tackifier, in the range which does not impair an effect.
Hereinafter, each component contained in the electroconductive adhesive composition of this invention is demonstrated.

<Adhesive resin (A)>
In the present invention, “adhesive resin” means a resin having adhesiveness by itself and having a mass average molecular weight (Mw) of 10,000 or more.
The mass average molecular weight (Mw) of the adhesive resin (A) is preferably 10,000 to 2,000,000, more preferably 20,000 to 1,500,000, still more preferably 30,000 to 1,000,000.

Although the conductive adhesive composition of this invention contains acrylic resin (A1) as adhesive resin (A), you may also contain other adhesive resins other than acrylic resin (A1).
Examples of other adhesive resins include urethane resins, polyisobutylene resins, polyester resins, polyolefin resins, and modified resins thereof.
These other adhesive resins may be used alone or in combination of two or more.

In one embodiment of the present invention, the acid value of the adhesive resin (A) is preferably 20 mgKOH / g or less, more preferably 15 mgKOH / g or less, still more preferably 10 mgKOH / g or less, and even more preferably 5 mgKOH / g or less. is there.
When the acid value of the adhesive resin (A) is 20 mgKOH / g or less, the adhesive layer formed from the obtained conductive adhesive composition can suppress outgas generated by the decomposition of the resin component. Moreover, the phenomenon which a to-be-adhered body corrodes can be suppressed.
In the present invention, the acid value of the adhesive resin means a value measured according to JIS K0070.

  In one embodiment of the present invention, the content of the acrylic resin (A1) with respect to the total amount (100% by mass) of the adhesive resin (A) is preferably 40 to 100% by mass, more preferably 55 to 100% by mass, More preferably, it is 70-100 mass%, More preferably, it is 85-100 mass%.

  Content of the adhesive resin (A) in the electroconductive adhesive composition of 1 aspect of this invention is with respect to the whole quantity (100 mass%) of the active ingredient (solid content) in the said electroconductive adhesive composition. The amount is preferably 30 to 95% by mass, more preferably 35 to 90% by mass, still more preferably 40 to 85% by mass, and still more preferably 45 to 80% by mass.

<Acrylic resin (A1)>
The acrylic resin (A1) used in the present invention is derived from, for example, a polymer containing a structural unit derived from an alkyl (meth) acrylate having a linear or branched alkyl group, or a (meth) acrylate having a cyclic structure. And a polymer containing the structural unit.
Further, when these polymers are copolymers, the form of copolymerization is not particularly limited, and examples of the acrylic copolymer include block copolymers, random copolymers, and graft copolymers. Either may be sufficient.

  The mass average molecular weight (Mw) of the acrylic resin (A1) is preferably 100,000 to 1,500,000, more preferably 200,000 to 1,300,000, still more preferably 300,000 to 1,100,000, still more preferably 350,000 to 90. Ten thousand.

In addition, the acrylic resin (A1) used in the present invention improves cohesion by reacting with the crosslinking agent in the case of blending a crosslinking agent as an additive from the viewpoint of improving the adhesiveness by adjusting the polarity. From the viewpoint of making it, a polymer containing a structural unit derived from a functional group-containing monomer is preferable.
Examples of the functional group include a hydroxy group, a carboxy group, an epoxy group, an amino group, a cyano group, a keto group, and an alkoxysilyl group. A hydroxy group, a carboxy group, or an epoxy group is preferable, and a hydroxy group is more preferable. .
The content of the structural unit derived from the monomer having a functional group with respect to the total amount (100% by mass) of the structural unit of the acrylic resin (A1) is preferably 0.1 to 50.0% by mass, more preferably 0. 0.5-35.0% by mass, more preferably 0.7-25.0% by mass, and still more preferably 1.0-15.0% by mass.

  The acid value of the acrylic resin (A1) used in one embodiment of the present invention is preferably 20 mgKOH from the viewpoint of suppressing the phenomenon that the adherend is corroded by the pressure-sensitive adhesive layer formed from the obtained conductive pressure-sensitive adhesive composition. / G or less, more preferably 15 mgKOH / g or less, still more preferably 10 mgKOH / g or less, still more preferably 5 mgKOH / g or less.

  Further, from the viewpoint of adjusting the acid value of the acrylic resin (A1) to the above range, the content of the structural unit derived from the carboxyl group-containing monomer with respect to the total amount (100% by mass) of the structural unit of the acrylic resin (A1). The amount is preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less, and still more preferably 0.1% by mass or less.

The specific acrylic resin (A1) used in one embodiment of the present invention is an alkyl (meth) acrylate (a1 ′) having an alkyl group having 1 to 20 carbon atoms (hereinafter also referred to as “monomer (a1 ′)”). ) And a functional unit-containing monomer (a2 ′) (hereinafter, also referred to as “monomer (a2 ′)”), an acrylic copolymer (A1- 1) is preferred.
The acrylic copolymer (A1-1) may contain a structural unit (a3) derived from another monomer (a3 ′) other than the monomers (a1 ′) and (a2 ′).
The above monomers (a1 ′) to (a3 ′) may be used alone or in combination of two or more.

As carbon number of the alkyl group which a monomer (a1 ') has, from a viewpoint of the improvement of an adhesive characteristic, Preferably it is 1-12, More preferably, it is 1-8, More preferably, it is 4-6.
Examples of the monomer (a1 ′) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and tridecyl ( Examples include meth) acrylate and stearyl (meth) acrylate.
Among these monomers (a1 ′), butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable, and butyl (meth) acrylate is more preferable.

  The content of the structural unit (a1) is preferably 50.0 to 99.9% by mass, more preferably 60.% with respect to the total structural unit (100% by mass) of the acrylic copolymer (A1-1). It is 0-99.5 mass%, More preferably, it is 70.0-99.0 mass%, More preferably, it is 80.0-98.5 mass%.

Examples of the monomer (a2 ′) include a hydroxy group-containing monomer, a carboxy group-containing monomer, an epoxy group-containing monomer, an amino group-containing monomer, a cyano group-containing monomer, a keto group-containing monomer, and an alkoxysilyl group-containing monomer. .
It is preferable that the functional group which a monomer (a2 ') has is a thing which can react with the energy-beam polymeric group which a polymeric compound (B) has. Therefore, the monomer (a2 ′) is appropriately selected according to the type of the polymerizable compound (B).
Among these monomers (a2 ′), one or more selected from hydroxy group-containing monomers, carboxy group-containing monomers, and epoxy group-containing monomers are preferable, and hydroxy group-containing monomers are more preferable.

Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl ( Examples thereof include hydroxyalkyl (meth) acrylates such as (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and glycerin di (meth) acrylate.
Examples of the carboxy group-containing monomer include (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid and the like.
Examples of the epoxy group-containing unsaturated monomer include glycidyl (meth) acrylate.

  The content of the structural unit (a2) is preferably 0.1 to 50.0% by weight, more preferably 0.8%, based on all the structural units (100% by weight) of the acrylic copolymer (A1-1). It is 5-35.0 mass%, More preferably, it is 0.7-25.0 mass%, More preferably, it is 1.0-15.0 mass%.

  In addition, as mentioned above, from the viewpoint of suppressing the phenomenon that the adherend due to the pressure-sensitive adhesive layer formed from the obtained conductive pressure-sensitive adhesive composition corrodes, the structural unit of the acrylic copolymer (A1-1) has The content of the structural unit derived from (meth) acrylic acid with respect to the total amount (100% by mass) is preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less, and still more preferably 0. .1% by mass or less.

  Examples of the monomer (a3 ′) include cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentenyloxyethyl. (Meth) acrylates having a cyclic structure such as (meth) acrylate and imide (meth) acrylate; olefins such as ethylene, propylene and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; butadiene, isoprene and chloroprene Diene monomers: styrene, α-methylstyrene, vinyl toluene, vinyl formate, vinyl acetate, (meth) acrylamide, (meth) acrylonitrile, (meth) acryloylmorpholine, N-vinyl Pyrrolidone, and the like.

  The content of the structural unit (a3) is preferably 0 to 40% by weight, more preferably 0 to 30% by weight, based on all the structural units (100% by weight) of the acrylic copolymer (A1-1). More preferably, it is 0-20 mass%, More preferably, it is 0-10 mass%.

<Polymerizable compound (B)>
The polymerizable compound (B) used in the present invention is a polymerizable compound having a mass average molecular weight (Mw) of 5000 or less and having an energy ray polymerizable group.
In the present invention, examples of the “energy beam” include ultraviolet rays, electron beams, α rays, β rays, γ rays and the like, and ultraviolet rays are preferable.
The “energy beam polymerizable group” is a group that can form a polymer by polymerizing the components (B) by irradiation of the energy beam, specifically, a vinyl group, (meth) Examples thereof include a polymerizable group containing a carbon-carbon double bond such as an acryloyl group and a vinyl ether group; a polymerizable group having a cyclic ether structure such as an epoxy group and an oxetanyl group;
In the polymerizable compound (B) used in the present invention, the energy beam polymerizable group may be present in either the main chain or the side chain of the polymerizable compound.

The weight average molecular weight (Mw) of the polymerizable compound (B) used in the present invention is 5000 or less, preferably 4500 or less, more preferably 4000 or less, still more preferably 3500 or less, and still more preferably 3000 or less.
When the Mw of the polymerizable compound (B) is more than 5000, the surface resistivity after irradiation of energy rays of the pressure-sensitive adhesive layer formed from the obtained conductive pressure-sensitive adhesive composition cannot be sufficiently reduced, The effect of suppressing the generation of static electricity at the time of peeling of the conductive pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer is poor. Further, even after irradiation with energy rays, the adhesive strength is not sufficiently lowered, and the removability tends to be inferior.
In addition, the adherend may be contaminated and the adhesive properties before energy beam irradiation tend to be reduced.
The mass average molecular weight (Mw) of the polymerizable compound (B) used in one embodiment of the present invention is preferably 200 or more, more preferably 500 or more, and still more preferably from the viewpoint of preventing contamination of the adherend. 1000 or more.

The number of groups in one molecule of the energy ray polymerizable group of the polymerizable compound (B) used in one embodiment of the present invention is preferably 4 to 10, more preferably 5 to 9, still more preferably 5 to 8, and more. More preferably, it is 5-7.
When the number of energy ray polymerizable groups is within the above range, the surface resistivity after irradiation of energy rays of the pressure-sensitive adhesive layer formed from the obtained conductive pressure-sensitive adhesive composition can be effectively reduced. As a result, the electroconductive pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer can effectively suppress the generation of static electricity during peeling.

Examples of the polymerizable compound (B) used in one embodiment of the present invention include a polyfunctional acrylate monomer or oligomer, a polyfunctional urethane acrylate oligomer, a polyfunctional polyester acrylate oligomer, and the like.
In one embodiment of the present invention, these polymerizable compounds (B) may be used alone or in combination of two or more.
Among these, from the viewpoint of forming a conductive pressure-sensitive adhesive composition as a material for forming a pressure-sensitive adhesive layer that can effectively reduce the surface resistivity after irradiation with energy rays, the polymerizable compound (B) includes urethane acrylate. It is preferable that a system oligomer is included.
In one embodiment of the present invention, the content of the urethane acrylate oligomer with respect to the total amount (100% by mass) of the polymerizable compound (B) is preferably 60 to 100% by mass, more preferably 70 to 100% by mass, and still more preferably. Is 80 to 100% by mass, more preferably 90 to 100% by mass.

  Examples of the multifunctional acrylate monomer or oligomer include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, hexanediol di ( (Meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol Hexa (meth) acrylate, glycerol tri (meth) acrylate, triallyl (meth) acrylate, bisphenol A ethylene oxide Sex di (meth) acrylate.

Examples of the urethane acrylate oligomer include a reaction product obtained by esterifying a hydroxyl group of a polyurethane pre-oligomer obtained from polyether polyol or polyester polyol and polyisocyanate with (meth) acrylic acid; polyether polyol or Examples thereof include a reaction product obtained by reacting a hydroxyl group-containing (meth) acrylate with a terminal isocyanate polyurethane oligomer obtained by a reaction between a polyester polyol and a polyisocyanate.
Examples of the polyisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4-diisocyanate, and the like. Can be mentioned.
Moreover, as said hydroxyl group containing (meth) acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, etc. are mentioned, for example.

  As the polyester acrylate oligomer, for example, a reaction obtained by esterification with (meth) acrylic acid to the hydroxyl group of a polyester pre-oligomer having a hydroxyl group at both ends, which is a condensate of a polyvalent carboxylic acid and a polyhydric alcohol. A reaction product obtained by esterifying a hydroxyl group at the terminal of an oligomer obtained by adding an alkylene oxide to a polyvalent carboxylic acid with (meth) acrylic acid; and the like.

  In one embodiment of the present invention, the content of the polymerizable compound (B) with respect to the total amount (100 parts by mass) of the adhesive resin (A) can effectively reduce the surface resistivity after irradiation with energy rays. From the viewpoint of forming a conductive pressure-sensitive adhesive composition as a material for forming the agent layer, preferably 10 to 150 parts by mass, more preferably 20 to 130 parts by mass, still more preferably 30 to 110 parts by mass, and still more preferably 50 to 50 parts by mass. 95 parts by mass.

  Moreover, in one aspect of the present invention, the content of the polymerizable compound (B) with respect to the total amount (100% by mass) of the active ingredient (solid content) in the conductive pressure-sensitive adhesive composition is from the same viewpoint as described above. Preferably it is 5-80 mass%, More preferably, it is 10-70 mass%, More preferably, it is 20-65 mass%, More preferably, it is 30-60 mass%.

<Carbon filler (C)>
Examples of the carbon-based filler (C) used in the present invention include conductive fillers containing carbon atoms, and specific examples include carbon nanomaterials, carbon black, milled carbon fibers, and graphite.
Among these, from the viewpoint of reducing the surface resistivity of the pressure-sensitive adhesive layer to be formed and improving the pressure-sensitive adhesive strength of the pressure-sensitive adhesive layer, the carbon-based filler (C) preferably contains a carbon nanomaterial. .
In one embodiment of the present invention, the content of the carbon nanomaterial with respect to the total amount (100% by mass) of the carbon-based filler (C) is preferably 50 to 100% by mass, more preferably 65 to 100% by mass, and still more preferably. It is 80-100 mass%, More preferably, it is 90-100 mass%.

Examples of the carbon nanomaterial include carbon nanotube (CNT), carbon nanofiber, carbon nanohorn, carbon nanocone, fullerene, and the like, and carbon nanotube is preferable.
The carbon nanotube is a cylindrical carbon polyhedron having a structure in which a graphite (graphite) sheet mainly having a carbon 6-membered ring structure is closed in a cylindrical shape.
The carbon nanotube includes a single-walled carbon nanotube having a structure in which a single-layer graphite sheet is closed in a cylindrical shape, a double-walled carbon nanotube having a structure in which a two-layer graphite sheet is closed in a cylindrical shape, and a three-layered graphite sheet There are multi-walled carbon nanotubes having a multi-layer structure closed concentrically as described above, and any two or more of these can be used in combination.

  Although there is no restriction | limiting in particular as a shape of a carbon-type filler (C), Column shape, cylinder shape, weight shape, fiber shape, and the shape which combined these are preferable, column shape, cylinder shape, fiber shape, and these were combined. The shape is more preferable.

  The average aspect ratio of the carbon-based filler (C) is preferably 5 or more, more preferably 10 to 10000, more preferably 50 to 1000, still more preferably 100 to 700, and still more preferably 130 to 400.

In the present specification, the “aspect ratio of the carbon-based filler (C)” is the ratio of the length (H) of the long side to the length (L) of the short side of the target carbon-based filler (C). That is, it is a value calculated from “long side length (H) / short side length (L)”. The “average aspect ratio” is an average value of the “aspect ratio” calculated for 10 carbon fillers (C) as targets.
Moreover, the length (H) of the long side of a carbon-type filler (C) means the length of the height direction (longitudinal direction) of the carbon-type filler (C) used as object.
On the other hand, the length (L) of the short side of the carbon-based filler (C) is the cross-section where the area is maximum among the cut surfaces orthogonal to the height direction (longitudinal direction) of the target carbon-based filler. If the cross section is a circle or an ellipse, it is a diameter or a major axis, and if the cross section is a polygon, it means the length of the longest side among the sides of the polygon.

  The average length (H) of the long side of the carbon-based filler (C) is preferably 0.01 to 2000 μm, more preferably 0.1 to 1000 μm, still more preferably 0.3 to 500 μm, and still more preferably. 0.5-100 μm.

  The average length (L) of the short side of the carbon-based filler (C) is preferably 1 to 1000 nm, more preferably 2 to 750 nm, more preferably 3 to 500 nm, still more preferably 5 to 100 nm, and still more preferably. Is 7-50 nm.

In the present invention, the content of the carbon-based filler (C) with respect to the total of 100 parts by mass of the components (A) and (B) is such that the adhesive property of the resulting conductive adhesive composition is good, From the viewpoint of reducing the surface resistivity of the conductive pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed from the agent composition, it is 0.1 to 7.0 parts by weight, preferably 0.2 to 5.0 parts by weight, More preferably, it is 0.3-3.5 mass part, More preferably, it is 0.5-2.5 mass part.
In this invention, even if the said content of a carbon-type filler (C) is 7.0 mass parts or less, the surface resistivity after irradiation of the energy ray of the adhesive layer formed from the said electroconductive adhesive composition Can be effectively reduced. Therefore, since content of a carbon-type filler (C) can be reduced, it can be set as the electroconductive adhesive composition excellent in adhesiveness.

  In addition, in one aspect of the present invention, the content of the carbon-based filler (C) with respect to the total amount (100% by mass) of the active ingredient (solid content) in the conductive pressure-sensitive adhesive composition is as described above. Preferably it is 0.01-10.0 mass%, More preferably, it is 0.1-7.0 mass%, More preferably, it is 0.2-5.0 mass%, More preferably, it is 0.3-3.5 mass %.

<Photopolymerization initiator (D)>
The conductive pressure-sensitive adhesive composition of one embodiment of the present invention preferably further contains a photopolymerization initiator (D).
Examples of the photopolymerization initiator (D) include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, methoxyacetophenone, and 2,2-dimethoxy-2-phenylacetophenone. Acetophenone compounds such as 2,2-diethoxyacetophenone; benzophenone compounds such as benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone; benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, aniso Benzoin ether compounds such as inmethyl ether; ketal compounds such as benzyldimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; 1-phenone-1,1-propanedione-2- (o-e) Photoactive oxime compounds such as toxicarbonyl) oxime; 1-hydroxycyclohexyl phenyl ketone, benzoin, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β-chloranthraquinone, 2, Examples include 4,6-trimethylbenzoyldiphenylphosphine oxide.
These photopolymerization initiators (D) may be used alone or in combination of two or more.

  1 aspect of this invention WHEREIN: Content of a photoinitiator (D) becomes like this. Preferably it is 0.1-15 mass parts with respect to 100 mass parts of polymeric compounds (B), More preferably, it is 0.2-10. Part by mass, more preferably 0.5 to 7 parts by mass.

<Crosslinking agent (E)>
The conductive adhesive composition of one embodiment of the present invention may further contain a crosslinking agent (E).
Examples of the crosslinking agent (E) include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, metal chelate-based crosslinking agents, amine-based crosslinking agents, amino resin-based crosslinking agents, and the like. It may be.
These crosslinking agents (E) may be used alone or in combination of two or more.
Among these, from the viewpoint of further improving the pressure-sensitive adhesive properties of the obtained conductive pressure-sensitive adhesive composition, an isocyanate-based crosslinking agent is preferable.

Examples of the isocyanate crosslinking agent include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4′-diisocyanate, Polyvalent isocyanate compounds such as diphenylmethane-2,4′-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, dicyclohexylmethane-2,4′-diisocyanate, lysine isocyanate Is mentioned.
The polyisocyanate compound may be a trimethylolpropane modified product of the above compound, a burette modified product reacted with water, or an isocyanurate modified product containing an isocyanurate ring.

  In one embodiment of the present invention, the content of the crosslinking agent (E) is preferably 0.01 to 15 parts by mass, more preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the polymerizable compound (B). More preferably, it is 0.1 to 5 parts by mass.

<Tackifier>
The conductive pressure-sensitive adhesive composition of one embodiment of the present invention may further contain a tackifier.
In the present invention, the “tackifier” means an oligomer having a mass average molecular weight (Mw) of less than 10,000 and having an action of drawing out the adhesiveness of the adhesive resin (A).
The mass average molecular weight (Mw) of the tackifier is preferably 400 to 4000, more preferably 800 to 1500, from the viewpoint of improving the adhesive force of the formed pressure-sensitive adhesive layer.

As a softening point of a tackifier, Preferably it is 110 degreeC or more, More preferably, it is 110-180 degreeC, More preferably, it is 115-175 degreeC, More preferably, it is 120-170 degreeC.
In the present invention, the “softening point” of the tackifier means a value measured according to JIS K2531.

Examples of the tackifier include rosin resins such as rosin resins, rosin phenol resins, and ester compounds thereof; hydrogenated rosin resins obtained by hydrogenating these rosin resins; terpene resins, aromatic modified terpene resins, terpene phenols A terpene resin such as a pentene resin; a hydrogenated terpene resin obtained by hydrogenating these terpene resins; a copolymerization of C5 fractions such as pentene, isoprene, piperine, 1.3-pentadiene produced by thermal decomposition of petroleum naphtha. Obtained by copolymerizing C5 petroleum resin obtained and hydrogenated petroleum resin of this C5 petroleum resin; C9 fraction such as indene, vinyltoluene, α- or β-methylstyrene produced by thermal decomposition of petroleum naphtha C9 petroleum resin and hydrogenated petroleum resin of this C9 petroleum resin.
In the present invention, the tackifiers may be used alone or in combination of two or more different softening points and structures.

  When the conductive adhesive composition of one embodiment of the present invention contains a tackifier, the content of the tackifier is preferably 1 to 200 parts by mass with respect to 100 parts by mass of the adhesive resin (A). More preferably, it is 5-160 mass parts, More preferably, it is 10-120 mass parts.

<General-purpose additive>
The conductive pressure-sensitive adhesive composition of one embodiment of the present invention may contain a general-purpose additive used for a general pressure-sensitive adhesive as necessary, as long as the effects of the present invention are not impaired.
Examples of such general-purpose additives include curing accelerators, crosslinking aids, antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes, and the like.
In the conductive adhesive composition of one embodiment of the present invention, when these general-purpose additives are contained, the content of each general-purpose additive is preferably 100 parts by mass of the adhesive resin (A). It is 0.01-10 mass parts, More preferably, it is 0.01-5 mass parts.

  The total content of components (A), (B), and (C) in the conductive adhesive composition of one embodiment of the present invention is based on the total amount (100 parts by mass) of the conductive adhesive composition. , Preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, still more preferably 90% by mass or more, and preferably 99.99% by mass or less, more preferably 99%. 90% by mass or less.

<Non-adhesive compound (β)>
According to the study by the present inventors, the non-adhesive compound (β) having a mass average molecular weight (Mw) of more than 5000 (hereinafter simply referred to as “non-adhesive compound (β)”) contained in the conductive adhesive composition. The presence of the polymerizable compound (B) is a factor that hinders the effect (the effect of reducing the surface resistivity and the effect of reducing the adhesive force after irradiation of the formed pressure-sensitive adhesive layer). I understood the fact that. In addition, the presence of the non-adhesive compound (β) causes corrosion of the adherend and generation of outgas.
From the above viewpoint, in the conductive adhesive composition of one embodiment of the present invention, the content of the non-adhesive compound (β) having a mass average molecular weight (Mw) of more than 5000 is the total amount of the conductive adhesive composition. On the other hand, it is preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less, and still more preferably 0.1% by mass or less.

In the present invention, the “non-adhesive compound” refers to a compound that is non-adhesive in itself and does not have an action of drawing out adhesiveness to other components such as the above-described tackifier. . Therefore, the above-mentioned “adhesive resin (A)” and “tackifier” do not correspond to non-adhesive compounds.
The above “non-adhesive compound (β)” refers to a compound having a mass average molecular weight (Mw) of more than 5000 among such non-adhesive compounds.

Specific examples of the non-adhesive compound (β) include a polymerizable compound (β1) having an energy ray-polymerizable group having a mass average molecular weight (Mw) of more than 5000, and a highly conductive compound having a mass average molecular weight (Mw) of more than 5000. And a polyether dispersant (β3) having a molecule (β2) and a mass average molecular weight (Mw) of more than 5000.
Examples of the energy ray polymerizable group possessed by the polymerizable compound (β1) include the same polymerizable groups as those possessed by the polymerizable compound (B) described above.
Examples of the polymerizable compound (β1) include a polyfunctional acrylate oligomer or polymer having an Mw of over 5000, a polyfunctional urethane acrylate oligomer or polymer having an Mw of over 5000, and a polyfunctional polyester acrylate having an Mw of over 5000. System oligomers or polymers.
Examples of the conductive polymer (β2) include polyaniline having an Mw of more than 5000, polythiophene having an Mw of more than 5000, polypyrrole having an Mw of more than 5000, and polyquinoxaline having an Mw of more than 5000.
Examples of the polyether dispersant (β3) include a carboxyl group-containing polyether having an Mw of more than 5000, an amino group-containing polyether having an Mw of more than 5000, and a nonionic polyether having an Mw of more than 5000.

  From the above viewpoint, the total content of the polymerizable compound (β1), the conductive polymer (β2), and the polyether dispersant (β3) is 5% by mass or less (preferably 3% by mass or less, more preferably 1 % By mass or less, more preferably 0.1% by mass or less.

[Configuration of conductive adhesive sheet]
The conductive pressure-sensitive adhesive sheet of the present invention is not particularly limited as long as it has a pressure-sensitive adhesive layer formed from the above-mentioned conductive pressure-sensitive adhesive composition, and may have other layers other than the pressure-sensitive adhesive layer. Good.
FIG. 1 is a cross-sectional view of the conductive pressure-sensitive adhesive sheet showing an example of the configuration of the conductive pressure-sensitive adhesive sheet of one embodiment of the present invention.
Examples of the conductive pressure-sensitive adhesive sheet according to one embodiment of the present invention include a conductive pressure-sensitive adhesive sheet 1a having a configuration in which a pressure-sensitive adhesive layer 11 is laminated on a substrate 12 as shown in FIG.
In addition, it is good also as the electroconductive adhesive sheet 1b which has the structure which laminated | stacked the peeling sheet 13 on the adhesive layer 11, as shown in FIG.1 (b) with respect to the structure of the electroconductive adhesive sheet 1a.

Furthermore, as another example of the conductive pressure-sensitive adhesive sheet of the present invention, pressure-sensitive adhesive layers 11 and 11 ′ are laminated on both surfaces of a base material 12 as shown in FIG. The conductive adhesive sheet 1c which has the structure which the peeling sheets 13 and 13 'laminated | stacked on the agent layers 11 and 11', respectively is mentioned.
The pressure-sensitive adhesive layer 11 and the pressure-sensitive adhesive layer 11 ′ of the conductive pressure-sensitive adhesive sheet 1c may be layers formed of the same type of conductive pressure-sensitive adhesive composition, and different types of conductive pressure-sensitive adhesive compositions. The layer formed from a thing may be sufficient.

Further, the conductive pressure-sensitive adhesive sheet of one embodiment of the present invention may be a substrate-less conductive pressure-sensitive adhesive sheet. As such a baseless conductive adhesive sheet, for example, as shown in FIG. 1 (d), a conductive adhesive sheet 1d having a configuration in which an adhesive layer 11 is sandwiched between two release sheets 13, 13 ′. Is mentioned.
Moreover, as a base-material-free electroconductive adhesive sheet contained in one aspect | mode of this invention, the electroconductivity which has the structure which wound what provided the adhesive layer on the single side | surface of the peeling sheet by which both surfaces were peel-processed was rolled. An adhesive sheet etc. are also mentioned.

Although the thickness of the adhesive layer of the electroconductive adhesive sheet of 1 aspect of this invention is suitably adjusted according to the use of an electroconductive adhesive sheet, Preferably it is 1-1200 micrometers, More preferably, it is 2-600 micrometers, More preferably, it is. It is 3-300 micrometers, More preferably, it is 5-150 micrometers.
When the thickness of the pressure-sensitive adhesive layer is 1 μm or more, good adhesive force can be expressed regardless of the type of adherend. On the other hand, if the thickness of the pressure-sensitive adhesive layer is 1200 μm or less, the resulting conductive pressure-sensitive adhesive sheet has good conductivity. Moreover, when the said electroconductive adhesive sheet is used as a wound body, the winding shift by the adhesive layer deform | transforming and the protrusion from the edge part of an adhesive layer can be suppressed.

<Base material>
The base material used for the conductive pressure-sensitive adhesive sheet of one embodiment of the present invention is appropriately selected according to the purpose of use of the conductive pressure-sensitive adhesive sheet, but may be an insulating base material including an insulating material, such as metal. The electroconductive base material containing the electroconductive material of this may be sufficient.

In the present invention, an insulating substrate refers to a substrate having a surface resistivity of 1.0 × 10 ¹⁴ Ω / □ or more (preferably 1.0 × 10 ¹⁶ Ω / □ or more).
Examples of the insulating base material include various types of paper such as fine paper, art paper, coated paper, glassine paper, and laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper base materials; Material: Polyolefin resin such as polyethylene resin and polypropylene resin, Polybutylene terephthalate resin, Polyester resin such as polyethylene terephthalate resin, Plastic film or sheet made of acetate resin, ABS resin, polystyrene resin, vinyl chloride resin, etc .; Mixture of these resins A plastic film or sheet comprising: a plastic film or sheet comprising a laminate of these plastic films or sheets.
The base material such as a plastic film or sheet may be unstretched, or may be stretched in a uniaxial direction or a biaxial direction such as longitudinal or lateral.
Further, these insulating base materials may further contain an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, a slip agent, an antiblocking agent, a colorant and the like.

Examples of the conductive substrate include a metal foil, a film or sheet obtained by laminating the metal foil with a resin or the like that forms the above-described insulating substrate, and a film obtained by performing a metal deposition process on the surface of the above-described insulating substrate. Or the sheet | seat, the film or sheet which performed the antistatic process on the surface of the above-mentioned insulating base material, the sheet | seat which knitted the metal wire in mesh shape, etc. are mentioned.
In addition, as a metal used for an electroconductive base material, aluminum, copper, silver, gold | metal | money etc. are mentioned, for example.

  Although there is no restriction | limiting in particular in the thickness of a base material, From a viewpoint of the ease of handling, Preferably it is 2-300 micrometers, More preferably, it is 10-250 micrometers, More preferably, it is 20-200 micrometers.

When the base material is a plastic film or sheet, from the viewpoint of improving the adhesion between the base material and the pressure-sensitive adhesive layer, the surface of the base material is subjected to a surface treatment such as an oxidation method or an unevenness method as necessary. It is preferable.
The oxidation method is not particularly limited, and examples thereof include a corona discharge treatment method, a plasma treatment method, chromic acid oxidation (wet), flame treatment, hot air treatment, and ozone / ultraviolet irradiation treatment. Moreover, it does not specifically limit as an uneven | corrugated method, For example, a sandblasting method, a solvent processing method, etc. are mentioned. These surface treatments are appropriately selected according to the type of the substrate, but the corona discharge treatment method is preferred from the viewpoint of improving the adhesion with the pressure-sensitive adhesive layer and operability. Moreover, primer treatment can also be performed.
Examples of the material used for the primer treatment include acrylic resins, urethane resins, and polyester resins.

<Peeling sheet>
As a release sheet used for the conductive adhesive sheet of one embodiment of the present invention, a release sheet that has been subjected to a double-sided release process, a release sheet that has been subjected to a single-sided release process, and the like are used. The thing etc. which apply | coated are mentioned.

Examples of the base material for the release sheet include paper base materials such as glassine paper, coated paper, and high-quality paper, laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper base materials, or polyethylene terephthalate resin, polybutylene. Examples thereof include polyester resin films such as terephthalate resin and polyethylene naphthalate resin, and plastic films such as polyolefin resin films such as polypropylene resin and polyethylene resin.
Examples of the release agent include rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins, long chain alkyl resins, alkyd resins, and fluorine resins.

  Although there is no restriction | limiting in particular in the thickness of a peeling sheet, Preferably it is 10-200 micrometers, More preferably, it is 25-150 micrometers.

[Method for producing conductive adhesive sheet]
There is no restriction | limiting in particular as a manufacturing method of the electroconductive adhesive sheet of this invention, For example, the above-mentioned each component is mix | blended and an electroconductive adhesive composition is prepared, The said electroconductive adhesive composition is made into the above-mentioned base material or It can be manufactured by forming a pressure-sensitive adhesive layer on a release sheet by known coating and drying.
If necessary, the conductive adhesive composition may be diluted by adding water or an organic solvent, and applied as a solution of the conductive adhesive composition on a substrate or a release sheet. .

In preparing the conductive pressure-sensitive adhesive composition, the carbon filler (C) is preferably mixed with a component such as the pressure-sensitive resin (A) in the form of a dispersion dispersed in a solvent.
Examples of the solvent used for the preparation of the carbon filler (C) dispersion include water and organic solvents, and organic solvents are preferable.
Examples of the organic solvent used for preparing the carbon filler (C) dispersion include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, 1-propanol, isopropyl alcohol, and dimethylformamide. , N-methylpyrrolidone, dimethyl sulfoxide and the like.
These organic solvents may be used alone or in combination of two or more.
Among these, at least one selected from methyl ethyl ketone, ethyl acetate, toluene, and isopropyl alcohol is preferable, and at least one selected from ethyl acetate and isopropyl alcohol is more preferable.

As a method for preparing the dispersion liquid of carbon-based filler (C), for example, carbon-based filler (x2) is added to a solvent, and ultrasonic waves (the amplitude is preferably 1 to 50 μm, more preferably 5 to 5 μm). 40 μm) and the like, and a method of preparing by giving vibration for a certain time.
The solid content concentration of the carbon-based filler (C) dispersion is preferably 0.01 to 60% by mass, more preferably 0.05 to 10% by mass, and still more preferably 0.1 to 3% by mass.

Examples of the organic solvent used in the preparation of the conductive adhesive composition include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, 1-propanol, isopropyl alcohol, dimethylformamide, N- Examples include methyl pyrrolidone and dimethyl sulfoxide.
These organic solvents may be used alone or in combination of two or more.
Among these, at least one selected from methyl ethyl ketone, ethyl acetate, toluene, and isopropyl alcohol is preferable, and at least one selected from ethyl acetate and isopropyl alcohol is more preferable.
As these organic solvents, the organic solvent used at the time of synthesizing the adhesive resin (A) or the organic solvent used when the carbon-based filler (C) is prepared in the form of a dispersion may be used as it is. One or more organic solvents other than the organic solvent used for the synthesis of the adhesive resin (A) and the dispersion of the carbon-based filler (C) so that the resulting solution of the conductive adhesive composition can be uniformly applied The organic solvent may be added.

  As solid content concentration of the solution of a conductive adhesive composition, Preferably it is 1-90 mass%, More preferably, it is 3-80 mass%, More preferably, it is 5-70 mass%, More preferably, it is 7-60 mass%. It is.

  Examples of the method for applying the conductive pressure-sensitive adhesive composition on the substrate or release sheet include spin coating, spray coating, bar coating, knife coating, roll knife coating, roll coating, and blade coating. , Die coating method, gravure coating method and the like.

Moreover, after apply | coating the solution of an electroconductive adhesive composition on a base material or a peeling sheet and forming a coating film, it is preferable to dry-process and remove the solvent contained in a coating film.
As the drying treatment, it is preferable to dry at a drying temperature of 25 to 150 ° C. (preferably 50 to 120 ° C.) for 10 seconds to 50 minutes (preferably 30 seconds to 30 minutes).
Furthermore, in order to increase the cohesive strength of the pressure-sensitive adhesive layer, after the drying treatment, for example, it is allowed to stand in an environment of 23 ° C. and 50% RH (relative humidity) for about 7 days to 30 days. It is preferable to sufficiently crosslink the pressure-sensitive adhesive layer (coating film) made of the product.

  After forming the pressure-sensitive adhesive layer on the base material or release sheet, the conductive pressure-sensitive adhesive sheet of one embodiment of the present invention is produced by appropriately bonding the base material or release sheet onto the pressure-sensitive adhesive layer as necessary. be able to.

[Physical properties of conductive adhesive sheet]
In the conductive adhesive sheet of the present invention, the adhesive force is reduced by irradiation with energy rays, and the surface resistivity is also reduced as compared with that before irradiation with energy rays. Therefore, the conductive pressure-sensitive adhesive sheet has good removability and can effectively suppress the generation of static electricity during peeling.
Also, the surface resistivity of the conductive adhesive sheet after energy beam irradiation is measured, and the degree of progress of curing of the adhesive layer of the conductive adhesive sheet is grasped depending on whether or not the value of the surface resistivity is reduced. be able to. That is, conventionally, the degree of curing of the pressure-sensitive adhesive layer has been grasped by direct contact with the pressure-sensitive adhesive layer or by infrared absorption spectrum analysis. On the other hand, when the conductive pressure-sensitive adhesive sheet of the present invention is used, the degree of cure of the pressure-sensitive adhesive layer can be grasped by measuring the change in the surface resistivity before and after irradiation with energy rays. The presence or absence of hardening of the layer can be confirmed.

In the conductive pressure-sensitive adhesive sheet of one embodiment of the present invention, the surface resistivity (ρ _S2 ) after energy ray irradiation of the pressure-sensitive adhesive layer of the conductive pressure-sensitive adhesive sheet and the surface resistivity of the pressure-sensitive adhesive layer before energy ray irradiation. The ratio [ρ _S2 / ρ _S1 ] to (ρ _S1 ) is preferably 9.0 × 10 ⁻² or less, more preferably 5.0 × 10 ⁻² or less, and ^still more preferably 9.0 × 10 ^−3. Hereinafter, it is still more preferably 9.0 × 10 ⁻⁴ or less.

The surface resistivity (ρ _S1 ) before energy ray irradiation of the pressure-sensitive adhesive layer of the conductive pressure-sensitive adhesive sheet of one embodiment of the present invention is preferably 1.0 × 10 ¹⁰ Ω / □ or less, more preferably 1.0. × 10 ⁹ Ω / □ or less, more preferably 5.0 × 10 ⁸ Ω / □ or less, and still more preferably 9.0 × 10 ⁷ Ω / □ or less.

In addition, the surface resistivity (ρ _S2 ) of the pressure-sensitive adhesive layer of the conductive pressure-sensitive adhesive sheet of one embodiment of the present invention after irradiation with energy rays is preferably 8.0 × 10 ⁶ Ω / □ or less, more preferably 1 0.0 × 10 ⁶ Ω / □ or less, more preferably 8.0 × 10 ⁵ Ω / □ or less, and still more preferably 3.0 × 10 ⁵ Ω / □ or less.

In addition, in this invention, said surface resistivity ((rho) _S1 ) and ((rho) _S2 ) are the values measured based on JISK7194, Specifically, the value measured by the method as described in an Example. Means.

The value of the peak top of the probe tack before energy ray irradiation of the conductive adhesive sheet of one embodiment of the present invention is preferably 100 N or more, more preferably 200 N or more, and further preferably 250 N or more.
Moreover, as a value of the peak top of the probe tack after energy ray irradiation of the conductive adhesive sheet of one embodiment of the present invention, it is preferably 1 to 180 N, more preferably 1 to 160 N, still more preferably 1 to 90, and still more. Preferably it is 1-60N.

The integral value of the probe tack before energy beam irradiation of the conductive adhesive sheet of one embodiment of the present invention is preferably 3000 or more, more preferably 4000 or more, and further preferably 5000 or more.
In addition, the integral value of the probe tack after the energy ray irradiation of the conductive adhesive sheet of one embodiment of the present invention is preferably 2000 or less, more preferably 1700 or less, still more preferably 1000 or less, and still more preferably 600 or less. is there.

  In the present invention, the peak top value and integral value of the probe tack described above are values measured in accordance with JIS Z0237 (1991), specifically, values measured by the method described in the examples. Means.

The physical property value of each component used in Examples and Comparative Examples was measured by the method described below.
<Mass average molecular weight (Mw)>
Using a gel permeation chromatograph device (product name “HLC-8020” manufactured by Tosoh Corporation), the value measured under the following conditions and measured in terms of standard polystyrene was used.
(Measurement condition)
・ Column: “TSK guard column HXL-H” “TSK gel GMHXL (× 2)” “TSK gel G2000HXL” (both manufactured by Tosoh Corporation)
-Column temperature: 40 ° C
・ Developing solvent: Tetrahydrofuran ・ Flow rate: 1.0 mL / min

<Resin acid value>
The measurement was performed according to JIS K0070.

<Aspect ratio of carbon filler>
Using a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, product name “S-4700”), 10 carbon filler particles extracted at random were observed, and the length and the short side of each long side were observed. The average value of 10 particles was defined as “long side length (H)” and “short side length (L)” of the filler. The aspect ratio (H / L) was calculated from “long side length (H) / short side length (L)”.

Examples 1-8, Comparative Examples 1-7
(1) Preparation of dispersion of carbon-based filler A carbon-based filler of the type and blending amount (solid content ratio with respect to 100 parts by mass (solid content) of acrylic resin) shown in Table 1 was added to ethyl acetate. Then, vibration is applied with ultrasonic waves from an ultrasonic disperser (42 kHz, 125 W) for 1 hour to disperse the carbon-based filler in ethyl acetate to prepare a carbon-based filler dispersion having a solid content concentration of 0.3% by mass. did.
(2) Preparation of solution of conductive pressure-sensitive adhesive composition For 100 parts by mass (solid content) of the acrylic resin of the type shown in Table 1, the type and amount (solid content ratio) of the polymerizable compound shown in Table 1 and The additive and the dispersion liquid of the carbon-based filler prepared in the above (1) (the dispersion liquid contains the carbon-based filler having the solid content shown in Table 1) were added. And it diluted with ethyl acetate suitably and stirred until it became uniform, and prepared the solution of the conductive adhesive composition with a solid content concentration of 17 mass%.
(3) Production of conductive pressure-sensitive adhesive sheet On the release-treated surface of a release sheet (manufactured by Lintec, product name “SP-PET509020”, thickness: 50 μm, polyethylene terephthalate film whose surface is peel-treated with a polybutadiene-based resin) A coating film was formed by applying the solution of the conductive adhesive composition prepared in (2) above. And the said coating film was dried and the adhesive layer of the thickness of Table 1 was formed.
Furthermore, a 50 μm-thick PET film (trade name “Lumirror”, manufactured by Toray Industries, Inc.) was bonded to the formed pressure-sensitive adhesive layer to produce a conductive pressure-sensitive adhesive sheet with a substrate.

The detail of each component of Table 1 used by the Example and the comparative example is as follows.
<Adhesive resin>
"Acrylic resin (1)": acrylic resin (BA / MA) composed of n-butyl acrylate (BA), methyl acrylate (MA), N-acryloylmorpholine (ACMO), and 2-hydroxyethyl acrylate (HEA) /ACMO/HEA=80.0/4.5/15.0/0.5 (parts by mass)), Mw = 500,000, acid value = 0 mgKOH / g.
"Acrylic resin (2)": acrylic resin (BA / AA = 90.0 / 10.0 (parts by mass)) consisting of n-butyl acrylate (BA) and acrylic acid (AA), Mw = 700,000 Acid value = 79 mg KOH / g.
"Acrylic resin (3)": acrylic resin (BA / HEA = 95.0 / 5.0 (parts by mass)) consisting of n-butyl acrylate (BA) and 2-hydroxyethyl acrylate (HEA), Mw = 400,000, acid value = 0 mg KOH / g.
"Acrylic resin (4)": acrylic resin (BA / MA / AAm / consisting of n-butyl acrylate (BA), methyl acrylate (MA), acrylamide (AAm), and 2-hydroxyethyl acrylate (HEA) HEA = 70.0 / 28.0 / 1.0 / 1.0 (parts by mass)), Mw = 400,000, acid value = 0 mgKOH / g.

<Polymerizable compound>
"Urethane oligomer (1)": polyfunctional urethane acrylate oligomer, Mw = 2000, number of energy ray polymerizable groups in one molecule = 5 to 7 (functional).
“Urethane oligomer (2)”: polyfunctional urethane acrylate oligomer, Mw = 6000, number of energy ray polymerizable groups in one molecule = 2 to 3 (functional).
“MOI-modified acrylic polymer (1)”: an acrylic prepolymer (BA / HEA = 83.0 / 17.0 (parts by mass)) composed of n-butyl acrylate (BA) and 2-hydroxyethyl acrylate (HEA) MOI-modified acrylic polymer (BA / HEA / MOI-modified HEA = 83.0 / 3.4 / 13.6 (mass) obtained by modifying 80% of HEA-derived hydroxyl groups with 2-methacryloyloxyethyl isocyanate (MOI) Part)), Mw = 600,000.
“MOI-modified acrylic polymer (2)”: acrylic prepolymer composed of n-butyl acrylate (BA), 2-hydroxyethyl acrylate (HEA) and methyl methacrylate (MMA) (BA / HEA / MMA = 60.0 / 25) MOI modified acrylic polymer (BA / HEA / MOI modified HEA / MMA) in which 80% of the hydroxyl groups derived from HEA of 0.0 / 15.0 (parts by mass) were modified with 2-methacryloyloxyethyl isocyanate (MOI). = 60.0 / 5.0 / 20.0 / 15.0 (parts by mass)), Mw = 430,000.

<Carbon filler>
"CNT (1)": manufactured by Nanosil Co., Ltd., trade name "NC7000", cylindrical multi-walled carbon nanotube, average aspect ratio (H / L): 200 (long side length (H): 2 μm, short side Length (L): 10 nm).

<Additives>
"Photoinitiator": BASF Corporation, trade name "Irgacure 184", 1-hydroxy-cyclohexyl-phenyl-ketone.
"Crosslinking agent": manufactured by Soken Chemical Co., Ltd., product name "TD-75", trimethylolpropane modified xylylene diisocyanate.

  About the probe tack | tuck and surface resistivity of the electroconductive adhesive sheet produced in the Example and the comparative example, it measured with the following method. These measurement results are shown in Table 1.

<Probe tack>
It measured based on JIS Z0237 (1991).
Specifically, the conductive adhesive sheets prepared in Examples and Comparative Examples were cut into a size of 10 mm × 10 mm and left for 24 hours in an environment of 23 ° C. and 50% RH (relative humidity). Used as (I).
After removing the release sheet of the test piece (I) to expose the adhesive layer, using a tacking tester (manufactured by Rigaku Corporation, PROBE TACK TESTER), in accordance with JIS Z0237 (1991) The probe tack of the conductive adhesive sheet before ultraviolet (UV) irradiation was measured.
In this probe tack, a stainless steel probe having a diameter of 5 mm was brought into contact with the surface of the pressure-sensitive adhesive layer of the test piece (I) with a contact load of 0.98 N / cm ² for 1 second, and then the probe was moved at a speed of 600 mm / second. The force required for peeling from the test piece is measured.
The measurement was performed twice, and the peak top value (unit: N) and integral value of the probe tack were calculated for each. The peak top value and integrated value of the probe tack described in Table 1 are the average values of the two times.
In addition, for the probe tack of the conductive adhesive sheet after ultraviolet (UV) irradiation, a UV irradiation device (product name “RAD2000m / 8” manufactured by Lintec Corporation) is used from the base material side of the test piece (I). The measurement was performed in the same manner as described above using a material irradiated with ultraviolet rays (light amount: 300 mJ / cm ² , illuminance: 230 mW).

<Surface resistivity>
The measurement was performed according to JIS K 7194.
Specifically, the produced conductive adhesive sheet was cut into a size of 20 mm × 40 mm and allowed to stand for 24 hours in an environment of 23 ° C. and 50% RH (relative humidity) as a test piece (II). did.
A low resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd., product name “Loresta GP MCP-T610”) is used for the adhesive layer exposed by removing the release sheet of the test piece (II). Then, according to JIS K 7194, the surface resistivity [ρ _S1 ] of the conductive adhesive sheet before ultraviolet (UV) irradiation was measured. The surface resistivity was measured three times, and Table 1 shows the average value of the three times.
Moreover, about the surface resistivity [ρ _S2 ] of the conductive adhesive sheet after ultraviolet (UV) irradiation, from the base material side of the test piece (II), a UV irradiation device (product name “RAD2000m / 8” manufactured by Lintec Corporation) is used. ”), And was irradiated with ultraviolet rays (light amount: 300 mJ / cm ² , illuminance: 230 mW), and measured in the same manner as described above.
Furthermore, ultraviolet (UV) ratio of the electrically conductive adhesive sheet surface resistivity after irradiation with [[rho _S2] and ultraviolet (UV) conductive adhesive sheet surface resistivity before irradiation _{[ρ S1] ([ρ S2} ] / [Ρ _S1 ]) was also calculated.

Compared with Comparative Examples 1-7, the conductive adhesive sheet produced in Examples 1-8 has a large amount of reduction in surface resistivity after UV irradiation, and the surface resistivity after UV irradiation is also low. Therefore, it can be said that the conductive adhesive sheets of Examples 1 to 8, which are one embodiment of the present invention, have excellent antistatic properties and conductivity that can suppress the generation of static electricity during peeling.
Moreover, from the values of the probe tack before and after UV irradiation, it can be seen that the conductive adhesive sheets of Examples 1 to 8 have better removability than Comparative Examples 1 to 7.

The conductive pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed from the conductive pressure-sensitive adhesive composition of the present invention has excellent adhesion and removability, and excellent antistatic properties that can suppress the generation of static electricity during peeling. And conductivity.
Therefore, the conductive adhesive sheet according to one aspect of the present invention is, for example, an adhesive sheet used for the purpose of temporarily fixing parts or protecting circuits when producing electrical parts, electronic parts, semiconductor parts, etc. It is suitable as a pressure-sensitive adhesive sheet for temporary fixing used for transporting conductive materials and conductive materials.

1a, 1b, 1c, 1d conductive adhesive sheet 11, 11 'adhesive layer 12 base material 13, 13' release sheet

Claims (11)

On an insulating substrate having a surface resistivity of 1.0 × 10 ¹⁴ Ω / □ or more,
Adhesive resin (A) containing acrylic resin (A1), mass average molecular weight (Mw) is 5000 or less, polymerizable compound (B) having an energy ray polymerizable group, and average aspect ratio is 5 or more A carbon-based filler (C) containing a carbon nanomaterial is contained, and the content of the carbon-based filler (C) is 0.1 to 7.0 with respect to a total of 100 parts by mass of the components (A) and (B). The electroconductive adhesive sheet which has an adhesive layer formed from the electroconductive adhesive composition which is a mass part . The surface resistivity after energy ray irradiation of the pressure-sensitive adhesive layer (ρ _S2), wherein the ratio of the surface resistivity before the energy ray irradiation of the pressure-sensitive adhesive layer ([rho _S1) [ρ _{S2 /} ρ _S1] is 9.0 × ^{10 -2} or less, a conductive adhesive sheet according to claim 1. The content of the weight average molecular weight (Mw) of 5000 than nonstick compound (beta) is, relative to the total amount of the conductive adhesive composition, 5% by mass or less, according to claim 1 or 2 Conductive adhesive sheet . The non-adhesive compound (β) is a polymerizable compound (β1) having an energy ray polymerizable group having a mass average molecular weight (Mw) exceeding 5000, and a conductive polymer (β2) having a mass average molecular weight (Mw) exceeding 5000. And the electroconductive adhesive sheet of Claim 3 which is 1 or more types chosen from the polyether-type dispersing agent ((beta) 3) whose mass mean molecular weight (Mw) exceeds 5000. The conductive adhesive sheet according to any one of claims 1 to 4 , wherein the polymerizable compound (B) comprises a polyfunctional urethane acrylate oligomer. The conductive adhesive sheet according to any one of claims 1 to 5 , wherein the number of groups in one molecule of the energy beam polymerizable group of the polymerizable compound (B) is 4 to 10. The electrically conductive adhesive sheet of any one of Claims 1-6 whose content of a polymeric compound (B) is 10-150 mass parts with respect to 100 mass parts of components (A). The conductive adhesive sheet according to any one of claims 1 to 7 , wherein the acid value of the adhesive resin (A) is 20 mgKOH / g or less. The electroconductivity of any one of Claims 1-8 whose content of the structural unit derived from (meth) acrylic acid with respect to the whole quantity of the structural unit which acrylic resin (A1) has is 5 mass% or less. Adhesive sheet . The electroconductive adhesive sheet of any one of Claims 1-9 used for conveyance of an insulating material. The electroconductive adhesive sheet of any one of Claims 1-9 used for conveyance of an electroconductive material.