KR20130131236A - Electroconductive thin adhesive sheet - Google Patents

Abstract

The purpose of the present invention is to provide an electroconductive thin adhesive sheet with improved adhesive property, productivity, conductivity, and adhesive property. To solve the problem, the thin adhesive sheet has thickness of 40 micrometers or less and includes a conductive substrate and a conductive adhesive layer including conductive particles, wherein the particle diameter d50 of a conductive particle is 4-12 micrometers, d85 is 6-15 micrometers, and the thickness of the adhesive layer is 6-12 micrometers. Accordingly, the thin adhesive sheet improves productivity, adhesive property, and conductivity.

Description

Conductive thin adhesive sheet {ELECTROCONDUCTIVE THIN ADHESIVE SHEET}

This invention relates to the electroconductive thin adhesive sheet which has an adhesive base material and the adhesive layer containing electroconductive particle.

For ease of handling, the conductive adhesive sheet is used for shielding against unnecessary leakage electromagnetic waves radiated from electricity, electronic devices, etc., for shielding harmful space electromagnetic waves generated from other electricity, electronic devices, grounding for preventing static electricity, and the like. In recent years, with the miniaturization and thinning of electric and electronic equipment, the conductive adhesive sheet used for these is also required to be thinned.

As a thin conductive adhesive sheet, the adhesive sheet which has the adhesive layer which consists of an electroconductive adhesive which disperse | distributed the electroconductive filler in an adhesive substance on the electrically conductive base material is disclosed (refer patent documents 1-2). Although it is disclosed that these adhesive sheets have favorable electroconductivity and adhesiveness, when it is set as the ultra-thin adhesive sheet responding to the request of the recent improved thinning, electroconductivity and adhesiveness improvement is More is required. Moreover, in making ultra-thin the adhesive sheet which has an adhesive layer containing an electrically conductive filler, coating streaks easily enter in an adhesive layer, and favorable productivity may not be obtained.

Japanese Patent Application Laid-Open No. 2004-263030 JP 2009-79127 A

The problem to be solved by the present invention is to provide a conductive thin pressure-sensitive adhesive sheet having good adhesion and conductivity even in a thin shape and excellent in productivity.

In this invention, it is a thin adhesive sheet with a total thickness of 40 micrometers or less, Comprising: An electroconductive adhesive layer containing an electroconductive base material and electroconductive particle, The particle diameter d50 of the said electroconductive particle is 4-12 micrometers, and d85 is 6- It is 15 micrometers and the thickness of the said adhesive layer is found to be 6-12 micrometers, and it discovered that it was thin and could implement suitable productivity with favorable adhesiveness and electroconductivity, and the said subject Solved.

The conductive thin pressure-sensitive adhesive sheet of the present invention is extremely thin, has good adhesion to an adherend, has conductivity, and has suitable productivity, and therefore is suitable for shielding electromagnetic waves used in electricity, electronic devices, and the like. It is useful for the shielding of harmful space electromagnetic waves generated and for fixing the ground of antistatic charge. In particular, the thinning progresses, and the present invention can be suitably applied to the use of a portable electronic device having a strict volume limitation in the casing.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows an example of the structural example of the electroconductive thin adhesive sheet of this invention.
It is a figure which shows an example of a structural example of the electroconductive thin adhesive sheet of this invention.

The electroconductive adhesive sheet of this invention is a thin adhesive sheet with a total thickness of 40 micrometers or less, has an electroconductive base material and the electroconductive adhesive layer containing electroconductive particle, particle diameter d50 of the said electroconductive particle is 4-12 micrometers, and d85 Is 6-15 micrometers, and the said adhesive layer is electroconductive thin adhesive sheet whose thickness is 6-12 micrometers.

EMBODIMENT OF THE INVENTION Below, the electroconductive adhesive sheet of this invention is demonstrated in detail based on the component. In addition, the "sheet" in this invention means the form which provided the thin layer of the at least 1 layer of conductive adhesive on the electroconductive base material or the peeling sheet, For example, it is a sheet, roll shape, or thin plate shape, a strip | belt. All product forms, such as a shape (tape shape), are included.

(Conductive particles)

As for the electroconductive particle used for the electroconductive adhesive sheet of this invention, particle diameter d50 is 4-12 micrometers, and particle diameter d85 is 6-15 micrometers. d50 becomes like this. More preferably, it is 4-10 micrometers, More preferably, it is 5-9 micrometers, It is most preferable that it is 6-8 micrometers. D85 is more preferably 6.5 to 14 µm, still more preferably 7 to 13 µm, and most preferably 8 to 11 µm. In addition, the particle size d50 is a 50% cumulative value (median diameter) in the particle size distribution. The particle diameter d85 is an 85% cumulative value. These particle diameters are the values measured by a laser analysis and scattering method. Examples of the measuring device include Nikkiso Micro Track MT3000 II, Shimadzu Seisakusho laser diffraction particle size distribution analyzer SALD-3000 and the like.

It is preferable that the particle diameter d50 of electroconductive particle is 50 to 150% of the adhesive layer thickness, and d85 is 80 to 200%. By using electroconductive particle of the said range, electroconductivity, adhesiveness, and productivity are easy to compatible. d50 is more preferably 60 to 120%, and most preferably 70 to 100%. d85 is more preferably 100 to 150%, and most preferably 110 to 140%.

Examples of the material of the conductive particles include metal powder particles such as gold, silver, copper, nickel, and aluminum, conductive resins such as carbon and graphite, resins, solid glass beads, and those having metal coatings on the surfaces of hollow glass beads. Can be used. Especially, since nickel powder particle | grains, copper powder particle | grains, or silver powder particle | grains are excellent in electroconductivity, adhesiveness, and productivity, it is preferable. As a more preferable thing, the surface needle-shaped nickel particle which has many needle-like shapes on the particle | grain surface manufactured by the carbonyl method, or the surface needle-shaped particle | grains was made to smooth and processed into spherical particle, Copper powder and silver powder manufactured by the ultrahigh-pressure swinging water atomization method are mentioned. You may use these electroconductive particle in mixture of 2 or more types so that d50 and d85 may fall in the said range. It is especially preferable to mix the particle diameter d50 of 10-12 micrometers or more and 5-7 micrometers because it is excellent in electroconductivity.

As a shape of electroconductive particle, spherical or surface needle shape is preferable. The aspect ratio is not particularly limited, but is preferably 1 to 2, more preferably 1 to 1.5, and most preferably 1 to 1.2. Aspect ratio can be measured with a scanning electron microscope.

Although it does not specifically limit as a tap density of electroconductive particle, 2-7 g / cm <3> is preferable because it is hard to settle and aggregate at the time of production. More preferably, it is 3-6 g / cm <3>, and 4-5 g / cm <3> is the most preferable.

Although it does not specifically limit as content of the electroconductive particle in a conductive adhesive layer, 10-65 mass% in a conductive adhesive layer is preferable, More preferably, it is 20-50 mass%, More preferably, it is 22-41 mass%. , 28-38 mass% are the most preferable. By making content of electroconductive particle into the said range, electroconductivity, adhesiveness, and productivity will become easy to compatible.

(Adhesive composition)

The electroconductive adhesive layer used for the electroconductive adhesive sheet of this invention is formed from the adhesive composition containing the said electroconductive particle. The adhesive composition used for a normal adhesive sheet can be used for the adhesive composition which forms an electroconductive adhesive layer. Examples of the pressure-sensitive adhesive composition include (meth) acrylic pressure sensitive adhesives, urethane pressure sensitive adhesives, synthetic rubber pressure sensitive adhesives, natural rubber pressure sensitive adhesives, silicone pressure sensitive adhesives, and the like, but (meth) acrylates alone or in air of (meth) acrylates and other monomers The (meth) acrylic pressure-sensitive adhesive composition in which an acrylic copolymer made of a copolymer is used as a base polymer and in which additives such as a tackifying resin and a crosslinking agent are blended, can be preferably used in terms of weather resistance and heat resistance.

As an acryl-type copolymer, the acryl-type copolymer which makes a C1-C14 (meth) acrylate monomer the main monomer component can be used preferably, As a C1-C14 (meth) acrylate, for example, methyl ( Meta) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl Monomers, such as (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, cyclohexyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate, These 1 are mentioned. Species or two or more kinds are used. Especially, the (meth) acrylate of 4-12 carbon atoms of an alkyl group is preferable, and the (meth) acrylate which has a C4-C9 linear or branched structure is more preferable. Especially, n-butyl acrylate and 2-ethylhexyl acrylate can be used preferably, and these may be used independently or may be used together, respectively.

It is preferable that it is 80-98.5 mass% in the monomer component which comprises an acrylic copolymer, and, as for content of C1-C14 (meth) acrylate in an acryl-type copolymer, it is more preferable that it is 90-98.5 mass%.

Moreover, it is also preferable that the acrylic copolymer used for this invention copolymerizes a high polar vinyl monomer, As a high polar vinyl monomer, the vinyl monomer which has a carboxyl group, the vinyl monomer which has a hydroxyl group, the vinyl monomer which has an amide group, etc. are mentioned, 1 type, or 2 or more types of these is used. Especially, since a carboxyl group-containing monomer is easy to adjust the adhesiveness of an adhesive to the suitable range, it can be used preferably.

As a vinyl monomer which has a carboxyl group, acrylic acid, methacrylic acid, itaconic acid, maleic acid, (meth) acrylic acid dimer, crotonic acid, ethylene oxide modified succinic acid acrylate, etc. can be used, Especially, acrylic acid is used as a copolymerization component. It is preferable.

When using the vinyl monomer which has a carboxyl group, it is preferable that the content is 0.2-15 mass% in the monomer component which comprises an acryl-type copolymer, It is more preferable that it is 0.4-10 mass%, It is 0.5-6 mass% More preferred. By containing in the said range, it is easy to adjust the adhesiveness of an adhesive to the suitable range.

As a monomer which has a hydroxyl group, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth), for example Hydroxyl group-containing (meth) acrylates, such as acrylate, can be used.

Moreover, as a monomer which has an amide group, N-vinylpyrrolidone, N-vinyl caprolactam, acryloyl morpholine, acrylamide, N, N- dimethyl acrylamide, etc. are mentioned.

Examples of other highly polar vinyl monomers include sulfonic acid group-containing monomers such as vinyl acetate, ethylene oxide-modified succinate acrylate and 2-acrylamide-2-methylpropanesulfonic acid, 2-methoxyethyl (meth) acrylate and 2-phenoxy. Terminal alkoxy modified (meth) acrylates, such as the ethyl ethyl (meth) acrylate, are mentioned.

As for content of a high polar vinyl monomer, it is preferable that the total amount is 0.2-15 mass% in the monomer component which comprises an acryl-type copolymer, It is more preferable that it is 0.4-10 mass%, It is more preferable that it is 0.5-6 mass% Do. By containing in the said range, it is easy to adjust the adhesiveness of an adhesive to the suitable range.

Although an acryl-type copolymer can be obtained by copolymerizing by well-known methods, such as a solution polymerization method, a block polymerization method, suspension polymerization method, and emulsion polymerization method, in terms of a production cost and productivity, solution polymerization is carried out. It is preferable to superpose | polymerize by. As for the average molecular weight of an acryl-type copolymer, 300,000-1,500,000 are preferable, More preferably, it is 500,000-1,200,000.

(Gel fraction of adhesive)

It is preferable that the (meth) acrylic adhesive used for the electroconductive adhesive sheet of this invention forms a three-dimensional crosslinked structure for the improvement of cohesion force. As an index of crosslinking structure formation, the gel fraction which appears as an insoluble content after immersing in toluene which is a good solvent of a (meth) acrylic-type adhesive for 24 hours is used. In that case, it is preferable that it is 25-60 mass%, More preferably, it is 30-40 mass%. When the gel fraction is less than 25% by mass, the cohesion force in the shear direction is insufficient, and when the gel fraction exceeds 60% by mass, the peeling resistance is lowered.

The gel fraction is calculated by the following formula.

Gel fraction (mass%) = {(adhesive mass after immersion in toluene) / (adhesive mass before immersion in toluene)} × 100

* Adhesive mass = (mass of conductive adhesive sheet)-(mass of substrate)-(mass of conductive particles)

In formation of a crosslinked structure, well-known crosslinking agents, such as an isocyanate type crosslinking agent, an epoxy type crosslinking agent, a chelate type crosslinking agent, and an aziridine type crosslinking agent, are mentioned, for example. It is preferable to select the kind of crosslinking agent according to the functional group of the monomer component mentioned above. As addition amount of a crosslinking agent, if a gel fraction is the quantity which can be adjusted to 25-60 mass%, it does not specifically limit.

(additive)

In order to improve the adhesive force of an electroconductive adhesive sheet, you may add tackifying resin further. The tackifying resin added to the electroconductive adhesive of the particle-dispersion type used by this invention is petroleum resin, such as rosin-type resin, terpene-type resin, aliphatic (C5 type), and aromatic (C9 type), styrene resin, and phenolic resin. , Xylene-based resins, methacryl-based resins, and the like. Especially, rosin-type resin is preferable and polymerization rosin-type resin is especially preferable. As addition amount of tackifying resin, it is preferable to add 10-50 mass% with respect to 100 mass parts of (meth) acrylic-type copolymers.

Various additives may be added to the adhesive used for the conductive adhesive sheet of this invention as needed. As said additive, a plasticizer, a softener, a metal inert, antioxidant, a pigment, dye, etc. are mentioned, for example, It is used suitably as needed.

(Particle Dispersion Conductive Adhesive Composition)

As a method of disperse | distributing the said electroconductive particle of the said adhesive substance, the method of disperse | distributing an adhesive substance, a solvent, electroconductive particle, and an additive with a dispersion stirrer is mentioned. As a commercially available dispersing stirrer, an Inoue Seisakusho dissolver, a butterfly mixer, a BDM biaxial mixer, and a planetary mixer are mentioned. Especially, the dissolver and butterfly mixer to which the moderate shearing | shear is applied with little thickening of the adhesive in stirring are preferable.

Although it does not specifically limit as a viscosity of a particle | grain dispersion | distribution type conductive adhesive composition, 100-10000 Mpa * s is preferable, More preferably, it is 500-8000 Mpa * s, Most preferably, it is 1000-3000 Mpa * s. When viscosity is low, electroconductive particle tends to settle easily with time. On the other hand, when the viscosity is too high, coating streaks are likely to occur during thin film coating. As a adjustment method of a viscosity, adjustment of content and a kind of a solvent, and adjustment of the kind and molecular weight of an adhesive substance are mentioned. Especially, since adjustment of content and a kind of a solvent is simple, it is preferable.

Although it does not specifically limit as solid content of a particle | grain dispersion | distribution type conductive adhesive composition, 10 to 70% is preferable, More preferably, it is 30 to 55%, Most preferably, it is 43 to 50%.

(Thickness of the conductive adhesive layer)

The thickness of the adhesion layer of an electroconductive adhesive sheet is 6-12 micrometers. Preferably it is 7-11 micrometers, Especially, it is especially preferable that it is 8-10 micrometers. If it is the said range, since a coating stripe hardly arises and electroconductivity is excellent, it is preferable.

(Conductive base)

As a conductive base material used for the conductive adhesive sheet of this invention, a metal foil base material, a graphite base material, etc. are mentioned. As a material of metal foil, gold, silver, copper, aluminum, nickel, iron, tin, and these alloys are mentioned. Especially, aluminum foil and copper foil are preferable at the point of workability and cost. More preferably, the roughened electrolytic copper foil is preferable because of its excellent conductivity. Examples of commercially available electrolytic copper foil include CF-T9FZ-HS-9 (9 µm) and CF-T9FZ-HS-9 (9 µm) manufactured by Fukuda Kinzoku Hakuhoon Co., Ltd. Examples of commercially available rolled copper foil include TCU-H-8-RT (8 µm) manufactured by Nippon Seihaku Co., Ltd. and TPC (6 µm) manufactured by JX Nikko Nike Sekikinzoku Corporation.

As thickness of an electroconductive base material, 1-24 micrometers is preferable, More preferably, it is 3-16 micrometers, Most preferably, it is 6-12 micrometers. If it is the said range, since thinning is possible and it is excellent in workability, it is preferable.

(Peel liner)

In the electroconductive adhesive sheet of this invention, a peeling liner can be laminated | stacked on an adhesion layer. A release liner is not specifically limited, For example, paper, such as kraft paper, glassine paper, and quality paper, resin films, such as polyethylene, a polypropylene (OPP, CPP), and a polyethylene terephthalate, laminated | stacked the said papers and a resin film A conventionally well-known thing can be used, such as laminating paper and the said papers which performed peeling process, such as a silicone resin, on the one or both surfaces of what carried out the filling process with clay, polyvinyl alcohol, etc., can be used.

(Configuration of the Conductive Adhesive Sheet)

The electroconductive adhesive sheet of this invention is an electroconductive adhesive sheet which has an electroconductive adhesive layer formed from the adhesive composition containing said electroconductive particle, and an electroconductive base material, and the total thickness is an adhesive sheet of 40 micrometers or less. The conductive adhesive sheet of the present invention has a very thin configuration having a total thickness of 40 µm or less, which can respond to requests for thinning of portable electronic devices and the like, and by using the conductive adhesive layer as an adhesive layer, good adhesion, conductivity and Productivity can be realized.

The total thickness of the electroconductive adhesive sheet is 40 micrometers or less, Preferably it is 35 micrometers or less, More preferably, it is 30 micrometers or less, It is especially preferable that it is 20 micrometers or less. By being in the said range, thickness of an adhesive sheet can be reduced, ensuring adhesiveness and electroconductivity, and can contribute to thickness reduction of a portable electronic device. In addition, the total thickness of an electroconductive adhesive sheet is the thickness of the electroconductive adhesive sheet itself which does not contain a peeling liner.

Examples of suitable configurations of the conductive adhesive sheet of the present invention are shown in FIGS. 1 and 2. FIG. 1: is a single-sided adhesive sheet which laminated | stacked the conductive adhesive layer 2 on the conductive base material 1. FIG. 2 is a double-sided adhesive sheet which laminated | stacked the conductive adhesive layer 2 on both surfaces of the electroconductive base material 1. In these structures, the structure in which the peeling liner was provided in the surface of the adhesive layer 2 can be used preferably.

[Example]

Although an Example is demonstrated concretely below, this invention is not limited to these Examples.

(Adjustment of Acrylic Adhesive Composition)

[Preparation of Acrylic Adhesive Composition 1]

75.0 parts by mass of n-butyl acrylate, 19.0 parts by mass of 2-ethylhexyl acrylate, 3.9 parts of vinyl acetate, 2.0 parts of acrylic acid, and 2-hydroxyethyl acrylate in a reaction vessel equipped with a cooling tube, a stirrer, a thermometer, and a dropping funnel. 0.1 mass part and 0.1 mass part of 2,2'- azobisisobutylnitrile are melt | dissolved in 100 mass parts of ethyl acetate as a polymerization initiator, and it superposes | polymerizes at 80 degreeC for 12 hours after nitrogen substitution, and the acrylic copolymer of a mass average molecular weight 600,000 Got it. 10 mass parts of superposition | polymerization rosin pentaerythritol ester (made by Arakawa Kagaku Co., Ltd., Fencer D-135, softening point 135 degreeC) with respect to 100 mass parts of solid content of this acryl-type copolymer solution, a disproportionated rosin glycerin ester (Arakawaka) 10 mass parts of Gaku Co., Ltd. product, superester A-100, softening point 100 degreeC) were mix | blended, resin solid content concentration was adjusted to 45 mass% with ethyl acetate, and the acrylic adhesive composition 1 was adjusted.

[Preparation of Acrylic Adhesive Composition 2]

96.0 parts by mass of n-butyl acrylate, 0.1 parts by mass of 2-hydroxyethyl acrylate, 3.9 parts by mass of acrylic acid and 2,2'-azobis as a polymerization initiator in a reaction vessel equipped with a cooling tube, a stirrer, a thermometer and a dropping funnel. 0.1 mass part of isobutyl nitrile was melt | dissolved in 100 mass parts of ethyl acetate, and it superposed | polymerized at 80 degreeC for 12 hours after nitrogen substitution, and obtained the acrylic copolymer of the mass mean molecular weight 600,000. 10 mass parts of superposition | polymerization rosin pentaerythritol ester (made by Arakawa Kagaku Co., Ltd., Fencer D-135, softening point 135 degreeC) with respect to 100 mass parts of solid content of this acryl-type copolymer solution, a disproportionated rosin glycerin ester (Arakawaka) 10 mass parts of Gaku Co., Ltd. product, superester A-100, softening point 100 degreeC) were mix | blended, resin solid content concentration was adjusted to 45 mass% with ethyl acetate, and the acrylic adhesive composition 2 was adjusted.

(Creation of Particle Dispersion Conductive Adhesive Composition)

[Creation of Particle Dispersion Conductive Adhesive Composition A]

Nickel powder NI123J (d50: 6.3 micrometers, d85: 10.0 micrometers, tap density: 4.3 g / cm <3>, NIK Corporation made by Fukuda Kinzoku Hakuko Co., Ltd.) with respect to 100 mass parts (45 mass parts of solid content) of the said acrylic adhesive composition 1 was used. 22.5 parts by mass of a smoothing treatment) and 2 parts by mass of a crosslinking agent Bannock NC40 (isocyanate crosslinking agent made by DIC, 40 mass% of solid content) were mixed, and the solid content concentration was adjusted to 47 mass% with ethyl acetate, and the mixture was stirred for 10 minutes. It mixed and created particle-dispersion type conductive adhesive A.

[Creation of Particle Dispersion Conductive Adhesive Composition B]

Nickel powder NI123J (d50: 6.3 micrometers, d85: 10.0 micrometers, tap density: 4.3 g / cm <3>, NIK Corporation made by Fukuda Kinzoku Hakuko Co., Ltd.) with respect to 100 mass parts (45 mass parts of solid content) of the said acrylic adhesive composition 1 was used. Smoothing treatment) 13.5 parts by mass, crosslinking agent Bannock NC40 (isocyanate-based crosslinking agent made by DIC, 40 parts by mass) of 2 parts by mass was added, the solids concentration was adjusted to 47% by mass with ethyl acetate, and the mixture was stirred for 10 minutes. It mixed and created particle-dispersion type conductive adhesive B.

[Creation of Particle Dispersion Conductive Adhesive Composition C]

Nickel powder NI123J (d50: 6.3 micrometers, d85: 10.0 micrometers, tap density: 4.3 g / cm <3>, NIK Corporation made by Fukuda Kinzoku Hakuko Co., Ltd.) with respect to 100 mass parts (45 mass parts of solid content) of the said acrylic adhesive composition 1 was used. 31.5 parts by mass of a smoothing treatment) and 2 parts by mass of crosslinking agent Bannock NC40 (isocyanate crosslinking agent made by DIC, 40 mass% of solid content) were mixed, the solid content concentration was adjusted to 47 mass% with ethyl acetate, and the mixture was stirred for 10 minutes. It mixed and created particle-dispersion type conductive adhesive C.

[Creation of Particle Dispersion Conductive Adhesive Composition D]

Nickel powder NI123J (d50: 6.3 micrometers, d85: 10.0 micrometers, tap density: 4.3 g / cm <3>, NIK Corporation made by Fukuda Kinzoku Hakuko Co., Ltd.) with respect to 100 mass parts (45 mass parts of solid content) of the said acrylic adhesive composition 1 was used. 22.5 parts by mass of a smoothing treatment) and 2 parts by mass of crosslinking agent Bannock NC40 (isocyanate crosslinking agent made by DIC, 40 mass% of solids), the solids concentration was adjusted to 55 mass%, mixed with a dispersion stirrer for 10 minutes, and particles Dispersion conductive adhesive D was created.

[Creation of Particle Dispersion Conductive Adhesive Composition E]

Nickel powder NI123J (d50: 6.3 micrometers, d85: 10.0 micrometers, tap density: 4.3 g / cm <3>, NIK Corporation made by Fukuda Kinzoku Hakuko Co., Ltd.) with respect to 100 mass parts (45 mass parts of solid content) of the said acrylic adhesive composition 1 was used. 22.5 parts by mass of a smoothing treatment) and 2 parts by mass of a crosslinking agent Bannock NC40 (isocyanate crosslinking agent made by DIC, 40 mass% of solids) were mixed, the solid content concentration was adjusted to 40 mass% with ethyl acetate, and the mixture was stirred for 10 minutes. It mixed and created particle-dispersion type conductive adhesive E.

[Creation of Particle Dispersion Conductive Adhesive Composition F]

Copper powder CU-HWQ 5 micrometers (d50: 4.3 micrometers, d85: 7.0 micrometers) made by Fukuda Kinzoku Hakuhoon Co., Ltd. with respect to 100 mass parts (45 mass parts of solid content) of the said acrylic adhesive composition 1, tap density: 4.8 g / cm <3>, ultrahigh pressure 22.5 parts by mass of swirling water atomized ultrafine powder) and 2 parts by mass of crosslinking agent Bannock NC40 (isocyanate-based crosslinking agent made by DIC, 40 mass% of solids) were mixed, and the solid content concentration was adjusted to 47 mass% with ethyl acetate. It mixed for 10 minutes and created the particle | grain dispersion | distribution type conductive adhesive F.

[Creation of Particle Dispersion Conductive Adhesive Composition G]

Copper powder CU-HWQ 10 micrometers (d50: 10.0micrometer, d85: 13.0micrometer, tap density: 4.7g / cm <3>, ultrahigh pressure manufactured by Fukuda Kinzoku Hakuhoon Co., Ltd. with respect to 100 mass parts (45 mass parts of solid content) of the said acrylic adhesive composition 1 22.5 parts by mass of swirling water atomized ultrafine powder) and 2 parts by mass of crosslinking agent Bannock NC40 (isocyanate-based crosslinking agent made by DIC, 40 mass% of solids) were mixed, and the solid content concentration was adjusted to 47 mass% with ethyl acetate. It mixed for 10 minutes and created the particle | grain dispersion | distribution type electroconductive adhesive G.

[Creation of Particle Dispersion Conductive Adhesive Composition H]

Nickel powder NI123J (d50: 6.3 micrometers, d85: 10.0 micrometers, tap density: 4.3 g / cm <3>, NIK Corporation made by Fukuda Kinzoku Hakuko Co., Ltd.) with respect to 100 mass parts (45 mass parts of solid content) of the said acrylic adhesive composition 1 was used. Smoothed) 21.4 parts by mass, 1.1 parts by mass of nickel powder NI123 (d50: 10.7, d85: 25.0 µm), and 2 parts by mass of crosslinking agent Bannock NC40 (isocyanate crosslinking agent made by DIC, 40% by mass) And solid content concentration was adjusted to 47 mass% with ethyl acetate, it mixed for 10 minutes with the dispersion stirrer, and particle-dispersion type conductive adhesive H was created. 21.4 parts by mass of nickel powder NI123J manufactured by Fukuda Kinzoku Hakuhoon Co., Ltd. and 1.1 parts by mass of nickel powder NI123 from Inc. were d50 of 7.0 µm, and d85 was 11.0 µm.

[Creation of Particle Dispersion Conductive Adhesive Composition J]

Nickel powder NI123J (d50: 6.3 micrometers, d85: 10.0 micrometers, tap density: 4.3 g / cm <3>, NIK Corporation made by Fukuda Kinzoku Hakuko Co., Ltd.) with respect to 100 mass parts (45 mass parts of solid content) of the said acrylic adhesive composition 2 was carried out. 22.5 parts by mass of a smoothing treatment) and 2 parts by mass of a crosslinking agent Bannock NC40 (isocyanate crosslinking agent made by DIC, 40 mass% of solid content) were mixed, and the solid content concentration was adjusted to 47 mass% with ethyl acetate, and the mixture was stirred for 10 minutes. It mixed and created particle-dispersion type conductive adhesive J.

[Creation of Particle Dispersion Conductive Adhesive Composition K]

22.5 parts by mass of nickel powder NI123 (d50: 10.7, d85: 25.0 µm) manufactured by Inc., 25 parts by mass of ethyl acetate, and a crosslinking agent Bannock NC40 (manufactured by DIC Corporation) based on 100 parts by mass of the acrylic adhesive composition 1 (45 parts by mass of solid content). 2 parts by mass of isocyanate-based crosslinking agent) were blended, the solid content concentration was adjusted to 47 mass% with ethyl acetate, mixed for 10 minutes with a dispersion stirrer, and a particle dispersion conductive adhesive K was prepared.

[Creation of Particle Dispersion Conductive Adhesive Composition L]

22.5 parts by mass of copper powder CU-HWQ 1.5 µm (d50: 1.7, d85: 3.0 µm) manufactured by Fukuda Kinzoku Hakuhoon Co., Ltd., based on 100 parts by mass of the acrylic pressure sensitive adhesive composition 1 (45 parts by mass of solid content), 25 parts by mass of ethyl acetate, 2 mass parts of crosslinking agent Bannock NC40 (isocyanate type crosslinking agent made by DIC Corporation) was mix | blended, solid content concentration was adjusted to 47 mass% with ethyl acetate, it mixed with the dispersion stirrer for 10 minutes, and the particle | grain dispersion type conductive adhesive L was created.

(Example 1)

[Creation of Conductive Adhesive Sheet]

After coating the particle-dispersion conductive adhesive composition A with a comma coater on the release film "PET38x1 A3" made by Nippon Corporation so that the thickness of the adhesive layer after drying became 10 micrometers, it dried in 80 degreeC dryer for 2 minutes, and then thickness 9 After bonding together on both surfaces of the micrometer electrolytic copper foil (CF-T9FZ-SV, the product made by Fukuda Kinzoku Hakukun Co., Ltd.), it cured at 40 degreeC for 48 hours and created the electroconductive adhesive sheet of Example 1.

(Example 2)

The electroconductive adhesive sheet of Example 2 was created like Example 1 except having made thickness of the adhesive layer after drying into 8 micrometers instead of 10 micrometers.

(Example 3)

The electrically conductive adhesive sheet of Example 3 was created like Example 1 except having set the thickness of the adhesive layer after drying to 12 micrometers instead of 10 micrometers.

(Example 4)

The electroconductive adhesive sheet of Example 4 was created like Example 1 except having used the particle-dispersed conductive adhesive composition B instead of the particle-dispersed conductive adhesive composition A.

(Example 5)

The conductive adhesive sheet of Example 5 was created similarly to Example 1 except having used the particle-dispersing conductive adhesive composition C instead of the particle-dispersing conductive adhesive composition A.

(Example 6)

After coating the particle-dispersion conductive adhesive composition A with a comma coater on the release film "PET38x1 A3" made by Nippon Corporation so that the thickness of the adhesive layer after drying became 10 micrometers, it dried in 80 degreeC dryer for 2 minutes, and then thickness 9 After bonding to the one side (harmonic-treated surface side) of micrometer electrolytic copper foil (CF-T9FZ-SV, the product made by Fukuda Kinzoku Hakukun Co., Ltd.), it cured for 48 hours at 40 degreeC, and created the electroconductive adhesive sheet of Example 6.

(Example 7)

The conductive adhesive sheet of Example 7 was created like Example 1 except having used the particle-dispersion type conductive adhesive composition D instead of the particle-dispersion type conductive adhesive composition A.

(Example 8)

A conductive adhesive sheet of Example 8 was prepared in the same manner as in Example 1 except that the particle dispersed conductive adhesive composition E was used instead of the particle dispersed conductive adhesive composition A.

(Example 9)

The conductive adhesive sheet of Example 9 was created similarly to Example 1 except having used the particle-dispersed conductive adhesive composition F instead of the particle-dispersed conductive adhesive composition A.

(Example 10)

The conductive adhesive sheet of Example 10 was created in the same manner as in Example 1 except that the particle dispersed conductive pressure-sensitive adhesive composition G was used instead of the particle dispersed conductive pressure-sensitive adhesive composition A.

(Example 11)

The electroconductive adhesive sheet of Example 11 was created like Example 1 except having used the particle-dispersion type conductive adhesive composition H instead of the particle | grain dispersion type conductive adhesive composition A.

(Example 12)

Instead of the particle-dispersed conductive adhesive composition A, a particle-dispersed conductive adhesive composition J was used, and instead of a 9 µm-thick electrolytic copper foil (CF-T9FZ-SV, manufactured by Fukuda Kinzoku Hakuhoon Co., Ltd.), 8 µm thick rolled copper foil ( Conductive adhesive sheet of Example 12 was created in the same manner as in Example 1 except that TCU-H-8-RT, manufactured by Nihon Seihaku Co., Ltd.) was used.

(Comparative Example 1)

The conductive adhesive sheet of Comparative Example 1 was prepared in the same manner as in Example 1 except that the particle dispersed conductive pressure-sensitive adhesive composition K was used instead of the particle dispersed conductive pressure-sensitive adhesive composition A.

(Comparative Example 2)

A conductive adhesive sheet of Comparative Example 2 was prepared in the same manner as in Example 1 except that the particle dispersed conductive pressure-sensitive adhesive composition L was used instead of the particle dispersed conductive pressure-sensitive adhesive composition A.

(Comparative Example 3)

The conductive adhesive sheet of Comparative Example 3 was prepared in the same manner as in Comparative Example 1 except that the thickness of the pressure-sensitive adhesive layer after drying was 30 μm instead of 10 μm.

(Comparative Example 4)

An attempt was made to produce the conductive adhesive sheet of Comparative Example 4 in the same manner as in Example 1 except that the thickness of the adhesive layer after drying was set to 5 µm, but the coating stripes were severe and a sample could not be prepared.

(Comparative Example 5)

Conductive adhesive sheet of Comparative Example 5 was created in the same manner as in Example 1 except that the thickness of the adhesive layer after drying was set to 14 μm.

(evaluation)

The adhesive sheet thickness, electroconductivity, adhesive force, and productivity were evaluated about the electroconductive adhesive sheet produced in Examples 1-12 and Comparative Examples 1-3.

[Thickness (adhesive sheet)]

The thickness of the adhesive sheet was measured with the thickness meter "TH-102" made from Tester Industries, Inc ..

In the case of a double-sided adhesive sheet, the adhesive sheet thickness was 40 micrometers or less as a pass. In the case of single side | surface, 30 micrometers or less were made the pass.

[Thickness (Adhesive Layer)]

A sample in which PET 25 μm (S25 manufactured by Unichika Co., Ltd.) was placed on the pressure-sensitive adhesive layer on the release film formed in the same manner as in the examples and the comparative example was prepared, and the thickness of the sample was measured using a thickness gauge "TH-102" manufactured by Tester Sanke. Was measured, and the thickness of the adhesive layer was obtained by removing the thickness of the peeling film and PET contacted.

[Adhesiveness]

A 20-kg-width conductive adhesive sheet sample was subjected to a 2.0 kg roller one reciprocating pressure patch on a stainless steel plate (hereinafter referred to as a stainless steel plate) subjected to hairline polishing with 360-degree water-resistant abrasive paper under an environment of 23 ° C. 60% RH. After standing for 1 hour at, a 180 degree peeling adhesive force was measured with a tensile tester (Tensilon RTA-100, manufactured by A & D Corporation) at a tensile rate of 300 mm / min at room temperature. In addition, the double-sided adhesive sheet was made to contact PET 25 micrometers (S25 by Unichika Co., Ltd.) on the opposite side to the measurement surface, and was measured.

[Resistance value]

One side of the adhesive sheet of 30 mm width x 30 mm width is affixed on the brass electrode of 25 mm x 25 mm. 30 mm x 80 mm copper foil (35 micrometers in thickness) is affixed on the other surface of a test piece. The terminal is connected to the brass electrode and the copper foil while applying a load of surface pressure of 20 N from the brass electrode, in a milliohm meter (manufactured by EN Cairo Corp.) under an environment of 50% RH at 23 ° C. The resistance value when the electric current of 10 mA was passed was measured.

The case where it was 500 m (ohm) or less was made into the pass.

[Productivity (coating stripe)]

The particle | grain dispersion | distribution type conductive adhesive composition was coated by the comma coater at the speed | rate of 20 m / min, and the stripe of the adhesive coating surface was evaluated. Moreover, the temperature was 23 degreeC.

(Double-circle): The stripe of the adhesive coating surface was not recognized at all.

(Circle): Although the streak of the adhesive coating surface was confirmed slightly, there was no problem practically (the difference of adhesive force is less than 10%)

X: Many streaks generate | occur | produced on the adhesive coating surface, and there existed a problem practically (the difference of adhesive force is 10% or more).

××: The entirety became a stripe shape on the pressure-sensitive adhesive coating surface and could not be produced

Productivity (Sedimentation)

The particle-dispersion conductive adhesive composition was left in the glass bottle to evaluate the sedimentation of the conductive particles. The temperature was 23 ° C.

(Double-circle): There was no sedimentation of electroconductive particle after 2 hours of standing still.

(Circle): There was no sedimentation of electroconductive particle even after 1 hour stationary.

×: Sedimentation occurred in less than 1 hour

[Particle size]

The particle diameter of electroconductive particle was measured with the laser diffraction type particle size distribution analyzer SALD-3000 made from Shimadzu Corporation, using isopropanol as a dispersion medium.

[Viscosity]

The viscosity of the particle | grain dispersion | distribution type electroconductive adhesive composition was measured with the B-type viscometer by Tokisan Tsuyoshi. Measurement conditions were measured under conditions of 12 RPM using a NO.3 rotor.

[Table 1]

[Table 2]

[Table 3]

As apparent from the above table, the pressure-sensitive adhesive sheets of Examples 1 to 12 of the present invention had good adhesiveness and conductivity even though they were thin, hardly caused coating streaks and sedimentation, and were excellent in productivity. On the other hand, the adhesive sheets of Comparative Examples 1-5 did not have these electroconductivity and productivity.

Claims (5)

A thin adhesive sheet having a total thickness of 40 μm or less,
It has a conductive base material and the conductive adhesive layer containing electroconductive particle, The particle diameter d50 of the said electroconductive particle is 4-12 micrometers, d85 is 6-15 micrometers, The thickness of the said adhesive layer is 6-12 micrometers, It is characterized by the above-mentioned. Electroconductive thin adhesive sheet made into. The method of claim 1,
The electroconductive thin adhesive sheet whose content of electroconductive particle in the said electroconductive adhesive layer is 10-65 mass%. 3. The method according to claim 1 or 2,
The electroconductive thin adhesive sheet whose particle diameter d50 of the said electroconductive particle is 50 to 150% of the thickness of the said adhesive layer, and d85 is 80 to 200% of the thickness of the said adhesive layer. 4. The method according to any one of claims 1 to 3,
The electroconductive thin adhesive sheet whose said electroconductive base material is metal foil. 5. The method according to any one of claims 1 to 4,
The conductive thin pressure-sensitive adhesive sheet, wherein the conductive pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer made of an acrylic pressure-sensitive adhesive composition containing an acrylic copolymer.

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