KR101534644B1 - Electroconductive thin adhesive sheet - Google Patents

Abstract

Disclosure of the Invention An object of the present invention is to provide a conductive thin type pressure-sensitive adhesive sheet having good adhesiveness, conductivity, and excellent productivity even if it is thin.
In order to solve this problem, a thin pressure sensitive adhesive sheet having a total thickness of 40 탆 or less has a conductive base material and a conductive pressure-sensitive adhesive layer containing conductive particles, wherein the conductive particles have a particle diameter d50 of 4 to 12 탆, 6 to 15 占 퐉 and the thickness of the pressure-sensitive adhesive layer is 6 to 12 占 퐉. Thus, it is possible to achieve a good productivity, good conductivity and conductivity while being thin.

Description

[0001] ELECTROCONDUCTIVE THIN ADHESIVE SHEET [0002]

The present invention relates to a conductive thin sheet having a conductive base material and a pressure-sensitive adhesive layer containing conductive particles.

Because the conductive adhesive sheet is easy to handle, the conductive adhesive sheet is useful for shielding unnecessary leakage electromagnetic waves radiated from electric or electronic devices, for shielding harmful spatial electromagnetic waves generated from other electric or electronic devices, for grounding for preventing static electricity, etc. As the electric and electronic devices have been downsized and thinned in recent years, the conductive pressure sensitive adhesive sheets used for these devices are also required to be thin.

As a thin conductive adhesive sheet, there is disclosed a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer composed of a conductive adhesive agent in which conductive fillers are dispersed in a viscous substance on a conductive substrate (see Patent Documents 1 and 2). Although these pressure-sensitive adhesive sheets are disclosed to have favorable conductivity and adhesiveness, in the case of a very thin pressure-sensitive adhesive sheet in response to recent demand for further thinning, improvement in conductivity and adhesion More is required. In addition, when the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer containing the conductive filler is made extremely thin, the pressure-sensitive adhesive layer tends to have coating streaks, so that the desired productivity can not be obtained.

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

A problem to be solved by the present invention is to provide a conductive thin type pressure-sensitive adhesive sheet having good adhesiveness, conductivity, and excellent productivity even if it is thin.

In the present invention, a thin pressure-sensitive adhesive sheet having a total thickness of 40 占 퐉 or less has a conductive base material and a conductive pressure-sensitive adhesive layer containing conductive particles, wherein the conductive particles have a particle diameter d50 of 4 to 12 占 퐉, 15 탆 and the thickness of the pressure-sensitive adhesive layer is 6 to 12 탆, it is possible to achieve a favorable productivity with a thin shape, good adhesiveness and conductivity, .

INDUSTRIAL APPLICABILITY The conductive thin type adhesive sheet of the present invention is excellent in adhesiveness and conductivity to an adherend while having an extremely thin shape and has a favorable productivity and therefore can be used for shielding electromagnetic waves used in electric and electronic equipment, And is useful for shielding harmful spatial electromagnetic waves and for fixing the ground for preventing static electricity. Particularly, thinning is progressing and can be suitably applied to portable electronic devices in which the volume limitation in the casing is strict.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing an example of a configuration example of the conductive thin-type adhesive sheet of the present invention. Fig.
2 is a view showing an example of a configuration example of the conductive thin-type adhesive sheet of the present invention.

The conductive pressure-sensitive adhesive sheet of the present invention is a thin pressure-sensitive adhesive sheet having a total thickness of 40 탆 or less, which comprises a conductive base material and a conductive pressure-sensitive adhesive layer containing conductive particles, wherein the conductive particles have a particle diameter d50 of 4 to 12 탆, Is 6 to 15 占 퐉 and the thickness of the pressure-sensitive adhesive layer is 6 to 12 占 퐉.

Hereinafter, the conductive pressure-sensitive adhesive sheet of the present invention will be described in more detail based on its constituent elements. The term " sheet " in the present invention means a form in which a thin layer of at least one conductive pressure-sensitive adhesive is provided on a conductive base material or a release sheet. For example, a sheet, roll, Shape (tape shape), and the like.

(Conductive particles)

The conductive particles used in the conductive pressure-sensitive adhesive sheet of the present invention have a particle diameter d50 of 4 to 12 m and a particle diameter d85 of 6 to 15 m. The d50 is more preferably 4 to 10 占 퐉, more preferably 5 to 9 占 퐉, and most preferably 6 to 8 占 퐉. Further, d85 is more preferably 6.5 to 14 占 퐉, more preferably 7 to 13 占 퐉, and most preferably 8 to 11 占 퐉. The particle diameter d50 is a 50% cumulative value (median diameter) in the particle size distribution. The particle diameter d85 is a cumulative value of 85%. Their particle diameters are values measured by a laser analysis / scattering method. Microtrack MT3000 Ⅱ manufactured by Nikkiso Co., Ltd., and SALD-3000, a laser diffraction particle size distribution meter manufactured by Shimadzu Seisakusho Co.,

It is preferable that the particle diameter d50 of the conductive particles is 50 to 150% of the thickness of the pressure-sensitive adhesive layer and d85 is 80 to 200%. By using the conductive particles in the above range, it is easy to achieve both conductivity, adhesive property and productivity. The 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 coating on the surfaces of hollow glass beads Can be used. Among them, nickel particles, copper particles and silver particles are preferable because they are excellent in conductivity, adhesiveness and productivity. More preferably, the surface of the particles produced by the carbonyl method is coated with nickel particles having a plurality of needles in the form of needles or spheres in the form of spheres, High-pressure swirl water (swirling water) Copper powder or silver powder produced by the atomization method. Two or more kinds of these conductive particles may be mixed so that d50 and d85 fall within the above ranges. Particularly, it is preferable that a particle diameter d50 of 10 to 12 占 퐉 or more and a particle diameter of 5 to 7 占 퐉 are mixed because of excellent conductivity.

The shape of the conductive particles is preferably spherical or surface irregular. 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. The aspect ratio can be measured with a scanning electron microscope.

The tap density of the conductive particles is not particularly limited, but is preferably 2 to 7 g / cm 3 because it is difficult for the particles to precipitate or flocculate at the time of production. More preferably 3 to 6 g / cm 3, and most preferably 4 to 5 g / cm 3.

The content of the conductive particles in the conductive pressure-sensitive adhesive layer is not particularly limited, but is preferably from 10 to 65 mass%, more preferably from 20 to 50 mass%, and even more preferably from 22 to 41 mass% , And most preferably 28 to 38 mass%. By setting the content of the conductive particles within the above range, it is easy to achieve both conductivity, adhesion and productivity.

(Pressure-sensitive adhesive composition)

The conductive pressure-sensitive adhesive layer used in the conductive pressure-sensitive adhesive sheet of the present invention is formed from a pressure-sensitive adhesive composition containing the conductive particles. As the pressure-sensitive adhesive composition for forming the conductive pressure-sensitive adhesive layer, a pressure-sensitive adhesive composition used for an ordinary pressure-sensitive adhesive sheet can be used. 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 and silicone pressure sensitive adhesives. (Meth) acrylic pressure-sensitive adhesive composition in which an acrylic copolymer made from a co-polymer is used as a base polymer and, if necessary, an additive such as a pressure-sensitive adhesive resin or a crosslinking agent is blended therein can be preferably used from the viewpoint of weather resistance and heat resistance.

As the acrylic copolymer, an acrylic copolymer having a (meth) acrylate monomer having a carbon number of 1 to 14 as a main monomer component can be preferably used. As the (meth) acrylate having a carbon number of 1 to 14, for example, methyl (Meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (Meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, cyclohexyl (meth) acrylate and 2-ethylhexyl Species or two or more species are used. Among them, (meth) acrylates having an alkyl group of 4 to 12 carbon atoms are preferable, and (meth) acrylates having a straight-chain or branched structure of 4 to 9 carbon atoms are more preferable. Of these, n-butyl acrylate and 2-ethylhexyl acrylate are preferably used, and these may be used alone or in combination.

The content of the (meth) acrylate having 1 to 14 carbon atoms in the acrylic copolymer is preferably 80 to 98.5 mass%, more preferably 90 to 98.5 mass%, of the monomer components constituting the acrylic copolymer.

The acrylic copolymer used in the present invention is also preferably copolymerized with a high polar vinyl monomer. Examples of the high polar vinyl monomer include vinyl monomers having a carboxyl group, vinyl monomers having a hydroxyl group, vinyl monomers having an amide group, and the like , One or more of these may be used. Among them, the carboxyl group-containing monomer can be suitably used since it is easy to adjust the adhesiveness of the pressure-sensitive adhesive to a favorable range.

As the vinyl monomer having a carboxyl group, acrylic acid, methacrylic acid, itaconic acid, maleic acid, (meth) acrylic acid dimer, crotonic acid, ethylene oxide modified succinic acid acrylate and the like can be used. Among them, acrylic acid is used as a copolymerization component .

When a vinyl monomer having a carboxyl group is used, the content thereof is preferably 0.2 to 15% by mass, more preferably 0.4 to 10% by mass, and more preferably 0.5 to 6% by mass in the monomer component constituting the acrylic copolymer Is more preferable. By the content within the above range, it is easy to adjust the adhesiveness of the pressure-sensitive adhesive to a favorable range.

Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (Meth) acrylate having a hydroxyl group such as acrylate.

Examples of the monomer having an amide group include N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide and N, N-dimethylacrylamide.

Other high polar vinyl monomers include sulfonic acid group-containing monomers such as vinyl acetate, ethylene oxide modified succinic acid acrylate and 2-acrylamide-2-methylpropane sulfonic acid, 2-methoxyethyl (meth) And terminal alkoxy-modified (meth) acrylates such as ethyl (meth) acrylate.

The content of the high polar vinyl monomer is preferably 0.2 to 15% by mass, more preferably 0.4 to 10% by mass, still more preferably 0.5 to 6% by mass in the monomer component constituting the acrylic copolymer Do. By the content within the above range, it is easy to adjust the adhesiveness of the pressure-sensitive adhesive to a favorable range.

The acrylic copolymer can be obtained by copolymerization by a known method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method, etc. However, from the viewpoint of production cost and productivity, And the like. The average molecular weight of the acrylic copolymer is preferably from 300,000 to 150,000, and more preferably from 500,000 to 120,000.

(Gel fraction of the pressure-sensitive adhesive)

The (meth) acrylic pressure-sensitive adhesive used in the conductive pressure-sensitive adhesive sheet of the present invention preferably forms a three-dimensional crosslinked structure for improving the cohesive force. As an index of the formation of the crosslinked structure, the gel fraction which appears as an insoluble matter after being immersed in toluene which is a good solvent (good solvent) for the (meth) acrylic pressure-sensitive adhesive for 24 hours is used. In this case, it is preferably 25 to 60 mass%, more preferably 30 to 40 mass%. When the gel fraction is less than 25 mass%, the cohesive force in the shear direction is insufficient. When the gel fraction is more than 60 mass%, the peel resistance is deteriorated.

The gel fraction is calculated by the following equation.

Gel fraction (mass%) = {(mass of pressure-sensitive adhesive after immersion in toluene) / (mass of pressure-sensitive adhesive before immersion in toluene)} 100

* Mass of the pressure-sensitive adhesive = (mass of the conductive pressure-sensitive adhesive sheet) - (mass of the substrate) - (mass of the conductive particle)

Examples of the crosslinking structure include known crosslinking agents such as an isocyanate crosslinking agent, an epoxy crosslinking agent, a chelating crosslinking agent, and an aziridine crosslinking agent. The kind of the cross-linking agent is preferably selected according to the functional group of the above-mentioned monomer component. The amount of the crosslinking agent to be added is not particularly limited as long as the gel fraction can be adjusted to 25 to 60% by mass.

(additive)

In order to improve the adhesive strength of the conductive pressure sensitive adhesive sheet, a tackifying resin may be further added. The adhesion-imparting resin to be added to the particle-dispersed conductive pressure-sensitive adhesive used in the present invention may be any of a rosin-based resin, a terpene-based resin, a petroleum resin such as an aliphatic (C5) , A xylylene resin, a methacrylic resin, and the like. Among them, a rosin-based resin is preferable, and a polymerized rosin-based resin is particularly preferable. The amount of the tackifier resin to be added is preferably 10 to 50 mass% with respect to 100 parts by mass of the (meth) acrylic copolymer.

Various additives may be added to the pressure-sensitive adhesive for use in the conductive pressure-sensitive adhesive sheet of the present invention, if necessary. Examples of the additive include a plasticizer, a softening agent, a metal deactivator, an antioxidant, a pigment, and a dye, and if necessary, the additive is used.

(Particle Dispersion Type Conductive Pressure-Sensitive Adhesive Composition)

Examples of the method of dispersing the conductive particles of the sticky material include a method of dispersing the sticky substance, the solvent, the conductive particles, and the additives with a dispersion stirrer. Examples of commercially available dispersion stirrers include Inoue Seisakusho Dissolver, butterfly mixer, BDM biaxial mixer, and planetary mixer. Among them, a dissolver or a butterfly mixer in which a moderate shear having a small viscosity increase of the pressure-sensitive adhesive during agitation is added is preferable.

The viscosity of the particle-dispersed electroconductive pressure-sensitive adhesive composition is not particularly limited, but is preferably 100 to 10,000 MPa · s, more preferably 500 to 8000 MPa · s, and most preferably 1000 to 3000 MPa · s. When the viscosity is low, the conductive particles are apt to be easily precipitated in a time (time). On the other hand, if the viscosity is too high, coating stripes tend to occur at the time of thin film coating. Examples of the method for adjusting the viscosity include adjusting the content and type of the solvent, and adjusting the kind and molecular weight of the viscous material. Among them, the content and type of the solvent can be easily adjusted.

The solid content of the particle-dispersed conductive pressure-sensitive adhesive composition is not particularly limited, but is preferably from 10 to 70%, more preferably from 30 to 55%, and most preferably from 43 to 50%.

(Thickness of the conductive adhesive layer)

The thickness of the adhesive layer of the conductive pressure sensitive adhesive sheet is 6 to 12 占 퐉. Preferably 7 to 11 占 퐉, and particularly preferably 8 to 10 占 퐉. Within this range, it is preferable that coating stripes are unlikely to be generated and the conductivity is excellent.

(Conductive substrate)

Examples of the conductive base used in the conductive pressure-sensitive adhesive sheet of the present invention include a metal foil base and a graphite base. Examples of the material of the metal foil include gold, silver, copper, aluminum, nickel, iron, tin and alloys thereof. Among them, an aluminum foil or a copper foil is preferable in terms of processability and cost. More preferably, the electrolytic copper foil subjected to roughening treatment is preferable because of its excellent conductivity. Examples of commercially available electrolytic copper foils include CF-T9FZ-HS-9 (9 占 퐉) and CF-T9FZ-HS-9 (9 占 퐉) manufactured by Fukuda Kinko Corporation. Examples of commercially available rolled copper foils include TCU-H-8-RT (8 탆) made by Nippon Seifuku Co., Ltd., and TPC (6 탆) made by JX Nikkosuke Kinko Corporation.

The thickness of the conductive base material is preferably 1 to 24 占 퐉, more preferably 3 to 16 占 퐉, and most preferably 6 to 12 占 퐉. Within the above-mentioned range, it is preferable because it can be thinned and excellent in workability.

(Peel liner)

In the conductive adhesive sheet of the present invention, the release liner can be laminated on the adhesive layer. The release liner is not particularly limited, and examples of the release liner include paper such as kraft paper, glaze paper and top paper, resin films such as polyethylene, polypropylene (OPP, CPP), and polyethylene terephthalate, Laminating paper, paper obtained by subjecting the paper sheet to a filling treatment with crayon polyvinyl alcohol, or the like, or one obtained by subjecting both surfaces of the paper sheet to peeling treatment such as a silicone resin can be used.

(Constitution of conductive adhesive sheet)

The conductive pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet having a conductive pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive composition containing the above-mentioned conductive particles and a conductive base, and has a total thickness of 40 탆 or less. INDUSTRIAL APPLICABILITY The conductive pressure-sensitive adhesive sheet of the present invention is an extremely thin-type structure having a total thickness of 40 占 퐉 or less which is capable of responding to the demand for thinness of portable electronic devices and the like, Productivity can be realized.

The total thickness of the conductive pressure-sensitive adhesive sheet is preferably 40 占 퐉 or less, more preferably 35 占 퐉 or less, further preferably 30 占 퐉 or less and particularly preferably 20 占 퐉 or less. Within the above range, it is possible to reduce the thickness of the pressure-sensitive adhesive sheet while securing the adhesiveness and conductivity, thereby contributing to the thinness of the portable electronic device. The total thickness of the conductive pressure-sensitive adhesive sheet is the thickness of the conductive pressure-sensitive adhesive sheet itself not including the release liner.

Figs. 1 and 2 show examples of typical configurations of the conductive pressure-sensitive adhesive sheet of the present invention. Fig. 1 is a one-sided pressure-sensitive adhesive sheet in which a conductive pressure-sensitive adhesive layer (2) is laminated on a conductive substrate (1). 2 is a double-sided pressure-sensitive adhesive sheet in which a conductive pressure-sensitive adhesive layer 2 is laminated on both surfaces of a conductive substrate 1. Fig. In these configurations, a configuration in which a release liner is provided on the surface of the pressure-sensitive adhesive layer 2 can be preferably used.

[Example]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the invention is not limited to these examples.

(Adjustment of acrylic pressure-sensitive adhesive composition)

[Preparation of acrylic pressure-sensitive adhesive composition 1]

75.0 parts by mass of n-butyl acrylate, 19.0 parts by mass of 2-ethylhexyl acrylate, 3.9 parts by volume of vinyl acetate, 2.0 parts by mass of acrylic acid, 2 parts by mass of 2-hydroxyethyl acrylate And 0.1 part by mass of 2,2'-azobisisobutylnitrile as a polymerization initiator were dissolved in 100 parts by mass of ethyl acetate, and after nitrogen replacement, the mixture was polymerized at 80 DEG C for 12 hours to obtain an acrylic copolymer having a weight average molecular weight of 60,000 . 10 parts by mass of polymerized rosin pentaerythritol ester (Pencel D-135, softening point 135 ° C, manufactured by Arakawa Chemical Industries, Ltd.), 10 parts by mass of disproportionated rosin glycerin ester (Arakawa Chemical Industries, 10 parts by mass of a thermoplastic resin (trade name: SUPERESTER A-100, softening point: 100 占 폚, manufactured by Kaku Co., Ltd.) were mixed, and the resin solid content concentration was adjusted to 45 mass% with ethyl acetate to adjust the acrylic pressure-

[Preparation of acrylic pressure-sensitive adhesive composition 2]

In a reaction vessel equipped with a cooling tube, a stirrer, a thermometer and a dropping funnel, 96.0 parts by mass of n-butyl acrylate, 0.1 part by mass of 2-hydroxyethyl acrylate, 3.9 parts by mass of acrylic acid, 0.1 part by mass of isobutylnitrile was dissolved in 100 parts by mass of ethyl acetate, and after nitrogen replacement, polymerization was carried out at 80 占 폚 for 12 hours to obtain an acrylic copolymer having a mass average molecular weight of 60,000. 10 parts by mass of polymerized rosin pentaerythritol ester (Pencel D-135, softening point 135 ° C, manufactured by Arakawa Chemical Industries, Ltd.), 10 parts by mass of disproportionated rosin glycerin ester (Arakawa Chemical Industries, 10 parts by mass of a polyester resin (trade name: Super Ester A-100, softening point: 100 占 폚, manufactured by KAKKAI CO., LTD.) And adjusting the resin solid content concentration to 45 mass% with ethyl acetate to adjust the acrylic pressure-

(Preparation of particle-dispersed conductive pressure-sensitive adhesive composition)

[Preparation of particle-dispersed conductive pressure-sensitive adhesive composition A]

(D50: 6.3 mu m, d85: 10.0 mu m, tap density: 4.3 g / cm < 3 >, Incorporated NI123) was added to 100 parts by mass (solid content: 45 parts by mass) of the acrylic pressure- And 2 parts by mass of a cross-linking agent Bar-Nok NC40 (isocyanate-based cross-linking agent of DIC Corporation, solid content 40% by mass) were mixed. The solid content concentration was adjusted to 47% by mass with ethyl acetate, And mixed to prepare a particle dispersion type conductive pressure-sensitive adhesive A.

[Preparation of particle-dispersed conductive pressure-sensitive adhesive composition B]

(D50: 6.3 mu m, d85: 10.0 mu m, tap density: 4.3 g / cm < 3 >, Incorporated NI123) was added to 100 parts by mass (solid content: 45 parts by mass) of the acrylic pressure- 13.5 parts by mass) and 2 parts by mass of a cross-linking agent Barok NC40 (isocyanate-based crosslinking agent of DIC Corporation, solids content: 40% by mass) were mixed. The solid content concentration was adjusted to 47% by mass with ethyl acetate, And mixed to prepare a particle dispersion type conductive pressure-sensitive adhesive B.

[Preparation of particle-dispersed conductive pressure-sensitive adhesive composition C]

(D50: 6.3 mu m, d85: 10.0 mu m, tap density: 4.3 g / cm < 3 >, Incorporated NI123) was added to 100 parts by mass (solid content: 45 parts by mass) of the acrylic pressure- 31.5 parts by mass), and 2 parts by mass of a cross-linking agent Barnock NC40 (isocyanate-based crosslinking agent of DIC Corporation, solid content 40% by mass) were mixed. The solid content concentration was adjusted to 47% by mass with ethyl acetate, Followed by mixing to prepare a particle dispersion type conductive pressure-sensitive adhesive C.

[Preparation of particle-dispersed conductive pressure-sensitive adhesive composition D]

(D50: 6.3 mu m, d85: 10.0 mu m, tap density: 4.3 g / cm < 3 >, Incorporated NI123) was added to 100 parts by mass (solid content: 45 parts by mass) of the acrylic pressure- 22.5 parts by mass of a cross-linking agent Bar-Nok NC40 (isocyanate-based cross-linking agent of DIC Corporation, solid content 40% by mass) were mixed and adjusted to a solid content concentration of 55% by mass, Dispersion type conductive pressure-sensitive adhesive D was prepared.

[Preparation of particle-dispersed conductive pressure-sensitive adhesive composition E]

(D50: 6.3 mu m, d85: 10.0 mu m, tap density: 4.3 g / cm < 3 >, Incorporated NI123) was added to 100 parts by mass (solid content: 45 parts by mass) of the acrylic pressure- 22.5 parts by mass of a cross-linking agent, Barok NC40 (an isocyanate crosslinking agent of DIC Corporation, solid content: 40% by mass), 2 parts by mass of a cross-linking agent, and the solid content concentration was adjusted to 40% by mass with ethyl acetate. To thereby prepare a particle dispersion type conductive pressure-sensitive adhesive E.

[Preparation of particle-dispersed conductive pressure-sensitive adhesive composition F]

(D50: 4.3 占 퐉, d85: 7.0 占 퐉, tap density: 4.8 g / cm3, ultrahigh pressure (?)) Was added to 100 parts by mass (solid content: 45 parts by mass) of the acrylic pressure- 22.5 parts by mass of a swirling water atomization micropowder) and 2 parts by mass of a cross-linking agent BARNOCK NC40 (isocyanate-based cross-linking agent of DIC Corporation, solid content: 40% by mass) were mixed. The solid content concentration was adjusted to 47% by mass with ethyl acetate, For 10 minutes to prepare a particle dispersion type conductive pressure-sensitive adhesive F.

[Preparation of particle-dispersed conductive pressure-sensitive adhesive composition G]

(D50: 10.0 mu m, d85: 13.0 mu m, tap density: 4.7 g / cm < 3 >) at 100 parts by mass (solid content: 45 parts by mass) of the acrylic pressure- 22.5 parts by mass of a swirling water atomization micropowder) and 2 parts by mass of a cross-linking agent BARNOCK NC40 (isocyanate-based cross-linking agent of DIC Corporation, solid content: 40% by mass) were mixed. The solid content concentration was adjusted to 47% by mass with ethyl acetate, For 10 minutes to prepare a particle dispersion type conductive pressure-sensitive adhesive G.

[Preparation of particle-dispersed conductive pressure-sensitive adhesive composition H]

(D50: 6.3 mu m, d85: 10.0 mu m, tap density: 4.3 g / cm < 3 >, Incorporated NI123) was added to 100 parts by mass (solid content: 45 parts by mass) of the acrylic pressure- , 1.1 parts by mass of an inorganic modified nickel NI123 (d50: 10.7, d85: 25.0 mu m) and 2 parts by mass of a crosslinking agent Barnock NC40 (isocyanate crosslinking agent of DIC Corporation, solids content: 40% by mass) , The solid content concentration was adjusted to 47% by mass with ethyl acetate, and the mixture was mixed with a dispersion stirrer for 10 minutes to prepare a particle dispersion type conductive pressure-sensitive adhesive H. Further, the d50 of the mixed metal powder of 21.4 parts by mass of nickel powder NI123J and 1.1 parts by mass of incollimated nickel powder NI123 was 7.0 mu m and the d 85 was 11.0 mu m.

[Preparation of particle-dispersed conductive pressure-sensitive adhesive composition J]

(D50: 6.3 mu m, d85: 10.0 mu m, tap density: 4.3 g / cm < 3 >, Incorporated NI123) was added to 100 parts by mass (solid content: 45 parts by mass) of the acrylic pressure- And 2 parts by mass of a cross-linking agent Bar-Nok NC40 (isocyanate-based cross-linking agent of DIC Corporation, solid content 40% by mass) were mixed. The solid content concentration was adjusted to 47% by mass with ethyl acetate, And mixed to prepare a particle dispersion type conductive adhesive agent J.

[Preparation of particle-dispersed conductive pressure-sensitive adhesive composition K]

22.5 parts by mass of nickel component NI123 (d50: 10.7, d85: 25.0 탆) manufactured by Incorporated, 25 parts by mass of ethyl acetate, 25 parts by mass of a crosslinking agent Barnock NC40 By weight of isocyanate-based cross-linking agent) were mixed. The solid content concentration was adjusted to 47% by mass with ethyl acetate and mixed by a dispersion stirrer for 10 minutes to prepare a particle dispersion type conductive pressure-sensitive adhesive K.

[Preparation of particle-dispersed conductive pressure-sensitive adhesive composition L]

22.5 parts by mass of copper powder CU-HWQ 1.5 占 퐉 (d50: 1.7, d85: 3.0 占 퐉), 25 parts by mass of ethyl acetate, and 50 parts by mass of acrylic acid were added to 100 parts by mass (solid content: 45 parts by mass) 2 parts by mass of a cross-linking agent Bar-Nok NC40 (an isocyanate-based cross-linking agent manufactured by DIC Corporation) was mixed. The solid content concentration was adjusted to 47% by mass with ethyl acetate and mixed by a dispersion stirrer for 10 minutes to prepare a particle dispersion type conductive pressure-

(Example 1)

[Preparation of conductive pressure-sensitive adhesive sheet]

The particle-dispersed conductive pressure-sensitive adhesive composition A was coated on a release film " PET38 x 1 A3 " manufactured by Nippon Paper Industries Co., Ltd. by a comma coater so that the thickness of the pressure-sensitive adhesive layer after drying was 10 탆, dried in a dryer at 80 캜 for 2 minutes, (CF-T9FZ-SV, manufactured by Fukuda Kinko Co., Ltd.) and then cured at 40 占 폚 for 48 hours to prepare a conductive pressure-sensitive adhesive sheet of Example 1.

(Example 2)

The conductive pressure-sensitive adhesive sheet of Example 2 was prepared in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer after drying was changed to 8 占 퐉 instead of 10 占 퐉.

(Example 3)

The conductive adhesive sheet of Example 3 was prepared in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer after drying was changed to 12 占 퐉 instead of 10 占 퐉.

(Example 4)

A conductive pressure-sensitive adhesive sheet of Example 4 was prepared in the same manner as in Example 1 except that the particle-dispersed conductive pressure-sensitive adhesive composition B was used in place of the particle-dispersed conductive pressure-sensitive adhesive composition A.

(Example 5)

A conductive pressure-sensitive adhesive sheet of Example 5 was prepared in the same manner as in Example 1 except that the particle-dispersed conductive pressure-sensitive adhesive composition C was used in place of the particle-dispersed conductive pressure-sensitive adhesive composition A.

(Example 6)

The particle-dispersed conductive pressure-sensitive adhesive composition A was coated on a release film " PET38 x 1 A3 " manufactured by Nippon Paper Industries Co., Ltd. by a comma coater so that the thickness of the pressure-sensitive adhesive layer after drying was 10 탆, dried in a dryer at 80 캜 for 2 minutes, (The roughened surface side) of an electrolytic copper foil (CF-T9FZ-SV, Fukuda Kinzoku Hakuhuno Teacher Co., Ltd.) having a thickness of 50 mu m and then cured at 40 DEG C for 48 hours to prepare a conductive adhesive sheet of Example 6.

(Example 7)

A conductive pressure-sensitive adhesive sheet of Example 7 was prepared in the same manner as in Example 1 except that the particle-dispersed conductive pressure-sensitive adhesive composition D was used in place of the particle-dispersed conductive pressure-sensitive 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 pressure-sensitive adhesive composition E was used in place of the particle-dispersed conductive pressure-sensitive adhesive composition A.

(Example 9)

A conductive pressure-sensitive adhesive sheet of Example 9 was prepared in the same manner as in Example 1 except that the particle-dispersed conductive pressure-sensitive adhesive composition F was used in place of the particle-dispersed conductive pressure-sensitive adhesive composition A.

(Example 10)

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

(Example 11)

The conductive pressure-sensitive adhesive sheet of Example 11 was prepared in the same manner as in Example 1 except that the particle-dispersed conductive pressure-sensitive adhesive composition H was used instead of the particle-dispersed conductive pressure-sensitive adhesive composition A.

(Example 12)

Instead of the particle-dispersed conductive pressure-sensitive adhesive composition A, a particle-dispersed conductive pressure-sensitive adhesive composition J was used. A conductive copper foil (CF-T9FZ-SV, Fukuda Kinko Co., TCU-H-8-RT, manufactured by Nihon Seihaku Co., Ltd.) was used as the conductive adhesive sheet.

(Comparative Example 1)

A conductive pressure-sensitive 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 in place of the particle-dispersed conductive pressure-sensitive adhesive composition A.

(Comparative Example 2)

A conductive pressure-sensitive 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 in place of the particle-dispersed conductive pressure-sensitive adhesive composition A.

(Comparative Example 3)

The conductive pressure-sensitive 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 changed to 30 占 퐉 instead of 10 占 퐉.

(Comparative Example 4)

The conductive adhesive sheet of Comparative Example 4 was tried to be formed in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer after drying was changed to 5 占 퐉.

(Comparative Example 5)

The conductive pressure-sensitive adhesive sheet of Comparative Example 5 was prepared in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer after drying was changed to 14 占 퐉.

(evaluation)

The conductive adhesive sheets prepared in Examples 1 to 12 and Comparative Examples 1 to 3 were evaluated for adhesive sheet thickness, conductivity, adhesive force and productivity.

[Thickness (adhesive sheet)]

The thickness of the pressure-sensitive adhesive sheet was measured with a TH-102 thickness meter manufactured by Testers.

In the case of the double-sided pressure-sensitive adhesive sheet, the thickness of the pressure-sensitive adhesive sheet was set to 40 μm or less. In the case of a single surface, the thickness of 30 μm or less is acceptable.

[Thickness (pressure-sensitive adhesive layer)]

A sample of PET 25 mu m (S25, manufactured by Unichica Corporation) was bonded to the pressure-sensitive adhesive layer on the release film formed in the same manner as in the above Examples and Comparative Examples, and the thickness of the sample And the thickness of the release film and the bonded PET was subtracted to obtain the thickness of the pressure-sensitive adhesive layer.

[Adhesion]

A 20 mm wide conductive adhesive sheet sample was applied to a stainless steel plate (hereinafter referred to as a stainless steel plate) which had been subjected to hairline polishing with 360 number of domestic abrasive paper to a 2.0 kg roller 1 reciprocating pressure applying portion in an environment of 23 캜 and 60% RH, , The adhesive strength at 180 degrees peel strength was measured at a tensile rate of 300 mm / min at room temperature using a tensile tester (Tensilon RTA-100, manufactured by A & D Co., Ltd.). In the double-faced pressure-sensitive adhesive sheet, PET 25 μm (S25, manufactured by Unichica Corporation) was bonded to the opposite side of the measurement side.

[Resistance value]

One surface of a 30 mm wide x 30 mm wide pressure sensitive adhesive sheet is affixed to a brass electrode of 25 mm x 25 mm. A 30 mm x 80 mm copper foil (35 μm thick) is attached to the other side of the test piece. A brass electrode and a copper foil were connected to each other while applying a load of 20 N from a brass electrode, and the electrode was connected to a copper foil by means of a milliohmmeter (manufactured by ENFAC CO., LTD.) Under an environment of 23 ° C. and 50% And the resistance value when a current of 10 was passed was measured.

The case of 500 m? Or less was regarded as acceptable.

[Productivity (coated stripes)]

The particle dispersion type conductive pressure-sensitive adhesive composition was applied with a comma coater at a speed of 20 m / min to evaluate the striations on the coated surface of the pressure-sensitive adhesive. The temperature was 23 占 폚.

◎: Stripes on the coated surface of the pressure-sensitive adhesive were not confirmed at all

○: Stripes on the coated surface of the pressure-sensitive adhesive were slightly observed, but there was no problem in practical use (difference in the adhesive strength was less than 10%)

X: Many streaks occurred on the coated surface of the pressure-sensitive adhesive, causing a problem in practical use (difference in adhesive force between 10%

××: The entire surface of the pressure-sensitive adhesive coated surface has a striped shape, which could not be produced

[Productivity (sedimentation)]

The particle-dispersed conductive pressure-sensitive adhesive composition was placed in a glass bottle to evaluate sedimentation of the conductive particles. The temperature was 23 占 폚.

◎: There was no settling of conductive particles even after 2 hours of standing

○: No sedimentation of conductive particles even after 1 hour of standing

×: Settling occurred in less than 1 hour

[Particle size]

The particle diameter of the conductive particles was measured using a laser diffraction particle size distribution analyzer SALD-3000 manufactured by Shimadzu Seisakusho Co., Ltd., using isopropanol as a dispersion medium.

[Viscosity]

The viscosity of the particle-dispersed conductive pressure-sensitive adhesive composition was measured with a B-type viscometer manufactured by Toki Sangyo Co., Ltd. Measurement conditions were measured under the condition of 12 RPM using a NO.3 rotor.

[Table 1]

[Table 2]

[Table 3]

As is evident from the above table, the pressure-sensitive adhesive sheets of Examples 1 to 12 of the present invention had good adhesiveness and conductivity even with a thin shape, were hard to cause coating streaking or sedimentation, and were excellent in productivity. On the other hand, the pressure-sensitive adhesive sheets of Comparative Examples 1 to 5 did not have both conductivity and productivity.

Claims (5)

As a thin pressure sensitive adhesive sheet having a total thickness of 40 탆 or less,
Wherein the conductive particles have a particle diameter d50 of 4 to 12 占 퐉, a d85 of 6 to 15 占 퐉, a thickness of the pressure-sensitive adhesive layer of 6 to 12 占 퐉, Wherein the conductive particles have a tap density of 2 to 7 g / cm ³ and the pressure sensitive adhesive used in the conductive pressure sensitive adhesive layer is a (meth) acrylic pressure sensitive adhesive having a gel fraction of 25 to 60 mass% Sheet.
Gel fraction (mass%) = {(mass of pressure-sensitive adhesive after immersion in toluene for 24 hours) / (mass of pressure-sensitive adhesive before immersion in toluene)} 100
(Mass of conductive adhesive sheet) - (mass of base) - (mass of conductive particle) The method according to claim 1,
Wherein the content of the conductive particles in the conductive pressure-sensitive adhesive layer is 10 to 65 mass%. 3. The method according to claim 1 or 2,
Wherein the conductive particles have a particle size d50 of 50 to 150% of the thickness of the pressure-sensitive adhesive layer and d85 is 80 to 200% of the thickness of the pressure-sensitive adhesive layer. 3. The method according to claim 1 or 2,
Wherein the conductive base material is a metal foil. 3. The method according to claim 1 or 2,
Wherein the conductive pressure-sensitive adhesive layer comprises an acrylic pressure-sensitive adhesive composition containing an acrylic copolymer.

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