TW201446936A - Conductive adhesive sheet, method for manufacturing same and electronic terminal obtained by using same - Google Patents

Abstract

A conductive adhesive sheet provided with a conductive adhesive layer at least on one surface of a conductive base material, characterized in that the conductive base material is prepared by subjecting a wet-type polyester-based nonwoven fabric base material to a plating treatment including an electroless plating treatment, and the conductive adhesive layer contains conductive particles in an amount of 3-50 mass% relative to the whole conductive adhesive layer.

Description

Conductive adhesive sheet, manufacturing method thereof and electronic terminal machine obtained by using the same

The present invention relates to a conductive adhesive sheet which can be used in the manufacture of an electronic device such as a portable electronic terminal.

In recent years, with the miniaturization, thinning, and high performance of electronic equipment such as communication equipment, high density has progressed. In the manufacture of the aforementioned electronic device, a conductive adhesive sheet is often used in order to shield electromagnetic waves that may be generated from an electronic device or to impart antistatic properties to an arbitrary portion. For the conductive adhesive sheet, for example, an adhesive sheet having a conductive adhesive layer containing a conductive filler on a conductive substrate made of a metal foil is known (see, for example, Patent Documents 1 and 2).

As described above, the conductive adhesive sheet using the metal foil is insufficient in flexibility. When there is a slight difference in the surface of the adherend, the height difference portion cannot be followed, and the interface between the adherend and the adhesive layer is formed. The situation of the gap.

On the other hand, in the industry, when the conductive adhesive sheet is attached to the wrong position of the adherend, it is required to be reworkable to the extent that it can be easily peeled off immediately after attachment. However, the conductive adhesive sheet is often insufficient in terms of the above-described reworkability, and may not be reused and reattached. As described above, there is no conductive adhesive sheet having flexibility and reworkability to the extent that it can sufficiently shield electromagnetic waves and the like, and can follow the height difference portion of the adherend.

[PRIOR ART DOCUMENT] [Patent Document 1] JP-A-2004-263030 (Patent Document 2) JP-A-2009-79127

(The subject to be solved by the invention)

An object of the present invention is to provide a conductive adhesive sheet which has both electrical conductivity capable of sufficiently shielding electromagnetic waves and the like, flexibility to follow the height difference portion of the adherend, and the like. (method of solving the problem)

In the present invention, the above problem is solved by using the following conductive adhesive sheet. That is, a conductive adhesive sheet having a conductive adhesive layer on at least one side of a conductive substrate, wherein the conductive substrate is coated with a non-woven fabric for a wet polyester-based nonwoven fabric. In the conductive adhesive layer, the conductive adhesive layer contains 3% by mass to 50% by mass of the conductive particles in the entire conductive adhesive layer. (Effect of the invention)

In the conductive adhesive sheet of the present invention, the flexibility and the reworkability can be achieved to the extent that the electrical conductivity of the electromagnetic wave or the like can be sufficiently shielded, and the level difference between the fine unevenness and the like which is possessed by the adherend can be achieved. Since the body has an excellent adhesive force, it can be suitably used as, for example, an electromagnetic wave shielding sheet used for manufacturing electronic equipment or the like, and an adhesive sheet for preventing grounding for electrostatic charging.

The conductive adhesive sheet of the present invention has a conductive adhesive layer on at least one side of the conductive substrate, and the conductive substrate is coated with a non-electrolytic plating on the wet polyester nonwoven substrate. In the conductive adhesive layer, the conductive adhesive layer contains 3 to 50% by mass of the conductive particles in the entire conductive adhesive layer.

The term "sheet" as used in the present invention means a form having at least one layer of a conductive adhesive layer on at least one side of a conductive substrate. Further, the sheet includes, for example, all of the product forms such as a single sheet, a roll, a thin plate, and a belt (tape).

The conductive adhesive sheet of the present invention has a structure in which a single layer or a plurality of layers of the above-mentioned conductive adhesive layer are provided on one surface of a conductive substrate, and each of the conductive substrates has a single layer or a plurality of layers of the above-mentioned conductive materials. The structure of the adhesive layer. The conductive adhesive sheet of the present invention may have other layers than the conductive substrate and the conductive adhesive layer as needed.

The conductive adhesive sheet preferably has a total thickness of 100 μm or less, and preferably has a total thickness of 60 μm or less. When the total thickness is 40 μm or less, it can maintain excellent flexibility, conductivity, and adhesion, and can contribute to electronic equipment and the like. It is thinner and therefore ideal. Further, the lower limit of the total thickness of the conductive adhesive sheet is preferably 5 μm or more. Moreover, the said total thickness means the thickness of the electroconductive adhesive sheet which does not contain a peeling film itself.

The conductive substrate constituting the conductive adhesive sheet of the present invention can be obtained by applying a plating treatment including a non-electrolytic plating treatment to a wet polyester nonwoven fabric substrate.

The conductive substrate is preferably used in a thickness of 6 μm to 50 μm, and more preferably in a thickness of 10 μm to 30 μm.

The conductive substrate preferably has a tensile strength in the MD (flow) direction of 3N/20 mm to 35 N/20 mm, preferably 5 N/20 mm to 30 N/20 mm, and 10 N/20 mm to 27 N/20 mm. good. Further, the conductive substrate is preferably a tensile strength in the TD (wide) direction of 0.5 N/20 mm to 35 N/20 mm, more preferably 3 N/20 mm to 30 N/20 mm, and 10 N/20 mm to 27 N/20 mm. Better yet. By using a conductive substrate having a tensile strength in the MD (flow) direction and the TD (width) direction in the above range, it is less likely to cause breakage of the conductive adhesive sheet during rework (peeling), and excellent reworkability can be maintained. Further, a conductive adhesive sheet having good adhesion between the conductive substrate and the conductive adhesive layer can be obtained. When the conductive substrate has a tensile strength in the MD direction/tensile strength in the TD direction of 0.7 to 1.3, the conductive adhesive sheet is less likely to be broken during rework (peeling), and excellent reworkability can be maintained. Therefore, it is ideal. Further, the tensile strength is measured by stretching at a speed of 300 mm/min in accordance with JIS Z0237-2010.

Further, it is preferable that the conductive substrate has a surface resistance □ (x-axis direction, y-axis direction) of 0.5 Ω/25 mm×25 mm or less, and has a surface resistance of 0.1 Ω/25 mm×25 mm or less (x-axis direction). , the y-axis direction is better, and the surface resistance □ (x-axis direction, y-axis direction) of 0.05 Ω / 25 mm × 25 mm or less is more preferable, by using a surface resistance of 0.01 Ω / 25 mm × 25 mm or less □ ( X, y) is particularly desirable in imparting better electrical conductivity. Further, it is preferable that the conductive substrate has a vertical surface resistance □ (z-axis direction) of 0.1 Ω / 25 mm × 25 mm or less, and a vertical surface resistance □ (z-axis direction) of 0.05 Ω / 25 mm × 25 mm or less. More preferably, it is preferably a vertical surface resistance □ (z-axis direction) of 0.03 Ω / 25 mm × 25 mm or less, and a vertical surface resistance □ (z-axis direction) of 0.01 Ω / 25 mm × 25 mm or less is used. It is particularly desirable for excellent electrical conductivity. Further, the measurement methods of the surface resistance □ (x-axis direction, y-axis direction) and vertical surface resistance □ (z-axis direction) are measured by the method described in the examples.

When manufacturing the above-mentioned conductive substrate, a wet polyester nonwoven substrate is used. By using the above-described specific nonwoven fabric substrate, peeling of the plating layer formed by the plating treatment can be prevented, and a conductive adhesive sheet having more excellent workability can be obtained. The wet polyester nonwoven fabric substrate can be obtained by paper-making a polyester fiber dispersed in water or the like. As the polyester fiber, a fiber having a diameter of, for example, 2 μm to 10 μm is preferably used, and a fiber having a diameter of 3 μm to 8 μm is more preferable. The papermaking method is not particularly limited, and examples thereof include a method using a cylinder paper machine, a short-wire paper machine, a long-wire paper machine, and a tilted short-web paper machine. The wet polyester nonwoven fabric substrate is preferably one which is heated in order to bond the polyester fibers after papermaking by the above method.

As the wet polyester nonwoven fabric substrate, it is preferable to use a basis weight of 2 g/m ² to 20 g/m ² in terms of both good flexibility and strength, and 4 g/m ² to 16 g. It is more preferable that the basis weight of the range of /m ^{2 is more than} the weight per unit area in the range of 6 g/m ² to 15 g/m ² , and it is more preferable to obtain a conductive adhesive sheet which is thin and excellent in workability.

As the wet polyester nonwoven fabric substrate, a thickness of 5 μ to 50 μm is preferably used, and a thickness of 10 μm to 30 μm is more preferable, and a thickness of 14 μm to 20 μm is particularly preferable.

As the wet polyester nonwoven fabric substrate, it is preferred to use a tensile strength in the MD (flow) direction of 2N/20 mm to 30 N/20 mm, preferably 5 N/20 mm to 28 N/20 mm, and 10 N/20 mm. 25N/20mm is even better. Further, as the wet polyester nonwoven fabric substrate, it is preferable to use a tensile strength of TD (width) of 0.3 N/20 mm to 30 N/20 mm, preferably 2N/20 mm to 27 N/20 mm, and 9N. /20mm~25N/20mm is even better. Further, the tensile strength is measured by stretching at a speed of 300 mm/min in accordance with JIS Z0237-2010.

The conductive substrate can be produced by applying a plating treatment including electroless plating treatment to the wet polyester nonwoven fabric substrate. Here, the "plating treatment including electroless plating treatment" refers to a treatment in which one or more electroless plating treatments are performed, and one or more electrolytic plating treatments are performed after the electroless plating treatment. The treatment and the treatment of one or more electroless plating treatments after one or more electrolytic plating treatments are performed. In the present invention, it is preferred to apply an electroless plating treatment or an electrolytic plating treatment after the electroless plating treatment, and it is more preferable to apply an electroless plating treatment after the electroless plating treatment. In the electroless plating treatment method, for example, the wet unsaturated polyester nonwoven substrate is immersed in a liquid containing a catalyst such as palladium or an electroless plating solution containing a metal ion and a reducing agent to form the nonwoven fabric. A method of forming a metal film on the surface of a substrate. Moreover, when performing the electroless plating treatment, in addition to the above steps, the step of washing the wet polyester nonwoven fabric substrate, the step of activating the catalyst, and the wet polyester nonwoven substrate and The step of washing or drying the plating treatment has been carried out. In a preferred method of the electroless plating treatment, after washing the wet polyester nonwoven fabric substrate and washing with water, the catalyst is applied to the wet polyester nonwoven substrate and washed with water, and the catalyst is activated and washed with water. A method in which a wet polyester-based nonwoven fabric substrate is immersed in an electroless plating solution, washed with water, and dried. When a metal ion contained in the electroless plating solution, for example, copper, nickel, silver, platinum, or aluminum, is used, at least one of copper or nickel is used, and it is preferable to use both of excellent conductivity and low cost. Copper ions are more preferable in terms of imparting more excellent adhesion.

The metal ion is preferably contained in an amount of 0.001 mol/l to 0.2 mol/l with respect to the electroless plating solution.

The metal ion is preferably from copper sulfate, nickel sulfate, nickel chloride, palladium chloride, silver chloride, silver nitrate, and the like. If copper sulfate, nickel sulfate, or nickel chloride is used, it is preferable. It is preferable in terms of conductivity and low cost in terms of ideal copper or nickel ions.

The reducing agent which may be contained in the electroless plating solution may, for example, be sodium hypophosphite, sodium borohydride, potassium borohydride, Rochelle salt, dimethylamine borane or diethylamine borane. Formalin, as a hydrazine hydrate, a hydrazine hydrochloride, a hydrazine hydrochloride, a hydrazine sulfate, a methyl hydrazine, a 1,2-dimethyl hydrazine, an acetamidine, a phenyl hydrazine, etc., hydrogen hydride, etc. It is preferred to use sodium hypophosphite or formalin. The reducing agent is preferably contained in an amount of from 0.001 mol/l to 0.4 mol/l with respect to the electroless plating solution. The electroless plating solution may contain, as an auxiliary component, a distoring agent, a pH adjuster, a buffer, a plating accelerator, a stabilizer, or the like in addition to the above components.

The above-mentioned troublesome agent, for example, organic acid salt such as sodium citrate, potassium citrate, Rochelle salt, thioglycolic acid, ammonia, triethanolamine, glycine, ethylenediamine, ethylenediamine 2 acetic acid For the salt, o-aminophenol, pyridine, etc., sodium citrate is preferably used. The above-mentioned distoring agent is preferably contained in an amount of from 0.001 mol/l to 4.0 mol/l with respect to the electroless plating solution.

As the pH adjusting agent, for example, sodium hydroxide, ammonium hydroxide, an inorganic acid, an organic acid or the like is preferably used.

As the buffering agent, for example, an organic acid, an alkali metal salt of an inorganic acid, sodium citrate, sodium acetate, ammonium chloride, ammonium sulfate, oxycarboxylic acid, dihydrogen phosphate, boric acid, carbonic acid or the like is preferably used.

As the plating accelerator, a sulfide, a fluoride or the like can be used.

As the stabilizer, a chloride, a sulfide, a nitrate, a 2,2-bipyridine, a 2-mercaptobenzoxazole, a nicotinic acid or the like can be suitably used.

In the electroless plating treatment, it is preferable that a metal such as copper is laminated on the surface of the wet polyester nonwoven fabric substrate, and it is possible to have more excellent adhesion and conductivity and to reduce the cost of the above treatment. In particular, it is preferably in the range of 1 g/m ² to 20 g/m ² , more preferably in the range of 3 g/m ² to 10 g/m ² , and even more preferably in the range of 5 g/m ² to 8 g/m ² .

As the conductive substrate used in the present invention, as described above, it is preferred to carry out the electroless plating treatment or the electrolytic plating treatment after the wet polyester-based nonwoven fabric substrate is subjected to an electroless metal plating treatment, and in particular, it has been used. When the electrolytic plating treatment is performed, the plating layer can be formed stably in a short period of time, so that it is possible to reduce the production cost and achieve high strength, which is more preferable.

As the electrolytic plating solution which can be used for the electrolytic plating treatment, for example, a copper plating solution including a copper pyrophosphate, a copper cyanide bath, a copper sulfate bath, or the like, including a Watts bath, a chlorination bath, and an amine group can be used. A nickel plating solution such as a sulfonic acid bath, a chrome plating solution including a chrome bath (Sargent bath), or a plating solution including gold, silver, tin, zinc, or the like.

When the outermost layer of the conductive substrate is a nickel-containing plating layer, the storage stability is excellent, and the wet polyester nonwoven substrate and the plating layer are excellent in adhesion and excellent in electrical conductivity, which is preferable. The outermost layer preferably contains nickel 1 g/m ² to 10 g/m ^{2 , more} preferably 2 g/m ² to 8 g/m ² , and contains 2.5 g/m ² to 6 g/m ² , which satisfies the aforementioned excellent preservation stability. It is more desirable in terms of adhesion and conductivity.

An ideal aspect of the conductive substrate is, for example, a conductive substrate obtained by sequentially performing electroless copper plating treatment and electrolytic nickel plating treatment on a wet polyester nonwoven substrate, and for wet polymerization. The ester-based nonwoven fabric substrate was sequentially subjected to electroless copper plating treatment, electrolytic copper plating treatment, and electrolytic nickel plating treatment.

Next, the conductive adhesive layer constituting the conductive adhesive sheet of the present invention will be described. In the conductive adhesive layer, the conductive particles are contained in an amount of 3 to 50% by mass based on the total amount of the conductive adhesive layer. The conductive adhesive sheet having the conductive adhesive layer has excellent conductivity. The conductive adhesive layer is preferably used in an amount of from 5 to 50% by mass based on the total amount of the conductive adhesive layer, and more preferably from 10% by mass to 50% by mass, and more preferably from 15% by mass to 45% by mass. When the mass is %, it is more preferable because it exhibits superior electrical conductivity and can withstand the degree of flexibility and reworkability of the height difference of the adherend.

The conductive adhesive layer is preferably a thickness of 3 μm to 25 μm, more preferably 5 μm to 20 μm, and a thickness of 7 μm to 18 μm, whereby a conductive adhesive sheet having better adhesion and thickness can be obtained.

The conductive adhesive layer can be formed by using an adhesive composition containing conductive particles and an adhesive component.

As the conductive particles contained in the conductive adhesive layer, for example, metal particles such as gold, silver, copper, nickel, or aluminum, conductive resin particles such as carbon or graphite, or the above-mentioned resin or medium-solid glass beads or hollow glass beads can be used. There are metal-coated particles on the surface. In particular, when the conductive particles are made of nickel particles, copper particles or silver particles, it is preferable in that it has more excellent conductivity and adhesion strength and can improve the productivity of the conductive adhesive sheet. Further, the conductive particles are, for example, nickel particles having a needle-like shape having a plurality of needle-like shapes on the surface of the particles, which are produced by a carbonyl method, or spherical particles which are smoothed by the surface acicular particles. Or copper particles or silver particles produced by ultra-high pressure cycloidback water micronization.

It is preferable that the conductive particles are spherical or surface-needle-shaped. The conductive particles preferably have an aspect ratio of 1 to 2, preferably 1 to 1.5 aspect ratio, and more preferably 1 to 1.2 aspect ratio. The aspect ratio can be measured by observing the surface of the conductive particles with a scanning electron microscope.

When the conductive particles have a tap density of 2 g/cm ³ to 7 g/cm ³ , it is less likely to settle or aggregate when the conductive adhesive layer is formed. Therefore, it is preferable to use 3 g/cm ³ to 6 g / The tap density of cm ³ is better, and the tap density of 4 g/cm ³ to 5 g/cm ³ is better.

The conductive particles are preferably those having a particle diameter d50 of from 3 μm to 20 μm and a particle diameter d85 of from 6 μm to 40 μm. The particle diameter d50 of the conductive particles is more preferably 4 μm to 15 μm, still more preferably 5 μm to 12 μm, still more preferably 6 μm to 10 μm. Further, the particle diameter d85 of the conductive particles is more preferably 8 μm to 30 μm, still more preferably 9 μm to 25 μm, still more preferably 10 μm to 20 μm. Further, when two or more kinds of conductive particles are used in combination, the average particle diameters d50 and d85 of these mixtures are preferably in the above range.

Further, the aforementioned particle diameter d50 represents 50% cumulative □ (median diameter) in the particle size distribution, and the aforementioned particle diameter d85 represents 85% accumulation □. Specifically, the aforementioned particle diameter means a □ measured by a laser analysis-scattering method. It is measured by a laser diffraction type particle size distribution analyzer SALD-3000 manufactured by Shimadzu Corporation.

Preferably, the conductive particles are preferably 50% to 150% of the thickness of the conductive adhesive layer, and preferably 60% to 120%, and 70% to 100%. good. Further, it is preferable that the conductive particles have a particle diameter d85 of 80% to 200% of the thickness of the conductive adhesive layer, preferably 100% to 150%, and 110% to 140%. Better yet. By the conductive particles having the particle diameters d50 and d85, the conductivity and the adhesion strength can be further improved, and the production efficiency of the conductive adhesive sheet can be further improved.

The conductive particles are preferably in a range of from 5 parts by mass to 100 parts by mass per 100 parts by mass of the adhesive component (solid content) contained in the conductive adhesive layer, and preferably in a range of from 10 parts by mass to 100 parts by mass. In the range of 20 parts by mass to 80 parts by mass, it is particularly preferable because the conductivity and the adhesive strength are more excellent, and the production efficiency of the conductive adhesive sheet is further improved. Specifically, the conductive particles are preferably in the range of 5 parts by mass to 100 parts by mass, and 10 parts by mass to 100 parts by mass, based on 100 parts by mass of the acrylic polymer (solid content) contained in the conductive adhesive layer. In the range of 20 parts by mass to 80 parts by mass, the conductivity and the adhesive strength are more excellent, and the production efficiency of the conductive adhesive sheet is further improved, which is particularly preferable.

A method of mixing the conductive particles with the pressure-sensitive adhesive component, for example, a method of mixing an electrically conductive substance and an adhesive component such as an acrylic polymer which is an adhesive component with the additive or the like. The adhesive component such as the above acrylic polymer may be preliminarily mixed with a solvent and an optional additive. For the above mixing, a dispersing mixer such as a dissolver, a butterfly mixer, a BDM2-axis mixer, or a planetary mixer can be used. Among them, a dissolving machine or a butterfly type mixer which can apply shear which suppresses the degree of increase in viscosity during the mixing is preferably used.

Further, an adhesive component constituting the conductive adhesive layer, for example, an acrylic pressure-sensitive adhesive composition, an anthrone-based pressure-sensitive adhesive composition, a rubber-based pressure-sensitive adhesive composition, or the like. Among them, in view of the reduction in the production cost of the conductive adhesive sheet and the improvement of the adhesiveness, it is preferred to use the acrylic adhesive composition as the adhesive component.

As the acrylic pressure-sensitive adhesive composition, for example, an acrylic polymer can be used. The acrylic polymer can be obtained by polymerizing a monomer component. As the monomer component, for example, a monomer component containing a (meth) acrylate having an alkyl group having 1 to 14 carbon atoms can be used. The above (meth) acrylate having an alkyl group having 1 to 14 carbon atoms may be used alone, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, Isobutyl methacrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, (meth) acrylate Ethyl ester, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, or the like, or a combination of two or more of them. Among them, the (meth) acrylate having an alkyl group having 1 to 14 carbon atoms is preferably a (meth) acrylate having an alkyl group having 4 to 12 carbon atoms, more preferably a carbon atom. The (meth) acrylate having a linear or branched alkyl group of 4 to 9 is more preferably used alone or in combination of n-butyl acrylate or 2-ethylhexyl acrylate.

The (meth) acrylate having an alkyl group having 1 to 14 carbon atoms is preferably used in an amount of from 80% by mass to 98.5% by mass based on the total amount of the monomer component, and is preferably from 90% by mass to 98.5% by mass. The range is better.

Further, when the acrylic polymer used in the present invention is produced, a polar vinyl monomer can be used as the monomer component. The polar vinyl monomer may be one or more selected from the group consisting of a vinyl monomer having a hydroxyl group, a vinyl monomer having a carboxyl group, and a vinyl monomer having a mercapto group.

a vinyl monomer having a carboxyl group, and acrylic acid, methacrylic acid, itaconic acid, maleic acid, (meth)acrylic acid dimer, crotonic acid, ethylene oxide-modified succinic acid acrylate, etc., wherein Acrylic acid or methacrylic acid is preferred, and acrylic acid is preferred.

The vinyl monomer having a carboxyl group is preferably used in an amount of preferably 1% by mass to 10% by mass based on the total amount of the monomer component, more preferably 1.5% by mass to 6% by mass, and 2% by mass to 4% by mass. In addition, it is preferable that the initial adhesive strength of the metal surface constituting the adherend is excellent, and the conductive adhesive tape exhibits excellent adhesion strength to the adherend even when stored under high temperature and high humidity. In addition, when the amount of the acrylic acid having a carboxyl group-containing vinyl monomer is in the range of 1% by mass to 6% by mass based on the total amount of the monomer component, it is possible to achieve better moisture permeability and adhesion to the adherend. Strength, it is ideal.

As the vinyl monomer having a hydroxyl group, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, (methyl) can be used. A hydroxyl group-containing (meth) acrylate such as 6-hydroxyhexyl acrylate.

As the above-mentioned vinyl monomer having a mercapto group, for example, N-vinylrrolidone, N-vinylcaprolactam, acrylonitrile, acrylamide, N,N-dimethylpropene can be used. Amidoxime and the like.

As the other vinyl monomer, a sulfonic acid group-containing monomer such as vinyl acetate, ethylene oxide-modified succinic acid acrylate, 2-propenylamine-2-methylpropane sulfonic acid, or the like can be used. A terminal alkoxy-modified (meth) acrylate such as 2-methoxyethyl acrylate or 2-phenoxyethyl (meth)acrylate.

The polar vinyl monomer is preferably used in an amount of preferably 0.2% by mass to 15% by mass based on the total amount of the monomer component, more preferably 0.4% by mass to 10% by mass, and preferably 0.5% by mass to 6% by mass. If the amount of the range is used, it is easy to adjust the adhesive strength to a desired range, which is preferable.

The acrylic polymer can be produced by polymerizing the monomer component by a known method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, or an emulsion polymerization method, and in consideration, production cost reduction and production efficiency are achieved. For improvement, it is preferred to use a solution polymerization method. The acrylic polymer obtained by the above method is preferably one having a weight average molecular weight of 300,000 to 1,500,000, and preferably having a weight average molecular weight of 500,000 to 1,200,000.

In the conductive adhesive layer, it is preferable to form a three-dimensional crosslinked structure in consideration of an effect of further improving the cohesive force and exhibiting more excellent adhesion. The degree of crosslinking can be grasped by using a gel fraction represented by an insoluble component after being immersed in a toluene of a good solvent of the acrylic polymer for 24 hours. The conductive adhesive layer preferably has a gel fraction of 25% by mass to 65% by mass, more preferably 35% by mass to 60% by mass, and 40% by mass to 55% by mass. The direction of cohesion and peeling resistance are better, so it is more preferable.

Further, the gel fraction can be calculated by the following formula. Gel fraction (% by mass) = {(adhesive layer quality after toluene impregnation) / (mass of adhesive layer before toluene impregnation)} × 100 Adhesive layer quality = (mass of conductive adhesive sheet) - (mass of substrate) - (mass of conductive particles)

When the conductive adhesive layer having a crosslinked structure is formed, it is preferred to use an adhesive such as the above-mentioned acrylic polymer or the like. For the crosslinking agent, for example, an isocyanate crosslinking agent, an epoxy crosslinking agent, a chelating agent crosslinking agent, an aziridine crosslinking agent, or the like can be used. The type of the above-mentioned crosslinking agent should preferably correspond to the functional group possessed by the aforementioned acrylic polymer. For example, in the case where the acrylic polymer is a carboxyl group, it is preferred to use an isocyanate crosslinking agent. The crosslinking agent is preferably one in which the gel fraction of the conductive adhesive layer is in the above range.

The conductive adhesive layer may contain an adhesion-imparting resin in order to further improve the adhesion. For the adhesion-imparting resin, for example, a petroleum resin such as a rosin-based resin, a olefin-based resin, an aliphatic (C5-based) or an aromatic (C9-based), a styrene-based resin phenol-based resin, a xylene-based resin, or a methacrylic acid can be used. Systematic resin, etc. Among them, the adhesive-imparting resin is preferably a rosin-based resin, and a polymerized rosin-based resin is more preferable. The amount of the adhesion-imparting resin to be used is preferably in the range of 10 parts by mass to 50 parts by mass based on 100 parts by mass of the (meth)acryl-based polymer. The conductive adhesive layer may contain various additives as needed. As the above additives, for example, a plasticizer, a softener, a metal passivator, an antioxidant, a pigment, a dye, or the like can be used. The conductive adhesive layer can be formed into an adhesive which can be used, and those having a predetermined amount of the conductive material and the adhesive component can be used.

Further, as the conductive adhesive layer, those containing a triazole compound can be used. As the above triazole compound, for example, benzotriazole, tolyltriazole and potassium salts thereof, 3-(N-cannonyl)amino-1,2,4triazole, 2-(2'-hydroxy-5methyl group can be used. When benzotriazole or the like is used, it is particularly preferable because it can have excellent adhesion retention and can suppress a decrease in adhesion strength which may occur when placed in a high-temperature and high-humidity environment.

The triazole-based compound is preferably used in an amount of from 0.05 part by mass to 3.0 parts by mass per 100 parts by mass (solid content) of the acrylic pressure-sensitive adhesive composition, and more preferably in a range of from 0.1 part by mass to 1.5 parts by mass. In the range of 0.3 parts by mass to 1.0 part by mass, it is particularly preferable because it has excellent adhesion holding power and can suppress a decrease in adhesive strength which may occur when placed in a high-temperature and high-humidity environment.

The adhesive obtained by the foregoing method can be used alone for the formation of the conductive adhesive layer. The solid content of the above-mentioned adhesive is preferably in the range of 10% by mass to 70% by mass, more preferably in the range of 30% by mass to 55% by mass, and even more preferably in the range of 43% by mass to 50% by mass.

The conductive adhesive sheet of the present invention can be produced by, for example, coating the surface of the release film with a roll coater or a die coater, and applying the adhesive layer to an environment of about 50 ° C to 120 ° C. Drying and removing the solvent to form a conductive adhesive layer, and then laminating the conductive adhesive layer on both surfaces of the conductive substrate, and if necessary, performing thermal lamination, etc., and secondly, performing at a temperature of about 15 ° C to 50 ° C A hardening step of about 48 hours to 168 hours.

The above thermal layer is preferably carried out at 40 ° C to 120 ° C, more preferably 50 ° C to 100 ° C, and more preferably 60 ° C to 90 ° C.

Further, the conductive adhesive sheet of the present invention may have a film laminate before it is attached to the adherend. The release film, for example, paper such as kraft paper, cellophane, or paper; resin film such as polyethylene, polypropylene (OPP, CPP), or polyethylene terephthalate; lamination of the paper and the resin film The paper is a peeling treatment agent such as an ketone-based resin applied to one or both sides of the paper, which is treated with clay or polyvinyl alcohol.

A preferred configuration example of the conductive adhesive sheet of the present invention is shown in Figs. 1 and 2 . Fig. 1 shows a one-sided adhesive sheet in which a conductive adhesive layer 2 is laminated on a conductive substrate 1. In addition, FIG. 2 shows a double-sided adhesive sheet in which the conductive adhesive layer 2 is laminated on both surfaces of the conductive substrate 1. In such a structure, it is preferable to adopt a structure in which the surface of the adhesive layer 2 is provided with a release film.

The conductive adhesive sheet of the present invention is excellent in flexibility, good adhesion to an adherend, electrical conductivity, and reworkability, and is useful for electromagnetic wave shielding for use in electrical and electronic equipment, and for grounding with static electricity. In particular, it is suitable for use in the attachment of built-in parts of small electronic terminals such as portable electronic devices having convex and concave portions and difficult to attach conductive adhesive sheets. [Examples]

The following is a detailed description of the embodiments.

Production Example 1 [Electrically Conductive Substrate (A)] Wet polyester non-woven fabric "A type" manufactured by Miki Special Paper Co., Ltd. (10 g/m ² basis weight, 15 μm thickness, and 5 μm diameter of polyester fiber) The average diameter)) was washed with water in an aqueous solution containing 10 g/l of tin (II) chloride and 20 ml/l of hydrochloric acid at room temperature for about 5 minutes. Then, the water-washed non-woven fabric was immersed in an aqueous solution containing 1 g/l of palladium chloride and 20 ml/l of hydrochloric acid at room temperature for about 10 minutes, and then washed with water. Then, the water-washed non-woven fabric is contained in 10 g/l of copper sulfate, 7 ml/l of formaldehyde, 8 g/l of sodium hydroxide, 40 g/l of ethylenediaminetetraacetate (EDTA-4Na), and 0.25 ml/l of stabilizer. The electroless plating solution adjusted to 40 ° C was immersed for 20 minutes, and then washed with water to obtain a wet polyester nonwoven fabric which was subjected to electroless plating treatment. Then, the wet polyester non-woven fabric subjected to the electroless plating treatment is immersed in an electrolytic copper plating solution (manufactured by Kanno Pharmaceutical Co., Ltd., TOP LUCINA SF), and electrolytic copper plating treatment is performed to electrolyze the electrolytic copper plating. The copper plating amount of the liquid was 6 g/m ² , and a wet polyester non-woven fabric treated by electrolytic copper plating was obtained. Then, the aforementioned wet polyester non-woven fabric treated by electrolytic copper plating is immersed in 240 g/l of nickel sulfate, 45 g/l of nickel chloride, 30 g/l of boric acid, 2 g/l of saccharin and 1,4-butynediol 0.2. An electrolytic nickel plating solution of g/l is subjected to electrolytic nickel plating treatment in which the nickel plating amount of the electrolytic nickel plating solution is 4 g/m ² , washed with water, and dried to prepare a conductive substrate (A). .

Production Example 2 [Conductive Substrate (B)] The wet polyester non-woven fabric "A" manufactured by Miki Special Paper Co., Ltd. was replaced with the wet polyester non-woven fabric "SILKYFINE WS7A- manufactured by Asahi Kasei Co., Ltd." A conductive substrate (B) was produced in the same manner as in Production Example 1 except that the weight per unit area was 6 g/m ² , the thickness was 18 μm, and the diameter of the polyester fiber was 4.5 μm (average diameter).

Production Example 3 [Conductive Substrate (C)] The wet polyester non-woven fabric "A" manufactured by Miki Special Paper Co., Ltd. was replaced with the wet polyester non-woven fabric "SILKYFINE WS7A-" manufactured by Asahi Kasei Co., Ltd. A conductive substrate (C) was produced in the same manner as in Production Example 1 except that the weight per unit area was 4 g/m ² , the thickness was 16 μm, and the diameter of the polyester fiber was 4.5 μm (average diameter).

Production Example 4 [Conductive Substrate (D)] The wet polyester non-woven fabric "A" manufactured by Miki Special Paper Co., Ltd. was replaced with the wet polyester non-woven fabric "5.5" manufactured by Nippon Paper PAPYLIA Co., Ltd. A conductive substrate (D) was produced in the same manner as in Production Example 1 except that g/m ^{2 was used} (the weight per unit area was 5.5 g/m ² , the thickness was 14 μm, and the diameter of the polyester fiber was 4.5 μm (average diameter)). ).

Production Example 5 [Conductive Substrate (E)] A wet polyester non-woven fabric "A type" manufactured by Miki Special Paper Co., Ltd. at a normal temperature (weight per unit area: 10 g/m ² , thickness: 15 μm, polyester fiber) The diameter of 5 μm (average diameter) is immersed in an aqueous solution containing 10 g/l of tin (II) chloride and 20 ml/l of hydrochloric acid for about 5 minutes and washed with water, and then immersed in an aqueous solution containing 1 g/l of palladium chloride and 20 ml/l of hydrochloric acid. Take about 10 minutes and wash. Then, the water-washed non-woven fabric is immersed in 10 g/l containing copper sulfate, 7 ml/l of formaldehyde, 8 g/l of sodium hydroxide, 40 g/l of ethylenediaminetetraacetate (EDTA-4Na), and stabilizer (0.25 ml). /l) has been adjusted to 40 ° C in an electroless plating solution for 60 minutes, and the electroless plating solution is subjected to an electroless plating treatment in which the amount of copper plating is 6 g/m ² , and then washed with water and dried. A conductive substrate (E) was produced.

Production Example 6 [Conductive Substrate (F)] A wet polyester non-woven fabric "A type" manufactured by Miki Special Paper Co., Ltd. at room temperature (weight: 10 g/m ² , thickness 15 μm, polyester fiber) The diameter of 5 μm (average diameter) is immersed in an aqueous solution containing 10 g/l of tin (II) chloride and 20 ml/l of hydrochloric acid for about 5 minutes and washed with water, and then immersed in an aqueous solution containing 1 g/l of palladium chloride and 20 ml/l of hydrochloric acid. It takes about 10 minutes and is washed in water. Then, the non-woven fabric washed with the above water is immersed in 40 ° C containing nickel sulfate 20 g / l, sodium citrate 30 g / l, sodium hypophosphite 15 g / l and ammonium chloride 30 g / l and adjusted to pH 9.5 with aqueous ammonia. In the electroless plating solution, the electroless plating treatment in which the amount of nickel plating was 6 g/m ^{2 was} carried out for 60 minutes, and then washed with water and dried to prepare a conductive substrate (F).

Production Example 7 [Conductive Substrate (G)] A wet polyester non-woven fabric "A type" manufactured by Miki Special Paper Co., Ltd. at a normal temperature (weight per unit area: 10 g/m ² , thickness: 15 μm, polyester fiber) The diameter of 5 μm (average diameter) was immersed in an aqueous solution containing 10 g/l of tin (II) chloride and 20 ml/l of hydrochloric acid for about 5 minutes, and washed with water and immersed in an aqueous solution containing 1 g/l of palladium chloride and 20 ml/l of hydrochloric acid. About 10 minutes in the middle and washed. Then, the water-washed non-woven fabric is immersed in 10 g/l containing copper sulfate, 7 ml/l of formaldehyde, 8 g/l of sodium hydroxide, 40 g/l of ethylenediaminetetraacetate (EDTA-4Na), and stabilizer (0.25 ml). /l) was adjusted to 40 ° C in an electroless copper plating solution for 60 minutes, and the electroless copper plating solution obtained by the electroless copper plating solution was subjected to an electroless copper plating treatment of 6 g/m ² , followed by water washing to obtain a Wet polyester non-woven fabric treated with electroless copper plating. Then, the wet polyester non-woven fabric treated by the electroless copper plating is immersed in 20 g/l containing nickel sulfate, 30 g/l of sodium citrate, 15 g/l of sodium hypophosphite, and 30 g/l of ammonium chloride and more than ammonia. The electroless nickel plating solution having a pH of 9.5 and 40° C. was adjusted to an electroless nickel plating solution having a nickel plating amount of 4 g/m ² for 30 minutes, and then washed with water. A conductive substrate (G).

Production Example 8 [Electrically Conductive Substrate (H)] A wet polyester non-woven fabric "A type" manufactured by Miki Special Paper Co., Ltd. (weight: 10 g/m ² , thickness 15 μm, diameter of polyester fiber 5 μm ( The average diameter)) was washed with water at room temperature for about 5 minutes in an aqueous solution containing 10 g/l of tin (II) chloride and 20 ml/l of hydrochloric acid. Then, the non-woven fabric washed with the above water was immersed in an aqueous solution containing 1 g/l of palladium chloride and 20 ml/l of hydrochloric acid at room temperature for about 10 minutes, and then washed with water. Then, the water-washed non-woven fabric is immersed in 10 g/l containing copper sulfate, 7 ml/l of formaldehyde, 8 g/l of sodium hydroxide, 40 g/l of ethylenediaminetetraacetate (EDTA-4Na), and 0.25 ml/l of stabilizer. It was adjusted to an electroless plating solution at 40 ° C for 20 minutes, and then washed with water to obtain a wet polyester non-woven fabric which was subjected to electroless plating treatment. Then, the wet polyester non-woven fabric treated by the above electroless plating is immersed in 240 g/l of nickel sulfate, 45 g/l of nickel chloride, 30 g/l of boric acid, 2 g/l of saccharin and 1,4-butynediol 0.2. In the electrolytic nickel plating solution of the g/l, the nickel plating plating amount of the electrolytic nickel plating solution is 4 g/m ² of electrolytic nickel plating treatment, washed with water, and dried to prepare a conductive substrate (H). ).

Production Example 9 [Electrically conductive substrate (I)] PRECISE (manufactured by copper and nickel plating for a dry polyester nonwoven fabric) was used as the conductive substrate (I).

Production Example 10 [Electrically Conductive Substrate (J)] The wet polyester non-woven fabric "A type" manufactured by Miki Special Paper Co., Ltd. was replaced with a dry polyester non-woven fabric manufactured by JX Nippon Mining & Energy Co., Ltd. A conductive substrate (J) was produced in the same manner as in Production Example 1 except that "MELIFE TY0503FE" (weight: 8 g/m ² , thickness: 28 μm, and polyester fiber diameter: 12 μm (average diameter)).

Production Example 11 [Electrically conductive substrate (K)] [Plating non-woven fabric K] The wet polyester non-woven fabric "A type" manufactured by Miki Special Paper Co., Ltd. was replaced with JX Nippon Mining & Energy Co., Ltd. A conductive substrate was produced in the same manner as in Production Example 1 except that the dry polyester nonwoven fabric "MELIFE T10" (weight per unit area: 10 g/m ² , thickness: 28 μm, and polyester fiber diameter: 10 μm (average diameter)) was used. (K).

Production Example 12 [Conductive Substrate (L)] The wet polyester non-woven fabric "A" manufactured by Miki Special Paper Co., Ltd. was replaced with the wet linen non-woven fabric "D54E" manufactured by Nippon Paper PAPYLIA Co., Ltd. A conductive substrate (L) was produced in the same manner as in Production Example 1 except that the weight per unit area was 16 g/m ² and the thickness was 43 μm.

Preparation Example 1 [Preparation of Acrylic Adhesive Composition (1)] In a reaction vessel equipped with a cooling tube, a stirrer, a thermometer, and a dropping funnel, 96.4 parts by mass of n-butyl acrylate and 0.1 mass of 2-hydroxyethyl acrylate were used. 3.5 parts by weight of acrylic acid, and 0.1 parts by mass of 2,2'-azobisisobutyl butyl as a polymerization initiator were dissolved in 100 parts by mass of ethyl acetate, and the inside of the reaction vessel was replaced with nitrogen, and then at 80 ° C. This was polymerized for 12 hours to obtain an acrylic copolymer solution having a weight average molecular weight of 600,000. 10 parts by mass of the polymerized rosin pentaerythritol ester (manufactured by Arakawa Chemical Industry Co., Ltd., PENSEL D-135, softening point 135 ° C), and uneven rosin glyceride were blended with respect to 100 parts by mass of the solid content of the acrylic copolymer solution. (Arakawa Chemical Industry Co., Ltd., SUPERESTER A-100, softening point 100 ° C) 10 parts by mass, using ethyl acetate, adjusting the solid content concentration of the acrylic copolymer to 45% by mass to obtain an acrylic adhesive composition (1).

Preparation Example 2 [Preparation of Acrylic Adhesive Composition (2)] In a reaction vessel equipped with a cooling tube, a stirrer, a thermometer, and a dropping funnel, 99.9 parts by mass of n-butyl acrylate and 0.1 mass of 2-hydroxyethyl acrylate were used. 0.1 parts by mass of 2,2'-azobisisobutyl hydride as a polymerization initiator was dissolved in 100 parts by mass of ethyl acetate, and the inside of the reaction vessel was substituted with nitrogen, and then polymerized at 80 ° C for 12 hours to obtain An acrylic copolymer solution having a weight average molecular weight of 600,000. 10 parts by mass of a polymerized rosin pentaerythritol ester (manufactured by Arakawa Chemical Industries Co., Ltd., PENSEL D-135, softening point 135 ° C), and an uneven rosin glyceride (100 parts by mass) of the solid component of the acrylic copolymer solution 10 parts by mass of the Arakawa Chemical Industry Co., Ltd., SUPERESTER A-100, softening point 100 ° C), and the solid content concentration of the acrylic copolymer was adjusted to 45% by mass using ethyl acetate to obtain an acrylic adhesive composition ( 2).

Preparation Example 3 [Preparation of Acrylic Adhesive Composition (3)] In a reaction vessel equipped with a cooling tube, a stirrer, a thermometer, and a dropping funnel, 92.9 parts by mass of n-butyl acrylate and 0.1 mass of 2-hydroxyethyl acrylate were used. 7 parts by mass of acrylic acid, and 2 parts by mass of 2,2'-azobisisobutyl butyl as a polymerization initiator were dissolved in 100 parts by mass of ethyl acetate, and the inside of the reaction vessel was substituted with nitrogen, and then the mixture was replaced at 80 ° C at 80 ° C. After polymerization for 12 hours, an acrylic copolymer solution having a weight average molecular weight of 600,000 was obtained. 10 parts by mass of the polymerized rosin pentaerythritol ester (manufactured by Arakawa Chemical Industry Co., Ltd., PENSEL D-135, softening point 135 ° C), and uneven rosin glyceride were blended with respect to 100 parts by mass of the solid content of the acrylic copolymer solution. 10 parts by mass of (available from Arakawa Chemical Co., Ltd., SUPERESTER A-100, softening point: 100 ° C), and the solid content concentration of the acrylic copolymer was adjusted to 45% by mass using ethyl acetate to obtain an acrylic adhesive composition. (3).

Preparation Example 4 [Preparation of Acrylic Adhesive Composition (4)] In a reaction vessel equipped with a cooling tube, a stirrer, a thermometer, and a dropping funnel, 97.4 parts by mass of n-butyl acrylate and 0.1 mass of 2-hydroxyethyl acrylate were used. 2.5 parts by weight of acrylic acid, 0.1 parts by mass of 2,2'-azobisisobutyl butyl as a polymerization initiator, and dissolved in 100 parts by mass of ethyl acetate, and the inside of the reaction vessel was substituted with nitrogen, and then it was made at 80 ° C. After polymerization for 12 hours, an acrylic copolymer solution having a weight average molecular weight of 600,000 was obtained. 10 parts by mass of a polymerized rosin pentaerythritol ester (manufactured by Arakawa Chemical Industries Co., Ltd., PENSEL D-135, softening point 135 ° C), and an uneven rosin glyceride (100 parts by mass) of the solid component of the acrylic copolymer solution 10 parts by mass of the Arakawa Chemical Industry Co., Ltd., SUPERESTER A-100, softening point 100 ° C), and the solid content concentration of the acrylic copolymer was adjusted to 45% by mass using ethyl acetate to obtain an acrylic adhesive composition ( 4).

Preparation Example 5 [Preparation of Conductive Adhesive Composition (1A-1)] 100 parts by mass of the acrylic adhesive composition (1) (solid content: 45 mass%), manufactured by Fukuda Metal Foil Powder Co., Ltd. Nickel powder "NI123J" (particle diameter d50: 6.3 μm, particle diameter d85: 10.0 μm, tap density: 4.3 g/cm ³ , and Inco Limited "NI123" smoothed) 22.5 parts by mass, and 2.5 parts by mass of BURNOCK NC40 (isocyanate crosslinking agent manufactured by DIC Co., Ltd., solid content: 40% by mass), and 0.23 parts by mass of benzotriazole, and adjusted solid content concentration using ethyl acetate After being 47% by mass, the mixture was stirred for 10 minutes using a dispersing mixer to obtain a conductive adhesive (1A-1).

Preparation Example 6 [Preparation of Conductive Adhesive Composition (1A-2)] The amount of nickel powder "NI123J" manufactured by Fukuda Metal Foil Industry Co., Ltd. was changed from 22.5 parts by mass to 9 parts by mass. A conductive adhesive (1A-2) was obtained in the same manner as in Production Example 5 except for the above.

Preparation Example 7 [Preparation of Conductive Adhesive Composition (1A-3)] The amount of nickel powder "NI123J" manufactured by Fukuda Metal Foil Powder Co., Ltd. was changed from 22.5 parts by mass to 36 parts by mass. A conductive adhesive (1A-3) was obtained in the same manner as in Production Example 5 except for the above.

Preparation Example 8 [Preparation of Conductive Adhesive Composition (1A-4)] The amount of nickel powder "NI123J" manufactured by Fukuda Metal Foil Industry Co., Ltd. was changed from 22.5 parts by mass to 0 parts by mass. A conductive adhesive (1A-4) was obtained in the same manner as in Production Example 5 except for the above.

Preparation Example 9 [Preparation of Conductive Adhesive Composition (1A-5)] The amount of nickel powder "NI123J" manufactured by Fukuda Metal Foil Powder Co., Ltd. was changed from 22.5 parts by mass to 67.5 parts by mass. A conductive adhesive (1A-5) was obtained in the same manner as in Production Example 5 except for the above.

Preparation Example 10 [Preparation of Conductive Adhesive Composition (2A)] The acrylic pressure-sensitive adhesive composition (1) was replaced with the acrylic pressure-sensitive adhesive composition (2), and the preparation example 5 was used. The same method was used to obtain a conductive adhesive (2A).

Preparation Example 11 [Preparation of Conductive Adhesive Composition (3A)] The acrylic pressure-sensitive adhesive composition (1) was replaced with the acrylic pressure-sensitive adhesive composition (3), and the preparation example 5 was used. The same method was used to obtain a conductive adhesive (3A).

Preparation Example 12 [Preparation of Conductive Adhesive Composition (4A)] The acrylic pressure-sensitive adhesive composition (1) was replaced with the acrylic pressure-sensitive adhesive composition (4), and the preparation example 5 was used. The same method was used to obtain a conductive adhesive (4A).

Preparation Example 13 [Preparation of Conductive Adhesive Composition (1B)] Nickel powder "NI123J" manufactured by Fukuda Metal Foil Co., Ltd. was replaced with nickel powder "NI123" manufactured by INCO LIMITED (particle diameter d50) A conductive adhesive (1B) was obtained in the same manner as in Production Example 5 except that the amount of the material was changed to 22.5 parts by mass.

(Example 1) The conductive adhesive composition (1A-1) was applied to a release film "PET38 × 1 A3" manufactured by NIPPA Co., Ltd. using a comma coater. The thickness of the conductive adhesive layer after drying was 9 μm, and it was dried in a desiccator set at 80 ° C for 2 minutes to prepare a conductive adhesive layer. Then, the conductive adhesive layer was attached to both surfaces of the conductive substrate (A), and this was thermally laminated at 80 ° C, followed by curing at 40 ° C for 48 hours to prepare a conductive adhesive sheet.

(Example 2) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive substrate (A) was replaced with the conductive substrate (B).

(Example 3) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive substrate (A) was replaced with a conductive substrate (C).

(Example 4) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive substrate (A) was replaced with a conductive substrate (D).

(Example 5) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive adhesive composition (1A-1) was replaced with the conductive adhesive composition (1A-2).

(Example 6) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive adhesive composition (1A-1) was replaced with the conductive adhesive composition (1A-3).

(Example 7) The conductive adhesive composition (1A-1) was replaced with the conductive adhesive composition (2A), and the hardening time was changed from 48 hours to 120 hours, except for Example 1 A conductive adhesive sheet was produced in the same manner.

(Example 8) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive adhesive composition (1A-1) was replaced with the conductive adhesive composition (3A).

(Example 9) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive adhesive composition (1A-1) was replaced with the conductive adhesive composition (4A).

(Example 10) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the thickness of the conductive adhesive layer was changed from 9 μm to 7 μm.

(Example 11) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the thickness of the conductive adhesive layer was changed from 9 μm to 15 μm.

(Example 12) The conductive adhesive composition (1A-1) was replaced with a conductive adhesive composition (1B), and the thickness of the conductive adhesive layer was changed from 9 μm to 18 μm, in addition to In Example 1, a conductive adhesive sheet was produced in the same manner.

(Example 13) The conductive adhesive composition (1A-1) was replaced with a conductive adhesive composition (1B), and the thickness of the conductive adhesive layer was changed from 9 μm to 13 μm, in addition to In Example 1, a conductive adhesive sheet was produced in the same manner.

(Example 14) A conductive adhesive sheet of Example 14 was produced in the same manner as in Example 1 except that the plated nonwoven fabric A was replaced with the plated nonwoven fabric E.

(Example 15) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive substrate (A) was replaced with a conductive substrate (F).

(Example 16) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive substrate (A) was replaced with a conductive substrate (G).

(Example 17) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive substrate (A) was replaced with a conductive substrate (H).

(Comparative Example 1) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive substrate (A) was replaced with the conductive substrate (I).

(Comparative Example 2) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive substrate (A) was replaced with a conductive substrate (J).

(Comparative Example 3) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive substrate (A) was replaced with a conductive substrate (K).

(Comparative Example 4) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive substrate (A) was replaced with a conductive substrate (L).

(Comparative Example 5) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive adhesive composition (1A-1) was replaced with the conductive adhesive composition (1A-4).

(Comparative Example 6) A conductive adhesive sheet was produced in the same manner as in Example 1 except that the conductive adhesive composition (1A-1) was replaced with the conductive adhesive composition (1A-5).

(Reference Example 1) The conductive base material (A) was replaced with an electrolytic copper foil (CF-T9FZ-SV, manufactured by Fukuda Metal Foil Powder Co., Ltd.) treated with an inorganic rust preventive (chromium salt) having a thickness of 9 μm. A conductive adhesive sheet was produced in the same manner as in Example 1 except for the above.

The following evaluations were performed on the conductive substrate, the conductive adhesive layer, and the conductive adhesive sheet, and the results obtained are shown in the following table. Moreover, the amount of acrylic acid in the table represents the amount (% by mass) of the amount of all the monomer components used for the production of acrylic acid with respect to the production of the acrylic copolymer. Moreover, the amount of the metal powder in the table represents the content (% by mass) of the conductive particles with respect to the entire conductive adhesive layer. The results of the follow-up evaluation of Example 1 and Reference Example 1 are shown in FIGS. 3 and 4.

[Particle size] The particle diameter of the conductive particles is measured by using a laser diffraction type particle size distribution analyzer SALD-3000 manufactured by Shimadzu Corporation, using isopropyl alcohol as a dispersion medium.

[Electrical Conductive (Electrically Conductive Adhesive Sheet)] One side of a 30 mm wide by 30 mm wide conductive adhesive sheet was attached to a 25 mm × 25 mm brass electrode. A copper foil (thickness 35 μm) of 30 mm × 80 mm was attached to the other side of the conductive adhesive sheet. In a state where a load of a surface pressure of 20 N is applied from the brass electrode, a milliohm meter (NF circuit design system) is used in the environment of 23 ° C and 50% RH between the brass electrode and the copper foil connection terminal. The resistance □ when the current of 10 μA was passed was measured. When the aforementioned resistance □ is 500 mΩ or less, it is rated as acceptable.

[Thickness (Conductive Adhesive Layer)] A conductive adhesive layer formed on the release film using each of the conductive adhesive compositions was prepared by using a substrate PET film of 25 μm (S25 manufactured by UNITIKA Co., Ltd.), and TESTER was used. The thickness of the thickness meter "TH-102" manufactured by the company was measured. The thickness obtained by subtracting the thickness of the release film and the PET film from the above measurement □ is defined as the thickness of the conductive adhesive layer.

[Thickness (Conductive Adhesive Sheet)] The thickness of the conductive adhesive sheet was measured using a thickness gauge "TH-102" manufactured by TESTER Industries.

[Electrical Conductive (Conductive Substrate)] A conductive substrate having a width of 30 mm × 30 mm was sandwiched between two 25 mm × 25 mm brass electrodes, and a load of 20 N was applied from the brass electrode. A brass electrode was connected to the terminal, and the resistance □ at a current of 10 μA was measured using a milliohm meter (NF circuit design system) in an environment of 23 ° C and 50% RH.

[Adhesive Force] A 20 mm-thick conductive adhesive sheet was prepared, and a polyethylene terephthalate film (S25 manufactured by UNITIKA Co., Ltd.) having a thickness of 25 μm was used as a test piece. Then, a stainless steel plate (hereinafter referred to as a stainless steel plate) subjected to a hairline grinding treatment using a water-resistant abrasive paper No. 360 was attached to the top surface of the test piece at 23 ° C and 50% RH. The 2.0 kg roller was pushed back and forth once and crimped. Then, the pressure-bonded product was allowed to stand at room temperature for 1 hour, and then subjected to a test at a tensile speed of 300 mm/min at a normal temperature using a tensile tester (TENSILON RTA-100, manufactured by A&D Co., Ltd.) to measure a 180-degree peeling adhesive force. The above adhesion test was carried out for each of the adhesive layers (adhesive layers on both sides) of the conductive adhesive sheet, and the lower one was recorded in the table.

[Follow-up] The conductive adhesive sheet was attached to a slightly semicircular metal plate having a height of 5 mm and a width of 10 mm, and the followability to the height difference was evaluated. ○: Failure to follow the height difference. ×: Failed to follow the height difference and appear to float or rupture.

[Reworkability 1] It was evaluated whether or not the stainless steel plate had residual glue when the adhesion was measured by the aforementioned method. ◎: no residual glue. ○: Residue was present in a range of less than 10% with respect to the area of the stainless steel plate. ×: Residue was present in a range of 10% or more with respect to the area of the stainless steel plate.

[Reworkability 2] Whether or not the conductive adhesive sheet was broken when the adhesive force was measured by the above method was evaluated. The test was carried out using 5 sheets of conductive adhesive sheets and evaluated on the following basis. ◎: None of the 5 pieces were broken. ○: There are 4 pieces without cracks. ×: There were two or more cracks.

【Table 1】

【Table 2】

【table 3】

As is apparent from the above table, the adhesive sheets of Examples 1 to 18 of the present invention are excellent in followability, and also have good adhesion, electrical conductivity, and reworkability. On the other hand, in the adhesive sheets of Comparative Examples 1 to 4, although the followability, conductivity, and adhesion were excellent, the workability was remarkably poor. The adhesive sheet of Comparative Example 5 had poor conductivity. The adhesive sheet of Comparative Example 6 had poor adhesion and reworkability. Moreover, the followability of the adhesive sheet of the reference example was not good, and floating and cracking occurred in the step portion. [symbol □ Ming]

1 Conductive substrate 2 Conductive adhesive layer

1. . . Conductive substrate

2. . . Conductive adhesive layer

1. . . Conductive substrate

2. . . Conductive adhesive layer

Claims (14)

A conductive adhesive sheet having a conductive adhesive layer on at least one side of a conductive substrate; the conductive substrate is applied to a wet polyester nonwoven substrate including electroless plating In the plating treatment, the conductive adhesive layer contains 3 to 50% by mass of the conductive particles with respect to the entire conductive adhesive layer. The conductive adhesive sheet of claim 1, wherein the conductive particles contain copper or nickel. The electroconductive plating sheet according to claim 1, wherein the electroless plating treatment is performed using at least one of copper or nickel. The conductive adhesive sheet according to the first aspect of the invention, wherein the conductive substrate is subjected to electroless plating treatment to the wet polyester nonwoven substrate, and further subjected to electroless plating treatment or electrolytic plating. Apply the treatment. The conductive adhesive sheet according to claim 4, wherein the conductive substrate is subjected to electroless nickel plating treatment on the wet polyester nonwoven substrate, and further subjected to electrolytic nickel plating treatment. By. The conductive adhesive sheet according to claim 4, wherein the conductive substrate is subjected to electroless copper plating treatment, electrolytic copper plating treatment, and electrolytic nickel plating to the wet polyester nonwoven substrate in this order. Apply the treatment. The conductive adhesive sheet according to claim 1, wherein the conductive adhesive layer is a layer formed of an acrylic adhesive containing conductive particles and an acrylic polymer, and the acrylic polymer contains 1 The monomer component of acrylic acid having a mass % to 6% by mass is polymerized. The conductive adhesive sheet according to claim 1, wherein the wet polyester nonwoven substrate has a basis weight of 2 g/m ² to 20 g/m ² . The conductive adhesive sheet according to claim 1, wherein the wet polyester nonwoven substrate has a thickness of 5 μm to 50 μm. The conductive adhesive sheet of claim 1, wherein the wet polyester nonwoven substrate has a tensile strength (MD direction) of 2N/20 mm to 30 N/20 mm, and tensile strength (TD direction) thereof. It is 0.3N/20mm~30N/20mm. The conductive adhesive sheet according to claim 1, wherein the conductive adhesive layer has a thickness of from 3 μm to 25 μm, and the conductive particles have an average particle diameter d50 of from 3 μm to 20 μm. The conductive adhesive sheet according to claim 1, wherein the conductive adhesive layer and the conductive substrate are laminated at a temperature of from 40 ° C to 120 ° C to be laminated. A method for producing a conductive adhesive sheet, characterized in that the conductive adhesive layer is placed on at least one side of the conductive substrate, and then laminated at a temperature of from 40 ° C to 120 ° C. An electronic terminal having a structure in which a conductive adhesive sheet according to any one of claims 1 to 12 is attached to a part.