JP2005314480A - Electrically conductive adhesive tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrically conductive adhesive tape of high electrical conductivity while maintaining its tackiness. <P>SOLUTION: The electrically conductive adhesive tape is such that a tape- or sheet-like substrate is provided with electrically conductive adhesive layers. Specifically, the electrically conductive adhesive tape is characterized by that (1) the substrate is electrically nonconductive, both sides of which are provided, respectively, with the electrically conductive adhesive layers each with a foamed or nonfoamed adhesive resin or elastomer as the main component containing nanoscale fine carbon fibers and (2) when the resin is a thermoplastic resin, its melt index(MI) is 2-40 g/10min. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a conductive pressure-sensitive adhesive tape or sheet (generically referred to as “tape” in the present specification), and more particularly to a conductive pressure-sensitive adhesive tape having excellent conductivity while maintaining the pressure-sensitive adhesiveness.

  Conventionally, a conductive adhesive tape made by laminating a conductive adhesive layer in which a conductive substance such as metal powder is dispersed in an adhesive and a flexible conductive substrate such as metal foil has been used. Has been.

  As the conductive adhesive for the conventional conductive pressure-sensitive adhesive layer, a material in which a conductive material such as copper powder, silver powder, nickel powder, aluminum powder or the like is dispersed in the pressure-sensitive adhesive is generally used. However, in such a conductive pressure-sensitive adhesive, in order to obtain excellent conductivity, the conductive material particles are brought into close contact with each other and the contact between the particles and the conductive base material and the adherend. When a large amount of the conductive material is contained, the adhesive strength is reduced. On the other hand, if the content of the conductive material is reduced to increase the adhesive strength, the above-described contact becomes insufficient, resulting in a problem that the electrical conductivity is lowered. there were.

To solve this problem,
Patent Document 1 discloses a conductive pressure-sensitive adhesive in which one or both of carbon nanotubes and carbon microcoils are dispersed in a pressure-sensitive adhesive, and in addition, either or both of ferrite and metal silicon are dispersed. A conductive pressure-sensitive adhesive tape formed by laminating a conductive pressure-sensitive adhesive layer formed in a tape shape or a sheet shape and a flexible conductive base material is disclosed.

  Patent Document 2 discloses a conductive material in which a semiconductive pressure-sensitive adhesive in which a polymer antistatic agent or carbon nanotube is mixed into a pressure-sensitive adhesive is applied to the surface of a substrate such as cellophane or a resin band to form a semiconductive pressure-sensitive adhesive layer. An adhesive tape is disclosed.

With the techniques described in Patent Documents 1 and 2, it has been difficult to effectively solve the conductivity while maintaining tackiness (adhesiveness).
JP 2001-172582 A JP2002-2773

  This invention was made in order to solve such a problem, and makes it a subject to provide the electroconductive adhesive tape excellent in electroconductivity, maintaining adhesiveness.

The present invention for solving the above problems has the following configuration.
1. In a conductive pressure-sensitive adhesive tape in which a conductive pressure-sensitive adhesive layer is provided on a tape or sheet-like base material, the base material is non-conductive, and a foamed or non-foamed adhesive resin or elastomer is a main component on both surfaces of the base material. A conductive pressure-sensitive adhesive tape comprising a conductive pressure-sensitive adhesive layer containing nanoscale fine carbon fibers.

2. When the resin is a thermoplastic resin, the melt index (MI) is 2 g / 10 min. -40 g / 10 min. 2. The conductive pressure-sensitive adhesive tape as described in 1 above, wherein

3. 2. The conductive adhesive tape according to 1 above, wherein the elastomer has a Williams plasticity of 80 to 400.

4). 4. The conductive adhesive tape according to any one of 1 to 3, wherein the fine carbon fiber is at least one kind or a mixture of two or more kinds of carbon nanotubes and carbon nanowires.

5). 5. The conductive pressure-sensitive adhesive tape as described in 4 above, wherein the carbon nanotube or the carbon nanowire has an outer diameter of 0.4 to 100 nm perpendicular to the fiber length direction.

6). 4. The conductive adhesive tape according to any one of 1 to 3, wherein the fine carbon fiber is a carbon nanotube containing a fullerene or a metal fullerene.

7). The fine carbon fiber is characterized in that a structure having a discontinuous surface in which the shape of a cross section perpendicular to the axial direction of the cylinder is non-circular is introduced in a part of the length in the axial direction. The conductive adhesive tape according to any one of 1 to 3 above.

8). The fine carbon fiber is a fibrous material having a structure in which cylindrical graphene sheets are laminated in a radial direction with respect to the axial direction, and the sheet constituting the cylinder is continuous in a part of a cross section perpendicular to the axial direction of the cylinder Having a discontinuous surface that is a straight line or a curve that does not have a specific curvature over the length of a part of the axial direction, and the maximum diameter of the cross section of the cylinder is 100 nm or less, and an axis at the center of the cross section The aspect ratio having continuous hollow portions extending in the direction is 10 ⁵ or less, and a cross section perpendicular to the axis at an arbitrary position in the axial direction shows a contour line-like striped pattern by observation with an electron microscope. 8. The conductive pressure-sensitive adhesive tape as described in 7 above, which is a fine carbon fiber having a non-uniform spacing.

9. 9. The conductive adhesive tape according to any one of 1 to 8, wherein the substrate is a nonwoven fabric such as synthetic fiber or hemp.

10. 10. The conductive pressure-sensitive adhesive tape according to any one of 1 to 9, wherein release paper is attached to at least one of the conductive pressure-sensitive adhesive layers.

  According to the conductive adhesive layer of the present invention, the conductivity is solved while maintaining the adhesiveness (adhesiveness), and the above-mentioned problems are solved.

The present invention will be described below.
Thermosetting resins that can be used as the main component of the conductive adhesive tape of the present invention include general-purpose thermosetting resins [phenolic resins, amino resins (urea resins, melamine resins), epoxy resins, unsaturated polyester resins, diallyl phthalate. Resin], special thermosetting resin (polyimide resin, silicone resin), thermosetting elastomer (polyurethane, silicone elastomer, IR, BR, SBR, EPDM, IIR, CR, CHR, CHC, ACM, fluoro rubber), and composite materials (Sheet molding compound, bulk molding compound) etc. which have adhesiveness are mentioned.

  Examples of the thermoplastic resin that can be used as the main component of the conductive adhesive layer of the present invention include general-purpose thermoplastic resins (polyethylene, polypropylene, polyvinyl chloride, polystyrene, ABS resin, AS resin, polymethyl methacrylate, polyvinyl acetate, poly Vinylidene chloride, fiber-based resins, etc.), general-purpose engineering resins (nylon (polyamide), polyacetal (polyoxymethylene), polycarbonate, modified polyphenylene ether, polybutylene terephthalate, polyethylene terephthalate, etc.), and heat-resistant engineering resins (polyphenylene sulfide, polysulfone, etc.) , Polyethersulfone, polyetheretherketone, polyetherketone, polyacrylate, liquid crystal polymer, polyamideimide, polytetrafluoroethylene, etc.) Include those having tackiness.

  The thermoplastic elastomer that can be preferably used as the main component of the conductive adhesive layer of the present invention includes a thermoplastic resin (hereinafter also referred to as a resin component) and a dynamically crosslinked elastomer component, and the dynamically crosslinked elastomer. Examples thereof include a thermoplastic elastomer having a structure in which an elastomer component is dispersed in a continuous phase composed of a resin component and having adhesiveness.

  As the resin component, known thermoplastic resins that can be thermoformed can be widely used. For example, polyolefin resins (for example, high density polyethylene (HDPE), low density polyethylene (LDPE), ultra high molecular weight polyethylene (UHMWPE), Polypropylene (PP) such as isotactic polypropylene and syndiotactic polypropylene, ethylene propylene copolymer resin), polyamide resin (for example, nylon 6 (N6), nylon 66 (N66), nylon 46 (N46), nylon 11 ( N11), nylon 12 (N12), nylon 610 (N610), nylon 612 (N612), nylon 6/66 copolymer (N6 / 66), nylon 6/66/610 copolymer (N6 / 66/610) , Nylon MXD6 (MXD6), Iron 6T, nylon 6 / 6T copolymer, nylon 66 / PP copolymer, nylon 66 / PPS copolymer), polyester resin (for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene isophthalate ( Aromatic polyesters such as PEI), polyester copolymers, PET / PEI copolymers, polyarylate (PAR), polybutylene naphthalate (PBN), liquid crystal polyester, polyoxyalkylene diimidic acid / polybutylate terephthalate copolymer ), Polyether resins (for example, polyacetal (POM), polyphenylene oxide (PPO), polysulfone (PSF), polyether ether ketone (PEEK)), polynitrile resins (for example, polyacrylonitrile (P N), polymethacrylonitrile, acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer, methacrylonitrile / styrene / butadiene copolymer), polymethacrylate resin (for example, polymethyl methacrylate ( PMMA), polyethyl methacrylate), polyvinyl resins (for example, vinyl acetate (EVA), polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC)) , Vinyl chloride / vinylidene chloride copolymer, vinylidene chloride / methyl acrylate copolymer), cellulose resin (eg, cellulose acetate, cellulose acetate butyrate), fluorine resin (eg, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF) ) Polychlorofluoroethylene (PCTFE), tetrafluoroethylene / ethylene copolymer (ETFE)), imide-based resin (for example, aromatic polyimide (PI)), polyacetal, and the like that have adhesiveness can be used.

  Moreover, what is called a thermoplastic elastomer (TPE) comprised from the hard segment which consists of a crystalline thermoplastic resin, and an amorphous soft segment can also be used as a resin component. Specific examples include TPE such as polyurethane-based elastomer, polyester-based elastomer, fluoropolymer-based elastomer, and polyamide-based elastomer that have adhesiveness.

  More specifically, polyurethane elastomers include short-chain glycol diisocyanates as hard segments, long-chain polyols as soft segments, hard segments rich in urethane and urea bonds, and soft resins mainly composed of polyether. And those consisting of segments. Examples of the polyester-based elastomer include those having polybutylene terephthalate as a hard segment and long-chain polyol or polyester as a soft segment. Examples of the fluoropolymer elastomer include those having a fluororesin component as a hard segment and a fluororubber component as a soft segment. Examples of the polyamide-based elastomer include those having nylon as a hard segment and polytetramethylene glycol as a soft segment and having adhesiveness.

  Among these, in consideration of cost, friction coefficient, melting point, etc., polypropylene (PP), polyamide resin, polyester resin, polyether resin, fluorine resin, polyamide elastomer, polyurethane elastomer, polyester elastomer (COPE) And the like having a tackiness are preferably used. Moreover, these may be used individually as a resin component and may use 2 or more types together.

  Moreover, as an elastomer component, it can be set as the following elastomers and these or the arbitrary mixtures containing these, for example. Diene rubber and hydrogenated products thereof (for example, NR, IR, epoxidized natural rubber, SBR, BR (high cis BR and low cis BR), NBR, hydrogenated NBR, hydrogenated SBR), olefin rubber (for example, ethylene- Propylene-diene rubber (EPDM), ethylene propylene rubber such as EPM), maleic acid modified ethylene propylene rubber (M-EPM), IIR, isobutylene and aromatic vinyl or diene monomer copolymer, acrylic rubber (ACM), ionomer) , Halogen-containing rubber (for example, Br-IIR, CI-IIR, brominated product of isobutylene paramethylstyrene copolymer (Br-IPMS), CR, hydrin rubber (CHR), chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CM ), Maleic acid modified chlorinated poly Tylene (M-CM), silicon rubber (for example, methyl vinyl silicon rubber, dimethyl silicon rubber, methyl phenyl vinyl silicon rubber), sulfur-containing rubber (for example, polysulfide rubber), fluorine rubber (for example, vinylidene fluoride rubber, fluorine-containing vinyl ether rubber) , Tetrafluoroethylene-propylene rubber, fluorine-containing silicon rubber, fluorine-containing phosphazene rubber), urethane rubber, epichlorohydrin rubber, thermoplastic elastomer (for example, styrene elastomer, olefin elastomer, ester elastomer, urethane elastomer, polyamide) (Elastomers) and the like can be mentioned.

  Of these, olefin rubbers such as acrylic rubber (ACM) and ethylene-propylene-diene rubber (EPDM), diene rubbers or hydrogenated products thereof, halogen-containing rubbers, fluororubbers in consideration of cost, chemical resistance, etc. Of these, urethane rubber and epichlorohydrin rubber having adhesiveness are preferably used. These may be used alone or in combination of two or more.

  Among the above resins, the elastomer in the present invention has a Williams plasticity of 80 to 400, preferably 130 to 220, and the thermoplastic resin has a melt index (MI) of 2 g / 10 min. -40 g / 10 min. , Preferably 3 g / 10 min. -40 g / 10 min. The thermosetting resin has a viscosity of 0.6 to 20000 Pa. s, preferably 100 to 1000 Pa.s. s, especially 300-700 Pa.s. s is good.

  The conductive adhesive layer according to the present invention may be adhesive with a foamed resin or a foamed elastomer, and is not limited to the case where a foaming agent is used. Good.

(1) The resin or elastomer and gas are supplied to a cylinder of a first piston pump interposed in a pipe line for delivering the resin or elastomer taken out by the first pump, and the gas is supplied to the resin or elastomer. A first step of mixing, a second step of pressurizing a mixture of the resin or elastomer and the gas delivered from the first step with a second pump, and the mixed state in a pressurized state A third step of dispersing the gas in the resin or elastomer by passing the product through the dispersion pipeline, and a fourth step of foaming by discharging the mixture that has passed through the dispersion pipeline. And in the first step, the gas is supplied to a cylinder of the first piston pump, and then the resin or elastomer is supplied. , Resins or foaming process of the elastomer, characterized in that.

(2) Using a piston pump in which the piston reciprocates in the cylinder to perform a suction process and a discharge process, in the piston pump suction process, 0.1 to 5 kg / cm ² of gas is supplied into the cylinder, After the piston reaches the suction end and the suction process ends and the cylinder is filled with the gas having the adjusted pressure, the resin or elastomer is supplied into the cylinder, and the resin or elastomer is supplied. A method of mixing gas into a resin or elastomer, wherein a discharge process of the piston pump is performed after the supply is completed, and the gas and the resin or elastomer are discharged into a pipe line in the discharge process.

(3) a first step of mixing a gas having a low pressure of about atmospheric pressure into a resin or elastomer and sending the mixture at a pressure of 100 kg / cm ² or less;
A second step of pressurizing the mixture delivered from the first step to 100 kg / cm ² or more by a pump;
A third step of dispersing the gas in the resin or elastomer by passing the pressurized mixture through a dispersion line;
A fourth step of foaming by discharging the mixture that has passed through the dispersion pipe;
A method for foaming a resin or elastomer characterized by comprising:

  In particular, the pressure-sensitive adhesive used for the conductive pressure-sensitive adhesive layer in the present invention is a natural rubber-based pressure-sensitive adhesive, a butadiene-styrene copolymer rubber, a synthetic rubber-based pressure-sensitive adhesive such as polyisobutylene, poly (meth) acrylate, poly (meth) It is preferably a synthetic resin-based pressure-sensitive adhesive such as poly (meth) acrylic acid esters such as ethyl (meth) acrylate, poly (meth) acrylic acid hexyl, and poly (meth) acrylic acid 2-ethylhexyl, polyvinyl ether, and polyvinyl butyral. . These are used, for example, dissolved in a solvent. As the solvent, ethyl acetate / toluene or the like is used. A tackifier, a filler, a pigment, an anti-aging agent, a stabilizer and the like may be added to the solvent solution. As the tackifier, rosin, rosin ester, polymerized rosin ester, coumarone acid, terpene resin and the like are used.

  An acrylic pressure-sensitive adhesive is also preferably used as the pressure-sensitive adhesive. For example, (meth) acrylic acid ester such as methyl (meth) acrylate, ethyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate as a main monomer, Copolymers of monomers having functional groups such as acrylic acid, 2-hydroxyethyl (meth) acrylate, and (meth) acrylamide, and monomers that impart cohesion such as vinyl acetate, methyl acrylate, and styrene A cross-linking agent such as polyisocyanate, metal chelate, melamine resin, or epoxy resin is added and reacted. Polyisocyanates include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hydrogenated MDI, polymethylene polyphenyl polyisocyanate (polymeric MDI), tolidine isocyanate (TODI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI). Xylylene diisocyanate (XDI), hydrogenated XDI and the like are used.

Next, the nanoscale fine carbon fiber which is an essential component of the present invention will be described.
Carbon nanotubes and carbon nanowires, which are fine carbon fibers targeted by the present invention, have a unique fine structure. In particular, the carbon nanotube is a fibrous material having a structure in which graphene sheets are concentrically stacked and having a hollow structure with an outer diameter of 0.4 to 100 nm, and exhibits characteristics from a semiconductor to a metal. A. OVERLIN and M.M. ENDO first reported its existence and synthesis method [Journal of Crystal Growth vol 32, pp 335-349 (1976)], and subsequently reported that Iijima et al. Succeeded in electron micrographing of the hollow structure (Iijima, et Al Nature, vol. 354, No. 6348, pp. 56-58, 7 Nov. 1991), and Hyperion Catalysis International, Inc. have applied for a patent regarding a technique relating to fine carbon fibers as Japanese Patent Application Laid-Open No. 62-5000943. Carbon nanowires are also said to have characteristics similar to those of the carbon nanotubes.

  By adding various additives or mixtures to the synthetic resin, it is widely practiced to change the physical and chemical properties according to the application to desired ones. By adding fine carbon fibers such as carbon nanotubes or carbon nanowires, imparting semiconducting and metallic properties of these substances to the resin can revolutionize the application range of the resin. Since then, many attempts have been made.

  In general, fine carbon fibers typified by carbon nanotubes are generated in a structure in which fine fibers are entangled with each other, and it is difficult to knead them with a resin. Various methods have been proposed to overcome this. For example, Japanese Translation of PCT International Publication No. 2000-511864 proposes to facilitate mixing with a resin by adding an additive or reacting the additive with fine carbon fibers. Furthermore, it has also been attempted to produce a uniform fine carbon fiber mixed resin by mixing fine carbon fibers with resin monomers and forming a polymer around the fine carbon fibers. Is possible.

Next, the fine carbon fiber preferably used in the present invention will be described.
The fine carbon fiber preferably used in the present invention is a fibrous material having a structure in which cylindrical graphene sheets are laminated in the radial direction with respect to the axial direction, and the sheet constituting the cylinder is a cross section perpendicular to the axial direction of the cylinder. A part of the tube has a discontinuous surface that is a straight line or a curve that does not have a continuous curvature along the length of a part of the axial direction, and the maximum diameter of the cross section of the cylinder is 100 nm or less. The aspect ratio having a continuous hollow portion continuous in the axial direction at the center of the film is 10 ⁵ or less, and a cross section perpendicular to the axis at an arbitrary position in the axial direction shows a contoured stripe-like pattern by observation with an electron microscope, It is a fine carbon fiber having a non-uniform spacing between graphene sheets in cross section.

  Further, the fine carbon fiber preferably used in the present invention has at least one refraction point in the axial direction, both sides sandwiching the refraction point are linear, and the length of the straight portion is perpendicular to the axis. The cross-sectional area perpendicular to the axis on both sides of the refractive point is discontinuously changed at the refraction point, there is a portion where the graphene sheet is discontinuous, and the graphene sheet has a six-membered ring. There are not carbocyclic structures.

  Further, in the fine carbon fiber preferably used in the present invention, the cross section perpendicular to the axis at an arbitrary position in the axial direction shows a contoured stripe pattern as observed by an electron microscope, and the interval between the graphene sheets in the cross section is the entire fiber length. It has a non-graphite multilayer structure with adjacent graphene sheet layers that change due to the magnetic field, and the Magnetoresistance value takes a negative value with respect to the change in magnetic flux density. Does not have clearly. Moreover, it is a fine carbon fiber in which the maximum diameter of the cross section of the hollow portion is 10 nm or less, the variation is 2 nm or less, and the difference between the maximum value and the minimum value of the cross-sectional area is 1% or more.

In the fine carbon fiber preferably used in the present invention, amorphous carbon is deposited on the surface of the outermost layer of the fiber, the maximum thickness is 10 nm or less, and the specific surface area of the fiber is 200 m ² / g or less.

  The fine carbon fiber preferably used in the present invention is a fine carbon fiber having an outer diameter of 100 nm or less in a cross section perpendicular to the axis as produced by a CVD or CCVD method at a temperature of 1300 ° C. or less, and preferably the fiber. Further, it was obtained by processing at 3000 ° C. or lower.

  The present invention further includes a fine carbon fiber aggregate having a fiber diameter of 100 nm or less and containing 0.001% or more of the fine carbon fibers having any one or more of the structures having the above characteristics. In using the fine carbon fiber preferably used in the present invention, it is often used in the form of this aggregate.

  The fine carbon fiber preferably used in the present invention has a structure in which a discontinuous surface having a non-circular cross-sectional shape perpendicular to the axial direction of the cylinder is introduced along the length of a part of the axial direction. is there.

  Thereby, the fine carbon fiber preferably used in the present invention is difficult to bend and can give elasticity, that is, a property of returning to the original shape even after deformation. It can be easily solved. Therefore, it is difficult to form an entangled structure in the aggregated structure, and it can be easily dispersed when mixed in the matrix material.

  As described above, the resin used in the present invention may be an elastomer, a thermoplastic resin, or a thermosetting resin. In the case of a silicone resin, the silicone used As the rubber, a polysiloxane base polymer having a polymerization degree of 1000 or more, that is, a so-called millable type is preferable.

  The resin used in the present invention may be a rubber or an elastomer, and a resin that requires a vulcanizing agent for curing, such as silicone rubber, may contain a vulcanizing agent. However, if it does not contain a vulcanizing agent, it may be added before the conductive adhesive tape molding step. The timing of adding the vulcanizing agent may be any time before kneading the fine carbon fibers, during kneading or after kneading and before molding.

The conductive adhesive layer of the present invention may contain known additives in addition to fine carbon fibers typified by carbon nanotubes.
And as a carbon nanotube preferably used for this invention, it can employ | adopt combining 1 or 2 or more types of well-known various things.

  Any technique may be used to mix and disperse the nanoscale fine carbon fibers in the resin or elastomer as used in the present invention. The content of the nanoscale fine carbon fiber is preferably 1 to 30% by weight, particularly 5 to 25% by weight.

  The base material used in the present invention is a non-conductive base material such as high-quality paper such as kraft paper, synthetic paper, mirror-coated paper, non-woven fabric, polypropylene, polyethylene, polyester, or vinyl chloride.

  Moreover, as a base material used for this invention, it is a laminated base material which laminated | stacked metal foil on one or both surfaces of the plastic film base material which provided the fine hole in the whole surface, and the plastic film which provided the fine hole in the whole surface. And the diameter of the openings of the micropores on the surface of the plastic film is 1500 μm or less, the total area of the openings is 5 to 15% of the area of the surface, It is preferable that half or more of the fine holes are through holes, and the thickness of the plastic film is preferably 10 to 90 μm.

In particular, the base material used in the present invention is preferably a nonwoven fabric, such as rayon nonwoven fabric, hemp nonwoven fabric, rayon / hemp nonwoven fabric, etc., and particularly preferred nonwoven fabrics are as follows. It is a nonwoven fabric made by making paper from polyester fiber and does not use a binder, and this polyester fiber nonwoven fabric has a basis weight of 25 to 50 g / m ² and a tensile strength of 1.0 kgf / cm ² or more in both the longitudinal and transverse directions. The polyester fiber nonwoven fabric used as a base material has a tensile strength aspect ratio of 80 to 120%, and is made of a papermaking method and does not use a binder (adhesive) that bonds the fibers together. That is, it is a nonwoven fabric in which the fibers are not bonded to each other with a binder. As the polyester fiber, polyethylene terephthalate fiber is preferably used. The basis weight of the nonwoven fabric is 25 to 50 g / m ² , and the tape strength of the nonwoven fabric is preferably 1.0 kgf / cm ² or more in both the vertical direction and the horizontal direction. Further, those having a tensile strength aspect ratio of 80 to 120% are preferably used. By using a non-woven fabric having substantially the same aspect ratio of tensile strength as the base material, a tape having substantially the same aspect ratio of tensile strength can be obtained.

And as for the tensile strength of this base material, 1.3-7 kgf / cm < ² > is preferable, More preferably, it is 1.5-4 kgf / cm < ² >. If the tensile strength of the substrate is 1.3 kgf / cm ² or less, there is a risk of tearing during the peeling operation. In addition, when the tensile strength of the base material is 7 kgf / cm ² or more, the hand tearability of the tape during use is poor. And it is preferable that the tensile strength of this base material is 150% or more of the peel strength (adhesive strength) of the tape. If it is less than 150%, there is a risk that the tape may be cut or glue may be left where it is difficult to peel. Furthermore, if there are parts or directions where the tensile strength is weak in the peeling operation, tearing will occur along the parts or directions, so the ratio of the longitudinal direction and the transverse direction of the tensile strength of the tape will be 80-120%, and the direction will be as low as possible. To do. Moreover, it is preferable that there is no directionality also about the elongation at the time of the fracture | rupture of a tape, The ratio of the vertical direction of this elongation at the time of a fracture | rupture is desirably 60 to 140%.

In the present invention, the tensile strength and elongation of the substrate are values calculated as follows. That is, a sample was collected with a width of 15 mm from the longitudinal direction (machine direction; MD direction) and the lateral direction (width direction; TD direction) of the substrate. This sample was pulled using a tensile tester at a gripping interval of 180 mm and a tensile speed of 20 mm / min, and the load and the gripping interval when the tape was cut were measured. And tensile strength (kgf / cm < ² >) was computed by the type | formula of (10xp) / W (however, p is the maximum load kgf at the time of a cutting | disconnection, and W is the width mm of a test piece). The elongation (%) was calculated by the formula (l ₁ -l ₀ ) / l ₀ (where l ₀ is the initial gripping interval and l ₁ is the gripping interval at the time of cutting). The tensile strength and elongation of the nonwoven fabric of the base material are values calculated in the same manner.

  As the release paper used in the present invention, polyethylene resin is laminated to pulpy paper such as glassine paper, kraft paper, fine paper, and the laminated resin surface is subjected to release treatment such as silicone, polyethylene terephthalate film, Examples include a film-like release paper obtained by subjecting a synthetic resin film such as polypropylene to a release treatment such as silicone. Of these, it is preferable that a polyethylene terephthalate film with good surface smoothness, heat resistance and dimensional stability is subjected to a release treatment such as silicone, and a thin film having a thickness of about 16 to 38 μm is used. It is preferable because it is easy to do.

  The pressure-sensitive adhesive tape of the present invention is produced, for example, as follows. That is, a pressure-sensitive adhesive in which nanoscale fine carbon fibers are dispersed is dissolved in a solvent, and a conductive pressure-sensitive adhesive composition is prepared by adding and adding a tackifier, a filler, a pigment, an anti-aging agent, a stabilizer, and the like. . This conductive pressure-sensitive adhesive composition is coated on a release paper with a comma coater or the like, dried in a drying furnace, laminated on one side of a nonwoven fabric as a substrate, and wound up on a roll. Next, a conductive adhesive composition is coated on another release paper with a comma coater or the like, and is laminated on a surface not provided with an adhesive layer of a nonwoven fabric as a base material wound up on the roll. Thereby, a structure of release paper / conductive adhesive layer / nonwoven fabric as a substrate / conductive adhesive layer / release paper is obtained. This structure is left as it is, or one release paper is peeled off and wound up on a roll to produce a wound tape.

  The conductive adhesive tape of the present invention is an electromagnetic wave shielding material for plastic containers containing electronic devices such as computers, communication devices, amplifiers, grounding wires for electrical components, leakage current removing materials that also serve to prevent fixation and vibration, triboelectricity, etc. It can be used as a material for preventing static electricity, a weak heating element for preventing condensation and freezing.

  The invention is illustrated by the following examples.

○ Raw material A polyester fiber nonwoven fabric obtained by making paper using 100% polyethylene terephthalate fiber with a slanted wire in a single net system was used.

  On the other hand, a tackifier (disproportionated rosin glycerin ester and 100 parts by weight of a copolymer of 70 parts by weight of n-butyl acrylate, 2-ethylhexyl acrylate, 20 parts by weight of hydroxyethyl methacrylate and 10 parts by weight of methacrylic acid) Polymerized rosin ester mixed system) 5 parts by weight is added and dissolved in ethyl acetate / toluene to form a solution with a solid content of 45%. Further, polyisocyanate-based crosslinking agent (TDI) is added to 100 parts by weight of the above copolymer solution. An adhesive solution was prepared by adding 1.5 parts by weight (liquid / liquid ratio) to the parts. As a carbon nanotube (CNT) in this adhesive solution, a CNT20 prototype manufactured by Carbon Nanotech Research Institute Co., Ltd. was used, and the added amount (% by weight) of this carbon nanotube was such that the final content concentration was Addition dispersion was carried out so that it might become 5%. That is, using a three-roll kneader, kneading was repeated and kneaded to prepare a conductive adhesive composition.

This conductive adhesive composition was applied to the release paper so as to have a thickness of 65 μm on one side (when dried). Two sheets of this conductive adhesive composition-coated release paper were pressed against both sides of the polyester fiber nonwoven fabric and aged for one week to produce a double-sided conductive adhesive tape.
The physical properties and peeled state of the double-sided conductive pressure-sensitive adhesive tape produced as described above were examined. As a result, sufficient effects were observed in both conductivity and pressure-sensitive adhesiveness.

Claims (10)

In a conductive pressure-sensitive adhesive tape in which a conductive pressure-sensitive adhesive layer is provided on a tape or sheet-like base material, the base material is non-conductive, and a foamed or non-foamed adhesive resin or elastomer is a main component on both surfaces of the base material. A conductive pressure-sensitive adhesive tape comprising a conductive pressure-sensitive adhesive layer containing nanoscale fine carbon fibers. When the resin is a thermoplastic resin, the melt index (MI) is 2 g / 10 min. -40 g / 10 min. The conductive adhesive tape according to claim 1, wherein the conductive adhesive tape is a resin. The conductive adhesive tape according to claim 1, wherein the elastomer has a Williams plasticity of 80 to 400. The conductive adhesive tape according to any one of claims 1 to 3, wherein the fine carbon fiber is at least one kind or a mixture of two or more kinds of carbon nanotubes and carbon nanowires. The conductive adhesive tape according to claim 4, wherein the carbon nanotube or the carbon nanowire has an outer diameter of 0.4 to 100 nm perpendicular to the fiber length direction. The conductive pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the fine carbon fibers are carbon nanotubes containing fullerene or metal fullerene. The fine carbon fiber is characterized in that a structure having a discontinuous surface in which the shape of a cross section perpendicular to the axial direction of the cylinder is non-circular is introduced in a part of the length in the axial direction. The conductive adhesive tape according to any one of claims 1 to 3. The fine carbon fiber is a fibrous material having a structure in which cylindrical graphene sheets are laminated in a radial direction with respect to the axial direction, and the sheet constituting the cylinder is continuous in a part of a cross section perpendicular to the axial direction of the cylinder Having a discontinuous surface that is a straight line or a curve that does not have a specific curvature over the length of a part of the axial direction, and the maximum diameter of the cross section of the cylinder is 100 nm or less, and an axis at the center of the cross section The aspect ratio having continuous hollow portions extending in the direction is 10 ⁵ or less, and a cross section perpendicular to the axis at an arbitrary position in the axial direction shows a contour line-like striped pattern by observation with an electron microscope. The conductive adhesive tape according to claim 7, wherein the conductive adhesive tape is a fine carbon fiber with non-uniform spacing. The conductive adhesive tape according to claim 1, wherein the substrate is a nonwoven fabric such as synthetic fiber or hemp. The conductive adhesive tape according to claim 1, wherein release paper is attached to at least one of the conductive adhesive layers.