JP2008207404A - Conducting film and composite film having conducting film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conducting film which has excellent electroconductivity and steam barrier properties, especially, outstanding adhesion with a metallic plate, and also a conducting film which imparts corrosion resistance to the metallic material and can restrain the deterioration of a cell performance due to the increase in internal resistance of a cell or metal elution, when the film is used for the positive polar plate, negative polar plate, collector, terminal, etc. of various kinds of the cells, in the way the film is bonded with a metallic material. <P>SOLUTION: This conducting film comprises a conducting resin layer formed by mixing a thermoplastic resin with an electric conduction agent and a conducting adhesive layer formed by mixing an adhesion-loaded thermoplastic resin with the electric conduction agent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a conductive film excellent in conductivity and water vapor barrier property, and particularly excellent in adhesion to a metal plate, and a composite film composed of the conductive film and a metal.

  In the electronics field, the main characteristics required for polymer materials vary depending on the product and application, but formability, heat resistance, durability, high conductivity, corrosion resistance, adhesion to metal plates, recyclability, and electromagnetic shielding properties. It is. Examples of the resin that satisfies some of the main characteristics described above include thermosetting resins represented by epoxy resins and phenol resins, and engineering plastics represented by polyphenylene oxide, liquid crystal polymer, polyimide, polycarbonate, and the like. ing.

  In addition, the main characteristics as described above are also required for films used in the electronics field. That is, considering each application in the electronics field, one or more of the main characteristics such as formability, heat resistance, durability, high conductivity, corrosion resistance, adhesion to metal plates, recyclability, electromagnetic wave shielding, etc. Development of the film which has is requested | required.

  For example, the use of the conductive film includes a lithium battery, a silver oxide battery, an air zinc battery, a lithium ion battery, a lead storage battery, a redox battery, a paper battery, a polymer battery, and an electric double layer capacitor. In such a battery, a metal material may be used for a positive electrode plate, a negative electrode plate, a current collector, a terminal, etc., but the metal material is corroded by an electrolyte or charging / discharging conditions, and the internal resistance of the battery is increased. Battery performance degradation due to metal elution is a major problem.

To solve the above problems, a styrene-ethylene-butylene-styrene copolymer resin, a conductive agent, and an adhesive or process oil are mixed in a solution dispersed and mixed in an organic solvent to form a substrate having releasability. It has been reported that a conductive film prepared by peeling off from a substrate after coating and drying reduces the contact resistance with a polarizable electrode or an electrode plate. (For example, see Patent Documents 1 and 2)
Japanese Patent Laid-Open No. 10-4034 Japanese Patent Laid-Open No. 10-4033

  However, the conductive film described above has a problem that it is poor in adhesiveness to the metal plate, easily permeates water vapor, and is easily corroded because the metal plate is in contact with the electrolytic solution. Accordingly, an object of the present invention is to provide a conductive film having excellent water vapor barrier properties and particularly excellent adhesion to a metal plate. Further, the positive electrode plate and the negative electrode plate of various batteries are bonded to a metal material. It is an object of the present invention to provide a conductive film that imparts corrosion resistance to a metal material when used for a current collector, a terminal, and the like, and prevents an increase in internal resistance of the battery and a decrease in battery performance due to metal elution.

  This invention discovered the electroconductive film which can eliminate the above-mentioned problem, and the place made into the summary is the adhesiveness of the electroconductive resin layer formed by mixing a conductive agent with a thermoplastic resin, and a metal. It is a conductive film having at least a conductive adhesive resin layer formed by mixing a conductive agent with a thermoplastic resin.

In addition, when the conductive adhesive resin layer of the conductive film is thermally fused to the metal plate, the conductive film is peeled off from the metal plate in a 180 ° direction according to JIS K-6854-2. The peel strength is 9.8 N / 25 mm or more, the volume resistance value measured by the four deep needle method according to JIS K-7194 of the conductive film is 10 Ωcm or less, the JIS K of the conductive film -7129 The water vapor transmission rate by the B method is 10 g / (m ² · 24 hours) or less at 40 ° C. and 90% RH, according to JIS K-7194 of the conductive adhesive resin layer. The volume resistance value measured by the method is 5 Ωcm or less, and the content of the conductive agent contained in the conductive adhesive resin layer is in the range of 20 to 65% by mass with respect to the total mass of the conductive adhesive resin layer. Before being The content of the conductive agent contained in the conductive resin layer is in the range of 10 to 80% by mass with respect to the total mass of the conductive resin layer, the conductive resin layer and the conductive adhesive resin layer are A conductive resin layer, a conductive adhesive resin layer, or a conductive adhesive resin layer, a conductive resin layer, and a conductive adhesive resin layer are laminated in this order, and the metal plate is made of stainless steel, titanium, or an alloy thereof. At least one selected from the group consisting of aluminum or an alloy thereof, copper or an alloy thereof, nickel or an alloy thereof, and steel, and the conductive agent contained in the conductive adhesive resin layer selected from carbon fibers and carbon nanofibers It includes a conductive agent containing seeds, and a conductive resin layer of the conductive film is a layer formed by heating and melting.

  Moreover, this invention discovered the electroconductive composite film which can eliminate the above-mentioned problem, and the place made into the summary is the electroconductive composite film characterized by consisting of the said electroconductive film and a metal plate. is there. The conductive composite film is characterized in that the metal plate is selected from the group consisting of stainless steel, titanium or an alloy thereof, aluminum or an alloy thereof, copper or an alloy thereof, nickel or an alloy thereof, or steel.

  According to the conductive film having at least the conductive resin layer and the conductive adhesive resin layer of the present invention, it is possible to provide a conductive film having both the adhesion between the conductive film and the metal, the water vapor barrier property, and the good conductivity. Can do. In addition, according to the composite film in which the conductive film of the present invention is bonded to a metal plate, the conductive composite film has good adhesion between the conductive film and the metal plate and the water vapor barrier property of the conductive film to be bonded. It is possible to provide a conductive composite film having both corrosion resistance and good conductivity.

Hereinafter, the present invention will be described in detail.
(Conductive resin layer)
There is no restriction | limiting in particular as a thermoplastic resin used for the conductive resin layer of the conductive film which concerns on this invention. For example, polyolefin (PO) resin such as homopolymer or copolymer containing ethylene or polyolefin elastomer, amorphous polyolefin resin (APO) such as cyclic polyolefin, polystyrene (PS), acrylonitrile-butadiene-styrene copolymer Polystyrene resins such as polymer (ABS), styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), or styrene-ethylene / butylene-styrene copolymer (SEBS), styrene- Hydrogenated styrene elastomers such as ethylene / propylene-styrene copolymer (SEPS), styrene-ethylene-ethylene / propylene-styrene copolymer (SEEPS), polyvinyl chloride (PVC) resin, polyvinylidene chloride ( VDC) resin, polymethyl methacrylate (PMMA), acrylic resins such as copolymer acrylic, polyester resins such as polyethylene terephthalate (PET), nylon 6, nylon 12, polyamide (PA) resins such as copolymer nylon, polyvinyl Alcohol (PVA) resin, polyvinyl alcohol resin such as ethylene-vinyl alcohol copolymer (EVOH), polyimide (PI) resin, polyetherimide (PEI) resin, polysulfone (PS) resin, polyethersulfone (PES) Resin, polyamide imide (PAI) resin, polyether ether ketone (PEEK) resin, polycarbonate (PC) resin, polyvinyl butyral (PVB) resin, polyarylate (PAR) resin, vinylidene fluoride-tetrafluoroethylene-hexafluoro Fluorine resin such as propylene copolymer (THV), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), vinylidene fluoride (PVDF), vinyl fluoride (PVF), or an elastomer thereof, (meta) Examples include acrylate resins.

  Among the thermoplastic resins, polyolefin (PO) resin, styrene-ethylene / butylene-styrene copolymer (SEBS), styrene-ethylene / propylene-styrene copolymer (SEPS), which are excellent in water vapor barrier properties and acid resistance. ), Hydrogenated styrene elastomers such as styrene-ethylene-ethylene / propylene-styrene copolymer (SEEPS), or polyolefin elastomers, fluororesins or fluoroelastomers are preferred, among which polypropylene elastomers and fluorine The elastomer is particularly preferable because it is excellent in water vapor barrier properties and acid resistance.

The conductive agent contained in the conductive resin layer is graphite powder such as natural graphite, pyrolytic graphite, quiche graphite, etc., expanded graphite obtained by immersing the graphite powder described above in an acidic solution, and then expanded by heating, ketjen black Carbon black made by acetylene black or furnace method, carbon fiber made from polyacrylonitrile (PAN), pitch, etc., carbon nanofiber made by arc discharge method, laser deposition method, vapor phase growth method, etc. Metal carbide such as tungsten carbide, silicon carbide, zirconium carbide, tantalum carbide, titanium carbide, niobium carbide, molybdenum carbide, vanadium carbide, metal oxide such as titanium oxide, ruthenium oxide, indium oxide, chromium nitride, aluminum nitride, Molybdenum nitride, zirconium nitride, tantalum nitride, titanium nitride, gallium nitride Metal nitrides such as aluminum, niobium nitride, vanadium nitride and boron nitride, metal fibers such as iron fiber, copper fiber and stainless steel fiber, and metal powders such as titanium powder, nickel powder, tin powder, tantalum powder and niobium powder. .
Among the conductive agents, it is particularly preferable to use graphite powder, carbon black, carbon fiber, or carbon nanofiber having excellent acid resistance.

  The lower limit of the fiber diameter of the carbon nanofiber is 0.0007 μm, preferably 0.005 μm, more preferably 0.01 μm, and the upper limit is 0.5 μm, preferably 0.2 μm, more preferably 0. .15 μm. The lower limit of the fiber length is 0.1 μm, preferably 0.15 μm, more preferably 0.2 μm, and the upper limit is 30 μm, preferably 10 μm, more preferably 5 μm. This increases the conductivity and facilitates the formation of a conductive path.

  The lower limit of the content of the conductive agent in the conductive resin layer is 10% by mass, preferably 12% by mass, more preferably 15% by mass, and the upper limit is 80% by mass with respect to the total mass of the conductive resin layer. Preferably, it is 77 mass%, More preferably, it is 75 mass%. When the content of the conductive agent in the thermoplastic resin is 80% by mass or less, the resin has good fluidity and can be thinned, and the conductive resin layer has good strength. Moreover, if the content rate of the electrically conductive agent in a thermoplastic resin is 10 mass% or more, electroconductivity can fully be expressed.

(Conductive adhesive resin layer)
The thermoplastic resin used for the conductive adhesive resin layer in the conductive film according to the present invention is preferably an acid-modified thermoplastic resin. For example, acid modified polyolefin (PO) resins such as homopolymers or copolymers containing ethylene, polyolefin elastomers, amorphous polyolefin resins such as cyclic polyolefins (APO), polystyrene (PS), acrylonitrile- Polystyrene resins such as butadiene-styrene copolymer (ABS), styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene / butylene-styrene copolymer ( SEBS), hydrogenated styrene elastomers such as styrene-ethylene / propylene-styrene copolymer (SEPS), styrene-ethylene-ethylene / propylene-styrene copolymer (SEEPS), polyvinyl chloride (PVC) resin, Polyvinyl chloride (PVDC) resin, polymethyl methacrylate (PMMA), acrylic resins such as copolymer acrylic, polyester resins such as polyethylene terephthalate (PET), nylon 6, nylon 12, polyamide (PA) resins such as copolymer nylon , Polyvinyl alcohol (PVA) resin, polyvinyl alcohol resin such as ethylene-vinyl alcohol copolymer (EVOH), polyimide (PI) resin, polyetherimide (PEI) resin, polysulfone (PS) resin, polyethersulfone ( PES) resin, polyamideimide (PAI) resin, polyetheretherketone (PEEK) resin, polycarbonate (PC) resin, polyvinyl butyral (PVB) resin, polyarylate (PAR) resin, vinylidene fluoride-tetrafluoroethylene- Fluorine-based resins or elastomers such as propylene fluoride copolymer (THV), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), vinylidene fluoride (PVDF), vinyl fluoride (PVF), (meta ) Acrylate resins and the like.

  Among the thermoplastic resins used in the conductive adhesive resin layer, an acid-modified polyolefin (PO) resin, styrene-ethylene / butylene-styrene, because of its excellent adhesion to metals and acid resistance The use of a hydrogenated styrene elastomer such as a copolymer (SEBS), a styrene-ethylene / propylene-styrene copolymer (SEPS), a styrene-ethylene-ethylene / propylene-styrene copolymer (SEEPS), Among them, acid-modified SEBS is particularly preferable because it is excellent in adhesion to metals and acid resistance.

  The method for acid modification is not particularly limited, but a method of copolymerizing a maleic anhydride monomer is preferably used from the viewpoint of improving adhesiveness.

    The conductive agent contained in the conductive adhesive resin layer is preferably carbon fiber or carbon nanofiber. When carbon fiber and carbon nanofiber are used for the conductive adhesive resin layer, the carbon fiber or carbon nanofiber is exposed from the conductive adhesive resin layer, so that the contact resistance with the metal plate can be greatly reduced.

  The carbon fiber is preferably a polyacrylonitrile (PAN) -based carbon fiber or a pitch-based carbon fiber. The lower limit of the fiber diameter is 1.0 μm, preferably 5.0 μm, more preferably 10 μm, and the upper limit is 30 μm, preferably 25 μm. More preferably, the range of 20 μm is desirable. Further, the lower limit value of the fiber length is 0.03 mm, preferably 0.05 mm, more preferably 0.10 mm, the upper limit value is 10 mm, more preferably 5.0 mm, more preferably 3.0 mm. Since the number of contacts increases and a conductive path can be easily formed, it is excellent in conductivity and preferable.

  As the carbon nanofibers contained in the conductive adhesive resin layer, so-called carbon nanotubes obtained by an arc discharge method, a laser vapor deposition method, a vapor phase growth method, a liquid phase growth method, or the like can be used. Carbon nanofibers include single-type carbon tube structures that are single tubes, double-type tubes that are double tubes, and multi-type structures that are triple or more, and at least one end of the tube is closed. Also included are shapes such as a nano horn type, a cup type in which a large number of carbon network layers having a bottomless cup shape are stacked.

  The lower limit of the diameter of the carbon nanofiber is 0.0007 μm, preferably 0.05 μm, more preferably 0.01 μm, and the upper limit is 0.5 μm, preferably 0.2, μm, more preferably 0.15 μm. It is desirable that The lower limit of the length of the carbon nanofiber is 0.1 μm, preferably 0.15 μm, more preferably 0.2 μm, and the upper limit is 30 μm, more preferably 10 μm, and further preferably 5 μm. . When the diameter of the carbon nanofiber is 0.0007 μm or more and the length is 0.1 μm or more, the bulk density is small, it is difficult to scatter, the workability is good, and hygienic is preferable. Also, if the carbon nanofiber diameter is 0.5 μm or less and the length is 30 μm or less, there are many junctions between the carbon nanofibers, good electrical conductivity can be obtained, and the resistance value should be low. Can do.

  The lower limit of the content of the conductive agent contained in the conductive adhesive resin layer is 20% by mass, preferably 22% by mass, more preferably 25% by mass, with respect to the total mass of the conductive adhesive resin layer. Is 65% by mass, preferably 63% by mass, more preferably 60% by mass. If the content rate of the electrically conductive agent contained in a conductive adhesive resin layer is 20 mass% or more, favorable electroconductivity will be obtained and the contact resistance at the time of bonding to a metal plate can also be made small. On the other hand, if the content of the conductive agent contained in the conductive adhesive resin layer is 65% by mass or less, the ratio of the conductive agent is appropriate, so that sufficient peel strength can be obtained when bonded to a metal plate. preferable.

  In the conductive film according to the present invention, “resin having adhesiveness to metal” refers to a resin that can be bonded to a metal plate when thermally bonded to the metal plate. In the present invention, the adhesive strength is used as an index representing the adhesiveness, and after the conductive adhesive resin layer of the conductive film is heat-sealed to the metal plate, the metal according to JIS K-6854-2. A resin having an adhesive property of 4.9 N / 25 mm or more is defined as a peel strength when the conductive film is peeled from the plate in the 180 ° direction.

  The conductive film according to the present invention desirably has a peel strength of 9.8 N / 25 mm or more, preferably 15 N / 25 mm or more, and more preferably 20 N / 25 mm or more. When the peel strength is 9.8 N / 25 mm or more, when a composite film of a conductive film and a metal plate is used as a battery member, positional displacement hardly occurs and the battery is easy to assemble. On the other hand, the upper limit of the peel strength of the present invention is not particularly limited, but 150 N / 25 mm is sufficient when a composite film of a conductive film and a metal plate is used for a battery member or the like.

  When the conductive film according to the present invention is bonded to a metal plate, examples of the metal constituting the metal plate include stainless steel, titanium or an alloy thereof, aluminum or an alloy thereof, copper or an alloy thereof, nickel or an alloy thereof, and steel. Etc. Among these, it is preferable to use stainless steel from the viewpoint of acid resistance.

  As for the volume resistance value of the conductive film according to the present invention, the volume resistance value determined according to JIS K 7194 is 10 Ωcm or less, preferably 8 Ωcm or less, more preferably 6 Ωcm or less. When the volume resistance value of the conductive film is 10 Ωcm or less, an increase in the internal resistance of electricity can be suppressed when used as a battery member. On the other hand, the lower limit value as the volume resistance value of the conductive film according to the present invention is not particularly determined, but is preferably 0.1 Ωcm or more in consideration of materials such as a resin and a conductive material used in the present invention.

  As for the volume resistance value of the conductive adhesive resin layer, the volume resistance value obtained in accordance with JIS K 7194 is 5 Ωcm or less, preferably 3 Ωcm or less, more preferably 1 Ωcm or less. If the volume resistance value of the conductive adhesive resin layer is 5 Ωcm or less, an increase in contact resistance when bonded to a metal plate can be suppressed, and an increase in electrical internal resistance can be suppressed when used as a battery member. Can do. On the other hand, the lower limit value as the volume resistance value of the conductive resin layer according to the present invention is not particularly determined, but is preferably 0.01 Ωcm or more in consideration of materials such as the resin and conductive material used in the present invention.

The water vapor transmission rate by the JIS K-7129 B method of the conductive film according to the present invention is 10 g / (m ² · day) or less in an environment of 40 ° C. and 90% RH when the total thickness of the conductive film is 100 μm. , Preferably 8 g / (m ² · day) or less. If the water vapor transmission rate is 10 g / (m ² · day) or less, corrosion of the surface of the metal material in contact with the conductive film can be prevented, and battery performance is increased due to increase in internal resistance of the battery or metal elution. The problem can be suppressed. On the other hand, the lower limit of the conductive film according to the present invention is not particularly limited, but considering the resin film used in the present invention and the material of the conductive material, the water vapor transmission rate is 0.1 g / (m ² · day) or more. It is desirable to be.

  The conductive film according to the present invention can be mixed with additives such as an antioxidant, a tackifier, a lubricant, a thin plate crystal, and a plasticizer, as long as the effects of the present invention are not impaired.

  Examples of the antioxidant include phenols such as irganox 1010 and irganox 1076, phosphorus such as diphenylnonylphenyl phosphite, sulfur such as DLTTDP (dilauryl-3,3 thiodipropionic acid ester), and the like. Can be mentioned.

  Examples of the tackifier include rosin, hydrogenated rosin, hydrogenated rosin ester, terpene, hydrogenated terpene, terpene-phenol, petroleum resin, hydrogenated petroleum resin, styrene, isoprene. , Etc.

  Examples of the lubricant include hydrocarbons, fatty acids, esters, alcohols, and natural waxes.

  Examples of the thin plate crystal include layered viscosity minerals such as montmorillonite, carion, and talc, and graphite.

  Examples of the plasticizer include liquid paraffin, petroleum resin, paraffin wax, and the like.

  The layer configuration of the conductive film according to the present invention is not particularly limited, but from the layer configuration of conductive resin layer / conductive adhesive resin layer or conductive adhesive resin layer / conductive resin layer / conductive adhesive resin layer. It is preferable to become. By adopting the layer configuration, the adhesion with the metal can be sufficiently exhibited.

(Process for producing conductive film)
There is no restriction | limiting in particular as a manufacturing method of a conductive resin layer, The method of heat-melting resin and shape | molding a layer, The method of coating the coating material which consists of resin, and shape | molding a layer is employable. Here, examples of the molding method by heating and melting include an extrusion molding method, a calender roll molding method, an inflation molding method, a compression molding method, an injection molding method, a transfer molding method, and a blow molding method. On the other hand, as a method of forming a layer by coating a coating material, a solution (dope) melted and made fluid is poured onto a drum (casting drum) having a smooth surface or a stainless steel smooth belt and adhered. There is a method of forming a film (melt casting method) by evaporating the solvent and evaporating the solvent through a heating step. However, as a method for producing the conductive resin layer, a method for heating and melting is preferable in terms of improving the airtightness of the layer and providing good water vapor barrier properties. Furthermore, the extrusion molding method and the calender molding method are preferable molding methods in that they can be molded with good thickness accuracy from a thin film to a thick film and are excellent in productivity.

The conductive adhesive resin layer is produced by applying a liquid composition prepared by dissolving and dispersing a thermoplastic resin and a conductive agent in a solvent to a smooth surface of the support, drying it, and supporting. After forming the conductive adhesive resin layer on the body, the conductive resin layer and the conductive adhesive resin layer are arranged on at least one side of the conductive resin layer previously formed so that they face each other. For example, a method of peeling the support after integrating the conductive resin layer and the conductive adhesive resin layer is preferable.

  As the support, various known films can be used. Examples include polyester, polycarbonate, triacetyl cellulose, cellophane, polyamide, aromatic polyamide, polyimide, polyetherimide, polyphenylene sulfide, polysulfone, polyethersulfone, polypropylene, etc. May be subjected to mold release treatment with silicone or the like. Among these, a polypropylene film and a polyester film which have been release-treated with silicone are preferable from the viewpoint of easy peeling.

  Moreover, the thickness of the said support body is 5-500 micrometers, Preferably it is the range of 10-300 micrometers. If the thickness of the support is less than 5 μm, sufficient strength as a base film cannot be obtained and wrinkles are easily formed, and if it exceeds 500 μm, the waist becomes too strong and is difficult to handle and has poor workability.

  The lower limit of the temperature when the conductive adhesive resin layer of the present invention and the metal plate are thermocompression bonded is 110 ° C., preferably 130 ° C., more preferably 150 ° C., and the upper limit is 250 ° C. or less, preferably 230. ° C or lower, more preferably 210 ° C or lower. When the temperature is lower than 250 ° C., the conductive adhesive resin layer does not flow, the binder resin in the conductive adhesive resin layer does not thermally deteriorate, and the adhesion to the metal plate is exhibited. Moreover, since the binder resin in the conductive adhesive resin melts at 110 ° C. or higher, the adhesiveness with the metal plate is exhibited.

  When the conductive film according to the present invention is adhered to a metal material and used for a positive electrode plate, a negative electrode plate, a current collector, a terminal, etc. of various batteries, the metal material is given corrosion resistance, and the internal resistance of the battery is increased. It is possible to prevent a decrease in battery performance due to metal elution.

[Conductive composite film]
The use of the conductive film according to the present invention is not particularly limited, but it may be used as a composite film by being bonded to a metal plate or may be used alone as a conductive film. The use of the composite film bonded to the metal plate is not particularly limited. For example, electromagnetic shielding material, fuel cell separator, battery and capacitor electrode material, laminated battery terminal material, conductive packing material , Biological electrode materials, various sensor members, electronic component manufacturing jigs, electrode materials for electrolytic plating, and the like. In addition, the use of the conductive film alone is not particularly limited. For example, an electromagnetic wave shielding material, a current collector for a battery and a capacitor, a conductive packing material, a biological electrode material, and various sensor members And antistatic or removal films.

  The type of the metal plate used for the conductive composite film according to the present invention is not particularly limited. For example, stainless steel, titanium or an alloy thereof, aluminum or an alloy thereof, copper or an alloy thereof, nickel or an alloy thereof An alloy, steel, etc. are mentioned. Among these, it is preferable to use stainless steel, titanium, or an alloy thereof from the viewpoint of acid resistance.

  As a method of bonding with the metal plate of the conductive composite film according to the present invention, it can be bonded without any particular limitation. Examples of the bonding method include a thermocompression bonding method in which heat is applied and a lamination method using an adhesive or a primer. Among them, a method of bonding by a thermocompression bonding method that does not use an organic solvent is desirable in that it is excellent in safety and hygiene in the working environment, and further in chemical resistance at the bonding interface, and can reduce the production process.

The upper limit of the thickness of the metal plate used for the conductive composite film according to the present invention is 5 mm or less, preferably 3 mm or less, more preferably 1 mm or less, and the lower limit is 10 μm or more, preferably 15 μm or more. Preferably it is 20 micrometers or more. When the metal plate exceeds 5 mm, the weight of the metal plate becomes heavy, the handling is difficult, and the problem that the bonding with the conductive film cannot be performed easily tends to occur. On the other hand, when the metal plate is less than 10 μm, the strength of the metal plate is insufficient, it is easily broken, and a problem that it is difficult to bond the conductive plate to the conductive film is likely to occur.
[Example]
Hereinafter, although an example is described, the present invention is not limited to this.

(Preparation of conductive resin layers 1 to 6)
A thermoplastic resin and a conductive agent are mixed in a ratio shown in Table 1 with a twin screw extruder (extruder temperature 230 ° C.), and the resulting mixture is further mixed with a single screw extruder (extruder temperature 230 ° C.). The conductive resin layers 1 to 6 were produced by extruding from the die.
The thicknesses of the obtained conductive resin layers 1 to 3, 5 and 6 were all 94 μm.
Regarding the conductive resin layer 4, since the content of the conductive agent is large, it was impossible to make the film thin.
The following thermoplastic resins and conductive agents listed in Table 1 were used.
1. Polyolefin elastomer (Reactor type PP soft resin)
"Idemitsu Kosan Co., Ltd." M142E specific gravity 0.88
2. Carbon black “Lion Co., Ltd.” Ketjen Black EC600JD Specific gravity 1.5
3. Artificial graphite powder "Showa Denko Co., Ltd." UFG-30 Specific gravity 2.2
4). Carbon Nanofiber “Showa Denko Co., Ltd.” VGCF Specific gravity 2
5. Fluorine elastomer "Sumitomo 3M Co., Ltd." THV220G Specific gravity 2

(Preparation of conductive resin layer 7)
Thermoplastic resin ("Asahi Kasei Chemicals Corporation" Tuftec H1052 SEBS resin Specific gravity 0.89 MFR13g / 10min. Hardness 67 (JIS K 6253) Tensile strength 11.8MPa Elongation 700% 300% Tensile stress 2.5MPa Styrene / Ethylene / butylene ratio (wt ratio) 20/80) and carbon black (Lion Corporation) ketjen black EC600JD specific gravity 1.5) are each dispersed in cyclohexane as shown in Table 1, and the solid content concentration is 16 mass. A dispersion was prepared so as to be%.
These dispersions were coated on a base film (polypropylene film having a release treatment: thickness 50 μm) with a bar coater (“Matsuo Sangyo”), dried at 80 ° C., and the conductive resin layer 7 on the base film. Was made.
The conductive resin layer 7 was produced so that the thickness was 94 μm by performing the above coating operation a plurality of times.

[Table 1]

(Preparation of conductive adhesive resin layers 1 to 9)
Adhesive thermoplastic resin ("Asahi Kasei Chemicals Corporation" Tuftec M1943 Maleic anhydride-modified SEBS resin Specific gravity 0.90 MFR 8 g / 10 min Hardness 67 (JIS K 6253) Tensile strength 11 MPa Elongation 650% 300% Tensile stress 2.9 MPa Styrene / ethylene / butylene ratio (wt ratio) 20/80, acid value 10 mg CH ₃ ONa / g) and conductive agent are dispersed in cyclohexane as shown in Table 2, respectively, to a solid content concentration of 8% by weight. Thus, a dispersion was prepared.
As a comparative example, a thermoplastic resin having no adhesiveness (“Asahi Kasei Chemicals Corporation” Tuftec H1052 SEBS resin Specific gravity 0.89 MFR 13 g / 10 min Hardness 67 (JIS K 6253) Tensile strength 11.8 MPa Elongation 700% 300% tensile stress 2.5 MPa Styrene / ethylene / butylene ratio (wt ratio) 20/80) and conductive agent are dispersed in cyclohexane as shown in Table 2, so that the solid concentration is 8% by weight. A liquid was prepared.
These dispersions are applied on a base film (release-treated polypropylene film: thickness 50 μm) with a bar coater (“Matsuo Sangyo”), dried at 80 ° C., and a conductive adhesive resin layer on the base film. 1-9 were produced.
The conductive adhesive resin layers 1 to 9 were produced by changing the count of the bar coater so that the thickness was 3 μm.
The results obtained by peeling the conductive adhesive resin layers 1 to 9 from the base film and measuring the volume resistance are shown in Table 2.
1. Carbon Nanofiber “Showa Denko Co., Ltd.” VGCF Specific gravity 2
2. Carbon fiber “Osaka Gas Chemical Co., Ltd.” Donakabo Milled SG-249
Specific gravity 1.6

［実施例１〜１２］ (Preparation of conductive adhesive resin layer 10)
A thermoplastic resin and a conductive agent obtained by modifying maleic anhydride with a fluoroelastomer (THV220G specific gravity 2 manufactured by Sumitomo 3M Co., Ltd.) and imparting adhesive properties as shown in Table 2, respectively, MIBK (methyl isobutyl ketone) A dispersion was prepared so that the solid concentration was 8% by weight.
The dispersion is applied on a base film (polypropylene film having a release treatment: thickness 50 μm) with a bar coater (“Matsuo Sangyo”), dried at 80 ° C., and the conductive adhesive resin layer 10 is applied on the base film. Produced.
The conductive adhesive resin layer 10 was produced by changing the count of the bar coater so that the thickness of each layer was 3 μm.
The conductive adhesive resin layer 10 was peeled from the base film, and the results of measuring the volume resistance are shown in Table 2.
[Table 2]

[Examples 1 to 12]

(Preparation of conductive film)
The conductive resin layers 1, 2, 3, 6 in Table 1 and the conductive adhesive layers 1, 2, 3, 4, 10 shown in Table 2 are combined in the combinations described in Examples 1 to 12 in Table 3, It arrange | positions in order of material film / electroconductive adhesive layer / electroconductive resin layer / electroconductive adhesive layer / base film, integrated by hot press, peels off the base film, and is described in Examples 1-12 of Table 3 Conductive films 1 to 12 were prepared.
The conditions of the hot press method were a heating temperature of 80 ° C. and a pressure of 4.9 × 10 ⁶ Pa (50 kgf / cm ² ).
The thicknesses of the obtained conductive films were all 100 μm, and the volume resistance values measured from the conductive adhesive layer side and the water vapor permeability of the conductive films are shown in Table 3.

[Reference Examples 1 to 6] [Comparative Example 1]
The conductive resin layers 1, 5, and 7 shown in Table 1 and the conductive adhesive layers 1, 5, 6, 7, 8, and 9 shown in Table 2 were integrated in the same manner as in the example, and the comparative example of Table 3 Was made.
The thickness of the obtained conductive film was 100 μm, and Table 3 shows the volume resistance value measured from the conductive adhesive layer side and the water vapor transmission rate of the conductive film.

(Measurement method of water vapor transmission rate)
The water vapor transmission rate in the present invention was measured using PERMATRAN W 3/31 (manufactured by MOCON, USA) at 40 ° C. and 90% RH according to JIS K-7129 B method. Units are expressed in g / m ^2/24 hours.

(Measurement of volume resistance)
The volume resistance value in the present invention is performed as follows according to JIS K 7194, and the unit is represented by Ωcm.
1. Measuring device Loresta HP (Mitsubishi Chemical Corporation)
2. Measurement method Four-terminal four-probe method (ASP type probe)
3. Measurement applied current 100mA

(Lamination with metal plate)
The conductive films of Examples and Comparative Examples shown in Table 3 were combined with a SUS plate (thickness 0.1 mm SUS304) in the order of SUS plate / conductive film / SUS plate, and integrated by hot pressing.
The conditions of the hot press method were a heating temperature of 180 ° C. and a pressure of 2.94 × 10 ⁶ Pa (30 kgf / cm ² ).
Table 3 shows the results of measurement of peel strength when the conductive film is peeled from SUS in the 180 ° direction.

(Titanium, aluminum, rolled steel plate of Example 1)
Conductive film 1 of Example 1 shown in Table 3, titanium type 1 (0.1 mm), aluminum # 1100 (0.1 mm), rolled steel plate (0.1 mm), metal plate / conductive film / metal plate These were arranged in the order of and integrated with a hot press.
The conditions of the hot press method were a heating temperature of 180 ° C. and a pressure of 2.94 × 10 ⁶ Pa (30 kgf / cm ² ).
Table 3 shows the results of the peel strength measurement when the conductive film was peeled from the metal plate in the 180 ° direction.

(Measurement of peel strength)
The peel strength in the present invention is determined by sandwiching a metal plate in one chuck and a conductive film / SUS plate in the other chuck, and using a tensile tester (manufactured by Intesco Co., Ltd .: material tester with thermostat 201X). Was measured (JIS K-6854-2). The measurement conditions were as follows: a bonded sample having a width of 25 mm was used, the temperature was 25 ° C., T-shaped 180 ° peeling, and the peeling speed was 50 mm / min. The unit is represented by N / 25 mm.

[Table 3]

The conductive films of Examples 1 to 9 using the conductive adhesive resin layers 1 to 4 and 10 in which the mass ratio of the conductive agent contained in the conductive adhesive resin layer is in the range of 20 to 65% by mass are as follows. as shown in 3, the volume resistivity is as low as less 10Emuomegacm, excellent conductivity, moisture vapor transmission rate was superior conductivity film 10g / m ^2/24 hours or less and barrier properties.

  Furthermore, as shown in Table 3, the conductive films of Examples 1 to 9 have a peel strength of 9.8 N when the conductive film is peeled from the SUS in the 180 ° direction after being bonded to the SUS plate. / 25 mm or more, and was a conductive film excellent in adhesion to a metal plate.

  Moreover, as shown in Table 3, after bonding the conductive film 1 to the titanium plate and the aluminum plate and the copper plate, the peel strength when peeling the conductive film from the titanium plate, the aluminum plate and the copper plate in the 180 ° direction is as follows. All were 9.8N / 25mm or more, and were the electroconductive films excellent in adhesiveness with a metal plate.

  On the other hand, the conductive films of Reference Example 2 and Reference Example 4 using the conductive adhesive resin layer 6 and the conductive adhesive resin layer 8 in which the mass ratio of the conductive agent contained in the conductive adhesive resin layer is less than 20% by mass. As shown in Table 3, it was found that the water vapor permeability was low and the adhesion strength to the metal plate was high, but the volume resistance was larger than 10 mΩcm, and the conductivity was slightly inferior.

  The conductive films of Reference Example 1 and Reference Example 3 using the conductive adhesive resin layer 5 and the conductive adhesive resin layer 7 in which the mass ratio of the conductive agent contained in the conductive adhesive resin layer exceeds 65% by mass are as follows. As shown in Table 3, although excellent in conductivity and water vapor barrier properties, the peel strength when peeling the conductive film from SUS in the 180 ° direction after bonding to the SUS plate is 9. The conductive film was less than 8 N / 25 mm and slightly inferior in adhesion to the metal plate.

Further, the conductive film of Reference Example 5 using the conductive resin layer 7 prepared by casting the conductive resin layer is excellent in adhesion and conductivity as shown in Table 3, The water vapor transmission rate was 10 g / m 2/24 hours or more, and the conductive film was slightly inferior in water vapor barrier properties.
Further, the conductive film of Reference Example 6 using the conductive resin layer 5 in which the mass ratio of the conductive agent in the conductive resin layer is 10% by mass or less is excellent in adhesiveness and water vapor barrier property, but volume It was found that the resistance was larger than 10 mΩcm and the conductivity was slightly inferior.

  Further, the conductive film of Comparative Example 1 using the conductive adhesive resin layer 9 using SBES which is not acid-modified is excellent in conductivity and water vapor barrier property as shown in Table 3, but is in a metal plate. Does not adhere.

  As described above, according to the embodiments of the present invention, it is possible to provide a conductive film having excellent conductivity and water vapor barrier property, particularly excellent adhesion to a metal plate, and further bonded to a metal material for various batteries and capacitors. When used for a positive electrode plate, a negative electrode plate, a current collector, a terminal, etc., it is possible to impart corrosion resistance to the metal material and prevent an increase in the internal resistance of the battery or a decrease in battery performance due to metal elution.

Claims (13)

A conductive material comprising at least a conductive resin layer formed by mixing a conductive agent with a thermoplastic resin, and a conductive adhesive resin layer formed by mixing a conductive agent with a thermoplastic resin having adhesiveness to a metal. Sex film. Peel strength when the conductive adhesive resin layer of the conductive film is thermally fused to the metal plate and then the conductive film is peeled from the metal plate in the 180 ° direction in accordance with JIS K-6854-2. The conductive film according to claim 1, wherein is 9.8 N / 25 mm or more. 3. The conductive film according to claim 1, wherein the conductive film has a volume resistance value of 10 Ωcm or less as measured by a four deep needle method according to JIS K-7194. The water vapor transmission rate according to JIS K-7129 B method of the conductive film is 10 g / (m ² · 24 hours) or less under 40 ° C and 90% RH. Conductive film. The conductive film according to any one of claims 1 to 4, wherein the conductive adhesive resin layer has a volume resistance value of 5 Ωcm or less measured by a four-deep needle method according to JIS K-7194. The content of the conductive agent contained in the conductive adhesive resin layer is in the range of 20 to 65% by mass with respect to the total mass of the conductive adhesive resin layer. Sex film. The conductivity according to any one of claims 1 to 6, wherein a content of the conductive agent contained in the conductive resin layer is in a range of 10 to 80 mass% with respect to a total mass of the conductive resin layer. the film. The conductive resin layer and the conductive adhesive resin layer are laminated in the order of the conductive resin layer and the conductive adhesive resin layer, or the conductive adhesive resin layer, the conductive resin layer, and the conductive adhesive resin layer in this order. The conductive film according to any one of claims 1 to 7. 9. The metal plate according to claim 2, wherein the metal plate is selected from the group consisting of stainless steel, titanium or an alloy thereof, aluminum or an alloy thereof, copper or an alloy thereof, nickel or an alloy thereof, and steel. The conductive film as described in the item. The conductive film according to any one of claims 1 to 9, wherein the conductive agent contained in the conductive adhesive resin layer is a conductive agent containing at least one selected from carbon fibers and carbon nanofibers. The conductive film according to claim 1, wherein the conductive resin layer of the conductive film is a layer formed by heating and melting. A conductive composite film comprising the conductive film according to any one of claims 1 to 11 and a metal plate. The conductive composite according to claim 12, wherein the metal plate is selected from the group consisting of stainless steel, titanium or an alloy thereof, aluminum or an alloy thereof, copper or an alloy thereof, nickel or an alloy thereof, or steel. the film.