WO2015033697A1 - Conductive aramid paper and method for producing same - Google Patents

Conductive aramid paper and method for producing same Download PDF

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Publication number
WO2015033697A1
WO2015033697A1 PCT/JP2014/069610 JP2014069610W WO2015033697A1 WO 2015033697 A1 WO2015033697 A1 WO 2015033697A1 JP 2014069610 W JP2014069610 W JP 2014069610W WO 2015033697 A1 WO2015033697 A1 WO 2015033697A1
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WO
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Prior art keywords
aramid
conductive
paper
aramid paper
fiber
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PCT/JP2014/069610
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French (fr)
Japanese (ja)
Inventor
成瀬　新二
竜士 藤森
千尋 近藤
建介 富岡
好博 岩崎
小林　義弘
Original Assignee
デュポン帝人アドバンスドペーパー株式会社
ウラセ株式会社
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Application filed by デュポン帝人アドバンスドペーパー株式会社, ウラセ株式会社 filed Critical デュポン帝人アドバンスドペーパー株式会社
Priority to JP2015535379A priority Critical patent/JP6437439B2/en
Priority to CN201480049041.8A priority patent/CN105556032A/en
Priority to KR1020167006246A priority patent/KR102180217B1/en
Publication of WO2015033697A1 publication Critical patent/WO2015033697A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/12—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of paper or cardboard
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/14—Layered products comprising a layer of metal next to a fibrous or filamentary layer
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
    • D21H13/10—Organic non-cellulose fibres
    • D21H13/20—Organic non-cellulose fibres from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H13/26—Polyamides; Polyimides
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
    • D21H13/36—Inorganic fibres or flakes
    • D21H13/46—Non-siliceous fibres, e.g. from metal oxides
    • D21H13/50—Carbon fibres
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H19/00—Coated paper; Coating material
    • D21H19/02—Metal coatings
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/02—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of metals or alloys
    • H01B1/026—Alloys based on copper
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/24—Conductive material dispersed in non-conductive organic material the conductive material comprising carbon-silicon compounds, carbon or silicon
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00—Screening of apparatus or components against electric or magnetic fields
    • H05K9/0073—Shielding materials
    • H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
    • H05K9/0088—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising a plurality of shielding layers; combining different shielding material structure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
    • B32B2262/02—Synthetic macromolecular fibres
    • B32B2262/0261—Polyamide fibres
    • B32B2262/0269—Aromatic polyamide fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
    • B32B2262/10—Inorganic fibres
    • B32B2262/106—Carbon fibres, e.g. graphite fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/20—Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
    • B32B2307/202—Conductive
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/20—Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
    • B32B2307/212—Electromagnetic interference shielding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/30—Properties of the layers or laminate having particular thermal properties
    • B32B2307/306—Resistant to heat
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
    • B32B2307/54—Yield strength; Tensile strength
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/732—Dimensional properties
    • B32B2307/734—Dimensional stability
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2605/00—Vehicles

Definitions

  • the present invention relates to a conductive aramid paper for electromagnetic wave shielding and a method for producing the same.
  • electromagnetic wave shielding materials are being developed as one of the means for protecting against electromagnetic waves.
  • a lightweight and flexible fiber for example, a woven or knitted fabric such as a woven fabric made of a synthetic polymer fiber is used.
  • means for forming a metal film on the fiber include vacuum deposition, sputtering, and electroless plating. Fabrics woven with fibers coated with metal as described above have problems that it is difficult to produce a thin fabric, shape stability is low, and workability is not good.
  • aramid paper is widely used as an electrical insulating material for the aforementioned rotating machines (generators, motors), transformers, and electrical / electronic equipment as an electrical insulator and thin-leaf structure material. It has been studied so far to impart a certain degree of conductivity to paper and use it as an electric field relaxation material.
  • Japanese Patent Application Laid-Open Nos. 51-47103 and 57-115702 disclose paper using aramid fibrids and carbon fibers or metal fibers.
  • JP 2008-542557 A discloses conductive aramid paper composed of short aramid fibers, aramid fibrids, and conductive fillers such as carbon fibers.
  • none of them are intended for the electromagnetic wave shielding material as described above, so that they are not satisfactory in terms of conductivity, particularly surface resistance and resistance in the thickness direction which are important as electromagnetic wave shielding characteristics.
  • An object of the present invention is to provide conductive aramid paper having high heat resistance and excellent electromagnetic wave shielding characteristics and workability.
  • the present inventors have found that the above problems can be solved by forming a metal layer on the surface of aramid paper composed of aramid short fibers, aramid fibrids and conductive fillers.
  • the headline and the present invention were completed. That is, the first invention of the present application has a metal layer on the surface of an aramid paper containing an aramid short fiber, an aramid fibrid and a conductive filler, and a resistance value in the thickness direction is 0.01 to 0.10 ⁇ ⁇ cm 2 .
  • a conductive aramid paper is provided.
  • the second invention of the present application provides a conductive aramid paper having a thickness of 20 to 100 ⁇ m in the conductive aramid paper according to the first invention.
  • a third invention of the present application provides a conductive aramid paper according to the first or second invention, wherein the aramid constituting the aramid short fiber and the aramid fibrid is polymetaphenylene isophthalamide. It is.
  • a fourth invention of the present application provides a conductive aramid paper according to any one of the first to third inventions, wherein the conductive filler is carbon fiber.
  • the fifth invention of the present application is a mixture of aramid short fibers, aramid fibrids and conductive fillers in water, sheeted by a wet papermaking method, and hot-pressed the obtained sheet between a pair of metal rolls, A method for producing a conductive aramid paper according to any one of the first to fourth inventions including plating is provided.
  • the present invention will be described in detail.
  • aramid means a linear polymer compound in which 60% or more of amide bonds are directly bonded to an aromatic ring.
  • examples of such aramids include polymetaphenylene isophthalamide and copolymers thereof, polyparaphenylene terephthalamide and copolymers thereof, and copolyparaphenylene 3,4'-diphenyl ether terephthalamide.
  • These aramids are industrially produced by, for example, a solution polymerization method by a condensation reaction with an aromatic acid dichloride and an aromatic diamine, a two-step interfacial polymerization method, etc., and can be obtained as a commercial product.
  • the present invention is not limited to this.
  • polymetaphenylene isophthalamide is preferably used because it has good molding processability, flame retardancy, heat resistance and the like.
  • aramid short fiber examples include those obtained by cutting a fiber made of aramid into a predetermined length, and examples of such a fiber include “Teijin Conex (registered trademark)” by Teijin Limited. ) "," Technora (registered trademark) “, DuPont” Nomex (registered trademark) “,” Kevlar (registered trademark) “, Teijin Aramid” Twaron (registered trademark) " Although what can be mentioned is mentioned, it is not limited to these.
  • the aramid short fibers can preferably have a fineness within a range of 0.05 dtex or more and less than 25 dtex.
  • a fiber having a fineness of less than 0.05 dtex is not preferable because it tends to cause aggregation in the production by a wet method (described later), and a fiber having a fineness of 25 dtex or more is too large in diameter.
  • the density is 1.4 g / cm 3 in the shape, when the diameter is 45 ⁇ m or more, there may be inconveniences such as a decrease in aspect ratio, a reduction in mechanical reinforcement effect, and aramid paper uniformity failure.
  • the uniformity defect of the conductive aramid paper occurs, there is a possibility that the conductivity of the conductive aramid paper varies and the required electromagnetic shielding function may not be sufficiently exhibited.
  • the length of the aramid short fiber can be selected from a range of 1 mm or more and less than 25 mm.
  • the length of the short fiber is smaller than 1 mm, the mechanical properties of the conductive aramid paper are deteriorated.
  • those having a length of 25 mm or more are “entangled” and “bound” when the conductive aramid paper is manufactured by the wet method described later. This is not preferable because it tends to cause defects.
  • the aramid fibrid used in the present invention is a film-like fine particle made of aramid and may be called aramid pulp.
  • Examples of the production method include those described in JP-B-35-11851, JP-B-37-5732, and the like.
  • aramid fibrids have paper-making properties like ordinary wood (cellulose) pulp, it can be formed into a sheet by a paper machine after being dispersed in water.
  • a so-called beating process can be performed for the purpose of maintaining quality suitable for papermaking. This beating process can be performed by a disk refiner, a beater, or other papermaking raw material processing equipment that exerts a mechanical cutting action.
  • the shape change of the fibrid can be monitored with the freeness as defined in JIS P8121.
  • the freeness of the aramid fibrid after the beating treatment is preferably in the range of 10 to 300 cm 3 (Canadian Standard Freeness).
  • the strength of the sheet formed therefrom may be reduced.
  • the utilization efficiency of the mechanical power to be input becomes small, the processing amount per unit time is often reduced, and further refinement of the fibrid is reduced. Since it proceeds too much, the so-called binder function is likely to deteriorate. Therefore, no particular advantage is recognized even when trying to obtain a freeness smaller than 10 cm 3 .
  • the conductive filler used in the present invention has a wide range of conductivity from a conductor having a volume resistance of about 10 ⁇ 1 ⁇ ⁇ cm or less to a semiconductor having a volume resistance of about 10 ⁇ 1 to 10 8 ⁇ ⁇ cm.
  • Examples thereof include fibrous or fine particles (powder or flakes).
  • Examples of such conductive fillers include materials having uniform conductivity such as metal fibers, carbon fibers, and carbon black, or conductive materials and non-conductive materials such as metal plating fibers, metal powder mixed fibers, and carbon black mixed fibers.
  • the present invention is not limited to these materials. Of these, carbon fibers are preferably used in the present invention.
  • the carbon fiber used in the present invention is preferably carbon fiber obtained by firing a fibrous organic material at a high temperature in an inert atmosphere.
  • carbon fibers are broadly divided into those obtained by firing polyacrylonitrile (PAN) fibers and those obtained by firing pitch after spinning. And these can also be used in the present invention.
  • PAN polyacrylonitrile
  • Prior to firing it is also possible to carry out an oxidative crosslinking treatment using oxygen or the like to prevent fusing during firing.
  • the fineness of the carbon fiber used in the present invention is preferably in the range of 0.5 to 10 dtex.
  • the fiber length is selected from the range of 1 mm to 20 mm.
  • the conductive filler it is more preferable to use a material having high conductivity and exhibiting good dispersion in the wet papermaking method described later.
  • a carbon fiber it is preferable to select a carbon fiber having higher strength and less embrittlement.
  • the conductive aramid paper of the present invention is characterized by having a metal layer on the surface of the aramid paper containing the aramid short fiber, the aramid fibrid and the conductive filler.
  • the content of short aramid fibers in the total weight of the conductive aramid paper of the present invention before forming the metal layer is preferably 5 to 60% by weight, more preferably 10 to 55% by weight, and still more preferably 20 to 50% by weight.
  • the present invention is not limited to this.
  • the content of aramid short fibers when the content of aramid short fibers is less than 5% by weight, the mechanical strength of the conductive aramid paper tends to decrease, and when it exceeds 60% by weight, the content of aramid fibrids decreases and the mechanical strength also decreases. It's easy to do.
  • the content of the aramid fibrid in the total weight of the conductive aramid paper of the present invention before forming the metal layer is preferably 30 to 80% by weight, more preferably 35 to 70% by weight, still more preferably 40 to 65% by weight.
  • the present invention is not limited to this.
  • the content of the conductive filler in the total weight of the conductive aramid paper of the present invention before forming the metal layer is preferably 1 to 30% by weight, more preferably 3 to 30% by weight.
  • the content of the conductive filler is less than 1% by weight, it is difficult to obtain the desired conductivity.
  • the aramid paper may also contain fibrillated aramid.
  • Examples of the metal material used for forming the metal layer include gold, silver, copper, zinc, nickel, and alloys thereof. Copper and nickel are preferable in consideration of conductivity and manufacturing cost, but may be selected in consideration of electromagnetic shielding properties and durability, and are not particularly limited.
  • the content of the metal layer formed on the surface of the conductive aramid paper of the present invention is preferably in the range of 10 to 20 g / m 2 on average. If the amount of the metal layer is smaller than this range, sufficient conductivity may not be obtained. Conversely, if the amount of the metal layer is larger than this range, the cost may increase.
  • the metal layer is appropriately formed by, for example, the resistance value in the thickness direction of the aramid paper measured using a resistance meter. Specifically, a value obtained by multiplying the effective resistance value obtained by the resistance meter measurement by the contact area with the electrode is used as a resistance value in the thickness direction, and the value is within a range of 0.01 to 0.10 ⁇ ⁇ cm 2. It can be said that “a continuous metal layer is appropriately formed on the surface and inside”. If the resistance value in the thickness direction is in the range of 0.01 ⁇ ⁇ cm 2 to 0.10 ⁇ ⁇ cm 2 , a conductive aramid paper that is lightweight and has sufficient electromagnetic shielding properties is provided.
  • the resistance value in the thickness direction is preferably 0.01 ⁇ ⁇ cm 2 to 0.07 ⁇ ⁇ cm 2 , more preferably 0.01 ⁇ ⁇ cm 2 to 0.04 ⁇ ⁇ cm 2 .
  • the thickness of the conductive aramid paper is not particularly limited, but in general, it preferably has a thickness in the range of 20 ⁇ m to 100 ⁇ m, more preferably 25 to 80 ⁇ m.
  • the basis weight of the conductive aramid paper is preferably 10 to 110 g / m 2 .
  • the conductive aramid paper of the present invention described above is generally plated after the above-mentioned aramid short fibers, aramid fibrids and conductive filler are mixed and then sheeted, and hot pressed between a pair of metal rolls. It can be manufactured by a processing method. Specifically, for example, (i) after aramid short fibers, aramid fibrids and conductive fillers are dry blended, a sheet is formed using an air stream and hot pressed between a pair of metal rolls.
  • Aramid short fibers, aramid fibrids and conductive fillers are dispersed and mixed in a liquid medium, and then discharged onto a liquid-permeable support, such as a net or a belt.
  • a method of forming a metal layer after the liquid is removed and dried and hot-pressed between a pair of metal rolls can be applied.
  • a method of forming a metal layer after forming into a sheet by a so-called wet papermaking method using water as a medium and hot pressing between a pair of metal rolls is preferably selected.
  • a single or mixture aqueous slurry of aramid short fibers, aramid fibrids, and conductive fillers is fed to a paper machine and dispersed, followed by dehydration, squeezing and drying operations.
  • a winding method is used.
  • the paper machine for example, a long paper machine, a circular paper machine, an inclined paper machine, a combination paper machine combining these, and the like can be used.
  • Additives such as dispersibility improvers, antifoaming agents, and paper strength enhancers can be used as necessary during wet papermaking, and if the conductive filler is in the form of particles, acrylic A resin, a fixing agent, a polymer flocculant, and the like may be added, but care must be taken in the use so as not to hinder the purpose of the present invention.
  • the conductive aramid paper of the present invention includes other fibrous components, such as polyphenylene sulfide fiber, polyether ether ketone fiber, cellulosic fiber, polyvinyl, in addition to the above components, within the range not impairing the object of the present invention.
  • additives such as alcohol fiber, polyester fiber, polyarylate fiber, liquid crystal polyester fiber, polyimide fiber, polyamideimide fiber, polyparaphenylene benzobisoxazole fiber, inorganic fiber such as glass fiber, rock wool, boron fiber it can.
  • organic fibers such as alcohol fiber, polyester fiber, polyarylate fiber, liquid crystal polyester fiber, polyimide fiber, polyamideimide fiber, polyparaphenylene benzobisoxazole fiber, inorganic fiber such as glass fiber, rock wool, boron fiber it can.
  • seat obtained in this way can improve mechanical strength by carrying out a hot-pressure process at high temperature and high pressure between a pair of flat plates or between metal rolls, for example.
  • the conditions of the hot pressing process can be exemplified, for example, within the range of a temperature of 100 to 400 ° C. and a linear pressure of 50 to 1000 kg / cm when a metal roll is used.
  • the characteristics of the conductive aramid paper of the present invention In order to obtain a high shielding characteristic, the roll temperature is preferably 330 ° C. or higher, more preferably 330 ° C. to 380 ° C.
  • the linear pressure is preferably 50 to 500 kg / cm.
  • the temperature is higher than the glass transition temperature of the meta-type aramid and close to the crystallization temperature of the meta-type aramid, not only the mechanical strength is improved by hot pressing at the temperature, but also the conductive aramid paper is used. By firmly adhering the constituent materials, resistance in the thickness direction can be reduced.
  • the above-mentioned hot pressing may be performed a plurality of times, and depending on the application, it does not require excessive space saving and may require a thickness exceeding 100 ⁇ m. A plurality of sheet-like materials obtained by the above-described method may be superposed to perform hot pressing.
  • Examples of a method for forming a metal layer on the surface of the sheet thus obtained include a vacuum deposition method, a sputtering method, an electroless plating method, and the like. From the viewpoint, the electroless plating method is particularly preferable. Further, in order to increase the amount of metal, it is possible to perform a surface treatment before forming the metal layer. Examples of the surface treatment include UV irradiation surface treatment, plasma surface treatment, corona surface treatment, electron beam irradiation surface treatment, ion beam irradiation surface treatment, resin processing, and surface treatment by liquid immersion. It is not something.
  • the conductive aramid paper of the present invention has (1) conductivity, (2) heat resistance and flame resistance, (3) high shape stability, and (4) good. It has excellent characteristics such as having excellent processability, and can be suitably used as an electromagnetic shielding material for electric and electronic devices, particularly electronic devices in hybrid cars and electric vehicles.
  • the present invention will be described more specifically with reference to examples. These examples are merely illustrative and are not intended to limit the content of the present invention.
  • a polymetaphenylene isophthalamide fibrid was manufactured using a pulp particle manufacturing apparatus (wet precipitator) composed of a combination of a stator and a rotor described in JP-A-52-15621. This was treated with a beating machine, and the length weighted average fiber length was adjusted to 0.9 mm (freeness 200 cm 3 ).
  • a meta-aramid fiber Nomex (registered trademark), single yarn fineness 2.2 dtex) manufactured by DuPont was cut into a length of 6 mm (hereinafter referred to as “aramid short fiber”) to obtain a papermaking raw material.
  • Examples 1 to 3 Meta-aramid fibrids, meta-aramid short fibers and carbon fibers prepared as described above (manufactured by Toho Tenax Co., Ltd., fiber length 3 mm, single fiber diameter 7 ⁇ m, fineness 0.67 dtex, volume resistivity 1.6 ⁇ 10 ⁇ 3 ⁇ ⁇ cm) were dispersed in water to prepare slurry. This slurry was mixed so that meta-aramid fibrids, meta-aramid short fibers, and carbon fibers would have the blending ratios shown in Table 1, and processed with a tappy hand machine (cross-sectional area of 325 cm 2 ) to form a sheet. Was made.
  • Example 4 A sheet (obtained by the same method as in Example 1) was hot-pressed at a temperature of 350 ° C. and a linear pressure of 150 kg / cm with a pair of metal calender rolls, and a metal ( A copper-nickel alloy) layer was formed to obtain conductive aramid paper. Table 1 shows main characteristic values of the conductive aramid paper thus obtained.
  • a metal (copper-nickel alloy) layer was formed on the surface of the obtained sheet by electroless plating to obtain conductive aramid paper.
  • Table 2 shows the main characteristic values of the conductive aramid paper thus obtained.
  • (Comparative Example 3) The meta-aramid fibrids and meta-aramid short fibers prepared as described above were each dispersed in water to prepare a slurry. The slurry was mixed so that the meta-aramid fibrids and the meta-aramid short fibers had a blending ratio shown in Table 2, and processed with a tappy hand machine (cross-sectional area of 325 cm 2 ) to produce a sheet.
  • a metal (copper-nickel alloy) layer was formed by electroless plating on the surface of the sheet obtained by hot-pressing the obtained sheet with a pair of metal calender rolls at a temperature of 330 ° C. and a linear pressure of 150 kg / cm.
  • a conductive aramid paper was obtained.
  • Table 2 shows the main characteristic values of the conductive aramid paper thus obtained.
  • the slurry was mixed so that the meta-aramid fibrids and the meta-aramid short fibers had a blending ratio shown in Table 2, and processed with a tappy hand machine (cross-sectional area of 325 cm 2 ) to produce a sheet.
  • a metal (copper-nickel alloy) layer was formed on the surface of the obtained sheet by a conventionally known electroless plating method to obtain conductive aramid paper.
  • Table 2 shows the main characteristic values of the conductive aramid paper thus obtained.
  • Comparative Example 3 is a sheet after hot pressing
  • the conductive aramid papers of Examples 1 to 4 which are products of the present invention, exhibited excellent characteristics in terms of surface resistivity, thickness direction resistance, shape stability, and heat resistance. Moreover, when the electromagnetic shielding performance of the conductive aramid paper of Example 1 was measured, as shown in Table 4, it showed excellent shielding performance. On the other hand, as shown in Table 2, the conductive aramid papers of Comparative Examples 1 to 5 both have high surface resistivity and thickness direction resistance, and are not suitable as the intended electromagnetic shielding material. It turns out that it is enough.
  • Comparative Example 6 has low heat resistance and low shape stability, so it is not suitable as an electromagnetic shielding material with high heat resistance that can withstand the heat generation of a conductor due to high-frequency, high-current flow, such as a hybrid car or an electric vehicle. It was suggested that it was sufficient. Therefore, it is useful as an electromagnetic shielding material for electric and electronic equipment, especially hybrid cars and electronic equipment in electric cars, etc., and has high conductivity and high heat resistance and conductive aramid having excellent shape stability, workability and mechanical strength. In order to obtain paper, it has been found that it is effective to use the conductive aramid paper exemplified in the above examples.

Abstract

The present invention provides conductive aramid paper which has a metal layer on the surface of aramid paper that contains aramid short fibers, aramid fibrids and a conductive filler. This conductive aramid paper has a resistance of 0.01-0.10 Ω/cm2 in the thickness direction.

Description

導電性アラミド紙及びその製造方法Conductive aramid paper and manufacturing method thereof
　本発明は、電磁波シールド用導電性アラミド紙及びその製造方法に関する。 The present invention relates to a conductive aramid paper for electromagnetic wave shielding and a method for producing the same.
　高度情報化社会の発展、マルチメディア社会の到来により、電子機器から発生する電磁波が他の機器に対して、また人体に対して悪影響を及ぼす電磁波障害が、大きな社会問題となりつつある。電磁波環境がますます悪化していく中、電磁波に対する防御手段の１つとして、電磁波シールド材が開発されている。従来より、電磁波シールド材料として、軽量で柔軟性のある繊維、例えば合成高分子繊維からなる織物等の織編物に金属被膜を付与したものが使用されている。繊維に金属被膜を形成する手段としては、真空蒸着法、スパッタリング法および無電解めっき法等がある。上記したような金属で被覆された繊維で織成された織物は、薄いものが作製し難く、形状安定性が低く、加工性が良くないという問題があった。
　また、ハイブリッドカー、電気自動車社会の到来により、モータ、インバータの小型化、軽量化が進み、インバータから電気モータへ高周波大電流が流れることによる導線の発熱に耐えうる耐熱性の高い電磁波シールド材料が求められている。特に高電圧が付加される大型回転機などの電気・電子機器においては、機器の温度上昇も大きくなるため、耐熱性の高い材料が求められる。 With the development of a highly information-oriented society and the arrival of a multimedia society, electromagnetic interference that electromagnetic waves generated from electronic devices adversely affect other devices and the human body is becoming a major social problem. As the electromagnetic wave environment gets worse and worse, electromagnetic wave shielding materials are being developed as one of the means for protecting against electromagnetic waves. Conventionally, as an electromagnetic shielding material, a lightweight and flexible fiber, for example, a woven or knitted fabric such as a woven fabric made of a synthetic polymer fiber is used. Examples of means for forming a metal film on the fiber include vacuum deposition, sputtering, and electroless plating. Fabrics woven with fibers coated with metal as described above have problems that it is difficult to produce a thin fabric, shape stability is low, and workability is not good.
In addition, with the advent of the hybrid car and electric vehicle society, motors and inverters have become smaller and lighter, and a highly heat-resistant electromagnetic shielding material that can withstand the heat generated by the high-frequency current flowing from the inverter to the electric motor. It has been demanded. In particular, in an electric / electronic device such as a large rotating machine to which a high voltage is applied, the temperature rise of the device is increased, and thus a material having high heat resistance is required.
　一方、電気絶縁物や薄葉構造材料として高耐熱性のアラミド紙が、前述の回転機（発電機、電動機）、変圧器分野および電気・電子機器の電気絶縁材料として広く用いられており、このアラミド紙にある程度の導電性を付与して電界緩和材料として用いることもこれまでに検討されてきた。
　特開昭５１－４７１０３号公報及び特開昭５７－１１５７０２号公報には、アラミドファイブリッドと、炭素繊維または金属繊維を使用した紙が開示されている。また、特表２００８－５４２５５７号公報には、アラミド短繊維、アラミドファイブリッドと、炭素繊維などの導電性フィラーから構成された導電性アラミド紙が開示されている。しかしながらいずれも上記のような電磁波シールド材料を目的としていないため、導電性、特に電磁波シールド特性として重要な関係のある表面抵抗、厚み方向の抵抗の点で満足するものではない。 On the other hand, highly heat-resistant aramid paper is widely used as an electrical insulating material for the aforementioned rotating machines (generators, motors), transformers, and electrical / electronic equipment as an electrical insulator and thin-leaf structure material. It has been studied so far to impart a certain degree of conductivity to paper and use it as an electric field relaxation material.
Japanese Patent Application Laid-Open Nos. 51-47103 and 57-115702 disclose paper using aramid fibrids and carbon fibers or metal fibers. JP 2008-542557 A discloses conductive aramid paper composed of short aramid fibers, aramid fibrids, and conductive fillers such as carbon fibers. However, none of them are intended for the electromagnetic wave shielding material as described above, so that they are not satisfactory in terms of conductivity, particularly surface resistance and resistance in the thickness direction which are important as electromagnetic wave shielding characteristics.
　本発明は、耐熱性が高く、電磁波シールド特性と加工性に優れた導電性アラミド紙を提供することを目的とする。 An object of the present invention is to provide conductive aramid paper having high heat resistance and excellent electromagnetic wave shielding characteristics and workability.
　本発明者らは、上記課題を解決するため鋭意検討した結果、アラミド短繊維、アラミドファイブリッド及び導電性フィラーからなるアラミド紙の表面に金属層を形成することにより、上記の課題を解決できることを見出し、本発明を完成するに至った。
　すなわち、本願の第１の発明は、アラミド短繊維、アラミドファイブリッド及び導電性フィラーを含むアラミド紙の表面に金属層を有する、厚み方向の抵抗値が０．０１～０．１０Ω・ｃｍ2である、導電性アラミド紙を提供するものである。
　本願の第２の発明は、上記第１の発明に従う導電性アラミド紙において、厚みが２０～１００μｍである導電性アラミド紙を提供するものである。
　本願の第３の発明は、上記第１または第２の発明に従う導電性アラミド紙において、アラミド短繊維及びアラミドファイブリッドを構成するアラミドがポリメタフェニレンイソフタルアミドである導電性アラミド紙を提供するものである。
　本願の第４の発明は、上記第１～第３のいずれかの発明に従う導電性アラミド紙において、導電性フィラーが炭素繊維である導電性アラミド紙を提供するものである。
　本願の第５の発明は、アラミド短繊維、アラミドファイブリッド及び導電性フィラーを水中で混合し、湿式抄造法でシート化し、得られたシートを一対の金属製ロール間にて熱圧加工し、メッキ加工することを含む上記第１～第４のいずれかの発明に従う導電性アラミド紙の製造方法を提供するものである。
　以下、本発明について詳細に説明する。 As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by forming a metal layer on the surface of aramid paper composed of aramid short fibers, aramid fibrids and conductive fillers. The headline and the present invention were completed.
That is, the first invention of the present application has a metal layer on the surface of an aramid paper containing an aramid short fiber, an aramid fibrid and a conductive filler, and a resistance value in the thickness direction is 0.01 to 0.10 Ω · cm 2 . A conductive aramid paper is provided.
The second invention of the present application provides a conductive aramid paper having a thickness of 20 to 100 μm in the conductive aramid paper according to the first invention.
A third invention of the present application provides a conductive aramid paper according to the first or second invention, wherein the aramid constituting the aramid short fiber and the aramid fibrid is polymetaphenylene isophthalamide. It is.
A fourth invention of the present application provides a conductive aramid paper according to any one of the first to third inventions, wherein the conductive filler is carbon fiber.
The fifth invention of the present application is a mixture of aramid short fibers, aramid fibrids and conductive fillers in water, sheeted by a wet papermaking method, and hot-pressed the obtained sheet between a pair of metal rolls, A method for producing a conductive aramid paper according to any one of the first to fourth inventions including plating is provided.
Hereinafter, the present invention will be described in detail.
（アラミド）
　本発明においてアラミドとは、アミド結合の６０％以上が芳香環に直接結合した線状高分子化合物を意味する。このようなアラミドとしては、例えば、ポリメタフェニレンイソフタルアミドおよびその共重合体、ポリパラフェニレンテレフタルアミドおよびその共重合体、コポリパラフェニレン・３，４’－ジフェニルエーテルテレフタルアミドなどが挙げられる。これらのアラミドは、例えば、芳香族酸二塩化物および芳香族ジアミンとの縮合反応による溶液重合法、二段階界面重合法等により工業的に製造されており、市販品として入手することができるが、これに限定されるものではない。これらのアラミドの中では、ポリメタフェニレンイソフタルアミドが良好な成型加工性、難燃性、耐熱性などの特性を備えている点で好ましく用いられる。 (Aramid)
In the present invention, aramid means a linear polymer compound in which 60% or more of amide bonds are directly bonded to an aromatic ring. Examples of such aramids include polymetaphenylene isophthalamide and copolymers thereof, polyparaphenylene terephthalamide and copolymers thereof, and copolyparaphenylene 3,4'-diphenyl ether terephthalamide. These aramids are industrially produced by, for example, a solution polymerization method by a condensation reaction with an aromatic acid dichloride and an aromatic diamine, a two-step interfacial polymerization method, etc., and can be obtained as a commercial product. However, the present invention is not limited to this. Among these aramids, polymetaphenylene isophthalamide is preferably used because it has good molding processability, flame retardancy, heat resistance and the like.
（アラミド短繊維）
　本発明で用いるアラミド短繊維としては、アラミドを原料とする繊維を所定の長さに切断したものが挙げられ、そのような繊維としては、例えば、帝人（株）の「テイジンコーネックス（登録商標）」、「テクノーラ（登録商標）」、デュポン社の「ノーメックス（登録商標）」、「ケブラー（登録商標）」、テイジンアラミド社の「トワロン（登録商標）」等の商品名で入手することができるものが挙げられるが、これらに限定されるものではない。
　アラミド短繊維は、好ましくは、０．０５ｄｔｅｘ以上２５ｄｔｅｘ未満の範囲内の繊度を有することができる。繊度が０．０５ｄｔｅｘ未満の繊維は、湿式法での製造（後述）において凝集を招きやすいために好ましくなく、また、繊度が２５ｄｔｅｘ以上の繊維は、繊維直径が大きくなり過ぎるため、例えば、真円形状で密度を１．４ｇ／ｃｍ3とすると、直径４５μｍ以上である場合、アスペクト比の低下、力学的補強効果の低減、アラミド紙の均一性不良などの不都合が生じる可能性がある。導電性アラミド紙の均一性不良が生じた場合、導電性アラミド紙の導電性にバラツキが生じ、それにより求められる電磁波シールド機能が十分に発現できない可能性があるため好ましくない。アラミド短繊維の長さは、１ｍｍ以上２５ｍｍ未満の範囲から選ぶことができる。短繊維の長さが１ｍｍよりも小さいと、導電性アラミド紙の力学特性が低下し、他方、２５ｍｍ以上のものは、後述する湿式法での導電性アラミド紙の製造に際して「からみ」「結束」などが発生しやすく欠陥の原因となりやすいため好ましくない。 (Aramid short fiber)
Examples of the aramid short fiber used in the present invention include those obtained by cutting a fiber made of aramid into a predetermined length, and examples of such a fiber include “Teijin Conex (registered trademark)” by Teijin Limited. ) "," Technora (registered trademark) ", DuPont" Nomex (registered trademark) "," Kevlar (registered trademark) ", Teijin Aramid" Twaron (registered trademark) " Although what can be mentioned is mentioned, it is not limited to these.
The aramid short fibers can preferably have a fineness within a range of 0.05 dtex or more and less than 25 dtex. A fiber having a fineness of less than 0.05 dtex is not preferable because it tends to cause aggregation in the production by a wet method (described later), and a fiber having a fineness of 25 dtex or more is too large in diameter. If the density is 1.4 g / cm 3 in the shape, when the diameter is 45 μm or more, there may be inconveniences such as a decrease in aspect ratio, a reduction in mechanical reinforcement effect, and aramid paper uniformity failure. When the uniformity defect of the conductive aramid paper occurs, there is a possibility that the conductivity of the conductive aramid paper varies and the required electromagnetic shielding function may not be sufficiently exhibited. The length of the aramid short fiber can be selected from a range of 1 mm or more and less than 25 mm. When the length of the short fiber is smaller than 1 mm, the mechanical properties of the conductive aramid paper are deteriorated. On the other hand, those having a length of 25 mm or more are “entangled” and “bound” when the conductive aramid paper is manufactured by the wet method described later. This is not preferable because it tends to cause defects.
（アラミドファイブリッド）
　本発明で用いるアラミドファイブリッドとは、アラミドからなるフィルム状微小粒子で、アラミドパルプと称することもある。製造方法は、例えば特公昭３５－１１８５１号、特公昭３７－５７３２号公報等に記載の方法が例示される。アラミドファイブリッドは、通常の木材（セルロース）パルプと同じように抄紙性を有するため、水中分散した後、抄紙機にてシート状に成形することができる。この場合、抄紙に適した品質を保つ目的でいわゆる叩解処理を施すことができる。この叩解処理は、ディスクリファイナー、ビーター、その他の機械的切断作用を及ぼす抄紙原料処理機器によって実施することができる。この操作において、ファイブリッドの形態変化は、ＪＩＳ　Ｐ８１２１に規定の濾水度（フリーネス）でモニターすることができる。本発明において、叩解処理を施した後のアラミドファイブリッドの濾水度は、１０～３００ｃｍ3（カナディアンスタンダードフリーネス）の範囲内にあることが好ましい。この範囲より大きな濾水度のファイブリッドでは、それから成形されるシートの強度が低下する可能性がある。他方、１０ｃｍ3よりも小さな濾水度を得ようとすると、投入する機械動力の利用効率が小さくなり、また、単位時間当たりの処理量が少なくなることが多く、さらに、ファイブリッドの微細化が進行しすぎるため、いわゆるバインダー機能の低下を招きやすい。したがって、１０ｃｍ3よりも小さな濾水度を得ようとしても、格段の利点が認められない。 (Aramid Five Brid)
The aramid fibrid used in the present invention is a film-like fine particle made of aramid and may be called aramid pulp. Examples of the production method include those described in JP-B-35-11851, JP-B-37-5732, and the like. Since aramid fibrids have paper-making properties like ordinary wood (cellulose) pulp, it can be formed into a sheet by a paper machine after being dispersed in water. In this case, a so-called beating process can be performed for the purpose of maintaining quality suitable for papermaking. This beating process can be performed by a disk refiner, a beater, or other papermaking raw material processing equipment that exerts a mechanical cutting action. In this operation, the shape change of the fibrid can be monitored with the freeness as defined in JIS P8121. In the present invention, the freeness of the aramid fibrid after the beating treatment is preferably in the range of 10 to 300 cm 3 (Canadian Standard Freeness). For fibrids with a freeness greater than this range, the strength of the sheet formed therefrom may be reduced. On the other hand, if it is desired to obtain a freeness smaller than 10 cm 3 , the utilization efficiency of the mechanical power to be input becomes small, the processing amount per unit time is often reduced, and further refinement of the fibrid is reduced. Since it proceeds too much, the so-called binder function is likely to deteriorate. Therefore, no particular advantage is recognized even when trying to obtain a freeness smaller than 10 cm 3 .
（導電性フィラー）
　本発明で用いる導電性フィラーとしては、約１０-1Ω・ｃｍ以下の体積抵抗を持つ導体から、約１０-1～１０8Ω・ｃｍの体積抵抗を持つ半導体まで、広範囲にわたる導電性を有する繊維状または微粒子（粉末またはフレーク）状物があげられる。このような導電性フィラーとしては、例えば金属繊維、炭素繊維、カーボンブラックなどの均質な導電性を有する材料、あるいは金属めっき繊維、金属粉末混合繊維、カーボンブラック混合繊維など、導電材料と非導電材料とが混合されて全体として導電性を示す材料などが挙げられるが、これらに限定されるものではない。この中で、本発明においては炭素繊維を使用することが好ましい。本発明で用いる炭素繊維は、繊維状有機物を不活性雰囲気にて高温焼成して炭化したものが好ましい。一般に炭素繊維は、ポリアクリロニトリル（ＰＡＮ）繊維を焼成したものと、ピッチを紡糸した後に焼成したものに大別されるが、これ以外にもレーヨンやフェノールなどの樹脂を紡糸後、焼成して製造するものもあり、これらも本発明において使用することができる。焼成に先立ち酸素等を使用して酸化架橋処理を行い、焼成時の融断を防止することも可能である。本発明で用いる炭素繊維の繊度は、０．５～１０ｄｔｅｘの範囲が好ましい。また、繊維長は１ｍｍ～２０ｍｍの範囲から選ばれる。
　導電性フィラーの選択においては、導電性が高く、かつ、後述の湿式抄造法において良好な分散を示す材料を使用することがより好ましい。また、炭素繊維を選択する場合には、更に高強度、かつ脆化しにくいものを選択することが好ましい。そのような材料を選択することにより、本発明の特徴である、電磁波シールド材料に適した導電性、及び熱圧加工により特定の範囲に緻密化された導電性アラミド紙を得ることが可能となる。 (Conductive filler)
The conductive filler used in the present invention has a wide range of conductivity from a conductor having a volume resistance of about 10 −1 Ω · cm or less to a semiconductor having a volume resistance of about 10 −1 to 10 8 Ω · cm. Examples thereof include fibrous or fine particles (powder or flakes). Examples of such conductive fillers include materials having uniform conductivity such as metal fibers, carbon fibers, and carbon black, or conductive materials and non-conductive materials such as metal plating fibers, metal powder mixed fibers, and carbon black mixed fibers. However, the present invention is not limited to these materials. Of these, carbon fibers are preferably used in the present invention. The carbon fiber used in the present invention is preferably carbon fiber obtained by firing a fibrous organic material at a high temperature in an inert atmosphere. In general, carbon fibers are broadly divided into those obtained by firing polyacrylonitrile (PAN) fibers and those obtained by firing pitch after spinning. And these can also be used in the present invention. Prior to firing, it is also possible to carry out an oxidative crosslinking treatment using oxygen or the like to prevent fusing during firing. The fineness of the carbon fiber used in the present invention is preferably in the range of 0.5 to 10 dtex. The fiber length is selected from the range of 1 mm to 20 mm.
In selecting the conductive filler, it is more preferable to use a material having high conductivity and exhibiting good dispersion in the wet papermaking method described later. Moreover, when selecting a carbon fiber, it is preferable to select a carbon fiber having higher strength and less embrittlement. By selecting such a material, it is possible to obtain a conductive aramid paper which is a feature of the present invention, suitable for electromagnetic shielding material, and densified to a specific range by hot pressing. .
（導電性アラミド紙）
　本発明の導電性アラミド紙は、前述のアラミド短繊維、アラミドファイブリッド及び導電性フィラーを含むアラミド紙の表面に金属層を有することを特徴とする。本発明の導電性アラミド紙の金属層形成前の全重量中に占めるアラミド短繊維の含量は、好ましくは５～６０重量％、より好ましくは１０～５５重量％、さらに好ましくは２０～５０重量％であるが、これに限定されるものではない。一般に、アラミド短繊維の含量が５重量％未満の場合は導電性アラミド紙の機械的強度が低下しやすく、６０重量％を超える場合はアラミドファイブリッドの含量が低下し、やはり機械的強度が低下しやすい。本発明の導電性アラミド紙の金属層形成前の全重量中に占めるアラミドファイブリッドの含量は、好ましくは３０～８０重量％、より好ましくは３５～７０重量％、さらに好ましくは４０～６５重量％であるが、これに限定されるものではない。一般に、アラミドファイブリッドの含量が３０重量％未満の場合は導電性アラミド紙の機械的強度が低下しやすく、８０重量％を超える場合は、湿式法での製造（後述）において濾水性が低下し、導電性アラミド紙の均一性不良などを生じやすい。また、本発明の導電性アラミド紙の金属層形成前の全重量中に占める導電性フィラーの含量は、好ましくは１～３０重量％、より好ましくは３～３０重量％である。導電性フィラーの含量が１重量％未満の場合には、所望の導電性を得ることが難しく、また一般に、３０重量％を超える場合は、導電性アラミド紙の機械的強度が低下しやすく、かつ、複雑な方法を用いずに均質な紙を製造することが困難となる。また、アラミド紙はフィブリル化したアラミドを含んでもよい。 (Conductive aramid paper)
The conductive aramid paper of the present invention is characterized by having a metal layer on the surface of the aramid paper containing the aramid short fiber, the aramid fibrid and the conductive filler. The content of short aramid fibers in the total weight of the conductive aramid paper of the present invention before forming the metal layer is preferably 5 to 60% by weight, more preferably 10 to 55% by weight, and still more preferably 20 to 50% by weight. However, the present invention is not limited to this. In general, when the content of aramid short fibers is less than 5% by weight, the mechanical strength of the conductive aramid paper tends to decrease, and when it exceeds 60% by weight, the content of aramid fibrids decreases and the mechanical strength also decreases. It's easy to do. The content of the aramid fibrid in the total weight of the conductive aramid paper of the present invention before forming the metal layer is preferably 30 to 80% by weight, more preferably 35 to 70% by weight, still more preferably 40 to 65% by weight. However, the present invention is not limited to this. In general, when the content of aramid fibrid is less than 30% by weight, the mechanical strength of the conductive aramid paper tends to decrease, and when it exceeds 80% by weight, the drainage decreases in the production by a wet method (described later). It tends to cause poor uniformity of conductive aramid paper. Further, the content of the conductive filler in the total weight of the conductive aramid paper of the present invention before forming the metal layer is preferably 1 to 30% by weight, more preferably 3 to 30% by weight. When the content of the conductive filler is less than 1% by weight, it is difficult to obtain the desired conductivity. In general, when the content exceeds 30% by weight, the mechanical strength of the conductive aramid paper tends to decrease, and Therefore, it is difficult to produce a homogeneous paper without using a complicated method. The aramid paper may also contain fibrillated aramid.
　また、金属層形成に用いられる金属材料としては、金、銀、銅、亜鉛、ニッケル、及びそれらの合金といったものが挙げられる。導電性及び製造コストを考慮すると銅、ニッケルが好ましいが、電磁波シールド性や耐久性を考慮して選択すればよく、特に限定されない。本発明の導電性アラミド紙の表面に形成される金属層の含量については平均値で１０～２０g/m2の範囲内であることが好ましい。金属層の量がこの範囲より小さいと十分な導電性が得られない恐れがある。逆に金属層の量がこの範囲より大きいとコストアップを招く恐れがある。
　本発明の導電性アラミド紙において、前記金属層が適切に形成されているか否かについては、例えば抵抗値計を用いて測定されるアラミド紙の厚み方向の抵抗値により確認される。具体的には、抵抗値計測定で得られる実効抵抗値に、電極との接触面積を乗じた値を厚み方向の抵抗値とし、これが０．０１～０．１０Ω・ｃｍ2の範囲内の値をとる場合に、「表面および内部に連続した金属層が適切に形成され」ていると言える。厚み方向の抵抗値が０．０１Ω・ｃｍ2～０．１０Ω・ｃｍ2の範囲内であれば、軽量でかつ、充分な電磁波シールド特性も有する導電性アラミド紙が提供される。厚み方向の抵抗値が０．０１Ω・ｃｍ2未満では、機器の軽量化が達成されず、０．１０Ω・ｃｍ2を超えると電磁波シールド特性が充分でない。厚み方向の抵抗値は、好ましくは０．０１Ω・ｃｍ2～０．０７Ω・ｃｍ2、より好ましくは０．０１Ω・ｃｍ2～０．０４Ω・ｃｍ2である。
　また、導電性アラミド紙の厚みについては特に制限はないが、一般に、２０μｍ～１００μｍの範囲内の厚さを有していることが好ましく、より好ましくは２５～８０μｍである。２０μｍよりも厚みが小さい場合、機械的特性が低下し、製造工程での搬送等の取り扱い性に問題を生じやすい。他方、１００μｍを超える場合、例えば、電気装置あるいは導体へ据え付ける際に、省スペース化の障害となりやすい。尚、導電性アラミド紙の坪量は、１０～１１０ｇ/ｍ2であるのが好ましい。 Examples of the metal material used for forming the metal layer include gold, silver, copper, zinc, nickel, and alloys thereof. Copper and nickel are preferable in consideration of conductivity and manufacturing cost, but may be selected in consideration of electromagnetic shielding properties and durability, and are not particularly limited. The content of the metal layer formed on the surface of the conductive aramid paper of the present invention is preferably in the range of 10 to 20 g / m 2 on average. If the amount of the metal layer is smaller than this range, sufficient conductivity may not be obtained. Conversely, if the amount of the metal layer is larger than this range, the cost may increase.
In the conductive aramid paper of the present invention, whether or not the metal layer is appropriately formed is confirmed by, for example, the resistance value in the thickness direction of the aramid paper measured using a resistance meter. Specifically, a value obtained by multiplying the effective resistance value obtained by the resistance meter measurement by the contact area with the electrode is used as a resistance value in the thickness direction, and the value is within a range of 0.01 to 0.10 Ω · cm 2. It can be said that “a continuous metal layer is appropriately formed on the surface and inside”. If the resistance value in the thickness direction is in the range of 0.01 Ω · cm 2 to 0.10 Ω · cm 2 , a conductive aramid paper that is lightweight and has sufficient electromagnetic shielding properties is provided. If the resistance value in the thickness direction is less than 0.01 Ω · cm 2 , the weight of the device cannot be reduced, and if it exceeds 0.10 Ω · cm 2 , the electromagnetic shielding characteristics are not sufficient. The resistance value in the thickness direction is preferably 0.01 Ω · cm 2 to 0.07 Ω · cm 2 , more preferably 0.01 Ω · cm 2 to 0.04 Ω · cm 2 .
The thickness of the conductive aramid paper is not particularly limited, but in general, it preferably has a thickness in the range of 20 μm to 100 μm, more preferably 25 to 80 μm. When the thickness is smaller than 20 μm, the mechanical properties are deteriorated, and a problem is easily caused in handling properties such as conveyance in the manufacturing process. On the other hand, when it exceeds 100 μm, for example, when installed on an electric device or conductor, it tends to be an obstacle to saving space. The basis weight of the conductive aramid paper is preferably 10 to 110 g / m 2 .
（導電性アラミド紙の製造）
　以上に述べた本発明の導電性アラミド紙は、一般に、前述したアラミド短繊維、アラミドファイブリッド及び導電性フィラーを混合した後シート化し、一対の金属製ロール間にて熱圧加工した後でめっき加工する方法により製造することができる。
　具体的には、例えば、（ｉ）アラミド短繊維、アラミドファイブリッド及び導電性フィラーを乾式でブレンドした後に、気流を利用してシートを形成し、一対の金属製ロール間にて熱圧加工した後で金属層を形成する方法、（ii）アラミド短繊維、アラミドファイブリッド及び導電性フィラーを液体媒体中で分散混合した後、液体透過性の支持体、例えば網またはベルト上に吐出してシート化し、液体を除いて乾燥し、一対の金属製ロール間にて熱圧加工した後で金属層を形成する方法などを適用することができる。これらの中でも水を媒体として使用する、いわゆる湿式抄造法でシート化し、一対の金属製ロール間にて熱圧加工した後で金属層を形成する方法が好ましく選択される。 (Manufacture of conductive aramid paper)
The conductive aramid paper of the present invention described above is generally plated after the above-mentioned aramid short fibers, aramid fibrids and conductive filler are mixed and then sheeted, and hot pressed between a pair of metal rolls. It can be manufactured by a processing method.
Specifically, for example, (i) after aramid short fibers, aramid fibrids and conductive fillers are dry blended, a sheet is formed using an air stream and hot pressed between a pair of metal rolls. (Ii) Aramid short fibers, aramid fibrids and conductive fillers are dispersed and mixed in a liquid medium, and then discharged onto a liquid-permeable support, such as a net or a belt. For example, a method of forming a metal layer after the liquid is removed and dried and hot-pressed between a pair of metal rolls can be applied. Among these, a method of forming a metal layer after forming into a sheet by a so-called wet papermaking method using water as a medium and hot pressing between a pair of metal rolls is preferably selected.
　湿式抄造法では、少なくともアラミド短繊維、アラミドファイブリッド、及び導電性フィラーの単一または混合物の水性スラリーを抄紙機に送液し分散した後、脱水、搾水および乾燥操作を行うことによって、シートとして巻き取る方法が一般的である。抄紙機としては、例えば、長網抄紙機、円網抄紙機、傾斜型抄紙機及びこれらを組み合わせたコンビネーション抄紙機などを利用することができる。コンビネーション抄紙機での製造の場合、配合比率の異なる水性スラリーをシート成形し合一することにより、複数の紙層からなる複合シートを得ることも可能である。湿式抄造の際に必要に応じて分散性向上剤、消泡剤、紙力増強剤などの添加剤を使用することは差し支えなく、また導電性フィラーが粒子状物である場合には、アクリル系樹脂、定着剤、高分子凝集剤などを添加してもかまわないが、本発明の目的を阻害することがないよう、その使用には注意を払う必要がある。また、本発明の導電性アラミド紙には、本発明の目的を阻害しない範囲で、上記成分以外に、その他の繊維状成分、例えば、ポリフェニレンサルファイド繊維、ポリエーテルエーテルケトン繊維、セルロース系繊維、ポリビニルアルコール繊維、ポリエステル繊維、ポリアリレート繊維、液晶ポリエステル繊維、ポリイミド繊維、ポリアミドイミド繊維、ポリパラフェニレンベンゾビスオキサゾール繊維などの有機繊維、ガラス繊維、ロックウール、ボロン繊維などの無機繊維を添加することもできる。尚、上記添加剤や他の繊維状成分を用いる場合には、導電性アラミド紙の金属層形成前の全重量の２０重量％以下とするのが好ましい。 In the wet papermaking method, at least a single or mixture aqueous slurry of aramid short fibers, aramid fibrids, and conductive fillers is fed to a paper machine and dispersed, followed by dehydration, squeezing and drying operations. As a general rule, a winding method is used. As the paper machine, for example, a long paper machine, a circular paper machine, an inclined paper machine, a combination paper machine combining these, and the like can be used. In the case of production with a combination paper machine, it is also possible to obtain a composite sheet composed of a plurality of paper layers by forming and uniting aqueous slurries having different blending ratios. Additives such as dispersibility improvers, antifoaming agents, and paper strength enhancers can be used as necessary during wet papermaking, and if the conductive filler is in the form of particles, acrylic A resin, a fixing agent, a polymer flocculant, and the like may be added, but care must be taken in the use so as not to hinder the purpose of the present invention. In addition, the conductive aramid paper of the present invention includes other fibrous components, such as polyphenylene sulfide fiber, polyether ether ketone fiber, cellulosic fiber, polyvinyl, in addition to the above components, within the range not impairing the object of the present invention. Addition of organic fibers such as alcohol fiber, polyester fiber, polyarylate fiber, liquid crystal polyester fiber, polyimide fiber, polyamideimide fiber, polyparaphenylene benzobisoxazole fiber, inorganic fiber such as glass fiber, rock wool, boron fiber it can. In addition, when using the said additive and another fibrous component, it is preferable to set it as 20 weight% or less of the total weight before metal layer formation of electroconductive aramid paper.
　このようにして得られるシートは、例えば、一対の平板間または金属製ロール間にて高温高圧で熱圧加工することにより、機械的強度を向上させることができる。熱圧加工の条件は、例えば、金属製ロールを使用する場合、温度１００～４００℃、線圧５０～１０００ｋｇ／ｃｍの範囲内を例示することができるが、本発明の導電性アラミド紙の特徴である高いシールド特性を得るために、ロール温度は３３０℃以上とすることが好ましく、より好ましくは３３０℃～３８０℃である。又、線圧は５０～５００ｋｇ／ｃｍであるのが好ましい。該温度はメタ型アラミドのガラス転移温度より高く、またメタ型アラミドの結晶化温度に近いことから、該温度で熱圧加工することにより機械的強度が向上するだけでなく、導電性アラミド紙を構成する材料同士を強固に密着させることで、厚み方向の抵抗を低減できる。上記の熱圧加工は複数回行ってもよく、また用途によっては過度に省スペース化を必要とせず、１００μｍを超える厚みを必要とする場合も出てくる可能性もあるため、その場合には、上述の方法により得たシート状物を複数枚重ね合わせて熱圧加工を行ってもよい。
　このようにして得られたシートの表面に、金属層を形成する方法としては、真空蒸着法、スパッタリング法および無電解めっき法等が挙げられるが、形成される金属層の均一性、生産性の観点から、無電解めっき法が特に好ましい。
　また、金属の量を増加させるために、金属層を形成する前に表面処理を実施することが可能である。ここで表面処理としては、ＵＶ照射表面処理、プラズマ表面処理、コロナ表面処理、電子線照射表面処理、イオン線照射表面処理、樹脂加工、液体浸漬による表面処理などが挙げられるが、これらに限定されるものではない。表面処理を実施することにより、金属層形成前のシートの表面の表面エネルギーが向上し、金属との界面エネルギーが低下する結果、金属層形成性が向上する。処理の簡便さから、特にＵＶ照射表面処理、プラズマ表面、電子線照射表面処理が好ましい。
　本発明の導電性アラミド紙は、（１）導電性を有していること、（２）耐熱性、難燃性を備えていること、（３）形状安定性が高いこと、（４）良好な加工性を有していることなどの優れた特性を有しており、電気電子機器、特にハイブリッドカー、電気自動車中の電子機器などの電磁波シールド材料として好適に用いることができる。
　以下、本発明を、実施例を挙げてさらに具体的に説明する。なお、これらの実施例は、単なる例示であり、本発明の内容を何ら限定するためのものではない。 Thus, the sheet | seat obtained in this way can improve mechanical strength by carrying out a hot-pressure process at high temperature and high pressure between a pair of flat plates or between metal rolls, for example. The conditions of the hot pressing process can be exemplified, for example, within the range of a temperature of 100 to 400 ° C. and a linear pressure of 50 to 1000 kg / cm when a metal roll is used. The characteristics of the conductive aramid paper of the present invention In order to obtain a high shielding characteristic, the roll temperature is preferably 330 ° C. or higher, more preferably 330 ° C. to 380 ° C. The linear pressure is preferably 50 to 500 kg / cm. Since the temperature is higher than the glass transition temperature of the meta-type aramid and close to the crystallization temperature of the meta-type aramid, not only the mechanical strength is improved by hot pressing at the temperature, but also the conductive aramid paper is used. By firmly adhering the constituent materials, resistance in the thickness direction can be reduced. The above-mentioned hot pressing may be performed a plurality of times, and depending on the application, it does not require excessive space saving and may require a thickness exceeding 100 μm. A plurality of sheet-like materials obtained by the above-described method may be superposed to perform hot pressing.
Examples of a method for forming a metal layer on the surface of the sheet thus obtained include a vacuum deposition method, a sputtering method, an electroless plating method, and the like. From the viewpoint, the electroless plating method is particularly preferable.
Further, in order to increase the amount of metal, it is possible to perform a surface treatment before forming the metal layer. Examples of the surface treatment include UV irradiation surface treatment, plasma surface treatment, corona surface treatment, electron beam irradiation surface treatment, ion beam irradiation surface treatment, resin processing, and surface treatment by liquid immersion. It is not something. By performing the surface treatment, the surface energy of the surface of the sheet before forming the metal layer is improved, and the interface energy with the metal is lowered, so that the metal layer formability is improved. In view of simplicity of treatment, UV irradiation surface treatment, plasma surface, and electron beam irradiation surface treatment are particularly preferable.
The conductive aramid paper of the present invention has (1) conductivity, (2) heat resistance and flame resistance, (3) high shape stability, and (4) good. It has excellent characteristics such as having excellent processability, and can be suitably used as an electromagnetic shielding material for electric and electronic devices, particularly electronic devices in hybrid cars and electric vehicles.
Hereinafter, the present invention will be described more specifically with reference to examples. These examples are merely illustrative and are not intended to limit the content of the present invention.
（測定方法）
（１）シートの目付、厚み、密度
　ＪＩＳ　Ｃ　２３００－２に準じて実施し、密度は（目付／厚み）により算出した。
（２）引張強度
　幅１５ｍｍ、チャック間隔５０ｍｍ、引張速度５０ｍｍ／ｍｉｎで実施した。
（３）表面抵抗率
　ロレスターＭＣＰ－Ｔ３５０　ＥＳＰタイプ（三菱化学製）を用いて測定した。
（４）厚み方向抵抗値
　一対の電極で挟み、シートにかかる面圧（電極の重量も含む）が２５０ｇ／ｃｍ2の状態で、ミリオームハイテスタ（日置電気製）を用いて測定した抵抗値に電極の面積を乗じた。
（５）形状安定性
　ＪＩＳ　Ｌ　１０９６　Ａ法（４５°カンチレバー法）に準じて測定した。長いほど、形状安定性が優れていると言える。
（６）耐熱性
　表１～３に示した温度で１時間保持した後、引張強度を測定した。
（７）電磁波シールド性能
　ＫＥＣ法（社団法人関西電子工業振興センターの標準測定方法であるＭＩＬ－ＳＴＤ２８５）に基づいて測定した。具体的には、近距離間に発信アンテナと受信アンテナが設置されたシールドボックス内の所定の位置（アンテナ間）にサンプルシートを保持し、周波数を１０Ｍ～１ＧＨｚの範囲で変化させて発信し、その時の各周波数における電界の減衰状態をスペクトラム・アナライザーで測定した。近接界における電磁波シールド性が評価できる。 (Measuring method)
(1) Sheet weight, thickness and density of sheet The measurement was performed according to JIS C 2300-2, and the density was calculated by (weight / thickness).
(2) Tensile strength The test was carried out at a width of 15 mm, a chuck interval of 50 mm, and a tensile speed of 50 mm / min.
(3) Surface resistivity Measured using a Lorester MCP-T350 ESP type (Mitsubishi Chemical).
(4) Thickness direction resistance value The resistance value measured using a milliohm high tester (manufactured by Hioki Electric) in a state where the surface pressure (including the weight of the electrode) applied to the sheet is 250 g / cm 2 between the pair of electrodes. Multiplyed by electrode area.
(5) Shape stability It was measured according to JIS L 1096 A method (45 ° cantilever method). It can be said that the longer the shape, the better the shape stability.
(6) Heat resistance After holding at the temperatures shown in Tables 1 to 3 for 1 hour, the tensile strength was measured.
(7) Electromagnetic Shielding Performance Measured based on the KEC method (MIL-STD285, which is a standard measurement method of Kansai Electronics Industry Promotion Center). Specifically, the sample sheet is held at a predetermined position (between the antennas) in the shield box where the transmitting antenna and the receiving antenna are installed in a short distance, and the frequency is changed in the range of 10 M to 1 GHz, and then transmitted. The attenuation state of the electric field at each frequency at that time was measured with a spectrum analyzer. The electromagnetic shielding property in the near field can be evaluated.
（原料調製）
　特開昭５２－１５６２１号公報に記載の、ステーターとローターの組み合わせで構成されるパルプ粒子の製造装置（湿式沈殿機）を用いて、ポリメタフェニレンイソフタルアミドのファイブリッドを製造した。これを叩解機で処理し長さ加重平均繊維長を０．９ｍｍに調節した（濾水度２００ｃｍ3）。一方、デュポン社製メタアラミド繊維（ノーメックス（登録商標）、単糸繊度２．２ｄｔｅｘ）を長さ６ｍｍに切断（以下「アラミド短繊維」と記載）し抄紙用原料とした。 (Raw material preparation)
A polymetaphenylene isophthalamide fibrid was manufactured using a pulp particle manufacturing apparatus (wet precipitator) composed of a combination of a stator and a rotor described in JP-A-52-15621. This was treated with a beating machine, and the length weighted average fiber length was adjusted to 0.9 mm (freeness 200 cm 3 ). On the other hand, a meta-aramid fiber (Nomex (registered trademark), single yarn fineness 2.2 dtex) manufactured by DuPont was cut into a length of 6 mm (hereinafter referred to as “aramid short fiber”) to obtain a papermaking raw material.
（実施例１～３）
　上記のとおり調製したメタアラミドファイブリッド、メタアラミド短繊維、及び炭素繊維（東邦テナックス株式会社製、繊維長３ｍｍ、単繊維径７μｍ、繊度０．６７ｄｔｅｘ、体積抵抗率１．６×１０-3Ω・ｃｍ）をそれぞれ水中に分散してスラリーを作製した。このスラリーを、メタアラミドファイブリッド、メタアラミド短繊維、及び炭素繊維が、表１に示す配合比率となるように混合し、タッピー式手抄き機（断面積３２５ｃｍ2）で処理してシート状物を作製した。次いで、得られたシートを１対の金属製カレンダーロールにより温度３３０℃、線圧１５０ｋｇ／ｃｍで熱圧加工したシートの表面に、無電解めっき法により金属（銅－ニッケル合金）層を形成し、導電性アラミド紙を得た。このようにして得られた導電性アラミド紙の主要特性値を表１に示す。
（実施例４）
　実施例１と同様の方法にて得られたシート状物を１対の金属製カレンダーロールにより温度３５０℃、線圧１５０ｋｇ／ｃｍで熱圧加工したシートの表面に、無電解めっき法により金属（銅－ニッケル合金）層を形成し、導電性アラミド紙を得た。このようにして得られた導電性アラミド紙の主要特性値を表１に示す。 (Examples 1 to 3)
Meta-aramid fibrids, meta-aramid short fibers and carbon fibers prepared as described above (manufactured by Toho Tenax Co., Ltd., fiber length 3 mm, single fiber diameter 7 μm, fineness 0.67 dtex, volume resistivity 1.6 × 10 −3 Ω · cm) were dispersed in water to prepare slurry. This slurry was mixed so that meta-aramid fibrids, meta-aramid short fibers, and carbon fibers would have the blending ratios shown in Table 1, and processed with a tappy hand machine (cross-sectional area of 325 cm 2 ) to form a sheet. Was made. Next, a metal (copper-nickel alloy) layer was formed by electroless plating on the surface of the sheet obtained by hot-pressing the obtained sheet with a pair of metal calender rolls at a temperature of 330 ° C. and a linear pressure of 150 kg / cm. A conductive aramid paper was obtained. Table 1 shows main characteristic values of the conductive aramid paper thus obtained.
Example 4
A sheet (obtained by the same method as in Example 1) was hot-pressed at a temperature of 350 ° C. and a linear pressure of 150 kg / cm with a pair of metal calender rolls, and a metal ( A copper-nickel alloy) layer was formed to obtain conductive aramid paper. Table 1 shows main characteristic values of the conductive aramid paper thus obtained.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
（比較例１及び２）
　上記のとおり調製したメタアラミドファイブリッド、メタアラミド短繊維、及び炭素繊維（東邦テナックス株式会社製、繊維長３ｍｍ、単繊維径７μｍ、繊度０．６７ｄｔｅｘ、体積抵抗率１．６×１０-3Ω・ｃｍ）をそれぞれ水中に分散してスラリーを作製した。このスラリーを、メタアラミドファイブリッド、メタアラミド短繊維、及び炭素繊維が、表２に示す配合比率となるように混合し、タッピー式手抄き機（断面積３２５ｃｍ2）で処理してシート状物を作製した。次いで、得られたシートの表面に、無電解めっき法により金属（銅－ニッケル合金）層を形成し、導電性アラミド紙を得た。このようにして得られた導電性アラミド紙の主要特性値を表２に示す。
（比較例３）
　上記のとおり調製したメタアラミドファイブリッド、メタアラミド短繊維をそれぞれ水中に分散してスラリーを作製した。このスラリーを、メタアラミドファイブリッド、メタアラミド短繊維が、表２に示す配合比率となるように混合し、タッピー式手抄き機（断面積３２５ｃｍ2）で処理してシート状物を作製した。次いで、得られたシートを１対の金属製カレンダーロールにより温度３３０℃、線圧１５０ｋｇ／ｃｍで熱圧加工したシートの表面に、無電解めっき法により金属（銅－ニッケル合金）層を形成し、導電性アラミド紙を得た。このようにして得られた導電性アラミド紙の主要特性値を表２に示す。
（比較例４）
　上記のとおり調製したメタアラミドファイブリッド、メタアラミド短繊維をそれぞれ水中に分散してスラリーを作製した。このスラリーを、メタアラミドファイブリッド、メタアラミド短繊維が、表２に示す配合比率となるように混合し、タッピー式手抄き機（断面積３２５ｃｍ2）で処理してシート状物を作製した。次いで、得られたシートの表面に、従来公知の無電解めっき法により金属（銅－ニッケル合金）層を形成し、導電性アラミド紙を得た。このようにして得られた導電性アラミド紙の主要特性値を表２に示す。 (Comparative Examples 1 and 2)
Meta-aramid fibrids, meta-aramid short fibers and carbon fibers prepared as described above (manufactured by Toho Tenax Co., Ltd., fiber length 3 mm, single fiber diameter 7 μm, fineness 0.67 dtex, volume resistivity 1.6 × 10 −3 Ω · cm) were dispersed in water to prepare slurry. This slurry was mixed so that the meta-aramid fibrids, meta-aramid short fibers, and carbon fibers had the blending ratios shown in Table 2, and processed with a tappy hand machine (cross-sectional area of 325 cm 2 ) to obtain a sheet-like material. Was made. Next, a metal (copper-nickel alloy) layer was formed on the surface of the obtained sheet by electroless plating to obtain conductive aramid paper. Table 2 shows the main characteristic values of the conductive aramid paper thus obtained.
(Comparative Example 3)
The meta-aramid fibrids and meta-aramid short fibers prepared as described above were each dispersed in water to prepare a slurry. The slurry was mixed so that the meta-aramid fibrids and the meta-aramid short fibers had a blending ratio shown in Table 2, and processed with a tappy hand machine (cross-sectional area of 325 cm 2 ) to produce a sheet. Next, a metal (copper-nickel alloy) layer was formed by electroless plating on the surface of the sheet obtained by hot-pressing the obtained sheet with a pair of metal calender rolls at a temperature of 330 ° C. and a linear pressure of 150 kg / cm. A conductive aramid paper was obtained. Table 2 shows the main characteristic values of the conductive aramid paper thus obtained.
(Comparative Example 4)
The meta-aramid fibrids and meta-aramid short fibers prepared as described above were each dispersed in water to prepare a slurry. The slurry was mixed so that the meta-aramid fibrids and the meta-aramid short fibers had a blending ratio shown in Table 2, and processed with a tappy hand machine (cross-sectional area of 325 cm 2 ) to produce a sheet. Next, a metal (copper-nickel alloy) layer was formed on the surface of the obtained sheet by a conventionally known electroless plating method to obtain conductive aramid paper. Table 2 shows the main characteristic values of the conductive aramid paper thus obtained.
Figure JPOXMLDOC01-appb-T000002
 ＊１：比較例３は熱圧加工後のシート
Figure JPOXMLDOC01-appb-T000002
 * 1: Comparative Example 3 is a sheet after hot pressing
（比較例５）
　上記のとおり調製したメタアラミドファイブリッド、メタアラミド短繊維、及び炭素繊維（東邦テナックス株式会社製、繊維長３ｍｍ、単繊維径７μｍ、繊度０．６７ｄｔｅｘ、体積抵抗率１．６×１０-3Ω・ｃｍ）をそれぞれ水中に分散してスラリーを作製した。このスラリーを、メタアラミドファイブリッド、メタアラミド短繊維、及び炭素繊維が、表３に示す配合比率となるように混合し、タッピー式手抄き機（断面積３２５ｃｍ2）で処理してシート状物を作製した。次いで、得られたシートを１対の金属製カレンダーロールにより温度３３０℃、線圧１５０ｋｇ／ｃｍで熱圧加工し、導電性アラミド紙を得た。このようにして得られた導電性アラミド紙の主要特性値を表２に示す。
（比較例６）
　ポリエステル系繊維からなる織物（経糸５６ｄｔｅｘ／３６ｆ、緯糸５６ｄｔｅｘ／３６ｆ）を精練、乾燥、熱処理した後、無電解めっき処方により繊維表面を金属で被覆し、導電性織物を得た。このようにして得られた導電性織物の主要特性値を表３に示す。 (Comparative Example 5)
Meta-aramid fibrids, meta-aramid short fibers and carbon fibers prepared as described above (manufactured by Toho Tenax Co., Ltd., fiber length 3 mm, single fiber diameter 7 μm, fineness 0.67 dtex, volume resistivity 1.6 × 10 −3 Ω · cm) were dispersed in water to prepare slurry. This slurry was mixed so that the meta-aramid fibrids, meta-aramid short fibers, and carbon fibers had the blending ratios shown in Table 3, and processed with a tappy hand machine (cross-sectional area of 325 cm 2 ) to obtain a sheet-like material. Was made. Next, the obtained sheet was hot-pressed with a pair of metal calender rolls at a temperature of 330 ° C. and a linear pressure of 150 kg / cm to obtain conductive aramid paper. Table 2 shows the main characteristic values of the conductive aramid paper thus obtained.
(Comparative Example 6)
A woven fabric made of polyester fibers (warp 56 dtex / 36 f, weft 56 dtex / 36 f) was scoured, dried and heat-treated, and then the surface of the fiber was coated with a metal by electroless plating to obtain a conductive woven fabric. The main characteristic values of the conductive fabric thus obtained are shown in Table 3.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表１に示されるように、本発明品である実施例１～４の導電性アラミド紙は、表面抵抗率、厚み方向の抵抗値、形状安定性、耐熱性について優れた特性を示した。また、実施例１の導電性アラミド紙の電磁波シールド性能を測定したところ、表４に示すように、優れたシールド性能を示した。これに対して、表２に示されるように、比較例１～５の導電性アラミド紙の表面抵抗率、厚み方向の抵抗値はいずれも高い値を示し、目的とする電磁波シールド材料としては不十分であることがわかる。
　また、比較例６については、耐熱が低く、形状安定性も低いことから、ハイブリッドカー、電気自動車など、高周波大電流が流れることによる導線の発熱に耐えうる耐熱性の高い電磁波シールド材料としては不十分であることが示唆された。
　したがって、電気電子機器、特にハイブリッドカー、電気自動車中の電子機器などの電磁波シールド材料として有用な、導電性を持ち、形状安定性、加工性や機械的強度に優れた耐熱性の高い導電性アラミド紙を得るためには、上記実施例で例示した導電性アラミド紙を用いることが有効であることが判明した。 As shown in Table 1, the conductive aramid papers of Examples 1 to 4, which are products of the present invention, exhibited excellent characteristics in terms of surface resistivity, thickness direction resistance, shape stability, and heat resistance. Moreover, when the electromagnetic shielding performance of the conductive aramid paper of Example 1 was measured, as shown in Table 4, it showed excellent shielding performance. On the other hand, as shown in Table 2, the conductive aramid papers of Comparative Examples 1 to 5 both have high surface resistivity and thickness direction resistance, and are not suitable as the intended electromagnetic shielding material. It turns out that it is enough.
Further, Comparative Example 6 has low heat resistance and low shape stability, so it is not suitable as an electromagnetic shielding material with high heat resistance that can withstand the heat generation of a conductor due to high-frequency, high-current flow, such as a hybrid car or an electric vehicle. It was suggested that it was sufficient.
Therefore, it is useful as an electromagnetic shielding material for electric and electronic equipment, especially hybrid cars and electronic equipment in electric cars, etc., and has high conductivity and high heat resistance and conductive aramid having excellent shape stability, workability and mechanical strength. In order to obtain paper, it has been found that it is effective to use the conductive aramid paper exemplified in the above examples.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004

Claims (5)

  1. 　アラミド短繊維、アラミドファイブリッド及び導電性フィラーを含むアラミド紙の表面に金属層を有する、厚み方向の抵抗値が０．０１～０．１０Ω・ｃｍ2である、導電性アラミド紙。 A conductive aramid paper having a metal layer on the surface of an aramid paper containing an aramid short fiber, an aramid fibrid, and a conductive filler, and having a resistance value in the thickness direction of 0.01 to 0.10 Ω · cm 2 .
  2. 　厚みが２０～１００μｍである、請求項１記載の導電性アラミド紙。 2. The conductive aramid paper according to claim 1, wherein the thickness is 20 to 100 μm.
  3. 　アラミド短繊維及びアラミドファイブリッドを構成するアラミドがポリメタフェニレンイソフタルアミドである、請求項１または２記載の導電性アラミド紙。 The conductive aramid paper according to claim 1 or 2, wherein the aramid constituting the aramid short fiber and the aramid fibrid is polymetaphenylene isophthalamide.
  4. 　導電性フィラーが炭素繊維である、請求項１～３のいずれかに記載の導電性アラミド紙。 The conductive aramid paper according to any one of claims 1 to 3, wherein the conductive filler is carbon fiber.
  5. 　アラミド短繊維、アラミドファイブリッド及び導電性フィラーを水中で混合し、
    　湿式抄造法でシート化し、
    　得られたシートを一対の金属製ロール間にて熱圧加工し、
    　熱圧加工したシートをメッキ加工すること
    を含む請求項１から４のいずれかに記載の導電性アラミド紙の製造方法。     Mix aramid short fiber, aramid fibrid and conductive filler in water,
    Sheeted by wet papermaking,
    The obtained sheet is hot-pressed between a pair of metal rolls,
    The method for producing conductive aramid paper according to any one of claims 1 to 4, comprising plating a hot-pressed sheet.
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KR20160048815A (en) 2016-05-04

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