Classifications

• • 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
  • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L75/00—Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
  • C08L75/04—Polyurethanes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/24—Electrically-conducting paints
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/60—Additives non-macromolecular
  • C09D7/61—Additives non-macromolecular inorganic
  • C09D7/62—Additives non-macromolecular inorganic modified by treatment with other compounds
• • 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
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/09—Use of materials for the conductive, e.g. metallic pattern
  • H05K1/092—Dispersed materials, e.g. conductive pastes or inks
  • H05K1/095—Dispersed materials, e.g. conductive pastes or inks for polymer thick films, i.e. having a permanent organic polymeric binder
• • 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
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
  • H05K3/12—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using thick film techniques, e.g. printing techniques to apply the conductive material or similar techniques for applying conductive paste or ink patterns
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/08—Metals
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K9/00—Use of pretreated ingredients
  • C08K9/02—Ingredients treated with inorganic substances
• • 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
  • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
  • H05K2201/02—Fillers; Particles; Fibers; Reinforcement materials
  • H05K2201/0203—Fillers and particles
  • H05K2201/0206—Materials
  • H05K2201/0218—Composite particles, i.e. first metal coated with second metal

Definitions

• This invention relates to an electrically conductive composition containing silver-plated filler particles.
• Silver is utilized as an electrically conductive filler in many commercially available electrically conductive coatings, and encapsulants because its oxide is electrically conductive, and therefore, silver filled systems encounter little or no loss of conductivity during high temperature curing, aging, or other conditions under which the silver may be oxidized.
• a disadvantage of the use of silver is its high cost and the risk of silver migration within the system.
• Copper is another conductive material that may be utilized because it is capable of being processed in forms similar to those in which silver is available, i.e., in powder, dendritic and flake form.
• the main disadvantage of copper is that its oxide is not conductive, and any surface copper oxide formed during drying or curing limits the conductivity of the system even if close interparticle contact is created.
• many other materials that provide electrical conductivity oxidize under the conditions necessary for formation of a conductive coating.
• the present invention provides an electrically conductive composition
• an electrically conductive composition comprising a binder, filler particles, in which at least a portion of the filler particles are silver-plated, and optionally, solvent.
• the sheet resistivity of the composition is lower than 0.100 Ohm/square/25 micron.
• Another embodiment provides electronic devices manufactured using the electrically conductive composition of the invention.
• Still another embodiment is directed to a process of making or forming an electronic device using the electrically conductive composition of the invention.
• the process comprises dispensing, for example, by stencil, screen, rotogravure or flexo printing, the electrically conductive composition of the invention onto a substrate to form conductive tracts or electronic circuitry, and then curing and/or drying the composition to obtain conductivity.
• Exemplary electronic devices that might use these electrically conductive compositions encompass computers and computer equipment, such as printers, fax machines, scanners, keyboards and the like; household appliances; medical sensors; automotive sensors and the like; and personal electronic devices, such as telephones, mobile phones, calculators, remote controls, cameras, CD-players, DVD-players, cassette tape recorders and the like.
• the binder component of the electrically conductive coating or encapsulant will comprise a thermoplastic system, a thermoset system or a mixture of thermoset and thermoplastic systems.
• thermoplastic system of the binder component is either a functional or a non-functional thermoplastic polymer.
• suitable thermoplastic polymers include, but are not limited to, polyurethane elastomers, polyesters, phenolic resins, acrylic polymers, acrylic block copolymers, acrylic polymers having tertiary-alkyl amide functionality, polysiloxane polymers, polystyrene copolymers, polyvinyl polymers, divinylbenzene copolymers, polyetheramides, polyvinyl acetals, polyvinyl butyrals, polyvinyl acetols, polyvinyl alcohols, polyvinyl acetates, polyvinyl chlorides, methylene polyvinyl ethers, cellulose acetates, styrene acrylonitriles, amorphous polyolefins, thermoplastic urethanes, polyacrylonitriles, ethylene vinyl acetate copolymers, ethylene vinyl acetate
• binder that may be utilized is ESTANE 5703P, which is a polyester-type thermoplastic polyurethane available from Noveon, Ohio, USA; PKHC, which is a phenoxy resin available from Inchem, South Carolina, USA; and UCAR VAGH, which is a copolymer of polyvinylalcohol, polyvinylacetate and polyvinylchloride commercially available from the Dow Chemical Company.
• thermoset system of the binder component is either a functional or a non-functional thermoset polymer.
• Suitable thermoset polymers include, but are not limited to, phenolics, urethanes, phenoxy resins, polyesters, epoxies, melamines and mixtures thereof.
• One commercially available binder that may be utilized is Bakelite Hartz 9132KP, which is a phenolic resin commercially available from Bakelite.
• the total binder content is typically in the range of about 2 to about 50 weight percent of the composition and preferably in the range of about 2 to about 40 weight percent of the composition.
• the core of the silver-plated fillers can be electrically conductive or electrically non-conductive.
• a combination of silver-plated fillers, with electrically conductive core and with electrically non-conductive core, may be used.
• Exemplary cores include, but are not limited to, copper, nickel, palladium, carbon black, carbon fiber, graphite, aluminum, indium tin oxide, glass, polymers, antimony doped tin oxide, silica, alumina, fiber, clay, and mixtures thereof.
• the core of the silver-plated filler particle is copper.
• the silver content of the silver-plated filler must be sufficient to provide adequate electrical conductivity and is typically in the range of about 0.2 to about 25 weight percent of the silver-plated filler.
• the one or more silver-plated filler particles comprise in the range of about 1 to about 99 weight percent of the composition and preferably in the range of about 20 to about 70 weight percent of the composition.
• one or more electrically conductive filler materials are utilized in the composition in addition to the silver-plated fillers particles.
• Exemplary conductive filler materials include, but are not limited to, silver, copper, gold, palladium, platinum, nickel, gold or silver-coated nickel, carbon black, carbon fiber, graphite, aluminum, indium tin oxide, silver coated copper, silver coated aluminum, metallic coated glass spheres, metallic coated filler, metallic coated polymers, silver coated fiber, silver coated spheres, antimony doped tin oxide, conductive nanospheres, nano silver, nano aluminum, nano copper, nano nickel, carbon nanotubes and mixtures thereof.
• the electrically conductive filler material may be the same as or different than the core of any silver-plated filler particle utilized in the composition.
• the one or more electrically conductive filler materials comprise in the range of about 0 to about 99 weight percent of the composition and preferably in the range of up to about 40 weight percent of the composition.
• the viscosity of the composition can be adjusted with solvents. It is generally preferred that the composition have a low viscosity to enable efficient dispensing, stencil or screen printing of the composition.
• the composition has a viscosity in the range of about 50 to about 150,000 mPas, and in another embodiment is in the range of about 500 to about 50,000 mPas.
• the lower range of viscosity from about 500 to about 4,000 mPas, is preferred for rotogravure or flexo printing of the composition.
• Higher range of viscosity, from about 3,000 to 50,000 mPas, is preferred for dispensing, stencil or screen printing the composition.
• Exemplary solvents that may be utilized, either separately or in combination, are glycidyl ethers, for example 1,4-butanediol diglycidyl ether; p-tert-butyl-phenyl glycidyl ether, allyl glycidyl ether, glycerol diglycidyl ether, butyldiglycol, 2-(2-butoxyethoxy)-ethylester, butylglycolacetate, acetic acid, 2-butoxyethylester, butylglycol, 2-butoxyethanol, isophorone, 3,3,5 trimethyl-2-cyclohexene-1-one, dimethylsuccinate, dimethylglutarate, dimethyladipate, water, acetic acid, dipropylene glycol (mono)methyl ether, propylacetate, glycidyl ether of alkyl phenol (commercially available from Cardolite Corporation as Cardolite NC513), although other solvents may be utilized
• Additional ingredients may be included in the formulation to provide desired properties.
• Various additives that may be included are surface active agents, surfactants, wetting agents, antioxidants, thixotropes, reinforcement materials, silane functional perfluoroether, phosphate functional perfluoroether, Canes, titanates, wax, phenol formaldehyde, air release agents, flow additives, adhesion promoters, rheology modifiers, surfactants, spacer beads and mixtures thereof.
• the ingredients are specifically chosen to obtain the desired balance of properties for the use of the resins utilized in the particular composition.
• the additional ingredient comprises up to about 20 weight percent of the composition and preferably up to about 10 weight percent of the composition.
• compositions are combined and then applied by dispensing, stencil, screen, rotogravure or flexo printing onto a substrate to form conductive tracts or electronic circuitry, followed by curing and/or drying to produce conductivity.
• the composition is cured and/or dried at 120° C. for about 10 minutes.
• the composition may be cured and/or dried at higher temperatures for less time. In general, these compositions provide sheet resistivity of less than 0.100 Ohm/square/25 ⁇ m.
• a comparative Sample 1 and Samples A-G were prepared by dissolving the binder in a heated solvent (40° C.) with stirring until a homogenous mixture was formed, The samples were cooled to room temperature, filler was added, and the mixture stirred for an additional 30 minutes. As needed, a 3-roll mill (Buhler) was used to mil the compositions. Each composition was applied as a track of 100 ⁇ 2 mm with a thickness of about 5-8 ⁇ m on a polyester sheet. The composition was cured and/or dried at 120° C. for 10 minutes, after which the sheet resistance was measured using a Keithley 2000 Multimeter. Sheet resistivity (SR) was calculated by the formula:
• compositions and sheet resistivity are reported in Table 1: Compositions and Sheet Resistivity.
• Comparative Sample 1 with silver flake filler had a sheet resistivity of 0.010 Ohms/square/25 ⁇ m.
• Samples made with mixtures of silver flakes and silver plated coppers (Samples A-C) had comparable sheet resistivity to the Comparative Sample 1 and acceptable sheet resistivity, lower than 0.100 Ohm/square/25 micron.
• Samples made with only silver plated copper, without any silver flakes also resulted in comparable sheet resistivity values to Comparative Sample 1, and acceptable sheet resistivity, lower than 0.100 Ohm/square/25 micron.
• Samples D-G demonstrated that various binder systems may be used to result in comparable sheet resistivity values as Comparative Sample 1, and acceptable sheet resistivity, lower than 0.100 Ohm/square/25 micron.

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Citations (14)

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• 2007
  • 2007-09-13 PL PL07814826T patent/PL2191482T3/pl unknown
  • 2007-09-13 WO PCT/US2007/078334 patent/WO2009035453A1/en active Application Filing
  • 2007-09-13 EP EP07814826.9A patent/EP2191482B1/en active Active
  • 2007-09-13 KR KR1020107006979A patent/KR101399920B1/ko active IP Right Grant
  • 2007-09-13 CN CN2007801009092A patent/CN101919005A/zh active Pending
  • 2007-09-13 JP JP2010524825A patent/JP5350384B2/ja not_active Expired - Fee Related
• 2008
  • 2008-05-16 TW TW097117991A patent/TWI424448B/zh active
• 2010
  • 2010-03-12 US US12/722,891 patent/US20100209599A1/en not_active Abandoned
• 2015
  • 2015-05-13 US US14/711,003 patent/US10388423B2/en active Active

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