# US 5,344,593 A · Electroconductive elastomer-forming composition > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,344,593 A - Document ID: US5344593A - Status: Granted - Kind: A - Application number: 07/853,813 - Filed: 1992-03-19 - Granted: 1994-09-06 - Earliest claimed: 1991-03-27 - Assignees: Japan Synthetic Rubber Co., Ltd. - Inventors: Hideki Chiba; Hisao Igarashi; Naoshi Yasuda; Yasuo Matsuki - Web page: https://patentgrep.com/patent/US5344593A ## CPC - H01B 1/24: the conductive material comprising carbon-silicon compounds, carbon or silicon - C08L 83/04: Polysiloxanes - H01B 1/22: the conductive material comprising metals or alloys - C08G 77/12: containing silicon bound to hydrogen - C08G 77/20: containing silicon bound to unsaturated aliphatic groups - C08G 77/70: {Siloxanes defined by use of the MDTQ nomenclature} - H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K}) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS ## Abstract An electroconductive elastomer-forming composition comprising (a) 100 parts by weight of a vinyl group-containing polydimethylsiloxane having a standard polystyrene-reduced molecular weight of 10,000-40,000, (b) 5-50 parts by weight of a hydrosilyl group-containing polydimethylsiloxane having a standard polystyrene-reduced molecular weight of 10,000-40,000 and (c) 30-1,000 parts by weight of electroconductive particles. Said composition can form a conductor of small thickness having good conductivity, excellent heat resistance and excellent durability. ## Claims ### Claim 1 An electroconductive elastomer-forming composition consisting of (a) 100 parts by weight of a vinyl group-containing polydimethylsiloxane having a standard polystyrene-reduced molecular weight of 10,000-40,000, and up to 5% by weight based on component (a) of another polysiloxane, (b) 5-50 parts by weight of a hydrosilyl group-containing polydimethylsiloxane having a standard polystyrene-reduced molecular weight of 10,000-40,000, and up to 5% by weight based on component (b) of another hydrosilyl group-containing polysiloxane, (c) 30-1,000 parts by weight of electroconductive particles, an inorganic filler other than the electroconductive particles and a curing catalyst. ### Claim 2 (depends on 1) The composition according to claim 1, wherein the polydimethylsiloxane (a) contains vinyl groups at the two terminals. ### Claim 3 (depends on 1) The composition according to claim 1, wherein the molecular weight distribution index (standard polystyrene-reduced weight-average molecular weight, Mw/standard polystyrene-reduced number-average molecular weight, Mn) of the component (a) is 2.0 or less. ### Claim 4 (depends on 1) The composition according to claim 1, wherein said another polysiloxane is a vinyl group-containing polydimethylsiloxane whose molecular weight is different from that of the component (a), or a vinyl group-containing polydimethylsiloxane whose molecular weight is different from that of the component (a) and whose methyl groups are partially substituted with phenyl groups. ### Claim 5 (depends on 1) The composition according to claim 1, wherein the component (b) has a hydrosilyl equivalent in a range of 350-1,100. ### Claim 6 (depends on 1) The composition according to claim 1, wherein the Mw/Mn of the component (b) is 2.0 or less. ### Claim 7 (depends on 1) The composition according to claim 1, wherein said another hydrosilyl group containing polysiloxane is a hydrosilyl group-containing polydimethylsiloxane whose molecular weight or hydrosiyl equivalent or both of them are different from those of the component (b), or a hydrosilyl group-containing polydimethylsiloxane whose molecular weight is different from that of the component (b) and whose methyl groups of siloxane are partially substituted with phenyl groups. ### Claim 8 (depends on 7) The composition according to claim 7, wherein the proportion of the component (b) to the component (a) is 10-30 parts by weight per 100 parts by weight of the component (a). ### Claim 9 (depends on 1) The composition according to claim 1, wherein the electroconductive particles (c) are particles of at least one metal having electroconductivity. ### Claim 10 (depends on 9) The composition according to claim 9, wherein the metal having electroconductivity is nickel, iron, copper, zinc, chromium, silver, cobalt or aluminum. ### Claim 11 (depends on 9) The composition according to claim 9, wherein the metal having electroconductivity is nickel, iron or copper. ### Claim 12 (depends on 1) The composition according to claim 1, wherein the electroconductive particles (c) are nickel particles whose surfaces are coated with gold. ### Claim 13 (depends on 1) The composition according to claim 1, wherein the electroconductive particles (c) have particle diameters of 3-200 .mu.m. ### Claim 14 (depends on 1) The composition according to claim 1, wherein the proportion of the electroconductive particles (c) is 10-750 parts by weight per 100 parts by weight of the component (a). ### Claim 15 (depends on 1) The composition of claim 1, wherein the inorganic filler is aerogel silica. ### Claim 16 (depends on 1) The composition of claim 1, wherein the curing catalyst is a platinum catalyst obtained by adding tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane to sodium chloroplatinate.