# US 5,352,718 A · Electrorheological semisolid > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,352,718 A - Document ID: US5352718A - Status: Granted - Kind: A - Application number: 07/779,906 - Filed: 1991-10-21 - Granted: 1994-10-04 - Earliest claimed: 1990-10-24 - Assignees: Bridgestone Corporation - Inventors: Yuichi Ishino; Takayuki Maruyama; Tasuku Saito - Web page: https://patentgrep.com/patent/US5352718A ## CPC - C10M 171/001: {Electrorheological fluids; smart fluids} - C08K 3/04: Carbon - C10M: LUBRICATING COMPOSITIONS (well drilling compositions C09K8/02); USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION (mould release, i.e. separating, agents for metals B22C3/00, for plastics or substances in a plastic state, in general B29C33/56, for glass C03B40/02; textile lubricating compositions D06M11/00, D06M13/00, D06M15/00; immersion oils for microscopy G02B21/33) - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) ## Abstract The present invention relates to an electrorheological semisolid capable of changing the rheological characteristics by an application of voltage. The semisolid is composed of 20-70 weight. Parts of carbonaceous particulates having an average particle size of 0.1-500 .mu.m and a carbon/hydrogen atomic ratio (C/H ratio) of 1.2-5 which are dispersed in 80-30 weight % of a dispersion medium comprising a partially crosslinked electric insulating polymer having a penetration of 40-475 at 25.degree. C., or into 80-30 weight % of a dispersion medium selected from an electric insulating oil having a viscosity of 5000 to 10.sup.9 centistokes at 25.degree. C. and an electric insulating polymer having a viscosity of 5000 to 10.sup.9 centistokes at 25.degree. C. ## Claims ### Claim 1 An electrorheological semisolid comprising: 20-70 weight parts of carbonaceous particulates having an average particle size of 0.1-500 .mu.m and a carbon/hydrogen atomic ration (C/H ratio) of 1.2-5 dispersed in 80-30 weight parts of a dispersion medium comprising a partially crosslinked electric insulating polymer having a penetration of 40-475 at 25.degree. C. ### Claim 2 (depends on 1) An electrorheological semisolid according to claim 1, wherein the carbonaceous particulates have an average particle size of 1-100 .mu.m. ### Claim 3 (depends on 1) An electrorheological semisolid according to claim 1, wherein the carbonaceous particulates contains 80-97 weight % of carbon. ### Claim 4 (depends on 1) An electrorheological semisolid according to claim 1, wherein the carbonaceous particulates have a volume resistivity of 10.sup.5 -10.sup.11 .OMEGA..multidot.cm. ### Claim 5 (depends on 1) An electrorheological semisolid according to claim 1, wherein the carbonaceous particulates are selected from the group consisting of particulates of finely pulverized coal-tar pitch, petroleum pitch or pitch obtained by thermal decomposition of polyvinylchloride; carbonaceous mesophase spherules obtained by heat-treatment of these pitch or tar component to form optically anisotropic spherules and separating residual pitch component with solvents; pulverized products of these spherules; pulverized bulk mesophase obtained by heat-treatment of raw material pitches; pulverized partially crystallized pitch; and low-temperature carbonized thermosetting resins. ### Claim 6 (depends on 5) An electrorheological semisolid according to claim 5, wherein the low-temperature carbonized thermosetting resins are carbonized phenolic resin microbeads. ### Claim 7 (depends on 1) An electrorheological semisolid according to claim 1, wherein the partially crosslinked electric insulating polymer has penetration of 40-475 and a volume resistivity of 10.sup.12 -10.sup.17 .OMEGA..multidot.cm at 25.degree. C. ### Claim 8 (depends on 7) An electrorheological semisolid according to claim 7, wherein the partially crosslinked electric insulating polymer has penetration of 50-200 and a volume resistivity of 10.sup.12 -10.sup.17 .OMEGA..multidot.cm at 25.degree. C. ### Claim 9 (depends on 8) An electrorheological semisolid according to claim 8, wherein the partially crosslinked electric insulating polymer has penetration of 60-120 and a volume resistivity of 10.sup.14 -10.sup.16 .OMEGA..multidot.cm at 25.degree. C. ### Claim 10 (depends on 7) An electrorheological semisolid according to claim 7, wherein the partially crosslinked electric insulating polymer is a two-liquid type or one-liquid type silicone gel. ### Claim 11 An electrorheological semisolid comprising: 20-70 weight parts of carbonaceous particulates having an average particle size of 0.1-14 500 .mu.m and a carbon/hydrogen atomic ration (C/H ratio) of 1.2-5 dispersed in 80-30 weight parts of a dispersion medium selected from an electric insulating oil having a viscosity of 5000 to 10.sup.9 centistokes at 25.degree. C. and an electric insulating polymer having a viscosity of 5,000 to 10.sup.9 centistokes at 25.degree. C. ### Claim 12 An electrorheological semisolid according to 11, wherein the electric insulating oil or electric insulating polymer has a volume resistivity of 10.sup.10 -10.sup.17 .OMEGA..multidot.cm at 25.degree. C. ### Claim 13 (depends on 12) An electrotheological semisolid according to claim 12, wherein the electric insulating oil or electric insulating polymer has a viscosity of 10.sup.4 to 10.sup.8 centistokes and a volume resistivity of 10.sup.12 -10.sup.17 .OMEGA..multidot.cm at 25.degree. C. ### Claim 14 (depends on 13) An electrorheological semisolid according to claim 13, wherein the electric insulating oil or electric insulating polymer has a viscosity of 10.sup.4 -10.sup.6 centistokes and a volume resistivity of 10.sup.13 -10.sup.17 .OMEGA..multidot.cm at 25.degree. C. ### Claim 15 (depends on 11) An electrorheological semisolid according to claim 11, wherein the electric insulating oil or electric insulating polymer is a silicone oil, a silicone polymer or a fluorosilicone oil. ### Claim 16 (depends on 11) An electrorheological semisolid according to claim 11, wherein the carbonaceous particulates have an average particle size of 1-100 .mu.m. ### Claim 17 (depends on 11) An electrorheological semisolid according to claim 11, wherein the carbonaceous particulates contains 80-97 weight % of carbon. ### Claim 18 (depends on 11) An electrorheological semisolid according to claim 11, wherein the carbonaceous particulates have a volume resistivity of 10.sup.5 -10.sup.11 .OMEGA..multidot.cm. ### Claim 19 (depends on 11) An electrorheological semisolid according to claim 11, wherein the carbonaceous particulates are selected from the group consisting of particulates of finely pulverized coal-tar pitch, petroleum pitch or pitch obtained by thermal decomposition of polyvinylchloride; carbonaceous mesophase spherules obtained by heat-treatment of these pitch or tar component to form optically anisotropic spherules and separating residual pitch component with solvents; pulverized products of these spherules; pulverized bulk mesophase obtained by heat-treatment of raw material pitches; pulverized partially crystallized pitch; and low-temperature carbonized thermosetting resins. ### Claim 20 (depends on 19) An electrorheological semisolid according to claim 19, wherein the low-temperature carbonized thermosetting resins are carbonized phenolic resin microbeads.