# US 11,908,601 B2 · Magnetic responsiveness composite material and composition including the composite material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,908,601 B2 - Document ID: US11908601B2 - Status: Granted - Kind: B2 - Application number: 17/228,896 - Filed: 2021-04-13 - Published: 2021-10-21 - Granted: 2024-02-20 - Earliest claimed: 2020-04-15 - Assignees: Somar Corporation - Applicants: Somar Corporation - Inventors: Hirohisa Ishizaki; Akira Ochiai - Web page: https://patentgrep.com/patent/US11908601B2 ## CPC - H01F 1/445: {the magnetic component being a compound, e.g. Fe3O4 (H01F1/447 takes precedence)} - H01F 1/447: {characterised by magnetoviscosity, e.g. magnetorheological, magnetothixotropic, magnetodilatant liquids (electrorheological fluids C10M171/001)} - H01F 1/28: dispersed or suspended in a bonding agent - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES ## Abstract There is provided a magnetic responsiveness composite material capable of increasing viscosity by applying a magnetic field when compounded together with a liquid in a composition. The magnetic responsive composite material comprises first particles as core particles composed of a nonmagnetic inorganic material and second particles composed of a magnetic material adhering to at least a part of surfaces of the first particles. A lipophilic treatment agent is applied to at least a part of surfaces of the second particles. The second particles satisfy a relationship of having a smaller average particle diameter than that of the first particles. A lipophilic treatment agent is preferably at least one kind selected from coupling agents and surfactants. ## Claims ### Claim 1 A composition comprising a liquid and a magnetic responsiveness composite material suspended in the liquid, wherein the liquid is a liquid resin material, the magnetic responsiveness composite material comprises: first particles as core particles composed of a nonmagnetic inorganic material; and second particles composed of a magnetic material adhered to at least a part of surfaces of the first particles, when an average particle diameter of the first particles is D1 and an average particle diameter of the second particles is D2, a relationship of D1>D2 is satisfied, a lipophilizing treatment agent adheres to at least a part of surfaces of the second particles. ### Claim 2 (depends on 1) The composition according to claim 1, wherein the liquid resin material consists of one of a thermoplastic resin and a thermosetting resin. ### Claim 3 (depends on 1) The composition according to claim 1, wherein the lipophilizing treatment agent is at least one kind selected from coupling agents and surfactants. ### Claim 4 (depends on 3) The composition according to claim 3, wherein the surfactants are saturated fatty acids or salts thereof or unsaturated fatty acids or salts thereof. ### Claim 5 (depends on 4) The composition according to claim 4, wherein D1 is 10 times D2 or more and 1000 times D2 or less. ### Claim 6 (depends on 5) The composition according to claim 5, wherein a ratio of the second particles in a sum of the first particles and the second particles is 5 wt % or more and 50 wt % or less. ### Claim 7 (depends on 6) The composition according to claim 6, wherein a content of the second particles in the magnetic responsiveness composite material is 5 wt % to 50 wt % of a total mass of the magnetic responsiveness composite material, and a viscosity during excitation when a magnetic field of a direct current of 0.8 T is applied to the composition in an atmosphere of 25° C. is at least 2.5 times a viscosity of the composition before excitation. ### Claim 8 (depends on 7) The composition according to claim 7, wherein the magnetic responsiveness composite material is a dry blended product of the first particles and the second particles. ### Claim 9 (depends on 1) The composition according to claim 1, wherein D1 is 10 times D2 or more and 1000 times D2 or less. ### Claim 10 (depends on 3) The composition according to claim 3, wherein D1 is 10 times D2 or more and 1000 times D2 or less. ### Claim 11 (depends on 1) The composition according to claim 1, wherein a ratio of the second particles in a sum of the first particles and the second particles is 5 wt % or more and 50 wt % or less. ### Claim 12 (depends on 3) The composition according to claim 3, wherein a ratio of the second particles in a sum of the first particles and the second particles is 5 wt % or more and 50 wt % or less. ### Claim 13 (depends on 4) The composition according to claim 4, wherein a ratio of the second particles in a sum of the first particles and the second particles is 5 wt % or more and 50 wt % or less. ### Claim 14 (depends on 1) The composition according to claim 1, wherein a content of the second particles in the magnetic responsiveness composite material is 5 wt % to 50 wt % of a total mass of the magnetic responsiveness composite material, and a viscosity during excitation when a magnetic field of a direct current of 0.8 T is applied to the composition in an atmosphere of 25° C. is at least 2.5 times a viscosity of the composition before excitation. ### Claim 15 (depends on 1) The composition according to claim 1, wherein the magnetic responsiveness composite material is a dry blended product of the first particles and the second particles. ### Claim 16 (depends on 3) The composition according to claim 3, wherein the magnetic responsiveness composite material is a dry blended product of the first particles and the second particles. ### Claim 17 (depends on 4) The composition according to claim 4, wherein the magnetic responsiveness composite material is a dry blended product of the first particles and the second particles.