# US 12,215,217 B2 · Composition for acoustic member and acoustic member > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,215,217 B2 - Document ID: US12215217B2 - Status: Granted - Kind: B2 - Application number: 17/569,449 - Filed: 2022-01-05 - Published: 2022-04-28 - Granted: 2025-02-04 - Earliest claimed: 2019-07-08 - Assignees: Yamaha Corporation - Applicants: Yamaha Corporation - Inventors: Tomoya Miyata - Web page: https://patentgrep.com/patent/US12215217B2 ## CPC - C08L 23/22: Copolymers of isobutene; Butyl rubber; Homopolymers or copolymers of other iso-olefins - H04R 7/20: Securing diaphragm or cone resiliently to support by flexible material, springs, cords, or strands - H04R 1/02: Casings; Cabinets {; Supports therefor;} Mountings therein (H04R1/28 takes precedence {; attachments for microphones H04R1/08; mounting of transducers in earpieces H04R1/1075}) - H04R 1/083: {Special constructions of mouthpieces} - H04R 31/003: {for diaphragms or their outer suspension} - H04R 31/006: {Interconnection of transducer parts (of diaphragm and outer suspension by moulding H04R31/003)} - C08K 3/013: Fillers, pigments or reinforcing additives - H04R 2201/029: Manufacturing aspects of enclosures transducers - H04R 2307/204: Material aspects of the outer suspension of loudspeaker diaphragms - H04R 2410/03: Reduction of intrinsic noise in microphones - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) ## Abstract A composition for an acoustic member includes a non-diene butyl rubber, and a liquid polymer having a molecular weight of 1,000 to 120,000. A difference in an SP value between the liquid polymer and the butyl rubber is within ±0.5. ## Claims ### Claim 1 A composition for an acoustic member comprising: a non-diene butyl rubber; and a liquid polymer, an internal loss (tan δ) in a dynamic viscoelasticity measurement of a first crosslinked product of the composition measured under conditions of 20° C., 0.1% dynamic strain, and 1 Hz frequency being increased by 120% or more as compared with a second crosslinked product formed by removing the liquid polymer from the composition, and A hardness of the first crosslinked product according to JIS K6253 being 60% or more and 90% or less of A hardness of the second crosslinked product, and a rate of change of the A hardness of the first crosslinked product being less than 10% before and after holding at 110° C. for 300 hours. ### Claim 2 A composition for an acoustic member comprising: a non-diene butyl rubber; and a liquid polymer having a molecular weight of 1,000 to 120,000, a difference in an SP value between the liquid polymer and the butyl rubber being within ±0.5, and a rate of change of A hardness according to JIS K6253 for a first crosslinked product of the composition being less than 10% before and after holding at 110° C. for 300 hours. ### Claim 3 (depends on 2) The composition for an acoustic member according to claim 2, wherein a crosslinked product of the composition is free of a sea-island structure made of a resin material. ### Claim 4 (depends on 2) The composition for an acoustic member according to claim 2, wherein 1 to 100 parts by mass of the liquid polymer is included relative to 100 parts by mass of the butyl rubber. ### Claim 5 (depends on 2) The composition for an acoustic member according to claim 2, wherein the liquid polymer contains the same structural unit as the butyl rubber. ### Claim 6 (depends on 2) The composition for an acoustic member according to claim 2, wherein the composition further contains a vulcanizing agent and a filler. ### Claim 7 (depends on 2) An acoustic member obtained by crosslinking and molding the composition for an acoustic member according to claim 2. ### Claim 8 (depends on 7) The acoustic member according to claim 7, wherein the acoustic member is an edge of a speaker. ### Claim 9 (depends on 7) The acoustic member according to claim 7, wherein the acoustic member is an insulator that supports a microphone capsule of a handheld microphone.