US 12,215,217 B2
Composition for acoustic member and acoustic member
Tomoya Miyata, Shizuoka (JP)
Assigned to YAMAHA CORPORATION, Shizuoka (JP)
Filed by Yamaha Corporation, Shizuoka (JP)
Filed on Jan. 5, 2022, as Appl. No. 17/569,449.
Application 17/569,449 is a continuation of application No. PCT/JP2019/037801, filed on Sep. 26, 2019.
Claims priority of application No. 2019-127198 (JP), filed on Jul. 8, 2019.
Prior Publication US 2022/0127442 A1, Apr. 28, 2022
Int. Cl. C08L 23/22 (2006.01); H04R 1/02 (2006.01); C08K 3/013 (2018.01)
CPC C08L 23/22 (2013.01) [H04R 1/02 (2013.01); C08K 3/013 (2018.01); H04R 2201/029 (2013.01)] 9 Claims
OG exemplary drawing
 
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.