US 12,319,762 B2
Olefin-based rubber composition
Kazuya Hashimoto, Kanagawa (JP)
Assigned to NOK CORPORATION, Tokyo (JP)
Appl. No. 17/799,461
Filed by NOK CORPORATION, Tokyo (JP)
PCT Filed Jan. 26, 2021, PCT No. PCT/JP2021/002606
§ 371(c)(1), (2) Date Aug. 12, 2022,
PCT Pub. No. WO2021/161777, PCT Pub. Date Aug. 19, 2021.
Claims priority of application No. 2020-022722 (JP), filed on Feb. 13, 2020.
Prior Publication US 2023/0070164 A1, Mar. 9, 2023
Int. Cl. C08K 3/26 (2006.01); C08F 210/18 (2006.01); C08K 5/14 (2006.01)
CPC C08F 210/18 (2013.01) [C08K 3/26 (2013.01); C08K 5/14 (2013.01); C08K 2003/267 (2013.01); C08K 2201/001 (2013.01); C08K 2201/005 (2013.01); C08K 2201/014 (2013.01)] 4 Claims
 
1. An olefin-based rubber composition comprising:
an ethylene-α-olefin-nonconjugated polyene copolymer;
at least two types of magnesium carbonate; and
a cross-linking agent,
wherein
one of the two types of magnesium carbonate is small-particle-size magnesium carbonate having 0.3 to 5 μm of an average particle size, and the other one of the two types of magnesium carbonate is large-particle-size magnesium carbonate having 7 to 60 μm of average particle size, and a parts by mass ratio of the small-particle-size magnesium carbonate to the large-particle-size magnesium carbonate is 25/80 to 80/20;
a total content of the two types of magnesium carbonate relative to 100 parts by mass of the ethylene-α-olefin-nonconjugated polyene copolymer is 400 to 1200 parts by mass; and
the olefin-based rubber composition after cross-linking has:
a Shore A hardness of 80 or less which id measured in compliance with JIS K 6253-3:2012 by using Durometer type A; and
a thermal conductivity of 2.0 W/m·K or more which is measured incompliance with ASTM D7984.