US 12,359,130 B2
Flame retardant powder for magnetic member, and polymer composition
Kodai Miura, Himeji (JP); Toshiyuki Sawada, Himeji (JP); and Ryosuke Ochi, Himeji (JP)
Assigned to Sanyo Special Steel Co., Ltd., Himeji (JP)
Appl. No. 17/424,225
Filed by Sanyo Special Steel Co., Ltd., Himeji (JP)
PCT Filed Dec. 17, 2019, PCT No. PCT/JP2019/049422
§ 371(c)(1), (2) Date Jul. 20, 2021,
PCT Pub. No. WO2020/153050, PCT Pub. Date Jul. 30, 2020.
Claims priority of application No. 2019-007663 (JP), filed on Jan. 21, 2019.
Prior Publication US 2022/0119713 A1, Apr. 21, 2022
Int. Cl. C09K 21/02 (2006.01); C08K 3/016 (2018.01); C08K 3/11 (2018.01); C08L 101/00 (2006.01); C22C 38/02 (2006.01)
CPC C09K 21/02 (2013.01) [C08K 3/016 (2018.01); C08K 3/11 (2018.01); C08L 101/00 (2013.01); C22C 38/02 (2013.01); C22C 2202/02 (2013.01)] 2 Claims
 
1. A flame retardant powder for magnetic members, comprising a plurality of flaky particles,
wherein the flaky particle is composed of an Fe—Si based alloy comprising 7% by mass or more and 12% by mass or less of Si, and a content of Si in terms of percentage by mass, P(Si), in the alloy and a flame retardancy parameter, PNF, satisfy following mathematical formulae (I) and (II):
(−0.97×P(Si)+13.0)<PNF≤10  (I)
PNF=D50×TD/ρ  (II)
wherein D50 represents a median diameter of the powder, TD represents a tap density of the powder, and ρ represents a true density of the powder,
wherein the flame retardant powder has a saturation magnetic flux density of 1.3 T or more,
wherein the flame retardant powder has a coercive force Hc of 550 A/m or more, and
wherein the tap density TD of the flame retardant powder is 0.6 g/cm3 or more and 1.7 g/cm3 or less.