US 12,441,892 B2
Low dielectric silica powder, resin composition containing the silica powder, and method for manufacturing low dielectric silica powder
Toshio Shiobara, Annaka (JP); and Hajime Itokawa, Annaka (JP)
Assigned to SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
Filed by SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
Filed on Feb. 5, 2024, as Appl. No. 18/432,451.
Application 18/432,451 is a division of application No. 17/321,827, filed on May 17, 2021, granted, now 12,098,290.
Claims priority of application No. 2020-96051 (JP), filed on Jun. 2, 2020.
Prior Publication US 2024/0174863 A1, May 30, 2024
Int. Cl. C09C 1/30 (2006.01); C01B 33/18 (2006.01); C08K 3/36 (2006.01)
CPC C09C 1/3045 (2013.01) [C01B 33/18 (2013.01); C08K 3/36 (2013.01); C01P 2004/03 (2013.01); C01P 2004/61 (2013.01); C01P 2004/62 (2013.01); C01P 2006/40 (2013.01); C01P 2006/80 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for manufacturing a low dielectric silica powder, comprising:
heat-treating a silica powder at a temperature of 500° C. to 1500° C. to achieve 0.0005 or less of a dielectric loss tangent of the silica powder at 10 GHZ; and
etching a surface of the heat-treated silica powder with an etching solution, wherein the low dielectric silica powder has an average particle size of 0.1 to 30 μm and a dielectric loss tangent of 0.0005 or less at 10 GHz, has, inside and on a surface thereof, 200 ppm or less of a metal and/or a metal oxide in terms of mass of each metal, the metal selected from aluminum, magnesium, and titanium, and 10 ppm or less of an alkali metal and an alkaline earth metal in terms of mass of each, and wherein a hydroxy group (Si-OH) content of the low dielectric silica powder is from 135 ppm or more to 300 ppm or less in terms of mass, wherein the hydroxy group content is quantified by measuring the transmittance of a peak near 3680 cm−1 by infrared spectroscopic analysis, and wherein the hydroxy group is inner silanol.