US 12,134,564 B2
Precipitated silica and process for its manufacture
Cyril Chomette, Mérignac (FR); Frédéric Colbeau-Justin, Collonges au Mont d'Or (FR); Fabien Stocklouser, Francheville (FR); Cédric Boivin, Chasselay (FR); and Thomas Chaussee, Cailloux-sur-Fontaines (FR)
Assigned to RHODIA OPERATIONS, Lyons (FR)
Appl. No. 17/291,030
Filed by RHODIA OPERATIONS, Aubervilliers (FR)
PCT Filed Nov. 6, 2019, PCT No. PCT/EP2019/080397
§ 371(c)(1), (2) Date May 4, 2021,
PCT Pub. No. WO2020/094717, PCT Pub. Date May 14, 2020.
Claims priority of application No. 18306462 (EP), filed on Nov. 8, 2018.
Prior Publication US 2021/0371289 A1, Dec. 2, 2021
Int. Cl. C01B 33/193 (2006.01); B60C 1/00 (2006.01); C08K 3/36 (2006.01); C08L 101/00 (2006.01); B82Y 40/00 (2011.01)
CPC C01B 33/193 (2013.01) [B60C 1/00 (2013.01); C08K 3/36 (2013.01); C08L 101/00 (2013.01); B82Y 40/00 (2013.01); C01P 2004/64 (2013.01); C01P 2006/12 (2013.01)] 2 Claims
 
1. A process for the preparation of a precipitated silica comprising:
a CTAB surface area SCTAB equal to or greater than 160 m2/g,
a median particle size d50, measured by centrifugal sedimentation, such that |d50|>25000/|SCTAB| (I), wherein |d50| represents the numerical value of the median particle size d50 measured by centrifugal sedimentation and expressed in nm and |SCTAB| represents the numerical value of the CTAB surface area SCTAB expressed in m2/g, and
an aluminum content not exceeding 4500 ppm,
said process comprising:
(i) providing a starting solution having a pH from 2.0 to 5.0
(ii) simultaneously adding a silicate and an acid to said starting solution such that the pH of the reaction medium is maintained in the range from 2.0 to 5.0,
(iii) stopping the addition of the acid and of the silicate and adding a base to the reaction medium to raise the pH of said reaction medium to a value from 7.0 to 10.0,
(iv) simultaneously adding to the reaction medium a silicate and an acid, such that the pH of the reaction medium is maintained in the range from 7.0 to 10.0, and
(v) stopping the addition of the silicate while continuing the addition of the acid to the reaction medium to reach a pH of the reaction medium of less than 5.5 and obtaining a suspension of precipitated silica,
wherein the amount of silicate added to the reaction medium during step (ii) is more than 55% of the total amount of silicate required for the reaction.