US 12,240,982 B2
Process for preparing a surface-treated calcium carbonate material
Samuel Rentsch, Spiegel bei Bern (CH); Fabio Ippolito, Vordemwald (CH); and Roman Marty, Allschwil (CH)
Assigned to OMYA INTERNATIONAL AG, Oftringen (CH)
Appl. No. 17/310,501
Filed by OMYA INTERNATIONAL AG, Oftringen (CH)
PCT Filed Feb. 24, 2020, PCT No. PCT/EP2020/054724
§ 371(c)(1), (2) Date Aug. 6, 2021,
PCT Pub. No. WO2020/173848, PCT Pub. Date Sep. 3, 2020.
Claims priority of application No. 19159398 (EP), filed on Feb. 26, 2019.
Prior Publication US 2022/0162450 A1, May 26, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C08K 9/04 (2006.01); C08J 3/22 (2006.01); C09C 1/02 (2006.01); C09C 3/00 (2006.01); C09C 3/04 (2006.01); C09C 3/08 (2006.01)
CPC C09C 1/021 (2013.01) [C08J 3/226 (2013.01); C08K 9/04 (2013.01); C09C 3/006 (2013.01); C09C 3/041 (2013.01); C09C 3/043 (2013.01); C09C 3/08 (2013.01); C01P 2004/61 (2013.01); C01P 2004/62 (2013.01); C08J 2323/00 (2013.01); C08K 2201/005 (2013.01)] 26 Claims
 
1. A process for preparing a surface treated calcium carbonate-comprising material for use in polymer applications comprising the steps of:
a) providing water;
b) providing at least one calcium carbonate-comprising material;
c) providing at least one copolymer (P) used as grinding aid agent prepared from the polymerisation reaction of
at least one compound selected from the group consisting of acrylic acid, methacrylic acid, salts thereof, and combinations thereof, and
at least one non-ionic compound selected from the group consisting of hydroxyethylacrylate, hydroxypropylacrylate, hydroxyethylmethacrylate, hydroxypropylmethacrylate, C1-C5 esters of acrylic acid, C1-C5 esters of methacrylic acid, and combinations thereof,
one or more of the least one copolymer (P) having
i) an average molecular weight (Mw) as measured by gel permeation chromatography (GPC) from 4 000 to 20 000 g/mol, and
ii) a Polydispersity Index (PI) as measured by gel permeation chromatography (GPC) of between 1.5 and 4.0, and
iii) carboxylic acid functions that are totally or partially neutralized (A) by Na+ in an amount of 70 mol-% and (B) by Na+, K+, Li+ or combinations thereof in an additional amount from 10 to 30 mol-%;
d) forming an aqueous suspension by mixing the water of step a), the at least one calcium carbonate comprising material of step b) and the at least one copolymer (P) of step c);
e) wet grinding the at least one calcium carbonate-comprising material in the aqueous suspension of step d) in the presence of the at least one copolymer (P) in at least one wet grinding step until the at least one calcium carbonate-comprising material has a weight median particle size d50 from 0.1 μm to 3 μm as determined by the sedimentation method; and
f) up-concentrating or dewatering the aqueous suspension obtained in step e) to achieve a higher solids content than that of step e) and the solids content achieved in step f) is at least 70 wt.-%, based on the total weight of the aqueous suspension; and
g) drying the aqueous suspension obtained in step f) to achieve a calcium carbonate-comprising material having a moisture content of ≤0.5 wt.-%, based on the total dry weight of the calcium carbonate-comprising material; and
h) surface treating the calcium carbonate-comprising material obtained in step g) with at least one hydrophobizing agent.