US 12,378,431 B2
Process for preparing aqueous polymer dispersions
Jurgen Scheerder, Buren (NL); and Remy Paul Marie Dollekens, Den Bosch (NL)
Assigned to Covestro (Netherlands) B.V., Geleen (NL)
Appl. No. 17/916,218
Filed by Covestro (Netherlands) B.V., Geleen (NL)
PCT Filed Mar. 22, 2021, PCT No. PCT/EP2021/057232
§ 371(c)(1), (2) Date Sep. 30, 2022,
PCT Pub. No. WO2021/197883, PCT Pub. Date Oct. 7, 2021.
Claims priority of application No. 20167609 (EP), filed on Apr. 1, 2020.
Prior Publication US 2023/0140735 A1, May 4, 2023
Int. Cl. C09D 7/42 (2018.01); C09D 5/02 (2006.01); C09D 125/14 (2006.01)
CPC C09D 125/14 (2013.01) [C09D 5/022 (2013.01); C09D 7/42 (2018.01)] 64 Claims
OG exemplary drawing
 
1. A process for preparing an aqueous polymer dispersion, wherein the process comprises:
a free-radically initiated emulsion polymerization in an aqueous medium, in the presence of at least one vinyl polymer A, to obtain a polymer B comprising a vinyl polymer phase B1 with a glass transition temperature, calculated by means of the Fox equation, of from −20 to +15° C. and a vinyl polymer phase B2 with a glass transition temperature, calculated by means of the Fox equation, of from +50 to +110° C., with the proviso that the difference in glass transition temperature between polymer B1 and polymer B2 is at least 40° C.,
wherein:
the weight ratio of polymer B1 to polymer B2 is from 80:10 to 10:20,
the at least one polymer A is obtained by a process comprising:
free-radically initiated bulk or solution polymerizing of:
from 5 to 25 wt. % of at least one carboxylic acid functional ethylenically unsaturated monomer A1, and
from 75 to 95 wt. % of at least one ethylenically unsaturated monomer A2 different than monomer A1,
where the amounts are given relative to the total weight of monomers charged in the polymerization to prepare the vinyl polymer A,
the glass transition temperature of the at least one vinyl polymer A, calculated by means of the Fox equation, is from 40 to 150° C.,
the weight average molecular weight of the at least one polymer A, determined via SEC, is from 1000 to 70000 g/mol,
the weight average molecular weight of the polymer A is lower than the weight average molecular weight of the polymer B, determined via SEC, and
the weight ratio of polymer A to polymer B is from 10:90 to 40:60.