US 12,168,704 B2
Method for producing an aqueous polymer dispersion from vinylaromatic compound and conjugated aliphatic diene
Dirk Lawrenz, Ludwigshafen am Rhein (DE); Nico Veling, Ludwigshafen am Rhein (DE); and Carmen-Elena Cimpeanu, Ludwigshafen am Rhein (DE)
Assigned to BASF SE, Ludwigshafen am Rhein (DE)
Appl. No. 17/299,657
Filed by BASF SE, Ludwigshafen am Rhein (DE)
PCT Filed Nov. 21, 2019, PCT No. PCT/EP2019/082145
§ 371(c)(1), (2) Date Jun. 3, 2021,
PCT Pub. No. WO2020/114797, PCT Pub. Date Jun. 11, 2020.
Claims priority of application No. 18209822 (EP), filed on Dec. 3, 2018.
Prior Publication US 2022/0033550 A1, Feb. 3, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C08F 2/22 (2006.01); C08F 212/08 (2006.01); C08F 236/06 (2006.01); C08K 3/013 (2018.01); C08K 5/14 (2006.01); C09D 109/06 (2006.01)
CPC C08F 212/08 (2013.01) [C08F 2/22 (2013.01); C08F 236/06 (2013.01); C08K 3/013 (2018.01); C08K 5/14 (2013.01); C09D 109/06 (2013.01)] 8 Claims
 
1. A process for producing an aqueous polymer dispersion by free- radically initiated aqueous emulsion polymerization, which comprises polymerizing, in an aqueous medium,
a) 40 to 75 parts by weight of at least one vinylaromatic compound and
b) 24.9 to 59.9 parts by weight of at least one conjugated aliphatic diene
c) 0.1 to 10 parts by weight of at least one monomer comprising acid groups and
d) 0 to 20 parts by weight of at least one other monoethylenically unsaturated monomer, the amounts of the monomers (a) to (d) adding up to 100 parts by weight, in a monomer feed process in the presence of a free-radical initiator, with the proviso that
the vinylaromatic compound is metered under polymerization conditions in a continuous mass flow over a period of at least 120 minutes,
the metering of the conjugated aliphatic diene is started at a time at which at least 5% and not more than 30% of the vinylaromatic compound has already been metered in a continuous mass flow and
optionally, the polymerization is initiated in an aqueous polymerization mixture comprising up to 5% of the vinylaromatic compound and comprising no aliphatic diene.