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.
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