US Patent 7799859 Surfactant composition

A surfactant composition has good emulsifiability for monomer(s), and can provide a polymer emulsion (herein after simply called “the emulsion”) of good stability while decreasing coagulations of polymer particles in the emulsion. The surfactant composition contains the following components (A) and (B): (A) a reactive surfactant containing at least one polymerizable double-bond group and at least one ionic group in a molecule, and (B) a nitrogen compound insoluble or slightly soluble in ethanol. A weight ratio (A:B) of the component (A) to the component (B) is from 100:0.03 to 100:1.0.