A process is described for preparing a stable aqueous emulsion of a polymer derived from an alkyl perfluoralkanoate and an alkylenimine, employing 2.5-10 percent (based on total solvent weight) of a water-miscible polymer solvent, and special emulsifiers. When fibrous cellulosic materials are treated with such emulsions using about from 1 to about 10 weight percent (based on the total emulsion weight) of the fluorinated ester, the resultant treated materials are rendered durably oleophobic and slightly hydrophobic. These desirable properties may be imparted by a simple drying step without resorting to a high temperature cure step.
