The novel urethanes correspond to the formula I below ##STR1## in which a denotes a number from 5 to 17 and b denotes a number from 1 to 7. These urethanes are prepared by reacting the corresponding perfluoroalkylethanol/epichlorohydrin adducts with toluelene diisocyanates. The novel aqueous dispersions are essentially composed of the novel urethanes, cationic or betaine emulsifiers and non-ionic emulsifiers, water-insoluble carboxylic and/or dicarboxylic acid esters and alkanediols or polyalkanediols which can be etherified on one or both sides, in water.The novel urethanes and the novel aqueous dispersions are used to impart an oleophobic and hydrophobic finish to textiles, leather and furs. They are also suitable for the treatment of unpainted timber, for example unpainted furniture.