PURPOSE: To prepare a water and oil repellant having excellent defoaming property, by adding a polyether type fluorine-based oil to a fluorine-based solvent type water and oil repellant.
CONSTITUTION: The water and oil repellant is prepared by adding a polyether type fluorine-based oil to a fluorine-based solvent type water and oil repellant in an amount of 0.01W100, pref. 0.1W10wt% of solid content of the repellant. A preferred water and oil repellant is a soln. of a fluorine-contg. polymer which contains monomers of formulas I and II as structural units (where Rf is perfluoroalkyl of formula III; R1 is H or methyl; R2 is alkylene of formula IV; R3 is H or alkyl of formula V; n is 5W16; l is 1W18). A preferred fluorine- based solvent type water and oil repellant is a polyether type fluorine-contg. polymer or copolymer, esp. containing hexafluoropropylene oxide as main structural unit.