POLYURETHANES CONTAINING PERFLUORINATED ALKYL GROUPS AND PROCESS FOR THEIR PRODUCTION

To render surfaces, such as of textile fabrics and fibers, repellent to oil and/or water, they are treated with novel polyurethanes containing perfluoroalkyl ligands and having as recurring structural units and/or with chain ends of the formula -YAm' in which X, Y and Z each independently is the skeletal radical of an aliphatic or aromatic di- or polyisocyanate, RF is a difunctional radical containing at least one perfluoroalkyl ligand, the perfluoroalkyl chain comprising 3 to 30 carbon atoms and, in addition to fluorine atoms, containing at most one hydrogen or chlorine atom to two carbon atoms; and the perfluoroalkyl chain optionally being interrupted by oxygen, n is the number of isocyanate groups on the skeletal radical X and is an integer from 2 to 25, A is an isocyanate group protected by a blocking agent, m is the number of blocked isocyanate groups A on the skeletal radical Y and is an integer from 1 to 5, E is O, S or -NR'-, R' is H, alkyl or aryl, R is the radical of a compound containing at least two alcohol, amine and/or thiol groups, a and b are the number of -OH, -NR'H or -SH functions in the alcohols, amines or thiols R(EH)(a+b) used and each is an integer from 0 to 10, and p is the number of isocyanate groups on the skeletal radical Z and is an integer from 0 to 25. Subsequent heating removes the end blocks and effects chemical fixation on the surface.