Fluorocarbon-containing isocyanate derivatives and soil-resist agents

A perfluoroalkyl-substituted polyisocyanate comprising the product prepared by the sequential reaction of a polyisocyanate containing two or more reactive isocyanate groups per molecule with a terminally unsaturated alkenyl or alkynyl Zerwitinoff hydrogen-containing compound, perfluoro-alkylating the resulting alkenylated or alkynylated polyisocyanate by reaction with perfluoroalkyl iodides at a pH between 2 and 8, and dehydroiodinating the resulting perfluoroalkyl-substitured polyisocyanate so as to effect elimination of hydrogen iodide therefrom.