Fluorochemical composition comprising a urethane having a fluorochemical oligomer and a hydrophilic segment to impart stain release properties to a substrate

A method for preparing a fluorochemical composition comprising a urethane by reacting:

• (A) a fluorochemical oligomer of formula (I)
• MfmMn—Q1—T1 (I)
• wherein:
• MfmMn represents a fluorochemical oligomer comprising m units derived from a fluorinated monomer and n units derived from a fluorine free monomer and wherein the fluorinated monomers may be the same or different and wherein the fluorine free monomers may be the same or different;
• m represents a value of 2 to 40;
• n represents a value of 0 to 20;
• T1 is selected from the group consisting of OH or NH2 moieties;
• and
• Q1 and T1 together represent the organic residue obtained by removing a hydrogen atom from a chain transfer agent that is functionalized with T1;
• (B) a mono-functional compound reactive with an isocyanate and comprising a poly(oxyalkylene) group;
• (C) optionally an isocyanate blocking agent or fluorine free oligomer;
• and
• (D) optionally an isocyanate reactive compound other than said fluorochemical oligomer, said isocyanate blocking agent, said fluorine free oligomer and said mono-functional compound;
• with
• (E) di-isocyanate or tri-isocyanate;
• such that 33% to 67% of the number of isocyanate groups are reacted with said fluorochemical oligomer according to formula (I), 33% to 67% of the number of isocyanate groups are reacted with said monofunctional compound, 0 to 33% of the number of isocyanate groups are reacted with an isocyanate blocking agent or a fluorine-free oligomer and 0 to 10% of the number of isocyanate groups are reacted with said isocyanate-reactive compound.