Patent ID: 7897678

Claim:
A fluorochemical urethane comprising the reaction product of: a) a polyisocyanate, b) an isocyanate-reactive perfluoropolyether compound is of the formula: R f 1 -[Q-X 2 —H] z , wherein R f 1 is a monovalent perfluorooxyalkyl group or a divalent perfluorooxyalkylene group of the formula W—R f 3 —O—R f 4 —(R f 5 ) q —, wherein W is F for monovalent perfluorooxyalkyl, and an open valence (“−”) for divalent perfluorooxyalkylene; R f 3 represents a perfluoroalkylene group, R f 4 represents a perfluoroalkyleneoxy group consisting of perfluorooxyalkylene groups having 1, 2, 3 or 4 carbon atoms or a mixture of such perfluorooxyalkylene groups, R f 5 represents a perfluoroalkylene group, and q is 0 or 1, Q is a covalent bond, or a polyvalent alkylene group of valency z, said alkylene optionally containing one or more catenary oxygen atoms, X 2 is —O—, —NR 4 — or —S—, where R 4 is H or C 1 -C 4 alkyl, z is 1 or 2, c) an oligomer of the formula X-[M 1 ] a -[M 2 ] b -S—R 3 —X 3 H, wherein X is H, or the residue of an initiator, M 1 is the residue of a (meth)acrylate monomer having a pendent silyl group, M 2 is the residue of (meth)acrylate ester monomer, R 3 is a divalent alkylene or arylene groups, or combinations thereof, said alkylene groups optionally containing one or more catenary oxygen atoms; and X 3 is —O—, —S— or —NR 4 —, where R 4 is H or C 1 -C 4 alkyl; a is at least 2, b may be 0 and a+b is 2-20, and d) optionally an isocyanate-reactive compound.