Patent 7553985 was granted and assigned to E.I. Du Pont De Nemours And Company on June, 2009 by the United States Patent and Trademark Office.
A composition of formula I[Rf(CH2)m(O)n]x-AwhereinRf is a straight or branched perfluoroalkyl group having from about 2 to about 20 carbon atoms, or a mixture thereof,m is a positive integer equal to or greater than 3,n is 0 or 1,x is 1 to about 3,A is —P(O)(OR1)y(OM+)3−y−x, —C(O)CH(SO3−M+)CH2C(O)—, —(CH2CH2O)d(CH2CHR2O)eR3, or —SO2B,M+ is an alkali metal ion, NH4+, or NH2+(CH2CH2OH)2,B is N(R2)2 or N(CH2CH3)(CH2CH2OH),R1 is C1 to C3 alkyl,R2 is C1 to C4 alkyl,R3 is H or CH3,y is 0 to about 1,d is 0 to about 16,e is 0 to about 16, provided that (d+e) is from about 3 to about 16 is disclosed.