Patent ID: 8642177

Claim:
A method of providing acid etch resistance, water repellency, oil repellency and stain resistance to a substrate surface comprising contacting the substrate surface with a copolymer of formula (I) wherein R f is C 1 to C 10 linear or branched fluoroalkyl, optionally interrupted by one or more —O—, —CH 2 —, —CFH—, or combinations thereof; Q is an alkylene of 1 to about 15 carbon atoms, hydroxyalkylene of 3 to about 15 carbon atoms, —(C n H 2n )(OC q H 2q ) m —, —(C n H 2n )(NR′) z —SO 2 —NR′(C n H 2n )—, or —CONR′(C n H 2n )—, wherein each R′ is independently H or an alkyl of from 1 to about 4 carbon atoms, n is independently 1 to about 15, q is 2 to about 4, m is 1 to about 15, and z is 0 or 1; R a is a C 3 to C 4 branched alkyl; M is H, NH 4 , Na, Li, Cs, K, HNR 3 or mixtures thereof; R is C 1 to C 4 linear or branched alkyl; a is an integer from about 20 to about 50 mol %; b is an integer from about 5 to about 35 mol %; and c is an integer from about 15 to about 60 mol %; wherein the sum of a+b+c is equal to 100%.