Fluorochemical composition comprising a fluorinated polymer and treatment of a fibrous substrate therewith

A fluorochemical composition having oil- and/or water-repellent properties on fibrous substrates comprising a fluorinated polymer comprising units derived from (i) a mixture of two or more fluorinated polyether monomers that differ in at least their molecular weight with at least one of said monomers in an amount of at least 90% by weight of said mixture and consisting of fluorinated polyether monomers of the formula:

• PF-Q-C(R)═CH2 (I)
• wherein PF is a perfluorinated polyether group having a molecular weight of at least 750 g/mol, R is hydrogen or alkyl of 1 to 4 carbon atoms and Q is a divalent linking group selected from the group consisting of:
• *—CH2-L1-, *—COO-L2-, *—CONRa-L2-,
• wherein L1 is a chemical bond or an organic divalent linking group, L2 is an organic divalent linking group and Ra is hydrogen or an alkyl group having 1 to 4 carbon atoms and * indicates the position where the linking group is attached to the group PF in formula (I), and (ii) one or more units derived from one or more co-monomers other than a fluorinated polyether monomer and wherein said co-monomers comprise at least one non-fluorinated monomer.