Process for sizing paper with anionic hydrophobic sizing agents and cationic retention aids

摘要

Sizing agents, which are novel compounds and contain at least one anionic or acidic sulfonylcarbonylimide group which may be in salt form and at least two hydrophobic substituents of which at least two are linked to each other through a bridge member of the formula -CO-NH-A1-(SO2-NH-CO)t, where A1 is a divalent or trivalent aliphatic, cycloaliphatic or aromatic radical of up to 10 carbon atoms, and t is 1 or 2, are particularly suitable, together with commercially available retention aids, for use in a process for sizing paper or cardboard.