The present invention relates to a process for preparing an aqueous
polymer dispersion comprising: preparing a dispersant co-polymer of a
monomer mixture (M) by polymerising the monomer mixture (M) in a reaction
medium which is substantially free from organic solvents and/or
substantially free from monomers which are not soluble in water, the
monomer mixture (M) comprises at least one cationic vinyl monomer
(m.sub.3) and at least one monomer (m.sub.4) which is tetrahydrofurfuryl
acrylate, tetrahydrofurfuryl methacrylate, or a monomer of the general
formula (I): wherein R.sub.1 is hydrogen or methyl, R.sub.2 is hydrogen
or C.sub.1-C.sub.2 alkyl, R.sub.3 is hydrogen, C.sub.1-C.sub.4 alkyl,
phenyl, or benzyl, n=1 to 4, and x=1 to 50, and then, polymerising one or
more water-soluble monomers (m) in an aqueous solution of a salt in the
presence of the obtained dispersant polymer. The invention also relates
to an aqueous polymer dispersion, use of the dispersion and a process for
the production of paper.