Emulsion polymerizations are described in which the monomers include an
ethylenically unsaturated ammonium phosphate ester monomer. The processes
may be conducted with high total solids, to produce a polymer latex having
a solids content in the range 20 to 60%, for instance in the range 25 to
50% by weight. Preferably comonomers include lower alkyl and higher alkyl
methacrylate selected to give desirable glass transition temperatures and
coalescing films, zwitterionic comonomers, polyethoxylated comonomers to
confer desired biocompatibility and latex stability as well as good
wetting for a film formed of the polymer and may contain crosslinking
monomers, reactive monomers, anionic monomers and/or cationic monomers.
The latexes are stable, even when the process is carried out in the
substantial absence of non-polymerizable emmulsifier. Coatings formed from
the latexes containing zwitterionic comonomer have good biocompatibilizing
properties.
