US Patent 7732545 Process for preparing aqueous dispersion

An aqueous dispersion is prepared by subjecting (meth)acrylate containing a polyfluoroalkyl group and a polymerizable monomer containing no fluorine atom to an emulsification treatment in the presence of a surfactant and a polypropyleneglycol-based compound having a molecular weight of 250 to 5,000, followed by copolymerization reaction in the presence of a polymerization initiator. The resulting aqueous dispersion, even if prepared from (meth)acrylate copolymer containing mixed perfluoroalkyl groups including perfluoroalkyl groups having 12 or more carbon atoms as polyfluoroalkyl groups, has a distinguished emulsion stability and thus can be effectively used as a water and oil repellent, etc.