Production of an aqueous dispersion, useful as an adhesive, comprises emulsion polymerization of ethylenically unsaturated monomers in the presence of a dispersed fine particulate inorganic solid

摘要

Production of an aqueous dispersion of particles comprising a polymer and a fine particulate inorganic solid (composite particles) comprises emulsion polymerization of a mixture of ethylenically unsaturated monomers in an aqueous medium by means of a radical polymerization inhibitor in the presence of a dispersed fine particulate inorganic solid and a dispersing agent. Production of an aqueous dispersion (I) of particles comprising a polymer and a fine particulate inorganic solid (composite particles) comprises emulsion polymerization of a mixture of ethylenically unsaturated monomers in an aqueous medium by means of a radical polymerization inhibitor in the presence of at least one dispersed fine particulate inorganic solid and a dispersing agent. The process is effected using (A) a stable aqueous dispersion of an inorganic solid having an initial solids concentration of at least 1 wt.% and whereby more than 90 wt.% of the original dispersed solid remains in dispersed form one hour after its preparation and having a weight average diameter of no greater than 100 nm. (B) the dispersed solid particles have an electrophoretic mobility that is different to the null point in an aqueous standard alkali chloride solution at a pH corresponding to the pH of the aqueous reaction medium at the start of the emulsion polymerzation and (C) the mixture of ethylenically unsaturated monomers comprises greater than 0 wt.% to no greater than 4 wt.% of a monomer (A) that either contains at least an acid group and/or corresponding anion if the dispersed solid inorganic particles have a positive electrophoretic mobility or contain an amino-, amido-, ureido- or N-heterocyclic group and/or an alkylated ammonium derivative protonated at the nitrogen group if the dispersed solid inorganic particles have a negative electrophoretic mobility. Independent claims are included for (i) the aqueous dispersion (I) of composite particles, and (ii) a composite particle powder prepared by drying of the aqueous dispersion (I).