Process for preparing core-shell emulsion polymer particles and resulting product containing such particles

摘要: The present invention relates to a process for preparing polymeric particles which is specially designed be served as an opacifying agent in coating compositions such water-borne paints, paper and molding have white or light color shades. In more detailed description, this concerned with the making aqueous dispersion of core-shell emulsion polymer comprising (1) core by polymerizing carboxylic acid monomers other monoethylenically unsaturated monomers, (2) encapsulating said rigid shell shell-forming presence particles, are fed manner that compositional contents entering polymerization zone changing gradually thoughout period monomer feeding, (3) neutralizing base so swell form which, when dried, contain at least one void.