PROCESS FOR THE PREPARATION OF A REDISPERSIBLE CORE-SHELL POLYMER POWDER

摘要

Redispersible polymer powders made by core-shell polymers hVING an alkali-soluble emulsion polymer shell and an aqueous-insoluble emulsion polymer core wherein the core and the shell polymers are chemically grafted by utilizing a polyfunctional compound. The core-shell polymers are produced by a two-stage sequential emulsion polymerization process in which an alkali-insoluble emulsion polymer core is polymerized in the presence of an alkali-solubilized emulsion polymer. When the core-shell polymer powders of this invention are employed as a cement modifier, improvements in the powder physical properties and cement mortar properties are realized.