Patent ID: 6224981
Filing Date: 2001-05-01
Classification: C08F,Y10T

Abstract:
A water-redispersible powder comprising film-forming polymers which are water-insoluble and with a ""core/shell"" structure, the core and the shell being prepared by aqueous emulsion polymerization of monomers containing ethylenic unsaturation, the powder comprising:a hydrophobic core consisting of a polymer exhibiting a glass transition temperature of between -30 and 25.degree. C., anda shell, the shell being bonded to the core by covalent bonds resulting from the reaction of an agent for grafting the shell onto the ethylenic unsaturations remaining in the core, wherein the shell is prepared by emulsion polymerization, on the core, of a mixture of monomers comprising:from 50 to 90% by weight of at least one monomer chosen from styrene and a C.sub.1 -C.sub.12 alkyl acrylate or methacrylate,from 15 to 50% by weight of at least one monomer carrying a saccharide group and exhibiting at least one ethylenic unsaturation, andfrom 0.2 to 10% by weight of at least one grafting agent which is an alkene ester or an alkene amide of acrylic or methacrylic acid.