Patent ID: 6331587
Filing Date: 2001-12-18
Classification: C04B,C08F

Abstract:
A process for the preparation of a dispersion powder from a dispersion having a solids content of at least 45% by weight, which consists essentially of a homopolymer or copolymer of a vinyl ester and is stabilized with a protective colloid consisting essentially of polyvinyl alcohol,said process consisting essentially of polymerizing monomers consisting of the following:a) at least one vinyl ester of a linear or branched monocarboxylic acid monomer having 2 to 12 carbon atoms; andb) optional further monomers which can be copolymerized with said vinyl ester using a polymerization initiator consisting of a water-soluble cationic azo compound,wherein said polymerizing is conducted in the presence of the protective colloid consisting essentially of polyvinyl alcohol and in the complete absence of catonic comonomers, and wherein said polyvinyl alcohol is employed as the protective colloid in an amount of 4 to 15% by weight, based on the total weight of said monomers,and spray drying said dispersion.