Patent ID: 6291573
Filing Date: 2001-09-18
Classification: C04B,C08J

Abstract:
A process for preparing a polymer powder from an aqueous polymer dispersion in which the dispersed polymer P comprises in copolymerized form:i) at least one vinylaromatic monomer (a),ii) 1,3-butadiene as monomer (b), and optionallyiii) one or more monomers (c) different than the monomers (a) and (b),wherein said polymer P is obtained by copolymerizing said monomers (a), b) and optionally (c), which comprises drying the aqueous polymer dispersion in the presence of polyvinyl alcohol in an amount of at least 3% by weight, and not more than 20% by weight, of the dispersed polymer P as drying assistant by spray drying, wherein the weight average diameter d.sub.w of the dispersed polymer particles is .ltoreq.2000 nm, to obtain said polymer powder containing said polyvinyl alcohol.