Patent ID: 8440766

Claim:
Method for the manufacturing of a multi-stage polymer by the following steps: a) polymerizing monomer mixture (A) comprising a-i) vinyl acetate and a-ii) at least one vinyl ester of an aromatic carboxylic acid via free radical emulsion polymerization to obtain copolymer (A); and b) polymerizing monomer mixture (B) comprising b-i) vinyl acetate and b-ii) at least one vinyl ester of aliphatic branched or unbranched carboxylic acids having at least 3 carbon atoms, via free radical emulsion polymerization in the presence of copolymer (A) to obtain the multi-stage polymer with the proviso that a weight ratio of monomer mixture (A) to monomer mixture (B) ranges from 3:7 to 7:3 and with the proviso that said monomer mixture (B) can also be polymerized first to obtain a copolymer (B) and subsequently monomer mixture (A) is polymerized in the presence copolymer (B) to obtain the multi-stage polymer.