Patent ID: 6852797

Claim:
A process for the preparation of polybutadiene latex, in which butadiene is polymerized by a free radical emulsion polymerization reaction in the presence of initiator and, if required, dispersants and further conventional assistants, wherein the polymerization is carried out in the presence of reactive comonomers in such a way that a beat flow of 43 watt/kg solids content of the polymerization mixture is not exceeded further comprising a heat flow profile with: during a first period of 10-700 minutes, a change in the heat flow per unit time of 0.01-0.5 watt/(kg·min); during a subsequent second period of 0-600 minutes, a change in the heat flow per unit time of −0.1-0.1 watt/(kg·min); during a subsequent third period of 10-1000 min, a change in the heat flow per unit time of <0 watt/(kg·min), wherein the polymerization is carried out by a semi-batch procedure in which (a) in a first stage, a portion of butadiene and at least one portion of reactive comonomer in the form of an aqueous emulsion are initially taken with a thermal polymerization initiator and, if required, dispersants and further conventional assistants and the polymerization is initiated, (b) in a second stage, the remaining amount of butadiene and, if required, the remaining amount of reactive comonomer are added undiluted or in the form of an aqueous emulsion, if required with dispersants and, if required, further conventional assistants, as a feed.