Polyurethane latent catalysts obtained by emulsion solvent evaporation

Many efforts have been made to develop catalysts for polyurethanes (PUs) due to their significant roles in the manufacturing process. However, it is still a long-standing technical issue to manipulate the catalytic activity and enhance the storage stability of PU precursors by using suitable catalyst. In this work, a new microcapsule thermolatent catalyst was prepared by emulsion solvent evaporation (ESE) method with a dibutyltin dilaurate (DBTDL) core and a polymeric shell. The glass transition temperature ( T g ) of polymeric shell was utilized as threshold temperature. By changing the composition of acrylate copolymers, the glass transition temperature of polymeric shell could be controlled, which further moderated the latency and catalytic activity of ESE microcapsule catalysts. Compared to DBTDL, all ESE microcapsule catalysts showed certain latency at 30 °C. The catalytic activity of ESE microcapsules was rapidly increased at 70 °C. In the ESE microcapsule catalysts, ESE1 sample exhibited excellent performance due to the suitable T g and uniform morphology. Compared to phenyl mercury neodecanoate and DBU, which are traditional thermolatent catalysts, ESE1 sample showed more excellent latency and catalytic activity.