Abstract: Disclosed is a method for increasing the solid state polymerization (SSP) rates of organic titanate catalyzed polyester. The method comprises in a first step, reacting a dicarboxylic acid or a C1-C4 dicarboxylic diester with a diol at a suitable temperature and pressure to effect esterification or transesterification to prepare a precondensate and in a second step, reacting the precondensate to effect polycondensation at a suitable temperature and pressure to prepare a high molecular weight polyester and in a third step, further increasing the molecular weight and viscosity of the polyester under SSP conditions of a suitable temperature and pressure, where an organic titanate is added in the first step or in the second step as a reaction catalyst, and where a phosphinic acid compound is added in the first step, in the second step or just prior to the third step. The phosphinic acid compound is for example diisooctyl phosphinic acid.