| abstract |
A method of increasing the rate of metal-catalyzed solid state polymerization (SSP) of polyesters is disclosed. The method comprises: in a first step, reacting a dibasic carboxylic acid or a C 1 -C 4 diester of a dibasic carboxylic acid with a diol at an appropriate temperature and pressure for esterification or transesterification to prepare a precondensate, And in the second step, the precondensate is reacted at an appropriate temperature and pressure for polycondensation to prepare a high molecular weight polyester, and in the third step, the polycondensate is further increased under the SSP condition of an appropriate temperature and pressure. Molecular weight and viscosity of esters where a metal catalyst is added as a reaction catalyst in the first or second step, and where a certain phosphinic acid compound is added in the first step, in the second step, or just before the third step . The polyester product exhibits low aldehyde formation during the melt processing step and excellent color. |