| 摘要 |
PURPOSE:To obtain a highly polymerized polyester excellent in transparency, hue and thermal properties within a short time, by prepolycondensing a specified terephthalate in the presence of a small amount of a Ge compound or an Sb compound and post-polycondensing the mixture after adding an aromatic sulfonic acid compound. CONSTITUTION:Bis(beta-hydroxyethyl)terephthalte or a composition based on its oligomer is prepolycondensed in the presence of 0.1X10<-4>-1X10<-4>mol, per mol of the acid component constituting the polyester, of a Ge compound and/or an Sb compound to obtain a lowly polymerized polyester of an intrinsic viscosity of 0.2-0.4. After a sulfonic acid compound selected from among compounds of the formula (wherein Ar is an aromatic group, X is OR1, COOR2, or a halogen, m is 1-3, n is 0-3, and R1 and R2 are each H or a lower alkyl) and their acid anhydrides is added in an amount of 1X10<-4>-10X10<-4> equivalent per mol of the acid component constituting the polyester, and the reaction mixture is post-polycondensed.
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