| 摘要 |
<p>The invention relates to a continuous process for the preparation of segmented elastomer polyester copolymers that shows greater flexibility with respect to the types and amounts of product to be produced than the known processes. The flexibility is achieved by splitting up a low-molecular PBT product stream from a continuous PBT process and partly using it as feed for the transesterification reaction with the polyalkyleneoxide glycol yielding soft segments to form a low-molecular segmented polyester copolymer, which is subsequently further condensed in the melt or optionally in the solid phase to form high-molecular segmented polyester copolymers. Even greater flexibility can be obtained by operating several parallel production lines for segmented polyester copolymer. Fluctuations in the types of copolyester product to be produced and the amounts thereof are accomodated predominantly in the polycondensation step of the PBT production.</p> |
