| 摘要 |
<p>High mol. wt. polycondensates are prepd. by (1) preparing a precondensate of e.g. poly(ethylene glycol) terephthalate, cooling this precondensate and pulverising it and (2) after drying it by heating, completing the condensation in the solid phase under inert gas, under vacuum or pressure using a fluidised bed at temps. 50 to 5 degrees, pref. 40 to 10 degrees C. below the m.pt. of the polycondensate. This process is characterised by the addn. of pref. 0.01 to 5.0% esp. 0.05 to 5.0% wt. of separating agents. The use of these agents ensures that no agglomeration of the condensate occurs and prevent it fouling the walls of the reactor thus enabling high mol. wt. plycondensates to be prepd. in a short time.</p> |
