| 摘要 |
<p>A continuous process for the production of poly(trimethylene terephthalate) is disclosed. According to the process, a liquid feed mixture comprising bis 3 hydroxypropyl terephthalate and or low molecular weight polyesters of 1,3 propanediol and terephthalic acid, the liquid feed mixture having a mole ratio of propylene groups to terephthalate groups of 1.1 to 2.2 is fed to a prepolymerizer. Bis 3 hydroxypropyl terephthalate and the low molecular weight polyesters are continuously polymerized to form a poly(trimethylene terephthalate) prepolymer and a first stream of gaseous by products. Poly(trimethylene terephthalate) prepolymer having a relative viscosity of at least about 5 is continuously withdrawn from the prepolymerizer and continuously fed to a final polymerizer, where it is continuously polymerized to form a higher molecular weight poly(trimethylene terephthalate) and a second stream of gaseous by products. Higher molecular weight poly(trimethylene terephthalate) having a relative viscosity of at least about 17 is continuously withdrawn from the final polymerizer.</p> |
