| 摘要 |
This invention includes a process for preparing a solid state polymerized poly(ethylene naphthalate) or PEN polymer comprising: (1) preparing a molten PEN polymer with an intrinsic viscosity of from about 0.25 dl/g to about 0.55 dl/g, (2) dispersing an inert gas into the molten PEN polymer to form a foamed PEN polymer with a void fraction of from about 0.10 to about 0.50, (3) forming the foamed PEN polymer into granules, (4) devolatilizing the granular PEN polymer at a temperature of from about 80 DEG C. to about 140 DEG C., (5) crystallizing the devolatilized PEN polymer at a temperature of from about 150 DEG C. to about 260 DEG C., and (6) solid state polymerizing the crystallized PEN polymer at a temperature of from about 235 DEG C. to about 265 DEG C. to form a solid state polymerized PEN product.
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