| 摘要 |
<p>1361080 Solid phase polymerization CIBAGEIGY AG 22 Oct 1971 [23 Oct 1970] 49283/71 Heading C3R A process for the solid phase polycondensation of a thermoplastic polyester comprises maintaining the condensate at a pressure below 1 torr. and at a temperature from 50 to 5‹ C. below its initial melting point in contact with a stream of inert gas fed in at a ratio of less than 2 litres per hour per kilogram of the polymer. The condensate is preferably in the form of particles of uniform size, e.g. 0À5 to 5 mm. in any dimension. Suitable inert gases are nitrogen carbon dioxide, industrial waste gases, helium and argon. The polyester used in the examples is polyethylene terephthalate.</p> |
