| 摘要 |
1,242,023. Crystallising polyester particles. TEIJIN Ltd. 19 Aug, 1968 [23 Aug., 1967; 13 May, 1968 (3)], No. 39640/68. Heading B1G. [Also in Divisions C3 and F4] A process of drying polyester particles comprises (a) heating mechanically stirred non- crystalline polyester particles at 120-200‹C until at least the surfaces of the particles are crystallised, and (b) then drying the particles without mechanical stirring, the particles moving downwardly in a packed state in steps (a) and (b) and being heated in steps (a) and (b) by heated gas moving through the particles. One embodiment of a suitable apparatus for carrying out the process, comprises a column consisting of cylindrical section 7' with inlet 1, cylindrical crystallising section 2 provided with stirrer 3, cylindrical drying section 8 and outlet adaptor 7. The outlet end of section 2 may be flared and perforated. Hot gas is introduced into sections 2 and 8 via inlets 6 and 9 respectively and exhausted via outlet 5. Cylinder 7' is provided with cooling jacket 23 and cylinders 2, 8 may be provided with heating jackets. The upper part of the drying section 8 may be provided with a plurality of rotating rolls 14 having staggered projections 17 for breaking up any fused particles. The section 2 may be substantially above section 8. The hot gas may be air, nitrogen, argon or carbon dioxide. The polyester may be polyethylene terephthalate, a polycarbonate, a polyester prepared from terephthalic acid and 1, 4 cyclohexane diol or a polyester prepared using isophthalic acid, adipic acid, trimethylene glycol, bisphenol A or pentaerythritol. |
