| 摘要 |
Dry particles of a polyester of terephthalic acid and a glycol of formula HO(CH2)nOH (where n is 2-10) are obtained by treating moisture-containing amorphous particles of the polyester with hot water or steam whereby to effect at least partial crystallization, and thereafter drying the particles at an elevated temperature; not more than a slight movement between the particles taking place either during the hot water (or steam) treatment or the drying. The process may be effected continuously (a) by passing the particles downwardly through a vertical cylinder into to which steam is blown at the upper portion and hot air at the lower portion, (b) by loading the particles on a moving perforated conveying belt provided in a drying chamber through which, for example, hot air is blown, and spraying hot water on the particles at the beginning of the belt, (c) by feeding the particles on a screw conveyer provided in a housing, a hot gas being blown through the housing in a direction against the movement of the particles and the particles being treated with hot water or steam at the beginning of the conveyer, or (d) by first effecting crystallization on a conveying belt or screw conveyer and then effecting drying in a vertical cylinder. The process may also be effected batchwise, (e) by treating the particles in an electrically-heated vessel with water at 100 DEG C. and then placing the particles in a vertical cylinder through which air at 170 DEG C. is blown from bottom to top, (f) by loading the particles in a vertical cylinder through which first steam at 100 DEG C. and then hot air at 160 DEG C. are blown from bottom to top. Instead of using hot air for the drying, it may be effected under reduced pressure at an elevated temperature. The dried polyester particles may be used for the manufacture of fibres, threads, films or rods. |
