| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for preparing a polytrimethylene terephthalate high in degree of polymerization, low in cyclic dimer content, and excellent in color tone and in thermolysis resistance while retained in the molten condition. <P>SOLUTION: A prepolymer, in which 90 mol% or more is accounted for by trimethylene terephthalate repeating units, is polymerized into a polytrimethylene terephthalate polymer in the presence of a catalyst which is a tin compound lacking direct carbon/tin couplings. The prepolymer is continuously fed into a polymerization reactor, and is ejected, at a temperature not lower than its crystallization/melting temperature and not higher than 280°C, out of pores of a porous board arranged in the polymerization reactor. The prepolymer is then polymerized while falling down along supports under decompression. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
