| abstract |
Polybutylene terephthalate has an intrinsic viscosity of 0.7 to 1.0 dL/g and an end carboxyl group concentration of 0.1 to 18 μeq/g, which is produced in a presence of a catalyst comprising a titanium compound and a metal compound containing a metal of Group 2A of the Periodic Table. In the preferable embodiment of the present invention, the polybutylene terephthalate has a crystallization temperature of 170 to 195° C. as measured at a temperature drop rate of 20° C./min using a differential scanning calorimeter, an end vinyl group concentration of not more than 10 μeq/g, and not more than 10% of a solution haze of a solution prepared by dissolving 2.7 g of said polybutylene terephthalate in 20 mL of a mixed solvent containing phenol and tetrachloroethane at a weight ratio of 3:2. n The polybutylene terephthalate of the present invention exhibits excellent color tone, hydrolysis resistance, heat stability, transparency and moldability as well as a less content of impurities, which is suitably applicable to films, monofilaments, fibers, electric and electronic parts, automobile parts, etc. |