| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a polybutylene terephthalate resin high in mechanical strength, reduced in haze and foreign matter, and stably producible with low filtration pressure-rising speed by continuous direct esterification followed by polycondensation. SOLUTION: The polybutylene terephthalate resin is made from a terephthalic acid-based dicarboxylic acid and a 1,4-butanediol-based diol. This polybutylene terephthalate resin is continuously produced by adding a titanium compound as catalyst to multiple reaction vessels. This polybutylene terephthalate resin is characterized in containing substantially neither tin compound nor phosphorus compound and being less than 0.5% in o-chlorophenol insolubles(gelatinization percentage) when heat-treated at 300°C for 2.5 h and in the air, and less than 2.0 kg/cm<SP>2</SP>/h in filtration pressure-rising speed, resulting from assessing filtration property under an extrusion rate of 6.8 g/min at 255-265°C using a 10μm sintered fiber filter with a filtration area of 2.0 cm<SP>2</SP>. COPYRIGHT: (C)2007,JPO&INPIT |
