| abstract |
A polyetherester block copolymer having enhanced compatibility of soft polyether segments with hard polyester segments thereof, excellent mechanical strength, a proper melt fluidity and enhanced resistance to chemicals, heat and light, which copolymer comprises (1) 50 to 95% by weight of polyester segments comprising a dicarboxylic acid component containing at least 50 molar percent of terephthalic acid and a diol component containing at least 50 molar percent of 1,4-butane diol and (2) 5 to 50% by weight of polyether segments comprising poly(tetramethylene oxide)glycol, which is characterized by a large number average molecular weight of from 1,500 to 2,500 and by a small variance of less than 1.70 in molecular weight distribution. |