| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject resin capable of manifesting excellent flame retardancy, drip resistance and having improved hue and hydrolytic resistance by comprising a specific main unit and copolymerizing with a phosphorus compound as a flame retardant. SOLUTION: This flame retardant polyester is obtained by copolymerizing ethylene terephthalate as a main unit with a phosphorus compound including 500-50,000 ppm of phosphorus atom and has a viscosity raising rate 0.006 dl/g.hr under treatment of at 200 deg.C in a high vacuum of 0.05 mmHg for 5 hrs and satisfies formula I [%B.B. is a ratio of cleavage of ester bonding after soaking in pure water at 130 deg.C for 6 hrs and formula II ([η]i is an intrinsic viscosity before soaking; [η]f is an intrinsic viscosity after soaking. Intrinsic viscosity is measured at 30 deg.C, in a mixed solvent comprising phenol/1,1,2,2- tetrachloroethane in the weight ratio of 3/2)]. Useful fibers in various fields are obtained by spinning the resin.
|
