Flame-retardant spun-dyed polysete fiber, flame- retardant material comprising the same, and process for producing flame-retardant spun-dyed polyester fiber

A flame retardant spun-dyed polyester fiber obtained by melt-spinning a flame retardant polyester resin composition comprising

• a flame retardant comprising at least one inorganic phosphorus-nitrogen based compound selected from the group consisting of ammonium polyphosphate, melamine polyphosphate and phosphazenes, and inorganic red phosphorus;
• colorant;
• and
• thermoplastic polyester resin;
• wherein the content of said inorganic phosphorus-nitrogen based compound is 0.1 to 8% by mass, the content of said inorganic red phosphorus is 0.1 to 8% by mass, the content of said colorant is 0.01 to 5% by mass, and the content of said thermoplastic polyester resin is 83 to 99.79% by mass, and
• wherein the total of the content of said inorganic phosphorus-nitrogen based compound and said inorganic red phosphorus is 0.2 to 12% by mass based on the total weight of said polyester resin composition.

A flame retardant spun-dyed polyester fiber obtained by melt-spinning a flame retardant polyester resin composition comprising a flame retardant comprising

• an inorganic phosphorus-nitrogen based compound consisting of at least one polyphosphoric acid salt selected from the group consisting of ammonium polyphosphate, melamine polyphosphate, and phosphazenes;
• colorant;
• and
• thermoplastic polyester resin;
• wherein the content of said inorganic phosphorus-nitrogen based compound is 0.1 to 12% by mass, the content of said colorant is 0.01 to 5% by mass, and the content of said thermoplastic polyester resin is 83 to 99.89% by mass, based on the total of said polyester resin composition.