Method for preparing high-tenacity polyester blending type flame retardant

The invention relates to a method for preparing a high-tenacity polyester blending type flame retardant, which comprises steps: aldehydes are added into amine compounds to react for 30-45mins in a dropping mode, and phosphate ester compounds are added in 25-35DEG C, and have a reflux reaction for 5-7h in 40-60DEG C, thereby obtaining the high-tenacity polyester blending type flame retardant. The method for preparing the high-tenacity polyester blending type flame retardant is simple, can be used for commercial process, and has obvious economic and social benefits. The prepared high-tenacity polyester blending type flame retardant is excellent in flame retardant effect, can form excellent compatibility with polyesters, and can not affect high strength of the polyesters basically. The prepared high-tenacity polyester blending type flame retardant is applied to prepare high strength flame retardant polyesters, enables limit oxygen indexes of prepared fabrics to be above 31%, and is low in smoke and does not have poison after having a fire, thereby reducing pollution to environment and damage to human health.