Abstract: A new phosphorus and nitrogen synergistic flame retardant, 2,4,6three(Osecbutylphenyl phosphinic acyl)1,3,5triazine, was prepared from tricyanogen chloride and Phenyl hypophoaphoeous acid two secbutyl. Each reaction condition was optimized. The optimal reaction condition was as follow: n(tricyanogen chloride):n(phenyl hypophoaphoeous acid dibutyl) was 1：3.2, reaction time was 5 h at 100 ℃ with fractionating the 2chlorobutane generated by the reaction, the target product was obtained after distilling organic solvents and recrystallization with a yield of 89.4 %. The structure of the product was characterized by FTIR, 1H-NMR and the flame retardant properties of the product were measured by limited oxygen index technique. The highest limited oxygen index of the product flame retarded PBT,the product and MCA flame retarded PBT, the product and MPP flame retarded PBT were 21 %, 30 %, 26 %, respectively.

Key words: phosphorusnitrogen synergistic flame retardant, 2, 4, 6-three（O-sec-butylphenyl phosphinic acyl）-1, 3, 5-triazine, synthesis