Preparation Of Nitrogen Phosphorus Flame Retardant And Its Application In Textiles

Flame retardant is a kind of additive that has the function of inhibiting flame propagation,and can improve the flame retardancy or self-extinguishment of combustible.With the development and implementation of more and more stringent flame retardant standards and environmental protection regulations,and for the sake of safety and environmental protection,halogen-free has become a new trend of flame retardants.Nitrogen phosphorus intumescent flame retardant(N-P IFR)has been widely studied for its halogen-free,environmentally friendly,non-toxic,harmless and other advantages.In this paper,two kinds of N-P IFR which named double trimethylolpropane phosphate ethanolamine salt(IFR1)and double trimethylolpropane phosphate thiourea salt(IFR2)were synthesized with phosphorus oxychloride as the acid source,double trimethylolpropane as carbon source,ethanolamine and thiourea as nitrogen source.The structures of IFR1 and IFR2 were characterized by IR spectrometer,and the results showed that the structures were basically consistent with the expected target products.The thermal stability of IFR1 and IFR2 was investigated by thermogravimetric analyzer,the results show that the initial decomposition temperature(IDT)of IFR1 is 258?,the half decomposition temperature(T50%)of IFR1 is 328?,and the carbon residue of IFR1 at 700? is 15.7%;the IDT of IFR2 is260?,the T50% of IFR2 is 330?,and the carbon residue of IFR2 at 700? is 18.6%.These data show that the two flame retardants have good thermal stability.IFR1 was used for flame retardant finishing of cotton fabric and IFR2 was used for flame retardant finishing of acrylic fabric by the method of dipping-baking,then optimized the finishing process.The flame retardant effect of cotton fabric and acrylic fiber was investigated by vertical combustion test,thermogravimetric(TG)test and cone calorimeter test.The result of vertical combustion test show that cotton fabric have ignition time of 1.25 s,smoldering time of 0s,the damage length of 4.6cm,which can be reach the national standard B1 grade,after finishing by using 250g/L,pH=6.0~7.0 IFR1 solution and baking for 3min at 100?;acrylic fiber have ignitiontime of 2.13 s,smoldering time of 0s,the damage length of 4.8cm,and without melting drop phenomenon,which also can be reach the national standard B1 grade,after finishing by using 200g/L IFR2 solution and baking at 80?for 3 min.The results of TG test show that cotton fabric after finishing by IFR1 solution,its initial decomposition temperature(IDT)decreased by 51?,the maximum thermal weight loss rate decreased by 28%,and the carbon residue of 700? increased by 3.8 times;acrylic fiber after finishing by IFR2 solution,its IDT was reduced by 32?,the maximum thermal weight loss rate decreased by 13%,and the carbon residue of700? increased by 1.3 times.The results of cone calorimeter test show that the addition of IFR1 makes the peak of heat release rate(pHRR)of cotton fabric decreased by 67%,the average of heat release rate(aHRR)of 0~300s decreased by69%,and the total heat release(THR)reduced by 62%;the addition of IFR2 makes the pHRR of acrylic fiber decreased by 48%,the aHRR decreased by 34%,and the THR reduced by 18%.