Hydrophobic Modification Of Ammonium Polyphosphate And Its Application On Flame-Retardancy Of Polyester Decorative Fabric Of Bullet Train

Given the recent environmental concerns relating to the toxicological characteristics of halogen flame retardants, it has become an inevitable trend in the replacement of antimony-halogen textile backcoating formulations by potentially synergistic halogen-free intumescent flame retardant coating. Such shortcomings of the intumescent flame retardant systems, as poor water resistance and low efficiency of flame retardant performance, have caused the problems of moisture absorption and tackey hand-feel, the exploration of which has become the hotspot in current. This paper explored two techniques:the hydrophobic modification of ammonium polyphosphate (APP-Ⅱ) and the addition of synergistic inorganic metal compounds, which expected to solve the previously mentioned deficiencies of intumescent flame retardant.Firstly, tetraethyl orthosilicate (TEOS) and methyl trimethoxysilane (MS) were selected to hydrolysis and condensate, and produced polysiloxane. Then polysiloxane was used on the hydrophobic modification of APP-Ⅱ. Various impact factors of hydrophobic modification were analyzed, and the optimal conditions were found. With cyclic phosphate and water-based acrylic adhesive latex, modified APP-Ⅱwas used to the flame retardant finishing of suede polyester fabrics. Various impact factors of the effect of flame retardant were analyzed, and the optimal conditions were found.The results show that the optimal conditions for hydrophobic modification are:With ammonia as catalyst, keeping pH value 9-10, the molar ratio of TEOS and MS is 1:5, the amount of water is n (H2O):n (hydrolyzable groups)= 1:2, the sol preparation time is 2.5h, the whole quality of silane monomer is 8% as that of APP-II.The solubility reduced to 0.10 g from 0.49 g, droping about 20.4%; particle size increased form 10.21 um to 12.26 um, increasing about 16.7%; the flame retardant test meeted the United States FAR25.853 burning test standard, and the hand-feel was dry.Secondly, inorganic metal compounds were used as a synergist with the organic and inorganic flame retardants, in order to increase the thermal decomposition sensitivity of phosphorus flame retardants; and they can react with acid compound to reduce moisture absorption and improve the crosslinking degree of coating film. This paper gave priority to aluminum hydroxide(ATH) in use with the IFR system, optimizing its dosage effect on the flame retardant performance and hand-feel. The result proved that zinc oxide, LDHs,4A zeolite and ATH could increase the flame retardent efficiency, Calcium hydroxide and calcium carbonate were contrary to that.8% in use of ATH can low the burning time to 3.6 s, smoldering time to Os,3.4 cm in char length, without melting drop phenomenon, and the hand-feel was good.The flame-retardant mechanism of treated PET fabric was investigated by thermogravimetric(TG), scanning electron microscope(SEM) and energy spectrum analysis(EDS). The results showed that the hydrophobic modification of APP-Ⅱenhanced phosphorus-silicon synergy effect, improving the flame retardance and hand-feel; ATH used as a synergist with IFR could help reduce the phosphate flame-retardant decomposition temperature and enhance the thermal stability of intumescent carbon layer, and hand-feel were also perfect.