The invention discloses a preparation method of a double-layer shading fabric, and relates to the technical field of textiles. According to the invention, dibenzyl phosphite reacts with
ethambutol, benzyl is introduced, a P-N bond is formed,
thermal stability and
oxidation resistance are improved, phosphite is introduced, surface resistance of the material is reduced, a
decomposition reaction is carried out during
combustion to generate a non-combustible product, a
nitrogen element is assisted, a porous foamy
carbon layer is generated,
oxygen is isolated from entering, and antistatic and
flame-retardant effects are realized; the modified
flame retardant prepared by matching tetraphenyl
silicate and tetrachlorobisphenol A contains more
chlorine elements, interrupts a
combustion chain reaction, forms a
flame-retardant carbonized layer, assists phenyl
silicate, improves the
thermal stability and improves the
ignition point, so that the flame-retardant performance of the
polyester is improved, and the flame-retardant performance of the
polyester is improved. A glassy covering layer can be formed on the surface of the material during
combustion, and is matched with a
carbonization layer to jointly isolate
oxygen and combustible materials, so that flame spreading is quickly inhibited, and the flame-retardant effect is further enhanced.