Method for reducing formaldehyde residue of permanent flame retardant pure cotton fabric

The invention relates to the technical field of removing formaldehyde from pure cotton fabric, particularly to a method for reducing the formaldehyde residue of permanent flame retardant pure cotton fabric. The method includes the steps of: (1) washing: performing washing at 70-80DEG C, adding a polyphenol component of a natural Terminalia chebula extract into washing water, adjusting the pH of the washing liquid to 4, conducting washing repeatedly 3-4 times, and then using 90DEG C pure water to perform washing twice; (2) formaldehyde capture agent modification: employing cycloethyleneurea to perform modification treatment on free formaldehyde in the washed fabric for 0.5h 3 times repeatedly; (3) formaldehyde adsorption: using activated alumina, and performing placement in a 40DEG C sealed environment for 48h; and (4) formaldehyde source elimination: adding an oxidant during ammonia fumigating into an ammonia fumigate chamber to oxidize trivalent phosphorus all into pentavalent phosphorus, thus eliminating th