The invention provides a
reactive dye salt-free
dyeing method for a cotton fabric by means of
oxygen bleaching, aims to integrate a
desizing-scouring-bleaching process and a cationization modification process, and comprises the steps of
desizing-scouring-bleaching, low-temperature activation
oxygen bleaching, cationic solution dipping,
dyeing and the like. A traditional
oxygen bleaching process and a
hydrogen peroxide-
tetraacetylethylenediamine low-temperature
oxidation process are combined, firstly, the raw cotton fabric is selectively oxidized, selective conversion from hydroxyl to carbonyl on the surface of cotton
fiber is achieved, and meanwhile
desizing, boiling-off and bleaching are conducted on the raw cotton fabric; subsequently, the oxidized carbonyl-containing cotton fabric and a
polyhexamethylene guanidine hydrochloride aqueous solution are subjected to a
Schiff base reaction, and cationic groups are successfully introduced to the surface of the cotton
fiber, so that the dye-
uptake rate and fixation rate of salt-free
dyeing of the
reactive dye are improved, and the modified cotton fabric is endowed with excellent
mechanical strength and whiteness on the basis of the dye-
uptake rate and fixation rate.