(1) The reason for the poor color fastness of reactive dye printing: The fixation rate of reactive dyes is low, and the fixation rate of domestic K-type reactive dyes is mostly 60%~70%. The unfixed dyes (including hydrolyzed dyes and unreacted dyes) on the fabric must be washed and soaped sufficiently to remove a large amount of floating color, but there are intermolecular forces between the unfixed dyes and cotton fibers, some of which are It remains on the fabric after soaping. At the same time, the covalent bonds between some reactive dyes and cotton fibers are affected by external conditions and are easily broken and hydrolyzed, which is an important factor in poor color fastness.

(3) Effective ways to improve various color fastnesses:

① Increase the frequency of soaping and baking. Reactive dye printing fabric is soaped twice, and pigment printing fabric is dried twice.