Reactive dyes, acid dyes, disperse dyes, cationic dyes, ice dyes and other dyes need water washing and soaping after printing, but it is more difficult than soaping after dyeing, because the soaping bath after printing contains a large amount of polymer slurry. These polymer slurry washed from the cloth is dissolved and mixed with unfixed dyes and printing auxiliaries, which is easy to stain the white ground or pattern of the printed fabric, resulting in a white background The color light of the pattern changes color or the color fastness decreases. Therefore, good white ground anti staining soaps must be used for soaping after printing. According to different printing dyes, fabrics and processes, the white ground anti staining soaps can be divided into reactive dyes printing on cotton, acid dyes printing on silk, wool, disperse dyes printing on polyester / cotton fabrics, ice dyes printing on cotton, cationic dyes printing on acrylic fabrics The white background anti staining soaping agent used after the full width printing of reactive dyes on towel fabrics, the co printing of ice dyes and reactive dyes on cotton fabrics, and the white background anti staining soaping agent used after tie dyeing printing.
Most cotton fabrics (woven and knitted fabrics) are printed with reactive dyes, not only because of their bright color and complete chromatography, but also because of their soft hand feel and good rubbing fastness However, after printing with reactive dyes, if the soap is not properly washed, it is likely to stain the white ground, especially some dark large patterns are easy to stain If kn type reactive dyes or M type reactive dyes are used, it will cause white ground staining [11], mainly because these two reactive dyes contain vinyl sulfone structure, which is easy to break the bond in alkaline medium to form vinyl sulfone group with reaction ability. If vinyl sulfone group is stained on the white ground of unprinted parts, it will react with cotton fiber.
Protein and nylon fiber fabrics are generally printed with acid dyes. When soaping after printing, a large number of unfixed acid dyes and printing paste will stick back to the printed fabric, which will reduce the color fastness of the pattern and stain the white ground without pattern. Therefore, the white ground anti staining soaping agent for acid dyes must be used.
Cationic dyes are generally used in acrylic fabric printing. When soaping after printing, the non fixed cationic dyes are easy to stain the white ground, so the white ground anti stain soaping agent must be used This kind of anti soaping lotion usually uses anionic surfactant, its appearance is dark brown viscous liquid, pH value is 8~10, no foam is used, the fabric after washing is white and white, the flower shape is clear, the color is full and distinct, and it has strong adsorption to cationic dyes.
