Anti-staining agents are divided into two types: mechanical and chemical: the former includes wax, grease and some inorganic compounds; the latter includes acids, alkalis, salts, oxidants, reducing agents, etc. There are also special anti-staining agents, such as phenylhydrazine sulfonic acid.
Mechanical resists are substances that prevent dyes from contacting fibers and prevent dyes from fixing on fibers. They can form a film on the surface of the fabric (such as kraft glue, gum, protein, etc.), or can be deposited on the surface of the fabric to retard the dyeing rate of dyes on the fabric, or retard the fixing rate of dyes (such as zinc oxide powder, Insoluble substances such as white powder, calcium carbonate and magnesium oxide), in the subsequent washing process, the ground color dyes in the pattern are washed away together with the mechanical resist to achieve the purpose of resist. In order to make the anti-staining effect good, sometimes a printing paste formulation contains both chemical anti-staining agent and mechanical anti-staining agent.
The function of the chemical resist is to chemically react with the chemicals required for the fixation and color development of the ground dye or the medium necessary for the fixation, and destroy the optimal conditions for the dyeing effect of the ground dye and the fiber. For example, ground color dyes need to develop or fix color in an acidic medium, and alkali or alkaline substances can be used as chemical resists; ground color dyes need to develop or fix color in the presence of oxidizing agents. Can be used as a chemical resist.
Some of these resists are applied to the fiber fabric, so that the dye cannot contact the fiber, such as paraffin, turpentine, starch, clay and barium sulfate. Some of them interact with dyes to make dyes invalid or precipitate, such as lime, lead sulfate, aluminum sulfate, calcium phosphate, etc. There are also anti-staining salt S (the main component of sodium m-nitrobenzene sulfonate) and anti-staining salt H (the main component of ammonium phenylhydrazine sulfonate). It is formulated into a dye-proof paste, first printed on the fabric and then dyed, and the pattern can be obtained after processing.