Fixing principle of fixing agent

The current fixing agents can be roughly divided into cationic polymer type fixing agents, resin type fixing agents (containing formaldehyde resin type fixing agents, containing polyamine resin type fixing agents), and crosslinking reaction type fixing agents.

The fixing mechanism of the fixing agent, that is, the fixing agent can improve the color fastness of the aqueous dye on the fiber through: (1) The quaternary ammonium salt or tertiary amine salt in the fixing agent molecule, in an acid medium, depends on a certain strength The cation and the anionic group in the anionic dye structure are ionically bonded to form an insoluble lake to deposit on the inside and outside of the fiber; (2) The reactive cross-linking group on the fixing agent molecule and the active group on the fiber and dye (3) In the drying process of the dyed fabric treated by the fixing agent, the reactive crosslinking groups on the fixing agent molecules cross-link into macromolecules by themselves, forming a layer on the surface of the fabric and fiber A protective film with a certain strength, so as to coat the dye on the fiber, so that the dye is not easy to fall off; (4) The dye-philic structural group on the fixing agent molecule makes a hydrogen bond between the fixing agent and the dye and van der Waals Force binding; (5) The groups contained in the fixing agent molecule, such as imine groups, form coordinate bonds with O, N and other atoms on the dye molecule to form a chelate.

According to the fixing mechanism of the fixing agent, the fixing agent must have a positive charge in the chemical structure, have a reactive crosslinking group, can crosslink by itself, and have a molecular weight large enough to form a protective film during the drying process, and contains Dyes have affinity structural groups, as well as precipitation and complexation of metal ions. In addition, for the formaldehyde-free fixing agent, it is required that no raw materials containing formaldehyde are used in the production, and formaldehyde cannot be generated during the production process and the fixing process, and the dyed fabric after the fixing treatment will not release formaldehyde.