Color fixing agent SH-96
Polyamine type color fixing agent is formed by the reaction of diethylenetriamine and dicyandiamide, condensation, deamination and cyclization into imidazoline structure, and then polycondensation to form polymer compound. The measured degree of polymerization is small (n is generally 6-8), which can be dissolved in water.
Color fixing mechanism: (1) polyamine color fixing agent condenses itself to form a film. When immersed in solution, the color fixing agent molecules adhere to the fabric. When the fabric is treated at about 110 ℃, the color fixing agent molecules polycondensate with each other to form a network structure with greater molecular weight, which is attached to the fabric surface to form a layer of film and cover the dye in the film, so as to improve the color fastness; (2) The fixing agent is combined with dyes and fibers. There is – NH2 group at the end of the color fixing agent molecule, and there are also active groups in the cotton fiber macromolecule, such as – oh. Condensation reaction occurs during baking, so that the color fixing agent molecule and the fiber macromolecule are connected by covalent bond. At the same time, there are also active groups in dye molecules, such as – Oh or – NH2. During baking, the dye is covalently bonded with the color fixing agent; (3) Ionic bond binding: polyamine type color fixing agent is cationic. Anionic dyes are generally used in dyeing. Therefore, they can attract positive and negative charges and combine in the form of ionic bond.
Therefore, the color fixing agent can be used as a bridge between the fiber and the dye. Due to the high binding force between the color fixing agent and the fiber and the dye (high covalent bond binding force), and the color fixing agent can form a film on the surface of the fabric and cover the dye in the fiber, the polyamine type color fixing agent can improve the color fastness, and the range is large.
There are many kinds of polyamine color fixing agents in the market. A series of polyamine color fixing agents with good effects have been developed in China, including color fixing agents with reactive groups.
Color fixing agent IFI-841 (indosol F-50)
Cationic resin color fixing agent is called multifunctional reactive color fixing agent. It uses dicyandiamide, diethylenetriamine and hydroxymethyl urea to produce imidazoline. The hydroxymethyl group in the molecule can be used as the reaction group of the color fixing agent and can be cross-linked with the hydroxyl and amino groups in the dye and fiber molecules. Containing imidazoline cationic group, it can combine with anionic dyes or precipitate, so as to improve the color fastness. Because hydroxymethyl is used as the crosslinking group, it contains a certain amount of formaldehyde, which can only be used as a low formaldehyde color fixing agent, not as a formaldehyde free color fixing agent. This kind of fixing agent needs to be baked (180 ℃) after fixing. Because it contains the initial shrinkage of the resin, it can improve the wrinkle resistance, has a large affinity with the fiber, and has a high absorption rate when used in the impregnation method.
The high polymer formed by polycondensation of polyamines can improve the fastness to wet treatment and wet ironing, high color fastness to heat-resistant water and good color fastness to soaping. However, the proportion of dicyandiamide should be well controlled in the synthesis process, because a high proportion of dicyandiamide will cause color change. However, in addition to quaternary ammonium salts, these polymers also have primary amines, secondary amines and tertiary amines, which will produce color change and reduce light fastness after dyeing. Polyamine fixing agents can be used for direct dye fixation and reactive dye fixation.
Color fixing agent IFI-8511
The color fixing agent ifi-8511 is formed by condensation of the initial shrinkage of the color fixing agent ifi-841 with epichlorohydrin, which can further improve the color fastness.
Reactive substances can “bridge” between dyes and fibers to form compounds, and the resin itself can also be crosslinked into macromolecular network structure, so as to form macromolecular compounds with dyes, making the combination of dyes and fibers more firm. Reactive resin color fixing agent has weak cationic property, and the color fixing effect is limited to a certain extent. The reactive resin can be introduced into strong ionic quaternary ammonium salt through quaternization to strengthen its combination with anionic dyes.
The biggest advantage of reactive color fixing agent is that it can improve the wet ironing fastness of reactive dyes, and use the cross-linking reaction of reactive groups to fix the broken and unfixed dyes on the fiber; It can also be crosslinked with hydroxyl and amino groups in fibers and dyes, so as to improve the fastness to wet treatment. Because the aqueous solution of polyamine polycondensation is insoluble in organic oil phase and epichlorohydrin is insoluble in aqueous phase, it is difficult for the molecules of the reaction to collide. If the phase transfer catalyst is added to the reaction system, the above difficulties can be overcome, the reaction speed can be accelerated and the reaction temperature can be reduced.
