Cationic fixatives are commonly used in nylon dyeing because they form an electrostatic attraction with negatively charged dye molecules, thereby increasing color fastness and affinity between the dye and the fiber. Here are some examples of cationic fixatives for nylon:
Silvafix 5 and Silvafix NH
These brown, water-soluble fixatives improve wet fastness without affecting hand feel. They can also be used as retention agents in cotton/nylon blend dyeing.
DYMAFIX DM-2533
This water-soluble cationic polymer improves color fastness to washing, saliva, perspiration and water stains. Especially suitable for black nylon cotton fabric and red cotton fabric.
Nylofix-993
This low-dust, powder fixative is stable in acidic conditions and improves wet fastness performance. It can also be used as a leveling agent for nylon/wool blends and a retaining agent for nylon/cotton blends.
Working mechanism of color fixing agent
Dyes are dyed on different fibers, and their dyeing mechanisms and color fastnesses are different. Therefore, the mechanism of fixing agents and the application of fixing agents are also different.
1. Use the quaternary ammonium salt or tertiary amine salt in the fixing agent molecule to combine with the anionic group in the ionic dye structure, so that the dye and the fixing agent form an insoluble color block and settle on the fiber, thereby improving the color dye on the fabric. Fastness.
2. Use the reactive groups in the fixative molecule to cross-link with the reactive groups on the dye molecules and the hydroxyl groups on the cellulose molecules to reduce the water solubility of the dye.
3. Utilize the film-forming properties of the color-fixing agent on the fabric to improve its color fastness. During the high-temperature drying process of the color-fixing agent, the reactive cross-linking groups on the color-fixing agent molecules cross-link themselves into macromolecules, forming a protective film with a certain strength on the surface of the color-fixing agent. Fabrics and fibers, wrapped with dyes. Coated on fibers to prevent dye from falling off easily.
Types of color-fixing agents
According to the dye fixation mechanism, fixing agents can be divided into two categories: reactive fixing agents and non-reactive fixing agents.
1. Reactive color-fixing agent refers to the introduction of reactive groups into the color-fixing agent molecules, and epoxy groups are commonly used. This type of fixative can form covalent bonds with certain groups in fiber dye molecules, which is more conducive to improving dye fastness.
2. Non-reactive fixatives refer to two types of film-forming and blocked water-soluble groups on the fiber surface. The main types are cationic fixatives and resin fixatives.
