Surfactants are an important class of chemical materials with unique structures and properties. They are widely used in daily life and industrial production. Degreasing agents, immersion additives, levelling agents and other chemicals used in fur processing all contain surface activity.
The surface active agent that can play the role of leveling is called leveling agent or dyeing auxiliary. The surface active agent as a dyeing auxiliary has the following functions during dyeing:
①Improve the wetting and permeability of the dye liquor to the fiber, and make the insoluble dyes such as disperse dyes evenly melt and disperse;
② Control the dye molecules to slowly contact with the dyed object to slow dyeing;
③ Transfer the dye in the dark part to the light part, i.e. transfer dye;
In the dyeing process, the application of surfactant surface activity is mainly to improve the wetting and permeability of the dye liquor to the fiber, and other properties are the application of derivative properties. When dyeing with poorly soluble dyes, only a small amount of dyes are dissolved in water in molecular form, and more dyes are encapsulated or absorbed in micelles formed by surfactants. There is a dynamic equilibrium between the dye molecules distributed in the solution in a molecular state and the dye molecules in the micelle. The dye molecules dissolved in water during dyeing are adsorbed by the fiber and gradually diffuse into the fiber, and the balance of the dyeing system will move accordingly. The micelle formed by the surfactant during the entire dyeing process is like a small dye warehouse. Continuously transport dye molecules into the dye bath at a moderate speed.
The leveling agent has a fiber-friendly type, a dye-friendly type, and both are type-friendly. The fibrophilic level dyeing agent acts as a leuco dye, competing with the dye molecule for the coloring position on the fiber at the initial stage of dyeing. Because the leveling agent has small molecules and fast penetration, it penetrates into the fiber first and occupies the dye position on the fiber, while the dye molecule is large, although the movement speed is slower, but it has greater affinity to the fiber, so the dye molecule can finally The levelling agent molecules attached to the fibers are gradually replaced. This process delays the dyeing time, so as to achieve the purpose of slow and level dyeing. Dye-philic leveling agents have a greater affinity for dye molecules. After the leveling agent is added to the dye bath, the dye molecules are attracted by the leveling agent molecules. The dye molecules are not easy to approach the fiber, which delays the dyeing speed. For the purpose of levelling. Also due to the strong attraction of the leveling agent to the dye molecules, the dye in the dense part can be pulled back into the dyeing bath, and then dyed in the light part to achieve the purpose of dye migration.
Fixing is to prevent and reduce color fading. The surface active agent with fixing effect is called fixing agent. The fixing principle of the fixing agent is to use the oppositely charged substance with the dye to form an insoluble precipitate, that is, co-precipitation, to fix the dye on the dyed object, so as to achieve the purpose of fixing.
Through the analysis of the action mechanism of the salt and the active agent dyeing auxiliaries, they are all used in the dye bath to neutralize the dye or fiber to achieve the effect of slow dyeing, migration or promotion, and improve the uniformity of dyeing The degree and fullness can increase the absorption rate of the dye and increase the fastness of dyeing.
In the early dyeing process, people have always used salt dyeing auxiliaries. It was not until the 1930s that surfactants became an industry, and later were they used as dyeing auxiliaries in the textile industry, and were then cited In the fur dyeing industry, dyeing auxiliaries have undergone revolutionary changes.
In the application, people have found that surfactant dyeing auxiliaries can completely replace salt dyeing auxiliaries, and the effect is much better. With the continuous research and development of fur-specific chemical material manufacturers, functional surfactant dyeing auxiliaries continue to emerge. On the basis of leveling, they are given new functions such as deepening the fur and making the skin board. The appearance of new materials has improved the dyeing quality of fur. Coupled with the well-known reasons that salt can cause water pollution, in recent years, salt dyeing auxiliaries have gradually withdrawn from the stage of fur dyeing.