Surface active agent
Most of the color fixing agents in the early stage of World War II were treated with copper salt or cationic surfactant. Copper salt has a group combined with copper ion, which can form chelates with direct dyes, reduce the water solubility of dyes, and make the cloth have better soaping fastness and sun fastness. The hydrophilic group in the cationic surfactant has a positive charge and can produce electrostatic adsorption with anions to form a film on the surface of the cloth to fix the color. In addition, it can also form insoluble colored matter with dyes, which improves the washing fastness and sun fastness of the color.
Fixing agent Y and its derivative fixing agent
The most widely used color fixing agent Y (dicyandiamide formaldehyde resin water-soluble initial shrinkage) is formed after condensation of dicyandiamide and formaldehyde, hydrolysis reaction with acetic acid and neutralization with alkaline substances. Its color fixing effect is remarkable. It is usually used as a color fixing agent for cotton and silk dyeing with direct dyes and acid dyes.
Polyamine resin formaldehyde free color fixing agent
In the 1960s, polyamine resin formaldehyde free color fixing agent was most widely used. It is a resin color fixing agent formed by condensation of polyamine with guanidine and its derivatives. It is the first leap in the development of aldehyde free color fixing agent. It has better color fastness to washing compared with color fixing agent y. Among polyamine resin formaldehyde free color fixing agents, color fixing agent sh-96 is a polymer compound formed by polycondensation. Compared with color fixing agent Y, the color fastness is improved by 05-1.
Polycation fixing agent
Polyamine resin color fixing agent contains a large amount of primary amine, which will affect the color light and sun fastness of the fabric, and polycation color fixing agent can overcome this disadvantage. The positive charge in esx-940 of cationic nitrogen-containing polymer reacts with the sulfonic acid group and carboxylic acid group in anionic dye to precipitate the pigment in the cloth and enhance the dyeing effect. Therefore, esx-940 can be used as a substitute for fixing agent y, and the price is low. However, due to the high temperature requirements of esx-940, the temperature needs to be controlled during use.
Reactive fixing agent
Reactive color fixative, also known as cross chain color fixative, appeared in the 1980s. Swiss Sandoz company has developed a color fixing agent called indozol Cr, which not only has ions that can form salt bonds, but also has groups that can react with groups containing active hydrogen, so as to better improve the color fixing effect. By the 1990s, the proportion of resin type color fixing agent in the market gradually reached 70%80%. Resin type color fixing agent has good color fixing effect on most dyes. For example, color fixing agent ed-z is a resin type color fixing agent integrating the functions of salt bond bonding, functional group reaction, molecular film layer protection and metal ion complexation. The color fixing agent contains empty orbital metal ions that can form complexes with dyes with some complexable groups, which improves the sun fastness to a certain extent.
