Brief introduction to various dyes(1)
2022-04-28
1. Direct dyes
Structural properties: Direct dyes are a class of water-soluble anionic dyes. Most of the dye molecules contain sulfonic acid groups, and some have carboxyl groups. The dye molecules and cellulose molecules are combined by van der Waals forces and hydrogen bonds.
Dyeing objects and methods: Direct dyes are mainly used for the dyeing of cellulose fibers, but also for the dyeing of silk, paper and leather. During dyeing, the dye is directly dyed on the fiber in the dye solution, and is adsorbed on the fiber through van der Waals force and hydrogen bonding.
2. Acid dyes
Structural properties: Acid dyes are a class of water-soluble anionic dyes. The dye molecules contain acidic groups such as sulfonic acid groups and carboxyl groups, which usually exist in the form of sodium salts. In the acid dye bath, they can be combined with the amino groups in the protein fiber molecules by ionic bonds, so they are called acid dyes.
Dyeing objects and methods: commonly used in silk, wool and polyamide fibers and leather dyeing. Acid dyes dye fibers by their own affinity and bind to fibers with ionic bonds; acid mordant dyes, whose dyeing conditions are similar to those of acid dyes, but require the action of certain metal salts to form chelates on fibers to obtain good results Excellent washing resistance; acid mordant dyes, some acid dyes have chelated metal ions in the molecule, small hydrolysis tendency and good color fastness.
3. Cationic dyes
Structural properties: Cationic dyes are soluble in water and are in a cationic state. The early dye molecules have basic groups such as amino groups, which often exist in the form of acid salts.
Dyeing objects and methods: It is mainly used for the dyeing of polyacrylonitrile fibers. When dyeing, it can be combined with carboxyl anions in protein fiber molecules such as silk in the form of salt bonds.
4. Reactive dyes
Structural properties: Reactive dyes are also called reactive dyes. This type of dye contains reactive groups in its molecular structure, which can be covalently bonded to the hydroxyl and amino groups in the fiber molecule during dyeing to firmly dye the fiber.
Dyeing objects and methods: Reactive dyes are mainly used in the dyeing and printing of cellulose fiber textiles, and can also be used in the dyeing of wool and nylon fibers. The dye dyes the fiber by its own affinity, and then binds firmly to the fiber through covalent bonds under the action of the alkali agent.
Structural properties: Direct dyes are a class of water-soluble anionic dyes. Most of the dye molecules contain sulfonic acid groups, and some have carboxyl groups. The dye molecules and cellulose molecules are combined by van der Waals forces and hydrogen bonds.
Dyeing objects and methods: Direct dyes are mainly used for the dyeing of cellulose fibers, but also for the dyeing of silk, paper and leather. During dyeing, the dye is directly dyed on the fiber in the dye solution, and is adsorbed on the fiber through van der Waals force and hydrogen bonding.
2. Acid dyes
Structural properties: Acid dyes are a class of water-soluble anionic dyes. The dye molecules contain acidic groups such as sulfonic acid groups and carboxyl groups, which usually exist in the form of sodium salts. In the acid dye bath, they can be combined with the amino groups in the protein fiber molecules by ionic bonds, so they are called acid dyes.
Dyeing objects and methods: commonly used in silk, wool and polyamide fibers and leather dyeing. Acid dyes dye fibers by their own affinity and bind to fibers with ionic bonds; acid mordant dyes, whose dyeing conditions are similar to those of acid dyes, but require the action of certain metal salts to form chelates on fibers to obtain good results Excellent washing resistance; acid mordant dyes, some acid dyes have chelated metal ions in the molecule, small hydrolysis tendency and good color fastness.
3. Cationic dyes
Structural properties: Cationic dyes are soluble in water and are in a cationic state. The early dye molecules have basic groups such as amino groups, which often exist in the form of acid salts.
Dyeing objects and methods: It is mainly used for the dyeing of polyacrylonitrile fibers. When dyeing, it can be combined with carboxyl anions in protein fiber molecules such as silk in the form of salt bonds.
4. Reactive dyes
Structural properties: Reactive dyes are also called reactive dyes. This type of dye contains reactive groups in its molecular structure, which can be covalently bonded to the hydroxyl and amino groups in the fiber molecule during dyeing to firmly dye the fiber.
Dyeing objects and methods: Reactive dyes are mainly used in the dyeing and printing of cellulose fiber textiles, and can also be used in the dyeing of wool and nylon fibers. The dye dyes the fiber by its own affinity, and then binds firmly to the fiber through covalent bonds under the action of the alkali agent.
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