Based on the dyeing properties of dyes, dyes can be divided into direct dyes, reactive dyes, vat dyes, sulfur dyes, disperse dyes, cationic dyes and fluorescent dyes.
Direct dyeing
Direct dyes are generally soluble in water because they contain water-soluble groups in their molecular structures. There are also a few dyes that need to add some soda ash to help dissolve. They can directly dye cotton, linen, silk, wool and viscose fibers without relying on other auxiliaries, so they are called direct dyes. Direct dyes have complete chromatogram, bright color, low price, simple dyeing method and uniform color, but their color fastness to washing is poor, and the color fastness to sunlight is not good. In addition to light colors, it is generally necessary to carry out solid color treatment.
Based on the dyeing properties of dyes, dyes can be divided into direct dyes, reactive dyes, vat dyes, sulfur dyes, disperse dyes, cationic dyes and fluorescent dyes.
Direct dyeing
Direct dyes are generally soluble in water because they contain water-soluble groups in their molecular structures. There are also a few dyes that need to add some soda ash to help dissolve. They can directly dye cotton, linen, silk, wool and viscose fibers without relying on other auxiliaries, so they are called direct dyes. Direct dyes have complete chromatogram, bright color, low price, simple dyeing method and uniform color, but their color fastness to washing is poor, and the color fastness to sunlight is not good. In addition to light colors, it is generally necessary to carry out solid color treatment.
Although direct dyes have complete color charts and low prices, most of the banned dyes are direct dyes. Because of the risk of cancer, if the clothes you buy are cheap or have serious color fading, they may be dyed with direct dyes. Buy carefully.
Dyeing with reactive dyes
Reactive dyes are water-soluble dyes containing one or more active groups (also called reactive groups) in their molecules. Under certain conditions, they can interact with hydroxyl groups in cellulose, protein fibers and amino groups and amide groups in nylon. Chemical combination occurs, so reactive dyes are also called reactive dyes. This type of dye is a new type of dye developed in the 1950s. It can be used for dyeing cotton, linen, silk, wool, viscose, nylon, vinylon and other textiles.
Vat dye
Vat dyes (trade name Shilin dyes) are insoluble in water. When dyeing, they must be reduced and dissolved into leuco sodium salts in alkaline reducing solution to dye fibers. After oxidation, they can be converted into original lakes again. fixed on the fibers.
Vat dyes have a complete chromatogram and bright color. They are dyes with excellent properties in all dyes. Especially, the light fastness and washing fastness are inferior to other dyes. The color fastness to rubbing is poor, and some yellow-orange dyes have photosensitive brittleness, so their use is limited.
Sulfur dye dyeing
Sulfur dyes contain sulfur, which cannot be directly dissolved in water, but can be dissolved in sulfide alkali, so it is called sulfur dyes. Sulfur dyes are simple to manufacture, low in price, simple in dyeing process, convenient in color matching, and have good dye fastness, but the color spectrum is incomplete, mainly blue and black, and the color is not bright, which has a brittle effect on fibers.
Acid dye dyeing
Acid dye molecules contain acidic groups such as sulfonic acid groups and hydroxyl groups, which are easily soluble in water and ionized into dye anions in aqueous solutions. Acid dyes have bright color, complete chromatogram, simple dyeing process and easy color matching.
Disperse dyeing
Disperse dyes are a kind of non-ionic dyes with small molecules, simple structure and no water-soluble groups, so they are insoluble in water. When dyeing, the action of dispersing agent is needed to make them uniformly dispersed in the dye in the state of fine particles. In liquid, it is called disperse dye. Disperse dyes have a complete chromatogram, a wide variety, good covering performance, and a wide range of uses, especially for the dyeing of polyester, acetate, nylon, etc. Not easy to fade.
Cationic dye dyeing
Cationic dyes are developed on the basis of the original basic dyes. They are water-soluble dyes with very strong color. They can be ionized in solution to generate pigment cations and simple anions. They are special dyes for acrylic fibers containing acid groups.
Fluorescent dyes
Fluorescent dyes refer to dyes that can emit fluorescence. After absorbing ultraviolet or visible light, they can convert short-wavelength light into longer-wavelength visible light waves and reflect them, showing bright and bright colors. Commonly used in the preparation of fluorescent dye products.
