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The Nature Of Reactive Dyes

Mar. 09, 2021
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The Nature Of Reactive Dyes

All types of shades can be obtained from these dyes.

Reactive dyes exist in powders, liquids and printing pastes.

Reactive dyes are soluble in water.

They are very light fast and have a rating of 6. The dye has a very stable electronic arrangement, which can protect the degradation of ultraviolet rays.

Textile materials dyed with reactive dyes have good washing fastness, with a grade of 4-5. This is due to the formation of strong covalent bonds between the fiber polymer and the reactive groups of the dye.

Reactive dyes have brighter hue and moderate rubbing fastness.

Reactive dyes have good fastness to perspiration, with a grade of 4-5.

Factors to consider when reactive dyeing

pH-Strong alkaline requires a pH range of 10.5-11.2.

Temperature-The dyeing temperature depends on the brand of dye used.

Electrolyte concentration-shading depth is a factor that determines the electrolyte concentration.

Time-the value range is 60 minutes to 90 minutes.

The higher the liquor-liquid ratio-the higher the liquor-liquid ratio, the higher the efficiency.

Dissolution of reactive dyes

Due to the covalent bond between the dye molecule and the fiber, the reactive dye cannot be stripped from the fiber well. When the dyeing is uneven, decolorization is necessary.

Partial peeling of reactive dyes

Treatment of dyed fabrics with dilute acetic acid or formic acid can result in partial decolorization. The temperature here is increased to 70-100°C. The amount of acid used is as follows:

Glacial acetic acid: 5-10 parts

Add water: 1000 parts


Formic acid: 2.5 ~ 10 parts

Add water: 1000 parts

Temperature: 70-100°C

Time: until the desired shadow is obtained.

Advantages of reactive dyeing

Smart, bright colors

Color persistence

Covalently fixed. High washing fastness (WF)

Various temperatures, including low energy (cold dyeing)

Disadvantages of reactive dyeing

Incomplete fixation (hydrolysis problem)

Washing needs (suitable for high WF)

Need high concentration of salt

The color is not easy to remove in the wastewater treatment process, and in many cases, the dye is not easy to biodegrade

Precautions for Reactive dyeing

Hot water should not be used for highly reactive dyes because of the possibility of hydrolysis.

Due to the hydrolysis of the dye, the prepared dye solution cannot be stored for later use.

When making printing paste, low-reactivity dyes are used.

It is dangerous to inhale the dust of reactive dyes, so a protective mask is needed.

Most reactive dyes have a certain shelf life.

Why did reactive dyes develop?

The main reason for the discovery of reactive dyes is the poor washability of direct dyes. In addition, the dyeing process of sulfur dyes and vat dyes on cotton is very complicated.

Are reactive dyes not fading?

They show good to excellent fastness in different wet treatments, but the incomplete removal of unreacted and hydrolyzed dyes results in poor washing fastness. Light fastness is moderate to good. The fastness to peroxide and chlorine bleaching is also moderate.

We are Reactive Dyes Suppliers. If you are interested in our products, please feel free to contact us.

Hydro Peroxide Stabilizer LH-P1510