What are the properties of reactive dyes?

Reactive Dyes Properties

  • Reactive dyes come in all shades.
  • Powder, print-paste, and liquid are the different forms.
  • Good Water solubility.
  • Resistant to degradation caused by Ultra Violet rays.
  • Good light and wash fastness.

What is the fastness of reactive dye?

Textile materials coloured with reactive dyes have good wash-fastness; their wash-fastness rating is about four to five. This is attributed to the very stable covalent bond that exists between the dye molecule and the cellulosic fibre.

What is fastness properties of dyes?

Colour fastness is a term—used in the dyeing of textile materials—that characterizes a material’s colour’s resistance to fading or running. Colour fastness is the property of dyes and it is directly proportional to the binding force between photochromic dye and the fiber.

Which dye has fastness properties?

Vat dyes have extremely good fastness properties on cellulose, and are used where fastness to washing and light are paramount, such as for awnings, upholstery, towels and shirting.

Why is reactive dye so called?

The term reactive signifies that the dyes react rapidly with an inert fiber like cotton and produces co-valent bond formation with an excellent color fastness. So, this dye stuff is called reactive dye.

What are the controlling parameters of reactive dye?

Factors to Be Considered During Reactive Dyeing pH – Strong alkaline pH is required ranging from 10.5-11.2. Temperature – Dyeing temperature depends on the brand of dye used. Concentration of electrolyte – The depth of shade is the determining factor of electrolyte concentration. Time – Ranges from 60-90 minutes.

How can you improve fastness properties of reactive dyes?

In all the cases, the use of UV absorbers or antioxidants improves the light fastness of dyed fabrics. The most effective light fastness improvement is found by the application of vitamin C.

What are the factors that influence the performance of reactive dyes?

The higher the dye substantivity, the lower is the migration. The external factors that affect migration are: concentration of the dye, temperature, time, liquor ratio, liquor circulation and the form of textile material.

How is color fastness measured?

The colour fastness following exposure to light of a material is defined as the level of change in colour it undergoes when exposed to light (ISO 105 B02:1994). This is measured using a specimen of the fabric to be tested.

How do you measure color fastness?

Get a white cloth or face washer. Press the wet part of the garment onto the white cloth. If any color comes off onto the white cloth, you know that the item is not colorfast and will run in the wash.

What are reactive dyes?

Reactive dyes are cationic dyes, which are used for dyeing cellulose, protein and polyamide fibres. Reactive dyes are found in power, liquid and print paste form. During dyeing the reactive group of this dye forms covalent bond with fibre polymer and becomes an integral parts of the fibre.

Why is color fastness important?

Importance of Color Fastness: The ability of the fabric to maintain primary color is one of the most important properties of textiles. It is a property of a colorant which allows it to retain its different characteristics despite degradation conditions such as exposure to light and dry cleaning.