Dyeing of Cotton Fabric with Reactive Dyes || Cotton Dyeing || Cotton Fabric || Reactive Dyes

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Aim:- Study to dye cotton fabric with Cold brand reactive dyes.

The reactive dyes were invented in 1950s and it has shown a reactive growth. It forms a covalent bond with cotton fiber (cellulosic fiber). The combination of brightness fastness and its application unable this dyes to be use to color the cellulosic fiber

Cold brand reactive brands:

These dyes have two reactive groups therefore called as cold brand reactive dyes i.e. Chlorine.

Application:

Dyeing in the presence of sodium chlorite for exhaustion of the bath. Chemically reacting the dye with the fiber in the presence of an alkali. Example:- sodium carbonate, caustic soda etc. (fixation)

After treatment (soaping and washing) chemical reaction with dyeing.

What is dyeing procedure for cold brand reactive dyes?

1) Preparation of cotton for dyeing:

Bleach material prepared for dyeing must be free from alkali this prevents pre mature localized fixation and improves levelling of the dyes.

2) Preparation of dye solution:

The M brand (cold brand) dye powder is putted with cold water dissolved by adding water at 50°.

Dyeing:

Adjust the dye bath ph to 6.5 – 7 with acetic acid on wing. Suitable liquor ratio for 10 minutes at room temperature. After 15 minutes acid pre dissolved common salt or glaubers salt and dye for another 30 minutes. Add pre dissolved alkali (soda ash) and continue dyeing for 30 min and then drain the dye bath . the salt and the alkali may be added in two portions. Wash the material efficiently after dyeing in cold running water for 10 minutes.

Aim:- To dye cotton fabric with Hot brand reactive dyes.

What are Reactive dyes?

Hot brand reactive brands:-

The application of H brand (hot brand) reactive dyes cotton material is similar to M brand dyeing.

1) Exhaustion Step: The transfer as much of dye onto the fiber as possible.

2) Fixation step: Dye reacts with the fiber forming chemical (covalent) bond in the presence of an alkaline fixing agent like soda ash or mixture of soda ash and caustic soda.

3) After treatment of dyed material i.e. soaping and washing.

What is dyeing procedure for hot brand reactive dyes?

Preparation of goods of dyeing is same as cold brand.

Preparation of dye solution:

Paste the dye powder with cold water and dissolved it by adding water at the temperature of 80°C.

Dyeing Cycle:

Set the dye both at 50°C and ensure the PH is just below 7. Enter the material and run it in the bath for 5 minutes. Now add pre dissolved dyes and continue dyeing for 10 minutes. Add the salt during three portion during the period of raising the temperature to 80 to 85 degrees in 30 minutes. Dye for 20 minutes at 85°C after the last salt addition. Add the alkali for more than 10 minutes. Dye for further 30 to 60 minutes at 85°C depending on the depth of the shade.

Recipe: