Aim:- Study to dye cotton fabric with Cold brand reactive dyes.
What are 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°.
Aim:- To dye cotton fabric with Hot brand
reactive dyes.
What are 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
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:
- H brand dye powder:- 1 to 2%
- Salt:- 60 g/l
- Soda ash:- 15 g/l
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