How is reactive dyeing done?
How is reactive dyeing done?
Reactive dyes form a new chemical compound when they come into contact with a fiber molecule. Reactive dyes are applied either from a solution with high pH or from neutral solutions that are later alkalized through a separate process. Sometimes different shades are brought out by applying heat to the dyed textile.
What is exhaust method in dyeing?
Batch dyeing (exhaust dyeing) is a method of dyeing a textile material. The method involves the gradual transfer of dye from a dye bath to the textile material in the same piece of equipment. The various methods of batch dyeing result from the type of machine used in the dyeing process.
Why is reactive dyeing process carried out in two steps?
Hydrolysis of reactive dye: This reaction of dye with water is known as hydrolysis of reactive dye. After hydrolysis dye cannot react with fibre. So hydrolysis increases the loss of dyes. This hydrolysis occurs in two stages.
What are the two stage method for reactive dye printing?
What is the Dyeing Method of Reactive Dye?
- Exhaustion.
- Fixation.
- Post dyeing Washing-off process.
Why is it called reactive dye?
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.
Which medium is required for reactive dyeing process?
(a) high PH is required in reactive dyeing because without high PH, Dye will not fixed properly or permanently to the materials. Sodium carbonate is used to maintain PH in case of reactive dyeing.
What is exhaust process?
The exhaust technique is the most common method for application of reactive dyes as it is resistant to small changes of system variables. It comprises two steps: exhaustion and fixation. During exhaustion the dyes are exhausted from the dyebath and come into the fibre phase.
What is reactive dyeing in textile?
Reactive dye: A class of colored synthetic organic chemicals that attach to textile fibers via a chemical reaction that forms a covalent bond. Reactive dyes are the most permanent of all dye types and are the most common type of dye used on cotton and other cellulose fibers.
How many types of reactive dyes are there?
There are primarily two categories: Reactive dyes that react using Nucleophilic substitution reaction. Reactive dyes that react using Nucleophilic addition reaction.
What are the characteristics of reactive dye?
Properties of Reactive Dyes:
- Firstly, reactive dye is anionic in nature.
- Secondly, reactive dye is a water soluble dye.
- Thirdly, they have better wash and light fastness properties.
- After that, they have better substantivity.
- Therefore, they form strong co-valent bond with the cellulosic fiber.
Which group of dye is suitable for exhaust dyeing?
Dichlorotriazinyl reactive dyes are highly reactive, suitable for exhaust method; cellulose dyed with these develop poor wash fastness due to partial hydrolysis of dye, which is very difficult to remove even in repeated washings while monochlorotriazinyl and vinyl sulphone dyes are less reactive, suitable for …
Why reactive dye is so called?
