What is the dyeing process in textile:
Table of Contents
Definition:
Dyeing is the process by which the physical and chemical properties of an object change and as a result of this change the dyad is reflected on the object and falls into our eyes as a colored object.
Dyeing is a process by which the physical and chemical properties of an object can be changed. The change in the quality of the object in the dyeing process causes the object to reflect color and show color after reflection.
In other words, dyeing is the physical and chemical process of dyeing the whole product by dipping it in fiber, yarn, or cloth dye solution.
However, in the case of dyeing, textile products are dyed with the help of a dyeing machine with the help of dyestuff and chemicals by controlling certain conditions such as temperature, time, and pH. However, it is important to consider what type of dye should be used for a fiber, what type of dyeing machine is required for yarn or fabric, whether the dyeing work should be done in alkali or acid medium, whether the fabric or yarn should circulate in the dye bath, etc.
What is the dyeing process in textile-Objects of dyeing:
The purposes of dyeing are given below
1) Paint the cloth evenly all over the place with a single color.
2) To enhance the beauty of the fabric externally and make it attractive.
3) In special cases, the whole fabric should be dyed before printing.
4) To attract the attention of the buyers by dyeing with the help of elite colors and to make the fabric exportable.
What is the dyeing process in textile-Theory of dyeing:
Dyeing is the process by which a fiber is immersed in a molecular liquid solution of a colored chemical, i.e., a dye. Therefore, it can be seen that dye molecules enter the fiber from the outside to the inside. Therefore, the density of the dye decreases from the outer side of the fiber. This is called Exhaustion, which reveals the substantivity of the dye.
This substantivity depends on the properties of the fiber and the properties of the dye. This substantivity can be increased by the different gravitational forces between the fiber and the dye. Intermolecular force, Physical force, Hydrogen bond force i.e. H-bond, etc. can be expected in gravity dye and fiber bonding.
The dyeing process for fiber to be colored adheres to the following basic theories, known as the Theory of dyeing.
1. The dye is transferred from the bath to the inside of the surface of the dyed fiber.
2. The fiber absorbs the dye through the outer surface and moves it inwards.
3. Depending on the inner surface of the fiber, the dye spreads from the outer surface to the fiber.
4. The hydrogen bond or any other chemical force or covalent bond binds the dye molecule with the fiber molecule.
All of these theories apply only to water-soluble dyes. But in the case of insoluble dyes in water, the following rules should be followed.
1. The fibers attach to the dye by chemical bonding.
2. This condition is followed by entropy, which breaks down the energy of dyes in the fiber. The above-mentioned theories are described in detail.
The dyeing process is done through four steps. E.g.
A) Absorption
B) Diffusion
C) Migration
D) Anchoring or fixation
A) Dyeing process in textile-Absorption:
From the solution of the dye, the molecules of the dye begin to come to the surface of the fiber and are excreted by the surface of the fiber. This analysis usually depends on the following three factors
1. Electro potential force
2. Temperature & electrolyte
3. Stirring of the solution
1. Electro potential force:
What is the dyeing process in textile? When a textile fiber is introduced into an aqueous solution, it becomes an electrical charge, either positive or negative. If the cellulose fiber is inserted into a neutral solution, it is negatively charged and the protein or polyamide fiber is positively charged.
2. Temperature & electrolyte:
When salt is added to the dye solution, the electrical charge of the fiber is lost, and the temperature accelerates the dye to the surface of the fiber. As a result, the dye easily accumulates on the surface of the fiber.
3. Stirring of the solution:
When the dye solution is stirred, the molecules of the dye cannot get stuck and stick to the surface of the fiber very fast.
B) Diffusion:
Dye molecules enter the fiber from the surface of the fiber, depending on the following factors.
1) Internal surface of the fiber
2) Size of porous and dye molecules
3) Degree of agitation
4) Temperature
5) Fick’s law
1) Internal surface of the fiber:
The interface of cellulose and protein fibers is much larger and has holes in the middle of their long-chain molecules. When the fiber is soaked in the solution, it penetrates through the pores and swells the substance. The higher the interface of the fiber, the better it’s processing.
2) Size of porous and other molecules:
The size of the fiber pore is 30-100 A° and the size of the die molecule is 15-30A° (Angstrom A = 0.1 mu).
3) Degree of agitation:
Depending on the amount of dye, the dispersion of the dye in the fiber depends.
4) Temperature:
As the temperature rises to a certain limit, the speed of the dye molecules increases and the dye molecules enter the fiber.
5) Fick’s law:
Dye molecules move from the surface of the fiber to the center of the fiber according to Fix’s formula. The smaller the dye molecule, the faster it will spread, and if there are more holes in the fine structure of the fiber, the dye molecule will be able to penetrate the fiber more easily.
C) Migration:
Dye molecules are transferred or dispersed all over the fiber. When the temperature rises above 70°C, the speed of the dye molecules will increase and try to penetrate the fiber.
D) Anchoring or fixation:
Dye molecules are stuck or fixed inside the fiber. This is done by hydrogen bonding or co-valiant bonding. In the case of cellulose fibers, the fixation of dye molecules takes place through hydrogen bonds. Hydrogen bonds are formed with the hydrogen group of cellulose fibers. In this way, the dye can be encoded or fixed with the fiber.
When a covalent bond is formed between two carbon molecules, it is very stable. The dye is well stabilized if the co-valiant bond can be increased. A bond is the most permanent bond. If the molecule of the dye is attached to the fiber by a bond, the corresponding dye is more mature. The dye is also well stabilized through salt linkage.
