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Application of basic dyes on manmade fibers

Application of basic dye on various fibres

Explanation -


(D) Application of basic dyes synthetic mordants : 

The entire process is slow and laborious thanks to the phenol mordanting of cellulose fibres before dyeing and also the mordant treatment following dyeing. 

It's been found that using synthetic mordants, which have an immediate affinity for cellulose, is more convenient than using traditional mordants. 

The artificial mordants are made by heating phenol, sulphur, and a really little amount of iron compound. 

The components of the complexly formulated substances haven't yet been identified. they're going by names like katanol, katonal O, resistance, and tensional BM, among others. 

These mordants even have superior wet fastness than tannin, which is a smaller amount sensitive to residues of iron or other metals. 

In cold water, the mordant is mixed with a bit amount of soda, then the predicament is added until it dissolves. 

betting on the merchandise being employed, the cellulose material to be dyed is next immersed within the solution for one to 2 hours at 60 to 90°C. 

Tannionol BM's manufacturers advise adding 20% common salt to assist with tiredness. 

After that, the material is rinsed and dyed with the chosen basic colours at temperatures between 35 and 45 °C.

(E) Application of basic dyes to acrylic fibre:

The majority of acrylic fibres available today have compact structures that can be coloured using dispersion dyes. 

Depending on the type of dye sites inserted into the fibre during copolymerization, basic dyes may be employed. 

(a) Mechanism of dyeing : 

Steps -
(1) Diffusion of dye to the outer surface 
(2) Adsorption of dye
(3) Diffusion of dye from the surface
(4) Ion exchange


  • First step - Diffusion of the ionised dye through the electrical double layer surrounding the fibre.
  • Second step - Adsorption of dye cations at the dye sites on the fibre surface gradually neutralising & finally reversing the zeta potential of the fibre.
  • Third step - Diffusion of the dye from the surface of the fibre into the interior, especially at temperatures above the second-order transition of the fibre.
  • Fourth step - Ion exchange with the dye sites inside the fibre. 

(b) Retarding used in acrylic dyeing : 

Various approaches have been explored to solve the problem of uneven dyeing of acrylic fibre. 

These include the use of the following -

(i) A Cationic Retarders 
(ii) An Anionic Retarders 
(iii) A Polymeric Retarders 
(iv) The Defitherm process 

Explanation - 

(i) Cationic Retarders

(ii) Anionic Retarders

An anionic or cationic substance is added to the dye bath to make a cationic, which is utilised in acrylic dyeing. 

A cationic product's cations compete with the dye's cations for the anionic dye sites within the fibre when it's employed, lowering the number of dyes that may actually be found within the dye bath

Although it must be kept in mind that if too many retarders are employed, there is also a difficulty with the build-up of shade, a number of the bound cations of the retarder detach from the fibre at a later stage of dyeing, especially at higher temperatures. 

This levelling technique should only be used when the dye generates incredibly uneven hues. 

As a result, the cationic retarding agents work to produce level dyeing outcomes.

As retarding agents in acrylic dyeing, anionic auxiliaries also are useful. 

These auxiliaries' anions combine with the dye cations to come up with complexes that are electrically neutral. it's necessary to supply these compounds in a very finely distributed form. 

When a fibre is dyed, the complex is adsorbed on its surface, from which it diffuses into the fibre's composition. 

The complexes mechanically disperse into the fibre because they contain an electrical charge and lack attraction for the fibre. 

Raising the dyeing temperature causes the complexes to disintegrate into anionic retarder molecules, levelling the fibre structure.

Application -
The dye bath is heated to 60°C using the recipe listed below. The cationic dye is introduced after the items have run for 10 minutes. In 30 minutes, the temperature is gradually increased to the boiling point, when dyeing is carried out for 60 to 90 minutes. The material is then cleaned, soaped, and dried as usual once the dye bath has gently cooled and been dropped.

Application : 

The dye bath is preheated to 60°C according to the recipe below. Before adding the dye solution, the material is run for a brief period of time to verify that the dye bath is uniformly heated. Rapidly raising the temperature to 80°C, it is then brought to a boil and held there for 60 to 90 minutes. Final washing, drying, and soaping of the goods


(1)  Sodium acetate=0.5 gpl

(2)  Acetic acid = 0.5 gpl

(3)  Cationic Retarders=0.5%
(4) Temperature=60-100°C 

(5) Time = 60 - 90 minutes

Recipe -
(1) Anionic Retarders =0.5 - 2%
(2) Non-ionic dispersing agents= 2 to 3% 

(3)  Acetic acid=0.5 %

(4)  Sodium acetate=0.5%

(5) Temperature=80-100°C

(6)  Time= 60 to 90 minutes


(iii) Polymeric cationic Retarders (PCR) : 

Compared to other cationic retarders, these are cationic poly-quaternary ammonium compounds with high molecular weights (10000–20,000). (300-500). due to their size, the polymeric retarders cannot penetrate the fibre and must be the fibre's surface. 

These retarders have an affinity for the surface of the fibre because they need numerous charges along the chain. 

Therefore, even at concentrations as low as 0.1 to 0.2 percent, these retarders effectively regulate the speed of dyeing. 

(iv) Defitherm process : 

This method was created to evenly dye acrylic fibres with simple colours. 

With this method, there's no concern about temperature variations and therefore the ensuing uneven dyeing because the fibres are dyed continuously at a collection temperature. 

The discrepancies caused by the concentration of the dyestuff are eliminated by adding the dye within the most concentrated form feasible at the recommended dyeing temperature. 

The temperature at which the fabric is coloured depends on how quickly the dye bath exhausts. 

The dye bath also contains Defithermal TR, a quaternary ammonium chemical that is a thermo-regulator and retardant. Additionally, it wears down the fibres. 

This product must only be added if dyeing at a calculated, precise temperature, like T=70, which is the temperature at which the tub exhausts after 70 minutes, is impossible for a few reasons. 

With Defithermal TR, the dyeing temperature could also be increased, allowing the dye bath to be exhausted in only 70 minutes while still dyeing the fibre at greater temperatures. 

Methylene blue - basic dye
Methylene blue - basic dye

About basic dye
About basic dye

Questions -

  1. Describe the application of basic dyes on various fibres.
  2. Explain the application of basic dyes on synthetic mordants fibre.
  3. Explain the application of basic dyes on acrylic fibre.


About Basic Dyes. (n.d.). from

Basic Dyes. (n.d.). from

Basic dyes in textile. (2021, January 21). Leartex; Leartex Magazine.

Hasin, S. (2021, February 4). Clear your doubts with Basic dye!! Textile Property.

Patwary, E. M. Z. (2012, May 3). What is basic dyes. Textile Fashion Study; Engr. Mohammad Zillane Patwary.

textileblog. (2021, September 8). What is Basic or Cationic Dye. Textile Blog.

(N.d.). from

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Writer - Rushikesh Patil (Textile Engineer)
(DKTE Society textile engineering college ichalkaranji)
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