This document discusses reactive dyes, including their classification, chemical properties, influencing dyeing factors, and application methods. Reactive dyes are classified based on their reactive groups and dyeing temperatures. They form covalent bonds with cellulose and protein fibers during dyeing. Key factors that influence dyeing include pH, temperature, electrolyte concentration, and time. Reactive dyes are applied using discontinuous, continuous, or semi-continuous methods. Their advantages include color permanence due to covalent bonding and easy washing without color transfer. Uneven dyeing can be difficult to strip due to the strong bonds formed.

1. BGMEA University of Fashion
& Technology(BUFT)
Topic: Reactive Dye
Submitted to :
MD. RAIJUL ISLAM
Lecturer, Dept. of Textile
Engineering
Submitted By: Shahadat
Hossain(171-153-0-155)

2. Content
I. Introduction
II. Classification
III. Chemical Properties
IV. Influencing factors
V. Fabric Application Based Dyes
VI. Trade Name
VII. Dyeing mechanism of reactive dye
VIII.Fixation & Hydrolysis
IX. Application method
X. Advantages of the Reactive Dyes
XI. Problem & solution of reactive dye
XII. Conclusion

3. INTRODUCTION
• Fiber reactive dyes are colored organic compounds
that are capable of forming a covalent bond between
reactive groups of the dye molecule and nucleophilic
groups on the polymer chains within the fiber.

4. Why reactive dye is so called?
• Reasons for so named: Reactive dyes are so
called because this is the only type of dye, which
has reactive group, and that reactive group reacts
chemically with fibre polymer molecules and form
covalent bond. ... For this reasons the dyes are so
called. They are also called 'fibre reactive group'.

5. Classification
1) On the basis of reactive group:
a) Halogen (commonly chlorine) derivatives of nitrogen containing heterocycle, like 3
types-
I. Triazine group: procion, cibacron
II. Pyridimine group: reactone Quinoxaline
III.Quinoxaline dyes:levafix
b) Activated vinyl compound:
I. Vinyl sulphone:remazol
II. Vinyl acrylamide:primazine
III.Vinyl sulphonamide: levafix.
2) On the basis of reactivity:
I. Lower reactive dye: Here pH is maintained 12-12.5 by using NaOH in bath.
II. Medium reactive dye: Here pH is maintained 11-12 by using Na2CO3 in dye
bath.
III.Higher reactive dye: here pH is maintained 10-11 by using NaHCO3 in dye bath.

6. Classification
3) On the basis of dyeing temperature:
a) Cold brand:
These types of dyes contain reactive group of high reactivity.
So dyeing can be done in lower temperature i.e. 320-600C.
Ex:PROCION M, LIVAFIX E.
b) Medium brand:
This type of dyes contains reactive groups of moderate reactivity.
So dyeing is done in higher temperature than that of cold brand
dyes i.e. in between 600-710C temperatures.
Example:Remazol, Livafix are medium brand dyes.
c) Hot brand:
This type of dye contains reactive groups of least reactivity.
So high temperature is required for dyeing i.e. 720-930 C
temperature is required for dyeing.
Example : PRICION H, CIBACRON are hot brand dyes

7. I. Alkali Controllable Dye
These are of relatively high reactivity and moderate substantively. They are
applied at relatively low temperature and level dyeing requires controlled
addition of the alkali. Examples include:-
DCT, DFCP and VS reactive dyes
2. Salt Controllable Dye
These dyes are relatively low reactive towards cotton under allcaline conditions
and therefore dyeing temperature will be as high as 80C. Level dyeing requires
carefill addition of salt to promote exhaustion. Examples include:-
TCP, MCT, and MFT reactive dyes
Classification

8. Properties of reactive dye
• During the dyeing process, the reactive group of the dye makes covalent
bond with the fiber.
• These dyes are soluble in water.
• These dyes are normally used for dyeing cellulose and protein fibers.
• All types of shades are available from these dyes.
• The dyeing is done in alkali condition
• Wet fastness is well
• The brightness and rubbing fastness are comparatively well
• The cost of these dyes is cheap
• The dyeing process is very easy.
• This dye reactive group reacts with –OH groups of cellulose and –NH2
group of proteins fiber.

9. Influencing factors:
• Dyeing of cellulosic fiber with reactive dyes is influenced
by some factor. Following factors should consider during
dyeing operation.
1. pH: Reactive dyeing is done in an alkaline conditon for this reason pH of Me
dyeing bath should control. pH should be between 11.5-11.
2.Temperature: Temperature should fix depending on the brand of reactive
dyes.
3. Concentration Tolerance : Concentration of electrolyte depends on the
type of shade.
4. Time: Dyeing time should be between 60 - 90 minutes.
5. Liquor ratio: Huge amount of water is use during dyeing operation. Higher
Me liquor ratio betters the efficiency of dyeing.

10. Fabric Application Based Dyes

11. Trade Name

12. Dyeing mechanism of reactive dye
The dyeing mechanism of material with reactive
dye takes place in 3 stages:-
I. Exhaustion of dye in presence of electrolyte
or (dye absorption).
II. Fixation (under the influence of alkali).
III. Wash-off (unfixed dye from material
surface).

13. Dyeing Mechanism of Reactive Dyes

14. Fixation & Hydrolysis

15. Application method:
These are 3 application procedures available:
1. Discontinuous method-
I. Conventional method
II. Exhaust or constant temperature method
III. High temperature method
IV. Hot critical method.
2. Continuous method-
I. Pad dry method
II. Pad thermofix method
III. Pad-steam method
3. Semi continuous method-
I. Pad jig method
II. Pad batch method.
III. Pad roll method

16. Advantages of the Reactive Dyes
1. Permanency of the colour :
Fibre Reactive Dyes can be easily said to be the most permanent of all
dye types. This is because of an unique quality, unlike other dyes, it can
actually form a covalent bond with the substrate (cellulose or protein
molecule). After the formation of the bond, there is only one
molecule, as the molecule of the is now part of the cellulose fiber
molecule.
2. Easy washing :
The fibres that are dyed with reactive dyes can be safely dyed even
with white garments without the danger of colouring it.
3. Chemical Binding :
The chemical bonds as explained above significantly improves the
product’s colour stability and washability. Thus, no doubt reactive
dyeing of cotton is presently the most popular textile dyeing process in
the world.

17. Problem & solution of reactive dye
• Stripping of reactive dye:
The reactive dye cannot be satisfactory stripped from fibre
due to covalent bond between dye molecule and fibre.
Stripping becomes necessary when uneven dyeing occurs.

18. Conclusion
Reactive dyeing is one of the important ways of dyeing, but usually
in the dyeing process, fabric dyeing liquid through the dip after the
need for intermediate drying, which facilitates subsequent steaming
or baking fixing to improve processing speed and reduce the time
dye hydrolysis, to get high fixation rate and color fastness.

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