Difference between Reactive and Vat Dyes

Topic

Reactive dye

Vat dye

MECHANISM

Covalent Bond Formation.


Good Affinity for the Cellulosic Fibers.


Smaller Molecule Size.

Vatting Process:

 {Converting Water-Insoluble pigment into a Water-Soluble dye}.

Redox Reaction occurs

Reducing agent HYDROSE provides the attraction for the fibers. Again the dye is converted into the insoluble form inside the fiber

STRUCTURE

SOLUBILITY

Easily Soluble in Water.

Good Affinity for Water.

Polar Nature.

In-Soluble in Water.

Adding Reducing Agents to become Soluble.

 

CHARGEABILITY

Negatively Charged.

Remove Negative  Charge by Adding Salts,

i.e. NaCl

Negatively Charged.

Alkali is Used for Removing Charge.

 

SUBSTANTIVITY

Good Substantivity for the Fibers.

High Degree of Fixation Efficiency.

pH Range: 7 - 11

Substantivity is good for Cellulosic Fibers.

High Fixation because of Reducing Agents.

pH Range :  12 - 15

FASTNESS PROPERTIES

Washing    : Good   

Rubbing  : Moderate

Lightening   : Good

Chemical  :  Stable

Perspiration: Good

Washing        :  good

Lightening      :  Good

Crocking         : Poor

Chemicals       : Average

Perspiration   : Good

APPLIANCES

They are Applied to Cellulosic, Protein and Polyamide Fibers;

 i.e. Cotton, Wool.

They are Applied to Cellulosic and Protein Fibers; i.e. Viscose Rayon, Wool.

COLOUR RANGE

Wide Range of Colors.

Brighter Shades.

All Colors are Achievable.

Large Range of Colors.

Dark Shades Available.

Major Colors: Indigo, Green and Black. 

ENVIRONMENT BEHAVIOUR

Non-Environmental Friendly.

Carcinogenic Dye.

Non-Environmental Friendly.

Cancer Causing Dye

COST

U.S: 0.5 - 1.8 $/Kg.  

Cheap

U.S: 9.9 – 13.98 $/Kg

Average     

 

EASE OF PROCESS

Easy

Difficult

POPULARITY

Widely used for dyeing garments i.e. Ladies wear, Men’s wear, Kid’s wear

Widely used in dyeing jeans or denims

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