Dyeing Carriers | Some Commercial Name of Dyeing Carriers | Factors Considered For Selecting a Dyeing Carrier | Mechanism of Dyeing Carrier Action

Dyeing Carriers
It has been established that certain hydrocarbons, phenols, amino acids, amides, alcohols, esters, ketones, nitriles etc. accelerate the rate of dyeing polyester fibre with disperse dyes from aqueous medium at temperature up to 100°C. These dyeing assistants alter the dispersing properties of the dyes and the physical characteristics of the fibre so that more dye can be transferred from the dye bath to the fibre. These are called carriers and are necessary for dyeing polyester fibres at the normal pressure and temperature below 100°C to increase the dyeing rate and to permit dye migration within the fibre. Level dyeing of disperse dyes depend on the migration power of the dye which is affected by nature and amount of carrier, dyeing time, temperature and the shade.

Some Commercial Name of Carriers
Commercial Name
Manufacturer
Chemical Class
Solvent OP
Franco
O-phenyl phenol
Tumescal D
ICI
Diphenyl
Palanil Carrier A
BASF
Aromatic Ether
Carrier PDC
TCC
Emulsifiable solvents
Dilatin TCR
Sandoz
Chlorinated aromatic compound
Butyl oleate
HAR
Ester
 
Factors Considered For Selecting a Carrier
  • High carrier efficiency.
  • Availability at low cost.
  • Little or no effect on light fastness of final dyeing.
  • Absence of unpleasant odor.
  • Non toxicity.
  • No degradation or discolouration of fibre.
  • Ease of removal after dyeing.
  • High stability under dyeing conditions.
  • Compatibility with dyestuffs.
  • Ease of dispersion in the dye bath.
  • Low volatility of the carrier including low volatility in the steam.
  • Uniform absorption by the fibre.
Mechanism of Carrier Action
In carrier method of polyester dyeing, carrier is used. Carriers swell the fibre and ultimately cause relaxation. They may operate by opening up the internal fibre structure and allow the dye molecules to diffuse more rapidly. They act as molecular lubricants reducing inter-molecular forces operating in the fibre, thereby following the dye molecule to force its way in. Its action may be described as below:
  • It creates dye film on fibre surface.
  • Carrier takes dye inside the fibre from dye carrier association.
  • It increases the solubility of dye in the dye bath.
  • Carriers penetrate inside the fibre polymer chain and thereby reduce inter-chain attraction. Thus polymer chains become movable and so dye molecules may enter the polymer system of fibre.
  • It increases fibre swelling.
  • The absorbed carrier increases the rate of dye uptake by creating liquid co-fibre.
  • It increases the absorbency power of fibre.
  • It lubricates the thermally agitated fibre molecules.
  • 2-10 gm/lit carrier is used depending on material and liquor ratio and depth of shade.
  • The automatic portion of carrier is postulated to have Van Der Waal’s force and attraction for hydrophobic group of it attracts water.
  • With increasing molecular weight the carrier efficiency also increases up to a certain limit.

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