Disperse Dyes

Disperse Dyes

• The term “disperse dye” have been applied to the organic

colouring substances which are free from ionizing groups, are

of low water solubility and are suitable for dyeing

hydrophobic fibres.

• Disperse dyes are the only water insoluble dyes that dye

polyester and acetate fibers. Disperse dye molecules are the

smallest dye molecules among all dyes.

• Disperse dyes are used for dyeing man made cellulose ester

and synthetic fibres specially acetate and polyester fibres and

sometimes nylon and acrylic fibres.

• Carrier or dispersing agents are required for dyeing with

disperse dyes.

• Disperse dyes have fair to good light fastness with rating

about 4-5.

MECHANISM OF DISPERSE DYE

Wander Wall’s Forces.High affinity for Fibers.Attraction between Fiber Surface and the Dye Molecule.

STRUCTURE

SOLUBILITY

Non-Soluble in Water.

CHARGEABILITY

Neutral Charge.Penetrate Because of Transition State of Synthetic Fibers.

ENVIRONMENT BEHAVIOURNon-Environmental Friendly.Human effect dyeing method.

FASTNESS PROPERTIES

Washing : Good .Lightening : Good .Crocking : Good .Gas Fume Fade : Average .

APPLIANCES

They are Applied to Synthetic Fibers such asAcetate, Triacetate, Polyester, Nylon and Acrylic.

COLOUR RANGE

Wide Range of Colors.Bright and Lighter Shades.Major Colors: Pale Yellow and Blue.

COSTCheap method for dyeing process .

Other agents used in Polyester dyeing

Dispersing Agent

• It increases the solubility of the dye in water .

• It helps to increase the rate of the dye exhaustion .

Leveling Agent

• Leveling agents hold the rate of the dyeing and helps to get uniform dyeing.

Buffer

• These agents protect the dye from reduction in high temperature bath .

The Methods Can Be Employed In The Dyeing Of Polyester

High temperature dyeing process .

Thermosol process.

High Temperature Dyeing Process

• High temperature dyeing of polyester can be done in Beam Dyeing machines , Jet dyeing machines and Pressure Jiggers .

• This method dye applied under pressure at temperature of about 130`c .

• Heating help to swell the highly compact polyester polymer and make availablemore space for the dye molecule to enter in to the amorphous region of the fiber .

Dyeing Of Polyester Fabric With Disperse Dyes By High Temperature Exhaust Method

Procedure :

Prepare The Dye Bath Using The Recipe Below

• M:L:R 1:30 to 1:40• Ammonium Sulphate 2g/l• Dispersing Agent 0.5g/l

Dye The Sample Using The Following Dyeing Cycle

Dyeing With Disperse Dye ( High Temperature Exhaust Method )

• First the dye bath is made with the dye , dispersing agent and the temperature is raised to 60`C .

• Next , Formic acid and Ammonium-Sulphate added till the pH is 5-6 .

• The dyeing should be continued and the temperature is raised to 130`C over period of 45 min.

• Then temperature reaches 130`C dyeing is done for 1 hour .

• Rinsed the sample with cold water .

• Removal the disperse dye on the surface of the fabric by using Caustic Soda and Sodium Hydrosulphite and rinsed , Neutralize the sample.

Thermolsol Process

• This process is suitable for mixed fabric of Poly-Cotton or Poly-Wool .

• The thermo-sol dyeing process is consists of the following stages .

Padding Drying

After Treatment

Thermofixing

Padding

The Padding Carried Out At 30 - 40`C With The Following Ingredients

• Dispensing Agent• Water• Disperse dye• Acetic Acid ( pH 6 – 7 )• Wetting Agent• Neutral alginate thickener

Thermosol Process

• After padding the cloth with the dye and the other dried .

• Next stage is fixation of the disperse dye , the cloth is passed through a hot air pin stenter for 60 second at 190 – 210 `C.

• After heat treatment the cloth washed .

Thank You

Ashan Ranasinghe

Gayan Weerasinghe