Submitted By:Kazi Sazed Salman

ID: 111-23-130Hasan Mojumdar Tuhin

ID: 111-23 129

Required Properties of Chemicals for Cotton Fibre &

Fabric Dyeing

Dyeing:Dyeing is the process of coloring fibre, yarn or fabric by using different types of chemicals.

Mostly different types of dyes are used for different dyeing processes.

Cotton DyeingDifferent Types of dyes are used for cotton dyeing.

Reactive DyesVat DyesSulphur DyesAzoic DyesBasic DyesNatural DyesAll Purpose Dyes

Required Properties for Reactive Dye

Must be anionic to attract cellulose Need to have good solubility Must have good light fastness Must have good wash fastness Fixation must be done under alkaline condition Need to have less time requirement This dye is cheap and available

Required Properties of Azoic Dyes

Die will be soluble but final color will be insoluble Have to have excellent light fastness Rub fastness should be increased as much can. Less binding effect should be created by Azo dye Temperature should keep <10 degree Celsius

during dyeing.

Required Properties of Sulphur Dyes

Must produce sulphur linkage with fibre Need to be insoluble in water Reducing agent requirement should be good Must mix with reducing agent properly to be

soluble Dyeing is done under high alkaline condition Shade & wash fastness should be good.

Other chemicals used for dyeing process of cotton:

• Solublizing Agent• Reduction Agent• Alkali• Binding Agent• Wetting Agent• Antifoaming Agent• Anti-migrating Agent• Electrolyte

Requirements of the dye auxelariex

Solublizing AgentIncrease the solubility of dyesControls the sublimation at high temperature

Reduction InhibitorMild oxidizing agent controls the reduction of dyes at high temperature or during steaming.

Binding AgentUse as an adhesive to fix the pigment dyes on cotton fiber at high temperature.

Requirements of the dye auxelariex

Alkali Caustic: Controls the rate of reaction between

dyes and cellulose or in other words it is used for fixation of Reactive Dyes.

Soda Ash:Controls the rate of reaction between dyes

and cellulose or in other words it is used for fixation of Reactive Dyes.Increases the fastness properties during washing

Antifoaming AgentUsed to prevent formation of foam during stirring or during dyeing in one bath.

Anti-migrating AgentIncreases the viscosity of dyeing liquor to protect migration of dyes under high temperature.

ElectrolyteDecreases solubility of dyes in liquorIncreases affinity between dyes and fiber under moist condition

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