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DYING & PRINTING

SESSION 9

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Dyeingreaction with fiber moleculestime is required

Printingpigments, bonding substance

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Dye

Organic compound that is water or other

carrier soluble, has affinity for fiber (forms

some kind of bond with fiber).

Pigment

Insoluble inorganic compound glued or

bonded onto fiber surface; no affinity for fiber

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Methods of Dying

Batch

Continuous

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Types of Dyeing

Acid dye

Basic dye

Direct dye Vat dye

Reactive

Disperse Sulfur

Azo

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Acid (anionic): Wool, silk, nylon; some rayon, acrylic,and polyester; bright colors, poor wet fastness and mayhave poor light fastness.

An acid dye is a dye, chemically a sodium (less oftenammonium)

salt of a sulfuric, carboxylic or phenol organic acid

http://en.wikipedia.org/wiki/Dyehttp://en.wikipedia.org/wiki/Dye

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Cationic (basic): Acrylic, wool; some polyester andnylon; good fastness on synthetics, but poor on naturalfibers; bright colors.

Basic dyes are water-soluble cationic dyes that are

mainly applied to acrylic fibers, but find some use forwool and silk. Usually acetic acid is added to the dyebath

to help the uptake of the dye onto the fiber

http://en.wikipedia.org/wiki/Cationichttp://en.wikipedia.org/wiki/Acrylic_fiberhttp://en.wikipedia.org/wiki/Acetic_acidhttp://en.wikipedia.org/wiki/Acetic_acidhttp://en.wikipedia.org/wiki/Acrylic_fiberhttp://en.wikipedia.org/wiki/Cationic

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Direct: Cellulosic fibers; similar to above, but brighter

colors; large, planar molecules; moderate wet fastness;

most commercially important class at present

Direct orsubstantive dyeing is normally carried out in

a neutral or slightly alkaline dyebath, at or nearboiling

point, with the addition of eithersodium chloride (NaCl)

orsodium sulfate (Na2SO4) orsodium

carbonate (Na2CO3).

http://en.wikipedia.org/wiki/Substantive_dyehttp://en.wikipedia.org/wiki/Alkalinehttp://en.wikipedia.org/wiki/Boiling_pointhttp://en.wikipedia.org/wiki/Boiling_pointhttp://en.wikipedia.org/wiki/Sodium_chloridehttp://en.wikipedia.org/wiki/Sodium_sulfatehttp://en.wikipedia.org/wiki/Sodium_carbonatehttp://en.wikipedia.org/wiki/Sodium_carbonatehttp://en.wikipedia.org/wiki/Sodium_carbonatehttp://en.wikipedia.org/wiki/Sodium_carbonatehttp://en.wikipedia.org/wiki/Sodium_sulfatehttp://en.wikipedia.org/wiki/Sodium_chloridehttp://en.wikipedia.org/wiki/Boiling_pointhttp://en.wikipedia.org/wiki/Boiling_pointhttp://en.wikipedia.org/wiki/Alkalinehttp://en.wikipedia.org/wiki/Substantive_dye

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Disperse: originally developed for the dyeingofcellulose acetate, and are water insoluble. The dyes

are finely ground in the presence of a dispersing agent

and sold as a paste, or spray-dried and sold as a powder

http://en.wikipedia.org/wiki/Cellulose_acetatehttp://en.wikipedia.org/wiki/Cellulose_acetate

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Reactive: Natural fibers; bright, pure colors; good toexcellent fastness.

Reactive dyes utilize a chromophore attached to

a substituent that is capable of directly reacting with the

fibre substrate. The covalent bonds that attach reactive

dye to natural fibers make them among the most

permanent of dyes.

http://en.wikipedia.org/wiki/Reactive_dyeshttp://en.wikipedia.org/wiki/Chromophorehttp://en.wikipedia.org/wiki/Substituenthttp://en.wikipedia.org/wiki/Chemical_reactionhttp://en.wikipedia.org/wiki/Covalenthttp://en.wikipedia.org/wiki/Covalenthttp://en.wikipedia.org/wiki/Chemical_reactionhttp://en.wikipedia.org/wiki/Substituenthttp://en.wikipedia.org/wiki/Chromophorehttp://en.wikipedia.org/wiki/Reactive_dyes

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Sulfur: most commonly used dyes manufacturedforcotton in terms of volume. They are cheap, generally

have good wash-fastness and are easy to apply. The

dyes are absorbed by cotton from a bath

containing sodium sulfide orsodium hydrosulfite

http://en.wikipedia.org/wiki/Dyehttp://en.wikipedia.org/wiki/Cottonhttp://en.wikipedia.org/wiki/Sodium_sulfidehttp://en.wikipedia.org/wiki/Sodium_hydrosulfitehttp://en.wikipedia.org/wiki/Sodium_hydrosulfitehttp://en.wikipedia.org/wiki/Sodium_sulfidehttp://en.wikipedia.org/wiki/Cottonhttp://en.wikipedia.org/wiki/Dye

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Vat:essentially insoluble in water and incapable ofdyeing fibres directly. However, reduction in alkaline

liquorproduces the water soluble alkalimetalsalt of the

dye, which, in this leuco form, has an affinity for the

textile fibre

http://en.wikipedia.org/wiki/Alkaline_liquorhttp://en.wikipedia.org/wiki/Alkaline_liquorhttp://en.wikipedia.org/wiki/Alkalihttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Salthttp://en.wikipedia.org/wiki/Salthttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Alkalihttp://en.wikipedia.org/wiki/Alkaline_liquorhttp://en.wikipedia.org/wiki/Alkaline_liquor

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Stages of dyeing

1. Stock/Fiber dyeing

2. Sliver/top dyeing

3. Yarn dyeing1. Skein dyeing

2. Package

3. Beam4. Fabric/piece

1. Beck

2. Jet

3. Jig

4. Pad

5. Beam5. Garment

6. Dope

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Methods of printing

Direct

Discharge

Resist

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Types of printing

Block printing

Roller

Screen Rotary screen

Heat transfer