Textile Dyeing – Dyeing Types

Textile Dyeing – Dyeing Types

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There are many dyes available on the market to dye both yarn or fabric. Below follows a list of these dyes and some more information that can assist Textile Engineers or even a novice that would like to do some home DIY projects.

Direct dyes:
These dyes need added sodium salt of sulphuric acid and have a direct affinity to cellulosic fibre. They are water soluble and needs the salt addition in the dye bath. The dye should be applied at alkaline or neutral conditions. This dye is also the most inexpensive.

Basic dyes:
This dye requires added ammonium, sulphonium or a uxonium salt. It is known to produce a bright shade. This dye is water soluble and can be applied on cotton, cellulosic fibre and leather.

Acid dyes:
Chemically acid dyes belong to various subclasses such as nitro nitroso, monoazo, diazo, xanthance azine, quinolone and anthraquinone. It is water soluble and have affinity to wool, silk and nylon fibres. They are applied to the fibres in a neutral or acidic dye bath.

Mordant dyes:

These are the oldest natural dyes. They have no affinity to textiles but can be applied to cellulose or protein fibres in order to dye the fabric when they have been treated previously with metallic salt. This dye can be combined with metallic oxides to form an insoluble colour agent.

Sulpher dyes:
These are complex organic compounds containing sulphur. They are insoluble in water and usually applied to cotton for pastel shades due to its high wet fastness and poor light fastneness.

Azoic dyes:
These are not ready made dyes. Fibres are firstly infused with a coupling component like bitanepthol and then combined with a diazotized base to produce an insoluble dye. They are mainly used on cotton but can also be used for dyeing wool silk and fur.

Vat dyes:
These are fast acting cotton dyes that are insoluble in water. They are reduced by combining a strong reducing agent that is soluble in water. After the infusion they are again oxidized to their original insoluble form.

Reactive dyes:
These dye are combined with cellulose through chemical bonding when covalent bonds are produced. It has an excellent wash fastness and is used on cotton, wool, silk and nylon. Dyeing is carried out in an alkaline bath.

Disperse dyes:
This dye is suitable for synthetic fibres for example polyester, nylon, acrylic and cellulosic acetate. It is applied through a high temperature dyeing method and is widely used within the industry.