Today Post::Different Dyestuff used in Fabric Dyeing

Different types of dyestuff used in Fabric Dyeing

Direct Dyes: These dye staffs are generally sodium salt of sulphonic acid. They have direct affinity to cellulosic fibre. They are water soluble and need salt addition in the dye bath should be applied at alkaline or neutral condition. Poor fastness to wash but cheaper.
Basic Dyes: These are generally ammonium, sulphonium or auxonium salt famous for bright shade. Water soluble and application on cotton and other cellulosic fibre and leathers.
Acid dyes: chemically acid dyes belongs to various to various sub classes such as nitro-nitroso, monoazo, diazo, xanthane azine, quinoline, anthraquinone etc. they are water soluble and have affinity to wool, silk and nylon fibres. They are applied to the fibres through neutral of acid dye bath.
Mordant Dyes: they are the oldest natural dyes. They have no affinity to textiles but can be applied to cellulose or protein fibres when they have been mordented previously with metallic salt. These dye staffs are capable of combining with metallic oxides to form insoluble color on the fibre.
Sulpher Dyes: these are complex organic compounds containing sulpher. They are insoluble in water but soluble under reduced condition. They are usually applied at cotton for cheaper shades, have high wet fastness but poor light fastness.
Azoic Dyes; these are not readymade dyes. Fibres are firstly impregnated with a coupling component like bita nepthol and then combined with a diazotized base to produce insoluble dye staffs into the fibre. Their main use on cotton but also can be dyed silk and fur.
Vat Dyes: They are very fast color on cotton and insoluble in water. They are reduced by strong reducing agent to produce leuco-vat and at this stage they are soluble in water. After impregnation they are again oxidized to their original insoluble form.
Reactive Dyes: These dye staffs directly combines with cellulose by chemical bonding I,e covalent bonds are produced. They have excellent wash fastness. Mainly used on cotton, can also be applied on wool, silk & nylon. Dyeing is carried out into a neutral bath but fixation is carried out in an alkynes bath.
Disperse Dyes: These dye staffs are very suitable for synthetic fibres for example polyester, nylon, acrylic, cellulose acetate, etc. High temperature dyeing methods are suitable for these dye staffs but carrier dyeing method can also be applied.