Types of dyes and their properties

Dyeing may be defined as that which chemically or physically changes a substrate so that the reflecting light appears coloured. Types of dyes and their properties the substance which cuases this change of color to a substrate is called dye. The dyes should have following properties:

types of dyes and their properties

Types of dyes and their properties are bellow

  1. Intense color. 2. Solubility. 3. Substantivity. 4. Fastness.

There are various types of dye staffs present in the market in different brand name by different company. All the dye staffs are classified according to their applications which are briefly discussed below:

Direct dyes: These dye staffs are generally sodium salt of sulphonic acid. They have direct affinity to cellulosic fiber. Types of dyes and their properties are water soluble and needs salt addition in the dye bath, should be applied at alkaline or neutral condition. This dye staff is poor fastness to wash but cheaper.

Basic dyes: These types of dyes and their properties are generally ammonium sulphonium or auxonium salt, famous for bright shade, water soluble & application on cotton & other cellulosic fiber and leathers.

Acid dyes: Chemically acid dyes belong to various subclasses such as nitro.nitroso, monoazo. diazo. xanthane. azine, quinoline, anthraquinone etc. These types of dyes and their properties are water soluble and have affinity to wool, silk and nylon fibers. They are applied to the fibers through neutral or 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 fibers when they have been mordented previously with metallic salt. These dye staffs are capable of combining with metalic oxides to form insoluble color on the fiber.

Sulphur dyes: These types of dyes and their properties are complex organic compounds containing sulphur. 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. Fibers are firstly impregnated with a coupling component like B-nepthol and then combined with a diazotised base to produce insoluble dye staffs into the fiber. Their main use on cotton but also can be dyed silk & fur.

Vat dyes: These types of dyes and their properties are very fast color on cotton & insoluble in water. They are reduced by strong reducing agent to produce leuco-vat & at this stage they are soluble in water. After impregnation they are again oxidised to their original insoluble form.

Reactive dyes: These types of dyes and their properties are directly combines with cellulose by chemical bonding i.e. covalent bonds are produced. They have excellent wash fastness. Mainly used on cotton and can also be applied on wool, silk & nylon. Dyeing is carried out into a neutral bath but fixation is carried out in an alkine bath.

Disperse dyes: These types of dyes and their properties are very suitable for synthetic fibers for example polyester, nylon, acrylic, cellulose acetate, etc. High temperature dyeing methods are suitable for these dye staffs but carrier dyeing method can cal also be applied.