Direct Dyes

Direct dyes belong to the azo dye group and cover a wide variety of molecules that are soluble in water. Direct dyes are relatively inexpensive. They are available in a full range of hues but are not of high color brilliance. They show poor to moderate fastness to washing. They are therefore used on materials where good fastness is not of prime importance. And direct dyes have a wide range of uses in textiles, plastics, cosmetics, and hair dyes. They are mainly used to color cellulosic materials in alkaline or neutral solutions. Optimum conditions vary, but dyeing is usually carried out at or near boiling point in the presence of an electrolyte such as sodium chloride or sodium sulphate. With increasing depth of shade, the wet fastness decreases to such an extent that dyeing must generally be after-treated. The majority of direct dyes are characterized by excellent affinity to the fiber.

As a professional supplier of high-efficiency dyes, Alfa Chemistry has the ability to provide customers with a comprehensive range of direct dyes including:

• Direct Fast Dyes
• Direct Blend Dyes
• Other Direct Dyes

Features of Direct Dyes

Mechanism of Direct Dyes

When cellulose fibers are immersed in water, their amorphous regions swell to produce small pores in the order of 20-100A (Angstrom) and acquire a negative charge. Dye molecules also split in solution and release dye anions. Furthermore, electrolytes release sodium cation that gets attached to the dye molecules and carry it to the fiber surface. It also reduces the extent of osmotic work required to transfer the accompanying metal ions. The sodium salt of the dye molecule is then deposited on the fiber surface. The direct dye gradually diffuses into the swollen cellulose matrix. There it places itself next to the polymer chains by hydrogen bonding and van der Waals forces, whereby the fiber can be dyed.

Alfa Chemistry is committed to becoming a first-class, low-carbon, environmentally friendly dye supplier. Our mission is to provide customers with full specifications of high-quality dyes. We are also constantly expanding our product database to meet the wide range of customer needs. You are welcomed to contact us for more direct dyes.

It is important to note that our products are for research use only and are not for clinical use.