What are the issues in dyeing with Direct Dyes?

1. Direct dyes are the coloring products that are easy to apply and are inexpensive. You can easily get any colorant from direct dyes exporters in your city. These dyes are classified on the basis of three things – chemical structure, dyeing properties and fastness properties. Out of these things, chemical structure is least important for the dyer but those who are interested in dye chemistry find chemical structure important factor. There are mainly three classes of direct dyes – A, B, and C. Class A direct dyes are self-leveling. Dyes that belong to this group have good leveling properties and are able to dye uniformly even with the addition of electrolyte when the process of dyeing starts. These dyes may need more amounts of salt to exhaust well. Class B direct dyes are salt-controllable. Dyes belong to Class B group have relatively poor leveling or migration properties. You can dye the batch uniformly by controlled electrolyte addition when the dye bath hits the dyeing temperature. Class C direct dyes are salt and temperature controllable dyes. Dyes belong to Class C group have poor leveling or migration properties. You can control their dyeing rate by controlling the rate of increase of temperature and salt addition.

2. Direct dyes are able to produce full shades on linen and cotton and can be also used for other fabrics like silk, rayon, and wool. You can find varieties of bright shades of direct dyes in the market. The process of dyeing is not a complex one. It is usually performed in a neutral or slight alkaline dye bath, at or near boiling point. Apart from dyeing uses, direct dyes are also used as pH indicators and as biological stains. How the professionals apply Direct Dyes? Direct dyes are used with electrolyte at or near boiling point in the machines. But the operation in HTHP dyeing machines is different as it is carried out at temperatures above the boil if the material is pure and blended yarn. Including Alkali, sodium carbonate may be made with direct dyes that are acid-sensitive and with hard water to improve the solubility of dye. The cellulose absorbs the direct dye when immersed in the solution until equilibrium is attained. The absorption rate and equilibrium exhaustion differ from dye to dye. Direct dyes can be used and applied by batch dyeing methods, by semi-continuous methods, and by continuous methods. Many direct dyes are usable for applications by combined dyeing and scouring. In this process, professionals use soda ash and non-ionic detergent. You can avail bright dyes from direct dyes exporters in your city or area. Many manufacturers and suppliers are providing their products to overseas customers. You can get the products at reasonable rates. This Article is Originally Published on: https://www.olaladirectory.com.au/what-are-the-issues-in-dyeing-with-direct-dyes/