The standard recipes for reactive dyestuffs given in the examples provided by dyestuff manufacturers often do not include the addition of surfactants such as dyebath lubricants. Doe this mean that they are not required?
In the dyeing of cotton with reactive dyes, because hydrophilic fibers are dyed with water-soluble dyestuffs, the dyeing itself does not require the use of surfactants. However, in the dyeing of cloth, it is difficult to spread the cloth out in the dyebath, and so it is often dyed in rope-form, but because it is sometimes difficult to circulate the liquid over the cloth, rope marks can easily form. The use of a dyebath lubricant is recommended as a method for dealing with this problem. The use of cold and warm dyeing dyestuffs when the temperature of the dyeing is below 55°C means the fiber is dyed while it is in a hard state, making a dyebath lubricant especially important for improving the quality of the dyeing. When dyeing is conducted at a temperature above 60°C with warm and hot dyeing reactive dyestuffs, however, the fiber itself softens and spreads easily, so the use of a dyebath lubricant is not as important.
However, when the solubility of a reactive dyestuff is reduced due to factors such as association, the use of a surface-active dyebath lubricant can result in a dispersion effect. Furthermore, when a small amount of wax still remains on the substrate due to insufficient scouring, the use of a dyebath lubricant can promote the permeation of the dye liquid. Thus to lower the degree of risk in dyeing, the use of an appropriate dyebath lubricant is recommended.
In the dyeing of cotton with reactive dyes, because hydrophilic fibers are dyed with water-soluble dyestuffs, the dyeing itself does not require the use of surfactants. However, in the dyeing of cloth, it is difficult to spread the cloth out in the dyebath, and so it is often dyed in rope-form, but because it is sometimes difficult to circulate the liquid over the cloth, rope marks can easily form. The use of a dyebath lubricant is recommended as a method for dealing with this problem. The use of cold and warm dyeing dyestuffs when the temperature of the dyeing is below 55°C means the fiber is dyed while it is in a hard state, making a dyebath lubricant especially important for improving the quality of the dyeing. When dyeing is conducted at a temperature above 60°C with warm and hot dyeing reactive dyestuffs, however, the fiber itself softens and spreads easily, so the use of a dyebath lubricant is not as important.
However, when the solubility of a reactive dyestuff is reduced due to factors such as association, the use of a surface-active dyebath lubricant can result in a dispersion effect. Furthermore, when a small amount of wax still remains on the substrate due to insufficient scouring, the use of a dyebath lubricant can promote the permeation of the dye liquid. Thus to lower the degree of risk in dyeing, the use of an appropriate dyebath lubricant is recommended.
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