What is Solvent Dyeing | Types and Characteristics of Solvents Used in Textile Processing

Last Updated on 18/12/2021

What is Solvent Dyeing?
Solvent dyeing is a dyeing process carried out from a continuous non-acqueous phase. Solvent dyeing is a new trend and most of the modern textile mills are eagerly implementing this dyeing method to dye the fabric. Here solvent is used as dyeing media. But water may be added to assist dyeing process. Since the introduction of hydrophobic fibers like cellulose acetate in 1920’s solvent have been considered for dyeing because it was not possible to dye such fibers with ionic dyes and water.

solvent dyeing

In recent times, there has been a focus on process sustainability and products that focus on a green philosophy, that eliminate or reduce the use or generation of hazardous compounds, and that use a minimum of energy in the process sequence. Textile wet processing leans on water and volatile organic compounds, such as solvents, surfactants, coloring matter, and oxidizing or reducing agents, which are hazardous in nature and generate a high level of pollution at disposal.

In the path toward sustainable textile manufacturing, water has been replaced with solvents to dissolve dyes to enable uniform adsorption and exhaustion onto the textile materials. Various solvents serve this purpose, indeed supercritical carbon dioxide serves better for different textile fibers with disperse dyes as the medium for the transference of dyes in and out of fiber polymer; this method was initially proposed by Schollmeyer.

Properties / Characteristics of Solvents:
An ideal solvent for textile processing should have the following characteristics-

  1. Non-toxic.
  2. Non-flammable.
  3. Non-corrosive.
  4. Inert to textile materials.
  5. Stable to repeated distillation.
  6. Low specific heat.
  7. Low heat of evaporation.
  8. Readily available.
  9. Economic feasibility.

You may also like: Waterless Dyeing Technology in Textile Processing

Types of Solvents Used in Textile Processing:
Some solvents of chlorinated hydrocarbons of aliphatic series posses most of the mentioned requirements and hence are being used as solvents are extensively used such as-

  1. Tri-chloro Ethylen (TCE).
  2. Per-chloro Ethylen (PCE).
  3. Methyl Chloroform (MC).

All three solvents are almost equally suitable but tri-chloroethylene has very high stability to decomposition and hence isomers preferable.

Advantages of Solvent Dyeing:

  1. High wettability and dyeability.
  2. Rapid dyeing with minimum energy requirements.
  3. Better levelness and dye yield compared with better fabric aesthetics.
  4. Solvent is being recycled, so the effluent control problem is eliminated.
  5. Less time required.

Disadvantages of Solvent Dyeing:

  1. Solvents are expensive, so higher production cost.
  2. Problem in equipments availability.
  3. Existing dye can not be used in full range.

You may also like:

  1. Sustainable Dyeing Process in Textile Industry
  2. Water Consumption in Textile Processing Industry
  3. Waterless Dyeing Technology in Textile Processing
  4. Solvent Scouring Process with Advantages and Disadvantages

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