Textile Dyeing – Dyeing Pre-treatments

Textile Dyeing – Dyeing Pre-treatments

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Prior to any colouring technique, dye or print can be applied to cotton there are various preparations that the textile or grey fabric may need to undergo. This ensures the quality and durability of your end result.

Here is a list of the various pre-treatments:

Singeing:

During this process projecting hairy fibres are burned from the grey fabric’s surface by means of a gas flame. Both sides of the fabric are burnt with the flame. It helps in subsequent chemical process to follow and ensure that after dyeing or printing of singed fabric that the brightness, lustre and colour of the fabric is improved.

Desizing:

During this process any starch that may be present is removed from the grey fabric. An enzyme is used to degrade and remove the starch. If the starch is not removed any subsequent chemical treatments or dyeing on the fabric will be irregular, which will cause a defective dyeing or printing technique.

Scouring:

This is the process of removing natural impurities present in the cotton fibre. Caustic soda or ash is used as scouring agent for cotton fabric, in order to enhance the stability of your end result.

Bleaching:

It is the process of removing any natural colouring that may be present in the cotton fibre. Hydrogen peroxide, bleaching powder or other bleaching agents can be used. Hydrogen peroxide is the best and most commonly used bleaching agent. If the bleaching treatment is not carried out before dyeing or printing the colour hue and shade may be compromised.

Mercerization:

This is a chemical pre-treatment on cotton that improves the strength, absorbency, lustre, softness, dye and chemical consumption of the fabric. The process involves the fabric to be treated under tension in a 20% caustic soda solution for a period of time depending on its mass.