Kier Bleaching Process | Color Fastness Types

Kier Bleaching Process Applied in Textile Dyeing:

Bleaching in Kier is a discontinuous process. Kier bleaching is a very easy method. The Kier is made of cast iron coating inside the Kier by sodium silicate or stainless steel so that chemicals used cannot react with cast iron. Kier bleaching is a batch process.

Recipe of Kier Bleaching Process:

The recipe is presented below:

Caustic Soda: 0.3-0.8% (According to the weight of the textile materials),
Wetting Agent: 0.5-1% (According to the weight of the textile materials),
Soda Ash: 0.6-1% (According to the weight of the textile materials),
Hydrogen Peroxide (50%): 2.5-4% (According to the weight of the textile materials),
Sodium Silicate: 2-3% (According to the weight of the textile materials),
Magnesium Sulphate: 10 lbs 100 gallons,
pH Value: 10.7-10.9

Parts of Kier Bleaching Machine:

Different parts of the kier bleaching machine have listed in the following:

Kier bleaching process in textile
Fig: Kier bleaching process in textile
  1. Liquor or water spray,
  2. Pressure gauge,
  3. Safety valve,
  4. Manhole,
  5. Spreader valve,
  6. Steam valve,
  7. Mixing tank,
  8. Release valve.
Kier Bleaching Process in High-Pressure Boiler:

The bleaching solution prepared is separate. The Kier is loaded by 1/3 with the solution. The required amount of the cloth placed in the Kier. The temperature in the Kier raised gradually by applying steam up to 70°C until the air in the Kier was completely removed. Then the Kier closes and raises the temperature to 110°C remaining 1-3hrs to complete the bleaching. Then the washing is done with normal water.

Different Types of Color Fastness:

There are mainly three types of colorfastness. Those are presented in the below:

  1. Color Fastness to Washing,
  2. Color Fastness to Water,
  3. Color Fastness to Rubbing,
  4. Color Fastness to perspiration,
  5. Color Fastness to hot pressing,
  6. Color Fastness to light,
  7. Color Fastness to seawater,
  8. Color Fastness to chlorinated water.
Washing Fastness: 

When we use water, detergents, or soap it bears its previous color shade without feeding color after dyeing the fabric is termed as washing fastness or wet fastness.

Light Fastness:
We preserve the sunlight or light if the color shade is not changed. The lightfastness is better.

Rubbing Fastness:
Rubbing fastness agent is a chemical that will help to develop rubbing resistance power; this kind of agent is used.

Rubbing Fastness Improver:
If dyed material when faced with more abrasions, the color of materials is not fed is called rubbing fastness. Example: T.R.O

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