Faults & Damages of Bleaching

Faults of Bleaching: The faults of bleaching are given below,
  1. Harsh Feeling: As stabilizer if we use sodium silicate then this silicate is precipitate on the fabric and that’s why fabric become harsh.
  2. Chloramines Reaction: Chloramine reaction will occur in hypochlorite bleaching. So antichlor treatment is done. For that the permanency of whiteness is damaged and fabric becomes yellowish.
  3. Uneven Bleaching:
    1. For all types of machine faults.
    2. Faults in bleaching agent.
    3. In efficient dosing.
    4. Inadequate raw materials.
  4. Alkalinity may remain: To destroy alkalinity we used acetic acid. Dye hydrolysis and dye wastage causes of alkalinity and also reduced the fastness.
  5. Residual peroxide causes uneven dyeing. Dye wastage and shade variation.
  6. Iron stain.
Damages of Bleaching: A number of varieties of product easily oxidized by cellulose which is known as oxy-cellulose. Now a days scouring and bleaching is a combination process. Loss of strength is the causes of formation of oxy-cellulose. There are three point at which oxidizing agent can attack the glucose molecule.
Estimation of Damage:
  1. Physically: By testing strength before and after bleaching.
  2. Chemically: There are several methods. These are,
    1. Fluidity test.
    2. Copper number test.
    3. Methylene blue test.

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