Bleaching plays a vital role in wet processing. Bleaching is used for removing natural color of the knitted fabrics. During pre-treatment, different parameters of the knitted fabrics are maintained strictly. Various types of bleaching agents can be used for bleaching.
Bleaching agents are used for different types of fiber. Textile fiber may be natural or synthetic. Due to different types of fiber, bleaching agents also differs from each other. Bleaching can be classified as the follows:
Oxidizing Agents
1. Ozone (O3)
2. Bleaching Powder
3. Hydrogen Per Oxide (H2O2)
4. Sodium Hypochloride (NaOCl)
5. Sodium Chlorite (NaclO2)
6. Potassium Dichromate (K2Cr2O7)
7. Potassium Permanganate (KMnO4)
8. Per Acetic Acid (CH3COOH)
9. Sodium Per Oxide (Na2O2)
10. ETC
Above no. 1 and 2 agent uses for home purpose.
Above no.3, 4 and 5 agent uses for industrial purpose.
Above no. 6, 7, 8 and 9 agent uses for washing purpose.
Reducing Agent
1.Ferrose Sulphate (FeSO4)
2.Zinc Dust (ZnO)
3.Stannous Chloride (SnCl2)
4.Sulpher Dioxide (SO2)
5.Sodium Hypo Sulphite (Na2S2O2)
6.Glucose
7.Hydrogen Sulphide (H2S)
8.ETC
Different types of bleaching agents are used for different types of fibers. All of the bleaching agents hydrogen per oxide is called as universal bleaching agent.
Hydrogen per oxide is a kind of very gentle bleaching agent which is easy for application and can apply with any types of fiber. Permanent treatments can also be possible with hydrogen per oxide.
Discontinuous or semi-continuous process: Bleaching agent is used for fiber discontinuously or semi-continuously. Bleaching tank, Jigger, Padder, Kier are used for treatment with bleaching agent.
Continuous process: Bleaching treatments is used as per sequence of treatment. J-Box is also used for continuous process.
The following points must be considered during bleaching:
1.Bleaching Agent
2.Wetting Agent
3.Sequestering Agent
4.Stabilizer
5.Alkali
6.Materials and Liquor ratio
7.Temperature
8.Application time
There are a large number of corporations manufacturing machines. The properties of machines should meet the requirements of operation. What is more, chemical properties should also be focused.