What is Biopolishing of Textiles? | Process of Bio-polishing in Textile

An Overview of Bio-polishing in Textile

Sabina Yesmin Rony

Dept. of Textile Engineering
Dhaka University of Engineering & Technology (DUET)
Email: sabina.yesmin.520@facebook.com

What is Bio-polishing:
Bio-polishing is a finishing process that enhances fabric quality by decreasing the pilling tendency and fuzziness of (cellulose) knitted fabrics .This finishing process applied to cellulose textiles that produces permanent effects by the use of enzymes .This process removes protruding fibres & slubs from knitted fabrics, significantly reduces pilling, softens fabric hand and provides a smooth fabric appearance .

Bio-polished garment

About the Bio-polishing :
The bio-polishing process targets the removal of the small fiber ends protruding from the yarn surface and thereby reduces the hairiness or fuzz of the fabrics. The hydrolysis action of the enzyme weakens the protruding fibers to the extent that a small physical abrasion force is sufficient to break and remove them. Bio polishing can be accomplished at any time during wet processing but is most convenient performed after bleaching.

It can be done in both continuous or batch processes. However, continuous processes require some incubation time for enzymatic degradation to take place. Removing the fuzz makes the color brighter, the fabric texture more obvious, and reduces pilling. Unfortunately, the treatment also reduces the fabric strength. Smoother yarns also increase the fabric softness, appearance and feel. Since it is an additional process, the bio-polished garments may cost slightly more. Next time you buy apparel, look for the label “Bio-Polished.

Object of Bio-Polishing :

1. To removes protruding fibres & slubs
2. To removes Hairiness, fluffs and pills .
3. To Prevented material sticking .
4. To softens fabric hand & improved handle .
5. To achievement of surface smoothness and a clear structural appearance & improved luster .
6. To imporved material texture relaxation & increased flexibility.
7. To improved sewability & Fast to washing, low pilling tendency, no napping in use, or during care operation.
8. To Converted fabrics from Poor quality, uneven, napped, knoppy material surface to lustrous, soft, elegant,top quality with a fine, high quality surface appearance.

Process of Bio-polishing :
There are two process of Bio-polishing .

1. Dyeing followed by bio-polishing.
2. Bio-polishing before Dyeing .

Process sequence of Dyeing followed by bio-polishing :

Scoured &bleaching sample
↓
Dye addition
↓
Salt addition
↓
Soda ash addition
↓
Dyeing
↓
Hot wash
↓
Hot wash
↓
Soaping (at boil temperature )
↓
Hot Wash
↓
Cold wash
↓
Enzyme treatment
↓
Cold wash
↓
Drying

Process sequence of Bio-polishing before Dyeing :

Scoured & bleaching sample
↓
Bio-polishing
↓
Cold wash
↓
Drying
↓
Dye addition
↓
Salt addition
↓
Soda ash addition
↓
Hot wash
↓
Hot wash
↓
Soaping (at boil temperature )
↓
Hot Wash
↓
Cold wash
↓
Drying

Process Variables :
To achieve optimum bio-polishing, the process variables have been varied as mentioned below ……

• Concentration : Concentration of enzyme: 0.5%, 1%, 2%, 2.5%, 3% & 4%.
• Temperature : Temperatures are 40 0C, 45 0C, 50 0C, 55 0C & 60 0C.
• pH : 3 - 4, 4 - 5 & 5 - 6.
• M : L : 1:5, 1:10, 1:15 & 1:20.
• Mechanical Agitation: Vigorous Stirring, Medium Stirring & Without Stirring.

Standard Recipe for Bio-polishing :

• Concentration of Enzyme = 3%
• M : L = 1:10 
• Temperature = 55 0C
• Time = 55 minutes
• pH = 4 - 5

Application Method :
Enzymatic cellulose degradation is also possible during reactive dyeing. Here the dyeing process as well as bio-polishing will be affected. We can applied this process Number of washes, time, cost and energy can be saved by this one bath method. However, it should be noted that there is some reduction in colour yield of reactive dyeing. This is because reactive dyeing is carried out in acidic pH during bio-polishing. But precaution is taken during addition of soda-ash as reactive dyes require alkaline condition for its fixation. The fabric is made neutral before adding soda-ash. It is found that neutral stable enzymes are more suitable in this type of one bath treatment.

Advantages & Disadvantages :

1. Depth of shade increases when enzyme treatment is given before dyeing but the depth decreases when enzyme treatment is given after dyeing.
2. Wash fastness of the enzyme treated sample after dyeing is good but Wash fastness of the enzyme treated sample before dyeing is very poo .
3. One bath application saves energy, time & cost but the bio-polishing effect is not as good as the two bath method .
4. Decreases the Pilling tendency .
5. Loss in weight.
6. Loss in strength.

Conclusion :
With the advantages of Bio-polishing there have some disadvantage of this process . So ,we have need to handle the process with carefully by controlling Concentration ,Temperature ,pH , M:L , & Time .

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