Desizing Process of Cotton Fabric

In this article, we are going to know about the process of desizing with enzyme of cotton fabric. This process is followed in the lab and described here as per followed steps.

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Introduction

Desizing is the process of removing the size materials from the warp yarns. The major desizing processes are enzymatic, oxidative, acid fermentation and removal of water-soluble sizes. Enzymatic desizing is the classical desizing process of degrading starch size on cotton fabrics using enzymes. Enzymes are complex organic, soluble bio-catalysts formed by living organisms that catalyze chemical reactions in biological processes. Enzymes are quite specific in their action on a particular substance. A small quantity of enzyme is able to decompose a large quantity of the substance, it acts upon. Enzymes are usually named by the kind of substance degraded in the reaction it catalyzes. Amylase is the enzyme that hydrolyses and reduces the molecular weight of amylose and amylopectin molecules in starch, rendering it water-soluble enough to be washed off fabric. Effective enzymatic desizing requires strict control of pH, temperature, water, hardness, electrolyte addition, and choice of surfactant.

Recipe

Chemicals / Parameters	Quantity
Wetting agent	1 g/L
Sequestering agent	1 g/L
Acetic acid	0.5 g/L
Enzyme	5 g/L
pH	6-7
M:L	1:40
Time	20–30 minutes
Temperature	70℃
Sample weight	5 gm
Total water	200 ml

Calculation

M:L = 1: 40 (M:L is more because it is done in an open bath)

Fabric = 5 gm

Total liquor = 5 ✕ 40=200 ml

So, M:L = 5: 200 (M:L is more because it is done in an open bath)

Chemicals: (g/L ✕ Total liquor) / (1000 ✕ Stock solution %)

Example: Wetting agent,

For 5% stock solution of wetting agent = (1 ✕ 200) / (1000 ✕ 5%) = 4 ml

Similarly, calculate the amount of other required chemicals.

Then, sum up the total required chemicals.

Then, required freshwater = (200- Total required chemicals) ml

Sample of Desized Cotton Fabric

Enzymatic Desized Cotton Fabric

Enzymatic Desizing Process Curve

Auxiliary Chemicals Functions

Wetting agent: It accelerates the wettability of material in solution, thus helping the easy penetration of chemicals into the substrate. It reduces the surface tension of water to allow it to spread drops on a surface, increasing the spreading abilities of a liquid.

Sequestering agent: In the absence of a water-softening plant in an industry, it is also possible to reduce the unwanted interference of heavy metal ions during soaping or dyeing by a sequestering agent. A sequestering agent is a substance that suppresses a property or reaction of metal ions without the removal of that metal from the system. The most common sequestering agent is EDTA, known as ethylenediamine m- tetra acetic acid.

Acetic acid: Its function is to control pH in the process.

Enzymes: Enzymes are complex organic solutions, biocatalysts, formed by living organisms that catalyze the chemical reactions in the biological process. The enzymes hydrolyze and reduce the molecular weight of amylose and amylopectin molecules in starch.

Conclusions

The enzymatic desizing process of removing sizing materials from the goods is applied for specific benefits of production. Sizing is applied in warp yarn before weaving. Before dyeing, garments need to desize. Therefore, enzymatic degradation removes the size starches.