Water Hardness factor while dyeing fabric or textile yarn is discussed below:
Hard Water
The presence of calcium, magnesium, salt i.e. bicarbonates, sulphate, chlorides in water is called hardness of water. The water which contains these slats is called hard water.
Hard water is not suitable for textile dyeing. Why the hard water is not suitable for dyeing I will tell it you now. Just keep reading this article.
Hard water does not easily form lather with soap as the salt of Ca and Mg react with soap to form insoluble organic salts. So it creates problem during scouring before dyeing fabric or yarn.
Here the reaction is –
CaSo4 + 2RCooNa = (Rcoo)2 Ca + Na2So4
MgSo4 + 2RCooNa = ( RCoo)2 Mg + Na2So4
Classification of Hard Water:
1. Temporary Hardness: Temporary hardness is due to the presence of bi-carbonates of Ca & Mg. Co2 is normally present in natural water. Thus Ca(HCO3), Mg(HCO3)2 formation is done. Separation of CaCO3 is performed easily by boiling.
Ca(HCO3)2—–CaCO3 + CO2 + H2O ( If heated)
MgCO3 + H2O— Mg(OH)2 + CO2 [ CaCO3 + Mg ( OH)2 ] ( if heated)
2. Permanent Hardness: It is due to the presence of chlorides or sulphate of Ca & Mg. These salts do not decompose on boiling. So lather is formed after sufficient addition of soap.
C17H35COONa + CaSO4 – (C17H35Coo)2Ca + Na2So4
Effects of Hardness on Dyeing or other textile process:
- Insoluble soap deposition during scouring creates discolored patches.
Spots impervious to dye liquor, finally un-uniform dyeing is occurred.
Hard Water
The presence of calcium, magnesium, salt i.e. bicarbonates, sulphate, chlorides in water is called hardness of water. The water which contains these slats is called hard water.
Hard water is not suitable for textile dyeing. Why the hard water is not suitable for dyeing I will tell it you now. Just keep reading this article.
Hard water does not easily form lather with soap as the salt of Ca and Mg react with soap to form insoluble organic salts. So it creates problem during scouring before dyeing fabric or yarn.
Here the reaction is –
CaSo4 + 2RCooNa = (Rcoo)2 Ca + Na2So4
MgSo4 + 2RCooNa = ( RCoo)2 Mg + Na2So4
Classification of Hard Water:
1. Temporary Hardness: Temporary hardness is due to the presence of bi-carbonates of Ca & Mg. Co2 is normally present in natural water. Thus Ca(HCO3), Mg(HCO3)2 formation is done. Separation of CaCO3 is performed easily by boiling.
Ca(HCO3)2—–CaCO3 + CO2 + H2O ( If heated)
MgCO3 + H2O— Mg(OH)2 + CO2 [ CaCO3 + Mg ( OH)2 ] ( if heated)
2. Permanent Hardness: It is due to the presence of chlorides or sulphate of Ca & Mg. These salts do not decompose on boiling. So lather is formed after sufficient addition of soap.
C17H35COONa + CaSO4 – (C17H35Coo)2Ca + Na2So4
Effects of Hardness on Dyeing or other textile process:
- Insoluble soap deposition during scouring creates discolored patches.
Spots impervious to dye liquor, finally un-uniform dyeing is occurred.
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