It is necessary for human beings to wear clean clothes, as social clothes give unpleasantness and may also harbor germs in the skin. Therefore, clothes should always be clean, which requires some technical knowledge. Laundry work is one of the most important and heavy task that falls on a housewife. The process and materials used in laundering the fabric are mainly responsible for retaining the strength and serviceability, of the clothes. A Housewife must be informed about how various fibers react to the different processes and reagents used in laundering. Laundering of clothes consists of two processes: 1. The process of removing dirt (2) The process of finishing them to regain the appearance of neatness as a new fabric. The most important requirement for laundry work is water.
Water suitable for Laundering
Water is the medium through which we wash different kinds of clothes and remove dust and dirt from the surface of the cloth. The functions of water are as follows:
1. Water is able to penetrate into the fiber and cause wetting.
2. Movement of water particles helps to remove the non greasy dirt from the fabric.
3. Water is an excellent solvent, therefore soluble dirt and stains are removed during steeping process.
There are two types of water commonly used in laundry work. They are:
1. Hard water:
In most water, many substances from the surface of the earth are dissolved, especially calcium, magnesium and sodium carbonate which causes hardness in water. The presence of these salts and impurities make water unsuitable for laundry work. Because it is very difficult to produce lather in hard water and also it destroys the fiber. These water impurities are harmful both in the manufacture and the washing of fabrics. During the fabrication of cloth, water impurities are deposited on the fibers, which detract from their finish and appearance. Since, larger quantities of soap have to be used in order to produce lather. Often chemicals and bleaches are used to make washable clothes look presentable. With all these harshness, the fabric discolors and destroys quickly.
2. Soft water:
Soft water is the most suitable one for laundry work, since it is pure, free from impurities, and also contains less than 4% of hardness. Soft water washes whiter, brighter, saves soap and makes fabrics last longer.
Temporary Hardness of Water
The presence of calcium or magnesium bi-carbonate in water is called ‘temporary hardness’. It is so said as it can be removed by heat without the use of any chemicals. By boiling, the carbon-dioxide is driven off and the insoluble calcium carbonate is precipitated as chalk and the water is softened.
Permanent Hardness of water
Hardness, caused by all other compounds of calcium and magnesium, generally sulphates, chlorides and nitrates is known as ‘permanent hardness’. This hardness can only be removed by ‘distillation’ or by the use of chemicals.
Softening of Water
Most water contain either temporary or permanent hardness and the methods employed in softening them aims at removing all the hardness without leaving the water alkaline.