Bleaching definition necessity objectives and types are given below:
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The chemical process by which natural color matter is destroyed from textile products is called bleaching.
Textile bleaching is a process by which natural dyes are removed from textile products. With the help of the desizing and scouring method of textile products, the absorption capacity of textile products (cloth) is increased by removing its starchy substances, fats, waxes, and other wastes. All that is left is the natural dye which is removed by the bleaching method and the fabric is brightly whitened, which makes the fabric hydrophilic and which facilitates the subsequent dyeing, printing, and finishing process.
The goal of an effective bleaching method is to ensure that the fabric is whitened in a real and permanent way, keeping a watchful eye so that the fabric is bleached evenly without excess or minimal bleaching. Also, ensure that no damage is done to the fabric during bleaching. Copper Number Cuprammonium Fluidity, Tensile strength, etc. can be measured by measuring the physical or chemical damage to the fabric with the help of the testing method. Based on which it is possible to use a satisfactory control method.
Knowing the effect of different bleaching agents on different conditions of cotton bleach such as density, pH, temperature and time, etc. makes it easier to choose the optimal bleaching conditions for a particular bleaching agent.
The necessity of Bleaching:
The need for bleaching in the textile wet processing industry is immense. The process of desizing and scouring removes starch from the fabric and other impurities including natural oils, fats, waxes, etc., and completes the finishing ability of the fabric. Bleaching removes the natural color of the fabric and whitens the fabric in a real and permanent way.
If the absorption capacity of the fabric is not increased, various dyes and chemicals will not be able to enter the fiber easily in the subsequent dyeing, printing, and finishing process. As a result, there will be various difficulties in these processes. Waste of dying chemicals will increase the cost. Moreover, it will not be possible to produce quality products.
As a result, it will be difficult to survive in a competitive market. In addition, all the products that will be marketed as the bleached finished product, such products cannot be imagined without bleaching.
Thus, it is undeniable that the bleaching process is necessary to save time and money and to ensure the production of quality products.
Objectives of Textile Bleaching:
Bleaching is done for the following purposes e.g.
1. Remove natural colors from fabrics.
2. Ensuring that the fabric is genuine and durable white.
3. Oil the fabric to make it hydrophilic to facilitate subsequent finishing processes such as dyeing, printing, etc.
4. Increase the absorbency capacity of the fabric.
5. Subsequent processes save time, labor, and chemicals.
6. When bleaching fabrics, a uniform shade is available in the dyeing.
Types of Bleaching:
Bleaching is usually of two types
1. Hand Bleaching
2. Machine Bleaching
1. Bleaching definition necessity objectives and types-Hand Bleaching:
If any fabric or yarn is bleached in a container with a lid without any type of machine or automatic system, it is called hand bleaching. Such hand bleaching methods were followed before the invention of modern machinery. Hand bleaching is now practiced in the handloom or small-scale dyeing, printing, and textile similarity cottage industries i.e. where bleaching of yarn or cloth in small size is required. However, in these cases, the bleaching process is not as perfect as the machine.
In the case of the hand bleaching process, especially cotton, sodium hypochlorite, bleaching powder, and hydrogen peroxide are commonly used as bleaching agents. However, due to the high cost, sodium hypochlorite is not used except in special cases. The use of bleaching powder and hydrogen peroxide is much higher in hand bleaching.
In the case of bleaching by bleaching powder, first, the bleaching powder is mixed well with a little water, then the water is gently added and the clean part is taken as a solution of bleaching powder. Cotton bleaching usually involves taking (2 or 3-degree Towadel) of bleaching powder. Bleaching solution is best done at a temperature of 20 to 25 centigrade. Bleaching with bleaching powder is usually done at room temperature.
However, for bad types of cotton bleaching, the solution is sometimes slightly heated. Cotton should be soaked in a bleaching container for 30 minutes to one hour. However, at this time sometimes the cotton has to be inverted. Care should be taken to ensure that the cotton is completely immersed in the solution during bleaching. Otherwise, the oxygen in the air softens the cotton. This process needs to be done as soon as possible otherwise there is a possibility of damage to the cotton.
2. Bleaching definition necessity objectives and types-Machine Bleaching:
The process by which a cloth or yarn is bleached with the help of a machine is called Machine Bleaching. Many advanced and modern bleaching machines have been invented. All these machines can easily complete the bleaching process in a very short time. However, it is used in large industrial establishments where work is done on a wide scale.
Such modern and high-capacity machines are not used for small-scale industries. With this modern bleaching machine, on the one hand, a lot of products can be given in such a short time, and on the other hand, perfect bleaching can be done on different types of fabrics as there are different control systems. However, if the temperature, pH, time, etc. of such machines are not under control, there can be serious damage.