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What is scouring process and types

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Today I will talk to you about What is scouring process is and its types?

Scouring

The main goal of the scouring process is to remove natural and concentrated waste from textile products. This is the second step of textile wet processing. The implementation of this process results in a cleaner product and greater shear capacity; which is crucial for subsequent bleaching, dyeing, printing, and finishing processes.

The desizing process is the de-starching process. That means removing starch from textile products. Which is dissolved by liquid and washed away by a hydrolytic or oxidative method of desizing. Oils, Fats, Wax, and other waste products remain in the fabric even after removing the starch from the fabric. Which in turn hinders the shearing capacity of the fabric. As a result, subsequent bleaching, dyeing, printing, and finishing processes cause various difficulties. To overcome these problems, it is necessary to remove waste from the cloth through the scouring process. This method is also called Keyring, Kier boiling out, etc.

The main purpose of the cotton scouring process is to clean the fabric naturally by removing waste from the fabric and increasing the water absorption capacity of the fabric. However, care should be taken so that the physical and chemical properties of the fabric are not damaged. Therefore, the wetting process in which alkali or detergent is used to remove oils, fats, waxes, and other wastes from textile products to make the textile product naturally clean and more water-absorbing is called squaring. As a result, the fabric is suitable for subsequent bleaching, dyeing, printing, and finishing processes.

Method of Scouring:

What is the scouring process and types? Many advanced machines for scouring have been invented. The main ingredient in scouring is alkali. Thus the method of scouring by alkali can be considered in three ways.

1. Lime acid soda ash process

2. Caustic soda process

3. Soap soda ash treatment for color goods

1. Lime acid soda ash process:

In this method, the cloth is dipped in 2–4% milk of lime (calcium hydroxide) solution. The cloth is then boiled for several hours at a pressure of 20 pounds / square inch and 125°C in the presence of a large amount of calcium hydroxide. Until saponifiable oil and wax are converted into insoluble calcium soap. Pectose and pectin are hydrolyzed to pectic acid in the form of insoluble calcium pectate. The compounds in proteins and amines are hydrolyzed and dissolved.

What is the scouring process and types? All these soluble wastes are removed by washing the clothes. The cloth is then piled in 20 ° (toadel) hydrochloric acid (HCl) solution. When calcium soap and pectase are converted to soluble calcium chloride and washed away in free fatty acids and pectic acid and soluble substances. The fabric is then heated by a solution of sodium carbonate (NaCO3) in the presence of resin soap. Both the fatty acids in the boiling process and the pectic acid are rapidly dissolved by sodium carbonate which can be easily washed away.

2. Caustic Soda Method:

This method is the most widely used in scouring. In this method, cotton cloth is scouring using a device called Kier boiler using the caustic soda as the main scouring chemical in the discontinuous process. Kier is a special type of vessel made of cast iron or stainless steel. Its capacity ranges from 500 pounds to 5 tons, but more than 3 tons of Kier is used. Boiling cotton cloth in 2 to 5 percent caustic soda or sodium hydroxide solution by weight in this machine removes the impurities inside the cloth. In addition, caustic soda is used as a scouring chemical and this cotton fabric is scouring in a continuous process.

The (J-Box) and (Vapor Lock) methods are one of them, the J-box machine looks like the letter ‘J’. It is a special type of container made of stainless steel or ceramic with a daily production of 40 tons. In J-box, 5 to 9 percent of the weight of the cloth can be removed by using caustic soda and covering the cotton cloth. The vapor lock method is a modern scouring method. In this method, cotton fabric can be scouring using 5 to 9 percent of its weight using caustic soda in a very short time.

3. Soap soda ash treatment for color goods:

The modern method for color oven cloth scouring is scouring with sodium carbonate solution. It usually uses 2.5% sodium carbonate by the weight of the fabric. Scouring is done by soap or by a solution of sodium carbonate and soap and at low pressure in a winch machine or open kier. Some fabrics are made of colored yarn, woven, and woven with white yarn. And for this colorful designs are made on the fabric. Such knitted fabrics require scouring and bleaching. This is because dirty fabric, yarn, or machine stains can be found during weaving. There are limitations to the color selection of such colored yarns.

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