Caustic soda, or known as sodium hydroxide or Lye, is the chemical that was first prepared and used by soap makers. Today, it is widely used in the textile industry for processes such as exploring, mercerization, and coloring, as an integral part of the textile-making process. You can buy caustic soda for a variety of uses.
Use of caustic soda:
Scouring is a chemical washing process used to remove unwanted material from cotton. In this process, fabrics are boiled in alkaline solutions made of caustic soda. Caustic soda forms soap with free fatty acids through a process called saponification to remove natural candles, oil, and other impurities such as the remaining seed fragments in fabrics. This process is usually a prerequisite for most finishing processes in the textile industry.
Caustic soda is also used in Mercerizing, a process used to increase strength, luster, and dye fabric affinity. In this process, caustic soda is added to the fabric to cause fiber swelling which in turn enhances the properties of the cloth. The fabric usually longs for tension to reduce depreciation, general events during the Mercerizing process.
Finally, caustic soda is used in textile coloring because most dyeing processes require a controlled pH level. Therefore, caustic soda is added to the solution to maintain the level of pH during the dyeing process.
Some other use of caustic soda includes water treatment by increasing pH water supply and as cleaning agents for cleaning channels and pipes. It is also used in processing crude oil. Fun fact, sodium hydroxide was used as a detector for carbon monoxide poisoning in the past too!