What exactly is the Liquid Ammonia Finishing Technology?

When shopping online, you may come across a term called "Liquid Ammonia Finishing Technology". Commonly, there are also similar terms such as "liquid ammonia finishing", "liquid ammonia mercerization", "liquid ammonia cotton", and "liquid ammonia cutting-edge technology". Are you feeling completely confused? In fact, all these terms refer to the same thing – liquid ammonia finishing. So, what exactly is it? And what functions does it have? Today, I'm going to introduce it to you.

Liquid Ammonia Finishing Technology (Liquid Ammonia Technology) is a high-end post-finishing process used to improve the performance of cotton fabrics. A simple popular science explanation of its principle in one sentence is: using liquid ammonia (not ammonia water) at -34°C to instantly penetrate into the interior of cotton fibers, reorganize the structure of cotton fibers, and completely transform the performance of cotton fabrics.

Put simply, it's like giving the fabric a deep molecular SPA from head to toe and inside out.

If you are still interested in learning more about the underlying principles and related knowledge, please keep reading.

To clearly explain the principle of liquid ammonia finishing, we first need to introduce the characteristics of cotton fibers.

Although ordinary cotton fibers are comfortable and skin-friendly, with good breathability and hygroscopicity, they have problems such as being prone to shrinking, wrinkling, pilling, and lacking luster. This is determined by the structure of the cotton fibers themselves.

In order to address/improve the above-mentioned shortcomings of cotton fibers, ordinary mercerization and liquid ammonia finishing technologies came into being.

Ordinary mercerization uses water and caustic soda to cause cotton fibers to rapidly absorb water and swell through a chemical reaction. This makes the cross - section of cotton fibers change from a kidney - shape to an oval shape. During this swelling process, the natural twists on the surface of the longitudinal section of cotton fibers are also reduced, making them smoother. At the same time, it changes the molecular arrangement structure of cotton fibers, resulting in higher stability

Therefore, the cotton fabric treated with mercerization will have better wrinkle resistance, stability and luster. The surface of the fabric has a silk-like luster, which is where the name "mercerization" comes from. However, ordinary caustic soda mercerization has problems such as incomplete treatment, damage to the fiber surface, possible residue of lye due to incomplete washing, as well as high energy consumption and high pollution.

For liquid ammonia finishing, liquid ammonia is used to replace caustic soda. It is mainly dominated by physical reactions and does not change the surface of cotton fibers. It conducts a rapid and thorough finishing. Since the molecular weight and viscosity of liquid ammonia are lower than those of water and caustic soda, it can reach the core of cotton fibers instantly like a "miniature injection", causing the fibers to swell from the core, and the cross-section to change from a kidney shape to an approximately round shape. At the same time, it penetrates into every corner of the cotton fibers, making the longitudinal twists on the surface disappear. This makes the mercerization effect of the cotton fabric more obvious, and also enhances its wrinkle resistance and comfort.

The cotton fabric treated with liquid ammonia not only improves its appearance and hand feel, but also enhances its comfort and breathability. Its durability is also strengthened. It is more crisp and easier to care for than ordinary cotton fabrics, making the fabric look more high-end and textured. It has a better finishing effect than ordinary mercerization and is also more environmentally friendly. It can still maintain a good hand feel after repeated washing.

In fact, liquid ammonia finishing is not a cutting-edge technology that has just been developed. It was born in the United States in the 1930s. It was first used in pure cotton denim in the 1970s, but it was not widely popularized due to cost and equipment limitations. In the 1980s, the wave of synthetic fibers made this technology less popular. China introduced the equipment in 1982 but failed to promote it either. It was not until the end of the 1990s, with the return of natural fibers such as cotton, that this technology regained its vitality.

So why hasn't such a good liquid ammonia finishing technology been widely used? The main reason is that the technical threshold and cost requirements of liquid ammonia finishing are extremely high.

Just from the word itself, we can tell that ammonia is in a gaseous state at room temperature. To turn ammonia gas into a liquid state and treat the fabric, professional equipment systems and a supporting safe production environment are required. The cost of a set of liquid ammonia finishing equipment is at least 20 to 30 million yuan, and for expensive ones, it is even close to 100 million yuan. Therefore, only large and powerful textile processing enterprises have the ability to purchase and put it into production, such as Shengtai, Lutai, and Esquel. Until now, there are only more than a dozen liquid ammonia production lines in China in total.

Therefore, the cost of liquid ammonia finishing is very high, and it is truly a high-end textile manufacturing process. It is selected by many high-end brands and high-grade products. Precisely because of the cost and production capacity issues, in recent years, many products that use ordinary mercerization to imitate liquid ammonia finishing have emerged in the market. Some unscrupulous merchants play with words or make false advertisements to deceive consumers.
 

Here are some tips to avoid falling into traps:
"Mercerized texture like that of liquid ammonia treatment" ≠ True liquid ammonia finishing
"Mercerization treatment with a liquid ammonia feel" ≠ True liquid ammonia finishing
Try to choose products from regular brands/manufacturers.
The next time you come across the term "Liquid Ammonia Finishing Technology", you'll be able to make the right choice.